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1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/bitops.h>
4#include <linux/slab.h>
5#include <linux/bio.h>
6#include <linux/mm.h>
7#include <linux/pagemap.h>
8#include <linux/page-flags.h>
9#include <linux/spinlock.h>
10#include <linux/blkdev.h>
11#include <linux/swap.h>
12#include <linux/writeback.h>
13#include <linux/pagevec.h>
14#include <linux/prefetch.h>
15#include <linux/cleancache.h>
16#include "extent_io.h"
17#include "extent_map.h"
18#include "ctree.h"
19#include "btrfs_inode.h"
20#include "volumes.h"
21#include "check-integrity.h"
22#include "locking.h"
23#include "rcu-string.h"
24#include "backref.h"
25#include "disk-io.h"
26
27static struct kmem_cache *extent_state_cache;
28static struct kmem_cache *extent_buffer_cache;
29static struct bio_set btrfs_bioset;
30
31static inline bool extent_state_in_tree(const struct extent_state *state)
32{
33 return !RB_EMPTY_NODE(&state->rb_node);
34}
35
36#ifdef CONFIG_BTRFS_DEBUG
37static LIST_HEAD(buffers);
38static LIST_HEAD(states);
39
40static DEFINE_SPINLOCK(leak_lock);
41
42static inline
43void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
44{
45 unsigned long flags;
46
47 spin_lock_irqsave(&leak_lock, flags);
48 list_add(new, head);
49 spin_unlock_irqrestore(&leak_lock, flags);
50}
51
52static inline
53void btrfs_leak_debug_del(struct list_head *entry)
54{
55 unsigned long flags;
56
57 spin_lock_irqsave(&leak_lock, flags);
58 list_del(entry);
59 spin_unlock_irqrestore(&leak_lock, flags);
60}
61
62static inline
63void btrfs_leak_debug_check(void)
64{
65 struct extent_state *state;
66 struct extent_buffer *eb;
67
68 while (!list_empty(&states)) {
69 state = list_entry(states.next, struct extent_state, leak_list);
70 pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
71 state->start, state->end, state->state,
72 extent_state_in_tree(state),
73 refcount_read(&state->refs));
74 list_del(&state->leak_list);
75 kmem_cache_free(extent_state_cache, state);
76 }
77
78 while (!list_empty(&buffers)) {
79 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
80 pr_err("BTRFS: buffer leak start %llu len %lu refs %d bflags %lu\n",
81 eb->start, eb->len, atomic_read(&eb->refs), eb->bflags);
82 list_del(&eb->leak_list);
83 kmem_cache_free(extent_buffer_cache, eb);
84 }
85}
86
87#define btrfs_debug_check_extent_io_range(tree, start, end) \
88 __btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
89static inline void __btrfs_debug_check_extent_io_range(const char *caller,
90 struct extent_io_tree *tree, u64 start, u64 end)
91{
92 struct inode *inode = tree->private_data;
93 u64 isize;
94
95 if (!inode || !is_data_inode(inode))
96 return;
97
98 isize = i_size_read(inode);
99 if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
100 btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
101 "%s: ino %llu isize %llu odd range [%llu,%llu]",
102 caller, btrfs_ino(BTRFS_I(inode)), isize, start, end);
103 }
104}
105#else
106#define btrfs_leak_debug_add(new, head) do {} while (0)
107#define btrfs_leak_debug_del(entry) do {} while (0)
108#define btrfs_leak_debug_check() do {} while (0)
109#define btrfs_debug_check_extent_io_range(c, s, e) do {} while (0)
110#endif
111
112struct tree_entry {
113 u64 start;
114 u64 end;
115 struct rb_node rb_node;
116};
117
118struct extent_page_data {
119 struct bio *bio;
120 struct extent_io_tree *tree;
121 /* tells writepage not to lock the state bits for this range
122 * it still does the unlocking
123 */
124 unsigned int extent_locked:1;
125
126 /* tells the submit_bio code to use REQ_SYNC */
127 unsigned int sync_io:1;
128};
129
130static int add_extent_changeset(struct extent_state *state, unsigned bits,
131 struct extent_changeset *changeset,
132 int set)
133{
134 int ret;
135
136 if (!changeset)
137 return 0;
138 if (set && (state->state & bits) == bits)
139 return 0;
140 if (!set && (state->state & bits) == 0)
141 return 0;
142 changeset->bytes_changed += state->end - state->start + 1;
143 ret = ulist_add(&changeset->range_changed, state->start, state->end,
144 GFP_ATOMIC);
145 return ret;
146}
147
148static int __must_check submit_one_bio(struct bio *bio, int mirror_num,
149 unsigned long bio_flags)
150{
151 blk_status_t ret = 0;
152 struct extent_io_tree *tree = bio->bi_private;
153
154 bio->bi_private = NULL;
155
156 if (tree->ops)
157 ret = tree->ops->submit_bio_hook(tree->private_data, bio,
158 mirror_num, bio_flags);
159 else
160 btrfsic_submit_bio(bio);
161
162 return blk_status_to_errno(ret);
163}
164
165/* Cleanup unsubmitted bios */
166static void end_write_bio(struct extent_page_data *epd, int ret)
167{
168 if (epd->bio) {
169 epd->bio->bi_status = errno_to_blk_status(ret);
170 bio_endio(epd->bio);
171 epd->bio = NULL;
172 }
173}
174
175/*
176 * Submit bio from extent page data via submit_one_bio
177 *
178 * Return 0 if everything is OK.
179 * Return <0 for error.
180 */
181static int __must_check flush_write_bio(struct extent_page_data *epd)
182{
183 int ret = 0;
184
185 if (epd->bio) {
186 ret = submit_one_bio(epd->bio, 0, 0);
187 /*
188 * Clean up of epd->bio is handled by its endio function.
189 * And endio is either triggered by successful bio execution
190 * or the error handler of submit bio hook.
191 * So at this point, no matter what happened, we don't need
192 * to clean up epd->bio.
193 */
194 epd->bio = NULL;
195 }
196 return ret;
197}
198
199int __init extent_io_init(void)
200{
201 extent_state_cache = kmem_cache_create("btrfs_extent_state",
202 sizeof(struct extent_state), 0,
203 SLAB_MEM_SPREAD, NULL);
204 if (!extent_state_cache)
205 return -ENOMEM;
206
207 extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
208 sizeof(struct extent_buffer), 0,
209 SLAB_MEM_SPREAD, NULL);
210 if (!extent_buffer_cache)
211 goto free_state_cache;
212
213 if (bioset_init(&btrfs_bioset, BIO_POOL_SIZE,
214 offsetof(struct btrfs_io_bio, bio),
215 BIOSET_NEED_BVECS))
216 goto free_buffer_cache;
217
218 if (bioset_integrity_create(&btrfs_bioset, BIO_POOL_SIZE))
219 goto free_bioset;
220
221 return 0;
222
223free_bioset:
224 bioset_exit(&btrfs_bioset);
225
226free_buffer_cache:
227 kmem_cache_destroy(extent_buffer_cache);
228 extent_buffer_cache = NULL;
229
230free_state_cache:
231 kmem_cache_destroy(extent_state_cache);
232 extent_state_cache = NULL;
233 return -ENOMEM;
234}
235
236void __cold extent_io_exit(void)
237{
238 btrfs_leak_debug_check();
239
240 /*
241 * Make sure all delayed rcu free are flushed before we
242 * destroy caches.
243 */
244 rcu_barrier();
245 kmem_cache_destroy(extent_state_cache);
246 kmem_cache_destroy(extent_buffer_cache);
247 bioset_exit(&btrfs_bioset);
248}
249
250void extent_io_tree_init(struct btrfs_fs_info *fs_info,
251 struct extent_io_tree *tree, unsigned int owner,
252 void *private_data)
253{
254 tree->fs_info = fs_info;
255 tree->state = RB_ROOT;
256 tree->ops = NULL;
257 tree->dirty_bytes = 0;
258 spin_lock_init(&tree->lock);
259 tree->private_data = private_data;
260 tree->owner = owner;
261}
262
263void extent_io_tree_release(struct extent_io_tree *tree)
264{
265 spin_lock(&tree->lock);
266 /*
267 * Do a single barrier for the waitqueue_active check here, the state
268 * of the waitqueue should not change once extent_io_tree_release is
269 * called.
270 */
271 smp_mb();
272 while (!RB_EMPTY_ROOT(&tree->state)) {
273 struct rb_node *node;
274 struct extent_state *state;
275
276 node = rb_first(&tree->state);
277 state = rb_entry(node, struct extent_state, rb_node);
278 rb_erase(&state->rb_node, &tree->state);
279 RB_CLEAR_NODE(&state->rb_node);
280 /*
281 * btree io trees aren't supposed to have tasks waiting for
282 * changes in the flags of extent states ever.
283 */
284 ASSERT(!waitqueue_active(&state->wq));
285 free_extent_state(state);
286
287 cond_resched_lock(&tree->lock);
288 }
289 spin_unlock(&tree->lock);
290}
291
292static struct extent_state *alloc_extent_state(gfp_t mask)
293{
294 struct extent_state *state;
295
296 /*
297 * The given mask might be not appropriate for the slab allocator,
298 * drop the unsupported bits
299 */
300 mask &= ~(__GFP_DMA32|__GFP_HIGHMEM);
301 state = kmem_cache_alloc(extent_state_cache, mask);
302 if (!state)
303 return state;
304 state->state = 0;
305 state->failrec = NULL;
306 RB_CLEAR_NODE(&state->rb_node);
307 btrfs_leak_debug_add(&state->leak_list, &states);
308 refcount_set(&state->refs, 1);
309 init_waitqueue_head(&state->wq);
310 trace_alloc_extent_state(state, mask, _RET_IP_);
311 return state;
312}
313
314void free_extent_state(struct extent_state *state)
315{
316 if (!state)
317 return;
318 if (refcount_dec_and_test(&state->refs)) {
319 WARN_ON(extent_state_in_tree(state));
320 btrfs_leak_debug_del(&state->leak_list);
321 trace_free_extent_state(state, _RET_IP_);
322 kmem_cache_free(extent_state_cache, state);
323 }
324}
325
326static struct rb_node *tree_insert(struct rb_root *root,
327 struct rb_node *search_start,
328 u64 offset,
329 struct rb_node *node,
330 struct rb_node ***p_in,
331 struct rb_node **parent_in)
332{
333 struct rb_node **p;
334 struct rb_node *parent = NULL;
335 struct tree_entry *entry;
336
337 if (p_in && parent_in) {
338 p = *p_in;
339 parent = *parent_in;
340 goto do_insert;
341 }
342
343 p = search_start ? &search_start : &root->rb_node;
344 while (*p) {
345 parent = *p;
346 entry = rb_entry(parent, struct tree_entry, rb_node);
347
348 if (offset < entry->start)
349 p = &(*p)->rb_left;
350 else if (offset > entry->end)
351 p = &(*p)->rb_right;
352 else
353 return parent;
354 }
355
356do_insert:
357 rb_link_node(node, parent, p);
358 rb_insert_color(node, root);
359 return NULL;
360}
361
362/**
363 * __etree_search - searche @tree for an entry that contains @offset. Such
364 * entry would have entry->start <= offset && entry->end >= offset.
365 *
366 * @tree - the tree to search
367 * @offset - offset that should fall within an entry in @tree
368 * @next_ret - pointer to the first entry whose range ends after @offset
369 * @prev - pointer to the first entry whose range begins before @offset
370 * @p_ret - pointer where new node should be anchored (used when inserting an
371 * entry in the tree)
372 * @parent_ret - points to entry which would have been the parent of the entry,
373 * containing @offset
374 *
375 * This function returns a pointer to the entry that contains @offset byte
376 * address. If no such entry exists, then NULL is returned and the other
377 * pointer arguments to the function are filled, otherwise the found entry is
378 * returned and other pointers are left untouched.
379 */
380static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
381 struct rb_node **next_ret,
382 struct rb_node **prev_ret,
383 struct rb_node ***p_ret,
384 struct rb_node **parent_ret)
385{
386 struct rb_root *root = &tree->state;
387 struct rb_node **n = &root->rb_node;
388 struct rb_node *prev = NULL;
389 struct rb_node *orig_prev = NULL;
390 struct tree_entry *entry;
391 struct tree_entry *prev_entry = NULL;
392
393 while (*n) {
394 prev = *n;
395 entry = rb_entry(prev, struct tree_entry, rb_node);
396 prev_entry = entry;
397
398 if (offset < entry->start)
399 n = &(*n)->rb_left;
400 else if (offset > entry->end)
401 n = &(*n)->rb_right;
402 else
403 return *n;
404 }
405
406 if (p_ret)
407 *p_ret = n;
408 if (parent_ret)
409 *parent_ret = prev;
410
411 if (next_ret) {
412 orig_prev = prev;
413 while (prev && offset > prev_entry->end) {
414 prev = rb_next(prev);
415 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
416 }
417 *next_ret = prev;
418 prev = orig_prev;
419 }
420
421 if (prev_ret) {
422 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
423 while (prev && offset < prev_entry->start) {
424 prev = rb_prev(prev);
425 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
426 }
427 *prev_ret = prev;
428 }
429 return NULL;
430}
431
432static inline struct rb_node *
433tree_search_for_insert(struct extent_io_tree *tree,
434 u64 offset,
435 struct rb_node ***p_ret,
436 struct rb_node **parent_ret)
437{
438 struct rb_node *next= NULL;
439 struct rb_node *ret;
440
441 ret = __etree_search(tree, offset, &next, NULL, p_ret, parent_ret);
442 if (!ret)
443 return next;
444 return ret;
445}
446
447static inline struct rb_node *tree_search(struct extent_io_tree *tree,
448 u64 offset)
449{
450 return tree_search_for_insert(tree, offset, NULL, NULL);
451}
452
453/*
454 * utility function to look for merge candidates inside a given range.
455 * Any extents with matching state are merged together into a single
456 * extent in the tree. Extents with EXTENT_IO in their state field
457 * are not merged because the end_io handlers need to be able to do
458 * operations on them without sleeping (or doing allocations/splits).
459 *
460 * This should be called with the tree lock held.
461 */
462static void merge_state(struct extent_io_tree *tree,
463 struct extent_state *state)
464{
465 struct extent_state *other;
466 struct rb_node *other_node;
467
468 if (state->state & (EXTENT_LOCKED | EXTENT_BOUNDARY))
469 return;
470
471 other_node = rb_prev(&state->rb_node);
472 if (other_node) {
473 other = rb_entry(other_node, struct extent_state, rb_node);
474 if (other->end == state->start - 1 &&
475 other->state == state->state) {
476 if (tree->private_data &&
477 is_data_inode(tree->private_data))
478 btrfs_merge_delalloc_extent(tree->private_data,
479 state, other);
480 state->start = other->start;
481 rb_erase(&other->rb_node, &tree->state);
482 RB_CLEAR_NODE(&other->rb_node);
483 free_extent_state(other);
484 }
485 }
486 other_node = rb_next(&state->rb_node);
487 if (other_node) {
488 other = rb_entry(other_node, struct extent_state, rb_node);
489 if (other->start == state->end + 1 &&
490 other->state == state->state) {
491 if (tree->private_data &&
492 is_data_inode(tree->private_data))
493 btrfs_merge_delalloc_extent(tree->private_data,
494 state, other);
495 state->end = other->end;
496 rb_erase(&other->rb_node, &tree->state);
497 RB_CLEAR_NODE(&other->rb_node);
498 free_extent_state(other);
499 }
500 }
501}
502
503static void set_state_bits(struct extent_io_tree *tree,
504 struct extent_state *state, unsigned *bits,
505 struct extent_changeset *changeset);
506
507/*
508 * insert an extent_state struct into the tree. 'bits' are set on the
509 * struct before it is inserted.
510 *
511 * This may return -EEXIST if the extent is already there, in which case the
512 * state struct is freed.
513 *
514 * The tree lock is not taken internally. This is a utility function and
515 * probably isn't what you want to call (see set/clear_extent_bit).
516 */
517static int insert_state(struct extent_io_tree *tree,
518 struct extent_state *state, u64 start, u64 end,
519 struct rb_node ***p,
520 struct rb_node **parent,
521 unsigned *bits, struct extent_changeset *changeset)
522{
523 struct rb_node *node;
524
525 if (end < start) {
526 btrfs_err(tree->fs_info,
527 "insert state: end < start %llu %llu", end, start);
528 WARN_ON(1);
529 }
530 state->start = start;
531 state->end = end;
532
533 set_state_bits(tree, state, bits, changeset);
534
535 node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
536 if (node) {
537 struct extent_state *found;
538 found = rb_entry(node, struct extent_state, rb_node);
539 btrfs_err(tree->fs_info,
540 "found node %llu %llu on insert of %llu %llu",
541 found->start, found->end, start, end);
542 return -EEXIST;
543 }
544 merge_state(tree, state);
545 return 0;
546}
547
548/*
549 * split a given extent state struct in two, inserting the preallocated
550 * struct 'prealloc' as the newly created second half. 'split' indicates an
551 * offset inside 'orig' where it should be split.
552 *
553 * Before calling,
554 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
555 * are two extent state structs in the tree:
556 * prealloc: [orig->start, split - 1]
557 * orig: [ split, orig->end ]
558 *
559 * The tree locks are not taken by this function. They need to be held
560 * by the caller.
561 */
562static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
563 struct extent_state *prealloc, u64 split)
564{
565 struct rb_node *node;
566
567 if (tree->private_data && is_data_inode(tree->private_data))
568 btrfs_split_delalloc_extent(tree->private_data, orig, split);
569
570 prealloc->start = orig->start;
571 prealloc->end = split - 1;
572 prealloc->state = orig->state;
573 orig->start = split;
574
575 node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
576 &prealloc->rb_node, NULL, NULL);
577 if (node) {
578 free_extent_state(prealloc);
579 return -EEXIST;
580 }
581 return 0;
582}
583
584static struct extent_state *next_state(struct extent_state *state)
585{
586 struct rb_node *next = rb_next(&state->rb_node);
587 if (next)
588 return rb_entry(next, struct extent_state, rb_node);
589 else
590 return NULL;
591}
592
593/*
594 * utility function to clear some bits in an extent state struct.
595 * it will optionally wake up anyone waiting on this state (wake == 1).
596 *
597 * If no bits are set on the state struct after clearing things, the
598 * struct is freed and removed from the tree
599 */
600static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
601 struct extent_state *state,
602 unsigned *bits, int wake,
603 struct extent_changeset *changeset)
604{
605 struct extent_state *next;
606 unsigned bits_to_clear = *bits & ~EXTENT_CTLBITS;
607 int ret;
608
609 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
610 u64 range = state->end - state->start + 1;
611 WARN_ON(range > tree->dirty_bytes);
612 tree->dirty_bytes -= range;
613 }
614
615 if (tree->private_data && is_data_inode(tree->private_data))
616 btrfs_clear_delalloc_extent(tree->private_data, state, bits);
617
618 ret = add_extent_changeset(state, bits_to_clear, changeset, 0);
619 BUG_ON(ret < 0);
620 state->state &= ~bits_to_clear;
621 if (wake)
622 wake_up(&state->wq);
623 if (state->state == 0) {
624 next = next_state(state);
625 if (extent_state_in_tree(state)) {
626 rb_erase(&state->rb_node, &tree->state);
627 RB_CLEAR_NODE(&state->rb_node);
628 free_extent_state(state);
629 } else {
630 WARN_ON(1);
631 }
632 } else {
633 merge_state(tree, state);
634 next = next_state(state);
635 }
636 return next;
637}
638
639static struct extent_state *
640alloc_extent_state_atomic(struct extent_state *prealloc)
641{
642 if (!prealloc)
643 prealloc = alloc_extent_state(GFP_ATOMIC);
644
645 return prealloc;
646}
647
648static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
649{
650 struct inode *inode = tree->private_data;
651
652 btrfs_panic(btrfs_sb(inode->i_sb), err,
653 "locking error: extent tree was modified by another thread while locked");
654}
655
656/*
657 * clear some bits on a range in the tree. This may require splitting
658 * or inserting elements in the tree, so the gfp mask is used to
659 * indicate which allocations or sleeping are allowed.
660 *
661 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
662 * the given range from the tree regardless of state (ie for truncate).
663 *
664 * the range [start, end] is inclusive.
665 *
666 * This takes the tree lock, and returns 0 on success and < 0 on error.
667 */
668int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
669 unsigned bits, int wake, int delete,
670 struct extent_state **cached_state,
671 gfp_t mask, struct extent_changeset *changeset)
672{
673 struct extent_state *state;
674 struct extent_state *cached;
675 struct extent_state *prealloc = NULL;
676 struct rb_node *node;
677 u64 last_end;
678 int err;
679 int clear = 0;
680
681 btrfs_debug_check_extent_io_range(tree, start, end);
682 trace_btrfs_clear_extent_bit(tree, start, end - start + 1, bits);
683
684 if (bits & EXTENT_DELALLOC)
685 bits |= EXTENT_NORESERVE;
686
687 if (delete)
688 bits |= ~EXTENT_CTLBITS;
689
690 if (bits & (EXTENT_LOCKED | EXTENT_BOUNDARY))
691 clear = 1;
692again:
693 if (!prealloc && gfpflags_allow_blocking(mask)) {
694 /*
695 * Don't care for allocation failure here because we might end
696 * up not needing the pre-allocated extent state at all, which
697 * is the case if we only have in the tree extent states that
698 * cover our input range and don't cover too any other range.
699 * If we end up needing a new extent state we allocate it later.
700 */
701 prealloc = alloc_extent_state(mask);
702 }
703
704 spin_lock(&tree->lock);
705 if (cached_state) {
706 cached = *cached_state;
707
708 if (clear) {
709 *cached_state = NULL;
710 cached_state = NULL;
711 }
712
713 if (cached && extent_state_in_tree(cached) &&
714 cached->start <= start && cached->end > start) {
715 if (clear)
716 refcount_dec(&cached->refs);
717 state = cached;
718 goto hit_next;
719 }
720 if (clear)
721 free_extent_state(cached);
722 }
723 /*
724 * this search will find the extents that end after
725 * our range starts
726 */
727 node = tree_search(tree, start);
728 if (!node)
729 goto out;
730 state = rb_entry(node, struct extent_state, rb_node);
731hit_next:
732 if (state->start > end)
733 goto out;
734 WARN_ON(state->end < start);
735 last_end = state->end;
736
737 /* the state doesn't have the wanted bits, go ahead */
738 if (!(state->state & bits)) {
739 state = next_state(state);
740 goto next;
741 }
742
743 /*
744 * | ---- desired range ---- |
745 * | state | or
746 * | ------------- state -------------- |
747 *
748 * We need to split the extent we found, and may flip
749 * bits on second half.
750 *
751 * If the extent we found extends past our range, we
752 * just split and search again. It'll get split again
753 * the next time though.
754 *
755 * If the extent we found is inside our range, we clear
756 * the desired bit on it.
757 */
758
759 if (state->start < start) {
760 prealloc = alloc_extent_state_atomic(prealloc);
761 BUG_ON(!prealloc);
762 err = split_state(tree, state, prealloc, start);
763 if (err)
764 extent_io_tree_panic(tree, err);
765
766 prealloc = NULL;
767 if (err)
768 goto out;
769 if (state->end <= end) {
770 state = clear_state_bit(tree, state, &bits, wake,
771 changeset);
772 goto next;
773 }
774 goto search_again;
775 }
776 /*
777 * | ---- desired range ---- |
778 * | state |
779 * We need to split the extent, and clear the bit
780 * on the first half
781 */
782 if (state->start <= end && state->end > end) {
783 prealloc = alloc_extent_state_atomic(prealloc);
784 BUG_ON(!prealloc);
785 err = split_state(tree, state, prealloc, end + 1);
786 if (err)
787 extent_io_tree_panic(tree, err);
788
789 if (wake)
790 wake_up(&state->wq);
791
792 clear_state_bit(tree, prealloc, &bits, wake, changeset);
793
794 prealloc = NULL;
795 goto out;
796 }
797
798 state = clear_state_bit(tree, state, &bits, wake, changeset);
799next:
800 if (last_end == (u64)-1)
801 goto out;
802 start = last_end + 1;
803 if (start <= end && state && !need_resched())
804 goto hit_next;
805
806search_again:
807 if (start > end)
808 goto out;
809 spin_unlock(&tree->lock);
810 if (gfpflags_allow_blocking(mask))
811 cond_resched();
812 goto again;
813
814out:
815 spin_unlock(&tree->lock);
816 if (prealloc)
817 free_extent_state(prealloc);
818
819 return 0;
820
821}
822
823static void wait_on_state(struct extent_io_tree *tree,
824 struct extent_state *state)
825 __releases(tree->lock)
826 __acquires(tree->lock)
827{
828 DEFINE_WAIT(wait);
829 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
830 spin_unlock(&tree->lock);
831 schedule();
832 spin_lock(&tree->lock);
833 finish_wait(&state->wq, &wait);
834}
835
836/*
837 * waits for one or more bits to clear on a range in the state tree.
838 * The range [start, end] is inclusive.
839 * The tree lock is taken by this function
840 */
841static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
842 unsigned long bits)
843{
844 struct extent_state *state;
845 struct rb_node *node;
846
847 btrfs_debug_check_extent_io_range(tree, start, end);
848
849 spin_lock(&tree->lock);
850again:
851 while (1) {
852 /*
853 * this search will find all the extents that end after
854 * our range starts
855 */
856 node = tree_search(tree, start);
857process_node:
858 if (!node)
859 break;
860
861 state = rb_entry(node, struct extent_state, rb_node);
862
863 if (state->start > end)
864 goto out;
865
866 if (state->state & bits) {
867 start = state->start;
868 refcount_inc(&state->refs);
869 wait_on_state(tree, state);
870 free_extent_state(state);
871 goto again;
872 }
873 start = state->end + 1;
874
875 if (start > end)
876 break;
877
878 if (!cond_resched_lock(&tree->lock)) {
879 node = rb_next(node);
880 goto process_node;
881 }
882 }
883out:
884 spin_unlock(&tree->lock);
885}
886
887static void set_state_bits(struct extent_io_tree *tree,
888 struct extent_state *state,
889 unsigned *bits, struct extent_changeset *changeset)
890{
891 unsigned bits_to_set = *bits & ~EXTENT_CTLBITS;
892 int ret;
893
894 if (tree->private_data && is_data_inode(tree->private_data))
895 btrfs_set_delalloc_extent(tree->private_data, state, bits);
896
897 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
898 u64 range = state->end - state->start + 1;
899 tree->dirty_bytes += range;
900 }
901 ret = add_extent_changeset(state, bits_to_set, changeset, 1);
902 BUG_ON(ret < 0);
903 state->state |= bits_to_set;
904}
905
906static void cache_state_if_flags(struct extent_state *state,
907 struct extent_state **cached_ptr,
908 unsigned flags)
909{
910 if (cached_ptr && !(*cached_ptr)) {
911 if (!flags || (state->state & flags)) {
912 *cached_ptr = state;
913 refcount_inc(&state->refs);
914 }
915 }
916}
917
918static void cache_state(struct extent_state *state,
919 struct extent_state **cached_ptr)
920{
921 return cache_state_if_flags(state, cached_ptr,
922 EXTENT_LOCKED | EXTENT_BOUNDARY);
923}
924
925/*
926 * set some bits on a range in the tree. This may require allocations or
927 * sleeping, so the gfp mask is used to indicate what is allowed.
928 *
929 * If any of the exclusive bits are set, this will fail with -EEXIST if some
930 * part of the range already has the desired bits set. The start of the
931 * existing range is returned in failed_start in this case.
932 *
933 * [start, end] is inclusive This takes the tree lock.
934 */
935
936static int __must_check
937__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
938 unsigned bits, unsigned exclusive_bits,
939 u64 *failed_start, struct extent_state **cached_state,
940 gfp_t mask, struct extent_changeset *changeset)
941{
942 struct extent_state *state;
943 struct extent_state *prealloc = NULL;
944 struct rb_node *node;
945 struct rb_node **p;
946 struct rb_node *parent;
947 int err = 0;
948 u64 last_start;
949 u64 last_end;
950
951 btrfs_debug_check_extent_io_range(tree, start, end);
952 trace_btrfs_set_extent_bit(tree, start, end - start + 1, bits);
953
954again:
955 if (!prealloc && gfpflags_allow_blocking(mask)) {
956 /*
957 * Don't care for allocation failure here because we might end
958 * up not needing the pre-allocated extent state at all, which
959 * is the case if we only have in the tree extent states that
960 * cover our input range and don't cover too any other range.
961 * If we end up needing a new extent state we allocate it later.
962 */
963 prealloc = alloc_extent_state(mask);
964 }
965
966 spin_lock(&tree->lock);
967 if (cached_state && *cached_state) {
968 state = *cached_state;
969 if (state->start <= start && state->end > start &&
970 extent_state_in_tree(state)) {
971 node = &state->rb_node;
972 goto hit_next;
973 }
974 }
975 /*
976 * this search will find all the extents that end after
977 * our range starts.
978 */
979 node = tree_search_for_insert(tree, start, &p, &parent);
980 if (!node) {
981 prealloc = alloc_extent_state_atomic(prealloc);
982 BUG_ON(!prealloc);
983 err = insert_state(tree, prealloc, start, end,
984 &p, &parent, &bits, changeset);
985 if (err)
986 extent_io_tree_panic(tree, err);
987
988 cache_state(prealloc, cached_state);
989 prealloc = NULL;
990 goto out;
991 }
992 state = rb_entry(node, struct extent_state, rb_node);
993hit_next:
994 last_start = state->start;
995 last_end = state->end;
996
997 /*
998 * | ---- desired range ---- |
999 * | state |
1000 *
1001 * Just lock what we found and keep going
1002 */
1003 if (state->start == start && state->end <= end) {
1004 if (state->state & exclusive_bits) {
1005 *failed_start = state->start;
1006 err = -EEXIST;
1007 goto out;
1008 }
1009
1010 set_state_bits(tree, state, &bits, changeset);
1011 cache_state(state, cached_state);
1012 merge_state(tree, state);
1013 if (last_end == (u64)-1)
1014 goto out;
1015 start = last_end + 1;
1016 state = next_state(state);
1017 if (start < end && state && state->start == start &&
1018 !need_resched())
1019 goto hit_next;
1020 goto search_again;
1021 }
1022
1023 /*
1024 * | ---- desired range ---- |
1025 * | state |
1026 * or
1027 * | ------------- state -------------- |
1028 *
1029 * We need to split the extent we found, and may flip bits on
1030 * second half.
