1 #include <linux/bitops.h>
2 #include <linux/slab.h>
5 #include <linux/pagemap.h>
6 #include <linux/page-flags.h>
7 #include <linux/spinlock.h>
8 #include <linux/blkdev.h>
9 #include <linux/swap.h>
10 #include <linux/writeback.h>
11 #include <linux/pagevec.h>
12 #include <linux/prefetch.h>
13 #include <linux/cleancache.h>
14 #include "extent_io.h"
15 #include "extent_map.h"
17 #include "btrfs_inode.h"
19 #include "check-integrity.h"
21 #include "rcu-string.h"
24 static struct kmem_cache *extent_state_cache;
25 static struct kmem_cache *extent_buffer_cache;
26 static struct bio_set *btrfs_bioset;
28 static inline bool extent_state_in_tree(const struct extent_state *state)
30 return !RB_EMPTY_NODE(&state->rb_node);
33 #ifdef CONFIG_BTRFS_DEBUG
34 static LIST_HEAD(buffers);
35 static LIST_HEAD(states);
37 static DEFINE_SPINLOCK(leak_lock);
40 void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
44 spin_lock_irqsave(&leak_lock, flags);
46 spin_unlock_irqrestore(&leak_lock, flags);
50 void btrfs_leak_debug_del(struct list_head *entry)
54 spin_lock_irqsave(&leak_lock, flags);
56 spin_unlock_irqrestore(&leak_lock, flags);
60 void btrfs_leak_debug_check(void)
62 struct extent_state *state;
63 struct extent_buffer *eb;
65 while (!list_empty(&states)) {
66 state = list_entry(states.next, struct extent_state, leak_list);
67 pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
68 state->start, state->end, state->state,
69 extent_state_in_tree(state),
70 atomic_read(&state->refs));
71 list_del(&state->leak_list);
72 kmem_cache_free(extent_state_cache, state);
75 while (!list_empty(&buffers)) {
76 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
77 printk(KERN_ERR "BTRFS: buffer leak start %llu len %lu "
79 eb->start, eb->len, atomic_read(&eb->refs));
80 list_del(&eb->leak_list);
81 kmem_cache_free(extent_buffer_cache, eb);
85 #define btrfs_debug_check_extent_io_range(tree, start, end) \
86 __btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
87 static inline void __btrfs_debug_check_extent_io_range(const char *caller,
88 struct extent_io_tree *tree, u64 start, u64 end)
96 inode = tree->mapping->host;
97 isize = i_size_read(inode);
98 if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
99 printk_ratelimited(KERN_DEBUG
100 "BTRFS: %s: ino %llu isize %llu odd range [%llu,%llu]\n",
101 caller, btrfs_ino(inode), isize, start, end);
105 #define btrfs_leak_debug_add(new, head) do {} while (0)
106 #define btrfs_leak_debug_del(entry) do {} while (0)
107 #define btrfs_leak_debug_check() do {} while (0)
108 #define btrfs_debug_check_extent_io_range(c, s, e) do {} while (0)
111 #define BUFFER_LRU_MAX 64
116 struct rb_node rb_node;
119 struct extent_page_data {
121 struct extent_io_tree *tree;
122 get_extent_t *get_extent;
123 unsigned long bio_flags;
125 /* tells writepage not to lock the state bits for this range
126 * it still does the unlocking
128 unsigned int extent_locked:1;
130 /* tells the submit_bio code to use a WRITE_SYNC */
131 unsigned int sync_io:1;
134 static noinline void flush_write_bio(void *data);
135 static inline struct btrfs_fs_info *
136 tree_fs_info(struct extent_io_tree *tree)
140 return btrfs_sb(tree->mapping->host->i_sb);
143 int __init extent_io_init(void)
145 extent_state_cache = kmem_cache_create("btrfs_extent_state",
146 sizeof(struct extent_state), 0,
147 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
148 if (!extent_state_cache)
151 extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
152 sizeof(struct extent_buffer), 0,
153 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
154 if (!extent_buffer_cache)
155 goto free_state_cache;
157 btrfs_bioset = bioset_create(BIO_POOL_SIZE,
158 offsetof(struct btrfs_io_bio, bio));
160 goto free_buffer_cache;
162 if (bioset_integrity_create(btrfs_bioset, BIO_POOL_SIZE))
168 bioset_free(btrfs_bioset);
172 kmem_cache_destroy(extent_buffer_cache);
173 extent_buffer_cache = NULL;
176 kmem_cache_destroy(extent_state_cache);
177 extent_state_cache = NULL;
181 void extent_io_exit(void)
183 btrfs_leak_debug_check();
186 * Make sure all delayed rcu free are flushed before we
190 if (extent_state_cache)
191 kmem_cache_destroy(extent_state_cache);
192 if (extent_buffer_cache)
193 kmem_cache_destroy(extent_buffer_cache);
195 bioset_free(btrfs_bioset);
198 void extent_io_tree_init(struct extent_io_tree *tree,
199 struct address_space *mapping)
201 tree->state = RB_ROOT;
203 tree->dirty_bytes = 0;
204 spin_lock_init(&tree->lock);
205 tree->mapping = mapping;
208 static struct extent_state *alloc_extent_state(gfp_t mask)
210 struct extent_state *state;
212 state = kmem_cache_alloc(extent_state_cache, mask);
217 RB_CLEAR_NODE(&state->rb_node);
218 btrfs_leak_debug_add(&state->leak_list, &states);
219 atomic_set(&state->refs, 1);
220 init_waitqueue_head(&state->wq);
221 trace_alloc_extent_state(state, mask, _RET_IP_);
225 void free_extent_state(struct extent_state *state)
229 if (atomic_dec_and_test(&state->refs)) {
230 WARN_ON(extent_state_in_tree(state));
231 btrfs_leak_debug_del(&state->leak_list);
232 trace_free_extent_state(state, _RET_IP_);
233 kmem_cache_free(extent_state_cache, state);
237 static struct rb_node *tree_insert(struct rb_root *root,
238 struct rb_node *search_start,
240 struct rb_node *node,
241 struct rb_node ***p_in,
242 struct rb_node **parent_in)
245 struct rb_node *parent = NULL;
246 struct tree_entry *entry;
248 if (p_in && parent_in) {
254 p = search_start ? &search_start : &root->rb_node;
257 entry = rb_entry(parent, struct tree_entry, rb_node);
259 if (offset < entry->start)
261 else if (offset > entry->end)
268 rb_link_node(node, parent, p);
269 rb_insert_color(node, root);
273 static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
274 struct rb_node **prev_ret,
275 struct rb_node **next_ret,
276 struct rb_node ***p_ret,
277 struct rb_node **parent_ret)
279 struct rb_root *root = &tree->state;
280 struct rb_node **n = &root->rb_node;
281 struct rb_node *prev = NULL;
282 struct rb_node *orig_prev = NULL;
283 struct tree_entry *entry;
284 struct tree_entry *prev_entry = NULL;
288 entry = rb_entry(prev, struct tree_entry, rb_node);
291 if (offset < entry->start)
293 else if (offset > entry->end)
306 while (prev && offset > prev_entry->end) {
307 prev = rb_next(prev);
308 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
315 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
316 while (prev && offset < prev_entry->start) {
317 prev = rb_prev(prev);
318 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
325 static inline struct rb_node *
326 tree_search_for_insert(struct extent_io_tree *tree,
328 struct rb_node ***p_ret,
329 struct rb_node **parent_ret)
331 struct rb_node *prev = NULL;
334 ret = __etree_search(tree, offset, &prev, NULL, p_ret, parent_ret);
340 static inline struct rb_node *tree_search(struct extent_io_tree *tree,
343 return tree_search_for_insert(tree, offset, NULL, NULL);
346 static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
347 struct extent_state *other)
349 if (tree->ops && tree->ops->merge_extent_hook)
350 tree->ops->merge_extent_hook(tree->mapping->host, new,
355 * utility function to look for merge candidates inside a given range.
356 * Any extents with matching state are merged together into a single
357 * extent in the tree. Extents with EXTENT_IO in their state field
358 * are not merged because the end_io handlers need to be able to do
359 * operations on them without sleeping (or doing allocations/splits).
361 * This should be called with the tree lock held.
363 static void merge_state(struct extent_io_tree *tree,
364 struct extent_state *state)
366 struct extent_state *other;
367 struct rb_node *other_node;
369 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
372 other_node = rb_prev(&state->rb_node);
374 other = rb_entry(other_node, struct extent_state, rb_node);
375 if (other->end == state->start - 1 &&
376 other->state == state->state) {
377 merge_cb(tree, state, other);
378 state->start = other->start;
379 rb_erase(&other->rb_node, &tree->state);
380 RB_CLEAR_NODE(&other->rb_node);
381 free_extent_state(other);
384 other_node = rb_next(&state->rb_node);
386 other = rb_entry(other_node, struct extent_state, rb_node);
387 if (other->start == state->end + 1 &&
388 other->state == state->state) {
389 merge_cb(tree, state, other);
390 state->end = other->end;
391 rb_erase(&other->rb_node, &tree->state);
392 RB_CLEAR_NODE(&other->rb_node);
393 free_extent_state(other);
398 static void set_state_cb(struct extent_io_tree *tree,
399 struct extent_state *state, unsigned *bits)
401 if (tree->ops && tree->ops->set_bit_hook)
402 tree->ops->set_bit_hook(tree->mapping->host, state, bits);
405 static void clear_state_cb(struct extent_io_tree *tree,
406 struct extent_state *state, unsigned *bits)
408 if (tree->ops && tree->ops->clear_bit_hook)
409 tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
412 static void set_state_bits(struct extent_io_tree *tree,
413 struct extent_state *state, unsigned *bits);
416 * insert an extent_state struct into the tree. 'bits' are set on the
417 * struct before it is inserted.
419 * This may return -EEXIST if the extent is already there, in which case the
420 * state struct is freed.
422 * The tree lock is not taken internally. This is a utility function and
423 * probably isn't what you want to call (see set/clear_extent_bit).
425 static int insert_state(struct extent_io_tree *tree,
426 struct extent_state *state, u64 start, u64 end,
428 struct rb_node **parent,
431 struct rb_node *node;
434 WARN(1, KERN_ERR "BTRFS: end < start %llu %llu\n",
436 state->start = start;
439 set_state_bits(tree, state, bits);
441 node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
443 struct extent_state *found;
444 found = rb_entry(node, struct extent_state, rb_node);
445 printk(KERN_ERR "BTRFS: found node %llu %llu on insert of "
447 found->start, found->end, start, end);
450 merge_state(tree, state);
454 static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
457 if (tree->ops && tree->ops->split_extent_hook)
458 tree->ops->split_extent_hook(tree->mapping->host, orig, split);
462 * split a given extent state struct in two, inserting the preallocated
463 * struct 'prealloc' as the newly created second half. 'split' indicates an
464 * offset inside 'orig' where it should be split.
467 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
468 * are two extent state structs in the tree:
469 * prealloc: [orig->start, split - 1]
470 * orig: [ split, orig->end ]
472 * The tree locks are not taken by this function. They need to be held
475 static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
476 struct extent_state *prealloc, u64 split)
478 struct rb_node *node;
480 split_cb(tree, orig, split);
482 prealloc->start = orig->start;
483 prealloc->end = split - 1;
484 prealloc->state = orig->state;
487 node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
488 &prealloc->rb_node, NULL, NULL);
490 free_extent_state(prealloc);
496 static struct extent_state *next_state(struct extent_state *state)
498 struct rb_node *next = rb_next(&state->rb_node);
500 return rb_entry(next, struct extent_state, rb_node);
506 * utility function to clear some bits in an extent state struct.
507 * it will optionally wake up any one waiting on this state (wake == 1).
509 * If no bits are set on the state struct after clearing things, the
510 * struct is freed and removed from the tree
512 static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
513 struct extent_state *state,
514 unsigned *bits, int wake)
516 struct extent_state *next;
517 unsigned bits_to_clear = *bits & ~EXTENT_CTLBITS;
519 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
520 u64 range = state->end - state->start + 1;
521 WARN_ON(range > tree->dirty_bytes);
522 tree->dirty_bytes -= range;
524 clear_state_cb(tree, state, bits);
525 state->state &= ~bits_to_clear;
528 if (state->state == 0) {
529 next = next_state(state);
530 if (extent_state_in_tree(state)) {
531 rb_erase(&state->rb_node, &tree->state);
532 RB_CLEAR_NODE(&state->rb_node);
533 free_extent_state(state);
538 merge_state(tree, state);
539 next = next_state(state);
544 static struct extent_state *
545 alloc_extent_state_atomic(struct extent_state *prealloc)
548 prealloc = alloc_extent_state(GFP_ATOMIC);
553 static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
555 btrfs_panic(tree_fs_info(tree), err, "Locking error: "
556 "Extent tree was modified by another "
557 "thread while locked.");
561 * clear some bits on a range in the tree. This may require splitting
562 * or inserting elements in the tree, so the gfp mask is used to
563 * indicate which allocations or sleeping are allowed.
565 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
566 * the given range from the tree regardless of state (ie for truncate).
568 * the range [start, end] is inclusive.
570 * This takes the tree lock, and returns 0 on success and < 0 on error.
572 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
573 unsigned bits, int wake, int delete,
574 struct extent_state **cached_state,
577 struct extent_state *state;
578 struct extent_state *cached;
579 struct extent_state *prealloc = NULL;
580 struct rb_node *node;
585 btrfs_debug_check_extent_io_range(tree, start, end);
587 if (bits & EXTENT_DELALLOC)
588 bits |= EXTENT_NORESERVE;
591 bits |= ~EXTENT_CTLBITS;
592 bits |= EXTENT_FIRST_DELALLOC;
594 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
597 if (!prealloc && (mask & __GFP_WAIT)) {
599 * Don't care for allocation failure here because we might end
600 * up not needing the pre-allocated extent state at all, which
601 * is the case if we only have in the tree extent states that
602 * cover our input range and don't cover too any other range.
603 * If we end up needing a new extent state we allocate it later.
605 prealloc = alloc_extent_state(mask);
608 spin_lock(&tree->lock);
610 cached = *cached_state;
613 *cached_state = NULL;
617 if (cached && extent_state_in_tree(cached) &&
618 cached->start <= start && cached->end > start) {
620 atomic_dec(&cached->refs);
625 free_extent_state(cached);
628 * this search will find the extents that end after
631 node = tree_search(tree, start);
634 state = rb_entry(node, struct extent_state, rb_node);
636 if (state->start > end)
638 WARN_ON(state->end < start);
639 last_end = state->end;
641 /* the state doesn't have the wanted bits, go ahead */
642 if (!(state->state & bits)) {
643 state = next_state(state);
648 * | ---- desired range ---- |
650 * | ------------- state -------------- |
652 * We need to split the extent we found, and may flip
653 * bits on second half.
655 * If the extent we found extends past our range, we
656 * just split and search again. It'll get split again
657 * the next time though.
659 * If the extent we found is inside our range, we clear
660 * the desired bit on it.
663 if (state->start < start) {
664 prealloc = alloc_extent_state_atomic(prealloc);
666 err = split_state(tree, state, prealloc, start);
668 extent_io_tree_panic(tree, err);
673 if (state->end <= end) {
674 state = clear_state_bit(tree, state, &bits, wake);
680 * | ---- desired range ---- |
682 * We need to split the extent, and clear the bit
685 if (state->start <= end && state->end > end) {
686 prealloc = alloc_extent_state_atomic(prealloc);
688 err = split_state(tree, state, prealloc, end + 1);
690 extent_io_tree_panic(tree, err);
695 clear_state_bit(tree, prealloc, &bits, wake);
701 state = clear_state_bit(tree, state, &bits, wake);
703 if (last_end == (u64)-1)
705 start = last_end + 1;
706 if (start <= end && state && !need_resched())
711 spin_unlock(&tree->lock);
713 free_extent_state(prealloc);
720 spin_unlock(&tree->lock);
721 if (mask & __GFP_WAIT)
726 static void wait_on_state(struct extent_io_tree *tree,
727 struct extent_state *state)
728 __releases(tree->lock)
729 __acquires(tree->lock)
732 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
733 spin_unlock(&tree->lock);
735 spin_lock(&tree->lock);
736 finish_wait(&state->wq, &wait);
740 * waits for one or more bits to clear on a range in the state tree.
