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1#include <linux/bitops.h>
2#include <linux/slab.h>
3#include <linux/bio.h>
4#include <linux/mm.h>
5#include <linux/pagemap.h>
6#include <linux/page-flags.h>
7#include <linux/module.h>
8#include <linux/spinlock.h>
9#include <linux/blkdev.h>
10#include <linux/swap.h>
11#include <linux/writeback.h>
12#include <linux/pagevec.h>
13#include <linux/prefetch.h>
14#include <linux/cleancache.h>
15#include "extent_io.h"
16#include "extent_map.h"
17#include "compat.h"
18#include "ctree.h"
19#include "btrfs_inode.h"
20
21static struct kmem_cache *extent_state_cache;
22static struct kmem_cache *extent_buffer_cache;
23
24static LIST_HEAD(buffers);
25static LIST_HEAD(states);
26
27#define LEAK_DEBUG 0
28#if LEAK_DEBUG
29static DEFINE_SPINLOCK(leak_lock);
30#endif
31
32#define BUFFER_LRU_MAX 64
33
34struct tree_entry {
35 u64 start;
36 u64 end;
37 struct rb_node rb_node;
38};
39
40struct extent_page_data {
41 struct bio *bio;
42 struct extent_io_tree *tree;
43 get_extent_t *get_extent;
44
45 /* tells writepage not to lock the state bits for this range
46 * it still does the unlocking
47 */
48 unsigned int extent_locked:1;
49
50 /* tells the submit_bio code to use a WRITE_SYNC */
51 unsigned int sync_io:1;
52};
53
54int __init extent_io_init(void)
55{
56 extent_state_cache = kmem_cache_create("extent_state",
57 sizeof(struct extent_state), 0,
58 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
59 if (!extent_state_cache)
60 return -ENOMEM;
61
62 extent_buffer_cache = kmem_cache_create("extent_buffers",
63 sizeof(struct extent_buffer), 0,
64 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
65 if (!extent_buffer_cache)
66 goto free_state_cache;
67 return 0;
68
69free_state_cache:
70 kmem_cache_destroy(extent_state_cache);
71 return -ENOMEM;
72}
73
74void extent_io_exit(void)
75{
76 struct extent_state *state;
77 struct extent_buffer *eb;
78
79 while (!list_empty(&states)) {
80 state = list_entry(states.next, struct extent_state, leak_list);
81 printk(KERN_ERR "btrfs state leak: start %llu end %llu "
82 "state %lu in tree %p refs %d\n",
83 (unsigned long long)state->start,
84 (unsigned long long)state->end,
85 state->state, state->tree, atomic_read(&state->refs));
86 list_del(&state->leak_list);
87 kmem_cache_free(extent_state_cache, state);
88
89 }
90
91 while (!list_empty(&buffers)) {
92 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
93 printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
94 "refs %d\n", (unsigned long long)eb->start,
95 eb->len, atomic_read(&eb->refs));
96 list_del(&eb->leak_list);
97 kmem_cache_free(extent_buffer_cache, eb);
98 }
99 if (extent_state_cache)
100 kmem_cache_destroy(extent_state_cache);
101 if (extent_buffer_cache)
102 kmem_cache_destroy(extent_buffer_cache);
103}
104
105void extent_io_tree_init(struct extent_io_tree *tree,
106 struct address_space *mapping)
107{
108 tree->state = RB_ROOT;
109 INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
110 tree->ops = NULL;
111 tree->dirty_bytes = 0;
112 spin_lock_init(&tree->lock);
113 spin_lock_init(&tree->buffer_lock);
114 tree->mapping = mapping;
115}
116
117static struct extent_state *alloc_extent_state(gfp_t mask)
118{
119 struct extent_state *state;
120#if LEAK_DEBUG
121 unsigned long flags;
122#endif
123
124 state = kmem_cache_alloc(extent_state_cache, mask);
125 if (!state)
126 return state;
127 state->state = 0;
128 state->private = 0;
129 state->tree = NULL;
130#if LEAK_DEBUG
131 spin_lock_irqsave(&leak_lock, flags);
132 list_add(&state->leak_list, &states);
133 spin_unlock_irqrestore(&leak_lock, flags);
134#endif
135 atomic_set(&state->refs, 1);
136 init_waitqueue_head(&state->wq);
137 return state;
138}
139
140void free_extent_state(struct extent_state *state)
141{
142 if (!state)
143 return;
144 if (atomic_dec_and_test(&state->refs)) {
145#if LEAK_DEBUG
146 unsigned long flags;
147#endif
148 WARN_ON(state->tree);
149#if LEAK_DEBUG
150 spin_lock_irqsave(&leak_lock, flags);
151 list_del(&state->leak_list);
152 spin_unlock_irqrestore(&leak_lock, flags);
153#endif
154 kmem_cache_free(extent_state_cache, state);
155 }
156}
157
158static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
159 struct rb_node *node)
160{
161 struct rb_node **p = &root->rb_node;
162 struct rb_node *parent = NULL;
163 struct tree_entry *entry;
164
165 while (*p) {
166 parent = *p;
167 entry = rb_entry(parent, struct tree_entry, rb_node);
168
169 if (offset < entry->start)
170 p = &(*p)->rb_left;
171 else if (offset > entry->end)
172 p = &(*p)->rb_right;
173 else
174 return parent;
175 }
176
177 entry = rb_entry(node, struct tree_entry, rb_node);
178 rb_link_node(node, parent, p);
179 rb_insert_color(node, root);
180 return NULL;
181}
182
183static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
184 struct rb_node **prev_ret,
185 struct rb_node **next_ret)
186{
187 struct rb_root *root = &tree->state;
188 struct rb_node *n = root->rb_node;
189 struct rb_node *prev = NULL;
190 struct rb_node *orig_prev = NULL;
191 struct tree_entry *entry;
192 struct tree_entry *prev_entry = NULL;
193
194 while (n) {
195 entry = rb_entry(n, struct tree_entry, rb_node);
196 prev = n;
197 prev_entry = entry;
198
199 if (offset < entry->start)
200 n = n->rb_left;
201 else if (offset > entry->end)
202 n = n->rb_right;
203 else
204 return n;
205 }
206
207 if (prev_ret) {
208 orig_prev = prev;
209 while (prev && offset > prev_entry->end) {
210 prev = rb_next(prev);
211 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
212 }
213 *prev_ret = prev;
214 prev = orig_prev;
215 }
216
217 if (next_ret) {
218 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
219 while (prev && offset < prev_entry->start) {
220 prev = rb_prev(prev);
221 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
222 }
223 *next_ret = prev;
224 }
225 return NULL;
226}
227
228static inline struct rb_node *tree_search(struct extent_io_tree *tree,
229 u64 offset)
230{
231 struct rb_node *prev = NULL;
232 struct rb_node *ret;
233
234 ret = __etree_search(tree, offset, &prev, NULL);
235 if (!ret)
236 return prev;
237 return ret;
238}
239
240static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
241 struct extent_state *other)
242{
243 if (tree->ops && tree->ops->merge_extent_hook)
244 tree->ops->merge_extent_hook(tree->mapping->host, new,
245 other);
246}
247
248/*
249 * utility function to look for merge candidates inside a given range.
250 * Any extents with matching state are merged together into a single
251 * extent in the tree. Extents with EXTENT_IO in their state field
252 * are not merged because the end_io handlers need to be able to do
253 * operations on them without sleeping (or doing allocations/splits).
254 *
255 * This should be called with the tree lock held.
256 */
257static void merge_state(struct extent_io_tree *tree,
258 struct extent_state *state)
259{
260 struct extent_state *other;
261 struct rb_node *other_node;
262
263 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
264 return;
265
266 other_node = rb_prev(&state->rb_node);
267 if (other_node) {
268 other = rb_entry(other_node, struct extent_state, rb_node);
269 if (other->end == state->start - 1 &&
270 other->state == state->state) {
271 merge_cb(tree, state, other);
272 state->start = other->start;
273 other->tree = NULL;
274 rb_erase(&other->rb_node, &tree->state);
275 free_extent_state(other);
276 }
277 }
278 other_node = rb_next(&state->rb_node);
279 if (other_node) {
280 other = rb_entry(other_node, struct extent_state, rb_node);
281 if (other->start == state->end + 1 &&
282 other->state == state->state) {
283 merge_cb(tree, state, other);
284 state->end = other->end;
285 other->tree = NULL;
286 rb_erase(&other->rb_node, &tree->state);
287 free_extent_state(other);
288 }
289 }
290}
291
292static void set_state_cb(struct extent_io_tree *tree,
293 struct extent_state *state, int *bits)
294{
295 if (tree->ops && tree->ops->set_bit_hook)
296 tree->ops->set_bit_hook(tree->mapping->host, state, bits);
297}
298
299static void clear_state_cb(struct extent_io_tree *tree,
300 struct extent_state *state, int *bits)
301{
302 if (tree->ops && tree->ops->clear_bit_hook)
303 tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
304}
305
306static void set_state_bits(struct extent_io_tree *tree,
307 struct extent_state *state, int *bits);
308
309/*
310 * insert an extent_state struct into the tree. 'bits' are set on the
311 * struct before it is inserted.
312 *
313 * This may return -EEXIST if the extent is already there, in which case the
314 * state struct is freed.
315 *
316 * The tree lock is not taken internally. This is a utility function and
317 * probably isn't what you want to call (see set/clear_extent_bit).
318 */
319static int insert_state(struct extent_io_tree *tree,
320 struct extent_state *state, u64 start, u64 end,
321 int *bits)
322{
323 struct rb_node *node;
324
325 if (end < start) {
326 printk(KERN_ERR "btrfs end < start %llu %llu\n",
327 (unsigned long long)end,
328 (unsigned long long)start);
329 WARN_ON(1);
330 }
331 state->start = start;
332 state->end = end;
333
334 set_state_bits(tree, state, bits);
335
336 node = tree_insert(&tree->state, end, &state->rb_node);
337 if (node) {
338 struct extent_state *found;
339 found = rb_entry(node, struct extent_state, rb_node);
340 printk(KERN_ERR "btrfs found node %llu %llu on insert of "
341 "%llu %llu\n", (unsigned long long)found->start,
342 (unsigned long long)found->end,
343 (unsigned long long)start, (unsigned long long)end);
344 return -EEXIST;
345 }
346 state->tree = tree;
347 merge_state(tree, state);
348 return 0;
349}
350
351static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
352 u64 split)
353{
354 if (tree->ops && tree->ops->split_extent_hook)
355 tree->ops->split_extent_hook(tree->mapping->host, orig, split);
356}
357
358/*
359 * split a given extent state struct in two, inserting the preallocated
360 * struct 'prealloc' as the newly created second half. 'split' indicates an
361 * offset inside 'orig' where it should be split.
362 *
363 * Before calling,
364 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
365 * are two extent state structs in the tree:
366 * prealloc: [orig->start, split - 1]
367 * orig: [ split, orig->end ]
368 *
369 * The tree locks are not taken by this function. They need to be held
370 * by the caller.
371 */
372static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
373 struct extent_state *prealloc, u64 split)
374{
375 struct rb_node *node;
376
377 split_cb(tree, orig, split);
378
379 prealloc->start = orig->start;
380 prealloc->end = split - 1;
381 prealloc->state = orig->state;
382 orig->start = split;
383
384 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
385 if (node) {
386 free_extent_state(prealloc);
387 return -EEXIST;
388 }
389 prealloc->tree = tree;
390 return 0;
391}
392
393/*
394 * utility function to clear some bits in an extent state struct.
395 * it will optionally wake up any one waiting on this state (wake == 1), or
396 * forcibly remove the state from the tree (delete == 1).
397 *
398 * If no bits are set on the state struct after clearing things, the
399 * struct is freed and removed from the tree
400 */
401static int clear_state_bit(struct extent_io_tree *tree,
402 struct extent_state *state,
403 int *bits, int wake)
404{
405 int bits_to_clear = *bits & ~EXTENT_CTLBITS;
406 int ret = state->state & bits_to_clear;
407
408 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
409 u64 range = state->end - state->start + 1;
410 WARN_ON(range > tree->dirty_bytes);
411 tree->dirty_bytes -= range;
412 }
413 clear_state_cb(tree, state, bits);
414 state->state &= ~bits_to_clear;
415 if (wake)
416 wake_up(&state->wq);
417 if (state->state == 0) {
418 if (state->tree) {
419 rb_erase(&state->rb_node, &tree->state);
420 state->tree = NULL;
421 free_extent_state(state);
422 } else {
423 WARN_ON(1);
424 }
425 } else {
426 merge_state(tree, state);
427 }
428 return ret;
429}
430
431static struct extent_state *
432alloc_extent_state_atomic(struct extent_state *prealloc)
433{
434 if (!prealloc)
435 prealloc = alloc_extent_state(GFP_ATOMIC);
436
437 return prealloc;
438}
439
440/*
441 * clear some bits on a range in the tree. This may require splitting
442 * or inserting elements in the tree, so the gfp mask is used to
443 * indicate which allocations or sleeping are allowed.
444 *
445 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
446 * the given range from the tree regardless of state (ie for truncate).
447 *
448 * the range [start, end] is inclusive.
449 *
450 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
451 * bits were already set, or zero if none of the bits were already set.
452 */
453int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
454 int bits, int wake, int delete,
455 struct extent_state **cached_state,
456 gfp_t mask)
457{
458 struct extent_state *state;
459 struct extent_state *cached;
460 struct extent_state *prealloc = NULL;
461 struct rb_node *next_node;
462 struct rb_node *node;
463 u64 last_end;
464 int err;
465 int set = 0;
466 int clear = 0;
467
468 if (delete)
469 bits |= ~EXTENT_CTLBITS;
470 bits |= EXTENT_FIRST_DELALLOC;
471
472 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
473 clear = 1;
474again:
475 if (!prealloc && (mask & __GFP_WAIT)) {
476 prealloc = alloc_extent_state(mask);
477 if (!prealloc)
478 return -ENOMEM;
479 }
480
481 spin_lock(&tree->lock);
482 if (cached_state) {
483 cached = *cached_state;
484
485 if (clear) {
486 *cached_state = NULL;
487 cached_state = NULL;
488 }
489
490 if (cached && cached->tree && cached->start <= start &&
491 cached->end > start) {
492 if (clear)
493 atomic_dec(&cached->refs);
494 state = cached;
495 goto hit_next;
496 }
497 if (clear)
498 free_extent_state(cached);
499 }
500 /*
501 * this search will find the extents that end after
502 * our range starts
503 */
504 node = tree_search(tree, start);
505 if (!node)
506 goto out;
507 state = rb_entry(node, struct extent_state, rb_node);
508hit_next:
509 if (state->start > end)
510 goto out;
511 WARN_ON(state->end < start);
512 last_end = state->end;
513
514 /*
515 * | ---- desired range ---- |
516 * | state | or
517 * | ------------- state -------------- |
518 *
519 * We need to split the extent we found, and may flip
520 * bits on second half.
521 *
522 * If the extent we found extends past our range, we
523 * just split and search again. It'll get split again
524 * the next time though.
525 *
526 * If the extent we found is inside our range, we clear
527 * the desired bit on it.
528 */
529
530 if (state->start < start) {
531 prealloc = alloc_extent_state_atomic(prealloc);
532 BUG_ON(!prealloc);
533 err = split_state(tree, state, prealloc, start);
534 BUG_ON(err == -EEXIST);
535 prealloc = NULL;
536 if (err)
537 goto out;
538 if (state->end <= end) {
539 set |= clear_state_bit(tree, state, &bits, wake);
540 if (last_end == (u64)-1)
541 goto out;
542 start = last_end + 1;
543 }
544 goto search_again;
545 }
546 /*
547 * | ---- desired range ---- |
548 * | state |
549 * We need to split the extent, and clear the bit
550 * on the first half
551 */
552 if (state->start <= end && state->end > end) {
553 prealloc = alloc_extent_state_atomic(prealloc);
554 BUG_ON(!prealloc);
555 err = split_state(tree, state, prealloc, end + 1);
556 BUG_ON(err == -EEXIST);
557 if (wake)
558 wake_up(&state->wq);
559
560 set |= clear_state_bit(tree, prealloc, &bits, wake);
561
562 prealloc = NULL;
563 goto out;
564 }
565
566 if (state->end < end && prealloc && !need_resched())
567 next_node = rb_next(&state->rb_node);
568 else
569 next_node = NULL;
570
571 set |= clear_state_bit(tree, state, &bits, wake);
572 if (last_end == (u64)-1)
573 goto out;
574 start = last_end + 1;
575 if (start <= end && next_node) {
576 state = rb_entry(next_node, struct extent_state,
577 rb_node);
578 if (state->start == start)
579 goto hit_next;
580 }
581 goto search_again;
582
583out:
584 spin_unlock(&tree->lock);
585 if (prealloc)
586 free_extent_state(prealloc);
587
588 return set;
589
590search_again:
591 if (start > end)
592 goto out;
593 spin_unlock(&tree->lock);
594 if (mask & __GFP_WAIT)
595 cond_resched();
596 goto again;
597}
598
599static int wait_on_state(struct extent_io_tree *tree,
600 struct extent_state *state)
601 __releases(tree->lock)
602 __acquires(tree->lock)
603{
604 DEFINE_WAIT(wait);
605 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
606 spin_unlock(&tree->lock);
607 schedule();
608 spin_lock(&tree->lock);
609 finish_wait(&state->wq, &wait);
610 return 0;
611}
612
613/*
614 * waits for one or more bits to clear on a range in the state tree.
615 * The range [start, end] is inclusive.
616 * The tree lock is taken by this function
617 */
618int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
619{
620 struct extent_state *state;
621 struct rb_node *node;
622
623 spin_lock(&tree->lock);
624again:
625 while (1) {
626 /*
627 * this search will find all the extents that end after
628 * our range starts
629 */
630 node = tree_search(tree, start);
631 if (!node)
632 break;
633
634 state = rb_entry(node, struct extent_state, rb_node);
635
636 if (state->start > end)
637 goto out;
638
639 if (state->state & bits) {
640 start = state->start;
641 atomic_inc(&state->refs);
642 wait_on_state(tree, state);
643 free_extent_state(state);
644 goto again;
645 }
646 start = state->end + 1;
647
648 if (start > end)
649 break;
650
651 cond_resched_lock(&tree->lock);
652 }
653out:
654 spin_unlock(&tree->lock);
655 return 0;
656}
657
658static void set_state_bits(struct extent_io_tree *tree,
659 struct extent_state *state,
660 int *bits)
661{
662 int bits_to_set = *bits & ~EXTENT_CTLBITS;
663
664 set_state_cb(tree, state, bits);
665 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
666 u64 range = state->end - state->start + 1;
667 tree->dirty_bytes += range;
668 }
669 state->state |= bits_to_set;
670}
671
672static void cache_state(struct extent_state *state,
673 struct extent_state **cached_ptr)
674{
675 if (cached_ptr && !(*cached_ptr)) {
676 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
677 *cached_ptr = state;
678 atomic_inc(&state->refs);
679 }
680 }
681}
682
683static void uncache_state(struct extent_state **cached_ptr)
684{
685 if (cached_ptr && (*cached_ptr)) {
686 struct extent_state *state = *cached_ptr;
687 *cached_ptr = NULL;
688 free_extent_state(state);
689 }
690}
691
692/*
693 * set some bits on a range in the tree. This may require allocations or
694 * sleeping, so the gfp mask is used to indicate what is allowed.
695 *
696 * If any of the exclusive bits are set, this will fail with -EEXIST if some
697 * part of the range already has the desired bits set. The start of the
698 * existing range is returned in failed_start in this case.
699 *
700 * [start, end] is inclusive This takes the tree lock.
701 */
702
703int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
704 int bits, int exclusive_bits, u64 *failed_start,
705 struct extent_state **cached_state, gfp_t mask)
706{
707 struct extent_state *state;
708 struct extent_state *prealloc = NULL;
709 struct rb_node *node;
710 int err = 0;
711 u64 last_start;
712 u64 last_end;
713
714 bits |= EXTENT_FIRST_DELALLOC;
715again:
716 if (!prealloc && (mask & __GFP_WAIT)) {
717 prealloc = alloc_extent_state(mask);
718 BUG_ON(!prealloc);
719 }
720
721 spin_lock(&tree->lock);
722 if (cached_state && *cached_state) {
723 state = *cached_state;
724 if (state->start <= start && state->end > start &&
725 state->tree) {
726 node = &state->rb_node;
727 goto hit_next;
728 }
729 }
730 /*
731 * this search will find all the extents that end after
732 * our range starts.
733 */
734 node = tree_search(tree, start);
735 if (!node) {
736 prealloc = alloc_extent_state_atomic(prealloc);
737 BUG_ON(!prealloc);
738 err = insert_state(tree, prealloc, start, end, &bits);
739 prealloc = NULL;
740 BUG_ON(err == -EEXIST);
741 goto out;
742 }
743 state = rb_entry(node, struct extent_state, rb_node);
744hit_next:
745 last_start = state->start;
746 last_end = state->end;
747
748 /*
749 * | ---- desired range ---- |
750 * | state |
751 *
752 * Just lock what we found and keep going
753 */
754 if (state->start == start && state->end <= end) {
755 struct rb_node *next_node;
756 if (state->state & exclusive_bits) {
757 *failed_start = state->start;
758 err = -EEXIST;
759 goto out;
760 }
761
762 set_state_bits(tree, state, &bits);
763
764 cache_state(state, cached_state);
765 merge_state(tree, state);
766 if (last_end == (u64)-1)
767 goto out;
768
769 start = last_end + 1;
770 next_node = rb_next(&state->rb_node);
771 if (next_node && start < end && prealloc && !need_resched()) {
772 state = rb_entry(next_node, struct extent_state,
773 rb_node);
774 if (state->start == start)
775 goto hit_next;
776 }
777 goto search_again;
778 }
779
780 /*
781 * | ---- desired range ---- |
782 * | state |
783 * or
784 * | ------------- state -------------- |
785 *
786 * We need to split the extent we found, and may flip bits on
787 * second half.
788 *
789 * If the extent we found extends past our
790 * range, we just split and search again. It'll get split
791 * again the next time though.
792 *
793 * If the extent we found is inside our range, we set the
794 * desired bit on it.
795 */
796 if (state->start < start) {
797 if (state->state & exclusive_bits) {
798 *failed_start = start;
799 err = -EEXIST;
800 goto out;
801 }
802
803 prealloc = alloc_extent_state_atomic(prealloc);
804 BUG_ON(!prealloc);
805 err = split_state(tree, state, prealloc, start);
806 BUG_ON(err == -EEXIST);
807 prealloc = NULL;
808 if (err)
809 goto out;
810 if (state->end <= end) {
811 set_state_bits(tree, state, &bits);
812 cache_state(state, cached_state);
813 merge_state(tree, state);
814 if (last_end == (u64)-1)
815 goto out;
816 start = last_end + 1;
817 }
818 goto search_again;
819 }
820 /*
821 * | ---- desired range ---- |
822 * | state | or | state |
823 *
824 * There's a hole, we need to insert something in it and
825 * ignore the extent we found.
826 */
827 if (state->start > start) {
828 u64 this_end;
829 if (end < last_start)
830 this_end = end;
831 else
832 this_end = last_start - 1;
833
834 prealloc = alloc_extent_state_atomic(prealloc);
835 BUG_ON(!prealloc);
836
837 /*
838 * Avoid to free 'prealloc' if it can be merged with
839 * the later extent.
840 */
841 err = insert_state(tree, prealloc, start, this_end,
842 &bits);
843 BUG_ON(err == -EEXIST);
844 if (err) {
845 free_extent_state(prealloc);
846 prealloc = NULL;
847 goto out;
848 }
849 cache_state(prealloc, cached_state);
850 prealloc = NULL;
851 start = this_end + 1;
852 goto search_again;
853 }
854 /*
855 * | ---- desired range ---- |
856 * | state |
857 * We need to split the extent, and set the bit
858 * on the first half
859 */
860 if (state->start <= end && state->end > end) {
861 if (state->state & exclusive_bits) {
862 *failed_start = start;
863 err = -EEXIST;
864 goto out;
865 }
866
867 prealloc = alloc_extent_state_atomic(prealloc);
868 BUG_ON(!prealloc);
869 err = split_state(tree, state, prealloc, end + 1);
870 BUG_ON(err == -EEXIST);
871
872 set_state_bits(tree, prealloc, &bits);
873 cache_state(prealloc, cached_state);
874 merge_state(tree, prealloc);
875 prealloc = NULL;
876 goto out;
877 }
878
879 goto search_again;
880
881out:
882 spin_unlock(&tree->lock);
883 if (prealloc)
884 free_extent_state(prealloc);
885
886 return err;
887
888search_again:
889 if (start > end)
890 goto out;
891 spin_unlock(&tree->lock);
892 if (mask & __GFP_WAIT)
893 cond_resched();
894 goto again;
895}
896
897/* wrappers around set/clear extent bit */
898int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
899 gfp_t mask)
900{
901 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
902 NULL, mask);
903}
904
905int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
906 int bits, gfp_t mask)
907{
908 return set_extent_bit(tree, start, end, bits, 0, NULL,
909 NULL, mask);
910}
911
912int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
913 int bits, gfp_t mask)
914{
915 return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
916}
917
918int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
919 struct extent_state **cached_state, gfp_t mask)
920{
921 return set_extent_bit(tree, start, end,
922 EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
923 0, NULL, cached_state, mask);
924}
925
926int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
927 gfp_t mask)
928{
929 return clear_extent_bit(tree, start, end,
930 EXTENT_DIRTY | EXTENT_DELALLOC |
931 EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
932}
933
934int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
935 gfp_t mask)
936{
937 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
938 NULL, mask);
939}
940
941int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
942 struct extent_state **cached_state, gfp_t mask)
943{
944 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0,
945 NULL, cached_state, mask);
946}
947
948static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
949 u64 end, struct extent_state **cached_state,
950 gfp_t mask)
951{
952 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
953 cached_state, mask);
954}
955
956/*
957 * either insert or lock state struct between start and end use mask to tell
958 * us if waiting is desired.
959 */
960int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
961 int bits, struct extent_state **cached_state, gfp_t mask)
962{
963 int err;
964 u64 failed_start;
965 while (1) {
966 err = set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
967 EXTENT_LOCKED, &failed_start,
968 cached_state, mask);
969 if (err == -EEXIST && (mask & __GFP_WAIT)) {
970 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
971 start = failed_start;
972 } else {
973 break;
974 }
975 WARN_ON(start > end);
976 }
977 return err;
978}
979
980int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
981{
982 return lock_extent_bits(tree, start, end, 0, NULL, mask);
983}
984
985int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
986 gfp_t mask)
987{
988 int err;
989 u64 failed_start;
990
991 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
992 &failed_start, NULL, mask);
993 if (err == -EEXIST) {
994 if (failed_start > start)
995 clear_extent_bit(tree, start, failed_start - 1,
996 EXTENT_LOCKED, 1, 0, NULL, mask);
997 return 0;
998 }
999 return 1;
1000}
1001
1002int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
1003 struct extent_state **cached, gfp_t mask)
1004{
1005 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
1006 mask);
1007}
1008
1009int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
1010{
1011 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1012 mask);
1013}
1014
1015/*
1016 * helper function to set both pages and extents in the tree writeback
1017 */
1018static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1019{
1020 unsigned long index = start >> PAGE_CACHE_SHIFT;
1021 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1022 struct page *page;
1023
1024 while (index <= end_index) {
1025 page = find_get_page(tree->mapping, index);
1026 BUG_ON(!page);
1027 set_page_writeback(page);
1028 page_cache_release(page);
1029 index++;
1030 }
1031 return 0;
1032}
1033
1034/* find the first state struct with 'bits' set after 'start', and
1035 * return it. tree->lock must be held. NULL will returned if
1036 * nothing was found after 'start'
1037 */
1038struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
1039 u64 start, int bits)
1040{
1041 struct rb_node *node;
1042 struct extent_state *state;
1043
1044 /*
1045 * this search will find all the extents that end after
1046 * our range starts.
1047 */
1048 node = tree_search(tree, start);
1049 if (!node)
1050 goto out;
1051
1052 while (1) {
1053 state = rb_entry(node, struct extent_state, rb_node);
1054 if (state->end >= start && (state->state & bits))
1055 return state;
1056
1057 node = rb_next(node);
1058 if (!node)
1059 break;
1060 }
1061out:
1062 return NULL;
1063}
1064
1065/*
1066 * find the first offset in the io tree with 'bits' set. zero is
1067 * returned if we find something, and *start_ret and *end_ret are
1068 * set to reflect the state struct that was found.
1069 *
1070 * If nothing was found, 1 is returned, < 0 on error
1071 */
1072int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1073 u64 *start_ret, u64 *end_ret, int bits)
1074{
1075 struct extent_state *state;
1076 int ret = 1;
1077
1078 spin_lock(&tree->lock);
1079 state = find_first_extent_bit_state(tree, start, bits);
1080 if (state) {
1081 *start_ret = state->start;
1082 *end_ret = state->end;
1083 ret = 0;
1084 }
1085 spin_unlock(&tree->lock);
1086 return ret;
1087}
1088
1089/*
1090 * find a contiguous range of bytes in the file marked as delalloc, not
1091 * more than 'max_bytes'. start and end are used to return the range,
1092 *
1093 * 1 is returned if we find something, 0 if nothing was in the tree
1094 */
1095static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1096 u64 *start, u64 *end, u64 max_bytes,
1097 struct extent_state **cached_state)
1098{
1099 struct rb_node *node;
1100 struct extent_state *state;
1101 u64 cur_start = *start;
1102 u64 found = 0;
1103 u64 total_bytes = 0;
1104
1105 spin_lock(&tree->lock);
1106
1107 /*
1108 * this search will find all the extents that end after
1109 * our range starts.
1110 */
1111 node = tree_search(tree, cur_start);
1112 if (!node) {
1113 if (!found)
1114 *end = (u64)-1;
1115 goto out;
1116 }
1117
1118 while (1) {
1119 state = rb_entry(node, struct extent_state, rb_node);
1120 if (found && (state->start != cur_start ||
1121 (state->state & EXTENT_BOUNDARY))) {
1122 goto out;
1123 }
1124 if (!(state->state & EXTENT_DELALLOC)) {
1125 if (!found)
1126 *end = state->end;
1127 goto out;
1128 }
1129 if (!found) {
1130 *start = state->start;
1131 *cached_state = state;
1132 atomic_inc(&state->refs);
1133 }
1134 found++;
1135 *end = state->end;
1136 cur_start = state->end + 1;
1137 node = rb_next(node);
1138 if (!node)
1139 break;
1140 total_bytes += state->end - state->start + 1;
1141 if (total_bytes >= max_bytes)
1142 break;
1143 }
1144out:
1145 spin_unlock(&tree->lock);
1146 return found;
1147}
1148
1149static noinline int __unlock_for_delalloc(struct inode *inode,
1150 struct page *locked_page,
1151 u64 start, u64 end)
1152{
1153 int ret;
1154 struct page *pages[16];
1155 unsigned long index = start >> PAGE_CACHE_SHIFT;
1156 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1157 unsigned long nr_pages = end_index - index + 1;
1158 int i;
1159
1160 if (index == locked_page->index && end_index == index)
1161 return 0;
1162
1163 while (nr_pages > 0) {
1164 ret = find_get_pages_contig(inode->i_mapping, index,
1165 min_t(unsigned long, nr_pages,
1166 ARRAY_SIZE(pages)), pages);
1167 for (i = 0; i < ret; i++) {
1168 if (pages[i] != locked_page)
1169 unlock_page(pages[i]);
1170 page_cache_release(pages[i]);
1171 }
1172 nr_pages -= ret;
1173 index += ret;
1174 cond_resched();
1175 }
1176 return 0;
1177}
1178
1179static noinline int lock_delalloc_pages(struct inode *inode,
1180 struct page *locked_page,
1181 u64 delalloc_start,
1182 u64 delalloc_end)
1183{
1184 unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
1185 unsigned long start_index = index;
1186 unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
1187 unsigned long pages_locked = 0;
1188 struct page *pages[16];
1189 unsigned long nrpages;
1190 int ret;
1191 int i;
1192
1193 /* the caller is responsible for locking the start index */
1194 if (index == locked_page->index && index == end_index)
1195 return 0;
1196
1197 /* skip the page at the start index */
1198 nrpages = end_index - index + 1;
1199 while (nrpages > 0) {
1200 ret = find_get_pages_contig(inode->i_mapping, index,
1201 min_t(unsigned long,
1202 nrpages, ARRAY_SIZE(pages)), pages);
1203 if (ret == 0) {
1204 ret = -EAGAIN;
1205 goto done;
1206 }
1207 /* now we have an array of pages, lock them all */
1208 for (i = 0; i < ret; i++) {
1209 /*
1210 * the caller is taking responsibility for
1211 * locked_page
1212 */
1213 if (pages[i] != locked_page) {
1214 lock_page(pages[i]);
1215 if (!PageDirty(pages[i]) ||
1216 pages[i]->mapping != inode->i_mapping) {
1217 ret = -EAGAIN;
1218 unlock_page(pages[i]);
1219 page_cache_release(pages[i]);
1220 goto done;
1221 }
1222 }
1223 page_cache_release(pages[i]);
1224 pages_locked++;
1225 }
1226 nrpages -= ret;
1227 index += ret;
1228 cond_resched();
1229 }
1230 ret = 0;
1231done:
1232 if (ret && pages_locked) {
1233 __unlock_for_delalloc(inode, locked_page,
1234 delalloc_start,
1235 ((u64)(start_index + pages_locked - 1)) <<
1236 PAGE_CACHE_SHIFT);
1237 }
1238 return ret;
1239}
1240
1241/*
1242 * find a contiguous range of bytes in the file marked as delalloc, not
1243 * more than 'max_bytes'. start and end are used to return the range,
1244 *
1245 * 1 is returned if we find something, 0 if nothing was in the tree
1246 */
1247static noinline u64 find_lock_delalloc_range(struct inode *inode,
1248 struct extent_io_tree *tree,
1249 struct page *locked_page,
1250 u64 *start, u64 *end,
1251 u64 max_bytes)
1252{
1253 u64 delalloc_start;
1254 u64 delalloc_end;
1255 u64 found;
1256 struct extent_state *cached_state = NULL;
1257 int ret;
1258 int loops = 0;
1259
1260again:
1261 /* step one, find a bunch of delalloc bytes starting at start */
1262 delalloc_start = *start;
1263 delalloc_end = 0;
1264 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1265 max_bytes, &cached_state);
1266 if (!found || delalloc_end <= *start) {
1267 *start = delalloc_start;
1268 *end = delalloc_end;
1269 free_extent_state(cached_state);
1270 return found;
1271 }
1272
1273 /*
1274 * start comes from the offset of locked_page. We have to lock
1275 * pages in order, so we can't process delalloc bytes before
1276 * locked_page
1277 */
1278 if (delalloc_start < *start)
1279 delalloc_start = *start;
1280
1281 /*
1282 * make sure to limit the number of pages we try to lock down
1283 * if we're looping.
