fs/btrfs/free-space-cache.c

   1 /*
   2  * Copyright (C) 2008 Red Hat.  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
  19 #include <linux/pagemap.h>
  20 #include <linux/sched.h>
  21 #include <linux/slab.h>
  22 #include <linux/math64.h>
  23 #include <linux/ratelimit.h>
  24 #include "ctree.h"
  25 #include "free-space-cache.h"
  26 #include "transaction.h"
  27 #include "disk-io.h"
  28 #include "extent_io.h"
  29 #include "inode-map.h"
  30
  31 #define BITS_PER_BITMAP         (PAGE_CACHE_SIZE * 8)
  32 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
  33
  34 static int link_free_space(struct btrfs_free_space_ctl *ctl,
  35                            struct btrfs_free_space *info);
  36 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
  37                               struct btrfs_free_space *info);
  38
  39 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
  40                                                struct btrfs_path *path,
  41                                                u64 offset)
  42 {
  43         struct btrfs_key key;
  44         struct btrfs_key location;
  45         struct btrfs_disk_key disk_key;
  46         struct btrfs_free_space_header *header;
  47         struct extent_buffer *leaf;
  48         struct inode *inode = NULL;
  49         int ret;
  50
  51         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
  52         key.offset = offset;
  53         key.type = 0;
  54
  55         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  56         if (ret < 0)
  57                 return ERR_PTR(ret);
  58         if (ret > 0) {
  59                 btrfs_release_path(path);
  60                 return ERR_PTR(-ENOENT);
  61         }
  62
  63         leaf = path->nodes[0];
  64         header = btrfs_item_ptr(leaf, path->slots[0],
  65                                 struct btrfs_free_space_header);
  66         btrfs_free_space_key(leaf, header, &disk_key);
  67         btrfs_disk_key_to_cpu(&location, &disk_key);
  68         btrfs_release_path(path);
  69
  70         inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
  71         if (!inode)
  72                 return ERR_PTR(-ENOENT);
  73         if (IS_ERR(inode))
  74                 return inode;
  75         if (is_bad_inode(inode)) {
  76                 iput(inode);
  77                 return ERR_PTR(-ENOENT);
  78         }
  79
  80         mapping_set_gfp_mask(inode->i_mapping,
  81                         mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
  82
  83         return inode;
  84 }
  85
  86 struct inode *lookup_free_space_inode(struct btrfs_root *root,
  87                                       struct btrfs_block_group_cache
  88                                       *block_group, struct btrfs_path *path)
  89 {
  90         struct inode *inode = NULL;
  91         u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
  92
  93         spin_lock(&block_group->lock);
  94         if (block_group->inode)
  95                 inode = igrab(block_group->inode);
  96         spin_unlock(&block_group->lock);
  97         if (inode)
  98                 return inode;
  99
 100         inode = __lookup_free_space_inode(root, path,
 101                                           block_group->key.objectid);
 102         if (IS_ERR(inode))
 103                 return inode;
 104
 105         spin_lock(&block_group->lock);
 106         if (!((BTRFS_I(inode)->flags & flags) == flags)) {
 107                 btrfs_info(root->fs_info,
 108                         "Old style space inode found, converting.");
 109                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
 110                         BTRFS_INODE_NODATACOW;
 111                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 112         }
 113
 114         if (!block_group->iref) {
 115                 block_group->inode = igrab(inode);
 116                 block_group->iref = 1;
 117         }
 118         spin_unlock(&block_group->lock);
 119
 120         return inode;
 121 }
 122
 123 static int __create_free_space_inode(struct btrfs_root *root,
 124                                      struct btrfs_trans_handle *trans,
 125                                      struct btrfs_path *path,
 126                                      u64 ino, u64 offset)
 127 {
 128         struct btrfs_key key;
 129         struct btrfs_disk_key disk_key;
 130         struct btrfs_free_space_header *header;
 131         struct btrfs_inode_item *inode_item;
 132         struct extent_buffer *leaf;
 133         u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
 134         int ret;
 135
 136         ret = btrfs_insert_empty_inode(trans, root, path, ino);
 137         if (ret)
 138                 return ret;
 139
 140         /* We inline crc's for the free disk space cache */
 141         if (ino != BTRFS_FREE_INO_OBJECTID)
 142                 flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
 143
 144         leaf = path->nodes[0];
 145         inode_item = btrfs_item_ptr(leaf, path->slots[0],
 146                                     struct btrfs_inode_item);
 147         btrfs_item_key(leaf, &disk_key, path->slots[0]);
 148         memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
 149                              sizeof(*inode_item));
 150         btrfs_set_inode_generation(leaf, inode_item, trans->transid);
 151         btrfs_set_inode_size(leaf, inode_item, 0);
 152         btrfs_set_inode_nbytes(leaf, inode_item, 0);
 153         btrfs_set_inode_uid(leaf, inode_item, 0);
 154         btrfs_set_inode_gid(leaf, inode_item, 0);
 155         btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
 156         btrfs_set_inode_flags(leaf, inode_item, flags);
 157         btrfs_set_inode_nlink(leaf, inode_item, 1);
 158         btrfs_set_inode_transid(leaf, inode_item, trans->transid);
 159         btrfs_set_inode_block_group(leaf, inode_item, offset);
 160         btrfs_mark_buffer_dirty(leaf);
 161         btrfs_release_path(path);
 162
 163         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 164         key.offset = offset;
 165         key.type = 0;
 166
 167         ret = btrfs_insert_empty_item(trans, root, path, &key,
 168                                       sizeof(struct btrfs_free_space_header));
 169         if (ret < 0) {
 170                 btrfs_release_path(path);
 171                 return ret;
 172         }
 173         leaf = path->nodes[0];
 174         header = btrfs_item_ptr(leaf, path->slots[0],
 175                                 struct btrfs_free_space_header);
 176         memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
 177         btrfs_set_free_space_key(leaf, header, &disk_key);
 178         btrfs_mark_buffer_dirty(leaf);
 179         btrfs_release_path(path);
 180
 181         return 0;
 182 }
 183
 184 int create_free_space_inode(struct btrfs_root *root,
 185                             struct btrfs_trans_handle *trans,
 186                             struct btrfs_block_group_cache *block_group,
 187                             struct btrfs_path *path)
 188 {
 189         int ret;
 190         u64 ino;
 191
 192         ret = btrfs_find_free_objectid(root, &ino);
 193         if (ret < 0)
 194                 return ret;
 195
 196         return __create_free_space_inode(root, trans, path, ino,
 197                                          block_group->key.objectid);
 198 }
 199
 200 int btrfs_check_trunc_cache_free_space(struct btrfs_root *root,
 201                                        struct btrfs_block_rsv *rsv)
 202 {
 203         u64 needed_bytes;
 204         int ret;
 205
 206         /* 1 for slack space, 1 for updating the inode */
 207         needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
 208                 btrfs_calc_trans_metadata_size(root, 1);
 209
 210         spin_lock(&rsv->lock);
 211         if (rsv->reserved < needed_bytes)
 212                 ret = -ENOSPC;
 213         else
 214                 ret = 0;
 215         spin_unlock(&rsv->lock);
 216         return ret;
 217 }
 218
 219 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
 220                                     struct btrfs_trans_handle *trans,
 221                                     struct inode *inode)
 222 {
 223         int ret = 0;
 224
 225         btrfs_i_size_write(inode, 0);
 226         truncate_pagecache(inode, 0);
 227
 228         /*
 229          * We don't need an orphan item because truncating the free space cache
 230          * will never be split across transactions.
 231          */
 232         ret = btrfs_truncate_inode_items(trans, root, inode,
 233                                          0, BTRFS_EXTENT_DATA_KEY);
 234         if (ret) {
 235                 btrfs_abort_transaction(trans, root, ret);
 236                 return ret;
 237         }
 238
 239         ret = btrfs_update_inode(trans, root, inode);
 240         if (ret)
 241                 btrfs_abort_transaction(trans, root, ret);
 242
 243         return ret;
 244 }
 245
 246 static int readahead_cache(struct inode *inode)
 247 {
 248         struct file_ra_state *ra;
 249         unsigned long last_index;
 250
 251         ra = kzalloc(sizeof(*ra), GFP_NOFS);
 252         if (!ra)
 253                 return -ENOMEM;
 254
 255         file_ra_state_init(ra, inode->i_mapping);
 256         last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
 257
 258         page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
 259
 260         kfree(ra);
 261
 262         return 0;
 263 }
 264
 265 struct io_ctl {
 266         void *cur, *orig;
 267         struct page *page;
 268         struct page **pages;
 269         struct btrfs_root *root;
 270         unsigned long size;
 271         int index;
 272         int num_pages;
 273         unsigned check_crcs:1;
 274 };
 275
 276 static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
 277                        struct btrfs_root *root, int write)
 278 {
 279         int num_pages;
 280         int check_crcs = 0;
 281
 282         num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
 283                     PAGE_CACHE_SHIFT;
 284
 285         if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
 286                 check_crcs = 1;
 287
 288         /* Make sure we can fit our crcs into the first page */
 289         if (write && check_crcs &&
 290             (num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE)
 291                 return -ENOSPC;
 292
 293         memset(io_ctl, 0, sizeof(struct io_ctl));
 294
 295         io_ctl->pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS);
 296         if (!io_ctl->pages)
 297                 return -ENOMEM;
 298
 299         io_ctl->num_pages = num_pages;
 300         io_ctl->root = root;
 301         io_ctl->check_crcs = check_crcs;
 302
 303         return 0;
 304 }
 305
 306 static void io_ctl_free(struct io_ctl *io_ctl)
 307 {
 308         kfree(io_ctl->pages);
 309 }
 310
 311 static void io_ctl_unmap_page(struct io_ctl *io_ctl)
 312 {
 313         if (io_ctl->cur) {
 314                 kunmap(io_ctl->page);
 315                 io_ctl->cur = NULL;
 316                 io_ctl->orig = NULL;
 317         }
 318 }
 319
 320 static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
 321 {
 322         ASSERT(io_ctl->index < io_ctl->num_pages);
 323         io_ctl->page = io_ctl->pages[io_ctl->index++];
 324         io_ctl->cur = kmap(io_ctl->page);
 325         io_ctl->orig = io_ctl->cur;
 326         io_ctl->size = PAGE_CACHE_SIZE;
 327         if (clear)
 328                 memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
 329 }
 330
 331 static void io_ctl_drop_pages(struct io_ctl *io_ctl)
 332 {
 333         int i;
 334
 335         io_ctl_unmap_page(io_ctl);
 336
 337         for (i = 0; i < io_ctl->num_pages; i++) {
 338                 if (io_ctl->pages[i]) {
 339                         ClearPageChecked(io_ctl->pages[i]);
 340                         unlock_page(io_ctl->pages[i]);
 341                         page_cache_release(io_ctl->pages[i]);
 342                 }
 343         }
 344 }
 345
 346 static int io_ctl_prepare_pages(struct io_ctl *io_ctl, struct inode *inode,
 347                                 int uptodate)
 348 {
 349         struct page *page;
 350         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
 351         int i;
 352
 353         for (i = 0; i < io_ctl->num_pages; i++) {
 354                 page = find_or_create_page(inode->i_mapping, i, mask);
 355                 if (!page) {
 356                         io_ctl_drop_pages(io_ctl);
 357                         return -ENOMEM;
 358                 }
 359                 io_ctl->pages[i] = page;
 360                 if (uptodate && !PageUptodate(page)) {
 361                         btrfs_readpage(NULL, page);
 362                         lock_page(page);
 363                         if (!PageUptodate(page)) {
 364                                 btrfs_err(BTRFS_I(inode)->root->fs_info,
 365                                            "error reading free space cache");
 366                                 io_ctl_drop_pages(io_ctl);
 367                                 return -EIO;
 368                         }
 369                 }
 370         }
 371
 372         for (i = 0; i < io_ctl->num_pages; i++) {
 373                 clear_page_dirty_for_io(io_ctl->pages[i]);
 374                 set_page_extent_mapped(io_ctl->pages[i]);
 375         }
 376
 377         return 0;
 378 }
 379
 380 static void io_ctl_set_generation(struct io_ctl *io_ctl, u64 generation)
 381 {
 382         __le64 *val;
 383
 384         io_ctl_map_page(io_ctl, 1);
 385
 386         /*
 387          * Skip the csum areas.  If we don't check crcs then we just have a
 388          * 64bit chunk at the front of the first page.
 389          */
 390         if (io_ctl->check_crcs) {
 391                 io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
 392                 io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
 393         } else {
 394                 io_ctl->cur += sizeof(u64);
 395                 io_ctl->size -= sizeof(u64) * 2;
 396         }
 397
 398         val = io_ctl->cur;
 399         *val = cpu_to_le64(generation);
 400         io_ctl->cur += sizeof(u64);
 401 }
 402
 403 static int io_ctl_check_generation(struct io_ctl *io_ctl, u64 generation)
 404 {
 405         __le64 *gen;
 406
 407         /*
 408          * Skip the crc area.  If we don't check crcs then we just have a 64bit
 409          * chunk at the front of the first page.