1031 *
1032 * If the extent we found extends past our
1033 * range, we just split and search again. It'll get split
1034 * again the next time though.
1035 *
1036 * If the extent we found is inside our range, we set the
1037 * desired bit on it.
1038 */
1039 if (state->start < start) {
1040 if (state->state & exclusive_bits) {
1041 *failed_start = start;
1042 err = -EEXIST;
1043 goto out;
1044 }
1045
1046 prealloc = alloc_extent_state_atomic(prealloc);
1047 BUG_ON(!prealloc);
1048 err = split_state(tree, state, prealloc, start);
1049 if (err)
1050 extent_io_tree_panic(tree, err);
1051
1052 prealloc = NULL;
1053 if (err)
1054 goto out;
1055 if (state->end <= end) {
1056 set_state_bits(tree, state, &bits, changeset);
1057 cache_state(state, cached_state);
1058 merge_state(tree, state);
1059 if (last_end == (u64)-1)
1060 goto out;
1061 start = last_end + 1;
1062 state = next_state(state);
1063 if (start < end && state && state->start == start &&
1064 !need_resched())
1065 goto hit_next;
1066 }
1067 goto search_again;
1068 }
1069 /*
1070 * | ---- desired range ---- |
1071 * | state | or | state |
1072 *
1073 * There's a hole, we need to insert something in it and
1074 * ignore the extent we found.
1075 */
1076 if (state->start > start) {
1077 u64 this_end;
1078 if (end < last_start)
1079 this_end = end;
1080 else
1081 this_end = last_start - 1;
1082
1083 prealloc = alloc_extent_state_atomic(prealloc);
1084 BUG_ON(!prealloc);
1085
1086 /*
1087 * Avoid to free 'prealloc' if it can be merged with
1088 * the later extent.
1089 */
1090 err = insert_state(tree, prealloc, start, this_end,
1091 NULL, NULL, &bits, changeset);
1092 if (err)
1093 extent_io_tree_panic(tree, err);
1094
1095 cache_state(prealloc, cached_state);
1096 prealloc = NULL;
1097 start = this_end + 1;
1098 goto search_again;
1099 }
1100 /*
1101 * | ---- desired range ---- |
1102 * | state |
1103 * We need to split the extent, and set the bit
1104 * on the first half
1105 */
1106 if (state->start <= end && state->end > end) {
1107 if (state->state & exclusive_bits) {
1108 *failed_start = start;
1109 err = -EEXIST;
1110 goto out;
1111 }
1112
1113 prealloc = alloc_extent_state_atomic(prealloc);
1114 BUG_ON(!prealloc);
1115 err = split_state(tree, state, prealloc, end + 1);
1116 if (err)
1117 extent_io_tree_panic(tree, err);
1118
1119 set_state_bits(tree, prealloc, &bits, changeset);
1120 cache_state(prealloc, cached_state);
1121 merge_state(tree, prealloc);
1122 prealloc = NULL;
1123 goto out;
1124 }
1125
1126search_again:
1127 if (start > end)
1128 goto out;
1129 spin_unlock(&tree->lock);
1130 if (gfpflags_allow_blocking(mask))
1131 cond_resched();
1132 goto again;
1133
1134out:
1135 spin_unlock(&tree->lock);
1136 if (prealloc)
1137 free_extent_state(prealloc);
1138
1139 return err;
1140
1141}
1142
1143int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1144 unsigned bits, u64 * failed_start,
1145 struct extent_state **cached_state, gfp_t mask)
1146{
1147 return __set_extent_bit(tree, start, end, bits, 0, failed_start,
1148 cached_state, mask, NULL);
1149}
1150
1151
1152/**
1153 * convert_extent_bit - convert all bits in a given range from one bit to
1154 * another
1155 * @tree: the io tree to search
1156 * @start: the start offset in bytes
1157 * @end: the end offset in bytes (inclusive)
1158 * @bits: the bits to set in this range
1159 * @clear_bits: the bits to clear in this range
1160 * @cached_state: state that we're going to cache
1161 *
1162 * This will go through and set bits for the given range. If any states exist
1163 * already in this range they are set with the given bit and cleared of the
1164 * clear_bits. This is only meant to be used by things that are mergeable, ie
1165 * converting from say DELALLOC to DIRTY. This is not meant to be used with
1166 * boundary bits like LOCK.
1167 *
1168 * All allocations are done with GFP_NOFS.
1169 */
1170int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1171 unsigned bits, unsigned clear_bits,
1172 struct extent_state **cached_state)
1173{
1174 struct extent_state *state;
1175 struct extent_state *prealloc = NULL;
1176 struct rb_node *node;
1177 struct rb_node **p;
1178 struct rb_node *parent;
1179 int err = 0;
1180 u64 last_start;
1181 u64 last_end;
1182 bool first_iteration = true;
1183
1184 btrfs_debug_check_extent_io_range(tree, start, end);
1185 trace_btrfs_convert_extent_bit(tree, start, end - start + 1, bits,
1186 clear_bits);
1187
1188again:
1189 if (!prealloc) {
1190 /*
1191 * Best effort, don't worry if extent state allocation fails
1192 * here for the first iteration. We might have a cached state
1193 * that matches exactly the target range, in which case no
1194 * extent state allocations are needed. We'll only know this
1195 * after locking the tree.
1196 */
1197 prealloc = alloc_extent_state(GFP_NOFS);
1198 if (!prealloc && !first_iteration)
1199 return -ENOMEM;
1200 }
1201
1202 spin_lock(&tree->lock);
1203 if (cached_state && *cached_state) {
1204 state = *cached_state;
1205 if (state->start <= start && state->end > start &&
1206 extent_state_in_tree(state)) {
1207 node = &state->rb_node;
1208 goto hit_next;
1209 }
1210 }
1211
1212 /*
1213 * this search will find all the extents that end after
1214 * our range starts.
1215 */
1216 node = tree_search_for_insert(tree, start, &p, &parent);
1217 if (!node) {
1218 prealloc = alloc_extent_state_atomic(prealloc);
1219 if (!prealloc) {
1220 err = -ENOMEM;
1221 goto out;
1222 }
1223 err = insert_state(tree, prealloc, start, end,
1224 &p, &parent, &bits, NULL);
1225 if (err)
1226 extent_io_tree_panic(tree, err);
1227 cache_state(prealloc, cached_state);
1228 prealloc = NULL;
1229 goto out;
1230 }
1231 state = rb_entry(node, struct extent_state, rb_node);
1232hit_next:
1233 last_start = state->start;
1234 last_end = state->end;
1235
1236 /*
1237 * | ---- desired range ---- |
1238 * | state |
1239 *
1240 * Just lock what we found and keep going
1241 */
1242 if (state->start == start && state->end <= end) {
1243 set_state_bits(tree, state, &bits, NULL);
1244 cache_state(state, cached_state);
1245 state = clear_state_bit(tree, state, &clear_bits, 0, NULL);
1246 if (last_end == (u64)-1)
1247 goto out;
1248 start = last_end + 1;
1249 if (start < end && state && state->start == start &&
1250 !need_resched())
1251 goto hit_next;
1252 goto search_again;
1253 }
1254
1255 /*
1256 * | ---- desired range ---- |
1257 * | state |
1258 * or
1259 * | ------------- state -------------- |
1260 *
1261 * We need to split the extent we found, and may flip bits on
1262 * second half.
1263 *
1264 * If the extent we found extends past our
1265 * range, we just split and search again. It'll get split
1266 * again the next time though.
1267 *
1268 * If the extent we found is inside our range, we set the
1269 * desired bit on it.
1270 */
1271 if (state->start < start) {
1272 prealloc = alloc_extent_state_atomic(prealloc);
1273 if (!prealloc) {
1274 err = -ENOMEM;
1275 goto out;
1276 }
1277 err = split_state(tree, state, prealloc, start);
1278 if (err)
1279 extent_io_tree_panic(tree, err);
1280 prealloc = NULL;
1281 if (err)
1282 goto out;
1283 if (state->end <= end) {
1284 set_state_bits(tree, state, &bits, NULL);
1285 cache_state(state, cached_state);
1286 state = clear_state_bit(tree, state, &clear_bits, 0,
1287 NULL);
1288 if (last_end == (u64)-1)
1289 goto out;
1290 start = last_end + 1;
1291 if (start < end && state && state->start == start &&
1292 !need_resched())
1293 goto hit_next;
1294 }
1295 goto search_again;
1296 }
1297 /*
1298 * | ---- desired range ---- |
1299 * | state | or | state |
1300 *
1301 * There's a hole, we need to insert something in it and
1302 * ignore the extent we found.
1303 */
1304 if (state->start > start) {
1305 u64 this_end;
1306 if (end < last_start)
1307 this_end = end;
1308 else
1309 this_end = last_start - 1;
1310
1311 prealloc = alloc_extent_state_atomic(prealloc);
1312 if (!prealloc) {
1313 err = -ENOMEM;
1314 goto out;
1315 }
1316
1317 /*
1318 * Avoid to free 'prealloc' if it can be merged with
1319 * the later extent.
1320 */
1321 err = insert_state(tree, prealloc, start, this_end,
1322 NULL, NULL, &bits, NULL);
1323 if (err)
1324 extent_io_tree_panic(tree, err);
1325 cache_state(prealloc, cached_state);
1326 prealloc = NULL;
1327 start = this_end + 1;
1328 goto search_again;
1329 }
1330 /*
1331 * | ---- desired range ---- |
1332 * | state |
1333 * We need to split the extent, and set the bit
1334 * on the first half
1335 */
1336 if (state->start <= end && state->end > end) {
1337 prealloc = alloc_extent_state_atomic(prealloc);
1338 if (!prealloc) {
1339 err = -ENOMEM;
1340 goto out;
1341 }
1342
1343 err = split_state(tree, state, prealloc, end + 1);
1344 if (err)
1345 extent_io_tree_panic(tree, err);
1346
1347 set_state_bits(tree, prealloc, &bits, NULL);
1348 cache_state(prealloc, cached_state);
1349 clear_state_bit(tree, prealloc, &clear_bits, 0, NULL);
1350 prealloc = NULL;
1351 goto out;
1352 }
1353
1354search_again:
1355 if (start > end)
1356 goto out;
1357 spin_unlock(&tree->lock);
1358 cond_resched();
1359 first_iteration = false;
1360 goto again;
1361
1362out:
1363 spin_unlock(&tree->lock);
1364 if (prealloc)
1365 free_extent_state(prealloc);
1366
1367 return err;
1368}
1369
1370/* wrappers around set/clear extent bit */
1371int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1372 unsigned bits, struct extent_changeset *changeset)
1373{
1374 /*
1375 * We don't support EXTENT_LOCKED yet, as current changeset will
1376 * record any bits changed, so for EXTENT_LOCKED case, it will
1377 * either fail with -EEXIST or changeset will record the whole
1378 * range.
1379 */
1380 BUG_ON(bits & EXTENT_LOCKED);
1381
1382 return __set_extent_bit(tree, start, end, bits, 0, NULL, NULL, GFP_NOFS,
1383 changeset);
1384}
1385
1386int set_extent_bits_nowait(struct extent_io_tree *tree, u64 start, u64 end,
1387 unsigned bits)
1388{
1389 return __set_extent_bit(tree, start, end, bits, 0, NULL, NULL,
1390 GFP_NOWAIT, NULL);
1391}
1392
1393int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1394 unsigned bits, int wake, int delete,
1395 struct extent_state **cached)
1396{
1397 return __clear_extent_bit(tree, start, end, bits, wake, delete,
1398 cached, GFP_NOFS, NULL);
1399}
1400
1401int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1402 unsigned bits, struct extent_changeset *changeset)
1403{
1404 /*
1405 * Don't support EXTENT_LOCKED case, same reason as
1406 * set_record_extent_bits().
1407 */
1408 BUG_ON(bits & EXTENT_LOCKED);
1409
1410 return __clear_extent_bit(tree, start, end, bits, 0, 0, NULL, GFP_NOFS,
1411 changeset);
1412}
1413
1414/*
1415 * either insert or lock state struct between start and end use mask to tell
1416 * us if waiting is desired.
1417 */
1418int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1419 struct extent_state **cached_state)
1420{
1421 int err;
1422 u64 failed_start;
1423
1424 while (1) {
1425 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED,
1426 EXTENT_LOCKED, &failed_start,
1427 cached_state, GFP_NOFS, NULL);
1428 if (err == -EEXIST) {
1429 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
1430 start = failed_start;
1431 } else
1432 break;
1433 WARN_ON(start > end);
1434 }
1435 return err;
1436}
1437
1438int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1439{
1440 int err;
1441 u64 failed_start;
1442
1443 err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1444 &failed_start, NULL, GFP_NOFS, NULL);
1445 if (err == -EEXIST) {
1446 if (failed_start > start)
1447 clear_extent_bit(tree, start, failed_start - 1,
1448 EXTENT_LOCKED, 1, 0, NULL);
1449 return 0;
1450 }
1451 return 1;
1452}
1453
1454void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
1455{
1456 unsigned long index = start >> PAGE_SHIFT;
1457 unsigned long end_index = end >> PAGE_SHIFT;
1458 struct page *page;
1459
1460 while (index <= end_index) {
1461 page = find_get_page(inode->i_mapping, index);
1462 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1463 clear_page_dirty_for_io(page);
1464 put_page(page);
1465 index++;
1466 }
1467}
1468
1469void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
1470{
1471 unsigned long index = start >> PAGE_SHIFT;
1472 unsigned long end_index = end >> PAGE_SHIFT;
1473 struct page *page;
1474
1475 while (index <= end_index) {
1476 page = find_get_page(inode->i_mapping, index);
1477 BUG_ON(!page); /* Pages should be in the extent_io_tree */
1478 __set_page_dirty_nobuffers(page);
1479 account_page_redirty(page);
1480 put_page(page);
1481 index++;
1482 }
1483}
1484
1485/* find the first state struct with 'bits' set after 'start', and
1486 * return it. tree->lock must be held. NULL will returned if
1487 * nothing was found after 'start'
1488 */
1489static struct extent_state *
1490find_first_extent_bit_state(struct extent_io_tree *tree,
1491 u64 start, unsigned bits)
1492{
1493 struct rb_node *node;
1494 struct extent_state *state;
1495
1496 /*
1497 * this search will find all the extents that end after
1498 * our range starts.
1499 */
1500 node = tree_search(tree, start);
1501 if (!node)
1502 goto out;
1503
1504 while (1) {
1505 state = rb_entry(node, struct extent_state, rb_node);
1506 if (state->end >= start && (state->state & bits))
1507 return state;
1508
1509 node = rb_next(node);
1510 if (!node)
1511 break;
1512 }
1513out:
1514 return NULL;
1515}
1516
1517/*
1518 * find the first offset in the io tree with 'bits' set. zero is
1519 * returned if we find something, and *start_ret and *end_ret are
1520 * set to reflect the state struct that was found.
1521 *
1522 * If nothing was found, 1 is returned. If found something, return 0.
1523 */
1524int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1525 u64 *start_ret, u64 *end_ret, unsigned bits,
1526 struct extent_state **cached_state)
1527{
1528 struct extent_state *state;
1529 int ret = 1;
1530
1531 spin_lock(&tree->lock);
1532 if (cached_state && *cached_state) {
1533 state = *cached_state;
1534 if (state->end == start - 1 && extent_state_in_tree(state)) {
1535 while ((state = next_state(state)) != NULL) {
1536 if (state->state & bits)
1537 goto got_it;
1538 }
1539 free_extent_state(*cached_state);
1540 *cached_state = NULL;
1541 goto out;
1542 }
1543 free_extent_state(*cached_state);
1544 *cached_state = NULL;
1545 }
1546
1547 state = find_first_extent_bit_state(tree, start, bits);
1548got_it:
1549 if (state) {
1550 cache_state_if_flags(state, cached_state, 0);
1551 *start_ret = state->start;
1552 *end_ret = state->end;
1553 ret = 0;
1554 }
1555out:
1556 spin_unlock(&tree->lock);
1557 return ret;
1558}
1559
1560/**
1561 * find_first_clear_extent_bit - find the first range that has @bits not set.
1562 * This range could start before @start.
1563 *
1564 * @tree - the tree to search
1565 * @start - the offset at/after which the found extent should start
1566 * @start_ret - records the beginning of the range
1567 * @end_ret - records the end of the range (inclusive)
1568 * @bits - the set of bits which must be unset
1569 *
1570 * Since unallocated range is also considered one which doesn't have the bits
1571 * set it's possible that @end_ret contains -1, this happens in case the range
1572 * spans (last_range_end, end of device]. In this case it's up to the caller to
1573 * trim @end_ret to the appropriate size.
1574 */
1575void find_first_clear_extent_bit(struct extent_io_tree *tree, u64 start,
1576 u64 *start_ret, u64 *end_ret, unsigned bits)
1577{
1578 struct extent_state *state;
1579 struct rb_node *node, *prev = NULL, *next;
1580
1581 spin_lock(&tree->lock);
1582
1583 /* Find first extent with bits cleared */
1584 while (1) {
1585 node = __etree_search(tree, start, &next, &prev, NULL, NULL);
1586 if (!node) {
1587 node = next;
1588 if (!node) {
1589 /*
1590 * We are past the last allocated chunk,
1591 * set start at the end of the last extent. The
1592 * device alloc tree should never be empty so
1593 * prev is always set.
1594 */
1595 ASSERT(prev);
1596 state = rb_entry(prev, struct extent_state, rb_node);
1597 *start_ret = state->end + 1;
1598 *end_ret = -1;
1599 goto out;
1600 }
1601 }
1602 /*
1603 * At this point 'node' either contains 'start' or start is
1604 * before 'node'
1605 */
1606 state = rb_entry(node, struct extent_state, rb_node);
1607
1608 if (in_range(start, state->start, state->end - state->start + 1)) {
1609 if (state->state & bits) {
1610 /*
1611 * |--range with bits sets--|
1612 * |
1613 * start
1614 */
1615 start = state->end + 1;
1616 } else {
1617 /*
1618 * 'start' falls within a range that doesn't
1619 * have the bits set, so take its start as
1620 * the beginning of the desired range
1621 *
1622 * |--range with bits cleared----|
1623 * |
1624 * start
1625 */
1626 *start_ret = state->start;
1627 break;
1628 }
1629 } else {
1630 /*
1631 * |---prev range---|---hole/unset---|---node range---|
1632 * |
1633 * start
1634 *
1635 * or
1636 *
1637 * |---hole/unset--||--first node--|
1638 * 0 |
1639 * start
1640 */
1641 if (prev) {
1642 state = rb_entry(prev, struct extent_state,
1643 rb_node);
1644 *start_ret = state->end + 1;
1645 } else {
1646 *start_ret = 0;
1647 }
1648 break;
1649 }
1650 }
1651
1652 /*
1653 * Find the longest stretch from start until an entry which has the
1654 * bits set
1655 */
1656 while (1) {
1657 state = rb_entry(node, struct extent_state, rb_node);
1658 if (state->end >= start && !(state->state & bits)) {
1659 *end_ret = state->end;
1660 } else {
1661 *end_ret = state->start - 1;
1662 break;
1663 }
1664
1665 node = rb_next(node);
1666 if (!node)
1667 break;
1668 }
1669out:
1670 spin_unlock(&tree->lock);
1671}
1672
1673/*
1674 * find a contiguous range of bytes in the file marked as delalloc, not
1675 * more than 'max_bytes'. start and end are used to return the range,
1676 *
1677 * true is returned if we find something, false if nothing was in the tree
1678 */
1679static noinline bool find_delalloc_range(struct extent_io_tree *tree,
1680 u64 *start, u64 *end, u64 max_bytes,
1681 struct extent_state **cached_state)
1682{
1683 struct rb_node *node;
1684 struct extent_state *state;
1685 u64 cur_start = *start;
1686 bool found = false;
1687 u64 total_bytes = 0;
1688
1689 spin_lock(&tree->lock);
1690
1691 /*
1692 * this search will find all the extents that end after
1693 * our range starts.
1694 */
1695 node = tree_search(tree, cur_start);
1696 if (!node) {
1697 *end = (u64)-1;
1698 goto out;
1699 }
1700
1701 while (1) {
1702 state = rb_entry(node, struct extent_state, rb_node);
1703 if (found && (state->start != cur_start ||
1704 (state->state & EXTENT_BOUNDARY))) {
1705 goto out;
1706 }
1707 if (!(state->state & EXTENT_DELALLOC)) {
1708 if (!found)
1709 *end = state->end;
1710 goto out;
1711 }
1712 if (!found) {
1713 *start = state->start;
1714 *cached_state = state;
1715 refcount_inc(&state->refs);
1716 }
1717 found = true;
1718 *end = state->end;
1719 cur_start = state->end + 1;
1720 node = rb_next(node);
1721 total_bytes += state->end - state->start + 1;
1722 if (total_bytes >= max_bytes)
1723 break;
1724 if (!node)
1725 break;
1726 }
1727out:
1728 spin_unlock(&tree->lock);
1729 return found;
1730}
1731
1732static int __process_pages_contig(struct address_space *mapping,
1733 struct page *locked_page,
1734 pgoff_t start_index, pgoff_t end_index,
1735 unsigned long page_ops, pgoff_t *index_ret);
1736
1737static noinline void __unlock_for_delalloc(struct inode *inode,
1738 struct page *locked_page,
1739 u64 start, u64 end)
1740{
1741 unsigned long index = start >> PAGE_SHIFT;
1742 unsigned long end_index = end >> PAGE_SHIFT;
1743
1744 ASSERT(locked_page);
1745 if (index == locked_page->index && end_index == index)
1746 return;
1747
1748 __process_pages_contig(inode->i_mapping, locked_page, index, end_index,
1749 PAGE_UNLOCK, NULL);
1750}
1751
1752static noinline int lock_delalloc_pages(struct inode *inode,
1753 struct page *locked_page,
1754 u64 delalloc_start,
1755 u64 delalloc_end)
1756{
1757 unsigned long index = delalloc_start >> PAGE_SHIFT;
1758 unsigned long index_ret = index;
1759 unsigned long end_index = delalloc_end >> PAGE_SHIFT;
1760 int ret;
1761
1762 ASSERT(locked_page);
1763 if (index == locked_page->index && index == end_index)
1764 return 0;
1765
1766 ret = __process_pages_contig(inode->i_mapping, locked_page, index,
1767 end_index, PAGE_LOCK, &index_ret);
1768 if (ret == -EAGAIN)
1769 __unlock_for_delalloc(inode, locked_page, delalloc_start,
1770 (u64)index_ret << PAGE_SHIFT);
1771 return ret;
1772}
1773
1774/*
1775 * Find and lock a contiguous range of bytes in the file marked as delalloc, no
1776 * more than @max_bytes. @Start and @end are used to return the range,
1777 *
1778 * Return: true if we find something
1779 * false if nothing was in the tree
1780 */
1781EXPORT_FOR_TESTS
1782noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
1783 struct page *locked_page, u64 *start,
1784 u64 *end)
1785{
1786 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
1787 u64 max_bytes = BTRFS_MAX_EXTENT_SIZE;
1788 u64 delalloc_start;
1789 u64 delalloc_end;
1790 bool found;
1791 struct extent_state *cached_state = NULL;
1792 int ret;
1793 int loops = 0;
1794
1795again:
1796 /* step one, find a bunch of delalloc bytes starting at start */
1797 delalloc_start = *start;
1798 delalloc_end = 0;
1799 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1800 max_bytes, &cached_state);
1801 if (!found || delalloc_end <= *start) {
1802 *start = delalloc_start;
1803 *end = delalloc_end;
1804 free_extent_state(cached_state);
1805 return false;
1806 }
1807
1808 /*
1809 * start comes from the offset of locked_page. We have to lock
1810 * pages in order, so we can't process delalloc bytes before
1811 * locked_page
1812 */
1813 if (delalloc_start < *start)
1814 delalloc_start = *start;
1815
1816 /*
1817 * make sure to limit the number of pages we try to lock down
1818 */
1819 if (delalloc_end + 1 - delalloc_start > max_bytes)
1820 delalloc_end = delalloc_start + max_bytes - 1;
1821
1822 /* step two, lock all the pages after the page that has start */
1823 ret = lock_delalloc_pages(inode, locked_page,
1824 delalloc_start, delalloc_end);
1825 ASSERT(!ret || ret == -EAGAIN);
1826 if (ret == -EAGAIN) {
1827 /* some of the pages are gone, lets avoid looping by
1828 * shortening the size of the delalloc range we're searching
1829 */
1830 free_extent_state(cached_state);
1831 cached_state = NULL;
1832 if (!loops) {
1833 max_bytes = PAGE_SIZE;
1834 loops = 1;
1835 goto again;
1836 } else {
1837 found = false;
1838 goto out_failed;
1839 }
1840 }
1841
1842 /* step three, lock the state bits for the whole range */
1843 lock_extent_bits(tree, delalloc_start, delalloc_end, &cached_state);
1844
1845 /* then test to make sure it is all still delalloc */
1846 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1847 EXTENT_DELALLOC, 1, cached_state);
1848 if (!ret) {
1849 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1850 &cached_state);
1851 __unlock_for_delalloc(inode, locked_page,
1852 delalloc_start, delalloc_end);
1853 cond_resched();
1854 goto again;
1855 }
1856 free_extent_state(cached_state);
1857 *start = delalloc_start;
1858 *end = delalloc_end;
1859out_failed:
1860 return found;
1861}
1862
1863static int __process_pages_contig(struct address_space *mapping,
1864 struct page *locked_page,
1865 pgoff_t start_index, pgoff_t end_index,
1866 unsigned long page_ops, pgoff_t *index_ret)
1867{
1868 unsigned long nr_pages = end_index - start_index + 1;
1869 unsigned long pages_locked = 0;
1870 pgoff_t index = start_index;
1871 struct page *pages[16];
1872 unsigned ret;
1873 int err = 0;
1874 int i;
1875
1876 if (page_ops & PAGE_LOCK) {
1877 ASSERT(page_ops == PAGE_LOCK);
1878 ASSERT(index_ret && *index_ret == start_index);
1879 }
1880
1881 if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
1882 mapping_set_error(mapping, -EIO);
1883
1884 while (nr_pages > 0) {
1885 ret = find_get_pages_contig(mapping, index,
1886 min_t(unsigned long,
1887 nr_pages, ARRAY_SIZE(pages)), pages);
1888 if (ret == 0) {
1889 /*
1890 * Only if we're going to lock these pages,
1891 * can we find nothing at @index.
1892 */
1893 ASSERT(page_ops & PAGE_LOCK);
1894 err = -EAGAIN;
1895 goto out;
1896 }
1897
1898 for (i = 0; i < ret; i++) {
1899 if (page_ops & PAGE_SET_PRIVATE2)
1900 SetPagePrivate2(pages[i]);
1901
1902 if (pages[i] == locked_page) {
1903 put_page(pages[i]);
1904 pages_locked++;
1905 continue;
1906 }
1907 if (page_ops & PAGE_CLEAR_DIRTY)
1908 clear_page_dirty_for_io(pages[i]);
1909 if (page_ops & PAGE_SET_WRITEBACK)
1910 set_page_writeback(pages[i]);
1911 if (page_ops & PAGE_SET_ERROR)
1912 SetPageError(pages[i]);
1913 if (page_ops & PAGE_END_WRITEBACK)
1914 end_page_writeback(pages[i]);
1915 if (page_ops & PAGE_UNLOCK)
1916 unlock_page(pages[i]);
1917 if (page_ops & PAGE_LOCK) {
1918 lock_page(pages[i]);
1919 if (!PageDirty(pages[i]) ||
1920 pages[i]->mapping != mapping) {
1921 unlock_page(pages[i]);
1922 put_page(pages[i]);
1923 err = -EAGAIN;
1924 goto out;
1925 }
1926 }
1927 put_page(pages[i]);
1928 pages_locked++;
1929 }
1930 nr_pages -= ret;
1931 index += ret;
1932 cond_resched();
1933 }
1934out:
1935 if (err && index_ret)
1936 *index_ret = start_index + pages_locked - 1;
1937 return err;
1938}
1939
1940void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
1941 struct page *locked_page,
1942 unsigned clear_bits,
1943 unsigned long page_ops)
1944{
1945 clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, clear_bits, 1, 0,
1946 NULL);
1947
1948 __process_pages_contig(inode->i_mapping, locked_page,
1949 start >> PAGE_SHIFT, end >> PAGE_SHIFT,
1950 page_ops, NULL);
1951}
1952
1953/*
1954 * count the number of bytes in the tree that have a given bit(s)
1955 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1956 * cached. The total number found is returned.
1957 */
1958u64 count_range_bits(struct extent_io_tree *tree,
1959 u64 *start, u64 search_end, u64 max_bytes,
1960 unsigned bits, int contig)
1961{
1962 struct rb_node *node;
1963 struct extent_state *state;
1964 u64 cur_start = *start;
1965 u64 total_bytes = 0;
1966 u64 last = 0;
1967 int found = 0;
1968
1969 if (WARN_ON(search_end <= cur_start))
1970 return 0;
1971
1972 spin_lock(&tree->lock);
1973 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1974 total_bytes = tree->dirty_bytes;
1975 goto out;
1976 }
1977 /*
1978 * this search will find all the extents that end after
1979 * our range starts.
1980 */
1981 node = tree_search(tree, cur_start);
1982 if (!node)
1983 goto out;
1984
1985 while (1) {
1986 state = rb_entry(node, struct extent_state, rb_node);
1987 if (state->start > search_end)
1988 break;
1989 if (contig && found && state->start > last + 1)
1990 break;
1991 if (state->end >= cur_start && (state->state & bits) == bits) {
1992 total_bytes += min(search_end, state->end) + 1 -
1993 max(cur_start, state->start);
1994 if (total_bytes >= max_bytes)
1995 break;
1996 if (!found) {
1997 *start = max(cur_start, state->start);
1998 found = 1;
1999 }
2000 last = state->end;
2001 } else if (contig && found) {
2002 break;
2003 }
2004 node = rb_next(node);
2005 if (!node)
2006 break;
2007 }
2008out:
2009 spin_unlock(&tree->lock);
2010 return total_bytes;
2011}
2012
2013/*
2014 * set the private field for a given byte offset in the tree. If there isn't
2015 * an extent_state there already, this does nothing.
