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 "misc.h"
  11 #include "ctree.h"
  12 #include "transaction.h"
  13 #include "btrfs_inode.h"
  14 #include "extent_io.h"
  15 #include "disk-io.h"
  16 #include "compression.h"
  17 #include "delalloc-space.h"
  18 #include "qgroup.h"
  19
  20 static struct kmem_cache *btrfs_ordered_extent_cache;
  21
  22 static u64 entry_end(struct btrfs_ordered_extent *entry)
  23 {
  24         if (entry->file_offset + entry->num_bytes < entry->file_offset)
  25                 return (u64)-1;
  26         return entry->file_offset + entry->num_bytes;
  27 }
  28
  29 /* returns NULL if the insertion worked, or it returns the node it did find
  30  * in the tree
  31  */
  32 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  33                                    struct rb_node *node)
  34 {
  35         struct rb_node **p = &root->rb_node;
  36         struct rb_node *parent = NULL;
  37         struct btrfs_ordered_extent *entry;
  38
  39         while (*p) {
  40                 parent = *p;
  41                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  42
  43                 if (file_offset < entry->file_offset)
  44                         p = &(*p)->rb_left;
  45                 else if (file_offset >= entry_end(entry))
  46                         p = &(*p)->rb_right;
  47                 else
  48                         return parent;
  49         }
  50
  51         rb_link_node(node, parent, p);
  52         rb_insert_color(node, root);
  53         return NULL;
  54 }
  55
  56 /*
  57  * look for a given offset in the tree, and if it can't be found return the
  58  * first lesser offset
  59  */
  60 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  61                                      struct rb_node **prev_ret)
  62 {
  63         struct rb_node *n = root->rb_node;
  64         struct rb_node *prev = NULL;
  65         struct rb_node *test;
  66         struct btrfs_ordered_extent *entry;
  67         struct btrfs_ordered_extent *prev_entry = NULL;
  68
  69         while (n) {
  70                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  71                 prev = n;
  72                 prev_entry = entry;
  73
  74                 if (file_offset < entry->file_offset)
  75                         n = n->rb_left;
  76                 else if (file_offset >= entry_end(entry))
  77                         n = n->rb_right;
  78                 else
  79                         return n;
  80         }
  81         if (!prev_ret)
  82                 return NULL;
  83
  84         while (prev && file_offset >= entry_end(prev_entry)) {
  85                 test = rb_next(prev);
  86                 if (!test)
  87                         break;
  88                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
  89                                       rb_node);
  90                 if (file_offset < entry_end(prev_entry))
  91                         break;
  92
  93                 prev = test;
  94         }
  95         if (prev)
  96                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
  97                                       rb_node);
  98         while (prev && file_offset < entry_end(prev_entry)) {
  99                 test = rb_prev(prev);
 100                 if (!test)
 101                         break;
 102                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 103                                       rb_node);
 104                 prev = test;
 105         }
 106         *prev_ret = prev;
 107         return NULL;
 108 }
 109
 110 /*
 111  * helper to check if a given offset is inside a given entry
 112  */
 113 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 114 {
 115         if (file_offset < entry->file_offset ||
 116             entry->file_offset + entry->num_bytes <= file_offset)
 117                 return 0;
 118         return 1;
 119 }
 120
 121 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 122                           u64 len)
 123 {
 124         if (file_offset + len <= entry->file_offset ||
 125             entry->file_offset + entry->num_bytes <= file_offset)
 126                 return 0;
 127         return 1;
 128 }
 129
 130 /*
 131  * look find the first ordered struct that has this offset, otherwise
 132  * the first one less than this offset
 133  */
 134 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 135                                           u64 file_offset)
 136 {
 137         struct rb_root *root = &tree->tree;
 138         struct rb_node *prev = NULL;
 139         struct rb_node *ret;
 140         struct btrfs_ordered_extent *entry;
 141
 142         if (tree->last) {
 143                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 144                                  rb_node);
 145                 if (offset_in_entry(entry, file_offset))
 146                         return tree->last;
 147         }
 148         ret = __tree_search(root, file_offset, &prev);
 149         if (!ret)
 150                 ret = prev;
 151         if (ret)
 152                 tree->last = ret;
 153         return ret;
 154 }
 155
 156 /*
 157  * Allocate and add a new ordered_extent into the per-inode tree.