1284 */
1285 if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1286 delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
1287
1288 /* step two, lock all the pages after the page that has start */
1289 ret = lock_delalloc_pages(inode, locked_page,
1290 delalloc_start, delalloc_end);
1291 if (ret == -EAGAIN) {
1292 /* some of the pages are gone, lets avoid looping by
1293 * shortening the size of the delalloc range we're searching
1294 */
1295 free_extent_state(cached_state);
1296 if (!loops) {
1297 unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
1298 max_bytes = PAGE_CACHE_SIZE - offset;
1299 loops = 1;
1300 goto again;
1301 } else {
1302 found = 0;
1303 goto out_failed;
1304 }
1305 }
1306 BUG_ON(ret);
1307
1308 /* step three, lock the state bits for the whole range */
1309 lock_extent_bits(tree, delalloc_start, delalloc_end,
1310 0, &cached_state, GFP_NOFS);
1311
1312 /* then test to make sure it is all still delalloc */
1313 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1314 EXTENT_DELALLOC, 1, cached_state);
1315 if (!ret) {
1316 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1317 &cached_state, GFP_NOFS);
1318 __unlock_for_delalloc(inode, locked_page,
1319 delalloc_start, delalloc_end);
1320 cond_resched();
1321 goto again;
1322 }
1323 free_extent_state(cached_state);
1324 *start = delalloc_start;
1325 *end = delalloc_end;
1326out_failed:
1327 return found;
1328}
1329
1330int extent_clear_unlock_delalloc(struct inode *inode,
1331 struct extent_io_tree *tree,
1332 u64 start, u64 end, struct page *locked_page,
1333 unsigned long op)
1334{
1335 int ret;
1336 struct page *pages[16];
1337 unsigned long index = start >> PAGE_CACHE_SHIFT;
1338 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1339 unsigned long nr_pages = end_index - index + 1;
1340 int i;
1341 int clear_bits = 0;
1342
1343 if (op & EXTENT_CLEAR_UNLOCK)
1344 clear_bits |= EXTENT_LOCKED;
1345 if (op & EXTENT_CLEAR_DIRTY)
1346 clear_bits |= EXTENT_DIRTY;
1347
1348 if (op & EXTENT_CLEAR_DELALLOC)
1349 clear_bits |= EXTENT_DELALLOC;
1350
1351 clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1352 if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
1353 EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
1354 EXTENT_SET_PRIVATE2)))
1355 return 0;
1356
1357 while (nr_pages > 0) {
1358 ret = find_get_pages_contig(inode->i_mapping, index,
1359 min_t(unsigned long,
1360 nr_pages, ARRAY_SIZE(pages)), pages);
1361 for (i = 0; i < ret; i++) {
1362
1363 if (op & EXTENT_SET_PRIVATE2)
1364 SetPagePrivate2(pages[i]);
1365
1366 if (pages[i] == locked_page) {
1367 page_cache_release(pages[i]);
1368 continue;
1369 }
1370 if (op & EXTENT_CLEAR_DIRTY)
1371 clear_page_dirty_for_io(pages[i]);
1372 if (op & EXTENT_SET_WRITEBACK)
1373 set_page_writeback(pages[i]);
1374 if (op & EXTENT_END_WRITEBACK)
1375 end_page_writeback(pages[i]);
1376 if (op & EXTENT_CLEAR_UNLOCK_PAGE)
1377 unlock_page(pages[i]);
1378 page_cache_release(pages[i]);
1379 }
1380 nr_pages -= ret;
1381 index += ret;
1382 cond_resched();
1383 }
1384 return 0;
1385}
1386
1387/*
1388 * count the number of bytes in the tree that have a given bit(s)
1389 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1390 * cached. The total number found is returned.
1391 */
1392u64 count_range_bits(struct extent_io_tree *tree,
1393 u64 *start, u64 search_end, u64 max_bytes,
1394 unsigned long bits, int contig)
1395{
1396 struct rb_node *node;
1397 struct extent_state *state;
1398 u64 cur_start = *start;
1399 u64 total_bytes = 0;
1400 u64 last = 0;
1401 int found = 0;
1402
1403 if (search_end <= cur_start) {
1404 WARN_ON(1);
1405 return 0;
1406 }
1407
1408 spin_lock(&tree->lock);
1409 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1410 total_bytes = tree->dirty_bytes;
1411 goto out;
1412 }
1413 /*
1414 * this search will find all the extents that end after
1415 * our range starts.
1416 */
1417 node = tree_search(tree, cur_start);
1418 if (!node)
1419 goto out;
1420
1421 while (1) {
1422 state = rb_entry(node, struct extent_state, rb_node);
1423 if (state->start > search_end)
1424 break;
1425 if (contig && found && state->start > last + 1)
1426 break;
1427 if (state->end >= cur_start && (state->state & bits) == bits) {
1428 total_bytes += min(search_end, state->end) + 1 -
1429 max(cur_start, state->start);
1430 if (total_bytes >= max_bytes)
1431 break;
1432 if (!found) {
1433 *start = max(cur_start, state->start);
1434 found = 1;
1435 }
1436 last = state->end;
1437 } else if (contig && found) {
1438 break;
1439 }
1440 node = rb_next(node);
1441 if (!node)
1442 break;
1443 }
1444out:
1445 spin_unlock(&tree->lock);
1446 return total_bytes;
1447}
1448
1449/*
1450 * set the private field for a given byte offset in the tree. If there isn't
1451 * an extent_state there already, this does nothing.
1452 */
1453int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1454{
1455 struct rb_node *node;
1456 struct extent_state *state;
1457 int ret = 0;
1458
1459 spin_lock(&tree->lock);
1460 /*
1461 * this search will find all the extents that end after
1462 * our range starts.
1463 */
1464 node = tree_search(tree, start);
1465 if (!node) {
1466 ret = -ENOENT;
1467 goto out;
1468 }
1469 state = rb_entry(node, struct extent_state, rb_node);
1470 if (state->start != start) {
1471 ret = -ENOENT;
1472 goto out;
1473 }
1474 state->private = private;
1475out:
1476 spin_unlock(&tree->lock);
1477 return ret;
1478}
1479
1480int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1481{
1482 struct rb_node *node;
1483 struct extent_state *state;
1484 int ret = 0;
1485
1486 spin_lock(&tree->lock);
1487 /*
1488 * this search will find all the extents that end after
1489 * our range starts.
1490 */
1491 node = tree_search(tree, start);
1492 if (!node) {
1493 ret = -ENOENT;
1494 goto out;
1495 }
1496 state = rb_entry(node, struct extent_state, rb_node);
1497 if (state->start != start) {
1498 ret = -ENOENT;
1499 goto out;
1500 }
1501 *private = state->private;
1502out:
1503 spin_unlock(&tree->lock);
1504 return ret;
1505}
1506
1507/*
1508 * searches a range in the state tree for a given mask.
1509 * If 'filled' == 1, this returns 1 only if every extent in the tree
1510 * has the bits set. Otherwise, 1 is returned if any bit in the
1511 * range is found set.
1512 */
1513int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1514 int bits, int filled, struct extent_state *cached)
1515{
1516 struct extent_state *state = NULL;
1517 struct rb_node *node;
1518 int bitset = 0;
1519
1520 spin_lock(&tree->lock);
1521 if (cached && cached->tree && cached->start <= start &&
1522 cached->end > start)
1523 node = &cached->rb_node;
1524 else
1525 node = tree_search(tree, start);
1526 while (node && start <= end) {
1527 state = rb_entry(node, struct extent_state, rb_node);
1528
1529 if (filled && state->start > start) {
1530 bitset = 0;
1531 break;
1532 }
1533
1534 if (state->start > end)
1535 break;
1536
1537 if (state->state & bits) {
1538 bitset = 1;
1539 if (!filled)
1540 break;
1541 } else if (filled) {
1542 bitset = 0;
1543 break;
1544 }
1545
1546 if (state->end == (u64)-1)
1547 break;
1548
1549 start = state->end + 1;
1550 if (start > end)
1551 break;
1552 node = rb_next(node);
1553 if (!node) {
1554 if (filled)
1555 bitset = 0;
1556 break;
1557 }
1558 }
1559 spin_unlock(&tree->lock);
1560 return bitset;
1561}
1562
1563/*
1564 * helper function to set a given page up to date if all the
1565 * extents in the tree for that page are up to date
1566 */
1567static int check_page_uptodate(struct extent_io_tree *tree,
1568 struct page *page)
1569{
1570 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1571 u64 end = start + PAGE_CACHE_SIZE - 1;
1572 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1573 SetPageUptodate(page);
1574 return 0;
1575}
1576
1577/*
1578 * helper function to unlock a page if all the extents in the tree
1579 * for that page are unlocked
1580 */
1581static int check_page_locked(struct extent_io_tree *tree,
1582 struct page *page)
1583{
1584 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1585 u64 end = start + PAGE_CACHE_SIZE - 1;
1586 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
1587 unlock_page(page);
1588 return 0;
1589}
1590
1591/*
1592 * helper function to end page writeback if all the extents
1593 * in the tree for that page are done with writeback
1594 */
1595static int check_page_writeback(struct extent_io_tree *tree,
1596 struct page *page)
1597{
1598 end_page_writeback(page);
1599 return 0;
1600}
1601
1602/* lots and lots of room for performance fixes in the end_bio funcs */
1603
1604/*
1605 * after a writepage IO is done, we need to:
1606 * clear the uptodate bits on error
1607 * clear the writeback bits in the extent tree for this IO
1608 * end_page_writeback if the page has no more pending IO
1609 *
1610 * Scheduling is not allowed, so the extent state tree is expected
1611 * to have one and only one object corresponding to this IO.
1612 */
1613static void end_bio_extent_writepage(struct bio *bio, int err)
1614{
1615 int uptodate = err == 0;
1616 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1617 struct extent_io_tree *tree;
1618 u64 start;
1619 u64 end;
1620 int whole_page;
1621 int ret;
1622
1623 do {
1624 struct page *page = bvec->bv_page;
1625 tree = &BTRFS_I(page->mapping->host)->io_tree;
1626
1627 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1628 bvec->bv_offset;
1629 end = start + bvec->bv_len - 1;
1630
1631 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1632 whole_page = 1;
1633 else
1634 whole_page = 0;
1635
1636 if (--bvec >= bio->bi_io_vec)
1637 prefetchw(&bvec->bv_page->flags);
1638 if (tree->ops && tree->ops->writepage_end_io_hook) {
1639 ret = tree->ops->writepage_end_io_hook(page, start,
1640 end, NULL, uptodate);
1641 if (ret)
1642 uptodate = 0;
1643 }
1644
1645 if (!uptodate && tree->ops &&
1646 tree->ops->writepage_io_failed_hook) {
1647 ret = tree->ops->writepage_io_failed_hook(bio, page,
1648 start, end, NULL);
1649 if (ret == 0) {
1650 uptodate = (err == 0);
1651 continue;
1652 }
1653 }
1654
1655 if (!uptodate) {
1656 clear_extent_uptodate(tree, start, end, NULL, GFP_NOFS);
1657 ClearPageUptodate(page);
1658 SetPageError(page);
1659 }
1660
1661 if (whole_page)
1662 end_page_writeback(page);
1663 else
1664 check_page_writeback(tree, page);
1665 } while (bvec >= bio->bi_io_vec);
1666
1667 bio_put(bio);
1668}
1669
1670/*
1671 * after a readpage IO is done, we need to:
1672 * clear the uptodate bits on error
1673 * set the uptodate bits if things worked
1674 * set the page up to date if all extents in the tree are uptodate
1675 * clear the lock bit in the extent tree
1676 * unlock the page if there are no other extents locked for it
1677 *
1678 * Scheduling is not allowed, so the extent state tree is expected
1679 * to have one and only one object corresponding to this IO.
1680 */
1681static void end_bio_extent_readpage(struct bio *bio, int err)
1682{
1683 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1684 struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
1685 struct bio_vec *bvec = bio->bi_io_vec;
1686 struct extent_io_tree *tree;
1687 u64 start;
1688 u64 end;
1689 int whole_page;
1690 int ret;
1691
1692 if (err)
1693 uptodate = 0;
1694
1695 do {
1696 struct page *page = bvec->bv_page;
1697 struct extent_state *cached = NULL;
1698 struct extent_state *state;
1699
1700 tree = &BTRFS_I(page->mapping->host)->io_tree;
1701
1702 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1703 bvec->bv_offset;
1704 end = start + bvec->bv_len - 1;
1705
1706 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1707 whole_page = 1;
1708 else
1709 whole_page = 0;
1710
1711 if (++bvec <= bvec_end)
1712 prefetchw(&bvec->bv_page->flags);
1713
1714 spin_lock(&tree->lock);
1715 state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
1716 if (state && state->start == start) {
1717 /*
1718 * take a reference on the state, unlock will drop
1719 * the ref
1720 */
1721 cache_state(state, &cached);
1722 }
1723 spin_unlock(&tree->lock);
1724
1725 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1726 ret = tree->ops->readpage_end_io_hook(page, start, end,
1727 state);
1728 if (ret)
1729 uptodate = 0;
1730 }
1731 if (!uptodate && tree->ops &&
1732 tree->ops->readpage_io_failed_hook) {
1733 ret = tree->ops->readpage_io_failed_hook(bio, page,
1734 start, end, NULL);
1735 if (ret == 0) {
1736 uptodate =
1737 test_bit(BIO_UPTODATE, &bio->bi_flags);
1738 if (err)
1739 uptodate = 0;
1740 uncache_state(&cached);
1741 continue;
1742 }
1743 }
1744
1745 if (uptodate) {
1746 set_extent_uptodate(tree, start, end, &cached,
1747 GFP_ATOMIC);
1748 }
1749 unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
1750
1751 if (whole_page) {
1752 if (uptodate) {
1753 SetPageUptodate(page);
1754 } else {
1755 ClearPageUptodate(page);
1756 SetPageError(page);
1757 }
1758 unlock_page(page);
1759 } else {
1760 if (uptodate) {
1761 check_page_uptodate(tree, page);
1762 } else {
1763 ClearPageUptodate(page);
1764 SetPageError(page);
1765 }
1766 check_page_locked(tree, page);
1767 }
1768 } while (bvec <= bvec_end);
1769
1770 bio_put(bio);
1771}
1772
1773struct bio *
1774btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
1775 gfp_t gfp_flags)
1776{
1777 struct bio *bio;
1778
1779 bio = bio_alloc(gfp_flags, nr_vecs);
1780
1781 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
1782 while (!bio && (nr_vecs /= 2))
1783 bio = bio_alloc(gfp_flags, nr_vecs);
1784 }
1785
1786 if (bio) {
1787 bio->bi_size = 0;
1788 bio->bi_bdev = bdev;
1789 bio->bi_sector = first_sector;
1790 }
1791 return bio;
1792}
1793
1794static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
1795 unsigned long bio_flags)
1796{
1797 int ret = 0;
1798 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1799 struct page *page = bvec->bv_page;
1800 struct extent_io_tree *tree = bio->bi_private;
1801 u64 start;
1802
1803 start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1804
1805 bio->bi_private = NULL;
1806
1807 bio_get(bio);
1808
1809 if (tree->ops && tree->ops->submit_bio_hook)
1810 ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1811 mirror_num, bio_flags, start);
1812 else
1813 submit_bio(rw, bio);
1814 if (bio_flagged(bio, BIO_EOPNOTSUPP))
1815 ret = -EOPNOTSUPP;
1816 bio_put(bio);
1817 return ret;
1818}
1819
1820static int submit_extent_page(int rw, struct extent_io_tree *tree,
1821 struct page *page, sector_t sector,
1822 size_t size, unsigned long offset,
1823 struct block_device *bdev,
1824 struct bio **bio_ret,
1825 unsigned long max_pages,
1826 bio_end_io_t end_io_func,
1827 int mirror_num,
1828 unsigned long prev_bio_flags,
1829 unsigned long bio_flags)
1830{
1831 int ret = 0;
1832 struct bio *bio;
1833 int nr;
1834 int contig = 0;
1835 int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
1836 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
1837 size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
1838
1839 if (bio_ret && *bio_ret) {
1840 bio = *bio_ret;
1841 if (old_compressed)
1842 contig = bio->bi_sector == sector;
1843 else
1844 contig = bio->bi_sector + (bio->bi_size >> 9) ==
1845 sector;
1846
1847 if (prev_bio_flags != bio_flags || !contig ||
1848 (tree->ops && tree->ops->merge_bio_hook &&
1849 tree->ops->merge_bio_hook(page, offset, page_size, bio,
1850 bio_flags)) ||
1851 bio_add_page(bio, page, page_size, offset) < page_size) {
1852 ret = submit_one_bio(rw, bio, mirror_num,
1853 prev_bio_flags);
1854 bio = NULL;
1855 } else {
1856 return 0;
1857 }
1858 }
1859 if (this_compressed)
1860 nr = BIO_MAX_PAGES;
1861 else
1862 nr = bio_get_nr_vecs(bdev);
1863
1864 bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1865 if (!bio)
1866 return -ENOMEM;
1867
1868 bio_add_page(bio, page, page_size, offset);
1869 bio->bi_end_io = end_io_func;
1870 bio->bi_private = tree;
1871
1872 if (bio_ret)
1873 *bio_ret = bio;
1874 else
1875 ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
1876
1877 return ret;
1878}
1879
1880void set_page_extent_mapped(struct page *page)
1881{
1882 if (!PagePrivate(page)) {
1883 SetPagePrivate(page);
1884 page_cache_get(page);
1885 set_page_private(page, EXTENT_PAGE_PRIVATE);
1886 }
1887}
1888
1889static void set_page_extent_head(struct page *page, unsigned long len)
1890{
1891 WARN_ON(!PagePrivate(page));
1892 set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
1893}
1894
1895/*
1896 * basic readpage implementation. Locked extent state structs are inserted
1897 * into the tree that are removed when the IO is done (by the end_io
1898 * handlers)
1899 */
1900static int __extent_read_full_page(struct extent_io_tree *tree,
1901 struct page *page,
1902 get_extent_t *get_extent,
1903 struct bio **bio, int mirror_num,
1904 unsigned long *bio_flags)
1905{
1906 struct inode *inode = page->mapping->host;
1907 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1908 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1909 u64 end;
1910 u64 cur = start;
1911 u64 extent_offset;
1912 u64 last_byte = i_size_read(inode);
1913 u64 block_start;
1914 u64 cur_end;
1915 sector_t sector;
1916 struct extent_map *em;
1917 struct block_device *bdev;
1918 struct btrfs_ordered_extent *ordered;
1919 int ret;
1920 int nr = 0;
1921 size_t pg_offset = 0;
1922 size_t iosize;
1923 size_t disk_io_size;
1924 size_t blocksize = inode->i_sb->s_blocksize;
1925 unsigned long this_bio_flag = 0;
1926
1927 set_page_extent_mapped(page);
1928
1929 if (!PageUptodate(page)) {
1930 if (cleancache_get_page(page) == 0) {
1931 BUG_ON(blocksize != PAGE_SIZE);
1932 goto out;
1933 }
1934 }
1935
1936 end = page_end;
1937 while (1) {
1938 lock_extent(tree, start, end, GFP_NOFS);
1939 ordered = btrfs_lookup_ordered_extent(inode, start);
1940 if (!ordered)
1941 break;
1942 unlock_extent(tree, start, end, GFP_NOFS);
1943 btrfs_start_ordered_extent(inode, ordered, 1);
1944 btrfs_put_ordered_extent(ordered);
1945 }
1946
1947 if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
1948 char *userpage;
1949 size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
1950
1951 if (zero_offset) {
1952 iosize = PAGE_CACHE_SIZE - zero_offset;
1953 userpage = kmap_atomic(page, KM_USER0);
1954 memset(userpage + zero_offset, 0, iosize);
1955 flush_dcache_page(page);
1956 kunmap_atomic(userpage, KM_USER0);
1957 }
1958 }
1959 while (cur <= end) {
1960 if (cur >= last_byte) {
1961 char *userpage;
1962 struct extent_state *cached = NULL;
1963
1964 iosize = PAGE_CACHE_SIZE - pg_offset;
1965 userpage = kmap_atomic(page, KM_USER0);
1966 memset(userpage + pg_offset, 0, iosize);
1967 flush_dcache_page(page);
1968 kunmap_atomic(userpage, KM_USER0);
1969 set_extent_uptodate(tree, cur, cur + iosize - 1,
1970 &cached, GFP_NOFS);
1971 unlock_extent_cached(tree, cur, cur + iosize - 1,
1972 &cached, GFP_NOFS);
1973 break;
1974 }
1975 em = get_extent(inode, page, pg_offset, cur,
1976 end - cur + 1, 0);
1977 if (IS_ERR_OR_NULL(em)) {
1978 SetPageError(page);
1979 unlock_extent(tree, cur, end, GFP_NOFS);
1980 break;
1981 }
1982 extent_offset = cur - em->start;
1983 BUG_ON(extent_map_end(em) <= cur);
1984 BUG_ON(end < cur);
1985
1986 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1987 this_bio_flag = EXTENT_BIO_COMPRESSED;
1988 extent_set_compress_type(&this_bio_flag,
1989 em->compress_type);
1990 }
1991
1992 iosize = min(extent_map_end(em) - cur, end - cur + 1);
1993 cur_end = min(extent_map_end(em) - 1, end);
1994 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
1995 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
1996 disk_io_size = em->block_len;
1997 sector = em->block_start >> 9;
1998 } else {
1999 sector = (em->block_start + extent_offset) >> 9;
2000 disk_io_size = iosize;
2001 }
2002 bdev = em->bdev;
2003 block_start = em->block_start;
2004 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2005 block_start = EXTENT_MAP_HOLE;
2006 free_extent_map(em);
2007 em = NULL;
2008
2009 /* we've found a hole, just zero and go on */
2010 if (block_start == EXTENT_MAP_HOLE) {
2011 char *userpage;
2012 struct extent_state *cached = NULL;
2013
2014 userpage = kmap_atomic(page, KM_USER0);
2015 memset(userpage + pg_offset, 0, iosize);
2016 flush_dcache_page(page);
2017 kunmap_atomic(userpage, KM_USER0);
2018
2019 set_extent_uptodate(tree, cur, cur + iosize - 1,
2020 &cached, GFP_NOFS);
2021 unlock_extent_cached(tree, cur, cur + iosize - 1,
2022 &cached, GFP_NOFS);
2023 cur = cur + iosize;
2024 pg_offset += iosize;
2025 continue;
2026 }
2027 /* the get_extent function already copied into the page */
2028 if (test_range_bit(tree, cur, cur_end,
2029 EXTENT_UPTODATE, 1, NULL)) {
2030 check_page_uptodate(tree, page);
2031 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2032 cur = cur + iosize;
2033 pg_offset += iosize;
2034 continue;
2035 }
2036 /* we have an inline extent but it didn't get marked up
2037 * to date. Error out
2038 */
2039 if (block_start == EXTENT_MAP_INLINE) {
2040 SetPageError(page);
2041 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2042 cur = cur + iosize;
2043 pg_offset += iosize;
2044 continue;
2045 }
2046
2047 ret = 0;
2048 if (tree->ops && tree->ops->readpage_io_hook) {
2049 ret = tree->ops->readpage_io_hook(page, cur,
2050 cur + iosize - 1);
2051 }
2052 if (!ret) {
2053 unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
2054 pnr -= page->index;
2055 ret = submit_extent_page(READ, tree, page,
2056 sector, disk_io_size, pg_offset,
2057 bdev, bio, pnr,
2058 end_bio_extent_readpage, mirror_num,
2059 *bio_flags,
2060 this_bio_flag);
2061 nr++;
2062 *bio_flags = this_bio_flag;
2063 }
2064 if (ret)
2065 SetPageError(page);
2066 cur = cur + iosize;
2067 pg_offset += iosize;
2068 }
2069out:
2070 if (!nr) {
2071 if (!PageError(page))
2072 SetPageUptodate(page);
2073 unlock_page(page);
2074 }
2075 return 0;
2076}
2077
2078int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
2079 get_extent_t *get_extent)
2080{
2081 struct bio *bio = NULL;
2082 unsigned long bio_flags = 0;
2083 int ret;
2084
2085 ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
2086 &bio_flags);
2087 if (bio)
2088 ret = submit_one_bio(READ, bio, 0, bio_flags);
2089 return ret;
2090}
2091
2092static noinline void update_nr_written(struct page *page,
2093 struct writeback_control *wbc,
2094 unsigned long nr_written)
2095{
2096 wbc->nr_to_write -= nr_written;
2097 if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
2098 wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
2099 page->mapping->writeback_index = page->index + nr_written;
2100}
2101
2102/*
2103 * the writepage semantics are similar to regular writepage. extent
2104 * records are inserted to lock ranges in the tree, and as dirty areas
2105 * are found, they are marked writeback. Then the lock bits are removed
2106 * and the end_io handler clears the writeback ranges
2107 */
2108static int __extent_writepage(struct page *page, struct writeback_control *wbc,
2109 void *data)
2110{
2111 struct inode *inode = page->mapping->host;
2112 struct extent_page_data *epd = data;
2113 struct extent_io_tree *tree = epd->tree;
2114 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2115 u64 delalloc_start;
2116 u64 page_end = start + PAGE_CACHE_SIZE - 1;
2117 u64 end;
2118 u64 cur = start;
2119 u64 extent_offset;
2120 u64 last_byte = i_size_read(inode);
2121 u64 block_start;
2122 u64 iosize;
2123 sector_t sector;
2124 struct extent_state *cached_state = NULL;
2125 struct extent_map *em;
2126 struct block_device *bdev;
2127 int ret;
2128 int nr = 0;
2129 size_t pg_offset = 0;
2130 size_t blocksize;
2131 loff_t i_size = i_size_read(inode);
2132 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2133 u64 nr_delalloc;
2134 u64 delalloc_end;
2135 int page_started;
2136 int compressed;
2137 int write_flags;
2138 unsigned long nr_written = 0;
2139
2140 if (wbc->sync_mode == WB_SYNC_ALL)
2141 write_flags = WRITE_SYNC;
2142 else
2143 write_flags = WRITE;
2144
2145 trace___extent_writepage(page, inode, wbc);
2146
2147 WARN_ON(!PageLocked(page));
2148 pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2149 if (page->index > end_index ||
2150 (page->index == end_index && !pg_offset)) {
2151 page->mapping->a_ops->invalidatepage(page, 0);
2152 unlock_page(page);
2153 return 0;
2154 }
2155
2156 if (page->index == end_index) {
2157 char *userpage;
2158
2159 userpage = kmap_atomic(page, KM_USER0);
2160 memset(userpage + pg_offset, 0,
2161 PAGE_CACHE_SIZE - pg_offset);
2162 kunmap_atomic(userpage, KM_USER0);
2163 flush_dcache_page(page);
2164 }
2165 pg_offset = 0;
2166
2167 set_page_extent_mapped(page);
2168
2169 delalloc_start = start;
2170 delalloc_end = 0;
2171 page_started = 0;
2172 if (!epd->extent_locked) {
2173 u64 delalloc_to_write = 0;
2174 /*
2175 * make sure the wbc mapping index is at least updated
2176 * to this page.
2177 */
2178 update_nr_written(page, wbc, 0);
2179
2180 while (delalloc_end < page_end) {
2181 nr_delalloc = find_lock_delalloc_range(inode, tree,
2182 page,
2183 &delalloc_start,
2184 &delalloc_end,
2185 128 * 1024 * 1024);
2186 if (nr_delalloc == 0) {
2187 delalloc_start = delalloc_end + 1;
2188 continue;
2189 }
2190 tree->ops->fill_delalloc(inode, page, delalloc_start,
2191 delalloc_end, &page_started,
2192 &nr_written);
2193 /*
2194 * delalloc_end is already one less than the total
2195 * length, so we don't subtract one from
2196 * PAGE_CACHE_SIZE
2197 */
2198 delalloc_to_write += (delalloc_end - delalloc_start +
2199 PAGE_CACHE_SIZE) >>
2200 PAGE_CACHE_SHIFT;
2201 delalloc_start = delalloc_end + 1;
2202 }
2203 if (wbc->nr_to_write < delalloc_to_write) {
2204 int thresh = 8192;
2205
2206 if (delalloc_to_write < thresh * 2)
2207 thresh = delalloc_to_write;
2208 wbc->nr_to_write = min_t(u64, delalloc_to_write,
2209 thresh);
2210 }
2211
2212 /* did the fill delalloc function already unlock and start
2213 * the IO?
2214 */
2215 if (page_started) {
2216 ret = 0;
2217 /*
2218 * we've unlocked the page, so we can't update
2219 * the mapping's writeback index, just update
2220 * nr_to_write.
2221 */
2222 wbc->nr_to_write -= nr_written;
2223 goto done_unlocked;
2224 }
2225 }
2226 if (tree->ops && tree->ops->writepage_start_hook) {
2227 ret = tree->ops->writepage_start_hook(page, start,
2228 page_end);
2229 if (ret == -EAGAIN) {
2230 redirty_page_for_writepage(wbc, page);
2231 update_nr_written(page, wbc, nr_written);
2232 unlock_page(page);
2233 ret = 0;
2234 goto done_unlocked;
2235 }
2236 }
2237
2238 /*
2239 * we don't want to touch the inode after unlocking the page,
2240 * so we update the mapping writeback index now
2241 */
2242 update_nr_written(page, wbc, nr_written + 1);
2243
2244 end = page_end;
2245 if (last_byte <= start) {
2246 if (tree->ops && tree->ops->writepage_end_io_hook)
2247 tree->ops->writepage_end_io_hook(page, start,
2248 page_end, NULL, 1);
2249 goto done;
2250 }
2251
2252 blocksize = inode->i_sb->s_blocksize;
2253
2254 while (cur <= end) {
2255 if (cur >= last_byte) {
2256 if (tree->ops && tree->ops->writepage_end_io_hook)
2257 tree->ops->writepage_end_io_hook(page, cur,
2258 page_end, NULL, 1);
2259 break;
2260 }
2261 em = epd->get_extent(inode, page, pg_offset, cur,
2262 end - cur + 1, 1);
2263 if (IS_ERR_OR_NULL(em)) {
2264 SetPageError(page);
2265 break;
2266 }
2267
2268 extent_offset = cur - em->start;
2269 BUG_ON(extent_map_end(em) <= cur);
2270 BUG_ON(end < cur);
2271 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2272 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2273 sector = (em->block_start + extent_offset) >> 9;
2274 bdev = em->bdev;
2275 block_start = em->block_start;
2276 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2277 free_extent_map(em);
2278 em = NULL;
2279
2280 /*
2281 * compressed and inline extents are written through other
2282 * paths in the FS
2283 */
2284 if (compressed || block_start == EXTENT_MAP_HOLE ||
2285 block_start == EXTENT_MAP_INLINE) {
2286 /*
2287 * end_io notification does not happen here for
2288 * compressed extents
2289 */
2290 if (!compressed && tree->ops &&
2291 tree->ops->writepage_end_io_hook)
2292 tree->ops->writepage_end_io_hook(page, cur,
2293 cur + iosize - 1,
2294 NULL, 1);
2295 else if (compressed) {
2296 /* we don't want to end_page_writeback on
2297 * a compressed extent. this happens
2298 * elsewhere
2299 */
2300 nr++;
2301 }
2302
2303 cur += iosize;
2304 pg_offset += iosize;
2305 continue;
2306 }
2307 /* leave this out until we have a page_mkwrite call */
2308 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2309 EXTENT_DIRTY, 0, NULL)) {
2310 cur = cur + iosize;
2311 pg_offset += iosize;
2312 continue;
2313 }
2314
2315 if (tree->ops && tree->ops->writepage_io_hook) {
2316 ret = tree->ops->writepage_io_hook(page, cur,
2317 cur + iosize - 1);
2318 } else {
2319 ret = 0;
2320 }
2321 if (ret) {
2322 SetPageError(page);
2323 } else {
2324 unsigned long max_nr = end_index + 1;
2325
2326 set_range_writeback(tree, cur, cur + iosize - 1);
2327 if (!PageWriteback(page)) {
2328 printk(KERN_ERR "btrfs warning page %lu not "
2329 "writeback, cur %llu end %llu\n",
2330 page->index, (unsigned long long)cur,
2331 (unsigned long long)end);
2332 }
2333
2334 ret = submit_extent_page(write_flags, tree, page,
2335 sector, iosize, pg_offset,
2336 bdev, &epd->bio, max_nr,
2337 end_bio_extent_writepage,
2338 0, 0, 0);
2339 if (ret)
2340 SetPageError(page);
2341 }
2342 cur = cur + iosize;
2343 pg_offset += iosize;
2344 nr++;
2345 }
2346done:
2347 if (nr == 0) {
2348 /* make sure the mapping tag for page dirty gets cleared */
2349 set_page_writeback(page);
2350 end_page_writeback(page);
2351 }
2352 unlock_page(page);
2353
2354done_unlocked:
2355
2356 /* drop our reference on any cached states */
2357 free_extent_state(cached_state);
2358 return 0;
2359}
2360
2361/**
2362 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
2363 * @mapping: address space structure to write
2364 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
2365 * @writepage: function called for each page
2366 * @data: data passed to writepage function
2367 *
2368 * If a page is already under I/O, write_cache_pages() skips it, even
2369 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
2370 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
2371 * and msync() need to guarantee that all the data which was dirty at the time
2372 * the call was made get new I/O started against them. If wbc->sync_mode is
2373 * WB_SYNC_ALL then we were called for data integrity and we must wait for
2374 * existing IO to complete.
2375 */
2376static int extent_write_cache_pages(struct extent_io_tree *tree,
2377 struct address_space *mapping,
2378 struct writeback_control *wbc,
2379 writepage_t writepage, void *data,
2380 void (*flush_fn)(void *))
2381{
2382 int ret = 0;
2383 int done = 0;
2384 int nr_to_write_done = 0;
2385 struct pagevec pvec;
2386 int nr_pages;
2387 pgoff_t index;
2388 pgoff_t end; /* Inclusive */
2389 int scanned = 0;
2390 int tag;
2391
2392 pagevec_init(&pvec, 0);
2393 if (wbc->range_cyclic) {
2394 index = mapping->writeback_index; /* Start from prev offset */
2395 end = -1;
2396 } else {
2397 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2398 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2399 scanned = 1;
2400 }
2401 if (wbc->sync_mode == WB_SYNC_ALL)
2402 tag = PAGECACHE_TAG_TOWRITE;
2403 else
2404 tag = PAGECACHE_TAG_DIRTY;
2405retry:
2406 if (wbc->sync_mode == WB_SYNC_ALL)
2407 tag_pages_for_writeback(mapping, index, end);
2408 while (!done && !nr_to_write_done && (index <= end) &&
2409 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2410 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2411 unsigned i;
2412
2413 scanned = 1;
2414 for (i = 0; i < nr_pages; i++) {
2415 struct page *page = pvec.pages[i];
2416
2417 /*
2418 * At this point we hold neither mapping->tree_lock nor
2419 * lock on the page itself: the page may be truncated or
2420 * invalidated (changing page->mapping to NULL), or even
2421 * swizzled back from swapper_space to tmpfs file
2422 * mapping
2423 */
2424 if (tree->ops && tree->ops->write_cache_pages_lock_hook)
2425 tree->ops->write_cache_pages_lock_hook(page);
2426 else
2427 lock_page(page);
2428
2429 if (unlikely(page->mapping != mapping)) {
2430 unlock_page(page);
2431 continue;
2432 }
2433
2434 if (!wbc->range_cyclic && page->index > end) {
2435 done = 1;
2436 unlock_page(page);
2437 continue;
2438 }
2439
2440 if (wbc->sync_mode != WB_SYNC_NONE) {
2441 if (PageWriteback(page))
2442 flush_fn(data);
2443 wait_on_page_writeback(page);
2444 }
2445
2446 if (PageWriteback(page) ||
2447 !clear_page_dirty_for_io(page)) {
2448 unlock_page(page);
2449 continue;
2450 }
2451
2452 ret = (*writepage)(page, wbc, data);
2453
2454 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
2455 unlock_page(page);
2456 ret = 0;
2457 }
2458 if (ret)
2459 done = 1;
2460
2461 /*
2462 * the filesystem may choose to bump up nr_to_write.
