1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/bitops.h>
3 #include <linux/slab.h>
6 #include <linux/pagemap.h>
7 #include <linux/page-flags.h>
8 #include <linux/spinlock.h>
9 #include <linux/blkdev.h>
10 #include <linux/swap.h>
11 #include <linux/writeback.h>
12 #include <linux/pagevec.h>
13 #include <linux/prefetch.h>
14 #include <linux/cleancache.h>
15 #include "extent_io.h"
16 #include "extent_map.h"
18 #include "btrfs_inode.h"
20 #include "check-integrity.h"
22 #include "rcu-string.h"
25 static struct kmem_cache
*extent_state_cache
;
26 static struct kmem_cache
*extent_buffer_cache
;
27 static struct bio_set
*btrfs_bioset
;
29 static inline bool extent_state_in_tree(const struct extent_state
*state
)
31 return !RB_EMPTY_NODE(&state
->rb_node
);
34 #ifdef CONFIG_BTRFS_DEBUG
35 static LIST_HEAD(buffers
);
36 static LIST_HEAD(states
);
38 static DEFINE_SPINLOCK(leak_lock
);
41 void btrfs_leak_debug_add(struct list_head
*new, struct list_head
*head
)
45 spin_lock_irqsave(&leak_lock
, flags
);
47 spin_unlock_irqrestore(&leak_lock
, flags
);
51 void btrfs_leak_debug_del(struct list_head
*entry
)
55 spin_lock_irqsave(&leak_lock
, flags
);
57 spin_unlock_irqrestore(&leak_lock
, flags
);
61 void btrfs_leak_debug_check(void)
63 struct extent_state
*state
;
64 struct extent_buffer
*eb
;
66 while (!list_empty(&states
)) {
67 state
= list_entry(states
.next
, struct extent_state
, leak_list
);
68 pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
69 state
->start
, state
->end
, state
->state
,
70 extent_state_in_tree(state
),
71 refcount_read(&state
->refs
));
72 list_del(&state
->leak_list
);
73 kmem_cache_free(extent_state_cache
, state
);
76 while (!list_empty(&buffers
)) {
77 eb
= list_entry(buffers
.next
, struct extent_buffer
, leak_list
);
78 pr_err("BTRFS: buffer leak start %llu len %lu refs %d\n",
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
)
90 if (tree
->ops
&& tree
->ops
->check_extent_io_range
)
91 tree
->ops
->check_extent_io_range(tree
->private_data
, caller
,
95 #define btrfs_leak_debug_add(new, head) do {} while (0)
96 #define btrfs_leak_debug_del(entry) do {} while (0)
97 #define btrfs_leak_debug_check() do {} while (0)
98 #define btrfs_debug_check_extent_io_range(c, s, e) do {} while (0)
101 #define BUFFER_LRU_MAX 64
106 struct rb_node rb_node
;
109 struct extent_page_data
{
111 struct extent_io_tree
*tree
;
112 get_extent_t
*get_extent
;
114 /* tells writepage not to lock the state bits for this range
115 * it still does the unlocking
117 unsigned int extent_locked
:1;
119 /* tells the submit_bio code to use REQ_SYNC */
120 unsigned int sync_io
:1;
123 static void add_extent_changeset(struct extent_state
*state
, unsigned bits
,
124 struct extent_changeset
*changeset
,
131 if (set
&& (state
->state
& bits
) == bits
)
133 if (!set
&& (state
->state
& bits
) == 0)
135 changeset
->bytes_changed
+= state
->end
- state
->start
+ 1;
136 ret
= ulist_add(&changeset
->range_changed
, state
->start
, state
->end
,
142 static noinline
void flush_write_bio(void *data
);
143 static inline struct btrfs_fs_info
*
144 tree_fs_info(struct extent_io_tree
*tree
)
147 return tree
->ops
->tree_fs_info(tree
->private_data
);
151 int __init
extent_io_init(void)
153 extent_state_cache
= kmem_cache_create("btrfs_extent_state",
154 sizeof(struct extent_state
), 0,
155 SLAB_MEM_SPREAD
, NULL
);
156 if (!extent_state_cache
)
159 extent_buffer_cache
= kmem_cache_create("btrfs_extent_buffer",
160 sizeof(struct extent_buffer
), 0,
161 SLAB_MEM_SPREAD
, NULL
);
162 if (!extent_buffer_cache
)
163 goto free_state_cache
;
165 btrfs_bioset
= bioset_create(BIO_POOL_SIZE
,
166 offsetof(struct btrfs_io_bio
, bio
),
169 goto free_buffer_cache
;
171 if (bioset_integrity_create(btrfs_bioset
, BIO_POOL_SIZE
))
177 bioset_free(btrfs_bioset
);
181 kmem_cache_destroy(extent_buffer_cache
);
182 extent_buffer_cache
= NULL
;
185 kmem_cache_destroy(extent_state_cache
);
186 extent_state_cache
= NULL
;
190 void extent_io_exit(void)
192 btrfs_leak_debug_check();
195 * Make sure all delayed rcu free are flushed before we
199 kmem_cache_destroy(extent_state_cache
);
200 kmem_cache_destroy(extent_buffer_cache
);
202 bioset_free(btrfs_bioset
);
205 void extent_io_tree_init(struct extent_io_tree
*tree
,
208 tree
->state
= RB_ROOT
;
210 tree
->dirty_bytes
= 0;
211 spin_lock_init(&tree
->lock
);
212 tree
->private_data
= private_data
;
215 static struct extent_state
*alloc_extent_state(gfp_t mask
)
217 struct extent_state
*state
;
220 * The given mask might be not appropriate for the slab allocator,
221 * drop the unsupported bits
223 mask
&= ~(__GFP_DMA32
|__GFP_HIGHMEM
);
224 state
= kmem_cache_alloc(extent_state_cache
, mask
);
228 state
->failrec
= NULL
;
229 RB_CLEAR_NODE(&state
->rb_node
);
230 btrfs_leak_debug_add(&state
->leak_list
, &states
);
231 refcount_set(&state
->refs
, 1);
232 init_waitqueue_head(&state
->wq
);
233 trace_alloc_extent_state(state
, mask
, _RET_IP_
);
237 void free_extent_state(struct extent_state
*state
)
241 if (refcount_dec_and_test(&state
->refs
)) {
242 WARN_ON(extent_state_in_tree(state
));
243 btrfs_leak_debug_del(&state
->leak_list
);
244 trace_free_extent_state(state
, _RET_IP_
);
245 kmem_cache_free(extent_state_cache
, state
);
249 static struct rb_node
*tree_insert(struct rb_root
*root
,
250 struct rb_node
*search_start
,
252 struct rb_node
*node
,
253 struct rb_node
***p_in
,
254 struct rb_node
**parent_in
)
257 struct rb_node
*parent
= NULL
;
258 struct tree_entry
*entry
;
260 if (p_in
&& parent_in
) {
266 p
= search_start
? &search_start
: &root
->rb_node
;
269 entry
= rb_entry(parent
, struct tree_entry
, rb_node
);
271 if (offset
< entry
->start
)
273 else if (offset
> entry
->end
)
280 rb_link_node(node
, parent
, p
);
281 rb_insert_color(node
, root
);
285 static struct rb_node
*__etree_search(struct extent_io_tree
*tree
, u64 offset
,
286 struct rb_node
**prev_ret
,
287 struct rb_node
**next_ret
,
288 struct rb_node
***p_ret
,
289 struct rb_node
**parent_ret
)
291 struct rb_root
*root
= &tree
->state
;
292 struct rb_node
**n
= &root
->rb_node
;
293 struct rb_node
*prev
= NULL
;
294 struct rb_node
*orig_prev
= NULL
;
295 struct tree_entry
*entry
;
296 struct tree_entry
*prev_entry
= NULL
;
300 entry
= rb_entry(prev
, struct tree_entry
, rb_node
);
303 if (offset
< entry
->start
)
305 else if (offset
> entry
->end
)
318 while (prev
&& offset
> prev_entry
->end
) {
319 prev
= rb_next(prev
);
320 prev_entry
= rb_entry(prev
, struct tree_entry
, rb_node
);
327 prev_entry
= rb_entry(prev
, struct tree_entry
, rb_node
);
328 while (prev
&& offset
< prev_entry
->start
) {
329 prev
= rb_prev(prev
);
330 prev_entry
= rb_entry(prev
, struct tree_entry
, rb_node
);
337 static inline struct rb_node
*
338 tree_search_for_insert(struct extent_io_tree
*tree
,
340 struct rb_node
***p_ret
,
341 struct rb_node
**parent_ret
)
343 struct rb_node
*prev
= NULL
;
346 ret
= __etree_search(tree
, offset
, &prev
, NULL
, p_ret
, parent_ret
);
352 static inline struct rb_node
*tree_search(struct extent_io_tree
*tree
,
355 return tree_search_for_insert(tree
, offset
, NULL
, NULL
);
358 static void merge_cb(struct extent_io_tree
*tree
, struct extent_state
*new,
359 struct extent_state
*other
)
361 if (tree
->ops
&& tree
->ops
->merge_extent_hook
)
362 tree
->ops
->merge_extent_hook(tree
->private_data
, new, other
);
366 * utility function to look for merge candidates inside a given range.
367 * Any extents with matching state are merged together into a single
368 * extent in the tree. Extents with EXTENT_IO in their state field
369 * are not merged because the end_io handlers need to be able to do
370 * operations on them without sleeping (or doing allocations/splits).
372 * This should be called with the tree lock held.
374 static void merge_state(struct extent_io_tree
*tree
,
375 struct extent_state
*state
)
377 struct extent_state
*other
;
378 struct rb_node
*other_node
;
380 if (state
->state
& (EXTENT_IOBITS
| EXTENT_BOUNDARY
))
383 other_node
= rb_prev(&state
->rb_node
);
385 other
= rb_entry(other_node
, struct extent_state
, rb_node
);
386 if (other
->end
== state
->start
- 1 &&
387 other
->state
== state
->state
) {
388 merge_cb(tree
, state
, other
);
389 state
->start
= other
->start
;
390 rb_erase(&other
->rb_node
, &tree
->state
);
391 RB_CLEAR_NODE(&other
->rb_node
);
392 free_extent_state(other
);
395 other_node
= rb_next(&state
->rb_node
);
397 other
= rb_entry(other_node
, struct extent_state
, rb_node
);
398 if (other
->start
== state
->end
+ 1 &&
399 other
->state
== state
->state
) {
400 merge_cb(tree
, state
, other
);
401 state
->end
= other
->end
;
402 rb_erase(&other
->rb_node
, &tree
->state
);
403 RB_CLEAR_NODE(&other
->rb_node
);
404 free_extent_state(other
);
409 static void set_state_cb(struct extent_io_tree
*tree
,
410 struct extent_state
*state
, unsigned *bits
)
412 if (tree
->ops
&& tree
->ops
->set_bit_hook
)
413 tree
->ops
->set_bit_hook(tree
->private_data
, state
, bits
);
416 static void clear_state_cb(struct extent_io_tree
*tree
,
417 struct extent_state
*state
, unsigned *bits
)
419 if (tree
->ops
&& tree
->ops
->clear_bit_hook
)
420 tree
->ops
->clear_bit_hook(tree
->private_data
, state
, bits
);
423 static void set_state_bits(struct extent_io_tree
*tree
,
424 struct extent_state
*state
, unsigned *bits
,
425 struct extent_changeset
*changeset
);
428 * insert an extent_state struct into the tree. 'bits' are set on the
429 * struct before it is inserted.
431 * This may return -EEXIST if the extent is already there, in which case the
432 * state struct is freed.
434 * The tree lock is not taken internally. This is a utility function and
435 * probably isn't what you want to call (see set/clear_extent_bit).
437 static int insert_state(struct extent_io_tree
*tree
,
438 struct extent_state
*state
, u64 start
, u64 end
,
440 struct rb_node
**parent
,
441 unsigned *bits
, struct extent_changeset
*changeset
)
443 struct rb_node
*node
;
446 WARN(1, KERN_ERR
"BTRFS: end < start %llu %llu\n",
448 state
->start
= start
;
451 set_state_bits(tree
, state
, bits
, changeset
);
453 node
= tree_insert(&tree
->state
, NULL
, end
, &state
->rb_node
, p
, parent
);
455 struct extent_state
*found
;
456 found
= rb_entry(node
, struct extent_state
, rb_node
);
457 pr_err("BTRFS: found node %llu %llu on insert of %llu %llu\n",
458 found
->start
, found
->end
, start
, end
);
461 merge_state(tree
, state
);
465 static void split_cb(struct extent_io_tree
*tree
, struct extent_state
*orig
,
468 if (tree
->ops
&& tree
->ops
->split_extent_hook
)
469 tree
->ops
->split_extent_hook(tree
->private_data
, orig
, split
);
473 * split a given extent state struct in two, inserting the preallocated
474 * struct 'prealloc' as the newly created second half. 'split' indicates an
475 * offset inside 'orig' where it should be split.
478 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
479 * are two extent state structs in the tree:
480 * prealloc: [orig->start, split - 1]
481 * orig: [ split, orig->end ]
483 * The tree locks are not taken by this function. They need to be held
486 static int split_state(struct extent_io_tree
*tree
, struct extent_state
*orig
,
487 struct extent_state
*prealloc
, u64 split
)
489 struct rb_node
*node
;
491 split_cb(tree
, orig
, split
);
493 prealloc
->start
= orig
->start
;
494 prealloc
->end
= split
- 1;
495 prealloc
->state
= orig
->state
;
498 node
= tree_insert(&tree
->state
, &orig
->rb_node
, prealloc
->end
,
499 &prealloc
->rb_node
, NULL
, NULL
);
501 free_extent_state(prealloc
);
507 static struct extent_state
*next_state(struct extent_state
*state
)
509 struct rb_node
*next
= rb_next(&state
->rb_node
);
511 return rb_entry(next
, struct extent_state
, rb_node
);
517 * utility function to clear some bits in an extent state struct.
518 * it will optionally wake up any one waiting on this state (wake == 1).
520 * If no bits are set on the state struct after clearing things, the
521 * struct is freed and removed from the tree
523 static struct extent_state
*clear_state_bit(struct extent_io_tree
*tree
,
524 struct extent_state
*state
,
525 unsigned *bits
, int wake
,
526 struct extent_changeset
*changeset
)
528 struct extent_state
*next
;
529 unsigned bits_to_clear
= *bits
& ~EXTENT_CTLBITS
;
531 if ((bits_to_clear
& EXTENT_DIRTY
) && (state
->state
& EXTENT_DIRTY
)) {
532 u64 range
= state
->end
- state
->start
+ 1;
533 WARN_ON(range
> tree
->dirty_bytes
);
534 tree
->dirty_bytes
-= range
;
536 clear_state_cb(tree
, state
, bits
);
537 add_extent_changeset(state
, bits_to_clear
, changeset
, 0);
538 state
->state
&= ~bits_to_clear
;
541 if (state
->state
== 0) {
542 next
= next_state(state
);
543 if (extent_state_in_tree(state
)) {
544 rb_erase(&state
->rb_node
, &tree
->state
);
545 RB_CLEAR_NODE(&state
->rb_node
);
546 free_extent_state(state
);
551 merge_state(tree
, state
);
552 next
= next_state(state
);
557 static struct extent_state
*
558 alloc_extent_state_atomic(struct extent_state
*prealloc
)
561 prealloc
= alloc_extent_state(GFP_ATOMIC
);
566 static void extent_io_tree_panic(struct extent_io_tree
*tree
, int err
)
568 btrfs_panic(tree_fs_info(tree
), err
,
569 "Locking error: Extent tree was modified by another thread while locked.");
573 * clear some bits on a range in the tree. This may require splitting
574 * or inserting elements in the tree, so the gfp mask is used to
575 * indicate which allocations or sleeping are allowed.
577 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
578 * the given range from the tree regardless of state (ie for truncate).
580 * the range [start, end] is inclusive.
582 * This takes the tree lock, and returns 0 on success and < 0 on error.
584 static int __clear_extent_bit(struct extent_io_tree
*tree
, u64 start
, u64 end
,
585 unsigned bits
, int wake
, int delete,
586 struct extent_state
**cached_state
,
587 gfp_t mask
, struct extent_changeset
*changeset
)
589 struct extent_state
*state
;
590 struct extent_state
*cached
;
591 struct extent_state
*prealloc
= NULL
;
592 struct rb_node
*node
;
597 btrfs_debug_check_extent_io_range(tree
, start
, end
);
599 if (bits
& EXTENT_DELALLOC
)
600 bits
|= EXTENT_NORESERVE
;
603 bits
|= ~EXTENT_CTLBITS
;
604 bits
|= EXTENT_FIRST_DELALLOC
;
606 if (bits
& (EXTENT_IOBITS
| EXTENT_BOUNDARY
))
609 if (!prealloc
&& gfpflags_allow_blocking(mask
)) {
611 * Don't care for allocation failure here because we might end
612 * up not needing the pre-allocated extent state at all, which
613 * is the case if we only have in the tree extent states that
614 * cover our input range and don't cover too any other range.
615 * If we end up needing a new extent state we allocate it later.
617 prealloc
= alloc_extent_state(mask
);
620 spin_lock(&tree
->lock
);
622 cached
= *cached_state
;
625 *cached_state
= NULL
;
629 if (cached
&& extent_state_in_tree(cached
) &&
630 cached
->start
<= start
&& cached
->end
> start
) {
632 refcount_dec(&cached
->refs
);
637 free_extent_state(cached
);
640 * this search will find the extents that end after
643 node
= tree_search(tree
, start
);
646 state
= rb_entry(node
, struct extent_state
, rb_node
);
648 if (state
->start
> end
)
650 WARN_ON(state
->end
< start
);
651 last_end
= state
->end
;
653 /* the state doesn't have the wanted bits, go ahead */
654 if (!(state
->state
& bits
)) {
655 state
= next_state(state
);
660 * | ---- desired range ---- |
662 * | ------------- state -------------- |
664 * We need to split the extent we found, and may flip
665 * bits on second half.
667 * If the extent we found extends past our range, we
668 * just split and search again. It'll get split again
669 * the next time though.
671 * If the extent we found is inside our range, we clear
672 * the desired bit on it.
675 if (state
->start
< start
) {
676 prealloc
= alloc_extent_state_atomic(prealloc
);
678 err
= split_state(tree
, state
, prealloc
, start
);
680 extent_io_tree_panic(tree
, err
);
685 if (state
->end
<= end
) {
686 state
= clear_state_bit(tree
, state
, &bits
, wake
,
693 * | ---- desired range ---- |
695 * We need to split the extent, and clear the bit
698 if (state
->start
<= end
&& state
->end
> end
) {
699 prealloc
= alloc_extent_state_atomic(prealloc
);
701 err
= split_state(tree
, state
, prealloc
, end
+ 1);
703 extent_io_tree_panic(tree
, err
);
708 clear_state_bit(tree
, prealloc
, &bits
, wake
, changeset
);
714 state
= clear_state_bit(tree
, state
, &bits
, wake
, changeset
);
716 if (last_end
== (u64
)-1)
718 start
= last_end
+ 1;
719 if (start
<= end
&& state
&& !need_resched())
725 spin_unlock(&tree
->lock
);
726 if (gfpflags_allow_blocking(mask
))
731 spin_unlock(&tree
->lock
);
733 free_extent_state(prealloc
);
739 static void wait_on_state(struct extent_io_tree
*tree
,
740 struct extent_state
*state
)
741 __releases(tree
->lock
)
742 __acquires(tree
->lock
)
745 prepare_to_wait(&state
->wq
, &wait
, TASK_UNINTERRUPTIBLE
);
746 spin_unlock(&tree
->lock
);
748 spin_lock(&tree
->lock
);
749 finish_wait(&state
->wq
, &wait
);
753 * waits for one or more bits to clear on a range in the state tree.
754 * The range [start, end] is inclusive.
755 * The tree lock is taken by this function
757 static void wait_extent_bit(struct extent_io_tree
*tree
, u64 start
, u64 end
,
760 struct extent_state
*state
;
761 struct rb_node
*node
;
763 btrfs_debug_check_extent_io_range(tree
, start
, end
);
765 spin_lock(&tree
->lock
);
769 * this search will find all the extents that end after
772 node
= tree_search(tree
, start
);
777 state
= rb_entry(node
, struct extent_state
, rb_node
);
779 if (state
->start
> end
)
782 if (state
->state
& bits
) {
783 start
= state
->start
;
784 refcount_inc(&state
->refs
);
785 wait_on_state(tree
, state
);
786 free_extent_state(state
);
789 start
= state
->end
+ 1;
794 if (!cond_resched_lock(&tree
->lock
)) {
795 node
= rb_next(node
);
800 spin_unlock(&tree
->lock
);
803 static void set_state_bits(struct extent_io_tree
*tree
,
804 struct extent_state
*state
,
805 unsigned *bits
, struct extent_changeset
*changeset
)
807 unsigned bits_to_set
= *bits
& ~EXTENT_CTLBITS
;
809 set_state_cb(tree
, state
, bits
);
810 if ((bits_to_set
& EXTENT_DIRTY
) && !(state
->state
& EXTENT_DIRTY
)) {
811 u64 range
= state
->end
- state
->start
+ 1;
812 tree
->dirty_bytes
+= range
;
814 add_extent_changeset(state
, bits_to_set
, changeset
, 1);
815 state
->state
|= bits_to_set
;
818 static void cache_state_if_flags(struct extent_state
*state
,
819 struct extent_state
**cached_ptr
,
822 if (cached_ptr
&& !(*cached_ptr
)) {
823 if (!flags
|| (state
->state
& flags
)) {
825 refcount_inc(&state
->refs
);
830 static void cache_state(struct extent_state
*state
,
831 struct extent_state
**cached_ptr
)
833 return cache_state_if_flags(state
, cached_ptr
,
834 EXTENT_IOBITS
| EXTENT_BOUNDARY
);
838 * set some bits on a range in the tree. This may require allocations or
839 * sleeping, so the gfp mask is used to indicate what is allowed.
