1 #include <linux/bitops.h>
2 #include <linux/slab.h>
6 #include <linux/pagemap.h>
7 #include <linux/page-flags.h>
8 #include <linux/module.h>
9 #include <linux/spinlock.h>
10 #include <linux/blkdev.h>
11 #include "extent_map.h"
13 /* temporary define until extent_map moves out of btrfs */
14 struct kmem_cache
*btrfs_cache_create(const char *name
, size_t size
,
15 unsigned long extra_flags
,
16 void (*ctor
)(void *, struct kmem_cache
*,
19 static struct kmem_cache
*extent_map_cache
;
20 static struct kmem_cache
*extent_state_cache
;
26 struct rb_node rb_node
;
29 /* bits for the extent state */
30 #define EXTENT_DIRTY 1
31 #define EXTENT_WRITEBACK (1 << 1)
32 #define EXTENT_UPTODATE (1 << 2)
33 #define EXTENT_LOCKED (1 << 3)
34 #define EXTENT_NEW (1 << 4)
35 #define EXTENT_DELALLOC (1 << 5)
37 #define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
39 void __init
extent_map_init(void)
41 extent_map_cache
= btrfs_cache_create("extent_map",
42 sizeof(struct extent_map
),
45 extent_state_cache
= btrfs_cache_create("extent_state",
46 sizeof(struct extent_state
),
51 void __exit
extent_map_exit(void)
54 kmem_cache_destroy(extent_map_cache
);
55 if (extent_state_cache
)
56 kmem_cache_destroy(extent_state_cache
);
59 void extent_map_tree_init(struct extent_map_tree
*tree
,
60 struct address_space
*mapping
, gfp_t mask
)
62 tree
->map
.rb_node
= NULL
;
63 tree
->state
.rb_node
= NULL
;
65 rwlock_init(&tree
->lock
);
66 tree
->mapping
= mapping
;
68 EXPORT_SYMBOL(extent_map_tree_init
);
70 struct extent_map
*alloc_extent_map(gfp_t mask
)
72 struct extent_map
*em
;
73 em
= kmem_cache_alloc(extent_map_cache
, mask
);
74 if (!em
|| IS_ERR(em
))
77 atomic_set(&em
->refs
, 1);
80 EXPORT_SYMBOL(alloc_extent_map
);
82 void free_extent_map(struct extent_map
*em
)
86 if (atomic_dec_and_test(&em
->refs
)) {
88 kmem_cache_free(extent_map_cache
, em
);
91 EXPORT_SYMBOL(free_extent_map
);
94 struct extent_state
*alloc_extent_state(gfp_t mask
)
96 struct extent_state
*state
;
97 state
= kmem_cache_alloc(extent_state_cache
, mask
);
98 if (!state
|| IS_ERR(state
))
103 atomic_set(&state
->refs
, 1);
104 init_waitqueue_head(&state
->wq
);
107 EXPORT_SYMBOL(alloc_extent_state
);
109 void free_extent_state(struct extent_state
*state
)
113 if (atomic_dec_and_test(&state
->refs
)) {
114 WARN_ON(state
->in_tree
);
115 kmem_cache_free(extent_state_cache
, state
);
118 EXPORT_SYMBOL(free_extent_state
);
120 static struct rb_node
*tree_insert(struct rb_root
*root
, u64 offset
,
121 struct rb_node
*node
)
123 struct rb_node
** p
= &root
->rb_node
;
124 struct rb_node
* parent
= NULL
;
125 struct tree_entry
*entry
;
129 entry
= rb_entry(parent
, struct tree_entry
, rb_node
);
131 if (offset
< entry
->start
)
133 else if (offset
> entry
->end
)
139 entry
= rb_entry(node
, struct tree_entry
, rb_node
);
141 rb_link_node(node
, parent
, p
);
142 rb_insert_color(node
, root
);
146 static struct rb_node
*__tree_search(struct rb_root
*root
, u64 offset
,
147 struct rb_node
**prev_ret
)
149 struct rb_node
* n
= root
->rb_node
;
150 struct rb_node
*prev
= NULL
;
151 struct tree_entry
*entry
;
152 struct tree_entry
*prev_entry
= NULL
;
155 entry
= rb_entry(n
, struct tree_entry
, rb_node
);
159 if (offset
< entry
->start
)
161 else if (offset
> entry
->end
)
168 while(prev
&& offset
> prev_entry
->end
) {
169 prev
= rb_next(prev
);
170 prev_entry
= rb_entry(prev
, struct tree_entry
, rb_node
);
176 static inline struct rb_node
*tree_search(struct rb_root
*root
, u64 offset
)
178 struct rb_node
*prev
;
180 ret
= __tree_search(root
, offset
, &prev
);
186 static int tree_delete(struct rb_root
*root
, u64 offset
)
188 struct rb_node
*node
;
189 struct tree_entry
*entry
;
191 node
= __tree_search(root
, offset
, NULL
);
194 entry
= rb_entry(node
, struct tree_entry
, rb_node
);
196 rb_erase(node
, root
);
201 * add_extent_mapping tries a simple backward merge with existing
202 * mappings. The extent_map struct passed in will be inserted into
203 * the tree directly (no copies made, just a reference taken).
205 int add_extent_mapping(struct extent_map_tree
*tree
,
206 struct extent_map
*em
)
209 struct extent_map
*prev
= NULL
;
212 write_lock_irq(&tree
->lock
);
213 rb
= tree_insert(&tree
->map
, em
->end
, &em
->rb_node
);
215 prev
= rb_entry(rb
, struct extent_map
, rb_node
);
216 printk("found extent map %Lu %Lu on insert of %Lu %Lu\n", prev
->start
, prev
->end
, em
->start
, em
->end
);
220 atomic_inc(&em
->refs
);
221 if (em
->start
!= 0) {
222 rb
= rb_prev(&em
->rb_node
);
224 prev
= rb_entry(rb
, struct extent_map
, rb_node
);
225 if (prev
&& prev
->end
+ 1 == em
->start
&&
226 ((em
->block_start
== 0 && prev
->block_start
== 0) ||
227 (em
->block_start
== prev
->block_end
+ 1))) {
228 em
->start
= prev
->start
;
229 em
->block_start
= prev
->block_start
;
230 rb_erase(&prev
->rb_node
, &tree
->map
);
232 free_extent_map(prev
);
236 write_unlock_irq(&tree
->lock
);
239 EXPORT_SYMBOL(add_extent_mapping
);
242 * lookup_extent_mapping returns the first extent_map struct in the
243 * tree that intersects the [start, end] (inclusive) range. There may
244 * be additional objects in the tree that intersect, so check the object
245 * returned carefully to make sure you don't need additional lookups.
