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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// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/bitops.h>
4#include <linux/slab.h>
5#include <linux/bio.h>
6#include <linux/mm.h>
7#include <linux/pagemap.h>
8#include <linux/page-flags.h>
9#include <linux/spinlock.h>
10#include <linux/blkdev.h>
11#include <linux/swap.h>
12#include <linux/writeback.h>
13#include <linux/pagevec.h>
14#include <linux/prefetch.h>
15#include <linux/cleancache.h>
16#include "extent_io.h"
17#include "extent_map.h"
18#include "ctree.h"
19#include "btrfs_inode.h"
20#include "volumes.h"
21#include "check-integrity.h"
22#include "locking.h"
23#include "rcu-string.h"
24#include "backref.h"
25#include "disk-io.h"
26
27static struct kmem_cache *extent_state_cache;
28static struct kmem_cache *extent_buffer_cache;
29static struct bio_set *btrfs_bioset;
30
31static inline bool extent_state_in_tree(const struct extent_state *state)
32{
33 return !RB_EMPTY_NODE(&state->rb_node);
34}
35
36#ifdef CONFIG_BTRFS_DEBUG
37static LIST_HEAD(buffers);
38static LIST_HEAD(states);
39
40static DEFINE_SPINLOCK(leak_lock);
41
42static inline
43void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
44{
45 unsigned long flags;
46
47 spin_lock_irqsave(&leak_lock, flags);
48 list_add(new, head);
49 spin_unlock_irqrestore(&leak_lock, flags);
50}
51
52static inline
53void btrfs_leak_debug_del(struct list_head *entry)
54{
55 unsigned long flags;
56
57 spin_lock_irqsave(&leak_lock, flags);
58 list_del(entry);
59 spin_unlock_irqrestore(&leak_lock, flags);
60}
61
62static inline
63void btrfs_leak_debug_check(void)
64{
65 struct extent_state *state;
66 struct extent_buffer *eb;
67
68 while (!list_empty(&states)) {
69 state = list_entry(states.next, struct extent_state, leak_list);
70 pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
71 state->start, state->end, state->state,
72 extent_state_in_tree(state),
73 refcount_read(&state->refs));
74 list_del(&state->leak_list);
75 kmem_cache_free(extent_state_cache, state);
76 }
77
78 while (!list_empty(&buffers)) {
79 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
80 pr_err("BTRFS: buffer leak start %llu len %lu refs %d bflags %lu\n",
81 eb->start, eb->len, atomic_read(&eb->refs), eb->bflags);
82 list_del(&eb->leak_list);
83 kmem_cache_free(extent_buffer_cache, eb);
84 }
85}
86
87#define btrfs_debug_check_extent_io_range(tree, start, end) \
88 __btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
89static inline void __btrfs_debug_check_extent_io_range(const char *caller,
90 struct extent_io_tree *tree, u64 start, u64 end)
91{
92 if (tree->ops && tree->ops->check_extent_io_range)
93 tree->ops->check_extent_io_range(tree->private_data, caller,
94 start, end);
95}
96#else
97#define btrfs_leak_debug_add(new, head) do {} while (0)
98#define btrfs_leak_debug_del(entry) do {} while (0)
99#define btrfs_leak_debug_check() do {} while (0)
100#define btrfs_debug_check_extent_io_range(c, s, e) do {} while (0)
101#endif
102
103#define BUFFER_LRU_MAX 64
104
105struct tree_entry {
106 u64 start;
107 u64 end;
108 struct rb_node rb_node;
109};
110
111struct extent_page_data {
112 struct bio *bio;
113 struct extent_io_tree *tree;
114 /* tells writepage not to lock the state bits for this range
115 * it still does the unlocking
116 */
117 unsigned int extent_locked:1;
118
119 /* tells the submit_bio code to use REQ_SYNC */
120 unsigned int sync_io:1;
121};
122
123static int add_extent_changeset(struct extent_state *state, unsigned bits,
124 struct extent_changeset *changeset,
125 int set)
126{
127 int ret;
128
129 if (!changeset)
130 return 0;
131 if (set && (state->state & bits) == bits)
132 return 0;
133 if (!set && (state->state & bits) == 0)
134 return 0;
135 changeset->bytes_changed += state->end - state->start + 1;
136 ret = ulist_add(&changeset->range_changed, state->start, state->end,
137 GFP_ATOMIC);
138 return ret;
139}
140
141static void flush_write_bio(struct extent_page_data *epd);
142
143static inline struct btrfs_fs_info *
144tree_fs_info(struct extent_io_tree *tree)
145{
146 if (tree->ops)
147 return tree->ops->tree_fs_info(tree->private_data);
148 return NULL;
149}
150
151int __init extent_io_init(void)
152{
153 extent_state_cache = kmem_cache_create("btrfs_extent_state",
154 sizeof(struct extent_state), 0,
155 SLAB_MEM_SPREAD, NULL);
156 if (!extent_state_cache)
157 return -ENOMEM;
158
159 extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
160 sizeof(struct extent_buffer), 0,
161 SLAB_MEM_SPREAD, NULL);
162 if (!extent_buffer_cache)
163 goto free_state_cache;
164
165 btrfs_bioset = bioset_create(BIO_POOL_SIZE,
166 offsetof(struct btrfs_io_bio, bio),
167 BIOSET_NEED_BVECS);
168 if (!btrfs_bioset)
169 goto free_buffer_cache;
170
171 if (bioset_integrity_create(btrfs_bioset, BIO_POOL_SIZE))
172 goto free_bioset;
173
174 return 0;
175
176free_bioset:
177 bioset_free(btrfs_bioset);
178 btrfs_bioset = NULL;
179
180free_buffer_cache:
181 kmem_cache_destroy(extent_buffer_cache);
182 extent_buffer_cache = NULL;
183
184free_state_cache:
185 kmem_cache_destroy(extent_state_cache);
186 extent_state_cache = NULL;
187 return -ENOMEM;
188}
189
190void __cold extent_io_exit(void)
191{
192 btrfs_leak_debug_check();
193
194 /*
195 * Make sure all delayed rcu free are flushed before we
196 * destroy caches.
197 */
198 rcu_barrier();
199 kmem_cache_destroy(extent_state_cache);
200 kmem_cache_destroy(extent_buffer_cache);
201 if (btrfs_bioset)
202 bioset_free(btrfs_bioset);
203}
204
205void extent_io_tree_init(struct extent_io_tree *tree,
206 void *private_data)
207{
208 tree->state = RB_ROOT;
209 tree->ops = NULL;
210 tree->dirty_bytes = 0;
211 spin_lock_init(&tree->lock);
212 tree->private_data = private_data;
213}
214
215static struct extent_state *alloc_extent_state(gfp_t mask)
216{
217 struct extent_state *state;
218
219 /*
220 * The given mask might be not appropriate for the slab allocator,
221 * drop the unsupported bits
222 */
223 mask &= ~(__GFP_DMA32|__GFP_HIGHMEM);
224 state = kmem_cache_alloc(extent_state_cache, mask);
225 if (!state)
226 return state;
227 state->state = 0;
228 state->failrec = NULL;
229 RB_CLEAR_NODE(&state->rb_node);
230 btrfs_leak_debug_add(&state->leak_list, &states);
231 refcount_set(&state->refs, 1);
232 init_waitqueue_head(&state->wq);
233 trace_alloc_extent_state(state, mask, _RET_IP_);
234 return state;
235}
236
237void free_extent_state(struct extent_state *state)
238{
239 if (!state)
240 return;
241 if (refcount_dec_and_test(&state->refs)) {
242 WARN_ON(extent_state_in_tree(state));
243 btrfs_leak_debug_del(&state->leak_list);
244 trace_free_extent_state(state, _RET_IP_);
245 kmem_cache_free(extent_state_cache, state);
246 }
247}
248
249static struct rb_node *tree_insert(struct rb_root *root,
250 struct rb_node *search_start,
251 u64 offset,
252 struct rb_node *node,
253 struct rb_node ***p_in,
254 struct rb_node **parent_in)
255{
256 struct rb_node **p;
257 struct rb_node *parent = NULL;
258 struct tree_entry *entry;
259
260 if (p_in && parent_in) {
261 p = *p_in;
262 parent = *parent_in;
263 goto do_insert;
264 }
265
266 p = search_start ? &search_start : &root->rb_node;
267 while (*p) {
268 parent = *p;
269 entry = rb_entry(parent, struct tree_entry, rb_node);
270
271 if (offset < entry->start)
272 p = &(*p)->rb_left;
273 else if (offset > entry->end)
274 p = &(*p)->rb_right;
275 else
276 return parent;
277 }
278
279do_insert:
280 rb_link_node(node, parent, p);
281 rb_insert_color(node, root);
282 return NULL;
283}
284
285static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
286 struct rb_node **prev_ret,
287 struct rb_node **next_ret,
288 struct rb_node ***p_ret,
289 struct rb_node **parent_ret)
290{
291 struct rb_root *root = &tree->state;
292 struct rb_node **n = &root->rb_node;
293 struct rb_node *prev = NULL;
294 struct rb_node *orig_prev = NULL;
295 struct tree_entry *entry;
296 struct tree_entry *prev_entry = NULL;
297
298 while (*n) {
299 prev = *n;
300 entry = rb_entry(prev, struct tree_entry, rb_node);
301 prev_entry = entry;
302
303 if (offset < entry->start)
304 n = &(*n)->rb_left;
305 else if (offset > entry->end)
306 n = &(*n)->rb_right;
307 else
308 return *n;
309 }
310
311 if (p_ret)
312 *p_ret = n;
313 if (parent_ret)
314 *parent_ret = prev;
315
316 if (prev_ret) {
317 orig_prev = prev;
318 while (prev && offset > prev_entry->end) {
319 prev = rb_next(prev);
320 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
321 }
322 *prev_ret = prev;
323 prev = orig_prev;
324 }
325
326 if (next_ret) {
327 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
328 while (prev && offset < prev_entry->start) {
329 prev = rb_prev(prev);
330 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
331 }
332 *next_ret = prev;
333 }
334 return NULL;
335}
336
337static inline struct rb_node *
338tree_search_for_insert(struct extent_io_tree *tree,
339 u64 offset,
340 struct rb_node ***p_ret,
341 struct rb_node **parent_ret)
342{
343 struct rb_node *prev = NULL;
344 struct rb_node *ret;
345
346 ret = __etree_search(tree, offset, &prev, NULL, p_ret, parent_ret);
347 if (!ret)
348 return prev;
349 return ret;
350}
351
352static inline struct rb_node *tree_search(struct extent_io_tree *tree,
353 u64 offset)
354{
355 return tree_search_for_insert(tree, offset, NULL, NULL);
356}
357
358static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
359 struct extent_state *other)
360{
361 if (tree->ops && tree->ops->merge_extent_hook)
362 tree->ops->merge_extent_hook(tree->private_data, new, other);
363}
364
365/*
366 * utility function to look for merge candidates inside a given range.
367 * Any extents with matching state are merged together into a single
368 * extent in the tree. Extents with EXTENT_IO in their state field
369 * are not merged because the end_io handlers need to be able to do
370 * operations on them without sleeping (or doing allocations/splits).
371 *
372 * This should be called with the tree lock held.
373 */
374static void merge_state(struct extent_io_tree *tree,
375 struct extent_state *state)
376{
377 struct extent_state *other;
378 struct rb_node *other_node;
379
380 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
381 return;
382
383 other_node = rb_prev(&state->rb_node);
384 if (other_node) {
385 other = rb_entry(other_node, struct extent_state, rb_node);
386 if (other->end == state->start - 1 &&
387 other->state == state->state) {
388 merge_cb(tree, state, other);
389 state->start = other->start;
390 rb_erase(&other->rb_node, &tree->state);
391 RB_CLEAR_NODE(&other->rb_node);
392 free_extent_state(other);
393 }
394 }
395 other_node = rb_next(&state->rb_node);
396 if (other_node) {
397 other = rb_entry(other_node, struct extent_state, rb_node);
398 if (other->start == state->end + 1 &&
399 other->state == state->state) {
400 merge_cb(tree, state, other);
401 state->end = other->end;
402 rb_erase(&other->rb_node, &tree->state);
403 RB_CLEAR_NODE(&other->rb_node);
404 free_extent_state(other);
405 }
406 }
407}
408
409static void set_state_cb(struct extent_io_tree *tree,
410 struct extent_state *state, unsigned *bits)
411{
412 if (tree->ops && tree->ops->set_bit_hook)
413 tree->ops->set_bit_hook(tree->private_data, state, bits);
414}
415
416static void clear_state_cb(struct extent_io_tree *tree,
417 struct extent_state *state, unsigned *bits)
418{
419 if (tree->ops && tree->ops->clear_bit_hook)
420 tree->ops->clear_bit_hook(tree->private_data, state, bits);
421}
422
423static void set_state_bits(struct extent_io_tree *tree,
424 struct extent_state *state, unsigned *bits,
425 struct extent_changeset *changeset);
426
427/*
428 * insert an extent_state struct into the tree. 'bits' are set on the
429 * struct before it is inserted.
430 *
431 * This may return -EEXIST if the extent is already there, in which case the
432 * state struct is freed.
433 *
434 * The tree lock is not taken internally. This is a utility function and
435 * probably isn't what you want to call (see set/clear_extent_bit).
436 */
437static int insert_state(struct extent_io_tree *tree,
438 struct extent_state *state, u64 start, u64 end,
439 struct rb_node ***p,
440 struct rb_node **parent,
441 unsigned *bits, struct extent_changeset *changeset)
442{
443 struct rb_node *node;
444
445 if (end < start)
446 WARN(1, KERN_ERR "BTRFS: end < start %llu %llu\n",
447 end, start);
448 state->start = start;
449 state->end = end;
450
451 set_state_bits(tree, state, bits, changeset);
452
453 node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
454 if (node) {
455 struct extent_state *found;
456 found = rb_entry(node, struct extent_state, rb_node);
457 pr_err("BTRFS: found node %llu %llu on insert of %llu %llu\n",
458 found->start, found->end, start, end);
459 return -EEXIST;
460 }
461 merge_state(tree, state);
462 return 0;
463}
464
465static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
466 u64 split)
467{
468 if (tree->ops && tree->ops->split_extent_hook)
469 tree->ops->split_extent_hook(tree->private_data, orig, split);
470}
471
472/*
473 * split a given extent state struct in two, inserting the preallocated
474 * struct 'prealloc' as the newly created second half. 'split' indicates an
475 * offset inside 'orig' where it should be split.
476 *
477 * Before calling,
478 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
479 * are two extent state structs in the tree:
480 * prealloc: [orig->start, split - 1]
481 * orig: [ split, orig->end ]
482 *
483 * The tree locks are not taken by this function. They need to be held
484 * by the caller.
485 */
486static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
487 struct extent_state *prealloc, u64 split)
488{
489 struct rb_node *node;
490
491 split_cb(tree, orig, split);
492
493 prealloc->start = orig->start;
494 prealloc->end = split - 1;
495 prealloc->state = orig->state;
496 orig->start = split;
497
498 node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
499 &prealloc->rb_node, NULL, NULL);
500 if (node) {
501 free_extent_state(prealloc);
502 return -EEXIST;
503 }
504 return 0;
505}
506
507static struct extent_state *next_state(struct extent_state *state)
508{
509 struct rb_node *next = rb_next(&state->rb_node);
510 if (next)
511 return rb_entry(next, struct extent_state, rb_node);
512 else
513 return NULL;
514}
515
516/*
517 * utility function to clear some bits in an extent state struct.
518 * it will optionally wake up any one waiting on this state (wake == 1).
519 *
520 * If no bits are set on the state struct after clearing things, the
521 * struct is freed and removed from the tree
522 */
523static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
524 struct extent_state *state,
525 unsigned *bits, int wake,
526 struct extent_changeset *changeset)
527{
528 struct extent_state *next;
529 unsigned bits_to_clear = *bits & ~EXTENT_CTLBITS;
530 int ret;
531
532 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
533 u64 range = state->end - state->start + 1;
534 WARN_ON(range > tree->dirty_bytes);
535 tree->dirty_bytes -= range;
536 }
537 clear_state_cb(tree, state, bits);
538 ret = add_extent_changeset(state, bits_to_clear, changeset, 0);
539 BUG_ON(ret < 0);
540 state->state &= ~bits_to_clear;
541 if (wake)
542 wake_up(&state->wq);
543 if (state->state == 0) {
544 next = next_state(state);
545 if (extent_state_in_tree(state)) {
546 rb_erase(&state->rb_node, &tree->state);
547 RB_CLEAR_NODE(&state->rb_node);
548 free_extent_state(state);
549 } else {
550 WARN_ON(1);
551 }
552 } else {
553 merge_state(tree, state);
554 next = next_state(state);
555 }
556 return next;
557}
558
559static struct extent_state *
560alloc_extent_state_atomic(struct extent_state *prealloc)
561{
562 if (!prealloc)
563 prealloc = alloc_extent_state(GFP_ATOMIC);
564
565 return prealloc;
566}
567
568static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
569{
570 btrfs_panic(tree_fs_info(tree), err,
571 "Locking error: Extent tree was modified by another thread while locked.");
572}
573
574/*
575 * clear some bits on a range in the tree. This may require splitting
576 * or inserting elements in the tree, so the gfp mask is used to
577 * indicate which allocations or sleeping are allowed.
578 *
579 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
580 * the given range from the tree regardless of state (ie for truncate).
581 *
582 * the range [start, end] is inclusive.
583 *
584 * This takes the tree lock, and returns 0 on success and < 0 on error.
585 */
586int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
587 unsigned bits, int wake, int delete,
588 struct extent_state **cached_state,
589 gfp_t mask, struct extent_changeset *changeset)
590{
591 struct extent_state *state;
592 struct extent_state *cached;
593 struct extent_state *prealloc = NULL;
594 struct rb_node *node;
595 u64 last_end;
596 int err;
597 int clear = 0;
598
599 btrfs_debug_check_extent_io_range(tree, start, end);
600
601 if (bits & EXTENT_DELALLOC)
602 bits |= EXTENT_NORESERVE;
603
604 if (delete)
605 bits |= ~EXTENT_CTLBITS;
606 bits |= EXTENT_FIRST_DELALLOC;
607
608 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
609 clear = 1;
610again:
611 if (!prealloc && gfpflags_allow_blocking(mask)) {
612 /*
613 * Don't care for allocation failure here because we might end
614 * up not needing the pre-allocated extent state at all, which
615 * is the case if we only have in the tree extent states that
616 * cover our input range and don't cover too any other range.
617 * If we end up needing a new extent state we allocate it later.
618 */
619 prealloc = alloc_extent_state(mask);
620 }
621
622 spin_lock(&tree->lock);
623 if (cached_state) {
624 cached = *cached_state;
625
626 if (clear) {
627 *cached_state = NULL;
628 cached_state = NULL;
629 }
630
631 if (cached && extent_state_in_tree(cached) &&
632 cached->start <= start && cached->end > start) {
633 if (clear)
634 refcount_dec(&cached->refs);
635 state = cached;
636 goto hit_next;
637 }
638 if (clear)
639 free_extent_state(cached);
640 }
641 /*
642 * this search will find the extents that end after
643 * our range starts
644 */
645 node = tree_search(tree, start);
646 if (!node)
647 goto out;
648 state = rb_entry(node, struct extent_state, rb_node);
649hit_next:
650 if (state->start > end)
651 goto out;
652 WARN_ON(state->end < start);
653 last_end = state->end;
654
655 /* the state doesn't have the wanted bits, go ahead */
656 if (!(state->state & bits)) {
657 state = next_state(state);
658 goto next;
659 }
660
661 /*
662 * | ---- desired range ---- |
663 * | state | or
664 * | ------------- state -------------- |
665 *
666 * We need to split the extent we found, and may flip
667 * bits on second half.
668 *
669 * If the extent we found extends past our range, we
670 * just split and search again. It'll get split again
671 * the next time though.
672 *
673 * If the extent we found is inside our range, we clear
674 * the desired bit on it.
675 */
676
677 if (state->start < start) {
678 prealloc = alloc_extent_state_atomic(prealloc);
679 BUG_ON(!prealloc);
680 err = split_state(tree, state, prealloc, start);
681 if (err)
682 extent_io_tree_panic(tree, err);
683
684 prealloc = NULL;
685 if (err)
686 goto out;
687 if (state->end <= end) {
688 state = clear_state_bit(tree, state, &bits, wake,
689 changeset);
690 goto next;
691 }
692 goto search_again;
693 }
694 /*
695 * | ---- desired range ---- |
696 * | state |
697 * We need to split the extent, and clear the bit
698 * on the first half
699 */
700 if (state->start <= end && state->end > end) {
701 prealloc = alloc_extent_state_atomic(prealloc);
702 BUG_ON(!prealloc);
703 err = split_state(tree, state, prealloc, end + 1);
704 if (err)
705 extent_io_tree_panic(tree, err);
706
707 if (wake)
708 wake_up(&state->wq);
709
710 clear_state_bit(tree, prealloc, &bits, wake, changeset);
711
712 prealloc = NULL;
713 goto out;
714 }
715
716 state = clear_state_bit(tree, state, &bits, wake, changeset);
717next:
718 if (last_end == (u64)-1)
719 goto out;
720 start = last_end + 1;
721 if (start <= end && state && !need_resched())
722 goto hit_next;
723
724search_again:
725 if (start > end)
726 goto out;
727 spin_unlock(&tree->lock);
728 if (gfpflags_allow_blocking(mask))
729 cond_resched();
730 goto again;
731
732out:
733 spin_unlock(&tree->lock);
734 if (prealloc)
735 free_extent_state(prealloc);
736
737 return 0;
738
739}
740
741static void wait_on_state(struct extent_io_tree *tree,
742 struct extent_state *state)
743 __releases(tree->lock)
744 __acquires(tree->lock)
745{
746 DEFINE_WAIT(wait);
747 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
748 spin_unlock(&tree->lock);
749 schedule();
750 spin_lock(&tree->lock);
751 finish_wait(&state->wq, &wait);
752}
753
754/*
755 * waits for one or more bits to clear on a range in the state tree.
756 * The range [start, end] is inclusive.
