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1#include <linux/bitops.h>
2#include <linux/slab.h>
3#include <linux/bio.h>
4#include <linux/mm.h>
5#include <linux/pagemap.h>
6#include <linux/page-flags.h>
7#include <linux/module.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"
17#include "compat.h"
18#include "ctree.h"
19#include "btrfs_inode.h"
20#include "volumes.h"
21#include "check-integrity.h"
22#include "locking.h"
23#include "rcu-string.h"
24
25static struct kmem_cache *extent_state_cache;
26static struct kmem_cache *extent_buffer_cache;
27
28static LIST_HEAD(buffers);
29static LIST_HEAD(states);
30
31#define LEAK_DEBUG 0
32#if LEAK_DEBUG
33static DEFINE_SPINLOCK(leak_lock);
34#endif
35
36#define BUFFER_LRU_MAX 64
37
38struct tree_entry {
39 u64 start;
40 u64 end;
41 struct rb_node rb_node;
42};
43
44struct extent_page_data {
45 struct bio *bio;
46 struct extent_io_tree *tree;
47 get_extent_t *get_extent;
48
49 /* tells writepage not to lock the state bits for this range
50 * it still does the unlocking
51 */
52 unsigned int extent_locked:1;
53
54 /* tells the submit_bio code to use a WRITE_SYNC */
55 unsigned int sync_io:1;
56};
57
58static noinline void flush_write_bio(void *data);
59static inline struct btrfs_fs_info *
60tree_fs_info(struct extent_io_tree *tree)
61{
62 return btrfs_sb(tree->mapping->host->i_sb);
63}
64
65int __init extent_io_init(void)
66{
67 extent_state_cache = kmem_cache_create("extent_state",
68 sizeof(struct extent_state), 0,
69 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
70 if (!extent_state_cache)
71 return -ENOMEM;
72
73 extent_buffer_cache = kmem_cache_create("extent_buffers",
74 sizeof(struct extent_buffer), 0,
75 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
76 if (!extent_buffer_cache)
77 goto free_state_cache;
78 return 0;
79
80free_state_cache:
81 kmem_cache_destroy(extent_state_cache);
82 return -ENOMEM;
83}
84
85void extent_io_exit(void)
86{
87 struct extent_state *state;
88 struct extent_buffer *eb;
89
90 while (!list_empty(&states)) {
91 state = list_entry(states.next, struct extent_state, leak_list);
92 printk(KERN_ERR "btrfs state leak: start %llu end %llu "
93 "state %lu in tree %p refs %d\n",
94 (unsigned long long)state->start,
95 (unsigned long long)state->end,
96 state->state, state->tree, atomic_read(&state->refs));
97 list_del(&state->leak_list);
98 kmem_cache_free(extent_state_cache, state);
99
100 }
101
102 while (!list_empty(&buffers)) {
103 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
104 printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
105 "refs %d\n", (unsigned long long)eb->start,
106 eb->len, atomic_read(&eb->refs));
107 list_del(&eb->leak_list);
108 kmem_cache_free(extent_buffer_cache, eb);
109 }
110 if (extent_state_cache)
111 kmem_cache_destroy(extent_state_cache);
112 if (extent_buffer_cache)
113 kmem_cache_destroy(extent_buffer_cache);
114}
115
116void extent_io_tree_init(struct extent_io_tree *tree,
117 struct address_space *mapping)
118{
119 tree->state = RB_ROOT;
120 INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
121 tree->ops = NULL;
122 tree->dirty_bytes = 0;
123 spin_lock_init(&tree->lock);
124 spin_lock_init(&tree->buffer_lock);
125 tree->mapping = mapping;
126}
127
128static struct extent_state *alloc_extent_state(gfp_t mask)
129{
130 struct extent_state *state;
131#if LEAK_DEBUG
132 unsigned long flags;
133#endif
134
135 state = kmem_cache_alloc(extent_state_cache, mask);
136 if (!state)
137 return state;
138 state->state = 0;
139 state->private = 0;
140 state->tree = NULL;
141#if LEAK_DEBUG
142 spin_lock_irqsave(&leak_lock, flags);
143 list_add(&state->leak_list, &states);
144 spin_unlock_irqrestore(&leak_lock, flags);
145#endif
146 atomic_set(&state->refs, 1);
147 init_waitqueue_head(&state->wq);
148 trace_alloc_extent_state(state, mask, _RET_IP_);
149 return state;
150}
151
152void free_extent_state(struct extent_state *state)
153{
154 if (!state)
155 return;
156 if (atomic_dec_and_test(&state->refs)) {
157#if LEAK_DEBUG
158 unsigned long flags;
159#endif
160 WARN_ON(state->tree);
161#if LEAK_DEBUG
162 spin_lock_irqsave(&leak_lock, flags);
163 list_del(&state->leak_list);
164 spin_unlock_irqrestore(&leak_lock, flags);
165#endif
166 trace_free_extent_state(state, _RET_IP_);
167 kmem_cache_free(extent_state_cache, state);
168 }
169}
170
171static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
172 struct rb_node *node)
173{
174 struct rb_node **p = &root->rb_node;
175 struct rb_node *parent = NULL;
176 struct tree_entry *entry;
177
178 while (*p) {
179 parent = *p;
180 entry = rb_entry(parent, struct tree_entry, rb_node);
181
182 if (offset < entry->start)
183 p = &(*p)->rb_left;
184 else if (offset > entry->end)
185 p = &(*p)->rb_right;
186 else
187 return parent;
188 }
189
190 rb_link_node(node, parent, p);
191 rb_insert_color(node, root);
192 return NULL;
193}
194
195static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
196 struct rb_node **prev_ret,
197 struct rb_node **next_ret)
198{
199 struct rb_root *root = &tree->state;
200 struct rb_node *n = root->rb_node;
201 struct rb_node *prev = NULL;
202 struct rb_node *orig_prev = NULL;
203 struct tree_entry *entry;
204 struct tree_entry *prev_entry = NULL;
205
206 while (n) {
207 entry = rb_entry(n, struct tree_entry, rb_node);
208 prev = n;
209 prev_entry = entry;
210
211 if (offset < entry->start)
212 n = n->rb_left;
213 else if (offset > entry->end)
214 n = n->rb_right;
215 else
216 return n;
217 }
218
219 if (prev_ret) {
220 orig_prev = prev;
221 while (prev && offset > prev_entry->end) {
222 prev = rb_next(prev);
223 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
224 }
225 *prev_ret = prev;
226 prev = orig_prev;
227 }
228
229 if (next_ret) {
230 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
231 while (prev && offset < prev_entry->start) {
232 prev = rb_prev(prev);
233 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
234 }
235 *next_ret = prev;
236 }
237 return NULL;
238}
239
240static inline struct rb_node *tree_search(struct extent_io_tree *tree,
241 u64 offset)
242{
243 struct rb_node *prev = NULL;
244 struct rb_node *ret;
245
246 ret = __etree_search(tree, offset, &prev, NULL);
247 if (!ret)
248 return prev;
249 return ret;
250}
251
252static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
253 struct extent_state *other)
254{
255 if (tree->ops && tree->ops->merge_extent_hook)
256 tree->ops->merge_extent_hook(tree->mapping->host, new,
257 other);
258}
259
260/*
261 * utility function to look for merge candidates inside a given range.
262 * Any extents with matching state are merged together into a single
263 * extent in the tree. Extents with EXTENT_IO in their state field
264 * are not merged because the end_io handlers need to be able to do
265 * operations on them without sleeping (or doing allocations/splits).
266 *
267 * This should be called with the tree lock held.
268 */
269static void merge_state(struct extent_io_tree *tree,
270 struct extent_state *state)
271{
272 struct extent_state *other;
273 struct rb_node *other_node;
274
275 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
276 return;
277
278 other_node = rb_prev(&state->rb_node);
279 if (other_node) {
280 other = rb_entry(other_node, struct extent_state, rb_node);
281 if (other->end == state->start - 1 &&
282 other->state == state->state) {
283 merge_cb(tree, state, other);
284 state->start = other->start;
285 other->tree = NULL;
286 rb_erase(&other->rb_node, &tree->state);
287 free_extent_state(other);
288 }
289 }
290 other_node = rb_next(&state->rb_node);
291 if (other_node) {
292 other = rb_entry(other_node, struct extent_state, rb_node);
293 if (other->start == state->end + 1 &&
294 other->state == state->state) {
295 merge_cb(tree, state, other);
296 state->end = other->end;
297 other->tree = NULL;
298 rb_erase(&other->rb_node, &tree->state);
299 free_extent_state(other);
300 }
301 }
302}
303
304static void set_state_cb(struct extent_io_tree *tree,
305 struct extent_state *state, int *bits)
306{
307 if (tree->ops && tree->ops->set_bit_hook)
308 tree->ops->set_bit_hook(tree->mapping->host, state, bits);
309}
310
311static void clear_state_cb(struct extent_io_tree *tree,
312 struct extent_state *state, int *bits)
313{
314 if (tree->ops && tree->ops->clear_bit_hook)
315 tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
316}
317
318static void set_state_bits(struct extent_io_tree *tree,
319 struct extent_state *state, int *bits);
320
321/*
322 * insert an extent_state struct into the tree. 'bits' are set on the
323 * struct before it is inserted.
324 *
325 * This may return -EEXIST if the extent is already there, in which case the
326 * state struct is freed.
327 *
328 * The tree lock is not taken internally. This is a utility function and
329 * probably isn't what you want to call (see set/clear_extent_bit).
330 */
331static int insert_state(struct extent_io_tree *tree,
332 struct extent_state *state, u64 start, u64 end,
333 int *bits)
334{
335 struct rb_node *node;
336
337 if (end < start) {
338 printk(KERN_ERR "btrfs end < start %llu %llu\n",
339 (unsigned long long)end,
340 (unsigned long long)start);
341 WARN_ON(1);
342 }
343 state->start = start;
344 state->end = end;
345
346 set_state_bits(tree, state, bits);
347
348 node = tree_insert(&tree->state, end, &state->rb_node);
349 if (node) {
350 struct extent_state *found;
351 found = rb_entry(node, struct extent_state, rb_node);
352 printk(KERN_ERR "btrfs found node %llu %llu on insert of "
353 "%llu %llu\n", (unsigned long long)found->start,
354 (unsigned long long)found->end,
355 (unsigned long long)start, (unsigned long long)end);
356 return -EEXIST;
357 }
358 state->tree = tree;
359 merge_state(tree, state);
360 return 0;
361}
362
363static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
364 u64 split)
365{
366 if (tree->ops && tree->ops->split_extent_hook)
367 tree->ops->split_extent_hook(tree->mapping->host, orig, split);
368}
369
370/*
371 * split a given extent state struct in two, inserting the preallocated
372 * struct 'prealloc' as the newly created second half. 'split' indicates an
373 * offset inside 'orig' where it should be split.
374 *
375 * Before calling,
376 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
377 * are two extent state structs in the tree:
378 * prealloc: [orig->start, split - 1]
379 * orig: [ split, orig->end ]
380 *
381 * The tree locks are not taken by this function. They need to be held
382 * by the caller.
383 */
384static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
385 struct extent_state *prealloc, u64 split)
386{
387 struct rb_node *node;
388
389 split_cb(tree, orig, split);
390
391 prealloc->start = orig->start;
392 prealloc->end = split - 1;
393 prealloc->state = orig->state;
394 orig->start = split;
395
396 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
397 if (node) {
398 free_extent_state(prealloc);
399 return -EEXIST;
400 }
401 prealloc->tree = tree;
402 return 0;
403}
404
405static struct extent_state *next_state(struct extent_state *state)
406{
407 struct rb_node *next = rb_next(&state->rb_node);
408 if (next)
409 return rb_entry(next, struct extent_state, rb_node);
410 else
411 return NULL;
412}
413
414/*
415 * utility function to clear some bits in an extent state struct.
416 * it will optionally wake up any one waiting on this state (wake == 1).
417 *
418 * If no bits are set on the state struct after clearing things, the
419 * struct is freed and removed from the tree
420 */
421static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
422 struct extent_state *state,
423 int *bits, int wake)
424{
425 struct extent_state *next;
426 int bits_to_clear = *bits & ~EXTENT_CTLBITS;
427
428 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
429 u64 range = state->end - state->start + 1;
430 WARN_ON(range > tree->dirty_bytes);
431 tree->dirty_bytes -= range;
432 }
433 clear_state_cb(tree, state, bits);
434 state->state &= ~bits_to_clear;
435 if (wake)
436 wake_up(&state->wq);
437 if (state->state == 0) {
438 next = next_state(state);
439 if (state->tree) {
440 rb_erase(&state->rb_node, &tree->state);
441 state->tree = NULL;
442 free_extent_state(state);
443 } else {
444 WARN_ON(1);
445 }
446 } else {
447 merge_state(tree, state);
448 next = next_state(state);
449 }
450 return next;
451}
452
453static struct extent_state *
454alloc_extent_state_atomic(struct extent_state *prealloc)
455{
456 if (!prealloc)
457 prealloc = alloc_extent_state(GFP_ATOMIC);
458
459 return prealloc;
460}
461
462void extent_io_tree_panic(struct extent_io_tree *tree, int err)
463{
464 btrfs_panic(tree_fs_info(tree), err, "Locking error: "
465 "Extent tree was modified by another "
466 "thread while locked.");
467}
468
469/*
470 * clear some bits on a range in the tree. This may require splitting
471 * or inserting elements in the tree, so the gfp mask is used to
472 * indicate which allocations or sleeping are allowed.
473 *
474 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
475 * the given range from the tree regardless of state (ie for truncate).
476 *
477 * the range [start, end] is inclusive.
478 *
479 * This takes the tree lock, and returns 0 on success and < 0 on error.
480 */
481int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
482 int bits, int wake, int delete,
483 struct extent_state **cached_state,
484 gfp_t mask)
485{
486 struct extent_state *state;
487 struct extent_state *cached;
488 struct extent_state *prealloc = NULL;
489 struct rb_node *node;
490 u64 last_end;
491 int err;
492 int clear = 0;
493
494 if (delete)
495 bits |= ~EXTENT_CTLBITS;
496 bits |= EXTENT_FIRST_DELALLOC;
497
498 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
499 clear = 1;
500again:
501 if (!prealloc && (mask & __GFP_WAIT)) {
502 prealloc = alloc_extent_state(mask);
503 if (!prealloc)
504 return -ENOMEM;
505 }
506
507 spin_lock(&tree->lock);
508 if (cached_state) {
509 cached = *cached_state;
510
511 if (clear) {
512 *cached_state = NULL;
513 cached_state = NULL;
514 }
515
516 if (cached && cached->tree && cached->start <= start &&
517 cached->end > start) {
518 if (clear)
519 atomic_dec(&cached->refs);
520 state = cached;
521 goto hit_next;
522 }
523 if (clear)
524 free_extent_state(cached);
525 }
526 /*
527 * this search will find the extents that end after
528 * our range starts
529 */
530 node = tree_search(tree, start);
531 if (!node)
532 goto out;
533 state = rb_entry(node, struct extent_state, rb_node);
534hit_next:
535 if (state->start > end)
536 goto out;
537 WARN_ON(state->end < start);
538 last_end = state->end;
539
540 /* the state doesn't have the wanted bits, go ahead */
541 if (!(state->state & bits)) {
542 state = next_state(state);
543 goto next;
544 }
545
546 /*
547 * | ---- desired range ---- |
548 * | state | or
549 * | ------------- state -------------- |
550 *
551 * We need to split the extent we found, and may flip
552 * bits on second half.
553 *
554 * If the extent we found extends past our range, we
555 * just split and search again. It'll get split again
556 * the next time though.
557 *
558 * If the extent we found is inside our range, we clear
559 * the desired bit on it.
560 */
561
562 if (state->start < start) {
563 prealloc = alloc_extent_state_atomic(prealloc);
564 BUG_ON(!prealloc);
565 err = split_state(tree, state, prealloc, start);
566 if (err)
567 extent_io_tree_panic(tree, err);
568
569 prealloc = NULL;
570 if (err)
571 goto out;
572 if (state->end <= end) {
573 state = clear_state_bit(tree, state, &bits, wake);
574 goto next;
575 }
576 goto search_again;
577 }
578 /*
579 * | ---- desired range ---- |
580 * | state |
581 * We need to split the extent, and clear the bit
582 * on the first half
583 */
584 if (state->start <= end && state->end > end) {
585 prealloc = alloc_extent_state_atomic(prealloc);
586 BUG_ON(!prealloc);
587 err = split_state(tree, state, prealloc, end + 1);
588 if (err)
589 extent_io_tree_panic(tree, err);
590
591 if (wake)
592 wake_up(&state->wq);
593
594 clear_state_bit(tree, prealloc, &bits, wake);
595
596 prealloc = NULL;
597 goto out;
598 }
599
600 state = clear_state_bit(tree, state, &bits, wake);
601next:
602 if (last_end == (u64)-1)
603 goto out;
604 start = last_end + 1;
605 if (start <= end && state && !need_resched())
606 goto hit_next;
607 goto search_again;
608
609out:
610 spin_unlock(&tree->lock);
611 if (prealloc)
612 free_extent_state(prealloc);
613
614 return 0;
615
616search_again:
617 if (start > end)
618 goto out;
619 spin_unlock(&tree->lock);
620 if (mask & __GFP_WAIT)
621 cond_resched();
622 goto again;
623}
624
625static void wait_on_state(struct extent_io_tree *tree,
626 struct extent_state *state)
627 __releases(tree->lock)
628 __acquires(tree->lock)
629{
630 DEFINE_WAIT(wait);
631 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
632 spin_unlock(&tree->lock);
633 schedule();
634 spin_lock(&tree->lock);
635 finish_wait(&state->wq, &wait);
636}
637
638/*
639 * waits for one or more bits to clear on a range in the state tree.
640 * The range [start, end] is inclusive.
641 * The tree lock is taken by this function
642 */
643void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
644{
645 struct extent_state *state;
646 struct rb_node *node;
647
648 spin_lock(&tree->lock);
649again:
650 while (1) {
651 /*
652 * this search will find all the extents that end after
653 * our range starts
654 */
655 node = tree_search(tree, start);
656 if (!node)
657 break;
658
659 state = rb_entry(node, struct extent_state, rb_node);
660
661 if (state->start > end)
662 goto out;
663
664 if (state->state & bits) {
665 start = state->start;
666 atomic_inc(&state->refs);
667 wait_on_state(tree, state);
668 free_extent_state(state);
669 goto again;
670 }
671 start = state->end + 1;
672
673 if (start > end)
674 break;
675
676 cond_resched_lock(&tree->lock);
677 }
678out:
679 spin_unlock(&tree->lock);
680}
681
682static void set_state_bits(struct extent_io_tree *tree,
683 struct extent_state *state,
684 int *bits)
685{
686 int bits_to_set = *bits & ~EXTENT_CTLBITS;
687
688 set_state_cb(tree, state, bits);
689 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
690 u64 range = state->end - state->start + 1;
691 tree->dirty_bytes += range;
692 }
693 state->state |= bits_to_set;
694}
695
696static void cache_state(struct extent_state *state,
697 struct extent_state **cached_ptr)
698{
699 if (cached_ptr && !(*cached_ptr)) {
700 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
701 *cached_ptr = state;
702 atomic_inc(&state->refs);
703 }
704 }
705}
706
707static void uncache_state(struct extent_state **cached_ptr)
708{
709 if (cached_ptr && (*cached_ptr)) {
710 struct extent_state *state = *cached_ptr;
711 *cached_ptr = NULL;
712 free_extent_state(state);
713 }
714}
715
716/*
717 * set some bits on a range in the tree. This may require allocations or
718 * sleeping, so the gfp mask is used to indicate what is allowed.
719 *
720 * If any of the exclusive bits are set, this will fail with -EEXIST if some
721 * part of the range already has the desired bits set. The start of the
722 * existing range is returned in failed_start in this case.
723 *
724 * [start, end] is inclusive This takes the tree lock.
725 */
726
727static int __must_check
728__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
729 int bits, int exclusive_bits, u64 *failed_start,
730 struct extent_state **cached_state, gfp_t mask)
731{
732 struct extent_state *state;
733 struct extent_state *prealloc = NULL;
734 struct rb_node *node;
735 int err = 0;
736 u64 last_start;
737 u64 last_end;
738
739 bits |= EXTENT_FIRST_DELALLOC;
740again:
741 if (!prealloc && (mask & __GFP_WAIT)) {
742 prealloc = alloc_extent_state(mask);
743 BUG_ON(!prealloc);
744 }
745
746 spin_lock(&tree->lock);
747 if (cached_state && *cached_state) {
748 state = *cached_state;
749 if (state->start <= start && state->end > start &&
750 state->tree) {
751 node = &state->rb_node;
752 goto hit_next;
753 }
754 }
755 /*
756 * this search will find all the extents that end after
757 * our range starts.
758 */
759 node = tree_search(tree, start);
760 if (!node) {
761 prealloc = alloc_extent_state_atomic(prealloc);
762 BUG_ON(!prealloc);
763 err = insert_state(tree, prealloc, start, end, &bits);
764 if (err)
765 extent_io_tree_panic(tree, err);
766
767 prealloc = NULL;
768 goto out;
769 }
770 state = rb_entry(node, struct extent_state, rb_node);
771hit_next:
772 last_start = state->start;
773 last_end = state->end;
774
775 /*
776 * | ---- desired range ---- |
777 * | state |
778 *
779 * Just lock what we found and keep going
780 */
781 if (state->start == start && state->end <= end) {
782 if (state->state & exclusive_bits) {
783 *failed_start = state->start;
784 err = -EEXIST;
785 goto out;
786 }
787
788 set_state_bits(tree, state, &bits);
789 cache_state(state, cached_state);
790 merge_state(tree, state);
791 if (last_end == (u64)-1)
792 goto out;
793 start = last_end + 1;
794 state = next_state(state);
795 if (start < end && state && state->start == start &&
796 !need_resched())
797 goto hit_next;
798 goto search_again;
799 }
800
801 /*
802 * | ---- desired range ---- |
803 * | state |
804 * or
805 * | ------------- state -------------- |
806 *
807 * We need to split the extent we found, and may flip bits on
808 * second half.
809 *
810 * If the extent we found extends past our
811 * range, we just split and search again. It'll get split
812 * again the next time though.
813 *
814 * If the extent we found is inside our range, we set the
815 * desired bit on it.
816 */
817 if (state->start < start) {
818 if (state->state & exclusive_bits) {
819 *failed_start = start;
820 err = -EEXIST;
821 goto out;
822 }
823
824 prealloc = alloc_extent_state_atomic(prealloc);
825 BUG_ON(!prealloc);
826 err = split_state(tree, state, prealloc, start);
827 if (err)
828 extent_io_tree_panic(tree, err);
829
830 prealloc = NULL;
831 if (err)
832 goto out;
833 if (state->end <= end) {
834 set_state_bits(tree, state, &bits);
835 cache_state(state, cached_state);
836 merge_state(tree, state);
837 if (last_end == (u64)-1)
838 goto out;
839 start = last_end + 1;
840 state = next_state(state);
841 if (start < end && state && state->start == start &&
842 !need_resched())
843 goto hit_next;
844 }
845 goto search_again;
846 }
847 /*
848 * | ---- desired range ---- |
849 * | state | or | state |
850 *
851 * There's a hole, we need to insert something in it and
852 * ignore the extent we found.
853 */
854 if (state->start > start) {
855 u64 this_end;
856 if (end < last_start)
857 this_end = end;
858 else
859 this_end = last_start - 1;
860
861 prealloc = alloc_extent_state_atomic(prealloc);
862 BUG_ON(!prealloc);
863
864 /*
865 * Avoid to free 'prealloc' if it can be merged with
866 * the later extent.
867 */
868 err = insert_state(tree, prealloc, start, this_end,
869 &bits);
870 if (err)
871 extent_io_tree_panic(tree, err);
872
873 cache_state(prealloc, cached_state);
874 prealloc = NULL;
875 start = this_end + 1;
876 goto search_again;
877 }
878 /*
879 * | ---- desired range ---- |
880 * | state |
881 * We need to split the extent, and set the bit
882 * on the first half
883 */
884 if (state->start <= end && state->end > end) {
885 if (state->state & exclusive_bits) {
886 *failed_start = start;
887 err = -EEXIST;
888 goto out;
889 }
890
891 prealloc = alloc_extent_state_atomic(prealloc);
892 BUG_ON(!prealloc);
893 err = split_state(tree, state, prealloc, end + 1);
894 if (err)
895 extent_io_tree_panic(tree, err);
896
897 set_state_bits(tree, prealloc, &bits);
898 cache_state(prealloc, cached_state);
899 merge_state(tree, prealloc);
900 prealloc = NULL;
901 goto out;
902 }
903
904 goto search_again;
905
906out:
907 spin_unlock(&tree->lock);
908 if (prealloc)
909 free_extent_state(prealloc);
910
911 return err;
912
913search_again:
914 if (start > end)
915 goto out;
916 spin_unlock(&tree->lock);
917 if (mask & __GFP_WAIT)
918 cond_resched();
919 goto again;
920}
921
922int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits,
923 u64 *failed_start, struct extent_state **cached_state,
924 gfp_t mask)
925{
926 return __set_extent_bit(tree, start, end, bits, 0, failed_start,
927 cached_state, mask);
928}
929
930
931/**
932 * convert_extent - convert all bits in a given range from one bit to another
933 * @tree: the io tree to search
934 * @start: the start offset in bytes
935 * @end: the end offset in bytes (inclusive)
936 * @bits: the bits to set in this range
937 * @clear_bits: the bits to clear in this range
938 * @mask: the allocation mask
939 *
940 * This will go through and set bits for the given range. If any states exist
941 * already in this range they are set with the given bit and cleared of the
942 * clear_bits. This is only meant to be used by things that are mergeable, ie
943 * converting from say DELALLOC to DIRTY. This is not meant to be used with
944 * boundary bits like LOCK.
945 */
946int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
947 int bits, int clear_bits, gfp_t mask)
948{
949 struct extent_state *state;
950 struct extent_state *prealloc = NULL;
951 struct rb_node *node;
952 int err = 0;
953 u64 last_start;
954 u64 last_end;
955
956again:
957 if (!prealloc && (mask & __GFP_WAIT)) {
958 prealloc = alloc_extent_state(mask);
959 if (!prealloc)
960 return -ENOMEM;
961 }
962
963 spin_lock(&tree->lock);
964 /*
965 * this search will find all the extents that end after
966 * our range starts.
967 */
968 node = tree_search(tree, start);
969 if (!node) {
970 prealloc = alloc_extent_state_atomic(prealloc);
971 if (!prealloc) {
972 err = -ENOMEM;
973 goto out;
974 }
975 err = insert_state(tree, prealloc, start, end, &bits);
976 prealloc = NULL;
977 if (err)
978 extent_io_tree_panic(tree, err);
979 goto out;
980 }
981 state = rb_entry(node, struct extent_state, rb_node);
982hit_next:
983 last_start = state->start;
984 last_end = state->end;
985
986 /*
987 * | ---- desired range ---- |
988 * | state |
989 *
990 * Just lock what we found and keep going
991 */
992 if (state->start == start && state->end <= end) {
993 set_state_bits(tree, state, &bits);
994 state = clear_state_bit(tree, state, &clear_bits, 0);
995 if (last_end == (u64)-1)
996 goto out;
997 start = last_end + 1;
998 if (start < end && state && state->start == start &&
999 !need_resched())
1000 goto hit_next;
1001 goto search_again;
1002 }
1003
1004 /*
1005 * | ---- desired range ---- |
1006 * | state |
1007 * or
1008 * | ------------- state -------------- |
1009 *
1010 * We need to split the extent we found, and may flip bits on
1011 * second half.
1012 *
1013 * If the extent we found extends past our
1014 * range, we just split and search again. It'll get split
1015 * again the next time though.
1016 *
1017 * If the extent we found is inside our range, we set the
1018 * desired bit on it.
1019 */
1020 if (state->start < start) {
1021 prealloc = alloc_extent_state_atomic(prealloc);
1022 if (!prealloc) {
1023 err = -ENOMEM;
1024 goto out;
1025 }
1026 err = split_state(tree, state, prealloc, start);
1027 if (err)
1028 extent_io_tree_panic(tree, err);
1029 prealloc = NULL;
1030 if (err)
1031 goto out;
1032 if (state->end <= end) {
1033 set_state_bits(tree, state, &bits);
1034 state = clear_state_bit(tree, state, &clear_bits, 0);
1035 if (last_end == (u64)-1)
1036 goto out;
1037 start = last_end + 1;
1038 if (start < end && state && state->start == start &&
1039 !need_resched())
1040 goto hit_next;
1041 }
1042 goto search_again;
1043 }
1044 /*
1045 * | ---- desired range ---- |
1046 * | state | or | state |
1047 *
1048 * There's a hole, we need to insert something in it and
1049 * ignore the extent we found.
1050 */
1051 if (state->start > start) {
1052 u64 this_end;
1053 if (end < last_start)
1054 this_end = end;
1055 else
1056 this_end = last_start - 1;
1057
1058 prealloc = alloc_extent_state_atomic(prealloc);
1059 if (!prealloc) {
1060 err = -ENOMEM;
1061 goto out;
1062 }
1063
1064 /*
1065 * Avoid to free 'prealloc' if it can be merged with
1066 * the later extent.
1067 */
1068 err = insert_state(tree, prealloc, start, this_end,
1069 &bits);
1070 if (err)
1071 extent_io_tree_panic(tree, err);
1072 prealloc = NULL;
1073 start = this_end + 1;
1074 goto search_again;
1075 }
1076 /*
1077 * | ---- desired range ---- |
1078 * | state |
1079 * We need to split the extent, and set the bit
1080 * on the first half
1081 */
1082 if (state->start <= end && state->end > end) {
1083 prealloc = alloc_extent_state_atomic(prealloc);
1084 if (!prealloc) {
1085 err = -ENOMEM;
1086 goto out;
1087 }
1088
1089 err = split_state(tree, state, prealloc, end + 1);
1090 if (err)
1091 extent_io_tree_panic(tree, err);
1092
1093 set_state_bits(tree, prealloc, &bits);
1094 clear_state_bit(tree, prealloc, &clear_bits, 0);
1095 prealloc = NULL;
1096 goto out;
1097 }
1098
1099 goto search_again;
1100
1101out:
1102 spin_unlock(&tree->lock);
1103 if (prealloc)
1104 free_extent_state(prealloc);
1105
1106 return err;
1107
1108search_again:
1109 if (start > end)
1110 goto out;
1111 spin_unlock(&tree->lock);
1112 if (mask & __GFP_WAIT)
1113 cond_resched();
1114 goto again;
1115}
1116
1117/* wrappers around set/clear extent bit */
1118int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
1119 gfp_t mask)
1120{
1121 return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL,
1122 NULL, mask);
1123}
1124
1125int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1126 int bits, gfp_t mask)
1127{
1128 return set_extent_bit(tree, start, end, bits, NULL,
1129 NULL, mask);
1130}
1131
1132int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1133 int bits, gfp_t mask)
1134{
1135 return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
1136}
1137
1138int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
1139 struct extent_state **cached_state, gfp_t mask)
1140{
1141 return set_extent_bit(tree, start, end,
1142 EXTENT_DELALLOC | EXTENT_UPTODATE,
1143 NULL, cached_state, mask);
1144}
1145
1146int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
1147 gfp_t mask)
1148{
1149 return clear_extent_bit(tree, start, end,
1150 EXTENT_DIRTY | EXTENT_DELALLOC |
1151 EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
1152}
1153
1154int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
1155 gfp_t mask)
1156{
1157 return set_extent_bit(tree, start, end, EXTENT_NEW, NULL,
1158 NULL, mask);
1159}
1160
1161int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
1162 struct extent_state **cached_state, gfp_t mask)
1163{
1164 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0,
1165 cached_state, mask);
1166}
1167
1168int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
1169 struct extent_state **cached_state, gfp_t mask)
1170{
1171 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
1172 cached_state, mask);
1173}
1174
1175/*
1176 * either insert or lock state struct between start and end use mask to tell
1177 * us if waiting is desired.
