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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
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}
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/spinlock.h>
8#include <linux/blkdev.h>
9#include <linux/swap.h>
10#include <linux/writeback.h>
11#include <linux/pagevec.h>
12#include <linux/prefetch.h>
13#include <linux/cleancache.h>
14#include "extent_io.h"
15#include "extent_map.h"
16#include "ctree.h"
17#include "btrfs_inode.h"
18#include "volumes.h"
19#include "check-integrity.h"
20#include "locking.h"
21#include "rcu-string.h"
22#include "backref.h"
23
24static struct kmem_cache *extent_state_cache;
25static struct kmem_cache *extent_buffer_cache;
26static struct bio_set *btrfs_bioset;
27
28static inline bool extent_state_in_tree(const struct extent_state *state)
29{
30 return !RB_EMPTY_NODE(&state->rb_node);
31}
32
33#ifdef CONFIG_BTRFS_DEBUG
34static LIST_HEAD(buffers);
35static LIST_HEAD(states);
36
37static DEFINE_SPINLOCK(leak_lock);
38
39static inline
40void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
41{
42 unsigned long flags;
43
44 spin_lock_irqsave(&leak_lock, flags);
45 list_add(new, head);
46 spin_unlock_irqrestore(&leak_lock, flags);
47}
48
49static inline
50void btrfs_leak_debug_del(struct list_head *entry)
51{
52 unsigned long flags;
53
54 spin_lock_irqsave(&leak_lock, flags);
55 list_del(entry);
56 spin_unlock_irqrestore(&leak_lock, flags);
57}
58
59static inline
60void btrfs_leak_debug_check(void)
61{
62 struct extent_state *state;
63 struct extent_buffer *eb;
64
65 while (!list_empty(&states)) {
66 state = list_entry(states.next, struct extent_state, leak_list);
67 pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
68 state->start, state->end, state->state,
69 extent_state_in_tree(state),
70 atomic_read(&state->refs));
71 list_del(&state->leak_list);
72 kmem_cache_free(extent_state_cache, state);
73 }
74
75 while (!list_empty(&buffers)) {
76 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
77 printk(KERN_ERR "BTRFS: buffer leak start %llu len %lu "
78 "refs %d\n",
79 eb->start, eb->len, atomic_read(&eb->refs));
80 list_del(&eb->leak_list);
81 kmem_cache_free(extent_buffer_cache, eb);
82 }
83}
84
85#define btrfs_debug_check_extent_io_range(tree, start, end) \
86 __btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
87static inline void __btrfs_debug_check_extent_io_range(const char *caller,
88 struct extent_io_tree *tree, u64 start, u64 end)
89{
90 struct inode *inode;
91 u64 isize;
92
93 if (!tree->mapping)
94 return;
95
96 inode = tree->mapping->host;
97 isize = i_size_read(inode);
98 if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
99 btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
100 "%s: ino %llu isize %llu odd range [%llu,%llu]",
101 caller, btrfs_ino(inode), isize, start, end);
102 }
103}
104#else
105#define btrfs_leak_debug_add(new, head) do {} while (0)
106#define btrfs_leak_debug_del(entry) do {} while (0)
107#define btrfs_leak_debug_check() do {} while (0)
108#define btrfs_debug_check_extent_io_range(c, s, e) do {} while (0)
109#endif
110
111#define BUFFER_LRU_MAX 64
112
113struct tree_entry {
114 u64 start;
115 u64 end;
116 struct rb_node rb_node;
117};
118
119struct extent_page_data {
120 struct bio *bio;
121 struct extent_io_tree *tree;
122 get_extent_t *get_extent;
123 unsigned long bio_flags;
124
125 /* tells writepage not to lock the state bits for this range
126 * it still does the unlocking
127 */
128 unsigned int extent_locked:1;
129
130 /* tells the submit_bio code to use a WRITE_SYNC */
131 unsigned int sync_io:1;
132};
133
134static void add_extent_changeset(struct extent_state *state, unsigned bits,
135 struct extent_changeset *changeset,
136 int set)
137{
138 int ret;
139
140 if (!changeset)
141 return;
142 if (set && (state->state & bits) == bits)
143 return;
144 if (!set && (state->state & bits) == 0)
145 return;
146 changeset->bytes_changed += state->end - state->start + 1;
147 ret = ulist_add(changeset->range_changed, state->start, state->end,
148 GFP_ATOMIC);
149 /* ENOMEM */
150 BUG_ON(ret < 0);
151}
152
153static noinline void flush_write_bio(void *data);
154static inline struct btrfs_fs_info *
155tree_fs_info(struct extent_io_tree *tree)
156{
157 if (!tree->mapping)
158 return NULL;
159 return btrfs_sb(tree->mapping->host->i_sb);
160}
161
162int __init extent_io_init(void)
163{
164 extent_state_cache = kmem_cache_create("btrfs_extent_state",
165 sizeof(struct extent_state), 0,
166 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
167 if (!extent_state_cache)
168 return -ENOMEM;
169
170 extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
171 sizeof(struct extent_buffer), 0,
172 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
173 if (!extent_buffer_cache)
174 goto free_state_cache;
175
176 btrfs_bioset = bioset_create(BIO_POOL_SIZE,
177 offsetof(struct btrfs_io_bio, bio));
178 if (!btrfs_bioset)
179 goto free_buffer_cache;
180
181 if (bioset_integrity_create(btrfs_bioset, BIO_POOL_SIZE))
182 goto free_bioset;
183
184 return 0;
185
186free_bioset:
187 bioset_free(btrfs_bioset);
188 btrfs_bioset = NULL;
189
190free_buffer_cache:
191 kmem_cache_destroy(extent_buffer_cache);
192 extent_buffer_cache = NULL;
193
194free_state_cache:
195 kmem_cache_destroy(extent_state_cache);
196 extent_state_cache = NULL;
197 return -ENOMEM;
198}
199
200void extent_io_exit(void)
201{
202 btrfs_leak_debug_check();
203
204 /*
205 * Make sure all delayed rcu free are flushed before we
206 * destroy caches.
207 */
208 rcu_barrier();
209 kmem_cache_destroy(extent_state_cache);
210 kmem_cache_destroy(extent_buffer_cache);
211 if (btrfs_bioset)
212 bioset_free(btrfs_bioset);
213}
214
215void extent_io_tree_init(struct extent_io_tree *tree,
216 struct address_space *mapping)
217{
218 tree->state = RB_ROOT;
219 tree->ops = NULL;
220 tree->dirty_bytes = 0;
221 spin_lock_init(&tree->lock);
222 tree->mapping = mapping;
223}
224
225static struct extent_state *alloc_extent_state(gfp_t mask)
226{
227 struct extent_state *state;
228
229 state = kmem_cache_alloc(extent_state_cache, mask);
230 if (!state)
231 return state;
232 state->state = 0;
233 state->failrec = NULL;
234 RB_CLEAR_NODE(&state->rb_node);
235 btrfs_leak_debug_add(&state->leak_list, &states);
236 atomic_set(&state->refs, 1);
237 init_waitqueue_head(&state->wq);
238 trace_alloc_extent_state(state, mask, _RET_IP_);
239 return state;
240}
241
242void free_extent_state(struct extent_state *state)
243{
244 if (!state)
245 return;
246 if (atomic_dec_and_test(&state->refs)) {
247 WARN_ON(extent_state_in_tree(state));
248 btrfs_leak_debug_del(&state->leak_list);
249 trace_free_extent_state(state, _RET_IP_);
250 kmem_cache_free(extent_state_cache, state);
251 }
252}
253
254static struct rb_node *tree_insert(struct rb_root *root,
255 struct rb_node *search_start,
256 u64 offset,
257 struct rb_node *node,
258 struct rb_node ***p_in,
259 struct rb_node **parent_in)
260{
261 struct rb_node **p;
262 struct rb_node *parent = NULL;
263 struct tree_entry *entry;
264
265 if (p_in && parent_in) {
266 p = *p_in;
267 parent = *parent_in;
268 goto do_insert;
269 }
270
271 p = search_start ? &search_start : &root->rb_node;
272 while (*p) {
273 parent = *p;
274 entry = rb_entry(parent, struct tree_entry, rb_node);
275
276 if (offset < entry->start)
277 p = &(*p)->rb_left;
278 else if (offset > entry->end)
279 p = &(*p)->rb_right;
280 else
281 return parent;
282 }
283
284do_insert:
285 rb_link_node(node, parent, p);
286 rb_insert_color(node, root);
287 return NULL;
288}
289
290static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
291 struct rb_node **prev_ret,
292 struct rb_node **next_ret,
293 struct rb_node ***p_ret,
294 struct rb_node **parent_ret)
295{
296 struct rb_root *root = &tree->state;
297 struct rb_node **n = &root->rb_node;
298 struct rb_node *prev = NULL;
299 struct rb_node *orig_prev = NULL;
300 struct tree_entry *entry;
301 struct tree_entry *prev_entry = NULL;
302
303 while (*n) {
304 prev = *n;
305 entry = rb_entry(prev, struct tree_entry, rb_node);
306 prev_entry = entry;
307
308 if (offset < entry->start)
309 n = &(*n)->rb_left;
310 else if (offset > entry->end)
311 n = &(*n)->rb_right;
312 else
313 return *n;
314 }
315
316 if (p_ret)
317 *p_ret = n;
318 if (parent_ret)
319 *parent_ret = prev;
320
321 if (prev_ret) {
322 orig_prev = prev;
323 while (prev && offset > prev_entry->end) {
324 prev = rb_next(prev);
325 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
326 }
327 *prev_ret = prev;
328 prev = orig_prev;
329 }
330
331 if (next_ret) {
332 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
333 while (prev && offset < prev_entry->start) {
334 prev = rb_prev(prev);
335 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
336 }
337 *next_ret = prev;
338 }
339 return NULL;
340}
341
342static inline struct rb_node *
343tree_search_for_insert(struct extent_io_tree *tree,
344 u64 offset,
345 struct rb_node ***p_ret,
346 struct rb_node **parent_ret)
347{
348 struct rb_node *prev = NULL;
349 struct rb_node *ret;
350
351 ret = __etree_search(tree, offset, &prev, NULL, p_ret, parent_ret);
352 if (!ret)
353 return prev;
354 return ret;
355}
356
357static inline struct rb_node *tree_search(struct extent_io_tree *tree,
358 u64 offset)
359{
360 return tree_search_for_insert(tree, offset, NULL, NULL);
361}
362
363static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
364 struct extent_state *other)
365{
366 if (tree->ops && tree->ops->merge_extent_hook)
367 tree->ops->merge_extent_hook(tree->mapping->host, new,
368 other);
369}
370
371/*
372 * utility function to look for merge candidates inside a given range.
373 * Any extents with matching state are merged together into a single
374 * extent in the tree. Extents with EXTENT_IO in their state field
375 * are not merged because the end_io handlers need to be able to do
376 * operations on them without sleeping (or doing allocations/splits).
377 *
378 * This should be called with the tree lock held.
379 */
380static void merge_state(struct extent_io_tree *tree,
381 struct extent_state *state)
382{
383 struct extent_state *other;
384 struct rb_node *other_node;
385
386 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
387 return;
388
389 other_node = rb_prev(&state->rb_node);
390 if (other_node) {
391 other = rb_entry(other_node, struct extent_state, rb_node);
392 if (other->end == state->start - 1 &&
393 other->state == state->state) {
394 merge_cb(tree, state, other);
395 state->start = other->start;
396 rb_erase(&other->rb_node, &tree->state);
397 RB_CLEAR_NODE(&other->rb_node);
398 free_extent_state(other);
399 }
400 }
401 other_node = rb_next(&state->rb_node);
402 if (other_node) {
403 other = rb_entry(other_node, struct extent_state, rb_node);
404 if (other->start == state->end + 1 &&
405 other->state == state->state) {
406 merge_cb(tree, state, other);
407 state->end = other->end;
408 rb_erase(&other->rb_node, &tree->state);
409 RB_CLEAR_NODE(&other->rb_node);
410 free_extent_state(other);
411 }
412 }
413}
414
415static void set_state_cb(struct extent_io_tree *tree,
416 struct extent_state *state, unsigned *bits)
417{
418 if (tree->ops && tree->ops->set_bit_hook)
419 tree->ops->set_bit_hook(tree->mapping->host, state, bits);
420}
421
422static void clear_state_cb(struct extent_io_tree *tree,
423 struct extent_state *state, unsigned *bits)
424{
425 if (tree->ops && tree->ops->clear_bit_hook)
426 tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
427}
428
429static void set_state_bits(struct extent_io_tree *tree,
430 struct extent_state *state, unsigned *bits,
431 struct extent_changeset *changeset);
432
433/*
434 * insert an extent_state struct into the tree. 'bits' are set on the
435 * struct before it is inserted.
436 *
437 * This may return -EEXIST if the extent is already there, in which case the
438 * state struct is freed.
439 *
440 * The tree lock is not taken internally. This is a utility function and
441 * probably isn't what you want to call (see set/clear_extent_bit).
442 */
443static int insert_state(struct extent_io_tree *tree,
444 struct extent_state *state, u64 start, u64 end,
445 struct rb_node ***p,
446 struct rb_node **parent,
447 unsigned *bits, struct extent_changeset *changeset)
448{
449 struct rb_node *node;
450
451 if (end < start)
452 WARN(1, KERN_ERR "BTRFS: end < start %llu %llu\n",
453 end, start);
454 state->start = start;
455 state->end = end;
456
457 set_state_bits(tree, state, bits, changeset);
458
459 node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
460 if (node) {
461 struct extent_state *found;
462 found = rb_entry(node, struct extent_state, rb_node);
463 printk(KERN_ERR "BTRFS: found node %llu %llu on insert of "
464 "%llu %llu\n",
465 found->start, found->end, start, end);
466 return -EEXIST;
467 }
468 merge_state(tree, state);
469 return 0;
470}
471
472static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
473 u64 split)
474{
475 if (tree->ops && tree->ops->split_extent_hook)
476 tree->ops->split_extent_hook(tree->mapping->host, orig, split);
477}
478
479/*
480 * split a given extent state struct in two, inserting the preallocated
481 * struct 'prealloc' as the newly created second half. 'split' indicates an
482 * offset inside 'orig' where it should be split.
483 *
484 * Before calling,
485 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
486 * are two extent state structs in the tree:
487 * prealloc: [orig->start, split - 1]
488 * orig: [ split, orig->end ]
489 *
490 * The tree locks are not taken by this function. They need to be held
491 * by the caller.
492 */
493static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
494 struct extent_state *prealloc, u64 split)
495{
496 struct rb_node *node;
497
498 split_cb(tree, orig, split);
499
500 prealloc->start = orig->start;
501 prealloc->end = split - 1;
502 prealloc->state = orig->state;
503 orig->start = split;
504
505 node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
506 &prealloc->rb_node, NULL, NULL);
507 if (node) {
508 free_extent_state(prealloc);
509 return -EEXIST;
510 }
511 return 0;
512}
513
514static struct extent_state *next_state(struct extent_state *state)
515{
516 struct rb_node *next = rb_next(&state->rb_node);
517 if (next)
518 return rb_entry(next, struct extent_state, rb_node);
519 else
520 return NULL;
521}
522
523/*
524 * utility function to clear some bits in an extent state struct.
525 * it will optionally wake up any one waiting on this state (wake == 1).
526 *
527 * If no bits are set on the state struct after clearing things, the
528 * struct is freed and removed from the tree
529 */
530static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
531 struct extent_state *state,
532 unsigned *bits, int wake,
533 struct extent_changeset *changeset)
534{
535 struct extent_state *next;
536 unsigned bits_to_clear = *bits & ~EXTENT_CTLBITS;
537
538 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
539 u64 range = state->end - state->start + 1;
540 WARN_ON(range > tree->dirty_bytes);
541 tree->dirty_bytes -= range;
542 }
543 clear_state_cb(tree, state, bits);
544 add_extent_changeset(state, bits_to_clear, changeset, 0);
545 state->state &= ~bits_to_clear;
546 if (wake)
547 wake_up(&state->wq);
548 if (state->state == 0) {
549 next = next_state(state);
550 if (extent_state_in_tree(state)) {
551 rb_erase(&state->rb_node, &tree->state);
552 RB_CLEAR_NODE(&state->rb_node);
553 free_extent_state(state);
554 } else {
555 WARN_ON(1);
556 }
557 } else {
558 merge_state(tree, state);
559 next = next_state(state);
560 }
561 return next;
562}
563
564static struct extent_state *
565alloc_extent_state_atomic(struct extent_state *prealloc)
566{
567 if (!prealloc)
568 prealloc = alloc_extent_state(GFP_ATOMIC);
569
570 return prealloc;
571}
572
573static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
574{
575 btrfs_panic(tree_fs_info(tree), err, "Locking error: "
576 "Extent tree was modified by another "
577 "thread while locked.");
578}
579
580/*
581 * clear some bits on a range in the tree. This may require splitting
582 * or inserting elements in the tree, so the gfp mask is used to
583 * indicate which allocations or sleeping are allowed.
584 *
585 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
586 * the given range from the tree regardless of state (ie for truncate).
587 *
588 * the range [start, end] is inclusive.
589 *
590 * This takes the tree lock, and returns 0 on success and < 0 on error.
591 */
592static int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
593 unsigned bits, int wake, int delete,
594 struct extent_state **cached_state,
595 gfp_t mask, struct extent_changeset *changeset)
596{
597 struct extent_state *state;
598 struct extent_state *cached;
599 struct extent_state *prealloc = NULL;
600 struct rb_node *node;
601 u64 last_end;
602 int err;
603 int clear = 0;
604
605 btrfs_debug_check_extent_io_range(tree, start, end);
606
607 if (bits & EXTENT_DELALLOC)
608 bits |= EXTENT_NORESERVE;
609
610 if (delete)
611 bits |= ~EXTENT_CTLBITS;
612 bits |= EXTENT_FIRST_DELALLOC;
613
614 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
615 clear = 1;
616again:
617 if (!prealloc && gfpflags_allow_blocking(mask)) {
618 /*
619 * Don't care for allocation failure here because we might end
620 * up not needing the pre-allocated extent state at all, which
621 * is the case if we only have in the tree extent states that
622 * cover our input range and don't cover too any other range.
623 * If we end up needing a new extent state we allocate it later.
624 */
625 prealloc = alloc_extent_state(mask);
626 }
627
628 spin_lock(&tree->lock);
629 if (cached_state) {
630 cached = *cached_state;
631
632 if (clear) {
633 *cached_state = NULL;
634 cached_state = NULL;
635 }
636
637 if (cached && extent_state_in_tree(cached) &&
638 cached->start <= start && cached->end > start) {
639 if (clear)
640 atomic_dec(&cached->refs);
641 state = cached;
642 goto hit_next;
643 }
644 if (clear)
645 free_extent_state(cached);
646 }
647 /*
648 * this search will find the extents that end after
649 * our range starts
650 */
651 node = tree_search(tree, start);
652 if (!node)
653 goto out;
654 state = rb_entry(node, struct extent_state, rb_node);
655hit_next:
656 if (state->start > end)
657 goto out;
658 WARN_ON(state->end < start);
659 last_end = state->end;
660
661 /* the state doesn't have the wanted bits, go ahead */
662 if (!(state->state & bits)) {
663 state = next_state(state);
664 goto next;
665 }
666
667 /*
668 * | ---- desired range ---- |
669 * | state | or
670 * | ------------- state -------------- |
671 *
672 * We need to split the extent we found, and may flip
673 * bits on second half.
674 *
675 * If the extent we found extends past our range, we
676 * just split and search again. It'll get split again
677 * the next time though.
678 *
679 * If the extent we found is inside our range, we clear
680 * the desired bit on it.
681 */
682
683 if (state->start < start) {
684 prealloc = alloc_extent_state_atomic(prealloc);
685 BUG_ON(!prealloc);
686 err = split_state(tree, state, prealloc, start);
687 if (err)
688 extent_io_tree_panic(tree, err);
689
690 prealloc = NULL;
691 if (err)
692 goto out;
693 if (state->end <= end) {
694 state = clear_state_bit(tree, state, &bits, wake,
695 changeset);
696 goto next;
697 }
698 goto search_again;
699 }
700 /*
701 * | ---- desired range ---- |
702 * | state |
703 * We need to split the extent, and clear the bit
704 * on the first half
705 */
706 if (state->start <= end && state->end > end) {
707 prealloc = alloc_extent_state_atomic(prealloc);
708 BUG_ON(!prealloc);
709 err = split_state(tree, state, prealloc, end + 1);
710 if (err)
711 extent_io_tree_panic(tree, err);
712
713 if (wake)
714 wake_up(&state->wq);
715
716 clear_state_bit(tree, prealloc, &bits, wake, changeset);
717
718 prealloc = NULL;
719 goto out;
720 }
721
722 state = clear_state_bit(tree, state, &bits, wake, changeset);
723next:
724 if (last_end == (u64)-1)
725 goto out;
726 start = last_end + 1;
727 if (start <= end && state && !need_resched())
728 goto hit_next;
729 goto search_again;
730
731out:
732 spin_unlock(&tree->lock);
733 if (prealloc)
734 free_extent_state(prealloc);
735
736 return 0;
737
738search_again:
739 if (start > end)
740 goto out;
741 spin_unlock(&tree->lock);
742 if (gfpflags_allow_blocking(mask))
743 cond_resched();
744 goto again;
745}
746
747static void wait_on_state(struct extent_io_tree *tree,
748 struct extent_state *state)
749 __releases(tree->lock)
750 __acquires(tree->lock)
751{
752 DEFINE_WAIT(wait);
753 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
754 spin_unlock(&tree->lock);
755 schedule();
756 spin_lock(&tree->lock);
757 finish_wait(&state->wq, &wait);
758}
759
760/*
761 * waits for one or more bits to clear on a range in the state tree.
762 * The range [start, end] is inclusive.