757 * The tree lock is taken by this function
758 */
759static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
760 unsigned long bits)
761{
762 struct extent_state *state;
763 struct rb_node *node;
764
765 btrfs_debug_check_extent_io_range(tree, start, end);
766
767 spin_lock(&tree->lock);
768again:
769 while (1) {
770 /*
771 * this search will find all the extents that end after
772 * our range starts
773 */
774 node = tree_search(tree, start);
775process_node:
776 if (!node)
777 break;
778
779 state = rb_entry(node, struct extent_state, rb_node);
780
781 if (state->start > end)
782 goto out;
783
784 if (state->state & bits) {
785 start = state->start;
786 refcount_inc(&state->refs);
787 wait_on_state(tree, state);
788 free_extent_state(state);
789 goto again;
790 }
791 start = state->end + 1;
792
793 if (start > end)
794 break;
795
796 if (!cond_resched_lock(&tree->lock)) {
797 node = rb_next(node);
798 goto process_node;
799 }
800 }
801out:
802 spin_unlock(&tree->lock);
803}
804
805static void set_state_bits(struct extent_io_tree *tree,
806 struct extent_state *state,
807 unsigned *bits, struct extent_changeset *changeset)
808{
809 unsigned bits_to_set = *bits & ~EXTENT_CTLBITS;
810 int ret;
811
812 set_state_cb(tree, state, bits);
813 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
814 u64 range = state->end - state->start + 1;
815 tree->dirty_bytes += range;
816 }
817 ret = add_extent_changeset(state, bits_to_set, changeset, 1);
818 BUG_ON(ret < 0);
819 state->state |= bits_to_set;
820}
821
822static void cache_state_if_flags(struct extent_state *state,
823 struct extent_state **cached_ptr,
824 unsigned flags)
825{
826 if (cached_ptr && !(*cached_ptr)) {
827 if (!flags || (state->state & flags)) {
828 *cached_ptr = state;
829 refcount_inc(&state->refs);
830 }
831 }
832}
833
834static void cache_state(struct extent_state *state,
835 struct extent_state **cached_ptr)
836{
837 return cache_state_if_flags(state, cached_ptr,
838 EXTENT_IOBITS | EXTENT_BOUNDARY);
839}
840
841/*
842 * set some bits on a range in the tree. This may require allocations or
843 * sleeping, so the gfp mask is used to indicate what is allowed.
844 *
845 * If any of the exclusive bits are set, this will fail with -EEXIST if some
846 * part of the range already has the desired bits set. The start of the
847 * existing range is returned in failed_start in this case.
848 *
849 * [start, end] is inclusive This takes the tree lock.
850 */
851
852static int __must_check
853__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
854 unsigned bits, unsigned exclusive_bits,
855 u64 *failed_start, struct extent_state **cached_state,
856 gfp_t mask, struct extent_changeset *changeset)
857{
858 struct extent_state *state;
859 struct extent_state *prealloc = NULL;
860 struct rb_node *node;
861 struct rb_node **p;
862 struct rb_node *parent;
863 int err = 0;
864 u64 last_start;
865 u64 last_end;
866
867 btrfs_debug_check_extent_io_range(tree, start, end);
868
869 bits |= EXTENT_FIRST_DELALLOC;
870again:
871 if (!prealloc && gfpflags_allow_blocking(mask)) {
872 /*
873 * Don't care for allocation failure here because we might end
874 * up not needing the pre-allocated extent state at all, which
875 * is the case if we only have in the tree extent states that
876 * cover our input range and don't cover too any other range.
877 * If we end up needing a new extent state we allocate it later.
878 */
879 prealloc = alloc_extent_state(mask);
880 }
881
882 spin_lock(&tree->lock);
883 if (cached_state && *cached_state) {
884 state = *cached_state;
885 if (state->start <= start && state->end > start &&
886 extent_state_in_tree(state)) {
887 node = &state->rb_node;
888 goto hit_next;
889 }
890 }
891 /*
892 * this search will find all the extents that end after
893 * our range starts.
894 */
895 node = tree_search_for_insert(tree, start, &p, &parent);
896 if (!node) {
897 prealloc = alloc_extent_state_atomic(prealloc);
898 BUG_ON(!prealloc);
899 err = insert_state(tree, prealloc, start, end,
900 &p, &parent, &bits, changeset);
901 if (err)
902 extent_io_tree_panic(tree, err);
903
904 cache_state(prealloc, cached_state);
905 prealloc = NULL;
906 goto out;
907 }
908 state = rb_entry(node, struct extent_state, rb_node);
909hit_next:
910 last_start = state->start;
911 last_end = state->end;
912
913 /*
914 * | ---- desired range ---- |
915 * | state |
916 *
917 * Just lock what we found and keep going
918 */
919 if (state->start == start && state->end <= end) {
920 if (state->state & exclusive_bits) {
921 *failed_start = state->start;
922 err = -EEXIST;
923 goto out;
924 }
925
926 set_state_bits(tree, state, &bits, changeset);
927 cache_state(state, cached_state);
928 merge_state(tree, state);
929 if (last_end == (u64)-1)
930 goto out;
931 start = last_end + 1;
932 state = next_state(state);
933 if (start < end && state && state->start == start &&
934 !need_resched())
935 goto hit_next;
936 goto search_again;
937 }
938
939 /*
940 * | ---- desired range ---- |
941 * | state |
942 * or
943 * | ------------- state -------------- |
944 *
945 * We need to split the extent we found, and may flip bits on
946 * second half.
947 *
948 * If the extent we found extends past our
949 * range, we just split and search again. It'll get split
950 * again the next time though.
951 *
952 * If the extent we found is inside our range, we set the
953 * desired bit on it.
954 */
955 if (state->start < start) {
956 if (state->state & exclusive_bits) {
957 *failed_start = start;
958 err = -EEXIST;
959 goto out;
960 }
961
962 prealloc = alloc_extent_state_atomic(prealloc);
963 BUG_ON(!prealloc);
964 err = split_state(tree, state, prealloc, start);
965 if (err)
966 extent_io_tree_panic(tree, err);
967
968 prealloc = NULL;
969 if (err)
970 goto out;
971 if (state->end <= end) {
972 set_state_bits(tree, state, &bits, changeset);
973 cache_state(state, cached_state);
974 merge_state(tree, state);
975 if (last_end == (u64)-1)
976 goto out;
977 start = last_end + 1;
978 state = next_state(state);
979 if (start < end && state && state->start == start &&
980 !need_resched())
981 goto hit_next;
982 }
983 goto search_again;
984 }
985 /*
986 * | ---- desired range ---- |
987 * | state | or | state |
988 *
989 * There's a hole, we need to insert something in it and
990 * ignore the extent we found.
991 */
992 if (state->start > start) {
993 u64 this_end;
994 if (end < last_start)
995 this_end = end;
996 else
997 this_end = last_start - 1;
998
999 prealloc = alloc_extent_state_atomic(prealloc);
1000 BUG_ON(!prealloc);
1001
1002 /*
1003 * Avoid to free 'prealloc' if it can be merged with
1004 * the later extent.
1005 */
1006 err = insert_state(tree, prealloc, start, this_end,
1007 NULL, NULL, &bits, changeset);
1008 if (err)
1009 extent_io_tree_panic(tree, err);
1010
1011 cache_state(prealloc, cached_state);
1012 prealloc = NULL;
1013 start = this_end + 1;
1014 goto search_again;
1015 }
1016 /*
1017 * | ---- desired range ---- |
1018 * | state |
1019 * We need to split the extent, and set the bit
1020 * on the first half
1021 */
1022 if (state->start <= end && state->end > end) {
1023 if (state->state & exclusive_bits) {
1024 *failed_start = start;
1025 err = -EEXIST;
1026 goto out;
1027 }
1028
1029 prealloc = alloc_extent_state_atomic(prealloc);
1030 BUG_ON(!prealloc);
1031 err = split_state(tree, state, prealloc, end + 1);
1032 if (err)
1033 extent_io_tree_panic(tree, err);
1034
1035 set_state_bits(tree, prealloc, &bits, changeset);
1036 cache_state(prealloc, cached_state);
1037 merge_state(tree, prealloc);
1038 prealloc = NULL;
1039 goto out;
1040 }
1041
1042search_again:
1043 if (start > end)
1044 goto out;
1045 spin_unlock(&tree->lock);
1046 if (gfpflags_allow_blocking(mask))
1047 cond_resched();
1048 goto again;
1049
1050out:
1051 spin_unlock(&tree->lock);
1052 if (prealloc)
1053 free_extent_state(prealloc);
1054
1055 return err;
1056
1057}
1058
1059int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1060 unsigned bits, u64 * failed_start,
1061 struct extent_state **cached_state, gfp_t mask)
1062{
1063 return __set_extent_bit(tree, start, end, bits, 0, failed_start,
1064 cached_state, mask, NULL);
1065}
1066
1067
1068/**
1069 * convert_extent_bit - convert all bits in a given range from one bit to
1070 * another
1071 * @tree: the io tree to search
1072 * @start: the start offset in bytes
1073 * @end: the end offset in bytes (inclusive)
1074 * @bits: the bits to set in this range
1075 * @clear_bits: the bits to clear in this range
1076 * @cached_state: state that we're going to cache
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 *
1084 * All allocations are done with GFP_NOFS.
1085 */
1086int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1087 unsigned bits, unsigned clear_bits,
1088 struct extent_state **cached_state)
1089{
1090 struct extent_state *state;
1091 struct extent_state *prealloc = NULL;
1092 struct rb_node *node;
1093 struct rb_node **p;
1094 struct rb_node *parent;
1095 int err = 0;
1096 u64 last_start;
1097 u64 last_end;
1098 bool first_iteration = true;
1099
1100 btrfs_debug_check_extent_io_range(tree, start, end);
1101
1102again:
1103 if (!prealloc) {
1104 /*
1105 * Best effort, don't worry if extent state allocation fails
1106 * here for the first iteration. We might have a cached state
1107 * that matches exactly the target range, in which case no
1108 * extent state allocations are needed. We'll only know this
1109 * after locking the tree.
1110 */
1111 prealloc = alloc_extent_state(GFP_NOFS);
1112 if (!prealloc && !first_iteration)
1113 return -ENOMEM;
1114 }
1115
1116 spin_lock(&tree->lock);
1117 if (cached_state && *cached_state) {
1118 state = *cached_state;
1119 if (state->start <= start && state->end > start &&
1120 extent_state_in_tree(state)) {
1121 node = &state->rb_node;
1122 goto hit_next;
1123 }
1124 }
1125
1126 /*
1127 * this search will find all the extents that end after
1128 * our range starts.
1129 */
1130 node = tree_search_for_insert(tree, start, &p, &parent);
1131 if (!node) {
1132 prealloc = alloc_extent_state_atomic(prealloc);
1133 if (!prealloc) {
1134 err = -ENOMEM;
1135 goto out;
1136 }
1137 err = insert_state(tree, prealloc, start, end,
1138 &p, &parent, &bits, NULL);
1139 if (err)
1140 extent_io_tree_panic(tree, err);
1141 cache_state(prealloc, cached_state);
1142 prealloc = NULL;
1143 goto out;
1144 }
1145 state = rb_entry(node, struct extent_state, rb_node);
1146hit_next:
1147 last_start = state->start;
1148 last_end = state->end;
1149
1150 /*
1151 * | ---- desired range ---- |
1152 * | state |
1153 *
1154 * Just lock what we found and keep going
1155 */
1156 if (state->start == start && state->end <= end) {
1157 set_state_bits(tree, state, &bits, NULL);
1158 cache_state(state, cached_state);
1159 state = clear_state_bit(tree, state, &clear_bits, 0, NULL);
1160 if (last_end == (u64)-1)
1161 goto out;
1162 start = last_end + 1;
1163 if (start < end && state && state->start == start &&
1164 !need_resched())
1165 goto hit_next;
1166 goto search_again;
1167 }
1168
1169 /*
1170 * | ---- desired range ---- |
1171 * | state |
1172 * or
1173 * | ------------- state -------------- |
1174 *
1175 * We need to split the extent we found, and may flip bits on
1176 * second half.
1177 *
1178 * If the extent we found extends past our
1179 * range, we just split and search again. It'll get split
1180 * again the next time though.
1181 *
1182 * If the extent we found is inside our range, we set the
1183 * desired bit on it.
1184 */
1185 if (state->start < start) {
1186 prealloc = alloc_extent_state_atomic(prealloc);
1187 if (!prealloc) {
1188 err = -ENOMEM;
1189 goto out;
1190 }
1191 err = split_state(tree, state, prealloc, start);
1192 if (err)
1193 extent_io_tree_panic(tree, err);
1194 prealloc = NULL;
1195 if (err)
1196 goto out;
1197 if (state->end <= end) {
1198 set_state_bits(tree, state, &bits, NULL);
1199 cache_state(state, cached_state);
1200 state = clear_state_bit(tree, state, &clear_bits, 0,
1201 NULL);
1202 if (last_end == (u64)-1)
1203 goto out;
1204 start = last_end + 1;
1205 if (start < end && state && state->start == start &&
1206 !need_resched())
1207 goto hit_next;
1208 }
1209 goto search_again;
1210 }
1211 /*
1212 * | ---- desired range ---- |
1213 * | state | or | state |
1214 *
1215 * There's a hole, we need to insert something in it and
1216 * ignore the extent we found.
1217 */
1218 if (state->start > start) {
1219 u64 this_end;
1220 if (end < last_start)
1221 this_end = end;
1222 else
1223 this_end = last_start - 1;
1224
1225 prealloc = alloc_extent_state_atomic(prealloc);
1226 if (!prealloc) {
1227 err = -ENOMEM;
1228 goto out;
1229 }
1230
1231 /*
1232 * Avoid to free 'prealloc' if it can be merged with
1233 * the later extent.
1234 */
1235 err = insert_state(tree, prealloc, start, this_end,
1236 NULL, NULL, &bits, NULL);
1237 if (err)
1238 extent_io_tree_panic(tree, err);
1239 cache_state(prealloc, cached_state);
1240 prealloc = NULL;
1241 start = this_end + 1;
1242 goto search_again;
1243 }
1244 /*
1245 * | ---- desired range ---- |
1246 * | state |
1247 * We need to split the extent, and set the bit
1248 * on the first half
1249 */
1250 if (state->start <= end && state->end > end) {
1251 prealloc = alloc_extent_state_atomic(prealloc);
1252 if (!prealloc) {
1253 err = -ENOMEM;
1254 goto out;
1255 }
1256
1257 err = split_state(tree, state, prealloc, end + 1);
1258 if (err)
1259 extent_io_tree_panic(tree, err);
1260
1261 set_state_bits(tree, prealloc, &bits, NULL);
1262 cache_state(prealloc, cached_state);
1263 clear_state_bit(tree, prealloc, &clear_bits, 0, NULL);
1264 prealloc = NULL;
1265 goto out;
1266 }
1267
1268search_again:
1269 if (start > end)
1270 goto out;
1271 spin_unlock(&tree->lock);
1272 cond_resched();
1273 first_iteration = false;
1274 goto again;
1275
1276out:
1277 spin_unlock(&tree->lock);
1278 if (prealloc)
1279 free_extent_state(prealloc);
1280
1281 return err;
1282}
1283
1284/* wrappers around set/clear extent bit */
1285int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1286 unsigned bits, struct extent_changeset *changeset)
1287{
1288 /*
1289 * We don't support EXTENT_LOCKED yet, as current changeset will
1290 * record any bits changed, so for EXTENT_LOCKED case, it will
1291 * either fail with -EEXIST or changeset will record the whole
1292 * range.
1293 */
1294 BUG_ON(bits & EXTENT_LOCKED);
1295
1296 return __set_extent_bit(tree, start, end, bits, 0, NULL, NULL, GFP_NOFS,
1297 changeset);
1298}
1299
1300int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1301 unsigned bits, int wake, int delete,
1302 struct extent_state **cached)
1303{
1304 return __clear_extent_bit(tree, start, end, bits, wake, delete,
1305 cached, GFP_NOFS, NULL);
1306}
1307
1308int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1309 unsigned bits, struct extent_changeset *changeset)
1310{
1311 /*
1312 * Don't support EXTENT_LOCKED case, same reason as
1313 * set_record_extent_bits().
1314 */
1315 BUG_ON(bits & EXTENT_LOCKED);
1316
1317 return __clear_extent_bit(tree, start, end, bits, 0, 0, NULL, GFP_NOFS,
1318 changeset);
1319}
1320
1321/*
1322 * either insert or lock state struct between start and end use mask to tell
1323 * us if waiting is desired.
1324 */
1325int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1326 struct extent_state **cached_state)
1327{
1328 int err;
1329 u64 failed_start;
1330
1331 while (1) {
1332 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED,
1333 EXTENT_LOCKED, &failed_start,
1334 cached_state, GFP_NOFS, NULL);
1335 if (err == -EEXIST) {
1336 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
1337 start = failed_start;
1338 } else
1339 break;
1340 WARN_ON(start > end);
1341 }
1342 return err;
1343}
1344
1345int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1346{
1347 int err;
1348 u64 failed_start;
1349
1350 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1351 &failed_start, NULL, GFP_NOFS, NULL);
1352 if (err == -EEXIST) {
1353 if (failed_start > start)
1354 clear_extent_bit(tree, start, failed_start - 1,
1355 EXTENT_LOCKED, 1, 0, NULL);
1356 return 0;
1357 }
1358 return 1;
1359}
1360
1361void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
1362{
1363 unsigned long index = start >> PAGE_SHIFT;
1364 unsigned long end_index = end >> PAGE_SHIFT;
1365 struct page *page;
1366
1367 while (index <= end_index) {
1368 page = find_get_page(inode->i_mapping, index);
1369 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1370 clear_page_dirty_for_io(page);
1371 put_page(page);
1372 index++;
1373 }
1374}
1375
1376void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
1377{
1378 unsigned long index = start >> PAGE_SHIFT;
1379 unsigned long end_index = end >> PAGE_SHIFT;
1380 struct page *page;
1381
1382 while (index <= end_index) {
1383 page = find_get_page(inode->i_mapping, index);
1384 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1385 __set_page_dirty_nobuffers(page);
1386 account_page_redirty(page);
1387 put_page(page);
1388 index++;
1389 }
1390}
1391
1392/*
1393 * helper function to set both pages and extents in the tree writeback
1394 */
1395static void set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1396{
1397 tree->ops->set_range_writeback(tree->private_data, start, end);
1398}
1399
1400/* find the first state struct with 'bits' set after 'start', and
1401 * return it. tree->lock must be held. NULL will returned if
1402 * nothing was found after 'start'
1403 */
1404static struct extent_state *
1405find_first_extent_bit_state(struct extent_io_tree *tree,
1406 u64 start, unsigned bits)
1407{
1408 struct rb_node *node;
1409 struct extent_state *state;
1410
1411 /*
1412 * this search will find all the extents that end after
1413 * our range starts.
1414 */
1415 node = tree_search(tree, start);
1416 if (!node)
1417 goto out;
1418
1419 while (1) {
1420 state = rb_entry(node, struct extent_state, rb_node);
1421 if (state->end >= start && (state->state & bits))
1422 return state;
1423
1424 node = rb_next(node);
1425 if (!node)
1426 break;
1427 }
1428out:
1429 return NULL;
1430}
1431
1432/*
1433 * find the first offset in the io tree with 'bits' set. zero is
1434 * returned if we find something, and *start_ret and *end_ret are
1435 * set to reflect the state struct that was found.
1436 *
1437 * If nothing was found, 1 is returned. If found something, return 0.
1438 */
1439int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1440 u64 *start_ret, u64 *end_ret, unsigned bits,
1441 struct extent_state **cached_state)
1442{
1443 struct extent_state *state;
1444 struct rb_node *n;
1445 int ret = 1;
1446
1447 spin_lock(&tree->lock);
1448 if (cached_state && *cached_state) {
1449 state = *cached_state;
1450 if (state->end == start - 1 && extent_state_in_tree(state)) {
1451 n = rb_next(&state->rb_node);
1452 while (n) {
1453 state = rb_entry(n, struct extent_state,
1454 rb_node);
1455 if (state->state & bits)
1456 goto got_it;
1457 n = rb_next(n);
1458 }
1459 free_extent_state(*cached_state);
1460 *cached_state = NULL;
1461 goto out;
1462 }
1463 free_extent_state(*cached_state);
1464 *cached_state = NULL;
1465 }
1466
1467 state = find_first_extent_bit_state(tree, start, bits);
1468got_it:
1469 if (state) {
1470 cache_state_if_flags(state, cached_state, 0);
1471 *start_ret = state->start;
1472 *end_ret = state->end;
1473 ret = 0;
1474 }
1475out:
1476 spin_unlock(&tree->lock);
1477 return ret;
1478}
1479
1480/*
1481 * find a contiguous range of bytes in the file marked as delalloc, not
1482 * more than 'max_bytes'. start and end are used to return the range,
1483 *
1484 * 1 is returned if we find something, 0 if nothing was in the tree
1485 */
1486static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1487 u64 *start, u64 *end, u64 max_bytes,
1488 struct extent_state **cached_state)
1489{
1490 struct rb_node *node;
1491 struct extent_state *state;
1492 u64 cur_start = *start;
1493 u64 found = 0;
1494 u64 total_bytes = 0;
1495
1496 spin_lock(&tree->lock);
1497
1498 /*
1499 * this search will find all the extents that end after
1500 * our range starts.