2463 * We have to make sure to honor the new nr_to_write
2464 * at any time
2465 */
2466 nr_to_write_done = wbc->nr_to_write <= 0;
2467 }
2468 pagevec_release(&pvec);
2469 cond_resched();
2470 }
2471 if (!scanned && !done) {
2472 /*
2473 * We hit the last page and there is more work to be done: wrap
2474 * back to the start of the file
2475 */
2476 scanned = 1;
2477 index = 0;
2478 goto retry;
2479 }
2480 return ret;
2481}
2482
2483static void flush_epd_write_bio(struct extent_page_data *epd)
2484{
2485 if (epd->bio) {
2486 if (epd->sync_io)
2487 submit_one_bio(WRITE_SYNC, epd->bio, 0, 0);
2488 else
2489 submit_one_bio(WRITE, epd->bio, 0, 0);
2490 epd->bio = NULL;
2491 }
2492}
2493
2494static noinline void flush_write_bio(void *data)
2495{
2496 struct extent_page_data *epd = data;
2497 flush_epd_write_bio(epd);
2498}
2499
2500int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
2501 get_extent_t *get_extent,
2502 struct writeback_control *wbc)
2503{
2504 int ret;
2505 struct extent_page_data epd = {
2506 .bio = NULL,
2507 .tree = tree,
2508 .get_extent = get_extent,
2509 .extent_locked = 0,
2510 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2511 };
2512
2513 ret = __extent_writepage(page, wbc, &epd);
2514
2515 flush_epd_write_bio(&epd);
2516 return ret;
2517}
2518
2519int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
2520 u64 start, u64 end, get_extent_t *get_extent,
2521 int mode)
2522{
2523 int ret = 0;
2524 struct address_space *mapping = inode->i_mapping;
2525 struct page *page;
2526 unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
2527 PAGE_CACHE_SHIFT;
2528
2529 struct extent_page_data epd = {
2530 .bio = NULL,
2531 .tree = tree,
2532 .get_extent = get_extent,
2533 .extent_locked = 1,
2534 .sync_io = mode == WB_SYNC_ALL,
2535 };
2536 struct writeback_control wbc_writepages = {
2537 .sync_mode = mode,
2538 .nr_to_write = nr_pages * 2,
2539 .range_start = start,
2540 .range_end = end + 1,
2541 };
2542
2543 while (start <= end) {
2544 page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
2545 if (clear_page_dirty_for_io(page))
2546 ret = __extent_writepage(page, &wbc_writepages, &epd);
2547 else {
2548 if (tree->ops && tree->ops->writepage_end_io_hook)
2549 tree->ops->writepage_end_io_hook(page, start,
2550 start + PAGE_CACHE_SIZE - 1,
2551 NULL, 1);
2552 unlock_page(page);
2553 }
2554 page_cache_release(page);
2555 start += PAGE_CACHE_SIZE;
2556 }
2557
2558 flush_epd_write_bio(&epd);
2559 return ret;
2560}
2561
2562int extent_writepages(struct extent_io_tree *tree,
2563 struct address_space *mapping,
2564 get_extent_t *get_extent,
2565 struct writeback_control *wbc)
2566{
2567 int ret = 0;
2568 struct extent_page_data epd = {
2569 .bio = NULL,
2570 .tree = tree,
2571 .get_extent = get_extent,
2572 .extent_locked = 0,
2573 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2574 };
2575
2576 ret = extent_write_cache_pages(tree, mapping, wbc,
2577 __extent_writepage, &epd,
2578 flush_write_bio);
2579 flush_epd_write_bio(&epd);
2580 return ret;
2581}
2582
2583int extent_readpages(struct extent_io_tree *tree,
2584 struct address_space *mapping,
2585 struct list_head *pages, unsigned nr_pages,
2586 get_extent_t get_extent)
2587{
2588 struct bio *bio = NULL;
2589 unsigned page_idx;
2590 unsigned long bio_flags = 0;
2591
2592 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
2593 struct page *page = list_entry(pages->prev, struct page, lru);
2594
2595 prefetchw(&page->flags);
2596 list_del(&page->lru);
2597 if (!add_to_page_cache_lru(page, mapping,
2598 page->index, GFP_NOFS)) {
2599 __extent_read_full_page(tree, page, get_extent,
2600 &bio, 0, &bio_flags);
2601 }
2602 page_cache_release(page);
2603 }
2604 BUG_ON(!list_empty(pages));
2605 if (bio)
2606 submit_one_bio(READ, bio, 0, bio_flags);
2607 return 0;
2608}
2609
2610/*
2611 * basic invalidatepage code, this waits on any locked or writeback
2612 * ranges corresponding to the page, and then deletes any extent state
2613 * records from the tree
2614 */
2615int extent_invalidatepage(struct extent_io_tree *tree,
2616 struct page *page, unsigned long offset)
2617{
2618 struct extent_state *cached_state = NULL;
2619 u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
2620 u64 end = start + PAGE_CACHE_SIZE - 1;
2621 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
2622
2623 start += (offset + blocksize - 1) & ~(blocksize - 1);
2624 if (start > end)
2625 return 0;
2626
2627 lock_extent_bits(tree, start, end, 0, &cached_state, GFP_NOFS);
2628 wait_on_page_writeback(page);
2629 clear_extent_bit(tree, start, end,
2630 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
2631 EXTENT_DO_ACCOUNTING,
2632 1, 1, &cached_state, GFP_NOFS);
2633 return 0;
2634}
2635
2636/*
2637 * a helper for releasepage, this tests for areas of the page that
2638 * are locked or under IO and drops the related state bits if it is safe
2639 * to drop the page.
2640 */
2641int try_release_extent_state(struct extent_map_tree *map,
2642 struct extent_io_tree *tree, struct page *page,
2643 gfp_t mask)
2644{
2645 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2646 u64 end = start + PAGE_CACHE_SIZE - 1;
2647 int ret = 1;
2648
2649 if (test_range_bit(tree, start, end,
2650 EXTENT_IOBITS, 0, NULL))
2651 ret = 0;
2652 else {
2653 if ((mask & GFP_NOFS) == GFP_NOFS)
2654 mask = GFP_NOFS;
2655 /*
2656 * at this point we can safely clear everything except the
2657 * locked bit and the nodatasum bit
2658 */
2659 ret = clear_extent_bit(tree, start, end,
2660 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
2661 0, 0, NULL, mask);
2662
2663 /* if clear_extent_bit failed for enomem reasons,
2664 * we can't allow the release to continue.
2665 */
2666 if (ret < 0)
2667 ret = 0;
2668 else
2669 ret = 1;
2670 }
2671 return ret;
2672}
2673
2674/*
2675 * a helper for releasepage. As long as there are no locked extents
2676 * in the range corresponding to the page, both state records and extent
2677 * map records are removed
2678 */
2679int try_release_extent_mapping(struct extent_map_tree *map,
2680 struct extent_io_tree *tree, struct page *page,
2681 gfp_t mask)
2682{
2683 struct extent_map *em;
2684 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2685 u64 end = start + PAGE_CACHE_SIZE - 1;
2686
2687 if ((mask & __GFP_WAIT) &&
2688 page->mapping->host->i_size > 16 * 1024 * 1024) {
2689 u64 len;
2690 while (start <= end) {
2691 len = end - start + 1;
2692 write_lock(&map->lock);
2693 em = lookup_extent_mapping(map, start, len);
2694 if (IS_ERR_OR_NULL(em)) {
2695 write_unlock(&map->lock);
2696 break;
2697 }
2698 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
2699 em->start != start) {
2700 write_unlock(&map->lock);
2701 free_extent_map(em);
2702 break;
2703 }
2704 if (!test_range_bit(tree, em->start,
2705 extent_map_end(em) - 1,
2706 EXTENT_LOCKED | EXTENT_WRITEBACK,
2707 0, NULL)) {
2708 remove_extent_mapping(map, em);
2709 /* once for the rb tree */
2710 free_extent_map(em);
2711 }
2712 start = extent_map_end(em);
2713 write_unlock(&map->lock);
2714
2715 /* once for us */
2716 free_extent_map(em);
2717 }
2718 }
2719 return try_release_extent_state(map, tree, page, mask);
2720}
2721
2722/*
2723 * helper function for fiemap, which doesn't want to see any holes.
2724 * This maps until we find something past 'last'
2725 */
2726static struct extent_map *get_extent_skip_holes(struct inode *inode,
2727 u64 offset,
2728 u64 last,
2729 get_extent_t *get_extent)
2730{
2731 u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
2732 struct extent_map *em;
2733 u64 len;
2734
2735 if (offset >= last)
2736 return NULL;
2737
2738 while(1) {
2739 len = last - offset;
2740 if (len == 0)
2741 break;
2742 len = (len + sectorsize - 1) & ~(sectorsize - 1);
2743 em = get_extent(inode, NULL, 0, offset, len, 0);
2744 if (IS_ERR_OR_NULL(em))
2745 return em;
2746
2747 /* if this isn't a hole return it */
2748 if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
2749 em->block_start != EXTENT_MAP_HOLE) {
2750 return em;
2751 }
2752
2753 /* this is a hole, advance to the next extent */
2754 offset = extent_map_end(em);
2755 free_extent_map(em);
2756 if (offset >= last)
2757 break;
2758 }
2759 return NULL;
2760}
2761
2762int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
2763 __u64 start, __u64 len, get_extent_t *get_extent)
2764{
2765 int ret = 0;
2766 u64 off = start;
2767 u64 max = start + len;
2768 u32 flags = 0;
2769 u32 found_type;
2770 u64 last;
2771 u64 last_for_get_extent = 0;
2772 u64 disko = 0;
2773 u64 isize = i_size_read(inode);
2774 struct btrfs_key found_key;
2775 struct extent_map *em = NULL;
2776 struct extent_state *cached_state = NULL;
2777 struct btrfs_path *path;
2778 struct btrfs_file_extent_item *item;
2779 int end = 0;
2780 u64 em_start = 0;
2781 u64 em_len = 0;
2782 u64 em_end = 0;
2783 unsigned long emflags;
2784
2785 if (len == 0)
2786 return -EINVAL;
2787
2788 path = btrfs_alloc_path();
2789 if (!path)
2790 return -ENOMEM;
2791 path->leave_spinning = 1;
2792
2793 /*
2794 * lookup the last file extent. We're not using i_size here
2795 * because there might be preallocation past i_size
2796 */
2797 ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
2798 path, btrfs_ino(inode), -1, 0);
2799 if (ret < 0) {
2800 btrfs_free_path(path);
2801 return ret;
2802 }
2803 WARN_ON(!ret);
2804 path->slots[0]--;
2805 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2806 struct btrfs_file_extent_item);
2807 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
2808 found_type = btrfs_key_type(&found_key);
2809
2810 /* No extents, but there might be delalloc bits */
2811 if (found_key.objectid != btrfs_ino(inode) ||
2812 found_type != BTRFS_EXTENT_DATA_KEY) {
2813 /* have to trust i_size as the end */
2814 last = (u64)-1;
2815 last_for_get_extent = isize;
2816 } else {
2817 /*
2818 * remember the start of the last extent. There are a
2819 * bunch of different factors that go into the length of the
2820 * extent, so its much less complex to remember where it started
2821 */
2822 last = found_key.offset;
2823 last_for_get_extent = last + 1;
2824 }
2825 btrfs_free_path(path);
2826
2827 /*
2828 * we might have some extents allocated but more delalloc past those
2829 * extents. so, we trust isize unless the start of the last extent is
2830 * beyond isize
2831 */
2832 if (last < isize) {
2833 last = (u64)-1;
2834 last_for_get_extent = isize;
2835 }
2836
2837 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
2838 &cached_state, GFP_NOFS);
2839
2840 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2841 get_extent);
2842 if (!em)
2843 goto out;
2844 if (IS_ERR(em)) {
2845 ret = PTR_ERR(em);
2846 goto out;
2847 }
2848
2849 while (!end) {
2850 u64 offset_in_extent;
2851
2852 /* break if the extent we found is outside the range */
2853 if (em->start >= max || extent_map_end(em) < off)
2854 break;
2855
2856 /*
2857 * get_extent may return an extent that starts before our
2858 * requested range. We have to make sure the ranges
2859 * we return to fiemap always move forward and don't
2860 * overlap, so adjust the offsets here
2861 */
2862 em_start = max(em->start, off);
2863
2864 /*
2865 * record the offset from the start of the extent
2866 * for adjusting the disk offset below
2867 */
2868 offset_in_extent = em_start - em->start;
2869 em_end = extent_map_end(em);
2870 em_len = em_end - em_start;
2871 emflags = em->flags;
2872 disko = 0;
2873 flags = 0;
2874
2875 /*
2876 * bump off for our next call to get_extent
2877 */
2878 off = extent_map_end(em);
2879 if (off >= max)
2880 end = 1;
2881
2882 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
2883 end = 1;
2884 flags |= FIEMAP_EXTENT_LAST;
2885 } else if (em->block_start == EXTENT_MAP_INLINE) {
2886 flags |= (FIEMAP_EXTENT_DATA_INLINE |
2887 FIEMAP_EXTENT_NOT_ALIGNED);
2888 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
2889 flags |= (FIEMAP_EXTENT_DELALLOC |
2890 FIEMAP_EXTENT_UNKNOWN);
2891 } else {
2892 disko = em->block_start + offset_in_extent;
2893 }
2894 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
2895 flags |= FIEMAP_EXTENT_ENCODED;
2896
2897 free_extent_map(em);
2898 em = NULL;
2899 if ((em_start >= last) || em_len == (u64)-1 ||
2900 (last == (u64)-1 && isize <= em_end)) {
2901 flags |= FIEMAP_EXTENT_LAST;
2902 end = 1;
2903 }
2904
2905 /* now scan forward to see if this is really the last extent. */
2906 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2907 get_extent);
2908 if (IS_ERR(em)) {
2909 ret = PTR_ERR(em);
2910 goto out;
2911 }
2912 if (!em) {
2913 flags |= FIEMAP_EXTENT_LAST;
2914 end = 1;
2915 }
2916 ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
2917 em_len, flags);
2918 if (ret)
2919 goto out_free;
2920 }
2921out_free:
2922 free_extent_map(em);
2923out:
2924 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len,
2925 &cached_state, GFP_NOFS);
2926 return ret;
2927}
2928
2929static inline struct page *extent_buffer_page(struct extent_buffer *eb,
2930 unsigned long i)
2931{
2932 struct page *p;
2933 struct address_space *mapping;
2934
2935 if (i == 0)
2936 return eb->first_page;
2937 i += eb->start >> PAGE_CACHE_SHIFT;
2938 mapping = eb->first_page->mapping;
2939 if (!mapping)
2940 return NULL;
2941
2942 /*
2943 * extent_buffer_page is only called after pinning the page
2944 * by increasing the reference count. So we know the page must
2945 * be in the radix tree.
2946 */
2947 rcu_read_lock();
2948 p = radix_tree_lookup(&mapping->page_tree, i);
2949 rcu_read_unlock();
2950
2951 return p;
2952}
2953
2954static inline unsigned long num_extent_pages(u64 start, u64 len)
2955{
2956 return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
2957 (start >> PAGE_CACHE_SHIFT);
2958}
2959
2960static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
2961 u64 start,
2962 unsigned long len,
2963 gfp_t mask)
2964{
2965 struct extent_buffer *eb = NULL;
2966#if LEAK_DEBUG
2967 unsigned long flags;
2968#endif
2969
2970 eb = kmem_cache_zalloc(extent_buffer_cache, mask);
2971 if (eb == NULL)
2972 return NULL;
2973 eb->start = start;
2974 eb->len = len;
2975 rwlock_init(&eb->lock);
2976 atomic_set(&eb->write_locks, 0);
2977 atomic_set(&eb->read_locks, 0);
2978 atomic_set(&eb->blocking_readers, 0);
2979 atomic_set(&eb->blocking_writers, 0);
2980 atomic_set(&eb->spinning_readers, 0);
2981 atomic_set(&eb->spinning_writers, 0);
2982 init_waitqueue_head(&eb->write_lock_wq);
2983 init_waitqueue_head(&eb->read_lock_wq);
2984
2985#if LEAK_DEBUG
2986 spin_lock_irqsave(&leak_lock, flags);
2987 list_add(&eb->leak_list, &buffers);
2988 spin_unlock_irqrestore(&leak_lock, flags);
2989#endif
2990 atomic_set(&eb->refs, 1);
2991
2992 return eb;
2993}
2994
2995static void __free_extent_buffer(struct extent_buffer *eb)
2996{
2997#if LEAK_DEBUG
2998 unsigned long flags;
2999 spin_lock_irqsave(&leak_lock, flags);
3000 list_del(&eb->leak_list);
3001 spin_unlock_irqrestore(&leak_lock, flags);
3002#endif
3003 kmem_cache_free(extent_buffer_cache, eb);
3004}
3005
3006/*
3007 * Helper for releasing extent buffer page.
3008 */
3009static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
3010 unsigned long start_idx)
3011{
3012 unsigned long index;
3013 struct page *page;
3014
3015 if (!eb->first_page)
3016 return;
3017
3018 index = num_extent_pages(eb->start, eb->len);
3019 if (start_idx >= index)
3020 return;
3021
3022 do {
3023 index--;
3024 page = extent_buffer_page(eb, index);
3025 if (page)
3026 page_cache_release(page);
3027 } while (index != start_idx);
3028}
3029
3030/*
3031 * Helper for releasing the extent buffer.
3032 */
3033static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
3034{
3035 btrfs_release_extent_buffer_page(eb, 0);
3036 __free_extent_buffer(eb);
3037}
3038
3039struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
3040 u64 start, unsigned long len,
3041 struct page *page0)
3042{
3043 unsigned long num_pages = num_extent_pages(start, len);
3044 unsigned long i;
3045 unsigned long index = start >> PAGE_CACHE_SHIFT;
3046 struct extent_buffer *eb;
3047 struct extent_buffer *exists = NULL;
3048 struct page *p;
3049 struct address_space *mapping = tree->mapping;
3050 int uptodate = 1;
3051 int ret;
3052
3053 rcu_read_lock();
3054 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3055 if (eb && atomic_inc_not_zero(&eb->refs)) {
3056 rcu_read_unlock();
3057 mark_page_accessed(eb->first_page);
3058 return eb;
3059 }
3060 rcu_read_unlock();
3061
3062 eb = __alloc_extent_buffer(tree, start, len, GFP_NOFS);
3063 if (!eb)
3064 return NULL;
3065
3066 if (page0) {
3067 eb->first_page = page0;
3068 i = 1;
3069 index++;
3070 page_cache_get(page0);
3071 mark_page_accessed(page0);
3072 set_page_extent_mapped(page0);
3073 set_page_extent_head(page0, len);
3074 uptodate = PageUptodate(page0);
3075 } else {
3076 i = 0;
3077 }
3078 for (; i < num_pages; i++, index++) {
3079 p = find_or_create_page(mapping, index, GFP_NOFS);
3080 if (!p) {
3081 WARN_ON(1);
3082 goto free_eb;
3083 }
3084 set_page_extent_mapped(p);
3085 mark_page_accessed(p);
3086 if (i == 0) {
3087 eb->first_page = p;
3088 set_page_extent_head(p, len);
3089 } else {
3090 set_page_private(p, EXTENT_PAGE_PRIVATE);
3091 }
3092 if (!PageUptodate(p))
3093 uptodate = 0;
3094
3095 /*
3096 * see below about how we avoid a nasty race with release page
3097 * and why we unlock later
3098 */
3099 if (i != 0)
3100 unlock_page(p);
3101 }
3102 if (uptodate)
3103 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3104
3105 ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
3106 if (ret)
3107 goto free_eb;
3108
3109 spin_lock(&tree->buffer_lock);
3110 ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
3111 if (ret == -EEXIST) {
3112 exists = radix_tree_lookup(&tree->buffer,
3113 start >> PAGE_CACHE_SHIFT);
3114 /* add one reference for the caller */
3115 atomic_inc(&exists->refs);
3116 spin_unlock(&tree->buffer_lock);
3117 radix_tree_preload_end();
3118 goto free_eb;
3119 }
3120 /* add one reference for the tree */
3121 atomic_inc(&eb->refs);
3122 spin_unlock(&tree->buffer_lock);
3123 radix_tree_preload_end();
3124
3125 /*
3126 * there is a race where release page may have
3127 * tried to find this extent buffer in the radix
3128 * but failed. It will tell the VM it is safe to
3129 * reclaim the, and it will clear the page private bit.
3130 * We must make sure to set the page private bit properly
3131 * after the extent buffer is in the radix tree so
3132 * it doesn't get lost
3133 */
3134 set_page_extent_mapped(eb->first_page);
3135 set_page_extent_head(eb->first_page, eb->len);
3136 if (!page0)
3137 unlock_page(eb->first_page);
3138 return eb;
3139
3140free_eb:
3141 if (eb->first_page && !page0)
3142 unlock_page(eb->first_page);
3143
3144 if (!atomic_dec_and_test(&eb->refs))
3145 return exists;
3146 btrfs_release_extent_buffer(eb);
3147 return exists;
3148}
3149
3150struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
3151 u64 start, unsigned long len)
3152{
3153 struct extent_buffer *eb;
3154
3155 rcu_read_lock();
3156 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3157 if (eb && atomic_inc_not_zero(&eb->refs)) {
3158 rcu_read_unlock();
3159 mark_page_accessed(eb->first_page);
3160 return eb;
3161 }
3162 rcu_read_unlock();
3163
3164 return NULL;
3165}
3166
3167void free_extent_buffer(struct extent_buffer *eb)
3168{
3169 if (!eb)
3170 return;
3171
3172 if (!atomic_dec_and_test(&eb->refs))
3173 return;
3174
3175 WARN_ON(1);
3176}
3177
3178int clear_extent_buffer_dirty(struct extent_io_tree *tree,
3179 struct extent_buffer *eb)
3180{
3181 unsigned long i;
3182 unsigned long num_pages;
3183 struct page *page;
3184
3185 num_pages = num_extent_pages(eb->start, eb->len);
3186
3187 for (i = 0; i < num_pages; i++) {
3188 page = extent_buffer_page(eb, i);
3189 if (!PageDirty(page))
3190 continue;
3191
3192 lock_page(page);
3193 WARN_ON(!PagePrivate(page));
3194
3195 set_page_extent_mapped(page);
3196 if (i == 0)
3197 set_page_extent_head(page, eb->len);
3198
3199 clear_page_dirty_for_io(page);
3200 spin_lock_irq(&page->mapping->tree_lock);
3201 if (!PageDirty(page)) {
3202 radix_tree_tag_clear(&page->mapping->page_tree,
3203 page_index(page),
3204 PAGECACHE_TAG_DIRTY);
3205 }
3206 spin_unlock_irq(&page->mapping->tree_lock);
3207 unlock_page(page);
3208 }
3209 return 0;
3210}
3211
3212int set_extent_buffer_dirty(struct extent_io_tree *tree,
3213 struct extent_buffer *eb)
3214{
3215 unsigned long i;
3216 unsigned long num_pages;
3217 int was_dirty = 0;
3218
3219 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
3220 num_pages = num_extent_pages(eb->start, eb->len);
3221 for (i = 0; i < num_pages; i++)
3222 __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3223 return was_dirty;
3224}
3225
3226static int __eb_straddles_pages(u64 start, u64 len)
3227{
3228 if (len < PAGE_CACHE_SIZE)
3229 return 1;
3230 if (start & (PAGE_CACHE_SIZE - 1))
3231 return 1;
3232 if ((start + len) & (PAGE_CACHE_SIZE - 1))
3233 return 1;
3234 return 0;
3235}
3236
3237static int eb_straddles_pages(struct extent_buffer *eb)
3238{
3239 return __eb_straddles_pages(eb->start, eb->len);
3240}
3241
3242int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3243 struct extent_buffer *eb,
3244 struct extent_state **cached_state)
3245{
3246 unsigned long i;
3247 struct page *page;
3248 unsigned long num_pages;
3249
3250 num_pages = num_extent_pages(eb->start, eb->len);
3251 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3252
3253 if (eb_straddles_pages(eb)) {
3254 clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3255 cached_state, GFP_NOFS);
3256 }
3257 for (i = 0; i < num_pages; i++) {
3258 page = extent_buffer_page(eb, i);
3259 if (page)
3260 ClearPageUptodate(page);
3261 }
3262 return 0;
3263}
3264
3265int set_extent_buffer_uptodate(struct extent_io_tree *tree,
3266 struct extent_buffer *eb)
3267{
3268 unsigned long i;
3269 struct page *page;
3270 unsigned long num_pages;
3271
3272 num_pages = num_extent_pages(eb->start, eb->len);
3273
3274 if (eb_straddles_pages(eb)) {
3275 set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3276 NULL, GFP_NOFS);
3277 }
3278 for (i = 0; i < num_pages; i++) {
3279 page = extent_buffer_page(eb, i);
3280 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3281 ((i == num_pages - 1) &&
3282 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3283 check_page_uptodate(tree, page);
3284 continue;
3285 }
3286 SetPageUptodate(page);
3287 }
3288 return 0;
3289}
3290
3291int extent_range_uptodate(struct extent_io_tree *tree,
3292 u64 start, u64 end)
3293{
3294 struct page *page;
3295 int ret;
3296 int pg_uptodate = 1;
3297 int uptodate;
3298 unsigned long index;
3299
3300 if (__eb_straddles_pages(start, end - start + 1)) {
3301 ret = test_range_bit(tree, start, end,
3302 EXTENT_UPTODATE, 1, NULL);
3303 if (ret)
3304 return 1;
3305 }
3306 while (start <= end) {
3307 index = start >> PAGE_CACHE_SHIFT;
3308 page = find_get_page(tree->mapping, index);
3309 uptodate = PageUptodate(page);
3310 page_cache_release(page);
3311 if (!uptodate) {
3312 pg_uptodate = 0;
3313 break;
3314 }
3315 start += PAGE_CACHE_SIZE;
3316 }
3317 return pg_uptodate;
3318}
3319
3320int extent_buffer_uptodate(struct extent_io_tree *tree,
3321 struct extent_buffer *eb,
3322 struct extent_state *cached_state)
3323{
3324 int ret = 0;
3325 unsigned long num_pages;
3326 unsigned long i;
3327 struct page *page;
3328 int pg_uptodate = 1;
3329
3330 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3331 return 1;
3332
3333 if (eb_straddles_pages(eb)) {
3334 ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3335 EXTENT_UPTODATE, 1, cached_state);
3336 if (ret)
3337 return ret;
3338 }
3339
3340 num_pages = num_extent_pages(eb->start, eb->len);
3341 for (i = 0; i < num_pages; i++) {
3342 page = extent_buffer_page(eb, i);
3343 if (!PageUptodate(page)) {
3344 pg_uptodate = 0;
3345 break;
3346 }
3347 }
3348 return pg_uptodate;
3349}
3350
3351int read_extent_buffer_pages(struct extent_io_tree *tree,
3352 struct extent_buffer *eb,
3353 u64 start, int wait,
3354 get_extent_t *get_extent, int mirror_num)
3355{
3356 unsigned long i;
3357 unsigned long start_i;
3358 struct page *page;
3359 int err;
3360 int ret = 0;
3361 int locked_pages = 0;
3362 int all_uptodate = 1;
3363 int inc_all_pages = 0;
3364 unsigned long num_pages;
3365 struct bio *bio = NULL;
3366 unsigned long bio_flags = 0;
3367
3368 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3369 return 0;
3370
3371 if (eb_straddles_pages(eb)) {
3372 if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3373 EXTENT_UPTODATE, 1, NULL)) {
3374 return 0;
3375 }
3376 }
3377
3378 if (start) {
3379 WARN_ON(start < eb->start);
3380 start_i = (start >> PAGE_CACHE_SHIFT) -
3381 (eb->start >> PAGE_CACHE_SHIFT);
3382 } else {
3383 start_i = 0;
3384 }
3385
3386 num_pages = num_extent_pages(eb->start, eb->len);
3387 for (i = start_i; i < num_pages; i++) {
3388 page = extent_buffer_page(eb, i);
3389 if (!wait) {
3390 if (!trylock_page(page))
3391 goto unlock_exit;
3392 } else {
3393 lock_page(page);
3394 }
3395 locked_pages++;
3396 if (!PageUptodate(page))
3397 all_uptodate = 0;
3398 }
3399 if (all_uptodate) {
3400 if (start_i == 0)
3401 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3402 goto unlock_exit;
3403 }
3404
3405 for (i = start_i; i < num_pages; i++) {
3406 page = extent_buffer_page(eb, i);
3407
3408 WARN_ON(!PagePrivate(page));
3409
3410 set_page_extent_mapped(page);
3411 if (i == 0)
3412 set_page_extent_head(page, eb->len);
3413
3414 if (inc_all_pages)
3415 page_cache_get(page);
3416 if (!PageUptodate(page)) {
3417 if (start_i == 0)
3418 inc_all_pages = 1;
3419 ClearPageError(page);
3420 err = __extent_read_full_page(tree, page,
3421 get_extent, &bio,
3422 mirror_num, &bio_flags);
3423 if (err)
3424 ret = err;
3425 } else {
3426 unlock_page(page);
3427 }
3428 }
3429
3430 if (bio)
3431 submit_one_bio(READ, bio, mirror_num, bio_flags);
3432
3433 if (ret || !wait)
3434 return ret;
3435
3436 for (i = start_i; i < num_pages; i++) {
3437 page = extent_buffer_page(eb, i);
3438 wait_on_page_locked(page);
3439 if (!PageUptodate(page))
3440 ret = -EIO;
3441 }
3442
3443 if (!ret)
3444 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3445 return ret;
3446
3447unlock_exit:
3448 i = start_i;
3449 while (locked_pages > 0) {
3450 page = extent_buffer_page(eb, i);
3451 i++;
3452 unlock_page(page);
3453 locked_pages--;
3454 }
3455 return ret;
3456}
3457
3458void read_extent_buffer(struct extent_buffer *eb, void *dstv,
3459 unsigned long start,
3460 unsigned long len)
3461{
3462 size_t cur;
3463 size_t offset;
3464 struct page *page;
3465 char *kaddr;
3466 char *dst = (char *)dstv;
3467 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3468 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3469
3470 WARN_ON(start > eb->len);
3471 WARN_ON(start + len > eb->start + eb->len);
3472
3473 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3474
3475 while (len > 0) {
3476 page = extent_buffer_page(eb, i);
3477
3478 cur = min(len, (PAGE_CACHE_SIZE - offset));
3479 kaddr = page_address(page);
3480 memcpy(dst, kaddr + offset, cur);
3481
3482 dst += cur;
3483 len -= cur;
3484 offset = 0;
3485 i++;
3486 }
3487}
3488
3489int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
3490 unsigned long min_len, char **map,
3491 unsigned long *map_start,
3492 unsigned long *map_len)
3493{
3494 size_t offset = start & (PAGE_CACHE_SIZE - 1);
3495 char *kaddr;
3496 struct page *p;
3497 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3498 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3499 unsigned long end_i = (start_offset + start + min_len - 1) >>
3500 PAGE_CACHE_SHIFT;
3501
3502 if (i != end_i)
3503 return -EINVAL;
3504
3505 if (i == 0) {
3506 offset = start_offset;
3507 *map_start = 0;
3508 } else {
3509 offset = 0;
3510 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
3511 }
3512
3513 if (start + min_len > eb->len) {
3514 printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
3515 "wanted %lu %lu\n", (unsigned long long)eb->start,
3516 eb->len, start, min_len);
3517 WARN_ON(1);
3518 return -EINVAL;
3519 }
3520
3521 p = extent_buffer_page(eb, i);
3522 kaddr = page_address(p);
3523 *map = kaddr + offset;
3524 *map_len = PAGE_CACHE_SIZE - offset;
3525 return 0;
3526}
3527
3528int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
3529 unsigned long start,
3530 unsigned long len)
3531{
3532 size_t cur;
3533 size_t offset;
3534 struct page *page;
3535 char *kaddr;
3536 char *ptr = (char *)ptrv;
3537 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3538 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3539 int ret = 0;
3540
3541 WARN_ON(start > eb->len);
3542 WARN_ON(start + len > eb->start + eb->len);
3543
3544 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3545
3546 while (len > 0) {
3547 page = extent_buffer_page(eb, i);
3548
3549 cur = min(len, (PAGE_CACHE_SIZE - offset));
3550
3551 kaddr = page_address(page);
3552 ret = memcmp(ptr, kaddr + offset, cur);
3553 if (ret)
3554 break;
3555
3556 ptr += cur;
3557 len -= cur;
3558 offset = 0;
3559 i++;
3560 }
3561 return ret;
3562}
3563
3564void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
3565 unsigned long start, unsigned long len)
3566{
3567 size_t cur;
3568 size_t offset;
3569 struct page *page;
3570 char *kaddr;
3571 char *src = (char *)srcv;
3572 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3573 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3574
3575 WARN_ON(start > eb->len);
3576 WARN_ON(start + len > eb->start + eb->len);
3577
3578 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3579
3580 while (len > 0) {
3581 page = extent_buffer_page(eb, i);
3582 WARN_ON(!PageUptodate(page));
3583
3584 cur = min(len, PAGE_CACHE_SIZE - offset);
3585 kaddr = page_address(page);
3586 memcpy(kaddr + offset, src, cur);
3587
3588 src += cur;
3589 len -= cur;
3590 offset = 0;
3591 i++;
3592 }
3593}
3594
3595void memset_extent_buffer(struct extent_buffer *eb, char c,
3596 unsigned long start, unsigned long len)
3597{
3598 size_t cur;
3599 size_t offset;
3600 struct page *page;
3601 char *kaddr;
3602 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3603 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3604
3605 WARN_ON(start > eb->len);
3606 WARN_ON(start + len > eb->start + eb->len);
3607
3608 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3609
3610 while (len > 0) {
3611 page = extent_buffer_page(eb, i);
3612 WARN_ON(!PageUptodate(page));
3613
3614 cur = min(len, PAGE_CACHE_SIZE - offset);
3615 kaddr = page_address(page);
3616 memset(kaddr + offset, c, cur);
3617
3618 len -= cur;
3619 offset = 0;
3620 i++;
3621 }
3622}
3623
3624void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
3625 unsigned long dst_offset, unsigned long src_offset,
3626 unsigned long len)
3627{
3628 u64 dst_len = dst->len;
3629 size_t cur;
3630 size_t offset;
3631 struct page *page;
3632 char *kaddr;
3633 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3634 unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3635
3636 WARN_ON(src->len != dst_len);
3637
3638 offset = (start_offset + dst_offset) &
3639 ((unsigned long)PAGE_CACHE_SIZE - 1);
3640
3641 while (len > 0) {
3642 page = extent_buffer_page(dst, i);
3643 WARN_ON(!PageUptodate(page));
3644
3645 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
3646
3647 kaddr = page_address(page);
3648 read_extent_buffer(src, kaddr + offset, src_offset, cur);
3649
3650 src_offset += cur;
3651 len -= cur;
3652 offset = 0;
3653 i++;
3654 }
3655}
3656
3657static void move_pages(struct page *dst_page, struct page *src_page,
3658 unsigned long dst_off, unsigned long src_off,
3659 unsigned long len)
3660{
3661 char *dst_kaddr = page_address(dst_page);
3662 if (dst_page == src_page) {
3663 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
3664 } else {
3665 char *src_kaddr = page_address(src_page);
3666 char *p = dst_kaddr + dst_off + len;
3667 char *s = src_kaddr + src_off + len;
3668
3669 while (len--)
3670 *--p = *--s;
3671 }
3672}
3673
3674static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
3675{
3676 unsigned long distance = (src > dst) ? src - dst : dst - src;
3677 return distance < len;
3678}
3679
3680static void copy_pages(struct page *dst_page, struct page *src_page,
3681 unsigned long dst_off, unsigned long src_off,
3682 unsigned long len)
3683{
3684 char *dst_kaddr = page_address(dst_page);
3685 char *src_kaddr;
3686
3687 if (dst_page != src_page) {
3688 src_kaddr = page_address(src_page);
3689 } else {
3690 src_kaddr = dst_kaddr;
3691 BUG_ON(areas_overlap(src_off, dst_off, len));
3692 }
3693
3694 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
3695}
3696
3697void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3698 unsigned long src_offset, unsigned long len)
3699{
3700 size_t cur;
3701 size_t dst_off_in_page;
3702 size_t src_off_in_page;
3703 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3704 unsigned long dst_i;
3705 unsigned long src_i;
3706
3707 if (src_offset + len > dst->len) {
3708 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3709 "len %lu dst len %lu\n", src_offset, len, dst->len);
3710 BUG_ON(1);
3711 }
3712 if (dst_offset + len > dst->len) {
3713 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3714 "len %lu dst len %lu\n", dst_offset, len, dst->len);
3715 BUG_ON(1);
3716 }
3717
3718 while (len > 0) {
3719 dst_off_in_page = (start_offset + dst_offset) &
3720 ((unsigned long)PAGE_CACHE_SIZE - 1);
3721 src_off_in_page = (start_offset + src_offset) &
3722 ((unsigned long)PAGE_CACHE_SIZE - 1);
3723
3724 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3725 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
3726
3727 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
3728 src_off_in_page));
3729 cur = min_t(unsigned long, cur,
3730 (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
3731
3732 copy_pages(extent_buffer_page(dst, dst_i),
3733 extent_buffer_page(dst, src_i),
3734 dst_off_in_page, src_off_in_page, cur);
3735
3736 src_offset += cur;
3737 dst_offset += cur;
3738 len -= cur;
3739 }
3740}
3741
3742void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3743 unsigned long src_offset, unsigned long len)
3744{
3745 size_t cur;
3746 size_t dst_off_in_page;
3747 size_t src_off_in_page;
3748 unsigned long dst_end = dst_offset + len - 1;
3749 unsigned long src_end = src_offset + len - 1;
3750 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3751 unsigned long dst_i;
3752 unsigned long src_i;
3753
3754 if (src_offset + len > dst->len) {
3755 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3756 "len %lu len %lu\n", src_offset, len, dst->len);
3757 BUG_ON(1);
3758 }
3759 if (dst_offset + len > dst->len) {
3760 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3761 "len %lu len %lu\n", dst_offset, len, dst->len);
3762 BUG_ON(1);
3763 }
3764 if (!areas_overlap(src_offset, dst_offset, len)) {
3765 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
3766 return;
3767 }
3768 while (len > 0) {
3769 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
3770 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
3771
3772 dst_off_in_page = (start_offset + dst_end) &
3773 ((unsigned long)PAGE_CACHE_SIZE - 1);
3774 src_off_in_page = (start_offset + src_end) &
3775 ((unsigned long)PAGE_CACHE_SIZE - 1);
3776
3777 cur = min_t(unsigned long, len, src_off_in_page + 1);
3778 cur = min(cur, dst_off_in_page + 1);
3779 move_pages(extent_buffer_page(dst, dst_i),
3780 extent_buffer_page(dst, src_i),
3781 dst_off_in_page - cur + 1,
3782 src_off_in_page - cur + 1, cur);
3783
3784 dst_end -= cur;
3785 src_end -= cur;
3786 len -= cur;
3787 }
3788}
3789
3790static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
3791{
3792 struct extent_buffer *eb =
3793 container_of(head, struct extent_buffer, rcu_head);
3794
3795 btrfs_release_extent_buffer(eb);
3796}
3797
3798int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
3799{
3800 u64 start = page_offset(page);
3801 struct extent_buffer *eb;
3802 int ret = 1;
3803
3804 spin_lock(&tree->buffer_lock);
3805 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3806 if (!eb) {
3807 spin_unlock(&tree->buffer_lock);
3808 return ret;
3809 }
3810
3811 if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3812 ret = 0;
3813 goto out;
3814 }
3815
3816 /*
3817 * set @eb->refs to 0 if it is already 1, and then release the @eb.
