fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/percpu_counter.h>
  28 #include "hash.h"
  29 #include "tree-log.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "volumes.h"
  33 #include "raid56.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36 #include "free-space-tree.h"
  37 #include "math.h"
  38 #include "sysfs.h"
  39 #include "qgroup.h"
  40
  41 #undef SCRAMBLE_DELAYED_REFS
  42
  43 /*
  44  * control flags for do_chunk_alloc's force field
  45  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  46  * if we really need one.
  47  *
  48  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  49  * if we have very few chunks already allocated.  This is
  50  * used as part of the clustering code to help make sure
  51  * we have a good pool of storage to cluster in, without
  52  * filling the FS with empty chunks
  53  *
  54  * CHUNK_ALLOC_FORCE means it must try to allocate one
  55  *
  56  */
  57 enum {
  58         CHUNK_ALLOC_NO_FORCE = 0,
  59         CHUNK_ALLOC_LIMITED = 1,
  60         CHUNK_ALLOC_FORCE = 2,
  61 };
  62
  63 static int update_block_group(struct btrfs_trans_handle *trans,
  64                               struct btrfs_root *root, u64 bytenr,
  65                               u64 num_bytes, int alloc);
  66 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  67                                 struct btrfs_root *root,
  68                                 struct btrfs_delayed_ref_node *node, u64 parent,
  69                                 u64 root_objectid, u64 owner_objectid,
  70                                 u64 owner_offset, int refs_to_drop,
  71                                 struct btrfs_delayed_extent_op *extra_op);
  72 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  73                                     struct extent_buffer *leaf,
  74                                     struct btrfs_extent_item *ei);
  75 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  76                                       struct btrfs_root *root,
  77                                       u64 parent, u64 root_objectid,
  78                                       u64 flags, u64 owner, u64 offset,
  79                                       struct btrfs_key *ins, int ref_mod);
  80 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  81                                      struct btrfs_root *root,
  82                                      u64 parent, u64 root_objectid,
  83                                      u64 flags, struct btrfs_disk_key *key,
  84                                      int level, struct btrfs_key *ins);
  85 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  86                           struct btrfs_root *extent_root, u64 flags,
  87                           int force);
  88 static int find_next_key(struct btrfs_path *path, int level,
  89                          struct btrfs_key *key);
  90 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
  91                             int dump_block_groups);
  92 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
  93                                     u64 ram_bytes, u64 num_bytes, int delalloc);
  94 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
  95                                      u64 num_bytes, int delalloc);
  96 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
  97                                u64 num_bytes);
  98 int btrfs_pin_extent(struct btrfs_root *root,
  99                      u64 bytenr, u64 num_bytes, int reserved);
 100 static int __reserve_metadata_bytes(struct btrfs_root *root,
 101                                     struct btrfs_space_info *space_info,
 102                                     u64 orig_bytes,
 103                                     enum btrfs_reserve_flush_enum flush);
 104 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
 105                                      struct btrfs_space_info *space_info,
 106                                      u64 num_bytes);
 107 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
 108                                      struct btrfs_space_info *space_info,
 109                                      u64 num_bytes);
 110
 111 static noinline int
 112 block_group_cache_done(struct btrfs_block_group_cache *cache)
 113 {
 114         smp_mb();
 115         return cache->cached == BTRFS_CACHE_FINISHED ||
 116                 cache->cached == BTRFS_CACHE_ERROR;
 117 }
 118
 119 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 120 {
 121         return (cache->flags & bits) == bits;
 122 }
 123
 124 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 125 {
 126         atomic_inc(&cache->count);
 127 }
 128
 129 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 130 {
 131         if (atomic_dec_and_test(&cache->count)) {
 132                 WARN_ON(cache->pinned > 0);
 133                 WARN_ON(cache->reserved > 0);
 134                 kfree(cache->free_space_ctl);
 135                 kfree(cache);
 136         }
 137 }
 138
 139 /*
 140  * this adds the block group to the fs_info rb tree for the block group
 141  * cache
 142  */
 143 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 144                                 struct btrfs_block_group_cache *block_group)
 145 {
 146         struct rb_node **p;
 147         struct rb_node *parent = NULL;
 148         struct btrfs_block_group_cache *cache;
 149
 150         spin_lock(&info->block_group_cache_lock);
 151         p = &info->block_group_cache_tree.rb_node;
 152
 153         while (*p) {
 154                 parent = *p;
 155                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 156                                  cache_node);
 157                 if (block_group->key.objectid < cache->key.objectid) {
 158                         p = &(*p)->rb_left;
 159                 } else if (block_group->key.objectid > cache->key.objectid) {
 160                         p = &(*p)->rb_right;
 161                 } else {
 162                         spin_unlock(&info->block_group_cache_lock);
 163                         return -EEXIST;
 164                 }
 165         }
 166
 167         rb_link_node(&block_group->cache_node, parent, p);
 168         rb_insert_color(&block_group->cache_node,
 169                         &info->block_group_cache_tree);
 170
 171         if (info->first_logical_byte > block_group->key.objectid)
 172                 info->first_logical_byte = block_group->key.objectid;
 173
 174         spin_unlock(&info->block_group_cache_lock);
 175
 176         return 0;
 177 }
 178
 179 /*
 180  * This will return the block group at or after bytenr if contains is 0, else
 181  * it will return the block group that contains the bytenr
 182  */
 183 static struct btrfs_block_group_cache *
 184 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 185                               int contains)
 186 {
 187         struct btrfs_block_group_cache *cache, *ret = NULL;
 188         struct rb_node *n;
 189         u64 end, start;
 190
 191         spin_lock(&info->block_group_cache_lock);
 192         n = info->block_group_cache_tree.rb_node;
 193
 194         while (n) {
 195                 cache = rb_entry(n, struct btrfs_block_group_cache,
 196                                  cache_node);
 197                 end = cache->key.objectid + cache->key.offset - 1;
 198                 start = cache->key.objectid;
 199
 200                 if (bytenr < start) {
 201                         if (!contains && (!ret || start < ret->key.objectid))
 202                                 ret = cache;
 203                         n = n->rb_left;
 204                 } else if (bytenr > start) {
 205                         if (contains && bytenr <= end) {
 206                                 ret = cache;
 207                                 break;
 208                         }
 209                         n = n->rb_right;
 210                 } else {
 211                         ret = cache;
 212                         break;
 213                 }
 214         }
 215         if (ret) {
 216                 btrfs_get_block_group(ret);
 217                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 218                         info->first_logical_byte = ret->key.objectid;
 219         }
 220         spin_unlock(&info->block_group_cache_lock);
 221
 222         return ret;
 223 }
 224
 225 static int add_excluded_extent(struct btrfs_root *root,
 226                                u64 start, u64 num_bytes)
 227 {
 228         u64 end = start + num_bytes - 1;
 229         set_extent_bits(&root->fs_info->freed_extents[0],
 230                         start, end, EXTENT_UPTODATE);
 231         set_extent_bits(&root->fs_info->freed_extents[1],
 232                         start, end, EXTENT_UPTODATE);
 233         return 0;
 234 }
 235
 236 static void free_excluded_extents(struct btrfs_root *root,
 237                                   struct btrfs_block_group_cache *cache)
 238 {
 239         u64 start, end;
 240
 241         start = cache->key.objectid;
 242         end = start + cache->key.offset - 1;
 243
 244         clear_extent_bits(&root->fs_info->freed_extents[0],
 245                           start, end, EXTENT_UPTODATE);
 246         clear_extent_bits(&root->fs_info->freed_extents[1],
 247                           start, end, EXTENT_UPTODATE);
 248 }
 249
 250 static int exclude_super_stripes(struct btrfs_root *root,
 251                                  struct btrfs_block_group_cache *cache)
 252 {
 253         u64 bytenr;
 254         u64 *logical;
 255         int stripe_len;
 256         int i, nr, ret;
 257
 258         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 259                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 260                 cache->bytes_super += stripe_len;
 261                 ret = add_excluded_extent(root, cache->key.objectid,
 262                                           stripe_len);
 263                 if (ret)
 264                         return ret;
 265         }
 266
 267         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 268                 bytenr = btrfs_sb_offset(i);
 269                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 270                                        cache->key.objectid, bytenr,
 271                                        0, &logical, &nr, &stripe_len);
 272                 if (ret)
 273                         return ret;
 274
 275                 while (nr--) {
 276                         u64 start, len;
 277
 278                         if (logical[nr] > cache->key.objectid +
 279                             cache->key.offset)
 280                                 continue;
 281
 282                         if (logical[nr] + stripe_len <= cache->key.objectid)
 283                                 continue;
 284
 285                         start = logical[nr];
 286                         if (start < cache->key.objectid) {
 287                                 start = cache->key.objectid;
 288                                 len = (logical[nr] + stripe_len) - start;
 289                         } else {
 290                                 len = min_t(u64, stripe_len,
 291                                             cache->key.objectid +
 292                                             cache->key.offset - start);
 293                         }
 294
 295                         cache->bytes_super += len;
 296                         ret = add_excluded_extent(root, start, len);
 297                         if (ret) {
 298                                 kfree(logical);
 299                                 return ret;
 300                         }
 301                 }
 302
 303                 kfree(logical);
 304         }
 305         return 0;
 306 }
 307
 308 static struct btrfs_caching_control *
 309 get_caching_control(struct btrfs_block_group_cache *cache)
 310 {
 311         struct btrfs_caching_control *ctl;
 312
 313         spin_lock(&cache->lock);
 314         if (!cache->caching_ctl) {
 315                 spin_unlock(&cache->lock);
 316                 return NULL;
 317         }
 318
 319         ctl = cache->caching_ctl;
 320         atomic_inc(&ctl->count);
 321         spin_unlock(&cache->lock);
 322         return ctl;
 323 }
 324
 325 static void put_caching_control(struct btrfs_caching_control *ctl)
 326 {
 327         if (atomic_dec_and_test(&ctl->count))
 328                 kfree(ctl);
 329 }
 330
 331 #ifdef CONFIG_BTRFS_DEBUG
 332 static void fragment_free_space(struct btrfs_root *root,
 333                                 struct btrfs_block_group_cache *block_group)
 334 {
 335         u64 start = block_group->key.objectid;
 336         u64 len = block_group->key.offset;
 337         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 338                 root->nodesize : root->sectorsize;
 339         u64 step = chunk << 1;
 340
 341         while (len > chunk) {
 342                 btrfs_remove_free_space(block_group, start, chunk);
 343                 start += step;
 344                 if (len < step)
 345                         len = 0;
 346                 else
 347                         len -= step;
 348         }
 349 }
 350 #endif
 351
 352 /*
 353  * this is only called by cache_block_group, since we could have freed extents
 354  * we need to check the pinned_extents for any extents that can't be used yet
 355  * since their free space will be released as soon as the transaction commits.
 356  */
 357 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 358                        struct btrfs_fs_info *info, u64 start, u64 end)
 359 {
 360         u64 extent_start, extent_end, size, total_added = 0;
 361         int ret;
 362
 363         while (start < end) {
 364                 ret = find_first_extent_bit(info->pinned_extents, start,
 365                                             &extent_start, &extent_end,
 366                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 367                                             NULL);
 368                 if (ret)
 369                         break;
 370
 371                 if (extent_start <= start) {
 372                         start = extent_end + 1;
 373                 } else if (extent_start > start && extent_start < end) {
 374                         size = extent_start - start;
 375                         total_added += size;
 376                         ret = btrfs_add_free_space(block_group, start,
 377                                                    size);
 378                         BUG_ON(ret); /* -ENOMEM or logic error */
 379                         start = extent_end + 1;
 380                 } else {
 381                         break;
 382                 }
 383         }
 384
 385         if (start < end) {
 386                 size = end - start;
 387                 total_added += size;
 388                 ret = btrfs_add_free_space(block_group, start, size);
 389                 BUG_ON(ret); /* -ENOMEM or logic error */
 390         }
 391
 392         return total_added;
 393 }
 394
 395 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 396 {
 397         struct btrfs_block_group_cache *block_group;
 398         struct btrfs_fs_info *fs_info;
 399         struct btrfs_root *extent_root;
 400         struct btrfs_path *path;
 401         struct extent_buffer *leaf;
 402         struct btrfs_key key;
 403         u64 total_found = 0;
 404         u64 last = 0;
 405         u32 nritems;
 406         int ret;
 407         bool wakeup = true;
 408
 409         block_group = caching_ctl->block_group;
 410         fs_info = block_group->fs_info;
 411         extent_root = fs_info->extent_root;
 412
 413         path = btrfs_alloc_path();
 414         if (!path)
 415                 return -ENOMEM;
 416
 417         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 418
 419 #ifdef CONFIG_BTRFS_DEBUG
 420         /*
 421          * If we're fragmenting we don't want to make anybody think we can
 422          * allocate from this block group until we've had a chance to fragment
 423          * the free space.
 424          */
 425         if (btrfs_should_fragment_free_space(extent_root, block_group))
 426                 wakeup = false;
 427 #endif
 428         /*
 429          * We don't want to deadlock with somebody trying to allocate a new
 430          * extent for the extent root while also trying to search the extent
 431          * root to add free space.  So we skip locking and search the commit
 432          * root, since its read-only
 433          */
 434         path->skip_locking = 1;
 435         path->search_commit_root = 1;
 436         path->reada = READA_FORWARD;
 437
 438         key.objectid = last;
 439         key.offset = 0;
 440         key.type = BTRFS_EXTENT_ITEM_KEY;
 441
 442 next:
 443         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 444         if (ret < 0)
 445                 goto out;
 446
 447         leaf = path->nodes[0];
 448         nritems = btrfs_header_nritems(leaf);
 449
 450         while (1) {
 451                 if (btrfs_fs_closing(fs_info) > 1) {
 452                         last = (u64)-1;
 453                         break;
 454                 }
 455
 456                 if (path->slots[0] < nritems) {
 457                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 458                 } else {
 459                         ret = find_next_key(path, 0, &key);
 460                         if (ret)
 461                                 break;
 462
 463                         if (need_resched() ||
 464                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 465                                 if (wakeup)
 466                                         caching_ctl->progress = last;
 467                                 btrfs_release_path(path);
 468                                 up_read(&fs_info->commit_root_sem);
 469                                 mutex_unlock(&caching_ctl->mutex);
 470                                 cond_resched();
 471                                 mutex_lock(&caching_ctl->mutex);
 472                                 down_read(&fs_info->commit_root_sem);
 473                                 goto next;
 474                         }
 475
 476                         ret = btrfs_next_leaf(extent_root, path);
 477                         if (ret < 0)
 478                                 goto out;
 479                         if (ret)
 480                                 break;
 481                         leaf = path->nodes[0];
 482                         nritems = btrfs_header_nritems(leaf);
 483                         continue;
 484                 }
 485
 486                 if (key.objectid < last) {
 487                         key.objectid = last;
 488                         key.offset = 0;
 489                         key.type = BTRFS_EXTENT_ITEM_KEY;
 490
 491                         if (wakeup)
 492                                 caching_ctl->progress = last;
 493                         btrfs_release_path(path);
 494                         goto next;
 495                 }
 496
 497                 if (key.objectid < block_group->key.objectid) {
 498                         path->slots[0]++;
 499                         continue;
 500                 }
 501
 502                 if (key.objectid >= block_group->key.objectid +
 503                     block_group->key.offset)
 504                         break;
 505
 506                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 507                     key.type == BTRFS_METADATA_ITEM_KEY) {
 508                         total_found += add_new_free_space(block_group,
 509                                                           fs_info, last,
 510                                                           key.objectid);
 511                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 512                                 last = key.objectid +
 513                                         fs_info->tree_root->nodesize;
 514                         else
 515                                 last = key.objectid + key.offset;
 516
 517                         if (total_found > CACHING_CTL_WAKE_UP) {
 518                                 total_found = 0;
 519                                 if (wakeup)
 520                                         wake_up(&caching_ctl->wait);
 521                         }
 522                 }
 523                 path->slots[0]++;
 524         }
 525         ret = 0;
 526
 527         total_found += add_new_free_space(block_group, fs_info, last,
 528                                           block_group->key.objectid +
 529                                           block_group->key.offset);
 530         caching_ctl->progress = (u64)-1;
 531
 532 out:
 533         btrfs_free_path(path);
 534         return ret;
 535 }
 536
 537 static noinline void caching_thread(struct btrfs_work *work)
 538 {
 539         struct btrfs_block_group_cache *block_group;
 540         struct btrfs_fs_info *fs_info;
 541         struct btrfs_caching_control *caching_ctl;
 542         struct btrfs_root *extent_root;
 543         int ret;
 544
 545         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 546         block_group = caching_ctl->block_group;
 547         fs_info = block_group->fs_info;
 548         extent_root = fs_info->extent_root;
 549
 550         mutex_lock(&caching_ctl->mutex);
 551         down_read(&fs_info->commit_root_sem);
 552
 553         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 554                 ret = load_free_space_tree(caching_ctl);
 555         else
 556                 ret = load_extent_tree_free(caching_ctl);
 557
 558         spin_lock(&block_group->lock);
 559         block_group->caching_ctl = NULL;
 560         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 561         spin_unlock(&block_group->lock);
 562
 563 #ifdef CONFIG_BTRFS_DEBUG
 564         if (btrfs_should_fragment_free_space(extent_root, block_group)) {
 565                 u64 bytes_used;
 566
 567                 spin_lock(&block_group->space_info->lock);
 568                 spin_lock(&block_group->lock);
 569                 bytes_used = block_group->key.offset -
 570                         btrfs_block_group_used(&block_group->item);
 571                 block_group->space_info->bytes_used += bytes_used >> 1;
 572                 spin_unlock(&block_group->lock);
 573                 spin_unlock(&block_group->space_info->lock);
 574                 fragment_free_space(extent_root, block_group);
 575         }
 576 #endif
 577
 578         caching_ctl->progress = (u64)-1;
 579
 580         up_read(&fs_info->commit_root_sem);
 581         free_excluded_extents(fs_info->extent_root, block_group);
 582         mutex_unlock(&caching_ctl->mutex);
 583
 584         wake_up(&caching_ctl->wait);
 585
 586         put_caching_control(caching_ctl);
 587         btrfs_put_block_group(block_group);
 588 }
 589
 590 static int cache_block_group(struct btrfs_block_group_cache *cache,
 591                              int load_cache_only)
 592 {
 593         DEFINE_WAIT(wait);
 594         struct btrfs_fs_info *fs_info = cache->fs_info;
 595         struct btrfs_caching_control *caching_ctl;
 596         int ret = 0;
 597
 598         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 599         if (!caching_ctl)
 600                 return -ENOMEM;
 601
 602         INIT_LIST_HEAD(&caching_ctl->list);
 603         mutex_init(&caching_ctl->mutex);
 604         init_waitqueue_head(&caching_ctl->wait);
 605         caching_ctl->block_group = cache;
 606         caching_ctl->progress = cache->key.objectid;
 607         atomic_set(&caching_ctl->count, 1);
 608         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 609                         caching_thread, NULL, NULL);
 610
 611         spin_lock(&cache->lock);
 612         /*
 613          * This should be a rare occasion, but this could happen I think in the
 614          * case where one thread starts to load the space cache info, and then
 615          * some other thread starts a transaction commit which tries to do an
 616          * allocation while the other thread is still loading the space cache
 617          * info.  The previous loop should have kept us from choosing this block
 618          * group, but if we've moved to the state where we will wait on caching
 619          * block groups we need to first check if we're doing a fast load here,
 620          * so we can wait for it to finish, otherwise we could end up allocating
 621          * from a block group who's cache gets evicted for one reason or
 622          * another.
 623          */
 624         while (cache->cached == BTRFS_CACHE_FAST) {
 625                 struct btrfs_caching_control *ctl;
 626
 627                 ctl = cache->caching_ctl;
 628                 atomic_inc(&ctl->count);
 629                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 630                 spin_unlock(&cache->lock);
 631
 632                 schedule();
 633
 634                 finish_wait(&ctl->wait, &wait);
 635                 put_caching_control(ctl);
 636                 spin_lock(&cache->lock);
 637         }
 638
 639         if (cache->cached != BTRFS_CACHE_NO) {
 640                 spin_unlock(&cache->lock);
 641                 kfree(caching_ctl);
 642                 return 0;
 643         }
 644         WARN_ON(cache->caching_ctl);
 645         cache->caching_ctl = caching_ctl;
 646         cache->cached = BTRFS_CACHE_FAST;
 647         spin_unlock(&cache->lock);
 648
 649         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 650                 mutex_lock(&caching_ctl->mutex);
 651                 ret = load_free_space_cache(fs_info, cache);
 652
 653                 spin_lock(&cache->lock);
 654                 if (ret == 1) {
 655                         cache->caching_ctl = NULL;
 656                         cache->cached = BTRFS_CACHE_FINISHED;
 657                         cache->last_byte_to_unpin = (u64)-1;
 658                         caching_ctl->progress = (u64)-1;
 659                 } else {
 660                         if (load_cache_only) {
 661                                 cache->caching_ctl = NULL;
 662                                 cache->cached = BTRFS_CACHE_NO;
 663                         } else {
 664                                 cache->cached = BTRFS_CACHE_STARTED;
 665                                 cache->has_caching_ctl = 1;
 666                         }
 667                 }
 668                 spin_unlock(&cache->lock);
 669 #ifdef CONFIG_BTRFS_DEBUG
 670                 if (ret == 1 &&
 671                     btrfs_should_fragment_free_space(fs_info->extent_root,
 672                                                      cache)) {
 673                         u64 bytes_used;
 674
 675                         spin_lock(&cache->space_info->lock);
 676                         spin_lock(&cache->lock);
 677                         bytes_used = cache->key.offset -
 678                                 btrfs_block_group_used(&cache->item);
 679                         cache->space_info->bytes_used += bytes_used >> 1;
 680                         spin_unlock(&cache->lock);
 681                         spin_unlock(&cache->space_info->lock);
 682                         fragment_free_space(fs_info->extent_root, cache);
 683                 }
 684 #endif
 685                 mutex_unlock(&caching_ctl->mutex);
 686
 687                 wake_up(&caching_ctl->wait);
 688                 if (ret == 1) {
 689                         put_caching_control(caching_ctl);
 690                         free_excluded_extents(fs_info->extent_root, cache);
 691                         return 0;
 692                 }
 693         } else {
 694                 /*
 695                  * We're either using the free space tree or no caching at all.
 696                  * Set cached to the appropriate value and wakeup any waiters.
 697                  */
 698                 spin_lock(&cache->lock);
 699                 if (load_cache_only) {
 700                         cache->caching_ctl = NULL;
 701                         cache->cached = BTRFS_CACHE_NO;
 702                 } else {
 703                         cache->cached = BTRFS_CACHE_STARTED;
 704                         cache->has_caching_ctl = 1;
 705                 }
 706                 spin_unlock(&cache->lock);
 707                 wake_up(&caching_ctl->wait);
 708         }
 709
 710         if (load_cache_only) {
 711                 put_caching_control(caching_ctl);
 712                 return 0;
 713         }
 714
 715         down_write(&fs_info->commit_root_sem);
 716         atomic_inc(&caching_ctl->count);
 717         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 718         up_write(&fs_info->commit_root_sem);
 719
 720         btrfs_get_block_group(cache);
 721
 722         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 723
 724         return ret;
 725 }
 726
 727 /*
 728  * return the block group that starts at or after bytenr
 729  */
 730 static struct btrfs_block_group_cache *
 731 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 732 {
 733         return block_group_cache_tree_search(info, bytenr, 0);
 734 }
 735
 736 /*
 737  * return the block group that contains the given bytenr
 738  */
 739 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 740                                                  struct btrfs_fs_info *info,
 741                                                  u64 bytenr)
 742 {
 743         return block_group_cache_tree_search(info, bytenr, 1);
 744 }
 745
 746 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 747                                                   u64 flags)
 748 {
 749         struct list_head *head = &info->space_info;
 750         struct btrfs_space_info *found;
 751
 752         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 753
 754         rcu_read_lock();
 755         list_for_each_entry_rcu(found, head, list) {
 756                 if (found->flags & flags) {
 757                         rcu_read_unlock();
 758                         return found;
 759                 }
 760         }
 761         rcu_read_unlock();
 762         return NULL;
 763 }
 764
 765 /*
 766  * after adding space to the filesystem, we need to clear the full flags
 767  * on all the space infos.
 768  */
 769 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 770 {
 771         struct list_head *head = &info->space_info;
 772         struct btrfs_space_info *found;
 773
 774         rcu_read_lock();
 775         list_for_each_entry_rcu(found, head, list)
 776                 found->full = 0;
 777         rcu_read_unlock();
 778 }
 779
 780 /* simple helper to search for an existing data extent at a given offset */
 781 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
 782 {
 783         int ret;
 784         struct btrfs_key key;
 785         struct btrfs_path *path;
 786
 787         path = btrfs_alloc_path();
 788         if (!path)
 789                 return -ENOMEM;
 790
 791         key.objectid = start;
 792         key.offset = len;
 793         key.type = BTRFS_EXTENT_ITEM_KEY;
 794         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 795                                 0, 0);
 796         btrfs_free_path(path);
 797         return ret;
 798 }
 799
 800 /*
 801  * helper function to lookup reference count and flags of a tree block.
 802  *
 803  * the head node for delayed ref is used to store the sum of all the
 804  * reference count modifications queued up in the rbtree. the head
 805  * node may also store the extent flags to set. This way you can check
 806  * to see what the reference count and extent flags would be if all of
 807  * the delayed refs are not processed.
 808  */
 809 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 810                              struct btrfs_root *root, u64 bytenr,
 811                              u64 offset, int metadata, u64 *refs, u64 *flags)
 812 {
 813         struct btrfs_delayed_ref_head *head;
 814         struct btrfs_delayed_ref_root *delayed_refs;
 815         struct btrfs_path *path;
 816         struct btrfs_extent_item *ei;
 817         struct extent_buffer *leaf;
 818         struct btrfs_key key;
 819         u32 item_size;
 820         u64 num_refs;
 821         u64 extent_flags;
 822         int ret;
 823
 824         /*
 825          * If we don't have skinny metadata, don't bother doing anything
 826          * different
 827          */
 828         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 829                 offset = root->nodesize;
 830                 metadata = 0;
 831         }
 832
 833         path = btrfs_alloc_path();
 834         if (!path)
 835                 return -ENOMEM;
 836
 837         if (!trans) {
 838                 path->skip_locking = 1;
 839                 path->search_commit_root = 1;
 840         }
 841
 842 search_again:
 843         key.objectid = bytenr;
 844         key.offset = offset;
 845         if (metadata)
 846                 key.type = BTRFS_METADATA_ITEM_KEY;
 847         else
 848                 key.type = BTRFS_EXTENT_ITEM_KEY;
 849
 850         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 851                                 &key, path, 0, 0);
 852         if (ret < 0)
 853                 goto out_free;
 854
 855         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 856                 if (path->slots[0]) {
 857                         path->slots[0]--;
 858                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 859                                               path->slots[0]);
 860                         if (key.objectid == bytenr &&
 861                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 862                             key.offset == root->nodesize)
 863                                 ret = 0;
 864                 }
 865         }
 866
 867         if (ret == 0) {
 868                 leaf = path->nodes[0];
 869                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 870                 if (item_size >= sizeof(*ei)) {
 871                         ei = btrfs_item_ptr(leaf, path->slots[0],
 872                                             struct btrfs_extent_item);
 873                         num_refs = btrfs_extent_refs(leaf, ei);
 874                         extent_flags = btrfs_extent_flags(leaf, ei);
 875                 } else {
 876 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 877                         struct btrfs_extent_item_v0 *ei0;
 878                         BUG_ON(item_size != sizeof(*ei0));
 879                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 880                                              struct btrfs_extent_item_v0);
 881                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 882                         /* FIXME: this isn't correct for data */
 883                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 884 #else
 885                         BUG();
 886 #endif
 887                 }
 888                 BUG_ON(num_refs == 0);
 889         } else {
 890                 num_refs = 0;
 891                 extent_flags = 0;
 892                 ret = 0;
 893         }
 894
 895         if (!trans)
 896                 goto out;
 897
 898         delayed_refs = &trans->transaction->delayed_refs;
 899         spin_lock(&delayed_refs->lock);
 900         head = btrfs_find_delayed_ref_head(trans, bytenr);
 901         if (head) {
 902                 if (!mutex_trylock(&head->mutex)) {
 903                         atomic_inc(&head->node.refs);
 904                         spin_unlock(&delayed_refs->lock);
 905
 906                         btrfs_release_path(path);
 907
 908                         /*
 909                          * Mutex was contended, block until it's released and try
 910                          * again
 911                          */
 912                         mutex_lock(&head->mutex);
 913                         mutex_unlock(&head->mutex);
 914                         btrfs_put_delayed_ref(&head->node);
 915                         goto search_again;
 916                 }
 917                 spin_lock(&head->lock);
 918                 if (head->extent_op && head->extent_op->update_flags)
 919                         extent_flags |= head->extent_op->flags_to_set;
 920                 else
 921                         BUG_ON(num_refs == 0);
 922
 923                 num_refs += head->node.ref_mod;
 924                 spin_unlock(&head->lock);
 925                 mutex_unlock(&head->mutex);
 926         }
 927         spin_unlock(&delayed_refs->lock);
 928 out:
 929         WARN_ON(num_refs == 0);
 930         if (refs)
 931                 *refs = num_refs;
 932         if (flags)
 933                 *flags = extent_flags;
 934 out_free:
 935         btrfs_free_path(path);
 936         return ret;
 937 }
 938
 939 /*
 940  * Back reference rules.  Back refs have three main goals:
 941  *
 942  * 1) differentiate between all holders of references to an extent so that
 943  *    when a reference is dropped we can make sure it was a valid reference
 944  *    before freeing the extent.
 945  *
 946  * 2) Provide enough information to quickly find the holders of an extent
 947  *    if we notice a given block is corrupted or bad.
 948  *
 949  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 950  *    maintenance.  This is actually the same as #2, but with a slightly
 951  *    different use case.
 952  *
 953  * There are two kinds of back refs. The implicit back refs is optimized
 954  * for pointers in non-shared tree blocks. For a given pointer in a block,
 955  * back refs of this kind provide information about the block's owner tree
 956  * and the pointer's key. These information allow us to find the block by
 957  * b-tree searching. The full back refs is for pointers in tree blocks not
 958  * referenced by their owner trees. The location of tree block is recorded
 959  * in the back refs. Actually the full back refs is generic, and can be
 960  * used in all cases the implicit back refs is used. The major shortcoming
 961  * of the full back refs is its overhead. Every time a tree block gets
 962  * COWed, we have to update back refs entry for all pointers in it.
 963  *
 964  * For a newly allocated tree block, we use implicit back refs for
 965  * pointers in it. This means most tree related operations only involve
 966  * implicit back refs. For a tree block created in old transaction, the
 967  * only way to drop a reference to it is COW it. So we can detect the
 968  * event that tree block loses its owner tree's reference and do the
 969  * back refs conversion.
 970  *
 971  * When a tree block is COWed through a tree, there are four cases:
 972  *
 973  * The reference count of the block is one and the tree is the block's
 974  * owner tree. Nothing to do in this case.
 975  *
 976  * The reference count of the block is one and the tree is not the
 977  * block's owner tree. In this case, full back refs is used for pointers
 978  * in the block. Remove these full back refs, add implicit back refs for
 979  * every pointers in the new block.
 980  *
 981  * The reference count of the block is greater than one and the tree is
 982  * the block's owner tree. In this case, implicit back refs is used for
 983  * pointers in the block. Add full back refs for every pointers in the
 984  * block, increase lower level extents' reference counts. The original
 985  * implicit back refs are entailed to the new block.
 986  *
 987  * The reference count of the block is greater than one and the tree is
 988  * not the block's owner tree. Add implicit back refs for every pointer in
 989  * the new block, increase lower level extents' reference count.
 990  *
 991  * Back Reference Key composing:
 992  *
 993  * The key objectid corresponds to the first byte in the extent,
 994  * The key type is used to differentiate between types of back refs.
 995  * There are different meanings of the key offset for different types
 996  * of back refs.
 997  *
 998  * File extents can be referenced by:
 999  *
1000  * - multiple snapshots, subvolumes, or different generations in one subvol
1001  * - different files inside a single subvolume
1002  * - different offsets inside a file (bookend extents in file.c)
1003  *
1004  * The extent ref structure for the implicit back refs has fields for:
1005  *
1006  * - Objectid of the subvolume root
1007  * - objectid of the file holding the reference
1008  * - original offset in the file
1009  * - how many bookend extents
1010  *
1011  * The key offset for the implicit back refs is hash of the first
1012  * three fields.
1013  *
1014  * The extent ref structure for the full back refs has field for:
1015  *
1016  * - number of pointers in the tree leaf
1017  *
1018  * The key offset for the implicit back refs is the first byte of
1019  * the tree leaf
1020  *
1021  * When a file extent is allocated, The implicit back refs is used.
1022  * the fields are filled in:
1023  *
1024  *     (root_key.objectid, inode objectid, offset in file, 1)
1025  *
1026  * When a file extent is removed file truncation, we find the
1027  * corresponding implicit back refs and check the following fields:
1028  *
1029  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1030  *
1031  * Btree extents can be referenced by:
1032  *
1033  * - Different subvolumes
1034  *
1035  * Both the implicit back refs and the full back refs for tree blocks
1036  * only consist of key. The key offset for the implicit back refs is
1037  * objectid of block's owner tree. The key offset for the full back refs
1038  * is the first byte of parent block.
1039  *
1040  * When implicit back refs is used, information about the lowest key and
1041  * level of the tree block are required. These information are stored in
1042  * tree block info structure.
1043  */
1044
1045 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1046 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1047                                   struct btrfs_root *root,
1048                                   struct btrfs_path *path,
1049                                   u64 owner, u32 extra_size)
1050 {
1051         struct btrfs_extent_item *item;
1052         struct btrfs_extent_item_v0 *ei0;
1053         struct btrfs_extent_ref_v0 *ref0;
1054         struct btrfs_tree_block_info *bi;
1055         struct extent_buffer *leaf;
1056         struct btrfs_key key;
1057         struct btrfs_key found_key;
1058         u32 new_size = sizeof(*item);
1059         u64 refs;
1060         int ret;
1061
1062         leaf = path->nodes[0];
1063         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1064
1065         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1066         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1067                              struct btrfs_extent_item_v0);
1068         refs = btrfs_extent_refs_v0(leaf, ei0);
1069
1070         if (owner == (u64)-1) {
1071                 while (1) {
1072                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1073                                 ret = btrfs_next_leaf(root, path);
1074                                 if (ret < 0)
1075                                         return ret;
1076                                 BUG_ON(ret > 0); /* Corruption */
1077                                 leaf = path->nodes[0];
1078                         }
1079                         btrfs_item_key_to_cpu(leaf, &found_key,
1080                                               path->slots[0]);
1081                         BUG_ON(key.objectid != found_key.objectid);
1082                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1083                                 path->slots[0]++;
1084                                 continue;
1085                         }
1086                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1087                                               struct btrfs_extent_ref_v0);
1088                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1089                         break;
1090                 }
1091         }
1092         btrfs_release_path(path);
1093
1094         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1095                 new_size += sizeof(*bi);
1096
1097         new_size -= sizeof(*ei0);
1098         ret = btrfs_search_slot(trans, root, &key, path,
1099                                 new_size + extra_size, 1);
1100         if (ret < 0)
1101                 return ret;
1102         BUG_ON(ret); /* Corruption */
1103
1104         btrfs_extend_item(root, path, new_size);
1105
1106         leaf = path->nodes[0];
1107         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1108         btrfs_set_extent_refs(leaf, item, refs);
1109         /* FIXME: get real generation */
1110         btrfs_set_extent_generation(leaf, item, 0);
1111         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1112                 btrfs_set_extent_flags(leaf, item,
1113                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1114                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1115                 bi = (struct btrfs_tree_block_info *)(item + 1);
1116                 /* FIXME: get first key of the block */
1117                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1118                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1119         } else {
1120                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1121         }
1122         btrfs_mark_buffer_dirty(leaf);
1123         return 0;
1124 }
1125 #endif
1126
1127 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1128 {
1129         u32 high_crc = ~(u32)0;
1130         u32 low_crc = ~(u32)0;
1131         __le64 lenum;
1132
1133         lenum = cpu_to_le64(root_objectid);
1134         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1135         lenum = cpu_to_le64(owner);
1136         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1137         lenum = cpu_to_le64(offset);
1138         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1139
1140         return ((u64)high_crc << 31) ^ (u64)low_crc;
1141 }
1142
1143 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1144                                      struct btrfs_extent_data_ref *ref)
1145 {
1146         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1147                                     btrfs_extent_data_ref_objectid(leaf, ref),
1148                                     btrfs_extent_data_ref_offset(leaf, ref));
1149 }
1150
1151 static int match_extent_data_ref(struct extent_buffer *leaf,
1152                                  struct btrfs_extent_data_ref *ref,
1153                                  u64 root_objectid, u64 owner, u64 offset)
1154 {
1155         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1156             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1157             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1158                 return 0;
1159         return 1;
1160 }
1161
1162 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1163                                            struct btrfs_root *root,
1164                                            struct btrfs_path *path,
1165                                            u64 bytenr, u64 parent,
1166                                            u64 root_objectid,
1167                                            u64 owner, u64 offset)
1168 {
1169         struct btrfs_key key;
1170         struct btrfs_extent_data_ref *ref;
1171         struct extent_buffer *leaf;
1172         u32 nritems;
1173         int ret;
1174         int recow;
1175         int err = -ENOENT;
1176
1177         key.objectid = bytenr;
1178         if (parent) {
1179                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1180                 key.offset = parent;
1181         } else {
1182                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1183                 key.offset = hash_extent_data_ref(root_objectid,
1184                                                   owner, offset);
1185         }
1186 again:
1187         recow = 0;
1188         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1189         if (ret < 0) {
1190                 err = ret;
1191                 goto fail;
1192         }
1193
1194         if (parent) {
1195                 if (!ret)
1196                         return 0;
1197 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1198                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1199                 btrfs_release_path(path);
1200                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1201                 if (ret < 0) {
1202                         err = ret;
1203                         goto fail;
1204                 }
1205                 if (!ret)
1206                         return 0;
1207 #endif
1208                 goto fail;
1209         }
1210
1211         leaf = path->nodes[0];
1212         nritems = btrfs_header_nritems(leaf);
1213         while (1) {
1214                 if (path->slots[0] >= nritems) {
1215                         ret = btrfs_next_leaf(root, path);
1216                         if (ret < 0)
1217                                 err = ret;
1218                         if (ret)
1219                                 goto fail;
1220
1221                         leaf = path->nodes[0];
1222                         nritems = btrfs_header_nritems(leaf);
1223                         recow = 1;
1224                 }
1225
1226                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1227                 if (key.objectid != bytenr ||
1228                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1229                         goto fail;
1230
1231                 ref = btrfs_item_ptr(leaf, path->slots[0],
1232                                      struct btrfs_extent_data_ref);
1233
1234                 if (match_extent_data_ref(leaf, ref, root_objectid,
1235                                           owner, offset)) {
1236                         if (recow) {
1237                                 btrfs_release_path(path);
1238                                 goto again;
1239                         }
1240                         err = 0;
1241                         break;
1242                 }
1243                 path->slots[0]++;
1244         }
1245 fail:
1246         return err;
1247 }
1248
1249 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1250                                            struct btrfs_root *root,
1251                                            struct btrfs_path *path,
1252                                            u64 bytenr, u64 parent,
1253                                            u64 root_objectid, u64 owner,
1254                                            u64 offset, int refs_to_add)
1255 {
1256         struct btrfs_key key;
1257         struct extent_buffer *leaf;
1258         u32 size;
1259         u32 num_refs;
1260         int ret;
1261
1262         key.objectid = bytenr;
1263         if (parent) {
1264                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1265                 key.offset = parent;
1266                 size = sizeof(struct btrfs_shared_data_ref);
1267         } else {
1268                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1269                 key.offset = hash_extent_data_ref(root_objectid,
1270                                                   owner, offset);
1271                 size = sizeof(struct btrfs_extent_data_ref);
1272         }
1273
1274         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1275         if (ret && ret != -EEXIST)
1276                 goto fail;
1277
1278         leaf = path->nodes[0];
1279         if (parent) {
1280                 struct btrfs_shared_data_ref *ref;
1281                 ref = btrfs_item_ptr(leaf, path->slots[0],
1282                                      struct btrfs_shared_data_ref);
1283                 if (ret == 0) {
1284                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1285                 } else {
1286                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1287                         num_refs += refs_to_add;
1288                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1289                 }
1290         } else {
1291                 struct btrfs_extent_data_ref *ref;
1292                 while (ret == -EEXIST) {
1293                         ref = btrfs_item_ptr(leaf, path->slots[0],
1294                                              struct btrfs_extent_data_ref);
1295                         if (match_extent_data_ref(leaf, ref, root_objectid,
1296                                                   owner, offset))
1297                                 break;
1298                         btrfs_release_path(path);
1299                         key.offset++;
1300                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1301                                                       size);
1302                         if (ret && ret != -EEXIST)
1303                                 goto fail;
1304
1305                         leaf = path->nodes[0];
1306                 }
1307                 ref = btrfs_item_ptr(leaf, path->slots[0],
1308                                      struct btrfs_extent_data_ref);
1309                 if (ret == 0) {
1310                         btrfs_set_extent_data_ref_root(leaf, ref,
1311                                                        root_objectid);
1312                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1313                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1314                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1315                 } else {
1316                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1317                         num_refs += refs_to_add;
1318                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1319                 }
1320         }
1321         btrfs_mark_buffer_dirty(leaf);
1322         ret = 0;
1323 fail:
1324         btrfs_release_path(path);
1325         return ret;
1326 }
1327
1328 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1329                                            struct btrfs_root *root,
1330                                            struct btrfs_path *path,
1331                                            int refs_to_drop, int *last_ref)
1332 {
1333         struct btrfs_key key;
1334         struct btrfs_extent_data_ref *ref1 = NULL;
1335         struct btrfs_shared_data_ref *ref2 = NULL;
1336         struct extent_buffer *leaf;
1337         u32 num_refs = 0;
1338         int ret = 0;
1339
1340         leaf = path->nodes[0];
1341         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1342
1343         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1344                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1345                                       struct btrfs_extent_data_ref);
1346                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1347         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1348                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1349                                       struct btrfs_shared_data_ref);
1350                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1351 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1352         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1353                 struct btrfs_extent_ref_v0 *ref0;
1354                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1355                                       struct btrfs_extent_ref_v0);
1356                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1357 #endif
1358         } else {
1359                 BUG();
1360         }
1361
1362         BUG_ON(num_refs < refs_to_drop);
1363         num_refs -= refs_to_drop;
1364
1365         if (num_refs == 0) {
1366                 ret = btrfs_del_item(trans, root, path);
1367                 *last_ref = 1;
1368         } else {
1369                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1370                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1371                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1372                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1373 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1374                 else {
1375                         struct btrfs_extent_ref_v0 *ref0;
1376                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1377                                         struct btrfs_extent_ref_v0);
1378                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1379                 }
1380 #endif
1381                 btrfs_mark_buffer_dirty(leaf);
1382         }
1383         return ret;
1384 }
1385
1386 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1387                                           struct btrfs_extent_inline_ref *iref)
1388 {
1389         struct btrfs_key key;
1390         struct extent_buffer *leaf;
1391         struct btrfs_extent_data_ref *ref1;
1392         struct btrfs_shared_data_ref *ref2;
1393         u32 num_refs = 0;
1394
1395         leaf = path->nodes[0];
1396         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1397         if (iref) {
1398                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1399                     BTRFS_EXTENT_DATA_REF_KEY) {
1400                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1401                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1402                 } else {
1403                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1404                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1405                 }
1406         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1407                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1408                                       struct btrfs_extent_data_ref);
1409                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1410         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1411                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1412                                       struct btrfs_shared_data_ref);
1413                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1414 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1415         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1416                 struct btrfs_extent_ref_v0 *ref0;
1417                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1418                                       struct btrfs_extent_ref_v0);
1419                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1420 #endif
1421         } else {
1422                 WARN_ON(1);
1423         }
1424         return num_refs;
1425 }
1426
1427 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1428                                           struct btrfs_root *root,
1429                                           struct btrfs_path *path,
1430                                           u64 bytenr, u64 parent,
1431                                           u64 root_objectid)
1432 {
1433         struct btrfs_key key;
1434         int ret;
1435
1436         key.objectid = bytenr;
1437         if (parent) {
1438                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1439                 key.offset = parent;
1440         } else {
1441                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1442                 key.offset = root_objectid;
1443         }
1444
1445         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1446         if (ret > 0)
1447                 ret = -ENOENT;
1448 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1449         if (ret == -ENOENT && parent) {
1450                 btrfs_release_path(path);
1451                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1452                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1453                 if (ret > 0)
1454                         ret = -ENOENT;
1455         }
1456 #endif
1457         return ret;
1458 }
1459
1460 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1461                                           struct btrfs_root *root,
1462                                           struct btrfs_path *path,
1463                                           u64 bytenr, u64 parent,
1464                                           u64 root_objectid)
1465 {
1466         struct btrfs_key key;
1467         int ret;
1468
1469         key.objectid = bytenr;
1470         if (parent) {
1471                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1472                 key.offset = parent;
1473         } else {
1474                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1475                 key.offset = root_objectid;
1476         }
1477
1478         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1479         btrfs_release_path(path);
1480         return ret;
1481 }
1482
1483 static inline int extent_ref_type(u64 parent, u64 owner)
1484 {
1485         int type;
1486         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1487                 if (parent > 0)
1488                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1489                 else
1490                         type = BTRFS_TREE_BLOCK_REF_KEY;
1491         } else {
1492                 if (parent > 0)
1493                         type = BTRFS_SHARED_DATA_REF_KEY;
1494                 else
1495                         type = BTRFS_EXTENT_DATA_REF_KEY;
1496         }
1497         return type;
1498 }
1499
1500 static int find_next_key(struct btrfs_path *path, int level,
1501                          struct btrfs_key *key)
1502
1503 {
1504         for (; level < BTRFS_MAX_LEVEL; level++) {
1505                 if (!path->nodes[level])
1506                         break;
1507                 if (path->slots[level] + 1 >=
1508                     btrfs_header_nritems(path->nodes[level]))
1509                         continue;
1510                 if (level == 0)
1511                         btrfs_item_key_to_cpu(path->nodes[level], key,
1512                                               path->slots[level] + 1);
1513                 else
1514                         btrfs_node_key_to_cpu(path->nodes[level], key,
1515                                               path->slots[level] + 1);
1516                 return 0;
1517         }
1518         return 1;
1519 }
1520
1521 /*
1522  * look for inline back ref. if back ref is found, *ref_ret is set
1523  * to the address of inline back ref, and 0 is returned.