1501 */
1502 node = tree_search(tree, cur_start);
1503 if (!node) {
1504 if (!found)
1505 *end = (u64)-1;
1506 goto out;
1507 }
1508
1509 while (1) {
1510 state = rb_entry(node, struct extent_state, rb_node);
1511 if (found && (state->start != cur_start ||
1512 (state->state & EXTENT_BOUNDARY))) {
1513 goto out;
1514 }
1515 if (!(state->state & EXTENT_DELALLOC)) {
1516 if (!found)
1517 *end = state->end;
1518 goto out;
1519 }
1520 if (!found) {
1521 *start = state->start;
1522 *cached_state = state;
1523 refcount_inc(&state->refs);
1524 }
1525 found++;
1526 *end = state->end;
1527 cur_start = state->end + 1;
1528 node = rb_next(node);
1529 total_bytes += state->end - state->start + 1;
1530 if (total_bytes >= max_bytes)
1531 break;
1532 if (!node)
1533 break;
1534 }
1535out:
1536 spin_unlock(&tree->lock);
1537 return found;
1538}
1539
1540static int __process_pages_contig(struct address_space *mapping,
1541 struct page *locked_page,
1542 pgoff_t start_index, pgoff_t end_index,
1543 unsigned long page_ops, pgoff_t *index_ret);
1544
1545static noinline void __unlock_for_delalloc(struct inode *inode,
1546 struct page *locked_page,
1547 u64 start, u64 end)
1548{
1549 unsigned long index = start >> PAGE_SHIFT;
1550 unsigned long end_index = end >> PAGE_SHIFT;
1551
1552 ASSERT(locked_page);
1553 if (index == locked_page->index && end_index == index)
1554 return;
1555
1556 __process_pages_contig(inode->i_mapping, locked_page, index, end_index,
1557 PAGE_UNLOCK, NULL);
1558}
1559
1560static noinline int lock_delalloc_pages(struct inode *inode,
1561 struct page *locked_page,
1562 u64 delalloc_start,
1563 u64 delalloc_end)
1564{
1565 unsigned long index = delalloc_start >> PAGE_SHIFT;
1566 unsigned long index_ret = index;
1567 unsigned long end_index = delalloc_end >> PAGE_SHIFT;
1568 int ret;
1569
1570 ASSERT(locked_page);
1571 if (index == locked_page->index && index == end_index)
1572 return 0;
1573
1574 ret = __process_pages_contig(inode->i_mapping, locked_page, index,
1575 end_index, PAGE_LOCK, &index_ret);
1576 if (ret == -EAGAIN)
1577 __unlock_for_delalloc(inode, locked_page, delalloc_start,
1578 (u64)index_ret << PAGE_SHIFT);
1579 return ret;
1580}
1581
1582/*
1583 * find a contiguous range of bytes in the file marked as delalloc, not
1584 * more than 'max_bytes'. start and end are used to return the range,
1585 *
1586 * 1 is returned if we find something, 0 if nothing was in the tree
1587 */
1588STATIC u64 find_lock_delalloc_range(struct inode *inode,
1589 struct extent_io_tree *tree,
1590 struct page *locked_page, u64 *start,
1591 u64 *end, u64 max_bytes)
1592{
1593 u64 delalloc_start;
1594 u64 delalloc_end;
1595 u64 found;
1596 struct extent_state *cached_state = NULL;
1597 int ret;
1598 int loops = 0;
1599
1600again:
1601 /* step one, find a bunch of delalloc bytes starting at start */
1602 delalloc_start = *start;
1603 delalloc_end = 0;
1604 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1605 max_bytes, &cached_state);
1606 if (!found || delalloc_end <= *start) {
1607 *start = delalloc_start;
1608 *end = delalloc_end;
1609 free_extent_state(cached_state);
1610 return 0;
1611 }
1612
1613 /*
1614 * start comes from the offset of locked_page. We have to lock
1615 * pages in order, so we can't process delalloc bytes before
1616 * locked_page
1617 */
1618 if (delalloc_start < *start)
1619 delalloc_start = *start;
1620
1621 /*
1622 * make sure to limit the number of pages we try to lock down
1623 */
1624 if (delalloc_end + 1 - delalloc_start > max_bytes)
1625 delalloc_end = delalloc_start + max_bytes - 1;
1626
1627 /* step two, lock all the pages after the page that has start */
1628 ret = lock_delalloc_pages(inode, locked_page,
1629 delalloc_start, delalloc_end);
1630 if (ret == -EAGAIN) {
1631 /* some of the pages are gone, lets avoid looping by
1632 * shortening the size of the delalloc range we're searching
1633 */
1634 free_extent_state(cached_state);
1635 cached_state = NULL;
1636 if (!loops) {
1637 max_bytes = PAGE_SIZE;
1638 loops = 1;
1639 goto again;
1640 } else {
1641 found = 0;
1642 goto out_failed;
1643 }
1644 }
1645 BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
1646
1647 /* step three, lock the state bits for the whole range */
1648 lock_extent_bits(tree, delalloc_start, delalloc_end, &cached_state);
1649
1650 /* then test to make sure it is all still delalloc */
1651 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1652 EXTENT_DELALLOC, 1, cached_state);
1653 if (!ret) {
1654 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1655 &cached_state);
1656 __unlock_for_delalloc(inode, locked_page,
1657 delalloc_start, delalloc_end);
1658 cond_resched();
1659 goto again;
1660 }
1661 free_extent_state(cached_state);
1662 *start = delalloc_start;
1663 *end = delalloc_end;
1664out_failed:
1665 return found;
1666}
1667
1668static int __process_pages_contig(struct address_space *mapping,
1669 struct page *locked_page,
1670 pgoff_t start_index, pgoff_t end_index,
1671 unsigned long page_ops, pgoff_t *index_ret)
1672{
1673 unsigned long nr_pages = end_index - start_index + 1;
1674 unsigned long pages_locked = 0;
1675 pgoff_t index = start_index;
1676 struct page *pages[16];
1677 unsigned ret;
1678 int err = 0;
1679 int i;
1680
1681 if (page_ops & PAGE_LOCK) {
1682 ASSERT(page_ops == PAGE_LOCK);
1683 ASSERT(index_ret && *index_ret == start_index);
1684 }
1685
1686 if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
1687 mapping_set_error(mapping, -EIO);
1688
1689 while (nr_pages > 0) {
1690 ret = find_get_pages_contig(mapping, index,
1691 min_t(unsigned long,
1692 nr_pages, ARRAY_SIZE(pages)), pages);
1693 if (ret == 0) {
1694 /*
1695 * Only if we're going to lock these pages,
1696 * can we find nothing at @index.
1697 */
1698 ASSERT(page_ops & PAGE_LOCK);
1699 err = -EAGAIN;
1700 goto out;
1701 }
1702
1703 for (i = 0; i < ret; i++) {
1704 if (page_ops & PAGE_SET_PRIVATE2)
1705 SetPagePrivate2(pages[i]);
1706
1707 if (pages[i] == locked_page) {
1708 put_page(pages[i]);
1709 pages_locked++;
1710 continue;
1711 }
1712 if (page_ops & PAGE_CLEAR_DIRTY)
1713 clear_page_dirty_for_io(pages[i]);
1714 if (page_ops & PAGE_SET_WRITEBACK)
1715 set_page_writeback(pages[i]);
1716 if (page_ops & PAGE_SET_ERROR)
1717 SetPageError(pages[i]);
1718 if (page_ops & PAGE_END_WRITEBACK)
1719 end_page_writeback(pages[i]);
1720 if (page_ops & PAGE_UNLOCK)
1721 unlock_page(pages[i]);
1722 if (page_ops & PAGE_LOCK) {
1723 lock_page(pages[i]);
1724 if (!PageDirty(pages[i]) ||
1725 pages[i]->mapping != mapping) {
1726 unlock_page(pages[i]);
1727 put_page(pages[i]);
1728 err = -EAGAIN;
1729 goto out;
1730 }
1731 }
1732 put_page(pages[i]);
1733 pages_locked++;
1734 }
1735 nr_pages -= ret;
1736 index += ret;
1737 cond_resched();
1738 }
1739out:
1740 if (err && index_ret)
1741 *index_ret = start_index + pages_locked - 1;
1742 return err;
1743}
1744
1745void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
1746 u64 delalloc_end, struct page *locked_page,
1747 unsigned clear_bits,
1748 unsigned long page_ops)
1749{
1750 clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, clear_bits, 1, 0,
1751 NULL);
1752
1753 __process_pages_contig(inode->i_mapping, locked_page,
1754 start >> PAGE_SHIFT, end >> PAGE_SHIFT,
1755 page_ops, NULL);
1756}
1757
1758/*
1759 * count the number of bytes in the tree that have a given bit(s)
1760 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1761 * cached. The total number found is returned.
1762 */
1763u64 count_range_bits(struct extent_io_tree *tree,
1764 u64 *start, u64 search_end, u64 max_bytes,
1765 unsigned bits, int contig)
1766{
1767 struct rb_node *node;
1768 struct extent_state *state;
1769 u64 cur_start = *start;
1770 u64 total_bytes = 0;
1771 u64 last = 0;
1772 int found = 0;
1773
1774 if (WARN_ON(search_end <= cur_start))
1775 return 0;
1776
1777 spin_lock(&tree->lock);
1778 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1779 total_bytes = tree->dirty_bytes;
1780 goto out;
1781 }
1782 /*
1783 * this search will find all the extents that end after
1784 * our range starts.
1785 */
1786 node = tree_search(tree, cur_start);
1787 if (!node)
1788 goto out;
1789
1790 while (1) {
1791 state = rb_entry(node, struct extent_state, rb_node);
1792 if (state->start > search_end)
1793 break;
1794 if (contig && found && state->start > last + 1)
1795 break;
1796 if (state->end >= cur_start && (state->state & bits) == bits) {
1797 total_bytes += min(search_end, state->end) + 1 -
1798 max(cur_start, state->start);
1799 if (total_bytes >= max_bytes)
1800 break;
1801 if (!found) {
1802 *start = max(cur_start, state->start);
1803 found = 1;
1804 }
1805 last = state->end;
1806 } else if (contig && found) {
1807 break;
1808 }
1809 node = rb_next(node);
1810 if (!node)
1811 break;
1812 }
1813out:
1814 spin_unlock(&tree->lock);
1815 return total_bytes;
1816}
1817
1818/*
1819 * set the private field for a given byte offset in the tree. If there isn't
1820 * an extent_state there already, this does nothing.
1821 */
1822static noinline int set_state_failrec(struct extent_io_tree *tree, u64 start,
1823 struct io_failure_record *failrec)
1824{
1825 struct rb_node *node;
1826 struct extent_state *state;
1827 int ret = 0;
1828
1829 spin_lock(&tree->lock);
1830 /*
1831 * this search will find all the extents that end after
1832 * our range starts.
1833 */
1834 node = tree_search(tree, start);
1835 if (!node) {
1836 ret = -ENOENT;
1837 goto out;
1838 }
1839 state = rb_entry(node, struct extent_state, rb_node);
1840 if (state->start != start) {
1841 ret = -ENOENT;
1842 goto out;
1843 }
1844 state->failrec = failrec;
1845out:
1846 spin_unlock(&tree->lock);
1847 return ret;
1848}
1849
1850static noinline int get_state_failrec(struct extent_io_tree *tree, u64 start,
1851 struct io_failure_record **failrec)
1852{
1853 struct rb_node *node;
1854 struct extent_state *state;
1855 int ret = 0;
1856
1857 spin_lock(&tree->lock);
1858 /*
1859 * this search will find all the extents that end after
1860 * our range starts.
1861 */
1862 node = tree_search(tree, start);
1863 if (!node) {
1864 ret = -ENOENT;
1865 goto out;
1866 }
1867 state = rb_entry(node, struct extent_state, rb_node);
1868 if (state->start != start) {
1869 ret = -ENOENT;
1870 goto out;
1871 }
1872 *failrec = state->failrec;
1873out:
1874 spin_unlock(&tree->lock);
1875 return ret;
1876}
1877
1878/*
1879 * searches a range in the state tree for a given mask.
1880 * If 'filled' == 1, this returns 1 only if every extent in the tree
1881 * has the bits set. Otherwise, 1 is returned if any bit in the
1882 * range is found set.
1883 */
1884int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1885 unsigned bits, int filled, struct extent_state *cached)
1886{
1887 struct extent_state *state = NULL;
1888 struct rb_node *node;
1889 int bitset = 0;
1890
1891 spin_lock(&tree->lock);
1892 if (cached && extent_state_in_tree(cached) && cached->start <= start &&
1893 cached->end > start)
1894 node = &cached->rb_node;
1895 else
1896 node = tree_search(tree, start);
1897 while (node && start <= end) {
1898 state = rb_entry(node, struct extent_state, rb_node);
1899
1900 if (filled && state->start > start) {
1901 bitset = 0;
1902 break;
1903 }
1904
1905 if (state->start > end)
1906 break;
1907
1908 if (state->state & bits) {
1909 bitset = 1;
1910 if (!filled)
1911 break;
1912 } else if (filled) {
1913 bitset = 0;
1914 break;
1915 }
1916
1917 if (state->end == (u64)-1)
1918 break;
1919
1920 start = state->end + 1;
1921 if (start > end)
1922 break;
1923 node = rb_next(node);
1924 if (!node) {
1925 if (filled)
1926 bitset = 0;
1927 break;
1928 }
1929 }
1930 spin_unlock(&tree->lock);
1931 return bitset;
1932}
1933
1934/*
1935 * helper function to set a given page up to date if all the
1936 * extents in the tree for that page are up to date
1937 */
1938static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1939{
1940 u64 start = page_offset(page);
1941 u64 end = start + PAGE_SIZE - 1;
1942 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1943 SetPageUptodate(page);
1944}
1945
1946int free_io_failure(struct extent_io_tree *failure_tree,
1947 struct extent_io_tree *io_tree,
1948 struct io_failure_record *rec)
1949{
1950 int ret;
1951 int err = 0;
1952
1953 set_state_failrec(failure_tree, rec->start, NULL);
1954 ret = clear_extent_bits(failure_tree, rec->start,
1955 rec->start + rec->len - 1,
1956 EXTENT_LOCKED | EXTENT_DIRTY);
1957 if (ret)
1958 err = ret;
1959
1960 ret = clear_extent_bits(io_tree, rec->start,
1961 rec->start + rec->len - 1,
1962 EXTENT_DAMAGED);
1963 if (ret && !err)
1964 err = ret;
1965
1966 kfree(rec);
1967 return err;
1968}
1969
1970/*
1971 * this bypasses the standard btrfs submit functions deliberately, as
1972 * the standard behavior is to write all copies in a raid setup. here we only
1973 * want to write the one bad copy. so we do the mapping for ourselves and issue
1974 * submit_bio directly.
1975 * to avoid any synchronization issues, wait for the data after writing, which
1976 * actually prevents the read that triggered the error from finishing.
1977 * currently, there can be no more than two copies of every data bit. thus,
1978 * exactly one rewrite is required.
1979 */
1980int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
1981 u64 length, u64 logical, struct page *page,
1982 unsigned int pg_offset, int mirror_num)
1983{
1984 struct bio *bio;
1985 struct btrfs_device *dev;
1986 u64 map_length = 0;
1987 u64 sector;
1988 struct btrfs_bio *bbio = NULL;
1989 int ret;
1990
1991 ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
1992 BUG_ON(!mirror_num);
1993
1994 bio = btrfs_io_bio_alloc(1);
1995 bio->bi_iter.bi_size = 0;
1996 map_length = length;
1997
1998 /*
1999 * Avoid races with device replace and make sure our bbio has devices
2000 * associated to its stripes that don't go away while we are doing the
2001 * read repair operation.
2002 */
2003 btrfs_bio_counter_inc_blocked(fs_info);
2004 if (btrfs_is_parity_mirror(fs_info, logical, length)) {
2005 /*
2006 * Note that we don't use BTRFS_MAP_WRITE because it's supposed
2007 * to update all raid stripes, but here we just want to correct
2008 * bad stripe, thus BTRFS_MAP_READ is abused to only get the bad
2009 * stripe's dev and sector.
2010 */
2011 ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
2012 &map_length, &bbio, 0);
2013 if (ret) {
2014 btrfs_bio_counter_dec(fs_info);
2015 bio_put(bio);
2016 return -EIO;
2017 }
2018 ASSERT(bbio->mirror_num == 1);
2019 } else {
2020 ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
2021 &map_length, &bbio, mirror_num);
2022 if (ret) {
2023 btrfs_bio_counter_dec(fs_info);
2024 bio_put(bio);
2025 return -EIO;
2026 }
2027 BUG_ON(mirror_num != bbio->mirror_num);
2028 }
2029
2030 sector = bbio->stripes[bbio->mirror_num - 1].physical >> 9;
2031 bio->bi_iter.bi_sector = sector;
2032 dev = bbio->stripes[bbio->mirror_num - 1].dev;
2033 btrfs_put_bbio(bbio);
2034 if (!dev || !dev->bdev ||
2035 !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
2036 btrfs_bio_counter_dec(fs_info);
2037 bio_put(bio);
2038 return -EIO;
2039 }
2040 bio_set_dev(bio, dev->bdev);
2041 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
2042 bio_add_page(bio, page, length, pg_offset);
2043
2044 if (btrfsic_submit_bio_wait(bio)) {
2045 /* try to remap that extent elsewhere? */
2046 btrfs_bio_counter_dec(fs_info);
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 ino, start,
2055 rcu_str_deref(dev->name), sector);
2056 btrfs_bio_counter_dec(fs_info);
2057 bio_put(bio);
2058 return 0;
2059}
2060
2061int repair_eb_io_failure(struct btrfs_fs_info *fs_info,
2062 struct extent_buffer *eb, int mirror_num)
2063{
2064 u64 start = eb->start;
2065 unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
2066 int ret = 0;
2067
2068 if (sb_rdonly(fs_info->sb))
2069 return -EROFS;
2070
2071 for (i = 0; i < num_pages; i++) {
2072 struct page *p = eb->pages[i];
2073
2074 ret = repair_io_failure(fs_info, 0, start, 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 btrfs_fs_info *fs_info,
2089 struct extent_io_tree *failure_tree,
2090 struct extent_io_tree *io_tree, u64 start,
2091 struct page *page, u64 ino, unsigned int pg_offset)
2092{
2093 u64 private;
2094 struct io_failure_record *failrec;
2095 struct extent_state *state;
2096 int num_copies;
2097 int ret;
2098
2099 private = 0;
2100 ret = count_range_bits(failure_tree, &private, (u64)-1, 1,
2101 EXTENT_DIRTY, 0);
2102 if (!ret)
2103 return 0;
2104
2105 ret = get_state_failrec(failure_tree, start, &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 btrfs_debug(fs_info,
2114 "clean_io_failure: freeing dummy error at %llu",
2115 failrec->start);
2116 goto out;
2117 }
2118 if (sb_rdonly(fs_info->sb))
2119 goto out;
2120
2121 spin_lock(&io_tree->lock);
2122 state = find_first_extent_bit_state(io_tree,
2123 failrec->start,
2124 EXTENT_LOCKED);
2125 spin_unlock(&io_tree->lock);
2126
2127 if (state && state->start <= failrec->start &&
2128 state->end >= failrec->start + failrec->len - 1) {
2129 num_copies = btrfs_num_copies(fs_info, failrec->logical,
2130 failrec->len);
2131 if (num_copies > 1) {
2132 repair_io_failure(fs_info, ino, start, failrec->len,
2133 failrec->logical, page, pg_offset,
2134 failrec->failed_mirror);
2135 }
2136 }
2137
2138out:
2139 free_io_failure(failure_tree, io_tree, failrec);
2140
2141 return 0;
2142}
2143
2144/*
2145 * Can be called when
2146 * - hold extent lock
2147 * - under ordered extent
2148 * - the inode is freeing
2149 */
2150void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start, u64 end)
2151{
2152 struct extent_io_tree *failure_tree = &inode->io_failure_tree;
2153 struct io_failure_record *failrec;
2154 struct extent_state *state, *next;
2155
2156 if (RB_EMPTY_ROOT(&failure_tree->state))
2157 return;
2158
2159 spin_lock(&failure_tree->lock);
2160 state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
2161 while (state) {
2162 if (state->start > end)
2163 break;
2164
2165 ASSERT(state->end <= end);
2166
2167 next = next_state(state);
2168
2169 failrec = state->failrec;
2170 free_extent_state(state);
2171 kfree(failrec);
2172
2173 state = next;
2174 }
2175 spin_unlock(&failure_tree->lock);
2176}
2177
2178int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
2179 struct io_failure_record **failrec_ret)
2180{
2181 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2182 struct io_failure_record *failrec;
2183 struct extent_map *em;
2184 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2185 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2186 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2187 int ret;
2188 u64 logical;
2189
2190 ret = get_state_failrec(failure_tree, start, &failrec);
2191 if (ret) {
2192 failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
2193 if (!failrec)
2194 return -ENOMEM;
2195
2196 failrec->start = start;
2197 failrec->len = end - start + 1;
2198 failrec->this_mirror = 0;
2199 failrec->bio_flags = 0;
2200 failrec->in_validation = 0;
2201
2202 read_lock(&em_tree->lock);
2203 em = lookup_extent_mapping(em_tree, start, failrec->len);
2204 if (!em) {
2205 read_unlock(&em_tree->lock);
2206 kfree(failrec);
2207 return -EIO;
2208 }
2209
2210 if (em->start > start || em->start + em->len <= start) {
2211 free_extent_map(em);
2212 em = NULL;
2213 }
2214 read_unlock(&em_tree->lock);
2215 if (!em) {
2216 kfree(failrec);
2217 return -EIO;
2218 }
2219
2220 logical = start - em->start;
2221 logical = em->block_start + logical;
2222 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2223 logical = em->block_start;
2224 failrec->bio_flags = EXTENT_BIO_COMPRESSED;
2225 extent_set_compress_type(&failrec->bio_flags,
2226 em->compress_type);
2227 }
2228
2229 btrfs_debug(fs_info,
2230 "Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu",
2231 logical, start, failrec->len);
2232
2233 failrec->logical = logical;
2234 free_extent_map(em);
2235
2236 /* set the bits in the private failure tree */
2237 ret = set_extent_bits(failure_tree, start, end,
2238 EXTENT_LOCKED | EXTENT_DIRTY);
2239 if (ret >= 0)
2240 ret = set_state_failrec(failure_tree, start, failrec);
2241 /* set the bits in the inode's tree */
2242 if (ret >= 0)
2243 ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED);
2244 if (ret < 0) {
2245 kfree(failrec);
2246 return ret;
2247 }
2248 } else {
2249 btrfs_debug(fs_info,
2250 "Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d",
2251 failrec->logical, failrec->start, failrec->len,
2252 failrec->in_validation);
2253 /*
2254 * when data can be on disk more than twice, add to failrec here
2255 * (e.g. with a list for failed_mirror) to make
2256 * clean_io_failure() clean all those errors at once.
2257 */
2258 }
2259
2260 *failrec_ret = failrec;
2261
2262 return 0;
2263}
2264
2265bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages,
2266 struct io_failure_record *failrec, int failed_mirror)
2267{
2268 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2269 int num_copies;
2270
2271 num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
2272 if (num_copies == 1) {
2273 /*
2274 * we only have a single copy of the data, so don't bother with
2275 * all the retry and error correction code that follows. no
2276 * matter what the error is, it is very likely to persist.
2277 */
2278 btrfs_debug(fs_info,
2279 "Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
2280 num_copies, failrec->this_mirror, failed_mirror);
2281 return false;
2282 }
2283
2284 /*
2285 * there are two premises:
2286 * a) deliver good data to the caller
2287 * b) correct the bad sectors on disk
2288 */
2289 if (failed_bio_pages > 1) {
2290 /*
2291 * to fulfill b), we need to know the exact failing sectors, as
2292 * we don't want to rewrite any more than the failed ones. thus,
2293 * we need separate read requests for the failed bio
2294 *
2295 * if the following BUG_ON triggers, our validation request got
2296 * merged. we need separate requests for our algorithm to work.
2297 */
2298 BUG_ON(failrec->in_validation);
2299 failrec->in_validation = 1;
2300 failrec->this_mirror = failed_mirror;
2301 } else {
2302 /*
2303 * we're ready to fulfill a) and b) alongside. get a good copy
2304 * of the failed sector and if we succeed, we have setup
2305 * everything for repair_io_failure to do the rest for us.