841 * If any of the exclusive bits are set, this will fail with -EEXIST if some
842 * part of the range already has the desired bits set. The start of the
843 * existing range is returned in failed_start in this case.
845 * [start, end] is inclusive This takes the tree lock.
848 static int __must_check
849 __set_extent_bit(struct extent_io_tree
*tree
, u64 start
, u64 end
,
850 unsigned bits
, unsigned exclusive_bits
,
851 u64
*failed_start
, struct extent_state
**cached_state
,
852 gfp_t mask
, struct extent_changeset
*changeset
)
854 struct extent_state
*state
;
855 struct extent_state
*prealloc
= NULL
;
856 struct rb_node
*node
;
858 struct rb_node
*parent
;
863 btrfs_debug_check_extent_io_range(tree
, start
, end
);
865 bits
|= EXTENT_FIRST_DELALLOC
;
867 if (!prealloc
&& gfpflags_allow_blocking(mask
)) {
869 * Don't care for allocation failure here because we might end
870 * up not needing the pre-allocated extent state at all, which
871 * is the case if we only have in the tree extent states that
872 * cover our input range and don't cover too any other range.
873 * If we end up needing a new extent state we allocate it later.
875 prealloc
= alloc_extent_state(mask
);
878 spin_lock(&tree
->lock
);
879 if (cached_state
&& *cached_state
) {
880 state
= *cached_state
;
881 if (state
->start
<= start
&& state
->end
> start
&&
882 extent_state_in_tree(state
)) {
883 node
= &state
->rb_node
;
888 * this search will find all the extents that end after
891 node
= tree_search_for_insert(tree
, start
, &p
, &parent
);
893 prealloc
= alloc_extent_state_atomic(prealloc
);
895 err
= insert_state(tree
, prealloc
, start
, end
,
896 &p
, &parent
, &bits
, changeset
);
898 extent_io_tree_panic(tree
, err
);
900 cache_state(prealloc
, cached_state
);
904 state
= rb_entry(node
, struct extent_state
, rb_node
);
906 last_start
= state
->start
;
907 last_end
= state
->end
;
910 * | ---- desired range ---- |
913 * Just lock what we found and keep going
915 if (state
->start
== start
&& state
->end
<= end
) {
916 if (state
->state
& exclusive_bits
) {
917 *failed_start
= state
->start
;
922 set_state_bits(tree
, state
, &bits
, changeset
);
923 cache_state(state
, cached_state
);
924 merge_state(tree
, state
);
925 if (last_end
== (u64
)-1)
927 start
= last_end
+ 1;
928 state
= next_state(state
);
929 if (start
< end
&& state
&& state
->start
== start
&&
936 * | ---- desired range ---- |
939 * | ------------- state -------------- |
941 * We need to split the extent we found, and may flip bits on
944 * If the extent we found extends past our
945 * range, we just split and search again. It'll get split
946 * again the next time though.
948 * If the extent we found is inside our range, we set the
951 if (state
->start
< start
) {
952 if (state
->state
& exclusive_bits
) {
953 *failed_start
= start
;
958 prealloc
= alloc_extent_state_atomic(prealloc
);
960 err
= split_state(tree
, state
, prealloc
, start
);
962 extent_io_tree_panic(tree
, err
);
967 if (state
->end
<= end
) {
968 set_state_bits(tree
, state
, &bits
, changeset
);
969 cache_state(state
, cached_state
);
970 merge_state(tree
, state
);
971 if (last_end
== (u64
)-1)
973 start
= last_end
+ 1;
974 state
= next_state(state
);
975 if (start
< end
&& state
&& state
->start
== start
&&
982 * | ---- desired range ---- |
983 * | state | or | state |
985 * There's a hole, we need to insert something in it and
986 * ignore the extent we found.
988 if (state
->start
> start
) {
990 if (end
< last_start
)
993 this_end
= last_start
- 1;
995 prealloc
= alloc_extent_state_atomic(prealloc
);
999 * Avoid to free 'prealloc' if it can be merged with
1002 err
= insert_state(tree
, prealloc
, start
, this_end
,
1003 NULL
, NULL
, &bits
, changeset
);
1005 extent_io_tree_panic(tree
, err
);
1007 cache_state(prealloc
, cached_state
);
1009 start
= this_end
+ 1;
1013 * | ---- desired range ---- |
1015 * We need to split the extent, and set the bit
1018 if (state
->start
<= end
&& state
->end
> end
) {
1019 if (state
->state
& exclusive_bits
) {
1020 *failed_start
= start
;
1025 prealloc
= alloc_extent_state_atomic(prealloc
);
1027 err
= split_state(tree
, state
, prealloc
, end
+ 1);
1029 extent_io_tree_panic(tree
, err
);
1031 set_state_bits(tree
, prealloc
, &bits
, changeset
);
1032 cache_state(prealloc
, cached_state
);
1033 merge_state(tree
, prealloc
);
1041 spin_unlock(&tree
->lock
);
1042 if (gfpflags_allow_blocking(mask
))
1047 spin_unlock(&tree
->lock
);
1049 free_extent_state(prealloc
);
1055 int set_extent_bit(struct extent_io_tree
*tree
, u64 start
, u64 end
,
1056 unsigned bits
, u64
* failed_start
,
1057 struct extent_state
**cached_state
, gfp_t mask
)
1059 return __set_extent_bit(tree
, start
, end
, bits
, 0, failed_start
,
1060 cached_state
, mask
, NULL
);
1065 * convert_extent_bit - convert all bits in a given range from one bit to
1067 * @tree: the io tree to search
1068 * @start: the start offset in bytes
1069 * @end: the end offset in bytes (inclusive)
1070 * @bits: the bits to set in this range
1071 * @clear_bits: the bits to clear in this range
1072 * @cached_state: state that we're going to cache
1074 * This will go through and set bits for the given range. If any states exist
1075 * already in this range they are set with the given bit and cleared of the
1076 * clear_bits. This is only meant to be used by things that are mergeable, ie
1077 * converting from say DELALLOC to DIRTY. This is not meant to be used with
1078 * boundary bits like LOCK.
1080 * All allocations are done with GFP_NOFS.
1082 int convert_extent_bit(struct extent_io_tree
*tree
, u64 start
, u64 end
,
1083 unsigned bits
, unsigned clear_bits
,
1084 struct extent_state
**cached_state
)
1086 struct extent_state
*state
;
1087 struct extent_state
*prealloc
= NULL
;
1088 struct rb_node
*node
;
1090 struct rb_node
*parent
;
1094 bool first_iteration
= true;
1096 btrfs_debug_check_extent_io_range(tree
, start
, end
);
1101 * Best effort, don't worry if extent state allocation fails
1102 * here for the first iteration. We might have a cached state
1103 * that matches exactly the target range, in which case no
1104 * extent state allocations are needed. We'll only know this
1105 * after locking the tree.
1107 prealloc
= alloc_extent_state(GFP_NOFS
);
1108 if (!prealloc
&& !first_iteration
)
1112 spin_lock(&tree
->lock
);
1113 if (cached_state
&& *cached_state
) {
1114 state
= *cached_state
;
1115 if (state
->start
<= start
&& state
->end
> start
&&
1116 extent_state_in_tree(state
)) {
1117 node
= &state
->rb_node
;
1123 * this search will find all the extents that end after
1126 node
= tree_search_for_insert(tree
, start
, &p
, &parent
);
1128 prealloc
= alloc_extent_state_atomic(prealloc
);
1133 err
= insert_state(tree
, prealloc
, start
, end
,
1134 &p
, &parent
, &bits
, NULL
);
1136 extent_io_tree_panic(tree
, err
);
1137 cache_state(prealloc
, cached_state
);
1141 state
= rb_entry(node
, struct extent_state
, rb_node
);
1143 last_start
= state
->start
;
1144 last_end
= state
->end
;
1147 * | ---- desired range ---- |
1150 * Just lock what we found and keep going
1152 if (state
->start
== start
&& state
->end
<= end
) {
1153 set_state_bits(tree
, state
, &bits
, NULL
);
1154 cache_state(state
, cached_state
);
1155 state
= clear_state_bit(tree
, state
, &clear_bits
, 0, NULL
);
1156 if (last_end
== (u64
)-1)
1158 start
= last_end
+ 1;
1159 if (start
< end
&& state
&& state
->start
== start
&&
1166 * | ---- desired range ---- |
1169 * | ------------- state -------------- |
1171 * We need to split the extent we found, and may flip bits on
1174 * If the extent we found extends past our
1175 * range, we just split and search again. It'll get split
1176 * again the next time though.
1178 * If the extent we found is inside our range, we set the
1179 * desired bit on it.
1181 if (state
->start
< start
) {
1182 prealloc
= alloc_extent_state_atomic(prealloc
);
1187 err
= split_state(tree
, state
, prealloc
, start
);
1189 extent_io_tree_panic(tree
, err
);
1193 if (state
->end
<= end
) {
1194 set_state_bits(tree
, state
, &bits
, NULL
);
1195 cache_state(state
, cached_state
);
1196 state
= clear_state_bit(tree
, state
, &clear_bits
, 0,
1198 if (last_end
== (u64
)-1)
1200 start
= last_end
+ 1;
1201 if (start
< end
&& state
&& state
->start
== start
&&
1208 * | ---- desired range ---- |
1209 * | state | or | state |
1211 * There's a hole, we need to insert something in it and
1212 * ignore the extent we found.
1214 if (state
->start
> start
) {
1216 if (end
< last_start
)
1219 this_end
= last_start
- 1;
1221 prealloc
= alloc_extent_state_atomic(prealloc
);
1228 * Avoid to free 'prealloc' if it can be merged with
1231 err
= insert_state(tree
, prealloc
, start
, this_end
,
1232 NULL
, NULL
, &bits
, NULL
);
1234 extent_io_tree_panic(tree
, err
);
1235 cache_state(prealloc
, cached_state
);
1237 start
= this_end
+ 1;
1241 * | ---- desired range ---- |
1243 * We need to split the extent, and set the bit
1246 if (state
->start
<= end
&& state
->end
> end
) {
1247 prealloc
= alloc_extent_state_atomic(prealloc
);
1253 err
= split_state(tree
, state
, prealloc
, end
+ 1);
1255 extent_io_tree_panic(tree
, err
);
1257 set_state_bits(tree
, prealloc
, &bits
, NULL
);
1258 cache_state(prealloc
, cached_state
);
1259 clear_state_bit(tree
, prealloc
, &clear_bits
, 0, NULL
);
1267 spin_unlock(&tree
->lock
);
1269 first_iteration
= false;
1273 spin_unlock(&tree
->lock
);
1275 free_extent_state(prealloc
);
1280 /* wrappers around set/clear extent bit */
1281 int set_record_extent_bits(struct extent_io_tree
*tree
, u64 start
, u64 end
,
1282 unsigned bits
, struct extent_changeset
*changeset
)
1285 * We don't support EXTENT_LOCKED yet, as current changeset will
1286 * record any bits changed, so for EXTENT_LOCKED case, it will
1287 * either fail with -EEXIST or changeset will record the whole
1290 BUG_ON(bits
& EXTENT_LOCKED
);
1292 return __set_extent_bit(tree
, start
, end
, bits
, 0, NULL
, NULL
, GFP_NOFS
,
1296 int clear_extent_bit(struct extent_io_tree
*tree
, u64 start
, u64 end
,
1297 unsigned bits
, int wake
, int delete,
1298 struct extent_state
**cached
, gfp_t mask
)
1300 return __clear_extent_bit(tree
, start
, end
, bits
, wake
, delete,
1301 cached
, mask
, NULL
);
1304 int clear_record_extent_bits(struct extent_io_tree
*tree
, u64 start
, u64 end
,
1305 unsigned bits
, struct extent_changeset
*changeset
)
1308 * Don't support EXTENT_LOCKED case, same reason as
1309 * set_record_extent_bits().
1311 BUG_ON(bits
& EXTENT_LOCKED
);
1313 return __clear_extent_bit(tree
, start
, end
, bits
, 0, 0, NULL
, GFP_NOFS
,
1318 * either insert or lock state struct between start and end use mask to tell
1319 * us if waiting is desired.
1321 int lock_extent_bits(struct extent_io_tree
*tree
, u64 start
, u64 end
,
1322 struct extent_state
**cached_state
)
1328 err
= __set_extent_bit(tree
, start
, end
, EXTENT_LOCKED
,
1329 EXTENT_LOCKED
, &failed_start
,
1330 cached_state
, GFP_NOFS
, NULL
);
1331 if (err
== -EEXIST
) {
1332 wait_extent_bit(tree
, failed_start
, end
, EXTENT_LOCKED
);
1333 start
= failed_start
;
1336 WARN_ON(start
> end
);
1341 int try_lock_extent(struct extent_io_tree
*tree
, u64 start
, u64 end
)
1346 err
= __set_extent_bit(tree
, start
, end
, EXTENT_LOCKED
, EXTENT_LOCKED
,
1347 &failed_start
, NULL
, GFP_NOFS
, NULL
);
1348 if (err
== -EEXIST
) {
1349 if (failed_start
> start
)
1350 clear_extent_bit(tree
, start
, failed_start
- 1,
1351 EXTENT_LOCKED
, 1, 0, NULL
, GFP_NOFS
);
1357 void extent_range_clear_dirty_for_io(struct inode
*inode
, u64 start
, u64 end
)
1359 unsigned long index
= start
>> PAGE_SHIFT
;
1360 unsigned long end_index
= end
>> PAGE_SHIFT
;
1363 while (index
<= end_index
) {
1364 page
= find_get_page(inode
->i_mapping
, index
);
1365 BUG_ON(!page
); /* Pages should be in the extent_io_tree */
1366 clear_page_dirty_for_io(page
);
1372 void extent_range_redirty_for_io(struct inode
*inode
, u64 start
, u64 end
)
1374 unsigned long index
= start
>> PAGE_SHIFT
;
1375 unsigned long end_index
= end
>> PAGE_SHIFT
;
1378 while (index
<= end_index
) {
1379 page
= find_get_page(inode
->i_mapping
, index
);
1380 BUG_ON(!page
); /* Pages should be in the extent_io_tree */
1381 __set_page_dirty_nobuffers(page
);
1382 account_page_redirty(page
);
1389 * helper function to set both pages and extents in the tree writeback
1391 static void set_range_writeback(struct extent_io_tree
*tree
, u64 start
, u64 end
)
1393 tree
->ops
->set_range_writeback(tree
->private_data
, start
, end
);
1396 /* find the first state struct with 'bits' set after 'start', and
1397 * return it. tree->lock must be held. NULL will returned if
1398 * nothing was found after 'start'
1400 static struct extent_state
*
1401 find_first_extent_bit_state(struct extent_io_tree
*tree
,
1402 u64 start
, unsigned bits
)
1404 struct rb_node
*node
;
1405 struct extent_state
*state
;
1408 * this search will find all the extents that end after
1411 node
= tree_search(tree
, start
);
1416 state
= rb_entry(node
, struct extent_state
, rb_node
);
1417 if (state
->end
>= start
&& (state
->state
& bits
))
1420 node
= rb_next(node
);
1429 * find the first offset in the io tree with 'bits' set. zero is
1430 * returned if we find something, and *start_ret and *end_ret are
1431 * set to reflect the state struct that was found.
1433 * If nothing was found, 1 is returned. If found something, return 0.
1435 int find_first_extent_bit(struct extent_io_tree
*tree
, u64 start
,
1436 u64
*start_ret
, u64
*end_ret
, unsigned bits
,
1437 struct extent_state
**cached_state
)
1439 struct extent_state
*state
;
1443 spin_lock(&tree
->lock
);
1444 if (cached_state
&& *cached_state
) {
1445 state
= *cached_state
;
1446 if (state
->end
== start
- 1 && extent_state_in_tree(state
)) {
1447 n
= rb_next(&state
->rb_node
);
1449 state
= rb_entry(n
, struct extent_state
,
1451 if (state
->state
& bits
)
1455 free_extent_state(*cached_state
);
1456 *cached_state
= NULL
;
1459 free_extent_state(*cached_state
);
1460 *cached_state
= NULL
;
1463 state
= find_first_extent_bit_state(tree
, start
, bits
);
1466 cache_state_if_flags(state
, cached_state
, 0);
1467 *start_ret
= state
->start
;
1468 *end_ret
= state
->end
;
1472 spin_unlock(&tree
->lock
);
1477 * find a contiguous range of bytes in the file marked as delalloc, not
1478 * more than 'max_bytes'. start and end are used to return the range,
1480 * 1 is returned if we find something, 0 if nothing was in the tree
1482 static noinline u64
find_delalloc_range(struct extent_io_tree
*tree
,
1483 u64
*start
, u64
*end
, u64 max_bytes
,
1484 struct extent_state
**cached_state
)
1486 struct rb_node
*node
;
1487 struct extent_state
*state
;
1488 u64 cur_start
= *start
;
1490 u64 total_bytes
= 0;
1492 spin_lock(&tree
->lock
);
1495 * this search will find all the extents that end after
1498 node
= tree_search(tree
, cur_start
);
1506 state
= rb_entry(node
, struct extent_state
, rb_node
);
1507 if (found
&& (state
->start
!= cur_start
||
1508 (state
->state
& EXTENT_BOUNDARY
))) {
1511 if (!(state
->state
& EXTENT_DELALLOC
)) {
1517 *start
= state
->start
;
1518 *cached_state
= state
;
1519 refcount_inc(&state
->refs
);
1523 cur_start
= state
->end
+ 1;
1524 node
= rb_next(node
);
1525 total_bytes
+= state
->end
- state
->start
+ 1;
1526 if (total_bytes
>= max_bytes
)
1532 spin_unlock(&tree
->lock
);
1536 static int __process_pages_contig(struct address_space
*mapping
,
1537 struct page
*locked_page
,
1538 pgoff_t start_index
, pgoff_t end_index
,
1539 unsigned long page_ops
, pgoff_t
*index_ret
);
1541 static noinline
void __unlock_for_delalloc(struct inode
*inode
,
1542 struct page
*locked_page
,
1545 unsigned long index
= start
>> PAGE_SHIFT
;
1546 unsigned long end_index
= end
>> PAGE_SHIFT
;
1548 ASSERT(locked_page
);
1549 if (index
== locked_page
->index
&& end_index
== index
)
1552 __process_pages_contig(inode
->i_mapping
, locked_page
, index
, end_index
,
1556 static noinline
int lock_delalloc_pages(struct inode
*inode
,
1557 struct page
*locked_page
,
1561 unsigned long index
= delalloc_start
>> PAGE_SHIFT
;
1562 unsigned long index_ret
= index
;
1563 unsigned long end_index
= delalloc_end
>> PAGE_SHIFT
;
1566 ASSERT(locked_page
);
1567 if (index
== locked_page
->index
&& index
== end_index
)
1570 ret
= __process_pages_contig(inode
->i_mapping
, locked_page
, index
,
1571 end_index
, PAGE_LOCK
, &index_ret
);
1573 __unlock_for_delalloc(inode
, locked_page
, delalloc_start
,
1574 (u64
)index_ret
<< PAGE_SHIFT
);
1579 * find a contiguous range of bytes in the file marked as delalloc, not
1580 * more than 'max_bytes'. start and end are used to return the range,
1582 * 1 is returned if we find something, 0 if nothing was in the tree
1584 STATIC u64
find_lock_delalloc_range(struct inode
*inode
,
1585 struct extent_io_tree
*tree
,
1586 struct page
*locked_page
, u64
*start
,
1587 u64
*end
, u64 max_bytes
)
1592 struct extent_state
*cached_state
= NULL
;
1597 /* step one, find a bunch of delalloc bytes starting at start */
1598 delalloc_start
= *start
;
1600 found
= find_delalloc_range(tree
, &delalloc_start
, &delalloc_end
,
1601 max_bytes
, &cached_state
);
1602 if (!found
|| delalloc_end
<= *start
) {
1603 *start
= delalloc_start
;
1604 *end
= delalloc_end
;
1605 free_extent_state(cached_state
);
1610 * start comes from the offset of locked_page. We have to lock
1611 * pages in order, so we can't process delalloc bytes before
1614 if (delalloc_start
< *start
)
1615 delalloc_start
= *start
;
1618 * make sure to limit the number of pages we try to lock down
1620 if (delalloc_end
+ 1 - delalloc_start
> max_bytes
)
1621 delalloc_end
= delalloc_start
+ max_bytes
- 1;
1623 /* step two, lock all the pages after the page that has start */
1624 ret
= lock_delalloc_pages(inode
, locked_page
,
1625 delalloc_start
, delalloc_end
);
1626 if (ret
== -EAGAIN
) {
1627 /* some of the pages are gone, lets avoid looping by
1628 * shortening the size of the delalloc range we're searching
1630 free_extent_state(cached_state
);
1631 cached_state
= NULL
;
1633 max_bytes
= PAGE_SIZE
;
1641 BUG_ON(ret
); /* Only valid values are 0 and -EAGAIN */
1643 /* step three, lock the state bits for the whole range */
1644 lock_extent_bits(tree
, delalloc_start
, delalloc_end
, &cached_state
);
1646 /* then test to make sure it is all still delalloc */
1647 ret
= test_range_bit(tree
, delalloc_start
, delalloc_end
,
1648 EXTENT_DELALLOC
, 1, cached_state
);
1650 unlock_extent_cached(tree
, delalloc_start
, delalloc_end
,
1651 &cached_state
, GFP_NOFS
);
1652 __unlock_for_delalloc(inode
, locked_page
,
1653 delalloc_start
, delalloc_end
);
1657 free_extent_state(cached_state
);
1658 *start
= delalloc_start
;
1659 *end
= delalloc_end
;
1664 static int __process_pages_contig(struct address_space
*mapping
,
1665 struct page
*locked_page
,
1666 pgoff_t start_index
, pgoff_t end_index
,
1667 unsigned long page_ops
, pgoff_t
*index_ret
)
1669 unsigned long nr_pages
= end_index
- start_index
+ 1;
1670 unsigned long pages_locked
= 0;
1671 pgoff_t index
= start_index
;
1672 struct page
*pages
[16];
1677 if (page_ops
& PAGE_LOCK
) {
1678 ASSERT(page_ops
== PAGE_LOCK
);
1679 ASSERT(index_ret
&& *index_ret
== start_index
);
1682 if ((page_ops
& PAGE_SET_ERROR
) && nr_pages
> 0)
1683 mapping_set_error(mapping
, -EIO
);
1685 while (nr_pages
> 0) {
1686 ret
= find_get_pages_contig(mapping
, index
,
1687 min_t(unsigned long,
1688 nr_pages
, ARRAY_SIZE(pages
)), pages
);
1691 * Only if we're going to lock these pages,
1692 * can we find nothing at @index.
