fs/btrfs/ordered-data.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/slab.h>
   7 #include <linux/blkdev.h>
   8 #include <linux/writeback.h>
   9 #include <linux/sched/mm.h>
  10 #include "messages.h"
  11 #include "misc.h"
  12 #include "ctree.h"
  13 #include "transaction.h"
  14 #include "btrfs_inode.h"
  15 #include "extent_io.h"
  16 #include "disk-io.h"
  17 #include "compression.h"
  18 #include "delalloc-space.h"
  19 #include "qgroup.h"
  20 #include "subpage.h"
  21 #include "file.h"
  22
  23 static struct kmem_cache *btrfs_ordered_extent_cache;
  24
  25 static u64 entry_end(struct btrfs_ordered_extent *entry)
  26 {
  27         if (entry->file_offset + entry->num_bytes < entry->file_offset)
  28                 return (u64)-1;
  29         return entry->file_offset + entry->num_bytes;
  30 }
  31
  32 /* returns NULL if the insertion worked, or it returns the node it did find
  33  * in the tree
  34  */
  35 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  36                                    struct rb_node *node)
  37 {
  38         struct rb_node **p = &root->rb_node;
  39         struct rb_node *parent = NULL;
  40         struct btrfs_ordered_extent *entry;
  41
  42         while (*p) {
  43                 parent = *p;
  44                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  45
  46                 if (file_offset < entry->file_offset)
  47                         p = &(*p)->rb_left;
  48                 else if (file_offset >= entry_end(entry))
  49                         p = &(*p)->rb_right;
  50                 else
  51                         return parent;
  52         }
  53
  54         rb_link_node(node, parent, p);
  55         rb_insert_color(node, root);
  56         return NULL;
  57 }
  58
  59 /*
  60  * look for a given offset in the tree, and if it can't be found return the
  61  * first lesser offset
  62  */
  63 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  64                                      struct rb_node **prev_ret)
  65 {
  66         struct rb_node *n = root->rb_node;
  67         struct rb_node *prev = NULL;
  68         struct rb_node *test;
  69         struct btrfs_ordered_extent *entry;
  70         struct btrfs_ordered_extent *prev_entry = NULL;
  71
  72         while (n) {
  73                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  74                 prev = n;
  75                 prev_entry = entry;
  76
  77                 if (file_offset < entry->file_offset)
  78                         n = n->rb_left;
  79                 else if (file_offset >= entry_end(entry))
  80                         n = n->rb_right;
  81                 else
  82                         return n;
  83         }
  84         if (!prev_ret)
  85                 return NULL;
  86
  87         while (prev && file_offset >= entry_end(prev_entry)) {
  88                 test = rb_next(prev);
  89                 if (!test)
  90                         break;
  91                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
  92                                       rb_node);
  93                 if (file_offset < entry_end(prev_entry))
  94                         break;
  95
  96                 prev = test;
  97         }
  98         if (prev)
  99                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 100                                       rb_node);
 101         while (prev && file_offset < entry_end(prev_entry)) {
 102                 test = rb_prev(prev);
 103                 if (!test)
 104                         break;
 105                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 106                                       rb_node);
 107                 prev = test;
 108         }
 109         *prev_ret = prev;
 110         return NULL;
 111 }
 112
 113 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 114                           u64 len)
 115 {
 116         if (file_offset + len <= entry->file_offset ||
 117             entry->file_offset + entry->num_bytes <= file_offset)
 118                 return 0;
 119         return 1;
 120 }
 121
 122 /*
 123  * look find the first ordered struct that has this offset, otherwise
 124  * the first one less than this offset
 125  */
 126 static inline struct rb_node *ordered_tree_search(struct btrfs_inode *inode,
 127                                                   u64 file_offset)
 128 {
 129         struct rb_node *prev = NULL;
 130         struct rb_node *ret;
 131         struct btrfs_ordered_extent *entry;
 132
 133         if (inode->ordered_tree_last) {
 134                 entry = rb_entry(inode->ordered_tree_last, struct btrfs_ordered_extent,
 135                                  rb_node);
 136                 if (in_range(file_offset, entry->file_offset, entry->num_bytes))
 137                         return inode->ordered_tree_last;
 138         }
 139         ret = __tree_search(&inode->ordered_tree, file_offset, &prev);
 140         if (!ret)
 141                 ret = prev;
 142         if (ret)
 143                 inode->ordered_tree_last = ret;
 144         return ret;
 145 }
 146
 147 static struct btrfs_ordered_extent *alloc_ordered_extent(
 148                         struct btrfs_inode *inode, u64 file_offset, u64 num_bytes,
 149                         u64 ram_bytes, u64 disk_bytenr, u64 disk_num_bytes,
 150                         u64 offset, unsigned long flags, int compress_type)
 151 {
 152         struct btrfs_ordered_extent *entry;
 153         int ret;
 154         u64 qgroup_rsv = 0;
 155
 156         if (flags &
 157             ((1 << BTRFS_ORDERED_NOCOW) | (1 << BTRFS_ORDERED_PREALLOC))) {
 158                 /* For nocow write, we can release the qgroup rsv right now */
 159                 ret = btrfs_qgroup_free_data(inode, NULL, file_offset, num_bytes, &qgroup_rsv);
 160                 if (ret < 0)
 161                         return ERR_PTR(ret);
 162         } else {
 163                 /*
 164                  * The ordered extent has reserved qgroup space, release now
 165                  * and pass the reserved number for qgroup_record to free.
