1 // SPDX-License-Identifier: GPL-2.0
3 #include <linux/bitops.h>
4 #include <linux/slab.h>
7 #include <linux/pagemap.h>
8 #include <linux/page-flags.h>
9 #include <linux/spinlock.h>
10 #include <linux/blkdev.h>
11 #include <linux/swap.h>
12 #include <linux/writeback.h>
13 #include <linux/pagevec.h>
14 #include <linux/prefetch.h>
15 #include <linux/cleancache.h>
17 #include "extent_io.h"
18 #include "extent-io-tree.h"
19 #include "extent_map.h"
21 #include "btrfs_inode.h"
23 #include "check-integrity.h"
25 #include "rcu-string.h"
30 #include "block-group.h"
32 static struct kmem_cache *extent_state_cache;
33 static struct kmem_cache *extent_buffer_cache;
34 static struct bio_set btrfs_bioset;
36 static inline bool extent_state_in_tree(const struct extent_state *state)
38 return !RB_EMPTY_NODE(&state->rb_node);
41 #ifdef CONFIG_BTRFS_DEBUG
42 static LIST_HEAD(states);
43 static DEFINE_SPINLOCK(leak_lock);
45 static inline void btrfs_leak_debug_add(spinlock_t *lock,
46 struct list_head *new,
47 struct list_head *head)
51 spin_lock_irqsave(lock, flags);
53 spin_unlock_irqrestore(lock, flags);
56 static inline void btrfs_leak_debug_del(spinlock_t *lock,
57 struct list_head *entry)
61 spin_lock_irqsave(lock, flags);
63 spin_unlock_irqrestore(lock, flags);
66 void btrfs_extent_buffer_leak_debug_check(struct btrfs_fs_info *fs_info)
68 struct extent_buffer *eb;
72 * If we didn't get into open_ctree our allocated_ebs will not be
73 * initialized, so just skip this.
75 if (!fs_info->allocated_ebs.next)
78 spin_lock_irqsave(&fs_info->eb_leak_lock, flags);
79 while (!list_empty(&fs_info->allocated_ebs)) {
80 eb = list_first_entry(&fs_info->allocated_ebs,
81 struct extent_buffer, leak_list);
83 "BTRFS: buffer leak start %llu len %lu refs %d bflags %lu owner %llu\n",
84 eb->start, eb->len, atomic_read(&eb->refs), eb->bflags,
85 btrfs_header_owner(eb));
86 list_del(&eb->leak_list);
87 kmem_cache_free(extent_buffer_cache, eb);
89 spin_unlock_irqrestore(&fs_info->eb_leak_lock, flags);
92 static inline void btrfs_extent_state_leak_debug_check(void)
94 struct extent_state *state;
96 while (!list_empty(&states)) {
97 state = list_entry(states.next, struct extent_state, leak_list);
98 pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
99 state->start, state->end, state->state,
100 extent_state_in_tree(state),
101 refcount_read(&state->refs));
102 list_del(&state->leak_list);
103 kmem_cache_free(extent_state_cache, state);
107 #define btrfs_debug_check_extent_io_range(tree, start, end) \
108 __btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
109 static inline void __btrfs_debug_check_extent_io_range(const char *caller,
110 struct extent_io_tree *tree, u64 start, u64 end)
112 struct inode *inode = tree->private_data;
115 if (!inode || !is_data_inode(inode))
118 isize = i_size_read(inode);
119 if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
120 btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
121 "%s: ino %llu isize %llu odd range [%llu,%llu]",
122 caller, btrfs_ino(BTRFS_I(inode)), isize, start, end);
126 #define btrfs_leak_debug_add(lock, new, head) do {} while (0)
127 #define btrfs_leak_debug_del(lock, entry) do {} while (0)
128 #define btrfs_extent_state_leak_debug_check() do {} while (0)
129 #define btrfs_debug_check_extent_io_range(c, s, e) do {} while (0)
135 struct rb_node rb_node;
138 struct extent_page_data {
140 /* tells writepage not to lock the state bits for this range
141 * it still does the unlocking
143 unsigned int extent_locked:1;
145 /* tells the submit_bio code to use REQ_SYNC */
146 unsigned int sync_io:1;
149 static int add_extent_changeset(struct extent_state *state, u32 bits,
150 struct extent_changeset *changeset,
157 if (set && (state->state & bits) == bits)
159 if (!set && (state->state & bits) == 0)
161 changeset->bytes_changed += state->end - state->start + 1;
162 ret = ulist_add(&changeset->range_changed, state->start, state->end,
167 int __must_check submit_one_bio(struct bio *bio, int mirror_num,
168 unsigned long bio_flags)
170 blk_status_t ret = 0;
171 struct extent_io_tree *tree = bio->bi_private;
173 bio->bi_private = NULL;
175 if (is_data_inode(tree->private_data))
176 ret = btrfs_submit_data_bio(tree->private_data, bio, mirror_num,
179 ret = btrfs_submit_metadata_bio(tree->private_data, bio,
180 mirror_num, bio_flags);
182 return blk_status_to_errno(ret);
185 /* Cleanup unsubmitted bios */
186 static void end_write_bio(struct extent_page_data *epd, int ret)
189 epd->bio->bi_status = errno_to_blk_status(ret);
196 * Submit bio from extent page data via submit_one_bio
198 * Return 0 if everything is OK.
199 * Return <0 for error.
201 static int __must_check flush_write_bio(struct extent_page_data *epd)
206 ret = submit_one_bio(epd->bio, 0, 0);
208 * Clean up of epd->bio is handled by its endio function.
209 * And endio is either triggered by successful bio execution
210 * or the error handler of submit bio hook.
211 * So at this point, no matter what happened, we don't need
212 * to clean up epd->bio.
219 int __init extent_state_cache_init(void)
221 extent_state_cache = kmem_cache_create("btrfs_extent_state",
222 sizeof(struct extent_state), 0,
223 SLAB_MEM_SPREAD, NULL);
224 if (!extent_state_cache)
229 int __init extent_io_init(void)
231 extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
232 sizeof(struct extent_buffer), 0,
233 SLAB_MEM_SPREAD, NULL);
234 if (!extent_buffer_cache)
237 if (bioset_init(&btrfs_bioset, BIO_POOL_SIZE,
238 offsetof(struct btrfs_io_bio, bio),
240 goto free_buffer_cache;
242 if (bioset_integrity_create(&btrfs_bioset, BIO_POOL_SIZE))
248 bioset_exit(&btrfs_bioset);
251 kmem_cache_destroy(extent_buffer_cache);
252 extent_buffer_cache = NULL;
256 void __cold extent_state_cache_exit(void)
258 btrfs_extent_state_leak_debug_check();
259 kmem_cache_destroy(extent_state_cache);
262 void __cold extent_io_exit(void)
265 * Make sure all delayed rcu free are flushed before we
269 kmem_cache_destroy(extent_buffer_cache);
270 bioset_exit(&btrfs_bioset);
274 * For the file_extent_tree, we want to hold the inode lock when we lookup and
275 * update the disk_i_size, but lockdep will complain because our io_tree we hold
276 * the tree lock and get the inode lock when setting delalloc. These two things
277 * are unrelated, so make a class for the file_extent_tree so we don't get the
278 * two locking patterns mixed up.
280 static struct lock_class_key file_extent_tree_class;
282 void extent_io_tree_init(struct btrfs_fs_info *fs_info,
283 struct extent_io_tree *tree, unsigned int owner,
286 tree->fs_info = fs_info;
287 tree->state = RB_ROOT;
288 tree->dirty_bytes = 0;
289 spin_lock_init(&tree->lock);
290 tree->private_data = private_data;
292 if (owner == IO_TREE_INODE_FILE_EXTENT)
293 lockdep_set_class(&tree->lock, &file_extent_tree_class);
296 void extent_io_tree_release(struct extent_io_tree *tree)
298 spin_lock(&tree->lock);
300 * Do a single barrier for the waitqueue_active check here, the state
301 * of the waitqueue should not change once extent_io_tree_release is
305 while (!RB_EMPTY_ROOT(&tree->state)) {
306 struct rb_node *node;
307 struct extent_state *state;
309 node = rb_first(&tree->state);
310 state = rb_entry(node, struct extent_state, rb_node);
311 rb_erase(&state->rb_node, &tree->state);
312 RB_CLEAR_NODE(&state->rb_node);
314 * btree io trees aren't supposed to have tasks waiting for
315 * changes in the flags of extent states ever.
317 ASSERT(!waitqueue_active(&state->wq));
318 free_extent_state(state);
320 cond_resched_lock(&tree->lock);
322 spin_unlock(&tree->lock);
325 static struct extent_state *alloc_extent_state(gfp_t mask)
327 struct extent_state *state;
330 * The given mask might be not appropriate for the slab allocator,
331 * drop the unsupported bits
333 mask &= ~(__GFP_DMA32|__GFP_HIGHMEM);
334 state = kmem_cache_alloc(extent_state_cache, mask);
338 state->failrec = NULL;
339 RB_CLEAR_NODE(&state->rb_node);
340 btrfs_leak_debug_add(&leak_lock, &state->leak_list, &states);
341 refcount_set(&state->refs, 1);
342 init_waitqueue_head(&state->wq);
343 trace_alloc_extent_state(state, mask, _RET_IP_);
347 void free_extent_state(struct extent_state *state)
351 if (refcount_dec_and_test(&state->refs)) {
352 WARN_ON(extent_state_in_tree(state));
353 btrfs_leak_debug_del(&leak_lock, &state->leak_list);
354 trace_free_extent_state(state, _RET_IP_);
355 kmem_cache_free(extent_state_cache, state);
359 static struct rb_node *tree_insert(struct rb_root *root,
360 struct rb_node *search_start,
362 struct rb_node *node,
363 struct rb_node ***p_in,
364 struct rb_node **parent_in)
367 struct rb_node *parent = NULL;
368 struct tree_entry *entry;
370 if (p_in && parent_in) {
376 p = search_start ? &search_start : &root->rb_node;
379 entry = rb_entry(parent, struct tree_entry, rb_node);
381 if (offset < entry->start)
383 else if (offset > entry->end)
390 rb_link_node(node, parent, p);
391 rb_insert_color(node, root);
396 * Search @tree for an entry that contains @offset. Such entry would have
397 * entry->start <= offset && entry->end >= offset.
399 * @tree: the tree to search
400 * @offset: offset that should fall within an entry in @tree
401 * @next_ret: pointer to the first entry whose range ends after @offset
402 * @prev_ret: pointer to the first entry whose range begins before @offset
403 * @p_ret: pointer where new node should be anchored (used when inserting an
405 * @parent_ret: points to entry which would have been the parent of the entry,
408 * This function returns a pointer to the entry that contains @offset byte
409 * address. If no such entry exists, then NULL is returned and the other
410 * pointer arguments to the function are filled, otherwise the found entry is
411 * returned and other pointers are left untouched.
413 static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
414 struct rb_node **next_ret,
415 struct rb_node **prev_ret,
416 struct rb_node ***p_ret,
417 struct rb_node **parent_ret)
419 struct rb_root *root = &tree->state;
420 struct rb_node **n = &root->rb_node;
421 struct rb_node *prev = NULL;
422 struct rb_node *orig_prev = NULL;
423 struct tree_entry *entry;
424 struct tree_entry *prev_entry = NULL;
428 entry = rb_entry(prev, struct tree_entry, rb_node);
431 if (offset < entry->start)
433 else if (offset > entry->end)
446 while (prev && offset > prev_entry->end) {
447 prev = rb_next(prev);
448 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
455 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
456 while (prev && offset < prev_entry->start) {
457 prev = rb_prev(prev);
458 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
465 static inline struct rb_node *
466 tree_search_for_insert(struct extent_io_tree *tree,
468 struct rb_node ***p_ret,
469 struct rb_node **parent_ret)
471 struct rb_node *next= NULL;
474 ret = __etree_search(tree, offset, &next, NULL, p_ret, parent_ret);
480 static inline struct rb_node *tree_search(struct extent_io_tree *tree,
483 return tree_search_for_insert(tree, offset, NULL, NULL);
487 * utility function to look for merge candidates inside a given range.
488 * Any extents with matching state are merged together into a single
489 * extent in the tree. Extents with EXTENT_IO in their state field
490 * are not merged because the end_io handlers need to be able to do
491 * operations on them without sleeping (or doing allocations/splits).
493 * This should be called with the tree lock held.
495 static void merge_state(struct extent_io_tree *tree,
496 struct extent_state *state)
498 struct extent_state *other;
499 struct rb_node *other_node;
501 if (state->state & (EXTENT_LOCKED | EXTENT_BOUNDARY))
504 other_node = rb_prev(&state->rb_node);
506 other = rb_entry(other_node, struct extent_state, rb_node);
507 if (other->end == state->start - 1 &&
508 other->state == state->state) {
509 if (tree->private_data &&
510 is_data_inode(tree->private_data))
511 btrfs_merge_delalloc_extent(tree->private_data,
513 state->start = other->start;
514 rb_erase(&other->rb_node, &tree->state);
515 RB_CLEAR_NODE(&other->rb_node);
516 free_extent_state(other);
519 other_node = rb_next(&state->rb_node);
521 other = rb_entry(other_node, struct extent_state, rb_node);
522 if (other->start == state->end + 1 &&
523 other->state == state->state) {
524 if (tree->private_data &&
525 is_data_inode(tree->private_data))
526 btrfs_merge_delalloc_extent(tree->private_data,
528 state->end = other->end;
529 rb_erase(&other->rb_node, &tree->state);
530 RB_CLEAR_NODE(&other->rb_node);
531 free_extent_state(other);
536 static void set_state_bits(struct extent_io_tree *tree,
537 struct extent_state *state, u32 *bits,
538 struct extent_changeset *changeset);
541 * insert an extent_state struct into the tree. 'bits' are set on the
542 * struct before it is inserted.
544 * This may return -EEXIST if the extent is already there, in which case the
545 * state struct is freed.
547 * The tree lock is not taken internally. This is a utility function and
548 * probably isn't what you want to call (see set/clear_extent_bit).
550 static int insert_state(struct extent_io_tree *tree,
551 struct extent_state *state, u64 start, u64 end,
553 struct rb_node **parent,
554 u32 *bits, struct extent_changeset *changeset)
556 struct rb_node *node;
559 btrfs_err(tree->fs_info,
560 "insert state: end < start %llu %llu", end, start);
563 state->start = start;
566 set_state_bits(tree, state, bits, changeset);
568 node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
570 struct extent_state *found;
571 found = rb_entry(node, struct extent_state, rb_node);
572 btrfs_err(tree->fs_info,
573 "found node %llu %llu on insert of %llu %llu",
574 found->start, found->end, start, end);
577 merge_state(tree, state);
582 * split a given extent state struct in two, inserting the preallocated
583 * struct 'prealloc' as the newly created second half. 'split' indicates an
584 * offset inside 'orig' where it should be split.
587 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
588 * are two extent state structs in the tree:
589 * prealloc: [orig->start, split - 1]
590 * orig: [ split, orig->end ]
592 * The tree locks are not taken by this function. They need to be held
595 static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
596 struct extent_state *prealloc, u64 split)
598 struct rb_node *node;
600 if (tree->private_data && is_data_inode(tree->private_data))
601 btrfs_split_delalloc_extent(tree->private_data, orig, split);
603 prealloc->start = orig->start;
604 prealloc->end = split - 1;
605 prealloc->state = orig->state;
608 node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
609 &prealloc->rb_node, NULL, NULL);
611 free_extent_state(prealloc);
617 static struct extent_state *next_state(struct extent_state *state)
619 struct rb_node *next = rb_next(&state->rb_node);
621 return rb_entry(next, struct extent_state, rb_node);
627 * utility function to clear some bits in an extent state struct.
628 * it will optionally wake up anyone waiting on this state (wake == 1).
630 * If no bits are set on the state struct after clearing things, the
631 * struct is freed and removed from the tree
633 static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
634 struct extent_state *state,
636 struct extent_changeset *changeset)
638 struct extent_state *next;
639 u32 bits_to_clear = *bits & ~EXTENT_CTLBITS;
642 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
643 u64 range = state->end - state->start + 1;
644 WARN_ON(range > tree->dirty_bytes);
645 tree->dirty_bytes -= range;
648 if (tree->private_data && is_data_inode(tree->private_data))
649 btrfs_clear_delalloc_extent(tree->private_data, state, bits);
651 ret = add_extent_changeset(state, bits_to_clear, changeset, 0);
653 state->state &= ~bits_to_clear;
656 if (state->state == 0) {
657 next = next_state(state);
658 if (extent_state_in_tree(state)) {
659 rb_erase(&state->rb_node, &tree->state);
660 RB_CLEAR_NODE(&state->rb_node);
661 free_extent_state(state);
666 merge_state(tree, state);
667 next = next_state(state);
672 static struct extent_state *
673 alloc_extent_state_atomic(struct extent_state *prealloc)
676 prealloc = alloc_extent_state(GFP_ATOMIC);
681 static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
683 btrfs_panic(tree->fs_info, err,
684 "locking error: extent tree was modified by another thread while locked");
688 * clear some bits on a range in the tree. This may require splitting
689 * or inserting elements in the tree, so the gfp mask is used to
690 * indicate which allocations or sleeping are allowed.
692 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
693 * the given range from the tree regardless of state (ie for truncate).
695 * the range [start, end] is inclusive.
697 * This takes the tree lock, and returns 0 on success and < 0 on error.
699 int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
700 u32 bits, int wake, int delete,
701 struct extent_state **cached_state,
702 gfp_t mask, struct extent_changeset *changeset)
704 struct extent_state *state;
705 struct extent_state *cached;
706 struct extent_state *prealloc = NULL;
707 struct rb_node *node;
712 btrfs_debug_check_extent_io_range(tree, start, end);
713 trace_btrfs_clear_extent_bit(tree, start, end - start + 1, bits);
715 if (bits & EXTENT_DELALLOC)
716 bits |= EXTENT_NORESERVE;
719 bits |= ~EXTENT_CTLBITS;
721 if (bits & (EXTENT_LOCKED | EXTENT_BOUNDARY))
724 if (!prealloc && gfpflags_allow_blocking(mask)) {
726 * Don't care for allocation failure here because we might end
727 * up not needing the pre-allocated extent state at all, which
728 * is the case if we only have in the tree extent states that
729 * cover our input range and don't cover too any other range.
730 * If we end up needing a new extent state we allocate it later.
732 prealloc = alloc_extent_state(mask);
735 spin_lock(&tree->lock);
737 cached = *cached_state;
740 *cached_state = NULL;
744 if (cached && extent_state_in_tree(cached) &&
745 cached->start <= start && cached->end > start) {
747 refcount_dec(&cached->refs);
752 free_extent_state(cached);
755 * this search will find the extents that end after
758 node = tree_search(tree, start);
761 state = rb_entry(node, struct extent_state, rb_node);
763 if (state->start > end)
765 WARN_ON(state->end < start);
766 last_end = state->end;
768 /* the state doesn't have the wanted bits, go ahead */
769 if (!(state->state & bits)) {
770 state = next_state(state);
775 * | ---- desired range ---- |
777 * | ------------- state -------------- |
779 * We need to split the extent we found, and may flip
780 * bits on second half.
782 * If the extent we found extends past our range, we
783 * just split and search again. It'll get split again
784 * the next time though.
786 * If the extent we found is inside our range, we clear
787 * the desired bit on it.
790 if (state->start < start) {
791 prealloc = alloc_extent_state_atomic(prealloc);
793 err = split_state(tree, state, prealloc, start);
795 extent_io_tree_panic(tree, err);
800 if (state->end <= end) {
801 state = clear_state_bit(tree, state, &bits, wake,
808 * | ---- desired range ---- |
810 * We need to split the extent, and clear the bit
813 if (state->start <= end && state->end > end) {
814 prealloc = alloc_extent_state_atomic(prealloc);
816 err = split_state(tree, state, prealloc, end + 1);
818 extent_io_tree_panic(tree, err);
823 clear_state_bit(tree, prealloc, &bits, wake, changeset);
829 state = clear_state_bit(tree, state, &bits, wake, changeset);
831 if (last_end == (u64)-1)
833 start = last_end + 1;
834 if (start <= end && state && !need_resched())
840 spin_unlock(&tree->lock);
841 if (gfpflags_allow_blocking(mask))
846 spin_unlock(&tree->lock);
848 free_extent_state(prealloc);
854 static void wait_on_state(struct extent_io_tree *tree,
855 struct extent_state *state)
856 __releases(tree->lock)
857 __acquires(tree->lock)
860 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
861 spin_unlock(&tree->lock);
863 spin_lock(&tree->lock);
864 finish_wait(&state->wq, &wait);
868 * waits for one or more bits to clear on a range in the state tree.
869 * The range [start, end] is inclusive.