1694 ASSERT(page_ops
& PAGE_LOCK
);
1699 for (i
= 0; i
< ret
; i
++) {
1700 if (page_ops
& PAGE_SET_PRIVATE2
)
1701 SetPagePrivate2(pages
[i
]);
1703 if (pages
[i
] == locked_page
) {
1708 if (page_ops
& PAGE_CLEAR_DIRTY
)
1709 clear_page_dirty_for_io(pages
[i
]);
1710 if (page_ops
& PAGE_SET_WRITEBACK
)
1711 set_page_writeback(pages
[i
]);
1712 if (page_ops
& PAGE_SET_ERROR
)
1713 SetPageError(pages
[i
]);
1714 if (page_ops
& PAGE_END_WRITEBACK
)
1715 end_page_writeback(pages
[i
]);
1716 if (page_ops
& PAGE_UNLOCK
)
1717 unlock_page(pages
[i
]);
1718 if (page_ops
& PAGE_LOCK
) {
1719 lock_page(pages
[i
]);
1720 if (!PageDirty(pages
[i
]) ||
1721 pages
[i
]->mapping
!= mapping
) {
1722 unlock_page(pages
[i
]);
1736 if (err
&& index_ret
)
1737 *index_ret
= start_index
+ pages_locked
- 1;
1741 void extent_clear_unlock_delalloc(struct inode
*inode
, u64 start
, u64 end
,
1742 u64 delalloc_end
, struct page
*locked_page
,
1743 unsigned clear_bits
,
1744 unsigned long page_ops
)
1746 clear_extent_bit(&BTRFS_I(inode
)->io_tree
, start
, end
, clear_bits
, 1, 0,
1749 __process_pages_contig(inode
->i_mapping
, locked_page
,
1750 start
>> PAGE_SHIFT
, end
>> PAGE_SHIFT
,
1755 * count the number of bytes in the tree that have a given bit(s)
1756 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1757 * cached. The total number found is returned.
1759 u64
count_range_bits(struct extent_io_tree
*tree
,
1760 u64
*start
, u64 search_end
, u64 max_bytes
,
1761 unsigned bits
, int contig
)
1763 struct rb_node
*node
;
1764 struct extent_state
*state
;
1765 u64 cur_start
= *start
;
1766 u64 total_bytes
= 0;
1770 if (WARN_ON(search_end
<= cur_start
))
1773 spin_lock(&tree
->lock
);
1774 if (cur_start
== 0 && bits
== EXTENT_DIRTY
) {
1775 total_bytes
= tree
->dirty_bytes
;
1779 * this search will find all the extents that end after
1782 node
= tree_search(tree
, cur_start
);
1787 state
= rb_entry(node
, struct extent_state
, rb_node
);
1788 if (state
->start
> search_end
)
1790 if (contig
&& found
&& state
->start
> last
+ 1)
1792 if (state
->end
>= cur_start
&& (state
->state
& bits
) == bits
) {
1793 total_bytes
+= min(search_end
, state
->end
) + 1 -
1794 max(cur_start
, state
->start
);
1795 if (total_bytes
>= max_bytes
)
1798 *start
= max(cur_start
, state
->start
);
1802 } else if (contig
&& found
) {
1805 node
= rb_next(node
);
1810 spin_unlock(&tree
->lock
);
1815 * set the private field for a given byte offset in the tree. If there isn't
1816 * an extent_state there already, this does nothing.
1818 static noinline
int set_state_failrec(struct extent_io_tree
*tree
, u64 start
,
1819 struct io_failure_record
*failrec
)
1821 struct rb_node
*node
;
1822 struct extent_state
*state
;
1825 spin_lock(&tree
->lock
);
1827 * this search will find all the extents that end after
1830 node
= tree_search(tree
, start
);
1835 state
= rb_entry(node
, struct extent_state
, rb_node
);
1836 if (state
->start
!= start
) {
1840 state
->failrec
= failrec
;
1842 spin_unlock(&tree
->lock
);
1846 static noinline
int get_state_failrec(struct extent_io_tree
*tree
, u64 start
,
1847 struct io_failure_record
**failrec
)
1849 struct rb_node
*node
;
1850 struct extent_state
*state
;
1853 spin_lock(&tree
->lock
);
1855 * this search will find all the extents that end after
1858 node
= tree_search(tree
, start
);
1863 state
= rb_entry(node
, struct extent_state
, rb_node
);
1864 if (state
->start
!= start
) {
1868 *failrec
= state
->failrec
;
1870 spin_unlock(&tree
->lock
);
1875 * searches a range in the state tree for a given mask.
1876 * If 'filled' == 1, this returns 1 only if every extent in the tree
1877 * has the bits set. Otherwise, 1 is returned if any bit in the
1878 * range is found set.
1880 int test_range_bit(struct extent_io_tree
*tree
, u64 start
, u64 end
,
1881 unsigned bits
, int filled
, struct extent_state
*cached
)
1883 struct extent_state
*state
= NULL
;
1884 struct rb_node
*node
;
1887 spin_lock(&tree
->lock
);
1888 if (cached
&& extent_state_in_tree(cached
) && cached
->start
<= start
&&
1889 cached
->end
> start
)
1890 node
= &cached
->rb_node
;
1892 node
= tree_search(tree
, start
);
1893 while (node
&& start
<= end
) {
1894 state
= rb_entry(node
, struct extent_state
, rb_node
);
1896 if (filled
&& state
->start
> start
) {
1901 if (state
->start
> end
)
1904 if (state
->state
& bits
) {
1908 } else if (filled
) {
1913 if (state
->end
== (u64
)-1)
1916 start
= state
->end
+ 1;
1919 node
= rb_next(node
);
1926 spin_unlock(&tree
->lock
);
1931 * helper function to set a given page up to date if all the
1932 * extents in the tree for that page are up to date
1934 static void check_page_uptodate(struct extent_io_tree
*tree
, struct page
*page
)
1936 u64 start
= page_offset(page
);
1937 u64 end
= start
+ PAGE_SIZE
- 1;
1938 if (test_range_bit(tree
, start
, end
, EXTENT_UPTODATE
, 1, NULL
))
1939 SetPageUptodate(page
);
1942 int free_io_failure(struct extent_io_tree
*failure_tree
,
1943 struct extent_io_tree
*io_tree
,
1944 struct io_failure_record
*rec
)
1949 set_state_failrec(failure_tree
, rec
->start
, NULL
);
1950 ret
= clear_extent_bits(failure_tree
, rec
->start
,
1951 rec
->start
+ rec
->len
- 1,
1952 EXTENT_LOCKED
| EXTENT_DIRTY
);
1956 ret
= clear_extent_bits(io_tree
, rec
->start
,
1957 rec
->start
+ rec
->len
- 1,
1967 * this bypasses the standard btrfs submit functions deliberately, as
1968 * the standard behavior is to write all copies in a raid setup. here we only
1969 * want to write the one bad copy. so we do the mapping for ourselves and issue
1970 * submit_bio directly.
1971 * to avoid any synchronization issues, wait for the data after writing, which
1972 * actually prevents the read that triggered the error from finishing.
1973 * currently, there can be no more than two copies of every data bit. thus,
1974 * exactly one rewrite is required.
1976 int repair_io_failure(struct btrfs_fs_info
*fs_info
, u64 ino
, u64 start
,
1977 u64 length
, u64 logical
, struct page
*page
,
1978 unsigned int pg_offset
, int mirror_num
)
1981 struct btrfs_device
*dev
;
1984 struct btrfs_bio
*bbio
= NULL
;
1987 ASSERT(!(fs_info
->sb
->s_flags
& MS_RDONLY
));
1988 BUG_ON(!mirror_num
);
1990 bio
= btrfs_io_bio_alloc(1);
1991 bio
->bi_iter
.bi_size
= 0;
1992 map_length
= length
;
1995 * Avoid races with device replace and make sure our bbio has devices
1996 * associated to its stripes that don't go away while we are doing the
1997 * read repair operation.
1999 btrfs_bio_counter_inc_blocked(fs_info
);
2000 if (btrfs_is_parity_mirror(fs_info
, logical
, length
)) {
2002 * Note that we don't use BTRFS_MAP_WRITE because it's supposed
2003 * to update all raid stripes, but here we just want to correct
2004 * bad stripe, thus BTRFS_MAP_READ is abused to only get the bad
2005 * stripe's dev and sector.
2007 ret
= btrfs_map_block(fs_info
, BTRFS_MAP_READ
, logical
,
2008 &map_length
, &bbio
, 0);
2010 btrfs_bio_counter_dec(fs_info
);
2014 ASSERT(bbio
->mirror_num
== 1);
2016 ret
= btrfs_map_block(fs_info
, BTRFS_MAP_WRITE
, logical
,
2017 &map_length
, &bbio
, mirror_num
);
2019 btrfs_bio_counter_dec(fs_info
);
2023 BUG_ON(mirror_num
!= bbio
->mirror_num
);
2026 sector
= bbio
->stripes
[bbio
->mirror_num
- 1].physical
>> 9;
2027 bio
->bi_iter
.bi_sector
= sector
;
2028 dev
= bbio
->stripes
[bbio
->mirror_num
- 1].dev
;
2029 btrfs_put_bbio(bbio
);
2030 if (!dev
|| !dev
->bdev
|| !dev
->writeable
) {
2031 btrfs_bio_counter_dec(fs_info
);
2035 bio_set_dev(bio
, dev
->bdev
);
2036 bio
->bi_opf
= REQ_OP_WRITE
| REQ_SYNC
;
2037 bio_add_page(bio
, page
, length
, pg_offset
);
2039 if (btrfsic_submit_bio_wait(bio
)) {
2040 /* try to remap that extent elsewhere? */
2041 btrfs_bio_counter_dec(fs_info
);
2043 btrfs_dev_stat_inc_and_print(dev
, BTRFS_DEV_STAT_WRITE_ERRS
);
2047 btrfs_info_rl_in_rcu(fs_info
,
2048 "read error corrected: ino %llu off %llu (dev %s sector %llu)",
2050 rcu_str_deref(dev
->name
), sector
);
2051 btrfs_bio_counter_dec(fs_info
);
2056 int repair_eb_io_failure(struct btrfs_fs_info
*fs_info
,
2057 struct extent_buffer
*eb
, int mirror_num
)
2059 u64 start
= eb
->start
;
2060 unsigned long i
, num_pages
= num_extent_pages(eb
->start
, eb
->len
);
2063 if (sb_rdonly(fs_info
->sb
))
2066 for (i
= 0; i
< num_pages
; i
++) {
2067 struct page
*p
= eb
->pages
[i
];
2069 ret
= repair_io_failure(fs_info
, 0, start
, PAGE_SIZE
, start
, p
,
2070 start
- page_offset(p
), mirror_num
);
2080 * each time an IO finishes, we do a fast check in the IO failure tree
2081 * to see if we need to process or clean up an io_failure_record
2083 int clean_io_failure(struct btrfs_fs_info
*fs_info
,
2084 struct extent_io_tree
*failure_tree
,
2085 struct extent_io_tree
*io_tree
, u64 start
,
2086 struct page
*page
, u64 ino
, unsigned int pg_offset
)
2089 struct io_failure_record
*failrec
;
2090 struct extent_state
*state
;
2095 ret
= count_range_bits(failure_tree
, &private, (u64
)-1, 1,
2100 ret
= get_state_failrec(failure_tree
, start
, &failrec
);
2104 BUG_ON(!failrec
->this_mirror
);
2106 if (failrec
->in_validation
) {
2107 /* there was no real error, just free the record */
2108 btrfs_debug(fs_info
,
2109 "clean_io_failure: freeing dummy error at %llu",
2113 if (sb_rdonly(fs_info
->sb
))
2116 spin_lock(&io_tree
->lock
);
2117 state
= find_first_extent_bit_state(io_tree
,
2120 spin_unlock(&io_tree
->lock
);
2122 if (state
&& state
->start
<= failrec
->start
&&
2123 state
->end
>= failrec
->start
+ failrec
->len
- 1) {
2124 num_copies
= btrfs_num_copies(fs_info
, failrec
->logical
,
2126 if (num_copies
> 1) {
2127 repair_io_failure(fs_info
, ino
, start
, failrec
->len
,
2128 failrec
->logical
, page
, pg_offset
,
2129 failrec
->failed_mirror
);
2134 free_io_failure(failure_tree
, io_tree
, failrec
);
2140 * Can be called when
2141 * - hold extent lock
2142 * - under ordered extent
2143 * - the inode is freeing
2145 void btrfs_free_io_failure_record(struct btrfs_inode
*inode
, u64 start
, u64 end
)
2147 struct extent_io_tree
*failure_tree
= &inode
->io_failure_tree
;
2148 struct io_failure_record
*failrec
;
2149 struct extent_state
*state
, *next
;
2151 if (RB_EMPTY_ROOT(&failure_tree
->state
))
2154 spin_lock(&failure_tree
->lock
);
2155 state
= find_first_extent_bit_state(failure_tree
, start
, EXTENT_DIRTY
);
2157 if (state
->start
> end
)
2160 ASSERT(state
->end
<= end
);
2162 next
= next_state(state
);
2164 failrec
= state
->failrec
;
2165 free_extent_state(state
);
2170 spin_unlock(&failure_tree
->lock
);
2173 int btrfs_get_io_failure_record(struct inode
*inode
, u64 start
, u64 end
,
2174 struct io_failure_record
**failrec_ret
)
2176 struct btrfs_fs_info
*fs_info
= btrfs_sb(inode
->i_sb
);
2177 struct io_failure_record
*failrec
;
2178 struct extent_map
*em
;
2179 struct extent_io_tree
*failure_tree
= &BTRFS_I(inode
)->io_failure_tree
;
2180 struct extent_io_tree
*tree
= &BTRFS_I(inode
)->io_tree
;
2181 struct extent_map_tree
*em_tree
= &BTRFS_I(inode
)->extent_tree
;
2185 ret
= get_state_failrec(failure_tree
, start
, &failrec
);
2187 failrec
= kzalloc(sizeof(*failrec
), GFP_NOFS
);
2191 failrec
->start
= start
;
2192 failrec
->len
= end
- start
+ 1;
2193 failrec
->this_mirror
= 0;
2194 failrec
->bio_flags
= 0;
2195 failrec
->in_validation
= 0;
2197 read_lock(&em_tree
->lock
);
2198 em
= lookup_extent_mapping(em_tree
, start
, failrec
->len
);
2200 read_unlock(&em_tree
->lock
);
2205 if (em
->start
> start
|| em
->start
+ em
->len
<= start
) {
2206 free_extent_map(em
);
2209 read_unlock(&em_tree
->lock
);
2215 logical
= start
- em
->start
;
2216 logical
= em
->block_start
+ logical
;
2217 if (test_bit(EXTENT_FLAG_COMPRESSED
, &em
->flags
)) {
2218 logical
= em
->block_start
;
2219 failrec
->bio_flags
= EXTENT_BIO_COMPRESSED
;
2220 extent_set_compress_type(&failrec
->bio_flags
,
2224 btrfs_debug(fs_info
,
2225 "Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu",
2226 logical
, start
, failrec
->len
);
2228 failrec
->logical
= logical
;
2229 free_extent_map(em
);
2231 /* set the bits in the private failure tree */
2232 ret
= set_extent_bits(failure_tree
, start
, end
,
2233 EXTENT_LOCKED
| EXTENT_DIRTY
);
2235 ret
= set_state_failrec(failure_tree
, start
, failrec
);
2236 /* set the bits in the inode's tree */
2238 ret
= set_extent_bits(tree
, start
, end
, EXTENT_DAMAGED
);
2244 btrfs_debug(fs_info
,
2245 "Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d",
2246 failrec
->logical
, failrec
->start
, failrec
->len
,
2247 failrec
->in_validation
);
2249 * when data can be on disk more than twice, add to failrec here
2250 * (e.g. with a list for failed_mirror) to make
2251 * clean_io_failure() clean all those errors at once.
2255 *failrec_ret
= failrec
;
2260 bool btrfs_check_repairable(struct inode
*inode
, struct bio
*failed_bio
,
2261 struct io_failure_record
*failrec
, int failed_mirror
)
2263 struct btrfs_fs_info
*fs_info
= btrfs_sb(inode
->i_sb
);
2266 num_copies
= btrfs_num_copies(fs_info
, failrec
->logical
, failrec
->len
);
2267 if (num_copies
== 1) {
2269 * we only have a single copy of the data, so don't bother with
2270 * all the retry and error correction code that follows. no
2271 * matter what the error is, it is very likely to persist.
2273 btrfs_debug(fs_info
,
2274 "Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
2275 num_copies
, failrec
->this_mirror
, failed_mirror
);
2280 * there are two premises:
2281 * a) deliver good data to the caller
2282 * b) correct the bad sectors on disk
2284 if (failed_bio
->bi_vcnt
> 1) {
2286 * to fulfill b), we need to know the exact failing sectors, as
2287 * we don't want to rewrite any more than the failed ones. thus,
2288 * we need separate read requests for the failed bio
2290 * if the following BUG_ON triggers, our validation request got
2291 * merged. we need separate requests for our algorithm to work.
2293 BUG_ON(failrec
->in_validation
);
2294 failrec
->in_validation
= 1;
2295 failrec
->this_mirror
= failed_mirror
;
2298 * we're ready to fulfill a) and b) alongside. get a good copy
2299 * of the failed sector and if we succeed, we have setup
2300 * everything for repair_io_failure to do the rest for us.