 158  *
 159  * The tree is given a single reference on the ordered extent that was
 160  * inserted.
 161  */
 162 static int __btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset,
 163                                       u64 disk_bytenr, u64 num_bytes,
 164                                       u64 disk_num_bytes, int type, int dio,
 165                                       int compress_type)
 166 {
 167         struct btrfs_root *root = inode->root;
 168         struct btrfs_fs_info *fs_info = root->fs_info;
 169         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 170         struct rb_node *node;
 171         struct btrfs_ordered_extent *entry;
 172         int ret;
 173
 174         if (type == BTRFS_ORDERED_NOCOW || type == BTRFS_ORDERED_PREALLOC) {
 175                 /* For nocow write, we can release the qgroup rsv right now */
 176                 ret = btrfs_qgroup_free_data(inode, NULL, file_offset, num_bytes);
 177                 if (ret < 0)
 178                         return ret;
 179                 ret = 0;
 180         } else {
 181                 /*
 182                  * The ordered extent has reserved qgroup space, release now
 183                  * and pass the reserved number for qgroup_record to free.
 184                  */
 185                 ret = btrfs_qgroup_release_data(inode, file_offset, num_bytes);
 186                 if (ret < 0)
 187                         return ret;
 188         }
 189         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 190         if (!entry)
 191                 return -ENOMEM;
 192
 193         entry->file_offset = file_offset;
 194         entry->disk_bytenr = disk_bytenr;
 195         entry->num_bytes = num_bytes;
 196         entry->disk_num_bytes = disk_num_bytes;
 197         entry->bytes_left = num_bytes;
 198         entry->inode = igrab(&inode->vfs_inode);
 199         entry->compress_type = compress_type;
 200         entry->truncated_len = (u64)-1;
 201         entry->qgroup_rsv = ret;
 202
 203         ASSERT(type == BTRFS_ORDERED_REGULAR ||
 204                type == BTRFS_ORDERED_NOCOW ||
 205                type == BTRFS_ORDERED_PREALLOC ||
 206                type == BTRFS_ORDERED_COMPRESSED);
 207         set_bit(type, &entry->flags);
 208
 209         if (dio) {
 210                 percpu_counter_add_batch(&fs_info->dio_bytes, num_bytes,
 211                                          fs_info->delalloc_batch);
 212                 set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 213         }
 214
 215         /* one ref for the tree */
 216         refcount_set(&entry->refs, 1);
 217         init_waitqueue_head(&entry->wait);
 218         INIT_LIST_HEAD(&entry->list);
 219         INIT_LIST_HEAD(&entry->log_list);
 220         INIT_LIST_HEAD(&entry->root_extent_list);
 221         INIT_LIST_HEAD(&entry->work_list);
 222         init_completion(&entry->completion);
 223
 224         trace_btrfs_ordered_extent_add(inode, entry);
 225
 226         spin_lock_irq(&tree->lock);
 227         node = tree_insert(&tree->tree, file_offset,
 228                            &entry->rb_node);
 229         if (node)
 230                 btrfs_panic(fs_info, -EEXIST,
 231                                 "inconsistency in ordered tree at offset %llu",
 232                                 file_offset);
 233         spin_unlock_irq(&tree->lock);
 234
 235         spin_lock(&root->ordered_extent_lock);
 236         list_add_tail(&entry->root_extent_list,
 237                       &root->ordered_extents);
 238         root->nr_ordered_extents++;
 239         if (root->nr_ordered_extents == 1) {
 240                 spin_lock(&fs_info->ordered_root_lock);
 241                 BUG_ON(!list_empty(&root->ordered_root));
 242                 list_add_tail(&root->ordered_root, &fs_info->ordered_roots);
 243                 spin_unlock(&fs_info->ordered_root_lock);
 244         }
 245         spin_unlock(&root->ordered_extent_lock);
 246
 247         /*
 248          * We don't need the count_max_extents here, we can assume that all of
 249          * that work has been done at higher layers, so this is truly the
 250          * smallest the extent is going to get.