741 * The range [start, end] is inclusive.
742 * The tree lock is taken by this function
744 static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
747 struct extent_state *state;
748 struct rb_node *node;
750 btrfs_debug_check_extent_io_range(tree, start, end);
752 spin_lock(&tree->lock);
756 * this search will find all the extents that end after
759 node = tree_search(tree, start);
764 state = rb_entry(node, struct extent_state, rb_node);
766 if (state->start > end)
769 if (state->state & bits) {
770 start = state->start;
771 atomic_inc(&state->refs);
772 wait_on_state(tree, state);
773 free_extent_state(state);
776 start = state->end + 1;
781 if (!cond_resched_lock(&tree->lock)) {
782 node = rb_next(node);
787 spin_unlock(&tree->lock);
790 static void set_state_bits(struct extent_io_tree *tree,
791 struct extent_state *state,
794 unsigned bits_to_set = *bits & ~EXTENT_CTLBITS;
796 set_state_cb(tree, state, bits);
797 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
798 u64 range = state->end - state->start + 1;
799 tree->dirty_bytes += range;
801 state->state |= bits_to_set;
804 static void cache_state_if_flags(struct extent_state *state,
805 struct extent_state **cached_ptr,
808 if (cached_ptr && !(*cached_ptr)) {
809 if (!flags || (state->state & flags)) {
811 atomic_inc(&state->refs);
816 static void cache_state(struct extent_state *state,
817 struct extent_state **cached_ptr)
819 return cache_state_if_flags(state, cached_ptr,
820 EXTENT_IOBITS | EXTENT_BOUNDARY);
824 * set some bits on a range in the tree. This may require allocations or
825 * sleeping, so the gfp mask is used to indicate what is allowed.
827 * If any of the exclusive bits are set, this will fail with -EEXIST if some
828 * part of the range already has the desired bits set. The start of the
829 * existing range is returned in failed_start in this case.
831 * [start, end] is inclusive This takes the tree lock.
834 static int __must_check
835 __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
836 unsigned bits, unsigned exclusive_bits,
837 u64 *failed_start, struct extent_state **cached_state,
840 struct extent_state *state;
841 struct extent_state *prealloc = NULL;
842 struct rb_node *node;
844 struct rb_node *parent;
849 btrfs_debug_check_extent_io_range(tree, start, end);
851 bits |= EXTENT_FIRST_DELALLOC;
853 if (!prealloc && (mask & __GFP_WAIT)) {
854 prealloc = alloc_extent_state(mask);
858 spin_lock(&tree->lock);
859 if (cached_state && *cached_state) {
860 state = *cached_state;
861 if (state->start <= start && state->end > start &&
862 extent_state_in_tree(state)) {
863 node = &state->rb_node;
868 * this search will find all the extents that end after
871 node = tree_search_for_insert(tree, start, &p, &parent);
873 prealloc = alloc_extent_state_atomic(prealloc);
875 err = insert_state(tree, prealloc, start, end,
878 extent_io_tree_panic(tree, err);
880 cache_state(prealloc, cached_state);
884 state = rb_entry(node, struct extent_state, rb_node);
886 last_start = state->start;
887 last_end = state->end;
890 * | ---- desired range ---- |
893 * Just lock what we found and keep going
895 if (state->start == start && state->end <= end) {
896 if (state->state & exclusive_bits) {
897 *failed_start = state->start;
902 set_state_bits(tree, state, &bits);
903 cache_state(state, cached_state);
904 merge_state(tree, state);
905 if (last_end == (u64)-1)
907 start = last_end + 1;
908 state = next_state(state);
909 if (start < end && state && state->start == start &&
916 * | ---- desired range ---- |
919 * | ------------- state -------------- |
921 * We need to split the extent we found, and may flip bits on
924 * If the extent we found extends past our
925 * range, we just split and search again. It'll get split
926 * again the next time though.
928 * If the extent we found is inside our range, we set the
931 if (state->start < start) {
932 if (state->state & exclusive_bits) {
933 *failed_start = start;
938 prealloc = alloc_extent_state_atomic(prealloc);
940 err = split_state(tree, state, prealloc, start);
942 extent_io_tree_panic(tree, err);
947 if (state->end <= end) {
948 set_state_bits(tree, state, &bits);
949 cache_state(state, cached_state);
950 merge_state(tree, state);
951 if (last_end == (u64)-1)
953 start = last_end + 1;
954 state = next_state(state);
955 if (start < end && state && state->start == start &&
962 * | ---- desired range ---- |
963 * | state | or | state |
965 * There's a hole, we need to insert something in it and
966 * ignore the extent we found.
968 if (state->start > start) {
970 if (end < last_start)
973 this_end = last_start - 1;
975 prealloc = alloc_extent_state_atomic(prealloc);
979 * Avoid to free 'prealloc' if it can be merged with
982 err = insert_state(tree, prealloc, start, this_end,
985 extent_io_tree_panic(tree, err);
987 cache_state(prealloc, cached_state);
989 start = this_end + 1;
993 * | ---- desired range ---- |
995 * We need to split the extent, and set the bit
998 if (state->start <= end && state->end > end) {
999 if (state->state & exclusive_bits) {
1000 *failed_start = start;
1005 prealloc = alloc_extent_state_atomic(prealloc);
1007 err = split_state(tree, state, prealloc, end + 1);
1009 extent_io_tree_panic(tree, err);
1011 set_state_bits(tree, prealloc, &bits);
1012 cache_state(prealloc, cached_state);
1013 merge_state(tree, prealloc);
1021 spin_unlock(&tree->lock);
1023 free_extent_state(prealloc);
1030 spin_unlock(&tree->lock);
1031 if (mask & __GFP_WAIT)
1036 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1037 unsigned bits, u64 * failed_start,
1038 struct extent_state **cached_state, gfp_t mask)
1040 return __set_extent_bit(tree, start, end, bits, 0, failed_start,
1041 cached_state, mask);
1046 * convert_extent_bit - convert all bits in a given range from one bit to
1048 * @tree: the io tree to search
1049 * @start: the start offset in bytes
1050 * @end: the end offset in bytes (inclusive)
1051 * @bits: the bits to set in this range
1052 * @clear_bits: the bits to clear in this range
1053 * @cached_state: state that we're going to cache
1054 * @mask: the allocation mask
1056 * This will go through and set bits for the given range. If any states exist
1057 * already in this range they are set with the given bit and cleared of the
1058 * clear_bits. This is only meant to be used by things that are mergeable, ie
1059 * converting from say DELALLOC to DIRTY. This is not meant to be used with
1060 * boundary bits like LOCK.
1062 int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1063 unsigned bits, unsigned clear_bits,
1064 struct extent_state **cached_state, gfp_t mask)
1066 struct extent_state *state;
1067 struct extent_state *prealloc = NULL;
1068 struct rb_node *node;
1070 struct rb_node *parent;
1074 bool first_iteration = true;
1076 btrfs_debug_check_extent_io_range(tree, start, end);
1079 if (!prealloc && (mask & __GFP_WAIT)) {
1081 * Best effort, don't worry if extent state allocation fails
1082 * here for the first iteration. We might have a cached state
1083 * that matches exactly the target range, in which case no
1084 * extent state allocations are needed. We'll only know this
1085 * after locking the tree.
1087 prealloc = alloc_extent_state(mask);
1088 if (!prealloc && !first_iteration)
1092 spin_lock(&tree->lock);
1093 if (cached_state && *cached_state) {
1094 state = *cached_state;
1095 if (state->start <= start && state->end > start &&
1096 extent_state_in_tree(state)) {
1097 node = &state->rb_node;
1103 * this search will find all the extents that end after
1106 node = tree_search_for_insert(tree, start, &p, &parent);
1108 prealloc = alloc_extent_state_atomic(prealloc);
1113 err = insert_state(tree, prealloc, start, end,
1114 &p, &parent, &bits);
1116 extent_io_tree_panic(tree, err);
1117 cache_state(prealloc, cached_state);
1121 state = rb_entry(node, struct extent_state, rb_node);
1123 last_start = state->start;
1124 last_end = state->end;
1127 * | ---- desired range ---- |
1130 * Just lock what we found and keep going
1132 if (state->start == start && state->end <= end) {
1133 set_state_bits(tree, state, &bits);
1134 cache_state(state, cached_state);
1135 state = clear_state_bit(tree, state, &clear_bits, 0);
1136 if (last_end == (u64)-1)
1138 start = last_end + 1;
1139 if (start < end && state && state->start == start &&
1146 * | ---- desired range ---- |
1149 * | ------------- state -------------- |
1151 * We need to split the extent we found, and may flip bits on
1154 * If the extent we found extends past our
1155 * range, we just split and search again. It'll get split
1156 * again the next time though.
1158 * If the extent we found is inside our range, we set the
1159 * desired bit on it.
1161 if (state->start < start) {
1162 prealloc = alloc_extent_state_atomic(prealloc);
1167 err = split_state(tree, state, prealloc, start);
1169 extent_io_tree_panic(tree, err);
1173 if (state->end <= end) {
1174 set_state_bits(tree, state, &bits);
1175 cache_state(state, cached_state);
1176 state = clear_state_bit(tree, state, &clear_bits, 0);
1177 if (last_end == (u64)-1)
1179 start = last_end + 1;
1180 if (start < end && state && state->start == start &&
1187 * | ---- desired range ---- |
1188 * | state | or | state |
1190 * There's a hole, we need to insert something in it and
1191 * ignore the extent we found.
1193 if (state->start > start) {
1195 if (end < last_start)
1198 this_end = last_start - 1;
1200 prealloc = alloc_extent_state_atomic(prealloc);
1207 * Avoid to free 'prealloc' if it can be merged with
1210 err = insert_state(tree, prealloc, start, this_end,
1213 extent_io_tree_panic(tree, err);
1214 cache_state(prealloc, cached_state);
1216 start = this_end + 1;
1220 * | ---- desired range ---- |
1222 * We need to split the extent, and set the bit
1225 if (state->start <= end && state->end > end) {
1226 prealloc = alloc_extent_state_atomic(prealloc);
1232 err = split_state(tree, state, prealloc, end + 1);
1234 extent_io_tree_panic(tree, err);
1236 set_state_bits(tree, prealloc, &bits);
1237 cache_state(prealloc, cached_state);
1238 clear_state_bit(tree, prealloc, &clear_bits, 0);
1246 spin_unlock(&tree->lock);
1248 free_extent_state(prealloc);
1255 spin_unlock(&tree->lock);
1256 if (mask & __GFP_WAIT)
1258 first_iteration = false;
1262 /* wrappers around set/clear extent bit */
1263 int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
1266 return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL,
1270 int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1271 unsigned bits, gfp_t mask)
1273 return set_extent_bit(tree, start, end, bits, NULL,
1277 int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1278 unsigned bits, gfp_t mask)
1282 if (bits & EXTENT_LOCKED)
1285 return clear_extent_bit(tree, start, end, bits, wake, 0, NULL, mask);
1288 int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
1289 struct extent_state **cached_state, gfp_t mask)
1291 return set_extent_bit(tree, start, end,
1292 EXTENT_DELALLOC | EXTENT_UPTODATE,
1293 NULL, cached_state, mask);
1296 int set_extent_defrag(struct extent_io_tree *tree, u64 start, u64 end,
1297 struct extent_state **cached_state, gfp_t mask)
1299 return set_extent_bit(tree, start, end,
1300 EXTENT_DELALLOC | EXTENT_UPTODATE | EXTENT_DEFRAG,
1301 NULL, cached_state, mask);
1304 int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
1307 return clear_extent_bit(tree, start, end,
1308 EXTENT_DIRTY | EXTENT_DELALLOC |
1309 EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
1312 int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
1315 return set_extent_bit(tree, start, end, EXTENT_NEW, NULL,
1319 int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
1320 struct extent_state **cached_state, gfp_t mask)
1322 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, NULL,
1323 cached_state, mask);
1326 int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
1327 struct extent_state **cached_state, gfp_t mask)
1329 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
1330 cached_state, mask);
1334 * either insert or lock state struct between start and end use mask to tell
1335 * us if waiting is desired.
1337 int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1338 unsigned bits, struct extent_state **cached_state)
1344 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
1345 EXTENT_LOCKED, &failed_start,
1346 cached_state, GFP_NOFS);
1347 if (err == -EEXIST) {
1348 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
1349 start = failed_start;
1352 WARN_ON(start > end);
1357 int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1359 return lock_extent_bits(tree, start, end, 0, NULL);
1362 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1367 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1368 &failed_start, NULL, GFP_NOFS);
1369 if (err == -EEXIST) {
1370 if (failed_start > start)
1371 clear_extent_bit(tree, start, failed_start - 1,
1372 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
1378 int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
1379 struct extent_state **cached, gfp_t mask)
1381 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
1385 int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1387 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1391 int extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
1393 unsigned long index = start >> PAGE_CACHE_SHIFT;
1394 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1397 while (index <= end_index) {
1398 page = find_get_page(inode->i_mapping, index);
1399 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1400 clear_page_dirty_for_io(page);
1401 page_cache_release(page);
1407 int extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
1409 unsigned long index = start >> PAGE_CACHE_SHIFT;
1410 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1413 while (index <= end_index) {
1414 page = find_get_page(inode->i_mapping, index);
1415 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1416 __set_page_dirty_nobuffers(page);
1417 account_page_redirty(page);
1418 page_cache_release(page);
1425 * helper function to set both pages and extents in the tree writeback
1427 static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1429 unsigned long index = start >> PAGE_CACHE_SHIFT;
1430 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1433 while (index <= end_index) {
1434 page = find_get_page(tree->mapping, index);
1435 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1436 set_page_writeback(page);
1437 page_cache_release(page);
1443 /* find the first state struct with 'bits' set after 'start', and
1444 * return it. tree->lock must be held. NULL will returned if
1445 * nothing was found after 'start'
1447 static struct extent_state *
1448 find_first_extent_bit_state(struct extent_io_tree *tree,
1449 u64 start, unsigned bits)
1451 struct rb_node *node;
1452 struct extent_state *state;
1455 * this search will find all the extents that end after
1458 node = tree_search(tree, start);
1463 state = rb_entry(node, struct extent_state, rb_node);
1464 if (state->end >= start && (state->state & bits))
1467 node = rb_next(node);
1476 * find the first offset in the io tree with 'bits' set. zero is
1477 * returned if we find something, and *start_ret and *end_ret are
1478 * set to reflect the state struct that was found.
1480 * If nothing was found, 1 is returned. If found something, return 0.