 410          */
 411         if (io_ctl->check_crcs) {
 412                 io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
 413                 io_ctl->size -= sizeof(u64) +
 414                         (sizeof(u32) * io_ctl->num_pages);
 415         } else {
 416                 io_ctl->cur += sizeof(u64);
 417                 io_ctl->size -= sizeof(u64) * 2;
 418         }
 419
 420         gen = io_ctl->cur;
 421         if (le64_to_cpu(*gen) != generation) {
 422                 printk_ratelimited(KERN_ERR "BTRFS: space cache generation "
 423                                    "(%Lu) does not match inode (%Lu)\n", *gen,
 424                                    generation);
 425                 io_ctl_unmap_page(io_ctl);
 426                 return -EIO;
 427         }
 428         io_ctl->cur += sizeof(u64);
 429         return 0;
 430 }
 431
 432 static void io_ctl_set_crc(struct io_ctl *io_ctl, int index)
 433 {
 434         u32 *tmp;
 435         u32 crc = ~(u32)0;
 436         unsigned offset = 0;
 437
 438         if (!io_ctl->check_crcs) {
 439                 io_ctl_unmap_page(io_ctl);
 440                 return;
 441         }
 442
 443         if (index == 0)
 444                 offset = sizeof(u32) * io_ctl->num_pages;
 445
 446         crc = btrfs_csum_data(io_ctl->orig + offset, crc,
 447                               PAGE_CACHE_SIZE - offset);
 448         btrfs_csum_final(crc, (char *)&crc);
 449         io_ctl_unmap_page(io_ctl);
 450         tmp = kmap(io_ctl->pages[0]);
 451         tmp += index;
 452         *tmp = crc;
 453         kunmap(io_ctl->pages[0]);
 454 }
 455
 456 static int io_ctl_check_crc(struct io_ctl *io_ctl, int index)
 457 {
 458         u32 *tmp, val;
 459         u32 crc = ~(u32)0;
 460         unsigned offset = 0;
 461
 462         if (!io_ctl->check_crcs) {
 463                 io_ctl_map_page(io_ctl, 0);
 464                 return 0;
 465         }
 466
 467         if (index == 0)
 468                 offset = sizeof(u32) * io_ctl->num_pages;
 469
 470         tmp = kmap(io_ctl->pages[0]);
 471         tmp += index;
 472         val = *tmp;
 473         kunmap(io_ctl->pages[0]);
 474
 475         io_ctl_map_page(io_ctl, 0);
 476         crc = btrfs_csum_data(io_ctl->orig + offset, crc,
 477                               PAGE_CACHE_SIZE - offset);
 478         btrfs_csum_final(crc, (char *)&crc);
 479         if (val != crc) {
 480                 printk_ratelimited(KERN_ERR "BTRFS: csum mismatch on free "
 481                                    "space cache\n");
 482                 io_ctl_unmap_page(io_ctl);
 483                 return -EIO;
 484         }
 485
 486         return 0;
 487 }
 488
 489 static int io_ctl_add_entry(struct io_ctl *io_ctl, u64 offset, u64 bytes,
 490                             void *bitmap)
 491 {
 492         struct btrfs_free_space_entry *entry;
 493
 494         if (!io_ctl->cur)
 495                 return -ENOSPC;
 496
 497         entry = io_ctl->cur;
 498         entry->offset = cpu_to_le64(offset);
 499         entry->bytes = cpu_to_le64(bytes);
 500         entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
 501                 BTRFS_FREE_SPACE_EXTENT;
 502         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 503         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 504
 505         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 506                 return 0;
 507
 508         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 509
 510         /* No more pages to map */
 511         if (io_ctl->index >= io_ctl->num_pages)
 512                 return 0;
 513
 514         /* map the next page */
 515         io_ctl_map_page(io_ctl, 1);
 516         return 0;
 517 }
 518
 519 static int io_ctl_add_bitmap(struct io_ctl *io_ctl, void *bitmap)
 520 {
 521         if (!io_ctl->cur)
 522                 return -ENOSPC;
 523
 524         /*
 525          * If we aren't at the start of the current page, unmap this one and
 526          * map the next one if there is any left.
 527          */
 528         if (io_ctl->cur != io_ctl->orig) {
 529                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 530                 if (io_ctl->index >= io_ctl->num_pages)
 531                         return -ENOSPC;
 532                 io_ctl_map_page(io_ctl, 0);
 533         }
 534
 535         memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
 536         io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 537         if (io_ctl->index < io_ctl->num_pages)
 538                 io_ctl_map_page(io_ctl, 0);
 539         return 0;
 540 }
 541
 542 static void io_ctl_zero_remaining_pages(struct io_ctl *io_ctl)
 543 {
 544         /*
 545          * If we're not on the boundary we know we've modified the page and we
 546          * need to crc the page.
 547          */
 548         if (io_ctl->cur != io_ctl->orig)
 549                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 550         else
 551                 io_ctl_unmap_page(io_ctl);
 552
 553         while (io_ctl->index < io_ctl->num_pages) {
 554                 io_ctl_map_page(io_ctl, 1);
 555                 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
 556         }
 557 }
 558
 559 static int io_ctl_read_entry(struct io_ctl *io_ctl,
 560                             struct btrfs_free_space *entry, u8 *type)
 561 {
 562         struct btrfs_free_space_entry *e;
 563         int ret;
 564
 565         if (!io_ctl->cur) {
 566                 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 567                 if (ret)
 568                         return ret;
 569         }
 570
 571         e = io_ctl->cur;
 572         entry->offset = le64_to_cpu(e->offset);
 573         entry->bytes = le64_to_cpu(e->bytes);
 574         *type = e->type;
 575         io_ctl->cur += sizeof(struct btrfs_free_space_entry);
 576         io_ctl->size -= sizeof(struct btrfs_free_space_entry);
 577
 578         if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
 579                 return 0;
 580
 581         io_ctl_unmap_page(io_ctl);
 582
 583         return 0;
 584 }
 585
 586 static int io_ctl_read_bitmap(struct io_ctl *io_ctl,
 587                               struct btrfs_free_space *entry)
 588 {
 589         int ret;
 590
 591         ret = io_ctl_check_crc(io_ctl, io_ctl->index);
 592         if (ret)
 593                 return ret;
 594
 595         memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
 596         io_ctl_unmap_page(io_ctl);
 597
 598         return 0;
 599 }
 600
 601 /*
 602  * Since we attach pinned extents after the fact we can have contiguous sections
 603  * of free space that are split up in entries.  This poses a problem with the
 604  * tree logging stuff since it could have allocated across what appears to be 2
 605  * entries since we would have merged the entries when adding the pinned extents
 606  * back to the free space cache.  So run through the space cache that we just
 607  * loaded and merge contiguous entries.  This will make the log replay stuff not
 608  * blow up and it will make for nicer allocator behavior.
 609  */
 610 static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
 611 {
 612         struct btrfs_free_space *e, *prev = NULL;
 613         struct rb_node *n;
 614
 615 again:
 616         spin_lock(&ctl->tree_lock);
 617         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
 618                 e = rb_entry(n, struct btrfs_free_space, offset_index);
 619                 if (!prev)
 620                         goto next;
 621                 if (e->bitmap || prev->bitmap)
 622                         goto next;
 623                 if (prev->offset + prev->bytes == e->offset) {
 624                         unlink_free_space(ctl, prev);
 625                         unlink_free_space(ctl, e);
 626                         prev->bytes += e->bytes;
 627                         kmem_cache_free(btrfs_free_space_cachep, e);
 628                         link_free_space(ctl, prev);
 629                         prev = NULL;
 630                         spin_unlock(&ctl->tree_lock);
 631                         goto again;
 632                 }
 633 next:
 634                 prev = e;
 635         }
 636         spin_unlock(&ctl->tree_lock);
 637 }
 638
 639 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 640                                    struct btrfs_free_space_ctl *ctl,
 641                                    struct btrfs_path *path, u64 offset)
 642 {
 643         struct btrfs_free_space_header *header;
 644         struct extent_buffer *leaf;
 645         struct io_ctl io_ctl;
 646         struct btrfs_key key;
 647         struct btrfs_free_space *e, *n;
 648         struct list_head bitmaps;
 649         u64 num_entries;
 650         u64 num_bitmaps;
 651         u64 generation;
 652         u8 type;
 653         int ret = 0;
 654
 655         INIT_LIST_HEAD(&bitmaps);
 656
 657         /* Nothing in the space cache, goodbye */
 658         if (!i_size_read(inode))
 659                 return 0;
 660
 661         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 662         key.offset = offset;
 663         key.type = 0;
 664
 665         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 666         if (ret < 0)
 667                 return 0;
 668         else if (ret > 0) {
 669                 btrfs_release_path(path);
 670                 return 0;
 671         }
 672
 673         ret = -1;
 674
 675         leaf = path->nodes[0];
 676         header = btrfs_item_ptr(leaf, path->slots[0],
 677                                 struct btrfs_free_space_header);
 678         num_entries = btrfs_free_space_entries(leaf, header);
 679         num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
 680         generation = btrfs_free_space_generation(leaf, header);
 681         btrfs_release_path(path);
 682
 683         if (!BTRFS_I(inode)->generation) {
 684                 btrfs_info(root->fs_info,
 685                            "The free space cache file (%llu) is invalid. skip it\n",
 686                            offset);
 687                 return 0;
 688         }
 689
 690         if (BTRFS_I(inode)->generation != generation) {
 691                 btrfs_err(root->fs_info,
 692                         "free space inode generation (%llu) "
 693                         "did not match free space cache generation (%llu)",
 694                         BTRFS_I(inode)->generation, generation);
 695                 return 0;
 696         }
 697
 698         if (!num_entries)
 699                 return 0;
 700
 701         ret = io_ctl_init(&io_ctl, inode, root, 0);
 702         if (ret)
 703                 return ret;
 704
 705         ret = readahead_cache(inode);
 706         if (ret)
 707                 goto out;
 708
 709         ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
 710         if (ret)
 711                 goto out;
 712
 713         ret = io_ctl_check_crc(&io_ctl, 0);
 714         if (ret)
 715                 goto free_cache;
 716
 717         ret = io_ctl_check_generation(&io_ctl, generation);
 718         if (ret)
 719                 goto free_cache;
 720
 721         while (num_entries) {
 722                 e = kmem_cache_zalloc(btrfs_free_space_cachep,
 723                                       GFP_NOFS);
 724                 if (!e)
 725                         goto free_cache;
 726
 727                 ret = io_ctl_read_entry(&io_ctl, e, &type);
 728                 if (ret) {
 729                         kmem_cache_free(btrfs_free_space_cachep, e);
 730                         goto free_cache;
 731                 }
 732
 733                 if (!e->bytes) {
 734                         kmem_cache_free(btrfs_free_space_cachep, e);
 735                         goto free_cache;
 736                 }
 737
 738                 if (type == BTRFS_FREE_SPACE_EXTENT) {
 739                         spin_lock(&ctl->tree_lock);
 740                         ret = link_free_space(ctl, e);
 741                         spin_unlock(&ctl->tree_lock);
 742                         if (ret) {
 743                                 btrfs_err(root->fs_info,
 744                                         "Duplicate entries in free space cache, dumping");
 745                                 kmem_cache_free(btrfs_free_space_cachep, e);
 746                                 goto free_cache;
 747                         }
 748                 } else {
 749                         ASSERT(num_bitmaps);
 750                         num_bitmaps--;
 751                         e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
 752                         if (!e->bitmap) {
 753                                 kmem_cache_free(
 754                                         btrfs_free_space_cachep, e);
 755                                 goto free_cache;
 756                         }
 757                         spin_lock(&ctl->tree_lock);
 758                         ret = link_free_space(ctl, e);
 759                         ctl->total_bitmaps++;
 760                         ctl->op->recalc_thresholds(ctl);
 761                         spin_unlock(&ctl->tree_lock);
 762                         if (ret) {
 763                                 btrfs_err(root->fs_info,
 764                                         "Duplicate entries in free space cache, dumping");
 765                                 kmem_cache_free(btrfs_free_space_cachep, e);
 766                                 goto free_cache;
 767                         }
 768                         list_add_tail(&e->list, &bitmaps);
 769                 }
 770
 771                 num_entries--;
 772         }
 773
 774         io_ctl_unmap_page(&io_ctl);
 775
 776         /*
 777          * We add the bitmaps at the end of the entries in order that
 778          * the bitmap entries are added to the cache.