 251          */
 252         spin_lock(&inode->lock);
 253         btrfs_mod_outstanding_extents(inode, 1);
 254         spin_unlock(&inode->lock);
 255
 256         return 0;
 257 }
 258
 259 int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset,
 260                              u64 disk_bytenr, u64 num_bytes, u64 disk_num_bytes,
 261                              int type)
 262 {
 263         ASSERT(type == BTRFS_ORDERED_REGULAR ||
 264                type == BTRFS_ORDERED_NOCOW ||
 265                type == BTRFS_ORDERED_PREALLOC);
 266         return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
 267                                           num_bytes, disk_num_bytes, type, 0,
 268                                           BTRFS_COMPRESS_NONE);
 269 }
 270
 271 int btrfs_add_ordered_extent_dio(struct btrfs_inode *inode, u64 file_offset,
 272                                  u64 disk_bytenr, u64 num_bytes,
 273                                  u64 disk_num_bytes, int type)
 274 {
 275         ASSERT(type == BTRFS_ORDERED_REGULAR ||
 276                type == BTRFS_ORDERED_NOCOW ||
 277                type == BTRFS_ORDERED_PREALLOC);
 278         return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
 279                                           num_bytes, disk_num_bytes, type, 1,
 280                                           BTRFS_COMPRESS_NONE);
 281 }
 282
 283 int btrfs_add_ordered_extent_compress(struct btrfs_inode *inode, u64 file_offset,
 284                                       u64 disk_bytenr, u64 num_bytes,
 285                                       u64 disk_num_bytes, int compress_type)
 286 {
 287         ASSERT(compress_type != BTRFS_COMPRESS_NONE);
 288         return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
 289                                           num_bytes, disk_num_bytes,
 290                                           BTRFS_ORDERED_COMPRESSED, 0,
 291                                           compress_type);
 292 }
 293
 294 /*
 295  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 296  * when an ordered extent is finished.  If the list covers more than one
 297  * ordered extent, it is split across multiples.
 298  */
 299 void btrfs_add_ordered_sum(struct btrfs_ordered_extent *entry,
 300                            struct btrfs_ordered_sum *sum)
 301 {
 302         struct btrfs_ordered_inode_tree *tree;
 303
 304         tree = &BTRFS_I(entry->inode)->ordered_tree;
 305         spin_lock_irq(&tree->lock);
 306         list_add_tail(&sum->list, &entry->list);
 307         spin_unlock_irq(&tree->lock);
 308 }
 309
 310 /*
 311  * Finish IO for one ordered extent across a given range.  The range can
 312  * contain several ordered extents.
 313  *
 314  * @found_ret:   Return the finished ordered extent
 315  * @file_offset: File offset for the finished IO
 316  *               Will also be updated to one byte past the range that is
 317  *               recordered as finished. This allows caller to walk forward.
 318  * @io_size:     Length of the finish IO range
 319  * @uptodate:    If the IO finished without problem
 320  *
 321  * Return true if any ordered extent is finished in the range, and update
 322  * @found_ret and @file_offset.
 323  * Return false otherwise.
 324  *
 325  * NOTE: Although The range can cross multiple ordered extents, only one
 326  * ordered extent will be updated during one call. The caller is responsible to
 327  * iterate all ordered extents in the range.