870 * The tree lock is taken by this function
872 static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
875 struct extent_state *state;
876 struct rb_node *node;
878 btrfs_debug_check_extent_io_range(tree, start, end);
880 spin_lock(&tree->lock);
884 * this search will find all the extents that end after
887 node = tree_search(tree, start);
892 state = rb_entry(node, struct extent_state, rb_node);
894 if (state->start > end)
897 if (state->state & bits) {
898 start = state->start;
899 refcount_inc(&state->refs);
900 wait_on_state(tree, state);
901 free_extent_state(state);
904 start = state->end + 1;
909 if (!cond_resched_lock(&tree->lock)) {
910 node = rb_next(node);
915 spin_unlock(&tree->lock);
918 static void set_state_bits(struct extent_io_tree *tree,
919 struct extent_state *state,
920 u32 *bits, struct extent_changeset *changeset)
922 u32 bits_to_set = *bits & ~EXTENT_CTLBITS;
925 if (tree->private_data && is_data_inode(tree->private_data))
926 btrfs_set_delalloc_extent(tree->private_data, state, bits);
928 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
929 u64 range = state->end - state->start + 1;
930 tree->dirty_bytes += range;
932 ret = add_extent_changeset(state, bits_to_set, changeset, 1);
934 state->state |= bits_to_set;
937 static void cache_state_if_flags(struct extent_state *state,
938 struct extent_state **cached_ptr,
941 if (cached_ptr && !(*cached_ptr)) {
942 if (!flags || (state->state & flags)) {
944 refcount_inc(&state->refs);
949 static void cache_state(struct extent_state *state,
950 struct extent_state **cached_ptr)
952 return cache_state_if_flags(state, cached_ptr,
953 EXTENT_LOCKED | EXTENT_BOUNDARY);
957 * set some bits on a range in the tree. This may require allocations or
958 * sleeping, so the gfp mask is used to indicate what is allowed.
960 * If any of the exclusive bits are set, this will fail with -EEXIST if some
961 * part of the range already has the desired bits set. The start of the
962 * existing range is returned in failed_start in this case.
964 * [start, end] is inclusive This takes the tree lock.
966 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, u32 bits,
967 u32 exclusive_bits, u64 *failed_start,
968 struct extent_state **cached_state, gfp_t mask,
969 struct extent_changeset *changeset)
971 struct extent_state *state;
972 struct extent_state *prealloc = NULL;
973 struct rb_node *node;
975 struct rb_node *parent;
980 btrfs_debug_check_extent_io_range(tree, start, end);
981 trace_btrfs_set_extent_bit(tree, start, end - start + 1, bits);
984 ASSERT(failed_start);
986 ASSERT(failed_start == NULL);
988 if (!prealloc && gfpflags_allow_blocking(mask)) {
990 * Don't care for allocation failure here because we might end
991 * up not needing the pre-allocated extent state at all, which
992 * is the case if we only have in the tree extent states that
993 * cover our input range and don't cover too any other range.
994 * If we end up needing a new extent state we allocate it later.
996 prealloc = alloc_extent_state(mask);
999 spin_lock(&tree->lock);
1000 if (cached_state && *cached_state) {
1001 state = *cached_state;
1002 if (state->start <= start && state->end > start &&
1003 extent_state_in_tree(state)) {
1004 node = &state->rb_node;
1009 * this search will find all the extents that end after
1012 node = tree_search_for_insert(tree, start, &p, &parent);
1014 prealloc = alloc_extent_state_atomic(prealloc);
1016 err = insert_state(tree, prealloc, start, end,
1017 &p, &parent, &bits, changeset);
1019 extent_io_tree_panic(tree, err);
1021 cache_state(prealloc, cached_state);
1025 state = rb_entry(node, struct extent_state, rb_node);
1027 last_start = state->start;
1028 last_end = state->end;
1031 * | ---- desired range ---- |
1034 * Just lock what we found and keep going
1036 if (state->start == start && state->end <= end) {
1037 if (state->state & exclusive_bits) {
1038 *failed_start = state->start;
1043 set_state_bits(tree, state, &bits, changeset);
1044 cache_state(state, cached_state);
1045 merge_state(tree, state);
1046 if (last_end == (u64)-1)
1048 start = last_end + 1;
1049 state = next_state(state);
1050 if (start < end && state && state->start == start &&
1057 * | ---- desired range ---- |
1060 * | ------------- state -------------- |
1062 * We need to split the extent we found, and may flip bits on
1065 * If the extent we found extends past our
1066 * range, we just split and search again. It'll get split
1067 * again the next time though.
1069 * If the extent we found is inside our range, we set the
1070 * desired bit on it.
1072 if (state->start < start) {
1073 if (state->state & exclusive_bits) {
1074 *failed_start = start;
1080 * If this extent already has all the bits we want set, then
1081 * skip it, not necessary to split it or do anything with it.
1083 if ((state->state & bits) == bits) {
1084 start = state->end + 1;
1085 cache_state(state, cached_state);
1089 prealloc = alloc_extent_state_atomic(prealloc);
1091 err = split_state(tree, state, prealloc, start);
1093 extent_io_tree_panic(tree, err);
1098 if (state->end <= end) {
1099 set_state_bits(tree, state, &bits, changeset);
1100 cache_state(state, cached_state);
1101 merge_state(tree, state);
1102 if (last_end == (u64)-1)
1104 start = last_end + 1;
1105 state = next_state(state);
1106 if (start < end && state && state->start == start &&
1113 * | ---- desired range ---- |
1114 * | state | or | state |
1116 * There's a hole, we need to insert something in it and
1117 * ignore the extent we found.
1119 if (state->start > start) {
1121 if (end < last_start)
1124 this_end = last_start - 1;
1126 prealloc = alloc_extent_state_atomic(prealloc);
1130 * Avoid to free 'prealloc' if it can be merged with
1133 err = insert_state(tree, prealloc, start, this_end,
1134 NULL, NULL, &bits, changeset);
1136 extent_io_tree_panic(tree, err);
1138 cache_state(prealloc, cached_state);
1140 start = this_end + 1;
1144 * | ---- desired range ---- |
1146 * We need to split the extent, and set the bit
1149 if (state->start <= end && state->end > end) {
1150 if (state->state & exclusive_bits) {
1151 *failed_start = start;
1156 prealloc = alloc_extent_state_atomic(prealloc);
1158 err = split_state(tree, state, prealloc, end + 1);
1160 extent_io_tree_panic(tree, err);
1162 set_state_bits(tree, prealloc, &bits, changeset);
1163 cache_state(prealloc, cached_state);
1164 merge_state(tree, prealloc);
1172 spin_unlock(&tree->lock);
1173 if (gfpflags_allow_blocking(mask))
1178 spin_unlock(&tree->lock);
1180 free_extent_state(prealloc);
1187 * convert_extent_bit - convert all bits in a given range from one bit to
1189 * @tree: the io tree to search
1190 * @start: the start offset in bytes
1191 * @end: the end offset in bytes (inclusive)
1192 * @bits: the bits to set in this range
1193 * @clear_bits: the bits to clear in this range
1194 * @cached_state: state that we're going to cache
1196 * This will go through and set bits for the given range. If any states exist
1197 * already in this range they are set with the given bit and cleared of the
1198 * clear_bits. This is only meant to be used by things that are mergeable, ie
1199 * converting from say DELALLOC to DIRTY. This is not meant to be used with
1200 * boundary bits like LOCK.
1202 * All allocations are done with GFP_NOFS.
1204 int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1205 u32 bits, u32 clear_bits,
1206 struct extent_state **cached_state)
1208 struct extent_state *state;
1209 struct extent_state *prealloc = NULL;
1210 struct rb_node *node;
1212 struct rb_node *parent;
1216 bool first_iteration = true;
1218 btrfs_debug_check_extent_io_range(tree, start, end);
1219 trace_btrfs_convert_extent_bit(tree, start, end - start + 1, bits,
1225 * Best effort, don't worry if extent state allocation fails
1226 * here for the first iteration. We might have a cached state
1227 * that matches exactly the target range, in which case no
1228 * extent state allocations are needed. We'll only know this
1229 * after locking the tree.
1231 prealloc = alloc_extent_state(GFP_NOFS);
1232 if (!prealloc && !first_iteration)
1236 spin_lock(&tree->lock);
1237 if (cached_state && *cached_state) {
1238 state = *cached_state;
1239 if (state->start <= start && state->end > start &&
1240 extent_state_in_tree(state)) {
1241 node = &state->rb_node;
1247 * this search will find all the extents that end after
1250 node = tree_search_for_insert(tree, start, &p, &parent);
1252 prealloc = alloc_extent_state_atomic(prealloc);
1257 err = insert_state(tree, prealloc, start, end,
1258 &p, &parent, &bits, NULL);
1260 extent_io_tree_panic(tree, err);
1261 cache_state(prealloc, cached_state);
1265 state = rb_entry(node, struct extent_state, rb_node);
1267 last_start = state->start;
1268 last_end = state->end;
1271 * | ---- desired range ---- |
1274 * Just lock what we found and keep going
1276 if (state->start == start && state->end <= end) {
1277 set_state_bits(tree, state, &bits, NULL);
1278 cache_state(state, cached_state);
1279 state = clear_state_bit(tree, state, &clear_bits, 0, NULL);
1280 if (last_end == (u64)-1)
1282 start = last_end + 1;
1283 if (start < end && state && state->start == start &&
1290 * | ---- desired range ---- |
1293 * | ------------- state -------------- |
1295 * We need to split the extent we found, and may flip bits on
1298 * If the extent we found extends past our
1299 * range, we just split and search again. It'll get split
1300 * again the next time though.
1302 * If the extent we found is inside our range, we set the
1303 * desired bit on it.
1305 if (state->start < start) {
1306 prealloc = alloc_extent_state_atomic(prealloc);
1311 err = split_state(tree, state, prealloc, start);
1313 extent_io_tree_panic(tree, err);
1317 if (state->end <= end) {
1318 set_state_bits(tree, state, &bits, NULL);
1319 cache_state(state, cached_state);
1320 state = clear_state_bit(tree, state, &clear_bits, 0,
1322 if (last_end == (u64)-1)
1324 start = last_end + 1;
1325 if (start < end && state && state->start == start &&
1332 * | ---- desired range ---- |
1333 * | state | or | state |
1335 * There's a hole, we need to insert something in it and
1336 * ignore the extent we found.
1338 if (state->start > start) {
1340 if (end < last_start)
1343 this_end = last_start - 1;
1345 prealloc = alloc_extent_state_atomic(prealloc);
1352 * Avoid to free 'prealloc' if it can be merged with
1355 err = insert_state(tree, prealloc, start, this_end,
1356 NULL, NULL, &bits, NULL);
1358 extent_io_tree_panic(tree, err);
1359 cache_state(prealloc, cached_state);
1361 start = this_end + 1;
1365 * | ---- desired range ---- |
1367 * We need to split the extent, and set the bit
1370 if (state->start <= end && state->end > end) {
1371 prealloc = alloc_extent_state_atomic(prealloc);
1377 err = split_state(tree, state, prealloc, end + 1);
1379 extent_io_tree_panic(tree, err);
1381 set_state_bits(tree, prealloc, &bits, NULL);
1382 cache_state(prealloc, cached_state);
1383 clear_state_bit(tree, prealloc, &clear_bits, 0, NULL);
1391 spin_unlock(&tree->lock);
1393 first_iteration = false;
1397 spin_unlock(&tree->lock);
1399 free_extent_state(prealloc);
1404 /* wrappers around set/clear extent bit */
1405 int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1406 u32 bits, struct extent_changeset *changeset)
1409 * We don't support EXTENT_LOCKED yet, as current changeset will
1410 * record any bits changed, so for EXTENT_LOCKED case, it will
1411 * either fail with -EEXIST or changeset will record the whole
1414 BUG_ON(bits & EXTENT_LOCKED);
1416 return set_extent_bit(tree, start, end, bits, 0, NULL, NULL, GFP_NOFS,
1420 int set_extent_bits_nowait(struct extent_io_tree *tree, u64 start, u64 end,
1423 return set_extent_bit(tree, start, end, bits, 0, NULL, NULL,
1427 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1428 u32 bits, int wake, int delete,
1429 struct extent_state **cached)
1431 return __clear_extent_bit(tree, start, end, bits, wake, delete,
1432 cached, GFP_NOFS, NULL);
1435 int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1436 u32 bits, struct extent_changeset *changeset)
1439 * Don't support EXTENT_LOCKED case, same reason as
1440 * set_record_extent_bits().
1442 BUG_ON(bits & EXTENT_LOCKED);
1444 return __clear_extent_bit(tree, start, end, bits, 0, 0, NULL, GFP_NOFS,
1449 * either insert or lock state struct between start and end use mask to tell
1450 * us if waiting is desired.
1452 int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1453 struct extent_state **cached_state)
1459 err = set_extent_bit(tree, start, end, EXTENT_LOCKED,
1460 EXTENT_LOCKED, &failed_start,
1461 cached_state, GFP_NOFS, NULL);
1462 if (err == -EEXIST) {
1463 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
1464 start = failed_start;
1467 WARN_ON(start > end);
1472 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1477 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1478 &failed_start, NULL, GFP_NOFS, NULL);
1479 if (err == -EEXIST) {
1480 if (failed_start > start)
1481 clear_extent_bit(tree, start, failed_start - 1,
1482 EXTENT_LOCKED, 1, 0, NULL);
1488 void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
1490 unsigned long index = start >> PAGE_SHIFT;
1491 unsigned long end_index = end >> PAGE_SHIFT;
1494 while (index <= end_index) {
1495 page = find_get_page(inode->i_mapping, index);
1496 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1497 clear_page_dirty_for_io(page);
1503 void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
1505 unsigned long index = start >> PAGE_SHIFT;
1506 unsigned long end_index = end >> PAGE_SHIFT;
1509 while (index <= end_index) {
1510 page = find_get_page(inode->i_mapping, index);
1511 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1512 __set_page_dirty_nobuffers(page);
1513 account_page_redirty(page);
1519 /* find the first state struct with 'bits' set after 'start', and
1520 * return it. tree->lock must be held. NULL will returned if
1521 * nothing was found after 'start'
1523 static struct extent_state *
1524 find_first_extent_bit_state(struct extent_io_tree *tree, u64 start, u32 bits)
1526 struct rb_node *node;
1527 struct extent_state *state;
1530 * this search will find all the extents that end after
1533 node = tree_search(tree, start);
1538 state = rb_entry(node, struct extent_state, rb_node);
1539 if (state->end >= start && (state->state & bits))
1542 node = rb_next(node);
1551 * Find the first offset in the io tree with one or more @bits set.
1553 * Note: If there are multiple bits set in @bits, any of them will match.
1555 * Return 0 if we find something, and update @start_ret and @end_ret.
1556 * Return 1 if we found nothing.
1558 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1559 u64 *start_ret, u64 *end_ret, u32 bits,
1560 struct extent_state **cached_state)
1562 struct extent_state *state;
1565 spin_lock(&tree->lock);
1566 if (cached_state && *cached_state) {
1567 state = *cached_state;
1568 if (state->end == start - 1 && extent_state_in_tree(state)) {
1569 while ((state = next_state(state)) != NULL) {
1570 if (state->state & bits)
1573 free_extent_state(*cached_state);
1574 *cached_state = NULL;
1577 free_extent_state(*cached_state);
1578 *cached_state = NULL;
1581 state = find_first_extent_bit_state(tree, start, bits);
1584 cache_state_if_flags(state, cached_state, 0);
1585 *start_ret = state->start;
1586 *end_ret = state->end;
1590 spin_unlock(&tree->lock);
1595 * Find a contiguous area of bits
1597 * @tree: io tree to check
1598 * @start: offset to start the search from
1599 * @start_ret: the first offset we found with the bits set
1600 * @end_ret: the final contiguous range of the bits that were set
1601 * @bits: bits to look for
1603 * set_extent_bit and clear_extent_bit can temporarily split contiguous ranges
1604 * to set bits appropriately, and then merge them again. During this time it
1605 * will drop the tree->lock, so use this helper if you want to find the actual
1606 * contiguous area for given bits. We will search to the first bit we find, and
1607 * then walk down the tree until we find a non-contiguous area. The area
1608 * returned will be the full contiguous area with the bits set.
1610 int find_contiguous_extent_bit(struct extent_io_tree *tree, u64 start,
1611 u64 *start_ret, u64 *end_ret, u32 bits)
1613 struct extent_state *state;
1616 spin_lock(&tree->lock);
1617 state = find_first_extent_bit_state(tree, start, bits);
1619 *start_ret = state->start;
1620 *end_ret = state->end;
1621 while ((state = next_state(state)) != NULL) {
1622 if (state->start > (*end_ret + 1))
1624 *end_ret = state->end;
1628 spin_unlock(&tree->lock);
1633 * Find the first range that has @bits not set. This range could start before
1636 * @tree: the tree to search
1637 * @start: offset at/after which the found extent should start
1638 * @start_ret: records the beginning of the range
1639 * @end_ret: records the end of the range (inclusive)
1640 * @bits: the set of bits which must be unset
1642 * Since unallocated range is also considered one which doesn't have the bits
1643 * set it's possible that @end_ret contains -1, this happens in case the range
1644 * spans (last_range_end, end of device]. In this case it's up to the caller to
1645 * trim @end_ret to the appropriate size.
1647 void find_first_clear_extent_bit(struct extent_io_tree *tree, u64 start,
1648 u64 *start_ret, u64 *end_ret, u32 bits)
1650 struct extent_state *state;
1651 struct rb_node *node, *prev = NULL, *next;
1653 spin_lock(&tree->lock);
1655 /* Find first extent with bits cleared */
1657 node = __etree_search(tree, start, &next, &prev, NULL, NULL);
1658 if (!node && !next && !prev) {
1660 * Tree is completely empty, send full range and let
1661 * caller deal with it
1666 } else if (!node && !next) {
1668 * We are past the last allocated chunk, set start at
1669 * the end of the last extent.
1671 state = rb_entry(prev, struct extent_state, rb_node);
1672 *start_ret = state->end + 1;
1679 * At this point 'node' either contains 'start' or start is
1682 state = rb_entry(node, struct extent_state, rb_node);
1684 if (in_range(start, state->start, state->end - state->start + 1)) {
1685 if (state->state & bits) {
1687 * |--range with bits sets--|
1691 start = state->end + 1;
1694 * 'start' falls within a range that doesn't
1695 * have the bits set, so take its start as
1696 * the beginning of the desired range
1698 * |--range with bits cleared----|
1702 *start_ret = state->start;
1707 * |---prev range---|---hole/unset---|---node range---|
1713 * |---hole/unset--||--first node--|
1718 state = rb_entry(prev, struct extent_state,
1720 *start_ret = state->end + 1;
1729 * Find the longest stretch from start until an entry which has the
1733 state = rb_entry(node, struct extent_state, rb_node);
1734 if (state->end >= start && !(state->state & bits)) {
1735 *end_ret = state->end;
1737 *end_ret = state->start - 1;
1741 node = rb_next(node);
1746 spin_unlock(&tree->lock);
1750 * find a contiguous range of bytes in the file marked as delalloc, not
1751 * more than 'max_bytes'. start and end are used to return the range,
1753 * true is returned if we find something, false if nothing was in the tree
1755 bool btrfs_find_delalloc_range(struct extent_io_tree *tree, u64 *start,
1756 u64 *end, u64 max_bytes,
1757 struct extent_state **cached_state)
1759 struct rb_node *node;
1760 struct extent_state *state;
1761 u64 cur_start = *start;
1763 u64 total_bytes = 0;
1765 spin_lock(&tree->lock);
1768 * this search will find all the extents that end after
1771 node = tree_search(tree, cur_start);
1778 state = rb_entry(node, struct extent_state, rb_node);
1779 if (found && (state->start != cur_start ||
1780 (state->state & EXTENT_BOUNDARY))) {
1783 if (!(state->state & EXTENT_DELALLOC)) {
1789 *start = state->start;
1790 *cached_state = state;
1791 refcount_inc(&state->refs);
1795 cur_start = state->end + 1;
1796 node = rb_next(node);
1797 total_bytes += state->end - state->start + 1;
1798 if (total_bytes >= max_bytes)
1804 spin_unlock(&tree->lock);
1808 static int __process_pages_contig(struct address_space *mapping,
1809 struct page *locked_page,
1810 pgoff_t start_index, pgoff_t end_index,
1811 unsigned long page_ops, pgoff_t *index_ret);
1813 static noinline void __unlock_for_delalloc(struct inode *inode,
1814 struct page *locked_page,
1817 unsigned long index = start >> PAGE_SHIFT;
1818 unsigned long end_index = end >> PAGE_SHIFT;
1820 ASSERT(locked_page);
1821 if (index == locked_page->index && end_index == index)
1824 __process_pages_contig(inode->i_mapping, locked_page, index, end_index,
1828 static noinline int lock_delalloc_pages(struct inode *inode,
1829 struct page *locked_page,
1833 unsigned long index = delalloc_start >> PAGE_SHIFT;
1834 unsigned long index_ret = index;
1835 unsigned long end_index = delalloc_end >> PAGE_SHIFT;
1838 ASSERT(locked_page);
1839 if (index == locked_page->index && index == end_index)
1842 ret = __process_pages_contig(inode->i_mapping, locked_page, index,
1843 end_index, PAGE_LOCK, &index_ret);
1845 __unlock_for_delalloc(inode, locked_page, delalloc_start,
1846 (u64)index_ret << PAGE_SHIFT);
1851 * Find and lock a contiguous range of bytes in the file marked as delalloc, no
1852 * more than @max_bytes. @Start and @end are used to return the range,
1854 * Return: true if we find something
1855 * false if nothing was in the tree
1858 noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
1859 struct page *locked_page, u64 *start,
1862 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
1863 u64 max_bytes = BTRFS_MAX_EXTENT_SIZE;
1867 struct extent_state *cached_state = NULL;
1872 /* step one, find a bunch of delalloc bytes starting at start */
1873 delalloc_start = *start;
1875 found = btrfs_find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1876 max_bytes, &cached_state);
1877 if (!found || delalloc_end <= *start) {
1878 *start = delalloc_start;
1879 *end = delalloc_end;
1880 free_extent_state(cached_state);
1885 * start comes from the offset of locked_page. We have to lock
1886 * pages in order, so we can't process delalloc bytes before
1889 if (delalloc_start < *start)
1890 delalloc_start = *start;
1893 * make sure to limit the number of pages we try to lock down
1895 if (delalloc_end + 1 - delalloc_start > max_bytes)
1896 delalloc_end = delalloc_start + max_bytes - 1;
1898 /* step two, lock all the pages after the page that has start */
1899 ret = lock_delalloc_pages(inode, locked_page,
1900 delalloc_start, delalloc_end);
1901 ASSERT(!ret || ret == -EAGAIN);
1902 if (ret == -EAGAIN) {
1903 /* some of the pages are gone, lets avoid looping by
1904 * shortening the size of the delalloc range we're searching
1906 free_extent_state(cached_state);
1907 cached_state = NULL;
1909 max_bytes = PAGE_SIZE;
1918 /* step three, lock the state bits for the whole range */
1919 lock_extent_bits(tree, delalloc_start, delalloc_end, &cached_state);
1921 /* then test to make sure it is all still delalloc */
1922 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1923 EXTENT_DELALLOC, 1, cached_state);
1925 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1927 __unlock_for_delalloc(inode, locked_page,
1928 delalloc_start, delalloc_end);
1932 free_extent_state(cached_state);
1933 *start = delalloc_start;
1934 *end = delalloc_end;
1939 static int __process_pages_contig(struct address_space *mapping,
1940 struct page *locked_page,
1941 pgoff_t start_index, pgoff_t end_index,
1942 unsigned long page_ops, pgoff_t *index_ret)
1944 unsigned long nr_pages = end_index - start_index + 1;
1945 unsigned long pages_processed = 0;
1946 pgoff_t index = start_index;
1947 struct page *pages[16];
1952 if (page_ops & PAGE_LOCK) {
1953 ASSERT(page_ops == PAGE_LOCK);
1954 ASSERT(index_ret && *index_ret == start_index);
1957 if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
1958 mapping_set_error(mapping, -EIO);
1960 while (nr_pages > 0) {
1961 ret = find_get_pages_contig(mapping, index,
1962 min_t(unsigned long,
1963 nr_pages, ARRAY_SIZE(pages)), pages);
1966 * Only if we're going to lock these pages,
1967 * can we find nothing at @index.