 779          */
 780         list_for_each_entry_safe(e, n, &bitmaps, list) {
 781                 list_del_init(&e->list);
 782                 ret = io_ctl_read_bitmap(&io_ctl, e);
 783                 if (ret)
 784                         goto free_cache;
 785         }
 786
 787         io_ctl_drop_pages(&io_ctl);
 788         merge_space_tree(ctl);
 789         ret = 1;
 790 out:
 791         io_ctl_free(&io_ctl);
 792         return ret;
 793 free_cache:
 794         io_ctl_drop_pages(&io_ctl);
 795         __btrfs_remove_free_space_cache(ctl);
 796         goto out;
 797 }
 798
 799 int load_free_space_cache(struct btrfs_fs_info *fs_info,
 800                           struct btrfs_block_group_cache *block_group)
 801 {
 802         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 803         struct btrfs_root *root = fs_info->tree_root;
 804         struct inode *inode;
 805         struct btrfs_path *path;
 806         int ret = 0;
 807         bool matched;
 808         u64 used = btrfs_block_group_used(&block_group->item);
 809
 810         /*
 811          * If this block group has been marked to be cleared for one reason or
 812          * another then we can't trust the on disk cache, so just return.
 813          */
 814         spin_lock(&block_group->lock);
 815         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 816                 spin_unlock(&block_group->lock);
 817                 return 0;
 818         }
 819         spin_unlock(&block_group->lock);
 820
 821         path = btrfs_alloc_path();
 822         if (!path)
 823                 return 0;
 824         path->search_commit_root = 1;
 825         path->skip_locking = 1;
 826
 827         inode = lookup_free_space_inode(root, block_group, path);
 828         if (IS_ERR(inode)) {
 829                 btrfs_free_path(path);
 830                 return 0;
 831         }
 832
 833         /* We may have converted the inode and made the cache invalid. */
 834         spin_lock(&block_group->lock);
 835         if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
 836                 spin_unlock(&block_group->lock);
 837                 btrfs_free_path(path);
 838                 goto out;
 839         }
 840         spin_unlock(&block_group->lock);
 841
 842         ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
 843                                       path, block_group->key.objectid);
 844         btrfs_free_path(path);
 845         if (ret <= 0)
 846                 goto out;
 847
 848         spin_lock(&ctl->tree_lock);
 849         matched = (ctl->free_space == (block_group->key.offset - used -
 850                                        block_group->bytes_super));
 851         spin_unlock(&ctl->tree_lock);
 852
 853         if (!matched) {
 854                 __btrfs_remove_free_space_cache(ctl);
 855                 btrfs_warn(fs_info, "block group %llu has wrong amount of free space",
 856                         block_group->key.objectid);
 857                 ret = -1;
 858         }
 859 out:
 860         if (ret < 0) {
 861                 /* This cache is bogus, make sure it gets cleared */
 862                 spin_lock(&block_group->lock);
 863                 block_group->disk_cache_state = BTRFS_DC_CLEAR;
 864                 spin_unlock(&block_group->lock);
 865                 ret = 0;
 866
 867                 btrfs_warn(fs_info, "failed to load free space cache for block group %llu, rebuild it now",
 868                         block_group->key.objectid);
 869         }
 870
 871         iput(inode);
 872         return ret;
 873 }
 874
 875 static noinline_for_stack
 876 int write_cache_extent_entries(struct io_ctl *io_ctl,
 877                               struct btrfs_free_space_ctl *ctl,
 878                               struct btrfs_block_group_cache *block_group,
 879                               int *entries, int *bitmaps,
 880                               struct list_head *bitmap_list)
 881 {
 882         int ret;
 883         struct btrfs_free_cluster *cluster = NULL;
 884         struct rb_node *node = rb_first(&ctl->free_space_offset);
 885
 886         /* Get the cluster for this block_group if it exists */
 887         if (block_group && !list_empty(&block_group->cluster_list)) {
 888                 cluster = list_entry(block_group->cluster_list.next,
 889                                      struct btrfs_free_cluster,
 890                                      block_group_list);
 891         }
 892
 893         if (!node && cluster) {
 894                 node = rb_first(&cluster->root);
 895                 cluster = NULL;
 896         }
 897
 898         /* Write out the extent entries */
 899         while (node) {
 900                 struct btrfs_free_space *e;
 901
 902                 e = rb_entry(node, struct btrfs_free_space, offset_index);
 903                 *entries += 1;
 904
 905                 ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
 906                                        e->bitmap);
 907                 if (ret)
 908                         goto fail;
 909
 910                 if (e->bitmap) {
 911                         list_add_tail(&e->list, bitmap_list);
 912                         *bitmaps += 1;
 913                 }
 914                 node = rb_next(node);
 915                 if (!node && cluster) {
 916                         node = rb_first(&cluster->root);
 917                         cluster = NULL;
 918                 }
 919         }
 920         return 0;
 921 fail:
 922         return -ENOSPC;
 923 }
 924
 925 static noinline_for_stack int
 926 update_cache_item(struct btrfs_trans_handle *trans,
 927                   struct btrfs_root *root,
 928                   struct inode *inode,
 929                   struct btrfs_path *path, u64 offset,
 930                   int entries, int bitmaps)
 931 {
 932         struct btrfs_key key;
 933         struct btrfs_free_space_header *header;
 934         struct extent_buffer *leaf;
 935         int ret;
 936
 937         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 938         key.offset = offset;
 939         key.type = 0;
 940
 941         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
 942         if (ret < 0) {
 943                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
 944                                  EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
 945                                  GFP_NOFS);
 946                 goto fail;
 947         }
 948         leaf = path->nodes[0];
 949         if (ret > 0) {
 950                 struct btrfs_key found_key;
 951                 ASSERT(path->slots[0]);
 952                 path->slots[0]--;
 953                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 954                 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
 955                     found_key.offset != offset) {
 956                         clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
 957                                          inode->i_size - 1,
 958                                          EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
 959                                          NULL, GFP_NOFS);
 960                         btrfs_release_path(path);
 961                         goto fail;
 962                 }
 963         }
 964
 965         BTRFS_I(inode)->generation = trans->transid;
 966         header = btrfs_item_ptr(leaf, path->slots[0],
 967                                 struct btrfs_free_space_header);
 968         btrfs_set_free_space_entries(leaf, header, entries);
 969         btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
 970         btrfs_set_free_space_generation(leaf, header, trans->transid);
 971         btrfs_mark_buffer_dirty(leaf);
 972         btrfs_release_path(path);
 973
 974         return 0;
 975
 976 fail:
 977         return -1;
 978 }
 979
 980 static noinline_for_stack int
 981 write_pinned_extent_entries(struct btrfs_root *root,
 982                             struct btrfs_block_group_cache *block_group,
 983                             struct io_ctl *io_ctl,
 984                             int *entries)
 985 {
 986         u64 start, extent_start, extent_end, len;
 987         struct extent_io_tree *unpin = NULL;
 988         int ret;
 989
 990         if (!block_group)
 991                 return 0;
 992
 993         /*
 994          * We want to add any pinned extents to our free space cache
 995          * so we don't leak the space
 996          *
 997          * We shouldn't have switched the pinned extents yet so this is the
 998          * right one
 999          */
1000         unpin = root->fs_info->pinned_extents;
1001
1002         start = block_group->key.objectid;
1003
1004         while (start < block_group->key.objectid + block_group->key.offset) {
1005                 ret = find_first_extent_bit(unpin, start,
1006                                             &extent_start, &extent_end,
1007                                             EXTENT_DIRTY, NULL);
1008                 if (ret)
1009                         return 0;
1010
1011                 /* This pinned extent is out of our range */
1012                 if (extent_start >= block_group->key.objectid +
1013                     block_group->key.offset)
1014                         return 0;
1015
1016                 extent_start = max(extent_start, start);
1017                 extent_end = min(block_group->key.objectid +
1018                                  block_group->key.offset, extent_end + 1);
1019                 len = extent_end - extent_start;
1020
1021                 *entries += 1;
1022                 ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1023                 if (ret)
1024                         return -ENOSPC;
1025
1026                 start = extent_end;
1027         }
1028
1029         return 0;
1030 }
1031
1032 static noinline_for_stack int
1033 write_bitmap_entries(struct io_ctl *io_ctl, struct list_head *bitmap_list)
1034 {
1035         struct list_head *pos, *n;
1036         int ret;
1037
1038         /* Write out the bitmaps */
1039         list_for_each_safe(pos, n, bitmap_list) {
1040                 struct btrfs_free_space *entry =
1041                         list_entry(pos, struct btrfs_free_space, list);
1042
1043                 ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1044                 if (ret)
1045                         return -ENOSPC;
1046                 list_del_init(&entry->list);
1047         }
1048
1049         return 0;
1050 }
1051
1052 static int flush_dirty_cache(struct inode *inode)
1053 {
1054         int ret;
1055
1056         ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1057         if (ret)
1058                 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1059                                  EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1060                                  GFP_NOFS);
1061
1062         return ret;
1063 }
1064
1065 static void noinline_for_stack
1066 cleanup_write_cache_enospc(struct inode *inode,
1067                            struct io_ctl *io_ctl,
1068                            struct extent_state **cached_state,
1069                            struct list_head *bitmap_list)
1070 {
1071         struct list_head *pos, *n;
1072
1073         list_for_each_safe(pos, n, bitmap_list) {
1074                 struct btrfs_free_space *entry =
1075                         list_entry(pos, struct btrfs_free_space, list);
1076                 list_del_init(&entry->list);
1077         }
1078         io_ctl_drop_pages(io_ctl);
1079         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1080                              i_size_read(inode) - 1, cached_state,
1081                              GFP_NOFS);
1082 }
1083
1084 /**
1085  * __btrfs_write_out_cache - write out cached info to an inode
1086  * @root - the root the inode belongs to
1087  * @ctl - the free space cache we are going to write out
1088  * @block_group - the block_group for this cache if it belongs to a block_group
1089  * @trans - the trans handle
1090  * @path - the path to use
1091  * @offset - the offset for the key we'll insert
1092  *
1093  * This function writes out a free space cache struct to disk for quick recovery
1094  * on mount.  This will return 0 if it was successfull in writing the cache out,
1095  * and -1 if it was not.
1096  */
1097 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
1098                                    struct btrfs_free_space_ctl *ctl,
1099                                    struct btrfs_block_group_cache *block_group,
1100                                    struct btrfs_trans_handle *trans,
1101                                    struct btrfs_path *path, u64 offset)
1102 {
1103         struct extent_state *cached_state = NULL;
1104         struct io_ctl io_ctl;
1105         LIST_HEAD(bitmap_list);
1106         int entries = 0;
1107         int bitmaps = 0;
1108         int ret;
1109
1110         if (!i_size_read(inode))
1111                 return -1;
1112
1113         ret = io_ctl_init(&io_ctl, inode, root, 1);
1114         if (ret)
1115                 return -1;
1116
1117         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1118                 down_write(&block_group->data_rwsem);
1119                 spin_lock(&block_group->lock);
1120                 if (block_group->delalloc_bytes) {
1121                         block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1122                         spin_unlock(&block_group->lock);
1123                         up_write(&block_group->data_rwsem);
1124                         BTRFS_I(inode)->generation = 0;
1125                         ret = 0;
1126                         goto out;
1127                 }
1128                 spin_unlock(&block_group->lock);
1129         }
1130
1131         /* Lock all pages first so we can lock the extent safely. */
1132         io_ctl_prepare_pages(&io_ctl, inode, 0);
1133
1134         lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1135                          0, &cached_state);
1136
1137         io_ctl_set_generation(&io_ctl, trans->transid);
1138
1139         /* Write out the extent entries in the free space cache */
1140         ret = write_cache_extent_entries(&io_ctl, ctl,
1141                                          block_group, &entries, &bitmaps,
1142                                          &bitmap_list);
1143         if (ret)
1144                 goto out_nospc;
1145
1146         /*
1147          * Some spaces that are freed in the current transaction are pinned,
1148          * they will be added into free space cache after the transaction is
1149          * committed, we shouldn't lose them.
