Loading...
1#include <linux/bitops.h>
2#include <linux/slab.h>
3#include <linux/bio.h>
4#include <linux/mm.h>
5#include <linux/pagemap.h>
6#include <linux/page-flags.h>
7#include <linux/module.h>
8#include <linux/spinlock.h>
9#include <linux/blkdev.h>
10#include <linux/swap.h>
11#include <linux/writeback.h>
12#include <linux/pagevec.h>
13#include <linux/prefetch.h>
14#include <linux/cleancache.h>
15#include "extent_io.h"
16#include "extent_map.h"
17#include "compat.h"
18#include "ctree.h"
19#include "btrfs_inode.h"
20
21static struct kmem_cache *extent_state_cache;
22static struct kmem_cache *extent_buffer_cache;
23
24static LIST_HEAD(buffers);
25static LIST_HEAD(states);
26
27#define LEAK_DEBUG 0
28#if LEAK_DEBUG
29static DEFINE_SPINLOCK(leak_lock);
30#endif
31
32#define BUFFER_LRU_MAX 64
33
34struct tree_entry {
35 u64 start;
36 u64 end;
37 struct rb_node rb_node;
38};
39
40struct extent_page_data {
41 struct bio *bio;
42 struct extent_io_tree *tree;
43 get_extent_t *get_extent;
44
45 /* tells writepage not to lock the state bits for this range
46 * it still does the unlocking
47 */
48 unsigned int extent_locked:1;
49
50 /* tells the submit_bio code to use a WRITE_SYNC */
51 unsigned int sync_io:1;
52};
53
54int __init extent_io_init(void)
55{
56 extent_state_cache = kmem_cache_create("extent_state",
57 sizeof(struct extent_state), 0,
58 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
59 if (!extent_state_cache)
60 return -ENOMEM;
61
62 extent_buffer_cache = kmem_cache_create("extent_buffers",
63 sizeof(struct extent_buffer), 0,
64 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
65 if (!extent_buffer_cache)
66 goto free_state_cache;
67 return 0;
68
69free_state_cache:
70 kmem_cache_destroy(extent_state_cache);
71 return -ENOMEM;
72}
73
74void extent_io_exit(void)
75{
76 struct extent_state *state;
77 struct extent_buffer *eb;
78
79 while (!list_empty(&states)) {
80 state = list_entry(states.next, struct extent_state, leak_list);
81 printk(KERN_ERR "btrfs state leak: start %llu end %llu "
82 "state %lu in tree %p refs %d\n",
83 (unsigned long long)state->start,
84 (unsigned long long)state->end,
85 state->state, state->tree, atomic_read(&state->refs));
86 list_del(&state->leak_list);
87 kmem_cache_free(extent_state_cache, state);
88
89 }
90
91 while (!list_empty(&buffers)) {
92 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
93 printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
94 "refs %d\n", (unsigned long long)eb->start,
95 eb->len, atomic_read(&eb->refs));
96 list_del(&eb->leak_list);
97 kmem_cache_free(extent_buffer_cache, eb);
98 }
99 if (extent_state_cache)
100 kmem_cache_destroy(extent_state_cache);
101 if (extent_buffer_cache)
102 kmem_cache_destroy(extent_buffer_cache);
103}
104
105void extent_io_tree_init(struct extent_io_tree *tree,
106 struct address_space *mapping)
107{
108 tree->state = RB_ROOT;
109 INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
110 tree->ops = NULL;
111 tree->dirty_bytes = 0;
112 spin_lock_init(&tree->lock);
113 spin_lock_init(&tree->buffer_lock);
114 tree->mapping = mapping;
115}
116
117static struct extent_state *alloc_extent_state(gfp_t mask)
118{
119 struct extent_state *state;
120#if LEAK_DEBUG
121 unsigned long flags;
122#endif
123
124 state = kmem_cache_alloc(extent_state_cache, mask);
125 if (!state)
126 return state;
127 state->state = 0;
128 state->private = 0;
129 state->tree = NULL;
130#if LEAK_DEBUG
131 spin_lock_irqsave(&leak_lock, flags);
132 list_add(&state->leak_list, &states);
133 spin_unlock_irqrestore(&leak_lock, flags);
134#endif
135 atomic_set(&state->refs, 1);
136 init_waitqueue_head(&state->wq);
137 return state;
138}
139
140void free_extent_state(struct extent_state *state)
141{
142 if (!state)
143 return;
144 if (atomic_dec_and_test(&state->refs)) {
145#if LEAK_DEBUG
146 unsigned long flags;
147#endif
148 WARN_ON(state->tree);
149#if LEAK_DEBUG
150 spin_lock_irqsave(&leak_lock, flags);
151 list_del(&state->leak_list);
152 spin_unlock_irqrestore(&leak_lock, flags);
153#endif
154 kmem_cache_free(extent_state_cache, state);
155 }
156}
157
158static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
159 struct rb_node *node)
160{
161 struct rb_node **p = &root->rb_node;
162 struct rb_node *parent = NULL;
163 struct tree_entry *entry;
164
165 while (*p) {
166 parent = *p;
167 entry = rb_entry(parent, struct tree_entry, rb_node);
168
169 if (offset < entry->start)
170 p = &(*p)->rb_left;
171 else if (offset > entry->end)
172 p = &(*p)->rb_right;
173 else
174 return parent;
175 }
176
177 entry = rb_entry(node, struct tree_entry, rb_node);
178 rb_link_node(node, parent, p);
179 rb_insert_color(node, root);
180 return NULL;
181}
182
183static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
184 struct rb_node **prev_ret,
185 struct rb_node **next_ret)
186{
187 struct rb_root *root = &tree->state;
188 struct rb_node *n = root->rb_node;
189 struct rb_node *prev = NULL;
190 struct rb_node *orig_prev = NULL;
191 struct tree_entry *entry;
192 struct tree_entry *prev_entry = NULL;
193
194 while (n) {
195 entry = rb_entry(n, struct tree_entry, rb_node);
196 prev = n;
197 prev_entry = entry;
198
199 if (offset < entry->start)
200 n = n->rb_left;
201 else if (offset > entry->end)
202 n = n->rb_right;
203 else
204 return n;
205 }
206
207 if (prev_ret) {
208 orig_prev = prev;
209 while (prev && offset > prev_entry->end) {
210 prev = rb_next(prev);
211 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
212 }
213 *prev_ret = prev;
214 prev = orig_prev;
215 }
216
217 if (next_ret) {
218 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
219 while (prev && offset < prev_entry->start) {
220 prev = rb_prev(prev);
221 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
222 }
223 *next_ret = prev;
224 }
225 return NULL;
226}
227
228static inline struct rb_node *tree_search(struct extent_io_tree *tree,
229 u64 offset)
230{
231 struct rb_node *prev = NULL;
232 struct rb_node *ret;
233
234 ret = __etree_search(tree, offset, &prev, NULL);
235 if (!ret)
236 return prev;
237 return ret;
238}
239
240static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
241 struct extent_state *other)
242{
243 if (tree->ops && tree->ops->merge_extent_hook)
244 tree->ops->merge_extent_hook(tree->mapping->host, new,
245 other);
246}
247
248/*
249 * utility function to look for merge candidates inside a given range.
250 * Any extents with matching state are merged together into a single
251 * extent in the tree. Extents with EXTENT_IO in their state field
252 * are not merged because the end_io handlers need to be able to do
253 * operations on them without sleeping (or doing allocations/splits).
254 *
255 * This should be called with the tree lock held.
256 */
257static void merge_state(struct extent_io_tree *tree,
258 struct extent_state *state)
259{
260 struct extent_state *other;
261 struct rb_node *other_node;
262
263 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
264 return;
265
266 other_node = rb_prev(&state->rb_node);
267 if (other_node) {
268 other = rb_entry(other_node, struct extent_state, rb_node);
269 if (other->end == state->start - 1 &&
270 other->state == state->state) {
271 merge_cb(tree, state, other);
272 state->start = other->start;
273 other->tree = NULL;
274 rb_erase(&other->rb_node, &tree->state);
275 free_extent_state(other);
276 }
277 }
278 other_node = rb_next(&state->rb_node);
279 if (other_node) {
280 other = rb_entry(other_node, struct extent_state, rb_node);
281 if (other->start == state->end + 1 &&
282 other->state == state->state) {
283 merge_cb(tree, state, other);
284 state->end = other->end;
285 other->tree = NULL;
286 rb_erase(&other->rb_node, &tree->state);
287 free_extent_state(other);
288 }
289 }
290}
291
292static void set_state_cb(struct extent_io_tree *tree,
293 struct extent_state *state, int *bits)
294{
295 if (tree->ops && tree->ops->set_bit_hook)
296 tree->ops->set_bit_hook(tree->mapping->host, state, bits);
297}
298
299static void clear_state_cb(struct extent_io_tree *tree,
300 struct extent_state *state, int *bits)
301{
302 if (tree->ops && tree->ops->clear_bit_hook)
303 tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
304}
305
306static void set_state_bits(struct extent_io_tree *tree,
307 struct extent_state *state, int *bits);
308
309/*
310 * insert an extent_state struct into the tree. 'bits' are set on the
311 * struct before it is inserted.
312 *
313 * This may return -EEXIST if the extent is already there, in which case the
314 * state struct is freed.
315 *
316 * The tree lock is not taken internally. This is a utility function and
317 * probably isn't what you want to call (see set/clear_extent_bit).
318 */
319static int insert_state(struct extent_io_tree *tree,
320 struct extent_state *state, u64 start, u64 end,
321 int *bits)
322{
323 struct rb_node *node;
324
325 if (end < start) {
326 printk(KERN_ERR "btrfs end < start %llu %llu\n",
327 (unsigned long long)end,
328 (unsigned long long)start);
329 WARN_ON(1);
330 }
331 state->start = start;
332 state->end = end;
333
334 set_state_bits(tree, state, bits);
335
336 node = tree_insert(&tree->state, end, &state->rb_node);
337 if (node) {
338 struct extent_state *found;
339 found = rb_entry(node, struct extent_state, rb_node);
340 printk(KERN_ERR "btrfs found node %llu %llu on insert of "
341 "%llu %llu\n", (unsigned long long)found->start,
342 (unsigned long long)found->end,
343 (unsigned long long)start, (unsigned long long)end);
344 return -EEXIST;
345 }
346 state->tree = tree;
347 merge_state(tree, state);
348 return 0;
349}
350
351static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
352 u64 split)
353{
354 if (tree->ops && tree->ops->split_extent_hook)
355 tree->ops->split_extent_hook(tree->mapping->host, orig, split);
356}
357
358/*
359 * split a given extent state struct in two, inserting the preallocated
360 * struct 'prealloc' as the newly created second half. 'split' indicates an
361 * offset inside 'orig' where it should be split.
362 *
363 * Before calling,
364 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
365 * are two extent state structs in the tree:
366 * prealloc: [orig->start, split - 1]
367 * orig: [ split, orig->end ]
368 *
369 * The tree locks are not taken by this function. They need to be held
370 * by the caller.
371 */
372static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
373 struct extent_state *prealloc, u64 split)
374{
375 struct rb_node *node;
376
377 split_cb(tree, orig, split);
378
379 prealloc->start = orig->start;
380 prealloc->end = split - 1;
381 prealloc->state = orig->state;
382 orig->start = split;
383
384 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
385 if (node) {
386 free_extent_state(prealloc);
387 return -EEXIST;
388 }
389 prealloc->tree = tree;
390 return 0;
391}
392
393/*
394 * utility function to clear some bits in an extent state struct.
395 * it will optionally wake up any one waiting on this state (wake == 1), or
396 * forcibly remove the state from the tree (delete == 1).
397 *
398 * If no bits are set on the state struct after clearing things, the
399 * struct is freed and removed from the tree
400 */
401static int clear_state_bit(struct extent_io_tree *tree,
402 struct extent_state *state,
403 int *bits, int wake)
404{
405 int bits_to_clear = *bits & ~EXTENT_CTLBITS;
406 int ret = state->state & bits_to_clear;
407
408 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
409 u64 range = state->end - state->start + 1;
410 WARN_ON(range > tree->dirty_bytes);
411 tree->dirty_bytes -= range;
412 }
413 clear_state_cb(tree, state, bits);
414 state->state &= ~bits_to_clear;
415 if (wake)
416 wake_up(&state->wq);
417 if (state->state == 0) {
418 if (state->tree) {
419 rb_erase(&state->rb_node, &tree->state);
420 state->tree = NULL;
421 free_extent_state(state);
422 } else {
423 WARN_ON(1);
424 }
425 } else {
426 merge_state(tree, state);
427 }
428 return ret;
429}
430
431static struct extent_state *
432alloc_extent_state_atomic(struct extent_state *prealloc)
433{
434 if (!prealloc)
435 prealloc = alloc_extent_state(GFP_ATOMIC);
436
437 return prealloc;
438}
439
440/*
441 * clear some bits on a range in the tree. This may require splitting
442 * or inserting elements in the tree, so the gfp mask is used to
443 * indicate which allocations or sleeping are allowed.
444 *
445 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
446 * the given range from the tree regardless of state (ie for truncate).
447 *
448 * the range [start, end] is inclusive.
449 *
450 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
451 * bits were already set, or zero if none of the bits were already set.
452 */
453int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
454 int bits, int wake, int delete,
455 struct extent_state **cached_state,
456 gfp_t mask)
457{
458 struct extent_state *state;
459 struct extent_state *cached;
460 struct extent_state *prealloc = NULL;
461 struct rb_node *next_node;
462 struct rb_node *node;
463 u64 last_end;
464 int err;
465 int set = 0;
466 int clear = 0;
467
468 if (delete)
469 bits |= ~EXTENT_CTLBITS;
470 bits |= EXTENT_FIRST_DELALLOC;
471
472 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
473 clear = 1;
474again:
475 if (!prealloc && (mask & __GFP_WAIT)) {
476 prealloc = alloc_extent_state(mask);
477 if (!prealloc)
478 return -ENOMEM;
479 }
480
481 spin_lock(&tree->lock);
482 if (cached_state) {
483 cached = *cached_state;
484
485 if (clear) {
486 *cached_state = NULL;
487 cached_state = NULL;
488 }
489
490 if (cached && cached->tree && cached->start <= start &&
491 cached->end > start) {
492 if (clear)
493 atomic_dec(&cached->refs);
494 state = cached;
495 goto hit_next;
496 }
497 if (clear)
498 free_extent_state(cached);
499 }
500 /*
501 * this search will find the extents that end after
502 * our range starts
503 */
504 node = tree_search(tree, start);
505 if (!node)
506 goto out;
507 state = rb_entry(node, struct extent_state, rb_node);
508hit_next:
509 if (state->start > end)
510 goto out;
511 WARN_ON(state->end < start);
512 last_end = state->end;
513
514 /*
515 * | ---- desired range ---- |
516 * | state | or
517 * | ------------- state -------------- |
518 *
519 * We need to split the extent we found, and may flip
520 * bits on second half.
521 *
522 * If the extent we found extends past our range, we
523 * just split and search again. It'll get split again
524 * the next time though.
525 *
526 * If the extent we found is inside our range, we clear
527 * the desired bit on it.
528 */
529
530 if (state->start < start) {
531 prealloc = alloc_extent_state_atomic(prealloc);
532 BUG_ON(!prealloc);
533 err = split_state(tree, state, prealloc, start);
534 BUG_ON(err == -EEXIST);
535 prealloc = NULL;
536 if (err)
537 goto out;
538 if (state->end <= end) {
539 set |= clear_state_bit(tree, state, &bits, wake);
540 if (last_end == (u64)-1)
541 goto out;
542 start = last_end + 1;
543 }
544 goto search_again;
545 }
546 /*
547 * | ---- desired range ---- |
548 * | state |
549 * We need to split the extent, and clear the bit
550 * on the first half
551 */
552 if (state->start <= end && state->end > end) {
553 prealloc = alloc_extent_state_atomic(prealloc);
554 BUG_ON(!prealloc);
555 err = split_state(tree, state, prealloc, end + 1);
556 BUG_ON(err == -EEXIST);
557 if (wake)
558 wake_up(&state->wq);
559
560 set |= clear_state_bit(tree, prealloc, &bits, wake);
561
562 prealloc = NULL;
563 goto out;
564 }
565
566 if (state->end < end && prealloc && !need_resched())
567 next_node = rb_next(&state->rb_node);
568 else
569 next_node = NULL;
570
571 set |= clear_state_bit(tree, state, &bits, wake);
572 if (last_end == (u64)-1)
573 goto out;
574 start = last_end + 1;
575 if (start <= end && next_node) {
576 state = rb_entry(next_node, struct extent_state,
577 rb_node);
578 if (state->start == start)
579 goto hit_next;
580 }
581 goto search_again;
582
583out:
584 spin_unlock(&tree->lock);
585 if (prealloc)
586 free_extent_state(prealloc);
587
588 return set;
589
590search_again:
591 if (start > end)
592 goto out;
593 spin_unlock(&tree->lock);
594 if (mask & __GFP_WAIT)
595 cond_resched();
596 goto again;
597}
598
599static int wait_on_state(struct extent_io_tree *tree,
600 struct extent_state *state)
601 __releases(tree->lock)
602 __acquires(tree->lock)
603{
604 DEFINE_WAIT(wait);
605 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
606 spin_unlock(&tree->lock);
607 schedule();
608 spin_lock(&tree->lock);
609 finish_wait(&state->wq, &wait);
610 return 0;
611}
612
613/*
614 * waits for one or more bits to clear on a range in the state tree.
615 * The range [start, end] is inclusive.
616 * The tree lock is taken by this function
617 */
618int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
619{
620 struct extent_state *state;
621 struct rb_node *node;
622
623 spin_lock(&tree->lock);
624again:
625 while (1) {
626 /*
627 * this search will find all the extents that end after
628 * our range starts
629 */
630 node = tree_search(tree, start);
631 if (!node)
632 break;
633
634 state = rb_entry(node, struct extent_state, rb_node);
635
636 if (state->start > end)
637 goto out;
638
639 if (state->state & bits) {
640 start = state->start;
641 atomic_inc(&state->refs);
642 wait_on_state(tree, state);
643 free_extent_state(state);
644 goto again;
645 }
646 start = state->end + 1;
647
648 if (start > end)
649 break;
650
651 cond_resched_lock(&tree->lock);
652 }
653out:
654 spin_unlock(&tree->lock);
655 return 0;
656}
657
658static void set_state_bits(struct extent_io_tree *tree,
659 struct extent_state *state,
660 int *bits)
661{
662 int bits_to_set = *bits & ~EXTENT_CTLBITS;
663
664 set_state_cb(tree, state, bits);
665 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
666 u64 range = state->end - state->start + 1;
667 tree->dirty_bytes += range;
668 }
669 state->state |= bits_to_set;
670}
671
672static void cache_state(struct extent_state *state,
673 struct extent_state **cached_ptr)
674{
675 if (cached_ptr && !(*cached_ptr)) {
676 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
677 *cached_ptr = state;
678 atomic_inc(&state->refs);
679 }
680 }
681}
682
683static void uncache_state(struct extent_state **cached_ptr)
684{
685 if (cached_ptr && (*cached_ptr)) {
686 struct extent_state *state = *cached_ptr;
687 *cached_ptr = NULL;
688 free_extent_state(state);
689 }
690}
691
692/*
693 * set some bits on a range in the tree. This may require allocations or
694 * sleeping, so the gfp mask is used to indicate what is allowed.
695 *
696 * If any of the exclusive bits are set, this will fail with -EEXIST if some
697 * part of the range already has the desired bits set. The start of the
698 * existing range is returned in failed_start in this case.
699 *
700 * [start, end] is inclusive This takes the tree lock.
701 */
702
703int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
704 int bits, int exclusive_bits, u64 *failed_start,
705 struct extent_state **cached_state, gfp_t mask)
706{
707 struct extent_state *state;
708 struct extent_state *prealloc = NULL;
709 struct rb_node *node;
710 int err = 0;
711 u64 last_start;
712 u64 last_end;
713
714 bits |= EXTENT_FIRST_DELALLOC;
715again:
716 if (!prealloc && (mask & __GFP_WAIT)) {
717 prealloc = alloc_extent_state(mask);
718 BUG_ON(!prealloc);
719 }
720
721 spin_lock(&tree->lock);
722 if (cached_state && *cached_state) {
723 state = *cached_state;
724 if (state->start <= start && state->end > start &&
725 state->tree) {
726 node = &state->rb_node;
727 goto hit_next;
728 }
729 }
730 /*
731 * this search will find all the extents that end after
732 * our range starts.
733 */
734 node = tree_search(tree, start);
735 if (!node) {
736 prealloc = alloc_extent_state_atomic(prealloc);
737 BUG_ON(!prealloc);
738 err = insert_state(tree, prealloc, start, end, &bits);
739 prealloc = NULL;
740 BUG_ON(err == -EEXIST);
741 goto out;
742 }
743 state = rb_entry(node, struct extent_state, rb_node);
744hit_next:
745 last_start = state->start;
746 last_end = state->end;
747
748 /*
749 * | ---- desired range ---- |
750 * | state |
751 *
752 * Just lock what we found and keep going
753 */
754 if (state->start == start && state->end <= end) {
755 struct rb_node *next_node;
756 if (state->state & exclusive_bits) {
757 *failed_start = state->start;
758 err = -EEXIST;
759 goto out;
760 }
761
762 set_state_bits(tree, state, &bits);
763
764 cache_state(state, cached_state);
765 merge_state(tree, state);
766 if (last_end == (u64)-1)
767 goto out;
768
769 start = last_end + 1;
770 next_node = rb_next(&state->rb_node);
771 if (next_node && start < end && prealloc && !need_resched()) {
772 state = rb_entry(next_node, struct extent_state,
773 rb_node);
774 if (state->start == start)
775 goto hit_next;
776 }
777 goto search_again;
778 }
779
780 /*
781 * | ---- desired range ---- |
782 * | state |
783 * or
784 * | ------------- state -------------- |
785 *
786 * We need to split the extent we found, and may flip bits on
787 * second half.
788 *
789 * If the extent we found extends past our
790 * range, we just split and search again. It'll get split
791 * again the next time though.
792 *
793 * If the extent we found is inside our range, we set the
794 * desired bit on it.
795 */
796 if (state->start < start) {
797 if (state->state & exclusive_bits) {
798 *failed_start = start;
799 err = -EEXIST;
800 goto out;
801 }
802
803 prealloc = alloc_extent_state_atomic(prealloc);
804 BUG_ON(!prealloc);
805 err = split_state(tree, state, prealloc, start);
806 BUG_ON(err == -EEXIST);
807 prealloc = NULL;
808 if (err)
809 goto out;
810 if (state->end <= end) {
811 set_state_bits(tree, state, &bits);
812 cache_state(state, cached_state);
813 merge_state(tree, state);
814 if (last_end == (u64)-1)
815 goto out;
816 start = last_end + 1;
817 }
818 goto search_again;
819 }
820 /*
821 * | ---- desired range ---- |
822 * | state | or | state |
823 *
824 * There's a hole, we need to insert something in it and
825 * ignore the extent we found.
826 */
827 if (state->start > start) {
828 u64 this_end;
829 if (end < last_start)
830 this_end = end;
831 else
832 this_end = last_start - 1;
833
834 prealloc = alloc_extent_state_atomic(prealloc);
835 BUG_ON(!prealloc);
836
837 /*
838 * Avoid to free 'prealloc' if it can be merged with
839 * the later extent.
840 */
841 err = insert_state(tree, prealloc, start, this_end,
842 &bits);
843 BUG_ON(err == -EEXIST);
844 if (err) {
845 free_extent_state(prealloc);
846 prealloc = NULL;
847 goto out;
848 }
849 cache_state(prealloc, cached_state);
850 prealloc = NULL;
851 start = this_end + 1;
852 goto search_again;
853 }
854 /*
855 * | ---- desired range ---- |
856 * | state |
857 * We need to split the extent, and set the bit
858 * on the first half
859 */
860 if (state->start <= end && state->end > end) {
861 if (state->state & exclusive_bits) {
862 *failed_start = start;
863 err = -EEXIST;
864 goto out;
865 }
866
867 prealloc = alloc_extent_state_atomic(prealloc);
868 BUG_ON(!prealloc);
869 err = split_state(tree, state, prealloc, end + 1);
870 BUG_ON(err == -EEXIST);
871
872 set_state_bits(tree, prealloc, &bits);
873 cache_state(prealloc, cached_state);
874 merge_state(tree, prealloc);
875 prealloc = NULL;
876 goto out;
877 }
878
879 goto search_again;
880
881out:
882 spin_unlock(&tree->lock);
883 if (prealloc)
884 free_extent_state(prealloc);
885
886 return err;
887
888search_again:
889 if (start > end)
890 goto out;
891 spin_unlock(&tree->lock);
892 if (mask & __GFP_WAIT)
893 cond_resched();
894 goto again;
895}
896
897/* wrappers around set/clear extent bit */
898int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
899 gfp_t mask)
900{
901 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
902 NULL, mask);
903}
904
905int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
906 int bits, gfp_t mask)
907{
908 return set_extent_bit(tree, start, end, bits, 0, NULL,
909 NULL, mask);
910}
911
912int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
913 int bits, gfp_t mask)
914{
915 return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
916}
917
918int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
919 struct extent_state **cached_state, gfp_t mask)
920{
921 return set_extent_bit(tree, start, end,
922 EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
923 0, NULL, cached_state, mask);
924}
925
926int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
927 gfp_t mask)
928{
929 return clear_extent_bit(tree, start, end,
930 EXTENT_DIRTY | EXTENT_DELALLOC |
931 EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
932}
933
934int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
935 gfp_t mask)
936{
937 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
938 NULL, mask);
939}
940
941int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
942 struct extent_state **cached_state, gfp_t mask)
943{
944 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0,
945 NULL, cached_state, mask);
946}
947
948static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
949 u64 end, struct extent_state **cached_state,
950 gfp_t mask)
951{
952 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
953 cached_state, mask);
954}
955
956/*
957 * either insert or lock state struct between start and end use mask to tell
958 * us if waiting is desired.
959 */
960int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
961 int bits, struct extent_state **cached_state, gfp_t mask)
962{
963 int err;
964 u64 failed_start;
965 while (1) {
966 err = set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
967 EXTENT_LOCKED, &failed_start,
968 cached_state, mask);
969 if (err == -EEXIST && (mask & __GFP_WAIT)) {
970 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
971 start = failed_start;
972 } else {
973 break;
974 }
975 WARN_ON(start > end);
976 }
977 return err;
978}
979
980int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
981{
982 return lock_extent_bits(tree, start, end, 0, NULL, mask);
983}
984
985int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
986 gfp_t mask)
987{
988 int err;
989 u64 failed_start;
990
991 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
992 &failed_start, NULL, mask);
993 if (err == -EEXIST) {
994 if (failed_start > start)
995 clear_extent_bit(tree, start, failed_start - 1,
996 EXTENT_LOCKED, 1, 0, NULL, mask);
997 return 0;
998 }
999 return 1;
1000}
1001
1002int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
1003 struct extent_state **cached, gfp_t mask)
1004{
1005 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
1006 mask);
1007}
1008
1009int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
1010{
1011 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1012 mask);
1013}
1014
1015/*
1016 * helper function to set both pages and extents in the tree writeback
1017 */
1018static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1019{
1020 unsigned long index = start >> PAGE_CACHE_SHIFT;
1021 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1022 struct page *page;
1023
1024 while (index <= end_index) {
1025 page = find_get_page(tree->mapping, index);
1026 BUG_ON(!page);
1027 set_page_writeback(page);
1028 page_cache_release(page);
1029 index++;
1030 }
1031 return 0;
1032}
1033
1034/* find the first state struct with 'bits' set after 'start', and
1035 * return it. tree->lock must be held. NULL will returned if
1036 * nothing was found after 'start'
1037 */
1038struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
1039 u64 start, int bits)
1040{
1041 struct rb_node *node;
1042 struct extent_state *state;
1043
1044 /*
1045 * this search will find all the extents that end after
1046 * our range starts.
1047 */
1048 node = tree_search(tree, start);
1049 if (!node)
1050 goto out;
1051
1052 while (1) {
1053 state = rb_entry(node, struct extent_state, rb_node);
1054 if (state->end >= start && (state->state & bits))
1055 return state;
1056
1057 node = rb_next(node);
1058 if (!node)
1059 break;
1060 }
1061out:
1062 return NULL;
1063}
1064
1065/*
1066 * find the first offset in the io tree with 'bits' set. zero is
1067 * returned if we find something, and *start_ret and *end_ret are
1068 * set to reflect the state struct that was found.
1069 *
1070 * If nothing was found, 1 is returned, < 0 on error
1071 */
1072int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1073 u64 *start_ret, u64 *end_ret, int bits)
1074{
1075 struct extent_state *state;
1076 int ret = 1;
1077
1078 spin_lock(&tree->lock);
1079 state = find_first_extent_bit_state(tree, start, bits);
1080 if (state) {
1081 *start_ret = state->start;
1082 *end_ret = state->end;
1083 ret = 0;
1084 }
1085 spin_unlock(&tree->lock);
1086 return ret;
1087}
1088
1089/*
1090 * find a contiguous range of bytes in the file marked as delalloc, not
1091 * more than 'max_bytes'. start and end are used to return the range,
1092 *
1093 * 1 is returned if we find something, 0 if nothing was in the tree
1094 */
1095static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1096 u64 *start, u64 *end, u64 max_bytes,
1097 struct extent_state **cached_state)
1098{
1099 struct rb_node *node;
1100 struct extent_state *state;
1101 u64 cur_start = *start;
1102 u64 found = 0;
1103 u64 total_bytes = 0;
1104
1105 spin_lock(&tree->lock);
1106
1107 /*
1108 * this search will find all the extents that end after
1109 * our range starts.
1110 */
1111 node = tree_search(tree, cur_start);
1112 if (!node) {
1113 if (!found)
1114 *end = (u64)-1;
1115 goto out;
1116 }
1117
1118 while (1) {
1119 state = rb_entry(node, struct extent_state, rb_node);
1120 if (found && (state->start != cur_start ||
1121 (state->state & EXTENT_BOUNDARY))) {
1122 goto out;
1123 }
1124 if (!(state->state & EXTENT_DELALLOC)) {
1125 if (!found)
1126 *end = state->end;
1127 goto out;
1128 }
1129 if (!found) {
1130 *start = state->start;
1131 *cached_state = state;
1132 atomic_inc(&state->refs);
1133 }
1134 found++;
1135 *end = state->end;
1136 cur_start = state->end + 1;
1137 node = rb_next(node);
1138 if (!node)
1139 break;
1140 total_bytes += state->end - state->start + 1;
1141 if (total_bytes >= max_bytes)
1142 break;
1143 }
1144out:
1145 spin_unlock(&tree->lock);
1146 return found;
1147}
1148
1149static noinline int __unlock_for_delalloc(struct inode *inode,
1150 struct page *locked_page,
1151 u64 start, u64 end)
1152{
1153 int ret;
1154 struct page *pages[16];
1155 unsigned long index = start >> PAGE_CACHE_SHIFT;
1156 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1157 unsigned long nr_pages = end_index - index + 1;
1158 int i;
1159
1160 if (index == locked_page->index && end_index == index)
1161 return 0;
1162
1163 while (nr_pages > 0) {
1164 ret = find_get_pages_contig(inode->i_mapping, index,
1165 min_t(unsigned long, nr_pages,
1166 ARRAY_SIZE(pages)), pages);
1167 for (i = 0; i < ret; i++) {
1168 if (pages[i] != locked_page)
1169 unlock_page(pages[i]);
1170 page_cache_release(pages[i]);
1171 }
1172 nr_pages -= ret;
1173 index += ret;
1174 cond_resched();
1175 }
1176 return 0;
1177}
1178
1179static noinline int lock_delalloc_pages(struct inode *inode,
1180 struct page *locked_page,
1181 u64 delalloc_start,
1182 u64 delalloc_end)
1183{
1184 unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
1185 unsigned long start_index = index;
1186 unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
1187 unsigned long pages_locked = 0;
1188 struct page *pages[16];
1189 unsigned long nrpages;
1190 int ret;
1191 int i;
1192
1193 /* the caller is responsible for locking the start index */
1194 if (index == locked_page->index && index == end_index)
1195 return 0;
1196
1197 /* skip the page at the start index */
1198 nrpages = end_index - index + 1;
1199 while (nrpages > 0) {
1200 ret = find_get_pages_contig(inode->i_mapping, index,
1201 min_t(unsigned long,
1202 nrpages, ARRAY_SIZE(pages)), pages);
1203 if (ret == 0) {
1204 ret = -EAGAIN;
1205 goto done;
1206 }
1207 /* now we have an array of pages, lock them all */
1208 for (i = 0; i < ret; i++) {
1209 /*
1210 * the caller is taking responsibility for
1211 * locked_page
1212 */
1213 if (pages[i] != locked_page) {
1214 lock_page(pages[i]);
1215 if (!PageDirty(pages[i]) ||
1216 pages[i]->mapping != inode->i_mapping) {
1217 ret = -EAGAIN;
1218 unlock_page(pages[i]);
1219 page_cache_release(pages[i]);
1220 goto done;
1221 }
1222 }
1223 page_cache_release(pages[i]);
1224 pages_locked++;
1225 }
1226 nrpages -= ret;
1227 index += ret;
1228 cond_resched();
1229 }
1230 ret = 0;
1231done:
1232 if (ret && pages_locked) {
1233 __unlock_for_delalloc(inode, locked_page,
1234 delalloc_start,
1235 ((u64)(start_index + pages_locked - 1)) <<
1236 PAGE_CACHE_SHIFT);
1237 }
1238 return ret;
1239}
1240
1241/*
1242 * find a contiguous range of bytes in the file marked as delalloc, not
1243 * more than 'max_bytes'. start and end are used to return the range,
1244 *
1245 * 1 is returned if we find something, 0 if nothing was in the tree
1246 */
1247static noinline u64 find_lock_delalloc_range(struct inode *inode,
1248 struct extent_io_tree *tree,
1249 struct page *locked_page,
1250 u64 *start, u64 *end,
1251 u64 max_bytes)
1252{
1253 u64 delalloc_start;
1254 u64 delalloc_end;
1255 u64 found;
1256 struct extent_state *cached_state = NULL;
1257 int ret;
1258 int loops = 0;
1259
1260again:
1261 /* step one, find a bunch of delalloc bytes starting at start */
1262 delalloc_start = *start;
1263 delalloc_end = 0;
1264 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1265 max_bytes, &cached_state);
1266 if (!found || delalloc_end <= *start) {
1267 *start = delalloc_start;
1268 *end = delalloc_end;
1269 free_extent_state(cached_state);
1270 return found;
1271 }
1272
1273 /*
1274 * start comes from the offset of locked_page. We have to lock
1275 * pages in order, so we can't process delalloc bytes before
1276 * locked_page
1277 */
1278 if (delalloc_start < *start)
1279 delalloc_start = *start;
1280
1281 /*
1282 * make sure to limit the number of pages we try to lock down
1283 * if we're looping.
1284 */
1285 if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1286 delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
1287
1288 /* step two, lock all the pages after the page that has start */
1289 ret = lock_delalloc_pages(inode, locked_page,
1290 delalloc_start, delalloc_end);
1291 if (ret == -EAGAIN) {
1292 /* some of the pages are gone, lets avoid looping by
1293 * shortening the size of the delalloc range we're searching
1294 */
1295 free_extent_state(cached_state);
1296 if (!loops) {
1297 unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
1298 max_bytes = PAGE_CACHE_SIZE - offset;
1299 loops = 1;
1300 goto again;
1301 } else {
1302 found = 0;
1303 goto out_failed;
1304 }
1305 }
1306 BUG_ON(ret);
1307
1308 /* step three, lock the state bits for the whole range */
1309 lock_extent_bits(tree, delalloc_start, delalloc_end,
1310 0, &cached_state, GFP_NOFS);
1311
1312 /* then test to make sure it is all still delalloc */
1313 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1314 EXTENT_DELALLOC, 1, cached_state);
1315 if (!ret) {
1316 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1317 &cached_state, GFP_NOFS);
1318 __unlock_for_delalloc(inode, locked_page,
1319 delalloc_start, delalloc_end);
1320 cond_resched();
1321 goto again;
1322 }
1323 free_extent_state(cached_state);
1324 *start = delalloc_start;
1325 *end = delalloc_end;
1326out_failed:
1327 return found;
1328}
1329
1330int extent_clear_unlock_delalloc(struct inode *inode,
1331 struct extent_io_tree *tree,
1332 u64 start, u64 end, struct page *locked_page,
1333 unsigned long op)
1334{
1335 int ret;
1336 struct page *pages[16];
1337 unsigned long index = start >> PAGE_CACHE_SHIFT;
1338 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1339 unsigned long nr_pages = end_index - index + 1;
1340 int i;
1341 int clear_bits = 0;
1342
1343 if (op & EXTENT_CLEAR_UNLOCK)
1344 clear_bits |= EXTENT_LOCKED;
1345 if (op & EXTENT_CLEAR_DIRTY)
1346 clear_bits |= EXTENT_DIRTY;
1347
1348 if (op & EXTENT_CLEAR_DELALLOC)
1349 clear_bits |= EXTENT_DELALLOC;
1350
1351 clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1352 if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
1353 EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
1354 EXTENT_SET_PRIVATE2)))
1355 return 0;
1356
1357 while (nr_pages > 0) {
1358 ret = find_get_pages_contig(inode->i_mapping, index,
1359 min_t(unsigned long,
1360 nr_pages, ARRAY_SIZE(pages)), pages);
1361 for (i = 0; i < ret; i++) {
1362
1363 if (op & EXTENT_SET_PRIVATE2)
1364 SetPagePrivate2(pages[i]);
1365
1366 if (pages[i] == locked_page) {
1367 page_cache_release(pages[i]);
1368 continue;
1369 }
1370 if (op & EXTENT_CLEAR_DIRTY)
1371 clear_page_dirty_for_io(pages[i]);
1372 if (op & EXTENT_SET_WRITEBACK)
1373 set_page_writeback(pages[i]);
1374 if (op & EXTENT_END_WRITEBACK)
1375 end_page_writeback(pages[i]);
1376 if (op & EXTENT_CLEAR_UNLOCK_PAGE)
1377 unlock_page(pages[i]);
1378 page_cache_release(pages[i]);
1379 }
1380 nr_pages -= ret;
1381 index += ret;
1382 cond_resched();
1383 }
1384 return 0;
1385}
1386
1387/*
1388 * count the number of bytes in the tree that have a given bit(s)
1389 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1390 * cached. The total number found is returned.
1391 */
1392u64 count_range_bits(struct extent_io_tree *tree,
1393 u64 *start, u64 search_end, u64 max_bytes,
1394 unsigned long bits, int contig)
1395{
1396 struct rb_node *node;
1397 struct extent_state *state;
1398 u64 cur_start = *start;
1399 u64 total_bytes = 0;
1400 u64 last = 0;
1401 int found = 0;
1402
1403 if (search_end <= cur_start) {
1404 WARN_ON(1);
1405 return 0;
1406 }
1407
1408 spin_lock(&tree->lock);
1409 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1410 total_bytes = tree->dirty_bytes;
1411 goto out;
1412 }
1413 /*
1414 * this search will find all the extents that end after
1415 * our range starts.