247 struct extent_map
*lookup_extent_mapping(struct extent_map_tree
*tree
,
250 struct extent_map
*em
;
251 struct rb_node
*rb_node
;
253 read_lock_irq(&tree
->lock
);
254 rb_node
= tree_search(&tree
->map
, start
);
259 if (IS_ERR(rb_node
)) {
260 em
= ERR_PTR(PTR_ERR(rb_node
));
263 em
= rb_entry(rb_node
, struct extent_map
, rb_node
);
264 if (em
->end
< start
|| em
->start
> end
) {
268 atomic_inc(&em
->refs
);
270 read_unlock_irq(&tree
->lock
);
273 EXPORT_SYMBOL(lookup_extent_mapping
);
276 * removes an extent_map struct from the tree. No reference counts are
277 * dropped, and no checks are done to see if the range is in use
279 int remove_extent_mapping(struct extent_map_tree
*tree
, struct extent_map
*em
)
283 write_lock_irq(&tree
->lock
);
284 ret
= tree_delete(&tree
->map
, em
->end
);
285 write_unlock_irq(&tree
->lock
);
288 EXPORT_SYMBOL(remove_extent_mapping
);
291 * utility function to look for merge candidates inside a given range.
292 * Any extents with matching state are merged together into a single
293 * extent in the tree. Extents with EXTENT_IO in their state field
294 * are not merged because the end_io handlers need to be able to do
295 * operations on them without sleeping (or doing allocations/splits).
297 * This should be called with the tree lock held.
299 static int merge_state(struct extent_map_tree
*tree
,
300 struct extent_state
*state
)
302 struct extent_state
*other
;
303 struct rb_node
*other_node
;
305 if (state
->state
& EXTENT_IOBITS
)
308 other_node
= rb_prev(&state
->rb_node
);
310 other
= rb_entry(other_node
, struct extent_state
, rb_node
);
311 if (other
->end
== state
->start
- 1 &&
312 other
->state
== state
->state
) {
313 state
->start
= other
->start
;
315 rb_erase(&other
->rb_node
, &tree
->state
);
316 free_extent_state(other
);
319 other_node
= rb_next(&state
->rb_node
);
321 other
= rb_entry(other_node
, struct extent_state
, rb_node
);
322 if (other
->start
== state
->end
+ 1 &&
323 other
->state
== state
->state
) {
324 other
->start
= state
->start
;
326 rb_erase(&state
->rb_node
, &tree
->state
);
327 free_extent_state(state
);
334 * insert an extent_state struct into the tree. 'bits' are set on the
335 * struct before it is inserted.
337 * This may return -EEXIST if the extent is already there, in which case the
338 * state struct is freed.
340 * The tree lock is not taken internally. This is a utility function and
341 * probably isn't what you want to call (see set/clear_extent_bit).
343 static int insert_state(struct extent_map_tree
*tree
,
344 struct extent_state
*state
, u64 start
, u64 end
,
347 struct rb_node
*node
;
350 printk("end < start %Lu %Lu\n", end
, start
);
353 state
->state
|= bits
;
354 state
->start
= start
;
356 if ((end
& 4095) == 0) {
357 printk("insert state %Lu %Lu strange end\n", start
, end
);
360 node
= tree_insert(&tree
->state
, end
, &state
->rb_node
);
362 struct extent_state
*found
;
363 found
= rb_entry(node
, struct extent_state
, rb_node
);
364 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found
->start
, found
->end
, start
, end
);
365 free_extent_state(state
);
368 merge_state(tree
, state
);
373 * split a given extent state struct in two, inserting the preallocated
374 * struct 'prealloc' as the newly created second half. 'split' indicates an
375 * offset inside 'orig' where it should be split.
378 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
379 * are two extent state structs in the tree:
380 * prealloc: [orig->start, split - 1]
381 * orig: [ split, orig->end ]
383 * The tree locks are not taken by this function. They need to be held
386 static int split_state(struct extent_map_tree
*tree
, struct extent_state
*orig
,
387 struct extent_state
*prealloc
, u64 split
)
389 struct rb_node
*node
;
390 prealloc
->start
= orig
->start
;
391 prealloc
->end
= split
- 1;
392 prealloc
->state
= orig
->state
;
394 if ((prealloc
->end
& 4095) == 0) {
395 printk("insert state %Lu %Lu strange end\n", prealloc
->start
,
399 node
= tree_insert(&tree
->state
, prealloc
->end
, &prealloc
->rb_node
);
401 struct extent_state
*found
;
402 found
= rb_entry(node
, struct extent_state
, rb_node
);
403 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found
->start
, found
->end
, prealloc
->start
, prealloc
->end
);
404 free_extent_state(prealloc
);
411 * utility function to clear some bits in an extent state struct.
412 * it will optionally wake up any one waiting on this state (wake == 1), or
413 * forcibly remove the state from the tree (delete == 1).
415 * If no bits are set on the state struct after clearing things, the
416 * struct is freed and removed from the tree
418 static int clear_state_bit(struct extent_map_tree
*tree
,
419 struct extent_state
*state
, int bits
, int wake
,
422 int ret
= state
->state
& bits
;
423 state
->state
&= ~bits
;
426 if (delete || state
->state
== 0) {
427 if (state
->in_tree
) {
428 rb_erase(&state
->rb_node
, &tree
->state
);
430 free_extent_state(state
);
435 merge_state(tree
, state
);
441 * clear some bits on a range in the tree. This may require splitting
442 * or inserting elements in the tree, so the gfp mask is used to
443 * indicate which allocations or sleeping are allowed.
445 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
446 * the given range from the tree regardless of state (ie for truncate).
448 * the range [start, end] is inclusive.
450 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
451 * bits were already set, or zero if none of the bits were already set.
453 int clear_extent_bit(struct extent_map_tree
*tree
, u64 start
, u64 end
,
454 int bits
, int wake
, int delete, gfp_t mask
)
456 struct extent_state
*state
;
457 struct extent_state
*prealloc
= NULL
;
458 struct rb_node
*node
;
464 if (!prealloc
&& (mask
& __GFP_WAIT
)) {
465 prealloc
= alloc_extent_state(mask
);
470 write_lock_irqsave(&tree
->lock
, flags
);
472 * this search will find the extents that end after
475 node
= tree_search(&tree
->state
, start
);
478 state
= rb_entry(node
, struct extent_state
, rb_node
);
479 if (state
->start
> end
)
481 WARN_ON(state
->end
< start
);
484 * | ---- desired range ---- |
486 * | ------------- state -------------- |
488 * We need to split the extent we found, and may flip
489 * bits on second half.