2016 */
2017static noinline int set_state_failrec(struct extent_io_tree *tree, u64 start,
2018 struct io_failure_record *failrec)
2019{
2020 struct rb_node *node;
2021 struct extent_state *state;
2022 int ret = 0;
2023
2024 spin_lock(&tree->lock);
2025 /*
2026 * this search will find all the extents that end after
2027 * our range starts.
2028 */
2029 node = tree_search(tree, start);
2030 if (!node) {
2031 ret = -ENOENT;
2032 goto out;
2033 }
2034 state = rb_entry(node, struct extent_state, rb_node);
2035 if (state->start != start) {
2036 ret = -ENOENT;
2037 goto out;
2038 }
2039 state->failrec = failrec;
2040out:
2041 spin_unlock(&tree->lock);
2042 return ret;
2043}
2044
2045static noinline int get_state_failrec(struct extent_io_tree *tree, u64 start,
2046 struct io_failure_record **failrec)
2047{
2048 struct rb_node *node;
2049 struct extent_state *state;
2050 int ret = 0;
2051
2052 spin_lock(&tree->lock);
2053 /*
2054 * this search will find all the extents that end after
2055 * our range starts.
2056 */
2057 node = tree_search(tree, start);
2058 if (!node) {
2059 ret = -ENOENT;
2060 goto out;
2061 }
2062 state = rb_entry(node, struct extent_state, rb_node);
2063 if (state->start != start) {
2064 ret = -ENOENT;
2065 goto out;
2066 }
2067 *failrec = state->failrec;
2068out:
2069 spin_unlock(&tree->lock);
2070 return ret;
2071}
2072
2073/*
2074 * searches a range in the state tree for a given mask.
2075 * If 'filled' == 1, this returns 1 only if every extent in the tree
2076 * has the bits set. Otherwise, 1 is returned if any bit in the
2077 * range is found set.
2078 */
2079int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
2080 unsigned bits, int filled, struct extent_state *cached)
2081{
2082 struct extent_state *state = NULL;
2083 struct rb_node *node;
2084 int bitset = 0;
2085
2086 spin_lock(&tree->lock);
2087 if (cached && extent_state_in_tree(cached) && cached->start <= start &&
2088 cached->end > start)
2089 node = &cached->rb_node;
2090 else
2091 node = tree_search(tree, start);
2092 while (node && start <= end) {
2093 state = rb_entry(node, struct extent_state, rb_node);
2094
2095 if (filled && state->start > start) {
2096 bitset = 0;
2097 break;
2098 }
2099
2100 if (state->start > end)
2101 break;
2102
2103 if (state->state & bits) {
2104 bitset = 1;
2105 if (!filled)
2106 break;
2107 } else if (filled) {
2108 bitset = 0;
2109 break;
2110 }
2111
2112 if (state->end == (u64)-1)
2113 break;
2114
2115 start = state->end + 1;
2116 if (start > end)
2117 break;
2118 node = rb_next(node);
2119 if (!node) {
2120 if (filled)
2121 bitset = 0;
2122 break;
2123 }
2124 }
2125 spin_unlock(&tree->lock);
2126 return bitset;
2127}
2128
2129/*
2130 * helper function to set a given page up to date if all the
2131 * extents in the tree for that page are up to date
2132 */
2133static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
2134{
2135 u64 start = page_offset(page);
2136 u64 end = start + PAGE_SIZE - 1;
2137 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
2138 SetPageUptodate(page);
2139}
2140
2141int free_io_failure(struct extent_io_tree *failure_tree,
2142 struct extent_io_tree *io_tree,
2143 struct io_failure_record *rec)
2144{
2145 int ret;
2146 int err = 0;
2147
2148 set_state_failrec(failure_tree, rec->start, NULL);
2149 ret = clear_extent_bits(failure_tree, rec->start,
2150 rec->start + rec->len - 1,
2151 EXTENT_LOCKED | EXTENT_DIRTY);
2152 if (ret)
2153 err = ret;
2154
2155 ret = clear_extent_bits(io_tree, rec->start,
2156 rec->start + rec->len - 1,
2157 EXTENT_DAMAGED);
2158 if (ret && !err)
2159 err = ret;
2160
2161 kfree(rec);
2162 return err;
2163}
2164
2165/*
2166 * this bypasses the standard btrfs submit functions deliberately, as
2167 * the standard behavior is to write all copies in a raid setup. here we only
2168 * want to write the one bad copy. so we do the mapping for ourselves and issue
2169 * submit_bio directly.
2170 * to avoid any synchronization issues, wait for the data after writing, which
2171 * actually prevents the read that triggered the error from finishing.
2172 * currently, there can be no more than two copies of every data bit. thus,
2173 * exactly one rewrite is required.
2174 */
2175int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
2176 u64 length, u64 logical, struct page *page,
2177 unsigned int pg_offset, int mirror_num)
2178{
2179 struct bio *bio;
2180 struct btrfs_device *dev;
2181 u64 map_length = 0;
2182 u64 sector;
2183 struct btrfs_bio *bbio = NULL;
2184 int ret;
2185
2186 ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
2187 BUG_ON(!mirror_num);
2188
2189 bio = btrfs_io_bio_alloc(1);
2190 bio->bi_iter.bi_size = 0;
2191 map_length = length;
2192
2193 /*
2194 * Avoid races with device replace and make sure our bbio has devices
2195 * associated to its stripes that don't go away while we are doing the
2196 * read repair operation.
2197 */
2198 btrfs_bio_counter_inc_blocked(fs_info);
2199 if (btrfs_is_parity_mirror(fs_info, logical, length)) {
2200 /*
2201 * Note that we don't use BTRFS_MAP_WRITE because it's supposed
2202 * to update all raid stripes, but here we just want to correct
2203 * bad stripe, thus BTRFS_MAP_READ is abused to only get the bad
2204 * stripe's dev and sector.
2205 */
2206 ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
2207 &map_length, &bbio, 0);
2208 if (ret) {
2209 btrfs_bio_counter_dec(fs_info);
2210 bio_put(bio);
2211 return -EIO;
2212 }
2213 ASSERT(bbio->mirror_num == 1);
2214 } else {
2215 ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
2216 &map_length, &bbio, mirror_num);
2217 if (ret) {
2218 btrfs_bio_counter_dec(fs_info);
2219 bio_put(bio);
2220 return -EIO;
2221 }
2222 BUG_ON(mirror_num != bbio->mirror_num);
2223 }
2224
2225 sector = bbio->stripes[bbio->mirror_num - 1].physical >> 9;
2226 bio->bi_iter.bi_sector = sector;
2227 dev = bbio->stripes[bbio->mirror_num - 1].dev;
2228 btrfs_put_bbio(bbio);
2229 if (!dev || !dev->bdev ||
2230 !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
2231 btrfs_bio_counter_dec(fs_info);
2232 bio_put(bio);
2233 return -EIO;
2234 }
2235 bio_set_dev(bio, dev->bdev);
2236 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
2237 bio_add_page(bio, page, length, pg_offset);
2238
2239 if (btrfsic_submit_bio_wait(bio)) {
2240 /* try to remap that extent elsewhere? */
2241 btrfs_bio_counter_dec(fs_info);
2242 bio_put(bio);
2243 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2244 return -EIO;
2245 }
2246
2247 btrfs_info_rl_in_rcu(fs_info,
2248 "read error corrected: ino %llu off %llu (dev %s sector %llu)",
2249 ino, start,
2250 rcu_str_deref(dev->name), sector);
2251 btrfs_bio_counter_dec(fs_info);
2252 bio_put(bio);
2253 return 0;
2254}
2255
2256int btrfs_repair_eb_io_failure(struct extent_buffer *eb, int mirror_num)
2257{
2258 struct btrfs_fs_info *fs_info = eb->fs_info;
2259 u64 start = eb->start;
2260 int i, num_pages = num_extent_pages(eb);
2261 int ret = 0;
2262
2263 if (sb_rdonly(fs_info->sb))
2264 return -EROFS;
2265
2266 for (i = 0; i < num_pages; i++) {
2267 struct page *p = eb->pages[i];
2268
2269 ret = repair_io_failure(fs_info, 0, start, PAGE_SIZE, start, p,
2270 start - page_offset(p), mirror_num);
2271 if (ret)
2272 break;
2273 start += PAGE_SIZE;
2274 }
2275
2276 return ret;
2277}
2278
2279/*
2280 * each time an IO finishes, we do a fast check in the IO failure tree
2281 * to see if we need to process or clean up an io_failure_record
2282 */
2283int clean_io_failure(struct btrfs_fs_info *fs_info,
2284 struct extent_io_tree *failure_tree,
2285 struct extent_io_tree *io_tree, u64 start,
2286 struct page *page, u64 ino, unsigned int pg_offset)
2287{
2288 u64 private;
2289 struct io_failure_record *failrec;
2290 struct extent_state *state;
2291 int num_copies;
2292 int ret;
2293
2294 private = 0;
2295 ret = count_range_bits(failure_tree, &private, (u64)-1, 1,
2296 EXTENT_DIRTY, 0);
2297 if (!ret)
2298 return 0;
2299
2300 ret = get_state_failrec(failure_tree, start, &failrec);
2301 if (ret)
2302 return 0;
2303
2304 BUG_ON(!failrec->this_mirror);
2305
2306 if (failrec->in_validation) {
2307 /* there was no real error, just free the record */
2308 btrfs_debug(fs_info,
2309 "clean_io_failure: freeing dummy error at %llu",
2310 failrec->start);
2311 goto out;
2312 }
2313 if (sb_rdonly(fs_info->sb))
2314 goto out;
2315
2316 spin_lock(&io_tree->lock);
2317 state = find_first_extent_bit_state(io_tree,
2318 failrec->start,
2319 EXTENT_LOCKED);
2320 spin_unlock(&io_tree->lock);
2321
2322 if (state && state->start <= failrec->start &&
2323 state->end >= failrec->start + failrec->len - 1) {
2324 num_copies = btrfs_num_copies(fs_info, failrec->logical,
2325 failrec->len);
2326 if (num_copies > 1) {
2327 repair_io_failure(fs_info, ino, start, failrec->len,
2328 failrec->logical, page, pg_offset,
2329 failrec->failed_mirror);
2330 }
2331 }
2332
2333out:
2334 free_io_failure(failure_tree, io_tree, failrec);
2335
2336 return 0;
2337}
2338
2339/*
2340 * Can be called when
2341 * - hold extent lock
2342 * - under ordered extent
2343 * - the inode is freeing
2344 */
2345void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start, u64 end)
2346{
2347 struct extent_io_tree *failure_tree = &inode->io_failure_tree;
2348 struct io_failure_record *failrec;
2349 struct extent_state *state, *next;
2350
2351 if (RB_EMPTY_ROOT(&failure_tree->state))
2352 return;
2353
2354 spin_lock(&failure_tree->lock);
2355 state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
2356 while (state) {
2357 if (state->start > end)
2358 break;
2359
2360 ASSERT(state->end <= end);
2361
2362 next = next_state(state);
2363
2364 failrec = state->failrec;
2365 free_extent_state(state);
2366 kfree(failrec);
2367
2368 state = next;
2369 }
2370 spin_unlock(&failure_tree->lock);
2371}
2372
2373int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
2374 struct io_failure_record **failrec_ret)
2375{
2376 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2377 struct io_failure_record *failrec;
2378 struct extent_map *em;
2379 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2380 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2381 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2382 int ret;
2383 u64 logical;
2384
2385 ret = get_state_failrec(failure_tree, start, &failrec);
2386 if (ret) {
2387 failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
2388 if (!failrec)
2389 return -ENOMEM;
2390
2391 failrec->start = start;
2392 failrec->len = end - start + 1;
2393 failrec->this_mirror = 0;
2394 failrec->bio_flags = 0;
2395 failrec->in_validation = 0;
2396
2397 read_lock(&em_tree->lock);
2398 em = lookup_extent_mapping(em_tree, start, failrec->len);
2399 if (!em) {
2400 read_unlock(&em_tree->lock);
2401 kfree(failrec);
2402 return -EIO;
2403 }
2404
2405 if (em->start > start || em->start + em->len <= start) {
2406 free_extent_map(em);
2407 em = NULL;
2408 }
2409 read_unlock(&em_tree->lock);
2410 if (!em) {
2411 kfree(failrec);
2412 return -EIO;
2413 }
2414
2415 logical = start - em->start;
2416 logical = em->block_start + logical;
2417 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2418 logical = em->block_start;
2419 failrec->bio_flags = EXTENT_BIO_COMPRESSED;
2420 extent_set_compress_type(&failrec->bio_flags,
2421 em->compress_type);
2422 }
2423
2424 btrfs_debug(fs_info,
2425 "Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu",
2426 logical, start, failrec->len);
2427
2428 failrec->logical = logical;
2429 free_extent_map(em);
2430
2431 /* set the bits in the private failure tree */
2432 ret = set_extent_bits(failure_tree, start, end,
2433 EXTENT_LOCKED | EXTENT_DIRTY);
2434 if (ret >= 0)
2435 ret = set_state_failrec(failure_tree, start, failrec);
2436 /* set the bits in the inode's tree */
2437 if (ret >= 0)
2438 ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED);
2439 if (ret < 0) {
2440 kfree(failrec);
2441 return ret;
2442 }
2443 } else {
2444 btrfs_debug(fs_info,
2445 "Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d",
2446 failrec->logical, failrec->start, failrec->len,
2447 failrec->in_validation);
2448 /*
2449 * when data can be on disk more than twice, add to failrec here
2450 * (e.g. with a list for failed_mirror) to make
2451 * clean_io_failure() clean all those errors at once.
2452 */
2453 }
2454
2455 *failrec_ret = failrec;
2456
2457 return 0;
2458}
2459
2460bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages,
2461 struct io_failure_record *failrec, int failed_mirror)
2462{
2463 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2464 int num_copies;
2465
2466 num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
2467 if (num_copies == 1) {
2468 /*
2469 * we only have a single copy of the data, so don't bother with
2470 * all the retry and error correction code that follows. no
2471 * matter what the error is, it is very likely to persist.
2472 */
2473 btrfs_debug(fs_info,
2474 "Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
2475 num_copies, failrec->this_mirror, failed_mirror);
2476 return false;
2477 }
2478
2479 /*
2480 * there are two premises:
2481 * a) deliver good data to the caller
2482 * b) correct the bad sectors on disk
2483 */
2484 if (failed_bio_pages > 1) {
2485 /*
2486 * to fulfill b), we need to know the exact failing sectors, as
2487 * we don't want to rewrite any more than the failed ones. thus,
2488 * we need separate read requests for the failed bio
2489 *
2490 * if the following BUG_ON triggers, our validation request got
2491 * merged. we need separate requests for our algorithm to work.
2492 */
2493 BUG_ON(failrec->in_validation);
2494 failrec->in_validation = 1;
2495 failrec->this_mirror = failed_mirror;
2496 } else {
2497 /*
2498 * we're ready to fulfill a) and b) alongside. get a good copy
2499 * of the failed sector and if we succeed, we have setup
2500 * everything for repair_io_failure to do the rest for us.
2501 */
2502 if (failrec->in_validation) {
2503 BUG_ON(failrec->this_mirror != failed_mirror);
2504 failrec->in_validation = 0;
2505 failrec->this_mirror = 0;
2506 }
2507 failrec->failed_mirror = failed_mirror;
2508 failrec->this_mirror++;
2509 if (failrec->this_mirror == failed_mirror)
2510 failrec->this_mirror++;
2511 }
2512
2513 if (failrec->this_mirror > num_copies) {
2514 btrfs_debug(fs_info,
2515 "Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
2516 num_copies, failrec->this_mirror, failed_mirror);
2517 return false;
2518 }
2519
2520 return true;
2521}
2522
2523
2524struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
2525 struct io_failure_record *failrec,
2526 struct page *page, int pg_offset, int icsum,
2527 bio_end_io_t *endio_func, void *data)
2528{
2529 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2530 struct bio *bio;
2531 struct btrfs_io_bio *btrfs_failed_bio;
2532 struct btrfs_io_bio *btrfs_bio;
2533
2534 bio = btrfs_io_bio_alloc(1);
2535 bio->bi_end_io = endio_func;
2536 bio->bi_iter.bi_sector = failrec->logical >> 9;
2537 bio_set_dev(bio, fs_info->fs_devices->latest_bdev);
2538 bio->bi_iter.bi_size = 0;
2539 bio->bi_private = data;
2540
2541 btrfs_failed_bio = btrfs_io_bio(failed_bio);
2542 if (btrfs_failed_bio->csum) {
2543 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
2544
2545 btrfs_bio = btrfs_io_bio(bio);
2546 btrfs_bio->csum = btrfs_bio->csum_inline;
2547 icsum *= csum_size;
2548 memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
2549 csum_size);
2550 }
2551
2552 bio_add_page(bio, page, failrec->len, pg_offset);
2553
2554 return bio;
2555}
2556
2557/*
2558 * This is a generic handler for readpage errors. If other copies exist, read
2559 * those and write back good data to the failed position. Does not investigate
2560 * in remapping the failed extent elsewhere, hoping the device will be smart
2561 * enough to do this as needed
2562 */
2563static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
2564 struct page *page, u64 start, u64 end,
2565 int failed_mirror)
2566{
2567 struct io_failure_record *failrec;
2568 struct inode *inode = page->mapping->host;
2569 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
2570 struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
2571 struct bio *bio;
2572 int read_mode = 0;
2573 blk_status_t status;
2574 int ret;
2575 unsigned failed_bio_pages = failed_bio->bi_iter.bi_size >> PAGE_SHIFT;
2576
2577 BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
2578
2579 ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
2580 if (ret)
2581 return ret;
2582
2583 if (!btrfs_check_repairable(inode, failed_bio_pages, failrec,
2584 failed_mirror)) {
2585 free_io_failure(failure_tree, tree, failrec);
2586 return -EIO;
2587 }
2588
2589 if (failed_bio_pages > 1)
2590 read_mode |= REQ_FAILFAST_DEV;
2591
2592 phy_offset >>= inode->i_sb->s_blocksize_bits;
2593 bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
2594 start - page_offset(page),
2595 (int)phy_offset, failed_bio->bi_end_io,
2596 NULL);
2597 bio->bi_opf = REQ_OP_READ | read_mode;
2598
2599 btrfs_debug(btrfs_sb(inode->i_sb),
2600 "Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d",
2601 read_mode, failrec->this_mirror, failrec->in_validation);
2602
2603 status = tree->ops->submit_bio_hook(tree->private_data, bio, failrec->this_mirror,
2604 failrec->bio_flags);
2605 if (status) {
2606 free_io_failure(failure_tree, tree, failrec);
2607 bio_put(bio);
2608 ret = blk_status_to_errno(status);
2609 }
2610
2611 return ret;
2612}
2613
2614/* lots and lots of room for performance fixes in the end_bio funcs */
2615
2616void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
2617{
2618 int uptodate = (err == 0);
2619 int ret = 0;
2620
2621 btrfs_writepage_endio_finish_ordered(page, start, end, uptodate);
2622
2623 if (!uptodate) {
2624 ClearPageUptodate(page);
2625 SetPageError(page);
2626 ret = err < 0 ? err : -EIO;
2627 mapping_set_error(page->mapping, ret);
2628 }
2629}
2630
2631/*
2632 * after a writepage IO is done, we need to:
2633 * clear the uptodate bits on error
2634 * clear the writeback bits in the extent tree for this IO
2635 * end_page_writeback if the page has no more pending IO
2636 *
2637 * Scheduling is not allowed, so the extent state tree is expected
2638 * to have one and only one object corresponding to this IO.
2639 */
2640static void end_bio_extent_writepage(struct bio *bio)
2641{
2642 int error = blk_status_to_errno(bio->bi_status);
2643 struct bio_vec *bvec;
2644 u64 start;
2645 u64 end;
2646 struct bvec_iter_all iter_all;
2647
2648 ASSERT(!bio_flagged(bio, BIO_CLONED));
2649 bio_for_each_segment_all(bvec, bio, iter_all) {
2650 struct page *page = bvec->bv_page;
2651 struct inode *inode = page->mapping->host;
2652 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2653
2654 /* We always issue full-page reads, but if some block
2655 * in a page fails to read, blk_update_request() will
2656 * advance bv_offset and adjust bv_len to compensate.
2657 * Print a warning for nonzero offsets, and an error
2658 * if they don't add up to a full page. */
2659 if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2660 if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2661 btrfs_err(fs_info,
2662 "partial page write in btrfs with offset %u and length %u",
2663 bvec->bv_offset, bvec->bv_len);
2664 else
2665 btrfs_info(fs_info,
2666 "incomplete page write in btrfs with offset %u and length %u",
2667 bvec->bv_offset, bvec->bv_len);
2668 }
2669
2670 start = page_offset(page);
2671 end = start + bvec->bv_offset + bvec->bv_len - 1;
2672
2673 end_extent_writepage(page, error, start, end);
2674 end_page_writeback(page);
2675 }
2676
2677 bio_put(bio);
2678}
2679
2680static void
2681endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
2682 int uptodate)
2683{
2684 struct extent_state *cached = NULL;
2685 u64 end = start + len - 1;
2686
2687 if (uptodate && tree->track_uptodate)
2688 set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
2689 unlock_extent_cached_atomic(tree, start, end, &cached);
2690}
2691
2692/*
2693 * after a readpage IO is done, we need to:
2694 * clear the uptodate bits on error
2695 * set the uptodate bits if things worked
2696 * set the page up to date if all extents in the tree are uptodate
2697 * clear the lock bit in the extent tree
2698 * unlock the page if there are no other extents locked for it
2699 *
2700 * Scheduling is not allowed, so the extent state tree is expected
2701 * to have one and only one object corresponding to this IO.
2702 */
2703static void end_bio_extent_readpage(struct bio *bio)
2704{
2705 struct bio_vec *bvec;
2706 int uptodate = !bio->bi_status;
2707 struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2708 struct extent_io_tree *tree, *failure_tree;
2709 u64 offset = 0;
2710 u64 start;
2711 u64 end;
2712 u64 len;
2713 u64 extent_start = 0;
2714 u64 extent_len = 0;
2715 int mirror;
2716 int ret;
2717 struct bvec_iter_all iter_all;
2718
2719 ASSERT(!bio_flagged(bio, BIO_CLONED));
2720 bio_for_each_segment_all(bvec, bio, iter_all) {
2721 struct page *page = bvec->bv_page;
2722 struct inode *inode = page->mapping->host;
2723 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2724 bool data_inode = btrfs_ino(BTRFS_I(inode))
2725 != BTRFS_BTREE_INODE_OBJECTID;
2726
2727 btrfs_debug(fs_info,
2728 "end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
2729 (u64)bio->bi_iter.bi_sector, bio->bi_status,
2730 io_bio->mirror_num);
2731 tree = &BTRFS_I(inode)->io_tree;
2732 failure_tree = &BTRFS_I(inode)->io_failure_tree;
2733
2734 /* We always issue full-page reads, but if some block
2735 * in a page fails to read, blk_update_request() will
2736 * advance bv_offset and adjust bv_len to compensate.
2737 * Print a warning for nonzero offsets, and an error
2738 * if they don't add up to a full page. */
2739 if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
2740 if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
2741 btrfs_err(fs_info,
2742 "partial page read in btrfs with offset %u and length %u",
2743 bvec->bv_offset, bvec->bv_len);
2744 else
2745 btrfs_info(fs_info,
2746 "incomplete page read in btrfs with offset %u and length %u",
2747 bvec->bv_offset, bvec->bv_len);
2748 }
2749
2750 start = page_offset(page);
2751 end = start + bvec->bv_offset + bvec->bv_len - 1;
2752 len = bvec->bv_len;
2753
2754 mirror = io_bio->mirror_num;
2755 if (likely(uptodate)) {
2756 ret = tree->ops->readpage_end_io_hook(io_bio, offset,
2757 page, start, end,
2758 mirror);
2759 if (ret)
2760 uptodate = 0;
2761 else
2762 clean_io_failure(BTRFS_I(inode)->root->fs_info,
2763 failure_tree, tree, start,
2764 page,
2765 btrfs_ino(BTRFS_I(inode)), 0);
2766 }
2767
2768 if (likely(uptodate))
2769 goto readpage_ok;
2770
2771 if (data_inode) {
2772
2773 /*
2774 * The generic bio_readpage_error handles errors the
2775 * following way: If possible, new read requests are
2776 * created and submitted and will end up in
2777 * end_bio_extent_readpage as well (if we're lucky,
2778 * not in the !uptodate case). In that case it returns
2779 * 0 and we just go on with the next page in our bio.
2780 * If it can't handle the error it will return -EIO and
2781 * we remain responsible for that page.
2782 */
2783 ret = bio_readpage_error(bio, offset, page, start, end,
2784 mirror);
2785 if (ret == 0) {
2786 uptodate = !bio->bi_status;
2787 offset += len;
2788 continue;
2789 }
2790 } else {
2791 struct extent_buffer *eb;
2792
2793 eb = (struct extent_buffer *)page->private;
2794 set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
2795 eb->read_mirror = mirror;
2796 atomic_dec(&eb->io_pages);
2797 if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD,
2798 &eb->bflags))
2799 btree_readahead_hook(eb, -EIO);
2800 }
2801readpage_ok:
2802 if (likely(uptodate)) {
2803 loff_t i_size = i_size_read(inode);
2804 pgoff_t end_index = i_size >> PAGE_SHIFT;
2805 unsigned off;
2806
2807 /* Zero out the end if this page straddles i_size */
2808 off = offset_in_page(i_size);
2809 if (page->index == end_index && off)
2810 zero_user_segment(page, off, PAGE_SIZE);
2811 SetPageUptodate(page);
2812 } else {
2813 ClearPageUptodate(page);
2814 SetPageError(page);
2815 }
2816 unlock_page(page);
2817 offset += len;
2818
2819 if (unlikely(!uptodate)) {
2820 if (extent_len) {
2821 endio_readpage_release_extent(tree,
2822 extent_start,
2823 extent_len, 1);
2824 extent_start = 0;
2825 extent_len = 0;
2826 }
2827 endio_readpage_release_extent(tree, start,
2828 end - start + 1, 0);
2829 } else if (!extent_len) {
2830 extent_start = start;
2831 extent_len = end + 1 - start;
2832 } else if (extent_start + extent_len == start) {
2833 extent_len += end + 1 - start;
2834 } else {
2835 endio_readpage_release_extent(tree, extent_start,
2836 extent_len, uptodate);
2837 extent_start = start;
2838 extent_len = end + 1 - start;
2839 }
2840 }
2841
2842 if (extent_len)
2843 endio_readpage_release_extent(tree, extent_start, extent_len,
2844 uptodate);
2845 btrfs_io_bio_free_csum(io_bio);
2846 bio_put(bio);
2847}
2848
2849/*
2850 * Initialize the members up to but not including 'bio'. Use after allocating a
2851 * new bio by bio_alloc_bioset as it does not initialize the bytes outside of
2852 * 'bio' because use of __GFP_ZERO is not supported.