1524  *
1525  * if back ref isn't found, *ref_ret is set to the address where it
1526  * should be inserted, and -ENOENT is returned.
1527  *
1528  * if insert is true and there are too many inline back refs, the path
1529  * points to the extent item, and -EAGAIN is returned.
1530  *
1531  * NOTE: inline back refs are ordered in the same way that back ref
1532  *       items in the tree are ordered.
1533  */
1534 static noinline_for_stack
1535 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1536                                  struct btrfs_root *root,
1537                                  struct btrfs_path *path,
1538                                  struct btrfs_extent_inline_ref **ref_ret,
1539                                  u64 bytenr, u64 num_bytes,
1540                                  u64 parent, u64 root_objectid,
1541                                  u64 owner, u64 offset, int insert)
1542 {
1543         struct btrfs_key key;
1544         struct extent_buffer *leaf;
1545         struct btrfs_extent_item *ei;
1546         struct btrfs_extent_inline_ref *iref;
1547         u64 flags;
1548         u64 item_size;
1549         unsigned long ptr;
1550         unsigned long end;
1551         int extra_size;
1552         int type;
1553         int want;
1554         int ret;
1555         int err = 0;
1556         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1557                                                  SKINNY_METADATA);
1558
1559         key.objectid = bytenr;
1560         key.type = BTRFS_EXTENT_ITEM_KEY;
1561         key.offset = num_bytes;
1562
1563         want = extent_ref_type(parent, owner);
1564         if (insert) {
1565                 extra_size = btrfs_extent_inline_ref_size(want);
1566                 path->keep_locks = 1;
1567         } else
1568                 extra_size = -1;
1569
1570         /*
1571          * Owner is our parent level, so we can just add one to get the level
1572          * for the block we are interested in.
1573          */
1574         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1575                 key.type = BTRFS_METADATA_ITEM_KEY;
1576                 key.offset = owner;
1577         }
1578
1579 again:
1580         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1581         if (ret < 0) {
1582                 err = ret;
1583                 goto out;
1584         }
1585
1586         /*
1587          * We may be a newly converted file system which still has the old fat
1588          * extent entries for metadata, so try and see if we have one of those.
1589          */
1590         if (ret > 0 && skinny_metadata) {
1591                 skinny_metadata = false;
1592                 if (path->slots[0]) {
1593                         path->slots[0]--;
1594                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1595                                               path->slots[0]);
1596                         if (key.objectid == bytenr &&
1597                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1598                             key.offset == num_bytes)
1599                                 ret = 0;
1600                 }
1601                 if (ret) {
1602                         key.objectid = bytenr;
1603                         key.type = BTRFS_EXTENT_ITEM_KEY;
1604                         key.offset = num_bytes;
1605                         btrfs_release_path(path);
1606                         goto again;
1607                 }
1608         }
1609
1610         if (ret && !insert) {
1611                 err = -ENOENT;
1612                 goto out;
1613         } else if (WARN_ON(ret)) {
1614                 err = -EIO;
1615                 goto out;
1616         }
1617
1618         leaf = path->nodes[0];
1619         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1620 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1621         if (item_size < sizeof(*ei)) {
1622                 if (!insert) {
1623                         err = -ENOENT;
1624                         goto out;
1625                 }
1626                 ret = convert_extent_item_v0(trans, root, path, owner,
1627                                              extra_size);
1628                 if (ret < 0) {
1629                         err = ret;
1630                         goto out;
1631                 }
1632                 leaf = path->nodes[0];
1633                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1634         }
1635 #endif
1636         BUG_ON(item_size < sizeof(*ei));
1637
1638         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1639         flags = btrfs_extent_flags(leaf, ei);
1640
1641         ptr = (unsigned long)(ei + 1);
1642         end = (unsigned long)ei + item_size;
1643
1644         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1645                 ptr += sizeof(struct btrfs_tree_block_info);
1646                 BUG_ON(ptr > end);
1647         }
1648
1649         err = -ENOENT;
1650         while (1) {
1651                 if (ptr >= end) {
1652                         WARN_ON(ptr > end);
1653                         break;
1654                 }
1655                 iref = (struct btrfs_extent_inline_ref *)ptr;
1656                 type = btrfs_extent_inline_ref_type(leaf, iref);
1657                 if (want < type)
1658                         break;
1659                 if (want > type) {
1660                         ptr += btrfs_extent_inline_ref_size(type);
1661                         continue;
1662                 }
1663
1664                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1665                         struct btrfs_extent_data_ref *dref;
1666                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1667                         if (match_extent_data_ref(leaf, dref, root_objectid,
1668                                                   owner, offset)) {
1669                                 err = 0;
1670                                 break;
1671                         }
1672                         if (hash_extent_data_ref_item(leaf, dref) <
1673                             hash_extent_data_ref(root_objectid, owner, offset))
1674                                 break;
1675                 } else {
1676                         u64 ref_offset;
1677                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1678                         if (parent > 0) {
1679                                 if (parent == ref_offset) {
1680                                         err = 0;
1681                                         break;
1682                                 }
1683                                 if (ref_offset < parent)
1684                                         break;
1685                         } else {
1686                                 if (root_objectid == ref_offset) {
1687                                         err = 0;
1688                                         break;
1689                                 }
1690                                 if (ref_offset < root_objectid)
1691                                         break;
1692                         }
1693                 }
1694                 ptr += btrfs_extent_inline_ref_size(type);
1695         }
1696         if (err == -ENOENT && insert) {
1697                 if (item_size + extra_size >=
1698                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1699                         err = -EAGAIN;
1700                         goto out;
1701                 }
1702                 /*
1703                  * To add new inline back ref, we have to make sure
1704                  * there is no corresponding back ref item.
1705                  * For simplicity, we just do not add new inline back
1706                  * ref if there is any kind of item for this block
1707                  */
1708                 if (find_next_key(path, 0, &key) == 0 &&
1709                     key.objectid == bytenr &&
1710                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1711                         err = -EAGAIN;
1712                         goto out;
1713                 }
1714         }
1715         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1716 out:
1717         if (insert) {
1718                 path->keep_locks = 0;
1719                 btrfs_unlock_up_safe(path, 1);
1720         }
1721         return err;
1722 }
1723
1724 /*
1725  * helper to add new inline back ref
1726  */
1727 static noinline_for_stack
1728 void setup_inline_extent_backref(struct btrfs_root *root,
1729                                  struct btrfs_path *path,
1730                                  struct btrfs_extent_inline_ref *iref,
1731                                  u64 parent, u64 root_objectid,
1732                                  u64 owner, u64 offset, int refs_to_add,
1733                                  struct btrfs_delayed_extent_op *extent_op)
1734 {
1735         struct extent_buffer *leaf;
1736         struct btrfs_extent_item *ei;
1737         unsigned long ptr;
1738         unsigned long end;
1739         unsigned long item_offset;
1740         u64 refs;
1741         int size;
1742         int type;
1743
1744         leaf = path->nodes[0];
1745         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1746         item_offset = (unsigned long)iref - (unsigned long)ei;
1747
1748         type = extent_ref_type(parent, owner);
1749         size = btrfs_extent_inline_ref_size(type);
1750
1751         btrfs_extend_item(root, path, size);
1752
1753         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1754         refs = btrfs_extent_refs(leaf, ei);
1755         refs += refs_to_add;
1756         btrfs_set_extent_refs(leaf, ei, refs);
1757         if (extent_op)
1758                 __run_delayed_extent_op(extent_op, leaf, ei);
1759
1760         ptr = (unsigned long)ei + item_offset;
1761         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1762         if (ptr < end - size)
1763                 memmove_extent_buffer(leaf, ptr + size, ptr,
1764                                       end - size - ptr);
1765
1766         iref = (struct btrfs_extent_inline_ref *)ptr;
1767         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1768         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1769                 struct btrfs_extent_data_ref *dref;
1770                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1771                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1772                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1773                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1774                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1775         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1776                 struct btrfs_shared_data_ref *sref;
1777                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1778                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1779                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1780         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1781                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1782         } else {
1783                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1784         }
1785         btrfs_mark_buffer_dirty(leaf);
1786 }
1787
1788 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1789                                  struct btrfs_root *root,
1790                                  struct btrfs_path *path,
1791                                  struct btrfs_extent_inline_ref **ref_ret,
1792                                  u64 bytenr, u64 num_bytes, u64 parent,
1793                                  u64 root_objectid, u64 owner, u64 offset)
1794 {
1795         int ret;
1796
1797         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1798                                            bytenr, num_bytes, parent,
1799                                            root_objectid, owner, offset, 0);
1800         if (ret != -ENOENT)
1801                 return ret;
1802
1803         btrfs_release_path(path);
1804         *ref_ret = NULL;
1805
1806         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1807                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1808                                             root_objectid);
1809         } else {
1810                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1811                                              root_objectid, owner, offset);
1812         }
1813         return ret;
1814 }
1815
1816 /*
1817  * helper to update/remove inline back ref
1818  */
1819 static noinline_for_stack
1820 void update_inline_extent_backref(struct btrfs_root *root,
1821                                   struct btrfs_path *path,
1822                                   struct btrfs_extent_inline_ref *iref,
1823                                   int refs_to_mod,
1824                                   struct btrfs_delayed_extent_op *extent_op,
1825                                   int *last_ref)
1826 {
1827         struct extent_buffer *leaf;
1828         struct btrfs_extent_item *ei;
1829         struct btrfs_extent_data_ref *dref = NULL;
1830         struct btrfs_shared_data_ref *sref = NULL;
1831         unsigned long ptr;
1832         unsigned long end;
1833         u32 item_size;
1834         int size;
1835         int type;
1836         u64 refs;
1837
1838         leaf = path->nodes[0];
1839         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1840         refs = btrfs_extent_refs(leaf, ei);
1841         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1842         refs += refs_to_mod;
1843         btrfs_set_extent_refs(leaf, ei, refs);
1844         if (extent_op)
1845                 __run_delayed_extent_op(extent_op, leaf, ei);
1846
1847         type = btrfs_extent_inline_ref_type(leaf, iref);
1848
1849         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1850                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1851                 refs = btrfs_extent_data_ref_count(leaf, dref);
1852         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1853                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1854                 refs = btrfs_shared_data_ref_count(leaf, sref);
1855         } else {
1856                 refs = 1;
1857                 BUG_ON(refs_to_mod != -1);
1858         }
1859
1860         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1861         refs += refs_to_mod;
1862
1863         if (refs > 0) {
1864                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1865                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1866                 else
1867                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1868         } else {
1869                 *last_ref = 1;
1870                 size =  btrfs_extent_inline_ref_size(type);
1871                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1872                 ptr = (unsigned long)iref;
1873                 end = (unsigned long)ei + item_size;
1874                 if (ptr + size < end)
1875                         memmove_extent_buffer(leaf, ptr, ptr + size,
1876                                               end - ptr - size);
1877                 item_size -= size;
1878                 btrfs_truncate_item(root, path, item_size, 1);
1879         }
1880         btrfs_mark_buffer_dirty(leaf);
1881 }
1882
1883 static noinline_for_stack
1884 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1885                                  struct btrfs_root *root,
1886                                  struct btrfs_path *path,
1887                                  u64 bytenr, u64 num_bytes, u64 parent,
1888                                  u64 root_objectid, u64 owner,
1889                                  u64 offset, int refs_to_add,
1890                                  struct btrfs_delayed_extent_op *extent_op)
1891 {
1892         struct btrfs_extent_inline_ref *iref;
1893         int ret;
1894
1895         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1896                                            bytenr, num_bytes, parent,
1897                                            root_objectid, owner, offset, 1);
1898         if (ret == 0) {
1899                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1900                 update_inline_extent_backref(root, path, iref,
1901                                              refs_to_add, extent_op, NULL);
1902         } else if (ret == -ENOENT) {
1903                 setup_inline_extent_backref(root, path, iref, parent,
1904                                             root_objectid, owner, offset,
1905                                             refs_to_add, extent_op);
1906                 ret = 0;
1907         }
1908         return ret;
1909 }
1910
1911 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1912                                  struct btrfs_root *root,
1913                                  struct btrfs_path *path,
1914                                  u64 bytenr, u64 parent, u64 root_objectid,
1915                                  u64 owner, u64 offset, int refs_to_add)
1916 {
1917         int ret;
1918         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1919                 BUG_ON(refs_to_add != 1);
1920                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1921                                             parent, root_objectid);
1922         } else {
1923                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1924                                              parent, root_objectid,
1925                                              owner, offset, refs_to_add);
1926         }
1927         return ret;
1928 }
1929
1930 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1931                                  struct btrfs_root *root,
1932                                  struct btrfs_path *path,
1933                                  struct btrfs_extent_inline_ref *iref,
1934                                  int refs_to_drop, int is_data, int *last_ref)
1935 {
1936         int ret = 0;
1937
1938         BUG_ON(!is_data && refs_to_drop != 1);
1939         if (iref) {
1940                 update_inline_extent_backref(root, path, iref,
1941                                              -refs_to_drop, NULL, last_ref);
1942         } else if (is_data) {
1943                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1944                                              last_ref);
1945         } else {
1946                 *last_ref = 1;
1947                 ret = btrfs_del_item(trans, root, path);
1948         }
1949         return ret;
1950 }
1951
1952 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
1953 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1954                                u64 *discarded_bytes)
1955 {
1956         int j, ret = 0;
1957         u64 bytes_left, end;
1958         u64 aligned_start = ALIGN(start, 1 << 9);
1959
1960         if (WARN_ON(start != aligned_start)) {
1961                 len -= aligned_start - start;
1962                 len = round_down(len, 1 << 9);
1963                 start = aligned_start;
1964         }
1965
1966         *discarded_bytes = 0;
1967
1968         if (!len)
1969                 return 0;
1970
1971         end = start + len;
1972         bytes_left = len;
1973
1974         /* Skip any superblocks on this device. */
1975         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1976                 u64 sb_start = btrfs_sb_offset(j);
1977                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1978                 u64 size = sb_start - start;
1979
1980                 if (!in_range(sb_start, start, bytes_left) &&
1981                     !in_range(sb_end, start, bytes_left) &&
1982                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1983                         continue;
1984
1985                 /*
1986                  * Superblock spans beginning of range.  Adjust start and
1987                  * try again.
1988                  */
1989                 if (sb_start <= start) {
1990                         start += sb_end - start;
1991                         if (start > end) {
1992                                 bytes_left = 0;
1993                                 break;
1994                         }
1995                         bytes_left = end - start;
1996                         continue;
1997                 }
1998
1999                 if (size) {
2000                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2001                                                    GFP_NOFS, 0);
2002                         if (!ret)
2003                                 *discarded_bytes += size;
2004                         else if (ret != -EOPNOTSUPP)
2005                                 return ret;
2006                 }
2007
2008                 start = sb_end;
2009                 if (start > end) {
2010                         bytes_left = 0;
2011                         break;
2012                 }
2013                 bytes_left = end - start;
2014         }
2015
2016         if (bytes_left) {
2017                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2018                                            GFP_NOFS, 0);
2019                 if (!ret)
2020                         *discarded_bytes += bytes_left;
2021         }
2022         return ret;
2023 }
2024
2025 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
2026                          u64 num_bytes, u64 *actual_bytes)
2027 {
2028         int ret;
2029         u64 discarded_bytes = 0;
2030         struct btrfs_bio *bbio = NULL;
2031
2032
2033         /*
2034          * Avoid races with device replace and make sure our bbio has devices
2035          * associated to its stripes that don't go away while we are discarding.
2036          */
2037         btrfs_bio_counter_inc_blocked(root->fs_info);
2038         /* Tell the block device(s) that the sectors can be discarded */
2039         ret = btrfs_map_block(root->fs_info, REQ_OP_DISCARD,
2040                               bytenr, &num_bytes, &bbio, 0);
2041         /* Error condition is -ENOMEM */
2042         if (!ret) {
2043                 struct btrfs_bio_stripe *stripe = bbio->stripes;
2044                 int i;
2045
2046
2047                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2048                         u64 bytes;
2049                         if (!stripe->dev->can_discard)
2050                                 continue;
2051
2052                         ret = btrfs_issue_discard(stripe->dev->bdev,
2053                                                   stripe->physical,
2054                                                   stripe->length,
2055                                                   &bytes);
2056                         if (!ret)
2057                                 discarded_bytes += bytes;
2058                         else if (ret != -EOPNOTSUPP)
2059                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2060
2061                         /*
2062                          * Just in case we get back EOPNOTSUPP for some reason,
2063                          * just ignore the return value so we don't screw up
2064                          * people calling discard_extent.
2065                          */
2066                         ret = 0;
2067                 }
2068                 btrfs_put_bbio(bbio);
2069         }
2070         btrfs_bio_counter_dec(root->fs_info);
2071
2072         if (actual_bytes)
2073                 *actual_bytes = discarded_bytes;
2074
2075
2076         if (ret == -EOPNOTSUPP)
2077                 ret = 0;
2078         return ret;
2079 }
2080
2081 /* Can return -ENOMEM */
2082 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2083                          struct btrfs_root *root,
2084                          u64 bytenr, u64 num_bytes, u64 parent,
2085                          u64 root_objectid, u64 owner, u64 offset)
2086 {
2087         int ret;
2088         struct btrfs_fs_info *fs_info = root->fs_info;
2089
2090         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2091                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2092
2093         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2094                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2095                                         num_bytes,
2096                                         parent, root_objectid, (int)owner,
2097                                         BTRFS_ADD_DELAYED_REF, NULL);
2098         } else {
2099                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2100                                         num_bytes, parent, root_objectid,
2101                                         owner, offset, 0,
2102                                         BTRFS_ADD_DELAYED_REF, NULL);
2103         }
2104         return ret;
2105 }
2106
2107 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2108                                   struct btrfs_root *root,
2109                                   struct btrfs_delayed_ref_node *node,
2110                                   u64 parent, u64 root_objectid,
2111                                   u64 owner, u64 offset, int refs_to_add,
2112                                   struct btrfs_delayed_extent_op *extent_op)
2113 {
2114         struct btrfs_fs_info *fs_info = root->fs_info;
2115         struct btrfs_path *path;
2116         struct extent_buffer *leaf;
2117         struct btrfs_extent_item *item;
2118         struct btrfs_key key;
2119         u64 bytenr = node->bytenr;
2120         u64 num_bytes = node->num_bytes;
2121         u64 refs;
2122         int ret;
2123
2124         path = btrfs_alloc_path();
2125         if (!path)
2126                 return -ENOMEM;
2127
2128         path->reada = READA_FORWARD;
2129         path->leave_spinning = 1;
2130         /* this will setup the path even if it fails to insert the back ref */
2131         ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
2132                                            bytenr, num_bytes, parent,
2133                                            root_objectid, owner, offset,
2134                                            refs_to_add, extent_op);
2135         if ((ret < 0 && ret != -EAGAIN) || !ret)
2136                 goto out;
2137
2138         /*
2139          * Ok we had -EAGAIN which means we didn't have space to insert and
2140          * inline extent ref, so just update the reference count and add a
2141          * normal backref.
2142          */
2143         leaf = path->nodes[0];
2144         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2145         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2146         refs = btrfs_extent_refs(leaf, item);
2147         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2148         if (extent_op)
2149                 __run_delayed_extent_op(extent_op, leaf, item);
2150
2151         btrfs_mark_buffer_dirty(leaf);
2152         btrfs_release_path(path);
2153
2154         path->reada = READA_FORWARD;
2155         path->leave_spinning = 1;
2156         /* now insert the actual backref */
2157         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2158                                     path, bytenr, parent, root_objectid,
2159                                     owner, offset, refs_to_add);
2160         if (ret)
2161                 btrfs_abort_transaction(trans, ret);
2162 out:
2163         btrfs_free_path(path);
2164         return ret;
2165 }
2166
2167 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2168                                 struct btrfs_root *root,
2169                                 struct btrfs_delayed_ref_node *node,
2170                                 struct btrfs_delayed_extent_op *extent_op,
2171                                 int insert_reserved)
2172 {
2173         int ret = 0;
2174         struct btrfs_delayed_data_ref *ref;
2175         struct btrfs_key ins;
2176         u64 parent = 0;
2177         u64 ref_root = 0;
2178         u64 flags = 0;
2179
2180         ins.objectid = node->bytenr;
2181         ins.offset = node->num_bytes;
2182         ins.type = BTRFS_EXTENT_ITEM_KEY;
2183
2184         ref = btrfs_delayed_node_to_data_ref(node);
2185         trace_run_delayed_data_ref(root->fs_info, node, ref, node->action);
2186
2187         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2188                 parent = ref->parent;
2189         ref_root = ref->root;
2190
2191         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2192                 if (extent_op)
2193                         flags |= extent_op->flags_to_set;
2194                 ret = alloc_reserved_file_extent(trans, root,
2195                                                  parent, ref_root, flags,
2196                                                  ref->objectid, ref->offset,
2197                                                  &ins, node->ref_mod);
2198         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2199                 ret = __btrfs_inc_extent_ref(trans, root, node, parent,
2200                                              ref_root, ref->objectid,
2201                                              ref->offset, node->ref_mod,
2202                                              extent_op);
2203         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2204                 ret = __btrfs_free_extent(trans, root, node, parent,
2205                                           ref_root, ref->objectid,
2206                                           ref->offset, node->ref_mod,
2207                                           extent_op);
2208         } else {
2209                 BUG();
2210         }
2211         return ret;
2212 }
2213
2214 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2215                                     struct extent_buffer *leaf,
2216                                     struct btrfs_extent_item *ei)
2217 {
2218         u64 flags = btrfs_extent_flags(leaf, ei);
2219         if (extent_op->update_flags) {
2220                 flags |= extent_op->flags_to_set;
2221                 btrfs_set_extent_flags(leaf, ei, flags);
2222         }
2223
2224         if (extent_op->update_key) {
2225                 struct btrfs_tree_block_info *bi;
2226                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2227                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2228                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2229         }
2230 }
2231
2232 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2233                                  struct btrfs_root *root,
2234                                  struct btrfs_delayed_ref_node *node,
2235                                  struct btrfs_delayed_extent_op *extent_op)
2236 {
2237         struct btrfs_key key;
2238         struct btrfs_path *path;
2239         struct btrfs_extent_item *ei;
2240         struct extent_buffer *leaf;
2241         u32 item_size;
2242         int ret;
2243         int err = 0;
2244         int metadata = !extent_op->is_data;
2245
2246         if (trans->aborted)
2247                 return 0;
2248
2249         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2250                 metadata = 0;
2251
2252         path = btrfs_alloc_path();
2253         if (!path)
2254                 return -ENOMEM;
2255
2256         key.objectid = node->bytenr;
2257
2258         if (metadata) {
2259                 key.type = BTRFS_METADATA_ITEM_KEY;
2260                 key.offset = extent_op->level;
2261         } else {
2262                 key.type = BTRFS_EXTENT_ITEM_KEY;
2263                 key.offset = node->num_bytes;
2264         }
2265
2266 again:
2267         path->reada = READA_FORWARD;
2268         path->leave_spinning = 1;
2269         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2270                                 path, 0, 1);
2271         if (ret < 0) {
2272                 err = ret;
2273                 goto out;
2274         }
2275         if (ret > 0) {
2276                 if (metadata) {
2277                         if (path->slots[0] > 0) {
2278                                 path->slots[0]--;
2279                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2280                                                       path->slots[0]);
2281                                 if (key.objectid == node->bytenr &&
2282                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2283                                     key.offset == node->num_bytes)
2284                                         ret = 0;
2285                         }
2286                         if (ret > 0) {
2287                                 btrfs_release_path(path);
2288                                 metadata = 0;
2289
2290                                 key.objectid = node->bytenr;
2291                                 key.offset = node->num_bytes;
2292                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2293                                 goto again;
2294                         }
2295                 } else {
2296                         err = -EIO;
2297                         goto out;
2298                 }
2299         }
2300
2301         leaf = path->nodes[0];
2302         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2303 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2304         if (item_size < sizeof(*ei)) {
2305                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2306                                              path, (u64)-1, 0);
2307                 if (ret < 0) {
2308                         err = ret;
2309                         goto out;
2310                 }
2311                 leaf = path->nodes[0];
2312                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2313         }
2314 #endif
2315         BUG_ON(item_size < sizeof(*ei));
2316         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2317         __run_delayed_extent_op(extent_op, leaf, ei);
2318
2319         btrfs_mark_buffer_dirty(leaf);
2320 out:
2321         btrfs_free_path(path);
2322         return err;
2323 }
2324
2325 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2326                                 struct btrfs_root *root,
2327                                 struct btrfs_delayed_ref_node *node,
2328                                 struct btrfs_delayed_extent_op *extent_op,
2329                                 int insert_reserved)
2330 {
2331         int ret = 0;
2332         struct btrfs_delayed_tree_ref *ref;
2333         struct btrfs_key ins;
2334         u64 parent = 0;
2335         u64 ref_root = 0;
2336         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2337                                                  SKINNY_METADATA);
2338
2339         ref = btrfs_delayed_node_to_tree_ref(node);
2340         trace_run_delayed_tree_ref(root->fs_info, node, ref, node->action);
2341
2342         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2343                 parent = ref->parent;
2344         ref_root = ref->root;
2345
2346         ins.objectid = node->bytenr;
2347         if (skinny_metadata) {
2348                 ins.offset = ref->level;
2349                 ins.type = BTRFS_METADATA_ITEM_KEY;
2350         } else {
2351                 ins.offset = node->num_bytes;
2352                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2353         }
2354
2355         BUG_ON(node->ref_mod != 1);
2356         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2357                 BUG_ON(!extent_op || !extent_op->update_flags);
2358                 ret = alloc_reserved_tree_block(trans, root,
2359                                                 parent, ref_root,
2360                                                 extent_op->flags_to_set,
2361                                                 &extent_op->key,
2362                                                 ref->level, &ins);
2363         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2364                 ret = __btrfs_inc_extent_ref(trans, root, node,
2365                                              parent, ref_root,
2366                                              ref->level, 0, 1,
2367                                              extent_op);
2368         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2369                 ret = __btrfs_free_extent(trans, root, node,
2370                                           parent, ref_root,
2371                                           ref->level, 0, 1, extent_op);
2372         } else {
2373                 BUG();
2374         }
2375         return ret;
2376 }
2377
2378 /* helper function to actually process a single delayed ref entry */
2379 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2380                                struct btrfs_root *root,
2381                                struct btrfs_delayed_ref_node *node,
2382                                struct btrfs_delayed_extent_op *extent_op,
2383                                int insert_reserved)
2384 {
2385         int ret = 0;
2386
2387         if (trans->aborted) {
2388                 if (insert_reserved)
2389                         btrfs_pin_extent(root, node->bytenr,
2390                                          node->num_bytes, 1);
2391                 return 0;
2392         }
2393
2394         if (btrfs_delayed_ref_is_head(node)) {
2395                 struct btrfs_delayed_ref_head *head;
2396                 /*
2397                  * we've hit the end of the chain and we were supposed
2398                  * to insert this extent into the tree.  But, it got
2399                  * deleted before we ever needed to insert it, so all
2400                  * we have to do is clean up the accounting
2401                  */
2402                 BUG_ON(extent_op);
2403                 head = btrfs_delayed_node_to_head(node);
2404                 trace_run_delayed_ref_head(root->fs_info, node, head,
2405                                            node->action);
2406
2407                 if (insert_reserved) {
2408                         btrfs_pin_extent(root, node->bytenr,
2409                                          node->num_bytes, 1);
2410                         if (head->is_data) {
2411                                 ret = btrfs_del_csums(trans, root,
2412                                                       node->bytenr,
2413                                                       node->num_bytes);
2414                         }
2415                 }
2416
2417                 /* Also free its reserved qgroup space */
2418                 btrfs_qgroup_free_delayed_ref(root->fs_info,
2419                                               head->qgroup_ref_root,
2420                                               head->qgroup_reserved);
2421                 return ret;
2422         }
2423
2424         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2425             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2426                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2427                                            insert_reserved);
2428         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2429                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2430                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2431                                            insert_reserved);
2432         else
2433                 BUG();
2434         return ret;
2435 }
2436
2437 static inline struct btrfs_delayed_ref_node *
2438 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2439 {
2440         struct btrfs_delayed_ref_node *ref;
2441
2442         if (list_empty(&head->ref_list))
2443                 return NULL;
2444
2445         /*
2446          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2447          * This is to prevent a ref count from going down to zero, which deletes
2448          * the extent item from the extent tree, when there still are references
2449          * to add, which would fail because they would not find the extent item.
2450          */
2451         list_for_each_entry(ref, &head->ref_list, list) {
2452                 if (ref->action == BTRFS_ADD_DELAYED_REF)
2453                         return ref;
2454         }
2455
2456         return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
2457                           list);
2458 }
2459
2460 /*
2461  * Returns 0 on success or if called with an already aborted transaction.
2462  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2463  */
2464 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2465                                              struct btrfs_root *root,
2466                                              unsigned long nr)
2467 {
2468         struct btrfs_delayed_ref_root *delayed_refs;
2469         struct btrfs_delayed_ref_node *ref;
2470         struct btrfs_delayed_ref_head *locked_ref = NULL;
2471         struct btrfs_delayed_extent_op *extent_op;
2472         struct btrfs_fs_info *fs_info = root->fs_info;
2473         ktime_t start = ktime_get();
2474         int ret;
2475         unsigned long count = 0;
2476         unsigned long actual_count = 0;
2477         int must_insert_reserved = 0;
2478
2479         delayed_refs = &trans->transaction->delayed_refs;
2480         while (1) {
2481                 if (!locked_ref) {
2482                         if (count >= nr)
2483                                 break;
2484
2485                         spin_lock(&delayed_refs->lock);
2486                         locked_ref = btrfs_select_ref_head(trans);
2487                         if (!locked_ref) {
2488                                 spin_unlock(&delayed_refs->lock);
2489                                 break;
2490                         }
2491
2492                         /* grab the lock that says we are going to process
2493                          * all the refs for this head */
2494                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2495                         spin_unlock(&delayed_refs->lock);
2496                         /*
2497                          * we may have dropped the spin lock to get the head
2498                          * mutex lock, and that might have given someone else
2499                          * time to free the head.  If that's true, it has been
2500                          * removed from our list and we can move on.
2501                          */
2502                         if (ret == -EAGAIN) {
2503                                 locked_ref = NULL;
2504                                 count++;
2505                                 continue;
2506                         }
2507                 }
2508
2509                 /*
2510                  * We need to try and merge add/drops of the same ref since we
2511                  * can run into issues with relocate dropping the implicit ref
2512                  * and then it being added back again before the drop can
2513                  * finish.  If we merged anything we need to re-loop so we can
2514                  * get a good ref.
2515                  * Or we can get node references of the same type that weren't
2516                  * merged when created due to bumps in the tree mod seq, and
2517                  * we need to merge them to prevent adding an inline extent
2518                  * backref before dropping it (triggering a BUG_ON at
2519                  * insert_inline_extent_backref()).
2520                  */
2521                 spin_lock(&locked_ref->lock);
2522                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2523                                          locked_ref);
2524
2525                 /*
2526                  * locked_ref is the head node, so we have to go one
2527                  * node back for any delayed ref updates
2528                  */
2529                 ref = select_delayed_ref(locked_ref);
2530
2531                 if (ref && ref->seq &&
2532                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2533                         spin_unlock(&locked_ref->lock);
2534                         btrfs_delayed_ref_unlock(locked_ref);
2535                         spin_lock(&delayed_refs->lock);
2536                         locked_ref->processing = 0;
2537                         delayed_refs->num_heads_ready++;
2538                         spin_unlock(&delayed_refs->lock);
2539                         locked_ref = NULL;
2540                         cond_resched();
2541                         count++;
2542                         continue;
2543                 }
2544
2545                 /*
2546                  * record the must insert reserved flag before we
2547                  * drop the spin lock.
2548                  */
2549                 must_insert_reserved = locked_ref->must_insert_reserved;
2550                 locked_ref->must_insert_reserved = 0;
2551
2552                 extent_op = locked_ref->extent_op;
2553                 locked_ref->extent_op = NULL;
2554
2555                 if (!ref) {
2556
2557
2558                         /* All delayed refs have been processed, Go ahead
2559                          * and send the head node to run_one_delayed_ref,
2560                          * so that any accounting fixes can happen
2561                          */
2562                         ref = &locked_ref->node;
2563
2564                         if (extent_op && must_insert_reserved) {
2565                                 btrfs_free_delayed_extent_op(extent_op);
2566                                 extent_op = NULL;
2567                         }
2568
2569                         if (extent_op) {
2570                                 spin_unlock(&locked_ref->lock);
2571                                 ret = run_delayed_extent_op(trans, root,
2572                                                             ref, extent_op);
2573                                 btrfs_free_delayed_extent_op(extent_op);
2574
2575                                 if (ret) {
2576                                         /*
2577                                          * Need to reset must_insert_reserved if
2578                                          * there was an error so the abort stuff
2579                                          * can cleanup the reserved space
2580                                          * properly.
2581                                          */
2582                                         if (must_insert_reserved)
2583                                                 locked_ref->must_insert_reserved = 1;
2584                                         locked_ref->processing = 0;
2585                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2586                                         btrfs_delayed_ref_unlock(locked_ref);
2587                                         return ret;
2588                                 }
2589                                 continue;
2590                         }
2591
2592                         /*
2593                          * Need to drop our head ref lock and re-acquire the
2594                          * delayed ref lock and then re-check to make sure
2595                          * nobody got added.
2596                          */
2597                         spin_unlock(&locked_ref->lock);
2598                         spin_lock(&delayed_refs->lock);
2599                         spin_lock(&locked_ref->lock);
2600                         if (!list_empty(&locked_ref->ref_list) ||
2601                             locked_ref->extent_op) {
2602                                 spin_unlock(&locked_ref->lock);
2603                                 spin_unlock(&delayed_refs->lock);
2604                                 continue;
2605                         }
2606                         ref->in_tree = 0;
2607                         delayed_refs->num_heads--;
2608                         rb_erase(&locked_ref->href_node,
2609                                  &delayed_refs->href_root);
2610                         spin_unlock(&delayed_refs->lock);
2611                 } else {
2612                         actual_count++;
2613                         ref->in_tree = 0;
2614                         list_del(&ref->list);
2615                 }
2616                 atomic_dec(&delayed_refs->num_entries);
2617
2618                 if (!btrfs_delayed_ref_is_head(ref)) {
2619                         /*
2620                          * when we play the delayed ref, also correct the
2621                          * ref_mod on head
2622                          */
2623                         switch (ref->action) {
2624                         case BTRFS_ADD_DELAYED_REF:
2625                         case BTRFS_ADD_DELAYED_EXTENT:
2626                                 locked_ref->node.ref_mod -= ref->ref_mod;
2627                                 break;
2628                         case BTRFS_DROP_DELAYED_REF:
2629                                 locked_ref->node.ref_mod += ref->ref_mod;
2630                                 break;
2631                         default:
2632                                 WARN_ON(1);
2633                         }
2634                 }
2635                 spin_unlock(&locked_ref->lock);
2636
2637                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2638                                           must_insert_reserved);
2639
2640                 btrfs_free_delayed_extent_op(extent_op);
2641                 if (ret) {
2642                         locked_ref->processing = 0;
2643                         btrfs_delayed_ref_unlock(locked_ref);
2644                         btrfs_put_delayed_ref(ref);
2645                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2646                         return ret;
2647                 }
2648
2649                 /*
2650                  * If this node is a head, that means all the refs in this head
2651                  * have been dealt with, and we will pick the next head to deal
2652                  * with, so we must unlock the head and drop it from the cluster
2653                  * list before we release it.
2654                  */
2655                 if (btrfs_delayed_ref_is_head(ref)) {
2656                         if (locked_ref->is_data &&
2657                             locked_ref->total_ref_mod < 0) {
2658                                 spin_lock(&delayed_refs->lock);
2659                                 delayed_refs->pending_csums -= ref->num_bytes;
2660                                 spin_unlock(&delayed_refs->lock);
2661                         }
2662                         btrfs_delayed_ref_unlock(locked_ref);
2663                         locked_ref = NULL;
2664                 }
2665                 btrfs_put_delayed_ref(ref);
2666                 count++;
2667                 cond_resched();
2668         }
2669
2670         /*
2671          * We don't want to include ref heads since we can have empty ref heads
2672          * and those will drastically skew our runtime down since we just do
2673          * accounting, no actual extent tree updates.
2674          */
2675         if (actual_count > 0) {
2676                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2677                 u64 avg;
2678
2679                 /*
2680                  * We weigh the current average higher than our current runtime
2681                  * to avoid large swings in the average.
2682                  */
2683                 spin_lock(&delayed_refs->lock);
2684                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2685                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2686                 spin_unlock(&delayed_refs->lock);
2687         }
2688         return 0;
2689 }
2690
2691 #ifdef SCRAMBLE_DELAYED_REFS
2692 /*
2693  * Normally delayed refs get processed in ascending bytenr order. This
2694  * correlates in most cases to the order added. To expose dependencies on this
2695  * order, we start to process the tree in the middle instead of the beginning
2696  */
2697 static u64 find_middle(struct rb_root *root)
2698 {
2699         struct rb_node *n = root->rb_node;
2700         struct btrfs_delayed_ref_node *entry;
2701         int alt = 1;
2702         u64 middle;
2703         u64 first = 0, last = 0;
2704
2705         n = rb_first(root);
2706         if (n) {
2707                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2708                 first = entry->bytenr;
2709         }
2710         n = rb_last(root);
2711         if (n) {
2712                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2713                 last = entry->bytenr;
2714         }
2715         n = root->rb_node;
2716
2717         while (n) {
2718                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2719                 WARN_ON(!entry->in_tree);
2720
2721                 middle = entry->bytenr;
2722
2723                 if (alt)
2724                         n = n->rb_left;
2725                 else
2726                         n = n->rb_right;
2727
2728                 alt = 1 - alt;
2729         }
2730         return middle;
2731 }
2732 #endif
2733
2734 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2735 {
2736         u64 num_bytes;
2737
2738         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2739                              sizeof(struct btrfs_extent_inline_ref));
2740         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2741                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2742
2743         /*
2744          * We don't ever fill up leaves all the way so multiply by 2 just to be
2745          * closer to what we're really going to want to use.
2746          */
2747         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2748 }
2749
2750 /*
2751  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2752  * would require to store the csums for that many bytes.
2753  */
2754 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2755 {
2756         u64 csum_size;
2757         u64 num_csums_per_leaf;
2758         u64 num_csums;
2759
2760         csum_size = BTRFS_MAX_ITEM_SIZE(root);
2761         num_csums_per_leaf = div64_u64(csum_size,
2762                         (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2763         num_csums = div64_u64(csum_bytes, root->sectorsize);
2764         num_csums += num_csums_per_leaf - 1;
2765         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2766         return num_csums;
2767 }
2768
2769 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2770                                        struct btrfs_root *root)
2771 {
2772         struct btrfs_block_rsv *global_rsv;
2773         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2774         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2775         u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2776         u64 num_bytes, num_dirty_bgs_bytes;
2777         int ret = 0;
2778
2779         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2780         num_heads = heads_to_leaves(root, num_heads);
2781         if (num_heads > 1)
2782                 num_bytes += (num_heads - 1) * root->nodesize;
2783         num_bytes <<= 1;
2784         num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2785         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2786                                                              num_dirty_bgs);
2787         global_rsv = &root->fs_info->global_block_rsv;
2788
2789         /*
2790          * If we can't allocate any more chunks lets make sure we have _lots_ of
2791          * wiggle room since running delayed refs can create more delayed refs.
2792          */
2793         if (global_rsv->space_info->full) {
2794                 num_dirty_bgs_bytes <<= 1;
2795                 num_bytes <<= 1;
2796         }
2797
2798         spin_lock(&global_rsv->lock);
2799         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2800                 ret = 1;
2801         spin_unlock(&global_rsv->lock);
2802         return ret;
2803 }
2804
2805 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2806                                        struct btrfs_root *root)
2807 {
2808         struct btrfs_fs_info *fs_info = root->fs_info;
2809         u64 num_entries =
2810                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2811         u64 avg_runtime;
2812         u64 val;
2813
2814         smp_mb();
2815         avg_runtime = fs_info->avg_delayed_ref_runtime;
2816         val = num_entries * avg_runtime;
2817         if (num_entries * avg_runtime >= NSEC_PER_SEC)
2818                 return 1;
2819         if (val >= NSEC_PER_SEC / 2)
2820                 return 2;
2821
2822         return btrfs_check_space_for_delayed_refs(trans, root);
2823 }
2824
2825 struct async_delayed_refs {
2826         struct btrfs_root *root;
2827         u64 transid;
2828         int count;
2829         int error;
2830         int sync;
2831         struct completion wait;
2832         struct btrfs_work work;
2833 };
2834
2835 static void delayed_ref_async_start(struct btrfs_work *work)
2836 {
2837         struct async_delayed_refs *async;
2838         struct btrfs_trans_handle *trans;
2839         int ret;
2840
2841         async = container_of(work, struct async_delayed_refs, work);
2842
2843         /* if the commit is already started, we don't need to wait here */
2844         if (btrfs_transaction_blocked(async->root->fs_info))
2845                 goto done;
2846
2847         trans = btrfs_join_transaction(async->root);
2848         if (IS_ERR(trans)) {
2849                 async->error = PTR_ERR(trans);
2850                 goto done;
2851         }
2852
2853         /*
2854          * trans->sync means that when we call end_transaction, we won't
2855          * wait on delayed refs
2856          */
2857         trans->sync = true;
2858
2859         /* Don't bother flushing if we got into a different transaction */
2860         if (trans->transid > async->transid)
2861                 goto end;
2862
2863         ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2864         if (ret)
2865                 async->error = ret;
2866 end:
2867         ret = btrfs_end_transaction(trans, async->root);
2868         if (ret && !async->error)
2869                 async->error = ret;
2870 done:
2871         if (async->sync)
2872                 complete(&async->wait);
2873         else
2874                 kfree(async);
2875 }
2876
2877 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2878                                  unsigned long count, u64 transid, int wait)
2879 {
2880         struct async_delayed_refs *async;
2881         int ret;
2882
2883         async = kmalloc(sizeof(*async), GFP_NOFS);
2884         if (!async)
2885                 return -ENOMEM;
2886
2887         async->root = root->fs_info->tree_root;
2888         async->count = count;
2889         async->error = 0;
2890         async->transid = transid;
2891         if (wait)
2892                 async->sync = 1;
2893         else
2894                 async->sync = 0;
2895         init_completion(&async->wait);
2896
2897         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2898                         delayed_ref_async_start, NULL, NULL);
2899
2900         btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2901
2902         if (wait) {
2903                 wait_for_completion(&async->wait);
2904                 ret = async->error;
2905                 kfree(async);
2906                 return ret;
2907         }
2908         return 0;
2909 }
2910
2911 /*
2912  * this starts processing the delayed reference count updates and
2913  * extent insertions we have queued up so far.  count can be
2914  * 0, which means to process everything in the tree at the start
2915  * of the run (but not newly added entries), or it can be some target
2916  * number you'd like to process.