2302 if (failrec
->in_validation
) {
2303 BUG_ON(failrec
->this_mirror
!= failed_mirror
);
2304 failrec
->in_validation
= 0;
2305 failrec
->this_mirror
= 0;
2307 failrec
->failed_mirror
= failed_mirror
;
2308 failrec
->this_mirror
++;
2309 if (failrec
->this_mirror
== failed_mirror
)
2310 failrec
->this_mirror
++;
2313 if (failrec
->this_mirror
> num_copies
) {
2314 btrfs_debug(fs_info
,
2315 "Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
2316 num_copies
, failrec
->this_mirror
, failed_mirror
);
2324 struct bio
*btrfs_create_repair_bio(struct inode
*inode
, struct bio
*failed_bio
,
2325 struct io_failure_record
*failrec
,
2326 struct page
*page
, int pg_offset
, int icsum
,
2327 bio_end_io_t
*endio_func
, void *data
)
2329 struct btrfs_fs_info
*fs_info
= btrfs_sb(inode
->i_sb
);
2331 struct btrfs_io_bio
*btrfs_failed_bio
;
2332 struct btrfs_io_bio
*btrfs_bio
;
2334 bio
= btrfs_io_bio_alloc(1);
2335 bio
->bi_end_io
= endio_func
;
2336 bio
->bi_iter
.bi_sector
= failrec
->logical
>> 9;
2337 bio_set_dev(bio
, fs_info
->fs_devices
->latest_bdev
);
2338 bio
->bi_iter
.bi_size
= 0;
2339 bio
->bi_private
= data
;
2341 btrfs_failed_bio
= btrfs_io_bio(failed_bio
);
2342 if (btrfs_failed_bio
->csum
) {
2343 u16 csum_size
= btrfs_super_csum_size(fs_info
->super_copy
);
2345 btrfs_bio
= btrfs_io_bio(bio
);
2346 btrfs_bio
->csum
= btrfs_bio
->csum_inline
;
2348 memcpy(btrfs_bio
->csum
, btrfs_failed_bio
->csum
+ icsum
,
2352 bio_add_page(bio
, page
, failrec
->len
, pg_offset
);
2358 * this is a generic handler for readpage errors (default
2359 * readpage_io_failed_hook). if other copies exist, read those and write back
2360 * good data to the failed position. does not investigate in remapping the
2361 * failed extent elsewhere, hoping the device will be smart enough to do this as
2365 static int bio_readpage_error(struct bio
*failed_bio
, u64 phy_offset
,
2366 struct page
*page
, u64 start
, u64 end
,
2369 struct io_failure_record
*failrec
;
2370 struct inode
*inode
= page
->mapping
->host
;
2371 struct extent_io_tree
*tree
= &BTRFS_I(inode
)->io_tree
;
2372 struct extent_io_tree
*failure_tree
= &BTRFS_I(inode
)->io_failure_tree
;
2375 blk_status_t status
;
2378 BUG_ON(bio_op(failed_bio
) == REQ_OP_WRITE
);
2380 ret
= btrfs_get_io_failure_record(inode
, start
, end
, &failrec
);
2384 if (!btrfs_check_repairable(inode
, failed_bio
, failrec
,
2386 free_io_failure(failure_tree
, tree
, failrec
);
2390 if (failed_bio
->bi_vcnt
> 1)
2391 read_mode
|= REQ_FAILFAST_DEV
;
2393 phy_offset
>>= inode
->i_sb
->s_blocksize_bits
;
2394 bio
= btrfs_create_repair_bio(inode
, failed_bio
, failrec
, page
,
2395 start
- page_offset(page
),
2396 (int)phy_offset
, failed_bio
->bi_end_io
,
2398 bio_set_op_attrs(bio
, REQ_OP_READ
, read_mode
);
2400 btrfs_debug(btrfs_sb(inode
->i_sb
),
2401 "Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d",
2402 read_mode
, failrec
->this_mirror
, failrec
->in_validation
);
2404 status
= tree
->ops
->submit_bio_hook(tree
->private_data
, bio
, failrec
->this_mirror
,
2405 failrec
->bio_flags
, 0);
2407 free_io_failure(failure_tree
, tree
, failrec
);
2409 ret
= blk_status_to_errno(status
);
2415 /* lots and lots of room for performance fixes in the end_bio funcs */
2417 void end_extent_writepage(struct page
*page
, int err
, u64 start
, u64 end
)
2419 int uptodate
= (err
== 0);
2420 struct extent_io_tree
*tree
;
2423 tree
= &BTRFS_I(page
->mapping
->host
)->io_tree
;
2425 if (tree
->ops
&& tree
->ops
->writepage_end_io_hook
)
2426 tree
->ops
->writepage_end_io_hook(page
, start
, end
, NULL
,
2430 ClearPageUptodate(page
);
2432 ret
= err
< 0 ? err
: -EIO
;
2433 mapping_set_error(page
->mapping
, ret
);
2438 * after a writepage IO is done, we need to:
2439 * clear the uptodate bits on error
2440 * clear the writeback bits in the extent tree for this IO
2441 * end_page_writeback if the page has no more pending IO
2443 * Scheduling is not allowed, so the extent state tree is expected
2444 * to have one and only one object corresponding to this IO.
2446 static void end_bio_extent_writepage(struct bio
*bio
)
2448 int error
= blk_status_to_errno(bio
->bi_status
);
2449 struct bio_vec
*bvec
;
2454 ASSERT(!bio_flagged(bio
, BIO_CLONED
));
2455 bio_for_each_segment_all(bvec
, bio
, i
) {
2456 struct page
*page
= bvec
->bv_page
;
2457 struct inode
*inode
= page
->mapping
->host
;
2458 struct btrfs_fs_info
*fs_info
= btrfs_sb(inode
->i_sb
);
2460 /* We always issue full-page reads, but if some block
2461 * in a page fails to read, blk_update_request() will
2462 * advance bv_offset and adjust bv_len to compensate.
2463 * Print a warning for nonzero offsets, and an error
2464 * if they don't add up to a full page. */
2465 if (bvec
->bv_offset
|| bvec
->bv_len
!= PAGE_SIZE
) {
2466 if (bvec
->bv_offset
+ bvec
->bv_len
!= PAGE_SIZE
)
2468 "partial page write in btrfs with offset %u and length %u",
2469 bvec
->bv_offset
, bvec
->bv_len
);
2472 "incomplete page write in btrfs with offset %u and length %u",
2473 bvec
->bv_offset
, bvec
->bv_len
);
2476 start
= page_offset(page
);
2477 end
= start
+ bvec
->bv_offset
+ bvec
->bv_len
- 1;
2479 end_extent_writepage(page
, error
, start
, end
);
2480 end_page_writeback(page
);
2487 endio_readpage_release_extent(struct extent_io_tree
*tree
, u64 start
, u64 len
,
2490 struct extent_state
*cached
= NULL
;
2491 u64 end
= start
+ len
- 1;
2493 if (uptodate
&& tree
->track_uptodate
)
2494 set_extent_uptodate(tree
, start
, end
, &cached
, GFP_ATOMIC
);
2495 unlock_extent_cached(tree
, start
, end
, &cached
, GFP_ATOMIC
);
2499 * after a readpage IO is done, we need to:
2500 * clear the uptodate bits on error
2501 * set the uptodate bits if things worked
2502 * set the page up to date if all extents in the tree are uptodate
2503 * clear the lock bit in the extent tree
2504 * unlock the page if there are no other extents locked for it
2506 * Scheduling is not allowed, so the extent state tree is expected
2507 * to have one and only one object corresponding to this IO.
2509 static void end_bio_extent_readpage(struct bio
*bio
)
2511 struct bio_vec
*bvec
;
2512 int uptodate
= !bio
->bi_status
;
2513 struct btrfs_io_bio
*io_bio
= btrfs_io_bio(bio
);
2514 struct extent_io_tree
*tree
, *failure_tree
;
2519 u64 extent_start
= 0;
2525 ASSERT(!bio_flagged(bio
, BIO_CLONED
));
2526 bio_for_each_segment_all(bvec
, bio
, i
) {
2527 struct page
*page
= bvec
->bv_page
;
2528 struct inode
*inode
= page
->mapping
->host
;
2529 struct btrfs_fs_info
*fs_info
= btrfs_sb(inode
->i_sb
);
2531 btrfs_debug(fs_info
,
2532 "end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
2533 (u64
)bio
->bi_iter
.bi_sector
, bio
->bi_status
,
2534 io_bio
->mirror_num
);
2535 tree
= &BTRFS_I(inode
)->io_tree
;
2536 failure_tree
= &BTRFS_I(inode
)->io_failure_tree
;
2538 /* We always issue full-page reads, but if some block
2539 * in a page fails to read, blk_update_request() will
2540 * advance bv_offset and adjust bv_len to compensate.
2541 * Print a warning for nonzero offsets, and an error
2542 * if they don't add up to a full page. */
2543 if (bvec
->bv_offset
|| bvec
->bv_len
!= PAGE_SIZE
) {
2544 if (bvec
->bv_offset
+ bvec
->bv_len
!= PAGE_SIZE
)
2546 "partial page read in btrfs with offset %u and length %u",
2547 bvec
->bv_offset
, bvec
->bv_len
);
2550 "incomplete page read in btrfs with offset %u and length %u",
2551 bvec
->bv_offset
, bvec
->bv_len
);
2554 start
= page_offset(page
);
2555 end
= start
+ bvec
->bv_offset
+ bvec
->bv_len
- 1;
2558 mirror
= io_bio
->mirror_num
;
2559 if (likely(uptodate
&& tree
->ops
)) {
2560 ret
= tree
->ops
->readpage_end_io_hook(io_bio
, offset
,
2566 clean_io_failure(BTRFS_I(inode
)->root
->fs_info
,
2567 failure_tree
, tree
, start
,
2569 btrfs_ino(BTRFS_I(inode
)), 0);
2572 if (likely(uptodate
))
2576 ret
= tree
->ops
->readpage_io_failed_hook(page
, mirror
);
2577 if (ret
== -EAGAIN
) {
2579 * Data inode's readpage_io_failed_hook() always
2582 * The generic bio_readpage_error handles errors
2583 * the following way: If possible, new read
2584 * requests are created and submitted and will
2585 * end up in end_bio_extent_readpage as well (if
2586 * we're lucky, not in the !uptodate case). In
2587 * that case it returns 0 and we just go on with
2588 * the next page in our bio. If it can't handle
2589 * the error it will return -EIO and we remain
2590 * responsible for that page.
2592 ret
= bio_readpage_error(bio
, offset
, page
,
2593 start
, end
, mirror
);
2595 uptodate
= !bio
->bi_status
;
2602 * metadata's readpage_io_failed_hook() always returns
2603 * -EIO and fixes nothing. -EIO is also returned if
2604 * data inode error could not be fixed.
2606 ASSERT(ret
== -EIO
);
2609 if (likely(uptodate
)) {
2610 loff_t i_size
= i_size_read(inode
);
2611 pgoff_t end_index
= i_size
>> PAGE_SHIFT
;
2614 /* Zero out the end if this page straddles i_size */
2615 off
= i_size
& (PAGE_SIZE
-1);
2616 if (page
->index
== end_index
&& off
)
2617 zero_user_segment(page
, off
, PAGE_SIZE
);
2618 SetPageUptodate(page
);
2620 ClearPageUptodate(page
);
2626 if (unlikely(!uptodate
)) {
2628 endio_readpage_release_extent(tree
,
2634 endio_readpage_release_extent(tree
, start
,
2635 end
- start
+ 1, 0);
2636 } else if (!extent_len
) {
2637 extent_start
= start
;
2638 extent_len
= end
+ 1 - start
;
2639 } else if (extent_start
+ extent_len
== start
) {
2640 extent_len
+= end
+ 1 - start
;
2642 endio_readpage_release_extent(tree
, extent_start
,
2643 extent_len
, uptodate
);
2644 extent_start
= start
;
2645 extent_len
= end
+ 1 - start
;
2650 endio_readpage_release_extent(tree
, extent_start
, extent_len
,
2653 io_bio
->end_io(io_bio
, blk_status_to_errno(bio
->bi_status
));
2658 * Initialize the members up to but not including 'bio'. Use after allocating a
2659 * new bio by bio_alloc_bioset as it does not initialize the bytes outside of
2660 * 'bio' because use of __GFP_ZERO is not supported.
2662 static inline void btrfs_io_bio_init(struct btrfs_io_bio
*btrfs_bio
)
2664 memset(btrfs_bio
, 0, offsetof(struct btrfs_io_bio
, bio
));
2668 * The following helpers allocate a bio. As it's backed by a bioset, it'll
2669 * never fail. We're returning a bio right now but you can call btrfs_io_bio
2670 * for the appropriate container_of magic
2672 struct bio
*btrfs_bio_alloc(struct block_device
*bdev
, u64 first_byte
)
2676 bio
= bio_alloc_bioset(GFP_NOFS
, BIO_MAX_PAGES
, btrfs_bioset
);
2677 bio_set_dev(bio
, bdev
);
2678 bio
->bi_iter
.bi_sector
= first_byte
>> 9;
2679 btrfs_io_bio_init(btrfs_io_bio(bio
));
2683 struct bio
*btrfs_bio_clone(struct bio
*bio
)
2685 struct btrfs_io_bio
*btrfs_bio
;
2688 /* Bio allocation backed by a bioset does not fail */
2689 new = bio_clone_fast(bio
, GFP_NOFS
, btrfs_bioset
);
2690 btrfs_bio
= btrfs_io_bio(new);
2691 btrfs_io_bio_init(btrfs_bio
);
2692 btrfs_bio
->iter
= bio
->bi_iter
;
2696 struct bio
*btrfs_io_bio_alloc(unsigned int nr_iovecs
)
2700 /* Bio allocation backed by a bioset does not fail */
2701 bio
= bio_alloc_bioset(GFP_NOFS
, nr_iovecs
, btrfs_bioset
);
2702 btrfs_io_bio_init(btrfs_io_bio(bio
));
2706 struct bio
*btrfs_bio_clone_partial(struct bio
*orig
, int offset
, int size
)
2709 struct btrfs_io_bio
*btrfs_bio
;
2711 /* this will never fail when it's backed by a bioset */
2712 bio
= bio_clone_fast(orig
, GFP_NOFS
, btrfs_bioset
);
2715 btrfs_bio
= btrfs_io_bio(bio
);
2716 btrfs_io_bio_init(btrfs_bio
);
2718 bio_trim(bio
, offset
>> 9, size
>> 9);
2719 btrfs_bio
->iter
= bio
->bi_iter
;
2723 static int __must_check
submit_one_bio(struct bio
*bio
, int mirror_num
,
2724 unsigned long bio_flags
)
2726 blk_status_t ret
= 0;
2727 struct bio_vec
*bvec
= bio
->bi_io_vec
+ bio
->bi_vcnt
- 1;
2728 struct page
*page
= bvec
->bv_page
;
2729 struct extent_io_tree
*tree
= bio
->bi_private
;
2732 start
= page_offset(page
) + bvec
->bv_offset
;
2734 bio
->bi_private
= NULL
;
2738 ret
= tree
->ops
->submit_bio_hook(tree
->private_data
, bio
,
2739 mirror_num
, bio_flags
, start
);
2741 btrfsic_submit_bio(bio
);
2744 return blk_status_to_errno(ret
);
2747 static int merge_bio(struct extent_io_tree
*tree
, struct page
*page
,
2748 unsigned long offset
, size_t size
, struct bio
*bio
,
2749 unsigned long bio_flags
)
2753 ret
= tree
->ops
->merge_bio_hook(page
, offset
, size
, bio
,
2760 * @opf: bio REQ_OP_* and REQ_* flags as one value
2762 static int submit_extent_page(unsigned int opf
, struct extent_io_tree
*tree
,
2763 struct writeback_control
*wbc
,
2764 struct page
*page
, u64 offset
,
2765 size_t size
, unsigned long pg_offset
,
2766 struct block_device
*bdev
,
2767 struct bio
**bio_ret
,
2768 bio_end_io_t end_io_func
,
2770 unsigned long prev_bio_flags
,
2771 unsigned long bio_flags
,
2772 bool force_bio_submit
)
2777 int old_compressed
= prev_bio_flags
& EXTENT_BIO_COMPRESSED
;
2778 size_t page_size
= min_t(size_t, size
, PAGE_SIZE
);
2779 sector_t sector
= offset
>> 9;
2781 if (bio_ret
&& *bio_ret
) {
2784 contig
= bio
->bi_iter
.bi_sector
== sector
;
2786 contig
= bio_end_sector(bio
) == sector
;
2788 if (prev_bio_flags
!= bio_flags
|| !contig
||
2790 merge_bio(tree
, page
, pg_offset
, page_size
, bio
, bio_flags
) ||
2791 bio_add_page(bio
, page
, page_size
, pg_offset
) < page_size
) {
2792 ret
= submit_one_bio(bio
, mirror_num
, prev_bio_flags
);
2800 wbc_account_io(wbc
, page
, page_size
);
2805 bio
= btrfs_bio_alloc(bdev
, offset
);
2806 bio_add_page(bio
, page
, page_size
, pg_offset
);
2807 bio
->bi_end_io
= end_io_func
;
2808 bio
->bi_private
= tree
;
2809 bio
->bi_write_hint
= page
->mapping
->host
->i_write_hint
;
2812 wbc_init_bio(wbc
, bio
);
2813 wbc_account_io(wbc
, page
, page_size
);
2819 ret
= submit_one_bio(bio
, mirror_num
, bio_flags
);
2824 static void attach_extent_buffer_page(struct extent_buffer
*eb
,
2827 if (!PagePrivate(page
)) {
2828 SetPagePrivate(page
);
2830 set_page_private(page
, (unsigned long)eb
);
2832 WARN_ON(page
->private != (unsigned long)eb
);
2836 void set_page_extent_mapped(struct page
*page
)
2838 if (!PagePrivate(page
)) {
2839 SetPagePrivate(page
);
2841 set_page_private(page
, EXTENT_PAGE_PRIVATE
);
2845 static struct extent_map
*
2846 __get_extent_map(struct inode
*inode
, struct page
*page
, size_t pg_offset
,
2847 u64 start
, u64 len
, get_extent_t
*get_extent
,
2848 struct extent_map
**em_cached
)
2850 struct extent_map
*em
;
2852 if (em_cached
&& *em_cached
) {
2854 if (extent_map_in_tree(em
) && start
>= em
->start
&&
2855 start
< extent_map_end(em
)) {
2856 refcount_inc(&em
->refs
);
2860 free_extent_map(em
);
2864 em
= get_extent(BTRFS_I(inode
), page
, pg_offset
, start
, len
, 0);
2865 if (em_cached
&& !IS_ERR_OR_NULL(em
)) {
2867 refcount_inc(&em
->refs
);
2873 * basic readpage implementation. Locked extent state structs are inserted
2874 * into the tree that are removed when the IO is done (by the end_io
2876 * XXX JDM: This needs looking at to ensure proper page locking
2877 * return 0 on success, otherwise return error
2879 static int __do_readpage(struct extent_io_tree
*tree
,
2881 get_extent_t
*get_extent
,
2882 struct extent_map
**em_cached
,
2883 struct bio
**bio
, int mirror_num
,
2884 unsigned long *bio_flags
, unsigned int read_flags
,
2887 struct inode
*inode
= page
->mapping
->host
;
2888 u64 start
= page_offset(page
);
2889 u64 page_end
= start
+ PAGE_SIZE
- 1;
2893 u64 last_byte
= i_size_read(inode
);
2896 struct extent_map
*em
;
2897 struct block_device
*bdev
;
2900 size_t pg_offset
= 0;
2902 size_t disk_io_size
;
2903 size_t blocksize
= inode
->i_sb
->s_blocksize
;
2904 unsigned long this_bio_flag
= 0;
2906 set_page_extent_mapped(page
);
2909 if (!PageUptodate(page
)) {
2910 if (cleancache_get_page(page
) == 0) {
2911 BUG_ON(blocksize
!= PAGE_SIZE
);
2912 unlock_extent(tree
, start
, end
);
2917 if (page
->index
== last_byte
>> PAGE_SHIFT
) {
2919 size_t zero_offset
= last_byte
& (PAGE_SIZE
- 1);
2922 iosize
= PAGE_SIZE
- zero_offset
;
2923 userpage
= kmap_atomic(page
);
2924 memset(userpage
+ zero_offset
, 0, iosize
);
2925 flush_dcache_page(page
);
2926 kunmap_atomic(userpage
);
2929 while (cur
<= end
) {
2930 bool force_bio_submit
= false;
2933 if (cur
>= last_byte
) {
2935 struct extent_state
*cached
= NULL
;
2937 iosize
= PAGE_SIZE
- pg_offset
;
2938 userpage
= kmap_atomic(page
);
2939 memset(userpage
+ pg_offset
, 0, iosize
);
2940 flush_dcache_page(page
);
2941 kunmap_atomic(userpage
);
2942 set_extent_uptodate(tree
, cur
, cur
+ iosize
- 1,
2944 unlock_extent_cached(tree
, cur
,
2949 em
= __get_extent_map(inode
, page
, pg_offset
, cur
,
2950 end
- cur
+ 1, get_extent
, em_cached
);
2951 if (IS_ERR_OR_NULL(em
)) {
2953 unlock_extent(tree
, cur
, end
);
2956 extent_offset
= cur
- em
->start
;
2957 BUG_ON(extent_map_end(em
) <= cur
);
2960 if (test_bit(EXTENT_FLAG_COMPRESSED
, &em
->flags
)) {
2961 this_bio_flag
|= EXTENT_BIO_COMPRESSED
;
2962 extent_set_compress_type(&this_bio_flag
,
2966 iosize
= min(extent_map_end(em
) - cur
, end
- cur
+ 1);
2967 cur_end
= min(extent_map_end(em
) - 1, end
);
2968 iosize
= ALIGN(iosize
, blocksize
);
2969 if (this_bio_flag
& EXTENT_BIO_COMPRESSED
) {
2970 disk_io_size
= em
->block_len
;
2971 offset
= em
->block_start
;
2973 offset
= em
->block_start
+ extent_offset
;
2974 disk_io_size
= iosize
;
2977 block_start
= em
->block_start
;
2978 if (test_bit(EXTENT_FLAG_PREALLOC
, &em
->flags
))
2979 block_start
= EXTENT_MAP_HOLE
;
2982 * If we have a file range that points to a compressed extent
2983 * and it's followed by a consecutive file range that points to
2984 * to the same compressed extent (possibly with a different
2985 * offset and/or length, so it either points to the whole extent
2986 * or only part of it), we must make sure we do not submit a
2987 * single bio to populate the pages for the 2 ranges because
2988 * this makes the compressed extent read zero out the pages
2989 * belonging to the 2nd range. Imagine the following scenario:
2992 * [0 - 8K] [8K - 24K]
2995 * points to extent X, points to extent X,
2996 * offset 4K, length of 8K offset 0, length 16K
2998 * [extent X, compressed length = 4K uncompressed length = 16K]
3000 * If the bio to read the compressed extent covers both ranges,
3001 * it will decompress extent X into the pages belonging to the
3002 * first range and then it will stop, zeroing out the remaining
3003 * pages that belong to the other range that points to extent X.
3004 * So here we make sure we submit 2 bios, one for the first
3005 * range and another one for the third range. Both will target
3006 * the same physical extent from disk, but we can't currently
3007 * make the compressed bio endio callback populate the pages
3008 * for both ranges because each compressed bio is tightly
3009 * coupled with a single extent map, and each range can have
3010 * an extent map with a different offset value relative to the
3011 * uncompressed data of our extent and different lengths. This
3012 * is a corner case so we prioritize correctness over
3013 * non-optimal behavior (submitting 2 bios for the same extent).