1969 ASSERT(page_ops & PAGE_LOCK);
1974 for (i = 0; i < ret; i++) {
1975 if (page_ops & PAGE_SET_PRIVATE2)
1976 SetPagePrivate2(pages[i]);
1978 if (locked_page && pages[i] == locked_page) {
1983 if (page_ops & PAGE_START_WRITEBACK) {
1984 clear_page_dirty_for_io(pages[i]);
1985 set_page_writeback(pages[i]);
1987 if (page_ops & PAGE_SET_ERROR)
1988 SetPageError(pages[i]);
1989 if (page_ops & PAGE_END_WRITEBACK)
1990 end_page_writeback(pages[i]);
1991 if (page_ops & PAGE_UNLOCK)
1992 unlock_page(pages[i]);
1993 if (page_ops & PAGE_LOCK) {
1994 lock_page(pages[i]);
1995 if (!PageDirty(pages[i]) ||
1996 pages[i]->mapping != mapping) {
1997 unlock_page(pages[i]);
1998 for (; i < ret; i++)
2012 if (err && index_ret)
2013 *index_ret = start_index + pages_processed - 1;
2017 void extent_clear_unlock_delalloc(struct btrfs_inode *inode, u64 start, u64 end,
2018 struct page *locked_page,
2019 u32 clear_bits, unsigned long page_ops)
2021 clear_extent_bit(&inode->io_tree, start, end, clear_bits, 1, 0, NULL);
2023 __process_pages_contig(inode->vfs_inode.i_mapping, locked_page,
2024 start >> PAGE_SHIFT, end >> PAGE_SHIFT,
2029 * count the number of bytes in the tree that have a given bit(s)
2030 * set. This can be fairly slow, except for EXTENT_DIRTY which is
2031 * cached. The total number found is returned.
2033 u64 count_range_bits(struct extent_io_tree *tree,
2034 u64 *start, u64 search_end, u64 max_bytes,
2035 u32 bits, int contig)
2037 struct rb_node *node;
2038 struct extent_state *state;
2039 u64 cur_start = *start;
2040 u64 total_bytes = 0;
2044 if (WARN_ON(search_end <= cur_start))
2047 spin_lock(&tree->lock);
2048 if (cur_start == 0 && bits == EXTENT_DIRTY) {
2049 total_bytes = tree->dirty_bytes;
2053 * this search will find all the extents that end after
2056 node = tree_search(tree, cur_start);
2061 state = rb_entry(node, struct extent_state, rb_node);
2062 if (state->start > search_end)
2064 if (contig && found && state->start > last + 1)
2066 if (state->end >= cur_start && (state->state & bits) == bits) {
2067 total_bytes += min(search_end, state->end) + 1 -
2068 max(cur_start, state->start);
2069 if (total_bytes >= max_bytes)
2072 *start = max(cur_start, state->start);
2076 } else if (contig && found) {
2079 node = rb_next(node);
2084 spin_unlock(&tree->lock);
2089 * set the private field for a given byte offset in the tree. If there isn't
2090 * an extent_state there already, this does nothing.
2092 int set_state_failrec(struct extent_io_tree *tree, u64 start,
2093 struct io_failure_record *failrec)
2095 struct rb_node *node;
2096 struct extent_state *state;
2099 spin_lock(&tree->lock);
2101 * this search will find all the extents that end after
2104 node = tree_search(tree, start);
2109 state = rb_entry(node, struct extent_state, rb_node);
2110 if (state->start != start) {
2114 state->failrec = failrec;
2116 spin_unlock(&tree->lock);
2120 struct io_failure_record *get_state_failrec(struct extent_io_tree *tree, u64 start)
2122 struct rb_node *node;
2123 struct extent_state *state;
2124 struct io_failure_record *failrec;
2126 spin_lock(&tree->lock);
2128 * this search will find all the extents that end after
2131 node = tree_search(tree, start);
2133 failrec = ERR_PTR(-ENOENT);
2136 state = rb_entry(node, struct extent_state, rb_node);
2137 if (state->start != start) {
2138 failrec = ERR_PTR(-ENOENT);
2142 failrec = state->failrec;
2144 spin_unlock(&tree->lock);
2149 * searches a range in the state tree for a given mask.
2150 * If 'filled' == 1, this returns 1 only if every extent in the tree
2151 * has the bits set. Otherwise, 1 is returned if any bit in the
2152 * range is found set.
2154 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
2155 u32 bits, int filled, struct extent_state *cached)
2157 struct extent_state *state = NULL;
2158 struct rb_node *node;
2161 spin_lock(&tree->lock);
2162 if (cached && extent_state_in_tree(cached) && cached->start <= start &&
2163 cached->end > start)
2164 node = &cached->rb_node;
2166 node = tree_search(tree, start);
2167 while (node && start <= end) {
2168 state = rb_entry(node, struct extent_state, rb_node);
2170 if (filled && state->start > start) {
2175 if (state->start > end)
2178 if (state->state & bits) {
2182 } else if (filled) {
2187 if (state->end == (u64)-1)
2190 start = state->end + 1;
2193 node = rb_next(node);
2200 spin_unlock(&tree->lock);
2205 * helper function to set a given page up to date if all the
2206 * extents in the tree for that page are up to date
2208 static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
2210 u64 start = page_offset(page);
2211 u64 end = start + PAGE_SIZE - 1;
2212 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
2213 SetPageUptodate(page);
2216 int free_io_failure(struct extent_io_tree *failure_tree,
2217 struct extent_io_tree *io_tree,
2218 struct io_failure_record *rec)
2223 set_state_failrec(failure_tree, rec->start, NULL);
2224 ret = clear_extent_bits(failure_tree, rec->start,
2225 rec->start + rec->len - 1,
2226 EXTENT_LOCKED | EXTENT_DIRTY);
2230 ret = clear_extent_bits(io_tree, rec->start,
2231 rec->start + rec->len - 1,
2241 * this bypasses the standard btrfs submit functions deliberately, as
2242 * the standard behavior is to write all copies in a raid setup. here we only
2243 * want to write the one bad copy. so we do the mapping for ourselves and issue
2244 * submit_bio directly.
2245 * to avoid any synchronization issues, wait for the data after writing, which
2246 * actually prevents the read that triggered the error from finishing.
2247 * currently, there can be no more than two copies of every data bit. thus,
2248 * exactly one rewrite is required.
2250 int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
2251 u64 length, u64 logical, struct page *page,
2252 unsigned int pg_offset, int mirror_num)
2255 struct btrfs_device *dev;
2258 struct btrfs_bio *bbio = NULL;
2261 ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
2262 BUG_ON(!mirror_num);
2264 if (btrfs_is_zoned(fs_info))
2265 return btrfs_repair_one_zone(fs_info, logical);
2267 bio = btrfs_io_bio_alloc(1);
2268 bio->bi_iter.bi_size = 0;
2269 map_length = length;
2272 * Avoid races with device replace and make sure our bbio has devices
2273 * associated to its stripes that don't go away while we are doing the
2274 * read repair operation.
2276 btrfs_bio_counter_inc_blocked(fs_info);
2277 if (btrfs_is_parity_mirror(fs_info, logical, length)) {
2279 * Note that we don't use BTRFS_MAP_WRITE because it's supposed
2280 * to update all raid stripes, but here we just want to correct
2281 * bad stripe, thus BTRFS_MAP_READ is abused to only get the bad
2282 * stripe's dev and sector.
2284 ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
2285 &map_length, &bbio, 0);
2287 btrfs_bio_counter_dec(fs_info);
2291 ASSERT(bbio->mirror_num == 1);
2293 ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
2294 &map_length, &bbio, mirror_num);
2296 btrfs_bio_counter_dec(fs_info);
2300 BUG_ON(mirror_num != bbio->mirror_num);
2303 sector = bbio->stripes[bbio->mirror_num - 1].physical >> 9;
2304 bio->bi_iter.bi_sector = sector;
2305 dev = bbio->stripes[bbio->mirror_num - 1].dev;
2306 btrfs_put_bbio(bbio);
2307 if (!dev || !dev->bdev ||
2308 !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
2309 btrfs_bio_counter_dec(fs_info);
2313 bio_set_dev(bio, dev->bdev);
2314 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
2315 bio_add_page(bio, page, length, pg_offset);
2317 if (btrfsic_submit_bio_wait(bio)) {
2318 /* try to remap that extent elsewhere? */
2319 btrfs_bio_counter_dec(fs_info);
2321 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2325 btrfs_info_rl_in_rcu(fs_info,
2326 "read error corrected: ino %llu off %llu (dev %s sector %llu)",
2328 rcu_str_deref(dev->name), sector);
2329 btrfs_bio_counter_dec(fs_info);
2334 int btrfs_repair_eb_io_failure(const struct extent_buffer *eb, int mirror_num)
2336 struct btrfs_fs_info *fs_info = eb->fs_info;
2337 u64 start = eb->start;
2338 int i, num_pages = num_extent_pages(eb);
2341 if (sb_rdonly(fs_info->sb))
2344 for (i = 0; i < num_pages; i++) {
2345 struct page *p = eb->pages[i];
2347 ret = repair_io_failure(fs_info, 0, start, PAGE_SIZE, start, p,
2348 start - page_offset(p), mirror_num);
2358 * each time an IO finishes, we do a fast check in the IO failure tree
2359 * to see if we need to process or clean up an io_failure_record
2361 int clean_io_failure(struct btrfs_fs_info *fs_info,
2362 struct extent_io_tree *failure_tree,
2363 struct extent_io_tree *io_tree, u64 start,
2364 struct page *page, u64 ino, unsigned int pg_offset)
2367 struct io_failure_record *failrec;
2368 struct extent_state *state;
2373 ret = count_range_bits(failure_tree, &private, (u64)-1, 1,
2378 failrec = get_state_failrec(failure_tree, start);
2379 if (IS_ERR(failrec))
2382 BUG_ON(!failrec->this_mirror);
2384 if (failrec->in_validation) {
2385 /* there was no real error, just free the record */
2386 btrfs_debug(fs_info,
2387 "clean_io_failure: freeing dummy error at %llu",
2391 if (sb_rdonly(fs_info->sb))
2394 spin_lock(&io_tree->lock);
2395 state = find_first_extent_bit_state(io_tree,
2398 spin_unlock(&io_tree->lock);
2400 if (state && state->start <= failrec->start &&
2401 state->end >= failrec->start + failrec->len - 1) {
2402 num_copies = btrfs_num_copies(fs_info, failrec->logical,
2404 if (num_copies > 1) {
2405 repair_io_failure(fs_info, ino, start, failrec->len,
2406 failrec->logical, page, pg_offset,
2407 failrec->failed_mirror);
2412 free_io_failure(failure_tree, io_tree, failrec);
2418 * Can be called when
2419 * - hold extent lock
2420 * - under ordered extent
2421 * - the inode is freeing
2423 void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start, u64 end)
2425 struct extent_io_tree *failure_tree = &inode->io_failure_tree;
2426 struct io_failure_record *failrec;
2427 struct extent_state *state, *next;
2429 if (RB_EMPTY_ROOT(&failure_tree->state))
2432 spin_lock(&failure_tree->lock);
2433 state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
2435 if (state->start > end)
2438 ASSERT(state->end <= end);
2440 next = next_state(state);
2442 failrec = state->failrec;
2443 free_extent_state(state);
2448 spin_unlock(&failure_tree->lock);
2451 static struct io_failure_record *btrfs_get_io_failure_record(struct inode *inode,
2454 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2455 struct io_failure_record *failrec;
2456 struct extent_map *em;
2457 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2458 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2459 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2463 failrec = get_state_failrec(failure_tree, start);
2464 if (!IS_ERR(failrec)) {
2465 btrfs_debug(fs_info,
2466 "Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d",
2467 failrec->logical, failrec->start, failrec->len,
2468 failrec->in_validation);
2470 * when data can be on disk more than twice, add to failrec here
2471 * (e.g. with a list for failed_mirror) to make
2472 * clean_io_failure() clean all those errors at once.
2478 failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
2480 return ERR_PTR(-ENOMEM);
2482 failrec->start = start;
2483 failrec->len = end - start + 1;
2484 failrec->this_mirror = 0;
2485 failrec->bio_flags = 0;
2486 failrec->in_validation = 0;
2488 read_lock(&em_tree->lock);
2489 em = lookup_extent_mapping(em_tree, start, failrec->len);
2491 read_unlock(&em_tree->lock);
2493 return ERR_PTR(-EIO);
2496 if (em->start > start || em->start + em->len <= start) {
2497 free_extent_map(em);
2500 read_unlock(&em_tree->lock);
2503 return ERR_PTR(-EIO);
2506 logical = start - em->start;
2507 logical = em->block_start + logical;
2508 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2509 logical = em->block_start;
2510 failrec->bio_flags = EXTENT_BIO_COMPRESSED;
2511 extent_set_compress_type(&failrec->bio_flags, em->compress_type);
2514 btrfs_debug(fs_info,
2515 "Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu",
2516 logical, start, failrec->len);
2518 failrec->logical = logical;
2519 free_extent_map(em);
2521 /* Set the bits in the private failure tree */
2522 ret = set_extent_bits(failure_tree, start, end,
2523 EXTENT_LOCKED | EXTENT_DIRTY);
2525 ret = set_state_failrec(failure_tree, start, failrec);
2526 /* Set the bits in the inode's tree */
2527 ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED);
2528 } else if (ret < 0) {
2530 return ERR_PTR(ret);
2536 static bool btrfs_check_repairable(struct inode *inode, bool needs_validation,
2537 struct io_failure_record *failrec,
2540 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2543 num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
2544 if (num_copies == 1) {
2546 * we only have a single copy of the data, so don't bother with
2547 * all the retry and error correction code that follows. no
2548 * matter what the error is, it is very likely to persist.
2550 btrfs_debug(fs_info,
2551 "Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
2552 num_copies, failrec->this_mirror, failed_mirror);
2557 * there are two premises:
2558 * a) deliver good data to the caller
2559 * b) correct the bad sectors on disk
2561 if (needs_validation) {
2563 * to fulfill b), we need to know the exact failing sectors, as
2564 * we don't want to rewrite any more than the failed ones. thus,
2565 * we need separate read requests for the failed bio
2567 * if the following BUG_ON triggers, our validation request got
2568 * merged. we need separate requests for our algorithm to work.
2570 BUG_ON(failrec->in_validation);
2571 failrec->in_validation = 1;
2572 failrec->this_mirror = failed_mirror;
2575 * we're ready to fulfill a) and b) alongside. get a good copy
2576 * of the failed sector and if we succeed, we have setup
2577 * everything for repair_io_failure to do the rest for us.
2579 if (failrec->in_validation) {
2580 BUG_ON(failrec->this_mirror != failed_mirror);
2581 failrec->in_validation = 0;
2582 failrec->this_mirror = 0;
2584 failrec->failed_mirror = failed_mirror;
2585 failrec->this_mirror++;
2586 if (failrec->this_mirror == failed_mirror)
2587 failrec->this_mirror++;
2590 if (failrec->this_mirror > num_copies) {
2591 btrfs_debug(fs_info,
2592 "Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
2593 num_copies, failrec->this_mirror, failed_mirror);
2600 static bool btrfs_io_needs_validation(struct inode *inode, struct bio *bio)
2603 const u32 blocksize = inode->i_sb->s_blocksize;
2606 * If bi_status is BLK_STS_OK, then this was a checksum error, not an
2607 * I/O error. In this case, we already know exactly which sector was
2608 * bad, so we don't need to validate.
2610 if (bio->bi_status == BLK_STS_OK)
2614 * We need to validate each sector individually if the failed I/O was
2615 * for multiple sectors.
2617 * There are a few possible bios that can end up here:
2618 * 1. A buffered read bio, which is not cloned.
2619 * 2. A direct I/O read bio, which is cloned.
2620 * 3. A (buffered or direct) repair bio, which is not cloned.
2622 * For cloned bios (case 2), we can get the size from
2623 * btrfs_io_bio->iter; for non-cloned bios (cases 1 and 3), we can get
2624 * it from the bvecs.
2626 if (bio_flagged(bio, BIO_CLONED)) {
2627 if (btrfs_io_bio(bio)->iter.bi_size > blocksize)
2630 struct bio_vec *bvec;
2633 bio_for_each_bvec_all(bvec, bio, i) {
2634 len += bvec->bv_len;
2635 if (len > blocksize)
2642 blk_status_t btrfs_submit_read_repair(struct inode *inode,
2643 struct bio *failed_bio, u32 bio_offset,
2644 struct page *page, unsigned int pgoff,
2645 u64 start, u64 end, int failed_mirror,
2646 submit_bio_hook_t *submit_bio_hook)
2648 struct io_failure_record *failrec;
2649 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2650 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2651 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2652 struct btrfs_io_bio *failed_io_bio = btrfs_io_bio(failed_bio);
2653 const int icsum = bio_offset >> fs_info->sectorsize_bits;
2654 bool need_validation;
2655 struct bio *repair_bio;
2656 struct btrfs_io_bio *repair_io_bio;
2657 blk_status_t status;
2659 btrfs_debug(fs_info,
2660 "repair read error: read error at %llu", start);
2662 BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
2664 failrec = btrfs_get_io_failure_record(inode, start, end);
2665 if (IS_ERR(failrec))
2666 return errno_to_blk_status(PTR_ERR(failrec));
2668 need_validation = btrfs_io_needs_validation(inode, failed_bio);
2670 if (!btrfs_check_repairable(inode, need_validation, failrec,
2672 free_io_failure(failure_tree, tree, failrec);
2673 return BLK_STS_IOERR;
2676 repair_bio = btrfs_io_bio_alloc(1);
2677 repair_io_bio = btrfs_io_bio(repair_bio);
2678 repair_bio->bi_opf = REQ_OP_READ;
2679 if (need_validation)
2680 repair_bio->bi_opf |= REQ_FAILFAST_DEV;
2681 repair_bio->bi_end_io = failed_bio->bi_end_io;
2682 repair_bio->bi_iter.bi_sector = failrec->logical >> 9;
2683 repair_bio->bi_private = failed_bio->bi_private;
2685 if (failed_io_bio->csum) {
2686 const u32 csum_size = fs_info->csum_size;
2688 repair_io_bio->csum = repair_io_bio->csum_inline;
2689 memcpy(repair_io_bio->csum,
2690 failed_io_bio->csum + csum_size * icsum, csum_size);
2693 bio_add_page(repair_bio, page, failrec->len, pgoff);
2694 repair_io_bio->logical = failrec->start;
2695 repair_io_bio->iter = repair_bio->bi_iter;
2697 btrfs_debug(btrfs_sb(inode->i_sb),
2698 "repair read error: submitting new read to mirror %d, in_validation=%d",
2699 failrec->this_mirror, failrec->in_validation);
2701 status = submit_bio_hook(inode, repair_bio, failrec->this_mirror,
2702 failrec->bio_flags);
2704 free_io_failure(failure_tree, tree, failrec);
2705 bio_put(repair_bio);
2710 /* lots and lots of room for performance fixes in the end_bio funcs */
2712 void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
2714 int uptodate = (err == 0);
2717 btrfs_writepage_endio_finish_ordered(page, start, end, uptodate);
2720 ClearPageUptodate(page);
2722 ret = err < 0 ? err : -EIO;
2723 mapping_set_error(page->mapping, ret);
2728 * after a writepage IO is done, we need to:
2729 * clear the uptodate bits on error
2730 * clear the writeback bits in the extent tree for this IO
2731 * end_page_writeback if the page has no more pending IO
2733 * Scheduling is not allowed, so the extent state tree is expected
2734 * to have one and only one object corresponding to this IO.