3818 * Or go back.
3819 */
3820 if (atomic_cmpxchg(&eb->refs, 1, 0) != 1) {
3821 ret = 0;
3822 goto out;
3823 }
3824
3825 radix_tree_delete(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3826out:
3827 spin_unlock(&tree->buffer_lock);
3828
3829 /* at this point we can safely release the extent buffer */
3830 if (atomic_read(&eb->refs) == 0)
3831 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
3832 return ret;
3833}
1#include <linux/bitops.h>
2#include <linux/slab.h>
3#include <linux/bio.h>
4#include <linux/mm.h>
5#include <linux/pagemap.h>
6#include <linux/page-flags.h>
7#include <linux/spinlock.h>
8#include <linux/blkdev.h>
9#include <linux/swap.h>
10#include <linux/writeback.h>
11#include <linux/pagevec.h>
12#include <linux/prefetch.h>
13#include <linux/cleancache.h>
14#include "extent_io.h"
15#include "extent_map.h"
16#include "ctree.h"
17#include "btrfs_inode.h"
18#include "volumes.h"
19#include "check-integrity.h"
20#include "locking.h"
21#include "rcu-string.h"
22#include "backref.h"
23#include "transaction.h"
24
25static struct kmem_cache *extent_state_cache;
26static struct kmem_cache *extent_buffer_cache;
27static struct bio_set *btrfs_bioset;
28
29static inline bool extent_state_in_tree(const struct extent_state *state)
30{
31 return !RB_EMPTY_NODE(&state->rb_node);
32}
33
34#ifdef CONFIG_BTRFS_DEBUG
35static LIST_HEAD(buffers);
36static LIST_HEAD(states);
37
38static DEFINE_SPINLOCK(leak_lock);
39
40static inline
41void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
42{
43 unsigned long flags;
44
45 spin_lock_irqsave(&leak_lock, flags);
46 list_add(new, head);
47 spin_unlock_irqrestore(&leak_lock, flags);
48}
49
50static inline
51void btrfs_leak_debug_del(struct list_head *entry)
52{
53 unsigned long flags;
54
55 spin_lock_irqsave(&leak_lock, flags);
56 list_del(entry);
57 spin_unlock_irqrestore(&leak_lock, flags);
58}
59
60static inline
61void btrfs_leak_debug_check(void)
62{
63 struct extent_state *state;
64 struct extent_buffer *eb;
65
66 while (!list_empty(&states)) {
67 state = list_entry(states.next, struct extent_state, leak_list);
68 pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
69 state->start, state->end, state->state,
70 extent_state_in_tree(state),
71 atomic_read(&state->refs));
72 list_del(&state->leak_list);
73 kmem_cache_free(extent_state_cache, state);
74 }
75
76 while (!list_empty(&buffers)) {
77 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
78 pr_err("BTRFS: buffer leak start %llu len %lu refs %d\n",
79 eb->start, eb->len, atomic_read(&eb->refs));
80 list_del(&eb->leak_list);
81 kmem_cache_free(extent_buffer_cache, eb);
82 }
83}
84
85#define btrfs_debug_check_extent_io_range(tree, start, end) \
86 __btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
87static inline void __btrfs_debug_check_extent_io_range(const char *caller,
88 struct extent_io_tree *tree, u64 start, u64 end)
89{
90 struct inode *inode;
91 u64 isize;
92
93 if (!tree->mapping)
94 return;
95
96 inode = tree->mapping->host;
97 isize = i_size_read(inode);
98 if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
99 btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
100 "%s: ino %llu isize %llu odd range [%llu,%llu]",
101 caller, btrfs_ino(inode), isize, start, end);
102 }
103}
104#else
105#define btrfs_leak_debug_add(new, head) do {} while (0)
106#define btrfs_leak_debug_del(entry) do {} while (0)
107#define btrfs_leak_debug_check() do {} while (0)
108#define btrfs_debug_check_extent_io_range(c, s, e) do {} while (0)
109#endif
110
111#define BUFFER_LRU_MAX 64
112
113struct tree_entry {
114 u64 start;
115 u64 end;
116 struct rb_node rb_node;
117};
118
119struct extent_page_data {
120 struct bio *bio;
121 struct extent_io_tree *tree;
122 get_extent_t *get_extent;
123 unsigned long bio_flags;
124
125 /* tells writepage not to lock the state bits for this range
126 * it still does the unlocking
127 */
128 unsigned int extent_locked:1;
129
130 /* tells the submit_bio code to use REQ_SYNC */
131 unsigned int sync_io:1;
132};
133
134static void add_extent_changeset(struct extent_state *state, unsigned bits,
135 struct extent_changeset *changeset,
136 int set)
137{
138 int ret;
139
140 if (!changeset)
141 return;
142 if (set && (state->state & bits) == bits)
143 return;
144 if (!set && (state->state & bits) == 0)
145 return;
146 changeset->bytes_changed += state->end - state->start + 1;
147 ret = ulist_add(changeset->range_changed, state->start, state->end,
148 GFP_ATOMIC);
149 /* ENOMEM */
150 BUG_ON(ret < 0);
151}
152
153static noinline void flush_write_bio(void *data);
154static inline struct btrfs_fs_info *
155tree_fs_info(struct extent_io_tree *tree)
156{
157 if (!tree->mapping)
158 return NULL;
159 return btrfs_sb(tree->mapping->host->i_sb);
160}
161
162int __init extent_io_init(void)
163{
164 extent_state_cache = kmem_cache_create("btrfs_extent_state",
165 sizeof(struct extent_state), 0,
166 SLAB_MEM_SPREAD, NULL);
167 if (!extent_state_cache)
168 return -ENOMEM;
169
170 extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
171 sizeof(struct extent_buffer), 0,
172 SLAB_MEM_SPREAD, NULL);
173 if (!extent_buffer_cache)
174 goto free_state_cache;
175
176 btrfs_bioset = bioset_create(BIO_POOL_SIZE,
177 offsetof(struct btrfs_io_bio, bio));
178 if (!btrfs_bioset)
179 goto free_buffer_cache;
180
181 if (bioset_integrity_create(btrfs_bioset, BIO_POOL_SIZE))
182 goto free_bioset;
183
184 return 0;
185
186free_bioset:
187 bioset_free(btrfs_bioset);
188 btrfs_bioset = NULL;
189
190free_buffer_cache:
191 kmem_cache_destroy(extent_buffer_cache);
192 extent_buffer_cache = NULL;
193
194free_state_cache:
195 kmem_cache_destroy(extent_state_cache);
196 extent_state_cache = NULL;
197 return -ENOMEM;
198}
199
200void extent_io_exit(void)
201{
202 btrfs_leak_debug_check();
203
204 /*
205 * Make sure all delayed rcu free are flushed before we
206 * destroy caches.
207 */
208 rcu_barrier();
209 kmem_cache_destroy(extent_state_cache);
210 kmem_cache_destroy(extent_buffer_cache);
211 if (btrfs_bioset)
212 bioset_free(btrfs_bioset);
213}
214
215void extent_io_tree_init(struct extent_io_tree *tree,
216 struct address_space *mapping)
217{
218 tree->state = RB_ROOT;
219 tree->ops = NULL;
220 tree->dirty_bytes = 0;
221 spin_lock_init(&tree->lock);
222 tree->mapping = mapping;
223}
224
225static struct extent_state *alloc_extent_state(gfp_t mask)
226{
227 struct extent_state *state;
228
229 state = kmem_cache_alloc(extent_state_cache, mask);
230 if (!state)
231 return state;
232 state->state = 0;
233 state->failrec = NULL;
234 RB_CLEAR_NODE(&state->rb_node);
235 btrfs_leak_debug_add(&state->leak_list, &states);
236 atomic_set(&state->refs, 1);
237 init_waitqueue_head(&state->wq);
238 trace_alloc_extent_state(state, mask, _RET_IP_);
239 return state;
240}
241
242void free_extent_state(struct extent_state *state)
243{
244 if (!state)
245 return;
246 if (atomic_dec_and_test(&state->refs)) {
247 WARN_ON(extent_state_in_tree(state));
248 btrfs_leak_debug_del(&state->leak_list);
249 trace_free_extent_state(state, _RET_IP_);
250 kmem_cache_free(extent_state_cache, state);
251 }
252}
253
254static struct rb_node *tree_insert(struct rb_root *root,
255 struct rb_node *search_start,
256 u64 offset,
257 struct rb_node *node,
258 struct rb_node ***p_in,
259 struct rb_node **parent_in)
260{
261 struct rb_node **p;
262 struct rb_node *parent = NULL;
263 struct tree_entry *entry;
264
265 if (p_in && parent_in) {
266 p = *p_in;
267 parent = *parent_in;
268 goto do_insert;
269 }
270
271 p = search_start ? &search_start : &root->rb_node;
272 while (*p) {
273 parent = *p;
274 entry = rb_entry(parent, struct tree_entry, rb_node);
275
276 if (offset < entry->start)
277 p = &(*p)->rb_left;
278 else if (offset > entry->end)
279 p = &(*p)->rb_right;
280 else
281 return parent;
282 }
283
284do_insert:
285 rb_link_node(node, parent, p);
286 rb_insert_color(node, root);
287 return NULL;
288}
289
290static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
291 struct rb_node **prev_ret,
292 struct rb_node **next_ret,
293 struct rb_node ***p_ret,
294 struct rb_node **parent_ret)
295{
296 struct rb_root *root = &tree->state;
297 struct rb_node **n = &root->rb_node;
298 struct rb_node *prev = NULL;
299 struct rb_node *orig_prev = NULL;
300 struct tree_entry *entry;
301 struct tree_entry *prev_entry = NULL;
302
303 while (*n) {
304 prev = *n;
305 entry = rb_entry(prev, struct tree_entry, rb_node);
306 prev_entry = entry;
307
308 if (offset < entry->start)
309 n = &(*n)->rb_left;
310 else if (offset > entry->end)
311 n = &(*n)->rb_right;
312 else
313 return *n;
314 }
315
316 if (p_ret)
317 *p_ret = n;
318 if (parent_ret)
319 *parent_ret = prev;
320
321 if (prev_ret) {
322 orig_prev = prev;
323 while (prev && offset > prev_entry->end) {
324 prev = rb_next(prev);
325 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
326 }
327 *prev_ret = prev;
328 prev = orig_prev;
329 }
330
331 if (next_ret) {
332 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
333 while (prev && offset < prev_entry->start) {
334 prev = rb_prev(prev);
335 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
336 }
337 *next_ret = prev;
338 }
339 return NULL;
340}
341
342static inline struct rb_node *
343tree_search_for_insert(struct extent_io_tree *tree,
344 u64 offset,
345 struct rb_node ***p_ret,
346 struct rb_node **parent_ret)
347{
348 struct rb_node *prev = NULL;
349 struct rb_node *ret;
350
351 ret = __etree_search(tree, offset, &prev, NULL, p_ret, parent_ret);
352 if (!ret)
353 return prev;
354 return ret;
355}
356
357static inline struct rb_node *tree_search(struct extent_io_tree *tree,
358 u64 offset)
359{
360 return tree_search_for_insert(tree, offset, NULL, NULL);
361}
362
363static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
364 struct extent_state *other)
365{
366 if (tree->ops && tree->ops->merge_extent_hook)
367 tree->ops->merge_extent_hook(tree->mapping->host, new,
368 other);
369}
370
371/*
372 * utility function to look for merge candidates inside a given range.
373 * Any extents with matching state are merged together into a single
374 * extent in the tree. Extents with EXTENT_IO in their state field
375 * are not merged because the end_io handlers need to be able to do
376 * operations on them without sleeping (or doing allocations/splits).
377 *
378 * This should be called with the tree lock held.
379 */
380static void merge_state(struct extent_io_tree *tree,
381 struct extent_state *state)
382{
383 struct extent_state *other;
384 struct rb_node *other_node;
385
386 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
387 return;
388
389 other_node = rb_prev(&state->rb_node);
390 if (other_node) {
391 other = rb_entry(other_node, struct extent_state, rb_node);
392 if (other->end == state->start - 1 &&
393 other->state == state->state) {
394 merge_cb(tree, state, other);
395 state->start = other->start;
396 rb_erase(&other->rb_node, &tree->state);
397 RB_CLEAR_NODE(&other->rb_node);
398 free_extent_state(other);
399 }
400 }
401 other_node = rb_next(&state->rb_node);
402 if (other_node) {
403 other = rb_entry(other_node, struct extent_state, rb_node);
404 if (other->start == state->end + 1 &&
405 other->state == state->state) {
406 merge_cb(tree, state, other);
407 state->end = other->end;
408 rb_erase(&other->rb_node, &tree->state);
409 RB_CLEAR_NODE(&other->rb_node);
410 free_extent_state(other);
411 }
412 }
413}
414
415static void set_state_cb(struct extent_io_tree *tree,
416 struct extent_state *state, unsigned *bits)
417{
418 if (tree->ops && tree->ops->set_bit_hook)
419 tree->ops->set_bit_hook(tree->mapping->host, state, bits);
420}
421
422static void clear_state_cb(struct extent_io_tree *tree,
423 struct extent_state *state, unsigned *bits)
424{
425 if (tree->ops && tree->ops->clear_bit_hook)
426 tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
427}
428
429static void set_state_bits(struct extent_io_tree *tree,
430 struct extent_state *state, unsigned *bits,
431 struct extent_changeset *changeset);
432
433/*
434 * insert an extent_state struct into the tree. 'bits' are set on the
435 * struct before it is inserted.
436 *
437 * This may return -EEXIST if the extent is already there, in which case the
438 * state struct is freed.
439 *
440 * The tree lock is not taken internally. This is a utility function and
441 * probably isn't what you want to call (see set/clear_extent_bit).
442 */
443static int insert_state(struct extent_io_tree *tree,
444 struct extent_state *state, u64 start, u64 end,
445 struct rb_node ***p,
446 struct rb_node **parent,
447 unsigned *bits, struct extent_changeset *changeset)
448{
449 struct rb_node *node;
450
451 if (end < start)
452 WARN(1, KERN_ERR "BTRFS: end < start %llu %llu\n",
453 end, start);
454 state->start = start;
455 state->end = end;
456
457 set_state_bits(tree, state, bits, changeset);
458
459 node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
460 if (node) {
461 struct extent_state *found;
462 found = rb_entry(node, struct extent_state, rb_node);
463 pr_err("BTRFS: found node %llu %llu on insert of %llu %llu\n",
464 found->start, found->end, start, end);
465 return -EEXIST;
466 }
467 merge_state(tree, state);
468 return 0;
469}
470
471static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
472 u64 split)
473{
474 if (tree->ops && tree->ops->split_extent_hook)
475 tree->ops->split_extent_hook(tree->mapping->host, orig, split);
476}
477
478/*
479 * split a given extent state struct in two, inserting the preallocated
480 * struct 'prealloc' as the newly created second half. 'split' indicates an
481 * offset inside 'orig' where it should be split.
482 *
483 * Before calling,
484 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
485 * are two extent state structs in the tree:
486 * prealloc: [orig->start, split - 1]
487 * orig: [ split, orig->end ]
488 *
489 * The tree locks are not taken by this function. They need to be held
490 * by the caller.
491 */
492static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
493 struct extent_state *prealloc, u64 split)
494{
495 struct rb_node *node;
496
497 split_cb(tree, orig, split);
498
499 prealloc->start = orig->start;
500 prealloc->end = split - 1;
501 prealloc->state = orig->state;
502 orig->start = split;
503
504 node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
505 &prealloc->rb_node, NULL, NULL);
506 if (node) {
507 free_extent_state(prealloc);
508 return -EEXIST;
509 }
510 return 0;
511}
512
513static struct extent_state *next_state(struct extent_state *state)
514{
515 struct rb_node *next = rb_next(&state->rb_node);
516 if (next)
517 return rb_entry(next, struct extent_state, rb_node);
518 else
519 return NULL;
520}
521
522/*
523 * utility function to clear some bits in an extent state struct.
524 * it will optionally wake up any one waiting on this state (wake == 1).
525 *
526 * If no bits are set on the state struct after clearing things, the
527 * struct is freed and removed from the tree
528 */
529static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
530 struct extent_state *state,
531 unsigned *bits, int wake,
532 struct extent_changeset *changeset)
533{
534 struct extent_state *next;
535 unsigned bits_to_clear = *bits & ~EXTENT_CTLBITS;
536
537 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
538 u64 range = state->end - state->start + 1;
539 WARN_ON(range > tree->dirty_bytes);
540 tree->dirty_bytes -= range;
541 }
542 clear_state_cb(tree, state, bits);
543 add_extent_changeset(state, bits_to_clear, changeset, 0);
544 state->state &= ~bits_to_clear;
545 if (wake)
546 wake_up(&state->wq);
547 if (state->state == 0) {
548 next = next_state(state);
549 if (extent_state_in_tree(state)) {
550 rb_erase(&state->rb_node, &tree->state);
551 RB_CLEAR_NODE(&state->rb_node);
552 free_extent_state(state);
553 } else {
554 WARN_ON(1);
555 }
556 } else {
557 merge_state(tree, state);
558 next = next_state(state);
559 }
560 return next;
561}
562
563static struct extent_state *
564alloc_extent_state_atomic(struct extent_state *prealloc)
565{
566 if (!prealloc)
567 prealloc = alloc_extent_state(GFP_ATOMIC);
568
569 return prealloc;
570}
571
572static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
573{
574 btrfs_panic(tree_fs_info(tree), err,
575 "Locking error: Extent tree was modified by another thread while locked.");
576}
577
578/*
579 * clear some bits on a range in the tree. This may require splitting
580 * or inserting elements in the tree, so the gfp mask is used to
581 * indicate which allocations or sleeping are allowed.
582 *
583 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
584 * the given range from the tree regardless of state (ie for truncate).
585 *
586 * the range [start, end] is inclusive.
587 *
588 * This takes the tree lock, and returns 0 on success and < 0 on error.
589 */
590static int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
591 unsigned bits, int wake, int delete,
592 struct extent_state **cached_state,
593 gfp_t mask, struct extent_changeset *changeset)
594{
595 struct extent_state *state;
596 struct extent_state *cached;
597 struct extent_state *prealloc = NULL;
598 struct rb_node *node;
599 u64 last_end;
600 int err;
601 int clear = 0;
602
603 btrfs_debug_check_extent_io_range(tree, start, end);
604
605 if (bits & EXTENT_DELALLOC)
606 bits |= EXTENT_NORESERVE;
607
608 if (delete)
609 bits |= ~EXTENT_CTLBITS;
610 bits |= EXTENT_FIRST_DELALLOC;
611
612 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
613 clear = 1;
614again:
615 if (!prealloc && gfpflags_allow_blocking(mask)) {
616 /*
617 * Don't care for allocation failure here because we might end
618 * up not needing the pre-allocated extent state at all, which
619 * is the case if we only have in the tree extent states that
620 * cover our input range and don't cover too any other range.
621 * If we end up needing a new extent state we allocate it later.
622 */
623 prealloc = alloc_extent_state(mask);
624 }
625
626 spin_lock(&tree->lock);
627 if (cached_state) {
628 cached = *cached_state;
629
630 if (clear) {
631 *cached_state = NULL;
632 cached_state = NULL;
633 }
634
635 if (cached && extent_state_in_tree(cached) &&
636 cached->start <= start && cached->end > start) {
637 if (clear)
638 atomic_dec(&cached->refs);
639 state = cached;
640 goto hit_next;
641 }
642 if (clear)
643 free_extent_state(cached);
644 }
645 /*
646 * this search will find the extents that end after
647 * our range starts
648 */
649 node = tree_search(tree, start);
650 if (!node)
651 goto out;
652 state = rb_entry(node, struct extent_state, rb_node);
653hit_next:
654 if (state->start > end)
655 goto out;
656 WARN_ON(state->end < start);
657 last_end = state->end;
658
659 /* the state doesn't have the wanted bits, go ahead */
660 if (!(state->state & bits)) {
661 state = next_state(state);
662 goto next;
663 }
664
665 /*
666 * | ---- desired range ---- |
667 * | state | or
668 * | ------------- state -------------- |
669 *
670 * We need to split the extent we found, and may flip
671 * bits on second half.
672 *
673 * If the extent we found extends past our range, we
674 * just split and search again. It'll get split again
675 * the next time though.
676 *
677 * If the extent we found is inside our range, we clear
678 * the desired bit on it.
679 */
680
681 if (state->start < start) {
682 prealloc = alloc_extent_state_atomic(prealloc);
683 BUG_ON(!prealloc);
684 err = split_state(tree, state, prealloc, start);
685 if (err)
686 extent_io_tree_panic(tree, err);
687
688 prealloc = NULL;
689 if (err)
690 goto out;
691 if (state->end <= end) {
692 state = clear_state_bit(tree, state, &bits, wake,
693 changeset);
694 goto next;
695 }
696 goto search_again;
697 }
698 /*
699 * | ---- desired range ---- |
700 * | state |
701 * We need to split the extent, and clear the bit
702 * on the first half
703 */
704 if (state->start <= end && state->end > end) {
705 prealloc = alloc_extent_state_atomic(prealloc);
706 BUG_ON(!prealloc);
707 err = split_state(tree, state, prealloc, end + 1);
708 if (err)
709 extent_io_tree_panic(tree, err);
710
711 if (wake)
712 wake_up(&state->wq);
713
714 clear_state_bit(tree, prealloc, &bits, wake, changeset);
715
716 prealloc = NULL;
717 goto out;
718 }
719
720 state = clear_state_bit(tree, state, &bits, wake, changeset);
721next:
722 if (last_end == (u64)-1)
723 goto out;
724 start = last_end + 1;
725 if (start <= end && state && !need_resched())
726 goto hit_next;
727
728search_again:
729 if (start > end)
730 goto out;
731 spin_unlock(&tree->lock);
732 if (gfpflags_allow_blocking(mask))
733 cond_resched();
734 goto again;
735
736out:
737 spin_unlock(&tree->lock);
738 if (prealloc)
739 free_extent_state(prealloc);
740
741 return 0;
742
743}
744
745static void wait_on_state(struct extent_io_tree *tree,
746 struct extent_state *state)
747 __releases(tree->lock)
748 __acquires(tree->lock)
749{
750 DEFINE_WAIT(wait);
751 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
752 spin_unlock(&tree->lock);
753 schedule();
754 spin_lock(&tree->lock);
755 finish_wait(&state->wq, &wait);
756}
757
758/*
759 * waits for one or more bits to clear on a range in the state tree.
760 * The range [start, end] is inclusive.
761 * The tree lock is taken by this function
762 */
763static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
764 unsigned long bits)
765{
766 struct extent_state *state;
767 struct rb_node *node;
768
769 btrfs_debug_check_extent_io_range(tree, start, end);
770
771 spin_lock(&tree->lock);
772again:
773 while (1) {
774 /*
775 * this search will find all the extents that end after
776 * our range starts
777 */
778 node = tree_search(tree, start);
779process_node:
780 if (!node)
781 break;
782
783 state = rb_entry(node, struct extent_state, rb_node);
784
785 if (state->start > end)
786 goto out;
787
788 if (state->state & bits) {
789 start = state->start;
790 atomic_inc(&state->refs);
791 wait_on_state(tree, state);
792 free_extent_state(state);
793 goto again;
794 }
795 start = state->end + 1;
796
797 if (start > end)
798 break;
799
800 if (!cond_resched_lock(&tree->lock)) {
801 node = rb_next(node);
802 goto process_node;
803 }
804 }
805out:
806 spin_unlock(&tree->lock);
807}
808
809static void set_state_bits(struct extent_io_tree *tree,
810 struct extent_state *state,
811 unsigned *bits, struct extent_changeset *changeset)
812{
813 unsigned bits_to_set = *bits & ~EXTENT_CTLBITS;
814
815 set_state_cb(tree, state, bits);
816 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
817 u64 range = state->end - state->start + 1;
818 tree->dirty_bytes += range;
819 }
820 add_extent_changeset(state, bits_to_set, changeset, 1);
821 state->state |= bits_to_set;
822}
823
824static void cache_state_if_flags(struct extent_state *state,
825 struct extent_state **cached_ptr,
826 unsigned flags)
827{
828 if (cached_ptr && !(*cached_ptr)) {
829 if (!flags || (state->state & flags)) {
830 *cached_ptr = state;
831 atomic_inc(&state->refs);
832 }
833 }
834}
835
836static void cache_state(struct extent_state *state,
837 struct extent_state **cached_ptr)
838{
839 return cache_state_if_flags(state, cached_ptr,
840 EXTENT_IOBITS | EXTENT_BOUNDARY);
841}
842
843/*
844 * set some bits on a range in the tree. This may require allocations or
845 * sleeping, so the gfp mask is used to indicate what is allowed.
846 *
847 * If any of the exclusive bits are set, this will fail with -EEXIST if some
848 * part of the range already has the desired bits set. The start of the
849 * existing range is returned in failed_start in this case.
850 *
851 * [start, end] is inclusive This takes the tree lock.
852 */
853
854static int __must_check
855__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
856 unsigned bits, unsigned exclusive_bits,
857 u64 *failed_start, struct extent_state **cached_state,
858 gfp_t mask, struct extent_changeset *changeset)
859{
860 struct extent_state *state;
861 struct extent_state *prealloc = NULL;
862 struct rb_node *node;
863 struct rb_node **p;
864 struct rb_node *parent;
865 int err = 0;
866 u64 last_start;
867 u64 last_end;
868
869 btrfs_debug_check_extent_io_range(tree, start, end);
870
871 bits |= EXTENT_FIRST_DELALLOC;
872again:
873 if (!prealloc && gfpflags_allow_blocking(mask)) {
874 /*
875 * Don't care for allocation failure here because we might end
876 * up not needing the pre-allocated extent state at all, which
877 * is the case if we only have in the tree extent states that
878 * cover our input range and don't cover too any other range.
879 * If we end up needing a new extent state we allocate it later.
880 */
881 prealloc = alloc_extent_state(mask);
882 }
883
884 spin_lock(&tree->lock);
885 if (cached_state && *cached_state) {
886 state = *cached_state;
887 if (state->start <= start && state->end > start &&
888 extent_state_in_tree(state)) {
889 node = &state->rb_node;
890 goto hit_next;
891 }
892 }
893 /*
894 * this search will find all the extents that end after
895 * our range starts.
896 */
897 node = tree_search_for_insert(tree, start, &p, &parent);
898 if (!node) {
899 prealloc = alloc_extent_state_atomic(prealloc);
900 BUG_ON(!prealloc);
901 err = insert_state(tree, prealloc, start, end,
902 &p, &parent, &bits, changeset);
903 if (err)
904 extent_io_tree_panic(tree, err);
905
906 cache_state(prealloc, cached_state);
907 prealloc = NULL;
908 goto out;
909 }
910 state = rb_entry(node, struct extent_state, rb_node);
911hit_next:
912 last_start = state->start;
913 last_end = state->end;
914
915 /*
916 * | ---- desired range ---- |
917 * | state |
918 *
919 * Just lock what we found and keep going
920 */
921 if (state->start == start && state->end <= end) {
922 if (state->state & exclusive_bits) {
923 *failed_start = state->start;
924 err = -EEXIST;
925 goto out;
926 }
927
928 set_state_bits(tree, state, &bits, changeset);
929 cache_state(state, cached_state);
930 merge_state(tree, state);
931 if (last_end == (u64)-1)
932 goto out;
933 start = last_end + 1;
934 state = next_state(state);
935 if (start < end && state && state->start == start &&
936 !need_resched())
937 goto hit_next;
938 goto search_again;
939 }
940
941 /*
942 * | ---- desired range ---- |
943 * | state |
944 * or
945 * | ------------- state -------------- |
946 *
947 * We need to split the extent we found, and may flip bits on
948 * second half.
949 *
950 * If the extent we found extends past our
951 * range, we just split and search again. It'll get split
952 * again the next time though.
953 *
954 * If the extent we found is inside our range, we set the
955 * desired bit on it.
956 */
957 if (state->start < start) {
958 if (state->state & exclusive_bits) {
959 *failed_start = start;
960 err = -EEXIST;
961 goto out;
962 }
963
964 prealloc = alloc_extent_state_atomic(prealloc);
965 BUG_ON(!prealloc);
966 err = split_state(tree, state, prealloc, start);
967 if (err)
968 extent_io_tree_panic(tree, err);
969
970 prealloc = NULL;
971 if (err)
972 goto out;
973 if (state->end <= end) {
974 set_state_bits(tree, state, &bits, changeset);
975 cache_state(state, cached_state);
976 merge_state(tree, state);
977 if (last_end == (u64)-1)
978 goto out;
979 start = last_end + 1;
980 state = next_state(state);
981 if (start < end && state && state->start == start &&
982 !need_resched())
983 goto hit_next;
984 }
985 goto search_again;
986 }
987 /*
988 * | ---- desired range ---- |
989 * | state | or | state |
990 *
991 * There's a hole, we need to insert something in it and
992 * ignore the extent we found.
993 */
994 if (state->start > start) {
995 u64 this_end;
996 if (end < last_start)
997 this_end = end;
998 else
999 this_end = last_start - 1;
1000
1001 prealloc = alloc_extent_state_atomic(prealloc);
1002 BUG_ON(!prealloc);
1003
1004 /*
1005 * Avoid to free 'prealloc' if it can be merged with
1006 * the later extent.
1007 */
1008 err = insert_state(tree, prealloc, start, this_end,
1009 NULL, NULL, &bits, changeset);
1010 if (err)
1011 extent_io_tree_panic(tree, err);
1012
1013 cache_state(prealloc, cached_state);
1014 prealloc = NULL;
1015 start = this_end + 1;
1016 goto search_again;
1017 }
1018 /*
1019 * | ---- desired range ---- |
1020 * | state |
1021 * We need to split the extent, and set the bit
1022 * on the first half
1023 */
1024 if (state->start <= end && state->end > end) {
1025 if (state->state & exclusive_bits) {
1026 *failed_start = start;
1027 err = -EEXIST;
1028 goto out;
1029 }
1030
1031 prealloc = alloc_extent_state_atomic(prealloc);
1032 BUG_ON(!prealloc);
1033 err = split_state(tree, state, prealloc, end + 1);
1034 if (err)
1035 extent_io_tree_panic(tree, err);
1036
1037 set_state_bits(tree, prealloc, &bits, changeset);
1038 cache_state(prealloc, cached_state);
1039 merge_state(tree, prealloc);
1040 prealloc = NULL;
1041 goto out;
1042 }
1043
1044search_again:
1045 if (start > end)
1046 goto out;
1047 spin_unlock(&tree->lock);
1048 if (gfpflags_allow_blocking(mask))
1049 cond_resched();
1050 goto again;
1051
1052out:
1053 spin_unlock(&tree->lock);
1054 if (prealloc)
1055 free_extent_state(prealloc);
1056
1057 return err;
1058
1059}
1060
1061int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1062 unsigned bits, u64 * failed_start,
1063 struct extent_state **cached_state, gfp_t mask)
1064{
1065 return __set_extent_bit(tree, start, end, bits, 0, failed_start,
1066 cached_state, mask, NULL);
1067}
1068
1069
1070/**
1071 * convert_extent_bit - convert all bits in a given range from one bit to
1072 * another
1073 * @tree: the io tree to search
1074 * @start: the start offset in bytes
1075 * @end: the end offset in bytes (inclusive)
1076 * @bits: the bits to set in this range
1077 * @clear_bits: the bits to clear in this range
1078 * @cached_state: state that we're going to cache
1079 *
1080 * This will go through and set bits for the given range. If any states exist
1081 * already in this range they are set with the given bit and cleared of the
1082 * clear_bits. This is only meant to be used by things that are mergeable, ie
1083 * converting from say DELALLOC to DIRTY. This is not meant to be used with
1084 * boundary bits like LOCK.
1085 *
1086 * All allocations are done with GFP_NOFS.
1087 */
1088int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1089 unsigned bits, unsigned clear_bits,
1090 struct extent_state **cached_state)
1091{
1092 struct extent_state *state;
1093 struct extent_state *prealloc = NULL;
1094 struct rb_node *node;
1095 struct rb_node **p;
1096 struct rb_node *parent;
1097 int err = 0;
1098 u64 last_start;
1099 u64 last_end;
1100 bool first_iteration = true;
1101
1102 btrfs_debug_check_extent_io_range(tree, start, end);
1103
1104again:
1105 if (!prealloc) {
1106 /*
1107 * Best effort, don't worry if extent state allocation fails
1108 * here for the first iteration. We might have a cached state
1109 * that matches exactly the target range, in which case no
1110 * extent state allocations are needed. We'll only know this
1111 * after locking the tree.
1112 */
1113 prealloc = alloc_extent_state(GFP_NOFS);
1114 if (!prealloc && !first_iteration)
1115 return -ENOMEM;
1116 }
1117
1118 spin_lock(&tree->lock);
1119 if (cached_state && *cached_state) {
1120 state = *cached_state;
1121 if (state->start <= start && state->end > start &&
1122 extent_state_in_tree(state)) {
1123 node = &state->rb_node;
1124 goto hit_next;
1125 }
1126 }
1127
1128 /*
1129 * this search will find all the extents that end after
1130 * our range starts.
1131 */
1132 node = tree_search_for_insert(tree, start, &p, &parent);
1133 if (!node) {
1134 prealloc = alloc_extent_state_atomic(prealloc);
1135 if (!prealloc) {
1136 err = -ENOMEM;
1137 goto out;
1138 }
1139 err = insert_state(tree, prealloc, start, end,
1140 &p, &parent, &bits, NULL);
1141 if (err)
1142 extent_io_tree_panic(tree, err);
1143 cache_state(prealloc, cached_state);
1144 prealloc = NULL;
1145 goto out;
1146 }
1147 state = rb_entry(node, struct extent_state, rb_node);
1148hit_next:
1149 last_start = state->start;
1150 last_end = state->end;
1151
1152 /*
1153 * | ---- desired range ---- |
1154 * | state |
1155 *
1156 * Just lock what we found and keep going
1157 */
1158 if (state->start == start && state->end <= end) {
1159 set_state_bits(tree, state, &bits, NULL);
1160 cache_state(state, cached_state);
1161 state = clear_state_bit(tree, state, &clear_bits, 0, NULL);
1162 if (last_end == (u64)-1)
1163 goto out;
1164 start = last_end + 1;
1165 if (start < end && state && state->start == start &&
1166 !need_resched())
1167 goto hit_next;
1168 goto search_again;
1169 }
1170
1171 /*
1172 * | ---- desired range ---- |
1173 * | state |
1174 * or
1175 * | ------------- state -------------- |
1176 *
1177 * We need to split the extent we found, and may flip bits on
1178 * second half.
1179 *
1180 * If the extent we found extends past our
1181 * range, we just split and search again. It'll get split
1182 * again the next time though.
1183 *
1184 * If the extent we found is inside our range, we set the
1185 * desired bit on it.