2306 */
2307 if (failrec->in_validation) {
2308 BUG_ON(failrec->this_mirror != failed_mirror);
2309 failrec->in_validation = 0;
2310 failrec->this_mirror = 0;
2311 }
2312 failrec->failed_mirror = failed_mirror;
2313 failrec->this_mirror++;
2314 if (failrec->this_mirror == failed_mirror)
2315 failrec->this_mirror++;
2316 }
2317
2318 if (failrec->this_mirror > num_copies) {
2319 btrfs_debug(fs_info,
2320 "Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
2321 num_copies, failrec->this_mirror, failed_mirror);
2322 return false;
2323 }
2324
2325 return true;
2326}
2327
2328
2329struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
2330 struct io_failure_record *failrec,
2331 struct page *page, int pg_offset, int icsum,
2332 bio_end_io_t *endio_func, void *data)
2333{
2334 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2335 struct bio *bio;
2336 struct btrfs_io_bio *btrfs_failed_bio;
2337 struct btrfs_io_bio *btrfs_bio;
2338
2339 bio = btrfs_io_bio_alloc(1);
2340 bio->bi_end_io = endio_func;
2341 bio->bi_iter.bi_sector = failrec->logical >> 9;
2342 bio_set_dev(bio, fs_info->fs_devices->latest_bdev);
2343 bio->bi_iter.bi_size = 0;
2344 bio->bi_private = data;
2345
2346 btrfs_failed_bio = btrfs_io_bio(failed_bio);
2347 if (btrfs_failed_bio->csum) {
2348 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
2349
2350 btrfs_bio = btrfs_io_bio(bio);
2351 btrfs_bio->csum = btrfs_bio->csum_inline;
2352 icsum *= csum_size;
2353 memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
2354 csum_size);
2355 }
2356
2357 bio_add_page(bio, page, failrec->len, pg_offset);
2358
2359 return bio;
2360}
2361
2362/*
2363 * this is a generic handler for readpage errors (default
2364 * readpage_io_failed_hook). if other copies exist, read those and write back
2365 * good data to the failed position. does not investigate in remapping the
2366 * failed extent elsewhere, hoping the device will be smart enough to do this as
2367 * needed
2368 */
2369
2370static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
2371 struct page *page, u64 start, u64 end,
2372 int failed_mirror)
2373{
2374 struct io_failure_record *failrec;
2375 struct inode *inode = page->mapping->host;
2376 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2377 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2378 struct bio *bio;
2379 int read_mode = 0;
2380 blk_status_t status;
2381 int ret;
2382 unsigned failed_bio_pages = bio_pages_all(failed_bio);
2383
2384 BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
2385
2386 ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
2387 if (ret)
2388 return ret;
2389
2390 if (!btrfs_check_repairable(inode, failed_bio_pages, failrec,
2391 failed_mirror)) {
2392 free_io_failure(failure_tree, tree, failrec);
2393 return -EIO;
2394 }
2395
2396 if (failed_bio_pages > 1)
2397 read_mode |= REQ_FAILFAST_DEV;
2398
2399 phy_offset >>= inode->i_sb->s_blocksize_bits;
2400 bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
2401 start - page_offset(page),
2402 (int)phy_offset, failed_bio->bi_end_io,
2403 NULL);
2404 bio_set_op_attrs(bio, REQ_OP_READ, read_mode);
2405
2406 btrfs_debug(btrfs_sb(inode->i_sb),
2407 "Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d",
2408 read_mode, failrec->this_mirror, failrec->in_validation);
2409
2410 status = tree->ops->submit_bio_hook(tree->private_data, bio, failrec->this_mirror,
2411 failrec->bio_flags, 0);
2412 if (status) {
2413 free_io_failure(failure_tree, tree, failrec);
2414 bio_put(bio);
2415 ret = blk_status_to_errno(status);
2416 }
2417
2418 return ret;
2419}
2420
2421/* lots and lots of room for performance fixes in the end_bio funcs */
2422
2423void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
2424{
2425 int uptodate = (err == 0);
2426 struct extent_io_tree *tree;
2427 int ret = 0;
2428
2429 tree = &BTRFS_I(page->mapping->host)->io_tree;
2430
2431 if (tree->ops && tree->ops->writepage_end_io_hook)
2432 tree->ops->writepage_end_io_hook(page, start, end, NULL,
2433 uptodate);
2434
2435 if (!uptodate) {
2436 ClearPageUptodate(page);
2437 SetPageError(page);
2438 ret = err < 0 ? err : -EIO;
2439 mapping_set_error(page->mapping, ret);
2440 }
2441}
2442
2443/*
2444 * after a writepage IO is done, we need to:
2445 * clear the uptodate bits on error
2446 * clear the writeback bits in the extent tree for this IO
2447 * end_page_writeback if the page has no more pending IO
2448 *
2449 * Scheduling is not allowed, so the extent state tree is expected
2450 * to have one and only one object corresponding to this IO.
2451 */
2452static void end_bio_extent_writepage(struct bio *bio)
2453{
2454 int error = blk_status_to_errno(bio->bi_status);
2455 struct bio_vec *bvec;
2456 u64 start;
2457 u64 end;
2458 int i;
2459
2460 ASSERT(!bio_flagged(bio, BIO_CLONED));
2461 bio_for_each_segment_all(bvec, bio, i) {
2462 struct page *page = bvec->bv_page;
2463 struct inode *inode = page->mapping->host;
2464 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2465
2466 /* We always issue full-page reads, but if some block
2467 * in a page fails to read, blk_update_request() will
2468 * advance bv_offset and adjust bv_len to compensate.
2469 * Print a warning for nonzero offsets, and an error
2470 * if they don't add up to a full page. */
2471 if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2472 if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2473 btrfs_err(fs_info,
2474 "partial page write in btrfs with offset %u and length %u",
2475 bvec->bv_offset, bvec->bv_len);
2476 else
2477 btrfs_info(fs_info,
2478 "incomplete page write in btrfs with offset %u and length %u",
2479 bvec->bv_offset, bvec->bv_len);
2480 }
2481
2482 start = page_offset(page);
2483 end = start + bvec->bv_offset + bvec->bv_len - 1;
2484
2485 end_extent_writepage(page, error, start, end);
2486 end_page_writeback(page);
2487 }
2488
2489 bio_put(bio);
2490}
2491
2492static void
2493endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
2494 int uptodate)
2495{
2496 struct extent_state *cached = NULL;
2497 u64 end = start + len - 1;
2498
2499 if (uptodate && tree->track_uptodate)
2500 set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
2501 unlock_extent_cached_atomic(tree, start, end, &cached);
2502}
2503
2504/*
2505 * after a readpage IO is done, we need to:
2506 * clear the uptodate bits on error
2507 * set the uptodate bits if things worked
2508 * set the page up to date if all extents in the tree are uptodate
2509 * clear the lock bit in the extent tree
2510 * unlock the page if there are no other extents locked for it
2511 *
2512 * Scheduling is not allowed, so the extent state tree is expected
2513 * to have one and only one object corresponding to this IO.
2514 */
2515static void end_bio_extent_readpage(struct bio *bio)
2516{
2517 struct bio_vec *bvec;
2518 int uptodate = !bio->bi_status;
2519 struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2520 struct extent_io_tree *tree, *failure_tree;
2521 u64 offset = 0;
2522 u64 start;
2523 u64 end;
2524 u64 len;
2525 u64 extent_start = 0;
2526 u64 extent_len = 0;
2527 int mirror;
2528 int ret;
2529 int i;
2530
2531 ASSERT(!bio_flagged(bio, BIO_CLONED));
2532 bio_for_each_segment_all(bvec, bio, i) {
2533 struct page *page = bvec->bv_page;
2534 struct inode *inode = page->mapping->host;
2535 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2536
2537 btrfs_debug(fs_info,
2538 "end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
2539 (u64)bio->bi_iter.bi_sector, bio->bi_status,
2540 io_bio->mirror_num);
2541 tree = &BTRFS_I(inode)->io_tree;
2542 failure_tree = &BTRFS_I(inode)->io_failure_tree;
2543
2544 /* We always issue full-page reads, but if some block
2545 * in a page fails to read, blk_update_request() will
2546 * advance bv_offset and adjust bv_len to compensate.
2547 * Print a warning for nonzero offsets, and an error
2548 * if they don't add up to a full page. */
2549 if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2550 if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2551 btrfs_err(fs_info,
2552 "partial page read in btrfs with offset %u and length %u",
2553 bvec->bv_offset, bvec->bv_len);
2554 else
2555 btrfs_info(fs_info,
2556 "incomplete page read in btrfs with offset %u and length %u",
2557 bvec->bv_offset, bvec->bv_len);
2558 }
2559
2560 start = page_offset(page);
2561 end = start + bvec->bv_offset + bvec->bv_len - 1;
2562 len = bvec->bv_len;
2563
2564 mirror = io_bio->mirror_num;
2565 if (likely(uptodate && tree->ops)) {
2566 ret = tree->ops->readpage_end_io_hook(io_bio, offset,
2567 page, start, end,
2568 mirror);
2569 if (ret)
2570 uptodate = 0;
2571 else
2572 clean_io_failure(BTRFS_I(inode)->root->fs_info,
2573 failure_tree, tree, start,
2574 page,
2575 btrfs_ino(BTRFS_I(inode)), 0);
2576 }
2577
2578 if (likely(uptodate))
2579 goto readpage_ok;
2580
2581 if (tree->ops) {
2582 ret = tree->ops->readpage_io_failed_hook(page, mirror);
2583 if (ret == -EAGAIN) {
2584 /*
2585 * Data inode's readpage_io_failed_hook() always
2586 * returns -EAGAIN.
2587 *
2588 * The generic bio_readpage_error handles errors
2589 * the following way: If possible, new read
2590 * requests are created and submitted and will
2591 * end up in end_bio_extent_readpage as well (if
2592 * we're lucky, not in the !uptodate case). In
2593 * that case it returns 0 and we just go on with
2594 * the next page in our bio. If it can't handle
2595 * the error it will return -EIO and we remain
2596 * responsible for that page.
2597 */
2598 ret = bio_readpage_error(bio, offset, page,
2599 start, end, mirror);
2600 if (ret == 0) {
2601 uptodate = !bio->bi_status;
2602 offset += len;
2603 continue;
2604 }
2605 }
2606
2607 /*
2608 * metadata's readpage_io_failed_hook() always returns
2609 * -EIO and fixes nothing. -EIO is also returned if
2610 * data inode error could not be fixed.
2611 */
2612 ASSERT(ret == -EIO);
2613 }
2614readpage_ok:
2615 if (likely(uptodate)) {
2616 loff_t i_size = i_size_read(inode);
2617 pgoff_t end_index = i_size >> PAGE_SHIFT;
2618 unsigned off;
2619
2620 /* Zero out the end if this page straddles i_size */
2621 off = i_size & (PAGE_SIZE-1);
2622 if (page->index == end_index && off)
2623 zero_user_segment(page, off, PAGE_SIZE);
2624 SetPageUptodate(page);
2625 } else {
2626 ClearPageUptodate(page);
2627 SetPageError(page);
2628 }
2629 unlock_page(page);
2630 offset += len;
2631
2632 if (unlikely(!uptodate)) {
2633 if (extent_len) {
2634 endio_readpage_release_extent(tree,
2635 extent_start,
2636 extent_len, 1);
2637 extent_start = 0;
2638 extent_len = 0;
2639 }
2640 endio_readpage_release_extent(tree, start,
2641 end - start + 1, 0);
2642 } else if (!extent_len) {
2643 extent_start = start;
2644 extent_len = end + 1 - start;
2645 } else if (extent_start + extent_len == start) {
2646 extent_len += end + 1 - start;
2647 } else {
2648 endio_readpage_release_extent(tree, extent_start,
2649 extent_len, uptodate);
2650 extent_start = start;
2651 extent_len = end + 1 - start;
2652 }
2653 }
2654
2655 if (extent_len)
2656 endio_readpage_release_extent(tree, extent_start, extent_len,
2657 uptodate);
2658 if (io_bio->end_io)
2659 io_bio->end_io(io_bio, blk_status_to_errno(bio->bi_status));
2660 bio_put(bio);
2661}
2662
2663/*
2664 * Initialize the members up to but not including 'bio'. Use after allocating a
2665 * new bio by bio_alloc_bioset as it does not initialize the bytes outside of
2666 * 'bio' because use of __GFP_ZERO is not supported.
2667 */
2668static inline void btrfs_io_bio_init(struct btrfs_io_bio *btrfs_bio)
2669{
2670 memset(btrfs_bio, 0, offsetof(struct btrfs_io_bio, bio));
2671}
2672
2673/*
2674 * The following helpers allocate a bio. As it's backed by a bioset, it'll
2675 * never fail. We're returning a bio right now but you can call btrfs_io_bio
2676 * for the appropriate container_of magic
2677 */
2678struct bio *btrfs_bio_alloc(struct block_device *bdev, u64 first_byte)
2679{
2680 struct bio *bio;
2681
2682 bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, btrfs_bioset);
2683 bio_set_dev(bio, bdev);
2684 bio->bi_iter.bi_sector = first_byte >> 9;
2685 btrfs_io_bio_init(btrfs_io_bio(bio));
2686 return bio;
2687}
2688
2689struct bio *btrfs_bio_clone(struct bio *bio)
2690{
2691 struct btrfs_io_bio *btrfs_bio;
2692 struct bio *new;
2693
2694 /* Bio allocation backed by a bioset does not fail */
2695 new = bio_clone_fast(bio, GFP_NOFS, btrfs_bioset);
2696 btrfs_bio = btrfs_io_bio(new);
2697 btrfs_io_bio_init(btrfs_bio);
2698 btrfs_bio->iter = bio->bi_iter;
2699 return new;
2700}
2701
2702struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs)
2703{
2704 struct bio *bio;
2705
2706 /* Bio allocation backed by a bioset does not fail */
2707 bio = bio_alloc_bioset(GFP_NOFS, nr_iovecs, btrfs_bioset);
2708 btrfs_io_bio_init(btrfs_io_bio(bio));
2709 return bio;
2710}
2711
2712struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size)
2713{
2714 struct bio *bio;
2715 struct btrfs_io_bio *btrfs_bio;
2716
2717 /* this will never fail when it's backed by a bioset */
2718 bio = bio_clone_fast(orig, GFP_NOFS, btrfs_bioset);
2719 ASSERT(bio);
2720
2721 btrfs_bio = btrfs_io_bio(bio);
2722 btrfs_io_bio_init(btrfs_bio);
2723
2724 bio_trim(bio, offset >> 9, size >> 9);
2725 btrfs_bio->iter = bio->bi_iter;
2726 return bio;
2727}
2728
2729static int __must_check submit_one_bio(struct bio *bio, int mirror_num,
2730 unsigned long bio_flags)
2731{
2732 blk_status_t ret = 0;
2733 struct bio_vec *bvec = bio_last_bvec_all(bio);
2734 struct page *page = bvec->bv_page;
2735 struct extent_io_tree *tree = bio->bi_private;
2736 u64 start;
2737
2738 start = page_offset(page) + bvec->bv_offset;
2739
2740 bio->bi_private = NULL;
2741
2742 if (tree->ops)
2743 ret = tree->ops->submit_bio_hook(tree->private_data, bio,
2744 mirror_num, bio_flags, start);
2745 else
2746 btrfsic_submit_bio(bio);
2747
2748 return blk_status_to_errno(ret);
2749}
2750
2751/*
2752 * @opf: bio REQ_OP_* and REQ_* flags as one value
2753 * @tree: tree so we can call our merge_bio hook
2754 * @wbc: optional writeback control for io accounting
2755 * @page: page to add to the bio
2756 * @pg_offset: offset of the new bio or to check whether we are adding
2757 * a contiguous page to the previous one
2758 * @size: portion of page that we want to write
2759 * @offset: starting offset in the page
2760 * @bdev: attach newly created bios to this bdev
2761 * @bio_ret: must be valid pointer, newly allocated bio will be stored there
2762 * @end_io_func: end_io callback for new bio
2763 * @mirror_num: desired mirror to read/write
2764 * @prev_bio_flags: flags of previous bio to see if we can merge the current one
2765 * @bio_flags: flags of the current bio to see if we can merge them
2766 */
2767static int submit_extent_page(unsigned int opf, struct extent_io_tree *tree,
2768 struct writeback_control *wbc,
2769 struct page *page, u64 offset,
2770 size_t size, unsigned long pg_offset,
2771 struct block_device *bdev,
2772 struct bio **bio_ret,
2773 bio_end_io_t end_io_func,
2774 int mirror_num,
2775 unsigned long prev_bio_flags,
2776 unsigned long bio_flags,
2777 bool force_bio_submit)
2778{
2779 int ret = 0;
2780 struct bio *bio;
2781 size_t page_size = min_t(size_t, size, PAGE_SIZE);
2782 sector_t sector = offset >> 9;
2783
2784 ASSERT(bio_ret);
2785
2786 if (*bio_ret) {
2787 bool contig;
2788 bool can_merge = true;
2789
2790 bio = *bio_ret;
2791 if (prev_bio_flags & EXTENT_BIO_COMPRESSED)
2792 contig = bio->bi_iter.bi_sector == sector;
2793 else
2794 contig = bio_end_sector(bio) == sector;
2795
2796 if (tree->ops && tree->ops->merge_bio_hook(page, offset,
2797 page_size, bio, bio_flags))
2798 can_merge = false;
2799
2800 if (prev_bio_flags != bio_flags || !contig || !can_merge ||
2801 force_bio_submit ||
2802 bio_add_page(bio, page, page_size, pg_offset) < page_size) {
2803 ret = submit_one_bio(bio, mirror_num, prev_bio_flags);
2804 if (ret < 0) {
2805 *bio_ret = NULL;
2806 return ret;
2807 }
2808 bio = NULL;
2809 } else {
2810 if (wbc)
2811 wbc_account_io(wbc, page, page_size);
2812 return 0;
2813 }
2814 }
2815
2816 bio = btrfs_bio_alloc(bdev, offset);
2817 bio_add_page(bio, page, page_size, pg_offset);
2818 bio->bi_end_io = end_io_func;
2819 bio->bi_private = tree;
2820 bio->bi_write_hint = page->mapping->host->i_write_hint;
2821 bio->bi_opf = opf;
2822 if (wbc) {
2823 wbc_init_bio(wbc, bio);
2824 wbc_account_io(wbc, page, page_size);
2825 }
2826
2827 *bio_ret = bio;
2828
2829 return ret;
2830}
2831
2832static void attach_extent_buffer_page(struct extent_buffer *eb,
2833 struct page *page)
2834{
2835 if (!PagePrivate(page)) {
2836 SetPagePrivate(page);
2837 get_page(page);
2838 set_page_private(page, (unsigned long)eb);
2839 } else {
2840 WARN_ON(page->private != (unsigned long)eb);
2841 }
2842}
2843
2844void set_page_extent_mapped(struct page *page)
2845{
2846 if (!PagePrivate(page)) {
2847 SetPagePrivate(page);
2848 get_page(page);
2849 set_page_private(page, EXTENT_PAGE_PRIVATE);
2850 }
2851}
2852
2853static struct extent_map *
2854__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
2855 u64 start, u64 len, get_extent_t *get_extent,
2856 struct extent_map **em_cached)
2857{
2858 struct extent_map *em;
2859
2860 if (em_cached && *em_cached) {
2861 em = *em_cached;
2862 if (extent_map_in_tree(em) && start >= em->start &&
2863 start < extent_map_end(em)) {
2864 refcount_inc(&em->refs);
2865 return em;
2866 }
2867
2868 free_extent_map(em);
2869 *em_cached = NULL;
2870 }
2871
2872 em = get_extent(BTRFS_I(inode), page, pg_offset, start, len, 0);
2873 if (em_cached && !IS_ERR_OR_NULL(em)) {
2874 BUG_ON(*em_cached);
2875 refcount_inc(&em->refs);
2876 *em_cached = em;
2877 }
2878 return em;
2879}
2880/*
2881 * basic readpage implementation. Locked extent state structs are inserted
2882 * into the tree that are removed when the IO is done (by the end_io
2883 * handlers)
2884 * XXX JDM: This needs looking at to ensure proper page locking
2885 * return 0 on success, otherwise return error
2886 */
2887static int __do_readpage(struct extent_io_tree *tree,
2888 struct page *page,
2889 get_extent_t *get_extent,
2890 struct extent_map **em_cached,
2891 struct bio **bio, int mirror_num,
2892 unsigned long *bio_flags, unsigned int read_flags,
2893 u64 *prev_em_start)
2894{
2895 struct inode *inode = page->mapping->host;
2896 u64 start = page_offset(page);
2897 const u64 end = start + PAGE_SIZE - 1;
2898 u64 cur = start;
2899 u64 extent_offset;
2900 u64 last_byte = i_size_read(inode);
2901 u64 block_start;
2902 u64 cur_end;
2903 struct extent_map *em;
2904 struct block_device *bdev;
2905 int ret = 0;
2906 int nr = 0;
2907 size_t pg_offset = 0;
2908 size_t iosize;
2909 size_t disk_io_size;
2910 size_t blocksize = inode->i_sb->s_blocksize;
2911 unsigned long this_bio_flag = 0;
2912
2913 set_page_extent_mapped(page);
2914
2915 if (!PageUptodate(page)) {
2916 if (cleancache_get_page(page) == 0) {
2917 BUG_ON(blocksize != PAGE_SIZE);
2918 unlock_extent(tree, start, end);
2919 goto out;
2920 }
2921 }
2922
2923 if (page->index == last_byte >> PAGE_SHIFT) {
2924 char *userpage;
2925 size_t zero_offset = last_byte & (PAGE_SIZE - 1);
2926
2927 if (zero_offset) {
2928 iosize = PAGE_SIZE - zero_offset;
2929 userpage = kmap_atomic(page);
2930 memset(userpage + zero_offset, 0, iosize);
2931 flush_dcache_page(page);
2932 kunmap_atomic(userpage);
2933 }
2934 }
2935 while (cur <= end) {
2936 bool force_bio_submit = false;
2937 u64 offset;
2938
2939 if (cur >= last_byte) {
2940 char *userpage;
2941 struct extent_state *cached = NULL;
2942
2943 iosize = PAGE_SIZE - pg_offset;
2944 userpage = kmap_atomic(page);
2945 memset(userpage + pg_offset, 0, iosize);
2946 flush_dcache_page(page);
2947 kunmap_atomic(userpage);
2948 set_extent_uptodate(tree, cur, cur + iosize - 1,
2949 &cached, GFP_NOFS);
2950 unlock_extent_cached(tree, cur,
2951 cur + iosize - 1, &cached);
2952 break;
2953 }
2954 em = __get_extent_map(inode, page, pg_offset, cur,
2955 end - cur + 1, get_extent, em_cached);
2956 if (IS_ERR_OR_NULL(em)) {
2957 SetPageError(page);
2958 unlock_extent(tree, cur, end);
2959 break;
2960 }
2961 extent_offset = cur - em->start;
2962 BUG_ON(extent_map_end(em) <= cur);
2963 BUG_ON(end < cur);
2964
2965 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2966 this_bio_flag |= EXTENT_BIO_COMPRESSED;
2967 extent_set_compress_type(&this_bio_flag,
2968 em->compress_type);
2969 }
2970
2971 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2972 cur_end = min(extent_map_end(em) - 1, end);
2973 iosize = ALIGN(iosize, blocksize);
2974 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
2975 disk_io_size = em->block_len;
2976 offset = em->block_start;
2977 } else {
2978 offset = em->block_start + extent_offset;
2979 disk_io_size = iosize;
2980 }
2981 bdev = em->bdev;
2982 block_start = em->block_start;
2983 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2984 block_start = EXTENT_MAP_HOLE;
2985
2986 /*
2987 * If we have a file range that points to a compressed extent
2988 * and it's followed by a consecutive file range that points to
2989 * to the same compressed extent (possibly with a different
2990 * offset and/or length, so it either points to the whole extent
2991 * or only part of it), we must make sure we do not submit a
2992 * single bio to populate the pages for the 2 ranges because
2993 * this makes the compressed extent read zero out the pages
2994 * belonging to the 2nd range. Imagine the following scenario:
2995 *
2996 * File layout
2997 * [0 - 8K] [8K - 24K]
2998 * | |
2999 * | |
3000 * points to extent X, points to extent X,
3001 * offset 4K, length of 8K offset 0, length 16K
3002 *
3003 * [extent X, compressed length = 4K uncompressed length = 16K]
3004 *
3005 * If the bio to read the compressed extent covers both ranges,
3006 * it will decompress extent X into the pages belonging to the
3007 * first range and then it will stop, zeroing out the remaining
3008 * pages that belong to the other range that points to extent X.