1178 */
1179int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1180 int bits, struct extent_state **cached_state)
1181{
1182 int err;
1183 u64 failed_start;
1184 while (1) {
1185 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
1186 EXTENT_LOCKED, &failed_start,
1187 cached_state, GFP_NOFS);
1188 if (err == -EEXIST) {
1189 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
1190 start = failed_start;
1191 } else
1192 break;
1193 WARN_ON(start > end);
1194 }
1195 return err;
1196}
1197
1198int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1199{
1200 return lock_extent_bits(tree, start, end, 0, NULL);
1201}
1202
1203int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1204{
1205 int err;
1206 u64 failed_start;
1207
1208 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1209 &failed_start, NULL, GFP_NOFS);
1210 if (err == -EEXIST) {
1211 if (failed_start > start)
1212 clear_extent_bit(tree, start, failed_start - 1,
1213 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
1214 return 0;
1215 }
1216 return 1;
1217}
1218
1219int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
1220 struct extent_state **cached, gfp_t mask)
1221{
1222 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
1223 mask);
1224}
1225
1226int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1227{
1228 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1229 GFP_NOFS);
1230}
1231
1232/*
1233 * helper function to set both pages and extents in the tree writeback
1234 */
1235static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1236{
1237 unsigned long index = start >> PAGE_CACHE_SHIFT;
1238 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1239 struct page *page;
1240
1241 while (index <= end_index) {
1242 page = find_get_page(tree->mapping, index);
1243 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1244 set_page_writeback(page);
1245 page_cache_release(page);
1246 index++;
1247 }
1248 return 0;
1249}
1250
1251/* find the first state struct with 'bits' set after 'start', and
1252 * return it. tree->lock must be held. NULL will returned if
1253 * nothing was found after 'start'
1254 */
1255struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
1256 u64 start, int bits)
1257{
1258 struct rb_node *node;
1259 struct extent_state *state;
1260
1261 /*
1262 * this search will find all the extents that end after
1263 * our range starts.
1264 */
1265 node = tree_search(tree, start);
1266 if (!node)
1267 goto out;
1268
1269 while (1) {
1270 state = rb_entry(node, struct extent_state, rb_node);
1271 if (state->end >= start && (state->state & bits))
1272 return state;
1273
1274 node = rb_next(node);
1275 if (!node)
1276 break;
1277 }
1278out:
1279 return NULL;
1280}
1281
1282/*
1283 * find the first offset in the io tree with 'bits' set. zero is
1284 * returned if we find something, and *start_ret and *end_ret are
1285 * set to reflect the state struct that was found.
1286 *
1287 * If nothing was found, 1 is returned. If found something, return 0.
1288 */
1289int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1290 u64 *start_ret, u64 *end_ret, int bits)
1291{
1292 struct extent_state *state;
1293 int ret = 1;
1294
1295 spin_lock(&tree->lock);
1296 state = find_first_extent_bit_state(tree, start, bits);
1297 if (state) {
1298 *start_ret = state->start;
1299 *end_ret = state->end;
1300 ret = 0;
1301 }
1302 spin_unlock(&tree->lock);
1303 return ret;
1304}
1305
1306/*
1307 * find a contiguous range of bytes in the file marked as delalloc, not
1308 * more than 'max_bytes'. start and end are used to return the range,
1309 *
1310 * 1 is returned if we find something, 0 if nothing was in the tree
1311 */
1312static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1313 u64 *start, u64 *end, u64 max_bytes,
1314 struct extent_state **cached_state)
1315{
1316 struct rb_node *node;
1317 struct extent_state *state;
1318 u64 cur_start = *start;
1319 u64 found = 0;
1320 u64 total_bytes = 0;
1321
1322 spin_lock(&tree->lock);
1323
1324 /*
1325 * this search will find all the extents that end after
1326 * our range starts.
1327 */
1328 node = tree_search(tree, cur_start);
1329 if (!node) {
1330 if (!found)
1331 *end = (u64)-1;
1332 goto out;
1333 }
1334
1335 while (1) {
1336 state = rb_entry(node, struct extent_state, rb_node);
1337 if (found && (state->start != cur_start ||
1338 (state->state & EXTENT_BOUNDARY))) {
1339 goto out;
1340 }
1341 if (!(state->state & EXTENT_DELALLOC)) {
1342 if (!found)
1343 *end = state->end;
1344 goto out;
1345 }
1346 if (!found) {
1347 *start = state->start;
1348 *cached_state = state;
1349 atomic_inc(&state->refs);
1350 }
1351 found++;
1352 *end = state->end;
1353 cur_start = state->end + 1;
1354 node = rb_next(node);
1355 if (!node)
1356 break;
1357 total_bytes += state->end - state->start + 1;
1358 if (total_bytes >= max_bytes)
1359 break;
1360 }
1361out:
1362 spin_unlock(&tree->lock);
1363 return found;
1364}
1365
1366static noinline void __unlock_for_delalloc(struct inode *inode,
1367 struct page *locked_page,
1368 u64 start, u64 end)
1369{
1370 int ret;
1371 struct page *pages[16];
1372 unsigned long index = start >> PAGE_CACHE_SHIFT;
1373 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1374 unsigned long nr_pages = end_index - index + 1;
1375 int i;
1376
1377 if (index == locked_page->index && end_index == index)
1378 return;
1379
1380 while (nr_pages > 0) {
1381 ret = find_get_pages_contig(inode->i_mapping, index,
1382 min_t(unsigned long, nr_pages,
1383 ARRAY_SIZE(pages)), pages);
1384 for (i = 0; i < ret; i++) {
1385 if (pages[i] != locked_page)
1386 unlock_page(pages[i]);
1387 page_cache_release(pages[i]);
1388 }
1389 nr_pages -= ret;
1390 index += ret;
1391 cond_resched();
1392 }
1393}
1394
1395static noinline int lock_delalloc_pages(struct inode *inode,
1396 struct page *locked_page,
1397 u64 delalloc_start,
1398 u64 delalloc_end)
1399{
1400 unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
1401 unsigned long start_index = index;
1402 unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
1403 unsigned long pages_locked = 0;
1404 struct page *pages[16];
1405 unsigned long nrpages;
1406 int ret;
1407 int i;
1408
1409 /* the caller is responsible for locking the start index */
1410 if (index == locked_page->index && index == end_index)
1411 return 0;
1412
1413 /* skip the page at the start index */
1414 nrpages = end_index - index + 1;
1415 while (nrpages > 0) {
1416 ret = find_get_pages_contig(inode->i_mapping, index,
1417 min_t(unsigned long,
1418 nrpages, ARRAY_SIZE(pages)), pages);
1419 if (ret == 0) {
1420 ret = -EAGAIN;
1421 goto done;
1422 }
1423 /* now we have an array of pages, lock them all */
1424 for (i = 0; i < ret; i++) {
1425 /*
1426 * the caller is taking responsibility for
1427 * locked_page
1428 */
1429 if (pages[i] != locked_page) {
1430 lock_page(pages[i]);
1431 if (!PageDirty(pages[i]) ||
1432 pages[i]->mapping != inode->i_mapping) {
1433 ret = -EAGAIN;
1434 unlock_page(pages[i]);
1435 page_cache_release(pages[i]);
1436 goto done;
1437 }
1438 }
1439 page_cache_release(pages[i]);
1440 pages_locked++;
1441 }
1442 nrpages -= ret;
1443 index += ret;
1444 cond_resched();
1445 }
1446 ret = 0;
1447done:
1448 if (ret && pages_locked) {
1449 __unlock_for_delalloc(inode, locked_page,
1450 delalloc_start,
1451 ((u64)(start_index + pages_locked - 1)) <<
1452 PAGE_CACHE_SHIFT);
1453 }
1454 return ret;
1455}
1456
1457/*
1458 * find a contiguous range of bytes in the file marked as delalloc, not
1459 * more than 'max_bytes'. start and end are used to return the range,
1460 *
1461 * 1 is returned if we find something, 0 if nothing was in the tree
1462 */
1463static noinline u64 find_lock_delalloc_range(struct inode *inode,
1464 struct extent_io_tree *tree,
1465 struct page *locked_page,
1466 u64 *start, u64 *end,
1467 u64 max_bytes)
1468{
1469 u64 delalloc_start;
1470 u64 delalloc_end;
1471 u64 found;
1472 struct extent_state *cached_state = NULL;
1473 int ret;
1474 int loops = 0;
1475
1476again:
1477 /* step one, find a bunch of delalloc bytes starting at start */
1478 delalloc_start = *start;
1479 delalloc_end = 0;
1480 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1481 max_bytes, &cached_state);
1482 if (!found || delalloc_end <= *start) {
1483 *start = delalloc_start;
1484 *end = delalloc_end;
1485 free_extent_state(cached_state);
1486 return found;
1487 }
1488
1489 /*
1490 * start comes from the offset of locked_page. We have to lock
1491 * pages in order, so we can't process delalloc bytes before
1492 * locked_page
1493 */
1494 if (delalloc_start < *start)
1495 delalloc_start = *start;
1496
1497 /*
1498 * make sure to limit the number of pages we try to lock down
1499 * if we're looping.
1500 */
1501 if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1502 delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
1503
1504 /* step two, lock all the pages after the page that has start */
1505 ret = lock_delalloc_pages(inode, locked_page,
1506 delalloc_start, delalloc_end);
1507 if (ret == -EAGAIN) {
1508 /* some of the pages are gone, lets avoid looping by
1509 * shortening the size of the delalloc range we're searching
1510 */
1511 free_extent_state(cached_state);
1512 if (!loops) {
1513 unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
1514 max_bytes = PAGE_CACHE_SIZE - offset;
1515 loops = 1;
1516 goto again;
1517 } else {
1518 found = 0;
1519 goto out_failed;
1520 }
1521 }
1522 BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
1523
1524 /* step three, lock the state bits for the whole range */
1525 lock_extent_bits(tree, delalloc_start, delalloc_end, 0, &cached_state);
1526
1527 /* then test to make sure it is all still delalloc */
1528 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1529 EXTENT_DELALLOC, 1, cached_state);
1530 if (!ret) {
1531 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1532 &cached_state, GFP_NOFS);
1533 __unlock_for_delalloc(inode, locked_page,
1534 delalloc_start, delalloc_end);
1535 cond_resched();
1536 goto again;
1537 }
1538 free_extent_state(cached_state);
1539 *start = delalloc_start;
1540 *end = delalloc_end;
1541out_failed:
1542 return found;
1543}
1544
1545int extent_clear_unlock_delalloc(struct inode *inode,
1546 struct extent_io_tree *tree,
1547 u64 start, u64 end, struct page *locked_page,
1548 unsigned long op)
1549{
1550 int ret;
1551 struct page *pages[16];
1552 unsigned long index = start >> PAGE_CACHE_SHIFT;
1553 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1554 unsigned long nr_pages = end_index - index + 1;
1555 int i;
1556 int clear_bits = 0;
1557
1558 if (op & EXTENT_CLEAR_UNLOCK)
1559 clear_bits |= EXTENT_LOCKED;
1560 if (op & EXTENT_CLEAR_DIRTY)
1561 clear_bits |= EXTENT_DIRTY;
1562
1563 if (op & EXTENT_CLEAR_DELALLOC)
1564 clear_bits |= EXTENT_DELALLOC;
1565
1566 clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1567 if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
1568 EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
1569 EXTENT_SET_PRIVATE2)))
1570 return 0;
1571
1572 while (nr_pages > 0) {
1573 ret = find_get_pages_contig(inode->i_mapping, index,
1574 min_t(unsigned long,
1575 nr_pages, ARRAY_SIZE(pages)), pages);
1576 for (i = 0; i < ret; i++) {
1577
1578 if (op & EXTENT_SET_PRIVATE2)
1579 SetPagePrivate2(pages[i]);
1580
1581 if (pages[i] == locked_page) {
1582 page_cache_release(pages[i]);
1583 continue;
1584 }
1585 if (op & EXTENT_CLEAR_DIRTY)
1586 clear_page_dirty_for_io(pages[i]);
1587 if (op & EXTENT_SET_WRITEBACK)
1588 set_page_writeback(pages[i]);
1589 if (op & EXTENT_END_WRITEBACK)
1590 end_page_writeback(pages[i]);
1591 if (op & EXTENT_CLEAR_UNLOCK_PAGE)
1592 unlock_page(pages[i]);
1593 page_cache_release(pages[i]);
1594 }
1595 nr_pages -= ret;
1596 index += ret;
1597 cond_resched();
1598 }
1599 return 0;
1600}
1601
1602/*
1603 * count the number of bytes in the tree that have a given bit(s)
1604 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1605 * cached. The total number found is returned.
1606 */
1607u64 count_range_bits(struct extent_io_tree *tree,
1608 u64 *start, u64 search_end, u64 max_bytes,
1609 unsigned long bits, int contig)
1610{
1611 struct rb_node *node;
1612 struct extent_state *state;
1613 u64 cur_start = *start;
1614 u64 total_bytes = 0;
1615 u64 last = 0;
1616 int found = 0;
1617
1618 if (search_end <= cur_start) {
1619 WARN_ON(1);
1620 return 0;
1621 }
1622
1623 spin_lock(&tree->lock);
1624 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1625 total_bytes = tree->dirty_bytes;
1626 goto out;
1627 }
1628 /*
1629 * this search will find all the extents that end after
1630 * our range starts.
1631 */
1632 node = tree_search(tree, cur_start);
1633 if (!node)
1634 goto out;
1635
1636 while (1) {
1637 state = rb_entry(node, struct extent_state, rb_node);
1638 if (state->start > search_end)
1639 break;
1640 if (contig && found && state->start > last + 1)
1641 break;
1642 if (state->end >= cur_start && (state->state & bits) == bits) {
1643 total_bytes += min(search_end, state->end) + 1 -
1644 max(cur_start, state->start);
1645 if (total_bytes >= max_bytes)
1646 break;
1647 if (!found) {
1648 *start = max(cur_start, state->start);
1649 found = 1;
1650 }
1651 last = state->end;
1652 } else if (contig && found) {
1653 break;
1654 }
1655 node = rb_next(node);
1656 if (!node)
1657 break;
1658 }
1659out:
1660 spin_unlock(&tree->lock);
1661 return total_bytes;
1662}
1663
1664/*
1665 * set the private field for a given byte offset in the tree. If there isn't
1666 * an extent_state there already, this does nothing.
1667 */
1668int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1669{
1670 struct rb_node *node;
1671 struct extent_state *state;
1672 int ret = 0;
1673
1674 spin_lock(&tree->lock);
1675 /*
1676 * this search will find all the extents that end after
1677 * our range starts.
1678 */
1679 node = tree_search(tree, start);
1680 if (!node) {
1681 ret = -ENOENT;
1682 goto out;
1683 }
1684 state = rb_entry(node, struct extent_state, rb_node);
1685 if (state->start != start) {
1686 ret = -ENOENT;
1687 goto out;
1688 }
1689 state->private = private;
1690out:
1691 spin_unlock(&tree->lock);
1692 return ret;
1693}
1694
1695int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1696{
1697 struct rb_node *node;
1698 struct extent_state *state;
1699 int ret = 0;
1700
1701 spin_lock(&tree->lock);
1702 /*
1703 * this search will find all the extents that end after
1704 * our range starts.
1705 */
1706 node = tree_search(tree, start);
1707 if (!node) {
1708 ret = -ENOENT;
1709 goto out;
1710 }
1711 state = rb_entry(node, struct extent_state, rb_node);
1712 if (state->start != start) {
1713 ret = -ENOENT;
1714 goto out;
1715 }
1716 *private = state->private;
1717out:
1718 spin_unlock(&tree->lock);
1719 return ret;
1720}
1721
1722/*
1723 * searches a range in the state tree for a given mask.
1724 * If 'filled' == 1, this returns 1 only if every extent in the tree
1725 * has the bits set. Otherwise, 1 is returned if any bit in the
1726 * range is found set.
1727 */
1728int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1729 int bits, int filled, struct extent_state *cached)
1730{
1731 struct extent_state *state = NULL;
1732 struct rb_node *node;
1733 int bitset = 0;
1734
1735 spin_lock(&tree->lock);
1736 if (cached && cached->tree && cached->start <= start &&
1737 cached->end > start)
1738 node = &cached->rb_node;
1739 else
1740 node = tree_search(tree, start);
1741 while (node && start <= end) {
1742 state = rb_entry(node, struct extent_state, rb_node);
1743
1744 if (filled && state->start > start) {
1745 bitset = 0;
1746 break;
1747 }
1748
1749 if (state->start > end)
1750 break;
1751
1752 if (state->state & bits) {
1753 bitset = 1;
1754 if (!filled)
1755 break;
1756 } else if (filled) {
1757 bitset = 0;
1758 break;
1759 }
1760
1761 if (state->end == (u64)-1)
1762 break;
1763
1764 start = state->end + 1;
1765 if (start > end)
1766 break;
1767 node = rb_next(node);
1768 if (!node) {
1769 if (filled)
1770 bitset = 0;
1771 break;
1772 }
1773 }
1774 spin_unlock(&tree->lock);
1775 return bitset;
1776}
1777
1778/*
1779 * helper function to set a given page up to date if all the
1780 * extents in the tree for that page are up to date
1781 */
1782static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1783{
1784 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1785 u64 end = start + PAGE_CACHE_SIZE - 1;
1786 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1787 SetPageUptodate(page);
1788}
1789
1790/*
1791 * helper function to unlock a page if all the extents in the tree
1792 * for that page are unlocked
1793 */
1794static void check_page_locked(struct extent_io_tree *tree, struct page *page)
1795{
1796 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1797 u64 end = start + PAGE_CACHE_SIZE - 1;
1798 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
1799 unlock_page(page);
1800}
1801
1802/*
1803 * helper function to end page writeback if all the extents
1804 * in the tree for that page are done with writeback
1805 */
1806static void check_page_writeback(struct extent_io_tree *tree,
1807 struct page *page)
1808{
1809 end_page_writeback(page);
1810}
1811
1812/*
1813 * When IO fails, either with EIO or csum verification fails, we
1814 * try other mirrors that might have a good copy of the data. This
1815 * io_failure_record is used to record state as we go through all the
1816 * mirrors. If another mirror has good data, the page is set up to date
1817 * and things continue. If a good mirror can't be found, the original
1818 * bio end_io callback is called to indicate things have failed.
1819 */
1820struct io_failure_record {
1821 struct page *page;
1822 u64 start;
1823 u64 len;
1824 u64 logical;
1825 unsigned long bio_flags;
1826 int this_mirror;
1827 int failed_mirror;
1828 int in_validation;
1829};
1830
1831static int free_io_failure(struct inode *inode, struct io_failure_record *rec,
1832 int did_repair)
1833{
1834 int ret;
1835 int err = 0;
1836 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1837
1838 set_state_private(failure_tree, rec->start, 0);
1839 ret = clear_extent_bits(failure_tree, rec->start,
1840 rec->start + rec->len - 1,
1841 EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1842 if (ret)
1843 err = ret;
1844
1845 if (did_repair) {
1846 ret = clear_extent_bits(&BTRFS_I(inode)->io_tree, rec->start,
1847 rec->start + rec->len - 1,
1848 EXTENT_DAMAGED, GFP_NOFS);
1849 if (ret && !err)
1850 err = ret;
1851 }
1852
1853 kfree(rec);
1854 return err;
1855}
1856
1857static void repair_io_failure_callback(struct bio *bio, int err)
1858{
1859 complete(bio->bi_private);
1860}
1861
1862/*
1863 * this bypasses the standard btrfs submit functions deliberately, as
1864 * the standard behavior is to write all copies in a raid setup. here we only
1865 * want to write the one bad copy. so we do the mapping for ourselves and issue
1866 * submit_bio directly.
1867 * to avoid any synchonization issues, wait for the data after writing, which
1868 * actually prevents the read that triggered the error from finishing.
1869 * currently, there can be no more than two copies of every data bit. thus,
1870 * exactly one rewrite is required.
1871 */
1872int repair_io_failure(struct btrfs_mapping_tree *map_tree, u64 start,
1873 u64 length, u64 logical, struct page *page,
1874 int mirror_num)
1875{
1876 struct bio *bio;
1877 struct btrfs_device *dev;
1878 DECLARE_COMPLETION_ONSTACK(compl);
1879 u64 map_length = 0;
1880 u64 sector;
1881 struct btrfs_bio *bbio = NULL;
1882 int ret;
1883
1884 BUG_ON(!mirror_num);
1885
1886 bio = bio_alloc(GFP_NOFS, 1);
1887 if (!bio)
1888 return -EIO;
1889 bio->bi_private = &compl;
1890 bio->bi_end_io = repair_io_failure_callback;
1891 bio->bi_size = 0;
1892 map_length = length;
1893
1894 ret = btrfs_map_block(map_tree, WRITE, logical,
1895 &map_length, &bbio, mirror_num);
1896 if (ret) {
1897 bio_put(bio);
1898 return -EIO;
1899 }
1900 BUG_ON(mirror_num != bbio->mirror_num);
1901 sector = bbio->stripes[mirror_num-1].physical >> 9;
1902 bio->bi_sector = sector;
1903 dev = bbio->stripes[mirror_num-1].dev;
1904 kfree(bbio);
1905 if (!dev || !dev->bdev || !dev->writeable) {
1906 bio_put(bio);
1907 return -EIO;
1908 }
1909 bio->bi_bdev = dev->bdev;
1910 bio_add_page(bio, page, length, start-page_offset(page));
1911 btrfsic_submit_bio(WRITE_SYNC, bio);
1912 wait_for_completion(&compl);
1913
1914 if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
1915 /* try to remap that extent elsewhere? */
1916 bio_put(bio);
1917 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
1918 return -EIO;
1919 }
1920
1921 printk_in_rcu(KERN_INFO "btrfs read error corrected: ino %lu off %llu "
1922 "(dev %s sector %llu)\n", page->mapping->host->i_ino,
1923 start, rcu_str_deref(dev->name), sector);
1924
1925 bio_put(bio);
1926 return 0;
1927}
1928
1929int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb,
1930 int mirror_num)
1931{
1932 struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
1933 u64 start = eb->start;
1934 unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
1935 int ret = 0;
1936
1937 for (i = 0; i < num_pages; i++) {
1938 struct page *p = extent_buffer_page(eb, i);
1939 ret = repair_io_failure(map_tree, start, PAGE_CACHE_SIZE,
1940 start, p, mirror_num);
1941 if (ret)
1942 break;
1943 start += PAGE_CACHE_SIZE;
1944 }
1945
1946 return ret;
1947}
1948
1949/*
1950 * each time an IO finishes, we do a fast check in the IO failure tree
1951 * to see if we need to process or clean up an io_failure_record
1952 */
1953static int clean_io_failure(u64 start, struct page *page)
1954{
1955 u64 private;
1956 u64 private_failure;
1957 struct io_failure_record *failrec;
1958 struct btrfs_mapping_tree *map_tree;
1959 struct extent_state *state;
1960 int num_copies;
1961 int did_repair = 0;
1962 int ret;
1963 struct inode *inode = page->mapping->host;
1964
1965 private = 0;
1966 ret = count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
1967 (u64)-1, 1, EXTENT_DIRTY, 0);
1968 if (!ret)
1969 return 0;
1970
1971 ret = get_state_private(&BTRFS_I(inode)->io_failure_tree, start,
1972 &private_failure);
1973 if (ret)
1974 return 0;
1975
1976 failrec = (struct io_failure_record *)(unsigned long) private_failure;
1977 BUG_ON(!failrec->this_mirror);
1978
1979 if (failrec->in_validation) {
1980 /* there was no real error, just free the record */
1981 pr_debug("clean_io_failure: freeing dummy error at %llu\n",
1982 failrec->start);
1983 did_repair = 1;
1984 goto out;
1985 }
1986
1987 spin_lock(&BTRFS_I(inode)->io_tree.lock);
1988 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
1989 failrec->start,
1990 EXTENT_LOCKED);
1991 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
1992
1993 if (state && state->start == failrec->start) {
1994 map_tree = &BTRFS_I(inode)->root->fs_info->mapping_tree;
1995 num_copies = btrfs_num_copies(map_tree, failrec->logical,
1996 failrec->len);
1997 if (num_copies > 1) {
1998 ret = repair_io_failure(map_tree, start, failrec->len,
1999 failrec->logical, page,
2000 failrec->failed_mirror);
2001 did_repair = !ret;
2002 }
2003 }
2004
2005out:
2006 if (!ret)
2007 ret = free_io_failure(inode, failrec, did_repair);
2008
2009 return ret;
2010}
2011
2012/*
2013 * this is a generic handler for readpage errors (default
2014 * readpage_io_failed_hook). if other copies exist, read those and write back
2015 * good data to the failed position. does not investigate in remapping the
2016 * failed extent elsewhere, hoping the device will be smart enough to do this as
2017 * needed
2018 */
2019
2020static int bio_readpage_error(struct bio *failed_bio, struct page *page,
2021 u64 start, u64 end, int failed_mirror,
2022 struct extent_state *state)
2023{
2024 struct io_failure_record *failrec = NULL;
2025 u64 private;
2026 struct extent_map *em;
2027 struct inode *inode = page->mapping->host;
2028 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2029 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2030 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2031 struct bio *bio;
2032 int num_copies;
2033 int ret;
2034 int read_mode;
2035 u64 logical;
2036
2037 BUG_ON(failed_bio->bi_rw & REQ_WRITE);
2038
2039 ret = get_state_private(failure_tree, start, &private);
2040 if (ret) {
2041 failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
2042 if (!failrec)
2043 return -ENOMEM;
2044 failrec->start = start;
2045 failrec->len = end - start + 1;
2046 failrec->this_mirror = 0;
2047 failrec->bio_flags = 0;
2048 failrec->in_validation = 0;
2049
2050 read_lock(&em_tree->lock);
2051 em = lookup_extent_mapping(em_tree, start, failrec->len);
2052 if (!em) {
2053 read_unlock(&em_tree->lock);
2054 kfree(failrec);
2055 return -EIO;
2056 }
2057
2058 if (em->start > start || em->start + em->len < start) {
2059 free_extent_map(em);
2060 em = NULL;
2061 }
2062 read_unlock(&em_tree->lock);
2063
2064 if (!em || IS_ERR(em)) {
2065 kfree(failrec);
2066 return -EIO;
2067 }
2068 logical = start - em->start;
2069 logical = em->block_start + logical;
2070 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2071 logical = em->block_start;
2072 failrec->bio_flags = EXTENT_BIO_COMPRESSED;
2073 extent_set_compress_type(&failrec->bio_flags,
2074 em->compress_type);
2075 }
2076 pr_debug("bio_readpage_error: (new) logical=%llu, start=%llu, "
2077 "len=%llu\n", logical, start, failrec->len);
2078 failrec->logical = logical;
2079 free_extent_map(em);
2080
2081 /* set the bits in the private failure tree */
2082 ret = set_extent_bits(failure_tree, start, end,
2083 EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
2084 if (ret >= 0)
2085 ret = set_state_private(failure_tree, start,
2086 (u64)(unsigned long)failrec);
2087 /* set the bits in the inode's tree */
2088 if (ret >= 0)
2089 ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED,
2090 GFP_NOFS);
2091 if (ret < 0) {
2092 kfree(failrec);
2093 return ret;
2094 }
2095 } else {
2096 failrec = (struct io_failure_record *)(unsigned long)private;
2097 pr_debug("bio_readpage_error: (found) logical=%llu, "
2098 "start=%llu, len=%llu, validation=%d\n",
2099 failrec->logical, failrec->start, failrec->len,
2100 failrec->in_validation);
2101 /*
2102 * when data can be on disk more than twice, add to failrec here
2103 * (e.g. with a list for failed_mirror) to make
2104 * clean_io_failure() clean all those errors at once.
2105 */
2106 }
2107 num_copies = btrfs_num_copies(
2108 &BTRFS_I(inode)->root->fs_info->mapping_tree,
2109 failrec->logical, failrec->len);
2110 if (num_copies == 1) {
2111 /*
2112 * we only have a single copy of the data, so don't bother with
2113 * all the retry and error correction code that follows. no
2114 * matter what the error is, it is very likely to persist.
2115 */
2116 pr_debug("bio_readpage_error: cannot repair, num_copies == 1. "
2117 "state=%p, num_copies=%d, next_mirror %d, "
2118 "failed_mirror %d\n", state, num_copies,
2119 failrec->this_mirror, failed_mirror);
2120 free_io_failure(inode, failrec, 0);
2121 return -EIO;
2122 }
2123
2124 if (!state) {
2125 spin_lock(&tree->lock);
2126 state = find_first_extent_bit_state(tree, failrec->start,
2127 EXTENT_LOCKED);
2128 if (state && state->start != failrec->start)
2129 state = NULL;
2130 spin_unlock(&tree->lock);
2131 }
2132
2133 /*
2134 * there are two premises:
2135 * a) deliver good data to the caller
2136 * b) correct the bad sectors on disk
2137 */
2138 if (failed_bio->bi_vcnt > 1) {
2139 /*
2140 * to fulfill b), we need to know the exact failing sectors, as
2141 * we don't want to rewrite any more than the failed ones. thus,
2142 * we need separate read requests for the failed bio
2143 *
2144 * if the following BUG_ON triggers, our validation request got
2145 * merged. we need separate requests for our algorithm to work.
2146 */
2147 BUG_ON(failrec->in_validation);
2148 failrec->in_validation = 1;
2149 failrec->this_mirror = failed_mirror;
2150 read_mode = READ_SYNC | REQ_FAILFAST_DEV;
2151 } else {
2152 /*
2153 * we're ready to fulfill a) and b) alongside. get a good copy
2154 * of the failed sector and if we succeed, we have setup
2155 * everything for repair_io_failure to do the rest for us.
2156 */
2157 if (failrec->in_validation) {
2158 BUG_ON(failrec->this_mirror != failed_mirror);
2159 failrec->in_validation = 0;
2160 failrec->this_mirror = 0;
2161 }
2162 failrec->failed_mirror = failed_mirror;
2163 failrec->this_mirror++;
2164 if (failrec->this_mirror == failed_mirror)
2165 failrec->this_mirror++;
2166 read_mode = READ_SYNC;
2167 }
2168
2169 if (!state || failrec->this_mirror > num_copies) {
2170 pr_debug("bio_readpage_error: (fail) state=%p, num_copies=%d, "
2171 "next_mirror %d, failed_mirror %d\n", state,
2172 num_copies, failrec->this_mirror, failed_mirror);
2173 free_io_failure(inode, failrec, 0);
2174 return -EIO;
2175 }
2176
2177 bio = bio_alloc(GFP_NOFS, 1);
2178 if (!bio) {
2179 free_io_failure(inode, failrec, 0);
2180 return -EIO;
2181 }
2182 bio->bi_private = state;
2183 bio->bi_end_io = failed_bio->bi_end_io;
2184 bio->bi_sector = failrec->logical >> 9;
2185 bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
2186 bio->bi_size = 0;
2187
2188 bio_add_page(bio, page, failrec->len, start - page_offset(page));
2189
2190 pr_debug("bio_readpage_error: submitting new read[%#x] to "
2191 "this_mirror=%d, num_copies=%d, in_validation=%d\n", read_mode,
2192 failrec->this_mirror, num_copies, failrec->in_validation);
2193
2194 ret = tree->ops->submit_bio_hook(inode, read_mode, bio,
2195 failrec->this_mirror,
2196 failrec->bio_flags, 0);
2197 return ret;
2198}
2199
2200/* lots and lots of room for performance fixes in the end_bio funcs */
2201
2202int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
2203{
2204 int uptodate = (err == 0);
2205 struct extent_io_tree *tree;
2206 int ret;
2207
2208 tree = &BTRFS_I(page->mapping->host)->io_tree;
2209
2210 if (tree->ops && tree->ops->writepage_end_io_hook) {
2211 ret = tree->ops->writepage_end_io_hook(page, start,
2212 end, NULL, uptodate);
2213 if (ret)
2214 uptodate = 0;
2215 }
2216
2217 if (!uptodate) {
2218 ClearPageUptodate(page);
2219 SetPageError(page);
2220 }
2221 return 0;
2222}
2223
2224/*
2225 * after a writepage IO is done, we need to:
2226 * clear the uptodate bits on error
2227 * clear the writeback bits in the extent tree for this IO
2228 * end_page_writeback if the page has no more pending IO
2229 *
2230 * Scheduling is not allowed, so the extent state tree is expected
2231 * to have one and only one object corresponding to this IO.