763 * The tree lock is taken by this function
764 */
765static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
766 unsigned long bits)
767{
768 struct extent_state *state;
769 struct rb_node *node;
770
771 btrfs_debug_check_extent_io_range(tree, start, end);
772
773 spin_lock(&tree->lock);
774again:
775 while (1) {
776 /*
777 * this search will find all the extents that end after
778 * our range starts
779 */
780 node = tree_search(tree, start);
781process_node:
782 if (!node)
783 break;
784
785 state = rb_entry(node, struct extent_state, rb_node);
786
787 if (state->start > end)
788 goto out;
789
790 if (state->state & bits) {
791 start = state->start;
792 atomic_inc(&state->refs);
793 wait_on_state(tree, state);
794 free_extent_state(state);
795 goto again;
796 }
797 start = state->end + 1;
798
799 if (start > end)
800 break;
801
802 if (!cond_resched_lock(&tree->lock)) {
803 node = rb_next(node);
804 goto process_node;
805 }
806 }
807out:
808 spin_unlock(&tree->lock);
809}
810
811static void set_state_bits(struct extent_io_tree *tree,
812 struct extent_state *state,
813 unsigned *bits, struct extent_changeset *changeset)
814{
815 unsigned bits_to_set = *bits & ~EXTENT_CTLBITS;
816
817 set_state_cb(tree, state, bits);
818 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
819 u64 range = state->end - state->start + 1;
820 tree->dirty_bytes += range;
821 }
822 add_extent_changeset(state, bits_to_set, changeset, 1);
823 state->state |= bits_to_set;
824}
825
826static void cache_state_if_flags(struct extent_state *state,
827 struct extent_state **cached_ptr,
828 unsigned flags)
829{
830 if (cached_ptr && !(*cached_ptr)) {
831 if (!flags || (state->state & flags)) {
832 *cached_ptr = state;
833 atomic_inc(&state->refs);
834 }
835 }
836}
837
838static void cache_state(struct extent_state *state,
839 struct extent_state **cached_ptr)
840{
841 return cache_state_if_flags(state, cached_ptr,
842 EXTENT_IOBITS | EXTENT_BOUNDARY);
843}
844
845/*
846 * set some bits on a range in the tree. This may require allocations or
847 * sleeping, so the gfp mask is used to indicate what is allowed.
848 *
849 * If any of the exclusive bits are set, this will fail with -EEXIST if some
850 * part of the range already has the desired bits set. The start of the
851 * existing range is returned in failed_start in this case.
852 *
853 * [start, end] is inclusive This takes the tree lock.
854 */
855
856static int __must_check
857__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
858 unsigned bits, unsigned exclusive_bits,
859 u64 *failed_start, struct extent_state **cached_state,
860 gfp_t mask, struct extent_changeset *changeset)
861{
862 struct extent_state *state;
863 struct extent_state *prealloc = NULL;
864 struct rb_node *node;
865 struct rb_node **p;
866 struct rb_node *parent;
867 int err = 0;
868 u64 last_start;
869 u64 last_end;
870
871 btrfs_debug_check_extent_io_range(tree, start, end);
872
873 bits |= EXTENT_FIRST_DELALLOC;
874again:
875 if (!prealloc && gfpflags_allow_blocking(mask)) {
876 prealloc = alloc_extent_state(mask);
877 BUG_ON(!prealloc);
878 }
879
880 spin_lock(&tree->lock);
881 if (cached_state && *cached_state) {
882 state = *cached_state;
883 if (state->start <= start && state->end > start &&
884 extent_state_in_tree(state)) {
885 node = &state->rb_node;
886 goto hit_next;
887 }
888 }
889 /*
890 * this search will find all the extents that end after
891 * our range starts.
892 */
893 node = tree_search_for_insert(tree, start, &p, &parent);
894 if (!node) {
895 prealloc = alloc_extent_state_atomic(prealloc);
896 BUG_ON(!prealloc);
897 err = insert_state(tree, prealloc, start, end,
898 &p, &parent, &bits, changeset);
899 if (err)
900 extent_io_tree_panic(tree, err);
901
902 cache_state(prealloc, cached_state);
903 prealloc = NULL;
904 goto out;
905 }
906 state = rb_entry(node, struct extent_state, rb_node);
907hit_next:
908 last_start = state->start;
909 last_end = state->end;
910
911 /*
912 * | ---- desired range ---- |
913 * | state |
914 *
915 * Just lock what we found and keep going
916 */
917 if (state->start == start && state->end <= end) {
918 if (state->state & exclusive_bits) {
919 *failed_start = state->start;
920 err = -EEXIST;
921 goto out;
922 }
923
924 set_state_bits(tree, state, &bits, changeset);
925 cache_state(state, cached_state);
926 merge_state(tree, state);
927 if (last_end == (u64)-1)
928 goto out;
929 start = last_end + 1;
930 state = next_state(state);
931 if (start < end && state && state->start == start &&
932 !need_resched())
933 goto hit_next;
934 goto search_again;
935 }
936
937 /*
938 * | ---- desired range ---- |
939 * | state |
940 * or
941 * | ------------- state -------------- |
942 *
943 * We need to split the extent we found, and may flip bits on
944 * second half.
945 *
946 * If the extent we found extends past our
947 * range, we just split and search again. It'll get split
948 * again the next time though.
949 *
950 * If the extent we found is inside our range, we set the
951 * desired bit on it.
952 */
953 if (state->start < start) {
954 if (state->state & exclusive_bits) {
955 *failed_start = start;
956 err = -EEXIST;
957 goto out;
958 }
959
960 prealloc = alloc_extent_state_atomic(prealloc);
961 BUG_ON(!prealloc);
962 err = split_state(tree, state, prealloc, start);
963 if (err)
964 extent_io_tree_panic(tree, err);
965
966 prealloc = NULL;
967 if (err)
968 goto out;
969 if (state->end <= end) {
970 set_state_bits(tree, state, &bits, changeset);
971 cache_state(state, cached_state);
972 merge_state(tree, state);
973 if (last_end == (u64)-1)
974 goto out;
975 start = last_end + 1;
976 state = next_state(state);
977 if (start < end && state && state->start == start &&
978 !need_resched())
979 goto hit_next;
980 }
981 goto search_again;
982 }
983 /*
984 * | ---- desired range ---- |
985 * | state | or | state |
986 *
987 * There's a hole, we need to insert something in it and
988 * ignore the extent we found.
989 */
990 if (state->start > start) {
991 u64 this_end;
992 if (end < last_start)
993 this_end = end;
994 else
995 this_end = last_start - 1;
996
997 prealloc = alloc_extent_state_atomic(prealloc);
998 BUG_ON(!prealloc);
999
1000 /*
1001 * Avoid to free 'prealloc' if it can be merged with
1002 * the later extent.
1003 */
1004 err = insert_state(tree, prealloc, start, this_end,
1005 NULL, NULL, &bits, changeset);
1006 if (err)
1007 extent_io_tree_panic(tree, err);
1008
1009 cache_state(prealloc, cached_state);
1010 prealloc = NULL;
1011 start = this_end + 1;
1012 goto search_again;
1013 }
1014 /*
1015 * | ---- desired range ---- |
1016 * | state |
1017 * We need to split the extent, and set the bit
1018 * on the first half
1019 */
1020 if (state->start <= end && state->end > end) {
1021 if (state->state & exclusive_bits) {
1022 *failed_start = start;
1023 err = -EEXIST;
1024 goto out;
1025 }
1026
1027 prealloc = alloc_extent_state_atomic(prealloc);
1028 BUG_ON(!prealloc);
1029 err = split_state(tree, state, prealloc, end + 1);
1030 if (err)
1031 extent_io_tree_panic(tree, err);
1032
1033 set_state_bits(tree, prealloc, &bits, changeset);
1034 cache_state(prealloc, cached_state);
1035 merge_state(tree, prealloc);
1036 prealloc = NULL;
1037 goto out;
1038 }
1039
1040 goto search_again;
1041
1042out:
1043 spin_unlock(&tree->lock);
1044 if (prealloc)
1045 free_extent_state(prealloc);
1046
1047 return err;
1048
1049search_again:
1050 if (start > end)
1051 goto out;
1052 spin_unlock(&tree->lock);
1053 if (gfpflags_allow_blocking(mask))
1054 cond_resched();
1055 goto again;
1056}
1057
1058int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1059 unsigned bits, u64 * failed_start,
1060 struct extent_state **cached_state, gfp_t mask)
1061{
1062 return __set_extent_bit(tree, start, end, bits, 0, failed_start,
1063 cached_state, mask, NULL);
1064}
1065
1066
1067/**
1068 * convert_extent_bit - convert all bits in a given range from one bit to
1069 * another
1070 * @tree: the io tree to search
1071 * @start: the start offset in bytes
1072 * @end: the end offset in bytes (inclusive)
1073 * @bits: the bits to set in this range
1074 * @clear_bits: the bits to clear in this range
1075 * @cached_state: state that we're going to cache
1076 * @mask: the allocation mask
1077 *
1078 * This will go through and set bits for the given range. If any states exist
1079 * already in this range they are set with the given bit and cleared of the
1080 * clear_bits. This is only meant to be used by things that are mergeable, ie
1081 * converting from say DELALLOC to DIRTY. This is not meant to be used with
1082 * boundary bits like LOCK.
1083 */
1084int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1085 unsigned bits, unsigned clear_bits,
1086 struct extent_state **cached_state, gfp_t mask)
1087{
1088 struct extent_state *state;
1089 struct extent_state *prealloc = NULL;
1090 struct rb_node *node;
1091 struct rb_node **p;
1092 struct rb_node *parent;
1093 int err = 0;
1094 u64 last_start;
1095 u64 last_end;
1096 bool first_iteration = true;
1097
1098 btrfs_debug_check_extent_io_range(tree, start, end);
1099
1100again:
1101 if (!prealloc && gfpflags_allow_blocking(mask)) {
1102 /*
1103 * Best effort, don't worry if extent state allocation fails
1104 * here for the first iteration. We might have a cached state
1105 * that matches exactly the target range, in which case no
1106 * extent state allocations are needed. We'll only know this
1107 * after locking the tree.
1108 */
1109 prealloc = alloc_extent_state(mask);
1110 if (!prealloc && !first_iteration)
1111 return -ENOMEM;
1112 }
1113
1114 spin_lock(&tree->lock);
1115 if (cached_state && *cached_state) {
1116 state = *cached_state;
1117 if (state->start <= start && state->end > start &&
1118 extent_state_in_tree(state)) {
1119 node = &state->rb_node;
1120 goto hit_next;
1121 }
1122 }
1123
1124 /*
1125 * this search will find all the extents that end after
1126 * our range starts.
1127 */
1128 node = tree_search_for_insert(tree, start, &p, &parent);
1129 if (!node) {
1130 prealloc = alloc_extent_state_atomic(prealloc);
1131 if (!prealloc) {
1132 err = -ENOMEM;
1133 goto out;
1134 }
1135 err = insert_state(tree, prealloc, start, end,
1136 &p, &parent, &bits, NULL);
1137 if (err)
1138 extent_io_tree_panic(tree, err);
1139 cache_state(prealloc, cached_state);
1140 prealloc = NULL;
1141 goto out;
1142 }
1143 state = rb_entry(node, struct extent_state, rb_node);
1144hit_next:
1145 last_start = state->start;
1146 last_end = state->end;
1147
1148 /*
1149 * | ---- desired range ---- |
1150 * | state |
1151 *
1152 * Just lock what we found and keep going
1153 */
1154 if (state->start == start && state->end <= end) {
1155 set_state_bits(tree, state, &bits, NULL);
1156 cache_state(state, cached_state);
1157 state = clear_state_bit(tree, state, &clear_bits, 0, NULL);
1158 if (last_end == (u64)-1)
1159 goto out;
1160 start = last_end + 1;
1161 if (start < end && state && state->start == start &&
1162 !need_resched())
1163 goto hit_next;
1164 goto search_again;
1165 }
1166
1167 /*
1168 * | ---- desired range ---- |
1169 * | state |
1170 * or
1171 * | ------------- state -------------- |
1172 *
1173 * We need to split the extent we found, and may flip bits on
1174 * second half.
1175 *
1176 * If the extent we found extends past our
1177 * range, we just split and search again. It'll get split
1178 * again the next time though.
1179 *
1180 * If the extent we found is inside our range, we set the
1181 * desired bit on it.
1182 */
1183 if (state->start < start) {
1184 prealloc = alloc_extent_state_atomic(prealloc);
1185 if (!prealloc) {
1186 err = -ENOMEM;
1187 goto out;
1188 }
1189 err = split_state(tree, state, prealloc, start);
1190 if (err)
1191 extent_io_tree_panic(tree, err);
1192 prealloc = NULL;
1193 if (err)
1194 goto out;
1195 if (state->end <= end) {
1196 set_state_bits(tree, state, &bits, NULL);
1197 cache_state(state, cached_state);
1198 state = clear_state_bit(tree, state, &clear_bits, 0,
1199 NULL);
1200 if (last_end == (u64)-1)
1201 goto out;
1202 start = last_end + 1;
1203 if (start < end && state && state->start == start &&
1204 !need_resched())
1205 goto hit_next;
1206 }
1207 goto search_again;
1208 }
1209 /*
1210 * | ---- desired range ---- |
1211 * | state | or | state |
1212 *
1213 * There's a hole, we need to insert something in it and
1214 * ignore the extent we found.
1215 */
1216 if (state->start > start) {
1217 u64 this_end;
1218 if (end < last_start)
1219 this_end = end;
1220 else
1221 this_end = last_start - 1;
1222
1223 prealloc = alloc_extent_state_atomic(prealloc);
1224 if (!prealloc) {
1225 err = -ENOMEM;
1226 goto out;
1227 }
1228
1229 /*
1230 * Avoid to free 'prealloc' if it can be merged with
1231 * the later extent.
1232 */
1233 err = insert_state(tree, prealloc, start, this_end,
1234 NULL, NULL, &bits, NULL);
1235 if (err)
1236 extent_io_tree_panic(tree, err);
1237 cache_state(prealloc, cached_state);
1238 prealloc = NULL;
1239 start = this_end + 1;
1240 goto search_again;
1241 }
1242 /*
1243 * | ---- desired range ---- |
1244 * | state |
1245 * We need to split the extent, and set the bit
1246 * on the first half
1247 */
1248 if (state->start <= end && state->end > end) {
1249 prealloc = alloc_extent_state_atomic(prealloc);
1250 if (!prealloc) {
1251 err = -ENOMEM;
1252 goto out;
1253 }
1254
1255 err = split_state(tree, state, prealloc, end + 1);
1256 if (err)
1257 extent_io_tree_panic(tree, err);
1258
1259 set_state_bits(tree, prealloc, &bits, NULL);
1260 cache_state(prealloc, cached_state);
1261 clear_state_bit(tree, prealloc, &clear_bits, 0, NULL);
1262 prealloc = NULL;
1263 goto out;
1264 }
1265
1266 goto search_again;
1267
1268out:
1269 spin_unlock(&tree->lock);
1270 if (prealloc)
1271 free_extent_state(prealloc);
1272
1273 return err;
1274
1275search_again:
1276 if (start > end)
1277 goto out;
1278 spin_unlock(&tree->lock);
1279 if (gfpflags_allow_blocking(mask))
1280 cond_resched();
1281 first_iteration = false;
1282 goto again;
1283}
1284
1285/* wrappers around set/clear extent bit */
1286int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1287 unsigned bits, gfp_t mask,
1288 struct extent_changeset *changeset)
1289{
1290 /*
1291 * We don't support EXTENT_LOCKED yet, as current changeset will
1292 * record any bits changed, so for EXTENT_LOCKED case, it will
1293 * either fail with -EEXIST or changeset will record the whole
1294 * range.
1295 */
1296 BUG_ON(bits & EXTENT_LOCKED);
1297
1298 return __set_extent_bit(tree, start, end, bits, 0, NULL, NULL, mask,
1299 changeset);
1300}
1301
1302int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1303 unsigned bits, int wake, int delete,
1304 struct extent_state **cached, gfp_t mask)
1305{
1306 return __clear_extent_bit(tree, start, end, bits, wake, delete,
1307 cached, mask, NULL);
1308}
1309
1310int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1311 unsigned bits, gfp_t mask,
1312 struct extent_changeset *changeset)
1313{
1314 /*
1315 * Don't support EXTENT_LOCKED case, same reason as
1316 * set_record_extent_bits().
1317 */
1318 BUG_ON(bits & EXTENT_LOCKED);
1319
1320 return __clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask,
1321 changeset);
1322}
1323
1324/*
1325 * either insert or lock state struct between start and end use mask to tell
1326 * us if waiting is desired.
1327 */
1328int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1329 struct extent_state **cached_state)
1330{
1331 int err;
1332 u64 failed_start;
1333
1334 while (1) {
1335 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED,
1336 EXTENT_LOCKED, &failed_start,
1337 cached_state, GFP_NOFS, NULL);
1338 if (err == -EEXIST) {
1339 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
1340 start = failed_start;
1341 } else
1342 break;
1343 WARN_ON(start > end);
1344 }
1345 return err;
1346}
1347
1348int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1349{
1350 int err;
1351 u64 failed_start;
1352
1353 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1354 &failed_start, NULL, GFP_NOFS, NULL);
1355 if (err == -EEXIST) {
1356 if (failed_start > start)
1357 clear_extent_bit(tree, start, failed_start - 1,
1358 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
1359 return 0;
1360 }
1361 return 1;
1362}
1363
1364void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
1365{
1366 unsigned long index = start >> PAGE_SHIFT;
1367 unsigned long end_index = end >> PAGE_SHIFT;
1368 struct page *page;
1369
1370 while (index <= end_index) {
1371 page = find_get_page(inode->i_mapping, index);
1372 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1373 clear_page_dirty_for_io(page);
1374 put_page(page);
1375 index++;
1376 }
1377}
1378
1379void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
1380{
1381 unsigned long index = start >> PAGE_SHIFT;
1382 unsigned long end_index = end >> PAGE_SHIFT;
1383 struct page *page;
1384
1385 while (index <= end_index) {
1386 page = find_get_page(inode->i_mapping, index);
1387 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1388 __set_page_dirty_nobuffers(page);
1389 account_page_redirty(page);
1390 put_page(page);
1391 index++;
1392 }
1393}
1394
1395/*
1396 * helper function to set both pages and extents in the tree writeback
1397 */
1398static void set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1399{
1400 unsigned long index = start >> PAGE_SHIFT;
1401 unsigned long end_index = end >> PAGE_SHIFT;
1402 struct page *page;
1403
1404 while (index <= end_index) {
1405 page = find_get_page(tree->mapping, index);
1406 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1407 set_page_writeback(page);
1408 put_page(page);
1409 index++;
1410 }
1411}
1412
1413/* find the first state struct with 'bits' set after 'start', and
1414 * return it. tree->lock must be held. NULL will returned if
1415 * nothing was found after 'start'
1416 */
1417static struct extent_state *
1418find_first_extent_bit_state(struct extent_io_tree *tree,
1419 u64 start, unsigned bits)
1420{
1421 struct rb_node *node;
1422 struct extent_state *state;
1423
1424 /*
1425 * this search will find all the extents that end after
1426 * our range starts.
1427 */
1428 node = tree_search(tree, start);
1429 if (!node)
1430 goto out;
1431
1432 while (1) {
1433 state = rb_entry(node, struct extent_state, rb_node);
1434 if (state->end >= start && (state->state & bits))
1435 return state;
1436
1437 node = rb_next(node);
1438 if (!node)
1439 break;
1440 }
1441out:
1442 return NULL;
1443}
1444
1445/*
1446 * find the first offset in the io tree with 'bits' set. zero is
1447 * returned if we find something, and *start_ret and *end_ret are
1448 * set to reflect the state struct that was found.
1449 *
1450 * If nothing was found, 1 is returned. If found something, return 0.
1451 */
1452int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1453 u64 *start_ret, u64 *end_ret, unsigned bits,
1454 struct extent_state **cached_state)
1455{
1456 struct extent_state *state;
1457 struct rb_node *n;
1458 int ret = 1;
1459
1460 spin_lock(&tree->lock);
1461 if (cached_state && *cached_state) {
1462 state = *cached_state;
1463 if (state->end == start - 1 && extent_state_in_tree(state)) {
1464 n = rb_next(&state->rb_node);
1465 while (n) {
1466 state = rb_entry(n, struct extent_state,
1467 rb_node);
1468 if (state->state & bits)
1469 goto got_it;
1470 n = rb_next(n);
1471 }
1472 free_extent_state(*cached_state);
1473 *cached_state = NULL;
1474 goto out;
1475 }
1476 free_extent_state(*cached_state);
1477 *cached_state = NULL;
1478 }
1479
1480 state = find_first_extent_bit_state(tree, start, bits);
1481got_it:
1482 if (state) {
1483 cache_state_if_flags(state, cached_state, 0);
1484 *start_ret = state->start;
1485 *end_ret = state->end;
1486 ret = 0;
1487 }
1488out:
1489 spin_unlock(&tree->lock);
1490 return ret;
1491}
1492
1493/*
1494 * find a contiguous range of bytes in the file marked as delalloc, not
1495 * more than 'max_bytes'. start and end are used to return the range,
1496 *
1497 * 1 is returned if we find something, 0 if nothing was in the tree
1498 */
1499static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1500 u64 *start, u64 *end, u64 max_bytes,
1501 struct extent_state **cached_state)
1502{
1503 struct rb_node *node;
1504 struct extent_state *state;
1505 u64 cur_start = *start;
1506 u64 found = 0;
1507 u64 total_bytes = 0;
1508
1509 spin_lock(&tree->lock);
1510
1511 /*
1512 * this search will find all the extents that end after
1513 * our range starts.