1186 */
1187 if (state->start < start) {
1188 prealloc = alloc_extent_state_atomic(prealloc);
1189 if (!prealloc) {
1190 err = -ENOMEM;
1191 goto out;
1192 }
1193 err = split_state(tree, state, prealloc, start);
1194 if (err)
1195 extent_io_tree_panic(tree, err);
1196 prealloc = NULL;
1197 if (err)
1198 goto out;
1199 if (state->end <= end) {
1200 set_state_bits(tree, state, &bits, NULL);
1201 cache_state(state, cached_state);
1202 state = clear_state_bit(tree, state, &clear_bits, 0,
1203 NULL);
1204 if (last_end == (u64)-1)
1205 goto out;
1206 start = last_end + 1;
1207 if (start < end && state && state->start == start &&
1208 !need_resched())
1209 goto hit_next;
1210 }
1211 goto search_again;
1212 }
1213 /*
1214 * | ---- desired range ---- |
1215 * | state | or | state |
1216 *
1217 * There's a hole, we need to insert something in it and
1218 * ignore the extent we found.
1219 */
1220 if (state->start > start) {
1221 u64 this_end;
1222 if (end < last_start)
1223 this_end = end;
1224 else
1225 this_end = last_start - 1;
1226
1227 prealloc = alloc_extent_state_atomic(prealloc);
1228 if (!prealloc) {
1229 err = -ENOMEM;
1230 goto out;
1231 }
1232
1233 /*
1234 * Avoid to free 'prealloc' if it can be merged with
1235 * the later extent.
1236 */
1237 err = insert_state(tree, prealloc, start, this_end,
1238 NULL, NULL, &bits, NULL);
1239 if (err)
1240 extent_io_tree_panic(tree, err);
1241 cache_state(prealloc, cached_state);
1242 prealloc = NULL;
1243 start = this_end + 1;
1244 goto search_again;
1245 }
1246 /*
1247 * | ---- desired range ---- |
1248 * | state |
1249 * We need to split the extent, and set the bit
1250 * on the first half
1251 */
1252 if (state->start <= end && state->end > end) {
1253 prealloc = alloc_extent_state_atomic(prealloc);
1254 if (!prealloc) {
1255 err = -ENOMEM;
1256 goto out;
1257 }
1258
1259 err = split_state(tree, state, prealloc, end + 1);
1260 if (err)
1261 extent_io_tree_panic(tree, err);
1262
1263 set_state_bits(tree, prealloc, &bits, NULL);
1264 cache_state(prealloc, cached_state);
1265 clear_state_bit(tree, prealloc, &clear_bits, 0, NULL);
1266 prealloc = NULL;
1267 goto out;
1268 }
1269
1270search_again:
1271 if (start > end)
1272 goto out;
1273 spin_unlock(&tree->lock);
1274 cond_resched();
1275 first_iteration = false;
1276 goto again;
1277
1278out:
1279 spin_unlock(&tree->lock);
1280 if (prealloc)
1281 free_extent_state(prealloc);
1282
1283 return err;
1284}
1285
1286/* wrappers around set/clear extent bit */
1287int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1288 unsigned bits, struct extent_changeset *changeset)
1289{
1290 /*
1291 * We don't support EXTENT_LOCKED yet, as current changeset will
1292 * record any bits changed, so for EXTENT_LOCKED case, it will
1293 * either fail with -EEXIST or changeset will record the whole
1294 * range.
1295 */
1296 BUG_ON(bits & EXTENT_LOCKED);
1297
1298 return __set_extent_bit(tree, start, end, bits, 0, NULL, NULL, GFP_NOFS,
1299 changeset);
1300}
1301
1302int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1303 unsigned bits, int wake, int delete,
1304 struct extent_state **cached, gfp_t mask)
1305{
1306 return __clear_extent_bit(tree, start, end, bits, wake, delete,
1307 cached, mask, NULL);
1308}
1309
1310int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1311 unsigned bits, struct extent_changeset *changeset)
1312{
1313 /*
1314 * Don't support EXTENT_LOCKED case, same reason as
1315 * set_record_extent_bits().
1316 */
1317 BUG_ON(bits & EXTENT_LOCKED);
1318
1319 return __clear_extent_bit(tree, start, end, bits, 0, 0, NULL, GFP_NOFS,
1320 changeset);
1321}
1322
1323/*
1324 * either insert or lock state struct between start and end use mask to tell
1325 * us if waiting is desired.
1326 */
1327int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1328 struct extent_state **cached_state)
1329{
1330 int err;
1331 u64 failed_start;
1332
1333 while (1) {
1334 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED,
1335 EXTENT_LOCKED, &failed_start,
1336 cached_state, GFP_NOFS, NULL);
1337 if (err == -EEXIST) {
1338 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
1339 start = failed_start;
1340 } else
1341 break;
1342 WARN_ON(start > end);
1343 }
1344 return err;
1345}
1346
1347int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1348{
1349 int err;
1350 u64 failed_start;
1351
1352 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1353 &failed_start, NULL, GFP_NOFS, NULL);
1354 if (err == -EEXIST) {
1355 if (failed_start > start)
1356 clear_extent_bit(tree, start, failed_start - 1,
1357 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
1358 return 0;
1359 }
1360 return 1;
1361}
1362
1363void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
1364{
1365 unsigned long index = start >> PAGE_SHIFT;
1366 unsigned long end_index = end >> PAGE_SHIFT;
1367 struct page *page;
1368
1369 while (index <= end_index) {
1370 page = find_get_page(inode->i_mapping, index);
1371 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1372 clear_page_dirty_for_io(page);
1373 put_page(page);
1374 index++;
1375 }
1376}
1377
1378void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
1379{
1380 unsigned long index = start >> PAGE_SHIFT;
1381 unsigned long end_index = end >> PAGE_SHIFT;
1382 struct page *page;
1383
1384 while (index <= end_index) {
1385 page = find_get_page(inode->i_mapping, index);
1386 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1387 __set_page_dirty_nobuffers(page);
1388 account_page_redirty(page);
1389 put_page(page);
1390 index++;
1391 }
1392}
1393
1394/*
1395 * helper function to set both pages and extents in the tree writeback
1396 */
1397static void set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1398{
1399 unsigned long index = start >> PAGE_SHIFT;
1400 unsigned long end_index = end >> PAGE_SHIFT;
1401 struct page *page;
1402
1403 while (index <= end_index) {
1404 page = find_get_page(tree->mapping, index);
1405 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1406 set_page_writeback(page);
1407 put_page(page);
1408 index++;
1409 }
1410}
1411
1412/* find the first state struct with 'bits' set after 'start', and
1413 * return it. tree->lock must be held. NULL will returned if
1414 * nothing was found after 'start'
1415 */
1416static struct extent_state *
1417find_first_extent_bit_state(struct extent_io_tree *tree,
1418 u64 start, unsigned bits)
1419{
1420 struct rb_node *node;
1421 struct extent_state *state;
1422
1423 /*
1424 * this search will find all the extents that end after
1425 * our range starts.
1426 */
1427 node = tree_search(tree, start);
1428 if (!node)
1429 goto out;
1430
1431 while (1) {
1432 state = rb_entry(node, struct extent_state, rb_node);
1433 if (state->end >= start && (state->state & bits))
1434 return state;
1435
1436 node = rb_next(node);
1437 if (!node)
1438 break;
1439 }
1440out:
1441 return NULL;
1442}
1443
1444/*
1445 * find the first offset in the io tree with 'bits' set. zero is
1446 * returned if we find something, and *start_ret and *end_ret are
1447 * set to reflect the state struct that was found.
1448 *
1449 * If nothing was found, 1 is returned. If found something, return 0.
1450 */
1451int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1452 u64 *start_ret, u64 *end_ret, unsigned bits,
1453 struct extent_state **cached_state)
1454{
1455 struct extent_state *state;
1456 struct rb_node *n;
1457 int ret = 1;
1458
1459 spin_lock(&tree->lock);
1460 if (cached_state && *cached_state) {
1461 state = *cached_state;
1462 if (state->end == start - 1 && extent_state_in_tree(state)) {
1463 n = rb_next(&state->rb_node);
1464 while (n) {
1465 state = rb_entry(n, struct extent_state,
1466 rb_node);
1467 if (state->state & bits)
1468 goto got_it;
1469 n = rb_next(n);
1470 }
1471 free_extent_state(*cached_state);
1472 *cached_state = NULL;
1473 goto out;
1474 }
1475 free_extent_state(*cached_state);
1476 *cached_state = NULL;
1477 }
1478
1479 state = find_first_extent_bit_state(tree, start, bits);
1480got_it:
1481 if (state) {
1482 cache_state_if_flags(state, cached_state, 0);
1483 *start_ret = state->start;
1484 *end_ret = state->end;
1485 ret = 0;
1486 }
1487out:
1488 spin_unlock(&tree->lock);
1489 return ret;
1490}
1491
1492/*
1493 * find a contiguous range of bytes in the file marked as delalloc, not
1494 * more than 'max_bytes'. start and end are used to return the range,
1495 *
1496 * 1 is returned if we find something, 0 if nothing was in the tree
1497 */
1498static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1499 u64 *start, u64 *end, u64 max_bytes,
1500 struct extent_state **cached_state)
1501{
1502 struct rb_node *node;
1503 struct extent_state *state;
1504 u64 cur_start = *start;
1505 u64 found = 0;
1506 u64 total_bytes = 0;
1507
1508 spin_lock(&tree->lock);
1509
1510 /*
1511 * this search will find all the extents that end after
1512 * our range starts.
1513 */
1514 node = tree_search(tree, cur_start);
1515 if (!node) {
1516 if (!found)
1517 *end = (u64)-1;
1518 goto out;
1519 }
1520
1521 while (1) {
1522 state = rb_entry(node, struct extent_state, rb_node);
1523 if (found && (state->start != cur_start ||
1524 (state->state & EXTENT_BOUNDARY))) {
1525 goto out;
1526 }
1527 if (!(state->state & EXTENT_DELALLOC)) {
1528 if (!found)
1529 *end = state->end;
1530 goto out;
1531 }
1532 if (!found) {
1533 *start = state->start;
1534 *cached_state = state;
1535 atomic_inc(&state->refs);
1536 }
1537 found++;
1538 *end = state->end;
1539 cur_start = state->end + 1;
1540 node = rb_next(node);
1541 total_bytes += state->end - state->start + 1;
1542 if (total_bytes >= max_bytes)
1543 break;
1544 if (!node)
1545 break;
1546 }
1547out:
1548 spin_unlock(&tree->lock);
1549 return found;
1550}
1551
1552static noinline void __unlock_for_delalloc(struct inode *inode,
1553 struct page *locked_page,
1554 u64 start, u64 end)
1555{
1556 int ret;
1557 struct page *pages[16];
1558 unsigned long index = start >> PAGE_SHIFT;
1559 unsigned long end_index = end >> PAGE_SHIFT;
1560 unsigned long nr_pages = end_index - index + 1;
1561 int i;
1562
1563 if (index == locked_page->index && end_index == index)
1564 return;
1565
1566 while (nr_pages > 0) {
1567 ret = find_get_pages_contig(inode->i_mapping, index,
1568 min_t(unsigned long, nr_pages,
1569 ARRAY_SIZE(pages)), pages);
1570 for (i = 0; i < ret; i++) {
1571 if (pages[i] != locked_page)
1572 unlock_page(pages[i]);
1573 put_page(pages[i]);
1574 }
1575 nr_pages -= ret;
1576 index += ret;
1577 cond_resched();
1578 }
1579}
1580
1581static noinline int lock_delalloc_pages(struct inode *inode,
1582 struct page *locked_page,
1583 u64 delalloc_start,
1584 u64 delalloc_end)
1585{
1586 unsigned long index = delalloc_start >> PAGE_SHIFT;
1587 unsigned long start_index = index;
1588 unsigned long end_index = delalloc_end >> PAGE_SHIFT;
1589 unsigned long pages_locked = 0;
1590 struct page *pages[16];
1591 unsigned long nrpages;
1592 int ret;
1593 int i;
1594
1595 /* the caller is responsible for locking the start index */
1596 if (index == locked_page->index && index == end_index)
1597 return 0;
1598
1599 /* skip the page at the start index */
1600 nrpages = end_index - index + 1;
1601 while (nrpages > 0) {
1602 ret = find_get_pages_contig(inode->i_mapping, index,
1603 min_t(unsigned long,
1604 nrpages, ARRAY_SIZE(pages)), pages);
1605 if (ret == 0) {
1606 ret = -EAGAIN;
1607 goto done;
1608 }
1609 /* now we have an array of pages, lock them all */
1610 for (i = 0; i < ret; i++) {
1611 /*
1612 * the caller is taking responsibility for
1613 * locked_page
1614 */
1615 if (pages[i] != locked_page) {
1616 lock_page(pages[i]);
1617 if (!PageDirty(pages[i]) ||
1618 pages[i]->mapping != inode->i_mapping) {
1619 ret = -EAGAIN;
1620 unlock_page(pages[i]);
1621 put_page(pages[i]);
1622 goto done;
1623 }
1624 }
1625 put_page(pages[i]);
1626 pages_locked++;
1627 }
1628 nrpages -= ret;
1629 index += ret;
1630 cond_resched();
1631 }
1632 ret = 0;
1633done:
1634 if (ret && pages_locked) {
1635 __unlock_for_delalloc(inode, locked_page,
1636 delalloc_start,
1637 ((u64)(start_index + pages_locked - 1)) <<
1638 PAGE_SHIFT);
1639 }
1640 return ret;
1641}
1642
1643/*
1644 * find a contiguous range of bytes in the file marked as delalloc, not
1645 * more than 'max_bytes'. start and end are used to return the range,
1646 *
1647 * 1 is returned if we find something, 0 if nothing was in the tree
1648 */
1649STATIC u64 find_lock_delalloc_range(struct inode *inode,
1650 struct extent_io_tree *tree,
1651 struct page *locked_page, u64 *start,
1652 u64 *end, u64 max_bytes)
1653{
1654 u64 delalloc_start;
1655 u64 delalloc_end;
1656 u64 found;
1657 struct extent_state *cached_state = NULL;
1658 int ret;
1659 int loops = 0;
1660
1661again:
1662 /* step one, find a bunch of delalloc bytes starting at start */
1663 delalloc_start = *start;
1664 delalloc_end = 0;
1665 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1666 max_bytes, &cached_state);
1667 if (!found || delalloc_end <= *start) {
1668 *start = delalloc_start;
1669 *end = delalloc_end;
1670 free_extent_state(cached_state);
1671 return 0;
1672 }
1673
1674 /*
1675 * start comes from the offset of locked_page. We have to lock
1676 * pages in order, so we can't process delalloc bytes before
1677 * locked_page
1678 */
1679 if (delalloc_start < *start)
1680 delalloc_start = *start;
1681
1682 /*
1683 * make sure to limit the number of pages we try to lock down
1684 */
1685 if (delalloc_end + 1 - delalloc_start > max_bytes)
1686 delalloc_end = delalloc_start + max_bytes - 1;
1687
1688 /* step two, lock all the pages after the page that has start */
1689 ret = lock_delalloc_pages(inode, locked_page,
1690 delalloc_start, delalloc_end);
1691 if (ret == -EAGAIN) {
1692 /* some of the pages are gone, lets avoid looping by
1693 * shortening the size of the delalloc range we're searching
1694 */
1695 free_extent_state(cached_state);
1696 cached_state = NULL;
1697 if (!loops) {
1698 max_bytes = PAGE_SIZE;
1699 loops = 1;
1700 goto again;
1701 } else {
1702 found = 0;
1703 goto out_failed;
1704 }
1705 }
1706 BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
1707
1708 /* step three, lock the state bits for the whole range */
1709 lock_extent_bits(tree, delalloc_start, delalloc_end, &cached_state);
1710
1711 /* then test to make sure it is all still delalloc */
1712 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1713 EXTENT_DELALLOC, 1, cached_state);
1714 if (!ret) {
1715 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1716 &cached_state, GFP_NOFS);
1717 __unlock_for_delalloc(inode, locked_page,
1718 delalloc_start, delalloc_end);
1719 cond_resched();
1720 goto again;
1721 }
1722 free_extent_state(cached_state);
1723 *start = delalloc_start;
1724 *end = delalloc_end;
1725out_failed:
1726 return found;
1727}
1728
1729void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
1730 u64 delalloc_end, struct page *locked_page,
1731 unsigned clear_bits,
1732 unsigned long page_ops)
1733{
1734 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
1735 int ret;
1736 struct page *pages[16];
1737 unsigned long index = start >> PAGE_SHIFT;
1738 unsigned long end_index = end >> PAGE_SHIFT;
1739 unsigned long nr_pages = end_index - index + 1;
1740 int i;
1741
1742 clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1743 if (page_ops == 0)
1744 return;
1745
1746 if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
1747 mapping_set_error(inode->i_mapping, -EIO);
1748
1749 while (nr_pages > 0) {
1750 ret = find_get_pages_contig(inode->i_mapping, index,
1751 min_t(unsigned long,
1752 nr_pages, ARRAY_SIZE(pages)), pages);
1753 for (i = 0; i < ret; i++) {
1754
1755 if (page_ops & PAGE_SET_PRIVATE2)
1756 SetPagePrivate2(pages[i]);
1757
1758 if (pages[i] == locked_page) {
1759 put_page(pages[i]);
1760 continue;
1761 }
1762 if (page_ops & PAGE_CLEAR_DIRTY)
1763 clear_page_dirty_for_io(pages[i]);
1764 if (page_ops & PAGE_SET_WRITEBACK)
1765 set_page_writeback(pages[i]);
1766 if (page_ops & PAGE_SET_ERROR)
1767 SetPageError(pages[i]);
1768 if (page_ops & PAGE_END_WRITEBACK)
1769 end_page_writeback(pages[i]);
1770 if (page_ops & PAGE_UNLOCK)
1771 unlock_page(pages[i]);
1772 put_page(pages[i]);
1773 }
1774 nr_pages -= ret;
1775 index += ret;
1776 cond_resched();
1777 }
1778}
1779
1780/*
1781 * count the number of bytes in the tree that have a given bit(s)
1782 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1783 * cached. The total number found is returned.
1784 */
1785u64 count_range_bits(struct extent_io_tree *tree,
1786 u64 *start, u64 search_end, u64 max_bytes,
1787 unsigned bits, int contig)
1788{
1789 struct rb_node *node;
1790 struct extent_state *state;
1791 u64 cur_start = *start;
1792 u64 total_bytes = 0;
1793 u64 last = 0;
1794 int found = 0;
1795
1796 if (WARN_ON(search_end <= cur_start))
1797 return 0;
1798
1799 spin_lock(&tree->lock);
1800 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1801 total_bytes = tree->dirty_bytes;
1802 goto out;
1803 }
1804 /*
1805 * this search will find all the extents that end after
1806 * our range starts.
1807 */
1808 node = tree_search(tree, cur_start);
1809 if (!node)
1810 goto out;
1811
1812 while (1) {
1813 state = rb_entry(node, struct extent_state, rb_node);
1814 if (state->start > search_end)
1815 break;
1816 if (contig && found && state->start > last + 1)
1817 break;
1818 if (state->end >= cur_start && (state->state & bits) == bits) {
1819 total_bytes += min(search_end, state->end) + 1 -
1820 max(cur_start, state->start);
1821 if (total_bytes >= max_bytes)
1822 break;
1823 if (!found) {
1824 *start = max(cur_start, state->start);
1825 found = 1;
1826 }
1827 last = state->end;
1828 } else if (contig && found) {
1829 break;
1830 }
1831 node = rb_next(node);
1832 if (!node)
1833 break;
1834 }
1835out:
1836 spin_unlock(&tree->lock);
1837 return total_bytes;
1838}
1839
1840/*
1841 * set the private field for a given byte offset in the tree. If there isn't
1842 * an extent_state there already, this does nothing.
1843 */
1844static noinline int set_state_failrec(struct extent_io_tree *tree, u64 start,
1845 struct io_failure_record *failrec)
1846{
1847 struct rb_node *node;
1848 struct extent_state *state;
1849 int ret = 0;
1850
1851 spin_lock(&tree->lock);
1852 /*
1853 * this search will find all the extents that end after
1854 * our range starts.
1855 */
1856 node = tree_search(tree, start);
1857 if (!node) {
1858 ret = -ENOENT;
1859 goto out;
1860 }
1861 state = rb_entry(node, struct extent_state, rb_node);
1862 if (state->start != start) {
1863 ret = -ENOENT;
1864 goto out;
1865 }
1866 state->failrec = failrec;
1867out:
1868 spin_unlock(&tree->lock);
1869 return ret;
1870}
1871
1872static noinline int get_state_failrec(struct extent_io_tree *tree, u64 start,
1873 struct io_failure_record **failrec)
1874{
1875 struct rb_node *node;
1876 struct extent_state *state;
1877 int ret = 0;
1878
1879 spin_lock(&tree->lock);
1880 /*
1881 * this search will find all the extents that end after
1882 * our range starts.
1883 */
1884 node = tree_search(tree, start);
1885 if (!node) {
1886 ret = -ENOENT;
1887 goto out;
1888 }
1889 state = rb_entry(node, struct extent_state, rb_node);
1890 if (state->start != start) {
1891 ret = -ENOENT;
1892 goto out;
1893 }
1894 *failrec = state->failrec;
1895out:
1896 spin_unlock(&tree->lock);
1897 return ret;
1898}
1899
1900/*
1901 * searches a range in the state tree for a given mask.
1902 * If 'filled' == 1, this returns 1 only if every extent in the tree
1903 * has the bits set. Otherwise, 1 is returned if any bit in the
1904 * range is found set.
1905 */
1906int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1907 unsigned bits, int filled, struct extent_state *cached)
1908{
1909 struct extent_state *state = NULL;
1910 struct rb_node *node;
1911 int bitset = 0;
1912
1913 spin_lock(&tree->lock);
1914 if (cached && extent_state_in_tree(cached) && cached->start <= start &&
1915 cached->end > start)
1916 node = &cached->rb_node;
1917 else
1918 node = tree_search(tree, start);
1919 while (node && start <= end) {
1920 state = rb_entry(node, struct extent_state, rb_node);
1921
1922 if (filled && state->start > start) {
1923 bitset = 0;
1924 break;
1925 }
1926
1927 if (state->start > end)
1928 break;
1929
1930 if (state->state & bits) {
1931 bitset = 1;
1932 if (!filled)
1933 break;
1934 } else if (filled) {
1935 bitset = 0;
1936 break;
1937 }
1938
1939 if (state->end == (u64)-1)
1940 break;
1941
1942 start = state->end + 1;
1943 if (start > end)
1944 break;
1945 node = rb_next(node);
1946 if (!node) {
1947 if (filled)
1948 bitset = 0;
1949 break;
1950 }
1951 }
1952 spin_unlock(&tree->lock);
1953 return bitset;
1954}
1955
1956/*
1957 * helper function to set a given page up to date if all the
1958 * extents in the tree for that page are up to date
1959 */
1960static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1961{
1962 u64 start = page_offset(page);
1963 u64 end = start + PAGE_SIZE - 1;
1964 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1965 SetPageUptodate(page);
1966}
1967
1968int free_io_failure(struct inode *inode, struct io_failure_record *rec)
1969{
1970 int ret;
1971 int err = 0;
1972 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1973
1974 set_state_failrec(failure_tree, rec->start, NULL);
1975 ret = clear_extent_bits(failure_tree, rec->start,
1976 rec->start + rec->len - 1,
1977 EXTENT_LOCKED | EXTENT_DIRTY);
1978 if (ret)
1979 err = ret;
1980
1981 ret = clear_extent_bits(&BTRFS_I(inode)->io_tree, rec->start,
1982 rec->start + rec->len - 1,
1983 EXTENT_DAMAGED);
1984 if (ret && !err)
1985 err = ret;
1986
1987 kfree(rec);
1988 return err;
1989}
1990
1991/*
1992 * this bypasses the standard btrfs submit functions deliberately, as
1993 * the standard behavior is to write all copies in a raid setup. here we only
1994 * want to write the one bad copy. so we do the mapping for ourselves and issue
1995 * submit_bio directly.
1996 * to avoid any synchronization issues, wait for the data after writing, which
1997 * actually prevents the read that triggered the error from finishing.
1998 * currently, there can be no more than two copies of every data bit. thus,
1999 * exactly one rewrite is required.
2000 */
2001int repair_io_failure(struct inode *inode, u64 start, u64 length, u64 logical,
2002 struct page *page, unsigned int pg_offset, int mirror_num)
2003{
2004 struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2005 struct bio *bio;
2006 struct btrfs_device *dev;
2007 u64 map_length = 0;
2008 u64 sector;
2009 struct btrfs_bio *bbio = NULL;
2010 struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
2011 int ret;
2012
2013 ASSERT(!(fs_info->sb->s_flags & MS_RDONLY));
2014 BUG_ON(!mirror_num);
2015
2016 /* we can't repair anything in raid56 yet */
2017 if (btrfs_is_parity_mirror(map_tree, logical, length, mirror_num))
2018 return 0;
2019
2020 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2021 if (!bio)
2022 return -EIO;
2023 bio->bi_iter.bi_size = 0;
2024 map_length = length;
2025
2026 /*
2027 * Avoid races with device replace and make sure our bbio has devices
2028 * associated to its stripes that don't go away while we are doing the
2029 * read repair operation.
2030 */
2031 btrfs_bio_counter_inc_blocked(fs_info);
2032 ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
2033 &map_length, &bbio, mirror_num);
2034 if (ret) {
2035 btrfs_bio_counter_dec(fs_info);
2036 bio_put(bio);
2037 return -EIO;
2038 }
2039 BUG_ON(mirror_num != bbio->mirror_num);
2040 sector = bbio->stripes[mirror_num-1].physical >> 9;
2041 bio->bi_iter.bi_sector = sector;
2042 dev = bbio->stripes[mirror_num-1].dev;
2043 btrfs_put_bbio(bbio);
2044 if (!dev || !dev->bdev || !dev->writeable) {
2045 btrfs_bio_counter_dec(fs_info);
2046 bio_put(bio);
2047 return -EIO;
2048 }
2049 bio->bi_bdev = dev->bdev;
2050 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
2051 bio_add_page(bio, page, length, pg_offset);
2052
2053 if (btrfsic_submit_bio_wait(bio)) {
2054 /* try to remap that extent elsewhere? */
2055 btrfs_bio_counter_dec(fs_info);
2056 bio_put(bio);
2057 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2058 return -EIO;
2059 }
2060
2061 btrfs_info_rl_in_rcu(fs_info,
2062 "read error corrected: ino %llu off %llu (dev %s sector %llu)",
2063 btrfs_ino(inode), start,
2064 rcu_str_deref(dev->name), sector);
2065 btrfs_bio_counter_dec(fs_info);
2066 bio_put(bio);
2067 return 0;
2068}
2069
2070int repair_eb_io_failure(struct btrfs_fs_info *fs_info,
2071 struct extent_buffer *eb, int mirror_num)
2072{
2073 u64 start = eb->start;
2074 unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
2075 int ret = 0;
2076
2077 if (fs_info->sb->s_flags & MS_RDONLY)
2078 return -EROFS;
2079
2080 for (i = 0; i < num_pages; i++) {
2081 struct page *p = eb->pages[i];
2082
2083 ret = repair_io_failure(fs_info->btree_inode, start,
2084 PAGE_SIZE, start, p,
2085 start - page_offset(p), mirror_num);
2086 if (ret)
2087 break;
2088 start += PAGE_SIZE;
2089 }
2090
2091 return ret;
2092}
2093
2094/*
2095 * each time an IO finishes, we do a fast check in the IO failure tree
2096 * to see if we need to process or clean up an io_failure_record
2097 */
2098int clean_io_failure(struct inode *inode, u64 start, struct page *page,
2099 unsigned int pg_offset)
2100{
2101 u64 private;
2102 struct io_failure_record *failrec;
2103 struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2104 struct extent_state *state;
2105 int num_copies;
2106 int ret;
2107
2108 private = 0;
2109 ret = count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
2110 (u64)-1, 1, EXTENT_DIRTY, 0);
2111 if (!ret)
2112 return 0;
2113
2114 ret = get_state_failrec(&BTRFS_I(inode)->io_failure_tree, start,
2115 &failrec);
2116 if (ret)
2117 return 0;
2118
2119 BUG_ON(!failrec->this_mirror);
2120
2121 if (failrec->in_validation) {
2122 /* there was no real error, just free the record */
2123 btrfs_debug(fs_info,
2124 "clean_io_failure: freeing dummy error at %llu",
2125 failrec->start);
2126 goto out;
2127 }
2128 if (fs_info->sb->s_flags & MS_RDONLY)
2129 goto out;
2130
2131 spin_lock(&BTRFS_I(inode)->io_tree.lock);
2132 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
2133 failrec->start,
2134 EXTENT_LOCKED);
2135 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
2136
2137 if (state && state->start <= failrec->start &&
2138 state->end >= failrec->start + failrec->len - 1) {
2139 num_copies = btrfs_num_copies(fs_info, failrec->logical,
2140 failrec->len);
2141 if (num_copies > 1) {
2142 repair_io_failure(inode, start, failrec->len,
2143 failrec->logical, page,
2144 pg_offset, failrec->failed_mirror);
2145 }
2146 }
2147
2148out:
2149 free_io_failure(inode, failrec);
2150
2151 return 0;
2152}
2153
2154/*
2155 * Can be called when
2156 * - hold extent lock
2157 * - under ordered extent
2158 * - the inode is freeing
2159 */
2160void btrfs_free_io_failure_record(struct inode *inode, u64 start, u64 end)
2161{
2162 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2163 struct io_failure_record *failrec;
2164 struct extent_state *state, *next;
2165
2166 if (RB_EMPTY_ROOT(&failure_tree->state))
2167 return;
2168
2169 spin_lock(&failure_tree->lock);
2170 state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
2171 while (state) {
2172 if (state->start > end)
2173 break;
2174
2175 ASSERT(state->end <= end);
2176
2177 next = next_state(state);
2178
2179 failrec = state->failrec;
2180 free_extent_state(state);
2181 kfree(failrec);
2182
2183 state = next;
2184 }
2185 spin_unlock(&failure_tree->lock);
2186}
2187
2188int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
2189 struct io_failure_record **failrec_ret)
2190{
2191 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2192 struct io_failure_record *failrec;
2193 struct extent_map *em;
2194 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2195 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2196 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2197 int ret;
2198 u64 logical;
2199
2200 ret = get_state_failrec(failure_tree, start, &failrec);
2201 if (ret) {
2202 failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
2203 if (!failrec)
2204 return -ENOMEM;
2205
2206 failrec->start = start;
2207 failrec->len = end - start + 1;
2208 failrec->this_mirror = 0;
2209 failrec->bio_flags = 0;
2210 failrec->in_validation = 0;
2211
2212 read_lock(&em_tree->lock);
2213 em = lookup_extent_mapping(em_tree, start, failrec->len);
2214 if (!em) {
2215 read_unlock(&em_tree->lock);
2216 kfree(failrec);
2217 return -EIO;
2218 }
2219
2220 if (em->start > start || em->start + em->len <= start) {
2221 free_extent_map(em);
2222 em = NULL;
2223 }
2224 read_unlock(&em_tree->lock);
2225 if (!em) {
2226 kfree(failrec);
2227 return -EIO;
2228 }
2229
2230 logical = start - em->start;
2231 logical = em->block_start + logical;
2232 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2233 logical = em->block_start;
2234 failrec->bio_flags = EXTENT_BIO_COMPRESSED;
2235 extent_set_compress_type(&failrec->bio_flags,
2236 em->compress_type);
2237 }
2238
2239 btrfs_debug(fs_info,
2240 "Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu",
2241 logical, start, failrec->len);
2242
2243 failrec->logical = logical;
2244 free_extent_map(em);
2245
2246 /* set the bits in the private failure tree */
2247 ret = set_extent_bits(failure_tree, start, end,
2248 EXTENT_LOCKED | EXTENT_DIRTY);
2249 if (ret >= 0)
2250 ret = set_state_failrec(failure_tree, start, failrec);
2251 /* set the bits in the inode's tree */
2252 if (ret >= 0)
2253 ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED);
2254 if (ret < 0) {
2255 kfree(failrec);
2256 return ret;
2257 }
2258 } else {
2259 btrfs_debug(fs_info,
2260 "Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d",
2261 failrec->logical, failrec->start, failrec->len,
2262 failrec->in_validation);
2263 /*
2264 * when data can be on disk more than twice, add to failrec here
2265 * (e.g. with a list for failed_mirror) to make
2266 * clean_io_failure() clean all those errors at once.
2267 */
2268 }
2269
2270 *failrec_ret = failrec;
2271
2272 return 0;
2273}
2274
2275int btrfs_check_repairable(struct inode *inode, struct bio *failed_bio,
2276 struct io_failure_record *failrec, int failed_mirror)
2277{
2278 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2279 int num_copies;
2280
2281 num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
2282 if (num_copies == 1) {
2283 /*
2284 * we only have a single copy of the data, so don't bother with
2285 * all the retry and error correction code that follows. no
2286 * matter what the error is, it is very likely to persist.
2287 */
2288 btrfs_debug(fs_info,
2289 "Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
2290 num_copies, failrec->this_mirror, failed_mirror);
2291 return 0;
2292 }
2293
2294 /*
2295 * there are two premises:
2296 * a) deliver good data to the caller
2297 * b) correct the bad sectors on disk
2298 */
2299 if (failed_bio->bi_vcnt > 1) {
2300 /*
2301 * to fulfill b), we need to know the exact failing sectors, as
2302 * we don't want to rewrite any more than the failed ones. thus,
2303 * we need separate read requests for the failed bio
2304 *
2305 * if the following BUG_ON triggers, our validation request got
2306 * merged. we need separate requests for our algorithm to work.
2307 */
2308 BUG_ON(failrec->in_validation);
2309 failrec->in_validation = 1;
2310 failrec->this_mirror = failed_mirror;
2311 } else {
2312 /*
2313 * we're ready to fulfill a) and b) alongside. get a good copy
2314 * of the failed sector and if we succeed, we have setup
2315 * everything for repair_io_failure to do the rest for us.
