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1 #include <linux/bitops.h>
2 #include <linux/slab.h>
3 #include <linux/bio.h>
4 #include <linux/mm.h>
5 #include <linux/pagemap.h>
6 #include <linux/page-flags.h>
7 #include <linux/spinlock.h>
8 #include <linux/blkdev.h>
9 #include <linux/swap.h>
10 #include <linux/writeback.h>
11 #include <linux/pagevec.h>
12 #include <linux/prefetch.h>
13 #include <linux/cleancache.h>
14 #include "extent_io.h"
15 #include "extent_map.h"
16 #include "ctree.h"
17 #include "btrfs_inode.h"
18 #include "volumes.h"
19 #include "check-integrity.h"
20 #include "locking.h"
21 #include "rcu-string.h"
22 #include "backref.h"
23 #include "transaction.h"
24
25 static struct kmem_cache *extent_state_cache;
26 static struct kmem_cache *extent_buffer_cache;
27 static struct bio_set *btrfs_bioset;
28
29 static inline bool extent_state_in_tree(const struct extent_state *state)
30 {
31 return !RB_EMPTY_NODE(&state->rb_node);
32 }
33
34 #ifdef CONFIG_BTRFS_DEBUG
35 static LIST_HEAD(buffers);
36 static LIST_HEAD(states);
37
38 static DEFINE_SPINLOCK(leak_lock);
39
40 static inline
41 void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
42 {
43 unsigned long flags;
44
45 spin_lock_irqsave(&leak_lock, flags);
46 list_add(new, head);
47 spin_unlock_irqrestore(&leak_lock, flags);
48 }
49
50 static inline
51 void btrfs_leak_debug_del(struct list_head *entry)
52 {
53 unsigned long flags;
54
55 spin_lock_irqsave(&leak_lock, flags);
56 list_del(entry);
57 spin_unlock_irqrestore(&leak_lock, flags);
58 }
59
60 static inline
61 void btrfs_leak_debug_check(void)
62 {
63 struct extent_state *state;
64 struct extent_buffer *eb;
65
66 while (!list_empty(&states)) {
67 state = list_entry(states.next, struct extent_state, leak_list);
68 pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
69 state->start, state->end, state->state,
70 extent_state_in_tree(state),
71 refcount_read(&state->refs));
72 list_del(&state->leak_list);
73 kmem_cache_free(extent_state_cache, state);
74 }
75
76 while (!list_empty(&buffers)) {
77 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
78 pr_err("BTRFS: buffer leak start %llu len %lu refs %d\n",
79 eb->start, eb->len, atomic_read(&eb->refs));
80 list_del(&eb->leak_list);
81 kmem_cache_free(extent_buffer_cache, eb);
82 }
83 }
84
85 #define btrfs_debug_check_extent_io_range(tree, start, end) \
86 __btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
87 static inline void __btrfs_debug_check_extent_io_range(const char *caller,
88 struct extent_io_tree *tree, u64 start, u64 end)
89 {
90 struct inode *inode;
91 u64 isize;
92
93 if (!tree->mapping)
94 return;
95
96 inode = tree->mapping->host;
97 isize = i_size_read(inode);
98 if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
99 btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
100 "%s: ino %llu isize %llu odd range [%llu,%llu]",
101 caller, btrfs_ino(BTRFS_I(inode)), isize, start, end);
102 }
103 }
104 #else
105 #define btrfs_leak_debug_add(new, head) do {} while (0)
106 #define btrfs_leak_debug_del(entry) do {} while (0)
107 #define btrfs_leak_debug_check() do {} while (0)
108 #define btrfs_debug_check_extent_io_range(c, s, e) do {} while (0)
109 #endif
110
111 #define BUFFER_LRU_MAX 64
112
113 struct tree_entry {
114 u64 start;
115 u64 end;
116 struct rb_node rb_node;
117 };
118
119 struct extent_page_data {
120 struct bio *bio;
121 struct extent_io_tree *tree;
122 get_extent_t *get_extent;
123 unsigned long bio_flags;
124
125 /* tells writepage not to lock the state bits for this range
126 * it still does the unlocking
127 */
128 unsigned int extent_locked:1;
129
130 /* tells the submit_bio code to use REQ_SYNC */
131 unsigned int sync_io:1;
132 };
133
134 static void add_extent_changeset(struct extent_state *state, unsigned bits,
135 struct extent_changeset *changeset,
136 int set)
137 {
138 int ret;
139
140 if (!changeset)
141 return;
142 if (set && (state->state & bits) == bits)
143 return;
144 if (!set && (state->state & bits) == 0)
145 return;
146 changeset->bytes_changed += state->end - state->start + 1;
147 ret = ulist_add(&changeset->range_changed, state->start, state->end,
148 GFP_ATOMIC);
149 /* ENOMEM */
150 BUG_ON(ret < 0);
151 }
152
153 static noinline void flush_write_bio(void *data);
154 static inline struct btrfs_fs_info *
155 tree_fs_info(struct extent_io_tree *tree)
156 {
157 if (!tree->mapping)
158 return NULL;
159 return btrfs_sb(tree->mapping->host->i_sb);
160 }
161
162 int __init extent_io_init(void)
163 {
164 extent_state_cache = kmem_cache_create("btrfs_extent_state",
165 sizeof(struct extent_state), 0,
166 SLAB_MEM_SPREAD, NULL);
167 if (!extent_state_cache)
168 return -ENOMEM;
169
170 extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
171 sizeof(struct extent_buffer), 0,
172 SLAB_MEM_SPREAD, NULL);
173 if (!extent_buffer_cache)
174 goto free_state_cache;
175
176 btrfs_bioset = bioset_create(BIO_POOL_SIZE,
177 offsetof(struct btrfs_io_bio, bio));
178 if (!btrfs_bioset)
179 goto free_buffer_cache;
180
181 if (bioset_integrity_create(btrfs_bioset, BIO_POOL_SIZE))
182 goto free_bioset;
183
184 return 0;
185
186 free_bioset:
187 bioset_free(btrfs_bioset);
188 btrfs_bioset = NULL;
189
190 free_buffer_cache:
191 kmem_cache_destroy(extent_buffer_cache);
192 extent_buffer_cache = NULL;
193
194 free_state_cache:
195 kmem_cache_destroy(extent_state_cache);
196 extent_state_cache = NULL;
197 return -ENOMEM;
198 }
199
200 void extent_io_exit(void)
201 {
202 btrfs_leak_debug_check();
203
204 /*
205 * Make sure all delayed rcu free are flushed before we
206 * destroy caches.
207 */
208 rcu_barrier();
209 kmem_cache_destroy(extent_state_cache);
210 kmem_cache_destroy(extent_buffer_cache);
211 if (btrfs_bioset)
212 bioset_free(btrfs_bioset);
213 }
214
215 void extent_io_tree_init(struct extent_io_tree *tree,
216 struct address_space *mapping)
217 {
218 tree->state = RB_ROOT;
219 tree->ops = NULL;
220 tree->dirty_bytes = 0;
221 spin_lock_init(&tree->lock);
222 tree->mapping = mapping;
223 }
224
225 static struct extent_state *alloc_extent_state(gfp_t mask)
226 {
227 struct extent_state *state;
228
229 /*
230 * The given mask might be not appropriate for the slab allocator,
231 * drop the unsupported bits
232 */
233 mask &= ~(__GFP_DMA32|__GFP_HIGHMEM);
234 state = kmem_cache_alloc(extent_state_cache, mask);
235 if (!state)
236 return state;
237 state->state = 0;
238 state->failrec = NULL;
239 RB_CLEAR_NODE(&state->rb_node);
240 btrfs_leak_debug_add(&state->leak_list, &states);
241 refcount_set(&state->refs, 1);
242 init_waitqueue_head(&state->wq);
243 trace_alloc_extent_state(state, mask, _RET_IP_);
244 return state;
245 }
246
247 void free_extent_state(struct extent_state *state)
248 {
249 if (!state)
250 return;
251 if (refcount_dec_and_test(&state->refs)) {
252 WARN_ON(extent_state_in_tree(state));
253 btrfs_leak_debug_del(&state->leak_list);
254 trace_free_extent_state(state, _RET_IP_);
255 kmem_cache_free(extent_state_cache, state);
256 }
257 }
258
259 static struct rb_node *tree_insert(struct rb_root *root,
260 struct rb_node *search_start,
261 u64 offset,
262 struct rb_node *node,
263 struct rb_node ***p_in,
264 struct rb_node **parent_in)
265 {
266 struct rb_node **p;
267 struct rb_node *parent = NULL;
268 struct tree_entry *entry;
269
270 if (p_in && parent_in) {
271 p = *p_in;
272 parent = *parent_in;
273 goto do_insert;
274 }
275
276 p = search_start ? &search_start : &root->rb_node;
277 while (*p) {
278 parent = *p;
279 entry = rb_entry(parent, struct tree_entry, rb_node);
280
281 if (offset < entry->start)
282 p = &(*p)->rb_left;
283 else if (offset > entry->end)
284 p = &(*p)->rb_right;
285 else
286 return parent;
287 }
288
289 do_insert:
290 rb_link_node(node, parent, p);
291 rb_insert_color(node, root);
292 return NULL;
293 }
294
295 static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
296 struct rb_node **prev_ret,
297 struct rb_node **next_ret,
298 struct rb_node ***p_ret,
299 struct rb_node **parent_ret)
300 {
301 struct rb_root *root = &tree->state;
302 struct rb_node **n = &root->rb_node;
303 struct rb_node *prev = NULL;
304 struct rb_node *orig_prev = NULL;
305 struct tree_entry *entry;
306 struct tree_entry *prev_entry = NULL;
307
308 while (*n) {
309 prev = *n;
310 entry = rb_entry(prev, struct tree_entry, rb_node);
311 prev_entry = entry;
312
313 if (offset < entry->start)
314 n = &(*n)->rb_left;
315 else if (offset > entry->end)
316 n = &(*n)->rb_right;
317 else
318 return *n;
319 }
320
321 if (p_ret)
322 *p_ret = n;
323 if (parent_ret)
324 *parent_ret = prev;
325
326 if (prev_ret) {
327 orig_prev = prev;
328 while (prev && offset > prev_entry->end) {
329 prev = rb_next(prev);
330 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
331 }
332 *prev_ret = prev;
333 prev = orig_prev;
334 }
335
336 if (next_ret) {
337 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
338 while (prev && offset < prev_entry->start) {
339 prev = rb_prev(prev);
340 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
341 }
342 *next_ret = prev;
343 }
344 return NULL;
345 }
346
347 static inline struct rb_node *
348 tree_search_for_insert(struct extent_io_tree *tree,
349 u64 offset,
350 struct rb_node ***p_ret,
351 struct rb_node **parent_ret)
352 {
353 struct rb_node *prev = NULL;
354 struct rb_node *ret;
355
356 ret = __etree_search(tree, offset, &prev, NULL, p_ret, parent_ret);
357 if (!ret)
358 return prev;
359 return ret;
360 }
361
362 static inline struct rb_node *tree_search(struct extent_io_tree *tree,
363 u64 offset)
364 {
365 return tree_search_for_insert(tree, offset, NULL, NULL);
366 }
367
368 static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
369 struct extent_state *other)
370 {
371 if (tree->ops && tree->ops->merge_extent_hook)
372 tree->ops->merge_extent_hook(tree->mapping->host, new,
373 other);
374 }
375
376 /*
377 * utility function to look for merge candidates inside a given range.
378 * Any extents with matching state are merged together into a single
379 * extent in the tree. Extents with EXTENT_IO in their state field
380 * are not merged because the end_io handlers need to be able to do
381 * operations on them without sleeping (or doing allocations/splits).
382 *
383 * This should be called with the tree lock held.
384 */
385 static void merge_state(struct extent_io_tree *tree,
386 struct extent_state *state)
387 {
388 struct extent_state *other;
389 struct rb_node *other_node;
390
391 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
392 return;
393
394 other_node = rb_prev(&state->rb_node);
395 if (other_node) {
396 other = rb_entry(other_node, struct extent_state, rb_node);
397 if (other->end == state->start - 1 &&
398 other->state == state->state) {
399 merge_cb(tree, state, other);
400 state->start = other->start;
401 rb_erase(&other->rb_node, &tree->state);
402 RB_CLEAR_NODE(&other->rb_node);
403 free_extent_state(other);
404 }
405 }
406 other_node = rb_next(&state->rb_node);
407 if (other_node) {
408 other = rb_entry(other_node, struct extent_state, rb_node);
409 if (other->start == state->end + 1 &&
410 other->state == state->state) {
411 merge_cb(tree, state, other);
412 state->end = other->end;
413 rb_erase(&other->rb_node, &tree->state);
414 RB_CLEAR_NODE(&other->rb_node);
415 free_extent_state(other);
416 }
417 }
418 }
419
420 static void set_state_cb(struct extent_io_tree *tree,
421 struct extent_state *state, unsigned *bits)
422 {
423 if (tree->ops && tree->ops->set_bit_hook)
424 tree->ops->set_bit_hook(tree->mapping->host, state, bits);
425 }
426
427 static void clear_state_cb(struct extent_io_tree *tree,
428 struct extent_state *state, unsigned *bits)
429 {
430 if (tree->ops && tree->ops->clear_bit_hook)
431 tree->ops->clear_bit_hook(BTRFS_I(tree->mapping->host),
432 state, bits);
433 }
434
435 static void set_state_bits(struct extent_io_tree *tree,
436 struct extent_state *state, unsigned *bits,
437 struct extent_changeset *changeset);
438
439 /*
440 * insert an extent_state struct into the tree. 'bits' are set on the
441 * struct before it is inserted.
442 *
443 * This may return -EEXIST if the extent is already there, in which case the
444 * state struct is freed.
445 *
446 * The tree lock is not taken internally. This is a utility function and
447 * probably isn't what you want to call (see set/clear_extent_bit).
448 */
449 static int insert_state(struct extent_io_tree *tree,
450 struct extent_state *state, u64 start, u64 end,
451 struct rb_node ***p,
452 struct rb_node **parent,
453 unsigned *bits, struct extent_changeset *changeset)
454 {
455 struct rb_node *node;
456
457 if (end < start)
458 WARN(1, KERN_ERR "BTRFS: end < start %llu %llu\n",
459 end, start);
460 state->start = start;
461 state->end = end;
462
463 set_state_bits(tree, state, bits, changeset);
464
465 node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
466 if (node) {
467 struct extent_state *found;
468 found = rb_entry(node, struct extent_state, rb_node);
469 pr_err("BTRFS: found node %llu %llu on insert of %llu %llu\n",
470 found->start, found->end, start, end);
471 return -EEXIST;
472 }
473 merge_state(tree, state);
474 return 0;
475 }
476
477 static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
478 u64 split)
479 {
480 if (tree->ops && tree->ops->split_extent_hook)
481 tree->ops->split_extent_hook(tree->mapping->host, orig, split);
482 }
483
484 /*
485 * split a given extent state struct in two, inserting the preallocated
486 * struct 'prealloc' as the newly created second half. 'split' indicates an
487 * offset inside 'orig' where it should be split.
488 *
489 * Before calling,
490 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
491 * are two extent state structs in the tree:
492 * prealloc: [orig->start, split - 1]
493 * orig: [ split, orig->end ]
494 *
495 * The tree locks are not taken by this function. They need to be held
496 * by the caller.
497 */
498 static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
499 struct extent_state *prealloc, u64 split)
500 {
501 struct rb_node *node;
502
503 split_cb(tree, orig, split);
504
505 prealloc->start = orig->start;
506 prealloc->end = split - 1;
507 prealloc->state = orig->state;
508 orig->start = split;
509
510 node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
511 &prealloc->rb_node, NULL, NULL);
512 if (node) {
513 free_extent_state(prealloc);
514 return -EEXIST;
515 }
516 return 0;
517 }
518
519 static struct extent_state *next_state(struct extent_state *state)
520 {
521 struct rb_node *next = rb_next(&state->rb_node);
522 if (next)
523 return rb_entry(next, struct extent_state, rb_node);
524 else
525 return NULL;
526 }
527
528 /*
529 * utility function to clear some bits in an extent state struct.
530 * it will optionally wake up any one waiting on this state (wake == 1).
531 *
532 * If no bits are set on the state struct after clearing things, the
533 * struct is freed and removed from the tree
534 */
535 static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
536 struct extent_state *state,
537 unsigned *bits, int wake,
538 struct extent_changeset *changeset)
539 {
540 struct extent_state *next;
541 unsigned bits_to_clear = *bits & ~EXTENT_CTLBITS;
542
543 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
544 u64 range = state->end - state->start + 1;
545 WARN_ON(range > tree->dirty_bytes);
546 tree->dirty_bytes -= range;
547 }
548 clear_state_cb(tree, state, bits);
549 add_extent_changeset(state, bits_to_clear, changeset, 0);
550 state->state &= ~bits_to_clear;
551 if (wake)
552 wake_up(&state->wq);
553 if (state->state == 0) {
554 next = next_state(state);
555 if (extent_state_in_tree(state)) {
556 rb_erase(&state->rb_node, &tree->state);
557 RB_CLEAR_NODE(&state->rb_node);
558 free_extent_state(state);
559 } else {
560 WARN_ON(1);
561 }
562 } else {
563 merge_state(tree, state);
564 next = next_state(state);
565 }
566 return next;
567 }
568
569 static struct extent_state *
570 alloc_extent_state_atomic(struct extent_state *prealloc)
571 {
572 if (!prealloc)
573 prealloc = alloc_extent_state(GFP_ATOMIC);
574
575 return prealloc;
576 }
577
578 static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
579 {
580 btrfs_panic(tree_fs_info(tree), err,
581 "Locking error: Extent tree was modified by another thread while locked.");
582 }
583
584 /*
585 * clear some bits on a range in the tree. This may require splitting
586 * or inserting elements in the tree, so the gfp mask is used to
587 * indicate which allocations or sleeping are allowed.
588 *
589 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
590 * the given range from the tree regardless of state (ie for truncate).
591 *
592 * the range [start, end] is inclusive.
593 *
594 * This takes the tree lock, and returns 0 on success and < 0 on error.
595 */
596 static int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
597 unsigned bits, int wake, int delete,
598 struct extent_state **cached_state,
599 gfp_t mask, struct extent_changeset *changeset)
600 {
601 struct extent_state *state;
602 struct extent_state *cached;
603 struct extent_state *prealloc = NULL;
604 struct rb_node *node;
605 u64 last_end;
606 int err;
607 int clear = 0;
608
609 btrfs_debug_check_extent_io_range(tree, start, end);
610
611 if (bits & EXTENT_DELALLOC)
612 bits |= EXTENT_NORESERVE;
613
614 if (delete)
615 bits |= ~EXTENT_CTLBITS;
616 bits |= EXTENT_FIRST_DELALLOC;
617
618 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
619 clear = 1;
620 again:
621 if (!prealloc && gfpflags_allow_blocking(mask)) {
622 /*
623 * Don't care for allocation failure here because we might end
624 * up not needing the pre-allocated extent state at all, which
625 * is the case if we only have in the tree extent states that
626 * cover our input range and don't cover too any other range.
627 * If we end up needing a new extent state we allocate it later.
628 */
629 prealloc = alloc_extent_state(mask);
630 }
631
632 spin_lock(&tree->lock);
633 if (cached_state) {
634 cached = *cached_state;
635
636 if (clear) {
637 *cached_state = NULL;
638 cached_state = NULL;
639 }
640
641 if (cached && extent_state_in_tree(cached) &&
642 cached->start <= start && cached->end > start) {
643 if (clear)
644 refcount_dec(&cached->refs);
645 state = cached;
646 goto hit_next;
647 }
648 if (clear)
649 free_extent_state(cached);
650 }
651 /*
652 * this search will find the extents that end after
653 * our range starts
654 */
655 node = tree_search(tree, start);
656 if (!node)
657 goto out;
658 state = rb_entry(node, struct extent_state, rb_node);
659 hit_next:
660 if (state->start > end)
661 goto out;
662 WARN_ON(state->end < start);
663 last_end = state->end;
664
665 /* the state doesn't have the wanted bits, go ahead */
666 if (!(state->state & bits)) {
667 state = next_state(state);
668 goto next;
669 }
670
671 /*
672 * | ---- desired range ---- |
673 * | state | or
674 * | ------------- state -------------- |
675 *
676 * We need to split the extent we found, and may flip
677 * bits on second half.
678 *
679 * If the extent we found extends past our range, we
680 * just split and search again. It'll get split again
681 * the next time though.
682 *
683 * If the extent we found is inside our range, we clear
684 * the desired bit on it.
685 */
686
687 if (state->start < start) {
688 prealloc = alloc_extent_state_atomic(prealloc);
689 BUG_ON(!prealloc);
690 err = split_state(tree, state, prealloc, start);
691 if (err)
692 extent_io_tree_panic(tree, err);
693
694 prealloc = NULL;
695 if (err)
696 goto out;
697 if (state->end <= end) {
698 state = clear_state_bit(tree, state, &bits, wake,
699 changeset);
700 goto next;
701 }
702 goto search_again;
703 }
704 /*
705 * | ---- desired range ---- |
706 * | state |
707 * We need to split the extent, and clear the bit
708 * on the first half
709 */
710 if (state->start <= end && state->end > end) {
711 prealloc = alloc_extent_state_atomic(prealloc);
712 BUG_ON(!prealloc);
713 err = split_state(tree, state, prealloc, end + 1);
714 if (err)
715 extent_io_tree_panic(tree, err);
716
717 if (wake)
718 wake_up(&state->wq);
719
720 clear_state_bit(tree, prealloc, &bits, wake, changeset);
721
722 prealloc = NULL;
723 goto out;
724 }
725
726 state = clear_state_bit(tree, state, &bits, wake, changeset);
727 next:
728 if (last_end == (u64)-1)
729 goto out;
730 start = last_end + 1;
731 if (start <= end && state && !need_resched())
732 goto hit_next;
733
734 search_again:
735 if (start > end)
736 goto out;
737 spin_unlock(&tree->lock);
738 if (gfpflags_allow_blocking(mask))
739 cond_resched();
740 goto again;
741
742 out:
743 spin_unlock(&tree->lock);
744 if (prealloc)
745 free_extent_state(prealloc);
746
747 return 0;
748
749 }
750
751 static void wait_on_state(struct extent_io_tree *tree,
752 struct extent_state *state)
753 __releases(tree->lock)
754 __acquires(tree->lock)
755 {
756 DEFINE_WAIT(wait);
757 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
758 spin_unlock(&tree->lock);
759 schedule();
760 spin_lock(&tree->lock);
761 finish_wait(&state->wq, &wait);
762 }
763
764 /*
765 * waits for one or more bits to clear on a range in the state tree.
766 * The range [start, end] is inclusive.