2853 */
2854static inline void btrfs_io_bio_init(struct btrfs_io_bio *btrfs_bio)
2855{
2856 memset(btrfs_bio, 0, offsetof(struct btrfs_io_bio, bio));
2857}
2858
2859/*
2860 * The following helpers allocate a bio. As it's backed by a bioset, it'll
2861 * never fail. We're returning a bio right now but you can call btrfs_io_bio
2862 * for the appropriate container_of magic
2863 */
2864struct bio *btrfs_bio_alloc(u64 first_byte)
2865{
2866 struct bio *bio;
2867
2868 bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, &btrfs_bioset);
2869 bio->bi_iter.bi_sector = first_byte >> 9;
2870 btrfs_io_bio_init(btrfs_io_bio(bio));
2871 return bio;
2872}
2873
2874struct bio *btrfs_bio_clone(struct bio *bio)
2875{
2876 struct btrfs_io_bio *btrfs_bio;
2877 struct bio *new;
2878
2879 /* Bio allocation backed by a bioset does not fail */
2880 new = bio_clone_fast(bio, GFP_NOFS, &btrfs_bioset);
2881 btrfs_bio = btrfs_io_bio(new);
2882 btrfs_io_bio_init(btrfs_bio);
2883 btrfs_bio->iter = bio->bi_iter;
2884 return new;
2885}
2886
2887struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs)
2888{
2889 struct bio *bio;
2890
2891 /* Bio allocation backed by a bioset does not fail */
2892 bio = bio_alloc_bioset(GFP_NOFS, nr_iovecs, &btrfs_bioset);
2893 btrfs_io_bio_init(btrfs_io_bio(bio));
2894 return bio;
2895}
2896
2897struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size)
2898{
2899 struct bio *bio;
2900 struct btrfs_io_bio *btrfs_bio;
2901
2902 /* this will never fail when it's backed by a bioset */
2903 bio = bio_clone_fast(orig, GFP_NOFS, &btrfs_bioset);
2904 ASSERT(bio);
2905
2906 btrfs_bio = btrfs_io_bio(bio);
2907 btrfs_io_bio_init(btrfs_bio);
2908
2909 bio_trim(bio, offset >> 9, size >> 9);
2910 btrfs_bio->iter = bio->bi_iter;
2911 return bio;
2912}
2913
2914/*
2915 * @opf: bio REQ_OP_* and REQ_* flags as one value
2916 * @tree: tree so we can call our merge_bio hook
2917 * @wbc: optional writeback control for io accounting
2918 * @page: page to add to the bio
2919 * @pg_offset: offset of the new bio or to check whether we are adding
2920 * a contiguous page to the previous one
2921 * @size: portion of page that we want to write
2922 * @offset: starting offset in the page
2923 * @bdev: attach newly created bios to this bdev
2924 * @bio_ret: must be valid pointer, newly allocated bio will be stored there
2925 * @end_io_func: end_io callback for new bio
2926 * @mirror_num: desired mirror to read/write
2927 * @prev_bio_flags: flags of previous bio to see if we can merge the current one
2928 * @bio_flags: flags of the current bio to see if we can merge them
2929 */
2930static int submit_extent_page(unsigned int opf, struct extent_io_tree *tree,
2931 struct writeback_control *wbc,
2932 struct page *page, u64 offset,
2933 size_t size, unsigned long pg_offset,
2934 struct block_device *bdev,
2935 struct bio **bio_ret,
2936 bio_end_io_t end_io_func,
2937 int mirror_num,
2938 unsigned long prev_bio_flags,
2939 unsigned long bio_flags,
2940 bool force_bio_submit)
2941{
2942 int ret = 0;
2943 struct bio *bio;
2944 size_t page_size = min_t(size_t, size, PAGE_SIZE);
2945 sector_t sector = offset >> 9;
2946
2947 ASSERT(bio_ret);
2948
2949 if (*bio_ret) {
2950 bool contig;
2951 bool can_merge = true;
2952
2953 bio = *bio_ret;
2954 if (prev_bio_flags & EXTENT_BIO_COMPRESSED)
2955 contig = bio->bi_iter.bi_sector == sector;
2956 else
2957 contig = bio_end_sector(bio) == sector;
2958
2959 ASSERT(tree->ops);
2960 if (btrfs_bio_fits_in_stripe(page, page_size, bio, bio_flags))
2961 can_merge = false;
2962
2963 if (prev_bio_flags != bio_flags || !contig || !can_merge ||
2964 force_bio_submit ||
2965 bio_add_page(bio, page, page_size, pg_offset) < page_size) {
2966 ret = submit_one_bio(bio, mirror_num, prev_bio_flags);
2967 if (ret < 0) {
2968 *bio_ret = NULL;
2969 return ret;
2970 }
2971 bio = NULL;
2972 } else {
2973 if (wbc)
2974 wbc_account_cgroup_owner(wbc, page, page_size);
2975 return 0;
2976 }
2977 }
2978
2979 bio = btrfs_bio_alloc(offset);
2980 bio_set_dev(bio, bdev);
2981 bio_add_page(bio, page, page_size, pg_offset);
2982 bio->bi_end_io = end_io_func;
2983 bio->bi_private = tree;
2984 bio->bi_write_hint = page->mapping->host->i_write_hint;
2985 bio->bi_opf = opf;
2986 if (wbc) {
2987 wbc_init_bio(wbc, bio);
2988 wbc_account_cgroup_owner(wbc, page, page_size);
2989 }
2990
2991 *bio_ret = bio;
2992
2993 return ret;
2994}
2995
2996static void attach_extent_buffer_page(struct extent_buffer *eb,
2997 struct page *page)
2998{
2999 if (!PagePrivate(page)) {
3000 SetPagePrivate(page);
3001 get_page(page);
3002 set_page_private(page, (unsigned long)eb);
3003 } else {
3004 WARN_ON(page->private != (unsigned long)eb);
3005 }
3006}
3007
3008void set_page_extent_mapped(struct page *page)
3009{
3010 if (!PagePrivate(page)) {
3011 SetPagePrivate(page);
3012 get_page(page);
3013 set_page_private(page, EXTENT_PAGE_PRIVATE);
3014 }
3015}
3016
3017static struct extent_map *
3018__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
3019 u64 start, u64 len, get_extent_t *get_extent,
3020 struct extent_map **em_cached)
3021{
3022 struct extent_map *em;
3023
3024 if (em_cached && *em_cached) {
3025 em = *em_cached;
3026 if (extent_map_in_tree(em) && start >= em->start &&
3027 start < extent_map_end(em)) {
3028 refcount_inc(&em->refs);
3029 return em;
3030 }
3031
3032 free_extent_map(em);
3033 *em_cached = NULL;
3034 }
3035
3036 em = get_extent(BTRFS_I(inode), page, pg_offset, start, len, 0);
3037 if (em_cached && !IS_ERR_OR_NULL(em)) {
3038 BUG_ON(*em_cached);
3039 refcount_inc(&em->refs);
3040 *em_cached = em;
3041 }
3042 return em;
3043}
3044/*
3045 * basic readpage implementation. Locked extent state structs are inserted
3046 * into the tree that are removed when the IO is done (by the end_io
3047 * handlers)
3048 * XXX JDM: This needs looking at to ensure proper page locking
3049 * return 0 on success, otherwise return error
3050 */
3051static int __do_readpage(struct extent_io_tree *tree,
3052 struct page *page,
3053 get_extent_t *get_extent,
3054 struct extent_map **em_cached,
3055 struct bio **bio, int mirror_num,
3056 unsigned long *bio_flags, unsigned int read_flags,
3057 u64 *prev_em_start)
3058{
3059 struct inode *inode = page->mapping->host;
3060 u64 start = page_offset(page);
3061 const u64 end = start + PAGE_SIZE - 1;
3062 u64 cur = start;
3063 u64 extent_offset;
3064 u64 last_byte = i_size_read(inode);
3065 u64 block_start;
3066 u64 cur_end;
3067 struct extent_map *em;
3068 struct block_device *bdev;
3069 int ret = 0;
3070 int nr = 0;
3071 size_t pg_offset = 0;
3072 size_t iosize;
3073 size_t disk_io_size;
3074 size_t blocksize = inode->i_sb->s_blocksize;
3075 unsigned long this_bio_flag = 0;
3076
3077 set_page_extent_mapped(page);
3078
3079 if (!PageUptodate(page)) {
3080 if (cleancache_get_page(page) == 0) {
3081 BUG_ON(blocksize != PAGE_SIZE);
3082 unlock_extent(tree, start, end);
3083 goto out;
3084 }
3085 }
3086
3087 if (page->index == last_byte >> PAGE_SHIFT) {
3088 char *userpage;
3089 size_t zero_offset = offset_in_page(last_byte);
3090
3091 if (zero_offset) {
3092 iosize = PAGE_SIZE - zero_offset;
3093 userpage = kmap_atomic(page);
3094 memset(userpage + zero_offset, 0, iosize);
3095 flush_dcache_page(page);
3096 kunmap_atomic(userpage);
3097 }
3098 }
3099 while (cur <= end) {
3100 bool force_bio_submit = false;
3101 u64 offset;
3102
3103 if (cur >= last_byte) {
3104 char *userpage;
3105 struct extent_state *cached = NULL;
3106
3107 iosize = PAGE_SIZE - pg_offset;
3108 userpage = kmap_atomic(page);
3109 memset(userpage + pg_offset, 0, iosize);
3110 flush_dcache_page(page);
3111 kunmap_atomic(userpage);
3112 set_extent_uptodate(tree, cur, cur + iosize - 1,
3113 &cached, GFP_NOFS);
3114 unlock_extent_cached(tree, cur,
3115 cur + iosize - 1, &cached);
3116 break;
3117 }
3118 em = __get_extent_map(inode, page, pg_offset, cur,
3119 end - cur + 1, get_extent, em_cached);
3120 if (IS_ERR_OR_NULL(em)) {
3121 SetPageError(page);
3122 unlock_extent(tree, cur, end);
3123 break;
3124 }
3125 extent_offset = cur - em->start;
3126 BUG_ON(extent_map_end(em) <= cur);
3127 BUG_ON(end < cur);
3128
3129 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
3130 this_bio_flag |= EXTENT_BIO_COMPRESSED;
3131 extent_set_compress_type(&this_bio_flag,
3132 em->compress_type);
3133 }
3134
3135 iosize = min(extent_map_end(em) - cur, end - cur + 1);
3136 cur_end = min(extent_map_end(em) - 1, end);
3137 iosize = ALIGN(iosize, blocksize);
3138 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
3139 disk_io_size = em->block_len;
3140 offset = em->block_start;
3141 } else {
3142 offset = em->block_start + extent_offset;
3143 disk_io_size = iosize;
3144 }
3145 bdev = em->bdev;
3146 block_start = em->block_start;
3147 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
3148 block_start = EXTENT_MAP_HOLE;
3149
3150 /*
3151 * If we have a file range that points to a compressed extent
3152 * and it's followed by a consecutive file range that points to
3153 * to the same compressed extent (possibly with a different
3154 * offset and/or length, so it either points to the whole extent
3155 * or only part of it), we must make sure we do not submit a
3156 * single bio to populate the pages for the 2 ranges because
3157 * this makes the compressed extent read zero out the pages
3158 * belonging to the 2nd range. Imagine the following scenario:
3159 *
3160 * File layout
3161 * [0 - 8K] [8K - 24K]
3162 * | |
3163 * | |
3164 * points to extent X, points to extent X,
3165 * offset 4K, length of 8K offset 0, length 16K
3166 *
3167 * [extent X, compressed length = 4K uncompressed length = 16K]
3168 *
3169 * If the bio to read the compressed extent covers both ranges,
3170 * it will decompress extent X into the pages belonging to the
3171 * first range and then it will stop, zeroing out the remaining
3172 * pages that belong to the other range that points to extent X.
3173 * So here we make sure we submit 2 bios, one for the first
3174 * range and another one for the third range. Both will target
3175 * the same physical extent from disk, but we can't currently
3176 * make the compressed bio endio callback populate the pages
3177 * for both ranges because each compressed bio is tightly
3178 * coupled with a single extent map, and each range can have
3179 * an extent map with a different offset value relative to the
3180 * uncompressed data of our extent and different lengths. This
3181 * is a corner case so we prioritize correctness over
3182 * non-optimal behavior (submitting 2 bios for the same extent).
3183 */
3184 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
3185 prev_em_start && *prev_em_start != (u64)-1 &&
3186 *prev_em_start != em->start)
3187 force_bio_submit = true;
3188
3189 if (prev_em_start)
3190 *prev_em_start = em->start;
3191
3192 free_extent_map(em);
3193 em = NULL;
3194
3195 /* we've found a hole, just zero and go on */
3196 if (block_start == EXTENT_MAP_HOLE) {
3197 char *userpage;
3198 struct extent_state *cached = NULL;
3199
3200 userpage = kmap_atomic(page);
3201 memset(userpage + pg_offset, 0, iosize);
3202 flush_dcache_page(page);
3203 kunmap_atomic(userpage);
3204
3205 set_extent_uptodate(tree, cur, cur + iosize - 1,
3206 &cached, GFP_NOFS);
3207 unlock_extent_cached(tree, cur,
3208 cur + iosize - 1, &cached);
3209 cur = cur + iosize;
3210 pg_offset += iosize;
3211 continue;
3212 }
3213 /* the get_extent function already copied into the page */
3214 if (test_range_bit(tree, cur, cur_end,
3215 EXTENT_UPTODATE, 1, NULL)) {
3216 check_page_uptodate(tree, page);
3217 unlock_extent(tree, cur, cur + iosize - 1);
3218 cur = cur + iosize;
3219 pg_offset += iosize;
3220 continue;
3221 }
3222 /* we have an inline extent but it didn't get marked up
3223 * to date. Error out
3224 */
3225 if (block_start == EXTENT_MAP_INLINE) {
3226 SetPageError(page);
3227 unlock_extent(tree, cur, cur + iosize - 1);
3228 cur = cur + iosize;
3229 pg_offset += iosize;
3230 continue;
3231 }
3232
3233 ret = submit_extent_page(REQ_OP_READ | read_flags, tree, NULL,
3234 page, offset, disk_io_size,
3235 pg_offset, bdev, bio,
3236 end_bio_extent_readpage, mirror_num,
3237 *bio_flags,
3238 this_bio_flag,
3239 force_bio_submit);
3240 if (!ret) {
3241 nr++;
3242 *bio_flags = this_bio_flag;
3243 } else {
3244 SetPageError(page);
3245 unlock_extent(tree, cur, cur + iosize - 1);
3246 goto out;
3247 }
3248 cur = cur + iosize;
3249 pg_offset += iosize;
3250 }
3251out:
3252 if (!nr) {
3253 if (!PageError(page))
3254 SetPageUptodate(page);
3255 unlock_page(page);
3256 }
3257 return ret;
3258}
3259
3260static inline void contiguous_readpages(struct extent_io_tree *tree,
3261 struct page *pages[], int nr_pages,
3262 u64 start, u64 end,
3263 struct extent_map **em_cached,
3264 struct bio **bio,
3265 unsigned long *bio_flags,
3266 u64 *prev_em_start)
3267{
3268 struct btrfs_inode *inode = BTRFS_I(pages[0]->mapping->host);
3269 int index;
3270
3271 btrfs_lock_and_flush_ordered_range(tree, inode, start, end, NULL);
3272
3273 for (index = 0; index < nr_pages; index++) {
3274 __do_readpage(tree, pages[index], btrfs_get_extent, em_cached,
3275 bio, 0, bio_flags, REQ_RAHEAD, prev_em_start);
3276 put_page(pages[index]);
3277 }
3278}
3279
3280static int __extent_read_full_page(struct extent_io_tree *tree,
3281 struct page *page,
3282 get_extent_t *get_extent,
3283 struct bio **bio, int mirror_num,
3284 unsigned long *bio_flags,
3285 unsigned int read_flags)
3286{
3287 struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
3288 u64 start = page_offset(page);
3289 u64 end = start + PAGE_SIZE - 1;
3290 int ret;
3291
3292 btrfs_lock_and_flush_ordered_range(tree, inode, start, end, NULL);
3293
3294 ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
3295 bio_flags, read_flags, NULL);
3296 return ret;
3297}
3298
3299int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3300 get_extent_t *get_extent, int mirror_num)
3301{
3302 struct bio *bio = NULL;
3303 unsigned long bio_flags = 0;
3304 int ret;
3305
3306 ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3307 &bio_flags, 0);
3308 if (bio)
3309 ret = submit_one_bio(bio, mirror_num, bio_flags);
3310 return ret;
3311}
3312
3313static void update_nr_written(struct writeback_control *wbc,
3314 unsigned long nr_written)
3315{
3316 wbc->nr_to_write -= nr_written;
3317}
3318
3319/*
3320 * helper for __extent_writepage, doing all of the delayed allocation setup.
3321 *
3322 * This returns 1 if btrfs_run_delalloc_range function did all the work required
3323 * to write the page (copy into inline extent). In this case the IO has
3324 * been started and the page is already unlocked.
3325 *
3326 * This returns 0 if all went well (page still locked)
3327 * This returns < 0 if there were errors (page still locked)
3328 */
3329static noinline_for_stack int writepage_delalloc(struct inode *inode,
3330 struct page *page, struct writeback_control *wbc,
3331 u64 delalloc_start, unsigned long *nr_written)
3332{
3333 u64 page_end = delalloc_start + PAGE_SIZE - 1;
3334 bool found;
3335 u64 delalloc_to_write = 0;
3336 u64 delalloc_end = 0;
3337 int ret;
3338 int page_started = 0;
3339
3340
3341 while (delalloc_end < page_end) {
3342 found = find_lock_delalloc_range(inode, page,
3343 &delalloc_start,
3344 &delalloc_end);
3345 if (!found) {
3346 delalloc_start = delalloc_end + 1;
3347 continue;
3348 }
3349 ret = btrfs_run_delalloc_range(inode, page, delalloc_start,
3350 delalloc_end, &page_started, nr_written, wbc);
3351 if (ret) {
3352 SetPageError(page);
3353 /*
3354 * btrfs_run_delalloc_range should return < 0 for error
3355 * but just in case, we use > 0 here meaning the IO is
3356 * started, so we don't want to return > 0 unless
3357 * things are going well.
3358 */
3359 ret = ret < 0 ? ret : -EIO;
3360 goto done;
3361 }
3362 /*
3363 * delalloc_end is already one less than the total length, so
3364 * we don't subtract one from PAGE_SIZE
3365 */
3366 delalloc_to_write += (delalloc_end - delalloc_start +
3367 PAGE_SIZE) >> PAGE_SHIFT;
3368 delalloc_start = delalloc_end + 1;
3369 }
3370 if (wbc->nr_to_write < delalloc_to_write) {
3371 int thresh = 8192;
3372
3373 if (delalloc_to_write < thresh * 2)
3374 thresh = delalloc_to_write;
3375 wbc->nr_to_write = min_t(u64, delalloc_to_write,
3376 thresh);
3377 }
3378
3379 /* did the fill delalloc function already unlock and start
3380 * the IO?
3381 */
3382 if (page_started) {
3383 /*
3384 * we've unlocked the page, so we can't update
3385 * the mapping's writeback index, just update
3386 * nr_to_write.
3387 */
3388 wbc->nr_to_write -= *nr_written;
3389 return 1;
3390 }
3391
3392 ret = 0;
3393
3394done:
3395 return ret;
3396}
3397
3398/*
3399 * helper for __extent_writepage. This calls the writepage start hooks,
3400 * and does the loop to map the page into extents and bios.
3401 *
3402 * We return 1 if the IO is started and the page is unlocked,
3403 * 0 if all went well (page still locked)
3404 * < 0 if there were errors (page still locked)
3405 */
3406static noinline_for_stack int __extent_writepage_io(struct inode *inode,
3407 struct page *page,
3408 struct writeback_control *wbc,
3409 struct extent_page_data *epd,
3410 loff_t i_size,
3411 unsigned long nr_written,
3412 unsigned int write_flags, int *nr_ret)
3413{
3414 struct extent_io_tree *tree = epd->tree;
3415 u64 start = page_offset(page);
3416 u64 page_end = start + PAGE_SIZE - 1;
3417 u64 end;
3418 u64 cur = start;
3419 u64 extent_offset;
3420 u64 block_start;
3421 u64 iosize;
3422 struct extent_map *em;
3423 struct block_device *bdev;
3424 size_t pg_offset = 0;
3425 size_t blocksize;
3426 int ret = 0;
3427 int nr = 0;
3428 bool compressed;
3429
3430 ret = btrfs_writepage_cow_fixup(page, start, page_end);
3431 if (ret) {
3432 /* Fixup worker will requeue */
3433 if (ret == -EBUSY)
3434 wbc->pages_skipped++;
3435 else
3436 redirty_page_for_writepage(wbc, page);
3437
3438 update_nr_written(wbc, nr_written);
3439 unlock_page(page);
3440 return 1;
3441 }
3442
3443 /*
3444 * we don't want to touch the inode after unlocking the page,
3445 * so we update the mapping writeback index now
3446 */
3447 update_nr_written(wbc, nr_written + 1);
3448
3449 end = page_end;
3450 if (i_size <= start) {
3451 btrfs_writepage_endio_finish_ordered(page, start, page_end, 1);
3452 goto done;
3453 }
3454
3455 blocksize = inode->i_sb->s_blocksize;
3456
3457 while (cur <= end) {
3458 u64 em_end;
3459 u64 offset;
3460
3461 if (cur >= i_size) {
3462 btrfs_writepage_endio_finish_ordered(page, cur,
3463 page_end, 1);
3464 break;
3465 }
3466 em = btrfs_get_extent(BTRFS_I(inode), page, pg_offset, cur,
3467 end - cur + 1, 1);
3468 if (IS_ERR_OR_NULL(em)) {
3469 SetPageError(page);
3470 ret = PTR_ERR_OR_ZERO(em);
3471 break;
3472 }
3473
3474 extent_offset = cur - em->start;
3475 em_end = extent_map_end(em);
3476 BUG_ON(em_end <= cur);
3477 BUG_ON(end < cur);
3478 iosize = min(em_end - cur, end - cur + 1);
3479 iosize = ALIGN(iosize, blocksize);
3480 offset = em->block_start + extent_offset;
3481 bdev = em->bdev;
3482 block_start = em->block_start;
3483 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3484 free_extent_map(em);
3485 em = NULL;
3486
3487 /*
3488 * compressed and inline extents are written through other
3489 * paths in the FS
3490 */
3491 if (compressed || block_start == EXTENT_MAP_HOLE ||
3492 block_start == EXTENT_MAP_INLINE) {
3493 /*
3494 * end_io notification does not happen here for
3495 * compressed extents
3496 */
3497 if (!compressed)
3498 btrfs_writepage_endio_finish_ordered(page, cur,
3499 cur + iosize - 1,
3500 1);
3501 else if (compressed) {
3502 /* we don't want to end_page_writeback on
3503 * a compressed extent. this happens
3504 * elsewhere
3505 */
3506 nr++;
3507 }
3508
3509 cur += iosize;
3510 pg_offset += iosize;
3511 continue;
3512 }
3513
3514 btrfs_set_range_writeback(tree, cur, cur + iosize - 1);
3515 if (!PageWriteback(page)) {
3516 btrfs_err(BTRFS_I(inode)->root->fs_info,
3517 "page %lu not writeback, cur %llu end %llu",
3518 page->index, cur, end);
3519 }
3520
3521 ret = submit_extent_page(REQ_OP_WRITE | write_flags, tree, wbc,
3522 page, offset, iosize, pg_offset,
3523 bdev, &epd->bio,
3524 end_bio_extent_writepage,
3525 0, 0, 0, false);
3526 if (ret) {
3527 SetPageError(page);
3528 if (PageWriteback(page))
3529 end_page_writeback(page);
3530 }
3531
3532 cur = cur + iosize;
3533 pg_offset += iosize;
3534 nr++;
3535 }
3536done:
3537 *nr_ret = nr;
3538 return ret;
3539}
3540
3541/*
3542 * the writepage semantics are similar to regular writepage. extent
3543 * records are inserted to lock ranges in the tree, and as dirty areas
3544 * are found, they are marked writeback. Then the lock bits are removed
3545 * and the end_io handler clears the writeback ranges
3546 *
3547 * Return 0 if everything goes well.
3548 * Return <0 for error.
3549 */
3550static int __extent_writepage(struct page *page, struct writeback_control *wbc,
3551 struct extent_page_data *epd)
3552{
3553 struct inode *inode = page->mapping->host;
3554 u64 start = page_offset(page);
3555 u64 page_end = start + PAGE_SIZE - 1;
3556 int ret;
3557 int nr = 0;
3558 size_t pg_offset = 0;
3559 loff_t i_size = i_size_read(inode);
3560 unsigned long end_index = i_size >> PAGE_SHIFT;
3561 unsigned int write_flags = 0;
3562 unsigned long nr_written = 0;
3563
3564 write_flags = wbc_to_write_flags(wbc);
3565
3566 trace___extent_writepage(page, inode, wbc);
3567
3568 WARN_ON(!PageLocked(page));
3569
3570 ClearPageError(page);
3571
3572 pg_offset = offset_in_page(i_size);
3573 if (page->index > end_index ||
3574 (page->index == end_index && !pg_offset)) {
3575 page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
3576 unlock_page(page);
3577 return 0;
3578 }
3579
3580 if (page->index == end_index) {
3581 char *userpage;
3582
3583 userpage = kmap_atomic(page);
3584 memset(userpage + pg_offset, 0,
3585 PAGE_SIZE - pg_offset);
3586 kunmap_atomic(userpage);
3587 flush_dcache_page(page);
3588 }
3589
3590 pg_offset = 0;
3591
3592 set_page_extent_mapped(page);
3593
3594 if (!epd->extent_locked) {
3595 ret = writepage_delalloc(inode, page, wbc, start, &nr_written);
3596 if (ret == 1)
3597 goto done_unlocked;
3598 if (ret)
3599 goto done;
3600 }
3601
3602 ret = __extent_writepage_io(inode, page, wbc, epd,
3603 i_size, nr_written, write_flags, &nr);
3604 if (ret == 1)
3605 goto done_unlocked;
3606
3607done:
3608 if (nr == 0) {
3609 /* make sure the mapping tag for page dirty gets cleared */
3610 set_page_writeback(page);
3611 end_page_writeback(page);
3612 }
3613 if (PageError(page)) {
3614 ret = ret < 0 ? ret : -EIO;
3615 end_extent_writepage(page, ret, start, page_end);
3616 }
3617 unlock_page(page);
3618 ASSERT(ret <= 0);
3619 return ret;
3620
3621done_unlocked:
3622 return 0;
3623}
3624
3625void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3626{
3627 wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
3628 TASK_UNINTERRUPTIBLE);
3629}
3630
3631static void end_extent_buffer_writeback(struct extent_buffer *eb)
3632{
3633 clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3634 smp_mb__after_atomic();
3635 wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
3636}
3637
3638/*
3639 * Lock eb pages and flush the bio if we can't the locks
3640 *
3641 * Return 0 if nothing went wrong
3642 * Return >0 is same as 0, except bio is not submitted
3643 * Return <0 if something went wrong, no page is locked
3644 */
3645static noinline_for_stack int lock_extent_buffer_for_io(struct extent_buffer *eb,
3646 struct extent_page_data *epd)
3647{
3648 struct btrfs_fs_info *fs_info = eb->fs_info;
3649 int i, num_pages, failed_page_nr;
3650 int flush = 0;
3651 int ret = 0;
3652
3653 if (!btrfs_try_tree_write_lock(eb)) {
3654 ret = flush_write_bio(epd);
3655 if (ret < 0)
3656 return ret;
3657 flush = 1;
3658 btrfs_tree_lock(eb);
3659 }
3660
3661 if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
3662 btrfs_tree_unlock(eb);
3663 if (!epd->sync_io)
3664 return 0;
3665 if (!flush) {
3666 ret = flush_write_bio(epd);
3667 if (ret < 0)
3668 return ret;
3669 flush = 1;
3670 }
3671 while (1) {
3672 wait_on_extent_buffer_writeback(eb);
3673 btrfs_tree_lock(eb);
3674 if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
3675 break;
3676 btrfs_tree_unlock(eb);
3677 }
3678 }
3679
3680 /*
3681 * We need to do this to prevent races in people who check if the eb is
3682 * under IO since we can end up having no IO bits set for a short period
3683 * of time.
3684 */
3685 spin_lock(&eb->refs_lock);
3686 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3687 set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3688 spin_unlock(&eb->refs_lock);
3689 btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3690 percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
3691 -eb->len,
3692 fs_info->dirty_metadata_batch);
3693 ret = 1;
3694 } else {
3695 spin_unlock(&eb->refs_lock);
3696 }
3697
3698 btrfs_tree_unlock(eb);
3699
3700 if (!ret)
3701 return ret;
3702
3703 num_pages = num_extent_pages(eb);
3704 for (i = 0; i < num_pages; i++) {
3705 struct page *p = eb->pages[i];
3706
3707 if (!trylock_page(p)) {
3708 if (!flush) {
3709 int err;
3710
3711 err = flush_write_bio(epd);
3712 if (err < 0) {
3713 ret = err;
3714 failed_page_nr = i;
3715 goto err_unlock;
3716 }
3717 flush = 1;
3718 }
3719 lock_page(p);
3720 }
3721 }
3722
3723 return ret;
3724err_unlock:
3725 /* Unlock already locked pages */
3726 for (i = 0; i < failed_page_nr; i++)
3727 unlock_page(eb->pages[i]);
3728 /*
3729 * Clear EXTENT_BUFFER_WRITEBACK and wake up anyone waiting on it.
3730 * Also set back EXTENT_BUFFER_DIRTY so future attempts to this eb can
3731 * be made and undo everything done before.
3732 */
3733 btrfs_tree_lock(eb);
3734 spin_lock(&eb->refs_lock);
3735 set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
3736 end_extent_buffer_writeback(eb);
3737 spin_unlock(&eb->refs_lock);
3738 percpu_counter_add_batch(&fs_info->dirty_metadata_bytes, eb->len,
3739 fs_info->dirty_metadata_batch);
3740 btrfs_clear_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3741 btrfs_tree_unlock(eb);
3742 return ret;
3743}
3744
3745static void set_btree_ioerr(struct page *page)
3746{
3747 struct extent_buffer *eb = (struct extent_buffer *)page->private;
3748 struct btrfs_fs_info *fs_info;
3749
3750 SetPageError(page);
3751 if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
3752 return;
3753
3754 /*
3755 * If we error out, we should add back the dirty_metadata_bytes
3756 * to make it consistent.
3757 */
3758 fs_info = eb->fs_info;
3759 percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
3760 eb->len, fs_info->dirty_metadata_batch);
3761
3762 /*
3763 * If writeback for a btree extent that doesn't belong to a log tree
3764 * failed, increment the counter transaction->eb_write_errors.
3765 * We do this because while the transaction is running and before it's
3766 * committing (when we call filemap_fdata[write|wait]_range against
3767 * the btree inode), we might have
3768 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
3769 * returns an error or an error happens during writeback, when we're
3770 * committing the transaction we wouldn't know about it, since the pages
3771 * can be no longer dirty nor marked anymore for writeback (if a
3772 * subsequent modification to the extent buffer didn't happen before the
3773 * transaction commit), which makes filemap_fdata[write|wait]_range not
3774 * able to find the pages tagged with SetPageError at transaction
3775 * commit time. So if this happens we must abort the transaction,
3776 * otherwise we commit a super block with btree roots that point to
3777 * btree nodes/leafs whose content on disk is invalid - either garbage
3778 * or the content of some node/leaf from a past generation that got
3779 * cowed or deleted and is no longer valid.
3780 *
3781 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
3782 * not be enough - we need to distinguish between log tree extents vs
3783 * non-log tree extents, and the next filemap_fdatawait_range() call
3784 * will catch and clear such errors in the mapping - and that call might
3785 * be from a log sync and not from a transaction commit. Also, checking
3786 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
3787 * not done and would not be reliable - the eb might have been released
3788 * from memory and reading it back again means that flag would not be
3789 * set (since it's a runtime flag, not persisted on disk).
3790 *
3791 * Using the flags below in the btree inode also makes us achieve the
3792 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
3793 * writeback for all dirty pages and before filemap_fdatawait_range()
3794 * is called, the writeback for all dirty pages had already finished
3795 * with errors - because we were not using AS_EIO/AS_ENOSPC,
3796 * filemap_fdatawait_range() would return success, as it could not know
3797 * that writeback errors happened (the pages were no longer tagged for
3798 * writeback).
