fs/btrfs/ordered-data.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/slab.h>
  20 #include <linux/blkdev.h>
  21 #include <linux/writeback.h>
  22 #include <linux/pagevec.h>
  23 #include "ctree.h"
  24 #include "transaction.h"
  25 #include "btrfs_inode.h"
  26 #include "extent_io.h"
  27 #include "disk-io.h"
  28
  29 static struct kmem_cache *btrfs_ordered_extent_cache;
  30
  31 static u64 entry_end(struct btrfs_ordered_extent *entry)
  32 {
  33         if (entry->file_offset + entry->len < entry->file_offset)
  34                 return (u64)-1;
  35         return entry->file_offset + entry->len;
  36 }
  37
  38 /* returns NULL if the insertion worked, or it returns the node it did find
  39  * in the tree
  40  */
  41 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  42                                    struct rb_node *node)
  43 {
  44         struct rb_node **p = &root->rb_node;
  45         struct rb_node *parent = NULL;
  46         struct btrfs_ordered_extent *entry;
  47
  48         while (*p) {
  49                 parent = *p;
  50                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  51
  52                 if (file_offset < entry->file_offset)
  53                         p = &(*p)->rb_left;
  54                 else if (file_offset >= entry_end(entry))
  55                         p = &(*p)->rb_right;
  56                 else
  57                         return parent;
  58         }
  59
  60         rb_link_node(node, parent, p);
  61         rb_insert_color(node, root);
  62         return NULL;
  63 }
  64
  65 static void ordered_data_tree_panic(struct inode *inode, int errno,
  66                                                u64 offset)
  67 {
  68         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
  69         btrfs_panic(fs_info, errno, "Inconsistency in ordered tree at offset "
  70                     "%llu", offset);
  71 }
  72
  73 /*
  74  * look for a given offset in the tree, and if it can't be found return the
  75  * first lesser offset
  76  */
  77 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  78                                      struct rb_node **prev_ret)
  79 {
  80         struct rb_node *n = root->rb_node;
  81         struct rb_node *prev = NULL;
  82         struct rb_node *test;
  83         struct btrfs_ordered_extent *entry;
  84         struct btrfs_ordered_extent *prev_entry = NULL;
  85
  86         while (n) {
  87                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  88                 prev = n;
  89                 prev_entry = entry;
  90
  91                 if (file_offset < entry->file_offset)
  92                         n = n->rb_left;
  93                 else if (file_offset >= entry_end(entry))
  94                         n = n->rb_right;
  95                 else
  96                         return n;
  97         }
  98         if (!prev_ret)
  99                 return NULL;
 100
 101         while (prev && file_offset >= entry_end(prev_entry)) {
 102                 test = rb_next(prev);
 103                 if (!test)
 104                         break;
 105                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 106                                       rb_node);
 107                 if (file_offset < entry_end(prev_entry))
 108                         break;
 109
 110                 prev = test;
 111         }
 112         if (prev)
 113                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 114                                       rb_node);
 115         while (prev && file_offset < entry_end(prev_entry)) {
 116                 test = rb_prev(prev);
 117                 if (!test)
 118                         break;
 119                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 120                                       rb_node);
 121                 prev = test;
 122         }
 123         *prev_ret = prev;
 124         return NULL;
 125 }
 126
 127 /*
 128  * helper to check if a given offset is inside a given entry
 129  */
 130 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 131 {
 132         if (file_offset < entry->file_offset ||
 133             entry->file_offset + entry->len <= file_offset)
 134                 return 0;
 135         return 1;
 136 }
 137
 138 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 139                           u64 len)
 140 {
 141         if (file_offset + len <= entry->file_offset ||
 142             entry->file_offset + entry->len <= file_offset)
 143                 return 0;
 144         return 1;
 145 }
 146
 147 /*
 148  * look find the first ordered struct that has this offset, otherwise
 149  * the first one less than this offset
 150  */
 151 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 152                                           u64 file_offset)
 153 {
 154         struct rb_root *root = &tree->tree;
 155         struct rb_node *prev = NULL;
 156         struct rb_node *ret;
 157         struct btrfs_ordered_extent *entry;
 158
 159         if (tree->last) {
 160                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 161                                  rb_node);
 162                 if (offset_in_entry(entry, file_offset))
 163                         return tree->last;
 164         }
 165         ret = __tree_search(root, file_offset, &prev);
 166         if (!ret)
 167                 ret = prev;
 168         if (ret)
 169                 tree->last = ret;
 170         return ret;
 171 }
 172
 173 /* allocate and add a new ordered_extent into the per-inode tree.