 328  */
 329 bool btrfs_dec_test_first_ordered_pending(struct btrfs_inode *inode,
 330                                    struct btrfs_ordered_extent **finished_ret,
 331                                    u64 *file_offset, u64 io_size, int uptodate)
 332 {
 333         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 334         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 335         struct rb_node *node;
 336         struct btrfs_ordered_extent *entry = NULL;
 337         bool finished = false;
 338         unsigned long flags;
 339         u64 dec_end;
 340         u64 dec_start;
 341         u64 to_dec;
 342
 343         spin_lock_irqsave(&tree->lock, flags);
 344         node = tree_search(tree, *file_offset);
 345         if (!node)
 346                 goto out;
 347
 348         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 349         if (!offset_in_entry(entry, *file_offset))
 350                 goto out;
 351
 352         dec_start = max(*file_offset, entry->file_offset);
 353         dec_end = min(*file_offset + io_size,
 354                       entry->file_offset + entry->num_bytes);
 355         *file_offset = dec_end;
 356         if (dec_start > dec_end) {
 357                 btrfs_crit(fs_info, "bad ordering dec_start %llu end %llu",
 358                            dec_start, dec_end);
 359         }
 360         to_dec = dec_end - dec_start;
 361         if (to_dec > entry->bytes_left) {
 362                 btrfs_crit(fs_info,
 363                            "bad ordered accounting left %llu size %llu",
 364                            entry->bytes_left, to_dec);
 365         }
 366         entry->bytes_left -= to_dec;
 367         if (!uptodate)
 368                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 369
 370         if (entry->bytes_left == 0) {
 371                 /*
 372                  * Ensure only one caller can set the flag and finished_ret
 373                  * accordingly
 374                  */
 375                 finished = !test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 376                 /* test_and_set_bit implies a barrier */
 377                 cond_wake_up_nomb(&entry->wait);
 378         }
 379 out:
 380         if (finished && finished_ret && entry) {
 381                 *finished_ret = entry;
 382                 refcount_inc(&entry->refs);
 383         }
 384         spin_unlock_irqrestore(&tree->lock, flags);
 385         return finished;
 386 }
 387
 388 /*
 389  * Finish IO for one ordered extent across a given range.  The range can only
 390  * contain one ordered extent.
 391  *
 392  * @cached:      The cached ordered extent. If not NULL, we can skip the tree
 393  *               search and use the ordered extent directly.
 394  *               Will be also used to store the finished ordered extent.
 395  * @file_offset: File offset for the finished IO
 396  * @io_size:     Length of the finish IO range
 397  * @uptodate:    If the IO finishes without problem
 398  *
 399  * Return true if the ordered extent is finished in the range, and update
 400  * @cached.
 401  * Return false otherwise.
 402  *
 403  * NOTE: The range can NOT cross multiple ordered extents.
 404  * Thus caller should ensure the range doesn't cross ordered extents.
 405  */
 406 bool btrfs_dec_test_ordered_pending(struct btrfs_inode *inode,
 407                                     struct btrfs_ordered_extent **cached,
 408                                     u64 file_offset, u64 io_size, int uptodate)
 409 {
 410         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 411         struct rb_node *node;
 412         struct btrfs_ordered_extent *entry = NULL;
 413         unsigned long flags;
 414         bool finished = false;
 415
 416         spin_lock_irqsave(&tree->lock, flags);
 417         if (cached && *cached) {
 418                 entry = *cached;
 419                 goto have_entry;
 420         }
 421
 422         node = tree_search(tree, file_offset);
 423         if (!node)
 424                 goto out;
 425
 426         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 427 have_entry:
 428         if (!offset_in_entry(entry, file_offset))
 429                 goto out;
 430
 431         if (io_size > entry->bytes_left)
 432                 btrfs_crit(inode->root->fs_info,
 433                            "bad ordered accounting left %llu size %llu",
 434                        entry->bytes_left, io_size);
 435
 436         entry->bytes_left -= io_size;
 437         if (!uptodate)
 438                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 439
 440         if (entry->bytes_left == 0) {
 441                 /*
 442                  * Ensure only one caller can set the flag and finished_ret
 443                  * accordingly
 444                  */
 445                 finished = !test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 446                 /* test_and_set_bit implies a barrier */
 447                 cond_wake_up_nomb(&entry->wait);
 448         }
 449 out:
 450         if (finished && cached && entry) {
 451                 *cached = entry;
 452                 refcount_inc(&entry->refs);
 453         }
 454         spin_unlock_irqrestore(&tree->lock, flags);
 455         return finished;
 456 }
 457
 458 /*
 459  * used to drop a reference on an ordered extent.  This will free
 460  * the extent if the last reference is dropped
 461  */
 462 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 463 {
 464         struct list_head *cur;
 465         struct btrfs_ordered_sum *sum;
 466
 467         trace_btrfs_ordered_extent_put(BTRFS_I(entry->inode), entry);
 468
 469         if (refcount_dec_and_test(&entry->refs)) {
 470                 ASSERT(list_empty(&entry->root_extent_list));
 471                 ASSERT(list_empty(&entry->log_list));
 472                 ASSERT(RB_EMPTY_NODE(&entry->rb_node));
 473                 if (entry->inode)
 474                         btrfs_add_delayed_iput(entry->inode);
 475                 while (!list_empty(&entry->list)) {
 476                         cur = entry->list.next;
 477                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 478                         list_del(&sum->list);
 479                         kvfree(sum);
 480                 }
 481                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 482         }
 483 }
 484
 485 /*
 486  * remove an ordered extent from the tree.  No references are dropped
 487  * and waiters are woken up.