767 * The tree lock is taken by this function
768 */
769 static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
770 unsigned long bits)
771 {
772 struct extent_state *state;
773 struct rb_node *node;
774
775 btrfs_debug_check_extent_io_range(tree, start, end);
776
777 spin_lock(&tree->lock);
778 again:
779 while (1) {
780 /*
781 * this search will find all the extents that end after
782 * our range starts
783 */
784 node = tree_search(tree, start);
785 process_node:
786 if (!node)
787 break;
788
789 state = rb_entry(node, struct extent_state, rb_node);
790
791 if (state->start > end)
792 goto out;
793
794 if (state->state & bits) {
795 start = state->start;
796 refcount_inc(&state->refs);
797 wait_on_state(tree, state);
798 free_extent_state(state);
799 goto again;
800 }
801 start = state->end + 1;
802
803 if (start > end)
804 break;
805
806 if (!cond_resched_lock(&tree->lock)) {
807 node = rb_next(node);
808 goto process_node;
809 }
810 }
811 out:
812 spin_unlock(&tree->lock);
813 }
814
815 static void set_state_bits(struct extent_io_tree *tree,
816 struct extent_state *state,
817 unsigned *bits, struct extent_changeset *changeset)
818 {
819 unsigned bits_to_set = *bits & ~EXTENT_CTLBITS;
820
821 set_state_cb(tree, state, bits);
822 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
823 u64 range = state->end - state->start + 1;
824 tree->dirty_bytes += range;
825 }
826 add_extent_changeset(state, bits_to_set, changeset, 1);
827 state->state |= bits_to_set;
828 }
829
830 static void cache_state_if_flags(struct extent_state *state,
831 struct extent_state **cached_ptr,
832 unsigned flags)
833 {
834 if (cached_ptr && !(*cached_ptr)) {
835 if (!flags || (state->state & flags)) {
836 *cached_ptr = state;
837 refcount_inc(&state->refs);
838 }
839 }
840 }
841
842 static void cache_state(struct extent_state *state,
843 struct extent_state **cached_ptr)
844 {
845 return cache_state_if_flags(state, cached_ptr,
846 EXTENT_IOBITS | EXTENT_BOUNDARY);
847 }
848
849 /*
850 * set some bits on a range in the tree. This may require allocations or
851 * sleeping, so the gfp mask is used to indicate what is allowed.
852 *
853 * If any of the exclusive bits are set, this will fail with -EEXIST if some
854 * part of the range already has the desired bits set. The start of the
855 * existing range is returned in failed_start in this case.
856 *
857 * [start, end] is inclusive This takes the tree lock.
858 */
859
860 static int __must_check
861 __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
862 unsigned bits, unsigned exclusive_bits,
863 u64 *failed_start, struct extent_state **cached_state,
864 gfp_t mask, struct extent_changeset *changeset)
865 {
866 struct extent_state *state;
867 struct extent_state *prealloc = NULL;
868 struct rb_node *node;
869 struct rb_node **p;
870 struct rb_node *parent;
871 int err = 0;
872 u64 last_start;
873 u64 last_end;
874
875 btrfs_debug_check_extent_io_range(tree, start, end);
876
877 bits |= EXTENT_FIRST_DELALLOC;
878 again:
879 if (!prealloc && gfpflags_allow_blocking(mask)) {
880 /*
881 * Don't care for allocation failure here because we might end
882 * up not needing the pre-allocated extent state at all, which
883 * is the case if we only have in the tree extent states that
884 * cover our input range and don't cover too any other range.
885 * If we end up needing a new extent state we allocate it later.
886 */
887 prealloc = alloc_extent_state(mask);
888 }
889
890 spin_lock(&tree->lock);
891 if (cached_state && *cached_state) {
892 state = *cached_state;
893 if (state->start <= start && state->end > start &&
894 extent_state_in_tree(state)) {
895 node = &state->rb_node;
896 goto hit_next;
897 }
898 }
899 /*
900 * this search will find all the extents that end after
901 * our range starts.
902 */
903 node = tree_search_for_insert(tree, start, &p, &parent);
904 if (!node) {
905 prealloc = alloc_extent_state_atomic(prealloc);
906 BUG_ON(!prealloc);
907 err = insert_state(tree, prealloc, start, end,
908 &p, &parent, &bits, changeset);
909 if (err)
910 extent_io_tree_panic(tree, err);
911
912 cache_state(prealloc, cached_state);
913 prealloc = NULL;
914 goto out;
915 }
916 state = rb_entry(node, struct extent_state, rb_node);
917 hit_next:
918 last_start = state->start;
919 last_end = state->end;
920
921 /*
922 * | ---- desired range ---- |
923 * | state |
924 *
925 * Just lock what we found and keep going
926 */
927 if (state->start == start && state->end <= end) {
928 if (state->state & exclusive_bits) {
929 *failed_start = state->start;
930 err = -EEXIST;
931 goto out;
932 }
933
934 set_state_bits(tree, state, &bits, changeset);
935 cache_state(state, cached_state);
936 merge_state(tree, state);
937 if (last_end == (u64)-1)
938 goto out;
939 start = last_end + 1;
940 state = next_state(state);
941 if (start < end && state && state->start == start &&
942 !need_resched())
943 goto hit_next;
944 goto search_again;
945 }
946
947 /*
948 * | ---- desired range ---- |
949 * | state |
950 * or
951 * | ------------- state -------------- |
952 *
953 * We need to split the extent we found, and may flip bits on
954 * second half.
955 *
956 * If the extent we found extends past our
957 * range, we just split and search again. It'll get split
958 * again the next time though.
959 *
960 * If the extent we found is inside our range, we set the
961 * desired bit on it.
962 */
963 if (state->start < start) {
964 if (state->state & exclusive_bits) {
965 *failed_start = start;
966 err = -EEXIST;
967 goto out;
968 }
969
970 prealloc = alloc_extent_state_atomic(prealloc);
971 BUG_ON(!prealloc);
972 err = split_state(tree, state, prealloc, start);
973 if (err)
974 extent_io_tree_panic(tree, err);
975
976 prealloc = NULL;
977 if (err)
978 goto out;
979 if (state->end <= end) {
980 set_state_bits(tree, state, &bits, changeset);
981 cache_state(state, cached_state);
982 merge_state(tree, state);
983 if (last_end == (u64)-1)
984 goto out;
985 start = last_end + 1;
986 state = next_state(state);
987 if (start < end && state && state->start == start &&
988 !need_resched())
989 goto hit_next;
990 }
991 goto search_again;
992 }
993 /*
994 * | ---- desired range ---- |
995 * | state | or | state |
996 *
997 * There's a hole, we need to insert something in it and
998 * ignore the extent we found.
999 */
1000 if (state->start > start) {
1001 u64 this_end;
1002 if (end < last_start)
1003 this_end = end;
1004 else
1005 this_end = last_start - 1;
1006
1007 prealloc = alloc_extent_state_atomic(prealloc);
1008 BUG_ON(!prealloc);
1009
1010 /*
1011 * Avoid to free 'prealloc' if it can be merged with
1012 * the later extent.
1013 */
1014 err = insert_state(tree, prealloc, start, this_end,
1015 NULL, NULL, &bits, changeset);
1016 if (err)
1017 extent_io_tree_panic(tree, err);
1018
1019 cache_state(prealloc, cached_state);
1020 prealloc = NULL;
1021 start = this_end + 1;
1022 goto search_again;
1023 }
1024 /*
1025 * | ---- desired range ---- |
1026 * | state |
1027 * We need to split the extent, and set the bit
1028 * on the first half
1029 */
1030 if (state->start <= end && state->end > end) {
1031 if (state->state & exclusive_bits) {
1032 *failed_start = start;
1033 err = -EEXIST;
1034 goto out;
1035 }
1036
1037 prealloc = alloc_extent_state_atomic(prealloc);
1038 BUG_ON(!prealloc);
1039 err = split_state(tree, state, prealloc, end + 1);
1040 if (err)
1041 extent_io_tree_panic(tree, err);
1042
1043 set_state_bits(tree, prealloc, &bits, changeset);
1044 cache_state(prealloc, cached_state);
1045 merge_state(tree, prealloc);
1046 prealloc = NULL;
1047 goto out;
1048 }
1049
1050 search_again:
1051 if (start > end)
1052 goto out;
1053 spin_unlock(&tree->lock);
1054 if (gfpflags_allow_blocking(mask))
1055 cond_resched();
1056 goto again;
1057
1058 out:
1059 spin_unlock(&tree->lock);
1060 if (prealloc)
1061 free_extent_state(prealloc);
1062
1063 return err;
1064
1065 }
1066
1067 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1068 unsigned bits, u64 * failed_start,
1069 struct extent_state **cached_state, gfp_t mask)
1070 {
1071 return __set_extent_bit(tree, start, end, bits, 0, failed_start,
1072 cached_state, mask, NULL);
1073 }
1074
1075
1076 /**
1077 * convert_extent_bit - convert all bits in a given range from one bit to
1078 * another
1079 * @tree: the io tree to search
1080 * @start: the start offset in bytes
1081 * @end: the end offset in bytes (inclusive)
1082 * @bits: the bits to set in this range
1083 * @clear_bits: the bits to clear in this range
1084 * @cached_state: state that we're going to cache
1085 *
1086 * This will go through and set bits for the given range. If any states exist
1087 * already in this range they are set with the given bit and cleared of the
1088 * clear_bits. This is only meant to be used by things that are mergeable, ie
1089 * converting from say DELALLOC to DIRTY. This is not meant to be used with
1090 * boundary bits like LOCK.
1091 *
1092 * All allocations are done with GFP_NOFS.
1093 */
1094 int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1095 unsigned bits, unsigned clear_bits,
1096 struct extent_state **cached_state)
1097 {
1098 struct extent_state *state;
1099 struct extent_state *prealloc = NULL;
1100 struct rb_node *node;
1101 struct rb_node **p;
1102 struct rb_node *parent;
1103 int err = 0;
1104 u64 last_start;
1105 u64 last_end;
1106 bool first_iteration = true;
1107
1108 btrfs_debug_check_extent_io_range(tree, start, end);
1109
1110 again:
1111 if (!prealloc) {
1112 /*
1113 * Best effort, don't worry if extent state allocation fails
1114 * here for the first iteration. We might have a cached state
1115 * that matches exactly the target range, in which case no
1116 * extent state allocations are needed. We'll only know this
1117 * after locking the tree.
1118 */
1119 prealloc = alloc_extent_state(GFP_NOFS);
1120 if (!prealloc && !first_iteration)
1121 return -ENOMEM;
1122 }
1123
1124 spin_lock(&tree->lock);
1125 if (cached_state && *cached_state) {
1126 state = *cached_state;
1127 if (state->start <= start && state->end > start &&
1128 extent_state_in_tree(state)) {
1129 node = &state->rb_node;
1130 goto hit_next;
1131 }
1132 }
1133
1134 /*
1135 * this search will find all the extents that end after
1136 * our range starts.
1137 */
1138 node = tree_search_for_insert(tree, start, &p, &parent);
1139 if (!node) {
1140 prealloc = alloc_extent_state_atomic(prealloc);
1141 if (!prealloc) {
1142 err = -ENOMEM;
1143 goto out;
1144 }
1145 err = insert_state(tree, prealloc, start, end,
1146 &p, &parent, &bits, NULL);
1147 if (err)
1148 extent_io_tree_panic(tree, err);
1149 cache_state(prealloc, cached_state);
1150 prealloc = NULL;
1151 goto out;
1152 }
1153 state = rb_entry(node, struct extent_state, rb_node);
1154 hit_next:
1155 last_start = state->start;
1156 last_end = state->end;
1157
1158 /*
1159 * | ---- desired range ---- |
1160 * | state |
1161 *
1162 * Just lock what we found and keep going
1163 */
1164 if (state->start == start && state->end <= end) {
1165 set_state_bits(tree, state, &bits, NULL);
1166 cache_state(state, cached_state);
1167 state = clear_state_bit(tree, state, &clear_bits, 0, NULL);
1168 if (last_end == (u64)-1)
1169 goto out;
1170 start = last_end + 1;
1171 if (start < end && state && state->start == start &&
1172 !need_resched())
1173 goto hit_next;
1174 goto search_again;
1175 }
1176
1177 /*
1178 * | ---- desired range ---- |
1179 * | state |
1180 * or
1181 * | ------------- state -------------- |
1182 *
1183 * We need to split the extent we found, and may flip bits on
1184 * second half.
1185 *
1186 * If the extent we found extends past our
1187 * range, we just split and search again. It'll get split
1188 * again the next time though.
1189 *
1190 * If the extent we found is inside our range, we set the
1191 * desired bit on it.
1192 */
1193 if (state->start < start) {
1194 prealloc = alloc_extent_state_atomic(prealloc);
1195 if (!prealloc) {
1196 err = -ENOMEM;
1197 goto out;
1198 }
1199 err = split_state(tree, state, prealloc, start);
1200 if (err)
1201 extent_io_tree_panic(tree, err);
1202 prealloc = NULL;
1203 if (err)
1204 goto out;
1205 if (state->end <= end) {
1206 set_state_bits(tree, state, &bits, NULL);
1207 cache_state(state, cached_state);
1208 state = clear_state_bit(tree, state, &clear_bits, 0,
1209 NULL);
1210 if (last_end == (u64)-1)
1211 goto out;
1212 start = last_end + 1;
1213 if (start < end && state && state->start == start &&
1214 !need_resched())
1215 goto hit_next;
1216 }
1217 goto search_again;
1218 }
1219 /*
1220 * | ---- desired range ---- |
1221 * | state | or | state |
1222 *
1223 * There's a hole, we need to insert something in it and
1224 * ignore the extent we found.
1225 */
1226 if (state->start > start) {
1227 u64 this_end;
1228 if (end < last_start)
1229 this_end = end;
1230 else
1231 this_end = last_start - 1;
1232
1233 prealloc = alloc_extent_state_atomic(prealloc);
1234 if (!prealloc) {
1235 err = -ENOMEM;
1236 goto out;
1237 }
1238
1239 /*
1240 * Avoid to free 'prealloc' if it can be merged with
1241 * the later extent.
1242 */
1243 err = insert_state(tree, prealloc, start, this_end,
1244 NULL, NULL, &bits, NULL);
1245 if (err)
1246 extent_io_tree_panic(tree, err);
1247 cache_state(prealloc, cached_state);
1248 prealloc = NULL;
1249 start = this_end + 1;
1250 goto search_again;
1251 }
1252 /*
1253 * | ---- desired range ---- |
1254 * | state |
1255 * We need to split the extent, and set the bit
1256 * on the first half
1257 */
1258 if (state->start <= end && state->end > end) {
1259 prealloc = alloc_extent_state_atomic(prealloc);
1260 if (!prealloc) {
1261 err = -ENOMEM;
1262 goto out;
1263 }
1264
1265 err = split_state(tree, state, prealloc, end + 1);
1266 if (err)
1267 extent_io_tree_panic(tree, err);
1268
1269 set_state_bits(tree, prealloc, &bits, NULL);
1270 cache_state(prealloc, cached_state);
1271 clear_state_bit(tree, prealloc, &clear_bits, 0, NULL);
1272 prealloc = NULL;
1273 goto out;
1274 }
1275
1276 search_again:
1277 if (start > end)
1278 goto out;
1279 spin_unlock(&tree->lock);
1280 cond_resched();
1281 first_iteration = false;
1282 goto again;
1283
1284 out:
1285 spin_unlock(&tree->lock);
1286 if (prealloc)
1287 free_extent_state(prealloc);
1288
1289 return err;
1290 }
1291
1292 /* wrappers around set/clear extent bit */
1293 int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1294 unsigned bits, struct extent_changeset *changeset)
1295 {
1296 /*
1297 * We don't support EXTENT_LOCKED yet, as current changeset will
1298 * record any bits changed, so for EXTENT_LOCKED case, it will
1299 * either fail with -EEXIST or changeset will record the whole
1300 * range.
1301 */
1302 BUG_ON(bits & EXTENT_LOCKED);
1303
1304 return __set_extent_bit(tree, start, end, bits, 0, NULL, NULL, GFP_NOFS,
1305 changeset);
1306 }
1307
1308 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1309 unsigned bits, int wake, int delete,
1310 struct extent_state **cached, gfp_t mask)
1311 {
1312 return __clear_extent_bit(tree, start, end, bits, wake, delete,
1313 cached, mask, NULL);
1314 }
1315
1316 int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1317 unsigned bits, struct extent_changeset *changeset)
1318 {
1319 /*
1320 * Don't support EXTENT_LOCKED case, same reason as
1321 * set_record_extent_bits().
1322 */
1323 BUG_ON(bits & EXTENT_LOCKED);
1324
1325 return __clear_extent_bit(tree, start, end, bits, 0, 0, NULL, GFP_NOFS,
1326 changeset);
1327 }
1328
1329 /*
1330 * either insert or lock state struct between start and end use mask to tell
1331 * us if waiting is desired.
1332 */
1333 int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1334 struct extent_state **cached_state)
1335 {
1336 int err;
1337 u64 failed_start;
1338
1339 while (1) {
1340 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED,
1341 EXTENT_LOCKED, &failed_start,
1342 cached_state, GFP_NOFS, NULL);
1343 if (err == -EEXIST) {
1344 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
1345 start = failed_start;
1346 } else
1347 break;
1348 WARN_ON(start > end);
1349 }
1350 return err;
1351 }
1352
1353 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1354 {
1355 int err;
1356 u64 failed_start;
1357
1358 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1359 &failed_start, NULL, GFP_NOFS, NULL);
1360 if (err == -EEXIST) {
1361 if (failed_start > start)
1362 clear_extent_bit(tree, start, failed_start - 1,
1363 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
1364 return 0;
1365 }
1366 return 1;
1367 }
1368
1369 void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
1370 {
1371 unsigned long index = start >> PAGE_SHIFT;
1372 unsigned long end_index = end >> PAGE_SHIFT;
1373 struct page *page;
1374
1375 while (index <= end_index) {
1376 page = find_get_page(inode->i_mapping, index);
1377 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1378 clear_page_dirty_for_io(page);
1379 put_page(page);
1380 index++;
1381 }
1382 }
1383
1384 void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
1385 {
1386 unsigned long index = start >> PAGE_SHIFT;
1387 unsigned long end_index = end >> PAGE_SHIFT;
1388 struct page *page;
1389
1390 while (index <= end_index) {
1391 page = find_get_page(inode->i_mapping, index);
1392 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1393 __set_page_dirty_nobuffers(page);
1394 account_page_redirty(page);
1395 put_page(page);
1396 index++;
1397 }
1398 }
1399
1400 /*
1401 * helper function to set both pages and extents in the tree writeback
1402 */
1403 static void set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1404 {
1405 unsigned long index = start >> PAGE_SHIFT;
1406 unsigned long end_index = end >> PAGE_SHIFT;
1407 struct page *page;
1408
1409 while (index <= end_index) {
1410 page = find_get_page(tree->mapping, index);
1411 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1412 set_page_writeback(page);
1413 put_page(page);
1414 index++;
1415 }
1416 }
1417
1418 /* find the first state struct with 'bits' set after 'start', and
1419 * return it. tree->lock must be held. NULL will returned if
1420 * nothing was found after 'start'
1421 */
1422 static struct extent_state *
1423 find_first_extent_bit_state(struct extent_io_tree *tree,
1424 u64 start, unsigned bits)
1425 {
1426 struct rb_node *node;
1427 struct extent_state *state;
1428
1429 /*
1430 * this search will find all the extents that end after
1431 * our range starts.
1432 */
1433 node = tree_search(tree, start);
1434 if (!node)
1435 goto out;
1436
1437 while (1) {
1438 state = rb_entry(node, struct extent_state, rb_node);
1439 if (state->end >= start && (state->state & bits))
1440 return state;
1441
1442 node = rb_next(node);
1443 if (!node)
1444 break;
1445 }
1446 out:
1447 return NULL;
1448 }
1449
1450 /*
1451 * find the first offset in the io tree with 'bits' set. zero is
1452 * returned if we find something, and *start_ret and *end_ret are
1453 * set to reflect the state struct that was found.
1454 *
1455 * If nothing was found, 1 is returned. If found something, return 0.
1456 */
1457 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1458 u64 *start_ret, u64 *end_ret, unsigned bits,
1459 struct extent_state **cached_state)
1460 {
1461 struct extent_state *state;
1462 struct rb_node *n;
1463 int ret = 1;
1464
1465 spin_lock(&tree->lock);
1466 if (cached_state && *cached_state) {
1467 state = *cached_state;
1468 if (state->end == start - 1 && extent_state_in_tree(state)) {
1469 n = rb_next(&state->rb_node);
1470 while (n) {
1471 state = rb_entry(n, struct extent_state,
1472 rb_node);
1473 if (state->state & bits)
1474 goto got_it;
1475 n = rb_next(n);
1476 }
1477 free_extent_state(*cached_state);
1478 *cached_state = NULL;
1479 goto out;
1480 }
1481 free_extent_state(*cached_state);
1482 *cached_state = NULL;
1483 }
1484
1485 state = find_first_extent_bit_state(tree, start, bits);
1486 got_it:
1487 if (state) {
1488 cache_state_if_flags(state, cached_state, 0);
1489 *start_ret = state->start;
1490 *end_ret = state->end;
1491 ret = 0;
1492 }
1493 out:
1494 spin_unlock(&tree->lock);
1495 return ret;
1496 }
1497
1498 /*
1499 * find a contiguous range of bytes in the file marked as delalloc, not
1500 * more than 'max_bytes'. start and end are used to return the range,
1501 *
1502 * 1 is returned if we find something, 0 if nothing was in the tree
1503 */
1504 static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1505 u64 *start, u64 *end, u64 max_bytes,
1506 struct extent_state **cached_state)
1507 {
1508 struct rb_node *node;
1509 struct extent_state *state;
1510 u64 cur_start = *start;
1511 u64 found = 0;
1512 u64 total_bytes = 0;
1513
1514 spin_lock(&tree->lock);
1515
1516 /*
1517 * this search will find all the extents that end after
1518 * our range starts.