1514 */
1515 node = tree_search(tree, cur_start);
1516 if (!node) {
1517 if (!found)
1518 *end = (u64)-1;
1519 goto out;
1520 }
1521
1522 while (1) {
1523 state = rb_entry(node, struct extent_state, rb_node);
1524 if (found && (state->start != cur_start ||
1525 (state->state & EXTENT_BOUNDARY))) {
1526 goto out;
1527 }
1528 if (!(state->state & EXTENT_DELALLOC)) {
1529 if (!found)
1530 *end = state->end;
1531 goto out;
1532 }
1533 if (!found) {
1534 *start = state->start;
1535 *cached_state = state;
1536 atomic_inc(&state->refs);
1537 }
1538 found++;
1539 *end = state->end;
1540 cur_start = state->end + 1;
1541 node = rb_next(node);
1542 total_bytes += state->end - state->start + 1;
1543 if (total_bytes >= max_bytes)
1544 break;
1545 if (!node)
1546 break;
1547 }
1548out:
1549 spin_unlock(&tree->lock);
1550 return found;
1551}
1552
1553static noinline void __unlock_for_delalloc(struct inode *inode,
1554 struct page *locked_page,
1555 u64 start, u64 end)
1556{
1557 int ret;
1558 struct page *pages[16];
1559 unsigned long index = start >> PAGE_SHIFT;
1560 unsigned long end_index = end >> PAGE_SHIFT;
1561 unsigned long nr_pages = end_index - index + 1;
1562 int i;
1563
1564 if (index == locked_page->index && end_index == index)
1565 return;
1566
1567 while (nr_pages > 0) {
1568 ret = find_get_pages_contig(inode->i_mapping, index,
1569 min_t(unsigned long, nr_pages,
1570 ARRAY_SIZE(pages)), pages);
1571 for (i = 0; i < ret; i++) {
1572 if (pages[i] != locked_page)
1573 unlock_page(pages[i]);
1574 put_page(pages[i]);
1575 }
1576 nr_pages -= ret;
1577 index += ret;
1578 cond_resched();
1579 }
1580}
1581
1582static noinline int lock_delalloc_pages(struct inode *inode,
1583 struct page *locked_page,
1584 u64 delalloc_start,
1585 u64 delalloc_end)
1586{
1587 unsigned long index = delalloc_start >> PAGE_SHIFT;
1588 unsigned long start_index = index;
1589 unsigned long end_index = delalloc_end >> PAGE_SHIFT;
1590 unsigned long pages_locked = 0;
1591 struct page *pages[16];
1592 unsigned long nrpages;
1593 int ret;
1594 int i;
1595
1596 /* the caller is responsible for locking the start index */
1597 if (index == locked_page->index && index == end_index)
1598 return 0;
1599
1600 /* skip the page at the start index */
1601 nrpages = end_index - index + 1;
1602 while (nrpages > 0) {
1603 ret = find_get_pages_contig(inode->i_mapping, index,
1604 min_t(unsigned long,
1605 nrpages, ARRAY_SIZE(pages)), pages);
1606 if (ret == 0) {
1607 ret = -EAGAIN;
1608 goto done;
1609 }
1610 /* now we have an array of pages, lock them all */
1611 for (i = 0; i < ret; i++) {
1612 /*
1613 * the caller is taking responsibility for
1614 * locked_page
1615 */
1616 if (pages[i] != locked_page) {
1617 lock_page(pages[i]);
1618 if (!PageDirty(pages[i]) ||
1619 pages[i]->mapping != inode->i_mapping) {
1620 ret = -EAGAIN;
1621 unlock_page(pages[i]);
1622 put_page(pages[i]);
1623 goto done;
1624 }
1625 }
1626 put_page(pages[i]);
1627 pages_locked++;
1628 }
1629 nrpages -= ret;
1630 index += ret;
1631 cond_resched();
1632 }
1633 ret = 0;
1634done:
1635 if (ret && pages_locked) {
1636 __unlock_for_delalloc(inode, locked_page,
1637 delalloc_start,
1638 ((u64)(start_index + pages_locked - 1)) <<
1639 PAGE_SHIFT);
1640 }
1641 return ret;
1642}
1643
1644/*
1645 * find a contiguous range of bytes in the file marked as delalloc, not
1646 * more than 'max_bytes'. start and end are used to return the range,
1647 *
1648 * 1 is returned if we find something, 0 if nothing was in the tree
1649 */
1650STATIC u64 find_lock_delalloc_range(struct inode *inode,
1651 struct extent_io_tree *tree,
1652 struct page *locked_page, u64 *start,
1653 u64 *end, u64 max_bytes)
1654{
1655 u64 delalloc_start;
1656 u64 delalloc_end;
1657 u64 found;
1658 struct extent_state *cached_state = NULL;
1659 int ret;
1660 int loops = 0;
1661
1662again:
1663 /* step one, find a bunch of delalloc bytes starting at start */
1664 delalloc_start = *start;
1665 delalloc_end = 0;
1666 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1667 max_bytes, &cached_state);
1668 if (!found || delalloc_end <= *start) {
1669 *start = delalloc_start;
1670 *end = delalloc_end;
1671 free_extent_state(cached_state);
1672 return 0;
1673 }
1674
1675 /*
1676 * start comes from the offset of locked_page. We have to lock
1677 * pages in order, so we can't process delalloc bytes before
1678 * locked_page
1679 */
1680 if (delalloc_start < *start)
1681 delalloc_start = *start;
1682
1683 /*
1684 * make sure to limit the number of pages we try to lock down
1685 */
1686 if (delalloc_end + 1 - delalloc_start > max_bytes)
1687 delalloc_end = delalloc_start + max_bytes - 1;
1688
1689 /* step two, lock all the pages after the page that has start */
1690 ret = lock_delalloc_pages(inode, locked_page,
1691 delalloc_start, delalloc_end);
1692 if (ret == -EAGAIN) {
1693 /* some of the pages are gone, lets avoid looping by
1694 * shortening the size of the delalloc range we're searching
1695 */
1696 free_extent_state(cached_state);
1697 cached_state = NULL;
1698 if (!loops) {
1699 max_bytes = PAGE_SIZE;
1700 loops = 1;
1701 goto again;
1702 } else {
1703 found = 0;
1704 goto out_failed;
1705 }
1706 }
1707 BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
1708
1709 /* step three, lock the state bits for the whole range */
1710 lock_extent_bits(tree, delalloc_start, delalloc_end, &cached_state);
1711
1712 /* then test to make sure it is all still delalloc */
1713 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1714 EXTENT_DELALLOC, 1, cached_state);
1715 if (!ret) {
1716 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1717 &cached_state, GFP_NOFS);
1718 __unlock_for_delalloc(inode, locked_page,
1719 delalloc_start, delalloc_end);
1720 cond_resched();
1721 goto again;
1722 }
1723 free_extent_state(cached_state);
1724 *start = delalloc_start;
1725 *end = delalloc_end;
1726out_failed:
1727 return found;
1728}
1729
1730void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
1731 struct page *locked_page,
1732 unsigned clear_bits,
1733 unsigned long page_ops)
1734{
1735 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
1736 int ret;
1737 struct page *pages[16];
1738 unsigned long index = start >> PAGE_SHIFT;
1739 unsigned long end_index = end >> PAGE_SHIFT;
1740 unsigned long nr_pages = end_index - index + 1;
1741 int i;
1742
1743 clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1744 if (page_ops == 0)
1745 return;
1746
1747 if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
1748 mapping_set_error(inode->i_mapping, -EIO);
1749
1750 while (nr_pages > 0) {
1751 ret = find_get_pages_contig(inode->i_mapping, index,
1752 min_t(unsigned long,
1753 nr_pages, ARRAY_SIZE(pages)), pages);
1754 for (i = 0; i < ret; i++) {
1755
1756 if (page_ops & PAGE_SET_PRIVATE2)
1757 SetPagePrivate2(pages[i]);
1758
1759 if (pages[i] == locked_page) {
1760 put_page(pages[i]);
1761 continue;
1762 }
1763 if (page_ops & PAGE_CLEAR_DIRTY)
1764 clear_page_dirty_for_io(pages[i]);
1765 if (page_ops & PAGE_SET_WRITEBACK)
1766 set_page_writeback(pages[i]);
1767 if (page_ops & PAGE_SET_ERROR)
1768 SetPageError(pages[i]);
1769 if (page_ops & PAGE_END_WRITEBACK)
1770 end_page_writeback(pages[i]);
1771 if (page_ops & PAGE_UNLOCK)
1772 unlock_page(pages[i]);
1773 put_page(pages[i]);
1774 }
1775 nr_pages -= ret;
1776 index += ret;
1777 cond_resched();
1778 }
1779}
1780
1781/*
1782 * count the number of bytes in the tree that have a given bit(s)
1783 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1784 * cached. The total number found is returned.
1785 */
1786u64 count_range_bits(struct extent_io_tree *tree,
1787 u64 *start, u64 search_end, u64 max_bytes,
1788 unsigned bits, int contig)
1789{
1790 struct rb_node *node;
1791 struct extent_state *state;
1792 u64 cur_start = *start;
1793 u64 total_bytes = 0;
1794 u64 last = 0;
1795 int found = 0;
1796
1797 if (WARN_ON(search_end <= cur_start))
1798 return 0;
1799
1800 spin_lock(&tree->lock);
1801 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1802 total_bytes = tree->dirty_bytes;
1803 goto out;
1804 }
1805 /*
1806 * this search will find all the extents that end after
1807 * our range starts.
1808 */
1809 node = tree_search(tree, cur_start);
1810 if (!node)
1811 goto out;
1812
1813 while (1) {
1814 state = rb_entry(node, struct extent_state, rb_node);
1815 if (state->start > search_end)
1816 break;
1817 if (contig && found && state->start > last + 1)
1818 break;
1819 if (state->end >= cur_start && (state->state & bits) == bits) {
1820 total_bytes += min(search_end, state->end) + 1 -
1821 max(cur_start, state->start);
1822 if (total_bytes >= max_bytes)
1823 break;
1824 if (!found) {
1825 *start = max(cur_start, state->start);
1826 found = 1;
1827 }
1828 last = state->end;
1829 } else if (contig && found) {
1830 break;
1831 }
1832 node = rb_next(node);
1833 if (!node)
1834 break;
1835 }
1836out:
1837 spin_unlock(&tree->lock);
1838 return total_bytes;
1839}
1840
1841/*
1842 * set the private field for a given byte offset in the tree. If there isn't
1843 * an extent_state there already, this does nothing.
1844 */
1845static noinline int set_state_failrec(struct extent_io_tree *tree, u64 start,
1846 struct io_failure_record *failrec)
1847{
1848 struct rb_node *node;
1849 struct extent_state *state;
1850 int ret = 0;
1851
1852 spin_lock(&tree->lock);
1853 /*
1854 * this search will find all the extents that end after
1855 * our range starts.
1856 */
1857 node = tree_search(tree, start);
1858 if (!node) {
1859 ret = -ENOENT;
1860 goto out;
1861 }
1862 state = rb_entry(node, struct extent_state, rb_node);
1863 if (state->start != start) {
1864 ret = -ENOENT;
1865 goto out;
1866 }
1867 state->failrec = failrec;
1868out:
1869 spin_unlock(&tree->lock);
1870 return ret;
1871}
1872
1873static noinline int get_state_failrec(struct extent_io_tree *tree, u64 start,
1874 struct io_failure_record **failrec)
1875{
1876 struct rb_node *node;
1877 struct extent_state *state;
1878 int ret = 0;
1879
1880 spin_lock(&tree->lock);
1881 /*
1882 * this search will find all the extents that end after
1883 * our range starts.
1884 */
1885 node = tree_search(tree, start);
1886 if (!node) {
1887 ret = -ENOENT;
1888 goto out;
1889 }
1890 state = rb_entry(node, struct extent_state, rb_node);
1891 if (state->start != start) {
1892 ret = -ENOENT;
1893 goto out;
1894 }
1895 *failrec = state->failrec;
1896out:
1897 spin_unlock(&tree->lock);
1898 return ret;
1899}
1900
1901/*
1902 * searches a range in the state tree for a given mask.
1903 * If 'filled' == 1, this returns 1 only if every extent in the tree
1904 * has the bits set. Otherwise, 1 is returned if any bit in the
1905 * range is found set.
1906 */
1907int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1908 unsigned bits, int filled, struct extent_state *cached)
1909{
1910 struct extent_state *state = NULL;
1911 struct rb_node *node;
1912 int bitset = 0;
1913
1914 spin_lock(&tree->lock);
1915 if (cached && extent_state_in_tree(cached) && cached->start <= start &&
1916 cached->end > start)
1917 node = &cached->rb_node;
1918 else
1919 node = tree_search(tree, start);
1920 while (node && start <= end) {
1921 state = rb_entry(node, struct extent_state, rb_node);
1922
1923 if (filled && state->start > start) {
1924 bitset = 0;
1925 break;
1926 }
1927
1928 if (state->start > end)
1929 break;
1930
1931 if (state->state & bits) {
1932 bitset = 1;
1933 if (!filled)
1934 break;
1935 } else if (filled) {
1936 bitset = 0;
1937 break;
1938 }
1939
1940 if (state->end == (u64)-1)
1941 break;
1942
1943 start = state->end + 1;
1944 if (start > end)
1945 break;
1946 node = rb_next(node);
1947 if (!node) {
1948 if (filled)
1949 bitset = 0;
1950 break;
1951 }
1952 }
1953 spin_unlock(&tree->lock);
1954 return bitset;
1955}
1956
1957/*
1958 * helper function to set a given page up to date if all the
1959 * extents in the tree for that page are up to date
1960 */
1961static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1962{
1963 u64 start = page_offset(page);
1964 u64 end = start + PAGE_SIZE - 1;
1965 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1966 SetPageUptodate(page);
1967}
1968
1969int free_io_failure(struct inode *inode, struct io_failure_record *rec)
1970{
1971 int ret;
1972 int err = 0;
1973 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1974
1975 set_state_failrec(failure_tree, rec->start, NULL);
1976 ret = clear_extent_bits(failure_tree, rec->start,
1977 rec->start + rec->len - 1,
1978 EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1979 if (ret)
1980 err = ret;
1981
1982 ret = clear_extent_bits(&BTRFS_I(inode)->io_tree, rec->start,
1983 rec->start + rec->len - 1,
1984 EXTENT_DAMAGED, GFP_NOFS);
1985 if (ret && !err)
1986 err = ret;
1987
1988 kfree(rec);
1989 return err;
1990}
1991
1992/*
1993 * this bypasses the standard btrfs submit functions deliberately, as
1994 * the standard behavior is to write all copies in a raid setup. here we only
1995 * want to write the one bad copy. so we do the mapping for ourselves and issue
1996 * submit_bio directly.
1997 * to avoid any synchronization issues, wait for the data after writing, which
1998 * actually prevents the read that triggered the error from finishing.
1999 * currently, there can be no more than two copies of every data bit. thus,
2000 * exactly one rewrite is required.
2001 */
2002int repair_io_failure(struct inode *inode, u64 start, u64 length, u64 logical,
2003 struct page *page, unsigned int pg_offset, int mirror_num)
2004{
2005 struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2006 struct bio *bio;
2007 struct btrfs_device *dev;
2008 u64 map_length = 0;
2009 u64 sector;
2010 struct btrfs_bio *bbio = NULL;
2011 struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
2012 int ret;
2013
2014 ASSERT(!(fs_info->sb->s_flags & MS_RDONLY));
2015 BUG_ON(!mirror_num);
2016
2017 /* we can't repair anything in raid56 yet */
2018 if (btrfs_is_parity_mirror(map_tree, logical, length, mirror_num))
2019 return 0;
2020
2021 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2022 if (!bio)
2023 return -EIO;
2024 bio->bi_iter.bi_size = 0;
2025 map_length = length;
2026
2027 ret = btrfs_map_block(fs_info, WRITE, logical,
2028 &map_length, &bbio, mirror_num);
2029 if (ret) {
2030 bio_put(bio);
2031 return -EIO;
2032 }
2033 BUG_ON(mirror_num != bbio->mirror_num);
2034 sector = bbio->stripes[mirror_num-1].physical >> 9;
2035 bio->bi_iter.bi_sector = sector;
2036 dev = bbio->stripes[mirror_num-1].dev;
2037 btrfs_put_bbio(bbio);
2038 if (!dev || !dev->bdev || !dev->writeable) {
2039 bio_put(bio);
2040 return -EIO;
2041 }
2042 bio->bi_bdev = dev->bdev;
2043 bio_add_page(bio, page, length, pg_offset);
2044
2045 if (btrfsic_submit_bio_wait(WRITE_SYNC, bio)) {
2046 /* try to remap that extent elsewhere? */
2047 bio_put(bio);
2048 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2049 return -EIO;
2050 }
2051
2052 btrfs_info_rl_in_rcu(fs_info,
2053 "read error corrected: ino %llu off %llu (dev %s sector %llu)",
2054 btrfs_ino(inode), start,
2055 rcu_str_deref(dev->name), sector);
2056 bio_put(bio);
2057 return 0;
2058}
2059
2060int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb,
2061 int mirror_num)
2062{
2063 u64 start = eb->start;
2064 unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
2065 int ret = 0;
2066
2067 if (root->fs_info->sb->s_flags & MS_RDONLY)
2068 return -EROFS;
2069
2070 for (i = 0; i < num_pages; i++) {
2071 struct page *p = eb->pages[i];
2072
2073 ret = repair_io_failure(root->fs_info->btree_inode, start,
2074 PAGE_SIZE, start, p,
2075 start - page_offset(p), mirror_num);
2076 if (ret)
2077 break;
2078 start += PAGE_SIZE;
2079 }
2080
2081 return ret;
2082}
2083
2084/*
2085 * each time an IO finishes, we do a fast check in the IO failure tree
2086 * to see if we need to process or clean up an io_failure_record
2087 */
2088int clean_io_failure(struct inode *inode, u64 start, struct page *page,
2089 unsigned int pg_offset)
2090{
2091 u64 private;
2092 struct io_failure_record *failrec;
2093 struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2094 struct extent_state *state;
2095 int num_copies;
2096 int ret;
2097
2098 private = 0;
2099 ret = count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
2100 (u64)-1, 1, EXTENT_DIRTY, 0);
2101 if (!ret)
2102 return 0;
2103
2104 ret = get_state_failrec(&BTRFS_I(inode)->io_failure_tree, start,
2105 &failrec);
2106 if (ret)
2107 return 0;
2108
2109 BUG_ON(!failrec->this_mirror);
2110
2111 if (failrec->in_validation) {
2112 /* there was no real error, just free the record */
2113 pr_debug("clean_io_failure: freeing dummy error at %llu\n",
2114 failrec->start);
2115 goto out;
2116 }
2117 if (fs_info->sb->s_flags & MS_RDONLY)
2118 goto out;
2119
2120 spin_lock(&BTRFS_I(inode)->io_tree.lock);
2121 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
2122 failrec->start,
2123 EXTENT_LOCKED);
2124 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
2125
2126 if (state && state->start <= failrec->start &&
2127 state->end >= failrec->start + failrec->len - 1) {
2128 num_copies = btrfs_num_copies(fs_info, failrec->logical,
2129 failrec->len);
2130 if (num_copies > 1) {
2131 repair_io_failure(inode, start, failrec->len,
2132 failrec->logical, page,
2133 pg_offset, failrec->failed_mirror);
2134 }
2135 }
2136
2137out:
2138 free_io_failure(inode, failrec);
2139
2140 return 0;
2141}
2142
2143/*
2144 * Can be called when
2145 * - hold extent lock
2146 * - under ordered extent
2147 * - the inode is freeing
2148 */
2149void btrfs_free_io_failure_record(struct inode *inode, u64 start, u64 end)
2150{
2151 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2152 struct io_failure_record *failrec;
2153 struct extent_state *state, *next;
2154
2155 if (RB_EMPTY_ROOT(&failure_tree->state))
2156 return;
2157
2158 spin_lock(&failure_tree->lock);
2159 state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
2160 while (state) {
2161 if (state->start > end)
2162 break;
2163
2164 ASSERT(state->end <= end);
2165
2166 next = next_state(state);
2167
2168 failrec = state->failrec;
2169 free_extent_state(state);
2170 kfree(failrec);
2171
2172 state = next;
2173 }
2174 spin_unlock(&failure_tree->lock);
2175}
2176
2177int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
2178 struct io_failure_record **failrec_ret)
2179{
2180 struct io_failure_record *failrec;
2181 struct extent_map *em;
2182 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2183 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2184 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2185 int ret;
2186 u64 logical;
2187
2188 ret = get_state_failrec(failure_tree, start, &failrec);
2189 if (ret) {
2190 failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
2191 if (!failrec)
2192 return -ENOMEM;
2193
2194 failrec->start = start;
2195 failrec->len = end - start + 1;
2196 failrec->this_mirror = 0;
2197 failrec->bio_flags = 0;
2198 failrec->in_validation = 0;
2199
2200 read_lock(&em_tree->lock);
2201 em = lookup_extent_mapping(em_tree, start, failrec->len);
2202 if (!em) {
2203 read_unlock(&em_tree->lock);
2204 kfree(failrec);
2205 return -EIO;
2206 }
2207
2208 if (em->start > start || em->start + em->len <= start) {
2209 free_extent_map(em);
2210 em = NULL;
2211 }
2212 read_unlock(&em_tree->lock);
2213 if (!em) {
2214 kfree(failrec);
2215 return -EIO;
2216 }
2217
2218 logical = start - em->start;
2219 logical = em->block_start + logical;
2220 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2221 logical = em->block_start;
2222 failrec->bio_flags = EXTENT_BIO_COMPRESSED;
2223 extent_set_compress_type(&failrec->bio_flags,
2224 em->compress_type);
2225 }
2226
2227 pr_debug("Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu\n",
2228 logical, start, failrec->len);
2229
2230 failrec->logical = logical;
2231 free_extent_map(em);
2232
2233 /* set the bits in the private failure tree */
2234 ret = set_extent_bits(failure_tree, start, end,
2235 EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
2236 if (ret >= 0)
2237 ret = set_state_failrec(failure_tree, start, failrec);
2238 /* set the bits in the inode's tree */
2239 if (ret >= 0)
2240 ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED,
2241 GFP_NOFS);
2242 if (ret < 0) {
2243 kfree(failrec);
2244 return ret;
2245 }
2246 } else {
2247 pr_debug("Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d\n",
2248 failrec->logical, failrec->start, failrec->len,
2249 failrec->in_validation);
2250 /*
2251 * when data can be on disk more than twice, add to failrec here
2252 * (e.g. with a list for failed_mirror) to make
2253 * clean_io_failure() clean all those errors at once.
2254 */
2255 }
2256
2257 *failrec_ret = failrec;
2258
2259 return 0;
2260}
2261
2262int btrfs_check_repairable(struct inode *inode, struct bio *failed_bio,
2263 struct io_failure_record *failrec, int failed_mirror)
2264{
2265 int num_copies;
2266
2267 num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
2268 failrec->logical, failrec->len);
2269 if (num_copies == 1) {
2270 /*
2271 * we only have a single copy of the data, so don't bother with
2272 * all the retry and error correction code that follows. no
2273 * matter what the error is, it is very likely to persist.