3015 if (test_bit(EXTENT_FLAG_COMPRESSED
, &em
->flags
) &&
3016 prev_em_start
&& *prev_em_start
!= (u64
)-1 &&
3017 *prev_em_start
!= em
->orig_start
)
3018 force_bio_submit
= true;
3021 *prev_em_start
= em
->orig_start
;
3023 free_extent_map(em
);
3026 /* we've found a hole, just zero and go on */
3027 if (block_start
== EXTENT_MAP_HOLE
) {
3029 struct extent_state
*cached
= NULL
;
3031 userpage
= kmap_atomic(page
);
3032 memset(userpage
+ pg_offset
, 0, iosize
);
3033 flush_dcache_page(page
);
3034 kunmap_atomic(userpage
);
3036 set_extent_uptodate(tree
, cur
, cur
+ iosize
- 1,
3038 unlock_extent_cached(tree
, cur
,
3042 pg_offset
+= iosize
;
3045 /* the get_extent function already copied into the page */
3046 if (test_range_bit(tree
, cur
, cur_end
,
3047 EXTENT_UPTODATE
, 1, NULL
)) {
3048 check_page_uptodate(tree
, page
);
3049 unlock_extent(tree
, cur
, cur
+ iosize
- 1);
3051 pg_offset
+= iosize
;
3054 /* we have an inline extent but it didn't get marked up
3055 * to date. Error out
3057 if (block_start
== EXTENT_MAP_INLINE
) {
3059 unlock_extent(tree
, cur
, cur
+ iosize
- 1);
3061 pg_offset
+= iosize
;
3065 ret
= submit_extent_page(REQ_OP_READ
| read_flags
, tree
, NULL
,
3066 page
, offset
, disk_io_size
,
3067 pg_offset
, bdev
, bio
,
3068 end_bio_extent_readpage
, mirror_num
,
3074 *bio_flags
= this_bio_flag
;
3077 unlock_extent(tree
, cur
, cur
+ iosize
- 1);
3081 pg_offset
+= iosize
;
3085 if (!PageError(page
))
3086 SetPageUptodate(page
);
3092 static inline void __do_contiguous_readpages(struct extent_io_tree
*tree
,
3093 struct page
*pages
[], int nr_pages
,
3095 get_extent_t
*get_extent
,
3096 struct extent_map
**em_cached
,
3097 struct bio
**bio
, int mirror_num
,
3098 unsigned long *bio_flags
,
3101 struct inode
*inode
;
3102 struct btrfs_ordered_extent
*ordered
;
3105 inode
= pages
[0]->mapping
->host
;
3107 lock_extent(tree
, start
, end
);
3108 ordered
= btrfs_lookup_ordered_range(BTRFS_I(inode
), start
,
3112 unlock_extent(tree
, start
, end
);
3113 btrfs_start_ordered_extent(inode
, ordered
, 1);
3114 btrfs_put_ordered_extent(ordered
);
3117 for (index
= 0; index
< nr_pages
; index
++) {
3118 __do_readpage(tree
, pages
[index
], get_extent
, em_cached
, bio
,
3119 mirror_num
, bio_flags
, 0, prev_em_start
);
3120 put_page(pages
[index
]);
3124 static void __extent_readpages(struct extent_io_tree
*tree
,
3125 struct page
*pages
[],
3126 int nr_pages
, get_extent_t
*get_extent
,
3127 struct extent_map
**em_cached
,
3128 struct bio
**bio
, int mirror_num
,
3129 unsigned long *bio_flags
,
3136 int first_index
= 0;
3138 for (index
= 0; index
< nr_pages
; index
++) {
3139 page_start
= page_offset(pages
[index
]);
3142 end
= start
+ PAGE_SIZE
- 1;
3143 first_index
= index
;
3144 } else if (end
+ 1 == page_start
) {
3147 __do_contiguous_readpages(tree
, &pages
[first_index
],
3148 index
- first_index
, start
,
3149 end
, get_extent
, em_cached
,
3150 bio
, mirror_num
, bio_flags
,
3153 end
= start
+ PAGE_SIZE
- 1;
3154 first_index
= index
;
3159 __do_contiguous_readpages(tree
, &pages
[first_index
],
3160 index
- first_index
, start
,
3161 end
, get_extent
, em_cached
, bio
,
3162 mirror_num
, bio_flags
,
3166 static int __extent_read_full_page(struct extent_io_tree
*tree
,
3168 get_extent_t
*get_extent
,
3169 struct bio
**bio
, int mirror_num
,
3170 unsigned long *bio_flags
,
3171 unsigned int read_flags
)
3173 struct inode
*inode
= page
->mapping
->host
;
3174 struct btrfs_ordered_extent
*ordered
;
3175 u64 start
= page_offset(page
);
3176 u64 end
= start
+ PAGE_SIZE
- 1;
3180 lock_extent(tree
, start
, end
);
3181 ordered
= btrfs_lookup_ordered_range(BTRFS_I(inode
), start
,
3185 unlock_extent(tree
, start
, end
);
3186 btrfs_start_ordered_extent(inode
, ordered
, 1);
3187 btrfs_put_ordered_extent(ordered
);
3190 ret
= __do_readpage(tree
, page
, get_extent
, NULL
, bio
, mirror_num
,
3191 bio_flags
, read_flags
, NULL
);
3195 int extent_read_full_page(struct extent_io_tree
*tree
, struct page
*page
,
3196 get_extent_t
*get_extent
, int mirror_num
)
3198 struct bio
*bio
= NULL
;
3199 unsigned long bio_flags
= 0;
3202 ret
= __extent_read_full_page(tree
, page
, get_extent
, &bio
, mirror_num
,
3205 ret
= submit_one_bio(bio
, mirror_num
, bio_flags
);
3209 static void update_nr_written(struct writeback_control
*wbc
,
3210 unsigned long nr_written
)
3212 wbc
->nr_to_write
-= nr_written
;
3216 * helper for __extent_writepage, doing all of the delayed allocation setup.
3218 * This returns 1 if our fill_delalloc function did all the work required
3219 * to write the page (copy into inline extent). In this case the IO has
3220 * been started and the page is already unlocked.
3222 * This returns 0 if all went well (page still locked)
3223 * This returns < 0 if there were errors (page still locked)
3225 static noinline_for_stack
int writepage_delalloc(struct inode
*inode
,
3226 struct page
*page
, struct writeback_control
*wbc
,
3227 struct extent_page_data
*epd
,
3229 unsigned long *nr_written
)
3231 struct extent_io_tree
*tree
= epd
->tree
;
3232 u64 page_end
= delalloc_start
+ PAGE_SIZE
- 1;
3234 u64 delalloc_to_write
= 0;
3235 u64 delalloc_end
= 0;
3237 int page_started
= 0;
3239 if (epd
->extent_locked
|| !tree
->ops
|| !tree
->ops
->fill_delalloc
)
3242 while (delalloc_end
< page_end
) {
3243 nr_delalloc
= find_lock_delalloc_range(inode
, tree
,
3247 BTRFS_MAX_EXTENT_SIZE
);
3248 if (nr_delalloc
== 0) {
3249 delalloc_start
= delalloc_end
+ 1;
3252 ret
= tree
->ops
->fill_delalloc(inode
, page
,
3257 /* File system has been set read-only */
3260 /* fill_delalloc should be return < 0 for error
3261 * but just in case, we use > 0 here meaning the
3262 * IO is started, so we don't want to return > 0
3263 * unless things are going well.
3265 ret
= ret
< 0 ? ret
: -EIO
;
3269 * delalloc_end is already one less than the total length, so
3270 * we don't subtract one from PAGE_SIZE
3272 delalloc_to_write
+= (delalloc_end
- delalloc_start
+
3273 PAGE_SIZE
) >> PAGE_SHIFT
;
3274 delalloc_start
= delalloc_end
+ 1;
3276 if (wbc
->nr_to_write
< delalloc_to_write
) {
3279 if (delalloc_to_write
< thresh
* 2)
3280 thresh
= delalloc_to_write
;
3281 wbc
->nr_to_write
= min_t(u64
, delalloc_to_write
,
3285 /* did the fill delalloc function already unlock and start
3290 * we've unlocked the page, so we can't update
3291 * the mapping's writeback index, just update
3294 wbc
->nr_to_write
-= *nr_written
;
3305 * helper for __extent_writepage. This calls the writepage start hooks,
3306 * and does the loop to map the page into extents and bios.
3308 * We return 1 if the IO is started and the page is unlocked,
3309 * 0 if all went well (page still locked)
3310 * < 0 if there were errors (page still locked)
3312 static noinline_for_stack
int __extent_writepage_io(struct inode
*inode
,
3314 struct writeback_control
*wbc
,
3315 struct extent_page_data
*epd
,
3317 unsigned long nr_written
,
3318 unsigned int write_flags
, int *nr_ret
)
3320 struct extent_io_tree
*tree
= epd
->tree
;
3321 u64 start
= page_offset(page
);
3322 u64 page_end
= start
+ PAGE_SIZE
- 1;
3328 struct extent_map
*em
;
3329 struct block_device
*bdev
;
3330 size_t pg_offset
= 0;
3336 if (tree
->ops
&& tree
->ops
->writepage_start_hook
) {
3337 ret
= tree
->ops
->writepage_start_hook(page
, start
,
3340 /* Fixup worker will requeue */
3342 wbc
->pages_skipped
++;
3344 redirty_page_for_writepage(wbc
, page
);
3346 update_nr_written(wbc
, nr_written
);
3353 * we don't want to touch the inode after unlocking the page,
3354 * so we update the mapping writeback index now
3356 update_nr_written(wbc
, nr_written
+ 1);
3359 if (i_size
<= start
) {
3360 if (tree
->ops
&& tree
->ops
->writepage_end_io_hook
)
3361 tree
->ops
->writepage_end_io_hook(page
, start
,
3366 blocksize
= inode
->i_sb
->s_blocksize
;
3368 while (cur
<= end
) {
3372 if (cur
>= i_size
) {
3373 if (tree
->ops
&& tree
->ops
->writepage_end_io_hook
)
3374 tree
->ops
->writepage_end_io_hook(page
, cur
,
3378 em
= epd
->get_extent(BTRFS_I(inode
), page
, pg_offset
, cur
,
3380 if (IS_ERR_OR_NULL(em
)) {
3382 ret
= PTR_ERR_OR_ZERO(em
);
3386 extent_offset
= cur
- em
->start
;
3387 em_end
= extent_map_end(em
);
3388 BUG_ON(em_end
<= cur
);
3390 iosize
= min(em_end
- cur
, end
- cur
+ 1);
3391 iosize
= ALIGN(iosize
, blocksize
);
3392 offset
= em
->block_start
+ extent_offset
;
3394 block_start
= em
->block_start
;
3395 compressed
= test_bit(EXTENT_FLAG_COMPRESSED
, &em
->flags
);
3396 free_extent_map(em
);
3400 * compressed and inline extents are written through other
3403 if (compressed
|| block_start
== EXTENT_MAP_HOLE
||
3404 block_start
== EXTENT_MAP_INLINE
) {
3406 * end_io notification does not happen here for
3407 * compressed extents
3409 if (!compressed
&& tree
->ops
&&
3410 tree
->ops
->writepage_end_io_hook
)
3411 tree
->ops
->writepage_end_io_hook(page
, cur
,
3414 else if (compressed
) {
3415 /* we don't want to end_page_writeback on
3416 * a compressed extent. this happens
3423 pg_offset
+= iosize
;
3427 set_range_writeback(tree
, cur
, cur
+ iosize
- 1);
3428 if (!PageWriteback(page
)) {
3429 btrfs_err(BTRFS_I(inode
)->root
->fs_info
,
3430 "page %lu not writeback, cur %llu end %llu",
3431 page
->index
, cur
, end
);
3434 ret
= submit_extent_page(REQ_OP_WRITE
| write_flags
, tree
, wbc
,
3435 page
, offset
, iosize
, pg_offset
,
3437 end_bio_extent_writepage
,
3441 if (PageWriteback(page
))
3442 end_page_writeback(page
);
3446 pg_offset
+= iosize
;
3455 * the writepage semantics are similar to regular writepage. extent
3456 * records are inserted to lock ranges in the tree, and as dirty areas
3457 * are found, they are marked writeback. Then the lock bits are removed
3458 * and the end_io handler clears the writeback ranges
3460 static int __extent_writepage(struct page
*page
, struct writeback_control
*wbc
,
3463 struct inode
*inode
= page
->mapping
->host
;
3464 struct extent_page_data
*epd
= data
;
3465 u64 start
= page_offset(page
);
3466 u64 page_end
= start
+ PAGE_SIZE
- 1;
3469 size_t pg_offset
= 0;
3470 loff_t i_size
= i_size_read(inode
);
3471 unsigned long end_index
= i_size
>> PAGE_SHIFT
;
3472 unsigned int write_flags
= 0;
3473 unsigned long nr_written
= 0;
3475 write_flags
= wbc_to_write_flags(wbc
);
3477 trace___extent_writepage(page
, inode
, wbc
);
3479 WARN_ON(!PageLocked(page
));
3481 ClearPageError(page
);
3483 pg_offset
= i_size
& (PAGE_SIZE
- 1);
3484 if (page
->index
> end_index
||
3485 (page
->index
== end_index
&& !pg_offset
)) {
3486 page
->mapping
->a_ops
->invalidatepage(page
, 0, PAGE_SIZE
);
3491 if (page
->index
== end_index
) {
3494 userpage
= kmap_atomic(page
);
3495 memset(userpage
+ pg_offset
, 0,
3496 PAGE_SIZE
- pg_offset
);
3497 kunmap_atomic(userpage
);
3498 flush_dcache_page(page
);
3503 set_page_extent_mapped(page
);
3505 ret
= writepage_delalloc(inode
, page
, wbc
, epd
, start
, &nr_written
);
3511 ret
= __extent_writepage_io(inode
, page
, wbc
, epd
,
3512 i_size
, nr_written
, write_flags
, &nr
);
3518 /* make sure the mapping tag for page dirty gets cleared */
3519 set_page_writeback(page
);
3520 end_page_writeback(page
);
3522 if (PageError(page
)) {
3523 ret
= ret
< 0 ? ret
: -EIO
;
3524 end_extent_writepage(page
, ret
, start
, page_end
);
3533 void wait_on_extent_buffer_writeback(struct extent_buffer
*eb
)
3535 wait_on_bit_io(&eb
->bflags
, EXTENT_BUFFER_WRITEBACK
,
3536 TASK_UNINTERRUPTIBLE
);
3539 static noinline_for_stack
int
3540 lock_extent_buffer_for_io(struct extent_buffer
*eb
,
3541 struct btrfs_fs_info
*fs_info
,
3542 struct extent_page_data
*epd
)
3544 unsigned long i
, num_pages
;
3548 if (!btrfs_try_tree_write_lock(eb
)) {
3550 flush_write_bio(epd
);
3551 btrfs_tree_lock(eb
);
3554 if (test_bit(EXTENT_BUFFER_WRITEBACK
, &eb
->bflags
)) {
3555 btrfs_tree_unlock(eb
);
3559 flush_write_bio(epd
);
3563 wait_on_extent_buffer_writeback(eb
);
3564 btrfs_tree_lock(eb
);
3565 if (!test_bit(EXTENT_BUFFER_WRITEBACK
, &eb
->bflags
))
3567 btrfs_tree_unlock(eb
);
3572 * We need to do this to prevent races in people who check if the eb is
3573 * under IO since we can end up having no IO bits set for a short period
3576 spin_lock(&eb
->refs_lock
);
3577 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY
, &eb
->bflags
)) {
3578 set_bit(EXTENT_BUFFER_WRITEBACK
, &eb
->bflags
);
3579 spin_unlock(&eb
->refs_lock
);
3580 btrfs_set_header_flag(eb
, BTRFS_HEADER_FLAG_WRITTEN
);
3581 percpu_counter_add_batch(&fs_info
->dirty_metadata_bytes
,
3583 fs_info
->dirty_metadata_batch
);
3586 spin_unlock(&eb
->refs_lock
);
3589 btrfs_tree_unlock(eb
);
3594 num_pages
= num_extent_pages(eb
->start
, eb
->len
);
3595 for (i
= 0; i
< num_pages
; i
++) {
3596 struct page
*p
= eb
->pages
[i
];
3598 if (!trylock_page(p
)) {
3600 flush_write_bio(epd
);
3610 static void end_extent_buffer_writeback(struct extent_buffer
*eb
)
3612 clear_bit(EXTENT_BUFFER_WRITEBACK
, &eb
->bflags
);
3613 smp_mb__after_atomic();
3614 wake_up_bit(&eb
->bflags
, EXTENT_BUFFER_WRITEBACK
);
3617 static void set_btree_ioerr(struct page
*page
)
3619 struct extent_buffer
*eb
= (struct extent_buffer
*)page
->private;
3622 if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR
, &eb
->bflags
))
3626 * If writeback for a btree extent that doesn't belong to a log tree
3627 * failed, increment the counter transaction->eb_write_errors.
3628 * We do this because while the transaction is running and before it's
3629 * committing (when we call filemap_fdata[write|wait]_range against
3630 * the btree inode), we might have
3631 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
3632 * returns an error or an error happens during writeback, when we're
3633 * committing the transaction we wouldn't know about it, since the pages
3634 * can be no longer dirty nor marked anymore for writeback (if a
3635 * subsequent modification to the extent buffer didn't happen before the
3636 * transaction commit), which makes filemap_fdata[write|wait]_range not
3637 * able to find the pages tagged with SetPageError at transaction
3638 * commit time. So if this happens we must abort the transaction,
3639 * otherwise we commit a super block with btree roots that point to
3640 * btree nodes/leafs whose content on disk is invalid - either garbage
3641 * or the content of some node/leaf from a past generation that got
3642 * cowed or deleted and is no longer valid.
3644 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
3645 * not be enough - we need to distinguish between log tree extents vs
3646 * non-log tree extents, and the next filemap_fdatawait_range() call
3647 * will catch and clear such errors in the mapping - and that call might
3648 * be from a log sync and not from a transaction commit. Also, checking
3649 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
3650 * not done and would not be reliable - the eb might have been released
3651 * from memory and reading it back again means that flag would not be
3652 * set (since it's a runtime flag, not persisted on disk).
3654 * Using the flags below in the btree inode also makes us achieve the
3655 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
3656 * writeback for all dirty pages and before filemap_fdatawait_range()
3657 * is called, the writeback for all dirty pages had already finished
3658 * with errors - because we were not using AS_EIO/AS_ENOSPC,
3659 * filemap_fdatawait_range() would return success, as it could not know
3660 * that writeback errors happened (the pages were no longer tagged for
3663 switch (eb
->log_index
) {
3665 set_bit(BTRFS_FS_BTREE_ERR
, &eb
->fs_info
->flags
);
3668 set_bit(BTRFS_FS_LOG1_ERR
, &eb
->fs_info
->flags
);
3671 set_bit(BTRFS_FS_LOG2_ERR
, &eb
->fs_info
->flags
);
3674 BUG(); /* unexpected, logic error */
3678 static void end_bio_extent_buffer_writepage(struct bio
*bio
)
3680 struct bio_vec
*bvec
;
3681 struct extent_buffer
*eb
;
3684 ASSERT(!bio_flagged(bio
, BIO_CLONED
));
3685 bio_for_each_segment_all(bvec
, bio
, i
) {
3686 struct page
*page
= bvec
->bv_page
;
3688 eb
= (struct extent_buffer
*)page
->private;
3690 done
= atomic_dec_and_test(&eb
->io_pages
);
3692 if (bio
->bi_status
||
3693 test_bit(EXTENT_BUFFER_WRITE_ERR
, &eb
->bflags
)) {
3694 ClearPageUptodate(page
);
3695 set_btree_ioerr(page
);
3698 end_page_writeback(page
);
3703 end_extent_buffer_writeback(eb
);
3709 static noinline_for_stack
int write_one_eb(struct extent_buffer
*eb
,
3710 struct btrfs_fs_info
*fs_info
,
3711 struct writeback_control
*wbc
,
3712 struct extent_page_data
*epd
)
3714 struct block_device
*bdev
= fs_info
->fs_devices
->latest_bdev
;
3715 struct extent_io_tree
*tree
= &BTRFS_I(fs_info
->btree_inode
)->io_tree
;
3716 u64 offset
= eb
->start
;
3718 unsigned long i
, num_pages
;
3719 unsigned long start
, end
;
3720 unsigned int write_flags
= wbc_to_write_flags(wbc
) | REQ_META
;
3723 clear_bit(EXTENT_BUFFER_WRITE_ERR
, &eb
->bflags
);
3724 num_pages
= num_extent_pages(eb
->start
, eb
->len
);
3725 atomic_set(&eb
->io_pages
, num_pages
);
3727 /* set btree blocks beyond nritems with 0 to avoid stale content. */
3728 nritems
= btrfs_header_nritems(eb
);
3729 if (btrfs_header_level(eb
) > 0) {
3730 end
= btrfs_node_key_ptr_offset(nritems
);
3732 memzero_extent_buffer(eb
, end
, eb
->len
- end
);
3736 * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
3738 start
= btrfs_item_nr_offset(nritems
);
3739 end
= BTRFS_LEAF_DATA_OFFSET
+ leaf_data_end(fs_info
, eb
);
3740 memzero_extent_buffer(eb
, start
, end
- start
);
3743 for (i
= 0; i
< num_pages
; i
++) {
3744 struct page
*p
= eb
->pages
[i
];
3746 clear_page_dirty_for_io(p
);
3747 set_page_writeback(p
);
3748 ret
= submit_extent_page(REQ_OP_WRITE
| write_flags
, tree
, wbc
,
3749 p
, offset
, PAGE_SIZE
, 0, bdev
,
3751 end_bio_extent_buffer_writepage
,
3755 if (PageWriteback(p
))
3756 end_page_writeback(p
);
3757 if (atomic_sub_and_test(num_pages
- i
, &eb
->io_pages
))
3758 end_extent_buffer_writeback(eb
);
3762 offset
+= PAGE_SIZE
;
3763 update_nr_written(wbc
, 1);
3767 if (unlikely(ret
)) {
3768 for (; i
< num_pages
; i
++) {
3769 struct page
*p
= eb
->pages
[i
];
3770 clear_page_dirty_for_io(p
);
3778 int btree_write_cache_pages(struct address_space
*mapping
,
3779 struct writeback_control
*wbc
)
3781 struct extent_io_tree
*tree
= &BTRFS_I(mapping
->host
)->io_tree
;
3782 struct btrfs_fs_info
*fs_info
= BTRFS_I(mapping
->host
)->root
->fs_info
;
3783 struct extent_buffer
*eb
, *prev_eb
= NULL
;
3784 struct extent_page_data epd
= {
3788 .sync_io
= wbc
->sync_mode
== WB_SYNC_ALL
,
3792 int nr_to_write_done
= 0;
3793 struct pagevec pvec
;
3796 pgoff_t end
; /* Inclusive */
3800 pagevec_init(&pvec
);
3801 if (wbc
->range_cyclic
) {
3802 index
= mapping
->writeback_index
; /* Start from prev offset */
3805 index
= wbc
->range_start
>> PAGE_SHIFT
;
3806 end
= wbc
->range_end
>> PAGE_SHIFT
;
3809 if (wbc
->sync_mode
== WB_SYNC_ALL
)
3810 tag
= PAGECACHE_TAG_TOWRITE
;
3812 tag
= PAGECACHE_TAG_DIRTY
;
3814 if (wbc
->sync_mode
== WB_SYNC_ALL
)
3815 tag_pages_for_writeback(mapping
, index
, end
);
3816 while (!done
&& !nr_to_write_done
&& (index
<= end
) &&
3817 (nr_pages
= pagevec_lookup_range_tag(&pvec
, mapping
, &index
, end
,
3822 for (i
= 0; i
< nr_pages
; i
++) {
3823 struct page
*page
= pvec
.pages
[i
];
3825 if (!PagePrivate(page
))
3828 spin_lock(&mapping
->private_lock
);
3829 if (!PagePrivate(page
)) {
3830 spin_unlock(&mapping
->private_lock
);
3834 eb
= (struct extent_buffer
*)page
->private;
3837 * Shouldn't happen and normally this would be a BUG_ON
3838 * but no sense in crashing the users box for something
3839 * we can survive anyway.