 166                  */
 167                 ret = btrfs_qgroup_release_data(inode, file_offset, num_bytes, &qgroup_rsv);
 168                 if (ret < 0)
 169                         return ERR_PTR(ret);
 170         }
 171         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 172         if (!entry)
 173                 return ERR_PTR(-ENOMEM);
 174
 175         entry->file_offset = file_offset;
 176         entry->num_bytes = num_bytes;
 177         entry->ram_bytes = ram_bytes;
 178         entry->disk_bytenr = disk_bytenr;
 179         entry->disk_num_bytes = disk_num_bytes;
 180         entry->offset = offset;
 181         entry->bytes_left = num_bytes;
 182         entry->inode = igrab(&inode->vfs_inode);
 183         entry->compress_type = compress_type;
 184         entry->truncated_len = (u64)-1;
 185         entry->qgroup_rsv = qgroup_rsv;
 186         entry->flags = flags;
 187         refcount_set(&entry->refs, 1);
 188         init_waitqueue_head(&entry->wait);
 189         INIT_LIST_HEAD(&entry->list);
 190         INIT_LIST_HEAD(&entry->log_list);
 191         INIT_LIST_HEAD(&entry->root_extent_list);
 192         INIT_LIST_HEAD(&entry->work_list);
 193         INIT_LIST_HEAD(&entry->bioc_list);
 194         init_completion(&entry->completion);
 195
 196         /*
 197          * We don't need the count_max_extents here, we can assume that all of
 198          * that work has been done at higher layers, so this is truly the
 199          * smallest the extent is going to get.
 200          */
 201         spin_lock(&inode->lock);
 202         btrfs_mod_outstanding_extents(inode, 1);
 203         spin_unlock(&inode->lock);
 204
 205         return entry;
 206 }
 207
 208 static void insert_ordered_extent(struct btrfs_ordered_extent *entry)
 209 {
 210         struct btrfs_inode *inode = BTRFS_I(entry->inode);
 211         struct btrfs_root *root = inode->root;
 212         struct btrfs_fs_info *fs_info = root->fs_info;
 213         struct rb_node *node;
 214
 215         trace_btrfs_ordered_extent_add(inode, entry);
 216
 217         percpu_counter_add_batch(&fs_info->ordered_bytes, entry->num_bytes,
 218                                  fs_info->delalloc_batch);
 219
 220         /* One ref for the tree. */
 221         refcount_inc(&entry->refs);
 222
 223         spin_lock_irq(&inode->ordered_tree_lock);
 224         node = tree_insert(&inode->ordered_tree, entry->file_offset,
 225                            &entry->rb_node);
 226         if (node)
 227                 btrfs_panic(fs_info, -EEXIST,
 228                                 "inconsistency in ordered tree at offset %llu",
 229                                 entry->file_offset);
 230         spin_unlock_irq(&inode->ordered_tree_lock);
 231
 232         spin_lock(&root->ordered_extent_lock);
 233         list_add_tail(&entry->root_extent_list,
 234                       &root->ordered_extents);
 235         root->nr_ordered_extents++;
 236         if (root->nr_ordered_extents == 1) {
 237                 spin_lock(&fs_info->ordered_root_lock);
 238                 BUG_ON(!list_empty(&root->ordered_root));
 239                 list_add_tail(&root->ordered_root, &fs_info->ordered_roots);
 240                 spin_unlock(&fs_info->ordered_root_lock);
 241         }
 242         spin_unlock(&root->ordered_extent_lock);
 243 }
 244
 245 /*
 246  * Add an ordered extent to the per-inode tree.
 247  *
 248  * @inode:           Inode that this extent is for.
 249  * @file_offset:     Logical offset in file where the extent starts.
 250  * @num_bytes:       Logical length of extent in file.
 251  * @ram_bytes:       Full length of unencoded data.
 252  * @disk_bytenr:     Offset of extent on disk.
 253  * @disk_num_bytes:  Size of extent on disk.
 254  * @offset:          Offset into unencoded data where file data starts.
 255  * @flags:           Flags specifying type of extent (1 << BTRFS_ORDERED_*).
 256  * @compress_type:   Compression algorithm used for data.
 257  *
 258  * Most of these parameters correspond to &struct btrfs_file_extent_item. The
 259  * tree is given a single reference on the ordered extent that was inserted, and
 260  * the returned pointer is given a second reference.
 261  *
 262  * Return: the new ordered extent or error pointer.
 263  */
 264 struct btrfs_ordered_extent *btrfs_alloc_ordered_extent(
 265                         struct btrfs_inode *inode, u64 file_offset,
 266                         u64 num_bytes, u64 ram_bytes, u64 disk_bytenr,
 267                         u64 disk_num_bytes, u64 offset, unsigned long flags,
 268                         int compress_type)
 269 {
 270         struct btrfs_ordered_extent *entry;
 271
 272         ASSERT((flags & ~BTRFS_ORDERED_TYPE_FLAGS) == 0);
 273
 274         entry = alloc_ordered_extent(inode, file_offset, num_bytes, ram_bytes,
 275                                      disk_bytenr, disk_num_bytes, offset, flags,
 276                                      compress_type);
 277         if (!IS_ERR(entry))
 278                 insert_ordered_extent(entry);
 279         return entry;
 280 }
 281
 282 /*
 283  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 284  * when an ordered extent is finished.  If the list covers more than one
 285  * ordered extent, it is split across multiples.
 286  */
 287 void btrfs_add_ordered_sum(struct btrfs_ordered_extent *entry,
 288                            struct btrfs_ordered_sum *sum)
 289 {
 290         struct btrfs_inode *inode = BTRFS_I(entry->inode);
 291
 292         spin_lock_irq(&inode->ordered_tree_lock);
 293         list_add_tail(&sum->list, &entry->list);
 294         spin_unlock_irq(&inode->ordered_tree_lock);
 295 }
 296
 297 void btrfs_mark_ordered_extent_error(struct btrfs_ordered_extent *ordered)
 298 {
 299         if (!test_and_set_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 300                 mapping_set_error(ordered->inode->i_mapping, -EIO);
 301 }
 302
 303 static void finish_ordered_fn(struct btrfs_work *work)
 304 {
 305         struct btrfs_ordered_extent *ordered_extent;
 306
 307         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
 308         btrfs_finish_ordered_io(ordered_extent);
 309 }
 310
 311 static bool can_finish_ordered_extent(struct btrfs_ordered_extent *ordered,
 312                                       struct page *page, u64 file_offset,
 313                                       u64 len, bool uptodate)
 314 {
 315         struct btrfs_inode *inode = BTRFS_I(ordered->inode);
 316         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 317
 318         lockdep_assert_held(&inode->ordered_tree_lock);
 319
 320         if (page) {
 321                 ASSERT(page->mapping);
 322                 ASSERT(page_offset(page) <= file_offset);
 323                 ASSERT(file_offset + len <= page_offset(page) + PAGE_SIZE);
 324
 325                 /*
 326                  * Ordered (Private2) bit indicates whether we still have
 327                  * pending io unfinished for the ordered extent.