2736 static void end_bio_extent_writepage(struct bio *bio)
2738 int error = blk_status_to_errno(bio->bi_status);
2739 struct bio_vec *bvec;
2742 struct bvec_iter_all iter_all;
2743 bool first_bvec = true;
2745 ASSERT(!bio_flagged(bio, BIO_CLONED));
2746 bio_for_each_segment_all(bvec, bio, iter_all) {
2747 struct page *page = bvec->bv_page;
2748 struct inode *inode = page->mapping->host;
2749 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2751 /* We always issue full-page reads, but if some block
2752 * in a page fails to read, blk_update_request() will
2753 * advance bv_offset and adjust bv_len to compensate.
2754 * Print a warning for nonzero offsets, and an error
2755 * if they don't add up to a full page. */
2756 if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2757 if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2759 "partial page write in btrfs with offset %u and length %u",
2760 bvec->bv_offset, bvec->bv_len);
2763 "incomplete page write in btrfs with offset %u and length %u",
2764 bvec->bv_offset, bvec->bv_len);
2767 start = page_offset(page);
2768 end = start + bvec->bv_offset + bvec->bv_len - 1;
2771 btrfs_record_physical_zoned(inode, start, bio);
2775 end_extent_writepage(page, error, start, end);
2776 end_page_writeback(page);
2783 * Record previously processed extent range
2785 * For endio_readpage_release_extent() to handle a full extent range, reducing
2786 * the extent io operations.
2788 struct processed_extent {
2789 struct btrfs_inode *inode;
2790 /* Start of the range in @inode */
2792 /* End of the range in @inode */
2798 * Try to release processed extent range
2800 * May not release the extent range right now if the current range is
2801 * contiguous to processed extent.
2803 * Will release processed extent when any of @inode, @uptodate, the range is
2804 * no longer contiguous to the processed range.
2806 * Passing @inode == NULL will force processed extent to be released.
2808 static void endio_readpage_release_extent(struct processed_extent *processed,
2809 struct btrfs_inode *inode, u64 start, u64 end,
2812 struct extent_state *cached = NULL;
2813 struct extent_io_tree *tree;
2815 /* The first extent, initialize @processed */
2816 if (!processed->inode)
2820 * Contiguous to processed extent, just uptodate the end.
2822 * Several things to notice:
2824 * - bio can be merged as long as on-disk bytenr is contiguous
2825 * This means we can have page belonging to other inodes, thus need to
2826 * check if the inode still matches.
2827 * - bvec can contain range beyond current page for multi-page bvec
2828 * Thus we need to do processed->end + 1 >= start check
2830 if (processed->inode == inode && processed->uptodate == uptodate &&
2831 processed->end + 1 >= start && end >= processed->end) {
2832 processed->end = end;
2836 tree = &processed->inode->io_tree;
2838 * Now we don't have range contiguous to the processed range, release
2839 * the processed range now.
2841 if (processed->uptodate && tree->track_uptodate)
2842 set_extent_uptodate(tree, processed->start, processed->end,
2843 &cached, GFP_ATOMIC);
2844 unlock_extent_cached_atomic(tree, processed->start, processed->end,
2848 /* Update processed to current range */
2849 processed->inode = inode;
2850 processed->start = start;
2851 processed->end = end;
2852 processed->uptodate = uptodate;
2855 static void begin_page_read(struct btrfs_fs_info *fs_info, struct page *page)
2857 ASSERT(PageLocked(page));
2858 if (fs_info->sectorsize == PAGE_SIZE)
2861 ASSERT(PagePrivate(page));
2862 btrfs_subpage_start_reader(fs_info, page, page_offset(page), PAGE_SIZE);
2865 static void end_page_read(struct page *page, bool uptodate, u64 start, u32 len)
2867 struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
2869 ASSERT(page_offset(page) <= start &&
2870 start + len <= page_offset(page) + PAGE_SIZE);
2873 btrfs_page_set_uptodate(fs_info, page, start, len);
2875 btrfs_page_clear_uptodate(fs_info, page, start, len);
2876 btrfs_page_set_error(fs_info, page, start, len);
2879 if (fs_info->sectorsize == PAGE_SIZE)
2881 else if (is_data_inode(page->mapping->host))
2883 * For subpage data, unlock the page if we're the last reader.
2884 * For subpage metadata, page lock is not utilized for read.
2886 btrfs_subpage_end_reader(fs_info, page, start, len);
2890 * Find extent buffer for a givne bytenr.
2892 * This is for end_bio_extent_readpage(), thus we can't do any unsafe locking
2895 static struct extent_buffer *find_extent_buffer_readpage(
2896 struct btrfs_fs_info *fs_info, struct page *page, u64 bytenr)
2898 struct extent_buffer *eb;
2901 * For regular sectorsize, we can use page->private to grab extent
2904 if (fs_info->sectorsize == PAGE_SIZE) {
2905 ASSERT(PagePrivate(page) && page->private);
2906 return (struct extent_buffer *)page->private;
2909 /* For subpage case, we need to lookup buffer radix tree */
2911 eb = radix_tree_lookup(&fs_info->buffer_radix,
2912 bytenr >> fs_info->sectorsize_bits);
2919 * after a readpage IO is done, we need to:
2920 * clear the uptodate bits on error
2921 * set the uptodate bits if things worked
2922 * set the page up to date if all extents in the tree are uptodate
2923 * clear the lock bit in the extent tree
2924 * unlock the page if there are no other extents locked for it
2926 * Scheduling is not allowed, so the extent state tree is expected
2927 * to have one and only one object corresponding to this IO.
2929 static void end_bio_extent_readpage(struct bio *bio)
2931 struct bio_vec *bvec;
2932 int uptodate = !bio->bi_status;
2933 struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2934 struct extent_io_tree *tree, *failure_tree;
2935 struct processed_extent processed = { 0 };
2937 * The offset to the beginning of a bio, since one bio can never be
2938 * larger than UINT_MAX, u32 here is enough.
2943 struct bvec_iter_all iter_all;
2945 ASSERT(!bio_flagged(bio, BIO_CLONED));
2946 bio_for_each_segment_all(bvec, bio, iter_all) {
2947 struct page *page = bvec->bv_page;
2948 struct inode *inode = page->mapping->host;
2949 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2950 const u32 sectorsize = fs_info->sectorsize;
2955 btrfs_debug(fs_info,
2956 "end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
2957 bio->bi_iter.bi_sector, bio->bi_status,
2958 io_bio->mirror_num);
2959 tree = &BTRFS_I(inode)->io_tree;
2960 failure_tree = &BTRFS_I(inode)->io_failure_tree;
2963 * We always issue full-sector reads, but if some block in a
2964 * page fails to read, blk_update_request() will advance
2965 * bv_offset and adjust bv_len to compensate. Print a warning
2966 * for unaligned offsets, and an error if they don't add up to
2969 if (!IS_ALIGNED(bvec->bv_offset, sectorsize))
2971 "partial page read in btrfs with offset %u and length %u",
2972 bvec->bv_offset, bvec->bv_len);
2973 else if (!IS_ALIGNED(bvec->bv_offset + bvec->bv_len,
2976 "incomplete page read with offset %u and length %u",
2977 bvec->bv_offset, bvec->bv_len);
2979 start = page_offset(page) + bvec->bv_offset;
2980 end = start + bvec->bv_len - 1;
2983 mirror = io_bio->mirror_num;
2984 if (likely(uptodate)) {
2985 if (is_data_inode(inode))
2986 ret = btrfs_verify_data_csum(io_bio,
2987 bio_offset, page, start, end);
2989 ret = btrfs_validate_metadata_buffer(io_bio,
2990 page, start, end, mirror);
2994 clean_io_failure(BTRFS_I(inode)->root->fs_info,
2995 failure_tree, tree, start,
2997 btrfs_ino(BTRFS_I(inode)), 0);
3000 if (likely(uptodate))
3003 if (is_data_inode(inode)) {
3006 * The generic bio_readpage_error handles errors the
3007 * following way: If possible, new read requests are
3008 * created and submitted and will end up in
3009 * end_bio_extent_readpage as well (if we're lucky,
3010 * not in the !uptodate case). In that case it returns
3011 * 0 and we just go on with the next page in our bio.
3012 * If it can't handle the error it will return -EIO and
3013 * we remain responsible for that page.
3015 if (!btrfs_submit_read_repair(inode, bio, bio_offset,
3017 start - page_offset(page),
3019 btrfs_submit_data_bio)) {
3020 uptodate = !bio->bi_status;
3021 ASSERT(bio_offset + len > bio_offset);
3026 struct extent_buffer *eb;
3028 eb = find_extent_buffer_readpage(fs_info, page, start);
3029 set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
3030 eb->read_mirror = mirror;
3031 atomic_dec(&eb->io_pages);
3032 if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD,
3034 btree_readahead_hook(eb, -EIO);
3037 if (likely(uptodate)) {
3038 loff_t i_size = i_size_read(inode);
3039 pgoff_t end_index = i_size >> PAGE_SHIFT;
3042 * Zero out the remaining part if this range straddles
3045 * Here we should only zero the range inside the bvec,
3046 * not touch anything else.
3048 * NOTE: i_size is exclusive while end is inclusive.
3050 if (page->index == end_index && i_size <= end) {
3051 u32 zero_start = max(offset_in_page(i_size),
3052 offset_in_page(start));
3054 zero_user_segment(page, zero_start,
3055 offset_in_page(end) + 1);
3058 ASSERT(bio_offset + len > bio_offset);
3061 /* Update page status and unlock */
3062 end_page_read(page, uptodate, start, len);
3063 endio_readpage_release_extent(&processed, BTRFS_I(inode),
3064 start, end, uptodate);
3066 /* Release the last extent */
3067 endio_readpage_release_extent(&processed, NULL, 0, 0, false);
3068 btrfs_io_bio_free_csum(io_bio);
3073 * Initialize the members up to but not including 'bio'. Use after allocating a
3074 * new bio by bio_alloc_bioset as it does not initialize the bytes outside of
3075 * 'bio' because use of __GFP_ZERO is not supported.
3077 static inline void btrfs_io_bio_init(struct btrfs_io_bio *btrfs_bio)
3079 memset(btrfs_bio, 0, offsetof(struct btrfs_io_bio, bio));
3083 * The following helpers allocate a bio. As it's backed by a bioset, it'll
3084 * never fail. We're returning a bio right now but you can call btrfs_io_bio
3085 * for the appropriate container_of magic
3087 struct bio *btrfs_bio_alloc(u64 first_byte)
3091 bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_VECS, &btrfs_bioset);
3092 bio->bi_iter.bi_sector = first_byte >> 9;
3093 btrfs_io_bio_init(btrfs_io_bio(bio));
3097 struct bio *btrfs_bio_clone(struct bio *bio)
3099 struct btrfs_io_bio *btrfs_bio;
3102 /* Bio allocation backed by a bioset does not fail */
3103 new = bio_clone_fast(bio, GFP_NOFS, &btrfs_bioset);
3104 btrfs_bio = btrfs_io_bio(new);
3105 btrfs_io_bio_init(btrfs_bio);
3106 btrfs_bio->iter = bio->bi_iter;
3110 struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs)
3114 /* Bio allocation backed by a bioset does not fail */
3115 bio = bio_alloc_bioset(GFP_NOFS, nr_iovecs, &btrfs_bioset);
3116 btrfs_io_bio_init(btrfs_io_bio(bio));
3120 struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size)
3123 struct btrfs_io_bio *btrfs_bio;
3125 /* this will never fail when it's backed by a bioset */
3126 bio = bio_clone_fast(orig, GFP_NOFS, &btrfs_bioset);
3129 btrfs_bio = btrfs_io_bio(bio);
3130 btrfs_io_bio_init(btrfs_bio);
3132 bio_trim(bio, offset >> 9, size >> 9);
3133 btrfs_bio->iter = bio->bi_iter;
3138 * Attempt to add a page to bio
3140 * @bio: destination bio
3141 * @page: page to add to the bio
3142 * @disk_bytenr: offset of the new bio or to check whether we are adding
3143 * a contiguous page to the previous one
3144 * @pg_offset: starting offset in the page
3145 * @size: portion of page that we want to write
3146 * @prev_bio_flags: flags of previous bio to see if we can merge the current one
3147 * @bio_flags: flags of the current bio to see if we can merge them
3148 * @return: true if page was added, false otherwise
3150 * Attempt to add a page to bio considering stripe alignment etc.
3152 * Return true if successfully page added. Otherwise, return false.
3154 static bool btrfs_bio_add_page(struct bio *bio, struct page *page,
3155 u64 disk_bytenr, unsigned int size,
3156 unsigned int pg_offset,
3157 unsigned long prev_bio_flags,
3158 unsigned long bio_flags)
3160 const sector_t sector = disk_bytenr >> SECTOR_SHIFT;
3164 if (prev_bio_flags != bio_flags)
3167 if (prev_bio_flags & EXTENT_BIO_COMPRESSED)
3168 contig = bio->bi_iter.bi_sector == sector;
3170 contig = bio_end_sector(bio) == sector;
3174 if (btrfs_bio_fits_in_stripe(page, size, bio, bio_flags))
3177 if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
3178 struct page *first_page = bio_first_bvec_all(bio)->bv_page;
3180 if (!btrfs_bio_fits_in_ordered_extent(first_page, bio, size))
3182 ret = bio_add_zone_append_page(bio, page, size, pg_offset);
3184 ret = bio_add_page(bio, page, size, pg_offset);
3191 * @opf: bio REQ_OP_* and REQ_* flags as one value
3192 * @wbc: optional writeback control for io accounting
3193 * @page: page to add to the bio
3194 * @disk_bytenr: logical bytenr where the write will be
3195 * @size: portion of page that we want to write to
3196 * @pg_offset: offset of the new bio or to check whether we are adding
3197 * a contiguous page to the previous one
3198 * @bio_ret: must be valid pointer, newly allocated bio will be stored there
3199 * @end_io_func: end_io callback for new bio
3200 * @mirror_num: desired mirror to read/write
3201 * @prev_bio_flags: flags of previous bio to see if we can merge the current one
3202 * @bio_flags: flags of the current bio to see if we can merge them
3204 static int submit_extent_page(unsigned int opf,
3205 struct writeback_control *wbc,
3206 struct page *page, u64 disk_bytenr,
3207 size_t size, unsigned long pg_offset,
3208 struct bio **bio_ret,
3209 bio_end_io_t end_io_func,
3211 unsigned long prev_bio_flags,
3212 unsigned long bio_flags,
3213 bool force_bio_submit)
3217 size_t io_size = min_t(size_t, size, PAGE_SIZE);
3218 struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
3219 struct extent_io_tree *tree = &inode->io_tree;
3220 struct btrfs_fs_info *fs_info = inode->root->fs_info;
3226 if (force_bio_submit ||
3227 !btrfs_bio_add_page(bio, page, disk_bytenr, io_size,
3228 pg_offset, prev_bio_flags, bio_flags)) {
3229 ret = submit_one_bio(bio, mirror_num, prev_bio_flags);
3237 wbc_account_cgroup_owner(wbc, page, io_size);
3242 bio = btrfs_bio_alloc(disk_bytenr);
3243 bio_add_page(bio, page, io_size, pg_offset);
3244 bio->bi_end_io = end_io_func;
3245 bio->bi_private = tree;
3246 bio->bi_write_hint = page->mapping->host->i_write_hint;
3249 struct block_device *bdev;
3251 bdev = fs_info->fs_devices->latest_bdev;
3252 bio_set_dev(bio, bdev);
3253 wbc_init_bio(wbc, bio);
3254 wbc_account_cgroup_owner(wbc, page, io_size);
3256 if (btrfs_is_zoned(fs_info) && bio_op(bio) == REQ_OP_ZONE_APPEND) {
3257 struct extent_map *em;
3258 struct map_lookup *map;
3260 em = btrfs_get_chunk_map(fs_info, disk_bytenr, io_size);
3264 map = em->map_lookup;
3265 /* We only support single profile for now */
3266 ASSERT(map->num_stripes == 1);
3267 btrfs_io_bio(bio)->device = map->stripes[0].dev;
3269 free_extent_map(em);
3277 static int attach_extent_buffer_page(struct extent_buffer *eb,
3279 struct btrfs_subpage *prealloc)
3281 struct btrfs_fs_info *fs_info = eb->fs_info;
3285 * If the page is mapped to btree inode, we should hold the private
3286 * lock to prevent race.
3287 * For cloned or dummy extent buffers, their pages are not mapped and
3288 * will not race with any other ebs.
3291 lockdep_assert_held(&page->mapping->private_lock);
3293 if (fs_info->sectorsize == PAGE_SIZE) {
3294 if (!PagePrivate(page))
3295 attach_page_private(page, eb);
3297 WARN_ON(page->private != (unsigned long)eb);
3301 /* Already mapped, just free prealloc */
3302 if (PagePrivate(page)) {
3303 btrfs_free_subpage(prealloc);
3308 /* Has preallocated memory for subpage */
3309 attach_page_private(page, prealloc);
3311 /* Do new allocation to attach subpage */
3312 ret = btrfs_attach_subpage(fs_info, page,
3313 BTRFS_SUBPAGE_METADATA);
3317 int set_page_extent_mapped(struct page *page)
3319 struct btrfs_fs_info *fs_info;
3321 ASSERT(page->mapping);
3323 if (PagePrivate(page))
3326 fs_info = btrfs_sb(page->mapping->host->i_sb);
3328 if (fs_info->sectorsize < PAGE_SIZE)
3329 return btrfs_attach_subpage(fs_info, page, BTRFS_SUBPAGE_DATA);
3331 attach_page_private(page, (void *)EXTENT_PAGE_PRIVATE);
3335 void clear_page_extent_mapped(struct page *page)
3337 struct btrfs_fs_info *fs_info;
3339 ASSERT(page->mapping);
3341 if (!PagePrivate(page))
3344 fs_info = btrfs_sb(page->mapping->host->i_sb);
3345 if (fs_info->sectorsize < PAGE_SIZE)
3346 return btrfs_detach_subpage(fs_info, page);
3348 detach_page_private(page);
3351 static struct extent_map *
3352 __get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
3353 u64 start, u64 len, struct extent_map **em_cached)
3355 struct extent_map *em;
3357 if (em_cached && *em_cached) {
3359 if (extent_map_in_tree(em) && start >= em->start &&
3360 start < extent_map_end(em)) {
3361 refcount_inc(&em->refs);
3365 free_extent_map(em);
3369 em = btrfs_get_extent(BTRFS_I(inode), page, pg_offset, start, len);
3370 if (em_cached && !IS_ERR_OR_NULL(em)) {
3372 refcount_inc(&em->refs);
3378 * basic readpage implementation. Locked extent state structs are inserted
3379 * into the tree that are removed when the IO is done (by the end_io
3381 * XXX JDM: This needs looking at to ensure proper page locking
3382 * return 0 on success, otherwise return error
3384 int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
3385 struct bio **bio, unsigned long *bio_flags,
3386 unsigned int read_flags, u64 *prev_em_start)
3388 struct inode *inode = page->mapping->host;
3389 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3390 u64 start = page_offset(page);
3391 const u64 end = start + PAGE_SIZE - 1;
3394 u64 last_byte = i_size_read(inode);
3397 struct extent_map *em;
3400 size_t pg_offset = 0;
3402 size_t blocksize = inode->i_sb->s_blocksize;
3403 unsigned long this_bio_flag = 0;
3404 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
3406 ret = set_page_extent_mapped(page);
3408 unlock_extent(tree, start, end);
3409 btrfs_page_set_error(fs_info, page, start, PAGE_SIZE);
3414 if (!PageUptodate(page)) {
3415 if (cleancache_get_page(page) == 0) {
3416 BUG_ON(blocksize != PAGE_SIZE);
3417 unlock_extent(tree, start, end);
3423 if (page->index == last_byte >> PAGE_SHIFT) {
3425 size_t zero_offset = offset_in_page(last_byte);
3428 iosize = PAGE_SIZE - zero_offset;
3429 userpage = kmap_atomic(page);
3430 memset(userpage + zero_offset, 0, iosize);
3431 flush_dcache_page(page);
3432 kunmap_atomic(userpage);
3435 begin_page_read(fs_info, page);
3436 while (cur <= end) {
3437 bool force_bio_submit = false;
3440 if (cur >= last_byte) {
3442 struct extent_state *cached = NULL;
3444 iosize = PAGE_SIZE - pg_offset;
3445 userpage = kmap_atomic(page);
3446 memset(userpage + pg_offset, 0, iosize);
3447 flush_dcache_page(page);
3448 kunmap_atomic(userpage);
3449 set_extent_uptodate(tree, cur, cur + iosize - 1,
3451 unlock_extent_cached(tree, cur,
3452 cur + iosize - 1, &cached);
3453 end_page_read(page, true, cur, iosize);
3456 em = __get_extent_map(inode, page, pg_offset, cur,
3457 end - cur + 1, em_cached);
3458 if (IS_ERR_OR_NULL(em)) {
3459 unlock_extent(tree, cur, end);
3460 end_page_read(page, false, cur, end + 1 - cur);
3463 extent_offset = cur - em->start;
3464 BUG_ON(extent_map_end(em) <= cur);
3467 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
3468 this_bio_flag |= EXTENT_BIO_COMPRESSED;
3469 extent_set_compress_type(&this_bio_flag,
3473 iosize = min(extent_map_end(em) - cur, end - cur + 1);
3474 cur_end = min(extent_map_end(em) - 1, end);
3475 iosize = ALIGN(iosize, blocksize);
3476 if (this_bio_flag & EXTENT_BIO_COMPRESSED)
3477 disk_bytenr = em->block_start;
3479 disk_bytenr = em->block_start + extent_offset;
3480 block_start = em->block_start;
3481 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
3482 block_start = EXTENT_MAP_HOLE;
3485 * If we have a file range that points to a compressed extent
3486 * and it's followed by a consecutive file range that points
3487 * to the same compressed extent (possibly with a different
3488 * offset and/or length, so it either points to the whole extent
3489 * or only part of it), we must make sure we do not submit a
3490 * single bio to populate the pages for the 2 ranges because
3491 * this makes the compressed extent read zero out the pages
3492 * belonging to the 2nd range. Imagine the following scenario:
3495 * [0 - 8K] [8K - 24K]
3498 * points to extent X, points to extent X,
3499 * offset 4K, length of 8K offset 0, length 16K
3501 * [extent X, compressed length = 4K uncompressed length = 16K]
3503 * If the bio to read the compressed extent covers both ranges,
3504 * it will decompress extent X into the pages belonging to the
3505 * first range and then it will stop, zeroing out the remaining
3506 * pages that belong to the other range that points to extent X.