3799 */
3800 switch (eb->log_index) {
3801 case -1:
3802 set_bit(BTRFS_FS_BTREE_ERR, &eb->fs_info->flags);
3803 break;
3804 case 0:
3805 set_bit(BTRFS_FS_LOG1_ERR, &eb->fs_info->flags);
3806 break;
3807 case 1:
3808 set_bit(BTRFS_FS_LOG2_ERR, &eb->fs_info->flags);
3809 break;
3810 default:
3811 BUG(); /* unexpected, logic error */
3812 }
3813}
3814
3815static void end_bio_extent_buffer_writepage(struct bio *bio)
3816{
3817 struct bio_vec *bvec;
3818 struct extent_buffer *eb;
3819 int done;
3820 struct bvec_iter_all iter_all;
3821
3822 ASSERT(!bio_flagged(bio, BIO_CLONED));
3823 bio_for_each_segment_all(bvec, bio, iter_all) {
3824 struct page *page = bvec->bv_page;
3825
3826 eb = (struct extent_buffer *)page->private;
3827 BUG_ON(!eb);
3828 done = atomic_dec_and_test(&eb->io_pages);
3829
3830 if (bio->bi_status ||
3831 test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
3832 ClearPageUptodate(page);
3833 set_btree_ioerr(page);
3834 }
3835
3836 end_page_writeback(page);
3837
3838 if (!done)
3839 continue;
3840
3841 end_extent_buffer_writeback(eb);
3842 }
3843
3844 bio_put(bio);
3845}
3846
3847static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3848 struct writeback_control *wbc,
3849 struct extent_page_data *epd)
3850{
3851 struct btrfs_fs_info *fs_info = eb->fs_info;
3852 struct block_device *bdev = fs_info->fs_devices->latest_bdev;
3853 struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3854 u64 offset = eb->start;
3855 u32 nritems;
3856 int i, num_pages;
3857 unsigned long start, end;
3858 unsigned int write_flags = wbc_to_write_flags(wbc) | REQ_META;
3859 int ret = 0;
3860
3861 clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
3862 num_pages = num_extent_pages(eb);
3863 atomic_set(&eb->io_pages, num_pages);
3864
3865 /* set btree blocks beyond nritems with 0 to avoid stale content. */
3866 nritems = btrfs_header_nritems(eb);
3867 if (btrfs_header_level(eb) > 0) {
3868 end = btrfs_node_key_ptr_offset(nritems);
3869
3870 memzero_extent_buffer(eb, end, eb->len - end);
3871 } else {
3872 /*
3873 * leaf:
3874 * header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
3875 */
3876 start = btrfs_item_nr_offset(nritems);
3877 end = BTRFS_LEAF_DATA_OFFSET + leaf_data_end(eb);
3878 memzero_extent_buffer(eb, start, end - start);
3879 }
3880
3881 for (i = 0; i < num_pages; i++) {
3882 struct page *p = eb->pages[i];
3883
3884 clear_page_dirty_for_io(p);
3885 set_page_writeback(p);
3886 ret = submit_extent_page(REQ_OP_WRITE | write_flags, tree, wbc,
3887 p, offset, PAGE_SIZE, 0, bdev,
3888 &epd->bio,
3889 end_bio_extent_buffer_writepage,
3890 0, 0, 0, false);
3891 if (ret) {
3892 set_btree_ioerr(p);
3893 if (PageWriteback(p))
3894 end_page_writeback(p);
3895 if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
3896 end_extent_buffer_writeback(eb);
3897 ret = -EIO;
3898 break;
3899 }
3900 offset += PAGE_SIZE;
3901 update_nr_written(wbc, 1);
3902 unlock_page(p);
3903 }
3904
3905 if (unlikely(ret)) {
3906 for (; i < num_pages; i++) {
3907 struct page *p = eb->pages[i];
3908 clear_page_dirty_for_io(p);
3909 unlock_page(p);
3910 }
3911 }
3912
3913 return ret;
3914}
3915
3916int btree_write_cache_pages(struct address_space *mapping,
3917 struct writeback_control *wbc)
3918{
3919 struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
3920 struct extent_buffer *eb, *prev_eb = NULL;
3921 struct extent_page_data epd = {
3922 .bio = NULL,
3923 .tree = tree,
3924 .extent_locked = 0,
3925 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
3926 };
3927 int ret = 0;
3928 int done = 0;
3929 int nr_to_write_done = 0;
3930 struct pagevec pvec;
3931 int nr_pages;
3932 pgoff_t index;
3933 pgoff_t end; /* Inclusive */
3934 int scanned = 0;
3935 xa_mark_t tag;
3936
3937 pagevec_init(&pvec);
3938 if (wbc->range_cyclic) {
3939 index = mapping->writeback_index; /* Start from prev offset */
3940 end = -1;
3941 } else {
3942 index = wbc->range_start >> PAGE_SHIFT;
3943 end = wbc->range_end >> PAGE_SHIFT;
3944 scanned = 1;
3945 }
3946 if (wbc->sync_mode == WB_SYNC_ALL)
3947 tag = PAGECACHE_TAG_TOWRITE;
3948 else
3949 tag = PAGECACHE_TAG_DIRTY;
3950retry:
3951 if (wbc->sync_mode == WB_SYNC_ALL)
3952 tag_pages_for_writeback(mapping, index, end);
3953 while (!done && !nr_to_write_done && (index <= end) &&
3954 (nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
3955 tag))) {
3956 unsigned i;
3957
3958 scanned = 1;
3959 for (i = 0; i < nr_pages; i++) {
3960 struct page *page = pvec.pages[i];
3961
3962 if (!PagePrivate(page))
3963 continue;
3964
3965 spin_lock(&mapping->private_lock);
3966 if (!PagePrivate(page)) {
3967 spin_unlock(&mapping->private_lock);
3968 continue;
3969 }
3970
3971 eb = (struct extent_buffer *)page->private;
3972
3973 /*
3974 * Shouldn't happen and normally this would be a BUG_ON
3975 * but no sense in crashing the users box for something
3976 * we can survive anyway.
3977 */
3978 if (WARN_ON(!eb)) {
3979 spin_unlock(&mapping->private_lock);
3980 continue;
3981 }
3982
3983 if (eb == prev_eb) {
3984 spin_unlock(&mapping->private_lock);
3985 continue;
3986 }
3987
3988 ret = atomic_inc_not_zero(&eb->refs);
3989 spin_unlock(&mapping->private_lock);
3990 if (!ret)
3991 continue;
3992
3993 prev_eb = eb;
3994 ret = lock_extent_buffer_for_io(eb, &epd);
3995 if (!ret) {
3996 free_extent_buffer(eb);
3997 continue;
3998 } else if (ret < 0) {
3999 done = 1;
4000 free_extent_buffer(eb);
4001 break;
4002 }
4003
4004 ret = write_one_eb(eb, wbc, &epd);
4005 if (ret) {
4006 done = 1;
4007 free_extent_buffer(eb);
4008 break;
4009 }
4010 free_extent_buffer(eb);
4011
4012 /*
4013 * the filesystem may choose to bump up nr_to_write.
4014 * We have to make sure to honor the new nr_to_write
4015 * at any time
4016 */
4017 nr_to_write_done = wbc->nr_to_write <= 0;
4018 }
4019 pagevec_release(&pvec);
4020 cond_resched();
4021 }
4022 if (!scanned && !done) {
4023 /*
4024 * We hit the last page and there is more work to be done: wrap
4025 * back to the start of the file
4026 */
4027 scanned = 1;
4028 index = 0;
4029 goto retry;
4030 }
4031 ASSERT(ret <= 0);
4032 if (ret < 0) {
4033 end_write_bio(&epd, ret);
4034 return ret;
4035 }
4036 ret = flush_write_bio(&epd);
4037 return ret;
4038}
4039
4040/**
4041 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
4042 * @mapping: address space structure to write
4043 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
4044 * @data: data passed to __extent_writepage function
4045 *
4046 * If a page is already under I/O, write_cache_pages() skips it, even
4047 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
4048 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
4049 * and msync() need to guarantee that all the data which was dirty at the time
4050 * the call was made get new I/O started against them. If wbc->sync_mode is
4051 * WB_SYNC_ALL then we were called for data integrity and we must wait for
4052 * existing IO to complete.
4053 */
4054static int extent_write_cache_pages(struct address_space *mapping,
4055 struct writeback_control *wbc,
4056 struct extent_page_data *epd)
4057{
4058 struct inode *inode = mapping->host;
4059 int ret = 0;
4060 int done = 0;
4061 int nr_to_write_done = 0;
4062 struct pagevec pvec;
4063 int nr_pages;
4064 pgoff_t index;
4065 pgoff_t end; /* Inclusive */
4066 pgoff_t done_index;
4067 int range_whole = 0;
4068 int scanned = 0;
4069 xa_mark_t tag;
4070
4071 /*
4072 * We have to hold onto the inode so that ordered extents can do their
4073 * work when the IO finishes. The alternative to this is failing to add
4074 * an ordered extent if the igrab() fails there and that is a huge pain
4075 * to deal with, so instead just hold onto the inode throughout the
4076 * writepages operation. If it fails here we are freeing up the inode
4077 * anyway and we'd rather not waste our time writing out stuff that is
4078 * going to be truncated anyway.
4079 */
4080 if (!igrab(inode))
4081 return 0;
4082
4083 pagevec_init(&pvec);
4084 if (wbc->range_cyclic) {
4085 index = mapping->writeback_index; /* Start from prev offset */
4086 end = -1;
4087 } else {
4088 index = wbc->range_start >> PAGE_SHIFT;
4089 end = wbc->range_end >> PAGE_SHIFT;
4090 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
4091 range_whole = 1;
4092 scanned = 1;
4093 }
4094
4095 /*
4096 * We do the tagged writepage as long as the snapshot flush bit is set
4097 * and we are the first one who do the filemap_flush() on this inode.
4098 *
4099 * The nr_to_write == LONG_MAX is needed to make sure other flushers do
4100 * not race in and drop the bit.
4101 */
4102 if (range_whole && wbc->nr_to_write == LONG_MAX &&
4103 test_and_clear_bit(BTRFS_INODE_SNAPSHOT_FLUSH,
4104 &BTRFS_I(inode)->runtime_flags))
4105 wbc->tagged_writepages = 1;
4106
4107 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
4108 tag = PAGECACHE_TAG_TOWRITE;
4109 else
4110 tag = PAGECACHE_TAG_DIRTY;
4111retry:
4112 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
4113 tag_pages_for_writeback(mapping, index, end);
4114 done_index = index;
4115 while (!done && !nr_to_write_done && (index <= end) &&
4116 (nr_pages = pagevec_lookup_range_tag(&pvec, mapping,
4117 &index, end, tag))) {
4118 unsigned i;
4119
4120 scanned = 1;
4121 for (i = 0; i < nr_pages; i++) {
4122 struct page *page = pvec.pages[i];
4123
4124 done_index = page->index;
4125 /*
4126 * At this point we hold neither the i_pages lock nor
4127 * the page lock: the page may be truncated or
4128 * invalidated (changing page->mapping to NULL),
4129 * or even swizzled back from swapper_space to
4130 * tmpfs file mapping
4131 */
4132 if (!trylock_page(page)) {
4133 ret = flush_write_bio(epd);
4134 BUG_ON(ret < 0);
4135 lock_page(page);
4136 }
4137
4138 if (unlikely(page->mapping != mapping)) {
4139 unlock_page(page);
4140 continue;
4141 }
4142
4143 if (wbc->sync_mode != WB_SYNC_NONE) {
4144 if (PageWriteback(page)) {
4145 ret = flush_write_bio(epd);
4146 BUG_ON(ret < 0);
4147 }
4148 wait_on_page_writeback(page);
4149 }
4150
4151 if (PageWriteback(page) ||
4152 !clear_page_dirty_for_io(page)) {
4153 unlock_page(page);
4154 continue;
4155 }
4156
4157 ret = __extent_writepage(page, wbc, epd);
4158 if (ret < 0) {
4159 /*
4160 * done_index is set past this page,
4161 * so media errors will not choke
4162 * background writeout for the entire
4163 * file. This has consequences for
4164 * range_cyclic semantics (ie. it may
4165 * not be suitable for data integrity
4166 * writeout).
4167 */
4168 done_index = page->index + 1;
4169 done = 1;
4170 break;
4171 }
4172
4173 /*
4174 * the filesystem may choose to bump up nr_to_write.
4175 * We have to make sure to honor the new nr_to_write
4176 * at any time
4177 */
4178 nr_to_write_done = wbc->nr_to_write <= 0;
4179 }
4180 pagevec_release(&pvec);
4181 cond_resched();
4182 }
4183 if (!scanned && !done) {
4184 /*
4185 * We hit the last page and there is more work to be done: wrap
4186 * back to the start of the file
4187 */
4188 scanned = 1;
4189 index = 0;
4190 goto retry;
4191 }
4192
4193 if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
4194 mapping->writeback_index = done_index;
4195
4196 btrfs_add_delayed_iput(inode);
4197 return ret;
4198}
4199
4200int extent_write_full_page(struct page *page, struct writeback_control *wbc)
4201{
4202 int ret;
4203 struct extent_page_data epd = {
4204 .bio = NULL,
4205 .tree = &BTRFS_I(page->mapping->host)->io_tree,
4206 .extent_locked = 0,
4207 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4208 };
4209
4210 ret = __extent_writepage(page, wbc, &epd);
4211 ASSERT(ret <= 0);
4212 if (ret < 0) {
4213 end_write_bio(&epd, ret);
4214 return ret;
4215 }
4216
4217 ret = flush_write_bio(&epd);
4218 ASSERT(ret <= 0);
4219 return ret;
4220}
4221
4222int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
4223 int mode)
4224{
4225 int ret = 0;
4226 struct address_space *mapping = inode->i_mapping;
4227 struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
4228 struct page *page;
4229 unsigned long nr_pages = (end - start + PAGE_SIZE) >>
4230 PAGE_SHIFT;
4231
4232 struct extent_page_data epd = {
4233 .bio = NULL,
4234 .tree = tree,
4235 .extent_locked = 1,
4236 .sync_io = mode == WB_SYNC_ALL,
4237 };
4238 struct writeback_control wbc_writepages = {
4239 .sync_mode = mode,
4240 .nr_to_write = nr_pages * 2,
4241 .range_start = start,
4242 .range_end = end + 1,
4243 };
4244
4245 while (start <= end) {
4246 page = find_get_page(mapping, start >> PAGE_SHIFT);
4247 if (clear_page_dirty_for_io(page))
4248 ret = __extent_writepage(page, &wbc_writepages, &epd);
4249 else {
4250 btrfs_writepage_endio_finish_ordered(page, start,
4251 start + PAGE_SIZE - 1, 1);
4252 unlock_page(page);
4253 }
4254 put_page(page);
4255 start += PAGE_SIZE;
4256 }
4257
4258 ASSERT(ret <= 0);
4259 if (ret < 0) {
4260 end_write_bio(&epd, ret);
4261 return ret;
4262 }
4263 ret = flush_write_bio(&epd);
4264 return ret;
4265}
4266
4267int extent_writepages(struct address_space *mapping,
4268 struct writeback_control *wbc)
4269{
4270 int ret = 0;
4271 struct extent_page_data epd = {
4272 .bio = NULL,
4273 .tree = &BTRFS_I(mapping->host)->io_tree,
4274 .extent_locked = 0,
4275 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
4276 };
4277
4278 ret = extent_write_cache_pages(mapping, wbc, &epd);
4279 ASSERT(ret <= 0);
4280 if (ret < 0) {
4281 end_write_bio(&epd, ret);
4282 return ret;
4283 }
4284 ret = flush_write_bio(&epd);
4285 return ret;
4286}
4287
4288int extent_readpages(struct address_space *mapping, struct list_head *pages,
4289 unsigned nr_pages)
4290{
4291 struct bio *bio = NULL;
4292 unsigned long bio_flags = 0;
4293 struct page *pagepool[16];
4294 struct extent_map *em_cached = NULL;
4295 struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
4296 int nr = 0;
4297 u64 prev_em_start = (u64)-1;
4298
4299 while (!list_empty(pages)) {
4300 u64 contig_end = 0;
4301
4302 for (nr = 0; nr < ARRAY_SIZE(pagepool) && !list_empty(pages);) {
4303 struct page *page = lru_to_page(pages);
4304
4305 prefetchw(&page->flags);
4306 list_del(&page->lru);
4307 if (add_to_page_cache_lru(page, mapping, page->index,
4308 readahead_gfp_mask(mapping))) {
4309 put_page(page);
4310 break;
4311 }
4312
4313 pagepool[nr++] = page;
4314 contig_end = page_offset(page) + PAGE_SIZE - 1;
4315 }
4316
4317 if (nr) {
4318 u64 contig_start = page_offset(pagepool[0]);
4319
4320 ASSERT(contig_start + nr * PAGE_SIZE - 1 == contig_end);
4321
4322 contiguous_readpages(tree, pagepool, nr, contig_start,
4323 contig_end, &em_cached, &bio, &bio_flags,
4324 &prev_em_start);
4325 }
4326 }
4327
4328 if (em_cached)
4329 free_extent_map(em_cached);
4330
4331 if (bio)
4332 return submit_one_bio(bio, 0, bio_flags);
4333 return 0;
4334}
4335
4336/*
4337 * basic invalidatepage code, this waits on any locked or writeback
4338 * ranges corresponding to the page, and then deletes any extent state
4339 * records from the tree
4340 */
4341int extent_invalidatepage(struct extent_io_tree *tree,
4342 struct page *page, unsigned long offset)
4343{
4344 struct extent_state *cached_state = NULL;
4345 u64 start = page_offset(page);
4346 u64 end = start + PAGE_SIZE - 1;
4347 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
4348
4349 start += ALIGN(offset, blocksize);
4350 if (start > end)
4351 return 0;
4352
4353 lock_extent_bits(tree, start, end, &cached_state);
4354 wait_on_page_writeback(page);
4355 clear_extent_bit(tree, start, end, EXTENT_LOCKED | EXTENT_DELALLOC |
4356 EXTENT_DO_ACCOUNTING, 1, 1, &cached_state);
4357 return 0;
4358}
4359
4360/*
4361 * a helper for releasepage, this tests for areas of the page that
4362 * are locked or under IO and drops the related state bits if it is safe
4363 * to drop the page.
4364 */
4365static int try_release_extent_state(struct extent_io_tree *tree,
4366 struct page *page, gfp_t mask)
4367{
4368 u64 start = page_offset(page);
4369 u64 end = start + PAGE_SIZE - 1;
4370 int ret = 1;
4371
4372 if (test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL)) {
4373 ret = 0;
4374 } else {
4375 /*
4376 * at this point we can safely clear everything except the
4377 * locked bit and the nodatasum bit
4378 */
4379 ret = __clear_extent_bit(tree, start, end,
4380 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
4381 0, 0, NULL, mask, NULL);
4382
4383 /* if clear_extent_bit failed for enomem reasons,
4384 * we can't allow the release to continue.
4385 */
4386 if (ret < 0)
4387 ret = 0;
4388 else
4389 ret = 1;
4390 }
4391 return ret;
4392}
4393
4394/*
4395 * a helper for releasepage. As long as there are no locked extents
4396 * in the range corresponding to the page, both state records and extent
4397 * map records are removed
4398 */
4399int try_release_extent_mapping(struct page *page, gfp_t mask)
4400{
4401 struct extent_map *em;
4402 u64 start = page_offset(page);
4403 u64 end = start + PAGE_SIZE - 1;
4404 struct btrfs_inode *btrfs_inode = BTRFS_I(page->mapping->host);
4405 struct extent_io_tree *tree = &btrfs_inode->io_tree;
4406 struct extent_map_tree *map = &btrfs_inode->extent_tree;
4407
4408 if (gfpflags_allow_blocking(mask) &&
4409 page->mapping->host->i_size > SZ_16M) {
4410 u64 len;
4411 while (start <= end) {
4412 len = end - start + 1;
4413 write_lock(&map->lock);
4414 em = lookup_extent_mapping(map, start, len);
4415 if (!em) {
4416 write_unlock(&map->lock);
4417 break;
4418 }
4419 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
4420 em->start != start) {
4421 write_unlock(&map->lock);
4422 free_extent_map(em);
4423 break;
4424 }
4425 if (!test_range_bit(tree, em->start,
4426 extent_map_end(em) - 1,
4427 EXTENT_LOCKED, 0, NULL)) {
4428 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4429 &btrfs_inode->runtime_flags);
4430 remove_extent_mapping(map, em);
4431 /* once for the rb tree */
4432 free_extent_map(em);
4433 }
4434 start = extent_map_end(em);
4435 write_unlock(&map->lock);
4436
4437 /* once for us */
4438 free_extent_map(em);
4439 }
4440 }
4441 return try_release_extent_state(tree, page, mask);
4442}
4443
4444/*
4445 * helper function for fiemap, which doesn't want to see any holes.
4446 * This maps until we find something past 'last'
4447 */
4448static struct extent_map *get_extent_skip_holes(struct inode *inode,
4449 u64 offset, u64 last)
4450{
4451 u64 sectorsize = btrfs_inode_sectorsize(inode);
4452 struct extent_map *em;
4453 u64 len;
4454
4455 if (offset >= last)
4456 return NULL;
4457
4458 while (1) {
4459 len = last - offset;
4460 if (len == 0)
4461 break;
4462 len = ALIGN(len, sectorsize);
4463 em = btrfs_get_extent_fiemap(BTRFS_I(inode), offset, len);
4464 if (IS_ERR_OR_NULL(em))
4465 return em;
4466
4467 /* if this isn't a hole return it */
4468 if (em->block_start != EXTENT_MAP_HOLE)
4469 return em;
4470
4471 /* this is a hole, advance to the next extent */
4472 offset = extent_map_end(em);
4473 free_extent_map(em);
4474 if (offset >= last)
4475 break;
4476 }
4477 return NULL;
4478}
4479
4480/*
4481 * To cache previous fiemap extent
4482 *
4483 * Will be used for merging fiemap extent
4484 */
4485struct fiemap_cache {
4486 u64 offset;
4487 u64 phys;
4488 u64 len;
4489 u32 flags;
4490 bool cached;
4491};
4492
4493/*
4494 * Helper to submit fiemap extent.
4495 *
4496 * Will try to merge current fiemap extent specified by @offset, @phys,
4497 * @len and @flags with cached one.
4498 * And only when we fails to merge, cached one will be submitted as
4499 * fiemap extent.
4500 *
4501 * Return value is the same as fiemap_fill_next_extent().
4502 */
4503static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
4504 struct fiemap_cache *cache,
4505 u64 offset, u64 phys, u64 len, u32 flags)
4506{
4507 int ret = 0;
4508
4509 if (!cache->cached)
4510 goto assign;
4511
4512 /*
4513 * Sanity check, extent_fiemap() should have ensured that new
4514 * fiemap extent won't overlap with cached one.
4515 * Not recoverable.
4516 *
4517 * NOTE: Physical address can overlap, due to compression
4518 */
4519 if (cache->offset + cache->len > offset) {
4520 WARN_ON(1);
4521 return -EINVAL;
4522 }
4523
4524 /*
4525 * Only merges fiemap extents if
4526 * 1) Their logical addresses are continuous
4527 *
4528 * 2) Their physical addresses are continuous
4529 * So truly compressed (physical size smaller than logical size)
4530 * extents won't get merged with each other
4531 *
4532 * 3) Share same flags except FIEMAP_EXTENT_LAST
4533 * So regular extent won't get merged with prealloc extent
4534 */
4535 if (cache->offset + cache->len == offset &&
4536 cache->phys + cache->len == phys &&
4537 (cache->flags & ~FIEMAP_EXTENT_LAST) ==
4538 (flags & ~FIEMAP_EXTENT_LAST)) {
4539 cache->len += len;
4540 cache->flags |= flags;
4541 goto try_submit_last;
4542 }
4543
4544 /* Not mergeable, need to submit cached one */
4545 ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
4546 cache->len, cache->flags);
4547 cache->cached = false;
4548 if (ret)
4549 return ret;
4550assign:
4551 cache->cached = true;
4552 cache->offset = offset;
4553 cache->phys = phys;
4554 cache->len = len;
4555 cache->flags = flags;
4556try_submit_last:
4557 if (cache->flags & FIEMAP_EXTENT_LAST) {
4558 ret = fiemap_fill_next_extent(fieinfo, cache->offset,
4559 cache->phys, cache->len, cache->flags);
4560 cache->cached = false;
4561 }
4562 return ret;
4563}
4564
4565/*
4566 * Emit last fiemap cache
4567 *
4568 * The last fiemap cache may still be cached in the following case:
4569 * 0 4k 8k
4570 * |<- Fiemap range ->|
4571 * |<------------ First extent ----------->|
4572 *
4573 * In this case, the first extent range will be cached but not emitted.
4574 * So we must emit it before ending extent_fiemap().
4575 */
4576static int emit_last_fiemap_cache(struct fiemap_extent_info *fieinfo,
4577 struct fiemap_cache *cache)
4578{
4579 int ret;
4580
4581 if (!cache->cached)
4582 return 0;
4583
4584 ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
4585 cache->len, cache->flags);
4586 cache->cached = false;
4587 if (ret > 0)
4588 ret = 0;
4589 return ret;
4590}
4591
4592int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4593 __u64 start, __u64 len)
4594{
4595 int ret = 0;
4596 u64 off = start;
4597 u64 max = start + len;
4598 u32 flags = 0;
4599 u32 found_type;
4600 u64 last;
4601 u64 last_for_get_extent = 0;
4602 u64 disko = 0;
4603 u64 isize = i_size_read(inode);
4604 struct btrfs_key found_key;
4605 struct extent_map *em = NULL;
4606 struct extent_state *cached_state = NULL;
4607 struct btrfs_path *path;
4608 struct btrfs_root *root = BTRFS_I(inode)->root;
4609 struct fiemap_cache cache = { 0 };
4610 struct ulist *roots;
4611 struct ulist *tmp_ulist;
4612 int end = 0;
4613 u64 em_start = 0;
4614 u64 em_len = 0;
4615 u64 em_end = 0;
4616
4617 if (len == 0)
4618 return -EINVAL;
4619
4620 path = btrfs_alloc_path();
4621 if (!path)
4622 return -ENOMEM;
4623 path->leave_spinning = 1;
4624
4625 roots = ulist_alloc(GFP_KERNEL);
4626 tmp_ulist = ulist_alloc(GFP_KERNEL);
4627 if (!roots || !tmp_ulist) {
4628 ret = -ENOMEM;
4629 goto out_free_ulist;
4630 }
4631
4632 start = round_down(start, btrfs_inode_sectorsize(inode));
4633 len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
4634
4635 /*
4636 * lookup the last file extent. We're not using i_size here
4637 * because there might be preallocation past i_size
4638 */
4639 ret = btrfs_lookup_file_extent(NULL, root, path,
4640 btrfs_ino(BTRFS_I(inode)), -1, 0);
4641 if (ret < 0) {
4642 goto out_free_ulist;
4643 } else {
4644 WARN_ON(!ret);
4645 if (ret == 1)
4646 ret = 0;
4647 }
4648
4649 path->slots[0]--;
4650 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
4651 found_type = found_key.type;
4652
4653 /* No extents, but there might be delalloc bits */
4654 if (found_key.objectid != btrfs_ino(BTRFS_I(inode)) ||
4655 found_type != BTRFS_EXTENT_DATA_KEY) {
4656 /* have to trust i_size as the end */
4657 last = (u64)-1;
4658 last_for_get_extent = isize;
4659 } else {
4660 /*
4661 * remember the start of the last extent. There are a
4662 * bunch of different factors that go into the length of the
4663 * extent, so its much less complex to remember where it started
4664 */
4665 last = found_key.offset;
4666 last_for_get_extent = last + 1;
4667 }
4668 btrfs_release_path(path);
4669
4670 /*
4671 * we might have some extents allocated but more delalloc past those
4672 * extents. so, we trust isize unless the start of the last extent is
4673 * beyond isize
4674 */
4675 if (last < isize) {
4676 last = (u64)-1;
4677 last_for_get_extent = isize;
4678 }
4679
4680 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4681 &cached_state);
4682
4683 em = get_extent_skip_holes(inode, start, last_for_get_extent);
4684 if (!em)
4685 goto out;
4686 if (IS_ERR(em)) {
4687 ret = PTR_ERR(em);
4688 goto out;
4689 }
4690
4691 while (!end) {
4692 u64 offset_in_extent = 0;
4693
4694 /* break if the extent we found is outside the range */
4695 if (em->start >= max || extent_map_end(em) < off)
4696 break;
4697
4698 /*
4699 * get_extent may return an extent that starts before our
4700 * requested range. We have to make sure the ranges
4701 * we return to fiemap always move forward and don't
4702 * overlap, so adjust the offsets here
4703 */
4704 em_start = max(em->start, off);
4705
4706 /*
4707 * record the offset from the start of the extent
4708 * for adjusting the disk offset below. Only do this if the
4709 * extent isn't compressed since our in ram offset may be past
4710 * what we have actually allocated on disk.
4711 */
4712 if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4713 offset_in_extent = em_start - em->start;
4714 em_end = extent_map_end(em);
4715 em_len = em_end - em_start;
4716 flags = 0;
4717 if (em->block_start < EXTENT_MAP_LAST_BYTE)
4718 disko = em->block_start + offset_in_extent;
4719 else
4720 disko = 0;
4721
4722 /*
4723 * bump off for our next call to get_extent
4724 */
4725 off = extent_map_end(em);
4726 if (off >= max)
4727 end = 1;
4728
4729 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
4730 end = 1;
4731 flags |= FIEMAP_EXTENT_LAST;
4732 } else if (em->block_start == EXTENT_MAP_INLINE) {
4733 flags |= (FIEMAP_EXTENT_DATA_INLINE |
4734 FIEMAP_EXTENT_NOT_ALIGNED);
4735 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
4736 flags |= (FIEMAP_EXTENT_DELALLOC |
4737 FIEMAP_EXTENT_UNKNOWN);
4738 } else if (fieinfo->fi_extents_max) {
4739 u64 bytenr = em->block_start -
4740 (em->start - em->orig_start);
4741
4742 /*
4743 * As btrfs supports shared space, this information
4744 * can be exported to userspace tools via
4745 * flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0
4746 * then we're just getting a count and we can skip the
4747 * lookup stuff.