1150          */
1151         ret = write_pinned_extent_entries(root, block_group, &io_ctl, &entries);
1152         if (ret)
1153                 goto out_nospc;
1154
1155         /* At last, we write out all the bitmaps. */
1156         ret = write_bitmap_entries(&io_ctl, &bitmap_list);
1157         if (ret)
1158                 goto out_nospc;
1159
1160         /* Zero out the rest of the pages just to make sure */
1161         io_ctl_zero_remaining_pages(&io_ctl);
1162
1163         /* Everything is written out, now we dirty the pages in the file. */
1164         ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
1165                                 0, i_size_read(inode), &cached_state);
1166         if (ret)
1167                 goto out_nospc;
1168
1169         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1170                 up_write(&block_group->data_rwsem);
1171         /*
1172          * Release the pages and unlock the extent, we will flush
1173          * them out later
1174          */
1175         io_ctl_drop_pages(&io_ctl);
1176
1177         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1178                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1179
1180         /* Flush the dirty pages in the cache file. */
1181         ret = flush_dirty_cache(inode);
1182         if (ret)
1183                 goto out;
1184
1185         /* Update the cache item to tell everyone this cache file is valid. */
1186         ret = update_cache_item(trans, root, inode, path, offset,
1187                                 entries, bitmaps);
1188 out:
1189         io_ctl_free(&io_ctl);
1190         if (ret) {
1191                 invalidate_inode_pages2(inode->i_mapping);
1192                 BTRFS_I(inode)->generation = 0;
1193         }
1194         btrfs_update_inode(trans, root, inode);
1195         return ret;
1196
1197 out_nospc:
1198         cleanup_write_cache_enospc(inode, &io_ctl, &cached_state, &bitmap_list);
1199
1200         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1201                 up_write(&block_group->data_rwsem);
1202
1203         goto out;
1204 }
1205
1206 int btrfs_write_out_cache(struct btrfs_root *root,
1207                           struct btrfs_trans_handle *trans,
1208                           struct btrfs_block_group_cache *block_group,
1209                           struct btrfs_path *path)
1210 {
1211         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1212         struct inode *inode;
1213         int ret = 0;
1214
1215         root = root->fs_info->tree_root;
1216
1217         spin_lock(&block_group->lock);
1218         if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1219                 spin_unlock(&block_group->lock);
1220                 return 0;
1221         }
1222
1223         if (block_group->delalloc_bytes) {
1224                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1225                 spin_unlock(&block_group->lock);
1226                 return 0;
1227         }
1228         spin_unlock(&block_group->lock);
1229
1230         inode = lookup_free_space_inode(root, block_group, path);
1231         if (IS_ERR(inode))
1232                 return 0;
1233
1234         ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
1235                                       path, block_group->key.objectid);
1236         if (ret) {
1237                 spin_lock(&block_group->lock);
1238                 block_group->disk_cache_state = BTRFS_DC_ERROR;
1239                 spin_unlock(&block_group->lock);
1240                 ret = 0;
1241 #ifdef DEBUG
1242                 btrfs_err(root->fs_info,
1243                         "failed to write free space cache for block group %llu",
1244                         block_group->key.objectid);
1245 #endif
1246         }
1247
1248         iput(inode);
1249         return ret;
1250 }
1251
1252 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1253                                           u64 offset)
1254 {
1255         ASSERT(offset >= bitmap_start);
1256         offset -= bitmap_start;
1257         return (unsigned long)(div_u64(offset, unit));
1258 }
1259
1260 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1261 {
1262         return (unsigned long)(div_u64(bytes, unit));
1263 }
1264
1265 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1266                                    u64 offset)
1267 {
1268         u64 bitmap_start;
1269         u64 bytes_per_bitmap;
1270
1271         bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1272         bitmap_start = offset - ctl->start;
1273         bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1274         bitmap_start *= bytes_per_bitmap;
1275         bitmap_start += ctl->start;
1276
1277         return bitmap_start;
1278 }
1279
1280 static int tree_insert_offset(struct rb_root *root, u64 offset,
1281                               struct rb_node *node, int bitmap)
1282 {
1283         struct rb_node **p = &root->rb_node;
1284         struct rb_node *parent = NULL;
1285         struct btrfs_free_space *info;
1286
1287         while (*p) {
1288                 parent = *p;
1289                 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1290
1291                 if (offset < info->offset) {
1292                         p = &(*p)->rb_left;
1293                 } else if (offset > info->offset) {
1294                         p = &(*p)->rb_right;
1295                 } else {
1296                         /*
1297                          * we could have a bitmap entry and an extent entry
1298                          * share the same offset.  If this is the case, we want
1299                          * the extent entry to always be found first if we do a
1300                          * linear search through the tree, since we want to have
1301                          * the quickest allocation time, and allocating from an
1302                          * extent is faster than allocating from a bitmap.  So
1303                          * if we're inserting a bitmap and we find an entry at
1304                          * this offset, we want to go right, or after this entry
1305                          * logically.  If we are inserting an extent and we've
1306                          * found a bitmap, we want to go left, or before
1307                          * logically.
1308                          */
1309                         if (bitmap) {
1310                                 if (info->bitmap) {
1311                                         WARN_ON_ONCE(1);
1312                                         return -EEXIST;
1313                                 }
1314                                 p = &(*p)->rb_right;
1315                         } else {
1316                                 if (!info->bitmap) {
1317                                         WARN_ON_ONCE(1);
1318                                         return -EEXIST;
1319                                 }
1320                                 p = &(*p)->rb_left;
1321                         }
1322                 }
1323         }
1324
1325         rb_link_node(node, parent, p);
1326         rb_insert_color(node, root);
1327
1328         return 0;
1329 }
1330
1331 /*
1332  * searches the tree for the given offset.
1333  *
1334  * fuzzy - If this is set, then we are trying to make an allocation, and we just
1335  * want a section that has at least bytes size and comes at or after the given
1336  * offset.
1337  */
1338 static struct btrfs_free_space *
1339 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1340                    u64 offset, int bitmap_only, int fuzzy)
1341 {
1342         struct rb_node *n = ctl->free_space_offset.rb_node;
1343         struct btrfs_free_space *entry, *prev = NULL;
1344
1345         /* find entry that is closest to the 'offset' */
1346         while (1) {
1347                 if (!n) {
1348                         entry = NULL;
1349                         break;
1350                 }
1351
1352                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1353                 prev = entry;
1354
1355                 if (offset < entry->offset)
1356                         n = n->rb_left;
1357                 else if (offset > entry->offset)
1358                         n = n->rb_right;
1359                 else
1360                         break;
1361         }
1362
1363         if (bitmap_only) {
1364                 if (!entry)
1365                         return NULL;
1366                 if (entry->bitmap)
1367                         return entry;
1368
1369                 /*
1370                  * bitmap entry and extent entry may share same offset,
1371                  * in that case, bitmap entry comes after extent entry.
1372                  */
1373                 n = rb_next(n);
1374                 if (!n)
1375                         return NULL;
1376                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1377                 if (entry->offset != offset)
1378                         return NULL;
1379
1380                 WARN_ON(!entry->bitmap);
1381                 return entry;
1382         } else if (entry) {
1383                 if (entry->bitmap) {
1384                         /*
1385                          * if previous extent entry covers the offset,
1386                          * we should return it instead of the bitmap entry
1387                          */
1388                         n = rb_prev(&entry->offset_index);
1389                         if (n) {
1390                                 prev = rb_entry(n, struct btrfs_free_space,
1391                                                 offset_index);
1392                                 if (!prev->bitmap &&
1393                                     prev->offset + prev->bytes > offset)
1394                                         entry = prev;
1395                         }
1396                 }
1397                 return entry;
1398         }
1399
1400         if (!prev)
1401                 return NULL;
1402
1403         /* find last entry before the 'offset' */
1404         entry = prev;
1405         if (entry->offset > offset) {
1406                 n = rb_prev(&entry->offset_index);
1407                 if (n) {
1408                         entry = rb_entry(n, struct btrfs_free_space,
1409                                         offset_index);
1410                         ASSERT(entry->offset <= offset);
1411                 } else {
1412                         if (fuzzy)
1413                                 return entry;
1414                         else
1415                                 return NULL;
1416                 }
1417         }
1418
1419         if (entry->bitmap) {
1420                 n = rb_prev(&entry->offset_index);
1421                 if (n) {
1422                         prev = rb_entry(n, struct btrfs_free_space,
1423                                         offset_index);
1424                         if (!prev->bitmap &&
1425                             prev->offset + prev->bytes > offset)
1426                                 return prev;
1427                 }
1428                 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1429                         return entry;
1430         } else if (entry->offset + entry->bytes > offset)
1431                 return entry;
1432
1433         if (!fuzzy)
1434                 return NULL;
1435
1436         while (1) {
1437                 if (entry->bitmap) {
1438                         if (entry->offset + BITS_PER_BITMAP *
1439                             ctl->unit > offset)
1440                                 break;
1441                 } else {
1442                         if (entry->offset + entry->bytes > offset)
1443                                 break;
1444                 }
1445
1446                 n = rb_next(&entry->offset_index);
1447                 if (!n)
1448                         return NULL;
1449                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1450         }
1451         return entry;
1452 }
1453
1454 static inline void
1455 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1456                     struct btrfs_free_space *info)
1457 {
1458         rb_erase(&info->offset_index, &ctl->free_space_offset);
1459         ctl->free_extents--;
1460 }
1461
1462 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1463                               struct btrfs_free_space *info)
1464 {
1465         __unlink_free_space(ctl, info);
1466         ctl->free_space -= info->bytes;
1467 }
1468
1469 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1470                            struct btrfs_free_space *info)
1471 {
1472         int ret = 0;
1473
1474         ASSERT(info->bytes || info->bitmap);
1475         ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1476                                  &info->offset_index, (info->bitmap != NULL));
1477         if (ret)
1478                 return ret;
1479
1480         ctl->free_space += info->bytes;
1481         ctl->free_extents++;
1482         return ret;
1483 }
1484
1485 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1486 {
1487         struct btrfs_block_group_cache *block_group = ctl->private;
1488         u64 max_bytes;
1489         u64 bitmap_bytes;
1490         u64 extent_bytes;
1491         u64 size = block_group->key.offset;
1492         u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1493         int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1494
1495         max_bitmaps = max(max_bitmaps, 1);
1496
1497         ASSERT(ctl->total_bitmaps <= max_bitmaps);
1498
1499         /*
1500          * The goal is to keep the total amount of memory used per 1gb of space
1501          * at or below 32k, so we need to adjust how much memory we allow to be
1502          * used by extent based free space tracking
1503          */
1504         if (size < 1024 * 1024 * 1024)
1505                 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1506         else
1507                 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1508                         div64_u64(size, 1024 * 1024 * 1024);
1509
1510         /*
1511          * we want to account for 1 more bitmap than what we have so we can make
1512          * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1513          * we add more bitmaps.
1514          */
1515         bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1516
1517         if (bitmap_bytes >= max_bytes) {
1518                 ctl->extents_thresh = 0;
1519                 return;
1520         }
1521
1522         /*
1523          * we want the extent entry threshold to always be at most 1/2 the maxw
1524          * bytes we can have, or whatever is less than that.
1525          */
1526         extent_bytes = max_bytes - bitmap_bytes;
1527         extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1528
1529         ctl->extents_thresh =
1530                 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1531 }
1532
1533 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1534                                        struct btrfs_free_space *info,
1535                                        u64 offset, u64 bytes)
1536 {
1537         unsigned long start, count;
1538
1539         start = offset_to_bit(info->offset, ctl->unit, offset);
1540         count = bytes_to_bits(bytes, ctl->unit);
1541         ASSERT(start + count <= BITS_PER_BITMAP);
1542
1543         bitmap_clear(info->bitmap, start, count);
1544
1545         info->bytes -= bytes;
1546 }
1547
1548 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1549                               struct btrfs_free_space *info, u64 offset,
1550                               u64 bytes)
1551 {
1552         __bitmap_clear_bits(ctl, info, offset, bytes);
1553         ctl->free_space -= bytes;
1554 }
1555
1556 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1557                             struct btrfs_free_space *info, u64 offset,
1558                             u64 bytes)
1559 {
1560         unsigned long start, count;
1561
1562         start = offset_to_bit(info->offset, ctl->unit, offset);
1563         count = bytes_to_bits(bytes, ctl->unit);
1564         ASSERT(start + count <= BITS_PER_BITMAP);
1565
1566         bitmap_set(info->bitmap, start, count);
1567
1568         info->bytes += bytes;
1569         ctl->free_space += bytes;
1570 }
1571
1572 /*
1573  * If we can not find suitable extent, we will use bytes to record
1574  * the size of the max extent.