2917  *
2918  * Returns 0 on success or if called with an aborted transaction
2919  * Returns <0 on error and aborts the transaction
2920  */
2921 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2922                            struct btrfs_root *root, unsigned long count)
2923 {
2924         struct rb_node *node;
2925         struct btrfs_delayed_ref_root *delayed_refs;
2926         struct btrfs_delayed_ref_head *head;
2927         int ret;
2928         int run_all = count == (unsigned long)-1;
2929         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2930
2931         /* We'll clean this up in btrfs_cleanup_transaction */
2932         if (trans->aborted)
2933                 return 0;
2934
2935         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &root->fs_info->flags))
2936                 return 0;
2937
2938         if (root == root->fs_info->extent_root)
2939                 root = root->fs_info->tree_root;
2940
2941         delayed_refs = &trans->transaction->delayed_refs;
2942         if (count == 0)
2943                 count = atomic_read(&delayed_refs->num_entries) * 2;
2944
2945 again:
2946 #ifdef SCRAMBLE_DELAYED_REFS
2947         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2948 #endif
2949         trans->can_flush_pending_bgs = false;
2950         ret = __btrfs_run_delayed_refs(trans, root, count);
2951         if (ret < 0) {
2952                 btrfs_abort_transaction(trans, ret);
2953                 return ret;
2954         }
2955
2956         if (run_all) {
2957                 if (!list_empty(&trans->new_bgs))
2958                         btrfs_create_pending_block_groups(trans, root);
2959
2960                 spin_lock(&delayed_refs->lock);
2961                 node = rb_first(&delayed_refs->href_root);
2962                 if (!node) {
2963                         spin_unlock(&delayed_refs->lock);
2964                         goto out;
2965                 }
2966                 count = (unsigned long)-1;
2967
2968                 while (node) {
2969                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2970                                         href_node);
2971                         if (btrfs_delayed_ref_is_head(&head->node)) {
2972                                 struct btrfs_delayed_ref_node *ref;
2973
2974                                 ref = &head->node;
2975                                 atomic_inc(&ref->refs);
2976
2977                                 spin_unlock(&delayed_refs->lock);
2978                                 /*
2979                                  * Mutex was contended, block until it's
2980                                  * released and try again
2981                                  */
2982                                 mutex_lock(&head->mutex);
2983                                 mutex_unlock(&head->mutex);
2984
2985                                 btrfs_put_delayed_ref(ref);
2986                                 cond_resched();
2987                                 goto again;
2988                         } else {
2989                                 WARN_ON(1);
2990                         }
2991                         node = rb_next(node);
2992                 }
2993                 spin_unlock(&delayed_refs->lock);
2994                 cond_resched();
2995                 goto again;
2996         }
2997 out:
2998         assert_qgroups_uptodate(trans);
2999         trans->can_flush_pending_bgs = can_flush_pending_bgs;
3000         return 0;
3001 }
3002
3003 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3004                                 struct btrfs_root *root,
3005                                 u64 bytenr, u64 num_bytes, u64 flags,
3006                                 int level, int is_data)
3007 {
3008         struct btrfs_delayed_extent_op *extent_op;
3009         int ret;
3010
3011         extent_op = btrfs_alloc_delayed_extent_op();
3012         if (!extent_op)
3013                 return -ENOMEM;
3014
3015         extent_op->flags_to_set = flags;
3016         extent_op->update_flags = true;
3017         extent_op->update_key = false;
3018         extent_op->is_data = is_data ? true : false;
3019         extent_op->level = level;
3020
3021         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
3022                                           num_bytes, extent_op);
3023         if (ret)
3024                 btrfs_free_delayed_extent_op(extent_op);
3025         return ret;
3026 }
3027
3028 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
3029                                       struct btrfs_root *root,
3030                                       struct btrfs_path *path,
3031                                       u64 objectid, u64 offset, u64 bytenr)
3032 {
3033         struct btrfs_delayed_ref_head *head;
3034         struct btrfs_delayed_ref_node *ref;
3035         struct btrfs_delayed_data_ref *data_ref;
3036         struct btrfs_delayed_ref_root *delayed_refs;
3037         int ret = 0;
3038
3039         delayed_refs = &trans->transaction->delayed_refs;
3040         spin_lock(&delayed_refs->lock);
3041         head = btrfs_find_delayed_ref_head(trans, bytenr);
3042         if (!head) {
3043                 spin_unlock(&delayed_refs->lock);
3044                 return 0;
3045         }
3046
3047         if (!mutex_trylock(&head->mutex)) {
3048                 atomic_inc(&head->node.refs);
3049                 spin_unlock(&delayed_refs->lock);
3050
3051                 btrfs_release_path(path);
3052
3053                 /*
3054                  * Mutex was contended, block until it's released and let
3055                  * caller try again
3056                  */
3057                 mutex_lock(&head->mutex);
3058                 mutex_unlock(&head->mutex);
3059                 btrfs_put_delayed_ref(&head->node);
3060                 return -EAGAIN;
3061         }
3062         spin_unlock(&delayed_refs->lock);
3063
3064         spin_lock(&head->lock);
3065         list_for_each_entry(ref, &head->ref_list, list) {
3066                 /* If it's a shared ref we know a cross reference exists */
3067                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3068                         ret = 1;
3069                         break;
3070                 }
3071
3072                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3073
3074                 /*
3075                  * If our ref doesn't match the one we're currently looking at
3076                  * then we have a cross reference.
3077                  */
3078                 if (data_ref->root != root->root_key.objectid ||
3079                     data_ref->objectid != objectid ||
3080                     data_ref->offset != offset) {
3081                         ret = 1;
3082                         break;
3083                 }
3084         }
3085         spin_unlock(&head->lock);
3086         mutex_unlock(&head->mutex);
3087         return ret;
3088 }
3089
3090 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
3091                                         struct btrfs_root *root,
3092                                         struct btrfs_path *path,
3093                                         u64 objectid, u64 offset, u64 bytenr)
3094 {
3095         struct btrfs_root *extent_root = root->fs_info->extent_root;
3096         struct extent_buffer *leaf;
3097         struct btrfs_extent_data_ref *ref;
3098         struct btrfs_extent_inline_ref *iref;
3099         struct btrfs_extent_item *ei;
3100         struct btrfs_key key;
3101         u32 item_size;
3102         int ret;
3103
3104         key.objectid = bytenr;
3105         key.offset = (u64)-1;
3106         key.type = BTRFS_EXTENT_ITEM_KEY;
3107
3108         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3109         if (ret < 0)
3110                 goto out;
3111         BUG_ON(ret == 0); /* Corruption */
3112
3113         ret = -ENOENT;
3114         if (path->slots[0] == 0)
3115                 goto out;
3116
3117         path->slots[0]--;
3118         leaf = path->nodes[0];
3119         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3120
3121         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3122                 goto out;
3123
3124         ret = 1;
3125         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3126 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3127         if (item_size < sizeof(*ei)) {
3128                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3129                 goto out;
3130         }
3131 #endif
3132         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3133
3134         if (item_size != sizeof(*ei) +
3135             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3136                 goto out;
3137
3138         if (btrfs_extent_generation(leaf, ei) <=
3139             btrfs_root_last_snapshot(&root->root_item))
3140                 goto out;
3141
3142         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3143         if (btrfs_extent_inline_ref_type(leaf, iref) !=
3144             BTRFS_EXTENT_DATA_REF_KEY)
3145                 goto out;
3146
3147         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3148         if (btrfs_extent_refs(leaf, ei) !=
3149             btrfs_extent_data_ref_count(leaf, ref) ||
3150             btrfs_extent_data_ref_root(leaf, ref) !=
3151             root->root_key.objectid ||
3152             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3153             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3154                 goto out;
3155
3156         ret = 0;
3157 out:
3158         return ret;
3159 }
3160
3161 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3162                           struct btrfs_root *root,
3163                           u64 objectid, u64 offset, u64 bytenr)
3164 {
3165         struct btrfs_path *path;
3166         int ret;
3167         int ret2;
3168
3169         path = btrfs_alloc_path();
3170         if (!path)
3171                 return -ENOENT;
3172
3173         do {
3174                 ret = check_committed_ref(trans, root, path, objectid,
3175                                           offset, bytenr);
3176                 if (ret && ret != -ENOENT)
3177                         goto out;
3178
3179                 ret2 = check_delayed_ref(trans, root, path, objectid,
3180                                          offset, bytenr);
3181         } while (ret2 == -EAGAIN);
3182
3183         if (ret2 && ret2 != -ENOENT) {
3184                 ret = ret2;
3185                 goto out;
3186         }
3187
3188         if (ret != -ENOENT || ret2 != -ENOENT)
3189                 ret = 0;
3190 out:
3191         btrfs_free_path(path);
3192         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3193                 WARN_ON(ret > 0);
3194         return ret;
3195 }
3196
3197 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3198                            struct btrfs_root *root,
3199                            struct extent_buffer *buf,
3200                            int full_backref, int inc)
3201 {
3202         u64 bytenr;
3203         u64 num_bytes;
3204         u64 parent;
3205         u64 ref_root;
3206         u32 nritems;
3207         struct btrfs_key key;
3208         struct btrfs_file_extent_item *fi;
3209         int i;
3210         int level;
3211         int ret = 0;
3212         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3213                             u64, u64, u64, u64, u64, u64);
3214
3215
3216         if (btrfs_is_testing(root->fs_info))
3217                 return 0;
3218
3219         ref_root = btrfs_header_owner(buf);
3220         nritems = btrfs_header_nritems(buf);
3221         level = btrfs_header_level(buf);
3222
3223         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3224                 return 0;
3225
3226         if (inc)
3227                 process_func = btrfs_inc_extent_ref;
3228         else
3229                 process_func = btrfs_free_extent;
3230
3231         if (full_backref)
3232                 parent = buf->start;
3233         else
3234                 parent = 0;
3235
3236         for (i = 0; i < nritems; i++) {
3237                 if (level == 0) {
3238                         btrfs_item_key_to_cpu(buf, &key, i);
3239                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3240                                 continue;
3241                         fi = btrfs_item_ptr(buf, i,
3242                                             struct btrfs_file_extent_item);
3243                         if (btrfs_file_extent_type(buf, fi) ==
3244                             BTRFS_FILE_EXTENT_INLINE)
3245                                 continue;
3246                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3247                         if (bytenr == 0)
3248                                 continue;
3249
3250                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3251                         key.offset -= btrfs_file_extent_offset(buf, fi);
3252                         ret = process_func(trans, root, bytenr, num_bytes,
3253                                            parent, ref_root, key.objectid,
3254                                            key.offset);
3255                         if (ret)
3256                                 goto fail;
3257                 } else {
3258                         bytenr = btrfs_node_blockptr(buf, i);
3259                         num_bytes = root->nodesize;
3260                         ret = process_func(trans, root, bytenr, num_bytes,
3261                                            parent, ref_root, level - 1, 0);
3262                         if (ret)
3263                                 goto fail;
3264                 }
3265         }
3266         return 0;
3267 fail:
3268         return ret;
3269 }
3270
3271 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3272                   struct extent_buffer *buf, int full_backref)
3273 {
3274         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3275 }
3276
3277 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3278                   struct extent_buffer *buf, int full_backref)
3279 {
3280         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3281 }
3282
3283 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3284                                  struct btrfs_root *root,
3285                                  struct btrfs_path *path,
3286                                  struct btrfs_block_group_cache *cache)
3287 {
3288         int ret;
3289         struct btrfs_root *extent_root = root->fs_info->extent_root;
3290         unsigned long bi;
3291         struct extent_buffer *leaf;
3292
3293         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3294         if (ret) {
3295                 if (ret > 0)
3296                         ret = -ENOENT;
3297                 goto fail;
3298         }
3299
3300         leaf = path->nodes[0];
3301         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3302         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3303         btrfs_mark_buffer_dirty(leaf);
3304 fail:
3305         btrfs_release_path(path);
3306         return ret;
3307
3308 }
3309
3310 static struct btrfs_block_group_cache *
3311 next_block_group(struct btrfs_root *root,
3312                  struct btrfs_block_group_cache *cache)
3313 {
3314         struct rb_node *node;
3315
3316         spin_lock(&root->fs_info->block_group_cache_lock);
3317
3318         /* If our block group was removed, we need a full search. */
3319         if (RB_EMPTY_NODE(&cache->cache_node)) {
3320                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3321
3322                 spin_unlock(&root->fs_info->block_group_cache_lock);
3323                 btrfs_put_block_group(cache);
3324                 cache = btrfs_lookup_first_block_group(root->fs_info,
3325                                                        next_bytenr);
3326                 return cache;
3327         }
3328         node = rb_next(&cache->cache_node);
3329         btrfs_put_block_group(cache);
3330         if (node) {
3331                 cache = rb_entry(node, struct btrfs_block_group_cache,
3332                                  cache_node);
3333                 btrfs_get_block_group(cache);
3334         } else
3335                 cache = NULL;
3336         spin_unlock(&root->fs_info->block_group_cache_lock);
3337         return cache;
3338 }
3339
3340 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3341                             struct btrfs_trans_handle *trans,
3342                             struct btrfs_path *path)
3343 {
3344         struct btrfs_root *root = block_group->fs_info->tree_root;
3345         struct inode *inode = NULL;
3346         u64 alloc_hint = 0;
3347         int dcs = BTRFS_DC_ERROR;
3348         u64 num_pages = 0;
3349         int retries = 0;
3350         int ret = 0;
3351
3352         /*
3353          * If this block group is smaller than 100 megs don't bother caching the
3354          * block group.
3355          */
3356         if (block_group->key.offset < (100 * SZ_1M)) {
3357                 spin_lock(&block_group->lock);
3358                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3359                 spin_unlock(&block_group->lock);
3360                 return 0;
3361         }
3362
3363         if (trans->aborted)
3364                 return 0;
3365 again:
3366         inode = lookup_free_space_inode(root, block_group, path);
3367         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3368                 ret = PTR_ERR(inode);
3369                 btrfs_release_path(path);
3370                 goto out;
3371         }
3372
3373         if (IS_ERR(inode)) {
3374                 BUG_ON(retries);
3375                 retries++;
3376
3377                 if (block_group->ro)
3378                         goto out_free;
3379
3380                 ret = create_free_space_inode(root, trans, block_group, path);
3381                 if (ret)
3382                         goto out_free;
3383                 goto again;
3384         }
3385
3386         /* We've already setup this transaction, go ahead and exit */
3387         if (block_group->cache_generation == trans->transid &&
3388             i_size_read(inode)) {
3389                 dcs = BTRFS_DC_SETUP;
3390                 goto out_put;
3391         }
3392
3393         /*
3394          * We want to set the generation to 0, that way if anything goes wrong
3395          * from here on out we know not to trust this cache when we load up next
3396          * time.
3397          */
3398         BTRFS_I(inode)->generation = 0;
3399         ret = btrfs_update_inode(trans, root, inode);
3400         if (ret) {
3401                 /*
3402                  * So theoretically we could recover from this, simply set the
3403                  * super cache generation to 0 so we know to invalidate the
3404                  * cache, but then we'd have to keep track of the block groups
3405                  * that fail this way so we know we _have_ to reset this cache
3406                  * before the next commit or risk reading stale cache.  So to
3407                  * limit our exposure to horrible edge cases lets just abort the
3408                  * transaction, this only happens in really bad situations
3409                  * anyway.
3410                  */
3411                 btrfs_abort_transaction(trans, ret);
3412                 goto out_put;
3413         }
3414         WARN_ON(ret);
3415
3416         if (i_size_read(inode) > 0) {
3417                 ret = btrfs_check_trunc_cache_free_space(root,
3418                                         &root->fs_info->global_block_rsv);
3419                 if (ret)
3420                         goto out_put;
3421
3422                 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3423                 if (ret)
3424                         goto out_put;
3425         }
3426
3427         spin_lock(&block_group->lock);
3428         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3429             !btrfs_test_opt(root->fs_info, SPACE_CACHE)) {
3430                 /*
3431                  * don't bother trying to write stuff out _if_
3432                  * a) we're not cached,
3433                  * b) we're with nospace_cache mount option.
3434                  */
3435                 dcs = BTRFS_DC_WRITTEN;
3436                 spin_unlock(&block_group->lock);
3437                 goto out_put;
3438         }
3439         spin_unlock(&block_group->lock);
3440
3441         /*
3442          * We hit an ENOSPC when setting up the cache in this transaction, just
3443          * skip doing the setup, we've already cleared the cache so we're safe.
3444          */
3445         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3446                 ret = -ENOSPC;
3447                 goto out_put;
3448         }
3449
3450         /*
3451          * Try to preallocate enough space based on how big the block group is.
3452          * Keep in mind this has to include any pinned space which could end up
3453          * taking up quite a bit since it's not folded into the other space
3454          * cache.
3455          */
3456         num_pages = div_u64(block_group->key.offset, SZ_256M);
3457         if (!num_pages)
3458                 num_pages = 1;
3459
3460         num_pages *= 16;
3461         num_pages *= PAGE_SIZE;
3462
3463         ret = btrfs_check_data_free_space(inode, 0, num_pages);
3464         if (ret)
3465                 goto out_put;
3466
3467         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3468                                               num_pages, num_pages,
3469                                               &alloc_hint);
3470         /*
3471          * Our cache requires contiguous chunks so that we don't modify a bunch
3472          * of metadata or split extents when writing the cache out, which means
3473          * we can enospc if we are heavily fragmented in addition to just normal
3474          * out of space conditions.  So if we hit this just skip setting up any
3475          * other block groups for this transaction, maybe we'll unpin enough
3476          * space the next time around.
3477          */
3478         if (!ret)
3479                 dcs = BTRFS_DC_SETUP;
3480         else if (ret == -ENOSPC)
3481                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3482
3483 out_put:
3484         iput(inode);
3485 out_free:
3486         btrfs_release_path(path);
3487 out:
3488         spin_lock(&block_group->lock);
3489         if (!ret && dcs == BTRFS_DC_SETUP)
3490                 block_group->cache_generation = trans->transid;
3491         block_group->disk_cache_state = dcs;
3492         spin_unlock(&block_group->lock);
3493
3494         return ret;
3495 }
3496
3497 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3498                             struct btrfs_root *root)
3499 {
3500         struct btrfs_block_group_cache *cache, *tmp;
3501         struct btrfs_transaction *cur_trans = trans->transaction;
3502         struct btrfs_path *path;
3503
3504         if (list_empty(&cur_trans->dirty_bgs) ||
3505             !btrfs_test_opt(root->fs_info, SPACE_CACHE))
3506                 return 0;
3507
3508         path = btrfs_alloc_path();
3509         if (!path)
3510                 return -ENOMEM;
3511
3512         /* Could add new block groups, use _safe just in case */
3513         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3514                                  dirty_list) {
3515                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3516                         cache_save_setup(cache, trans, path);
3517         }
3518
3519         btrfs_free_path(path);
3520         return 0;
3521 }
3522
3523 /*
3524  * transaction commit does final block group cache writeback during a
3525  * critical section where nothing is allowed to change the FS.  This is
3526  * required in order for the cache to actually match the block group,
3527  * but can introduce a lot of latency into the commit.
3528  *
3529  * So, btrfs_start_dirty_block_groups is here to kick off block group
3530  * cache IO.  There's a chance we'll have to redo some of it if the
3531  * block group changes again during the commit, but it greatly reduces
3532  * the commit latency by getting rid of the easy block groups while
3533  * we're still allowing others to join the commit.
3534  */
3535 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3536                                    struct btrfs_root *root)
3537 {
3538         struct btrfs_block_group_cache *cache;
3539         struct btrfs_transaction *cur_trans = trans->transaction;
3540         int ret = 0;
3541         int should_put;
3542         struct btrfs_path *path = NULL;
3543         LIST_HEAD(dirty);
3544         struct list_head *io = &cur_trans->io_bgs;
3545         int num_started = 0;
3546         int loops = 0;
3547
3548         spin_lock(&cur_trans->dirty_bgs_lock);
3549         if (list_empty(&cur_trans->dirty_bgs)) {
3550                 spin_unlock(&cur_trans->dirty_bgs_lock);
3551                 return 0;
3552         }
3553         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3554         spin_unlock(&cur_trans->dirty_bgs_lock);
3555
3556 again:
3557         /*
3558          * make sure all the block groups on our dirty list actually
3559          * exist
3560          */
3561         btrfs_create_pending_block_groups(trans, root);
3562
3563         if (!path) {
3564                 path = btrfs_alloc_path();
3565                 if (!path)
3566                         return -ENOMEM;
3567         }
3568
3569         /*
3570          * cache_write_mutex is here only to save us from balance or automatic
3571          * removal of empty block groups deleting this block group while we are
3572          * writing out the cache
3573          */
3574         mutex_lock(&trans->transaction->cache_write_mutex);
3575         while (!list_empty(&dirty)) {
3576                 cache = list_first_entry(&dirty,
3577                                          struct btrfs_block_group_cache,
3578                                          dirty_list);
3579                 /*
3580                  * this can happen if something re-dirties a block
3581                  * group that is already under IO.  Just wait for it to
3582                  * finish and then do it all again
3583                  */
3584                 if (!list_empty(&cache->io_list)) {
3585                         list_del_init(&cache->io_list);
3586                         btrfs_wait_cache_io(root, trans, cache,
3587                                             &cache->io_ctl, path,
3588                                             cache->key.objectid);
3589                         btrfs_put_block_group(cache);
3590                 }
3591
3592
3593                 /*
3594                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3595                  * if it should update the cache_state.  Don't delete
3596                  * until after we wait.
3597                  *
3598                  * Since we're not running in the commit critical section
3599                  * we need the dirty_bgs_lock to protect from update_block_group
3600                  */
3601                 spin_lock(&cur_trans->dirty_bgs_lock);
3602                 list_del_init(&cache->dirty_list);
3603                 spin_unlock(&cur_trans->dirty_bgs_lock);
3604
3605                 should_put = 1;
3606
3607                 cache_save_setup(cache, trans, path);
3608
3609                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3610                         cache->io_ctl.inode = NULL;
3611                         ret = btrfs_write_out_cache(root, trans, cache, path);
3612                         if (ret == 0 && cache->io_ctl.inode) {
3613                                 num_started++;
3614                                 should_put = 0;
3615
3616                                 /*
3617                                  * the cache_write_mutex is protecting
3618                                  * the io_list
3619                                  */
3620                                 list_add_tail(&cache->io_list, io);
3621                         } else {
3622                                 /*
3623                                  * if we failed to write the cache, the
3624                                  * generation will be bad and life goes on
3625                                  */
3626                                 ret = 0;
3627                         }
3628                 }
3629                 if (!ret) {
3630                         ret = write_one_cache_group(trans, root, path, cache);
3631                         /*
3632                          * Our block group might still be attached to the list
3633                          * of new block groups in the transaction handle of some
3634                          * other task (struct btrfs_trans_handle->new_bgs). This
3635                          * means its block group item isn't yet in the extent
3636                          * tree. If this happens ignore the error, as we will
3637                          * try again later in the critical section of the
3638                          * transaction commit.
3639                          */
3640                         if (ret == -ENOENT) {
3641                                 ret = 0;
3642                                 spin_lock(&cur_trans->dirty_bgs_lock);
3643                                 if (list_empty(&cache->dirty_list)) {
3644                                         list_add_tail(&cache->dirty_list,
3645                                                       &cur_trans->dirty_bgs);
3646                                         btrfs_get_block_group(cache);
3647                                 }
3648                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3649                         } else if (ret) {
3650                                 btrfs_abort_transaction(trans, ret);
3651                         }
3652                 }
3653
3654                 /* if its not on the io list, we need to put the block group */
3655                 if (should_put)
3656                         btrfs_put_block_group(cache);
3657
3658                 if (ret)
3659                         break;
3660
3661                 /*
3662                  * Avoid blocking other tasks for too long. It might even save
3663                  * us from writing caches for block groups that are going to be
3664                  * removed.
3665                  */
3666                 mutex_unlock(&trans->transaction->cache_write_mutex);
3667                 mutex_lock(&trans->transaction->cache_write_mutex);
3668         }
3669         mutex_unlock(&trans->transaction->cache_write_mutex);
3670
3671         /*
3672          * go through delayed refs for all the stuff we've just kicked off
3673          * and then loop back (just once)
3674          */
3675         ret = btrfs_run_delayed_refs(trans, root, 0);
3676         if (!ret && loops == 0) {
3677                 loops++;
3678                 spin_lock(&cur_trans->dirty_bgs_lock);
3679                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3680                 /*
3681                  * dirty_bgs_lock protects us from concurrent block group
3682                  * deletes too (not just cache_write_mutex).
3683                  */
3684                 if (!list_empty(&dirty)) {
3685                         spin_unlock(&cur_trans->dirty_bgs_lock);
3686                         goto again;
3687                 }
3688                 spin_unlock(&cur_trans->dirty_bgs_lock);
3689         } else if (ret < 0) {
3690                 btrfs_cleanup_dirty_bgs(cur_trans, root);
3691         }
3692
3693         btrfs_free_path(path);
3694         return ret;
3695 }
3696
3697 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3698                                    struct btrfs_root *root)
3699 {
3700         struct btrfs_block_group_cache *cache;
3701         struct btrfs_transaction *cur_trans = trans->transaction;
3702         int ret = 0;
3703         int should_put;
3704         struct btrfs_path *path;
3705         struct list_head *io = &cur_trans->io_bgs;
3706         int num_started = 0;
3707
3708         path = btrfs_alloc_path();
3709         if (!path)
3710                 return -ENOMEM;
3711
3712         /*
3713          * Even though we are in the critical section of the transaction commit,
3714          * we can still have concurrent tasks adding elements to this
3715          * transaction's list of dirty block groups. These tasks correspond to
3716          * endio free space workers started when writeback finishes for a
3717          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3718          * allocate new block groups as a result of COWing nodes of the root
3719          * tree when updating the free space inode. The writeback for the space
3720          * caches is triggered by an earlier call to
3721          * btrfs_start_dirty_block_groups() and iterations of the following
3722          * loop.
3723          * Also we want to do the cache_save_setup first and then run the
3724          * delayed refs to make sure we have the best chance at doing this all
3725          * in one shot.
3726          */
3727         spin_lock(&cur_trans->dirty_bgs_lock);
3728         while (!list_empty(&cur_trans->dirty_bgs)) {
3729                 cache = list_first_entry(&cur_trans->dirty_bgs,
3730                                          struct btrfs_block_group_cache,
3731                                          dirty_list);
3732
3733                 /*
3734                  * this can happen if cache_save_setup re-dirties a block
3735                  * group that is already under IO.  Just wait for it to
3736                  * finish and then do it all again
3737                  */
3738                 if (!list_empty(&cache->io_list)) {
3739                         spin_unlock(&cur_trans->dirty_bgs_lock);
3740                         list_del_init(&cache->io_list);
3741                         btrfs_wait_cache_io(root, trans, cache,
3742                                             &cache->io_ctl, path,
3743                                             cache->key.objectid);
3744                         btrfs_put_block_group(cache);
3745                         spin_lock(&cur_trans->dirty_bgs_lock);
3746                 }
3747
3748                 /*
3749                  * don't remove from the dirty list until after we've waited
3750                  * on any pending IO
3751                  */
3752                 list_del_init(&cache->dirty_list);
3753                 spin_unlock(&cur_trans->dirty_bgs_lock);
3754                 should_put = 1;
3755
3756                 cache_save_setup(cache, trans, path);
3757
3758                 if (!ret)
3759                         ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3760
3761                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3762                         cache->io_ctl.inode = NULL;
3763                         ret = btrfs_write_out_cache(root, trans, cache, path);
3764                         if (ret == 0 && cache->io_ctl.inode) {
3765                                 num_started++;
3766                                 should_put = 0;
3767                                 list_add_tail(&cache->io_list, io);
3768                         } else {
3769                                 /*
3770                                  * if we failed to write the cache, the
3771                                  * generation will be bad and life goes on
3772                                  */
3773                                 ret = 0;
3774                         }
3775                 }
3776                 if (!ret) {
3777                         ret = write_one_cache_group(trans, root, path, cache);
3778                         /*
3779                          * One of the free space endio workers might have
3780                          * created a new block group while updating a free space
3781                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3782                          * and hasn't released its transaction handle yet, in
3783                          * which case the new block group is still attached to
3784                          * its transaction handle and its creation has not
3785                          * finished yet (no block group item in the extent tree
3786                          * yet, etc). If this is the case, wait for all free
3787                          * space endio workers to finish and retry. This is a
3788                          * a very rare case so no need for a more efficient and
3789                          * complex approach.
3790                          */
3791                         if (ret == -ENOENT) {
3792                                 wait_event(cur_trans->writer_wait,
3793                                    atomic_read(&cur_trans->num_writers) == 1);
3794                                 ret = write_one_cache_group(trans, root, path,
3795                                                             cache);
3796                         }
3797                         if (ret)
3798                                 btrfs_abort_transaction(trans, ret);
3799                 }
3800
3801                 /* if its not on the io list, we need to put the block group */
3802                 if (should_put)
3803                         btrfs_put_block_group(cache);
3804                 spin_lock(&cur_trans->dirty_bgs_lock);
3805         }
3806         spin_unlock(&cur_trans->dirty_bgs_lock);
3807
3808         while (!list_empty(io)) {
3809                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3810                                          io_list);
3811                 list_del_init(&cache->io_list);
3812                 btrfs_wait_cache_io(root, trans, cache,
3813                                     &cache->io_ctl, path, cache->key.objectid);
3814                 btrfs_put_block_group(cache);
3815         }
3816
3817         btrfs_free_path(path);
3818         return ret;
3819 }
3820
3821 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3822 {
3823         struct btrfs_block_group_cache *block_group;
3824         int readonly = 0;
3825
3826         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3827         if (!block_group || block_group->ro)
3828                 readonly = 1;
3829         if (block_group)
3830                 btrfs_put_block_group(block_group);
3831         return readonly;
3832 }
3833
3834 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3835 {
3836         struct btrfs_block_group_cache *bg;
3837         bool ret = true;
3838
3839         bg = btrfs_lookup_block_group(fs_info, bytenr);
3840         if (!bg)
3841                 return false;
3842
3843         spin_lock(&bg->lock);
3844         if (bg->ro)
3845                 ret = false;
3846         else
3847                 atomic_inc(&bg->nocow_writers);
3848         spin_unlock(&bg->lock);
3849
3850         /* no put on block group, done by btrfs_dec_nocow_writers */
3851         if (!ret)
3852                 btrfs_put_block_group(bg);
3853
3854         return ret;
3855
3856 }
3857
3858 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3859 {
3860         struct btrfs_block_group_cache *bg;
3861
3862         bg = btrfs_lookup_block_group(fs_info, bytenr);
3863         ASSERT(bg);
3864         if (atomic_dec_and_test(&bg->nocow_writers))
3865                 wake_up_atomic_t(&bg->nocow_writers);
3866         /*
3867          * Once for our lookup and once for the lookup done by a previous call
3868          * to btrfs_inc_nocow_writers()
3869          */
3870         btrfs_put_block_group(bg);
3871         btrfs_put_block_group(bg);
3872 }
3873
3874 static int btrfs_wait_nocow_writers_atomic_t(atomic_t *a)
3875 {
3876         schedule();
3877         return 0;
3878 }
3879
3880 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3881 {
3882         wait_on_atomic_t(&bg->nocow_writers,
3883                          btrfs_wait_nocow_writers_atomic_t,
3884                          TASK_UNINTERRUPTIBLE);
3885 }
3886
3887 static const char *alloc_name(u64 flags)
3888 {
3889         switch (flags) {
3890         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3891                 return "mixed";
3892         case BTRFS_BLOCK_GROUP_METADATA:
3893                 return "metadata";
3894         case BTRFS_BLOCK_GROUP_DATA:
3895                 return "data";
3896         case BTRFS_BLOCK_GROUP_SYSTEM:
3897                 return "system";
3898         default:
3899                 WARN_ON(1);
3900                 return "invalid-combination";
3901         };
3902 }
3903
3904 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3905                              u64 total_bytes, u64 bytes_used,
3906                              u64 bytes_readonly,
3907                              struct btrfs_space_info **space_info)
3908 {
3909         struct btrfs_space_info *found;
3910         int i;
3911         int factor;
3912         int ret;
3913
3914         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3915                      BTRFS_BLOCK_GROUP_RAID10))
3916                 factor = 2;
3917         else
3918                 factor = 1;
3919
3920         found = __find_space_info(info, flags);
3921         if (found) {
3922                 spin_lock(&found->lock);
3923                 found->total_bytes += total_bytes;
3924                 found->disk_total += total_bytes * factor;
3925                 found->bytes_used += bytes_used;
3926                 found->disk_used += bytes_used * factor;
3927                 found->bytes_readonly += bytes_readonly;
3928                 if (total_bytes > 0)
3929                         found->full = 0;
3930                 space_info_add_new_bytes(info, found, total_bytes -
3931                                          bytes_used - bytes_readonly);
3932                 spin_unlock(&found->lock);
3933                 *space_info = found;
3934                 return 0;
3935         }
3936         found = kzalloc(sizeof(*found), GFP_NOFS);
3937         if (!found)
3938                 return -ENOMEM;
3939
3940         ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3941         if (ret) {
3942                 kfree(found);
3943                 return ret;
3944         }
3945
3946         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3947                 INIT_LIST_HEAD(&found->block_groups[i]);
3948         init_rwsem(&found->groups_sem);
3949         spin_lock_init(&found->lock);
3950         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3951         found->total_bytes = total_bytes;
3952         found->disk_total = total_bytes * factor;
3953         found->bytes_used = bytes_used;
3954         found->disk_used = bytes_used * factor;
3955         found->bytes_pinned = 0;
3956         found->bytes_reserved = 0;
3957         found->bytes_readonly = bytes_readonly;
3958         found->bytes_may_use = 0;
3959         found->full = 0;
3960         found->max_extent_size = 0;
3961         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3962         found->chunk_alloc = 0;
3963         found->flush = 0;
3964         init_waitqueue_head(&found->wait);
3965         INIT_LIST_HEAD(&found->ro_bgs);
3966         INIT_LIST_HEAD(&found->tickets);
3967         INIT_LIST_HEAD(&found->priority_tickets);
3968
3969         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3970                                     info->space_info_kobj, "%s",
3971                                     alloc_name(found->flags));
3972         if (ret) {
3973                 kfree(found);
3974                 return ret;
3975         }
3976
3977         *space_info = found;
3978         list_add_rcu(&found->list, &info->space_info);
3979         if (flags & BTRFS_BLOCK_GROUP_DATA)
3980                 info->data_sinfo = found;
3981
3982         return ret;
3983 }
3984
3985 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3986 {
3987         u64 extra_flags = chunk_to_extended(flags) &
3988                                 BTRFS_EXTENDED_PROFILE_MASK;
3989
3990         write_seqlock(&fs_info->profiles_lock);
3991         if (flags & BTRFS_BLOCK_GROUP_DATA)
3992                 fs_info->avail_data_alloc_bits |= extra_flags;
3993         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3994                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3995         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3996                 fs_info->avail_system_alloc_bits |= extra_flags;
3997         write_sequnlock(&fs_info->profiles_lock);
3998 }
3999
4000 /*
4001  * returns target flags in extended format or 0 if restripe for this
4002  * chunk_type is not in progress
4003  *
4004  * should be called with either volume_mutex or balance_lock held
4005  */
4006 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4007 {
4008         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4009         u64 target = 0;
4010
4011         if (!bctl)
4012                 return 0;
4013
4014         if (flags & BTRFS_BLOCK_GROUP_DATA &&
4015             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4016                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4017         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4018                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4019                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4020         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4021                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4022                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4023         }
4024
4025         return target;
4026 }
4027
4028 /*
4029  * @flags: available profiles in extended format (see ctree.h)
4030  *
4031  * Returns reduced profile in chunk format.  If profile changing is in
4032  * progress (either running or paused) picks the target profile (if it's
4033  * already available), otherwise falls back to plain reducing.
4034  */
4035 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
4036 {
4037         u64 num_devices = root->fs_info->fs_devices->rw_devices;
4038         u64 target;
4039         u64 raid_type;
4040         u64 allowed = 0;
4041
4042         /*
4043          * see if restripe for this chunk_type is in progress, if so
4044          * try to reduce to the target profile
4045          */
4046         spin_lock(&root->fs_info->balance_lock);
4047         target = get_restripe_target(root->fs_info, flags);
4048         if (target) {
4049                 /* pick target profile only if it's already available */
4050                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4051                         spin_unlock(&root->fs_info->balance_lock);
4052                         return extended_to_chunk(target);
4053                 }
4054         }
4055         spin_unlock(&root->fs_info->balance_lock);
4056
4057         /* First, mask out the RAID levels which aren't possible */
4058         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4059                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4060                         allowed |= btrfs_raid_group[raid_type];
4061         }
4062         allowed &= flags;
4063
4064         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4065                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4066         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4067                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4068         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4069                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4070         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4071                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4072         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4073                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4074
4075         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4076
4077         return extended_to_chunk(flags | allowed);
4078 }
4079
4080 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
4081 {
4082         unsigned seq;
4083         u64 flags;
4084
4085         do {
4086                 flags = orig_flags;
4087                 seq = read_seqbegin(&root->fs_info->profiles_lock);
4088
4089                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4090                         flags |= root->fs_info->avail_data_alloc_bits;
4091                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4092                         flags |= root->fs_info->avail_system_alloc_bits;
4093                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4094                         flags |= root->fs_info->avail_metadata_alloc_bits;
4095         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
4096
4097         return btrfs_reduce_alloc_profile(root, flags);
4098 }
4099
4100 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
4101 {
4102         u64 flags;
4103         u64 ret;
4104
4105         if (data)
4106                 flags = BTRFS_BLOCK_GROUP_DATA;
4107         else if (root == root->fs_info->chunk_root)
4108                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4109         else
4110                 flags = BTRFS_BLOCK_GROUP_METADATA;
4111
4112         ret = get_alloc_profile(root, flags);
4113         return ret;
4114 }
4115
4116 int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
4117 {
4118         struct btrfs_space_info *data_sinfo;
4119         struct btrfs_root *root = BTRFS_I(inode)->root;
4120         struct btrfs_fs_info *fs_info = root->fs_info;
4121         u64 used;
4122         int ret = 0;
4123         int need_commit = 2;
4124         int have_pinned_space;
4125
4126         /* make sure bytes are sectorsize aligned */
4127         bytes = ALIGN(bytes, root->sectorsize);
4128
4129         if (btrfs_is_free_space_inode(inode)) {
4130                 need_commit = 0;
4131                 ASSERT(current->journal_info);
4132         }
4133
4134         data_sinfo = fs_info->data_sinfo;
4135         if (!data_sinfo)
4136                 goto alloc;
4137
4138 again:
4139         /* make sure we have enough space to handle the data first */
4140         spin_lock(&data_sinfo->lock);
4141         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
4142                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
4143                 data_sinfo->bytes_may_use;
4144
4145         if (used + bytes > data_sinfo->total_bytes) {
4146                 struct btrfs_trans_handle *trans;
4147
4148                 /*
4149                  * if we don't have enough free bytes in this space then we need
4150                  * to alloc a new chunk.
4151                  */
4152                 if (!data_sinfo->full) {
4153                         u64 alloc_target;
4154
4155                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4156                         spin_unlock(&data_sinfo->lock);
4157 alloc:
4158                         alloc_target = btrfs_get_alloc_profile(root, 1);
4159                         /*
4160                          * It is ugly that we don't call nolock join
4161                          * transaction for the free space inode case here.
4162                          * But it is safe because we only do the data space
4163                          * reservation for the free space cache in the
4164                          * transaction context, the common join transaction
4165                          * just increase the counter of the current transaction
4166                          * handler, doesn't try to acquire the trans_lock of
4167                          * the fs.
4168                          */
4169                         trans = btrfs_join_transaction(root);
4170                         if (IS_ERR(trans))
4171                                 return PTR_ERR(trans);
4172
4173                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4174                                              alloc_target,
4175                                              CHUNK_ALLOC_NO_FORCE);
4176                         btrfs_end_transaction(trans, root);
4177                         if (ret < 0) {
4178                                 if (ret != -ENOSPC)
4179                                         return ret;
4180                                 else {
4181                                         have_pinned_space = 1;
4182                                         goto commit_trans;
4183                                 }
4184                         }
4185
4186                         if (!data_sinfo)
4187                                 data_sinfo = fs_info->data_sinfo;
4188
4189                         goto again;
4190                 }
4191
4192                 /*
4193                  * If we don't have enough pinned space to deal with this
4194                  * allocation, and no removed chunk in current transaction,
4195                  * don't bother committing the transaction.
4196                  */
4197                 have_pinned_space = percpu_counter_compare(
4198                         &data_sinfo->total_bytes_pinned,
4199                         used + bytes - data_sinfo->total_bytes);
4200                 spin_unlock(&data_sinfo->lock);
4201
4202                 /* commit the current transaction and try again */
4203 commit_trans:
4204                 if (need_commit &&
4205                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
4206                         need_commit--;
4207
4208                         if (need_commit > 0) {
4209                                 btrfs_start_delalloc_roots(fs_info, 0, -1);
4210                                 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
4211                         }
4212
4213                         trans = btrfs_join_transaction(root);
4214                         if (IS_ERR(trans))
4215                                 return PTR_ERR(trans);
4216                         if (have_pinned_space >= 0 ||
4217                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4218                                      &trans->transaction->flags) ||
4219                             need_commit > 0) {
4220                                 ret = btrfs_commit_transaction(trans, root);
4221                                 if (ret)
4222                                         return ret;
4223                                 /*
4224                                  * The cleaner kthread might still be doing iput
4225                                  * operations. Wait for it to finish so that
4226                                  * more space is released.
4227                                  */
4228                                 mutex_lock(&root->fs_info->cleaner_delayed_iput_mutex);
4229                                 mutex_unlock(&root->fs_info->cleaner_delayed_iput_mutex);
4230                                 goto again;
4231                         } else {
4232                                 btrfs_end_transaction(trans, root);
4233                         }
4234                 }
4235
4236                 trace_btrfs_space_reservation(root->fs_info,
4237                                               "space_info:enospc",
4238                                               data_sinfo->flags, bytes, 1);
4239                 return -ENOSPC;
4240         }
4241         data_sinfo->bytes_may_use += bytes;
4242         trace_btrfs_space_reservation(root->fs_info, "space_info",
4243                                       data_sinfo->flags, bytes, 1);
4244         spin_unlock(&data_sinfo->lock);
4245
4246         return ret;
4247 }
4248
4249 /*
4250  * New check_data_free_space() with ability for precious data reservation
4251  * Will replace old btrfs_check_data_free_space(), but for patch split,
4252  * add a new function first and then replace it.
4253  */
4254 int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4255 {
4256         struct btrfs_root *root = BTRFS_I(inode)->root;
4257         int ret;
4258
4259         /* align the range */
4260         len = round_up(start + len, root->sectorsize) -
4261               round_down(start, root->sectorsize);
4262         start = round_down(start, root->sectorsize);
4263
4264         ret = btrfs_alloc_data_chunk_ondemand(inode, len);
4265         if (ret < 0)
4266                 return ret;
4267
4268         /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4269         ret = btrfs_qgroup_reserve_data(inode, start, len);
4270         if (ret)
4271                 btrfs_free_reserved_data_space_noquota(inode, start, len);
4272         return ret;
4273 }
4274
4275 /*
4276  * Called if we need to clear a data reservation for this inode
4277  * Normally in a error case.
4278  *
4279  * This one will *NOT* use accurate qgroup reserved space API, just for case
4280  * which we can't sleep and is sure it won't affect qgroup reserved space.
4281  * Like clear_bit_hook().
4282  */
4283 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4284                                             u64 len)
4285 {
4286         struct btrfs_root *root = BTRFS_I(inode)->root;
4287         struct btrfs_space_info *data_sinfo;
4288
4289         /* Make sure the range is aligned to sectorsize */
4290         len = round_up(start + len, root->sectorsize) -
4291               round_down(start, root->sectorsize);
4292         start = round_down(start, root->sectorsize);
4293
4294         data_sinfo = root->fs_info->data_sinfo;
4295         spin_lock(&data_sinfo->lock);
4296         if (WARN_ON(data_sinfo->bytes_may_use < len))
4297                 data_sinfo->bytes_may_use = 0;
4298         else
4299                 data_sinfo->bytes_may_use -= len;
4300         trace_btrfs_space_reservation(root->fs_info, "space_info",
4301                                       data_sinfo->flags, len, 0);
4302         spin_unlock(&data_sinfo->lock);
4303 }
4304
4305 /*
4306  * Called if we need to clear a data reservation for this inode
4307  * Normally in a error case.
4308  *
4309  * This one will handle the per-inode data rsv map for accurate reserved
4310  * space framework.
4311  */
4312 void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4313 {
4314         btrfs_free_reserved_data_space_noquota(inode, start, len);
4315         btrfs_qgroup_free_data(inode, start, len);
4316 }
4317
4318 static void force_metadata_allocation(struct btrfs_fs_info *info)
4319 {
4320         struct list_head *head = &info->space_info;
4321         struct btrfs_space_info *found;
4322
4323         rcu_read_lock();
4324         list_for_each_entry_rcu(found, head, list) {
4325                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4326                         found->force_alloc = CHUNK_ALLOC_FORCE;
4327         }
4328         rcu_read_unlock();
4329 }
4330
4331 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4332 {
4333         return (global->size << 1);
4334 }
4335
4336 static int should_alloc_chunk(struct btrfs_root *root,
4337                               struct btrfs_space_info *sinfo, int force)
4338 {
4339         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4340         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4341         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4342         u64 thresh;
4343
4344         if (force == CHUNK_ALLOC_FORCE)
4345                 return 1;
4346
4347         /*
4348          * We need to take into account the global rsv because for all intents
4349          * and purposes it's used space.  Don't worry about locking the
4350          * global_rsv, it doesn't change except when the transaction commits.
4351          */
4352         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4353                 num_allocated += calc_global_rsv_need_space(global_rsv);
4354
4355         /*
4356          * in limited mode, we want to have some free space up to
4357          * about 1% of the FS size.