 174  * file_offset is the logical offset in the file
 175  *
 176  * start is the disk block number of an extent already reserved in the
 177  * extent allocation tree
 178  *
 179  * len is the length of the extent
 180  *
 181  * The tree is given a single reference on the ordered extent that was
 182  * inserted.
 183  */
 184 static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 185                                       u64 start, u64 len, u64 disk_len,
 186                                       int type, int dio, int compress_type)
 187 {
 188         struct btrfs_root *root = BTRFS_I(inode)->root;
 189         struct btrfs_ordered_inode_tree *tree;
 190         struct rb_node *node;
 191         struct btrfs_ordered_extent *entry;
 192
 193         tree = &BTRFS_I(inode)->ordered_tree;
 194         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 195         if (!entry)
 196                 return -ENOMEM;
 197
 198         entry->file_offset = file_offset;
 199         entry->start = start;
 200         entry->len = len;
 201         entry->disk_len = disk_len;
 202         entry->bytes_left = len;
 203         entry->inode = igrab(inode);
 204         entry->compress_type = compress_type;
 205         entry->truncated_len = (u64)-1;
 206         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 207                 set_bit(type, &entry->flags);
 208
 209         if (dio)
 210                 set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 211
 212         /* one ref for the tree */
 213         atomic_set(&entry->refs, 1);
 214         init_waitqueue_head(&entry->wait);
 215         INIT_LIST_HEAD(&entry->list);
 216         INIT_LIST_HEAD(&entry->root_extent_list);
 217         INIT_LIST_HEAD(&entry->work_list);
 218         init_completion(&entry->completion);
 219         INIT_LIST_HEAD(&entry->log_list);
 220         INIT_LIST_HEAD(&entry->trans_list);
 221
 222         trace_btrfs_ordered_extent_add(inode, entry);
 223
 224         spin_lock_irq(&tree->lock);
 225         node = tree_insert(&tree->tree, file_offset,
 226                            &entry->rb_node);
 227         if (node)
 228                 ordered_data_tree_panic(inode, -EEXIST, file_offset);
 229         spin_unlock_irq(&tree->lock);
 230
 231         spin_lock(&root->ordered_extent_lock);
 232         list_add_tail(&entry->root_extent_list,
 233                       &root->ordered_extents);
 234         root->nr_ordered_extents++;
 235         if (root->nr_ordered_extents == 1) {
 236                 spin_lock(&root->fs_info->ordered_root_lock);
 237                 BUG_ON(!list_empty(&root->ordered_root));
 238                 list_add_tail(&root->ordered_root,
 239                               &root->fs_info->ordered_roots);
 240                 spin_unlock(&root->fs_info->ordered_root_lock);
 241         }
 242         spin_unlock(&root->ordered_extent_lock);
 243
 244         return 0;
 245 }
 246
 247 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 248                              u64 start, u64 len, u64 disk_len, int type)
 249 {
 250         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 251                                           disk_len, type, 0,
 252                                           BTRFS_COMPRESS_NONE);
 253 }
 254
 255 int btrfs_add_ordered_extent_dio(struct inode *inode, u64 file_offset,
 256                                  u64 start, u64 len, u64 disk_len, int type)
 257 {
 258         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 259                                           disk_len, type, 1,
 260                                           BTRFS_COMPRESS_NONE);
 261 }
 262
 263 int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
 264                                       u64 start, u64 len, u64 disk_len,
 265                                       int type, int compress_type)
 266 {
 267         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 268                                           disk_len, type, 0,
 269                                           compress_type);
 270 }
 271
 272 /*
 273  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 274  * when an ordered extent is finished.  If the list covers more than one
 275  * ordered extent, it is split across multiples.
 276  */
 277 void btrfs_add_ordered_sum(struct inode *inode,
 278                            struct btrfs_ordered_extent *entry,
 279                            struct btrfs_ordered_sum *sum)
 280 {
 281         struct btrfs_ordered_inode_tree *tree;
 282
 283         tree = &BTRFS_I(inode)->ordered_tree;
 284         spin_lock_irq(&tree->lock);
 285         list_add_tail(&sum->list, &entry->list);
 286         spin_unlock_irq(&tree->lock);
 287 }
 288
 289 /*
 290  * this is used to account for finished IO across a given range
 291  * of the file.  The IO may span ordered extents.  If
 292  * a given ordered_extent is completely done, 1 is returned, otherwise
 293  * 0.
 294  *
 295  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 296  * to make sure this function only returns 1 once for a given ordered extent.
 297  *
 298  * file_offset is updated to one byte past the range that is recorded as
 299  * complete.  This allows you to walk forward in the file.