4748 */
4749 ret = btrfs_check_shared(root,
4750 btrfs_ino(BTRFS_I(inode)),
4751 bytenr, roots, tmp_ulist);
4752 if (ret < 0)
4753 goto out_free;
4754 if (ret)
4755 flags |= FIEMAP_EXTENT_SHARED;
4756 ret = 0;
4757 }
4758 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
4759 flags |= FIEMAP_EXTENT_ENCODED;
4760 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
4761 flags |= FIEMAP_EXTENT_UNWRITTEN;
4762
4763 free_extent_map(em);
4764 em = NULL;
4765 if ((em_start >= last) || em_len == (u64)-1 ||
4766 (last == (u64)-1 && isize <= em_end)) {
4767 flags |= FIEMAP_EXTENT_LAST;
4768 end = 1;
4769 }
4770
4771 /* now scan forward to see if this is really the last extent. */
4772 em = get_extent_skip_holes(inode, off, last_for_get_extent);
4773 if (IS_ERR(em)) {
4774 ret = PTR_ERR(em);
4775 goto out;
4776 }
4777 if (!em) {
4778 flags |= FIEMAP_EXTENT_LAST;
4779 end = 1;
4780 }
4781 ret = emit_fiemap_extent(fieinfo, &cache, em_start, disko,
4782 em_len, flags);
4783 if (ret) {
4784 if (ret == 1)
4785 ret = 0;
4786 goto out_free;
4787 }
4788 }
4789out_free:
4790 if (!ret)
4791 ret = emit_last_fiemap_cache(fieinfo, &cache);
4792 free_extent_map(em);
4793out:
4794 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4795 &cached_state);
4796
4797out_free_ulist:
4798 btrfs_free_path(path);
4799 ulist_free(roots);
4800 ulist_free(tmp_ulist);
4801 return ret;
4802}
4803
4804static void __free_extent_buffer(struct extent_buffer *eb)
4805{
4806 btrfs_leak_debug_del(&eb->leak_list);
4807 kmem_cache_free(extent_buffer_cache, eb);
4808}
4809
4810int extent_buffer_under_io(struct extent_buffer *eb)
4811{
4812 return (atomic_read(&eb->io_pages) ||
4813 test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
4814 test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4815}
4816
4817/*
4818 * Release all pages attached to the extent buffer.
4819 */
4820static void btrfs_release_extent_buffer_pages(struct extent_buffer *eb)
4821{
4822 int i;
4823 int num_pages;
4824 int mapped = !test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
4825
4826 BUG_ON(extent_buffer_under_io(eb));
4827
4828 num_pages = num_extent_pages(eb);
4829 for (i = 0; i < num_pages; i++) {
4830 struct page *page = eb->pages[i];
4831
4832 if (!page)
4833 continue;
4834 if (mapped)
4835 spin_lock(&page->mapping->private_lock);
4836 /*
4837 * We do this since we'll remove the pages after we've
4838 * removed the eb from the radix tree, so we could race
4839 * and have this page now attached to the new eb. So
4840 * only clear page_private if it's still connected to
4841 * this eb.
4842 */
4843 if (PagePrivate(page) &&
4844 page->private == (unsigned long)eb) {
4845 BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
4846 BUG_ON(PageDirty(page));
4847 BUG_ON(PageWriteback(page));
4848 /*
4849 * We need to make sure we haven't be attached
4850 * to a new eb.
4851 */
4852 ClearPagePrivate(page);
4853 set_page_private(page, 0);
4854 /* One for the page private */
4855 put_page(page);
4856 }
4857
4858 if (mapped)
4859 spin_unlock(&page->mapping->private_lock);
4860
4861 /* One for when we allocated the page */
4862 put_page(page);
4863 }
4864}
4865
4866/*
4867 * Helper for releasing the extent buffer.
4868 */
4869static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
4870{
4871 btrfs_release_extent_buffer_pages(eb);
4872 __free_extent_buffer(eb);
4873}
4874
4875static struct extent_buffer *
4876__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
4877 unsigned long len)
4878{
4879 struct extent_buffer *eb = NULL;
4880
4881 eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
4882 eb->start = start;
4883 eb->len = len;
4884 eb->fs_info = fs_info;
4885 eb->bflags = 0;
4886 rwlock_init(&eb->lock);
4887 atomic_set(&eb->blocking_readers, 0);
4888 eb->blocking_writers = 0;
4889 eb->lock_nested = false;
4890 init_waitqueue_head(&eb->write_lock_wq);
4891 init_waitqueue_head(&eb->read_lock_wq);
4892
4893 btrfs_leak_debug_add(&eb->leak_list, &buffers);
4894
4895 spin_lock_init(&eb->refs_lock);
4896 atomic_set(&eb->refs, 1);
4897 atomic_set(&eb->io_pages, 0);
4898
4899 /*
4900 * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
4901 */
4902 BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
4903 > MAX_INLINE_EXTENT_BUFFER_SIZE);
4904 BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
4905
4906#ifdef CONFIG_BTRFS_DEBUG
4907 eb->spinning_writers = 0;
4908 atomic_set(&eb->spinning_readers, 0);
4909 atomic_set(&eb->read_locks, 0);
4910 eb->write_locks = 0;
4911#endif
4912
4913 return eb;
4914}
4915
4916struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
4917{
4918 int i;
4919 struct page *p;
4920 struct extent_buffer *new;
4921 int num_pages = num_extent_pages(src);
4922
4923 new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
4924 if (new == NULL)
4925 return NULL;
4926
4927 for (i = 0; i < num_pages; i++) {
4928 p = alloc_page(GFP_NOFS);
4929 if (!p) {
4930 btrfs_release_extent_buffer(new);
4931 return NULL;
4932 }
4933 attach_extent_buffer_page(new, p);
4934 WARN_ON(PageDirty(p));
4935 SetPageUptodate(p);
4936 new->pages[i] = p;
4937 copy_page(page_address(p), page_address(src->pages[i]));
4938 }
4939
4940 set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
4941 set_bit(EXTENT_BUFFER_UNMAPPED, &new->bflags);
4942
4943 return new;
4944}
4945
4946struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4947 u64 start, unsigned long len)
4948{
4949 struct extent_buffer *eb;
4950 int num_pages;
4951 int i;
4952
4953 eb = __alloc_extent_buffer(fs_info, start, len);
4954 if (!eb)
4955 return NULL;
4956
4957 num_pages = num_extent_pages(eb);
4958 for (i = 0; i < num_pages; i++) {
4959 eb->pages[i] = alloc_page(GFP_NOFS);
4960 if (!eb->pages[i])
4961 goto err;
4962 }
4963 set_extent_buffer_uptodate(eb);
4964 btrfs_set_header_nritems(eb, 0);
4965 set_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
4966
4967 return eb;
4968err:
4969 for (; i > 0; i--)
4970 __free_page(eb->pages[i - 1]);
4971 __free_extent_buffer(eb);
4972 return NULL;
4973}
4974
4975struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
4976 u64 start)
4977{
4978 return __alloc_dummy_extent_buffer(fs_info, start, fs_info->nodesize);
4979}
4980
4981static void check_buffer_tree_ref(struct extent_buffer *eb)
4982{
4983 int refs;
4984 /* the ref bit is tricky. We have to make sure it is set
4985 * if we have the buffer dirty. Otherwise the
4986 * code to free a buffer can end up dropping a dirty
4987 * page
4988 *
4989 * Once the ref bit is set, it won't go away while the
4990 * buffer is dirty or in writeback, and it also won't
4991 * go away while we have the reference count on the
4992 * eb bumped.
4993 *
4994 * We can't just set the ref bit without bumping the
4995 * ref on the eb because free_extent_buffer might
4996 * see the ref bit and try to clear it. If this happens
4997 * free_extent_buffer might end up dropping our original
4998 * ref by mistake and freeing the page before we are able
4999 * to add one more ref.
5000 *
5001 * So bump the ref count first, then set the bit. If someone
5002 * beat us to it, drop the ref we added.
5003 */
5004 refs = atomic_read(&eb->refs);
5005 if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5006 return;
5007
5008 spin_lock(&eb->refs_lock);
5009 if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5010 atomic_inc(&eb->refs);
5011 spin_unlock(&eb->refs_lock);
5012}
5013
5014static void mark_extent_buffer_accessed(struct extent_buffer *eb,
5015 struct page *accessed)
5016{
5017 int num_pages, i;
5018
5019 check_buffer_tree_ref(eb);
5020
5021 num_pages = num_extent_pages(eb);
5022 for (i = 0; i < num_pages; i++) {
5023 struct page *p = eb->pages[i];
5024
5025 if (p != accessed)
5026 mark_page_accessed(p);
5027 }
5028}
5029
5030struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
5031 u64 start)
5032{
5033 struct extent_buffer *eb;
5034
5035 rcu_read_lock();
5036 eb = radix_tree_lookup(&fs_info->buffer_radix,
5037 start >> PAGE_SHIFT);
5038 if (eb && atomic_inc_not_zero(&eb->refs)) {
5039 rcu_read_unlock();
5040 /*
5041 * Lock our eb's refs_lock to avoid races with
5042 * free_extent_buffer. When we get our eb it might be flagged
5043 * with EXTENT_BUFFER_STALE and another task running
5044 * free_extent_buffer might have seen that flag set,
5045 * eb->refs == 2, that the buffer isn't under IO (dirty and
5046 * writeback flags not set) and it's still in the tree (flag
5047 * EXTENT_BUFFER_TREE_REF set), therefore being in the process
5048 * of decrementing the extent buffer's reference count twice.
5049 * So here we could race and increment the eb's reference count,
5050 * clear its stale flag, mark it as dirty and drop our reference
5051 * before the other task finishes executing free_extent_buffer,
5052 * which would later result in an attempt to free an extent
5053 * buffer that is dirty.
5054 */
5055 if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
5056 spin_lock(&eb->refs_lock);
5057 spin_unlock(&eb->refs_lock);
5058 }
5059 mark_extent_buffer_accessed(eb, NULL);
5060 return eb;
5061 }
5062 rcu_read_unlock();
5063
5064 return NULL;
5065}
5066
5067#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5068struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
5069 u64 start)
5070{
5071 struct extent_buffer *eb, *exists = NULL;
5072 int ret;
5073
5074 eb = find_extent_buffer(fs_info, start);
5075 if (eb)
5076 return eb;
5077 eb = alloc_dummy_extent_buffer(fs_info, start);
5078 if (!eb)
5079 return NULL;
5080 eb->fs_info = fs_info;
5081again:
5082 ret = radix_tree_preload(GFP_NOFS);
5083 if (ret)
5084 goto free_eb;
5085 spin_lock(&fs_info->buffer_lock);
5086 ret = radix_tree_insert(&fs_info->buffer_radix,
5087 start >> PAGE_SHIFT, eb);
5088 spin_unlock(&fs_info->buffer_lock);
5089 radix_tree_preload_end();
5090 if (ret == -EEXIST) {
5091 exists = find_extent_buffer(fs_info, start);
5092 if (exists)
5093 goto free_eb;
5094 else
5095 goto again;
5096 }
5097 check_buffer_tree_ref(eb);
5098 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
5099
5100 return eb;
5101free_eb:
5102 btrfs_release_extent_buffer(eb);
5103 return exists;
5104}
5105#endif
5106
5107struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
5108 u64 start)
5109{
5110 unsigned long len = fs_info->nodesize;
5111 int num_pages;
5112 int i;
5113 unsigned long index = start >> PAGE_SHIFT;
5114 struct extent_buffer *eb;
5115 struct extent_buffer *exists = NULL;
5116 struct page *p;
5117 struct address_space *mapping = fs_info->btree_inode->i_mapping;
5118 int uptodate = 1;
5119 int ret;
5120
5121 if (!IS_ALIGNED(start, fs_info->sectorsize)) {
5122 btrfs_err(fs_info, "bad tree block start %llu", start);
5123 return ERR_PTR(-EINVAL);
5124 }
5125
5126 eb = find_extent_buffer(fs_info, start);
5127 if (eb)
5128 return eb;
5129
5130 eb = __alloc_extent_buffer(fs_info, start, len);
5131 if (!eb)
5132 return ERR_PTR(-ENOMEM);
5133
5134 num_pages = num_extent_pages(eb);
5135 for (i = 0; i < num_pages; i++, index++) {
5136 p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
5137 if (!p) {
5138 exists = ERR_PTR(-ENOMEM);
5139 goto free_eb;
5140 }
5141
5142 spin_lock(&mapping->private_lock);
5143 if (PagePrivate(p)) {
5144 /*
5145 * We could have already allocated an eb for this page
5146 * and attached one so lets see if we can get a ref on
5147 * the existing eb, and if we can we know it's good and
5148 * we can just return that one, else we know we can just
5149 * overwrite page->private.
5150 */
5151 exists = (struct extent_buffer *)p->private;
5152 if (atomic_inc_not_zero(&exists->refs)) {
5153 spin_unlock(&mapping->private_lock);
5154 unlock_page(p);
5155 put_page(p);
5156 mark_extent_buffer_accessed(exists, p);
5157 goto free_eb;
5158 }
5159 exists = NULL;
5160
5161 /*
5162 * Do this so attach doesn't complain and we need to
5163 * drop the ref the old guy had.
5164 */
5165 ClearPagePrivate(p);
5166 WARN_ON(PageDirty(p));
5167 put_page(p);
5168 }
5169 attach_extent_buffer_page(eb, p);
5170 spin_unlock(&mapping->private_lock);
5171 WARN_ON(PageDirty(p));
5172 eb->pages[i] = p;
5173 if (!PageUptodate(p))
5174 uptodate = 0;
5175
5176 /*
5177 * We can't unlock the pages just yet since the extent buffer
5178 * hasn't been properly inserted in the radix tree, this
5179 * opens a race with btree_releasepage which can free a page
5180 * while we are still filling in all pages for the buffer and
5181 * we could crash.
5182 */
5183 }
5184 if (uptodate)
5185 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5186again:
5187 ret = radix_tree_preload(GFP_NOFS);
5188 if (ret) {
5189 exists = ERR_PTR(ret);
5190 goto free_eb;
5191 }
5192
5193 spin_lock(&fs_info->buffer_lock);
5194 ret = radix_tree_insert(&fs_info->buffer_radix,
5195 start >> PAGE_SHIFT, eb);
5196 spin_unlock(&fs_info->buffer_lock);
5197 radix_tree_preload_end();
5198 if (ret == -EEXIST) {
5199 exists = find_extent_buffer(fs_info, start);
5200 if (exists)
5201 goto free_eb;
5202 else
5203 goto again;
5204 }
5205 /* add one reference for the tree */
5206 check_buffer_tree_ref(eb);
5207 set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
5208
5209 /*
5210 * Now it's safe to unlock the pages because any calls to
5211 * btree_releasepage will correctly detect that a page belongs to a
5212 * live buffer and won't free them prematurely.
5213 */
5214 for (i = 0; i < num_pages; i++)
5215 unlock_page(eb->pages[i]);
5216 return eb;
5217
5218free_eb:
5219 WARN_ON(!atomic_dec_and_test(&eb->refs));
5220 for (i = 0; i < num_pages; i++) {
5221 if (eb->pages[i])
5222 unlock_page(eb->pages[i]);
5223 }
5224
5225 btrfs_release_extent_buffer(eb);
5226 return exists;
5227}
5228
5229static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
5230{
5231 struct extent_buffer *eb =
5232 container_of(head, struct extent_buffer, rcu_head);
5233
5234 __free_extent_buffer(eb);
5235}
5236
5237static int release_extent_buffer(struct extent_buffer *eb)
5238{
5239 lockdep_assert_held(&eb->refs_lock);
5240
5241 WARN_ON(atomic_read(&eb->refs) == 0);
5242 if (atomic_dec_and_test(&eb->refs)) {
5243 if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
5244 struct btrfs_fs_info *fs_info = eb->fs_info;
5245
5246 spin_unlock(&eb->refs_lock);
5247
5248 spin_lock(&fs_info->buffer_lock);
5249 radix_tree_delete(&fs_info->buffer_radix,
5250 eb->start >> PAGE_SHIFT);
5251 spin_unlock(&fs_info->buffer_lock);
5252 } else {
5253 spin_unlock(&eb->refs_lock);
5254 }
5255
5256 /* Should be safe to release our pages at this point */
5257 btrfs_release_extent_buffer_pages(eb);
5258#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5259 if (unlikely(test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags))) {
5260 __free_extent_buffer(eb);
5261 return 1;
5262 }
5263#endif
5264 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
5265 return 1;
5266 }
5267 spin_unlock(&eb->refs_lock);
5268
5269 return 0;
5270}
5271
5272void free_extent_buffer(struct extent_buffer *eb)
5273{
5274 int refs;
5275 int old;
5276 if (!eb)
5277 return;
5278
5279 while (1) {
5280 refs = atomic_read(&eb->refs);
5281 if ((!test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) && refs <= 3)
5282 || (test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) &&
5283 refs == 1))
5284 break;
5285 old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
5286 if (old == refs)
5287 return;
5288 }
5289
5290 spin_lock(&eb->refs_lock);
5291 if (atomic_read(&eb->refs) == 2 &&
5292 test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
5293 !extent_buffer_under_io(eb) &&
5294 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5295 atomic_dec(&eb->refs);
5296
5297 /*
5298 * I know this is terrible, but it's temporary until we stop tracking
5299 * the uptodate bits and such for the extent buffers.
5300 */
5301 release_extent_buffer(eb);
5302}
5303
5304void free_extent_buffer_stale(struct extent_buffer *eb)
5305{
5306 if (!eb)
5307 return;
5308
5309 spin_lock(&eb->refs_lock);
5310 set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
5311
5312 if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
5313 test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
5314 atomic_dec(&eb->refs);
5315 release_extent_buffer(eb);
5316}
5317
5318void clear_extent_buffer_dirty(struct extent_buffer *eb)
5319{
5320 int i;
5321 int num_pages;
5322 struct page *page;
5323
5324 num_pages = num_extent_pages(eb);
5325
5326 for (i = 0; i < num_pages; i++) {
5327 page = eb->pages[i];
5328 if (!PageDirty(page))
5329 continue;
5330
5331 lock_page(page);
5332 WARN_ON(!PagePrivate(page));
5333
5334 clear_page_dirty_for_io(page);
5335 xa_lock_irq(&page->mapping->i_pages);
5336 if (!PageDirty(page))
5337 __xa_clear_mark(&page->mapping->i_pages,
5338 page_index(page), PAGECACHE_TAG_DIRTY);
5339 xa_unlock_irq(&page->mapping->i_pages);
5340 ClearPageError(page);
5341 unlock_page(page);
5342 }
5343 WARN_ON(atomic_read(&eb->refs) == 0);
5344}
5345
5346bool set_extent_buffer_dirty(struct extent_buffer *eb)
5347{
5348 int i;
5349 int num_pages;
5350 bool was_dirty;
5351
5352 check_buffer_tree_ref(eb);
5353
5354 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
5355
5356 num_pages = num_extent_pages(eb);
5357 WARN_ON(atomic_read(&eb->refs) == 0);
5358 WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
5359
5360 if (!was_dirty)
5361 for (i = 0; i < num_pages; i++)
5362 set_page_dirty(eb->pages[i]);
5363
5364#ifdef CONFIG_BTRFS_DEBUG
5365 for (i = 0; i < num_pages; i++)
5366 ASSERT(PageDirty(eb->pages[i]));
5367#endif
5368
5369 return was_dirty;
5370}
5371
5372void clear_extent_buffer_uptodate(struct extent_buffer *eb)
5373{
5374 int i;
5375 struct page *page;
5376 int num_pages;
5377
5378 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5379 num_pages = num_extent_pages(eb);
5380 for (i = 0; i < num_pages; i++) {
5381 page = eb->pages[i];
5382 if (page)
5383 ClearPageUptodate(page);
5384 }
5385}
5386
5387void set_extent_buffer_uptodate(struct extent_buffer *eb)
5388{
5389 int i;
5390 struct page *page;
5391 int num_pages;
5392
5393 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5394 num_pages = num_extent_pages(eb);
5395 for (i = 0; i < num_pages; i++) {
5396 page = eb->pages[i];
5397 SetPageUptodate(page);
5398 }
5399}
5400
5401int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num)
5402{
5403 int i;
5404 struct page *page;
5405 int err;
5406 int ret = 0;
5407 int locked_pages = 0;
5408 int all_uptodate = 1;
5409 int num_pages;
5410 unsigned long num_reads = 0;
5411 struct bio *bio = NULL;
5412 unsigned long bio_flags = 0;
5413 struct extent_io_tree *tree = &BTRFS_I(eb->fs_info->btree_inode)->io_tree;
5414
5415 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
5416 return 0;
5417
5418 num_pages = num_extent_pages(eb);
5419 for (i = 0; i < num_pages; i++) {
5420 page = eb->pages[i];
5421 if (wait == WAIT_NONE) {
5422 if (!trylock_page(page))
5423 goto unlock_exit;
5424 } else {
5425 lock_page(page);
5426 }
5427 locked_pages++;
5428 }
5429 /*
5430 * We need to firstly lock all pages to make sure that
5431 * the uptodate bit of our pages won't be affected by
5432 * clear_extent_buffer_uptodate().
5433 */
5434 for (i = 0; i < num_pages; i++) {
5435 page = eb->pages[i];
5436 if (!PageUptodate(page)) {
5437 num_reads++;
5438 all_uptodate = 0;
5439 }
5440 }
5441
5442 if (all_uptodate) {
5443 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5444 goto unlock_exit;
5445 }
5446
5447 clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
5448 eb->read_mirror = 0;
5449 atomic_set(&eb->io_pages, num_reads);
5450 for (i = 0; i < num_pages; i++) {
5451 page = eb->pages[i];
5452
5453 if (!PageUptodate(page)) {
5454 if (ret) {
5455 atomic_dec(&eb->io_pages);
5456 unlock_page(page);
5457 continue;
5458 }
5459
5460 ClearPageError(page);
5461 err = __extent_read_full_page(tree, page,
5462 btree_get_extent, &bio,
5463 mirror_num, &bio_flags,
5464 REQ_META);
5465 if (err) {
5466 ret = err;
5467 /*
5468 * We use &bio in above __extent_read_full_page,
5469 * so we ensure that if it returns error, the
5470 * current page fails to add itself to bio and
5471 * it's been unlocked.
5472 *
5473 * We must dec io_pages by ourselves.
5474 */
5475 atomic_dec(&eb->io_pages);
5476 }
5477 } else {
5478 unlock_page(page);
5479 }
5480 }
5481
5482 if (bio) {
5483 err = submit_one_bio(bio, mirror_num, bio_flags);
5484 if (err)
5485 return err;
5486 }
5487
5488 if (ret || wait != WAIT_COMPLETE)
5489 return ret;
5490
5491 for (i = 0; i < num_pages; i++) {
5492 page = eb->pages[i];
5493 wait_on_page_locked(page);
5494 if (!PageUptodate(page))
5495 ret = -EIO;
5496 }
5497
5498 return ret;
5499
5500unlock_exit:
5501 while (locked_pages > 0) {
5502 locked_pages--;
5503 page = eb->pages[locked_pages];
5504 unlock_page(page);
5505 }
5506 return ret;
5507}
5508
5509void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
5510 unsigned long start, unsigned long len)
5511{
5512 size_t cur;
5513 size_t offset;
5514 struct page *page;
5515 char *kaddr;
5516 char *dst = (char *)dstv;
5517 size_t start_offset = offset_in_page(eb->start);
5518 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5519
5520 if (start + len > eb->len) {
5521 WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
5522 eb->start, eb->len, start, len);
5523 memset(dst, 0, len);
5524 return;
5525 }
5526
5527 offset = offset_in_page(start_offset + start);
5528
5529 while (len > 0) {
5530 page = eb->pages[i];
5531
5532 cur = min(len, (PAGE_SIZE - offset));
5533 kaddr = page_address(page);
5534 memcpy(dst, kaddr + offset, cur);
5535
5536 dst += cur;
5537 len -= cur;
5538 offset = 0;
5539 i++;
5540 }
5541}
5542
5543int read_extent_buffer_to_user(const struct extent_buffer *eb,
5544 void __user *dstv,
5545 unsigned long start, unsigned long len)
5546{
5547 size_t cur;
5548 size_t offset;
5549 struct page *page;
5550 char *kaddr;
5551 char __user *dst = (char __user *)dstv;
5552 size_t start_offset = offset_in_page(eb->start);
5553 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5554 int ret = 0;
5555
5556 WARN_ON(start > eb->len);
5557 WARN_ON(start + len > eb->start + eb->len);
5558
5559 offset = offset_in_page(start_offset + start);
5560
5561 while (len > 0) {
5562 page = eb->pages[i];
5563
5564 cur = min(len, (PAGE_SIZE - offset));
5565 kaddr = page_address(page);
5566 if (copy_to_user(dst, kaddr + offset, cur)) {
5567 ret = -EFAULT;
5568 break;
5569 }
5570
5571 dst += cur;
5572 len -= cur;
5573 offset = 0;
5574 i++;
5575 }
5576
5577 return ret;
5578}
5579
5580/*
5581 * return 0 if the item is found within a page.
5582 * return 1 if the item spans two pages.
5583 * return -EINVAL otherwise.
5584 */
5585int map_private_extent_buffer(const struct extent_buffer *eb,
5586 unsigned long start, unsigned long min_len,
5587 char **map, unsigned long *map_start,
5588 unsigned long *map_len)
5589{
5590 size_t offset;
5591 char *kaddr;
5592 struct page *p;
5593 size_t start_offset = offset_in_page(eb->start);
5594 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5595 unsigned long end_i = (start_offset + start + min_len - 1) >>
5596 PAGE_SHIFT;
5597
5598 if (start + min_len > eb->len) {
5599 WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
5600 eb->start, eb->len, start, min_len);
5601 return -EINVAL;
5602 }
5603
5604 if (i != end_i)
5605 return 1;
5606
5607 if (i == 0) {
5608 offset = start_offset;
5609 *map_start = 0;
5610 } else {
5611 offset = 0;
5612 *map_start = ((u64)i << PAGE_SHIFT) - start_offset;
5613 }
5614
5615 p = eb->pages[i];
5616 kaddr = page_address(p);
5617 *map = kaddr + offset;
5618 *map_len = PAGE_SIZE - offset;
5619 return 0;
5620}
5621
5622int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
5623 unsigned long start, unsigned long len)
5624{
5625 size_t cur;
5626 size_t offset;
5627 struct page *page;
5628 char *kaddr;
5629 char *ptr = (char *)ptrv;
5630 size_t start_offset = offset_in_page(eb->start);
5631 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5632 int ret = 0;
5633
5634 WARN_ON(start > eb->len);
5635 WARN_ON(start + len > eb->start + eb->len);
5636
5637 offset = offset_in_page(start_offset + start);
5638
5639 while (len > 0) {
5640 page = eb->pages[i];
5641
5642 cur = min(len, (PAGE_SIZE - offset));
5643
5644 kaddr = page_address(page);
5645 ret = memcmp(ptr, kaddr + offset, cur);
5646 if (ret)
5647 break;
5648
5649 ptr += cur;
5650 len -= cur;
5651 offset = 0;
5652 i++;
5653 }
5654 return ret;
5655}
5656
5657void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
5658 const void *srcv)
5659{
5660 char *kaddr;
5661
5662 WARN_ON(!PageUptodate(eb->pages[0]));
5663 kaddr = page_address(eb->pages[0]);
5664 memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,
5665 BTRFS_FSID_SIZE);
5666}
5667
5668void write_extent_buffer_fsid(struct extent_buffer *eb, const void *srcv)
5669{
5670 char *kaddr;
5671
5672 WARN_ON(!PageUptodate(eb->pages[0]));
5673 kaddr = page_address(eb->pages[0]);
5674 memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,
5675 BTRFS_FSID_SIZE);
5676}
5677
5678void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
5679 unsigned long start, unsigned long len)
5680{
5681 size_t cur;
5682 size_t offset;
5683 struct page *page;
5684 char *kaddr;
5685 char *src = (char *)srcv;
5686 size_t start_offset = offset_in_page(eb->start);
5687 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5688
5689 WARN_ON(start > eb->len);
5690 WARN_ON(start + len > eb->start + eb->len);
5691
5692 offset = offset_in_page(start_offset + start);
5693
5694 while (len > 0) {
5695 page = eb->pages[i];
5696 WARN_ON(!PageUptodate(page));
5697
5698 cur = min(len, PAGE_SIZE - offset);
5699 kaddr = page_address(page);
5700 memcpy(kaddr + offset, src, cur);
5701
5702 src += cur;
5703 len -= cur;
5704 offset = 0;
5705 i++;
5706 }
5707}
5708
5709void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
5710 unsigned long len)
5711{
5712 size_t cur;
5713 size_t offset;
5714 struct page *page;
5715 char *kaddr;
5716 size_t start_offset = offset_in_page(eb->start);
5717 unsigned long i = (start_offset + start) >> PAGE_SHIFT;
5718
5719 WARN_ON(start > eb->len);
5720 WARN_ON(start + len > eb->start + eb->len);
5721
5722 offset = offset_in_page(start_offset + start);
5723
5724 while (len > 0) {
5725 page = eb->pages[i];
5726 WARN_ON(!PageUptodate(page));
5727
5728 cur = min(len, PAGE_SIZE - offset);
5729 kaddr = page_address(page);
5730 memset(kaddr + offset, 0, cur);
5731
5732 len -= cur;
5733 offset = 0;
5734 i++;
5735 }
5736}
5737
5738void copy_extent_buffer_full(struct extent_buffer *dst,
5739 struct extent_buffer *src)
5740{
5741 int i;
5742 int num_pages;
5743
5744 ASSERT(dst->len == src->len);
5745
5746 num_pages = num_extent_pages(dst);
5747 for (i = 0; i < num_pages; i++)
5748 copy_page(page_address(dst->pages[i]),
5749 page_address(src->pages[i]));
5750}
5751
5752void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
5753 unsigned long dst_offset, unsigned long src_offset,
5754 unsigned long len)
5755{
5756 u64 dst_len = dst->len;
5757 size_t cur;
5758 size_t offset;
5759 struct page *page;
5760 char *kaddr;
5761 size_t start_offset = offset_in_page(dst->start);
5762 unsigned long i = (start_offset + dst_offset) >> PAGE_SHIFT;
5763
5764 WARN_ON(src->len != dst_len);
5765
5766 offset = offset_in_page(start_offset + dst_offset);
5767
5768 while (len > 0) {
5769 page = dst->pages[i];
5770 WARN_ON(!PageUptodate(page));
5771
5772 cur = min(len, (unsigned long)(PAGE_SIZE - offset));
5773
5774 kaddr = page_address(page);
5775 read_extent_buffer(src, kaddr + offset, src_offset, cur);
5776
5777 src_offset += cur;
5778 len -= cur;
5779 offset = 0;
5780 i++;
5781 }
5782}
5783
5784/*
5785 * eb_bitmap_offset() - calculate the page and offset of the byte containing the
5786 * given bit number
5787 * @eb: the extent buffer
5788 * @start: offset of the bitmap item in the extent buffer
5789 * @nr: bit number
5790 * @page_index: return index of the page in the extent buffer that contains the
5791 * given bit number
5792 * @page_offset: return offset into the page given by page_index
5793 *
5794 * This helper hides the ugliness of finding the byte in an extent buffer which
5795 * contains a given bit.