3842 spin_unlock(&mapping
->private_lock
);
3846 if (eb
== prev_eb
) {
3847 spin_unlock(&mapping
->private_lock
);
3851 ret
= atomic_inc_not_zero(&eb
->refs
);
3852 spin_unlock(&mapping
->private_lock
);
3857 ret
= lock_extent_buffer_for_io(eb
, fs_info
, &epd
);
3859 free_extent_buffer(eb
);
3863 ret
= write_one_eb(eb
, fs_info
, wbc
, &epd
);
3866 free_extent_buffer(eb
);
3869 free_extent_buffer(eb
);
3872 * the filesystem may choose to bump up nr_to_write.
3873 * We have to make sure to honor the new nr_to_write
3876 nr_to_write_done
= wbc
->nr_to_write
<= 0;
3878 pagevec_release(&pvec
);
3881 if (!scanned
&& !done
) {
3883 * We hit the last page and there is more work to be done: wrap
3884 * back to the start of the file
3890 flush_write_bio(&epd
);
3895 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3896 * @mapping: address space structure to write
3897 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
3898 * @writepage: function called for each page
3899 * @data: data passed to writepage function
3901 * If a page is already under I/O, write_cache_pages() skips it, even
3902 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
3903 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
3904 * and msync() need to guarantee that all the data which was dirty at the time
3905 * the call was made get new I/O started against them. If wbc->sync_mode is
3906 * WB_SYNC_ALL then we were called for data integrity and we must wait for
3907 * existing IO to complete.
3909 static int extent_write_cache_pages(struct address_space
*mapping
,
3910 struct writeback_control
*wbc
,
3911 writepage_t writepage
, void *data
,
3912 void (*flush_fn
)(void *))
3914 struct inode
*inode
= mapping
->host
;
3917 int nr_to_write_done
= 0;
3918 struct pagevec pvec
;
3921 pgoff_t end
; /* Inclusive */
3923 int range_whole
= 0;
3928 * We have to hold onto the inode so that ordered extents can do their
3929 * work when the IO finishes. The alternative to this is failing to add
3930 * an ordered extent if the igrab() fails there and that is a huge pain
3931 * to deal with, so instead just hold onto the inode throughout the
3932 * writepages operation. If it fails here we are freeing up the inode
3933 * anyway and we'd rather not waste our time writing out stuff that is
3934 * going to be truncated anyway.
3939 pagevec_init(&pvec
);
3940 if (wbc
->range_cyclic
) {
3941 index
= mapping
->writeback_index
; /* Start from prev offset */
3944 index
= wbc
->range_start
>> PAGE_SHIFT
;
3945 end
= wbc
->range_end
>> PAGE_SHIFT
;
3946 if (wbc
->range_start
== 0 && wbc
->range_end
== LLONG_MAX
)
3950 if (wbc
->sync_mode
== WB_SYNC_ALL
)
3951 tag
= PAGECACHE_TAG_TOWRITE
;
3953 tag
= PAGECACHE_TAG_DIRTY
;
3955 if (wbc
->sync_mode
== WB_SYNC_ALL
)
3956 tag_pages_for_writeback(mapping
, index
, end
);
3958 while (!done
&& !nr_to_write_done
&& (index
<= end
) &&
3959 (nr_pages
= pagevec_lookup_range_tag(&pvec
, mapping
,
3960 &index
, end
, tag
))) {
3964 for (i
= 0; i
< nr_pages
; i
++) {
3965 struct page
*page
= pvec
.pages
[i
];
3967 done_index
= page
->index
;
3969 * At this point we hold neither mapping->tree_lock nor
3970 * lock on the page itself: the page may be truncated or
3971 * invalidated (changing page->mapping to NULL), or even
3972 * swizzled back from swapper_space to tmpfs file
3975 if (!trylock_page(page
)) {
3980 if (unlikely(page
->mapping
!= mapping
)) {
3985 if (wbc
->sync_mode
!= WB_SYNC_NONE
) {
3986 if (PageWriteback(page
))
3988 wait_on_page_writeback(page
);
3991 if (PageWriteback(page
) ||
3992 !clear_page_dirty_for_io(page
)) {
3997 ret
= (*writepage
)(page
, wbc
, data
);
3999 if (unlikely(ret
== AOP_WRITEPAGE_ACTIVATE
)) {
4005 * done_index is set past this page,
4006 * so media errors will not choke
4007 * background writeout for the entire
4008 * file. This has consequences for
4009 * range_cyclic semantics (ie. it may
4010 * not be suitable for data integrity
4013 done_index
= page
->index
+ 1;
4019 * the filesystem may choose to bump up nr_to_write.
4020 * We have to make sure to honor the new nr_to_write
4023 nr_to_write_done
= wbc
->nr_to_write
<= 0;
4025 pagevec_release(&pvec
);
4028 if (!scanned
&& !done
) {
4030 * We hit the last page and there is more work to be done: wrap
4031 * back to the start of the file
4038 if (wbc
->range_cyclic
|| (wbc
->nr_to_write
> 0 && range_whole
))
4039 mapping
->writeback_index
= done_index
;
4041 btrfs_add_delayed_iput(inode
);
4045 static void flush_epd_write_bio(struct extent_page_data
*epd
)
4050 ret
= submit_one_bio(epd
->bio
, 0, 0);
4051 BUG_ON(ret
< 0); /* -ENOMEM */
4056 static noinline
void flush_write_bio(void *data
)
4058 struct extent_page_data
*epd
= data
;
4059 flush_epd_write_bio(epd
);
4062 int extent_write_full_page(struct extent_io_tree
*tree
, struct page
*page
,
4063 get_extent_t
*get_extent
,
4064 struct writeback_control
*wbc
)
4067 struct extent_page_data epd
= {
4070 .get_extent
= get_extent
,
4072 .sync_io
= wbc
->sync_mode
== WB_SYNC_ALL
,
4075 ret
= __extent_writepage(page
, wbc
, &epd
);
4077 flush_epd_write_bio(&epd
);
4081 int extent_write_locked_range(struct extent_io_tree
*tree
, struct inode
*inode
,
4082 u64 start
, u64 end
, get_extent_t
*get_extent
,
4086 struct address_space
*mapping
= inode
->i_mapping
;
4088 unsigned long nr_pages
= (end
- start
+ PAGE_SIZE
) >>
4091 struct extent_page_data epd
= {
4094 .get_extent
= get_extent
,
4096 .sync_io
= mode
== WB_SYNC_ALL
,
4098 struct writeback_control wbc_writepages
= {
4100 .nr_to_write
= nr_pages
* 2,
4101 .range_start
= start
,
4102 .range_end
= end
+ 1,
4105 while (start
<= end
) {
4106 page
= find_get_page(mapping
, start
>> PAGE_SHIFT
);
4107 if (clear_page_dirty_for_io(page
))
4108 ret
= __extent_writepage(page
, &wbc_writepages
, &epd
);
4110 if (tree
->ops
&& tree
->ops
->writepage_end_io_hook
)
4111 tree
->ops
->writepage_end_io_hook(page
, start
,
4112 start
+ PAGE_SIZE
- 1,
4120 flush_epd_write_bio(&epd
);
4124 int extent_writepages(struct extent_io_tree
*tree
,
4125 struct address_space
*mapping
,
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
,
4138 ret
= extent_write_cache_pages(mapping
, wbc
, __extent_writepage
, &epd
,
4140 flush_epd_write_bio(&epd
);
4144 int extent_readpages(struct extent_io_tree
*tree
,
4145 struct address_space
*mapping
,
4146 struct list_head
*pages
, unsigned nr_pages
,
4147 get_extent_t get_extent
)
4149 struct bio
*bio
= NULL
;
4151 unsigned long bio_flags
= 0;
4152 struct page
*pagepool
[16];
4154 struct extent_map
*em_cached
= NULL
;
4156 u64 prev_em_start
= (u64
)-1;
4158 for (page_idx
= 0; page_idx
< nr_pages
; page_idx
++) {
4159 page
= list_entry(pages
->prev
, struct page
, lru
);
4161 prefetchw(&page
->flags
);
4162 list_del(&page
->lru
);
4163 if (add_to_page_cache_lru(page
, mapping
,
4165 readahead_gfp_mask(mapping
))) {
4170 pagepool
[nr
++] = page
;
4171 if (nr
< ARRAY_SIZE(pagepool
))
4173 __extent_readpages(tree
, pagepool
, nr
, get_extent
, &em_cached
,
4174 &bio
, 0, &bio_flags
, &prev_em_start
);
4178 __extent_readpages(tree
, pagepool
, nr
, get_extent
, &em_cached
,
4179 &bio
, 0, &bio_flags
, &prev_em_start
);
4182 free_extent_map(em_cached
);
4184 BUG_ON(!list_empty(pages
));
4186 return submit_one_bio(bio
, 0, bio_flags
);
4191 * basic invalidatepage code, this waits on any locked or writeback
4192 * ranges corresponding to the page, and then deletes any extent state
4193 * records from the tree
4195 int extent_invalidatepage(struct extent_io_tree
*tree
,
4196 struct page
*page
, unsigned long offset
)
4198 struct extent_state
*cached_state
= NULL
;
4199 u64 start
= page_offset(page
);
4200 u64 end
= start
+ PAGE_SIZE
- 1;
4201 size_t blocksize
= page
->mapping
->host
->i_sb
->s_blocksize
;
4203 start
+= ALIGN(offset
, blocksize
);
4207 lock_extent_bits(tree
, start
, end
, &cached_state
);
4208 wait_on_page_writeback(page
);
4209 clear_extent_bit(tree
, start
, end
,
4210 EXTENT_LOCKED
| EXTENT_DIRTY
| EXTENT_DELALLOC
|
4211 EXTENT_DO_ACCOUNTING
,
4212 1, 1, &cached_state
, GFP_NOFS
);
4217 * a helper for releasepage, this tests for areas of the page that
4218 * are locked or under IO and drops the related state bits if it is safe
4221 static int try_release_extent_state(struct extent_map_tree
*map
,
4222 struct extent_io_tree
*tree
,
4223 struct page
*page
, gfp_t mask
)
4225 u64 start
= page_offset(page
);
4226 u64 end
= start
+ PAGE_SIZE
- 1;
4229 if (test_range_bit(tree
, start
, end
,
4230 EXTENT_IOBITS
, 0, NULL
))
4234 * at this point we can safely clear everything except the
4235 * locked bit and the nodatasum bit
4237 ret
= clear_extent_bit(tree
, start
, end
,
4238 ~(EXTENT_LOCKED
| EXTENT_NODATASUM
),
4241 /* if clear_extent_bit failed for enomem reasons,
4242 * we can't allow the release to continue.
4253 * a helper for releasepage. As long as there are no locked extents
4254 * in the range corresponding to the page, both state records and extent
4255 * map records are removed
4257 int try_release_extent_mapping(struct extent_map_tree
*map
,
4258 struct extent_io_tree
*tree
, struct page
*page
,
4261 struct extent_map
*em
;
4262 u64 start
= page_offset(page
);
4263 u64 end
= start
+ PAGE_SIZE
- 1;
4265 if (gfpflags_allow_blocking(mask
) &&
4266 page
->mapping
->host
->i_size
> SZ_16M
) {
4268 while (start
<= end
) {
4269 len
= end
- start
+ 1;
4270 write_lock(&map
->lock
);
4271 em
= lookup_extent_mapping(map
, start
, len
);
4273 write_unlock(&map
->lock
);
4276 if (test_bit(EXTENT_FLAG_PINNED
, &em
->flags
) ||
4277 em
->start
!= start
) {
4278 write_unlock(&map
->lock
);
4279 free_extent_map(em
);
4282 if (!test_range_bit(tree
, em
->start
,
4283 extent_map_end(em
) - 1,
4284 EXTENT_LOCKED
| EXTENT_WRITEBACK
,
4286 remove_extent_mapping(map
, em
);
4287 /* once for the rb tree */
4288 free_extent_map(em
);
4290 start
= extent_map_end(em
);
4291 write_unlock(&map
->lock
);
4294 free_extent_map(em
);
4297 return try_release_extent_state(map
, tree
, page
, mask
);
4301 * helper function for fiemap, which doesn't want to see any holes.
4302 * This maps until we find something past 'last'
4304 static struct extent_map
*get_extent_skip_holes(struct inode
*inode
,
4307 get_extent_t
*get_extent
)
4309 u64 sectorsize
= btrfs_inode_sectorsize(inode
);
4310 struct extent_map
*em
;
4317 len
= last
- offset
;
4320 len
= ALIGN(len
, sectorsize
);
4321 em
= get_extent(BTRFS_I(inode
), NULL
, 0, offset
, len
, 0);
4322 if (IS_ERR_OR_NULL(em
))
4325 /* if this isn't a hole return it */
4326 if (!test_bit(EXTENT_FLAG_VACANCY
, &em
->flags
) &&
4327 em
->block_start
!= EXTENT_MAP_HOLE
) {
4331 /* this is a hole, advance to the next extent */
4332 offset
= extent_map_end(em
);
4333 free_extent_map(em
);
4341 * To cache previous fiemap extent
4343 * Will be used for merging fiemap extent
4345 struct fiemap_cache
{
4354 * Helper to submit fiemap extent.
4356 * Will try to merge current fiemap extent specified by @offset, @phys,
4357 * @len and @flags with cached one.
4358 * And only when we fails to merge, cached one will be submitted as
4361 * Return value is the same as fiemap_fill_next_extent().
4363 static int emit_fiemap_extent(struct fiemap_extent_info
*fieinfo
,
4364 struct fiemap_cache
*cache
,
4365 u64 offset
, u64 phys
, u64 len
, u32 flags
)
4373 * Sanity check, extent_fiemap() should have ensured that new
4374 * fiemap extent won't overlap with cahced one.
4377 * NOTE: Physical address can overlap, due to compression
4379 if (cache
->offset
+ cache
->len
> offset
) {
4385 * Only merges fiemap extents if
4386 * 1) Their logical addresses are continuous
4388 * 2) Their physical addresses are continuous
4389 * So truly compressed (physical size smaller than logical size)
4390 * extents won't get merged with each other
4392 * 3) Share same flags except FIEMAP_EXTENT_LAST
4393 * So regular extent won't get merged with prealloc extent
4395 if (cache
->offset
+ cache
->len
== offset
&&
4396 cache
->phys
+ cache
->len
== phys
&&
4397 (cache
->flags
& ~FIEMAP_EXTENT_LAST
) ==
4398 (flags
& ~FIEMAP_EXTENT_LAST
)) {
4400 cache
->flags
|= flags
;
4401 goto try_submit_last
;
4404 /* Not mergeable, need to submit cached one */
4405 ret
= fiemap_fill_next_extent(fieinfo
, cache
->offset
, cache
->phys
,
4406 cache
->len
, cache
->flags
);
4407 cache
->cached
= false;
4411 cache
->cached
= true;
4412 cache
->offset
= offset
;
4415 cache
->flags
= flags
;
4417 if (cache
->flags
& FIEMAP_EXTENT_LAST
) {
4418 ret
= fiemap_fill_next_extent(fieinfo
, cache
->offset
,
4419 cache
->phys
, cache
->len
, cache
->flags
);
4420 cache
->cached
= false;
4426 * Emit last fiemap cache
4428 * The last fiemap cache may still be cached in the following case:
4430 * |<- Fiemap range ->|
4431 * |<------------ First extent ----------->|
4433 * In this case, the first extent range will be cached but not emitted.
4434 * So we must emit it before ending extent_fiemap().
4436 static int emit_last_fiemap_cache(struct btrfs_fs_info
*fs_info
,
4437 struct fiemap_extent_info
*fieinfo
,
4438 struct fiemap_cache
*cache
)
4445 ret
= fiemap_fill_next_extent(fieinfo
, cache
->offset
, cache
->phys
,
4446 cache
->len
, cache
->flags
);
4447 cache
->cached
= false;
4453 int extent_fiemap(struct inode
*inode
, struct fiemap_extent_info
*fieinfo
,
4454 __u64 start
, __u64 len
, get_extent_t
*get_extent
)
4458 u64 max
= start
+ len
;
4462 u64 last_for_get_extent
= 0;
4464 u64 isize
= i_size_read(inode
);
4465 struct btrfs_key found_key
;
4466 struct extent_map
*em
= NULL
;
4467 struct extent_state
*cached_state
= NULL
;
4468 struct btrfs_path
*path
;
4469 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
4470 struct fiemap_cache cache
= { 0 };
4479 path
= btrfs_alloc_path();
4482 path
->leave_spinning
= 1;
4484 start
= round_down(start
, btrfs_inode_sectorsize(inode
));
4485 len
= round_up(max
, btrfs_inode_sectorsize(inode
)) - start
;
4488 * lookup the last file extent. We're not using i_size here
4489 * because there might be preallocation past i_size
4491 ret
= btrfs_lookup_file_extent(NULL
, root
, path
,
4492 btrfs_ino(BTRFS_I(inode
)), -1, 0);
4494 btrfs_free_path(path
);
4503 btrfs_item_key_to_cpu(path
->nodes
[0], &found_key
, path
->slots
[0]);
4504 found_type
= found_key
.type
;
4506 /* No extents, but there might be delalloc bits */
4507 if (found_key
.objectid
!= btrfs_ino(BTRFS_I(inode
)) ||
4508 found_type
!= BTRFS_EXTENT_DATA_KEY
) {
4509 /* have to trust i_size as the end */
4511 last_for_get_extent
= isize
;
4514 * remember the start of the last extent. There are a
4515 * bunch of different factors that go into the length of the
4516 * extent, so its much less complex to remember where it started
4518 last
= found_key
.offset
;
4519 last_for_get_extent
= last
+ 1;
4521 btrfs_release_path(path
);
4524 * we might have some extents allocated but more delalloc past those
4525 * extents. so, we trust isize unless the start of the last extent is
4530 last_for_get_extent
= isize
;
4533 lock_extent_bits(&BTRFS_I(inode
)->io_tree
, start
, start
+ len
- 1,
4536 em
= get_extent_skip_holes(inode
, start
, last_for_get_extent
,
4546 u64 offset_in_extent
= 0;
4548 /* break if the extent we found is outside the range */
4549 if (em
->start
>= max
|| extent_map_end(em
) < off
)
4553 * get_extent may return an extent that starts before our
4554 * requested range. We have to make sure the ranges
4555 * we return to fiemap always move forward and don't
4556 * overlap, so adjust the offsets here
4558 em_start
= max(em
->start
, off
);
4561 * record the offset from the start of the extent
4562 * for adjusting the disk offset below. Only do this if the
4563 * extent isn't compressed since our in ram offset may be past
4564 * what we have actually allocated on disk.