4358          */
4359         if (force == CHUNK_ALLOC_LIMITED) {
4360                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4361                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4362
4363                 if (num_bytes - num_allocated < thresh)
4364                         return 1;
4365         }
4366
4367         if (num_allocated + SZ_2M < div_factor(num_bytes, 8))
4368                 return 0;
4369         return 1;
4370 }
4371
4372 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4373 {
4374         u64 num_dev;
4375
4376         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4377                     BTRFS_BLOCK_GROUP_RAID0 |
4378                     BTRFS_BLOCK_GROUP_RAID5 |
4379                     BTRFS_BLOCK_GROUP_RAID6))
4380                 num_dev = root->fs_info->fs_devices->rw_devices;
4381         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4382                 num_dev = 2;
4383         else
4384                 num_dev = 1;    /* DUP or single */
4385
4386         return num_dev;
4387 }
4388
4389 /*
4390  * If @is_allocation is true, reserve space in the system space info necessary
4391  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4392  * removing a chunk.
4393  */
4394 void check_system_chunk(struct btrfs_trans_handle *trans,
4395                         struct btrfs_root *root,
4396                         u64 type)
4397 {
4398         struct btrfs_space_info *info;
4399         u64 left;
4400         u64 thresh;
4401         int ret = 0;
4402         u64 num_devs;
4403
4404         /*
4405          * Needed because we can end up allocating a system chunk and for an
4406          * atomic and race free space reservation in the chunk block reserve.
4407          */
4408         ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4409
4410         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4411         spin_lock(&info->lock);
4412         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4413                 info->bytes_reserved - info->bytes_readonly -
4414                 info->bytes_may_use;
4415         spin_unlock(&info->lock);
4416
4417         num_devs = get_profile_num_devs(root, type);
4418
4419         /* num_devs device items to update and 1 chunk item to add or remove */
4420         thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4421                 btrfs_calc_trans_metadata_size(root, 1);
4422
4423         if (left < thresh && btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
4424                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4425                         left, thresh, type);
4426                 dump_space_info(info, 0, 0);
4427         }
4428
4429         if (left < thresh) {
4430                 u64 flags;
4431
4432                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4433                 /*
4434                  * Ignore failure to create system chunk. We might end up not
4435                  * needing it, as we might not need to COW all nodes/leafs from
4436                  * the paths we visit in the chunk tree (they were already COWed
4437                  * or created in the current transaction for example).
4438                  */
4439                 ret = btrfs_alloc_chunk(trans, root, flags);
4440         }
4441
4442         if (!ret) {
4443                 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4444                                           &root->fs_info->chunk_block_rsv,
4445                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4446                 if (!ret)
4447                         trans->chunk_bytes_reserved += thresh;
4448         }
4449 }
4450
4451 /*
4452  * If force is CHUNK_ALLOC_FORCE:
4453  *    - return 1 if it successfully allocates a chunk,
4454  *    - return errors including -ENOSPC otherwise.
4455  * If force is NOT CHUNK_ALLOC_FORCE:
4456  *    - return 0 if it doesn't need to allocate a new chunk,
4457  *    - return 1 if it successfully allocates a chunk,
4458  *    - return errors including -ENOSPC otherwise.
4459  */
4460 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4461                           struct btrfs_root *extent_root, u64 flags, int force)
4462 {
4463         struct btrfs_space_info *space_info;
4464         struct btrfs_fs_info *fs_info = extent_root->fs_info;
4465         int wait_for_alloc = 0;
4466         int ret = 0;
4467
4468         /* Don't re-enter if we're already allocating a chunk */
4469         if (trans->allocating_chunk)
4470                 return -ENOSPC;
4471
4472         space_info = __find_space_info(extent_root->fs_info, flags);
4473         if (!space_info) {
4474                 ret = update_space_info(extent_root->fs_info, flags,
4475                                         0, 0, 0, &space_info);
4476                 BUG_ON(ret); /* -ENOMEM */
4477         }
4478         BUG_ON(!space_info); /* Logic error */
4479
4480 again:
4481         spin_lock(&space_info->lock);
4482         if (force < space_info->force_alloc)
4483                 force = space_info->force_alloc;
4484         if (space_info->full) {
4485                 if (should_alloc_chunk(extent_root, space_info, force))
4486                         ret = -ENOSPC;
4487                 else
4488                         ret = 0;
4489                 spin_unlock(&space_info->lock);
4490                 return ret;
4491         }
4492
4493         if (!should_alloc_chunk(extent_root, space_info, force)) {
4494                 spin_unlock(&space_info->lock);
4495                 return 0;
4496         } else if (space_info->chunk_alloc) {
4497                 wait_for_alloc = 1;
4498         } else {
4499                 space_info->chunk_alloc = 1;
4500         }
4501
4502         spin_unlock(&space_info->lock);
4503
4504         mutex_lock(&fs_info->chunk_mutex);
4505
4506         /*
4507          * The chunk_mutex is held throughout the entirety of a chunk
4508          * allocation, so once we've acquired the chunk_mutex we know that the
4509          * other guy is done and we need to recheck and see if we should
4510          * allocate.
4511          */
4512         if (wait_for_alloc) {
4513                 mutex_unlock(&fs_info->chunk_mutex);
4514                 wait_for_alloc = 0;
4515                 goto again;
4516         }
4517
4518         trans->allocating_chunk = true;
4519
4520         /*
4521          * If we have mixed data/metadata chunks we want to make sure we keep
4522          * allocating mixed chunks instead of individual chunks.
4523          */
4524         if (btrfs_mixed_space_info(space_info))
4525                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4526
4527         /*
4528          * if we're doing a data chunk, go ahead and make sure that
4529          * we keep a reasonable number of metadata chunks allocated in the
4530          * FS as well.
4531          */
4532         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4533                 fs_info->data_chunk_allocations++;
4534                 if (!(fs_info->data_chunk_allocations %
4535                       fs_info->metadata_ratio))
4536                         force_metadata_allocation(fs_info);
4537         }
4538
4539         /*
4540          * Check if we have enough space in SYSTEM chunk because we may need
4541          * to update devices.
4542          */
4543         check_system_chunk(trans, extent_root, flags);
4544
4545         ret = btrfs_alloc_chunk(trans, extent_root, flags);
4546         trans->allocating_chunk = false;
4547
4548         spin_lock(&space_info->lock);
4549         if (ret < 0 && ret != -ENOSPC)
4550                 goto out;
4551         if (ret)
4552                 space_info->full = 1;
4553         else
4554                 ret = 1;
4555
4556         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4557 out:
4558         space_info->chunk_alloc = 0;
4559         spin_unlock(&space_info->lock);
4560         mutex_unlock(&fs_info->chunk_mutex);
4561         /*
4562          * When we allocate a new chunk we reserve space in the chunk block
4563          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4564          * add new nodes/leafs to it if we end up needing to do it when
4565          * inserting the chunk item and updating device items as part of the
4566          * second phase of chunk allocation, performed by
4567          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4568          * large number of new block groups to create in our transaction
4569          * handle's new_bgs list to avoid exhausting the chunk block reserve
4570          * in extreme cases - like having a single transaction create many new
4571          * block groups when starting to write out the free space caches of all
4572          * the block groups that were made dirty during the lifetime of the
4573          * transaction.
4574          */
4575         if (trans->can_flush_pending_bgs &&
4576             trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4577                 btrfs_create_pending_block_groups(trans, extent_root);
4578                 btrfs_trans_release_chunk_metadata(trans);
4579         }
4580         return ret;
4581 }
4582
4583 static int can_overcommit(struct btrfs_root *root,
4584                           struct btrfs_space_info *space_info, u64 bytes,
4585                           enum btrfs_reserve_flush_enum flush)
4586 {
4587         struct btrfs_block_rsv *global_rsv;
4588         u64 profile;
4589         u64 space_size;
4590         u64 avail;
4591         u64 used;
4592
4593         /* Don't overcommit when in mixed mode. */
4594         if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4595                 return 0;
4596
4597         BUG_ON(root->fs_info == NULL);
4598         global_rsv = &root->fs_info->global_block_rsv;
4599         profile = btrfs_get_alloc_profile(root, 0);
4600         used = space_info->bytes_used + space_info->bytes_reserved +
4601                 space_info->bytes_pinned + space_info->bytes_readonly;
4602
4603         /*
4604          * We only want to allow over committing if we have lots of actual space
4605          * free, but if we don't have enough space to handle the global reserve
4606          * space then we could end up having a real enospc problem when trying
4607          * to allocate a chunk or some other such important allocation.
4608          */
4609         spin_lock(&global_rsv->lock);
4610         space_size = calc_global_rsv_need_space(global_rsv);
4611         spin_unlock(&global_rsv->lock);
4612         if (used + space_size >= space_info->total_bytes)
4613                 return 0;
4614
4615         used += space_info->bytes_may_use;
4616
4617         spin_lock(&root->fs_info->free_chunk_lock);
4618         avail = root->fs_info->free_chunk_space;
4619         spin_unlock(&root->fs_info->free_chunk_lock);
4620
4621         /*
4622          * If we have dup, raid1 or raid10 then only half of the free
4623          * space is actually useable.  For raid56, the space info used
4624          * doesn't include the parity drive, so we don't have to
4625          * change the math
4626          */
4627         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4628                        BTRFS_BLOCK_GROUP_RAID1 |
4629                        BTRFS_BLOCK_GROUP_RAID10))
4630                 avail >>= 1;
4631
4632         /*
4633          * If we aren't flushing all things, let us overcommit up to
4634          * 1/2th of the space. If we can flush, don't let us overcommit
4635          * too much, let it overcommit up to 1/8 of the space.
4636          */
4637         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4638                 avail >>= 3;
4639         else
4640                 avail >>= 1;
4641
4642         if (used + bytes < space_info->total_bytes + avail)
4643                 return 1;
4644         return 0;
4645 }
4646
4647 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4648                                          unsigned long nr_pages, int nr_items)
4649 {
4650         struct super_block *sb = root->fs_info->sb;
4651
4652         if (down_read_trylock(&sb->s_umount)) {
4653                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4654                 up_read(&sb->s_umount);
4655         } else {
4656                 /*
4657                  * We needn't worry the filesystem going from r/w to r/o though
4658                  * we don't acquire ->s_umount mutex, because the filesystem
4659                  * should guarantee the delalloc inodes list be empty after
4660                  * the filesystem is readonly(all dirty pages are written to
4661                  * the disk).
4662                  */
4663                 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4664                 if (!current->journal_info)
4665                         btrfs_wait_ordered_roots(root->fs_info, nr_items,
4666                                                  0, (u64)-1);
4667         }
4668 }
4669
4670 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4671 {
4672         u64 bytes;
4673         int nr;
4674
4675         bytes = btrfs_calc_trans_metadata_size(root, 1);
4676         nr = (int)div64_u64(to_reclaim, bytes);
4677         if (!nr)
4678                 nr = 1;
4679         return nr;
4680 }
4681
4682 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4683
4684 /*
4685  * shrink metadata reservation for delalloc
4686  */
4687 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4688                             bool wait_ordered)
4689 {
4690         struct btrfs_block_rsv *block_rsv;
4691         struct btrfs_space_info *space_info;
4692         struct btrfs_trans_handle *trans;
4693         u64 delalloc_bytes;
4694         u64 max_reclaim;
4695         long time_left;
4696         unsigned long nr_pages;
4697         int loops;
4698         int items;
4699         enum btrfs_reserve_flush_enum flush;
4700
4701         /* Calc the number of the pages we need flush for space reservation */
4702         items = calc_reclaim_items_nr(root, to_reclaim);
4703         to_reclaim = (u64)items * EXTENT_SIZE_PER_ITEM;
4704
4705         trans = (struct btrfs_trans_handle *)current->journal_info;
4706         block_rsv = &root->fs_info->delalloc_block_rsv;
4707         space_info = block_rsv->space_info;
4708
4709         delalloc_bytes = percpu_counter_sum_positive(
4710                                                 &root->fs_info->delalloc_bytes);
4711         if (delalloc_bytes == 0) {
4712                 if (trans)
4713                         return;
4714                 if (wait_ordered)
4715                         btrfs_wait_ordered_roots(root->fs_info, items,
4716                                                  0, (u64)-1);
4717                 return;
4718         }
4719
4720         loops = 0;
4721         while (delalloc_bytes && loops < 3) {
4722                 max_reclaim = min(delalloc_bytes, to_reclaim);
4723                 nr_pages = max_reclaim >> PAGE_SHIFT;
4724                 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4725                 /*
4726                  * We need to wait for the async pages to actually start before
4727                  * we do anything.
4728                  */
4729                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4730                 if (!max_reclaim)
4731                         goto skip_async;
4732
4733                 if (max_reclaim <= nr_pages)
4734                         max_reclaim = 0;
4735                 else
4736                         max_reclaim -= nr_pages;
4737
4738                 wait_event(root->fs_info->async_submit_wait,
4739                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4740                            (int)max_reclaim);
4741 skip_async:
4742                 if (!trans)
4743                         flush = BTRFS_RESERVE_FLUSH_ALL;
4744                 else
4745                         flush = BTRFS_RESERVE_NO_FLUSH;
4746                 spin_lock(&space_info->lock);
4747                 if (can_overcommit(root, space_info, orig, flush)) {
4748                         spin_unlock(&space_info->lock);
4749                         break;
4750                 }
4751                 if (list_empty(&space_info->tickets) &&
4752                     list_empty(&space_info->priority_tickets)) {
4753                         spin_unlock(&space_info->lock);
4754                         break;
4755                 }
4756                 spin_unlock(&space_info->lock);
4757
4758                 loops++;
4759                 if (wait_ordered && !trans) {
4760                         btrfs_wait_ordered_roots(root->fs_info, items,
4761                                                  0, (u64)-1);
4762                 } else {
4763                         time_left = schedule_timeout_killable(1);
4764                         if (time_left)
4765                                 break;
4766                 }
4767                 delalloc_bytes = percpu_counter_sum_positive(
4768                                                 &root->fs_info->delalloc_bytes);
4769         }
4770 }
4771
4772 /**
4773  * maybe_commit_transaction - possibly commit the transaction if its ok to
4774  * @root - the root we're allocating for
4775  * @bytes - the number of bytes we want to reserve
4776  * @force - force the commit
4777  *
4778  * This will check to make sure that committing the transaction will actually
4779  * get us somewhere and then commit the transaction if it does.  Otherwise it
4780  * will return -ENOSPC.
4781  */
4782 static int may_commit_transaction(struct btrfs_root *root,
4783                                   struct btrfs_space_info *space_info,
4784                                   u64 bytes, int force)
4785 {
4786         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4787         struct btrfs_trans_handle *trans;
4788
4789         trans = (struct btrfs_trans_handle *)current->journal_info;
4790         if (trans)
4791                 return -EAGAIN;
4792
4793         if (force)
4794                 goto commit;
4795
4796         /* See if there is enough pinned space to make this reservation */
4797         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4798                                    bytes) >= 0)
4799                 goto commit;
4800
4801         /*
4802          * See if there is some space in the delayed insertion reservation for
4803          * this reservation.
4804          */
4805         if (space_info != delayed_rsv->space_info)
4806                 return -ENOSPC;
4807
4808         spin_lock(&delayed_rsv->lock);
4809         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4810                                    bytes - delayed_rsv->size) >= 0) {
4811                 spin_unlock(&delayed_rsv->lock);
4812                 return -ENOSPC;
4813         }
4814         spin_unlock(&delayed_rsv->lock);
4815
4816 commit:
4817         trans = btrfs_join_transaction(root);
4818         if (IS_ERR(trans))
4819                 return -ENOSPC;
4820
4821         return btrfs_commit_transaction(trans, root);
4822 }
4823
4824 struct reserve_ticket {
4825         u64 bytes;
4826         int error;
4827         struct list_head list;
4828         wait_queue_head_t wait;
4829 };
4830
4831 static int flush_space(struct btrfs_root *root,
4832                        struct btrfs_space_info *space_info, u64 num_bytes,
4833                        u64 orig_bytes, int state)
4834 {
4835         struct btrfs_trans_handle *trans;
4836         int nr;
4837         int ret = 0;
4838
4839         switch (state) {
4840         case FLUSH_DELAYED_ITEMS_NR:
4841         case FLUSH_DELAYED_ITEMS:
4842                 if (state == FLUSH_DELAYED_ITEMS_NR)
4843                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4844                 else
4845                         nr = -1;
4846
4847                 trans = btrfs_join_transaction(root);
4848                 if (IS_ERR(trans)) {
4849                         ret = PTR_ERR(trans);
4850                         break;
4851                 }
4852                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4853                 btrfs_end_transaction(trans, root);
4854                 break;
4855         case FLUSH_DELALLOC:
4856         case FLUSH_DELALLOC_WAIT:
4857                 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4858                                 state == FLUSH_DELALLOC_WAIT);
4859                 break;
4860         case ALLOC_CHUNK:
4861                 trans = btrfs_join_transaction(root);
4862                 if (IS_ERR(trans)) {
4863                         ret = PTR_ERR(trans);
4864                         break;
4865                 }
4866                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4867                                      btrfs_get_alloc_profile(root, 0),
4868                                      CHUNK_ALLOC_NO_FORCE);
4869                 btrfs_end_transaction(trans, root);
4870                 if (ret > 0 || ret == -ENOSPC)
4871                         ret = 0;
4872                 break;
4873         case COMMIT_TRANS:
4874                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4875                 break;
4876         default:
4877                 ret = -ENOSPC;
4878                 break;
4879         }
4880
4881         trace_btrfs_flush_space(root->fs_info, space_info->flags, num_bytes,
4882                                 orig_bytes, state, ret);
4883         return ret;
4884 }
4885
4886 static inline u64
4887 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4888                                  struct btrfs_space_info *space_info)
4889 {
4890         struct reserve_ticket *ticket;
4891         u64 used;
4892         u64 expected;
4893         u64 to_reclaim = 0;
4894
4895         list_for_each_entry(ticket, &space_info->tickets, list)
4896                 to_reclaim += ticket->bytes;
4897         list_for_each_entry(ticket, &space_info->priority_tickets, list)
4898                 to_reclaim += ticket->bytes;
4899         if (to_reclaim)
4900                 return to_reclaim;
4901
4902         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4903         if (can_overcommit(root, space_info, to_reclaim,
4904                            BTRFS_RESERVE_FLUSH_ALL))
4905                 return 0;
4906
4907         used = space_info->bytes_used + space_info->bytes_reserved +
4908                space_info->bytes_pinned + space_info->bytes_readonly +
4909                space_info->bytes_may_use;
4910         if (can_overcommit(root, space_info, SZ_1M, BTRFS_RESERVE_FLUSH_ALL))
4911                 expected = div_factor_fine(space_info->total_bytes, 95);
4912         else
4913                 expected = div_factor_fine(space_info->total_bytes, 90);
4914
4915         if (used > expected)
4916                 to_reclaim = used - expected;
4917         else
4918                 to_reclaim = 0;
4919         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4920                                      space_info->bytes_reserved);
4921         return to_reclaim;
4922 }
4923
4924 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4925                                         struct btrfs_root *root, u64 used)
4926 {
4927         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4928
4929         /* If we're just plain full then async reclaim just slows us down. */
4930         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4931                 return 0;
4932
4933         if (!btrfs_calc_reclaim_metadata_size(root, space_info))
4934                 return 0;
4935
4936         return (used >= thresh && !btrfs_fs_closing(root->fs_info) &&
4937                 !test_bit(BTRFS_FS_STATE_REMOUNTING,
4938                           &root->fs_info->fs_state));
4939 }
4940
4941 static void wake_all_tickets(struct list_head *head)
4942 {
4943         struct reserve_ticket *ticket;
4944
4945         while (!list_empty(head)) {
4946                 ticket = list_first_entry(head, struct reserve_ticket, list);
4947                 list_del_init(&ticket->list);
4948                 ticket->error = -ENOSPC;
4949                 wake_up(&ticket->wait);
4950         }
4951 }
4952
4953 /*
4954  * This is for normal flushers, we can wait all goddamned day if we want to.  We
4955  * will loop and continuously try to flush as long as we are making progress.
4956  * We count progress as clearing off tickets each time we have to loop.
4957  */
4958 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4959 {
4960         struct btrfs_fs_info *fs_info;
4961         struct btrfs_space_info *space_info;
4962         u64 to_reclaim;
4963         int flush_state;
4964         int commit_cycles = 0;
4965         u64 last_tickets_id;
4966
4967         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4968         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4969
4970         spin_lock(&space_info->lock);
4971         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4972                                                       space_info);
4973         if (!to_reclaim) {
4974                 space_info->flush = 0;
4975                 spin_unlock(&space_info->lock);
4976                 return;
4977         }
4978         last_tickets_id = space_info->tickets_id;
4979         spin_unlock(&space_info->lock);
4980
4981         flush_state = FLUSH_DELAYED_ITEMS_NR;
4982         do {
4983                 struct reserve_ticket *ticket;
4984                 int ret;
4985
4986                 ret = flush_space(fs_info->fs_root, space_info, to_reclaim,
4987                             to_reclaim, flush_state);
4988                 spin_lock(&space_info->lock);
4989                 if (list_empty(&space_info->tickets)) {
4990                         space_info->flush = 0;
4991                         spin_unlock(&space_info->lock);
4992                         return;
4993                 }
4994                 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4995                                                               space_info);
4996                 ticket = list_first_entry(&space_info->tickets,
4997                                           struct reserve_ticket, list);
4998                 if (last_tickets_id == space_info->tickets_id) {
4999                         flush_state++;
5000                 } else {
5001                         last_tickets_id = space_info->tickets_id;
5002                         flush_state = FLUSH_DELAYED_ITEMS_NR;
5003                         if (commit_cycles)
5004                                 commit_cycles--;
5005                 }
5006
5007                 if (flush_state > COMMIT_TRANS) {
5008                         commit_cycles++;
5009                         if (commit_cycles > 2) {
5010                                 wake_all_tickets(&space_info->tickets);
5011                                 space_info->flush = 0;
5012                         } else {
5013                                 flush_state = FLUSH_DELAYED_ITEMS_NR;
5014                         }
5015                 }
5016                 spin_unlock(&space_info->lock);
5017         } while (flush_state <= COMMIT_TRANS);
5018 }
5019
5020 void btrfs_init_async_reclaim_work(struct work_struct *work)
5021 {
5022         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5023 }
5024
5025 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5026                                             struct btrfs_space_info *space_info,
5027                                             struct reserve_ticket *ticket)
5028 {
5029         u64 to_reclaim;
5030         int flush_state = FLUSH_DELAYED_ITEMS_NR;
5031
5032         spin_lock(&space_info->lock);
5033         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5034                                                       space_info);
5035         if (!to_reclaim) {
5036                 spin_unlock(&space_info->lock);
5037                 return;
5038         }
5039         spin_unlock(&space_info->lock);
5040
5041         do {
5042                 flush_space(fs_info->fs_root, space_info, to_reclaim,
5043                             to_reclaim, flush_state);
5044                 flush_state++;
5045                 spin_lock(&space_info->lock);
5046                 if (ticket->bytes == 0) {
5047                         spin_unlock(&space_info->lock);
5048                         return;
5049                 }
5050                 spin_unlock(&space_info->lock);
5051
5052                 /*
5053                  * Priority flushers can't wait on delalloc without
5054                  * deadlocking.
5055                  */
5056                 if (flush_state == FLUSH_DELALLOC ||
5057                     flush_state == FLUSH_DELALLOC_WAIT)
5058                         flush_state = ALLOC_CHUNK;
5059         } while (flush_state < COMMIT_TRANS);
5060 }
5061
5062 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5063                                struct btrfs_space_info *space_info,
5064                                struct reserve_ticket *ticket, u64 orig_bytes)
5065
5066 {
5067         DEFINE_WAIT(wait);
5068         int ret = 0;
5069
5070         spin_lock(&space_info->lock);
5071         while (ticket->bytes > 0 && ticket->error == 0) {
5072                 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5073                 if (ret) {
5074                         ret = -EINTR;
5075                         break;
5076                 }
5077                 spin_unlock(&space_info->lock);
5078
5079                 schedule();
5080
5081                 finish_wait(&ticket->wait, &wait);
5082                 spin_lock(&space_info->lock);
5083         }
5084         if (!ret)
5085                 ret = ticket->error;
5086         if (!list_empty(&ticket->list))
5087                 list_del_init(&ticket->list);
5088         if (ticket->bytes && ticket->bytes < orig_bytes) {
5089                 u64 num_bytes = orig_bytes - ticket->bytes;
5090                 space_info->bytes_may_use -= num_bytes;
5091                 trace_btrfs_space_reservation(fs_info, "space_info",
5092                                               space_info->flags, num_bytes, 0);
5093         }
5094         spin_unlock(&space_info->lock);
5095
5096         return ret;
5097 }
5098
5099 /**
5100  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5101  * @root - the root we're allocating for
5102  * @space_info - the space info we want to allocate from
5103  * @orig_bytes - the number of bytes we want
5104  * @flush - whether or not we can flush to make our reservation
5105  *
5106  * This will reserve orig_bytes number of bytes from the space info associated
5107  * with the block_rsv.  If there is not enough space it will make an attempt to
5108  * flush out space to make room.  It will do this by flushing delalloc if
5109  * possible or committing the transaction.  If flush is 0 then no attempts to
5110  * regain reservations will be made and this will fail if there is not enough
5111  * space already.
5112  */
5113 static int __reserve_metadata_bytes(struct btrfs_root *root,
5114                                     struct btrfs_space_info *space_info,
5115                                     u64 orig_bytes,
5116                                     enum btrfs_reserve_flush_enum flush)
5117 {
5118         struct reserve_ticket ticket;
5119         u64 used;
5120         int ret = 0;
5121
5122         ASSERT(orig_bytes);
5123         ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5124
5125         spin_lock(&space_info->lock);
5126         ret = -ENOSPC;
5127         used = space_info->bytes_used + space_info->bytes_reserved +
5128                 space_info->bytes_pinned + space_info->bytes_readonly +
5129                 space_info->bytes_may_use;
5130
5131         /*
5132          * If we have enough space then hooray, make our reservation and carry
5133          * on.  If not see if we can overcommit, and if we can, hooray carry on.
5134          * If not things get more complicated.
5135          */
5136         if (used + orig_bytes <= space_info->total_bytes) {
5137                 space_info->bytes_may_use += orig_bytes;
5138                 trace_btrfs_space_reservation(root->fs_info, "space_info",
5139                                               space_info->flags, orig_bytes,
5140                                               1);
5141                 ret = 0;
5142         } else if (can_overcommit(root, space_info, orig_bytes, flush)) {
5143                 space_info->bytes_may_use += orig_bytes;
5144                 trace_btrfs_space_reservation(root->fs_info, "space_info",
5145                                               space_info->flags, orig_bytes,
5146                                               1);
5147                 ret = 0;
5148         }
5149
5150         /*
5151          * If we couldn't make a reservation then setup our reservation ticket
5152          * and kick the async worker if it's not already running.
5153          *
5154          * If we are a priority flusher then we just need to add our ticket to
5155          * the list and we will do our own flushing further down.
5156          */
5157         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5158                 ticket.bytes = orig_bytes;
5159                 ticket.error = 0;
5160                 init_waitqueue_head(&ticket.wait);
5161                 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5162                         list_add_tail(&ticket.list, &space_info->tickets);
5163                         if (!space_info->flush) {
5164                                 space_info->flush = 1;
5165                                 trace_btrfs_trigger_flush(root->fs_info,
5166                                                           space_info->flags,
5167                                                           orig_bytes, flush,
5168                                                           "enospc");
5169                                 queue_work(system_unbound_wq,
5170                                            &root->fs_info->async_reclaim_work);
5171                         }
5172                 } else {
5173                         list_add_tail(&ticket.list,
5174                                       &space_info->priority_tickets);
5175                 }
5176         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5177                 used += orig_bytes;
5178                 /*
5179                  * We will do the space reservation dance during log replay,
5180                  * which means we won't have fs_info->fs_root set, so don't do
5181                  * the async reclaim as we will panic.
5182                  */
5183                 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &root->fs_info->flags) &&
5184                     need_do_async_reclaim(space_info, root, used) &&
5185                     !work_busy(&root->fs_info->async_reclaim_work)) {
5186                         trace_btrfs_trigger_flush(root->fs_info,
5187                                                   space_info->flags,
5188                                                   orig_bytes, flush,
5189                                                   "preempt");
5190                         queue_work(system_unbound_wq,
5191                                    &root->fs_info->async_reclaim_work);
5192                 }
5193         }
5194         spin_unlock(&space_info->lock);
5195         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5196                 return ret;
5197
5198         if (flush == BTRFS_RESERVE_FLUSH_ALL)
5199                 return wait_reserve_ticket(root->fs_info, space_info, &ticket,
5200                                            orig_bytes);
5201
5202         ret = 0;
5203         priority_reclaim_metadata_space(root->fs_info, space_info, &ticket);
5204         spin_lock(&space_info->lock);
5205         if (ticket.bytes) {
5206                 if (ticket.bytes < orig_bytes) {
5207                         u64 num_bytes = orig_bytes - ticket.bytes;
5208                         space_info->bytes_may_use -= num_bytes;
5209                         trace_btrfs_space_reservation(root->fs_info,
5210                                         "space_info", space_info->flags,
5211                                         num_bytes, 0);
5212
5213                 }
5214                 list_del_init(&ticket.list);
5215                 ret = -ENOSPC;
5216         }
5217         spin_unlock(&space_info->lock);
5218         ASSERT(list_empty(&ticket.list));
5219         return ret;
5220 }
5221
5222 /**
5223  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5224  * @root - the root we're allocating for
5225  * @block_rsv - the block_rsv we're allocating for
5226  * @orig_bytes - the number of bytes we want
5227  * @flush - whether or not we can flush to make our reservation
5228  *
5229  * This will reserve orgi_bytes number of bytes from the space info associated
5230  * with the block_rsv.  If there is not enough space it will make an attempt to
5231  * flush out space to make room.  It will do this by flushing delalloc if
5232  * possible or committing the transaction.  If flush is 0 then no attempts to
5233  * regain reservations will be made and this will fail if there is not enough
5234  * space already.
5235  */
5236 static int reserve_metadata_bytes(struct btrfs_root *root,
5237                                   struct btrfs_block_rsv *block_rsv,
5238                                   u64 orig_bytes,
5239                                   enum btrfs_reserve_flush_enum flush)
5240 {
5241         int ret;
5242
5243         ret = __reserve_metadata_bytes(root, block_rsv->space_info, orig_bytes,
5244                                        flush);
5245         if (ret == -ENOSPC &&
5246             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5247                 struct btrfs_block_rsv *global_rsv =
5248                         &root->fs_info->global_block_rsv;
5249
5250                 if (block_rsv != global_rsv &&
5251                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5252                         ret = 0;
5253         }
5254         if (ret == -ENOSPC)
5255                 trace_btrfs_space_reservation(root->fs_info,
5256                                               "space_info:enospc",
5257                                               block_rsv->space_info->flags,
5258                                               orig_bytes, 1);
5259         return ret;
5260 }
5261
5262 static struct btrfs_block_rsv *get_block_rsv(
5263                                         const struct btrfs_trans_handle *trans,
5264                                         const struct btrfs_root *root)
5265 {
5266         struct btrfs_block_rsv *block_rsv = NULL;
5267
5268         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5269             (root == root->fs_info->csum_root && trans->adding_csums) ||
5270              (root == root->fs_info->uuid_root))
5271                 block_rsv = trans->block_rsv;
5272
5273         if (!block_rsv)
5274                 block_rsv = root->block_rsv;
5275
5276         if (!block_rsv)
5277                 block_rsv = &root->fs_info->empty_block_rsv;
5278
5279         return block_rsv;
5280 }
5281
5282 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5283                                u64 num_bytes)
5284 {
5285         int ret = -ENOSPC;
5286         spin_lock(&block_rsv->lock);
5287         if (block_rsv->reserved >= num_bytes) {
5288                 block_rsv->reserved -= num_bytes;
5289                 if (block_rsv->reserved < block_rsv->size)
5290                         block_rsv->full = 0;
5291                 ret = 0;
5292         }
5293         spin_unlock(&block_rsv->lock);
5294         return ret;
5295 }
5296
5297 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5298                                 u64 num_bytes, int update_size)
5299 {
5300         spin_lock(&block_rsv->lock);
5301         block_rsv->reserved += num_bytes;
5302         if (update_size)
5303                 block_rsv->size += num_bytes;
5304         else if (block_rsv->reserved >= block_rsv->size)
5305                 block_rsv->full = 1;
5306         spin_unlock(&block_rsv->lock);
5307 }
5308
5309 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5310                              struct btrfs_block_rsv *dest, u64 num_bytes,
5311                              int min_factor)
5312 {
5313         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5314         u64 min_bytes;
5315
5316         if (global_rsv->space_info != dest->space_info)
5317                 return -ENOSPC;
5318
5319         spin_lock(&global_rsv->lock);
5320         min_bytes = div_factor(global_rsv->size, min_factor);
5321         if (global_rsv->reserved < min_bytes + num_bytes) {
5322                 spin_unlock(&global_rsv->lock);
5323                 return -ENOSPC;
5324         }
5325         global_rsv->reserved -= num_bytes;
5326         if (global_rsv->reserved < global_rsv->size)
5327                 global_rsv->full = 0;
5328         spin_unlock(&global_rsv->lock);
5329
5330         block_rsv_add_bytes(dest, num_bytes, 1);
5331         return 0;
5332 }
5333
5334 /*
5335  * This is for space we already have accounted in space_info->bytes_may_use, so
5336  * basically when we're returning space from block_rsv's.
5337  */
5338 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5339                                      struct btrfs_space_info *space_info,
5340                                      u64 num_bytes)
5341 {
5342         struct reserve_ticket *ticket;
5343         struct list_head *head;
5344         u64 used;
5345         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5346         bool check_overcommit = false;
5347
5348         spin_lock(&space_info->lock);
5349         head = &space_info->priority_tickets;
5350
5351         /*
5352          * If we are over our limit then we need to check and see if we can
5353          * overcommit, and if we can't then we just need to free up our space
5354          * and not satisfy any requests.
5355          */
5356         used = space_info->bytes_used + space_info->bytes_reserved +
5357                 space_info->bytes_pinned + space_info->bytes_readonly +
5358                 space_info->bytes_may_use;
5359         if (used - num_bytes >= space_info->total_bytes)
5360                 check_overcommit = true;
5361 again:
5362         while (!list_empty(head) && num_bytes) {
5363                 ticket = list_first_entry(head, struct reserve_ticket,
5364                                           list);
5365                 /*
5366                  * We use 0 bytes because this space is already reserved, so
5367                  * adding the ticket space would be a double count.
5368                  */
5369                 if (check_overcommit &&
5370                     !can_overcommit(fs_info->extent_root, space_info, 0,
5371                                     flush))
5372                         break;
5373                 if (num_bytes >= ticket->bytes) {
5374                         list_del_init(&ticket->list);
5375                         num_bytes -= ticket->bytes;
5376                         ticket->bytes = 0;
5377                         space_info->tickets_id++;
5378                         wake_up(&ticket->wait);
5379                 } else {
5380                         ticket->bytes -= num_bytes;
5381                         num_bytes = 0;
5382                 }
5383         }
5384
5385         if (num_bytes && head == &space_info->priority_tickets) {
5386                 head = &space_info->tickets;
5387                 flush = BTRFS_RESERVE_FLUSH_ALL;
5388                 goto again;
5389         }
5390         space_info->bytes_may_use -= num_bytes;
5391         trace_btrfs_space_reservation(fs_info, "space_info",
5392                                       space_info->flags, num_bytes, 0);
5393         spin_unlock(&space_info->lock);
5394 }
5395
5396 /*
5397  * This is for newly allocated space that isn't accounted in
5398  * space_info->bytes_may_use yet.  So if we allocate a chunk or unpin an extent
5399  * we use this helper.
5400  */
5401 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5402                                      struct btrfs_space_info *space_info,
5403                                      u64 num_bytes)
5404 {
5405         struct reserve_ticket *ticket;
5406         struct list_head *head = &space_info->priority_tickets;
5407
5408 again:
5409         while (!list_empty(head) && num_bytes) {
5410                 ticket = list_first_entry(head, struct reserve_ticket,
5411                                           list);
5412                 if (num_bytes >= ticket->bytes) {
5413                         trace_btrfs_space_reservation(fs_info, "space_info",
5414                                                       space_info->flags,
5415                                                       ticket->bytes, 1);
5416                         list_del_init(&ticket->list);
5417                         num_bytes -= ticket->bytes;
5418                         space_info->bytes_may_use += ticket->bytes;
5419                         ticket->bytes = 0;
5420                         space_info->tickets_id++;
5421                         wake_up(&ticket->wait);
5422                 } else {
5423                         trace_btrfs_space_reservation(fs_info, "space_info",
5424                                                       space_info->flags,
5425                                                       num_bytes, 1);
5426                         space_info->bytes_may_use += num_bytes;
5427                         ticket->bytes -= num_bytes;
5428                         num_bytes = 0;
5429                 }
5430         }
5431
5432         if (num_bytes && head == &space_info->priority_tickets) {
5433                 head = &space_info->tickets;
5434                 goto again;
5435         }
5436 }
5437
5438 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5439                                     struct btrfs_block_rsv *block_rsv,
5440                                     struct btrfs_block_rsv *dest, u64 num_bytes)
5441 {
5442         struct btrfs_space_info *space_info = block_rsv->space_info;
5443
5444         spin_lock(&block_rsv->lock);
5445         if (num_bytes == (u64)-1)
5446                 num_bytes = block_rsv->size;
5447         block_rsv->size -= num_bytes;
5448         if (block_rsv->reserved >= block_rsv->size) {
5449                 num_bytes = block_rsv->reserved - block_rsv->size;
5450                 block_rsv->reserved = block_rsv->size;
5451                 block_rsv->full = 1;
5452         } else {
5453                 num_bytes = 0;
5454         }
5455         spin_unlock(&block_rsv->lock);
5456
5457         if (num_bytes > 0) {
5458                 if (dest) {
5459                         spin_lock(&dest->lock);
5460                         if (!dest->full) {
5461                                 u64 bytes_to_add;
5462
5463                                 bytes_to_add = dest->size - dest->reserved;
5464                                 bytes_to_add = min(num_bytes, bytes_to_add);
5465                                 dest->reserved += bytes_to_add;
5466                                 if (dest->reserved >= dest->size)
5467                                         dest->full = 1;
5468                                 num_bytes -= bytes_to_add;
5469                         }
5470                         spin_unlock(&dest->lock);
5471                 }
5472                 if (num_bytes)
5473                         space_info_add_old_bytes(fs_info, space_info,
5474                                                  num_bytes);
5475         }
5476 }
5477
5478 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5479                             struct btrfs_block_rsv *dst, u64 num_bytes,
5480                             int update_size)
5481 {
5482         int ret;
5483
5484         ret = block_rsv_use_bytes(src, num_bytes);
5485         if (ret)
5486                 return ret;
5487
5488         block_rsv_add_bytes(dst, num_bytes, update_size);
5489         return 0;
5490 }
5491
5492 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5493 {
5494         memset(rsv, 0, sizeof(*rsv));
5495         spin_lock_init(&rsv->lock);
5496         rsv->type = type;
5497 }
5498
5499 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
5500                                               unsigned short type)
5501 {
5502         struct btrfs_block_rsv *block_rsv;
5503         struct btrfs_fs_info *fs_info = root->fs_info;
5504
5505         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5506         if (!block_rsv)
5507                 return NULL;
5508
5509         btrfs_init_block_rsv(block_rsv, type);
5510         block_rsv->space_info = __find_space_info(fs_info,
5511                                                   BTRFS_BLOCK_GROUP_METADATA);
5512         return block_rsv;
5513 }
5514
5515 void btrfs_free_block_rsv(struct btrfs_root *root,
5516                           struct btrfs_block_rsv *rsv)
5517 {
5518         if (!rsv)
5519                 return;
5520         btrfs_block_rsv_release(root, rsv, (u64)-1);
5521         kfree(rsv);
5522 }
5523
5524 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5525 {
5526         kfree(rsv);
5527 }
5528
5529 int btrfs_block_rsv_add(struct btrfs_root *root,
5530                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5531                         enum btrfs_reserve_flush_enum flush)
5532 {
5533         int ret;
5534
5535         if (num_bytes == 0)
5536                 return 0;
5537
5538         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5539         if (!ret) {
5540                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5541                 return 0;
5542         }
5543
5544         return ret;
5545 }
5546
5547 int btrfs_block_rsv_check(struct btrfs_root *root,
5548                           struct btrfs_block_rsv *block_rsv, int min_factor)
5549 {
5550         u64 num_bytes = 0;
5551         int ret = -ENOSPC;
5552
5553         if (!block_rsv)
5554                 return 0;
5555
5556         spin_lock(&block_rsv->lock);
5557         num_bytes = div_factor(block_rsv->size, min_factor);
5558         if (block_rsv->reserved >= num_bytes)
5559                 ret = 0;
5560         spin_unlock(&block_rsv->lock);
5561
5562         return ret;
5563 }
5564
5565 int btrfs_block_rsv_refill(struct btrfs_root *root,
5566                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5567                            enum btrfs_reserve_flush_enum flush)
5568 {
5569         u64 num_bytes = 0;
5570         int ret = -ENOSPC;
5571
5572         if (!block_rsv)
5573                 return 0;
5574
5575         spin_lock(&block_rsv->lock);
5576         num_bytes = min_reserved;
5577         if (block_rsv->reserved >= num_bytes)
5578                 ret = 0;
5579         else
5580                 num_bytes -= block_rsv->reserved;
5581         spin_unlock(&block_rsv->lock);
5582
5583         if (!ret)
5584                 return 0;
5585
5586         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5587         if (!ret) {
5588                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5589                 return 0;
5590         }
5591
5592         return ret;
5593 }
5594
5595 void btrfs_block_rsv_release(struct btrfs_root *root,
5596                              struct btrfs_block_rsv *block_rsv,
5597                              u64 num_bytes)
5598 {
5599         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5600         if (global_rsv == block_rsv ||
5601             block_rsv->space_info != global_rsv->space_info)
5602                 global_rsv = NULL;
5603         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5604                                 num_bytes);
5605 }
5606
5607 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5608 {
5609         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5610         struct btrfs_space_info *sinfo = block_rsv->space_info;
5611         u64 num_bytes;
5612
5613         /*
5614          * The global block rsv is based on the size of the extent tree, the
5615          * checksum tree and the root tree.  If the fs is empty we want to set
5616          * it to a minimal amount for safety.
5617          */
5618         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5619                 btrfs_root_used(&fs_info->csum_root->root_item) +
5620                 btrfs_root_used(&fs_info->tree_root->root_item);
5621         num_bytes = max_t(u64, num_bytes, SZ_16M);
5622
5623         spin_lock(&sinfo->lock);
5624         spin_lock(&block_rsv->lock);
5625
5626         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5627
5628         if (block_rsv->reserved < block_rsv->size) {
5629                 num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5630                         sinfo->bytes_reserved + sinfo->bytes_readonly +
5631                         sinfo->bytes_may_use;
5632                 if (sinfo->total_bytes > num_bytes) {
5633                         num_bytes = sinfo->total_bytes - num_bytes;
5634                         num_bytes = min(num_bytes,
5635                                         block_rsv->size - block_rsv->reserved);
5636                         block_rsv->reserved += num_bytes;
5637                         sinfo->bytes_may_use += num_bytes;
5638                         trace_btrfs_space_reservation(fs_info, "space_info",
5639                                                       sinfo->flags, num_bytes,
5640                                                       1);
5641                 }
5642         } else if (block_rsv->reserved > block_rsv->size) {
5643                 num_bytes = block_rsv->reserved - block_rsv->size;
5644                 sinfo->bytes_may_use -= num_bytes;
5645                 trace_btrfs_space_reservation(fs_info, "space_info",
5646                                       sinfo->flags, num_bytes, 0);
5647                 block_rsv->reserved = block_rsv->size;
5648         }
5649
5650         if (block_rsv->reserved == block_rsv->size)
5651                 block_rsv->full = 1;
5652         else
5653                 block_rsv->full = 0;
5654
5655         spin_unlock(&block_rsv->lock);
5656         spin_unlock(&sinfo->lock);
5657 }
5658
5659 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5660 {
5661         struct btrfs_space_info *space_info;
5662
5663         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5664         fs_info->chunk_block_rsv.space_info = space_info;
5665
5666         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5667         fs_info->global_block_rsv.space_info = space_info;
5668         fs_info->delalloc_block_rsv.space_info = space_info;
5669         fs_info->trans_block_rsv.space_info = space_info;
5670         fs_info->empty_block_rsv.space_info = space_info;
5671         fs_info->delayed_block_rsv.space_info = space_info;
5672
5673         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5674         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5675         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5676         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5677         if (fs_info->quota_root)
5678                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5679         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5680
5681         update_global_block_rsv(fs_info);
5682 }
5683
5684 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5685 {
5686         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5687                                 (u64)-1);
5688         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5689         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5690         WARN_ON(fs_info->trans_block_rsv.size > 0);
5691         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5692         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5693         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5694         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5695         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5696 }
5697
5698 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5699                                   struct btrfs_root *root)
5700 {
5701         if (!trans->block_rsv)
5702                 return;
5703
5704         if (!trans->bytes_reserved)
5705                 return;
5706
5707         trace_btrfs_space_reservation(root->fs_info, "transaction",
5708                                       trans->transid, trans->bytes_reserved, 0);
5709         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5710         trans->bytes_reserved = 0;
5711 }
5712
5713 /*
5714  * To be called after all the new block groups attached to the transaction
5715  * handle have been created (btrfs_create_pending_block_groups()).