2274 */
2275 pr_debug("Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
2276 num_copies, failrec->this_mirror, failed_mirror);
2277 return 0;
2278 }
2279
2280 /*
2281 * there are two premises:
2282 * a) deliver good data to the caller
2283 * b) correct the bad sectors on disk
2284 */
2285 if (failed_bio->bi_vcnt > 1) {
2286 /*
2287 * to fulfill b), we need to know the exact failing sectors, as
2288 * we don't want to rewrite any more than the failed ones. thus,
2289 * we need separate read requests for the failed bio
2290 *
2291 * if the following BUG_ON triggers, our validation request got
2292 * merged. we need separate requests for our algorithm to work.
2293 */
2294 BUG_ON(failrec->in_validation);
2295 failrec->in_validation = 1;
2296 failrec->this_mirror = failed_mirror;
2297 } else {
2298 /*
2299 * we're ready to fulfill a) and b) alongside. get a good copy
2300 * of the failed sector and if we succeed, we have setup
2301 * everything for repair_io_failure to do the rest for us.
2302 */
2303 if (failrec->in_validation) {
2304 BUG_ON(failrec->this_mirror != failed_mirror);
2305 failrec->in_validation = 0;
2306 failrec->this_mirror = 0;
2307 }
2308 failrec->failed_mirror = failed_mirror;
2309 failrec->this_mirror++;
2310 if (failrec->this_mirror == failed_mirror)
2311 failrec->this_mirror++;
2312 }
2313
2314 if (failrec->this_mirror > num_copies) {
2315 pr_debug("Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
2316 num_copies, failrec->this_mirror, failed_mirror);
2317 return 0;
2318 }
2319
2320 return 1;
2321}
2322
2323
2324struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
2325 struct io_failure_record *failrec,
2326 struct page *page, int pg_offset, int icsum,
2327 bio_end_io_t *endio_func, void *data)
2328{
2329 struct bio *bio;
2330 struct btrfs_io_bio *btrfs_failed_bio;
2331 struct btrfs_io_bio *btrfs_bio;
2332
2333 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2334 if (!bio)
2335 return NULL;
2336
2337 bio->bi_end_io = endio_func;
2338 bio->bi_iter.bi_sector = failrec->logical >> 9;
2339 bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
2340 bio->bi_iter.bi_size = 0;
2341 bio->bi_private = data;
2342
2343 btrfs_failed_bio = btrfs_io_bio(failed_bio);
2344 if (btrfs_failed_bio->csum) {
2345 struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2346 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
2347
2348 btrfs_bio = btrfs_io_bio(bio);
2349 btrfs_bio->csum = btrfs_bio->csum_inline;
2350 icsum *= csum_size;
2351 memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
2352 csum_size);
2353 }
2354
2355 bio_add_page(bio, page, failrec->len, pg_offset);
2356
2357 return bio;
2358}
2359
2360/*
2361 * this is a generic handler for readpage errors (default
2362 * readpage_io_failed_hook). if other copies exist, read those and write back
2363 * good data to the failed position. does not investigate in remapping the
2364 * failed extent elsewhere, hoping the device will be smart enough to do this as
2365 * needed
2366 */
2367
2368static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
2369 struct page *page, u64 start, u64 end,
2370 int failed_mirror)
2371{
2372 struct io_failure_record *failrec;
2373 struct inode *inode = page->mapping->host;
2374 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2375 struct bio *bio;
2376 int read_mode;
2377 int ret;
2378
2379 BUG_ON(failed_bio->bi_rw & REQ_WRITE);
2380
2381 ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
2382 if (ret)
2383 return ret;
2384
2385 ret = btrfs_check_repairable(inode, failed_bio, failrec, failed_mirror);
2386 if (!ret) {
2387 free_io_failure(inode, failrec);
2388 return -EIO;
2389 }
2390
2391 if (failed_bio->bi_vcnt > 1)
2392 read_mode = READ_SYNC | REQ_FAILFAST_DEV;
2393 else
2394 read_mode = READ_SYNC;
2395
2396 phy_offset >>= inode->i_sb->s_blocksize_bits;
2397 bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
2398 start - page_offset(page),
2399 (int)phy_offset, failed_bio->bi_end_io,
2400 NULL);
2401 if (!bio) {
2402 free_io_failure(inode, failrec);
2403 return -EIO;
2404 }
2405
2406 pr_debug("Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d\n",
2407 read_mode, failrec->this_mirror, failrec->in_validation);
2408
2409 ret = tree->ops->submit_bio_hook(inode, read_mode, bio,
2410 failrec->this_mirror,
2411 failrec->bio_flags, 0);
2412 if (ret) {
2413 free_io_failure(inode, failrec);
2414 bio_put(bio);
2415 }
2416
2417 return ret;
2418}
2419
2420/* lots and lots of room for performance fixes in the end_bio funcs */
2421
2422void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
2423{
2424 int uptodate = (err == 0);
2425 struct extent_io_tree *tree;
2426 int ret = 0;
2427
2428 tree = &BTRFS_I(page->mapping->host)->io_tree;
2429
2430 if (tree->ops && tree->ops->writepage_end_io_hook) {
2431 ret = tree->ops->writepage_end_io_hook(page, start,
2432 end, NULL, uptodate);
2433 if (ret)
2434 uptodate = 0;
2435 }
2436
2437 if (!uptodate) {
2438 ClearPageUptodate(page);
2439 SetPageError(page);
2440 ret = ret < 0 ? ret : -EIO;
2441 mapping_set_error(page->mapping, ret);
2442 }
2443}
2444
2445/*
2446 * after a writepage IO is done, we need to:
2447 * clear the uptodate bits on error
2448 * clear the writeback bits in the extent tree for this IO
2449 * end_page_writeback if the page has no more pending IO
2450 *
2451 * Scheduling is not allowed, so the extent state tree is expected
2452 * to have one and only one object corresponding to this IO.
2453 */
2454static void end_bio_extent_writepage(struct bio *bio)
2455{
2456 struct bio_vec *bvec;
2457 u64 start;
2458 u64 end;
2459 int i;
2460
2461 bio_for_each_segment_all(bvec, bio, i) {
2462 struct page *page = bvec->bv_page;
2463
2464 /* We always issue full-page reads, but if some block
2465 * in a page fails to read, blk_update_request() will
2466 * advance bv_offset and adjust bv_len to compensate.
2467 * Print a warning for nonzero offsets, and an error
2468 * if they don't add up to a full page. */
2469 if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2470 if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2471 btrfs_err(BTRFS_I(page->mapping->host)->root->fs_info,
2472 "partial page write in btrfs with offset %u and length %u",
2473 bvec->bv_offset, bvec->bv_len);
2474 else
2475 btrfs_info(BTRFS_I(page->mapping->host)->root->fs_info,
2476 "incomplete page write in btrfs with offset %u and "
2477 "length %u",
2478 bvec->bv_offset, bvec->bv_len);
2479 }
2480
2481 start = page_offset(page);
2482 end = start + bvec->bv_offset + bvec->bv_len - 1;
2483
2484 end_extent_writepage(page, bio->bi_error, start, end);
2485 end_page_writeback(page);
2486 }
2487
2488 bio_put(bio);
2489}
2490
2491static void
2492endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
2493 int uptodate)
2494{
2495 struct extent_state *cached = NULL;
2496 u64 end = start + len - 1;
2497
2498 if (uptodate && tree->track_uptodate)
2499 set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
2500 unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
2501}
2502
2503/*
2504 * after a readpage IO is done, we need to:
2505 * clear the uptodate bits on error
2506 * set the uptodate bits if things worked
2507 * set the page up to date if all extents in the tree are uptodate
2508 * clear the lock bit in the extent tree
2509 * unlock the page if there are no other extents locked for it
2510 *
2511 * Scheduling is not allowed, so the extent state tree is expected
2512 * to have one and only one object corresponding to this IO.
2513 */
2514static void end_bio_extent_readpage(struct bio *bio)
2515{
2516 struct bio_vec *bvec;
2517 int uptodate = !bio->bi_error;
2518 struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2519 struct extent_io_tree *tree;
2520 u64 offset = 0;
2521 u64 start;
2522 u64 end;
2523 u64 len;
2524 u64 extent_start = 0;
2525 u64 extent_len = 0;
2526 int mirror;
2527 int ret;
2528 int i;
2529
2530 bio_for_each_segment_all(bvec, bio, i) {
2531 struct page *page = bvec->bv_page;
2532 struct inode *inode = page->mapping->host;
2533
2534 pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
2535 "mirror=%u\n", (u64)bio->bi_iter.bi_sector,
2536 bio->bi_error, io_bio->mirror_num);
2537 tree = &BTRFS_I(inode)->io_tree;
2538
2539 /* We always issue full-page reads, but if some block
2540 * in a page fails to read, blk_update_request() will
2541 * advance bv_offset and adjust bv_len to compensate.
2542 * Print a warning for nonzero offsets, and an error
2543 * if they don't add up to a full page. */
2544 if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2545 if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2546 btrfs_err(BTRFS_I(page->mapping->host)->root->fs_info,
2547 "partial page read in btrfs with offset %u and length %u",
2548 bvec->bv_offset, bvec->bv_len);
2549 else
2550 btrfs_info(BTRFS_I(page->mapping->host)->root->fs_info,
2551 "incomplete page read in btrfs with offset %u and "
2552 "length %u",
2553 bvec->bv_offset, bvec->bv_len);
2554 }
2555
2556 start = page_offset(page);
2557 end = start + bvec->bv_offset + bvec->bv_len - 1;
2558 len = bvec->bv_len;
2559
2560 mirror = io_bio->mirror_num;
2561 if (likely(uptodate && tree->ops &&
2562 tree->ops->readpage_end_io_hook)) {
2563 ret = tree->ops->readpage_end_io_hook(io_bio, offset,
2564 page, start, end,
2565 mirror);
2566 if (ret)
2567 uptodate = 0;
2568 else
2569 clean_io_failure(inode, start, page, 0);
2570 }
2571
2572 if (likely(uptodate))
2573 goto readpage_ok;
2574
2575 if (tree->ops && tree->ops->readpage_io_failed_hook) {
2576 ret = tree->ops->readpage_io_failed_hook(page, mirror);
2577 if (!ret && !bio->bi_error)
2578 uptodate = 1;
2579 } else {
2580 /*
2581 * The generic bio_readpage_error handles errors the
2582 * following way: If possible, new read requests are
2583 * created and submitted and will end up in
2584 * end_bio_extent_readpage as well (if we're lucky, not
2585 * in the !uptodate case). In that case it returns 0 and
2586 * we just go on with the next page in our bio. If it
2587 * can't handle the error it will return -EIO and we
2588 * remain responsible for that page.
2589 */
2590 ret = bio_readpage_error(bio, offset, page, start, end,
2591 mirror);
2592 if (ret == 0) {
2593 uptodate = !bio->bi_error;
2594 offset += len;
2595 continue;
2596 }
2597 }
2598readpage_ok:
2599 if (likely(uptodate)) {
2600 loff_t i_size = i_size_read(inode);
2601 pgoff_t end_index = i_size >> PAGE_SHIFT;
2602 unsigned off;
2603
2604 /* Zero out the end if this page straddles i_size */
2605 off = i_size & (PAGE_SIZE-1);
2606 if (page->index == end_index && off)
2607 zero_user_segment(page, off, PAGE_SIZE);
2608 SetPageUptodate(page);
2609 } else {
2610 ClearPageUptodate(page);
2611 SetPageError(page);
2612 }
2613 unlock_page(page);
2614 offset += len;
2615
2616 if (unlikely(!uptodate)) {
2617 if (extent_len) {
2618 endio_readpage_release_extent(tree,
2619 extent_start,
2620 extent_len, 1);
2621 extent_start = 0;
2622 extent_len = 0;
2623 }
2624 endio_readpage_release_extent(tree, start,
2625 end - start + 1, 0);
2626 } else if (!extent_len) {
2627 extent_start = start;
2628 extent_len = end + 1 - start;
2629 } else if (extent_start + extent_len == start) {
2630 extent_len += end + 1 - start;
2631 } else {
2632 endio_readpage_release_extent(tree, extent_start,
2633 extent_len, uptodate);
2634 extent_start = start;
2635 extent_len = end + 1 - start;
2636 }
2637 }
2638
2639 if (extent_len)
2640 endio_readpage_release_extent(tree, extent_start, extent_len,
2641 uptodate);
2642 if (io_bio->end_io)
2643 io_bio->end_io(io_bio, bio->bi_error);
2644 bio_put(bio);
2645}
2646
2647/*
2648 * this allocates from the btrfs_bioset. We're returning a bio right now
2649 * but you can call btrfs_io_bio for the appropriate container_of magic
2650 */
2651struct bio *
2652btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
2653 gfp_t gfp_flags)
2654{
2655 struct btrfs_io_bio *btrfs_bio;
2656 struct bio *bio;
2657
2658 bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
2659
2660 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2661 while (!bio && (nr_vecs /= 2)) {
2662 bio = bio_alloc_bioset(gfp_flags,
2663 nr_vecs, btrfs_bioset);
2664 }
2665 }
2666
2667 if (bio) {
2668 bio->bi_bdev = bdev;
2669 bio->bi_iter.bi_sector = first_sector;
2670 btrfs_bio = btrfs_io_bio(bio);
2671 btrfs_bio->csum = NULL;
2672 btrfs_bio->csum_allocated = NULL;
2673 btrfs_bio->end_io = NULL;
2674 }
2675 return bio;
2676}
2677
2678struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
2679{
2680 struct btrfs_io_bio *btrfs_bio;
2681 struct bio *new;
2682
2683 new = bio_clone_bioset(bio, gfp_mask, btrfs_bioset);
2684 if (new) {
2685 btrfs_bio = btrfs_io_bio(new);
2686 btrfs_bio->csum = NULL;
2687 btrfs_bio->csum_allocated = NULL;
2688 btrfs_bio->end_io = NULL;
2689
2690#ifdef CONFIG_BLK_CGROUP
2691 /* FIXME, put this into bio_clone_bioset */
2692 if (bio->bi_css)
2693 bio_associate_blkcg(new, bio->bi_css);
2694#endif
2695 }
2696 return new;
2697}
2698
2699/* this also allocates from the btrfs_bioset */
2700struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
2701{
2702 struct btrfs_io_bio *btrfs_bio;
2703 struct bio *bio;
2704
2705 bio = bio_alloc_bioset(gfp_mask, nr_iovecs, btrfs_bioset);
2706 if (bio) {
2707 btrfs_bio = btrfs_io_bio(bio);
2708 btrfs_bio->csum = NULL;
2709 btrfs_bio->csum_allocated = NULL;
2710 btrfs_bio->end_io = NULL;
2711 }
2712 return bio;
2713}
2714
2715
2716static int __must_check submit_one_bio(int rw, struct bio *bio,
2717 int mirror_num, unsigned long bio_flags)
2718{
2719 int ret = 0;
2720 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
2721 struct page *page = bvec->bv_page;
2722 struct extent_io_tree *tree = bio->bi_private;
2723 u64 start;
2724
2725 start = page_offset(page) + bvec->bv_offset;
2726
2727 bio->bi_private = NULL;
2728
2729 bio_get(bio);
2730
2731 if (tree->ops && tree->ops->submit_bio_hook)
2732 ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
2733 mirror_num, bio_flags, start);
2734 else
2735 btrfsic_submit_bio(rw, bio);
2736
2737 bio_put(bio);
2738 return ret;
2739}
2740
2741static int merge_bio(int rw, struct extent_io_tree *tree, struct page *page,
2742 unsigned long offset, size_t size, struct bio *bio,
2743 unsigned long bio_flags)
2744{
2745 int ret = 0;
2746 if (tree->ops && tree->ops->merge_bio_hook)
2747 ret = tree->ops->merge_bio_hook(rw, page, offset, size, bio,
2748 bio_flags);
2749 BUG_ON(ret < 0);
2750 return ret;
2751
2752}
2753
2754static int submit_extent_page(int rw, struct extent_io_tree *tree,
2755 struct writeback_control *wbc,
2756 struct page *page, sector_t sector,
2757 size_t size, unsigned long offset,
2758 struct block_device *bdev,
2759 struct bio **bio_ret,
2760 unsigned long max_pages,
2761 bio_end_io_t end_io_func,
2762 int mirror_num,
2763 unsigned long prev_bio_flags,
2764 unsigned long bio_flags,
2765 bool force_bio_submit)
2766{
2767 int ret = 0;
2768 struct bio *bio;
2769 int contig = 0;
2770 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2771 size_t page_size = min_t(size_t, size, PAGE_SIZE);
2772
2773 if (bio_ret && *bio_ret) {
2774 bio = *bio_ret;
2775 if (old_compressed)
2776 contig = bio->bi_iter.bi_sector == sector;
2777 else
2778 contig = bio_end_sector(bio) == sector;
2779
2780 if (prev_bio_flags != bio_flags || !contig ||
2781 force_bio_submit ||
2782 merge_bio(rw, tree, page, offset, page_size, bio, bio_flags) ||
2783 bio_add_page(bio, page, page_size, offset) < page_size) {
2784 ret = submit_one_bio(rw, bio, mirror_num,
2785 prev_bio_flags);
2786 if (ret < 0) {
2787 *bio_ret = NULL;
2788 return ret;
2789 }
2790 bio = NULL;
2791 } else {
2792 if (wbc)
2793 wbc_account_io(wbc, page, page_size);
2794 return 0;
2795 }
2796 }
2797
2798 bio = btrfs_bio_alloc(bdev, sector, BIO_MAX_PAGES,
2799 GFP_NOFS | __GFP_HIGH);
2800 if (!bio)
2801 return -ENOMEM;
2802
2803 bio_add_page(bio, page, page_size, offset);
2804 bio->bi_end_io = end_io_func;
2805 bio->bi_private = tree;
2806 if (wbc) {
2807 wbc_init_bio(wbc, bio);
2808 wbc_account_io(wbc, page, page_size);
2809 }
2810
2811 if (bio_ret)
2812 *bio_ret = bio;
2813 else
2814 ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
2815
2816 return ret;
2817}
2818
2819static void attach_extent_buffer_page(struct extent_buffer *eb,
2820 struct page *page)
2821{
2822 if (!PagePrivate(page)) {
2823 SetPagePrivate(page);
2824 get_page(page);
2825 set_page_private(page, (unsigned long)eb);
2826 } else {
2827 WARN_ON(page->private != (unsigned long)eb);
2828 }
2829}
2830
2831void set_page_extent_mapped(struct page *page)
2832{
2833 if (!PagePrivate(page)) {
2834 SetPagePrivate(page);
2835 get_page(page);
2836 set_page_private(page, EXTENT_PAGE_PRIVATE);
2837 }
2838}
2839
2840static struct extent_map *
2841__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
2842 u64 start, u64 len, get_extent_t *get_extent,
2843 struct extent_map **em_cached)
2844{
2845 struct extent_map *em;
2846
2847 if (em_cached && *em_cached) {
2848 em = *em_cached;
2849 if (extent_map_in_tree(em) && start >= em->start &&
2850 start < extent_map_end(em)) {
2851 atomic_inc(&em->refs);
2852 return em;
2853 }
2854
2855 free_extent_map(em);
2856 *em_cached = NULL;
2857 }
2858
2859 em = get_extent(inode, page, pg_offset, start, len, 0);
2860 if (em_cached && !IS_ERR_OR_NULL(em)) {
2861 BUG_ON(*em_cached);
2862 atomic_inc(&em->refs);
2863 *em_cached = em;
2864 }
2865 return em;
2866}
2867/*
2868 * basic readpage implementation. Locked extent state structs are inserted
2869 * into the tree that are removed when the IO is done (by the end_io
2870 * handlers)
2871 * XXX JDM: This needs looking at to ensure proper page locking
2872 */
2873static int __do_readpage(struct extent_io_tree *tree,
2874 struct page *page,
2875 get_extent_t *get_extent,
2876 struct extent_map **em_cached,
2877 struct bio **bio, int mirror_num,
2878 unsigned long *bio_flags, int rw,
2879 u64 *prev_em_start)
2880{
2881 struct inode *inode = page->mapping->host;
2882 u64 start = page_offset(page);
2883 u64 page_end = start + PAGE_SIZE - 1;
2884 u64 end;
2885 u64 cur = start;
2886 u64 extent_offset;
2887 u64 last_byte = i_size_read(inode);
2888 u64 block_start;
2889 u64 cur_end;
2890 sector_t sector;
2891 struct extent_map *em;
2892 struct block_device *bdev;
2893 int ret;
2894 int nr = 0;
2895 size_t pg_offset = 0;
2896 size_t iosize;
2897 size_t disk_io_size;
2898 size_t blocksize = inode->i_sb->s_blocksize;
2899 unsigned long this_bio_flag = 0;
2900
2901 set_page_extent_mapped(page);
2902
2903 end = page_end;
2904 if (!PageUptodate(page)) {
2905 if (cleancache_get_page(page) == 0) {
2906 BUG_ON(blocksize != PAGE_SIZE);
2907 unlock_extent(tree, start, end);
2908 goto out;
2909 }
2910 }
2911
2912 if (page->index == last_byte >> PAGE_SHIFT) {
2913 char *userpage;
2914 size_t zero_offset = last_byte & (PAGE_SIZE - 1);
2915
2916 if (zero_offset) {
2917 iosize = PAGE_SIZE - zero_offset;
2918 userpage = kmap_atomic(page);
2919 memset(userpage + zero_offset, 0, iosize);
2920 flush_dcache_page(page);
2921 kunmap_atomic(userpage);
2922 }
2923 }
2924 while (cur <= end) {
2925 unsigned long pnr = (last_byte >> PAGE_SHIFT) + 1;
2926 bool force_bio_submit = false;
2927
2928 if (cur >= last_byte) {
2929 char *userpage;
2930 struct extent_state *cached = NULL;
2931
2932 iosize = PAGE_SIZE - pg_offset;
2933 userpage = kmap_atomic(page);
2934 memset(userpage + pg_offset, 0, iosize);
2935 flush_dcache_page(page);
2936 kunmap_atomic(userpage);
2937 set_extent_uptodate(tree, cur, cur + iosize - 1,
2938 &cached, GFP_NOFS);
2939 unlock_extent_cached(tree, cur,
2940 cur + iosize - 1,
2941 &cached, GFP_NOFS);
2942 break;
2943 }
2944 em = __get_extent_map(inode, page, pg_offset, cur,
2945 end - cur + 1, get_extent, em_cached);
2946 if (IS_ERR_OR_NULL(em)) {
2947 SetPageError(page);
2948 unlock_extent(tree, cur, end);
2949 break;
2950 }
2951 extent_offset = cur - em->start;
2952 BUG_ON(extent_map_end(em) <= cur);
2953 BUG_ON(end < cur);
2954
2955 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2956 this_bio_flag |= EXTENT_BIO_COMPRESSED;
2957 extent_set_compress_type(&this_bio_flag,
2958 em->compress_type);
2959 }
2960
2961 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2962 cur_end = min(extent_map_end(em) - 1, end);
2963 iosize = ALIGN(iosize, blocksize);
2964 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
2965 disk_io_size = em->block_len;
2966 sector = em->block_start >> 9;
2967 } else {
2968 sector = (em->block_start + extent_offset) >> 9;
2969 disk_io_size = iosize;
2970 }
2971 bdev = em->bdev;
2972 block_start = em->block_start;
2973 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2974 block_start = EXTENT_MAP_HOLE;
2975
2976 /*
2977 * If we have a file range that points to a compressed extent
2978 * and it's followed by a consecutive file range that points to
2979 * to the same compressed extent (possibly with a different
2980 * offset and/or length, so it either points to the whole extent
2981 * or only part of it), we must make sure we do not submit a
2982 * single bio to populate the pages for the 2 ranges because
2983 * this makes the compressed extent read zero out the pages
2984 * belonging to the 2nd range. Imagine the following scenario:
2985 *
2986 * File layout
2987 * [0 - 8K] [8K - 24K]
2988 * | |
2989 * | |
2990 * points to extent X, points to extent X,
2991 * offset 4K, length of 8K offset 0, length 16K
2992 *
2993 * [extent X, compressed length = 4K uncompressed length = 16K]
2994 *
2995 * If the bio to read the compressed extent covers both ranges,
2996 * it will decompress extent X into the pages belonging to the
2997 * first range and then it will stop, zeroing out the remaining
2998 * pages that belong to the other range that points to extent X.