3009 * So here we make sure we submit 2 bios, one for the first
3010 * range and another one for the third range. Both will target
3011 * the same physical extent from disk, but we can't currently
3012 * make the compressed bio endio callback populate the pages
3013 * for both ranges because each compressed bio is tightly
3014 * coupled with a single extent map, and each range can have
3015 * an extent map with a different offset value relative to the
3016 * uncompressed data of our extent and different lengths. This
3017 * is a corner case so we prioritize correctness over
3018 * non-optimal behavior (submitting 2 bios for the same extent).
3019 */
3020 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
3021 prev_em_start && *prev_em_start != (u64)-1 &&
3022 *prev_em_start != em->orig_start)
3023 force_bio_submit = true;
3024
3025 if (prev_em_start)
3026 *prev_em_start = em->orig_start;
3027
3028 free_extent_map(em);
3029 em = NULL;
3030
3031 /* we've found a hole, just zero and go on */
3032 if (block_start == EXTENT_MAP_HOLE) {
3033 char *userpage;
3034 struct extent_state *cached = NULL;
3035
3036 userpage = kmap_atomic(page);
3037 memset(userpage + pg_offset, 0, iosize);
3038 flush_dcache_page(page);
3039 kunmap_atomic(userpage);
3040
3041 set_extent_uptodate(tree, cur, cur + iosize - 1,
3042 &cached, GFP_NOFS);
3043 unlock_extent_cached(tree, cur,
3044 cur + iosize - 1, &cached);
3045 cur = cur + iosize;
3046 pg_offset += iosize;
3047 continue;
3048 }
3049 /* the get_extent function already copied into the page */
3050 if (test_range_bit(tree, cur, cur_end,
3051 EXTENT_UPTODATE, 1, NULL)) {
3052 check_page_uptodate(tree, page);
3053 unlock_extent(tree, cur, cur + iosize - 1);
3054 cur = cur + iosize;
3055 pg_offset += iosize;
3056 continue;
3057 }
3058 /* we have an inline extent but it didn't get marked up
3059 * to date. Error out
3060 */
3061 if (block_start == EXTENT_MAP_INLINE) {
3062 SetPageError(page);
3063 unlock_extent(tree, cur, cur + iosize - 1);
3064 cur = cur + iosize;
3065 pg_offset += iosize;
3066 continue;
3067 }
3068
3069 ret = submit_extent_page(REQ_OP_READ | read_flags, tree, NULL,
3070 page, offset, disk_io_size,
3071 pg_offset, bdev, bio,
3072 end_bio_extent_readpage, mirror_num,
3073 *bio_flags,
3074 this_bio_flag,
3075 force_bio_submit);
3076 if (!ret) {
3077 nr++;
3078 *bio_flags = this_bio_flag;
3079 } else {
3080 SetPageError(page);
3081 unlock_extent(tree, cur, cur + iosize - 1);
3082 goto out;
3083 }
3084 cur = cur + iosize;
3085 pg_offset += iosize;
3086 }
3087out:
3088 if (!nr) {
3089 if (!PageError(page))
3090 SetPageUptodate(page);
3091 unlock_page(page);
3092 }
3093 return ret;
3094}
3095
3096static inline void __do_contiguous_readpages(struct extent_io_tree *tree,
3097 struct page *pages[], int nr_pages,
3098 u64 start, u64 end,
3099 struct extent_map **em_cached,
3100 struct bio **bio,
3101 unsigned long *bio_flags,
3102 u64 *prev_em_start)
3103{
3104 struct inode *inode;
3105 struct btrfs_ordered_extent *ordered;
3106 int index;
3107
3108 inode = pages[0]->mapping->host;
3109 while (1) {
3110 lock_extent(tree, start, end);
3111 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
3112 end - start + 1);
3113 if (!ordered)
3114 break;
3115 unlock_extent(tree, start, end);
3116 btrfs_start_ordered_extent(inode, ordered, 1);
3117 btrfs_put_ordered_extent(ordered);
3118 }
3119
3120 for (index = 0; index < nr_pages; index++) {
3121 __do_readpage(tree, pages[index], btrfs_get_extent, em_cached,
3122 bio, 0, bio_flags, 0, prev_em_start);
3123 put_page(pages[index]);
3124 }
3125}
3126
3127static void __extent_readpages(struct extent_io_tree *tree,
3128 struct page *pages[],
3129 int nr_pages,
3130 struct extent_map **em_cached,
3131 struct bio **bio, unsigned long *bio_flags,
3132 u64 *prev_em_start)
3133{
3134 u64 start = 0;
3135 u64 end = 0;
3136 u64 page_start;
3137 int index;
3138 int first_index = 0;
3139
3140 for (index = 0; index < nr_pages; index++) {
3141 page_start = page_offset(pages[index]);
3142 if (!end) {
3143 start = page_start;
3144 end = start + PAGE_SIZE - 1;
3145 first_index = index;
3146 } else if (end + 1 == page_start) {
3147 end += PAGE_SIZE;
3148 } else {
3149 __do_contiguous_readpages(tree, &pages[first_index],
3150 index - first_index, start,
3151 end, em_cached,
3152 bio, bio_flags,
3153 prev_em_start);
3154 start = page_start;
3155 end = start + PAGE_SIZE - 1;
3156 first_index = index;
3157 }
3158 }
3159
3160 if (end)
3161 __do_contiguous_readpages(tree, &pages[first_index],
3162 index - first_index, start,
3163 end, em_cached, bio,
3164 bio_flags, prev_em_start);
3165}
3166
3167static int __extent_read_full_page(struct extent_io_tree *tree,
3168 struct page *page,
3169 get_extent_t *get_extent,
3170 struct bio **bio, int mirror_num,
3171 unsigned long *bio_flags,
3172 unsigned int read_flags)
3173{
3174 struct inode *inode = page->mapping->host;
3175 struct btrfs_ordered_extent *ordered;
3176 u64 start = page_offset(page);
3177 u64 end = start + PAGE_SIZE - 1;
3178 int ret;
3179
3180 while (1) {
3181 lock_extent(tree, start, end);
3182 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
3183 PAGE_SIZE);
3184 if (!ordered)
3185 break;
3186 unlock_extent(tree, start, end);
3187 btrfs_start_ordered_extent(inode, ordered, 1);
3188 btrfs_put_ordered_extent(ordered);
3189 }
3190
3191 ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
3192 bio_flags, read_flags, NULL);
3193 return ret;
3194}
3195
3196int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3197 get_extent_t *get_extent, int mirror_num)
3198{
3199 struct bio *bio = NULL;
3200 unsigned long bio_flags = 0;
3201 int ret;
3202
3203 ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3204 &bio_flags, 0);
3205 if (bio)
3206 ret = submit_one_bio(bio, mirror_num, bio_flags);
3207 return ret;
3208}
3209
3210static void update_nr_written(struct writeback_control *wbc,
3211 unsigned long nr_written)
3212{
3213 wbc->nr_to_write -= nr_written;
3214}
3215
3216/*
3217 * helper for __extent_writepage, doing all of the delayed allocation setup.
3218 *
3219 * This returns 1 if our fill_delalloc function did all the work required
3220 * to write the page (copy into inline extent). In this case the IO has
3221 * been started and the page is already unlocked.
3222 *
3223 * This returns 0 if all went well (page still locked)
3224 * This returns < 0 if there were errors (page still locked)
3225 */
3226static noinline_for_stack int writepage_delalloc(struct inode *inode,
3227 struct page *page, struct writeback_control *wbc,
3228 struct extent_page_data *epd,
3229 u64 delalloc_start,
3230 unsigned long *nr_written)
3231{
3232 struct extent_io_tree *tree = epd->tree;
3233 u64 page_end = delalloc_start + PAGE_SIZE - 1;
3234 u64 nr_delalloc;
3235 u64 delalloc_to_write = 0;
3236 u64 delalloc_end = 0;
3237 int ret;
3238 int page_started = 0;
3239
3240 if (epd->extent_locked || !tree->ops || !tree->ops->fill_delalloc)
3241 return 0;
3242
3243 while (delalloc_end < page_end) {
3244 nr_delalloc = find_lock_delalloc_range(inode, tree,
3245 page,
3246 &delalloc_start,
3247 &delalloc_end,
3248 BTRFS_MAX_EXTENT_SIZE);
3249 if (nr_delalloc == 0) {
3250 delalloc_start = delalloc_end + 1;
3251 continue;
3252 }
3253 ret = tree->ops->fill_delalloc(inode, page,
3254 delalloc_start,
3255 delalloc_end,
3256 &page_started,
3257 nr_written, wbc);
3258 /* File system has been set read-only */
3259 if (ret) {
3260 SetPageError(page);
3261 /* fill_delalloc should be return < 0 for error
3262 * but just in case, we use > 0 here meaning the
3263 * IO is started, so we don't want to return > 0
3264 * unless things are going well.
3265 */
3266 ret = ret < 0 ? ret : -EIO;
3267 goto done;
3268 }
3269 /*
3270 * delalloc_end is already one less than the total length, so
3271 * we don't subtract one from PAGE_SIZE
3272 */
3273 delalloc_to_write += (delalloc_end - delalloc_start +
3274 PAGE_SIZE) >> PAGE_SHIFT;
3275 delalloc_start = delalloc_end + 1;
3276 }
3277 if (wbc->nr_to_write < delalloc_to_write) {
3278 int thresh = 8192;
3279
3280 if (delalloc_to_write < thresh * 2)
3281 thresh = delalloc_to_write;
3282 wbc->nr_to_write = min_t(u64, delalloc_to_write,
3283 thresh);
3284 }
3285
3286 /* did the fill delalloc function already unlock and start
3287 * the IO?
3288 */
3289 if (page_started) {
3290 /*
3291 * we've unlocked the page, so we can't update
3292 * the mapping's writeback index, just update
3293 * nr_to_write.
3294 */
3295 wbc->nr_to_write -= *nr_written;
3296 return 1;
3297 }
3298
3299 ret = 0;
3300
3301done:
3302 return ret;
3303}
3304
3305/*
3306 * helper for __extent_writepage. This calls the writepage start hooks,
3307 * and does the loop to map the page into extents and bios.
3308 *
3309 * We return 1 if the IO is started and the page is unlocked,
3310 * 0 if all went well (page still locked)
3311 * < 0 if there were errors (page still locked)
3312 */
3313static noinline_for_stack int __extent_writepage_io(struct inode *inode,
3314 struct page *page,
3315 struct writeback_control *wbc,
3316 struct extent_page_data *epd,
3317 loff_t i_size,
3318 unsigned long nr_written,
3319 unsigned int write_flags, int *nr_ret)
3320{
3321 struct extent_io_tree *tree = epd->tree;
3322 u64 start = page_offset(page);
3323 u64 page_end = start + PAGE_SIZE - 1;
3324 u64 end;
3325 u64 cur = start;
3326 u64 extent_offset;
3327 u64 block_start;
3328 u64 iosize;
3329 struct extent_map *em;
3330 struct block_device *bdev;
3331 size_t pg_offset = 0;
3332 size_t blocksize;
3333 int ret = 0;
3334 int nr = 0;
3335 bool compressed;
3336
3337 if (tree->ops && tree->ops->writepage_start_hook) {
3338 ret = tree->ops->writepage_start_hook(page, start,
3339 page_end);
3340 if (ret) {
3341 /* Fixup worker will requeue */
3342 if (ret == -EBUSY)
3343 wbc->pages_skipped++;
3344 else
3345 redirty_page_for_writepage(wbc, page);
3346
3347 update_nr_written(wbc, nr_written);
3348 unlock_page(page);
3349 return 1;
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(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 u64 offset;
3372
3373 if (cur >= i_size) {
3374 if (tree->ops && tree->ops->writepage_end_io_hook)
3375 tree->ops->writepage_end_io_hook(page, cur,
3376 page_end, NULL, 1);
3377 break;
3378 }
3379 em = btrfs_get_extent(BTRFS_I(inode), page, pg_offset, cur,
3380 end - cur + 1, 1);
3381 if (IS_ERR_OR_NULL(em)) {
3382 SetPageError(page);
3383 ret = PTR_ERR_OR_ZERO(em);
3384 break;
3385 }
3386
3387 extent_offset = cur - em->start;
3388 em_end = extent_map_end(em);
3389 BUG_ON(em_end <= cur);
3390 BUG_ON(end < cur);
3391 iosize = min(em_end - cur, end - cur + 1);
3392 iosize = ALIGN(iosize, blocksize);
3393 offset = em->block_start + extent_offset;
3394 bdev = em->bdev;
3395 block_start = em->block_start;
3396 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3397 free_extent_map(em);
3398 em = NULL;
3399
3400 /*
3401 * compressed and inline extents are written through other
3402 * paths in the FS
3403 */
3404 if (compressed || block_start == EXTENT_MAP_HOLE ||
3405 block_start == EXTENT_MAP_INLINE) {
3406 /*
3407 * end_io notification does not happen here for
3408 * compressed extents
3409 */
3410 if (!compressed && tree->ops &&
3411 tree->ops->writepage_end_io_hook)
3412 tree->ops->writepage_end_io_hook(page, cur,
3413 cur + iosize - 1,
3414 NULL, 1);
3415 else if (compressed) {
3416 /* we don't want to end_page_writeback on
3417 * a compressed extent. this happens
3418 * elsewhere
3419 */
3420 nr++;
3421 }
3422
3423 cur += iosize;
3424 pg_offset += iosize;
3425 continue;
3426 }
3427
3428 set_range_writeback(tree, cur, cur + iosize - 1);
3429 if (!PageWriteback(page)) {
3430 btrfs_err(BTRFS_I(inode)->root->fs_info,
3431 "page %lu not writeback, cur %llu end %llu",
3432 page->index, cur, end);
3433 }
3434
3435 ret = submit_extent_page(REQ_OP_WRITE | write_flags, tree, wbc,
3436 page, offset, iosize, pg_offset,
3437 bdev, &epd->bio,
3438 end_bio_extent_writepage,
3439 0, 0, 0, false);
3440 if (ret) {
3441 SetPageError(page);
3442 if (PageWriteback(page))
3443 end_page_writeback(page);
3444 }
3445
3446 cur = cur + iosize;
3447 pg_offset += iosize;
3448 nr++;
3449 }
3450done:
3451 *nr_ret = nr;
3452 return ret;
3453}
3454
3455/*
3456 * the writepage semantics are similar to regular writepage. extent
3457 * records are inserted to lock ranges in the tree, and as dirty areas
3458 * are found, they are marked writeback. Then the lock bits are removed
3459 * and the end_io handler clears the writeback ranges
3460 */
3461static int __extent_writepage(struct page *page, struct writeback_control *wbc,
3462 struct extent_page_data *epd)
3463{
3464 struct inode *inode = page->mapping->host;
3465 u64 start = page_offset(page);
3466 u64 page_end = start + PAGE_SIZE - 1;
3467 int ret;
3468 int nr = 0;
3469 size_t pg_offset = 0;
3470 loff_t i_size = i_size_read(inode);
3471 unsigned long end_index = i_size >> PAGE_SHIFT;
3472 unsigned int write_flags = 0;
3473 unsigned long nr_written = 0;
3474
3475 write_flags = wbc_to_write_flags(wbc);
3476
3477 trace___extent_writepage(page, inode, wbc);
3478
3479 WARN_ON(!PageLocked(page));
3480
3481 ClearPageError(page);
3482
3483 pg_offset = i_size & (PAGE_SIZE - 1);
3484 if (page->index > end_index ||
3485 (page->index == end_index && !pg_offset)) {
3486 page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
3487 unlock_page(page);
3488 return 0;
3489 }
3490
3491 if (page->index == end_index) {
3492 char *userpage;
3493
3494 userpage = kmap_atomic(page);
3495 memset(userpage + pg_offset, 0,
3496 PAGE_SIZE - pg_offset);
3497 kunmap_atomic(userpage);
3498 flush_dcache_page(page);
3499 }
3500
3501 pg_offset = 0;
3502
3503 set_page_extent_mapped(page);
3504
3505 ret = writepage_delalloc(inode, page, wbc, epd, start, &nr_written);
3506 if (ret == 1)
3507 goto done_unlocked;
3508 if (ret)
3509 goto done;
3510
3511 ret = __extent_writepage_io(inode, page, wbc, epd,
3512 i_size, nr_written, write_flags, &nr);
3513 if (ret == 1)
3514 goto done_unlocked;
3515
3516done:
3517 if (nr == 0) {
3518 /* make sure the mapping tag for page dirty gets cleared */
3519 set_page_writeback(page);
3520 end_page_writeback(page);
3521 }
3522 if (PageError(page)) {
3523 ret = ret < 0 ? ret : -EIO;
3524 end_extent_writepage(page, ret, start, page_end);
3525 }
3526 unlock_page(page);
3527 return ret;
3528
3529done_unlocked:
3530 return 0;
3531}
3532
3533void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3534{
3535 wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
3536 TASK_UNINTERRUPTIBLE);
3537}
3538
3539static noinline_for_stack int
3540lock_extent_buffer_for_io(struct extent_buffer *eb,
3541 struct btrfs_fs_info *fs_info,
3542 struct extent_page_data *epd)
3543{
3544 unsigned long i, num_pages;
3545 int flush = 0;
3546 int ret = 0;
3547
3548 if (!btrfs_try_tree_write_lock(eb)) {
3549 flush = 1;
3550 flush_write_bio(epd);
3551 btrfs_tree_lock(eb);
3552 }
3553
3554 if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
3555 btrfs_tree_unlock(eb);
3556 if (!epd->sync_io)
3557 return 0;
3558 if (!flush) {
3559 flush_write_bio(epd);
3560 flush = 1;
3561 }
3562 while (1) {
3563 wait_on_extent_buffer_writeback(eb);
3564 btrfs_tree_lock(eb);
3565 if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
3566 break;
3567 btrfs_tree_unlock(eb);
3568 }
3569 }
3570
3571 /*
3572 * We need to do this to prevent races in people who check if the eb is
3573 * under IO since we can end up having no IO bits set for a short period
3574 * of time.
3575 */
3576 spin_lock(&eb->refs_lock);
3577 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3578 set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3579 spin_unlock(&eb->refs_lock);
3580 btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3581 percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
3582 -eb->len,
3583 fs_info->dirty_metadata_batch);
3584 ret = 1;
3585 } else {
3586 spin_unlock(&eb->refs_lock);
3587 }
3588
3589 btrfs_tree_unlock(eb);
3590
3591 if (!ret)
3592 return ret;
3593
3594 num_pages = num_extent_pages(eb->start, eb->len);
3595 for (i = 0; i < num_pages; i++) {
3596 struct page *p = eb->pages[i];
3597
3598 if (!trylock_page(p)) {
3599 if (!flush) {
3600 flush_write_bio(epd);
3601 flush = 1;
3602 }
3603 lock_page(p);
3604 }
3605 }
3606
3607 return ret;
3608}
3609
3610static void end_extent_buffer_writeback(struct extent_buffer *eb)
3611{
3612 clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3613 smp_mb__after_atomic();
3614 wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
3615}
3616
3617static void set_btree_ioerr(struct page *page)
3618{
3619 struct extent_buffer *eb = (struct extent_buffer *)page->private;
3620
3621 SetPageError(page);
3622 if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
3623 return;
3624
3625 /*
3626 * If writeback for a btree extent that doesn't belong to a log tree
3627 * failed, increment the counter transaction->eb_write_errors.
3628 * We do this because while the transaction is running and before it's
3629 * committing (when we call filemap_fdata[write|wait]_range against
3630 * the btree inode), we might have
3631 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
3632 * returns an error or an error happens during writeback, when we're
3633 * committing the transaction we wouldn't know about it, since the pages
3634 * can be no longer dirty nor marked anymore for writeback (if a
3635 * subsequent modification to the extent buffer didn't happen before the
3636 * transaction commit), which makes filemap_fdata[write|wait]_range not
3637 * able to find the pages tagged with SetPageError at transaction
3638 * commit time. So if this happens we must abort the transaction,
3639 * otherwise we commit a super block with btree roots that point to
3640 * btree nodes/leafs whose content on disk is invalid - either garbage
3641 * or the content of some node/leaf from a past generation that got
3642 * cowed or deleted and is no longer valid.
3643 *
3644 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
3645 * not be enough - we need to distinguish between log tree extents vs
3646 * non-log tree extents, and the next filemap_fdatawait_range() call
3647 * will catch and clear such errors in the mapping - and that call might
3648 * be from a log sync and not from a transaction commit. Also, checking
3649 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
3650 * not done and would not be reliable - the eb might have been released
3651 * from memory and reading it back again means that flag would not be
3652 * set (since it's a runtime flag, not persisted on disk).
3653 *
3654 * Using the flags below in the btree inode also makes us achieve the
3655 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
3656 * writeback for all dirty pages and before filemap_fdatawait_range()
3657 * is called, the writeback for all dirty pages had already finished
3658 * with errors - because we were not using AS_EIO/AS_ENOSPC,
3659 * filemap_fdatawait_range() would return success, as it could not know
3660 * that writeback errors happened (the pages were no longer tagged for
3661 * writeback).