2232 */
2233static void end_bio_extent_writepage(struct bio *bio, int err)
2234{
2235 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
2236 struct extent_io_tree *tree;
2237 u64 start;
2238 u64 end;
2239 int whole_page;
2240
2241 do {
2242 struct page *page = bvec->bv_page;
2243 tree = &BTRFS_I(page->mapping->host)->io_tree;
2244
2245 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
2246 bvec->bv_offset;
2247 end = start + bvec->bv_len - 1;
2248
2249 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
2250 whole_page = 1;
2251 else
2252 whole_page = 0;
2253
2254 if (--bvec >= bio->bi_io_vec)
2255 prefetchw(&bvec->bv_page->flags);
2256
2257 if (end_extent_writepage(page, err, start, end))
2258 continue;
2259
2260 if (whole_page)
2261 end_page_writeback(page);
2262 else
2263 check_page_writeback(tree, page);
2264 } while (bvec >= bio->bi_io_vec);
2265
2266 bio_put(bio);
2267}
2268
2269/*
2270 * after a readpage IO is done, we need to:
2271 * clear the uptodate bits on error
2272 * set the uptodate bits if things worked
2273 * set the page up to date if all extents in the tree are uptodate
2274 * clear the lock bit in the extent tree
2275 * unlock the page if there are no other extents locked for it
2276 *
2277 * Scheduling is not allowed, so the extent state tree is expected
2278 * to have one and only one object corresponding to this IO.
2279 */
2280static void end_bio_extent_readpage(struct bio *bio, int err)
2281{
2282 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
2283 struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
2284 struct bio_vec *bvec = bio->bi_io_vec;
2285 struct extent_io_tree *tree;
2286 u64 start;
2287 u64 end;
2288 int whole_page;
2289 int mirror;
2290 int ret;
2291
2292 if (err)
2293 uptodate = 0;
2294
2295 do {
2296 struct page *page = bvec->bv_page;
2297 struct extent_state *cached = NULL;
2298 struct extent_state *state;
2299
2300 pr_debug("end_bio_extent_readpage: bi_vcnt=%d, idx=%d, err=%d, "
2301 "mirror=%ld\n", bio->bi_vcnt, bio->bi_idx, err,
2302 (long int)bio->bi_bdev);
2303 tree = &BTRFS_I(page->mapping->host)->io_tree;
2304
2305 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
2306 bvec->bv_offset;
2307 end = start + bvec->bv_len - 1;
2308
2309 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
2310 whole_page = 1;
2311 else
2312 whole_page = 0;
2313
2314 if (++bvec <= bvec_end)
2315 prefetchw(&bvec->bv_page->flags);
2316
2317 spin_lock(&tree->lock);
2318 state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
2319 if (state && state->start == start) {
2320 /*
2321 * take a reference on the state, unlock will drop
2322 * the ref
2323 */
2324 cache_state(state, &cached);
2325 }
2326 spin_unlock(&tree->lock);
2327
2328 mirror = (int)(unsigned long)bio->bi_bdev;
2329 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
2330 ret = tree->ops->readpage_end_io_hook(page, start, end,
2331 state, mirror);
2332 if (ret)
2333 uptodate = 0;
2334 else
2335 clean_io_failure(start, page);
2336 }
2337
2338 if (!uptodate && tree->ops && tree->ops->readpage_io_failed_hook) {
2339 ret = tree->ops->readpage_io_failed_hook(page, mirror);
2340 if (!ret && !err &&
2341 test_bit(BIO_UPTODATE, &bio->bi_flags))
2342 uptodate = 1;
2343 } else if (!uptodate) {
2344 /*
2345 * The generic bio_readpage_error handles errors the
2346 * following way: If possible, new read requests are
2347 * created and submitted and will end up in
2348 * end_bio_extent_readpage as well (if we're lucky, not
2349 * in the !uptodate case). In that case it returns 0 and
2350 * we just go on with the next page in our bio. If it
2351 * can't handle the error it will return -EIO and we
2352 * remain responsible for that page.
2353 */
2354 ret = bio_readpage_error(bio, page, start, end, mirror, NULL);
2355 if (ret == 0) {
2356 uptodate =
2357 test_bit(BIO_UPTODATE, &bio->bi_flags);
2358 if (err)
2359 uptodate = 0;
2360 uncache_state(&cached);
2361 continue;
2362 }
2363 }
2364
2365 if (uptodate && tree->track_uptodate) {
2366 set_extent_uptodate(tree, start, end, &cached,
2367 GFP_ATOMIC);
2368 }
2369 unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
2370
2371 if (whole_page) {
2372 if (uptodate) {
2373 SetPageUptodate(page);
2374 } else {
2375 ClearPageUptodate(page);
2376 SetPageError(page);
2377 }
2378 unlock_page(page);
2379 } else {
2380 if (uptodate) {
2381 check_page_uptodate(tree, page);
2382 } else {
2383 ClearPageUptodate(page);
2384 SetPageError(page);
2385 }
2386 check_page_locked(tree, page);
2387 }
2388 } while (bvec <= bvec_end);
2389
2390 bio_put(bio);
2391}
2392
2393struct bio *
2394btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
2395 gfp_t gfp_flags)
2396{
2397 struct bio *bio;
2398
2399 bio = bio_alloc(gfp_flags, nr_vecs);
2400
2401 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2402 while (!bio && (nr_vecs /= 2))
2403 bio = bio_alloc(gfp_flags, nr_vecs);
2404 }
2405
2406 if (bio) {
2407 bio->bi_size = 0;
2408 bio->bi_bdev = bdev;
2409 bio->bi_sector = first_sector;
2410 }
2411 return bio;
2412}
2413
2414/*
2415 * Since writes are async, they will only return -ENOMEM.
2416 * Reads can return the full range of I/O error conditions.
2417 */
2418static int __must_check submit_one_bio(int rw, struct bio *bio,
2419 int mirror_num, unsigned long bio_flags)
2420{
2421 int ret = 0;
2422 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
2423 struct page *page = bvec->bv_page;
2424 struct extent_io_tree *tree = bio->bi_private;
2425 u64 start;
2426
2427 start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
2428
2429 bio->bi_private = NULL;
2430
2431 bio_get(bio);
2432
2433 if (tree->ops && tree->ops->submit_bio_hook)
2434 ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
2435 mirror_num, bio_flags, start);
2436 else
2437 btrfsic_submit_bio(rw, bio);
2438
2439 if (bio_flagged(bio, BIO_EOPNOTSUPP))
2440 ret = -EOPNOTSUPP;
2441 bio_put(bio);
2442 return ret;
2443}
2444
2445static int merge_bio(struct extent_io_tree *tree, struct page *page,
2446 unsigned long offset, size_t size, struct bio *bio,
2447 unsigned long bio_flags)
2448{
2449 int ret = 0;
2450 if (tree->ops && tree->ops->merge_bio_hook)
2451 ret = tree->ops->merge_bio_hook(page, offset, size, bio,
2452 bio_flags);
2453 BUG_ON(ret < 0);
2454 return ret;
2455
2456}
2457
2458static int submit_extent_page(int rw, struct extent_io_tree *tree,
2459 struct page *page, sector_t sector,
2460 size_t size, unsigned long offset,
2461 struct block_device *bdev,
2462 struct bio **bio_ret,
2463 unsigned long max_pages,
2464 bio_end_io_t end_io_func,
2465 int mirror_num,
2466 unsigned long prev_bio_flags,
2467 unsigned long bio_flags)
2468{
2469 int ret = 0;
2470 struct bio *bio;
2471 int nr;
2472 int contig = 0;
2473 int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
2474 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2475 size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
2476
2477 if (bio_ret && *bio_ret) {
2478 bio = *bio_ret;
2479 if (old_compressed)
2480 contig = bio->bi_sector == sector;
2481 else
2482 contig = bio->bi_sector + (bio->bi_size >> 9) ==
2483 sector;
2484
2485 if (prev_bio_flags != bio_flags || !contig ||
2486 merge_bio(tree, page, offset, page_size, bio, bio_flags) ||
2487 bio_add_page(bio, page, page_size, offset) < page_size) {
2488 ret = submit_one_bio(rw, bio, mirror_num,
2489 prev_bio_flags);
2490 if (ret < 0)
2491 return ret;
2492 bio = NULL;
2493 } else {
2494 return 0;
2495 }
2496 }
2497 if (this_compressed)
2498 nr = BIO_MAX_PAGES;
2499 else
2500 nr = bio_get_nr_vecs(bdev);
2501
2502 bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
2503 if (!bio)
2504 return -ENOMEM;
2505
2506 bio_add_page(bio, page, page_size, offset);
2507 bio->bi_end_io = end_io_func;
2508 bio->bi_private = tree;
2509
2510 if (bio_ret)
2511 *bio_ret = bio;
2512 else
2513 ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
2514
2515 return ret;
2516}
2517
2518void attach_extent_buffer_page(struct extent_buffer *eb, struct page *page)
2519{
2520 if (!PagePrivate(page)) {
2521 SetPagePrivate(page);
2522 page_cache_get(page);
2523 set_page_private(page, (unsigned long)eb);
2524 } else {
2525 WARN_ON(page->private != (unsigned long)eb);
2526 }
2527}
2528
2529void set_page_extent_mapped(struct page *page)
2530{
2531 if (!PagePrivate(page)) {
2532 SetPagePrivate(page);
2533 page_cache_get(page);
2534 set_page_private(page, EXTENT_PAGE_PRIVATE);
2535 }
2536}
2537
2538/*
2539 * basic readpage implementation. Locked extent state structs are inserted
2540 * into the tree that are removed when the IO is done (by the end_io
2541 * handlers)
2542 * XXX JDM: This needs looking at to ensure proper page locking
2543 */
2544static int __extent_read_full_page(struct extent_io_tree *tree,
2545 struct page *page,
2546 get_extent_t *get_extent,
2547 struct bio **bio, int mirror_num,
2548 unsigned long *bio_flags)
2549{
2550 struct inode *inode = page->mapping->host;
2551 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2552 u64 page_end = start + PAGE_CACHE_SIZE - 1;
2553 u64 end;
2554 u64 cur = start;
2555 u64 extent_offset;
2556 u64 last_byte = i_size_read(inode);
2557 u64 block_start;
2558 u64 cur_end;
2559 sector_t sector;
2560 struct extent_map *em;
2561 struct block_device *bdev;
2562 struct btrfs_ordered_extent *ordered;
2563 int ret;
2564 int nr = 0;
2565 size_t pg_offset = 0;
2566 size_t iosize;
2567 size_t disk_io_size;
2568 size_t blocksize = inode->i_sb->s_blocksize;
2569 unsigned long this_bio_flag = 0;
2570
2571 set_page_extent_mapped(page);
2572
2573 if (!PageUptodate(page)) {
2574 if (cleancache_get_page(page) == 0) {
2575 BUG_ON(blocksize != PAGE_SIZE);
2576 goto out;
2577 }
2578 }
2579
2580 end = page_end;
2581 while (1) {
2582 lock_extent(tree, start, end);
2583 ordered = btrfs_lookup_ordered_extent(inode, start);
2584 if (!ordered)
2585 break;
2586 unlock_extent(tree, start, end);
2587 btrfs_start_ordered_extent(inode, ordered, 1);
2588 btrfs_put_ordered_extent(ordered);
2589 }
2590
2591 if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
2592 char *userpage;
2593 size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
2594
2595 if (zero_offset) {
2596 iosize = PAGE_CACHE_SIZE - zero_offset;
2597 userpage = kmap_atomic(page);
2598 memset(userpage + zero_offset, 0, iosize);
2599 flush_dcache_page(page);
2600 kunmap_atomic(userpage);
2601 }
2602 }
2603 while (cur <= end) {
2604 if (cur >= last_byte) {
2605 char *userpage;
2606 struct extent_state *cached = NULL;
2607
2608 iosize = PAGE_CACHE_SIZE - pg_offset;
2609 userpage = kmap_atomic(page);
2610 memset(userpage + pg_offset, 0, iosize);
2611 flush_dcache_page(page);
2612 kunmap_atomic(userpage);
2613 set_extent_uptodate(tree, cur, cur + iosize - 1,
2614 &cached, GFP_NOFS);
2615 unlock_extent_cached(tree, cur, cur + iosize - 1,
2616 &cached, GFP_NOFS);
2617 break;
2618 }
2619 em = get_extent(inode, page, pg_offset, cur,
2620 end - cur + 1, 0);
2621 if (IS_ERR_OR_NULL(em)) {
2622 SetPageError(page);
2623 unlock_extent(tree, cur, end);
2624 break;
2625 }
2626 extent_offset = cur - em->start;
2627 BUG_ON(extent_map_end(em) <= cur);
2628 BUG_ON(end < cur);
2629
2630 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2631 this_bio_flag = EXTENT_BIO_COMPRESSED;
2632 extent_set_compress_type(&this_bio_flag,
2633 em->compress_type);
2634 }
2635
2636 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2637 cur_end = min(extent_map_end(em) - 1, end);
2638 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2639 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
2640 disk_io_size = em->block_len;
2641 sector = em->block_start >> 9;
2642 } else {
2643 sector = (em->block_start + extent_offset) >> 9;
2644 disk_io_size = iosize;
2645 }
2646 bdev = em->bdev;
2647 block_start = em->block_start;
2648 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2649 block_start = EXTENT_MAP_HOLE;
2650 free_extent_map(em);
2651 em = NULL;
2652
2653 /* we've found a hole, just zero and go on */
2654 if (block_start == EXTENT_MAP_HOLE) {
2655 char *userpage;
2656 struct extent_state *cached = NULL;
2657
2658 userpage = kmap_atomic(page);
2659 memset(userpage + pg_offset, 0, iosize);
2660 flush_dcache_page(page);
2661 kunmap_atomic(userpage);
2662
2663 set_extent_uptodate(tree, cur, cur + iosize - 1,
2664 &cached, GFP_NOFS);
2665 unlock_extent_cached(tree, cur, cur + iosize - 1,
2666 &cached, GFP_NOFS);
2667 cur = cur + iosize;
2668 pg_offset += iosize;
2669 continue;
2670 }
2671 /* the get_extent function already copied into the page */
2672 if (test_range_bit(tree, cur, cur_end,
2673 EXTENT_UPTODATE, 1, NULL)) {
2674 check_page_uptodate(tree, page);
2675 unlock_extent(tree, cur, cur + iosize - 1);
2676 cur = cur + iosize;
2677 pg_offset += iosize;
2678 continue;
2679 }
2680 /* we have an inline extent but it didn't get marked up
2681 * to date. Error out
2682 */
2683 if (block_start == EXTENT_MAP_INLINE) {
2684 SetPageError(page);
2685 unlock_extent(tree, cur, cur + iosize - 1);
2686 cur = cur + iosize;
2687 pg_offset += iosize;
2688 continue;
2689 }
2690
2691 ret = 0;
2692 if (tree->ops && tree->ops->readpage_io_hook) {
2693 ret = tree->ops->readpage_io_hook(page, cur,
2694 cur + iosize - 1);
2695 }
2696 if (!ret) {
2697 unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
2698 pnr -= page->index;
2699 ret = submit_extent_page(READ, tree, page,
2700 sector, disk_io_size, pg_offset,
2701 bdev, bio, pnr,
2702 end_bio_extent_readpage, mirror_num,
2703 *bio_flags,
2704 this_bio_flag);
2705 BUG_ON(ret == -ENOMEM);
2706 nr++;
2707 *bio_flags = this_bio_flag;
2708 }
2709 if (ret)
2710 SetPageError(page);
2711 cur = cur + iosize;
2712 pg_offset += iosize;
2713 }
2714out:
2715 if (!nr) {
2716 if (!PageError(page))
2717 SetPageUptodate(page);
2718 unlock_page(page);
2719 }
2720 return 0;
2721}
2722
2723int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
2724 get_extent_t *get_extent, int mirror_num)
2725{
2726 struct bio *bio = NULL;
2727 unsigned long bio_flags = 0;
2728 int ret;
2729
2730 ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
2731 &bio_flags);
2732 if (bio)
2733 ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
2734 return ret;
2735}
2736
2737static noinline void update_nr_written(struct page *page,
2738 struct writeback_control *wbc,
2739 unsigned long nr_written)
2740{
2741 wbc->nr_to_write -= nr_written;
2742 if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
2743 wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
2744 page->mapping->writeback_index = page->index + nr_written;
2745}
2746
2747/*
2748 * the writepage semantics are similar to regular writepage. extent
2749 * records are inserted to lock ranges in the tree, and as dirty areas
2750 * are found, they are marked writeback. Then the lock bits are removed
2751 * and the end_io handler clears the writeback ranges
2752 */
2753static int __extent_writepage(struct page *page, struct writeback_control *wbc,
2754 void *data)
2755{
2756 struct inode *inode = page->mapping->host;
2757 struct extent_page_data *epd = data;
2758 struct extent_io_tree *tree = epd->tree;
2759 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2760 u64 delalloc_start;
2761 u64 page_end = start + PAGE_CACHE_SIZE - 1;
2762 u64 end;
2763 u64 cur = start;
2764 u64 extent_offset;
2765 u64 last_byte = i_size_read(inode);
2766 u64 block_start;
2767 u64 iosize;
2768 sector_t sector;
2769 struct extent_state *cached_state = NULL;
2770 struct extent_map *em;
2771 struct block_device *bdev;
2772 int ret;
2773 int nr = 0;
2774 size_t pg_offset = 0;
2775 size_t blocksize;
2776 loff_t i_size = i_size_read(inode);
2777 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2778 u64 nr_delalloc;
2779 u64 delalloc_end;
2780 int page_started;
2781 int compressed;
2782 int write_flags;
2783 unsigned long nr_written = 0;
2784 bool fill_delalloc = true;
2785
2786 if (wbc->sync_mode == WB_SYNC_ALL)
2787 write_flags = WRITE_SYNC;
2788 else
2789 write_flags = WRITE;
2790
2791 trace___extent_writepage(page, inode, wbc);
2792
2793 WARN_ON(!PageLocked(page));
2794
2795 ClearPageError(page);
2796
2797 pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2798 if (page->index > end_index ||
2799 (page->index == end_index && !pg_offset)) {
2800 page->mapping->a_ops->invalidatepage(page, 0);
2801 unlock_page(page);
2802 return 0;
2803 }
2804
2805 if (page->index == end_index) {
2806 char *userpage;
2807
2808 userpage = kmap_atomic(page);
2809 memset(userpage + pg_offset, 0,
2810 PAGE_CACHE_SIZE - pg_offset);
2811 kunmap_atomic(userpage);
2812 flush_dcache_page(page);
2813 }
2814 pg_offset = 0;
2815
2816 set_page_extent_mapped(page);
2817
2818 if (!tree->ops || !tree->ops->fill_delalloc)
2819 fill_delalloc = false;
2820
2821 delalloc_start = start;
2822 delalloc_end = 0;
2823 page_started = 0;
2824 if (!epd->extent_locked && fill_delalloc) {
2825 u64 delalloc_to_write = 0;
2826 /*
2827 * make sure the wbc mapping index is at least updated
2828 * to this page.
2829 */
2830 update_nr_written(page, wbc, 0);
2831
2832 while (delalloc_end < page_end) {
2833 nr_delalloc = find_lock_delalloc_range(inode, tree,
2834 page,
2835 &delalloc_start,
2836 &delalloc_end,
2837 128 * 1024 * 1024);
2838 if (nr_delalloc == 0) {
2839 delalloc_start = delalloc_end + 1;
2840 continue;
2841 }
2842 ret = tree->ops->fill_delalloc(inode, page,
2843 delalloc_start,
2844 delalloc_end,
2845 &page_started,
2846 &nr_written);
2847 /* File system has been set read-only */
2848 if (ret) {
2849 SetPageError(page);
2850 goto done;
2851 }
2852 /*
2853 * delalloc_end is already one less than the total
2854 * length, so we don't subtract one from
2855 * PAGE_CACHE_SIZE
2856 */
2857 delalloc_to_write += (delalloc_end - delalloc_start +
2858 PAGE_CACHE_SIZE) >>
2859 PAGE_CACHE_SHIFT;
2860 delalloc_start = delalloc_end + 1;
2861 }
2862 if (wbc->nr_to_write < delalloc_to_write) {
2863 int thresh = 8192;
2864
2865 if (delalloc_to_write < thresh * 2)
2866 thresh = delalloc_to_write;
2867 wbc->nr_to_write = min_t(u64, delalloc_to_write,
2868 thresh);
2869 }
2870
2871 /* did the fill delalloc function already unlock and start
2872 * the IO?
2873 */
2874 if (page_started) {
2875 ret = 0;
2876 /*
2877 * we've unlocked the page, so we can't update
2878 * the mapping's writeback index, just update
2879 * nr_to_write.
2880 */
2881 wbc->nr_to_write -= nr_written;
2882 goto done_unlocked;
2883 }
2884 }
2885 if (tree->ops && tree->ops->writepage_start_hook) {
2886 ret = tree->ops->writepage_start_hook(page, start,
2887 page_end);
2888 if (ret) {
2889 /* Fixup worker will requeue */
2890 if (ret == -EBUSY)
2891 wbc->pages_skipped++;
2892 else
2893 redirty_page_for_writepage(wbc, page);
2894 update_nr_written(page, wbc, nr_written);
2895 unlock_page(page);
2896 ret = 0;
2897 goto done_unlocked;
2898 }
2899 }
2900
2901 /*
2902 * we don't want to touch the inode after unlocking the page,
2903 * so we update the mapping writeback index now
2904 */
2905 update_nr_written(page, wbc, nr_written + 1);
2906
2907 end = page_end;
2908 if (last_byte <= start) {
2909 if (tree->ops && tree->ops->writepage_end_io_hook)
2910 tree->ops->writepage_end_io_hook(page, start,
2911 page_end, NULL, 1);
2912 goto done;
2913 }
2914
2915 blocksize = inode->i_sb->s_blocksize;
2916
2917 while (cur <= end) {
2918 if (cur >= last_byte) {
2919 if (tree->ops && tree->ops->writepage_end_io_hook)
2920 tree->ops->writepage_end_io_hook(page, cur,
2921 page_end, NULL, 1);
2922 break;
2923 }
2924 em = epd->get_extent(inode, page, pg_offset, cur,
2925 end - cur + 1, 1);
2926 if (IS_ERR_OR_NULL(em)) {
2927 SetPageError(page);
2928 break;
2929 }
2930
2931 extent_offset = cur - em->start;
2932 BUG_ON(extent_map_end(em) <= cur);
2933 BUG_ON(end < cur);
2934 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2935 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2936 sector = (em->block_start + extent_offset) >> 9;
2937 bdev = em->bdev;
2938 block_start = em->block_start;
2939 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2940 free_extent_map(em);
2941 em = NULL;
2942
2943 /*
2944 * compressed and inline extents are written through other
2945 * paths in the FS
2946 */
2947 if (compressed || block_start == EXTENT_MAP_HOLE ||
2948 block_start == EXTENT_MAP_INLINE) {
2949 /*
2950 * end_io notification does not happen here for
2951 * compressed extents
2952 */
2953 if (!compressed && tree->ops &&
2954 tree->ops->writepage_end_io_hook)
2955 tree->ops->writepage_end_io_hook(page, cur,
2956 cur + iosize - 1,
2957 NULL, 1);
2958 else if (compressed) {
2959 /* we don't want to end_page_writeback on
2960 * a compressed extent. this happens
2961 * elsewhere
2962 */
2963 nr++;
2964 }
2965
2966 cur += iosize;
2967 pg_offset += iosize;
2968 continue;
2969 }
2970 /* leave this out until we have a page_mkwrite call */
2971 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2972 EXTENT_DIRTY, 0, NULL)) {
2973 cur = cur + iosize;
2974 pg_offset += iosize;
2975 continue;
2976 }
2977
2978 if (tree->ops && tree->ops->writepage_io_hook) {
2979 ret = tree->ops->writepage_io_hook(page, cur,
2980 cur + iosize - 1);
2981 } else {
2982 ret = 0;
2983 }
2984 if (ret) {
2985 SetPageError(page);
2986 } else {
2987 unsigned long max_nr = end_index + 1;
2988
2989 set_range_writeback(tree, cur, cur + iosize - 1);
2990 if (!PageWriteback(page)) {
2991 printk(KERN_ERR "btrfs warning page %lu not "
2992 "writeback, cur %llu end %llu\n",
2993 page->index, (unsigned long long)cur,
2994 (unsigned long long)end);
2995 }
2996
2997 ret = submit_extent_page(write_flags, tree, page,
2998 sector, iosize, pg_offset,
2999 bdev, &epd->bio, max_nr,
3000 end_bio_extent_writepage,
3001 0, 0, 0);
3002 if (ret)
3003 SetPageError(page);
3004 }
3005 cur = cur + iosize;
3006 pg_offset += iosize;
3007 nr++;
3008 }
3009done:
3010 if (nr == 0) {
3011 /* make sure the mapping tag for page dirty gets cleared */
3012 set_page_writeback(page);
3013 end_page_writeback(page);
3014 }
3015 unlock_page(page);
3016
3017done_unlocked:
3018
3019 /* drop our reference on any cached states */
3020 free_extent_state(cached_state);
3021 return 0;
3022}
3023
3024static int eb_wait(void *word)
3025{
3026 io_schedule();
3027 return 0;
3028}
3029
3030static void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3031{
3032 wait_on_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK, eb_wait,
3033 TASK_UNINTERRUPTIBLE);
3034}
3035
3036static int lock_extent_buffer_for_io(struct extent_buffer *eb,
3037 struct btrfs_fs_info *fs_info,
3038 struct extent_page_data *epd)
3039{
3040 unsigned long i, num_pages;
3041 int flush = 0;
3042 int ret = 0;
3043
3044 if (!btrfs_try_tree_write_lock(eb)) {
3045 flush = 1;
3046 flush_write_bio(epd);
3047 btrfs_tree_lock(eb);
3048 }
3049
3050 if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
3051 btrfs_tree_unlock(eb);
3052 if (!epd->sync_io)
3053 return 0;
3054 if (!flush) {
3055 flush_write_bio(epd);
3056 flush = 1;
3057 }
3058 while (1) {
3059 wait_on_extent_buffer_writeback(eb);
3060 btrfs_tree_lock(eb);
3061 if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
3062 break;
3063 btrfs_tree_unlock(eb);
3064 }
3065 }
3066
3067 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3068 set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3069 btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3070 spin_lock(&fs_info->delalloc_lock);
3071 if (fs_info->dirty_metadata_bytes >= eb->len)
3072 fs_info->dirty_metadata_bytes -= eb->len;
3073 else
3074 WARN_ON(1);
3075 spin_unlock(&fs_info->delalloc_lock);
3076 ret = 1;
3077 }
3078
3079 btrfs_tree_unlock(eb);
3080
3081 if (!ret)
3082 return ret;
3083
3084 num_pages = num_extent_pages(eb->start, eb->len);
3085 for (i = 0; i < num_pages; i++) {
3086 struct page *p = extent_buffer_page(eb, i);
3087
3088 if (!trylock_page(p)) {
3089 if (!flush) {
3090 flush_write_bio(epd);
3091 flush = 1;
3092 }
3093 lock_page(p);
3094 }
3095 }
3096
3097 return ret;
3098}
3099
3100static void end_extent_buffer_writeback(struct extent_buffer *eb)
3101{
3102 clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3103 smp_mb__after_clear_bit();
3104 wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
3105}
3106
3107static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
3108{
3109 int uptodate = err == 0;
3110 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
3111 struct extent_buffer *eb;
3112 int done;
3113
3114 do {
3115 struct page *page = bvec->bv_page;
3116
3117 bvec--;
3118 eb = (struct extent_buffer *)page->private;
3119 BUG_ON(!eb);
3120 done = atomic_dec_and_test(&eb->io_pages);
3121
3122 if (!uptodate || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
3123 set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
3124 ClearPageUptodate(page);
3125 SetPageError(page);
3126 }
3127
3128 end_page_writeback(page);
3129
3130 if (!done)
3131 continue;
3132
3133 end_extent_buffer_writeback(eb);
3134 } while (bvec >= bio->bi_io_vec);
3135
3136 bio_put(bio);
3137
3138}
3139
3140static int write_one_eb(struct extent_buffer *eb,
3141 struct btrfs_fs_info *fs_info,
3142 struct writeback_control *wbc,
3143 struct extent_page_data *epd)
3144{
3145 struct block_device *bdev = fs_info->fs_devices->latest_bdev;
3146 u64 offset = eb->start;
3147 unsigned long i, num_pages;
3148 int rw = (epd->sync_io ? WRITE_SYNC : WRITE);
3149 int ret = 0;
3150
3151 clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
3152 num_pages = num_extent_pages(eb->start, eb->len);
3153 atomic_set(&eb->io_pages, num_pages);
3154 for (i = 0; i < num_pages; i++) {
3155 struct page *p = extent_buffer_page(eb, i);
3156
3157 clear_page_dirty_for_io(p);
3158 set_page_writeback(p);
3159 ret = submit_extent_page(rw, eb->tree, p, offset >> 9,
3160 PAGE_CACHE_SIZE, 0, bdev, &epd->bio,
3161 -1, end_bio_extent_buffer_writepage,
3162 0, 0, 0);
3163 if (ret) {
3164 set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
3165 SetPageError(p);
3166 if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
3167 end_extent_buffer_writeback(eb);
3168 ret = -EIO;
3169 break;
3170 }
3171 offset += PAGE_CACHE_SIZE;
3172 update_nr_written(p, wbc, 1);
3173 unlock_page(p);
3174 }
3175
3176 if (unlikely(ret)) {
3177 for (; i < num_pages; i++) {
3178 struct page *p = extent_buffer_page(eb, i);
3179 unlock_page(p);
3180 }
3181 }
3182
3183 return ret;
3184}
3185
3186int btree_write_cache_pages(struct address_space *mapping,
3187 struct writeback_control *wbc)
3188{
3189 struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
3190 struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
3191 struct extent_buffer *eb, *prev_eb = NULL;
3192 struct extent_page_data epd = {
3193 .bio = NULL,
3194 .tree = tree,
3195 .extent_locked = 0,
3196 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
3197 };
3198 int ret = 0;
3199 int done = 0;
3200 int nr_to_write_done = 0;
3201 struct pagevec pvec;
3202 int nr_pages;
3203 pgoff_t index;
3204 pgoff_t end; /* Inclusive */
3205 int scanned = 0;
3206 int tag;
3207
3208 pagevec_init(&pvec, 0);
3209 if (wbc->range_cyclic) {
3210 index = mapping->writeback_index; /* Start from prev offset */
3211 end = -1;
3212 } else {
3213 index = wbc->range_start >> PAGE_CACHE_SHIFT;
3214 end = wbc->range_end >> PAGE_CACHE_SHIFT;
3215 scanned = 1;
3216 }
3217 if (wbc->sync_mode == WB_SYNC_ALL)
3218 tag = PAGECACHE_TAG_TOWRITE;
3219 else
3220 tag = PAGECACHE_TAG_DIRTY;
3221retry:
3222 if (wbc->sync_mode == WB_SYNC_ALL)
3223 tag_pages_for_writeback(mapping, index, end);
3224 while (!done && !nr_to_write_done && (index <= end) &&
3225 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3226 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3227 unsigned i;
3228
3229 scanned = 1;
3230 for (i = 0; i < nr_pages; i++) {
3231 struct page *page = pvec.pages[i];
3232
3233 if (!PagePrivate(page))
3234 continue;
3235
3236 if (!wbc->range_cyclic && page->index > end) {
3237 done = 1;
3238 break;
3239 }
3240
3241 eb = (struct extent_buffer *)page->private;
3242 if (!eb) {
3243 WARN_ON(1);
3244 continue;
3245 }
3246
3247 if (eb == prev_eb)
3248 continue;
3249
3250 if (!atomic_inc_not_zero(&eb->refs)) {
3251 WARN_ON(1);
3252 continue;
3253 }
3254
3255 prev_eb = eb;
3256 ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
3257 if (!ret) {
3258 free_extent_buffer(eb);
3259 continue;
3260 }
3261
3262 ret = write_one_eb(eb, fs_info, wbc, &epd);
3263 if (ret) {
3264 done = 1;
3265 free_extent_buffer(eb);
3266 break;
3267 }
3268 free_extent_buffer(eb);
3269
3270 /*
3271 * the filesystem may choose to bump up nr_to_write.