 488  */
 489 void btrfs_remove_ordered_extent(struct btrfs_inode *btrfs_inode,
 490                                  struct btrfs_ordered_extent *entry)
 491 {
 492         struct btrfs_ordered_inode_tree *tree;
 493         struct btrfs_root *root = btrfs_inode->root;
 494         struct btrfs_fs_info *fs_info = root->fs_info;
 495         struct rb_node *node;
 496         bool pending;
 497
 498         /* This is paired with btrfs_add_ordered_extent. */
 499         spin_lock(&btrfs_inode->lock);
 500         btrfs_mod_outstanding_extents(btrfs_inode, -1);
 501         spin_unlock(&btrfs_inode->lock);
 502         if (root != fs_info->tree_root)
 503                 btrfs_delalloc_release_metadata(btrfs_inode, entry->num_bytes,
 504                                                 false);
 505
 506         if (test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 507                 percpu_counter_add_batch(&fs_info->dio_bytes, -entry->num_bytes,
 508                                          fs_info->delalloc_batch);
 509
 510         tree = &btrfs_inode->ordered_tree;
 511         spin_lock_irq(&tree->lock);
 512         node = &entry->rb_node;
 513         rb_erase(node, &tree->tree);
 514         RB_CLEAR_NODE(node);
 515         if (tree->last == node)
 516                 tree->last = NULL;
 517         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 518         pending = test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags);
 519         spin_unlock_irq(&tree->lock);
 520
 521         /*
 522          * The current running transaction is waiting on us, we need to let it
 523          * know that we're complete and wake it up.
 524          */
 525         if (pending) {
 526                 struct btrfs_transaction *trans;
 527
 528                 /*
 529                  * The checks for trans are just a formality, it should be set,
 530                  * but if it isn't we don't want to deref/assert under the spin
 531                  * lock, so be nice and check if trans is set, but ASSERT() so
 532                  * if it isn't set a developer will notice.
 533                  */
 534                 spin_lock(&fs_info->trans_lock);
 535                 trans = fs_info->running_transaction;
 536                 if (trans)
 537                         refcount_inc(&trans->use_count);
 538                 spin_unlock(&fs_info->trans_lock);
 539
 540                 ASSERT(trans);
 541                 if (trans) {
 542                         if (atomic_dec_and_test(&trans->pending_ordered))
 543                                 wake_up(&trans->pending_wait);
 544                         btrfs_put_transaction(trans);
 545                 }
 546         }
 547
 548         spin_lock(&root->ordered_extent_lock);
 549         list_del_init(&entry->root_extent_list);
 550         root->nr_ordered_extents--;
 551
 552         trace_btrfs_ordered_extent_remove(btrfs_inode, entry);
 553
 554         if (!root->nr_ordered_extents) {
 555                 spin_lock(&fs_info->ordered_root_lock);
 556                 BUG_ON(list_empty(&root->ordered_root));
 557                 list_del_init(&root->ordered_root);
 558                 spin_unlock(&fs_info->ordered_root_lock);
 559         }
 560         spin_unlock(&root->ordered_extent_lock);
 561         wake_up(&entry->wait);
 562 }
 563
 564 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 565 {
 566         struct btrfs_ordered_extent *ordered;
 567
 568         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 569         btrfs_start_ordered_extent(ordered, 1);
 570         complete(&ordered->completion);
 571 }
 572
 573 /*
 574  * wait for all the ordered extents in a root.  This is done when balancing
 575  * space between drives.