2999 * So here we make sure we submit 2 bios, one for the first
3000 * range and another one for the third range. Both will target
3001 * the same physical extent from disk, but we can't currently
3002 * make the compressed bio endio callback populate the pages
3003 * for both ranges because each compressed bio is tightly
3004 * coupled with a single extent map, and each range can have
3005 * an extent map with a different offset value relative to the
3006 * uncompressed data of our extent and different lengths. This
3007 * is a corner case so we prioritize correctness over
3008 * non-optimal behavior (submitting 2 bios for the same extent).
3009 */
3010 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
3011 prev_em_start && *prev_em_start != (u64)-1 &&
3012 *prev_em_start != em->orig_start)
3013 force_bio_submit = true;
3014
3015 if (prev_em_start)
3016 *prev_em_start = em->orig_start;
3017
3018 free_extent_map(em);
3019 em = NULL;
3020
3021 /* we've found a hole, just zero and go on */
3022 if (block_start == EXTENT_MAP_HOLE) {
3023 char *userpage;
3024 struct extent_state *cached = NULL;
3025
3026 userpage = kmap_atomic(page);
3027 memset(userpage + pg_offset, 0, iosize);
3028 flush_dcache_page(page);
3029 kunmap_atomic(userpage);
3030
3031 set_extent_uptodate(tree, cur, cur + iosize - 1,
3032 &cached, GFP_NOFS);
3033 unlock_extent_cached(tree, cur,
3034 cur + iosize - 1,
3035 &cached, GFP_NOFS);
3036 cur = cur + iosize;
3037 pg_offset += iosize;
3038 continue;
3039 }
3040 /* the get_extent function already copied into the page */
3041 if (test_range_bit(tree, cur, cur_end,
3042 EXTENT_UPTODATE, 1, NULL)) {
3043 check_page_uptodate(tree, page);
3044 unlock_extent(tree, cur, cur + iosize - 1);
3045 cur = cur + iosize;
3046 pg_offset += iosize;
3047 continue;
3048 }
3049 /* we have an inline extent but it didn't get marked up
3050 * to date. Error out
3051 */
3052 if (block_start == EXTENT_MAP_INLINE) {
3053 SetPageError(page);
3054 unlock_extent(tree, cur, cur + iosize - 1);
3055 cur = cur + iosize;
3056 pg_offset += iosize;
3057 continue;
3058 }
3059
3060 pnr -= page->index;
3061 ret = submit_extent_page(rw, tree, NULL, page,
3062 sector, disk_io_size, pg_offset,
3063 bdev, bio, pnr,
3064 end_bio_extent_readpage, mirror_num,
3065 *bio_flags,
3066 this_bio_flag,
3067 force_bio_submit);
3068 if (!ret) {
3069 nr++;
3070 *bio_flags = this_bio_flag;
3071 } else {
3072 SetPageError(page);
3073 unlock_extent(tree, cur, cur + iosize - 1);
3074 }
3075 cur = cur + iosize;
3076 pg_offset += iosize;
3077 }
3078out:
3079 if (!nr) {
3080 if (!PageError(page))
3081 SetPageUptodate(page);
3082 unlock_page(page);
3083 }
3084 return 0;
3085}
3086
3087static inline void __do_contiguous_readpages(struct extent_io_tree *tree,
3088 struct page *pages[], int nr_pages,
3089 u64 start, u64 end,
3090 get_extent_t *get_extent,
3091 struct extent_map **em_cached,
3092 struct bio **bio, int mirror_num,
3093 unsigned long *bio_flags, int rw,
3094 u64 *prev_em_start)
3095{
3096 struct inode *inode;
3097 struct btrfs_ordered_extent *ordered;
3098 int index;
3099
3100 inode = pages[0]->mapping->host;
3101 while (1) {
3102 lock_extent(tree, start, end);
3103 ordered = btrfs_lookup_ordered_range(inode, start,
3104 end - start + 1);
3105 if (!ordered)
3106 break;
3107 unlock_extent(tree, start, end);
3108 btrfs_start_ordered_extent(inode, ordered, 1);
3109 btrfs_put_ordered_extent(ordered);
3110 }
3111
3112 for (index = 0; index < nr_pages; index++) {
3113 __do_readpage(tree, pages[index], get_extent, em_cached, bio,
3114 mirror_num, bio_flags, rw, prev_em_start);
3115 put_page(pages[index]);
3116 }
3117}
3118
3119static void __extent_readpages(struct extent_io_tree *tree,
3120 struct page *pages[],
3121 int nr_pages, get_extent_t *get_extent,
3122 struct extent_map **em_cached,
3123 struct bio **bio, int mirror_num,
3124 unsigned long *bio_flags, int rw,
3125 u64 *prev_em_start)
3126{
3127 u64 start = 0;
3128 u64 end = 0;
3129 u64 page_start;
3130 int index;
3131 int first_index = 0;
3132
3133 for (index = 0; index < nr_pages; index++) {
3134 page_start = page_offset(pages[index]);
3135 if (!end) {
3136 start = page_start;
3137 end = start + PAGE_SIZE - 1;
3138 first_index = index;
3139 } else if (end + 1 == page_start) {
3140 end += PAGE_SIZE;
3141 } else {
3142 __do_contiguous_readpages(tree, &pages[first_index],
3143 index - first_index, start,
3144 end, get_extent, em_cached,
3145 bio, mirror_num, bio_flags,
3146 rw, prev_em_start);
3147 start = page_start;
3148 end = start + PAGE_SIZE - 1;
3149 first_index = index;
3150 }
3151 }
3152
3153 if (end)
3154 __do_contiguous_readpages(tree, &pages[first_index],
3155 index - first_index, start,
3156 end, get_extent, em_cached, bio,
3157 mirror_num, bio_flags, rw,
3158 prev_em_start);
3159}
3160
3161static int __extent_read_full_page(struct extent_io_tree *tree,
3162 struct page *page,
3163 get_extent_t *get_extent,
3164 struct bio **bio, int mirror_num,
3165 unsigned long *bio_flags, int rw)
3166{
3167 struct inode *inode = page->mapping->host;
3168 struct btrfs_ordered_extent *ordered;
3169 u64 start = page_offset(page);
3170 u64 end = start + PAGE_SIZE - 1;
3171 int ret;
3172
3173 while (1) {
3174 lock_extent(tree, start, end);
3175 ordered = btrfs_lookup_ordered_range(inode, start,
3176 PAGE_SIZE);
3177 if (!ordered)
3178 break;
3179 unlock_extent(tree, start, end);
3180 btrfs_start_ordered_extent(inode, ordered, 1);
3181 btrfs_put_ordered_extent(ordered);
3182 }
3183
3184 ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
3185 bio_flags, rw, NULL);
3186 return ret;
3187}
3188
3189int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3190 get_extent_t *get_extent, int mirror_num)
3191{
3192 struct bio *bio = NULL;
3193 unsigned long bio_flags = 0;
3194 int ret;
3195
3196 ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3197 &bio_flags, READ);
3198 if (bio)
3199 ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
3200 return ret;
3201}
3202
3203static noinline void update_nr_written(struct page *page,
3204 struct writeback_control *wbc,
3205 unsigned long nr_written)
3206{
3207 wbc->nr_to_write -= nr_written;
3208 if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
3209 wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
3210 page->mapping->writeback_index = page->index + nr_written;
3211}
3212
3213/*
3214 * helper for __extent_writepage, doing all of the delayed allocation setup.
3215 *
3216 * This returns 1 if our fill_delalloc function did all the work required
3217 * to write the page (copy into inline extent). In this case the IO has
3218 * been started and the page is already unlocked.
3219 *
3220 * This returns 0 if all went well (page still locked)
3221 * This returns < 0 if there were errors (page still locked)
3222 */
3223static noinline_for_stack int writepage_delalloc(struct inode *inode,
3224 struct page *page, struct writeback_control *wbc,
3225 struct extent_page_data *epd,
3226 u64 delalloc_start,
3227 unsigned long *nr_written)
3228{
3229 struct extent_io_tree *tree = epd->tree;
3230 u64 page_end = delalloc_start + PAGE_SIZE - 1;
3231 u64 nr_delalloc;
3232 u64 delalloc_to_write = 0;
3233 u64 delalloc_end = 0;
3234 int ret;
3235 int page_started = 0;
3236
3237 if (epd->extent_locked || !tree->ops || !tree->ops->fill_delalloc)
3238 return 0;
3239
3240 while (delalloc_end < page_end) {
3241 nr_delalloc = find_lock_delalloc_range(inode, tree,
3242 page,
3243 &delalloc_start,
3244 &delalloc_end,
3245 BTRFS_MAX_EXTENT_SIZE);
3246 if (nr_delalloc == 0) {
3247 delalloc_start = delalloc_end + 1;
3248 continue;
3249 }
3250 ret = tree->ops->fill_delalloc(inode, page,
3251 delalloc_start,
3252 delalloc_end,
3253 &page_started,
3254 nr_written);
3255 /* File system has been set read-only */
3256 if (ret) {
3257 SetPageError(page);
3258 /* fill_delalloc should be return < 0 for error
3259 * but just in case, we use > 0 here meaning the
3260 * IO is started, so we don't want to return > 0
3261 * unless things are going well.
3262 */
3263 ret = ret < 0 ? ret : -EIO;
3264 goto done;
3265 }
3266 /*
3267 * delalloc_end is already one less than the total length, so
3268 * we don't subtract one from PAGE_SIZE
3269 */
3270 delalloc_to_write += (delalloc_end - delalloc_start +
3271 PAGE_SIZE) >> PAGE_SHIFT;
3272 delalloc_start = delalloc_end + 1;
3273 }
3274 if (wbc->nr_to_write < delalloc_to_write) {
3275 int thresh = 8192;
3276
3277 if (delalloc_to_write < thresh * 2)
3278 thresh = delalloc_to_write;
3279 wbc->nr_to_write = min_t(u64, delalloc_to_write,
3280 thresh);
3281 }
3282
3283 /* did the fill delalloc function already unlock and start
3284 * the IO?
3285 */
3286 if (page_started) {
3287 /*
3288 * we've unlocked the page, so we can't update
3289 * the mapping's writeback index, just update
3290 * nr_to_write.
3291 */
3292 wbc->nr_to_write -= *nr_written;
3293 return 1;
3294 }
3295
3296 ret = 0;
3297
3298done:
3299 return ret;
3300}
3301
3302/*
3303 * helper for __extent_writepage. This calls the writepage start hooks,
3304 * and does the loop to map the page into extents and bios.
3305 *
3306 * We return 1 if the IO is started and the page is unlocked,
3307 * 0 if all went well (page still locked)
3308 * < 0 if there were errors (page still locked)
3309 */
3310static noinline_for_stack int __extent_writepage_io(struct inode *inode,
3311 struct page *page,
3312 struct writeback_control *wbc,
3313 struct extent_page_data *epd,
3314 loff_t i_size,
3315 unsigned long nr_written,
3316 int write_flags, int *nr_ret)
3317{
3318 struct extent_io_tree *tree = epd->tree;
3319 u64 start = page_offset(page);
3320 u64 page_end = start + PAGE_SIZE - 1;
3321 u64 end;
3322 u64 cur = start;
3323 u64 extent_offset;
3324 u64 block_start;
3325 u64 iosize;
3326 sector_t sector;
3327 struct extent_state *cached_state = NULL;
3328 struct extent_map *em;
3329 struct block_device *bdev;
3330 size_t pg_offset = 0;
3331 size_t blocksize;
3332 int ret = 0;
3333 int nr = 0;
3334 bool compressed;
3335
3336 if (tree->ops && tree->ops->writepage_start_hook) {
3337 ret = tree->ops->writepage_start_hook(page, start,
3338 page_end);
3339 if (ret) {
3340 /* Fixup worker will requeue */
3341 if (ret == -EBUSY)
3342 wbc->pages_skipped++;
3343 else
3344 redirty_page_for_writepage(wbc, page);
3345
3346 update_nr_written(page, wbc, nr_written);
3347 unlock_page(page);
3348 ret = 1;
3349 goto done_unlocked;
3350 }
3351 }
3352
3353 /*
3354 * we don't want to touch the inode after unlocking the page,
3355 * so we update the mapping writeback index now
3356 */
3357 update_nr_written(page, wbc, nr_written + 1);
3358
3359 end = page_end;
3360 if (i_size <= start) {
3361 if (tree->ops && tree->ops->writepage_end_io_hook)
3362 tree->ops->writepage_end_io_hook(page, start,
3363 page_end, NULL, 1);
3364 goto done;
3365 }
3366
3367 blocksize = inode->i_sb->s_blocksize;
3368
3369 while (cur <= end) {
3370 u64 em_end;
3371 if (cur >= i_size) {
3372 if (tree->ops && tree->ops->writepage_end_io_hook)
3373 tree->ops->writepage_end_io_hook(page, cur,
3374 page_end, NULL, 1);
3375 break;
3376 }
3377 em = epd->get_extent(inode, page, pg_offset, cur,
3378 end - cur + 1, 1);
3379 if (IS_ERR_OR_NULL(em)) {
3380 SetPageError(page);
3381 ret = PTR_ERR_OR_ZERO(em);
3382 break;
3383 }
3384
3385 extent_offset = cur - em->start;
3386 em_end = extent_map_end(em);
3387 BUG_ON(em_end <= cur);
3388 BUG_ON(end < cur);
3389 iosize = min(em_end - cur, end - cur + 1);
3390 iosize = ALIGN(iosize, blocksize);
3391 sector = (em->block_start + extent_offset) >> 9;
3392 bdev = em->bdev;
3393 block_start = em->block_start;
3394 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3395 free_extent_map(em);
3396 em = NULL;
3397
3398 /*
3399 * compressed and inline extents are written through other
3400 * paths in the FS
3401 */
3402 if (compressed || block_start == EXTENT_MAP_HOLE ||
3403 block_start == EXTENT_MAP_INLINE) {
3404 /*
3405 * end_io notification does not happen here for
3406 * compressed extents
3407 */
3408 if (!compressed && tree->ops &&
3409 tree->ops->writepage_end_io_hook)
3410 tree->ops->writepage_end_io_hook(page, cur,
3411 cur + iosize - 1,
3412 NULL, 1);
3413 else if (compressed) {
3414 /* we don't want to end_page_writeback on
3415 * a compressed extent. this happens
3416 * elsewhere
3417 */
3418 nr++;
3419 }
3420
3421 cur += iosize;
3422 pg_offset += iosize;
3423 continue;
3424 }
3425
3426 if (tree->ops && tree->ops->writepage_io_hook) {
3427 ret = tree->ops->writepage_io_hook(page, cur,
3428 cur + iosize - 1);
3429 } else {
3430 ret = 0;
3431 }
3432 if (ret) {
3433 SetPageError(page);
3434 } else {
3435 unsigned long max_nr = (i_size >> PAGE_SHIFT) + 1;
3436
3437 set_range_writeback(tree, cur, cur + iosize - 1);
3438 if (!PageWriteback(page)) {
3439 btrfs_err(BTRFS_I(inode)->root->fs_info,
3440 "page %lu not writeback, cur %llu end %llu",
3441 page->index, cur, end);
3442 }
3443
3444 ret = submit_extent_page(write_flags, tree, wbc, page,
3445 sector, iosize, pg_offset,
3446 bdev, &epd->bio, max_nr,
3447 end_bio_extent_writepage,
3448 0, 0, 0, false);
3449 if (ret)
3450 SetPageError(page);
3451 }
3452 cur = cur + iosize;
3453 pg_offset += iosize;
3454 nr++;
3455 }
3456done:
3457 *nr_ret = nr;
3458
3459done_unlocked:
3460
3461 /* drop our reference on any cached states */
3462 free_extent_state(cached_state);
3463 return ret;
3464}
3465
3466/*
3467 * the writepage semantics are similar to regular writepage. extent
3468 * records are inserted to lock ranges in the tree, and as dirty areas
3469 * are found, they are marked writeback. Then the lock bits are removed
3470 * and the end_io handler clears the writeback ranges
3471 */
3472static int __extent_writepage(struct page *page, struct writeback_control *wbc,
3473 void *data)
3474{
3475 struct inode *inode = page->mapping->host;
3476 struct extent_page_data *epd = data;
3477 u64 start = page_offset(page);
3478 u64 page_end = start + PAGE_SIZE - 1;
3479 int ret;
3480 int nr = 0;
3481 size_t pg_offset = 0;
3482 loff_t i_size = i_size_read(inode);
3483 unsigned long end_index = i_size >> PAGE_SHIFT;
3484 int write_flags;
3485 unsigned long nr_written = 0;
3486
3487 if (wbc->sync_mode == WB_SYNC_ALL)
3488 write_flags = WRITE_SYNC;
3489 else
3490 write_flags = WRITE;
3491
3492 trace___extent_writepage(page, inode, wbc);
3493
3494 WARN_ON(!PageLocked(page));
3495
3496 ClearPageError(page);
3497
3498 pg_offset = i_size & (PAGE_SIZE - 1);
3499 if (page->index > end_index ||
3500 (page->index == end_index && !pg_offset)) {
3501 page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
3502 unlock_page(page);
3503 return 0;
3504 }
3505
3506 if (page->index == end_index) {
3507 char *userpage;
3508
3509 userpage = kmap_atomic(page);
3510 memset(userpage + pg_offset, 0,
3511 PAGE_SIZE - pg_offset);
3512 kunmap_atomic(userpage);
3513 flush_dcache_page(page);
3514 }
3515
3516 pg_offset = 0;
3517
3518 set_page_extent_mapped(page);
3519
3520 ret = writepage_delalloc(inode, page, wbc, epd, start, &nr_written);
3521 if (ret == 1)
3522 goto done_unlocked;
3523 if (ret)
3524 goto done;
3525
3526 ret = __extent_writepage_io(inode, page, wbc, epd,
3527 i_size, nr_written, write_flags, &nr);
3528 if (ret == 1)
3529 goto done_unlocked;
3530
3531done:
3532 if (nr == 0) {
3533 /* make sure the mapping tag for page dirty gets cleared */
3534 set_page_writeback(page);
3535 end_page_writeback(page);
3536 }
3537 if (PageError(page)) {
3538 ret = ret < 0 ? ret : -EIO;
3539 end_extent_writepage(page, ret, start, page_end);
3540 }
3541 unlock_page(page);
3542 return ret;
3543
3544done_unlocked:
3545 return 0;
3546}
3547
3548void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3549{
3550 wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
3551 TASK_UNINTERRUPTIBLE);
3552}
3553
3554static noinline_for_stack int
3555lock_extent_buffer_for_io(struct extent_buffer *eb,
3556 struct btrfs_fs_info *fs_info,
3557 struct extent_page_data *epd)
3558{
3559 unsigned long i, num_pages;
3560 int flush = 0;
3561 int ret = 0;
3562
3563 if (!btrfs_try_tree_write_lock(eb)) {
3564 flush = 1;
3565 flush_write_bio(epd);
3566 btrfs_tree_lock(eb);
3567 }
3568
3569 if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
3570 btrfs_tree_unlock(eb);
3571 if (!epd->sync_io)
3572 return 0;
3573 if (!flush) {
3574 flush_write_bio(epd);
3575 flush = 1;
3576 }
3577 while (1) {
3578 wait_on_extent_buffer_writeback(eb);
3579 btrfs_tree_lock(eb);
3580 if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
3581 break;
3582 btrfs_tree_unlock(eb);
3583 }
3584 }
3585
3586 /*
3587 * We need to do this to prevent races in people who check if the eb is
3588 * under IO since we can end up having no IO bits set for a short period
3589 * of time.
3590 */
3591 spin_lock(&eb->refs_lock);
3592 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3593 set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3594 spin_unlock(&eb->refs_lock);
3595 btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3596 __percpu_counter_add(&fs_info->dirty_metadata_bytes,
3597 -eb->len,
3598 fs_info->dirty_metadata_batch);
3599 ret = 1;
3600 } else {
3601 spin_unlock(&eb->refs_lock);
3602 }
3603
3604 btrfs_tree_unlock(eb);
3605
3606 if (!ret)
3607 return ret;
3608
3609 num_pages = num_extent_pages(eb->start, eb->len);
3610 for (i = 0; i < num_pages; i++) {
3611 struct page *p = eb->pages[i];
3612
3613 if (!trylock_page(p)) {
3614 if (!flush) {
3615 flush_write_bio(epd);
3616 flush = 1;
3617 }
3618 lock_page(p);
3619 }
3620 }
3621
3622 return ret;
3623}
3624
3625static void end_extent_buffer_writeback(struct extent_buffer *eb)
3626{
3627 clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3628 smp_mb__after_atomic();
3629 wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
3630}
3631
3632static void set_btree_ioerr(struct page *page)
3633{
3634 struct extent_buffer *eb = (struct extent_buffer *)page->private;
3635 struct btrfs_inode *btree_ino = BTRFS_I(eb->fs_info->btree_inode);
3636
3637 SetPageError(page);
3638 if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
3639 return;
3640
3641 /*
3642 * If writeback for a btree extent that doesn't belong to a log tree
3643 * failed, increment the counter transaction->eb_write_errors.