3272 * We have to make sure to honor the new nr_to_write
3273 * at any time
3274 */
3275 nr_to_write_done = wbc->nr_to_write <= 0;
3276 }
3277 pagevec_release(&pvec);
3278 cond_resched();
3279 }
3280 if (!scanned && !done) {
3281 /*
3282 * We hit the last page and there is more work to be done: wrap
3283 * back to the start of the file
3284 */
3285 scanned = 1;
3286 index = 0;
3287 goto retry;
3288 }
3289 flush_write_bio(&epd);
3290 return ret;
3291}
3292
3293/**
3294 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3295 * @mapping: address space structure to write
3296 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
3297 * @writepage: function called for each page
3298 * @data: data passed to writepage function
3299 *
3300 * If a page is already under I/O, write_cache_pages() skips it, even
3301 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
3302 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
3303 * and msync() need to guarantee that all the data which was dirty at the time
3304 * the call was made get new I/O started against them. If wbc->sync_mode is
3305 * WB_SYNC_ALL then we were called for data integrity and we must wait for
3306 * existing IO to complete.
3307 */
3308static int extent_write_cache_pages(struct extent_io_tree *tree,
3309 struct address_space *mapping,
3310 struct writeback_control *wbc,
3311 writepage_t writepage, void *data,
3312 void (*flush_fn)(void *))
3313{
3314 struct inode *inode = mapping->host;
3315 int ret = 0;
3316 int done = 0;
3317 int nr_to_write_done = 0;
3318 struct pagevec pvec;
3319 int nr_pages;
3320 pgoff_t index;
3321 pgoff_t end; /* Inclusive */
3322 int scanned = 0;
3323 int tag;
3324
3325 /*
3326 * We have to hold onto the inode so that ordered extents can do their
3327 * work when the IO finishes. The alternative to this is failing to add
3328 * an ordered extent if the igrab() fails there and that is a huge pain
3329 * to deal with, so instead just hold onto the inode throughout the
3330 * writepages operation. If it fails here we are freeing up the inode
3331 * anyway and we'd rather not waste our time writing out stuff that is
3332 * going to be truncated anyway.
3333 */
3334 if (!igrab(inode))
3335 return 0;
3336
3337 pagevec_init(&pvec, 0);
3338 if (wbc->range_cyclic) {
3339 index = mapping->writeback_index; /* Start from prev offset */
3340 end = -1;
3341 } else {
3342 index = wbc->range_start >> PAGE_CACHE_SHIFT;
3343 end = wbc->range_end >> PAGE_CACHE_SHIFT;
3344 scanned = 1;
3345 }
3346 if (wbc->sync_mode == WB_SYNC_ALL)
3347 tag = PAGECACHE_TAG_TOWRITE;
3348 else
3349 tag = PAGECACHE_TAG_DIRTY;
3350retry:
3351 if (wbc->sync_mode == WB_SYNC_ALL)
3352 tag_pages_for_writeback(mapping, index, end);
3353 while (!done && !nr_to_write_done && (index <= end) &&
3354 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3355 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3356 unsigned i;
3357
3358 scanned = 1;
3359 for (i = 0; i < nr_pages; i++) {
3360 struct page *page = pvec.pages[i];
3361
3362 /*
3363 * At this point we hold neither mapping->tree_lock nor
3364 * lock on the page itself: the page may be truncated or
3365 * invalidated (changing page->mapping to NULL), or even
3366 * swizzled back from swapper_space to tmpfs file
3367 * mapping
3368 */
3369 if (tree->ops &&
3370 tree->ops->write_cache_pages_lock_hook) {
3371 tree->ops->write_cache_pages_lock_hook(page,
3372 data, flush_fn);
3373 } else {
3374 if (!trylock_page(page)) {
3375 flush_fn(data);
3376 lock_page(page);
3377 }
3378 }
3379
3380 if (unlikely(page->mapping != mapping)) {
3381 unlock_page(page);
3382 continue;
3383 }
3384
3385 if (!wbc->range_cyclic && page->index > end) {
3386 done = 1;
3387 unlock_page(page);
3388 continue;
3389 }
3390
3391 if (wbc->sync_mode != WB_SYNC_NONE) {
3392 if (PageWriteback(page))
3393 flush_fn(data);
3394 wait_on_page_writeback(page);
3395 }
3396
3397 if (PageWriteback(page) ||
3398 !clear_page_dirty_for_io(page)) {
3399 unlock_page(page);
3400 continue;
3401 }
3402
3403 ret = (*writepage)(page, wbc, data);
3404
3405 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
3406 unlock_page(page);
3407 ret = 0;
3408 }
3409 if (ret)
3410 done = 1;
3411
3412 /*
3413 * the filesystem may choose to bump up nr_to_write.
3414 * We have to make sure to honor the new nr_to_write
3415 * at any time
3416 */
3417 nr_to_write_done = wbc->nr_to_write <= 0;
3418 }
3419 pagevec_release(&pvec);
3420 cond_resched();
3421 }
3422 if (!scanned && !done) {
3423 /*
3424 * We hit the last page and there is more work to be done: wrap
3425 * back to the start of the file
3426 */
3427 scanned = 1;
3428 index = 0;
3429 goto retry;
3430 }
3431 btrfs_add_delayed_iput(inode);
3432 return ret;
3433}
3434
3435static void flush_epd_write_bio(struct extent_page_data *epd)
3436{
3437 if (epd->bio) {
3438 int rw = WRITE;
3439 int ret;
3440
3441 if (epd->sync_io)
3442 rw = WRITE_SYNC;
3443
3444 ret = submit_one_bio(rw, epd->bio, 0, 0);
3445 BUG_ON(ret < 0); /* -ENOMEM */
3446 epd->bio = NULL;
3447 }
3448}
3449
3450static noinline void flush_write_bio(void *data)
3451{
3452 struct extent_page_data *epd = data;
3453 flush_epd_write_bio(epd);
3454}
3455
3456int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
3457 get_extent_t *get_extent,
3458 struct writeback_control *wbc)
3459{
3460 int ret;
3461 struct extent_page_data epd = {
3462 .bio = NULL,
3463 .tree = tree,
3464 .get_extent = get_extent,
3465 .extent_locked = 0,
3466 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
3467 };
3468
3469 ret = __extent_writepage(page, wbc, &epd);
3470
3471 flush_epd_write_bio(&epd);
3472 return ret;
3473}
3474
3475int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
3476 u64 start, u64 end, get_extent_t *get_extent,
3477 int mode)
3478{
3479 int ret = 0;
3480 struct address_space *mapping = inode->i_mapping;
3481 struct page *page;
3482 unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
3483 PAGE_CACHE_SHIFT;
3484
3485 struct extent_page_data epd = {
3486 .bio = NULL,
3487 .tree = tree,
3488 .get_extent = get_extent,
3489 .extent_locked = 1,
3490 .sync_io = mode == WB_SYNC_ALL,
3491 };
3492 struct writeback_control wbc_writepages = {
3493 .sync_mode = mode,
3494 .nr_to_write = nr_pages * 2,
3495 .range_start = start,
3496 .range_end = end + 1,
3497 };
3498
3499 while (start <= end) {
3500 page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
3501 if (clear_page_dirty_for_io(page))
3502 ret = __extent_writepage(page, &wbc_writepages, &epd);
3503 else {
3504 if (tree->ops && tree->ops->writepage_end_io_hook)
3505 tree->ops->writepage_end_io_hook(page, start,
3506 start + PAGE_CACHE_SIZE - 1,
3507 NULL, 1);
3508 unlock_page(page);
3509 }
3510 page_cache_release(page);
3511 start += PAGE_CACHE_SIZE;
3512 }
3513
3514 flush_epd_write_bio(&epd);
3515 return ret;
3516}
3517
3518int extent_writepages(struct extent_io_tree *tree,
3519 struct address_space *mapping,
3520 get_extent_t *get_extent,
3521 struct writeback_control *wbc)
3522{
3523 int ret = 0;
3524 struct extent_page_data epd = {
3525 .bio = NULL,
3526 .tree = tree,
3527 .get_extent = get_extent,
3528 .extent_locked = 0,
3529 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
3530 };
3531
3532 ret = extent_write_cache_pages(tree, mapping, wbc,
3533 __extent_writepage, &epd,
3534 flush_write_bio);
3535 flush_epd_write_bio(&epd);
3536 return ret;
3537}
3538
3539int extent_readpages(struct extent_io_tree *tree,
3540 struct address_space *mapping,
3541 struct list_head *pages, unsigned nr_pages,
3542 get_extent_t get_extent)
3543{
3544 struct bio *bio = NULL;
3545 unsigned page_idx;
3546 unsigned long bio_flags = 0;
3547
3548 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
3549 struct page *page = list_entry(pages->prev, struct page, lru);
3550
3551 prefetchw(&page->flags);
3552 list_del(&page->lru);
3553 if (!add_to_page_cache_lru(page, mapping,
3554 page->index, GFP_NOFS)) {
3555 __extent_read_full_page(tree, page, get_extent,
3556 &bio, 0, &bio_flags);
3557 }
3558 page_cache_release(page);
3559 }
3560 BUG_ON(!list_empty(pages));
3561 if (bio)
3562 return submit_one_bio(READ, bio, 0, bio_flags);
3563 return 0;
3564}
3565
3566/*
3567 * basic invalidatepage code, this waits on any locked or writeback
3568 * ranges corresponding to the page, and then deletes any extent state
3569 * records from the tree
3570 */
3571int extent_invalidatepage(struct extent_io_tree *tree,
3572 struct page *page, unsigned long offset)
3573{
3574 struct extent_state *cached_state = NULL;
3575 u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
3576 u64 end = start + PAGE_CACHE_SIZE - 1;
3577 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
3578
3579 start += (offset + blocksize - 1) & ~(blocksize - 1);
3580 if (start > end)
3581 return 0;
3582
3583 lock_extent_bits(tree, start, end, 0, &cached_state);
3584 wait_on_page_writeback(page);
3585 clear_extent_bit(tree, start, end,
3586 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
3587 EXTENT_DO_ACCOUNTING,
3588 1, 1, &cached_state, GFP_NOFS);
3589 return 0;
3590}
3591
3592/*
3593 * a helper for releasepage, this tests for areas of the page that
3594 * are locked or under IO and drops the related state bits if it is safe
3595 * to drop the page.
3596 */
3597int try_release_extent_state(struct extent_map_tree *map,
3598 struct extent_io_tree *tree, struct page *page,
3599 gfp_t mask)
3600{
3601 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
3602 u64 end = start + PAGE_CACHE_SIZE - 1;
3603 int ret = 1;
3604
3605 if (test_range_bit(tree, start, end,
3606 EXTENT_IOBITS, 0, NULL))
3607 ret = 0;
3608 else {
3609 if ((mask & GFP_NOFS) == GFP_NOFS)
3610 mask = GFP_NOFS;
3611 /*
3612 * at this point we can safely clear everything except the
3613 * locked bit and the nodatasum bit
3614 */
3615 ret = clear_extent_bit(tree, start, end,
3616 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
3617 0, 0, NULL, mask);
3618
3619 /* if clear_extent_bit failed for enomem reasons,
3620 * we can't allow the release to continue.
3621 */
3622 if (ret < 0)
3623 ret = 0;
3624 else
3625 ret = 1;
3626 }
3627 return ret;
3628}
3629
3630/*
3631 * a helper for releasepage. As long as there are no locked extents
3632 * in the range corresponding to the page, both state records and extent
3633 * map records are removed
3634 */
3635int try_release_extent_mapping(struct extent_map_tree *map,
3636 struct extent_io_tree *tree, struct page *page,
3637 gfp_t mask)
3638{
3639 struct extent_map *em;
3640 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
3641 u64 end = start + PAGE_CACHE_SIZE - 1;
3642
3643 if ((mask & __GFP_WAIT) &&
3644 page->mapping->host->i_size > 16 * 1024 * 1024) {
3645 u64 len;
3646 while (start <= end) {
3647 len = end - start + 1;
3648 write_lock(&map->lock);
3649 em = lookup_extent_mapping(map, start, len);
3650 if (!em) {
3651 write_unlock(&map->lock);
3652 break;
3653 }
3654 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
3655 em->start != start) {
3656 write_unlock(&map->lock);
3657 free_extent_map(em);
3658 break;
3659 }
3660 if (!test_range_bit(tree, em->start,
3661 extent_map_end(em) - 1,
3662 EXTENT_LOCKED | EXTENT_WRITEBACK,
3663 0, NULL)) {
3664 remove_extent_mapping(map, em);
3665 /* once for the rb tree */
3666 free_extent_map(em);
3667 }
3668 start = extent_map_end(em);
3669 write_unlock(&map->lock);
3670
3671 /* once for us */
3672 free_extent_map(em);
3673 }
3674 }
3675 return try_release_extent_state(map, tree, page, mask);
3676}
3677
3678/*
3679 * helper function for fiemap, which doesn't want to see any holes.
3680 * This maps until we find something past 'last'
3681 */
3682static struct extent_map *get_extent_skip_holes(struct inode *inode,
3683 u64 offset,
3684 u64 last,
3685 get_extent_t *get_extent)
3686{
3687 u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
3688 struct extent_map *em;
3689 u64 len;
3690
3691 if (offset >= last)
3692 return NULL;
3693
3694 while(1) {
3695 len = last - offset;
3696 if (len == 0)
3697 break;
3698 len = (len + sectorsize - 1) & ~(sectorsize - 1);
3699 em = get_extent(inode, NULL, 0, offset, len, 0);
3700 if (IS_ERR_OR_NULL(em))
3701 return em;
3702
3703 /* if this isn't a hole return it */
3704 if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
3705 em->block_start != EXTENT_MAP_HOLE) {
3706 return em;
3707 }
3708
3709 /* this is a hole, advance to the next extent */
3710 offset = extent_map_end(em);
3711 free_extent_map(em);
3712 if (offset >= last)
3713 break;
3714 }
3715 return NULL;
3716}
3717
3718int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
3719 __u64 start, __u64 len, get_extent_t *get_extent)
3720{
3721 int ret = 0;
3722 u64 off = start;
3723 u64 max = start + len;
3724 u32 flags = 0;
3725 u32 found_type;
3726 u64 last;
3727 u64 last_for_get_extent = 0;
3728 u64 disko = 0;
3729 u64 isize = i_size_read(inode);
3730 struct btrfs_key found_key;
3731 struct extent_map *em = NULL;
3732 struct extent_state *cached_state = NULL;
3733 struct btrfs_path *path;
3734 struct btrfs_file_extent_item *item;
3735 int end = 0;
3736 u64 em_start = 0;
3737 u64 em_len = 0;
3738 u64 em_end = 0;
3739 unsigned long emflags;
3740
3741 if (len == 0)
3742 return -EINVAL;
3743
3744 path = btrfs_alloc_path();
3745 if (!path)
3746 return -ENOMEM;
3747 path->leave_spinning = 1;
3748
3749 start = ALIGN(start, BTRFS_I(inode)->root->sectorsize);
3750 len = ALIGN(len, BTRFS_I(inode)->root->sectorsize);
3751
3752 /*
3753 * lookup the last file extent. We're not using i_size here
3754 * because there might be preallocation past i_size
3755 */
3756 ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
3757 path, btrfs_ino(inode), -1, 0);
3758 if (ret < 0) {
3759 btrfs_free_path(path);
3760 return ret;
3761 }
3762 WARN_ON(!ret);
3763 path->slots[0]--;
3764 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
3765 struct btrfs_file_extent_item);
3766 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
3767 found_type = btrfs_key_type(&found_key);
3768
3769 /* No extents, but there might be delalloc bits */
3770 if (found_key.objectid != btrfs_ino(inode) ||
3771 found_type != BTRFS_EXTENT_DATA_KEY) {
3772 /* have to trust i_size as the end */
3773 last = (u64)-1;
3774 last_for_get_extent = isize;
3775 } else {
3776 /*
3777 * remember the start of the last extent. There are a
3778 * bunch of different factors that go into the length of the
3779 * extent, so its much less complex to remember where it started
3780 */
3781 last = found_key.offset;
3782 last_for_get_extent = last + 1;
3783 }
3784 btrfs_free_path(path);
3785
3786 /*
3787 * we might have some extents allocated but more delalloc past those
3788 * extents. so, we trust isize unless the start of the last extent is
3789 * beyond isize
3790 */
3791 if (last < isize) {
3792 last = (u64)-1;
3793 last_for_get_extent = isize;
3794 }
3795
3796 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
3797 &cached_state);
3798
3799 em = get_extent_skip_holes(inode, start, last_for_get_extent,
3800 get_extent);
3801 if (!em)
3802 goto out;
3803 if (IS_ERR(em)) {
3804 ret = PTR_ERR(em);
3805 goto out;
3806 }
3807
3808 while (!end) {
3809 u64 offset_in_extent;
3810
3811 /* break if the extent we found is outside the range */
3812 if (em->start >= max || extent_map_end(em) < off)
3813 break;
3814
3815 /*
3816 * get_extent may return an extent that starts before our
3817 * requested range. We have to make sure the ranges
3818 * we return to fiemap always move forward and don't
3819 * overlap, so adjust the offsets here
3820 */
3821 em_start = max(em->start, off);
3822
3823 /*
3824 * record the offset from the start of the extent
3825 * for adjusting the disk offset below
3826 */
3827 offset_in_extent = em_start - em->start;
3828 em_end = extent_map_end(em);
3829 em_len = em_end - em_start;
3830 emflags = em->flags;
3831 disko = 0;
3832 flags = 0;
3833
3834 /*
3835 * bump off for our next call to get_extent
3836 */
3837 off = extent_map_end(em);
3838 if (off >= max)
3839 end = 1;
3840
3841 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
3842 end = 1;
3843 flags |= FIEMAP_EXTENT_LAST;
3844 } else if (em->block_start == EXTENT_MAP_INLINE) {
3845 flags |= (FIEMAP_EXTENT_DATA_INLINE |
3846 FIEMAP_EXTENT_NOT_ALIGNED);
3847 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
3848 flags |= (FIEMAP_EXTENT_DELALLOC |
3849 FIEMAP_EXTENT_UNKNOWN);
3850 } else {
3851 disko = em->block_start + offset_in_extent;
3852 }
3853 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
3854 flags |= FIEMAP_EXTENT_ENCODED;
3855
3856 free_extent_map(em);
3857 em = NULL;
3858 if ((em_start >= last) || em_len == (u64)-1 ||
3859 (last == (u64)-1 && isize <= em_end)) {
3860 flags |= FIEMAP_EXTENT_LAST;
3861 end = 1;
3862 }
3863
3864 /* now scan forward to see if this is really the last extent. */
3865 em = get_extent_skip_holes(inode, off, last_for_get_extent,
3866 get_extent);
3867 if (IS_ERR(em)) {
3868 ret = PTR_ERR(em);
3869 goto out;
3870 }
3871 if (!em) {
3872 flags |= FIEMAP_EXTENT_LAST;
3873 end = 1;
3874 }
3875 ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
3876 em_len, flags);
3877 if (ret)
3878 goto out_free;
3879 }
3880out_free:
3881 free_extent_map(em);
3882out:
3883 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len,
3884 &cached_state, GFP_NOFS);
3885 return ret;
3886}
3887
3888inline struct page *extent_buffer_page(struct extent_buffer *eb,
3889 unsigned long i)
3890{
3891 return eb->pages[i];
3892}
3893
3894inline unsigned long num_extent_pages(u64 start, u64 len)
3895{
3896 return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
3897 (start >> PAGE_CACHE_SHIFT);
3898}
3899
3900static void __free_extent_buffer(struct extent_buffer *eb)
3901{
3902#if LEAK_DEBUG
3903 unsigned long flags;
3904 spin_lock_irqsave(&leak_lock, flags);
3905 list_del(&eb->leak_list);
3906 spin_unlock_irqrestore(&leak_lock, flags);
3907#endif
3908 if (eb->pages && eb->pages != eb->inline_pages)
3909 kfree(eb->pages);
3910 kmem_cache_free(extent_buffer_cache, eb);
3911}
3912
3913static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
3914 u64 start,
3915 unsigned long len,
3916 gfp_t mask)
3917{
3918 struct extent_buffer *eb = NULL;
3919#if LEAK_DEBUG
3920 unsigned long flags;
3921#endif
3922
3923 eb = kmem_cache_zalloc(extent_buffer_cache, mask);
3924 if (eb == NULL)
3925 return NULL;
3926 eb->start = start;
3927 eb->len = len;
3928 eb->tree = tree;
3929 eb->bflags = 0;
3930 rwlock_init(&eb->lock);
3931 atomic_set(&eb->write_locks, 0);
3932 atomic_set(&eb->read_locks, 0);
3933 atomic_set(&eb->blocking_readers, 0);
3934 atomic_set(&eb->blocking_writers, 0);
3935 atomic_set(&eb->spinning_readers, 0);
3936 atomic_set(&eb->spinning_writers, 0);
3937 eb->lock_nested = 0;
3938 init_waitqueue_head(&eb->write_lock_wq);
3939 init_waitqueue_head(&eb->read_lock_wq);
3940
3941#if LEAK_DEBUG
3942 spin_lock_irqsave(&leak_lock, flags);
3943 list_add(&eb->leak_list, &buffers);
3944 spin_unlock_irqrestore(&leak_lock, flags);
3945#endif
3946 spin_lock_init(&eb->refs_lock);
3947 atomic_set(&eb->refs, 1);
3948 atomic_set(&eb->io_pages, 0);
3949
3950 if (len > MAX_INLINE_EXTENT_BUFFER_SIZE) {
3951 struct page **pages;
3952 int num_pages = (len + PAGE_CACHE_SIZE - 1) >>
3953 PAGE_CACHE_SHIFT;
3954 pages = kzalloc(num_pages, mask);
3955 if (!pages) {
3956 __free_extent_buffer(eb);
3957 return NULL;
3958 }
3959 eb->pages = pages;
3960 } else {
3961 eb->pages = eb->inline_pages;
3962 }
3963
3964 return eb;
3965}
3966
3967struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
3968{
3969 unsigned long i;
3970 struct page *p;
3971 struct extent_buffer *new;
3972 unsigned long num_pages = num_extent_pages(src->start, src->len);
3973
3974 new = __alloc_extent_buffer(NULL, src->start, src->len, GFP_ATOMIC);
3975 if (new == NULL)
3976 return NULL;
3977
3978 for (i = 0; i < num_pages; i++) {
3979 p = alloc_page(GFP_ATOMIC);
3980 BUG_ON(!p);
3981 attach_extent_buffer_page(new, p);
3982 WARN_ON(PageDirty(p));
3983 SetPageUptodate(p);
3984 new->pages[i] = p;
3985 }
3986
3987 copy_extent_buffer(new, src, 0, 0, src->len);
3988 set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
3989 set_bit(EXTENT_BUFFER_DUMMY, &new->bflags);
3990
3991 return new;
3992}
3993
3994struct extent_buffer *alloc_dummy_extent_buffer(u64 start, unsigned long len)
3995{
3996 struct extent_buffer *eb;
3997 unsigned long num_pages = num_extent_pages(0, len);
3998 unsigned long i;
3999
4000 eb = __alloc_extent_buffer(NULL, start, len, GFP_ATOMIC);
4001 if (!eb)
4002 return NULL;
4003
4004 for (i = 0; i < num_pages; i++) {
4005 eb->pages[i] = alloc_page(GFP_ATOMIC);
4006 if (!eb->pages[i])
4007 goto err;
4008 }
4009 set_extent_buffer_uptodate(eb);
4010 btrfs_set_header_nritems(eb, 0);
4011 set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4012
4013 return eb;
4014err:
4015 for (i--; i > 0; i--)
4016 __free_page(eb->pages[i]);
4017 __free_extent_buffer(eb);
4018 return NULL;
4019}
4020
4021static int extent_buffer_under_io(struct extent_buffer *eb)
4022{
4023 return (atomic_read(&eb->io_pages) ||
4024 test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
4025 test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4026}
4027
4028/*
4029 * Helper for releasing extent buffer page.
4030 */
4031static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
4032 unsigned long start_idx)
4033{
4034 unsigned long index;
4035 unsigned long num_pages;
4036 struct page *page;
4037 int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4038
4039 BUG_ON(extent_buffer_under_io(eb));
4040
4041 num_pages = num_extent_pages(eb->start, eb->len);
4042 index = start_idx + num_pages;
4043 if (start_idx >= index)
4044 return;
4045
4046 do {
4047 index--;
4048 page = extent_buffer_page(eb, index);
4049 if (page && mapped) {
4050 spin_lock(&page->mapping->private_lock);
4051 /*
4052 * We do this since we'll remove the pages after we've
4053 * removed the eb from the radix tree, so we could race
4054 * and have this page now attached to the new eb. So
4055 * only clear page_private if it's still connected to
4056 * this eb.
4057 */
4058 if (PagePrivate(page) &&
4059 page->private == (unsigned long)eb) {
4060 BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4061 BUG_ON(PageDirty(page));
4062 BUG_ON(PageWriteback(page));
4063 /*
4064 * We need to make sure we haven't be attached
4065 * to a new eb.
4066 */
4067 ClearPagePrivate(page);
4068 set_page_private(page, 0);
4069 /* One for the page private */
4070 page_cache_release(page);
4071 }
4072 spin_unlock(&page->mapping->private_lock);
4073
4074 }
4075 if (page) {
4076 /* One for when we alloced the page */
4077 page_cache_release(page);
4078 }
4079 } while (index != start_idx);
4080}
4081
4082/*
4083 * Helper for releasing the extent buffer.
4084 */
4085static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
4086{
4087 btrfs_release_extent_buffer_page(eb, 0);
4088 __free_extent_buffer(eb);
4089}
4090
4091static void check_buffer_tree_ref(struct extent_buffer *eb)
4092{
4093 /* the ref bit is tricky. We have to make sure it is set
4094 * if we have the buffer dirty. Otherwise the
4095 * code to free a buffer can end up dropping a dirty
4096 * page
4097 *
4098 * Once the ref bit is set, it won't go away while the
4099 * buffer is dirty or in writeback, and it also won't
4100 * go away while we have the reference count on the
4101 * eb bumped.
4102 *
4103 * We can't just set the ref bit without bumping the
4104 * ref on the eb because free_extent_buffer might
4105 * see the ref bit and try to clear it. If this happens
4106 * free_extent_buffer might end up dropping our original
4107 * ref by mistake and freeing the page before we are able
4108 * to add one more ref.
4109 *
4110 * So bump the ref count first, then set the bit. If someone
4111 * beat us to it, drop the ref we added.
4112 */
4113 if (!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
4114 atomic_inc(&eb->refs);
4115 if (test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4116 atomic_dec(&eb->refs);
4117 }
4118}
4119
4120static void mark_extent_buffer_accessed(struct extent_buffer *eb)
4121{
4122 unsigned long num_pages, i;
4123
4124 check_buffer_tree_ref(eb);
4125
4126 num_pages = num_extent_pages(eb->start, eb->len);
4127 for (i = 0; i < num_pages; i++) {
4128 struct page *p = extent_buffer_page(eb, i);
4129 mark_page_accessed(p);
4130 }
4131}
4132
4133struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
4134 u64 start, unsigned long len)
4135{
4136 unsigned long num_pages = num_extent_pages(start, len);
4137 unsigned long i;
4138 unsigned long index = start >> PAGE_CACHE_SHIFT;
4139 struct extent_buffer *eb;
4140 struct extent_buffer *exists = NULL;
4141 struct page *p;
4142 struct address_space *mapping = tree->mapping;
4143 int uptodate = 1;
4144 int ret;
4145
4146 rcu_read_lock();
4147 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
4148 if (eb && atomic_inc_not_zero(&eb->refs)) {
4149 rcu_read_unlock();
4150 mark_extent_buffer_accessed(eb);
4151 return eb;
4152 }
4153 rcu_read_unlock();
4154
4155 eb = __alloc_extent_buffer(tree, start, len, GFP_NOFS);
4156 if (!eb)
4157 return NULL;
4158
4159 for (i = 0; i < num_pages; i++, index++) {
4160 p = find_or_create_page(mapping, index, GFP_NOFS);
4161 if (!p) {
4162 WARN_ON(1);
4163 goto free_eb;
4164 }
4165
4166 spin_lock(&mapping->private_lock);
4167 if (PagePrivate(p)) {
4168 /*
4169 * We could have already allocated an eb for this page
4170 * and attached one so lets see if we can get a ref on
4171 * the existing eb, and if we can we know it's good and
4172 * we can just return that one, else we know we can just
4173 * overwrite page->private.
4174 */
4175 exists = (struct extent_buffer *)p->private;
4176 if (atomic_inc_not_zero(&exists->refs)) {
4177 spin_unlock(&mapping->private_lock);
4178 unlock_page(p);
4179 page_cache_release(p);
4180 mark_extent_buffer_accessed(exists);
4181 goto free_eb;
4182 }
4183
4184 /*
4185 * Do this so attach doesn't complain and we need to
4186 * drop the ref the old guy had.
4187 */
4188 ClearPagePrivate(p);
4189 WARN_ON(PageDirty(p));
4190 page_cache_release(p);
4191 }
4192 attach_extent_buffer_page(eb, p);
4193 spin_unlock(&mapping->private_lock);
4194 WARN_ON(PageDirty(p));
4195 mark_page_accessed(p);
4196 eb->pages[i] = p;
4197 if (!PageUptodate(p))
4198 uptodate = 0;
4199
4200 /*
4201 * see below about how we avoid a nasty race with release page
4202 * and why we unlock later
4203 */
4204 }
4205 if (uptodate)
4206 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4207again:
4208 ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
4209 if (ret)
4210 goto free_eb;
4211
4212 spin_lock(&tree->buffer_lock);
4213 ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
4214 if (ret == -EEXIST) {
4215 exists = radix_tree_lookup(&tree->buffer,
4216 start >> PAGE_CACHE_SHIFT);
4217 if (!atomic_inc_not_zero(&exists->refs)) {
4218 spin_unlock(&tree->buffer_lock);
4219 radix_tree_preload_end();
4220 exists = NULL;
4221 goto again;
4222 }
4223 spin_unlock(&tree->buffer_lock);
4224 radix_tree_preload_end();
4225 mark_extent_buffer_accessed(exists);
4226 goto free_eb;
4227 }
4228 /* add one reference for the tree */
4229 spin_lock(&eb->refs_lock);
4230 check_buffer_tree_ref(eb);
4231 spin_unlock(&eb->refs_lock);
4232 spin_unlock(&tree->buffer_lock);
4233 radix_tree_preload_end();
4234
4235 /*
4236 * there is a race where release page may have
4237 * tried to find this extent buffer in the radix
4238 * but failed. It will tell the VM it is safe to
4239 * reclaim the, and it will clear the page private bit.
4240 * We must make sure to set the page private bit properly
4241 * after the extent buffer is in the radix tree so
4242 * it doesn't get lost
4243 */
4244 SetPageChecked(eb->pages[0]);
4245 for (i = 1; i < num_pages; i++) {
4246 p = extent_buffer_page(eb, i);
4247 ClearPageChecked(p);
4248 unlock_page(p);
4249 }
4250 unlock_page(eb->pages[0]);
4251 return eb;
4252
4253free_eb:
4254 for (i = 0; i < num_pages; i++) {
4255 if (eb->pages[i])
4256 unlock_page(eb->pages[i]);
4257 }
4258
4259 WARN_ON(!atomic_dec_and_test(&eb->refs));
4260 btrfs_release_extent_buffer(eb);
4261 return exists;
4262}
4263
4264struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
4265 u64 start, unsigned long len)
4266{
4267 struct extent_buffer *eb;
4268
4269 rcu_read_lock();
4270 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
4271 if (eb && atomic_inc_not_zero(&eb->refs)) {
4272 rcu_read_unlock();
4273 mark_extent_buffer_accessed(eb);
4274 return eb;
4275 }
4276 rcu_read_unlock();
4277
4278 return NULL;
4279}
4280
4281static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
4282{
4283 struct extent_buffer *eb =
4284 container_of(head, struct extent_buffer, rcu_head);
4285
4286 __free_extent_buffer(eb);
4287}
4288
4289/* Expects to have eb->eb_lock already held */
4290static void release_extent_buffer(struct extent_buffer *eb, gfp_t mask)
4291{
4292 WARN_ON(atomic_read(&eb->refs) == 0);
4293 if (atomic_dec_and_test(&eb->refs)) {
4294 if (test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags)) {
4295 spin_unlock(&eb->refs_lock);
4296 } else {
4297 struct extent_io_tree *tree = eb->tree;
4298
4299 spin_unlock(&eb->refs_lock);
4300
4301 spin_lock(&tree->buffer_lock);
4302 radix_tree_delete(&tree->buffer,
4303 eb->start >> PAGE_CACHE_SHIFT);
4304 spin_unlock(&tree->buffer_lock);
4305 }
4306
4307 /* Should be safe to release our pages at this point */
4308 btrfs_release_extent_buffer_page(eb, 0);
4309
4310 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
4311 return;
4312 }
4313 spin_unlock(&eb->refs_lock);
4314}
4315
4316void free_extent_buffer(struct extent_buffer *eb)
4317{
4318 if (!eb)
4319 return;
4320
4321 spin_lock(&eb->refs_lock);
4322 if (atomic_read(&eb->refs) == 2 &&
4323 test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
4324 atomic_dec(&eb->refs);
4325
4326 if (atomic_read(&eb->refs) == 2 &&
4327 test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
4328 !extent_buffer_under_io(eb) &&
4329 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4330 atomic_dec(&eb->refs);
4331
4332 /*
4333 * I know this is terrible, but it's temporary until we stop tracking
4334 * the uptodate bits and such for the extent buffers.