491 * If the extent we found extends past our range, we
492 * just split and search again. It'll get split again
493 * the next time though.
495 * If the extent we found is inside our range, we clear
496 * the desired bit on it.
499 if (state
->start
< start
) {
500 err
= split_state(tree
, state
, prealloc
, start
);
501 BUG_ON(err
== -EEXIST
);
505 if (state
->end
<= end
) {
506 start
= state
->end
+ 1;
507 set
|= clear_state_bit(tree
, state
, bits
,
510 start
= state
->start
;
515 * | ---- desired range ---- |
517 * We need to split the extent, and clear the bit
520 if (state
->start
<= end
&& state
->end
> end
) {
521 err
= split_state(tree
, state
, prealloc
, end
+ 1);
522 BUG_ON(err
== -EEXIST
);
526 set
|= clear_state_bit(tree
, prealloc
, bits
,
532 start
= state
->end
+ 1;
533 set
|= clear_state_bit(tree
, state
, bits
, wake
, delete);
537 write_unlock_irqrestore(&tree
->lock
, flags
);
539 free_extent_state(prealloc
);
546 write_unlock_irqrestore(&tree
->lock
, flags
);
547 if (mask
& __GFP_WAIT
)
551 EXPORT_SYMBOL(clear_extent_bit
);
553 static int wait_on_state(struct extent_map_tree
*tree
,
554 struct extent_state
*state
)
557 prepare_to_wait(&state
->wq
, &wait
, TASK_UNINTERRUPTIBLE
);
558 read_unlock_irq(&tree
->lock
);
560 read_lock_irq(&tree
->lock
);
561 finish_wait(&state
->wq
, &wait
);
566 * waits for one or more bits to clear on a range in the state tree.
567 * The range [start, end] is inclusive.
568 * The tree lock is taken by this function
570 int wait_extent_bit(struct extent_map_tree
*tree
, u64 start
, u64 end
, int bits
)
572 struct extent_state
*state
;
573 struct rb_node
*node
;
575 read_lock_irq(&tree
->lock
);
579 * this search will find all the extents that end after
582 node
= tree_search(&tree
->state
, start
);
586 state
= rb_entry(node
, struct extent_state
, rb_node
);
588 if (state
->start
> end
)
591 if (state
->state
& bits
) {
592 start
= state
->start
;
593 atomic_inc(&state
->refs
);
594 wait_on_state(tree
, state
);
595 free_extent_state(state
);
598 start
= state
->end
+ 1;
603 if (need_resched()) {
604 read_unlock_irq(&tree
->lock
);
606 read_lock_irq(&tree
->lock
);
610 read_unlock_irq(&tree
->lock
);
613 EXPORT_SYMBOL(wait_extent_bit
);
616 * set some bits on a range in the tree. This may require allocations
617 * or sleeping, so the gfp mask is used to indicate what is allowed.
619 * If 'exclusive' == 1, this will fail with -EEXIST if some part of the
620 * range already has the desired bits set. The start of the existing
621 * range is returned in failed_start in this case.
623 * [start, end] is inclusive
624 * This takes the tree lock.
626 int set_extent_bit(struct extent_map_tree
*tree
, u64 start
, u64 end
, int bits
,
627 int exclusive
, u64
*failed_start
, gfp_t mask
)
629 struct extent_state
*state
;
630 struct extent_state
*prealloc
= NULL
;
631 struct rb_node
*node
;
638 if (!prealloc
&& (mask
& __GFP_WAIT
)) {
639 prealloc
= alloc_extent_state(mask
);
644 write_lock_irqsave(&tree
->lock
, flags
);
646 * this search will find all the extents that end after
649 node
= tree_search(&tree
->state
, start
);
651 err
= insert_state(tree
, prealloc
, start
, end
, bits
);
653 BUG_ON(err
== -EEXIST
);
657 state
= rb_entry(node
, struct extent_state
, rb_node
);
658 last_start
= state
->start
;
659 last_end
= state
->end
;
662 * | ---- desired range ---- |
665 * Just lock what we found and keep going
667 if (state
->start
== start
&& state
->end
<= end
) {
668 set
= state
->state
& bits
;
669 if (set
&& exclusive
) {
670 *failed_start
= state
->start
;
674 state
->state
|= bits
;
675 start
= state
->end
+ 1;
676 merge_state(tree
, state
);
681 * | ---- desired range ---- |
684 * | ------------- state -------------- |
686 * We need to split the extent we found, and may flip bits on
689 * If the extent we found extends past our
690 * range, we just split and search again. It'll get split
691 * again the next time though.
693 * If the extent we found is inside our range, we set the
696 if (state
->start
< start
) {
697 set
= state
->state
& bits
;
698 if (exclusive
&& set
) {
699 *failed_start
= start
;
703 err
= split_state(tree
, state
, prealloc
, start
);
704 BUG_ON(err
== -EEXIST
);
708 if (state
->end
<= end
) {
709 state
->state
|= bits
;
710 start
= state
->end
+ 1;
711 merge_state(tree
, state
);
713 start
= state
->start
;
718 * | ---- desired range ---- |
719 * | state | or | state |
721 * There's a hole, we need to insert something in it and
722 * ignore the extent we found.