1575  */
1576 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1577                          struct btrfs_free_space *bitmap_info, u64 *offset,
1578                          u64 *bytes)
1579 {
1580         unsigned long found_bits = 0;
1581         unsigned long max_bits = 0;
1582         unsigned long bits, i;
1583         unsigned long next_zero;
1584         unsigned long extent_bits;
1585
1586         i = offset_to_bit(bitmap_info->offset, ctl->unit,
1587                           max_t(u64, *offset, bitmap_info->offset));
1588         bits = bytes_to_bits(*bytes, ctl->unit);
1589
1590         for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1591                 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1592                                                BITS_PER_BITMAP, i);
1593                 extent_bits = next_zero - i;
1594                 if (extent_bits >= bits) {
1595                         found_bits = extent_bits;
1596                         break;
1597                 } else if (extent_bits > max_bits) {
1598                         max_bits = extent_bits;
1599                 }
1600                 i = next_zero;
1601         }
1602
1603         if (found_bits) {
1604                 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1605                 *bytes = (u64)(found_bits) * ctl->unit;
1606                 return 0;
1607         }
1608
1609         *bytes = (u64)(max_bits) * ctl->unit;
1610         return -1;
1611 }
1612
1613 /* Cache the size of the max extent in bytes */
1614 static struct btrfs_free_space *
1615 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1616                 unsigned long align, u64 *max_extent_size)
1617 {
1618         struct btrfs_free_space *entry;
1619         struct rb_node *node;
1620         u64 tmp;
1621         u64 align_off;
1622         int ret;
1623
1624         if (!ctl->free_space_offset.rb_node)
1625                 goto out;
1626
1627         entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1628         if (!entry)
1629                 goto out;
1630
1631         for (node = &entry->offset_index; node; node = rb_next(node)) {
1632                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1633                 if (entry->bytes < *bytes) {
1634                         if (entry->bytes > *max_extent_size)
1635                                 *max_extent_size = entry->bytes;
1636                         continue;
1637                 }
1638
1639                 /* make sure the space returned is big enough
1640                  * to match our requested alignment
1641                  */
1642                 if (*bytes >= align) {
1643                         tmp = entry->offset - ctl->start + align - 1;
1644                         do_div(tmp, align);
1645                         tmp = tmp * align + ctl->start;
1646                         align_off = tmp - entry->offset;
1647                 } else {
1648                         align_off = 0;
1649                         tmp = entry->offset;
1650                 }
1651
1652                 if (entry->bytes < *bytes + align_off) {
1653                         if (entry->bytes > *max_extent_size)
1654                                 *max_extent_size = entry->bytes;
1655                         continue;
1656                 }
1657
1658                 if (entry->bitmap) {
1659                         u64 size = *bytes;
1660
1661                         ret = search_bitmap(ctl, entry, &tmp, &size);
1662                         if (!ret) {
1663                                 *offset = tmp;
1664                                 *bytes = size;
1665                                 return entry;
1666                         } else if (size > *max_extent_size) {
1667                                 *max_extent_size = size;
1668                         }
1669                         continue;
1670                 }
1671
1672                 *offset = tmp;
1673                 *bytes = entry->bytes - align_off;
1674                 return entry;
1675         }
1676 out:
1677         return NULL;
1678 }
1679
1680 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1681                            struct btrfs_free_space *info, u64 offset)
1682 {
1683         info->offset = offset_to_bitmap(ctl, offset);
1684         info->bytes = 0;
1685         INIT_LIST_HEAD(&info->list);
1686         link_free_space(ctl, info);
1687         ctl->total_bitmaps++;
1688
1689         ctl->op->recalc_thresholds(ctl);
1690 }
1691
1692 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1693                         struct btrfs_free_space *bitmap_info)
1694 {
1695         unlink_free_space(ctl, bitmap_info);
1696         kfree(bitmap_info->bitmap);
1697         kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1698         ctl->total_bitmaps--;
1699         ctl->op->recalc_thresholds(ctl);
1700 }
1701
1702 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1703                               struct btrfs_free_space *bitmap_info,
1704                               u64 *offset, u64 *bytes)
1705 {
1706         u64 end;
1707         u64 search_start, search_bytes;
1708         int ret;
1709
1710 again:
1711         end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1712
1713         /*
1714          * We need to search for bits in this bitmap.  We could only cover some
1715          * of the extent in this bitmap thanks to how we add space, so we need
1716          * to search for as much as it as we can and clear that amount, and then
1717          * go searching for the next bit.
1718          */
1719         search_start = *offset;
1720         search_bytes = ctl->unit;
1721         search_bytes = min(search_bytes, end - search_start + 1);
1722         ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1723         if (ret < 0 || search_start != *offset)
1724                 return -EINVAL;
1725
1726         /* We may have found more bits than what we need */
1727         search_bytes = min(search_bytes, *bytes);
1728
1729         /* Cannot clear past the end of the bitmap */
1730         search_bytes = min(search_bytes, end - search_start + 1);
1731
1732         bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1733         *offset += search_bytes;
1734         *bytes -= search_bytes;
1735
1736         if (*bytes) {
1737                 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1738                 if (!bitmap_info->bytes)
1739                         free_bitmap(ctl, bitmap_info);
1740
1741                 /*
1742                  * no entry after this bitmap, but we still have bytes to
1743                  * remove, so something has gone wrong.
1744                  */
1745                 if (!next)
1746                         return -EINVAL;
1747
1748                 bitmap_info = rb_entry(next, struct btrfs_free_space,
1749                                        offset_index);
1750
1751                 /*
1752                  * if the next entry isn't a bitmap we need to return to let the
1753                  * extent stuff do its work.
1754                  */
1755                 if (!bitmap_info->bitmap)
1756                         return -EAGAIN;
1757
1758                 /*
1759                  * Ok the next item is a bitmap, but it may not actually hold
1760                  * the information for the rest of this free space stuff, so
1761                  * look for it, and if we don't find it return so we can try
1762                  * everything over again.
1763                  */
1764                 search_start = *offset;
1765                 search_bytes = ctl->unit;
1766                 ret = search_bitmap(ctl, bitmap_info, &search_start,
1767                                     &search_bytes);
1768                 if (ret < 0 || search_start != *offset)
1769                         return -EAGAIN;
1770
1771                 goto again;
1772         } else if (!bitmap_info->bytes)
1773                 free_bitmap(ctl, bitmap_info);
1774
1775         return 0;
1776 }
1777
1778 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1779                                struct btrfs_free_space *info, u64 offset,
1780                                u64 bytes)
1781 {
1782         u64 bytes_to_set = 0;
1783         u64 end;
1784
1785         end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1786
1787         bytes_to_set = min(end - offset, bytes);
1788
1789         bitmap_set_bits(ctl, info, offset, bytes_to_set);
1790
1791         return bytes_to_set;
1792
1793 }
1794
1795 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1796                       struct btrfs_free_space *info)
1797 {
1798         struct btrfs_block_group_cache *block_group = ctl->private;
1799
1800         /*
1801          * If we are below the extents threshold then we can add this as an
1802          * extent, and don't have to deal with the bitmap
1803          */
1804         if (ctl->free_extents < ctl->extents_thresh) {
1805                 /*
1806                  * If this block group has some small extents we don't want to
1807                  * use up all of our free slots in the cache with them, we want
1808                  * to reserve them to larger extents, however if we have plent
1809                  * of cache left then go ahead an dadd them, no sense in adding
1810                  * the overhead of a bitmap if we don't have to.
1811                  */
1812                 if (info->bytes <= block_group->sectorsize * 4) {
1813                         if (ctl->free_extents * 2 <= ctl->extents_thresh)
1814                                 return false;
1815                 } else {
1816                         return false;
1817                 }
1818         }
1819
1820         /*
1821          * The original block groups from mkfs can be really small, like 8
1822          * megabytes, so don't bother with a bitmap for those entries.  However
1823          * some block groups can be smaller than what a bitmap would cover but
1824          * are still large enough that they could overflow the 32k memory limit,
1825          * so allow those block groups to still be allowed to have a bitmap
1826          * entry.
1827          */
1828         if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
1829                 return false;
1830
1831         return true;
1832 }
1833
1834 static struct btrfs_free_space_op free_space_op = {
1835         .recalc_thresholds      = recalculate_thresholds,
1836         .use_bitmap             = use_bitmap,
1837 };
1838
1839 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1840                               struct btrfs_free_space *info)
1841 {
1842         struct btrfs_free_space *bitmap_info;
1843         struct btrfs_block_group_cache *block_group = NULL;
1844         int added = 0;
1845         u64 bytes, offset, bytes_added;
1846         int ret;
1847
1848         bytes = info->bytes;
1849         offset = info->offset;
1850
1851         if (!ctl->op->use_bitmap(ctl, info))
1852                 return 0;
1853
1854         if (ctl->op == &free_space_op)
1855                 block_group = ctl->private;
1856 again:
1857         /*
1858          * Since we link bitmaps right into the cluster we need to see if we
1859          * have a cluster here, and if so and it has our bitmap we need to add
1860          * the free space to that bitmap.
1861          */
1862         if (block_group && !list_empty(&block_group->cluster_list)) {
1863                 struct btrfs_free_cluster *cluster;
1864                 struct rb_node *node;
1865                 struct btrfs_free_space *entry;
1866
1867                 cluster = list_entry(block_group->cluster_list.next,
1868                                      struct btrfs_free_cluster,
1869                                      block_group_list);
1870                 spin_lock(&cluster->lock);
1871                 node = rb_first(&cluster->root);
1872                 if (!node) {
1873                         spin_unlock(&cluster->lock);
1874                         goto no_cluster_bitmap;
1875                 }
1876
1877                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1878                 if (!entry->bitmap) {
1879                         spin_unlock(&cluster->lock);
1880                         goto no_cluster_bitmap;
1881                 }
1882
1883                 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1884                         bytes_added = add_bytes_to_bitmap(ctl, entry,
1885                                                           offset, bytes);
1886                         bytes -= bytes_added;
1887                         offset += bytes_added;
1888                 }
1889                 spin_unlock(&cluster->lock);
1890                 if (!bytes) {
1891                         ret = 1;
1892                         goto out;
1893                 }
1894         }
1895
1896 no_cluster_bitmap:
1897         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1898                                          1, 0);
1899         if (!bitmap_info) {
1900                 ASSERT(added == 0);
1901                 goto new_bitmap;
1902         }
1903
1904         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1905         bytes -= bytes_added;
1906         offset += bytes_added;
1907         added = 0;
1908
1909         if (!bytes) {
1910                 ret = 1;
1911                 goto out;
1912         } else
1913                 goto again;
1914
1915 new_bitmap:
1916         if (info && info->bitmap) {
1917                 add_new_bitmap(ctl, info, offset);
1918                 added = 1;
1919                 info = NULL;
1920                 goto again;
1921         } else {
1922                 spin_unlock(&ctl->tree_lock);
1923
1924                 /* no pre-allocated info, allocate a new one */
1925                 if (!info) {
1926                         info = kmem_cache_zalloc(btrfs_free_space_cachep,
1927                                                  GFP_NOFS);
1928                         if (!info) {
1929                                 spin_lock(&ctl->tree_lock);
1930                                 ret = -ENOMEM;
1931                                 goto out;
1932                         }
1933                 }
1934
1935                 /* allocate the bitmap */
1936                 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1937                 spin_lock(&ctl->tree_lock);
1938                 if (!info->bitmap) {
1939                         ret = -ENOMEM;
1940                         goto out;
1941                 }
1942                 goto again;
1943         }
1944
1945 out:
1946         if (info) {
1947                 if (info->bitmap)
1948                         kfree(info->bitmap);
1949                 kmem_cache_free(btrfs_free_space_cachep, info);
1950         }
1951
1952         return ret;
1953 }
1954
1955 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1956                           struct btrfs_free_space *info, bool update_stat)
1957 {
1958         struct btrfs_free_space *left_info;
1959         struct btrfs_free_space *right_info;
1960         bool merged = false;
1961         u64 offset = info->offset;
1962         u64 bytes = info->bytes;
1963
1964         /*
1965          * first we want to see if there is free space adjacent to the range we
1966          * are adding, if there is remove that struct and add a new one to
1967          * cover the entire range
1968          */
1969         right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1970         if (right_info && rb_prev(&right_info->offset_index))
1971                 left_info = rb_entry(rb_prev(&right_info->offset_index),
1972                                      struct btrfs_free_space, offset_index);
1973         else
1974                 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1975
1976         if (right_info && !right_info->bitmap) {
1977                 if (update_stat)
1978                         unlink_free_space(ctl, right_info);
1979                 else
1980                         __unlink_free_space(ctl, right_info);
1981                 info->bytes += right_info->bytes;
1982                 kmem_cache_free(btrfs_free_space_cachep, right_info);
1983                 merged = true;
1984         }
1985
1986         if (left_info && !left_info->bitmap &&
1987             left_info->offset + left_info->bytes == offset) {
1988                 if (update_stat)
1989                         unlink_free_space(ctl, left_info);
1990                 else
1991                         __unlink_free_space(ctl, left_info);
1992                 info->offset = left_info->offset;
1993                 info->bytes += left_info->bytes;
1994                 kmem_cache_free(btrfs_free_space_cachep, left_info);
1995                 merged = true;
1996         }
1997
1998         return merged;
1999 }
2000
2001 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
2002                            u64 offset, u64 bytes)
2003 {
2004         struct btrfs_free_space *info;
2005         int ret = 0;
2006
2007         info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2008         if (!info)
2009                 return -ENOMEM;
2010
2011         info->offset = offset;
2012         info->bytes = bytes;
2013
2014         spin_lock(&ctl->tree_lock);
2015
2016         if (try_merge_free_space(ctl, info, true))
2017                 goto link;
2018
2019         /*
2020          * There was no extent directly to the left or right of this new
2021          * extent then we know we're going to have to allocate a new extent, so
2022          * before we do that see if we need to drop this into a bitmap
2023          */
2024         ret = insert_into_bitmap(ctl, info);
2025         if (ret < 0) {
2026                 goto out;
2027         } else if (ret) {
2028                 ret = 0;
2029                 goto out;
2030         }
2031 link:
2032         ret = link_free_space(ctl, info);
2033         if (ret)
2034                 kmem_cache_free(btrfs_free_space_cachep, info);
2035 out:
2036         spin_unlock(&ctl->tree_lock);
2037
2038         if (ret) {
2039                 printk(KERN_CRIT "BTRFS: unable to add free space :%d\n", ret);
2040                 ASSERT(ret != -EEXIST);
2041         }
2042
2043         return ret;
2044 }
2045
2046 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
2047                             u64 offset, u64 bytes)
2048 {
2049         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2050         struct btrfs_free_space *info;
2051         int ret;
2052         bool re_search = false;
2053
2054         spin_lock(&ctl->tree_lock);
2055
2056 again:
2057         ret = 0;
2058         if (!bytes)
2059                 goto out_lock;
2060
2061         info = tree_search_offset(ctl, offset, 0, 0);
2062         if (!info) {
2063                 /*
2064                  * oops didn't find an extent that matched the space we wanted
2065                  * to remove, look for a bitmap instead
2066                  */
2067                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2068                                           1, 0);
2069                 if (!info) {
2070                         /*
2071                          * If we found a partial bit of our free space in a
2072                          * bitmap but then couldn't find the other part this may
2073                          * be a problem, so WARN about it.