5796 */
5797static inline void eb_bitmap_offset(struct extent_buffer *eb,
5798 unsigned long start, unsigned long nr,
5799 unsigned long *page_index,
5800 size_t *page_offset)
5801{
5802 size_t start_offset = offset_in_page(eb->start);
5803 size_t byte_offset = BIT_BYTE(nr);
5804 size_t offset;
5805
5806 /*
5807 * The byte we want is the offset of the extent buffer + the offset of
5808 * the bitmap item in the extent buffer + the offset of the byte in the
5809 * bitmap item.
5810 */
5811 offset = start_offset + start + byte_offset;
5812
5813 *page_index = offset >> PAGE_SHIFT;
5814 *page_offset = offset_in_page(offset);
5815}
5816
5817/**
5818 * extent_buffer_test_bit - determine whether a bit in a bitmap item is set
5819 * @eb: the extent buffer
5820 * @start: offset of the bitmap item in the extent buffer
5821 * @nr: bit number to test
5822 */
5823int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
5824 unsigned long nr)
5825{
5826 u8 *kaddr;
5827 struct page *page;
5828 unsigned long i;
5829 size_t offset;
5830
5831 eb_bitmap_offset(eb, start, nr, &i, &offset);
5832 page = eb->pages[i];
5833 WARN_ON(!PageUptodate(page));
5834 kaddr = page_address(page);
5835 return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
5836}
5837
5838/**
5839 * extent_buffer_bitmap_set - set an area of a bitmap
5840 * @eb: the extent buffer
5841 * @start: offset of the bitmap item in the extent buffer
5842 * @pos: bit number of the first bit
5843 * @len: number of bits to set
5844 */
5845void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
5846 unsigned long pos, unsigned long len)
5847{
5848 u8 *kaddr;
5849 struct page *page;
5850 unsigned long i;
5851 size_t offset;
5852 const unsigned int size = pos + len;
5853 int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5854 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
5855
5856 eb_bitmap_offset(eb, start, pos, &i, &offset);
5857 page = eb->pages[i];
5858 WARN_ON(!PageUptodate(page));
5859 kaddr = page_address(page);
5860
5861 while (len >= bits_to_set) {
5862 kaddr[offset] |= mask_to_set;
5863 len -= bits_to_set;
5864 bits_to_set = BITS_PER_BYTE;
5865 mask_to_set = ~0;
5866 if (++offset >= PAGE_SIZE && len > 0) {
5867 offset = 0;
5868 page = eb->pages[++i];
5869 WARN_ON(!PageUptodate(page));
5870 kaddr = page_address(page);
5871 }
5872 }
5873 if (len) {
5874 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
5875 kaddr[offset] |= mask_to_set;
5876 }
5877}
5878
5879
5880/**
5881 * extent_buffer_bitmap_clear - clear an area of a bitmap
5882 * @eb: the extent buffer
5883 * @start: offset of the bitmap item in the extent buffer
5884 * @pos: bit number of the first bit
5885 * @len: number of bits to clear
5886 */
5887void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
5888 unsigned long pos, unsigned long len)
5889{
5890 u8 *kaddr;
5891 struct page *page;
5892 unsigned long i;
5893 size_t offset;
5894 const unsigned int size = pos + len;
5895 int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
5896 u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
5897
5898 eb_bitmap_offset(eb, start, pos, &i, &offset);
5899 page = eb->pages[i];
5900 WARN_ON(!PageUptodate(page));
5901 kaddr = page_address(page);
5902
5903 while (len >= bits_to_clear) {
5904 kaddr[offset] &= ~mask_to_clear;
5905 len -= bits_to_clear;
5906 bits_to_clear = BITS_PER_BYTE;
5907 mask_to_clear = ~0;
5908 if (++offset >= PAGE_SIZE && len > 0) {
5909 offset = 0;
5910 page = eb->pages[++i];
5911 WARN_ON(!PageUptodate(page));
5912 kaddr = page_address(page);
5913 }
5914 }
5915 if (len) {
5916 mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
5917 kaddr[offset] &= ~mask_to_clear;
5918 }
5919}
5920
5921static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
5922{
5923 unsigned long distance = (src > dst) ? src - dst : dst - src;
5924 return distance < len;
5925}
5926
5927static void copy_pages(struct page *dst_page, struct page *src_page,
5928 unsigned long dst_off, unsigned long src_off,
5929 unsigned long len)
5930{
5931 char *dst_kaddr = page_address(dst_page);
5932 char *src_kaddr;
5933 int must_memmove = 0;
5934
5935 if (dst_page != src_page) {
5936 src_kaddr = page_address(src_page);
5937 } else {
5938 src_kaddr = dst_kaddr;
5939 if (areas_overlap(src_off, dst_off, len))
5940 must_memmove = 1;
5941 }
5942
5943 if (must_memmove)
5944 memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
5945 else
5946 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5947}
5948
5949void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5950 unsigned long src_offset, unsigned long len)
5951{
5952 struct btrfs_fs_info *fs_info = dst->fs_info;
5953 size_t cur;
5954 size_t dst_off_in_page;
5955 size_t src_off_in_page;
5956 size_t start_offset = offset_in_page(dst->start);
5957 unsigned long dst_i;
5958 unsigned long src_i;
5959
5960 if (src_offset + len > dst->len) {
5961 btrfs_err(fs_info,
5962 "memmove bogus src_offset %lu move len %lu dst len %lu",
5963 src_offset, len, dst->len);
5964 BUG();
5965 }
5966 if (dst_offset + len > dst->len) {
5967 btrfs_err(fs_info,
5968 "memmove bogus dst_offset %lu move len %lu dst len %lu",
5969 dst_offset, len, dst->len);
5970 BUG();
5971 }
5972
5973 while (len > 0) {
5974 dst_off_in_page = offset_in_page(start_offset + dst_offset);
5975 src_off_in_page = offset_in_page(start_offset + src_offset);
5976
5977 dst_i = (start_offset + dst_offset) >> PAGE_SHIFT;
5978 src_i = (start_offset + src_offset) >> PAGE_SHIFT;
5979
5980 cur = min(len, (unsigned long)(PAGE_SIZE -
5981 src_off_in_page));
5982 cur = min_t(unsigned long, cur,
5983 (unsigned long)(PAGE_SIZE - dst_off_in_page));
5984
5985 copy_pages(dst->pages[dst_i], dst->pages[src_i],
5986 dst_off_in_page, src_off_in_page, cur);
5987
5988 src_offset += cur;
5989 dst_offset += cur;
5990 len -= cur;
5991 }
5992}
5993
5994void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
5995 unsigned long src_offset, unsigned long len)
5996{
5997 struct btrfs_fs_info *fs_info = dst->fs_info;
5998 size_t cur;
5999 size_t dst_off_in_page;
6000 size_t src_off_in_page;
6001 unsigned long dst_end = dst_offset + len - 1;
6002 unsigned long src_end = src_offset + len - 1;
6003 size_t start_offset = offset_in_page(dst->start);
6004 unsigned long dst_i;
6005 unsigned long src_i;
6006
6007 if (src_offset + len > dst->len) {
6008 btrfs_err(fs_info,
6009 "memmove bogus src_offset %lu move len %lu len %lu",
6010 src_offset, len, dst->len);
6011 BUG();
6012 }
6013 if (dst_offset + len > dst->len) {
6014 btrfs_err(fs_info,
6015 "memmove bogus dst_offset %lu move len %lu len %lu",
6016 dst_offset, len, dst->len);
6017 BUG();
6018 }
6019 if (dst_offset < src_offset) {
6020 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
6021 return;
6022 }
6023 while (len > 0) {
6024 dst_i = (start_offset + dst_end) >> PAGE_SHIFT;
6025 src_i = (start_offset + src_end) >> PAGE_SHIFT;
6026
6027 dst_off_in_page = offset_in_page(start_offset + dst_end);
6028 src_off_in_page = offset_in_page(start_offset + src_end);
6029
6030 cur = min_t(unsigned long, len, src_off_in_page + 1);
6031 cur = min(cur, dst_off_in_page + 1);
6032 copy_pages(dst->pages[dst_i], dst->pages[src_i],
6033 dst_off_in_page - cur + 1,
6034 src_off_in_page - cur + 1, cur);
6035
6036 dst_end -= cur;
6037 src_end -= cur;
6038 len -= cur;
6039 }
6040}
6041
6042int try_release_extent_buffer(struct page *page)
6043{
6044 struct extent_buffer *eb;
6045
6046 /*
6047 * We need to make sure nobody is attaching this page to an eb right
6048 * now.
6049 */
6050 spin_lock(&page->mapping->private_lock);
6051 if (!PagePrivate(page)) {
6052 spin_unlock(&page->mapping->private_lock);
6053 return 1;
6054 }
6055
6056 eb = (struct extent_buffer *)page->private;
6057 BUG_ON(!eb);
6058
6059 /*
6060 * This is a little awful but should be ok, we need to make sure that
6061 * the eb doesn't disappear out from under us while we're looking at
6062 * this page.
6063 */
6064 spin_lock(&eb->refs_lock);
6065 if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
6066 spin_unlock(&eb->refs_lock);
6067 spin_unlock(&page->mapping->private_lock);
6068 return 0;
6069 }
6070 spin_unlock(&page->mapping->private_lock);
6071
6072 /*
6073 * If tree ref isn't set then we know the ref on this eb is a real ref,
6074 * so just return, this page will likely be freed soon anyway.
6075 */
6076 if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
6077 spin_unlock(&eb->refs_lock);
6078 return 0;
6079 }
6080
6081 return release_extent_buffer(eb);
6082}
1#include <linux/bitops.h>
2#include <linux/slab.h>
3#include <linux/bio.h>
4#include <linux/mm.h>
5#include <linux/pagemap.h>
6#include <linux/page-flags.h>
7#include <linux/module.h>
8#include <linux/spinlock.h>
9#include <linux/blkdev.h>
10#include <linux/swap.h>
11#include <linux/writeback.h>
12#include <linux/pagevec.h>
13#include <linux/prefetch.h>
14#include <linux/cleancache.h>
15#include "extent_io.h"
16#include "extent_map.h"
17#include "compat.h"
18#include "ctree.h"
19#include "btrfs_inode.h"
20
21static struct kmem_cache *extent_state_cache;
22static struct kmem_cache *extent_buffer_cache;
23
24static LIST_HEAD(buffers);
25static LIST_HEAD(states);
26
27#define LEAK_DEBUG 0
28#if LEAK_DEBUG
29static DEFINE_SPINLOCK(leak_lock);
30#endif
31
32#define BUFFER_LRU_MAX 64
33
34struct tree_entry {
35 u64 start;
36 u64 end;
37 struct rb_node rb_node;
38};
39
40struct extent_page_data {
41 struct bio *bio;
42 struct extent_io_tree *tree;
43 get_extent_t *get_extent;
44
45 /* tells writepage not to lock the state bits for this range
46 * it still does the unlocking
47 */
48 unsigned int extent_locked:1;
49
50 /* tells the submit_bio code to use a WRITE_SYNC */
51 unsigned int sync_io:1;
52};
53
54int __init extent_io_init(void)
55{
56 extent_state_cache = kmem_cache_create("extent_state",
57 sizeof(struct extent_state), 0,
58 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
59 if (!extent_state_cache)
60 return -ENOMEM;
61
62 extent_buffer_cache = kmem_cache_create("extent_buffers",
63 sizeof(struct extent_buffer), 0,
64 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
65 if (!extent_buffer_cache)
66 goto free_state_cache;
67 return 0;
68
69free_state_cache:
70 kmem_cache_destroy(extent_state_cache);
71 return -ENOMEM;
72}
73
74void extent_io_exit(void)
75{
76 struct extent_state *state;
77 struct extent_buffer *eb;
78
79 while (!list_empty(&states)) {
80 state = list_entry(states.next, struct extent_state, leak_list);
81 printk(KERN_ERR "btrfs state leak: start %llu end %llu "
82 "state %lu in tree %p refs %d\n",
83 (unsigned long long)state->start,
84 (unsigned long long)state->end,
85 state->state, state->tree, atomic_read(&state->refs));
86 list_del(&state->leak_list);
87 kmem_cache_free(extent_state_cache, state);
88
89 }
90
91 while (!list_empty(&buffers)) {
92 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
93 printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
94 "refs %d\n", (unsigned long long)eb->start,
95 eb->len, atomic_read(&eb->refs));
96 list_del(&eb->leak_list);
97 kmem_cache_free(extent_buffer_cache, eb);
98 }
99 if (extent_state_cache)
100 kmem_cache_destroy(extent_state_cache);
101 if (extent_buffer_cache)
102 kmem_cache_destroy(extent_buffer_cache);
103}
104
105void extent_io_tree_init(struct extent_io_tree *tree,
106 struct address_space *mapping)
107{
108 tree->state = RB_ROOT;
109 INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
110 tree->ops = NULL;
111 tree->dirty_bytes = 0;
112 spin_lock_init(&tree->lock);
113 spin_lock_init(&tree->buffer_lock);
114 tree->mapping = mapping;
115}
116
117static struct extent_state *alloc_extent_state(gfp_t mask)
118{
119 struct extent_state *state;
120#if LEAK_DEBUG
121 unsigned long flags;
122#endif
123
124 state = kmem_cache_alloc(extent_state_cache, mask);
125 if (!state)
126 return state;
127 state->state = 0;
128 state->private = 0;
129 state->tree = NULL;
130#if LEAK_DEBUG
131 spin_lock_irqsave(&leak_lock, flags);
132 list_add(&state->leak_list, &states);
133 spin_unlock_irqrestore(&leak_lock, flags);
134#endif
135 atomic_set(&state->refs, 1);
136 init_waitqueue_head(&state->wq);
137 return state;
138}
139
140void free_extent_state(struct extent_state *state)
141{
142 if (!state)
143 return;
144 if (atomic_dec_and_test(&state->refs)) {
145#if LEAK_DEBUG
146 unsigned long flags;
147#endif
148 WARN_ON(state->tree);
149#if LEAK_DEBUG
150 spin_lock_irqsave(&leak_lock, flags);
151 list_del(&state->leak_list);
152 spin_unlock_irqrestore(&leak_lock, flags);
153#endif
154 kmem_cache_free(extent_state_cache, state);
155 }
156}
157
158static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
159 struct rb_node *node)
160{
161 struct rb_node **p = &root->rb_node;
162 struct rb_node *parent = NULL;
163 struct tree_entry *entry;
164
165 while (*p) {
166 parent = *p;
167 entry = rb_entry(parent, struct tree_entry, rb_node);
168
169 if (offset < entry->start)
170 p = &(*p)->rb_left;
171 else if (offset > entry->end)
172 p = &(*p)->rb_right;
173 else
174 return parent;
175 }
176
177 entry = rb_entry(node, struct tree_entry, rb_node);
178 rb_link_node(node, parent, p);
179 rb_insert_color(node, root);
180 return NULL;
181}
182
183static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
184 struct rb_node **prev_ret,
185 struct rb_node **next_ret)
186{
187 struct rb_root *root = &tree->state;
188 struct rb_node *n = root->rb_node;
189 struct rb_node *prev = NULL;
190 struct rb_node *orig_prev = NULL;
191 struct tree_entry *entry;
192 struct tree_entry *prev_entry = NULL;
193
194 while (n) {
195 entry = rb_entry(n, struct tree_entry, rb_node);
196 prev = n;
197 prev_entry = entry;
198
199 if (offset < entry->start)
200 n = n->rb_left;
201 else if (offset > entry->end)
202 n = n->rb_right;
203 else
204 return n;
205 }
206
207 if (prev_ret) {
208 orig_prev = prev;
209 while (prev && offset > prev_entry->end) {
210 prev = rb_next(prev);
211 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
212 }
213 *prev_ret = prev;
214 prev = orig_prev;
215 }
216
217 if (next_ret) {
218 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
219 while (prev && offset < prev_entry->start) {
220 prev = rb_prev(prev);
221 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
222 }
223 *next_ret = prev;
224 }
225 return NULL;
226}
227
228static inline struct rb_node *tree_search(struct extent_io_tree *tree,
229 u64 offset)
230{
231 struct rb_node *prev = NULL;
232 struct rb_node *ret;
233
234 ret = __etree_search(tree, offset, &prev, NULL);
235 if (!ret)
236 return prev;
237 return ret;
238}
239
240static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
241 struct extent_state *other)
242{
243 if (tree->ops && tree->ops->merge_extent_hook)
244 tree->ops->merge_extent_hook(tree->mapping->host, new,
245 other);
246}
247
248/*
249 * utility function to look for merge candidates inside a given range.
250 * Any extents with matching state are merged together into a single
251 * extent in the tree. Extents with EXTENT_IO in their state field
252 * are not merged because the end_io handlers need to be able to do
253 * operations on them without sleeping (or doing allocations/splits).
254 *
255 * This should be called with the tree lock held.
256 */
257static void merge_state(struct extent_io_tree *tree,
258 struct extent_state *state)
259{
260 struct extent_state *other;
261 struct rb_node *other_node;
262
263 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
264 return;
265
266 other_node = rb_prev(&state->rb_node);
267 if (other_node) {
268 other = rb_entry(other_node, struct extent_state, rb_node);
269 if (other->end == state->start - 1 &&
270 other->state == state->state) {
271 merge_cb(tree, state, other);
272 state->start = other->start;
273 other->tree = NULL;
274 rb_erase(&other->rb_node, &tree->state);
275 free_extent_state(other);
276 }
277 }
278 other_node = rb_next(&state->rb_node);
279 if (other_node) {
280 other = rb_entry(other_node, struct extent_state, rb_node);
281 if (other->start == state->end + 1 &&
282 other->state == state->state) {
283 merge_cb(tree, state, other);
284 state->end = other->end;
285 other->tree = NULL;
286 rb_erase(&other->rb_node, &tree->state);
287 free_extent_state(other);
288 }
289 }
290}
291
292static void set_state_cb(struct extent_io_tree *tree,
293 struct extent_state *state, int *bits)
294{
295 if (tree->ops && tree->ops->set_bit_hook)
296 tree->ops->set_bit_hook(tree->mapping->host, state, bits);
297}
298
299static void clear_state_cb(struct extent_io_tree *tree,
300 struct extent_state *state, int *bits)
301{
302 if (tree->ops && tree->ops->clear_bit_hook)
303 tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
304}
305
306static void set_state_bits(struct extent_io_tree *tree,
307 struct extent_state *state, int *bits);
308
309/*
310 * insert an extent_state struct into the tree. 'bits' are set on the
311 * struct before it is inserted.
312 *
313 * This may return -EEXIST if the extent is already there, in which case the
314 * state struct is freed.
315 *
316 * The tree lock is not taken internally. This is a utility function and
317 * probably isn't what you want to call (see set/clear_extent_bit).
318 */
319static int insert_state(struct extent_io_tree *tree,
320 struct extent_state *state, u64 start, u64 end,
321 int *bits)
322{
323 struct rb_node *node;
324
325 if (end < start) {
326 printk(KERN_ERR "btrfs end < start %llu %llu\n",
327 (unsigned long long)end,
328 (unsigned long long)start);
329 WARN_ON(1);
330 }
331 state->start = start;
332 state->end = end;
333
334 set_state_bits(tree, state, bits);
335
336 node = tree_insert(&tree->state, end, &state->rb_node);
337 if (node) {
338 struct extent_state *found;
339 found = rb_entry(node, struct extent_state, rb_node);
340 printk(KERN_ERR "btrfs found node %llu %llu on insert of "
341 "%llu %llu\n", (unsigned long long)found->start,
342 (unsigned long long)found->end,
343 (unsigned long long)start, (unsigned long long)end);
344 return -EEXIST;
345 }
346 state->tree = tree;
347 merge_state(tree, state);
348 return 0;
349}
350
351static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
352 u64 split)
353{
354 if (tree->ops && tree->ops->split_extent_hook)
355 tree->ops->split_extent_hook(tree->mapping->host, orig, split);
356}
357
358/*
359 * split a given extent state struct in two, inserting the preallocated
360 * struct 'prealloc' as the newly created second half. 'split' indicates an
361 * offset inside 'orig' where it should be split.
362 *
363 * Before calling,
364 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
365 * are two extent state structs in the tree:
366 * prealloc: [orig->start, split - 1]
367 * orig: [ split, orig->end ]
368 *
369 * The tree locks are not taken by this function. They need to be held
370 * by the caller.
371 */
372static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
373 struct extent_state *prealloc, u64 split)
374{
375 struct rb_node *node;
376
377 split_cb(tree, orig, split);
378
379 prealloc->start = orig->start;
380 prealloc->end = split - 1;
381 prealloc->state = orig->state;
382 orig->start = split;
383
384 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
385 if (node) {
386 free_extent_state(prealloc);
387 return -EEXIST;
388 }
389 prealloc->tree = tree;
390 return 0;
391}
392
393/*
394 * utility function to clear some bits in an extent state struct.
395 * it will optionally wake up any one waiting on this state (wake == 1), or
396 * forcibly remove the state from the tree (delete == 1).
397 *
398 * If no bits are set on the state struct after clearing things, the
399 * struct is freed and removed from the tree
400 */
401static int clear_state_bit(struct extent_io_tree *tree,
402 struct extent_state *state,
403 int *bits, int wake)
404{
405 int bits_to_clear = *bits & ~EXTENT_CTLBITS;
406 int ret = state->state & bits_to_clear;
407
408 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
409 u64 range = state->end - state->start + 1;
410 WARN_ON(range > tree->dirty_bytes);
411 tree->dirty_bytes -= range;
412 }
413 clear_state_cb(tree, state, bits);
414 state->state &= ~bits_to_clear;
415 if (wake)
416 wake_up(&state->wq);
417 if (state->state == 0) {
418 if (state->tree) {
419 rb_erase(&state->rb_node, &tree->state);
420 state->tree = NULL;
421 free_extent_state(state);
422 } else {
423 WARN_ON(1);
424 }
425 } else {
426 merge_state(tree, state);
427 }
428 return ret;
429}
430
431static struct extent_state *
432alloc_extent_state_atomic(struct extent_state *prealloc)
433{
434 if (!prealloc)
435 prealloc = alloc_extent_state(GFP_ATOMIC);
436
437 return prealloc;
438}
439
440/*
441 * clear some bits on a range in the tree. This may require splitting
442 * or inserting elements in the tree, so the gfp mask is used to
443 * indicate which allocations or sleeping are allowed.
444 *
445 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
446 * the given range from the tree regardless of state (ie for truncate).
447 *
448 * the range [start, end] is inclusive.
449 *
450 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
451 * bits were already set, or zero if none of the bits were already set.
452 */
453int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
454 int bits, int wake, int delete,
455 struct extent_state **cached_state,
456 gfp_t mask)
457{
458 struct extent_state *state;
459 struct extent_state *cached;
460 struct extent_state *prealloc = NULL;
461 struct rb_node *next_node;
462 struct rb_node *node;
463 u64 last_end;
464 int err;
465 int set = 0;
466 int clear = 0;
467
468 if (delete)
469 bits |= ~EXTENT_CTLBITS;
470 bits |= EXTENT_FIRST_DELALLOC;
471
472 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
473 clear = 1;
474again:
475 if (!prealloc && (mask & __GFP_WAIT)) {
476 prealloc = alloc_extent_state(mask);
477 if (!prealloc)
478 return -ENOMEM;
479 }
480
481 spin_lock(&tree->lock);
482 if (cached_state) {
483 cached = *cached_state;
484
485 if (clear) {
486 *cached_state = NULL;
487 cached_state = NULL;
488 }
489
490 if (cached && cached->tree && cached->start <= start &&
491 cached->end > start) {
492 if (clear)
493 atomic_dec(&cached->refs);
494 state = cached;
495 goto hit_next;
496 }
497 if (clear)
498 free_extent_state(cached);
499 }
500 /*
501 * this search will find the extents that end after
502 * our range starts
503 */
504 node = tree_search(tree, start);
505 if (!node)
506 goto out;
507 state = rb_entry(node, struct extent_state, rb_node);
508hit_next:
509 if (state->start > end)
510 goto out;
511 WARN_ON(state->end < start);
512 last_end = state->end;
513
514 /*
515 * | ---- desired range ---- |
516 * | state | or
517 * | ------------- state -------------- |
518 *
519 * We need to split the extent we found, and may flip
520 * bits on second half.
521 *
522 * If the extent we found extends past our range, we
523 * just split and search again. It'll get split again
524 * the next time though.
525 *
526 * If the extent we found is inside our range, we clear
527 * the desired bit on it.
528 */
529
530 if (state->start < start) {
531 prealloc = alloc_extent_state_atomic(prealloc);
532 BUG_ON(!prealloc);
533 err = split_state(tree, state, prealloc, start);
534 BUG_ON(err == -EEXIST);
535 prealloc = NULL;
536 if (err)
537 goto out;
538 if (state->end <= end) {
539 set |= clear_state_bit(tree, state, &bits, wake);
540 if (last_end == (u64)-1)
541 goto out;
542 start = last_end + 1;
543 }
544 goto search_again;
545 }
546 /*
547 * | ---- desired range ---- |
548 * | state |
549 * We need to split the extent, and clear the bit
550 * on the first half
551 */
552 if (state->start <= end && state->end > end) {
553 prealloc = alloc_extent_state_atomic(prealloc);
554 BUG_ON(!prealloc);
555 err = split_state(tree, state, prealloc, end + 1);
556 BUG_ON(err == -EEXIST);
557 if (wake)
558 wake_up(&state->wq);
559
560 set |= clear_state_bit(tree, prealloc, &bits, wake);
561
562 prealloc = NULL;
563 goto out;
564 }
565
566 if (state->end < end && prealloc && !need_resched())
567 next_node = rb_next(&state->rb_node);
568 else
569 next_node = NULL;
570
571 set |= clear_state_bit(tree, state, &bits, wake);
572 if (last_end == (u64)-1)
573 goto out;
574 start = last_end + 1;
575 if (start <= end && next_node) {
576 state = rb_entry(next_node, struct extent_state,
577 rb_node);
578 if (state->start == start)
579 goto hit_next;
580 }
581 goto search_again;
582
583out:
584 spin_unlock(&tree->lock);
585 if (prealloc)
586 free_extent_state(prealloc);
587
588 return set;
589
590search_again:
591 if (start > end)
592 goto out;
593 spin_unlock(&tree->lock);
594 if (mask & __GFP_WAIT)
595 cond_resched();
596 goto again;
597}
598
599static int wait_on_state(struct extent_io_tree *tree,
600 struct extent_state *state)
601 __releases(tree->lock)
602 __acquires(tree->lock)
603{
604 DEFINE_WAIT(wait);
605 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
606 spin_unlock(&tree->lock);
607 schedule();
608 spin_lock(&tree->lock);
609 finish_wait(&state->wq, &wait);
610 return 0;
611}
612
613/*
614 * waits for one or more bits to clear on a range in the state tree.
615 * The range [start, end] is inclusive.
616 * The tree lock is taken by this function
617 */
618int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
619{
620 struct extent_state *state;
621 struct rb_node *node;
622
623 spin_lock(&tree->lock);
624again:
625 while (1) {
626 /*
627 * this search will find all the extents that end after
628 * our range starts
629 */
630 node = tree_search(tree, start);
631 if (!node)
632 break;
633
634 state = rb_entry(node, struct extent_state, rb_node);
635
636 if (state->start > end)
637 goto out;
638
639 if (state->state & bits) {
640 start = state->start;
641 atomic_inc(&state->refs);
642 wait_on_state(tree, state);
643 free_extent_state(state);
644 goto again;
645 }
646 start = state->end + 1;
647
648 if (start > end)
649 break;
650
651 cond_resched_lock(&tree->lock);
652 }
653out:
654 spin_unlock(&tree->lock);
655 return 0;
656}
657
658static void set_state_bits(struct extent_io_tree *tree,
659 struct extent_state *state,
660 int *bits)
661{
662 int bits_to_set = *bits & ~EXTENT_CTLBITS;
663
664 set_state_cb(tree, state, bits);
665 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
666 u64 range = state->end - state->start + 1;
667 tree->dirty_bytes += range;
668 }
669 state->state |= bits_to_set;
670}
671
672static void cache_state(struct extent_state *state,
673 struct extent_state **cached_ptr)
674{
675 if (cached_ptr && !(*cached_ptr)) {
676 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
677 *cached_ptr = state;
678 atomic_inc(&state->refs);
679 }
680 }
681}
682
683static void uncache_state(struct extent_state **cached_ptr)
684{
685 if (cached_ptr && (*cached_ptr)) {
686 struct extent_state *state = *cached_ptr;
687 *cached_ptr = NULL;
688 free_extent_state(state);
689 }
690}
691
692/*
693 * set some bits on a range in the tree. This may require allocations or
694 * sleeping, so the gfp mask is used to indicate what is allowed.
695 *
696 * If any of the exclusive bits are set, this will fail with -EEXIST if some
697 * part of the range already has the desired bits set. The start of the
698 * existing range is returned in failed_start in this case.
699 *
700 * [start, end] is inclusive This takes the tree lock.
701 */
702
703int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
704 int bits, int exclusive_bits, u64 *failed_start,
705 struct extent_state **cached_state, gfp_t mask)
706{
707 struct extent_state *state;
708 struct extent_state *prealloc = NULL;
709 struct rb_node *node;
710 int err = 0;
711 u64 last_start;
712 u64 last_end;
713
714 bits |= EXTENT_FIRST_DELALLOC;
715again:
716 if (!prealloc && (mask & __GFP_WAIT)) {
717 prealloc = alloc_extent_state(mask);
718 BUG_ON(!prealloc);
719 }
720
721 spin_lock(&tree->lock);
722 if (cached_state && *cached_state) {
723 state = *cached_state;
724 if (state->start <= start && state->end > start &&
725 state->tree) {
726 node = &state->rb_node;
727 goto hit_next;
728 }
729 }
730 /*
731 * this search will find all the extents that end after
732 * our range starts.