724 if (state
->start
> start
) {
726 if (end
< last_start
)
729 this_end
= last_start
-1;
730 err
= insert_state(tree
, prealloc
, start
, this_end
,
733 BUG_ON(err
== -EEXIST
);
736 start
= this_end
+ 1;
740 * | ---- desired range ---- |
742 * We need to split the extent, and set the bit
745 if (state
->start
<= end
&& state
->end
> end
) {
746 set
= state
->state
& bits
;
747 if (exclusive
&& set
) {
748 *failed_start
= start
;
752 err
= split_state(tree
, state
, prealloc
, end
+ 1);
753 BUG_ON(err
== -EEXIST
);
755 prealloc
->state
|= bits
;
756 merge_state(tree
, prealloc
);
764 write_unlock_irqrestore(&tree
->lock
, flags
);
766 free_extent_state(prealloc
);
773 write_unlock_irqrestore(&tree
->lock
, flags
);
774 if (mask
& __GFP_WAIT
)
778 EXPORT_SYMBOL(set_extent_bit
);
780 /* wrappers around set/clear extent bit */
781 int set_extent_dirty(struct extent_map_tree
*tree
, u64 start
, u64 end
,
784 return set_extent_bit(tree
, start
, end
, EXTENT_DIRTY
, 0, NULL
,
787 EXPORT_SYMBOL(set_extent_dirty
);
789 int set_extent_delalloc(struct extent_map_tree
*tree
, u64 start
, u64 end
,
792 return set_extent_bit(tree
, start
, end
,
793 EXTENT_DELALLOC
| EXTENT_DIRTY
, 0, NULL
,
796 EXPORT_SYMBOL(set_extent_delalloc
);
798 int clear_extent_dirty(struct extent_map_tree
*tree
, u64 start
, u64 end
,
801 return clear_extent_bit(tree
, start
, end
,
802 EXTENT_DIRTY
| EXTENT_DELALLOC
, 0, 0, mask
);
804 EXPORT_SYMBOL(clear_extent_dirty
);
806 int set_extent_new(struct extent_map_tree
*tree
, u64 start
, u64 end
,
809 return set_extent_bit(tree
, start
, end
, EXTENT_NEW
, 0, NULL
,
812 EXPORT_SYMBOL(set_extent_new
);
814 int clear_extent_new(struct extent_map_tree
*tree
, u64 start
, u64 end
,
817 return clear_extent_bit(tree
, start
, end
, EXTENT_NEW
, 0, 0, mask
);
819 EXPORT_SYMBOL(clear_extent_new
);
821 int set_extent_uptodate(struct extent_map_tree
*tree
, u64 start
, u64 end
,
824 return set_extent_bit(tree
, start
, end
, EXTENT_UPTODATE
, 0, NULL
,
827 EXPORT_SYMBOL(set_extent_uptodate
);
829 int clear_extent_uptodate(struct extent_map_tree
*tree
, u64 start
, u64 end
,
832 return clear_extent_bit(tree
, start
, end
, EXTENT_UPTODATE
, 0, 0, mask
);
834 EXPORT_SYMBOL(clear_extent_uptodate
);
836 int set_extent_writeback(struct extent_map_tree
*tree
, u64 start
, u64 end
,
839 return set_extent_bit(tree
, start
, end
, EXTENT_WRITEBACK
,
842 EXPORT_SYMBOL(set_extent_writeback
);
844 int clear_extent_writeback(struct extent_map_tree
*tree
, u64 start
, u64 end
,
847 return clear_extent_bit(tree
, start
, end
, EXTENT_WRITEBACK
, 1, 0, mask
);
849 EXPORT_SYMBOL(clear_extent_writeback
);
851 int wait_on_extent_writeback(struct extent_map_tree
*tree
, u64 start
, u64 end
)
853 return wait_extent_bit(tree
, start
, end
, EXTENT_WRITEBACK
);
855 EXPORT_SYMBOL(wait_on_extent_writeback
);
858 * locks a range in ascending order, waiting for any locked regions
859 * it hits on the way. [start,end] are inclusive, and this will sleep.
861 int lock_extent(struct extent_map_tree
*tree
, u64 start
, u64 end
, gfp_t mask
)
866 err
= set_extent_bit(tree
, start
, end
, EXTENT_LOCKED
, 1,
867 &failed_start
, mask
);
868 if (err
== -EEXIST
&& (mask
& __GFP_WAIT
)) {
869 wait_extent_bit(tree
, failed_start
, end
, EXTENT_LOCKED
);
870 start
= failed_start
;
874 WARN_ON(start
> end
);
878 EXPORT_SYMBOL(lock_extent
);
880 int unlock_extent(struct extent_map_tree
*tree
, u64 start
, u64 end
,
883 return clear_extent_bit(tree
, start
, end
, EXTENT_LOCKED
, 1, 0, mask
);
885 EXPORT_SYMBOL(unlock_extent
);
888 * helper function to set pages and extents in the tree dirty
890 int set_range_dirty(struct extent_map_tree
*tree
, u64 start
, u64 end
)
892 unsigned long index
= start
>> PAGE_CACHE_SHIFT
;
893 unsigned long end_index
= end
>> PAGE_CACHE_SHIFT
;
896 while (index
<= end_index
) {
897 page
= find_get_page(tree
->mapping
, index
);
899 __set_page_dirty_nobuffers(page
);
900 page_cache_release(page
);
903 set_extent_dirty(tree
, start
, end
, GFP_NOFS
);
906 EXPORT_SYMBOL(set_range_dirty
);
909 * helper function to set both pages and extents in the tree writeback
911 int set_range_writeback(struct extent_map_tree
*tree
, u64 start
, u64 end
)
913 unsigned long index
= start
>> PAGE_CACHE_SHIFT
;
914 unsigned long end_index
= end
>> PAGE_CACHE_SHIFT
;
917 while (index
<= end_index
) {
918 page
= find_get_page(tree
->mapping
, index
);
920 set_page_writeback(page
);
921 page_cache_release(page
);
924 set_extent_writeback(tree
, start
, end
, GFP_NOFS
);
927 EXPORT_SYMBOL(set_range_writeback
);
929 u64
find_lock_delalloc_range(struct extent_map_tree
*tree
,
930 u64 start
, u64 lock_start
, u64
*end
, u64 max_bytes
)
932 struct rb_node
*node
;
933 struct extent_state
*state
;
934 u64 cur_start
= start
;
938 write_lock_irq(&tree
->lock
);
940 * this search will find all the extents that end after
944 node
= tree_search(&tree
->state
, cur_start
);
945 if (!node
|| IS_ERR(node
)) {
950 state
= rb_entry(node
, struct extent_state
, rb_node
);
951 if (state
->start
!= cur_start
) {
954 if (!(state
->state
& EXTENT_DELALLOC
)) {
957 if (state
->start
>= lock_start
) {
958 if (state
->state
& EXTENT_LOCKED
) {
960 atomic_inc(&state
->refs
);
961 write_unlock_irq(&tree
->lock
);
963 write_lock_irq(&tree
->lock
);
964 finish_wait(&state
->wq
, &wait
);
965 free_extent_state(state
);
968 state
->state
|= EXTENT_LOCKED
;
972 cur_start
= state
->end
+ 1;
973 node
= rb_next(node
);
976 total_bytes
= state
->end
- state
->start
+ 1;
977 if (total_bytes
>= max_bytes
)
981 write_unlock_irq(&tree
->lock
);
986 * helper function to lock both pages and extents in the tree.
987 * pages must be locked first.