5716  */
5717 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5718 {
5719         struct btrfs_fs_info *fs_info = trans->fs_info;
5720
5721         if (!trans->chunk_bytes_reserved)
5722                 return;
5723
5724         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5725
5726         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5727                                 trans->chunk_bytes_reserved);
5728         trans->chunk_bytes_reserved = 0;
5729 }
5730
5731 /* Can only return 0 or -ENOSPC */
5732 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5733                                   struct inode *inode)
5734 {
5735         struct btrfs_root *root = BTRFS_I(inode)->root;
5736         /*
5737          * We always use trans->block_rsv here as we will have reserved space
5738          * for our orphan when starting the transaction, using get_block_rsv()
5739          * here will sometimes make us choose the wrong block rsv as we could be
5740          * doing a reloc inode for a non refcounted root.
5741          */
5742         struct btrfs_block_rsv *src_rsv = trans->block_rsv;
5743         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5744
5745         /*
5746          * We need to hold space in order to delete our orphan item once we've
5747          * added it, so this takes the reservation so we can release it later
5748          * when we are truly done with the orphan item.
5749          */
5750         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5751         trace_btrfs_space_reservation(root->fs_info, "orphan",
5752                                       btrfs_ino(inode), num_bytes, 1);
5753         return btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
5754 }
5755
5756 void btrfs_orphan_release_metadata(struct inode *inode)
5757 {
5758         struct btrfs_root *root = BTRFS_I(inode)->root;
5759         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5760         trace_btrfs_space_reservation(root->fs_info, "orphan",
5761                                       btrfs_ino(inode), num_bytes, 0);
5762         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5763 }
5764
5765 /*
5766  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5767  * root: the root of the parent directory
5768  * rsv: block reservation
5769  * items: the number of items that we need do reservation
5770  * qgroup_reserved: used to return the reserved size in qgroup
5771  *
5772  * This function is used to reserve the space for snapshot/subvolume
5773  * creation and deletion. Those operations are different with the
5774  * common file/directory operations, they change two fs/file trees
5775  * and root tree, the number of items that the qgroup reserves is
5776  * different with the free space reservation. So we can not use
5777  * the space reservation mechanism in start_transaction().
5778  */
5779 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5780                                      struct btrfs_block_rsv *rsv,
5781                                      int items,
5782                                      u64 *qgroup_reserved,
5783                                      bool use_global_rsv)
5784 {
5785         u64 num_bytes;
5786         int ret;
5787         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5788
5789         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags)) {
5790                 /* One for parent inode, two for dir entries */
5791                 num_bytes = 3 * root->nodesize;
5792                 ret = btrfs_qgroup_reserve_meta(root, num_bytes);
5793                 if (ret)
5794                         return ret;
5795         } else {
5796                 num_bytes = 0;
5797         }
5798
5799         *qgroup_reserved = num_bytes;
5800
5801         num_bytes = btrfs_calc_trans_metadata_size(root, items);
5802         rsv->space_info = __find_space_info(root->fs_info,
5803                                             BTRFS_BLOCK_GROUP_METADATA);
5804         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5805                                   BTRFS_RESERVE_FLUSH_ALL);
5806
5807         if (ret == -ENOSPC && use_global_rsv)
5808                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5809
5810         if (ret && *qgroup_reserved)
5811                 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5812
5813         return ret;
5814 }
5815
5816 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5817                                       struct btrfs_block_rsv *rsv,
5818                                       u64 qgroup_reserved)
5819 {
5820         btrfs_block_rsv_release(root, rsv, (u64)-1);
5821 }
5822
5823 /**
5824  * drop_outstanding_extent - drop an outstanding extent
5825  * @inode: the inode we're dropping the extent for
5826  * @num_bytes: the number of bytes we're releasing.
5827  *
5828  * This is called when we are freeing up an outstanding extent, either called
5829  * after an error or after an extent is written.  This will return the number of
5830  * reserved extents that need to be freed.  This must be called with
5831  * BTRFS_I(inode)->lock held.
5832  */
5833 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5834 {
5835         unsigned drop_inode_space = 0;
5836         unsigned dropped_extents = 0;
5837         unsigned num_extents = 0;
5838
5839         num_extents = (unsigned)div64_u64(num_bytes +
5840                                           BTRFS_MAX_EXTENT_SIZE - 1,
5841                                           BTRFS_MAX_EXTENT_SIZE);
5842         ASSERT(num_extents);
5843         ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5844         BTRFS_I(inode)->outstanding_extents -= num_extents;
5845
5846         if (BTRFS_I(inode)->outstanding_extents == 0 &&
5847             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5848                                &BTRFS_I(inode)->runtime_flags))
5849                 drop_inode_space = 1;
5850
5851         /*
5852          * If we have more or the same amount of outstanding extents than we have
5853          * reserved then we need to leave the reserved extents count alone.
5854          */
5855         if (BTRFS_I(inode)->outstanding_extents >=
5856             BTRFS_I(inode)->reserved_extents)
5857                 return drop_inode_space;
5858
5859         dropped_extents = BTRFS_I(inode)->reserved_extents -
5860                 BTRFS_I(inode)->outstanding_extents;
5861         BTRFS_I(inode)->reserved_extents -= dropped_extents;
5862         return dropped_extents + drop_inode_space;
5863 }
5864
5865 /**
5866  * calc_csum_metadata_size - return the amount of metadata space that must be
5867  *      reserved/freed for the given bytes.
5868  * @inode: the inode we're manipulating
5869  * @num_bytes: the number of bytes in question
5870  * @reserve: 1 if we are reserving space, 0 if we are freeing space
5871  *
5872  * This adjusts the number of csum_bytes in the inode and then returns the
5873  * correct amount of metadata that must either be reserved or freed.  We
5874  * calculate how many checksums we can fit into one leaf and then divide the
5875  * number of bytes that will need to be checksumed by this value to figure out
5876  * how many checksums will be required.  If we are adding bytes then the number
5877  * may go up and we will return the number of additional bytes that must be
5878  * reserved.  If it is going down we will return the number of bytes that must
5879  * be freed.
5880  *
5881  * This must be called with BTRFS_I(inode)->lock held.
5882  */
5883 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5884                                    int reserve)
5885 {
5886         struct btrfs_root *root = BTRFS_I(inode)->root;
5887         u64 old_csums, num_csums;
5888
5889         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5890             BTRFS_I(inode)->csum_bytes == 0)
5891                 return 0;
5892
5893         old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5894         if (reserve)
5895                 BTRFS_I(inode)->csum_bytes += num_bytes;
5896         else
5897                 BTRFS_I(inode)->csum_bytes -= num_bytes;
5898         num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5899
5900         /* No change, no need to reserve more */
5901         if (old_csums == num_csums)
5902                 return 0;
5903
5904         if (reserve)
5905                 return btrfs_calc_trans_metadata_size(root,
5906                                                       num_csums - old_csums);
5907
5908         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5909 }
5910
5911 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5912 {
5913         struct btrfs_root *root = BTRFS_I(inode)->root;
5914         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5915         u64 to_reserve = 0;
5916         u64 csum_bytes;
5917         unsigned nr_extents = 0;
5918         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5919         int ret = 0;
5920         bool delalloc_lock = true;
5921         u64 to_free = 0;
5922         unsigned dropped;
5923         bool release_extra = false;
5924
5925         /* If we are a free space inode we need to not flush since we will be in
5926          * the middle of a transaction commit.  We also don't need the delalloc
5927          * mutex since we won't race with anybody.  We need this mostly to make
5928          * lockdep shut its filthy mouth.
5929          *
5930          * If we have a transaction open (can happen if we call truncate_block
5931          * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
5932          */
5933         if (btrfs_is_free_space_inode(inode)) {
5934                 flush = BTRFS_RESERVE_NO_FLUSH;
5935                 delalloc_lock = false;
5936         } else if (current->journal_info) {
5937                 flush = BTRFS_RESERVE_FLUSH_LIMIT;
5938         }
5939
5940         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5941             btrfs_transaction_in_commit(root->fs_info))
5942                 schedule_timeout(1);
5943
5944         if (delalloc_lock)
5945                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5946
5947         num_bytes = ALIGN(num_bytes, root->sectorsize);
5948
5949         spin_lock(&BTRFS_I(inode)->lock);
5950         nr_extents = (unsigned)div64_u64(num_bytes +
5951                                          BTRFS_MAX_EXTENT_SIZE - 1,
5952                                          BTRFS_MAX_EXTENT_SIZE);
5953         BTRFS_I(inode)->outstanding_extents += nr_extents;
5954
5955         nr_extents = 0;
5956         if (BTRFS_I(inode)->outstanding_extents >
5957             BTRFS_I(inode)->reserved_extents)
5958                 nr_extents += BTRFS_I(inode)->outstanding_extents -
5959                         BTRFS_I(inode)->reserved_extents;
5960
5961         /* We always want to reserve a slot for updating the inode. */
5962         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents + 1);
5963         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5964         csum_bytes = BTRFS_I(inode)->csum_bytes;
5965         spin_unlock(&BTRFS_I(inode)->lock);
5966
5967         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags)) {
5968                 ret = btrfs_qgroup_reserve_meta(root,
5969                                 nr_extents * root->nodesize);
5970                 if (ret)
5971                         goto out_fail;
5972         }
5973
5974         ret = btrfs_block_rsv_add(root, block_rsv, to_reserve, flush);
5975         if (unlikely(ret)) {
5976                 btrfs_qgroup_free_meta(root, nr_extents * root->nodesize);
5977                 goto out_fail;
5978         }
5979
5980         spin_lock(&BTRFS_I(inode)->lock);
5981         if (test_and_set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5982                              &BTRFS_I(inode)->runtime_flags)) {
5983                 to_reserve -= btrfs_calc_trans_metadata_size(root, 1);
5984                 release_extra = true;
5985         }
5986         BTRFS_I(inode)->reserved_extents += nr_extents;
5987         spin_unlock(&BTRFS_I(inode)->lock);
5988
5989         if (delalloc_lock)
5990                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5991
5992         if (to_reserve)
5993                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5994                                               btrfs_ino(inode), to_reserve, 1);
5995         if (release_extra)
5996                 btrfs_block_rsv_release(root, block_rsv,
5997                                         btrfs_calc_trans_metadata_size(root,
5998                                                                        1));
5999         return 0;
6000
6001 out_fail:
6002         spin_lock(&BTRFS_I(inode)->lock);
6003         dropped = drop_outstanding_extent(inode, num_bytes);
6004         /*
6005          * If the inodes csum_bytes is the same as the original
6006          * csum_bytes then we know we haven't raced with any free()ers
6007          * so we can just reduce our inodes csum bytes and carry on.
6008          */
6009         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
6010                 calc_csum_metadata_size(inode, num_bytes, 0);
6011         } else {
6012                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
6013                 u64 bytes;
6014
6015                 /*
6016                  * This is tricky, but first we need to figure out how much we
6017                  * freed from any free-ers that occurred during this
6018                  * reservation, so we reset ->csum_bytes to the csum_bytes
6019                  * before we dropped our lock, and then call the free for the
6020                  * number of bytes that were freed while we were trying our
6021                  * reservation.
6022                  */
6023                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
6024                 BTRFS_I(inode)->csum_bytes = csum_bytes;
6025                 to_free = calc_csum_metadata_size(inode, bytes, 0);
6026
6027
6028                 /*
6029                  * Now we need to see how much we would have freed had we not
6030                  * been making this reservation and our ->csum_bytes were not
6031                  * artificially inflated.
6032                  */
6033                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
6034                 bytes = csum_bytes - orig_csum_bytes;
6035                 bytes = calc_csum_metadata_size(inode, bytes, 0);
6036
6037                 /*
6038                  * Now reset ->csum_bytes to what it should be.  If bytes is
6039                  * more than to_free then we would have freed more space had we
6040                  * not had an artificially high ->csum_bytes, so we need to free
6041                  * the remainder.  If bytes is the same or less then we don't
6042                  * need to do anything, the other free-ers did the correct
6043                  * thing.
6044                  */
6045                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
6046                 if (bytes > to_free)
6047                         to_free = bytes - to_free;
6048                 else
6049                         to_free = 0;
6050         }
6051         spin_unlock(&BTRFS_I(inode)->lock);
6052         if (dropped)
6053                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6054
6055         if (to_free) {
6056                 btrfs_block_rsv_release(root, block_rsv, to_free);
6057                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
6058                                               btrfs_ino(inode), to_free, 0);
6059         }
6060         if (delalloc_lock)
6061                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
6062         return ret;
6063 }
6064
6065 /**
6066  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
6067  * @inode: the inode to release the reservation for
6068  * @num_bytes: the number of bytes we're releasing
6069  *
6070  * This will release the metadata reservation for an inode.  This can be called
6071  * once we complete IO for a given set of bytes to release their metadata
6072  * reservations.
6073  */
6074 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
6075 {
6076         struct btrfs_root *root = BTRFS_I(inode)->root;
6077         u64 to_free = 0;
6078         unsigned dropped;
6079
6080         num_bytes = ALIGN(num_bytes, root->sectorsize);
6081         spin_lock(&BTRFS_I(inode)->lock);
6082         dropped = drop_outstanding_extent(inode, num_bytes);
6083
6084         if (num_bytes)
6085                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
6086         spin_unlock(&BTRFS_I(inode)->lock);
6087         if (dropped > 0)
6088                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
6089
6090         if (btrfs_is_testing(root->fs_info))
6091                 return;
6092
6093         trace_btrfs_space_reservation(root->fs_info, "delalloc",
6094                                       btrfs_ino(inode), to_free, 0);
6095
6096         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
6097                                 to_free);
6098 }
6099
6100 /**
6101  * btrfs_delalloc_reserve_space - reserve data and metadata space for
6102  * delalloc
6103  * @inode: inode we're writing to
6104  * @start: start range we are writing to
6105  * @len: how long the range we are writing to
6106  *
6107  * TODO: This function will finally replace old btrfs_delalloc_reserve_space()
6108  *
6109  * This will do the following things
6110  *
6111  * o reserve space in data space info for num bytes
6112  *   and reserve precious corresponding qgroup space
6113  *   (Done in check_data_free_space)
6114  *
6115  * o reserve space for metadata space, based on the number of outstanding
6116  *   extents and how much csums will be needed
6117  *   also reserve metadata space in a per root over-reserve method.
6118  * o add to the inodes->delalloc_bytes
6119  * o add it to the fs_info's delalloc inodes list.
6120  *   (Above 3 all done in delalloc_reserve_metadata)
6121  *
6122  * Return 0 for success
6123  * Return <0 for error(-ENOSPC or -EQUOT)
6124  */
6125 int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
6126 {
6127         int ret;
6128
6129         ret = btrfs_check_data_free_space(inode, start, len);
6130         if (ret < 0)
6131                 return ret;
6132         ret = btrfs_delalloc_reserve_metadata(inode, len);
6133         if (ret < 0)
6134                 btrfs_free_reserved_data_space(inode, start, len);
6135         return ret;
6136 }
6137
6138 /**
6139  * btrfs_delalloc_release_space - release data and metadata space for delalloc
6140  * @inode: inode we're releasing space for
6141  * @start: start position of the space already reserved
6142  * @len: the len of the space already reserved
6143  *
6144  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
6145  * called in the case that we don't need the metadata AND data reservations
6146  * anymore.  So if there is an error or we insert an inline extent.
6147  *
6148  * This function will release the metadata space that was not used and will
6149  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6150  * list if there are no delalloc bytes left.
6151  * Also it will handle the qgroup reserved space.
6152  */
6153 void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len)
6154 {
6155         btrfs_delalloc_release_metadata(inode, len);
6156         btrfs_free_reserved_data_space(inode, start, len);
6157 }
6158
6159 static int update_block_group(struct btrfs_trans_handle *trans,
6160                               struct btrfs_root *root, u64 bytenr,
6161                               u64 num_bytes, int alloc)
6162 {
6163         struct btrfs_block_group_cache *cache = NULL;
6164         struct btrfs_fs_info *info = root->fs_info;
6165         u64 total = num_bytes;
6166         u64 old_val;
6167         u64 byte_in_group;
6168         int factor;
6169
6170         /* block accounting for super block */
6171         spin_lock(&info->delalloc_root_lock);
6172         old_val = btrfs_super_bytes_used(info->super_copy);
6173         if (alloc)
6174                 old_val += num_bytes;
6175         else
6176                 old_val -= num_bytes;
6177         btrfs_set_super_bytes_used(info->super_copy, old_val);
6178         spin_unlock(&info->delalloc_root_lock);
6179
6180         while (total) {
6181                 cache = btrfs_lookup_block_group(info, bytenr);
6182                 if (!cache)
6183                         return -ENOENT;
6184                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6185                                     BTRFS_BLOCK_GROUP_RAID1 |
6186                                     BTRFS_BLOCK_GROUP_RAID10))
6187                         factor = 2;
6188                 else
6189                         factor = 1;
6190                 /*
6191                  * If this block group has free space cache written out, we
6192                  * need to make sure to load it if we are removing space.  This
6193                  * is because we need the unpinning stage to actually add the
6194                  * space back to the block group, otherwise we will leak space.
6195                  */
6196                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6197                         cache_block_group(cache, 1);
6198
6199                 byte_in_group = bytenr - cache->key.objectid;
6200                 WARN_ON(byte_in_group > cache->key.offset);
6201
6202                 spin_lock(&cache->space_info->lock);
6203                 spin_lock(&cache->lock);
6204
6205                 if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
6206                     cache->disk_cache_state < BTRFS_DC_CLEAR)
6207                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6208
6209                 old_val = btrfs_block_group_used(&cache->item);
6210                 num_bytes = min(total, cache->key.offset - byte_in_group);
6211                 if (alloc) {
6212                         old_val += num_bytes;
6213                         btrfs_set_block_group_used(&cache->item, old_val);
6214                         cache->reserved -= num_bytes;
6215                         cache->space_info->bytes_reserved -= num_bytes;
6216                         cache->space_info->bytes_used += num_bytes;
6217                         cache->space_info->disk_used += num_bytes * factor;
6218                         spin_unlock(&cache->lock);
6219                         spin_unlock(&cache->space_info->lock);
6220                 } else {
6221                         old_val -= num_bytes;
6222                         btrfs_set_block_group_used(&cache->item, old_val);
6223                         cache->pinned += num_bytes;
6224                         cache->space_info->bytes_pinned += num_bytes;
6225                         cache->space_info->bytes_used -= num_bytes;
6226                         cache->space_info->disk_used -= num_bytes * factor;
6227                         spin_unlock(&cache->lock);
6228                         spin_unlock(&cache->space_info->lock);
6229
6230                         trace_btrfs_space_reservation(root->fs_info, "pinned",
6231                                                       cache->space_info->flags,
6232                                                       num_bytes, 1);
6233                         set_extent_dirty(info->pinned_extents,
6234                                          bytenr, bytenr + num_bytes - 1,
6235                                          GFP_NOFS | __GFP_NOFAIL);
6236                 }
6237
6238                 spin_lock(&trans->transaction->dirty_bgs_lock);
6239                 if (list_empty(&cache->dirty_list)) {
6240                         list_add_tail(&cache->dirty_list,
6241                                       &trans->transaction->dirty_bgs);
6242                                 trans->transaction->num_dirty_bgs++;
6243                         btrfs_get_block_group(cache);
6244                 }
6245                 spin_unlock(&trans->transaction->dirty_bgs_lock);
6246
6247                 /*
6248                  * No longer have used bytes in this block group, queue it for
6249                  * deletion. We do this after adding the block group to the
6250                  * dirty list to avoid races between cleaner kthread and space
6251                  * cache writeout.
6252                  */
6253                 if (!alloc && old_val == 0) {
6254                         spin_lock(&info->unused_bgs_lock);
6255                         if (list_empty(&cache->bg_list)) {
6256                                 btrfs_get_block_group(cache);
6257                                 list_add_tail(&cache->bg_list,
6258                                               &info->unused_bgs);
6259                         }
6260                         spin_unlock(&info->unused_bgs_lock);
6261                 }
6262
6263                 btrfs_put_block_group(cache);
6264                 total -= num_bytes;
6265                 bytenr += num_bytes;
6266         }
6267         return 0;
6268 }
6269
6270 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
6271 {
6272         struct btrfs_block_group_cache *cache;
6273         u64 bytenr;
6274
6275         spin_lock(&root->fs_info->block_group_cache_lock);
6276         bytenr = root->fs_info->first_logical_byte;
6277         spin_unlock(&root->fs_info->block_group_cache_lock);
6278
6279         if (bytenr < (u64)-1)
6280                 return bytenr;
6281
6282         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
6283         if (!cache)
6284                 return 0;
6285
6286         bytenr = cache->key.objectid;
6287         btrfs_put_block_group(cache);
6288
6289         return bytenr;
6290 }
6291
6292 static int pin_down_extent(struct btrfs_root *root,
6293                            struct btrfs_block_group_cache *cache,
6294                            u64 bytenr, u64 num_bytes, int reserved)
6295 {
6296         spin_lock(&cache->space_info->lock);
6297         spin_lock(&cache->lock);
6298         cache->pinned += num_bytes;
6299         cache->space_info->bytes_pinned += num_bytes;
6300         if (reserved) {
6301                 cache->reserved -= num_bytes;
6302                 cache->space_info->bytes_reserved -= num_bytes;
6303         }
6304         spin_unlock(&cache->lock);
6305         spin_unlock(&cache->space_info->lock);
6306
6307         trace_btrfs_space_reservation(root->fs_info, "pinned",
6308                                       cache->space_info->flags, num_bytes, 1);
6309         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
6310                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6311         return 0;
6312 }
6313
6314 /*
6315  * this function must be called within transaction
6316  */
6317 int btrfs_pin_extent(struct btrfs_root *root,
6318                      u64 bytenr, u64 num_bytes, int reserved)
6319 {
6320         struct btrfs_block_group_cache *cache;
6321
6322         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6323         BUG_ON(!cache); /* Logic error */
6324
6325         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
6326
6327         btrfs_put_block_group(cache);
6328         return 0;
6329 }
6330
6331 /*
6332  * this function must be called within transaction
6333  */
6334 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
6335                                     u64 bytenr, u64 num_bytes)
6336 {
6337         struct btrfs_block_group_cache *cache;
6338         int ret;
6339
6340         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6341         if (!cache)
6342                 return -EINVAL;
6343
6344         /*
6345          * pull in the free space cache (if any) so that our pin
6346          * removes the free space from the cache.  We have load_only set
6347          * to one because the slow code to read in the free extents does check
6348          * the pinned extents.
6349          */
6350         cache_block_group(cache, 1);
6351
6352         pin_down_extent(root, cache, bytenr, num_bytes, 0);
6353
6354         /* remove us from the free space cache (if we're there at all) */
6355         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6356         btrfs_put_block_group(cache);
6357         return ret;
6358 }
6359
6360 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
6361 {
6362         int ret;
6363         struct btrfs_block_group_cache *block_group;
6364         struct btrfs_caching_control *caching_ctl;
6365
6366         block_group = btrfs_lookup_block_group(root->fs_info, start);
6367         if (!block_group)
6368                 return -EINVAL;
6369
6370         cache_block_group(block_group, 0);
6371         caching_ctl = get_caching_control(block_group);
6372
6373         if (!caching_ctl) {
6374                 /* Logic error */
6375                 BUG_ON(!block_group_cache_done(block_group));
6376                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6377         } else {
6378                 mutex_lock(&caching_ctl->mutex);
6379
6380                 if (start >= caching_ctl->progress) {
6381                         ret = add_excluded_extent(root, start, num_bytes);
6382                 } else if (start + num_bytes <= caching_ctl->progress) {
6383                         ret = btrfs_remove_free_space(block_group,
6384                                                       start, num_bytes);
6385                 } else {
6386                         num_bytes = caching_ctl->progress - start;
6387                         ret = btrfs_remove_free_space(block_group,
6388                                                       start, num_bytes);
6389                         if (ret)
6390                                 goto out_lock;
6391
6392                         num_bytes = (start + num_bytes) -
6393                                 caching_ctl->progress;
6394                         start = caching_ctl->progress;
6395                         ret = add_excluded_extent(root, start, num_bytes);
6396                 }
6397 out_lock:
6398                 mutex_unlock(&caching_ctl->mutex);
6399                 put_caching_control(caching_ctl);
6400         }
6401         btrfs_put_block_group(block_group);
6402         return ret;
6403 }
6404
6405 int btrfs_exclude_logged_extents(struct btrfs_root *log,
6406                                  struct extent_buffer *eb)
6407 {
6408         struct btrfs_file_extent_item *item;
6409         struct btrfs_key key;
6410         int found_type;
6411         int i;
6412
6413         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
6414                 return 0;
6415
6416         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6417                 btrfs_item_key_to_cpu(eb, &key, i);
6418                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6419                         continue;
6420                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6421                 found_type = btrfs_file_extent_type(eb, item);
6422                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6423                         continue;
6424                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6425                         continue;
6426                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6427                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6428                 __exclude_logged_extent(log, key.objectid, key.offset);
6429         }
6430
6431         return 0;
6432 }
6433
6434 static void
6435 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6436 {
6437         atomic_inc(&bg->reservations);
6438 }
6439
6440 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6441                                         const u64 start)
6442 {
6443         struct btrfs_block_group_cache *bg;
6444
6445         bg = btrfs_lookup_block_group(fs_info, start);
6446         ASSERT(bg);
6447         if (atomic_dec_and_test(&bg->reservations))
6448                 wake_up_atomic_t(&bg->reservations);
6449         btrfs_put_block_group(bg);
6450 }
6451
6452 static int btrfs_wait_bg_reservations_atomic_t(atomic_t *a)
6453 {
6454         schedule();
6455         return 0;
6456 }
6457
6458 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6459 {
6460         struct btrfs_space_info *space_info = bg->space_info;
6461
6462         ASSERT(bg->ro);
6463
6464         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6465                 return;
6466
6467         /*
6468          * Our block group is read only but before we set it to read only,
6469          * some task might have had allocated an extent from it already, but it
6470          * has not yet created a respective ordered extent (and added it to a
6471          * root's list of ordered extents).
6472          * Therefore wait for any task currently allocating extents, since the
6473          * block group's reservations counter is incremented while a read lock
6474          * on the groups' semaphore is held and decremented after releasing
6475          * the read access on that semaphore and creating the ordered extent.
6476          */
6477         down_write(&space_info->groups_sem);
6478         up_write(&space_info->groups_sem);
6479
6480         wait_on_atomic_t(&bg->reservations,
6481                          btrfs_wait_bg_reservations_atomic_t,
6482                          TASK_UNINTERRUPTIBLE);
6483 }
6484
6485 /**
6486  * btrfs_add_reserved_bytes - update the block_group and space info counters
6487  * @cache:      The cache we are manipulating
6488  * @ram_bytes:  The number of bytes of file content, and will be same to
6489  *              @num_bytes except for the compress path.
6490  * @num_bytes:  The number of bytes in question
6491  * @delalloc:   The blocks are allocated for the delalloc write
6492  *
6493  * This is called by the allocator when it reserves space. Metadata
6494  * reservations should be called with RESERVE_ALLOC so we do the proper
6495  * ENOSPC accounting.  For data we handle the reservation through clearing the
6496  * delalloc bits in the io_tree.  We have to do this since we could end up
6497  * allocating less disk space for the amount of data we have reserved in the
6498  * case of compression.
6499  *
6500  * If this is a reservation and the block group has become read only we cannot
6501  * make the reservation and return -EAGAIN, otherwise this function always
6502  * succeeds.
6503  */
6504 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6505                                     u64 ram_bytes, u64 num_bytes, int delalloc)
6506 {
6507         struct btrfs_space_info *space_info = cache->space_info;
6508         int ret = 0;
6509
6510         spin_lock(&space_info->lock);
6511         spin_lock(&cache->lock);
6512         if (cache->ro) {
6513                 ret = -EAGAIN;
6514         } else {
6515                 cache->reserved += num_bytes;
6516                 space_info->bytes_reserved += num_bytes;
6517
6518                 trace_btrfs_space_reservation(cache->fs_info,
6519                                 "space_info", space_info->flags,
6520                                 ram_bytes, 0);
6521                 space_info->bytes_may_use -= ram_bytes;
6522                 if (delalloc)
6523                         cache->delalloc_bytes += num_bytes;
6524         }
6525         spin_unlock(&cache->lock);
6526         spin_unlock(&space_info->lock);
6527         return ret;
6528 }
6529
6530 /**
6531  * btrfs_free_reserved_bytes - update the block_group and space info counters
6532  * @cache:      The cache we are manipulating
6533  * @num_bytes:  The number of bytes in question
6534  * @delalloc:   The blocks are allocated for the delalloc write
6535  *
6536  * This is called by somebody who is freeing space that was never actually used
6537  * on disk.  For example if you reserve some space for a new leaf in transaction
6538  * A and before transaction A commits you free that leaf, you call this with
6539  * reserve set to 0 in order to clear the reservation.
6540  */
6541
6542 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6543                                      u64 num_bytes, int delalloc)
6544 {
6545         struct btrfs_space_info *space_info = cache->space_info;
6546         int ret = 0;
6547
6548         spin_lock(&space_info->lock);
6549         spin_lock(&cache->lock);
6550         if (cache->ro)
6551                 space_info->bytes_readonly += num_bytes;
6552         cache->reserved -= num_bytes;
6553         space_info->bytes_reserved -= num_bytes;
6554
6555         if (delalloc)
6556                 cache->delalloc_bytes -= num_bytes;
6557         spin_unlock(&cache->lock);
6558         spin_unlock(&space_info->lock);
6559         return ret;
6560 }
6561 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
6562                                 struct btrfs_root *root)
6563 {
6564         struct btrfs_fs_info *fs_info = root->fs_info;
6565         struct btrfs_caching_control *next;
6566         struct btrfs_caching_control *caching_ctl;
6567         struct btrfs_block_group_cache *cache;
6568
6569         down_write(&fs_info->commit_root_sem);
6570
6571         list_for_each_entry_safe(caching_ctl, next,
6572                                  &fs_info->caching_block_groups, list) {
6573                 cache = caching_ctl->block_group;
6574                 if (block_group_cache_done(cache)) {
6575                         cache->last_byte_to_unpin = (u64)-1;
6576                         list_del_init(&caching_ctl->list);
6577                         put_caching_control(caching_ctl);
6578                 } else {
6579                         cache->last_byte_to_unpin = caching_ctl->progress;
6580                 }
6581         }
6582
6583         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6584                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6585         else
6586                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6587
6588         up_write(&fs_info->commit_root_sem);
6589
6590         update_global_block_rsv(fs_info);
6591 }
6592
6593 /*
6594  * Returns the free cluster for the given space info and sets empty_cluster to
6595  * what it should be based on the mount options.
6596  */
6597 static struct btrfs_free_cluster *
6598 fetch_cluster_info(struct btrfs_root *root, struct btrfs_space_info *space_info,
6599                    u64 *empty_cluster)
6600 {
6601         struct btrfs_free_cluster *ret = NULL;
6602         bool ssd = btrfs_test_opt(root->fs_info, SSD);
6603
6604         *empty_cluster = 0;
6605         if (btrfs_mixed_space_info(space_info))
6606                 return ret;
6607
6608         if (ssd)
6609                 *empty_cluster = SZ_2M;
6610         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6611                 ret = &root->fs_info->meta_alloc_cluster;
6612                 if (!ssd)
6613                         *empty_cluster = SZ_64K;
6614         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) {
6615                 ret = &root->fs_info->data_alloc_cluster;
6616         }
6617
6618         return ret;
6619 }
6620
6621 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
6622                               const bool return_free_space)
6623 {
6624         struct btrfs_fs_info *fs_info = root->fs_info;
6625         struct btrfs_block_group_cache *cache = NULL;
6626         struct btrfs_space_info *space_info;
6627         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6628         struct btrfs_free_cluster *cluster = NULL;
6629         u64 len;
6630         u64 total_unpinned = 0;
6631         u64 empty_cluster = 0;
6632         bool readonly;
6633
6634         while (start <= end) {
6635                 readonly = false;
6636                 if (!cache ||
6637                     start >= cache->key.objectid + cache->key.offset) {
6638                         if (cache)
6639                                 btrfs_put_block_group(cache);
6640                         total_unpinned = 0;
6641                         cache = btrfs_lookup_block_group(fs_info, start);
6642                         BUG_ON(!cache); /* Logic error */
6643
6644                         cluster = fetch_cluster_info(root,
6645                                                      cache->space_info,
6646                                                      &empty_cluster);
6647                         empty_cluster <<= 1;
6648                 }
6649
6650                 len = cache->key.objectid + cache->key.offset - start;
6651                 len = min(len, end + 1 - start);
6652
6653                 if (start < cache->last_byte_to_unpin) {
6654                         len = min(len, cache->last_byte_to_unpin - start);
6655                         if (return_free_space)
6656                                 btrfs_add_free_space(cache, start, len);
6657                 }
6658
6659                 start += len;
6660                 total_unpinned += len;
6661                 space_info = cache->space_info;
6662
6663                 /*
6664                  * If this space cluster has been marked as fragmented and we've
6665                  * unpinned enough in this block group to potentially allow a
6666                  * cluster to be created inside of it go ahead and clear the
6667                  * fragmented check.
6668                  */
6669                 if (cluster && cluster->fragmented &&
6670                     total_unpinned > empty_cluster) {
6671                         spin_lock(&cluster->lock);
6672                         cluster->fragmented = 0;
6673                         spin_unlock(&cluster->lock);
6674                 }
6675
6676                 spin_lock(&space_info->lock);
6677                 spin_lock(&cache->lock);
6678                 cache->pinned -= len;
6679                 space_info->bytes_pinned -= len;
6680
6681                 trace_btrfs_space_reservation(fs_info, "pinned",
6682                                               space_info->flags, len, 0);
6683                 space_info->max_extent_size = 0;
6684                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6685                 if (cache->ro) {
6686                         space_info->bytes_readonly += len;
6687                         readonly = true;
6688                 }
6689                 spin_unlock(&cache->lock);
6690                 if (!readonly && return_free_space &&
6691                     global_rsv->space_info == space_info) {
6692                         u64 to_add = len;
6693                         WARN_ON(!return_free_space);
6694                         spin_lock(&global_rsv->lock);
6695                         if (!global_rsv->full) {
6696                                 to_add = min(len, global_rsv->size -
6697                                              global_rsv->reserved);
6698                                 global_rsv->reserved += to_add;
6699                                 space_info->bytes_may_use += to_add;
6700                                 if (global_rsv->reserved >= global_rsv->size)
6701                                         global_rsv->full = 1;
6702                                 trace_btrfs_space_reservation(fs_info,
6703                                                               "space_info",
6704                                                               space_info->flags,
6705                                                               to_add, 1);
6706                                 len -= to_add;
6707                         }
6708                         spin_unlock(&global_rsv->lock);
6709                         /* Add to any tickets we may have */
6710                         if (len)
6711                                 space_info_add_new_bytes(fs_info, space_info,
6712                                                          len);
6713                 }
6714                 spin_unlock(&space_info->lock);
6715         }
6716
6717         if (cache)
6718                 btrfs_put_block_group(cache);
6719         return 0;
6720 }
6721
6722 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6723                                struct btrfs_root *root)
6724 {
6725         struct btrfs_fs_info *fs_info = root->fs_info;
6726         struct btrfs_block_group_cache *block_group, *tmp;
6727         struct list_head *deleted_bgs;
6728         struct extent_io_tree *unpin;
6729         u64 start;
6730         u64 end;
6731         int ret;
6732
6733         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6734                 unpin = &fs_info->freed_extents[1];
6735         else
6736                 unpin = &fs_info->freed_extents[0];
6737
6738         while (!trans->aborted) {
6739                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6740                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6741                                             EXTENT_DIRTY, NULL);
6742                 if (ret) {
6743                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6744                         break;
6745                 }
6746
6747                 if (btrfs_test_opt(root->fs_info, DISCARD))
6748                         ret = btrfs_discard_extent(root, start,
6749                                                    end + 1 - start, NULL);
6750
6751                 clear_extent_dirty(unpin, start, end);
6752                 unpin_extent_range(root, start, end, true);
6753                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6754                 cond_resched();
6755         }
6756
6757         /*
6758          * Transaction is finished.  We don't need the lock anymore.  We
6759          * do need to clean up the block groups in case of a transaction
6760          * abort.
6761          */
6762         deleted_bgs = &trans->transaction->deleted_bgs;
6763         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6764                 u64 trimmed = 0;
6765
6766                 ret = -EROFS;
6767                 if (!trans->aborted)
6768                         ret = btrfs_discard_extent(root,
6769                                                    block_group->key.objectid,
6770                                                    block_group->key.offset,
6771                                                    &trimmed);
6772
6773                 list_del_init(&block_group->bg_list);
6774                 btrfs_put_block_group_trimming(block_group);
6775                 btrfs_put_block_group(block_group);
6776
6777                 if (ret) {
6778                         const char *errstr = btrfs_decode_error(ret);
6779                         btrfs_warn(fs_info,
6780                                    "Discard failed while removing blockgroup: errno=%d %s\n",
6781                                    ret, errstr);
6782                 }
6783         }
6784
6785         return 0;
6786 }
6787
6788 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6789                              u64 owner, u64 root_objectid)
6790 {
6791         struct btrfs_space_info *space_info;
6792         u64 flags;
6793
6794         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6795                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6796                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
6797                 else
6798                         flags = BTRFS_BLOCK_GROUP_METADATA;
6799         } else {
6800                 flags = BTRFS_BLOCK_GROUP_DATA;
6801         }
6802
6803         space_info = __find_space_info(fs_info, flags);
6804         BUG_ON(!space_info); /* Logic bug */
6805         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6806 }
6807
6808
6809 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6810                                 struct btrfs_root *root,
6811                                 struct btrfs_delayed_ref_node *node, u64 parent,
6812                                 u64 root_objectid, u64 owner_objectid,
6813                                 u64 owner_offset, int refs_to_drop,
6814                                 struct btrfs_delayed_extent_op *extent_op)
6815 {
6816         struct btrfs_key key;
6817         struct btrfs_path *path;
6818         struct btrfs_fs_info *info = root->fs_info;
6819         struct btrfs_root *extent_root = info->extent_root;
6820         struct extent_buffer *leaf;
6821         struct btrfs_extent_item *ei;
6822         struct btrfs_extent_inline_ref *iref;
6823         int ret;
6824         int is_data;
6825         int extent_slot = 0;
6826         int found_extent = 0;
6827         int num_to_del = 1;
6828         u32 item_size;
6829         u64 refs;
6830         u64 bytenr = node->bytenr;
6831         u64 num_bytes = node->num_bytes;
6832         int last_ref = 0;
6833         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6834                                                  SKINNY_METADATA);
6835
6836         path = btrfs_alloc_path();
6837         if (!path)
6838                 return -ENOMEM;
6839
6840         path->reada = READA_FORWARD;
6841         path->leave_spinning = 1;
6842
6843         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6844         BUG_ON(!is_data && refs_to_drop != 1);
6845
6846         if (is_data)
6847                 skinny_metadata = 0;
6848
6849         ret = lookup_extent_backref(trans, extent_root, path, &iref,
6850                                     bytenr, num_bytes, parent,
6851                                     root_objectid, owner_objectid,
6852                                     owner_offset);
6853         if (ret == 0) {
6854                 extent_slot = path->slots[0];
6855                 while (extent_slot >= 0) {
6856                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6857                                               extent_slot);
6858                         if (key.objectid != bytenr)
6859                                 break;
6860                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6861                             key.offset == num_bytes) {
6862                                 found_extent = 1;
6863                                 break;
6864                         }
6865                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6866                             key.offset == owner_objectid) {
6867                                 found_extent = 1;
6868                                 break;
6869                         }
6870                         if (path->slots[0] - extent_slot > 5)
6871                                 break;
6872                         extent_slot--;
6873                 }
6874 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6875                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6876                 if (found_extent && item_size < sizeof(*ei))
6877                         found_extent = 0;
6878 #endif
6879                 if (!found_extent) {
6880                         BUG_ON(iref);
6881                         ret = remove_extent_backref(trans, extent_root, path,
6882                                                     NULL, refs_to_drop,
6883                                                     is_data, &last_ref);
6884                         if (ret) {
6885                                 btrfs_abort_transaction(trans, ret);
6886                                 goto out;
6887                         }
6888                         btrfs_release_path(path);
6889                         path->leave_spinning = 1;
6890
6891                         key.objectid = bytenr;
6892                         key.type = BTRFS_EXTENT_ITEM_KEY;
6893                         key.offset = num_bytes;
6894
6895                         if (!is_data && skinny_metadata) {
6896                                 key.type = BTRFS_METADATA_ITEM_KEY;
6897                                 key.offset = owner_objectid;
6898                         }
6899
6900                         ret = btrfs_search_slot(trans, extent_root,
6901                                                 &key, path, -1, 1);
6902                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6903                                 /*
6904                                  * Couldn't find our skinny metadata item,
6905                                  * see if we have ye olde extent item.
6906                                  */
6907                                 path->slots[0]--;
6908                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6909                                                       path->slots[0]);
6910                                 if (key.objectid == bytenr &&
6911                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6912                                     key.offset == num_bytes)
6913                                         ret = 0;
6914                         }
6915
6916                         if (ret > 0 && skinny_metadata) {
6917                                 skinny_metadata = false;
6918                                 key.objectid = bytenr;
6919                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6920                                 key.offset = num_bytes;
6921                                 btrfs_release_path(path);
6922                                 ret = btrfs_search_slot(trans, extent_root,
6923                                                         &key, path, -1, 1);
6924                         }
6925
6926                         if (ret) {
6927                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6928                                         ret, bytenr);
6929                                 if (ret > 0)
6930                                         btrfs_print_leaf(extent_root,
6931                                                          path->nodes[0]);
6932                         }
6933                         if (ret < 0) {
6934                                 btrfs_abort_transaction(trans, ret);
6935                                 goto out;
6936                         }
6937                         extent_slot = path->slots[0];
6938                 }
6939         } else if (WARN_ON(ret == -ENOENT)) {
6940                 btrfs_print_leaf(extent_root, path->nodes[0]);
6941                 btrfs_err(info,
6942                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6943                         bytenr, parent, root_objectid, owner_objectid,
6944                         owner_offset);
6945                 btrfs_abort_transaction(trans, ret);
6946                 goto out;
6947         } else {
6948                 btrfs_abort_transaction(trans, ret);
6949                 goto out;
6950         }
6951
6952         leaf = path->nodes[0];
6953         item_size = btrfs_item_size_nr(leaf, extent_slot);
6954 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6955         if (item_size < sizeof(*ei)) {
6956                 BUG_ON(found_extent || extent_slot != path->slots[0]);
6957                 ret = convert_extent_item_v0(trans, extent_root, path,
6958                                              owner_objectid, 0);
6959                 if (ret < 0) {
6960                         btrfs_abort_transaction(trans, ret);
6961                         goto out;
6962                 }
6963
6964                 btrfs_release_path(path);
6965                 path->leave_spinning = 1;
6966
6967                 key.objectid = bytenr;
6968                 key.type = BTRFS_EXTENT_ITEM_KEY;
6969                 key.offset = num_bytes;
6970
6971                 ret = btrfs_search_slot(trans, extent_root, &key, path,
6972                                         -1, 1);
6973                 if (ret) {
6974                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6975                                 ret, bytenr);
6976                         btrfs_print_leaf(extent_root, path->nodes[0]);
6977                 }
6978                 if (ret < 0) {
6979                         btrfs_abort_transaction(trans, ret);
6980                         goto out;
6981                 }
6982
6983                 extent_slot = path->slots[0];
6984                 leaf = path->nodes[0];
6985                 item_size = btrfs_item_size_nr(leaf, extent_slot);
6986         }
6987 #endif
6988         BUG_ON(item_size < sizeof(*ei));
6989         ei = btrfs_item_ptr(leaf, extent_slot,
6990                             struct btrfs_extent_item);
6991         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6992             key.type == BTRFS_EXTENT_ITEM_KEY) {
6993                 struct btrfs_tree_block_info *bi;
6994                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6995                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6996                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6997         }
6998
6999         refs = btrfs_extent_refs(leaf, ei);
7000         if (refs < refs_to_drop) {
7001                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
7002                           "for bytenr %Lu", refs_to_drop, refs, bytenr);
7003                 ret = -EINVAL;
7004                 btrfs_abort_transaction(trans, ret);
7005                 goto out;
7006         }
7007         refs -= refs_to_drop;
7008
7009         if (refs > 0) {
7010                 if (extent_op)
7011                         __run_delayed_extent_op(extent_op, leaf, ei);
7012                 /*
7013                  * In the case of inline back ref, reference count will
7014                  * be updated by remove_extent_backref
7015                  */
7016                 if (iref) {
7017                         BUG_ON(!found_extent);
7018                 } else {
7019                         btrfs_set_extent_refs(leaf, ei, refs);
7020                         btrfs_mark_buffer_dirty(leaf);
7021                 }
7022                 if (found_extent) {
7023                         ret = remove_extent_backref(trans, extent_root, path,
7024                                                     iref, refs_to_drop,
7025                                                     is_data, &last_ref);
7026                         if (ret) {
7027                                 btrfs_abort_transaction(trans, ret);
7028                                 goto out;
7029                         }
7030                 }
7031                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
7032                                  root_objectid);
7033         } else {
7034                 if (found_extent) {
7035                         BUG_ON(is_data && refs_to_drop !=
7036                                extent_data_ref_count(path, iref));
7037                         if (iref) {
7038                                 BUG_ON(path->slots[0] != extent_slot);
7039                         } else {
7040                                 BUG_ON(path->slots[0] != extent_slot + 1);
7041                                 path->slots[0] = extent_slot;
7042                                 num_to_del = 2;
7043                         }
7044                 }
7045
7046                 last_ref = 1;
7047                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
7048                                       num_to_del);
7049                 if (ret) {
7050                         btrfs_abort_transaction(trans, ret);
7051                         goto out;
7052                 }
7053                 btrfs_release_path(path);
7054
7055                 if (is_data) {
7056                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
7057                         if (ret) {
7058                                 btrfs_abort_transaction(trans, ret);
7059                                 goto out;
7060                         }
7061                 }
7062
7063                 ret = add_to_free_space_tree(trans, root->fs_info, bytenr,
7064                                              num_bytes);
7065                 if (ret) {
7066                         btrfs_abort_transaction(trans, ret);
7067                         goto out;
7068                 }
7069
7070                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
7071                 if (ret) {
7072                         btrfs_abort_transaction(trans, ret);
7073                         goto out;
7074                 }
7075         }
7076         btrfs_release_path(path);
7077
7078 out:
7079         btrfs_free_path(path);
7080         return ret;
7081 }
7082
7083 /*
7084  * when we free an block, it is possible (and likely) that we free the last
7085  * delayed ref for that extent as well.  This searches the delayed ref tree for
7086  * a given extent, and if there are no other delayed refs to be processed, it
7087  * removes it from the tree.