4335 */
4336 release_extent_buffer(eb, GFP_ATOMIC);
4337}
4338
4339void free_extent_buffer_stale(struct extent_buffer *eb)
4340{
4341 if (!eb)
4342 return;
4343
4344 spin_lock(&eb->refs_lock);
4345 set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
4346
4347 if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
4348 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4349 atomic_dec(&eb->refs);
4350 release_extent_buffer(eb, GFP_NOFS);
4351}
4352
4353void clear_extent_buffer_dirty(struct extent_buffer *eb)
4354{
4355 unsigned long i;
4356 unsigned long num_pages;
4357 struct page *page;
4358
4359 num_pages = num_extent_pages(eb->start, eb->len);
4360
4361 for (i = 0; i < num_pages; i++) {
4362 page = extent_buffer_page(eb, i);
4363 if (!PageDirty(page))
4364 continue;
4365
4366 lock_page(page);
4367 WARN_ON(!PagePrivate(page));
4368
4369 clear_page_dirty_for_io(page);
4370 spin_lock_irq(&page->mapping->tree_lock);
4371 if (!PageDirty(page)) {
4372 radix_tree_tag_clear(&page->mapping->page_tree,
4373 page_index(page),
4374 PAGECACHE_TAG_DIRTY);
4375 }
4376 spin_unlock_irq(&page->mapping->tree_lock);
4377 ClearPageError(page);
4378 unlock_page(page);
4379 }
4380 WARN_ON(atomic_read(&eb->refs) == 0);
4381}
4382
4383int set_extent_buffer_dirty(struct extent_buffer *eb)
4384{
4385 unsigned long i;
4386 unsigned long num_pages;
4387 int was_dirty = 0;
4388
4389 check_buffer_tree_ref(eb);
4390
4391 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
4392
4393 num_pages = num_extent_pages(eb->start, eb->len);
4394 WARN_ON(atomic_read(&eb->refs) == 0);
4395 WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
4396
4397 for (i = 0; i < num_pages; i++)
4398 set_page_dirty(extent_buffer_page(eb, i));
4399 return was_dirty;
4400}
4401
4402static int range_straddles_pages(u64 start, u64 len)
4403{
4404 if (len < PAGE_CACHE_SIZE)
4405 return 1;
4406 if (start & (PAGE_CACHE_SIZE - 1))
4407 return 1;
4408 if ((start + len) & (PAGE_CACHE_SIZE - 1))
4409 return 1;
4410 return 0;
4411}
4412
4413int clear_extent_buffer_uptodate(struct extent_buffer *eb)
4414{
4415 unsigned long i;
4416 struct page *page;
4417 unsigned long num_pages;
4418
4419 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4420 num_pages = num_extent_pages(eb->start, eb->len);
4421 for (i = 0; i < num_pages; i++) {
4422 page = extent_buffer_page(eb, i);
4423 if (page)
4424 ClearPageUptodate(page);
4425 }
4426 return 0;
4427}
4428
4429int set_extent_buffer_uptodate(struct extent_buffer *eb)
4430{
4431 unsigned long i;
4432 struct page *page;
4433 unsigned long num_pages;
4434
4435 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4436 num_pages = num_extent_pages(eb->start, eb->len);
4437 for (i = 0; i < num_pages; i++) {
4438 page = extent_buffer_page(eb, i);
4439 SetPageUptodate(page);
4440 }
4441 return 0;
4442}
4443
4444int extent_range_uptodate(struct extent_io_tree *tree,
4445 u64 start, u64 end)
4446{
4447 struct page *page;
4448 int ret;
4449 int pg_uptodate = 1;
4450 int uptodate;
4451 unsigned long index;
4452
4453 if (range_straddles_pages(start, end - start + 1)) {
4454 ret = test_range_bit(tree, start, end,
4455 EXTENT_UPTODATE, 1, NULL);
4456 if (ret)
4457 return 1;
4458 }
4459 while (start <= end) {
4460 index = start >> PAGE_CACHE_SHIFT;
4461 page = find_get_page(tree->mapping, index);
4462 if (!page)
4463 return 1;
4464 uptodate = PageUptodate(page);
4465 page_cache_release(page);
4466 if (!uptodate) {
4467 pg_uptodate = 0;
4468 break;
4469 }
4470 start += PAGE_CACHE_SIZE;
4471 }
4472 return pg_uptodate;
4473}
4474
4475int extent_buffer_uptodate(struct extent_buffer *eb)
4476{
4477 return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4478}
4479
4480int read_extent_buffer_pages(struct extent_io_tree *tree,
4481 struct extent_buffer *eb, u64 start, int wait,
4482 get_extent_t *get_extent, int mirror_num)
4483{
4484 unsigned long i;
4485 unsigned long start_i;
4486 struct page *page;
4487 int err;
4488 int ret = 0;
4489 int locked_pages = 0;
4490 int all_uptodate = 1;
4491 unsigned long num_pages;
4492 unsigned long num_reads = 0;
4493 struct bio *bio = NULL;
4494 unsigned long bio_flags = 0;
4495
4496 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
4497 return 0;
4498
4499 if (start) {
4500 WARN_ON(start < eb->start);
4501 start_i = (start >> PAGE_CACHE_SHIFT) -
4502 (eb->start >> PAGE_CACHE_SHIFT);
4503 } else {
4504 start_i = 0;
4505 }
4506
4507 num_pages = num_extent_pages(eb->start, eb->len);
4508 for (i = start_i; i < num_pages; i++) {
4509 page = extent_buffer_page(eb, i);
4510 if (wait == WAIT_NONE) {
4511 if (!trylock_page(page))
4512 goto unlock_exit;
4513 } else {
4514 lock_page(page);
4515 }
4516 locked_pages++;
4517 if (!PageUptodate(page)) {
4518 num_reads++;
4519 all_uptodate = 0;
4520 }
4521 }
4522 if (all_uptodate) {
4523 if (start_i == 0)
4524 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4525 goto unlock_exit;
4526 }
4527
4528 clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
4529 eb->read_mirror = 0;
4530 atomic_set(&eb->io_pages, num_reads);
4531 for (i = start_i; i < num_pages; i++) {
4532 page = extent_buffer_page(eb, i);
4533 if (!PageUptodate(page)) {
4534 ClearPageError(page);
4535 err = __extent_read_full_page(tree, page,
4536 get_extent, &bio,
4537 mirror_num, &bio_flags);
4538 if (err)
4539 ret = err;
4540 } else {
4541 unlock_page(page);
4542 }
4543 }
4544
4545 if (bio) {
4546 err = submit_one_bio(READ, bio, mirror_num, bio_flags);
4547 if (err)
4548 return err;
4549 }
4550
4551 if (ret || wait != WAIT_COMPLETE)
4552 return ret;
4553
4554 for (i = start_i; i < num_pages; i++) {
4555 page = extent_buffer_page(eb, i);
4556 wait_on_page_locked(page);
4557 if (!PageUptodate(page))
4558 ret = -EIO;
4559 }
4560
4561 return ret;
4562
4563unlock_exit:
4564 i = start_i;
4565 while (locked_pages > 0) {
4566 page = extent_buffer_page(eb, i);
4567 i++;
4568 unlock_page(page);
4569 locked_pages--;
4570 }
4571 return ret;
4572}
4573
4574void read_extent_buffer(struct extent_buffer *eb, void *dstv,
4575 unsigned long start,
4576 unsigned long len)
4577{
4578 size_t cur;
4579 size_t offset;
4580 struct page *page;
4581 char *kaddr;
4582 char *dst = (char *)dstv;
4583 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
4584 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
4585
4586 WARN_ON(start > eb->len);
4587 WARN_ON(start + len > eb->start + eb->len);
4588
4589 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
4590
4591 while (len > 0) {
4592 page = extent_buffer_page(eb, i);
4593
4594 cur = min(len, (PAGE_CACHE_SIZE - offset));
4595 kaddr = page_address(page);
4596 memcpy(dst, kaddr + offset, cur);
4597
4598 dst += cur;
4599 len -= cur;
4600 offset = 0;
4601 i++;
4602 }
4603}
4604
4605int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
4606 unsigned long min_len, char **map,
4607 unsigned long *map_start,
4608 unsigned long *map_len)
4609{
4610 size_t offset = start & (PAGE_CACHE_SIZE - 1);
4611 char *kaddr;
4612 struct page *p;
4613 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
4614 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
4615 unsigned long end_i = (start_offset + start + min_len - 1) >>
4616 PAGE_CACHE_SHIFT;
4617
4618 if (i != end_i)
4619 return -EINVAL;
4620
4621 if (i == 0) {
4622 offset = start_offset;
4623 *map_start = 0;
4624 } else {
4625 offset = 0;
4626 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
4627 }
4628
4629 if (start + min_len > eb->len) {
4630 printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
4631 "wanted %lu %lu\n", (unsigned long long)eb->start,
4632 eb->len, start, min_len);
4633 WARN_ON(1);
4634 return -EINVAL;
4635 }
4636
4637 p = extent_buffer_page(eb, i);
4638 kaddr = page_address(p);
4639 *map = kaddr + offset;
4640 *map_len = PAGE_CACHE_SIZE - offset;
4641 return 0;
4642}
4643
4644int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
4645 unsigned long start,
4646 unsigned long len)
4647{
4648 size_t cur;
4649 size_t offset;
4650 struct page *page;
4651 char *kaddr;
4652 char *ptr = (char *)ptrv;
4653 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
4654 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
4655 int ret = 0;
4656
4657 WARN_ON(start > eb->len);
4658 WARN_ON(start + len > eb->start + eb->len);
4659
4660 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
4661
4662 while (len > 0) {
4663 page = extent_buffer_page(eb, i);
4664
4665 cur = min(len, (PAGE_CACHE_SIZE - offset));
4666
4667 kaddr = page_address(page);
4668 ret = memcmp(ptr, kaddr + offset, cur);
4669 if (ret)
4670 break;
4671
4672 ptr += cur;
4673 len -= cur;
4674 offset = 0;
4675 i++;
4676 }
4677 return ret;
4678}
4679
4680void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
4681 unsigned long start, unsigned long len)
4682{
4683 size_t cur;
4684 size_t offset;
4685 struct page *page;
4686 char *kaddr;
4687 char *src = (char *)srcv;
4688 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
4689 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
4690
4691 WARN_ON(start > eb->len);
4692 WARN_ON(start + len > eb->start + eb->len);
4693
4694 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
4695
4696 while (len > 0) {
4697 page = extent_buffer_page(eb, i);
4698 WARN_ON(!PageUptodate(page));
4699
4700 cur = min(len, PAGE_CACHE_SIZE - offset);
4701 kaddr = page_address(page);
4702 memcpy(kaddr + offset, src, cur);
4703
4704 src += cur;
4705 len -= cur;
4706 offset = 0;
4707 i++;
4708 }
4709}
4710
4711void memset_extent_buffer(struct extent_buffer *eb, char c,
4712 unsigned long start, unsigned long len)
4713{
4714 size_t cur;
4715 size_t offset;
4716 struct page *page;
4717 char *kaddr;
4718 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
4719 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
4720
4721 WARN_ON(start > eb->len);
4722 WARN_ON(start + len > eb->start + eb->len);
4723
4724 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
4725
4726 while (len > 0) {
4727 page = extent_buffer_page(eb, i);
4728 WARN_ON(!PageUptodate(page));
4729
4730 cur = min(len, PAGE_CACHE_SIZE - offset);
4731 kaddr = page_address(page);
4732 memset(kaddr + offset, c, cur);
4733
4734 len -= cur;
4735 offset = 0;
4736 i++;
4737 }
4738}
4739
4740void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
4741 unsigned long dst_offset, unsigned long src_offset,
4742 unsigned long len)
4743{
4744 u64 dst_len = dst->len;
4745 size_t cur;
4746 size_t offset;
4747 struct page *page;
4748 char *kaddr;
4749 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
4750 unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
4751
4752 WARN_ON(src->len != dst_len);
4753
4754 offset = (start_offset + dst_offset) &
4755 ((unsigned long)PAGE_CACHE_SIZE - 1);
4756
4757 while (len > 0) {
4758 page = extent_buffer_page(dst, i);
4759 WARN_ON(!PageUptodate(page));
4760
4761 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
4762
4763 kaddr = page_address(page);
4764 read_extent_buffer(src, kaddr + offset, src_offset, cur);
4765
4766 src_offset += cur;
4767 len -= cur;
4768 offset = 0;
4769 i++;
4770 }
4771}
4772
4773static void move_pages(struct page *dst_page, struct page *src_page,
4774 unsigned long dst_off, unsigned long src_off,
4775 unsigned long len)
4776{
4777 char *dst_kaddr = page_address(dst_page);
4778 if (dst_page == src_page) {
4779 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
4780 } else {
4781 char *src_kaddr = page_address(src_page);
4782 char *p = dst_kaddr + dst_off + len;
4783 char *s = src_kaddr + src_off + len;
4784
4785 while (len--)
4786 *--p = *--s;
4787 }
4788}
4789
4790static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
4791{
4792 unsigned long distance = (src > dst) ? src - dst : dst - src;
4793 return distance < len;
4794}
4795
4796static void copy_pages(struct page *dst_page, struct page *src_page,
4797 unsigned long dst_off, unsigned long src_off,
4798 unsigned long len)
4799{
4800 char *dst_kaddr = page_address(dst_page);
4801 char *src_kaddr;
4802 int must_memmove = 0;
4803
4804 if (dst_page != src_page) {
4805 src_kaddr = page_address(src_page);
4806 } else {
4807 src_kaddr = dst_kaddr;
4808 if (areas_overlap(src_off, dst_off, len))
4809 must_memmove = 1;
4810 }
4811
4812 if (must_memmove)
4813 memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
4814 else
4815 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
4816}
4817
4818void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
4819 unsigned long src_offset, unsigned long len)
4820{
4821 size_t cur;
4822 size_t dst_off_in_page;
4823 size_t src_off_in_page;
4824 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
4825 unsigned long dst_i;
4826 unsigned long src_i;
4827
4828 if (src_offset + len > dst->len) {
4829 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
4830 "len %lu dst len %lu\n", src_offset, len, dst->len);
4831 BUG_ON(1);
4832 }
4833 if (dst_offset + len > dst->len) {
4834 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
4835 "len %lu dst len %lu\n", dst_offset, len, dst->len);
4836 BUG_ON(1);
4837 }
4838
4839 while (len > 0) {
4840 dst_off_in_page = (start_offset + dst_offset) &
4841 ((unsigned long)PAGE_CACHE_SIZE - 1);
4842 src_off_in_page = (start_offset + src_offset) &
4843 ((unsigned long)PAGE_CACHE_SIZE - 1);
4844
4845 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
4846 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
4847
4848 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
4849 src_off_in_page));
4850 cur = min_t(unsigned long, cur,
4851 (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
4852
4853 copy_pages(extent_buffer_page(dst, dst_i),
4854 extent_buffer_page(dst, src_i),
4855 dst_off_in_page, src_off_in_page, cur);
4856
4857 src_offset += cur;
4858 dst_offset += cur;
4859 len -= cur;
4860 }
4861}
4862
4863void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
4864 unsigned long src_offset, unsigned long len)
4865{
4866 size_t cur;
4867 size_t dst_off_in_page;
4868 size_t src_off_in_page;
4869 unsigned long dst_end = dst_offset + len - 1;
4870 unsigned long src_end = src_offset + len - 1;
4871 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
4872 unsigned long dst_i;
4873 unsigned long src_i;
4874
4875 if (src_offset + len > dst->len) {
4876 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
4877 "len %lu len %lu\n", src_offset, len, dst->len);
4878 BUG_ON(1);
4879 }
4880 if (dst_offset + len > dst->len) {
4881 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
4882 "len %lu len %lu\n", dst_offset, len, dst->len);
4883 BUG_ON(1);
4884 }
4885 if (dst_offset < src_offset) {
4886 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
4887 return;
4888 }
4889 while (len > 0) {
4890 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
4891 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
4892
4893 dst_off_in_page = (start_offset + dst_end) &
4894 ((unsigned long)PAGE_CACHE_SIZE - 1);
4895 src_off_in_page = (start_offset + src_end) &
4896 ((unsigned long)PAGE_CACHE_SIZE - 1);
4897
4898 cur = min_t(unsigned long, len, src_off_in_page + 1);
4899 cur = min(cur, dst_off_in_page + 1);
4900 move_pages(extent_buffer_page(dst, dst_i),
4901 extent_buffer_page(dst, src_i),
4902 dst_off_in_page - cur + 1,
4903 src_off_in_page - cur + 1, cur);
4904
4905 dst_end -= cur;
4906 src_end -= cur;
4907 len -= cur;
4908 }
4909}
4910
4911int try_release_extent_buffer(struct page *page, gfp_t mask)
4912{
4913 struct extent_buffer *eb;
4914
4915 /*
4916 * We need to make sure noboody is attaching this page to an eb right
4917 * now.
4918 */
4919 spin_lock(&page->mapping->private_lock);
4920 if (!PagePrivate(page)) {
4921 spin_unlock(&page->mapping->private_lock);
4922 return 1;
4923 }
4924
4925 eb = (struct extent_buffer *)page->private;
4926 BUG_ON(!eb);
4927
4928 /*
4929 * This is a little awful but should be ok, we need to make sure that
4930 * the eb doesn't disappear out from under us while we're looking at
4931 * this page.
4932 */
4933 spin_lock(&eb->refs_lock);
4934 if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
4935 spin_unlock(&eb->refs_lock);
4936 spin_unlock(&page->mapping->private_lock);
4937 return 0;
4938 }
4939 spin_unlock(&page->mapping->private_lock);
4940
4941 if ((mask & GFP_NOFS) == GFP_NOFS)
4942 mask = GFP_NOFS;
4943
4944 /*
4945 * If tree ref isn't set then we know the ref on this eb is a real ref,
4946 * so just return, this page will likely be freed soon anyway.
4947 */
4948 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
4949 spin_unlock(&eb->refs_lock);
4950 return 0;
4951 }
4952 release_extent_buffer(eb, mask);
4953
4954 return 1;
4955}
1#include <linux/bitops.h>
2#include <linux/slab.h>
3#include <linux/bio.h>
4#include <linux/mm.h>
5#include <linux/pagemap.h>
6#include <linux/page-flags.h>
7#include <linux/module.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"
17#include "compat.h"
18#include "ctree.h"
19#include "btrfs_inode.h"
20
21static struct kmem_cache *extent_state_cache;
22static struct kmem_cache *extent_buffer_cache;
23
24static LIST_HEAD(buffers);
25static LIST_HEAD(states);
26
27#define LEAK_DEBUG 0
28#if LEAK_DEBUG
29static DEFINE_SPINLOCK(leak_lock);
30#endif
31
32#define BUFFER_LRU_MAX 64
33
34struct tree_entry {
35 u64 start;
36 u64 end;
37 struct rb_node rb_node;
38};
39
40struct extent_page_data {
41 struct bio *bio;
42 struct extent_io_tree *tree;
43 get_extent_t *get_extent;
44
45 /* tells writepage not to lock the state bits for this range
46 * it still does the unlocking
47 */
48 unsigned int extent_locked:1;
49
50 /* tells the submit_bio code to use a WRITE_SYNC */
51 unsigned int sync_io:1;
52};
53
54int __init extent_io_init(void)
55{
56 extent_state_cache = kmem_cache_create("extent_state",
57 sizeof(struct extent_state), 0,
58 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
59 if (!extent_state_cache)
60 return -ENOMEM;
61
62 extent_buffer_cache = kmem_cache_create("extent_buffers",
63 sizeof(struct extent_buffer), 0,
64 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
65 if (!extent_buffer_cache)
66 goto free_state_cache;
67 return 0;
68
69free_state_cache:
70 kmem_cache_destroy(extent_state_cache);
71 return -ENOMEM;
72}
73
74void extent_io_exit(void)
75{
76 struct extent_state *state;
77 struct extent_buffer *eb;
78
79 while (!list_empty(&states)) {
80 state = list_entry(states.next, struct extent_state, leak_list);
81 printk(KERN_ERR "btrfs state leak: start %llu end %llu "
82 "state %lu in tree %p refs %d\n",
83 (unsigned long long)state->start,
84 (unsigned long long)state->end,
85 state->state, state->tree, atomic_read(&state->refs));
86 list_del(&state->leak_list);
87 kmem_cache_free(extent_state_cache, state);
88
89 }
90
91 while (!list_empty(&buffers)) {
92 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
93 printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
94 "refs %d\n", (unsigned long long)eb->start,
95 eb->len, atomic_read(&eb->refs));
96 list_del(&eb->leak_list);
97 kmem_cache_free(extent_buffer_cache, eb);
98 }
99 if (extent_state_cache)
100 kmem_cache_destroy(extent_state_cache);
101 if (extent_buffer_cache)
102 kmem_cache_destroy(extent_buffer_cache);
103}
104
105void extent_io_tree_init(struct extent_io_tree *tree,
106 struct address_space *mapping)
107{
108 tree->state = RB_ROOT;
109 INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
110 tree->ops = NULL;
111 tree->dirty_bytes = 0;
112 spin_lock_init(&tree->lock);
113 spin_lock_init(&tree->buffer_lock);
114 tree->mapping = mapping;
115}
116
117static struct extent_state *alloc_extent_state(gfp_t mask)
118{
119 struct extent_state *state;
120#if LEAK_DEBUG
121 unsigned long flags;
122#endif
123
124 state = kmem_cache_alloc(extent_state_cache, mask);
125 if (!state)
126 return state;
127 state->state = 0;
128 state->private = 0;
129 state->tree = NULL;
130#if LEAK_DEBUG
131 spin_lock_irqsave(&leak_lock, flags);
132 list_add(&state->leak_list, &states);
133 spin_unlock_irqrestore(&leak_lock, flags);
134#endif
135 atomic_set(&state->refs, 1);
136 init_waitqueue_head(&state->wq);
137 return state;
138}
139
140void free_extent_state(struct extent_state *state)
141{
142 if (!state)
143 return;
144 if (atomic_dec_and_test(&state->refs)) {
145#if LEAK_DEBUG
146 unsigned long flags;
147#endif
148 WARN_ON(state->tree);
149#if LEAK_DEBUG
150 spin_lock_irqsave(&leak_lock, flags);
151 list_del(&state->leak_list);
152 spin_unlock_irqrestore(&leak_lock, flags);
153#endif
154 kmem_cache_free(extent_state_cache, state);
155 }
156}
157
158static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
159 struct rb_node *node)
160{
161 struct rb_node **p = &root->rb_node;
162 struct rb_node *parent = NULL;
163 struct tree_entry *entry;
164
165 while (*p) {
166 parent = *p;
167 entry = rb_entry(parent, struct tree_entry, rb_node);
168
169 if (offset < entry->start)
170 p = &(*p)->rb_left;
171 else if (offset > entry->end)
172 p = &(*p)->rb_right;
173 else
174 return parent;
175 }
176
177 entry = rb_entry(node, struct tree_entry, rb_node);
178 rb_link_node(node, parent, p);
179 rb_insert_color(node, root);
180 return NULL;
181}
182
183static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
184 struct rb_node **prev_ret,
185 struct rb_node **next_ret)
186{
187 struct rb_root *root = &tree->state;
188 struct rb_node *n = root->rb_node;
189 struct rb_node *prev = NULL;
190 struct rb_node *orig_prev = NULL;
191 struct tree_entry *entry;
192 struct tree_entry *prev_entry = NULL;
193
194 while (n) {
195 entry = rb_entry(n, struct tree_entry, rb_node);
196 prev = n;
197 prev_entry = entry;
198
199 if (offset < entry->start)
200 n = n->rb_left;
201 else if (offset > entry->end)
202 n = n->rb_right;
203 else
204 return n;
205 }
206
207 if (prev_ret) {
208 orig_prev = prev;
209 while (prev && offset > prev_entry->end) {
210 prev = rb_next(prev);
211 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
212 }
213 *prev_ret = prev;
214 prev = orig_prev;
215 }
216
217 if (next_ret) {
218 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
219 while (prev && offset < prev_entry->start) {
220 prev = rb_prev(prev);
221 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
222 }
223 *next_ret = prev;
224 }
225 return NULL;
226}
227
228static inline struct rb_node *tree_search(struct extent_io_tree *tree,
229 u64 offset)
230{
231 struct rb_node *prev = NULL;
232 struct rb_node *ret;
233
234 ret = __etree_search(tree, offset, &prev, NULL);
235 if (!ret)
236 return prev;
237 return ret;
238}
239
240static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
241 struct extent_state *other)
242{
243 if (tree->ops && tree->ops->merge_extent_hook)
244 tree->ops->merge_extent_hook(tree->mapping->host, new,
245 other);
246}
247
248/*
249 * utility function to look for merge candidates inside a given range.
250 * Any extents with matching state are merged together into a single
251 * extent in the tree. Extents with EXTENT_IO in their state field
252 * are not merged because the end_io handlers need to be able to do
253 * operations on them without sleeping (or doing allocations/splits).
254 *
255 * This should be called with the tree lock held.
256 */
257static void merge_state(struct extent_io_tree *tree,
258 struct extent_state *state)
259{
260 struct extent_state *other;
261 struct rb_node *other_node;
262
263 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
264 return;
265
266 other_node = rb_prev(&state->rb_node);
267 if (other_node) {
268 other = rb_entry(other_node, struct extent_state, rb_node);
269 if (other->end == state->start - 1 &&
270 other->state == state->state) {
271 merge_cb(tree, state, other);
272 state->start = other->start;
273 other->tree = NULL;
274 rb_erase(&other->rb_node, &tree->state);
275 free_extent_state(other);
276 }
277 }
278 other_node = rb_next(&state->rb_node);
279 if (other_node) {
280 other = rb_entry(other_node, struct extent_state, rb_node);
281 if (other->start == state->end + 1 &&
282 other->state == state->state) {
283 merge_cb(tree, state, other);
284 state->end = other->end;
285 other->tree = NULL;
286 rb_erase(&other->rb_node, &tree->state);
287 free_extent_state(other);
288 }
289 }
290}
291
292static void set_state_cb(struct extent_io_tree *tree,
293 struct extent_state *state, int *bits)
294{
295 if (tree->ops && tree->ops->set_bit_hook)
296 tree->ops->set_bit_hook(tree->mapping->host, state, bits);
297}
298
299static void clear_state_cb(struct extent_io_tree *tree,
300 struct extent_state *state, int *bits)
301{
302 if (tree->ops && tree->ops->clear_bit_hook)
303 tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
304}
305
306static void set_state_bits(struct extent_io_tree *tree,
307 struct extent_state *state, int *bits);
308
309/*
310 * insert an extent_state struct into the tree. 'bits' are set on the
311 * struct before it is inserted.
312 *
313 * This may return -EEXIST if the extent is already there, in which case the
314 * state struct is freed.
315 *
316 * The tree lock is not taken internally. This is a utility function and
317 * probably isn't what you want to call (see set/clear_extent_bit).
318 */
319static int insert_state(struct extent_io_tree *tree,
320 struct extent_state *state, u64 start, u64 end,
321 int *bits)
322{
323 struct rb_node *node;
324
325 if (end < start) {
326 printk(KERN_ERR "btrfs end < start %llu %llu\n",
327 (unsigned long long)end,
328 (unsigned long long)start);
329 WARN_ON(1);
330 }
331 state->start = start;
332 state->end = end;
333
334 set_state_bits(tree, state, bits);
335
336 node = tree_insert(&tree->state, end, &state->rb_node);
337 if (node) {
338 struct extent_state *found;
339 found = rb_entry(node, struct extent_state, rb_node);
340 printk(KERN_ERR "btrfs found node %llu %llu on insert of "
341 "%llu %llu\n", (unsigned long long)found->start,
342 (unsigned long long)found->end,
343 (unsigned long long)start, (unsigned long long)end);
344 return -EEXIST;
345 }
346 state->tree = tree;
347 merge_state(tree, state);
348 return 0;
349}
350
351static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
352 u64 split)
353{
354 if (tree->ops && tree->ops->split_extent_hook)
355 tree->ops->split_extent_hook(tree->mapping->host, orig, split);
356}
357
358/*
359 * split a given extent state struct in two, inserting the preallocated
360 * struct 'prealloc' as the newly created second half. 'split' indicates an
361 * offset inside 'orig' where it should be split.
362 *
363 * Before calling,
364 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
365 * are two extent state structs in the tree:
366 * prealloc: [orig->start, split - 1]
367 * orig: [ split, orig->end ]
368 *
369 * The tree locks are not taken by this function. They need to be held
370 * by the caller.
371 */
372static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
373 struct extent_state *prealloc, u64 split)
374{
375 struct rb_node *node;
376
377 split_cb(tree, orig, split);
378
379 prealloc->start = orig->start;
380 prealloc->end = split - 1;
381 prealloc->state = orig->state;
382 orig->start = split;
383
384 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
385 if (node) {
386 free_extent_state(prealloc);
387 return -EEXIST;
388 }
389 prealloc->tree = tree;
390 return 0;
391}
392
393/*
394 * utility function to clear some bits in an extent state struct.
395 * it will optionally wake up any one waiting on this state (wake == 1), or
396 * forcibly remove the state from the tree (delete == 1).
397 *
398 * If no bits are set on the state struct after clearing things, the
399 * struct is freed and removed from the tree
400 */
401static int clear_state_bit(struct extent_io_tree *tree,
402 struct extent_state *state,
403 int *bits, int wake)
404{
405 int bits_to_clear = *bits & ~EXTENT_CTLBITS;
406 int ret = state->state & bits_to_clear;
407
408 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
409 u64 range = state->end - state->start + 1;
410 WARN_ON(range > tree->dirty_bytes);
411 tree->dirty_bytes -= range;
412 }
413 clear_state_cb(tree, state, bits);
414 state->state &= ~bits_to_clear;
415 if (wake)
416 wake_up(&state->wq);
417 if (state->state == 0) {
418 if (state->tree) {
419 rb_erase(&state->rb_node, &tree->state);
420 state->tree = NULL;
421 free_extent_state(state);
422 } else {
423 WARN_ON(1);
424 }
425 } else {
426 merge_state(tree, state);
427 }
428 return ret;
429}
430
431static struct extent_state *
432alloc_extent_state_atomic(struct extent_state *prealloc)
433{
434 if (!prealloc)
435 prealloc = alloc_extent_state(GFP_ATOMIC);
436
437 return prealloc;
438}
439
440/*
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.
444 *
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).
447 *
448 * the range [start, end] is inclusive.
449 *
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.
452 */
453int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
454 int bits, int wake, int delete,
455 struct extent_state **cached_state,
456 gfp_t mask)
457{
458 struct extent_state *state;
459 struct extent_state *cached;
460 struct extent_state *prealloc = NULL;
461 struct rb_node *next_node;
462 struct rb_node *node;
463 u64 last_end;
464 int err;
465 int set = 0;
466 int clear = 0;
467
468 if (delete)
469 bits |= ~EXTENT_CTLBITS;
470 bits |= EXTENT_FIRST_DELALLOC;
471
472 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
473 clear = 1;
474again:
475 if (!prealloc && (mask & __GFP_WAIT)) {
476 prealloc = alloc_extent_state(mask);
477 if (!prealloc)
478 return -ENOMEM;
479 }
480
481 spin_lock(&tree->lock);
482 if (cached_state) {
483 cached = *cached_state;
484
485 if (clear) {
486 *cached_state = NULL;
487 cached_state = NULL;
488 }
489
490 if (cached && cached->tree && cached->start <= start &&
491 cached->end > start) {
492 if (clear)
493 atomic_dec(&cached->refs);
494 state = cached;
495 goto hit_next;
496 }
497 if (clear)
498 free_extent_state(cached);
499 }
500 /*
501 * this search will find the extents that end after
502 * our range starts
503 */
504 node = tree_search(tree, start);
505 if (!node)
506 goto out;
507 state = rb_entry(node, struct extent_state, rb_node);
508hit_next:
509 if (state->start > end)
510 goto out;
511 WARN_ON(state->end < start);
512 last_end = state->end;
513
514 /*
515 * | ---- desired range ---- |
516 * | state | or
517 * | ------------- state -------------- |
518 *
519 * We need to split the extent we found, and may flip
520 * bits on second half.