3644 * We do this because while the transaction is running and before it's
3645 * committing (when we call filemap_fdata[write|wait]_range against
3646 * the btree inode), we might have
3647 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
3648 * returns an error or an error happens during writeback, when we're
3649 * committing the transaction we wouldn't know about it, since the pages
3650 * can be no longer dirty nor marked anymore for writeback (if a
3651 * subsequent modification to the extent buffer didn't happen before the
3652 * transaction commit), which makes filemap_fdata[write|wait]_range not
3653 * able to find the pages tagged with SetPageError at transaction
3654 * commit time. So if this happens we must abort the transaction,
3655 * otherwise we commit a super block with btree roots that point to
3656 * btree nodes/leafs whose content on disk is invalid - either garbage
3657 * or the content of some node/leaf from a past generation that got
3658 * cowed or deleted and is no longer valid.
3659 *
3660 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
3661 * not be enough - we need to distinguish between log tree extents vs
3662 * non-log tree extents, and the next filemap_fdatawait_range() call
3663 * will catch and clear such errors in the mapping - and that call might
3664 * be from a log sync and not from a transaction commit. Also, checking
3665 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
3666 * not done and would not be reliable - the eb might have been released
3667 * from memory and reading it back again means that flag would not be
3668 * set (since it's a runtime flag, not persisted on disk).
3669 *
3670 * Using the flags below in the btree inode also makes us achieve the
3671 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
3672 * writeback for all dirty pages and before filemap_fdatawait_range()
3673 * is called, the writeback for all dirty pages had already finished
3674 * with errors - because we were not using AS_EIO/AS_ENOSPC,
3675 * filemap_fdatawait_range() would return success, as it could not know
3676 * that writeback errors happened (the pages were no longer tagged for
3677 * writeback).
3678 */
3679 switch (eb->log_index) {
3680 case -1:
3681 set_bit(BTRFS_INODE_BTREE_ERR, &btree_ino->runtime_flags);
3682 break;
3683 case 0:
3684 set_bit(BTRFS_INODE_BTREE_LOG1_ERR, &btree_ino->runtime_flags);
3685 break;
3686 case 1:
3687 set_bit(BTRFS_INODE_BTREE_LOG2_ERR, &btree_ino->runtime_flags);
3688 break;
3689 default:
3690 BUG(); /* unexpected, logic error */
3691 }
3692}
3693
3694static void end_bio_extent_buffer_writepage(struct bio *bio)
3695{
3696 struct bio_vec *bvec;
3697 struct extent_buffer *eb;
3698 int i, done;
3699
3700 bio_for_each_segment_all(bvec, bio, i) {
3701 struct page *page = bvec->bv_page;
3702
3703 eb = (struct extent_buffer *)page->private;
3704 BUG_ON(!eb);
3705 done = atomic_dec_and_test(&eb->io_pages);
3706
3707 if (bio->bi_error ||
3708 test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
3709 ClearPageUptodate(page);
3710 set_btree_ioerr(page);
3711 }
3712
3713 end_page_writeback(page);
3714
3715 if (!done)
3716 continue;
3717
3718 end_extent_buffer_writeback(eb);
3719 }
3720
3721 bio_put(bio);
3722}
3723
3724static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3725 struct btrfs_fs_info *fs_info,
3726 struct writeback_control *wbc,
3727 struct extent_page_data *epd)
3728{
3729 struct block_device *bdev = fs_info->fs_devices->latest_bdev;
3730 struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3731 u64 offset = eb->start;
3732 unsigned long i, num_pages;
3733 unsigned long bio_flags = 0;
3734 int rw = (epd->sync_io ? WRITE_SYNC : WRITE) | REQ_META;
3735 int ret = 0;
3736
3737 clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
3738 num_pages = num_extent_pages(eb->start, eb->len);
3739 atomic_set(&eb->io_pages, num_pages);
3740 if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
3741 bio_flags = EXTENT_BIO_TREE_LOG;
3742
3743 for (i = 0; i < num_pages; i++) {
3744 struct page *p = eb->pages[i];
3745
3746 clear_page_dirty_for_io(p);
3747 set_page_writeback(p);
3748 ret = submit_extent_page(rw, tree, wbc, p, offset >> 9,
3749 PAGE_SIZE, 0, bdev, &epd->bio,
3750 -1, end_bio_extent_buffer_writepage,
3751 0, epd->bio_flags, bio_flags, false);
3752 epd->bio_flags = bio_flags;
3753 if (ret) {
3754 set_btree_ioerr(p);
3755 end_page_writeback(p);
3756 if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
3757 end_extent_buffer_writeback(eb);
3758 ret = -EIO;
3759 break;
3760 }
3761 offset += PAGE_SIZE;
3762 update_nr_written(p, wbc, 1);
3763 unlock_page(p);
3764 }
3765
3766 if (unlikely(ret)) {
3767 for (; i < num_pages; i++) {
3768 struct page *p = eb->pages[i];
3769 clear_page_dirty_for_io(p);
3770 unlock_page(p);
3771 }
3772 }
3773
3774 return ret;
3775}
3776
3777int btree_write_cache_pages(struct address_space *mapping,
3778 struct writeback_control *wbc)
3779{
3780 struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
3781 struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
3782 struct extent_buffer *eb, *prev_eb = NULL;
3783 struct extent_page_data epd = {
3784 .bio = NULL,
3785 .tree = tree,
3786 .extent_locked = 0,
3787 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
3788 .bio_flags = 0,
3789 };
3790 int ret = 0;
3791 int done = 0;
3792 int nr_to_write_done = 0;
3793 struct pagevec pvec;
3794 int nr_pages;
3795 pgoff_t index;
3796 pgoff_t end; /* Inclusive */
3797 int scanned = 0;
3798 int tag;
3799
3800 pagevec_init(&pvec, 0);
3801 if (wbc->range_cyclic) {
3802 index = mapping->writeback_index; /* Start from prev offset */
3803 end = -1;
3804 } else {
3805 index = wbc->range_start >> PAGE_SHIFT;
3806 end = wbc->range_end >> PAGE_SHIFT;
3807 scanned = 1;
3808 }
3809 if (wbc->sync_mode == WB_SYNC_ALL)
3810 tag = PAGECACHE_TAG_TOWRITE;
3811 else
3812 tag = PAGECACHE_TAG_DIRTY;
3813retry:
3814 if (wbc->sync_mode == WB_SYNC_ALL)
3815 tag_pages_for_writeback(mapping, index, end);
3816 while (!done && !nr_to_write_done && (index <= end) &&
3817 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3818 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3819 unsigned i;
3820
3821 scanned = 1;
3822 for (i = 0; i < nr_pages; i++) {
3823 struct page *page = pvec.pages[i];
3824
3825 if (!PagePrivate(page))
3826 continue;
3827
3828 if (!wbc->range_cyclic && page->index > end) {
3829 done = 1;
3830 break;
3831 }
3832
3833 spin_lock(&mapping->private_lock);
3834 if (!PagePrivate(page)) {
3835 spin_unlock(&mapping->private_lock);
3836 continue;
3837 }
3838
3839 eb = (struct extent_buffer *)page->private;
3840
3841 /*
3842 * Shouldn't happen and normally this would be a BUG_ON
3843 * but no sense in crashing the users box for something
3844 * we can survive anyway.
3845 */
3846 if (WARN_ON(!eb)) {
3847 spin_unlock(&mapping->private_lock);
3848 continue;
3849 }
3850
3851 if (eb == prev_eb) {
3852 spin_unlock(&mapping->private_lock);
3853 continue;
3854 }
3855
3856 ret = atomic_inc_not_zero(&eb->refs);
3857 spin_unlock(&mapping->private_lock);
3858 if (!ret)
3859 continue;
3860
3861 prev_eb = eb;
3862 ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
3863 if (!ret) {
3864 free_extent_buffer(eb);
3865 continue;
3866 }
3867
3868 ret = write_one_eb(eb, fs_info, wbc, &epd);
3869 if (ret) {
3870 done = 1;
3871 free_extent_buffer(eb);
3872 break;
3873 }
3874 free_extent_buffer(eb);
3875
3876 /*
3877 * the filesystem may choose to bump up nr_to_write.
3878 * We have to make sure to honor the new nr_to_write
3879 * at any time
3880 */
3881 nr_to_write_done = wbc->nr_to_write <= 0;
3882 }
3883 pagevec_release(&pvec);
3884 cond_resched();
3885 }
3886 if (!scanned && !done) {
3887 /*
3888 * We hit the last page and there is more work to be done: wrap
3889 * back to the start of the file
3890 */
3891 scanned = 1;
3892 index = 0;
3893 goto retry;
3894 }
3895 flush_write_bio(&epd);
3896 return ret;
3897}
3898
3899/**
3900 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3901 * @mapping: address space structure to write
3902 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
3903 * @writepage: function called for each page
3904 * @data: data passed to writepage function
3905 *
3906 * If a page is already under I/O, write_cache_pages() skips it, even
3907 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
3908 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
3909 * and msync() need to guarantee that all the data which was dirty at the time
3910 * the call was made get new I/O started against them. If wbc->sync_mode is
3911 * WB_SYNC_ALL then we were called for data integrity and we must wait for
3912 * existing IO to complete.
3913 */
3914static int extent_write_cache_pages(struct extent_io_tree *tree,
3915 struct address_space *mapping,
3916 struct writeback_control *wbc,
3917 writepage_t writepage, void *data,
3918 void (*flush_fn)(void *))
3919{
3920 struct inode *inode = mapping->host;
3921 int ret = 0;
3922 int done = 0;
3923 int err = 0;
3924 int nr_to_write_done = 0;
3925 struct pagevec pvec;
3926 int nr_pages;
3927 pgoff_t index;
3928 pgoff_t end; /* Inclusive */
3929 int scanned = 0;
3930 int tag;
3931
3932 /*
3933 * We have to hold onto the inode so that ordered extents can do their
3934 * work when the IO finishes. The alternative to this is failing to add
3935 * an ordered extent if the igrab() fails there and that is a huge pain
3936 * to deal with, so instead just hold onto the inode throughout the
3937 * writepages operation. If it fails here we are freeing up the inode
3938 * anyway and we'd rather not waste our time writing out stuff that is
3939 * going to be truncated anyway.
3940 */
3941 if (!igrab(inode))
3942 return 0;
3943
3944 pagevec_init(&pvec, 0);
3945 if (wbc->range_cyclic) {
3946 index = mapping->writeback_index; /* Start from prev offset */
3947 end = -1;
3948 } else {
3949 index = wbc->range_start >> PAGE_SHIFT;
3950 end = wbc->range_end >> PAGE_SHIFT;
3951 scanned = 1;
3952 }
3953 if (wbc->sync_mode == WB_SYNC_ALL)
3954 tag = PAGECACHE_TAG_TOWRITE;
3955 else
3956 tag = PAGECACHE_TAG_DIRTY;
3957retry:
3958 if (wbc->sync_mode == WB_SYNC_ALL)
3959 tag_pages_for_writeback(mapping, index, end);
3960 while (!done && !nr_to_write_done && (index <= end) &&
3961 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3962 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3963 unsigned i;
3964
3965 scanned = 1;
3966 for (i = 0; i < nr_pages; i++) {
3967 struct page *page = pvec.pages[i];
3968
3969 /*
3970 * At this point we hold neither mapping->tree_lock nor
3971 * lock on the page itself: the page may be truncated or
3972 * invalidated (changing page->mapping to NULL), or even
3973 * swizzled back from swapper_space to tmpfs file
3974 * mapping
3975 */
3976 if (!trylock_page(page)) {
3977 flush_fn(data);
3978 lock_page(page);
3979 }
3980
3981 if (unlikely(page->mapping != mapping)) {
3982 unlock_page(page);
3983 continue;
3984 }
3985
3986 if (!wbc->range_cyclic && page->index > end) {
3987 done = 1;
3988 unlock_page(page);
3989 continue;
3990 }
3991
3992 if (wbc->sync_mode != WB_SYNC_NONE) {
3993 if (PageWriteback(page))
3994 flush_fn(data);
3995 wait_on_page_writeback(page);
3996 }
3997
3998 if (PageWriteback(page) ||
3999 !clear_page_dirty_for_io(page)) {
4000 unlock_page(page);
4001 continue;
4002 }
4003
4004 ret = (*writepage)(page, wbc, data);
4005
4006 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
4007 unlock_page(page);
4008 ret = 0;
4009 }
4010 if (!err && ret < 0)
4011 err = ret;
4012
4013 /*
4014 * the filesystem may choose to bump up nr_to_write.
4015 * We have to make sure to honor the new nr_to_write
4016 * at any time
4017 */
4018 nr_to_write_done = wbc->nr_to_write <= 0;
4019 }
4020 pagevec_release(&pvec);
4021 cond_resched();
4022 }
4023 if (!scanned && !done && !err) {
4024 /*
4025 * We hit the last page and there is more work to be done: wrap
4026 * back to the start of the file
4027 */
4028 scanned = 1;
4029 index = 0;
4030 goto retry;
4031 }
4032 btrfs_add_delayed_iput(inode);
4033 return err;
4034}
4035
4036static void flush_epd_write_bio(struct extent_page_data *epd)
4037{
4038 if (epd->bio) {
4039 int rw = WRITE;
4040 int ret;
4041
4042 if (epd->sync_io)
4043 rw = WRITE_SYNC;
4044
4045 ret = submit_one_bio(rw, epd->bio, 0, epd->bio_flags);
4046 BUG_ON(ret < 0); /* -ENOMEM */
4047 epd->bio = NULL;
4048 }
4049}
4050
4051static noinline void flush_write_bio(void *data)
4052{
4053 struct extent_page_data *epd = data;
4054 flush_epd_write_bio(epd);
4055}
4056
4057int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
4058 get_extent_t *get_extent,
4059 struct writeback_control *wbc)
4060{
4061 int ret;
4062 struct extent_page_data epd = {
4063 .bio = NULL,
4064 .tree = tree,
4065 .get_extent = get_extent,
4066 .extent_locked = 0,
4067 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4068 .bio_flags = 0,
4069 };
4070
4071 ret = __extent_writepage(page, wbc, &epd);
4072
4073 flush_epd_write_bio(&epd);
4074 return ret;
4075}
4076
4077int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
4078 u64 start, u64 end, get_extent_t *get_extent,
4079 int mode)
4080{
4081 int ret = 0;
4082 struct address_space *mapping = inode->i_mapping;
4083 struct page *page;
4084 unsigned long nr_pages = (end - start + PAGE_SIZE) >>
4085 PAGE_SHIFT;
4086
4087 struct extent_page_data epd = {
4088 .bio = NULL,
4089 .tree = tree,
4090 .get_extent = get_extent,
4091 .extent_locked = 1,
4092 .sync_io = mode == WB_SYNC_ALL,
4093 .bio_flags = 0,
4094 };
4095 struct writeback_control wbc_writepages = {
4096 .sync_mode = mode,
4097 .nr_to_write = nr_pages * 2,
4098 .range_start = start,
4099 .range_end = end + 1,
4100 };
4101
4102 while (start <= end) {
4103 page = find_get_page(mapping, start >> PAGE_SHIFT);
4104 if (clear_page_dirty_for_io(page))
4105 ret = __extent_writepage(page, &wbc_writepages, &epd);
4106 else {
4107 if (tree->ops && tree->ops->writepage_end_io_hook)
4108 tree->ops->writepage_end_io_hook(page, start,
4109 start + PAGE_SIZE - 1,
4110 NULL, 1);
4111 unlock_page(page);
4112 }
4113 put_page(page);
4114 start += PAGE_SIZE;
4115 }
4116
4117 flush_epd_write_bio(&epd);
4118 return ret;
4119}
4120
4121int extent_writepages(struct extent_io_tree *tree,
4122 struct address_space *mapping,
4123 get_extent_t *get_extent,
4124 struct writeback_control *wbc)
4125{
4126 int ret = 0;
4127 struct extent_page_data epd = {
4128 .bio = NULL,
4129 .tree = tree,
4130 .get_extent = get_extent,
4131 .extent_locked = 0,
4132 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4133 .bio_flags = 0,
4134 };
4135
4136 ret = extent_write_cache_pages(tree, mapping, wbc,
4137 __extent_writepage, &epd,
4138 flush_write_bio);
4139 flush_epd_write_bio(&epd);
4140 return ret;
4141}
4142
4143int extent_readpages(struct extent_io_tree *tree,
4144 struct address_space *mapping,
4145 struct list_head *pages, unsigned nr_pages,
4146 get_extent_t get_extent)
4147{
4148 struct bio *bio = NULL;
4149 unsigned page_idx;
4150 unsigned long bio_flags = 0;
4151 struct page *pagepool[16];
4152 struct page *page;
4153 struct extent_map *em_cached = NULL;
4154 int nr = 0;
4155 u64 prev_em_start = (u64)-1;
4156
4157 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
4158 page = list_entry(pages->prev, struct page, lru);
4159
4160 prefetchw(&page->flags);
4161 list_del(&page->lru);
4162 if (add_to_page_cache_lru(page, mapping,
4163 page->index, GFP_NOFS)) {
4164 put_page(page);
4165 continue;
4166 }
4167
4168 pagepool[nr++] = page;
4169 if (nr < ARRAY_SIZE(pagepool))
4170 continue;
4171 __extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4172 &bio, 0, &bio_flags, READ, &prev_em_start);
4173 nr = 0;
4174 }
4175 if (nr)
4176 __extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4177 &bio, 0, &bio_flags, READ, &prev_em_start);
4178
4179 if (em_cached)
4180 free_extent_map(em_cached);
4181
4182 BUG_ON(!list_empty(pages));
4183 if (bio)
4184 return submit_one_bio(READ, bio, 0, bio_flags);
4185 return 0;
4186}
4187
4188/*
4189 * basic invalidatepage code, this waits on any locked or writeback
4190 * ranges corresponding to the page, and then deletes any extent state
4191 * records from the tree
4192 */
4193int extent_invalidatepage(struct extent_io_tree *tree,
4194 struct page *page, unsigned long offset)
4195{
4196 struct extent_state *cached_state = NULL;
4197 u64 start = page_offset(page);
4198 u64 end = start + PAGE_SIZE - 1;
4199 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
4200
4201 start += ALIGN(offset, blocksize);
4202 if (start > end)
4203 return 0;
4204
4205 lock_extent_bits(tree, start, end, &cached_state);
4206 wait_on_page_writeback(page);
4207 clear_extent_bit(tree, start, end,
4208 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
4209 EXTENT_DO_ACCOUNTING,
4210 1, 1, &cached_state, GFP_NOFS);
4211 return 0;
4212}
4213
4214/*
4215 * a helper for releasepage, this tests for areas of the page that
4216 * are locked or under IO and drops the related state bits if it is safe
4217 * to drop the page.
4218 */
4219static int try_release_extent_state(struct extent_map_tree *map,
4220 struct extent_io_tree *tree,
4221 struct page *page, gfp_t mask)
4222{
4223 u64 start = page_offset(page);
4224 u64 end = start + PAGE_SIZE - 1;
4225 int ret = 1;
4226
4227 if (test_range_bit(tree, start, end,
4228 EXTENT_IOBITS, 0, NULL))
4229 ret = 0;
4230 else {
4231 if ((mask & GFP_NOFS) == GFP_NOFS)
4232 mask = GFP_NOFS;
4233 /*
4234 * at this point we can safely clear everything except the
4235 * locked bit and the nodatasum bit
4236 */
4237 ret = clear_extent_bit(tree, start, end,
4238 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
4239 0, 0, NULL, mask);
4240
4241 /* if clear_extent_bit failed for enomem reasons,
4242 * we can't allow the release to continue.
4243 */
4244 if (ret < 0)
4245 ret = 0;
4246 else
4247 ret = 1;
4248 }
4249 return ret;
4250}
4251
4252/*
4253 * a helper for releasepage. As long as there are no locked extents
4254 * in the range corresponding to the page, both state records and extent
4255 * map records are removed
4256 */
4257int try_release_extent_mapping(struct extent_map_tree *map,
4258 struct extent_io_tree *tree, struct page *page,
4259 gfp_t mask)
4260{
4261 struct extent_map *em;
4262 u64 start = page_offset(page);
4263 u64 end = start + PAGE_SIZE - 1;
4264
4265 if (gfpflags_allow_blocking(mask) &&
4266 page->mapping->host->i_size > SZ_16M) {
4267 u64 len;
4268 while (start <= end) {
4269 len = end - start + 1;
4270 write_lock(&map->lock);
4271 em = lookup_extent_mapping(map, start, len);
4272 if (!em) {
4273 write_unlock(&map->lock);
4274 break;
4275 }
4276 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
4277 em->start != start) {
4278 write_unlock(&map->lock);
4279 free_extent_map(em);
4280 break;
4281 }
4282 if (!test_range_bit(tree, em->start,
4283 extent_map_end(em) - 1,
4284 EXTENT_LOCKED | EXTENT_WRITEBACK,
4285 0, NULL)) {
4286 remove_extent_mapping(map, em);
4287 /* once for the rb tree */
4288 free_extent_map(em);
4289 }
4290 start = extent_map_end(em);
4291 write_unlock(&map->lock);
4292
4293 /* once for us */
4294 free_extent_map(em);
4295 }
4296 }
4297 return try_release_extent_state(map, tree, page, mask);
4298}
4299
4300/*
4301 * helper function for fiemap, which doesn't want to see any holes.