 300  */
 301 int btrfs_dec_test_first_ordered_pending(struct inode *inode,
 302                                    struct btrfs_ordered_extent **cached,
 303                                    u64 *file_offset, u64 io_size, int uptodate)
 304 {
 305         struct btrfs_ordered_inode_tree *tree;
 306         struct rb_node *node;
 307         struct btrfs_ordered_extent *entry = NULL;
 308         int ret;
 309         unsigned long flags;
 310         u64 dec_end;
 311         u64 dec_start;
 312         u64 to_dec;
 313
 314         tree = &BTRFS_I(inode)->ordered_tree;
 315         spin_lock_irqsave(&tree->lock, flags);
 316         node = tree_search(tree, *file_offset);
 317         if (!node) {
 318                 ret = 1;
 319                 goto out;
 320         }
 321
 322         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 323         if (!offset_in_entry(entry, *file_offset)) {
 324                 ret = 1;
 325                 goto out;
 326         }
 327
 328         dec_start = max(*file_offset, entry->file_offset);
 329         dec_end = min(*file_offset + io_size, entry->file_offset +
 330                       entry->len);
 331         *file_offset = dec_end;
 332         if (dec_start > dec_end) {
 333                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 334                         "bad ordering dec_start %llu end %llu", dec_start, dec_end);
 335         }
 336         to_dec = dec_end - dec_start;
 337         if (to_dec > entry->bytes_left) {
 338                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 339                         "bad ordered accounting left %llu size %llu",
 340                         entry->bytes_left, to_dec);
 341         }
 342         entry->bytes_left -= to_dec;
 343         if (!uptodate)
 344                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 345
 346         if (entry->bytes_left == 0) {
 347                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 348                 if (waitqueue_active(&entry->wait))
 349                         wake_up(&entry->wait);
 350         } else {
 351                 ret = 1;
 352         }
 353 out:
 354         if (!ret && cached && entry) {
 355                 *cached = entry;
 356                 atomic_inc(&entry->refs);
 357         }
 358         spin_unlock_irqrestore(&tree->lock, flags);
 359         return ret == 0;
 360 }
 361
 362 /*
 363  * this is used to account for finished IO across a given range
 364  * of the file.  The IO should not span ordered extents.  If
 365  * a given ordered_extent is completely done, 1 is returned, otherwise
 366  * 0.
 367  *
 368  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 369  * to make sure this function only returns 1 once for a given ordered extent.
 370  */
 371 int btrfs_dec_test_ordered_pending(struct inode *inode,
 372                                    struct btrfs_ordered_extent **cached,
 373                                    u64 file_offset, u64 io_size, int uptodate)
 374 {
 375         struct btrfs_ordered_inode_tree *tree;
 376         struct rb_node *node;
 377         struct btrfs_ordered_extent *entry = NULL;
 378         unsigned long flags;
 379         int ret;
 380
 381         tree = &BTRFS_I(inode)->ordered_tree;
 382         spin_lock_irqsave(&tree->lock, flags);
 383         if (cached && *cached) {
 384                 entry = *cached;
 385                 goto have_entry;
 386         }
 387
 388         node = tree_search(tree, file_offset);
 389         if (!node) {
 390                 ret = 1;
 391                 goto out;
 392         }
 393
 394         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 395 have_entry:
 396         if (!offset_in_entry(entry, file_offset)) {
 397                 ret = 1;
 398                 goto out;
 399         }
 400
 401         if (io_size > entry->bytes_left) {
 402                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 403                            "bad ordered accounting left %llu size %llu",
 404                        entry->bytes_left, io_size);
 405         }
 406         entry->bytes_left -= io_size;
 407         if (!uptodate)
 408                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 409
 410         if (entry->bytes_left == 0) {
 411                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 412                 if (waitqueue_active(&entry->wait))
 413                         wake_up(&entry->wait);
 414         } else {
 415                 ret = 1;
 416         }
 417 out:
 418         if (!ret && cached && entry) {
 419                 *cached = entry;
 420                 atomic_inc(&entry->refs);
 421         }
 422         spin_unlock_irqrestore(&tree->lock, flags);
 423         return ret == 0;
 424 }
 425
 426 /* Needs to either be called under a log transaction or the log_mutex */
 427 void btrfs_get_logged_extents(struct inode *inode,
 428                               struct list_head *logged_list,
 429                               const loff_t start,
 430                               const loff_t end)
 431 {
 432         struct btrfs_ordered_inode_tree *tree;
 433         struct btrfs_ordered_extent *ordered;
 434         struct rb_node *n;
 435         struct rb_node *prev;
 436
 437         tree = &BTRFS_I(inode)->ordered_tree;
 438         spin_lock_irq(&tree->lock);
 439         n = __tree_search(&tree->tree, end, &prev);
 440         if (!n)
 441                 n = prev;
 442         for (; n; n = rb_prev(n)) {
 443                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 444                 if (ordered->file_offset > end)
 445                         continue;
 446                 if (entry_end(ordered) <= start)
 447                         break;