1416 */
1417 node = tree_search(tree, cur_start);
1418 if (!node)
1419 goto out;
1420
1421 while (1) {
1422 state = rb_entry(node, struct extent_state, rb_node);
1423 if (state->start > search_end)
1424 break;
1425 if (contig && found && state->start > last + 1)
1426 break;
1427 if (state->end >= cur_start && (state->state & bits) == bits) {
1428 total_bytes += min(search_end, state->end) + 1 -
1429 max(cur_start, state->start);
1430 if (total_bytes >= max_bytes)
1431 break;
1432 if (!found) {
1433 *start = max(cur_start, state->start);
1434 found = 1;
1435 }
1436 last = state->end;
1437 } else if (contig && found) {
1438 break;
1439 }
1440 node = rb_next(node);
1441 if (!node)
1442 break;
1443 }
1444out:
1445 spin_unlock(&tree->lock);
1446 return total_bytes;
1447}
1448
1449/*
1450 * set the private field for a given byte offset in the tree. If there isn't
1451 * an extent_state there already, this does nothing.
1452 */
1453int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1454{
1455 struct rb_node *node;
1456 struct extent_state *state;
1457 int ret = 0;
1458
1459 spin_lock(&tree->lock);
1460 /*
1461 * this search will find all the extents that end after
1462 * our range starts.
1463 */
1464 node = tree_search(tree, start);
1465 if (!node) {
1466 ret = -ENOENT;
1467 goto out;
1468 }
1469 state = rb_entry(node, struct extent_state, rb_node);
1470 if (state->start != start) {
1471 ret = -ENOENT;
1472 goto out;
1473 }
1474 state->private = private;
1475out:
1476 spin_unlock(&tree->lock);
1477 return ret;
1478}
1479
1480int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1481{
1482 struct rb_node *node;
1483 struct extent_state *state;
1484 int ret = 0;
1485
1486 spin_lock(&tree->lock);
1487 /*
1488 * this search will find all the extents that end after
1489 * our range starts.
1490 */
1491 node = tree_search(tree, start);
1492 if (!node) {
1493 ret = -ENOENT;
1494 goto out;
1495 }
1496 state = rb_entry(node, struct extent_state, rb_node);
1497 if (state->start != start) {
1498 ret = -ENOENT;
1499 goto out;
1500 }
1501 *private = state->private;
1502out:
1503 spin_unlock(&tree->lock);
1504 return ret;
1505}
1506
1507/*
1508 * searches a range in the state tree for a given mask.
1509 * If 'filled' == 1, this returns 1 only if every extent in the tree
1510 * has the bits set. Otherwise, 1 is returned if any bit in the
1511 * range is found set.
1512 */
1513int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1514 int bits, int filled, struct extent_state *cached)
1515{
1516 struct extent_state *state = NULL;
1517 struct rb_node *node;
1518 int bitset = 0;
1519
1520 spin_lock(&tree->lock);
1521 if (cached && cached->tree && cached->start <= start &&
1522 cached->end > start)
1523 node = &cached->rb_node;
1524 else
1525 node = tree_search(tree, start);
1526 while (node && start <= end) {
1527 state = rb_entry(node, struct extent_state, rb_node);
1528
1529 if (filled && state->start > start) {
1530 bitset = 0;
1531 break;
1532 }
1533
1534 if (state->start > end)
1535 break;
1536
1537 if (state->state & bits) {
1538 bitset = 1;
1539 if (!filled)
1540 break;
1541 } else if (filled) {
1542 bitset = 0;
1543 break;
1544 }
1545
1546 if (state->end == (u64)-1)
1547 break;
1548
1549 start = state->end + 1;
1550 if (start > end)
1551 break;
1552 node = rb_next(node);
1553 if (!node) {
1554 if (filled)
1555 bitset = 0;
1556 break;
1557 }
1558 }
1559 spin_unlock(&tree->lock);
1560 return bitset;
1561}
1562
1563/*
1564 * helper function to set a given page up to date if all the
1565 * extents in the tree for that page are up to date
1566 */
1567static int check_page_uptodate(struct extent_io_tree *tree,
1568 struct page *page)
1569{
1570 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1571 u64 end = start + PAGE_CACHE_SIZE - 1;
1572 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1573 SetPageUptodate(page);
1574 return 0;
1575}
1576
1577/*
1578 * helper function to unlock a page if all the extents in the tree
1579 * for that page are unlocked
1580 */
1581static int check_page_locked(struct extent_io_tree *tree,
1582 struct page *page)
1583{
1584 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1585 u64 end = start + PAGE_CACHE_SIZE - 1;
1586 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
1587 unlock_page(page);
1588 return 0;
1589}
1590
1591/*
1592 * helper function to end page writeback if all the extents
1593 * in the tree for that page are done with writeback
1594 */
1595static int check_page_writeback(struct extent_io_tree *tree,
1596 struct page *page)
1597{
1598 end_page_writeback(page);
1599 return 0;
1600}
1601
1602/* lots and lots of room for performance fixes in the end_bio funcs */
1603
1604/*
1605 * after a writepage IO is done, we need to:
1606 * clear the uptodate bits on error
1607 * clear the writeback bits in the extent tree for this IO
1608 * end_page_writeback if the page has no more pending IO
1609 *
1610 * Scheduling is not allowed, so the extent state tree is expected
1611 * to have one and only one object corresponding to this IO.
1612 */
1613static void end_bio_extent_writepage(struct bio *bio, int err)
1614{
1615 int uptodate = err == 0;
1616 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1617 struct extent_io_tree *tree;
1618 u64 start;
1619 u64 end;
1620 int whole_page;
1621 int ret;
1622
1623 do {
1624 struct page *page = bvec->bv_page;
1625 tree = &BTRFS_I(page->mapping->host)->io_tree;
1626
1627 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1628 bvec->bv_offset;
1629 end = start + bvec->bv_len - 1;
1630
1631 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1632 whole_page = 1;
1633 else
1634 whole_page = 0;
1635
1636 if (--bvec >= bio->bi_io_vec)
1637 prefetchw(&bvec->bv_page->flags);
1638 if (tree->ops && tree->ops->writepage_end_io_hook) {
1639 ret = tree->ops->writepage_end_io_hook(page, start,
1640 end, NULL, uptodate);
1641 if (ret)
1642 uptodate = 0;
1643 }
1644
1645 if (!uptodate && tree->ops &&
1646 tree->ops->writepage_io_failed_hook) {
1647 ret = tree->ops->writepage_io_failed_hook(bio, page,
1648 start, end, NULL);
1649 if (ret == 0) {
1650 uptodate = (err == 0);
1651 continue;
1652 }
1653 }
1654
1655 if (!uptodate) {
1656 clear_extent_uptodate(tree, start, end, NULL, GFP_NOFS);
1657 ClearPageUptodate(page);
1658 SetPageError(page);
1659 }
1660
1661 if (whole_page)
1662 end_page_writeback(page);
1663 else
1664 check_page_writeback(tree, page);
1665 } while (bvec >= bio->bi_io_vec);
1666
1667 bio_put(bio);
1668}
1669
1670/*
1671 * after a readpage IO is done, we need to:
1672 * clear the uptodate bits on error
1673 * set the uptodate bits if things worked
1674 * set the page up to date if all extents in the tree are uptodate
1675 * clear the lock bit in the extent tree
1676 * unlock the page if there are no other extents locked for it
1677 *
1678 * Scheduling is not allowed, so the extent state tree is expected
1679 * to have one and only one object corresponding to this IO.
1680 */
1681static void end_bio_extent_readpage(struct bio *bio, int err)
1682{
1683 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1684 struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
1685 struct bio_vec *bvec = bio->bi_io_vec;
1686 struct extent_io_tree *tree;
1687 u64 start;
1688 u64 end;
1689 int whole_page;
1690 int ret;
1691
1692 if (err)
1693 uptodate = 0;
1694
1695 do {
1696 struct page *page = bvec->bv_page;
1697 struct extent_state *cached = NULL;
1698 struct extent_state *state;
1699
1700 tree = &BTRFS_I(page->mapping->host)->io_tree;
1701
1702 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1703 bvec->bv_offset;
1704 end = start + bvec->bv_len - 1;
1705
1706 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1707 whole_page = 1;
1708 else
1709 whole_page = 0;
1710
1711 if (++bvec <= bvec_end)
1712 prefetchw(&bvec->bv_page->flags);
1713
1714 spin_lock(&tree->lock);
1715 state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
1716 if (state && state->start == start) {
1717 /*
1718 * take a reference on the state, unlock will drop
1719 * the ref
1720 */
1721 cache_state(state, &cached);
1722 }
1723 spin_unlock(&tree->lock);
1724
1725 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1726 ret = tree->ops->readpage_end_io_hook(page, start, end,
1727 state);
1728 if (ret)
1729 uptodate = 0;
1730 }
1731 if (!uptodate && tree->ops &&
1732 tree->ops->readpage_io_failed_hook) {
1733 ret = tree->ops->readpage_io_failed_hook(bio, page,
1734 start, end, NULL);
1735 if (ret == 0) {
1736 uptodate =
1737 test_bit(BIO_UPTODATE, &bio->bi_flags);
1738 if (err)
1739 uptodate = 0;
1740 uncache_state(&cached);
1741 continue;
1742 }
1743 }
1744
1745 if (uptodate) {
1746 set_extent_uptodate(tree, start, end, &cached,
1747 GFP_ATOMIC);
1748 }
1749 unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
1750
1751 if (whole_page) {
1752 if (uptodate) {
1753 SetPageUptodate(page);
1754 } else {
1755 ClearPageUptodate(page);
1756 SetPageError(page);
1757 }
1758 unlock_page(page);
1759 } else {
1760 if (uptodate) {
1761 check_page_uptodate(tree, page);
1762 } else {
1763 ClearPageUptodate(page);
1764 SetPageError(page);
1765 }
1766 check_page_locked(tree, page);
1767 }
1768 } while (bvec <= bvec_end);
1769
1770 bio_put(bio);
1771}
1772
1773struct bio *
1774btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
1775 gfp_t gfp_flags)
1776{
1777 struct bio *bio;
1778
1779 bio = bio_alloc(gfp_flags, nr_vecs);
1780
1781 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
1782 while (!bio && (nr_vecs /= 2))
1783 bio = bio_alloc(gfp_flags, nr_vecs);
1784 }
1785
1786 if (bio) {
1787 bio->bi_size = 0;
1788 bio->bi_bdev = bdev;
1789 bio->bi_sector = first_sector;
1790 }
1791 return bio;
1792}
1793
1794static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
1795 unsigned long bio_flags)
1796{
1797 int ret = 0;
1798 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1799 struct page *page = bvec->bv_page;
1800 struct extent_io_tree *tree = bio->bi_private;
1801 u64 start;
1802
1803 start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1804
1805 bio->bi_private = NULL;
1806
1807 bio_get(bio);
1808
1809 if (tree->ops && tree->ops->submit_bio_hook)
1810 ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1811 mirror_num, bio_flags, start);
1812 else
1813 submit_bio(rw, bio);
1814 if (bio_flagged(bio, BIO_EOPNOTSUPP))
1815 ret = -EOPNOTSUPP;
1816 bio_put(bio);
1817 return ret;
1818}
1819
1820static int submit_extent_page(int rw, struct extent_io_tree *tree,
1821 struct page *page, sector_t sector,
1822 size_t size, unsigned long offset,
1823 struct block_device *bdev,
1824 struct bio **bio_ret,
1825 unsigned long max_pages,
1826 bio_end_io_t end_io_func,
1827 int mirror_num,
1828 unsigned long prev_bio_flags,
1829 unsigned long bio_flags)
1830{
1831 int ret = 0;
1832 struct bio *bio;
1833 int nr;
1834 int contig = 0;
1835 int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
1836 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
1837 size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
1838
1839 if (bio_ret && *bio_ret) {
1840 bio = *bio_ret;
1841 if (old_compressed)
1842 contig = bio->bi_sector == sector;
1843 else
1844 contig = bio->bi_sector + (bio->bi_size >> 9) ==
1845 sector;
1846
1847 if (prev_bio_flags != bio_flags || !contig ||
1848 (tree->ops && tree->ops->merge_bio_hook &&
1849 tree->ops->merge_bio_hook(page, offset, page_size, bio,
1850 bio_flags)) ||
1851 bio_add_page(bio, page, page_size, offset) < page_size) {
1852 ret = submit_one_bio(rw, bio, mirror_num,
1853 prev_bio_flags);
1854 bio = NULL;
1855 } else {
1856 return 0;
1857 }
1858 }
1859 if (this_compressed)
1860 nr = BIO_MAX_PAGES;
1861 else
1862 nr = bio_get_nr_vecs(bdev);
1863
1864 bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1865 if (!bio)
1866 return -ENOMEM;
1867
1868 bio_add_page(bio, page, page_size, offset);
1869 bio->bi_end_io = end_io_func;
1870 bio->bi_private = tree;
1871
1872 if (bio_ret)
1873 *bio_ret = bio;
1874 else
1875 ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
1876
1877 return ret;
1878}
1879
1880void set_page_extent_mapped(struct page *page)
1881{
1882 if (!PagePrivate(page)) {
1883 SetPagePrivate(page);
1884 page_cache_get(page);
1885 set_page_private(page, EXTENT_PAGE_PRIVATE);
1886 }
1887}
1888
1889static void set_page_extent_head(struct page *page, unsigned long len)
1890{
1891 WARN_ON(!PagePrivate(page));
1892 set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
1893}
1894
1895/*
1896 * basic readpage implementation. Locked extent state structs are inserted
1897 * into the tree that are removed when the IO is done (by the end_io
1898 * handlers)
1899 */
1900static int __extent_read_full_page(struct extent_io_tree *tree,
1901 struct page *page,
1902 get_extent_t *get_extent,
1903 struct bio **bio, int mirror_num,
1904 unsigned long *bio_flags)
1905{
1906 struct inode *inode = page->mapping->host;
1907 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1908 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1909 u64 end;
1910 u64 cur = start;
1911 u64 extent_offset;
1912 u64 last_byte = i_size_read(inode);
1913 u64 block_start;
1914 u64 cur_end;
1915 sector_t sector;
1916 struct extent_map *em;
1917 struct block_device *bdev;
1918 struct btrfs_ordered_extent *ordered;
1919 int ret;
1920 int nr = 0;
1921 size_t pg_offset = 0;
1922 size_t iosize;
1923 size_t disk_io_size;
1924 size_t blocksize = inode->i_sb->s_blocksize;
1925 unsigned long this_bio_flag = 0;
1926
1927 set_page_extent_mapped(page);
1928
1929 if (!PageUptodate(page)) {
1930 if (cleancache_get_page(page) == 0) {
1931 BUG_ON(blocksize != PAGE_SIZE);
1932 goto out;
1933 }
1934 }
1935
1936 end = page_end;
1937 while (1) {
1938 lock_extent(tree, start, end, GFP_NOFS);
1939 ordered = btrfs_lookup_ordered_extent(inode, start);
1940 if (!ordered)
1941 break;
1942 unlock_extent(tree, start, end, GFP_NOFS);
1943 btrfs_start_ordered_extent(inode, ordered, 1);
1944 btrfs_put_ordered_extent(ordered);
1945 }
1946
1947 if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
1948 char *userpage;
1949 size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
1950
1951 if (zero_offset) {
1952 iosize = PAGE_CACHE_SIZE - zero_offset;
1953 userpage = kmap_atomic(page, KM_USER0);
1954 memset(userpage + zero_offset, 0, iosize);
1955 flush_dcache_page(page);
1956 kunmap_atomic(userpage, KM_USER0);
1957 }
1958 }
1959 while (cur <= end) {
1960 if (cur >= last_byte) {
1961 char *userpage;
1962 struct extent_state *cached = NULL;
1963
1964 iosize = PAGE_CACHE_SIZE - pg_offset;
1965 userpage = kmap_atomic(page, KM_USER0);
1966 memset(userpage + pg_offset, 0, iosize);
1967 flush_dcache_page(page);
1968 kunmap_atomic(userpage, KM_USER0);
1969 set_extent_uptodate(tree, cur, cur + iosize - 1,
1970 &cached, GFP_NOFS);
1971 unlock_extent_cached(tree, cur, cur + iosize - 1,
1972 &cached, GFP_NOFS);
1973 break;
1974 }
1975 em = get_extent(inode, page, pg_offset, cur,
1976 end - cur + 1, 0);
1977 if (IS_ERR_OR_NULL(em)) {
1978 SetPageError(page);
1979 unlock_extent(tree, cur, end, GFP_NOFS);
1980 break;
1981 }
1982 extent_offset = cur - em->start;
1983 BUG_ON(extent_map_end(em) <= cur);
1984 BUG_ON(end < cur);
1985
1986 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1987 this_bio_flag = EXTENT_BIO_COMPRESSED;
1988 extent_set_compress_type(&this_bio_flag,
1989 em->compress_type);
1990 }
1991
1992 iosize = min(extent_map_end(em) - cur, end - cur + 1);
1993 cur_end = min(extent_map_end(em) - 1, end);
1994 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
1995 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
1996 disk_io_size = em->block_len;
1997 sector = em->block_start >> 9;
1998 } else {
1999 sector = (em->block_start + extent_offset) >> 9;
2000 disk_io_size = iosize;
2001 }
2002 bdev = em->bdev;
2003 block_start = em->block_start;
2004 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2005 block_start = EXTENT_MAP_HOLE;
2006 free_extent_map(em);
2007 em = NULL;
2008
2009 /* we've found a hole, just zero and go on */
2010 if (block_start == EXTENT_MAP_HOLE) {
2011 char *userpage;
2012 struct extent_state *cached = NULL;
2013
2014 userpage = kmap_atomic(page, KM_USER0);
2015 memset(userpage + pg_offset, 0, iosize);
2016 flush_dcache_page(page);
2017 kunmap_atomic(userpage, KM_USER0);
2018
2019 set_extent_uptodate(tree, cur, cur + iosize - 1,
2020 &cached, GFP_NOFS);
2021 unlock_extent_cached(tree, cur, cur + iosize - 1,
2022 &cached, GFP_NOFS);
2023 cur = cur + iosize;
2024 pg_offset += iosize;
2025 continue;
2026 }
2027 /* the get_extent function already copied into the page */
2028 if (test_range_bit(tree, cur, cur_end,
2029 EXTENT_UPTODATE, 1, NULL)) {
2030 check_page_uptodate(tree, page);
2031 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2032 cur = cur + iosize;
2033 pg_offset += iosize;
2034 continue;
2035 }
2036 /* we have an inline extent but it didn't get marked up
2037 * to date. Error out
2038 */
2039 if (block_start == EXTENT_MAP_INLINE) {
2040 SetPageError(page);
2041 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2042 cur = cur + iosize;
2043 pg_offset += iosize;
2044 continue;
2045 }
2046
2047 ret = 0;
2048 if (tree->ops && tree->ops->readpage_io_hook) {
2049 ret = tree->ops->readpage_io_hook(page, cur,
2050 cur + iosize - 1);
2051 }
2052 if (!ret) {
2053 unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
2054 pnr -= page->index;
2055 ret = submit_extent_page(READ, tree, page,
2056 sector, disk_io_size, pg_offset,
2057 bdev, bio, pnr,
2058 end_bio_extent_readpage, mirror_num,
2059 *bio_flags,
2060 this_bio_flag);
2061 nr++;
2062 *bio_flags = this_bio_flag;
2063 }
2064 if (ret)
2065 SetPageError(page);
2066 cur = cur + iosize;
2067 pg_offset += iosize;
2068 }
2069out:
2070 if (!nr) {
2071 if (!PageError(page))
2072 SetPageUptodate(page);
2073 unlock_page(page);
2074 }
2075 return 0;
2076}
2077
2078int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
2079 get_extent_t *get_extent)
2080{
2081 struct bio *bio = NULL;
2082 unsigned long bio_flags = 0;
2083 int ret;
2084
2085 ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
2086 &bio_flags);
2087 if (bio)
2088 ret = submit_one_bio(READ, bio, 0, bio_flags);
2089 return ret;
2090}
2091
2092static noinline void update_nr_written(struct page *page,
2093 struct writeback_control *wbc,
2094 unsigned long nr_written)
2095{
2096 wbc->nr_to_write -= nr_written;
2097 if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
2098 wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
2099 page->mapping->writeback_index = page->index + nr_written;
2100}
2101
2102/*
2103 * the writepage semantics are similar to regular writepage. extent
2104 * records are inserted to lock ranges in the tree, and as dirty areas
2105 * are found, they are marked writeback. Then the lock bits are removed
2106 * and the end_io handler clears the writeback ranges
2107 */
2108static int __extent_writepage(struct page *page, struct writeback_control *wbc,
2109 void *data)
2110{
2111 struct inode *inode = page->mapping->host;
2112 struct extent_page_data *epd = data;
2113 struct extent_io_tree *tree = epd->tree;
2114 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2115 u64 delalloc_start;
2116 u64 page_end = start + PAGE_CACHE_SIZE - 1;
2117 u64 end;
2118 u64 cur = start;
2119 u64 extent_offset;
2120 u64 last_byte = i_size_read(inode);
2121 u64 block_start;
2122 u64 iosize;
2123 sector_t sector;
2124 struct extent_state *cached_state = NULL;
2125 struct extent_map *em;
2126 struct block_device *bdev;
2127 int ret;
2128 int nr = 0;
2129 size_t pg_offset = 0;
2130 size_t blocksize;
2131 loff_t i_size = i_size_read(inode);
2132 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2133 u64 nr_delalloc;
2134 u64 delalloc_end;
2135 int page_started;
2136 int compressed;
2137 int write_flags;
2138 unsigned long nr_written = 0;
2139
2140 if (wbc->sync_mode == WB_SYNC_ALL)
2141 write_flags = WRITE_SYNC;
2142 else
2143 write_flags = WRITE;
2144
2145 trace___extent_writepage(page, inode, wbc);
2146
2147 WARN_ON(!PageLocked(page));
2148 pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2149 if (page->index > end_index ||
2150 (page->index == end_index && !pg_offset)) {
2151 page->mapping->a_ops->invalidatepage(page, 0);
2152 unlock_page(page);
2153 return 0;
2154 }
2155
2156 if (page->index == end_index) {
2157 char *userpage;
2158
2159 userpage = kmap_atomic(page, KM_USER0);
2160 memset(userpage + pg_offset, 0,
2161 PAGE_CACHE_SIZE - pg_offset);
2162 kunmap_atomic(userpage, KM_USER0);
2163 flush_dcache_page(page);
2164 }
2165 pg_offset = 0;
2166
2167 set_page_extent_mapped(page);
2168
2169 delalloc_start = start;
2170 delalloc_end = 0;
2171 page_started = 0;
2172 if (!epd->extent_locked) {
2173 u64 delalloc_to_write = 0;
2174 /*
2175 * make sure the wbc mapping index is at least updated
2176 * to this page.
2177 */
2178 update_nr_written(page, wbc, 0);
2179
2180 while (delalloc_end < page_end) {
2181 nr_delalloc = find_lock_delalloc_range(inode, tree,
2182 page,
2183 &delalloc_start,
2184 &delalloc_end,
2185 128 * 1024 * 1024);
2186 if (nr_delalloc == 0) {
2187 delalloc_start = delalloc_end + 1;
2188 continue;
2189 }
2190 tree->ops->fill_delalloc(inode, page, delalloc_start,
2191 delalloc_end, &page_started,
2192 &nr_written);
2193 /*
2194 * delalloc_end is already one less than the total
2195 * length, so we don't subtract one from
2196 * PAGE_CACHE_SIZE
2197 */
2198 delalloc_to_write += (delalloc_end - delalloc_start +
2199 PAGE_CACHE_SIZE) >>
2200 PAGE_CACHE_SHIFT;
2201 delalloc_start = delalloc_end + 1;
2202 }
2203 if (wbc->nr_to_write < delalloc_to_write) {
2204 int thresh = 8192;
2205
2206 if (delalloc_to_write < thresh * 2)
2207 thresh = delalloc_to_write;
2208 wbc->nr_to_write = min_t(u64, delalloc_to_write,
2209 thresh);
2210 }
2211
2212 /* did the fill delalloc function already unlock and start
2213 * the IO?
2214 */
2215 if (page_started) {
2216 ret = 0;
2217 /*
2218 * we've unlocked the page, so we can't update
2219 * the mapping's writeback index, just update
2220 * nr_to_write.
2221 */
2222 wbc->nr_to_write -= nr_written;
2223 goto done_unlocked;
2224 }
2225 }
2226 if (tree->ops && tree->ops->writepage_start_hook) {
2227 ret = tree->ops->writepage_start_hook(page, start,
2228 page_end);
2229 if (ret == -EAGAIN) {
2230 redirty_page_for_writepage(wbc, page);
2231 update_nr_written(page, wbc, nr_written);
2232 unlock_page(page);
2233 ret = 0;
2234 goto done_unlocked;
2235 }
2236 }
2237
2238 /*
2239 * we don't want to touch the inode after unlocking the page,
2240 * so we update the mapping writeback index now
2241 */
2242 update_nr_written(page, wbc, nr_written + 1);
2243
2244 end = page_end;
2245 if (last_byte <= start) {
2246 if (tree->ops && tree->ops->writepage_end_io_hook)
2247 tree->ops->writepage_end_io_hook(page, start,
2248 page_end, NULL, 1);
2249 goto done;
2250 }
2251
2252 blocksize = inode->i_sb->s_blocksize;
2253
2254 while (cur <= end) {
2255 if (cur >= last_byte) {
2256 if (tree->ops && tree->ops->writepage_end_io_hook)
2257 tree->ops->writepage_end_io_hook(page, cur,
2258 page_end, NULL, 1);
2259 break;
2260 }
2261 em = epd->get_extent(inode, page, pg_offset, cur,
2262 end - cur + 1, 1);
2263 if (IS_ERR_OR_NULL(em)) {
2264 SetPageError(page);
2265 break;
2266 }
2267
2268 extent_offset = cur - em->start;
2269 BUG_ON(extent_map_end(em) <= cur);
2270 BUG_ON(end < cur);
2271 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2272 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2273 sector = (em->block_start + extent_offset) >> 9;
2274 bdev = em->bdev;
2275 block_start = em->block_start;
2276 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2277 free_extent_map(em);
2278 em = NULL;
2279
2280 /*
2281 * compressed and inline extents are written through other
2282 * paths in the FS
2283 */
2284 if (compressed || block_start == EXTENT_MAP_HOLE ||
2285 block_start == EXTENT_MAP_INLINE) {
2286 /*
2287 * end_io notification does not happen here for
2288 * compressed extents
2289 */
2290 if (!compressed && tree->ops &&
2291 tree->ops->writepage_end_io_hook)
2292 tree->ops->writepage_end_io_hook(page, cur,
2293 cur + iosize - 1,
2294 NULL, 1);
2295 else if (compressed) {
2296 /* we don't want to end_page_writeback on
2297 * a compressed extent. this happens
2298 * elsewhere
2299 */
2300 nr++;
2301 }
2302
2303 cur += iosize;
2304 pg_offset += iosize;
2305 continue;
2306 }
2307 /* leave this out until we have a page_mkwrite call */
2308 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2309 EXTENT_DIRTY, 0, NULL)) {
2310 cur = cur + iosize;
2311 pg_offset += iosize;
2312 continue;
2313 }
2314
2315 if (tree->ops && tree->ops->writepage_io_hook) {
2316 ret = tree->ops->writepage_io_hook(page, cur,
2317 cur + iosize - 1);
2318 } else {
2319 ret = 0;
2320 }
2321 if (ret) {
2322 SetPageError(page);
2323 } else {
2324 unsigned long max_nr = end_index + 1;
2325
2326 set_range_writeback(tree, cur, cur + iosize - 1);
2327 if (!PageWriteback(page)) {
2328 printk(KERN_ERR "btrfs warning page %lu not "
2329 "writeback, cur %llu end %llu\n",
2330 page->index, (unsigned long long)cur,
2331 (unsigned long long)end);
2332 }
2333
2334 ret = submit_extent_page(write_flags, tree, page,
2335 sector, iosize, pg_offset,
2336 bdev, &epd->bio, max_nr,
2337 end_bio_extent_writepage,
2338 0, 0, 0);
2339 if (ret)
2340 SetPageError(page);
2341 }
2342 cur = cur + iosize;
2343 pg_offset += iosize;
2344 nr++;
2345 }
2346done:
2347 if (nr == 0) {
2348 /* make sure the mapping tag for page dirty gets cleared */
2349 set_page_writeback(page);
2350 end_page_writeback(page);
2351 }
2352 unlock_page(page);
2353
2354done_unlocked:
2355
2356 /* drop our reference on any cached states */
2357 free_extent_state(cached_state);
2358 return 0;
2359}
2360
2361/**
2362 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
2363 * @mapping: address space structure to write
2364 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
2365 * @writepage: function called for each page
2366 * @data: data passed to writepage function
2367 *
2368 * If a page is already under I/O, write_cache_pages() skips it, even
2369 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
2370 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
2371 * and msync() need to guarantee that all the data which was dirty at the time
2372 * the call was made get new I/O started against them. If wbc->sync_mode is
2373 * WB_SYNC_ALL then we were called for data integrity and we must wait for
2374 * existing IO to complete.
2375 */
2376static int extent_write_cache_pages(struct extent_io_tree *tree,
2377 struct address_space *mapping,
2378 struct writeback_control *wbc,
2379 writepage_t writepage, void *data,
2380 void (*flush_fn)(void *))
2381{
2382 int ret = 0;
2383 int done = 0;
2384 int nr_to_write_done = 0;
2385 struct pagevec pvec;
2386 int nr_pages;
2387 pgoff_t index;
2388 pgoff_t end; /* Inclusive */
2389 int scanned = 0;
2390 int tag;
2391
2392 pagevec_init(&pvec, 0);
2393 if (wbc->range_cyclic) {
2394 index = mapping->writeback_index; /* Start from prev offset */
2395 end = -1;
2396 } else {
2397 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2398 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2399 scanned = 1;
2400 }
2401 if (wbc->sync_mode == WB_SYNC_ALL)
2402 tag = PAGECACHE_TAG_TOWRITE;
2403 else
2404 tag = PAGECACHE_TAG_DIRTY;
2405retry:
2406 if (wbc->sync_mode == WB_SYNC_ALL)
2407 tag_pages_for_writeback(mapping, index, end);
2408 while (!done && !nr_to_write_done && (index <= end) &&
2409 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2410 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2411 unsigned i;
2412
2413 scanned = 1;
2414 for (i = 0; i < nr_pages; i++) {
2415 struct page *page = pvec.pages[i];
2416
2417 /*
2418 * At this point we hold neither mapping->tree_lock nor
2419 * lock on the page itself: the page may be truncated or
2420 * invalidated (changing page->mapping to NULL), or even
2421 * swizzled back from swapper_space to tmpfs file
2422 * mapping
2423 */
2424 if (tree->ops && tree->ops->write_cache_pages_lock_hook)
2425 tree->ops->write_cache_pages_lock_hook(page);
2426 else
2427 lock_page(page);
2428
2429 if (unlikely(page->mapping != mapping)) {
2430 unlock_page(page);
2431 continue;
2432 }
2433
2434 if (!wbc->range_cyclic && page->index > end) {
2435 done = 1;
2436 unlock_page(page);
2437 continue;
2438 }
2439
2440 if (wbc->sync_mode != WB_SYNC_NONE) {
2441 if (PageWriteback(page))
2442 flush_fn(data);
2443 wait_on_page_writeback(page);
2444 }
2445
2446 if (PageWriteback(page) ||
2447 !clear_page_dirty_for_io(page)) {
2448 unlock_page(page);
2449 continue;
2450 }
2451
2452 ret = (*writepage)(page, wbc, data);
2453
2454 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
2455 unlock_page(page);
2456 ret = 0;
2457 }
2458 if (ret)
2459 done = 1;
2460
2461 /*
2462 * the filesystem may choose to bump up nr_to_write.
2463 * We have to make sure to honor the new nr_to_write
2464 * at any time
2465 */
2466 nr_to_write_done = wbc->nr_to_write <= 0;
2467 }
2468 pagevec_release(&pvec);
2469 cond_resched();
2470 }
2471 if (!scanned && !done) {
2472 /*
2473 * We hit the last page and there is more work to be done: wrap
2474 * back to the start of the file
2475 */
2476 scanned = 1;
2477 index = 0;
2478 goto retry;
2479 }
2480 return ret;
2481}
2482
2483static void flush_epd_write_bio(struct extent_page_data *epd)
2484{
2485 if (epd->bio) {
2486 if (epd->sync_io)
2487 submit_one_bio(WRITE_SYNC, epd->bio, 0, 0);
2488 else
2489 submit_one_bio(WRITE, epd->bio, 0, 0);
2490 epd->bio = NULL;
2491 }
2492}
2493
2494static noinline void flush_write_bio(void *data)
2495{
2496 struct extent_page_data *epd = data;
2497 flush_epd_write_bio(epd);
2498}
2499
2500int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
2501 get_extent_t *get_extent,
2502 struct writeback_control *wbc)
2503{
2504 int ret;
2505 struct extent_page_data epd = {
2506 .bio = NULL,
2507 .tree = tree,
2508 .get_extent = get_extent,
2509 .extent_locked = 0,
2510 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2511 };
2512
2513 ret = __extent_writepage(page, wbc, &epd);
2514
2515 flush_epd_write_bio(&epd);
2516 return ret;
2517}
2518
2519int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
2520 u64 start, u64 end, get_extent_t *get_extent,
2521 int mode)
2522{
2523 int ret = 0;
2524 struct address_space *mapping = inode->i_mapping;
2525 struct page *page;
2526 unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
2527 PAGE_CACHE_SHIFT;
2528
2529 struct extent_page_data epd = {
2530 .bio = NULL,
2531 .tree = tree,
2532 .get_extent = get_extent,
2533 .extent_locked = 1,
2534 .sync_io = mode == WB_SYNC_ALL,
2535 };
2536 struct writeback_control wbc_writepages = {
2537 .sync_mode = mode,
2538 .nr_to_write = nr_pages * 2,
2539 .range_start = start,
2540 .range_end = end + 1,
2541 };
2542
2543 while (start <= end) {
2544 page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
2545 if (clear_page_dirty_for_io(page))
2546 ret = __extent_writepage(page, &wbc_writepages, &epd);
2547 else {
2548 if (tree->ops && tree->ops->writepage_end_io_hook)
2549 tree->ops->writepage_end_io_hook(page, start,
2550 start + PAGE_CACHE_SIZE - 1,
2551 NULL, 1);
2552 unlock_page(page);
2553 }
2554 page_cache_release(page);
2555 start += PAGE_CACHE_SIZE;
2556 }
2557
2558 flush_epd_write_bio(&epd);
2559 return ret;
2560}
2561
2562int extent_writepages(struct extent_io_tree *tree,
2563 struct address_space *mapping,
2564 get_extent_t *get_extent,
2565 struct writeback_control *wbc)
2566{
2567 int ret = 0;
2568 struct extent_page_data epd = {
2569 .bio = NULL,
2570 .tree = tree,
2571 .get_extent = get_extent,
2572 .extent_locked = 0,
2573 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2574 };
2575
2576 ret = extent_write_cache_pages(tree, mapping, wbc,
2577 __extent_writepage, &epd,
2578 flush_write_bio);
2579 flush_epd_write_bio(&epd);
2580 return ret;
2581}
2582
2583int extent_readpages(struct extent_io_tree *tree,
2584 struct address_space *mapping,
2585 struct list_head *pages, unsigned nr_pages,
2586 get_extent_t get_extent)
2587{
2588 struct bio *bio = NULL;
2589 unsigned page_idx;
2590 unsigned long bio_flags = 0;
2591
2592 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
2593 struct page *page = list_entry(pages->prev, struct page, lru);
2594
2595 prefetchw(&page->flags);
2596 list_del(&page->lru);
2597 if (!add_to_page_cache_lru(page, mapping,
2598 page->index, GFP_NOFS)) {
2599 __extent_read_full_page(tree, page, get_extent,
2600 &bio, 0, &bio_flags);
2601 }
2602 page_cache_release(page);
2603 }
2604 BUG_ON(!list_empty(pages));
2605 if (bio)
2606 submit_one_bio(READ, bio, 0, bio_flags);
2607 return 0;
2608}
2609
2610/*
2611 * basic invalidatepage code, this waits on any locked or writeback
2612 * ranges corresponding to the page, and then deletes any extent state
2613 * records from the tree
2614 */
2615int extent_invalidatepage(struct extent_io_tree *tree,
2616 struct page *page, unsigned long offset)
2617{
2618 struct extent_state *cached_state = NULL;
2619 u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
2620 u64 end = start + PAGE_CACHE_SIZE - 1;
2621 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
2622
2623 start += (offset + blocksize - 1) & ~(blocksize - 1);
2624 if (start > end)
2625 return 0;
2626
2627 lock_extent_bits(tree, start, end, 0, &cached_state, GFP_NOFS);
2628 wait_on_page_writeback(page);
2629 clear_extent_bit(tree, start, end,
2630 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
2631 EXTENT_DO_ACCOUNTING,
2632 1, 1, &cached_state, GFP_NOFS);
2633 return 0;
2634}
2635
2636/*
2637 * a helper for releasepage, this tests for areas of the page that
2638 * are locked or under IO and drops the related state bits if it is safe
2639 * to drop the page.
2640 */
2641int try_release_extent_state(struct extent_map_tree *map,
2642 struct extent_io_tree *tree, struct page *page,
2643 gfp_t mask)
2644{
2645 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2646 u64 end = start + PAGE_CACHE_SIZE - 1;
2647 int ret = 1;
2648
2649 if (test_range_bit(tree, start, end,
2650 EXTENT_IOBITS, 0, NULL))
2651 ret = 0;
2652 else {
2653 if ((mask & GFP_NOFS) == GFP_NOFS)
2654 mask = GFP_NOFS;
2655 /*
2656 * at this point we can safely clear everything except the
2657 * locked bit and the nodatasum bit
2658 */
2659 ret = clear_extent_bit(tree, start, end,
2660 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
2661 0, 0, NULL, mask);
2662
2663 /* if clear_extent_bit failed for enomem reasons,
2664 * we can't allow the release to continue.