2074                          */
2075                         WARN_ON(re_search);
2076                         goto out_lock;
2077                 }
2078         }
2079
2080         re_search = false;
2081         if (!info->bitmap) {
2082                 unlink_free_space(ctl, info);
2083                 if (offset == info->offset) {
2084                         u64 to_free = min(bytes, info->bytes);
2085
2086                         info->bytes -= to_free;
2087                         info->offset += to_free;
2088                         if (info->bytes) {
2089                                 ret = link_free_space(ctl, info);
2090                                 WARN_ON(ret);
2091                         } else {
2092                                 kmem_cache_free(btrfs_free_space_cachep, info);
2093                         }
2094
2095                         offset += to_free;
2096                         bytes -= to_free;
2097                         goto again;
2098                 } else {
2099                         u64 old_end = info->bytes + info->offset;
2100
2101                         info->bytes = offset - info->offset;
2102                         ret = link_free_space(ctl, info);
2103                         WARN_ON(ret);
2104                         if (ret)
2105                                 goto out_lock;
2106
2107                         /* Not enough bytes in this entry to satisfy us */
2108                         if (old_end < offset + bytes) {
2109                                 bytes -= old_end - offset;
2110                                 offset = old_end;
2111                                 goto again;
2112                         } else if (old_end == offset + bytes) {
2113                                 /* all done */
2114                                 goto out_lock;
2115                         }
2116                         spin_unlock(&ctl->tree_lock);
2117
2118                         ret = btrfs_add_free_space(block_group, offset + bytes,
2119                                                    old_end - (offset + bytes));
2120                         WARN_ON(ret);
2121                         goto out;
2122                 }
2123         }
2124
2125         ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2126         if (ret == -EAGAIN) {
2127                 re_search = true;
2128                 goto again;
2129         }
2130 out_lock:
2131         spin_unlock(&ctl->tree_lock);
2132 out:
2133         return ret;
2134 }
2135
2136 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
2137                            u64 bytes)
2138 {
2139         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2140         struct btrfs_free_space *info;
2141         struct rb_node *n;
2142         int count = 0;
2143
2144         for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2145                 info = rb_entry(n, struct btrfs_free_space, offset_index);
2146                 if (info->bytes >= bytes && !block_group->ro)
2147                         count++;
2148                 btrfs_crit(block_group->fs_info,
2149                            "entry offset %llu, bytes %llu, bitmap %s",
2150                            info->offset, info->bytes,
2151                        (info->bitmap) ? "yes" : "no");
2152         }
2153         btrfs_info(block_group->fs_info, "block group has cluster?: %s",
2154                list_empty(&block_group->cluster_list) ? "no" : "yes");
2155         btrfs_info(block_group->fs_info,
2156                    "%d blocks of free space at or bigger than bytes is", count);
2157 }
2158
2159 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2160 {
2161         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2162
2163         spin_lock_init(&ctl->tree_lock);
2164         ctl->unit = block_group->sectorsize;
2165         ctl->start = block_group->key.objectid;
2166         ctl->private = block_group;
2167         ctl->op = &free_space_op;
2168
2169         /*
2170          * we only want to have 32k of ram per block group for keeping
2171          * track of free space, and if we pass 1/2 of that we want to
2172          * start converting things over to using bitmaps
2173          */
2174         ctl->extents_thresh = ((1024 * 32) / 2) /
2175                                 sizeof(struct btrfs_free_space);
2176 }
2177
2178 /*
2179  * for a given cluster, put all of its extents back into the free
2180  * space cache.  If the block group passed doesn't match the block group
2181  * pointed to by the cluster, someone else raced in and freed the
2182  * cluster already.  In that case, we just return without changing anything
2183  */
2184 static int
2185 __btrfs_return_cluster_to_free_space(
2186                              struct btrfs_block_group_cache *block_group,
2187                              struct btrfs_free_cluster *cluster)
2188 {
2189         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2190         struct btrfs_free_space *entry;
2191         struct rb_node *node;
2192
2193         spin_lock(&cluster->lock);
2194         if (cluster->block_group != block_group)
2195                 goto out;
2196
2197         cluster->block_group = NULL;
2198         cluster->window_start = 0;
2199         list_del_init(&cluster->block_group_list);
2200
2201         node = rb_first(&cluster->root);
2202         while (node) {
2203                 bool bitmap;
2204
2205                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2206                 node = rb_next(&entry->offset_index);
2207                 rb_erase(&entry->offset_index, &cluster->root);
2208
2209                 bitmap = (entry->bitmap != NULL);
2210                 if (!bitmap)
2211                         try_merge_free_space(ctl, entry, false);
2212                 tree_insert_offset(&ctl->free_space_offset,
2213                                    entry->offset, &entry->offset_index, bitmap);
2214         }
2215         cluster->root = RB_ROOT;
2216
2217 out:
2218         spin_unlock(&cluster->lock);
2219         btrfs_put_block_group(block_group);
2220         return 0;
2221 }
2222
2223 static void __btrfs_remove_free_space_cache_locked(
2224                                 struct btrfs_free_space_ctl *ctl)
2225 {
2226         struct btrfs_free_space *info;
2227         struct rb_node *node;
2228
2229         while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2230                 info = rb_entry(node, struct btrfs_free_space, offset_index);
2231                 if (!info->bitmap) {
2232                         unlink_free_space(ctl, info);
2233                         kmem_cache_free(btrfs_free_space_cachep, info);
2234                 } else {
2235                         free_bitmap(ctl, info);
2236                 }
2237                 if (need_resched()) {
2238                         spin_unlock(&ctl->tree_lock);
2239                         cond_resched();
2240                         spin_lock(&ctl->tree_lock);
2241                 }
2242         }
2243 }
2244
2245 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2246 {
2247         spin_lock(&ctl->tree_lock);
2248         __btrfs_remove_free_space_cache_locked(ctl);
2249         spin_unlock(&ctl->tree_lock);
2250 }
2251
2252 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2253 {
2254         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2255         struct btrfs_free_cluster *cluster;
2256         struct list_head *head;
2257
2258         spin_lock(&ctl->tree_lock);
2259         while ((head = block_group->cluster_list.next) !=
2260                &block_group->cluster_list) {
2261                 cluster = list_entry(head, struct btrfs_free_cluster,
2262                                      block_group_list);
2263
2264                 WARN_ON(cluster->block_group != block_group);
2265                 __btrfs_return_cluster_to_free_space(block_group, cluster);
2266                 if (need_resched()) {
2267                         spin_unlock(&ctl->tree_lock);
2268                         cond_resched();
2269                         spin_lock(&ctl->tree_lock);
2270                 }
2271         }
2272         __btrfs_remove_free_space_cache_locked(ctl);
2273         spin_unlock(&ctl->tree_lock);
2274
2275 }
2276
2277 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2278                                u64 offset, u64 bytes, u64 empty_size,
2279                                u64 *max_extent_size)
2280 {
2281         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2282         struct btrfs_free_space *entry = NULL;
2283         u64 bytes_search = bytes + empty_size;
2284         u64 ret = 0;
2285         u64 align_gap = 0;
2286         u64 align_gap_len = 0;
2287
2288         spin_lock(&ctl->tree_lock);
2289         entry = find_free_space(ctl, &offset, &bytes_search,
2290                                 block_group->full_stripe_len, max_extent_size);
2291         if (!entry)
2292                 goto out;
2293
2294         ret = offset;
2295         if (entry->bitmap) {
2296                 bitmap_clear_bits(ctl, entry, offset, bytes);
2297                 if (!entry->bytes)
2298                         free_bitmap(ctl, entry);
2299         } else {
2300                 unlink_free_space(ctl, entry);
2301                 align_gap_len = offset - entry->offset;
2302                 align_gap = entry->offset;
2303
2304                 entry->offset = offset + bytes;
2305                 WARN_ON(entry->bytes < bytes + align_gap_len);
2306
2307                 entry->bytes -= bytes + align_gap_len;
2308                 if (!entry->bytes)
2309                         kmem_cache_free(btrfs_free_space_cachep, entry);
2310                 else
2311                         link_free_space(ctl, entry);
2312         }
2313 out:
2314         spin_unlock(&ctl->tree_lock);
2315
2316         if (align_gap_len)
2317                 __btrfs_add_free_space(ctl, align_gap, align_gap_len);
2318         return ret;
2319 }
2320
2321 /*
2322  * given a cluster, put all of its extents back into the free space
2323  * cache.  If a block group is passed, this function will only free
2324  * a cluster that belongs to the passed block group.
2325  *
2326  * Otherwise, it'll get a reference on the block group pointed to by the
2327  * cluster and remove the cluster from it.
2328  */
2329 int btrfs_return_cluster_to_free_space(
2330                                struct btrfs_block_group_cache *block_group,
2331                                struct btrfs_free_cluster *cluster)
2332 {
2333         struct btrfs_free_space_ctl *ctl;
2334         int ret;
2335
2336         /* first, get a safe pointer to the block group */
2337         spin_lock(&cluster->lock);
2338         if (!block_group) {
2339                 block_group = cluster->block_group;
2340                 if (!block_group) {
2341                         spin_unlock(&cluster->lock);
2342                         return 0;
2343                 }
2344         } else if (cluster->block_group != block_group) {
2345                 /* someone else has already freed it don't redo their work */
2346                 spin_unlock(&cluster->lock);
2347                 return 0;
2348         }
2349         atomic_inc(&block_group->count);
2350         spin_unlock(&cluster->lock);
2351
2352         ctl = block_group->free_space_ctl;
2353
2354         /* now return any extents the cluster had on it */
2355         spin_lock(&ctl->tree_lock);
2356         ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2357         spin_unlock(&ctl->tree_lock);
2358
2359         /* finally drop our ref */
2360         btrfs_put_block_group(block_group);
2361         return ret;
2362 }
2363
2364 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2365                                    struct btrfs_free_cluster *cluster,
2366                                    struct btrfs_free_space *entry,
2367                                    u64 bytes, u64 min_start,
2368                                    u64 *max_extent_size)
2369 {
2370         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2371         int err;
2372         u64 search_start = cluster->window_start;
2373         u64 search_bytes = bytes;
2374         u64 ret = 0;
2375
2376         search_start = min_start;
2377         search_bytes = bytes;
2378
2379         err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2380         if (err) {
2381                 if (search_bytes > *max_extent_size)
2382                         *max_extent_size = search_bytes;
2383                 return 0;
2384         }
2385
2386         ret = search_start;
2387         __bitmap_clear_bits(ctl, entry, ret, bytes);
2388
2389         return ret;
2390 }
2391
2392 /*
2393  * given a cluster, try to allocate 'bytes' from it, returns 0
2394  * if it couldn't find anything suitably large, or a logical disk offset
2395  * if things worked out
2396  */
2397 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2398                              struct btrfs_free_cluster *cluster, u64 bytes,
2399                              u64 min_start, u64 *max_extent_size)
2400 {
2401         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2402         struct btrfs_free_space *entry = NULL;
2403         struct rb_node *node;
2404         u64 ret = 0;
2405
2406         spin_lock(&cluster->lock);
2407         if (bytes > cluster->max_size)
2408                 goto out;
2409
2410         if (cluster->block_group != block_group)
2411                 goto out;
2412
2413         node = rb_first(&cluster->root);
2414         if (!node)
2415                 goto out;
2416
2417         entry = rb_entry(node, struct btrfs_free_space, offset_index);
2418         while (1) {
2419                 if (entry->bytes < bytes && entry->bytes > *max_extent_size)
2420                         *max_extent_size = entry->bytes;
2421
2422                 if (entry->bytes < bytes ||
2423                     (!entry->bitmap && entry->offset < min_start)) {
2424                         node = rb_next(&entry->offset_index);
2425                         if (!node)
2426                                 break;
2427                         entry = rb_entry(node, struct btrfs_free_space,
2428                                          offset_index);
2429                         continue;
2430                 }
2431
2432                 if (entry->bitmap) {
2433                         ret = btrfs_alloc_from_bitmap(block_group,
2434                                                       cluster, entry, bytes,
2435                                                       cluster->window_start,
2436                                                       max_extent_size);
2437                         if (ret == 0) {
2438                                 node = rb_next(&entry->offset_index);
2439                                 if (!node)
2440                                         break;
2441                                 entry = rb_entry(node, struct btrfs_free_space,
2442                                                  offset_index);
2443                                 continue;
2444                         }
2445                         cluster->window_start += bytes;
2446                 } else {
2447                         ret = entry->offset;
2448
2449                         entry->offset += bytes;
2450                         entry->bytes -= bytes;
2451                 }
2452
2453                 if (entry->bytes == 0)
2454                         rb_erase(&entry->offset_index, &cluster->root);
2455                 break;
2456         }
2457 out:
2458         spin_unlock(&cluster->lock);
2459
2460         if (!ret)
2461                 return 0;
2462
2463         spin_lock(&ctl->tree_lock);
2464
2465         ctl->free_space -= bytes;
2466         if (entry->bytes == 0) {
2467                 ctl->free_extents--;
2468                 if (entry->bitmap) {
2469                         kfree(entry->bitmap);
2470                         ctl->total_bitmaps--;
2471                         ctl->op->recalc_thresholds(ctl);
2472                 }
2473                 kmem_cache_free(btrfs_free_space_cachep, entry);
2474         }
2475
2476         spin_unlock(&ctl->tree_lock);
2477
2478         return ret;
2479 }
2480
2481 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2482                                 struct btrfs_free_space *entry,
2483                                 struct btrfs_free_cluster *cluster,
2484                                 u64 offset, u64 bytes,
2485                                 u64 cont1_bytes, u64 min_bytes)
2486 {
2487         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2488         unsigned long next_zero;
2489         unsigned long i;
2490         unsigned long want_bits;
2491         unsigned long min_bits;
2492         unsigned long found_bits;
2493         unsigned long start = 0;
2494         unsigned long total_found = 0;
2495         int ret;
2496
2497         i = offset_to_bit(entry->offset, ctl->unit,
2498                           max_t(u64, offset, entry->offset));
2499         want_bits = bytes_to_bits(bytes, ctl->unit);
2500         min_bits = bytes_to_bits(min_bytes, ctl->unit);
2501
2502 again:
2503         found_bits = 0;
2504         for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2505                 next_zero = find_next_zero_bit(entry->bitmap,
2506                                                BITS_PER_BITMAP, i);
2507                 if (next_zero - i >= min_bits) {
2508                         found_bits = next_zero - i;
2509                         break;
2510                 }
2511                 i = next_zero;
2512         }
2513
2514         if (!found_bits)
2515                 return -ENOSPC;
2516
2517         if (!total_found) {
2518                 start = i;
2519                 cluster->max_size = 0;
2520         }
2521
2522         total_found += found_bits;
2523
2524         if (cluster->max_size < found_bits * ctl->unit)
2525                 cluster->max_size = found_bits * ctl->unit;
2526
2527         if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2528                 i = next_zero + 1;
2529                 goto again;
2530         }
2531
2532         cluster->window_start = start * ctl->unit + entry->offset;
2533         rb_erase(&entry->offset_index, &ctl->free_space_offset);
2534         ret = tree_insert_offset(&cluster->root, entry->offset,
2535                                  &entry->offset_index, 1);
2536         ASSERT(!ret); /* -EEXIST; Logic error */
2537
2538         trace_btrfs_setup_cluster(block_group, cluster,
2539                                   total_found * ctl->unit, 1);
2540         return 0;
2541 }
2542
2543 /*
2544  * This searches the block group for just extents to fill the cluster with.