3507 * So here we make sure we submit 2 bios, one for the first
3508 * range and another one for the third range. Both will target
3509 * the same physical extent from disk, but we can't currently
3510 * make the compressed bio endio callback populate the pages
3511 * for both ranges because each compressed bio is tightly
3512 * coupled with a single extent map, and each range can have
3513 * an extent map with a different offset value relative to the
3514 * uncompressed data of our extent and different lengths. This
3515 * is a corner case so we prioritize correctness over
3516 * non-optimal behavior (submitting 2 bios for the same extent).
3518 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
3519 prev_em_start && *prev_em_start != (u64)-1 &&
3520 *prev_em_start != em->start)
3521 force_bio_submit = true;
3524 *prev_em_start = em->start;
3526 free_extent_map(em);
3529 /* we've found a hole, just zero and go on */
3530 if (block_start == EXTENT_MAP_HOLE) {
3532 struct extent_state *cached = NULL;
3534 userpage = kmap_atomic(page);
3535 memset(userpage + pg_offset, 0, iosize);
3536 flush_dcache_page(page);
3537 kunmap_atomic(userpage);
3539 set_extent_uptodate(tree, cur, cur + iosize - 1,
3541 unlock_extent_cached(tree, cur,
3542 cur + iosize - 1, &cached);
3543 end_page_read(page, true, cur, iosize);
3545 pg_offset += iosize;
3548 /* the get_extent function already copied into the page */
3549 if (test_range_bit(tree, cur, cur_end,
3550 EXTENT_UPTODATE, 1, NULL)) {
3551 check_page_uptodate(tree, page);
3552 unlock_extent(tree, cur, cur + iosize - 1);
3553 end_page_read(page, true, cur, iosize);
3555 pg_offset += iosize;
3558 /* we have an inline extent but it didn't get marked up
3559 * to date. Error out
3561 if (block_start == EXTENT_MAP_INLINE) {
3562 unlock_extent(tree, cur, cur + iosize - 1);
3563 end_page_read(page, false, cur, iosize);
3565 pg_offset += iosize;
3569 ret = submit_extent_page(REQ_OP_READ | read_flags, NULL,
3570 page, disk_bytenr, iosize,
3572 end_bio_extent_readpage, 0,
3578 *bio_flags = this_bio_flag;
3580 unlock_extent(tree, cur, cur + iosize - 1);
3581 end_page_read(page, false, cur, iosize);
3585 pg_offset += iosize;
3591 static inline void contiguous_readpages(struct page *pages[], int nr_pages,
3593 struct extent_map **em_cached,
3595 unsigned long *bio_flags,
3598 struct btrfs_inode *inode = BTRFS_I(pages[0]->mapping->host);
3601 btrfs_lock_and_flush_ordered_range(inode, start, end, NULL);
3603 for (index = 0; index < nr_pages; index++) {
3604 btrfs_do_readpage(pages[index], em_cached, bio, bio_flags,
3605 REQ_RAHEAD, prev_em_start);
3606 put_page(pages[index]);
3610 static void update_nr_written(struct writeback_control *wbc,
3611 unsigned long nr_written)
3613 wbc->nr_to_write -= nr_written;
3617 * helper for __extent_writepage, doing all of the delayed allocation setup.
3619 * This returns 1 if btrfs_run_delalloc_range function did all the work required
3620 * to write the page (copy into inline extent). In this case the IO has
3621 * been started and the page is already unlocked.
3623 * This returns 0 if all went well (page still locked)
3624 * This returns < 0 if there were errors (page still locked)
3626 static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
3627 struct page *page, struct writeback_control *wbc,
3628 u64 delalloc_start, unsigned long *nr_written)
3630 u64 page_end = delalloc_start + PAGE_SIZE - 1;
3632 u64 delalloc_to_write = 0;
3633 u64 delalloc_end = 0;
3635 int page_started = 0;
3638 while (delalloc_end < page_end) {
3639 found = find_lock_delalloc_range(&inode->vfs_inode, page,
3643 delalloc_start = delalloc_end + 1;
3646 ret = btrfs_run_delalloc_range(inode, page, delalloc_start,
3647 delalloc_end, &page_started, nr_written, wbc);
3651 * btrfs_run_delalloc_range should return < 0 for error
3652 * but just in case, we use > 0 here meaning the IO is
3653 * started, so we don't want to return > 0 unless
3654 * things are going well.
3656 return ret < 0 ? ret : -EIO;
3659 * delalloc_end is already one less than the total length, so
3660 * we don't subtract one from PAGE_SIZE
3662 delalloc_to_write += (delalloc_end - delalloc_start +
3663 PAGE_SIZE) >> PAGE_SHIFT;
3664 delalloc_start = delalloc_end + 1;
3666 if (wbc->nr_to_write < delalloc_to_write) {
3669 if (delalloc_to_write < thresh * 2)
3670 thresh = delalloc_to_write;
3671 wbc->nr_to_write = min_t(u64, delalloc_to_write,
3675 /* did the fill delalloc function already unlock and start
3680 * we've unlocked the page, so we can't update
3681 * the mapping's writeback index, just update
3684 wbc->nr_to_write -= *nr_written;
3692 * helper for __extent_writepage. This calls the writepage start hooks,
3693 * and does the loop to map the page into extents and bios.
3695 * We return 1 if the IO is started and the page is unlocked,
3696 * 0 if all went well (page still locked)
3697 * < 0 if there were errors (page still locked)
3699 static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
3701 struct writeback_control *wbc,
3702 struct extent_page_data *epd,
3704 unsigned long nr_written,
3707 struct btrfs_fs_info *fs_info = inode->root->fs_info;
3708 struct extent_io_tree *tree = &inode->io_tree;
3709 u64 start = page_offset(page);
3710 u64 end = start + PAGE_SIZE - 1;
3714 struct extent_map *em;
3717 u32 opf = REQ_OP_WRITE;
3718 const unsigned int write_flags = wbc_to_write_flags(wbc);
3721 ret = btrfs_writepage_cow_fixup(page, start, end);
3723 /* Fixup worker will requeue */
3724 redirty_page_for_writepage(wbc, page);
3725 update_nr_written(wbc, nr_written);
3731 * we don't want to touch the inode after unlocking the page,
3732 * so we update the mapping writeback index now
3734 update_nr_written(wbc, nr_written + 1);
3736 while (cur <= end) {
3741 if (cur >= i_size) {
3742 btrfs_writepage_endio_finish_ordered(page, cur, end, 1);
3745 em = btrfs_get_extent(inode, NULL, 0, cur, end - cur + 1);
3746 if (IS_ERR_OR_NULL(em)) {
3748 ret = PTR_ERR_OR_ZERO(em);
3752 extent_offset = cur - em->start;
3753 em_end = extent_map_end(em);
3754 ASSERT(cur <= em_end);
3756 ASSERT(IS_ALIGNED(em->start, fs_info->sectorsize));
3757 ASSERT(IS_ALIGNED(em->len, fs_info->sectorsize));
3758 block_start = em->block_start;
3759 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3760 disk_bytenr = em->block_start + extent_offset;
3762 /* Note that em_end from extent_map_end() is exclusive */
3763 iosize = min(em_end, end + 1) - cur;
3765 if (btrfs_use_zone_append(inode, em))
3766 opf = REQ_OP_ZONE_APPEND;
3768 free_extent_map(em);
3772 * compressed and inline extents are written through other
3775 if (compressed || block_start == EXTENT_MAP_HOLE ||
3776 block_start == EXTENT_MAP_INLINE) {
3780 btrfs_writepage_endio_finish_ordered(page, cur,
3781 cur + iosize - 1, 1);
3786 btrfs_set_range_writeback(tree, cur, cur + iosize - 1);
3787 if (!PageWriteback(page)) {
3788 btrfs_err(inode->root->fs_info,
3789 "page %lu not writeback, cur %llu end %llu",
3790 page->index, cur, end);
3793 ret = submit_extent_page(opf | write_flags, wbc, page,
3794 disk_bytenr, iosize,
3795 cur - page_offset(page), &epd->bio,
3796 end_bio_extent_writepage,
3800 if (PageWriteback(page))
3801 end_page_writeback(page);
3812 * the writepage semantics are similar to regular writepage. extent
3813 * records are inserted to lock ranges in the tree, and as dirty areas
3814 * are found, they are marked writeback. Then the lock bits are removed
3815 * and the end_io handler clears the writeback ranges
3817 * Return 0 if everything goes well.
3818 * Return <0 for error.
3820 static int __extent_writepage(struct page *page, struct writeback_control *wbc,
3821 struct extent_page_data *epd)
3823 struct inode *inode = page->mapping->host;
3824 u64 start = page_offset(page);
3825 u64 page_end = start + PAGE_SIZE - 1;
3829 loff_t i_size = i_size_read(inode);
3830 unsigned long end_index = i_size >> PAGE_SHIFT;
3831 unsigned long nr_written = 0;
3833 trace___extent_writepage(page, inode, wbc);
3835 WARN_ON(!PageLocked(page));
3837 ClearPageError(page);
3839 pg_offset = offset_in_page(i_size);
3840 if (page->index > end_index ||
3841 (page->index == end_index && !pg_offset)) {
3842 page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
3847 if (page->index == end_index) {
3850 userpage = kmap_atomic(page);
3851 memset(userpage + pg_offset, 0,
3852 PAGE_SIZE - pg_offset);
3853 kunmap_atomic(userpage);
3854 flush_dcache_page(page);
3857 ret = set_page_extent_mapped(page);
3863 if (!epd->extent_locked) {
3864 ret = writepage_delalloc(BTRFS_I(inode), page, wbc, start,
3872 ret = __extent_writepage_io(BTRFS_I(inode), page, wbc, epd, i_size,
3879 /* make sure the mapping tag for page dirty gets cleared */
3880 set_page_writeback(page);
3881 end_page_writeback(page);
3883 if (PageError(page)) {
3884 ret = ret < 0 ? ret : -EIO;
3885 end_extent_writepage(page, ret, start, page_end);
3892 void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3894 wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
3895 TASK_UNINTERRUPTIBLE);
3898 static void end_extent_buffer_writeback(struct extent_buffer *eb)
3900 clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3901 smp_mb__after_atomic();
3902 wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
3906 * Lock extent buffer status and pages for writeback.
3908 * May try to flush write bio if we can't get the lock.
3910 * Return 0 if the extent buffer doesn't need to be submitted.
3911 * (E.g. the extent buffer is not dirty)
3912 * Return >0 is the extent buffer is submitted to bio.
3913 * Return <0 if something went wrong, no page is locked.
3915 static noinline_for_stack int lock_extent_buffer_for_io(struct extent_buffer *eb,
3916 struct extent_page_data *epd)
3918 struct btrfs_fs_info *fs_info = eb->fs_info;
3919 int i, num_pages, failed_page_nr;
3923 if (!btrfs_try_tree_write_lock(eb)) {
3924 ret = flush_write_bio(epd);
3928 btrfs_tree_lock(eb);
3931 if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
3932 btrfs_tree_unlock(eb);
3936 ret = flush_write_bio(epd);
3942 wait_on_extent_buffer_writeback(eb);
3943 btrfs_tree_lock(eb);
3944 if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
3946 btrfs_tree_unlock(eb);
3951 * We need to do this to prevent races in people who check if the eb is
3952 * under IO since we can end up having no IO bits set for a short period
3955 spin_lock(&eb->refs_lock);
3956 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3957 set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3958 spin_unlock(&eb->refs_lock);
3959 btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3960 percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
3962 fs_info->dirty_metadata_batch);
3965 spin_unlock(&eb->refs_lock);
3968 btrfs_tree_unlock(eb);
3973 num_pages = num_extent_pages(eb);
3974 for (i = 0; i < num_pages; i++) {
3975 struct page *p = eb->pages[i];
3977 if (!trylock_page(p)) {
3981 err = flush_write_bio(epd);
3995 /* Unlock already locked pages */
3996 for (i = 0; i < failed_page_nr; i++)
3997 unlock_page(eb->pages[i]);
3999 * Clear EXTENT_BUFFER_WRITEBACK and wake up anyone waiting on it.
4000 * Also set back EXTENT_BUFFER_DIRTY so future attempts to this eb can
4001 * be made and undo everything done before.
4003 btrfs_tree_lock(eb);
4004 spin_lock(&eb->refs_lock);
4005 set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
4006 end_extent_buffer_writeback(eb);
4007 spin_unlock(&eb->refs_lock);
4008 percpu_counter_add_batch(&fs_info->dirty_metadata_bytes, eb->len,
4009 fs_info->dirty_metadata_batch);
4010 btrfs_clear_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
4011 btrfs_tree_unlock(eb);
4015 static void set_btree_ioerr(struct page *page, struct extent_buffer *eb)
4017 struct btrfs_fs_info *fs_info = eb->fs_info;
4019 btrfs_page_set_error(fs_info, page, eb->start, eb->len);
4020 if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
4024 * If we error out, we should add back the dirty_metadata_bytes
4025 * to make it consistent.
4027 percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
4028 eb->len, fs_info->dirty_metadata_batch);
4031 * If writeback for a btree extent that doesn't belong to a log tree
4032 * failed, increment the counter transaction->eb_write_errors.
4033 * We do this because while the transaction is running and before it's
4034 * committing (when we call filemap_fdata[write|wait]_range against
4035 * the btree inode), we might have
4036 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
4037 * returns an error or an error happens during writeback, when we're
4038 * committing the transaction we wouldn't know about it, since the pages
4039 * can be no longer dirty nor marked anymore for writeback (if a
4040 * subsequent modification to the extent buffer didn't happen before the
4041 * transaction commit), which makes filemap_fdata[write|wait]_range not
4042 * able to find the pages tagged with SetPageError at transaction
4043 * commit time. So if this happens we must abort the transaction,
4044 * otherwise we commit a super block with btree roots that point to
4045 * btree nodes/leafs whose content on disk is invalid - either garbage
4046 * or the content of some node/leaf from a past generation that got
4047 * cowed or deleted and is no longer valid.
4049 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
4050 * not be enough - we need to distinguish between log tree extents vs
4051 * non-log tree extents, and the next filemap_fdatawait_range() call
4052 * will catch and clear such errors in the mapping - and that call might
4053 * be from a log sync and not from a transaction commit. Also, checking
4054 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
4055 * not done and would not be reliable - the eb might have been released
4056 * from memory and reading it back again means that flag would not be
4057 * set (since it's a runtime flag, not persisted on disk).
4059 * Using the flags below in the btree inode also makes us achieve the
4060 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
4061 * writeback for all dirty pages and before filemap_fdatawait_range()
4062 * is called, the writeback for all dirty pages had already finished
4063 * with errors - because we were not using AS_EIO/AS_ENOSPC,
4064 * filemap_fdatawait_range() would return success, as it could not know
4065 * that writeback errors happened (the pages were no longer tagged for
4068 switch (eb->log_index) {
4070 set_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags);
4073 set_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
4076 set_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
4079 BUG(); /* unexpected, logic error */
4084 * The endio specific version which won't touch any unsafe spinlock in endio
4087 static struct extent_buffer *find_extent_buffer_nolock(
4088 struct btrfs_fs_info *fs_info, u64 start)
4090 struct extent_buffer *eb;
4093 eb = radix_tree_lookup(&fs_info->buffer_radix,
4094 start >> fs_info->sectorsize_bits);
4095 if (eb && atomic_inc_not_zero(&eb->refs)) {
4104 * The endio function for subpage extent buffer write.
4106 * Unlike end_bio_extent_buffer_writepage(), we only call end_page_writeback()
4107 * after all extent buffers in the page has finished their writeback.
4109 static void end_bio_subpage_eb_writepage(struct btrfs_fs_info *fs_info,
4112 struct bio_vec *bvec;
4113 struct bvec_iter_all iter_all;
4115 ASSERT(!bio_flagged(bio, BIO_CLONED));
4116 bio_for_each_segment_all(bvec, bio, iter_all) {
4117 struct page *page = bvec->bv_page;
4118 u64 bvec_start = page_offset(page) + bvec->bv_offset;
4119 u64 bvec_end = bvec_start + bvec->bv_len - 1;
4120 u64 cur_bytenr = bvec_start;
4122 ASSERT(IS_ALIGNED(bvec->bv_len, fs_info->nodesize));
4124 /* Iterate through all extent buffers in the range */
4125 while (cur_bytenr <= bvec_end) {
4126 struct extent_buffer *eb;
4130 * Here we can't use find_extent_buffer(), as it may
4131 * try to lock eb->refs_lock, which is not safe in endio
4134 eb = find_extent_buffer_nolock(fs_info, cur_bytenr);
4137 cur_bytenr = eb->start + eb->len;
4139 ASSERT(test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags));
4140 done = atomic_dec_and_test(&eb->io_pages);
4143 if (bio->bi_status ||
4144 test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
4145 ClearPageUptodate(page);
4146 set_btree_ioerr(page, eb);
4149 btrfs_subpage_clear_writeback(fs_info, page, eb->start,
4151 end_extent_buffer_writeback(eb);
4153 * free_extent_buffer() will grab spinlock which is not
4154 * safe in endio context. Thus here we manually dec
4157 atomic_dec(&eb->refs);
4163 static void end_bio_extent_buffer_writepage(struct bio *bio)
4165 struct btrfs_fs_info *fs_info;
4166 struct bio_vec *bvec;
4167 struct extent_buffer *eb;
4169 struct bvec_iter_all iter_all;
4171 fs_info = btrfs_sb(bio_first_page_all(bio)->mapping->host->i_sb);
4172 if (fs_info->sectorsize < PAGE_SIZE)
4173 return end_bio_subpage_eb_writepage(fs_info, bio);
4175 ASSERT(!bio_flagged(bio, BIO_CLONED));
4176 bio_for_each_segment_all(bvec, bio, iter_all) {
4177 struct page *page = bvec->bv_page;
4179 eb = (struct extent_buffer *)page->private;
4181 done = atomic_dec_and_test(&eb->io_pages);
4183 if (bio->bi_status ||
4184 test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
4185 ClearPageUptodate(page);
4186 set_btree_ioerr(page, eb);
4189 end_page_writeback(page);
4194 end_extent_buffer_writeback(eb);
4200 static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
4201 struct writeback_control *wbc,
4202 struct extent_page_data *epd)
4204 u64 disk_bytenr = eb->start;
4207 unsigned long start, end;
4208 unsigned int write_flags = wbc_to_write_flags(wbc) | REQ_META;
4211 clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
4212 num_pages = num_extent_pages(eb);
4213 atomic_set(&eb->io_pages, num_pages);
4215 /* set btree blocks beyond nritems with 0 to avoid stale content. */
4216 nritems = btrfs_header_nritems(eb);
4217 if (btrfs_header_level(eb) > 0) {
4218 end = btrfs_node_key_ptr_offset(nritems);
4220 memzero_extent_buffer(eb, end, eb->len - end);
4224 * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
4226 start = btrfs_item_nr_offset(nritems);
4227 end = BTRFS_LEAF_DATA_OFFSET + leaf_data_end(eb);
4228 memzero_extent_buffer(eb, start, end - start);
4231 for (i = 0; i < num_pages; i++) {
4232 struct page *p = eb->pages[i];
4234 clear_page_dirty_for_io(p);
4235 set_page_writeback(p);
4236 ret = submit_extent_page(REQ_OP_WRITE | write_flags, wbc,
4237 p, disk_bytenr, PAGE_SIZE, 0,
4239 end_bio_extent_buffer_writepage,
4242 set_btree_ioerr(p, eb);
4243 if (PageWriteback(p))
4244 end_page_writeback(p);
4245 if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
4246 end_extent_buffer_writeback(eb);
4250 disk_bytenr += PAGE_SIZE;
4251 update_nr_written(wbc, 1);
4255 if (unlikely(ret)) {
4256 for (; i < num_pages; i++) {
4257 struct page *p = eb->pages[i];
4258 clear_page_dirty_for_io(p);
4267 * Submit all page(s) of one extent buffer.
4269 * @page: the page of one extent buffer
4270 * @eb_context: to determine if we need to submit this page, if current page
4271 * belongs to this eb, we don't need to submit
4273 * The caller should pass each page in their bytenr order, and here we use
4274 * @eb_context to determine if we have submitted pages of one extent buffer.