2665 */
2666 if (ret < 0)
2667 ret = 0;
2668 else
2669 ret = 1;
2670 }
2671 return ret;
2672}
2673
2674/*
2675 * a helper for releasepage. As long as there are no locked extents
2676 * in the range corresponding to the page, both state records and extent
2677 * map records are removed
2678 */
2679int try_release_extent_mapping(struct extent_map_tree *map,
2680 struct extent_io_tree *tree, struct page *page,
2681 gfp_t mask)
2682{
2683 struct extent_map *em;
2684 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2685 u64 end = start + PAGE_CACHE_SIZE - 1;
2686
2687 if ((mask & __GFP_WAIT) &&
2688 page->mapping->host->i_size > 16 * 1024 * 1024) {
2689 u64 len;
2690 while (start <= end) {
2691 len = end - start + 1;
2692 write_lock(&map->lock);
2693 em = lookup_extent_mapping(map, start, len);
2694 if (IS_ERR_OR_NULL(em)) {
2695 write_unlock(&map->lock);
2696 break;
2697 }
2698 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
2699 em->start != start) {
2700 write_unlock(&map->lock);
2701 free_extent_map(em);
2702 break;
2703 }
2704 if (!test_range_bit(tree, em->start,
2705 extent_map_end(em) - 1,
2706 EXTENT_LOCKED | EXTENT_WRITEBACK,
2707 0, NULL)) {
2708 remove_extent_mapping(map, em);
2709 /* once for the rb tree */
2710 free_extent_map(em);
2711 }
2712 start = extent_map_end(em);
2713 write_unlock(&map->lock);
2714
2715 /* once for us */
2716 free_extent_map(em);
2717 }
2718 }
2719 return try_release_extent_state(map, tree, page, mask);
2720}
2721
2722/*
2723 * helper function for fiemap, which doesn't want to see any holes.
2724 * This maps until we find something past 'last'
2725 */
2726static struct extent_map *get_extent_skip_holes(struct inode *inode,
2727 u64 offset,
2728 u64 last,
2729 get_extent_t *get_extent)
2730{
2731 u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
2732 struct extent_map *em;
2733 u64 len;
2734
2735 if (offset >= last)
2736 return NULL;
2737
2738 while(1) {
2739 len = last - offset;
2740 if (len == 0)
2741 break;
2742 len = (len + sectorsize - 1) & ~(sectorsize - 1);
2743 em = get_extent(inode, NULL, 0, offset, len, 0);
2744 if (IS_ERR_OR_NULL(em))
2745 return em;
2746
2747 /* if this isn't a hole return it */
2748 if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
2749 em->block_start != EXTENT_MAP_HOLE) {
2750 return em;
2751 }
2752
2753 /* this is a hole, advance to the next extent */
2754 offset = extent_map_end(em);
2755 free_extent_map(em);
2756 if (offset >= last)
2757 break;
2758 }
2759 return NULL;
2760}
2761
2762int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
2763 __u64 start, __u64 len, get_extent_t *get_extent)
2764{
2765 int ret = 0;
2766 u64 off = start;
2767 u64 max = start + len;
2768 u32 flags = 0;
2769 u32 found_type;
2770 u64 last;
2771 u64 last_for_get_extent = 0;
2772 u64 disko = 0;
2773 u64 isize = i_size_read(inode);
2774 struct btrfs_key found_key;
2775 struct extent_map *em = NULL;
2776 struct extent_state *cached_state = NULL;
2777 struct btrfs_path *path;
2778 struct btrfs_file_extent_item *item;
2779 int end = 0;
2780 u64 em_start = 0;
2781 u64 em_len = 0;
2782 u64 em_end = 0;
2783 unsigned long emflags;
2784
2785 if (len == 0)
2786 return -EINVAL;
2787
2788 path = btrfs_alloc_path();
2789 if (!path)
2790 return -ENOMEM;
2791 path->leave_spinning = 1;
2792
2793 /*
2794 * lookup the last file extent. We're not using i_size here
2795 * because there might be preallocation past i_size
2796 */
2797 ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
2798 path, btrfs_ino(inode), -1, 0);
2799 if (ret < 0) {
2800 btrfs_free_path(path);
2801 return ret;
2802 }
2803 WARN_ON(!ret);
2804 path->slots[0]--;
2805 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2806 struct btrfs_file_extent_item);
2807 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
2808 found_type = btrfs_key_type(&found_key);
2809
2810 /* No extents, but there might be delalloc bits */
2811 if (found_key.objectid != btrfs_ino(inode) ||
2812 found_type != BTRFS_EXTENT_DATA_KEY) {
2813 /* have to trust i_size as the end */
2814 last = (u64)-1;
2815 last_for_get_extent = isize;
2816 } else {
2817 /*
2818 * remember the start of the last extent. There are a
2819 * bunch of different factors that go into the length of the
2820 * extent, so its much less complex to remember where it started
2821 */
2822 last = found_key.offset;
2823 last_for_get_extent = last + 1;
2824 }
2825 btrfs_free_path(path);
2826
2827 /*
2828 * we might have some extents allocated but more delalloc past those
2829 * extents. so, we trust isize unless the start of the last extent is
2830 * beyond isize
2831 */
2832 if (last < isize) {
2833 last = (u64)-1;
2834 last_for_get_extent = isize;
2835 }
2836
2837 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
2838 &cached_state, GFP_NOFS);
2839
2840 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2841 get_extent);
2842 if (!em)
2843 goto out;
2844 if (IS_ERR(em)) {
2845 ret = PTR_ERR(em);
2846 goto out;
2847 }
2848
2849 while (!end) {
2850 u64 offset_in_extent;
2851
2852 /* break if the extent we found is outside the range */
2853 if (em->start >= max || extent_map_end(em) < off)
2854 break;
2855
2856 /*
2857 * get_extent may return an extent that starts before our
2858 * requested range. We have to make sure the ranges
2859 * we return to fiemap always move forward and don't
2860 * overlap, so adjust the offsets here
2861 */
2862 em_start = max(em->start, off);
2863
2864 /*
2865 * record the offset from the start of the extent
2866 * for adjusting the disk offset below
2867 */
2868 offset_in_extent = em_start - em->start;
2869 em_end = extent_map_end(em);
2870 em_len = em_end - em_start;
2871 emflags = em->flags;
2872 disko = 0;
2873 flags = 0;
2874
2875 /*
2876 * bump off for our next call to get_extent
2877 */
2878 off = extent_map_end(em);
2879 if (off >= max)
2880 end = 1;
2881
2882 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
2883 end = 1;
2884 flags |= FIEMAP_EXTENT_LAST;
2885 } else if (em->block_start == EXTENT_MAP_INLINE) {
2886 flags |= (FIEMAP_EXTENT_DATA_INLINE |
2887 FIEMAP_EXTENT_NOT_ALIGNED);
2888 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
2889 flags |= (FIEMAP_EXTENT_DELALLOC |
2890 FIEMAP_EXTENT_UNKNOWN);
2891 } else {
2892 disko = em->block_start + offset_in_extent;
2893 }
2894 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
2895 flags |= FIEMAP_EXTENT_ENCODED;
2896
2897 free_extent_map(em);
2898 em = NULL;
2899 if ((em_start >= last) || em_len == (u64)-1 ||
2900 (last == (u64)-1 && isize <= em_end)) {
2901 flags |= FIEMAP_EXTENT_LAST;
2902 end = 1;
2903 }
2904
2905 /* now scan forward to see if this is really the last extent. */
2906 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2907 get_extent);
2908 if (IS_ERR(em)) {
2909 ret = PTR_ERR(em);
2910 goto out;
2911 }
2912 if (!em) {
2913 flags |= FIEMAP_EXTENT_LAST;
2914 end = 1;
2915 }
2916 ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
2917 em_len, flags);
2918 if (ret)
2919 goto out_free;
2920 }
2921out_free:
2922 free_extent_map(em);
2923out:
2924 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len,
2925 &cached_state, GFP_NOFS);
2926 return ret;
2927}
2928
2929static inline struct page *extent_buffer_page(struct extent_buffer *eb,
2930 unsigned long i)
2931{
2932 struct page *p;
2933 struct address_space *mapping;
2934
2935 if (i == 0)
2936 return eb->first_page;
2937 i += eb->start >> PAGE_CACHE_SHIFT;
2938 mapping = eb->first_page->mapping;
2939 if (!mapping)
2940 return NULL;
2941
2942 /*
2943 * extent_buffer_page is only called after pinning the page
2944 * by increasing the reference count. So we know the page must
2945 * be in the radix tree.
2946 */
2947 rcu_read_lock();
2948 p = radix_tree_lookup(&mapping->page_tree, i);
2949 rcu_read_unlock();
2950
2951 return p;
2952}
2953
2954static inline unsigned long num_extent_pages(u64 start, u64 len)
2955{
2956 return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
2957 (start >> PAGE_CACHE_SHIFT);
2958}
2959
2960static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
2961 u64 start,
2962 unsigned long len,
2963 gfp_t mask)
2964{
2965 struct extent_buffer *eb = NULL;
2966#if LEAK_DEBUG
2967 unsigned long flags;
2968#endif
2969
2970 eb = kmem_cache_zalloc(extent_buffer_cache, mask);
2971 if (eb == NULL)
2972 return NULL;
2973 eb->start = start;
2974 eb->len = len;
2975 rwlock_init(&eb->lock);
2976 atomic_set(&eb->write_locks, 0);
2977 atomic_set(&eb->read_locks, 0);
2978 atomic_set(&eb->blocking_readers, 0);
2979 atomic_set(&eb->blocking_writers, 0);
2980 atomic_set(&eb->spinning_readers, 0);
2981 atomic_set(&eb->spinning_writers, 0);
2982 init_waitqueue_head(&eb->write_lock_wq);
2983 init_waitqueue_head(&eb->read_lock_wq);
2984
2985#if LEAK_DEBUG
2986 spin_lock_irqsave(&leak_lock, flags);
2987 list_add(&eb->leak_list, &buffers);
2988 spin_unlock_irqrestore(&leak_lock, flags);
2989#endif
2990 atomic_set(&eb->refs, 1);
2991
2992 return eb;
2993}
2994
2995static void __free_extent_buffer(struct extent_buffer *eb)
2996{
2997#if LEAK_DEBUG
2998 unsigned long flags;
2999 spin_lock_irqsave(&leak_lock, flags);
3000 list_del(&eb->leak_list);
3001 spin_unlock_irqrestore(&leak_lock, flags);
3002#endif
3003 kmem_cache_free(extent_buffer_cache, eb);
3004}
3005
3006/*
3007 * Helper for releasing extent buffer page.
3008 */
3009static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
3010 unsigned long start_idx)
3011{
3012 unsigned long index;
3013 struct page *page;
3014
3015 if (!eb->first_page)
3016 return;
3017
3018 index = num_extent_pages(eb->start, eb->len);
3019 if (start_idx >= index)
3020 return;
3021
3022 do {
3023 index--;
3024 page = extent_buffer_page(eb, index);
3025 if (page)
3026 page_cache_release(page);
3027 } while (index != start_idx);
3028}
3029
3030/*
3031 * Helper for releasing the extent buffer.
3032 */
3033static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
3034{
3035 btrfs_release_extent_buffer_page(eb, 0);
3036 __free_extent_buffer(eb);
3037}
3038
3039struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
3040 u64 start, unsigned long len,
3041 struct page *page0)
3042{
3043 unsigned long num_pages = num_extent_pages(start, len);
3044 unsigned long i;
3045 unsigned long index = start >> PAGE_CACHE_SHIFT;
3046 struct extent_buffer *eb;
3047 struct extent_buffer *exists = NULL;
3048 struct page *p;
3049 struct address_space *mapping = tree->mapping;
3050 int uptodate = 1;
3051 int ret;
3052
3053 rcu_read_lock();
3054 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3055 if (eb && atomic_inc_not_zero(&eb->refs)) {
3056 rcu_read_unlock();
3057 mark_page_accessed(eb->first_page);
3058 return eb;
3059 }
3060 rcu_read_unlock();
3061
3062 eb = __alloc_extent_buffer(tree, start, len, GFP_NOFS);
3063 if (!eb)
3064 return NULL;
3065
3066 if (page0) {
3067 eb->first_page = page0;
3068 i = 1;
3069 index++;
3070 page_cache_get(page0);
3071 mark_page_accessed(page0);
3072 set_page_extent_mapped(page0);
3073 set_page_extent_head(page0, len);
3074 uptodate = PageUptodate(page0);
3075 } else {
3076 i = 0;
3077 }
3078 for (; i < num_pages; i++, index++) {
3079 p = find_or_create_page(mapping, index, GFP_NOFS);
3080 if (!p) {
3081 WARN_ON(1);
3082 goto free_eb;
3083 }
3084 set_page_extent_mapped(p);
3085 mark_page_accessed(p);
3086 if (i == 0) {
3087 eb->first_page = p;
3088 set_page_extent_head(p, len);
3089 } else {
3090 set_page_private(p, EXTENT_PAGE_PRIVATE);
3091 }
3092 if (!PageUptodate(p))
3093 uptodate = 0;
3094
3095 /*
3096 * see below about how we avoid a nasty race with release page
3097 * and why we unlock later
3098 */
3099 if (i != 0)
3100 unlock_page(p);
3101 }
3102 if (uptodate)
3103 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3104
3105 ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
3106 if (ret)
3107 goto free_eb;
3108
3109 spin_lock(&tree->buffer_lock);
3110 ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
3111 if (ret == -EEXIST) {
3112 exists = radix_tree_lookup(&tree->buffer,
3113 start >> PAGE_CACHE_SHIFT);
3114 /* add one reference for the caller */
3115 atomic_inc(&exists->refs);
3116 spin_unlock(&tree->buffer_lock);
3117 radix_tree_preload_end();
3118 goto free_eb;
3119 }
3120 /* add one reference for the tree */
3121 atomic_inc(&eb->refs);
3122 spin_unlock(&tree->buffer_lock);
3123 radix_tree_preload_end();
3124
3125 /*
3126 * there is a race where release page may have
3127 * tried to find this extent buffer in the radix
3128 * but failed. It will tell the VM it is safe to
3129 * reclaim the, and it will clear the page private bit.
3130 * We must make sure to set the page private bit properly
3131 * after the extent buffer is in the radix tree so
3132 * it doesn't get lost
3133 */
3134 set_page_extent_mapped(eb->first_page);
3135 set_page_extent_head(eb->first_page, eb->len);
3136 if (!page0)
3137 unlock_page(eb->first_page);
3138 return eb;
3139
3140free_eb:
3141 if (eb->first_page && !page0)
3142 unlock_page(eb->first_page);
3143
3144 if (!atomic_dec_and_test(&eb->refs))
3145 return exists;
3146 btrfs_release_extent_buffer(eb);
3147 return exists;
3148}
3149
3150struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
3151 u64 start, unsigned long len)
3152{
3153 struct extent_buffer *eb;
3154
3155 rcu_read_lock();
3156 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3157 if (eb && atomic_inc_not_zero(&eb->refs)) {
3158 rcu_read_unlock();
3159 mark_page_accessed(eb->first_page);
3160 return eb;
3161 }
3162 rcu_read_unlock();
3163
3164 return NULL;
3165}
3166
3167void free_extent_buffer(struct extent_buffer *eb)
3168{
3169 if (!eb)
3170 return;
3171
3172 if (!atomic_dec_and_test(&eb->refs))
3173 return;
3174
3175 WARN_ON(1);
3176}
3177
3178int clear_extent_buffer_dirty(struct extent_io_tree *tree,
3179 struct extent_buffer *eb)
3180{
3181 unsigned long i;
3182 unsigned long num_pages;
3183 struct page *page;
3184
3185 num_pages = num_extent_pages(eb->start, eb->len);
3186
3187 for (i = 0; i < num_pages; i++) {
3188 page = extent_buffer_page(eb, i);
3189 if (!PageDirty(page))
3190 continue;
3191
3192 lock_page(page);
3193 WARN_ON(!PagePrivate(page));
3194
3195 set_page_extent_mapped(page);
3196 if (i == 0)
3197 set_page_extent_head(page, eb->len);
3198
3199 clear_page_dirty_for_io(page);
3200 spin_lock_irq(&page->mapping->tree_lock);
3201 if (!PageDirty(page)) {
3202 radix_tree_tag_clear(&page->mapping->page_tree,
3203 page_index(page),
3204 PAGECACHE_TAG_DIRTY);
3205 }
3206 spin_unlock_irq(&page->mapping->tree_lock);
3207 unlock_page(page);
3208 }
3209 return 0;
3210}
3211
3212int set_extent_buffer_dirty(struct extent_io_tree *tree,
3213 struct extent_buffer *eb)
3214{
3215 unsigned long i;
3216 unsigned long num_pages;
3217 int was_dirty = 0;
3218
3219 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
3220 num_pages = num_extent_pages(eb->start, eb->len);
3221 for (i = 0; i < num_pages; i++)
3222 __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3223 return was_dirty;
3224}
3225
3226static int __eb_straddles_pages(u64 start, u64 len)
3227{
3228 if (len < PAGE_CACHE_SIZE)
3229 return 1;
3230 if (start & (PAGE_CACHE_SIZE - 1))
3231 return 1;
3232 if ((start + len) & (PAGE_CACHE_SIZE - 1))
3233 return 1;
3234 return 0;
3235}
3236
3237static int eb_straddles_pages(struct extent_buffer *eb)
3238{
3239 return __eb_straddles_pages(eb->start, eb->len);
3240}
3241
3242int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3243 struct extent_buffer *eb,
3244 struct extent_state **cached_state)
3245{
3246 unsigned long i;
3247 struct page *page;
3248 unsigned long num_pages;
3249
3250 num_pages = num_extent_pages(eb->start, eb->len);
3251 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3252
3253 if (eb_straddles_pages(eb)) {
3254 clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3255 cached_state, GFP_NOFS);
3256 }
3257 for (i = 0; i < num_pages; i++) {
3258 page = extent_buffer_page(eb, i);
3259 if (page)
3260 ClearPageUptodate(page);
3261 }
3262 return 0;
3263}
3264
3265int set_extent_buffer_uptodate(struct extent_io_tree *tree,
3266 struct extent_buffer *eb)
3267{
3268 unsigned long i;
3269 struct page *page;
3270 unsigned long num_pages;
3271
3272 num_pages = num_extent_pages(eb->start, eb->len);
3273
3274 if (eb_straddles_pages(eb)) {
3275 set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3276 NULL, GFP_NOFS);
3277 }
3278 for (i = 0; i < num_pages; i++) {
3279 page = extent_buffer_page(eb, i);
3280 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3281 ((i == num_pages - 1) &&
3282 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3283 check_page_uptodate(tree, page);
3284 continue;
3285 }
3286 SetPageUptodate(page);
3287 }
3288 return 0;
3289}
3290
3291int extent_range_uptodate(struct extent_io_tree *tree,
3292 u64 start, u64 end)
3293{
3294 struct page *page;
3295 int ret;
3296 int pg_uptodate = 1;
3297 int uptodate;
3298 unsigned long index;
3299
3300 if (__eb_straddles_pages(start, end - start + 1)) {
3301 ret = test_range_bit(tree, start, end,
3302 EXTENT_UPTODATE, 1, NULL);
3303 if (ret)
3304 return 1;
3305 }
3306 while (start <= end) {
3307 index = start >> PAGE_CACHE_SHIFT;
3308 page = find_get_page(tree->mapping, index);
3309 uptodate = PageUptodate(page);
3310 page_cache_release(page);
3311 if (!uptodate) {
3312 pg_uptodate = 0;
3313 break;
3314 }
3315 start += PAGE_CACHE_SIZE;
3316 }
3317 return pg_uptodate;
3318}
3319
3320int extent_buffer_uptodate(struct extent_io_tree *tree,
3321 struct extent_buffer *eb,
3322 struct extent_state *cached_state)
3323{
3324 int ret = 0;
3325 unsigned long num_pages;
3326 unsigned long i;
3327 struct page *page;
3328 int pg_uptodate = 1;
3329
3330 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3331 return 1;
3332
3333 if (eb_straddles_pages(eb)) {
3334 ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3335 EXTENT_UPTODATE, 1, cached_state);
3336 if (ret)
3337 return ret;
3338 }
3339
3340 num_pages = num_extent_pages(eb->start, eb->len);
3341 for (i = 0; i < num_pages; i++) {
3342 page = extent_buffer_page(eb, i);
3343 if (!PageUptodate(page)) {
3344 pg_uptodate = 0;
3345 break;
3346 }
3347 }
3348 return pg_uptodate;
3349}
3350
3351int read_extent_buffer_pages(struct extent_io_tree *tree,
3352 struct extent_buffer *eb,
3353 u64 start, int wait,
3354 get_extent_t *get_extent, int mirror_num)
3355{
3356 unsigned long i;
3357 unsigned long start_i;
3358 struct page *page;
3359 int err;
3360 int ret = 0;
3361 int locked_pages = 0;
3362 int all_uptodate = 1;
3363 int inc_all_pages = 0;
3364 unsigned long num_pages;
3365 struct bio *bio = NULL;
3366 unsigned long bio_flags = 0;
3367
3368 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3369 return 0;
3370
3371 if (eb_straddles_pages(eb)) {
3372 if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3373 EXTENT_UPTODATE, 1, NULL)) {
3374 return 0;
3375 }
3376 }
3377
3378 if (start) {
3379 WARN_ON(start < eb->start);
3380 start_i = (start >> PAGE_CACHE_SHIFT) -
3381 (eb->start >> PAGE_CACHE_SHIFT);
3382 } else {
3383 start_i = 0;
3384 }
3385
3386 num_pages = num_extent_pages(eb->start, eb->len);
3387 for (i = start_i; i < num_pages; i++) {
3388 page = extent_buffer_page(eb, i);
3389 if (!wait) {
3390 if (!trylock_page(page))
3391 goto unlock_exit;
3392 } else {
3393 lock_page(page);
3394 }
3395 locked_pages++;
3396 if (!PageUptodate(page))
3397 all_uptodate = 0;
3398 }
3399 if (all_uptodate) {
3400 if (start_i == 0)
3401 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3402 goto unlock_exit;
3403 }
3404
3405 for (i = start_i; i < num_pages; i++) {
3406 page = extent_buffer_page(eb, i);
3407
3408 WARN_ON(!PagePrivate(page));
3409
3410 set_page_extent_mapped(page);
3411 if (i == 0)
3412 set_page_extent_head(page, eb->len);
3413
3414 if (inc_all_pages)
3415 page_cache_get(page);
3416 if (!PageUptodate(page)) {
3417 if (start_i == 0)
3418 inc_all_pages = 1;
3419 ClearPageError(page);
3420 err = __extent_read_full_page(tree, page,
3421 get_extent, &bio,
3422 mirror_num, &bio_flags);
3423 if (err)
3424 ret = err;
3425 } else {
3426 unlock_page(page);
3427 }
3428 }
3429
3430 if (bio)
3431 submit_one_bio(READ, bio, mirror_num, bio_flags);
3432
3433 if (ret || !wait)
3434 return ret;
3435
3436 for (i = start_i; i < num_pages; i++) {
3437 page = extent_buffer_page(eb, i);
3438 wait_on_page_locked(page);
3439 if (!PageUptodate(page))
3440 ret = -EIO;
3441 }
3442
3443 if (!ret)
3444 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3445 return ret;
3446
3447unlock_exit:
3448 i = start_i;
3449 while (locked_pages > 0) {
3450 page = extent_buffer_page(eb, i);
3451 i++;
3452 unlock_page(page);
3453 locked_pages--;
3454 }
3455 return ret;
3456}
3457
3458void read_extent_buffer(struct extent_buffer *eb, void *dstv,
3459 unsigned long start,
3460 unsigned long len)
3461{
3462 size_t cur;
3463 size_t offset;
3464 struct page *page;
3465 char *kaddr;
3466 char *dst = (char *)dstv;
3467 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3468 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3469
3470 WARN_ON(start > eb->len);
3471 WARN_ON(start + len > eb->start + eb->len);
3472
3473 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3474
3475 while (len > 0) {
3476 page = extent_buffer_page(eb, i);
3477
3478 cur = min(len, (PAGE_CACHE_SIZE - offset));
3479 kaddr = page_address(page);
3480 memcpy(dst, kaddr + offset, cur);
3481
3482 dst += cur;
3483 len -= cur;
3484 offset = 0;
3485 i++;
3486 }
3487}
3488
3489int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
3490 unsigned long min_len, char **map,
3491 unsigned long *map_start,
3492 unsigned long *map_len)
3493{
3494 size_t offset = start & (PAGE_CACHE_SIZE - 1);
3495 char *kaddr;
3496 struct page *p;
3497 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3498 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3499 unsigned long end_i = (start_offset + start + min_len - 1) >>
3500 PAGE_CACHE_SHIFT;
3501
3502 if (i != end_i)
3503 return -EINVAL;
3504
3505 if (i == 0) {
3506 offset = start_offset;
3507 *map_start = 0;
3508 } else {
3509 offset = 0;
3510 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
3511 }
3512
3513 if (start + min_len > eb->len) {
3514 printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
3515 "wanted %lu %lu\n", (unsigned long long)eb->start,
3516 eb->len, start, min_len);
3517 WARN_ON(1);
3518 return -EINVAL;
3519 }
3520
3521 p = extent_buffer_page(eb, i);
3522 kaddr = page_address(p);
3523 *map = kaddr + offset;
3524 *map_len = PAGE_CACHE_SIZE - offset;
3525 return 0;
3526}
3527
3528int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
3529 unsigned long start,
3530 unsigned long len)
3531{
3532 size_t cur;
3533 size_t offset;
3534 struct page *page;
3535 char *kaddr;
3536 char *ptr = (char *)ptrv;
3537 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3538 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3539 int ret = 0;
3540
3541 WARN_ON(start > eb->len);
3542 WARN_ON(start + len > eb->start + eb->len);
3543
3544 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3545
3546 while (len > 0) {
3547 page = extent_buffer_page(eb, i);
3548
3549 cur = min(len, (PAGE_CACHE_SIZE - offset));
3550
3551 kaddr = page_address(page);
3552 ret = memcmp(ptr, kaddr + offset, cur);
3553 if (ret)
3554 break;
3555
3556 ptr += cur;
3557 len -= cur;
3558 offset = 0;
3559 i++;
3560 }
3561 return ret;
3562}
3563
3564void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
3565 unsigned long start, unsigned long len)
3566{
3567 size_t cur;
3568 size_t offset;
3569 struct page *page;
3570 char *kaddr;
3571 char *src = (char *)srcv;
3572 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3573 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3574
3575 WARN_ON(start > eb->len);
3576 WARN_ON(start + len > eb->start + eb->len);
3577
3578 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3579
3580 while (len > 0) {
3581 page = extent_buffer_page(eb, i);
3582 WARN_ON(!PageUptodate(page));
3583
3584 cur = min(len, PAGE_CACHE_SIZE - offset);
3585 kaddr = page_address(page);
3586 memcpy(kaddr + offset, src, cur);
3587
3588 src += cur;
3589 len -= cur;
3590 offset = 0;
3591 i++;
3592 }
3593}
3594
3595void memset_extent_buffer(struct extent_buffer *eb, char c,
3596 unsigned long start, unsigned long len)
3597{
3598 size_t cur;
3599 size_t offset;
3600 struct page *page;
3601 char *kaddr;
3602 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3603 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3604
3605 WARN_ON(start > eb->len);
3606 WARN_ON(start + len > eb->start + eb->len);
3607
3608 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3609
3610 while (len > 0) {
3611 page = extent_buffer_page(eb, i);
3612 WARN_ON(!PageUptodate(page));
3613
3614 cur = min(len, PAGE_CACHE_SIZE - offset);
3615 kaddr = page_address(page);
3616 memset(kaddr + offset, c, cur);
3617
3618 len -= cur;
3619 offset = 0;
3620 i++;
3621 }
3622}
3623
3624void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
3625 unsigned long dst_offset, unsigned long src_offset,
3626 unsigned long len)
3627{
3628 u64 dst_len = dst->len;
3629 size_t cur;
3630 size_t offset;
3631 struct page *page;
3632 char *kaddr;
3633 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3634 unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3635
3636 WARN_ON(src->len != dst_len);
3637
3638 offset = (start_offset + dst_offset) &
3639 ((unsigned long)PAGE_CACHE_SIZE - 1);
3640
3641 while (len > 0) {
3642 page = extent_buffer_page(dst, i);
3643 WARN_ON(!PageUptodate(page));
3644
3645 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
3646
3647 kaddr = page_address(page);
3648 read_extent_buffer(src, kaddr + offset, src_offset, cur);
3649
3650 src_offset += cur;
3651 len -= cur;
3652 offset = 0;
3653 i++;
3654 }
3655}
3656
3657static void move_pages(struct page *dst_page, struct page *src_page,
3658 unsigned long dst_off, unsigned long src_off,
3659 unsigned long len)
3660{
3661 char *dst_kaddr = page_address(dst_page);
3662 if (dst_page == src_page) {
3663 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
3664 } else {
3665 char *src_kaddr = page_address(src_page);
3666 char *p = dst_kaddr + dst_off + len;
3667 char *s = src_kaddr + src_off + len;
3668
3669 while (len--)
3670 *--p = *--s;
3671 }
3672}
3673
3674static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
3675{
3676 unsigned long distance = (src > dst) ? src - dst : dst - src;
3677 return distance < len;
3678}
3679
3680static void copy_pages(struct page *dst_page, struct page *src_page,
3681 unsigned long dst_off, unsigned long src_off,
3682 unsigned long len)
3683{
3684 char *dst_kaddr = page_address(dst_page);
3685 char *src_kaddr;
3686
3687 if (dst_page != src_page) {
3688 src_kaddr = page_address(src_page);
3689 } else {
3690 src_kaddr = dst_kaddr;
3691 BUG_ON(areas_overlap(src_off, dst_off, len));
3692 }
3693
3694 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
3695}
3696
3697void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3698 unsigned long src_offset, unsigned long len)
3699{
3700 size_t cur;
3701 size_t dst_off_in_page;
3702 size_t src_off_in_page;
3703 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3704 unsigned long dst_i;
3705 unsigned long src_i;
3706
3707 if (src_offset + len > dst->len) {
3708 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3709 "len %lu dst len %lu\n", src_offset, len, dst->len);
3710 BUG_ON(1);
3711 }
3712 if (dst_offset + len > dst->len) {
3713 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3714 "len %lu dst len %lu\n", dst_offset, len, dst->len);
3715 BUG_ON(1);
3716 }
3717
3718 while (len > 0) {
3719 dst_off_in_page = (start_offset + dst_offset) &
3720 ((unsigned long)PAGE_CACHE_SIZE - 1);
3721 src_off_in_page = (start_offset + src_offset) &
3722 ((unsigned long)PAGE_CACHE_SIZE - 1);
3723
3724 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3725 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
3726
3727 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
3728 src_off_in_page));
3729 cur = min_t(unsigned long, cur,
3730 (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
3731
3732 copy_pages(extent_buffer_page(dst, dst_i),
3733 extent_buffer_page(dst, src_i),
3734 dst_off_in_page, src_off_in_page, cur);
3735
3736 src_offset += cur;
3737 dst_offset += cur;
3738 len -= cur;
3739 }
3740}
3741
3742void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3743 unsigned long src_offset, unsigned long len)
3744{
3745 size_t cur;
3746 size_t dst_off_in_page;
3747 size_t src_off_in_page;
3748 unsigned long dst_end = dst_offset + len - 1;
3749 unsigned long src_end = src_offset + len - 1;
3750 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3751 unsigned long dst_i;
3752 unsigned long src_i;
3753
3754 if (src_offset + len > dst->len) {
3755 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3756 "len %lu len %lu\n", src_offset, len, dst->len);
3757 BUG_ON(1);
3758 }
3759 if (dst_offset + len > dst->len) {
3760 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3761 "len %lu len %lu\n", dst_offset, len, dst->len);
3762 BUG_ON(1);
3763 }
3764 if (!areas_overlap(src_offset, dst_offset, len)) {
3765 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
3766 return;
3767 }
3768 while (len > 0) {
3769 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
3770 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
3771
3772 dst_off_in_page = (start_offset + dst_end) &
3773 ((unsigned long)PAGE_CACHE_SIZE - 1);
3774 src_off_in_page = (start_offset + src_end) &
3775 ((unsigned long)PAGE_CACHE_SIZE - 1);
3776
3777 cur = min_t(unsigned long, len, src_off_in_page + 1);
3778 cur = min(cur, dst_off_in_page + 1);
3779 move_pages(extent_buffer_page(dst, dst_i),
3780 extent_buffer_page(dst, src_i),
3781 dst_off_in_page - cur + 1,
3782 src_off_in_page - cur + 1, cur);
3783
3784 dst_end -= cur;
3785 src_end -= cur;
3786 len -= cur;
3787 }
3788}
3789
3790static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
3791{
3792 struct extent_buffer *eb =
3793 container_of(head, struct extent_buffer, rcu_head);
3794
3795 btrfs_release_extent_buffer(eb);
3796}
3797
3798int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
3799{
3800 u64 start = page_offset(page);
3801 struct extent_buffer *eb;
3802 int ret = 1;
3803
3804 spin_lock(&tree->buffer_lock);
3805 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3806 if (!eb) {
3807 spin_unlock(&tree->buffer_lock);
3808 return ret;
3809 }
3810
3811 if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3812 ret = 0;
3813 goto out;
3814 }
3815
3816 /*
3817 * set @eb->refs to 0 if it is already 1, and then release the @eb.
3818 * Or go back.
3819 */
3820 if (atomic_cmpxchg(&eb->refs, 1, 0) != 1) {
3821 ret = 0;
3822 goto out;
3823 }
3824
3825 radix_tree_delete(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3826out:
3827 spin_unlock(&tree->buffer_lock);
3828
3829 /* at this point we can safely release the extent buffer */
3830 if (atomic_read(&eb->refs) == 0)
3831 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
3832 return ret;
3833}
1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/bitops.h>
4#include <linux/slab.h>
5#include <linux/bio.h>
6#include <linux/mm.h>
7#include <linux/pagemap.h>
8#include <linux/page-flags.h>
9#include <linux/sched/mm.h>
10#include <linux/spinlock.h>
11#include <linux/blkdev.h>
12#include <linux/swap.h>
13#include <linux/writeback.h>
14#include <linux/pagevec.h>
15#include <linux/prefetch.h>
16#include <linux/fsverity.h>
17#include "misc.h"
18#include "extent_io.h"
19#include "extent-io-tree.h"
20#include "extent_map.h"
21#include "ctree.h"
22#include "btrfs_inode.h"
23#include "bio.h"
24#include "check-integrity.h"
25#include "locking.h"
26#include "rcu-string.h"
27#include "backref.h"
28#include "disk-io.h"
29#include "subpage.h"
30#include "zoned.h"
31#include "block-group.h"
32#include "compression.h"
33#include "fs.h"
34#include "accessors.h"
35#include "file-item.h"
36#include "file.h"
37#include "dev-replace.h"
38#include "super.h"
39
40static struct kmem_cache *extent_buffer_cache;
41
42#ifdef CONFIG_BTRFS_DEBUG
43static inline void btrfs_leak_debug_add_eb(struct extent_buffer *eb)
44{
45 struct btrfs_fs_info *fs_info = eb->fs_info;
46 unsigned long flags;
47
48 spin_lock_irqsave(&fs_info->eb_leak_lock, flags);
49 list_add(&eb->leak_list, &fs_info->allocated_ebs);
50 spin_unlock_irqrestore(&fs_info->eb_leak_lock, flags);
51}
52
53static inline void btrfs_leak_debug_del_eb(struct extent_buffer *eb)
54{
55 struct btrfs_fs_info *fs_info = eb->fs_info;
56 unsigned long flags;
57
58 spin_lock_irqsave(&fs_info->eb_leak_lock, flags);
59 list_del(&eb->leak_list);
60 spin_unlock_irqrestore(&fs_info->eb_leak_lock, flags);
61}
62
63void btrfs_extent_buffer_leak_debug_check(struct btrfs_fs_info *fs_info)
64{
65 struct extent_buffer *eb;
66 unsigned long flags;
67
68 /*
69 * If we didn't get into open_ctree our allocated_ebs will not be
70 * initialized, so just skip this.
71 */
72 if (!fs_info->allocated_ebs.next)
73 return;
74
75 WARN_ON(!list_empty(&fs_info->allocated_ebs));
76 spin_lock_irqsave(&fs_info->eb_leak_lock, flags);
77 while (!list_empty(&fs_info->allocated_ebs)) {
78 eb = list_first_entry(&fs_info->allocated_ebs,
79 struct extent_buffer, leak_list);
80 pr_err(
81 "BTRFS: buffer leak start %llu len %lu refs %d bflags %lu owner %llu\n",
82 eb->start, eb->len, atomic_read(&eb->refs), eb->bflags,
83 btrfs_header_owner(eb));
84 list_del(&eb->leak_list);
85 kmem_cache_free(extent_buffer_cache, eb);
86 }
87 spin_unlock_irqrestore(&fs_info->eb_leak_lock, flags);
88}
89#else
90#define btrfs_leak_debug_add_eb(eb) do {} while (0)
91#define btrfs_leak_debug_del_eb(eb) do {} while (0)
92#endif
93
94/*
95 * Structure to record info about the bio being assembled, and other info like
96 * how many bytes are there before stripe/ordered extent boundary.
97 */
98struct btrfs_bio_ctrl {
99 struct bio *bio;
100 int mirror_num;
101 enum btrfs_compression_type compress_type;
102 u32 len_to_stripe_boundary;
103 u32 len_to_oe_boundary;
104 btrfs_bio_end_io_t end_io_func;
105
106 /*
107 * This is for metadata read, to provide the extra needed verification
108 * info. This has to be provided for submit_one_bio(), as
109 * submit_one_bio() can submit a bio if it ends at stripe boundary. If
110 * no such parent_check is provided, the metadata can hit false alert at
111 * endio time.
112 */
113 struct btrfs_tree_parent_check *parent_check;
114
115 /*
116 * Tell writepage not to lock the state bits for this range, it still
117 * does the unlocking.
118 */
119 bool extent_locked;
120
121 /* Tell the submit_bio code to use REQ_SYNC */
122 bool sync_io;
123};
124
125static void submit_one_bio(struct btrfs_bio_ctrl *bio_ctrl)
126{
127 struct bio *bio;
128 struct bio_vec *bv;
129 struct btrfs_inode *inode;
130 int mirror_num;
131
132 if (!bio_ctrl->bio)
133 return;
134
135 bio = bio_ctrl->bio;
136 bv = bio_first_bvec_all(bio);
137 inode = BTRFS_I(bv->bv_page->mapping->host);
138 mirror_num = bio_ctrl->mirror_num;
139
140 /* Caller should ensure the bio has at least some range added */
141 ASSERT(bio->bi_iter.bi_size);
142
143 btrfs_bio(bio)->file_offset = page_offset(bv->bv_page) + bv->bv_offset;
144
145 if (!is_data_inode(&inode->vfs_inode)) {
146 if (btrfs_op(bio) != BTRFS_MAP_WRITE) {
147 /*
148 * For metadata read, we should have the parent_check,
149 * and copy it to bbio for metadata verification.