3662 */
3663 switch (eb->log_index) {
3664 case -1:
3665 set_bit(BTRFS_FS_BTREE_ERR, &eb->fs_info->flags);
3666 break;
3667 case 0:
3668 set_bit(BTRFS_FS_LOG1_ERR, &eb->fs_info->flags);
3669 break;
3670 case 1:
3671 set_bit(BTRFS_FS_LOG2_ERR, &eb->fs_info->flags);
3672 break;
3673 default:
3674 BUG(); /* unexpected, logic error */
3675 }
3676}
3677
3678static void end_bio_extent_buffer_writepage(struct bio *bio)
3679{
3680 struct bio_vec *bvec;
3681 struct extent_buffer *eb;
3682 int i, done;
3683
3684 ASSERT(!bio_flagged(bio, BIO_CLONED));
3685 bio_for_each_segment_all(bvec, bio, i) {
3686 struct page *page = bvec->bv_page;
3687
3688 eb = (struct extent_buffer *)page->private;
3689 BUG_ON(!eb);
3690 done = atomic_dec_and_test(&eb->io_pages);
3691
3692 if (bio->bi_status ||
3693 test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
3694 ClearPageUptodate(page);
3695 set_btree_ioerr(page);
3696 }
3697
3698 end_page_writeback(page);
3699
3700 if (!done)
3701 continue;
3702
3703 end_extent_buffer_writeback(eb);
3704 }
3705
3706 bio_put(bio);
3707}
3708
3709static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3710 struct btrfs_fs_info *fs_info,
3711 struct writeback_control *wbc,
3712 struct extent_page_data *epd)
3713{
3714 struct block_device *bdev = fs_info->fs_devices->latest_bdev;
3715 struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3716 u64 offset = eb->start;
3717 u32 nritems;
3718 unsigned long i, num_pages;
3719 unsigned long start, end;
3720 unsigned int write_flags = wbc_to_write_flags(wbc) | REQ_META;
3721 int ret = 0;
3722
3723 clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
3724 num_pages = num_extent_pages(eb->start, eb->len);
3725 atomic_set(&eb->io_pages, num_pages);
3726
3727 /* set btree blocks beyond nritems with 0 to avoid stale content. */
3728 nritems = btrfs_header_nritems(eb);
3729 if (btrfs_header_level(eb) > 0) {
3730 end = btrfs_node_key_ptr_offset(nritems);
3731
3732 memzero_extent_buffer(eb, end, eb->len - end);
3733 } else {
3734 /*
3735 * leaf:
3736 * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
3737 */
3738 start = btrfs_item_nr_offset(nritems);
3739 end = BTRFS_LEAF_DATA_OFFSET + leaf_data_end(fs_info, eb);
3740 memzero_extent_buffer(eb, start, end - start);
3741 }
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(REQ_OP_WRITE | write_flags, tree, wbc,
3749 p, offset, PAGE_SIZE, 0, bdev,
3750 &epd->bio,
3751 end_bio_extent_buffer_writepage,
3752 0, 0, 0, false);
3753 if (ret) {
3754 set_btree_ioerr(p);
3755 if (PageWriteback(p))
3756 end_page_writeback(p);
3757 if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
3758 end_extent_buffer_writeback(eb);
3759 ret = -EIO;
3760 break;
3761 }
3762 offset += PAGE_SIZE;
3763 update_nr_written(wbc, 1);
3764 unlock_page(p);
3765 }
3766
3767 if (unlikely(ret)) {
3768 for (; i < num_pages; i++) {
3769 struct page *p = eb->pages[i];
3770 clear_page_dirty_for_io(p);
3771 unlock_page(p);
3772 }
3773 }
3774
3775 return ret;
3776}
3777
3778int btree_write_cache_pages(struct address_space *mapping,
3779 struct writeback_control *wbc)
3780{
3781 struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
3782 struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
3783 struct extent_buffer *eb, *prev_eb = NULL;
3784 struct extent_page_data epd = {
3785 .bio = NULL,
3786 .tree = tree,
3787 .extent_locked = 0,
3788 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
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);
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_range_tag(&pvec, mapping, &index, end,
3818 tag))) {
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 spin_lock(&mapping->private_lock);
3829 if (!PagePrivate(page)) {
3830 spin_unlock(&mapping->private_lock);
3831 continue;
3832 }
3833
3834 eb = (struct extent_buffer *)page->private;
3835
3836 /*
3837 * Shouldn't happen and normally this would be a BUG_ON
3838 * but no sense in crashing the users box for something
3839 * we can survive anyway.
3840 */
3841 if (WARN_ON(!eb)) {
3842 spin_unlock(&mapping->private_lock);
3843 continue;
3844 }
3845
3846 if (eb == prev_eb) {
3847 spin_unlock(&mapping->private_lock);
3848 continue;
3849 }
3850
3851 ret = atomic_inc_not_zero(&eb->refs);
3852 spin_unlock(&mapping->private_lock);
3853 if (!ret)
3854 continue;
3855
3856 prev_eb = eb;
3857 ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
3858 if (!ret) {
3859 free_extent_buffer(eb);
3860 continue;
3861 }
3862
3863 ret = write_one_eb(eb, fs_info, wbc, &epd);
3864 if (ret) {
3865 done = 1;
3866 free_extent_buffer(eb);
3867 break;
3868 }
3869 free_extent_buffer(eb);
3870
3871 /*
3872 * the filesystem may choose to bump up nr_to_write.
3873 * We have to make sure to honor the new nr_to_write
3874 * at any time
3875 */
3876 nr_to_write_done = wbc->nr_to_write <= 0;
3877 }
3878 pagevec_release(&pvec);
3879 cond_resched();
3880 }
3881 if (!scanned && !done) {
3882 /*
3883 * We hit the last page and there is more work to be done: wrap
3884 * back to the start of the file
3885 */
3886 scanned = 1;
3887 index = 0;
3888 goto retry;
3889 }
3890 flush_write_bio(&epd);
3891 return ret;
3892}
3893
3894/**
3895 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3896 * @mapping: address space structure to write
3897 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
3898 * @data: data passed to __extent_writepage function
3899 *
3900 * If a page is already under I/O, write_cache_pages() skips it, even
3901 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
3902 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
3903 * and msync() need to guarantee that all the data which was dirty at the time
3904 * the call was made get new I/O started against them. If wbc->sync_mode is
3905 * WB_SYNC_ALL then we were called for data integrity and we must wait for
3906 * existing IO to complete.
3907 */
3908static int extent_write_cache_pages(struct address_space *mapping,
3909 struct writeback_control *wbc,
3910 struct extent_page_data *epd)
3911{
3912 struct inode *inode = mapping->host;
3913 int ret = 0;
3914 int done = 0;
3915 int nr_to_write_done = 0;
3916 struct pagevec pvec;
3917 int nr_pages;
3918 pgoff_t index;
3919 pgoff_t end; /* Inclusive */
3920 pgoff_t done_index;
3921 int range_whole = 0;
3922 int scanned = 0;
3923 int tag;
3924
3925 /*
3926 * We have to hold onto the inode so that ordered extents can do their
3927 * work when the IO finishes. The alternative to this is failing to add
3928 * an ordered extent if the igrab() fails there and that is a huge pain
3929 * to deal with, so instead just hold onto the inode throughout the
3930 * writepages operation. If it fails here we are freeing up the inode
3931 * anyway and we'd rather not waste our time writing out stuff that is
3932 * going to be truncated anyway.
3933 */
3934 if (!igrab(inode))
3935 return 0;
3936
3937 pagevec_init(&pvec);
3938 if (wbc->range_cyclic) {
3939 index = mapping->writeback_index; /* Start from prev offset */
3940 end = -1;
3941 } else {
3942 index = wbc->range_start >> PAGE_SHIFT;
3943 end = wbc->range_end >> PAGE_SHIFT;
3944 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
3945 range_whole = 1;
3946 scanned = 1;
3947 }
3948 if (wbc->sync_mode == WB_SYNC_ALL)
3949 tag = PAGECACHE_TAG_TOWRITE;
3950 else
3951 tag = PAGECACHE_TAG_DIRTY;
3952retry:
3953 if (wbc->sync_mode == WB_SYNC_ALL)
3954 tag_pages_for_writeback(mapping, index, end);
3955 done_index = index;
3956 while (!done && !nr_to_write_done && (index <= end) &&
3957 (nr_pages = pagevec_lookup_range_tag(&pvec, mapping,
3958 &index, end, tag))) {
3959 unsigned i;
3960
3961 scanned = 1;
3962 for (i = 0; i < nr_pages; i++) {
3963 struct page *page = pvec.pages[i];
3964
3965 done_index = page->index;
3966 /*
3967 * At this point we hold neither the i_pages lock nor
3968 * the page lock: the page may be truncated or
3969 * invalidated (changing page->mapping to NULL),
3970 * or even swizzled back from swapper_space to
3971 * tmpfs file mapping
3972 */
3973 if (!trylock_page(page)) {
3974 flush_write_bio(epd);
3975 lock_page(page);
3976 }
3977
3978 if (unlikely(page->mapping != mapping)) {
3979 unlock_page(page);
3980 continue;
3981 }
3982
3983 if (wbc->sync_mode != WB_SYNC_NONE) {
3984 if (PageWriteback(page))
3985 flush_write_bio(epd);
3986 wait_on_page_writeback(page);
3987 }
3988
3989 if (PageWriteback(page) ||
3990 !clear_page_dirty_for_io(page)) {
3991 unlock_page(page);
3992 continue;
3993 }
3994
3995 ret = __extent_writepage(page, wbc, epd);
3996
3997 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
3998 unlock_page(page);
3999 ret = 0;
4000 }
4001 if (ret < 0) {
4002 /*
4003 * done_index is set past this page,
4004 * so media errors will not choke
4005 * background writeout for the entire
4006 * file. This has consequences for
4007 * range_cyclic semantics (ie. it may
4008 * not be suitable for data integrity
4009 * writeout).
4010 */
4011 done_index = page->index + 1;
4012 done = 1;
4013 break;
4014 }
4015
4016 /*
4017 * the filesystem may choose to bump up nr_to_write.
4018 * We have to make sure to honor the new nr_to_write
4019 * at any time
4020 */
4021 nr_to_write_done = wbc->nr_to_write <= 0;
4022 }
4023 pagevec_release(&pvec);
4024 cond_resched();
4025 }
4026 if (!scanned && !done) {
4027 /*
4028 * We hit the last page and there is more work to be done: wrap
4029 * back to the start of the file
4030 */
4031 scanned = 1;
4032 index = 0;
4033 goto retry;
4034 }
4035
4036 if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
4037 mapping->writeback_index = done_index;
4038
4039 btrfs_add_delayed_iput(inode);
4040 return ret;
4041}
4042
4043static void flush_write_bio(struct extent_page_data *epd)
4044{
4045 if (epd->bio) {
4046 int ret;
4047
4048 ret = submit_one_bio(epd->bio, 0, 0);
4049 BUG_ON(ret < 0); /* -ENOMEM */
4050 epd->bio = NULL;
4051 }
4052}
4053
4054int extent_write_full_page(struct page *page, struct writeback_control *wbc)
4055{
4056 int ret;
4057 struct extent_page_data epd = {
4058 .bio = NULL,
4059 .tree = &BTRFS_I(page->mapping->host)->io_tree,
4060 .extent_locked = 0,
4061 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4062 };
4063
4064 ret = __extent_writepage(page, wbc, &epd);
4065
4066 flush_write_bio(&epd);
4067 return ret;
4068}
4069
4070int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
4071 int mode)
4072{
4073 int ret = 0;
4074 struct address_space *mapping = inode->i_mapping;
4075 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
4076 struct page *page;
4077 unsigned long nr_pages = (end - start + PAGE_SIZE) >>
4078 PAGE_SHIFT;
4079
4080 struct extent_page_data epd = {
4081 .bio = NULL,
4082 .tree = tree,
4083 .extent_locked = 1,
4084 .sync_io = mode == WB_SYNC_ALL,
4085 };
4086 struct writeback_control wbc_writepages = {
4087 .sync_mode = mode,
4088 .nr_to_write = nr_pages * 2,
4089 .range_start = start,
4090 .range_end = end + 1,
4091 };
4092
4093 while (start <= end) {
4094 page = find_get_page(mapping, start >> PAGE_SHIFT);
4095 if (clear_page_dirty_for_io(page))
4096 ret = __extent_writepage(page, &wbc_writepages, &epd);
4097 else {
4098 if (tree->ops && tree->ops->writepage_end_io_hook)
4099 tree->ops->writepage_end_io_hook(page, start,
4100 start + PAGE_SIZE - 1,
4101 NULL, 1);
4102 unlock_page(page);
4103 }
4104 put_page(page);
4105 start += PAGE_SIZE;
4106 }
4107
4108 flush_write_bio(&epd);
4109 return ret;
4110}
4111
4112int extent_writepages(struct extent_io_tree *tree,
4113 struct address_space *mapping,
4114 struct writeback_control *wbc)
4115{
4116 int ret = 0;
4117 struct extent_page_data epd = {
4118 .bio = NULL,
4119 .tree = tree,
4120 .extent_locked = 0,
4121 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4122 };
4123
4124 ret = extent_write_cache_pages(mapping, wbc, &epd);
4125 flush_write_bio(&epd);
4126 return ret;
4127}
4128
4129int extent_readpages(struct extent_io_tree *tree,
4130 struct address_space *mapping,
4131 struct list_head *pages, unsigned nr_pages)
4132{
4133 struct bio *bio = NULL;
4134 unsigned page_idx;
4135 unsigned long bio_flags = 0;
4136 struct page *pagepool[16];
4137 struct page *page;
4138 struct extent_map *em_cached = NULL;
4139 int nr = 0;
4140 u64 prev_em_start = (u64)-1;
4141
4142 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
4143 page = list_entry(pages->prev, struct page, lru);
4144
4145 prefetchw(&page->flags);
4146 list_del(&page->lru);
4147 if (add_to_page_cache_lru(page, mapping,
4148 page->index,
4149 readahead_gfp_mask(mapping))) {
4150 put_page(page);
4151 continue;
4152 }
4153
4154 pagepool[nr++] = page;
4155 if (nr < ARRAY_SIZE(pagepool))
4156 continue;
4157 __extent_readpages(tree, pagepool, nr, &em_cached, &bio,
4158 &bio_flags, &prev_em_start);
4159 nr = 0;
4160 }
4161 if (nr)
4162 __extent_readpages(tree, pagepool, nr, &em_cached, &bio,
4163 &bio_flags, &prev_em_start);
4164
4165 if (em_cached)
4166 free_extent_map(em_cached);
4167
4168 BUG_ON(!list_empty(pages));
4169 if (bio)
4170 return submit_one_bio(bio, 0, bio_flags);
4171 return 0;
4172}
4173
4174/*
4175 * basic invalidatepage code, this waits on any locked or writeback
4176 * ranges corresponding to the page, and then deletes any extent state
4177 * records from the tree
4178 */
4179int extent_invalidatepage(struct extent_io_tree *tree,
4180 struct page *page, unsigned long offset)
4181{
4182 struct extent_state *cached_state = NULL;
4183 u64 start = page_offset(page);
4184 u64 end = start + PAGE_SIZE - 1;
4185 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
4186
4187 start += ALIGN(offset, blocksize);
4188 if (start > end)
4189 return 0;
4190
4191 lock_extent_bits(tree, start, end, &cached_state);
4192 wait_on_page_writeback(page);
4193 clear_extent_bit(tree, start, end,
4194 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
4195 EXTENT_DO_ACCOUNTING,
4196 1, 1, &cached_state);
4197 return 0;
4198}
4199
4200/*
4201 * a helper for releasepage, this tests for areas of the page that
4202 * are locked or under IO and drops the related state bits if it is safe
4203 * to drop the page.
4204 */
4205static int try_release_extent_state(struct extent_map_tree *map,
4206 struct extent_io_tree *tree,
4207 struct page *page, gfp_t mask)
4208{
4209 u64 start = page_offset(page);
4210 u64 end = start + PAGE_SIZE - 1;
4211 int ret = 1;
4212
4213 if (test_range_bit(tree, start, end,
4214 EXTENT_IOBITS, 0, NULL))
4215 ret = 0;
4216 else {
4217 /*
4218 * at this point we can safely clear everything except the
4219 * locked bit and the nodatasum bit
4220 */
4221 ret = __clear_extent_bit(tree, start, end,
4222 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
4223 0, 0, NULL, mask, NULL);
4224
4225 /* if clear_extent_bit failed for enomem reasons,
4226 * we can't allow the release to continue.
4227 */
4228 if (ret < 0)
4229 ret = 0;
4230 else
4231 ret = 1;
4232 }
4233 return ret;
4234}
4235
4236/*
4237 * a helper for releasepage. As long as there are no locked extents
4238 * in the range corresponding to the page, both state records and extent
4239 * map records are removed
4240 */
4241int try_release_extent_mapping(struct extent_map_tree *map,
4242 struct extent_io_tree *tree, struct page *page,
4243 gfp_t mask)
4244{
4245 struct extent_map *em;
4246 u64 start = page_offset(page);
4247 u64 end = start + PAGE_SIZE - 1;
4248
4249 if (gfpflags_allow_blocking(mask) &&
4250 page->mapping->host->i_size > SZ_16M) {
4251 u64 len;
4252 while (start <= end) {
4253 len = end - start + 1;
4254 write_lock(&map->lock);
4255 em = lookup_extent_mapping(map, start, len);
4256 if (!em) {
4257 write_unlock(&map->lock);
4258 break;
4259 }
4260 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
4261 em->start != start) {
4262 write_unlock(&map->lock);
4263 free_extent_map(em);
4264 break;
4265 }
4266 if (!test_range_bit(tree, em->start,
4267 extent_map_end(em) - 1,
4268 EXTENT_LOCKED | EXTENT_WRITEBACK,
4269 0, NULL)) {
4270 remove_extent_mapping(map, em);
4271 /* once for the rb tree */
4272 free_extent_map(em);
4273 }
4274 start = extent_map_end(em);
4275 write_unlock(&map->lock);
4276
4277 /* once for us */
4278 free_extent_map(em);
4279 }
4280 }
4281 return try_release_extent_state(map, tree, page, mask);
4282}
4283
4284/*
4285 * helper function for fiemap, which doesn't want to see any holes.
4286 * This maps until we find something past 'last'
4287 */
4288static struct extent_map *get_extent_skip_holes(struct inode *inode,
4289 u64 offset, u64 last)
4290{
4291 u64 sectorsize = btrfs_inode_sectorsize(inode);
4292 struct extent_map *em;
4293 u64 len;
4294
4295 if (offset >= last)
4296 return NULL;
4297
4298 while (1) {
4299 len = last - offset;
4300 if (len == 0)
4301 break;
4302 len = ALIGN(len, sectorsize);
4303 em = btrfs_get_extent_fiemap(BTRFS_I(inode), NULL, 0, offset,
4304 len, 0);
4305 if (IS_ERR_OR_NULL(em))
4306 return em;
4307
4308 /* if this isn't a hole return it */
4309 if (em->block_start != EXTENT_MAP_HOLE)
4310 return em;
4311
4312 /* this is a hole, advance to the next extent */
4313 offset = extent_map_end(em);
4314 free_extent_map(em);
4315 if (offset >= last)
4316 break;
4317 }
4318 return NULL;
4319}
4320
4321/*
4322 * To cache previous fiemap extent
4323 *
4324 * Will be used for merging fiemap extent
4325 */
4326struct fiemap_cache {
4327 u64 offset;
4328 u64 phys;
4329 u64 len;
4330 u32 flags;
4331 bool cached;
4332};
4333
4334/*
4335 * Helper to submit fiemap extent.
4336 *
4337 * Will try to merge current fiemap extent specified by @offset, @phys,
4338 * @len and @flags with cached one.
4339 * And only when we fails to merge, cached one will be submitted as
4340 * fiemap extent.
4341 *
4342 * Return value is the same as fiemap_fill_next_extent().
4343 */
4344static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
4345 struct fiemap_cache *cache,
4346 u64 offset, u64 phys, u64 len, u32 flags)
4347{
4348 int ret = 0;
4349
4350 if (!cache->cached)
4351 goto assign;
4352
4353 /*
4354 * Sanity check, extent_fiemap() should have ensured that new
4355 * fiemap extent won't overlap with cahced one.
4356 * Not recoverable.
4357 *
4358 * NOTE: Physical address can overlap, due to compression
4359 */
4360 if (cache->offset + cache->len > offset) {
4361 WARN_ON(1);
4362 return -EINVAL;
4363 }
4364
4365 /*
4366 * Only merges fiemap extents if
4367 * 1) Their logical addresses are continuous
4368 *
4369 * 2) Their physical addresses are continuous
4370 * So truly compressed (physical size smaller than logical size)
4371 * extents won't get merged with each other
4372 *
4373 * 3) Share same flags except FIEMAP_EXTENT_LAST
4374 * So regular extent won't get merged with prealloc extent
4375 */
4376 if (cache->offset + cache->len == offset &&
4377 cache->phys + cache->len == phys &&
4378 (cache->flags & ~FIEMAP_EXTENT_LAST) ==
4379 (flags & ~FIEMAP_EXTENT_LAST)) {
4380 cache->len += len;
4381 cache->flags |= flags;
4382 goto try_submit_last;
4383 }
4384
4385 /* Not mergeable, need to submit cached one */
4386 ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
4387 cache->len, cache->flags);
4388 cache->cached = false;
4389 if (ret)
4390 return ret;
4391assign:
4392 cache->cached = true;
4393 cache->offset = offset;
4394 cache->phys = phys;
4395 cache->len = len;
4396 cache->flags = flags;
4397try_submit_last:
4398 if (cache->flags & FIEMAP_EXTENT_LAST) {
4399 ret = fiemap_fill_next_extent(fieinfo, cache->offset,
4400 cache->phys, cache->len, cache->flags);
4401 cache->cached = false;
4402 }
4403 return ret;
4404}
4405
4406/*
4407 * Emit last fiemap cache
4408 *
4409 * The last fiemap cache may still be cached in the following case:
4410 * 0 4k 8k
4411 * |<- Fiemap range ->|
4412 * |<------------ First extent ----------->|
4413 *
4414 * In this case, the first extent range will be cached but not emitted.
4415 * So we must emit it before ending extent_fiemap().