1482 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1483 u64 *start_ret, u64 *end_ret, unsigned bits,
1484 struct extent_state **cached_state)
1486 struct extent_state *state;
1490 spin_lock(&tree->lock);
1491 if (cached_state && *cached_state) {
1492 state = *cached_state;
1493 if (state->end == start - 1 && extent_state_in_tree(state)) {
1494 n = rb_next(&state->rb_node);
1496 state = rb_entry(n, struct extent_state,
1498 if (state->state & bits)
1502 free_extent_state(*cached_state);
1503 *cached_state = NULL;
1506 free_extent_state(*cached_state);
1507 *cached_state = NULL;
1510 state = find_first_extent_bit_state(tree, start, bits);
1513 cache_state_if_flags(state, cached_state, 0);
1514 *start_ret = state->start;
1515 *end_ret = state->end;
1519 spin_unlock(&tree->lock);
1524 * find a contiguous range of bytes in the file marked as delalloc, not
1525 * more than 'max_bytes'. start and end are used to return the range,
1527 * 1 is returned if we find something, 0 if nothing was in the tree
1529 static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1530 u64 *start, u64 *end, u64 max_bytes,
1531 struct extent_state **cached_state)
1533 struct rb_node *node;
1534 struct extent_state *state;
1535 u64 cur_start = *start;
1537 u64 total_bytes = 0;
1539 spin_lock(&tree->lock);
1542 * this search will find all the extents that end after
1545 node = tree_search(tree, cur_start);
1553 state = rb_entry(node, struct extent_state, rb_node);
1554 if (found && (state->start != cur_start ||
1555 (state->state & EXTENT_BOUNDARY))) {
1558 if (!(state->state & EXTENT_DELALLOC)) {
1564 *start = state->start;
1565 *cached_state = state;
1566 atomic_inc(&state->refs);
1570 cur_start = state->end + 1;
1571 node = rb_next(node);
1572 total_bytes += state->end - state->start + 1;
1573 if (total_bytes >= max_bytes)
1579 spin_unlock(&tree->lock);
1583 static noinline void __unlock_for_delalloc(struct inode *inode,
1584 struct page *locked_page,
1588 struct page *pages[16];
1589 unsigned long index = start >> PAGE_CACHE_SHIFT;
1590 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1591 unsigned long nr_pages = end_index - index + 1;
1594 if (index == locked_page->index && end_index == index)
1597 while (nr_pages > 0) {
1598 ret = find_get_pages_contig(inode->i_mapping, index,
1599 min_t(unsigned long, nr_pages,
1600 ARRAY_SIZE(pages)), pages);
1601 for (i = 0; i < ret; i++) {
1602 if (pages[i] != locked_page)
1603 unlock_page(pages[i]);
1604 page_cache_release(pages[i]);
1612 static noinline int lock_delalloc_pages(struct inode *inode,
1613 struct page *locked_page,
1617 unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
1618 unsigned long start_index = index;
1619 unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
1620 unsigned long pages_locked = 0;
1621 struct page *pages[16];
1622 unsigned long nrpages;
1626 /* the caller is responsible for locking the start index */
1627 if (index == locked_page->index && index == end_index)
1630 /* skip the page at the start index */
1631 nrpages = end_index - index + 1;
1632 while (nrpages > 0) {
1633 ret = find_get_pages_contig(inode->i_mapping, index,
1634 min_t(unsigned long,
1635 nrpages, ARRAY_SIZE(pages)), pages);
1640 /* now we have an array of pages, lock them all */
1641 for (i = 0; i < ret; i++) {
1643 * the caller is taking responsibility for
1646 if (pages[i] != locked_page) {
1647 lock_page(pages[i]);
1648 if (!PageDirty(pages[i]) ||
1649 pages[i]->mapping != inode->i_mapping) {
1651 unlock_page(pages[i]);
1652 page_cache_release(pages[i]);
1656 page_cache_release(pages[i]);
1665 if (ret && pages_locked) {
1666 __unlock_for_delalloc(inode, locked_page,
1668 ((u64)(start_index + pages_locked - 1)) <<
1675 * find a contiguous range of bytes in the file marked as delalloc, not
1676 * more than 'max_bytes'. start and end are used to return the range,
1678 * 1 is returned if we find something, 0 if nothing was in the tree
1680 STATIC u64 find_lock_delalloc_range(struct inode *inode,
1681 struct extent_io_tree *tree,
1682 struct page *locked_page, u64 *start,
1683 u64 *end, u64 max_bytes)
1688 struct extent_state *cached_state = NULL;
1693 /* step one, find a bunch of delalloc bytes starting at start */
1694 delalloc_start = *start;
1696 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1697 max_bytes, &cached_state);
1698 if (!found || delalloc_end <= *start) {
1699 *start = delalloc_start;
1700 *end = delalloc_end;
1701 free_extent_state(cached_state);
1706 * start comes from the offset of locked_page. We have to lock
1707 * pages in order, so we can't process delalloc bytes before
1710 if (delalloc_start < *start)
1711 delalloc_start = *start;
1714 * make sure to limit the number of pages we try to lock down
1716 if (delalloc_end + 1 - delalloc_start > max_bytes)
1717 delalloc_end = delalloc_start + max_bytes - 1;
1719 /* step two, lock all the pages after the page that has start */
1720 ret = lock_delalloc_pages(inode, locked_page,
1721 delalloc_start, delalloc_end);
1722 if (ret == -EAGAIN) {
1723 /* some of the pages are gone, lets avoid looping by
1724 * shortening the size of the delalloc range we're searching
1726 free_extent_state(cached_state);
1727 cached_state = NULL;
1729 max_bytes = PAGE_CACHE_SIZE;
1737 BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
1739 /* step three, lock the state bits for the whole range */
1740 lock_extent_bits(tree, delalloc_start, delalloc_end, 0, &cached_state);
1742 /* then test to make sure it is all still delalloc */
1743 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1744 EXTENT_DELALLOC, 1, cached_state);
1746 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1747 &cached_state, GFP_NOFS);
1748 __unlock_for_delalloc(inode, locked_page,
1749 delalloc_start, delalloc_end);
1753 free_extent_state(cached_state);
1754 *start = delalloc_start;
1755 *end = delalloc_end;
1760 int extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
1761 struct page *locked_page,
1762 unsigned clear_bits,
1763 unsigned long page_ops)
1765 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
1767 struct page *pages[16];
1768 unsigned long index = start >> PAGE_CACHE_SHIFT;
1769 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1770 unsigned long nr_pages = end_index - index + 1;
1773 clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1777 if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
1778 mapping_set_error(inode->i_mapping, -EIO);
1780 while (nr_pages > 0) {
1781 ret = find_get_pages_contig(inode->i_mapping, index,
1782 min_t(unsigned long,
1783 nr_pages, ARRAY_SIZE(pages)), pages);
1784 for (i = 0; i < ret; i++) {
1786 if (page_ops & PAGE_SET_PRIVATE2)
1787 SetPagePrivate2(pages[i]);
1789 if (pages[i] == locked_page) {
1790 page_cache_release(pages[i]);
1793 if (page_ops & PAGE_CLEAR_DIRTY)
1794 clear_page_dirty_for_io(pages[i]);
1795 if (page_ops & PAGE_SET_WRITEBACK)
1796 set_page_writeback(pages[i]);
1797 if (page_ops & PAGE_SET_ERROR)
1798 SetPageError(pages[i]);
1799 if (page_ops & PAGE_END_WRITEBACK)
1800 end_page_writeback(pages[i]);
1801 if (page_ops & PAGE_UNLOCK)
1802 unlock_page(pages[i]);
1803 page_cache_release(pages[i]);
1813 * count the number of bytes in the tree that have a given bit(s)
1814 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1815 * cached. The total number found is returned.
1817 u64 count_range_bits(struct extent_io_tree *tree,
1818 u64 *start, u64 search_end, u64 max_bytes,
1819 unsigned bits, int contig)
1821 struct rb_node *node;
1822 struct extent_state *state;
1823 u64 cur_start = *start;
1824 u64 total_bytes = 0;
1828 if (WARN_ON(search_end <= cur_start))
1831 spin_lock(&tree->lock);
1832 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1833 total_bytes = tree->dirty_bytes;
1837 * this search will find all the extents that end after
1840 node = tree_search(tree, cur_start);
1845 state = rb_entry(node, struct extent_state, rb_node);
1846 if (state->start > search_end)
1848 if (contig && found && state->start > last + 1)
1850 if (state->end >= cur_start && (state->state & bits) == bits) {
1851 total_bytes += min(search_end, state->end) + 1 -
1852 max(cur_start, state->start);
1853 if (total_bytes >= max_bytes)
1856 *start = max(cur_start, state->start);
1860 } else if (contig && found) {
1863 node = rb_next(node);
1868 spin_unlock(&tree->lock);
1873 * set the private field for a given byte offset in the tree. If there isn't
1874 * an extent_state there already, this does nothing.
1876 static int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1878 struct rb_node *node;
1879 struct extent_state *state;
1882 spin_lock(&tree->lock);
1884 * this search will find all the extents that end after
1887 node = tree_search(tree, start);
1892 state = rb_entry(node, struct extent_state, rb_node);
1893 if (state->start != start) {
1897 state->private = private;
1899 spin_unlock(&tree->lock);
1903 int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1905 struct rb_node *node;
1906 struct extent_state *state;
1909 spin_lock(&tree->lock);
1911 * this search will find all the extents that end after
1914 node = tree_search(tree, start);
1919 state = rb_entry(node, struct extent_state, rb_node);
1920 if (state->start != start) {
1924 *private = state->private;
1926 spin_unlock(&tree->lock);
1931 * searches a range in the state tree for a given mask.
1932 * If 'filled' == 1, this returns 1 only if every extent in the tree
1933 * has the bits set. Otherwise, 1 is returned if any bit in the
1934 * range is found set.
1936 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1937 unsigned bits, int filled, struct extent_state *cached)
1939 struct extent_state *state = NULL;
1940 struct rb_node *node;
1943 spin_lock(&tree->lock);
1944 if (cached && extent_state_in_tree(cached) && cached->start <= start &&
1945 cached->end > start)
1946 node = &cached->rb_node;
1948 node = tree_search(tree, start);
1949 while (node && start <= end) {
1950 state = rb_entry(node, struct extent_state, rb_node);
1952 if (filled && state->start > start) {
1957 if (state->start > end)
1960 if (state->state & bits) {
1964 } else if (filled) {
1969 if (state->end == (u64)-1)
1972 start = state->end + 1;
1975 node = rb_next(node);
1982 spin_unlock(&tree->lock);
1987 * helper function to set a given page up to date if all the
1988 * extents in the tree for that page are up to date
1990 static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1992 u64 start = page_offset(page);
1993 u64 end = start + PAGE_CACHE_SIZE - 1;
1994 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1995 SetPageUptodate(page);
1998 int free_io_failure(struct inode *inode, struct io_failure_record *rec)
2002 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2004 set_state_private(failure_tree, rec->start, 0);
2005 ret = clear_extent_bits(failure_tree, rec->start,
2006 rec->start + rec->len - 1,
2007 EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
2011 ret = clear_extent_bits(&BTRFS_I(inode)->io_tree, rec->start,
2012 rec->start + rec->len - 1,
2013 EXTENT_DAMAGED, GFP_NOFS);
2022 * this bypasses the standard btrfs submit functions deliberately, as
2023 * the standard behavior is to write all copies in a raid setup. here we only
2024 * want to write the one bad copy. so we do the mapping for ourselves and issue
2025 * submit_bio directly.
2026 * to avoid any synchronization issues, wait for the data after writing, which
2027 * actually prevents the read that triggered the error from finishing.
2028 * currently, there can be no more than two copies of every data bit. thus,
2029 * exactly one rewrite is required.
2031 int repair_io_failure(struct inode *inode, u64 start, u64 length, u64 logical,
2032 struct page *page, unsigned int pg_offset, int mirror_num)
2034 struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2036 struct btrfs_device *dev;
2039 struct btrfs_bio *bbio = NULL;
2040 struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
2043 ASSERT(!(fs_info->sb->s_flags & MS_RDONLY));
2044 BUG_ON(!mirror_num);
2046 /* we can't repair anything in raid56 yet */
2047 if (btrfs_is_parity_mirror(map_tree, logical, length, mirror_num))
2050 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2053 bio->bi_iter.bi_size = 0;
2054 map_length = length;
2056 ret = btrfs_map_block(fs_info, WRITE, logical,
2057 &map_length, &bbio, mirror_num);
2062 BUG_ON(mirror_num != bbio->mirror_num);
2063 sector = bbio->stripes[mirror_num-1].physical >> 9;
2064 bio->bi_iter.bi_sector = sector;
2065 dev = bbio->stripes[mirror_num-1].dev;
2066 btrfs_put_bbio(bbio);
2067 if (!dev || !dev->bdev || !dev->writeable) {
2071 bio->bi_bdev = dev->bdev;
2072 bio_add_page(bio, page, length, pg_offset);
2074 if (btrfsic_submit_bio_wait(WRITE_SYNC, bio)) {
2075 /* try to remap that extent elsewhere? */
2077 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2081 printk_ratelimited_in_rcu(KERN_INFO
2082 "BTRFS: read error corrected: ino %llu off %llu (dev %s sector %llu)\n",
2083 btrfs_ino(inode), start,
2084 rcu_str_deref(dev->name), sector);
2089 int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb,
2092 u64 start = eb->start;
2093 unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
2096 if (root->fs_info->sb->s_flags & MS_RDONLY)
2099 for (i = 0; i < num_pages; i++) {
2100 struct page *p = eb->pages[i];
2102 ret = repair_io_failure(root->fs_info->btree_inode, start,
2103 PAGE_CACHE_SIZE, start, p,
2104 start - page_offset(p), mirror_num);
2107 start += PAGE_CACHE_SIZE;
2114 * each time an IO finishes, we do a fast check in the IO failure tree
2115 * to see if we need to process or clean up an io_failure_record
2117 int clean_io_failure(struct inode *inode, u64 start, struct page *page,
2118 unsigned int pg_offset)
2121 u64 private_failure;
2122 struct io_failure_record *failrec;
2123 struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2124 struct extent_state *state;
2129 ret = count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
2130 (u64)-1, 1, EXTENT_DIRTY, 0);
2134 ret = get_state_private(&BTRFS_I(inode)->io_failure_tree, start,
2139 failrec = (struct io_failure_record *)(unsigned long) private_failure;
2140 BUG_ON(!failrec->this_mirror);
2142 if (failrec->in_validation) {
2143 /* there was no real error, just free the record */
2144 pr_debug("clean_io_failure: freeing dummy error at %llu\n",
2148 if (fs_info->sb->s_flags & MS_RDONLY)
2151 spin_lock(&BTRFS_I(inode)->io_tree.lock);
2152 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
2155 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
2157 if (state && state->start <= failrec->start &&
2158 state->end >= failrec->start + failrec->len - 1) {
2159 num_copies = btrfs_num_copies(fs_info, failrec->logical,
2161 if (num_copies > 1) {
2162 repair_io_failure(inode, start, failrec->len,
2163 failrec->logical, page,
2164 pg_offset, failrec->failed_mirror);
2169 free_io_failure(inode, failrec);
2175 * Can be called when
2176 * - hold extent lock
2177 * - under ordered extent
2178 * - the inode is freeing
2180 void btrfs_free_io_failure_record(struct inode *inode, u64 start, u64 end)
2182 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2183 struct io_failure_record *failrec;
2184 struct extent_state *state, *next;
2186 if (RB_EMPTY_ROOT(&failure_tree->state))
2189 spin_lock(&failure_tree->lock);
2190 state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
2192 if (state->start > end)
2195 ASSERT(state->end <= end);
2197 next = next_state(state);
2199 failrec = (struct io_failure_record *)(unsigned long)state->private;
2200 free_extent_state(state);
2205 spin_unlock(&failure_tree->lock);
2208 int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
2209 struct io_failure_record **failrec_ret)
2211 struct io_failure_record *failrec;
2213 struct extent_map *em;
2214 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2215 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2216 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2220 ret = get_state_private(failure_tree, start, &private);
2222 failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
2226 failrec->start = start;
2227 failrec->len = end - start + 1;
2228 failrec->this_mirror = 0;
2229 failrec->bio_flags = 0;
2230 failrec->in_validation = 0;
2232 read_lock(&em_tree->lock);
2233 em = lookup_extent_mapping(em_tree, start, failrec->len);
2235 read_unlock(&em_tree->lock);
2240 if (em->start > start || em->start + em->len <= start) {
2241 free_extent_map(em);
2244 read_unlock(&em_tree->lock);
2250 logical = start - em->start;
2251 logical = em->block_start + logical;
2252 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2253 logical = em->block_start;
2254 failrec->bio_flags = EXTENT_BIO_COMPRESSED;
2255 extent_set_compress_type(&failrec->bio_flags,
2259 pr_debug("Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu\n",
2260 logical, start, failrec->len);
2262 failrec->logical = logical;
2263 free_extent_map(em);
2265 /* set the bits in the private failure tree */
2266 ret = set_extent_bits(failure_tree, start, end,
2267 EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
2269 ret = set_state_private(failure_tree, start,
2270 (u64)(unsigned long)failrec);
2271 /* set the bits in the inode's tree */
2273 ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED,
2280 failrec = (struct io_failure_record *)(unsigned long)private;
2281 pr_debug("Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d\n",
2282 failrec->logical, failrec->start, failrec->len,
2283 failrec->in_validation);
2285 * when data can be on disk more than twice, add to failrec here
2286 * (e.g. with a list for failed_mirror) to make
2287 * clean_io_failure() clean all those errors at once.