150 */
151 ASSERT(bio_ctrl->parent_check);
152 memcpy(&btrfs_bio(bio)->parent_check,
153 bio_ctrl->parent_check,
154 sizeof(struct btrfs_tree_parent_check));
155 }
156 btrfs_submit_metadata_bio(inode, bio, mirror_num);
157 } else if (btrfs_op(bio) == BTRFS_MAP_WRITE) {
158 btrfs_submit_data_write_bio(inode, bio, mirror_num);
159 } else {
160 btrfs_submit_data_read_bio(inode, bio, mirror_num,
161 bio_ctrl->compress_type);
162 }
163
164 /* The bio is owned by the end_io handler now */
165 bio_ctrl->bio = NULL;
166}
167
168/*
169 * Submit or fail the current bio in the bio_ctrl structure.
170 */
171static void submit_write_bio(struct btrfs_bio_ctrl *bio_ctrl, int ret)
172{
173 struct bio *bio = bio_ctrl->bio;
174
175 if (!bio)
176 return;
177
178 if (ret) {
179 ASSERT(ret < 0);
180 btrfs_bio_end_io(btrfs_bio(bio), errno_to_blk_status(ret));
181 /* The bio is owned by the end_io handler now */
182 bio_ctrl->bio = NULL;
183 } else {
184 submit_one_bio(bio_ctrl);
185 }
186}
187
188int __init extent_buffer_init_cachep(void)
189{
190 extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
191 sizeof(struct extent_buffer), 0,
192 SLAB_MEM_SPREAD, NULL);
193 if (!extent_buffer_cache)
194 return -ENOMEM;
195
196 return 0;
197}
198
199void __cold extent_buffer_free_cachep(void)
200{
201 /*
202 * Make sure all delayed rcu free are flushed before we
203 * destroy caches.
204 */
205 rcu_barrier();
206 kmem_cache_destroy(extent_buffer_cache);
207}
208
209void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
210{
211 unsigned long index = start >> PAGE_SHIFT;
212 unsigned long end_index = end >> PAGE_SHIFT;
213 struct page *page;
214
215 while (index <= end_index) {
216 page = find_get_page(inode->i_mapping, index);
217 BUG_ON(!page); /* Pages should be in the extent_io_tree */
218 clear_page_dirty_for_io(page);
219 put_page(page);
220 index++;
221 }
222}
223
224void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
225{
226 struct address_space *mapping = inode->i_mapping;
227 unsigned long index = start >> PAGE_SHIFT;
228 unsigned long end_index = end >> PAGE_SHIFT;
229 struct folio *folio;
230
231 while (index <= end_index) {
232 folio = filemap_get_folio(mapping, index);
233 filemap_dirty_folio(mapping, folio);
234 folio_account_redirty(folio);
235 index += folio_nr_pages(folio);
236 folio_put(folio);
237 }
238}
239
240/*
241 * Process one page for __process_pages_contig().
242 *
243 * Return >0 if we hit @page == @locked_page.
244 * Return 0 if we updated the page status.
245 * Return -EGAIN if the we need to try again.
246 * (For PAGE_LOCK case but got dirty page or page not belong to mapping)
247 */
248static int process_one_page(struct btrfs_fs_info *fs_info,
249 struct address_space *mapping,
250 struct page *page, struct page *locked_page,
251 unsigned long page_ops, u64 start, u64 end)
252{
253 u32 len;
254
255 ASSERT(end + 1 - start != 0 && end + 1 - start < U32_MAX);
256 len = end + 1 - start;
257
258 if (page_ops & PAGE_SET_ORDERED)
259 btrfs_page_clamp_set_ordered(fs_info, page, start, len);
260 if (page_ops & PAGE_SET_ERROR)
261 btrfs_page_clamp_set_error(fs_info, page, start, len);
262 if (page_ops & PAGE_START_WRITEBACK) {
263 btrfs_page_clamp_clear_dirty(fs_info, page, start, len);
264 btrfs_page_clamp_set_writeback(fs_info, page, start, len);
265 }
266 if (page_ops & PAGE_END_WRITEBACK)
267 btrfs_page_clamp_clear_writeback(fs_info, page, start, len);
268
269 if (page == locked_page)
270 return 1;
271
272 if (page_ops & PAGE_LOCK) {
273 int ret;
274
275 ret = btrfs_page_start_writer_lock(fs_info, page, start, len);
276 if (ret)
277 return ret;
278 if (!PageDirty(page) || page->mapping != mapping) {
279 btrfs_page_end_writer_lock(fs_info, page, start, len);
280 return -EAGAIN;
281 }
282 }
283 if (page_ops & PAGE_UNLOCK)
284 btrfs_page_end_writer_lock(fs_info, page, start, len);
285 return 0;
286}
287
288static int __process_pages_contig(struct address_space *mapping,
289 struct page *locked_page,
290 u64 start, u64 end, unsigned long page_ops,
291 u64 *processed_end)
292{
293 struct btrfs_fs_info *fs_info = btrfs_sb(mapping->host->i_sb);
294 pgoff_t start_index = start >> PAGE_SHIFT;
295 pgoff_t end_index = end >> PAGE_SHIFT;
296 pgoff_t index = start_index;
297 unsigned long pages_processed = 0;
298 struct folio_batch fbatch;
299 int err = 0;
300 int i;
301
302 if (page_ops & PAGE_LOCK) {
303 ASSERT(page_ops == PAGE_LOCK);
304 ASSERT(processed_end && *processed_end == start);
305 }
306
307 if ((page_ops & PAGE_SET_ERROR) && start_index <= end_index)
308 mapping_set_error(mapping, -EIO);
309
310 folio_batch_init(&fbatch);
311 while (index <= end_index) {
312 int found_folios;
313
314 found_folios = filemap_get_folios_contig(mapping, &index,
315 end_index, &fbatch);
316
317 if (found_folios == 0) {
318 /*
319 * Only if we're going to lock these pages, we can find
320 * nothing at @index.
321 */
322 ASSERT(page_ops & PAGE_LOCK);
323 err = -EAGAIN;
324 goto out;
325 }
326
327 for (i = 0; i < found_folios; i++) {
328 int process_ret;
329 struct folio *folio = fbatch.folios[i];
330 process_ret = process_one_page(fs_info, mapping,
331 &folio->page, locked_page, page_ops,
332 start, end);
333 if (process_ret < 0) {
334 err = -EAGAIN;
335 folio_batch_release(&fbatch);
336 goto out;
337 }
338 pages_processed += folio_nr_pages(folio);
339 }
340 folio_batch_release(&fbatch);
341 cond_resched();
342 }
343out:
344 if (err && processed_end) {
345 /*
346 * Update @processed_end. I know this is awful since it has
347 * two different return value patterns (inclusive vs exclusive).
348 *
349 * But the exclusive pattern is necessary if @start is 0, or we
350 * underflow and check against processed_end won't work as
351 * expected.
352 */
353 if (pages_processed)
354 *processed_end = min(end,
355 ((u64)(start_index + pages_processed) << PAGE_SHIFT) - 1);
356 else
357 *processed_end = start;
358 }
359 return err;
360}
361
362static noinline void __unlock_for_delalloc(struct inode *inode,
363 struct page *locked_page,
364 u64 start, u64 end)
365{
366 unsigned long index = start >> PAGE_SHIFT;
367 unsigned long end_index = end >> PAGE_SHIFT;
368
369 ASSERT(locked_page);
370 if (index == locked_page->index && end_index == index)
371 return;
372
373 __process_pages_contig(inode->i_mapping, locked_page, start, end,
374 PAGE_UNLOCK, NULL);
375}
376
377static noinline int lock_delalloc_pages(struct inode *inode,
378 struct page *locked_page,
379 u64 delalloc_start,
380 u64 delalloc_end)
381{
382 unsigned long index = delalloc_start >> PAGE_SHIFT;
383 unsigned long end_index = delalloc_end >> PAGE_SHIFT;
384 u64 processed_end = delalloc_start;
385 int ret;
386
387 ASSERT(locked_page);
388 if (index == locked_page->index && index == end_index)
389 return 0;
390
391 ret = __process_pages_contig(inode->i_mapping, locked_page, delalloc_start,
392 delalloc_end, PAGE_LOCK, &processed_end);
393 if (ret == -EAGAIN && processed_end > delalloc_start)
394 __unlock_for_delalloc(inode, locked_page, delalloc_start,
395 processed_end);
396 return ret;
397}
398
399/*
400 * Find and lock a contiguous range of bytes in the file marked as delalloc, no
401 * more than @max_bytes.
402 *
403 * @start: The original start bytenr to search.
404 * Will store the extent range start bytenr.
405 * @end: The original end bytenr of the search range
406 * Will store the extent range end bytenr.
407 *
408 * Return true if we find a delalloc range which starts inside the original
409 * range, and @start/@end will store the delalloc range start/end.
410 *
411 * Return false if we can't find any delalloc range which starts inside the
412 * original range, and @start/@end will be the non-delalloc range start/end.
413 */
414EXPORT_FOR_TESTS
415noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
416 struct page *locked_page, u64 *start,
417 u64 *end)
418{
419 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
420 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
421 const u64 orig_start = *start;
422 const u64 orig_end = *end;
423 /* The sanity tests may not set a valid fs_info. */
424 u64 max_bytes = fs_info ? fs_info->max_extent_size : BTRFS_MAX_EXTENT_SIZE;
425 u64 delalloc_start;
426 u64 delalloc_end;
427 bool found;
428 struct extent_state *cached_state = NULL;
429 int ret;
430 int loops = 0;
431
432 /* Caller should pass a valid @end to indicate the search range end */
433 ASSERT(orig_end > orig_start);
434
435 /* The range should at least cover part of the page */
436 ASSERT(!(orig_start >= page_offset(locked_page) + PAGE_SIZE ||
437 orig_end <= page_offset(locked_page)));
438again:
439 /* step one, find a bunch of delalloc bytes starting at start */
440 delalloc_start = *start;
441 delalloc_end = 0;
442 found = btrfs_find_delalloc_range(tree, &delalloc_start, &delalloc_end,
443 max_bytes, &cached_state);
444 if (!found || delalloc_end <= *start || delalloc_start > orig_end) {
445 *start = delalloc_start;
446
447 /* @delalloc_end can be -1, never go beyond @orig_end */
448 *end = min(delalloc_end, orig_end);
449 free_extent_state(cached_state);
450 return false;
451 }
452
453 /*
454 * start comes from the offset of locked_page. We have to lock
455 * pages in order, so we can't process delalloc bytes before
456 * locked_page
457 */
458 if (delalloc_start < *start)
459 delalloc_start = *start;
460
461 /*
462 * make sure to limit the number of pages we try to lock down
463 */
464 if (delalloc_end + 1 - delalloc_start > max_bytes)
465 delalloc_end = delalloc_start + max_bytes - 1;
466
467 /* step two, lock all the pages after the page that has start */
468 ret = lock_delalloc_pages(inode, locked_page,
469 delalloc_start, delalloc_end);
470 ASSERT(!ret || ret == -EAGAIN);
471 if (ret == -EAGAIN) {
472 /* some of the pages are gone, lets avoid looping by
473 * shortening the size of the delalloc range we're searching
474 */
475 free_extent_state(cached_state);
476 cached_state = NULL;
477 if (!loops) {
478 max_bytes = PAGE_SIZE;
479 loops = 1;
480 goto again;
481 } else {
482 found = false;
483 goto out_failed;
484 }
485 }
486
487 /* step three, lock the state bits for the whole range */
488 lock_extent(tree, delalloc_start, delalloc_end, &cached_state);
489
490 /* then test to make sure it is all still delalloc */
491 ret = test_range_bit(tree, delalloc_start, delalloc_end,
492 EXTENT_DELALLOC, 1, cached_state);
493 if (!ret) {
494 unlock_extent(tree, delalloc_start, delalloc_end,
495 &cached_state);
496 __unlock_for_delalloc(inode, locked_page,
497 delalloc_start, delalloc_end);
498 cond_resched();
499 goto again;
500 }
501 free_extent_state(cached_state);
502 *start = delalloc_start;
503 *end = delalloc_end;
504out_failed:
505 return found;
506}
507
508void extent_clear_unlock_delalloc(struct btrfs_inode *inode, u64 start, u64 end,
509 struct page *locked_page,
510 u32 clear_bits, unsigned long page_ops)
511{
512 clear_extent_bit(&inode->io_tree, start, end, clear_bits, NULL);
513
514 __process_pages_contig(inode->vfs_inode.i_mapping, locked_page,
515 start, end, page_ops, NULL);
516}
517
518static int insert_failrec(struct btrfs_inode *inode,
519 struct io_failure_record *failrec)
520{
521 struct rb_node *exist;
522
523 spin_lock(&inode->io_failure_lock);
524 exist = rb_simple_insert(&inode->io_failure_tree, failrec->bytenr,
525 &failrec->rb_node);
526 spin_unlock(&inode->io_failure_lock);
527
528 return (exist == NULL) ? 0 : -EEXIST;
529}
530
531static struct io_failure_record *get_failrec(struct btrfs_inode *inode, u64 start)
532{
533 struct rb_node *node;
534 struct io_failure_record *failrec = ERR_PTR(-ENOENT);
535
536 spin_lock(&inode->io_failure_lock);
537 node = rb_simple_search(&inode->io_failure_tree, start);
538 if (node)
539 failrec = rb_entry(node, struct io_failure_record, rb_node);
540 spin_unlock(&inode->io_failure_lock);
541 return failrec;
542}
543
544static void free_io_failure(struct btrfs_inode *inode,
545 struct io_failure_record *rec)
546{
547 spin_lock(&inode->io_failure_lock);
548 rb_erase(&rec->rb_node, &inode->io_failure_tree);
549 spin_unlock(&inode->io_failure_lock);
550
551 kfree(rec);
552}
553
554static int next_mirror(const struct io_failure_record *failrec, int cur_mirror)
555{
556 if (cur_mirror == failrec->num_copies)
557 return cur_mirror + 1 - failrec->num_copies;
558 return cur_mirror + 1;
559}
560
561static int prev_mirror(const struct io_failure_record *failrec, int cur_mirror)
562{
563 if (cur_mirror == 1)
564 return failrec->num_copies;
565 return cur_mirror - 1;
566}
567
568/*
569 * each time an IO finishes, we do a fast check in the IO failure tree
570 * to see if we need to process or clean up an io_failure_record
571 */
572int btrfs_clean_io_failure(struct btrfs_inode *inode, u64 start,
573 struct page *page, unsigned int pg_offset)
574{
575 struct btrfs_fs_info *fs_info = inode->root->fs_info;
576 struct extent_io_tree *io_tree = &inode->io_tree;
577 u64 ino = btrfs_ino(inode);
578 u64 locked_start, locked_end;
579 struct io_failure_record *failrec;
580 int mirror;
581 int ret;
582
583 failrec = get_failrec(inode, start);
584 if (IS_ERR(failrec))
585 return 0;
586
587 BUG_ON(!failrec->this_mirror);
588
589 if (sb_rdonly(fs_info->sb))
590 goto out;
591
592 ret = find_first_extent_bit(io_tree, failrec->bytenr, &locked_start,
593 &locked_end, EXTENT_LOCKED, NULL);
594 if (ret || locked_start > failrec->bytenr ||
595 locked_end < failrec->bytenr + failrec->len - 1)
596 goto out;
597
598 mirror = failrec->this_mirror;
599 do {
600 mirror = prev_mirror(failrec, mirror);
601 btrfs_repair_io_failure(fs_info, ino, start, failrec->len,
602 failrec->logical, page, pg_offset, mirror);
603 } while (mirror != failrec->failed_mirror);
604
605out:
606 free_io_failure(inode, failrec);
607 return 0;
608}
609
610/*
611 * Can be called when
612 * - hold extent lock
613 * - under ordered extent
614 * - the inode is freeing
615 */
616void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start, u64 end)
617{
618 struct io_failure_record *failrec;
619 struct rb_node *node, *next;
620
621 if (RB_EMPTY_ROOT(&inode->io_failure_tree))
622 return;
623
624 spin_lock(&inode->io_failure_lock);
625 node = rb_simple_search_first(&inode->io_failure_tree, start);
626 while (node) {
627 failrec = rb_entry(node, struct io_failure_record, rb_node);
628 if (failrec->bytenr > end)
629 break;
630
631 next = rb_next(node);
632 rb_erase(&failrec->rb_node, &inode->io_failure_tree);
633 kfree(failrec);
634
635 node = next;
636 }
637 spin_unlock(&inode->io_failure_lock);
638}
639
640static struct io_failure_record *btrfs_get_io_failure_record(struct inode *inode,
641 struct btrfs_bio *bbio,
642 unsigned int bio_offset)
643{
644 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
645 u64 start = bbio->file_offset + bio_offset;
646 struct io_failure_record *failrec;
647 const u32 sectorsize = fs_info->sectorsize;
648 int ret;
649
650 failrec = get_failrec(BTRFS_I(inode), start);
651 if (!IS_ERR(failrec)) {
652 btrfs_debug(fs_info,
653 "Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu",
654 failrec->logical, failrec->bytenr, failrec->len);
655 /*
656 * when data can be on disk more than twice, add to failrec here
657 * (e.g. with a list for failed_mirror) to make
658 * clean_io_failure() clean all those errors at once.
659 */
660 ASSERT(failrec->this_mirror == bbio->mirror_num);
661 ASSERT(failrec->len == fs_info->sectorsize);
662 return failrec;
663 }
664
665 failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
666 if (!failrec)
667 return ERR_PTR(-ENOMEM);
668
669 RB_CLEAR_NODE(&failrec->rb_node);
670 failrec->bytenr = start;
671 failrec->len = sectorsize;
672 failrec->failed_mirror = bbio->mirror_num;
673 failrec->this_mirror = bbio->mirror_num;
674 failrec->logical = (bbio->iter.bi_sector << SECTOR_SHIFT) + bio_offset;
675
676 btrfs_debug(fs_info,
677 "new io failure record logical %llu start %llu",
678 failrec->logical, start);
679
680 failrec->num_copies = btrfs_num_copies(fs_info, failrec->logical, sectorsize);
681 if (failrec->num_copies == 1) {
682 /*
683 * We only have a single copy of the data, so don't bother with
684 * all the retry and error correction code that follows. No
685 * matter what the error is, it is very likely to persist.
686 */
687 btrfs_debug(fs_info,
688 "cannot repair logical %llu num_copies %d",
689 failrec->logical, failrec->num_copies);
690 kfree(failrec);
691 return ERR_PTR(-EIO);
692 }
693
694 /* Set the bits in the private failure tree */
695 ret = insert_failrec(BTRFS_I(inode), failrec);
696 if (ret) {
697 kfree(failrec);
698 return ERR_PTR(ret);
699 }
700
701 return failrec;
702}
703
704int btrfs_repair_one_sector(struct btrfs_inode *inode, struct btrfs_bio *failed_bbio,
705 u32 bio_offset, struct page *page, unsigned int pgoff,
706 bool submit_buffered)
707{
708 u64 start = failed_bbio->file_offset + bio_offset;
709 struct io_failure_record *failrec;
710 struct btrfs_fs_info *fs_info = inode->root->fs_info;
711 struct bio *failed_bio = &failed_bbio->bio;
712 const int icsum = bio_offset >> fs_info->sectorsize_bits;
713 struct bio *repair_bio;
714 struct btrfs_bio *repair_bbio;
715
716 btrfs_debug(fs_info,
717 "repair read error: read error at %llu", start);
718
719 BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
720
721 failrec = btrfs_get_io_failure_record(&inode->vfs_inode, failed_bbio, bio_offset);
722 if (IS_ERR(failrec))
723 return PTR_ERR(failrec);
724
725 /*
726 * There are two premises:
727 * a) deliver good data to the caller
728 * b) correct the bad sectors on disk
729 *
730 * Since we're only doing repair for one sector, we only need to get
731 * a good copy of the failed sector and if we succeed, we have setup
732 * everything for btrfs_repair_io_failure to do the rest for us.
733 */
734 failrec->this_mirror = next_mirror(failrec, failrec->this_mirror);
735 if (failrec->this_mirror == failrec->failed_mirror) {
736 btrfs_debug(fs_info,
737 "failed to repair num_copies %d this_mirror %d failed_mirror %d",
738 failrec->num_copies, failrec->this_mirror, failrec->failed_mirror);
739 free_io_failure(inode, failrec);
740 return -EIO;
741 }
742
743 repair_bio = btrfs_bio_alloc(1, REQ_OP_READ, failed_bbio->end_io,
744 failed_bbio->private);
745 repair_bbio = btrfs_bio(repair_bio);
746 repair_bbio->file_offset = start;
747 repair_bio->bi_iter.bi_sector = failrec->logical >> 9;
748
749 if (failed_bbio->csum) {
750 const u32 csum_size = fs_info->csum_size;
751
752 repair_bbio->csum = repair_bbio->csum_inline;
753 memcpy(repair_bbio->csum,
754 failed_bbio->csum + csum_size * icsum, csum_size);
755 }
756
757 bio_add_page(repair_bio, page, failrec->len, pgoff);
758 repair_bbio->iter = repair_bio->bi_iter;
759
760 btrfs_debug(fs_info,
761 "repair read error: submitting new read to mirror %d",
762 failrec->this_mirror);
763
764 /*
765 * At this point we have a bio, so any errors from bio submission will
766 * be handled by the endio on the repair_bio, so we can't return an
767 * error here.
768 */
769 if (submit_buffered)
770 btrfs_submit_data_read_bio(inode, repair_bio,
771 failrec->this_mirror, 0);
772 else
773 btrfs_submit_dio_repair_bio(inode, repair_bio, failrec->this_mirror);
774
775 return BLK_STS_OK;
776}
777
778static void end_page_read(struct page *page, bool uptodate, u64 start, u32 len)
779{
780 struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
781
782 ASSERT(page_offset(page) <= start &&
783 start + len <= page_offset(page) + PAGE_SIZE);
784
785 if (uptodate) {
786 if (fsverity_active(page->mapping->host) &&
787 !PageError(page) &&
788 !PageUptodate(page) &&
789 start < i_size_read(page->mapping->host) &&
790 !fsverity_verify_page(page)) {
791 btrfs_page_set_error(fs_info, page, start, len);
792 } else {
793 btrfs_page_set_uptodate(fs_info, page, start, len);
794 }
795 } else {
796 btrfs_page_clear_uptodate(fs_info, page, start, len);
797 btrfs_page_set_error(fs_info, page, start, len);
798 }
799
800 if (!btrfs_is_subpage(fs_info, page))
801 unlock_page(page);
802 else
803 btrfs_subpage_end_reader(fs_info, page, start, len);
804}
805
806static void end_sector_io(struct page *page, u64 offset, bool uptodate)
807{
808 struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
809 const u32 sectorsize = inode->root->fs_info->sectorsize;
810
811 end_page_read(page, uptodate, offset, sectorsize);
812 unlock_extent(&inode->io_tree, offset, offset + sectorsize - 1, NULL);
813}
814
815static void submit_data_read_repair(struct inode *inode,
816 struct btrfs_bio *failed_bbio,
817 u32 bio_offset, const struct bio_vec *bvec,
818 unsigned int error_bitmap)
819{
820 const unsigned int pgoff = bvec->bv_offset;
821 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
822 struct page *page = bvec->bv_page;
823 const u64 start = page_offset(bvec->bv_page) + bvec->bv_offset;
824 const u64 end = start + bvec->bv_len - 1;
825 const u32 sectorsize = fs_info->sectorsize;
826 const int nr_bits = (end + 1 - start) >> fs_info->sectorsize_bits;
827 int i;
828
829 BUG_ON(bio_op(&failed_bbio->bio) == REQ_OP_WRITE);
830
831 /* This repair is only for data */
832 ASSERT(is_data_inode(inode));
833
834 /* We're here because we had some read errors or csum mismatch */
835 ASSERT(error_bitmap);
836
837 /*
838 * We only get called on buffered IO, thus page must be mapped and bio
839 * must not be cloned.
840 */
841 ASSERT(page->mapping && !bio_flagged(&failed_bbio->bio, BIO_CLONED));
842
843 /* Iterate through all the sectors in the range */
844 for (i = 0; i < nr_bits; i++) {
845 const unsigned int offset = i * sectorsize;
846 bool uptodate = false;
847 int ret;
848
849 if (!(error_bitmap & (1U << i))) {
850 /*
851 * This sector has no error, just end the page read
852 * and unlock the range.
853 */
854 uptodate = true;
855 goto next;
856 }
857
858 ret = btrfs_repair_one_sector(BTRFS_I(inode), failed_bbio,
859 bio_offset + offset, page, pgoff + offset,
860 true);
861 if (!ret) {
862 /*
863 * We have submitted the read repair, the page release
864 * will be handled by the endio function of the
865 * submitted repair bio.
866 * Thus we don't need to do any thing here.
867 */
868 continue;
869 }
870 /*
871 * Continue on failed repair, otherwise the remaining sectors
872 * will not be properly unlocked.
873 */
874next:
875 end_sector_io(page, start + offset, uptodate);
876 }
877}
878
879/* lots and lots of room for performance fixes in the end_bio funcs */
880
881void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
882{
883 struct btrfs_inode *inode;
884 const bool uptodate = (err == 0);
885 int ret = 0;
886
887 ASSERT(page && page->mapping);
888 inode = BTRFS_I(page->mapping->host);
889 btrfs_writepage_endio_finish_ordered(inode, page, start, end, uptodate);
890
891 if (!uptodate) {
892 const struct btrfs_fs_info *fs_info = inode->root->fs_info;
893 u32 len;
894
895 ASSERT(end + 1 - start <= U32_MAX);
896 len = end + 1 - start;
897
898 btrfs_page_clear_uptodate(fs_info, page, start, len);
899 btrfs_page_set_error(fs_info, page, start, len);
900 ret = err < 0 ? err : -EIO;
901 mapping_set_error(page->mapping, ret);
902 }
903}
904
905/*
906 * after a writepage IO is done, we need to:
907 * clear the uptodate bits on error
908 * clear the writeback bits in the extent tree for this IO
909 * end_page_writeback if the page has no more pending IO
910 *
911 * Scheduling is not allowed, so the extent state tree is expected
912 * to have one and only one object corresponding to this IO.
913 */
914static void end_bio_extent_writepage(struct btrfs_bio *bbio)
915{
916 struct bio *bio = &bbio->bio;
917 int error = blk_status_to_errno(bio->bi_status);
918 struct bio_vec *bvec;
919 u64 start;
920 u64 end;
921 struct bvec_iter_all iter_all;
922 bool first_bvec = true;
923
924 ASSERT(!bio_flagged(bio, BIO_CLONED));
925 bio_for_each_segment_all(bvec, bio, iter_all) {
926 struct page *page = bvec->bv_page;
927 struct inode *inode = page->mapping->host;
928 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
929 const u32 sectorsize = fs_info->sectorsize;
930
931 /* Our read/write should always be sector aligned. */
932 if (!IS_ALIGNED(bvec->bv_offset, sectorsize))
933 btrfs_err(fs_info,
934 "partial page write in btrfs with offset %u and length %u",
935 bvec->bv_offset, bvec->bv_len);
936 else if (!IS_ALIGNED(bvec->bv_len, sectorsize))
937 btrfs_info(fs_info,
938 "incomplete page write with offset %u and length %u",
939 bvec->bv_offset, bvec->bv_len);
940
941 start = page_offset(page) + bvec->bv_offset;
942 end = start + bvec->bv_len - 1;
943
944 if (first_bvec) {
945 btrfs_record_physical_zoned(inode, start, bio);
946 first_bvec = false;
947 }
948
949 end_extent_writepage(page, error, start, end);
950
951 btrfs_page_clear_writeback(fs_info, page, start, bvec->bv_len);
952 }
953
954 bio_put(bio);
955}
956
957/*
958 * Record previously processed extent range
959 *
960 * For endio_readpage_release_extent() to handle a full extent range, reducing
961 * the extent io operations.
962 */
963struct processed_extent {
964 struct btrfs_inode *inode;
965 /* Start of the range in @inode */
966 u64 start;
967 /* End of the range in @inode */
968 u64 end;
969 bool uptodate;
970};
971
972/*
973 * Try to release processed extent range
974 *
975 * May not release the extent range right now if the current range is
976 * contiguous to processed extent.
977 *
978 * Will release processed extent when any of @inode, @uptodate, the range is
979 * no longer contiguous to the processed range.
980 *
981 * Passing @inode == NULL will force processed extent to be released.
982 */
983static void endio_readpage_release_extent(struct processed_extent *processed,
984 struct btrfs_inode *inode, u64 start, u64 end,
985 bool uptodate)
986{
987 struct extent_state *cached = NULL;
988 struct extent_io_tree *tree;
989
990 /* The first extent, initialize @processed */
991 if (!processed->inode)
992 goto update;
993
994 /*
995 * Contiguous to processed extent, just uptodate the end.
996 *
997 * Several things to notice:
998 *
999 * - bio can be merged as long as on-disk bytenr is contiguous
1000 * This means we can have page belonging to other inodes, thus need to
1001 * check if the inode still matches.
1002 * - bvec can contain range beyond current page for multi-page bvec
1003 * Thus we need to do processed->end + 1 >= start check
1004 */
1005 if (processed->inode == inode && processed->uptodate == uptodate &&
1006 processed->end + 1 >= start && end >= processed->end) {
1007 processed->end = end;
1008 return;
1009 }
1010
1011 tree = &processed->inode->io_tree;
1012 /*
1013 * Now we don't have range contiguous to the processed range, release
1014 * the processed range now.
1015 */
1016 unlock_extent(tree, processed->start, processed->end, &cached);
1017
1018update:
1019 /* Update processed to current range */
1020 processed->inode = inode;
1021 processed->start = start;
1022 processed->end = end;
1023 processed->uptodate = uptodate;
1024}
1025
1026static void begin_page_read(struct btrfs_fs_info *fs_info, struct page *page)
1027{
1028 ASSERT(PageLocked(page));
1029 if (!btrfs_is_subpage(fs_info, page))
1030 return;
1031
1032 ASSERT(PagePrivate(page));
1033 btrfs_subpage_start_reader(fs_info, page, page_offset(page), PAGE_SIZE);
1034}
1035
1036/*
1037 * Find extent buffer for a givne bytenr.
1038 *
1039 * This is for end_bio_extent_readpage(), thus we can't do any unsafe locking
1040 * in endio context.
1041 */
1042static struct extent_buffer *find_extent_buffer_readpage(
1043 struct btrfs_fs_info *fs_info, struct page *page, u64 bytenr)
1044{
1045 struct extent_buffer *eb;
1046
1047 /*
1048 * For regular sectorsize, we can use page->private to grab extent
1049 * buffer
1050 */
1051 if (fs_info->nodesize >= PAGE_SIZE) {
1052 ASSERT(PagePrivate(page) && page->private);
1053 return (struct extent_buffer *)page->private;
1054 }
1055
1056 /* For subpage case, we need to lookup buffer radix tree */
1057 rcu_read_lock();
1058 eb = radix_tree_lookup(&fs_info->buffer_radix,
1059 bytenr >> fs_info->sectorsize_bits);
1060 rcu_read_unlock();
1061 ASSERT(eb);
1062 return eb;
1063}
1064
1065/*
1066 * after a readpage IO is done, we need to:
1067 * clear the uptodate bits on error
1068 * set the uptodate bits if things worked
1069 * set the page up to date if all extents in the tree are uptodate
1070 * clear the lock bit in the extent tree
1071 * unlock the page if there are no other extents locked for it
1072 *
1073 * Scheduling is not allowed, so the extent state tree is expected
1074 * to have one and only one object corresponding to this IO.
1075 */
1076static void end_bio_extent_readpage(struct btrfs_bio *bbio)
1077{
1078 struct bio *bio = &bbio->bio;
1079 struct bio_vec *bvec;
1080 struct processed_extent processed = { 0 };
1081 /*
1082 * The offset to the beginning of a bio, since one bio can never be
1083 * larger than UINT_MAX, u32 here is enough.
1084 */
1085 u32 bio_offset = 0;
1086 int mirror;
1087 struct bvec_iter_all iter_all;
1088
1089 ASSERT(!bio_flagged(bio, BIO_CLONED));
1090 bio_for_each_segment_all(bvec, bio, iter_all) {
1091 bool uptodate = !bio->bi_status;
1092 struct page *page = bvec->bv_page;
1093 struct inode *inode = page->mapping->host;
1094 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1095 const u32 sectorsize = fs_info->sectorsize;
1096 unsigned int error_bitmap = (unsigned int)-1;
1097 bool repair = false;
1098 u64 start;
1099 u64 end;
1100 u32 len;
1101
1102 btrfs_debug(fs_info,
1103 "end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
1104 bio->bi_iter.bi_sector, bio->bi_status,
1105 bbio->mirror_num);
1106
1107 /*
1108 * We always issue full-sector reads, but if some block in a
1109 * page fails to read, blk_update_request() will advance
1110 * bv_offset and adjust bv_len to compensate. Print a warning
1111 * for unaligned offsets, and an error if they don't add up to
1112 * a full sector.
1113 */
1114 if (!IS_ALIGNED(bvec->bv_offset, sectorsize))
1115 btrfs_err(fs_info,
1116 "partial page read in btrfs with offset %u and length %u",
1117 bvec->bv_offset, bvec->bv_len);
1118 else if (!IS_ALIGNED(bvec->bv_offset + bvec->bv_len,
1119 sectorsize))
1120 btrfs_info(fs_info,
1121 "incomplete page read with offset %u and length %u",
1122 bvec->bv_offset, bvec->bv_len);
1123
1124 start = page_offset(page) + bvec->bv_offset;
1125 end = start + bvec->bv_len - 1;
1126 len = bvec->bv_len;
1127
1128 mirror = bbio->mirror_num;
1129 if (likely(uptodate)) {
1130 if (is_data_inode(inode)) {
1131 error_bitmap = btrfs_verify_data_csum(bbio,
1132 bio_offset, page, start, end);
1133 if (error_bitmap)
1134 uptodate = false;
1135 } else {
1136 if (btrfs_validate_metadata_buffer(bbio,
1137 page, start, end, mirror))
1138 uptodate = false;
1139 }
1140 }
1141
1142 if (likely(uptodate)) {
1143 loff_t i_size = i_size_read(inode);
1144 pgoff_t end_index = i_size >> PAGE_SHIFT;
1145
1146 btrfs_clean_io_failure(BTRFS_I(inode), start, page, 0);
1147
1148 /*
1149 * Zero out the remaining part if this range straddles
1150 * i_size.
1151 *
1152 * Here we should only zero the range inside the bvec,
1153 * not touch anything else.
1154 *
1155 * NOTE: i_size is exclusive while end is inclusive.
1156 */
1157 if (page->index == end_index && i_size <= end) {
1158 u32 zero_start = max(offset_in_page(i_size),
1159 offset_in_page(start));
1160
1161 zero_user_segment(page, zero_start,
1162 offset_in_page(end) + 1);
1163 }
1164 } else if (is_data_inode(inode)) {
1165 /*
1166 * Only try to repair bios that actually made it to a
1167 * device. If the bio failed to be submitted mirror
1168 * is 0 and we need to fail it without retrying.
1169 *
1170 * This also includes the high level bios for compressed
1171 * extents - these never make it to a device and repair
1172 * is already handled on the lower compressed bio.
1173 */
1174 if (mirror > 0)
1175 repair = true;
1176 } else {
1177 struct extent_buffer *eb;
1178
1179 eb = find_extent_buffer_readpage(fs_info, page, start);
1180 set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
1181 eb->read_mirror = mirror;
1182 atomic_dec(&eb->io_pages);
1183 }
1184
1185 if (repair) {
1186 /*
1187 * submit_data_read_repair() will handle all the good
1188 * and bad sectors, we just continue to the next bvec.
1189 */
1190 submit_data_read_repair(inode, bbio, bio_offset, bvec,
1191 error_bitmap);
1192 } else {
1193 /* Update page status and unlock */
1194 end_page_read(page, uptodate, start, len);
1195 endio_readpage_release_extent(&processed, BTRFS_I(inode),
1196 start, end, PageUptodate(page));
1197 }
1198
1199 ASSERT(bio_offset + len > bio_offset);
1200 bio_offset += len;
1201
1202 }
1203 /* Release the last extent */
1204 endio_readpage_release_extent(&processed, NULL, 0, 0, false);
1205 btrfs_bio_free_csum(bbio);
1206 bio_put(bio);
1207}
1208
1209/*
1210 * Populate every free slot in a provided array with pages.
1211 *
1212 * @nr_pages: number of pages to allocate
1213 * @page_array: the array to fill with pages; any existing non-null entries in
1214 * the array will be skipped
1215 *
1216 * Return: 0 if all pages were able to be allocated;
1217 * -ENOMEM otherwise, and the caller is responsible for freeing all
1218 * non-null page pointers in the array.
1219 */
1220int btrfs_alloc_page_array(unsigned int nr_pages, struct page **page_array)
1221{
1222 unsigned int allocated;
1223
1224 for (allocated = 0; allocated < nr_pages;) {
1225 unsigned int last = allocated;
1226
1227 allocated = alloc_pages_bulk_array(GFP_NOFS, nr_pages, page_array);
1228
1229 if (allocated == nr_pages)
1230 return 0;
1231
1232 /*
1233 * During this iteration, no page could be allocated, even
1234 * though alloc_pages_bulk_array() falls back to alloc_page()
1235 * if it could not bulk-allocate. So we must be out of memory.
1236 */
1237 if (allocated == last)
1238 return -ENOMEM;
1239
1240 memalloc_retry_wait(GFP_NOFS);
1241 }
1242 return 0;
1243}
1244
1245/*
1246 * Attempt to add a page to bio.
1247 *
1248 * @bio_ctrl: record both the bio, and its bio_flags
1249 * @page: page to add to the bio
1250 * @disk_bytenr: offset of the new bio or to check whether we are adding
1251 * a contiguous page to the previous one
1252 * @size: portion of page that we want to write
1253 * @pg_offset: starting offset in the page
1254 * @compress_type: compression type of the current bio to see if we can merge them
1255 *
1256 * Attempt to add a page to bio considering stripe alignment etc.
1257 *
1258 * Return >= 0 for the number of bytes added to the bio.
1259 * Can return 0 if the current bio is already at stripe/zone boundary.
1260 * Return <0 for error.
1261 */
1262static int btrfs_bio_add_page(struct btrfs_bio_ctrl *bio_ctrl,
1263 struct page *page,
1264 u64 disk_bytenr, unsigned int size,
1265 unsigned int pg_offset,
1266 enum btrfs_compression_type compress_type)
1267{
1268 struct bio *bio = bio_ctrl->bio;
1269 u32 bio_size = bio->bi_iter.bi_size;
1270 u32 real_size;
1271 const sector_t sector = disk_bytenr >> SECTOR_SHIFT;
1272 bool contig = false;
1273 int ret;
1274
1275 ASSERT(bio);
1276 /* The limit should be calculated when bio_ctrl->bio is allocated */
1277 ASSERT(bio_ctrl->len_to_oe_boundary && bio_ctrl->len_to_stripe_boundary);
1278 if (bio_ctrl->compress_type != compress_type)
1279 return 0;
1280
1281
1282 if (bio->bi_iter.bi_size == 0) {
1283 /* We can always add a page into an empty bio. */
1284 contig = true;
1285 } else if (bio_ctrl->compress_type == BTRFS_COMPRESS_NONE) {
1286 struct bio_vec *bvec = bio_last_bvec_all(bio);
1287
1288 /*
1289 * The contig check requires the following conditions to be met:
1290 * 1) The pages are belonging to the same inode
1291 * This is implied by the call chain.