1519 */
1520 node = tree_search(tree, cur_start);
1521 if (!node) {
1522 if (!found)
1523 *end = (u64)-1;
1524 goto out;
1525 }
1526
1527 while (1) {
1528 state = rb_entry(node, struct extent_state, rb_node);
1529 if (found && (state->start != cur_start ||
1530 (state->state & EXTENT_BOUNDARY))) {
1531 goto out;
1532 }
1533 if (!(state->state & EXTENT_DELALLOC)) {
1534 if (!found)
1535 *end = state->end;
1536 goto out;
1537 }
1538 if (!found) {
1539 *start = state->start;
1540 *cached_state = state;
1541 refcount_inc(&state->refs);
1542 }
1543 found++;
1544 *end = state->end;
1545 cur_start = state->end + 1;
1546 node = rb_next(node);
1547 total_bytes += state->end - state->start + 1;
1548 if (total_bytes >= max_bytes)
1549 break;
1550 if (!node)
1551 break;
1552 }
1553 out:
1554 spin_unlock(&tree->lock);
1555 return found;
1556 }
1557
1558 static int __process_pages_contig(struct address_space *mapping,
1559 struct page *locked_page,
1560 pgoff_t start_index, pgoff_t end_index,
1561 unsigned long page_ops, pgoff_t *index_ret);
1562
1563 static noinline void __unlock_for_delalloc(struct inode *inode,
1564 struct page *locked_page,
1565 u64 start, u64 end)
1566 {
1567 unsigned long index = start >> PAGE_SHIFT;
1568 unsigned long end_index = end >> PAGE_SHIFT;
1569
1570 ASSERT(locked_page);
1571 if (index == locked_page->index && end_index == index)
1572 return;
1573
1574 __process_pages_contig(inode->i_mapping, locked_page, index, end_index,
1575 PAGE_UNLOCK, NULL);
1576 }
1577
1578 static noinline int lock_delalloc_pages(struct inode *inode,
1579 struct page *locked_page,
1580 u64 delalloc_start,
1581 u64 delalloc_end)
1582 {
1583 unsigned long index = delalloc_start >> PAGE_SHIFT;
1584 unsigned long index_ret = index;
1585 unsigned long end_index = delalloc_end >> PAGE_SHIFT;
1586 int ret;
1587
1588 ASSERT(locked_page);
1589 if (index == locked_page->index && index == end_index)
1590 return 0;
1591
1592 ret = __process_pages_contig(inode->i_mapping, locked_page, index,
1593 end_index, PAGE_LOCK, &index_ret);
1594 if (ret == -EAGAIN)
1595 __unlock_for_delalloc(inode, locked_page, delalloc_start,
1596 (u64)index_ret << PAGE_SHIFT);
1597 return ret;
1598 }
1599
1600 /*
1601 * find a contiguous range of bytes in the file marked as delalloc, not
1602 * more than 'max_bytes'. start and end are used to return the range,
1603 *
1604 * 1 is returned if we find something, 0 if nothing was in the tree
1605 */
1606 STATIC u64 find_lock_delalloc_range(struct inode *inode,
1607 struct extent_io_tree *tree,
1608 struct page *locked_page, u64 *start,
1609 u64 *end, u64 max_bytes)
1610 {
1611 u64 delalloc_start;
1612 u64 delalloc_end;
1613 u64 found;
1614 struct extent_state *cached_state = NULL;
1615 int ret;
1616 int loops = 0;
1617
1618 again:
1619 /* step one, find a bunch of delalloc bytes starting at start */
1620 delalloc_start = *start;
1621 delalloc_end = 0;
1622 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1623 max_bytes, &cached_state);
1624 if (!found || delalloc_end <= *start) {
1625 *start = delalloc_start;
1626 *end = delalloc_end;
1627 free_extent_state(cached_state);
1628 return 0;
1629 }
1630
1631 /*
1632 * start comes from the offset of locked_page. We have to lock
1633 * pages in order, so we can't process delalloc bytes before
1634 * locked_page
1635 */
1636 if (delalloc_start < *start)
1637 delalloc_start = *start;
1638
1639 /*
1640 * make sure to limit the number of pages we try to lock down
1641 */
1642 if (delalloc_end + 1 - delalloc_start > max_bytes)
1643 delalloc_end = delalloc_start + max_bytes - 1;
1644
1645 /* step two, lock all the pages after the page that has start */
1646 ret = lock_delalloc_pages(inode, locked_page,
1647 delalloc_start, delalloc_end);
1648 if (ret == -EAGAIN) {
1649 /* some of the pages are gone, lets avoid looping by
1650 * shortening the size of the delalloc range we're searching
1651 */
1652 free_extent_state(cached_state);
1653 cached_state = NULL;
1654 if (!loops) {
1655 max_bytes = PAGE_SIZE;
1656 loops = 1;
1657 goto again;
1658 } else {
1659 found = 0;
1660 goto out_failed;
1661 }
1662 }
1663 BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
1664
1665 /* step three, lock the state bits for the whole range */
1666 lock_extent_bits(tree, delalloc_start, delalloc_end, &cached_state);
1667
1668 /* then test to make sure it is all still delalloc */
1669 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1670 EXTENT_DELALLOC, 1, cached_state);
1671 if (!ret) {
1672 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1673 &cached_state, GFP_NOFS);
1674 __unlock_for_delalloc(inode, locked_page,
1675 delalloc_start, delalloc_end);
1676 cond_resched();
1677 goto again;
1678 }
1679 free_extent_state(cached_state);
1680 *start = delalloc_start;
1681 *end = delalloc_end;
1682 out_failed:
1683 return found;
1684 }
1685
1686 static int __process_pages_contig(struct address_space *mapping,
1687 struct page *locked_page,
1688 pgoff_t start_index, pgoff_t end_index,
1689 unsigned long page_ops, pgoff_t *index_ret)
1690 {
1691 unsigned long nr_pages = end_index - start_index + 1;
1692 unsigned long pages_locked = 0;
1693 pgoff_t index = start_index;
1694 struct page *pages[16];
1695 unsigned ret;
1696 int err = 0;
1697 int i;
1698
1699 if (page_ops & PAGE_LOCK) {
1700 ASSERT(page_ops == PAGE_LOCK);
1701 ASSERT(index_ret && *index_ret == start_index);
1702 }
1703
1704 if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
1705 mapping_set_error(mapping, -EIO);
1706
1707 while (nr_pages > 0) {
1708 ret = find_get_pages_contig(mapping, index,
1709 min_t(unsigned long,
1710 nr_pages, ARRAY_SIZE(pages)), pages);
1711 if (ret == 0) {
1712 /*
1713 * Only if we're going to lock these pages,
1714 * can we find nothing at @index.
1715 */
1716 ASSERT(page_ops & PAGE_LOCK);
1717 err = -EAGAIN;
1718 goto out;
1719 }
1720
1721 for (i = 0; i < ret; i++) {
1722 if (page_ops & PAGE_SET_PRIVATE2)
1723 SetPagePrivate2(pages[i]);
1724
1725 if (pages[i] == locked_page) {
1726 put_page(pages[i]);
1727 pages_locked++;
1728 continue;
1729 }
1730 if (page_ops & PAGE_CLEAR_DIRTY)
1731 clear_page_dirty_for_io(pages[i]);
1732 if (page_ops & PAGE_SET_WRITEBACK)
1733 set_page_writeback(pages[i]);
1734 if (page_ops & PAGE_SET_ERROR)
1735 SetPageError(pages[i]);
1736 if (page_ops & PAGE_END_WRITEBACK)
1737 end_page_writeback(pages[i]);
1738 if (page_ops & PAGE_UNLOCK)
1739 unlock_page(pages[i]);
1740 if (page_ops & PAGE_LOCK) {
1741 lock_page(pages[i]);
1742 if (!PageDirty(pages[i]) ||
1743 pages[i]->mapping != mapping) {
1744 unlock_page(pages[i]);
1745 put_page(pages[i]);
1746 err = -EAGAIN;
1747 goto out;
1748 }
1749 }
1750 put_page(pages[i]);
1751 pages_locked++;
1752 }
1753 nr_pages -= ret;
1754 index += ret;
1755 cond_resched();
1756 }
1757 out:
1758 if (err && index_ret)
1759 *index_ret = start_index + pages_locked - 1;
1760 return err;
1761 }
1762
1763 void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
1764 u64 delalloc_end, struct page *locked_page,
1765 unsigned clear_bits,
1766 unsigned long page_ops)
1767 {
1768 clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, clear_bits, 1, 0,
1769 NULL, GFP_NOFS);
1770
1771 __process_pages_contig(inode->i_mapping, locked_page,
1772 start >> PAGE_SHIFT, end >> PAGE_SHIFT,
1773 page_ops, NULL);
1774 }
1775
1776 /*
1777 * count the number of bytes in the tree that have a given bit(s)
1778 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1779 * cached. The total number found is returned.
1780 */
1781 u64 count_range_bits(struct extent_io_tree *tree,
1782 u64 *start, u64 search_end, u64 max_bytes,
1783 unsigned bits, int contig)
1784 {
1785 struct rb_node *node;
1786 struct extent_state *state;
1787 u64 cur_start = *start;
1788 u64 total_bytes = 0;
1789 u64 last = 0;
1790 int found = 0;
1791
1792 if (WARN_ON(search_end <= cur_start))
1793 return 0;
1794
1795 spin_lock(&tree->lock);
1796 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1797 total_bytes = tree->dirty_bytes;
1798 goto out;
1799 }
1800 /*
1801 * this search will find all the extents that end after
1802 * our range starts.
1803 */
1804 node = tree_search(tree, cur_start);
1805 if (!node)
1806 goto out;
1807
1808 while (1) {
1809 state = rb_entry(node, struct extent_state, rb_node);
1810 if (state->start > search_end)
1811 break;
1812 if (contig && found && state->start > last + 1)
1813 break;
1814 if (state->end >= cur_start && (state->state & bits) == bits) {
1815 total_bytes += min(search_end, state->end) + 1 -
1816 max(cur_start, state->start);
1817 if (total_bytes >= max_bytes)
1818 break;
1819 if (!found) {
1820 *start = max(cur_start, state->start);
1821 found = 1;
1822 }
1823 last = state->end;
1824 } else if (contig && found) {
1825 break;
1826 }
1827 node = rb_next(node);
1828 if (!node)
1829 break;
1830 }
1831 out:
1832 spin_unlock(&tree->lock);
1833 return total_bytes;
1834 }
1835
1836 /*
1837 * set the private field for a given byte offset in the tree. If there isn't
1838 * an extent_state there already, this does nothing.
1839 */
1840 static noinline int set_state_failrec(struct extent_io_tree *tree, u64 start,
1841 struct io_failure_record *failrec)
1842 {
1843 struct rb_node *node;
1844 struct extent_state *state;
1845 int ret = 0;
1846
1847 spin_lock(&tree->lock);
1848 /*
1849 * this search will find all the extents that end after
1850 * our range starts.
1851 */
1852 node = tree_search(tree, start);
1853 if (!node) {
1854 ret = -ENOENT;
1855 goto out;
1856 }
1857 state = rb_entry(node, struct extent_state, rb_node);
1858 if (state->start != start) {
1859 ret = -ENOENT;
1860 goto out;
1861 }
1862 state->failrec = failrec;
1863 out:
1864 spin_unlock(&tree->lock);
1865 return ret;
1866 }
1867
1868 static noinline int get_state_failrec(struct extent_io_tree *tree, u64 start,
1869 struct io_failure_record **failrec)
1870 {
1871 struct rb_node *node;
1872 struct extent_state *state;
1873 int ret = 0;
1874
1875 spin_lock(&tree->lock);
1876 /*
1877 * this search will find all the extents that end after
1878 * our range starts.
1879 */
1880 node = tree_search(tree, start);
1881 if (!node) {
1882 ret = -ENOENT;
1883 goto out;
1884 }
1885 state = rb_entry(node, struct extent_state, rb_node);
1886 if (state->start != start) {
1887 ret = -ENOENT;
1888 goto out;
1889 }
1890 *failrec = state->failrec;
1891 out:
1892 spin_unlock(&tree->lock);
1893 return ret;
1894 }
1895
1896 /*
1897 * searches a range in the state tree for a given mask.
1898 * If 'filled' == 1, this returns 1 only if every extent in the tree
1899 * has the bits set. Otherwise, 1 is returned if any bit in the
1900 * range is found set.
1901 */
1902 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1903 unsigned bits, int filled, struct extent_state *cached)
1904 {
1905 struct extent_state *state = NULL;
1906 struct rb_node *node;
1907 int bitset = 0;
1908
1909 spin_lock(&tree->lock);
1910 if (cached && extent_state_in_tree(cached) && cached->start <= start &&
1911 cached->end > start)
1912 node = &cached->rb_node;
1913 else
1914 node = tree_search(tree, start);
1915 while (node && start <= end) {
1916 state = rb_entry(node, struct extent_state, rb_node);
1917
1918 if (filled && state->start > start) {
1919 bitset = 0;
1920 break;
1921 }
1922
1923 if (state->start > end)
1924 break;
1925
1926 if (state->state & bits) {
1927 bitset = 1;
1928 if (!filled)
1929 break;
1930 } else if (filled) {
1931 bitset = 0;
1932 break;
1933 }
1934
1935 if (state->end == (u64)-1)
1936 break;
1937
1938 start = state->end + 1;
1939 if (start > end)
1940 break;
1941 node = rb_next(node);
1942 if (!node) {
1943 if (filled)
1944 bitset = 0;
1945 break;
1946 }
1947 }
1948 spin_unlock(&tree->lock);
1949 return bitset;
1950 }
1951
1952 /*
1953 * helper function to set a given page up to date if all the
1954 * extents in the tree for that page are up to date
1955 */
1956 static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1957 {
1958 u64 start = page_offset(page);
1959 u64 end = start + PAGE_SIZE - 1;
1960 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1961 SetPageUptodate(page);
1962 }
1963
1964 int free_io_failure(struct btrfs_inode *inode, struct io_failure_record *rec)
1965 {
1966 int ret;
1967 int err = 0;
1968 struct extent_io_tree *failure_tree = &inode->io_failure_tree;
1969
1970 set_state_failrec(failure_tree, rec->start, NULL);
1971 ret = clear_extent_bits(failure_tree, rec->start,
1972 rec->start + rec->len - 1,
1973 EXTENT_LOCKED | EXTENT_DIRTY);
1974 if (ret)
1975 err = ret;
1976
1977 ret = clear_extent_bits(&inode->io_tree, rec->start,
1978 rec->start + rec->len - 1,
1979 EXTENT_DAMAGED);
1980 if (ret && !err)
1981 err = ret;
1982
1983 kfree(rec);
1984 return err;
1985 }
1986
1987 /*
1988 * this bypasses the standard btrfs submit functions deliberately, as
1989 * the standard behavior is to write all copies in a raid setup. here we only
1990 * want to write the one bad copy. so we do the mapping for ourselves and issue
1991 * submit_bio directly.
1992 * to avoid any synchronization issues, wait for the data after writing, which
1993 * actually prevents the read that triggered the error from finishing.
1994 * currently, there can be no more than two copies of every data bit. thus,
1995 * exactly one rewrite is required.
1996 */
1997 int repair_io_failure(struct btrfs_inode *inode, u64 start, u64 length,
1998 u64 logical, struct page *page,
1999 unsigned int pg_offset, int mirror_num)
2000 {
2001 struct btrfs_fs_info *fs_info = inode->root->fs_info;
2002 struct bio *bio;
2003 struct btrfs_device *dev;
2004 u64 map_length = 0;
2005 u64 sector;
2006 struct btrfs_bio *bbio = NULL;
2007 int ret;
2008
2009 ASSERT(!(fs_info->sb->s_flags & MS_RDONLY));
2010 BUG_ON(!mirror_num);
2011
2012 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2013 if (!bio)
2014 return -EIO;
2015 bio->bi_iter.bi_size = 0;
2016 map_length = length;
2017
2018 /*
2019 * Avoid races with device replace and make sure our bbio has devices
2020 * associated to its stripes that don't go away while we are doing the
2021 * read repair operation.
2022 */
2023 btrfs_bio_counter_inc_blocked(fs_info);
2024 if (btrfs_is_parity_mirror(fs_info, logical, length, mirror_num)) {
2025 /*
2026 * Note that we don't use BTRFS_MAP_WRITE because it's supposed
2027 * to update all raid stripes, but here we just want to correct
2028 * bad stripe, thus BTRFS_MAP_READ is abused to only get the bad
2029 * stripe's dev and sector.
2030 */
2031 ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
2032 &map_length, &bbio, 0);
2033 if (ret) {
2034 btrfs_bio_counter_dec(fs_info);
2035 bio_put(bio);
2036 return -EIO;
2037 }
2038 ASSERT(bbio->mirror_num == 1);
2039 } else {
2040 ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
2041 &map_length, &bbio, mirror_num);
2042 if (ret) {
2043 btrfs_bio_counter_dec(fs_info);
2044 bio_put(bio);
2045 return -EIO;
2046 }
2047 BUG_ON(mirror_num != bbio->mirror_num);
2048 }
2049
2050 sector = bbio->stripes[bbio->mirror_num - 1].physical >> 9;
2051 bio->bi_iter.bi_sector = sector;
2052 dev = bbio->stripes[bbio->mirror_num - 1].dev;
2053 btrfs_put_bbio(bbio);
2054 if (!dev || !dev->bdev || !dev->writeable) {
2055 btrfs_bio_counter_dec(fs_info);
2056 bio_put(bio);
2057 return -EIO;
2058 }
2059 bio->bi_bdev = dev->bdev;
2060 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
2061 bio_add_page(bio, page, length, pg_offset);
2062
2063 if (btrfsic_submit_bio_wait(bio)) {
2064 /* try to remap that extent elsewhere? */
2065 btrfs_bio_counter_dec(fs_info);
2066 bio_put(bio);
2067 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2068 return -EIO;
2069 }
2070
2071 btrfs_info_rl_in_rcu(fs_info,
2072 "read error corrected: ino %llu off %llu (dev %s sector %llu)",
2073 btrfs_ino(inode), start,
2074 rcu_str_deref(dev->name), sector);
2075 btrfs_bio_counter_dec(fs_info);
2076 bio_put(bio);
2077 return 0;
2078 }
2079
2080 int repair_eb_io_failure(struct btrfs_fs_info *fs_info,
2081 struct extent_buffer *eb, int mirror_num)
2082 {
2083 u64 start = eb->start;
2084 unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
2085 int ret = 0;
2086
2087 if (fs_info->sb->s_flags & MS_RDONLY)
2088 return -EROFS;
2089
2090 for (i = 0; i < num_pages; i++) {
2091 struct page *p = eb->pages[i];
2092
2093 ret = repair_io_failure(BTRFS_I(fs_info->btree_inode), start,
2094 PAGE_SIZE, start, p,
2095 start - page_offset(p), mirror_num);
2096 if (ret)
2097 break;
2098 start += PAGE_SIZE;
2099 }
2100
2101 return ret;
2102 }
2103
2104 /*
2105 * each time an IO finishes, we do a fast check in the IO failure tree
2106 * to see if we need to process or clean up an io_failure_record
2107 */
2108 int clean_io_failure(struct btrfs_inode *inode, u64 start, struct page *page,
2109 unsigned int pg_offset)
2110 {
2111 u64 private;
2112 struct io_failure_record *failrec;
2113 struct btrfs_fs_info *fs_info = inode->root->fs_info;
2114 struct extent_state *state;
2115 int num_copies;
2116 int ret;
2117
2118 private = 0;
2119 ret = count_range_bits(&inode->io_failure_tree, &private,
2120 (u64)-1, 1, EXTENT_DIRTY, 0);
2121 if (!ret)
2122 return 0;
2123
2124 ret = get_state_failrec(&inode->io_failure_tree, start,
2125 &failrec);
2126 if (ret)
2127 return 0;
2128
2129 BUG_ON(!failrec->this_mirror);
2130
2131 if (failrec->in_validation) {
2132 /* there was no real error, just free the record */
2133 btrfs_debug(fs_info,
2134 "clean_io_failure: freeing dummy error at %llu",
2135 failrec->start);
2136 goto out;
2137 }
2138 if (fs_info->sb->s_flags & MS_RDONLY)
2139 goto out;
2140
2141 spin_lock(&inode->io_tree.lock);
2142 state = find_first_extent_bit_state(&inode->io_tree,
2143 failrec->start,
2144 EXTENT_LOCKED);
2145 spin_unlock(&inode->io_tree.lock);
2146
2147 if (state && state->start <= failrec->start &&
2148 state->end >= failrec->start + failrec->len - 1) {
2149 num_copies = btrfs_num_copies(fs_info, failrec->logical,
2150 failrec->len);
2151 if (num_copies > 1) {
2152 repair_io_failure(inode, start, failrec->len,
2153 failrec->logical, page,
2154 pg_offset, failrec->failed_mirror);
2155 }
2156 }
2157
2158 out:
2159 free_io_failure(inode, failrec);
2160
2161 return 0;
2162 }
2163
2164 /*
2165 * Can be called when
2166 * - hold extent lock
2167 * - under ordered extent
2168 * - the inode is freeing
2169 */
2170 void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start, u64 end)
2171 {
2172 struct extent_io_tree *failure_tree = &inode->io_failure_tree;
2173 struct io_failure_record *failrec;
2174 struct extent_state *state, *next;
2175
2176 if (RB_EMPTY_ROOT(&failure_tree->state))
2177 return;
2178
2179 spin_lock(&failure_tree->lock);
2180 state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
2181 while (state) {
2182 if (state->start > end)
2183 break;
2184
2185 ASSERT(state->end <= end);
2186
2187 next = next_state(state);
2188
2189 failrec = state->failrec;
2190 free_extent_state(state);
2191 kfree(failrec);
2192
2193 state = next;
2194 }
2195 spin_unlock(&failure_tree->lock);
2196 }
2197
2198 int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
2199 struct io_failure_record **failrec_ret)
2200 {
2201 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2202 struct io_failure_record *failrec;
2203 struct extent_map *em;
2204 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2205 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2206 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2207 int ret;
2208 u64 logical;
2209
2210 ret = get_state_failrec(failure_tree, start, &failrec);
2211 if (ret) {
2212 failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
2213 if (!failrec)
2214 return -ENOMEM;
2215
2216 failrec->start = start;
2217 failrec->len = end - start + 1;
2218 failrec->this_mirror = 0;
2219 failrec->bio_flags = 0;
2220 failrec->in_validation = 0;
2221
2222 read_lock(&em_tree->lock);
2223 em = lookup_extent_mapping(em_tree, start, failrec->len);
2224 if (!em) {
2225 read_unlock(&em_tree->lock);
2226 kfree(failrec);
2227 return -EIO;
2228 }
2229
2230 if (em->start > start || em->start + em->len <= start) {
2231 free_extent_map(em);
2232 em = NULL;
2233 }
2234 read_unlock(&em_tree->lock);
2235 if (!em) {
2236 kfree(failrec);
2237 return -EIO;
2238 }
2239
2240 logical = start - em->start;
2241 logical = em->block_start + logical;
2242 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2243 logical = em->block_start;
2244 failrec->bio_flags = EXTENT_BIO_COMPRESSED;
2245 extent_set_compress_type(&failrec->bio_flags,
2246 em->compress_type);
2247 }
2248
2249 btrfs_debug(fs_info,
2250 "Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu",
2251 logical, start, failrec->len);
2252
2253 failrec->logical = logical;
2254 free_extent_map(em);
2255
2256 /* set the bits in the private failure tree */
2257 ret = set_extent_bits(failure_tree, start, end,
2258 EXTENT_LOCKED | EXTENT_DIRTY);
2259 if (ret >= 0)
2260 ret = set_state_failrec(failure_tree, start, failrec);
2261 /* set the bits in the inode's tree */
2262 if (ret >= 0)
2263 ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED);
2264 if (ret < 0) {
2265 kfree(failrec);
2266 return ret;
2267 }
2268 } else {
2269 btrfs_debug(fs_info,
2270 "Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d",
2271 failrec->logical, failrec->start, failrec->len,
2272 failrec->in_validation);
2273 /*
2274 * when data can be on disk more than twice, add to failrec here
2275 * (e.g. with a list for failed_mirror) to make
2276 * clean_io_failure() clean all those errors at once.
2277 */
2278 }
2279
2280 *failrec_ret = failrec;
2281
2282 return 0;
2283 }
2284
2285 int btrfs_check_repairable(struct inode *inode, struct bio *failed_bio,
2286 struct io_failure_record *failrec, int failed_mirror)
2287 {
2288 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2289 int num_copies;
2290
2291 num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
2292 if (num_copies == 1) {
2293 /*
2294 * we only have a single copy of the data, so don't bother with
2295 * all the retry and error correction code that follows. no
2296 * matter what the error is, it is very likely to persist.