 448                 if (test_and_set_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
 449                         continue;
 450                 list_add(&ordered->log_list, logged_list);
 451                 atomic_inc(&ordered->refs);
 452         }
 453         spin_unlock_irq(&tree->lock);
 454 }
 455
 456 void btrfs_put_logged_extents(struct list_head *logged_list)
 457 {
 458         struct btrfs_ordered_extent *ordered;
 459
 460         while (!list_empty(logged_list)) {
 461                 ordered = list_first_entry(logged_list,
 462                                            struct btrfs_ordered_extent,
 463                                            log_list);
 464                 list_del_init(&ordered->log_list);
 465                 btrfs_put_ordered_extent(ordered);
 466         }
 467 }
 468
 469 void btrfs_submit_logged_extents(struct list_head *logged_list,
 470                                  struct btrfs_root *log)
 471 {
 472         int index = log->log_transid % 2;
 473
 474         spin_lock_irq(&log->log_extents_lock[index]);
 475         list_splice_tail(logged_list, &log->logged_list[index]);
 476         spin_unlock_irq(&log->log_extents_lock[index]);
 477 }
 478
 479 void btrfs_wait_logged_extents(struct btrfs_trans_handle *trans,
 480                                struct btrfs_root *log, u64 transid)
 481 {
 482         struct btrfs_ordered_extent *ordered;
 483         int index = transid % 2;
 484
 485         spin_lock_irq(&log->log_extents_lock[index]);
 486         while (!list_empty(&log->logged_list[index])) {
 487                 ordered = list_first_entry(&log->logged_list[index],
 488                                            struct btrfs_ordered_extent,
 489                                            log_list);
 490                 list_del_init(&ordered->log_list);
 491                 spin_unlock_irq(&log->log_extents_lock[index]);
 492
 493                 if (!test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags) &&
 494                     !test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags)) {
 495                         struct inode *inode = ordered->inode;
 496                         u64 start = ordered->file_offset;
 497                         u64 end = ordered->file_offset + ordered->len - 1;
 498
 499                         WARN_ON(!inode);
 500                         filemap_fdatawrite_range(inode->i_mapping, start, end);
 501                 }
 502                 wait_event(ordered->wait, test_bit(BTRFS_ORDERED_IO_DONE,
 503                                                    &ordered->flags));
 504
 505                 /*
 506                  * If our ordered extent completed it means it updated the
 507                  * fs/subvol and csum trees already, so no need to make the
 508                  * current transaction's commit wait for it, as we end up
 509                  * holding memory unnecessarily and delaying the inode's iput
 510                  * until the transaction commit (we schedule an iput for the
 511                  * inode when the ordered extent's refcount drops to 0), which
 512                  * prevents it from being evictable until the transaction
 513                  * commits.
 514                  */
 515                 if (test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags))
 516                         btrfs_put_ordered_extent(ordered);
 517                 else
 518                         list_add_tail(&ordered->trans_list, &trans->ordered);
 519
 520                 spin_lock_irq(&log->log_extents_lock[index]);
 521         }
 522         spin_unlock_irq(&log->log_extents_lock[index]);
 523 }
 524
 525 void btrfs_free_logged_extents(struct btrfs_root *log, u64 transid)
 526 {
 527         struct btrfs_ordered_extent *ordered;
 528         int index = transid % 2;
 529
 530         spin_lock_irq(&log->log_extents_lock[index]);
 531         while (!list_empty(&log->logged_list[index])) {
 532                 ordered = list_first_entry(&log->logged_list[index],
 533                                            struct btrfs_ordered_extent,
 534                                            log_list);
 535                 list_del_init(&ordered->log_list);
 536                 spin_unlock_irq(&log->log_extents_lock[index]);
 537                 btrfs_put_ordered_extent(ordered);
 538                 spin_lock_irq(&log->log_extents_lock[index]);
 539         }
 540         spin_unlock_irq(&log->log_extents_lock[index]);
 541 }
 542
 543 /*
 544  * used to drop a reference on an ordered extent.  This will free
 545  * the extent if the last reference is dropped
 546  */
 547 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 548 {
 549         struct list_head *cur;
 550         struct btrfs_ordered_sum *sum;
 551
 552         trace_btrfs_ordered_extent_put(entry->inode, entry);
 553
 554         if (atomic_dec_and_test(&entry->refs)) {
 555                 ASSERT(list_empty(&entry->log_list));
 556                 ASSERT(list_empty(&entry->trans_list));
 557                 ASSERT(list_empty(&entry->root_extent_list));
 558                 ASSERT(RB_EMPTY_NODE(&entry->rb_node));
 559                 if (entry->inode)
 560                         btrfs_add_delayed_iput(entry->inode);
 561                 while (!list_empty(&entry->list)) {
 562                         cur = entry->list.next;
 563                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 564                         list_del(&sum->list);
 565                         kfree(sum);
 566                 }
 567                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 568         }
 569 }
 570
 571 /*
 572  * remove an ordered extent from the tree.  No references are dropped
 573  * and waiters are woken up.