4302 * This maps until we find something past 'last'
4303 */
4304static struct extent_map *get_extent_skip_holes(struct inode *inode,
4305 u64 offset,
4306 u64 last,
4307 get_extent_t *get_extent)
4308{
4309 u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
4310 struct extent_map *em;
4311 u64 len;
4312
4313 if (offset >= last)
4314 return NULL;
4315
4316 while (1) {
4317 len = last - offset;
4318 if (len == 0)
4319 break;
4320 len = ALIGN(len, sectorsize);
4321 em = get_extent(inode, NULL, 0, offset, len, 0);
4322 if (IS_ERR_OR_NULL(em))
4323 return em;
4324
4325 /* if this isn't a hole return it */
4326 if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
4327 em->block_start != EXTENT_MAP_HOLE) {
4328 return em;
4329 }
4330
4331 /* this is a hole, advance to the next extent */
4332 offset = extent_map_end(em);
4333 free_extent_map(em);
4334 if (offset >= last)
4335 break;
4336 }
4337 return NULL;
4338}
4339
4340int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4341 __u64 start, __u64 len, get_extent_t *get_extent)
4342{
4343 int ret = 0;
4344 u64 off = start;
4345 u64 max = start + len;
4346 u32 flags = 0;
4347 u32 found_type;
4348 u64 last;
4349 u64 last_for_get_extent = 0;
4350 u64 disko = 0;
4351 u64 isize = i_size_read(inode);
4352 struct btrfs_key found_key;
4353 struct extent_map *em = NULL;
4354 struct extent_state *cached_state = NULL;
4355 struct btrfs_path *path;
4356 struct btrfs_root *root = BTRFS_I(inode)->root;
4357 int end = 0;
4358 u64 em_start = 0;
4359 u64 em_len = 0;
4360 u64 em_end = 0;
4361
4362 if (len == 0)
4363 return -EINVAL;
4364
4365 path = btrfs_alloc_path();
4366 if (!path)
4367 return -ENOMEM;
4368 path->leave_spinning = 1;
4369
4370 start = round_down(start, BTRFS_I(inode)->root->sectorsize);
4371 len = round_up(max, BTRFS_I(inode)->root->sectorsize) - start;
4372
4373 /*
4374 * lookup the last file extent. We're not using i_size here
4375 * because there might be preallocation past i_size
4376 */
4377 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode), -1,
4378 0);
4379 if (ret < 0) {
4380 btrfs_free_path(path);
4381 return ret;
4382 }
4383 WARN_ON(!ret);
4384 path->slots[0]--;
4385 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
4386 found_type = found_key.type;
4387
4388 /* No extents, but there might be delalloc bits */
4389 if (found_key.objectid != btrfs_ino(inode) ||
4390 found_type != BTRFS_EXTENT_DATA_KEY) {
4391 /* have to trust i_size as the end */
4392 last = (u64)-1;
4393 last_for_get_extent = isize;
4394 } else {
4395 /*
4396 * remember the start of the last extent. There are a
4397 * bunch of different factors that go into the length of the
4398 * extent, so its much less complex to remember where it started
4399 */
4400 last = found_key.offset;
4401 last_for_get_extent = last + 1;
4402 }
4403 btrfs_release_path(path);
4404
4405 /*
4406 * we might have some extents allocated but more delalloc past those
4407 * extents. so, we trust isize unless the start of the last extent is
4408 * beyond isize
4409 */
4410 if (last < isize) {
4411 last = (u64)-1;
4412 last_for_get_extent = isize;
4413 }
4414
4415 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4416 &cached_state);
4417
4418 em = get_extent_skip_holes(inode, start, last_for_get_extent,
4419 get_extent);
4420 if (!em)
4421 goto out;
4422 if (IS_ERR(em)) {
4423 ret = PTR_ERR(em);
4424 goto out;
4425 }
4426
4427 while (!end) {
4428 u64 offset_in_extent = 0;
4429
4430 /* break if the extent we found is outside the range */
4431 if (em->start >= max || extent_map_end(em) < off)
4432 break;
4433
4434 /*
4435 * get_extent may return an extent that starts before our
4436 * requested range. We have to make sure the ranges
4437 * we return to fiemap always move forward and don't
4438 * overlap, so adjust the offsets here
4439 */
4440 em_start = max(em->start, off);
4441
4442 /*
4443 * record the offset from the start of the extent
4444 * for adjusting the disk offset below. Only do this if the
4445 * extent isn't compressed since our in ram offset may be past
4446 * what we have actually allocated on disk.
4447 */
4448 if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4449 offset_in_extent = em_start - em->start;
4450 em_end = extent_map_end(em);
4451 em_len = em_end - em_start;
4452 disko = 0;
4453 flags = 0;
4454
4455 /*
4456 * bump off for our next call to get_extent
4457 */
4458 off = extent_map_end(em);
4459 if (off >= max)
4460 end = 1;
4461
4462 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
4463 end = 1;
4464 flags |= FIEMAP_EXTENT_LAST;
4465 } else if (em->block_start == EXTENT_MAP_INLINE) {
4466 flags |= (FIEMAP_EXTENT_DATA_INLINE |
4467 FIEMAP_EXTENT_NOT_ALIGNED);
4468 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
4469 flags |= (FIEMAP_EXTENT_DELALLOC |
4470 FIEMAP_EXTENT_UNKNOWN);
4471 } else if (fieinfo->fi_extents_max) {
4472 u64 bytenr = em->block_start -
4473 (em->start - em->orig_start);
4474
4475 disko = em->block_start + offset_in_extent;
4476
4477 /*
4478 * As btrfs supports shared space, this information
4479 * can be exported to userspace tools via
4480 * flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0
4481 * then we're just getting a count and we can skip the
4482 * lookup stuff.
4483 */
4484 ret = btrfs_check_shared(NULL, root->fs_info,
4485 root->objectid,
4486 btrfs_ino(inode), bytenr);
4487 if (ret < 0)
4488 goto out_free;
4489 if (ret)
4490 flags |= FIEMAP_EXTENT_SHARED;
4491 ret = 0;
4492 }
4493 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4494 flags |= FIEMAP_EXTENT_ENCODED;
4495 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
4496 flags |= FIEMAP_EXTENT_UNWRITTEN;
4497
4498 free_extent_map(em);
4499 em = NULL;
4500 if ((em_start >= last) || em_len == (u64)-1 ||
4501 (last == (u64)-1 && isize <= em_end)) {
4502 flags |= FIEMAP_EXTENT_LAST;
4503 end = 1;
4504 }
4505
4506 /* now scan forward to see if this is really the last extent. */
4507 em = get_extent_skip_holes(inode, off, last_for_get_extent,
4508 get_extent);
4509 if (IS_ERR(em)) {
4510 ret = PTR_ERR(em);
4511 goto out;
4512 }
4513 if (!em) {
4514 flags |= FIEMAP_EXTENT_LAST;
4515 end = 1;
4516 }
4517 ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
4518 em_len, flags);
4519 if (ret) {
4520 if (ret == 1)
4521 ret = 0;
4522 goto out_free;
4523 }
4524 }
4525out_free:
4526 free_extent_map(em);
4527out:
4528 btrfs_free_path(path);
4529 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4530 &cached_state, GFP_NOFS);
4531 return ret;
4532}
4533
4534static void __free_extent_buffer(struct extent_buffer *eb)
4535{
4536 btrfs_leak_debug_del(&eb->leak_list);
4537 kmem_cache_free(extent_buffer_cache, eb);
4538}
4539
4540int extent_buffer_under_io(struct extent_buffer *eb)
4541{
4542 return (atomic_read(&eb->io_pages) ||
4543 test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
4544 test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4545}
4546
4547/*
4548 * Helper for releasing extent buffer page.
4549 */
4550static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
4551{
4552 unsigned long index;
4553 struct page *page;
4554 int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4555
4556 BUG_ON(extent_buffer_under_io(eb));
4557
4558 index = num_extent_pages(eb->start, eb->len);
4559 if (index == 0)
4560 return;
4561
4562 do {
4563 index--;
4564 page = eb->pages[index];
4565 if (!page)
4566 continue;
4567 if (mapped)
4568 spin_lock(&page->mapping->private_lock);
4569 /*
4570 * We do this since we'll remove the pages after we've
4571 * removed the eb from the radix tree, so we could race
4572 * and have this page now attached to the new eb. So
4573 * only clear page_private if it's still connected to
4574 * this eb.
4575 */
4576 if (PagePrivate(page) &&
4577 page->private == (unsigned long)eb) {
4578 BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4579 BUG_ON(PageDirty(page));
4580 BUG_ON(PageWriteback(page));
4581 /*
4582 * We need to make sure we haven't be attached
4583 * to a new eb.
4584 */
4585 ClearPagePrivate(page);
4586 set_page_private(page, 0);
4587 /* One for the page private */
4588 put_page(page);
4589 }
4590
4591 if (mapped)
4592 spin_unlock(&page->mapping->private_lock);
4593
4594 /* One for when we alloced the page */
4595 put_page(page);
4596 } while (index != 0);
4597}
4598
4599/*
4600 * Helper for releasing the extent buffer.
4601 */
4602static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
4603{
4604 btrfs_release_extent_buffer_page(eb);
4605 __free_extent_buffer(eb);
4606}
4607
4608static struct extent_buffer *
4609__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
4610 unsigned long len)
4611{
4612 struct extent_buffer *eb = NULL;
4613
4614 eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
4615 eb->start = start;
4616 eb->len = len;
4617 eb->fs_info = fs_info;
4618 eb->bflags = 0;
4619 rwlock_init(&eb->lock);
4620 atomic_set(&eb->write_locks, 0);
4621 atomic_set(&eb->read_locks, 0);
4622 atomic_set(&eb->blocking_readers, 0);
4623 atomic_set(&eb->blocking_writers, 0);
4624 atomic_set(&eb->spinning_readers, 0);
4625 atomic_set(&eb->spinning_writers, 0);
4626 eb->lock_nested = 0;
4627 init_waitqueue_head(&eb->write_lock_wq);
4628 init_waitqueue_head(&eb->read_lock_wq);
4629
4630 btrfs_leak_debug_add(&eb->leak_list, &buffers);
4631
4632 spin_lock_init(&eb->refs_lock);
4633 atomic_set(&eb->refs, 1);
4634 atomic_set(&eb->io_pages, 0);
4635
4636 /*
4637 * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
4638 */
4639 BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
4640 > MAX_INLINE_EXTENT_BUFFER_SIZE);
4641 BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
4642
4643 return eb;
4644}
4645
4646struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
4647{
4648 unsigned long i;
4649 struct page *p;
4650 struct extent_buffer *new;
4651 unsigned long num_pages = num_extent_pages(src->start, src->len);
4652
4653 new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
4654 if (new == NULL)
4655 return NULL;
4656
4657 for (i = 0; i < num_pages; i++) {
4658 p = alloc_page(GFP_NOFS);
4659 if (!p) {
4660 btrfs_release_extent_buffer(new);
4661 return NULL;
4662 }
4663 attach_extent_buffer_page(new, p);
4664 WARN_ON(PageDirty(p));
4665 SetPageUptodate(p);
4666 new->pages[i] = p;
4667 }
4668
4669 copy_extent_buffer(new, src, 0, 0, src->len);
4670 set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
4671 set_bit(EXTENT_BUFFER_DUMMY, &new->bflags);
4672
4673 return new;
4674}
4675
4676struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4677 u64 start, unsigned long len)
4678{
4679 struct extent_buffer *eb;
4680 unsigned long num_pages;
4681 unsigned long i;
4682
4683 num_pages = num_extent_pages(start, len);
4684
4685 eb = __alloc_extent_buffer(fs_info, start, len);
4686 if (!eb)
4687 return NULL;
4688
4689 for (i = 0; i < num_pages; i++) {
4690 eb->pages[i] = alloc_page(GFP_NOFS);
4691 if (!eb->pages[i])
4692 goto err;
4693 }
4694 set_extent_buffer_uptodate(eb);
4695 btrfs_set_header_nritems(eb, 0);
4696 set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4697
4698 return eb;
4699err:
4700 for (; i > 0; i--)
4701 __free_page(eb->pages[i - 1]);
4702 __free_extent_buffer(eb);
4703 return NULL;
4704}
4705
4706struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4707 u64 start)
4708{
4709 unsigned long len;
4710
4711 if (!fs_info) {
4712 /*
4713 * Called only from tests that don't always have a fs_info
4714 * available, but we know that nodesize is 4096
4715 */
4716 len = 4096;
4717 } else {
4718 len = fs_info->tree_root->nodesize;
4719 }
4720
4721 return __alloc_dummy_extent_buffer(fs_info, start, len);
4722}
4723
4724static void check_buffer_tree_ref(struct extent_buffer *eb)
4725{
4726 int refs;
4727 /* the ref bit is tricky. We have to make sure it is set
4728 * if we have the buffer dirty. Otherwise the
4729 * code to free a buffer can end up dropping a dirty
4730 * page
4731 *
4732 * Once the ref bit is set, it won't go away while the
4733 * buffer is dirty or in writeback, and it also won't
4734 * go away while we have the reference count on the
4735 * eb bumped.
4736 *
4737 * We can't just set the ref bit without bumping the
4738 * ref on the eb because free_extent_buffer might
4739 * see the ref bit and try to clear it. If this happens
4740 * free_extent_buffer might end up dropping our original
4741 * ref by mistake and freeing the page before we are able
4742 * to add one more ref.
4743 *
4744 * So bump the ref count first, then set the bit. If someone
4745 * beat us to it, drop the ref we added.
4746 */
4747 refs = atomic_read(&eb->refs);
4748 if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4749 return;
4750
4751 spin_lock(&eb->refs_lock);
4752 if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4753 atomic_inc(&eb->refs);
4754 spin_unlock(&eb->refs_lock);
4755}
4756
4757static void mark_extent_buffer_accessed(struct extent_buffer *eb,
4758 struct page *accessed)
4759{
4760 unsigned long num_pages, i;
4761
4762 check_buffer_tree_ref(eb);
4763
4764 num_pages = num_extent_pages(eb->start, eb->len);
4765 for (i = 0; i < num_pages; i++) {
4766 struct page *p = eb->pages[i];
4767
4768 if (p != accessed)
4769 mark_page_accessed(p);
4770 }
4771}
4772
4773struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
4774 u64 start)
4775{
4776 struct extent_buffer *eb;
4777
4778 rcu_read_lock();
4779 eb = radix_tree_lookup(&fs_info->buffer_radix,
4780 start >> PAGE_SHIFT);
4781 if (eb && atomic_inc_not_zero(&eb->refs)) {
4782 rcu_read_unlock();
4783 /*
4784 * Lock our eb's refs_lock to avoid races with
4785 * free_extent_buffer. When we get our eb it might be flagged
4786 * with EXTENT_BUFFER_STALE and another task running
4787 * free_extent_buffer might have seen that flag set,
4788 * eb->refs == 2, that the buffer isn't under IO (dirty and
4789 * writeback flags not set) and it's still in the tree (flag
4790 * EXTENT_BUFFER_TREE_REF set), therefore being in the process
4791 * of decrementing the extent buffer's reference count twice.
4792 * So here we could race and increment the eb's reference count,
4793 * clear its stale flag, mark it as dirty and drop our reference
4794 * before the other task finishes executing free_extent_buffer,
4795 * which would later result in an attempt to free an extent
4796 * buffer that is dirty.
4797 */
4798 if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
4799 spin_lock(&eb->refs_lock);
4800 spin_unlock(&eb->refs_lock);
4801 }
4802 mark_extent_buffer_accessed(eb, NULL);
4803 return eb;
4804 }
4805 rcu_read_unlock();
4806
4807 return NULL;
4808}
4809
4810#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4811struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
4812 u64 start)
4813{
4814 struct extent_buffer *eb, *exists = NULL;
4815 int ret;
4816
4817 eb = find_extent_buffer(fs_info, start);
4818 if (eb)
4819 return eb;
4820 eb = alloc_dummy_extent_buffer(fs_info, start);
4821 if (!eb)
4822 return NULL;
4823 eb->fs_info = fs_info;
4824again:
4825 ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
4826 if (ret)
4827 goto free_eb;
4828 spin_lock(&fs_info->buffer_lock);
4829 ret = radix_tree_insert(&fs_info->buffer_radix,
4830 start >> PAGE_SHIFT, eb);
4831 spin_unlock(&fs_info->buffer_lock);
4832 radix_tree_preload_end();
4833 if (ret == -EEXIST) {
4834 exists = find_extent_buffer(fs_info, start);
4835 if (exists)
4836 goto free_eb;
4837 else
4838 goto again;
4839 }
4840 check_buffer_tree_ref(eb);
4841 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4842
4843 /*
4844 * We will free dummy extent buffer's if they come into
4845 * free_extent_buffer with a ref count of 2, but if we are using this we
4846 * want the buffers to stay in memory until we're done with them, so
4847 * bump the ref count again.
4848 */
4849 atomic_inc(&eb->refs);
4850 return eb;
4851free_eb:
4852 btrfs_release_extent_buffer(eb);
4853 return exists;
4854}
4855#endif
4856
4857struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4858 u64 start)
4859{
4860 unsigned long len = fs_info->tree_root->nodesize;
4861 unsigned long num_pages = num_extent_pages(start, len);
4862 unsigned long i;
4863 unsigned long index = start >> PAGE_SHIFT;
4864 struct extent_buffer *eb;
4865 struct extent_buffer *exists = NULL;
4866 struct page *p;
4867 struct address_space *mapping = fs_info->btree_inode->i_mapping;
4868 int uptodate = 1;
4869 int ret;
4870
4871 eb = find_extent_buffer(fs_info, start);
4872 if (eb)
4873 return eb;
4874
4875 eb = __alloc_extent_buffer(fs_info, start, len);
4876 if (!eb)
4877 return NULL;
4878
4879 for (i = 0; i < num_pages; i++, index++) {
4880 p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
4881 if (!p)
4882 goto free_eb;
4883
4884 spin_lock(&mapping->private_lock);
4885 if (PagePrivate(p)) {
4886 /*
4887 * We could have already allocated an eb for this page
4888 * and attached one so lets see if we can get a ref on
4889 * the existing eb, and if we can we know it's good and
4890 * we can just return that one, else we know we can just
4891 * overwrite page->private.
4892 */
4893 exists = (struct extent_buffer *)p->private;
4894 if (atomic_inc_not_zero(&exists->refs)) {
4895 spin_unlock(&mapping->private_lock);
4896 unlock_page(p);
4897 put_page(p);
4898 mark_extent_buffer_accessed(exists, p);
4899 goto free_eb;
4900 }
4901 exists = NULL;
4902
4903 /*
4904 * Do this so attach doesn't complain and we need to
4905 * drop the ref the old guy had.
4906 */
4907 ClearPagePrivate(p);
4908 WARN_ON(PageDirty(p));
4909 put_page(p);
4910 }
4911 attach_extent_buffer_page(eb, p);
4912 spin_unlock(&mapping->private_lock);
4913 WARN_ON(PageDirty(p));
4914 eb->pages[i] = p;
4915 if (!PageUptodate(p))
4916 uptodate = 0;
4917
4918 /*
4919 * see below about how we avoid a nasty race with release page
4920 * and why we unlock later
4921 */
4922 }
4923 if (uptodate)
4924 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4925again:
4926 ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
4927 if (ret)
4928 goto free_eb;
4929
4930 spin_lock(&fs_info->buffer_lock);
4931 ret = radix_tree_insert(&fs_info->buffer_radix,
4932 start >> PAGE_SHIFT, eb);
4933 spin_unlock(&fs_info->buffer_lock);
4934 radix_tree_preload_end();
4935 if (ret == -EEXIST) {
4936 exists = find_extent_buffer(fs_info, start);
4937 if (exists)
4938 goto free_eb;
4939 else
4940 goto again;
4941 }
4942 /* add one reference for the tree */
4943 check_buffer_tree_ref(eb);
4944 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4945
4946 /*
4947 * there is a race where release page may have
4948 * tried to find this extent buffer in the radix
4949 * but failed. It will tell the VM it is safe to
4950 * reclaim the, and it will clear the page private bit.
4951 * We must make sure to set the page private bit properly
4952 * after the extent buffer is in the radix tree so
4953 * it doesn't get lost
4954 */
4955 SetPageChecked(eb->pages[0]);
4956 for (i = 1; i < num_pages; i++) {
4957 p = eb->pages[i];
4958 ClearPageChecked(p);
4959 unlock_page(p);
4960 }
4961 unlock_page(eb->pages[0]);
4962 return eb;
4963
4964free_eb:
4965 WARN_ON(!atomic_dec_and_test(&eb->refs));
4966 for (i = 0; i < num_pages; i++) {
4967 if (eb->pages[i])
4968 unlock_page(eb->pages[i]);
4969 }
4970
4971 btrfs_release_extent_buffer(eb);
4972 return exists;
4973}
4974
4975static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
4976{
4977 struct extent_buffer *eb =
4978 container_of(head, struct extent_buffer, rcu_head);
4979
4980 __free_extent_buffer(eb);
4981}
4982
4983/* Expects to have eb->eb_lock already held */
4984static int release_extent_buffer(struct extent_buffer *eb)
4985{
4986 WARN_ON(atomic_read(&eb->refs) == 0);
4987 if (atomic_dec_and_test(&eb->refs)) {
4988 if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
4989 struct btrfs_fs_info *fs_info = eb->fs_info;
4990
4991 spin_unlock(&eb->refs_lock);
4992
4993 spin_lock(&fs_info->buffer_lock);
4994 radix_tree_delete(&fs_info->buffer_radix,
4995 eb->start >> PAGE_SHIFT);
4996 spin_unlock(&fs_info->buffer_lock);
4997 } else {
4998 spin_unlock(&eb->refs_lock);
4999 }
5000
5001 /* Should be safe to release our pages at this point */
5002 btrfs_release_extent_buffer_page(eb);
5003#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5004 if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))) {
5005 __free_extent_buffer(eb);
5006 return 1;
5007 }
5008#endif
5009 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
5010 return 1;
5011 }
5012 spin_unlock(&eb->refs_lock);
5013
5014 return 0;
5015}
5016
5017void free_extent_buffer(struct extent_buffer *eb)
5018{
5019 int refs;
5020 int old;
5021 if (!eb)
5022 return;
5023
5024 while (1) {
5025 refs = atomic_read(&eb->refs);
5026 if (refs <= 3)
5027 break;
5028 old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
5029 if (old == refs)
5030 return;
5031 }
5032
5033 spin_lock(&eb->refs_lock);
5034 if (atomic_read(&eb->refs) == 2 &&
5035 test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
5036 atomic_dec(&eb->refs);
5037
5038 if (atomic_read(&eb->refs) == 2 &&
5039 test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
5040 !extent_buffer_under_io(eb) &&
5041 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5042 atomic_dec(&eb->refs);
5043
5044 /*
5045 * I know this is terrible, but it's temporary until we stop tracking
5046 * the uptodate bits and such for the extent buffers.