2297 */
2298 btrfs_debug(fs_info,
2299 "Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
2300 num_copies, failrec->this_mirror, failed_mirror);
2301 return 0;
2302 }
2303
2304 /*
2305 * there are two premises:
2306 * a) deliver good data to the caller
2307 * b) correct the bad sectors on disk
2308 */
2309 if (failed_bio->bi_vcnt > 1) {
2310 /*
2311 * to fulfill b), we need to know the exact failing sectors, as
2312 * we don't want to rewrite any more than the failed ones. thus,
2313 * we need separate read requests for the failed bio
2314 *
2315 * if the following BUG_ON triggers, our validation request got
2316 * merged. we need separate requests for our algorithm to work.
2317 */
2318 BUG_ON(failrec->in_validation);
2319 failrec->in_validation = 1;
2320 failrec->this_mirror = failed_mirror;
2321 } else {
2322 /*
2323 * we're ready to fulfill a) and b) alongside. get a good copy
2324 * of the failed sector and if we succeed, we have setup
2325 * everything for repair_io_failure to do the rest for us.
2326 */
2327 if (failrec->in_validation) {
2328 BUG_ON(failrec->this_mirror != failed_mirror);
2329 failrec->in_validation = 0;
2330 failrec->this_mirror = 0;
2331 }
2332 failrec->failed_mirror = failed_mirror;
2333 failrec->this_mirror++;
2334 if (failrec->this_mirror == failed_mirror)
2335 failrec->this_mirror++;
2336 }
2337
2338 if (failrec->this_mirror > num_copies) {
2339 btrfs_debug(fs_info,
2340 "Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
2341 num_copies, failrec->this_mirror, failed_mirror);
2342 return 0;
2343 }
2344
2345 return 1;
2346 }
2347
2348
2349 struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
2350 struct io_failure_record *failrec,
2351 struct page *page, int pg_offset, int icsum,
2352 bio_end_io_t *endio_func, void *data)
2353 {
2354 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2355 struct bio *bio;
2356 struct btrfs_io_bio *btrfs_failed_bio;
2357 struct btrfs_io_bio *btrfs_bio;
2358
2359 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2360 if (!bio)
2361 return NULL;
2362
2363 bio->bi_end_io = endio_func;
2364 bio->bi_iter.bi_sector = failrec->logical >> 9;
2365 bio->bi_bdev = fs_info->fs_devices->latest_bdev;
2366 bio->bi_iter.bi_size = 0;
2367 bio->bi_private = data;
2368
2369 btrfs_failed_bio = btrfs_io_bio(failed_bio);
2370 if (btrfs_failed_bio->csum) {
2371 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
2372
2373 btrfs_bio = btrfs_io_bio(bio);
2374 btrfs_bio->csum = btrfs_bio->csum_inline;
2375 icsum *= csum_size;
2376 memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
2377 csum_size);
2378 }
2379
2380 bio_add_page(bio, page, failrec->len, pg_offset);
2381
2382 return bio;
2383 }
2384
2385 /*
2386 * this is a generic handler for readpage errors (default
2387 * readpage_io_failed_hook). if other copies exist, read those and write back
2388 * good data to the failed position. does not investigate in remapping the
2389 * failed extent elsewhere, hoping the device will be smart enough to do this as
2390 * needed
2391 */
2392
2393 static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
2394 struct page *page, u64 start, u64 end,
2395 int failed_mirror)
2396 {
2397 struct io_failure_record *failrec;
2398 struct inode *inode = page->mapping->host;
2399 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2400 struct bio *bio;
2401 int read_mode = 0;
2402 blk_status_t status;
2403 int ret;
2404
2405 BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
2406
2407 ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
2408 if (ret)
2409 return ret;
2410
2411 ret = btrfs_check_repairable(inode, failed_bio, failrec, failed_mirror);
2412 if (!ret) {
2413 free_io_failure(BTRFS_I(inode), failrec);
2414 return -EIO;
2415 }
2416
2417 if (failed_bio->bi_vcnt > 1)
2418 read_mode |= REQ_FAILFAST_DEV;
2419
2420 phy_offset >>= inode->i_sb->s_blocksize_bits;
2421 bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
2422 start - page_offset(page),
2423 (int)phy_offset, failed_bio->bi_end_io,
2424 NULL);
2425 if (!bio) {
2426 free_io_failure(BTRFS_I(inode), failrec);
2427 return -EIO;
2428 }
2429 bio_set_op_attrs(bio, REQ_OP_READ, read_mode);
2430
2431 btrfs_debug(btrfs_sb(inode->i_sb),
2432 "Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d",
2433 read_mode, failrec->this_mirror, failrec->in_validation);
2434
2435 status = tree->ops->submit_bio_hook(inode, bio, failrec->this_mirror,
2436 failrec->bio_flags, 0);
2437 if (status) {
2438 free_io_failure(BTRFS_I(inode), failrec);
2439 bio_put(bio);
2440 ret = blk_status_to_errno(status);
2441 }
2442
2443 return ret;
2444 }
2445
2446 /* lots and lots of room for performance fixes in the end_bio funcs */
2447
2448 void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
2449 {
2450 int uptodate = (err == 0);
2451 struct extent_io_tree *tree;
2452 int ret = 0;
2453
2454 tree = &BTRFS_I(page->mapping->host)->io_tree;
2455
2456 if (tree->ops && tree->ops->writepage_end_io_hook)
2457 tree->ops->writepage_end_io_hook(page, start, end, NULL,
2458 uptodate);
2459
2460 if (!uptodate) {
2461 ClearPageUptodate(page);
2462 SetPageError(page);
2463 ret = ret < 0 ? ret : -EIO;
2464 mapping_set_error(page->mapping, ret);
2465 }
2466 }
2467
2468 /*
2469 * after a writepage IO is done, we need to:
2470 * clear the uptodate bits on error
2471 * clear the writeback bits in the extent tree for this IO
2472 * end_page_writeback if the page has no more pending IO
2473 *
2474 * Scheduling is not allowed, so the extent state tree is expected
2475 * to have one and only one object corresponding to this IO.
2476 */
2477 static void end_bio_extent_writepage(struct bio *bio)
2478 {
2479 int error = blk_status_to_errno(bio->bi_status);
2480 struct bio_vec *bvec;
2481 u64 start;
2482 u64 end;
2483 int i;
2484
2485 bio_for_each_segment_all(bvec, bio, i) {
2486 struct page *page = bvec->bv_page;
2487 struct inode *inode = page->mapping->host;
2488 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2489
2490 /* We always issue full-page reads, but if some block
2491 * in a page fails to read, blk_update_request() will
2492 * advance bv_offset and adjust bv_len to compensate.
2493 * Print a warning for nonzero offsets, and an error
2494 * if they don't add up to a full page. */
2495 if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2496 if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2497 btrfs_err(fs_info,
2498 "partial page write in btrfs with offset %u and length %u",
2499 bvec->bv_offset, bvec->bv_len);
2500 else
2501 btrfs_info(fs_info,
2502 "incomplete page write in btrfs with offset %u and length %u",
2503 bvec->bv_offset, bvec->bv_len);
2504 }
2505
2506 start = page_offset(page);
2507 end = start + bvec->bv_offset + bvec->bv_len - 1;
2508
2509 end_extent_writepage(page, error, start, end);
2510 end_page_writeback(page);
2511 }
2512
2513 bio_put(bio);
2514 }
2515
2516 static void
2517 endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
2518 int uptodate)
2519 {
2520 struct extent_state *cached = NULL;
2521 u64 end = start + len - 1;
2522
2523 if (uptodate && tree->track_uptodate)
2524 set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
2525 unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
2526 }
2527
2528 /*
2529 * after a readpage IO is done, we need to:
2530 * clear the uptodate bits on error
2531 * set the uptodate bits if things worked
2532 * set the page up to date if all extents in the tree are uptodate
2533 * clear the lock bit in the extent tree
2534 * unlock the page if there are no other extents locked for it
2535 *
2536 * Scheduling is not allowed, so the extent state tree is expected
2537 * to have one and only one object corresponding to this IO.
2538 */
2539 static void end_bio_extent_readpage(struct bio *bio)
2540 {
2541 struct bio_vec *bvec;
2542 int uptodate = !bio->bi_status;
2543 struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2544 struct extent_io_tree *tree;
2545 u64 offset = 0;
2546 u64 start;
2547 u64 end;
2548 u64 len;
2549 u64 extent_start = 0;
2550 u64 extent_len = 0;
2551 int mirror;
2552 int ret;
2553 int i;
2554
2555 bio_for_each_segment_all(bvec, bio, i) {
2556 struct page *page = bvec->bv_page;
2557 struct inode *inode = page->mapping->host;
2558 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2559
2560 btrfs_debug(fs_info,
2561 "end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
2562 (u64)bio->bi_iter.bi_sector, bio->bi_status,
2563 io_bio->mirror_num);
2564 tree = &BTRFS_I(inode)->io_tree;
2565
2566 /* We always issue full-page reads, but if some block
2567 * in a page fails to read, blk_update_request() will
2568 * advance bv_offset and adjust bv_len to compensate.
2569 * Print a warning for nonzero offsets, and an error
2570 * if they don't add up to a full page. */
2571 if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2572 if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2573 btrfs_err(fs_info,
2574 "partial page read in btrfs with offset %u and length %u",
2575 bvec->bv_offset, bvec->bv_len);
2576 else
2577 btrfs_info(fs_info,
2578 "incomplete page read in btrfs with offset %u and length %u",
2579 bvec->bv_offset, bvec->bv_len);
2580 }
2581
2582 start = page_offset(page);
2583 end = start + bvec->bv_offset + bvec->bv_len - 1;
2584 len = bvec->bv_len;
2585
2586 mirror = io_bio->mirror_num;
2587 if (likely(uptodate && tree->ops)) {
2588 ret = tree->ops->readpage_end_io_hook(io_bio, offset,
2589 page, start, end,
2590 mirror);
2591 if (ret)
2592 uptodate = 0;
2593 else
2594 clean_io_failure(BTRFS_I(inode), start,
2595 page, 0);
2596 }
2597
2598 if (likely(uptodate))
2599 goto readpage_ok;
2600
2601 if (tree->ops) {
2602 ret = tree->ops->readpage_io_failed_hook(page, mirror);
2603 if (ret == -EAGAIN) {
2604 /*
2605 * Data inode's readpage_io_failed_hook() always
2606 * returns -EAGAIN.
2607 *
2608 * The generic bio_readpage_error handles errors
2609 * the following way: If possible, new read
2610 * requests are created and submitted and will
2611 * end up in end_bio_extent_readpage as well (if
2612 * we're lucky, not in the !uptodate case). In
2613 * that case it returns 0 and we just go on with
2614 * the next page in our bio. If it can't handle
2615 * the error it will return -EIO and we remain
2616 * responsible for that page.
2617 */
2618 ret = bio_readpage_error(bio, offset, page,
2619 start, end, mirror);
2620 if (ret == 0) {
2621 uptodate = !bio->bi_status;
2622 offset += len;
2623 continue;
2624 }
2625 }
2626
2627 /*
2628 * metadata's readpage_io_failed_hook() always returns
2629 * -EIO and fixes nothing. -EIO is also returned if
2630 * data inode error could not be fixed.
2631 */
2632 ASSERT(ret == -EIO);
2633 }
2634 readpage_ok:
2635 if (likely(uptodate)) {
2636 loff_t i_size = i_size_read(inode);
2637 pgoff_t end_index = i_size >> PAGE_SHIFT;
2638 unsigned off;
2639
2640 /* Zero out the end if this page straddles i_size */
2641 off = i_size & (PAGE_SIZE-1);
2642 if (page->index == end_index && off)
2643 zero_user_segment(page, off, PAGE_SIZE);
2644 SetPageUptodate(page);
2645 } else {
2646 ClearPageUptodate(page);
2647 SetPageError(page);
2648 }
2649 unlock_page(page);
2650 offset += len;
2651
2652 if (unlikely(!uptodate)) {
2653 if (extent_len) {
2654 endio_readpage_release_extent(tree,
2655 extent_start,
2656 extent_len, 1);
2657 extent_start = 0;
2658 extent_len = 0;
2659 }
2660 endio_readpage_release_extent(tree, start,
2661 end - start + 1, 0);
2662 } else if (!extent_len) {
2663 extent_start = start;
2664 extent_len = end + 1 - start;
2665 } else if (extent_start + extent_len == start) {
2666 extent_len += end + 1 - start;
2667 } else {
2668 endio_readpage_release_extent(tree, extent_start,
2669 extent_len, uptodate);
2670 extent_start = start;
2671 extent_len = end + 1 - start;
2672 }
2673 }
2674
2675 if (extent_len)
2676 endio_readpage_release_extent(tree, extent_start, extent_len,
2677 uptodate);
2678 if (io_bio->end_io)
2679 io_bio->end_io(io_bio, blk_status_to_errno(bio->bi_status));
2680 bio_put(bio);
2681 }
2682
2683 /*
2684 * this allocates from the btrfs_bioset. We're returning a bio right now
2685 * but you can call btrfs_io_bio for the appropriate container_of magic
2686 */
2687 struct bio *
2688 btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
2689 gfp_t gfp_flags)
2690 {
2691 struct btrfs_io_bio *btrfs_bio;
2692 struct bio *bio;
2693
2694 bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
2695
2696 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2697 while (!bio && (nr_vecs /= 2)) {
2698 bio = bio_alloc_bioset(gfp_flags,
2699 nr_vecs, btrfs_bioset);
2700 }
2701 }
2702
2703 if (bio) {
2704 bio->bi_bdev = bdev;
2705 bio->bi_iter.bi_sector = first_sector;
2706 btrfs_bio = btrfs_io_bio(bio);
2707 btrfs_bio->csum = NULL;
2708 btrfs_bio->csum_allocated = NULL;
2709 btrfs_bio->end_io = NULL;
2710 }
2711 return bio;
2712 }
2713
2714 struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
2715 {
2716 struct btrfs_io_bio *btrfs_bio;
2717 struct bio *new;
2718
2719 new = bio_clone_bioset(bio, gfp_mask, btrfs_bioset);
2720 if (new) {
2721 btrfs_bio = btrfs_io_bio(new);
2722 btrfs_bio->csum = NULL;
2723 btrfs_bio->csum_allocated = NULL;
2724 btrfs_bio->end_io = NULL;
2725 }
2726 return new;
2727 }
2728
2729 /* this also allocates from the btrfs_bioset */
2730 struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
2731 {
2732 struct btrfs_io_bio *btrfs_bio;
2733 struct bio *bio;
2734
2735 bio = bio_alloc_bioset(gfp_mask, nr_iovecs, btrfs_bioset);
2736 if (bio) {
2737 btrfs_bio = btrfs_io_bio(bio);
2738 btrfs_bio->csum = NULL;
2739 btrfs_bio->csum_allocated = NULL;
2740 btrfs_bio->end_io = NULL;
2741 }
2742 return bio;
2743 }
2744
2745
2746 static int __must_check submit_one_bio(struct bio *bio, int mirror_num,
2747 unsigned long bio_flags)
2748 {
2749 blk_status_t ret = 0;
2750 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
2751 struct page *page = bvec->bv_page;
2752 struct extent_io_tree *tree = bio->bi_private;
2753 u64 start;
2754
2755 start = page_offset(page) + bvec->bv_offset;
2756
2757 bio->bi_private = NULL;
2758 bio_get(bio);
2759
2760 if (tree->ops)
2761 ret = tree->ops->submit_bio_hook(page->mapping->host, bio,
2762 mirror_num, bio_flags, start);
2763 else
2764 btrfsic_submit_bio(bio);
2765
2766 bio_put(bio);
2767 return blk_status_to_errno(ret);
2768 }
2769
2770 static int merge_bio(struct extent_io_tree *tree, struct page *page,
2771 unsigned long offset, size_t size, struct bio *bio,
2772 unsigned long bio_flags)
2773 {
2774 int ret = 0;
2775 if (tree->ops)
2776 ret = tree->ops->merge_bio_hook(page, offset, size, bio,
2777 bio_flags);
2778 return ret;
2779
2780 }
2781
2782 static int submit_extent_page(int op, int op_flags, struct extent_io_tree *tree,
2783 struct writeback_control *wbc,
2784 struct page *page, sector_t sector,
2785 size_t size, unsigned long offset,
2786 struct block_device *bdev,
2787 struct bio **bio_ret,
2788 bio_end_io_t end_io_func,
2789 int mirror_num,
2790 unsigned long prev_bio_flags,
2791 unsigned long bio_flags,
2792 bool force_bio_submit)
2793 {
2794 int ret = 0;
2795 struct bio *bio;
2796 int contig = 0;
2797 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2798 size_t page_size = min_t(size_t, size, PAGE_SIZE);
2799
2800 if (bio_ret && *bio_ret) {
2801 bio = *bio_ret;
2802 if (old_compressed)
2803 contig = bio->bi_iter.bi_sector == sector;
2804 else
2805 contig = bio_end_sector(bio) == sector;
2806
2807 if (prev_bio_flags != bio_flags || !contig ||
2808 force_bio_submit ||
2809 merge_bio(tree, page, offset, page_size, bio, bio_flags) ||
2810 bio_add_page(bio, page, page_size, offset) < page_size) {
2811 ret = submit_one_bio(bio, mirror_num, prev_bio_flags);
2812 if (ret < 0) {
2813 *bio_ret = NULL;
2814 return ret;
2815 }
2816 bio = NULL;
2817 } else {
2818 if (wbc)
2819 wbc_account_io(wbc, page, page_size);
2820 return 0;
2821 }
2822 }
2823
2824 bio = btrfs_bio_alloc(bdev, sector, BIO_MAX_PAGES,
2825 GFP_NOFS | __GFP_HIGH);
2826 if (!bio)
2827 return -ENOMEM;
2828
2829 bio_add_page(bio, page, page_size, offset);
2830 bio->bi_end_io = end_io_func;
2831 bio->bi_private = tree;
2832 bio_set_op_attrs(bio, op, op_flags);
2833 if (wbc) {
2834 wbc_init_bio(wbc, bio);
2835 wbc_account_io(wbc, page, page_size);
2836 }
2837
2838 if (bio_ret)
2839 *bio_ret = bio;
2840 else
2841 ret = submit_one_bio(bio, mirror_num, bio_flags);
2842
2843 return ret;
2844 }
2845
2846 static void attach_extent_buffer_page(struct extent_buffer *eb,
2847 struct page *page)
2848 {
2849 if (!PagePrivate(page)) {
2850 SetPagePrivate(page);
2851 get_page(page);
2852 set_page_private(page, (unsigned long)eb);
2853 } else {
2854 WARN_ON(page->private != (unsigned long)eb);
2855 }
2856 }
2857
2858 void set_page_extent_mapped(struct page *page)
2859 {
2860 if (!PagePrivate(page)) {
2861 SetPagePrivate(page);
2862 get_page(page);
2863 set_page_private(page, EXTENT_PAGE_PRIVATE);
2864 }
2865 }
2866
2867 static struct extent_map *
2868 __get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
2869 u64 start, u64 len, get_extent_t *get_extent,
2870 struct extent_map **em_cached)
2871 {
2872 struct extent_map *em;
2873
2874 if (em_cached && *em_cached) {
2875 em = *em_cached;
2876 if (extent_map_in_tree(em) && start >= em->start &&
2877 start < extent_map_end(em)) {
2878 refcount_inc(&em->refs);
2879 return em;
2880 }
2881
2882 free_extent_map(em);
2883 *em_cached = NULL;
2884 }
2885
2886 em = get_extent(BTRFS_I(inode), page, pg_offset, start, len, 0);
2887 if (em_cached && !IS_ERR_OR_NULL(em)) {
2888 BUG_ON(*em_cached);
2889 refcount_inc(&em->refs);
2890 *em_cached = em;
2891 }
2892 return em;
2893 }
2894 /*
2895 * basic readpage implementation. Locked extent state structs are inserted
2896 * into the tree that are removed when the IO is done (by the end_io
2897 * handlers)
2898 * XXX JDM: This needs looking at to ensure proper page locking
2899 * return 0 on success, otherwise return error
2900 */
2901 static int __do_readpage(struct extent_io_tree *tree,
2902 struct page *page,
2903 get_extent_t *get_extent,
2904 struct extent_map **em_cached,
2905 struct bio **bio, int mirror_num,
2906 unsigned long *bio_flags, int read_flags,
2907 u64 *prev_em_start)
2908 {
2909 struct inode *inode = page->mapping->host;
2910 u64 start = page_offset(page);
2911 u64 page_end = start + PAGE_SIZE - 1;
2912 u64 end;
2913 u64 cur = start;
2914 u64 extent_offset;
2915 u64 last_byte = i_size_read(inode);
2916 u64 block_start;
2917 u64 cur_end;
2918 sector_t sector;
2919 struct extent_map *em;
2920 struct block_device *bdev;
2921 int ret = 0;
2922 int nr = 0;
2923 size_t pg_offset = 0;
2924 size_t iosize;
2925 size_t disk_io_size;
2926 size_t blocksize = inode->i_sb->s_blocksize;
2927 unsigned long this_bio_flag = 0;
2928
2929 set_page_extent_mapped(page);
2930
2931 end = page_end;
2932 if (!PageUptodate(page)) {
2933 if (cleancache_get_page(page) == 0) {
2934 BUG_ON(blocksize != PAGE_SIZE);
2935 unlock_extent(tree, start, end);
2936 goto out;
2937 }
2938 }
2939
2940 if (page->index == last_byte >> PAGE_SHIFT) {
2941 char *userpage;
2942 size_t zero_offset = last_byte & (PAGE_SIZE - 1);
2943
2944 if (zero_offset) {
2945 iosize = PAGE_SIZE - zero_offset;
2946 userpage = kmap_atomic(page);
2947 memset(userpage + zero_offset, 0, iosize);
2948 flush_dcache_page(page);
2949 kunmap_atomic(userpage);
2950 }
2951 }
2952 while (cur <= end) {
2953 bool force_bio_submit = false;
2954
2955 if (cur >= last_byte) {
2956 char *userpage;
2957 struct extent_state *cached = NULL;
2958
2959 iosize = PAGE_SIZE - pg_offset;
2960 userpage = kmap_atomic(page);
2961 memset(userpage + pg_offset, 0, iosize);
2962 flush_dcache_page(page);
2963 kunmap_atomic(userpage);
2964 set_extent_uptodate(tree, cur, cur + iosize - 1,
2965 &cached, GFP_NOFS);
2966 unlock_extent_cached(tree, cur,
2967 cur + iosize - 1,
2968 &cached, GFP_NOFS);
2969 break;
2970 }
2971 em = __get_extent_map(inode, page, pg_offset, cur,
2972 end - cur + 1, get_extent, em_cached);
2973 if (IS_ERR_OR_NULL(em)) {
2974 SetPageError(page);
2975 unlock_extent(tree, cur, end);
2976 break;
2977 }
2978 extent_offset = cur - em->start;
2979 BUG_ON(extent_map_end(em) <= cur);
2980 BUG_ON(end < cur);
2981
2982 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2983 this_bio_flag |= EXTENT_BIO_COMPRESSED;
2984 extent_set_compress_type(&this_bio_flag,
2985 em->compress_type);
2986 }
2987
2988 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2989 cur_end = min(extent_map_end(em) - 1, end);
2990 iosize = ALIGN(iosize, blocksize);
2991 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
2992 disk_io_size = em->block_len;
2993 sector = em->block_start >> 9;
2994 } else {
2995 sector = (em->block_start + extent_offset) >> 9;
2996 disk_io_size = iosize;
2997 }
2998 bdev = em->bdev;
2999 block_start = em->block_start;
3000 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
3001 block_start = EXTENT_MAP_HOLE;
3002
3003 /*
3004 * If we have a file range that points to a compressed extent
3005 * and it's followed by a consecutive file range that points to
3006 * to the same compressed extent (possibly with a different
3007 * offset and/or length, so it either points to the whole extent
3008 * or only part of it), we must make sure we do not submit a
3009 * single bio to populate the pages for the 2 ranges because
3010 * this makes the compressed extent read zero out the pages
3011 * belonging to the 2nd range. Imagine the following scenario:
3012 *
3013 * File layout
3014 * [0 - 8K] [8K - 24K]
3015 * | |
3016 * | |
3017 * points to extent X, points to extent X,
3018 * offset 4K, length of 8K offset 0, length 16K
3019 *
3020 * [extent X, compressed length = 4K uncompressed length = 16K]
3021 *
3022 * If the bio to read the compressed extent covers both ranges,
3023 * it will decompress extent X into the pages belonging to the
3024 * first range and then it will stop, zeroing out the remaining
3025 * pages that belong to the other range that points to extent X.