2545  * Try to find a cluster with at least bytes total bytes, at least one
2546  * extent of cont1_bytes, and other clusters of at least min_bytes.
2547  */
2548 static noinline int
2549 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2550                         struct btrfs_free_cluster *cluster,
2551                         struct list_head *bitmaps, u64 offset, u64 bytes,
2552                         u64 cont1_bytes, u64 min_bytes)
2553 {
2554         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2555         struct btrfs_free_space *first = NULL;
2556         struct btrfs_free_space *entry = NULL;
2557         struct btrfs_free_space *last;
2558         struct rb_node *node;
2559         u64 window_free;
2560         u64 max_extent;
2561         u64 total_size = 0;
2562
2563         entry = tree_search_offset(ctl, offset, 0, 1);
2564         if (!entry)
2565                 return -ENOSPC;
2566
2567         /*
2568          * We don't want bitmaps, so just move along until we find a normal
2569          * extent entry.
2570          */
2571         while (entry->bitmap || entry->bytes < min_bytes) {
2572                 if (entry->bitmap && list_empty(&entry->list))
2573                         list_add_tail(&entry->list, bitmaps);
2574                 node = rb_next(&entry->offset_index);
2575                 if (!node)
2576                         return -ENOSPC;
2577                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2578         }
2579
2580         window_free = entry->bytes;
2581         max_extent = entry->bytes;
2582         first = entry;
2583         last = entry;
2584
2585         for (node = rb_next(&entry->offset_index); node;
2586              node = rb_next(&entry->offset_index)) {
2587                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2588
2589                 if (entry->bitmap) {
2590                         if (list_empty(&entry->list))
2591                                 list_add_tail(&entry->list, bitmaps);
2592                         continue;
2593                 }
2594
2595                 if (entry->bytes < min_bytes)
2596                         continue;
2597
2598                 last = entry;
2599                 window_free += entry->bytes;
2600                 if (entry->bytes > max_extent)
2601                         max_extent = entry->bytes;
2602         }
2603
2604         if (window_free < bytes || max_extent < cont1_bytes)
2605                 return -ENOSPC;
2606
2607         cluster->window_start = first->offset;
2608
2609         node = &first->offset_index;
2610
2611         /*
2612          * now we've found our entries, pull them out of the free space
2613          * cache and put them into the cluster rbtree
2614          */
2615         do {
2616                 int ret;
2617
2618                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2619                 node = rb_next(&entry->offset_index);
2620                 if (entry->bitmap || entry->bytes < min_bytes)
2621                         continue;
2622
2623                 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2624                 ret = tree_insert_offset(&cluster->root, entry->offset,
2625                                          &entry->offset_index, 0);
2626                 total_size += entry->bytes;
2627                 ASSERT(!ret); /* -EEXIST; Logic error */
2628         } while (node && entry != last);
2629
2630         cluster->max_size = max_extent;
2631         trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2632         return 0;
2633 }
2634
2635 /*
2636  * This specifically looks for bitmaps that may work in the cluster, we assume
2637  * that we have already failed to find extents that will work.
2638  */
2639 static noinline int
2640 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2641                      struct btrfs_free_cluster *cluster,
2642                      struct list_head *bitmaps, u64 offset, u64 bytes,
2643                      u64 cont1_bytes, u64 min_bytes)
2644 {
2645         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2646         struct btrfs_free_space *entry;
2647         int ret = -ENOSPC;
2648         u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2649
2650         if (ctl->total_bitmaps == 0)
2651                 return -ENOSPC;
2652
2653         /*
2654          * The bitmap that covers offset won't be in the list unless offset
2655          * is just its start offset.
2656          */
2657         entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2658         if (entry->offset != bitmap_offset) {
2659                 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2660                 if (entry && list_empty(&entry->list))
2661                         list_add(&entry->list, bitmaps);
2662         }
2663
2664         list_for_each_entry(entry, bitmaps, list) {
2665                 if (entry->bytes < bytes)
2666                         continue;
2667                 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2668                                            bytes, cont1_bytes, min_bytes);
2669                 if (!ret)
2670                         return 0;
2671         }
2672
2673         /*
2674          * The bitmaps list has all the bitmaps that record free space
2675          * starting after offset, so no more search is required.
2676          */
2677         return -ENOSPC;
2678 }
2679
2680 /*
2681  * here we try to find a cluster of blocks in a block group.  The goal
2682  * is to find at least bytes+empty_size.
2683  * We might not find them all in one contiguous area.
2684  *
2685  * returns zero and sets up cluster if things worked out, otherwise
2686  * it returns -enospc
2687  */
2688 int btrfs_find_space_cluster(struct btrfs_root *root,
2689                              struct btrfs_block_group_cache *block_group,
2690                              struct btrfs_free_cluster *cluster,
2691                              u64 offset, u64 bytes, u64 empty_size)
2692 {
2693         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2694         struct btrfs_free_space *entry, *tmp;
2695         LIST_HEAD(bitmaps);
2696         u64 min_bytes;
2697         u64 cont1_bytes;
2698         int ret;
2699
2700         /*
2701          * Choose the minimum extent size we'll require for this
2702          * cluster.  For SSD_SPREAD, don't allow any fragmentation.
2703          * For metadata, allow allocates with smaller extents.  For
2704          * data, keep it dense.
2705          */
2706         if (btrfs_test_opt(root, SSD_SPREAD)) {
2707                 cont1_bytes = min_bytes = bytes + empty_size;
2708         } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2709                 cont1_bytes = bytes;
2710                 min_bytes = block_group->sectorsize;
2711         } else {
2712                 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2713                 min_bytes = block_group->sectorsize;
2714         }
2715
2716         spin_lock(&ctl->tree_lock);
2717
2718         /*
2719          * If we know we don't have enough space to make a cluster don't even
2720          * bother doing all the work to try and find one.