521 *
522 * If the extent we found extends past our range, we
523 * just split and search again. It'll get split again
524 * the next time though.
525 *
526 * If the extent we found is inside our range, we clear
527 * the desired bit on it.
528 */
529
530 if (state->start < start) {
531 prealloc = alloc_extent_state_atomic(prealloc);
532 BUG_ON(!prealloc);
533 err = split_state(tree, state, prealloc, start);
534 BUG_ON(err == -EEXIST);
535 prealloc = NULL;
536 if (err)
537 goto out;
538 if (state->end <= end) {
539 set |= clear_state_bit(tree, state, &bits, wake);
540 if (last_end == (u64)-1)
541 goto out;
542 start = last_end + 1;
543 }
544 goto search_again;
545 }
546 /*
547 * | ---- desired range ---- |
548 * | state |
549 * We need to split the extent, and clear the bit
550 * on the first half
551 */
552 if (state->start <= end && state->end > end) {
553 prealloc = alloc_extent_state_atomic(prealloc);
554 BUG_ON(!prealloc);
555 err = split_state(tree, state, prealloc, end + 1);
556 BUG_ON(err == -EEXIST);
557 if (wake)
558 wake_up(&state->wq);
559
560 set |= clear_state_bit(tree, prealloc, &bits, wake);
561
562 prealloc = NULL;
563 goto out;
564 }
565
566 if (state->end < end && prealloc && !need_resched())
567 next_node = rb_next(&state->rb_node);
568 else
569 next_node = NULL;
570
571 set |= clear_state_bit(tree, state, &bits, wake);
572 if (last_end == (u64)-1)
573 goto out;
574 start = last_end + 1;
575 if (start <= end && next_node) {
576 state = rb_entry(next_node, struct extent_state,
577 rb_node);
578 if (state->start == start)
579 goto hit_next;
580 }
581 goto search_again;
582
583out:
584 spin_unlock(&tree->lock);
585 if (prealloc)
586 free_extent_state(prealloc);
587
588 return set;
589
590search_again:
591 if (start > end)
592 goto out;
593 spin_unlock(&tree->lock);
594 if (mask & __GFP_WAIT)
595 cond_resched();
596 goto again;
597}
598
599static int wait_on_state(struct extent_io_tree *tree,
600 struct extent_state *state)
601 __releases(tree->lock)
602 __acquires(tree->lock)
603{
604 DEFINE_WAIT(wait);
605 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
606 spin_unlock(&tree->lock);
607 schedule();
608 spin_lock(&tree->lock);
609 finish_wait(&state->wq, &wait);
610 return 0;
611}
612
613/*
614 * waits for one or more bits to clear on a range in the state tree.
615 * The range [start, end] is inclusive.
616 * The tree lock is taken by this function
617 */
618int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
619{
620 struct extent_state *state;
621 struct rb_node *node;
622
623 spin_lock(&tree->lock);
624again:
625 while (1) {
626 /*
627 * this search will find all the extents that end after
628 * our range starts
629 */
630 node = tree_search(tree, start);
631 if (!node)
632 break;
633
634 state = rb_entry(node, struct extent_state, rb_node);
635
636 if (state->start > end)
637 goto out;
638
639 if (state->state & bits) {
640 start = state->start;
641 atomic_inc(&state->refs);
642 wait_on_state(tree, state);
643 free_extent_state(state);
644 goto again;
645 }
646 start = state->end + 1;
647
648 if (start > end)
649 break;
650
651 cond_resched_lock(&tree->lock);
652 }
653out:
654 spin_unlock(&tree->lock);
655 return 0;
656}
657
658static void set_state_bits(struct extent_io_tree *tree,
659 struct extent_state *state,
660 int *bits)
661{
662 int bits_to_set = *bits & ~EXTENT_CTLBITS;
663
664 set_state_cb(tree, state, bits);
665 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
666 u64 range = state->end - state->start + 1;
667 tree->dirty_bytes += range;
668 }
669 state->state |= bits_to_set;
670}
671
672static void cache_state(struct extent_state *state,
673 struct extent_state **cached_ptr)
674{
675 if (cached_ptr && !(*cached_ptr)) {
676 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
677 *cached_ptr = state;
678 atomic_inc(&state->refs);
679 }
680 }
681}
682
683static void uncache_state(struct extent_state **cached_ptr)
684{
685 if (cached_ptr && (*cached_ptr)) {
686 struct extent_state *state = *cached_ptr;
687 *cached_ptr = NULL;
688 free_extent_state(state);
689 }
690}
691
692/*
693 * set some bits on a range in the tree. This may require allocations or
694 * sleeping, so the gfp mask is used to indicate what is allowed.
695 *
696 * If any of the exclusive bits are set, this will fail with -EEXIST if some
697 * part of the range already has the desired bits set. The start of the
698 * existing range is returned in failed_start in this case.
699 *
700 * [start, end] is inclusive This takes the tree lock.
701 */
702
703int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
704 int bits, int exclusive_bits, u64 *failed_start,
705 struct extent_state **cached_state, gfp_t mask)
706{
707 struct extent_state *state;
708 struct extent_state *prealloc = NULL;
709 struct rb_node *node;
710 int err = 0;
711 u64 last_start;
712 u64 last_end;
713
714 bits |= EXTENT_FIRST_DELALLOC;
715again:
716 if (!prealloc && (mask & __GFP_WAIT)) {
717 prealloc = alloc_extent_state(mask);
718 BUG_ON(!prealloc);
719 }
720
721 spin_lock(&tree->lock);
722 if (cached_state && *cached_state) {
723 state = *cached_state;
724 if (state->start <= start && state->end > start &&
725 state->tree) {
726 node = &state->rb_node;
727 goto hit_next;
728 }
729 }
730 /*
731 * this search will find all the extents that end after
732 * our range starts.
733 */
734 node = tree_search(tree, start);
735 if (!node) {
736 prealloc = alloc_extent_state_atomic(prealloc);
737 BUG_ON(!prealloc);
738 err = insert_state(tree, prealloc, start, end, &bits);
739 prealloc = NULL;
740 BUG_ON(err == -EEXIST);
741 goto out;
742 }
743 state = rb_entry(node, struct extent_state, rb_node);
744hit_next:
745 last_start = state->start;
746 last_end = state->end;
747
748 /*
749 * | ---- desired range ---- |
750 * | state |
751 *
752 * Just lock what we found and keep going
753 */
754 if (state->start == start && state->end <= end) {
755 struct rb_node *next_node;
756 if (state->state & exclusive_bits) {
757 *failed_start = state->start;
758 err = -EEXIST;
759 goto out;
760 }
761
762 set_state_bits(tree, state, &bits);
763
764 cache_state(state, cached_state);
765 merge_state(tree, state);
766 if (last_end == (u64)-1)
767 goto out;
768
769 start = last_end + 1;
770 next_node = rb_next(&state->rb_node);
771 if (next_node && start < end && prealloc && !need_resched()) {
772 state = rb_entry(next_node, struct extent_state,
773 rb_node);
774 if (state->start == start)
775 goto hit_next;
776 }
777 goto search_again;
778 }
779
780 /*
781 * | ---- desired range ---- |
782 * | state |
783 * or
784 * | ------------- state -------------- |
785 *
786 * We need to split the extent we found, and may flip bits on
787 * second half.
788 *
789 * If the extent we found extends past our
790 * range, we just split and search again. It'll get split
791 * again the next time though.
792 *
793 * If the extent we found is inside our range, we set the
794 * desired bit on it.
795 */
796 if (state->start < start) {
797 if (state->state & exclusive_bits) {
798 *failed_start = start;
799 err = -EEXIST;
800 goto out;
801 }
802
803 prealloc = alloc_extent_state_atomic(prealloc);
804 BUG_ON(!prealloc);
805 err = split_state(tree, state, prealloc, start);
806 BUG_ON(err == -EEXIST);
807 prealloc = NULL;
808 if (err)
809 goto out;
810 if (state->end <= end) {
811 set_state_bits(tree, state, &bits);
812 cache_state(state, cached_state);
813 merge_state(tree, state);
814 if (last_end == (u64)-1)
815 goto out;
816 start = last_end + 1;
817 }
818 goto search_again;
819 }
820 /*
821 * | ---- desired range ---- |
822 * | state | or | state |
823 *
824 * There's a hole, we need to insert something in it and
825 * ignore the extent we found.
826 */
827 if (state->start > start) {
828 u64 this_end;
829 if (end < last_start)
830 this_end = end;
831 else
832 this_end = last_start - 1;
833
834 prealloc = alloc_extent_state_atomic(prealloc);
835 BUG_ON(!prealloc);
836
837 /*
838 * Avoid to free 'prealloc' if it can be merged with
839 * the later extent.
840 */
841 err = insert_state(tree, prealloc, start, this_end,
842 &bits);
843 BUG_ON(err == -EEXIST);
844 if (err) {
845 free_extent_state(prealloc);
846 prealloc = NULL;
847 goto out;
848 }
849 cache_state(prealloc, cached_state);
850 prealloc = NULL;
851 start = this_end + 1;
852 goto search_again;
853 }
854 /*
855 * | ---- desired range ---- |
856 * | state |
857 * We need to split the extent, and set the bit
858 * on the first half
859 */
860 if (state->start <= end && state->end > end) {
861 if (state->state & exclusive_bits) {
862 *failed_start = start;
863 err = -EEXIST;
864 goto out;
865 }
866
867 prealloc = alloc_extent_state_atomic(prealloc);
868 BUG_ON(!prealloc);
869 err = split_state(tree, state, prealloc, end + 1);
870 BUG_ON(err == -EEXIST);
871
872 set_state_bits(tree, prealloc, &bits);
873 cache_state(prealloc, cached_state);
874 merge_state(tree, prealloc);
875 prealloc = NULL;
876 goto out;
877 }
878
879 goto search_again;
880
881out:
882 spin_unlock(&tree->lock);
883 if (prealloc)
884 free_extent_state(prealloc);
885
886 return err;
887
888search_again:
889 if (start > end)
890 goto out;
891 spin_unlock(&tree->lock);
892 if (mask & __GFP_WAIT)
893 cond_resched();
894 goto again;
895}
896
897/* wrappers around set/clear extent bit */
898int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
899 gfp_t mask)
900{
901 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
902 NULL, mask);
903}
904
905int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
906 int bits, gfp_t mask)
907{
908 return set_extent_bit(tree, start, end, bits, 0, NULL,
909 NULL, mask);
910}
911
912int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
913 int bits, gfp_t mask)
914{
915 return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
916}
917
918int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
919 struct extent_state **cached_state, gfp_t mask)
920{
921 return set_extent_bit(tree, start, end,
922 EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
923 0, NULL, cached_state, mask);
924}
925
926int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
927 gfp_t mask)
928{
929 return clear_extent_bit(tree, start, end,
930 EXTENT_DIRTY | EXTENT_DELALLOC |
931 EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
932}
933
934int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
935 gfp_t mask)
936{
937 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
938 NULL, mask);
939}
940
941int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
942 struct extent_state **cached_state, gfp_t mask)
943{
944 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0,
945 NULL, cached_state, mask);
946}
947
948static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
949 u64 end, struct extent_state **cached_state,
950 gfp_t mask)
951{
952 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
953 cached_state, mask);
954}
955
956/*
957 * either insert or lock state struct between start and end use mask to tell
958 * us if waiting is desired.
959 */
960int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
961 int bits, struct extent_state **cached_state, gfp_t mask)
962{
963 int err;
964 u64 failed_start;
965 while (1) {
966 err = set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
967 EXTENT_LOCKED, &failed_start,
968 cached_state, mask);
969 if (err == -EEXIST && (mask & __GFP_WAIT)) {
970 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
971 start = failed_start;
972 } else {
973 break;
974 }
975 WARN_ON(start > end);
976 }
977 return err;
978}
979
980int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
981{
982 return lock_extent_bits(tree, start, end, 0, NULL, mask);
983}
984
985int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
986 gfp_t mask)
987{
988 int err;
989 u64 failed_start;
990
991 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
992 &failed_start, NULL, mask);
993 if (err == -EEXIST) {
994 if (failed_start > start)
995 clear_extent_bit(tree, start, failed_start - 1,
996 EXTENT_LOCKED, 1, 0, NULL, mask);
997 return 0;
998 }
999 return 1;
1000}
1001
1002int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
1003 struct extent_state **cached, gfp_t mask)
1004{
1005 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
1006 mask);
1007}
1008
1009int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
1010{
1011 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1012 mask);
1013}
1014
1015/*
1016 * helper function to set both pages and extents in the tree writeback
1017 */
1018static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1019{
1020 unsigned long index = start >> PAGE_CACHE_SHIFT;
1021 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1022 struct page *page;
1023
1024 while (index <= end_index) {
1025 page = find_get_page(tree->mapping, index);
1026 BUG_ON(!page);
1027 set_page_writeback(page);
1028 page_cache_release(page);
1029 index++;
1030 }
1031 return 0;
1032}
1033
1034/* find the first state struct with 'bits' set after 'start', and
1035 * return it. tree->lock must be held. NULL will returned if
1036 * nothing was found after 'start'
1037 */
1038struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
1039 u64 start, int bits)
1040{
1041 struct rb_node *node;
1042 struct extent_state *state;
1043
1044 /*
1045 * this search will find all the extents that end after
1046 * our range starts.
1047 */
1048 node = tree_search(tree, start);
1049 if (!node)
1050 goto out;
1051
1052 while (1) {
1053 state = rb_entry(node, struct extent_state, rb_node);
1054 if (state->end >= start && (state->state & bits))
1055 return state;
1056
1057 node = rb_next(node);
1058 if (!node)
1059 break;
1060 }
1061out:
1062 return NULL;
1063}
1064
1065/*
1066 * find the first offset in the io tree with 'bits' set. zero is
1067 * returned if we find something, and *start_ret and *end_ret are
1068 * set to reflect the state struct that was found.
1069 *
1070 * If nothing was found, 1 is returned, < 0 on error
1071 */
1072int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1073 u64 *start_ret, u64 *end_ret, int bits)
1074{
1075 struct extent_state *state;
1076 int ret = 1;
1077
1078 spin_lock(&tree->lock);
1079 state = find_first_extent_bit_state(tree, start, bits);
1080 if (state) {
1081 *start_ret = state->start;
1082 *end_ret = state->end;
1083 ret = 0;
1084 }
1085 spin_unlock(&tree->lock);
1086 return ret;
1087}
1088
1089/*
1090 * find a contiguous range of bytes in the file marked as delalloc, not
1091 * more than 'max_bytes'. start and end are used to return the range,
1092 *
1093 * 1 is returned if we find something, 0 if nothing was in the tree
1094 */
1095static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1096 u64 *start, u64 *end, u64 max_bytes,
1097 struct extent_state **cached_state)
1098{
1099 struct rb_node *node;
1100 struct extent_state *state;
1101 u64 cur_start = *start;
1102 u64 found = 0;
1103 u64 total_bytes = 0;
1104
1105 spin_lock(&tree->lock);
1106
1107 /*
1108 * this search will find all the extents that end after
1109 * our range starts.
1110 */
1111 node = tree_search(tree, cur_start);
1112 if (!node) {
1113 if (!found)
1114 *end = (u64)-1;
1115 goto out;
1116 }
1117
1118 while (1) {
1119 state = rb_entry(node, struct extent_state, rb_node);
1120 if (found && (state->start != cur_start ||
1121 (state->state & EXTENT_BOUNDARY))) {
1122 goto out;
1123 }
1124 if (!(state->state & EXTENT_DELALLOC)) {
1125 if (!found)
1126 *end = state->end;
1127 goto out;
1128 }
1129 if (!found) {
1130 *start = state->start;
1131 *cached_state = state;
1132 atomic_inc(&state->refs);
1133 }
1134 found++;
1135 *end = state->end;
1136 cur_start = state->end + 1;
1137 node = rb_next(node);
1138 if (!node)
1139 break;
1140 total_bytes += state->end - state->start + 1;
1141 if (total_bytes >= max_bytes)
1142 break;
1143 }
1144out:
1145 spin_unlock(&tree->lock);
1146 return found;
1147}
1148
1149static noinline int __unlock_for_delalloc(struct inode *inode,
1150 struct page *locked_page,
1151 u64 start, u64 end)
1152{
1153 int ret;
1154 struct page *pages[16];
1155 unsigned long index = start >> PAGE_CACHE_SHIFT;
1156 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1157 unsigned long nr_pages = end_index - index + 1;
1158 int i;
1159
1160 if (index == locked_page->index && end_index == index)
1161 return 0;
1162
1163 while (nr_pages > 0) {
1164 ret = find_get_pages_contig(inode->i_mapping, index,
1165 min_t(unsigned long, nr_pages,
1166 ARRAY_SIZE(pages)), pages);
1167 for (i = 0; i < ret; i++) {
1168 if (pages[i] != locked_page)
1169 unlock_page(pages[i]);
1170 page_cache_release(pages[i]);
1171 }
1172 nr_pages -= ret;
1173 index += ret;
1174 cond_resched();
1175 }
1176 return 0;
1177}
1178
1179static noinline int lock_delalloc_pages(struct inode *inode,
1180 struct page *locked_page,
1181 u64 delalloc_start,
1182 u64 delalloc_end)
1183{
1184 unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
1185 unsigned long start_index = index;
1186 unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
1187 unsigned long pages_locked = 0;
1188 struct page *pages[16];
1189 unsigned long nrpages;
1190 int ret;
1191 int i;
1192
1193 /* the caller is responsible for locking the start index */
1194 if (index == locked_page->index && index == end_index)
1195 return 0;
1196
1197 /* skip the page at the start index */
1198 nrpages = end_index - index + 1;
1199 while (nrpages > 0) {
1200 ret = find_get_pages_contig(inode->i_mapping, index,
1201 min_t(unsigned long,
1202 nrpages, ARRAY_SIZE(pages)), pages);
1203 if (ret == 0) {
1204 ret = -EAGAIN;
1205 goto done;
1206 }
1207 /* now we have an array of pages, lock them all */
1208 for (i = 0; i < ret; i++) {
1209 /*
1210 * the caller is taking responsibility for
1211 * locked_page
1212 */
1213 if (pages[i] != locked_page) {
1214 lock_page(pages[i]);
1215 if (!PageDirty(pages[i]) ||
1216 pages[i]->mapping != inode->i_mapping) {
1217 ret = -EAGAIN;
1218 unlock_page(pages[i]);
1219 page_cache_release(pages[i]);
1220 goto done;
1221 }
1222 }
1223 page_cache_release(pages[i]);
1224 pages_locked++;
1225 }
1226 nrpages -= ret;
1227 index += ret;
1228 cond_resched();
1229 }
1230 ret = 0;
1231done:
1232 if (ret && pages_locked) {
1233 __unlock_for_delalloc(inode, locked_page,
1234 delalloc_start,
1235 ((u64)(start_index + pages_locked - 1)) <<
1236 PAGE_CACHE_SHIFT);
1237 }
1238 return ret;
1239}
1240
1241/*
1242 * find a contiguous range of bytes in the file marked as delalloc, not
1243 * more than 'max_bytes'. start and end are used to return the range,
1244 *
1245 * 1 is returned if we find something, 0 if nothing was in the tree
1246 */
1247static noinline u64 find_lock_delalloc_range(struct inode *inode,
1248 struct extent_io_tree *tree,
1249 struct page *locked_page,
1250 u64 *start, u64 *end,
1251 u64 max_bytes)
1252{
1253 u64 delalloc_start;
1254 u64 delalloc_end;
1255 u64 found;
1256 struct extent_state *cached_state = NULL;
1257 int ret;
1258 int loops = 0;
1259
1260again:
1261 /* step one, find a bunch of delalloc bytes starting at start */
1262 delalloc_start = *start;
1263 delalloc_end = 0;
1264 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1265 max_bytes, &cached_state);
1266 if (!found || delalloc_end <= *start) {
1267 *start = delalloc_start;
1268 *end = delalloc_end;
1269 free_extent_state(cached_state);
1270 return found;
1271 }
1272
1273 /*
1274 * start comes from the offset of locked_page. We have to lock
1275 * pages in order, so we can't process delalloc bytes before
1276 * locked_page
1277 */
1278 if (delalloc_start < *start)
1279 delalloc_start = *start;
1280
1281 /*
1282 * make sure to limit the number of pages we try to lock down
1283 * if we're looping.
1284 */
1285 if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1286 delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
1287
1288 /* step two, lock all the pages after the page that has start */
1289 ret = lock_delalloc_pages(inode, locked_page,
1290 delalloc_start, delalloc_end);
1291 if (ret == -EAGAIN) {
1292 /* some of the pages are gone, lets avoid looping by
1293 * shortening the size of the delalloc range we're searching
1294 */
1295 free_extent_state(cached_state);
1296 if (!loops) {
1297 unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
1298 max_bytes = PAGE_CACHE_SIZE - offset;
1299 loops = 1;
1300 goto again;
1301 } else {
1302 found = 0;
1303 goto out_failed;
1304 }
1305 }
1306 BUG_ON(ret);
1307
1308 /* step three, lock the state bits for the whole range */
1309 lock_extent_bits(tree, delalloc_start, delalloc_end,
1310 0, &cached_state, GFP_NOFS);
1311
1312 /* then test to make sure it is all still delalloc */
1313 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1314 EXTENT_DELALLOC, 1, cached_state);
1315 if (!ret) {
1316 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1317 &cached_state, GFP_NOFS);
1318 __unlock_for_delalloc(inode, locked_page,
1319 delalloc_start, delalloc_end);
1320 cond_resched();
1321 goto again;
1322 }
1323 free_extent_state(cached_state);
1324 *start = delalloc_start;
1325 *end = delalloc_end;
1326out_failed:
1327 return found;
1328}
1329
1330int extent_clear_unlock_delalloc(struct inode *inode,
1331 struct extent_io_tree *tree,
1332 u64 start, u64 end, struct page *locked_page,
1333 unsigned long op)
1334{
1335 int ret;
1336 struct page *pages[16];
1337 unsigned long index = start >> PAGE_CACHE_SHIFT;
1338 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1339 unsigned long nr_pages = end_index - index + 1;
1340 int i;
1341 int clear_bits = 0;
1342
1343 if (op & EXTENT_CLEAR_UNLOCK)
1344 clear_bits |= EXTENT_LOCKED;
1345 if (op & EXTENT_CLEAR_DIRTY)
1346 clear_bits |= EXTENT_DIRTY;
1347
1348 if (op & EXTENT_CLEAR_DELALLOC)
1349 clear_bits |= EXTENT_DELALLOC;
1350
1351 clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1352 if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
1353 EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
1354 EXTENT_SET_PRIVATE2)))
1355 return 0;
1356
1357 while (nr_pages > 0) {
1358 ret = find_get_pages_contig(inode->i_mapping, index,
1359 min_t(unsigned long,
1360 nr_pages, ARRAY_SIZE(pages)), pages);
1361 for (i = 0; i < ret; i++) {
1362
1363 if (op & EXTENT_SET_PRIVATE2)
1364 SetPagePrivate2(pages[i]);
1365
1366 if (pages[i] == locked_page) {
1367 page_cache_release(pages[i]);
1368 continue;
1369 }
1370 if (op & EXTENT_CLEAR_DIRTY)
1371 clear_page_dirty_for_io(pages[i]);
1372 if (op & EXTENT_SET_WRITEBACK)
1373 set_page_writeback(pages[i]);
1374 if (op & EXTENT_END_WRITEBACK)
1375 end_page_writeback(pages[i]);
1376 if (op & EXTENT_CLEAR_UNLOCK_PAGE)
1377 unlock_page(pages[i]);
1378 page_cache_release(pages[i]);
1379 }
1380 nr_pages -= ret;
1381 index += ret;
1382 cond_resched();
1383 }
1384 return 0;
1385}
1386
1387/*
1388 * count the number of bytes in the tree that have a given bit(s)
1389 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1390 * cached. The total number found is returned.
1391 */
1392u64 count_range_bits(struct extent_io_tree *tree,
1393 u64 *start, u64 search_end, u64 max_bytes,
1394 unsigned long bits, int contig)
1395{
1396 struct rb_node *node;
1397 struct extent_state *state;
1398 u64 cur_start = *start;
1399 u64 total_bytes = 0;
1400 u64 last = 0;
1401 int found = 0;
1402
1403 if (search_end <= cur_start) {
1404 WARN_ON(1);
1405 return 0;
1406 }
1407
1408 spin_lock(&tree->lock);
1409 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1410 total_bytes = tree->dirty_bytes;
1411 goto out;
1412 }
1413 /*
1414 * this search will find all the extents that end after
1415 * our range starts.
1416 */
1417 node = tree_search(tree, cur_start);
1418 if (!node)
1419 goto out;
1420
1421 while (1) {
1422 state = rb_entry(node, struct extent_state, rb_node);
1423 if (state->start > search_end)
1424 break;
1425 if (contig && found && state->start > last + 1)
1426 break;
1427 if (state->end >= cur_start && (state->state & bits) == bits) {
1428 total_bytes += min(search_end, state->end) + 1 -
1429 max(cur_start, state->start);
1430 if (total_bytes >= max_bytes)
1431 break;
1432 if (!found) {
1433 *start = max(cur_start, state->start);
1434 found = 1;
1435 }
1436 last = state->end;
1437 } else if (contig && found) {
1438 break;
1439 }
1440 node = rb_next(node);
1441 if (!node)
1442 break;
1443 }
1444out:
1445 spin_unlock(&tree->lock);
1446 return total_bytes;
1447}
1448
1449/*
1450 * set the private field for a given byte offset in the tree. If there isn't
1451 * an extent_state there already, this does nothing.
1452 */
1453int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1454{
1455 struct rb_node *node;
1456 struct extent_state *state;
1457 int ret = 0;
1458
1459 spin_lock(&tree->lock);
1460 /*
1461 * this search will find all the extents that end after
1462 * our range starts.
1463 */
1464 node = tree_search(tree, start);
1465 if (!node) {
1466 ret = -ENOENT;
1467 goto out;
1468 }
1469 state = rb_entry(node, struct extent_state, rb_node);
1470 if (state->start != start) {
1471 ret = -ENOENT;
1472 goto out;
1473 }
1474 state->private = private;
1475out:
1476 spin_unlock(&tree->lock);
1477 return ret;
1478}
1479
1480int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1481{
1482 struct rb_node *node;
1483 struct extent_state *state;
1484 int ret = 0;
1485
1486 spin_lock(&tree->lock);
1487 /*
1488 * this search will find all the extents that end after
1489 * our range starts.
1490 */
1491 node = tree_search(tree, start);
1492 if (!node) {
1493 ret = -ENOENT;
1494 goto out;
1495 }
1496 state = rb_entry(node, struct extent_state, rb_node);
1497 if (state->start != start) {
1498 ret = -ENOENT;
1499 goto out;
1500 }
1501 *private = state->private;
1502out:
1503 spin_unlock(&tree->lock);
1504 return ret;
1505}
1506
1507/*
1508 * searches a range in the state tree for a given mask.
1509 * If 'filled' == 1, this returns 1 only if every extent in the tree
1510 * has the bits set. Otherwise, 1 is returned if any bit in the
1511 * range is found set.
1512 */
1513int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1514 int bits, int filled, struct extent_state *cached)
1515{
1516 struct extent_state *state = NULL;
1517 struct rb_node *node;
1518 int bitset = 0;
1519
1520 spin_lock(&tree->lock);
1521 if (cached && cached->tree && cached->start <= start &&
1522 cached->end > start)
1523 node = &cached->rb_node;
1524 else
1525 node = tree_search(tree, start);
1526 while (node && start <= end) {
1527 state = rb_entry(node, struct extent_state, rb_node);
1528
1529 if (filled && state->start > start) {
1530 bitset = 0;
1531 break;
1532 }
1533
1534 if (state->start > end)
1535 break;
1536
1537 if (state->state & bits) {
1538 bitset = 1;
1539 if (!filled)
1540 break;
1541 } else if (filled) {
1542 bitset = 0;
1543 break;
1544 }
1545
1546 if (state->end == (u64)-1)
1547 break;
1548
1549 start = state->end + 1;
1550 if (start > end)
1551 break;
1552 node = rb_next(node);
1553 if (!node) {
1554 if (filled)
1555 bitset = 0;
1556 break;
1557 }
1558 }
1559 spin_unlock(&tree->lock);
1560 return bitset;
1561}
1562
1563/*
1564 * helper function to set a given page up to date if all the
1565 * extents in the tree for that page are up to date
1566 */
1567static int check_page_uptodate(struct extent_io_tree *tree,
1568 struct page *page)
1569{
1570 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1571 u64 end = start + PAGE_CACHE_SIZE - 1;
1572 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1573 SetPageUptodate(page);
1574 return 0;
1575}
1576
1577/*
1578 * helper function to unlock a page if all the extents in the tree
1579 * for that page are unlocked
1580 */
1581static int check_page_locked(struct extent_io_tree *tree,
1582 struct page *page)
1583{
1584 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1585 u64 end = start + PAGE_CACHE_SIZE - 1;
1586 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
1587 unlock_page(page);
1588 return 0;
1589}
1590
1591/*
1592 * helper function to end page writeback if all the extents
1593 * in the tree for that page are done with writeback
1594 */
1595static int check_page_writeback(struct extent_io_tree *tree,
1596 struct page *page)
1597{
1598 end_page_writeback(page);
1599 return 0;
1600}
1601
1602/* lots and lots of room for performance fixes in the end_bio funcs */
1603
1604/*
1605 * after a writepage IO is done, we need to:
1606 * clear the uptodate bits on error
1607 * clear the writeback bits in the extent tree for this IO
1608 * end_page_writeback if the page has no more pending IO
1609 *
1610 * Scheduling is not allowed, so the extent state tree is expected
1611 * to have one and only one object corresponding to this IO.
1612 */
1613static void end_bio_extent_writepage(struct bio *bio, int err)
1614{
1615 int uptodate = err == 0;
1616 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1617 struct extent_io_tree *tree;
1618 u64 start;
1619 u64 end;
1620 int whole_page;
1621 int ret;
1622
1623 do {
1624 struct page *page = bvec->bv_page;
1625 tree = &BTRFS_I(page->mapping->host)->io_tree;
1626
1627 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1628 bvec->bv_offset;
1629 end = start + bvec->bv_len - 1;
1630
1631 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1632 whole_page = 1;
1633 else
1634 whole_page = 0;
1635
1636 if (--bvec >= bio->bi_io_vec)
1637 prefetchw(&bvec->bv_page->flags);
1638 if (tree->ops && tree->ops->writepage_end_io_hook) {
1639 ret = tree->ops->writepage_end_io_hook(page, start,
1640 end, NULL, uptodate);
1641 if (ret)
1642 uptodate = 0;
1643 }
1644
1645 if (!uptodate && tree->ops &&
1646 tree->ops->writepage_io_failed_hook) {
1647 ret = tree->ops->writepage_io_failed_hook(bio, page,
1648 start, end, NULL);
1649 if (ret == 0) {
1650 uptodate = (err == 0);
1651 continue;
1652 }
1653 }
1654
1655 if (!uptodate) {
1656 clear_extent_uptodate(tree, start, end, NULL, GFP_NOFS);
1657 ClearPageUptodate(page);
1658 SetPageError(page);
1659 }
1660
1661 if (whole_page)
1662 end_page_writeback(page);
1663 else
1664 check_page_writeback(tree, page);
1665 } while (bvec >= bio->bi_io_vec);
1666
1667 bio_put(bio);
1668}
1669
1670/*
1671 * after a readpage IO is done, we need to:
1672 * clear the uptodate bits on error
1673 * set the uptodate bits if things worked
1674 * set the page up to date if all extents in the tree are uptodate
1675 * clear the lock bit in the extent tree
1676 * unlock the page if there are no other extents locked for it
1677 *
1678 * Scheduling is not allowed, so the extent state tree is expected
1679 * to have one and only one object corresponding to this IO.