3026 * So here we make sure we submit 2 bios, one for the first
3027 * range and another one for the third range. Both will target
3028 * the same physical extent from disk, but we can't currently
3029 * make the compressed bio endio callback populate the pages
3030 * for both ranges because each compressed bio is tightly
3031 * coupled with a single extent map, and each range can have
3032 * an extent map with a different offset value relative to the
3033 * uncompressed data of our extent and different lengths. This
3034 * is a corner case so we prioritize correctness over
3035 * non-optimal behavior (submitting 2 bios for the same extent).
3036 */
3037 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
3038 prev_em_start && *prev_em_start != (u64)-1 &&
3039 *prev_em_start != em->orig_start)
3040 force_bio_submit = true;
3041
3042 if (prev_em_start)
3043 *prev_em_start = em->orig_start;
3044
3045 free_extent_map(em);
3046 em = NULL;
3047
3048 /* we've found a hole, just zero and go on */
3049 if (block_start == EXTENT_MAP_HOLE) {
3050 char *userpage;
3051 struct extent_state *cached = NULL;
3052
3053 userpage = kmap_atomic(page);
3054 memset(userpage + pg_offset, 0, iosize);
3055 flush_dcache_page(page);
3056 kunmap_atomic(userpage);
3057
3058 set_extent_uptodate(tree, cur, cur + iosize - 1,
3059 &cached, GFP_NOFS);
3060 unlock_extent_cached(tree, cur,
3061 cur + iosize - 1,
3062 &cached, GFP_NOFS);
3063 cur = cur + iosize;
3064 pg_offset += iosize;
3065 continue;
3066 }
3067 /* the get_extent function already copied into the page */
3068 if (test_range_bit(tree, cur, cur_end,
3069 EXTENT_UPTODATE, 1, NULL)) {
3070 check_page_uptodate(tree, page);
3071 unlock_extent(tree, cur, cur + iosize - 1);
3072 cur = cur + iosize;
3073 pg_offset += iosize;
3074 continue;
3075 }
3076 /* we have an inline extent but it didn't get marked up
3077 * to date. Error out
3078 */
3079 if (block_start == EXTENT_MAP_INLINE) {
3080 SetPageError(page);
3081 unlock_extent(tree, cur, cur + iosize - 1);
3082 cur = cur + iosize;
3083 pg_offset += iosize;
3084 continue;
3085 }
3086
3087 ret = submit_extent_page(REQ_OP_READ, read_flags, tree, NULL,
3088 page, sector, disk_io_size, pg_offset,
3089 bdev, bio,
3090 end_bio_extent_readpage, mirror_num,
3091 *bio_flags,
3092 this_bio_flag,
3093 force_bio_submit);
3094 if (!ret) {
3095 nr++;
3096 *bio_flags = this_bio_flag;
3097 } else {
3098 SetPageError(page);
3099 unlock_extent(tree, cur, cur + iosize - 1);
3100 goto out;
3101 }
3102 cur = cur + iosize;
3103 pg_offset += iosize;
3104 }
3105 out:
3106 if (!nr) {
3107 if (!PageError(page))
3108 SetPageUptodate(page);
3109 unlock_page(page);
3110 }
3111 return ret;
3112 }
3113
3114 static inline void __do_contiguous_readpages(struct extent_io_tree *tree,
3115 struct page *pages[], int nr_pages,
3116 u64 start, u64 end,
3117 get_extent_t *get_extent,
3118 struct extent_map **em_cached,
3119 struct bio **bio, int mirror_num,
3120 unsigned long *bio_flags,
3121 u64 *prev_em_start)
3122 {
3123 struct inode *inode;
3124 struct btrfs_ordered_extent *ordered;
3125 int index;
3126
3127 inode = pages[0]->mapping->host;
3128 while (1) {
3129 lock_extent(tree, start, end);
3130 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
3131 end - start + 1);
3132 if (!ordered)
3133 break;
3134 unlock_extent(tree, start, end);
3135 btrfs_start_ordered_extent(inode, ordered, 1);
3136 btrfs_put_ordered_extent(ordered);
3137 }
3138
3139 for (index = 0; index < nr_pages; index++) {
3140 __do_readpage(tree, pages[index], get_extent, em_cached, bio,
3141 mirror_num, bio_flags, 0, prev_em_start);
3142 put_page(pages[index]);
3143 }
3144 }
3145
3146 static void __extent_readpages(struct extent_io_tree *tree,
3147 struct page *pages[],
3148 int nr_pages, get_extent_t *get_extent,
3149 struct extent_map **em_cached,
3150 struct bio **bio, int mirror_num,
3151 unsigned long *bio_flags,
3152 u64 *prev_em_start)
3153 {
3154 u64 start = 0;
3155 u64 end = 0;
3156 u64 page_start;
3157 int index;
3158 int first_index = 0;
3159
3160 for (index = 0; index < nr_pages; index++) {
3161 page_start = page_offset(pages[index]);
3162 if (!end) {
3163 start = page_start;
3164 end = start + PAGE_SIZE - 1;
3165 first_index = index;
3166 } else if (end + 1 == page_start) {
3167 end += PAGE_SIZE;
3168 } else {
3169 __do_contiguous_readpages(tree, &pages[first_index],
3170 index - first_index, start,
3171 end, get_extent, em_cached,
3172 bio, mirror_num, bio_flags,
3173 prev_em_start);
3174 start = page_start;
3175 end = start + PAGE_SIZE - 1;
3176 first_index = index;
3177 }
3178 }
3179
3180 if (end)
3181 __do_contiguous_readpages(tree, &pages[first_index],
3182 index - first_index, start,
3183 end, get_extent, em_cached, bio,
3184 mirror_num, bio_flags,
3185 prev_em_start);
3186 }
3187
3188 static int __extent_read_full_page(struct extent_io_tree *tree,
3189 struct page *page,
3190 get_extent_t *get_extent,
3191 struct bio **bio, int mirror_num,
3192 unsigned long *bio_flags, int read_flags)
3193 {
3194 struct inode *inode = page->mapping->host;
3195 struct btrfs_ordered_extent *ordered;
3196 u64 start = page_offset(page);
3197 u64 end = start + PAGE_SIZE - 1;
3198 int ret;
3199
3200 while (1) {
3201 lock_extent(tree, start, end);
3202 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
3203 PAGE_SIZE);
3204 if (!ordered)
3205 break;
3206 unlock_extent(tree, start, end);
3207 btrfs_start_ordered_extent(inode, ordered, 1);
3208 btrfs_put_ordered_extent(ordered);
3209 }
3210
3211 ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
3212 bio_flags, read_flags, NULL);
3213 return ret;
3214 }
3215
3216 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3217 get_extent_t *get_extent, int mirror_num)
3218 {
3219 struct bio *bio = NULL;
3220 unsigned long bio_flags = 0;
3221 int ret;
3222
3223 ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3224 &bio_flags, 0);
3225 if (bio)
3226 ret = submit_one_bio(bio, mirror_num, bio_flags);
3227 return ret;
3228 }
3229
3230 static void update_nr_written(struct writeback_control *wbc,
3231 unsigned long nr_written)
3232 {
3233 wbc->nr_to_write -= nr_written;
3234 }
3235
3236 /*
3237 * helper for __extent_writepage, doing all of the delayed allocation setup.
3238 *
3239 * This returns 1 if our fill_delalloc function did all the work required
3240 * to write the page (copy into inline extent). In this case the IO has
3241 * been started and the page is already unlocked.
3242 *
3243 * This returns 0 if all went well (page still locked)
3244 * This returns < 0 if there were errors (page still locked)
3245 */
3246 static noinline_for_stack int writepage_delalloc(struct inode *inode,
3247 struct page *page, struct writeback_control *wbc,
3248 struct extent_page_data *epd,
3249 u64 delalloc_start,
3250 unsigned long *nr_written)
3251 {
3252 struct extent_io_tree *tree = epd->tree;
3253 u64 page_end = delalloc_start + PAGE_SIZE - 1;
3254 u64 nr_delalloc;
3255 u64 delalloc_to_write = 0;
3256 u64 delalloc_end = 0;
3257 int ret;
3258 int page_started = 0;
3259
3260 if (epd->extent_locked || !tree->ops || !tree->ops->fill_delalloc)
3261 return 0;
3262
3263 while (delalloc_end < page_end) {
3264 nr_delalloc = find_lock_delalloc_range(inode, tree,
3265 page,
3266 &delalloc_start,
3267 &delalloc_end,
3268 BTRFS_MAX_EXTENT_SIZE);
3269 if (nr_delalloc == 0) {
3270 delalloc_start = delalloc_end + 1;
3271 continue;
3272 }
3273 ret = tree->ops->fill_delalloc(inode, page,
3274 delalloc_start,
3275 delalloc_end,
3276 &page_started,
3277 nr_written);
3278 /* File system has been set read-only */
3279 if (ret) {
3280 SetPageError(page);
3281 /* fill_delalloc should be return < 0 for error
3282 * but just in case, we use > 0 here meaning the
3283 * IO is started, so we don't want to return > 0
3284 * unless things are going well.
3285 */
3286 ret = ret < 0 ? ret : -EIO;
3287 goto done;
3288 }
3289 /*
3290 * delalloc_end is already one less than the total length, so
3291 * we don't subtract one from PAGE_SIZE
3292 */
3293 delalloc_to_write += (delalloc_end - delalloc_start +
3294 PAGE_SIZE) >> PAGE_SHIFT;
3295 delalloc_start = delalloc_end + 1;
3296 }
3297 if (wbc->nr_to_write < delalloc_to_write) {
3298 int thresh = 8192;
3299
3300 if (delalloc_to_write < thresh * 2)
3301 thresh = delalloc_to_write;
3302 wbc->nr_to_write = min_t(u64, delalloc_to_write,
3303 thresh);
3304 }
3305
3306 /* did the fill delalloc function already unlock and start
3307 * the IO?
3308 */
3309 if (page_started) {
3310 /*
3311 * we've unlocked the page, so we can't update
3312 * the mapping's writeback index, just update
3313 * nr_to_write.
3314 */
3315 wbc->nr_to_write -= *nr_written;
3316 return 1;
3317 }
3318
3319 ret = 0;
3320
3321 done:
3322 return ret;
3323 }
3324
3325 /*
3326 * helper for __extent_writepage. This calls the writepage start hooks,
3327 * and does the loop to map the page into extents and bios.
3328 *
3329 * We return 1 if the IO is started and the page is unlocked,
3330 * 0 if all went well (page still locked)
3331 * < 0 if there were errors (page still locked)
3332 */
3333 static noinline_for_stack int __extent_writepage_io(struct inode *inode,
3334 struct page *page,
3335 struct writeback_control *wbc,
3336 struct extent_page_data *epd,
3337 loff_t i_size,
3338 unsigned long nr_written,
3339 int write_flags, int *nr_ret)
3340 {
3341 struct extent_io_tree *tree = epd->tree;
3342 u64 start = page_offset(page);
3343 u64 page_end = start + PAGE_SIZE - 1;
3344 u64 end;
3345 u64 cur = start;
3346 u64 extent_offset;
3347 u64 block_start;
3348 u64 iosize;
3349 sector_t sector;
3350 struct extent_map *em;
3351 struct block_device *bdev;
3352 size_t pg_offset = 0;
3353 size_t blocksize;
3354 int ret = 0;
3355 int nr = 0;
3356 bool compressed;
3357
3358 if (tree->ops && tree->ops->writepage_start_hook) {
3359 ret = tree->ops->writepage_start_hook(page, start,
3360 page_end);
3361 if (ret) {
3362 /* Fixup worker will requeue */
3363 if (ret == -EBUSY)
3364 wbc->pages_skipped++;
3365 else
3366 redirty_page_for_writepage(wbc, page);
3367
3368 update_nr_written(wbc, nr_written);
3369 unlock_page(page);
3370 return 1;
3371 }
3372 }
3373
3374 /*
3375 * we don't want to touch the inode after unlocking the page,
3376 * so we update the mapping writeback index now
3377 */
3378 update_nr_written(wbc, nr_written + 1);
3379
3380 end = page_end;
3381 if (i_size <= start) {
3382 if (tree->ops && tree->ops->writepage_end_io_hook)
3383 tree->ops->writepage_end_io_hook(page, start,
3384 page_end, NULL, 1);
3385 goto done;
3386 }
3387
3388 blocksize = inode->i_sb->s_blocksize;
3389
3390 while (cur <= end) {
3391 u64 em_end;
3392
3393 if (cur >= i_size) {
3394 if (tree->ops && tree->ops->writepage_end_io_hook)
3395 tree->ops->writepage_end_io_hook(page, cur,
3396 page_end, NULL, 1);
3397 break;
3398 }
3399 em = epd->get_extent(BTRFS_I(inode), page, pg_offset, cur,
3400 end - cur + 1, 1);
3401 if (IS_ERR_OR_NULL(em)) {
3402 SetPageError(page);
3403 ret = PTR_ERR_OR_ZERO(em);
3404 break;
3405 }
3406
3407 extent_offset = cur - em->start;
3408 em_end = extent_map_end(em);
3409 BUG_ON(em_end <= cur);
3410 BUG_ON(end < cur);
3411 iosize = min(em_end - cur, end - cur + 1);
3412 iosize = ALIGN(iosize, blocksize);
3413 sector = (em->block_start + extent_offset) >> 9;
3414 bdev = em->bdev;
3415 block_start = em->block_start;
3416 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3417 free_extent_map(em);
3418 em = NULL;
3419
3420 /*
3421 * compressed and inline extents are written through other
3422 * paths in the FS
3423 */
3424 if (compressed || block_start == EXTENT_MAP_HOLE ||
3425 block_start == EXTENT_MAP_INLINE) {
3426 /*
3427 * end_io notification does not happen here for
3428 * compressed extents
3429 */
3430 if (!compressed && tree->ops &&
3431 tree->ops->writepage_end_io_hook)
3432 tree->ops->writepage_end_io_hook(page, cur,
3433 cur + iosize - 1,
3434 NULL, 1);
3435 else if (compressed) {
3436 /* we don't want to end_page_writeback on
3437 * a compressed extent. this happens
3438 * elsewhere
3439 */
3440 nr++;
3441 }
3442
3443 cur += iosize;
3444 pg_offset += iosize;
3445 continue;
3446 }
3447
3448 set_range_writeback(tree, cur, cur + iosize - 1);
3449 if (!PageWriteback(page)) {
3450 btrfs_err(BTRFS_I(inode)->root->fs_info,
3451 "page %lu not writeback, cur %llu end %llu",
3452 page->index, cur, end);
3453 }
3454
3455 ret = submit_extent_page(REQ_OP_WRITE, write_flags, tree, wbc,
3456 page, sector, iosize, pg_offset,
3457 bdev, &epd->bio,
3458 end_bio_extent_writepage,
3459 0, 0, 0, false);
3460 if (ret) {
3461 SetPageError(page);
3462 if (PageWriteback(page))
3463 end_page_writeback(page);
3464 }
3465
3466 cur = cur + iosize;
3467 pg_offset += iosize;
3468 nr++;
3469 }
3470 done:
3471 *nr_ret = nr;
3472 return ret;
3473 }
3474
3475 /*
3476 * the writepage semantics are similar to regular writepage. extent
3477 * records are inserted to lock ranges in the tree, and as dirty areas
3478 * are found, they are marked writeback. Then the lock bits are removed
3479 * and the end_io handler clears the writeback ranges
3480 */
3481 static int __extent_writepage(struct page *page, struct writeback_control *wbc,
3482 void *data)
3483 {
3484 struct inode *inode = page->mapping->host;
3485 struct extent_page_data *epd = data;
3486 u64 start = page_offset(page);
3487 u64 page_end = start + PAGE_SIZE - 1;
3488 int ret;
3489 int nr = 0;
3490 size_t pg_offset = 0;
3491 loff_t i_size = i_size_read(inode);
3492 unsigned long end_index = i_size >> PAGE_SHIFT;
3493 int write_flags = 0;
3494 unsigned long nr_written = 0;
3495
3496 if (wbc->sync_mode == WB_SYNC_ALL)
3497 write_flags = REQ_SYNC;
3498
3499 trace___extent_writepage(page, inode, wbc);
3500
3501 WARN_ON(!PageLocked(page));
3502
3503 ClearPageError(page);
3504
3505 pg_offset = i_size & (PAGE_SIZE - 1);
3506 if (page->index > end_index ||
3507 (page->index == end_index && !pg_offset)) {
3508 page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
3509 unlock_page(page);
3510 return 0;
3511 }
3512
3513 if (page->index == end_index) {
3514 char *userpage;
3515
3516 userpage = kmap_atomic(page);
3517 memset(userpage + pg_offset, 0,
3518 PAGE_SIZE - pg_offset);
3519 kunmap_atomic(userpage);
3520 flush_dcache_page(page);
3521 }
3522
3523 pg_offset = 0;
3524
3525 set_page_extent_mapped(page);
3526
3527 ret = writepage_delalloc(inode, page, wbc, epd, start, &nr_written);
3528 if (ret == 1)
3529 goto done_unlocked;
3530 if (ret)
3531 goto done;
3532
3533 ret = __extent_writepage_io(inode, page, wbc, epd,
3534 i_size, nr_written, write_flags, &nr);
3535 if (ret == 1)
3536 goto done_unlocked;
3537
3538 done:
3539 if (nr == 0) {
3540 /* make sure the mapping tag for page dirty gets cleared */
3541 set_page_writeback(page);
3542 end_page_writeback(page);
3543 }
3544 if (PageError(page)) {
3545 ret = ret < 0 ? ret : -EIO;
3546 end_extent_writepage(page, ret, start, page_end);
3547 }
3548 unlock_page(page);
3549 return ret;
3550
3551 done_unlocked:
3552 return 0;
3553 }
3554
3555 void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3556 {
3557 wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
3558 TASK_UNINTERRUPTIBLE);
3559 }
3560
3561 static noinline_for_stack int
3562 lock_extent_buffer_for_io(struct extent_buffer *eb,
3563 struct btrfs_fs_info *fs_info,
3564 struct extent_page_data *epd)
3565 {
3566 unsigned long i, num_pages;
3567 int flush = 0;
3568 int ret = 0;
3569
3570 if (!btrfs_try_tree_write_lock(eb)) {
3571 flush = 1;
3572 flush_write_bio(epd);
3573 btrfs_tree_lock(eb);
3574 }
3575
3576 if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
3577 btrfs_tree_unlock(eb);
3578 if (!epd->sync_io)
3579 return 0;
3580 if (!flush) {
3581 flush_write_bio(epd);
3582 flush = 1;
3583 }
3584 while (1) {
3585 wait_on_extent_buffer_writeback(eb);
3586 btrfs_tree_lock(eb);
3587 if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
3588 break;
3589 btrfs_tree_unlock(eb);
3590 }
3591 }
3592
3593 /*
3594 * We need to do this to prevent races in people who check if the eb is
3595 * under IO since we can end up having no IO bits set for a short period
3596 * of time.
3597 */
3598 spin_lock(&eb->refs_lock);
3599 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3600 set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3601 spin_unlock(&eb->refs_lock);
3602 btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3603 __percpu_counter_add(&fs_info->dirty_metadata_bytes,
3604 -eb->len,
3605 fs_info->dirty_metadata_batch);
3606 ret = 1;
3607 } else {
3608 spin_unlock(&eb->refs_lock);
3609 }
3610
3611 btrfs_tree_unlock(eb);
3612
3613 if (!ret)
3614 return ret;
3615
3616 num_pages = num_extent_pages(eb->start, eb->len);
3617 for (i = 0; i < num_pages; i++) {
3618 struct page *p = eb->pages[i];
3619
3620 if (!trylock_page(p)) {
3621 if (!flush) {
3622 flush_write_bio(epd);
3623 flush = 1;
3624 }
3625 lock_page(p);
3626 }
3627 }
3628
3629 return ret;
3630 }
3631
3632 static void end_extent_buffer_writeback(struct extent_buffer *eb)
3633 {
3634 clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3635 smp_mb__after_atomic();
3636 wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
3637 }
3638
3639 static void set_btree_ioerr(struct page *page)
3640 {
3641 struct extent_buffer *eb = (struct extent_buffer *)page->private;
3642
3643 SetPageError(page);
3644 if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
3645 return;
3646
3647 /*
3648 * If writeback for a btree extent that doesn't belong to a log tree
3649 * failed, increment the counter transaction->eb_write_errors.
3650 * We do this because while the transaction is running and before it's
3651 * committing (when we call filemap_fdata[write|wait]_range against
3652 * the btree inode), we might have
3653 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
3654 * returns an error or an error happens during writeback, when we're
3655 * committing the transaction we wouldn't know about it, since the pages
3656 * can be no longer dirty nor marked anymore for writeback (if a
3657 * subsequent modification to the extent buffer didn't happen before the
3658 * transaction commit), which makes filemap_fdata[write|wait]_range not
3659 * able to find the pages tagged with SetPageError at transaction
3660 * commit time. So if this happens we must abort the transaction,
3661 * otherwise we commit a super block with btree roots that point to
3662 * btree nodes/leafs whose content on disk is invalid - either garbage
3663 * or the content of some node/leaf from a past generation that got
3664 * cowed or deleted and is no longer valid.
3665 *
3666 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
3667 * not be enough - we need to distinguish between log tree extents vs
3668 * non-log tree extents, and the next filemap_fdatawait_range() call
3669 * will catch and clear such errors in the mapping - and that call might
3670 * be from a log sync and not from a transaction commit. Also, checking
3671 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
3672 * not done and would not be reliable - the eb might have been released
3673 * from memory and reading it back again means that flag would not be
3674 * set (since it's a runtime flag, not persisted on disk).
3675 *
3676 * Using the flags below in the btree inode also makes us achieve the
3677 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
3678 * writeback for all dirty pages and before filemap_fdatawait_range()
3679 * is called, the writeback for all dirty pages had already finished
3680 * with errors - because we were not using AS_EIO/AS_ENOSPC,
3681 * filemap_fdatawait_range() would return success, as it could not know
3682 * that writeback errors happened (the pages were no longer tagged for
3683 * writeback).