4566 if (!test_bit(EXTENT_FLAG_COMPRESSED
, &em
->flags
))
4567 offset_in_extent
= em_start
- em
->start
;
4568 em_end
= extent_map_end(em
);
4569 em_len
= em_end
- em_start
;
4574 * bump off for our next call to get_extent
4576 off
= extent_map_end(em
);
4580 if (em
->block_start
== EXTENT_MAP_LAST_BYTE
) {
4582 flags
|= FIEMAP_EXTENT_LAST
;
4583 } else if (em
->block_start
== EXTENT_MAP_INLINE
) {
4584 flags
|= (FIEMAP_EXTENT_DATA_INLINE
|
4585 FIEMAP_EXTENT_NOT_ALIGNED
);
4586 } else if (em
->block_start
== EXTENT_MAP_DELALLOC
) {
4587 flags
|= (FIEMAP_EXTENT_DELALLOC
|
4588 FIEMAP_EXTENT_UNKNOWN
);
4589 } else if (fieinfo
->fi_extents_max
) {
4590 u64 bytenr
= em
->block_start
-
4591 (em
->start
- em
->orig_start
);
4593 disko
= em
->block_start
+ offset_in_extent
;
4596 * As btrfs supports shared space, this information
4597 * can be exported to userspace tools via
4598 * flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0
4599 * then we're just getting a count and we can skip the
4602 ret
= btrfs_check_shared(root
,
4603 btrfs_ino(BTRFS_I(inode
)),
4608 flags
|= FIEMAP_EXTENT_SHARED
;
4611 if (test_bit(EXTENT_FLAG_COMPRESSED
, &em
->flags
))
4612 flags
|= FIEMAP_EXTENT_ENCODED
;
4613 if (test_bit(EXTENT_FLAG_PREALLOC
, &em
->flags
))
4614 flags
|= FIEMAP_EXTENT_UNWRITTEN
;
4616 free_extent_map(em
);
4618 if ((em_start
>= last
) || em_len
== (u64
)-1 ||
4619 (last
== (u64
)-1 && isize
<= em_end
)) {
4620 flags
|= FIEMAP_EXTENT_LAST
;
4624 /* now scan forward to see if this is really the last extent. */
4625 em
= get_extent_skip_holes(inode
, off
, last_for_get_extent
,
4632 flags
|= FIEMAP_EXTENT_LAST
;
4635 ret
= emit_fiemap_extent(fieinfo
, &cache
, em_start
, disko
,
4645 ret
= emit_last_fiemap_cache(root
->fs_info
, fieinfo
, &cache
);
4646 free_extent_map(em
);
4648 btrfs_free_path(path
);
4649 unlock_extent_cached(&BTRFS_I(inode
)->io_tree
, start
, start
+ len
- 1,
4650 &cached_state
, GFP_NOFS
);
4654 static void __free_extent_buffer(struct extent_buffer
*eb
)
4656 btrfs_leak_debug_del(&eb
->leak_list
);
4657 kmem_cache_free(extent_buffer_cache
, eb
);
4660 int extent_buffer_under_io(struct extent_buffer
*eb
)
4662 return (atomic_read(&eb
->io_pages
) ||
4663 test_bit(EXTENT_BUFFER_WRITEBACK
, &eb
->bflags
) ||
4664 test_bit(EXTENT_BUFFER_DIRTY
, &eb
->bflags
));
4668 * Helper for releasing extent buffer page.
4670 static void btrfs_release_extent_buffer_page(struct extent_buffer
*eb
)
4672 unsigned long index
;
4674 int mapped
= !test_bit(EXTENT_BUFFER_DUMMY
, &eb
->bflags
);
4676 BUG_ON(extent_buffer_under_io(eb
));
4678 index
= num_extent_pages(eb
->start
, eb
->len
);
4684 page
= eb
->pages
[index
];
4688 spin_lock(&page
->mapping
->private_lock
);
4690 * We do this since we'll remove the pages after we've
4691 * removed the eb from the radix tree, so we could race
4692 * and have this page now attached to the new eb. So
4693 * only clear page_private if it's still connected to
4696 if (PagePrivate(page
) &&
4697 page
->private == (unsigned long)eb
) {
4698 BUG_ON(test_bit(EXTENT_BUFFER_DIRTY
, &eb
->bflags
));
4699 BUG_ON(PageDirty(page
));
4700 BUG_ON(PageWriteback(page
));
4702 * We need to make sure we haven't be attached
4705 ClearPagePrivate(page
);
4706 set_page_private(page
, 0);
4707 /* One for the page private */
4712 spin_unlock(&page
->mapping
->private_lock
);
4714 /* One for when we allocated the page */
4716 } while (index
!= 0);
4720 * Helper for releasing the extent buffer.
4722 static inline void btrfs_release_extent_buffer(struct extent_buffer
*eb
)
4724 btrfs_release_extent_buffer_page(eb
);
4725 __free_extent_buffer(eb
);
4728 static struct extent_buffer
*
4729 __alloc_extent_buffer(struct btrfs_fs_info
*fs_info
, u64 start
,
4732 struct extent_buffer
*eb
= NULL
;
4734 eb
= kmem_cache_zalloc(extent_buffer_cache
, GFP_NOFS
|__GFP_NOFAIL
);
4737 eb
->fs_info
= fs_info
;
4739 rwlock_init(&eb
->lock
);
4740 atomic_set(&eb
->write_locks
, 0);
4741 atomic_set(&eb
->read_locks
, 0);
4742 atomic_set(&eb
->blocking_readers
, 0);
4743 atomic_set(&eb
->blocking_writers
, 0);
4744 atomic_set(&eb
->spinning_readers
, 0);
4745 atomic_set(&eb
->spinning_writers
, 0);
4746 eb
->lock_nested
= 0;
4747 init_waitqueue_head(&eb
->write_lock_wq
);
4748 init_waitqueue_head(&eb
->read_lock_wq
);
4750 btrfs_leak_debug_add(&eb
->leak_list
, &buffers
);
4752 spin_lock_init(&eb
->refs_lock
);
4753 atomic_set(&eb
->refs
, 1);
4754 atomic_set(&eb
->io_pages
, 0);
4757 * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
4759 BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
4760 > MAX_INLINE_EXTENT_BUFFER_SIZE
);
4761 BUG_ON(len
> MAX_INLINE_EXTENT_BUFFER_SIZE
);
4766 struct extent_buffer
*btrfs_clone_extent_buffer(struct extent_buffer
*src
)
4770 struct extent_buffer
*new;
4771 unsigned long num_pages
= num_extent_pages(src
->start
, src
->len
);
4773 new = __alloc_extent_buffer(src
->fs_info
, src
->start
, src
->len
);
4777 for (i
= 0; i
< num_pages
; i
++) {
4778 p
= alloc_page(GFP_NOFS
);
4780 btrfs_release_extent_buffer(new);
4783 attach_extent_buffer_page(new, p
);
4784 WARN_ON(PageDirty(p
));
4787 copy_page(page_address(p
), page_address(src
->pages
[i
]));
4790 set_bit(EXTENT_BUFFER_UPTODATE
, &new->bflags
);
4791 set_bit(EXTENT_BUFFER_DUMMY
, &new->bflags
);
4796 struct extent_buffer
*__alloc_dummy_extent_buffer(struct btrfs_fs_info
*fs_info
,
4797 u64 start
, unsigned long len
)
4799 struct extent_buffer
*eb
;
4800 unsigned long num_pages
;
4803 num_pages
= num_extent_pages(start
, len
);
4805 eb
= __alloc_extent_buffer(fs_info
, start
, len
);
4809 for (i
= 0; i
< num_pages
; i
++) {
4810 eb
->pages
[i
] = alloc_page(GFP_NOFS
);
4814 set_extent_buffer_uptodate(eb
);
4815 btrfs_set_header_nritems(eb
, 0);
4816 set_bit(EXTENT_BUFFER_DUMMY
, &eb
->bflags
);
4821 __free_page(eb
->pages
[i
- 1]);
4822 __free_extent_buffer(eb
);
4826 struct extent_buffer
*alloc_dummy_extent_buffer(struct btrfs_fs_info
*fs_info
,
4829 return __alloc_dummy_extent_buffer(fs_info
, start
, fs_info
->nodesize
);
4832 static void check_buffer_tree_ref(struct extent_buffer
*eb
)
4835 /* the ref bit is tricky. We have to make sure it is set
4836 * if we have the buffer dirty. Otherwise the
4837 * code to free a buffer can end up dropping a dirty
4840 * Once the ref bit is set, it won't go away while the
4841 * buffer is dirty or in writeback, and it also won't
4842 * go away while we have the reference count on the
4845 * We can't just set the ref bit without bumping the
4846 * ref on the eb because free_extent_buffer might
4847 * see the ref bit and try to clear it. If this happens
4848 * free_extent_buffer might end up dropping our original
4849 * ref by mistake and freeing the page before we are able
4850 * to add one more ref.
4852 * So bump the ref count first, then set the bit. If someone
4853 * beat us to it, drop the ref we added.
4855 refs
= atomic_read(&eb
->refs
);
4856 if (refs
>= 2 && test_bit(EXTENT_BUFFER_TREE_REF
, &eb
->bflags
))
4859 spin_lock(&eb
->refs_lock
);
4860 if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF
, &eb
->bflags
))
4861 atomic_inc(&eb
->refs
);
4862 spin_unlock(&eb
->refs_lock
);
4865 static void mark_extent_buffer_accessed(struct extent_buffer
*eb
,
4866 struct page
*accessed
)
4868 unsigned long num_pages
, i
;
4870 check_buffer_tree_ref(eb
);
4872 num_pages
= num_extent_pages(eb
->start
, eb
->len
);
4873 for (i
= 0; i
< num_pages
; i
++) {
4874 struct page
*p
= eb
->pages
[i
];
4877 mark_page_accessed(p
);
4881 struct extent_buffer
*find_extent_buffer(struct btrfs_fs_info
*fs_info
,
4884 struct extent_buffer
*eb
;
4887 eb
= radix_tree_lookup(&fs_info
->buffer_radix
,
4888 start
>> PAGE_SHIFT
);
4889 if (eb
&& atomic_inc_not_zero(&eb
->refs
)) {
4892 * Lock our eb's refs_lock to avoid races with
4893 * free_extent_buffer. When we get our eb it might be flagged
4894 * with EXTENT_BUFFER_STALE and another task running
4895 * free_extent_buffer might have seen that flag set,
4896 * eb->refs == 2, that the buffer isn't under IO (dirty and
4897 * writeback flags not set) and it's still in the tree (flag
4898 * EXTENT_BUFFER_TREE_REF set), therefore being in the process
4899 * of decrementing the extent buffer's reference count twice.
4900 * So here we could race and increment the eb's reference count,
4901 * clear its stale flag, mark it as dirty and drop our reference
4902 * before the other task finishes executing free_extent_buffer,
4903 * which would later result in an attempt to free an extent
4904 * buffer that is dirty.
4906 if (test_bit(EXTENT_BUFFER_STALE
, &eb
->bflags
)) {
4907 spin_lock(&eb
->refs_lock
);
4908 spin_unlock(&eb
->refs_lock
);
4910 mark_extent_buffer_accessed(eb
, NULL
);
4918 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4919 struct extent_buffer
*alloc_test_extent_buffer(struct btrfs_fs_info
*fs_info
,
4922 struct extent_buffer
*eb
, *exists
= NULL
;
4925 eb
= find_extent_buffer(fs_info
, start
);
4928 eb
= alloc_dummy_extent_buffer(fs_info
, start
);
4931 eb
->fs_info
= fs_info
;
4933 ret
= radix_tree_preload(GFP_NOFS
);
4936 spin_lock(&fs_info
->buffer_lock
);
4937 ret
= radix_tree_insert(&fs_info
->buffer_radix
,
4938 start
>> PAGE_SHIFT
, eb
);
4939 spin_unlock(&fs_info
->buffer_lock
);
4940 radix_tree_preload_end();
4941 if (ret
== -EEXIST
) {
4942 exists
= find_extent_buffer(fs_info
, start
);
4948 check_buffer_tree_ref(eb
);
4949 set_bit(EXTENT_BUFFER_IN_TREE
, &eb
->bflags
);
4952 * We will free dummy extent buffer's if they come into
4953 * free_extent_buffer with a ref count of 2, but if we are using this we
4954 * want the buffers to stay in memory until we're done with them, so
4955 * bump the ref count again.
4957 atomic_inc(&eb
->refs
);
4960 btrfs_release_extent_buffer(eb
);
4965 struct extent_buffer
*alloc_extent_buffer(struct btrfs_fs_info
*fs_info
,
4968 unsigned long len
= fs_info
->nodesize
;
4969 unsigned long num_pages
= num_extent_pages(start
, len
);
4971 unsigned long index
= start
>> PAGE_SHIFT
;
4972 struct extent_buffer
*eb
;
4973 struct extent_buffer
*exists
= NULL
;
4975 struct address_space
*mapping
= fs_info
->btree_inode
->i_mapping
;
4979 if (!IS_ALIGNED(start
, fs_info
->sectorsize
)) {
4980 btrfs_err(fs_info
, "bad tree block start %llu", start
);
4981 return ERR_PTR(-EINVAL
);
4984 eb
= find_extent_buffer(fs_info
, start
);
4988 eb
= __alloc_extent_buffer(fs_info
, start
, len
);
4990 return ERR_PTR(-ENOMEM
);
4992 for (i
= 0; i
< num_pages
; i
++, index
++) {
4993 p
= find_or_create_page(mapping
, index
, GFP_NOFS
|__GFP_NOFAIL
);
4995 exists
= ERR_PTR(-ENOMEM
);
4999 spin_lock(&mapping
->private_lock
);
5000 if (PagePrivate(p
)) {
5002 * We could have already allocated an eb for this page
5003 * and attached one so lets see if we can get a ref on
5004 * the existing eb, and if we can we know it's good and
5005 * we can just return that one, else we know we can just
5006 * overwrite page->private.
5008 exists
= (struct extent_buffer
*)p
->private;
5009 if (atomic_inc_not_zero(&exists
->refs
)) {
5010 spin_unlock(&mapping
->private_lock
);
5013 mark_extent_buffer_accessed(exists
, p
);
5019 * Do this so attach doesn't complain and we need to
5020 * drop the ref the old guy had.
5022 ClearPagePrivate(p
);
5023 WARN_ON(PageDirty(p
));
5026 attach_extent_buffer_page(eb
, p
);
5027 spin_unlock(&mapping
->private_lock
);
5028 WARN_ON(PageDirty(p
));
5030 if (!PageUptodate(p
))
5034 * see below about how we avoid a nasty race with release page
5035 * and why we unlock later
5039 set_bit(EXTENT_BUFFER_UPTODATE
, &eb
->bflags
);
5041 ret
= radix_tree_preload(GFP_NOFS
);
5043 exists
= ERR_PTR(ret
);
5047 spin_lock(&fs_info
->buffer_lock
);
5048 ret
= radix_tree_insert(&fs_info
->buffer_radix
,
5049 start
>> PAGE_SHIFT
, eb
);
5050 spin_unlock(&fs_info
->buffer_lock
);
5051 radix_tree_preload_end();
5052 if (ret
== -EEXIST
) {
5053 exists
= find_extent_buffer(fs_info
, start
);
5059 /* add one reference for the tree */
5060 check_buffer_tree_ref(eb
);
5061 set_bit(EXTENT_BUFFER_IN_TREE
, &eb
->bflags
);
5064 * there is a race where release page may have
5065 * tried to find this extent buffer in the radix
5066 * but failed. It will tell the VM it is safe to
5067 * reclaim the, and it will clear the page private bit.
5068 * We must make sure to set the page private bit properly
5069 * after the extent buffer is in the radix tree so
5070 * it doesn't get lost
5072 SetPageChecked(eb
->pages
[0]);
5073 for (i
= 1; i
< num_pages
; i
++) {
5075 ClearPageChecked(p
);
5078 unlock_page(eb
->pages
[0]);
5082 WARN_ON(!atomic_dec_and_test(&eb
->refs
));
5083 for (i
= 0; i
< num_pages
; i
++) {
5085 unlock_page(eb
->pages
[i
]);
5088 btrfs_release_extent_buffer(eb
);
5092 static inline void btrfs_release_extent_buffer_rcu(struct rcu_head
*head
)
5094 struct extent_buffer
*eb
=
5095 container_of(head
, struct extent_buffer
, rcu_head
);
5097 __free_extent_buffer(eb
);
5100 /* Expects to have eb->eb_lock already held */
5101 static int release_extent_buffer(struct extent_buffer
*eb
)
5103 WARN_ON(atomic_read(&eb
->refs
) == 0);
5104 if (atomic_dec_and_test(&eb
->refs
)) {
5105 if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE
, &eb
->bflags
)) {
5106 struct btrfs_fs_info
*fs_info
= eb
->fs_info
;
5108 spin_unlock(&eb
->refs_lock
);
5110 spin_lock(&fs_info
->buffer_lock
);
5111 radix_tree_delete(&fs_info
->buffer_radix
,
5112 eb
->start
>> PAGE_SHIFT
);
5113 spin_unlock(&fs_info
->buffer_lock
);
5115 spin_unlock(&eb
->refs_lock
);
5118 /* Should be safe to release our pages at this point */
5119 btrfs_release_extent_buffer_page(eb
);
5120 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5121 if (unlikely(test_bit(EXTENT_BUFFER_DUMMY
, &eb
->bflags
))) {
5122 __free_extent_buffer(eb
);
5126 call_rcu(&eb
->rcu_head
, btrfs_release_extent_buffer_rcu
);
5129 spin_unlock(&eb
->refs_lock
);
5134 void free_extent_buffer(struct extent_buffer
*eb
)
5142 refs
= atomic_read(&eb
->refs
);
5145 old
= atomic_cmpxchg(&eb
->refs
, refs
, refs
- 1);
5150 spin_lock(&eb
->refs_lock
);
5151 if (atomic_read(&eb
->refs
) == 2 &&
5152 test_bit(EXTENT_BUFFER_DUMMY
, &eb
->bflags
))
5153 atomic_dec(&eb
->refs
);
5155 if (atomic_read(&eb
->refs
) == 2 &&
5156 test_bit(EXTENT_BUFFER_STALE
, &eb
->bflags
) &&
5157 !extent_buffer_under_io(eb
) &&
5158 test_and_clear_bit(EXTENT_BUFFER_TREE_REF
, &eb
->bflags
))
5159 atomic_dec(&eb
->refs
);
5162 * I know this is terrible, but it's temporary until we stop tracking
5163 * the uptodate bits and such for the extent buffers.
5165 release_extent_buffer(eb
);
5168 void free_extent_buffer_stale(struct extent_buffer
*eb
)
5173 spin_lock(&eb
->refs_lock
);
5174 set_bit(EXTENT_BUFFER_STALE
, &eb
->bflags
);
5176 if (atomic_read(&eb
->refs
) == 2 && !extent_buffer_under_io(eb
) &&
5177 test_and_clear_bit(EXTENT_BUFFER_TREE_REF
, &eb
->bflags
))
5178 atomic_dec(&eb
->refs
);
5179 release_extent_buffer(eb
);
5182 void clear_extent_buffer_dirty(struct extent_buffer
*eb
)
5185 unsigned long num_pages
;
5188 num_pages
= num_extent_pages(eb
->start
, eb
->len
);
5190 for (i
= 0; i
< num_pages
; i
++) {
5191 page
= eb
->pages
[i
];
5192 if (!PageDirty(page
))
5196 WARN_ON(!PagePrivate(page
));
5198 clear_page_dirty_for_io(page
);
5199 spin_lock_irq(&page
->mapping
->tree_lock
);
5200 if (!PageDirty(page
)) {
5201 radix_tree_tag_clear(&page
->mapping
->page_tree
,
5203 PAGECACHE_TAG_DIRTY
);
5205 spin_unlock_irq(&page
->mapping
->tree_lock
);
5206 ClearPageError(page
);
5209 WARN_ON(atomic_read(&eb
->refs
) == 0);
5212 int set_extent_buffer_dirty(struct extent_buffer
*eb
)
5215 unsigned long num_pages
;
5218 check_buffer_tree_ref(eb
);
5220 was_dirty
= test_and_set_bit(EXTENT_BUFFER_DIRTY
, &eb
->bflags
);
5222 num_pages
= num_extent_pages(eb
->start
, eb
->len
);
5223 WARN_ON(atomic_read(&eb
->refs
) == 0);
5224 WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF
, &eb
->bflags
));
5226 for (i
= 0; i
< num_pages
; i
++)
5227 set_page_dirty(eb
->pages
[i
]);
5231 void clear_extent_buffer_uptodate(struct extent_buffer
*eb
)
5235 unsigned long num_pages
;
5237 clear_bit(EXTENT_BUFFER_UPTODATE
, &eb
->bflags
);
5238 num_pages
= num_extent_pages(eb
->start
, eb
->len
);
5239 for (i
= 0; i
< num_pages
; i
++) {
5240 page
= eb
->pages
[i
];
5242 ClearPageUptodate(page
);
5246 void set_extent_buffer_uptodate(struct extent_buffer
*eb
)
5250 unsigned long num_pages
;
5252 set_bit(EXTENT_BUFFER_UPTODATE
, &eb
->bflags
);
5253 num_pages
= num_extent_pages(eb
->start
, eb
->len
);
5254 for (i
= 0; i
< num_pages
; i
++) {
5255 page
= eb
->pages
[i
];
5256 SetPageUptodate(page
);
5260 int extent_buffer_uptodate(struct extent_buffer
*eb
)
5262 return test_bit(EXTENT_BUFFER_UPTODATE
, &eb
->bflags
);
5265 int read_extent_buffer_pages(struct extent_io_tree
*tree
,
5266 struct extent_buffer
*eb
, int wait
,
5267 get_extent_t
*get_extent
, int mirror_num
)
5273 int locked_pages
= 0;
5274 int all_uptodate
= 1;
5275 unsigned long num_pages
;
5276 unsigned long num_reads
= 0;
5277 struct bio
*bio
= NULL
;
5278 unsigned long bio_flags
= 0;
5280 if (test_bit(EXTENT_BUFFER_UPTODATE
, &eb
->bflags
))
5283 num_pages
= num_extent_pages(eb
->start
, eb
->len
);
5284 for (i
= 0; i
< num_pages
; i
++) {
5285 page
= eb
->pages
[i
];
5286 if (wait
== WAIT_NONE
) {
5287 if (!trylock_page(page
))
5295 * We need to firstly lock all pages to make sure that
5296 * the uptodate bit of our pages won't be affected by
5297 * clear_extent_buffer_uptodate().