1680 */
1681static void end_bio_extent_readpage(struct bio *bio, int err)
1682{
1683 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1684 struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
1685 struct bio_vec *bvec = bio->bi_io_vec;
1686 struct extent_io_tree *tree;
1687 u64 start;
1688 u64 end;
1689 int whole_page;
1690 int ret;
1691
1692 if (err)
1693 uptodate = 0;
1694
1695 do {
1696 struct page *page = bvec->bv_page;
1697 struct extent_state *cached = NULL;
1698 struct extent_state *state;
1699
1700 tree = &BTRFS_I(page->mapping->host)->io_tree;
1701
1702 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1703 bvec->bv_offset;
1704 end = start + bvec->bv_len - 1;
1705
1706 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1707 whole_page = 1;
1708 else
1709 whole_page = 0;
1710
1711 if (++bvec <= bvec_end)
1712 prefetchw(&bvec->bv_page->flags);
1713
1714 spin_lock(&tree->lock);
1715 state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
1716 if (state && state->start == start) {
1717 /*
1718 * take a reference on the state, unlock will drop
1719 * the ref
1720 */
1721 cache_state(state, &cached);
1722 }
1723 spin_unlock(&tree->lock);
1724
1725 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1726 ret = tree->ops->readpage_end_io_hook(page, start, end,
1727 state);
1728 if (ret)
1729 uptodate = 0;
1730 }
1731 if (!uptodate && tree->ops &&
1732 tree->ops->readpage_io_failed_hook) {
1733 ret = tree->ops->readpage_io_failed_hook(bio, page,
1734 start, end, NULL);
1735 if (ret == 0) {
1736 uptodate =
1737 test_bit(BIO_UPTODATE, &bio->bi_flags);
1738 if (err)
1739 uptodate = 0;
1740 uncache_state(&cached);
1741 continue;
1742 }
1743 }
1744
1745 if (uptodate) {
1746 set_extent_uptodate(tree, start, end, &cached,
1747 GFP_ATOMIC);
1748 }
1749 unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
1750
1751 if (whole_page) {
1752 if (uptodate) {
1753 SetPageUptodate(page);
1754 } else {
1755 ClearPageUptodate(page);
1756 SetPageError(page);
1757 }
1758 unlock_page(page);
1759 } else {
1760 if (uptodate) {
1761 check_page_uptodate(tree, page);
1762 } else {
1763 ClearPageUptodate(page);
1764 SetPageError(page);
1765 }
1766 check_page_locked(tree, page);
1767 }
1768 } while (bvec <= bvec_end);
1769
1770 bio_put(bio);
1771}
1772
1773struct bio *
1774btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
1775 gfp_t gfp_flags)
1776{
1777 struct bio *bio;
1778
1779 bio = bio_alloc(gfp_flags, nr_vecs);
1780
1781 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
1782 while (!bio && (nr_vecs /= 2))
1783 bio = bio_alloc(gfp_flags, nr_vecs);
1784 }
1785
1786 if (bio) {
1787 bio->bi_size = 0;
1788 bio->bi_bdev = bdev;
1789 bio->bi_sector = first_sector;
1790 }
1791 return bio;
1792}
1793
1794static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
1795 unsigned long bio_flags)
1796{
1797 int ret = 0;
1798 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1799 struct page *page = bvec->bv_page;
1800 struct extent_io_tree *tree = bio->bi_private;
1801 u64 start;
1802
1803 start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1804
1805 bio->bi_private = NULL;
1806
1807 bio_get(bio);
1808
1809 if (tree->ops && tree->ops->submit_bio_hook)
1810 ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1811 mirror_num, bio_flags, start);
1812 else
1813 submit_bio(rw, bio);
1814 if (bio_flagged(bio, BIO_EOPNOTSUPP))
1815 ret = -EOPNOTSUPP;
1816 bio_put(bio);
1817 return ret;
1818}
1819
1820static int submit_extent_page(int rw, struct extent_io_tree *tree,
1821 struct page *page, sector_t sector,
1822 size_t size, unsigned long offset,
1823 struct block_device *bdev,
1824 struct bio **bio_ret,
1825 unsigned long max_pages,
1826 bio_end_io_t end_io_func,
1827 int mirror_num,
1828 unsigned long prev_bio_flags,
1829 unsigned long bio_flags)
1830{
1831 int ret = 0;
1832 struct bio *bio;
1833 int nr;
1834 int contig = 0;
1835 int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
1836 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
1837 size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
1838
1839 if (bio_ret && *bio_ret) {
1840 bio = *bio_ret;
1841 if (old_compressed)
1842 contig = bio->bi_sector == sector;
1843 else
1844 contig = bio->bi_sector + (bio->bi_size >> 9) ==
1845 sector;
1846
1847 if (prev_bio_flags != bio_flags || !contig ||
1848 (tree->ops && tree->ops->merge_bio_hook &&
1849 tree->ops->merge_bio_hook(page, offset, page_size, bio,
1850 bio_flags)) ||
1851 bio_add_page(bio, page, page_size, offset) < page_size) {
1852 ret = submit_one_bio(rw, bio, mirror_num,
1853 prev_bio_flags);
1854 bio = NULL;
1855 } else {
1856 return 0;
1857 }
1858 }
1859 if (this_compressed)
1860 nr = BIO_MAX_PAGES;
1861 else
1862 nr = bio_get_nr_vecs(bdev);
1863
1864 bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1865 if (!bio)
1866 return -ENOMEM;
1867
1868 bio_add_page(bio, page, page_size, offset);
1869 bio->bi_end_io = end_io_func;
1870 bio->bi_private = tree;
1871
1872 if (bio_ret)
1873 *bio_ret = bio;
1874 else
1875 ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
1876
1877 return ret;
1878}
1879
1880void set_page_extent_mapped(struct page *page)
1881{
1882 if (!PagePrivate(page)) {
1883 SetPagePrivate(page);
1884 page_cache_get(page);
1885 set_page_private(page, EXTENT_PAGE_PRIVATE);
1886 }
1887}
1888
1889static void set_page_extent_head(struct page *page, unsigned long len)
1890{
1891 WARN_ON(!PagePrivate(page));
1892 set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
1893}
1894
1895/*
1896 * basic readpage implementation. Locked extent state structs are inserted
1897 * into the tree that are removed when the IO is done (by the end_io
1898 * handlers)
1899 */
1900static int __extent_read_full_page(struct extent_io_tree *tree,
1901 struct page *page,
1902 get_extent_t *get_extent,
1903 struct bio **bio, int mirror_num,
1904 unsigned long *bio_flags)
1905{
1906 struct inode *inode = page->mapping->host;
1907 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1908 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1909 u64 end;
1910 u64 cur = start;
1911 u64 extent_offset;
1912 u64 last_byte = i_size_read(inode);
1913 u64 block_start;
1914 u64 cur_end;
1915 sector_t sector;
1916 struct extent_map *em;
1917 struct block_device *bdev;
1918 struct btrfs_ordered_extent *ordered;
1919 int ret;
1920 int nr = 0;
1921 size_t pg_offset = 0;
1922 size_t iosize;
1923 size_t disk_io_size;
1924 size_t blocksize = inode->i_sb->s_blocksize;
1925 unsigned long this_bio_flag = 0;
1926
1927 set_page_extent_mapped(page);
1928
1929 if (!PageUptodate(page)) {
1930 if (cleancache_get_page(page) == 0) {
1931 BUG_ON(blocksize != PAGE_SIZE);
1932 goto out;
1933 }
1934 }
1935
1936 end = page_end;
1937 while (1) {
1938 lock_extent(tree, start, end, GFP_NOFS);
1939 ordered = btrfs_lookup_ordered_extent(inode, start);
1940 if (!ordered)
1941 break;
1942 unlock_extent(tree, start, end, GFP_NOFS);
1943 btrfs_start_ordered_extent(inode, ordered, 1);
1944 btrfs_put_ordered_extent(ordered);
1945 }
1946
1947 if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
1948 char *userpage;
1949 size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
1950
1951 if (zero_offset) {
1952 iosize = PAGE_CACHE_SIZE - zero_offset;
1953 userpage = kmap_atomic(page, KM_USER0);
1954 memset(userpage + zero_offset, 0, iosize);
1955 flush_dcache_page(page);
1956 kunmap_atomic(userpage, KM_USER0);
1957 }
1958 }
1959 while (cur <= end) {
1960 if (cur >= last_byte) {
1961 char *userpage;
1962 struct extent_state *cached = NULL;
1963
1964 iosize = PAGE_CACHE_SIZE - pg_offset;
1965 userpage = kmap_atomic(page, KM_USER0);
1966 memset(userpage + pg_offset, 0, iosize);
1967 flush_dcache_page(page);
1968 kunmap_atomic(userpage, KM_USER0);
1969 set_extent_uptodate(tree, cur, cur + iosize - 1,
1970 &cached, GFP_NOFS);
1971 unlock_extent_cached(tree, cur, cur + iosize - 1,
1972 &cached, GFP_NOFS);
1973 break;
1974 }
1975 em = get_extent(inode, page, pg_offset, cur,
1976 end - cur + 1, 0);
1977 if (IS_ERR_OR_NULL(em)) {
1978 SetPageError(page);
1979 unlock_extent(tree, cur, end, GFP_NOFS);
1980 break;
1981 }
1982 extent_offset = cur - em->start;
1983 BUG_ON(extent_map_end(em) <= cur);
1984 BUG_ON(end < cur);
1985
1986 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1987 this_bio_flag = EXTENT_BIO_COMPRESSED;
1988 extent_set_compress_type(&this_bio_flag,
1989 em->compress_type);
1990 }
1991
1992 iosize = min(extent_map_end(em) - cur, end - cur + 1);
1993 cur_end = min(extent_map_end(em) - 1, end);
1994 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
1995 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
1996 disk_io_size = em->block_len;
1997 sector = em->block_start >> 9;
1998 } else {
1999 sector = (em->block_start + extent_offset) >> 9;
2000 disk_io_size = iosize;
2001 }
2002 bdev = em->bdev;
2003 block_start = em->block_start;
2004 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2005 block_start = EXTENT_MAP_HOLE;
2006 free_extent_map(em);
2007 em = NULL;
2008
2009 /* we've found a hole, just zero and go on */
2010 if (block_start == EXTENT_MAP_HOLE) {
2011 char *userpage;
2012 struct extent_state *cached = NULL;
2013
2014 userpage = kmap_atomic(page, KM_USER0);
2015 memset(userpage + pg_offset, 0, iosize);
2016 flush_dcache_page(page);
2017 kunmap_atomic(userpage, KM_USER0);
2018
2019 set_extent_uptodate(tree, cur, cur + iosize - 1,
2020 &cached, GFP_NOFS);
2021 unlock_extent_cached(tree, cur, cur + iosize - 1,
2022 &cached, GFP_NOFS);
2023 cur = cur + iosize;
2024 pg_offset += iosize;
2025 continue;
2026 }
2027 /* the get_extent function already copied into the page */
2028 if (test_range_bit(tree, cur, cur_end,
2029 EXTENT_UPTODATE, 1, NULL)) {
2030 check_page_uptodate(tree, page);
2031 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2032 cur = cur + iosize;
2033 pg_offset += iosize;
2034 continue;
2035 }
2036 /* we have an inline extent but it didn't get marked up
2037 * to date. Error out
2038 */
2039 if (block_start == EXTENT_MAP_INLINE) {
2040 SetPageError(page);
2041 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2042 cur = cur + iosize;
2043 pg_offset += iosize;
2044 continue;
2045 }
2046
2047 ret = 0;
2048 if (tree->ops && tree->ops->readpage_io_hook) {
2049 ret = tree->ops->readpage_io_hook(page, cur,
2050 cur + iosize - 1);
2051 }
2052 if (!ret) {
2053 unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
2054 pnr -= page->index;
2055 ret = submit_extent_page(READ, tree, page,
2056 sector, disk_io_size, pg_offset,
2057 bdev, bio, pnr,
2058 end_bio_extent_readpage, mirror_num,
2059 *bio_flags,
2060 this_bio_flag);
2061 nr++;
2062 *bio_flags = this_bio_flag;
2063 }
2064 if (ret)
2065 SetPageError(page);
2066 cur = cur + iosize;
2067 pg_offset += iosize;
2068 }
2069out:
2070 if (!nr) {
2071 if (!PageError(page))
2072 SetPageUptodate(page);
2073 unlock_page(page);
2074 }
2075 return 0;
2076}
2077
2078int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
2079 get_extent_t *get_extent)
2080{
2081 struct bio *bio = NULL;
2082 unsigned long bio_flags = 0;
2083 int ret;
2084
2085 ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
2086 &bio_flags);
2087 if (bio)
2088 ret = submit_one_bio(READ, bio, 0, bio_flags);
2089 return ret;
2090}
2091
2092static noinline void update_nr_written(struct page *page,
2093 struct writeback_control *wbc,
2094 unsigned long nr_written)
2095{
2096 wbc->nr_to_write -= nr_written;
2097 if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
2098 wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
2099 page->mapping->writeback_index = page->index + nr_written;
2100}
2101
2102/*
2103 * the writepage semantics are similar to regular writepage. extent
2104 * records are inserted to lock ranges in the tree, and as dirty areas
2105 * are found, they are marked writeback. Then the lock bits are removed
2106 * and the end_io handler clears the writeback ranges
2107 */
2108static int __extent_writepage(struct page *page, struct writeback_control *wbc,
2109 void *data)
2110{
2111 struct inode *inode = page->mapping->host;
2112 struct extent_page_data *epd = data;
2113 struct extent_io_tree *tree = epd->tree;
2114 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2115 u64 delalloc_start;
2116 u64 page_end = start + PAGE_CACHE_SIZE - 1;
2117 u64 end;
2118 u64 cur = start;
2119 u64 extent_offset;
2120 u64 last_byte = i_size_read(inode);
2121 u64 block_start;
2122 u64 iosize;
2123 sector_t sector;
2124 struct extent_state *cached_state = NULL;
2125 struct extent_map *em;
2126 struct block_device *bdev;
2127 int ret;
2128 int nr = 0;
2129 size_t pg_offset = 0;
2130 size_t blocksize;
2131 loff_t i_size = i_size_read(inode);
2132 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2133 u64 nr_delalloc;
2134 u64 delalloc_end;
2135 int page_started;
2136 int compressed;
2137 int write_flags;
2138 unsigned long nr_written = 0;
2139
2140 if (wbc->sync_mode == WB_SYNC_ALL)
2141 write_flags = WRITE_SYNC;
2142 else
2143 write_flags = WRITE;
2144
2145 trace___extent_writepage(page, inode, wbc);
2146
2147 WARN_ON(!PageLocked(page));
2148 pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2149 if (page->index > end_index ||
2150 (page->index == end_index && !pg_offset)) {
2151 page->mapping->a_ops->invalidatepage(page, 0);
2152 unlock_page(page);
2153 return 0;
2154 }
2155
2156 if (page->index == end_index) {
2157 char *userpage;
2158
2159 userpage = kmap_atomic(page, KM_USER0);
2160 memset(userpage + pg_offset, 0,
2161 PAGE_CACHE_SIZE - pg_offset);
2162 kunmap_atomic(userpage, KM_USER0);
2163 flush_dcache_page(page);
2164 }
2165 pg_offset = 0;
2166
2167 set_page_extent_mapped(page);
2168
2169 delalloc_start = start;
2170 delalloc_end = 0;
2171 page_started = 0;
2172 if (!epd->extent_locked) {
2173 u64 delalloc_to_write = 0;
2174 /*
2175 * make sure the wbc mapping index is at least updated
2176 * to this page.
2177 */
2178 update_nr_written(page, wbc, 0);
2179
2180 while (delalloc_end < page_end) {
2181 nr_delalloc = find_lock_delalloc_range(inode, tree,
2182 page,
2183 &delalloc_start,
2184 &delalloc_end,
2185 128 * 1024 * 1024);
2186 if (nr_delalloc == 0) {
2187 delalloc_start = delalloc_end + 1;
2188 continue;
2189 }
2190 tree->ops->fill_delalloc(inode, page, delalloc_start,
2191 delalloc_end, &page_started,
2192 &nr_written);
2193 /*
2194 * delalloc_end is already one less than the total
2195 * length, so we don't subtract one from
2196 * PAGE_CACHE_SIZE
2197 */
2198 delalloc_to_write += (delalloc_end - delalloc_start +
2199 PAGE_CACHE_SIZE) >>
2200 PAGE_CACHE_SHIFT;
2201 delalloc_start = delalloc_end + 1;
2202 }
2203 if (wbc->nr_to_write < delalloc_to_write) {
2204 int thresh = 8192;
2205
2206 if (delalloc_to_write < thresh * 2)
2207 thresh = delalloc_to_write;
2208 wbc->nr_to_write = min_t(u64, delalloc_to_write,
2209 thresh);
2210 }
2211
2212 /* did the fill delalloc function already unlock and start
2213 * the IO?
2214 */
2215 if (page_started) {
2216 ret = 0;
2217 /*
2218 * we've unlocked the page, so we can't update
2219 * the mapping's writeback index, just update
2220 * nr_to_write.
2221 */
2222 wbc->nr_to_write -= nr_written;
2223 goto done_unlocked;
2224 }
2225 }
2226 if (tree->ops && tree->ops->writepage_start_hook) {
2227 ret = tree->ops->writepage_start_hook(page, start,
2228 page_end);
2229 if (ret == -EAGAIN) {
2230 redirty_page_for_writepage(wbc, page);
2231 update_nr_written(page, wbc, nr_written);
2232 unlock_page(page);
2233 ret = 0;
2234 goto done_unlocked;
2235 }
2236 }
2237
2238 /*
2239 * we don't want to touch the inode after unlocking the page,
2240 * so we update the mapping writeback index now
2241 */
2242 update_nr_written(page, wbc, nr_written + 1);
2243
2244 end = page_end;
2245 if (last_byte <= start) {
2246 if (tree->ops && tree->ops->writepage_end_io_hook)
2247 tree->ops->writepage_end_io_hook(page, start,
2248 page_end, NULL, 1);
2249 goto done;
2250 }
2251
2252 blocksize = inode->i_sb->s_blocksize;
2253
2254 while (cur <= end) {
2255 if (cur >= last_byte) {
2256 if (tree->ops && tree->ops->writepage_end_io_hook)
2257 tree->ops->writepage_end_io_hook(page, cur,
2258 page_end, NULL, 1);
2259 break;
2260 }
2261 em = epd->get_extent(inode, page, pg_offset, cur,
2262 end - cur + 1, 1);
2263 if (IS_ERR_OR_NULL(em)) {
2264 SetPageError(page);
2265 break;
2266 }
2267
2268 extent_offset = cur - em->start;
2269 BUG_ON(extent_map_end(em) <= cur);
2270 BUG_ON(end < cur);
2271 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2272 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2273 sector = (em->block_start + extent_offset) >> 9;
2274 bdev = em->bdev;
2275 block_start = em->block_start;
2276 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2277 free_extent_map(em);
2278 em = NULL;
2279
2280 /*
2281 * compressed and inline extents are written through other
2282 * paths in the FS
2283 */
2284 if (compressed || block_start == EXTENT_MAP_HOLE ||
2285 block_start == EXTENT_MAP_INLINE) {
2286 /*
2287 * end_io notification does not happen here for
2288 * compressed extents
2289 */
2290 if (!compressed && tree->ops &&
2291 tree->ops->writepage_end_io_hook)
2292 tree->ops->writepage_end_io_hook(page, cur,
2293 cur + iosize - 1,
2294 NULL, 1);
2295 else if (compressed) {
2296 /* we don't want to end_page_writeback on
2297 * a compressed extent. this happens
2298 * elsewhere
2299 */
2300 nr++;
2301 }
2302
2303 cur += iosize;
2304 pg_offset += iosize;
2305 continue;
2306 }
2307 /* leave this out until we have a page_mkwrite call */
2308 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2309 EXTENT_DIRTY, 0, NULL)) {
2310 cur = cur + iosize;
2311 pg_offset += iosize;
2312 continue;
2313 }
2314
2315 if (tree->ops && tree->ops->writepage_io_hook) {
2316 ret = tree->ops->writepage_io_hook(page, cur,
2317 cur + iosize - 1);
2318 } else {
2319 ret = 0;
2320 }
2321 if (ret) {
2322 SetPageError(page);
2323 } else {
2324 unsigned long max_nr = end_index + 1;
2325
2326 set_range_writeback(tree, cur, cur + iosize - 1);
2327 if (!PageWriteback(page)) {
2328 printk(KERN_ERR "btrfs warning page %lu not "
2329 "writeback, cur %llu end %llu\n",
2330 page->index, (unsigned long long)cur,
2331 (unsigned long long)end);
2332 }
2333
2334 ret = submit_extent_page(write_flags, tree, page,
2335 sector, iosize, pg_offset,
2336 bdev, &epd->bio, max_nr,
2337 end_bio_extent_writepage,
2338 0, 0, 0);
2339 if (ret)
2340 SetPageError(page);
2341 }
2342 cur = cur + iosize;
2343 pg_offset += iosize;
2344 nr++;
2345 }
2346done:
2347 if (nr == 0) {
2348 /* make sure the mapping tag for page dirty gets cleared */
2349 set_page_writeback(page);
2350 end_page_writeback(page);
2351 }
2352 unlock_page(page);
2353
2354done_unlocked:
2355
2356 /* drop our reference on any cached states */
2357 free_extent_state(cached_state);
2358 return 0;
2359}
2360
2361/**
2362 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
2363 * @mapping: address space structure to write
2364 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
2365 * @writepage: function called for each page
2366 * @data: data passed to writepage function
2367 *
2368 * If a page is already under I/O, write_cache_pages() skips it, even
2369 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
2370 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
2371 * and msync() need to guarantee that all the data which was dirty at the time
2372 * the call was made get new I/O started against them. If wbc->sync_mode is
2373 * WB_SYNC_ALL then we were called for data integrity and we must wait for
2374 * existing IO to complete.
2375 */
2376static int extent_write_cache_pages(struct extent_io_tree *tree,
2377 struct address_space *mapping,
2378 struct writeback_control *wbc,
2379 writepage_t writepage, void *data,
2380 void (*flush_fn)(void *))
2381{
2382 int ret = 0;
2383 int done = 0;
2384 int nr_to_write_done = 0;
2385 struct pagevec pvec;
2386 int nr_pages;
2387 pgoff_t index;
2388 pgoff_t end; /* Inclusive */
2389 int scanned = 0;
2390 int tag;
2391
2392 pagevec_init(&pvec, 0);
2393 if (wbc->range_cyclic) {
2394 index = mapping->writeback_index; /* Start from prev offset */
2395 end = -1;
2396 } else {
2397 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2398 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2399 scanned = 1;
2400 }
2401 if (wbc->sync_mode == WB_SYNC_ALL)
2402 tag = PAGECACHE_TAG_TOWRITE;
2403 else
2404 tag = PAGECACHE_TAG_DIRTY;
2405retry:
2406 if (wbc->sync_mode == WB_SYNC_ALL)
2407 tag_pages_for_writeback(mapping, index, end);
2408 while (!done && !nr_to_write_done && (index <= end) &&
2409 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2410 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2411 unsigned i;
2412
2413 scanned = 1;
2414 for (i = 0; i < nr_pages; i++) {
2415 struct page *page = pvec.pages[i];
2416
2417 /*
2418 * At this point we hold neither mapping->tree_lock nor
2419 * lock on the page itself: the page may be truncated or
2420 * invalidated (changing page->mapping to NULL), or even
2421 * swizzled back from swapper_space to tmpfs file
2422 * mapping
2423 */
2424 if (tree->ops && tree->ops->write_cache_pages_lock_hook)
2425 tree->ops->write_cache_pages_lock_hook(page);
2426 else
2427 lock_page(page);
2428
2429 if (unlikely(page->mapping != mapping)) {
2430 unlock_page(page);
2431 continue;
2432 }
2433
2434 if (!wbc->range_cyclic && page->index > end) {
2435 done = 1;
2436 unlock_page(page);
2437 continue;
2438 }
2439
2440 if (wbc->sync_mode != WB_SYNC_NONE) {
2441 if (PageWriteback(page))
2442 flush_fn(data);
2443 wait_on_page_writeback(page);
2444 }
2445
2446 if (PageWriteback(page) ||
2447 !clear_page_dirty_for_io(page)) {
2448 unlock_page(page);
2449 continue;
2450 }
2451
2452 ret = (*writepage)(page, wbc, data);
2453
2454 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
2455 unlock_page(page);
2456 ret = 0;
2457 }
2458 if (ret)
2459 done = 1;
2460
2461 /*
2462 * the filesystem may choose to bump up nr_to_write.
2463 * We have to make sure to honor the new nr_to_write
2464 * at any time
2465 */
2466 nr_to_write_done = wbc->nr_to_write <= 0;
2467 }
2468 pagevec_release(&pvec);
2469 cond_resched();
2470 }
2471 if (!scanned && !done) {
2472 /*
2473 * We hit the last page and there is more work to be done: wrap
2474 * back to the start of the file
2475 */
2476 scanned = 1;
2477 index = 0;
2478 goto retry;
2479 }
2480 return ret;
2481}
2482
2483static void flush_epd_write_bio(struct extent_page_data *epd)
2484{
2485 if (epd->bio) {
2486 if (epd->sync_io)
2487 submit_one_bio(WRITE_SYNC, epd->bio, 0, 0);
2488 else
2489 submit_one_bio(WRITE, epd->bio, 0, 0);
2490 epd->bio = NULL;
2491 }
2492}
2493
2494static noinline void flush_write_bio(void *data)
2495{
2496 struct extent_page_data *epd = data;
2497 flush_epd_write_bio(epd);
2498}
2499
2500int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
2501 get_extent_t *get_extent,
2502 struct writeback_control *wbc)
2503{
2504 int ret;
2505 struct extent_page_data epd = {
2506 .bio = NULL,
2507 .tree = tree,
2508 .get_extent = get_extent,
2509 .extent_locked = 0,
2510 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2511 };
2512
2513 ret = __extent_writepage(page, wbc, &epd);
2514
2515 flush_epd_write_bio(&epd);
2516 return ret;
2517}
2518
2519int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
2520 u64 start, u64 end, get_extent_t *get_extent,
2521 int mode)
2522{
2523 int ret = 0;
2524 struct address_space *mapping = inode->i_mapping;
2525 struct page *page;
2526 unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
2527 PAGE_CACHE_SHIFT;
2528
2529 struct extent_page_data epd = {
2530 .bio = NULL,
2531 .tree = tree,
2532 .get_extent = get_extent,
2533 .extent_locked = 1,
2534 .sync_io = mode == WB_SYNC_ALL,
2535 };
2536 struct writeback_control wbc_writepages = {
2537 .sync_mode = mode,
2538 .nr_to_write = nr_pages * 2,
2539 .range_start = start,
2540 .range_end = end + 1,
2541 };
2542
2543 while (start <= end) {
2544 page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
2545 if (clear_page_dirty_for_io(page))
2546 ret = __extent_writepage(page, &wbc_writepages, &epd);
2547 else {
2548 if (tree->ops && tree->ops->writepage_end_io_hook)
2549 tree->ops->writepage_end_io_hook(page, start,
2550 start + PAGE_CACHE_SIZE - 1,
2551 NULL, 1);
2552 unlock_page(page);
2553 }
2554 page_cache_release(page);
2555 start += PAGE_CACHE_SIZE;
2556 }
2557
2558 flush_epd_write_bio(&epd);
2559 return ret;
2560}
2561
2562int extent_writepages(struct extent_io_tree *tree,
2563 struct address_space *mapping,
2564 get_extent_t *get_extent,
2565 struct writeback_control *wbc)
2566{
2567 int ret = 0;
2568 struct extent_page_data epd = {
2569 .bio = NULL,
2570 .tree = tree,
2571 .get_extent = get_extent,
2572 .extent_locked = 0,
2573 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2574 };
2575
2576 ret = extent_write_cache_pages(tree, mapping, wbc,
2577 __extent_writepage, &epd,
2578 flush_write_bio);
2579 flush_epd_write_bio(&epd);
2580 return ret;
2581}
2582
2583int extent_readpages(struct extent_io_tree *tree,
2584 struct address_space *mapping,
2585 struct list_head *pages, unsigned nr_pages,
2586 get_extent_t get_extent)
2587{
2588 struct bio *bio = NULL;
2589 unsigned page_idx;
2590 unsigned long bio_flags = 0;
2591
2592 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
2593 struct page *page = list_entry(pages->prev, struct page, lru);
2594
2595 prefetchw(&page->flags);
2596 list_del(&page->lru);
2597 if (!add_to_page_cache_lru(page, mapping,
2598 page->index, GFP_NOFS)) {
2599 __extent_read_full_page(tree, page, get_extent,
2600 &bio, 0, &bio_flags);
2601 }
2602 page_cache_release(page);
2603 }
2604 BUG_ON(!list_empty(pages));
2605 if (bio)
2606 submit_one_bio(READ, bio, 0, bio_flags);
2607 return 0;
2608}
2609
2610/*
2611 * basic invalidatepage code, this waits on any locked or writeback
2612 * ranges corresponding to the page, and then deletes any extent state
2613 * records from the tree
2614 */
2615int extent_invalidatepage(struct extent_io_tree *tree,
2616 struct page *page, unsigned long offset)
2617{
2618 struct extent_state *cached_state = NULL;
2619 u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
2620 u64 end = start + PAGE_CACHE_SIZE - 1;
2621 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
2622
2623 start += (offset + blocksize - 1) & ~(blocksize - 1);
2624 if (start > end)
2625 return 0;
2626
2627 lock_extent_bits(tree, start, end, 0, &cached_state, GFP_NOFS);
2628 wait_on_page_writeback(page);
2629 clear_extent_bit(tree, start, end,
2630 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
2631 EXTENT_DO_ACCOUNTING,
2632 1, 1, &cached_state, GFP_NOFS);
2633 return 0;
2634}
2635
2636/*
2637 * a helper for releasepage, this tests for areas of the page that
2638 * are locked or under IO and drops the related state bits if it is safe
2639 * to drop the page.
2640 */
2641int try_release_extent_state(struct extent_map_tree *map,
2642 struct extent_io_tree *tree, struct page *page,
2643 gfp_t mask)
2644{
2645 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2646 u64 end = start + PAGE_CACHE_SIZE - 1;
2647 int ret = 1;
2648
2649 if (test_range_bit(tree, start, end,
2650 EXTENT_IOBITS, 0, NULL))
2651 ret = 0;
2652 else {
2653 if ((mask & GFP_NOFS) == GFP_NOFS)
2654 mask = GFP_NOFS;
2655 /*
2656 * at this point we can safely clear everything except the
2657 * locked bit and the nodatasum bit
2658 */
2659 ret = clear_extent_bit(tree, start, end,
2660 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
2661 0, 0, NULL, mask);
2662
2663 /* if clear_extent_bit failed for enomem reasons,
2664 * we can't allow the release to continue.
2665 */
2666 if (ret < 0)
2667 ret = 0;
2668 else
2669 ret = 1;
2670 }
2671 return ret;
2672}
2673
2674/*
2675 * a helper for releasepage. As long as there are no locked extents
2676 * in the range corresponding to the page, both state records and extent
2677 * map records are removed
2678 */
2679int try_release_extent_mapping(struct extent_map_tree *map,
2680 struct extent_io_tree *tree, struct page *page,
2681 gfp_t mask)
2682{
2683 struct extent_map *em;
2684 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2685 u64 end = start + PAGE_CACHE_SIZE - 1;
2686
2687 if ((mask & __GFP_WAIT) &&
2688 page->mapping->host->i_size > 16 * 1024 * 1024) {
2689 u64 len;
2690 while (start <= end) {
2691 len = end - start + 1;
2692 write_lock(&map->lock);
2693 em = lookup_extent_mapping(map, start, len);
2694 if (IS_ERR_OR_NULL(em)) {
2695 write_unlock(&map->lock);
2696 break;
2697 }
2698 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
2699 em->start != start) {
2700 write_unlock(&map->lock);
2701 free_extent_map(em);
2702 break;
2703 }
2704 if (!test_range_bit(tree, em->start,
2705 extent_map_end(em) - 1,
2706 EXTENT_LOCKED | EXTENT_WRITEBACK,
2707 0, NULL)) {
2708 remove_extent_mapping(map, em);
2709 /* once for the rb tree */
2710 free_extent_map(em);
2711 }
2712 start = extent_map_end(em);
2713 write_unlock(&map->lock);
2714
2715 /* once for us */
2716 free_extent_map(em);
2717 }
2718 }
2719 return try_release_extent_state(map, tree, page, mask);
2720}
2721
2722/*
2723 * helper function for fiemap, which doesn't want to see any holes.