1292 *
1293 * 2) The range has adjacent logical bytenr
1294 *
1295 * 3) The range has adjacent file offset
1296 * This is required for the usage of btrfs_bio->file_offset.
1297 */
1298 if (bio_end_sector(bio) == sector &&
1299 page_offset(bvec->bv_page) + bvec->bv_offset +
1300 bvec->bv_len == page_offset(page) + pg_offset)
1301 contig = true;
1302 } else {
1303 /*
1304 * For compression, all IO should have its logical bytenr
1305 * set to the starting bytenr of the compressed extent.
1306 */
1307 contig = bio->bi_iter.bi_sector == sector;
1308 }
1309
1310 if (!contig)
1311 return 0;
1312
1313 real_size = min(bio_ctrl->len_to_oe_boundary,
1314 bio_ctrl->len_to_stripe_boundary) - bio_size;
1315 real_size = min(real_size, size);
1316
1317 /*
1318 * If real_size is 0, never call bio_add_*_page(), as even size is 0,
1319 * bio will still execute its endio function on the page!
1320 */
1321 if (real_size == 0)
1322 return 0;
1323
1324 if (bio_op(bio) == REQ_OP_ZONE_APPEND)
1325 ret = bio_add_zone_append_page(bio, page, real_size, pg_offset);
1326 else
1327 ret = bio_add_page(bio, page, real_size, pg_offset);
1328
1329 return ret;
1330}
1331
1332static int calc_bio_boundaries(struct btrfs_bio_ctrl *bio_ctrl,
1333 struct btrfs_inode *inode, u64 file_offset)
1334{
1335 struct btrfs_fs_info *fs_info = inode->root->fs_info;
1336 struct btrfs_io_geometry geom;
1337 struct btrfs_ordered_extent *ordered;
1338 struct extent_map *em;
1339 u64 logical = (bio_ctrl->bio->bi_iter.bi_sector << SECTOR_SHIFT);
1340 int ret;
1341
1342 /*
1343 * Pages for compressed extent are never submitted to disk directly,
1344 * thus it has no real boundary, just set them to U32_MAX.
1345 *
1346 * The split happens for real compressed bio, which happens in
1347 * btrfs_submit_compressed_read/write().
1348 */
1349 if (bio_ctrl->compress_type != BTRFS_COMPRESS_NONE) {
1350 bio_ctrl->len_to_oe_boundary = U32_MAX;
1351 bio_ctrl->len_to_stripe_boundary = U32_MAX;
1352 return 0;
1353 }
1354 em = btrfs_get_chunk_map(fs_info, logical, fs_info->sectorsize);
1355 if (IS_ERR(em))
1356 return PTR_ERR(em);
1357 ret = btrfs_get_io_geometry(fs_info, em, btrfs_op(bio_ctrl->bio),
1358 logical, &geom);
1359 free_extent_map(em);
1360 if (ret < 0) {
1361 return ret;
1362 }
1363 if (geom.len > U32_MAX)
1364 bio_ctrl->len_to_stripe_boundary = U32_MAX;
1365 else
1366 bio_ctrl->len_to_stripe_boundary = (u32)geom.len;
1367
1368 if (bio_op(bio_ctrl->bio) != REQ_OP_ZONE_APPEND) {
1369 bio_ctrl->len_to_oe_boundary = U32_MAX;
1370 return 0;
1371 }
1372
1373 /* Ordered extent not yet created, so we're good */
1374 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
1375 if (!ordered) {
1376 bio_ctrl->len_to_oe_boundary = U32_MAX;
1377 return 0;
1378 }
1379
1380 bio_ctrl->len_to_oe_boundary = min_t(u32, U32_MAX,
1381 ordered->disk_bytenr + ordered->disk_num_bytes - logical);
1382 btrfs_put_ordered_extent(ordered);
1383 return 0;
1384}
1385
1386static int alloc_new_bio(struct btrfs_inode *inode,
1387 struct btrfs_bio_ctrl *bio_ctrl,
1388 struct writeback_control *wbc,
1389 blk_opf_t opf,
1390 u64 disk_bytenr, u32 offset, u64 file_offset,
1391 enum btrfs_compression_type compress_type)
1392{
1393 struct btrfs_fs_info *fs_info = inode->root->fs_info;
1394 struct bio *bio;
1395 int ret;
1396
1397 ASSERT(bio_ctrl->end_io_func);
1398
1399 bio = btrfs_bio_alloc(BIO_MAX_VECS, opf, bio_ctrl->end_io_func, NULL);
1400 /*
1401 * For compressed page range, its disk_bytenr is always @disk_bytenr
1402 * passed in, no matter if we have added any range into previous bio.
1403 */
1404 if (compress_type != BTRFS_COMPRESS_NONE)
1405 bio->bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
1406 else
1407 bio->bi_iter.bi_sector = (disk_bytenr + offset) >> SECTOR_SHIFT;
1408 bio_ctrl->bio = bio;
1409 bio_ctrl->compress_type = compress_type;
1410 ret = calc_bio_boundaries(bio_ctrl, inode, file_offset);
1411 if (ret < 0)
1412 goto error;
1413
1414 if (wbc) {
1415 /*
1416 * For Zone append we need the correct block_device that we are
1417 * going to write to set in the bio to be able to respect the
1418 * hardware limitation. Look it up here:
1419 */
1420 if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
1421 struct btrfs_device *dev;
1422
1423 dev = btrfs_zoned_get_device(fs_info, disk_bytenr,
1424 fs_info->sectorsize);
1425 if (IS_ERR(dev)) {
1426 ret = PTR_ERR(dev);
1427 goto error;
1428 }
1429
1430 bio_set_dev(bio, dev->bdev);
1431 } else {
1432 /*
1433 * Otherwise pick the last added device to support
1434 * cgroup writeback. For multi-device file systems this
1435 * means blk-cgroup policies have to always be set on the
1436 * last added/replaced device. This is a bit odd but has
1437 * been like that for a long time.
1438 */
1439 bio_set_dev(bio, fs_info->fs_devices->latest_dev->bdev);
1440 }
1441 wbc_init_bio(wbc, bio);
1442 } else {
1443 ASSERT(bio_op(bio) != REQ_OP_ZONE_APPEND);
1444 }
1445 return 0;
1446error:
1447 bio_ctrl->bio = NULL;
1448 btrfs_bio_end_io(btrfs_bio(bio), errno_to_blk_status(ret));
1449 return ret;
1450}
1451
1452/*
1453 * @opf: bio REQ_OP_* and REQ_* flags as one value
1454 * @wbc: optional writeback control for io accounting
1455 * @disk_bytenr: logical bytenr where the write will be
1456 * @page: page to add to the bio
1457 * @size: portion of page that we want to write to
1458 * @pg_offset: offset of the new bio or to check whether we are adding
1459 * a contiguous page to the previous one
1460 * @compress_type: compress type for current bio
1461 *
1462 * The will either add the page into the existing @bio_ctrl->bio, or allocate a
1463 * new one in @bio_ctrl->bio.
1464 * The mirror number for this IO should already be initizlied in
1465 * @bio_ctrl->mirror_num.
1466 */
1467static int submit_extent_page(blk_opf_t opf,
1468 struct writeback_control *wbc,
1469 struct btrfs_bio_ctrl *bio_ctrl,
1470 u64 disk_bytenr, struct page *page,
1471 size_t size, unsigned long pg_offset,
1472 enum btrfs_compression_type compress_type,
1473 bool force_bio_submit)
1474{
1475 int ret = 0;
1476 struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
1477 unsigned int cur = pg_offset;
1478
1479 ASSERT(bio_ctrl);
1480
1481 ASSERT(pg_offset < PAGE_SIZE && size <= PAGE_SIZE &&
1482 pg_offset + size <= PAGE_SIZE);
1483
1484 ASSERT(bio_ctrl->end_io_func);
1485
1486 if (force_bio_submit)
1487 submit_one_bio(bio_ctrl);
1488
1489 while (cur < pg_offset + size) {
1490 u32 offset = cur - pg_offset;
1491 int added;
1492
1493 /* Allocate new bio if needed */
1494 if (!bio_ctrl->bio) {
1495 ret = alloc_new_bio(inode, bio_ctrl, wbc, opf,
1496 disk_bytenr, offset,
1497 page_offset(page) + cur,
1498 compress_type);
1499 if (ret < 0)
1500 return ret;
1501 }
1502 /*
1503 * We must go through btrfs_bio_add_page() to ensure each
1504 * page range won't cross various boundaries.
1505 */
1506 if (compress_type != BTRFS_COMPRESS_NONE)
1507 added = btrfs_bio_add_page(bio_ctrl, page, disk_bytenr,
1508 size - offset, pg_offset + offset,
1509 compress_type);
1510 else
1511 added = btrfs_bio_add_page(bio_ctrl, page,
1512 disk_bytenr + offset, size - offset,
1513 pg_offset + offset, compress_type);
1514
1515 /* Metadata page range should never be split */
1516 if (!is_data_inode(&inode->vfs_inode))
1517 ASSERT(added == 0 || added == size - offset);
1518
1519 /* At least we added some page, update the account */
1520 if (wbc && added)
1521 wbc_account_cgroup_owner(wbc, page, added);
1522
1523 /* We have reached boundary, submit right now */
1524 if (added < size - offset) {
1525 /* The bio should contain some page(s) */
1526 ASSERT(bio_ctrl->bio->bi_iter.bi_size);
1527 submit_one_bio(bio_ctrl);
1528 }
1529 cur += added;
1530 }
1531 return 0;
1532}
1533
1534static int attach_extent_buffer_page(struct extent_buffer *eb,
1535 struct page *page,
1536 struct btrfs_subpage *prealloc)
1537{
1538 struct btrfs_fs_info *fs_info = eb->fs_info;
1539 int ret = 0;
1540
1541 /*
1542 * If the page is mapped to btree inode, we should hold the private
1543 * lock to prevent race.
1544 * For cloned or dummy extent buffers, their pages are not mapped and
1545 * will not race with any other ebs.
1546 */
1547 if (page->mapping)
1548 lockdep_assert_held(&page->mapping->private_lock);
1549
1550 if (fs_info->nodesize >= PAGE_SIZE) {
1551 if (!PagePrivate(page))
1552 attach_page_private(page, eb);
1553 else
1554 WARN_ON(page->private != (unsigned long)eb);
1555 return 0;
1556 }
1557
1558 /* Already mapped, just free prealloc */
1559 if (PagePrivate(page)) {
1560 btrfs_free_subpage(prealloc);
1561 return 0;
1562 }
1563
1564 if (prealloc)
1565 /* Has preallocated memory for subpage */
1566 attach_page_private(page, prealloc);
1567 else
1568 /* Do new allocation to attach subpage */
1569 ret = btrfs_attach_subpage(fs_info, page,
1570 BTRFS_SUBPAGE_METADATA);
1571 return ret;
1572}
1573
1574int set_page_extent_mapped(struct page *page)
1575{
1576 struct btrfs_fs_info *fs_info;
1577
1578 ASSERT(page->mapping);
1579
1580 if (PagePrivate(page))
1581 return 0;
1582
1583 fs_info = btrfs_sb(page->mapping->host->i_sb);
1584
1585 if (btrfs_is_subpage(fs_info, page))
1586 return btrfs_attach_subpage(fs_info, page, BTRFS_SUBPAGE_DATA);
1587
1588 attach_page_private(page, (void *)EXTENT_PAGE_PRIVATE);
1589 return 0;
1590}
1591
1592void clear_page_extent_mapped(struct page *page)
1593{
1594 struct btrfs_fs_info *fs_info;
1595
1596 ASSERT(page->mapping);
1597
1598 if (!PagePrivate(page))
1599 return;
1600
1601 fs_info = btrfs_sb(page->mapping->host->i_sb);
1602 if (btrfs_is_subpage(fs_info, page))
1603 return btrfs_detach_subpage(fs_info, page);
1604
1605 detach_page_private(page);
1606}
1607
1608static struct extent_map *
1609__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
1610 u64 start, u64 len, struct extent_map **em_cached)
1611{
1612 struct extent_map *em;
1613
1614 if (em_cached && *em_cached) {
1615 em = *em_cached;
1616 if (extent_map_in_tree(em) && start >= em->start &&
1617 start < extent_map_end(em)) {
1618 refcount_inc(&em->refs);
1619 return em;
1620 }
1621
1622 free_extent_map(em);
1623 *em_cached = NULL;
1624 }
1625
1626 em = btrfs_get_extent(BTRFS_I(inode), page, pg_offset, start, len);
1627 if (em_cached && !IS_ERR(em)) {
1628 BUG_ON(*em_cached);
1629 refcount_inc(&em->refs);
1630 *em_cached = em;
1631 }
1632 return em;
1633}
1634/*
1635 * basic readpage implementation. Locked extent state structs are inserted
1636 * into the tree that are removed when the IO is done (by the end_io
1637 * handlers)
1638 * XXX JDM: This needs looking at to ensure proper page locking
1639 * return 0 on success, otherwise return error
1640 */
1641static int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
1642 struct btrfs_bio_ctrl *bio_ctrl,
1643 blk_opf_t read_flags, u64 *prev_em_start)
1644{
1645 struct inode *inode = page->mapping->host;
1646 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1647 u64 start = page_offset(page);
1648 const u64 end = start + PAGE_SIZE - 1;
1649 u64 cur = start;
1650 u64 extent_offset;
1651 u64 last_byte = i_size_read(inode);
1652 u64 block_start;
1653 struct extent_map *em;
1654 int ret = 0;
1655 size_t pg_offset = 0;
1656 size_t iosize;
1657 size_t blocksize = inode->i_sb->s_blocksize;
1658 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
1659
1660 ret = set_page_extent_mapped(page);
1661 if (ret < 0) {
1662 unlock_extent(tree, start, end, NULL);
1663 btrfs_page_set_error(fs_info, page, start, PAGE_SIZE);
1664 unlock_page(page);
1665 goto out;
1666 }
1667
1668 if (page->index == last_byte >> PAGE_SHIFT) {
1669 size_t zero_offset = offset_in_page(last_byte);
1670
1671 if (zero_offset) {
1672 iosize = PAGE_SIZE - zero_offset;
1673 memzero_page(page, zero_offset, iosize);
1674 }
1675 }
1676 bio_ctrl->end_io_func = end_bio_extent_readpage;
1677 begin_page_read(fs_info, page);
1678 while (cur <= end) {
1679 unsigned long this_bio_flag = 0;
1680 bool force_bio_submit = false;
1681 u64 disk_bytenr;
1682
1683 ASSERT(IS_ALIGNED(cur, fs_info->sectorsize));
1684 if (cur >= last_byte) {
1685 iosize = PAGE_SIZE - pg_offset;
1686 memzero_page(page, pg_offset, iosize);
1687 unlock_extent(tree, cur, cur + iosize - 1, NULL);
1688 end_page_read(page, true, cur, iosize);
1689 break;
1690 }
1691 em = __get_extent_map(inode, page, pg_offset, cur,
1692 end - cur + 1, em_cached);
1693 if (IS_ERR(em)) {
1694 unlock_extent(tree, cur, end, NULL);
1695 end_page_read(page, false, cur, end + 1 - cur);
1696 ret = PTR_ERR(em);
1697 break;
1698 }
1699 extent_offset = cur - em->start;
1700 BUG_ON(extent_map_end(em) <= cur);
1701 BUG_ON(end < cur);
1702
1703 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
1704 this_bio_flag = em->compress_type;
1705
1706 iosize = min(extent_map_end(em) - cur, end - cur + 1);
1707 iosize = ALIGN(iosize, blocksize);
1708 if (this_bio_flag != BTRFS_COMPRESS_NONE)
1709 disk_bytenr = em->block_start;
1710 else
1711 disk_bytenr = em->block_start + extent_offset;
1712 block_start = em->block_start;
1713 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
1714 block_start = EXTENT_MAP_HOLE;
1715
1716 /*
1717 * If we have a file range that points to a compressed extent
1718 * and it's followed by a consecutive file range that points
1719 * to the same compressed extent (possibly with a different
1720 * offset and/or length, so it either points to the whole extent
1721 * or only part of it), we must make sure we do not submit a
1722 * single bio to populate the pages for the 2 ranges because
1723 * this makes the compressed extent read zero out the pages
1724 * belonging to the 2nd range. Imagine the following scenario:
1725 *
1726 * File layout
1727 * [0 - 8K] [8K - 24K]
1728 * | |
1729 * | |
1730 * points to extent X, points to extent X,
1731 * offset 4K, length of 8K offset 0, length 16K
1732 *
1733 * [extent X, compressed length = 4K uncompressed length = 16K]
1734 *
1735 * If the bio to read the compressed extent covers both ranges,
1736 * it will decompress extent X into the pages belonging to the
1737 * first range and then it will stop, zeroing out the remaining
1738 * pages that belong to the other range that points to extent X.
1739 * So here we make sure we submit 2 bios, one for the first
1740 * range and another one for the third range. Both will target
1741 * the same physical extent from disk, but we can't currently
1742 * make the compressed bio endio callback populate the pages
1743 * for both ranges because each compressed bio is tightly
1744 * coupled with a single extent map, and each range can have
1745 * an extent map with a different offset value relative to the
1746 * uncompressed data of our extent and different lengths. This
1747 * is a corner case so we prioritize correctness over
1748 * non-optimal behavior (submitting 2 bios for the same extent).
1749 */
1750 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
1751 prev_em_start && *prev_em_start != (u64)-1 &&
1752 *prev_em_start != em->start)
1753 force_bio_submit = true;
1754
1755 if (prev_em_start)
1756 *prev_em_start = em->start;
1757
1758 free_extent_map(em);
1759 em = NULL;
1760
1761 /* we've found a hole, just zero and go on */
1762 if (block_start == EXTENT_MAP_HOLE) {
1763 memzero_page(page, pg_offset, iosize);
1764
1765 unlock_extent(tree, cur, cur + iosize - 1, NULL);
1766 end_page_read(page, true, cur, iosize);
1767 cur = cur + iosize;
1768 pg_offset += iosize;
1769 continue;
1770 }
1771 /* the get_extent function already copied into the page */
1772 if (block_start == EXTENT_MAP_INLINE) {
1773 unlock_extent(tree, cur, cur + iosize - 1, NULL);
1774 end_page_read(page, true, cur, iosize);
1775 cur = cur + iosize;
1776 pg_offset += iosize;
1777 continue;
1778 }
1779
1780 ret = submit_extent_page(REQ_OP_READ | read_flags, NULL,
1781 bio_ctrl, disk_bytenr, page, iosize,
1782 pg_offset, this_bio_flag,
1783 force_bio_submit);
1784 if (ret) {
1785 /*
1786 * We have to unlock the remaining range, or the page
1787 * will never be unlocked.
1788 */
1789 unlock_extent(tree, cur, end, NULL);
1790 end_page_read(page, false, cur, end + 1 - cur);
1791 goto out;
1792 }
1793 cur = cur + iosize;
1794 pg_offset += iosize;
1795 }
1796out:
1797 return ret;
1798}
1799
1800int btrfs_read_folio(struct file *file, struct folio *folio)
1801{
1802 struct page *page = &folio->page;
1803 struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
1804 u64 start = page_offset(page);
1805 u64 end = start + PAGE_SIZE - 1;
1806 struct btrfs_bio_ctrl bio_ctrl = { 0 };
1807 int ret;
1808
1809 btrfs_lock_and_flush_ordered_range(inode, start, end, NULL);
1810
1811 ret = btrfs_do_readpage(page, NULL, &bio_ctrl, 0, NULL);
1812 /*
1813 * If btrfs_do_readpage() failed we will want to submit the assembled
1814 * bio to do the cleanup.
1815 */
1816 submit_one_bio(&bio_ctrl);
1817 return ret;
1818}
1819
1820static inline void contiguous_readpages(struct page *pages[], int nr_pages,
1821 u64 start, u64 end,
1822 struct extent_map **em_cached,
1823 struct btrfs_bio_ctrl *bio_ctrl,
1824 u64 *prev_em_start)
1825{
1826 struct btrfs_inode *inode = BTRFS_I(pages[0]->mapping->host);
1827 int index;
1828
1829 btrfs_lock_and_flush_ordered_range(inode, start, end, NULL);
1830
1831 for (index = 0; index < nr_pages; index++) {
1832 btrfs_do_readpage(pages[index], em_cached, bio_ctrl,
1833 REQ_RAHEAD, prev_em_start);
1834 put_page(pages[index]);
1835 }
1836}
1837
1838/*
1839 * helper for __extent_writepage, doing all of the delayed allocation setup.
1840 *
1841 * This returns 1 if btrfs_run_delalloc_range function did all the work required
1842 * to write the page (copy into inline extent). In this case the IO has
1843 * been started and the page is already unlocked.
1844 *
1845 * This returns 0 if all went well (page still locked)
1846 * This returns < 0 if there were errors (page still locked)
1847 */
1848static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
1849 struct page *page, struct writeback_control *wbc)
1850{
1851 const u64 page_end = page_offset(page) + PAGE_SIZE - 1;
1852 u64 delalloc_start = page_offset(page);
1853 u64 delalloc_to_write = 0;
1854 /* How many pages are started by btrfs_run_delalloc_range() */
1855 unsigned long nr_written = 0;
1856 int ret;
1857 int page_started = 0;
1858
1859 while (delalloc_start < page_end) {
1860 u64 delalloc_end = page_end;
1861 bool found;
1862
1863 found = find_lock_delalloc_range(&inode->vfs_inode, page,
1864 &delalloc_start,
1865 &delalloc_end);
1866 if (!found) {
1867 delalloc_start = delalloc_end + 1;
1868 continue;
1869 }
1870 ret = btrfs_run_delalloc_range(inode, page, delalloc_start,
1871 delalloc_end, &page_started, &nr_written, wbc);
1872 if (ret) {
1873 btrfs_page_set_error(inode->root->fs_info, page,
1874 page_offset(page), PAGE_SIZE);
1875 return ret;
1876 }
1877 /*
1878 * delalloc_end is already one less than the total length, so
1879 * we don't subtract one from PAGE_SIZE
1880 */
1881 delalloc_to_write += (delalloc_end - delalloc_start +
1882 PAGE_SIZE) >> PAGE_SHIFT;
1883 delalloc_start = delalloc_end + 1;
1884 }
1885 if (wbc->nr_to_write < delalloc_to_write) {
1886 int thresh = 8192;
1887
1888 if (delalloc_to_write < thresh * 2)
1889 thresh = delalloc_to_write;
1890 wbc->nr_to_write = min_t(u64, delalloc_to_write,
1891 thresh);
1892 }
1893
1894 /* Did btrfs_run_dealloc_range() already unlock and start the IO? */
1895 if (page_started) {
1896 /*
1897 * We've unlocked the page, so we can't update the mapping's
1898 * writeback index, just update nr_to_write.
1899 */
1900 wbc->nr_to_write -= nr_written;
1901 return 1;
1902 }
1903
1904 return 0;
1905}
1906
1907/*
1908 * Find the first byte we need to write.
1909 *
1910 * For subpage, one page can contain several sectors, and
1911 * __extent_writepage_io() will just grab all extent maps in the page
1912 * range and try to submit all non-inline/non-compressed extents.
1913 *
1914 * This is a big problem for subpage, we shouldn't re-submit already written
1915 * data at all.
1916 * This function will lookup subpage dirty bit to find which range we really
1917 * need to submit.
1918 *
1919 * Return the next dirty range in [@start, @end).
1920 * If no dirty range is found, @start will be page_offset(page) + PAGE_SIZE.
1921 */
1922static void find_next_dirty_byte(struct btrfs_fs_info *fs_info,
1923 struct page *page, u64 *start, u64 *end)
1924{
1925 struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;
1926 struct btrfs_subpage_info *spi = fs_info->subpage_info;
1927 u64 orig_start = *start;
1928 /* Declare as unsigned long so we can use bitmap ops */
1929 unsigned long flags;
1930 int range_start_bit;
1931 int range_end_bit;
1932
1933 /*
1934 * For regular sector size == page size case, since one page only
1935 * contains one sector, we return the page offset directly.
1936 */
1937 if (!btrfs_is_subpage(fs_info, page)) {
1938 *start = page_offset(page);
1939 *end = page_offset(page) + PAGE_SIZE;
1940 return;
1941 }
1942
1943 range_start_bit = spi->dirty_offset +
1944 (offset_in_page(orig_start) >> fs_info->sectorsize_bits);
1945
1946 /* We should have the page locked, but just in case */
1947 spin_lock_irqsave(&subpage->lock, flags);
1948 bitmap_next_set_region(subpage->bitmaps, &range_start_bit, &range_end_bit,
1949 spi->dirty_offset + spi->bitmap_nr_bits);
1950 spin_unlock_irqrestore(&subpage->lock, flags);
1951
1952 range_start_bit -= spi->dirty_offset;
1953 range_end_bit -= spi->dirty_offset;
1954
1955 *start = page_offset(page) + range_start_bit * fs_info->sectorsize;
1956 *end = page_offset(page) + range_end_bit * fs_info->sectorsize;
1957}
1958
1959/*
1960 * helper for __extent_writepage. This calls the writepage start hooks,
1961 * and does the loop to map the page into extents and bios.
1962 *
1963 * We return 1 if the IO is started and the page is unlocked,
1964 * 0 if all went well (page still locked)
1965 * < 0 if there were errors (page still locked)
1966 */
1967static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
1968 struct page *page,
1969 struct writeback_control *wbc,
1970 struct btrfs_bio_ctrl *bio_ctrl,
1971 loff_t i_size,
1972 int *nr_ret)
1973{
1974 struct btrfs_fs_info *fs_info = inode->root->fs_info;
1975 u64 cur = page_offset(page);
1976 u64 end = cur + PAGE_SIZE - 1;
1977 u64 extent_offset;
1978 u64 block_start;
1979 struct extent_map *em;
1980 int saved_ret = 0;
1981 int ret = 0;
1982 int nr = 0;
1983 enum req_op op = REQ_OP_WRITE;
1984 const blk_opf_t write_flags = wbc_to_write_flags(wbc);
1985 bool has_error = false;
1986 bool compressed;
1987
1988 ret = btrfs_writepage_cow_fixup(page);
1989 if (ret) {
1990 /* Fixup worker will requeue */
1991 redirty_page_for_writepage(wbc, page);
1992 unlock_page(page);
1993 return 1;
1994 }
1995
1996 /*
1997 * we don't want to touch the inode after unlocking the page,
1998 * so we update the mapping writeback index now
1999 */
2000 wbc->nr_to_write--;
2001
2002 bio_ctrl->end_io_func = end_bio_extent_writepage;
2003 while (cur <= end) {
2004 u64 disk_bytenr;
2005 u64 em_end;
2006 u64 dirty_range_start = cur;
2007 u64 dirty_range_end;
2008 u32 iosize;
2009
2010 if (cur >= i_size) {
2011 btrfs_writepage_endio_finish_ordered(inode, page, cur,
2012 end, true);
2013 /*
2014 * This range is beyond i_size, thus we don't need to
2015 * bother writing back.
2016 * But we still need to clear the dirty subpage bit, or
2017 * the next time the page gets dirtied, we will try to
2018 * writeback the sectors with subpage dirty bits,
2019 * causing writeback without ordered extent.
2020 */
2021 btrfs_page_clear_dirty(fs_info, page, cur, end + 1 - cur);
2022 break;
2023 }
2024
2025 find_next_dirty_byte(fs_info, page, &dirty_range_start,
2026 &dirty_range_end);
2027 if (cur < dirty_range_start) {
2028 cur = dirty_range_start;
2029 continue;
2030 }
2031
2032 em = btrfs_get_extent(inode, NULL, 0, cur, end - cur + 1);
2033 if (IS_ERR(em)) {
2034 btrfs_page_set_error(fs_info, page, cur, end - cur + 1);
2035 ret = PTR_ERR_OR_ZERO(em);
2036 has_error = true;
2037 if (!saved_ret)
2038 saved_ret = ret;
2039 break;
2040 }
2041
2042 extent_offset = cur - em->start;
2043 em_end = extent_map_end(em);
2044 ASSERT(cur <= em_end);
2045 ASSERT(cur < end);
2046 ASSERT(IS_ALIGNED(em->start, fs_info->sectorsize));
2047 ASSERT(IS_ALIGNED(em->len, fs_info->sectorsize));
2048 block_start = em->block_start;
2049 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2050 disk_bytenr = em->block_start + extent_offset;
2051
2052 /*
2053 * Note that em_end from extent_map_end() and dirty_range_end from
2054 * find_next_dirty_byte() are all exclusive
2055 */
2056 iosize = min(min(em_end, end + 1), dirty_range_end) - cur;
2057
2058 if (btrfs_use_zone_append(inode, em->block_start))
2059 op = REQ_OP_ZONE_APPEND;
2060
2061 free_extent_map(em);
2062 em = NULL;
2063
2064 /*
2065 * compressed and inline extents are written through other
2066 * paths in the FS
2067 */
2068 if (compressed || block_start == EXTENT_MAP_HOLE ||
2069 block_start == EXTENT_MAP_INLINE) {
2070 if (compressed)
2071 nr++;
2072 else
2073 btrfs_writepage_endio_finish_ordered(inode,
2074 page, cur, cur + iosize - 1, true);
2075 btrfs_page_clear_dirty(fs_info, page, cur, iosize);
2076 cur += iosize;
2077 continue;
2078 }
2079
2080 btrfs_set_range_writeback(inode, cur, cur + iosize - 1);
2081 if (!PageWriteback(page)) {
2082 btrfs_err(inode->root->fs_info,
2083 "page %lu not writeback, cur %llu end %llu",
2084 page->index, cur, end);
2085 }
2086
2087 /*
2088 * Although the PageDirty bit is cleared before entering this
2089 * function, subpage dirty bit is not cleared.
2090 * So clear subpage dirty bit here so next time we won't submit
2091 * page for range already written to disk.
2092 */
2093 btrfs_page_clear_dirty(fs_info, page, cur, iosize);
2094
2095 ret = submit_extent_page(op | write_flags, wbc,
2096 bio_ctrl, disk_bytenr,
2097 page, iosize,
2098 cur - page_offset(page),
2099 0, false);
2100 if (ret) {
2101 has_error = true;
2102 if (!saved_ret)
2103 saved_ret = ret;
2104
2105 btrfs_page_set_error(fs_info, page, cur, iosize);
2106 if (PageWriteback(page))
2107 btrfs_page_clear_writeback(fs_info, page, cur,
2108 iosize);
2109 }
2110
2111 cur += iosize;
2112 nr++;
2113 }
2114 /*
2115 * If we finish without problem, we should not only clear page dirty,
2116 * but also empty subpage dirty bits
2117 */
2118 if (!has_error)
2119 btrfs_page_assert_not_dirty(fs_info, page);
2120 else
2121 ret = saved_ret;
2122 *nr_ret = nr;
2123 return ret;
2124}
2125
2126/*
2127 * the writepage semantics are similar to regular writepage. extent
2128 * records are inserted to lock ranges in the tree, and as dirty areas
2129 * are found, they are marked writeback. Then the lock bits are removed
2130 * and the end_io handler clears the writeback ranges
2131 *
2132 * Return 0 if everything goes well.
2133 * Return <0 for error.
2134 */
2135static int __extent_writepage(struct page *page, struct writeback_control *wbc,
2136 struct btrfs_bio_ctrl *bio_ctrl)
2137{
2138 struct folio *folio = page_folio(page);
2139 struct inode *inode = page->mapping->host;
2140 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2141 const u64 page_start = page_offset(page);
2142 const u64 page_end = page_start + PAGE_SIZE - 1;
2143 int ret;
2144 int nr = 0;
2145 size_t pg_offset;
2146 loff_t i_size = i_size_read(inode);
2147 unsigned long end_index = i_size >> PAGE_SHIFT;
2148
2149 trace___extent_writepage(page, inode, wbc);
2150
2151 WARN_ON(!PageLocked(page));
2152
2153 btrfs_page_clear_error(btrfs_sb(inode->i_sb), page,
2154 page_offset(page), PAGE_SIZE);
2155
2156 pg_offset = offset_in_page(i_size);
2157 if (page->index > end_index ||
2158 (page->index == end_index && !pg_offset)) {
2159 folio_invalidate(folio, 0, folio_size(folio));
2160 folio_unlock(folio);
2161 return 0;
2162 }
2163
2164 if (page->index == end_index)
2165 memzero_page(page, pg_offset, PAGE_SIZE - pg_offset);
2166
2167 ret = set_page_extent_mapped(page);
2168 if (ret < 0) {
2169 SetPageError(page);
2170 goto done;
2171 }
2172
2173 if (!bio_ctrl->extent_locked) {
2174 ret = writepage_delalloc(BTRFS_I(inode), page, wbc);
2175 if (ret == 1)
2176 return 0;
2177 if (ret)
2178 goto done;
2179 }
2180
2181 ret = __extent_writepage_io(BTRFS_I(inode), page, wbc, bio_ctrl, i_size,
2182 &nr);
2183 if (ret == 1)
2184 return 0;
2185
2186done:
2187 if (nr == 0) {
2188 /* make sure the mapping tag for page dirty gets cleared */
2189 set_page_writeback(page);
2190 end_page_writeback(page);
2191 }
2192 /*
2193 * Here we used to have a check for PageError() and then set @ret and
2194 * call end_extent_writepage().
2195 *
2196 * But in fact setting @ret here will cause different error paths
2197 * between subpage and regular sectorsize.
2198 *
2199 * For regular page size, we never submit current page, but only add
2200 * current page to current bio.
2201 * The bio submission can only happen in next page.
2202 * Thus if we hit the PageError() branch, @ret is already set to
2203 * non-zero value and will not get updated for regular sectorsize.
2204 *
2205 * But for subpage case, it's possible we submit part of current page,
2206 * thus can get PageError() set by submitted bio of the same page,
2207 * while our @ret is still 0.
2208 *
2209 * So here we unify the behavior and don't set @ret.
2210 * Error can still be properly passed to higher layer as page will
2211 * be set error, here we just don't handle the IO failure.
2212 *
2213 * NOTE: This is just a hotfix for subpage.
2214 * The root fix will be properly ending ordered extent when we hit
2215 * an error during writeback.
2216 *
2217 * But that needs a bigger refactoring, as we not only need to grab the
2218 * submitted OE, but also need to know exactly at which bytenr we hit
2219 * the error.
2220 * Currently the full page based __extent_writepage_io() is not
2221 * capable of that.
2222 */
2223 if (PageError(page))
2224 end_extent_writepage(page, ret, page_start, page_end);
2225 if (bio_ctrl->extent_locked) {
2226 /*
2227 * If bio_ctrl->extent_locked, it's from extent_write_locked_range(),
2228 * the page can either be locked by lock_page() or
2229 * process_one_page().
2230 * Let btrfs_page_unlock_writer() handle both cases.
2231 */
2232 ASSERT(wbc);
2233 btrfs_page_unlock_writer(fs_info, page, wbc->range_start,
2234 wbc->range_end + 1 - wbc->range_start);
2235 } else {
2236 unlock_page(page);
2237 }
2238 ASSERT(ret <= 0);
2239 return ret;
2240}
2241
2242void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
2243{
2244 wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
2245 TASK_UNINTERRUPTIBLE);
2246}
2247
2248static void end_extent_buffer_writeback(struct extent_buffer *eb)
2249{
2250 clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
2251 smp_mb__after_atomic();
2252 wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
2253}
2254
2255/*
2256 * Lock extent buffer status and pages for writeback.
2257 *
2258 * May try to flush write bio if we can't get the lock.
2259 *
2260 * Return 0 if the extent buffer doesn't need to be submitted.
2261 * (E.g. the extent buffer is not dirty)
2262 * Return >0 is the extent buffer is submitted to bio.
2263 * Return <0 if something went wrong, no page is locked.
2264 */
2265static noinline_for_stack int lock_extent_buffer_for_io(struct extent_buffer *eb,
2266 struct btrfs_bio_ctrl *bio_ctrl)
2267{
2268 struct btrfs_fs_info *fs_info = eb->fs_info;
2269 int i, num_pages;
2270 int flush = 0;
2271 int ret = 0;
2272
2273 if (!btrfs_try_tree_write_lock(eb)) {
2274 submit_write_bio(bio_ctrl, 0);
2275 flush = 1;
2276 btrfs_tree_lock(eb);
2277 }
2278
2279 if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
2280 btrfs_tree_unlock(eb);
2281 if (!bio_ctrl->sync_io)
2282 return 0;
2283 if (!flush) {
2284 submit_write_bio(bio_ctrl, 0);
2285 flush = 1;
2286 }
2287 while (1) {
2288 wait_on_extent_buffer_writeback(eb);
2289 btrfs_tree_lock(eb);
2290 if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
2291 break;
2292 btrfs_tree_unlock(eb);
2293 }
2294 }
2295
2296 /*
2297 * We need to do this to prevent races in people who check if the eb is
2298 * under IO since we can end up having no IO bits set for a short period
2299 * of time.
2300 */
2301 spin_lock(&eb->refs_lock);
2302 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
2303 set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
2304 spin_unlock(&eb->refs_lock);
2305 btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
2306 percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
2307 -eb->len,
2308 fs_info->dirty_metadata_batch);
2309 ret = 1;
2310 } else {
2311 spin_unlock(&eb->refs_lock);
2312 }
2313
2314 btrfs_tree_unlock(eb);
2315
2316 /*
2317 * Either we don't need to submit any tree block, or we're submitting
2318 * subpage eb.
2319 * Subpage metadata doesn't use page locking at all, so we can skip
2320 * the page locking.
2321 */
2322 if (!ret || fs_info->nodesize < PAGE_SIZE)
2323 return ret;
2324
2325 num_pages = num_extent_pages(eb);
2326 for (i = 0; i < num_pages; i++) {
2327 struct page *p = eb->pages[i];
2328
2329 if (!trylock_page(p)) {
2330 if (!flush) {
2331 submit_write_bio(bio_ctrl, 0);
2332 flush = 1;
2333 }
2334 lock_page(p);
2335 }
2336 }
2337
2338 return ret;
2339}
2340
2341static void set_btree_ioerr(struct page *page, struct extent_buffer *eb)
2342{
2343 struct btrfs_fs_info *fs_info = eb->fs_info;
2344
2345 btrfs_page_set_error(fs_info, page, eb->start, eb->len);
2346 if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
2347 return;
2348
2349 /*
2350 * A read may stumble upon this buffer later, make sure that it gets an
2351 * error and knows there was an error.