2291 *failrec_ret = failrec;
2296 int btrfs_check_repairable(struct inode *inode, struct bio *failed_bio,
2297 struct io_failure_record *failrec, int failed_mirror)
2301 num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
2302 failrec->logical, failrec->len);
2303 if (num_copies == 1) {
2305 * we only have a single copy of the data, so don't bother with
2306 * all the retry and error correction code that follows. no
2307 * matter what the error is, it is very likely to persist.
2309 pr_debug("Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
2310 num_copies, failrec->this_mirror, failed_mirror);
2315 * there are two premises:
2316 * a) deliver good data to the caller
2317 * b) correct the bad sectors on disk
2319 if (failed_bio->bi_vcnt > 1) {
2321 * to fulfill b), we need to know the exact failing sectors, as
2322 * we don't want to rewrite any more than the failed ones. thus,
2323 * we need separate read requests for the failed bio
2325 * if the following BUG_ON triggers, our validation request got
2326 * merged. we need separate requests for our algorithm to work.
2328 BUG_ON(failrec->in_validation);
2329 failrec->in_validation = 1;
2330 failrec->this_mirror = failed_mirror;
2333 * we're ready to fulfill a) and b) alongside. get a good copy
2334 * of the failed sector and if we succeed, we have setup
2335 * everything for repair_io_failure to do the rest for us.
2337 if (failrec->in_validation) {
2338 BUG_ON(failrec->this_mirror != failed_mirror);
2339 failrec->in_validation = 0;
2340 failrec->this_mirror = 0;
2342 failrec->failed_mirror = failed_mirror;
2343 failrec->this_mirror++;
2344 if (failrec->this_mirror == failed_mirror)
2345 failrec->this_mirror++;
2348 if (failrec->this_mirror > num_copies) {
2349 pr_debug("Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
2350 num_copies, failrec->this_mirror, failed_mirror);
2358 struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
2359 struct io_failure_record *failrec,
2360 struct page *page, int pg_offset, int icsum,
2361 bio_end_io_t *endio_func, void *data)
2364 struct btrfs_io_bio *btrfs_failed_bio;
2365 struct btrfs_io_bio *btrfs_bio;
2367 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2371 bio->bi_end_io = endio_func;
2372 bio->bi_iter.bi_sector = failrec->logical >> 9;
2373 bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
2374 bio->bi_iter.bi_size = 0;
2375 bio->bi_private = data;
2377 btrfs_failed_bio = btrfs_io_bio(failed_bio);
2378 if (btrfs_failed_bio->csum) {
2379 struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2380 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
2382 btrfs_bio = btrfs_io_bio(bio);
2383 btrfs_bio->csum = btrfs_bio->csum_inline;
2385 memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
2389 bio_add_page(bio, page, failrec->len, pg_offset);
2395 * this is a generic handler for readpage errors (default
2396 * readpage_io_failed_hook). if other copies exist, read those and write back
2397 * good data to the failed position. does not investigate in remapping the
2398 * failed extent elsewhere, hoping the device will be smart enough to do this as
2402 static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
2403 struct page *page, u64 start, u64 end,
2406 struct io_failure_record *failrec;
2407 struct inode *inode = page->mapping->host;
2408 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2413 BUG_ON(failed_bio->bi_rw & REQ_WRITE);
2415 ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
2419 ret = btrfs_check_repairable(inode, failed_bio, failrec, failed_mirror);
2421 free_io_failure(inode, failrec);
2425 if (failed_bio->bi_vcnt > 1)
2426 read_mode = READ_SYNC | REQ_FAILFAST_DEV;
2428 read_mode = READ_SYNC;
2430 phy_offset >>= inode->i_sb->s_blocksize_bits;
2431 bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
2432 start - page_offset(page),
2433 (int)phy_offset, failed_bio->bi_end_io,
2436 free_io_failure(inode, failrec);
2440 pr_debug("Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d\n",
2441 read_mode, failrec->this_mirror, failrec->in_validation);
2443 ret = tree->ops->submit_bio_hook(inode, read_mode, bio,
2444 failrec->this_mirror,
2445 failrec->bio_flags, 0);
2447 free_io_failure(inode, failrec);
2454 /* lots and lots of room for performance fixes in the end_bio funcs */
2456 int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
2458 int uptodate = (err == 0);
2459 struct extent_io_tree *tree;
2462 tree = &BTRFS_I(page->mapping->host)->io_tree;
2464 if (tree->ops && tree->ops->writepage_end_io_hook) {
2465 ret = tree->ops->writepage_end_io_hook(page, start,
2466 end, NULL, uptodate);
2472 ClearPageUptodate(page);
2474 ret = ret < 0 ? ret : -EIO;
2475 mapping_set_error(page->mapping, ret);
2481 * after a writepage IO is done, we need to:
2482 * clear the uptodate bits on error
2483 * clear the writeback bits in the extent tree for this IO
2484 * end_page_writeback if the page has no more pending IO
2486 * Scheduling is not allowed, so the extent state tree is expected
2487 * to have one and only one object corresponding to this IO.
2489 static void end_bio_extent_writepage(struct bio *bio, int err)
2491 struct bio_vec *bvec;
2496 bio_for_each_segment_all(bvec, bio, i) {
2497 struct page *page = bvec->bv_page;
2499 /* We always issue full-page reads, but if some block
2500 * in a page fails to read, blk_update_request() will
2501 * advance bv_offset and adjust bv_len to compensate.
2502 * Print a warning for nonzero offsets, and an error
2503 * if they don't add up to a full page. */
2504 if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE) {
2505 if (bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE)
2506 btrfs_err(BTRFS_I(page->mapping->host)->root->fs_info,
2507 "partial page write in btrfs with offset %u and length %u",
2508 bvec->bv_offset, bvec->bv_len);
2510 btrfs_info(BTRFS_I(page->mapping->host)->root->fs_info,
2511 "incomplete page write in btrfs with offset %u and "
2513 bvec->bv_offset, bvec->bv_len);
2516 start = page_offset(page);
2517 end = start + bvec->bv_offset + bvec->bv_len - 1;
2519 if (end_extent_writepage(page, err, start, end))
2522 end_page_writeback(page);
2529 endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
2532 struct extent_state *cached = NULL;
2533 u64 end = start + len - 1;
2535 if (uptodate && tree->track_uptodate)
2536 set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
2537 unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
2541 * after a readpage IO is done, we need to:
2542 * clear the uptodate bits on error
2543 * set the uptodate bits if things worked
2544 * set the page up to date if all extents in the tree are uptodate
2545 * clear the lock bit in the extent tree
2546 * unlock the page if there are no other extents locked for it
2548 * Scheduling is not allowed, so the extent state tree is expected
2549 * to have one and only one object corresponding to this IO.
2551 static void end_bio_extent_readpage(struct bio *bio, int err)
2553 struct bio_vec *bvec;
2554 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
2555 struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2556 struct extent_io_tree *tree;
2561 u64 extent_start = 0;
2570 bio_for_each_segment_all(bvec, bio, i) {
2571 struct page *page = bvec->bv_page;
2572 struct inode *inode = page->mapping->host;
2574 pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
2575 "mirror=%u\n", (u64)bio->bi_iter.bi_sector, err,
2576 io_bio->mirror_num);
2577 tree = &BTRFS_I(inode)->io_tree;
2579 /* We always issue full-page reads, but if some block
2580 * in a page fails to read, blk_update_request() will
2581 * advance bv_offset and adjust bv_len to compensate.
2582 * Print a warning for nonzero offsets, and an error
2583 * if they don't add up to a full page. */
2584 if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE) {
2585 if (bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE)
2586 btrfs_err(BTRFS_I(page->mapping->host)->root->fs_info,
2587 "partial page read in btrfs with offset %u and length %u",
2588 bvec->bv_offset, bvec->bv_len);
2590 btrfs_info(BTRFS_I(page->mapping->host)->root->fs_info,
2591 "incomplete page read in btrfs with offset %u and "
2593 bvec->bv_offset, bvec->bv_len);
2596 start = page_offset(page);
2597 end = start + bvec->bv_offset + bvec->bv_len - 1;
2600 mirror = io_bio->mirror_num;
2601 if (likely(uptodate && tree->ops &&
2602 tree->ops->readpage_end_io_hook)) {
2603 ret = tree->ops->readpage_end_io_hook(io_bio, offset,
2609 clean_io_failure(inode, start, page, 0);
2612 if (likely(uptodate))
2615 if (tree->ops && tree->ops->readpage_io_failed_hook) {
2616 ret = tree->ops->readpage_io_failed_hook(page, mirror);
2618 test_bit(BIO_UPTODATE, &bio->bi_flags))
2622 * The generic bio_readpage_error handles errors the
2623 * following way: If possible, new read requests are
2624 * created and submitted and will end up in
2625 * end_bio_extent_readpage as well (if we're lucky, not
2626 * in the !uptodate case). In that case it returns 0 and
2627 * we just go on with the next page in our bio. If it
2628 * can't handle the error it will return -EIO and we
2629 * remain responsible for that page.
2631 ret = bio_readpage_error(bio, offset, page, start, end,
2635 test_bit(BIO_UPTODATE, &bio->bi_flags);
2643 if (likely(uptodate)) {
2644 loff_t i_size = i_size_read(inode);
2645 pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
2648 /* Zero out the end if this page straddles i_size */
2649 off = i_size & (PAGE_CACHE_SIZE-1);
2650 if (page->index == end_index && off)
2651 zero_user_segment(page, off, PAGE_CACHE_SIZE);
2652 SetPageUptodate(page);
2654 ClearPageUptodate(page);
2660 if (unlikely(!uptodate)) {
2662 endio_readpage_release_extent(tree,
2668 endio_readpage_release_extent(tree, start,
2669 end - start + 1, 0);
2670 } else if (!extent_len) {
2671 extent_start = start;
2672 extent_len = end + 1 - start;
2673 } else if (extent_start + extent_len == start) {
2674 extent_len += end + 1 - start;
2676 endio_readpage_release_extent(tree, extent_start,
2677 extent_len, uptodate);
2678 extent_start = start;
2679 extent_len = end + 1 - start;
2684 endio_readpage_release_extent(tree, extent_start, extent_len,
2687 io_bio->end_io(io_bio, err);
2692 * this allocates from the btrfs_bioset. We're returning a bio right now
2693 * but you can call btrfs_io_bio for the appropriate container_of magic
2696 btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
2699 struct btrfs_io_bio *btrfs_bio;
2702 bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
2704 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2705 while (!bio && (nr_vecs /= 2)) {
2706 bio = bio_alloc_bioset(gfp_flags,
2707 nr_vecs, btrfs_bioset);
2712 bio->bi_bdev = bdev;
2713 bio->bi_iter.bi_sector = first_sector;
2714 btrfs_bio = btrfs_io_bio(bio);
2715 btrfs_bio->csum = NULL;
2716 btrfs_bio->csum_allocated = NULL;
2717 btrfs_bio->end_io = NULL;
2722 struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
2724 struct btrfs_io_bio *btrfs_bio;
2727 new = bio_clone_bioset(bio, gfp_mask, btrfs_bioset);
2729 btrfs_bio = btrfs_io_bio(new);
2730 btrfs_bio->csum = NULL;
2731 btrfs_bio->csum_allocated = NULL;
2732 btrfs_bio->end_io = NULL;
2734 #ifdef CONFIG_BLK_CGROUP
2735 /* FIXME, put this into bio_clone_bioset */
2737 bio_associate_blkcg(new, bio->bi_css);
2743 /* this also allocates from the btrfs_bioset */
2744 struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
2746 struct btrfs_io_bio *btrfs_bio;
2749 bio = bio_alloc_bioset(gfp_mask, nr_iovecs, btrfs_bioset);
2751 btrfs_bio = btrfs_io_bio(bio);
2752 btrfs_bio->csum = NULL;
2753 btrfs_bio->csum_allocated = NULL;
2754 btrfs_bio->end_io = NULL;
2760 static int __must_check submit_one_bio(int rw, struct bio *bio,
2761 int mirror_num, unsigned long bio_flags)
2764 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
2765 struct page *page = bvec->bv_page;
2766 struct extent_io_tree *tree = bio->bi_private;
2769 start = page_offset(page) + bvec->bv_offset;
2771 bio->bi_private = NULL;
2775 if (tree->ops && tree->ops->submit_bio_hook)
2776 ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
2777 mirror_num, bio_flags, start);
2779 btrfsic_submit_bio(rw, bio);
2785 static int merge_bio(int rw, struct extent_io_tree *tree, struct page *page,
2786 unsigned long offset, size_t size, struct bio *bio,
2787 unsigned long bio_flags)
2790 if (tree->ops && tree->ops->merge_bio_hook)
2791 ret = tree->ops->merge_bio_hook(rw, page, offset, size, bio,
2798 static int submit_extent_page(int rw, struct extent_io_tree *tree,
2799 struct writeback_control *wbc,
2800 struct page *page, sector_t sector,
2801 size_t size, unsigned long offset,
2802 struct block_device *bdev,
2803 struct bio **bio_ret,
2804 unsigned long max_pages,
2805 bio_end_io_t end_io_func,
2807 unsigned long prev_bio_flags,
2808 unsigned long bio_flags,
2809 bool force_bio_submit)
2815 int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
2816 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2817 size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
2819 if (bio_ret && *bio_ret) {
2822 contig = bio->bi_iter.bi_sector == sector;
2824 contig = bio_end_sector(bio) == sector;
2826 if (prev_bio_flags != bio_flags || !contig ||
2828 merge_bio(rw, tree, page, offset, page_size, bio, bio_flags) ||
2829 bio_add_page(bio, page, page_size, offset) < page_size) {
2830 ret = submit_one_bio(rw, bio, mirror_num,
2839 wbc_account_io(wbc, page, page_size);
2843 if (this_compressed)
2846 nr = bio_get_nr_vecs(bdev);
2848 bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
2852 bio_add_page(bio, page, page_size, offset);
2853 bio->bi_end_io = end_io_func;
2854 bio->bi_private = tree;
2856 wbc_init_bio(wbc, bio);
2857 wbc_account_io(wbc, page, page_size);
2863 ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
2868 static void attach_extent_buffer_page(struct extent_buffer *eb,
2871 if (!PagePrivate(page)) {
2872 SetPagePrivate(page);
2873 page_cache_get(page);
2874 set_page_private(page, (unsigned long)eb);
2876 WARN_ON(page->private != (unsigned long)eb);
2880 void set_page_extent_mapped(struct page *page)
2882 if (!PagePrivate(page)) {
2883 SetPagePrivate(page);
2884 page_cache_get(page);
2885 set_page_private(page, EXTENT_PAGE_PRIVATE);
2889 static struct extent_map *
2890 __get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
2891 u64 start, u64 len, get_extent_t *get_extent,
2892 struct extent_map **em_cached)
2894 struct extent_map *em;
2896 if (em_cached && *em_cached) {
2898 if (extent_map_in_tree(em) && start >= em->start &&
2899 start < extent_map_end(em)) {
2900 atomic_inc(&em->refs);
2904 free_extent_map(em);
2908 em = get_extent(inode, page, pg_offset, start, len, 0);
2909 if (em_cached && !IS_ERR_OR_NULL(em)) {
2911 atomic_inc(&em->refs);
2917 * basic readpage implementation. Locked extent state structs are inserted
2918 * into the tree that are removed when the IO is done (by the end_io
2920 * XXX JDM: This needs looking at to ensure proper page locking
2922 static int __do_readpage(struct extent_io_tree *tree,
2924 get_extent_t *get_extent,
2925 struct extent_map **em_cached,
2926 struct bio **bio, int mirror_num,
2927 unsigned long *bio_flags, int rw,
2930 struct inode *inode = page->mapping->host;
2931 u64 start = page_offset(page);
2932 u64 page_end = start + PAGE_CACHE_SIZE - 1;
2936 u64 last_byte = i_size_read(inode);
2940 struct extent_map *em;
2941 struct block_device *bdev;
2944 int parent_locked = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2945 size_t pg_offset = 0;
2947 size_t disk_io_size;
2948 size_t blocksize = inode->i_sb->s_blocksize;
2949 unsigned long this_bio_flag = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2951 set_page_extent_mapped(page);
2954 if (!PageUptodate(page)) {
2955 if (cleancache_get_page(page) == 0) {
2956 BUG_ON(blocksize != PAGE_SIZE);
2957 unlock_extent(tree, start, end);
2962 if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
2964 size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
2967 iosize = PAGE_CACHE_SIZE - zero_offset;
2968 userpage = kmap_atomic(page);
2969 memset(userpage + zero_offset, 0, iosize);
2970 flush_dcache_page(page);
2971 kunmap_atomic(userpage);
2974 while (cur <= end) {
2975 unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
2976 bool force_bio_submit = false;
2978 if (cur >= last_byte) {
2980 struct extent_state *cached = NULL;
2982 iosize = PAGE_CACHE_SIZE - pg_offset;
2983 userpage = kmap_atomic(page);
2984 memset(userpage + pg_offset, 0, iosize);
2985 flush_dcache_page(page);
2986 kunmap_atomic(userpage);
2987 set_extent_uptodate(tree, cur, cur + iosize - 1,
2990 unlock_extent_cached(tree, cur,
2995 em = __get_extent_map(inode, page, pg_offset, cur,
2996 end - cur + 1, get_extent, em_cached);
2997 if (IS_ERR_OR_NULL(em)) {
3000 unlock_extent(tree, cur, end);
3003 extent_offset = cur - em->start;
3004 BUG_ON(extent_map_end(em) <= cur);
3007 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
3008 this_bio_flag |= EXTENT_BIO_COMPRESSED;
3009 extent_set_compress_type(&this_bio_flag,
3013 iosize = min(extent_map_end(em) - cur, end - cur + 1);
3014 cur_end = min(extent_map_end(em) - 1, end);
3015 iosize = ALIGN(iosize, blocksize);
3016 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
3017 disk_io_size = em->block_len;
3018 sector = em->block_start >> 9;
3020 sector = (em->block_start + extent_offset) >> 9;
3021 disk_io_size = iosize;
3024 block_start = em->block_start;
3025 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
3026 block_start = EXTENT_MAP_HOLE;
3029 * If we have a file range that points to a compressed extent
3030 * and it's followed by a consecutive file range that points to
3031 * to the same compressed extent (possibly with a different
3032 * offset and/or length, so it either points to the whole extent
3033 * or only part of it), we must make sure we do not submit a
3034 * single bio to populate the pages for the 2 ranges because
3035 * this makes the compressed extent read zero out the pages
3036 * belonging to the 2nd range. Imagine the following scenario:
3039 * [0 - 8K] [8K - 24K]
3042 * points to extent X, points to extent X,
3043 * offset 4K, length of 8K offset 0, length 16K
3045 * [extent X, compressed length = 4K uncompressed length = 16K]
3047 * If the bio to read the compressed extent covers both ranges,
3048 * it will decompress extent X into the pages belonging to the
3049 * first range and then it will stop, zeroing out the remaining
3050 * pages that belong to the other range that points to extent X.