989 int lock_range(struct extent_map_tree
*tree
, u64 start
, u64 end
)
991 unsigned long index
= start
>> PAGE_CACHE_SHIFT
;
992 unsigned long end_index
= end
>> PAGE_CACHE_SHIFT
;
996 while (index
<= end_index
) {
997 page
= grab_cache_page(tree
->mapping
, index
);
1003 err
= PTR_ERR(page
);
1008 lock_extent(tree
, start
, end
, GFP_NOFS
);
1013 * we failed above in getting the page at 'index', so we undo here
1014 * up to but not including the page at 'index'
1017 index
= start
>> PAGE_CACHE_SHIFT
;
1018 while (index
< end_index
) {
1019 page
= find_get_page(tree
->mapping
, index
);
1021 page_cache_release(page
);
1026 EXPORT_SYMBOL(lock_range
);
1029 * helper function to unlock both pages and extents in the tree.
1031 int unlock_range(struct extent_map_tree
*tree
, u64 start
, u64 end
)
1033 unsigned long index
= start
>> PAGE_CACHE_SHIFT
;
1034 unsigned long end_index
= end
>> PAGE_CACHE_SHIFT
;
1037 while (index
<= end_index
) {
1038 page
= find_get_page(tree
->mapping
, index
);
1040 page_cache_release(page
);
1043 unlock_extent(tree
, start
, end
, GFP_NOFS
);
1046 EXPORT_SYMBOL(unlock_range
);
1048 int set_state_private(struct extent_map_tree
*tree
, u64 start
, u64
private)
1050 struct rb_node
*node
;
1051 struct extent_state
*state
;
1054 write_lock_irq(&tree
->lock
);
1056 * this search will find all the extents that end after
1059 node
= tree_search(&tree
->state
, start
);
1060 if (!node
|| IS_ERR(node
)) {
1064 state
= rb_entry(node
, struct extent_state
, rb_node
);
1065 if (state
->start
!= start
) {
1069 state
->private = private;
1071 write_unlock_irq(&tree
->lock
);
1076 int get_state_private(struct extent_map_tree
*tree
, u64 start
, u64
*private)
1078 struct rb_node
*node
;
1079 struct extent_state
*state
;
1082 read_lock_irq(&tree
->lock
);
1084 * this search will find all the extents that end after
1087 node
= tree_search(&tree
->state
, start
);
1088 if (!node
|| IS_ERR(node
)) {
1092 state
= rb_entry(node
, struct extent_state
, rb_node
);
1093 if (state
->start
!= start
) {
1097 *private = state
->private;
1099 read_unlock_irq(&tree
->lock
);
1104 * searches a range in the state tree for a given mask.
1105 * If 'filled' == 1, this returns 1 only if ever extent in the tree
1106 * has the bits set. Otherwise, 1 is returned if any bit in the
1107 * range is found set.
1109 static int test_range_bit(struct extent_map_tree
*tree
, u64 start
, u64 end
,
1110 int bits
, int filled
)
1112 struct extent_state
*state
= NULL
;
1113 struct rb_node
*node
;
1116 read_lock_irq(&tree
->lock
);
1117 node
= tree_search(&tree
->state
, start
);
1118 while (node
&& start
<= end
) {
1119 state
= rb_entry(node
, struct extent_state
, rb_node
);
1120 if (state
->start
> end
)
1123 if (filled
&& state
->start
> start
) {
1127 if (state
->state
& bits
) {
1131 } else if (filled
) {
1135 start
= state
->end
+ 1;
1138 node
= rb_next(node
);
1140 read_unlock_irq(&tree
->lock
);
1145 * helper function to set a given page up to date if all the
1146 * extents in the tree for that page are up to date
1148 static int check_page_uptodate(struct extent_map_tree
*tree
,
1151 u64 start
= page
->index
<< PAGE_CACHE_SHIFT
;
1152 u64 end
= start
+ PAGE_CACHE_SIZE
- 1;
1153 if (test_range_bit(tree
, start
, end
, EXTENT_UPTODATE
, 1))
1154 SetPageUptodate(page
);
1159 * helper function to unlock a page if all the extents in the tree
1160 * for that page are unlocked
1162 static int check_page_locked(struct extent_map_tree
*tree
,
1165 u64 start
= page
->index
<< PAGE_CACHE_SHIFT
;
1166 u64 end
= start
+ PAGE_CACHE_SIZE
- 1;
1167 if (!test_range_bit(tree
, start
, end
, EXTENT_LOCKED
, 0))
1173 * helper function to end page writeback if all the extents
1174 * in the tree for that page are done with writeback
1176 static int check_page_writeback(struct extent_map_tree
*tree
,
1179 u64 start
= page
->index
<< PAGE_CACHE_SHIFT
;
1180 u64 end
= start
+ PAGE_CACHE_SIZE
- 1;
1181 if (!test_range_bit(tree
, start
, end
, EXTENT_WRITEBACK
, 0))
1182 end_page_writeback(page
);
1186 /* lots and lots of room for performance fixes in the end_bio funcs */
1189 * after a writepage IO is done, we need to:
1190 * clear the uptodate bits on error
1191 * clear the writeback bits in the extent tree for this IO
1192 * end_page_writeback if the page has no more pending IO
1194 * Scheduling is not allowed, so the extent state tree is expected
1195 * to have one and only one object corresponding to this IO.
1197 static int end_bio_extent_writepage(struct bio
*bio
,
1198 unsigned int bytes_done
, int err
)
1200 const int uptodate
= test_bit(BIO_UPTODATE
, &bio
->bi_flags
);
1201 struct bio_vec
*bvec
= bio
->bi_io_vec
+ bio
->bi_vcnt
- 1;
1202 struct extent_map_tree
*tree
= bio
->bi_private
;
1211 struct page
*page
= bvec
->bv_page
;
1212 start
= (page
->index
<< PAGE_CACHE_SHIFT
) + bvec
->bv_offset
;
1213 end
= start
+ bvec
->bv_len
- 1;
1215 if (bvec
->bv_offset
== 0 && bvec
->bv_len
== PAGE_CACHE_SIZE
)
1220 if (--bvec
>= bio
->bi_io_vec
)
1221 prefetchw(&bvec
->bv_page
->flags
);
1224 clear_extent_uptodate(tree
, start
, end
, GFP_ATOMIC
);
1225 ClearPageUptodate(page
);
1228 clear_extent_writeback(tree
, start
, end
, GFP_ATOMIC
);
1231 end_page_writeback(page
);
1233 check_page_writeback(tree
, page
);
1234 if (tree
->ops
&& tree
->ops
->writepage_end_io_hook
)
1235 tree
->ops
->writepage_end_io_hook(page
, start
, end
);
1236 } while (bvec
>= bio
->bi_io_vec
);
1243 * after a readpage IO is done, we need to:
1244 * clear the uptodate bits on error
1245 * set the uptodate bits if things worked
1246 * set the page up to date if all extents in the tree are uptodate
1247 * clear the lock bit in the extent tree
1248 * unlock the page if there are no other extents locked for it
1250 * Scheduling is not allowed, so the extent state tree is expected
1251 * to have one and only one object corresponding to this IO.