4276 * If we have, we just skip until we hit a new page that doesn't belong to
4277 * current @eb_context.
4279 * If not, we submit all the page(s) of the extent buffer.
4281 * Return >0 if we have submitted the extent buffer successfully.
4282 * Return 0 if we don't need to submit the page, as it's already submitted by
4284 * Return <0 for fatal error.
4286 static int submit_eb_page(struct page *page, struct writeback_control *wbc,
4287 struct extent_page_data *epd,
4288 struct extent_buffer **eb_context)
4290 struct address_space *mapping = page->mapping;
4291 struct btrfs_block_group *cache = NULL;
4292 struct extent_buffer *eb;
4295 if (!PagePrivate(page))
4298 spin_lock(&mapping->private_lock);
4299 if (!PagePrivate(page)) {
4300 spin_unlock(&mapping->private_lock);
4304 eb = (struct extent_buffer *)page->private;
4307 * Shouldn't happen and normally this would be a BUG_ON but no point
4308 * crashing the machine for something we can survive anyway.
4311 spin_unlock(&mapping->private_lock);
4315 if (eb == *eb_context) {
4316 spin_unlock(&mapping->private_lock);
4319 ret = atomic_inc_not_zero(&eb->refs);
4320 spin_unlock(&mapping->private_lock);
4324 if (!btrfs_check_meta_write_pointer(eb->fs_info, eb, &cache)) {
4326 * If for_sync, this hole will be filled with
4327 * trasnsaction commit.
4329 if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
4333 free_extent_buffer(eb);
4339 ret = lock_extent_buffer_for_io(eb, epd);
4341 btrfs_revert_meta_write_pointer(cache, eb);
4343 btrfs_put_block_group(cache);
4344 free_extent_buffer(eb);
4348 btrfs_put_block_group(cache);
4349 ret = write_one_eb(eb, wbc, epd);
4350 free_extent_buffer(eb);
4356 int btree_write_cache_pages(struct address_space *mapping,
4357 struct writeback_control *wbc)
4359 struct extent_buffer *eb_context = NULL;
4360 struct extent_page_data epd = {
4363 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4365 struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
4368 int nr_to_write_done = 0;
4369 struct pagevec pvec;
4372 pgoff_t end; /* Inclusive */
4376 pagevec_init(&pvec);
4377 if (wbc->range_cyclic) {
4378 index = mapping->writeback_index; /* Start from prev offset */
4381 * Start from the beginning does not need to cycle over the
4382 * range, mark it as scanned.
4384 scanned = (index == 0);
4386 index = wbc->range_start >> PAGE_SHIFT;
4387 end = wbc->range_end >> PAGE_SHIFT;
4390 if (wbc->sync_mode == WB_SYNC_ALL)
4391 tag = PAGECACHE_TAG_TOWRITE;
4393 tag = PAGECACHE_TAG_DIRTY;
4394 btrfs_zoned_meta_io_lock(fs_info);
4396 if (wbc->sync_mode == WB_SYNC_ALL)
4397 tag_pages_for_writeback(mapping, index, end);
4398 while (!done && !nr_to_write_done && (index <= end) &&
4399 (nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
4403 for (i = 0; i < nr_pages; i++) {
4404 struct page *page = pvec.pages[i];
4406 ret = submit_eb_page(page, wbc, &epd, &eb_context);
4415 * the filesystem may choose to bump up nr_to_write.
4416 * We have to make sure to honor the new nr_to_write
4419 nr_to_write_done = wbc->nr_to_write <= 0;
4421 pagevec_release(&pvec);
4424 if (!scanned && !done) {
4426 * We hit the last page and there is more work to be done: wrap
4427 * back to the start of the file
4434 end_write_bio(&epd, ret);
4438 * If something went wrong, don't allow any metadata write bio to be
4441 * This would prevent use-after-free if we had dirty pages not
4442 * cleaned up, which can still happen by fuzzed images.
4445 * Allowing existing tree block to be allocated for other trees.
4447 * - Log tree operations
4448 * Exiting tree blocks get allocated to log tree, bumps its
4449 * generation, then get cleaned in tree re-balance.
4450 * Such tree block will not be written back, since it's clean,
4451 * thus no WRITTEN flag set.
4452 * And after log writes back, this tree block is not traced by
4453 * any dirty extent_io_tree.
4455 * - Offending tree block gets re-dirtied from its original owner
4456 * Since it has bumped generation, no WRITTEN flag, it can be
4457 * reused without COWing. This tree block will not be traced
4458 * by btrfs_transaction::dirty_pages.
4460 * Now such dirty tree block will not be cleaned by any dirty
4461 * extent io tree. Thus we don't want to submit such wild eb
4462 * if the fs already has error.
4464 if (!test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
4465 ret = flush_write_bio(&epd);
4468 end_write_bio(&epd, ret);
4471 btrfs_zoned_meta_io_unlock(fs_info);
4476 * Walk the list of dirty pages of the given address space and write all of them.
4478 * @mapping: address space structure to write
4479 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
4480 * @epd: holds context for the write, namely the bio
4482 * If a page is already under I/O, write_cache_pages() skips it, even
4483 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
4484 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
4485 * and msync() need to guarantee that all the data which was dirty at the time
4486 * the call was made get new I/O started against them. If wbc->sync_mode is
4487 * WB_SYNC_ALL then we were called for data integrity and we must wait for
4488 * existing IO to complete.
4490 static int extent_write_cache_pages(struct address_space *mapping,
4491 struct writeback_control *wbc,
4492 struct extent_page_data *epd)
4494 struct inode *inode = mapping->host;
4497 int nr_to_write_done = 0;
4498 struct pagevec pvec;
4501 pgoff_t end; /* Inclusive */
4503 int range_whole = 0;
4508 * We have to hold onto the inode so that ordered extents can do their
4509 * work when the IO finishes. The alternative to this is failing to add
4510 * an ordered extent if the igrab() fails there and that is a huge pain
4511 * to deal with, so instead just hold onto the inode throughout the
4512 * writepages operation. If it fails here we are freeing up the inode
4513 * anyway and we'd rather not waste our time writing out stuff that is
4514 * going to be truncated anyway.
4519 pagevec_init(&pvec);
4520 if (wbc->range_cyclic) {
4521 index = mapping->writeback_index; /* Start from prev offset */
4524 * Start from the beginning does not need to cycle over the
4525 * range, mark it as scanned.
4527 scanned = (index == 0);
4529 index = wbc->range_start >> PAGE_SHIFT;
4530 end = wbc->range_end >> PAGE_SHIFT;
4531 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
4537 * We do the tagged writepage as long as the snapshot flush bit is set
4538 * and we are the first one who do the filemap_flush() on this inode.
4540 * The nr_to_write == LONG_MAX is needed to make sure other flushers do
4541 * not race in and drop the bit.
4543 if (range_whole && wbc->nr_to_write == LONG_MAX &&
4544 test_and_clear_bit(BTRFS_INODE_SNAPSHOT_FLUSH,
4545 &BTRFS_I(inode)->runtime_flags))
4546 wbc->tagged_writepages = 1;
4548 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
4549 tag = PAGECACHE_TAG_TOWRITE;
4551 tag = PAGECACHE_TAG_DIRTY;
4553 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
4554 tag_pages_for_writeback(mapping, index, end);
4556 while (!done && !nr_to_write_done && (index <= end) &&
4557 (nr_pages = pagevec_lookup_range_tag(&pvec, mapping,
4558 &index, end, tag))) {
4561 for (i = 0; i < nr_pages; i++) {
4562 struct page *page = pvec.pages[i];
4564 done_index = page->index + 1;
4566 * At this point we hold neither the i_pages lock nor
4567 * the page lock: the page may be truncated or
4568 * invalidated (changing page->mapping to NULL),
4569 * or even swizzled back from swapper_space to
4570 * tmpfs file mapping
4572 if (!trylock_page(page)) {
4573 ret = flush_write_bio(epd);
4578 if (unlikely(page->mapping != mapping)) {
4583 if (wbc->sync_mode != WB_SYNC_NONE) {
4584 if (PageWriteback(page)) {
4585 ret = flush_write_bio(epd);
4588 wait_on_page_writeback(page);
4591 if (PageWriteback(page) ||
4592 !clear_page_dirty_for_io(page)) {
4597 ret = __extent_writepage(page, wbc, epd);
4604 * the filesystem may choose to bump up nr_to_write.
4605 * We have to make sure to honor the new nr_to_write
4608 nr_to_write_done = wbc->nr_to_write <= 0;
4610 pagevec_release(&pvec);
4613 if (!scanned && !done) {
4615 * We hit the last page and there is more work to be done: wrap
4616 * back to the start of the file
4622 * If we're looping we could run into a page that is locked by a
4623 * writer and that writer could be waiting on writeback for a
4624 * page in our current bio, and thus deadlock, so flush the
4627 ret = flush_write_bio(epd);
4632 if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
4633 mapping->writeback_index = done_index;
4635 btrfs_add_delayed_iput(inode);
4639 int extent_write_full_page(struct page *page, struct writeback_control *wbc)
4642 struct extent_page_data epd = {
4645 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4648 ret = __extent_writepage(page, wbc, &epd);
4651 end_write_bio(&epd, ret);
4655 ret = flush_write_bio(&epd);
4660 int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
4664 struct address_space *mapping = inode->i_mapping;
4666 unsigned long nr_pages = (end - start + PAGE_SIZE) >>
4669 struct extent_page_data epd = {
4672 .sync_io = mode == WB_SYNC_ALL,
4674 struct writeback_control wbc_writepages = {
4676 .nr_to_write = nr_pages * 2,
4677 .range_start = start,
4678 .range_end = end + 1,
4679 /* We're called from an async helper function */
4680 .punt_to_cgroup = 1,
4681 .no_cgroup_owner = 1,
4684 wbc_attach_fdatawrite_inode(&wbc_writepages, inode);
4685 while (start <= end) {
4686 page = find_get_page(mapping, start >> PAGE_SHIFT);
4687 if (clear_page_dirty_for_io(page))
4688 ret = __extent_writepage(page, &wbc_writepages, &epd);
4690 btrfs_writepage_endio_finish_ordered(page, start,
4691 start + PAGE_SIZE - 1, 1);
4700 ret = flush_write_bio(&epd);
4702 end_write_bio(&epd, ret);
4704 wbc_detach_inode(&wbc_writepages);
4708 int extent_writepages(struct address_space *mapping,
4709 struct writeback_control *wbc)
4712 struct extent_page_data epd = {
4715 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4718 ret = extent_write_cache_pages(mapping, wbc, &epd);
4721 end_write_bio(&epd, ret);
4724 ret = flush_write_bio(&epd);
4728 void extent_readahead(struct readahead_control *rac)
4730 struct bio *bio = NULL;
4731 unsigned long bio_flags = 0;
4732 struct page *pagepool[16];
4733 struct extent_map *em_cached = NULL;
4734 u64 prev_em_start = (u64)-1;
4737 while ((nr = readahead_page_batch(rac, pagepool))) {
4738 u64 contig_start = readahead_pos(rac);
4739 u64 contig_end = contig_start + readahead_batch_length(rac) - 1;
4741 contiguous_readpages(pagepool, nr, contig_start, contig_end,
4742 &em_cached, &bio, &bio_flags, &prev_em_start);
4746 free_extent_map(em_cached);
4749 if (submit_one_bio(bio, 0, bio_flags))
4755 * basic invalidatepage code, this waits on any locked or writeback
4756 * ranges corresponding to the page, and then deletes any extent state
4757 * records from the tree
4759 int extent_invalidatepage(struct extent_io_tree *tree,
4760 struct page *page, unsigned long offset)
4762 struct extent_state *cached_state = NULL;
4763 u64 start = page_offset(page);
4764 u64 end = start + PAGE_SIZE - 1;
4765 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
4767 /* This function is only called for the btree inode */
4768 ASSERT(tree->owner == IO_TREE_BTREE_INODE_IO);
4770 start += ALIGN(offset, blocksize);
4774 lock_extent_bits(tree, start, end, &cached_state);
4775 wait_on_page_writeback(page);
4778 * Currently for btree io tree, only EXTENT_LOCKED is utilized,
4779 * so here we only need to unlock the extent range to free any
4780 * existing extent state.
4782 unlock_extent_cached(tree, start, end, &cached_state);
4787 * a helper for releasepage, this tests for areas of the page that
4788 * are locked or under IO and drops the related state bits if it is safe
4791 static int try_release_extent_state(struct extent_io_tree *tree,
4792 struct page *page, gfp_t mask)
4794 u64 start = page_offset(page);
4795 u64 end = start + PAGE_SIZE - 1;
4798 if (test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL)) {
4802 * At this point we can safely clear everything except the
4803 * locked bit, the nodatasum bit and the delalloc new bit.
4804 * The delalloc new bit will be cleared by ordered extent
4807 ret = __clear_extent_bit(tree, start, end,
4808 ~(EXTENT_LOCKED | EXTENT_NODATASUM | EXTENT_DELALLOC_NEW),
4809 0, 0, NULL, mask, NULL);
4811 /* if clear_extent_bit failed for enomem reasons,
4812 * we can't allow the release to continue.
4823 * a helper for releasepage. As long as there are no locked extents
4824 * in the range corresponding to the page, both state records and extent
4825 * map records are removed
4827 int try_release_extent_mapping(struct page *page, gfp_t mask)
4829 struct extent_map *em;
4830 u64 start = page_offset(page);
4831 u64 end = start + PAGE_SIZE - 1;
4832 struct btrfs_inode *btrfs_inode = BTRFS_I(page->mapping->host);
4833 struct extent_io_tree *tree = &btrfs_inode->io_tree;
4834 struct extent_map_tree *map = &btrfs_inode->extent_tree;
4836 if (gfpflags_allow_blocking(mask) &&
4837 page->mapping->host->i_size > SZ_16M) {
4839 while (start <= end) {
4840 struct btrfs_fs_info *fs_info;
4843 len = end - start + 1;
4844 write_lock(&map->lock);
4845 em = lookup_extent_mapping(map, start, len);
4847 write_unlock(&map->lock);
4850 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
4851 em->start != start) {
4852 write_unlock(&map->lock);
4853 free_extent_map(em);
4856 if (test_range_bit(tree, em->start,
4857 extent_map_end(em) - 1,
4858 EXTENT_LOCKED, 0, NULL))
4861 * If it's not in the list of modified extents, used
4862 * by a fast fsync, we can remove it. If it's being
4863 * logged we can safely remove it since fsync took an
4864 * extra reference on the em.
4866 if (list_empty(&em->list) ||
4867 test_bit(EXTENT_FLAG_LOGGING, &em->flags))
4870 * If it's in the list of modified extents, remove it
4871 * only if its generation is older then the current one,
4872 * in which case we don't need it for a fast fsync.
4873 * Otherwise don't remove it, we could be racing with an
4874 * ongoing fast fsync that could miss the new extent.
4876 fs_info = btrfs_inode->root->fs_info;
4877 spin_lock(&fs_info->trans_lock);
4878 cur_gen = fs_info->generation;
4879 spin_unlock(&fs_info->trans_lock);
4880 if (em->generation >= cur_gen)
4884 * We only remove extent maps that are not in the list of
4885 * modified extents or that are in the list but with a
4886 * generation lower then the current generation, so there
4887 * is no need to set the full fsync flag on the inode (it
4888 * hurts the fsync performance for workloads with a data
4889 * size that exceeds or is close to the system's memory).
4891 remove_extent_mapping(map, em);
4892 /* once for the rb tree */
4893 free_extent_map(em);
4895 start = extent_map_end(em);
4896 write_unlock(&map->lock);
4899 free_extent_map(em);
4901 cond_resched(); /* Allow large-extent preemption. */
4904 return try_release_extent_state(tree, page, mask);
4908 * helper function for fiemap, which doesn't want to see any holes.
4909 * This maps until we find something past 'last'
4911 static struct extent_map *get_extent_skip_holes(struct btrfs_inode *inode,
4912 u64 offset, u64 last)
4914 u64 sectorsize = btrfs_inode_sectorsize(inode);
4915 struct extent_map *em;
4922 len = last - offset;
4925 len = ALIGN(len, sectorsize);
4926 em = btrfs_get_extent_fiemap(inode, offset, len);
4927 if (IS_ERR_OR_NULL(em))
4930 /* if this isn't a hole return it */
4931 if (em->block_start != EXTENT_MAP_HOLE)
4934 /* this is a hole, advance to the next extent */
4935 offset = extent_map_end(em);
4936 free_extent_map(em);
4944 * To cache previous fiemap extent
4946 * Will be used for merging fiemap extent
4948 struct fiemap_cache {
4957 * Helper to submit fiemap extent.
4959 * Will try to merge current fiemap extent specified by @offset, @phys,
4960 * @len and @flags with cached one.
4961 * And only when we fails to merge, cached one will be submitted as
4964 * Return value is the same as fiemap_fill_next_extent().
4966 static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
4967 struct fiemap_cache *cache,
4968 u64 offset, u64 phys, u64 len, u32 flags)
4976 * Sanity check, extent_fiemap() should have ensured that new
4977 * fiemap extent won't overlap with cached one.
4980 * NOTE: Physical address can overlap, due to compression
4982 if (cache->offset + cache->len > offset) {
4988 * Only merges fiemap extents if
4989 * 1) Their logical addresses are continuous
4991 * 2) Their physical addresses are continuous
4992 * So truly compressed (physical size smaller than logical size)
4993 * extents won't get merged with each other
4995 * 3) Share same flags except FIEMAP_EXTENT_LAST
4996 * So regular extent won't get merged with prealloc extent
4998 if (cache->offset + cache->len == offset &&
4999 cache->phys + cache->len == phys &&
5000 (cache->flags & ~FIEMAP_EXTENT_LAST) ==
5001 (flags & ~FIEMAP_EXTENT_LAST)) {
5003 cache->flags |= flags;
5004 goto try_submit_last;
5007 /* Not mergeable, need to submit cached one */
5008 ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
5009 cache->len, cache->flags);
5010 cache->cached = false;
5014 cache->cached = true;
5015 cache->offset = offset;
5018 cache->flags = flags;
5020 if (cache->flags & FIEMAP_EXTENT_LAST) {
5021 ret = fiemap_fill_next_extent(fieinfo, cache->offset,
5022 cache->phys, cache->len, cache->flags);
5023 cache->cached = false;
5029 * Emit last fiemap cache
5031 * The last fiemap cache may still be cached in the following case:
5033 * |<- Fiemap range ->|
5034 * |<------------ First extent ----------->|
5036 * In this case, the first extent range will be cached but not emitted.
5037 * So we must emit it before ending extent_fiemap().
5039 static int emit_last_fiemap_cache(struct fiemap_extent_info *fieinfo,
5040 struct fiemap_cache *cache)
5047 ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
5048 cache->len, cache->flags);
5049 cache->cached = false;
5055 int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
5060 u64 max = start + len;
5064 u64 last_for_get_extent = 0;
5066 u64 isize = i_size_read(&inode->vfs_inode);
5067 struct btrfs_key found_key;
5068 struct extent_map *em = NULL;
5069 struct extent_state *cached_state = NULL;
5070 struct btrfs_path *path;
5071 struct btrfs_root *root = inode->root;
5072 struct fiemap_cache cache = { 0 };
5073 struct ulist *roots;
5074 struct ulist *tmp_ulist;
5083 path = btrfs_alloc_path();
5087 roots = ulist_alloc(GFP_KERNEL);
5088 tmp_ulist = ulist_alloc(GFP_KERNEL);
5089 if (!roots || !tmp_ulist) {
5091 goto out_free_ulist;
5094 start = round_down(start, btrfs_inode_sectorsize(inode));
5095 len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
5098 * lookup the last file extent. We're not using i_size here
5099 * because there might be preallocation past i_size
5101 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode), -1,
5104 goto out_free_ulist;
5112 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
5113 found_type = found_key.type;
5115 /* No extents, but there might be delalloc bits */
5116 if (found_key.objectid != btrfs_ino(inode) ||
5117 found_type != BTRFS_EXTENT_DATA_KEY) {
5118 /* have to trust i_size as the end */
5120 last_for_get_extent = isize;
5123 * remember the start of the last extent. There are a
5124 * bunch of different factors that go into the length of the
5125 * extent, so its much less complex to remember where it started
5127 last = found_key.offset;
5128 last_for_get_extent = last + 1;
5130 btrfs_release_path(path);
5133 * we might have some extents allocated but more delalloc past those
5134 * extents. so, we trust isize unless the start of the last extent is
5139 last_for_get_extent = isize;
5142 lock_extent_bits(&inode->io_tree, start, start + len - 1,
5145 em = get_extent_skip_holes(inode, start, last_for_get_extent);
5154 u64 offset_in_extent = 0;
5156 /* break if the extent we found is outside the range */
5157 if (em->start >= max || extent_map_end(em) < off)
5161 * get_extent may return an extent that starts before our
5162 * requested range. We have to make sure the ranges
5163 * we return to fiemap always move forward and don't
5164 * overlap, so adjust the offsets here
5166 em_start = max(em->start, off);
5169 * record the offset from the start of the extent
5170 * for adjusting the disk offset below. Only do this if the
5171 * extent isn't compressed since our in ram offset may be past
5172 * what we have actually allocated on disk.