 574  */
 575 void btrfs_remove_ordered_extent(struct inode *inode,
 576                                  struct btrfs_ordered_extent *entry)
 577 {
 578         struct btrfs_ordered_inode_tree *tree;
 579         struct btrfs_root *root = BTRFS_I(inode)->root;
 580         struct rb_node *node;
 581
 582         tree = &BTRFS_I(inode)->ordered_tree;
 583         spin_lock_irq(&tree->lock);
 584         node = &entry->rb_node;
 585         rb_erase(node, &tree->tree);
 586         RB_CLEAR_NODE(node);
 587         if (tree->last == node)
 588                 tree->last = NULL;
 589         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 590         spin_unlock_irq(&tree->lock);
 591
 592         spin_lock(&root->ordered_extent_lock);
 593         list_del_init(&entry->root_extent_list);
 594         root->nr_ordered_extents--;
 595
 596         trace_btrfs_ordered_extent_remove(inode, entry);
 597
 598         if (!root->nr_ordered_extents) {
 599                 spin_lock(&root->fs_info->ordered_root_lock);
 600                 BUG_ON(list_empty(&root->ordered_root));
 601                 list_del_init(&root->ordered_root);
 602                 spin_unlock(&root->fs_info->ordered_root_lock);
 603         }
 604         spin_unlock(&root->ordered_extent_lock);
 605         wake_up(&entry->wait);
 606 }
 607
 608 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 609 {
 610         struct btrfs_ordered_extent *ordered;
 611
 612         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 613         btrfs_start_ordered_extent(ordered->inode, ordered, 1);
 614         complete(&ordered->completion);
 615 }
 616
 617 /*
 618  * wait for all the ordered extents in a root.  This is done when balancing
 619  * space between drives.
 620  */
 621 int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)
 622 {
 623         struct list_head splice, works;
 624         struct btrfs_ordered_extent *ordered, *next;
 625         int count = 0;
 626
 627         INIT_LIST_HEAD(&splice);
 628         INIT_LIST_HEAD(&works);
 629
 630         mutex_lock(&root->ordered_extent_mutex);
 631         spin_lock(&root->ordered_extent_lock);
 632         list_splice_init(&root->ordered_extents, &splice);
 633         while (!list_empty(&splice) && nr) {
 634                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 635                                            root_extent_list);
 636                 list_move_tail(&ordered->root_extent_list,
 637                                &root->ordered_extents);
 638                 atomic_inc(&ordered->refs);
 639                 spin_unlock(&root->ordered_extent_lock);
 640
 641                 btrfs_init_work(&ordered->flush_work,
 642                                 btrfs_flush_delalloc_helper,
 643                                 btrfs_run_ordered_extent_work, NULL, NULL);
 644                 list_add_tail(&ordered->work_list, &works);
 645                 btrfs_queue_work(root->fs_info->flush_workers,
 646                                  &ordered->flush_work);
 647
 648                 cond_resched();
 649                 spin_lock(&root->ordered_extent_lock);
 650                 if (nr != -1)
 651                         nr--;
 652                 count++;
 653         }
 654         list_splice_tail(&splice, &root->ordered_extents);
 655         spin_unlock(&root->ordered_extent_lock);
 656
 657         list_for_each_entry_safe(ordered, next, &works, work_list) {
 658                 list_del_init(&ordered->work_list);
 659                 wait_for_completion(&ordered->completion);
 660                 btrfs_put_ordered_extent(ordered);
 661                 cond_resched();
 662         }
 663         mutex_unlock(&root->ordered_extent_mutex);
 664
 665         return count;
 666 }
 667
 668 void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr)
 669 {
 670         struct btrfs_root *root;
 671         struct list_head splice;
 672         int done;
 673
 674         INIT_LIST_HEAD(&splice);
 675
 676         mutex_lock(&fs_info->ordered_operations_mutex);
 677         spin_lock(&fs_info->ordered_root_lock);
 678         list_splice_init(&fs_info->ordered_roots, &splice);
 679         while (!list_empty(&splice) && nr) {
 680                 root = list_first_entry(&splice, struct btrfs_root,
 681                                         ordered_root);
 682                 root = btrfs_grab_fs_root(root);
 683                 BUG_ON(!root);
 684                 list_move_tail(&root->ordered_root,
 685                                &fs_info->ordered_roots);
 686                 spin_unlock(&fs_info->ordered_root_lock);
 687
 688                 done = btrfs_wait_ordered_extents(root, nr);
 689                 btrfs_put_fs_root(root);
 690
 691                 spin_lock(&fs_info->ordered_root_lock);
 692                 if (nr != -1) {
 693                         nr -= done;
 694                         WARN_ON(nr < 0);
 695                 }
 696         }
 697         list_splice_tail(&splice, &fs_info->ordered_roots);
 698         spin_unlock(&fs_info->ordered_root_lock);
 699         mutex_unlock(&fs_info->ordered_operations_mutex);
 700 }
 701
 702 /*
 703  * Used to start IO or wait for a given ordered extent to finish.