3684 */
3685 switch (eb->log_index) {
3686 case -1:
3687 set_bit(BTRFS_FS_BTREE_ERR, &eb->fs_info->flags);
3688 break;
3689 case 0:
3690 set_bit(BTRFS_FS_LOG1_ERR, &eb->fs_info->flags);
3691 break;
3692 case 1:
3693 set_bit(BTRFS_FS_LOG2_ERR, &eb->fs_info->flags);
3694 break;
3695 default:
3696 BUG(); /* unexpected, logic error */
3697 }
3698 }
3699
3700 static void end_bio_extent_buffer_writepage(struct bio *bio)
3701 {
3702 struct bio_vec *bvec;
3703 struct extent_buffer *eb;
3704 int i, done;
3705
3706 bio_for_each_segment_all(bvec, bio, i) {
3707 struct page *page = bvec->bv_page;
3708
3709 eb = (struct extent_buffer *)page->private;
3710 BUG_ON(!eb);
3711 done = atomic_dec_and_test(&eb->io_pages);
3712
3713 if (bio->bi_status ||
3714 test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
3715 ClearPageUptodate(page);
3716 set_btree_ioerr(page);
3717 }
3718
3719 end_page_writeback(page);
3720
3721 if (!done)
3722 continue;
3723
3724 end_extent_buffer_writeback(eb);
3725 }
3726
3727 bio_put(bio);
3728 }
3729
3730 static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3731 struct btrfs_fs_info *fs_info,
3732 struct writeback_control *wbc,
3733 struct extent_page_data *epd)
3734 {
3735 struct block_device *bdev = fs_info->fs_devices->latest_bdev;
3736 struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3737 u64 offset = eb->start;
3738 u32 nritems;
3739 unsigned long i, num_pages;
3740 unsigned long bio_flags = 0;
3741 unsigned long start, end;
3742 int write_flags = (epd->sync_io ? REQ_SYNC : 0) | REQ_META;
3743 int ret = 0;
3744
3745 clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
3746 num_pages = num_extent_pages(eb->start, eb->len);
3747 atomic_set(&eb->io_pages, num_pages);
3748 if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
3749 bio_flags = EXTENT_BIO_TREE_LOG;
3750
3751 /* set btree blocks beyond nritems with 0 to avoid stale content. */
3752 nritems = btrfs_header_nritems(eb);
3753 if (btrfs_header_level(eb) > 0) {
3754 end = btrfs_node_key_ptr_offset(nritems);
3755
3756 memzero_extent_buffer(eb, end, eb->len - end);
3757 } else {
3758 /*
3759 * leaf:
3760 * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
3761 */
3762 start = btrfs_item_nr_offset(nritems);
3763 end = btrfs_leaf_data(eb) + leaf_data_end(fs_info, eb);
3764 memzero_extent_buffer(eb, start, end - start);
3765 }
3766
3767 for (i = 0; i < num_pages; i++) {
3768 struct page *p = eb->pages[i];
3769
3770 clear_page_dirty_for_io(p);
3771 set_page_writeback(p);
3772 ret = submit_extent_page(REQ_OP_WRITE, write_flags, tree, wbc,
3773 p, offset >> 9, PAGE_SIZE, 0, bdev,
3774 &epd->bio,
3775 end_bio_extent_buffer_writepage,
3776 0, epd->bio_flags, bio_flags, false);
3777 epd->bio_flags = bio_flags;
3778 if (ret) {
3779 set_btree_ioerr(p);
3780 if (PageWriteback(p))
3781 end_page_writeback(p);
3782 if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
3783 end_extent_buffer_writeback(eb);
3784 ret = -EIO;
3785 break;
3786 }
3787 offset += PAGE_SIZE;
3788 update_nr_written(wbc, 1);
3789 unlock_page(p);
3790 }
3791
3792 if (unlikely(ret)) {
3793 for (; i < num_pages; i++) {
3794 struct page *p = eb->pages[i];
3795 clear_page_dirty_for_io(p);
3796 unlock_page(p);
3797 }
3798 }
3799
3800 return ret;
3801 }
3802
3803 int btree_write_cache_pages(struct address_space *mapping,
3804 struct writeback_control *wbc)
3805 {
3806 struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
3807 struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
3808 struct extent_buffer *eb, *prev_eb = NULL;
3809 struct extent_page_data epd = {
3810 .bio = NULL,
3811 .tree = tree,
3812 .extent_locked = 0,
3813 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
3814 .bio_flags = 0,
3815 };
3816 int ret = 0;
3817 int done = 0;
3818 int nr_to_write_done = 0;
3819 struct pagevec pvec;
3820 int nr_pages;
3821 pgoff_t index;
3822 pgoff_t end; /* Inclusive */
3823 int scanned = 0;
3824 int tag;
3825
3826 pagevec_init(&pvec, 0);
3827 if (wbc->range_cyclic) {
3828 index = mapping->writeback_index; /* Start from prev offset */
3829 end = -1;
3830 } else {
3831 index = wbc->range_start >> PAGE_SHIFT;
3832 end = wbc->range_end >> PAGE_SHIFT;
3833 scanned = 1;
3834 }
3835 if (wbc->sync_mode == WB_SYNC_ALL)
3836 tag = PAGECACHE_TAG_TOWRITE;
3837 else
3838 tag = PAGECACHE_TAG_DIRTY;
3839 retry:
3840 if (wbc->sync_mode == WB_SYNC_ALL)
3841 tag_pages_for_writeback(mapping, index, end);
3842 while (!done && !nr_to_write_done && (index <= end) &&
3843 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3844 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3845 unsigned i;
3846
3847 scanned = 1;
3848 for (i = 0; i < nr_pages; i++) {
3849 struct page *page = pvec.pages[i];
3850
3851 if (!PagePrivate(page))
3852 continue;
3853
3854 if (!wbc->range_cyclic && page->index > end) {
3855 done = 1;
3856 break;
3857 }
3858
3859 spin_lock(&mapping->private_lock);
3860 if (!PagePrivate(page)) {
3861 spin_unlock(&mapping->private_lock);
3862 continue;
3863 }
3864
3865 eb = (struct extent_buffer *)page->private;
3866
3867 /*
3868 * Shouldn't happen and normally this would be a BUG_ON
3869 * but no sense in crashing the users box for something
3870 * we can survive anyway.
3871 */
3872 if (WARN_ON(!eb)) {
3873 spin_unlock(&mapping->private_lock);
3874 continue;
3875 }
3876
3877 if (eb == prev_eb) {
3878 spin_unlock(&mapping->private_lock);
3879 continue;
3880 }
3881
3882 ret = atomic_inc_not_zero(&eb->refs);
3883 spin_unlock(&mapping->private_lock);
3884 if (!ret)
3885 continue;
3886
3887 prev_eb = eb;
3888 ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
3889 if (!ret) {
3890 free_extent_buffer(eb);
3891 continue;
3892 }
3893
3894 ret = write_one_eb(eb, fs_info, wbc, &epd);
3895 if (ret) {
3896 done = 1;
3897 free_extent_buffer(eb);
3898 break;
3899 }
3900 free_extent_buffer(eb);
3901
3902 /*
3903 * the filesystem may choose to bump up nr_to_write.
3904 * We have to make sure to honor the new nr_to_write
3905 * at any time
3906 */
3907 nr_to_write_done = wbc->nr_to_write <= 0;
3908 }
3909 pagevec_release(&pvec);
3910 cond_resched();
3911 }
3912 if (!scanned && !done) {
3913 /*
3914 * We hit the last page and there is more work to be done: wrap
3915 * back to the start of the file
3916 */
3917 scanned = 1;
3918 index = 0;
3919 goto retry;
3920 }
3921 flush_write_bio(&epd);
3922 return ret;
3923 }
3924
3925 /**
3926 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3927 * @mapping: address space structure to write
3928 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
3929 * @writepage: function called for each page
3930 * @data: data passed to writepage function
3931 *
3932 * If a page is already under I/O, write_cache_pages() skips it, even
3933 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
3934 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
3935 * and msync() need to guarantee that all the data which was dirty at the time
3936 * the call was made get new I/O started against them. If wbc->sync_mode is
3937 * WB_SYNC_ALL then we were called for data integrity and we must wait for
3938 * existing IO to complete.
3939 */
3940 static int extent_write_cache_pages(struct address_space *mapping,
3941 struct writeback_control *wbc,
3942 writepage_t writepage, void *data,
3943 void (*flush_fn)(void *))
3944 {
3945 struct inode *inode = mapping->host;
3946 int ret = 0;
3947 int done = 0;
3948 int nr_to_write_done = 0;
3949 struct pagevec pvec;
3950 int nr_pages;
3951 pgoff_t index;
3952 pgoff_t end; /* Inclusive */
3953 pgoff_t done_index;
3954 int range_whole = 0;
3955 int scanned = 0;
3956 int tag;
3957
3958 /*
3959 * We have to hold onto the inode so that ordered extents can do their
3960 * work when the IO finishes. The alternative to this is failing to add
3961 * an ordered extent if the igrab() fails there and that is a huge pain
3962 * to deal with, so instead just hold onto the inode throughout the
3963 * writepages operation. If it fails here we are freeing up the inode
3964 * anyway and we'd rather not waste our time writing out stuff that is
3965 * going to be truncated anyway.
3966 */
3967 if (!igrab(inode))
3968 return 0;
3969
3970 pagevec_init(&pvec, 0);
3971 if (wbc->range_cyclic) {
3972 index = mapping->writeback_index; /* Start from prev offset */
3973 end = -1;
3974 } else {
3975 index = wbc->range_start >> PAGE_SHIFT;
3976 end = wbc->range_end >> PAGE_SHIFT;
3977 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
3978 range_whole = 1;
3979 scanned = 1;
3980 }
3981 if (wbc->sync_mode == WB_SYNC_ALL)
3982 tag = PAGECACHE_TAG_TOWRITE;
3983 else
3984 tag = PAGECACHE_TAG_DIRTY;
3985 retry:
3986 if (wbc->sync_mode == WB_SYNC_ALL)
3987 tag_pages_for_writeback(mapping, index, end);
3988 done_index = index;
3989 while (!done && !nr_to_write_done && (index <= end) &&
3990 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
3991 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3992 unsigned i;
3993
3994 scanned = 1;
3995 for (i = 0; i < nr_pages; i++) {
3996 struct page *page = pvec.pages[i];
3997
3998 done_index = page->index;
3999 /*
4000 * At this point we hold neither mapping->tree_lock nor
4001 * lock on the page itself: the page may be truncated or
4002 * invalidated (changing page->mapping to NULL), or even
4003 * swizzled back from swapper_space to tmpfs file
4004 * mapping
4005 */
4006 if (!trylock_page(page)) {
4007 flush_fn(data);
4008 lock_page(page);
4009 }
4010
4011 if (unlikely(page->mapping != mapping)) {
4012 unlock_page(page);
4013 continue;
4014 }
4015
4016 if (!wbc->range_cyclic && page->index > end) {
4017 done = 1;
4018 unlock_page(page);
4019 continue;
4020 }
4021
4022 if (wbc->sync_mode != WB_SYNC_NONE) {
4023 if (PageWriteback(page))
4024 flush_fn(data);
4025 wait_on_page_writeback(page);
4026 }
4027
4028 if (PageWriteback(page) ||
4029 !clear_page_dirty_for_io(page)) {
4030 unlock_page(page);
4031 continue;
4032 }
4033
4034 ret = (*writepage)(page, wbc, data);
4035
4036 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
4037 unlock_page(page);
4038 ret = 0;
4039 }
4040 if (ret < 0) {
4041 /*
4042 * done_index is set past this page,
4043 * so media errors will not choke
4044 * background writeout for the entire
4045 * file. This has consequences for
4046 * range_cyclic semantics (ie. it may
4047 * not be suitable for data integrity
4048 * writeout).
4049 */
4050 done_index = page->index + 1;
4051 done = 1;
4052 break;
4053 }
4054
4055 /*
4056 * the filesystem may choose to bump up nr_to_write.
4057 * We have to make sure to honor the new nr_to_write
4058 * at any time
4059 */
4060 nr_to_write_done = wbc->nr_to_write <= 0;
4061 }
4062 pagevec_release(&pvec);
4063 cond_resched();
4064 }
4065 if (!scanned && !done) {
4066 /*
4067 * We hit the last page and there is more work to be done: wrap
4068 * back to the start of the file
4069 */
4070 scanned = 1;
4071 index = 0;
4072 goto retry;
4073 }
4074
4075 if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
4076 mapping->writeback_index = done_index;
4077
4078 btrfs_add_delayed_iput(inode);
4079 return ret;
4080 }
4081
4082 static void flush_epd_write_bio(struct extent_page_data *epd)
4083 {
4084 if (epd->bio) {
4085 int ret;
4086
4087 bio_set_op_attrs(epd->bio, REQ_OP_WRITE,
4088 epd->sync_io ? REQ_SYNC : 0);
4089
4090 ret = submit_one_bio(epd->bio, 0, epd->bio_flags);
4091 BUG_ON(ret < 0); /* -ENOMEM */
4092 epd->bio = NULL;
4093 }
4094 }
4095
4096 static noinline void flush_write_bio(void *data)
4097 {
4098 struct extent_page_data *epd = data;
4099 flush_epd_write_bio(epd);
4100 }
4101
4102 int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
4103 get_extent_t *get_extent,
4104 struct writeback_control *wbc)
4105 {
4106 int ret;
4107 struct extent_page_data epd = {
4108 .bio = NULL,
4109 .tree = tree,
4110 .get_extent = get_extent,
4111 .extent_locked = 0,
4112 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4113 .bio_flags = 0,
4114 };
4115
4116 ret = __extent_writepage(page, wbc, &epd);
4117
4118 flush_epd_write_bio(&epd);
4119 return ret;
4120 }
4121
4122 int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
4123 u64 start, u64 end, get_extent_t *get_extent,
4124 int mode)
4125 {
4126 int ret = 0;
4127 struct address_space *mapping = inode->i_mapping;
4128 struct page *page;
4129 unsigned long nr_pages = (end - start + PAGE_SIZE) >>
4130 PAGE_SHIFT;
4131
4132 struct extent_page_data epd = {
4133 .bio = NULL,
4134 .tree = tree,
4135 .get_extent = get_extent,
4136 .extent_locked = 1,
4137 .sync_io = mode == WB_SYNC_ALL,
4138 .bio_flags = 0,
4139 };
4140 struct writeback_control wbc_writepages = {
4141 .sync_mode = mode,
4142 .nr_to_write = nr_pages * 2,
4143 .range_start = start,
4144 .range_end = end + 1,
4145 };
4146
4147 while (start <= end) {
4148 page = find_get_page(mapping, start >> PAGE_SHIFT);
4149 if (clear_page_dirty_for_io(page))
4150 ret = __extent_writepage(page, &wbc_writepages, &epd);
4151 else {
4152 if (tree->ops && tree->ops->writepage_end_io_hook)
4153 tree->ops->writepage_end_io_hook(page, start,
4154 start + PAGE_SIZE - 1,
4155 NULL, 1);
4156 unlock_page(page);
4157 }
4158 put_page(page);
4159 start += PAGE_SIZE;
4160 }
4161
4162 flush_epd_write_bio(&epd);
4163 return ret;
4164 }
4165
4166 int extent_writepages(struct extent_io_tree *tree,
4167 struct address_space *mapping,
4168 get_extent_t *get_extent,
4169 struct writeback_control *wbc)
4170 {
4171 int ret = 0;
4172 struct extent_page_data epd = {
4173 .bio = NULL,
4174 .tree = tree,
4175 .get_extent = get_extent,
4176 .extent_locked = 0,
4177 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4178 .bio_flags = 0,
4179 };
4180
4181 ret = extent_write_cache_pages(mapping, wbc, __extent_writepage, &epd,
4182 flush_write_bio);
4183 flush_epd_write_bio(&epd);
4184 return ret;
4185 }
4186
4187 int extent_readpages(struct extent_io_tree *tree,
4188 struct address_space *mapping,
4189 struct list_head *pages, unsigned nr_pages,
4190 get_extent_t get_extent)
4191 {
4192 struct bio *bio = NULL;
4193 unsigned page_idx;
4194 unsigned long bio_flags = 0;
4195 struct page *pagepool[16];
4196 struct page *page;
4197 struct extent_map *em_cached = NULL;
4198 int nr = 0;
4199 u64 prev_em_start = (u64)-1;
4200
4201 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
4202 page = list_entry(pages->prev, struct page, lru);
4203
4204 prefetchw(&page->flags);
4205 list_del(&page->lru);
4206 if (add_to_page_cache_lru(page, mapping,
4207 page->index,
4208 readahead_gfp_mask(mapping))) {
4209 put_page(page);
4210 continue;
4211 }
4212
4213 pagepool[nr++] = page;
4214 if (nr < ARRAY_SIZE(pagepool))
4215 continue;
4216 __extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4217 &bio, 0, &bio_flags, &prev_em_start);
4218 nr = 0;
4219 }
4220 if (nr)
4221 __extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4222 &bio, 0, &bio_flags, &prev_em_start);
4223
4224 if (em_cached)
4225 free_extent_map(em_cached);
4226
4227 BUG_ON(!list_empty(pages));
4228 if (bio)
4229 return submit_one_bio(bio, 0, bio_flags);
4230 return 0;
4231 }
4232
4233 /*
4234 * basic invalidatepage code, this waits on any locked or writeback
4235 * ranges corresponding to the page, and then deletes any extent state
4236 * records from the tree
4237 */
4238 int extent_invalidatepage(struct extent_io_tree *tree,
4239 struct page *page, unsigned long offset)
4240 {
4241 struct extent_state *cached_state = NULL;
4242 u64 start = page_offset(page);
4243 u64 end = start + PAGE_SIZE - 1;
4244 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
4245
4246 start += ALIGN(offset, blocksize);
4247 if (start > end)
4248 return 0;
4249
4250 lock_extent_bits(tree, start, end, &cached_state);
4251 wait_on_page_writeback(page);
4252 clear_extent_bit(tree, start, end,
4253 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
4254 EXTENT_DO_ACCOUNTING,
4255 1, 1, &cached_state, GFP_NOFS);
4256 return 0;
4257 }
4258
4259 /*
4260 * a helper for releasepage, this tests for areas of the page that
4261 * are locked or under IO and drops the related state bits if it is safe
4262 * to drop the page.
4263 */
4264 static int try_release_extent_state(struct extent_map_tree *map,
4265 struct extent_io_tree *tree,
4266 struct page *page, gfp_t mask)
4267 {
4268 u64 start = page_offset(page);
4269 u64 end = start + PAGE_SIZE - 1;
4270 int ret = 1;
4271
4272 if (test_range_bit(tree, start, end,
4273 EXTENT_IOBITS, 0, NULL))
4274 ret = 0;
4275 else {
4276 /*
4277 * at this point we can safely clear everything except the
4278 * locked bit and the nodatasum bit
4279 */
4280 ret = clear_extent_bit(tree, start, end,
4281 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
4282 0, 0, NULL, mask);
4283
4284 /* if clear_extent_bit failed for enomem reasons,
4285 * we can't allow the release to continue.
4286 */
4287 if (ret < 0)
4288 ret = 0;
4289 else
4290 ret = 1;
4291 }
4292 return ret;
4293 }
4294
4295 /*
4296 * a helper for releasepage. As long as there are no locked extents
4297 * in the range corresponding to the page, both state records and extent
4298 * map records are removed
4299 */
4300 int try_release_extent_mapping(struct extent_map_tree *map,
4301 struct extent_io_tree *tree, struct page *page,
4302 gfp_t mask)
4303 {
4304 struct extent_map *em;
4305 u64 start = page_offset(page);
4306 u64 end = start + PAGE_SIZE - 1;
4307
4308 if (gfpflags_allow_blocking(mask) &&
4309 page->mapping->host->i_size > SZ_16M) {
4310 u64 len;
4311 while (start <= end) {
4312 len = end - start + 1;
4313 write_lock(&map->lock);
4314 em = lookup_extent_mapping(map, start, len);
4315 if (!em) {
4316 write_unlock(&map->lock);
4317 break;
4318 }
4319 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
4320 em->start != start) {
4321 write_unlock(&map->lock);
4322 free_extent_map(em);
4323 break;
4324 }
4325 if (!test_range_bit(tree, em->start,
4326 extent_map_end(em) - 1,
4327 EXTENT_LOCKED | EXTENT_WRITEBACK,
4328 0, NULL)) {
4329 remove_extent_mapping(map, em);
4330 /* once for the rb tree */
4331 free_extent_map(em);
4332 }
4333 start = extent_map_end(em);
4334 write_unlock(&map->lock);
4335
4336 /* once for us */
4337 free_extent_map(em);
4338 }
4339 }
4340 return try_release_extent_state(map, tree, page, mask);
4341 }
4342
4343 /*
4344 * helper function for fiemap, which doesn't want to see any holes.
4345 * This maps until we find something past 'last'
4346 */
4347 static struct extent_map *get_extent_skip_holes(struct inode *inode,
4348 u64 offset,
4349 u64 last,
4350 get_extent_t *get_extent)
4351 {
4352 u64 sectorsize = btrfs_inode_sectorsize(inode);
4353 struct extent_map *em;
4354 u64 len;
4355
4356 if (offset >= last)
4357 return NULL;
4358
4359 while (1) {
4360 len = last - offset;
4361 if (len == 0)
4362 break;
4363 len = ALIGN(len, sectorsize);
4364 em = get_extent(BTRFS_I(inode), NULL, 0, offset, len, 0);
4365 if (IS_ERR_OR_NULL(em))
4366 return em;
4367
4368 /* if this isn't a hole return it */
4369 if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
4370 em->block_start != EXTENT_MAP_HOLE) {
4371 return em;
4372 }
4373
4374 /* this is a hole, advance to the next extent */
4375 offset = extent_map_end(em);
4376 free_extent_map(em);
4377 if (offset >= last)
4378 break;
4379 }
4380 return NULL;
4381 }
4382
4383 int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4384 __u64 start, __u64 len, get_extent_t *get_extent)
4385 {
4386 int ret = 0;
4387 u64 off = start;
4388 u64 max = start + len;
4389 u32 flags = 0;
4390 u32 found_type;
4391 u64 last;
4392 u64 last_for_get_extent = 0;
4393 u64 disko = 0;
4394 u64 isize = i_size_read(inode);
4395 struct btrfs_key found_key;
4396 struct extent_map *em = NULL;
4397 struct extent_state *cached_state = NULL;
4398 struct btrfs_path *path;
4399 struct btrfs_root *root = BTRFS_I(inode)->root;
4400 int end = 0;
4401 u64 em_start = 0;
4402 u64 em_len = 0;
4403 u64 em_end = 0;
4404
4405 if (len == 0)
4406 return -EINVAL;
4407
4408 path = btrfs_alloc_path();
4409 if (!path)
4410 return -ENOMEM;
4411 path->leave_spinning = 1;
4412
4413 start = round_down(start, btrfs_inode_sectorsize(inode));
4414 len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
4415
4416 /*
4417 * lookup the last file extent. We're not using i_size here
4418 * because there might be preallocation past i_size
4419 */
4420 ret = btrfs_lookup_file_extent(NULL, root, path,
4421 btrfs_ino(BTRFS_I(inode)), -1, 0);
4422 if (ret < 0) {
4423 btrfs_free_path(path);
4424 return ret;
4425 } else {
4426 WARN_ON(!ret);
4427 if (ret == 1)
4428 ret = 0;
4429 }
4430
4431 path->slots[0]--;
4432 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
4433 found_type = found_key.type;
4434
4435 /* No extents, but there might be delalloc bits */
4436 if (found_key.objectid != btrfs_ino(BTRFS_I(inode)) ||
4437 found_type != BTRFS_EXTENT_DATA_KEY) {
4438 /* have to trust i_size as the end */
4439 last = (u64)-1;
4440 last_for_get_extent = isize;
4441 } else {
4442 /*
4443 * remember the start of the last extent. There are a
4444 * bunch of different factors that go into the length of the
4445 * extent, so its much less complex to remember where it started
4446 */
4447 last = found_key.offset;
4448 last_for_get_extent = last + 1;
4449 }
4450 btrfs_release_path(path);
4451
4452 /*
4453 * we might have some extents allocated but more delalloc past those
4454 * extents. so, we trust isize unless the start of the last extent is
4455 * beyond isize
4456 */
4457 if (last < isize) {
4458 last = (u64)-1;
4459 last_for_get_extent = isize;
4460 }
4461
4462 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4463 &cached_state);
4464
4465 em = get_extent_skip_holes(inode, start, last_for_get_extent,
4466 get_extent);
4467 if (!em)
4468 goto out;
4469 if (IS_ERR(em)) {
4470 ret = PTR_ERR(em);
4471 goto out;
4472 }
4473
4474 while (!end) {
4475 u64 offset_in_extent = 0;
4476
4477 /* break if the extent we found is outside the range */
4478 if (em->start >= max || extent_map_end(em) < off)
4479 break;
4480
4481 /*
4482 * get_extent may return an extent that starts before our
4483 * requested range. We have to make sure the ranges
4484 * we return to fiemap always move forward and don't
4485 * overlap, so adjust the offsets here
4486 */
4487 em_start = max(em->start, off);
4488
4489 /*
4490 * record the offset from the start of the extent
4491 * for adjusting the disk offset below. Only do this if the
4492 * extent isn't compressed since our in ram offset may be past
4493 * what we have actually allocated on disk.