1253 static int end_bio_extent_readpage(struct bio
*bio
,
1254 unsigned int bytes_done
, int err
)
1256 int uptodate
= test_bit(BIO_UPTODATE
, &bio
->bi_flags
);
1257 struct bio_vec
*bvec
= bio
->bi_io_vec
+ bio
->bi_vcnt
- 1;
1258 struct extent_map_tree
*tree
= bio
->bi_private
;
1268 struct page
*page
= bvec
->bv_page
;
1269 start
= (page
->index
<< PAGE_CACHE_SHIFT
) + bvec
->bv_offset
;
1270 end
= start
+ bvec
->bv_len
- 1;
1272 if (bvec
->bv_offset
== 0 && bvec
->bv_len
== PAGE_CACHE_SIZE
)
1277 if (--bvec
>= bio
->bi_io_vec
)
1278 prefetchw(&bvec
->bv_page
->flags
);
1280 if (uptodate
&& tree
->ops
&& tree
->ops
->readpage_end_io_hook
) {
1281 ret
= tree
->ops
->readpage_end_io_hook(page
, start
, end
);
1286 set_extent_uptodate(tree
, start
, end
, GFP_ATOMIC
);
1288 SetPageUptodate(page
);
1290 check_page_uptodate(tree
, page
);
1292 ClearPageUptodate(page
);
1296 unlock_extent(tree
, start
, end
, GFP_ATOMIC
);
1301 check_page_locked(tree
, page
);
1302 } while (bvec
>= bio
->bi_io_vec
);
1309 * IO done from prepare_write is pretty simple, we just unlock
1310 * the structs in the extent tree when done, and set the uptodate bits
1313 static int end_bio_extent_preparewrite(struct bio
*bio
,
1314 unsigned int bytes_done
, int err
)
1316 const int uptodate
= test_bit(BIO_UPTODATE
, &bio
->bi_flags
);
1317 struct bio_vec
*bvec
= bio
->bi_io_vec
+ bio
->bi_vcnt
- 1;
1318 struct extent_map_tree
*tree
= bio
->bi_private
;
1326 struct page
*page
= bvec
->bv_page
;
1327 start
= (page
->index
<< PAGE_CACHE_SHIFT
) + bvec
->bv_offset
;
1328 end
= start
+ bvec
->bv_len
- 1;
1330 if (--bvec
>= bio
->bi_io_vec
)
1331 prefetchw(&bvec
->bv_page
->flags
);
1334 set_extent_uptodate(tree
, start
, end
, GFP_ATOMIC
);
1336 ClearPageUptodate(page
);
1340 unlock_extent(tree
, start
, end
, GFP_ATOMIC
);
1342 } while (bvec
>= bio
->bi_io_vec
);
1348 static int submit_extent_page(int rw
, struct extent_map_tree
*tree
,
1349 struct page
*page
, sector_t sector
,
1350 size_t size
, unsigned long offset
,
1351 struct block_device
*bdev
,
1352 bio_end_io_t end_io_func
)
1357 bio
= bio_alloc(GFP_NOIO
, 1);
1359 bio
->bi_sector
= sector
;
1360 bio
->bi_bdev
= bdev
;
1361 bio
->bi_io_vec
[0].bv_page
= page
;
1362 bio
->bi_io_vec
[0].bv_len
= size
;
1363 bio
->bi_io_vec
[0].bv_offset
= offset
;
1367 bio
->bi_size
= size
;
1369 bio
->bi_end_io
= end_io_func
;
1370 bio
->bi_private
= tree
;
1373 submit_bio(rw
, bio
);
1375 if (bio_flagged(bio
, BIO_EOPNOTSUPP
))
1382 void set_page_extent_mapped(struct page
*page
)
1384 if (!PagePrivate(page
)) {
1385 SetPagePrivate(page
);
1386 WARN_ON(!page
->mapping
->a_ops
->invalidatepage
);
1387 set_page_private(page
, 1);
1388 page_cache_get(page
);
1393 * basic readpage implementation. Locked extent state structs are inserted
1394 * into the tree that are removed when the IO is done (by the end_io
1397 int extent_read_full_page(struct extent_map_tree
*tree
, struct page
*page
,
1398 get_extent_t
*get_extent
)
1400 struct inode
*inode
= page
->mapping
->host
;
1401 u64 start
= page
->index
<< PAGE_CACHE_SHIFT
;
1402 u64 page_end
= start
+ PAGE_CACHE_SIZE
- 1;
1406 u64 last_byte
= i_size_read(inode
);
1410 struct extent_map
*em
;
1411 struct block_device
*bdev
;
1414 size_t page_offset
= 0;
1416 size_t blocksize
= inode
->i_sb
->s_blocksize
;
1418 set_page_extent_mapped(page
);
1421 lock_extent(tree
, start
, end
, GFP_NOFS
);
1423 while (cur
<= end
) {
1424 if (cur
>= last_byte
) {
1425 iosize
= PAGE_CACHE_SIZE
- page_offset
;
1426 zero_user_page(page
, page_offset
, iosize
, KM_USER0
);
1427 set_extent_uptodate(tree
, cur
, cur
+ iosize
- 1,
1429 unlock_extent(tree
, cur
, cur
+ iosize
- 1, GFP_NOFS
);
1432 em
= get_extent(inode
, page
, page_offset
, cur
, end
, 0);
1433 if (IS_ERR(em
) || !em
) {
1435 unlock_extent(tree
, cur
, end
, GFP_NOFS
);
1439 extent_offset
= cur
- em
->start
;
1440 BUG_ON(em
->end
< cur
);
1443 iosize
= min(em
->end
- cur
, end
- cur
) + 1;
1444 cur_end
= min(em
->end
, end
);
1445 iosize
= (iosize
+ blocksize
- 1) & ~((u64
)blocksize
- 1);
1446 sector
= (em
->block_start
+ extent_offset
) >> 9;
1448 block_start
= em
->block_start
;
1449 free_extent_map(em
);
1452 /* we've found a hole, just zero and go on */
1453 if (block_start
== 0) {
1454 zero_user_page(page
, page_offset
, iosize
, KM_USER0
);
1455 set_extent_uptodate(tree
, cur
, cur
+ iosize
- 1,
1457 unlock_extent(tree
, cur
, cur
+ iosize
- 1, GFP_NOFS
);
1459 page_offset
+= iosize
;
1462 /* the get_extent function already copied into the page */
1463 if (test_range_bit(tree
, cur
, cur_end
, EXTENT_UPTODATE
, 1)) {
1464 unlock_extent(tree
, cur
, cur
+ iosize
- 1, GFP_NOFS
);
1466 page_offset
+= iosize
;
1471 if (tree
->ops
&& tree
->ops
->readpage_io_hook