 576  */
 577 u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
 578                                const u64 range_start, const u64 range_len)
 579 {
 580         struct btrfs_fs_info *fs_info = root->fs_info;
 581         LIST_HEAD(splice);
 582         LIST_HEAD(skipped);
 583         LIST_HEAD(works);
 584         struct btrfs_ordered_extent *ordered, *next;
 585         u64 count = 0;
 586         const u64 range_end = range_start + range_len;
 587
 588         mutex_lock(&root->ordered_extent_mutex);
 589         spin_lock(&root->ordered_extent_lock);
 590         list_splice_init(&root->ordered_extents, &splice);
 591         while (!list_empty(&splice) && nr) {
 592                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 593                                            root_extent_list);
 594
 595                 if (range_end <= ordered->disk_bytenr ||
 596                     ordered->disk_bytenr + ordered->disk_num_bytes <= range_start) {
 597                         list_move_tail(&ordered->root_extent_list, &skipped);
 598                         cond_resched_lock(&root->ordered_extent_lock);
 599                         continue;
 600                 }
 601
 602                 list_move_tail(&ordered->root_extent_list,
 603                                &root->ordered_extents);
 604                 refcount_inc(&ordered->refs);
 605                 spin_unlock(&root->ordered_extent_lock);
 606
 607                 btrfs_init_work(&ordered->flush_work,
 608                                 btrfs_run_ordered_extent_work, NULL, NULL);
 609                 list_add_tail(&ordered->work_list, &works);
 610                 btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
 611
 612                 cond_resched();
 613                 spin_lock(&root->ordered_extent_lock);
 614                 if (nr != U64_MAX)
 615                         nr--;
 616                 count++;
 617         }
 618         list_splice_tail(&skipped, &root->ordered_extents);
 619         list_splice_tail(&splice, &root->ordered_extents);
 620         spin_unlock(&root->ordered_extent_lock);
 621
 622         list_for_each_entry_safe(ordered, next, &works, work_list) {
 623                 list_del_init(&ordered->work_list);
 624                 wait_for_completion(&ordered->completion);
 625                 btrfs_put_ordered_extent(ordered);
 626                 cond_resched();
 627         }
 628         mutex_unlock(&root->ordered_extent_mutex);
 629
 630         return count;
 631 }
 632
 633 void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
 634                              const u64 range_start, const u64 range_len)
 635 {
 636         struct btrfs_root *root;
 637         struct list_head splice;
 638         u64 done;
 639
 640         INIT_LIST_HEAD(&splice);
 641
 642         mutex_lock(&fs_info->ordered_operations_mutex);
 643         spin_lock(&fs_info->ordered_root_lock);
 644         list_splice_init(&fs_info->ordered_roots, &splice);
 645         while (!list_empty(&splice) && nr) {
 646                 root = list_first_entry(&splice, struct btrfs_root,
 647                                         ordered_root);
 648                 root = btrfs_grab_root(root);
 649                 BUG_ON(!root);
 650                 list_move_tail(&root->ordered_root,
 651                                &fs_info->ordered_roots);
 652                 spin_unlock(&fs_info->ordered_root_lock);
 653
 654                 done = btrfs_wait_ordered_extents(root, nr,
 655                                                   range_start, range_len);
 656                 btrfs_put_root(root);
 657
 658                 spin_lock(&fs_info->ordered_root_lock);
 659                 if (nr != U64_MAX) {
 660                         nr -= done;
 661                 }
 662         }
 663         list_splice_tail(&splice, &fs_info->ordered_roots);
 664         spin_unlock(&fs_info->ordered_root_lock);
 665         mutex_unlock(&fs_info->ordered_operations_mutex);
 666 }
 667
 668 /*
 669  * Used to start IO or wait for a given ordered extent to finish.
 670  *
 671  * If wait is one, this effectively waits on page writeback for all the pages
 672  * in the extent, and it waits on the io completion code to insert
 673  * metadata into the btree corresponding to the extent
 674  */
 675 void btrfs_start_ordered_extent(struct btrfs_ordered_extent *entry, int wait)
 676 {
 677         u64 start = entry->file_offset;
 678         u64 end = start + entry->num_bytes - 1;
 679         struct btrfs_inode *inode = BTRFS_I(entry->inode);
 680
 681         trace_btrfs_ordered_extent_start(inode, entry);
 682
 683         /*
 684          * pages in the range can be dirty, clean or writeback.  We
 685          * start IO on any dirty ones so the wait doesn't stall waiting
 686          * for the flusher thread to find them
 687          */
 688         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 689                 filemap_fdatawrite_range(inode->vfs_inode.i_mapping, start, end);
 690         if (wait) {
 691                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 692                                                  &entry->flags));
 693         }
 694 }
 695
 696 /*
 697  * Used to wait on ordered extents across a large range of bytes.