 704  *
 705  * If wait is one, this effectively waits on page writeback for all the pages
 706  * in the extent, and it waits on the io completion code to insert
 707  * metadata into the btree corresponding to the extent
 708  */
 709 void btrfs_start_ordered_extent(struct inode *inode,
 710                                        struct btrfs_ordered_extent *entry,
 711                                        int wait)
 712 {
 713         u64 start = entry->file_offset;
 714         u64 end = start + entry->len - 1;
 715
 716         trace_btrfs_ordered_extent_start(inode, entry);
 717
 718         /*
 719          * pages in the range can be dirty, clean or writeback.  We
 720          * start IO on any dirty ones so the wait doesn't stall waiting
 721          * for the flusher thread to find them
 722          */
 723         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 724                 filemap_fdatawrite_range(inode->i_mapping, start, end);
 725         if (wait) {
 726                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 727                                                  &entry->flags));
 728         }
 729 }
 730
 731 /*
 732  * Used to wait on ordered extents across a large range of bytes.
 733  */
 734 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 735 {
 736         int ret = 0;
 737         int ret_wb = 0;
 738         u64 end;
 739         u64 orig_end;
 740         struct btrfs_ordered_extent *ordered;
 741
 742         if (start + len < start) {
 743                 orig_end = INT_LIMIT(loff_t);
 744         } else {
 745                 orig_end = start + len - 1;
 746                 if (orig_end > INT_LIMIT(loff_t))
 747                         orig_end = INT_LIMIT(loff_t);
 748         }
 749
 750         /* start IO across the range first to instantiate any delalloc
 751          * extents
 752          */
 753         ret = btrfs_fdatawrite_range(inode, start, orig_end);
 754         if (ret)
 755                 return ret;
 756
 757         /*
 758          * If we have a writeback error don't return immediately. Wait first
 759          * for any ordered extents that haven't completed yet. This is to make
 760          * sure no one can dirty the same page ranges and call writepages()
 761          * before the ordered extents complete - to avoid failures (-EEXIST)
 762          * when adding the new ordered extents to the ordered tree.
 763          */
 764         ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 765
 766         end = orig_end;
 767         while (1) {
 768                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
 769                 if (!ordered)
 770                         break;
 771                 if (ordered->file_offset > orig_end) {
 772                         btrfs_put_ordered_extent(ordered);
 773                         break;
 774                 }
 775                 if (ordered->file_offset + ordered->len <= start) {
 776                         btrfs_put_ordered_extent(ordered);
 777                         break;
 778                 }
 779                 btrfs_start_ordered_extent(inode, ordered, 1);
 780                 end = ordered->file_offset;
 781                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 782                         ret = -EIO;
 783                 btrfs_put_ordered_extent(ordered);
 784                 if (ret || end == 0 || end == start)
 785                         break;
 786                 end--;
 787         }
 788         return ret_wb ? ret_wb : ret;
 789 }
 790
 791 /*
 792  * find an ordered extent corresponding to file_offset.  return NULL if
 793  * nothing is found, otherwise take a reference on the extent and return it
 794  */
 795 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 796                                                          u64 file_offset)
 797 {
 798         struct btrfs_ordered_inode_tree *tree;
 799         struct rb_node *node;
 800         struct btrfs_ordered_extent *entry = NULL;
 801
 802         tree = &BTRFS_I(inode)->ordered_tree;
 803         spin_lock_irq(&tree->lock);
 804         node = tree_search(tree, file_offset);
 805         if (!node)
 806                 goto out;
 807
 808         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 809         if (!offset_in_entry(entry, file_offset))
 810                 entry = NULL;
 811         if (entry)
 812                 atomic_inc(&entry->refs);
 813 out:
 814         spin_unlock_irq(&tree->lock);
 815         return entry;
 816 }
 817
 818 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 819  * extents that exist in the range, rather than just the start of the range.