4494 */
4495 if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4496 offset_in_extent = em_start - em->start;
4497 em_end = extent_map_end(em);
4498 em_len = em_end - em_start;
4499 disko = 0;
4500 flags = 0;
4501
4502 /*
4503 * bump off for our next call to get_extent
4504 */
4505 off = extent_map_end(em);
4506 if (off >= max)
4507 end = 1;
4508
4509 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
4510 end = 1;
4511 flags |= FIEMAP_EXTENT_LAST;
4512 } else if (em->block_start == EXTENT_MAP_INLINE) {
4513 flags |= (FIEMAP_EXTENT_DATA_INLINE |
4514 FIEMAP_EXTENT_NOT_ALIGNED);
4515 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
4516 flags |= (FIEMAP_EXTENT_DELALLOC |
4517 FIEMAP_EXTENT_UNKNOWN);
4518 } else if (fieinfo->fi_extents_max) {
4519 struct btrfs_trans_handle *trans;
4520
4521 u64 bytenr = em->block_start -
4522 (em->start - em->orig_start);
4523
4524 disko = em->block_start + offset_in_extent;
4525
4526 /*
4527 * We need a trans handle to get delayed refs
4528 */
4529 trans = btrfs_join_transaction(root);
4530 /*
4531 * It's OK if we can't start a trans we can still check
4532 * from commit_root
4533 */
4534 if (IS_ERR(trans))
4535 trans = NULL;
4536
4537 /*
4538 * As btrfs supports shared space, this information
4539 * can be exported to userspace tools via
4540 * flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0
4541 * then we're just getting a count and we can skip the
4542 * lookup stuff.
4543 */
4544 ret = btrfs_check_shared(trans, root->fs_info,
4545 root->objectid,
4546 btrfs_ino(BTRFS_I(inode)), bytenr);
4547 if (trans)
4548 btrfs_end_transaction(trans);
4549 if (ret < 0)
4550 goto out_free;
4551 if (ret)
4552 flags |= FIEMAP_EXTENT_SHARED;
4553 ret = 0;
4554 }
4555 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4556 flags |= FIEMAP_EXTENT_ENCODED;
4557 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
4558 flags |= FIEMAP_EXTENT_UNWRITTEN;
4559
4560 free_extent_map(em);
4561 em = NULL;
4562 if ((em_start >= last) || em_len == (u64)-1 ||
4563 (last == (u64)-1 && isize <= em_end)) {
4564 flags |= FIEMAP_EXTENT_LAST;
4565 end = 1;
4566 }
4567
4568 /* now scan forward to see if this is really the last extent. */
4569 em = get_extent_skip_holes(inode, off, last_for_get_extent,
4570 get_extent);
4571 if (IS_ERR(em)) {
4572 ret = PTR_ERR(em);
4573 goto out;
4574 }
4575 if (!em) {
4576 flags |= FIEMAP_EXTENT_LAST;
4577 end = 1;
4578 }
4579 ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
4580 em_len, flags);
4581 if (ret) {
4582 if (ret == 1)
4583 ret = 0;
4584 goto out_free;
4585 }
4586 }
4587 out_free:
4588 free_extent_map(em);
4589 out:
4590 btrfs_free_path(path);
4591 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4592 &cached_state, GFP_NOFS);
4593 return ret;
4594 }
4595
4596 static void __free_extent_buffer(struct extent_buffer *eb)
4597 {
4598 btrfs_leak_debug_del(&eb->leak_list);
4599 kmem_cache_free(extent_buffer_cache, eb);
4600 }
4601
4602 int extent_buffer_under_io(struct extent_buffer *eb)
4603 {
4604 return (atomic_read(&eb->io_pages) ||
4605 test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
4606 test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4607 }
4608
4609 /*
4610 * Helper for releasing extent buffer page.
4611 */
4612 static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
4613 {
4614 unsigned long index;
4615 struct page *page;
4616 int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4617
4618 BUG_ON(extent_buffer_under_io(eb));
4619
4620 index = num_extent_pages(eb->start, eb->len);
4621 if (index == 0)
4622 return;
4623
4624 do {
4625 index--;
4626 page = eb->pages[index];
4627 if (!page)
4628 continue;
4629 if (mapped)
4630 spin_lock(&page->mapping->private_lock);
4631 /*
4632 * We do this since we'll remove the pages after we've
4633 * removed the eb from the radix tree, so we could race
4634 * and have this page now attached to the new eb. So
4635 * only clear page_private if it's still connected to
4636 * this eb.
4637 */
4638 if (PagePrivate(page) &&
4639 page->private == (unsigned long)eb) {
4640 BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4641 BUG_ON(PageDirty(page));
4642 BUG_ON(PageWriteback(page));
4643 /*
4644 * We need to make sure we haven't be attached
4645 * to a new eb.
4646 */
4647 ClearPagePrivate(page);
4648 set_page_private(page, 0);
4649 /* One for the page private */
4650 put_page(page);
4651 }
4652
4653 if (mapped)
4654 spin_unlock(&page->mapping->private_lock);
4655
4656 /* One for when we allocated the page */
4657 put_page(page);
4658 } while (index != 0);
4659 }
4660
4661 /*
4662 * Helper for releasing the extent buffer.
4663 */
4664 static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
4665 {
4666 btrfs_release_extent_buffer_page(eb);
4667 __free_extent_buffer(eb);
4668 }
4669
4670 static struct extent_buffer *
4671 __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
4672 unsigned long len)
4673 {
4674 struct extent_buffer *eb = NULL;
4675
4676 eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
4677 eb->start = start;
4678 eb->len = len;
4679 eb->fs_info = fs_info;
4680 eb->bflags = 0;
4681 rwlock_init(&eb->lock);
4682 atomic_set(&eb->write_locks, 0);
4683 atomic_set(&eb->read_locks, 0);
4684 atomic_set(&eb->blocking_readers, 0);
4685 atomic_set(&eb->blocking_writers, 0);
4686 atomic_set(&eb->spinning_readers, 0);
4687 atomic_set(&eb->spinning_writers, 0);
4688 eb->lock_nested = 0;
4689 init_waitqueue_head(&eb->write_lock_wq);
4690 init_waitqueue_head(&eb->read_lock_wq);
4691
4692 btrfs_leak_debug_add(&eb->leak_list, &buffers);
4693
4694 spin_lock_init(&eb->refs_lock);
4695 atomic_set(&eb->refs, 1);
4696 atomic_set(&eb->io_pages, 0);
4697
4698 /*
4699 * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
4700 */
4701 BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
4702 > MAX_INLINE_EXTENT_BUFFER_SIZE);
4703 BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
4704
4705 return eb;
4706 }
4707
4708 struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
4709 {
4710 unsigned long i;
4711 struct page *p;
4712 struct extent_buffer *new;
4713 unsigned long num_pages = num_extent_pages(src->start, src->len);
4714
4715 new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
4716 if (new == NULL)
4717 return NULL;
4718
4719 for (i = 0; i < num_pages; i++) {
4720 p = alloc_page(GFP_NOFS);
4721 if (!p) {
4722 btrfs_release_extent_buffer(new);
4723 return NULL;
4724 }
4725 attach_extent_buffer_page(new, p);
4726 WARN_ON(PageDirty(p));
4727 SetPageUptodate(p);
4728 new->pages[i] = p;
4729 copy_page(page_address(p), page_address(src->pages[i]));
4730 }
4731
4732 set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
4733 set_bit(EXTENT_BUFFER_DUMMY, &new->bflags);
4734
4735 return new;
4736 }
4737
4738 struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4739 u64 start, unsigned long len)
4740 {
4741 struct extent_buffer *eb;
4742 unsigned long num_pages;
4743 unsigned long i;
4744
4745 num_pages = num_extent_pages(start, len);
4746
4747 eb = __alloc_extent_buffer(fs_info, start, len);
4748 if (!eb)
4749 return NULL;
4750
4751 for (i = 0; i < num_pages; i++) {
4752 eb->pages[i] = alloc_page(GFP_NOFS);
4753 if (!eb->pages[i])
4754 goto err;
4755 }
4756 set_extent_buffer_uptodate(eb);
4757 btrfs_set_header_nritems(eb, 0);
4758 set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
4759
4760 return eb;
4761 err:
4762 for (; i > 0; i--)
4763 __free_page(eb->pages[i - 1]);
4764 __free_extent_buffer(eb);
4765 return NULL;
4766 }
4767
4768 struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4769 u64 start)
4770 {
4771 return __alloc_dummy_extent_buffer(fs_info, start, fs_info->nodesize);
4772 }
4773
4774 static void check_buffer_tree_ref(struct extent_buffer *eb)
4775 {
4776 int refs;
4777 /* the ref bit is tricky. We have to make sure it is set
4778 * if we have the buffer dirty. Otherwise the
4779 * code to free a buffer can end up dropping a dirty
4780 * page
4781 *
4782 * Once the ref bit is set, it won't go away while the
4783 * buffer is dirty or in writeback, and it also won't
4784 * go away while we have the reference count on the
4785 * eb bumped.
4786 *
4787 * We can't just set the ref bit without bumping the
4788 * ref on the eb because free_extent_buffer might
4789 * see the ref bit and try to clear it. If this happens
4790 * free_extent_buffer might end up dropping our original
4791 * ref by mistake and freeing the page before we are able
4792 * to add one more ref.
4793 *
4794 * So bump the ref count first, then set the bit. If someone
4795 * beat us to it, drop the ref we added.
4796 */
4797 refs = atomic_read(&eb->refs);
4798 if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4799 return;
4800
4801 spin_lock(&eb->refs_lock);
4802 if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4803 atomic_inc(&eb->refs);
4804 spin_unlock(&eb->refs_lock);
4805 }
4806
4807 static void mark_extent_buffer_accessed(struct extent_buffer *eb,
4808 struct page *accessed)
4809 {
4810 unsigned long num_pages, i;
4811
4812 check_buffer_tree_ref(eb);
4813
4814 num_pages = num_extent_pages(eb->start, eb->len);
4815 for (i = 0; i < num_pages; i++) {
4816 struct page *p = eb->pages[i];
4817
4818 if (p != accessed)
4819 mark_page_accessed(p);
4820 }
4821 }
4822
4823 struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
4824 u64 start)
4825 {
4826 struct extent_buffer *eb;
4827
4828 rcu_read_lock();
4829 eb = radix_tree_lookup(&fs_info->buffer_radix,
4830 start >> PAGE_SHIFT);
4831 if (eb && atomic_inc_not_zero(&eb->refs)) {
4832 rcu_read_unlock();
4833 /*
4834 * Lock our eb's refs_lock to avoid races with
4835 * free_extent_buffer. When we get our eb it might be flagged
4836 * with EXTENT_BUFFER_STALE and another task running
4837 * free_extent_buffer might have seen that flag set,
4838 * eb->refs == 2, that the buffer isn't under IO (dirty and
4839 * writeback flags not set) and it's still in the tree (flag
4840 * EXTENT_BUFFER_TREE_REF set), therefore being in the process
4841 * of decrementing the extent buffer's reference count twice.
4842 * So here we could race and increment the eb's reference count,
4843 * clear its stale flag, mark it as dirty and drop our reference
4844 * before the other task finishes executing free_extent_buffer,
4845 * which would later result in an attempt to free an extent
4846 * buffer that is dirty.
4847 */
4848 if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
4849 spin_lock(&eb->refs_lock);
4850 spin_unlock(&eb->refs_lock);
4851 }
4852 mark_extent_buffer_accessed(eb, NULL);
4853 return eb;
4854 }
4855 rcu_read_unlock();
4856
4857 return NULL;
4858 }
4859
4860 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4861 struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
4862 u64 start)
4863 {
4864 struct extent_buffer *eb, *exists = NULL;
4865 int ret;
4866
4867 eb = find_extent_buffer(fs_info, start);
4868 if (eb)
4869 return eb;
4870 eb = alloc_dummy_extent_buffer(fs_info, start);
4871 if (!eb)
4872 return NULL;
4873 eb->fs_info = fs_info;
4874 again:
4875 ret = radix_tree_preload(GFP_NOFS);
4876 if (ret)
4877 goto free_eb;
4878 spin_lock(&fs_info->buffer_lock);
4879 ret = radix_tree_insert(&fs_info->buffer_radix,
4880 start >> PAGE_SHIFT, eb);
4881 spin_unlock(&fs_info->buffer_lock);
4882 radix_tree_preload_end();
4883 if (ret == -EEXIST) {
4884 exists = find_extent_buffer(fs_info, start);
4885 if (exists)
4886 goto free_eb;
4887 else
4888 goto again;
4889 }
4890 check_buffer_tree_ref(eb);
4891 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
4892
4893 /*
4894 * We will free dummy extent buffer's if they come into
4895 * free_extent_buffer with a ref count of 2, but if we are using this we
4896 * want the buffers to stay in memory until we're done with them, so
4897 * bump the ref count again.
4898 */
4899 atomic_inc(&eb->refs);
4900 return eb;
4901 free_eb:
4902 btrfs_release_extent_buffer(eb);
4903 return exists;
4904 }
4905 #endif
4906
4907 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4908 u64 start)
4909 {
4910 unsigned long len = fs_info->nodesize;
4911 unsigned long num_pages = num_extent_pages(start, len);
4912 unsigned long i;
4913 unsigned long index = start >> PAGE_SHIFT;
4914 struct extent_buffer *eb;
4915 struct extent_buffer *exists = NULL;
4916 struct page *p;
4917 struct address_space *mapping = fs_info->btree_inode->i_mapping;
4918 int uptodate = 1;
4919 int ret;
4920
4921 if (!IS_ALIGNED(start, fs_info->sectorsize)) {
4922 btrfs_err(fs_info, "bad tree block start %llu", start);
4923 return ERR_PTR(-EINVAL);
4924 }
4925
4926 eb = find_extent_buffer(fs_info, start);
4927 if (eb)
4928 return eb;
4929
4930 eb = __alloc_extent_buffer(fs_info, start, len);
4931 if (!eb)
4932 return ERR_PTR(-ENOMEM);
4933
4934 for (i = 0; i < num_pages; i++, index++) {
4935 p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
4936 if (!p) {
4937 exists = ERR_PTR(-ENOMEM);
4938 goto free_eb;
4939 }
4940
4941 spin_lock(&mapping->private_lock);
4942 if (PagePrivate(p)) {
4943 /*
4944 * We could have already allocated an eb for this page
4945 * and attached one so lets see if we can get a ref on
4946 * the existing eb, and if we can we know it's good and
4947 * we can just return that one, else we know we can just
4948 * overwrite page->private.
4949 */
4950 exists = (struct extent_buffer *)p->private;
4951 if (atomic_inc_not_zero(&exists->refs)) {
4952 spin_unlock(&mapping->private_lock);
4953 unlock_page(p);
4954 put_page(p);
4955 mark_extent_buffer_accessed(exists, p);
4956 goto free_eb;
4957 }
4958 exists = NULL;
4959
4960 /*
4961 * Do this so attach doesn't complain and we need to
4962 * drop the ref the old guy had.
4963 */
4964 ClearPagePrivate(p);
4965 WARN_ON(PageDirty(p));
4966 put_page(p);
4967 }
4968 attach_extent_buffer_page(eb, p);
4969 spin_unlock(&mapping->private_lock);
4970 WARN_ON(PageDirty(p));
4971 eb->pages[i] = p;
4972 if (!PageUptodate(p))
4973 uptodate = 0;
4974
4975 /*
4976 * see below about how we avoid a nasty race with release page
4977 * and why we unlock later
4978 */
4979 }
4980 if (uptodate)
4981 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4982 again:
4983 ret = radix_tree_preload(GFP_NOFS);
4984 if (ret) {
4985 exists = ERR_PTR(ret);
4986 goto free_eb;
4987 }
4988
4989 spin_lock(&fs_info->buffer_lock);
4990 ret = radix_tree_insert(&fs_info->buffer_radix,
4991 start >> PAGE_SHIFT, eb);
4992 spin_unlock(&fs_info->buffer_lock);
4993 radix_tree_preload_end();
4994 if (ret == -EEXIST) {
4995 exists = find_extent_buffer(fs_info, start);
4996 if (exists)
4997 goto free_eb;
4998 else
4999 goto again;
5000 }
5001 /* add one reference for the tree */
5002 check_buffer_tree_ref(eb);
5003 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
5004
5005 /*
5006 * there is a race where release page may have
5007 * tried to find this extent buffer in the radix
5008 * but failed. It will tell the VM it is safe to
5009 * reclaim the, and it will clear the page private bit.
5010 * We must make sure to set the page private bit properly
5011 * after the extent buffer is in the radix tree so
5012 * it doesn't get lost
5013 */
5014 SetPageChecked(eb->pages[0]);
5015 for (i = 1; i < num_pages; i++) {
5016 p = eb->pages[i];
5017 ClearPageChecked(p);
5018 unlock_page(p);
5019 }
5020 unlock_page(eb->pages[0]);
5021 return eb;
5022
5023 free_eb:
5024 WARN_ON(!atomic_dec_and_test(&eb->refs));
5025 for (i = 0; i < num_pages; i++) {
5026 if (eb->pages[i])
5027 unlock_page(eb->pages[i]);
5028 }
5029
5030 btrfs_release_extent_buffer(eb);
5031 return exists;
5032 }
5033
5034 static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
5035 {
5036 struct extent_buffer *eb =
5037 container_of(head, struct extent_buffer, rcu_head);
5038
5039 __free_extent_buffer(eb);
5040 }
5041
5042 /* Expects to have eb->eb_lock already held */
5043 static int release_extent_buffer(struct extent_buffer *eb)
5044 {
5045 WARN_ON(atomic_read(&eb->refs) == 0);
5046 if (atomic_dec_and_test(&eb->refs)) {
5047 if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
5048 struct btrfs_fs_info *fs_info = eb->fs_info;
5049
5050 spin_unlock(&eb->refs_lock);
5051
5052 spin_lock(&fs_info->buffer_lock);
5053 radix_tree_delete(&fs_info->buffer_radix,
5054 eb->start >> PAGE_SHIFT);
5055 spin_unlock(&fs_info->buffer_lock);
5056 } else {
5057 spin_unlock(&eb->refs_lock);
5058 }
5059
5060 /* Should be safe to release our pages at this point */
5061 btrfs_release_extent_buffer_page(eb);
5062 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5063 if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))) {
5064 __free_extent_buffer(eb);
5065 return 1;
5066 }
5067 #endif
5068 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
5069 return 1;
5070 }
5071 spin_unlock(&eb->refs_lock);
5072
5073 return 0;
5074 }
5075
5076 void free_extent_buffer(struct extent_buffer *eb)
5077 {
5078 int refs;
5079 int old;
5080 if (!eb)
5081 return;
5082
5083 while (1) {
5084 refs = atomic_read(&eb->refs);
5085 if (refs <= 3)
5086 break;
5087 old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
5088 if (old == refs)
5089 return;
5090 }
5091
5092 spin_lock(&eb->refs_lock);
5093 if (atomic_read(&eb->refs) == 2 &&
5094 test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
5095 atomic_dec(&eb->refs);
5096
5097 if (atomic_read(&eb->refs) == 2 &&
5098 test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
5099 !extent_buffer_under_io(eb) &&
5100 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5101 atomic_dec(&eb->refs);
5102
5103 /*
5104 * I know this is terrible, but it's temporary until we stop tracking
5105 * the uptodate bits and such for the extent buffers.