3051 * So here we make sure we submit 2 bios, one for the first
3052 * range and another one for the third range. Both will target
3053 * the same physical extent from disk, but we can't currently
3054 * make the compressed bio endio callback populate the pages
3055 * for both ranges because each compressed bio is tightly
3056 * coupled with a single extent map, and each range can have
3057 * an extent map with a different offset value relative to the
3058 * uncompressed data of our extent and different lengths. This
3059 * is a corner case so we prioritize correctness over
3060 * non-optimal behavior (submitting 2 bios for the same extent).
3062 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
3063 prev_em_start && *prev_em_start != (u64)-1 &&
3064 *prev_em_start != em->orig_start)
3065 force_bio_submit = true;
3068 *prev_em_start = em->orig_start;
3070 free_extent_map(em);
3073 /* we've found a hole, just zero and go on */
3074 if (block_start == EXTENT_MAP_HOLE) {
3076 struct extent_state *cached = NULL;
3078 userpage = kmap_atomic(page);
3079 memset(userpage + pg_offset, 0, iosize);
3080 flush_dcache_page(page);
3081 kunmap_atomic(userpage);
3083 set_extent_uptodate(tree, cur, cur + iosize - 1,
3085 unlock_extent_cached(tree, cur, cur + iosize - 1,
3088 pg_offset += iosize;
3091 /* the get_extent function already copied into the page */
3092 if (test_range_bit(tree, cur, cur_end,
3093 EXTENT_UPTODATE, 1, NULL)) {
3094 check_page_uptodate(tree, page);
3096 unlock_extent(tree, cur, cur + iosize - 1);
3098 pg_offset += iosize;
3101 /* we have an inline extent but it didn't get marked up
3102 * to date. Error out
3104 if (block_start == EXTENT_MAP_INLINE) {
3107 unlock_extent(tree, cur, cur + iosize - 1);
3109 pg_offset += iosize;
3114 ret = submit_extent_page(rw, tree, NULL, page,
3115 sector, disk_io_size, pg_offset,
3117 end_bio_extent_readpage, mirror_num,
3123 *bio_flags = this_bio_flag;
3127 unlock_extent(tree, cur, cur + iosize - 1);
3130 pg_offset += iosize;
3134 if (!PageError(page))
3135 SetPageUptodate(page);
3141 static inline void __do_contiguous_readpages(struct extent_io_tree *tree,
3142 struct page *pages[], int nr_pages,
3144 get_extent_t *get_extent,
3145 struct extent_map **em_cached,
3146 struct bio **bio, int mirror_num,
3147 unsigned long *bio_flags, int rw,
3150 struct inode *inode;
3151 struct btrfs_ordered_extent *ordered;
3154 inode = pages[0]->mapping->host;
3156 lock_extent(tree, start, end);
3157 ordered = btrfs_lookup_ordered_range(inode, start,
3161 unlock_extent(tree, start, end);
3162 btrfs_start_ordered_extent(inode, ordered, 1);
3163 btrfs_put_ordered_extent(ordered);
3166 for (index = 0; index < nr_pages; index++) {
3167 __do_readpage(tree, pages[index], get_extent, em_cached, bio,
3168 mirror_num, bio_flags, rw, prev_em_start);
3169 page_cache_release(pages[index]);
3173 static void __extent_readpages(struct extent_io_tree *tree,
3174 struct page *pages[],
3175 int nr_pages, get_extent_t *get_extent,
3176 struct extent_map **em_cached,
3177 struct bio **bio, int mirror_num,
3178 unsigned long *bio_flags, int rw,
3185 int first_index = 0;
3187 for (index = 0; index < nr_pages; index++) {
3188 page_start = page_offset(pages[index]);
3191 end = start + PAGE_CACHE_SIZE - 1;
3192 first_index = index;
3193 } else if (end + 1 == page_start) {
3194 end += PAGE_CACHE_SIZE;
3196 __do_contiguous_readpages(tree, &pages[first_index],
3197 index - first_index, start,
3198 end, get_extent, em_cached,
3199 bio, mirror_num, bio_flags,
3202 end = start + PAGE_CACHE_SIZE - 1;
3203 first_index = index;
3208 __do_contiguous_readpages(tree, &pages[first_index],
3209 index - first_index, start,
3210 end, get_extent, em_cached, bio,
3211 mirror_num, bio_flags, rw,
3215 static int __extent_read_full_page(struct extent_io_tree *tree,
3217 get_extent_t *get_extent,
3218 struct bio **bio, int mirror_num,
3219 unsigned long *bio_flags, int rw)
3221 struct inode *inode = page->mapping->host;
3222 struct btrfs_ordered_extent *ordered;
3223 u64 start = page_offset(page);
3224 u64 end = start + PAGE_CACHE_SIZE - 1;
3228 lock_extent(tree, start, end);
3229 ordered = btrfs_lookup_ordered_extent(inode, start);
3232 unlock_extent(tree, start, end);
3233 btrfs_start_ordered_extent(inode, ordered, 1);
3234 btrfs_put_ordered_extent(ordered);
3237 ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
3238 bio_flags, rw, NULL);
3242 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3243 get_extent_t *get_extent, int mirror_num)
3245 struct bio *bio = NULL;
3246 unsigned long bio_flags = 0;
3249 ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3252 ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
3256 int extent_read_full_page_nolock(struct extent_io_tree *tree, struct page *page,
3257 get_extent_t *get_extent, int mirror_num)
3259 struct bio *bio = NULL;
3260 unsigned long bio_flags = EXTENT_BIO_PARENT_LOCKED;
3263 ret = __do_readpage(tree, page, get_extent, NULL, &bio, mirror_num,
3264 &bio_flags, READ, NULL);
3266 ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
3270 static noinline void update_nr_written(struct page *page,
3271 struct writeback_control *wbc,
3272 unsigned long nr_written)
3274 wbc->nr_to_write -= nr_written;
3275 if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
3276 wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
3277 page->mapping->writeback_index = page->index + nr_written;
3281 * helper for __extent_writepage, doing all of the delayed allocation setup.
3283 * This returns 1 if our fill_delalloc function did all the work required
3284 * to write the page (copy into inline extent). In this case the IO has
3285 * been started and the page is already unlocked.
3287 * This returns 0 if all went well (page still locked)
3288 * This returns < 0 if there were errors (page still locked)
3290 static noinline_for_stack int writepage_delalloc(struct inode *inode,
3291 struct page *page, struct writeback_control *wbc,
3292 struct extent_page_data *epd,
3294 unsigned long *nr_written)
3296 struct extent_io_tree *tree = epd->tree;
3297 u64 page_end = delalloc_start + PAGE_CACHE_SIZE - 1;
3299 u64 delalloc_to_write = 0;
3300 u64 delalloc_end = 0;
3302 int page_started = 0;
3304 if (epd->extent_locked || !tree->ops || !tree->ops->fill_delalloc)
3307 while (delalloc_end < page_end) {
3308 nr_delalloc = find_lock_delalloc_range(inode, tree,
3312 BTRFS_MAX_EXTENT_SIZE);
3313 if (nr_delalloc == 0) {
3314 delalloc_start = delalloc_end + 1;
3317 ret = tree->ops->fill_delalloc(inode, page,
3322 /* File system has been set read-only */
3325 /* fill_delalloc should be return < 0 for error
3326 * but just in case, we use > 0 here meaning the
3327 * IO is started, so we don't want to return > 0
3328 * unless things are going well.
3330 ret = ret < 0 ? ret : -EIO;
3334 * delalloc_end is already one less than the total
3335 * length, so we don't subtract one from
3338 delalloc_to_write += (delalloc_end - delalloc_start +
3341 delalloc_start = delalloc_end + 1;
3343 if (wbc->nr_to_write < delalloc_to_write) {
3346 if (delalloc_to_write < thresh * 2)
3347 thresh = delalloc_to_write;
3348 wbc->nr_to_write = min_t(u64, delalloc_to_write,
3352 /* did the fill delalloc function already unlock and start
3357 * we've unlocked the page, so we can't update
3358 * the mapping's writeback index, just update
3361 wbc->nr_to_write -= *nr_written;
3372 * helper for __extent_writepage. This calls the writepage start hooks,
3373 * and does the loop to map the page into extents and bios.