 698  */
 699 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 700 {
 701         int ret = 0;
 702         int ret_wb = 0;
 703         u64 end;
 704         u64 orig_end;
 705         struct btrfs_ordered_extent *ordered;
 706
 707         if (start + len < start) {
 708                 orig_end = INT_LIMIT(loff_t);
 709         } else {
 710                 orig_end = start + len - 1;
 711                 if (orig_end > INT_LIMIT(loff_t))
 712                         orig_end = INT_LIMIT(loff_t);
 713         }
 714
 715         /* start IO across the range first to instantiate any delalloc
 716          * extents
 717          */
 718         ret = btrfs_fdatawrite_range(inode, start, orig_end);
 719         if (ret)
 720                 return ret;
 721
 722         /*
 723          * If we have a writeback error don't return immediately. Wait first
 724          * for any ordered extents that haven't completed yet. This is to make
 725          * sure no one can dirty the same page ranges and call writepages()
 726          * before the ordered extents complete - to avoid failures (-EEXIST)
 727          * when adding the new ordered extents to the ordered tree.
 728          */
 729         ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 730
 731         end = orig_end;
 732         while (1) {
 733                 ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode), end);
 734                 if (!ordered)
 735                         break;
 736                 if (ordered->file_offset > orig_end) {
 737                         btrfs_put_ordered_extent(ordered);
 738                         break;
 739                 }
 740                 if (ordered->file_offset + ordered->num_bytes <= start) {
 741                         btrfs_put_ordered_extent(ordered);
 742                         break;
 743                 }
 744                 btrfs_start_ordered_extent(ordered, 1);
 745                 end = ordered->file_offset;
 746                 /*
 747                  * If the ordered extent had an error save the error but don't
 748                  * exit without waiting first for all other ordered extents in
 749                  * the range to complete.
 750                  */
 751                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 752                         ret = -EIO;
 753                 btrfs_put_ordered_extent(ordered);
 754                 if (end == 0 || end == start)
 755                         break;
 756                 end--;
 757         }
 758         return ret_wb ? ret_wb : ret;
 759 }
 760
 761 /*
 762  * find an ordered extent corresponding to file_offset.  return NULL if
 763  * nothing is found, otherwise take a reference on the extent and return it
 764  */
 765 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct btrfs_inode *inode,
 766                                                          u64 file_offset)
 767 {
 768         struct btrfs_ordered_inode_tree *tree;
 769         struct rb_node *node;
 770         struct btrfs_ordered_extent *entry = NULL;
 771
 772         tree = &inode->ordered_tree;
 773         spin_lock_irq(&tree->lock);
 774         node = tree_search(tree, file_offset);
 775         if (!node)
 776                 goto out;
 777
 778         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 779         if (!offset_in_entry(entry, file_offset))
 780                 entry = NULL;
 781         if (entry)
 782                 refcount_inc(&entry->refs);
 783 out:
 784         spin_unlock_irq(&tree->lock);
 785         return entry;
 786 }
 787
 788 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 789  * extents that exist in the range, rather than just the start of the range.
 790  */
 791 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
 792                 struct btrfs_inode *inode, u64 file_offset, u64 len)
 793 {
 794         struct btrfs_ordered_inode_tree *tree;
 795         struct rb_node *node;
 796         struct btrfs_ordered_extent *entry = NULL;
 797
 798         tree = &inode->ordered_tree;
 799         spin_lock_irq(&tree->lock);
 800         node = tree_search(tree, file_offset);
 801         if (!node) {
 802                 node = tree_search(tree, file_offset + len);
 803                 if (!node)
 804                         goto out;
 805         }
 806
 807         while (1) {
 808                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 809                 if (range_overlaps(entry, file_offset, len))
 810                         break;
 811
 812                 if (entry->file_offset >= file_offset + len) {
 813                         entry = NULL;
 814                         break;
 815                 }
 816                 entry = NULL;
 817                 node = rb_next(node);
 818                 if (!node)
 819                         break;
 820         }
 821 out:
 822         if (entry)
 823                 refcount_inc(&entry->refs);
 824         spin_unlock_irq(&tree->lock);
 825         return entry;
 826 }
 827
 828 /*
 829  * Adds all ordered extents to the given list. The list ends up sorted by the
 830  * file_offset of the ordered extents.