5106 */
5107 release_extent_buffer(eb);
5108 }
5109
5110 void free_extent_buffer_stale(struct extent_buffer *eb)
5111 {
5112 if (!eb)
5113 return;
5114
5115 spin_lock(&eb->refs_lock);
5116 set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
5117
5118 if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
5119 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5120 atomic_dec(&eb->refs);
5121 release_extent_buffer(eb);
5122 }
5123
5124 void clear_extent_buffer_dirty(struct extent_buffer *eb)
5125 {
5126 unsigned long i;
5127 unsigned long num_pages;
5128 struct page *page;
5129
5130 num_pages = num_extent_pages(eb->start, eb->len);
5131
5132 for (i = 0; i < num_pages; i++) {
5133 page = eb->pages[i];
5134 if (!PageDirty(page))
5135 continue;
5136
5137 lock_page(page);
5138 WARN_ON(!PagePrivate(page));
5139
5140 clear_page_dirty_for_io(page);
5141 spin_lock_irq(&page->mapping->tree_lock);
5142 if (!PageDirty(page)) {
5143 radix_tree_tag_clear(&page->mapping->page_tree,
5144 page_index(page),
5145 PAGECACHE_TAG_DIRTY);
5146 }
5147 spin_unlock_irq(&page->mapping->tree_lock);
5148 ClearPageError(page);
5149 unlock_page(page);
5150 }
5151 WARN_ON(atomic_read(&eb->refs) == 0);
5152 }
5153
5154 int set_extent_buffer_dirty(struct extent_buffer *eb)
5155 {
5156 unsigned long i;
5157 unsigned long num_pages;
5158 int was_dirty = 0;
5159
5160 check_buffer_tree_ref(eb);
5161
5162 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
5163
5164 num_pages = num_extent_pages(eb->start, eb->len);
5165 WARN_ON(atomic_read(&eb->refs) == 0);
5166 WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
5167
5168 for (i = 0; i < num_pages; i++)
5169 set_page_dirty(eb->pages[i]);
5170 return was_dirty;
5171 }
5172
5173 void clear_extent_buffer_uptodate(struct extent_buffer *eb)
5174 {
5175 unsigned long i;
5176 struct page *page;
5177 unsigned long num_pages;
5178
5179 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5180 num_pages = num_extent_pages(eb->start, eb->len);
5181 for (i = 0; i < num_pages; i++) {
5182 page = eb->pages[i];
5183 if (page)
5184 ClearPageUptodate(page);
5185 }
5186 }
5187
5188 void set_extent_buffer_uptodate(struct extent_buffer *eb)
5189 {
5190 unsigned long i;
5191 struct page *page;
5192 unsigned long num_pages;
5193
5194 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5195 num_pages = num_extent_pages(eb->start, eb->len);
5196 for (i = 0; i < num_pages; i++) {
5197 page = eb->pages[i];
5198 SetPageUptodate(page);
5199 }
5200 }
5201
5202 int extent_buffer_uptodate(struct extent_buffer *eb)
5203 {
5204 return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5205 }
5206
5207 int read_extent_buffer_pages(struct extent_io_tree *tree,
5208 struct extent_buffer *eb, int wait,
5209 get_extent_t *get_extent, int mirror_num)
5210 {
5211 unsigned long i;
5212 struct page *page;
5213 int err;
5214 int ret = 0;
5215 int locked_pages = 0;
5216 int all_uptodate = 1;
5217 unsigned long num_pages;
5218 unsigned long num_reads = 0;
5219 struct bio *bio = NULL;
5220 unsigned long bio_flags = 0;
5221
5222 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
5223 return 0;
5224
5225 num_pages = num_extent_pages(eb->start, eb->len);
5226 for (i = 0; i < num_pages; i++) {
5227 page = eb->pages[i];
5228 if (wait == WAIT_NONE) {
5229 if (!trylock_page(page))
5230 goto unlock_exit;
5231 } else {
5232 lock_page(page);
5233 }
5234 locked_pages++;
5235 }
5236 /*
5237 * We need to firstly lock all pages to make sure that
5238 * the uptodate bit of our pages won't be affected by
5239 * clear_extent_buffer_uptodate().
5240 */
5241 for (i = 0; i < num_pages; i++) {
5242 page = eb->pages[i];
5243 if (!PageUptodate(page)) {
5244 num_reads++;
5245 all_uptodate = 0;
5246 }
5247 }
5248
5249 if (all_uptodate) {
5250 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5251 goto unlock_exit;
5252 }
5253
5254 clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
5255 eb->read_mirror = 0;
5256 atomic_set(&eb->io_pages, num_reads);
5257 for (i = 0; i < num_pages; i++) {
5258 page = eb->pages[i];
5259
5260 if (!PageUptodate(page)) {
5261 if (ret) {
5262 atomic_dec(&eb->io_pages);
5263 unlock_page(page);
5264 continue;
5265 }
5266
5267 ClearPageError(page);
5268 err = __extent_read_full_page(tree, page,
5269 get_extent, &bio,
5270 mirror_num, &bio_flags,
5271 REQ_META);
5272 if (err) {
5273 ret = err;
5274 /*
5275 * We use &bio in above __extent_read_full_page,
5276 * so we ensure that if it returns error, the
5277 * current page fails to add itself to bio and
5278 * it's been unlocked.
5279 *
5280 * We must dec io_pages by ourselves.
5281 */
5282 atomic_dec(&eb->io_pages);
5283 }
5284 } else {
5285 unlock_page(page);
5286 }
5287 }
5288
5289 if (bio) {
5290 err = submit_one_bio(bio, mirror_num, bio_flags);
5291 if (err)
5292 return err;
5293 }
5294
5295 if (ret || wait != WAIT_COMPLETE)
5296 return ret;
5297
5298 for (i = 0; i < num_pages; i++) {
5299 page = eb->pages[i];
5300 wait_on_page_locked(page);
5301 if (!PageUptodate(page))
5302 ret = -EIO;
5303 }
5304
5305 return ret;
5306
5307 unlock_exit:
5308 while (locked_pages > 0) {
5309 locked_pages--;
5310 page = eb->pages[locked_pages];
5311 unlock_page(page);
5312 }
5313 return ret;
5314 }
5315
5316 void read_extent_buffer(struct extent_buffer *eb, void *dstv,
5317 unsigned long start,
5318 unsigned long len)
5319 {
5320 size_t cur;
5321 size_t offset;
5322 struct page *page;
5323 char *kaddr;
5324 char *dst = (char *)dstv;
5325 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5326 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5327
5328 WARN_ON(start > eb->len);
5329 WARN_ON(start + len > eb->start + eb->len);
5330
5331 offset = (start_offset + start) & (PAGE_SIZE - 1);
5332
5333 while (len > 0) {
5334 page = eb->pages[i];
5335
5336 cur = min(len, (PAGE_SIZE - offset));
5337 kaddr = page_address(page);
5338 memcpy(dst, kaddr + offset, cur);
5339
5340 dst += cur;
5341 len -= cur;
5342 offset = 0;
5343 i++;
5344 }
5345 }
5346
5347 int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
5348 unsigned long start,
5349 unsigned long len)
5350 {
5351 size_t cur;
5352 size_t offset;
5353 struct page *page;
5354 char *kaddr;
5355 char __user *dst = (char __user *)dstv;
5356 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5357 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5358 int ret = 0;
5359
5360 WARN_ON(start > eb->len);
5361 WARN_ON(start + len > eb->start + eb->len);
5362
5363 offset = (start_offset + start) & (PAGE_SIZE - 1);
5364
5365 while (len > 0) {
5366 page = eb->pages[i];
5367
5368 cur = min(len, (PAGE_SIZE - offset));
5369 kaddr = page_address(page);
5370 if (copy_to_user(dst, kaddr + offset, cur)) {
5371 ret = -EFAULT;
5372 break;
5373 }
5374
5375 dst += cur;
5376 len -= cur;
5377 offset = 0;
5378 i++;
5379 }
5380
5381 return ret;
5382 }
5383
5384 /*
5385 * return 0 if the item is found within a page.
5386 * return 1 if the item spans two pages.
5387 * return -EINVAL otherwise.
5388 */
5389 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
5390 unsigned long min_len, char **map,
5391 unsigned long *map_start,
5392 unsigned long *map_len)
5393 {
5394 size_t offset = start & (PAGE_SIZE - 1);
5395 char *kaddr;
5396 struct page *p;
5397 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5398 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5399 unsigned long end_i = (start_offset + start + min_len - 1) >>
5400 PAGE_SHIFT;
5401
5402 if (i != end_i)
5403 return 1;
5404
5405 if (i == 0) {
5406 offset = start_offset;
5407 *map_start = 0;
5408 } else {
5409 offset = 0;
5410 *map_start = ((u64)i << PAGE_SHIFT) - start_offset;
5411 }
5412
5413 if (start + min_len > eb->len) {
5414 WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
5415 eb->start, eb->len, start, min_len);
5416 return -EINVAL;
5417 }
5418
5419 p = eb->pages[i];
5420 kaddr = page_address(p);
5421 *map = kaddr + offset;
5422 *map_len = PAGE_SIZE - offset;
5423 return 0;
5424 }
5425
5426 int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
5427 unsigned long start,
5428 unsigned long len)
5429 {
5430 size_t cur;
5431 size_t offset;
5432 struct page *page;
5433 char *kaddr;
5434 char *ptr = (char *)ptrv;
5435 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5436 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5437 int ret = 0;
5438
5439 WARN_ON(start > eb->len);
5440 WARN_ON(start + len > eb->start + eb->len);
5441
5442 offset = (start_offset + start) & (PAGE_SIZE - 1);
5443
5444 while (len > 0) {
5445 page = eb->pages[i];
5446
5447 cur = min(len, (PAGE_SIZE - offset));
5448
5449 kaddr = page_address(page);
5450 ret = memcmp(ptr, kaddr + offset, cur);
5451 if (ret)
5452 break;
5453
5454 ptr += cur;
5455 len -= cur;
5456 offset = 0;
5457 i++;
5458 }
5459 return ret;
5460 }
5461
5462 void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
5463 const void *srcv)
5464 {
5465 char *kaddr;
5466
5467 WARN_ON(!PageUptodate(eb->pages[0]));
5468 kaddr = page_address(eb->pages[0]);
5469 memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,
5470 BTRFS_FSID_SIZE);
5471 }
5472
5473 void write_extent_buffer_fsid(struct extent_buffer *eb, const void *srcv)
5474 {
5475 char *kaddr;
5476
5477 WARN_ON(!PageUptodate(eb->pages[0]));
5478 kaddr = page_address(eb->pages[0]);
5479 memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,
5480 BTRFS_FSID_SIZE);
5481 }
5482
5483 void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
5484 unsigned long start, unsigned long len)
5485 {
5486 size_t cur;
5487 size_t offset;
5488 struct page *page;
5489 char *kaddr;
5490 char *src = (char *)srcv;
5491 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5492 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5493
5494 WARN_ON(start > eb->len);
5495 WARN_ON(start + len > eb->start + eb->len);
5496
5497 offset = (start_offset + start) & (PAGE_SIZE - 1);
5498
5499 while (len > 0) {
5500 page = eb->pages[i];
5501 WARN_ON(!PageUptodate(page));
5502
5503 cur = min(len, PAGE_SIZE - offset);
5504 kaddr = page_address(page);
5505 memcpy(kaddr + offset, src, cur);
5506
5507 src += cur;
5508 len -= cur;
5509 offset = 0;
5510 i++;
5511 }
5512 }
5513
5514 void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
5515 unsigned long len)
5516 {
5517 size_t cur;
5518 size_t offset;
5519 struct page *page;
5520 char *kaddr;
5521 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5522 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5523
5524 WARN_ON(start > eb->len);
5525 WARN_ON(start + len > eb->start + eb->len);
5526
5527 offset = (start_offset + start) & (PAGE_SIZE - 1);
5528
5529 while (len > 0) {
5530 page = eb->pages[i];
5531 WARN_ON(!PageUptodate(page));
5532
5533 cur = min(len, PAGE_SIZE - offset);
5534 kaddr = page_address(page);
5535 memset(kaddr + offset, 0, cur);
5536
5537 len -= cur;
5538 offset = 0;
5539 i++;
5540 }
5541 }
5542
5543 void copy_extent_buffer_full(struct extent_buffer *dst,
5544 struct extent_buffer *src)
5545 {
5546 int i;
5547 unsigned num_pages;
5548
5549 ASSERT(dst->len == src->len);
5550
5551 num_pages = num_extent_pages(dst->start, dst->len);
5552 for (i = 0; i < num_pages; i++)
5553 copy_page(page_address(dst->pages[i]),
5554 page_address(src->pages[i]));
5555 }
5556
5557 void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
5558 unsigned long dst_offset, unsigned long src_offset,
5559 unsigned long len)
5560 {
5561 u64 dst_len = dst->len;
5562 size_t cur;
5563 size_t offset;
5564 struct page *page;
5565 char *kaddr;
5566 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5567 unsigned long i = (start_offset + dst_offset) >> PAGE_SHIFT;
5568
5569 WARN_ON(src->len != dst_len);
5570
5571 offset = (start_offset + dst_offset) &
5572 (PAGE_SIZE - 1);
5573
5574 while (len > 0) {
5575 page = dst->pages[i];
5576 WARN_ON(!PageUptodate(page));
5577
5578 cur = min(len, (unsigned long)(PAGE_SIZE - offset));
5579
5580 kaddr = page_address(page);
5581 read_extent_buffer(src, kaddr + offset, src_offset, cur);
5582
5583 src_offset += cur;
5584 len -= cur;
5585 offset = 0;
5586 i++;
5587 }
5588 }
5589
5590 void le_bitmap_set(u8 *map, unsigned int start, int len)
5591 {
5592 u8 *p = map + BIT_BYTE(start);
5593 const unsigned int size = start + len;
5594 int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
5595 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
5596
5597 while (len - bits_to_set >= 0) {
5598 *p |= mask_to_set;
5599 len -= bits_to_set;
5600 bits_to_set = BITS_PER_BYTE;
5601 mask_to_set = ~0;
5602 p++;
5603 }
5604 if (len) {
5605 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5606 *p |= mask_to_set;
5607 }
5608 }
5609
5610 void le_bitmap_clear(u8 *map, unsigned int start, int len)
5611 {
5612 u8 *p = map + BIT_BYTE(start);
5613 const unsigned int size = start + len;
5614 int bits_to_clear = BITS_PER_BYTE - (start % BITS_PER_BYTE);
5615 u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(start);
5616
5617 while (len - bits_to_clear >= 0) {
5618 *p &= ~mask_to_clear;
5619 len -= bits_to_clear;
5620 bits_to_clear = BITS_PER_BYTE;
5621 mask_to_clear = ~0;
5622 p++;
5623 }
5624 if (len) {
5625 mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5626 *p &= ~mask_to_clear;
5627 }
5628 }
5629
5630 /*
5631 * eb_bitmap_offset() - calculate the page and offset of the byte containing the
5632 * given bit number
5633 * @eb: the extent buffer
5634 * @start: offset of the bitmap item in the extent buffer
5635 * @nr: bit number
5636 * @page_index: return index of the page in the extent buffer that contains the
5637 * given bit number
5638 * @page_offset: return offset into the page given by page_index
5639 *
5640 * This helper hides the ugliness of finding the byte in an extent buffer which
5641 * contains a given bit.
5642 */
5643 static inline void eb_bitmap_offset(struct extent_buffer *eb,
5644 unsigned long start, unsigned long nr,
5645 unsigned long *page_index,
5646 size_t *page_offset)
5647 {
5648 size_t start_offset = eb->start & ((u64)PAGE_SIZE - 1);
5649 size_t byte_offset = BIT_BYTE(nr);
5650 size_t offset;
5651
5652 /*
5653 * The byte we want is the offset of the extent buffer + the offset of
5654 * the bitmap item in the extent buffer + the offset of the byte in the
5655 * bitmap item.
5656 */
5657 offset = start_offset + start + byte_offset;
5658
5659 *page_index = offset >> PAGE_SHIFT;
5660 *page_offset = offset & (PAGE_SIZE - 1);
5661 }
5662
5663 /**
5664 * extent_buffer_test_bit - determine whether a bit in a bitmap item is set
5665 * @eb: the extent buffer
5666 * @start: offset of the bitmap item in the extent buffer
5667 * @nr: bit number to test
5668 */
5669 int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
5670 unsigned long nr)
5671 {
5672 u8 *kaddr;
5673 struct page *page;
5674 unsigned long i;
5675 size_t offset;
5676
5677 eb_bitmap_offset(eb, start, nr, &i, &offset);
5678 page = eb->pages[i];
5679 WARN_ON(!PageUptodate(page));
5680 kaddr = page_address(page);
5681 return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
5682 }
5683
5684 /**
5685 * extent_buffer_bitmap_set - set an area of a bitmap
5686 * @eb: the extent buffer
5687 * @start: offset of the bitmap item in the extent buffer
5688 * @pos: bit number of the first bit
5689 * @len: number of bits to set
5690 */
5691 void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
5692 unsigned long pos, unsigned long len)
5693 {
5694 u8 *kaddr;
5695 struct page *page;
5696 unsigned long i;
5697 size_t offset;
5698 const unsigned int size = pos + len;
5699 int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5700 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
5701
5702 eb_bitmap_offset(eb, start, pos, &i, &offset);
5703 page = eb->pages[i];
5704 WARN_ON(!PageUptodate(page));
5705 kaddr = page_address(page);
5706
5707 while (len >= bits_to_set) {
5708 kaddr[offset] |= mask_to_set;
5709 len -= bits_to_set;
5710 bits_to_set = BITS_PER_BYTE;
5711 mask_to_set = ~0;
5712 if (++offset >= PAGE_SIZE && len > 0) {
5713 offset = 0;
5714 page = eb->pages[++i];
5715 WARN_ON(!PageUptodate(page));
5716 kaddr = page_address(page);
5717 }
5718 }
5719 if (len) {
5720 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5721 kaddr[offset] |= mask_to_set;
5722 }
5723 }
5724
5725
5726 /**
5727 * extent_buffer_bitmap_clear - clear an area of a bitmap
5728 * @eb: the extent buffer
5729 * @start: offset of the bitmap item in the extent buffer
5730 * @pos: bit number of the first bit
5731 * @len: number of bits to clear
5732 */
5733 void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
5734 unsigned long pos, unsigned long len)
5735 {
5736 u8 *kaddr;
5737 struct page *page;
5738 unsigned long i;
5739 size_t offset;
5740 const unsigned int size = pos + len;
5741 int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5742 u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
5743
5744 eb_bitmap_offset(eb, start, pos, &i, &offset);
5745 page = eb->pages[i];
5746 WARN_ON(!PageUptodate(page));
5747 kaddr = page_address(page);
5748
5749 while (len >= bits_to_clear) {
5750 kaddr[offset] &= ~mask_to_clear;
5751 len -= bits_to_clear;
5752 bits_to_clear = BITS_PER_BYTE;
5753 mask_to_clear = ~0;
5754 if (++offset >= PAGE_SIZE && len > 0) {
5755 offset = 0;
5756 page = eb->pages[++i];
5757 WARN_ON(!PageUptodate(page));
5758 kaddr = page_address(page);
5759 }
5760 }
5761 if (len) {
5762 mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5763 kaddr[offset] &= ~mask_to_clear;
5764 }
5765 }
5766
5767 static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
5768 {
5769 unsigned long distance = (src > dst) ? src - dst : dst - src;
5770 return distance < len;
5771 }
5772
5773 static void copy_pages(struct page *dst_page, struct page *src_page,
5774 unsigned long dst_off, unsigned long src_off,
5775 unsigned long len)
5776 {
5777 char *dst_kaddr = page_address(dst_page);
5778 char *src_kaddr;
5779 int must_memmove = 0;
5780
5781 if (dst_page != src_page) {
5782 src_kaddr = page_address(src_page);
5783 } else {
5784 src_kaddr = dst_kaddr;
5785 if (areas_overlap(src_off, dst_off, len))
5786 must_memmove = 1;
5787 }
5788
5789 if (must_memmove)
5790 memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
5791 else
5792 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5793 }
5794
5795 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5796 unsigned long src_offset, unsigned long len)
5797 {
5798 struct btrfs_fs_info *fs_info = dst->fs_info;
5799 size_t cur;
5800 size_t dst_off_in_page;
5801 size_t src_off_in_page;
5802 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5803 unsigned long dst_i;
5804 unsigned long src_i;
5805
5806 if (src_offset + len > dst->len) {
5807 btrfs_err(fs_info,
5808 "memmove bogus src_offset %lu move len %lu dst len %lu",
5809 src_offset, len, dst->len);
5810 BUG_ON(1);
5811 }
5812 if (dst_offset + len > dst->len) {
5813 btrfs_err(fs_info,
5814 "memmove bogus dst_offset %lu move len %lu dst len %lu",
5815 dst_offset, len, dst->len);
5816 BUG_ON(1);
5817 }
5818
5819 while (len > 0) {
5820 dst_off_in_page = (start_offset + dst_offset) &
5821 (PAGE_SIZE - 1);
5822 src_off_in_page = (start_offset + src_offset) &
5823 (PAGE_SIZE - 1);
5824
5825 dst_i = (start_offset + dst_offset) >> PAGE_SHIFT;
5826 src_i = (start_offset + src_offset) >> PAGE_SHIFT;
5827
5828 cur = min(len, (unsigned long)(PAGE_SIZE -
5829 src_off_in_page));
5830 cur = min_t(unsigned long, cur,
5831 (unsigned long)(PAGE_SIZE - dst_off_in_page));
5832
5833 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5834 dst_off_in_page, src_off_in_page, cur);
5835
5836 src_offset += cur;
5837 dst_offset += cur;
5838 len -= cur;
5839 }
5840 }
5841
5842 void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5843 unsigned long src_offset, unsigned long len)
5844 {
5845 struct btrfs_fs_info *fs_info = dst->fs_info;
5846 size_t cur;
5847 size_t dst_off_in_page;
5848 size_t src_off_in_page;
5849 unsigned long dst_end = dst_offset + len - 1;
5850 unsigned long src_end = src_offset + len - 1;
5851 size_t start_offset = dst->start & ((u64)PAGE_SIZE - 1);
5852 unsigned long dst_i;
5853 unsigned long src_i;
5854
5855 if (src_offset + len > dst->len) {
5856 btrfs_err(fs_info,
5857 "memmove bogus src_offset %lu move len %lu len %lu",
5858 src_offset, len, dst->len);
5859 BUG_ON(1);
5860 }
5861 if (dst_offset + len > dst->len) {
5862 btrfs_err(fs_info,
5863 "memmove bogus dst_offset %lu move len %lu len %lu",
5864 dst_offset, len, dst->len);
5865 BUG_ON(1);
5866 }
5867 if (dst_offset < src_offset) {
5868 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
5869 return;
5870 }
5871 while (len > 0) {
5872 dst_i = (start_offset + dst_end) >> PAGE_SHIFT;
5873 src_i = (start_offset + src_end) >> PAGE_SHIFT;
5874
5875 dst_off_in_page = (start_offset + dst_end) &
5876 (PAGE_SIZE - 1);
5877 src_off_in_page = (start_offset + src_end) &
5878 (PAGE_SIZE - 1);
5879
5880 cur = min_t(unsigned long, len, src_off_in_page + 1);
5881 cur = min(cur, dst_off_in_page + 1);
5882 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5883 dst_off_in_page - cur + 1,
5884 src_off_in_page - cur + 1, cur);
5885
5886 dst_end -= cur;
5887 src_end -= cur;
5888 len -= cur;
5889 }
5890 }
5891
5892 int try_release_extent_buffer(struct page *page)
5893 {
5894 struct extent_buffer *eb;
5895
5896 /*
5897 * We need to make sure nobody is attaching this page to an eb right
5898 * now.
5899 */
5900 spin_lock(&page->mapping->private_lock);
5901 if (!PagePrivate(page)) {
5902 spin_unlock(&page->mapping->private_lock);
5903 return 1;
5904 }
5905
5906 eb = (struct extent_buffer *)page->private;
5907 BUG_ON(!eb);
5908
5909 /*
5910 * This is a little awful but should be ok, we need to make sure that
5911 * the eb doesn't disappear out from under us while we're looking at
5912 * this page.
5913 */
5914 spin_lock(&eb->refs_lock);
5915 if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5916 spin_unlock(&eb->refs_lock);
5917 spin_unlock(&page->mapping->private_lock);
5918 return 0;
5919 }
5920 spin_unlock(&page->mapping->private_lock);
5921
5922 /*
5923 * If tree ref isn't set then we know the ref on this eb is a real ref,
5924 * so just return, this page will likely be freed soon anyway.
5925 */
5926 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
5927 spin_unlock(&eb->refs_lock);
5928 return 0;
5929 }
5930
5931 return release_extent_buffer(eb);
5932 }