4416 */
4417static int emit_last_fiemap_cache(struct btrfs_fs_info *fs_info,
4418 struct fiemap_extent_info *fieinfo,
4419 struct fiemap_cache *cache)
4420{
4421 int ret;
4422
4423 if (!cache->cached)
4424 return 0;
4425
4426 ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
4427 cache->len, cache->flags);
4428 cache->cached = false;
4429 if (ret > 0)
4430 ret = 0;
4431 return ret;
4432}
4433
4434int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4435 __u64 start, __u64 len)
4436{
4437 int ret = 0;
4438 u64 off = start;
4439 u64 max = start + len;
4440 u32 flags = 0;
4441 u32 found_type;
4442 u64 last;
4443 u64 last_for_get_extent = 0;
4444 u64 disko = 0;
4445 u64 isize = i_size_read(inode);
4446 struct btrfs_key found_key;
4447 struct extent_map *em = NULL;
4448 struct extent_state *cached_state = NULL;
4449 struct btrfs_path *path;
4450 struct btrfs_root *root = BTRFS_I(inode)->root;
4451 struct fiemap_cache cache = { 0 };
4452 int end = 0;
4453 u64 em_start = 0;
4454 u64 em_len = 0;
4455 u64 em_end = 0;
4456
4457 if (len == 0)
4458 return -EINVAL;
4459
4460 path = btrfs_alloc_path();
4461 if (!path)
4462 return -ENOMEM;
4463 path->leave_spinning = 1;
4464
4465 start = round_down(start, btrfs_inode_sectorsize(inode));
4466 len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
4467
4468 /*
4469 * lookup the last file extent. We're not using i_size here
4470 * because there might be preallocation past i_size
4471 */
4472 ret = btrfs_lookup_file_extent(NULL, root, path,
4473 btrfs_ino(BTRFS_I(inode)), -1, 0);
4474 if (ret < 0) {
4475 btrfs_free_path(path);
4476 return ret;
4477 } else {
4478 WARN_ON(!ret);
4479 if (ret == 1)
4480 ret = 0;
4481 }
4482
4483 path->slots[0]--;
4484 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
4485 found_type = found_key.type;
4486
4487 /* No extents, but there might be delalloc bits */
4488 if (found_key.objectid != btrfs_ino(BTRFS_I(inode)) ||
4489 found_type != BTRFS_EXTENT_DATA_KEY) {
4490 /* have to trust i_size as the end */
4491 last = (u64)-1;
4492 last_for_get_extent = isize;
4493 } else {
4494 /*
4495 * remember the start of the last extent. There are a
4496 * bunch of different factors that go into the length of the
4497 * extent, so its much less complex to remember where it started
4498 */
4499 last = found_key.offset;
4500 last_for_get_extent = last + 1;
4501 }
4502 btrfs_release_path(path);
4503
4504 /*
4505 * we might have some extents allocated but more delalloc past those
4506 * extents. so, we trust isize unless the start of the last extent is
4507 * beyond isize
4508 */
4509 if (last < isize) {
4510 last = (u64)-1;
4511 last_for_get_extent = isize;
4512 }
4513
4514 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4515 &cached_state);
4516
4517 em = get_extent_skip_holes(inode, start, last_for_get_extent);
4518 if (!em)
4519 goto out;
4520 if (IS_ERR(em)) {
4521 ret = PTR_ERR(em);
4522 goto out;
4523 }
4524
4525 while (!end) {
4526 u64 offset_in_extent = 0;
4527
4528 /* break if the extent we found is outside the range */
4529 if (em->start >= max || extent_map_end(em) < off)
4530 break;
4531
4532 /*
4533 * get_extent may return an extent that starts before our
4534 * requested range. We have to make sure the ranges
4535 * we return to fiemap always move forward and don't
4536 * overlap, so adjust the offsets here
4537 */
4538 em_start = max(em->start, off);
4539
4540 /*
4541 * record the offset from the start of the extent
4542 * for adjusting the disk offset below. Only do this if the
4543 * extent isn't compressed since our in ram offset may be past
4544 * what we have actually allocated on disk.
4545 */
4546 if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4547 offset_in_extent = em_start - em->start;
4548 em_end = extent_map_end(em);
4549 em_len = em_end - em_start;
4550 disko = 0;
4551 flags = 0;
4552
4553 /*
4554 * bump off for our next call to get_extent
4555 */
4556 off = extent_map_end(em);
4557 if (off >= max)
4558 end = 1;
4559
4560 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
4561 end = 1;
4562 flags |= FIEMAP_EXTENT_LAST;
4563 } else if (em->block_start == EXTENT_MAP_INLINE) {
4564 flags |= (FIEMAP_EXTENT_DATA_INLINE |
4565 FIEMAP_EXTENT_NOT_ALIGNED);
4566 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
4567 flags |= (FIEMAP_EXTENT_DELALLOC |
4568 FIEMAP_EXTENT_UNKNOWN);
4569 } else if (fieinfo->fi_extents_max) {
4570 u64 bytenr = em->block_start -
4571 (em->start - em->orig_start);
4572
4573 disko = em->block_start + offset_in_extent;
4574
4575 /*
4576 * As btrfs supports shared space, this information
4577 * can be exported to userspace tools via
4578 * flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0
4579 * then we're just getting a count and we can skip the
4580 * lookup stuff.
4581 */
4582 ret = btrfs_check_shared(root,
4583 btrfs_ino(BTRFS_I(inode)),
4584 bytenr);
4585 if (ret < 0)
4586 goto out_free;
4587 if (ret)
4588 flags |= FIEMAP_EXTENT_SHARED;
4589 ret = 0;
4590 }
4591 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4592 flags |= FIEMAP_EXTENT_ENCODED;
4593 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
4594 flags |= FIEMAP_EXTENT_UNWRITTEN;
4595
4596 free_extent_map(em);
4597 em = NULL;
4598 if ((em_start >= last) || em_len == (u64)-1 ||
4599 (last == (u64)-1 && isize <= em_end)) {
4600 flags |= FIEMAP_EXTENT_LAST;
4601 end = 1;
4602 }
4603
4604 /* now scan forward to see if this is really the last extent. */
4605 em = get_extent_skip_holes(inode, off, last_for_get_extent);
4606 if (IS_ERR(em)) {
4607 ret = PTR_ERR(em);
4608 goto out;
4609 }
4610 if (!em) {
4611 flags |= FIEMAP_EXTENT_LAST;
4612 end = 1;
4613 }
4614 ret = emit_fiemap_extent(fieinfo, &cache, em_start, disko,
4615 em_len, flags);
4616 if (ret) {
4617 if (ret == 1)
4618 ret = 0;
4619 goto out_free;
4620 }
4621 }
4622out_free:
4623 if (!ret)
4624 ret = emit_last_fiemap_cache(root->fs_info, fieinfo, &cache);
4625 free_extent_map(em);
4626out:
4627 btrfs_free_path(path);
4628 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4629 &cached_state);
4630 return ret;
4631}
4632
4633static void __free_extent_buffer(struct extent_buffer *eb)
4634{
4635 btrfs_leak_debug_del(&eb->leak_list);
4636 kmem_cache_free(extent_buffer_cache, eb);
4637}
4638
4639int extent_buffer_under_io(struct extent_buffer *eb)
4640{
4641 return (atomic_read(&eb->io_pages) ||
4642 test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
4643 test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4644}
4645
4646/*
4647 * Helper for releasing extent buffer page.
4648 */
4649static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
4650{
4651 unsigned long index;
4652 struct page *page;
4653 int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4654
4655 BUG_ON(extent_buffer_under_io(eb));
4656
4657 index = num_extent_pages(eb->start, eb->len);
4658 if (index == 0)
4659 return;
4660
4661 do {
4662 index--;
4663 page = eb->pages[index];
4664 if (!page)
4665 continue;
4666 if (mapped)
4667 spin_lock(&page->mapping->private_lock);
4668 /*
4669 * We do this since we'll remove the pages after we've
4670 * removed the eb from the radix tree, so we could race
4671 * and have this page now attached to the new eb. So
4672 * only clear page_private if it's still connected to
4673 * this eb.
4674 */
4675 if (PagePrivate(page) &&
4676 page->private == (unsigned long)eb) {
4677 BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4678 BUG_ON(PageDirty(page));
4679 BUG_ON(PageWriteback(page));
4680 /*
4681 * We need to make sure we haven't be attached
4682 * to a new eb.
4683 */
4684 ClearPagePrivate(page);
4685 set_page_private(page, 0);
4686 /* One for the page private */
4687 put_page(page);
4688 }
4689
4690 if (mapped)
4691 spin_unlock(&page->mapping->private_lock);
4692
4693 /* One for when we allocated the page */
4694 put_page(page);
4695 } while (index != 0);
4696}
4697
4698/*
4699 * Helper for releasing the extent buffer.
4700 */
4701static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
4702{
4703 btrfs_release_extent_buffer_page(eb);
4704 __free_extent_buffer(eb);
4705}
4706
4707static struct extent_buffer *
4708__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
4709 unsigned long len)
4710{
4711 struct extent_buffer *eb = NULL;
4712
4713 eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
4714 eb->start = start;
4715 eb->len = len;
4716 eb->fs_info = fs_info;
4717 eb->bflags = 0;
4718 rwlock_init(&eb->lock);
4719 atomic_set(&eb->write_locks, 0);
4720 atomic_set(&eb->read_locks, 0);
4721 atomic_set(&eb->blocking_readers, 0);
4722 atomic_set(&eb->blocking_writers, 0);
4723 atomic_set(&eb->spinning_readers, 0);
4724 atomic_set(&eb->spinning_writers, 0);
4725 eb->lock_nested = 0;
4726 init_waitqueue_head(&eb->write_lock_wq);
4727 init_waitqueue_head(&eb->read_lock_wq);
4728
4729 btrfs_leak_debug_add(&eb->leak_list, &buffers);
4730
4731 spin_lock_init(&eb->refs_lock);
4732 atomic_set(&eb->refs, 1);
4733 atomic_set(&eb->io_pages, 0);
4734
4735 /*
4736 * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
4737 */
4738 BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
4739 > MAX_INLINE_EXTENT_BUFFER_SIZE);
4740 BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
4741
4742 return eb;
4743}
4744
4745struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
4746{
4747 unsigned long i;
4748 struct page *p;
4749 struct extent_buffer *new;
4750 unsigned long num_pages = num_extent_pages(src->start, src->len);
4751
4752 new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
4753 if (new == NULL)
4754 return NULL;
4755
4756 for (i = 0; i < num_pages; i++) {
4757 p = alloc_page(GFP_NOFS);
4758 if (!p) {
4759 btrfs_release_extent_buffer(new);
4760 return NULL;
4761 }
4762 attach_extent_buffer_page(new, p);
4763 WARN_ON(PageDirty(p));
4764 SetPageUptodate(p);
4765 new->pages[i] = p;
4766 copy_page(page_address(p), page_address(src->pages[i]));
4767 }
4768
4769 set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
4770 set_bit(EXTENT_BUFFER_DUMMY, &new->bflags);
4771
4772 return new;
4773}
4774
4775struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4776 u64 start, unsigned long len)
4777{
4778 struct extent_buffer *eb;
4779 unsigned long num_pages;
4780 unsigned long i;
4781
4782 num_pages = num_extent_pages(start, len);
4783
4784 eb = __alloc_extent_buffer(fs_info, start, len);
4785 if (!eb)
4786 return NULL;
4787
4788 for (i = 0; i < num_pages; i++) {
4789 eb->pages[i] = alloc_page(GFP_NOFS);
4790 if (!eb->pages[i])
4791 goto err;
4792 }
4793 set_extent_buffer_uptodate(eb);
4794 btrfs_set_header_nritems(eb, 0);
4795 set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4796
4797 return eb;
4798err:
4799 for (; i > 0; i--)
4800 __free_page(eb->pages[i - 1]);
4801 __free_extent_buffer(eb);
4802 return NULL;
4803}
4804
4805struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4806 u64 start)
4807{
4808 return __alloc_dummy_extent_buffer(fs_info, start, fs_info->nodesize);
4809}
4810
4811static void check_buffer_tree_ref(struct extent_buffer *eb)
4812{
4813 int refs;
4814 /* the ref bit is tricky. We have to make sure it is set
4815 * if we have the buffer dirty. Otherwise the
4816 * code to free a buffer can end up dropping a dirty
4817 * page
4818 *
4819 * Once the ref bit is set, it won't go away while the
4820 * buffer is dirty or in writeback, and it also won't
4821 * go away while we have the reference count on the
4822 * eb bumped.
4823 *
4824 * We can't just set the ref bit without bumping the
4825 * ref on the eb because free_extent_buffer might
4826 * see the ref bit and try to clear it. If this happens
4827 * free_extent_buffer might end up dropping our original
4828 * ref by mistake and freeing the page before we are able
4829 * to add one more ref.
4830 *
4831 * So bump the ref count first, then set the bit. If someone
4832 * beat us to it, drop the ref we added.
4833 */
4834 refs = atomic_read(&eb->refs);
4835 if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4836 return;
4837
4838 spin_lock(&eb->refs_lock);
4839 if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4840 atomic_inc(&eb->refs);
4841 spin_unlock(&eb->refs_lock);
4842}
4843
4844static void mark_extent_buffer_accessed(struct extent_buffer *eb,
4845 struct page *accessed)
4846{
4847 unsigned long num_pages, i;
4848
4849 check_buffer_tree_ref(eb);
4850
4851 num_pages = num_extent_pages(eb->start, eb->len);
4852 for (i = 0; i < num_pages; i++) {
4853 struct page *p = eb->pages[i];
4854
4855 if (p != accessed)
4856 mark_page_accessed(p);
4857 }
4858}
4859
4860struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
4861 u64 start)
4862{
4863 struct extent_buffer *eb;
4864
4865 rcu_read_lock();
4866 eb = radix_tree_lookup(&fs_info->buffer_radix,
4867 start >> PAGE_SHIFT);
4868 if (eb && atomic_inc_not_zero(&eb->refs)) {
4869 rcu_read_unlock();
4870 /*
4871 * Lock our eb's refs_lock to avoid races with
4872 * free_extent_buffer. When we get our eb it might be flagged
4873 * with EXTENT_BUFFER_STALE and another task running
4874 * free_extent_buffer might have seen that flag set,
4875 * eb->refs == 2, that the buffer isn't under IO (dirty and
4876 * writeback flags not set) and it's still in the tree (flag
4877 * EXTENT_BUFFER_TREE_REF set), therefore being in the process
4878 * of decrementing the extent buffer's reference count twice.
4879 * So here we could race and increment the eb's reference count,
4880 * clear its stale flag, mark it as dirty and drop our reference
4881 * before the other task finishes executing free_extent_buffer,
4882 * which would later result in an attempt to free an extent
4883 * buffer that is dirty.
4884 */
4885 if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
4886 spin_lock(&eb->refs_lock);
4887 spin_unlock(&eb->refs_lock);
4888 }
4889 mark_extent_buffer_accessed(eb, NULL);
4890 return eb;
4891 }
4892 rcu_read_unlock();
4893
4894 return NULL;
4895}
4896
4897#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4898struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
4899 u64 start)
4900{
4901 struct extent_buffer *eb, *exists = NULL;
4902 int ret;
4903
4904 eb = find_extent_buffer(fs_info, start);
4905 if (eb)
4906 return eb;
4907 eb = alloc_dummy_extent_buffer(fs_info, start);
4908 if (!eb)
4909 return NULL;
4910 eb->fs_info = fs_info;
4911again:
4912 ret = radix_tree_preload(GFP_NOFS);
4913 if (ret)
4914 goto free_eb;
4915 spin_lock(&fs_info->buffer_lock);
4916 ret = radix_tree_insert(&fs_info->buffer_radix,
4917 start >> PAGE_SHIFT, eb);
4918 spin_unlock(&fs_info->buffer_lock);
4919 radix_tree_preload_end();
4920 if (ret == -EEXIST) {
4921 exists = find_extent_buffer(fs_info, start);
4922 if (exists)
4923 goto free_eb;
4924 else
4925 goto again;
4926 }
4927 check_buffer_tree_ref(eb);
4928 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4929
4930 /*
4931 * We will free dummy extent buffer's if they come into
4932 * free_extent_buffer with a ref count of 2, but if we are using this we
4933 * want the buffers to stay in memory until we're done with them, so
4934 * bump the ref count again.
4935 */
4936 atomic_inc(&eb->refs);
4937 return eb;
4938free_eb:
4939 btrfs_release_extent_buffer(eb);
4940 return exists;
4941}
4942#endif
4943
4944struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4945 u64 start)
4946{
4947 unsigned long len = fs_info->nodesize;
4948 unsigned long num_pages = num_extent_pages(start, len);
4949 unsigned long i;
4950 unsigned long index = start >> PAGE_SHIFT;
4951 struct extent_buffer *eb;
4952 struct extent_buffer *exists = NULL;
4953 struct page *p;
4954 struct address_space *mapping = fs_info->btree_inode->i_mapping;
4955 int uptodate = 1;
4956 int ret;
4957
4958 if (!IS_ALIGNED(start, fs_info->sectorsize)) {
4959 btrfs_err(fs_info, "bad tree block start %llu", start);
4960 return ERR_PTR(-EINVAL);
4961 }
4962
4963 eb = find_extent_buffer(fs_info, start);
4964 if (eb)
4965 return eb;
4966
4967 eb = __alloc_extent_buffer(fs_info, start, len);
4968 if (!eb)
4969 return ERR_PTR(-ENOMEM);
4970
4971 for (i = 0; i < num_pages; i++, index++) {
4972 p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
4973 if (!p) {
4974 exists = ERR_PTR(-ENOMEM);
4975 goto free_eb;
4976 }
4977
4978 spin_lock(&mapping->private_lock);
4979 if (PagePrivate(p)) {
4980 /*
4981 * We could have already allocated an eb for this page
4982 * and attached one so lets see if we can get a ref on
4983 * the existing eb, and if we can we know it's good and
4984 * we can just return that one, else we know we can just
4985 * overwrite page->private.
4986 */
4987 exists = (struct extent_buffer *)p->private;
4988 if (atomic_inc_not_zero(&exists->refs)) {
4989 spin_unlock(&mapping->private_lock);
4990 unlock_page(p);
4991 put_page(p);
4992 mark_extent_buffer_accessed(exists, p);
4993 goto free_eb;
4994 }
4995 exists = NULL;
4996
4997 /*
4998 * Do this so attach doesn't complain and we need to
4999 * drop the ref the old guy had.
5000 */
5001 ClearPagePrivate(p);
5002 WARN_ON(PageDirty(p));
5003 put_page(p);
5004 }
5005 attach_extent_buffer_page(eb, p);
5006 spin_unlock(&mapping->private_lock);
5007 WARN_ON(PageDirty(p));
5008 eb->pages[i] = p;
5009 if (!PageUptodate(p))
5010 uptodate = 0;
5011
5012 /*
5013 * see below about how we avoid a nasty race with release page
5014 * and why we unlock later
5015 */
5016 }
5017 if (uptodate)
5018 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5019again:
5020 ret = radix_tree_preload(GFP_NOFS);
5021 if (ret) {
5022 exists = ERR_PTR(ret);
5023 goto free_eb;
5024 }
5025
5026 spin_lock(&fs_info->buffer_lock);
5027 ret = radix_tree_insert(&fs_info->buffer_radix,
5028 start >> PAGE_SHIFT, eb);
5029 spin_unlock(&fs_info->buffer_lock);
5030 radix_tree_preload_end();
5031 if (ret == -EEXIST) {
5032 exists = find_extent_buffer(fs_info, start);
5033 if (exists)
5034 goto free_eb;
5035 else
5036 goto again;
5037 }
5038 /* add one reference for the tree */
5039 check_buffer_tree_ref(eb);
5040 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
5041
5042 /*
5043 * there is a race where release page may have
5044 * tried to find this extent buffer in the radix
5045 * but failed. It will tell the VM it is safe to
5046 * reclaim the, and it will clear the page private bit.
5047 * We must make sure to set the page private bit properly
5048 * after the extent buffer is in the radix tree so
5049 * it doesn't get lost
5050 */
5051 SetPageChecked(eb->pages[0]);
5052 for (i = 1; i < num_pages; i++) {
5053 p = eb->pages[i];
5054 ClearPageChecked(p);
5055 unlock_page(p);
5056 }
5057 unlock_page(eb->pages[0]);
5058 return eb;
5059
5060free_eb:
5061 WARN_ON(!atomic_dec_and_test(&eb->refs));
5062 for (i = 0; i < num_pages; i++) {
5063 if (eb->pages[i])
5064 unlock_page(eb->pages[i]);
5065 }
5066
5067 btrfs_release_extent_buffer(eb);
5068 return exists;
5069}
5070
5071static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
5072{
5073 struct extent_buffer *eb =
5074 container_of(head, struct extent_buffer, rcu_head);
5075
5076 __free_extent_buffer(eb);
5077}
5078
5079/* Expects to have eb->eb_lock already held */
5080static int release_extent_buffer(struct extent_buffer *eb)
5081{
5082 WARN_ON(atomic_read(&eb->refs) == 0);
5083 if (atomic_dec_and_test(&eb->refs)) {
5084 if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
5085 struct btrfs_fs_info *fs_info = eb->fs_info;
5086
5087 spin_unlock(&eb->refs_lock);
5088
5089 spin_lock(&fs_info->buffer_lock);
5090 radix_tree_delete(&fs_info->buffer_radix,
5091 eb->start >> PAGE_SHIFT);
5092 spin_unlock(&fs_info->buffer_lock);
5093 } else {
5094 spin_unlock(&eb->refs_lock);
5095 }
5096
5097 /* Should be safe to release our pages at this point */
5098 btrfs_release_extent_buffer_page(eb);
5099#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5100 if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))) {
5101 __free_extent_buffer(eb);
5102 return 1;
5103 }
5104#endif
5105 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
5106 return 1;
5107 }
5108 spin_unlock(&eb->refs_lock);
5109
5110 return 0;
5111}
5112
5113void free_extent_buffer(struct extent_buffer *eb)
5114{
5115 int refs;
5116 int old;
5117 if (!eb)
5118 return;
5119
5120 while (1) {
5121 refs = atomic_read(&eb->refs);
5122 if (refs <= 3)
5123 break;
5124 old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
5125 if (old == refs)
5126 return;
5127 }
5128
5129 spin_lock(&eb->refs_lock);
5130 if (atomic_read(&eb->refs) == 2 &&
5131 test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
5132 atomic_dec(&eb->refs);
5133
5134 if (atomic_read(&eb->refs) == 2 &&
5135 test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
5136 !extent_buffer_under_io(eb) &&
5137 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5138 atomic_dec(&eb->refs);
5139
5140 /*
5141 * I know this is terrible, but it's temporary until we stop tracking
5142 * the uptodate bits and such for the extent buffers.