2316 */
2317 if (failrec->in_validation) {
2318 BUG_ON(failrec->this_mirror != failed_mirror);
2319 failrec->in_validation = 0;
2320 failrec->this_mirror = 0;
2321 }
2322 failrec->failed_mirror = failed_mirror;
2323 failrec->this_mirror++;
2324 if (failrec->this_mirror == failed_mirror)
2325 failrec->this_mirror++;
2326 }
2327
2328 if (failrec->this_mirror > num_copies) {
2329 btrfs_debug(fs_info,
2330 "Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
2331 num_copies, failrec->this_mirror, failed_mirror);
2332 return 0;
2333 }
2334
2335 return 1;
2336}
2337
2338
2339struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
2340 struct io_failure_record *failrec,
2341 struct page *page, int pg_offset, int icsum,
2342 bio_end_io_t *endio_func, void *data)
2343{
2344 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2345 struct bio *bio;
2346 struct btrfs_io_bio *btrfs_failed_bio;
2347 struct btrfs_io_bio *btrfs_bio;
2348
2349 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2350 if (!bio)
2351 return NULL;
2352
2353 bio->bi_end_io = endio_func;
2354 bio->bi_iter.bi_sector = failrec->logical >> 9;
2355 bio->bi_bdev = fs_info->fs_devices->latest_bdev;
2356 bio->bi_iter.bi_size = 0;
2357 bio->bi_private = data;
2358
2359 btrfs_failed_bio = btrfs_io_bio(failed_bio);
2360 if (btrfs_failed_bio->csum) {
2361 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
2362
2363 btrfs_bio = btrfs_io_bio(bio);
2364 btrfs_bio->csum = btrfs_bio->csum_inline;
2365 icsum *= csum_size;
2366 memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
2367 csum_size);
2368 }
2369
2370 bio_add_page(bio, page, failrec->len, pg_offset);
2371
2372 return bio;
2373}
2374
2375/*
2376 * this is a generic handler for readpage errors (default
2377 * readpage_io_failed_hook). if other copies exist, read those and write back
2378 * good data to the failed position. does not investigate in remapping the
2379 * failed extent elsewhere, hoping the device will be smart enough to do this as
2380 * needed
2381 */
2382
2383static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
2384 struct page *page, u64 start, u64 end,
2385 int failed_mirror)
2386{
2387 struct io_failure_record *failrec;
2388 struct inode *inode = page->mapping->host;
2389 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2390 struct bio *bio;
2391 int read_mode = 0;
2392 int ret;
2393
2394 BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
2395
2396 ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
2397 if (ret)
2398 return ret;
2399
2400 ret = btrfs_check_repairable(inode, failed_bio, failrec, failed_mirror);
2401 if (!ret) {
2402 free_io_failure(inode, failrec);
2403 return -EIO;
2404 }
2405
2406 if (failed_bio->bi_vcnt > 1)
2407 read_mode |= REQ_FAILFAST_DEV;
2408
2409 phy_offset >>= inode->i_sb->s_blocksize_bits;
2410 bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
2411 start - page_offset(page),
2412 (int)phy_offset, failed_bio->bi_end_io,
2413 NULL);
2414 if (!bio) {
2415 free_io_failure(inode, failrec);
2416 return -EIO;
2417 }
2418 bio_set_op_attrs(bio, REQ_OP_READ, read_mode);
2419
2420 btrfs_debug(btrfs_sb(inode->i_sb),
2421 "Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d",
2422 read_mode, failrec->this_mirror, failrec->in_validation);
2423
2424 ret = tree->ops->submit_bio_hook(inode, bio, failrec->this_mirror,
2425 failrec->bio_flags, 0);
2426 if (ret) {
2427 free_io_failure(inode, failrec);
2428 bio_put(bio);
2429 }
2430
2431 return ret;
2432}
2433
2434/* lots and lots of room for performance fixes in the end_bio funcs */
2435
2436void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
2437{
2438 int uptodate = (err == 0);
2439 struct extent_io_tree *tree;
2440 int ret = 0;
2441
2442 tree = &BTRFS_I(page->mapping->host)->io_tree;
2443
2444 if (tree->ops && tree->ops->writepage_end_io_hook) {
2445 ret = tree->ops->writepage_end_io_hook(page, start,
2446 end, NULL, uptodate);
2447 if (ret)
2448 uptodate = 0;
2449 }
2450
2451 if (!uptodate) {
2452 ClearPageUptodate(page);
2453 SetPageError(page);
2454 ret = ret < 0 ? ret : -EIO;
2455 mapping_set_error(page->mapping, ret);
2456 }
2457}
2458
2459/*
2460 * after a writepage IO is done, we need to:
2461 * clear the uptodate bits on error
2462 * clear the writeback bits in the extent tree for this IO
2463 * end_page_writeback if the page has no more pending IO
2464 *
2465 * Scheduling is not allowed, so the extent state tree is expected
2466 * to have one and only one object corresponding to this IO.
2467 */
2468static void end_bio_extent_writepage(struct bio *bio)
2469{
2470 struct bio_vec *bvec;
2471 u64 start;
2472 u64 end;
2473 int i;
2474
2475 bio_for_each_segment_all(bvec, bio, i) {
2476 struct page *page = bvec->bv_page;
2477 struct inode *inode = page->mapping->host;
2478 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2479
2480 /* We always issue full-page reads, but if some block
2481 * in a page fails to read, blk_update_request() will
2482 * advance bv_offset and adjust bv_len to compensate.
2483 * Print a warning for nonzero offsets, and an error
2484 * if they don't add up to a full page. */
2485 if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2486 if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2487 btrfs_err(fs_info,
2488 "partial page write in btrfs with offset %u and length %u",
2489 bvec->bv_offset, bvec->bv_len);
2490 else
2491 btrfs_info(fs_info,
2492 "incomplete page write in btrfs with offset %u and length %u",
2493 bvec->bv_offset, bvec->bv_len);
2494 }
2495
2496 start = page_offset(page);
2497 end = start + bvec->bv_offset + bvec->bv_len - 1;
2498
2499 end_extent_writepage(page, bio->bi_error, start, end);
2500 end_page_writeback(page);
2501 }
2502
2503 bio_put(bio);
2504}
2505
2506static void
2507endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
2508 int uptodate)
2509{
2510 struct extent_state *cached = NULL;
2511 u64 end = start + len - 1;
2512
2513 if (uptodate && tree->track_uptodate)
2514 set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
2515 unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
2516}
2517
2518/*
2519 * after a readpage IO is done, we need to:
2520 * clear the uptodate bits on error
2521 * set the uptodate bits if things worked
2522 * set the page up to date if all extents in the tree are uptodate
2523 * clear the lock bit in the extent tree
2524 * unlock the page if there are no other extents locked for it
2525 *
2526 * Scheduling is not allowed, so the extent state tree is expected
2527 * to have one and only one object corresponding to this IO.
2528 */
2529static void end_bio_extent_readpage(struct bio *bio)
2530{
2531 struct bio_vec *bvec;
2532 int uptodate = !bio->bi_error;
2533 struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2534 struct extent_io_tree *tree;
2535 u64 offset = 0;
2536 u64 start;
2537 u64 end;
2538 u64 len;
2539 u64 extent_start = 0;
2540 u64 extent_len = 0;
2541 int mirror;
2542 int ret;
2543 int i;
2544
2545 bio_for_each_segment_all(bvec, bio, i) {
2546 struct page *page = bvec->bv_page;
2547 struct inode *inode = page->mapping->host;
2548 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2549
2550 btrfs_debug(fs_info,
2551 "end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
2552 (u64)bio->bi_iter.bi_sector, bio->bi_error,
2553 io_bio->mirror_num);
2554 tree = &BTRFS_I(inode)->io_tree;
2555
2556 /* We always issue full-page reads, but if some block
2557 * in a page fails to read, blk_update_request() will
2558 * advance bv_offset and adjust bv_len to compensate.
2559 * Print a warning for nonzero offsets, and an error
2560 * if they don't add up to a full page. */
2561 if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2562 if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2563 btrfs_err(fs_info,
2564 "partial page read in btrfs with offset %u and length %u",
2565 bvec->bv_offset, bvec->bv_len);
2566 else
2567 btrfs_info(fs_info,
2568 "incomplete page read in btrfs with offset %u and length %u",
2569 bvec->bv_offset, bvec->bv_len);
2570 }
2571
2572 start = page_offset(page);
2573 end = start + bvec->bv_offset + bvec->bv_len - 1;
2574 len = bvec->bv_len;
2575
2576 mirror = io_bio->mirror_num;
2577 if (likely(uptodate && tree->ops &&
2578 tree->ops->readpage_end_io_hook)) {
2579 ret = tree->ops->readpage_end_io_hook(io_bio, offset,
2580 page, start, end,
2581 mirror);
2582 if (ret)
2583 uptodate = 0;
2584 else
2585 clean_io_failure(inode, start, page, 0);
2586 }
2587
2588 if (likely(uptodate))
2589 goto readpage_ok;
2590
2591 if (tree->ops && tree->ops->readpage_io_failed_hook) {
2592 ret = tree->ops->readpage_io_failed_hook(page, mirror);
2593 if (!ret && !bio->bi_error)
2594 uptodate = 1;
2595 } else {
2596 /*
2597 * The generic bio_readpage_error handles errors the
2598 * following way: If possible, new read requests are
2599 * created and submitted and will end up in
2600 * end_bio_extent_readpage as well (if we're lucky, not
2601 * in the !uptodate case). In that case it returns 0 and
2602 * we just go on with the next page in our bio. If it
2603 * can't handle the error it will return -EIO and we
2604 * remain responsible for that page.
2605 */
2606 ret = bio_readpage_error(bio, offset, page, start, end,
2607 mirror);
2608 if (ret == 0) {
2609 uptodate = !bio->bi_error;
2610 offset += len;
2611 continue;
2612 }
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, bio->bi_error);
2660 bio_put(bio);
2661}
2662
2663/*
2664 * this allocates from the btrfs_bioset. We're returning a bio right now
2665 * but you can call btrfs_io_bio for the appropriate container_of magic
2666 */
2667struct bio *
2668btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
2669 gfp_t gfp_flags)
2670{
2671 struct btrfs_io_bio *btrfs_bio;
2672 struct bio *bio;
2673
2674 bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
2675
2676 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2677 while (!bio && (nr_vecs /= 2)) {
2678 bio = bio_alloc_bioset(gfp_flags,
2679 nr_vecs, btrfs_bioset);
2680 }
2681 }
2682
2683 if (bio) {
2684 bio->bi_bdev = bdev;
2685 bio->bi_iter.bi_sector = first_sector;
2686 btrfs_bio = btrfs_io_bio(bio);
2687 btrfs_bio->csum = NULL;
2688 btrfs_bio->csum_allocated = NULL;
2689 btrfs_bio->end_io = NULL;
2690 }
2691 return bio;
2692}
2693
2694struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
2695{
2696 struct btrfs_io_bio *btrfs_bio;
2697 struct bio *new;
2698
2699 new = bio_clone_bioset(bio, gfp_mask, btrfs_bioset);
2700 if (new) {
2701 btrfs_bio = btrfs_io_bio(new);
2702 btrfs_bio->csum = NULL;
2703 btrfs_bio->csum_allocated = NULL;
2704 btrfs_bio->end_io = NULL;
2705 }
2706 return new;
2707}
2708
2709/* this also allocates from the btrfs_bioset */
2710struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
2711{
2712 struct btrfs_io_bio *btrfs_bio;
2713 struct bio *bio;
2714
2715 bio = bio_alloc_bioset(gfp_mask, nr_iovecs, btrfs_bioset);
2716 if (bio) {
2717 btrfs_bio = btrfs_io_bio(bio);
2718 btrfs_bio->csum = NULL;
2719 btrfs_bio->csum_allocated = NULL;
2720 btrfs_bio->end_io = NULL;
2721 }
2722 return bio;
2723}
2724
2725
2726static int __must_check submit_one_bio(struct bio *bio, int mirror_num,
2727 unsigned long bio_flags)
2728{
2729 int ret = 0;
2730 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
2731 struct page *page = bvec->bv_page;
2732 struct extent_io_tree *tree = bio->bi_private;
2733 u64 start;
2734
2735 start = page_offset(page) + bvec->bv_offset;
2736
2737 bio->bi_private = NULL;
2738 bio_get(bio);
2739
2740 if (tree->ops && tree->ops->submit_bio_hook)
2741 ret = tree->ops->submit_bio_hook(page->mapping->host, bio,
2742 mirror_num, bio_flags, start);
2743 else
2744 btrfsic_submit_bio(bio);
2745
2746 bio_put(bio);
2747 return ret;
2748}
2749
2750static int merge_bio(struct extent_io_tree *tree, struct page *page,
2751 unsigned long offset, size_t size, struct bio *bio,
2752 unsigned long bio_flags)
2753{
2754 int ret = 0;
2755 if (tree->ops && tree->ops->merge_bio_hook)
2756 ret = tree->ops->merge_bio_hook(page, offset, size, bio,
2757 bio_flags);
2758 return ret;
2759
2760}
2761
2762static int submit_extent_page(int op, int op_flags, struct extent_io_tree *tree,
2763 struct writeback_control *wbc,
2764 struct page *page, sector_t sector,
2765 size_t size, unsigned long offset,
2766 struct block_device *bdev,
2767 struct bio **bio_ret,
2768 unsigned long max_pages,
2769 bio_end_io_t end_io_func,
2770 int mirror_num,
2771 unsigned long prev_bio_flags,
2772 unsigned long bio_flags,
2773 bool force_bio_submit)
2774{
2775 int ret = 0;
2776 struct bio *bio;
2777 int contig = 0;
2778 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2779 size_t page_size = min_t(size_t, size, PAGE_SIZE);
2780
2781 if (bio_ret && *bio_ret) {
2782 bio = *bio_ret;
2783 if (old_compressed)
2784 contig = bio->bi_iter.bi_sector == sector;
2785 else
2786 contig = bio_end_sector(bio) == sector;
2787
2788 if (prev_bio_flags != bio_flags || !contig ||
2789 force_bio_submit ||
2790 merge_bio(tree, page, offset, page_size, bio, bio_flags) ||
2791 bio_add_page(bio, page, page_size, offset) < page_size) {
2792 ret = submit_one_bio(bio, mirror_num, prev_bio_flags);
2793 if (ret < 0) {
2794 *bio_ret = NULL;
2795 return ret;
2796 }
2797 bio = NULL;
2798 } else {
2799 if (wbc)
2800 wbc_account_io(wbc, page, page_size);
2801 return 0;
2802 }
2803 }
2804
2805 bio = btrfs_bio_alloc(bdev, sector, BIO_MAX_PAGES,
2806 GFP_NOFS | __GFP_HIGH);
2807 if (!bio)
2808 return -ENOMEM;
2809
2810 bio_add_page(bio, page, page_size, offset);
2811 bio->bi_end_io = end_io_func;
2812 bio->bi_private = tree;
2813 bio_set_op_attrs(bio, op, op_flags);
2814 if (wbc) {
2815 wbc_init_bio(wbc, bio);
2816 wbc_account_io(wbc, page, page_size);
2817 }
2818
2819 if (bio_ret)
2820 *bio_ret = bio;
2821 else
2822 ret = submit_one_bio(bio, mirror_num, bio_flags);
2823
2824 return ret;
2825}
2826
2827static void attach_extent_buffer_page(struct extent_buffer *eb,
2828 struct page *page)
2829{
2830 if (!PagePrivate(page)) {
2831 SetPagePrivate(page);
2832 get_page(page);
2833 set_page_private(page, (unsigned long)eb);
2834 } else {
2835 WARN_ON(page->private != (unsigned long)eb);
2836 }
2837}
2838
2839void set_page_extent_mapped(struct page *page)
2840{
2841 if (!PagePrivate(page)) {
2842 SetPagePrivate(page);
2843 get_page(page);
2844 set_page_private(page, EXTENT_PAGE_PRIVATE);
2845 }
2846}
2847
2848static struct extent_map *
2849__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
2850 u64 start, u64 len, get_extent_t *get_extent,
2851 struct extent_map **em_cached)
2852{
2853 struct extent_map *em;
2854
2855 if (em_cached && *em_cached) {
2856 em = *em_cached;
2857 if (extent_map_in_tree(em) && start >= em->start &&
2858 start < extent_map_end(em)) {
2859 atomic_inc(&em->refs);
2860 return em;
2861 }
2862
2863 free_extent_map(em);
2864 *em_cached = NULL;
2865 }
2866
2867 em = get_extent(inode, page, pg_offset, start, len, 0);
2868 if (em_cached && !IS_ERR_OR_NULL(em)) {
2869 BUG_ON(*em_cached);
2870 atomic_inc(&em->refs);
2871 *em_cached = em;
2872 }
2873 return em;
2874}
2875/*
2876 * basic readpage implementation. Locked extent state structs are inserted
2877 * into the tree that are removed when the IO is done (by the end_io
2878 * handlers)
2879 * XXX JDM: This needs looking at to ensure proper page locking
2880 * return 0 on success, otherwise return error
2881 */
2882static int __do_readpage(struct extent_io_tree *tree,
2883 struct page *page,
2884 get_extent_t *get_extent,
2885 struct extent_map **em_cached,
2886 struct bio **bio, int mirror_num,
2887 unsigned long *bio_flags, int read_flags,
2888 u64 *prev_em_start)
2889{
2890 struct inode *inode = page->mapping->host;
2891 u64 start = page_offset(page);
2892 u64 page_end = start + PAGE_SIZE - 1;
2893 u64 end;
2894 u64 cur = start;
2895 u64 extent_offset;
2896 u64 last_byte = i_size_read(inode);
2897 u64 block_start;
2898 u64 cur_end;
2899 sector_t sector;
2900 struct extent_map *em;
2901 struct block_device *bdev;
2902 int ret = 0;
2903 int nr = 0;
2904 size_t pg_offset = 0;
2905 size_t iosize;
2906 size_t disk_io_size;
2907 size_t blocksize = inode->i_sb->s_blocksize;
2908 unsigned long this_bio_flag = 0;
2909
2910 set_page_extent_mapped(page);
2911
2912 end = page_end;
2913 if (!PageUptodate(page)) {
2914 if (cleancache_get_page(page) == 0) {
2915 BUG_ON(blocksize != PAGE_SIZE);
2916 unlock_extent(tree, start, end);
2917 goto out;
2918 }
2919 }
2920
2921 if (page->index == last_byte >> PAGE_SHIFT) {
2922 char *userpage;
2923 size_t zero_offset = last_byte & (PAGE_SIZE - 1);
2924
2925 if (zero_offset) {
2926 iosize = PAGE_SIZE - zero_offset;
2927 userpage = kmap_atomic(page);
2928 memset(userpage + zero_offset, 0, iosize);
2929 flush_dcache_page(page);
2930 kunmap_atomic(userpage);
2931 }
2932 }
2933 while (cur <= end) {
2934 unsigned long pnr = (last_byte >> PAGE_SHIFT) + 1;
2935 bool force_bio_submit = false;
2936
2937 if (cur >= last_byte) {
2938 char *userpage;
2939 struct extent_state *cached = NULL;
2940
2941 iosize = PAGE_SIZE - pg_offset;
2942 userpage = kmap_atomic(page);
2943 memset(userpage + pg_offset, 0, iosize);
2944 flush_dcache_page(page);
2945 kunmap_atomic(userpage);
2946 set_extent_uptodate(tree, cur, cur + iosize - 1,
2947 &cached, GFP_NOFS);
2948 unlock_extent_cached(tree, cur,
2949 cur + iosize - 1,
2950 &cached, GFP_NOFS);
2951 break;
2952 }
2953 em = __get_extent_map(inode, page, pg_offset, cur,
2954 end - cur + 1, get_extent, em_cached);
2955 if (IS_ERR_OR_NULL(em)) {
2956 SetPageError(page);
2957 unlock_extent(tree, cur, end);
2958 break;
2959 }
2960 extent_offset = cur - em->start;
2961 BUG_ON(extent_map_end(em) <= cur);
2962 BUG_ON(end < cur);
2963
2964 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2965 this_bio_flag |= EXTENT_BIO_COMPRESSED;
2966 extent_set_compress_type(&this_bio_flag,
2967 em->compress_type);
2968 }
2969
2970 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2971 cur_end = min(extent_map_end(em) - 1, end);
2972 iosize = ALIGN(iosize, blocksize);
2973 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
2974 disk_io_size = em->block_len;
2975 sector = em->block_start >> 9;
2976 } else {
2977 sector = (em->block_start + extent_offset) >> 9;
2978 disk_io_size = iosize;
2979 }
2980 bdev = em->bdev;
2981 block_start = em->block_start;
2982 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2983 block_start = EXTENT_MAP_HOLE;
2984
2985 /*
2986 * If we have a file range that points to a compressed extent
2987 * and it's followed by a consecutive file range that points to
2988 * to the same compressed extent (possibly with a different
2989 * offset and/or length, so it either points to the whole extent
2990 * or only part of it), we must make sure we do not submit a
2991 * single bio to populate the pages for the 2 ranges because
2992 * this makes the compressed extent read zero out the pages
2993 * belonging to the 2nd range. Imagine the following scenario:
2994 *
2995 * File layout
2996 * [0 - 8K] [8K - 24K]
2997 * | |
2998 * | |
2999 * points to extent X, points to extent X,
3000 * offset 4K, length of 8K offset 0, length 16K
3001 *
3002 * [extent X, compressed length = 4K uncompressed length = 16K]
3003 *
3004 * If the bio to read the compressed extent covers both ranges,
3005 * it will decompress extent X into the pages belonging to the
3006 * first range and then it will stop, zeroing out the remaining
3007 * pages that belong to the other range that points to extent X.
3008 * So here we make sure we submit 2 bios, one for the first
3009 * range and another one for the third range. Both will target
3010 * the same physical extent from disk, but we can't currently
3011 * make the compressed bio endio callback populate the pages
3012 * for both ranges because each compressed bio is tightly
3013 * coupled with a single extent map, and each range can have
3014 * an extent map with a different offset value relative to the
3015 * uncompressed data of our extent and different lengths. This
3016 * is a corner case so we prioritize correctness over
3017 * non-optimal behavior (submitting 2 bios for the same extent).
3018 */
3019 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
3020 prev_em_start && *prev_em_start != (u64)-1 &&
3021 *prev_em_start != em->orig_start)
3022 force_bio_submit = true;
3023
3024 if (prev_em_start)
3025 *prev_em_start = em->orig_start;
3026
3027 free_extent_map(em);
3028 em = NULL;
3029
3030 /* we've found a hole, just zero and go on */
3031 if (block_start == EXTENT_MAP_HOLE) {
3032 char *userpage;
3033 struct extent_state *cached = NULL;
3034
3035 userpage = kmap_atomic(page);
3036 memset(userpage + pg_offset, 0, iosize);
3037 flush_dcache_page(page);
3038 kunmap_atomic(userpage);
3039
3040 set_extent_uptodate(tree, cur, cur + iosize - 1,
3041 &cached, GFP_NOFS);
3042 unlock_extent_cached(tree, cur,
3043 cur + iosize - 1,
3044 &cached, GFP_NOFS);
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 pnr -= page->index;
3070 ret = submit_extent_page(REQ_OP_READ, read_flags, tree, NULL,
3071 page, sector, disk_io_size, pg_offset,
3072 bdev, bio, pnr,
3073 end_bio_extent_readpage, mirror_num,
3074 *bio_flags,
3075 this_bio_flag,
3076 force_bio_submit);
3077 if (!ret) {
3078 nr++;
3079 *bio_flags = this_bio_flag;
3080 } else {
3081 SetPageError(page);
3082 unlock_extent(tree, cur, cur + iosize - 1);
3083 goto out;
3084 }
3085 cur = cur + iosize;
3086 pg_offset += iosize;
3087 }
3088out:
3089 if (!nr) {
3090 if (!PageError(page))
3091 SetPageUptodate(page);
3092 unlock_page(page);
3093 }
3094 return ret;
3095}
3096
3097static inline void __do_contiguous_readpages(struct extent_io_tree *tree,
3098 struct page *pages[], int nr_pages,
3099 u64 start, u64 end,
3100 get_extent_t *get_extent,
3101 struct extent_map **em_cached,
3102 struct bio **bio, int mirror_num,
3103 unsigned long *bio_flags,
3104 u64 *prev_em_start)
3105{
3106 struct inode *inode;
3107 struct btrfs_ordered_extent *ordered;
3108 int index;
3109
3110 inode = pages[0]->mapping->host;
3111 while (1) {
3112 lock_extent(tree, start, end);
3113 ordered = btrfs_lookup_ordered_range(inode, start,
3114 end - start + 1);
3115 if (!ordered)
3116 break;
3117 unlock_extent(tree, start, end);
3118 btrfs_start_ordered_extent(inode, ordered, 1);
3119 btrfs_put_ordered_extent(ordered);
3120 }
3121
3122 for (index = 0; index < nr_pages; index++) {
3123 __do_readpage(tree, pages[index], get_extent, em_cached, bio,
3124 mirror_num, bio_flags, 0, prev_em_start);
3125 put_page(pages[index]);
3126 }
3127}
3128
3129static void __extent_readpages(struct extent_io_tree *tree,
3130 struct page *pages[],
3131 int nr_pages, get_extent_t *get_extent,
3132 struct extent_map **em_cached,
3133 struct bio **bio, int mirror_num,
3134 unsigned long *bio_flags,
3135 u64 *prev_em_start)
3136{
3137 u64 start = 0;
3138 u64 end = 0;
3139 u64 page_start;
3140 int index;
3141 int first_index = 0;
3142
3143 for (index = 0; index < nr_pages; index++) {
3144 page_start = page_offset(pages[index]);
3145 if (!end) {
3146 start = page_start;
3147 end = start + PAGE_SIZE - 1;
3148 first_index = index;
3149 } else if (end + 1 == page_start) {
3150 end += PAGE_SIZE;
3151 } else {
3152 __do_contiguous_readpages(tree, &pages[first_index],
3153 index - first_index, start,
3154 end, get_extent, em_cached,
3155 bio, mirror_num, bio_flags,
3156 prev_em_start);
3157 start = page_start;
3158 end = start + PAGE_SIZE - 1;
3159 first_index = index;
3160 }
3161 }
3162
3163 if (end)
3164 __do_contiguous_readpages(tree, &pages[first_index],
3165 index - first_index, start,
3166 end, get_extent, em_cached, bio,
3167 mirror_num, bio_flags,
3168 prev_em_start);
3169}
3170
3171static int __extent_read_full_page(struct extent_io_tree *tree,
3172 struct page *page,
3173 get_extent_t *get_extent,
3174 struct bio **bio, int mirror_num,
3175 unsigned long *bio_flags, int read_flags)
3176{
3177 struct inode *inode = page->mapping->host;
3178 struct btrfs_ordered_extent *ordered;
3179 u64 start = page_offset(page);
3180 u64 end = start + PAGE_SIZE - 1;
3181 int ret;
3182
3183 while (1) {
3184 lock_extent(tree, start, end);
3185 ordered = btrfs_lookup_ordered_range(inode, start,
3186 PAGE_SIZE);
3187 if (!ordered)
3188 break;
3189 unlock_extent(tree, start, end);
3190 btrfs_start_ordered_extent(inode, ordered, 1);
3191 btrfs_put_ordered_extent(ordered);
3192 }
3193
3194 ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
3195 bio_flags, read_flags, NULL);
3196 return ret;
3197}
3198
3199int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3200 get_extent_t *get_extent, int mirror_num)
3201{
3202 struct bio *bio = NULL;
3203 unsigned long bio_flags = 0;
3204 int ret;
3205
3206 ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3207 &bio_flags, 0);
3208 if (bio)
3209 ret = submit_one_bio(bio, mirror_num, bio_flags);
3210 return ret;
3211}
3212
3213static void update_nr_written(struct page *page, struct writeback_control *wbc,
3214 unsigned long nr_written)
3215{
3216 wbc->nr_to_write -= nr_written;
3217}
3218
3219/*
3220 * helper for __extent_writepage, doing all of the delayed allocation setup.
3221 *
3222 * This returns 1 if our fill_delalloc function did all the work required
3223 * to write the page (copy into inline extent). In this case the IO has
3224 * been started and the page is already unlocked.
3225 *
3226 * This returns 0 if all went well (page still locked)
3227 * This returns < 0 if there were errors (page still locked)
3228 */
3229static noinline_for_stack int writepage_delalloc(struct inode *inode,
3230 struct page *page, struct writeback_control *wbc,
3231 struct extent_page_data *epd,
3232 u64 delalloc_start,
3233 unsigned long *nr_written)
3234{
3235 struct extent_io_tree *tree = epd->tree;
3236 u64 page_end = delalloc_start + PAGE_SIZE - 1;
3237 u64 nr_delalloc;
3238 u64 delalloc_to_write = 0;
3239 u64 delalloc_end = 0;
3240 int ret;
3241 int page_started = 0;
3242
3243 if (epd->extent_locked || !tree->ops || !tree->ops->fill_delalloc)
3244 return 0;
3245
3246 while (delalloc_end < page_end) {
3247 nr_delalloc = find_lock_delalloc_range(inode, tree,
3248 page,
3249 &delalloc_start,
3250 &delalloc_end,
3251 BTRFS_MAX_EXTENT_SIZE);
3252 if (nr_delalloc == 0) {
3253 delalloc_start = delalloc_end + 1;
3254 continue;
3255 }
3256 ret = tree->ops->fill_delalloc(inode, page,
3257 delalloc_start,
3258 delalloc_end,
3259 &page_started,
3260 nr_written);
3261 /* File system has been set read-only */
3262 if (ret) {
3263 SetPageError(page);
3264 /* fill_delalloc should be return < 0 for error
3265 * but just in case, we use > 0 here meaning the
3266 * IO is started, so we don't want to return > 0
3267 * unless things are going well.
3268 */
3269 ret = ret < 0 ? ret : -EIO;
3270 goto done;
3271 }
3272 /*
3273 * delalloc_end is already one less than the total length, so
3274 * we don't subtract one from PAGE_SIZE
3275 */
3276 delalloc_to_write += (delalloc_end - delalloc_start +
3277 PAGE_SIZE) >> PAGE_SHIFT;
3278 delalloc_start = delalloc_end + 1;
3279 }
3280 if (wbc->nr_to_write < delalloc_to_write) {
3281 int thresh = 8192;
3282
3283 if (delalloc_to_write < thresh * 2)
3284 thresh = delalloc_to_write;
3285 wbc->nr_to_write = min_t(u64, delalloc_to_write,
3286 thresh);
3287 }
3288
3289 /* did the fill delalloc function already unlock and start
3290 * the IO?
3291 */
3292 if (page_started) {
3293 /*
3294 * we've unlocked the page, so we can't update
3295 * the mapping's writeback index, just update
3296 * nr_to_write.
3297 */
3298 wbc->nr_to_write -= *nr_written;
3299 return 1;
3300 }
3301
3302 ret = 0;
3303
3304done:
3305 return ret;
3306}
3307
3308/*
3309 * helper for __extent_writepage. This calls the writepage start hooks,
3310 * and does the loop to map the page into extents and bios.
3311 *
3312 * We return 1 if the IO is started and the page is unlocked,
3313 * 0 if all went well (page still locked)
3314 * < 0 if there were errors (page still locked)
3315 */
3316static noinline_for_stack int __extent_writepage_io(struct inode *inode,
3317 struct page *page,
3318 struct writeback_control *wbc,
3319 struct extent_page_data *epd,
3320 loff_t i_size,
3321 unsigned long nr_written,
3322 int write_flags, int *nr_ret)
3323{
3324 struct extent_io_tree *tree = epd->tree;
3325 u64 start = page_offset(page);
3326 u64 page_end = start + PAGE_SIZE - 1;
3327 u64 end;
3328 u64 cur = start;
3329 u64 extent_offset;
3330 u64 block_start;
3331 u64 iosize;
3332 sector_t sector;
3333 struct extent_state *cached_state = NULL;
3334 struct extent_map *em;
3335 struct block_device *bdev;
3336 size_t pg_offset = 0;
3337 size_t blocksize;
3338 int ret = 0;
3339 int nr = 0;
3340 bool compressed;
3341
3342 if (tree->ops && tree->ops->writepage_start_hook) {
3343 ret = tree->ops->writepage_start_hook(page, start,
3344 page_end);
3345 if (ret) {
3346 /* Fixup worker will requeue */
3347 if (ret == -EBUSY)
3348 wbc->pages_skipped++;
3349 else
3350 redirty_page_for_writepage(wbc, page);
3351
3352 update_nr_written(page, wbc, nr_written);
3353 unlock_page(page);
3354 ret = 1;
3355 goto done_unlocked;
3356 }
3357 }
3358
3359 /*
3360 * we don't want to touch the inode after unlocking the page,
3361 * so we update the mapping writeback index now
3362 */
3363 update_nr_written(page, wbc, nr_written + 1);
3364
3365 end = page_end;
3366 if (i_size <= start) {
3367 if (tree->ops && tree->ops->writepage_end_io_hook)
3368 tree->ops->writepage_end_io_hook(page, start,
3369 page_end, NULL, 1);
3370 goto done;
3371 }
3372
3373 blocksize = inode->i_sb->s_blocksize;
3374
3375 while (cur <= end) {
3376 u64 em_end;
3377 unsigned long max_nr;
3378
3379 if (cur >= i_size) {
3380 if (tree->ops && tree->ops->writepage_end_io_hook)
3381 tree->ops->writepage_end_io_hook(page, cur,
3382 page_end, NULL, 1);
3383 break;
3384 }
3385 em = epd->get_extent(inode, page, pg_offset, cur,
3386 end - cur + 1, 1);
3387 if (IS_ERR_OR_NULL(em)) {
3388 SetPageError(page);
3389 ret = PTR_ERR_OR_ZERO(em);
3390 break;
3391 }
3392
3393 extent_offset = cur - em->start;
3394 em_end = extent_map_end(em);
3395 BUG_ON(em_end <= cur);
3396 BUG_ON(end < cur);
3397 iosize = min(em_end - cur, end - cur + 1);
3398 iosize = ALIGN(iosize, blocksize);
3399 sector = (em->block_start + extent_offset) >> 9;
3400 bdev = em->bdev;
3401 block_start = em->block_start;
3402 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3403 free_extent_map(em);
3404 em = NULL;
3405
3406 /*
3407 * compressed and inline extents are written through other
3408 * paths in the FS
3409 */
3410 if (compressed || block_start == EXTENT_MAP_HOLE ||
3411 block_start == EXTENT_MAP_INLINE) {
3412 /*
3413 * end_io notification does not happen here for
3414 * compressed extents
3415 */
3416 if (!compressed && tree->ops &&
3417 tree->ops->writepage_end_io_hook)
3418 tree->ops->writepage_end_io_hook(page, cur,
3419 cur + iosize - 1,
3420 NULL, 1);
3421 else if (compressed) {
3422 /* we don't want to end_page_writeback on
3423 * a compressed extent. this happens
3424 * elsewhere
3425 */
3426 nr++;
3427 }
3428
3429 cur += iosize;
3430 pg_offset += iosize;
3431 continue;
3432 }
3433
3434 max_nr = (i_size >> PAGE_SHIFT) + 1;
3435
3436 set_range_writeback(tree, cur, cur + iosize - 1);
3437 if (!PageWriteback(page)) {
3438 btrfs_err(BTRFS_I(inode)->root->fs_info,
3439 "page %lu not writeback, cur %llu end %llu",
3440 page->index, cur, end);
3441 }
3442
3443 ret = submit_extent_page(REQ_OP_WRITE, write_flags, tree, wbc,
3444 page, sector, iosize, pg_offset,
3445 bdev, &epd->bio, max_nr,
3446 end_bio_extent_writepage,
3447 0, 0, 0, false);
3448 if (ret)
3449 SetPageError(page);
3450
3451 cur = cur + iosize;
3452 pg_offset += iosize;
3453 nr++;
3454 }
3455done:
3456 *nr_ret = nr;
3457
3458done_unlocked:
3459
3460 /* drop our reference on any cached states */
3461 free_extent_state(cached_state);
3462 return ret;
3463}
3464
3465/*
3466 * the writepage semantics are similar to regular writepage. extent
3467 * records are inserted to lock ranges in the tree, and as dirty areas
3468 * are found, they are marked writeback. Then the lock bits are removed
3469 * and the end_io handler clears the writeback ranges
3470 */
3471static int __extent_writepage(struct page *page, struct writeback_control *wbc,
3472 void *data)
3473{
3474 struct inode *inode = page->mapping->host;
3475 struct extent_page_data *epd = data;
3476 u64 start = page_offset(page);
3477 u64 page_end = start + PAGE_SIZE - 1;
3478 int ret;
3479 int nr = 0;
3480 size_t pg_offset = 0;
3481 loff_t i_size = i_size_read(inode);
3482 unsigned long end_index = i_size >> PAGE_SHIFT;
3483 int write_flags = 0;
3484 unsigned long nr_written = 0;
3485
3486 if (wbc->sync_mode == WB_SYNC_ALL)
3487 write_flags = REQ_SYNC;
3488
3489 trace___extent_writepage(page, inode, wbc);
3490
3491 WARN_ON(!PageLocked(page));
3492
3493 ClearPageError(page);
3494
3495 pg_offset = i_size & (PAGE_SIZE - 1);
3496 if (page->index > end_index ||
3497 (page->index == end_index && !pg_offset)) {
3498 page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
3499 unlock_page(page);
3500 return 0;
3501 }
3502
3503 if (page->index == end_index) {
3504 char *userpage;
3505
3506 userpage = kmap_atomic(page);
3507 memset(userpage + pg_offset, 0,
3508 PAGE_SIZE - pg_offset);
3509 kunmap_atomic(userpage);
3510 flush_dcache_page(page);
3511 }
3512
3513 pg_offset = 0;
3514
3515 set_page_extent_mapped(page);
3516
3517 ret = writepage_delalloc(inode, page, wbc, epd, start, &nr_written);
3518 if (ret == 1)
3519 goto done_unlocked;
3520 if (ret)
3521 goto done;
3522
3523 ret = __extent_writepage_io(inode, page, wbc, epd,
3524 i_size, nr_written, write_flags, &nr);
3525 if (ret == 1)
3526 goto done_unlocked;
3527
3528done:
3529 if (nr == 0) {
3530 /* make sure the mapping tag for page dirty gets cleared */
3531 set_page_writeback(page);
3532 end_page_writeback(page);
3533 }
3534 if (PageError(page)) {
3535 ret = ret < 0 ? ret : -EIO;
3536 end_extent_writepage(page, ret, start, page_end);
3537 }
3538 unlock_page(page);
3539 return ret;
3540
3541done_unlocked:
3542 return 0;
3543}
3544
3545void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3546{
3547 wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
3548 TASK_UNINTERRUPTIBLE);
3549}
3550
3551static noinline_for_stack int
3552lock_extent_buffer_for_io(struct extent_buffer *eb,
3553 struct btrfs_fs_info *fs_info,
3554 struct extent_page_data *epd)
3555{
3556 unsigned long i, num_pages;
3557 int flush = 0;
3558 int ret = 0;
3559
3560 if (!btrfs_try_tree_write_lock(eb)) {
3561 flush = 1;
3562 flush_write_bio(epd);
3563 btrfs_tree_lock(eb);
3564 }
3565
3566 if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
3567 btrfs_tree_unlock(eb);
3568 if (!epd->sync_io)
3569 return 0;
3570 if (!flush) {
3571 flush_write_bio(epd);
3572 flush = 1;
3573 }
3574 while (1) {
3575 wait_on_extent_buffer_writeback(eb);
3576 btrfs_tree_lock(eb);
3577 if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
3578 break;
3579 btrfs_tree_unlock(eb);
3580 }
3581 }
3582
3583 /*
3584 * We need to do this to prevent races in people who check if the eb is
3585 * under IO since we can end up having no IO bits set for a short period
3586 * of time.