2352 */
2353 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
2354
2355 /*
2356 * We need to set the mapping with the io error as well because a write
2357 * error will flip the file system readonly, and then syncfs() will
2358 * return a 0 because we are readonly if we don't modify the err seq for
2359 * the superblock.
2360 */
2361 mapping_set_error(page->mapping, -EIO);
2362
2363 /*
2364 * If we error out, we should add back the dirty_metadata_bytes
2365 * to make it consistent.
2366 */
2367 percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
2368 eb->len, fs_info->dirty_metadata_batch);
2369
2370 /*
2371 * If writeback for a btree extent that doesn't belong to a log tree
2372 * failed, increment the counter transaction->eb_write_errors.
2373 * We do this because while the transaction is running and before it's
2374 * committing (when we call filemap_fdata[write|wait]_range against
2375 * the btree inode), we might have
2376 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
2377 * returns an error or an error happens during writeback, when we're
2378 * committing the transaction we wouldn't know about it, since the pages
2379 * can be no longer dirty nor marked anymore for writeback (if a
2380 * subsequent modification to the extent buffer didn't happen before the
2381 * transaction commit), which makes filemap_fdata[write|wait]_range not
2382 * able to find the pages tagged with SetPageError at transaction
2383 * commit time. So if this happens we must abort the transaction,
2384 * otherwise we commit a super block with btree roots that point to
2385 * btree nodes/leafs whose content on disk is invalid - either garbage
2386 * or the content of some node/leaf from a past generation that got
2387 * cowed or deleted and is no longer valid.
2388 *
2389 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
2390 * not be enough - we need to distinguish between log tree extents vs
2391 * non-log tree extents, and the next filemap_fdatawait_range() call
2392 * will catch and clear such errors in the mapping - and that call might
2393 * be from a log sync and not from a transaction commit. Also, checking
2394 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
2395 * not done and would not be reliable - the eb might have been released
2396 * from memory and reading it back again means that flag would not be
2397 * set (since it's a runtime flag, not persisted on disk).
2398 *
2399 * Using the flags below in the btree inode also makes us achieve the
2400 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
2401 * writeback for all dirty pages and before filemap_fdatawait_range()
2402 * is called, the writeback for all dirty pages had already finished
2403 * with errors - because we were not using AS_EIO/AS_ENOSPC,
2404 * filemap_fdatawait_range() would return success, as it could not know
2405 * that writeback errors happened (the pages were no longer tagged for
2406 * writeback).
2407 */
2408 switch (eb->log_index) {
2409 case -1:
2410 set_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags);
2411 break;
2412 case 0:
2413 set_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2414 break;
2415 case 1:
2416 set_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2417 break;
2418 default:
2419 BUG(); /* unexpected, logic error */
2420 }
2421}
2422
2423/*
2424 * The endio specific version which won't touch any unsafe spinlock in endio
2425 * context.
2426 */
2427static struct extent_buffer *find_extent_buffer_nolock(
2428 struct btrfs_fs_info *fs_info, u64 start)
2429{
2430 struct extent_buffer *eb;
2431
2432 rcu_read_lock();
2433 eb = radix_tree_lookup(&fs_info->buffer_radix,
2434 start >> fs_info->sectorsize_bits);
2435 if (eb && atomic_inc_not_zero(&eb->refs)) {
2436 rcu_read_unlock();
2437 return eb;
2438 }
2439 rcu_read_unlock();
2440 return NULL;
2441}
2442
2443/*
2444 * The endio function for subpage extent buffer write.
2445 *
2446 * Unlike end_bio_extent_buffer_writepage(), we only call end_page_writeback()
2447 * after all extent buffers in the page has finished their writeback.
2448 */
2449static void end_bio_subpage_eb_writepage(struct btrfs_bio *bbio)
2450{
2451 struct bio *bio = &bbio->bio;
2452 struct btrfs_fs_info *fs_info;
2453 struct bio_vec *bvec;
2454 struct bvec_iter_all iter_all;
2455
2456 fs_info = btrfs_sb(bio_first_page_all(bio)->mapping->host->i_sb);
2457 ASSERT(fs_info->nodesize < PAGE_SIZE);
2458
2459 ASSERT(!bio_flagged(bio, BIO_CLONED));
2460 bio_for_each_segment_all(bvec, bio, iter_all) {
2461 struct page *page = bvec->bv_page;
2462 u64 bvec_start = page_offset(page) + bvec->bv_offset;
2463 u64 bvec_end = bvec_start + bvec->bv_len - 1;
2464 u64 cur_bytenr = bvec_start;
2465
2466 ASSERT(IS_ALIGNED(bvec->bv_len, fs_info->nodesize));
2467
2468 /* Iterate through all extent buffers in the range */
2469 while (cur_bytenr <= bvec_end) {
2470 struct extent_buffer *eb;
2471 int done;
2472
2473 /*
2474 * Here we can't use find_extent_buffer(), as it may
2475 * try to lock eb->refs_lock, which is not safe in endio
2476 * context.
2477 */
2478 eb = find_extent_buffer_nolock(fs_info, cur_bytenr);
2479 ASSERT(eb);
2480
2481 cur_bytenr = eb->start + eb->len;
2482
2483 ASSERT(test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags));
2484 done = atomic_dec_and_test(&eb->io_pages);
2485 ASSERT(done);
2486
2487 if (bio->bi_status ||
2488 test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
2489 ClearPageUptodate(page);
2490 set_btree_ioerr(page, eb);
2491 }
2492
2493 btrfs_subpage_clear_writeback(fs_info, page, eb->start,
2494 eb->len);
2495 end_extent_buffer_writeback(eb);
2496 /*
2497 * free_extent_buffer() will grab spinlock which is not
2498 * safe in endio context. Thus here we manually dec
2499 * the ref.
2500 */
2501 atomic_dec(&eb->refs);
2502 }
2503 }
2504 bio_put(bio);
2505}
2506
2507static void end_bio_extent_buffer_writepage(struct btrfs_bio *bbio)
2508{
2509 struct bio *bio = &bbio->bio;
2510 struct bio_vec *bvec;
2511 struct extent_buffer *eb;
2512 int done;
2513 struct bvec_iter_all iter_all;
2514
2515 ASSERT(!bio_flagged(bio, BIO_CLONED));
2516 bio_for_each_segment_all(bvec, bio, iter_all) {
2517 struct page *page = bvec->bv_page;
2518
2519 eb = (struct extent_buffer *)page->private;
2520 BUG_ON(!eb);
2521 done = atomic_dec_and_test(&eb->io_pages);
2522
2523 if (bio->bi_status ||
2524 test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
2525 ClearPageUptodate(page);
2526 set_btree_ioerr(page, eb);
2527 }
2528
2529 end_page_writeback(page);
2530
2531 if (!done)
2532 continue;
2533
2534 end_extent_buffer_writeback(eb);
2535 }
2536
2537 bio_put(bio);
2538}
2539
2540static void prepare_eb_write(struct extent_buffer *eb)
2541{
2542 u32 nritems;
2543 unsigned long start;
2544 unsigned long end;
2545
2546 clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
2547 atomic_set(&eb->io_pages, num_extent_pages(eb));
2548
2549 /* Set btree blocks beyond nritems with 0 to avoid stale content */
2550 nritems = btrfs_header_nritems(eb);
2551 if (btrfs_header_level(eb) > 0) {
2552 end = btrfs_node_key_ptr_offset(eb, nritems);
2553 memzero_extent_buffer(eb, end, eb->len - end);
2554 } else {
2555 /*
2556 * Leaf:
2557 * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
2558 */
2559 start = btrfs_item_nr_offset(eb, nritems);
2560 end = btrfs_item_nr_offset(eb, 0);
2561 if (nritems == 0)
2562 end += BTRFS_LEAF_DATA_SIZE(eb->fs_info);
2563 else
2564 end += btrfs_item_offset(eb, nritems - 1);
2565 memzero_extent_buffer(eb, start, end - start);
2566 }
2567}
2568
2569/*
2570 * Unlike the work in write_one_eb(), we rely completely on extent locking.
2571 * Page locking is only utilized at minimum to keep the VMM code happy.
2572 */
2573static int write_one_subpage_eb(struct extent_buffer *eb,
2574 struct writeback_control *wbc,
2575 struct btrfs_bio_ctrl *bio_ctrl)
2576{
2577 struct btrfs_fs_info *fs_info = eb->fs_info;
2578 struct page *page = eb->pages[0];
2579 blk_opf_t write_flags = wbc_to_write_flags(wbc);
2580 bool no_dirty_ebs = false;
2581 int ret;
2582
2583 prepare_eb_write(eb);
2584
2585 /* clear_page_dirty_for_io() in subpage helper needs page locked */
2586 lock_page(page);
2587 btrfs_subpage_set_writeback(fs_info, page, eb->start, eb->len);
2588
2589 /* Check if this is the last dirty bit to update nr_written */
2590 no_dirty_ebs = btrfs_subpage_clear_and_test_dirty(fs_info, page,
2591 eb->start, eb->len);
2592 if (no_dirty_ebs)
2593 clear_page_dirty_for_io(page);
2594
2595 bio_ctrl->end_io_func = end_bio_subpage_eb_writepage;
2596
2597 ret = submit_extent_page(REQ_OP_WRITE | write_flags, wbc,
2598 bio_ctrl, eb->start, page, eb->len,
2599 eb->start - page_offset(page), 0, false);
2600 if (ret) {
2601 btrfs_subpage_clear_writeback(fs_info, page, eb->start, eb->len);
2602 set_btree_ioerr(page, eb);
2603 unlock_page(page);
2604
2605 if (atomic_dec_and_test(&eb->io_pages))
2606 end_extent_buffer_writeback(eb);
2607 return -EIO;
2608 }
2609 unlock_page(page);
2610 /*
2611 * Submission finished without problem, if no range of the page is
2612 * dirty anymore, we have submitted a page. Update nr_written in wbc.
2613 */
2614 if (no_dirty_ebs)
2615 wbc->nr_to_write--;
2616 return ret;
2617}
2618
2619static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
2620 struct writeback_control *wbc,
2621 struct btrfs_bio_ctrl *bio_ctrl)
2622{
2623 u64 disk_bytenr = eb->start;
2624 int i, num_pages;
2625 blk_opf_t write_flags = wbc_to_write_flags(wbc);
2626 int ret = 0;
2627
2628 prepare_eb_write(eb);
2629
2630 bio_ctrl->end_io_func = end_bio_extent_buffer_writepage;
2631
2632 num_pages = num_extent_pages(eb);
2633 for (i = 0; i < num_pages; i++) {
2634 struct page *p = eb->pages[i];
2635
2636 clear_page_dirty_for_io(p);
2637 set_page_writeback(p);
2638 ret = submit_extent_page(REQ_OP_WRITE | write_flags, wbc,
2639 bio_ctrl, disk_bytenr, p,
2640 PAGE_SIZE, 0, 0, false);
2641 if (ret) {
2642 set_btree_ioerr(p, eb);
2643 if (PageWriteback(p))
2644 end_page_writeback(p);
2645 if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
2646 end_extent_buffer_writeback(eb);
2647 ret = -EIO;
2648 break;
2649 }
2650 disk_bytenr += PAGE_SIZE;
2651 wbc->nr_to_write--;
2652 unlock_page(p);
2653 }
2654
2655 if (unlikely(ret)) {
2656 for (; i < num_pages; i++) {
2657 struct page *p = eb->pages[i];
2658 clear_page_dirty_for_io(p);
2659 unlock_page(p);
2660 }
2661 }
2662
2663 return ret;
2664}
2665
2666/*
2667 * Submit one subpage btree page.
2668 *
2669 * The main difference to submit_eb_page() is:
2670 * - Page locking
2671 * For subpage, we don't rely on page locking at all.
2672 *
2673 * - Flush write bio
2674 * We only flush bio if we may be unable to fit current extent buffers into
2675 * current bio.
2676 *
2677 * Return >=0 for the number of submitted extent buffers.
2678 * Return <0 for fatal error.
2679 */
2680static int submit_eb_subpage(struct page *page,
2681 struct writeback_control *wbc,
2682 struct btrfs_bio_ctrl *bio_ctrl)
2683{
2684 struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
2685 int submitted = 0;
2686 u64 page_start = page_offset(page);
2687 int bit_start = 0;
2688 int sectors_per_node = fs_info->nodesize >> fs_info->sectorsize_bits;
2689 int ret;
2690
2691 /* Lock and write each dirty extent buffers in the range */
2692 while (bit_start < fs_info->subpage_info->bitmap_nr_bits) {
2693 struct btrfs_subpage *subpage = (struct btrfs_subpage *)page->private;
2694 struct extent_buffer *eb;
2695 unsigned long flags;
2696 u64 start;
2697
2698 /*
2699 * Take private lock to ensure the subpage won't be detached
2700 * in the meantime.
2701 */
2702 spin_lock(&page->mapping->private_lock);
2703 if (!PagePrivate(page)) {
2704 spin_unlock(&page->mapping->private_lock);
2705 break;
2706 }
2707 spin_lock_irqsave(&subpage->lock, flags);
2708 if (!test_bit(bit_start + fs_info->subpage_info->dirty_offset,
2709 subpage->bitmaps)) {
2710 spin_unlock_irqrestore(&subpage->lock, flags);
2711 spin_unlock(&page->mapping->private_lock);
2712 bit_start++;
2713 continue;
2714 }
2715
2716 start = page_start + bit_start * fs_info->sectorsize;
2717 bit_start += sectors_per_node;
2718
2719 /*
2720 * Here we just want to grab the eb without touching extra
2721 * spin locks, so call find_extent_buffer_nolock().
2722 */
2723 eb = find_extent_buffer_nolock(fs_info, start);
2724 spin_unlock_irqrestore(&subpage->lock, flags);
2725 spin_unlock(&page->mapping->private_lock);
2726
2727 /*
2728 * The eb has already reached 0 refs thus find_extent_buffer()
2729 * doesn't return it. We don't need to write back such eb
2730 * anyway.
2731 */
2732 if (!eb)
2733 continue;
2734
2735 ret = lock_extent_buffer_for_io(eb, bio_ctrl);
2736 if (ret == 0) {
2737 free_extent_buffer(eb);
2738 continue;
2739 }
2740 if (ret < 0) {
2741 free_extent_buffer(eb);
2742 goto cleanup;
2743 }
2744 ret = write_one_subpage_eb(eb, wbc, bio_ctrl);
2745 free_extent_buffer(eb);
2746 if (ret < 0)
2747 goto cleanup;
2748 submitted++;
2749 }
2750 return submitted;
2751
2752cleanup:
2753 /* We hit error, end bio for the submitted extent buffers */
2754 submit_write_bio(bio_ctrl, ret);
2755 return ret;
2756}
2757
2758/*
2759 * Submit all page(s) of one extent buffer.
2760 *
2761 * @page: the page of one extent buffer
2762 * @eb_context: to determine if we need to submit this page, if current page
2763 * belongs to this eb, we don't need to submit
2764 *
2765 * The caller should pass each page in their bytenr order, and here we use
2766 * @eb_context to determine if we have submitted pages of one extent buffer.
2767 *
2768 * If we have, we just skip until we hit a new page that doesn't belong to
2769 * current @eb_context.
2770 *
2771 * If not, we submit all the page(s) of the extent buffer.
2772 *
2773 * Return >0 if we have submitted the extent buffer successfully.
2774 * Return 0 if we don't need to submit the page, as it's already submitted by
2775 * previous call.
2776 * Return <0 for fatal error.
2777 */
2778static int submit_eb_page(struct page *page, struct writeback_control *wbc,
2779 struct btrfs_bio_ctrl *bio_ctrl,
2780 struct extent_buffer **eb_context)
2781{
2782 struct address_space *mapping = page->mapping;
2783 struct btrfs_block_group *cache = NULL;
2784 struct extent_buffer *eb;
2785 int ret;
2786
2787 if (!PagePrivate(page))
2788 return 0;
2789
2790 if (btrfs_sb(page->mapping->host->i_sb)->nodesize < PAGE_SIZE)
2791 return submit_eb_subpage(page, wbc, bio_ctrl);
2792
2793 spin_lock(&mapping->private_lock);
2794 if (!PagePrivate(page)) {
2795 spin_unlock(&mapping->private_lock);
2796 return 0;
2797 }
2798
2799 eb = (struct extent_buffer *)page->private;
2800
2801 /*
2802 * Shouldn't happen and normally this would be a BUG_ON but no point
2803 * crashing the machine for something we can survive anyway.
2804 */
2805 if (WARN_ON(!eb)) {
2806 spin_unlock(&mapping->private_lock);
2807 return 0;
2808 }
2809
2810 if (eb == *eb_context) {
2811 spin_unlock(&mapping->private_lock);
2812 return 0;
2813 }
2814 ret = atomic_inc_not_zero(&eb->refs);
2815 spin_unlock(&mapping->private_lock);
2816 if (!ret)
2817 return 0;
2818
2819 if (!btrfs_check_meta_write_pointer(eb->fs_info, eb, &cache)) {
2820 /*
2821 * If for_sync, this hole will be filled with
2822 * trasnsaction commit.
2823 */
2824 if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
2825 ret = -EAGAIN;
2826 else
2827 ret = 0;
2828 free_extent_buffer(eb);
2829 return ret;
2830 }
2831
2832 *eb_context = eb;
2833
2834 ret = lock_extent_buffer_for_io(eb, bio_ctrl);
2835 if (ret <= 0) {
2836 btrfs_revert_meta_write_pointer(cache, eb);
2837 if (cache)
2838 btrfs_put_block_group(cache);
2839 free_extent_buffer(eb);
2840 return ret;
2841 }
2842 if (cache) {
2843 /*
2844 * Implies write in zoned mode. Mark the last eb in a block group.
2845 */
2846 btrfs_schedule_zone_finish_bg(cache, eb);
2847 btrfs_put_block_group(cache);
2848 }
2849 ret = write_one_eb(eb, wbc, bio_ctrl);
2850 free_extent_buffer(eb);
2851 if (ret < 0)
2852 return ret;
2853 return 1;
2854}
2855
2856int btree_write_cache_pages(struct address_space *mapping,
2857 struct writeback_control *wbc)
2858{
2859 struct extent_buffer *eb_context = NULL;
2860 struct btrfs_bio_ctrl bio_ctrl = {
2861 .extent_locked = 0,
2862 .sync_io = (wbc->sync_mode == WB_SYNC_ALL),
2863 };
2864 struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
2865 int ret = 0;
2866 int done = 0;
2867 int nr_to_write_done = 0;
2868 struct pagevec pvec;
2869 int nr_pages;
2870 pgoff_t index;
2871 pgoff_t end; /* Inclusive */
2872 int scanned = 0;
2873 xa_mark_t tag;
2874
2875 pagevec_init(&pvec);
2876 if (wbc->range_cyclic) {
2877 index = mapping->writeback_index; /* Start from prev offset */
2878 end = -1;
2879 /*
2880 * Start from the beginning does not need to cycle over the
2881 * range, mark it as scanned.
2882 */
2883 scanned = (index == 0);
2884 } else {
2885 index = wbc->range_start >> PAGE_SHIFT;
2886 end = wbc->range_end >> PAGE_SHIFT;
2887 scanned = 1;
2888 }
2889 if (wbc->sync_mode == WB_SYNC_ALL)
2890 tag = PAGECACHE_TAG_TOWRITE;
2891 else
2892 tag = PAGECACHE_TAG_DIRTY;
2893 btrfs_zoned_meta_io_lock(fs_info);
2894retry:
2895 if (wbc->sync_mode == WB_SYNC_ALL)
2896 tag_pages_for_writeback(mapping, index, end);
2897 while (!done && !nr_to_write_done && (index <= end) &&
2898 (nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
2899 tag))) {
2900 unsigned i;
2901
2902 for (i = 0; i < nr_pages; i++) {
2903 struct page *page = pvec.pages[i];
2904
2905 ret = submit_eb_page(page, wbc, &bio_ctrl, &eb_context);
2906 if (ret == 0)
2907 continue;
2908 if (ret < 0) {
2909 done = 1;
2910 break;
2911 }
2912
2913 /*
2914 * the filesystem may choose to bump up nr_to_write.
2915 * We have to make sure to honor the new nr_to_write
2916 * at any time
2917 */
2918 nr_to_write_done = wbc->nr_to_write <= 0;
2919 }
2920 pagevec_release(&pvec);
2921 cond_resched();
2922 }
2923 if (!scanned && !done) {
2924 /*
2925 * We hit the last page and there is more work to be done: wrap
2926 * back to the start of the file
2927 */
2928 scanned = 1;
2929 index = 0;
2930 goto retry;
2931 }
2932 /*
2933 * If something went wrong, don't allow any metadata write bio to be
2934 * submitted.
2935 *
2936 * This would prevent use-after-free if we had dirty pages not
2937 * cleaned up, which can still happen by fuzzed images.
2938 *
2939 * - Bad extent tree
2940 * Allowing existing tree block to be allocated for other trees.
2941 *
2942 * - Log tree operations
2943 * Exiting tree blocks get allocated to log tree, bumps its
2944 * generation, then get cleaned in tree re-balance.
2945 * Such tree block will not be written back, since it's clean,
2946 * thus no WRITTEN flag set.
2947 * And after log writes back, this tree block is not traced by
2948 * any dirty extent_io_tree.
2949 *
2950 * - Offending tree block gets re-dirtied from its original owner
2951 * Since it has bumped generation, no WRITTEN flag, it can be
2952 * reused without COWing. This tree block will not be traced
2953 * by btrfs_transaction::dirty_pages.
2954 *
2955 * Now such dirty tree block will not be cleaned by any dirty
2956 * extent io tree. Thus we don't want to submit such wild eb
2957 * if the fs already has error.
2958 *
2959 * We can get ret > 0 from submit_extent_page() indicating how many ebs
2960 * were submitted. Reset it to 0 to avoid false alerts for the caller.
2961 */
2962 if (ret > 0)
2963 ret = 0;
2964 if (!ret && BTRFS_FS_ERROR(fs_info))
2965 ret = -EROFS;
2966 submit_write_bio(&bio_ctrl, ret);
2967
2968 btrfs_zoned_meta_io_unlock(fs_info);
2969 return ret;
2970}
2971
2972/*
2973 * Walk the list of dirty pages of the given address space and write all of them.
2974 *
2975 * @mapping: address space structure to write
2976 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
2977 * @bio_ctrl: holds context for the write, namely the bio
2978 *
2979 * If a page is already under I/O, write_cache_pages() skips it, even
2980 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
2981 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
2982 * and msync() need to guarantee that all the data which was dirty at the time
2983 * the call was made get new I/O started against them. If wbc->sync_mode is
2984 * WB_SYNC_ALL then we were called for data integrity and we must wait for
2985 * existing IO to complete.
2986 */
2987static int extent_write_cache_pages(struct address_space *mapping,
2988 struct writeback_control *wbc,
2989 struct btrfs_bio_ctrl *bio_ctrl)
2990{
2991 struct inode *inode = mapping->host;
2992 int ret = 0;
2993 int done = 0;
2994 int nr_to_write_done = 0;
2995 struct pagevec pvec;
2996 int nr_pages;
2997 pgoff_t index;
2998 pgoff_t end; /* Inclusive */
2999 pgoff_t done_index;
3000 int range_whole = 0;
3001 int scanned = 0;
3002 xa_mark_t tag;
3003
3004 /*
3005 * We have to hold onto the inode so that ordered extents can do their
3006 * work when the IO finishes. The alternative to this is failing to add
3007 * an ordered extent if the igrab() fails there and that is a huge pain
3008 * to deal with, so instead just hold onto the inode throughout the
3009 * writepages operation. If it fails here we are freeing up the inode
3010 * anyway and we'd rather not waste our time writing out stuff that is
3011 * going to be truncated anyway.
3012 */
3013 if (!igrab(inode))
3014 return 0;
3015
3016 pagevec_init(&pvec);
3017 if (wbc->range_cyclic) {
3018 index = mapping->writeback_index; /* Start from prev offset */
3019 end = -1;
3020 /*
3021 * Start from the beginning does not need to cycle over the
3022 * range, mark it as scanned.
3023 */
3024 scanned = (index == 0);
3025 } else {
3026 index = wbc->range_start >> PAGE_SHIFT;
3027 end = wbc->range_end >> PAGE_SHIFT;
3028 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
3029 range_whole = 1;
3030 scanned = 1;
3031 }
3032
3033 /*
3034 * We do the tagged writepage as long as the snapshot flush bit is set
3035 * and we are the first one who do the filemap_flush() on this inode.
3036 *
3037 * The nr_to_write == LONG_MAX is needed to make sure other flushers do
3038 * not race in and drop the bit.
3039 */
3040 if (range_whole && wbc->nr_to_write == LONG_MAX &&
3041 test_and_clear_bit(BTRFS_INODE_SNAPSHOT_FLUSH,
3042 &BTRFS_I(inode)->runtime_flags))
3043 wbc->tagged_writepages = 1;
3044
3045 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
3046 tag = PAGECACHE_TAG_TOWRITE;
3047 else
3048 tag = PAGECACHE_TAG_DIRTY;
3049retry:
3050 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
3051 tag_pages_for_writeback(mapping, index, end);
3052 done_index = index;
3053 while (!done && !nr_to_write_done && (index <= end) &&
3054 (nr_pages = pagevec_lookup_range_tag(&pvec, mapping,
3055 &index, end, tag))) {
3056 unsigned i;
3057
3058 for (i = 0; i < nr_pages; i++) {
3059 struct page *page = pvec.pages[i];
3060
3061 done_index = page->index + 1;
3062 /*
3063 * At this point we hold neither the i_pages lock nor
3064 * the page lock: the page may be truncated or
3065 * invalidated (changing page->mapping to NULL),
3066 * or even swizzled back from swapper_space to
3067 * tmpfs file mapping
3068 */
3069 if (!trylock_page(page)) {
3070 submit_write_bio(bio_ctrl, 0);
3071 lock_page(page);
3072 }
3073
3074 if (unlikely(page->mapping != mapping)) {
3075 unlock_page(page);
3076 continue;
3077 }
3078
3079 if (wbc->sync_mode != WB_SYNC_NONE) {
3080 if (PageWriteback(page))
3081 submit_write_bio(bio_ctrl, 0);
3082 wait_on_page_writeback(page);
3083 }
3084
3085 if (PageWriteback(page) ||
3086 !clear_page_dirty_for_io(page)) {
3087 unlock_page(page);
3088 continue;
3089 }
3090
3091 ret = __extent_writepage(page, wbc, bio_ctrl);
3092 if (ret < 0) {
3093 done = 1;
3094 break;
3095 }
3096
3097 /*
3098 * the filesystem may choose to bump up nr_to_write.
3099 * We have to make sure to honor the new nr_to_write
3100 * at any time
3101 */
3102 nr_to_write_done = wbc->nr_to_write <= 0;
3103 }
3104 pagevec_release(&pvec);
3105 cond_resched();
3106 }
3107 if (!scanned && !done) {
3108 /*
3109 * We hit the last page and there is more work to be done: wrap
3110 * back to the start of the file
3111 */
3112 scanned = 1;
3113 index = 0;
3114
3115 /*
3116 * If we're looping we could run into a page that is locked by a
3117 * writer and that writer could be waiting on writeback for a
3118 * page in our current bio, and thus deadlock, so flush the
3119 * write bio here.
3120 */
3121 submit_write_bio(bio_ctrl, 0);
3122 goto retry;
3123 }
3124
3125 if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
3126 mapping->writeback_index = done_index;
3127
3128 btrfs_add_delayed_iput(BTRFS_I(inode));
3129 return ret;
3130}
3131
3132/*
3133 * Submit the pages in the range to bio for call sites which delalloc range has
3134 * already been ran (aka, ordered extent inserted) and all pages are still
3135 * locked.
3136 */
3137int extent_write_locked_range(struct inode *inode, u64 start, u64 end)
3138{
3139 bool found_error = false;
3140 int first_error = 0;
3141 int ret = 0;
3142 struct address_space *mapping = inode->i_mapping;
3143 struct page *page;
3144 u64 cur = start;
3145 unsigned long nr_pages;
3146 const u32 sectorsize = btrfs_sb(inode->i_sb)->sectorsize;
3147 struct btrfs_bio_ctrl bio_ctrl = {
3148 .extent_locked = 1,
3149 .sync_io = 1,
3150 };
3151 struct writeback_control wbc_writepages = {
3152 .sync_mode = WB_SYNC_ALL,
3153 .range_start = start,
3154 .range_end = end + 1,
3155 /* We're called from an async helper function */
3156 .punt_to_cgroup = 1,
3157 .no_cgroup_owner = 1,
3158 };
3159
3160 ASSERT(IS_ALIGNED(start, sectorsize) && IS_ALIGNED(end + 1, sectorsize));
3161 nr_pages = (round_up(end, PAGE_SIZE) - round_down(start, PAGE_SIZE)) >>
3162 PAGE_SHIFT;
3163 wbc_writepages.nr_to_write = nr_pages * 2;
3164
3165 wbc_attach_fdatawrite_inode(&wbc_writepages, inode);
3166 while (cur <= end) {
3167 u64 cur_end = min(round_down(cur, PAGE_SIZE) + PAGE_SIZE - 1, end);
3168
3169 page = find_get_page(mapping, cur >> PAGE_SHIFT);
3170 /*
3171 * All pages in the range are locked since
3172 * btrfs_run_delalloc_range(), thus there is no way to clear
3173 * the page dirty flag.
3174 */
3175 ASSERT(PageLocked(page));
3176 ASSERT(PageDirty(page));
3177 clear_page_dirty_for_io(page);
3178 ret = __extent_writepage(page, &wbc_writepages, &bio_ctrl);
3179 ASSERT(ret <= 0);
3180 if (ret < 0) {
3181 found_error = true;
3182 first_error = ret;
3183 }
3184 put_page(page);
3185 cur = cur_end + 1;
3186 }
3187
3188 submit_write_bio(&bio_ctrl, found_error ? ret : 0);
3189
3190 wbc_detach_inode(&wbc_writepages);
3191 if (found_error)
3192 return first_error;
3193 return ret;
3194}
3195
3196int extent_writepages(struct address_space *mapping,
3197 struct writeback_control *wbc)
3198{
3199 struct inode *inode = mapping->host;
3200 int ret = 0;
3201 struct btrfs_bio_ctrl bio_ctrl = {
3202 .extent_locked = 0,
3203 .sync_io = (wbc->sync_mode == WB_SYNC_ALL),
3204 };
3205
3206 /*
3207 * Allow only a single thread to do the reloc work in zoned mode to
3208 * protect the write pointer updates.
3209 */
3210 btrfs_zoned_data_reloc_lock(BTRFS_I(inode));
3211 ret = extent_write_cache_pages(mapping, wbc, &bio_ctrl);
3212 submit_write_bio(&bio_ctrl, ret);
3213 btrfs_zoned_data_reloc_unlock(BTRFS_I(inode));
3214 return ret;
3215}
3216
3217void extent_readahead(struct readahead_control *rac)
3218{
3219 struct btrfs_bio_ctrl bio_ctrl = { 0 };
3220 struct page *pagepool[16];
3221 struct extent_map *em_cached = NULL;
3222 u64 prev_em_start = (u64)-1;
3223 int nr;
3224
3225 while ((nr = readahead_page_batch(rac, pagepool))) {
3226 u64 contig_start = readahead_pos(rac);
3227 u64 contig_end = contig_start + readahead_batch_length(rac) - 1;
3228
3229 contiguous_readpages(pagepool, nr, contig_start, contig_end,
3230 &em_cached, &bio_ctrl, &prev_em_start);
3231 }
3232
3233 if (em_cached)
3234 free_extent_map(em_cached);
3235 submit_one_bio(&bio_ctrl);
3236}
3237
3238/*
3239 * basic invalidate_folio code, this waits on any locked or writeback
3240 * ranges corresponding to the folio, and then deletes any extent state
3241 * records from the tree
3242 */
3243int extent_invalidate_folio(struct extent_io_tree *tree,
3244 struct folio *folio, size_t offset)
3245{
3246 struct extent_state *cached_state = NULL;
3247 u64 start = folio_pos(folio);
3248 u64 end = start + folio_size(folio) - 1;
3249 size_t blocksize = folio->mapping->host->i_sb->s_blocksize;
3250
3251 /* This function is only called for the btree inode */
3252 ASSERT(tree->owner == IO_TREE_BTREE_INODE_IO);
3253
3254 start += ALIGN(offset, blocksize);
3255 if (start > end)
3256 return 0;
3257
3258 lock_extent(tree, start, end, &cached_state);
3259 folio_wait_writeback(folio);
3260
3261 /*
3262 * Currently for btree io tree, only EXTENT_LOCKED is utilized,
3263 * so here we only need to unlock the extent range to free any
3264 * existing extent state.
3265 */
3266 unlock_extent(tree, start, end, &cached_state);
3267 return 0;
3268}
3269
3270/*
3271 * a helper for release_folio, this tests for areas of the page that
3272 * are locked or under IO and drops the related state bits if it is safe
3273 * to drop the page.
3274 */
3275static int try_release_extent_state(struct extent_io_tree *tree,
3276 struct page *page, gfp_t mask)
3277{
3278 u64 start = page_offset(page);
3279 u64 end = start + PAGE_SIZE - 1;
3280 int ret = 1;
3281
3282 if (test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL)) {
3283 ret = 0;
3284 } else {
3285 u32 clear_bits = ~(EXTENT_LOCKED | EXTENT_NODATASUM |
3286 EXTENT_DELALLOC_NEW | EXTENT_CTLBITS);
3287
3288 /*
3289 * At this point we can safely clear everything except the
3290 * locked bit, the nodatasum bit and the delalloc new bit.
3291 * The delalloc new bit will be cleared by ordered extent
3292 * completion.
3293 */
3294 ret = __clear_extent_bit(tree, start, end, clear_bits, NULL,
3295 mask, NULL);
3296
3297 /* if clear_extent_bit failed for enomem reasons,
3298 * we can't allow the release to continue.
3299 */
3300 if (ret < 0)
3301 ret = 0;
3302 else
3303 ret = 1;
3304 }
3305 return ret;
3306}
3307
3308/*
3309 * a helper for release_folio. As long as there are no locked extents
3310 * in the range corresponding to the page, both state records and extent
3311 * map records are removed
3312 */
3313int try_release_extent_mapping(struct page *page, gfp_t mask)
3314{
3315 struct extent_map *em;
3316 u64 start = page_offset(page);
3317 u64 end = start + PAGE_SIZE - 1;
3318 struct btrfs_inode *btrfs_inode = BTRFS_I(page->mapping->host);
3319 struct extent_io_tree *tree = &btrfs_inode->io_tree;
3320 struct extent_map_tree *map = &btrfs_inode->extent_tree;
3321
3322 if (gfpflags_allow_blocking(mask) &&
3323 page->mapping->host->i_size > SZ_16M) {
3324 u64 len;
3325 while (start <= end) {
3326 struct btrfs_fs_info *fs_info;
3327 u64 cur_gen;
3328
3329 len = end - start + 1;
3330 write_lock(&map->lock);
3331 em = lookup_extent_mapping(map, start, len);
3332 if (!em) {
3333 write_unlock(&map->lock);
3334 break;
3335 }
3336 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
3337 em->start != start) {
3338 write_unlock(&map->lock);
3339 free_extent_map(em);
3340 break;
3341 }
3342 if (test_range_bit(tree, em->start,
3343 extent_map_end(em) - 1,
3344 EXTENT_LOCKED, 0, NULL))
3345 goto next;
3346 /*
3347 * If it's not in the list of modified extents, used
3348 * by a fast fsync, we can remove it. If it's being
3349 * logged we can safely remove it since fsync took an
3350 * extra reference on the em.
3351 */
3352 if (list_empty(&em->list) ||
3353 test_bit(EXTENT_FLAG_LOGGING, &em->flags))
3354 goto remove_em;
3355 /*
3356 * If it's in the list of modified extents, remove it
3357 * only if its generation is older then the current one,
3358 * in which case we don't need it for a fast fsync.
3359 * Otherwise don't remove it, we could be racing with an
3360 * ongoing fast fsync that could miss the new extent.
3361 */
3362 fs_info = btrfs_inode->root->fs_info;
3363 spin_lock(&fs_info->trans_lock);
3364 cur_gen = fs_info->generation;
3365 spin_unlock(&fs_info->trans_lock);
3366 if (em->generation >= cur_gen)
3367 goto next;
3368remove_em:
3369 /*
3370 * We only remove extent maps that are not in the list of
3371 * modified extents or that are in the list but with a
3372 * generation lower then the current generation, so there
3373 * is no need to set the full fsync flag on the inode (it
3374 * hurts the fsync performance for workloads with a data
3375 * size that exceeds or is close to the system's memory).
3376 */
3377 remove_extent_mapping(map, em);
3378 /* once for the rb tree */
3379 free_extent_map(em);
3380next:
3381 start = extent_map_end(em);
3382 write_unlock(&map->lock);
3383
3384 /* once for us */
3385 free_extent_map(em);
3386
3387 cond_resched(); /* Allow large-extent preemption. */
3388 }
3389 }
3390 return try_release_extent_state(tree, page, mask);
3391}
3392
3393/*
3394 * To cache previous fiemap extent
3395 *
3396 * Will be used for merging fiemap extent
3397 */
3398struct fiemap_cache {
3399 u64 offset;
3400 u64 phys;
3401 u64 len;
3402 u32 flags;
3403 bool cached;
3404};
3405
3406/*
3407 * Helper to submit fiemap extent.
3408 *
3409 * Will try to merge current fiemap extent specified by @offset, @phys,
3410 * @len and @flags with cached one.
3411 * And only when we fails to merge, cached one will be submitted as
3412 * fiemap extent.
3413 *
3414 * Return value is the same as fiemap_fill_next_extent().
3415 */
3416static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
3417 struct fiemap_cache *cache,
3418 u64 offset, u64 phys, u64 len, u32 flags)
3419{
3420 int ret = 0;
3421
3422 /* Set at the end of extent_fiemap(). */
3423 ASSERT((flags & FIEMAP_EXTENT_LAST) == 0);
3424
3425 if (!cache->cached)
3426 goto assign;
3427
3428 /*
3429 * Sanity check, extent_fiemap() should have ensured that new
3430 * fiemap extent won't overlap with cached one.
3431 * Not recoverable.