2721          */
2722         if (ctl->free_space < bytes) {
2723                 spin_unlock(&ctl->tree_lock);
2724                 return -ENOSPC;
2725         }
2726
2727         spin_lock(&cluster->lock);
2728
2729         /* someone already found a cluster, hooray */
2730         if (cluster->block_group) {
2731                 ret = 0;
2732                 goto out;
2733         }
2734
2735         trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
2736                                  min_bytes);
2737
2738         INIT_LIST_HEAD(&bitmaps);
2739         ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2740                                       bytes + empty_size,
2741                                       cont1_bytes, min_bytes);
2742         if (ret)
2743                 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2744                                            offset, bytes + empty_size,
2745                                            cont1_bytes, min_bytes);
2746
2747         /* Clear our temporary list */
2748         list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2749                 list_del_init(&entry->list);
2750
2751         if (!ret) {
2752                 atomic_inc(&block_group->count);
2753                 list_add_tail(&cluster->block_group_list,
2754                               &block_group->cluster_list);
2755                 cluster->block_group = block_group;
2756         } else {
2757                 trace_btrfs_failed_cluster_setup(block_group);
2758         }
2759 out:
2760         spin_unlock(&cluster->lock);
2761         spin_unlock(&ctl->tree_lock);
2762
2763         return ret;
2764 }
2765
2766 /*
2767  * simple code to zero out a cluster
2768  */
2769 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2770 {
2771         spin_lock_init(&cluster->lock);
2772         spin_lock_init(&cluster->refill_lock);
2773         cluster->root = RB_ROOT;
2774         cluster->max_size = 0;
2775         INIT_LIST_HEAD(&cluster->block_group_list);
2776         cluster->block_group = NULL;
2777 }
2778
2779 static int do_trimming(struct btrfs_block_group_cache *block_group,
2780                        u64 *total_trimmed, u64 start, u64 bytes,
2781                        u64 reserved_start, u64 reserved_bytes)
2782 {
2783         struct btrfs_space_info *space_info = block_group->space_info;
2784         struct btrfs_fs_info *fs_info = block_group->fs_info;
2785         int ret;
2786         int update = 0;
2787         u64 trimmed = 0;
2788
2789         spin_lock(&space_info->lock);
2790         spin_lock(&block_group->lock);
2791         if (!block_group->ro) {
2792                 block_group->reserved += reserved_bytes;
2793                 space_info->bytes_reserved += reserved_bytes;
2794                 update = 1;
2795         }
2796         spin_unlock(&block_group->lock);
2797         spin_unlock(&space_info->lock);
2798
2799         ret = btrfs_error_discard_extent(fs_info->extent_root,
2800                                          start, bytes, &trimmed);
2801         if (!ret)
2802                 *total_trimmed += trimmed;
2803
2804         btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
2805
2806         if (update) {
2807                 spin_lock(&space_info->lock);
2808                 spin_lock(&block_group->lock);
2809                 if (block_group->ro)
2810                         space_info->bytes_readonly += reserved_bytes;
2811                 block_group->reserved -= reserved_bytes;
2812                 space_info->bytes_reserved -= reserved_bytes;
2813                 spin_unlock(&space_info->lock);
2814                 spin_unlock(&block_group->lock);
2815         }
2816
2817         return ret;
2818 }
2819
2820 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
2821                           u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2822 {
2823         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2824         struct btrfs_free_space *entry;
2825         struct rb_node *node;
2826         int ret = 0;
2827         u64 extent_start;
2828         u64 extent_bytes;
2829         u64 bytes;
2830
2831         while (start < end) {
2832                 spin_lock(&ctl->tree_lock);
2833
2834                 if (ctl->free_space < minlen) {
2835                         spin_unlock(&ctl->tree_lock);
2836                         break;
2837                 }
2838
2839                 entry = tree_search_offset(ctl, start, 0, 1);
2840                 if (!entry) {
2841                         spin_unlock(&ctl->tree_lock);
2842                         break;
2843                 }
2844
2845                 /* skip bitmaps */
2846                 while (entry->bitmap) {
2847                         node = rb_next(&entry->offset_index);
2848                         if (!node) {
2849                                 spin_unlock(&ctl->tree_lock);
2850                                 goto out;
2851                         }
2852                         entry = rb_entry(node, struct btrfs_free_space,
2853                                          offset_index);
2854                 }
2855
2856                 if (entry->offset >= end) {
2857                         spin_unlock(&ctl->tree_lock);
2858                         break;
2859                 }
2860
2861                 extent_start = entry->offset;
2862                 extent_bytes = entry->bytes;
2863                 start = max(start, extent_start);
2864                 bytes = min(extent_start + extent_bytes, end) - start;
2865                 if (bytes < minlen) {
2866                         spin_unlock(&ctl->tree_lock);
2867                         goto next;
2868                 }
2869
2870                 unlink_free_space(ctl, entry);
2871                 kmem_cache_free(btrfs_free_space_cachep, entry);
2872
2873                 spin_unlock(&ctl->tree_lock);
2874
2875                 ret = do_trimming(block_group, total_trimmed, start, bytes,
2876                                   extent_start, extent_bytes);
2877                 if (ret)
2878                         break;
2879 next:
2880                 start += bytes;
2881
2882                 if (fatal_signal_pending(current)) {
2883                         ret = -ERESTARTSYS;
2884                         break;
2885                 }
2886
2887                 cond_resched();
2888         }
2889 out:
2890         return ret;
2891 }
2892
2893 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
2894                         u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2895 {
2896         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2897         struct btrfs_free_space *entry;
2898         int ret = 0;
2899         int ret2;
2900         u64 bytes;
2901         u64 offset = offset_to_bitmap(ctl, start);
2902
2903         while (offset < end) {
2904                 bool next_bitmap = false;
2905
2906                 spin_lock(&ctl->tree_lock);
2907
2908                 if (ctl->free_space < minlen) {
2909                         spin_unlock(&ctl->tree_lock);
2910                         break;
2911                 }
2912
2913                 entry = tree_search_offset(ctl, offset, 1, 0);
2914                 if (!entry) {
2915                         spin_unlock(&ctl->tree_lock);
2916                         next_bitmap = true;
2917                         goto next;
2918                 }
2919
2920                 bytes = minlen;
2921                 ret2 = search_bitmap(ctl, entry, &start, &bytes);
2922                 if (ret2 || start >= end) {
2923                         spin_unlock(&ctl->tree_lock);
2924                         next_bitmap = true;
2925                         goto next;
2926                 }
2927
2928                 bytes = min(bytes, end - start);
2929                 if (bytes < minlen) {
2930                         spin_unlock(&ctl->tree_lock);
2931                         goto next;
2932                 }
2933
2934                 bitmap_clear_bits(ctl, entry, start, bytes);
2935                 if (entry->bytes == 0)
2936                         free_bitmap(ctl, entry);
2937
2938                 spin_unlock(&ctl->tree_lock);
2939
2940                 ret = do_trimming(block_group, total_trimmed, start, bytes,
2941                                   start, bytes);
2942                 if (ret)
2943                         break;
2944 next:
2945                 if (next_bitmap) {
2946                         offset += BITS_PER_BITMAP * ctl->unit;
2947                 } else {
2948                         start += bytes;
2949                         if (start >= offset + BITS_PER_BITMAP * ctl->unit)
2950                                 offset += BITS_PER_BITMAP * ctl->unit;
2951                 }
2952
2953                 if (fatal_signal_pending(current)) {
2954                         ret = -ERESTARTSYS;
2955                         break;
2956                 }
2957
2958                 cond_resched();
2959         }
2960
2961         return ret;
2962 }
2963
2964 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2965                            u64 *trimmed, u64 start, u64 end, u64 minlen)
2966 {
2967         int ret;
2968
2969         *trimmed = 0;
2970
2971         ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
2972         if (ret)
2973                 return ret;
2974
2975         ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
2976
2977         return ret;
2978 }
2979
2980 /*
2981  * Find the left-most item in the cache tree, and then return the
2982  * smallest inode number in the item.
2983  *
2984  * Note: the returned inode number may not be the smallest one in
2985  * the tree, if the left-most item is a bitmap.
2986  */
2987 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2988 {
2989         struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2990         struct btrfs_free_space *entry = NULL;
2991         u64 ino = 0;
2992
2993         spin_lock(&ctl->tree_lock);
2994
2995         if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2996                 goto out;
2997
2998         entry = rb_entry(rb_first(&ctl->free_space_offset),
2999                          struct btrfs_free_space, offset_index);
3000
3001         if (!entry->bitmap) {
3002                 ino = entry->offset;
3003
3004                 unlink_free_space(ctl, entry);
3005                 entry->offset++;
3006                 entry->bytes--;
3007                 if (!entry->bytes)
3008                         kmem_cache_free(btrfs_free_space_cachep, entry);
3009                 else
3010                         link_free_space(ctl, entry);
3011         } else {
3012                 u64 offset = 0;
3013                 u64 count = 1;
3014                 int ret;
3015
3016                 ret = search_bitmap(ctl, entry, &offset, &count);
3017                 /* Logic error; Should be empty if it can't find anything */
3018                 ASSERT(!ret);
3019
3020                 ino = offset;
3021                 bitmap_clear_bits(ctl, entry, offset, 1);
3022                 if (entry->bytes == 0)
3023                         free_bitmap(ctl, entry);
3024         }
3025 out:
3026         spin_unlock(&ctl->tree_lock);
3027
3028         return ino;
3029 }
3030
3031 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
3032                                     struct btrfs_path *path)
3033 {
3034         struct inode *inode = NULL;
3035
3036         spin_lock(&root->cache_lock);
3037         if (root->cache_inode)
3038                 inode = igrab(root->cache_inode);
3039         spin_unlock(&root->cache_lock);
3040         if (inode)
3041                 return inode;
3042
3043         inode = __lookup_free_space_inode(root, path, 0);
3044         if (IS_ERR(inode))
3045                 return inode;
3046
3047         spin_lock(&root->cache_lock);
3048         if (!btrfs_fs_closing(root->fs_info))
3049                 root->cache_inode = igrab(inode);
3050         spin_unlock(&root->cache_lock);
3051
3052         return inode;
3053 }
3054
3055 int create_free_ino_inode(struct btrfs_root *root,
3056                           struct btrfs_trans_handle *trans,
3057                           struct btrfs_path *path)
3058 {
3059         return __create_free_space_inode(root, trans, path,
3060                                          BTRFS_FREE_INO_OBJECTID, 0);
3061 }
3062
3063 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
3064 {
3065         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3066         struct btrfs_path *path;
3067         struct inode *inode;
3068         int ret = 0;
3069         u64 root_gen = btrfs_root_generation(&root->root_item);
3070
3071         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3072                 return 0;
3073
3074         /*
3075          * If we're unmounting then just return, since this does a search on the
3076          * normal root and not the commit root and we could deadlock.
3077          */
3078         if (btrfs_fs_closing(fs_info))
3079                 return 0;
3080
3081         path = btrfs_alloc_path();
3082         if (!path)
3083                 return 0;
3084
3085         inode = lookup_free_ino_inode(root, path);
3086         if (IS_ERR(inode))
3087                 goto out;
3088
3089         if (root_gen != BTRFS_I(inode)->generation)
3090                 goto out_put;
3091
3092         ret = __load_free_space_cache(root, inode, ctl, path, 0);
3093
3094         if (ret < 0)
3095                 btrfs_err(fs_info,
3096                         "failed to load free ino cache for root %llu",
3097                         root->root_key.objectid);
3098 out_put:
3099         iput(inode);
3100 out:
3101         btrfs_free_path(path);
3102         return ret;
3103 }
3104
3105 int btrfs_write_out_ino_cache(struct btrfs_root *root,
3106                               struct btrfs_trans_handle *trans,
3107                               struct btrfs_path *path,
3108                               struct inode *inode)
3109 {
3110         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3111         int ret;
3112
3113         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3114                 return 0;
3115
3116         ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
3117         if (ret) {
3118                 btrfs_delalloc_release_metadata(inode, inode->i_size);
3119 #ifdef DEBUG
3120                 btrfs_err(root->fs_info,
3121                         "failed to write free ino cache for root %llu",
3122                         root->root_key.objectid);
3123 #endif
3124         }
3125
3126         return ret;
3127 }
3128
3129 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3130 /*
3131  * Use this if you need to make a bitmap or extent entry specifically, it
3132  * doesn't do any of the merging that add_free_space does, this acts a lot like
3133  * how the free space cache loading stuff works, so you can get really weird
3134  * configurations.
3135  */
3136 int test_add_free_space_entry(struct btrfs_block_group_cache *cache,
3137                               u64 offset, u64 bytes, bool bitmap)
3138 {
3139         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3140         struct btrfs_free_space *info = NULL, *bitmap_info;
3141         void *map = NULL;
3142         u64 bytes_added;
3143         int ret;
3144
3145 again:
3146         if (!info) {
3147                 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3148                 if (!info)
3149                         return -ENOMEM;
3150         }
3151
3152         if (!bitmap) {
3153                 spin_lock(&ctl->tree_lock);
3154                 info->offset = offset;
3155                 info->bytes = bytes;
3156                 ret = link_free_space(ctl, info);
3157                 spin_unlock(&ctl->tree_lock);
3158                 if (ret)
3159                         kmem_cache_free(btrfs_free_space_cachep, info);
3160                 return ret;
3161         }
3162
3163         if (!map) {
3164                 map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
3165                 if (!map) {
3166                         kmem_cache_free(btrfs_free_space_cachep, info);
3167                         return -ENOMEM;
3168                 }
3169         }
3170
3171         spin_lock(&ctl->tree_lock);
3172         bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3173                                          1, 0);
3174         if (!bitmap_info) {
3175                 info->bitmap = map;
3176                 map = NULL;
3177                 add_new_bitmap(ctl, info, offset);
3178                 bitmap_info = info;
3179         }
3180
3181         bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3182         bytes -= bytes_added;
3183         offset += bytes_added;
3184         spin_unlock(&ctl->tree_lock);
3185
3186         if (bytes)
3187                 goto again;
3188
3189         if (map)
3190                 kfree(map);
3191         return 0;
3192 }
3193
3194 /*
3195  * Checks to see if the given range is in the free space cache.  This is really
3196  * just used to check the absence of space, so if there is free space in the
3197  * range at all we will return 1.
3198  */
3199 int test_check_exists(struct btrfs_block_group_cache *cache,
3200                       u64 offset, u64 bytes)
3201 {
3202         struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3203         struct btrfs_free_space *info;
3204         int ret = 0;
3205
3206         spin_lock(&ctl->tree_lock);
3207         info = tree_search_offset(ctl, offset, 0, 0);
3208         if (!info) {
3209                 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3210                                           1, 0);
3211                 if (!info)
3212                         goto out;
3213         }
3214
3215 have_info:
3216         if (info->bitmap) {
3217                 u64 bit_off, bit_bytes;
3218                 struct rb_node *n;
3219                 struct btrfs_free_space *tmp;
3220
3221                 bit_off = offset;
3222                 bit_bytes = ctl->unit;
3223                 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
3224                 if (!ret) {
3225                         if (bit_off == offset) {
3226                                 ret = 1;
3227                                 goto out;
3228                         } else if (bit_off > offset &&
3229                                    offset + bytes > bit_off) {
3230                                 ret = 1;
3231                                 goto out;
3232                         }
3233                 }
3234
3235                 n = rb_prev(&info->offset_index);
3236                 while (n) {
3237                         tmp = rb_entry(n, struct btrfs_free_space,
3238                                        offset_index);
3239                         if (tmp->offset + tmp->bytes < offset)
3240                                 break;
3241                         if (offset + bytes < tmp->offset) {
3242                                 n = rb_prev(&info->offset_index);
3243                                 continue;
3244                         }
3245                         info = tmp;
3246                         goto have_info;
3247                 }
3248
3249                 n = rb_next(&info->offset_index);
3250                 while (n) {
3251                         tmp = rb_entry(n, struct btrfs_free_space,
3252                                        offset_index);
3253                         if (offset + bytes < tmp->offset)
3254                                 break;
3255                         if (tmp->offset + tmp->bytes < offset) {
3256                                 n = rb_next(&info->offset_index);
3257                                 continue;
3258                         }
3259                         info = tmp;
3260                         goto have_info;
3261                 }
3262
3263                 goto out;
3264         }
3265
3266         if (info->offset == offset) {
3267                 ret = 1;
3268                 goto out;
3269         }
3270
3271         if (offset > info->offset && offset < info->offset + info->bytes)
3272                 ret = 1;
3273 out:
3274         spin_unlock(&ctl->tree_lock);
3275         return ret;
3276 }
3277 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */