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 #include "block-group.h"
  23
  24 static struct kmem_cache *btrfs_ordered_extent_cache;
  25
  26 static u64 entry_end(struct btrfs_ordered_extent *entry)
  27 {
  28         if (entry->file_offset + entry->num_bytes < entry->file_offset)
  29                 return (u64)-1;
  30         return entry->file_offset + entry->num_bytes;
  31 }
  32
  33 /* returns NULL if the insertion worked, or it returns the node it did find
  34  * in the tree
  35  */
  36 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  37                                    struct rb_node *node)
  38 {
  39         struct rb_node **p = &root->rb_node;
  40         struct rb_node *parent = NULL;
  41         struct btrfs_ordered_extent *entry;
  42
  43         while (*p) {
  44                 parent = *p;
  45                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  46
  47                 if (file_offset < entry->file_offset)
  48                         p = &(*p)->rb_left;
  49                 else if (file_offset >= entry_end(entry))
  50                         p = &(*p)->rb_right;
  51                 else
  52                         return parent;
  53         }
  54
  55         rb_link_node(node, parent, p);
  56         rb_insert_color(node, root);
  57         return NULL;
  58 }
  59
  60 /*
  61  * look for a given offset in the tree, and if it can't be found return the
  62  * first lesser offset
  63  */
  64 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  65                                      struct rb_node **prev_ret)
  66 {
  67         struct rb_node *n = root->rb_node;
  68         struct rb_node *prev = NULL;
  69         struct rb_node *test;
  70         struct btrfs_ordered_extent *entry;
  71         struct btrfs_ordered_extent *prev_entry = NULL;
  72
  73         while (n) {
  74                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  75                 prev = n;
  76                 prev_entry = entry;
  77
  78                 if (file_offset < entry->file_offset)
  79                         n = n->rb_left;
  80                 else if (file_offset >= entry_end(entry))
  81                         n = n->rb_right;
  82                 else
  83                         return n;
  84         }
  85         if (!prev_ret)
  86                 return NULL;
  87
  88         while (prev && file_offset >= entry_end(prev_entry)) {
  89                 test = rb_next(prev);
  90                 if (!test)
  91                         break;
  92                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
  93                                       rb_node);
  94                 if (file_offset < entry_end(prev_entry))
  95                         break;
  96
  97                 prev = test;
  98         }
  99         if (prev)
 100                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 101                                       rb_node);
 102         while (prev && file_offset < entry_end(prev_entry)) {
 103                 test = rb_prev(prev);
 104                 if (!test)
 105                         break;
 106                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 107                                       rb_node);
 108                 prev = test;
 109         }
 110         *prev_ret = prev;
 111         return NULL;
 112 }
 113
 114 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 115                           u64 len)
 116 {
 117         if (file_offset + len <= entry->file_offset ||
 118             entry->file_offset + entry->num_bytes <= file_offset)
 119                 return 0;
 120         return 1;
 121 }
 122
 123 /*
 124  * look find the first ordered struct that has this offset, otherwise
 125  * the first one less than this offset
 126  */
 127 static inline struct rb_node *ordered_tree_search(struct btrfs_inode *inode,
 128                                                   u64 file_offset)
 129 {
 130         struct rb_node *prev = NULL;
 131         struct rb_node *ret;
 132         struct btrfs_ordered_extent *entry;
 133
 134         if (inode->ordered_tree_last) {
 135                 entry = rb_entry(inode->ordered_tree_last, struct btrfs_ordered_extent,
 136                                  rb_node);
 137                 if (in_range(file_offset, entry->file_offset, entry->num_bytes))
 138                         return inode->ordered_tree_last;
 139         }
 140         ret = __tree_search(&inode->ordered_tree, file_offset, &prev);
 141         if (!ret)
 142                 ret = prev;
 143         if (ret)
 144                 inode->ordered_tree_last = ret;
 145         return ret;
 146 }
 147
 148 static struct btrfs_ordered_extent *alloc_ordered_extent(
 149                         struct btrfs_inode *inode, u64 file_offset, u64 num_bytes,
 150                         u64 ram_bytes, u64 disk_bytenr, u64 disk_num_bytes,
 151                         u64 offset, unsigned long flags, int compress_type)
 152 {
 153         struct btrfs_ordered_extent *entry;
 154         int ret;
 155         u64 qgroup_rsv = 0;
 156
 157         if (flags &
 158             ((1 << BTRFS_ORDERED_NOCOW) | (1 << BTRFS_ORDERED_PREALLOC))) {
 159                 /* For nocow write, we can release the qgroup rsv right now */
 160                 ret = btrfs_qgroup_free_data(inode, NULL, file_offset, num_bytes, &qgroup_rsv);
 161                 if (ret < 0)
 162                         return ERR_PTR(ret);
 163         } else {
 164                 /*
 165                  * The ordered extent has reserved qgroup space, release now
 166                  * and pass the reserved number for qgroup_record to free.
 167                  */
 168                 ret = btrfs_qgroup_release_data(inode, file_offset, num_bytes, &qgroup_rsv);
 169                 if (ret < 0)
 170                         return ERR_PTR(ret);
 171         }
 172         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 173         if (!entry)
 174                 return ERR_PTR(-ENOMEM);
 175
 176         entry->file_offset = file_offset;
 177         entry->num_bytes = num_bytes;
 178         entry->ram_bytes = ram_bytes;
 179         entry->disk_bytenr = disk_bytenr;
 180         entry->disk_num_bytes = disk_num_bytes;
 181         entry->offset = offset;
 182         entry->bytes_left = num_bytes;
 183         entry->inode = BTRFS_I(igrab(&inode->vfs_inode));
 184         entry->compress_type = compress_type;
 185         entry->truncated_len = (u64)-1;
 186         entry->qgroup_rsv = qgroup_rsv;
 187         entry->flags = flags;
 188         refcount_set(&entry->refs, 1);
 189         init_waitqueue_head(&entry->wait);
 190         INIT_LIST_HEAD(&entry->list);
 191         INIT_LIST_HEAD(&entry->log_list);
 192         INIT_LIST_HEAD(&entry->root_extent_list);
 193         INIT_LIST_HEAD(&entry->work_list);
 194         INIT_LIST_HEAD(&entry->bioc_list);
 195         init_completion(&entry->completion);
 196
 197         /*
 198          * We don't need the count_max_extents here, we can assume that all of
 199          * that work has been done at higher layers, so this is truly the
 200          * smallest the extent is going to get.
 201          */
 202         spin_lock(&inode->lock);
 203         btrfs_mod_outstanding_extents(inode, 1);
 204         spin_unlock(&inode->lock);
 205
 206         return entry;
 207 }
 208
 209 static void insert_ordered_extent(struct btrfs_ordered_extent *entry)
 210 {
 211         struct btrfs_inode *inode = entry->inode;
 212         struct btrfs_root *root = inode->root;
 213         struct btrfs_fs_info *fs_info = root->fs_info;
 214         struct rb_node *node;
 215
 216         trace_btrfs_ordered_extent_add(inode, entry);
 217
 218         percpu_counter_add_batch(&fs_info->ordered_bytes, entry->num_bytes,
 219                                  fs_info->delalloc_batch);
 220
 221         /* One ref for the tree. */
 222         refcount_inc(&entry->refs);
 223
 224         spin_lock_irq(&inode->ordered_tree_lock);
 225         node = tree_insert(&inode->ordered_tree, entry->file_offset,
 226                            &entry->rb_node);
 227         if (unlikely(node))
 228                 btrfs_panic(fs_info, -EEXIST,
 229                                 "inconsistency in ordered tree at offset %llu",
 230                                 entry->file_offset);
 231         spin_unlock_irq(&inode->ordered_tree_lock);
 232
 233         spin_lock(&root->ordered_extent_lock);
 234         list_add_tail(&entry->root_extent_list,
 235                       &root->ordered_extents);
 236         root->nr_ordered_extents++;
 237         if (root->nr_ordered_extents == 1) {
 238                 spin_lock(&fs_info->ordered_root_lock);
 239                 BUG_ON(!list_empty(&root->ordered_root));
 240                 list_add_tail(&root->ordered_root, &fs_info->ordered_roots);
 241                 spin_unlock(&fs_info->ordered_root_lock);
 242         }
 243         spin_unlock(&root->ordered_extent_lock);
 244 }
 245
 246 /*
 247  * Add an ordered extent to the per-inode tree.
 248  *
 249  * @inode:           Inode that this extent is for.
 250  * @file_offset:     Logical offset in file where the extent starts.
 251  * @num_bytes:       Logical length of extent in file.
 252  * @ram_bytes:       Full length of unencoded data.
 253  * @disk_bytenr:     Offset of extent on disk.
 254  * @disk_num_bytes:  Size of extent on disk.
 255  * @offset:          Offset into unencoded data where file data starts.
 256  * @flags:           Flags specifying type of extent (1 << BTRFS_ORDERED_*).
 257  * @compress_type:   Compression algorithm used for data.
 258  *
 259  * Most of these parameters correspond to &struct btrfs_file_extent_item. The
 260  * tree is given a single reference on the ordered extent that was inserted, and
 261  * the returned pointer is given a second reference.
 262  *
 263  * Return: the new ordered extent or error pointer.
 264  */
 265 struct btrfs_ordered_extent *btrfs_alloc_ordered_extent(
 266                         struct btrfs_inode *inode, u64 file_offset,
 267                         const struct btrfs_file_extent *file_extent, unsigned long flags)
 268 {
 269         struct btrfs_ordered_extent *entry;
 270
 271         ASSERT((flags & ~BTRFS_ORDERED_TYPE_FLAGS) == 0);
 272
 273         /*
 274          * For regular writes, we just use the members in @file_extent.
 275          *
 276          * For NOCOW, we don't really care about the numbers except @start and
 277          * file_extent->num_bytes, as we won't insert a file extent item at all.
 278          *
 279          * For PREALLOC, we do not use ordered extent members, but
 280          * btrfs_mark_extent_written() handles everything.
 281          *
 282          * So here we always pass 0 as offset for NOCOW/PREALLOC ordered extents,
 283          * or btrfs_split_ordered_extent() cannot handle it correctly.
 284          */
 285         if (flags & ((1U << BTRFS_ORDERED_NOCOW) | (1U << BTRFS_ORDERED_PREALLOC)))
 286                 entry = alloc_ordered_extent(inode, file_offset,
 287                                              file_extent->num_bytes,
 288                                              file_extent->num_bytes,
 289                                              file_extent->disk_bytenr + file_extent->offset,
 290                                              file_extent->num_bytes, 0, flags,
 291                                              file_extent->compression);
 292         else
 293                 entry = alloc_ordered_extent(inode, file_offset,
 294                                              file_extent->num_bytes,
 295                                              file_extent->ram_bytes,
 296                                              file_extent->disk_bytenr,
 297                                              file_extent->disk_num_bytes,
 298                                              file_extent->offset, flags,
 299                                              file_extent->compression);
 300         if (!IS_ERR(entry))
 301                 insert_ordered_extent(entry);
 302         return entry;
 303 }
 304
 305 /*
 306  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 307  * when an ordered extent is finished.  If the list covers more than one
 308  * ordered extent, it is split across multiples.
 309  */
 310 void btrfs_add_ordered_sum(struct btrfs_ordered_extent *entry,
 311                            struct btrfs_ordered_sum *sum)
 312 {
 313         struct btrfs_inode *inode = entry->inode;
 314
 315         spin_lock_irq(&inode->ordered_tree_lock);
 316         list_add_tail(&sum->list, &entry->list);
 317         spin_unlock_irq(&inode->ordered_tree_lock);
 318 }
 319
 320 void btrfs_mark_ordered_extent_error(struct btrfs_ordered_extent *ordered)
 321 {
 322         if (!test_and_set_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 323                 mapping_set_error(ordered->inode->vfs_inode.i_mapping, -EIO);
 324 }
 325
 326 static void finish_ordered_fn(struct btrfs_work *work)
 327 {
 328         struct btrfs_ordered_extent *ordered_extent;
 329
 330         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
 331         btrfs_finish_ordered_io(ordered_extent);
 332 }
 333
 334 static bool can_finish_ordered_extent(struct btrfs_ordered_extent *ordered,
 335                                       struct folio *folio, u64 file_offset,
 336                                       u64 len, bool uptodate)
 337 {
 338         struct btrfs_inode *inode = ordered->inode;
 339         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 340
 341         lockdep_assert_held(&inode->ordered_tree_lock);
 342
 343         if (folio) {
 344                 ASSERT(folio->mapping);
 345                 ASSERT(folio_pos(folio) <= file_offset);
 346                 ASSERT(file_offset + len <= folio_pos(folio) + folio_size(folio));
 347
 348                 /*
 349                  * Ordered (Private2) bit indicates whether we still have
 350                  * pending io unfinished for the ordered extent.
 351                  *
 352                  * If there's no such bit, we need to skip to next range.
 353                  */
 354                 if (!btrfs_folio_test_ordered(fs_info, folio, file_offset, len))
 355                         return false;
 356                 btrfs_folio_clear_ordered(fs_info, folio, file_offset, len);
 357         }
 358
 359         /* Now we're fine to update the accounting. */
 360         if (WARN_ON_ONCE(len > ordered->bytes_left)) {
 361                 btrfs_crit(fs_info,
 362 "bad ordered extent accounting, root=%llu ino=%llu OE offset=%llu OE len=%llu to_dec=%llu left=%llu",
 363                            btrfs_root_id(inode->root), btrfs_ino(inode),
 364                            ordered->file_offset, ordered->num_bytes,
 365                            len, ordered->bytes_left);
 366                 ordered->bytes_left = 0;
 367         } else {
 368                 ordered->bytes_left -= len;
 369         }
 370
 371         if (!uptodate)
 372                 set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
 373
 374         if (ordered->bytes_left)
 375                 return false;
 376
 377         /*
 378          * All the IO of the ordered extent is finished, we need to queue
 379          * the finish_func to be executed.
 380          */
 381         set_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags);
 382         cond_wake_up(&ordered->wait);
 383         refcount_inc(&ordered->refs);
 384         trace_btrfs_ordered_extent_mark_finished(inode, ordered);
 385         return true;
 386 }
 387
 388 static void btrfs_queue_ordered_fn(struct btrfs_ordered_extent *ordered)
 389 {
 390         struct btrfs_inode *inode = ordered->inode;
 391         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 392         struct btrfs_workqueue *wq = btrfs_is_free_space_inode(inode) ?
 393                 fs_info->endio_freespace_worker : fs_info->endio_write_workers;
 394
 395         btrfs_init_work(&ordered->work, finish_ordered_fn, NULL);
 396         btrfs_queue_work(wq, &ordered->work);
 397 }
 398
 399 void btrfs_finish_ordered_extent(struct btrfs_ordered_extent *ordered,
 400                                  struct folio *folio, u64 file_offset, u64 len,
 401                                  bool uptodate)
 402 {
 403         struct btrfs_inode *inode = ordered->inode;
 404         unsigned long flags;
 405         bool ret;
 406
 407         trace_btrfs_finish_ordered_extent(inode, file_offset, len, uptodate);
 408
 409         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 410         ret = can_finish_ordered_extent(ordered, folio, file_offset, len,
 411                                         uptodate);
 412         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 413
 414         /*
 415          * If this is a COW write it means we created new extent maps for the
 416          * range and they point to unwritten locations if we got an error either
 417          * before submitting a bio or during IO.
 418          *
 419          * We have marked the ordered extent with BTRFS_ORDERED_IOERR, and we
 420          * are queuing its completion below. During completion, at
 421          * btrfs_finish_one_ordered(), we will drop the extent maps for the
 422          * unwritten extents.
 423          *
 424          * However because completion runs in a work queue we can end up having
 425          * a fast fsync running before that. In the case of direct IO, once we
 426          * unlock the inode the fsync might start, and we queue the completion
 427          * before unlocking the inode. In the case of buffered IO when writeback
 428          * finishes (end_bbio_data_write()) we queue the completion, so if the
 429          * writeback was triggered by a fast fsync, the fsync might start
 430          * logging before ordered extent completion runs in the work queue.
 431          *
 432          * The fast fsync will log file extent items based on the extent maps it
 433          * finds, so if by the time it collects extent maps the ordered extent
 434          * completion didn't happen yet, it will log file extent items that
 435          * point to unwritten extents, resulting in a corruption if a crash
 436          * happens and the log tree is replayed. Note that a fast fsync does not
 437          * wait for completion of ordered extents in order to reduce latency.
 438          *
 439          * Set a flag in the inode so that the next fast fsync will wait for
 440          * ordered extents to complete before starting to log.
 441          */
 442         if (!uptodate && !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
 443                 set_bit(BTRFS_INODE_COW_WRITE_ERROR, &inode->runtime_flags);
 444
 445         if (ret)
 446                 btrfs_queue_ordered_fn(ordered);
 447 }
 448
 449 /*
 450  * Mark all ordered extents io inside the specified range finished.
 451  *
 452  * @folio:       The involved folio for the operation.
 453  *               For uncompressed buffered IO, the folio status also needs to be
 454  *               updated to indicate whether the pending ordered io is finished.
 455  *               Can be NULL for direct IO and compressed write.
 456  *               For these cases, callers are ensured they won't execute the
 457  *               endio function twice.
 458  *
 459  * This function is called for endio, thus the range must have ordered
 460  * extent(s) covering it.
 461  */
 462 void btrfs_mark_ordered_io_finished(struct btrfs_inode *inode,
 463                                     struct folio *folio, u64 file_offset,
 464                                     u64 num_bytes, bool uptodate)
 465 {
 466         struct rb_node *node;
 467         struct btrfs_ordered_extent *entry = NULL;
 468         unsigned long flags;
 469         u64 cur = file_offset;
 470
 471         trace_btrfs_writepage_end_io_hook(inode, file_offset,
 472                                           file_offset + num_bytes - 1,
 473                                           uptodate);
 474
 475         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 476         while (cur < file_offset + num_bytes) {
 477                 u64 entry_end;
 478                 u64 end;
 479                 u32 len;
 480
 481                 node = ordered_tree_search(inode, cur);
 482                 /* No ordered extents at all */
 483                 if (!node)
 484                         break;
 485
 486                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 487                 entry_end = entry->file_offset + entry->num_bytes;
 488                 /*
 489                  * |<-- OE --->|  |
 490                  *                cur
 491                  * Go to next OE.
 492                  */
 493                 if (cur >= entry_end) {
 494                         node = rb_next(node);
 495                         /* No more ordered extents, exit */
 496                         if (!node)
 497                                 break;
 498                         entry = rb_entry(node, struct btrfs_ordered_extent,
 499                                          rb_node);
 500
 501                         /* Go to next ordered extent and continue */
 502                         cur = entry->file_offset;
 503                         continue;
 504                 }
 505                 /*
 506                  * |    |<--- OE --->|
 507                  * cur
 508                  * Go to the start of OE.
 509                  */
 510                 if (cur < entry->file_offset) {
 511                         cur = entry->file_offset;
 512                         continue;
 513                 }
 514
 515                 /*
 516                  * Now we are definitely inside one ordered extent.
 517                  *
 518                  * |<--- OE --->|
 519                  *      |
 520                  *      cur
 521                  */
 522                 end = min(entry->file_offset + entry->num_bytes,
 523                           file_offset + num_bytes) - 1;
 524                 ASSERT(end + 1 - cur < U32_MAX);
 525                 len = end + 1 - cur;
 526
 527                 if (can_finish_ordered_extent(entry, folio, cur, len, uptodate)) {
 528                         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 529                         btrfs_queue_ordered_fn(entry);
 530                         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 531                 }
 532                 cur += len;
 533         }
 534         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 535 }
 536
 537 /*
 538  * Finish IO for one ordered extent across a given range.  The range can only
 539  * contain one ordered extent.
 540  *
 541  * @cached:      The cached ordered extent. If not NULL, we can skip the tree
 542  *               search and use the ordered extent directly.
 543  *               Will be also used to store the finished ordered extent.
 544  * @file_offset: File offset for the finished IO
 545  * @io_size:     Length of the finish IO range
 546  *
 547  * Return true if the ordered extent is finished in the range, and update
 548  * @cached.
 549  * Return false otherwise.
 550  *
 551  * NOTE: The range can NOT cross multiple ordered extents.
 552  * Thus caller should ensure the range doesn't cross ordered extents.
 553  */
 554 bool btrfs_dec_test_ordered_pending(struct btrfs_inode *inode,
 555                                     struct btrfs_ordered_extent **cached,
 556                                     u64 file_offset, u64 io_size)
 557 {
 558         struct rb_node *node;
 559         struct btrfs_ordered_extent *entry = NULL;
 560         unsigned long flags;
 561         bool finished = false;
 562
 563         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 564         if (cached && *cached) {
 565                 entry = *cached;
 566                 goto have_entry;
 567         }
 568
 569         node = ordered_tree_search(inode, file_offset);
 570         if (!node)
 571                 goto out;
 572
 573         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 574 have_entry:
 575         if (!in_range(file_offset, entry->file_offset, entry->num_bytes))
 576                 goto out;
 577
 578         if (io_size > entry->bytes_left)
 579                 btrfs_crit(inode->root->fs_info,
 580                            "bad ordered accounting left %llu size %llu",
 581                        entry->bytes_left, io_size);
 582
 583         entry->bytes_left -= io_size;
 584
 585         if (entry->bytes_left == 0) {
 586                 /*
 587                  * Ensure only one caller can set the flag and finished_ret
 588                  * accordingly
 589                  */
 590                 finished = !test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 591                 /* test_and_set_bit implies a barrier */
 592                 cond_wake_up_nomb(&entry->wait);
 593         }
 594 out:
 595         if (finished && cached && entry) {
 596                 *cached = entry;
 597                 refcount_inc(&entry->refs);
 598                 trace_btrfs_ordered_extent_dec_test_pending(inode, entry);
 599         }
 600         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 601         return finished;
 602 }
 603
 604 /*
 605  * used to drop a reference on an ordered extent.  This will free
 606  * the extent if the last reference is dropped
 607  */
 608 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 609 {
 610         struct list_head *cur;
 611         struct btrfs_ordered_sum *sum;
 612
 613         trace_btrfs_ordered_extent_put(entry->inode, entry);
 614
 615         if (refcount_dec_and_test(&entry->refs)) {
 616                 ASSERT(list_empty(&entry->root_extent_list));
 617                 ASSERT(list_empty(&entry->log_list));
 618                 ASSERT(RB_EMPTY_NODE(&entry->rb_node));
 619                 if (entry->inode)
 620                         btrfs_add_delayed_iput(entry->inode);
 621                 while (!list_empty(&entry->list)) {
 622                         cur = entry->list.next;
 623                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 624                         list_del(&sum->list);
 625                         kvfree(sum);
 626                 }
 627                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 628         }
 629 }
 630
 631 /*
 632  * remove an ordered extent from the tree.  No references are dropped
 633  * and waiters are woken up.
 634  */
 635 void btrfs_remove_ordered_extent(struct btrfs_inode *btrfs_inode,
 636                                  struct btrfs_ordered_extent *entry)
 637 {
 638         struct btrfs_root *root = btrfs_inode->root;
 639         struct btrfs_fs_info *fs_info = root->fs_info;
 640         struct rb_node *node;
 641         bool pending;
 642         bool freespace_inode;
 643
 644         /*
 645          * If this is a free space inode the thread has not acquired the ordered
 646          * extents lockdep map.
 647          */
 648         freespace_inode = btrfs_is_free_space_inode(btrfs_inode);
 649
 650         btrfs_lockdep_acquire(fs_info, btrfs_trans_pending_ordered);
 651         /* This is paired with alloc_ordered_extent(). */
 652         spin_lock(&btrfs_inode->lock);
 653         btrfs_mod_outstanding_extents(btrfs_inode, -1);
 654         spin_unlock(&btrfs_inode->lock);
 655         if (root != fs_info->tree_root) {
 656                 u64 release;
 657
 658                 if (test_bit(BTRFS_ORDERED_ENCODED, &entry->flags))
 659                         release = entry->disk_num_bytes;
 660                 else
 661                         release = entry->num_bytes;
 662                 btrfs_delalloc_release_metadata(btrfs_inode, release,
 663                                                 test_bit(BTRFS_ORDERED_IOERR,
 664                                                          &entry->flags));
 665         }
 666
 667         percpu_counter_add_batch(&fs_info->ordered_bytes, -entry->num_bytes,
 668                                  fs_info->delalloc_batch);
 669
 670         spin_lock_irq(&btrfs_inode->ordered_tree_lock);
 671         node = &entry->rb_node;
 672         rb_erase(node, &btrfs_inode->ordered_tree);
 673         RB_CLEAR_NODE(node);
 674         if (btrfs_inode->ordered_tree_last == node)
 675                 btrfs_inode->ordered_tree_last = NULL;
 676         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 677         pending = test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags);
 678         spin_unlock_irq(&btrfs_inode->ordered_tree_lock);
 679
 680         /*
 681          * The current running transaction is waiting on us, we need to let it
 682          * know that we're complete and wake it up.
 683          */
 684         if (pending) {
 685                 struct btrfs_transaction *trans;
 686
 687                 /*
 688                  * The checks for trans are just a formality, it should be set,
 689                  * but if it isn't we don't want to deref/assert under the spin
 690                  * lock, so be nice and check if trans is set, but ASSERT() so
 691                  * if it isn't set a developer will notice.
 692                  */
 693                 spin_lock(&fs_info->trans_lock);
 694                 trans = fs_info->running_transaction;
 695                 if (trans)
 696                         refcount_inc(&trans->use_count);
 697                 spin_unlock(&fs_info->trans_lock);
 698
 699                 ASSERT(trans || BTRFS_FS_ERROR(fs_info));
 700                 if (trans) {
 701                         if (atomic_dec_and_test(&trans->pending_ordered))
 702                                 wake_up(&trans->pending_wait);
 703                         btrfs_put_transaction(trans);
 704                 }
 705         }
 706
 707         btrfs_lockdep_release(fs_info, btrfs_trans_pending_ordered);
 708
 709         spin_lock(&root->ordered_extent_lock);
 710         list_del_init(&entry->root_extent_list);
 711         root->nr_ordered_extents--;
 712
 713         trace_btrfs_ordered_extent_remove(btrfs_inode, entry);
 714
 715         if (!root->nr_ordered_extents) {
 716                 spin_lock(&fs_info->ordered_root_lock);
 717                 BUG_ON(list_empty(&root->ordered_root));
 718                 list_del_init(&root->ordered_root);
 719                 spin_unlock(&fs_info->ordered_root_lock);
 720         }
 721         spin_unlock(&root->ordered_extent_lock);
 722         wake_up(&entry->wait);
 723         if (!freespace_inode)
 724                 btrfs_lockdep_release(fs_info, btrfs_ordered_extent);
 725 }
 726
 727 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 728 {
 729         struct btrfs_ordered_extent *ordered;
 730
 731         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 732         btrfs_start_ordered_extent(ordered);
 733         complete(&ordered->completion);
 734 }
 735
 736 /*
 737  * Wait for all the ordered extents in a root. Use @bg as range or do whole
 738  * range if it's NULL.
 739  */
 740 u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
 741                                const struct btrfs_block_group *bg)
 742 {
 743         struct btrfs_fs_info *fs_info = root->fs_info;
 744         LIST_HEAD(splice);
 745         LIST_HEAD(skipped);
 746         LIST_HEAD(works);
 747         struct btrfs_ordered_extent *ordered, *next;
 748         u64 count = 0;
 749         u64 range_start, range_len;
 750         u64 range_end;
 751
 752         if (bg) {
 753                 range_start = bg->start;
 754                 range_len = bg->length;
 755         } else {
 756                 range_start = 0;
 757                 range_len = U64_MAX;
 758         }
 759         range_end = range_start + range_len;
 760
 761         mutex_lock(&root->ordered_extent_mutex);
 762         spin_lock(&root->ordered_extent_lock);
 763         list_splice_init(&root->ordered_extents, &splice);
 764         while (!list_empty(&splice) && nr) {
 765                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 766                                            root_extent_list);
 767
 768                 if (range_end <= ordered->disk_bytenr ||
 769                     ordered->disk_bytenr + ordered->disk_num_bytes <= range_start) {
 770                         list_move_tail(&ordered->root_extent_list, &skipped);
 771                         cond_resched_lock(&root->ordered_extent_lock);
 772                         continue;
 773                 }
 774
 775                 list_move_tail(&ordered->root_extent_list,
 776                                &root->ordered_extents);
 777                 refcount_inc(&ordered->refs);
 778                 spin_unlock(&root->ordered_extent_lock);
 779
 780                 btrfs_init_work(&ordered->flush_work,
 781                                 btrfs_run_ordered_extent_work, NULL);
 782                 list_add_tail(&ordered->work_list, &works);
 783                 btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
 784
 785                 cond_resched();
 786                 if (nr != U64_MAX)
 787                         nr--;
 788                 count++;
 789                 spin_lock(&root->ordered_extent_lock);
 790         }
 791         list_splice_tail(&skipped, &root->ordered_extents);
 792         list_splice_tail(&splice, &root->ordered_extents);
 793         spin_unlock(&root->ordered_extent_lock);
 794
 795         list_for_each_entry_safe(ordered, next, &works, work_list) {
 796                 list_del_init(&ordered->work_list);
 797                 wait_for_completion(&ordered->completion);
 798                 btrfs_put_ordered_extent(ordered);
 799                 cond_resched();
 800         }
 801         mutex_unlock(&root->ordered_extent_mutex);
 802
 803         return count;
 804 }
 805
 806 /*
 807  * Wait for @nr ordered extents that intersect the @bg, or the whole range of
 808  * the filesystem if @bg is NULL.
 809  */
 810 void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
 811                               const struct btrfs_block_group *bg)
 812 {
 813         struct btrfs_root *root;
 814         LIST_HEAD(splice);
 815         u64 done;
 816
 817         mutex_lock(&fs_info->ordered_operations_mutex);
 818         spin_lock(&fs_info->ordered_root_lock);
 819         list_splice_init(&fs_info->ordered_roots, &splice);
 820         while (!list_empty(&splice) && nr) {
 821                 root = list_first_entry(&splice, struct btrfs_root,
 822                                         ordered_root);
 823                 root = btrfs_grab_root(root);
 824                 BUG_ON(!root);
 825                 list_move_tail(&root->ordered_root,
 826                                &fs_info->ordered_roots);
 827                 spin_unlock(&fs_info->ordered_root_lock);
 828
 829                 done = btrfs_wait_ordered_extents(root, nr, bg);
 830                 btrfs_put_root(root);
 831
 832                 if (nr != U64_MAX)
 833                         nr -= done;
 834
 835                 spin_lock(&fs_info->ordered_root_lock);
 836         }
 837         list_splice_tail(&splice, &fs_info->ordered_roots);
 838         spin_unlock(&fs_info->ordered_root_lock);
 839         mutex_unlock(&fs_info->ordered_operations_mutex);
 840 }
 841
 842 /*
 843  * Start IO and wait for a given ordered extent to finish.
 844  *
 845  * Wait on page writeback for all the pages in the extent and the IO completion
 846  * code to insert metadata into the btree corresponding to the extent.
 847  */
 848 void btrfs_start_ordered_extent(struct btrfs_ordered_extent *entry)
 849 {
 850         u64 start = entry->file_offset;
 851         u64 end = start + entry->num_bytes - 1;
 852         struct btrfs_inode *inode = entry->inode;
 853         bool freespace_inode;
 854
 855         trace_btrfs_ordered_extent_start(inode, entry);
 856
 857         /*
 858          * If this is a free space inode do not take the ordered extents lockdep
 859          * map.
 860          */
 861         freespace_inode = btrfs_is_free_space_inode(inode);
 862
 863         /*
 864          * pages in the range can be dirty, clean or writeback.  We
 865          * start IO on any dirty ones so the wait doesn't stall waiting
 866          * for the flusher thread to find them
 867          */
 868         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 869                 filemap_fdatawrite_range(inode->vfs_inode.i_mapping, start, end);
 870
 871         if (!freespace_inode)
 872                 btrfs_might_wait_for_event(inode->root->fs_info, btrfs_ordered_extent);
 873         wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE, &entry->flags));
 874 }
 875
 876 /*
 877  * Used to wait on ordered extents across a large range of bytes.
 878  */
 879 int btrfs_wait_ordered_range(struct btrfs_inode *inode, u64 start, u64 len)
 880 {
 881         int ret = 0;
 882         int ret_wb = 0;
 883         u64 end;
 884         u64 orig_end;
 885         struct btrfs_ordered_extent *ordered;
 886
 887         if (start + len < start) {
 888                 orig_end = OFFSET_MAX;
 889         } else {
 890                 orig_end = start + len - 1;
 891                 if (orig_end > OFFSET_MAX)
 892                         orig_end = OFFSET_MAX;
 893         }
 894
 895         /* start IO across the range first to instantiate any delalloc
 896          * extents
 897          */
 898         ret = btrfs_fdatawrite_range(inode, start, orig_end);
 899         if (ret)
 900                 return ret;
 901
 902         /*
 903          * If we have a writeback error don't return immediately. Wait first
 904          * for any ordered extents that haven't completed yet. This is to make
 905          * sure no one can dirty the same page ranges and call writepages()
 906          * before the ordered extents complete - to avoid failures (-EEXIST)
 907          * when adding the new ordered extents to the ordered tree.
 908          */
 909         ret_wb = filemap_fdatawait_range(inode->vfs_inode.i_mapping, start, orig_end);
 910
 911         end = orig_end;
 912         while (1) {
 913                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
 914                 if (!ordered)
 915                         break;
 916                 if (ordered->file_offset > orig_end) {
 917                         btrfs_put_ordered_extent(ordered);
 918                         break;
 919                 }
 920                 if (ordered->file_offset + ordered->num_bytes <= start) {
 921                         btrfs_put_ordered_extent(ordered);
 922                         break;
 923                 }
 924                 btrfs_start_ordered_extent(ordered);
 925                 end = ordered->file_offset;
 926                 /*
 927                  * If the ordered extent had an error save the error but don't
 928                  * exit without waiting first for all other ordered extents in
 929                  * the range to complete.
 930                  */
 931                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 932                         ret = -EIO;
 933                 btrfs_put_ordered_extent(ordered);
 934                 if (end == 0 || end == start)
 935                         break;
 936                 end--;
 937         }
 938         return ret_wb ? ret_wb : ret;
 939 }
 940
 941 /*
 942  * find an ordered extent corresponding to file_offset.  return NULL if
 943  * nothing is found, otherwise take a reference on the extent and return it
 944  */
 945 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct btrfs_inode *inode,
 946                                                          u64 file_offset)
 947 {
 948         struct rb_node *node;
 949         struct btrfs_ordered_extent *entry = NULL;
 950         unsigned long flags;
 951
 952         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 953         node = ordered_tree_search(inode, file_offset);
 954         if (!node)
 955                 goto out;
 956
 957         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 958         if (!in_range(file_offset, entry->file_offset, entry->num_bytes))
 959                 entry = NULL;
 960         if (entry) {
 961                 refcount_inc(&entry->refs);
 962                 trace_btrfs_ordered_extent_lookup(inode, entry);
 963         }
 964 out:
 965         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 966         return entry;
 967 }
 968
 969 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 970  * extents that exist in the range, rather than just the start of the range.
 971  */
 972 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
 973                 struct btrfs_inode *inode, u64 file_offset, u64 len)
 974 {
 975         struct rb_node *node;
 976         struct btrfs_ordered_extent *entry = NULL;
 977
 978         spin_lock_irq(&inode->ordered_tree_lock);
 979         node = ordered_tree_search(inode, file_offset);
 980         if (!node) {
 981                 node = ordered_tree_search(inode, file_offset + len);
 982                 if (!node)
 983                         goto out;
 984         }
 985
 986         while (1) {
 987                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 988                 if (range_overlaps(entry, file_offset, len))
 989                         break;
 990
 991                 if (entry->file_offset >= file_offset + len) {
 992                         entry = NULL;
 993                         break;
 994                 }
 995                 entry = NULL;
 996                 node = rb_next(node);
 997                 if (!node)
 998                         break;
 999         }
1000 out:
1001         if (entry) {
1002                 refcount_inc(&entry->refs);
1003                 trace_btrfs_ordered_extent_lookup_range(inode, entry);
1004         }
1005         spin_unlock_irq(&inode->ordered_tree_lock);
1006         return entry;
1007 }
1008
1009 /*
1010  * Adds all ordered extents to the given list. The list ends up sorted by the
1011  * file_offset of the ordered extents.
1012  */
1013 void btrfs_get_ordered_extents_for_logging(struct btrfs_inode *inode,
1014                                            struct list_head *list)
1015 {
1016         struct rb_node *n;
1017
1018         btrfs_assert_inode_locked(inode);
1019
1020         spin_lock_irq(&inode->ordered_tree_lock);
1021         for (n = rb_first(&inode->ordered_tree); n; n = rb_next(n)) {
1022                 struct btrfs_ordered_extent *ordered;
1023
1024                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
1025
1026                 if (test_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
1027                         continue;
1028
1029                 ASSERT(list_empty(&ordered->log_list));
1030                 list_add_tail(&ordered->log_list, list);
1031                 refcount_inc(&ordered->refs);
1032                 trace_btrfs_ordered_extent_lookup_for_logging(inode, ordered);
1033         }
1034         spin_unlock_irq(&inode->ordered_tree_lock);
1035 }
1036
1037 /*
1038  * lookup and return any extent before 'file_offset'.  NULL is returned
1039  * if none is found
1040  */
1041 struct btrfs_ordered_extent *
1042 btrfs_lookup_first_ordered_extent(struct btrfs_inode *inode, u64 file_offset)
1043 {
1044         struct rb_node *node;
1045         struct btrfs_ordered_extent *entry = NULL;
1046
1047         spin_lock_irq(&inode->ordered_tree_lock);
1048         node = ordered_tree_search(inode, file_offset);
1049         if (!node)
1050                 goto out;
1051
1052         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
1053         refcount_inc(&entry->refs);
1054         trace_btrfs_ordered_extent_lookup_first(inode, entry);
1055 out:
1056         spin_unlock_irq(&inode->ordered_tree_lock);
1057         return entry;
1058 }
1059
1060 /*
1061  * Lookup the first ordered extent that overlaps the range
1062  * [@file_offset, @file_offset + @len).
1063  *
1064  * The difference between this and btrfs_lookup_first_ordered_extent() is
1065  * that this one won't return any ordered extent that does not overlap the range.
1066  * And the difference against btrfs_lookup_ordered_extent() is, this function
1067  * ensures the first ordered extent gets returned.
1068  */
1069 struct btrfs_ordered_extent *btrfs_lookup_first_ordered_range(
1070                         struct btrfs_inode *inode, u64 file_offset, u64 len)
1071 {
1072         struct rb_node *node;
1073         struct rb_node *cur;
1074         struct rb_node *prev;
1075         struct rb_node *next;
1076         struct btrfs_ordered_extent *entry = NULL;
1077
1078         spin_lock_irq(&inode->ordered_tree_lock);
1079         node = inode->ordered_tree.rb_node;
1080         /*
1081          * Here we don't want to use tree_search() which will use tree->last
1082          * and screw up the search order.
1083          * And __tree_search() can't return the adjacent ordered extents
1084          * either, thus here we do our own search.
1085          */
1086         while (node) {
1087                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
1088
1089                 if (file_offset < entry->file_offset) {
1090                         node = node->rb_left;
1091                 } else if (file_offset >= entry_end(entry)) {
1092                         node = node->rb_right;
1093                 } else {
1094                         /*
1095                          * Direct hit, got an ordered extent that starts at
1096                          * @file_offset
1097                          */
1098                         goto out;
1099                 }
1100         }
1101         if (!entry) {
1102                 /* Empty tree */
1103                 goto out;
1104         }
1105
1106         cur = &entry->rb_node;
1107         /* We got an entry around @file_offset, check adjacent entries */
1108         if (entry->file_offset < file_offset) {
1109                 prev = cur;
1110                 next = rb_next(cur);
1111         } else {
1112                 prev = rb_prev(cur);
1113                 next = cur;
1114         }
1115         if (prev) {
1116                 entry = rb_entry(prev, struct btrfs_ordered_extent, rb_node);
1117                 if (range_overlaps(entry, file_offset, len))
1118                         goto out;
1119         }
1120         if (next) {
1121                 entry = rb_entry(next, struct btrfs_ordered_extent, rb_node);
1122                 if (range_overlaps(entry, file_offset, len))
1123                         goto out;
1124         }
1125         /* No ordered extent in the range */
1126         entry = NULL;
1127 out:
1128         if (entry) {
1129                 refcount_inc(&entry->refs);
1130                 trace_btrfs_ordered_extent_lookup_first_range(inode, entry);
1131         }
1132
1133         spin_unlock_irq(&inode->ordered_tree_lock);
1134         return entry;
1135 }
1136
1137 /*
1138  * Lock the passed range and ensures all pending ordered extents in it are run
1139  * to completion.
1140  *
1141  * @inode:        Inode whose ordered tree is to be searched
1142  * @start:        Beginning of range to flush
1143  * @end:          Last byte of range to lock
1144  * @cached_state: If passed, will return the extent state responsible for the
1145  *                locked range. It's the caller's responsibility to free the
1146  *                cached state.
1147  *
1148  * Always return with the given range locked, ensuring after it's called no
1149  * order extent can be pending.
1150  */
1151 void btrfs_lock_and_flush_ordered_range(struct btrfs_inode *inode, u64 start,
1152                                         u64 end,
1153                                         struct extent_state **cached_state)
1154 {
1155         struct btrfs_ordered_extent *ordered;
1156         struct extent_state *cache = NULL;
1157         struct extent_state **cachedp = &cache;
1158
1159         if (cached_state)
1160                 cachedp = cached_state;
1161
1162         while (1) {
1163                 lock_extent(&inode->io_tree, start, end, cachedp);
1164                 ordered = btrfs_lookup_ordered_range(inode, start,
1165                                                      end - start + 1);
1166                 if (!ordered) {
1167                         /*
1168                          * If no external cached_state has been passed then
1169                          * decrement the extra ref taken for cachedp since we
1170                          * aren't exposing it outside of this function
1171                          */
1172                         if (!cached_state)
1173                                 refcount_dec(&cache->refs);
1174                         break;
1175                 }
1176                 unlock_extent(&inode->io_tree, start, end, cachedp);
1177                 btrfs_start_ordered_extent(ordered);
1178                 btrfs_put_ordered_extent(ordered);
1179         }
1180 }
1181
1182 /*
1183  * Lock the passed range and ensure all pending ordered extents in it are run
1184  * to completion in nowait mode.
1185  *
1186  * Return true if btrfs_lock_ordered_range does not return any extents,
1187  * otherwise false.
1188  */
1189 bool btrfs_try_lock_ordered_range(struct btrfs_inode *inode, u64 start, u64 end,
1190                                   struct extent_state **cached_state)
1191 {
1192         struct btrfs_ordered_extent *ordered;
1193
1194         if (!try_lock_extent(&inode->io_tree, start, end, cached_state))
1195                 return false;
1196
1197         ordered = btrfs_lookup_ordered_range(inode, start, end - start + 1);
1198         if (!ordered)
1199                 return true;
1200
1201         btrfs_put_ordered_extent(ordered);
1202         unlock_extent(&inode->io_tree, start, end, cached_state);
1203
1204         return false;
1205 }
1206
1207 /* Split out a new ordered extent for this first @len bytes of @ordered. */
1208 struct btrfs_ordered_extent *btrfs_split_ordered_extent(
1209                         struct btrfs_ordered_extent *ordered, u64 len)
1210 {
1211         struct btrfs_inode *inode = ordered->inode;
1212         struct btrfs_root *root = inode->root;
1213         struct btrfs_fs_info *fs_info = root->fs_info;
1214         u64 file_offset = ordered->file_offset;
1215         u64 disk_bytenr = ordered->disk_bytenr;
1216         unsigned long flags = ordered->flags;
1217         struct btrfs_ordered_sum *sum, *tmpsum;
1218         struct btrfs_ordered_extent *new;
1219         struct rb_node *node;
1220         u64 offset = 0;
1221
1222         trace_btrfs_ordered_extent_split(inode, ordered);
1223
1224         ASSERT(!(flags & (1U << BTRFS_ORDERED_COMPRESSED)));
1225
1226         /*
1227          * The entire bio must be covered by the ordered extent, but we can't
1228          * reduce the original extent to a zero length either.
1229          */
1230         if (WARN_ON_ONCE(len >= ordered->num_bytes))
1231                 return ERR_PTR(-EINVAL);
1232         /* We cannot split partially completed ordered extents. */
1233         if (ordered->bytes_left) {
1234                 ASSERT(!(flags & ~BTRFS_ORDERED_TYPE_FLAGS));
1235                 if (WARN_ON_ONCE(ordered->bytes_left != ordered->disk_num_bytes))
1236                         return ERR_PTR(-EINVAL);
1237         }
1238         /* We cannot split a compressed ordered extent. */
1239         if (WARN_ON_ONCE(ordered->disk_num_bytes != ordered->num_bytes))
1240                 return ERR_PTR(-EINVAL);
1241
1242         new = alloc_ordered_extent(inode, file_offset, len, len, disk_bytenr,
1243                                    len, 0, flags, ordered->compress_type);
1244         if (IS_ERR(new))
1245                 return new;
1246
1247         /* One ref for the tree. */
1248         refcount_inc(&new->refs);
1249
1250         /*
1251          * Take the root's ordered_extent_lock to avoid a race with
1252          * btrfs_wait_ordered_extents() when updating the disk_bytenr and
1253          * disk_num_bytes fields of the ordered extent below. And we disable
1254          * IRQs because the inode's ordered_tree_lock is used in IRQ context
1255          * elsewhere.
1256          *
1257          * There's no concern about a previous caller of
1258          * btrfs_wait_ordered_extents() getting the trimmed ordered extent
1259          * before we insert the new one, because even if it gets the ordered
1260          * extent before it's trimmed and the new one inserted, right before it
1261          * uses it or during its use, the ordered extent might have been
1262          * trimmed in the meanwhile, and it missed the new ordered extent.
1263          * There's no way around this and it's harmless for current use cases,
1264          * so we take the root's ordered_extent_lock to fix that race during
1265          * trimming and silence tools like KCSAN.
1266          */
1267         spin_lock_irq(&root->ordered_extent_lock);
1268         spin_lock(&inode->ordered_tree_lock);
1269
1270         /*
1271          * We don't have overlapping ordered extents (that would imply double
1272          * allocation of extents) and we checked above that the split length
1273          * does not cross the ordered extent's num_bytes field, so there's
1274          * no need to remove it and re-insert it in the tree.
1275          */
1276         ordered->file_offset += len;
1277         ordered->disk_bytenr += len;
1278         ordered->num_bytes -= len;
1279         ordered->disk_num_bytes -= len;
1280         ordered->ram_bytes -= len;
1281
1282         if (test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags)) {
1283                 ASSERT(ordered->bytes_left == 0);
1284                 new->bytes_left = 0;
1285         } else {
1286                 ordered->bytes_left -= len;
1287         }
1288
1289         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags)) {
1290                 if (ordered->truncated_len > len) {
1291                         ordered->truncated_len -= len;
1292                 } else {
1293                         new->truncated_len = ordered->truncated_len;
1294                         ordered->truncated_len = 0;
1295                 }
1296         }
1297
1298         list_for_each_entry_safe(sum, tmpsum, &ordered->list, list) {
1299                 if (offset == len)
1300                         break;
1301                 list_move_tail(&sum->list, &new->list);
1302                 offset += sum->len;
1303         }
1304
1305         node = tree_insert(&inode->ordered_tree, new->file_offset, &new->rb_node);
1306         if (unlikely(node))
1307                 btrfs_panic(fs_info, -EEXIST,
1308                         "inconsistency in ordered tree at offset %llu after split",
1309                         new->file_offset);
1310         spin_unlock(&inode->ordered_tree_lock);
1311
1312         list_add_tail(&new->root_extent_list, &root->ordered_extents);
1313         root->nr_ordered_extents++;
1314         spin_unlock_irq(&root->ordered_extent_lock);
1315         return new;
1316 }
1317
1318 int __init ordered_data_init(void)
1319 {
1320         btrfs_ordered_extent_cache = KMEM_CACHE(btrfs_ordered_extent, 0);
1321         if (!btrfs_ordered_extent_cache)
1322                 return -ENOMEM;
1323
1324         return 0;
1325 }
1326
1327 void __cold ordered_data_exit(void)
1328 {
1329         kmem_cache_destroy(btrfs_ordered_extent_cache);
1330 }