3375 * We return 1 if the IO is started and the page is unlocked,
3376 * 0 if all went well (page still locked)
3377 * < 0 if there were errors (page still locked)
3379 static noinline_for_stack int __extent_writepage_io(struct inode *inode,
3381 struct writeback_control *wbc,
3382 struct extent_page_data *epd,
3384 unsigned long nr_written,
3385 int write_flags, int *nr_ret)
3387 struct extent_io_tree *tree = epd->tree;
3388 u64 start = page_offset(page);
3389 u64 page_end = start + PAGE_CACHE_SIZE - 1;
3396 struct extent_state *cached_state = NULL;
3397 struct extent_map *em;
3398 struct block_device *bdev;
3399 size_t pg_offset = 0;
3405 if (tree->ops && tree->ops->writepage_start_hook) {
3406 ret = tree->ops->writepage_start_hook(page, start,
3409 /* Fixup worker will requeue */
3411 wbc->pages_skipped++;
3413 redirty_page_for_writepage(wbc, page);
3415 update_nr_written(page, wbc, nr_written);
3423 * we don't want to touch the inode after unlocking the page,
3424 * so we update the mapping writeback index now
3426 update_nr_written(page, wbc, nr_written + 1);
3429 if (i_size <= start) {
3430 if (tree->ops && tree->ops->writepage_end_io_hook)
3431 tree->ops->writepage_end_io_hook(page, start,
3436 blocksize = inode->i_sb->s_blocksize;
3438 while (cur <= end) {
3440 if (cur >= i_size) {
3441 if (tree->ops && tree->ops->writepage_end_io_hook)
3442 tree->ops->writepage_end_io_hook(page, cur,
3446 em = epd->get_extent(inode, page, pg_offset, cur,
3448 if (IS_ERR_OR_NULL(em)) {
3450 ret = PTR_ERR_OR_ZERO(em);
3454 extent_offset = cur - em->start;
3455 em_end = extent_map_end(em);
3456 BUG_ON(em_end <= cur);
3458 iosize = min(em_end - cur, end - cur + 1);
3459 iosize = ALIGN(iosize, blocksize);
3460 sector = (em->block_start + extent_offset) >> 9;
3462 block_start = em->block_start;
3463 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3464 free_extent_map(em);
3468 * compressed and inline extents are written through other
3471 if (compressed || block_start == EXTENT_MAP_HOLE ||
3472 block_start == EXTENT_MAP_INLINE) {
3474 * end_io notification does not happen here for
3475 * compressed extents
3477 if (!compressed && tree->ops &&
3478 tree->ops->writepage_end_io_hook)
3479 tree->ops->writepage_end_io_hook(page, cur,
3482 else if (compressed) {
3483 /* we don't want to end_page_writeback on
3484 * a compressed extent. this happens
3491 pg_offset += iosize;
3495 if (tree->ops && tree->ops->writepage_io_hook) {
3496 ret = tree->ops->writepage_io_hook(page, cur,
3504 unsigned long max_nr = (i_size >> PAGE_CACHE_SHIFT) + 1;
3506 set_range_writeback(tree, cur, cur + iosize - 1);
3507 if (!PageWriteback(page)) {
3508 btrfs_err(BTRFS_I(inode)->root->fs_info,
3509 "page %lu not writeback, cur %llu end %llu",
3510 page->index, cur, end);
3513 ret = submit_extent_page(write_flags, tree, wbc, page,
3514 sector, iosize, pg_offset,
3515 bdev, &epd->bio, max_nr,
3516 end_bio_extent_writepage,
3522 pg_offset += iosize;
3530 /* drop our reference on any cached states */
3531 free_extent_state(cached_state);
3536 * the writepage semantics are similar to regular writepage. extent
3537 * records are inserted to lock ranges in the tree, and as dirty areas
3538 * are found, they are marked writeback. Then the lock bits are removed
3539 * and the end_io handler clears the writeback ranges
3541 static int __extent_writepage(struct page *page, struct writeback_control *wbc,
3544 struct inode *inode = page->mapping->host;
3545 struct extent_page_data *epd = data;
3546 u64 start = page_offset(page);
3547 u64 page_end = start + PAGE_CACHE_SIZE - 1;
3550 size_t pg_offset = 0;
3551 loff_t i_size = i_size_read(inode);
3552 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
3554 unsigned long nr_written = 0;
3556 if (wbc->sync_mode == WB_SYNC_ALL)
3557 write_flags = WRITE_SYNC;
3559 write_flags = WRITE;
3561 trace___extent_writepage(page, inode, wbc);
3563 WARN_ON(!PageLocked(page));
3565 ClearPageError(page);
3567 pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
3568 if (page->index > end_index ||
3569 (page->index == end_index && !pg_offset)) {
3570 page->mapping->a_ops->invalidatepage(page, 0, PAGE_CACHE_SIZE);
3575 if (page->index == end_index) {
3578 userpage = kmap_atomic(page);
3579 memset(userpage + pg_offset, 0,
3580 PAGE_CACHE_SIZE - pg_offset);
3581 kunmap_atomic(userpage);
3582 flush_dcache_page(page);
3587 set_page_extent_mapped(page);
3589 ret = writepage_delalloc(inode, page, wbc, epd, start, &nr_written);
3595 ret = __extent_writepage_io(inode, page, wbc, epd,
3596 i_size, nr_written, write_flags, &nr);
3602 /* make sure the mapping tag for page dirty gets cleared */
3603 set_page_writeback(page);
3604 end_page_writeback(page);
3606 if (PageError(page)) {
3607 ret = ret < 0 ? ret : -EIO;
3608 end_extent_writepage(page, ret, start, page_end);
3617 void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3619 wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
3620 TASK_UNINTERRUPTIBLE);
3623 static noinline_for_stack int
3624 lock_extent_buffer_for_io(struct extent_buffer *eb,
3625 struct btrfs_fs_info *fs_info,
3626 struct extent_page_data *epd)
3628 unsigned long i, num_pages;
3632 if (!btrfs_try_tree_write_lock(eb)) {
3634 flush_write_bio(epd);
3635 btrfs_tree_lock(eb);
3638 if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
3639 btrfs_tree_unlock(eb);
3643 flush_write_bio(epd);
3647 wait_on_extent_buffer_writeback(eb);
3648 btrfs_tree_lock(eb);
3649 if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
3651 btrfs_tree_unlock(eb);
3656 * We need to do this to prevent races in people who check if the eb is
3657 * under IO since we can end up having no IO bits set for a short period
3660 spin_lock(&eb->refs_lock);
3661 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3662 set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3663 spin_unlock(&eb->refs_lock);
3664 btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3665 __percpu_counter_add(&fs_info->dirty_metadata_bytes,
3667 fs_info->dirty_metadata_batch);
3670 spin_unlock(&eb->refs_lock);
3673 btrfs_tree_unlock(eb);
3678 num_pages = num_extent_pages(eb->start, eb->len);
3679 for (i = 0; i < num_pages; i++) {
3680 struct page *p = eb->pages[i];
3682 if (!trylock_page(p)) {
3684 flush_write_bio(epd);
3694 static void end_extent_buffer_writeback(struct extent_buffer *eb)
3696 clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3697 smp_mb__after_atomic();
3698 wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
3701 static void set_btree_ioerr(struct page *page)
3703 struct extent_buffer *eb = (struct extent_buffer *)page->private;
3704 struct btrfs_inode *btree_ino = BTRFS_I(eb->fs_info->btree_inode);
3707 if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
3711 * If writeback for a btree extent that doesn't belong to a log tree
3712 * failed, increment the counter transaction->eb_write_errors.
3713 * We do this because while the transaction is running and before it's
3714 * committing (when we call filemap_fdata[write|wait]_range against
3715 * the btree inode), we might have
3716 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
3717 * returns an error or an error happens during writeback, when we're
3718 * committing the transaction we wouldn't know about it, since the pages
3719 * can be no longer dirty nor marked anymore for writeback (if a
3720 * subsequent modification to the extent buffer didn't happen before the
3721 * transaction commit), which makes filemap_fdata[write|wait]_range not
3722 * able to find the pages tagged with SetPageError at transaction
3723 * commit time. So if this happens we must abort the transaction,
3724 * otherwise we commit a super block with btree roots that point to
3725 * btree nodes/leafs whose content on disk is invalid - either garbage
3726 * or the content of some node/leaf from a past generation that got
3727 * cowed or deleted and is no longer valid.
3729 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
3730 * not be enough - we need to distinguish between log tree extents vs
3731 * non-log tree extents, and the next filemap_fdatawait_range() call
3732 * will catch and clear such errors in the mapping - and that call might
3733 * be from a log sync and not from a transaction commit. Also, checking
3734 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
3735 * not done and would not be reliable - the eb might have been released
3736 * from memory and reading it back again means that flag would not be
3737 * set (since it's a runtime flag, not persisted on disk).
3739 * Using the flags below in the btree inode also makes us achieve the
3740 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
3741 * writeback for all dirty pages and before filemap_fdatawait_range()
3742 * is called, the writeback for all dirty pages had already finished
3743 * with errors - because we were not using AS_EIO/AS_ENOSPC,
3744 * filemap_fdatawait_range() would return success, as it could not know
3745 * that writeback errors happened (the pages were no longer tagged for
3748 switch (eb->log_index) {
3750 set_bit(BTRFS_INODE_BTREE_ERR, &btree_ino->runtime_flags);
3753 set_bit(BTRFS_INODE_BTREE_LOG1_ERR, &btree_ino->runtime_flags);
3756 set_bit(BTRFS_INODE_BTREE_LOG2_ERR, &btree_ino->runtime_flags);
3759 BUG(); /* unexpected, logic error */
3763 static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
3765 struct bio_vec *bvec;
3766 struct extent_buffer *eb;
3769 bio_for_each_segment_all(bvec, bio, i) {
3770 struct page *page = bvec->bv_page;
3772 eb = (struct extent_buffer *)page->private;
3774 done = atomic_dec_and_test(&eb->io_pages);
3776 if (err || test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
3777 ClearPageUptodate(page);
3778 set_btree_ioerr(page);
3781 end_page_writeback(page);
3786 end_extent_buffer_writeback(eb);
3792 static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3793 struct btrfs_fs_info *fs_info,
3794 struct writeback_control *wbc,
3795 struct extent_page_data *epd)
3797 struct block_device *bdev = fs_info->fs_devices->latest_bdev;
3798 struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3799 u64 offset = eb->start;
3800 unsigned long i, num_pages;
3801 unsigned long bio_flags = 0;
3802 int rw = (epd->sync_io ? WRITE_SYNC : WRITE) | REQ_META;
3805 clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
3806 num_pages = num_extent_pages(eb->start, eb->len);
3807 atomic_set(&eb->io_pages, num_pages);
3808 if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
3809 bio_flags = EXTENT_BIO_TREE_LOG;
3811 for (i = 0; i < num_pages; i++) {
3812 struct page *p = eb->pages[i];
3814 clear_page_dirty_for_io(p);
3815 set_page_writeback(p);
3816 ret = submit_extent_page(rw, tree, wbc, p, offset >> 9,
3817 PAGE_CACHE_SIZE, 0, bdev, &epd->bio,
3818 -1, end_bio_extent_buffer_writepage,
3819 0, epd->bio_flags, bio_flags, false);
3820 epd->bio_flags = bio_flags;
3823 end_page_writeback(p);
3824 if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
3825 end_extent_buffer_writeback(eb);
3829 offset += PAGE_CACHE_SIZE;
3830 update_nr_written(p, wbc, 1);
3834 if (unlikely(ret)) {
3835 for (; i < num_pages; i++) {
3836 struct page *p = eb->pages[i];
3837 clear_page_dirty_for_io(p);
3845 int btree_write_cache_pages(struct address_space *mapping,
3846 struct writeback_control *wbc)
3848 struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
3849 struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
3850 struct extent_buffer *eb, *prev_eb = NULL;
3851 struct extent_page_data epd = {
3855 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
3860 int nr_to_write_done = 0;
3861 struct pagevec pvec;
3864 pgoff_t end; /* Inclusive */
3868 pagevec_init(&pvec, 0);
3869 if (wbc->range_cyclic) {
3870 index = mapping->writeback_index; /* Start from prev offset */
3873 index = wbc->range_start >> PAGE_CACHE_SHIFT;
3874 end = wbc->range_end >> PAGE_CACHE_SHIFT;
3877 if (wbc->sync_mode == WB_SYNC_ALL)
3878 tag = PAGECACHE_TAG_TOWRITE;
3880 tag = PAGECACHE_TAG_DIRTY;
3882 if (wbc->sync_mode == WB_SYNC_ALL)
3883 tag_pages_for_writeback(mapping, index, end);
3884 while (!done && !nr_to_write_done && (index <= end) &&
3885 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3886 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3890 for (i = 0; i < nr_pages; i++) {
3891 struct page *page = pvec.pages[i];
3893 if (!PagePrivate(page))
3896 if (!wbc->range_cyclic && page->index > end) {
3901 spin_lock(&mapping->private_lock);
3902 if (!PagePrivate(page)) {
3903 spin_unlock(&mapping->private_lock);
3907 eb = (struct extent_buffer *)page->private;
3910 * Shouldn't happen and normally this would be a BUG_ON
3911 * but no sense in crashing the users box for something
3912 * we can survive anyway.
3915 spin_unlock(&mapping->private_lock);
3919 if (eb == prev_eb) {
3920 spin_unlock(&mapping->private_lock);
3924 ret = atomic_inc_not_zero(&eb->refs);
3925 spin_unlock(&mapping->private_lock);
3930 ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
3932 free_extent_buffer(eb);
3936 ret = write_one_eb(eb, fs_info, wbc, &epd);
3939 free_extent_buffer(eb);
3942 free_extent_buffer(eb);
3945 * the filesystem may choose to bump up nr_to_write.
3946 * We have to make sure to honor the new nr_to_write
3949 nr_to_write_done = wbc->nr_to_write <= 0;
3951 pagevec_release(&pvec);
3954 if (!scanned && !done) {
3956 * We hit the last page and there is more work to be done: wrap
3957 * back to the start of the file
3963 flush_write_bio(&epd);
3968 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3969 * @mapping: address space structure to write
3970 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
3971 * @writepage: function called for each page
3972 * @data: data passed to writepage function
3974 * If a page is already under I/O, write_cache_pages() skips it, even
3975 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
3976 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
3977 * and msync() need to guarantee that all the data which was dirty at the time
3978 * the call was made get new I/O started against them. If wbc->sync_mode is
3979 * WB_SYNC_ALL then we were called for data integrity and we must wait for
3980 * existing IO to complete.
3982 static int extent_write_cache_pages(struct extent_io_tree *tree,
3983 struct address_space *mapping,
3984 struct writeback_control *wbc,
3985 writepage_t writepage, void *data,
3986 void (*flush_fn)(void *))
3988 struct inode *inode = mapping->host;
3992 int nr_to_write_done = 0;
3993 struct pagevec pvec;
3996 pgoff_t end; /* Inclusive */
4001 * We have to hold onto the inode so that ordered extents can do their
4002 * work when the IO finishes. The alternative to this is failing to add
4003 * an ordered extent if the igrab() fails there and that is a huge pain
4004 * to deal with, so instead just hold onto the inode throughout the
4005 * writepages operation. If it fails here we are freeing up the inode
4006 * anyway and we'd rather not waste our time writing out stuff that is
4007 * going to be truncated anyway.
4012 pagevec_init(&pvec, 0);
4013 if (wbc->range_cyclic) {
4014 index = mapping->writeback_index; /* Start from prev offset */
4017 index = wbc->range_start >> PAGE_CACHE_SHIFT;
4018 end = wbc->range_end >> PAGE_CACHE_SHIFT;
4021 if (wbc->sync_mode == WB_SYNC_ALL)
4022 tag = PAGECACHE_TAG_TOWRITE;
4024 tag = PAGECACHE_TAG_DIRTY;
4026 if (wbc->sync_mode == WB_SYNC_ALL)
4027 tag_pages_for_writeback(mapping, index, end);
4028 while (!done && !nr_to_write_done && (index <= end) &&
4029 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
4030 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
4034 for (i = 0; i < nr_pages; i++) {
4035 struct page *page = pvec.pages[i];
4038 * At this point we hold neither mapping->tree_lock nor
4039 * lock on the page itself: the page may be truncated or
4040 * invalidated (changing page->mapping to NULL), or even
4041 * swizzled back from swapper_space to tmpfs file
4044 if (!trylock_page(page)) {
4049 if (unlikely(page->mapping != mapping)) {
4054 if (!wbc->range_cyclic && page->index > end) {
4060 if (wbc->sync_mode != WB_SYNC_NONE) {
4061 if (PageWriteback(page))
4063 wait_on_page_writeback(page);
4066 if (PageWriteback(page) ||
4067 !clear_page_dirty_for_io(page)) {
4072 ret = (*writepage)(page, wbc, data);
4074 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
4078 if (!err && ret < 0)
4082 * the filesystem may choose to bump up nr_to_write.