5174 if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
5175 offset_in_extent = em_start - em->start;
5176 em_end = extent_map_end(em);
5177 em_len = em_end - em_start;
5179 if (em->block_start < EXTENT_MAP_LAST_BYTE)
5180 disko = em->block_start + offset_in_extent;
5185 * bump off for our next call to get_extent
5187 off = extent_map_end(em);
5191 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
5193 flags |= FIEMAP_EXTENT_LAST;
5194 } else if (em->block_start == EXTENT_MAP_INLINE) {
5195 flags |= (FIEMAP_EXTENT_DATA_INLINE |
5196 FIEMAP_EXTENT_NOT_ALIGNED);
5197 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
5198 flags |= (FIEMAP_EXTENT_DELALLOC |
5199 FIEMAP_EXTENT_UNKNOWN);
5200 } else if (fieinfo->fi_extents_max) {
5201 u64 bytenr = em->block_start -
5202 (em->start - em->orig_start);
5205 * As btrfs supports shared space, this information
5206 * can be exported to userspace tools via
5207 * flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0
5208 * then we're just getting a count and we can skip the
5211 ret = btrfs_check_shared(root, btrfs_ino(inode),
5212 bytenr, roots, tmp_ulist);
5216 flags |= FIEMAP_EXTENT_SHARED;
5219 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
5220 flags |= FIEMAP_EXTENT_ENCODED;
5221 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
5222 flags |= FIEMAP_EXTENT_UNWRITTEN;
5224 free_extent_map(em);
5226 if ((em_start >= last) || em_len == (u64)-1 ||
5227 (last == (u64)-1 && isize <= em_end)) {
5228 flags |= FIEMAP_EXTENT_LAST;
5232 /* now scan forward to see if this is really the last extent. */
5233 em = get_extent_skip_holes(inode, off, last_for_get_extent);
5239 flags |= FIEMAP_EXTENT_LAST;
5242 ret = emit_fiemap_extent(fieinfo, &cache, em_start, disko,
5252 ret = emit_last_fiemap_cache(fieinfo, &cache);
5253 free_extent_map(em);
5255 unlock_extent_cached(&inode->io_tree, start, start + len - 1,
5259 btrfs_free_path(path);
5261 ulist_free(tmp_ulist);
5265 static void __free_extent_buffer(struct extent_buffer *eb)
5267 kmem_cache_free(extent_buffer_cache, eb);
5270 int extent_buffer_under_io(const struct extent_buffer *eb)
5272 return (atomic_read(&eb->io_pages) ||
5273 test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
5274 test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
5277 static bool page_range_has_eb(struct btrfs_fs_info *fs_info, struct page *page)
5279 struct btrfs_subpage *subpage;
5281 lockdep_assert_held(&page->mapping->private_lock);
5283 if (PagePrivate(page)) {
5284 subpage = (struct btrfs_subpage *)page->private;
5285 if (atomic_read(&subpage->eb_refs))
5291 static void detach_extent_buffer_page(struct extent_buffer *eb, struct page *page)
5293 struct btrfs_fs_info *fs_info = eb->fs_info;
5294 const bool mapped = !test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
5297 * For mapped eb, we're going to change the page private, which should
5298 * be done under the private_lock.
5301 spin_lock(&page->mapping->private_lock);
5303 if (!PagePrivate(page)) {
5305 spin_unlock(&page->mapping->private_lock);
5309 if (fs_info->sectorsize == PAGE_SIZE) {
5311 * We do this since we'll remove the pages after we've
5312 * removed the eb from the radix tree, so we could race
5313 * and have this page now attached to the new eb. So
5314 * only clear page_private if it's still connected to
5317 if (PagePrivate(page) &&
5318 page->private == (unsigned long)eb) {
5319 BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
5320 BUG_ON(PageDirty(page));
5321 BUG_ON(PageWriteback(page));
5323 * We need to make sure we haven't be attached
5326 detach_page_private(page);
5329 spin_unlock(&page->mapping->private_lock);
5334 * For subpage, we can have dummy eb with page private. In this case,
5335 * we can directly detach the private as such page is only attached to
5336 * one dummy eb, no sharing.
5339 btrfs_detach_subpage(fs_info, page);
5343 btrfs_page_dec_eb_refs(fs_info, page);
5346 * We can only detach the page private if there are no other ebs in the
5349 if (!page_range_has_eb(fs_info, page))
5350 btrfs_detach_subpage(fs_info, page);
5352 spin_unlock(&page->mapping->private_lock);
5355 /* Release all pages attached to the extent buffer */
5356 static void btrfs_release_extent_buffer_pages(struct extent_buffer *eb)
5361 ASSERT(!extent_buffer_under_io(eb));
5363 num_pages = num_extent_pages(eb);
5364 for (i = 0; i < num_pages; i++) {
5365 struct page *page = eb->pages[i];
5370 detach_extent_buffer_page(eb, page);
5372 /* One for when we allocated the page */
5378 * Helper for releasing the extent buffer.
5380 static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
5382 btrfs_release_extent_buffer_pages(eb);
5383 btrfs_leak_debug_del(&eb->fs_info->eb_leak_lock, &eb->leak_list);
5384 __free_extent_buffer(eb);
5387 static struct extent_buffer *
5388 __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
5391 struct extent_buffer *eb = NULL;
5393 eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
5396 eb->fs_info = fs_info;
5398 init_rwsem(&eb->lock);
5400 btrfs_leak_debug_add(&fs_info->eb_leak_lock, &eb->leak_list,
5401 &fs_info->allocated_ebs);
5402 INIT_LIST_HEAD(&eb->release_list);
5404 spin_lock_init(&eb->refs_lock);
5405 atomic_set(&eb->refs, 1);
5406 atomic_set(&eb->io_pages, 0);
5408 ASSERT(len <= BTRFS_MAX_METADATA_BLOCKSIZE);
5413 struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src)
5417 struct extent_buffer *new;
5418 int num_pages = num_extent_pages(src);
5420 new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
5425 * Set UNMAPPED before calling btrfs_release_extent_buffer(), as
5426 * btrfs_release_extent_buffer() have different behavior for
5427 * UNMAPPED subpage extent buffer.
5429 set_bit(EXTENT_BUFFER_UNMAPPED, &new->bflags);
5431 for (i = 0; i < num_pages; i++) {
5434 p = alloc_page(GFP_NOFS);
5436 btrfs_release_extent_buffer(new);
5439 ret = attach_extent_buffer_page(new, p, NULL);
5442 btrfs_release_extent_buffer(new);
5445 WARN_ON(PageDirty(p));
5447 copy_page(page_address(p), page_address(src->pages[i]));
5449 set_extent_buffer_uptodate(new);
5454 struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
5455 u64 start, unsigned long len)
5457 struct extent_buffer *eb;
5461 eb = __alloc_extent_buffer(fs_info, start, len);
5465 num_pages = num_extent_pages(eb);
5466 for (i = 0; i < num_pages; i++) {
5469 eb->pages[i] = alloc_page(GFP_NOFS);
5472 ret = attach_extent_buffer_page(eb, eb->pages[i], NULL);
5476 set_extent_buffer_uptodate(eb);
5477 btrfs_set_header_nritems(eb, 0);
5478 set_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
5482 for (; i > 0; i--) {
5483 detach_extent_buffer_page(eb, eb->pages[i - 1]);
5484 __free_page(eb->pages[i - 1]);
5486 __free_extent_buffer(eb);
5490 struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
5493 return __alloc_dummy_extent_buffer(fs_info, start, fs_info->nodesize);
5496 static void check_buffer_tree_ref(struct extent_buffer *eb)
5500 * The TREE_REF bit is first set when the extent_buffer is added
5501 * to the radix tree. It is also reset, if unset, when a new reference
5502 * is created by find_extent_buffer.
5504 * It is only cleared in two cases: freeing the last non-tree
5505 * reference to the extent_buffer when its STALE bit is set or
5506 * calling releasepage when the tree reference is the only reference.
5508 * In both cases, care is taken to ensure that the extent_buffer's
5509 * pages are not under io. However, releasepage can be concurrently
5510 * called with creating new references, which is prone to race
5511 * conditions between the calls to check_buffer_tree_ref in those
5512 * codepaths and clearing TREE_REF in try_release_extent_buffer.
5514 * The actual lifetime of the extent_buffer in the radix tree is
5515 * adequately protected by the refcount, but the TREE_REF bit and
5516 * its corresponding reference are not. To protect against this
5517 * class of races, we call check_buffer_tree_ref from the codepaths
5518 * which trigger io after they set eb->io_pages. Note that once io is
5519 * initiated, TREE_REF can no longer be cleared, so that is the
5520 * moment at which any such race is best fixed.
5522 refs = atomic_read(&eb->refs);
5523 if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5526 spin_lock(&eb->refs_lock);
5527 if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5528 atomic_inc(&eb->refs);
5529 spin_unlock(&eb->refs_lock);
5532 static void mark_extent_buffer_accessed(struct extent_buffer *eb,
5533 struct page *accessed)
5537 check_buffer_tree_ref(eb);
5539 num_pages = num_extent_pages(eb);
5540 for (i = 0; i < num_pages; i++) {
5541 struct page *p = eb->pages[i];
5544 mark_page_accessed(p);
5548 struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
5551 struct extent_buffer *eb;
5553 eb = find_extent_buffer_nolock(fs_info, start);
5557 * Lock our eb's refs_lock to avoid races with free_extent_buffer().
5558 * When we get our eb it might be flagged with EXTENT_BUFFER_STALE and
5559 * another task running free_extent_buffer() might have seen that flag
5560 * set, eb->refs == 2, that the buffer isn't under IO (dirty and
5561 * writeback flags not set) and it's still in the tree (flag
5562 * EXTENT_BUFFER_TREE_REF set), therefore being in the process of
5563 * decrementing the extent buffer's reference count twice. So here we
5564 * could race and increment the eb's reference count, clear its stale
5565 * flag, mark it as dirty and drop our reference before the other task
5566 * finishes executing free_extent_buffer, which would later result in
5567 * an attempt to free an extent buffer that is dirty.
5569 if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
5570 spin_lock(&eb->refs_lock);
5571 spin_unlock(&eb->refs_lock);
5573 mark_extent_buffer_accessed(eb, NULL);
5577 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5578 struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
5581 struct extent_buffer *eb, *exists = NULL;
5584 eb = find_extent_buffer(fs_info, start);
5587 eb = alloc_dummy_extent_buffer(fs_info, start);
5589 return ERR_PTR(-ENOMEM);
5590 eb->fs_info = fs_info;
5592 ret = radix_tree_preload(GFP_NOFS);
5594 exists = ERR_PTR(ret);
5597 spin_lock(&fs_info->buffer_lock);
5598 ret = radix_tree_insert(&fs_info->buffer_radix,
5599 start >> fs_info->sectorsize_bits, eb);
5600 spin_unlock(&fs_info->buffer_lock);
5601 radix_tree_preload_end();
5602 if (ret == -EEXIST) {
5603 exists = find_extent_buffer(fs_info, start);
5609 check_buffer_tree_ref(eb);
5610 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
5614 btrfs_release_extent_buffer(eb);
5619 static struct extent_buffer *grab_extent_buffer(
5620 struct btrfs_fs_info *fs_info, struct page *page)
5622 struct extent_buffer *exists;
5625 * For subpage case, we completely rely on radix tree to ensure we
5626 * don't try to insert two ebs for the same bytenr. So here we always
5627 * return NULL and just continue.
5629 if (fs_info->sectorsize < PAGE_SIZE)
5632 /* Page not yet attached to an extent buffer */
5633 if (!PagePrivate(page))
5637 * We could have already allocated an eb for this page and attached one
5638 * so lets see if we can get a ref on the existing eb, and if we can we
5639 * know it's good and we can just return that one, else we know we can
5640 * just overwrite page->private.
5642 exists = (struct extent_buffer *)page->private;
5643 if (atomic_inc_not_zero(&exists->refs))
5646 WARN_ON(PageDirty(page));
5647 detach_page_private(page);
5651 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
5652 u64 start, u64 owner_root, int level)
5654 unsigned long len = fs_info->nodesize;
5657 unsigned long index = start >> PAGE_SHIFT;
5658 struct extent_buffer *eb;
5659 struct extent_buffer *exists = NULL;
5661 struct address_space *mapping = fs_info->btree_inode->i_mapping;
5665 if (!IS_ALIGNED(start, fs_info->sectorsize)) {
5666 btrfs_err(fs_info, "bad tree block start %llu", start);
5667 return ERR_PTR(-EINVAL);
5670 if (fs_info->sectorsize < PAGE_SIZE &&
5671 offset_in_page(start) + len > PAGE_SIZE) {
5673 "tree block crosses page boundary, start %llu nodesize %lu",
5675 return ERR_PTR(-EINVAL);
5678 eb = find_extent_buffer(fs_info, start);
5682 eb = __alloc_extent_buffer(fs_info, start, len);
5684 return ERR_PTR(-ENOMEM);
5685 btrfs_set_buffer_lockdep_class(owner_root, eb, level);
5687 num_pages = num_extent_pages(eb);
5688 for (i = 0; i < num_pages; i++, index++) {
5689 struct btrfs_subpage *prealloc = NULL;
5691 p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
5693 exists = ERR_PTR(-ENOMEM);
5698 * Preallocate page->private for subpage case, so that we won't
5699 * allocate memory with private_lock hold. The memory will be
5700 * freed by attach_extent_buffer_page() or freed manually if
5703 * Although we have ensured one subpage eb can only have one
5704 * page, but it may change in the future for 16K page size
5705 * support, so we still preallocate the memory in the loop.
5707 ret = btrfs_alloc_subpage(fs_info, &prealloc,
5708 BTRFS_SUBPAGE_METADATA);
5712 exists = ERR_PTR(ret);
5716 spin_lock(&mapping->private_lock);
5717 exists = grab_extent_buffer(fs_info, p);
5719 spin_unlock(&mapping->private_lock);
5722 mark_extent_buffer_accessed(exists, p);
5723 btrfs_free_subpage(prealloc);
5726 /* Should not fail, as we have preallocated the memory */
5727 ret = attach_extent_buffer_page(eb, p, prealloc);
5730 * To inform we have extra eb under allocation, so that
5731 * detach_extent_buffer_page() won't release the page private
5732 * when the eb hasn't yet been inserted into radix tree.
5734 * The ref will be decreased when the eb released the page, in
5735 * detach_extent_buffer_page().
5736 * Thus needs no special handling in error path.
5738 btrfs_page_inc_eb_refs(fs_info, p);
5739 spin_unlock(&mapping->private_lock);
5741 WARN_ON(btrfs_page_test_dirty(fs_info, p, eb->start, eb->len));
5743 if (!PageUptodate(p))
5747 * We can't unlock the pages just yet since the extent buffer
5748 * hasn't been properly inserted in the radix tree, this
5749 * opens a race with btree_releasepage which can free a page
5750 * while we are still filling in all pages for the buffer and
5755 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5757 ret = radix_tree_preload(GFP_NOFS);
5759 exists = ERR_PTR(ret);
5763 spin_lock(&fs_info->buffer_lock);
5764 ret = radix_tree_insert(&fs_info->buffer_radix,
5765 start >> fs_info->sectorsize_bits, eb);
5766 spin_unlock(&fs_info->buffer_lock);
5767 radix_tree_preload_end();
5768 if (ret == -EEXIST) {
5769 exists = find_extent_buffer(fs_info, start);
5775 /* add one reference for the tree */
5776 check_buffer_tree_ref(eb);
5777 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
5780 * Now it's safe to unlock the pages because any calls to
5781 * btree_releasepage will correctly detect that a page belongs to a
5782 * live buffer and won't free them prematurely.
5784 for (i = 0; i < num_pages; i++)
5785 unlock_page(eb->pages[i]);
5789 WARN_ON(!atomic_dec_and_test(&eb->refs));
5790 for (i = 0; i < num_pages; i++) {
5792 unlock_page(eb->pages[i]);
5795 btrfs_release_extent_buffer(eb);
5799 static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
5801 struct extent_buffer *eb =
5802 container_of(head, struct extent_buffer, rcu_head);
5804 __free_extent_buffer(eb);
5807 static int release_extent_buffer(struct extent_buffer *eb)
5808 __releases(&eb->refs_lock)
5810 lockdep_assert_held(&eb->refs_lock);
5812 WARN_ON(atomic_read(&eb->refs) == 0);
5813 if (atomic_dec_and_test(&eb->refs)) {
5814 if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
5815 struct btrfs_fs_info *fs_info = eb->fs_info;
5817 spin_unlock(&eb->refs_lock);
5819 spin_lock(&fs_info->buffer_lock);
5820 radix_tree_delete(&fs_info->buffer_radix,
5821 eb->start >> fs_info->sectorsize_bits);
5822 spin_unlock(&fs_info->buffer_lock);
5824 spin_unlock(&eb->refs_lock);
5827 btrfs_leak_debug_del(&eb->fs_info->eb_leak_lock, &eb->leak_list);
5828 /* Should be safe to release our pages at this point */
5829 btrfs_release_extent_buffer_pages(eb);
5830 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5831 if (unlikely(test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags))) {
5832 __free_extent_buffer(eb);
5836 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
5839 spin_unlock(&eb->refs_lock);
5844 void free_extent_buffer(struct extent_buffer *eb)
5852 refs = atomic_read(&eb->refs);
5853 if ((!test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) && refs <= 3)
5854 || (test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) &&
5857 old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
5862 spin_lock(&eb->refs_lock);
5863 if (atomic_read(&eb->refs) == 2 &&
5864 test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
5865 !extent_buffer_under_io(eb) &&
5866 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5867 atomic_dec(&eb->refs);
5870 * I know this is terrible, but it's temporary until we stop tracking
5871 * the uptodate bits and such for the extent buffers.
5873 release_extent_buffer(eb);
5876 void free_extent_buffer_stale(struct extent_buffer *eb)
5881 spin_lock(&eb->refs_lock);
5882 set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
5884 if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
5885 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5886 atomic_dec(&eb->refs);
5887 release_extent_buffer(eb);
5890 static void btree_clear_page_dirty(struct page *page)
5892 ASSERT(PageDirty(page));
5893 ASSERT(PageLocked(page));
5894 clear_page_dirty_for_io(page);
5895 xa_lock_irq(&page->mapping->i_pages);
5896 if (!PageDirty(page))
5897 __xa_clear_mark(&page->mapping->i_pages,
5898 page_index(page), PAGECACHE_TAG_DIRTY);
5899 xa_unlock_irq(&page->mapping->i_pages);
5902 static void clear_subpage_extent_buffer_dirty(const struct extent_buffer *eb)
5904 struct btrfs_fs_info *fs_info = eb->fs_info;
5905 struct page *page = eb->pages[0];
5908 /* btree_clear_page_dirty() needs page locked */
5910 last = btrfs_subpage_clear_and_test_dirty(fs_info, page, eb->start,
5913 btree_clear_page_dirty(page);
5915 WARN_ON(atomic_read(&eb->refs) == 0);
5918 void clear_extent_buffer_dirty(const struct extent_buffer *eb)
5924 if (eb->fs_info->sectorsize < PAGE_SIZE)
5925 return clear_subpage_extent_buffer_dirty(eb);
5927 num_pages = num_extent_pages(eb);
5929 for (i = 0; i < num_pages; i++) {
5930 page = eb->pages[i];
5931 if (!PageDirty(page))
5934 btree_clear_page_dirty(page);
5935 ClearPageError(page);
5938 WARN_ON(atomic_read(&eb->refs) == 0);
5941 bool set_extent_buffer_dirty(struct extent_buffer *eb)
5947 check_buffer_tree_ref(eb);
5949 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
5951 num_pages = num_extent_pages(eb);
5952 WARN_ON(atomic_read(&eb->refs) == 0);
5953 WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
5956 bool subpage = eb->fs_info->sectorsize < PAGE_SIZE;
5959 * For subpage case, we can have other extent buffers in the
5960 * same page, and in clear_subpage_extent_buffer_dirty() we
5961 * have to clear page dirty without subpage lock held.