7088  */
7089 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
7090                                       struct btrfs_root *root, u64 bytenr)
7091 {
7092         struct btrfs_delayed_ref_head *head;
7093         struct btrfs_delayed_ref_root *delayed_refs;
7094         int ret = 0;
7095
7096         delayed_refs = &trans->transaction->delayed_refs;
7097         spin_lock(&delayed_refs->lock);
7098         head = btrfs_find_delayed_ref_head(trans, bytenr);
7099         if (!head)
7100                 goto out_delayed_unlock;
7101
7102         spin_lock(&head->lock);
7103         if (!list_empty(&head->ref_list))
7104                 goto out;
7105
7106         if (head->extent_op) {
7107                 if (!head->must_insert_reserved)
7108                         goto out;
7109                 btrfs_free_delayed_extent_op(head->extent_op);
7110                 head->extent_op = NULL;
7111         }
7112
7113         /*
7114          * waiting for the lock here would deadlock.  If someone else has it
7115          * locked they are already in the process of dropping it anyway
7116          */
7117         if (!mutex_trylock(&head->mutex))
7118                 goto out;
7119
7120         /*
7121          * at this point we have a head with no other entries.  Go
7122          * ahead and process it.
7123          */
7124         head->node.in_tree = 0;
7125         rb_erase(&head->href_node, &delayed_refs->href_root);
7126
7127         atomic_dec(&delayed_refs->num_entries);
7128
7129         /*
7130          * we don't take a ref on the node because we're removing it from the
7131          * tree, so we just steal the ref the tree was holding.
7132          */
7133         delayed_refs->num_heads--;
7134         if (head->processing == 0)
7135                 delayed_refs->num_heads_ready--;
7136         head->processing = 0;
7137         spin_unlock(&head->lock);
7138         spin_unlock(&delayed_refs->lock);
7139
7140         BUG_ON(head->extent_op);
7141         if (head->must_insert_reserved)
7142                 ret = 1;
7143
7144         mutex_unlock(&head->mutex);
7145         btrfs_put_delayed_ref(&head->node);
7146         return ret;
7147 out:
7148         spin_unlock(&head->lock);
7149
7150 out_delayed_unlock:
7151         spin_unlock(&delayed_refs->lock);
7152         return 0;
7153 }
7154
7155 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7156                            struct btrfs_root *root,
7157                            struct extent_buffer *buf,
7158                            u64 parent, int last_ref)
7159 {
7160         int pin = 1;
7161         int ret;
7162
7163         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7164                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7165                                         buf->start, buf->len,
7166                                         parent, root->root_key.objectid,
7167                                         btrfs_header_level(buf),
7168                                         BTRFS_DROP_DELAYED_REF, NULL);
7169                 BUG_ON(ret); /* -ENOMEM */
7170         }
7171
7172         if (!last_ref)
7173                 return;
7174
7175         if (btrfs_header_generation(buf) == trans->transid) {
7176                 struct btrfs_block_group_cache *cache;
7177
7178                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7179                         ret = check_ref_cleanup(trans, root, buf->start);
7180                         if (!ret)
7181                                 goto out;
7182                 }
7183
7184                 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
7185
7186                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7187                         pin_down_extent(root, cache, buf->start, buf->len, 1);
7188                         btrfs_put_block_group(cache);
7189                         goto out;
7190                 }
7191
7192                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7193
7194                 btrfs_add_free_space(cache, buf->start, buf->len);
7195                 btrfs_free_reserved_bytes(cache, buf->len, 0);
7196                 btrfs_put_block_group(cache);
7197                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
7198                 pin = 0;
7199         }
7200 out:
7201         if (pin)
7202                 add_pinned_bytes(root->fs_info, buf->len,
7203                                  btrfs_header_level(buf),
7204                                  root->root_key.objectid);
7205
7206         /*
7207          * Deleting the buffer, clear the corrupt flag since it doesn't matter
7208          * anymore.
7209          */
7210         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7211 }
7212
7213 /* Can return -ENOMEM */
7214 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7215                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7216                       u64 owner, u64 offset)
7217 {
7218         int ret;
7219         struct btrfs_fs_info *fs_info = root->fs_info;
7220
7221         if (btrfs_is_testing(fs_info))
7222                 return 0;
7223
7224         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
7225
7226         /*
7227          * tree log blocks never actually go into the extent allocation
7228          * tree, just update pinning info and exit early.
7229          */
7230         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7231                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7232                 /* unlocks the pinned mutex */
7233                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
7234                 ret = 0;
7235         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7236                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
7237                                         num_bytes,
7238                                         parent, root_objectid, (int)owner,
7239                                         BTRFS_DROP_DELAYED_REF, NULL);
7240         } else {
7241                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
7242                                                 num_bytes,
7243                                                 parent, root_objectid, owner,
7244                                                 offset, 0,
7245                                                 BTRFS_DROP_DELAYED_REF, NULL);
7246         }
7247         return ret;
7248 }
7249
7250 /*
7251  * when we wait for progress in the block group caching, its because
7252  * our allocation attempt failed at least once.  So, we must sleep
7253  * and let some progress happen before we try again.
7254  *
7255  * This function will sleep at least once waiting for new free space to
7256  * show up, and then it will check the block group free space numbers
7257  * for our min num_bytes.  Another option is to have it go ahead
7258  * and look in the rbtree for a free extent of a given size, but this
7259  * is a good start.
7260  *
7261  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7262  * any of the information in this block group.
7263  */
7264 static noinline void
7265 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7266                                 u64 num_bytes)
7267 {
7268         struct btrfs_caching_control *caching_ctl;
7269
7270         caching_ctl = get_caching_control(cache);
7271         if (!caching_ctl)
7272                 return;
7273
7274         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7275                    (cache->free_space_ctl->free_space >= num_bytes));
7276
7277         put_caching_control(caching_ctl);
7278 }
7279
7280 static noinline int
7281 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7282 {
7283         struct btrfs_caching_control *caching_ctl;
7284         int ret = 0;
7285
7286         caching_ctl = get_caching_control(cache);
7287         if (!caching_ctl)
7288                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7289
7290         wait_event(caching_ctl->wait, block_group_cache_done(cache));
7291         if (cache->cached == BTRFS_CACHE_ERROR)
7292                 ret = -EIO;
7293         put_caching_control(caching_ctl);
7294         return ret;
7295 }
7296
7297 int __get_raid_index(u64 flags)
7298 {
7299         if (flags & BTRFS_BLOCK_GROUP_RAID10)
7300                 return BTRFS_RAID_RAID10;
7301         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
7302                 return BTRFS_RAID_RAID1;
7303         else if (flags & BTRFS_BLOCK_GROUP_DUP)
7304                 return BTRFS_RAID_DUP;
7305         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
7306                 return BTRFS_RAID_RAID0;
7307         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
7308                 return BTRFS_RAID_RAID5;
7309         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
7310                 return BTRFS_RAID_RAID6;
7311
7312         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
7313 }
7314
7315 int get_block_group_index(struct btrfs_block_group_cache *cache)
7316 {
7317         return __get_raid_index(cache->flags);
7318 }
7319
7320 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
7321         [BTRFS_RAID_RAID10]     = "raid10",
7322         [BTRFS_RAID_RAID1]      = "raid1",
7323         [BTRFS_RAID_DUP]        = "dup",
7324         [BTRFS_RAID_RAID0]      = "raid0",
7325         [BTRFS_RAID_SINGLE]     = "single",
7326         [BTRFS_RAID_RAID5]      = "raid5",
7327         [BTRFS_RAID_RAID6]      = "raid6",
7328 };
7329
7330 static const char *get_raid_name(enum btrfs_raid_types type)
7331 {
7332         if (type >= BTRFS_NR_RAID_TYPES)
7333                 return NULL;
7334
7335         return btrfs_raid_type_names[type];
7336 }
7337
7338 enum btrfs_loop_type {
7339         LOOP_CACHING_NOWAIT = 0,
7340         LOOP_CACHING_WAIT = 1,
7341         LOOP_ALLOC_CHUNK = 2,
7342         LOOP_NO_EMPTY_SIZE = 3,
7343 };
7344
7345 static inline void
7346 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7347                        int delalloc)
7348 {
7349         if (delalloc)
7350                 down_read(&cache->data_rwsem);
7351 }
7352
7353 static inline void
7354 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7355                        int delalloc)
7356 {
7357         btrfs_get_block_group(cache);
7358         if (delalloc)
7359                 down_read(&cache->data_rwsem);
7360 }
7361
7362 static struct btrfs_block_group_cache *
7363 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7364                    struct btrfs_free_cluster *cluster,
7365                    int delalloc)
7366 {
7367         struct btrfs_block_group_cache *used_bg = NULL;
7368
7369         spin_lock(&cluster->refill_lock);
7370         while (1) {
7371                 used_bg = cluster->block_group;
7372                 if (!used_bg)
7373                         return NULL;
7374
7375                 if (used_bg == block_group)
7376                         return used_bg;
7377
7378                 btrfs_get_block_group(used_bg);
7379
7380                 if (!delalloc)
7381                         return used_bg;
7382
7383                 if (down_read_trylock(&used_bg->data_rwsem))
7384                         return used_bg;
7385
7386                 spin_unlock(&cluster->refill_lock);
7387
7388                 down_read(&used_bg->data_rwsem);
7389
7390                 spin_lock(&cluster->refill_lock);
7391                 if (used_bg == cluster->block_group)
7392                         return used_bg;
7393
7394                 up_read(&used_bg->data_rwsem);
7395                 btrfs_put_block_group(used_bg);
7396         }
7397 }
7398
7399 static inline void
7400 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7401                          int delalloc)
7402 {
7403         if (delalloc)
7404                 up_read(&cache->data_rwsem);
7405         btrfs_put_block_group(cache);
7406 }
7407
7408 /*
7409  * walks the btree of allocated extents and find a hole of a given size.
7410  * The key ins is changed to record the hole:
7411  * ins->objectid == start position
7412  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7413  * ins->offset == the size of the hole.
7414  * Any available blocks before search_start are skipped.
7415  *
7416  * If there is no suitable free space, we will record the max size of
7417  * the free space extent currently.
7418  */
7419 static noinline int find_free_extent(struct btrfs_root *orig_root,
7420                                 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7421                                 u64 hint_byte, struct btrfs_key *ins,
7422                                 u64 flags, int delalloc)
7423 {
7424         int ret = 0;
7425         struct btrfs_root *root = orig_root->fs_info->extent_root;
7426         struct btrfs_free_cluster *last_ptr = NULL;
7427         struct btrfs_block_group_cache *block_group = NULL;
7428         u64 search_start = 0;
7429         u64 max_extent_size = 0;
7430         u64 empty_cluster = 0;
7431         struct btrfs_space_info *space_info;
7432         int loop = 0;
7433         int index = __get_raid_index(flags);
7434         bool failed_cluster_refill = false;
7435         bool failed_alloc = false;
7436         bool use_cluster = true;
7437         bool have_caching_bg = false;
7438         bool orig_have_caching_bg = false;
7439         bool full_search = false;
7440
7441         WARN_ON(num_bytes < root->sectorsize);
7442         ins->type = BTRFS_EXTENT_ITEM_KEY;
7443         ins->objectid = 0;
7444         ins->offset = 0;
7445
7446         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
7447
7448         space_info = __find_space_info(root->fs_info, flags);
7449         if (!space_info) {
7450                 btrfs_err(root->fs_info, "No space info for %llu", flags);
7451                 return -ENOSPC;
7452         }
7453
7454         /*
7455          * If our free space is heavily fragmented we may not be able to make
7456          * big contiguous allocations, so instead of doing the expensive search
7457          * for free space, simply return ENOSPC with our max_extent_size so we
7458          * can go ahead and search for a more manageable chunk.
7459          *
7460          * If our max_extent_size is large enough for our allocation simply
7461          * disable clustering since we will likely not be able to find enough
7462          * space to create a cluster and induce latency trying.
7463          */
7464         if (unlikely(space_info->max_extent_size)) {
7465                 spin_lock(&space_info->lock);
7466                 if (space_info->max_extent_size &&
7467                     num_bytes > space_info->max_extent_size) {
7468                         ins->offset = space_info->max_extent_size;
7469                         spin_unlock(&space_info->lock);
7470                         return -ENOSPC;
7471                 } else if (space_info->max_extent_size) {
7472                         use_cluster = false;
7473                 }
7474                 spin_unlock(&space_info->lock);
7475         }
7476
7477         last_ptr = fetch_cluster_info(orig_root, space_info, &empty_cluster);
7478         if (last_ptr) {
7479                 spin_lock(&last_ptr->lock);
7480                 if (last_ptr->block_group)
7481                         hint_byte = last_ptr->window_start;
7482                 if (last_ptr->fragmented) {
7483                         /*
7484                          * We still set window_start so we can keep track of the
7485                          * last place we found an allocation to try and save
7486                          * some time.
7487                          */
7488                         hint_byte = last_ptr->window_start;
7489                         use_cluster = false;
7490                 }
7491                 spin_unlock(&last_ptr->lock);
7492         }
7493
7494         search_start = max(search_start, first_logical_byte(root, 0));
7495         search_start = max(search_start, hint_byte);
7496         if (search_start == hint_byte) {
7497                 block_group = btrfs_lookup_block_group(root->fs_info,
7498                                                        search_start);
7499                 /*
7500                  * we don't want to use the block group if it doesn't match our
7501                  * allocation bits, or if its not cached.
7502                  *
7503                  * However if we are re-searching with an ideal block group
7504                  * picked out then we don't care that the block group is cached.
7505                  */
7506                 if (block_group && block_group_bits(block_group, flags) &&
7507                     block_group->cached != BTRFS_CACHE_NO) {
7508                         down_read(&space_info->groups_sem);
7509                         if (list_empty(&block_group->list) ||
7510                             block_group->ro) {
7511                                 /*
7512                                  * someone is removing this block group,
7513                                  * we can't jump into the have_block_group
7514                                  * target because our list pointers are not
7515                                  * valid
7516                                  */
7517                                 btrfs_put_block_group(block_group);
7518                                 up_read(&space_info->groups_sem);
7519                         } else {
7520                                 index = get_block_group_index(block_group);
7521                                 btrfs_lock_block_group(block_group, delalloc);
7522                                 goto have_block_group;
7523                         }
7524                 } else if (block_group) {
7525                         btrfs_put_block_group(block_group);
7526                 }
7527         }
7528 search:
7529         have_caching_bg = false;
7530         if (index == 0 || index == __get_raid_index(flags))
7531                 full_search = true;
7532         down_read(&space_info->groups_sem);
7533         list_for_each_entry(block_group, &space_info->block_groups[index],
7534                             list) {
7535                 u64 offset;
7536                 int cached;
7537
7538                 btrfs_grab_block_group(block_group, delalloc);
7539                 search_start = block_group->key.objectid;
7540
7541                 /*
7542                  * this can happen if we end up cycling through all the
7543                  * raid types, but we want to make sure we only allocate
7544                  * for the proper type.
7545                  */
7546                 if (!block_group_bits(block_group, flags)) {
7547                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
7548                                 BTRFS_BLOCK_GROUP_RAID1 |
7549                                 BTRFS_BLOCK_GROUP_RAID5 |
7550                                 BTRFS_BLOCK_GROUP_RAID6 |
7551                                 BTRFS_BLOCK_GROUP_RAID10;
7552
7553                         /*
7554                          * if they asked for extra copies and this block group
7555                          * doesn't provide them, bail.  This does allow us to
7556                          * fill raid0 from raid1.
7557                          */
7558                         if ((flags & extra) && !(block_group->flags & extra))
7559                                 goto loop;
7560                 }
7561
7562 have_block_group:
7563                 cached = block_group_cache_done(block_group);
7564                 if (unlikely(!cached)) {
7565                         have_caching_bg = true;
7566                         ret = cache_block_group(block_group, 0);
7567                         BUG_ON(ret < 0);
7568                         ret = 0;
7569                 }
7570
7571                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7572                         goto loop;
7573                 if (unlikely(block_group->ro))
7574                         goto loop;
7575
7576                 /*
7577                  * Ok we want to try and use the cluster allocator, so
7578                  * lets look there
7579                  */
7580                 if (last_ptr && use_cluster) {
7581                         struct btrfs_block_group_cache *used_block_group;
7582                         unsigned long aligned_cluster;
7583                         /*
7584                          * the refill lock keeps out other
7585                          * people trying to start a new cluster
7586                          */
7587                         used_block_group = btrfs_lock_cluster(block_group,
7588                                                               last_ptr,
7589                                                               delalloc);
7590                         if (!used_block_group)
7591                                 goto refill_cluster;
7592
7593                         if (used_block_group != block_group &&
7594                             (used_block_group->ro ||
7595                              !block_group_bits(used_block_group, flags)))
7596                                 goto release_cluster;
7597
7598                         offset = btrfs_alloc_from_cluster(used_block_group,
7599                                                 last_ptr,
7600                                                 num_bytes,
7601                                                 used_block_group->key.objectid,
7602                                                 &max_extent_size);
7603                         if (offset) {
7604                                 /* we have a block, we're done */
7605                                 spin_unlock(&last_ptr->refill_lock);
7606                                 trace_btrfs_reserve_extent_cluster(root,
7607                                                 used_block_group,
7608                                                 search_start, num_bytes);
7609                                 if (used_block_group != block_group) {
7610                                         btrfs_release_block_group(block_group,
7611                                                                   delalloc);
7612                                         block_group = used_block_group;
7613                                 }
7614                                 goto checks;
7615                         }
7616
7617                         WARN_ON(last_ptr->block_group != used_block_group);
7618 release_cluster:
7619                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7620                          * set up a new clusters, so lets just skip it
7621                          * and let the allocator find whatever block
7622                          * it can find.  If we reach this point, we
7623                          * will have tried the cluster allocator
7624                          * plenty of times and not have found
7625                          * anything, so we are likely way too
7626                          * fragmented for the clustering stuff to find
7627                          * anything.
7628                          *
7629                          * However, if the cluster is taken from the
7630                          * current block group, release the cluster
7631                          * first, so that we stand a better chance of
7632                          * succeeding in the unclustered
7633                          * allocation.  */
7634                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7635                             used_block_group != block_group) {
7636                                 spin_unlock(&last_ptr->refill_lock);
7637                                 btrfs_release_block_group(used_block_group,
7638                                                           delalloc);
7639                                 goto unclustered_alloc;
7640                         }
7641
7642                         /*
7643                          * this cluster didn't work out, free it and
7644                          * start over
7645                          */
7646                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7647
7648                         if (used_block_group != block_group)
7649                                 btrfs_release_block_group(used_block_group,
7650                                                           delalloc);
7651 refill_cluster:
7652                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7653                                 spin_unlock(&last_ptr->refill_lock);
7654                                 goto unclustered_alloc;
7655                         }
7656
7657                         aligned_cluster = max_t(unsigned long,
7658                                                 empty_cluster + empty_size,
7659                                               block_group->full_stripe_len);
7660
7661                         /* allocate a cluster in this block group */
7662                         ret = btrfs_find_space_cluster(root, block_group,
7663                                                        last_ptr, search_start,
7664                                                        num_bytes,
7665                                                        aligned_cluster);
7666                         if (ret == 0) {
7667                                 /*
7668                                  * now pull our allocation out of this
7669                                  * cluster
7670                                  */
7671                                 offset = btrfs_alloc_from_cluster(block_group,
7672                                                         last_ptr,
7673                                                         num_bytes,
7674                                                         search_start,
7675                                                         &max_extent_size);
7676                                 if (offset) {
7677                                         /* we found one, proceed */
7678                                         spin_unlock(&last_ptr->refill_lock);
7679                                         trace_btrfs_reserve_extent_cluster(root,
7680                                                 block_group, search_start,
7681                                                 num_bytes);
7682                                         goto checks;
7683                                 }
7684                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7685                                    && !failed_cluster_refill) {
7686                                 spin_unlock(&last_ptr->refill_lock);
7687
7688                                 failed_cluster_refill = true;
7689                                 wait_block_group_cache_progress(block_group,
7690                                        num_bytes + empty_cluster + empty_size);
7691                                 goto have_block_group;
7692                         }
7693
7694                         /*
7695                          * at this point we either didn't find a cluster
7696                          * or we weren't able to allocate a block from our
7697                          * cluster.  Free the cluster we've been trying
7698                          * to use, and go to the next block group
7699                          */
7700                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7701                         spin_unlock(&last_ptr->refill_lock);
7702                         goto loop;
7703                 }
7704
7705 unclustered_alloc:
7706                 /*
7707                  * We are doing an unclustered alloc, set the fragmented flag so
7708                  * we don't bother trying to setup a cluster again until we get
7709                  * more space.
7710                  */
7711                 if (unlikely(last_ptr)) {
7712                         spin_lock(&last_ptr->lock);
7713                         last_ptr->fragmented = 1;
7714                         spin_unlock(&last_ptr->lock);
7715                 }
7716                 spin_lock(&block_group->free_space_ctl->tree_lock);
7717                 if (cached &&
7718                     block_group->free_space_ctl->free_space <
7719                     num_bytes + empty_cluster + empty_size) {
7720                         if (block_group->free_space_ctl->free_space >
7721                             max_extent_size)
7722                                 max_extent_size =
7723                                         block_group->free_space_ctl->free_space;
7724                         spin_unlock(&block_group->free_space_ctl->tree_lock);
7725                         goto loop;
7726                 }
7727                 spin_unlock(&block_group->free_space_ctl->tree_lock);
7728
7729                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7730                                                     num_bytes, empty_size,
7731                                                     &max_extent_size);
7732                 /*
7733                  * If we didn't find a chunk, and we haven't failed on this
7734                  * block group before, and this block group is in the middle of
7735                  * caching and we are ok with waiting, then go ahead and wait
7736                  * for progress to be made, and set failed_alloc to true.
7737                  *
7738                  * If failed_alloc is true then we've already waited on this
7739                  * block group once and should move on to the next block group.
7740                  */
7741                 if (!offset && !failed_alloc && !cached &&
7742                     loop > LOOP_CACHING_NOWAIT) {
7743                         wait_block_group_cache_progress(block_group,
7744                                                 num_bytes + empty_size);
7745                         failed_alloc = true;
7746                         goto have_block_group;
7747                 } else if (!offset) {
7748                         goto loop;
7749                 }
7750 checks:
7751                 search_start = ALIGN(offset, root->stripesize);
7752
7753                 /* move on to the next group */
7754                 if (search_start + num_bytes >
7755                     block_group->key.objectid + block_group->key.offset) {
7756                         btrfs_add_free_space(block_group, offset, num_bytes);
7757                         goto loop;
7758                 }
7759
7760                 if (offset < search_start)
7761                         btrfs_add_free_space(block_group, offset,
7762                                              search_start - offset);
7763                 BUG_ON(offset > search_start);
7764
7765                 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7766                                 num_bytes, delalloc);
7767                 if (ret == -EAGAIN) {
7768                         btrfs_add_free_space(block_group, offset, num_bytes);
7769                         goto loop;
7770                 }
7771                 btrfs_inc_block_group_reservations(block_group);
7772
7773                 /* we are all good, lets return */
7774                 ins->objectid = search_start;
7775                 ins->offset = num_bytes;
7776
7777                 trace_btrfs_reserve_extent(orig_root, block_group,
7778                                            search_start, num_bytes);
7779                 btrfs_release_block_group(block_group, delalloc);
7780                 break;
7781 loop:
7782                 failed_cluster_refill = false;
7783                 failed_alloc = false;
7784                 BUG_ON(index != get_block_group_index(block_group));
7785                 btrfs_release_block_group(block_group, delalloc);
7786         }
7787         up_read(&space_info->groups_sem);
7788
7789         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7790                 && !orig_have_caching_bg)
7791                 orig_have_caching_bg = true;
7792
7793         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7794                 goto search;
7795
7796         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7797                 goto search;
7798
7799         /*
7800          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7801          *                      caching kthreads as we move along
7802          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7803          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7804          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7805          *                      again
7806          */
7807         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7808                 index = 0;
7809                 if (loop == LOOP_CACHING_NOWAIT) {
7810                         /*
7811                          * We want to skip the LOOP_CACHING_WAIT step if we
7812                          * don't have any uncached bgs and we've already done a
7813                          * full search through.
7814                          */
7815                         if (orig_have_caching_bg || !full_search)
7816                                 loop = LOOP_CACHING_WAIT;
7817                         else
7818                                 loop = LOOP_ALLOC_CHUNK;
7819                 } else {
7820                         loop++;
7821                 }
7822
7823                 if (loop == LOOP_ALLOC_CHUNK) {
7824                         struct btrfs_trans_handle *trans;
7825                         int exist = 0;
7826
7827                         trans = current->journal_info;
7828                         if (trans)
7829                                 exist = 1;
7830                         else
7831                                 trans = btrfs_join_transaction(root);
7832
7833                         if (IS_ERR(trans)) {
7834                                 ret = PTR_ERR(trans);
7835                                 goto out;
7836                         }
7837
7838                         ret = do_chunk_alloc(trans, root, flags,
7839                                              CHUNK_ALLOC_FORCE);
7840
7841                         /*
7842                          * If we can't allocate a new chunk we've already looped
7843                          * through at least once, move on to the NO_EMPTY_SIZE
7844                          * case.
7845                          */
7846                         if (ret == -ENOSPC)
7847                                 loop = LOOP_NO_EMPTY_SIZE;
7848
7849                         /*
7850                          * Do not bail out on ENOSPC since we
7851                          * can do more things.
7852                          */
7853                         if (ret < 0 && ret != -ENOSPC)
7854                                 btrfs_abort_transaction(trans, ret);
7855                         else
7856                                 ret = 0;
7857                         if (!exist)
7858                                 btrfs_end_transaction(trans, root);
7859                         if (ret)
7860                                 goto out;
7861                 }
7862
7863                 if (loop == LOOP_NO_EMPTY_SIZE) {
7864                         /*
7865                          * Don't loop again if we already have no empty_size and
7866                          * no empty_cluster.
7867                          */
7868                         if (empty_size == 0 &&
7869                             empty_cluster == 0) {
7870                                 ret = -ENOSPC;
7871                                 goto out;
7872                         }
7873                         empty_size = 0;
7874                         empty_cluster = 0;
7875                 }
7876
7877                 goto search;
7878         } else if (!ins->objectid) {
7879                 ret = -ENOSPC;
7880         } else if (ins->objectid) {
7881                 if (!use_cluster && last_ptr) {
7882                         spin_lock(&last_ptr->lock);
7883                         last_ptr->window_start = ins->objectid;
7884                         spin_unlock(&last_ptr->lock);
7885                 }
7886                 ret = 0;
7887         }
7888 out:
7889         if (ret == -ENOSPC) {
7890                 spin_lock(&space_info->lock);
7891                 space_info->max_extent_size = max_extent_size;
7892                 spin_unlock(&space_info->lock);
7893                 ins->offset = max_extent_size;
7894         }
7895         return ret;
7896 }
7897
7898 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
7899                             int dump_block_groups)
7900 {
7901         struct btrfs_block_group_cache *cache;
7902         int index = 0;
7903
7904         spin_lock(&info->lock);
7905         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
7906                info->flags,
7907                info->total_bytes - info->bytes_used - info->bytes_pinned -
7908                info->bytes_reserved - info->bytes_readonly -
7909                info->bytes_may_use, (info->full) ? "" : "not ");
7910         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
7911                "reserved=%llu, may_use=%llu, readonly=%llu\n",
7912                info->total_bytes, info->bytes_used, info->bytes_pinned,
7913                info->bytes_reserved, info->bytes_may_use,
7914                info->bytes_readonly);
7915         spin_unlock(&info->lock);
7916
7917         if (!dump_block_groups)
7918                 return;
7919
7920         down_read(&info->groups_sem);
7921 again:
7922         list_for_each_entry(cache, &info->block_groups[index], list) {
7923                 spin_lock(&cache->lock);
7924                 printk(KERN_INFO "BTRFS: "
7925                            "block group %llu has %llu bytes, "
7926                            "%llu used %llu pinned %llu reserved %s\n",
7927                        cache->key.objectid, cache->key.offset,
7928                        btrfs_block_group_used(&cache->item), cache->pinned,
7929                        cache->reserved, cache->ro ? "[readonly]" : "");
7930                 btrfs_dump_free_space(cache, bytes);
7931                 spin_unlock(&cache->lock);
7932         }
7933         if (++index < BTRFS_NR_RAID_TYPES)
7934                 goto again;
7935         up_read(&info->groups_sem);
7936 }
7937
7938 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
7939                          u64 num_bytes, u64 min_alloc_size,
7940                          u64 empty_size, u64 hint_byte,
7941                          struct btrfs_key *ins, int is_data, int delalloc)
7942 {
7943         bool final_tried = num_bytes == min_alloc_size;
7944         u64 flags;
7945         int ret;
7946
7947         flags = btrfs_get_alloc_profile(root, is_data);
7948 again:
7949         WARN_ON(num_bytes < root->sectorsize);
7950         ret = find_free_extent(root, ram_bytes, num_bytes, empty_size,
7951                                hint_byte, ins, flags, delalloc);
7952         if (!ret && !is_data) {
7953                 btrfs_dec_block_group_reservations(root->fs_info,
7954                                                    ins->objectid);
7955         } else if (ret == -ENOSPC) {
7956                 if (!final_tried && ins->offset) {
7957                         num_bytes = min(num_bytes >> 1, ins->offset);
7958                         num_bytes = round_down(num_bytes, root->sectorsize);
7959                         num_bytes = max(num_bytes, min_alloc_size);
7960                         ram_bytes = num_bytes;
7961                         if (num_bytes == min_alloc_size)
7962                                 final_tried = true;
7963                         goto again;
7964                 } else if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
7965                         struct btrfs_space_info *sinfo;
7966
7967                         sinfo = __find_space_info(root->fs_info, flags);
7968                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
7969                                 flags, num_bytes);
7970                         if (sinfo)
7971                                 dump_space_info(sinfo, num_bytes, 1);
7972                 }
7973         }
7974
7975         return ret;
7976 }
7977
7978 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7979                                         u64 start, u64 len,
7980                                         int pin, int delalloc)
7981 {
7982         struct btrfs_block_group_cache *cache;
7983         int ret = 0;
7984
7985         cache = btrfs_lookup_block_group(root->fs_info, start);
7986         if (!cache) {
7987                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7988                         start);
7989                 return -ENOSPC;
7990         }
7991
7992         if (pin)
7993                 pin_down_extent(root, cache, start, len, 1);
7994         else {
7995                 if (btrfs_test_opt(root->fs_info, DISCARD))
7996                         ret = btrfs_discard_extent(root, start, len, NULL);
7997                 btrfs_add_free_space(cache, start, len);
7998                 btrfs_free_reserved_bytes(cache, len, delalloc);
7999                 trace_btrfs_reserved_extent_free(root, start, len);
8000         }
8001
8002         btrfs_put_block_group(cache);
8003         return ret;
8004 }
8005
8006 int btrfs_free_reserved_extent(struct btrfs_root *root,
8007                                u64 start, u64 len, int delalloc)
8008 {
8009         return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
8010 }
8011
8012 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
8013                                        u64 start, u64 len)
8014 {
8015         return __btrfs_free_reserved_extent(root, start, len, 1, 0);
8016 }
8017
8018 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8019                                       struct btrfs_root *root,
8020                                       u64 parent, u64 root_objectid,
8021                                       u64 flags, u64 owner, u64 offset,
8022                                       struct btrfs_key *ins, int ref_mod)
8023 {
8024         int ret;
8025         struct btrfs_fs_info *fs_info = root->fs_info;
8026         struct btrfs_extent_item *extent_item;
8027         struct btrfs_extent_inline_ref *iref;
8028         struct btrfs_path *path;
8029         struct extent_buffer *leaf;
8030         int type;
8031         u32 size;
8032
8033         if (parent > 0)
8034                 type = BTRFS_SHARED_DATA_REF_KEY;
8035         else
8036                 type = BTRFS_EXTENT_DATA_REF_KEY;
8037
8038         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8039
8040         path = btrfs_alloc_path();
8041         if (!path)
8042                 return -ENOMEM;
8043
8044         path->leave_spinning = 1;
8045         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8046                                       ins, size);
8047         if (ret) {
8048                 btrfs_free_path(path);
8049                 return ret;
8050         }
8051
8052         leaf = path->nodes[0];
8053         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8054                                      struct btrfs_extent_item);
8055         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8056         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8057         btrfs_set_extent_flags(leaf, extent_item,
8058                                flags | BTRFS_EXTENT_FLAG_DATA);
8059
8060         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8061         btrfs_set_extent_inline_ref_type(leaf, iref, type);
8062         if (parent > 0) {
8063                 struct btrfs_shared_data_ref *ref;
8064                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8065                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8066                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8067         } else {
8068                 struct btrfs_extent_data_ref *ref;
8069                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8070                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8071                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8072                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8073                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8074         }
8075
8076         btrfs_mark_buffer_dirty(path->nodes[0]);
8077         btrfs_free_path(path);
8078
8079         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8080                                           ins->offset);
8081         if (ret)
8082                 return ret;
8083
8084         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
8085         if (ret) { /* -ENOENT, logic error */
8086                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8087                         ins->objectid, ins->offset);
8088                 BUG();
8089         }
8090         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
8091         return ret;
8092 }
8093
8094 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8095                                      struct btrfs_root *root,
8096                                      u64 parent, u64 root_objectid,
8097                                      u64 flags, struct btrfs_disk_key *key,
8098                                      int level, struct btrfs_key *ins)
8099 {
8100         int ret;
8101         struct btrfs_fs_info *fs_info = root->fs_info;
8102         struct btrfs_extent_item *extent_item;
8103         struct btrfs_tree_block_info *block_info;
8104         struct btrfs_extent_inline_ref *iref;
8105         struct btrfs_path *path;
8106         struct extent_buffer *leaf;
8107         u32 size = sizeof(*extent_item) + sizeof(*iref);
8108         u64 num_bytes = ins->offset;
8109         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8110                                                  SKINNY_METADATA);
8111
8112         if (!skinny_metadata)
8113                 size += sizeof(*block_info);
8114
8115         path = btrfs_alloc_path();
8116         if (!path) {
8117                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8118                                                    root->nodesize);
8119                 return -ENOMEM;
8120         }
8121
8122         path->leave_spinning = 1;
8123         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8124                                       ins, size);
8125         if (ret) {
8126                 btrfs_free_path(path);
8127                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
8128                                                    root->nodesize);
8129                 return ret;
8130         }
8131
8132         leaf = path->nodes[0];
8133         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8134                                      struct btrfs_extent_item);
8135         btrfs_set_extent_refs(leaf, extent_item, 1);
8136         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8137         btrfs_set_extent_flags(leaf, extent_item,
8138                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8139
8140         if (skinny_metadata) {
8141                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8142                 num_bytes = root->nodesize;
8143         } else {
8144                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8145                 btrfs_set_tree_block_key(leaf, block_info, key);
8146                 btrfs_set_tree_block_level(leaf, block_info, level);
8147                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8148         }
8149
8150         if (parent > 0) {
8151                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8152                 btrfs_set_extent_inline_ref_type(leaf, iref,
8153                                                  BTRFS_SHARED_BLOCK_REF_KEY);
8154                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8155         } else {
8156                 btrfs_set_extent_inline_ref_type(leaf, iref,
8157                                                  BTRFS_TREE_BLOCK_REF_KEY);
8158                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
8159         }
8160
8161         btrfs_mark_buffer_dirty(leaf);
8162         btrfs_free_path(path);
8163
8164         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8165                                           num_bytes);
8166         if (ret)
8167                 return ret;
8168
8169         ret = update_block_group(trans, root, ins->objectid, root->nodesize,
8170                                  1);
8171         if (ret) { /* -ENOENT, logic error */
8172                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8173                         ins->objectid, ins->offset);
8174                 BUG();
8175         }
8176
8177         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
8178         return ret;
8179 }
8180
8181 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8182                                      struct btrfs_root *root,
8183                                      u64 root_objectid, u64 owner,
8184                                      u64 offset, u64 ram_bytes,
8185                                      struct btrfs_key *ins)
8186 {
8187         int ret;
8188
8189         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
8190
8191         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
8192                                          ins->offset, 0,
8193                                          root_objectid, owner, offset,
8194                                          ram_bytes, BTRFS_ADD_DELAYED_EXTENT,
8195                                          NULL);
8196         return ret;
8197 }
8198
8199 /*
8200  * this is used by the tree logging recovery code.  It records that
8201  * an extent has been allocated and makes sure to clear the free
8202  * space cache bits as well
8203  */
8204 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8205                                    struct btrfs_root *root,
8206                                    u64 root_objectid, u64 owner, u64 offset,
8207                                    struct btrfs_key *ins)
8208 {
8209         int ret;
8210         struct btrfs_block_group_cache *block_group;
8211         struct btrfs_space_info *space_info;
8212
8213         /*
8214          * Mixed block groups will exclude before processing the log so we only
8215          * need to do the exclude dance if this fs isn't mixed.
8216          */
8217         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
8218                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
8219                 if (ret)
8220                         return ret;
8221         }
8222
8223         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
8224         if (!block_group)
8225                 return -EINVAL;
8226
8227         space_info = block_group->space_info;
8228         spin_lock(&space_info->lock);
8229         spin_lock(&block_group->lock);
8230         space_info->bytes_reserved += ins->offset;
8231         block_group->reserved += ins->offset;
8232         spin_unlock(&block_group->lock);
8233         spin_unlock(&space_info->lock);
8234
8235         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
8236                                          0, owner, offset, ins, 1);
8237         btrfs_put_block_group(block_group);
8238         return ret;
8239 }
8240
8241 static struct extent_buffer *
8242 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8243                       u64 bytenr, int level)
8244 {
8245         struct extent_buffer *buf;
8246
8247         buf = btrfs_find_create_tree_block(root, bytenr);
8248         if (IS_ERR(buf))
8249                 return buf;
8250
8251         btrfs_set_header_generation(buf, trans->transid);
8252         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8253         btrfs_tree_lock(buf);
8254         clean_tree_block(trans, root->fs_info, buf);
8255         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8256
8257         btrfs_set_lock_blocking(buf);
8258         set_extent_buffer_uptodate(buf);
8259
8260         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8261                 buf->log_index = root->log_transid % 2;
8262                 /*
8263                  * we allow two log transactions at a time, use different
8264                  * EXENT bit to differentiate dirty pages.
8265                  */
8266                 if (buf->log_index == 0)
8267                         set_extent_dirty(&root->dirty_log_pages, buf->start,
8268                                         buf->start + buf->len - 1, GFP_NOFS);
8269                 else
8270                         set_extent_new(&root->dirty_log_pages, buf->start,
8271                                         buf->start + buf->len - 1);
8272         } else {
8273                 buf->log_index = -1;
8274                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8275                          buf->start + buf->len - 1, GFP_NOFS);
8276         }
8277         trans->dirty = true;
8278         /* this returns a buffer locked for blocking */
8279         return buf;
8280 }
8281
8282 static struct btrfs_block_rsv *
8283 use_block_rsv(struct btrfs_trans_handle *trans,
8284               struct btrfs_root *root, u32 blocksize)
8285 {
8286         struct btrfs_block_rsv *block_rsv;
8287         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
8288         int ret;
8289         bool global_updated = false;
8290
8291         block_rsv = get_block_rsv(trans, root);
8292
8293         if (unlikely(block_rsv->size == 0))
8294                 goto try_reserve;
8295 again:
8296         ret = block_rsv_use_bytes(block_rsv, blocksize);
8297         if (!ret)
8298                 return block_rsv;
8299
8300         if (block_rsv->failfast)
8301                 return ERR_PTR(ret);
8302
8303         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8304                 global_updated = true;
8305                 update_global_block_rsv(root->fs_info);
8306                 goto again;
8307         }
8308
8309         if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
8310                 static DEFINE_RATELIMIT_STATE(_rs,
8311                                 DEFAULT_RATELIMIT_INTERVAL * 10,
8312                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
8313                 if (__ratelimit(&_rs))
8314                         WARN(1, KERN_DEBUG
8315                                 "BTRFS: block rsv returned %d\n", ret);
8316         }
8317 try_reserve:
8318         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8319                                      BTRFS_RESERVE_NO_FLUSH);
8320         if (!ret)
8321                 return block_rsv;
8322         /*
8323          * If we couldn't reserve metadata bytes try and use some from
8324          * the global reserve if its space type is the same as the global
8325          * reservation.
8326          */
8327         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8328             block_rsv->space_info == global_rsv->space_info) {
8329                 ret = block_rsv_use_bytes(global_rsv, blocksize);
8330                 if (!ret)
8331                         return global_rsv;
8332         }
8333         return ERR_PTR(ret);
8334 }
8335
8336 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8337                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
8338 {
8339         block_rsv_add_bytes(block_rsv, blocksize, 0);
8340         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
8341 }
8342
8343 /*
8344  * finds a free extent and does all the dirty work required for allocation
8345  * returns the tree buffer or an ERR_PTR on error.