5299 for (i
= 0; i
< num_pages
; i
++) {
5300 page
= eb
->pages
[i
];
5301 if (!PageUptodate(page
)) {
5308 set_bit(EXTENT_BUFFER_UPTODATE
, &eb
->bflags
);
5312 clear_bit(EXTENT_BUFFER_READ_ERR
, &eb
->bflags
);
5313 eb
->read_mirror
= 0;
5314 atomic_set(&eb
->io_pages
, num_reads
);
5315 for (i
= 0; i
< num_pages
; i
++) {
5316 page
= eb
->pages
[i
];
5318 if (!PageUptodate(page
)) {
5320 atomic_dec(&eb
->io_pages
);
5325 ClearPageError(page
);
5326 err
= __extent_read_full_page(tree
, page
,
5328 mirror_num
, &bio_flags
,
5333 * We use &bio in above __extent_read_full_page,
5334 * so we ensure that if it returns error, the
5335 * current page fails to add itself to bio and
5336 * it's been unlocked.
5338 * We must dec io_pages by ourselves.
5340 atomic_dec(&eb
->io_pages
);
5348 err
= submit_one_bio(bio
, mirror_num
, bio_flags
);
5353 if (ret
|| wait
!= WAIT_COMPLETE
)
5356 for (i
= 0; i
< num_pages
; i
++) {
5357 page
= eb
->pages
[i
];
5358 wait_on_page_locked(page
);
5359 if (!PageUptodate(page
))
5366 while (locked_pages
> 0) {
5368 page
= eb
->pages
[locked_pages
];
5374 void read_extent_buffer(const struct extent_buffer
*eb
, void *dstv
,
5375 unsigned long start
, unsigned long len
)
5381 char *dst
= (char *)dstv
;
5382 size_t start_offset
= eb
->start
& ((u64
)PAGE_SIZE
- 1);
5383 unsigned long i
= (start_offset
+ start
) >> PAGE_SHIFT
;
5385 if (start
+ len
> eb
->len
) {
5386 WARN(1, KERN_ERR
"btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
5387 eb
->start
, eb
->len
, start
, len
);
5388 memset(dst
, 0, len
);
5392 offset
= (start_offset
+ start
) & (PAGE_SIZE
- 1);
5395 page
= eb
->pages
[i
];
5397 cur
= min(len
, (PAGE_SIZE
- offset
));
5398 kaddr
= page_address(page
);
5399 memcpy(dst
, kaddr
+ offset
, cur
);
5408 int read_extent_buffer_to_user(const struct extent_buffer
*eb
,
5410 unsigned long start
, unsigned long len
)
5416 char __user
*dst
= (char __user
*)dstv
;
5417 size_t start_offset
= eb
->start
& ((u64
)PAGE_SIZE
- 1);
5418 unsigned long i
= (start_offset
+ start
) >> PAGE_SHIFT
;
5421 WARN_ON(start
> eb
->len
);
5422 WARN_ON(start
+ len
> eb
->start
+ eb
->len
);
5424 offset
= (start_offset
+ start
) & (PAGE_SIZE
- 1);
5427 page
= eb
->pages
[i
];
5429 cur
= min(len
, (PAGE_SIZE
- offset
));
5430 kaddr
= page_address(page
);
5431 if (copy_to_user(dst
, kaddr
+ offset
, cur
)) {
5446 * return 0 if the item is found within a page.
5447 * return 1 if the item spans two pages.
5448 * return -EINVAL otherwise.
5450 int map_private_extent_buffer(const struct extent_buffer
*eb
,
5451 unsigned long start
, unsigned long min_len
,
5452 char **map
, unsigned long *map_start
,
5453 unsigned long *map_len
)
5455 size_t offset
= start
& (PAGE_SIZE
- 1);
5458 size_t start_offset
= eb
->start
& ((u64
)PAGE_SIZE
- 1);
5459 unsigned long i
= (start_offset
+ start
) >> PAGE_SHIFT
;
5460 unsigned long end_i
= (start_offset
+ start
+ min_len
- 1) >>
5463 if (start
+ min_len
> eb
->len
) {
5464 WARN(1, KERN_ERR
"btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
5465 eb
->start
, eb
->len
, start
, min_len
);
5473 offset
= start_offset
;
5477 *map_start
= ((u64
)i
<< PAGE_SHIFT
) - start_offset
;
5481 kaddr
= page_address(p
);
5482 *map
= kaddr
+ offset
;
5483 *map_len
= PAGE_SIZE
- offset
;
5487 int memcmp_extent_buffer(const struct extent_buffer
*eb
, const void *ptrv
,
5488 unsigned long start
, unsigned long len
)
5494 char *ptr
= (char *)ptrv
;
5495 size_t start_offset
= eb
->start
& ((u64
)PAGE_SIZE
- 1);
5496 unsigned long i
= (start_offset
+ start
) >> PAGE_SHIFT
;
5499 WARN_ON(start
> eb
->len
);
5500 WARN_ON(start
+ len
> eb
->start
+ eb
->len
);
5502 offset
= (start_offset
+ start
) & (PAGE_SIZE
- 1);
5505 page
= eb
->pages
[i
];
5507 cur
= min(len
, (PAGE_SIZE
- offset
));
5509 kaddr
= page_address(page
);
5510 ret
= memcmp(ptr
, kaddr
+ offset
, cur
);
5522 void write_extent_buffer_chunk_tree_uuid(struct extent_buffer
*eb
,
5527 WARN_ON(!PageUptodate(eb
->pages
[0]));
5528 kaddr
= page_address(eb
->pages
[0]);
5529 memcpy(kaddr
+ offsetof(struct btrfs_header
, chunk_tree_uuid
), srcv
,
5533 void write_extent_buffer_fsid(struct extent_buffer
*eb
, const void *srcv
)
5537 WARN_ON(!PageUptodate(eb
->pages
[0]));
5538 kaddr
= page_address(eb
->pages
[0]);
5539 memcpy(kaddr
+ offsetof(struct btrfs_header
, fsid
), srcv
,
5543 void write_extent_buffer(struct extent_buffer
*eb
, const void *srcv
,
5544 unsigned long start
, unsigned long len
)
5550 char *src
= (char *)srcv
;
5551 size_t start_offset
= eb
->start
& ((u64
)PAGE_SIZE
- 1);
5552 unsigned long i
= (start_offset
+ start
) >> PAGE_SHIFT
;
5554 WARN_ON(start
> eb
->len
);
5555 WARN_ON(start
+ len
> eb
->start
+ eb
->len
);
5557 offset
= (start_offset
+ start
) & (PAGE_SIZE
- 1);
5560 page
= eb
->pages
[i
];
5561 WARN_ON(!PageUptodate(page
));
5563 cur
= min(len
, PAGE_SIZE
- offset
);
5564 kaddr
= page_address(page
);
5565 memcpy(kaddr
+ offset
, src
, cur
);
5574 void memzero_extent_buffer(struct extent_buffer
*eb
, unsigned long start
,
5581 size_t start_offset
= eb
->start
& ((u64
)PAGE_SIZE
- 1);
5582 unsigned long i
= (start_offset
+ start
) >> PAGE_SHIFT
;
5584 WARN_ON(start
> eb
->len
);
5585 WARN_ON(start
+ len
> eb
->start
+ eb
->len
);
5587 offset
= (start_offset
+ start
) & (PAGE_SIZE
- 1);
5590 page
= eb
->pages
[i
];
5591 WARN_ON(!PageUptodate(page
));
5593 cur
= min(len
, PAGE_SIZE
- offset
);
5594 kaddr
= page_address(page
);
5595 memset(kaddr
+ offset
, 0, cur
);
5603 void copy_extent_buffer_full(struct extent_buffer
*dst
,
5604 struct extent_buffer
*src
)
5609 ASSERT(dst
->len
== src
->len
);
5611 num_pages
= num_extent_pages(dst
->start
, dst
->len
);
5612 for (i
= 0; i
< num_pages
; i
++)
5613 copy_page(page_address(dst
->pages
[i
]),
5614 page_address(src
->pages
[i
]));
5617 void copy_extent_buffer(struct extent_buffer
*dst
, struct extent_buffer
*src
,
5618 unsigned long dst_offset
, unsigned long src_offset
,
5621 u64 dst_len
= dst
->len
;
5626 size_t start_offset
= dst
->start
& ((u64
)PAGE_SIZE
- 1);
5627 unsigned long i
= (start_offset
+ dst_offset
) >> PAGE_SHIFT
;
5629 WARN_ON(src
->len
!= dst_len
);
5631 offset
= (start_offset
+ dst_offset
) &
5635 page
= dst
->pages
[i
];
5636 WARN_ON(!PageUptodate(page
));
5638 cur
= min(len
, (unsigned long)(PAGE_SIZE
- offset
));
5640 kaddr
= page_address(page
);
5641 read_extent_buffer(src
, kaddr
+ offset
, src_offset
, cur
);
5650 void le_bitmap_set(u8
*map
, unsigned int start
, int len
)
5652 u8
*p
= map
+ BIT_BYTE(start
);
5653 const unsigned int size
= start
+ len
;
5654 int bits_to_set
= BITS_PER_BYTE
- (start
% BITS_PER_BYTE
);
5655 u8 mask_to_set
= BITMAP_FIRST_BYTE_MASK(start
);
5657 while (len
- bits_to_set
>= 0) {
5660 bits_to_set
= BITS_PER_BYTE
;
5665 mask_to_set
&= BITMAP_LAST_BYTE_MASK(size
);
5670 void le_bitmap_clear(u8
*map
, unsigned int start
, int len
)
5672 u8
*p
= map
+ BIT_BYTE(start
);
5673 const unsigned int size
= start
+ len
;
5674 int bits_to_clear
= BITS_PER_BYTE
- (start
% BITS_PER_BYTE
);
5675 u8 mask_to_clear
= BITMAP_FIRST_BYTE_MASK(start
);
5677 while (len
- bits_to_clear
>= 0) {
5678 *p
&= ~mask_to_clear
;
5679 len
-= bits_to_clear
;
5680 bits_to_clear
= BITS_PER_BYTE
;
5685 mask_to_clear
&= BITMAP_LAST_BYTE_MASK(size
);
5686 *p
&= ~mask_to_clear
;
5691 * eb_bitmap_offset() - calculate the page and offset of the byte containing the
5693 * @eb: the extent buffer
5694 * @start: offset of the bitmap item in the extent buffer
5696 * @page_index: return index of the page in the extent buffer that contains the
5698 * @page_offset: return offset into the page given by page_index
5700 * This helper hides the ugliness of finding the byte in an extent buffer which
5701 * contains a given bit.
5703 static inline void eb_bitmap_offset(struct extent_buffer
*eb
,
5704 unsigned long start
, unsigned long nr
,
5705 unsigned long *page_index
,
5706 size_t *page_offset
)
5708 size_t start_offset
= eb
->start
& ((u64
)PAGE_SIZE
- 1);
5709 size_t byte_offset
= BIT_BYTE(nr
);
5713 * The byte we want is the offset of the extent buffer + the offset of
5714 * the bitmap item in the extent buffer + the offset of the byte in the
5717 offset
= start_offset
+ start
+ byte_offset
;
5719 *page_index
= offset
>> PAGE_SHIFT
;
5720 *page_offset
= offset
& (PAGE_SIZE
- 1);
5724 * extent_buffer_test_bit - determine whether a bit in a bitmap item is set
5725 * @eb: the extent buffer
5726 * @start: offset of the bitmap item in the extent buffer
5727 * @nr: bit number to test
5729 int extent_buffer_test_bit(struct extent_buffer
*eb
, unsigned long start
,
5737 eb_bitmap_offset(eb
, start
, nr
, &i
, &offset
);
5738 page
= eb
->pages
[i
];
5739 WARN_ON(!PageUptodate(page
));
5740 kaddr
= page_address(page
);
5741 return 1U & (kaddr
[offset
] >> (nr
& (BITS_PER_BYTE
- 1)));
5745 * extent_buffer_bitmap_set - set an area of a bitmap
5746 * @eb: the extent buffer
5747 * @start: offset of the bitmap item in the extent buffer
5748 * @pos: bit number of the first bit
5749 * @len: number of bits to set
5751 void extent_buffer_bitmap_set(struct extent_buffer
*eb
, unsigned long start
,
5752 unsigned long pos
, unsigned long len
)
5758 const unsigned int size
= pos
+ len
;
5759 int bits_to_set
= BITS_PER_BYTE
- (pos
% BITS_PER_BYTE
);
5760 u8 mask_to_set
= BITMAP_FIRST_BYTE_MASK(pos
);
5762 eb_bitmap_offset(eb
, start
, pos
, &i
, &offset
);
5763 page
= eb
->pages
[i
];
5764 WARN_ON(!PageUptodate(page
));
5765 kaddr
= page_address(page
);
5767 while (len
>= bits_to_set
) {
5768 kaddr
[offset
] |= mask_to_set
;
5770 bits_to_set
= BITS_PER_BYTE
;
5772 if (++offset
>= PAGE_SIZE
&& len
> 0) {
5774 page
= eb
->pages
[++i
];
5775 WARN_ON(!PageUptodate(page
));
5776 kaddr
= page_address(page
);
5780 mask_to_set
&= BITMAP_LAST_BYTE_MASK(size
);
5781 kaddr
[offset
] |= mask_to_set
;
5787 * extent_buffer_bitmap_clear - clear an area of a bitmap
5788 * @eb: the extent buffer
5789 * @start: offset of the bitmap item in the extent buffer
5790 * @pos: bit number of the first bit
5791 * @len: number of bits to clear
5793 void extent_buffer_bitmap_clear(struct extent_buffer
*eb
, unsigned long start
,
5794 unsigned long pos
, unsigned long len
)
5800 const unsigned int size
= pos
+ len
;
5801 int bits_to_clear
= BITS_PER_BYTE
- (pos
% BITS_PER_BYTE
);
5802 u8 mask_to_clear
= BITMAP_FIRST_BYTE_MASK(pos
);
5804 eb_bitmap_offset(eb
, start
, pos
, &i
, &offset
);
5805 page
= eb
->pages
[i
];
5806 WARN_ON(!PageUptodate(page
));
5807 kaddr
= page_address(page
);
5809 while (len
>= bits_to_clear
) {
5810 kaddr
[offset
] &= ~mask_to_clear
;
5811 len
-= bits_to_clear
;
5812 bits_to_clear
= BITS_PER_BYTE
;
5814 if (++offset
>= PAGE_SIZE
&& len
> 0) {
5816 page
= eb
->pages
[++i
];
5817 WARN_ON(!PageUptodate(page
));
5818 kaddr
= page_address(page
);
5822 mask_to_clear
&= BITMAP_LAST_BYTE_MASK(size
);
5823 kaddr
[offset
] &= ~mask_to_clear
;
5827 static inline bool areas_overlap(unsigned long src
, unsigned long dst
, unsigned long len
)
5829 unsigned long distance
= (src
> dst
) ? src
- dst
: dst
- src
;
5830 return distance
< len
;
5833 static void copy_pages(struct page
*dst_page
, struct page
*src_page
,
5834 unsigned long dst_off
, unsigned long src_off
,
5837 char *dst_kaddr
= page_address(dst_page
);
5839 int must_memmove
= 0;
5841 if (dst_page
!= src_page
) {
5842 src_kaddr
= page_address(src_page
);
5844 src_kaddr
= dst_kaddr
;
5845 if (areas_overlap(src_off
, dst_off
, len
))
5850 memmove(dst_kaddr
+ dst_off
, src_kaddr
+ src_off
, len
);
5852 memcpy(dst_kaddr
+ dst_off
, src_kaddr
+ src_off
, len
);
5855 void memcpy_extent_buffer(struct extent_buffer
*dst
, unsigned long dst_offset
,
5856 unsigned long src_offset
, unsigned long len
)
5858 struct btrfs_fs_info
*fs_info
= dst
->fs_info
;
5860 size_t dst_off_in_page
;
5861 size_t src_off_in_page
;
5862 size_t start_offset
= dst
->start
& ((u64
)PAGE_SIZE
- 1);
5863 unsigned long dst_i
;
5864 unsigned long src_i
;
5866 if (src_offset
+ len
> dst
->len
) {
5868 "memmove bogus src_offset %lu move len %lu dst len %lu",
5869 src_offset
, len
, dst
->len
);
5872 if (dst_offset
+ len
> dst
->len
) {
5874 "memmove bogus dst_offset %lu move len %lu dst len %lu",
5875 dst_offset
, len
, dst
->len
);
5880 dst_off_in_page
= (start_offset
+ dst_offset
) &
5882 src_off_in_page
= (start_offset
+ src_offset
) &
5885 dst_i
= (start_offset
+ dst_offset
) >> PAGE_SHIFT
;
5886 src_i
= (start_offset
+ src_offset
) >> PAGE_SHIFT
;
5888 cur
= min(len
, (unsigned long)(PAGE_SIZE
-
5890 cur
= min_t(unsigned long, cur
,
5891 (unsigned long)(PAGE_SIZE
- dst_off_in_page
));
5893 copy_pages(dst
->pages
[dst_i
], dst
->pages
[src_i
],
5894 dst_off_in_page
, src_off_in_page
, cur
);
5902 void memmove_extent_buffer(struct extent_buffer
*dst
, unsigned long dst_offset
,
5903 unsigned long src_offset
, unsigned long len
)
5905 struct btrfs_fs_info
*fs_info
= dst
->fs_info
;
5907 size_t dst_off_in_page
;
5908 size_t src_off_in_page
;
5909 unsigned long dst_end
= dst_offset
+ len
- 1;
5910 unsigned long src_end
= src_offset
+ len
- 1;
5911 size_t start_offset
= dst
->start
& ((u64
)PAGE_SIZE
- 1);
5912 unsigned long dst_i
;
5913 unsigned long src_i
;
5915 if (src_offset
+ len
> dst
->len
) {
5917 "memmove bogus src_offset %lu move len %lu len %lu",
5918 src_offset
, len
, dst
->len
);
5921 if (dst_offset
+ len
> dst
->len
) {
5923 "memmove bogus dst_offset %lu move len %lu len %lu",
5924 dst_offset
, len
, dst
->len
);
5927 if (dst_offset
< src_offset
) {
5928 memcpy_extent_buffer(dst
, dst_offset
, src_offset
, len
);
5932 dst_i
= (start_offset
+ dst_end
) >> PAGE_SHIFT
;
5933 src_i
= (start_offset
+ src_end
) >> PAGE_SHIFT
;
5935 dst_off_in_page
= (start_offset
+ dst_end
) &
5937 src_off_in_page
= (start_offset
+ src_end
) &
5940 cur
= min_t(unsigned long, len
, src_off_in_page
+ 1);
5941 cur
= min(cur
, dst_off_in_page
+ 1);
5942 copy_pages(dst
->pages
[dst_i
], dst
->pages
[src_i
],
5943 dst_off_in_page
- cur
+ 1,
5944 src_off_in_page
- cur
+ 1, cur
);
5952 int try_release_extent_buffer(struct page
*page
)
5954 struct extent_buffer
*eb
;
5957 * We need to make sure nobody is attaching this page to an eb right
5960 spin_lock(&page
->mapping
->private_lock
);
5961 if (!PagePrivate(page
)) {
5962 spin_unlock(&page
->mapping
->private_lock
);
5966 eb
= (struct extent_buffer
*)page
->private;
5970 * This is a little awful but should be ok, we need to make sure that
5971 * the eb doesn't disappear out from under us while we're looking at
5974 spin_lock(&eb
->refs_lock
);
5975 if (atomic_read(&eb
->refs
) != 1 || extent_buffer_under_io(eb
)) {
5976 spin_unlock(&eb
->refs_lock
);
5977 spin_unlock(&page
->mapping
->private_lock
);
5980 spin_unlock(&page
->mapping
->private_lock
);
5983 * If tree ref isn't set then we know the ref on this eb is a real ref,
5984 * so just return, this page will likely be freed soon anyway.
5986 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF
, &eb
->bflags
)) {
5987 spin_unlock(&eb
->refs_lock
);
5991 return release_extent_buffer(eb
);