5962 * This can cause race where our page gets dirty cleared after
5965 * Thankfully, clear_subpage_extent_buffer_dirty() has locked
5966 * its page for other reasons, we can use page lock to prevent
5970 lock_page(eb->pages[0]);
5971 for (i = 0; i < num_pages; i++)
5972 btrfs_page_set_dirty(eb->fs_info, eb->pages[i],
5973 eb->start, eb->len);
5975 unlock_page(eb->pages[0]);
5977 #ifdef CONFIG_BTRFS_DEBUG
5978 for (i = 0; i < num_pages; i++)
5979 ASSERT(PageDirty(eb->pages[i]));
5985 void clear_extent_buffer_uptodate(struct extent_buffer *eb)
5987 struct btrfs_fs_info *fs_info = eb->fs_info;
5992 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5993 num_pages = num_extent_pages(eb);
5994 for (i = 0; i < num_pages; i++) {
5995 page = eb->pages[i];
5997 btrfs_page_clear_uptodate(fs_info, page,
5998 eb->start, eb->len);
6002 void set_extent_buffer_uptodate(struct extent_buffer *eb)
6004 struct btrfs_fs_info *fs_info = eb->fs_info;
6009 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
6010 num_pages = num_extent_pages(eb);
6011 for (i = 0; i < num_pages; i++) {
6012 page = eb->pages[i];
6013 btrfs_page_set_uptodate(fs_info, page, eb->start, eb->len);
6017 static int read_extent_buffer_subpage(struct extent_buffer *eb, int wait,
6020 struct btrfs_fs_info *fs_info = eb->fs_info;
6021 struct extent_io_tree *io_tree;
6022 struct page *page = eb->pages[0];
6023 struct bio *bio = NULL;
6026 ASSERT(!test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags));
6027 ASSERT(PagePrivate(page));
6028 io_tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
6030 if (wait == WAIT_NONE) {
6031 ret = try_lock_extent(io_tree, eb->start,
6032 eb->start + eb->len - 1);
6036 ret = lock_extent(io_tree, eb->start, eb->start + eb->len - 1);
6042 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags) ||
6043 PageUptodate(page) ||
6044 btrfs_subpage_test_uptodate(fs_info, page, eb->start, eb->len)) {
6045 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
6046 unlock_extent(io_tree, eb->start, eb->start + eb->len - 1);
6050 clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
6051 eb->read_mirror = 0;
6052 atomic_set(&eb->io_pages, 1);
6053 check_buffer_tree_ref(eb);
6054 btrfs_subpage_clear_error(fs_info, page, eb->start, eb->len);
6056 ret = submit_extent_page(REQ_OP_READ | REQ_META, NULL, page, eb->start,
6057 eb->len, eb->start - page_offset(page), &bio,
6058 end_bio_extent_readpage, mirror_num, 0, 0,
6062 * In the endio function, if we hit something wrong we will
6063 * increase the io_pages, so here we need to decrease it for
6066 atomic_dec(&eb->io_pages);
6071 tmp = submit_one_bio(bio, mirror_num, 0);
6075 if (ret || wait != WAIT_COMPLETE)
6078 wait_extent_bit(io_tree, eb->start, eb->start + eb->len - 1, EXTENT_LOCKED);
6079 if (!test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
6084 int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num)
6090 int locked_pages = 0;
6091 int all_uptodate = 1;
6093 unsigned long num_reads = 0;
6094 struct bio *bio = NULL;
6095 unsigned long bio_flags = 0;
6097 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
6100 if (eb->fs_info->sectorsize < PAGE_SIZE)
6101 return read_extent_buffer_subpage(eb, wait, mirror_num);
6103 num_pages = num_extent_pages(eb);
6104 for (i = 0; i < num_pages; i++) {
6105 page = eb->pages[i];
6106 if (wait == WAIT_NONE) {
6108 * WAIT_NONE is only utilized by readahead. If we can't
6109 * acquire the lock atomically it means either the eb
6110 * is being read out or under modification.
6111 * Either way the eb will be or has been cached,
6112 * readahead can exit safely.
6114 if (!trylock_page(page))
6122 * We need to firstly lock all pages to make sure that
6123 * the uptodate bit of our pages won't be affected by
6124 * clear_extent_buffer_uptodate().
6126 for (i = 0; i < num_pages; i++) {
6127 page = eb->pages[i];
6128 if (!PageUptodate(page)) {
6135 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
6139 clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
6140 eb->read_mirror = 0;
6141 atomic_set(&eb->io_pages, num_reads);
6143 * It is possible for releasepage to clear the TREE_REF bit before we
6144 * set io_pages. See check_buffer_tree_ref for a more detailed comment.
6146 check_buffer_tree_ref(eb);
6147 for (i = 0; i < num_pages; i++) {
6148 page = eb->pages[i];
6150 if (!PageUptodate(page)) {
6152 atomic_dec(&eb->io_pages);
6157 ClearPageError(page);
6158 err = submit_extent_page(REQ_OP_READ | REQ_META, NULL,
6159 page, page_offset(page), PAGE_SIZE, 0,
6160 &bio, end_bio_extent_readpage,
6161 mirror_num, 0, 0, false);
6164 * We failed to submit the bio so it's the
6165 * caller's responsibility to perform cleanup
6166 * i.e unlock page/set error bit.
6171 atomic_dec(&eb->io_pages);
6179 err = submit_one_bio(bio, mirror_num, bio_flags);
6184 if (ret || wait != WAIT_COMPLETE)
6187 for (i = 0; i < num_pages; i++) {
6188 page = eb->pages[i];
6189 wait_on_page_locked(page);
6190 if (!PageUptodate(page))
6197 while (locked_pages > 0) {
6199 page = eb->pages[locked_pages];
6205 static bool report_eb_range(const struct extent_buffer *eb, unsigned long start,
6208 btrfs_warn(eb->fs_info,
6209 "access to eb bytenr %llu len %lu out of range start %lu len %lu",
6210 eb->start, eb->len, start, len);
6211 WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
6217 * Check if the [start, start + len) range is valid before reading/writing
6219 * NOTE: @start and @len are offset inside the eb, not logical address.
6221 * Caller should not touch the dst/src memory if this function returns error.
6223 static inline int check_eb_range(const struct extent_buffer *eb,
6224 unsigned long start, unsigned long len)
6226 unsigned long offset;
6228 /* start, start + len should not go beyond eb->len nor overflow */
6229 if (unlikely(check_add_overflow(start, len, &offset) || offset > eb->len))
6230 return report_eb_range(eb, start, len);
6235 void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
6236 unsigned long start, unsigned long len)
6242 char *dst = (char *)dstv;
6243 unsigned long i = get_eb_page_index(start);
6245 if (check_eb_range(eb, start, len))
6248 offset = get_eb_offset_in_page(eb, start);
6251 page = eb->pages[i];
6253 cur = min(len, (PAGE_SIZE - offset));
6254 kaddr = page_address(page);
6255 memcpy(dst, kaddr + offset, cur);
6264 int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
6266 unsigned long start, unsigned long len)
6272 char __user *dst = (char __user *)dstv;
6273 unsigned long i = get_eb_page_index(start);
6276 WARN_ON(start > eb->len);
6277 WARN_ON(start + len > eb->start + eb->len);
6279 offset = get_eb_offset_in_page(eb, start);
6282 page = eb->pages[i];
6284 cur = min(len, (PAGE_SIZE - offset));
6285 kaddr = page_address(page);
6286 if (copy_to_user_nofault(dst, kaddr + offset, cur)) {
6300 int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
6301 unsigned long start, unsigned long len)
6307 char *ptr = (char *)ptrv;
6308 unsigned long i = get_eb_page_index(start);
6311 if (check_eb_range(eb, start, len))
6314 offset = get_eb_offset_in_page(eb, start);
6317 page = eb->pages[i];
6319 cur = min(len, (PAGE_SIZE - offset));
6321 kaddr = page_address(page);
6322 ret = memcmp(ptr, kaddr + offset, cur);
6335 * Check that the extent buffer is uptodate.
6337 * For regular sector size == PAGE_SIZE case, check if @page is uptodate.
6338 * For subpage case, check if the range covered by the eb has EXTENT_UPTODATE.
6340 static void assert_eb_page_uptodate(const struct extent_buffer *eb,
6343 struct btrfs_fs_info *fs_info = eb->fs_info;
6345 if (fs_info->sectorsize < PAGE_SIZE) {
6348 uptodate = btrfs_subpage_test_uptodate(fs_info, page,
6349 eb->start, eb->len);
6352 WARN_ON(!PageUptodate(page));
6356 void write_extent_buffer_chunk_tree_uuid(const struct extent_buffer *eb,
6361 assert_eb_page_uptodate(eb, eb->pages[0]);
6362 kaddr = page_address(eb->pages[0]) + get_eb_offset_in_page(eb, 0);
6363 memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,
6367 void write_extent_buffer_fsid(const struct extent_buffer *eb, const void *srcv)
6371 assert_eb_page_uptodate(eb, eb->pages[0]);
6372 kaddr = page_address(eb->pages[0]) + get_eb_offset_in_page(eb, 0);
6373 memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,
6377 void write_extent_buffer(const struct extent_buffer *eb, const void *srcv,
6378 unsigned long start, unsigned long len)
6384 char *src = (char *)srcv;
6385 unsigned long i = get_eb_page_index(start);
6387 WARN_ON(test_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags));
6389 if (check_eb_range(eb, start, len))
6392 offset = get_eb_offset_in_page(eb, start);
6395 page = eb->pages[i];
6396 assert_eb_page_uptodate(eb, page);
6398 cur = min(len, PAGE_SIZE - offset);
6399 kaddr = page_address(page);
6400 memcpy(kaddr + offset, src, cur);
6409 void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
6416 unsigned long i = get_eb_page_index(start);
6418 if (check_eb_range(eb, start, len))
6421 offset = get_eb_offset_in_page(eb, start);
6424 page = eb->pages[i];
6425 assert_eb_page_uptodate(eb, page);
6427 cur = min(len, PAGE_SIZE - offset);
6428 kaddr = page_address(page);
6429 memset(kaddr + offset, 0, cur);
6437 void copy_extent_buffer_full(const struct extent_buffer *dst,
6438 const struct extent_buffer *src)
6443 ASSERT(dst->len == src->len);
6445 if (dst->fs_info->sectorsize == PAGE_SIZE) {
6446 num_pages = num_extent_pages(dst);
6447 for (i = 0; i < num_pages; i++)
6448 copy_page(page_address(dst->pages[i]),
6449 page_address(src->pages[i]));
6451 size_t src_offset = get_eb_offset_in_page(src, 0);
6452 size_t dst_offset = get_eb_offset_in_page(dst, 0);
6454 ASSERT(src->fs_info->sectorsize < PAGE_SIZE);
6455 memcpy(page_address(dst->pages[0]) + dst_offset,
6456 page_address(src->pages[0]) + src_offset,
6461 void copy_extent_buffer(const struct extent_buffer *dst,
6462 const struct extent_buffer *src,
6463 unsigned long dst_offset, unsigned long src_offset,
6466 u64 dst_len = dst->len;
6471 unsigned long i = get_eb_page_index(dst_offset);
6473 if (check_eb_range(dst, dst_offset, len) ||
6474 check_eb_range(src, src_offset, len))
6477 WARN_ON(src->len != dst_len);
6479 offset = get_eb_offset_in_page(dst, dst_offset);
6482 page = dst->pages[i];
6483 assert_eb_page_uptodate(dst, page);
6485 cur = min(len, (unsigned long)(PAGE_SIZE - offset));
6487 kaddr = page_address(page);
6488 read_extent_buffer(src, kaddr + offset, src_offset, cur);
6498 * eb_bitmap_offset() - calculate the page and offset of the byte containing the
6500 * @eb: the extent buffer
6501 * @start: offset of the bitmap item in the extent buffer
6503 * @page_index: return index of the page in the extent buffer that contains the
6505 * @page_offset: return offset into the page given by page_index
6507 * This helper hides the ugliness of finding the byte in an extent buffer which
6508 * contains a given bit.
6510 static inline void eb_bitmap_offset(const struct extent_buffer *eb,
6511 unsigned long start, unsigned long nr,
6512 unsigned long *page_index,
6513 size_t *page_offset)
6515 size_t byte_offset = BIT_BYTE(nr);
6519 * The byte we want is the offset of the extent buffer + the offset of
6520 * the bitmap item in the extent buffer + the offset of the byte in the
6523 offset = start + offset_in_page(eb->start) + byte_offset;
6525 *page_index = offset >> PAGE_SHIFT;
6526 *page_offset = offset_in_page(offset);
6530 * extent_buffer_test_bit - determine whether a bit in a bitmap item is set
6531 * @eb: the extent buffer
6532 * @start: offset of the bitmap item in the extent buffer
6533 * @nr: bit number to test
6535 int extent_buffer_test_bit(const struct extent_buffer *eb, unsigned long start,
6543 eb_bitmap_offset(eb, start, nr, &i, &offset);
6544 page = eb->pages[i];
6545 assert_eb_page_uptodate(eb, page);
6546 kaddr = page_address(page);
6547 return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
6551 * extent_buffer_bitmap_set - set an area of a bitmap
6552 * @eb: the extent buffer
6553 * @start: offset of the bitmap item in the extent buffer
6554 * @pos: bit number of the first bit
6555 * @len: number of bits to set
6557 void extent_buffer_bitmap_set(const struct extent_buffer *eb, unsigned long start,
6558 unsigned long pos, unsigned long len)
6564 const unsigned int size = pos + len;
6565 int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
6566 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
6568 eb_bitmap_offset(eb, start, pos, &i, &offset);
6569 page = eb->pages[i];
6570 assert_eb_page_uptodate(eb, page);
6571 kaddr = page_address(page);
6573 while (len >= bits_to_set) {
6574 kaddr[offset] |= mask_to_set;
6576 bits_to_set = BITS_PER_BYTE;
6578 if (++offset >= PAGE_SIZE && len > 0) {
6580 page = eb->pages[++i];
6581 assert_eb_page_uptodate(eb, page);
6582 kaddr = page_address(page);
6586 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
6587 kaddr[offset] |= mask_to_set;
6593 * extent_buffer_bitmap_clear - clear an area of a bitmap
6594 * @eb: the extent buffer
6595 * @start: offset of the bitmap item in the extent buffer
6596 * @pos: bit number of the first bit
6597 * @len: number of bits to clear
6599 void extent_buffer_bitmap_clear(const struct extent_buffer *eb,
6600 unsigned long start, unsigned long pos,
6607 const unsigned int size = pos + len;
6608 int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
6609 u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
6611 eb_bitmap_offset(eb, start, pos, &i, &offset);
6612 page = eb->pages[i];
6613 assert_eb_page_uptodate(eb, page);
6614 kaddr = page_address(page);
6616 while (len >= bits_to_clear) {
6617 kaddr[offset] &= ~mask_to_clear;
6618 len -= bits_to_clear;
6619 bits_to_clear = BITS_PER_BYTE;
6621 if (++offset >= PAGE_SIZE && len > 0) {
6623 page = eb->pages[++i];
6624 assert_eb_page_uptodate(eb, page);
6625 kaddr = page_address(page);
6629 mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
6630 kaddr[offset] &= ~mask_to_clear;
6634 static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
6636 unsigned long distance = (src > dst) ? src - dst : dst - src;
6637 return distance < len;
6640 static void copy_pages(struct page *dst_page, struct page *src_page,
6641 unsigned long dst_off, unsigned long src_off,
6644 char *dst_kaddr = page_address(dst_page);
6646 int must_memmove = 0;
6648 if (dst_page != src_page) {
6649 src_kaddr = page_address(src_page);
6651 src_kaddr = dst_kaddr;
6652 if (areas_overlap(src_off, dst_off, len))
6657 memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
6659 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
6662 void memcpy_extent_buffer(const struct extent_buffer *dst,
6663 unsigned long dst_offset, unsigned long src_offset,
6667 size_t dst_off_in_page;
6668 size_t src_off_in_page;
6669 unsigned long dst_i;
6670 unsigned long src_i;
6672 if (check_eb_range(dst, dst_offset, len) ||
6673 check_eb_range(dst, src_offset, len))
6677 dst_off_in_page = get_eb_offset_in_page(dst, dst_offset);
6678 src_off_in_page = get_eb_offset_in_page(dst, src_offset);
6680 dst_i = get_eb_page_index(dst_offset);
6681 src_i = get_eb_page_index(src_offset);
6683 cur = min(len, (unsigned long)(PAGE_SIZE -
6685 cur = min_t(unsigned long, cur,
6686 (unsigned long)(PAGE_SIZE - dst_off_in_page));
6688 copy_pages(dst->pages[dst_i], dst->pages[src_i],
6689 dst_off_in_page, src_off_in_page, cur);
6697 void memmove_extent_buffer(const struct extent_buffer *dst,
6698 unsigned long dst_offset, unsigned long src_offset,
6702 size_t dst_off_in_page;
6703 size_t src_off_in_page;
6704 unsigned long dst_end = dst_offset + len - 1;
6705 unsigned long src_end = src_offset + len - 1;
6706 unsigned long dst_i;
6707 unsigned long src_i;
6709 if (check_eb_range(dst, dst_offset, len) ||
6710 check_eb_range(dst, src_offset, len))
6712 if (dst_offset < src_offset) {
6713 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
6717 dst_i = get_eb_page_index(dst_end);
6718 src_i = get_eb_page_index(src_end);
6720 dst_off_in_page = get_eb_offset_in_page(dst, dst_end);
6721 src_off_in_page = get_eb_offset_in_page(dst, src_end);
6723 cur = min_t(unsigned long, len, src_off_in_page + 1);
6724 cur = min(cur, dst_off_in_page + 1);
6725 copy_pages(dst->pages[dst_i], dst->pages[src_i],
6726 dst_off_in_page - cur + 1,
6727 src_off_in_page - cur + 1, cur);
6735 static struct extent_buffer *get_next_extent_buffer(
6736 struct btrfs_fs_info *fs_info, struct page *page, u64 bytenr)
6738 struct extent_buffer *gang[BTRFS_SUBPAGE_BITMAP_SIZE];
6739 struct extent_buffer *found = NULL;
6740 u64 page_start = page_offset(page);
6744 ASSERT(in_range(bytenr, page_start, PAGE_SIZE));
6745 ASSERT(PAGE_SIZE / fs_info->nodesize <= BTRFS_SUBPAGE_BITMAP_SIZE);
6746 lockdep_assert_held(&fs_info->buffer_lock);
6748 ret = radix_tree_gang_lookup(&fs_info->buffer_radix, (void **)gang,
6749 bytenr >> fs_info->sectorsize_bits,
6750 PAGE_SIZE / fs_info->nodesize);
6751 for (i = 0; i < ret; i++) {
6752 /* Already beyond page end */
6753 if (gang[i]->start >= page_start + PAGE_SIZE)
6756 if (gang[i]->start >= bytenr) {
6764 static int try_release_subpage_extent_buffer(struct page *page)
6766 struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
6767 u64 cur = page_offset(page);
6768 const u64 end = page_offset(page) + PAGE_SIZE;
6772 struct extent_buffer *eb = NULL;
6775 * Unlike try_release_extent_buffer() which uses page->private
6776 * to grab buffer, for subpage case we rely on radix tree, thus
6777 * we need to ensure radix tree consistency.
6779 * We also want an atomic snapshot of the radix tree, thus go
6780 * with spinlock rather than RCU.
6782 spin_lock(&fs_info->buffer_lock);
6783 eb = get_next_extent_buffer(fs_info, page, cur);
6785 /* No more eb in the page range after or at cur */
6786 spin_unlock(&fs_info->buffer_lock);
6789 cur = eb->start + eb->len;
6792 * The same as try_release_extent_buffer(), to ensure the eb
6793 * won't disappear out from under us.
6795 spin_lock(&eb->refs_lock);
6796 if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
6797 spin_unlock(&eb->refs_lock);
6798 spin_unlock(&fs_info->buffer_lock);
6801 spin_unlock(&fs_info->buffer_lock);
6804 * If tree ref isn't set then we know the ref on this eb is a
6805 * real ref, so just return, this eb will likely be freed soon
6808 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
6809 spin_unlock(&eb->refs_lock);
6814 * Here we don't care about the return value, we will always
6815 * check the page private at the end. And
6816 * release_extent_buffer() will release the refs_lock.
6818 release_extent_buffer(eb);
6821 * Finally to check if we have cleared page private, as if we have
6822 * released all ebs in the page, the page private should be cleared now.
6824 spin_lock(&page->mapping->private_lock);
6825 if (!PagePrivate(page))
6829 spin_unlock(&page->mapping->private_lock);
6834 int try_release_extent_buffer(struct page *page)
6836 struct extent_buffer *eb;
6838 if (btrfs_sb(page->mapping->host->i_sb)->sectorsize < PAGE_SIZE)
6839 return try_release_subpage_extent_buffer(page);
6842 * We need to make sure nobody is changing page->private, as we rely on
6843 * page->private as the pointer to extent buffer.
6845 spin_lock(&page->mapping->private_lock);
6846 if (!PagePrivate(page)) {
6847 spin_unlock(&page->mapping->private_lock);
6851 eb = (struct extent_buffer *)page->private;
6855 * This is a little awful but should be ok, we need to make sure that
6856 * the eb doesn't disappear out from under us while we're looking at
6859 spin_lock(&eb->refs_lock);
6860 if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
6861 spin_unlock(&eb->refs_lock);
6862 spin_unlock(&page->mapping->private_lock);
6865 spin_unlock(&page->mapping->private_lock);
6868 * If tree ref isn't set then we know the ref on this eb is a real ref,
6869 * so just return, this page will likely be freed soon anyway.
6871 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
6872 spin_unlock(&eb->refs_lock);
6876 return release_extent_buffer(eb);
6880 * btrfs_readahead_tree_block - attempt to readahead a child block
6881 * @fs_info: the fs_info
6882 * @bytenr: bytenr to read
6883 * @owner_root: objectid of the root that owns this eb
6884 * @gen: generation for the uptodate check, can be 0
6885 * @level: level for the eb
6887 * Attempt to readahead a tree block at @bytenr. If @gen is 0 then we do a
6888 * normal uptodate check of the eb, without checking the generation. If we have
6889 * to read the block we will not block on anything.
6891 void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
6892 u64 bytenr, u64 owner_root, u64 gen, int level)
6894 struct extent_buffer *eb;
6897 eb = btrfs_find_create_tree_block(fs_info, bytenr, owner_root, level);
6901 if (btrfs_buffer_uptodate(eb, gen, 1)) {
6902 free_extent_buffer(eb);
6906 ret = read_extent_buffer_pages(eb, WAIT_NONE, 0);
6908 free_extent_buffer_stale(eb);
6910 free_extent_buffer(eb);
6914 * btrfs_readahead_node_child - readahead a node's child block
6915 * @node: parent node we're reading from
6916 * @slot: slot in the parent node for the child we want to read
6918 * A helper for btrfs_readahead_tree_block, we simply read the bytenr pointed at
6919 * the slot in the node provided.
6921 void btrfs_readahead_node_child(struct extent_buffer *node, int slot)
6923 btrfs_readahead_tree_block(node->fs_info,
6924 btrfs_node_blockptr(node, slot),
6925 btrfs_header_owner(node),
6926 btrfs_node_ptr_generation(node, slot),
6927 btrfs_header_level(node) - 1);