4083 * We have to make sure to honor the new nr_to_write
4086 nr_to_write_done = wbc->nr_to_write <= 0;
4088 pagevec_release(&pvec);
4091 if (!scanned && !done && !err) {
4093 * We hit the last page and there is more work to be done: wrap
4094 * back to the start of the file
4100 btrfs_add_delayed_iput(inode);
4104 static void flush_epd_write_bio(struct extent_page_data *epd)
4113 ret = submit_one_bio(rw, epd->bio, 0, epd->bio_flags);
4114 BUG_ON(ret < 0); /* -ENOMEM */
4119 static noinline void flush_write_bio(void *data)
4121 struct extent_page_data *epd = data;
4122 flush_epd_write_bio(epd);
4125 int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
4126 get_extent_t *get_extent,
4127 struct writeback_control *wbc)
4130 struct extent_page_data epd = {
4133 .get_extent = get_extent,
4135 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4139 ret = __extent_writepage(page, wbc, &epd);
4141 flush_epd_write_bio(&epd);
4145 int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
4146 u64 start, u64 end, get_extent_t *get_extent,
4150 struct address_space *mapping = inode->i_mapping;
4152 unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
4155 struct extent_page_data epd = {
4158 .get_extent = get_extent,
4160 .sync_io = mode == WB_SYNC_ALL,
4163 struct writeback_control wbc_writepages = {
4165 .nr_to_write = nr_pages * 2,
4166 .range_start = start,
4167 .range_end = end + 1,
4170 while (start <= end) {
4171 page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
4172 if (clear_page_dirty_for_io(page))
4173 ret = __extent_writepage(page, &wbc_writepages, &epd);
4175 if (tree->ops && tree->ops->writepage_end_io_hook)
4176 tree->ops->writepage_end_io_hook(page, start,
4177 start + PAGE_CACHE_SIZE - 1,
4181 page_cache_release(page);
4182 start += PAGE_CACHE_SIZE;
4185 flush_epd_write_bio(&epd);
4189 int extent_writepages(struct extent_io_tree *tree,
4190 struct address_space *mapping,
4191 get_extent_t *get_extent,
4192 struct writeback_control *wbc)
4195 struct extent_page_data epd = {
4198 .get_extent = get_extent,
4200 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4204 ret = extent_write_cache_pages(tree, mapping, wbc,
4205 __extent_writepage, &epd,
4207 flush_epd_write_bio(&epd);
4211 int extent_readpages(struct extent_io_tree *tree,
4212 struct address_space *mapping,
4213 struct list_head *pages, unsigned nr_pages,
4214 get_extent_t get_extent)
4216 struct bio *bio = NULL;
4218 unsigned long bio_flags = 0;
4219 struct page *pagepool[16];
4221 struct extent_map *em_cached = NULL;
4223 u64 prev_em_start = (u64)-1;
4225 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
4226 page = list_entry(pages->prev, struct page, lru);
4228 prefetchw(&page->flags);
4229 list_del(&page->lru);
4230 if (add_to_page_cache_lru(page, mapping,
4231 page->index, GFP_NOFS)) {
4232 page_cache_release(page);
4236 pagepool[nr++] = page;
4237 if (nr < ARRAY_SIZE(pagepool))
4239 __extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4240 &bio, 0, &bio_flags, READ, &prev_em_start);
4244 __extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4245 &bio, 0, &bio_flags, READ, &prev_em_start);
4248 free_extent_map(em_cached);
4250 BUG_ON(!list_empty(pages));
4252 return submit_one_bio(READ, bio, 0, bio_flags);
4257 * basic invalidatepage code, this waits on any locked or writeback
4258 * ranges corresponding to the page, and then deletes any extent state
4259 * records from the tree
4261 int extent_invalidatepage(struct extent_io_tree *tree,
4262 struct page *page, unsigned long offset)
4264 struct extent_state *cached_state = NULL;
4265 u64 start = page_offset(page);
4266 u64 end = start + PAGE_CACHE_SIZE - 1;
4267 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
4269 start += ALIGN(offset, blocksize);
4273 lock_extent_bits(tree, start, end, 0, &cached_state);
4274 wait_on_page_writeback(page);
4275 clear_extent_bit(tree, start, end,
4276 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
4277 EXTENT_DO_ACCOUNTING,
4278 1, 1, &cached_state, GFP_NOFS);
4283 * a helper for releasepage, this tests for areas of the page that
4284 * are locked or under IO and drops the related state bits if it is safe
4287 static int try_release_extent_state(struct extent_map_tree *map,
4288 struct extent_io_tree *tree,
4289 struct page *page, gfp_t mask)
4291 u64 start = page_offset(page);
4292 u64 end = start + PAGE_CACHE_SIZE - 1;
4295 if (test_range_bit(tree, start, end,
4296 EXTENT_IOBITS, 0, NULL))
4299 if ((mask & GFP_NOFS) == GFP_NOFS)
4302 * at this point we can safely clear everything except the
4303 * locked bit and the nodatasum bit
4305 ret = clear_extent_bit(tree, start, end,
4306 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
4309 /* if clear_extent_bit failed for enomem reasons,
4310 * we can't allow the release to continue.
4321 * a helper for releasepage. As long as there are no locked extents
4322 * in the range corresponding to the page, both state records and extent
4323 * map records are removed
4325 int try_release_extent_mapping(struct extent_map_tree *map,
4326 struct extent_io_tree *tree, struct page *page,
4329 struct extent_map *em;
4330 u64 start = page_offset(page);
4331 u64 end = start + PAGE_CACHE_SIZE - 1;
4333 if ((mask & __GFP_WAIT) &&
4334 page->mapping->host->i_size > 16 * 1024 * 1024) {
4336 while (start <= end) {
4337 len = end - start + 1;
4338 write_lock(&map->lock);
4339 em = lookup_extent_mapping(map, start, len);
4341 write_unlock(&map->lock);
4344 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
4345 em->start != start) {
4346 write_unlock(&map->lock);
4347 free_extent_map(em);
4350 if (!test_range_bit(tree, em->start,
4351 extent_map_end(em) - 1,
4352 EXTENT_LOCKED | EXTENT_WRITEBACK,
4354 remove_extent_mapping(map, em);
4355 /* once for the rb tree */
4356 free_extent_map(em);
4358 start = extent_map_end(em);
4359 write_unlock(&map->lock);
4362 free_extent_map(em);
4365 return try_release_extent_state(map, tree, page, mask);
4369 * helper function for fiemap, which doesn't want to see any holes.
4370 * This maps until we find something past 'last'
4372 static struct extent_map *get_extent_skip_holes(struct inode *inode,
4375 get_extent_t *get_extent)
4377 u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
4378 struct extent_map *em;
4385 len = last - offset;
4388 len = ALIGN(len, sectorsize);
4389 em = get_extent(inode, NULL, 0, offset, len, 0);
4390 if (IS_ERR_OR_NULL(em))
4393 /* if this isn't a hole return it */
4394 if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
4395 em->block_start != EXTENT_MAP_HOLE) {
4399 /* this is a hole, advance to the next extent */
4400 offset = extent_map_end(em);
4401 free_extent_map(em);
4408 int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4409 __u64 start, __u64 len, get_extent_t *get_extent)
4413 u64 max = start + len;
4417 u64 last_for_get_extent = 0;
4419 u64 isize = i_size_read(inode);
4420 struct btrfs_key found_key;
4421 struct extent_map *em = NULL;
4422 struct extent_state *cached_state = NULL;
4423 struct btrfs_path *path;
4424 struct btrfs_root *root = BTRFS_I(inode)->root;
4433 path = btrfs_alloc_path();
4436 path->leave_spinning = 1;
4438 start = round_down(start, BTRFS_I(inode)->root->sectorsize);
4439 len = round_up(max, BTRFS_I(inode)->root->sectorsize) - start;
4442 * lookup the last file extent. We're not using i_size here
4443 * because there might be preallocation past i_size
4445 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode), -1,
4448 btrfs_free_path(path);
4453 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
4454 found_type = found_key.type;
4456 /* No extents, but there might be delalloc bits */
4457 if (found_key.objectid != btrfs_ino(inode) ||
4458 found_type != BTRFS_EXTENT_DATA_KEY) {
4459 /* have to trust i_size as the end */
4461 last_for_get_extent = isize;
4464 * remember the start of the last extent. There are a
4465 * bunch of different factors that go into the length of the
4466 * extent, so its much less complex to remember where it started
4468 last = found_key.offset;
4469 last_for_get_extent = last + 1;
4471 btrfs_release_path(path);
4474 * we might have some extents allocated but more delalloc past those
4475 * extents. so, we trust isize unless the start of the last extent is
4480 last_for_get_extent = isize;
4483 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1, 0,
4486 em = get_extent_skip_holes(inode, start, last_for_get_extent,
4496 u64 offset_in_extent = 0;
4498 /* break if the extent we found is outside the range */
4499 if (em->start >= max || extent_map_end(em) < off)
4503 * get_extent may return an extent that starts before our
4504 * requested range. We have to make sure the ranges
4505 * we return to fiemap always move forward and don't
4506 * overlap, so adjust the offsets here
4508 em_start = max(em->start, off);
4511 * record the offset from the start of the extent
4512 * for adjusting the disk offset below. Only do this if the
4513 * extent isn't compressed since our in ram offset may be past
4514 * what we have actually allocated on disk.
4516 if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4517 offset_in_extent = em_start - em->start;
4518 em_end = extent_map_end(em);
4519 em_len = em_end - em_start;
4524 * bump off for our next call to get_extent
4526 off = extent_map_end(em);
4530 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
4532 flags |= FIEMAP_EXTENT_LAST;
4533 } else if (em->block_start == EXTENT_MAP_INLINE) {
4534 flags |= (FIEMAP_EXTENT_DATA_INLINE |
4535 FIEMAP_EXTENT_NOT_ALIGNED);
4536 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
4537 flags |= (FIEMAP_EXTENT_DELALLOC |
4538 FIEMAP_EXTENT_UNKNOWN);
4539 } else if (fieinfo->fi_extents_max) {
4540 u64 bytenr = em->block_start -
4541 (em->start - em->orig_start);
4543 disko = em->block_start + offset_in_extent;
4546 * As btrfs supports shared space, this information
4547 * can be exported to userspace tools via
4548 * flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0
4549 * then we're just getting a count and we can skip the
4552 ret = btrfs_check_shared(NULL, root->fs_info,
4554 btrfs_ino(inode), bytenr);
4558 flags |= FIEMAP_EXTENT_SHARED;
4561 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4562 flags |= FIEMAP_EXTENT_ENCODED;
4563 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
4564 flags |= FIEMAP_EXTENT_UNWRITTEN;
4566 free_extent_map(em);
4568 if ((em_start >= last) || em_len == (u64)-1 ||
4569 (last == (u64)-1 && isize <= em_end)) {
4570 flags |= FIEMAP_EXTENT_LAST;
4574 /* now scan forward to see if this is really the last extent. */
4575 em = get_extent_skip_holes(inode, off, last_for_get_extent,
4582 flags |= FIEMAP_EXTENT_LAST;
4585 ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
4594 free_extent_map(em);
4596 btrfs_free_path(path);
4597 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4598 &cached_state, GFP_NOFS);
4602 static void __free_extent_buffer(struct extent_buffer *eb)
4604 btrfs_leak_debug_del(&eb->leak_list);
4605 kmem_cache_free(extent_buffer_cache, eb);
4608 int extent_buffer_under_io(struct extent_buffer *eb)
4610 return (atomic_read(&eb->io_pages) ||
4611 test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
4612 test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4616 * Helper for releasing extent buffer page.
4618 static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
4620 unsigned long index;
4622 int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4624 BUG_ON(extent_buffer_under_io(eb));
4626 index = num_extent_pages(eb->start, eb->len);
4632 page = eb->pages[index];
4636 spin_lock(&page->mapping->private_lock);
4638 * We do this since we'll remove the pages after we've
4639 * removed the eb from the radix tree, so we could race
4640 * and have this page now attached to the new eb. So
4641 * only clear page_private if it's still connected to
4644 if (PagePrivate(page) &&
4645 page->private == (unsigned long)eb) {
4646 BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4647 BUG_ON(PageDirty(page));
4648 BUG_ON(PageWriteback(page));
4650 * We need to make sure we haven't be attached
4653 ClearPagePrivate(page);
4654 set_page_private(page, 0);
4655 /* One for the page private */
4656 page_cache_release(page);
4660 spin_unlock(&page->mapping->private_lock);
4662 /* One for when we alloced the page */
4663 page_cache_release(page);
4664 } while (index != 0);
4668 * Helper for releasing the extent buffer.
4670 static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
4672 btrfs_release_extent_buffer_page(eb);
4673 __free_extent_buffer(eb);
4676 static struct extent_buffer *
4677 __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
4680 struct extent_buffer *eb = NULL;
4682 eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
4685 eb->fs_info = fs_info;
4687 rwlock_init(&eb->lock);
4688 atomic_set(&eb->write_locks, 0);
4689 atomic_set(&eb->read_locks, 0);
4690 atomic_set(&eb->blocking_readers, 0);
4691 atomic_set(&eb->blocking_writers, 0);
4692 atomic_set(&eb->spinning_readers, 0);
4693 atomic_set(&eb->spinning_writers, 0);
4694 eb->lock_nested = 0;
4695 init_waitqueue_head(&eb->write_lock_wq);
4696 init_waitqueue_head(&eb->read_lock_wq);
4698 btrfs_leak_debug_add(&eb->leak_list, &buffers);
4700 spin_lock_init(&eb->refs_lock);
4701 atomic_set(&eb->refs, 1);
4702 atomic_set(&eb->io_pages, 0);
4705 * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
4707 BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
4708 > MAX_INLINE_EXTENT_BUFFER_SIZE);
4709 BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
4714 struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
4718 struct extent_buffer *new;
4719 unsigned long num_pages = num_extent_pages(src->start, src->len);
4721 new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
4725 for (i = 0; i < num_pages; i++) {
4726 p = alloc_page(GFP_NOFS);
4728 btrfs_release_extent_buffer(new);
4731 attach_extent_buffer_page(new, p);
4732 WARN_ON(PageDirty(p));
4737 copy_extent_buffer(new, src, 0, 0, src->len);
4738 set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
4739 set_bit(EXTENT_BUFFER_DUMMY, &new->bflags);
4744 struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4747 struct extent_buffer *eb;
4749 unsigned long num_pages;
4754 * Called only from tests that don't always have a fs_info
4755 * available, but we know that nodesize is 4096
4759 len = fs_info->tree_root->nodesize;
4761 num_pages = num_extent_pages(0, len);
4763 eb = __alloc_extent_buffer(fs_info, start, len);
4767 for (i = 0; i < num_pages; i++) {
4768 eb->pages[i] = alloc_page(GFP_NOFS);
4772 set_extent_buffer_uptodate(eb);
4773 btrfs_set_header_nritems(eb, 0);
4774 set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4779 __free_page(eb->pages[i - 1]);
4780 __free_extent_buffer(eb);
4784 static void check_buffer_tree_ref(struct extent_buffer *eb)
4787 /* the ref bit is tricky. We have to make sure it is set
4788 * if we have the buffer dirty. Otherwise the
4789 * code to free a buffer can end up dropping a dirty
4792 * Once the ref bit is set, it won't go away while the
4793 * buffer is dirty or in writeback, and it also won't
4794 * go away while we have the reference count on the
4797 * We can't just set the ref bit without bumping the
4798 * ref on the eb because free_extent_buffer might
4799 * see the ref bit and try to clear it. If this happens
4800 * free_extent_buffer might end up dropping our original
4801 * ref by mistake and freeing the page before we are able
4802 * to add one more ref.
4804 * So bump the ref count first, then set the bit. If someone
4805 * beat us to it, drop the ref we added.
4807 refs = atomic_read(&eb->refs);
4808 if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4811 spin_lock(&eb->refs_lock);
4812 if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4813 atomic_inc(&eb->refs);
4814 spin_unlock(&eb->refs_lock);
4817 static void mark_extent_buffer_accessed(struct extent_buffer *eb,
4818 struct page *accessed)
4820 unsigned long num_pages, i;
4822 check_buffer_tree_ref(eb);
4824 num_pages = num_extent_pages(eb->start, eb->len);
4825 for (i = 0; i < num_pages; i++) {
4826 struct page *p = eb->pages[i];
4829 mark_page_accessed(p);
4833 struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
4836 struct extent_buffer *eb;
4839 eb = radix_tree_lookup(&fs_info->buffer_radix,
4840 start >> PAGE_CACHE_SHIFT);
4841 if (eb && atomic_inc_not_zero(&eb->refs)) {
4844 * Lock our eb's refs_lock to avoid races with
4845 * free_extent_buffer. When we get our eb it might be flagged
4846 * with EXTENT_BUFFER_STALE and another task running
4847 * free_extent_buffer might have seen that flag set,
4848 * eb->refs == 2, that the buffer isn't under IO (dirty and
4849 * writeback flags not set) and it's still in the tree (flag
4850 * EXTENT_BUFFER_TREE_REF set), therefore being in the process
4851 * of decrementing the extent buffer's reference count twice.
4852 * So here we could race and increment the eb's reference count,
4853 * clear its stale flag, mark it as dirty and drop our reference
4854 * before the other task finishes executing free_extent_buffer,
4855 * which would later result in an attempt to free an extent
4856 * buffer that is dirty.
4858 if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
4859 spin_lock(&eb->refs_lock);
4860 spin_unlock(&eb->refs_lock);
4862 mark_extent_buffer_accessed(eb, NULL);
4870 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4871 struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
4874 struct extent_buffer *eb, *exists = NULL;
4877 eb = find_extent_buffer(fs_info, start);
4880 eb = alloc_dummy_extent_buffer(fs_info, start);
4883 eb->fs_info = fs_info;
4885 ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
4888 spin_lock(&fs_info->buffer_lock);
4889 ret = radix_tree_insert(&fs_info->buffer_radix,
4890 start >> PAGE_CACHE_SHIFT, eb);
4891 spin_unlock(&fs_info->buffer_lock);
4892 radix_tree_preload_end();
4893 if (ret == -EEXIST) {
4894 exists = find_extent_buffer(fs_info, start);
4900 check_buffer_tree_ref(eb);
4901 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4904 * We will free dummy extent buffer's if they come into
4905 * free_extent_buffer with a ref count of 2, but if we are using this we
4906 * want the buffers to stay in memory until we're done with them, so
4907 * bump the ref count again.