3587 */
3588 spin_lock(&eb->refs_lock);
3589 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3590 set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3591 spin_unlock(&eb->refs_lock);
3592 btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3593 __percpu_counter_add(&fs_info->dirty_metadata_bytes,
3594 -eb->len,
3595 fs_info->dirty_metadata_batch);
3596 ret = 1;
3597 } else {
3598 spin_unlock(&eb->refs_lock);
3599 }
3600
3601 btrfs_tree_unlock(eb);
3602
3603 if (!ret)
3604 return ret;
3605
3606 num_pages = num_extent_pages(eb->start, eb->len);
3607 for (i = 0; i < num_pages; i++) {
3608 struct page *p = eb->pages[i];
3609
3610 if (!trylock_page(p)) {
3611 if (!flush) {
3612 flush_write_bio(epd);
3613 flush = 1;
3614 }
3615 lock_page(p);
3616 }
3617 }
3618
3619 return ret;
3620}
3621
3622static void end_extent_buffer_writeback(struct extent_buffer *eb)
3623{
3624 clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3625 smp_mb__after_atomic();
3626 wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
3627}
3628
3629static void set_btree_ioerr(struct page *page)
3630{
3631 struct extent_buffer *eb = (struct extent_buffer *)page->private;
3632
3633 SetPageError(page);
3634 if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
3635 return;
3636
3637 /*
3638 * If writeback for a btree extent that doesn't belong to a log tree
3639 * failed, increment the counter transaction->eb_write_errors.
3640 * We do this because while the transaction is running and before it's
3641 * committing (when we call filemap_fdata[write|wait]_range against
3642 * the btree inode), we might have
3643 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
3644 * returns an error or an error happens during writeback, when we're
3645 * committing the transaction we wouldn't know about it, since the pages
3646 * can be no longer dirty nor marked anymore for writeback (if a
3647 * subsequent modification to the extent buffer didn't happen before the
3648 * transaction commit), which makes filemap_fdata[write|wait]_range not
3649 * able to find the pages tagged with SetPageError at transaction
3650 * commit time. So if this happens we must abort the transaction,
3651 * otherwise we commit a super block with btree roots that point to
3652 * btree nodes/leafs whose content on disk is invalid - either garbage
3653 * or the content of some node/leaf from a past generation that got
3654 * cowed or deleted and is no longer valid.
3655 *
3656 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
3657 * not be enough - we need to distinguish between log tree extents vs
3658 * non-log tree extents, and the next filemap_fdatawait_range() call
3659 * will catch and clear such errors in the mapping - and that call might
3660 * be from a log sync and not from a transaction commit. Also, checking
3661 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
3662 * not done and would not be reliable - the eb might have been released
3663 * from memory and reading it back again means that flag would not be
3664 * set (since it's a runtime flag, not persisted on disk).
3665 *
3666 * Using the flags below in the btree inode also makes us achieve the
3667 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
3668 * writeback for all dirty pages and before filemap_fdatawait_range()
3669 * is called, the writeback for all dirty pages had already finished
3670 * with errors - because we were not using AS_EIO/AS_ENOSPC,
3671 * filemap_fdatawait_range() would return success, as it could not know
3672 * that writeback errors happened (the pages were no longer tagged for
3673 * writeback).
3674 */
3675 switch (eb->log_index) {
3676 case -1:
3677 set_bit(BTRFS_FS_BTREE_ERR, &eb->fs_info->flags);
3678 break;
3679 case 0:
3680 set_bit(BTRFS_FS_LOG1_ERR, &eb->fs_info->flags);
3681 break;
3682 case 1:
3683 set_bit(BTRFS_FS_LOG2_ERR, &eb->fs_info->flags);
3684 break;
3685 default:
3686 BUG(); /* unexpected, logic error */
3687 }
3688}
3689
3690static void end_bio_extent_buffer_writepage(struct bio *bio)
3691{
3692 struct bio_vec *bvec;
3693 struct extent_buffer *eb;
3694 int i, done;
3695
3696 bio_for_each_segment_all(bvec, bio, i) {
3697 struct page *page = bvec->bv_page;
3698
3699 eb = (struct extent_buffer *)page->private;
3700 BUG_ON(!eb);
3701 done = atomic_dec_and_test(&eb->io_pages);
3702
3703 if (bio->bi_error ||
3704 test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
3705 ClearPageUptodate(page);
3706 set_btree_ioerr(page);
3707 }
3708
3709 end_page_writeback(page);
3710
3711 if (!done)
3712 continue;
3713
3714 end_extent_buffer_writeback(eb);
3715 }
3716
3717 bio_put(bio);
3718}
3719
3720static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3721 struct btrfs_fs_info *fs_info,
3722 struct writeback_control *wbc,
3723 struct extent_page_data *epd)
3724{
3725 struct block_device *bdev = fs_info->fs_devices->latest_bdev;
3726 struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3727 u64 offset = eb->start;
3728 u32 nritems;
3729 unsigned long i, num_pages;
3730 unsigned long bio_flags = 0;
3731 unsigned long start, end;
3732 int write_flags = (epd->sync_io ? REQ_SYNC : 0) | REQ_META;
3733 int ret = 0;
3734
3735 clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
3736 num_pages = num_extent_pages(eb->start, eb->len);
3737 atomic_set(&eb->io_pages, num_pages);
3738 if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
3739 bio_flags = EXTENT_BIO_TREE_LOG;
3740
3741 /* set btree blocks beyond nritems with 0 to avoid stale content. */
3742 nritems = btrfs_header_nritems(eb);
3743 if (btrfs_header_level(eb) > 0) {
3744 end = btrfs_node_key_ptr_offset(nritems);
3745
3746 memzero_extent_buffer(eb, end, eb->len - end);
3747 } else {
3748 /*
3749 * leaf:
3750 * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
3751 */
3752 start = btrfs_item_nr_offset(nritems);
3753 end = btrfs_leaf_data(eb) + leaf_data_end(fs_info, eb);
3754 memzero_extent_buffer(eb, start, end - start);
3755 }
3756
3757 for (i = 0; i < num_pages; i++) {
3758 struct page *p = eb->pages[i];
3759
3760 clear_page_dirty_for_io(p);
3761 set_page_writeback(p);
3762 ret = submit_extent_page(REQ_OP_WRITE, write_flags, tree, wbc,
3763 p, offset >> 9, PAGE_SIZE, 0, bdev,
3764 &epd->bio, -1,
3765 end_bio_extent_buffer_writepage,
3766 0, epd->bio_flags, bio_flags, false);
3767 epd->bio_flags = bio_flags;
3768 if (ret) {
3769 set_btree_ioerr(p);
3770 end_page_writeback(p);
3771 if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
3772 end_extent_buffer_writeback(eb);
3773 ret = -EIO;
3774 break;
3775 }
3776 offset += PAGE_SIZE;
3777 update_nr_written(p, wbc, 1);
3778 unlock_page(p);
3779 }
3780
3781 if (unlikely(ret)) {
3782 for (; i < num_pages; i++) {
3783 struct page *p = eb->pages[i];
3784 clear_page_dirty_for_io(p);
3785 unlock_page(p);
3786 }
3787 }
3788
3789 return ret;
3790}
3791
3792int btree_write_cache_pages(struct address_space *mapping,
3793 struct writeback_control *wbc)
3794{
3795 struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
3796 struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
3797 struct extent_buffer *eb, *prev_eb = NULL;
3798 struct extent_page_data epd = {
3799 .bio = NULL,
3800 .tree = tree,
3801 .extent_locked = 0,
3802 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
3803 .bio_flags = 0,
3804 };
3805 int ret = 0;
3806 int done = 0;
3807 int nr_to_write_done = 0;
3808 struct pagevec pvec;
3809 int nr_pages;
3810 pgoff_t index;
3811 pgoff_t end; /* Inclusive */
3812 int scanned = 0;
3813 int tag;
3814
3815 pagevec_init(&pvec, 0);
3816 if (wbc->range_cyclic) {
3817 index = mapping->writeback_index; /* Start from prev offset */
3818 end = -1;
3819 } else {
3820 index = wbc->range_start >> PAGE_SHIFT;
3821 end = wbc->range_end >> PAGE_SHIFT;
3822 scanned = 1;
3823 }
3824 if (wbc->sync_mode == WB_SYNC_ALL)
3825 tag = PAGECACHE_TAG_TOWRITE;
3826 else
3827 tag = PAGECACHE_TAG_DIRTY;
3828retry:
3829 if (wbc->sync_mode == WB_SYNC_ALL)
3830 tag_pages_for_writeback(mapping, index, end);
3831 while (!done && !nr_to_write_done && (index <= end) &&
3832 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3833 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3834 unsigned i;
3835
3836 scanned = 1;
3837 for (i = 0; i < nr_pages; i++) {
3838 struct page *page = pvec.pages[i];
3839
3840 if (!PagePrivate(page))
3841 continue;
3842
3843 if (!wbc->range_cyclic && page->index > end) {
3844 done = 1;
3845 break;
3846 }
3847
3848 spin_lock(&mapping->private_lock);
3849 if (!PagePrivate(page)) {
3850 spin_unlock(&mapping->private_lock);
3851 continue;
3852 }
3853
3854 eb = (struct extent_buffer *)page->private;
3855
3856 /*
3857 * Shouldn't happen and normally this would be a BUG_ON
3858 * but no sense in crashing the users box for something
3859 * we can survive anyway.
3860 */
3861 if (WARN_ON(!eb)) {
3862 spin_unlock(&mapping->private_lock);
3863 continue;
3864 }
3865
3866 if (eb == prev_eb) {
3867 spin_unlock(&mapping->private_lock);
3868 continue;
3869 }
3870
3871 ret = atomic_inc_not_zero(&eb->refs);
3872 spin_unlock(&mapping->private_lock);
3873 if (!ret)
3874 continue;
3875
3876 prev_eb = eb;
3877 ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
3878 if (!ret) {
3879 free_extent_buffer(eb);
3880 continue;
3881 }
3882
3883 ret = write_one_eb(eb, fs_info, wbc, &epd);
3884 if (ret) {
3885 done = 1;
3886 free_extent_buffer(eb);
3887 break;
3888 }
3889 free_extent_buffer(eb);
3890
3891 /*
3892 * the filesystem may choose to bump up nr_to_write.
3893 * We have to make sure to honor the new nr_to_write
3894 * at any time
3895 */
3896 nr_to_write_done = wbc->nr_to_write <= 0;
3897 }
3898 pagevec_release(&pvec);
3899 cond_resched();
3900 }
3901 if (!scanned && !done) {
3902 /*
3903 * We hit the last page and there is more work to be done: wrap
3904 * back to the start of the file
3905 */
3906 scanned = 1;
3907 index = 0;
3908 goto retry;
3909 }
3910 flush_write_bio(&epd);
3911 return ret;
3912}
3913
3914/**
3915 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3916 * @mapping: address space structure to write
3917 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
3918 * @writepage: function called for each page
3919 * @data: data passed to writepage function
3920 *
3921 * If a page is already under I/O, write_cache_pages() skips it, even
3922 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
3923 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
3924 * and msync() need to guarantee that all the data which was dirty at the time
3925 * the call was made get new I/O started against them. If wbc->sync_mode is
3926 * WB_SYNC_ALL then we were called for data integrity and we must wait for
3927 * existing IO to complete.
3928 */
3929static int extent_write_cache_pages(struct extent_io_tree *tree,
3930 struct address_space *mapping,
3931 struct writeback_control *wbc,
3932 writepage_t writepage, void *data,
3933 void (*flush_fn)(void *))
3934{
3935 struct inode *inode = mapping->host;
3936 int ret = 0;
3937 int done = 0;
3938 int nr_to_write_done = 0;
3939 struct pagevec pvec;
3940 int nr_pages;
3941 pgoff_t index;
3942 pgoff_t end; /* Inclusive */
3943 pgoff_t done_index;
3944 int range_whole = 0;
3945 int scanned = 0;
3946 int tag;
3947
3948 /*
3949 * We have to hold onto the inode so that ordered extents can do their
3950 * work when the IO finishes. The alternative to this is failing to add
3951 * an ordered extent if the igrab() fails there and that is a huge pain
3952 * to deal with, so instead just hold onto the inode throughout the
3953 * writepages operation. If it fails here we are freeing up the inode
3954 * anyway and we'd rather not waste our time writing out stuff that is
3955 * going to be truncated anyway.
3956 */
3957 if (!igrab(inode))
3958 return 0;
3959
3960 pagevec_init(&pvec, 0);
3961 if (wbc->range_cyclic) {
3962 index = mapping->writeback_index; /* Start from prev offset */
3963 end = -1;
3964 } else {
3965 index = wbc->range_start >> PAGE_SHIFT;
3966 end = wbc->range_end >> PAGE_SHIFT;
3967 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
3968 range_whole = 1;
3969 scanned = 1;
3970 }
3971 if (wbc->sync_mode == WB_SYNC_ALL)
3972 tag = PAGECACHE_TAG_TOWRITE;
3973 else
3974 tag = PAGECACHE_TAG_DIRTY;
3975retry:
3976 if (wbc->sync_mode == WB_SYNC_ALL)
3977 tag_pages_for_writeback(mapping, index, end);
3978 done_index = index;
3979 while (!done && !nr_to_write_done && (index <= end) &&
3980 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3981 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3982 unsigned i;
3983
3984 scanned = 1;
3985 for (i = 0; i < nr_pages; i++) {
3986 struct page *page = pvec.pages[i];
3987
3988 done_index = page->index;
3989 /*
3990 * At this point we hold neither mapping->tree_lock nor
3991 * lock on the page itself: the page may be truncated or
3992 * invalidated (changing page->mapping to NULL), or even
3993 * swizzled back from swapper_space to tmpfs file
3994 * mapping
3995 */
3996 if (!trylock_page(page)) {
3997 flush_fn(data);
3998 lock_page(page);
3999 }
4000
4001 if (unlikely(page->mapping != mapping)) {
4002 unlock_page(page);
4003 continue;
4004 }
4005
4006 if (!wbc->range_cyclic && page->index > end) {
4007 done = 1;
4008 unlock_page(page);
4009 continue;
4010 }
4011
4012 if (wbc->sync_mode != WB_SYNC_NONE) {
4013 if (PageWriteback(page))
4014 flush_fn(data);
4015 wait_on_page_writeback(page);
4016 }
4017
4018 if (PageWriteback(page) ||
4019 !clear_page_dirty_for_io(page)) {
4020 unlock_page(page);
4021 continue;
4022 }
4023
4024 ret = (*writepage)(page, wbc, data);
4025
4026 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
4027 unlock_page(page);
4028 ret = 0;
4029 }
4030 if (ret < 0) {
4031 /*
4032 * done_index is set past this page,
4033 * so media errors will not choke
4034 * background writeout for the entire
4035 * file. This has consequences for
4036 * range_cyclic semantics (ie. it may
4037 * not be suitable for data integrity
4038 * writeout).
4039 */
4040 done_index = page->index + 1;
4041 done = 1;
4042 break;
4043 }
4044
4045 /*
4046 * the filesystem may choose to bump up nr_to_write.
4047 * We have to make sure to honor the new nr_to_write
4048 * at any time
4049 */
4050 nr_to_write_done = wbc->nr_to_write <= 0;
4051 }
4052 pagevec_release(&pvec);
4053 cond_resched();
4054 }
4055 if (!scanned && !done) {
4056 /*
4057 * We hit the last page and there is more work to be done: wrap
4058 * back to the start of the file
4059 */
4060 scanned = 1;
4061 index = 0;
4062 goto retry;
4063 }
4064
4065 if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
4066 mapping->writeback_index = done_index;
4067
4068 btrfs_add_delayed_iput(inode);
4069 return ret;
4070}
4071
4072static void flush_epd_write_bio(struct extent_page_data *epd)
4073{
4074 if (epd->bio) {
4075 int ret;
4076
4077 bio_set_op_attrs(epd->bio, REQ_OP_WRITE,
4078 epd->sync_io ? REQ_SYNC : 0);
4079
4080 ret = submit_one_bio(epd->bio, 0, epd->bio_flags);
4081 BUG_ON(ret < 0); /* -ENOMEM */
4082 epd->bio = NULL;
4083 }
4084}
4085
4086static noinline void flush_write_bio(void *data)
4087{
4088 struct extent_page_data *epd = data;
4089 flush_epd_write_bio(epd);
4090}
4091
4092int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
4093 get_extent_t *get_extent,
4094 struct writeback_control *wbc)
4095{
4096 int ret;
4097 struct extent_page_data epd = {
4098 .bio = NULL,
4099 .tree = tree,
4100 .get_extent = get_extent,
4101 .extent_locked = 0,
4102 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4103 .bio_flags = 0,
4104 };
4105
4106 ret = __extent_writepage(page, wbc, &epd);
4107
4108 flush_epd_write_bio(&epd);
4109 return ret;
4110}
4111
4112int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
4113 u64 start, u64 end, get_extent_t *get_extent,
4114 int mode)
4115{
4116 int ret = 0;
4117 struct address_space *mapping = inode->i_mapping;
4118 struct page *page;
4119 unsigned long nr_pages = (end - start + PAGE_SIZE) >>
4120 PAGE_SHIFT;
4121
4122 struct extent_page_data epd = {
4123 .bio = NULL,
4124 .tree = tree,
4125 .get_extent = get_extent,
4126 .extent_locked = 1,
4127 .sync_io = mode == WB_SYNC_ALL,
4128 .bio_flags = 0,
4129 };
4130 struct writeback_control wbc_writepages = {
4131 .sync_mode = mode,
4132 .nr_to_write = nr_pages * 2,
4133 .range_start = start,
4134 .range_end = end + 1,
4135 };
4136
4137 while (start <= end) {
4138 page = find_get_page(mapping, start >> PAGE_SHIFT);
4139 if (clear_page_dirty_for_io(page))
4140 ret = __extent_writepage(page, &wbc_writepages, &epd);
4141 else {
4142 if (tree->ops && tree->ops->writepage_end_io_hook)
4143 tree->ops->writepage_end_io_hook(page, start,
4144 start + PAGE_SIZE - 1,
4145 NULL, 1);
4146 unlock_page(page);
4147 }
4148 put_page(page);
4149 start += PAGE_SIZE;
4150 }
4151
4152 flush_epd_write_bio(&epd);
4153 return ret;
4154}
4155
4156int extent_writepages(struct extent_io_tree *tree,
4157 struct address_space *mapping,
4158 get_extent_t *get_extent,
4159 struct writeback_control *wbc)
4160{
4161 int ret = 0;
4162 struct extent_page_data epd = {
4163 .bio = NULL,
4164 .tree = tree,
4165 .get_extent = get_extent,
4166 .extent_locked = 0,
4167 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4168 .bio_flags = 0,
4169 };
4170
4171 ret = extent_write_cache_pages(tree, mapping, wbc,
4172 __extent_writepage, &epd,
4173 flush_write_bio);
4174 flush_epd_write_bio(&epd);
4175 return ret;
4176}
4177
4178int extent_readpages(struct extent_io_tree *tree,
4179 struct address_space *mapping,
4180 struct list_head *pages, unsigned nr_pages,
4181 get_extent_t get_extent)
4182{
4183 struct bio *bio = NULL;
4184 unsigned page_idx;
4185 unsigned long bio_flags = 0;
4186 struct page *pagepool[16];
4187 struct page *page;
4188 struct extent_map *em_cached = NULL;
4189 int nr = 0;
4190 u64 prev_em_start = (u64)-1;
4191
4192 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
4193 page = list_entry(pages->prev, struct page, lru);
4194
4195 prefetchw(&page->flags);
4196 list_del(&page->lru);
4197 if (add_to_page_cache_lru(page, mapping,
4198 page->index,
4199 readahead_gfp_mask(mapping))) {
4200 put_page(page);
4201 continue;
4202 }
4203
4204 pagepool[nr++] = page;
4205 if (nr < ARRAY_SIZE(pagepool))
4206 continue;
4207 __extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4208 &bio, 0, &bio_flags, &prev_em_start);
4209 nr = 0;
4210 }
4211 if (nr)
4212 __extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4213 &bio, 0, &bio_flags, &prev_em_start);
4214
4215 if (em_cached)
4216 free_extent_map(em_cached);
4217
4218 BUG_ON(!list_empty(pages));
4219 if (bio)
4220 return submit_one_bio(bio, 0, bio_flags);
4221 return 0;
4222}
4223
4224/*
4225 * basic invalidatepage code, this waits on any locked or writeback
4226 * ranges corresponding to the page, and then deletes any extent state
4227 * records from the tree
4228 */
4229int extent_invalidatepage(struct extent_io_tree *tree,
4230 struct page *page, unsigned long offset)
4231{
4232 struct extent_state *cached_state = NULL;
4233 u64 start = page_offset(page);
4234 u64 end = start + PAGE_SIZE - 1;
4235 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
4236
4237 start += ALIGN(offset, blocksize);
4238 if (start > end)
4239 return 0;
4240
4241 lock_extent_bits(tree, start, end, &cached_state);
4242 wait_on_page_writeback(page);
4243 clear_extent_bit(tree, start, end,
4244 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
4245 EXTENT_DO_ACCOUNTING,
4246 1, 1, &cached_state, GFP_NOFS);
4247 return 0;
4248}
4249
4250/*
4251 * a helper for releasepage, this tests for areas of the page that
4252 * are locked or under IO and drops the related state bits if it is safe
4253 * to drop the page.
4254 */
4255static int try_release_extent_state(struct extent_map_tree *map,
4256 struct extent_io_tree *tree,
4257 struct page *page, gfp_t mask)
4258{
4259 u64 start = page_offset(page);
4260 u64 end = start + PAGE_SIZE - 1;
4261 int ret = 1;
4262
4263 if (test_range_bit(tree, start, end,
4264 EXTENT_IOBITS, 0, NULL))
4265 ret = 0;
4266 else {
4267 if ((mask & GFP_NOFS) == GFP_NOFS)
4268 mask = GFP_NOFS;
4269 /*
4270 * at this point we can safely clear everything except the
4271 * locked bit and the nodatasum bit
4272 */
4273 ret = clear_extent_bit(tree, start, end,
4274 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
4275 0, 0, NULL, mask);
4276
4277 /* if clear_extent_bit failed for enomem reasons,
4278 * we can't allow the release to continue.
4279 */
4280 if (ret < 0)
4281 ret = 0;
4282 else
4283 ret = 1;
4284 }
4285 return ret;
4286}
4287
4288/*
4289 * a helper for releasepage. As long as there are no locked extents
4290 * in the range corresponding to the page, both state records and extent
4291 * map records are removed
4292 */
4293int try_release_extent_mapping(struct extent_map_tree *map,
4294 struct extent_io_tree *tree, struct page *page,
4295 gfp_t mask)
4296{
4297 struct extent_map *em;
4298 u64 start = page_offset(page);
4299 u64 end = start + PAGE_SIZE - 1;
4300
4301 if (gfpflags_allow_blocking(mask) &&
4302 page->mapping->host->i_size > SZ_16M) {
4303 u64 len;
4304 while (start <= end) {
4305 len = end - start + 1;
4306 write_lock(&map->lock);
4307 em = lookup_extent_mapping(map, start, len);
4308 if (!em) {
4309 write_unlock(&map->lock);
4310 break;
4311 }
4312 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
4313 em->start != start) {
4314 write_unlock(&map->lock);
4315 free_extent_map(em);
4316 break;
4317 }
4318 if (!test_range_bit(tree, em->start,
4319 extent_map_end(em) - 1,
4320 EXTENT_LOCKED | EXTENT_WRITEBACK,
4321 0, NULL)) {
4322 remove_extent_mapping(map, em);
4323 /* once for the rb tree */
4324 free_extent_map(em);
4325 }
4326 start = extent_map_end(em);
4327 write_unlock(&map->lock);
4328
4329 /* once for us */
4330 free_extent_map(em);
4331 }
4332 }
4333 return try_release_extent_state(map, tree, page, mask);
4334}
4335
4336/*
4337 * helper function for fiemap, which doesn't want to see any holes.
4338 * This maps until we find something past 'last'
4339 */
4340static struct extent_map *get_extent_skip_holes(struct inode *inode,
4341 u64 offset,
4342 u64 last,
4343 get_extent_t *get_extent)
4344{
4345 u64 sectorsize = btrfs_inode_sectorsize(inode);
4346 struct extent_map *em;
4347 u64 len;
4348
4349 if (offset >= last)
4350 return NULL;
4351
4352 while (1) {
4353 len = last - offset;
4354 if (len == 0)
4355 break;
4356 len = ALIGN(len, sectorsize);
4357 em = get_extent(inode, NULL, 0, offset, len, 0);
4358 if (IS_ERR_OR_NULL(em))
4359 return em;
4360
4361 /* if this isn't a hole return it */
4362 if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
4363 em->block_start != EXTENT_MAP_HOLE) {
4364 return em;
4365 }
4366
4367 /* this is a hole, advance to the next extent */
4368 offset = extent_map_end(em);
4369 free_extent_map(em);
4370 if (offset >= last)
4371 break;
4372 }
4373 return NULL;
4374}
4375
4376int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4377 __u64 start, __u64 len, get_extent_t *get_extent)
4378{
4379 int ret = 0;
4380 u64 off = start;
4381 u64 max = start + len;
4382 u32 flags = 0;
4383 u32 found_type;
4384 u64 last;
4385 u64 last_for_get_extent = 0;
4386 u64 disko = 0;
4387 u64 isize = i_size_read(inode);
4388 struct btrfs_key found_key;
4389 struct extent_map *em = NULL;
4390 struct extent_state *cached_state = NULL;
4391 struct btrfs_path *path;
4392 struct btrfs_root *root = BTRFS_I(inode)->root;
4393 int end = 0;
4394 u64 em_start = 0;
4395 u64 em_len = 0;
4396 u64 em_end = 0;
4397
4398 if (len == 0)
4399 return -EINVAL;
4400
4401 path = btrfs_alloc_path();
4402 if (!path)
4403 return -ENOMEM;
4404 path->leave_spinning = 1;
4405
4406 start = round_down(start, btrfs_inode_sectorsize(inode));
4407 len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
4408
4409 /*
4410 * lookup the last file extent. We're not using i_size here
4411 * because there might be preallocation past i_size
4412 */
4413 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode), -1,
4414 0);
4415 if (ret < 0) {
4416 btrfs_free_path(path);
4417 return ret;
4418 } else {
4419 WARN_ON(!ret);
4420 if (ret == 1)
4421 ret = 0;
4422 }
4423
4424 path->slots[0]--;
4425 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
4426 found_type = found_key.type;
4427
4428 /* No extents, but there might be delalloc bits */
4429 if (found_key.objectid != btrfs_ino(inode) ||
4430 found_type != BTRFS_EXTENT_DATA_KEY) {
4431 /* have to trust i_size as the end */
4432 last = (u64)-1;
4433 last_for_get_extent = isize;
4434 } else {
4435 /*
4436 * remember the start of the last extent. There are a
4437 * bunch of different factors that go into the length of the
4438 * extent, so its much less complex to remember where it started
4439 */
4440 last = found_key.offset;
4441 last_for_get_extent = last + 1;
4442 }
4443 btrfs_release_path(path);
4444
4445 /*
4446 * we might have some extents allocated but more delalloc past those
4447 * extents. so, we trust isize unless the start of the last extent is
4448 * beyond isize
4449 */
4450 if (last < isize) {
4451 last = (u64)-1;
4452 last_for_get_extent = isize;
4453 }
4454
4455 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4456 &cached_state);
4457
4458 em = get_extent_skip_holes(inode, start, last_for_get_extent,
4459 get_extent);
4460 if (!em)
4461 goto out;
4462 if (IS_ERR(em)) {
4463 ret = PTR_ERR(em);
4464 goto out;
4465 }
4466
4467 while (!end) {
4468 u64 offset_in_extent = 0;
4469
4470 /* break if the extent we found is outside the range */
4471 if (em->start >= max || extent_map_end(em) < off)
4472 break;
4473
4474 /*
4475 * get_extent may return an extent that starts before our
4476 * requested range. We have to make sure the ranges
4477 * we return to fiemap always move forward and don't
4478 * overlap, so adjust the offsets here
4479 */
4480 em_start = max(em->start, off);
4481
4482 /*
4483 * record the offset from the start of the extent
4484 * for adjusting the disk offset below. Only do this if the
4485 * extent isn't compressed since our in ram offset may be past
4486 * what we have actually allocated on disk.
4487 */
4488 if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4489 offset_in_extent = em_start - em->start;
4490 em_end = extent_map_end(em);
4491 em_len = em_end - em_start;
4492 disko = 0;
4493 flags = 0;
4494
4495 /*
4496 * bump off for our next call to get_extent
4497 */
4498 off = extent_map_end(em);
4499 if (off >= max)
4500 end = 1;
4501
4502 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
4503 end = 1;
4504 flags |= FIEMAP_EXTENT_LAST;
4505 } else if (em->block_start == EXTENT_MAP_INLINE) {
4506 flags |= (FIEMAP_EXTENT_DATA_INLINE |
4507 FIEMAP_EXTENT_NOT_ALIGNED);
4508 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
4509 flags |= (FIEMAP_EXTENT_DELALLOC |
4510 FIEMAP_EXTENT_UNKNOWN);
4511 } else if (fieinfo->fi_extents_max) {
4512 struct btrfs_trans_handle *trans;
4513
4514 u64 bytenr = em->block_start -
4515 (em->start - em->orig_start);
4516
4517 disko = em->block_start + offset_in_extent;
4518
4519 /*
4520 * We need a trans handle to get delayed refs
4521 */
4522 trans = btrfs_join_transaction(root);
4523 /*
4524 * It's OK if we can't start a trans we can still check
4525 * from commit_root
4526 */
4527 if (IS_ERR(trans))
4528 trans = NULL;
4529
4530 /*
4531 * As btrfs supports shared space, this information
4532 * can be exported to userspace tools via
4533 * flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0
4534 * then we're just getting a count and we can skip the
4535 * lookup stuff.
4536 */
4537 ret = btrfs_check_shared(trans, root->fs_info,
4538 root->objectid,
4539 btrfs_ino(inode), bytenr);
4540 if (trans)
4541 btrfs_end_transaction(trans);
4542 if (ret < 0)
4543 goto out_free;
4544 if (ret)
4545 flags |= FIEMAP_EXTENT_SHARED;
4546 ret = 0;
4547 }
4548 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4549 flags |= FIEMAP_EXTENT_ENCODED;
4550 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
4551 flags |= FIEMAP_EXTENT_UNWRITTEN;
4552
4553 free_extent_map(em);
4554 em = NULL;
4555 if ((em_start >= last) || em_len == (u64)-1 ||
4556 (last == (u64)-1 && isize <= em_end)) {
4557 flags |= FIEMAP_EXTENT_LAST;
4558 end = 1;
4559 }
4560
4561 /* now scan forward to see if this is really the last extent. */
4562 em = get_extent_skip_holes(inode, off, last_for_get_extent,
4563 get_extent);
4564 if (IS_ERR(em)) {
4565 ret = PTR_ERR(em);
4566 goto out;
4567 }
4568 if (!em) {
4569 flags |= FIEMAP_EXTENT_LAST;
4570 end = 1;
4571 }
4572 ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
4573 em_len, flags);
4574 if (ret) {
4575 if (ret == 1)
4576 ret = 0;
4577 goto out_free;
4578 }
4579 }
4580out_free:
4581 free_extent_map(em);
4582out:
4583 btrfs_free_path(path);
4584 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4585 &cached_state, GFP_NOFS);
4586 return ret;
4587}
4588
4589static void __free_extent_buffer(struct extent_buffer *eb)
4590{
4591 btrfs_leak_debug_del(&eb->leak_list);
4592 kmem_cache_free(extent_buffer_cache, eb);
4593}
4594
4595int extent_buffer_under_io(struct extent_buffer *eb)
4596{
4597 return (atomic_read(&eb->io_pages) ||
4598 test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
4599 test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4600}
4601
4602/*
4603 * Helper for releasing extent buffer page.
4604 */
4605static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
4606{
4607 unsigned long index;
4608 struct page *page;
4609 int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4610
4611 BUG_ON(extent_buffer_under_io(eb));
4612
4613 index = num_extent_pages(eb->start, eb->len);
4614 if (index == 0)
4615 return;
4616
4617 do {
4618 index--;
4619 page = eb->pages[index];
4620 if (!page)
4621 continue;
4622 if (mapped)
4623 spin_lock(&page->mapping->private_lock);
4624 /*
4625 * We do this since we'll remove the pages after we've
4626 * removed the eb from the radix tree, so we could race
4627 * and have this page now attached to the new eb. So
4628 * only clear page_private if it's still connected to
4629 * this eb.
4630 */
4631 if (PagePrivate(page) &&
4632 page->private == (unsigned long)eb) {
4633 BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4634 BUG_ON(PageDirty(page));
4635 BUG_ON(PageWriteback(page));
4636 /*
4637 * We need to make sure we haven't be attached
4638 * to a new eb.
4639 */
4640 ClearPagePrivate(page);
4641 set_page_private(page, 0);
4642 /* One for the page private */
4643 put_page(page);
4644 }
4645
4646 if (mapped)
4647 spin_unlock(&page->mapping->private_lock);
4648
4649 /* One for when we allocated the page */
4650 put_page(page);
4651 } while (index != 0);
4652}
4653
4654/*
4655 * Helper for releasing the extent buffer.
4656 */
4657static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
4658{
4659 btrfs_release_extent_buffer_page(eb);
4660 __free_extent_buffer(eb);
4661}
4662
4663static struct extent_buffer *
4664__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
4665 unsigned long len)
4666{
4667 struct extent_buffer *eb = NULL;
4668
4669 eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
4670 eb->start = start;
4671 eb->len = len;
4672 eb->fs_info = fs_info;
4673 eb->bflags = 0;
4674 rwlock_init(&eb->lock);
4675 atomic_set(&eb->write_locks, 0);
4676 atomic_set(&eb->read_locks, 0);
4677 atomic_set(&eb->blocking_readers, 0);
4678 atomic_set(&eb->blocking_writers, 0);
4679 atomic_set(&eb->spinning_readers, 0);
4680 atomic_set(&eb->spinning_writers, 0);
4681 eb->lock_nested = 0;
4682 init_waitqueue_head(&eb->write_lock_wq);
4683 init_waitqueue_head(&eb->read_lock_wq);
4684
4685 btrfs_leak_debug_add(&eb->leak_list, &buffers);
4686
4687 spin_lock_init(&eb->refs_lock);
4688 atomic_set(&eb->refs, 1);
4689 atomic_set(&eb->io_pages, 0);
4690
4691 /*
4692 * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
4693 */
4694 BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
4695 > MAX_INLINE_EXTENT_BUFFER_SIZE);
4696 BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
4697
4698 return eb;
4699}
4700
4701struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
4702{
4703 unsigned long i;
4704 struct page *p;
4705 struct extent_buffer *new;
4706 unsigned long num_pages = num_extent_pages(src->start, src->len);
4707
4708 new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
4709 if (new == NULL)
4710 return NULL;
4711
4712 for (i = 0; i < num_pages; i++) {
4713 p = alloc_page(GFP_NOFS);
4714 if (!p) {
4715 btrfs_release_extent_buffer(new);
4716 return NULL;
4717 }
4718 attach_extent_buffer_page(new, p);
4719 WARN_ON(PageDirty(p));
4720 SetPageUptodate(p);
4721 new->pages[i] = p;
4722 copy_page(page_address(p), page_address(src->pages[i]));
4723 }
4724
4725 set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
4726 set_bit(EXTENT_BUFFER_DUMMY, &new->bflags);
4727
4728 return new;
4729}
4730
4731struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4732 u64 start, unsigned long len)
4733{
4734 struct extent_buffer *eb;
4735 unsigned long num_pages;
4736 unsigned long i;
4737
4738 num_pages = num_extent_pages(start, len);
4739
4740 eb = __alloc_extent_buffer(fs_info, start, len);
4741 if (!eb)
4742 return NULL;
4743
4744 for (i = 0; i < num_pages; i++) {
4745 eb->pages[i] = alloc_page(GFP_NOFS);
4746 if (!eb->pages[i])
4747 goto err;
4748 }
4749 set_extent_buffer_uptodate(eb);
4750 btrfs_set_header_nritems(eb, 0);
4751 set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4752
4753 return eb;
4754err:
4755 for (; i > 0; i--)
4756 __free_page(eb->pages[i - 1]);
4757 __free_extent_buffer(eb);
4758 return NULL;
4759}
4760
4761struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4762 u64 start)
4763{
4764 return __alloc_dummy_extent_buffer(fs_info, start, fs_info->nodesize);
4765}
4766
4767static void check_buffer_tree_ref(struct extent_buffer *eb)
4768{
4769 int refs;
4770 /* the ref bit is tricky. We have to make sure it is set
4771 * if we have the buffer dirty. Otherwise the
4772 * code to free a buffer can end up dropping a dirty
4773 * page
4774 *
4775 * Once the ref bit is set, it won't go away while the
4776 * buffer is dirty or in writeback, and it also won't
4777 * go away while we have the reference count on the
4778 * eb bumped.