 831  */
 832 void btrfs_get_ordered_extents_for_logging(struct btrfs_inode *inode,
 833                                            struct list_head *list)
 834 {
 835         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 836         struct rb_node *n;
 837
 838         ASSERT(inode_is_locked(&inode->vfs_inode));
 839
 840         spin_lock_irq(&tree->lock);
 841         for (n = rb_first(&tree->tree); n; n = rb_next(n)) {
 842                 struct btrfs_ordered_extent *ordered;
 843
 844                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 845
 846                 if (test_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
 847                         continue;
 848
 849                 ASSERT(list_empty(&ordered->log_list));
 850                 list_add_tail(&ordered->log_list, list);
 851                 refcount_inc(&ordered->refs);
 852         }
 853         spin_unlock_irq(&tree->lock);
 854 }
 855
 856 /*
 857  * lookup and return any extent before 'file_offset'.  NULL is returned
 858  * if none is found
 859  */
 860 struct btrfs_ordered_extent *
 861 btrfs_lookup_first_ordered_extent(struct btrfs_inode *inode, u64 file_offset)
 862 {
 863         struct btrfs_ordered_inode_tree *tree;
 864         struct rb_node *node;
 865         struct btrfs_ordered_extent *entry = NULL;
 866
 867         tree = &inode->ordered_tree;
 868         spin_lock_irq(&tree->lock);
 869         node = tree_search(tree, file_offset);
 870         if (!node)
 871                 goto out;
 872
 873         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 874         refcount_inc(&entry->refs);
 875 out:
 876         spin_unlock_irq(&tree->lock);
 877         return entry;
 878 }
 879
 880 /*
 881  * btrfs_flush_ordered_range - Lock the passed range and ensures all pending
 882  * ordered extents in it are run to completion.
 883  *
 884  * @inode:        Inode whose ordered tree is to be searched
 885  * @start:        Beginning of range to flush
 886  * @end:          Last byte of range to lock
 887  * @cached_state: If passed, will return the extent state responsible for the
 888  * locked range. It's the caller's responsibility to free the cached state.
 889  *
 890  * This function always returns with the given range locked, ensuring after it's
 891  * called no order extent can be pending.
 892  */
 893 void btrfs_lock_and_flush_ordered_range(struct btrfs_inode *inode, u64 start,
 894                                         u64 end,
 895                                         struct extent_state **cached_state)
 896 {
 897         struct btrfs_ordered_extent *ordered;
 898         struct extent_state *cache = NULL;
 899         struct extent_state **cachedp = &cache;
 900
 901         if (cached_state)
 902                 cachedp = cached_state;
 903
 904         while (1) {
 905                 lock_extent_bits(&inode->io_tree, start, end, cachedp);
 906                 ordered = btrfs_lookup_ordered_range(inode, start,
 907                                                      end - start + 1);
 908                 if (!ordered) {
 909                         /*
 910                          * If no external cached_state has been passed then
 911                          * decrement the extra ref taken for cachedp since we
 912                          * aren't exposing it outside of this function
 913                          */
 914                         if (!cached_state)
 915                                 refcount_dec(&cache->refs);
 916                         break;
 917                 }
 918                 unlock_extent_cached(&inode->io_tree, start, end, cachedp);
 919                 btrfs_start_ordered_extent(ordered, 1);
 920                 btrfs_put_ordered_extent(ordered);
 921         }
 922 }
 923
 924 int __init ordered_data_init(void)
 925 {
 926         btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
 927                                      sizeof(struct btrfs_ordered_extent), 0,
 928                                      SLAB_MEM_SPREAD,
 929                                      NULL);
 930         if (!btrfs_ordered_extent_cache)
 931                 return -ENOMEM;
 932
 933         return 0;
 934 }
 935
 936 void __cold ordered_data_exit(void)
 937 {
 938         kmem_cache_destroy(btrfs_ordered_extent_cache);
 939 }