3432 *
3433 * NOTE: Physical address can overlap, due to compression
3434 */
3435 if (cache->offset + cache->len > offset) {
3436 WARN_ON(1);
3437 return -EINVAL;
3438 }
3439
3440 /*
3441 * Only merges fiemap extents if
3442 * 1) Their logical addresses are continuous
3443 *
3444 * 2) Their physical addresses are continuous
3445 * So truly compressed (physical size smaller than logical size)
3446 * extents won't get merged with each other
3447 *
3448 * 3) Share same flags
3449 */
3450 if (cache->offset + cache->len == offset &&
3451 cache->phys + cache->len == phys &&
3452 cache->flags == flags) {
3453 cache->len += len;
3454 return 0;
3455 }
3456
3457 /* Not mergeable, need to submit cached one */
3458 ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
3459 cache->len, cache->flags);
3460 cache->cached = false;
3461 if (ret)
3462 return ret;
3463assign:
3464 cache->cached = true;
3465 cache->offset = offset;
3466 cache->phys = phys;
3467 cache->len = len;
3468 cache->flags = flags;
3469
3470 return 0;
3471}
3472
3473/*
3474 * Emit last fiemap cache
3475 *
3476 * The last fiemap cache may still be cached in the following case:
3477 * 0 4k 8k
3478 * |<- Fiemap range ->|
3479 * |<------------ First extent ----------->|
3480 *
3481 * In this case, the first extent range will be cached but not emitted.
3482 * So we must emit it before ending extent_fiemap().
3483 */
3484static int emit_last_fiemap_cache(struct fiemap_extent_info *fieinfo,
3485 struct fiemap_cache *cache)
3486{
3487 int ret;
3488
3489 if (!cache->cached)
3490 return 0;
3491
3492 ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
3493 cache->len, cache->flags);
3494 cache->cached = false;
3495 if (ret > 0)
3496 ret = 0;
3497 return ret;
3498}
3499
3500static int fiemap_next_leaf_item(struct btrfs_inode *inode, struct btrfs_path *path)
3501{
3502 struct extent_buffer *clone;
3503 struct btrfs_key key;
3504 int slot;
3505 int ret;
3506
3507 path->slots[0]++;
3508 if (path->slots[0] < btrfs_header_nritems(path->nodes[0]))
3509 return 0;
3510
3511 ret = btrfs_next_leaf(inode->root, path);
3512 if (ret != 0)
3513 return ret;
3514
3515 /*
3516 * Don't bother with cloning if there are no more file extent items for
3517 * our inode.
3518 */
3519 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3520 if (key.objectid != btrfs_ino(inode) || key.type != BTRFS_EXTENT_DATA_KEY)
3521 return 1;
3522
3523 /* See the comment at fiemap_search_slot() about why we clone. */
3524 clone = btrfs_clone_extent_buffer(path->nodes[0]);
3525 if (!clone)
3526 return -ENOMEM;
3527
3528 slot = path->slots[0];
3529 btrfs_release_path(path);
3530 path->nodes[0] = clone;
3531 path->slots[0] = slot;
3532
3533 return 0;
3534}
3535
3536/*
3537 * Search for the first file extent item that starts at a given file offset or
3538 * the one that starts immediately before that offset.
3539 * Returns: 0 on success, < 0 on error, 1 if not found.
3540 */
3541static int fiemap_search_slot(struct btrfs_inode *inode, struct btrfs_path *path,
3542 u64 file_offset)
3543{
3544 const u64 ino = btrfs_ino(inode);
3545 struct btrfs_root *root = inode->root;
3546 struct extent_buffer *clone;
3547 struct btrfs_key key;
3548 int slot;
3549 int ret;
3550
3551 key.objectid = ino;
3552 key.type = BTRFS_EXTENT_DATA_KEY;
3553 key.offset = file_offset;
3554
3555 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3556 if (ret < 0)
3557 return ret;
3558
3559 if (ret > 0 && path->slots[0] > 0) {
3560 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1);
3561 if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY)
3562 path->slots[0]--;
3563 }
3564
3565 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
3566 ret = btrfs_next_leaf(root, path);
3567 if (ret != 0)
3568 return ret;
3569
3570 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3571 if (key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY)
3572 return 1;
3573 }
3574
3575 /*
3576 * We clone the leaf and use it during fiemap. This is because while
3577 * using the leaf we do expensive things like checking if an extent is
3578 * shared, which can take a long time. In order to prevent blocking
3579 * other tasks for too long, we use a clone of the leaf. We have locked
3580 * the file range in the inode's io tree, so we know none of our file
3581 * extent items can change. This way we avoid blocking other tasks that
3582 * want to insert items for other inodes in the same leaf or b+tree
3583 * rebalance operations (triggered for example when someone is trying
3584 * to push items into this leaf when trying to insert an item in a
3585 * neighbour leaf).
3586 * We also need the private clone because holding a read lock on an
3587 * extent buffer of the subvolume's b+tree will make lockdep unhappy
3588 * when we call fiemap_fill_next_extent(), because that may cause a page
3589 * fault when filling the user space buffer with fiemap data.
3590 */
3591 clone = btrfs_clone_extent_buffer(path->nodes[0]);
3592 if (!clone)
3593 return -ENOMEM;
3594
3595 slot = path->slots[0];
3596 btrfs_release_path(path);
3597 path->nodes[0] = clone;
3598 path->slots[0] = slot;
3599
3600 return 0;
3601}
3602
3603/*
3604 * Process a range which is a hole or a prealloc extent in the inode's subvolume
3605 * btree. If @disk_bytenr is 0, we are dealing with a hole, otherwise a prealloc
3606 * extent. The end offset (@end) is inclusive.
3607 */
3608static int fiemap_process_hole(struct btrfs_inode *inode,
3609 struct fiemap_extent_info *fieinfo,
3610 struct fiemap_cache *cache,
3611 struct extent_state **delalloc_cached_state,
3612 struct btrfs_backref_share_check_ctx *backref_ctx,
3613 u64 disk_bytenr, u64 extent_offset,
3614 u64 extent_gen,
3615 u64 start, u64 end)
3616{
3617 const u64 i_size = i_size_read(&inode->vfs_inode);
3618 u64 cur_offset = start;
3619 u64 last_delalloc_end = 0;
3620 u32 prealloc_flags = FIEMAP_EXTENT_UNWRITTEN;
3621 bool checked_extent_shared = false;
3622 int ret;
3623
3624 /*
3625 * There can be no delalloc past i_size, so don't waste time looking for
3626 * it beyond i_size.
3627 */
3628 while (cur_offset < end && cur_offset < i_size) {
3629 u64 delalloc_start;
3630 u64 delalloc_end;
3631 u64 prealloc_start;
3632 u64 prealloc_len = 0;
3633 bool delalloc;
3634
3635 delalloc = btrfs_find_delalloc_in_range(inode, cur_offset, end,
3636 delalloc_cached_state,
3637 &delalloc_start,
3638 &delalloc_end);
3639 if (!delalloc)
3640 break;
3641
3642 /*
3643 * If this is a prealloc extent we have to report every section
3644 * of it that has no delalloc.
3645 */
3646 if (disk_bytenr != 0) {
3647 if (last_delalloc_end == 0) {
3648 prealloc_start = start;
3649 prealloc_len = delalloc_start - start;
3650 } else {
3651 prealloc_start = last_delalloc_end + 1;
3652 prealloc_len = delalloc_start - prealloc_start;
3653 }
3654 }
3655
3656 if (prealloc_len > 0) {
3657 if (!checked_extent_shared && fieinfo->fi_extents_max) {
3658 ret = btrfs_is_data_extent_shared(inode,
3659 disk_bytenr,
3660 extent_gen,
3661 backref_ctx);
3662 if (ret < 0)
3663 return ret;
3664 else if (ret > 0)
3665 prealloc_flags |= FIEMAP_EXTENT_SHARED;
3666
3667 checked_extent_shared = true;
3668 }
3669 ret = emit_fiemap_extent(fieinfo, cache, prealloc_start,
3670 disk_bytenr + extent_offset,
3671 prealloc_len, prealloc_flags);
3672 if (ret)
3673 return ret;
3674 extent_offset += prealloc_len;
3675 }
3676
3677 ret = emit_fiemap_extent(fieinfo, cache, delalloc_start, 0,
3678 delalloc_end + 1 - delalloc_start,
3679 FIEMAP_EXTENT_DELALLOC |
3680 FIEMAP_EXTENT_UNKNOWN);
3681 if (ret)
3682 return ret;
3683
3684 last_delalloc_end = delalloc_end;
3685 cur_offset = delalloc_end + 1;
3686 extent_offset += cur_offset - delalloc_start;
3687 cond_resched();
3688 }
3689
3690 /*
3691 * Either we found no delalloc for the whole prealloc extent or we have
3692 * a prealloc extent that spans i_size or starts at or after i_size.
3693 */
3694 if (disk_bytenr != 0 && last_delalloc_end < end) {
3695 u64 prealloc_start;
3696 u64 prealloc_len;
3697
3698 if (last_delalloc_end == 0) {
3699 prealloc_start = start;
3700 prealloc_len = end + 1 - start;
3701 } else {
3702 prealloc_start = last_delalloc_end + 1;
3703 prealloc_len = end + 1 - prealloc_start;
3704 }
3705
3706 if (!checked_extent_shared && fieinfo->fi_extents_max) {
3707 ret = btrfs_is_data_extent_shared(inode,
3708 disk_bytenr,
3709 extent_gen,
3710 backref_ctx);
3711 if (ret < 0)
3712 return ret;
3713 else if (ret > 0)
3714 prealloc_flags |= FIEMAP_EXTENT_SHARED;
3715 }
3716 ret = emit_fiemap_extent(fieinfo, cache, prealloc_start,
3717 disk_bytenr + extent_offset,
3718 prealloc_len, prealloc_flags);
3719 if (ret)
3720 return ret;
3721 }
3722
3723 return 0;
3724}
3725
3726static int fiemap_find_last_extent_offset(struct btrfs_inode *inode,
3727 struct btrfs_path *path,
3728 u64 *last_extent_end_ret)
3729{
3730 const u64 ino = btrfs_ino(inode);
3731 struct btrfs_root *root = inode->root;
3732 struct extent_buffer *leaf;
3733 struct btrfs_file_extent_item *ei;
3734 struct btrfs_key key;
3735 u64 disk_bytenr;
3736 int ret;
3737
3738 /*
3739 * Lookup the last file extent. We're not using i_size here because
3740 * there might be preallocation past i_size.
3741 */
3742 ret = btrfs_lookup_file_extent(NULL, root, path, ino, (u64)-1, 0);
3743 /* There can't be a file extent item at offset (u64)-1 */
3744 ASSERT(ret != 0);
3745 if (ret < 0)
3746 return ret;
3747
3748 /*
3749 * For a non-existing key, btrfs_search_slot() always leaves us at a
3750 * slot > 0, except if the btree is empty, which is impossible because
3751 * at least it has the inode item for this inode and all the items for
3752 * the root inode 256.
3753 */
3754 ASSERT(path->slots[0] > 0);
3755 path->slots[0]--;
3756 leaf = path->nodes[0];
3757 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3758 if (key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY) {
3759 /* No file extent items in the subvolume tree. */
3760 *last_extent_end_ret = 0;
3761 return 0;
3762 }
3763
3764 /*
3765 * For an inline extent, the disk_bytenr is where inline data starts at,
3766 * so first check if we have an inline extent item before checking if we
3767 * have an implicit hole (disk_bytenr == 0).
3768 */
3769 ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item);
3770 if (btrfs_file_extent_type(leaf, ei) == BTRFS_FILE_EXTENT_INLINE) {
3771 *last_extent_end_ret = btrfs_file_extent_end(path);
3772 return 0;
3773 }
3774
3775 /*
3776 * Find the last file extent item that is not a hole (when NO_HOLES is
3777 * not enabled). This should take at most 2 iterations in the worst
3778 * case: we have one hole file extent item at slot 0 of a leaf and
3779 * another hole file extent item as the last item in the previous leaf.
3780 * This is because we merge file extent items that represent holes.
3781 */
3782 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, ei);
3783 while (disk_bytenr == 0) {
3784 ret = btrfs_previous_item(root, path, ino, BTRFS_EXTENT_DATA_KEY);
3785 if (ret < 0) {
3786 return ret;
3787 } else if (ret > 0) {
3788 /* No file extent items that are not holes. */
3789 *last_extent_end_ret = 0;
3790 return 0;
3791 }
3792 leaf = path->nodes[0];
3793 ei = btrfs_item_ptr(leaf, path->slots[0],
3794 struct btrfs_file_extent_item);
3795 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, ei);
3796 }
3797
3798 *last_extent_end_ret = btrfs_file_extent_end(path);
3799 return 0;
3800}
3801
3802int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
3803 u64 start, u64 len)
3804{
3805 const u64 ino = btrfs_ino(inode);
3806 struct extent_state *cached_state = NULL;
3807 struct extent_state *delalloc_cached_state = NULL;
3808 struct btrfs_path *path;
3809 struct fiemap_cache cache = { 0 };
3810 struct btrfs_backref_share_check_ctx *backref_ctx;
3811 u64 last_extent_end;
3812 u64 prev_extent_end;
3813 u64 lockstart;
3814 u64 lockend;
3815 bool stopped = false;
3816 int ret;
3817
3818 backref_ctx = btrfs_alloc_backref_share_check_ctx();
3819 path = btrfs_alloc_path();
3820 if (!backref_ctx || !path) {
3821 ret = -ENOMEM;
3822 goto out;
3823 }
3824
3825 lockstart = round_down(start, inode->root->fs_info->sectorsize);
3826 lockend = round_up(start + len, inode->root->fs_info->sectorsize);
3827 prev_extent_end = lockstart;
3828
3829 btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
3830 lock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
3831
3832 ret = fiemap_find_last_extent_offset(inode, path, &last_extent_end);
3833 if (ret < 0)
3834 goto out_unlock;
3835 btrfs_release_path(path);
3836
3837 path->reada = READA_FORWARD;
3838 ret = fiemap_search_slot(inode, path, lockstart);
3839 if (ret < 0) {
3840 goto out_unlock;
3841 } else if (ret > 0) {
3842 /*
3843 * No file extent item found, but we may have delalloc between
3844 * the current offset and i_size. So check for that.
3845 */
3846 ret = 0;
3847 goto check_eof_delalloc;
3848 }
3849
3850 while (prev_extent_end < lockend) {
3851 struct extent_buffer *leaf = path->nodes[0];
3852 struct btrfs_file_extent_item *ei;
3853 struct btrfs_key key;
3854 u64 extent_end;
3855 u64 extent_len;
3856 u64 extent_offset = 0;
3857 u64 extent_gen;
3858 u64 disk_bytenr = 0;
3859 u64 flags = 0;
3860 int extent_type;
3861 u8 compression;
3862
3863 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3864 if (key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY)
3865 break;
3866
3867 extent_end = btrfs_file_extent_end(path);
3868
3869 /*
3870 * The first iteration can leave us at an extent item that ends
3871 * before our range's start. Move to the next item.
3872 */
3873 if (extent_end <= lockstart)
3874 goto next_item;
3875
3876 backref_ctx->curr_leaf_bytenr = leaf->start;
3877
3878 /* We have in implicit hole (NO_HOLES feature enabled). */
3879 if (prev_extent_end < key.offset) {
3880 const u64 range_end = min(key.offset, lockend) - 1;
3881
3882 ret = fiemap_process_hole(inode, fieinfo, &cache,
3883 &delalloc_cached_state,
3884 backref_ctx, 0, 0, 0,
3885 prev_extent_end, range_end);
3886 if (ret < 0) {
3887 goto out_unlock;
3888 } else if (ret > 0) {
3889 /* fiemap_fill_next_extent() told us to stop. */
3890 stopped = true;
3891 break;
3892 }
3893
3894 /* We've reached the end of the fiemap range, stop. */
3895 if (key.offset >= lockend) {
3896 stopped = true;
3897 break;
3898 }
3899 }
3900
3901 extent_len = extent_end - key.offset;
3902 ei = btrfs_item_ptr(leaf, path->slots[0],
3903 struct btrfs_file_extent_item);
3904 compression = btrfs_file_extent_compression(leaf, ei);
3905 extent_type = btrfs_file_extent_type(leaf, ei);
3906 extent_gen = btrfs_file_extent_generation(leaf, ei);
3907
3908 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3909 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, ei);
3910 if (compression == BTRFS_COMPRESS_NONE)
3911 extent_offset = btrfs_file_extent_offset(leaf, ei);
3912 }
3913
3914 if (compression != BTRFS_COMPRESS_NONE)
3915 flags |= FIEMAP_EXTENT_ENCODED;
3916
3917 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3918 flags |= FIEMAP_EXTENT_DATA_INLINE;
3919 flags |= FIEMAP_EXTENT_NOT_ALIGNED;
3920 ret = emit_fiemap_extent(fieinfo, &cache, key.offset, 0,
3921 extent_len, flags);
3922 } else if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
3923 ret = fiemap_process_hole(inode, fieinfo, &cache,
3924 &delalloc_cached_state,
3925 backref_ctx,
3926 disk_bytenr, extent_offset,
3927 extent_gen, key.offset,
3928 extent_end - 1);
3929 } else if (disk_bytenr == 0) {
3930 /* We have an explicit hole. */
3931 ret = fiemap_process_hole(inode, fieinfo, &cache,
3932 &delalloc_cached_state,
3933 backref_ctx, 0, 0, 0,
3934 key.offset, extent_end - 1);
3935 } else {
3936 /* We have a regular extent. */
3937 if (fieinfo->fi_extents_max) {
3938 ret = btrfs_is_data_extent_shared(inode,
3939 disk_bytenr,
3940 extent_gen,
3941 backref_ctx);
3942 if (ret < 0)
3943 goto out_unlock;
3944 else if (ret > 0)
3945 flags |= FIEMAP_EXTENT_SHARED;
3946 }
3947
3948 ret = emit_fiemap_extent(fieinfo, &cache, key.offset,
3949 disk_bytenr + extent_offset,
3950 extent_len, flags);
3951 }
3952
3953 if (ret < 0) {
3954 goto out_unlock;
3955 } else if (ret > 0) {
3956 /* fiemap_fill_next_extent() told us to stop. */
3957 stopped = true;
3958 break;
3959 }
3960
3961 prev_extent_end = extent_end;
3962next_item:
3963 if (fatal_signal_pending(current)) {
3964 ret = -EINTR;
3965 goto out_unlock;
3966 }
3967
3968 ret = fiemap_next_leaf_item(inode, path);
3969 if (ret < 0) {
3970 goto out_unlock;
3971 } else if (ret > 0) {
3972 /* No more file extent items for this inode. */
3973 break;
3974 }
3975 cond_resched();
3976 }
3977
3978check_eof_delalloc:
3979 /*
3980 * Release (and free) the path before emitting any final entries to
3981 * fiemap_fill_next_extent() to keep lockdep happy. This is because
3982 * once we find no more file extent items exist, we may have a
3983 * non-cloned leaf, and fiemap_fill_next_extent() can trigger page
3984 * faults when copying data to the user space buffer.
3985 */
3986 btrfs_free_path(path);
3987 path = NULL;
3988
3989 if (!stopped && prev_extent_end < lockend) {
3990 ret = fiemap_process_hole(inode, fieinfo, &cache,
3991 &delalloc_cached_state, backref_ctx,
3992 0, 0, 0, prev_extent_end, lockend - 1);
3993 if (ret < 0)
3994 goto out_unlock;
3995 prev_extent_end = lockend;
3996 }
3997
3998 if (cache.cached && cache.offset + cache.len >= last_extent_end) {
3999 const u64 i_size = i_size_read(&inode->vfs_inode);
4000
4001 if (prev_extent_end < i_size) {
4002 u64 delalloc_start;
4003 u64 delalloc_end;
4004 bool delalloc;
4005
4006 delalloc = btrfs_find_delalloc_in_range(inode,
4007 prev_extent_end,
4008 i_size - 1,
4009 &delalloc_cached_state,
4010 &delalloc_start,
4011 &delalloc_end);
4012 if (!delalloc)
4013 cache.flags |= FIEMAP_EXTENT_LAST;
4014 } else {
4015 cache.flags |= FIEMAP_EXTENT_LAST;
4016 }
4017 }
4018
4019 ret = emit_last_fiemap_cache(fieinfo, &cache);
4020
4021out_unlock:
4022 unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
4023 btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
4024out:
4025 free_extent_state(delalloc_cached_state);
4026 btrfs_free_backref_share_ctx(backref_ctx);
4027 btrfs_free_path(path);
4028 return ret;
4029}
4030
4031static void __free_extent_buffer(struct extent_buffer *eb)
4032{
4033 kmem_cache_free(extent_buffer_cache, eb);
4034}
4035
4036int extent_buffer_under_io(const struct extent_buffer *eb)
4037{
4038 return (atomic_read(&eb->io_pages) ||
4039 test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
4040 test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4041}
4042
4043static bool page_range_has_eb(struct btrfs_fs_info *fs_info, struct page *page)
4044{
4045 struct btrfs_subpage *subpage;
4046
4047 lockdep_assert_held(&page->mapping->private_lock);
4048
4049 if (PagePrivate(page)) {
4050 subpage = (struct btrfs_subpage *)page->private;
4051 if (atomic_read(&subpage->eb_refs))
4052 return true;
4053 /*
4054 * Even there is no eb refs here, we may still have
4055 * end_page_read() call relying on page::private.
4056 */
4057 if (atomic_read(&subpage->readers))
4058 return true;
4059 }
4060 return false;
4061}
4062
4063static void detach_extent_buffer_page(struct extent_buffer *eb, struct page *page)
4064{
4065 struct btrfs_fs_info *fs_info = eb->fs_info;
4066 const bool mapped = !test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
4067
4068 /*
4069 * For mapped eb, we're going to change the page private, which should
4070 * be done under the private_lock.
4071 */
4072 if (mapped)
4073 spin_lock(&page->mapping->private_lock);
4074
4075 if (!PagePrivate(page)) {
4076 if (mapped)
4077 spin_unlock(&page->mapping->private_lock);
4078 return;
4079 }
4080
4081 if (fs_info->nodesize >= PAGE_SIZE) {
4082 /*
4083 * We do this since we'll remove the pages after we've
4084 * removed the eb from the radix tree, so we could race
4085 * and have this page now attached to the new eb. So
4086 * only clear page_private if it's still connected to
4087 * this eb.
4088 */
4089 if (PagePrivate(page) &&
4090 page->private == (unsigned long)eb) {
4091 BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4092 BUG_ON(PageDirty(page));
4093 BUG_ON(PageWriteback(page));
4094 /*
4095 * We need to make sure we haven't be attached
4096 * to a new eb.
4097 */
4098 detach_page_private(page);
4099 }
4100 if (mapped)
4101 spin_unlock(&page->mapping->private_lock);
4102 return;
4103 }
4104
4105 /*
4106 * For subpage, we can have dummy eb with page private. In this case,
4107 * we can directly detach the private as such page is only attached to
4108 * one dummy eb, no sharing.
4109 */
4110 if (!mapped) {
4111 btrfs_detach_subpage(fs_info, page);
4112 return;
4113 }
4114
4115 btrfs_page_dec_eb_refs(fs_info, page);
4116
4117 /*
4118 * We can only detach the page private if there are no other ebs in the
4119 * page range and no unfinished IO.
4120 */
4121 if (!page_range_has_eb(fs_info, page))
4122 btrfs_detach_subpage(fs_info, page);
4123
4124 spin_unlock(&page->mapping->private_lock);
4125}
4126
4127/* Release all pages attached to the extent buffer */
4128static void btrfs_release_extent_buffer_pages(struct extent_buffer *eb)
4129{
4130 int i;
4131 int num_pages;
4132
4133 ASSERT(!extent_buffer_under_io(eb));
4134
4135 num_pages = num_extent_pages(eb);
4136 for (i = 0; i < num_pages; i++) {
4137 struct page *page = eb->pages[i];
4138
4139 if (!page)
4140 continue;
4141
4142 detach_extent_buffer_page(eb, page);
4143
4144 /* One for when we allocated the page */
4145 put_page(page);
4146 }
4147}
4148
4149/*
4150 * Helper for releasing the extent buffer.
4151 */
4152static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
4153{
4154 btrfs_release_extent_buffer_pages(eb);
4155 btrfs_leak_debug_del_eb(eb);
4156 __free_extent_buffer(eb);
4157}
4158
4159static struct extent_buffer *
4160__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
4161 unsigned long len)
4162{
4163 struct extent_buffer *eb = NULL;
4164
4165 eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
4166 eb->start = start;
4167 eb->len = len;
4168 eb->fs_info = fs_info;
4169 init_rwsem(&eb->lock);
4170
4171 btrfs_leak_debug_add_eb(eb);
4172 INIT_LIST_HEAD(&eb->release_list);
4173
4174 spin_lock_init(&eb->refs_lock);
4175 atomic_set(&eb->refs, 1);
4176 atomic_set(&eb->io_pages, 0);
4177
4178 ASSERT(len <= BTRFS_MAX_METADATA_BLOCKSIZE);
4179
4180 return eb;
4181}
4182
4183struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src)
4184{
4185 int i;
4186 struct extent_buffer *new;
4187 int num_pages = num_extent_pages(src);
4188 int ret;
4189
4190 new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
4191 if (new == NULL)
4192 return NULL;
4193
4194 /*
4195 * Set UNMAPPED before calling btrfs_release_extent_buffer(), as
4196 * btrfs_release_extent_buffer() have different behavior for
4197 * UNMAPPED subpage extent buffer.
4198 */
4199 set_bit(EXTENT_BUFFER_UNMAPPED, &new->bflags);
4200
4201 ret = btrfs_alloc_page_array(num_pages, new->pages);
4202 if (ret) {
4203 btrfs_release_extent_buffer(new);
4204 return NULL;
4205 }
4206
4207 for (i = 0; i < num_pages; i++) {
4208 int ret;
4209 struct page *p = new->pages[i];
4210
4211 ret = attach_extent_buffer_page(new, p, NULL);
4212 if (ret < 0) {
4213 btrfs_release_extent_buffer(new);
4214 return NULL;
4215 }
4216 WARN_ON(PageDirty(p));
4217 copy_page(page_address(p), page_address(src->pages[i]));
4218 }
4219 set_extent_buffer_uptodate(new);
4220
4221 return new;
4222}
4223
4224struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4225 u64 start, unsigned long len)
4226{
4227 struct extent_buffer *eb;
4228 int num_pages;
4229 int i;
4230 int ret;
4231
4232 eb = __alloc_extent_buffer(fs_info, start, len);
4233 if (!eb)
4234 return NULL;
4235
4236 num_pages = num_extent_pages(eb);
4237 ret = btrfs_alloc_page_array(num_pages, eb->pages);
4238 if (ret)
4239 goto err;
4240
4241 for (i = 0; i < num_pages; i++) {
4242 struct page *p = eb->pages[i];
4243
4244 ret = attach_extent_buffer_page(eb, p, NULL);
4245 if (ret < 0)
4246 goto err;
4247 }
4248
4249 set_extent_buffer_uptodate(eb);
4250 btrfs_set_header_nritems(eb, 0);
4251 set_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
4252
4253 return eb;
4254err:
4255 for (i = 0; i < num_pages; i++) {
4256 if (eb->pages[i]) {
4257 detach_extent_buffer_page(eb, eb->pages[i]);
4258 __free_page(eb->pages[i]);
4259 }
4260 }
4261 __free_extent_buffer(eb);
4262 return NULL;
4263}
4264
4265struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4266 u64 start)
4267{
4268 return __alloc_dummy_extent_buffer(fs_info, start, fs_info->nodesize);
4269}
4270
4271static void check_buffer_tree_ref(struct extent_buffer *eb)
4272{
4273 int refs;
4274 /*
4275 * The TREE_REF bit is first set when the extent_buffer is added
4276 * to the radix tree. It is also reset, if unset, when a new reference
4277 * is created by find_extent_buffer.
4278 *
4279 * It is only cleared in two cases: freeing the last non-tree
4280 * reference to the extent_buffer when its STALE bit is set or
4281 * calling release_folio when the tree reference is the only reference.
4282 *
4283 * In both cases, care is taken to ensure that the extent_buffer's
4284 * pages are not under io. However, release_folio can be concurrently
4285 * called with creating new references, which is prone to race
4286 * conditions between the calls to check_buffer_tree_ref in those
4287 * codepaths and clearing TREE_REF in try_release_extent_buffer.
4288 *
4289 * The actual lifetime of the extent_buffer in the radix tree is
4290 * adequately protected by the refcount, but the TREE_REF bit and
4291 * its corresponding reference are not. To protect against this
4292 * class of races, we call check_buffer_tree_ref from the codepaths
4293 * which trigger io after they set eb->io_pages. Note that once io is
4294 * initiated, TREE_REF can no longer be cleared, so that is the
4295 * moment at which any such race is best fixed.
4296 */
4297 refs = atomic_read(&eb->refs);
4298 if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4299 return;
4300
4301 spin_lock(&eb->refs_lock);
4302 if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4303 atomic_inc(&eb->refs);
4304 spin_unlock(&eb->refs_lock);
4305}
4306
4307static void mark_extent_buffer_accessed(struct extent_buffer *eb,
4308 struct page *accessed)
4309{
4310 int num_pages, i;
4311
4312 check_buffer_tree_ref(eb);
4313
4314 num_pages = num_extent_pages(eb);
4315 for (i = 0; i < num_pages; i++) {
4316 struct page *p = eb->pages[i];
4317
4318 if (p != accessed)
4319 mark_page_accessed(p);
4320 }
4321}
4322
4323struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
4324 u64 start)
4325{
4326 struct extent_buffer *eb;
4327
4328 eb = find_extent_buffer_nolock(fs_info, start);
4329 if (!eb)
4330 return NULL;
4331 /*
4332 * Lock our eb's refs_lock to avoid races with free_extent_buffer().
4333 * When we get our eb it might be flagged with EXTENT_BUFFER_STALE and
4334 * another task running free_extent_buffer() might have seen that flag
4335 * set, eb->refs == 2, that the buffer isn't under IO (dirty and
4336 * writeback flags not set) and it's still in the tree (flag
4337 * EXTENT_BUFFER_TREE_REF set), therefore being in the process of
4338 * decrementing the extent buffer's reference count twice. So here we
4339 * could race and increment the eb's reference count, clear its stale
4340 * flag, mark it as dirty and drop our reference before the other task
4341 * finishes executing free_extent_buffer, which would later result in
4342 * an attempt to free an extent buffer that is dirty.
4343 */
4344 if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
4345 spin_lock(&eb->refs_lock);
4346 spin_unlock(&eb->refs_lock);
4347 }
4348 mark_extent_buffer_accessed(eb, NULL);
4349 return eb;
4350}
4351
4352#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4353struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
4354 u64 start)
4355{
4356 struct extent_buffer *eb, *exists = NULL;
4357 int ret;
4358
4359 eb = find_extent_buffer(fs_info, start);
4360 if (eb)
4361 return eb;
4362 eb = alloc_dummy_extent_buffer(fs_info, start);
4363 if (!eb)
4364 return ERR_PTR(-ENOMEM);
4365 eb->fs_info = fs_info;
4366again:
4367 ret = radix_tree_preload(GFP_NOFS);
4368 if (ret) {
4369 exists = ERR_PTR(ret);
4370 goto free_eb;
4371 }
4372 spin_lock(&fs_info->buffer_lock);
4373 ret = radix_tree_insert(&fs_info->buffer_radix,
4374 start >> fs_info->sectorsize_bits, eb);
4375 spin_unlock(&fs_info->buffer_lock);
4376 radix_tree_preload_end();
4377 if (ret == -EEXIST) {
4378 exists = find_extent_buffer(fs_info, start);
4379 if (exists)
4380 goto free_eb;
4381 else
4382 goto again;
4383 }
4384 check_buffer_tree_ref(eb);
4385 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4386
4387 return eb;
4388free_eb:
4389 btrfs_release_extent_buffer(eb);
4390 return exists;
4391}
4392#endif
4393
4394static struct extent_buffer *grab_extent_buffer(
4395 struct btrfs_fs_info *fs_info, struct page *page)
4396{
4397 struct extent_buffer *exists;
4398
4399 /*
4400 * For subpage case, we completely rely on radix tree to ensure we
4401 * don't try to insert two ebs for the same bytenr. So here we always
4402 * return NULL and just continue.
4403 */
4404 if (fs_info->nodesize < PAGE_SIZE)
4405 return NULL;
4406
4407 /* Page not yet attached to an extent buffer */
4408 if (!PagePrivate(page))
4409 return NULL;
4410
4411 /*
4412 * We could have already allocated an eb for this page and attached one
4413 * so lets see if we can get a ref on the existing eb, and if we can we
4414 * know it's good and we can just return that one, else we know we can
4415 * just overwrite page->private.
4416 */
4417 exists = (struct extent_buffer *)page->private;
4418 if (atomic_inc_not_zero(&exists->refs))
4419 return exists;
4420
4421 WARN_ON(PageDirty(page));
4422 detach_page_private(page);
4423 return NULL;
4424}
4425
4426static int check_eb_alignment(struct btrfs_fs_info *fs_info, u64 start)
4427{
4428 if (!IS_ALIGNED(start, fs_info->sectorsize)) {
4429 btrfs_err(fs_info, "bad tree block start %llu", start);
4430 return -EINVAL;
4431 }
4432
4433 if (fs_info->nodesize < PAGE_SIZE &&
4434 offset_in_page(start) + fs_info->nodesize > PAGE_SIZE) {
4435 btrfs_err(fs_info,
4436 "tree block crosses page boundary, start %llu nodesize %u",
4437 start, fs_info->nodesize);
4438 return -EINVAL;
4439 }
4440 if (fs_info->nodesize >= PAGE_SIZE &&
4441 !PAGE_ALIGNED(start)) {
4442 btrfs_err(fs_info,
4443 "tree block is not page aligned, start %llu nodesize %u",
4444 start, fs_info->nodesize);
4445 return -EINVAL;
4446 }
4447 return 0;
4448}
4449
4450struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4451 u64 start, u64 owner_root, int level)
4452{
4453 unsigned long len = fs_info->nodesize;
4454 int num_pages;
4455 int i;
4456 unsigned long index = start >> PAGE_SHIFT;
4457 struct extent_buffer *eb;
4458 struct extent_buffer *exists = NULL;
4459 struct page *p;
4460 struct address_space *mapping = fs_info->btree_inode->i_mapping;
4461 u64 lockdep_owner = owner_root;
4462 int uptodate = 1;
4463 int ret;
4464
4465 if (check_eb_alignment(fs_info, start))
4466 return ERR_PTR(-EINVAL);
4467
4468#if BITS_PER_LONG == 32
4469 if (start >= MAX_LFS_FILESIZE) {
4470 btrfs_err_rl(fs_info,
4471 "extent buffer %llu is beyond 32bit page cache limit", start);
4472 btrfs_err_32bit_limit(fs_info);
4473 return ERR_PTR(-EOVERFLOW);
4474 }
4475 if (start >= BTRFS_32BIT_EARLY_WARN_THRESHOLD)
4476 btrfs_warn_32bit_limit(fs_info);
4477#endif
4478
4479 eb = find_extent_buffer(fs_info, start);
4480 if (eb)
4481 return eb;
4482
4483 eb = __alloc_extent_buffer(fs_info, start, len);
4484 if (!eb)
4485 return ERR_PTR(-ENOMEM);
4486
4487 /*
4488 * The reloc trees are just snapshots, so we need them to appear to be
4489 * just like any other fs tree WRT lockdep.
4490 */
4491 if (lockdep_owner == BTRFS_TREE_RELOC_OBJECTID)
4492 lockdep_owner = BTRFS_FS_TREE_OBJECTID;
4493
4494 btrfs_set_buffer_lockdep_class(lockdep_owner, eb, level);
4495
4496 num_pages = num_extent_pages(eb);
4497 for (i = 0; i < num_pages; i++, index++) {
4498 struct btrfs_subpage *prealloc = NULL;
4499
4500 p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
4501 if (!p) {
4502 exists = ERR_PTR(-ENOMEM);
4503 goto free_eb;
4504 }
4505
4506 /*
4507 * Preallocate page->private for subpage case, so that we won't
4508 * allocate memory with private_lock hold. The memory will be
4509 * freed by attach_extent_buffer_page() or freed manually if
4510 * we exit earlier.
4511 *
4512 * Although we have ensured one subpage eb can only have one
4513 * page, but it may change in the future for 16K page size
4514 * support, so we still preallocate the memory in the loop.
4515 */
4516 if (fs_info->nodesize < PAGE_SIZE) {
4517 prealloc = btrfs_alloc_subpage(fs_info, BTRFS_SUBPAGE_METADATA);
4518 if (IS_ERR(prealloc)) {
4519 ret = PTR_ERR(prealloc);
4520 unlock_page(p);
4521 put_page(p);
4522 exists = ERR_PTR(ret);
4523 goto free_eb;
4524 }
4525 }
4526
4527 spin_lock(&mapping->private_lock);
4528 exists = grab_extent_buffer(fs_info, p);
4529 if (exists) {
4530 spin_unlock(&mapping->private_lock);
4531 unlock_page(p);
4532 put_page(p);
4533 mark_extent_buffer_accessed(exists, p);
4534 btrfs_free_subpage(prealloc);
4535 goto free_eb;
4536 }
4537 /* Should not fail, as we have preallocated the memory */
4538 ret = attach_extent_buffer_page(eb, p, prealloc);
4539 ASSERT(!ret);
4540 /*
4541 * To inform we have extra eb under allocation, so that
4542 * detach_extent_buffer_page() won't release the page private
4543 * when the eb hasn't yet been inserted into radix tree.
4544 *
4545 * The ref will be decreased when the eb released the page, in
4546 * detach_extent_buffer_page().
4547 * Thus needs no special handling in error path.
4548 */
4549 btrfs_page_inc_eb_refs(fs_info, p);
4550 spin_unlock(&mapping->private_lock);
4551
4552 WARN_ON(btrfs_page_test_dirty(fs_info, p, eb->start, eb->len));
4553 eb->pages[i] = p;
4554 if (!PageUptodate(p))
4555 uptodate = 0;
4556
4557 /*
4558 * We can't unlock the pages just yet since the extent buffer
4559 * hasn't been properly inserted in the radix tree, this
4560 * opens a race with btree_release_folio which can free a page
4561 * while we are still filling in all pages for the buffer and
4562 * we could crash.
4563 */
4564 }
4565 if (uptodate)
4566 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4567again:
4568 ret = radix_tree_preload(GFP_NOFS);
4569 if (ret) {
4570 exists = ERR_PTR(ret);
4571 goto free_eb;
4572 }
4573
4574 spin_lock(&fs_info->buffer_lock);
4575 ret = radix_tree_insert(&fs_info->buffer_radix,
4576 start >> fs_info->sectorsize_bits, eb);
4577 spin_unlock(&fs_info->buffer_lock);
4578 radix_tree_preload_end();
4579 if (ret == -EEXIST) {
4580 exists = find_extent_buffer(fs_info, start);
4581 if (exists)
4582 goto free_eb;
4583 else
4584 goto again;
4585 }
4586 /* add one reference for the tree */
4587 check_buffer_tree_ref(eb);
4588 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4589
4590 /*
4591 * Now it's safe to unlock the pages because any calls to
4592 * btree_release_folio will correctly detect that a page belongs to a
4593 * live buffer and won't free them prematurely.