 820  */
 821 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(struct inode *inode,
 822                                                         u64 file_offset,
 823                                                         u64 len)
 824 {
 825         struct btrfs_ordered_inode_tree *tree;
 826         struct rb_node *node;
 827         struct btrfs_ordered_extent *entry = NULL;
 828
 829         tree = &BTRFS_I(inode)->ordered_tree;
 830         spin_lock_irq(&tree->lock);
 831         node = tree_search(tree, file_offset);
 832         if (!node) {
 833                 node = tree_search(tree, file_offset + len);
 834                 if (!node)
 835                         goto out;
 836         }
 837
 838         while (1) {
 839                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 840                 if (range_overlaps(entry, file_offset, len))
 841                         break;
 842
 843                 if (entry->file_offset >= file_offset + len) {
 844                         entry = NULL;
 845                         break;
 846                 }
 847                 entry = NULL;
 848                 node = rb_next(node);
 849                 if (!node)
 850                         break;
 851         }
 852 out:
 853         if (entry)
 854                 atomic_inc(&entry->refs);
 855         spin_unlock_irq(&tree->lock);
 856         return entry;
 857 }
 858
 859 bool btrfs_have_ordered_extents_in_range(struct inode *inode,
 860                                          u64 file_offset,
 861                                          u64 len)
 862 {
 863         struct btrfs_ordered_extent *oe;
 864
 865         oe = btrfs_lookup_ordered_range(inode, file_offset, len);
 866         if (oe) {
 867                 btrfs_put_ordered_extent(oe);
 868                 return true;
 869         }
 870         return false;
 871 }
 872
 873 /*
 874  * lookup and return any extent before 'file_offset'.  NULL is returned
 875  * if none is found
 876  */
 877 struct btrfs_ordered_extent *
 878 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 879 {
 880         struct btrfs_ordered_inode_tree *tree;
 881         struct rb_node *node;
 882         struct btrfs_ordered_extent *entry = NULL;
 883
 884         tree = &BTRFS_I(inode)->ordered_tree;
 885         spin_lock_irq(&tree->lock);
 886         node = tree_search(tree, file_offset);
 887         if (!node)
 888                 goto out;
 889
 890         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 891         atomic_inc(&entry->refs);
 892 out:
 893         spin_unlock_irq(&tree->lock);
 894         return entry;
 895 }
 896
 897 /*
 898  * After an extent is done, call this to conditionally update the on disk
 899  * i_size.  i_size is updated to cover any fully written part of the file.
 900  */
 901 int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 902                                 struct btrfs_ordered_extent *ordered)
 903 {
 904         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 905         u64 disk_i_size;
 906         u64 new_i_size;
 907         u64 i_size = i_size_read(inode);
 908         struct rb_node *node;
 909         struct rb_node *prev = NULL;
 910         struct btrfs_ordered_extent *test;
 911         int ret = 1;
 912
 913         spin_lock_irq(&tree->lock);
 914         if (ordered) {
 915                 offset = entry_end(ordered);
 916                 if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags))
 917                         offset = min(offset,
 918                                      ordered->file_offset +
 919                                      ordered->truncated_len);
 920         } else {
 921                 offset = ALIGN(offset, BTRFS_I(inode)->root->sectorsize);
 922         }
 923         disk_i_size = BTRFS_I(inode)->disk_i_size;
 924
 925         /* truncate file */
 926         if (disk_i_size > i_size) {
 927                 BTRFS_I(inode)->disk_i_size = i_size;
 928                 ret = 0;
 929                 goto out;
 930         }
 931
 932         /*
 933          * if the disk i_size is already at the inode->i_size, or
 934          * this ordered extent is inside the disk i_size, we're done
 935          */
 936         if (disk_i_size == i_size)
 937                 goto out;
 938
 939         /*
 940          * We still need to update disk_i_size if outstanding_isize is greater
 941          * than disk_i_size.
 942          */
 943         if (offset <= disk_i_size &&
 944             (!ordered || ordered->outstanding_isize <= disk_i_size))
 945                 goto out;
 946
 947         /*
 948          * walk backward from this ordered extent to disk_i_size.