4909 atomic_inc(&eb->refs);
4912 btrfs_release_extent_buffer(eb);
4917 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4920 unsigned long len = fs_info->tree_root->nodesize;
4921 unsigned long num_pages = num_extent_pages(start, len);
4923 unsigned long index = start >> PAGE_CACHE_SHIFT;
4924 struct extent_buffer *eb;
4925 struct extent_buffer *exists = NULL;
4927 struct address_space *mapping = fs_info->btree_inode->i_mapping;
4931 eb = find_extent_buffer(fs_info, start);
4935 eb = __alloc_extent_buffer(fs_info, start, len);
4939 for (i = 0; i < num_pages; i++, index++) {
4940 p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
4944 spin_lock(&mapping->private_lock);
4945 if (PagePrivate(p)) {
4947 * We could have already allocated an eb for this page
4948 * and attached one so lets see if we can get a ref on
4949 * the existing eb, and if we can we know it's good and
4950 * we can just return that one, else we know we can just
4951 * overwrite page->private.
4953 exists = (struct extent_buffer *)p->private;
4954 if (atomic_inc_not_zero(&exists->refs)) {
4955 spin_unlock(&mapping->private_lock);
4957 page_cache_release(p);
4958 mark_extent_buffer_accessed(exists, p);
4964 * Do this so attach doesn't complain and we need to
4965 * drop the ref the old guy had.
4967 ClearPagePrivate(p);
4968 WARN_ON(PageDirty(p));
4969 page_cache_release(p);
4971 attach_extent_buffer_page(eb, p);
4972 spin_unlock(&mapping->private_lock);
4973 WARN_ON(PageDirty(p));
4975 if (!PageUptodate(p))
4979 * see below about how we avoid a nasty race with release page
4980 * and why we unlock later
4984 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4986 ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
4990 spin_lock(&fs_info->buffer_lock);
4991 ret = radix_tree_insert(&fs_info->buffer_radix,
4992 start >> PAGE_CACHE_SHIFT, eb);
4993 spin_unlock(&fs_info->buffer_lock);
4994 radix_tree_preload_end();
4995 if (ret == -EEXIST) {
4996 exists = find_extent_buffer(fs_info, start);
5002 /* add one reference for the tree */
5003 check_buffer_tree_ref(eb);
5004 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
5007 * there is a race where release page may have
5008 * tried to find this extent buffer in the radix
5009 * but failed. It will tell the VM it is safe to
5010 * reclaim the, and it will clear the page private bit.
5011 * We must make sure to set the page private bit properly
5012 * after the extent buffer is in the radix tree so
5013 * it doesn't get lost
5015 SetPageChecked(eb->pages[0]);
5016 for (i = 1; i < num_pages; i++) {
5018 ClearPageChecked(p);
5021 unlock_page(eb->pages[0]);
5025 WARN_ON(!atomic_dec_and_test(&eb->refs));
5026 for (i = 0; i < num_pages; i++) {
5028 unlock_page(eb->pages[i]);
5031 btrfs_release_extent_buffer(eb);
5035 static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
5037 struct extent_buffer *eb =
5038 container_of(head, struct extent_buffer, rcu_head);
5040 __free_extent_buffer(eb);
5043 /* Expects to have eb->eb_lock already held */
5044 static int release_extent_buffer(struct extent_buffer *eb)
5046 WARN_ON(atomic_read(&eb->refs) == 0);
5047 if (atomic_dec_and_test(&eb->refs)) {
5048 if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
5049 struct btrfs_fs_info *fs_info = eb->fs_info;
5051 spin_unlock(&eb->refs_lock);
5053 spin_lock(&fs_info->buffer_lock);
5054 radix_tree_delete(&fs_info->buffer_radix,
5055 eb->start >> PAGE_CACHE_SHIFT);
5056 spin_unlock(&fs_info->buffer_lock);
5058 spin_unlock(&eb->refs_lock);
5061 /* Should be safe to release our pages at this point */
5062 btrfs_release_extent_buffer_page(eb);
5063 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5064 if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))) {
5065 __free_extent_buffer(eb);
5069 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
5072 spin_unlock(&eb->refs_lock);
5077 void free_extent_buffer(struct extent_buffer *eb)
5085 refs = atomic_read(&eb->refs);
5088 old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
5093 spin_lock(&eb->refs_lock);
5094 if (atomic_read(&eb->refs) == 2 &&
5095 test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
5096 atomic_dec(&eb->refs);
5098 if (atomic_read(&eb->refs) == 2 &&
5099 test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
5100 !extent_buffer_under_io(eb) &&
5101 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5102 atomic_dec(&eb->refs);
5105 * I know this is terrible, but it's temporary until we stop tracking
5106 * the uptodate bits and such for the extent buffers.
5108 release_extent_buffer(eb);
5111 void free_extent_buffer_stale(struct extent_buffer *eb)
5116 spin_lock(&eb->refs_lock);
5117 set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
5119 if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
5120 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5121 atomic_dec(&eb->refs);
5122 release_extent_buffer(eb);
5125 void clear_extent_buffer_dirty(struct extent_buffer *eb)
5128 unsigned long num_pages;
5131 num_pages = num_extent_pages(eb->start, eb->len);
5133 for (i = 0; i < num_pages; i++) {
5134 page = eb->pages[i];
5135 if (!PageDirty(page))
5139 WARN_ON(!PagePrivate(page));
5141 clear_page_dirty_for_io(page);
5142 spin_lock_irq(&page->mapping->tree_lock);
5143 if (!PageDirty(page)) {
5144 radix_tree_tag_clear(&page->mapping->page_tree,
5146 PAGECACHE_TAG_DIRTY);
5148 spin_unlock_irq(&page->mapping->tree_lock);
5149 ClearPageError(page);
5152 WARN_ON(atomic_read(&eb->refs) == 0);
5155 int set_extent_buffer_dirty(struct extent_buffer *eb)
5158 unsigned long num_pages;
5161 check_buffer_tree_ref(eb);
5163 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
5165 num_pages = num_extent_pages(eb->start, eb->len);
5166 WARN_ON(atomic_read(&eb->refs) == 0);
5167 WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
5169 for (i = 0; i < num_pages; i++)
5170 set_page_dirty(eb->pages[i]);
5174 int clear_extent_buffer_uptodate(struct extent_buffer *eb)
5178 unsigned long num_pages;
5180 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5181 num_pages = num_extent_pages(eb->start, eb->len);
5182 for (i = 0; i < num_pages; i++) {
5183 page = eb->pages[i];
5185 ClearPageUptodate(page);
5190 int set_extent_buffer_uptodate(struct extent_buffer *eb)
5194 unsigned long num_pages;
5196 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5197 num_pages = num_extent_pages(eb->start, eb->len);
5198 for (i = 0; i < num_pages; i++) {
5199 page = eb->pages[i];
5200 SetPageUptodate(page);
5205 int extent_buffer_uptodate(struct extent_buffer *eb)
5207 return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5210 int read_extent_buffer_pages(struct extent_io_tree *tree,
5211 struct extent_buffer *eb, u64 start, int wait,
5212 get_extent_t *get_extent, int mirror_num)
5215 unsigned long start_i;
5219 int locked_pages = 0;
5220 int all_uptodate = 1;
5221 unsigned long num_pages;
5222 unsigned long num_reads = 0;
5223 struct bio *bio = NULL;
5224 unsigned long bio_flags = 0;
5226 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
5230 WARN_ON(start < eb->start);
5231 start_i = (start >> PAGE_CACHE_SHIFT) -
5232 (eb->start >> PAGE_CACHE_SHIFT);
5237 num_pages = num_extent_pages(eb->start, eb->len);
5238 for (i = start_i; i < num_pages; i++) {
5239 page = eb->pages[i];
5240 if (wait == WAIT_NONE) {
5241 if (!trylock_page(page))
5247 if (!PageUptodate(page)) {
5254 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5258 clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
5259 eb->read_mirror = 0;
5260 atomic_set(&eb->io_pages, num_reads);
5261 for (i = start_i; i < num_pages; i++) {
5262 page = eb->pages[i];
5263 if (!PageUptodate(page)) {
5264 ClearPageError(page);
5265 err = __extent_read_full_page(tree, page,
5267 mirror_num, &bio_flags,
5277 err = submit_one_bio(READ | REQ_META, bio, mirror_num,
5283 if (ret || wait != WAIT_COMPLETE)
5286 for (i = start_i; i < num_pages; i++) {
5287 page = eb->pages[i];
5288 wait_on_page_locked(page);
5289 if (!PageUptodate(page))
5297 while (locked_pages > 0) {
5298 page = eb->pages[i];
5306 void read_extent_buffer(struct extent_buffer *eb, void *dstv,
5307 unsigned long start,
5314 char *dst = (char *)dstv;
5315 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
5316 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
5318 WARN_ON(start > eb->len);
5319 WARN_ON(start + len > eb->start + eb->len);
5321 offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5324 page = eb->pages[i];
5326 cur = min(len, (PAGE_CACHE_SIZE - offset));
5327 kaddr = page_address(page);
5328 memcpy(dst, kaddr + offset, cur);
5337 int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
5338 unsigned long start,
5345 char __user *dst = (char __user *)dstv;
5346 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
5347 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
5350 WARN_ON(start > eb->len);
5351 WARN_ON(start + len > eb->start + eb->len);
5353 offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5356 page = eb->pages[i];
5358 cur = min(len, (PAGE_CACHE_SIZE - offset));
5359 kaddr = page_address(page);
5360 if (copy_to_user(dst, kaddr + offset, cur)) {
5374 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
5375 unsigned long min_len, char **map,
5376 unsigned long *map_start,
5377 unsigned long *map_len)
5379 size_t offset = start & (PAGE_CACHE_SIZE - 1);
5382 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
5383 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
5384 unsigned long end_i = (start_offset + start + min_len - 1) >>
5391 offset = start_offset;
5395 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
5398 if (start + min_len > eb->len) {
5399 WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
5401 eb->start, eb->len, start, min_len);
5406 kaddr = page_address(p);
5407 *map = kaddr + offset;
5408 *map_len = PAGE_CACHE_SIZE - offset;
5412 int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
5413 unsigned long start,
5420 char *ptr = (char *)ptrv;
5421 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
5422 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
5425 WARN_ON(start > eb->len);
5426 WARN_ON(start + len > eb->start + eb->len);
5428 offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5431 page = eb->pages[i];
5433 cur = min(len, (PAGE_CACHE_SIZE - offset));
5435 kaddr = page_address(page);
5436 ret = memcmp(ptr, kaddr + offset, cur);
5448 void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
5449 unsigned long start, unsigned long len)
5455 char *src = (char *)srcv;
5456 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
5457 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
5459 WARN_ON(start > eb->len);
5460 WARN_ON(start + len > eb->start + eb->len);
5462 offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5465 page = eb->pages[i];
5466 WARN_ON(!PageUptodate(page));
5468 cur = min(len, PAGE_CACHE_SIZE - offset);
5469 kaddr = page_address(page);
5470 memcpy(kaddr + offset, src, cur);
5479 void memset_extent_buffer(struct extent_buffer *eb, char c,
5480 unsigned long start, unsigned long len)
5486 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
5487 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
5489 WARN_ON(start > eb->len);
5490 WARN_ON(start + len > eb->start + eb->len);
5492 offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5495 page = eb->pages[i];
5496 WARN_ON(!PageUptodate(page));
5498 cur = min(len, PAGE_CACHE_SIZE - offset);
5499 kaddr = page_address(page);
5500 memset(kaddr + offset, c, cur);
5508 void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
5509 unsigned long dst_offset, unsigned long src_offset,
5512 u64 dst_len = dst->len;
5517 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
5518 unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
5520 WARN_ON(src->len != dst_len);
5522 offset = (start_offset + dst_offset) &
5523 (PAGE_CACHE_SIZE - 1);
5526 page = dst->pages[i];
5527 WARN_ON(!PageUptodate(page));
5529 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
5531 kaddr = page_address(page);
5532 read_extent_buffer(src, kaddr + offset, src_offset, cur);
5541 static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
5543 unsigned long distance = (src > dst) ? src - dst : dst - src;
5544 return distance < len;
5547 static void copy_pages(struct page *dst_page, struct page *src_page,
5548 unsigned long dst_off, unsigned long src_off,
5551 char *dst_kaddr = page_address(dst_page);
5553 int must_memmove = 0;
5555 if (dst_page != src_page) {
5556 src_kaddr = page_address(src_page);
5558 src_kaddr = dst_kaddr;
5559 if (areas_overlap(src_off, dst_off, len))
5564 memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
5566 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5569 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5570 unsigned long src_offset, unsigned long len)
5573 size_t dst_off_in_page;
5574 size_t src_off_in_page;
5575 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
5576 unsigned long dst_i;
5577 unsigned long src_i;
5579 if (src_offset + len > dst->len) {
5580 printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
5581 "len %lu dst len %lu\n", src_offset, len, dst->len);
5584 if (dst_offset + len > dst->len) {
5585 printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
5586 "len %lu dst len %lu\n", dst_offset, len, dst->len);
5591 dst_off_in_page = (start_offset + dst_offset) &
5592 (PAGE_CACHE_SIZE - 1);
5593 src_off_in_page = (start_offset + src_offset) &
5594 (PAGE_CACHE_SIZE - 1);
5596 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
5597 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
5599 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
5601 cur = min_t(unsigned long, cur,
5602 (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
5604 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5605 dst_off_in_page, src_off_in_page, cur);
5613 void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5614 unsigned long src_offset, unsigned long len)
5617 size_t dst_off_in_page;
5618 size_t src_off_in_page;
5619 unsigned long dst_end = dst_offset + len - 1;
5620 unsigned long src_end = src_offset + len - 1;
5621 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
5622 unsigned long dst_i;
5623 unsigned long src_i;
5625 if (src_offset + len > dst->len) {
5626 printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
5627 "len %lu len %lu\n", src_offset, len, dst->len);
5630 if (dst_offset + len > dst->len) {
5631 printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
5632 "len %lu len %lu\n", dst_offset, len, dst->len);
5635 if (dst_offset < src_offset) {
5636 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
5640 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
5641 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
5643 dst_off_in_page = (start_offset + dst_end) &
5644 (PAGE_CACHE_SIZE - 1);
5645 src_off_in_page = (start_offset + src_end) &
5646 (PAGE_CACHE_SIZE - 1);
5648 cur = min_t(unsigned long, len, src_off_in_page + 1);
5649 cur = min(cur, dst_off_in_page + 1);
5650 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5651 dst_off_in_page - cur + 1,
5652 src_off_in_page - cur + 1, cur);
5660 int try_release_extent_buffer(struct page *page)
5662 struct extent_buffer *eb;
5665 * We need to make sure noboody is attaching this page to an eb right
5668 spin_lock(&page->mapping->private_lock);
5669 if (!PagePrivate(page)) {
5670 spin_unlock(&page->mapping->private_lock);
5674 eb = (struct extent_buffer *)page->private;
5678 * This is a little awful but should be ok, we need to make sure that
5679 * the eb doesn't disappear out from under us while we're looking at
5682 spin_lock(&eb->refs_lock);
5683 if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5684 spin_unlock(&eb->refs_lock);
5685 spin_unlock(&page->mapping->private_lock);
5688 spin_unlock(&page->mapping->private_lock);
5691 * If tree ref isn't set then we know the ref on this eb is a real ref,
5692 * so just return, this page will likely be freed soon anyway.
5694 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
5695 spin_unlock(&eb->refs_lock);
5699 return release_extent_buffer(eb);