) {
1472 ret
= tree
->ops
->readpage_io_hook(page
, cur
,
1476 ret
= submit_extent_page(READ
, tree
, page
,
1477 sector
, iosize
, page_offset
,
1478 bdev
, end_bio_extent_readpage
);
1483 page_offset
+= iosize
;
1487 if (!PageError(page
))
1488 SetPageUptodate(page
);
1493 EXPORT_SYMBOL(extent_read_full_page
);
1496 * the writepage semantics are similar to regular writepage. extent
1497 * records are inserted to lock ranges in the tree, and as dirty areas
1498 * are found, they are marked writeback. Then the lock bits are removed
1499 * and the end_io handler clears the writeback ranges
1501 int extent_write_full_page(struct extent_map_tree
*tree
, struct page
*page
,
1502 get_extent_t
*get_extent
,
1503 struct writeback_control
*wbc
)
1505 struct inode
*inode
= page
->mapping
->host
;
1506 u64 start
= page
->index
<< PAGE_CACHE_SHIFT
;
1507 u64 page_end
= start
+ PAGE_CACHE_SIZE
- 1;
1511 u64 last_byte
= i_size_read(inode
);
1514 struct extent_map
*em
;
1515 struct block_device
*bdev
;
1518 size_t page_offset
= 0;
1521 loff_t i_size
= i_size_read(inode
);
1522 unsigned long end_index
= i_size
>> PAGE_CACHE_SHIFT
;
1526 WARN_ON(!PageLocked(page
));
1527 if (page
->index
> end_index
) {
1528 clear_extent_dirty(tree
, start
, page_end
, GFP_NOFS
);
1533 if (page
->index
== end_index
) {
1534 size_t offset
= i_size
& (PAGE_CACHE_SIZE
- 1);
1535 zero_user_page(page
, offset
,
1536 PAGE_CACHE_SIZE
- offset
, KM_USER0
);
1539 set_page_extent_mapped(page
);
1541 lock_extent(tree
, start
, page_end
, GFP_NOFS
);
1542 nr_delalloc
= find_lock_delalloc_range(tree
, start
, page_end
+ 1,
1546 tree
->ops
->fill_delalloc(inode
, start
, delalloc_end
);
1547 if (delalloc_end
>= page_end
+ 1) {
1548 clear_extent_bit(tree
, page_end
+ 1, delalloc_end
,
1549 EXTENT_LOCKED
| EXTENT_DELALLOC
,
1552 clear_extent_bit(tree
, start
, page_end
, EXTENT_DELALLOC
,
1554 if (test_range_bit(tree
, start
, page_end
, EXTENT_DELALLOC
, 0)) {
1555 printk("found delalloc bits after clear extent_bit\n");
1557 } else if (test_range_bit(tree
, start
, page_end
, EXTENT_DELALLOC
, 0)) {
1558 printk("found delalloc bits after find_delalloc_range returns 0\n");
1562 if (test_range_bit(tree
, start
, page_end
, EXTENT_DELALLOC
, 0)) {
1563 printk("found delalloc bits after lock_extent\n");
1566 if (last_byte
<= start
) {
1567 clear_extent_dirty(tree
, start
, page_end
, GFP_NOFS
);
1571 set_extent_uptodate(tree
, start
, page_end
, GFP_NOFS
);
1572 blocksize
= inode
->i_sb
->s_blocksize
;
1574 while (cur
<= end
) {
1575 if (cur
>= last_byte
) {
1576 clear_extent_dirty(tree
, cur
, page_end
, GFP_NOFS
);
1579 em
= get_extent(inode
, page
, page_offset
, cur
, end
, 0);
1580 if (IS_ERR(em
) || !em
) {
1585 extent_offset
= cur
- em
->start
;
1586 BUG_ON(em
->end
< cur
);
1588 iosize
= min(em
->end
- cur
, end
- cur
) + 1;
1589 iosize
= (iosize
+ blocksize
- 1) & ~((u64
)blocksize
- 1);
1590 sector
= (em
->block_start
+ extent_offset
) >> 9;
1592 block_start
= em
->block_start
;
1593 free_extent_map(em
);
1596 if (block_start
== 0 || block_start
== EXTENT_MAP_INLINE
) {
1597 clear_extent_dirty(tree
, cur
,
1598 cur
+ iosize
- 1, GFP_NOFS
);
1600 page_offset
+= iosize
;
1604 /* leave this out until we have a page_mkwrite call */
1605 if (0 && !test_range_bit(tree
, cur
, cur
+ iosize
- 1,
1608 page_offset
+= iosize
;
1611 clear_extent_dirty(tree
, cur
, cur
+ iosize
- 1, GFP_NOFS
);
1612 if (tree
->ops
&& tree
->ops
->writepage_io_hook
) {
1613 ret
= tree
->ops
->writepage_io_hook(page
, cur
,
1621 set_range_writeback(tree
, cur
, cur
+ iosize
- 1);
1622 ret
= submit_extent_page(WRITE
, tree
, page
, sector
,
1623 iosize
, page_offset
, bdev
,
1624 end_bio_extent_writepage
);
1629 page_offset
+= iosize
;
1633 WARN_ON(test_range_bit(tree
, start
, page_end
, EXTENT_DIRTY
, 0));
1634 unlock_extent(tree
, start
, page_end
, GFP_NOFS
);
1638 EXPORT_SYMBOL(extent_write_full_page
);
1641 * basic invalidatepage code, this waits on any locked or writeback
1642 * ranges corresponding to the page, and then deletes any extent state
1643 * records from the tree
1645 int extent_invalidatepage(struct extent_map_tree
*tree
,
1646 struct page
*page
, unsigned long offset
)
1648 u64 start
= (page
->index
<< PAGE_CACHE_SHIFT
);
1649 u64 end
= start
+ PAGE_CACHE_SIZE
- 1;
1650 size_t blocksize
= page
->mapping
->host
->i_sb
->s_blocksize
;
1652 start
+= (offset
+ blocksize
-1) & ~(blocksize
- 1);
1656 lock_extent(tree
, start
, end
, GFP_NOFS
);
1657 wait_on_extent_writeback(tree
, start
, end
);
1658 clear_extent_bit(tree
, start
, end
,
1659 EXTENT_LOCKED
| EXTENT_DIRTY
| EXTENT_DELALLOC
,
1663 EXPORT_SYMBOL(extent_invalidatepage
);
1666 * simple commit_write call, set_range_dirty is used to mark both