4594 */
4595 for (i = 0; i < num_pages; i++)
4596 unlock_page(eb->pages[i]);
4597 return eb;
4598
4599free_eb:
4600 WARN_ON(!atomic_dec_and_test(&eb->refs));
4601 for (i = 0; i < num_pages; i++) {
4602 if (eb->pages[i])
4603 unlock_page(eb->pages[i]);
4604 }
4605
4606 btrfs_release_extent_buffer(eb);
4607 return exists;
4608}
4609
4610static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
4611{
4612 struct extent_buffer *eb =
4613 container_of(head, struct extent_buffer, rcu_head);
4614
4615 __free_extent_buffer(eb);
4616}
4617
4618static int release_extent_buffer(struct extent_buffer *eb)
4619 __releases(&eb->refs_lock)
4620{
4621 lockdep_assert_held(&eb->refs_lock);
4622
4623 WARN_ON(atomic_read(&eb->refs) == 0);
4624 if (atomic_dec_and_test(&eb->refs)) {
4625 if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
4626 struct btrfs_fs_info *fs_info = eb->fs_info;
4627
4628 spin_unlock(&eb->refs_lock);
4629
4630 spin_lock(&fs_info->buffer_lock);
4631 radix_tree_delete(&fs_info->buffer_radix,
4632 eb->start >> fs_info->sectorsize_bits);
4633 spin_unlock(&fs_info->buffer_lock);
4634 } else {
4635 spin_unlock(&eb->refs_lock);
4636 }
4637
4638 btrfs_leak_debug_del_eb(eb);
4639 /* Should be safe to release our pages at this point */
4640 btrfs_release_extent_buffer_pages(eb);
4641#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4642 if (unlikely(test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags))) {
4643 __free_extent_buffer(eb);
4644 return 1;
4645 }
4646#endif
4647 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
4648 return 1;
4649 }
4650 spin_unlock(&eb->refs_lock);
4651
4652 return 0;
4653}
4654
4655void free_extent_buffer(struct extent_buffer *eb)
4656{
4657 int refs;
4658 if (!eb)
4659 return;
4660
4661 refs = atomic_read(&eb->refs);
4662 while (1) {
4663 if ((!test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) && refs <= 3)
4664 || (test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) &&
4665 refs == 1))
4666 break;
4667 if (atomic_try_cmpxchg(&eb->refs, &refs, refs - 1))
4668 return;
4669 }
4670
4671 spin_lock(&eb->refs_lock);
4672 if (atomic_read(&eb->refs) == 2 &&
4673 test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
4674 !extent_buffer_under_io(eb) &&
4675 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4676 atomic_dec(&eb->refs);
4677
4678 /*
4679 * I know this is terrible, but it's temporary until we stop tracking
4680 * the uptodate bits and such for the extent buffers.
4681 */
4682 release_extent_buffer(eb);
4683}
4684
4685void free_extent_buffer_stale(struct extent_buffer *eb)
4686{
4687 if (!eb)
4688 return;
4689
4690 spin_lock(&eb->refs_lock);
4691 set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
4692
4693 if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
4694 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4695 atomic_dec(&eb->refs);
4696 release_extent_buffer(eb);
4697}
4698
4699static void btree_clear_page_dirty(struct page *page)
4700{
4701 ASSERT(PageDirty(page));
4702 ASSERT(PageLocked(page));
4703 clear_page_dirty_for_io(page);
4704 xa_lock_irq(&page->mapping->i_pages);
4705 if (!PageDirty(page))
4706 __xa_clear_mark(&page->mapping->i_pages,
4707 page_index(page), PAGECACHE_TAG_DIRTY);
4708 xa_unlock_irq(&page->mapping->i_pages);
4709}
4710
4711static void clear_subpage_extent_buffer_dirty(const struct extent_buffer *eb)
4712{
4713 struct btrfs_fs_info *fs_info = eb->fs_info;
4714 struct page *page = eb->pages[0];
4715 bool last;
4716
4717 /* btree_clear_page_dirty() needs page locked */
4718 lock_page(page);
4719 last = btrfs_subpage_clear_and_test_dirty(fs_info, page, eb->start,
4720 eb->len);
4721 if (last)
4722 btree_clear_page_dirty(page);
4723 unlock_page(page);
4724 WARN_ON(atomic_read(&eb->refs) == 0);
4725}
4726
4727void clear_extent_buffer_dirty(const struct extent_buffer *eb)
4728{
4729 int i;
4730 int num_pages;
4731 struct page *page;
4732
4733 if (eb->fs_info->nodesize < PAGE_SIZE)
4734 return clear_subpage_extent_buffer_dirty(eb);
4735
4736 num_pages = num_extent_pages(eb);
4737
4738 for (i = 0; i < num_pages; i++) {
4739 page = eb->pages[i];
4740 if (!PageDirty(page))
4741 continue;
4742 lock_page(page);
4743 btree_clear_page_dirty(page);
4744 ClearPageError(page);
4745 unlock_page(page);
4746 }
4747 WARN_ON(atomic_read(&eb->refs) == 0);
4748}
4749
4750bool set_extent_buffer_dirty(struct extent_buffer *eb)
4751{
4752 int i;
4753 int num_pages;
4754 bool was_dirty;
4755
4756 check_buffer_tree_ref(eb);
4757
4758 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
4759
4760 num_pages = num_extent_pages(eb);
4761 WARN_ON(atomic_read(&eb->refs) == 0);
4762 WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
4763
4764 if (!was_dirty) {
4765 bool subpage = eb->fs_info->nodesize < PAGE_SIZE;
4766
4767 /*
4768 * For subpage case, we can have other extent buffers in the
4769 * same page, and in clear_subpage_extent_buffer_dirty() we
4770 * have to clear page dirty without subpage lock held.
4771 * This can cause race where our page gets dirty cleared after
4772 * we just set it.
4773 *
4774 * Thankfully, clear_subpage_extent_buffer_dirty() has locked
4775 * its page for other reasons, we can use page lock to prevent
4776 * the above race.
4777 */
4778 if (subpage)
4779 lock_page(eb->pages[0]);
4780 for (i = 0; i < num_pages; i++)
4781 btrfs_page_set_dirty(eb->fs_info, eb->pages[i],
4782 eb->start, eb->len);
4783 if (subpage)
4784 unlock_page(eb->pages[0]);
4785 }
4786#ifdef CONFIG_BTRFS_DEBUG
4787 for (i = 0; i < num_pages; i++)
4788 ASSERT(PageDirty(eb->pages[i]));
4789#endif
4790
4791 return was_dirty;
4792}
4793
4794void clear_extent_buffer_uptodate(struct extent_buffer *eb)
4795{
4796 struct btrfs_fs_info *fs_info = eb->fs_info;
4797 struct page *page;
4798 int num_pages;
4799 int i;
4800
4801 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4802 num_pages = num_extent_pages(eb);
4803 for (i = 0; i < num_pages; i++) {
4804 page = eb->pages[i];
4805 if (!page)
4806 continue;
4807
4808 /*
4809 * This is special handling for metadata subpage, as regular
4810 * btrfs_is_subpage() can not handle cloned/dummy metadata.
4811 */
4812 if (fs_info->nodesize >= PAGE_SIZE)
4813 ClearPageUptodate(page);
4814 else
4815 btrfs_subpage_clear_uptodate(fs_info, page, eb->start,
4816 eb->len);
4817 }
4818}
4819
4820void set_extent_buffer_uptodate(struct extent_buffer *eb)
4821{
4822 struct btrfs_fs_info *fs_info = eb->fs_info;
4823 struct page *page;
4824 int num_pages;
4825 int i;
4826
4827 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4828 num_pages = num_extent_pages(eb);
4829 for (i = 0; i < num_pages; i++) {
4830 page = eb->pages[i];
4831
4832 /*
4833 * This is special handling for metadata subpage, as regular
4834 * btrfs_is_subpage() can not handle cloned/dummy metadata.
4835 */
4836 if (fs_info->nodesize >= PAGE_SIZE)
4837 SetPageUptodate(page);
4838 else
4839 btrfs_subpage_set_uptodate(fs_info, page, eb->start,
4840 eb->len);
4841 }
4842}
4843
4844static int read_extent_buffer_subpage(struct extent_buffer *eb, int wait,
4845 int mirror_num,
4846 struct btrfs_tree_parent_check *check)
4847{
4848 struct btrfs_fs_info *fs_info = eb->fs_info;
4849 struct extent_io_tree *io_tree;
4850 struct page *page = eb->pages[0];
4851 struct extent_state *cached_state = NULL;
4852 struct btrfs_bio_ctrl bio_ctrl = {
4853 .mirror_num = mirror_num,
4854 .parent_check = check,
4855 };
4856 int ret = 0;
4857
4858 ASSERT(!test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags));
4859 ASSERT(PagePrivate(page));
4860 ASSERT(check);
4861 io_tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
4862
4863 if (wait == WAIT_NONE) {
4864 if (!try_lock_extent(io_tree, eb->start, eb->start + eb->len - 1,
4865 &cached_state))
4866 return -EAGAIN;
4867 } else {
4868 ret = lock_extent(io_tree, eb->start, eb->start + eb->len - 1,
4869 &cached_state);
4870 if (ret < 0)
4871 return ret;
4872 }
4873
4874 ret = 0;
4875 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags) ||
4876 PageUptodate(page) ||
4877 btrfs_subpage_test_uptodate(fs_info, page, eb->start, eb->len)) {
4878 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4879 unlock_extent(io_tree, eb->start, eb->start + eb->len - 1,
4880 &cached_state);
4881 return ret;
4882 }
4883
4884 clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
4885 eb->read_mirror = 0;
4886 atomic_set(&eb->io_pages, 1);
4887 check_buffer_tree_ref(eb);
4888 bio_ctrl.end_io_func = end_bio_extent_readpage;
4889
4890 btrfs_subpage_clear_error(fs_info, page, eb->start, eb->len);
4891
4892 btrfs_subpage_start_reader(fs_info, page, eb->start, eb->len);
4893 ret = submit_extent_page(REQ_OP_READ, NULL, &bio_ctrl,
4894 eb->start, page, eb->len,
4895 eb->start - page_offset(page), 0, true);
4896 if (ret) {
4897 /*
4898 * In the endio function, if we hit something wrong we will
4899 * increase the io_pages, so here we need to decrease it for
4900 * error path.
4901 */
4902 atomic_dec(&eb->io_pages);
4903 }
4904 submit_one_bio(&bio_ctrl);
4905 if (ret || wait != WAIT_COMPLETE) {
4906 free_extent_state(cached_state);
4907 return ret;
4908 }
4909
4910 wait_extent_bit(io_tree, eb->start, eb->start + eb->len - 1,
4911 EXTENT_LOCKED, &cached_state);
4912 if (!test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
4913 ret = -EIO;
4914 return ret;
4915}
4916
4917int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
4918 struct btrfs_tree_parent_check *check)
4919{
4920 int i;
4921 struct page *page;
4922 int err;
4923 int ret = 0;
4924 int locked_pages = 0;
4925 int all_uptodate = 1;
4926 int num_pages;
4927 unsigned long num_reads = 0;
4928 struct btrfs_bio_ctrl bio_ctrl = {
4929 .mirror_num = mirror_num,
4930 .parent_check = check,
4931 };
4932
4933 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
4934 return 0;
4935
4936 /*
4937 * We could have had EXTENT_BUFFER_UPTODATE cleared by the write
4938 * operation, which could potentially still be in flight. In this case
4939 * we simply want to return an error.
4940 */
4941 if (unlikely(test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)))
4942 return -EIO;
4943
4944 if (eb->fs_info->nodesize < PAGE_SIZE)
4945 return read_extent_buffer_subpage(eb, wait, mirror_num, check);
4946
4947 num_pages = num_extent_pages(eb);
4948 for (i = 0; i < num_pages; i++) {
4949 page = eb->pages[i];
4950 if (wait == WAIT_NONE) {
4951 /*
4952 * WAIT_NONE is only utilized by readahead. If we can't
4953 * acquire the lock atomically it means either the eb
4954 * is being read out or under modification.
4955 * Either way the eb will be or has been cached,
4956 * readahead can exit safely.
4957 */
4958 if (!trylock_page(page))
4959 goto unlock_exit;
4960 } else {
4961 lock_page(page);
4962 }
4963 locked_pages++;
4964 }
4965 /*
4966 * We need to firstly lock all pages to make sure that
4967 * the uptodate bit of our pages won't be affected by
4968 * clear_extent_buffer_uptodate().
4969 */
4970 for (i = 0; i < num_pages; i++) {
4971 page = eb->pages[i];
4972 if (!PageUptodate(page)) {
4973 num_reads++;
4974 all_uptodate = 0;
4975 }
4976 }
4977
4978 if (all_uptodate) {
4979 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4980 goto unlock_exit;
4981 }
4982
4983 clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
4984 eb->read_mirror = 0;
4985 atomic_set(&eb->io_pages, num_reads);
4986 /*
4987 * It is possible for release_folio to clear the TREE_REF bit before we
4988 * set io_pages. See check_buffer_tree_ref for a more detailed comment.
4989 */
4990 check_buffer_tree_ref(eb);
4991 bio_ctrl.end_io_func = end_bio_extent_readpage;
4992 for (i = 0; i < num_pages; i++) {
4993 page = eb->pages[i];
4994
4995 if (!PageUptodate(page)) {
4996 if (ret) {
4997 atomic_dec(&eb->io_pages);
4998 unlock_page(page);
4999 continue;
5000 }
5001
5002 ClearPageError(page);
5003 err = submit_extent_page(REQ_OP_READ, NULL,
5004 &bio_ctrl, page_offset(page), page,
5005 PAGE_SIZE, 0, 0, false);
5006 if (err) {
5007 /*
5008 * We failed to submit the bio so it's the
5009 * caller's responsibility to perform cleanup
5010 * i.e unlock page/set error bit.
5011 */
5012 ret = err;
5013 SetPageError(page);
5014 unlock_page(page);
5015 atomic_dec(&eb->io_pages);
5016 }
5017 } else {
5018 unlock_page(page);
5019 }
5020 }
5021
5022 submit_one_bio(&bio_ctrl);
5023
5024 if (ret || wait != WAIT_COMPLETE)
5025 return ret;
5026
5027 for (i = 0; i < num_pages; i++) {
5028 page = eb->pages[i];
5029 wait_on_page_locked(page);
5030 if (!PageUptodate(page))
5031 ret = -EIO;
5032 }
5033
5034 return ret;
5035
5036unlock_exit:
5037 while (locked_pages > 0) {
5038 locked_pages--;
5039 page = eb->pages[locked_pages];
5040 unlock_page(page);
5041 }
5042 return ret;
5043}
5044
5045static bool report_eb_range(const struct extent_buffer *eb, unsigned long start,
5046 unsigned long len)
5047{
5048 btrfs_warn(eb->fs_info,
5049 "access to eb bytenr %llu len %lu out of range start %lu len %lu",
5050 eb->start, eb->len, start, len);
5051 WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
5052
5053 return true;
5054}
5055
5056/*
5057 * Check if the [start, start + len) range is valid before reading/writing
5058 * the eb.
5059 * NOTE: @start and @len are offset inside the eb, not logical address.
5060 *
5061 * Caller should not touch the dst/src memory if this function returns error.
5062 */
5063static inline int check_eb_range(const struct extent_buffer *eb,
5064 unsigned long start, unsigned long len)
5065{
5066 unsigned long offset;
5067
5068 /* start, start + len should not go beyond eb->len nor overflow */
5069 if (unlikely(check_add_overflow(start, len, &offset) || offset > eb->len))
5070 return report_eb_range(eb, start, len);
5071
5072 return false;
5073}
5074
5075void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
5076 unsigned long start, unsigned long len)
5077{
5078 size_t cur;
5079 size_t offset;
5080 struct page *page;
5081 char *kaddr;
5082 char *dst = (char *)dstv;
5083 unsigned long i = get_eb_page_index(start);
5084
5085 if (check_eb_range(eb, start, len))
5086 return;
5087
5088 offset = get_eb_offset_in_page(eb, start);
5089
5090 while (len > 0) {
5091 page = eb->pages[i];
5092
5093 cur = min(len, (PAGE_SIZE - offset));
5094 kaddr = page_address(page);
5095 memcpy(dst, kaddr + offset, cur);
5096
5097 dst += cur;
5098 len -= cur;
5099 offset = 0;
5100 i++;
5101 }
5102}
5103
5104int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
5105 void __user *dstv,
5106 unsigned long start, unsigned long len)
5107{
5108 size_t cur;
5109 size_t offset;
5110 struct page *page;
5111 char *kaddr;
5112 char __user *dst = (char __user *)dstv;
5113 unsigned long i = get_eb_page_index(start);
5114 int ret = 0;
5115
5116 WARN_ON(start > eb->len);
5117 WARN_ON(start + len > eb->start + eb->len);
5118
5119 offset = get_eb_offset_in_page(eb, start);
5120
5121 while (len > 0) {
5122 page = eb->pages[i];
5123
5124 cur = min(len, (PAGE_SIZE - offset));
5125 kaddr = page_address(page);
5126 if (copy_to_user_nofault(dst, kaddr + offset, cur)) {
5127 ret = -EFAULT;
5128 break;
5129 }
5130
5131 dst += cur;
5132 len -= cur;
5133 offset = 0;
5134 i++;
5135 }
5136
5137 return ret;
5138}
5139
5140int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
5141 unsigned long start, unsigned long len)
5142{
5143 size_t cur;
5144 size_t offset;
5145 struct page *page;
5146 char *kaddr;
5147 char *ptr = (char *)ptrv;
5148 unsigned long i = get_eb_page_index(start);
5149 int ret = 0;
5150
5151 if (check_eb_range(eb, start, len))
5152 return -EINVAL;
5153
5154 offset = get_eb_offset_in_page(eb, start);
5155
5156 while (len > 0) {
5157 page = eb->pages[i];
5158
5159 cur = min(len, (PAGE_SIZE - offset));
5160
5161 kaddr = page_address(page);
5162 ret = memcmp(ptr, kaddr + offset, cur);
5163 if (ret)
5164 break;
5165
5166 ptr += cur;
5167 len -= cur;
5168 offset = 0;
5169 i++;
5170 }
5171 return ret;
5172}
5173
5174/*
5175 * Check that the extent buffer is uptodate.
5176 *
5177 * For regular sector size == PAGE_SIZE case, check if @page is uptodate.
5178 * For subpage case, check if the range covered by the eb has EXTENT_UPTODATE.
5179 */
5180static void assert_eb_page_uptodate(const struct extent_buffer *eb,
5181 struct page *page)
5182{
5183 struct btrfs_fs_info *fs_info = eb->fs_info;
5184
5185 /*
5186 * If we are using the commit root we could potentially clear a page
5187 * Uptodate while we're using the extent buffer that we've previously
5188 * looked up. We don't want to complain in this case, as the page was
5189 * valid before, we just didn't write it out. Instead we want to catch
5190 * the case where we didn't actually read the block properly, which
5191 * would have !PageUptodate && !PageError, as we clear PageError before
5192 * reading.
5193 */
5194 if (fs_info->nodesize < PAGE_SIZE) {
5195 bool uptodate, error;
5196
5197 uptodate = btrfs_subpage_test_uptodate(fs_info, page,
5198 eb->start, eb->len);
5199 error = btrfs_subpage_test_error(fs_info, page, eb->start, eb->len);
5200 WARN_ON(!uptodate && !error);
5201 } else {
5202 WARN_ON(!PageUptodate(page) && !PageError(page));
5203 }
5204}
5205
5206void write_extent_buffer_chunk_tree_uuid(const struct extent_buffer *eb,
5207 const void *srcv)
5208{
5209 char *kaddr;
5210
5211 assert_eb_page_uptodate(eb, eb->pages[0]);
5212 kaddr = page_address(eb->pages[0]) +
5213 get_eb_offset_in_page(eb, offsetof(struct btrfs_header,
5214 chunk_tree_uuid));
5215 memcpy(kaddr, srcv, BTRFS_FSID_SIZE);
5216}
5217
5218void write_extent_buffer_fsid(const struct extent_buffer *eb, const void *srcv)
5219{
5220 char *kaddr;
5221
5222 assert_eb_page_uptodate(eb, eb->pages[0]);
5223 kaddr = page_address(eb->pages[0]) +
5224 get_eb_offset_in_page(eb, offsetof(struct btrfs_header, fsid));
5225 memcpy(kaddr, srcv, BTRFS_FSID_SIZE);
5226}
5227
5228void write_extent_buffer(const struct extent_buffer *eb, const void *srcv,
5229 unsigned long start, unsigned long len)
5230{
5231 size_t cur;
5232 size_t offset;
5233 struct page *page;
5234 char *kaddr;
5235 char *src = (char *)srcv;
5236 unsigned long i = get_eb_page_index(start);
5237
5238 WARN_ON(test_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags));
5239
5240 if (check_eb_range(eb, start, len))
5241 return;
5242
5243 offset = get_eb_offset_in_page(eb, start);
5244
5245 while (len > 0) {
5246 page = eb->pages[i];
5247 assert_eb_page_uptodate(eb, page);
5248
5249 cur = min(len, PAGE_SIZE - offset);
5250 kaddr = page_address(page);
5251 memcpy(kaddr + offset, src, cur);
5252
5253 src += cur;
5254 len -= cur;
5255 offset = 0;
5256 i++;
5257 }
5258}
5259
5260void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
5261 unsigned long len)
5262{
5263 size_t cur;
5264 size_t offset;
5265 struct page *page;
5266 char *kaddr;
5267 unsigned long i = get_eb_page_index(start);
5268
5269 if (check_eb_range(eb, start, len))
5270 return;
5271
5272 offset = get_eb_offset_in_page(eb, start);
5273
5274 while (len > 0) {
5275 page = eb->pages[i];
5276 assert_eb_page_uptodate(eb, page);
5277
5278 cur = min(len, PAGE_SIZE - offset);
5279 kaddr = page_address(page);
5280 memset(kaddr + offset, 0, cur);
5281
5282 len -= cur;
5283 offset = 0;
5284 i++;
5285 }
5286}
5287
5288void copy_extent_buffer_full(const struct extent_buffer *dst,
5289 const struct extent_buffer *src)
5290{
5291 int i;
5292 int num_pages;
5293
5294 ASSERT(dst->len == src->len);
5295
5296 if (dst->fs_info->nodesize >= PAGE_SIZE) {
5297 num_pages = num_extent_pages(dst);
5298 for (i = 0; i < num_pages; i++)
5299 copy_page(page_address(dst->pages[i]),
5300 page_address(src->pages[i]));
5301 } else {
5302 size_t src_offset = get_eb_offset_in_page(src, 0);
5303 size_t dst_offset = get_eb_offset_in_page(dst, 0);
5304
5305 ASSERT(src->fs_info->nodesize < PAGE_SIZE);
5306 memcpy(page_address(dst->pages[0]) + dst_offset,
5307 page_address(src->pages[0]) + src_offset,
5308 src->len);
5309 }
5310}
5311
5312void copy_extent_buffer(const struct extent_buffer *dst,
5313 const struct extent_buffer *src,
5314 unsigned long dst_offset, unsigned long src_offset,
5315 unsigned long len)
5316{
5317 u64 dst_len = dst->len;
5318 size_t cur;
5319 size_t offset;
5320 struct page *page;
5321 char *kaddr;
5322 unsigned long i = get_eb_page_index(dst_offset);
5323
5324 if (check_eb_range(dst, dst_offset, len) ||
5325 check_eb_range(src, src_offset, len))
5326 return;
5327
5328 WARN_ON(src->len != dst_len);
5329
5330 offset = get_eb_offset_in_page(dst, dst_offset);
5331
5332 while (len > 0) {
5333 page = dst->pages[i];
5334 assert_eb_page_uptodate(dst, page);
5335
5336 cur = min(len, (unsigned long)(PAGE_SIZE - offset));
5337
5338 kaddr = page_address(page);
5339 read_extent_buffer(src, kaddr + offset, src_offset, cur);
5340
5341 src_offset += cur;
5342 len -= cur;
5343 offset = 0;
5344 i++;
5345 }
5346}
5347
5348/*
5349 * eb_bitmap_offset() - calculate the page and offset of the byte containing the
5350 * given bit number
5351 * @eb: the extent buffer
5352 * @start: offset of the bitmap item in the extent buffer
5353 * @nr: bit number
5354 * @page_index: return index of the page in the extent buffer that contains the
5355 * given bit number
5356 * @page_offset: return offset into the page given by page_index
5357 *
5358 * This helper hides the ugliness of finding the byte in an extent buffer which
5359 * contains a given bit.
5360 */
5361static inline void eb_bitmap_offset(const struct extent_buffer *eb,
5362 unsigned long start, unsigned long nr,
5363 unsigned long *page_index,
5364 size_t *page_offset)
5365{
5366 size_t byte_offset = BIT_BYTE(nr);
5367 size_t offset;
5368
5369 /*
5370 * The byte we want is the offset of the extent buffer + the offset of
5371 * the bitmap item in the extent buffer + the offset of the byte in the
5372 * bitmap item.
5373 */
5374 offset = start + offset_in_page(eb->start) + byte_offset;
5375
5376 *page_index = offset >> PAGE_SHIFT;
5377 *page_offset = offset_in_page(offset);
5378}
5379
5380/*
5381 * Determine whether a bit in a bitmap item is set.
5382 *
5383 * @eb: the extent buffer
5384 * @start: offset of the bitmap item in the extent buffer
5385 * @nr: bit number to test
5386 */
5387int extent_buffer_test_bit(const struct extent_buffer *eb, unsigned long start,
5388 unsigned long nr)
5389{
5390 u8 *kaddr;
5391 struct page *page;
5392 unsigned long i;
5393 size_t offset;
5394
5395 eb_bitmap_offset(eb, start, nr, &i, &offset);
5396 page = eb->pages[i];
5397 assert_eb_page_uptodate(eb, page);
5398 kaddr = page_address(page);
5399 return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
5400}
5401
5402/*
5403 * Set an area of a bitmap to 1.
5404 *
5405 * @eb: the extent buffer
5406 * @start: offset of the bitmap item in the extent buffer
5407 * @pos: bit number of the first bit
5408 * @len: number of bits to set
5409 */
5410void extent_buffer_bitmap_set(const struct extent_buffer *eb, unsigned long start,
5411 unsigned long pos, unsigned long len)
5412{
5413 u8 *kaddr;
5414 struct page *page;
5415 unsigned long i;
5416 size_t offset;
5417 const unsigned int size = pos + len;
5418 int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5419 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
5420
5421 eb_bitmap_offset(eb, start, pos, &i, &offset);
5422 page = eb->pages[i];
5423 assert_eb_page_uptodate(eb, page);
5424 kaddr = page_address(page);
5425
5426 while (len >= bits_to_set) {
5427 kaddr[offset] |= mask_to_set;
5428 len -= bits_to_set;
5429 bits_to_set = BITS_PER_BYTE;
5430 mask_to_set = ~0;
5431 if (++offset >= PAGE_SIZE && len > 0) {
5432 offset = 0;
5433 page = eb->pages[++i];
5434 assert_eb_page_uptodate(eb, page);
5435 kaddr = page_address(page);
5436 }
5437 }
5438 if (len) {
5439 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5440 kaddr[offset] |= mask_to_set;
5441 }
5442}
5443
5444
5445/*
5446 * Clear an area of a bitmap.
5447 *
5448 * @eb: the extent buffer
5449 * @start: offset of the bitmap item in the extent buffer
5450 * @pos: bit number of the first bit
5451 * @len: number of bits to clear
5452 */
5453void extent_buffer_bitmap_clear(const struct extent_buffer *eb,
5454 unsigned long start, unsigned long pos,
5455 unsigned long len)
5456{
5457 u8 *kaddr;
5458 struct page *page;
5459 unsigned long i;
5460 size_t offset;
5461 const unsigned int size = pos + len;
5462 int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5463 u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
5464
5465 eb_bitmap_offset(eb, start, pos, &i, &offset);
5466 page = eb->pages[i];
5467 assert_eb_page_uptodate(eb, page);
5468 kaddr = page_address(page);
5469
5470 while (len >= bits_to_clear) {
5471 kaddr[offset] &= ~mask_to_clear;
5472 len -= bits_to_clear;
5473 bits_to_clear = BITS_PER_BYTE;
5474 mask_to_clear = ~0;
5475 if (++offset >= PAGE_SIZE && len > 0) {
5476 offset = 0;
5477 page = eb->pages[++i];
5478 assert_eb_page_uptodate(eb, page);
5479 kaddr = page_address(page);
5480 }
5481 }
5482 if (len) {
5483 mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5484 kaddr[offset] &= ~mask_to_clear;
5485 }
5486}
5487
5488static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
5489{
5490 unsigned long distance = (src > dst) ? src - dst : dst - src;
5491 return distance < len;
5492}
5493
5494static void copy_pages(struct page *dst_page, struct page *src_page,
5495 unsigned long dst_off, unsigned long src_off,
5496 unsigned long len)
5497{
5498 char *dst_kaddr = page_address(dst_page);
5499 char *src_kaddr;
5500 int must_memmove = 0;
5501
5502 if (dst_page != src_page) {
5503 src_kaddr = page_address(src_page);
5504 } else {
5505 src_kaddr = dst_kaddr;
5506 if (areas_overlap(src_off, dst_off, len))
5507 must_memmove = 1;
5508 }
5509
5510 if (must_memmove)
5511 memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
5512 else
5513 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5514}
5515
5516void memcpy_extent_buffer(const struct extent_buffer *dst,
5517 unsigned long dst_offset, unsigned long src_offset,
5518 unsigned long len)
5519{
5520 size_t cur;
5521 size_t dst_off_in_page;
5522 size_t src_off_in_page;
5523 unsigned long dst_i;
5524 unsigned long src_i;
5525
5526 if (check_eb_range(dst, dst_offset, len) ||
5527 check_eb_range(dst, src_offset, len))
5528 return;
5529
5530 while (len > 0) {
5531 dst_off_in_page = get_eb_offset_in_page(dst, dst_offset);
5532 src_off_in_page = get_eb_offset_in_page(dst, src_offset);
5533
5534 dst_i = get_eb_page_index(dst_offset);
5535 src_i = get_eb_page_index(src_offset);
5536
5537 cur = min(len, (unsigned long)(PAGE_SIZE -
5538 src_off_in_page));
5539 cur = min_t(unsigned long, cur,
5540 (unsigned long)(PAGE_SIZE - dst_off_in_page));
5541
5542 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5543 dst_off_in_page, src_off_in_page, cur);
5544
5545 src_offset += cur;
5546 dst_offset += cur;
5547 len -= cur;
5548 }
5549}
5550
5551void memmove_extent_buffer(const struct extent_buffer *dst,
5552 unsigned long dst_offset, unsigned long src_offset,
5553 unsigned long len)
5554{
5555 size_t cur;
5556 size_t dst_off_in_page;
5557 size_t src_off_in_page;
5558 unsigned long dst_end = dst_offset + len - 1;
5559 unsigned long src_end = src_offset + len - 1;
5560 unsigned long dst_i;
5561 unsigned long src_i;
5562
5563 if (check_eb_range(dst, dst_offset, len) ||
5564 check_eb_range(dst, src_offset, len))
5565 return;
5566 if (dst_offset < src_offset) {
5567 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
5568 return;
5569 }
5570 while (len > 0) {
5571 dst_i = get_eb_page_index(dst_end);
5572 src_i = get_eb_page_index(src_end);
5573
5574 dst_off_in_page = get_eb_offset_in_page(dst, dst_end);
5575 src_off_in_page = get_eb_offset_in_page(dst, src_end);
5576
5577 cur = min_t(unsigned long, len, src_off_in_page + 1);
5578 cur = min(cur, dst_off_in_page + 1);
5579 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5580 dst_off_in_page - cur + 1,
5581 src_off_in_page - cur + 1, cur);
5582
5583 dst_end -= cur;
5584 src_end -= cur;
5585 len -= cur;
5586 }
5587}
5588
5589#define GANG_LOOKUP_SIZE 16
5590static struct extent_buffer *get_next_extent_buffer(
5591 struct btrfs_fs_info *fs_info, struct page *page, u64 bytenr)
5592{
5593 struct extent_buffer *gang[GANG_LOOKUP_SIZE];
5594 struct extent_buffer *found = NULL;
5595 u64 page_start = page_offset(page);
5596 u64 cur = page_start;
5597
5598 ASSERT(in_range(bytenr, page_start, PAGE_SIZE));
5599 lockdep_assert_held(&fs_info->buffer_lock);
5600
5601 while (cur < page_start + PAGE_SIZE) {
5602 int ret;
5603 int i;
5604
5605 ret = radix_tree_gang_lookup(&fs_info->buffer_radix,
5606 (void **)gang, cur >> fs_info->sectorsize_bits,
5607 min_t(unsigned int, GANG_LOOKUP_SIZE,
5608 PAGE_SIZE / fs_info->nodesize));
5609 if (ret == 0)
5610 goto out;
5611 for (i = 0; i < ret; i++) {
5612 /* Already beyond page end */
5613 if (gang[i]->start >= page_start + PAGE_SIZE)
5614 goto out;
5615 /* Found one */
5616 if (gang[i]->start >= bytenr) {
5617 found = gang[i];
5618 goto out;
5619 }
5620 }
5621 cur = gang[ret - 1]->start + gang[ret - 1]->len;
5622 }
5623out:
5624 return found;
5625}
5626
5627static int try_release_subpage_extent_buffer(struct page *page)
5628{
5629 struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
5630 u64 cur = page_offset(page);
5631 const u64 end = page_offset(page) + PAGE_SIZE;
5632 int ret;
5633
5634 while (cur < end) {
5635 struct extent_buffer *eb = NULL;
5636
5637 /*
5638 * Unlike try_release_extent_buffer() which uses page->private
5639 * to grab buffer, for subpage case we rely on radix tree, thus
5640 * we need to ensure radix tree consistency.
5641 *
5642 * We also want an atomic snapshot of the radix tree, thus go
5643 * with spinlock rather than RCU.
5644 */
5645 spin_lock(&fs_info->buffer_lock);
5646 eb = get_next_extent_buffer(fs_info, page, cur);
5647 if (!eb) {
5648 /* No more eb in the page range after or at cur */
5649 spin_unlock(&fs_info->buffer_lock);
5650 break;
5651 }
5652 cur = eb->start + eb->len;
5653
5654 /*
5655 * The same as try_release_extent_buffer(), to ensure the eb
5656 * won't disappear out from under us.
5657 */
5658 spin_lock(&eb->refs_lock);
5659 if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5660 spin_unlock(&eb->refs_lock);
5661 spin_unlock(&fs_info->buffer_lock);
5662 break;
5663 }
5664 spin_unlock(&fs_info->buffer_lock);
5665
5666 /*
5667 * If tree ref isn't set then we know the ref on this eb is a
5668 * real ref, so just return, this eb will likely be freed soon
5669 * anyway.
5670 */
5671 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
5672 spin_unlock(&eb->refs_lock);
5673 break;
5674 }
5675
5676 /*
5677 * Here we don't care about the return value, we will always
5678 * check the page private at the end. And
5679 * release_extent_buffer() will release the refs_lock.
5680 */
5681 release_extent_buffer(eb);
5682 }
5683 /*
5684 * Finally to check if we have cleared page private, as if we have
5685 * released all ebs in the page, the page private should be cleared now.
5686 */
5687 spin_lock(&page->mapping->private_lock);
5688 if (!PagePrivate(page))
5689 ret = 1;
5690 else
5691 ret = 0;
5692 spin_unlock(&page->mapping->private_lock);
5693 return ret;
5694
5695}
5696
5697int try_release_extent_buffer(struct page *page)
5698{
5699 struct extent_buffer *eb;
5700
5701 if (btrfs_sb(page->mapping->host->i_sb)->nodesize < PAGE_SIZE)
5702 return try_release_subpage_extent_buffer(page);
5703
5704 /*
5705 * We need to make sure nobody is changing page->private, as we rely on
5706 * page->private as the pointer to extent buffer.
5707 */
5708 spin_lock(&page->mapping->private_lock);
5709 if (!PagePrivate(page)) {
5710 spin_unlock(&page->mapping->private_lock);
5711 return 1;
5712 }
5713
5714 eb = (struct extent_buffer *)page->private;
5715 BUG_ON(!eb);
5716
5717 /*
5718 * This is a little awful but should be ok, we need to make sure that
5719 * the eb doesn't disappear out from under us while we're looking at
5720 * this page.
5721 */
5722 spin_lock(&eb->refs_lock);
5723 if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5724 spin_unlock(&eb->refs_lock);
5725 spin_unlock(&page->mapping->private_lock);
5726 return 0;
5727 }
5728 spin_unlock(&page->mapping->private_lock);
5729
5730 /*
5731 * If tree ref isn't set then we know the ref on this eb is a real ref,
5732 * so just return, this page will likely be freed soon anyway.
5733 */
5734 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
5735 spin_unlock(&eb->refs_lock);
5736 return 0;
5737 }
5738
5739 return release_extent_buffer(eb);
5740}
5741
5742/*
5743 * btrfs_readahead_tree_block - attempt to readahead a child block
5744 * @fs_info: the fs_info
5745 * @bytenr: bytenr to read
5746 * @owner_root: objectid of the root that owns this eb
5747 * @gen: generation for the uptodate check, can be 0
5748 * @level: level for the eb
5749 *
5750 * Attempt to readahead a tree block at @bytenr. If @gen is 0 then we do a
5751 * normal uptodate check of the eb, without checking the generation. If we have
5752 * to read the block we will not block on anything.
5753 */
5754void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
5755 u64 bytenr, u64 owner_root, u64 gen, int level)
5756{
5757 struct btrfs_tree_parent_check check = {
5758 .has_first_key = 0,
5759 .level = level,
5760 .transid = gen
5761 };
5762 struct extent_buffer *eb;
5763 int ret;
5764
5765 eb = btrfs_find_create_tree_block(fs_info, bytenr, owner_root, level);
5766 if (IS_ERR(eb))
5767 return;
5768
5769 if (btrfs_buffer_uptodate(eb, gen, 1)) {
5770 free_extent_buffer(eb);
5771 return;
5772 }
5773
5774 ret = read_extent_buffer_pages(eb, WAIT_NONE, 0, &check);
5775 if (ret < 0)
5776 free_extent_buffer_stale(eb);
5777 else
5778 free_extent_buffer(eb);
5779}
5780
5781/*
5782 * btrfs_readahead_node_child - readahead a node's child block
5783 * @node: parent node we're reading from
5784 * @slot: slot in the parent node for the child we want to read
5785 *
5786 * A helper for btrfs_readahead_tree_block, we simply read the bytenr pointed at
5787 * the slot in the node provided.
5788 */
5789void btrfs_readahead_node_child(struct extent_buffer *node, int slot)
5790{
5791 btrfs_readahead_tree_block(node->fs_info,
5792 btrfs_node_blockptr(node, slot),
5793 btrfs_header_owner(node),
5794 btrfs_node_ptr_generation(node, slot),
5795 btrfs_header_level(node) - 1);
5796}