2724 * This maps until we find something past 'last'
2725 */
2726static struct extent_map *get_extent_skip_holes(struct inode *inode,
2727 u64 offset,
2728 u64 last,
2729 get_extent_t *get_extent)
2730{
2731 u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
2732 struct extent_map *em;
2733 u64 len;
2734
2735 if (offset >= last)
2736 return NULL;
2737
2738 while(1) {
2739 len = last - offset;
2740 if (len == 0)
2741 break;
2742 len = (len + sectorsize - 1) & ~(sectorsize - 1);
2743 em = get_extent(inode, NULL, 0, offset, len, 0);
2744 if (IS_ERR_OR_NULL(em))
2745 return em;
2746
2747 /* if this isn't a hole return it */
2748 if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
2749 em->block_start != EXTENT_MAP_HOLE) {
2750 return em;
2751 }
2752
2753 /* this is a hole, advance to the next extent */
2754 offset = extent_map_end(em);
2755 free_extent_map(em);
2756 if (offset >= last)
2757 break;
2758 }
2759 return NULL;
2760}
2761
2762int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
2763 __u64 start, __u64 len, get_extent_t *get_extent)
2764{
2765 int ret = 0;
2766 u64 off = start;
2767 u64 max = start + len;
2768 u32 flags = 0;
2769 u32 found_type;
2770 u64 last;
2771 u64 last_for_get_extent = 0;
2772 u64 disko = 0;
2773 u64 isize = i_size_read(inode);
2774 struct btrfs_key found_key;
2775 struct extent_map *em = NULL;
2776 struct extent_state *cached_state = NULL;
2777 struct btrfs_path *path;
2778 struct btrfs_file_extent_item *item;
2779 int end = 0;
2780 u64 em_start = 0;
2781 u64 em_len = 0;
2782 u64 em_end = 0;
2783 unsigned long emflags;
2784
2785 if (len == 0)
2786 return -EINVAL;
2787
2788 path = btrfs_alloc_path();
2789 if (!path)
2790 return -ENOMEM;
2791 path->leave_spinning = 1;
2792
2793 /*
2794 * lookup the last file extent. We're not using i_size here
2795 * because there might be preallocation past i_size
2796 */
2797 ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
2798 path, btrfs_ino(inode), -1, 0);
2799 if (ret < 0) {
2800 btrfs_free_path(path);
2801 return ret;
2802 }
2803 WARN_ON(!ret);
2804 path->slots[0]--;
2805 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2806 struct btrfs_file_extent_item);
2807 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
2808 found_type = btrfs_key_type(&found_key);
2809
2810 /* No extents, but there might be delalloc bits */
2811 if (found_key.objectid != btrfs_ino(inode) ||
2812 found_type != BTRFS_EXTENT_DATA_KEY) {
2813 /* have to trust i_size as the end */
2814 last = (u64)-1;
2815 last_for_get_extent = isize;
2816 } else {
2817 /*
2818 * remember the start of the last extent. There are a
2819 * bunch of different factors that go into the length of the
2820 * extent, so its much less complex to remember where it started
2821 */
2822 last = found_key.offset;
2823 last_for_get_extent = last + 1;
2824 }
2825 btrfs_free_path(path);
2826
2827 /*
2828 * we might have some extents allocated but more delalloc past those
2829 * extents. so, we trust isize unless the start of the last extent is
2830 * beyond isize
2831 */
2832 if (last < isize) {
2833 last = (u64)-1;
2834 last_for_get_extent = isize;
2835 }
2836
2837 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
2838 &cached_state, GFP_NOFS);
2839
2840 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2841 get_extent);
2842 if (!em)
2843 goto out;
2844 if (IS_ERR(em)) {
2845 ret = PTR_ERR(em);
2846 goto out;
2847 }
2848
2849 while (!end) {
2850 u64 offset_in_extent;
2851
2852 /* break if the extent we found is outside the range */
2853 if (em->start >= max || extent_map_end(em) < off)
2854 break;
2855
2856 /*
2857 * get_extent may return an extent that starts before our
2858 * requested range. We have to make sure the ranges
2859 * we return to fiemap always move forward and don't
2860 * overlap, so adjust the offsets here
2861 */
2862 em_start = max(em->start, off);
2863
2864 /*
2865 * record the offset from the start of the extent
2866 * for adjusting the disk offset below
2867 */
2868 offset_in_extent = em_start - em->start;
2869 em_end = extent_map_end(em);
2870 em_len = em_end - em_start;
2871 emflags = em->flags;
2872 disko = 0;
2873 flags = 0;
2874
2875 /*
2876 * bump off for our next call to get_extent
2877 */
2878 off = extent_map_end(em);
2879 if (off >= max)
2880 end = 1;
2881
2882 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
2883 end = 1;
2884 flags |= FIEMAP_EXTENT_LAST;
2885 } else if (em->block_start == EXTENT_MAP_INLINE) {
2886 flags |= (FIEMAP_EXTENT_DATA_INLINE |
2887 FIEMAP_EXTENT_NOT_ALIGNED);
2888 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
2889 flags |= (FIEMAP_EXTENT_DELALLOC |
2890 FIEMAP_EXTENT_UNKNOWN);
2891 } else {
2892 disko = em->block_start + offset_in_extent;
2893 }
2894 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
2895 flags |= FIEMAP_EXTENT_ENCODED;
2896
2897 free_extent_map(em);
2898 em = NULL;
2899 if ((em_start >= last) || em_len == (u64)-1 ||
2900 (last == (u64)-1 && isize <= em_end)) {
2901 flags |= FIEMAP_EXTENT_LAST;
2902 end = 1;
2903 }
2904
2905 /* now scan forward to see if this is really the last extent. */
2906 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2907 get_extent);
2908 if (IS_ERR(em)) {
2909 ret = PTR_ERR(em);
2910 goto out;
2911 }
2912 if (!em) {
2913 flags |= FIEMAP_EXTENT_LAST;
2914 end = 1;
2915 }
2916 ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
2917 em_len, flags);
2918 if (ret)
2919 goto out_free;
2920 }
2921out_free:
2922 free_extent_map(em);
2923out:
2924 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len,
2925 &cached_state, GFP_NOFS);
2926 return ret;
2927}
2928
2929static inline struct page *extent_buffer_page(struct extent_buffer *eb,
2930 unsigned long i)
2931{
2932 struct page *p;
2933 struct address_space *mapping;
2934
2935 if (i == 0)
2936 return eb->first_page;
2937 i += eb->start >> PAGE_CACHE_SHIFT;
2938 mapping = eb->first_page->mapping;
2939 if (!mapping)
2940 return NULL;
2941
2942 /*
2943 * extent_buffer_page is only called after pinning the page
2944 * by increasing the reference count. So we know the page must
2945 * be in the radix tree.
2946 */
2947 rcu_read_lock();
2948 p = radix_tree_lookup(&mapping->page_tree, i);
2949 rcu_read_unlock();
2950
2951 return p;
2952}
2953
2954static inline unsigned long num_extent_pages(u64 start, u64 len)
2955{
2956 return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
2957 (start >> PAGE_CACHE_SHIFT);
2958}
2959
2960static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
2961 u64 start,
2962 unsigned long len,
2963 gfp_t mask)
2964{
2965 struct extent_buffer *eb = NULL;
2966#if LEAK_DEBUG
2967 unsigned long flags;
2968#endif
2969
2970 eb = kmem_cache_zalloc(extent_buffer_cache, mask);
2971 if (eb == NULL)
2972 return NULL;
2973 eb->start = start;
2974 eb->len = len;
2975 rwlock_init(&eb->lock);
2976 atomic_set(&eb->write_locks, 0);
2977 atomic_set(&eb->read_locks, 0);
2978 atomic_set(&eb->blocking_readers, 0);
2979 atomic_set(&eb->blocking_writers, 0);
2980 atomic_set(&eb->spinning_readers, 0);
2981 atomic_set(&eb->spinning_writers, 0);
2982 init_waitqueue_head(&eb->write_lock_wq);
2983 init_waitqueue_head(&eb->read_lock_wq);
2984
2985#if LEAK_DEBUG
2986 spin_lock_irqsave(&leak_lock, flags);
2987 list_add(&eb->leak_list, &buffers);
2988 spin_unlock_irqrestore(&leak_lock, flags);
2989#endif
2990 atomic_set(&eb->refs, 1);
2991
2992 return eb;
2993}
2994
2995static void __free_extent_buffer(struct extent_buffer *eb)
2996{
2997#if LEAK_DEBUG
2998 unsigned long flags;
2999 spin_lock_irqsave(&leak_lock, flags);
3000 list_del(&eb->leak_list);
3001 spin_unlock_irqrestore(&leak_lock, flags);
3002#endif
3003 kmem_cache_free(extent_buffer_cache, eb);
3004}
3005
3006/*
3007 * Helper for releasing extent buffer page.
3008 */
3009static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
3010 unsigned long start_idx)
3011{
3012 unsigned long index;
3013 struct page *page;
3014
3015 if (!eb->first_page)
3016 return;
3017
3018 index = num_extent_pages(eb->start, eb->len);
3019 if (start_idx >= index)
3020 return;
3021
3022 do {
3023 index--;
3024 page = extent_buffer_page(eb, index);
3025 if (page)
3026 page_cache_release(page);
3027 } while (index != start_idx);
3028}
3029
3030/*
3031 * Helper for releasing the extent buffer.
3032 */
3033static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
3034{
3035 btrfs_release_extent_buffer_page(eb, 0);
3036 __free_extent_buffer(eb);
3037}
3038
3039struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
3040 u64 start, unsigned long len,
3041 struct page *page0)
3042{
3043 unsigned long num_pages = num_extent_pages(start, len);
3044 unsigned long i;
3045 unsigned long index = start >> PAGE_CACHE_SHIFT;
3046 struct extent_buffer *eb;
3047 struct extent_buffer *exists = NULL;
3048 struct page *p;
3049 struct address_space *mapping = tree->mapping;
3050 int uptodate = 1;
3051 int ret;
3052
3053 rcu_read_lock();
3054 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3055 if (eb && atomic_inc_not_zero(&eb->refs)) {
3056 rcu_read_unlock();
3057 mark_page_accessed(eb->first_page);
3058 return eb;
3059 }
3060 rcu_read_unlock();
3061
3062 eb = __alloc_extent_buffer(tree, start, len, GFP_NOFS);
3063 if (!eb)
3064 return NULL;
3065
3066 if (page0) {
3067 eb->first_page = page0;
3068 i = 1;
3069 index++;
3070 page_cache_get(page0);
3071 mark_page_accessed(page0);
3072 set_page_extent_mapped(page0);
3073 set_page_extent_head(page0, len);
3074 uptodate = PageUptodate(page0);
3075 } else {
3076 i = 0;
3077 }
3078 for (; i < num_pages; i++, index++) {
3079 p = find_or_create_page(mapping, index, GFP_NOFS);
3080 if (!p) {
3081 WARN_ON(1);
3082 goto free_eb;
3083 }
3084 set_page_extent_mapped(p);
3085 mark_page_accessed(p);
3086 if (i == 0) {
3087 eb->first_page = p;
3088 set_page_extent_head(p, len);
3089 } else {
3090 set_page_private(p, EXTENT_PAGE_PRIVATE);
3091 }
3092 if (!PageUptodate(p))
3093 uptodate = 0;
3094
3095 /*
3096 * see below about how we avoid a nasty race with release page
3097 * and why we unlock later
3098 */
3099 if (i != 0)
3100 unlock_page(p);
3101 }
3102 if (uptodate)
3103 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3104
3105 ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
3106 if (ret)
3107 goto free_eb;
3108
3109 spin_lock(&tree->buffer_lock);
3110 ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
3111 if (ret == -EEXIST) {
3112 exists = radix_tree_lookup(&tree->buffer,
3113 start >> PAGE_CACHE_SHIFT);
3114 /* add one reference for the caller */
3115 atomic_inc(&exists->refs);
3116 spin_unlock(&tree->buffer_lock);
3117 radix_tree_preload_end();
3118 goto free_eb;
3119 }
3120 /* add one reference for the tree */
3121 atomic_inc(&eb->refs);
3122 spin_unlock(&tree->buffer_lock);
3123 radix_tree_preload_end();
3124
3125 /*
3126 * there is a race where release page may have
3127 * tried to find this extent buffer in the radix
3128 * but failed. It will tell the VM it is safe to
3129 * reclaim the, and it will clear the page private bit.
3130 * We must make sure to set the page private bit properly
3131 * after the extent buffer is in the radix tree so
3132 * it doesn't get lost
3133 */
3134 set_page_extent_mapped(eb->first_page);
3135 set_page_extent_head(eb->first_page, eb->len);
3136 if (!page0)
3137 unlock_page(eb->first_page);
3138 return eb;
3139
3140free_eb:
3141 if (eb->first_page && !page0)
3142 unlock_page(eb->first_page);
3143
3144 if (!atomic_dec_and_test(&eb->refs))
3145 return exists;
3146 btrfs_release_extent_buffer(eb);
3147 return exists;
3148}
3149
3150struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
3151 u64 start, unsigned long len)
3152{
3153 struct extent_buffer *eb;
3154
3155 rcu_read_lock();
3156 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3157 if (eb && atomic_inc_not_zero(&eb->refs)) {
3158 rcu_read_unlock();
3159 mark_page_accessed(eb->first_page);
3160 return eb;
3161 }
3162 rcu_read_unlock();
3163
3164 return NULL;
3165}
3166
3167void free_extent_buffer(struct extent_buffer *eb)
3168{
3169 if (!eb)
3170 return;
3171
3172 if (!atomic_dec_and_test(&eb->refs))
3173 return;
3174
3175 WARN_ON(1);
3176}
3177
3178int clear_extent_buffer_dirty(struct extent_io_tree *tree,
3179 struct extent_buffer *eb)
3180{
3181 unsigned long i;
3182 unsigned long num_pages;
3183 struct page *page;
3184
3185 num_pages = num_extent_pages(eb->start, eb->len);
3186
3187 for (i = 0; i < num_pages; i++) {
3188 page = extent_buffer_page(eb, i);
3189 if (!PageDirty(page))
3190 continue;
3191
3192 lock_page(page);
3193 WARN_ON(!PagePrivate(page));
3194
3195 set_page_extent_mapped(page);
3196 if (i == 0)
3197 set_page_extent_head(page, eb->len);
3198
3199 clear_page_dirty_for_io(page);
3200 spin_lock_irq(&page->mapping->tree_lock);
3201 if (!PageDirty(page)) {
3202 radix_tree_tag_clear(&page->mapping->page_tree,
3203 page_index(page),
3204 PAGECACHE_TAG_DIRTY);
3205 }
3206 spin_unlock_irq(&page->mapping->tree_lock);
3207 unlock_page(page);
3208 }
3209 return 0;
3210}
3211
3212int set_extent_buffer_dirty(struct extent_io_tree *tree,
3213 struct extent_buffer *eb)
3214{
3215 unsigned long i;
3216 unsigned long num_pages;
3217 int was_dirty = 0;
3218
3219 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
3220 num_pages = num_extent_pages(eb->start, eb->len);
3221 for (i = 0; i < num_pages; i++)
3222 __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3223 return was_dirty;
3224}
3225
3226static int __eb_straddles_pages(u64 start, u64 len)
3227{
3228 if (len < PAGE_CACHE_SIZE)
3229 return 1;
3230 if (start & (PAGE_CACHE_SIZE - 1))
3231 return 1;
3232 if ((start + len) & (PAGE_CACHE_SIZE - 1))
3233 return 1;
3234 return 0;
3235}
3236
3237static int eb_straddles_pages(struct extent_buffer *eb)
3238{
3239 return __eb_straddles_pages(eb->start, eb->len);
3240}
3241
3242int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3243 struct extent_buffer *eb,
3244 struct extent_state **cached_state)
3245{
3246 unsigned long i;
3247 struct page *page;
3248 unsigned long num_pages;
3249
3250 num_pages = num_extent_pages(eb->start, eb->len);
3251 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3252
3253 if (eb_straddles_pages(eb)) {
3254 clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3255 cached_state, GFP_NOFS);
3256 }
3257 for (i = 0; i < num_pages; i++) {
3258 page = extent_buffer_page(eb, i);
3259 if (page)
3260 ClearPageUptodate(page);
3261 }
3262 return 0;
3263}
3264
3265int set_extent_buffer_uptodate(struct extent_io_tree *tree,
3266 struct extent_buffer *eb)
3267{
3268 unsigned long i;
3269 struct page *page;
3270 unsigned long num_pages;
3271
3272 num_pages = num_extent_pages(eb->start, eb->len);
3273
3274 if (eb_straddles_pages(eb)) {
3275 set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3276 NULL, GFP_NOFS);
3277 }
3278 for (i = 0; i < num_pages; i++) {
3279 page = extent_buffer_page(eb, i);
3280 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3281 ((i == num_pages - 1) &&
3282 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3283 check_page_uptodate(tree, page);
3284 continue;
3285 }
3286 SetPageUptodate(page);
3287 }
3288 return 0;
3289}
3290
3291int extent_range_uptodate(struct extent_io_tree *tree,
3292 u64 start, u64 end)
3293{
3294 struct page *page;
3295 int ret;
3296 int pg_uptodate = 1;
3297 int uptodate;
3298 unsigned long index;
3299
3300 if (__eb_straddles_pages(start, end - start + 1)) {
3301 ret = test_range_bit(tree, start, end,
3302 EXTENT_UPTODATE, 1, NULL);
3303 if (ret)
3304 return 1;
3305 }
3306 while (start <= end) {
3307 index = start >> PAGE_CACHE_SHIFT;
3308 page = find_get_page(tree->mapping, index);
3309 uptodate = PageUptodate(page);
3310 page_cache_release(page);
3311 if (!uptodate) {
3312 pg_uptodate = 0;
3313 break;
3314 }
3315 start += PAGE_CACHE_SIZE;
3316 }
3317 return pg_uptodate;
3318}
3319
3320int extent_buffer_uptodate(struct extent_io_tree *tree,
3321 struct extent_buffer *eb,
3322 struct extent_state *cached_state)
3323{
3324 int ret = 0;
3325 unsigned long num_pages;
3326 unsigned long i;
3327 struct page *page;
3328 int pg_uptodate = 1;
3329
3330 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3331 return 1;
3332
3333 if (eb_straddles_pages(eb)) {
3334 ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3335 EXTENT_UPTODATE, 1, cached_state);
3336 if (ret)
3337 return ret;
3338 }
3339
3340 num_pages = num_extent_pages(eb->start, eb->len);
3341 for (i = 0; i < num_pages; i++) {
3342 page = extent_buffer_page(eb, i);
3343 if (!PageUptodate(page)) {
3344 pg_uptodate = 0;
3345 break;
3346 }
3347 }
3348 return pg_uptodate;
3349}
3350
3351int read_extent_buffer_pages(struct extent_io_tree *tree,
3352 struct extent_buffer *eb,
3353 u64 start, int wait,
3354 get_extent_t *get_extent, int mirror_num)
3355{
3356 unsigned long i;
3357 unsigned long start_i;
3358 struct page *page;
3359 int err;
3360 int ret = 0;
3361 int locked_pages = 0;
3362 int all_uptodate = 1;
3363 int inc_all_pages = 0;
3364 unsigned long num_pages;
3365 struct bio *bio = NULL;
3366 unsigned long bio_flags = 0;
3367
3368 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3369 return 0;
3370
3371 if (eb_straddles_pages(eb)) {
3372 if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3373 EXTENT_UPTODATE, 1, NULL)) {
3374 return 0;
3375 }
3376 }
3377
3378 if (start) {
3379 WARN_ON(start < eb->start);
3380 start_i = (start >> PAGE_CACHE_SHIFT) -
3381 (eb->start >> PAGE_CACHE_SHIFT);
3382 } else {
3383 start_i = 0;
3384 }
3385
3386 num_pages = num_extent_pages(eb->start, eb->len);
3387 for (i = start_i; i < num_pages; i++) {
3388 page = extent_buffer_page(eb, i);
3389 if (!wait) {
3390 if (!trylock_page(page))
3391 goto unlock_exit;
3392 } else {
3393 lock_page(page);
3394 }
3395 locked_pages++;
3396 if (!PageUptodate(page))
3397 all_uptodate = 0;
3398 }
3399 if (all_uptodate) {
3400 if (start_i == 0)
3401 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3402 goto unlock_exit;
3403 }
3404
3405 for (i = start_i; i < num_pages; i++) {
3406 page = extent_buffer_page(eb, i);
3407
3408 WARN_ON(!PagePrivate(page));
3409
3410 set_page_extent_mapped(page);
3411 if (i == 0)
3412 set_page_extent_head(page, eb->len);
3413
3414 if (inc_all_pages)
3415 page_cache_get(page);
3416 if (!PageUptodate(page)) {
3417 if (start_i == 0)
3418 inc_all_pages = 1;
3419 ClearPageError(page);
3420 err = __extent_read_full_page(tree, page,
3421 get_extent, &bio,
3422 mirror_num, &bio_flags);
3423 if (err)
3424 ret = err;
3425 } else {
3426 unlock_page(page);
3427 }
3428 }
3429
3430 if (bio)
3431 submit_one_bio(READ, bio, mirror_num, bio_flags);
3432
3433 if (ret || !wait)
3434 return ret;
3435
3436 for (i = start_i; i < num_pages; i++) {
3437 page = extent_buffer_page(eb, i);
3438 wait_on_page_locked(page);
3439 if (!PageUptodate(page))
3440 ret = -EIO;
3441 }
3442
3443 if (!ret)
3444 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3445 return ret;
3446
3447unlock_exit:
3448 i = start_i;
3449 while (locked_pages > 0) {
3450 page = extent_buffer_page(eb, i);
3451 i++;
3452 unlock_page(page);
3453 locked_pages--;
3454 }
3455 return ret;
3456}
3457
3458void read_extent_buffer(struct extent_buffer *eb, void *dstv,
3459 unsigned long start,
3460 unsigned long len)
3461{
3462 size_t cur;
3463 size_t offset;
3464 struct page *page;
3465 char *kaddr;
3466 char *dst = (char *)dstv;
3467 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3468 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3469
3470 WARN_ON(start > eb->len);
3471 WARN_ON(start + len > eb->start + eb->len);
3472
3473 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3474
3475 while (len > 0) {
3476 page = extent_buffer_page(eb, i);
3477
3478 cur = min(len, (PAGE_CACHE_SIZE - offset));
3479 kaddr = page_address(page);
3480 memcpy(dst, kaddr + offset, cur);
3481
3482 dst += cur;
3483 len -= cur;
3484 offset = 0;
3485 i++;
3486 }
3487}
3488
3489int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
3490 unsigned long min_len, char **map,
3491 unsigned long *map_start,
3492 unsigned long *map_len)
3493{
3494 size_t offset = start & (PAGE_CACHE_SIZE - 1);
3495 char *kaddr;
3496 struct page *p;
3497 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3498 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3499 unsigned long end_i = (start_offset + start + min_len - 1) >>
3500 PAGE_CACHE_SHIFT;
3501
3502 if (i != end_i)
3503 return -EINVAL;
3504
3505 if (i == 0) {
3506 offset = start_offset;
3507 *map_start = 0;
3508 } else {
3509 offset = 0;
3510 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
3511 }
3512
3513 if (start + min_len > eb->len) {
3514 printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
3515 "wanted %lu %lu\n", (unsigned long long)eb->start,
3516 eb->len, start, min_len);
3517 WARN_ON(1);
3518 return -EINVAL;
3519 }
3520
3521 p = extent_buffer_page(eb, i);
3522 kaddr = page_address(p);
3523 *map = kaddr + offset;
3524 *map_len = PAGE_CACHE_SIZE - offset;
3525 return 0;
3526}
3527
3528int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
3529 unsigned long start,
3530 unsigned long len)
3531{
3532 size_t cur;
3533 size_t offset;
3534 struct page *page;
3535 char *kaddr;
3536 char *ptr = (char *)ptrv;
3537 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3538 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3539 int ret = 0;
3540
3541 WARN_ON(start > eb->len);
3542 WARN_ON(start + len > eb->start + eb->len);
3543
3544 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3545
3546 while (len > 0) {
3547 page = extent_buffer_page(eb, i);
3548
3549 cur = min(len, (PAGE_CACHE_SIZE - offset));
3550
3551 kaddr = page_address(page);
3552 ret = memcmp(ptr, kaddr + offset, cur);
3553 if (ret)
3554 break;
3555
3556 ptr += cur;
3557 len -= cur;
3558 offset = 0;
3559 i++;
3560 }
3561 return ret;
3562}
3563
3564void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
3565 unsigned long start, unsigned long len)
3566{
3567 size_t cur;
3568 size_t offset;
3569 struct page *page;
3570 char *kaddr;
3571 char *src = (char *)srcv;
3572 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3573 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3574
3575 WARN_ON(start > eb->len);
3576 WARN_ON(start + len > eb->start + eb->len);
3577
3578 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3579
3580 while (len > 0) {
3581 page = extent_buffer_page(eb, i);
3582 WARN_ON(!PageUptodate(page));
3583
3584 cur = min(len, PAGE_CACHE_SIZE - offset);
3585 kaddr = page_address(page);
3586 memcpy(kaddr + offset, src, cur);
3587
3588 src += cur;
3589 len -= cur;
3590 offset = 0;
3591 i++;
3592 }
3593}
3594
3595void memset_extent_buffer(struct extent_buffer *eb, char c,
3596 unsigned long start, unsigned long len)
3597{
3598 size_t cur;
3599 size_t offset;
3600 struct page *page;
3601 char *kaddr;
3602 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3603 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3604
3605 WARN_ON(start > eb->len);
3606 WARN_ON(start + len > eb->start + eb->len);
3607
3608 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3609
3610 while (len > 0) {
3611 page = extent_buffer_page(eb, i);
3612 WARN_ON(!PageUptodate(page));
3613
3614 cur = min(len, PAGE_CACHE_SIZE - offset);
3615 kaddr = page_address(page);
3616 memset(kaddr + offset, c, cur);
3617
3618 len -= cur;
3619 offset = 0;
3620 i++;
3621 }
3622}
3623
3624void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
3625 unsigned long dst_offset, unsigned long src_offset,
3626 unsigned long len)
3627{
3628 u64 dst_len = dst->len;
3629 size_t cur;
3630 size_t offset;
3631 struct page *page;
3632 char *kaddr;
3633 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3634 unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3635
3636 WARN_ON(src->len != dst_len);
3637
3638 offset = (start_offset + dst_offset) &
3639 ((unsigned long)PAGE_CACHE_SIZE - 1);
3640
3641 while (len > 0) {
3642 page = extent_buffer_page(dst, i);
3643 WARN_ON(!PageUptodate(page));
3644
3645 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
3646
3647 kaddr = page_address(page);
3648 read_extent_buffer(src, kaddr + offset, src_offset, cur);
3649
3650 src_offset += cur;
3651 len -= cur;
3652 offset = 0;
3653 i++;
3654 }
3655}
3656
3657static void move_pages(struct page *dst_page, struct page *src_page,
3658 unsigned long dst_off, unsigned long src_off,
3659 unsigned long len)
3660{
3661 char *dst_kaddr = page_address(dst_page);
3662 if (dst_page == src_page) {
3663 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
3664 } else {
3665 char *src_kaddr = page_address(src_page);
3666 char *p = dst_kaddr + dst_off + len;
3667 char *s = src_kaddr + src_off + len;
3668
3669 while (len--)
3670 *--p = *--s;
3671 }
3672}
3673
3674static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
3675{
3676 unsigned long distance = (src > dst) ? src - dst : dst - src;
3677 return distance < len;
3678}
3679
3680static void copy_pages(struct page *dst_page, struct page *src_page,
3681 unsigned long dst_off, unsigned long src_off,
3682 unsigned long len)
3683{
3684 char *dst_kaddr = page_address(dst_page);
3685 char *src_kaddr;
3686
3687 if (dst_page != src_page) {
3688 src_kaddr = page_address(src_page);
3689 } else {
3690 src_kaddr = dst_kaddr;
3691 BUG_ON(areas_overlap(src_off, dst_off, len));
3692 }
3693
3694 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
3695}
3696
3697void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3698 unsigned long src_offset, unsigned long len)
3699{
3700 size_t cur;
3701 size_t dst_off_in_page;
3702 size_t src_off_in_page;
3703 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3704 unsigned long dst_i;
3705 unsigned long src_i;
3706
3707 if (src_offset + len > dst->len) {
3708 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3709 "len %lu dst len %lu\n", src_offset, len, dst->len);
3710 BUG_ON(1);
3711 }
3712 if (dst_offset + len > dst->len) {
3713 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3714 "len %lu dst len %lu\n", dst_offset, len, dst->len);
3715 BUG_ON(1);
3716 }
3717
3718 while (len > 0) {
3719 dst_off_in_page = (start_offset + dst_offset) &
3720 ((unsigned long)PAGE_CACHE_SIZE - 1);
3721 src_off_in_page = (start_offset + src_offset) &
3722 ((unsigned long)PAGE_CACHE_SIZE - 1);
3723
3724 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3725 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
3726
3727 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
3728 src_off_in_page));
3729 cur = min_t(unsigned long, cur,
3730 (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
3731
3732 copy_pages(extent_buffer_page(dst, dst_i),
3733 extent_buffer_page(dst, src_i),
3734 dst_off_in_page, src_off_in_page, cur);
3735
3736 src_offset += cur;
3737 dst_offset += cur;
3738 len -= cur;
3739 }
3740}
3741
3742void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3743 unsigned long src_offset, unsigned long len)
3744{
3745 size_t cur;
3746 size_t dst_off_in_page;
3747 size_t src_off_in_page;
3748 unsigned long dst_end = dst_offset + len - 1;
3749 unsigned long src_end = src_offset + len - 1;
3750 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3751 unsigned long dst_i;
3752 unsigned long src_i;
3753
3754 if (src_offset + len > dst->len) {
3755 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3756 "len %lu len %lu\n", src_offset, len, dst->len);
3757 BUG_ON(1);
3758 }
3759 if (dst_offset + len > dst->len) {
3760 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3761 "len %lu len %lu\n", dst_offset, len, dst->len);
3762 BUG_ON(1);
3763 }
3764 if (!areas_overlap(src_offset, dst_offset, len)) {
3765 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
3766 return;
3767 }
3768 while (len > 0) {
3769 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
3770 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
3771
3772 dst_off_in_page = (start_offset + dst_end) &
3773 ((unsigned long)PAGE_CACHE_SIZE - 1);
3774 src_off_in_page = (start_offset + src_end) &
3775 ((unsigned long)PAGE_CACHE_SIZE - 1);
3776
3777 cur = min_t(unsigned long, len, src_off_in_page + 1);
3778 cur = min(cur, dst_off_in_page + 1);
3779 move_pages(extent_buffer_page(dst, dst_i),
3780 extent_buffer_page(dst, src_i),
3781 dst_off_in_page - cur + 1,
3782 src_off_in_page - cur + 1, cur);
3783
3784 dst_end -= cur;
3785 src_end -= cur;
3786 len -= cur;
3787 }
3788}
3789
3790static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
3791{
3792 struct extent_buffer *eb =
3793 container_of(head, struct extent_buffer, rcu_head);
3794
3795 btrfs_release_extent_buffer(eb);
3796}
3797
3798int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
3799{
3800 u64 start = page_offset(page);
3801 struct extent_buffer *eb;
3802 int ret = 1;
3803
3804 spin_lock(&tree->buffer_lock);
3805 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3806 if (!eb) {
3807 spin_unlock(&tree->buffer_lock);
3808 return ret;
3809 }
3810
3811 if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3812 ret = 0;
3813 goto out;
3814 }
3815
3816 /*
3817 * set @eb->refs to 0 if it is already 1, and then release the @eb.
3818 * Or go back.
3819 */
3820 if (atomic_cmpxchg(&eb->refs, 1, 0) != 1) {
3821 ret = 0;
3822 goto out;
3823 }
3824
3825 radix_tree_delete(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3826out:
3827 spin_unlock(&tree->buffer_lock);
3828
3829 /* at this point we can safely release the extent buffer */
3830 if (atomic_read(&eb->refs) == 0)
3831 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
3832 return ret;
3833}