 328                  *
 329                  * If there's no such bit, we need to skip to next range.
 330                  */
 331                 if (!btrfs_folio_test_ordered(fs_info, page_folio(page),
 332                                               file_offset, len))
 333                         return false;
 334                 btrfs_folio_clear_ordered(fs_info, page_folio(page), file_offset, len);
 335         }
 336
 337         /* Now we're fine to update the accounting. */
 338         if (WARN_ON_ONCE(len > ordered->bytes_left)) {
 339                 btrfs_crit(fs_info,
 340 "bad ordered extent accounting, root=%llu ino=%llu OE offset=%llu OE len=%llu to_dec=%llu left=%llu",
 341                            btrfs_root_id(inode->root), btrfs_ino(inode),
 342                            ordered->file_offset, ordered->num_bytes,
 343                            len, ordered->bytes_left);
 344                 ordered->bytes_left = 0;
 345         } else {
 346                 ordered->bytes_left -= len;
 347         }
 348
 349         if (!uptodate)
 350                 set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
 351
 352         if (ordered->bytes_left)
 353                 return false;
 354
 355         /*
 356          * All the IO of the ordered extent is finished, we need to queue
 357          * the finish_func to be executed.
 358          */
 359         set_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags);
 360         cond_wake_up(&ordered->wait);
 361         refcount_inc(&ordered->refs);
 362         trace_btrfs_ordered_extent_mark_finished(inode, ordered);
 363         return true;
 364 }
 365
 366 static void btrfs_queue_ordered_fn(struct btrfs_ordered_extent *ordered)
 367 {
 368         struct btrfs_inode *inode = BTRFS_I(ordered->inode);
 369         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 370         struct btrfs_workqueue *wq = btrfs_is_free_space_inode(inode) ?
 371                 fs_info->endio_freespace_worker : fs_info->endio_write_workers;
 372
 373         btrfs_init_work(&ordered->work, finish_ordered_fn, NULL);
 374         btrfs_queue_work(wq, &ordered->work);
 375 }
 376
 377 bool btrfs_finish_ordered_extent(struct btrfs_ordered_extent *ordered,
 378                                  struct page *page, u64 file_offset, u64 len,
 379                                  bool uptodate)
 380 {
 381         struct btrfs_inode *inode = BTRFS_I(ordered->inode);
 382         unsigned long flags;
 383         bool ret;
 384
 385         trace_btrfs_finish_ordered_extent(inode, file_offset, len, uptodate);
 386
 387         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 388         ret = can_finish_ordered_extent(ordered, page, file_offset, len, uptodate);
 389         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 390
 391         if (ret)
 392                 btrfs_queue_ordered_fn(ordered);
 393         return ret;
 394 }
 395
 396 /*
 397  * Mark all ordered extents io inside the specified range finished.
 398  *
 399  * @page:        The involved page for the operation.
 400  *               For uncompressed buffered IO, the page status also needs to be
 401  *               updated to indicate whether the pending ordered io is finished.
 402  *               Can be NULL for direct IO and compressed write.
 403  *               For these cases, callers are ensured they won't execute the
 404  *               endio function twice.
 405  *
 406  * This function is called for endio, thus the range must have ordered
 407  * extent(s) covering it.
 408  */
 409 void btrfs_mark_ordered_io_finished(struct btrfs_inode *inode,
 410                                     struct page *page, u64 file_offset,
 411                                     u64 num_bytes, bool uptodate)
 412 {
 413         struct rb_node *node;
 414         struct btrfs_ordered_extent *entry = NULL;
 415         unsigned long flags;
 416         u64 cur = file_offset;
 417
 418         trace_btrfs_writepage_end_io_hook(inode, file_offset,
 419                                           file_offset + num_bytes - 1,
 420                                           uptodate);
 421
 422         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 423         while (cur < file_offset + num_bytes) {
 424                 u64 entry_end;
 425                 u64 end;
 426                 u32 len;
 427
 428                 node = ordered_tree_search(inode, cur);
 429                 /* No ordered extents at all */
 430                 if (!node)
 431                         break;
 432
 433                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 434                 entry_end = entry->file_offset + entry->num_bytes;
 435                 /*
 436                  * |<-- OE --->|  |
 437                  *                cur
 438                  * Go to next OE.
 439                  */
 440                 if (cur >= entry_end) {
 441                         node = rb_next(node);
 442                         /* No more ordered extents, exit */
 443                         if (!node)
 444                                 break;
 445                         entry = rb_entry(node, struct btrfs_ordered_extent,
 446                                          rb_node);
 447
 448                         /* Go to next ordered extent and continue */
 449                         cur = entry->file_offset;
 450                         continue;
 451                 }
 452                 /*
 453                  * |    |<--- OE --->|
 454                  * cur
 455                  * Go to the start of OE.
 456                  */
 457                 if (cur < entry->file_offset) {
 458                         cur = entry->file_offset;
 459                         continue;
 460                 }
 461
 462                 /*
 463                  * Now we are definitely inside one ordered extent.
 464                  *
 465                  * |<--- OE --->|
 466                  *      |
 467                  *      cur
 468                  */
 469                 end = min(entry->file_offset + entry->num_bytes,
 470                           file_offset + num_bytes) - 1;
 471                 ASSERT(end + 1 - cur < U32_MAX);
 472                 len = end + 1 - cur;
 473
 474                 if (can_finish_ordered_extent(entry, page, cur, len, uptodate)) {
 475                         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 476                         btrfs_queue_ordered_fn(entry);
 477                         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 478                 }
 479                 cur += len;
 480         }
 481         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 482 }
 483
 484 /*
 485  * Finish IO for one ordered extent across a given range.  The range can only
 486  * contain one ordered extent.
 487  *
 488  * @cached:      The cached ordered extent. If not NULL, we can skip the tree
 489  *               search and use the ordered extent directly.
 490  *               Will be also used to store the finished ordered extent.
 491  * @file_offset: File offset for the finished IO
 492  * @io_size:     Length of the finish IO range
 493  *
 494  * Return true if the ordered extent is finished in the range, and update
 495  * @cached.
 496  * Return false otherwise.
 497  *
 498  * NOTE: The range can NOT cross multiple ordered extents.
 499  * Thus caller should ensure the range doesn't cross ordered extents.
 500  */
 501 bool btrfs_dec_test_ordered_pending(struct btrfs_inode *inode,
 502                                     struct btrfs_ordered_extent **cached,
 503                                     u64 file_offset, u64 io_size)
 504 {
 505         struct rb_node *node;
 506         struct btrfs_ordered_extent *entry = NULL;
 507         unsigned long flags;
 508         bool finished = false;
 509
 510         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 511         if (cached && *cached) {
 512                 entry = *cached;
 513                 goto have_entry;
 514         }
 515
 516         node = ordered_tree_search(inode, file_offset);
 517         if (!node)
 518                 goto out;
 519
 520         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 521 have_entry:
 522         if (!in_range(file_offset, entry->file_offset, entry->num_bytes))
 523                 goto out;
 524
 525         if (io_size > entry->bytes_left)
 526                 btrfs_crit(inode->root->fs_info,
 527                            "bad ordered accounting left %llu size %llu",
 528                        entry->bytes_left, io_size);
 529
 530         entry->bytes_left -= io_size;
 531
 532         if (entry->bytes_left == 0) {
 533                 /*
 534                  * Ensure only one caller can set the flag and finished_ret
 535                  * accordingly
 536                  */
 537                 finished = !test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 538                 /* test_and_set_bit implies a barrier */
 539                 cond_wake_up_nomb(&entry->wait);
 540         }
 541 out:
 542         if (finished && cached && entry) {
 543                 *cached = entry;
 544                 refcount_inc(&entry->refs);
 545                 trace_btrfs_ordered_extent_dec_test_pending(inode, entry);
 546         }
 547         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 548         return finished;
 549 }
 550
 551 /*
 552  * used to drop a reference on an ordered extent.  This will free
 553  * the extent if the last reference is dropped
 554  */
 555 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 556 {
 557         struct list_head *cur;
 558         struct btrfs_ordered_sum *sum;
 559
 560         trace_btrfs_ordered_extent_put(BTRFS_I(entry->inode), entry);
 561
 562         if (refcount_dec_and_test(&entry->refs)) {
 563                 ASSERT(list_empty(&entry->root_extent_list));
 564                 ASSERT(list_empty(&entry->log_list));
 565                 ASSERT(RB_EMPTY_NODE(&entry->rb_node));
 566                 if (entry->inode)
 567                         btrfs_add_delayed_iput(BTRFS_I(entry->inode));
 568                 while (!list_empty(&entry->list)) {
 569                         cur = entry->list.next;
 570                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 571                         list_del(&sum->list);
 572                         kvfree(sum);
 573                 }
 574                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 575         }
 576 }
 577
 578 /*
 579  * remove an ordered extent from the tree.  No references are dropped
 580  * and waiters are woken up.
 581  */
 582 void btrfs_remove_ordered_extent(struct btrfs_inode *btrfs_inode,
 583                                  struct btrfs_ordered_extent *entry)
 584 {
 585         struct btrfs_root *root = btrfs_inode->root;
 586         struct btrfs_fs_info *fs_info = root->fs_info;
 587         struct rb_node *node;
 588         bool pending;
 589         bool freespace_inode;
 590
 591         /*
 592          * If this is a free space inode the thread has not acquired the ordered
 593          * extents lockdep map.
 594          */
 595         freespace_inode = btrfs_is_free_space_inode(btrfs_inode);
 596
 597         btrfs_lockdep_acquire(fs_info, btrfs_trans_pending_ordered);
 598         /* This is paired with btrfs_alloc_ordered_extent. */
 599         spin_lock(&btrfs_inode->lock);
 600         btrfs_mod_outstanding_extents(btrfs_inode, -1);
 601         spin_unlock(&btrfs_inode->lock);
 602         if (root != fs_info->tree_root) {
 603                 u64 release;
 604
 605                 if (test_bit(BTRFS_ORDERED_ENCODED, &entry->flags))
 606                         release = entry->disk_num_bytes;
 607                 else
 608                         release = entry->num_bytes;
 609                 btrfs_delalloc_release_metadata(btrfs_inode, release,
 610                                                 test_bit(BTRFS_ORDERED_IOERR,
 611                                                          &entry->flags));
 612         }
 613
 614         percpu_counter_add_batch(&fs_info->ordered_bytes, -entry->num_bytes,
 615                                  fs_info->delalloc_batch);
 616
 617         spin_lock_irq(&btrfs_inode->ordered_tree_lock);
 618         node = &entry->rb_node;
 619         rb_erase(node, &btrfs_inode->ordered_tree);
 620         RB_CLEAR_NODE(node);
 621         if (btrfs_inode->ordered_tree_last == node)
 622                 btrfs_inode->ordered_tree_last = NULL;
 623         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 624         pending = test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags);
 625         spin_unlock_irq(&btrfs_inode->ordered_tree_lock);
 626
 627         /*
 628          * The current running transaction is waiting on us, we need to let it
 629          * know that we're complete and wake it up.
 630          */
 631         if (pending) {
 632                 struct btrfs_transaction *trans;
 633
 634                 /*
 635                  * The checks for trans are just a formality, it should be set,
 636                  * but if it isn't we don't want to deref/assert under the spin
 637                  * lock, so be nice and check if trans is set, but ASSERT() so
 638                  * if it isn't set a developer will notice.
 639                  */
 640                 spin_lock(&fs_info->trans_lock);
 641                 trans = fs_info->running_transaction;
 642                 if (trans)
 643                         refcount_inc(&trans->use_count);
 644                 spin_unlock(&fs_info->trans_lock);
 645
 646                 ASSERT(trans || BTRFS_FS_ERROR(fs_info));
 647                 if (trans) {
 648                         if (atomic_dec_and_test(&trans->pending_ordered))
 649                                 wake_up(&trans->pending_wait);
 650                         btrfs_put_transaction(trans);
 651                 }
 652         }
 653
 654         btrfs_lockdep_release(fs_info, btrfs_trans_pending_ordered);
 655
 656         spin_lock(&root->ordered_extent_lock);
 657         list_del_init(&entry->root_extent_list);
 658         root->nr_ordered_extents--;
 659
 660         trace_btrfs_ordered_extent_remove(btrfs_inode, entry);
 661
 662         if (!root->nr_ordered_extents) {
 663                 spin_lock(&fs_info->ordered_root_lock);
 664                 BUG_ON(list_empty(&root->ordered_root));
 665                 list_del_init(&root->ordered_root);
 666                 spin_unlock(&fs_info->ordered_root_lock);
 667         }
 668         spin_unlock(&root->ordered_extent_lock);
 669         wake_up(&entry->wait);
 670         if (!freespace_inode)
 671                 btrfs_lockdep_release(fs_info, btrfs_ordered_extent);
 672 }
 673
 674 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 675 {
 676         struct btrfs_ordered_extent *ordered;
 677
 678         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 679         btrfs_start_ordered_extent(ordered);
 680         complete(&ordered->completion);
 681 }
 682
 683 /*
 684  * wait for all the ordered extents in a root.  This is done when balancing
 685  * space between drives.
 686  */
 687 u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
 688                                const u64 range_start, const u64 range_len)
 689 {
 690         struct btrfs_fs_info *fs_info = root->fs_info;
 691         LIST_HEAD(splice);
 692         LIST_HEAD(skipped);
 693         LIST_HEAD(works);
 694         struct btrfs_ordered_extent *ordered, *next;
 695         u64 count = 0;
 696         const u64 range_end = range_start + range_len;
 697
 698         mutex_lock(&root->ordered_extent_mutex);
 699         spin_lock(&root->ordered_extent_lock);
 700         list_splice_init(&root->ordered_extents, &splice);
 701         while (!list_empty(&splice) && nr) {
 702                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 703                                            root_extent_list);
 704
 705                 if (range_end <= ordered->disk_bytenr ||
 706                     ordered->disk_bytenr + ordered->disk_num_bytes <= range_start) {
 707                         list_move_tail(&ordered->root_extent_list, &skipped);
 708                         cond_resched_lock(&root->ordered_extent_lock);
 709                         continue;
 710                 }
 711
 712                 list_move_tail(&ordered->root_extent_list,
 713                                &root->ordered_extents);
 714                 refcount_inc(&ordered->refs);
 715                 spin_unlock(&root->ordered_extent_lock);
 716
 717                 btrfs_init_work(&ordered->flush_work,
 718                                 btrfs_run_ordered_extent_work, NULL);
 719                 list_add_tail(&ordered->work_list, &works);
 720                 btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
 721
 722                 cond_resched();
 723                 spin_lock(&root->ordered_extent_lock);
 724                 if (nr != U64_MAX)
 725                         nr--;
 726                 count++;
 727         }
 728         list_splice_tail(&skipped, &root->ordered_extents);
 729         list_splice_tail(&splice, &root->ordered_extents);
 730         spin_unlock(&root->ordered_extent_lock);
 731
 732         list_for_each_entry_safe(ordered, next, &works, work_list) {
 733                 list_del_init(&ordered->work_list);
 734                 wait_for_completion(&ordered->completion);
 735                 btrfs_put_ordered_extent(ordered);
 736                 cond_resched();
 737         }
 738         mutex_unlock(&root->ordered_extent_mutex);
 739
 740         return count;
 741 }
 742
 743 void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
 744                              const u64 range_start, const u64 range_len)
 745 {
 746         struct btrfs_root *root;
 747         LIST_HEAD(splice);
 748         u64 done;
 749
 750         mutex_lock(&fs_info->ordered_operations_mutex);
 751         spin_lock(&fs_info->ordered_root_lock);
 752         list_splice_init(&fs_info->ordered_roots, &splice);
 753         while (!list_empty(&splice) && nr) {
 754                 root = list_first_entry(&splice, struct btrfs_root,
 755                                         ordered_root);
 756                 root = btrfs_grab_root(root);
 757                 BUG_ON(!root);
 758                 list_move_tail(&root->ordered_root,
 759                                &fs_info->ordered_roots);
 760                 spin_unlock(&fs_info->ordered_root_lock);
 761
 762                 done = btrfs_wait_ordered_extents(root, nr,
 763                                                   range_start, range_len);
 764                 btrfs_put_root(root);
 765
 766                 spin_lock(&fs_info->ordered_root_lock);
 767                 if (nr != U64_MAX) {
 768                         nr -= done;
 769                 }
 770         }
 771         list_splice_tail(&splice, &fs_info->ordered_roots);
 772         spin_unlock(&fs_info->ordered_root_lock);
 773         mutex_unlock(&fs_info->ordered_operations_mutex);
 774 }
 775
 776 /*
 777  * Start IO and wait for a given ordered extent to finish.
 778  *
 779  * Wait on page writeback for all the pages in the extent and the IO completion
 780  * code to insert metadata into the btree corresponding to the extent.
 781  */
 782 void btrfs_start_ordered_extent(struct btrfs_ordered_extent *entry)
 783 {
 784         u64 start = entry->file_offset;
 785         u64 end = start + entry->num_bytes - 1;
 786         struct btrfs_inode *inode = BTRFS_I(entry->inode);
 787         bool freespace_inode;
 788
 789         trace_btrfs_ordered_extent_start(inode, entry);
 790
 791         /*
 792          * If this is a free space inode do not take the ordered extents lockdep
 793          * map.
 794          */
 795         freespace_inode = btrfs_is_free_space_inode(inode);
 796
 797         /*
 798          * pages in the range can be dirty, clean or writeback.  We
 799          * start IO on any dirty ones so the wait doesn't stall waiting
 800          * for the flusher thread to find them
 801          */
 802         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 803                 filemap_fdatawrite_range(inode->vfs_inode.i_mapping, start, end);
 804
 805         if (!freespace_inode)
 806                 btrfs_might_wait_for_event(inode->root->fs_info, btrfs_ordered_extent);
 807         wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE, &entry->flags));
 808 }
 809
 810 /*
 811  * Used to wait on ordered extents across a large range of bytes.
 812  */
 813 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 814 {
 815         int ret = 0;
 816         int ret_wb = 0;
 817         u64 end;
 818         u64 orig_end;
 819         struct btrfs_ordered_extent *ordered;
 820
 821         if (start + len < start) {
 822                 orig_end = OFFSET_MAX;
 823         } else {
 824                 orig_end = start + len - 1;
 825                 if (orig_end > OFFSET_MAX)
 826                         orig_end = OFFSET_MAX;
 827         }
 828
 829         /* start IO across the range first to instantiate any delalloc
 830          * extents
 831          */
 832         ret = btrfs_fdatawrite_range(inode, start, orig_end);
 833         if (ret)
 834                 return ret;
 835
 836         /*
 837          * If we have a writeback error don't return immediately. Wait first
 838          * for any ordered extents that haven't completed yet. This is to make
 839          * sure no one can dirty the same page ranges and call writepages()
 840          * before the ordered extents complete - to avoid failures (-EEXIST)
 841          * when adding the new ordered extents to the ordered tree.
 842          */
 843         ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 844
 845         end = orig_end;
 846         while (1) {
 847                 ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode), end);
 848                 if (!ordered)
 849                         break;
 850                 if (ordered->file_offset > orig_end) {
 851                         btrfs_put_ordered_extent(ordered);
 852                         break;
 853                 }
 854                 if (ordered->file_offset + ordered->num_bytes <= start) {
 855                         btrfs_put_ordered_extent(ordered);
 856                         break;
 857                 }
 858                 btrfs_start_ordered_extent(ordered);
 859                 end = ordered->file_offset;
 860                 /*
 861                  * If the ordered extent had an error save the error but don't
 862                  * exit without waiting first for all other ordered extents in
 863                  * the range to complete.
 864                  */
 865                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 866                         ret = -EIO;
 867                 btrfs_put_ordered_extent(ordered);
 868                 if (end == 0 || end == start)
 869                         break;
 870                 end--;
 871         }
 872         return ret_wb ? ret_wb : ret;
 873 }
 874
 875 /*
 876  * find an ordered extent corresponding to file_offset.  return NULL if
 877  * nothing is found, otherwise take a reference on the extent and return it
 878  */
 879 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct btrfs_inode *inode,
 880                                                          u64 file_offset)
 881 {
 882         struct rb_node *node;
 883         struct btrfs_ordered_extent *entry = NULL;
 884         unsigned long flags;
 885
 886         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 887         node = ordered_tree_search(inode, file_offset);
 888         if (!node)
 889                 goto out;
 890
 891         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 892         if (!in_range(file_offset, entry->file_offset, entry->num_bytes))
 893                 entry = NULL;
 894         if (entry) {
 895                 refcount_inc(&entry->refs);
 896                 trace_btrfs_ordered_extent_lookup(inode, entry);
 897         }
 898 out:
 899         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 900         return entry;
 901 }
 902
 903 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 904  * extents that exist in the range, rather than just the start of the range.
 905  */
 906 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
 907                 struct btrfs_inode *inode, u64 file_offset, u64 len)
 908 {
 909         struct rb_node *node;
 910         struct btrfs_ordered_extent *entry = NULL;
 911
 912         spin_lock_irq(&inode->ordered_tree_lock);
 913         node = ordered_tree_search(inode, file_offset);
 914         if (!node) {
 915                 node = ordered_tree_search(inode, file_offset + len);
 916                 if (!node)
 917                         goto out;
 918         }
 919
 920         while (1) {
 921                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 922                 if (range_overlaps(entry, file_offset, len))
 923                         break;
 924
 925                 if (entry->file_offset >= file_offset + len) {
 926                         entry = NULL;
 927                         break;
 928                 }
 929                 entry = NULL;
 930                 node = rb_next(node);
 931                 if (!node)
 932                         break;
 933         }
 934 out:
 935         if (entry) {
 936                 refcount_inc(&entry->refs);
 937                 trace_btrfs_ordered_extent_lookup_range(inode, entry);
 938         }
 939         spin_unlock_irq(&inode->ordered_tree_lock);
 940         return entry;
 941 }
 942
 943 /*
 944  * Adds all ordered extents to the given list. The list ends up sorted by the
 945  * file_offset of the ordered extents.
 946  */
 947 void btrfs_get_ordered_extents_for_logging(struct btrfs_inode *inode,
 948                                            struct list_head *list)
 949 {
 950         struct rb_node *n;
 951
 952         ASSERT(inode_is_locked(&inode->vfs_inode));
 953
 954         spin_lock_irq(&inode->ordered_tree_lock);
 955         for (n = rb_first(&inode->ordered_tree); n; n = rb_next(n)) {
 956                 struct btrfs_ordered_extent *ordered;
 957
 958                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 959
 960                 if (test_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
 961                         continue;
 962
 963                 ASSERT(list_empty(&ordered->log_list));
 964                 list_add_tail(&ordered->log_list, list);
 965                 refcount_inc(&ordered->refs);
 966                 trace_btrfs_ordered_extent_lookup_for_logging(inode, ordered);
 967         }
 968         spin_unlock_irq(&inode->ordered_tree_lock);
 969 }
 970
 971 /*
 972  * lookup and return any extent before 'file_offset'.  NULL is returned
 973  * if none is found
 974  */
 975 struct btrfs_ordered_extent *
 976 btrfs_lookup_first_ordered_extent(struct btrfs_inode *inode, u64 file_offset)
 977 {
 978         struct rb_node *node;
 979         struct btrfs_ordered_extent *entry = NULL;
 980
 981         spin_lock_irq(&inode->ordered_tree_lock);
 982         node = ordered_tree_search(inode, file_offset);
 983         if (!node)
 984                 goto out;
 985
 986         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 987         refcount_inc(&entry->refs);
 988         trace_btrfs_ordered_extent_lookup_first(inode, entry);
 989 out:
 990         spin_unlock_irq(&inode->ordered_tree_lock);
 991         return entry;
 992 }
 993
 994 /*
 995  * Lookup the first ordered extent that overlaps the range
 996  * [@file_offset, @file_offset + @len).
 997  *
 998  * The difference between this and btrfs_lookup_first_ordered_extent() is
 999  * that this one won't return any ordered extent that does not overlap the range.
1000  * And the difference against btrfs_lookup_ordered_extent() is, this function
1001  * ensures the first ordered extent gets returned.
1002  */
1003 struct btrfs_ordered_extent *btrfs_lookup_first_ordered_range(
1004                         struct btrfs_inode *inode, u64 file_offset, u64 len)
1005 {
1006         struct rb_node *node;
1007         struct rb_node *cur;
1008         struct rb_node *prev;
1009         struct rb_node *next;
1010         struct btrfs_ordered_extent *entry = NULL;
1011
1012         spin_lock_irq(&inode->ordered_tree_lock);
1013         node = inode->ordered_tree.rb_node;
1014         /*
1015          * Here we don't want to use tree_search() which will use tree->last
1016          * and screw up the search order.
1017          * And __tree_search() can't return the adjacent ordered extents
1018          * either, thus here we do our own search.
1019          */
1020         while (node) {
1021                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
1022
1023                 if (file_offset < entry->file_offset) {
1024                         node = node->rb_left;
1025                 } else if (file_offset >= entry_end(entry)) {
1026                         node = node->rb_right;
1027                 } else {
1028                         /*
1029                          * Direct hit, got an ordered extent that starts at
1030                          * @file_offset
1031                          */
1032                         goto out;
1033                 }
1034         }
1035         if (!entry) {
1036                 /* Empty tree */
1037                 goto out;
1038         }
1039
1040         cur = &entry->rb_node;
1041         /* We got an entry around @file_offset, check adjacent entries */
1042         if (entry->file_offset < file_offset) {
1043                 prev = cur;
1044                 next = rb_next(cur);
1045         } else {
1046                 prev = rb_prev(cur);
1047                 next = cur;
1048         }
1049         if (prev) {
1050                 entry = rb_entry(prev, struct btrfs_ordered_extent, rb_node);
1051                 if (range_overlaps(entry, file_offset, len))
1052                         goto out;
1053         }
1054         if (next) {
1055                 entry = rb_entry(next, struct btrfs_ordered_extent, rb_node);
1056                 if (range_overlaps(entry, file_offset, len))
1057                         goto out;
1058         }
1059         /* No ordered extent in the range */
1060         entry = NULL;
1061 out:
1062         if (entry) {
1063                 refcount_inc(&entry->refs);
1064                 trace_btrfs_ordered_extent_lookup_first_range(inode, entry);
1065         }
1066
1067         spin_unlock_irq(&inode->ordered_tree_lock);
1068         return entry;
1069 }
1070
1071 /*
1072  * Lock the passed range and ensures all pending ordered extents in it are run
1073  * to completion.
1074  *
1075  * @inode:        Inode whose ordered tree is to be searched
1076  * @start:        Beginning of range to flush
1077  * @end:          Last byte of range to lock
1078  * @cached_state: If passed, will return the extent state responsible for the
1079  *                locked range. It's the caller's responsibility to free the
1080  *                cached state.
1081  *
1082  * Always return with the given range locked, ensuring after it's called no
1083  * order extent can be pending.
1084  */
1085 void btrfs_lock_and_flush_ordered_range(struct btrfs_inode *inode, u64 start,
1086                                         u64 end,
1087                                         struct extent_state **cached_state)
1088 {
1089         struct btrfs_ordered_extent *ordered;
1090         struct extent_state *cache = NULL;
1091         struct extent_state **cachedp = &cache;
1092
1093         if (cached_state)
1094                 cachedp = cached_state;
1095
1096         while (1) {
1097                 lock_extent(&inode->io_tree, start, end, cachedp);
1098                 ordered = btrfs_lookup_ordered_range(inode, start,
1099                                                      end - start + 1);
1100                 if (!ordered) {
1101                         /*
1102                          * If no external cached_state has been passed then
1103                          * decrement the extra ref taken for cachedp since we
1104                          * aren't exposing it outside of this function
1105                          */
1106                         if (!cached_state)
1107                                 refcount_dec(&cache->refs);
1108                         break;
1109                 }
1110                 unlock_extent(&inode->io_tree, start, end, cachedp);
1111                 btrfs_start_ordered_extent(ordered);
1112                 btrfs_put_ordered_extent(ordered);
1113         }
1114 }
1115
1116 /*
1117  * Lock the passed range and ensure all pending ordered extents in it are run
1118  * to completion in nowait mode.
1119  *
1120  * Return true if btrfs_lock_ordered_range does not return any extents,
1121  * otherwise false.
1122  */
1123 bool btrfs_try_lock_ordered_range(struct btrfs_inode *inode, u64 start, u64 end,
1124                                   struct extent_state **cached_state)
1125 {
1126         struct btrfs_ordered_extent *ordered;
1127
1128         if (!try_lock_extent(&inode->io_tree, start, end, cached_state))
1129                 return false;
1130
1131         ordered = btrfs_lookup_ordered_range(inode, start, end - start + 1);
1132         if (!ordered)
1133                 return true;
1134
1135         btrfs_put_ordered_extent(ordered);
1136         unlock_extent(&inode->io_tree, start, end, cached_state);
1137
1138         return false;
1139 }
1140
1141 /* Split out a new ordered extent for this first @len bytes of @ordered. */
1142 struct btrfs_ordered_extent *btrfs_split_ordered_extent(
1143                         struct btrfs_ordered_extent *ordered, u64 len)
1144 {
1145         struct btrfs_inode *inode = BTRFS_I(ordered->inode);
1146         struct btrfs_root *root = inode->root;
1147         struct btrfs_fs_info *fs_info = root->fs_info;
1148         u64 file_offset = ordered->file_offset;
1149         u64 disk_bytenr = ordered->disk_bytenr;
1150         unsigned long flags = ordered->flags;
1151         struct btrfs_ordered_sum *sum, *tmpsum;
1152         struct btrfs_ordered_extent *new;
1153         struct rb_node *node;
1154         u64 offset = 0;
1155
1156         trace_btrfs_ordered_extent_split(inode, ordered);
1157
1158         ASSERT(!(flags & (1U << BTRFS_ORDERED_COMPRESSED)));
1159
1160         /*
1161          * The entire bio must be covered by the ordered extent, but we can't
1162          * reduce the original extent to a zero length either.
1163          */
1164         if (WARN_ON_ONCE(len >= ordered->num_bytes))
1165                 return ERR_PTR(-EINVAL);
1166         /* We cannot split partially completed ordered extents. */
1167         if (ordered->bytes_left) {
1168                 ASSERT(!(flags & ~BTRFS_ORDERED_TYPE_FLAGS));
1169                 if (WARN_ON_ONCE(ordered->bytes_left != ordered->disk_num_bytes))
1170                         return ERR_PTR(-EINVAL);
1171         }
1172         /* We cannot split a compressed ordered extent. */
1173         if (WARN_ON_ONCE(ordered->disk_num_bytes != ordered->num_bytes))
1174                 return ERR_PTR(-EINVAL);
1175
1176         new = alloc_ordered_extent(inode, file_offset, len, len, disk_bytenr,
1177                                    len, 0, flags, ordered->compress_type);
1178         if (IS_ERR(new))
1179                 return new;
1180
1181         /* One ref for the tree. */
1182         refcount_inc(&new->refs);
1183
1184         spin_lock_irq(&root->ordered_extent_lock);
1185         spin_lock(&inode->ordered_tree_lock);
1186         /* Remove from tree once */
1187         node = &ordered->rb_node;
1188         rb_erase(node, &inode->ordered_tree);
1189         RB_CLEAR_NODE(node);
1190         if (inode->ordered_tree_last == node)
1191                 inode->ordered_tree_last = NULL;
1192
1193         ordered->file_offset += len;
1194         ordered->disk_bytenr += len;
1195         ordered->num_bytes -= len;
1196         ordered->disk_num_bytes -= len;
1197         ordered->ram_bytes -= len;
1198
1199         if (test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags)) {
1200                 ASSERT(ordered->bytes_left == 0);
1201                 new->bytes_left = 0;
1202         } else {
1203                 ordered->bytes_left -= len;
1204         }
1205
1206         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags)) {
1207                 if (ordered->truncated_len > len) {
1208                         ordered->truncated_len -= len;
1209                 } else {
1210                         new->truncated_len = ordered->truncated_len;
1211                         ordered->truncated_len = 0;
1212                 }
1213         }
1214
1215         list_for_each_entry_safe(sum, tmpsum, &ordered->list, list) {
1216                 if (offset == len)
1217                         break;
1218                 list_move_tail(&sum->list, &new->list);
1219                 offset += sum->len;
1220         }
1221
1222         /* Re-insert the node */
1223         node = tree_insert(&inode->ordered_tree, ordered->file_offset,
1224                            &ordered->rb_node);
1225         if (node)
1226                 btrfs_panic(fs_info, -EEXIST,
1227                         "zoned: inconsistency in ordered tree at offset %llu",
1228                         ordered->file_offset);
1229
1230         node = tree_insert(&inode->ordered_tree, new->file_offset, &new->rb_node);
1231         if (node)
1232                 btrfs_panic(fs_info, -EEXIST,
1233                         "zoned: inconsistency in ordered tree at offset %llu",
1234                         new->file_offset);
1235         spin_unlock(&inode->ordered_tree_lock);
1236
1237         list_add_tail(&new->root_extent_list, &root->ordered_extents);
1238         root->nr_ordered_extents++;
1239         spin_unlock_irq(&root->ordered_extent_lock);
1240         return new;
1241 }
1242
1243 int __init ordered_data_init(void)
1244 {
1245         btrfs_ordered_extent_cache = KMEM_CACHE(btrfs_ordered_extent, 0);
1246         if (!btrfs_ordered_extent_cache)
1247                 return -ENOMEM;
1248
1249         return 0;
1250 }
1251
1252 void __cold ordered_data_exit(void)
1253 {
1254         kmem_cache_destroy(btrfs_ordered_extent_cache);
1255 }