5047 */
5048 release_extent_buffer(eb);
5049}
5050
5051void free_extent_buffer_stale(struct extent_buffer *eb)
5052{
5053 if (!eb)
5054 return;
5055
5056 spin_lock(&eb->refs_lock);
5057 set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
5058
5059 if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
5060 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5061 atomic_dec(&eb->refs);
5062 release_extent_buffer(eb);
5063}
5064
5065void clear_extent_buffer_dirty(struct extent_buffer *eb)
5066{
5067 unsigned long i;
5068 unsigned long num_pages;
5069 struct page *page;
5070
5071 num_pages = num_extent_pages(eb->start, eb->len);
5072
5073 for (i = 0; i < num_pages; i++) {
5074 page = eb->pages[i];
5075 if (!PageDirty(page))
5076 continue;
5077
5078 lock_page(page);
5079 WARN_ON(!PagePrivate(page));
5080
5081 clear_page_dirty_for_io(page);
5082 spin_lock_irq(&page->mapping->tree_lock);
5083 if (!PageDirty(page)) {
5084 radix_tree_tag_clear(&page->mapping->page_tree,
5085 page_index(page),
5086 PAGECACHE_TAG_DIRTY);
5087 }
5088 spin_unlock_irq(&page->mapping->tree_lock);
5089 ClearPageError(page);
5090 unlock_page(page);
5091 }
5092 WARN_ON(atomic_read(&eb->refs) == 0);
5093}
5094
5095int set_extent_buffer_dirty(struct extent_buffer *eb)
5096{
5097 unsigned long i;
5098 unsigned long num_pages;
5099 int was_dirty = 0;
5100
5101 check_buffer_tree_ref(eb);
5102
5103 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
5104
5105 num_pages = num_extent_pages(eb->start, eb->len);
5106 WARN_ON(atomic_read(&eb->refs) == 0);
5107 WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
5108
5109 for (i = 0; i < num_pages; i++)
5110 set_page_dirty(eb->pages[i]);
5111 return was_dirty;
5112}
5113
5114void clear_extent_buffer_uptodate(struct extent_buffer *eb)
5115{
5116 unsigned long i;
5117 struct page *page;
5118 unsigned long num_pages;
5119
5120 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5121 num_pages = num_extent_pages(eb->start, eb->len);
5122 for (i = 0; i < num_pages; i++) {
5123 page = eb->pages[i];
5124 if (page)
5125 ClearPageUptodate(page);
5126 }
5127}
5128
5129void set_extent_buffer_uptodate(struct extent_buffer *eb)
5130{
5131 unsigned long i;
5132 struct page *page;
5133 unsigned long num_pages;
5134
5135 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5136 num_pages = num_extent_pages(eb->start, eb->len);
5137 for (i = 0; i < num_pages; i++) {
5138 page = eb->pages[i];
5139 SetPageUptodate(page);
5140 }
5141}
5142
5143int extent_buffer_uptodate(struct extent_buffer *eb)
5144{
5145 return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5146}
5147
5148int read_extent_buffer_pages(struct extent_io_tree *tree,
5149 struct extent_buffer *eb, u64 start, int wait,
5150 get_extent_t *get_extent, int mirror_num)
5151{
5152 unsigned long i;
5153 unsigned long start_i;
5154 struct page *page;
5155 int err;
5156 int ret = 0;
5157 int locked_pages = 0;
5158 int all_uptodate = 1;
5159 unsigned long num_pages;
5160 unsigned long num_reads = 0;
5161 struct bio *bio = NULL;
5162 unsigned long bio_flags = 0;
5163
5164 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
5165 return 0;
5166
5167 if (start) {
5168 WARN_ON(start < eb->start);
5169 start_i = (start >> PAGE_SHIFT) -
5170 (eb->start >> PAGE_SHIFT);
5171 } else {
5172 start_i = 0;
5173 }
5174
5175 num_pages = num_extent_pages(eb->start, eb->len);
5176 for (i = start_i; i < num_pages; i++) {
5177 page = eb->pages[i];
5178 if (wait == WAIT_NONE) {
5179 if (!trylock_page(page))
5180 goto unlock_exit;
5181 } else {
5182 lock_page(page);
5183 }
5184 locked_pages++;
5185 if (!PageUptodate(page)) {
5186 num_reads++;
5187 all_uptodate = 0;
5188 }
5189 }
5190 if (all_uptodate) {
5191 if (start_i == 0)
5192 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5193 goto unlock_exit;
5194 }
5195
5196 clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
5197 eb->read_mirror = 0;
5198 atomic_set(&eb->io_pages, num_reads);
5199 for (i = start_i; i < num_pages; i++) {
5200 page = eb->pages[i];
5201 if (!PageUptodate(page)) {
5202 ClearPageError(page);
5203 err = __extent_read_full_page(tree, page,
5204 get_extent, &bio,
5205 mirror_num, &bio_flags,
5206 READ | REQ_META);
5207 if (err)
5208 ret = err;
5209 } else {
5210 unlock_page(page);
5211 }
5212 }
5213
5214 if (bio) {
5215 err = submit_one_bio(READ | REQ_META, bio, mirror_num,
5216 bio_flags);
5217 if (err)
5218 return err;
5219 }
5220
5221 if (ret || wait != WAIT_COMPLETE)
5222 return ret;
5223
5224 for (i = start_i; i < num_pages; i++) {
5225 page = eb->pages[i];
5226 wait_on_page_locked(page);
5227 if (!PageUptodate(page))
5228 ret = -EIO;
5229 }
5230
5231 return ret;
5232
5233unlock_exit:
5234 i = start_i;
5235 while (locked_pages > 0) {
5236 page = eb->pages[i];
5237 i++;
5238 unlock_page(page);
5239 locked_pages--;
5240 }
5241 return ret;
5242}
5243
5244void read_extent_buffer(struct extent_buffer *eb, void *dstv,
5245 unsigned long start,
5246 unsigned long len)
5247{
5248 size_t cur;
5249 size_t offset;
5250 struct page *page;
5251 char *kaddr;
5252 char *dst = (char *)dstv;
5253 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5254 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5255
5256 WARN_ON(start > eb->len);
5257 WARN_ON(start + len > eb->start + eb->len);
5258
5259 offset = (start_offset + start) & (PAGE_SIZE - 1);
5260
5261 while (len > 0) {
5262 page = eb->pages[i];
5263
5264 cur = min(len, (PAGE_SIZE - offset));
5265 kaddr = page_address(page);
5266 memcpy(dst, kaddr + offset, cur);
5267
5268 dst += cur;
5269 len -= cur;
5270 offset = 0;
5271 i++;
5272 }
5273}
5274
5275int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
5276 unsigned long start,
5277 unsigned long len)
5278{
5279 size_t cur;
5280 size_t offset;
5281 struct page *page;
5282 char *kaddr;
5283 char __user *dst = (char __user *)dstv;
5284 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5285 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5286 int ret = 0;
5287
5288 WARN_ON(start > eb->len);
5289 WARN_ON(start + len > eb->start + eb->len);
5290
5291 offset = (start_offset + start) & (PAGE_SIZE - 1);
5292
5293 while (len > 0) {
5294 page = eb->pages[i];
5295
5296 cur = min(len, (PAGE_SIZE - offset));
5297 kaddr = page_address(page);
5298 if (copy_to_user(dst, kaddr + offset, cur)) {
5299 ret = -EFAULT;
5300 break;
5301 }
5302
5303 dst += cur;
5304 len -= cur;
5305 offset = 0;
5306 i++;
5307 }
5308
5309 return ret;
5310}
5311
5312int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
5313 unsigned long min_len, char **map,
5314 unsigned long *map_start,
5315 unsigned long *map_len)
5316{
5317 size_t offset = start & (PAGE_SIZE - 1);
5318 char *kaddr;
5319 struct page *p;
5320 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5321 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5322 unsigned long end_i = (start_offset + start + min_len - 1) >>
5323 PAGE_SHIFT;
5324
5325 if (i != end_i)
5326 return -EINVAL;
5327
5328 if (i == 0) {
5329 offset = start_offset;
5330 *map_start = 0;
5331 } else {
5332 offset = 0;
5333 *map_start = ((u64)i << PAGE_SHIFT) - start_offset;
5334 }
5335
5336 if (start + min_len > eb->len) {
5337 WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
5338 "wanted %lu %lu\n",
5339 eb->start, eb->len, start, min_len);
5340 return -EINVAL;
5341 }
5342
5343 p = eb->pages[i];
5344 kaddr = page_address(p);
5345 *map = kaddr + offset;
5346 *map_len = PAGE_SIZE - offset;
5347 return 0;
5348}
5349
5350int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
5351 unsigned long start,
5352 unsigned long len)
5353{
5354 size_t cur;
5355 size_t offset;
5356 struct page *page;
5357 char *kaddr;
5358 char *ptr = (char *)ptrv;
5359 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5360 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5361 int ret = 0;
5362
5363 WARN_ON(start > eb->len);
5364 WARN_ON(start + len > eb->start + eb->len);
5365
5366 offset = (start_offset + start) & (PAGE_SIZE - 1);
5367
5368 while (len > 0) {
5369 page = eb->pages[i];
5370
5371 cur = min(len, (PAGE_SIZE - offset));
5372
5373 kaddr = page_address(page);
5374 ret = memcmp(ptr, kaddr + offset, cur);
5375 if (ret)
5376 break;
5377
5378 ptr += cur;
5379 len -= cur;
5380 offset = 0;
5381 i++;
5382 }
5383 return ret;
5384}
5385
5386void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
5387 unsigned long start, unsigned long len)
5388{
5389 size_t cur;
5390 size_t offset;
5391 struct page *page;
5392 char *kaddr;
5393 char *src = (char *)srcv;
5394 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5395 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5396
5397 WARN_ON(start > eb->len);
5398 WARN_ON(start + len > eb->start + eb->len);
5399
5400 offset = (start_offset + start) & (PAGE_SIZE - 1);
5401
5402 while (len > 0) {
5403 page = eb->pages[i];
5404 WARN_ON(!PageUptodate(page));
5405
5406 cur = min(len, PAGE_SIZE - offset);
5407 kaddr = page_address(page);
5408 memcpy(kaddr + offset, src, cur);
5409
5410 src += cur;
5411 len -= cur;
5412 offset = 0;
5413 i++;
5414 }
5415}
5416
5417void memset_extent_buffer(struct extent_buffer *eb, char c,
5418 unsigned long start, unsigned long len)
5419{
5420 size_t cur;
5421 size_t offset;
5422 struct page *page;
5423 char *kaddr;
5424 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5425 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5426
5427 WARN_ON(start > eb->len);
5428 WARN_ON(start + len > eb->start + eb->len);
5429
5430 offset = (start_offset + start) & (PAGE_SIZE - 1);
5431
5432 while (len > 0) {
5433 page = eb->pages[i];
5434 WARN_ON(!PageUptodate(page));
5435
5436 cur = min(len, PAGE_SIZE - offset);
5437 kaddr = page_address(page);
5438 memset(kaddr + offset, c, cur);
5439
5440 len -= cur;
5441 offset = 0;
5442 i++;
5443 }
5444}
5445
5446void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
5447 unsigned long dst_offset, unsigned long src_offset,
5448 unsigned long len)
5449{
5450 u64 dst_len = dst->len;
5451 size_t cur;
5452 size_t offset;
5453 struct page *page;
5454 char *kaddr;
5455 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5456 unsigned long i = (start_offset + dst_offset) >> PAGE_SHIFT;
5457
5458 WARN_ON(src->len != dst_len);
5459
5460 offset = (start_offset + dst_offset) &
5461 (PAGE_SIZE - 1);
5462
5463 while (len > 0) {
5464 page = dst->pages[i];
5465 WARN_ON(!PageUptodate(page));
5466
5467 cur = min(len, (unsigned long)(PAGE_SIZE - offset));
5468
5469 kaddr = page_address(page);
5470 read_extent_buffer(src, kaddr + offset, src_offset, cur);
5471
5472 src_offset += cur;
5473 len -= cur;
5474 offset = 0;
5475 i++;
5476 }
5477}
5478
5479/*
5480 * The extent buffer bitmap operations are done with byte granularity because
5481 * bitmap items are not guaranteed to be aligned to a word and therefore a
5482 * single word in a bitmap may straddle two pages in the extent buffer.
5483 */
5484#define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
5485#define BYTE_MASK ((1 << BITS_PER_BYTE) - 1)
5486#define BITMAP_FIRST_BYTE_MASK(start) \
5487 ((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK)
5488#define BITMAP_LAST_BYTE_MASK(nbits) \
5489 (BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))
5490
5491/*
5492 * eb_bitmap_offset() - calculate the page and offset of the byte containing the
5493 * given bit number
5494 * @eb: the extent buffer
5495 * @start: offset of the bitmap item in the extent buffer
5496 * @nr: bit number
5497 * @page_index: return index of the page in the extent buffer that contains the
5498 * given bit number
5499 * @page_offset: return offset into the page given by page_index
5500 *
5501 * This helper hides the ugliness of finding the byte in an extent buffer which
5502 * contains a given bit.
5503 */
5504static inline void eb_bitmap_offset(struct extent_buffer *eb,
5505 unsigned long start, unsigned long nr,
5506 unsigned long *page_index,
5507 size_t *page_offset)
5508{
5509 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5510 size_t byte_offset = BIT_BYTE(nr);
5511 size_t offset;
5512
5513 /*
5514 * The byte we want is the offset of the extent buffer + the offset of
5515 * the bitmap item in the extent buffer + the offset of the byte in the
5516 * bitmap item.
5517 */
5518 offset = start_offset + start + byte_offset;
5519
5520 *page_index = offset >> PAGE_SHIFT;
5521 *page_offset = offset & (PAGE_SIZE - 1);
5522}
5523
5524/**
5525 * extent_buffer_test_bit - determine whether a bit in a bitmap item is set
5526 * @eb: the extent buffer
5527 * @start: offset of the bitmap item in the extent buffer
5528 * @nr: bit number to test
5529 */
5530int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
5531 unsigned long nr)
5532{
5533 char *kaddr;
5534 struct page *page;
5535 unsigned long i;
5536 size_t offset;
5537
5538 eb_bitmap_offset(eb, start, nr, &i, &offset);
5539 page = eb->pages[i];
5540 WARN_ON(!PageUptodate(page));
5541 kaddr = page_address(page);
5542 return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
5543}
5544
5545/**
5546 * extent_buffer_bitmap_set - set an area of a bitmap
5547 * @eb: the extent buffer
5548 * @start: offset of the bitmap item in the extent buffer
5549 * @pos: bit number of the first bit
5550 * @len: number of bits to set
5551 */
5552void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
5553 unsigned long pos, unsigned long len)
5554{
5555 char *kaddr;
5556 struct page *page;
5557 unsigned long i;
5558 size_t offset;
5559 const unsigned int size = pos + len;
5560 int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5561 unsigned int mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
5562
5563 eb_bitmap_offset(eb, start, pos, &i, &offset);
5564 page = eb->pages[i];
5565 WARN_ON(!PageUptodate(page));
5566 kaddr = page_address(page);
5567
5568 while (len >= bits_to_set) {
5569 kaddr[offset] |= mask_to_set;
5570 len -= bits_to_set;
5571 bits_to_set = BITS_PER_BYTE;
5572 mask_to_set = ~0U;
5573 if (++offset >= PAGE_SIZE && len > 0) {
5574 offset = 0;
5575 page = eb->pages[++i];
5576 WARN_ON(!PageUptodate(page));
5577 kaddr = page_address(page);
5578 }
5579 }
5580 if (len) {
5581 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5582 kaddr[offset] |= mask_to_set;
5583 }
5584}
5585
5586
5587/**
5588 * extent_buffer_bitmap_clear - clear an area of a bitmap
5589 * @eb: the extent buffer
5590 * @start: offset of the bitmap item in the extent buffer
5591 * @pos: bit number of the first bit
5592 * @len: number of bits to clear
5593 */
5594void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
5595 unsigned long pos, unsigned long len)
5596{
5597 char *kaddr;
5598 struct page *page;
5599 unsigned long i;
5600 size_t offset;
5601 const unsigned int size = pos + len;
5602 int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5603 unsigned int mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
5604
5605 eb_bitmap_offset(eb, start, pos, &i, &offset);
5606 page = eb->pages[i];
5607 WARN_ON(!PageUptodate(page));
5608 kaddr = page_address(page);
5609
5610 while (len >= bits_to_clear) {
5611 kaddr[offset] &= ~mask_to_clear;
5612 len -= bits_to_clear;
5613 bits_to_clear = BITS_PER_BYTE;
5614 mask_to_clear = ~0U;
5615 if (++offset >= PAGE_SIZE && len > 0) {
5616 offset = 0;
5617 page = eb->pages[++i];
5618 WARN_ON(!PageUptodate(page));
5619 kaddr = page_address(page);
5620 }
5621 }
5622 if (len) {
5623 mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5624 kaddr[offset] &= ~mask_to_clear;
5625 }
5626}
5627
5628static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
5629{
5630 unsigned long distance = (src > dst) ? src - dst : dst - src;
5631 return distance < len;
5632}
5633
5634static void copy_pages(struct page *dst_page, struct page *src_page,
5635 unsigned long dst_off, unsigned long src_off,
5636 unsigned long len)
5637{
5638 char *dst_kaddr = page_address(dst_page);
5639 char *src_kaddr;
5640 int must_memmove = 0;
5641
5642 if (dst_page != src_page) {
5643 src_kaddr = page_address(src_page);
5644 } else {
5645 src_kaddr = dst_kaddr;
5646 if (areas_overlap(src_off, dst_off, len))
5647 must_memmove = 1;
5648 }
5649
5650 if (must_memmove)
5651 memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
5652 else
5653 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5654}
5655
5656void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5657 unsigned long src_offset, unsigned long len)
5658{
5659 size_t cur;
5660 size_t dst_off_in_page;
5661 size_t src_off_in_page;
5662 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5663 unsigned long dst_i;
5664 unsigned long src_i;
5665
5666 if (src_offset + len > dst->len) {
5667 btrfs_err(dst->fs_info,
5668 "memmove bogus src_offset %lu move "
5669 "len %lu dst len %lu", src_offset, len, dst->len);
5670 BUG_ON(1);
5671 }
5672 if (dst_offset + len > dst->len) {
5673 btrfs_err(dst->fs_info,
5674 "memmove bogus dst_offset %lu move "
5675 "len %lu dst len %lu", dst_offset, len, dst->len);
5676 BUG_ON(1);
5677 }
5678
5679 while (len > 0) {
5680 dst_off_in_page = (start_offset + dst_offset) &
5681 (PAGE_SIZE - 1);
5682 src_off_in_page = (start_offset + src_offset) &
5683 (PAGE_SIZE - 1);
5684
5685 dst_i = (start_offset + dst_offset) >> PAGE_SHIFT;
5686 src_i = (start_offset + src_offset) >> PAGE_SHIFT;
5687
5688 cur = min(len, (unsigned long)(PAGE_SIZE -
5689 src_off_in_page));
5690 cur = min_t(unsigned long, cur,
5691 (unsigned long)(PAGE_SIZE - dst_off_in_page));
5692
5693 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5694 dst_off_in_page, src_off_in_page, cur);
5695
5696 src_offset += cur;
5697 dst_offset += cur;
5698 len -= cur;
5699 }
5700}
5701
5702void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5703 unsigned long src_offset, unsigned long len)
5704{
5705 size_t cur;
5706 size_t dst_off_in_page;
5707 size_t src_off_in_page;
5708 unsigned long dst_end = dst_offset + len - 1;
5709 unsigned long src_end = src_offset + len - 1;
5710 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5711 unsigned long dst_i;
5712 unsigned long src_i;
5713
5714 if (src_offset + len > dst->len) {
5715 btrfs_err(dst->fs_info, "memmove bogus src_offset %lu move "
5716 "len %lu len %lu", src_offset, len, dst->len);
5717 BUG_ON(1);
5718 }
5719 if (dst_offset + len > dst->len) {
5720 btrfs_err(dst->fs_info, "memmove bogus dst_offset %lu move "
5721 "len %lu len %lu", dst_offset, len, dst->len);
5722 BUG_ON(1);
5723 }
5724 if (dst_offset < src_offset) {
5725 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
5726 return;
5727 }
5728 while (len > 0) {
5729 dst_i = (start_offset + dst_end) >> PAGE_SHIFT;
5730 src_i = (start_offset + src_end) >> PAGE_SHIFT;
5731
5732 dst_off_in_page = (start_offset + dst_end) &
5733 (PAGE_SIZE - 1);
5734 src_off_in_page = (start_offset + src_end) &
5735 (PAGE_SIZE - 1);
5736
5737 cur = min_t(unsigned long, len, src_off_in_page + 1);
5738 cur = min(cur, dst_off_in_page + 1);
5739 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5740 dst_off_in_page - cur + 1,
5741 src_off_in_page - cur + 1, cur);
5742
5743 dst_end -= cur;
5744 src_end -= cur;
5745 len -= cur;
5746 }
5747}
5748
5749int try_release_extent_buffer(struct page *page)
5750{
5751 struct extent_buffer *eb;
5752
5753 /*
5754 * We need to make sure noboody is attaching this page to an eb right
5755 * now.
5756 */
5757 spin_lock(&page->mapping->private_lock);
5758 if (!PagePrivate(page)) {
5759 spin_unlock(&page->mapping->private_lock);
5760 return 1;
5761 }
5762
5763 eb = (struct extent_buffer *)page->private;
5764 BUG_ON(!eb);
5765
5766 /*
5767 * This is a little awful but should be ok, we need to make sure that
5768 * the eb doesn't disappear out from under us while we're looking at
5769 * this page.
5770 */
5771 spin_lock(&eb->refs_lock);
5772 if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5773 spin_unlock(&eb->refs_lock);
5774 spin_unlock(&page->mapping->private_lock);
5775 return 0;
5776 }
5777 spin_unlock(&page->mapping->private_lock);
5778
5779 /*
5780 * If tree ref isn't set then we know the ref on this eb is a real ref,
5781 * so just return, this page will likely be freed soon anyway.
5782 */
5783 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
5784 spin_unlock(&eb->refs_lock);
5785 return 0;
5786 }
5787
5788 return release_extent_buffer(eb);
5789}