5143 */
5144 release_extent_buffer(eb);
5145}
5146
5147void free_extent_buffer_stale(struct extent_buffer *eb)
5148{
5149 if (!eb)
5150 return;
5151
5152 spin_lock(&eb->refs_lock);
5153 set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
5154
5155 if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
5156 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5157 atomic_dec(&eb->refs);
5158 release_extent_buffer(eb);
5159}
5160
5161void clear_extent_buffer_dirty(struct extent_buffer *eb)
5162{
5163 unsigned long i;
5164 unsigned long num_pages;
5165 struct page *page;
5166
5167 num_pages = num_extent_pages(eb->start, eb->len);
5168
5169 for (i = 0; i < num_pages; i++) {
5170 page = eb->pages[i];
5171 if (!PageDirty(page))
5172 continue;
5173
5174 lock_page(page);
5175 WARN_ON(!PagePrivate(page));
5176
5177 clear_page_dirty_for_io(page);
5178 xa_lock_irq(&page->mapping->i_pages);
5179 if (!PageDirty(page)) {
5180 radix_tree_tag_clear(&page->mapping->i_pages,
5181 page_index(page),
5182 PAGECACHE_TAG_DIRTY);
5183 }
5184 xa_unlock_irq(&page->mapping->i_pages);
5185 ClearPageError(page);
5186 unlock_page(page);
5187 }
5188 WARN_ON(atomic_read(&eb->refs) == 0);
5189}
5190
5191int set_extent_buffer_dirty(struct extent_buffer *eb)
5192{
5193 unsigned long i;
5194 unsigned long num_pages;
5195 int was_dirty = 0;
5196
5197 check_buffer_tree_ref(eb);
5198
5199 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
5200
5201 num_pages = num_extent_pages(eb->start, eb->len);
5202 WARN_ON(atomic_read(&eb->refs) == 0);
5203 WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
5204
5205 for (i = 0; i < num_pages; i++)
5206 set_page_dirty(eb->pages[i]);
5207 return was_dirty;
5208}
5209
5210void clear_extent_buffer_uptodate(struct extent_buffer *eb)
5211{
5212 unsigned long i;
5213 struct page *page;
5214 unsigned long num_pages;
5215
5216 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5217 num_pages = num_extent_pages(eb->start, eb->len);
5218 for (i = 0; i < num_pages; i++) {
5219 page = eb->pages[i];
5220 if (page)
5221 ClearPageUptodate(page);
5222 }
5223}
5224
5225void set_extent_buffer_uptodate(struct extent_buffer *eb)
5226{
5227 unsigned long i;
5228 struct page *page;
5229 unsigned long num_pages;
5230
5231 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5232 num_pages = num_extent_pages(eb->start, eb->len);
5233 for (i = 0; i < num_pages; i++) {
5234 page = eb->pages[i];
5235 SetPageUptodate(page);
5236 }
5237}
5238
5239int read_extent_buffer_pages(struct extent_io_tree *tree,
5240 struct extent_buffer *eb, int wait, int mirror_num)
5241{
5242 unsigned long i;
5243 struct page *page;
5244 int err;
5245 int ret = 0;
5246 int locked_pages = 0;
5247 int all_uptodate = 1;
5248 unsigned long num_pages;
5249 unsigned long num_reads = 0;
5250 struct bio *bio = NULL;
5251 unsigned long bio_flags = 0;
5252
5253 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
5254 return 0;
5255
5256 num_pages = num_extent_pages(eb->start, eb->len);
5257 for (i = 0; i < num_pages; i++) {
5258 page = eb->pages[i];
5259 if (wait == WAIT_NONE) {
5260 if (!trylock_page(page))
5261 goto unlock_exit;
5262 } else {
5263 lock_page(page);
5264 }
5265 locked_pages++;
5266 }
5267 /*
5268 * We need to firstly lock all pages to make sure that
5269 * the uptodate bit of our pages won't be affected by
5270 * clear_extent_buffer_uptodate().
5271 */
5272 for (i = 0; i < num_pages; i++) {
5273 page = eb->pages[i];
5274 if (!PageUptodate(page)) {
5275 num_reads++;
5276 all_uptodate = 0;
5277 }
5278 }
5279
5280 if (all_uptodate) {
5281 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5282 goto unlock_exit;
5283 }
5284
5285 clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
5286 eb->read_mirror = 0;
5287 atomic_set(&eb->io_pages, num_reads);
5288 for (i = 0; i < num_pages; i++) {
5289 page = eb->pages[i];
5290
5291 if (!PageUptodate(page)) {
5292 if (ret) {
5293 atomic_dec(&eb->io_pages);
5294 unlock_page(page);
5295 continue;
5296 }
5297
5298 ClearPageError(page);
5299 err = __extent_read_full_page(tree, page,
5300 btree_get_extent, &bio,
5301 mirror_num, &bio_flags,
5302 REQ_META);
5303 if (err) {
5304 ret = err;
5305 /*
5306 * We use &bio in above __extent_read_full_page,
5307 * so we ensure that if it returns error, the
5308 * current page fails to add itself to bio and
5309 * it's been unlocked.
5310 *
5311 * We must dec io_pages by ourselves.
5312 */
5313 atomic_dec(&eb->io_pages);
5314 }
5315 } else {
5316 unlock_page(page);
5317 }
5318 }
5319
5320 if (bio) {
5321 err = submit_one_bio(bio, mirror_num, bio_flags);
5322 if (err)
5323 return err;
5324 }
5325
5326 if (ret || wait != WAIT_COMPLETE)
5327 return ret;
5328
5329 for (i = 0; i < num_pages; i++) {
5330 page = eb->pages[i];
5331 wait_on_page_locked(page);
5332 if (!PageUptodate(page))
5333 ret = -EIO;
5334 }
5335
5336 return ret;
5337
5338unlock_exit:
5339 while (locked_pages > 0) {
5340 locked_pages--;
5341 page = eb->pages[locked_pages];
5342 unlock_page(page);
5343 }
5344 return ret;
5345}
5346
5347void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
5348 unsigned long start, unsigned long len)
5349{
5350 size_t cur;
5351 size_t offset;
5352 struct page *page;
5353 char *kaddr;
5354 char *dst = (char *)dstv;
5355 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5356 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5357
5358 if (start + len > eb->len) {
5359 WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
5360 eb->start, eb->len, start, len);
5361 memset(dst, 0, len);
5362 return;
5363 }
5364
5365 offset = (start_offset + start) & (PAGE_SIZE - 1);
5366
5367 while (len > 0) {
5368 page = eb->pages[i];
5369
5370 cur = min(len, (PAGE_SIZE - offset));
5371 kaddr = page_address(page);
5372 memcpy(dst, kaddr + offset, cur);
5373
5374 dst += cur;
5375 len -= cur;
5376 offset = 0;
5377 i++;
5378 }
5379}
5380
5381int read_extent_buffer_to_user(const struct extent_buffer *eb,
5382 void __user *dstv,
5383 unsigned long start, unsigned long len)
5384{
5385 size_t cur;
5386 size_t offset;
5387 struct page *page;
5388 char *kaddr;
5389 char __user *dst = (char __user *)dstv;
5390 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5391 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5392 int ret = 0;
5393
5394 WARN_ON(start > eb->len);
5395 WARN_ON(start + len > eb->start + eb->len);
5396
5397 offset = (start_offset + start) & (PAGE_SIZE - 1);
5398
5399 while (len > 0) {
5400 page = eb->pages[i];
5401
5402 cur = min(len, (PAGE_SIZE - offset));
5403 kaddr = page_address(page);
5404 if (copy_to_user(dst, kaddr + offset, cur)) {
5405 ret = -EFAULT;
5406 break;
5407 }
5408
5409 dst += cur;
5410 len -= cur;
5411 offset = 0;
5412 i++;
5413 }
5414
5415 return ret;
5416}
5417
5418/*
5419 * return 0 if the item is found within a page.
5420 * return 1 if the item spans two pages.
5421 * return -EINVAL otherwise.
5422 */
5423int map_private_extent_buffer(const struct extent_buffer *eb,
5424 unsigned long start, unsigned long min_len,
5425 char **map, unsigned long *map_start,
5426 unsigned long *map_len)
5427{
5428 size_t offset = start & (PAGE_SIZE - 1);
5429 char *kaddr;
5430 struct page *p;
5431 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5432 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5433 unsigned long end_i = (start_offset + start + min_len - 1) >>
5434 PAGE_SHIFT;
5435
5436 if (start + min_len > eb->len) {
5437 WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
5438 eb->start, eb->len, start, min_len);
5439 return -EINVAL;
5440 }
5441
5442 if (i != end_i)
5443 return 1;
5444
5445 if (i == 0) {
5446 offset = start_offset;
5447 *map_start = 0;
5448 } else {
5449 offset = 0;
5450 *map_start = ((u64)i << PAGE_SHIFT) - start_offset;
5451 }
5452
5453 p = eb->pages[i];
5454 kaddr = page_address(p);
5455 *map = kaddr + offset;
5456 *map_len = PAGE_SIZE - offset;
5457 return 0;
5458}
5459
5460int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
5461 unsigned long start, unsigned long len)
5462{
5463 size_t cur;
5464 size_t offset;
5465 struct page *page;
5466 char *kaddr;
5467 char *ptr = (char *)ptrv;
5468 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5469 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5470 int ret = 0;
5471
5472 WARN_ON(start > eb->len);
5473 WARN_ON(start + len > eb->start + eb->len);
5474
5475 offset = (start_offset + start) & (PAGE_SIZE - 1);
5476
5477 while (len > 0) {
5478 page = eb->pages[i];
5479
5480 cur = min(len, (PAGE_SIZE - offset));
5481
5482 kaddr = page_address(page);
5483 ret = memcmp(ptr, kaddr + offset, cur);
5484 if (ret)
5485 break;
5486
5487 ptr += cur;
5488 len -= cur;
5489 offset = 0;
5490 i++;
5491 }
5492 return ret;
5493}
5494
5495void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
5496 const void *srcv)
5497{
5498 char *kaddr;
5499
5500 WARN_ON(!PageUptodate(eb->pages[0]));
5501 kaddr = page_address(eb->pages[0]);
5502 memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,
5503 BTRFS_FSID_SIZE);
5504}
5505
5506void write_extent_buffer_fsid(struct extent_buffer *eb, const void *srcv)
5507{
5508 char *kaddr;
5509
5510 WARN_ON(!PageUptodate(eb->pages[0]));
5511 kaddr = page_address(eb->pages[0]);
5512 memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,
5513 BTRFS_FSID_SIZE);
5514}
5515
5516void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
5517 unsigned long start, unsigned long len)
5518{
5519 size_t cur;
5520 size_t offset;
5521 struct page *page;
5522 char *kaddr;
5523 char *src = (char *)srcv;
5524 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5525 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5526
5527 WARN_ON(start > eb->len);
5528 WARN_ON(start + len > eb->start + eb->len);
5529
5530 offset = (start_offset + start) & (PAGE_SIZE - 1);
5531
5532 while (len > 0) {
5533 page = eb->pages[i];
5534 WARN_ON(!PageUptodate(page));
5535
5536 cur = min(len, PAGE_SIZE - offset);
5537 kaddr = page_address(page);
5538 memcpy(kaddr + offset, src, cur);
5539
5540 src += cur;
5541 len -= cur;
5542 offset = 0;
5543 i++;
5544 }
5545}
5546
5547void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
5548 unsigned long len)
5549{
5550 size_t cur;
5551 size_t offset;
5552 struct page *page;
5553 char *kaddr;
5554 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5555 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5556
5557 WARN_ON(start > eb->len);
5558 WARN_ON(start + len > eb->start + eb->len);
5559
5560 offset = (start_offset + start) & (PAGE_SIZE - 1);
5561
5562 while (len > 0) {
5563 page = eb->pages[i];
5564 WARN_ON(!PageUptodate(page));
5565
5566 cur = min(len, PAGE_SIZE - offset);
5567 kaddr = page_address(page);
5568 memset(kaddr + offset, 0, cur);
5569
5570 len -= cur;
5571 offset = 0;
5572 i++;
5573 }
5574}
5575
5576void copy_extent_buffer_full(struct extent_buffer *dst,
5577 struct extent_buffer *src)
5578{
5579 int i;
5580 unsigned num_pages;
5581
5582 ASSERT(dst->len == src->len);
5583
5584 num_pages = num_extent_pages(dst->start, dst->len);
5585 for (i = 0; i < num_pages; i++)
5586 copy_page(page_address(dst->pages[i]),
5587 page_address(src->pages[i]));
5588}
5589
5590void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
5591 unsigned long dst_offset, unsigned long src_offset,
5592 unsigned long len)
5593{
5594 u64 dst_len = dst->len;
5595 size_t cur;
5596 size_t offset;
5597 struct page *page;
5598 char *kaddr;
5599 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5600 unsigned long i = (start_offset + dst_offset) >> PAGE_SHIFT;
5601
5602 WARN_ON(src->len != dst_len);
5603
5604 offset = (start_offset + dst_offset) &
5605 (PAGE_SIZE - 1);
5606
5607 while (len > 0) {
5608 page = dst->pages[i];
5609 WARN_ON(!PageUptodate(page));
5610
5611 cur = min(len, (unsigned long)(PAGE_SIZE - offset));
5612
5613 kaddr = page_address(page);
5614 read_extent_buffer(src, kaddr + offset, src_offset, cur);
5615
5616 src_offset += cur;
5617 len -= cur;
5618 offset = 0;
5619 i++;
5620 }
5621}
5622
5623void le_bitmap_set(u8 *map, unsigned int start, int len)
5624{
5625 u8 *p = map + BIT_BYTE(start);
5626 const unsigned int size = start + len;
5627 int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
5628 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
5629
5630 while (len - bits_to_set >= 0) {
5631 *p |= mask_to_set;
5632 len -= bits_to_set;
5633 bits_to_set = BITS_PER_BYTE;
5634 mask_to_set = ~0;
5635 p++;
5636 }
5637 if (len) {
5638 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5639 *p |= mask_to_set;
5640 }
5641}
5642
5643void le_bitmap_clear(u8 *map, unsigned int start, int len)
5644{
5645 u8 *p = map + BIT_BYTE(start);
5646 const unsigned int size = start + len;
5647 int bits_to_clear = BITS_PER_BYTE - (start % BITS_PER_BYTE);
5648 u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(start);
5649
5650 while (len - bits_to_clear >= 0) {
5651 *p &= ~mask_to_clear;
5652 len -= bits_to_clear;
5653 bits_to_clear = BITS_PER_BYTE;
5654 mask_to_clear = ~0;
5655 p++;
5656 }
5657 if (len) {
5658 mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5659 *p &= ~mask_to_clear;
5660 }
5661}
5662
5663/*
5664 * eb_bitmap_offset() - calculate the page and offset of the byte containing the
5665 * given bit number
5666 * @eb: the extent buffer
5667 * @start: offset of the bitmap item in the extent buffer
5668 * @nr: bit number
5669 * @page_index: return index of the page in the extent buffer that contains the
5670 * given bit number
5671 * @page_offset: return offset into the page given by page_index
5672 *
5673 * This helper hides the ugliness of finding the byte in an extent buffer which
5674 * contains a given bit.
5675 */
5676static inline void eb_bitmap_offset(struct extent_buffer *eb,
5677 unsigned long start, unsigned long nr,
5678 unsigned long *page_index,
5679 size_t *page_offset)
5680{
5681 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5682 size_t byte_offset = BIT_BYTE(nr);
5683 size_t offset;
5684
5685 /*
5686 * The byte we want is the offset of the extent buffer + the offset of
5687 * the bitmap item in the extent buffer + the offset of the byte in the
5688 * bitmap item.
5689 */
5690 offset = start_offset + start + byte_offset;
5691
5692 *page_index = offset >> PAGE_SHIFT;
5693 *page_offset = offset & (PAGE_SIZE - 1);
5694}
5695
5696/**
5697 * extent_buffer_test_bit - determine whether a bit in a bitmap item is set
5698 * @eb: the extent buffer
5699 * @start: offset of the bitmap item in the extent buffer
5700 * @nr: bit number to test
5701 */
5702int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
5703 unsigned long nr)
5704{
5705 u8 *kaddr;
5706 struct page *page;
5707 unsigned long i;
5708 size_t offset;
5709
5710 eb_bitmap_offset(eb, start, nr, &i, &offset);
5711 page = eb->pages[i];
5712 WARN_ON(!PageUptodate(page));
5713 kaddr = page_address(page);
5714 return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
5715}
5716
5717/**
5718 * extent_buffer_bitmap_set - set an area of a bitmap
5719 * @eb: the extent buffer
5720 * @start: offset of the bitmap item in the extent buffer
5721 * @pos: bit number of the first bit
5722 * @len: number of bits to set
5723 */
5724void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
5725 unsigned long pos, unsigned long len)
5726{
5727 u8 *kaddr;
5728 struct page *page;
5729 unsigned long i;
5730 size_t offset;
5731 const unsigned int size = pos + len;
5732 int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5733 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
5734
5735 eb_bitmap_offset(eb, start, pos, &i, &offset);
5736 page = eb->pages[i];
5737 WARN_ON(!PageUptodate(page));
5738 kaddr = page_address(page);
5739
5740 while (len >= bits_to_set) {
5741 kaddr[offset] |= mask_to_set;
5742 len -= bits_to_set;
5743 bits_to_set = BITS_PER_BYTE;
5744 mask_to_set = ~0;
5745 if (++offset >= PAGE_SIZE && len > 0) {
5746 offset = 0;
5747 page = eb->pages[++i];
5748 WARN_ON(!PageUptodate(page));
5749 kaddr = page_address(page);
5750 }
5751 }
5752 if (len) {
5753 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5754 kaddr[offset] |= mask_to_set;
5755 }
5756}
5757
5758
5759/**
5760 * extent_buffer_bitmap_clear - clear an area of a bitmap
5761 * @eb: the extent buffer
5762 * @start: offset of the bitmap item in the extent buffer
5763 * @pos: bit number of the first bit
5764 * @len: number of bits to clear
5765 */
5766void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
5767 unsigned long pos, unsigned long len)
5768{
5769 u8 *kaddr;
5770 struct page *page;
5771 unsigned long i;
5772 size_t offset;
5773 const unsigned int size = pos + len;
5774 int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5775 u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
5776
5777 eb_bitmap_offset(eb, start, pos, &i, &offset);
5778 page = eb->pages[i];
5779 WARN_ON(!PageUptodate(page));
5780 kaddr = page_address(page);
5781
5782 while (len >= bits_to_clear) {
5783 kaddr[offset] &= ~mask_to_clear;
5784 len -= bits_to_clear;
5785 bits_to_clear = BITS_PER_BYTE;
5786 mask_to_clear = ~0;
5787 if (++offset >= PAGE_SIZE && len > 0) {
5788 offset = 0;
5789 page = eb->pages[++i];
5790 WARN_ON(!PageUptodate(page));
5791 kaddr = page_address(page);
5792 }
5793 }
5794 if (len) {
5795 mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5796 kaddr[offset] &= ~mask_to_clear;
5797 }
5798}
5799
5800static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
5801{
5802 unsigned long distance = (src > dst) ? src - dst : dst - src;
5803 return distance < len;
5804}
5805
5806static void copy_pages(struct page *dst_page, struct page *src_page,
5807 unsigned long dst_off, unsigned long src_off,
5808 unsigned long len)
5809{
5810 char *dst_kaddr = page_address(dst_page);
5811 char *src_kaddr;
5812 int must_memmove = 0;
5813
5814 if (dst_page != src_page) {
5815 src_kaddr = page_address(src_page);
5816 } else {
5817 src_kaddr = dst_kaddr;
5818 if (areas_overlap(src_off, dst_off, len))
5819 must_memmove = 1;
5820 }
5821
5822 if (must_memmove)
5823 memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
5824 else
5825 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5826}
5827
5828void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5829 unsigned long src_offset, unsigned long len)
5830{
5831 struct btrfs_fs_info *fs_info = dst->fs_info;
5832 size_t cur;
5833 size_t dst_off_in_page;
5834 size_t src_off_in_page;
5835 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5836 unsigned long dst_i;
5837 unsigned long src_i;
5838
5839 if (src_offset + len > dst->len) {
5840 btrfs_err(fs_info,
5841 "memmove bogus src_offset %lu move len %lu dst len %lu",
5842 src_offset, len, dst->len);
5843 BUG_ON(1);
5844 }
5845 if (dst_offset + len > dst->len) {
5846 btrfs_err(fs_info,
5847 "memmove bogus dst_offset %lu move len %lu dst len %lu",
5848 dst_offset, len, dst->len);
5849 BUG_ON(1);
5850 }
5851
5852 while (len > 0) {
5853 dst_off_in_page = (start_offset + dst_offset) &
5854 (PAGE_SIZE - 1);
5855 src_off_in_page = (start_offset + src_offset) &
5856 (PAGE_SIZE - 1);
5857
5858 dst_i = (start_offset + dst_offset) >> PAGE_SHIFT;
5859 src_i = (start_offset + src_offset) >> PAGE_SHIFT;
5860
5861 cur = min(len, (unsigned long)(PAGE_SIZE -
5862 src_off_in_page));
5863 cur = min_t(unsigned long, cur,
5864 (unsigned long)(PAGE_SIZE - dst_off_in_page));
5865
5866 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5867 dst_off_in_page, src_off_in_page, cur);
5868
5869 src_offset += cur;
5870 dst_offset += cur;
5871 len -= cur;
5872 }
5873}
5874
5875void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5876 unsigned long src_offset, unsigned long len)
5877{
5878 struct btrfs_fs_info *fs_info = dst->fs_info;
5879 size_t cur;
5880 size_t dst_off_in_page;
5881 size_t src_off_in_page;
5882 unsigned long dst_end = dst_offset + len - 1;
5883 unsigned long src_end = src_offset + len - 1;
5884 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5885 unsigned long dst_i;
5886 unsigned long src_i;
5887
5888 if (src_offset + len > dst->len) {
5889 btrfs_err(fs_info,
5890 "memmove bogus src_offset %lu move len %lu len %lu",
5891 src_offset, len, dst->len);
5892 BUG_ON(1);
5893 }
5894 if (dst_offset + len > dst->len) {
5895 btrfs_err(fs_info,
5896 "memmove bogus dst_offset %lu move len %lu len %lu",
5897 dst_offset, len, dst->len);
5898 BUG_ON(1);
5899 }
5900 if (dst_offset < src_offset) {
5901 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
5902 return;
5903 }
5904 while (len > 0) {
5905 dst_i = (start_offset + dst_end) >> PAGE_SHIFT;
5906 src_i = (start_offset + src_end) >> PAGE_SHIFT;
5907
5908 dst_off_in_page = (start_offset + dst_end) &
5909 (PAGE_SIZE - 1);
5910 src_off_in_page = (start_offset + src_end) &
5911 (PAGE_SIZE - 1);
5912
5913 cur = min_t(unsigned long, len, src_off_in_page + 1);
5914 cur = min(cur, dst_off_in_page + 1);
5915 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5916 dst_off_in_page - cur + 1,
5917 src_off_in_page - cur + 1, cur);
5918
5919 dst_end -= cur;
5920 src_end -= cur;
5921 len -= cur;
5922 }
5923}
5924
5925int try_release_extent_buffer(struct page *page)
5926{
5927 struct extent_buffer *eb;
5928
5929 /*
5930 * We need to make sure nobody is attaching this page to an eb right
5931 * now.
5932 */
5933 spin_lock(&page->mapping->private_lock);
5934 if (!PagePrivate(page)) {
5935 spin_unlock(&page->mapping->private_lock);
5936 return 1;
5937 }
5938
5939 eb = (struct extent_buffer *)page->private;
5940 BUG_ON(!eb);
5941
5942 /*
5943 * This is a little awful but should be ok, we need to make sure that
5944 * the eb doesn't disappear out from under us while we're looking at
5945 * this page.
5946 */
5947 spin_lock(&eb->refs_lock);
5948 if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5949 spin_unlock(&eb->refs_lock);
5950 spin_unlock(&page->mapping->private_lock);
5951 return 0;
5952 }
5953 spin_unlock(&page->mapping->private_lock);
5954
5955 /*
5956 * If tree ref isn't set then we know the ref on this eb is a real ref,
5957 * so just return, this page will likely be freed soon anyway.
5958 */
5959 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
5960 spin_unlock(&eb->refs_lock);
5961 return 0;
5962 }
5963
5964 return release_extent_buffer(eb);
5965}