8346  */
8347 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8348                                         struct btrfs_root *root,
8349                                         u64 parent, u64 root_objectid,
8350                                         struct btrfs_disk_key *key, int level,
8351                                         u64 hint, u64 empty_size)
8352 {
8353         struct btrfs_key ins;
8354         struct btrfs_block_rsv *block_rsv;
8355         struct extent_buffer *buf;
8356         struct btrfs_delayed_extent_op *extent_op;
8357         u64 flags = 0;
8358         int ret;
8359         u32 blocksize = root->nodesize;
8360         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8361                                                  SKINNY_METADATA);
8362
8363 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8364         if (btrfs_is_testing(root->fs_info)) {
8365                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8366                                             level);
8367                 if (!IS_ERR(buf))
8368                         root->alloc_bytenr += blocksize;
8369                 return buf;
8370         }
8371 #endif
8372
8373         block_rsv = use_block_rsv(trans, root, blocksize);
8374         if (IS_ERR(block_rsv))
8375                 return ERR_CAST(block_rsv);
8376
8377         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8378                                    empty_size, hint, &ins, 0, 0);
8379         if (ret)
8380                 goto out_unuse;
8381
8382         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8383         if (IS_ERR(buf)) {
8384                 ret = PTR_ERR(buf);
8385                 goto out_free_reserved;
8386         }
8387
8388         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8389                 if (parent == 0)
8390                         parent = ins.objectid;
8391                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8392         } else
8393                 BUG_ON(parent > 0);
8394
8395         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8396                 extent_op = btrfs_alloc_delayed_extent_op();
8397                 if (!extent_op) {
8398                         ret = -ENOMEM;
8399                         goto out_free_buf;
8400                 }
8401                 if (key)
8402                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8403                 else
8404                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8405                 extent_op->flags_to_set = flags;
8406                 extent_op->update_key = skinny_metadata ? false : true;
8407                 extent_op->update_flags = true;
8408                 extent_op->is_data = false;
8409                 extent_op->level = level;
8410
8411                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
8412                                                  ins.objectid, ins.offset,
8413                                                  parent, root_objectid, level,
8414                                                  BTRFS_ADD_DELAYED_EXTENT,
8415                                                  extent_op);
8416                 if (ret)
8417                         goto out_free_delayed;
8418         }
8419         return buf;
8420
8421 out_free_delayed:
8422         btrfs_free_delayed_extent_op(extent_op);
8423 out_free_buf:
8424         free_extent_buffer(buf);
8425 out_free_reserved:
8426         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
8427 out_unuse:
8428         unuse_block_rsv(root->fs_info, block_rsv, blocksize);
8429         return ERR_PTR(ret);
8430 }
8431
8432 struct walk_control {
8433         u64 refs[BTRFS_MAX_LEVEL];
8434         u64 flags[BTRFS_MAX_LEVEL];
8435         struct btrfs_key update_progress;
8436         int stage;
8437         int level;
8438         int shared_level;
8439         int update_ref;
8440         int keep_locks;
8441         int reada_slot;
8442         int reada_count;
8443         int for_reloc;
8444 };
8445
8446 #define DROP_REFERENCE  1
8447 #define UPDATE_BACKREF  2
8448
8449 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8450                                      struct btrfs_root *root,
8451                                      struct walk_control *wc,
8452                                      struct btrfs_path *path)
8453 {
8454         u64 bytenr;
8455         u64 generation;
8456         u64 refs;
8457         u64 flags;
8458         u32 nritems;
8459         struct btrfs_key key;
8460         struct extent_buffer *eb;
8461         int ret;
8462         int slot;
8463         int nread = 0;
8464
8465         if (path->slots[wc->level] < wc->reada_slot) {
8466                 wc->reada_count = wc->reada_count * 2 / 3;
8467                 wc->reada_count = max(wc->reada_count, 2);
8468         } else {
8469                 wc->reada_count = wc->reada_count * 3 / 2;
8470                 wc->reada_count = min_t(int, wc->reada_count,
8471                                         BTRFS_NODEPTRS_PER_BLOCK(root));
8472         }
8473
8474         eb = path->nodes[wc->level];
8475         nritems = btrfs_header_nritems(eb);
8476
8477         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8478                 if (nread >= wc->reada_count)
8479                         break;
8480
8481                 cond_resched();
8482                 bytenr = btrfs_node_blockptr(eb, slot);
8483                 generation = btrfs_node_ptr_generation(eb, slot);
8484
8485                 if (slot == path->slots[wc->level])
8486                         goto reada;
8487
8488                 if (wc->stage == UPDATE_BACKREF &&
8489                     generation <= root->root_key.offset)
8490                         continue;
8491
8492                 /* We don't lock the tree block, it's OK to be racy here */
8493                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
8494                                                wc->level - 1, 1, &refs,
8495                                                &flags);
8496                 /* We don't care about errors in readahead. */
8497                 if (ret < 0)
8498                         continue;
8499                 BUG_ON(refs == 0);
8500
8501                 if (wc->stage == DROP_REFERENCE) {
8502                         if (refs == 1)
8503                                 goto reada;
8504
8505                         if (wc->level == 1 &&
8506                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8507                                 continue;
8508                         if (!wc->update_ref ||
8509                             generation <= root->root_key.offset)
8510                                 continue;
8511                         btrfs_node_key_to_cpu(eb, &key, slot);
8512                         ret = btrfs_comp_cpu_keys(&key,
8513                                                   &wc->update_progress);
8514                         if (ret < 0)
8515                                 continue;
8516                 } else {
8517                         if (wc->level == 1 &&
8518                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8519                                 continue;
8520                 }
8521 reada:
8522                 readahead_tree_block(root, bytenr);
8523                 nread++;
8524         }
8525         wc->reada_slot = slot;
8526 }
8527
8528 static int account_leaf_items(struct btrfs_trans_handle *trans,
8529                               struct btrfs_root *root,
8530                               struct extent_buffer *eb)
8531 {
8532         int nr = btrfs_header_nritems(eb);
8533         int i, extent_type, ret;
8534         struct btrfs_key key;
8535         struct btrfs_file_extent_item *fi;
8536         u64 bytenr, num_bytes;
8537
8538         /* We can be called directly from walk_up_proc() */
8539         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags))
8540                 return 0;
8541
8542         for (i = 0; i < nr; i++) {
8543                 btrfs_item_key_to_cpu(eb, &key, i);
8544
8545                 if (key.type != BTRFS_EXTENT_DATA_KEY)
8546                         continue;
8547
8548                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
8549                 /* filter out non qgroup-accountable extents  */
8550                 extent_type = btrfs_file_extent_type(eb, fi);
8551
8552                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
8553                         continue;
8554
8555                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
8556                 if (!bytenr)
8557                         continue;
8558
8559                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
8560
8561                 ret = btrfs_qgroup_insert_dirty_extent(trans, root->fs_info,
8562                                 bytenr, num_bytes, GFP_NOFS);
8563                 if (ret)
8564                         return ret;
8565         }
8566         return 0;
8567 }
8568
8569 /*
8570  * Walk up the tree from the bottom, freeing leaves and any interior
8571  * nodes which have had all slots visited. If a node (leaf or
8572  * interior) is freed, the node above it will have it's slot
8573  * incremented. The root node will never be freed.
8574  *
8575  * At the end of this function, we should have a path which has all
8576  * slots incremented to the next position for a search. If we need to
8577  * read a new node it will be NULL and the node above it will have the
8578  * correct slot selected for a later read.
8579  *
8580  * If we increment the root nodes slot counter past the number of
8581  * elements, 1 is returned to signal completion of the search.
8582  */
8583 static int adjust_slots_upwards(struct btrfs_root *root,
8584                                 struct btrfs_path *path, int root_level)
8585 {
8586         int level = 0;
8587         int nr, slot;
8588         struct extent_buffer *eb;
8589
8590         if (root_level == 0)
8591                 return 1;
8592
8593         while (level <= root_level) {
8594                 eb = path->nodes[level];
8595                 nr = btrfs_header_nritems(eb);
8596                 path->slots[level]++;
8597                 slot = path->slots[level];
8598                 if (slot >= nr || level == 0) {
8599                         /*
8600                          * Don't free the root -  we will detect this
8601                          * condition after our loop and return a
8602                          * positive value for caller to stop walking the tree.
8603                          */
8604                         if (level != root_level) {
8605                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8606                                 path->locks[level] = 0;
8607
8608                                 free_extent_buffer(eb);
8609                                 path->nodes[level] = NULL;
8610                                 path->slots[level] = 0;
8611                         }
8612                 } else {
8613                         /*
8614                          * We have a valid slot to walk back down
8615                          * from. Stop here so caller can process these
8616                          * new nodes.
8617                          */
8618                         break;
8619                 }
8620
8621                 level++;
8622         }
8623
8624         eb = path->nodes[root_level];
8625         if (path->slots[root_level] >= btrfs_header_nritems(eb))
8626                 return 1;
8627
8628         return 0;
8629 }
8630
8631 /*
8632  * root_eb is the subtree root and is locked before this function is called.
8633  */
8634 static int account_shared_subtree(struct btrfs_trans_handle *trans,
8635                                   struct btrfs_root *root,
8636                                   struct extent_buffer *root_eb,
8637                                   u64 root_gen,
8638                                   int root_level)
8639 {
8640         int ret = 0;
8641         int level;
8642         struct extent_buffer *eb = root_eb;
8643         struct btrfs_path *path = NULL;
8644
8645         BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
8646         BUG_ON(root_eb == NULL);
8647
8648         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags))
8649                 return 0;
8650
8651         if (!extent_buffer_uptodate(root_eb)) {
8652                 ret = btrfs_read_buffer(root_eb, root_gen);
8653                 if (ret)
8654                         goto out;
8655         }
8656
8657         if (root_level == 0) {
8658                 ret = account_leaf_items(trans, root, root_eb);
8659                 goto out;
8660         }
8661
8662         path = btrfs_alloc_path();
8663         if (!path)
8664                 return -ENOMEM;
8665
8666         /*
8667          * Walk down the tree.  Missing extent blocks are filled in as
8668          * we go. Metadata is accounted every time we read a new
8669          * extent block.
8670          *
8671          * When we reach a leaf, we account for file extent items in it,
8672          * walk back up the tree (adjusting slot pointers as we go)
8673          * and restart the search process.
8674          */
8675         extent_buffer_get(root_eb); /* For path */
8676         path->nodes[root_level] = root_eb;
8677         path->slots[root_level] = 0;
8678         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
8679 walk_down:
8680         level = root_level;
8681         while (level >= 0) {
8682                 if (path->nodes[level] == NULL) {
8683                         int parent_slot;
8684                         u64 child_gen;
8685                         u64 child_bytenr;
8686
8687                         /* We need to get child blockptr/gen from
8688                          * parent before we can read it. */
8689                         eb = path->nodes[level + 1];
8690                         parent_slot = path->slots[level + 1];
8691                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
8692                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
8693
8694                         eb = read_tree_block(root, child_bytenr, child_gen);
8695                         if (IS_ERR(eb)) {
8696                                 ret = PTR_ERR(eb);
8697                                 goto out;
8698                         } else if (!extent_buffer_uptodate(eb)) {
8699                                 free_extent_buffer(eb);
8700                                 ret = -EIO;
8701                                 goto out;
8702                         }
8703
8704                         path->nodes[level] = eb;
8705                         path->slots[level] = 0;
8706
8707                         btrfs_tree_read_lock(eb);
8708                         btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
8709                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
8710
8711                         ret = btrfs_qgroup_insert_dirty_extent(trans,
8712                                         root->fs_info, child_bytenr,
8713                                         root->nodesize, GFP_NOFS);
8714                         if (ret)
8715                                 goto out;
8716                 }
8717
8718                 if (level == 0) {
8719                         ret = account_leaf_items(trans, root, path->nodes[level]);
8720                         if (ret)
8721                                 goto out;
8722
8723                         /* Nonzero return here means we completed our search */
8724                         ret = adjust_slots_upwards(root, path, root_level);
8725                         if (ret)
8726                                 break;
8727
8728                         /* Restart search with new slots */
8729                         goto walk_down;
8730                 }
8731
8732                 level--;
8733         }
8734
8735         ret = 0;
8736 out:
8737         btrfs_free_path(path);
8738
8739         return ret;
8740 }
8741
8742 /*
8743  * helper to process tree block while walking down the tree.
8744  *
8745  * when wc->stage == UPDATE_BACKREF, this function updates
8746  * back refs for pointers in the block.
8747  *
8748  * NOTE: return value 1 means we should stop walking down.
8749  */
8750 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8751                                    struct btrfs_root *root,
8752                                    struct btrfs_path *path,
8753                                    struct walk_control *wc, int lookup_info)
8754 {
8755         int level = wc->level;
8756         struct extent_buffer *eb = path->nodes[level];
8757         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8758         int ret;
8759
8760         if (wc->stage == UPDATE_BACKREF &&
8761             btrfs_header_owner(eb) != root->root_key.objectid)
8762                 return 1;
8763
8764         /*
8765          * when reference count of tree block is 1, it won't increase
8766          * again. once full backref flag is set, we never clear it.
8767          */
8768         if (lookup_info &&
8769             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8770              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8771                 BUG_ON(!path->locks[level]);
8772                 ret = btrfs_lookup_extent_info(trans, root,
8773                                                eb->start, level, 1,
8774                                                &wc->refs[level],
8775                                                &wc->flags[level]);
8776                 BUG_ON(ret == -ENOMEM);
8777                 if (ret)
8778                         return ret;
8779                 BUG_ON(wc->refs[level] == 0);
8780         }
8781
8782         if (wc->stage == DROP_REFERENCE) {
8783                 if (wc->refs[level] > 1)
8784                         return 1;
8785
8786                 if (path->locks[level] && !wc->keep_locks) {
8787                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8788                         path->locks[level] = 0;
8789                 }
8790                 return 0;
8791         }
8792
8793         /* wc->stage == UPDATE_BACKREF */
8794         if (!(wc->flags[level] & flag)) {
8795                 BUG_ON(!path->locks[level]);
8796                 ret = btrfs_inc_ref(trans, root, eb, 1);
8797                 BUG_ON(ret); /* -ENOMEM */
8798                 ret = btrfs_dec_ref(trans, root, eb, 0);
8799                 BUG_ON(ret); /* -ENOMEM */
8800                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
8801                                                   eb->len, flag,
8802                                                   btrfs_header_level(eb), 0);
8803                 BUG_ON(ret); /* -ENOMEM */
8804                 wc->flags[level] |= flag;
8805         }
8806
8807         /*
8808          * the block is shared by multiple trees, so it's not good to
8809          * keep the tree lock
8810          */
8811         if (path->locks[level] && level > 0) {
8812                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8813                 path->locks[level] = 0;
8814         }
8815         return 0;
8816 }
8817
8818 /*
8819  * helper to process tree block pointer.
8820  *
8821  * when wc->stage == DROP_REFERENCE, this function checks
8822  * reference count of the block pointed to. if the block
8823  * is shared and we need update back refs for the subtree
8824  * rooted at the block, this function changes wc->stage to
8825  * UPDATE_BACKREF. if the block is shared and there is no
8826  * need to update back, this function drops the reference
8827  * to the block.
8828  *
8829  * NOTE: return value 1 means we should stop walking down.
8830  */
8831 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8832                                  struct btrfs_root *root,
8833                                  struct btrfs_path *path,
8834                                  struct walk_control *wc, int *lookup_info)
8835 {
8836         u64 bytenr;
8837         u64 generation;
8838         u64 parent;
8839         u32 blocksize;
8840         struct btrfs_key key;
8841         struct extent_buffer *next;
8842         int level = wc->level;
8843         int reada = 0;
8844         int ret = 0;
8845         bool need_account = false;
8846
8847         generation = btrfs_node_ptr_generation(path->nodes[level],
8848                                                path->slots[level]);
8849         /*
8850          * if the lower level block was created before the snapshot
8851          * was created, we know there is no need to update back refs
8852          * for the subtree
8853          */
8854         if (wc->stage == UPDATE_BACKREF &&
8855             generation <= root->root_key.offset) {
8856                 *lookup_info = 1;
8857                 return 1;
8858         }
8859
8860         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8861         blocksize = root->nodesize;
8862
8863         next = btrfs_find_tree_block(root->fs_info, bytenr);
8864         if (!next) {
8865                 next = btrfs_find_create_tree_block(root, bytenr);
8866                 if (IS_ERR(next))
8867                         return PTR_ERR(next);
8868
8869                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8870                                                level - 1);
8871                 reada = 1;
8872         }
8873         btrfs_tree_lock(next);
8874         btrfs_set_lock_blocking(next);
8875
8876         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8877                                        &wc->refs[level - 1],
8878                                        &wc->flags[level - 1]);
8879         if (ret < 0) {
8880                 btrfs_tree_unlock(next);
8881                 return ret;
8882         }
8883
8884         if (unlikely(wc->refs[level - 1] == 0)) {
8885                 btrfs_err(root->fs_info, "Missing references.");
8886                 BUG();
8887         }
8888         *lookup_info = 0;
8889
8890         if (wc->stage == DROP_REFERENCE) {
8891                 if (wc->refs[level - 1] > 1) {
8892                         need_account = true;
8893                         if (level == 1 &&
8894                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8895                                 goto skip;
8896
8897                         if (!wc->update_ref ||
8898                             generation <= root->root_key.offset)
8899                                 goto skip;
8900
8901                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8902                                               path->slots[level]);
8903                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8904                         if (ret < 0)
8905                                 goto skip;
8906
8907                         wc->stage = UPDATE_BACKREF;
8908                         wc->shared_level = level - 1;
8909                 }
8910         } else {
8911                 if (level == 1 &&
8912                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8913                         goto skip;
8914         }
8915
8916         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8917                 btrfs_tree_unlock(next);
8918                 free_extent_buffer(next);
8919                 next = NULL;
8920                 *lookup_info = 1;
8921         }
8922
8923         if (!next) {
8924                 if (reada && level == 1)
8925                         reada_walk_down(trans, root, wc, path);
8926                 next = read_tree_block(root, bytenr, generation);
8927                 if (IS_ERR(next)) {
8928                         return PTR_ERR(next);
8929                 } else if (!extent_buffer_uptodate(next)) {
8930                         free_extent_buffer(next);
8931                         return -EIO;
8932                 }
8933                 btrfs_tree_lock(next);
8934                 btrfs_set_lock_blocking(next);
8935         }
8936
8937         level--;
8938         BUG_ON(level != btrfs_header_level(next));
8939         path->nodes[level] = next;
8940         path->slots[level] = 0;
8941         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8942         wc->level = level;
8943         if (wc->level == 1)
8944                 wc->reada_slot = 0;
8945         return 0;
8946 skip:
8947         wc->refs[level - 1] = 0;
8948         wc->flags[level - 1] = 0;
8949         if (wc->stage == DROP_REFERENCE) {
8950                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8951                         parent = path->nodes[level]->start;
8952                 } else {
8953                         BUG_ON(root->root_key.objectid !=
8954                                btrfs_header_owner(path->nodes[level]));
8955                         parent = 0;
8956                 }
8957
8958                 if (need_account) {
8959                         ret = account_shared_subtree(trans, root, next,
8960                                                      generation, level - 1);
8961                         if (ret) {
8962                                 btrfs_err_rl(root->fs_info,
8963                                         "Error "
8964                                         "%d accounting shared subtree. Quota "
8965                                         "is out of sync, rescan required.",
8966                                         ret);
8967                         }
8968                 }
8969                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8970                                 root->root_key.objectid, level - 1, 0);
8971                 BUG_ON(ret); /* -ENOMEM */
8972         }
8973         btrfs_tree_unlock(next);
8974         free_extent_buffer(next);
8975         *lookup_info = 1;
8976         return 1;
8977 }
8978
8979 /*
8980  * helper to process tree block while walking up the tree.
8981  *
8982  * when wc->stage == DROP_REFERENCE, this function drops
8983  * reference count on the block.
8984  *
8985  * when wc->stage == UPDATE_BACKREF, this function changes
8986  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8987  * to UPDATE_BACKREF previously while processing the block.
8988  *
8989  * NOTE: return value 1 means we should stop walking up.
8990  */
8991 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8992                                  struct btrfs_root *root,
8993                                  struct btrfs_path *path,
8994                                  struct walk_control *wc)
8995 {
8996         int ret;
8997         int level = wc->level;
8998         struct extent_buffer *eb = path->nodes[level];
8999         u64 parent = 0;
9000
9001         if (wc->stage == UPDATE_BACKREF) {
9002                 BUG_ON(wc->shared_level < level);
9003                 if (level < wc->shared_level)
9004                         goto out;
9005
9006                 ret = find_next_key(path, level + 1, &wc->update_progress);
9007                 if (ret > 0)
9008                         wc->update_ref = 0;
9009
9010                 wc->stage = DROP_REFERENCE;
9011                 wc->shared_level = -1;
9012                 path->slots[level] = 0;
9013
9014                 /*
9015                  * check reference count again if the block isn't locked.
9016                  * we should start walking down the tree again if reference
9017                  * count is one.
9018                  */
9019                 if (!path->locks[level]) {
9020                         BUG_ON(level == 0);
9021                         btrfs_tree_lock(eb);
9022                         btrfs_set_lock_blocking(eb);
9023                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9024
9025                         ret = btrfs_lookup_extent_info(trans, root,
9026                                                        eb->start, level, 1,
9027                                                        &wc->refs[level],
9028                                                        &wc->flags[level]);
9029                         if (ret < 0) {
9030                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
9031                                 path->locks[level] = 0;
9032                                 return ret;
9033                         }
9034                         BUG_ON(wc->refs[level] == 0);
9035                         if (wc->refs[level] == 1) {
9036                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
9037                                 path->locks[level] = 0;
9038                                 return 1;
9039                         }
9040                 }
9041         }
9042
9043         /* wc->stage == DROP_REFERENCE */
9044         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
9045
9046         if (wc->refs[level] == 1) {
9047                 if (level == 0) {
9048                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9049                                 ret = btrfs_dec_ref(trans, root, eb, 1);
9050                         else
9051                                 ret = btrfs_dec_ref(trans, root, eb, 0);
9052                         BUG_ON(ret); /* -ENOMEM */
9053                         ret = account_leaf_items(trans, root, eb);
9054                         if (ret) {
9055                                 btrfs_err_rl(root->fs_info,
9056                                         "error "
9057                                         "%d accounting leaf items. Quota "
9058                                         "is out of sync, rescan required.",
9059                                         ret);
9060                         }
9061                 }
9062                 /* make block locked assertion in clean_tree_block happy */
9063                 if (!path->locks[level] &&
9064                     btrfs_header_generation(eb) == trans->transid) {
9065                         btrfs_tree_lock(eb);
9066                         btrfs_set_lock_blocking(eb);
9067                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9068                 }
9069                 clean_tree_block(trans, root->fs_info, eb);
9070         }
9071
9072         if (eb == root->node) {
9073                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9074                         parent = eb->start;
9075                 else
9076                         BUG_ON(root->root_key.objectid !=
9077                                btrfs_header_owner(eb));
9078         } else {
9079                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9080                         parent = path->nodes[level + 1]->start;
9081                 else
9082                         BUG_ON(root->root_key.objectid !=
9083                                btrfs_header_owner(path->nodes[level + 1]));
9084         }
9085
9086         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
9087 out:
9088         wc->refs[level] = 0;
9089         wc->flags[level] = 0;
9090         return 0;
9091 }
9092
9093 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
9094                                    struct btrfs_root *root,
9095                                    struct btrfs_path *path,
9096                                    struct walk_control *wc)
9097 {
9098         int level = wc->level;
9099         int lookup_info = 1;
9100         int ret;
9101
9102         while (level >= 0) {
9103                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
9104                 if (ret > 0)
9105                         break;
9106
9107                 if (level == 0)
9108                         break;
9109
9110                 if (path->slots[level] >=
9111                     btrfs_header_nritems(path->nodes[level]))
9112                         break;
9113
9114                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
9115                 if (ret > 0) {
9116                         path->slots[level]++;
9117                         continue;
9118                 } else if (ret < 0)
9119                         return ret;
9120                 level = wc->level;
9121         }
9122         return 0;
9123 }
9124
9125 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
9126                                  struct btrfs_root *root,
9127                                  struct btrfs_path *path,
9128                                  struct walk_control *wc, int max_level)
9129 {
9130         int level = wc->level;
9131         int ret;
9132
9133         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
9134         while (level < max_level && path->nodes[level]) {
9135                 wc->level = level;
9136                 if (path->slots[level] + 1 <
9137                     btrfs_header_nritems(path->nodes[level])) {
9138                         path->slots[level]++;
9139                         return 0;
9140                 } else {
9141                         ret = walk_up_proc(trans, root, path, wc);
9142                         if (ret > 0)
9143                                 return 0;
9144
9145                         if (path->locks[level]) {
9146                                 btrfs_tree_unlock_rw(path->nodes[level],
9147                                                      path->locks[level]);
9148                                 path->locks[level] = 0;
9149                         }
9150                         free_extent_buffer(path->nodes[level]);
9151                         path->nodes[level] = NULL;
9152                         level++;
9153                 }
9154         }
9155         return 1;
9156 }
9157
9158 /*
9159  * drop a subvolume tree.
9160  *
9161  * this function traverses the tree freeing any blocks that only
9162  * referenced by the tree.
9163  *
9164  * when a shared tree block is found. this function decreases its
9165  * reference count by one. if update_ref is true, this function
9166  * also make sure backrefs for the shared block and all lower level
9167  * blocks are properly updated.
9168  *
9169  * If called with for_reloc == 0, may exit early with -EAGAIN
9170  */
9171 int btrfs_drop_snapshot(struct btrfs_root *root,
9172                          struct btrfs_block_rsv *block_rsv, int update_ref,
9173                          int for_reloc)
9174 {
9175         struct btrfs_path *path;
9176         struct btrfs_trans_handle *trans;
9177         struct btrfs_root *tree_root = root->fs_info->tree_root;
9178         struct btrfs_root_item *root_item = &root->root_item;
9179         struct walk_control *wc;
9180         struct btrfs_key key;
9181         int err = 0;
9182         int ret;
9183         int level;
9184         bool root_dropped = false;
9185
9186         btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
9187
9188         path = btrfs_alloc_path();
9189         if (!path) {
9190                 err = -ENOMEM;
9191                 goto out;
9192         }
9193
9194         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9195         if (!wc) {
9196                 btrfs_free_path(path);
9197                 err = -ENOMEM;
9198                 goto out;
9199         }
9200
9201         trans = btrfs_start_transaction(tree_root, 0);
9202         if (IS_ERR(trans)) {
9203                 err = PTR_ERR(trans);
9204                 goto out_free;
9205         }
9206
9207         if (block_rsv)
9208                 trans->block_rsv = block_rsv;
9209
9210         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9211                 level = btrfs_header_level(root->node);
9212                 path->nodes[level] = btrfs_lock_root_node(root);
9213                 btrfs_set_lock_blocking(path->nodes[level]);
9214                 path->slots[level] = 0;
9215                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9216                 memset(&wc->update_progress, 0,
9217                        sizeof(wc->update_progress));
9218         } else {
9219                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9220                 memcpy(&wc->update_progress, &key,
9221                        sizeof(wc->update_progress));
9222
9223                 level = root_item->drop_level;
9224                 BUG_ON(level == 0);
9225                 path->lowest_level = level;
9226                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9227                 path->lowest_level = 0;
9228                 if (ret < 0) {
9229                         err = ret;
9230                         goto out_end_trans;
9231                 }
9232                 WARN_ON(ret > 0);
9233
9234                 /*
9235                  * unlock our path, this is safe because only this
9236                  * function is allowed to delete this snapshot
9237                  */
9238                 btrfs_unlock_up_safe(path, 0);
9239
9240                 level = btrfs_header_level(root->node);
9241                 while (1) {
9242                         btrfs_tree_lock(path->nodes[level]);
9243                         btrfs_set_lock_blocking(path->nodes[level]);
9244                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9245
9246                         ret = btrfs_lookup_extent_info(trans, root,
9247                                                 path->nodes[level]->start,
9248                                                 level, 1, &wc->refs[level],
9249                                                 &wc->flags[level]);
9250                         if (ret < 0) {
9251                                 err = ret;
9252                                 goto out_end_trans;
9253                         }
9254                         BUG_ON(wc->refs[level] == 0);
9255
9256                         if (level == root_item->drop_level)
9257                                 break;
9258
9259                         btrfs_tree_unlock(path->nodes[level]);
9260                         path->locks[level] = 0;
9261                         WARN_ON(wc->refs[level] != 1);
9262                         level--;
9263                 }
9264         }
9265
9266         wc->level = level;
9267         wc->shared_level = -1;
9268         wc->stage = DROP_REFERENCE;
9269         wc->update_ref = update_ref;
9270         wc->keep_locks = 0;
9271         wc->for_reloc = for_reloc;
9272         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9273
9274         while (1) {
9275
9276                 ret = walk_down_tree(trans, root, path, wc);
9277                 if (ret < 0) {
9278                         err = ret;
9279                         break;
9280                 }
9281
9282                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9283                 if (ret < 0) {
9284                         err = ret;
9285                         break;
9286                 }
9287
9288                 if (ret > 0) {
9289                         BUG_ON(wc->stage != DROP_REFERENCE);
9290                         break;
9291                 }
9292
9293                 if (wc->stage == DROP_REFERENCE) {
9294                         level = wc->level;
9295                         btrfs_node_key(path->nodes[level],
9296                                        &root_item->drop_progress,
9297                                        path->slots[level]);
9298                         root_item->drop_level = level;
9299                 }
9300
9301                 BUG_ON(wc->level == 0);
9302                 if (btrfs_should_end_transaction(trans, tree_root) ||
9303                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
9304                         ret = btrfs_update_root(trans, tree_root,
9305                                                 &root->root_key,
9306                                                 root_item);
9307                         if (ret) {
9308                                 btrfs_abort_transaction(trans, ret);
9309                                 err = ret;
9310                                 goto out_end_trans;
9311                         }
9312
9313                         btrfs_end_transaction_throttle(trans, tree_root);
9314                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
9315                                 pr_debug("BTRFS: drop snapshot early exit\n");
9316                                 err = -EAGAIN;
9317                                 goto out_free;
9318                         }
9319
9320                         trans = btrfs_start_transaction(tree_root, 0);
9321                         if (IS_ERR(trans)) {
9322                                 err = PTR_ERR(trans);
9323                                 goto out_free;
9324                         }
9325                         if (block_rsv)
9326                                 trans->block_rsv = block_rsv;
9327                 }
9328         }
9329         btrfs_release_path(path);
9330         if (err)
9331                 goto out_end_trans;
9332
9333         ret = btrfs_del_root(trans, tree_root, &root->root_key);
9334         if (ret) {
9335                 btrfs_abort_transaction(trans, ret);
9336                 goto out_end_trans;
9337         }
9338
9339         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9340                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9341                                       NULL, NULL);
9342                 if (ret < 0) {
9343                         btrfs_abort_transaction(trans, ret);
9344                         err = ret;
9345                         goto out_end_trans;
9346                 } else if (ret > 0) {
9347                         /* if we fail to delete the orphan item this time
9348                          * around, it'll get picked up the next time.
9349                          *
9350                          * The most common failure here is just -ENOENT.
9351                          */
9352                         btrfs_del_orphan_item(trans, tree_root,
9353                                               root->root_key.objectid);
9354                 }
9355         }
9356
9357         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9358                 btrfs_add_dropped_root(trans, root);
9359         } else {
9360                 free_extent_buffer(root->node);
9361                 free_extent_buffer(root->commit_root);
9362                 btrfs_put_fs_root(root);
9363         }
9364         root_dropped = true;
9365 out_end_trans:
9366         btrfs_end_transaction_throttle(trans, tree_root);
9367 out_free:
9368         kfree(wc);
9369         btrfs_free_path(path);
9370 out:
9371         /*
9372          * So if we need to stop dropping the snapshot for whatever reason we
9373          * need to make sure to add it back to the dead root list so that we
9374          * keep trying to do the work later.  This also cleans up roots if we
9375          * don't have it in the radix (like when we recover after a power fail
9376          * or unmount) so we don't leak memory.
9377          */
9378         if (!for_reloc && root_dropped == false)
9379                 btrfs_add_dead_root(root);
9380         if (err && err != -EAGAIN)
9381                 btrfs_handle_fs_error(root->fs_info, err, NULL);
9382         return err;
9383 }
9384
9385 /*
9386  * drop subtree rooted at tree block 'node'.
9387  *
9388  * NOTE: this function will unlock and release tree block 'node'
9389  * only used by relocation code
9390  */
9391 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9392                         struct btrfs_root *root,
9393                         struct extent_buffer *node,
9394                         struct extent_buffer *parent)
9395 {
9396         struct btrfs_path *path;
9397         struct walk_control *wc;
9398         int level;
9399         int parent_level;
9400         int ret = 0;
9401         int wret;
9402
9403         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9404
9405         path = btrfs_alloc_path();
9406         if (!path)
9407                 return -ENOMEM;
9408
9409         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9410         if (!wc) {
9411                 btrfs_free_path(path);
9412                 return -ENOMEM;
9413         }
9414
9415         btrfs_assert_tree_locked(parent);
9416         parent_level = btrfs_header_level(parent);
9417         extent_buffer_get(parent);
9418         path->nodes[parent_level] = parent;
9419         path->slots[parent_level] = btrfs_header_nritems(parent);
9420
9421         btrfs_assert_tree_locked(node);
9422         level = btrfs_header_level(node);
9423         path->nodes[level] = node;
9424         path->slots[level] = 0;
9425         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9426
9427         wc->refs[parent_level] = 1;
9428         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9429         wc->level = level;
9430         wc->shared_level = -1;
9431         wc->stage = DROP_REFERENCE;
9432         wc->update_ref = 0;
9433         wc->keep_locks = 1;
9434         wc->for_reloc = 1;
9435         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9436
9437         while (1) {
9438                 wret = walk_down_tree(trans, root, path, wc);
9439                 if (wret < 0) {
9440                         ret = wret;
9441                         break;
9442                 }
9443
9444                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9445                 if (wret < 0)
9446                         ret = wret;
9447                 if (wret != 0)
9448                         break;
9449         }
9450
9451         kfree(wc);
9452         btrfs_free_path(path);
9453         return ret;
9454 }
9455
9456 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
9457 {
9458         u64 num_devices;
9459         u64 stripped;
9460
9461         /*
9462          * if restripe for this chunk_type is on pick target profile and
9463          * return, otherwise do the usual balance
9464          */
9465         stripped = get_restripe_target(root->fs_info, flags);
9466         if (stripped)
9467                 return extended_to_chunk(stripped);
9468
9469         num_devices = root->fs_info->fs_devices->rw_devices;
9470
9471         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9472                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9473                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9474
9475         if (num_devices == 1) {
9476                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9477                 stripped = flags & ~stripped;
9478
9479                 /* turn raid0 into single device chunks */
9480                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9481                         return stripped;
9482
9483                 /* turn mirroring into duplication */
9484                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9485                              BTRFS_BLOCK_GROUP_RAID10))
9486                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9487         } else {
9488                 /* they already had raid on here, just return */
9489                 if (flags & stripped)
9490                         return flags;
9491
9492                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9493                 stripped = flags & ~stripped;
9494
9495                 /* switch duplicated blocks with raid1 */
9496                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9497                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9498
9499                 /* this is drive concat, leave it alone */
9500         }
9501
9502         return flags;
9503 }
9504
9505 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9506 {
9507         struct btrfs_space_info *sinfo = cache->space_info;
9508         u64 num_bytes;
9509         u64 min_allocable_bytes;
9510         int ret = -ENOSPC;
9511
9512         /*
9513          * We need some metadata space and system metadata space for
9514          * allocating chunks in some corner cases until we force to set
9515          * it to be readonly.
9516          */
9517         if ((sinfo->flags &
9518              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9519             !force)
9520                 min_allocable_bytes = SZ_1M;
9521         else
9522                 min_allocable_bytes = 0;
9523
9524         spin_lock(&sinfo->lock);
9525         spin_lock(&cache->lock);
9526
9527         if (cache->ro) {
9528                 cache->ro++;
9529                 ret = 0;
9530                 goto out;
9531         }
9532
9533         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9534                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9535
9536         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
9537             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
9538             min_allocable_bytes <= sinfo->total_bytes) {
9539                 sinfo->bytes_readonly += num_bytes;
9540                 cache->ro++;
9541                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9542                 ret = 0;
9543         }
9544 out:
9545         spin_unlock(&cache->lock);
9546         spin_unlock(&sinfo->lock);
9547         return ret;
9548 }
9549
9550 int btrfs_inc_block_group_ro(struct btrfs_root *root,
9551                              struct btrfs_block_group_cache *cache)
9552
9553 {
9554         struct btrfs_trans_handle *trans;
9555         u64 alloc_flags;
9556         int ret;
9557
9558 again:
9559         trans = btrfs_join_transaction(root);
9560         if (IS_ERR(trans))
9561                 return PTR_ERR(trans);
9562
9563         /*
9564          * we're not allowed to set block groups readonly after the dirty
9565          * block groups cache has started writing.  If it already started,
9566          * back off and let this transaction commit
9567          */
9568         mutex_lock(&root->fs_info->ro_block_group_mutex);
9569         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9570                 u64 transid = trans->transid;
9571
9572                 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9573                 btrfs_end_transaction(trans, root);
9574
9575                 ret = btrfs_wait_for_commit(root, transid);
9576                 if (ret)
9577                         return ret;
9578                 goto again;
9579         }
9580
9581         /*
9582          * if we are changing raid levels, try to allocate a corresponding
9583          * block group with the new raid level.
9584          */
9585         alloc_flags = update_block_group_flags(root, cache->flags);
9586         if (alloc_flags != cache->flags) {
9587                 ret = do_chunk_alloc(trans, root, alloc_flags,
9588                                      CHUNK_ALLOC_FORCE);
9589                 /*
9590                  * ENOSPC is allowed here, we may have enough space
9591                  * already allocated at the new raid level to
9592                  * carry on
9593                  */
9594                 if (ret == -ENOSPC)
9595                         ret = 0;
9596                 if (ret < 0)
9597                         goto out;
9598         }
9599
9600         ret = inc_block_group_ro(cache, 0);
9601         if (!ret)
9602                 goto out;
9603         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
9604         ret = do_chunk_alloc(trans, root, alloc_flags,
9605                              CHUNK_ALLOC_FORCE);
9606         if (ret < 0)
9607                 goto out;
9608         ret = inc_block_group_ro(cache, 0);
9609 out:
9610         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9611                 alloc_flags = update_block_group_flags(root, cache->flags);
9612                 lock_chunks(root->fs_info->chunk_root);
9613                 check_system_chunk(trans, root, alloc_flags);
9614                 unlock_chunks(root->fs_info->chunk_root);
9615         }
9616         mutex_unlock(&root->fs_info->ro_block_group_mutex);
9617
9618         btrfs_end_transaction(trans, root);
9619         return ret;
9620 }
9621
9622 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9623                             struct btrfs_root *root, u64 type)
9624 {
9625         u64 alloc_flags = get_alloc_profile(root, type);
9626         return do_chunk_alloc(trans, root, alloc_flags,
9627                               CHUNK_ALLOC_FORCE);
9628 }
9629
9630 /*
9631  * helper to account the unused space of all the readonly block group in the
9632  * space_info. takes mirrors into account.
9633  */
9634 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9635 {
9636         struct btrfs_block_group_cache *block_group;
9637         u64 free_bytes = 0;
9638         int factor;
9639
9640         /* It's df, we don't care if it's racy */
9641         if (list_empty(&sinfo->ro_bgs))
9642                 return 0;
9643
9644         spin_lock(&sinfo->lock);
9645         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9646                 spin_lock(&block_group->lock);
9647
9648                 if (!block_group->ro) {
9649                         spin_unlock(&block_group->lock);
9650                         continue;
9651                 }
9652
9653                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9654                                           BTRFS_BLOCK_GROUP_RAID10 |
9655                                           BTRFS_BLOCK_GROUP_DUP))
9656                         factor = 2;
9657                 else
9658                         factor = 1;
9659
9660                 free_bytes += (block_group->key.offset -
9661                                btrfs_block_group_used(&block_group->item)) *
9662                                factor;
9663
9664                 spin_unlock(&block_group->lock);
9665         }
9666         spin_unlock(&sinfo->lock);
9667
9668         return free_bytes;
9669 }
9670
9671 void btrfs_dec_block_group_ro(struct btrfs_root *root,
9672                               struct btrfs_block_group_cache *cache)
9673 {
9674         struct btrfs_space_info *sinfo = cache->space_info;
9675         u64 num_bytes;
9676
9677         BUG_ON(!cache->ro);
9678
9679         spin_lock(&sinfo->lock);
9680         spin_lock(&cache->lock);
9681         if (!--cache->ro) {
9682                 num_bytes = cache->key.offset - cache->reserved -
9683                             cache->pinned - cache->bytes_super -
9684                             btrfs_block_group_used(&cache->item);
9685                 sinfo->bytes_readonly -= num_bytes;
9686                 list_del_init(&cache->ro_list);
9687         }
9688         spin_unlock(&cache->lock);
9689         spin_unlock(&sinfo->lock);
9690 }
9691
9692 /*
9693  * checks to see if its even possible to relocate this block group.
9694  *
9695  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9696  * ok to go ahead and try.
9697  */
9698 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
9699 {
9700         struct btrfs_block_group_cache *block_group;
9701         struct btrfs_space_info *space_info;
9702         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
9703         struct btrfs_device *device;
9704         struct btrfs_trans_handle *trans;
9705         u64 min_free;
9706         u64 dev_min = 1;
9707         u64 dev_nr = 0;
9708         u64 target;
9709         int debug;
9710         int index;
9711         int full = 0;
9712         int ret = 0;
9713
9714         debug = btrfs_test_opt(root->fs_info, ENOSPC_DEBUG);
9715
9716         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
9717
9718         /* odd, couldn't find the block group, leave it alone */
9719         if (!block_group) {
9720                 if (debug)
9721                         btrfs_warn(root->fs_info,
9722                                    "can't find block group for bytenr %llu",
9723                                    bytenr);
9724                 return -1;
9725         }
9726
9727         min_free = btrfs_block_group_used(&block_group->item);
9728
9729         /* no bytes used, we're good */
9730         if (!min_free)
9731                 goto out;
9732
9733         space_info = block_group->space_info;
9734         spin_lock(&space_info->lock);
9735
9736         full = space_info->full;
9737
9738         /*
9739          * if this is the last block group we have in this space, we can't
9740          * relocate it unless we're able to allocate a new chunk below.
9741          *
9742          * Otherwise, we need to make sure we have room in the space to handle
9743          * all of the extents from this block group.  If we can, we're good
9744          */
9745         if ((space_info->total_bytes != block_group->key.offset) &&
9746             (space_info->bytes_used + space_info->bytes_reserved +
9747              space_info->bytes_pinned + space_info->bytes_readonly +
9748              min_free < space_info->total_bytes)) {
9749                 spin_unlock(&space_info->lock);
9750                 goto out;
9751         }
9752         spin_unlock(&space_info->lock);
9753
9754         /*
9755          * ok we don't have enough space, but maybe we have free space on our
9756          * devices to allocate new chunks for relocation, so loop through our
9757          * alloc devices and guess if we have enough space.  if this block
9758          * group is going to be restriped, run checks against the target
9759          * profile instead of the current one.
9760          */
9761         ret = -1;
9762
9763         /*
9764          * index:
9765          *      0: raid10
9766          *      1: raid1
9767          *      2: dup
9768          *      3: raid0
9769          *      4: single
9770          */
9771         target = get_restripe_target(root->fs_info, block_group->flags);
9772         if (target) {
9773                 index = __get_raid_index(extended_to_chunk(target));
9774         } else {
9775                 /*
9776                  * this is just a balance, so if we were marked as full
9777                  * we know there is no space for a new chunk
9778                  */
9779                 if (full) {
9780                         if (debug)
9781                                 btrfs_warn(root->fs_info,
9782                                         "no space to alloc new chunk for block group %llu",
9783                                         block_group->key.objectid);
9784                         goto out;
9785                 }
9786
9787                 index = get_block_group_index(block_group);
9788         }
9789
9790         if (index == BTRFS_RAID_RAID10) {
9791                 dev_min = 4;
9792                 /* Divide by 2 */
9793                 min_free >>= 1;
9794         } else if (index == BTRFS_RAID_RAID1) {
9795                 dev_min = 2;
9796         } else if (index == BTRFS_RAID_DUP) {
9797                 /* Multiply by 2 */
9798                 min_free <<= 1;
9799         } else if (index == BTRFS_RAID_RAID0) {
9800                 dev_min = fs_devices->rw_devices;
9801                 min_free = div64_u64(min_free, dev_min);
9802         }
9803
9804         /* We need to do this so that we can look at pending chunks */
9805         trans = btrfs_join_transaction(root);
9806         if (IS_ERR(trans)) {
9807                 ret = PTR_ERR(trans);
9808                 goto out;
9809         }
9810
9811         mutex_lock(&root->fs_info->chunk_mutex);
9812         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9813                 u64 dev_offset;
9814
9815                 /*
9816                  * check to make sure we can actually find a chunk with enough
9817                  * space to fit our block group in.