1667 * the pages and the extent records as dirty
1669 int extent_commit_write(struct extent_map_tree
*tree
,
1670 struct inode
*inode
, struct page
*page
,
1671 unsigned from
, unsigned to
)
1673 loff_t pos
= ((loff_t
)page
->index
<< PAGE_CACHE_SHIFT
) + to
;
1675 set_page_extent_mapped(page
);
1676 set_page_dirty(page
);
1678 if (pos
> inode
->i_size
) {
1679 i_size_write(inode
, pos
);
1680 mark_inode_dirty(inode
);
1684 EXPORT_SYMBOL(extent_commit_write
);
1686 int extent_prepare_write(struct extent_map_tree
*tree
,
1687 struct inode
*inode
, struct page
*page
,
1688 unsigned from
, unsigned to
, get_extent_t
*get_extent
)
1690 u64 page_start
= page
->index
<< PAGE_CACHE_SHIFT
;
1691 u64 page_end
= page_start
+ PAGE_CACHE_SIZE
- 1;
1693 u64 orig_block_start
;
1696 struct extent_map
*em
;
1697 unsigned blocksize
= 1 << inode
->i_blkbits
;
1698 size_t page_offset
= 0;
1699 size_t block_off_start
;
1700 size_t block_off_end
;
1706 set_page_extent_mapped(page
);
1708 block_start
= (page_start
+ from
) & ~((u64
)blocksize
- 1);
1709 block_end
= (page_start
+ to
- 1) | (blocksize
- 1);
1710 orig_block_start
= block_start
;
1712 lock_extent(tree
, page_start
, page_end
, GFP_NOFS
);
1713 while(block_start
<= block_end
) {
1714 em
= get_extent(inode
, page
, page_offset
, block_start
,
1716 if (IS_ERR(em
) || !em
) {
1719 cur_end
= min(block_end
, em
->end
);
1720 block_off_start
= block_start
& (PAGE_CACHE_SIZE
- 1);
1721 block_off_end
= block_off_start
+ blocksize
;
1722 isnew
= clear_extent_new(tree
, block_start
, cur_end
, GFP_NOFS
);
1724 if (!PageUptodate(page
) && isnew
&&
1725 (block_off_end
> to
|| block_off_start
< from
)) {
1728 kaddr
= kmap_atomic(page
, KM_USER0
);
1729 if (block_off_end
> to
)
1730 memset(kaddr
+ to
, 0, block_off_end
- to
);
1731 if (block_off_start
< from
)
1732 memset(kaddr
+ block_off_start
, 0,
1733 from
- block_off_start
);
1734 flush_dcache_page(page
);
1735 kunmap_atomic(kaddr
, KM_USER0
);
1737 if (!isnew
&& !PageUptodate(page
) &&
1738 (block_off_end
> to
|| block_off_start
< from
) &&
1739 !test_range_bit(tree
, block_start
, cur_end
,
1740 EXTENT_UPTODATE
, 1)) {
1742 u64 extent_offset
= block_start
- em
->start
;
1744 sector
= (em
->block_start
+ extent_offset
) >> 9;
1745 iosize
= (cur_end
- block_start
+ blocksize
- 1) &
1746 ~((u64
)blocksize
- 1);
1748 * we've already got the extent locked, but we
1749 * need to split the state such that our end_bio
1750 * handler can clear the lock.
1752 set_extent_bit(tree
, block_start
,
1753 block_start
+ iosize
- 1,
1754 EXTENT_LOCKED
, 0, NULL
, GFP_NOFS
);
1755 ret
= submit_extent_page(READ
, tree
, page
,
1756 sector
, iosize
, page_offset
, em
->bdev
,
1757 end_bio_extent_preparewrite
);
1759 block_start
= block_start
+ iosize
;
1761 set_extent_uptodate(tree
, block_start
, cur_end
,
1763 unlock_extent(tree
, block_start
, cur_end
, GFP_NOFS
);
1764 block_start
= cur_end
+ 1;
1766 page_offset
= block_start
& (PAGE_CACHE_SIZE
- 1);
1767 free_extent_map(em
);
1770 wait_extent_bit(tree
, orig_block_start
,
1771 block_end
, EXTENT_LOCKED
);
1773 check_page_uptodate(tree
, page
);
1775 /* FIXME, zero out newly allocated blocks on error */
1778 EXPORT_SYMBOL(extent_prepare_write
);
1781 * a helper for releasepage. As long as there are no locked extents
1782 * in the range corresponding to the page, both state records and extent
1783 * map records are removed
1785 int try_release_extent_mapping(struct extent_map_tree
*tree
, struct page
*page
)
1787 struct extent_map
*em
;
1788 u64 start
= page
->index
<< PAGE_CACHE_SHIFT
;
1789 u64 end
= start
+ PAGE_CACHE_SIZE
- 1;
1790 u64 orig_start
= start
;
1793 while (start
<= end
) {
1794 em
= lookup_extent_mapping(tree
, start
, end
);
1795 if (!em
|| IS_ERR(em
))
1797 if (!test_range_bit(tree
, em
->start
, em
->end
,
1798 EXTENT_LOCKED
, 0)) {
1799 remove_extent_mapping(tree
, em
);
1800 /* once for the rb tree */
1801 free_extent_map(em
);
1803 start
= em
->end
+ 1;
1805 free_extent_map(em
);
1807 if (test_range_bit(tree
, orig_start
, end
, EXTENT_LOCKED
, 0))
1810 clear_extent_bit(tree
, orig_start
, end
, EXTENT_UPTODATE
,
1814 EXPORT_SYMBOL(try_release_extent_mapping
);
1816 sector_t
extent_bmap(struct address_space
*mapping
, sector_t iblock
,
1817 get_extent_t
*get_extent
)
1819 struct inode
*inode
= mapping
->host
;
1820 u64 start
= iblock
<< inode
->i_blkbits
;
1821 u64 end
= start
+ (1 << inode
->i_blkbits
) - 1;
1822 struct extent_map
*em
;
1824 em
= get_extent(inode
, NULL
, 0, start
, end
, 0);
1825 if (!em
|| IS_ERR(em
))
1828 // XXX(hch): block 0 is valid in some cases, e.g. XFS RT device
1829 if (em
->block_start
== EXTENT_MAP_INLINE
||
1830 em
->block_start
== 0)
1833 return (em
->block_start
+ start
- em
->start
) >> inode
->i_blkbits
;