4779 *
4780 * We can't just set the ref bit without bumping the
4781 * ref on the eb because free_extent_buffer might
4782 * see the ref bit and try to clear it. If this happens
4783 * free_extent_buffer might end up dropping our original
4784 * ref by mistake and freeing the page before we are able
4785 * to add one more ref.
4786 *
4787 * So bump the ref count first, then set the bit. If someone
4788 * beat us to it, drop the ref we added.
4789 */
4790 refs = atomic_read(&eb->refs);
4791 if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4792 return;
4793
4794 spin_lock(&eb->refs_lock);
4795 if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4796 atomic_inc(&eb->refs);
4797 spin_unlock(&eb->refs_lock);
4798}
4799
4800static void mark_extent_buffer_accessed(struct extent_buffer *eb,
4801 struct page *accessed)
4802{
4803 unsigned long num_pages, i;
4804
4805 check_buffer_tree_ref(eb);
4806
4807 num_pages = num_extent_pages(eb->start, eb->len);
4808 for (i = 0; i < num_pages; i++) {
4809 struct page *p = eb->pages[i];
4810
4811 if (p != accessed)
4812 mark_page_accessed(p);
4813 }
4814}
4815
4816struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
4817 u64 start)
4818{
4819 struct extent_buffer *eb;
4820
4821 rcu_read_lock();
4822 eb = radix_tree_lookup(&fs_info->buffer_radix,
4823 start >> PAGE_SHIFT);
4824 if (eb && atomic_inc_not_zero(&eb->refs)) {
4825 rcu_read_unlock();
4826 /*
4827 * Lock our eb's refs_lock to avoid races with
4828 * free_extent_buffer. When we get our eb it might be flagged
4829 * with EXTENT_BUFFER_STALE and another task running
4830 * free_extent_buffer might have seen that flag set,
4831 * eb->refs == 2, that the buffer isn't under IO (dirty and
4832 * writeback flags not set) and it's still in the tree (flag
4833 * EXTENT_BUFFER_TREE_REF set), therefore being in the process
4834 * of decrementing the extent buffer's reference count twice.
4835 * So here we could race and increment the eb's reference count,
4836 * clear its stale flag, mark it as dirty and drop our reference
4837 * before the other task finishes executing free_extent_buffer,
4838 * which would later result in an attempt to free an extent
4839 * buffer that is dirty.
4840 */
4841 if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
4842 spin_lock(&eb->refs_lock);
4843 spin_unlock(&eb->refs_lock);
4844 }
4845 mark_extent_buffer_accessed(eb, NULL);
4846 return eb;
4847 }
4848 rcu_read_unlock();
4849
4850 return NULL;
4851}
4852
4853#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4854struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
4855 u64 start)
4856{
4857 struct extent_buffer *eb, *exists = NULL;
4858 int ret;
4859
4860 eb = find_extent_buffer(fs_info, start);
4861 if (eb)
4862 return eb;
4863 eb = alloc_dummy_extent_buffer(fs_info, start);
4864 if (!eb)
4865 return NULL;
4866 eb->fs_info = fs_info;
4867again:
4868 ret = radix_tree_preload(GFP_NOFS);
4869 if (ret)
4870 goto free_eb;
4871 spin_lock(&fs_info->buffer_lock);
4872 ret = radix_tree_insert(&fs_info->buffer_radix,
4873 start >> PAGE_SHIFT, eb);
4874 spin_unlock(&fs_info->buffer_lock);
4875 radix_tree_preload_end();
4876 if (ret == -EEXIST) {
4877 exists = find_extent_buffer(fs_info, start);
4878 if (exists)
4879 goto free_eb;
4880 else
4881 goto again;
4882 }
4883 check_buffer_tree_ref(eb);
4884 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4885
4886 /*
4887 * We will free dummy extent buffer's if they come into
4888 * free_extent_buffer with a ref count of 2, but if we are using this we
4889 * want the buffers to stay in memory until we're done with them, so
4890 * bump the ref count again.
4891 */
4892 atomic_inc(&eb->refs);
4893 return eb;
4894free_eb:
4895 btrfs_release_extent_buffer(eb);
4896 return exists;
4897}
4898#endif
4899
4900struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4901 u64 start)
4902{
4903 unsigned long len = fs_info->nodesize;
4904 unsigned long num_pages = num_extent_pages(start, len);
4905 unsigned long i;
4906 unsigned long index = start >> PAGE_SHIFT;
4907 struct extent_buffer *eb;
4908 struct extent_buffer *exists = NULL;
4909 struct page *p;
4910 struct address_space *mapping = fs_info->btree_inode->i_mapping;
4911 int uptodate = 1;
4912 int ret;
4913
4914 if (!IS_ALIGNED(start, fs_info->sectorsize)) {
4915 btrfs_err(fs_info, "bad tree block start %llu", start);
4916 return ERR_PTR(-EINVAL);
4917 }
4918
4919 eb = find_extent_buffer(fs_info, start);
4920 if (eb)
4921 return eb;
4922
4923 eb = __alloc_extent_buffer(fs_info, start, len);
4924 if (!eb)
4925 return ERR_PTR(-ENOMEM);
4926
4927 for (i = 0; i < num_pages; i++, index++) {
4928 p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
4929 if (!p) {
4930 exists = ERR_PTR(-ENOMEM);
4931 goto free_eb;
4932 }
4933
4934 spin_lock(&mapping->private_lock);
4935 if (PagePrivate(p)) {
4936 /*
4937 * We could have already allocated an eb for this page
4938 * and attached one so lets see if we can get a ref on
4939 * the existing eb, and if we can we know it's good and
4940 * we can just return that one, else we know we can just
4941 * overwrite page->private.
4942 */
4943 exists = (struct extent_buffer *)p->private;
4944 if (atomic_inc_not_zero(&exists->refs)) {
4945 spin_unlock(&mapping->private_lock);
4946 unlock_page(p);
4947 put_page(p);
4948 mark_extent_buffer_accessed(exists, p);
4949 goto free_eb;
4950 }
4951 exists = NULL;
4952
4953 /*
4954 * Do this so attach doesn't complain and we need to
4955 * drop the ref the old guy had.
4956 */
4957 ClearPagePrivate(p);
4958 WARN_ON(PageDirty(p));
4959 put_page(p);
4960 }
4961 attach_extent_buffer_page(eb, p);
4962 spin_unlock(&mapping->private_lock);
4963 WARN_ON(PageDirty(p));
4964 eb->pages[i] = p;
4965 if (!PageUptodate(p))
4966 uptodate = 0;
4967
4968 /*
4969 * see below about how we avoid a nasty race with release page
4970 * and why we unlock later
4971 */
4972 }
4973 if (uptodate)
4974 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4975again:
4976 ret = radix_tree_preload(GFP_NOFS);
4977 if (ret) {
4978 exists = ERR_PTR(ret);
4979 goto free_eb;
4980 }
4981
4982 spin_lock(&fs_info->buffer_lock);
4983 ret = radix_tree_insert(&fs_info->buffer_radix,
4984 start >> PAGE_SHIFT, eb);
4985 spin_unlock(&fs_info->buffer_lock);
4986 radix_tree_preload_end();
4987 if (ret == -EEXIST) {
4988 exists = find_extent_buffer(fs_info, start);
4989 if (exists)
4990 goto free_eb;
4991 else
4992 goto again;
4993 }
4994 /* add one reference for the tree */
4995 check_buffer_tree_ref(eb);
4996 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4997
4998 /*
4999 * there is a race where release page may have
5000 * tried to find this extent buffer in the radix
5001 * but failed. It will tell the VM it is safe to
5002 * reclaim the, and it will clear the page private bit.
5003 * We must make sure to set the page private bit properly
5004 * after the extent buffer is in the radix tree so
5005 * it doesn't get lost
5006 */
5007 SetPageChecked(eb->pages[0]);
5008 for (i = 1; i < num_pages; i++) {
5009 p = eb->pages[i];
5010 ClearPageChecked(p);
5011 unlock_page(p);
5012 }
5013 unlock_page(eb->pages[0]);
5014 return eb;
5015
5016free_eb:
5017 WARN_ON(!atomic_dec_and_test(&eb->refs));
5018 for (i = 0; i < num_pages; i++) {
5019 if (eb->pages[i])
5020 unlock_page(eb->pages[i]);
5021 }
5022
5023 btrfs_release_extent_buffer(eb);
5024 return exists;
5025}
5026
5027static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
5028{
5029 struct extent_buffer *eb =
5030 container_of(head, struct extent_buffer, rcu_head);
5031
5032 __free_extent_buffer(eb);
5033}
5034
5035/* Expects to have eb->eb_lock already held */
5036static int release_extent_buffer(struct extent_buffer *eb)
5037{
5038 WARN_ON(atomic_read(&eb->refs) == 0);
5039 if (atomic_dec_and_test(&eb->refs)) {
5040 if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
5041 struct btrfs_fs_info *fs_info = eb->fs_info;
5042
5043 spin_unlock(&eb->refs_lock);
5044
5045 spin_lock(&fs_info->buffer_lock);
5046 radix_tree_delete(&fs_info->buffer_radix,
5047 eb->start >> PAGE_SHIFT);
5048 spin_unlock(&fs_info->buffer_lock);
5049 } else {
5050 spin_unlock(&eb->refs_lock);
5051 }
5052
5053 /* Should be safe to release our pages at this point */
5054 btrfs_release_extent_buffer_page(eb);
5055#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5056 if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))) {
5057 __free_extent_buffer(eb);
5058 return 1;
5059 }
5060#endif
5061 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
5062 return 1;
5063 }
5064 spin_unlock(&eb->refs_lock);
5065
5066 return 0;
5067}
5068
5069void free_extent_buffer(struct extent_buffer *eb)
5070{
5071 int refs;
5072 int old;
5073 if (!eb)
5074 return;
5075
5076 while (1) {
5077 refs = atomic_read(&eb->refs);
5078 if (refs <= 3)
5079 break;
5080 old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
5081 if (old == refs)
5082 return;
5083 }
5084
5085 spin_lock(&eb->refs_lock);
5086 if (atomic_read(&eb->refs) == 2 &&
5087 test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
5088 atomic_dec(&eb->refs);
5089
5090 if (atomic_read(&eb->refs) == 2 &&
5091 test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
5092 !extent_buffer_under_io(eb) &&
5093 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5094 atomic_dec(&eb->refs);
5095
5096 /*
5097 * I know this is terrible, but it's temporary until we stop tracking
5098 * the uptodate bits and such for the extent buffers.
5099 */
5100 release_extent_buffer(eb);
5101}
5102
5103void free_extent_buffer_stale(struct extent_buffer *eb)
5104{
5105 if (!eb)
5106 return;
5107
5108 spin_lock(&eb->refs_lock);
5109 set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
5110
5111 if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
5112 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5113 atomic_dec(&eb->refs);
5114 release_extent_buffer(eb);
5115}
5116
5117void clear_extent_buffer_dirty(struct extent_buffer *eb)
5118{
5119 unsigned long i;
5120 unsigned long num_pages;
5121 struct page *page;
5122
5123 num_pages = num_extent_pages(eb->start, eb->len);
5124
5125 for (i = 0; i < num_pages; i++) {
5126 page = eb->pages[i];
5127 if (!PageDirty(page))
5128 continue;
5129
5130 lock_page(page);
5131 WARN_ON(!PagePrivate(page));
5132
5133 clear_page_dirty_for_io(page);
5134 spin_lock_irq(&page->mapping->tree_lock);
5135 if (!PageDirty(page)) {
5136 radix_tree_tag_clear(&page->mapping->page_tree,
5137 page_index(page),
5138 PAGECACHE_TAG_DIRTY);
5139 }
5140 spin_unlock_irq(&page->mapping->tree_lock);
5141 ClearPageError(page);
5142 unlock_page(page);
5143 }
5144 WARN_ON(atomic_read(&eb->refs) == 0);
5145}
5146
5147int set_extent_buffer_dirty(struct extent_buffer *eb)
5148{
5149 unsigned long i;
5150 unsigned long num_pages;
5151 int was_dirty = 0;
5152
5153 check_buffer_tree_ref(eb);
5154
5155 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
5156
5157 num_pages = num_extent_pages(eb->start, eb->len);
5158 WARN_ON(atomic_read(&eb->refs) == 0);
5159 WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
5160
5161 for (i = 0; i < num_pages; i++)
5162 set_page_dirty(eb->pages[i]);
5163 return was_dirty;
5164}
5165
5166void clear_extent_buffer_uptodate(struct extent_buffer *eb)
5167{
5168 unsigned long i;
5169 struct page *page;
5170 unsigned long num_pages;
5171
5172 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5173 num_pages = num_extent_pages(eb->start, eb->len);
5174 for (i = 0; i < num_pages; i++) {
5175 page = eb->pages[i];
5176 if (page)
5177 ClearPageUptodate(page);
5178 }
5179}
5180
5181void set_extent_buffer_uptodate(struct extent_buffer *eb)
5182{
5183 unsigned long i;
5184 struct page *page;
5185 unsigned long num_pages;
5186
5187 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5188 num_pages = num_extent_pages(eb->start, eb->len);
5189 for (i = 0; i < num_pages; i++) {
5190 page = eb->pages[i];
5191 SetPageUptodate(page);
5192 }
5193}
5194
5195int extent_buffer_uptodate(struct extent_buffer *eb)
5196{
5197 return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5198}
5199
5200int read_extent_buffer_pages(struct extent_io_tree *tree,
5201 struct extent_buffer *eb, int wait,
5202 get_extent_t *get_extent, int mirror_num)
5203{
5204 unsigned long i;
5205 struct page *page;
5206 int err;
5207 int ret = 0;
5208 int locked_pages = 0;
5209 int all_uptodate = 1;
5210 unsigned long num_pages;
5211 unsigned long num_reads = 0;
5212 struct bio *bio = NULL;
5213 unsigned long bio_flags = 0;
5214
5215 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
5216 return 0;
5217
5218 num_pages = num_extent_pages(eb->start, eb->len);
5219 for (i = 0; i < num_pages; i++) {
5220 page = eb->pages[i];
5221 if (wait == WAIT_NONE) {
5222 if (!trylock_page(page))
5223 goto unlock_exit;
5224 } else {
5225 lock_page(page);
5226 }
5227 locked_pages++;
5228 }
5229 /*
5230 * We need to firstly lock all pages to make sure that
5231 * the uptodate bit of our pages won't be affected by
5232 * clear_extent_buffer_uptodate().
5233 */
5234 for (i = 0; i < num_pages; i++) {
5235 page = eb->pages[i];
5236 if (!PageUptodate(page)) {
5237 num_reads++;
5238 all_uptodate = 0;
5239 }
5240 }
5241
5242 if (all_uptodate) {
5243 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5244 goto unlock_exit;
5245 }
5246
5247 clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
5248 eb->read_mirror = 0;
5249 atomic_set(&eb->io_pages, num_reads);
5250 for (i = 0; i < num_pages; i++) {
5251 page = eb->pages[i];
5252
5253 if (!PageUptodate(page)) {
5254 if (ret) {
5255 atomic_dec(&eb->io_pages);
5256 unlock_page(page);
5257 continue;
5258 }
5259
5260 ClearPageError(page);
5261 err = __extent_read_full_page(tree, page,
5262 get_extent, &bio,
5263 mirror_num, &bio_flags,
5264 REQ_META);
5265 if (err) {
5266 ret = err;
5267 /*
5268 * We use &bio in above __extent_read_full_page,
5269 * so we ensure that if it returns error, the
5270 * current page fails to add itself to bio and
5271 * it's been unlocked.
5272 *
5273 * We must dec io_pages by ourselves.
5274 */
5275 atomic_dec(&eb->io_pages);
5276 }
5277 } else {
5278 unlock_page(page);
5279 }
5280 }
5281
5282 if (bio) {
5283 err = submit_one_bio(bio, mirror_num, bio_flags);
5284 if (err)
5285 return err;
5286 }
5287
5288 if (ret || wait != WAIT_COMPLETE)
5289 return ret;
5290
5291 for (i = 0; i < num_pages; i++) {
5292 page = eb->pages[i];
5293 wait_on_page_locked(page);
5294 if (!PageUptodate(page))
5295 ret = -EIO;
5296 }
5297
5298 return ret;
5299
5300unlock_exit:
5301 while (locked_pages > 0) {
5302 locked_pages--;
5303 page = eb->pages[locked_pages];
5304 unlock_page(page);
5305 }
5306 return ret;
5307}
5308
5309void read_extent_buffer(struct extent_buffer *eb, void *dstv,
5310 unsigned long start,
5311 unsigned long len)
5312{
5313 size_t cur;
5314 size_t offset;
5315 struct page *page;
5316 char *kaddr;
5317 char *dst = (char *)dstv;
5318 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5319 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5320
5321 WARN_ON(start > eb->len);
5322 WARN_ON(start + len > eb->start + eb->len);
5323
5324 offset = (start_offset + start) & (PAGE_SIZE - 1);
5325
5326 while (len > 0) {
5327 page = eb->pages[i];
5328
5329 cur = min(len, (PAGE_SIZE - offset));
5330 kaddr = page_address(page);
5331 memcpy(dst, kaddr + offset, cur);
5332
5333 dst += cur;
5334 len -= cur;
5335 offset = 0;
5336 i++;
5337 }
5338}
5339
5340int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
5341 unsigned long start,
5342 unsigned long len)
5343{
5344 size_t cur;
5345 size_t offset;
5346 struct page *page;
5347 char *kaddr;
5348 char __user *dst = (char __user *)dstv;
5349 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5350 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5351 int ret = 0;
5352
5353 WARN_ON(start > eb->len);
5354 WARN_ON(start + len > eb->start + eb->len);
5355
5356 offset = (start_offset + start) & (PAGE_SIZE - 1);
5357
5358 while (len > 0) {
5359 page = eb->pages[i];
5360
5361 cur = min(len, (PAGE_SIZE - offset));
5362 kaddr = page_address(page);
5363 if (copy_to_user(dst, kaddr + offset, cur)) {
5364 ret = -EFAULT;
5365 break;
5366 }
5367
5368 dst += cur;
5369 len -= cur;
5370 offset = 0;
5371 i++;
5372 }
5373
5374 return ret;
5375}
5376
5377/*
5378 * return 0 if the item is found within a page.
5379 * return 1 if the item spans two pages.
5380 * return -EINVAL otherwise.
5381 */
5382int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
5383 unsigned long min_len, char **map,
5384 unsigned long *map_start,
5385 unsigned long *map_len)
5386{
5387 size_t offset = start & (PAGE_SIZE - 1);
5388 char *kaddr;
5389 struct page *p;
5390 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5391 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5392 unsigned long end_i = (start_offset + start + min_len - 1) >>
5393 PAGE_SHIFT;
5394
5395 if (i != end_i)
5396 return 1;
5397
5398 if (i == 0) {
5399 offset = start_offset;
5400 *map_start = 0;
5401 } else {
5402 offset = 0;
5403 *map_start = ((u64)i << PAGE_SHIFT) - start_offset;
5404 }
5405
5406 if (start + min_len > eb->len) {
5407 WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
5408 eb->start, eb->len, start, min_len);
5409 return -EINVAL;
5410 }
5411
5412 p = eb->pages[i];
5413 kaddr = page_address(p);
5414 *map = kaddr + offset;
5415 *map_len = PAGE_SIZE - offset;
5416 return 0;
5417}
5418
5419int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
5420 unsigned long start,
5421 unsigned long len)
5422{
5423 size_t cur;
5424 size_t offset;
5425 struct page *page;
5426 char *kaddr;
5427 char *ptr = (char *)ptrv;
5428 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5429 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5430 int ret = 0;
5431
5432 WARN_ON(start > eb->len);
5433 WARN_ON(start + len > eb->start + eb->len);
5434
5435 offset = (start_offset + start) & (PAGE_SIZE - 1);
5436
5437 while (len > 0) {
5438 page = eb->pages[i];
5439
5440 cur = min(len, (PAGE_SIZE - offset));
5441
5442 kaddr = page_address(page);
5443 ret = memcmp(ptr, kaddr + offset, cur);
5444 if (ret)
5445 break;
5446
5447 ptr += cur;
5448 len -= cur;
5449 offset = 0;
5450 i++;
5451 }
5452 return ret;
5453}
5454
5455void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
5456 const void *srcv)
5457{
5458 char *kaddr;
5459
5460 WARN_ON(!PageUptodate(eb->pages[0]));
5461 kaddr = page_address(eb->pages[0]);
5462 memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,
5463 BTRFS_FSID_SIZE);
5464}
5465
5466void write_extent_buffer_fsid(struct extent_buffer *eb, const void *srcv)
5467{
5468 char *kaddr;
5469
5470 WARN_ON(!PageUptodate(eb->pages[0]));
5471 kaddr = page_address(eb->pages[0]);
5472 memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,
5473 BTRFS_FSID_SIZE);
5474}
5475
5476void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
5477 unsigned long start, unsigned long len)
5478{
5479 size_t cur;
5480 size_t offset;
5481 struct page *page;
5482 char *kaddr;
5483 char *src = (char *)srcv;
5484 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5485 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5486
5487 WARN_ON(start > eb->len);
5488 WARN_ON(start + len > eb->start + eb->len);
5489
5490 offset = (start_offset + start) & (PAGE_SIZE - 1);
5491
5492 while (len > 0) {
5493 page = eb->pages[i];
5494 WARN_ON(!PageUptodate(page));
5495
5496 cur = min(len, PAGE_SIZE - offset);
5497 kaddr = page_address(page);
5498 memcpy(kaddr + offset, src, cur);
5499
5500 src += cur;
5501 len -= cur;
5502 offset = 0;
5503 i++;
5504 }
5505}
5506
5507void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
5508 unsigned long len)
5509{
5510 size_t cur;
5511 size_t offset;
5512 struct page *page;
5513 char *kaddr;
5514 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5515 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5516
5517 WARN_ON(start > eb->len);
5518 WARN_ON(start + len > eb->start + eb->len);
5519
5520 offset = (start_offset + start) & (PAGE_SIZE - 1);
5521
5522 while (len > 0) {
5523 page = eb->pages[i];
5524 WARN_ON(!PageUptodate(page));
5525
5526 cur = min(len, PAGE_SIZE - offset);
5527 kaddr = page_address(page);
5528 memset(kaddr + offset, 0, cur);
5529
5530 len -= cur;
5531 offset = 0;
5532 i++;
5533 }
5534}
5535
5536void copy_extent_buffer_full(struct extent_buffer *dst,
5537 struct extent_buffer *src)
5538{
5539 int i;
5540 unsigned num_pages;
5541
5542 ASSERT(dst->len == src->len);
5543
5544 num_pages = num_extent_pages(dst->start, dst->len);
5545 for (i = 0; i < num_pages; i++)
5546 copy_page(page_address(dst->pages[i]),
5547 page_address(src->pages[i]));
5548}
5549
5550void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
5551 unsigned long dst_offset, unsigned long src_offset,
5552 unsigned long len)
5553{
5554 u64 dst_len = dst->len;
5555 size_t cur;
5556 size_t offset;
5557 struct page *page;
5558 char *kaddr;
5559 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5560 unsigned long i = (start_offset + dst_offset) >> PAGE_SHIFT;
5561
5562 WARN_ON(src->len != dst_len);
5563
5564 offset = (start_offset + dst_offset) &
5565 (PAGE_SIZE - 1);
5566
5567 while (len > 0) {
5568 page = dst->pages[i];
5569 WARN_ON(!PageUptodate(page));
5570
5571 cur = min(len, (unsigned long)(PAGE_SIZE - offset));
5572
5573 kaddr = page_address(page);
5574 read_extent_buffer(src, kaddr + offset, src_offset, cur);
5575
5576 src_offset += cur;
5577 len -= cur;
5578 offset = 0;
5579 i++;
5580 }
5581}
5582
5583void le_bitmap_set(u8 *map, unsigned int start, int len)
5584{
5585 u8 *p = map + BIT_BYTE(start);
5586 const unsigned int size = start + len;
5587 int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
5588 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
5589
5590 while (len - bits_to_set >= 0) {
5591 *p |= mask_to_set;
5592 len -= bits_to_set;
5593 bits_to_set = BITS_PER_BYTE;
5594 mask_to_set = ~0;
5595 p++;
5596 }
5597 if (len) {
5598 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5599 *p |= mask_to_set;
5600 }
5601}
5602
5603void le_bitmap_clear(u8 *map, unsigned int start, int len)
5604{
5605 u8 *p = map + BIT_BYTE(start);
5606 const unsigned int size = start + len;
5607 int bits_to_clear = BITS_PER_BYTE - (start % BITS_PER_BYTE);
5608 u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(start);
5609
5610 while (len - bits_to_clear >= 0) {
5611 *p &= ~mask_to_clear;
5612 len -= bits_to_clear;
5613 bits_to_clear = BITS_PER_BYTE;
5614 mask_to_clear = ~0;
5615 p++;
5616 }
5617 if (len) {
5618 mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5619 *p &= ~mask_to_clear;
5620 }
5621}
5622
5623/*
5624 * eb_bitmap_offset() - calculate the page and offset of the byte containing the
5625 * given bit number
5626 * @eb: the extent buffer
5627 * @start: offset of the bitmap item in the extent buffer
5628 * @nr: bit number
5629 * @page_index: return index of the page in the extent buffer that contains the
5630 * given bit number
5631 * @page_offset: return offset into the page given by page_index
5632 *
5633 * This helper hides the ugliness of finding the byte in an extent buffer which
5634 * contains a given bit.
5635 */
5636static inline void eb_bitmap_offset(struct extent_buffer *eb,
5637 unsigned long start, unsigned long nr,
5638 unsigned long *page_index,
5639 size_t *page_offset)
5640{
5641 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5642 size_t byte_offset = BIT_BYTE(nr);
5643 size_t offset;
5644
5645 /*
5646 * The byte we want is the offset of the extent buffer + the offset of
5647 * the bitmap item in the extent buffer + the offset of the byte in the
5648 * bitmap item.
5649 */
5650 offset = start_offset + start + byte_offset;
5651
5652 *page_index = offset >> PAGE_SHIFT;
5653 *page_offset = offset & (PAGE_SIZE - 1);
5654}
5655
5656/**
5657 * extent_buffer_test_bit - determine whether a bit in a bitmap item is set
5658 * @eb: the extent buffer
5659 * @start: offset of the bitmap item in the extent buffer
5660 * @nr: bit number to test
5661 */
5662int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
5663 unsigned long nr)
5664{
5665 u8 *kaddr;
5666 struct page *page;
5667 unsigned long i;
5668 size_t offset;
5669
5670 eb_bitmap_offset(eb, start, nr, &i, &offset);
5671 page = eb->pages[i];
5672 WARN_ON(!PageUptodate(page));
5673 kaddr = page_address(page);
5674 return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
5675}
5676
5677/**
5678 * extent_buffer_bitmap_set - set an area of a bitmap
5679 * @eb: the extent buffer
5680 * @start: offset of the bitmap item in the extent buffer
5681 * @pos: bit number of the first bit
5682 * @len: number of bits to set
5683 */
5684void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
5685 unsigned long pos, unsigned long len)
5686{
5687 u8 *kaddr;
5688 struct page *page;
5689 unsigned long i;
5690 size_t offset;
5691 const unsigned int size = pos + len;
5692 int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5693 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
5694
5695 eb_bitmap_offset(eb, start, pos, &i, &offset);
5696 page = eb->pages[i];
5697 WARN_ON(!PageUptodate(page));
5698 kaddr = page_address(page);
5699
5700 while (len >= bits_to_set) {
5701 kaddr[offset] |= mask_to_set;
5702 len -= bits_to_set;
5703 bits_to_set = BITS_PER_BYTE;
5704 mask_to_set = ~0;
5705 if (++offset >= PAGE_SIZE && len > 0) {
5706 offset = 0;
5707 page = eb->pages[++i];
5708 WARN_ON(!PageUptodate(page));
5709 kaddr = page_address(page);
5710 }
5711 }
5712 if (len) {
5713 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5714 kaddr[offset] |= mask_to_set;
5715 }
5716}
5717
5718
5719/**
5720 * extent_buffer_bitmap_clear - clear an area of a bitmap
5721 * @eb: the extent buffer
5722 * @start: offset of the bitmap item in the extent buffer
5723 * @pos: bit number of the first bit
5724 * @len: number of bits to clear
5725 */
5726void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
5727 unsigned long pos, unsigned long len)
5728{
5729 u8 *kaddr;
5730 struct page *page;
5731 unsigned long i;
5732 size_t offset;
5733 const unsigned int size = pos + len;
5734 int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5735 u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
5736
5737 eb_bitmap_offset(eb, start, pos, &i, &offset);
5738 page = eb->pages[i];
5739 WARN_ON(!PageUptodate(page));
5740 kaddr = page_address(page);
5741
5742 while (len >= bits_to_clear) {
5743 kaddr[offset] &= ~mask_to_clear;
5744 len -= bits_to_clear;
5745 bits_to_clear = BITS_PER_BYTE;
5746 mask_to_clear = ~0;
5747 if (++offset >= PAGE_SIZE && len > 0) {
5748 offset = 0;
5749 page = eb->pages[++i];
5750 WARN_ON(!PageUptodate(page));
5751 kaddr = page_address(page);
5752 }
5753 }
5754 if (len) {
5755 mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5756 kaddr[offset] &= ~mask_to_clear;
5757 }
5758}
5759
5760static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
5761{
5762 unsigned long distance = (src > dst) ? src - dst : dst - src;
5763 return distance < len;
5764}
5765
5766static void copy_pages(struct page *dst_page, struct page *src_page,
5767 unsigned long dst_off, unsigned long src_off,
5768 unsigned long len)
5769{
5770 char *dst_kaddr = page_address(dst_page);
5771 char *src_kaddr;
5772 int must_memmove = 0;
5773
5774 if (dst_page != src_page) {
5775 src_kaddr = page_address(src_page);
5776 } else {
5777 src_kaddr = dst_kaddr;
5778 if (areas_overlap(src_off, dst_off, len))
5779 must_memmove = 1;
5780 }
5781
5782 if (must_memmove)
5783 memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
5784 else
5785 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5786}
5787
5788void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5789 unsigned long src_offset, unsigned long len)
5790{
5791 struct btrfs_fs_info *fs_info = dst->fs_info;
5792 size_t cur;
5793 size_t dst_off_in_page;
5794 size_t src_off_in_page;
5795 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5796 unsigned long dst_i;
5797 unsigned long src_i;
5798
5799 if (src_offset + len > dst->len) {
5800 btrfs_err(fs_info,
5801 "memmove bogus src_offset %lu move len %lu dst len %lu",
5802 src_offset, len, dst->len);
5803 BUG_ON(1);
5804 }
5805 if (dst_offset + len > dst->len) {
5806 btrfs_err(fs_info,
5807 "memmove bogus dst_offset %lu move len %lu dst len %lu",
5808 dst_offset, len, dst->len);
5809 BUG_ON(1);
5810 }
5811
5812 while (len > 0) {
5813 dst_off_in_page = (start_offset + dst_offset) &
5814 (PAGE_SIZE - 1);
5815 src_off_in_page = (start_offset + src_offset) &
5816 (PAGE_SIZE - 1);
5817
5818 dst_i = (start_offset + dst_offset) >> PAGE_SHIFT;
5819 src_i = (start_offset + src_offset) >> PAGE_SHIFT;
5820
5821 cur = min(len, (unsigned long)(PAGE_SIZE -
5822 src_off_in_page));
5823 cur = min_t(unsigned long, cur,
5824 (unsigned long)(PAGE_SIZE - dst_off_in_page));
5825
5826 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5827 dst_off_in_page, src_off_in_page, cur);
5828
5829 src_offset += cur;
5830 dst_offset += cur;
5831 len -= cur;
5832 }
5833}
5834
5835void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5836 unsigned long src_offset, unsigned long len)
5837{
5838 struct btrfs_fs_info *fs_info = dst->fs_info;
5839 size_t cur;
5840 size_t dst_off_in_page;
5841 size_t src_off_in_page;
5842 unsigned long dst_end = dst_offset + len - 1;
5843 unsigned long src_end = src_offset + len - 1;
5844 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5845 unsigned long dst_i;
5846 unsigned long src_i;
5847
5848 if (src_offset + len > dst->len) {
5849 btrfs_err(fs_info,
5850 "memmove bogus src_offset %lu move len %lu len %lu",
5851 src_offset, len, dst->len);
5852 BUG_ON(1);
5853 }
5854 if (dst_offset + len > dst->len) {
5855 btrfs_err(fs_info,
5856 "memmove bogus dst_offset %lu move len %lu len %lu",
5857 dst_offset, len, dst->len);
5858 BUG_ON(1);
5859 }
5860 if (dst_offset < src_offset) {
5861 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
5862 return;
5863 }
5864 while (len > 0) {
5865 dst_i = (start_offset + dst_end) >> PAGE_SHIFT;
5866 src_i = (start_offset + src_end) >> PAGE_SHIFT;
5867
5868 dst_off_in_page = (start_offset + dst_end) &
5869 (PAGE_SIZE - 1);
5870 src_off_in_page = (start_offset + src_end) &
5871 (PAGE_SIZE - 1);
5872
5873 cur = min_t(unsigned long, len, src_off_in_page + 1);
5874 cur = min(cur, dst_off_in_page + 1);
5875 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5876 dst_off_in_page - cur + 1,
5877 src_off_in_page - cur + 1, cur);
5878
5879 dst_end -= cur;
5880 src_end -= cur;
5881 len -= cur;
5882 }
5883}
5884
5885int try_release_extent_buffer(struct page *page)
5886{
5887 struct extent_buffer *eb;
5888
5889 /*
5890 * We need to make sure nobody is attaching this page to an eb right
5891 * now.
5892 */
5893 spin_lock(&page->mapping->private_lock);
5894 if (!PagePrivate(page)) {
5895 spin_unlock(&page->mapping->private_lock);
5896 return 1;
5897 }
5898
5899 eb = (struct extent_buffer *)page->private;
5900 BUG_ON(!eb);
5901
5902 /*
5903 * This is a little awful but should be ok, we need to make sure that
5904 * the eb doesn't disappear out from under us while we're looking at
5905 * this page.
5906 */
5907 spin_lock(&eb->refs_lock);
5908 if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5909 spin_unlock(&eb->refs_lock);
5910 spin_unlock(&page->mapping->private_lock);
5911 return 0;
5912 }
5913 spin_unlock(&page->mapping->private_lock);
5914
5915 /*
5916 * If tree ref isn't set then we know the ref on this eb is a real ref,
5917 * so just return, this page will likely be freed soon anyway.
5918 */
5919 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
5920 spin_unlock(&eb->refs_lock);
5921 return 0;
5922 }
5923
5924 return release_extent_buffer(eb);
5925}