9818                  */
9819                 if (device->total_bytes > device->bytes_used + min_free &&
9820                     !device->is_tgtdev_for_dev_replace) {
9821                         ret = find_free_dev_extent(trans, device, min_free,
9822                                                    &dev_offset, NULL);
9823                         if (!ret)
9824                                 dev_nr++;
9825
9826                         if (dev_nr >= dev_min)
9827                                 break;
9828
9829                         ret = -1;
9830                 }
9831         }
9832         if (debug && ret == -1)
9833                 btrfs_warn(root->fs_info,
9834                         "no space to allocate a new chunk for block group %llu",
9835                         block_group->key.objectid);
9836         mutex_unlock(&root->fs_info->chunk_mutex);
9837         btrfs_end_transaction(trans, root);
9838 out:
9839         btrfs_put_block_group(block_group);
9840         return ret;
9841 }
9842
9843 static int find_first_block_group(struct btrfs_root *root,
9844                 struct btrfs_path *path, struct btrfs_key *key)
9845 {
9846         int ret = 0;
9847         struct btrfs_key found_key;
9848         struct extent_buffer *leaf;
9849         int slot;
9850
9851         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9852         if (ret < 0)
9853                 goto out;
9854
9855         while (1) {
9856                 slot = path->slots[0];
9857                 leaf = path->nodes[0];
9858                 if (slot >= btrfs_header_nritems(leaf)) {
9859                         ret = btrfs_next_leaf(root, path);
9860                         if (ret == 0)
9861                                 continue;
9862                         if (ret < 0)
9863                                 goto out;
9864                         break;
9865                 }
9866                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9867
9868                 if (found_key.objectid >= key->objectid &&
9869                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9870                         struct extent_map_tree *em_tree;
9871                         struct extent_map *em;
9872
9873                         em_tree = &root->fs_info->mapping_tree.map_tree;
9874                         read_lock(&em_tree->lock);
9875                         em = lookup_extent_mapping(em_tree, found_key.objectid,
9876                                                    found_key.offset);
9877                         read_unlock(&em_tree->lock);
9878                         if (!em) {
9879                                 btrfs_err(root->fs_info,
9880                         "logical %llu len %llu found bg but no related chunk",
9881                                           found_key.objectid, found_key.offset);
9882                                 ret = -ENOENT;
9883                         } else {
9884                                 ret = 0;
9885                         }
9886                         free_extent_map(em);
9887                         goto out;
9888                 }
9889                 path->slots[0]++;
9890         }
9891 out:
9892         return ret;
9893 }
9894
9895 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9896 {
9897         struct btrfs_block_group_cache *block_group;
9898         u64 last = 0;
9899
9900         while (1) {
9901                 struct inode *inode;
9902
9903                 block_group = btrfs_lookup_first_block_group(info, last);
9904                 while (block_group) {
9905                         spin_lock(&block_group->lock);
9906                         if (block_group->iref)
9907                                 break;
9908                         spin_unlock(&block_group->lock);
9909                         block_group = next_block_group(info->tree_root,
9910                                                        block_group);
9911                 }
9912                 if (!block_group) {
9913                         if (last == 0)
9914                                 break;
9915                         last = 0;
9916                         continue;
9917                 }
9918
9919                 inode = block_group->inode;
9920                 block_group->iref = 0;
9921                 block_group->inode = NULL;
9922                 spin_unlock(&block_group->lock);
9923                 ASSERT(block_group->io_ctl.inode == NULL);
9924                 iput(inode);
9925                 last = block_group->key.objectid + block_group->key.offset;
9926                 btrfs_put_block_group(block_group);
9927         }
9928 }
9929
9930 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9931 {
9932         struct btrfs_block_group_cache *block_group;
9933         struct btrfs_space_info *space_info;
9934         struct btrfs_caching_control *caching_ctl;
9935         struct rb_node *n;
9936
9937         down_write(&info->commit_root_sem);
9938         while (!list_empty(&info->caching_block_groups)) {
9939                 caching_ctl = list_entry(info->caching_block_groups.next,
9940                                          struct btrfs_caching_control, list);
9941                 list_del(&caching_ctl->list);
9942                 put_caching_control(caching_ctl);
9943         }
9944         up_write(&info->commit_root_sem);
9945
9946         spin_lock(&info->unused_bgs_lock);
9947         while (!list_empty(&info->unused_bgs)) {
9948                 block_group = list_first_entry(&info->unused_bgs,
9949                                                struct btrfs_block_group_cache,
9950                                                bg_list);
9951                 list_del_init(&block_group->bg_list);
9952                 btrfs_put_block_group(block_group);
9953         }
9954         spin_unlock(&info->unused_bgs_lock);
9955
9956         spin_lock(&info->block_group_cache_lock);
9957         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9958                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9959                                        cache_node);
9960                 rb_erase(&block_group->cache_node,
9961                          &info->block_group_cache_tree);
9962                 RB_CLEAR_NODE(&block_group->cache_node);
9963                 spin_unlock(&info->block_group_cache_lock);
9964
9965                 down_write(&block_group->space_info->groups_sem);
9966                 list_del(&block_group->list);
9967                 up_write(&block_group->space_info->groups_sem);
9968
9969                 if (block_group->cached == BTRFS_CACHE_STARTED)
9970                         wait_block_group_cache_done(block_group);
9971
9972                 /*
9973                  * We haven't cached this block group, which means we could
9974                  * possibly have excluded extents on this block group.
9975                  */
9976                 if (block_group->cached == BTRFS_CACHE_NO ||
9977                     block_group->cached == BTRFS_CACHE_ERROR)
9978                         free_excluded_extents(info->extent_root, block_group);
9979
9980                 btrfs_remove_free_space_cache(block_group);
9981                 ASSERT(list_empty(&block_group->dirty_list));
9982                 ASSERT(list_empty(&block_group->io_list));
9983                 ASSERT(list_empty(&block_group->bg_list));
9984                 ASSERT(atomic_read(&block_group->count) == 1);
9985                 btrfs_put_block_group(block_group);
9986
9987                 spin_lock(&info->block_group_cache_lock);
9988         }
9989         spin_unlock(&info->block_group_cache_lock);
9990
9991         /* now that all the block groups are freed, go through and
9992          * free all the space_info structs.  This is only called during
9993          * the final stages of unmount, and so we know nobody is
9994          * using them.  We call synchronize_rcu() once before we start,
9995          * just to be on the safe side.
9996          */
9997         synchronize_rcu();
9998
9999         release_global_block_rsv(info);
10000
10001         while (!list_empty(&info->space_info)) {
10002                 int i;
10003
10004                 space_info = list_entry(info->space_info.next,
10005                                         struct btrfs_space_info,
10006                                         list);
10007
10008                 /*
10009                  * Do not hide this behind enospc_debug, this is actually
10010                  * important and indicates a real bug if this happens.
10011                  */
10012                 if (WARN_ON(space_info->bytes_pinned > 0 ||
10013                             space_info->bytes_reserved > 0 ||
10014                             space_info->bytes_may_use > 0))
10015                         dump_space_info(space_info, 0, 0);
10016                 list_del(&space_info->list);
10017                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
10018                         struct kobject *kobj;
10019                         kobj = space_info->block_group_kobjs[i];
10020                         space_info->block_group_kobjs[i] = NULL;
10021                         if (kobj) {
10022                                 kobject_del(kobj);
10023                                 kobject_put(kobj);
10024                         }
10025                 }
10026                 kobject_del(&space_info->kobj);
10027                 kobject_put(&space_info->kobj);
10028         }
10029         return 0;
10030 }
10031
10032 static void __link_block_group(struct btrfs_space_info *space_info,
10033                                struct btrfs_block_group_cache *cache)
10034 {
10035         int index = get_block_group_index(cache);
10036         bool first = false;
10037
10038         down_write(&space_info->groups_sem);
10039         if (list_empty(&space_info->block_groups[index]))
10040                 first = true;
10041         list_add_tail(&cache->list, &space_info->block_groups[index]);
10042         up_write(&space_info->groups_sem);
10043
10044         if (first) {
10045                 struct raid_kobject *rkobj;
10046                 int ret;
10047
10048                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
10049                 if (!rkobj)
10050                         goto out_err;
10051                 rkobj->raid_type = index;
10052                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
10053                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
10054                                   "%s", get_raid_name(index));
10055                 if (ret) {
10056                         kobject_put(&rkobj->kobj);
10057                         goto out_err;
10058                 }
10059                 space_info->block_group_kobjs[index] = &rkobj->kobj;
10060         }
10061
10062         return;
10063 out_err:
10064         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
10065 }
10066
10067 static struct btrfs_block_group_cache *
10068 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
10069 {
10070         struct btrfs_block_group_cache *cache;
10071
10072         cache = kzalloc(sizeof(*cache), GFP_NOFS);
10073         if (!cache)
10074                 return NULL;
10075
10076         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
10077                                         GFP_NOFS);
10078         if (!cache->free_space_ctl) {
10079                 kfree(cache);
10080                 return NULL;
10081         }
10082
10083         cache->key.objectid = start;
10084         cache->key.offset = size;
10085         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10086
10087         cache->sectorsize = root->sectorsize;
10088         cache->fs_info = root->fs_info;
10089         cache->full_stripe_len = btrfs_full_stripe_len(root,
10090                                                &root->fs_info->mapping_tree,
10091                                                start);
10092         set_free_space_tree_thresholds(cache);
10093
10094         atomic_set(&cache->count, 1);
10095         spin_lock_init(&cache->lock);
10096         init_rwsem(&cache->data_rwsem);
10097         INIT_LIST_HEAD(&cache->list);
10098         INIT_LIST_HEAD(&cache->cluster_list);
10099         INIT_LIST_HEAD(&cache->bg_list);
10100         INIT_LIST_HEAD(&cache->ro_list);
10101         INIT_LIST_HEAD(&cache->dirty_list);
10102         INIT_LIST_HEAD(&cache->io_list);
10103         btrfs_init_free_space_ctl(cache);
10104         atomic_set(&cache->trimming, 0);
10105         mutex_init(&cache->free_space_lock);
10106
10107         return cache;
10108 }
10109
10110 int btrfs_read_block_groups(struct btrfs_root *root)
10111 {
10112         struct btrfs_path *path;
10113         int ret;
10114         struct btrfs_block_group_cache *cache;
10115         struct btrfs_fs_info *info = root->fs_info;
10116         struct btrfs_space_info *space_info;
10117         struct btrfs_key key;
10118         struct btrfs_key found_key;
10119         struct extent_buffer *leaf;
10120         int need_clear = 0;
10121         u64 cache_gen;
10122         u64 feature;
10123         int mixed;
10124
10125         feature = btrfs_super_incompat_flags(info->super_copy);
10126         mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
10127
10128         root = info->extent_root;
10129         key.objectid = 0;
10130         key.offset = 0;
10131         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10132         path = btrfs_alloc_path();
10133         if (!path)
10134                 return -ENOMEM;
10135         path->reada = READA_FORWARD;
10136
10137         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
10138         if (btrfs_test_opt(root->fs_info, SPACE_CACHE) &&
10139             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
10140                 need_clear = 1;
10141         if (btrfs_test_opt(root->fs_info, CLEAR_CACHE))
10142                 need_clear = 1;
10143
10144         while (1) {
10145                 ret = find_first_block_group(root, path, &key);
10146                 if (ret > 0)
10147                         break;
10148                 if (ret != 0)
10149                         goto error;
10150
10151                 leaf = path->nodes[0];
10152                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
10153
10154                 cache = btrfs_create_block_group_cache(root, found_key.objectid,
10155                                                        found_key.offset);
10156                 if (!cache) {
10157                         ret = -ENOMEM;
10158                         goto error;
10159                 }
10160
10161                 if (need_clear) {
10162                         /*
10163                          * When we mount with old space cache, we need to
10164                          * set BTRFS_DC_CLEAR and set dirty flag.
10165                          *
10166                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10167                          *    truncate the old free space cache inode and
10168                          *    setup a new one.
10169                          * b) Setting 'dirty flag' makes sure that we flush
10170                          *    the new space cache info onto disk.
10171                          */
10172                         if (btrfs_test_opt(root->fs_info, SPACE_CACHE))
10173                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
10174                 }
10175
10176                 read_extent_buffer(leaf, &cache->item,
10177                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
10178                                    sizeof(cache->item));
10179                 cache->flags = btrfs_block_group_flags(&cache->item);
10180                 if (!mixed &&
10181                     ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
10182                     (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
10183                         btrfs_err(info,
10184 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
10185                                   cache->key.objectid);
10186                         ret = -EINVAL;
10187                         goto error;
10188                 }
10189
10190                 key.objectid = found_key.objectid + found_key.offset;
10191                 btrfs_release_path(path);
10192
10193                 /*
10194                  * We need to exclude the super stripes now so that the space
10195                  * info has super bytes accounted for, otherwise we'll think
10196                  * we have more space than we actually do.
10197                  */
10198                 ret = exclude_super_stripes(root, cache);
10199                 if (ret) {
10200                         /*
10201                          * We may have excluded something, so call this just in
10202                          * case.
10203                          */
10204                         free_excluded_extents(root, cache);
10205                         btrfs_put_block_group(cache);
10206                         goto error;
10207                 }
10208
10209                 /*
10210                  * check for two cases, either we are full, and therefore
10211                  * don't need to bother with the caching work since we won't
10212                  * find any space, or we are empty, and we can just add all
10213                  * the space in and be done with it.  This saves us _alot_ of
10214                  * time, particularly in the full case.
10215                  */
10216                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10217                         cache->last_byte_to_unpin = (u64)-1;
10218                         cache->cached = BTRFS_CACHE_FINISHED;
10219                         free_excluded_extents(root, cache);
10220                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10221                         cache->last_byte_to_unpin = (u64)-1;
10222                         cache->cached = BTRFS_CACHE_FINISHED;
10223                         add_new_free_space(cache, root->fs_info,
10224                                            found_key.objectid,
10225                                            found_key.objectid +
10226                                            found_key.offset);
10227                         free_excluded_extents(root, cache);
10228                 }
10229
10230                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10231                 if (ret) {
10232                         btrfs_remove_free_space_cache(cache);
10233                         btrfs_put_block_group(cache);
10234                         goto error;
10235                 }
10236
10237                 trace_btrfs_add_block_group(root->fs_info, cache, 0);
10238                 ret = update_space_info(info, cache->flags, found_key.offset,
10239                                         btrfs_block_group_used(&cache->item),
10240                                         cache->bytes_super, &space_info);
10241                 if (ret) {
10242                         btrfs_remove_free_space_cache(cache);
10243                         spin_lock(&info->block_group_cache_lock);
10244                         rb_erase(&cache->cache_node,
10245                                  &info->block_group_cache_tree);
10246                         RB_CLEAR_NODE(&cache->cache_node);
10247                         spin_unlock(&info->block_group_cache_lock);
10248                         btrfs_put_block_group(cache);
10249                         goto error;
10250                 }
10251
10252                 cache->space_info = space_info;
10253
10254                 __link_block_group(space_info, cache);
10255
10256                 set_avail_alloc_bits(root->fs_info, cache->flags);
10257                 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
10258                         inc_block_group_ro(cache, 1);
10259                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10260                         spin_lock(&info->unused_bgs_lock);
10261                         /* Should always be true but just in case. */
10262                         if (list_empty(&cache->bg_list)) {
10263                                 btrfs_get_block_group(cache);
10264                                 list_add_tail(&cache->bg_list,
10265                                               &info->unused_bgs);
10266                         }
10267                         spin_unlock(&info->unused_bgs_lock);
10268                 }
10269         }
10270
10271         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
10272                 if (!(get_alloc_profile(root, space_info->flags) &
10273                       (BTRFS_BLOCK_GROUP_RAID10 |
10274                        BTRFS_BLOCK_GROUP_RAID1 |
10275                        BTRFS_BLOCK_GROUP_RAID5 |
10276                        BTRFS_BLOCK_GROUP_RAID6 |
10277                        BTRFS_BLOCK_GROUP_DUP)))
10278                         continue;
10279                 /*
10280                  * avoid allocating from un-mirrored block group if there are
10281                  * mirrored block groups.
10282                  */
10283                 list_for_each_entry(cache,
10284                                 &space_info->block_groups[BTRFS_RAID_RAID0],
10285                                 list)
10286                         inc_block_group_ro(cache, 1);
10287                 list_for_each_entry(cache,
10288                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
10289                                 list)
10290                         inc_block_group_ro(cache, 1);
10291         }
10292
10293         init_global_block_rsv(info);
10294         ret = 0;
10295 error:
10296         btrfs_free_path(path);
10297         return ret;
10298 }
10299
10300 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
10301                                        struct btrfs_root *root)
10302 {
10303         struct btrfs_block_group_cache *block_group, *tmp;
10304         struct btrfs_root *extent_root = root->fs_info->extent_root;
10305         struct btrfs_block_group_item item;
10306         struct btrfs_key key;
10307         int ret = 0;
10308         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10309
10310         trans->can_flush_pending_bgs = false;
10311         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10312                 if (ret)
10313                         goto next;
10314
10315                 spin_lock(&block_group->lock);
10316                 memcpy(&item, &block_group->item, sizeof(item));
10317                 memcpy(&key, &block_group->key, sizeof(key));
10318                 spin_unlock(&block_group->lock);
10319
10320                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10321                                         sizeof(item));
10322                 if (ret)
10323                         btrfs_abort_transaction(trans, ret);
10324                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
10325                                                key.objectid, key.offset);
10326                 if (ret)
10327                         btrfs_abort_transaction(trans, ret);
10328                 add_block_group_free_space(trans, root->fs_info, block_group);
10329                 /* already aborted the transaction if it failed. */
10330 next:
10331                 list_del_init(&block_group->bg_list);
10332         }
10333         trans->can_flush_pending_bgs = can_flush_pending_bgs;
10334 }
10335
10336 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10337                            struct btrfs_root *root, u64 bytes_used,
10338                            u64 type, u64 chunk_objectid, u64 chunk_offset,
10339                            u64 size)
10340 {
10341         int ret;
10342         struct btrfs_root *extent_root;
10343         struct btrfs_block_group_cache *cache;
10344         extent_root = root->fs_info->extent_root;
10345
10346         btrfs_set_log_full_commit(root->fs_info, trans);
10347
10348         cache = btrfs_create_block_group_cache(root, chunk_offset, size);
10349         if (!cache)
10350                 return -ENOMEM;
10351
10352         btrfs_set_block_group_used(&cache->item, bytes_used);
10353         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
10354         btrfs_set_block_group_flags(&cache->item, type);
10355
10356         cache->flags = type;
10357         cache->last_byte_to_unpin = (u64)-1;
10358         cache->cached = BTRFS_CACHE_FINISHED;
10359         cache->needs_free_space = 1;
10360         ret = exclude_super_stripes(root, cache);
10361         if (ret) {
10362                 /*
10363                  * We may have excluded something, so call this just in
10364                  * case.
10365                  */
10366                 free_excluded_extents(root, cache);
10367                 btrfs_put_block_group(cache);
10368                 return ret;
10369         }
10370
10371         add_new_free_space(cache, root->fs_info, chunk_offset,
10372                            chunk_offset + size);
10373
10374         free_excluded_extents(root, cache);
10375
10376 #ifdef CONFIG_BTRFS_DEBUG
10377         if (btrfs_should_fragment_free_space(root, cache)) {
10378                 u64 new_bytes_used = size - bytes_used;
10379
10380                 bytes_used += new_bytes_used >> 1;
10381                 fragment_free_space(root, cache);
10382         }
10383 #endif
10384         /*
10385          * Call to ensure the corresponding space_info object is created and
10386          * assigned to our block group, but don't update its counters just yet.
10387          * We want our bg to be added to the rbtree with its ->space_info set.
10388          */
10389         ret = update_space_info(root->fs_info, cache->flags, 0, 0, 0,
10390                                 &cache->space_info);
10391         if (ret) {
10392                 btrfs_remove_free_space_cache(cache);
10393                 btrfs_put_block_group(cache);
10394                 return ret;
10395         }
10396
10397         ret = btrfs_add_block_group_cache(root->fs_info, cache);
10398         if (ret) {
10399                 btrfs_remove_free_space_cache(cache);
10400                 btrfs_put_block_group(cache);
10401                 return ret;
10402         }
10403
10404         /*
10405          * Now that our block group has its ->space_info set and is inserted in
10406          * the rbtree, update the space info's counters.
10407          */
10408         trace_btrfs_add_block_group(root->fs_info, cache, 1);
10409         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
10410                                 cache->bytes_super, &cache->space_info);
10411         if (ret) {
10412                 btrfs_remove_free_space_cache(cache);
10413                 spin_lock(&root->fs_info->block_group_cache_lock);
10414                 rb_erase(&cache->cache_node,
10415                          &root->fs_info->block_group_cache_tree);
10416                 RB_CLEAR_NODE(&cache->cache_node);
10417                 spin_unlock(&root->fs_info->block_group_cache_lock);
10418                 btrfs_put_block_group(cache);
10419                 return ret;
10420         }
10421         update_global_block_rsv(root->fs_info);
10422
10423         __link_block_group(cache->space_info, cache);
10424
10425         list_add_tail(&cache->bg_list, &trans->new_bgs);
10426
10427         set_avail_alloc_bits(extent_root->fs_info, type);
10428         return 0;
10429 }
10430
10431 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10432 {
10433         u64 extra_flags = chunk_to_extended(flags) &
10434                                 BTRFS_EXTENDED_PROFILE_MASK;
10435
10436         write_seqlock(&fs_info->profiles_lock);
10437         if (flags & BTRFS_BLOCK_GROUP_DATA)
10438                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10439         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10440                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10441         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10442                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10443         write_sequnlock(&fs_info->profiles_lock);
10444 }
10445
10446 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10447                              struct btrfs_root *root, u64 group_start,
10448                              struct extent_map *em)
10449 {
10450         struct btrfs_path *path;
10451         struct btrfs_block_group_cache *block_group;
10452         struct btrfs_free_cluster *cluster;
10453         struct btrfs_root *tree_root = root->fs_info->tree_root;
10454         struct btrfs_key key;
10455         struct inode *inode;
10456         struct kobject *kobj = NULL;
10457         int ret;
10458         int index;
10459         int factor;
10460         struct btrfs_caching_control *caching_ctl = NULL;
10461         bool remove_em;
10462
10463         root = root->fs_info->extent_root;
10464
10465         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
10466         BUG_ON(!block_group);
10467         BUG_ON(!block_group->ro);
10468
10469         /*
10470          * Free the reserved super bytes from this block group before
10471          * remove it.
10472          */
10473         free_excluded_extents(root, block_group);
10474
10475         memcpy(&key, &block_group->key, sizeof(key));
10476         index = get_block_group_index(block_group);
10477         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10478                                   BTRFS_BLOCK_GROUP_RAID1 |
10479                                   BTRFS_BLOCK_GROUP_RAID10))
10480                 factor = 2;
10481         else
10482                 factor = 1;
10483
10484         /* make sure this block group isn't part of an allocation cluster */
10485         cluster = &root->fs_info->data_alloc_cluster;
10486         spin_lock(&cluster->refill_lock);
10487         btrfs_return_cluster_to_free_space(block_group, cluster);
10488         spin_unlock(&cluster->refill_lock);
10489
10490         /*
10491          * make sure this block group isn't part of a metadata
10492          * allocation cluster
10493          */
10494         cluster = &root->fs_info->meta_alloc_cluster;
10495         spin_lock(&cluster->refill_lock);
10496         btrfs_return_cluster_to_free_space(block_group, cluster);
10497         spin_unlock(&cluster->refill_lock);
10498
10499         path = btrfs_alloc_path();
10500         if (!path) {
10501                 ret = -ENOMEM;
10502                 goto out;
10503         }
10504
10505         /*
10506          * get the inode first so any iput calls done for the io_list
10507          * aren't the final iput (no unlinks allowed now)
10508          */
10509         inode = lookup_free_space_inode(tree_root, block_group, path);
10510
10511         mutex_lock(&trans->transaction->cache_write_mutex);
10512         /*
10513          * make sure our free spache cache IO is done before remove the
10514          * free space inode
10515          */
10516         spin_lock(&trans->transaction->dirty_bgs_lock);
10517         if (!list_empty(&block_group->io_list)) {
10518                 list_del_init(&block_group->io_list);
10519
10520                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10521
10522                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10523                 btrfs_wait_cache_io(root, trans, block_group,
10524                                     &block_group->io_ctl, path,
10525                                     block_group->key.objectid);
10526                 btrfs_put_block_group(block_group);
10527                 spin_lock(&trans->transaction->dirty_bgs_lock);
10528         }
10529
10530         if (!list_empty(&block_group->dirty_list)) {
10531                 list_del_init(&block_group->dirty_list);
10532                 btrfs_put_block_group(block_group);
10533         }
10534         spin_unlock(&trans->transaction->dirty_bgs_lock);
10535         mutex_unlock(&trans->transaction->cache_write_mutex);
10536
10537         if (!IS_ERR(inode)) {
10538                 ret = btrfs_orphan_add(trans, inode);
10539                 if (ret) {
10540                         btrfs_add_delayed_iput(inode);
10541                         goto out;
10542                 }
10543                 clear_nlink(inode);
10544                 /* One for the block groups ref */
10545                 spin_lock(&block_group->lock);
10546                 if (block_group->iref) {
10547                         block_group->iref = 0;
10548                         block_group->inode = NULL;
10549                         spin_unlock(&block_group->lock);
10550                         iput(inode);
10551                 } else {
10552                         spin_unlock(&block_group->lock);
10553                 }
10554                 /* One for our lookup ref */
10555                 btrfs_add_delayed_iput(inode);
10556         }
10557
10558         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10559         key.offset = block_group->key.objectid;
10560         key.type = 0;
10561
10562         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10563         if (ret < 0)
10564                 goto out;
10565         if (ret > 0)
10566                 btrfs_release_path(path);
10567         if (ret == 0) {
10568                 ret = btrfs_del_item(trans, tree_root, path);
10569                 if (ret)
10570                         goto out;
10571                 btrfs_release_path(path);
10572         }
10573
10574         spin_lock(&root->fs_info->block_group_cache_lock);
10575         rb_erase(&block_group->cache_node,
10576                  &root->fs_info->block_group_cache_tree);
10577         RB_CLEAR_NODE(&block_group->cache_node);
10578
10579         if (root->fs_info->first_logical_byte == block_group->key.objectid)
10580                 root->fs_info->first_logical_byte = (u64)-1;
10581         spin_unlock(&root->fs_info->block_group_cache_lock);
10582
10583         down_write(&block_group->space_info->groups_sem);
10584         /*
10585          * we must use list_del_init so people can check to see if they
10586          * are still on the list after taking the semaphore
10587          */
10588         list_del_init(&block_group->list);
10589         if (list_empty(&block_group->space_info->block_groups[index])) {
10590                 kobj = block_group->space_info->block_group_kobjs[index];
10591                 block_group->space_info->block_group_kobjs[index] = NULL;
10592                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
10593         }
10594         up_write(&block_group->space_info->groups_sem);
10595         if (kobj) {
10596                 kobject_del(kobj);
10597                 kobject_put(kobj);
10598         }
10599
10600         if (block_group->has_caching_ctl)
10601                 caching_ctl = get_caching_control(block_group);
10602         if (block_group->cached == BTRFS_CACHE_STARTED)
10603                 wait_block_group_cache_done(block_group);
10604         if (block_group->has_caching_ctl) {
10605                 down_write(&root->fs_info->commit_root_sem);
10606                 if (!caching_ctl) {
10607                         struct btrfs_caching_control *ctl;
10608
10609                         list_for_each_entry(ctl,
10610                                     &root->fs_info->caching_block_groups, list)
10611                                 if (ctl->block_group == block_group) {
10612                                         caching_ctl = ctl;
10613                                         atomic_inc(&caching_ctl->count);
10614                                         break;
10615                                 }
10616                 }
10617                 if (caching_ctl)
10618                         list_del_init(&caching_ctl->list);
10619                 up_write(&root->fs_info->commit_root_sem);
10620                 if (caching_ctl) {
10621                         /* Once for the caching bgs list and once for us. */
10622                         put_caching_control(caching_ctl);
10623                         put_caching_control(caching_ctl);
10624                 }
10625         }
10626
10627         spin_lock(&trans->transaction->dirty_bgs_lock);
10628         if (!list_empty(&block_group->dirty_list)) {
10629                 WARN_ON(1);
10630         }
10631         if (!list_empty(&block_group->io_list)) {
10632                 WARN_ON(1);
10633         }
10634         spin_unlock(&trans->transaction->dirty_bgs_lock);
10635         btrfs_remove_free_space_cache(block_group);
10636
10637         spin_lock(&block_group->space_info->lock);
10638         list_del_init(&block_group->ro_list);
10639
10640         if (btrfs_test_opt(root->fs_info, ENOSPC_DEBUG)) {
10641                 WARN_ON(block_group->space_info->total_bytes
10642                         < block_group->key.offset);
10643                 WARN_ON(block_group->space_info->bytes_readonly
10644                         < block_group->key.offset);
10645                 WARN_ON(block_group->space_info->disk_total
10646                         < block_group->key.offset * factor);
10647         }
10648         block_group->space_info->total_bytes -= block_group->key.offset;
10649         block_group->space_info->bytes_readonly -= block_group->key.offset;
10650         block_group->space_info->disk_total -= block_group->key.offset * factor;
10651
10652         spin_unlock(&block_group->space_info->lock);
10653
10654         memcpy(&key, &block_group->key, sizeof(key));
10655
10656         lock_chunks(root);
10657         if (!list_empty(&em->list)) {
10658                 /* We're in the transaction->pending_chunks list. */
10659                 free_extent_map(em);
10660         }
10661         spin_lock(&block_group->lock);
10662         block_group->removed = 1;
10663         /*
10664          * At this point trimming can't start on this block group, because we
10665          * removed the block group from the tree fs_info->block_group_cache_tree
10666          * so no one can't find it anymore and even if someone already got this
10667          * block group before we removed it from the rbtree, they have already
10668          * incremented block_group->trimming - if they didn't, they won't find
10669          * any free space entries because we already removed them all when we
10670          * called btrfs_remove_free_space_cache().
10671          *
10672          * And we must not remove the extent map from the fs_info->mapping_tree
10673          * to prevent the same logical address range and physical device space
10674          * ranges from being reused for a new block group. This is because our
10675          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10676          * completely transactionless, so while it is trimming a range the
10677          * currently running transaction might finish and a new one start,
10678          * allowing for new block groups to be created that can reuse the same
10679          * physical device locations unless we take this special care.
10680          *
10681          * There may also be an implicit trim operation if the file system
10682          * is mounted with -odiscard. The same protections must remain
10683          * in place until the extents have been discarded completely when
10684          * the transaction commit has completed.
10685          */
10686         remove_em = (atomic_read(&block_group->trimming) == 0);
10687         /*
10688          * Make sure a trimmer task always sees the em in the pinned_chunks list
10689          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10690          * before checking block_group->removed).
10691          */
10692         if (!remove_em) {
10693                 /*
10694                  * Our em might be in trans->transaction->pending_chunks which
10695                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10696                  * and so is the fs_info->pinned_chunks list.
10697                  *
10698                  * So at this point we must be holding the chunk_mutex to avoid
10699                  * any races with chunk allocation (more specifically at
10700                  * volumes.c:contains_pending_extent()), to ensure it always
10701                  * sees the em, either in the pending_chunks list or in the
10702                  * pinned_chunks list.
10703                  */
10704                 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
10705         }
10706         spin_unlock(&block_group->lock);
10707
10708         if (remove_em) {
10709                 struct extent_map_tree *em_tree;
10710
10711                 em_tree = &root->fs_info->mapping_tree.map_tree;
10712                 write_lock(&em_tree->lock);
10713                 /*
10714                  * The em might be in the pending_chunks list, so make sure the
10715                  * chunk mutex is locked, since remove_extent_mapping() will
10716                  * delete us from that list.
10717                  */
10718                 remove_extent_mapping(em_tree, em);
10719                 write_unlock(&em_tree->lock);
10720                 /* once for the tree */
10721                 free_extent_map(em);
10722         }
10723
10724         unlock_chunks(root);
10725
10726         ret = remove_block_group_free_space(trans, root->fs_info, block_group);
10727         if (ret)
10728                 goto out;
10729
10730         btrfs_put_block_group(block_group);
10731         btrfs_put_block_group(block_group);
10732
10733         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10734         if (ret > 0)
10735                 ret = -EIO;
10736         if (ret < 0)
10737                 goto out;
10738
10739         ret = btrfs_del_item(trans, root, path);
10740 out:
10741         btrfs_free_path(path);
10742         return ret;
10743 }
10744
10745 struct btrfs_trans_handle *
10746 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10747                                      const u64 chunk_offset)
10748 {
10749         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10750         struct extent_map *em;
10751         struct map_lookup *map;
10752         unsigned int num_items;
10753
10754         read_lock(&em_tree->lock);
10755         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10756         read_unlock(&em_tree->lock);
10757         ASSERT(em && em->start == chunk_offset);
10758
10759         /*
10760          * We need to reserve 3 + N units from the metadata space info in order
10761          * to remove a block group (done at btrfs_remove_chunk() and at
10762          * btrfs_remove_block_group()), which are used for:
10763          *
10764          * 1 unit for adding the free space inode's orphan (located in the tree
10765          * of tree roots).
10766          * 1 unit for deleting the block group item (located in the extent
10767          * tree).
10768          * 1 unit for deleting the free space item (located in tree of tree
10769          * roots).
10770          * N units for deleting N device extent items corresponding to each
10771          * stripe (located in the device tree).
10772          *
10773          * In order to remove a block group we also need to reserve units in the
10774          * system space info in order to update the chunk tree (update one or
10775          * more device items and remove one chunk item), but this is done at
10776          * btrfs_remove_chunk() through a call to check_system_chunk().
10777          */
10778         map = em->map_lookup;
10779         num_items = 3 + map->num_stripes;
10780         free_extent_map(em);
10781
10782         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10783                                                            num_items, 1);
10784 }
10785
10786 /*
10787  * Process the unused_bgs list and remove any that don't have any allocated
10788  * space inside of them.
10789  */
10790 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10791 {
10792         struct btrfs_block_group_cache *block_group;
10793         struct btrfs_space_info *space_info;
10794         struct btrfs_root *root = fs_info->extent_root;
10795         struct btrfs_trans_handle *trans;
10796         int ret = 0;
10797
10798         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10799                 return;
10800
10801         spin_lock(&fs_info->unused_bgs_lock);
10802         while (!list_empty(&fs_info->unused_bgs)) {
10803                 u64 start, end;
10804                 int trimming;
10805
10806                 block_group = list_first_entry(&fs_info->unused_bgs,
10807                                                struct btrfs_block_group_cache,
10808                                                bg_list);
10809                 list_del_init(&block_group->bg_list);
10810
10811                 space_info = block_group->space_info;
10812
10813                 if (ret || btrfs_mixed_space_info(space_info)) {
10814                         btrfs_put_block_group(block_group);
10815                         continue;
10816                 }
10817                 spin_unlock(&fs_info->unused_bgs_lock);
10818
10819                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10820
10821                 /* Don't want to race with allocators so take the groups_sem */
10822                 down_write(&space_info->groups_sem);
10823                 spin_lock(&block_group->lock);
10824                 if (block_group->reserved ||
10825                     btrfs_block_group_used(&block_group->item) ||
10826                     (block_group->ro && !block_group->removed) ||
10827                     list_is_singular(&block_group->list)) {
10828                         /*
10829                          * We want to bail if we made new allocations or have
10830                          * outstanding allocations in this block group.  We do
10831                          * the ro check in case balance is currently acting on
10832                          * this block group.
10833                          */
10834                         spin_unlock(&block_group->lock);
10835                         up_write(&space_info->groups_sem);
10836                         goto next;
10837                 }
10838                 spin_unlock(&block_group->lock);
10839
10840                 /* We don't want to force the issue, only flip if it's ok. */
10841                 ret = inc_block_group_ro(block_group, 0);
10842                 up_write(&space_info->groups_sem);
10843                 if (ret < 0) {
10844                         ret = 0;
10845                         goto next;
10846                 }
10847
10848                 /*
10849                  * Want to do this before we do anything else so we can recover
10850                  * properly if we fail to join the transaction.
10851                  */
10852                 trans = btrfs_start_trans_remove_block_group(fs_info,
10853                                                      block_group->key.objectid);
10854                 if (IS_ERR(trans)) {
10855                         btrfs_dec_block_group_ro(root, block_group);
10856                         ret = PTR_ERR(trans);
10857                         goto next;
10858                 }
10859
10860                 /*
10861                  * We could have pending pinned extents for this block group,
10862                  * just delete them, we don't care about them anymore.
10863                  */
10864                 start = block_group->key.objectid;
10865                 end = start + block_group->key.offset - 1;
10866                 /*
10867                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10868                  * btrfs_finish_extent_commit(). If we are at transaction N,
10869                  * another task might be running finish_extent_commit() for the
10870                  * previous transaction N - 1, and have seen a range belonging
10871                  * to the block group in freed_extents[] before we were able to
10872                  * clear the whole block group range from freed_extents[]. This
10873                  * means that task can lookup for the block group after we
10874                  * unpinned it from freed_extents[] and removed it, leading to
10875                  * a BUG_ON() at btrfs_unpin_extent_range().
10876                  */
10877                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10878                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10879                                   EXTENT_DIRTY);
10880                 if (ret) {
10881                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10882                         btrfs_dec_block_group_ro(root, block_group);
10883                         goto end_trans;
10884                 }
10885                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10886                                   EXTENT_DIRTY);
10887                 if (ret) {
10888                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10889                         btrfs_dec_block_group_ro(root, block_group);
10890                         goto end_trans;
10891                 }
10892                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10893
10894                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10895                 spin_lock(&space_info->lock);
10896                 spin_lock(&block_group->lock);
10897
10898                 space_info->bytes_pinned -= block_group->pinned;
10899                 space_info->bytes_readonly += block_group->pinned;
10900                 percpu_counter_add(&space_info->total_bytes_pinned,
10901                                    -block_group->pinned);
10902                 block_group->pinned = 0;
10903
10904                 spin_unlock(&block_group->lock);
10905                 spin_unlock(&space_info->lock);
10906
10907                 /* DISCARD can flip during remount */
10908                 trimming = btrfs_test_opt(root->fs_info, DISCARD);
10909
10910                 /* Implicit trim during transaction commit. */
10911                 if (trimming)
10912                         btrfs_get_block_group_trimming(block_group);
10913
10914                 /*
10915                  * Btrfs_remove_chunk will abort the transaction if things go
10916                  * horribly wrong.
10917                  */
10918                 ret = btrfs_remove_chunk(trans, root,
10919                                          block_group->key.objectid);
10920
10921                 if (ret) {
10922                         if (trimming)
10923                                 btrfs_put_block_group_trimming(block_group);
10924                         goto end_trans;
10925                 }
10926
10927                 /*
10928                  * If we're not mounted with -odiscard, we can just forget
10929                  * about this block group. Otherwise we'll need to wait
10930                  * until transaction commit to do the actual discard.
10931                  */
10932                 if (trimming) {
10933                         spin_lock(&fs_info->unused_bgs_lock);
10934                         /*
10935                          * A concurrent scrub might have added us to the list
10936                          * fs_info->unused_bgs, so use a list_move operation
10937                          * to add the block group to the deleted_bgs list.
10938                          */
10939                         list_move(&block_group->bg_list,
10940                                   &trans->transaction->deleted_bgs);
10941                         spin_unlock(&fs_info->unused_bgs_lock);
10942                         btrfs_get_block_group(block_group);
10943                 }
10944 end_trans:
10945                 btrfs_end_transaction(trans, root);
10946 next:
10947                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10948                 btrfs_put_block_group(block_group);
10949                 spin_lock(&fs_info->unused_bgs_lock);
10950         }
10951         spin_unlock(&fs_info->unused_bgs_lock);
10952 }
10953
10954 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10955 {
10956         struct btrfs_space_info *space_info;
10957         struct btrfs_super_block *disk_super;
10958         u64 features;
10959         u64 flags;
10960         int mixed = 0;
10961         int ret;
10962
10963         disk_super = fs_info->super_copy;
10964         if (!btrfs_super_root(disk_super))
10965                 return -EINVAL;
10966
10967         features = btrfs_super_incompat_flags(disk_super);
10968         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10969                 mixed = 1;
10970
10971         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10972         ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10973         if (ret)
10974                 goto out;
10975
10976         if (mixed) {
10977                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10978                 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10979         } else {
10980                 flags = BTRFS_BLOCK_GROUP_METADATA;
10981                 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10982                 if (ret)
10983                         goto out;
10984
10985                 flags = BTRFS_BLOCK_GROUP_DATA;
10986                 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10987         }
10988 out:
10989         return ret;
10990 }
10991
10992 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
10993 {
10994         return unpin_extent_range(root, start, end, false);
10995 }
10996
10997 /*
10998  * It used to be that old block groups would be left around forever.
10999  * Iterating over them would be enough to trim unused space.  Since we
11000  * now automatically remove them, we also need to iterate over unallocated
11001  * space.
11002  *
11003  * We don't want a transaction for this since the discard may take a
11004  * substantial amount of time.  We don't require that a transaction be
11005  * running, but we do need to take a running transaction into account
11006  * to ensure that we're not discarding chunks that were released in
11007  * the current transaction.
11008  *
11009  * Holding the chunks lock will prevent other threads from allocating
11010  * or releasing chunks, but it won't prevent a running transaction
11011  * from committing and releasing the memory that the pending chunks
11012  * list head uses.  For that, we need to take a reference to the
11013  * transaction.
11014  */
11015 static int btrfs_trim_free_extents(struct btrfs_device *device,
11016                                    u64 minlen, u64 *trimmed)
11017 {
11018         u64 start = 0, len = 0;
11019         int ret;
11020
11021         *trimmed = 0;
11022
11023         /* Not writeable = nothing to do. */
11024         if (!device->writeable)
11025                 return 0;
11026
11027         /* No free space = nothing to do. */
11028         if (device->total_bytes <= device->bytes_used)
11029                 return 0;
11030
11031         ret = 0;
11032
11033         while (1) {
11034                 struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
11035                 struct btrfs_transaction *trans;
11036                 u64 bytes;
11037
11038                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
11039                 if (ret)
11040                         return ret;
11041
11042                 down_read(&fs_info->commit_root_sem);
11043
11044                 spin_lock(&fs_info->trans_lock);
11045                 trans = fs_info->running_transaction;
11046                 if (trans)
11047                         atomic_inc(&trans->use_count);
11048                 spin_unlock(&fs_info->trans_lock);
11049
11050                 ret = find_free_dev_extent_start(trans, device, minlen, start,
11051                                                  &start, &len);
11052                 if (trans)
11053                         btrfs_put_transaction(trans);
11054
11055                 if (ret) {
11056                         up_read(&fs_info->commit_root_sem);
11057                         mutex_unlock(&fs_info->chunk_mutex);
11058                         if (ret == -ENOSPC)
11059                                 ret = 0;
11060                         break;
11061                 }
11062
11063                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
11064                 up_read(&fs_info->commit_root_sem);
11065                 mutex_unlock(&fs_info->chunk_mutex);
11066
11067                 if (ret)
11068                         break;
11069
11070                 start += len;
11071                 *trimmed += bytes;
11072
11073                 if (fatal_signal_pending(current)) {
11074                         ret = -ERESTARTSYS;
11075                         break;
11076                 }
11077
11078                 cond_resched();
11079         }
11080
11081         return ret;
11082 }
11083
11084 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
11085 {
11086         struct btrfs_fs_info *fs_info = root->fs_info;
11087         struct btrfs_block_group_cache *cache = NULL;
11088         struct btrfs_device *device;
11089         struct list_head *devices;
11090         u64 group_trimmed;
11091         u64 start;
11092         u64 end;
11093         u64 trimmed = 0;
11094         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
11095         int ret = 0;
11096
11097         /*
11098          * try to trim all FS space, our block group may start from non-zero.
11099          */
11100         if (range->len == total_bytes)
11101                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
11102         else
11103                 cache = btrfs_lookup_block_group(fs_info, range->start);
11104
11105         while (cache) {
11106                 if (cache->key.objectid >= (range->start + range->len)) {
11107                         btrfs_put_block_group(cache);
11108                         break;
11109                 }
11110
11111                 start = max(range->start, cache->key.objectid);
11112                 end = min(range->start + range->len,
11113                                 cache->key.objectid + cache->key.offset);
11114
11115                 if (end - start >= range->minlen) {
11116                         if (!block_group_cache_done(cache)) {
11117                                 ret = cache_block_group(cache, 0);
11118                                 if (ret) {
11119                                         btrfs_put_block_group(cache);
11120                                         break;
11121                                 }
11122                                 ret = wait_block_group_cache_done(cache);
11123                                 if (ret) {
11124                                         btrfs_put_block_group(cache);
11125                                         break;
11126                                 }
11127                         }
11128                         ret = btrfs_trim_block_group(cache,
11129                                                      &group_trimmed,
11130                                                      start,
11131                                                      end,
11132                                                      range->minlen);
11133
11134                         trimmed += group_trimmed;
11135                         if (ret) {
11136                                 btrfs_put_block_group(cache);
11137                                 break;
11138                         }
11139                 }
11140
11141                 cache = next_block_group(fs_info->tree_root, cache);
11142         }
11143
11144         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
11145         devices = &root->fs_info->fs_devices->alloc_list;
11146         list_for_each_entry(device, devices, dev_alloc_list) {
11147                 ret = btrfs_trim_free_extents(device, range->minlen,
11148                                               &group_trimmed);
11149                 if (ret)
11150                         break;
11151
11152                 trimmed += group_trimmed;
11153         }
11154         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
11155
11156         range->len = trimmed;
11157         return ret;
11158 }
11159
11160 /*
11161  * btrfs_{start,end}_write_no_snapshoting() are similar to
11162  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
11163  * data into the page cache through nocow before the subvolume is snapshoted,
11164  * but flush the data into disk after the snapshot creation, or to prevent
11165  * operations while snapshoting is ongoing and that cause the snapshot to be
11166  * inconsistent (writes followed by expanding truncates for example).
11167  */
11168 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
11169 {
11170         percpu_counter_dec(&root->subv_writers->counter);
11171         /*
11172          * Make sure counter is updated before we wake up waiters.
11173          */
11174         smp_mb();
11175         if (waitqueue_active(&root->subv_writers->wait))
11176                 wake_up(&root->subv_writers->wait);
11177 }
11178
11179 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
11180 {
11181         if (atomic_read(&root->will_be_snapshoted))
11182                 return 0;
11183
11184         percpu_counter_inc(&root->subv_writers->counter);
11185         /*
11186          * Make sure counter is updated before we check for snapshot creation.
11187          */
11188         smp_mb();
11189         if (atomic_read(&root->will_be_snapshoted)) {
11190                 btrfs_end_write_no_snapshoting(root);
11191                 return 0;
11192         }
11193         return 1;
11194 }
11195
11196 static int wait_snapshoting_atomic_t(atomic_t *a)
11197 {
11198         schedule();
11199         return 0;
11200 }
11201
11202 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11203 {
11204         while (true) {
11205                 int ret;
11206
11207                 ret = btrfs_start_write_no_snapshoting(root);
11208                 if (ret)
11209                         break;
11210                 wait_on_atomic_t(&root->will_be_snapshoted,
11211                                  wait_snapshoting_atomic_t,
11212                                  TASK_UNINTERRUPTIBLE);
11213         }
11214 }