 949          * if we find an ordered extent then we can't update disk i_size
 950          * yet
 951          */
 952         if (ordered) {
 953                 node = rb_prev(&ordered->rb_node);
 954         } else {
 955                 prev = tree_search(tree, offset);
 956                 /*
 957                  * we insert file extents without involving ordered struct,
 958                  * so there should be no ordered struct cover this offset
 959                  */
 960                 if (prev) {
 961                         test = rb_entry(prev, struct btrfs_ordered_extent,
 962                                         rb_node);
 963                         BUG_ON(offset_in_entry(test, offset));
 964                 }
 965                 node = prev;
 966         }
 967         for (; node; node = rb_prev(node)) {
 968                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 969
 970                 /* We treat this entry as if it doesnt exist */
 971                 if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
 972                         continue;
 973                 if (test->file_offset + test->len <= disk_i_size)
 974                         break;
 975                 if (test->file_offset >= i_size)
 976                         break;
 977                 if (entry_end(test) > disk_i_size) {
 978                         /*
 979                          * we don't update disk_i_size now, so record this
 980                          * undealt i_size. Or we will not know the real
 981                          * i_size.
 982                          */
 983                         if (test->outstanding_isize < offset)
 984                                 test->outstanding_isize = offset;
 985                         if (ordered &&
 986                             ordered->outstanding_isize >
 987                             test->outstanding_isize)
 988                                 test->outstanding_isize =
 989                                                 ordered->outstanding_isize;
 990                         goto out;
 991                 }
 992         }
 993         new_i_size = min_t(u64, offset, i_size);
 994
 995         /*
 996          * Some ordered extents may completed before the current one, and
 997          * we hold the real i_size in ->outstanding_isize.
 998          */
 999         if (ordered && ordered->outstanding_isize > new_i_size)
1000                 new_i_size = min_t(u64, ordered->outstanding_isize, i_size);
1001         BTRFS_I(inode)->disk_i_size = new_i_size;
1002         ret = 0;
1003 out:
1004         /*
1005          * We need to do this because we can't remove ordered extents until
1006          * after the i_disk_size has been updated and then the inode has been
1007          * updated to reflect the change, so we need to tell anybody who finds
1008          * this ordered extent that we've already done all the real work, we
1009          * just haven't completed all the other work.
1010          */
1011         if (ordered)
1012                 set_bit(BTRFS_ORDERED_UPDATED_ISIZE, &ordered->flags);
1013         spin_unlock_irq(&tree->lock);
1014         return ret;
1015 }
1016
1017 /*
1018  * search the ordered extents for one corresponding to 'offset' and
1019  * try to find a checksum.  This is used because we allow pages to
1020  * be reclaimed before their checksum is actually put into the btree
1021  */
1022 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
1023                            u32 *sum, int len)
1024 {
1025         struct btrfs_ordered_sum *ordered_sum;
1026         struct btrfs_ordered_extent *ordered;
1027         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
1028         unsigned long num_sectors;
1029         unsigned long i;
1030         u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
1031         int index = 0;
1032
1033         ordered = btrfs_lookup_ordered_extent(inode, offset);
1034         if (!ordered)
1035                 return 0;
1036
1037         spin_lock_irq(&tree->lock);
1038         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
1039                 if (disk_bytenr >= ordered_sum->bytenr &&
1040                     disk_bytenr < ordered_sum->bytenr + ordered_sum->len) {
1041                         i = (disk_bytenr - ordered_sum->bytenr) >>
1042                             inode->i_sb->s_blocksize_bits;
1043                         num_sectors = ordered_sum->len >>
1044                                       inode->i_sb->s_blocksize_bits;
1045                         num_sectors = min_t(int, len - index, num_sectors - i);
1046                         memcpy(sum + index, ordered_sum->sums + i,
1047                                num_sectors);
1048
1049                         index += (int)num_sectors;
1050                         if (index == len)
1051                                 goto out;
1052                         disk_bytenr += num_sectors * sectorsize;
1053                 }
1054         }
1055 out:
1056         spin_unlock_irq(&tree->lock);
1057         btrfs_put_ordered_extent(ordered);
1058         return index;
1059 }
1060
1061 int __init ordered_data_init(void)
1062 {
1063         btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
1064                                      sizeof(struct btrfs_ordered_extent), 0,
1065                                      SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
1066                                      NULL);
1067         if (!btrfs_ordered_extent_cache)
1068                 return -ENOMEM;
1069
1070         return 0;
1071 }
1072
1073 void ordered_data_exit(void)
1074 {
1075         if (btrfs_ordered_extent_cache)
1076                 kmem_cache_destroy(btrfs_ordered_extent_cache);
1077 }