733 */
734 node = tree_search(tree, start);
735 if (!node) {
736 prealloc = alloc_extent_state_atomic(prealloc);
737 BUG_ON(!prealloc);
738 err = insert_state(tree, prealloc, start, end, &bits);
739 prealloc = NULL;
740 BUG_ON(err == -EEXIST);
741 goto out;
742 }
743 state = rb_entry(node, struct extent_state, rb_node);
744hit_next:
745 last_start = state->start;
746 last_end = state->end;
747
748 /*
749 * | ---- desired range ---- |
750 * | state |
751 *
752 * Just lock what we found and keep going
753 */
754 if (state->start == start && state->end <= end) {
755 struct rb_node *next_node;
756 if (state->state & exclusive_bits) {
757 *failed_start = state->start;
758 err = -EEXIST;
759 goto out;
760 }
761
762 set_state_bits(tree, state, &bits);
763
764 cache_state(state, cached_state);
765 merge_state(tree, state);
766 if (last_end == (u64)-1)
767 goto out;
768
769 start = last_end + 1;
770 next_node = rb_next(&state->rb_node);
771 if (next_node && start < end && prealloc && !need_resched()) {
772 state = rb_entry(next_node, struct extent_state,
773 rb_node);
774 if (state->start == start)
775 goto hit_next;
776 }
777 goto search_again;
778 }
779
780 /*
781 * | ---- desired range ---- |
782 * | state |
783 * or
784 * | ------------- state -------------- |
785 *
786 * We need to split the extent we found, and may flip bits on
787 * second half.
788 *
789 * If the extent we found extends past our
790 * range, we just split and search again. It'll get split
791 * again the next time though.
792 *
793 * If the extent we found is inside our range, we set the
794 * desired bit on it.
795 */
796 if (state->start < start) {
797 if (state->state & exclusive_bits) {
798 *failed_start = start;
799 err = -EEXIST;
800 goto out;
801 }
802
803 prealloc = alloc_extent_state_atomic(prealloc);
804 BUG_ON(!prealloc);
805 err = split_state(tree, state, prealloc, start);
806 BUG_ON(err == -EEXIST);
807 prealloc = NULL;
808 if (err)
809 goto out;
810 if (state->end <= end) {
811 set_state_bits(tree, state, &bits);
812 cache_state(state, cached_state);
813 merge_state(tree, state);
814 if (last_end == (u64)-1)
815 goto out;
816 start = last_end + 1;
817 }
818 goto search_again;
819 }
820 /*
821 * | ---- desired range ---- |
822 * | state | or | state |
823 *
824 * There's a hole, we need to insert something in it and
825 * ignore the extent we found.
826 */
827 if (state->start > start) {
828 u64 this_end;
829 if (end < last_start)
830 this_end = end;
831 else
832 this_end = last_start - 1;
833
834 prealloc = alloc_extent_state_atomic(prealloc);
835 BUG_ON(!prealloc);
836
837 /*
838 * Avoid to free 'prealloc' if it can be merged with
839 * the later extent.
840 */
841 err = insert_state(tree, prealloc, start, this_end,
842 &bits);
843 BUG_ON(err == -EEXIST);
844 if (err) {
845 free_extent_state(prealloc);
846 prealloc = NULL;
847 goto out;
848 }
849 cache_state(prealloc, cached_state);
850 prealloc = NULL;
851 start = this_end + 1;
852 goto search_again;
853 }
854 /*
855 * | ---- desired range ---- |
856 * | state |
857 * We need to split the extent, and set the bit
858 * on the first half
859 */
860 if (state->start <= end && state->end > end) {
861 if (state->state & exclusive_bits) {
862 *failed_start = start;
863 err = -EEXIST;
864 goto out;
865 }
866
867 prealloc = alloc_extent_state_atomic(prealloc);
868 BUG_ON(!prealloc);
869 err = split_state(tree, state, prealloc, end + 1);
870 BUG_ON(err == -EEXIST);
871
872 set_state_bits(tree, prealloc, &bits);
873 cache_state(prealloc, cached_state);
874 merge_state(tree, prealloc);
875 prealloc = NULL;
876 goto out;
877 }
878
879 goto search_again;
880
881out:
882 spin_unlock(&tree->lock);
883 if (prealloc)
884 free_extent_state(prealloc);
885
886 return err;
887
888search_again:
889 if (start > end)
890 goto out;
891 spin_unlock(&tree->lock);
892 if (mask & __GFP_WAIT)
893 cond_resched();
894 goto again;
895}
896
897/* wrappers around set/clear extent bit */
898int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
899 gfp_t mask)
900{
901 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
902 NULL, mask);
903}
904
905int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
906 int bits, gfp_t mask)
907{
908 return set_extent_bit(tree, start, end, bits, 0, NULL,
909 NULL, mask);
910}
911
912int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
913 int bits, gfp_t mask)
914{
915 return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
916}
917
918int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
919 struct extent_state **cached_state, gfp_t mask)
920{
921 return set_extent_bit(tree, start, end,
922 EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
923 0, NULL, cached_state, mask);
924}
925
926int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
927 gfp_t mask)
928{
929 return clear_extent_bit(tree, start, end,
930 EXTENT_DIRTY | EXTENT_DELALLOC |
931 EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
932}
933
934int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
935 gfp_t mask)
936{
937 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
938 NULL, mask);
939}
940
941int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
942 struct extent_state **cached_state, gfp_t mask)
943{
944 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0,
945 NULL, cached_state, mask);
946}
947
948static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
949 u64 end, struct extent_state **cached_state,
950 gfp_t mask)
951{
952 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
953 cached_state, mask);
954}
955
956/*
957 * either insert or lock state struct between start and end use mask to tell
958 * us if waiting is desired.
959 */
960int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
961 int bits, struct extent_state **cached_state, gfp_t mask)
962{
963 int err;
964 u64 failed_start;
965 while (1) {
966 err = set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
967 EXTENT_LOCKED, &failed_start,
968 cached_state, mask);
969 if (err == -EEXIST && (mask & __GFP_WAIT)) {
970 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
971 start = failed_start;
972 } else {
973 break;
974 }
975 WARN_ON(start > end);
976 }
977 return err;
978}
979
980int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
981{
982 return lock_extent_bits(tree, start, end, 0, NULL, mask);
983}
984
985int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
986 gfp_t mask)
987{
988 int err;
989 u64 failed_start;
990
991 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
992 &failed_start, NULL, mask);
993 if (err == -EEXIST) {
994 if (failed_start > start)
995 clear_extent_bit(tree, start, failed_start - 1,
996 EXTENT_LOCKED, 1, 0, NULL, mask);
997 return 0;
998 }
999 return 1;
1000}
1001
1002int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
1003 struct extent_state **cached, gfp_t mask)
1004{
1005 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
1006 mask);
1007}
1008
1009int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
1010{
1011 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1012 mask);
1013}
1014
1015/*
1016 * helper function to set both pages and extents in the tree writeback
1017 */
1018static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1019{
1020 unsigned long index = start >> PAGE_CACHE_SHIFT;
1021 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1022 struct page *page;
1023
1024 while (index <= end_index) {
1025 page = find_get_page(tree->mapping, index);
1026 BUG_ON(!page);
1027 set_page_writeback(page);
1028 page_cache_release(page);
1029 index++;
1030 }
1031 return 0;
1032}
1033
1034/* find the first state struct with 'bits' set after 'start', and
1035 * return it. tree->lock must be held. NULL will returned if
1036 * nothing was found after 'start'
1037 */
1038struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
1039 u64 start, int bits)
1040{
1041 struct rb_node *node;
1042 struct extent_state *state;
1043
1044 /*
1045 * this search will find all the extents that end after
1046 * our range starts.
1047 */
1048 node = tree_search(tree, start);
1049 if (!node)
1050 goto out;
1051
1052 while (1) {
1053 state = rb_entry(node, struct extent_state, rb_node);
1054 if (state->end >= start && (state->state & bits))
1055 return state;
1056
1057 node = rb_next(node);
1058 if (!node)
1059 break;
1060 }
1061out:
1062 return NULL;
1063}
1064
1065/*
1066 * find the first offset in the io tree with 'bits' set. zero is
1067 * returned if we find something, and *start_ret and *end_ret are
1068 * set to reflect the state struct that was found.
1069 *
1070 * If nothing was found, 1 is returned, < 0 on error
1071 */
1072int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1073 u64 *start_ret, u64 *end_ret, int bits)
1074{
1075 struct extent_state *state;
1076 int ret = 1;
1077
1078 spin_lock(&tree->lock);
1079 state = find_first_extent_bit_state(tree, start, bits);
1080 if (state) {
1081 *start_ret = state->start;
1082 *end_ret = state->end;
1083 ret = 0;
1084 }
1085 spin_unlock(&tree->lock);
1086 return ret;
1087}
1088
1089/*
1090 * find a contiguous range of bytes in the file marked as delalloc, not
1091 * more than 'max_bytes'. start and end are used to return the range,
1092 *
1093 * 1 is returned if we find something, 0 if nothing was in the tree
1094 */
1095static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1096 u64 *start, u64 *end, u64 max_bytes,
1097 struct extent_state **cached_state)
1098{
1099 struct rb_node *node;
1100 struct extent_state *state;
1101 u64 cur_start = *start;
1102 u64 found = 0;
1103 u64 total_bytes = 0;
1104
1105 spin_lock(&tree->lock);
1106
1107 /*
1108 * this search will find all the extents that end after
1109 * our range starts.
1110 */
1111 node = tree_search(tree, cur_start);
1112 if (!node) {
1113 if (!found)
1114 *end = (u64)-1;
1115 goto out;
1116 }
1117
1118 while (1) {
1119 state = rb_entry(node, struct extent_state, rb_node);
1120 if (found && (state->start != cur_start ||
1121 (state->state & EXTENT_BOUNDARY))) {
1122 goto out;
1123 }
1124 if (!(state->state & EXTENT_DELALLOC)) {
1125 if (!found)
1126 *end = state->end;
1127 goto out;
1128 }
1129 if (!found) {
1130 *start = state->start;
1131 *cached_state = state;
1132 atomic_inc(&state->refs);
1133 }
1134 found++;
1135 *end = state->end;
1136 cur_start = state->end + 1;
1137 node = rb_next(node);
1138 if (!node)
1139 break;
1140 total_bytes += state->end - state->start + 1;
1141 if (total_bytes >= max_bytes)
1142 break;
1143 }
1144out:
1145 spin_unlock(&tree->lock);
1146 return found;
1147}
1148
1149static noinline int __unlock_for_delalloc(struct inode *inode,
1150 struct page *locked_page,
1151 u64 start, u64 end)
1152{
1153 int ret;
1154 struct page *pages[16];
1155 unsigned long index = start >> PAGE_CACHE_SHIFT;
1156 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1157 unsigned long nr_pages = end_index - index + 1;
1158 int i;
1159
1160 if (index == locked_page->index && end_index == index)
1161 return 0;
1162
1163 while (nr_pages > 0) {
1164 ret = find_get_pages_contig(inode->i_mapping, index,
1165 min_t(unsigned long, nr_pages,
1166 ARRAY_SIZE(pages)), pages);
1167 for (i = 0; i < ret; i++) {
1168 if (pages[i] != locked_page)
1169 unlock_page(pages[i]);
1170 page_cache_release(pages[i]);
1171 }
1172 nr_pages -= ret;
1173 index += ret;
1174 cond_resched();
1175 }
1176 return 0;
1177}
1178
1179static noinline int lock_delalloc_pages(struct inode *inode,
1180 struct page *locked_page,
1181 u64 delalloc_start,
1182 u64 delalloc_end)
1183{
1184 unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
1185 unsigned long start_index = index;
1186 unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
1187 unsigned long pages_locked = 0;
1188 struct page *pages[16];
1189 unsigned long nrpages;
1190 int ret;
1191 int i;
1192
1193 /* the caller is responsible for locking the start index */
1194 if (index == locked_page->index && index == end_index)
1195 return 0;
1196
1197 /* skip the page at the start index */
1198 nrpages = end_index - index + 1;
1199 while (nrpages > 0) {
1200 ret = find_get_pages_contig(inode->i_mapping, index,
1201 min_t(unsigned long,
1202 nrpages, ARRAY_SIZE(pages)), pages);
1203 if (ret == 0) {
1204 ret = -EAGAIN;
1205 goto done;
1206 }
1207 /* now we have an array of pages, lock them all */
1208 for (i = 0; i < ret; i++) {
1209 /*
1210 * the caller is taking responsibility for
1211 * locked_page
1212 */
1213 if (pages[i] != locked_page) {
1214 lock_page(pages[i]);
1215 if (!PageDirty(pages[i]) ||
1216 pages[i]->mapping != inode->i_mapping) {
1217 ret = -EAGAIN;
1218 unlock_page(pages[i]);
1219 page_cache_release(pages[i]);
1220 goto done;
1221 }
1222 }
1223 page_cache_release(pages[i]);
1224 pages_locked++;
1225 }
1226 nrpages -= ret;
1227 index += ret;
1228 cond_resched();
1229 }
1230 ret = 0;
1231done:
1232 if (ret && pages_locked) {
1233 __unlock_for_delalloc(inode, locked_page,
1234 delalloc_start,
1235 ((u64)(start_index + pages_locked - 1)) <<
1236 PAGE_CACHE_SHIFT);
1237 }
1238 return ret;
1239}
1240
1241/*
1242 * find a contiguous range of bytes in the file marked as delalloc, not
1243 * more than 'max_bytes'. start and end are used to return the range,
1244 *
1245 * 1 is returned if we find something, 0 if nothing was in the tree
1246 */
1247static noinline u64 find_lock_delalloc_range(struct inode *inode,
1248 struct extent_io_tree *tree,
1249 struct page *locked_page,
1250 u64 *start, u64 *end,
1251 u64 max_bytes)
1252{
1253 u64 delalloc_start;
1254 u64 delalloc_end;
1255 u64 found;
1256 struct extent_state *cached_state = NULL;
1257 int ret;
1258 int loops = 0;
1259
1260again:
1261 /* step one, find a bunch of delalloc bytes starting at start */
1262 delalloc_start = *start;
1263 delalloc_end = 0;
1264 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1265 max_bytes, &cached_state);
1266 if (!found || delalloc_end <= *start) {
1267 *start = delalloc_start;
1268 *end = delalloc_end;
1269 free_extent_state(cached_state);
1270 return found;
1271 }
1272
1273 /*
1274 * start comes from the offset of locked_page. We have to lock
1275 * pages in order, so we can't process delalloc bytes before
1276 * locked_page
1277 */
1278 if (delalloc_start < *start)
1279 delalloc_start = *start;
1280
1281 /*
1282 * make sure to limit the number of pages we try to lock down
1283 * if we're looping.
1284 */
1285 if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1286 delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
1287
1288 /* step two, lock all the pages after the page that has start */
1289 ret = lock_delalloc_pages(inode, locked_page,
1290 delalloc_start, delalloc_end);
1291 if (ret == -EAGAIN) {
1292 /* some of the pages are gone, lets avoid looping by
1293 * shortening the size of the delalloc range we're searching
1294 */
1295 free_extent_state(cached_state);
1296 if (!loops) {
1297 unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
1298 max_bytes = PAGE_CACHE_SIZE - offset;
1299 loops = 1;
1300 goto again;
1301 } else {
1302 found = 0;
1303 goto out_failed;
1304 }
1305 }
1306 BUG_ON(ret);
1307
1308 /* step three, lock the state bits for the whole range */
1309 lock_extent_bits(tree, delalloc_start, delalloc_end,
1310 0, &cached_state, GFP_NOFS);
1311
1312 /* then test to make sure it is all still delalloc */
1313 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1314 EXTENT_DELALLOC, 1, cached_state);
1315 if (!ret) {
1316 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1317 &cached_state, GFP_NOFS);
1318 __unlock_for_delalloc(inode, locked_page,
1319 delalloc_start, delalloc_end);
1320 cond_resched();
1321 goto again;
1322 }
1323 free_extent_state(cached_state);
1324 *start = delalloc_start;
1325 *end = delalloc_end;
1326out_failed:
1327 return found;
1328}
1329
1330int extent_clear_unlock_delalloc(struct inode *inode,
1331 struct extent_io_tree *tree,
1332 u64 start, u64 end, struct page *locked_page,
1333 unsigned long op)
1334{
1335 int ret;
1336 struct page *pages[16];
1337 unsigned long index = start >> PAGE_CACHE_SHIFT;
1338 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1339 unsigned long nr_pages = end_index - index + 1;
1340 int i;
1341 int clear_bits = 0;
1342
1343 if (op & EXTENT_CLEAR_UNLOCK)
1344 clear_bits |= EXTENT_LOCKED;
1345 if (op & EXTENT_CLEAR_DIRTY)
1346 clear_bits |= EXTENT_DIRTY;
1347
1348 if (op & EXTENT_CLEAR_DELALLOC)
1349 clear_bits |= EXTENT_DELALLOC;
1350
1351 clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1352 if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
1353 EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
1354 EXTENT_SET_PRIVATE2)))
1355 return 0;
1356
1357 while (nr_pages > 0) {
1358 ret = find_get_pages_contig(inode->i_mapping, index,
1359 min_t(unsigned long,
1360 nr_pages, ARRAY_SIZE(pages)), pages);
1361 for (i = 0; i < ret; i++) {
1362
1363 if (op & EXTENT_SET_PRIVATE2)
1364 SetPagePrivate2(pages[i]);
1365
1366 if (pages[i] == locked_page) {
1367 page_cache_release(pages[i]);
1368 continue;
1369 }
1370 if (op & EXTENT_CLEAR_DIRTY)
1371 clear_page_dirty_for_io(pages[i]);
1372 if (op & EXTENT_SET_WRITEBACK)
1373 set_page_writeback(pages[i]);
1374 if (op & EXTENT_END_WRITEBACK)
1375 end_page_writeback(pages[i]);
1376 if (op & EXTENT_CLEAR_UNLOCK_PAGE)
1377 unlock_page(pages[i]);
1378 page_cache_release(pages[i]);
1379 }
1380 nr_pages -= ret;
1381 index += ret;
1382 cond_resched();
1383 }
1384 return 0;
1385}
1386
1387/*
1388 * count the number of bytes in the tree that have a given bit(s)
1389 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1390 * cached. The total number found is returned.
1391 */
1392u64 count_range_bits(struct extent_io_tree *tree,
1393 u64 *start, u64 search_end, u64 max_bytes,
1394 unsigned long bits, int contig)
1395{
1396 struct rb_node *node;
1397 struct extent_state *state;
1398 u64 cur_start = *start;
1399 u64 total_bytes = 0;
1400 u64 last = 0;
1401 int found = 0;
1402
1403 if (search_end <= cur_start) {
1404 WARN_ON(1);
1405 return 0;
1406 }
1407
1408 spin_lock(&tree->lock);
1409 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1410 total_bytes = tree->dirty_bytes;
1411 goto out;
1412 }
1413 /*
1414 * this search will find all the extents that end after
1415 * our range starts.
1416 */
1417 node = tree_search(tree, cur_start);
1418 if (!node)
1419 goto out;
1420
1421 while (1) {
1422 state = rb_entry(node, struct extent_state, rb_node);
1423 if (state->start > search_end)
1424 break;
1425 if (contig && found && state->start > last + 1)
1426 break;
1427 if (state->end >= cur_start && (state->state & bits) == bits) {
1428 total_bytes += min(search_end, state->end) + 1 -
1429 max(cur_start, state->start);
1430 if (total_bytes >= max_bytes)
1431 break;
1432 if (!found) {
1433 *start = max(cur_start, state->start);
1434 found = 1;
1435 }
1436 last = state->end;
1437 } else if (contig && found) {
1438 break;
1439 }
1440 node = rb_next(node);
1441 if (!node)
1442 break;
1443 }
1444out:
1445 spin_unlock(&tree->lock);
1446 return total_bytes;
1447}
1448
1449/*
1450 * set the private field for a given byte offset in the tree. If there isn't
1451 * an extent_state there already, this does nothing.
1452 */
1453int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1454{
1455 struct rb_node *node;
1456 struct extent_state *state;
1457 int ret = 0;
1458
1459 spin_lock(&tree->lock);
1460 /*
1461 * this search will find all the extents that end after
1462 * our range starts.
1463 */
1464 node = tree_search(tree, start);
1465 if (!node) {
1466 ret = -ENOENT;
1467 goto out;
1468 }
1469 state = rb_entry(node, struct extent_state, rb_node);
1470 if (state->start != start) {
1471 ret = -ENOENT;
1472 goto out;
1473 }
1474 state->private = private;
1475out:
1476 spin_unlock(&tree->lock);
1477 return ret;
1478}
1479
1480int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1481{
1482 struct rb_node *node;
1483 struct extent_state *state;
1484 int ret = 0;
1485
1486 spin_lock(&tree->lock);
1487 /*
1488 * this search will find all the extents that end after
1489 * our range starts.
1490 */
1491 node = tree_search(tree, start);
1492 if (!node) {
1493 ret = -ENOENT;
1494 goto out;
1495 }
1496 state = rb_entry(node, struct extent_state, rb_node);
1497 if (state->start != start) {
1498 ret = -ENOENT;
1499 goto out;
1500 }
1501 *private = state->private;
1502out:
1503 spin_unlock(&tree->lock);
1504 return ret;
1505}
1506
1507/*
1508 * searches a range in the state tree for a given mask.
1509 * If 'filled' == 1, this returns 1 only if every extent in the tree
1510 * has the bits set. Otherwise, 1 is returned if any bit in the
1511 * range is found set.
1512 */
1513int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1514 int bits, int filled, struct extent_state *cached)
1515{
1516 struct extent_state *state = NULL;
1517 struct rb_node *node;
1518 int bitset = 0;
1519
1520 spin_lock(&tree->lock);
1521 if (cached && cached->tree && cached->start <= start &&
1522 cached->end > start)
1523 node = &cached->rb_node;
1524 else
1525 node = tree_search(tree, start);
1526 while (node && start <= end) {
1527 state = rb_entry(node, struct extent_state, rb_node);
1528
1529 if (filled && state->start > start) {
1530 bitset = 0;
1531 break;
1532 }
1533
1534 if (state->start > end)
1535 break;
1536
1537 if (state->state & bits) {
1538 bitset = 1;
1539 if (!filled)
1540 break;
1541 } else if (filled) {
1542 bitset = 0;
1543 break;
1544 }
1545
1546 if (state->end == (u64)-1)
1547 break;
1548
1549 start = state->end + 1;
1550 if (start > end)
1551 break;
1552 node = rb_next(node);
1553 if (!node) {
1554 if (filled)
1555 bitset = 0;
1556 break;
1557 }
1558 }
1559 spin_unlock(&tree->lock);
1560 return bitset;
1561}
1562
1563/*
1564 * helper function to set a given page up to date if all the
1565 * extents in the tree for that page are up to date
1566 */
1567static int check_page_uptodate(struct extent_io_tree *tree,
1568 struct page *page)
1569{
1570 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1571 u64 end = start + PAGE_CACHE_SIZE - 1;
1572 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1573 SetPageUptodate(page);
1574 return 0;
1575}
1576
1577/*
1578 * helper function to unlock a page if all the extents in the tree
1579 * for that page are unlocked
1580 */
1581static int check_page_locked(struct extent_io_tree *tree,
1582 struct page *page)
1583{
1584 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1585 u64 end = start + PAGE_CACHE_SIZE - 1;
1586 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
1587 unlock_page(page);
1588 return 0;
1589}
1590
1591/*
1592 * helper function to end page writeback if all the extents
1593 * in the tree for that page are done with writeback
1594 */
1595static int check_page_writeback(struct extent_io_tree *tree,
1596 struct page *page)
1597{
1598 end_page_writeback(page);
1599 return 0;
1600}
1601
1602/* lots and lots of room for performance fixes in the end_bio funcs */
1603
1604/*
1605 * after a writepage IO is done, we need to:
1606 * clear the uptodate bits on error
1607 * clear the writeback bits in the extent tree for this IO
1608 * end_page_writeback if the page has no more pending IO
1609 *
1610 * Scheduling is not allowed, so the extent state tree is expected
1611 * to have one and only one object corresponding to this IO.
1612 */
1613static void end_bio_extent_writepage(struct bio *bio, int err)
1614{
1615 int uptodate = err == 0;
1616 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1617 struct extent_io_tree *tree;
1618 u64 start;
1619 u64 end;
1620 int whole_page;
1621 int ret;
1622
1623 do {
1624 struct page *page = bvec->bv_page;
1625 tree = &BTRFS_I(page->mapping->host)->io_tree;
1626
1627 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1628 bvec->bv_offset;
1629 end = start + bvec->bv_len - 1;
1630
1631 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1632 whole_page = 1;
1633 else
1634 whole_page = 0;
1635
1636 if (--bvec >= bio->bi_io_vec)
1637 prefetchw(&bvec->bv_page->flags);
1638 if (tree->ops && tree->ops->writepage_end_io_hook) {
1639 ret = tree->ops->writepage_end_io_hook(page, start,
1640 end, NULL, uptodate);
1641 if (ret)
1642 uptodate = 0;
1643 }
1644
1645 if (!uptodate && tree->ops &&
1646 tree->ops->writepage_io_failed_hook) {
1647 ret = tree->ops->writepage_io_failed_hook(bio, page,
1648 start, end, NULL);
1649 if (ret == 0) {
1650 uptodate = (err == 0);
1651 continue;
1652 }
1653 }
1654
1655 if (!uptodate) {
1656 clear_extent_uptodate(tree, start, end, NULL, GFP_NOFS);
1657 ClearPageUptodate(page);
1658 SetPageError(page);
1659 }
1660
1661 if (whole_page)
1662 end_page_writeback(page);
1663 else
1664 check_page_writeback(tree, page);
1665 } while (bvec >= bio->bi_io_vec);
1666
1667 bio_put(bio);
1668}
1669
1670/*
1671 * after a readpage IO is done, we need to:
1672 * clear the uptodate bits on error
1673 * set the uptodate bits if things worked
1674 * set the page up to date if all extents in the tree are uptodate
1675 * clear the lock bit in the extent tree
1676 * unlock the page if there are no other extents locked for it
1677 *
1678 * Scheduling is not allowed, so the extent state tree is expected
1679 * to have one and only one object corresponding to this IO.
1680 */
1681static void end_bio_extent_readpage(struct bio *bio, int err)
1682{
1683 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1684 struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
1685 struct bio_vec *bvec = bio->bi_io_vec;
1686 struct extent_io_tree *tree;
1687 u64 start;
1688 u64 end;
1689 int whole_page;
1690 int ret;
1691
1692 if (err)
1693 uptodate = 0;
1694
1695 do {
1696 struct page *page = bvec->bv_page;
1697 struct extent_state *cached = NULL;
1698 struct extent_state *state;
1699
1700 tree = &BTRFS_I(page->mapping->host)->io_tree;
1701
1702 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1703 bvec->bv_offset;
1704 end = start + bvec->bv_len - 1;
1705
1706 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1707 whole_page = 1;
1708 else
1709 whole_page = 0;
1710
1711 if (++bvec <= bvec_end)
1712 prefetchw(&bvec->bv_page->flags);
1713
1714 spin_lock(&tree->lock);
1715 state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
1716 if (state && state->start == start) {
1717 /*
1718 * take a reference on the state, unlock will drop
1719 * the ref
1720 */
1721 cache_state(state, &cached);
1722 }
1723 spin_unlock(&tree->lock);
1724
1725 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1726 ret = tree->ops->readpage_end_io_hook(page, start, end,
1727 state);
1728 if (ret)
1729 uptodate = 0;
1730 }
1731 if (!uptodate && tree->ops &&
1732 tree->ops->readpage_io_failed_hook) {
1733 ret = tree->ops->readpage_io_failed_hook(bio, page,
1734 start, end, NULL);
1735 if (ret == 0) {
1736 uptodate =
1737 test_bit(BIO_UPTODATE, &bio->bi_flags);
1738 if (err)
1739 uptodate = 0;
1740 uncache_state(&cached);
1741 continue;
1742 }
1743 }
1744
1745 if (uptodate) {
1746 set_extent_uptodate(tree, start, end, &cached,
1747 GFP_ATOMIC);
1748 }
1749 unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
1750
1751 if (whole_page) {
1752 if (uptodate) {
1753 SetPageUptodate(page);
1754 } else {
1755 ClearPageUptodate(page);
1756 SetPageError(page);
1757 }
1758 unlock_page(page);
1759 } else {
1760 if (uptodate) {
1761 check_page_uptodate(tree, page);
1762 } else {
1763 ClearPageUptodate(page);
1764 SetPageError(page);
1765 }
1766 check_page_locked(tree, page);
1767 }
1768 } while (bvec <= bvec_end);
1769
1770 bio_put(bio);
1771}
1772
1773struct bio *
1774btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
1775 gfp_t gfp_flags)
1776{
1777 struct bio *bio;
1778
1779 bio = bio_alloc(gfp_flags, nr_vecs);
1780
1781 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
1782 while (!bio && (nr_vecs /= 2))
1783 bio = bio_alloc(gfp_flags, nr_vecs);
1784 }
1785
1786 if (bio) {
1787 bio->bi_size = 0;
1788 bio->bi_bdev = bdev;
1789 bio->bi_sector = first_sector;
1790 }
1791 return bio;
1792}
1793
1794static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
1795 unsigned long bio_flags)
1796{
1797 int ret = 0;
1798 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1799 struct page *page = bvec->bv_page;
1800 struct extent_io_tree *tree = bio->bi_private;
1801 u64 start;
1802
1803 start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1804
1805 bio->bi_private = NULL;
1806
1807 bio_get(bio);
1808
1809 if (tree->ops && tree->ops->submit_bio_hook)
1810 ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1811 mirror_num, bio_flags, start);
1812 else
1813 submit_bio(rw, bio);
1814 if (bio_flagged(bio, BIO_EOPNOTSUPP))
1815 ret = -EOPNOTSUPP;
1816 bio_put(bio);
1817 return ret;
1818}
1819
1820static int submit_extent_page(int rw, struct extent_io_tree *tree,
1821 struct page *page, sector_t sector,
1822 size_t size, unsigned long offset,
1823 struct block_device *bdev,
1824 struct bio **bio_ret,
1825 unsigned long max_pages,
1826 bio_end_io_t end_io_func,
1827 int mirror_num,
1828 unsigned long prev_bio_flags,
1829 unsigned long bio_flags)
1830{
1831 int ret = 0;
1832 struct bio *bio;
1833 int nr;
1834 int contig = 0;
1835 int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
1836 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
1837 size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
1838
1839 if (bio_ret && *bio_ret) {
1840 bio = *bio_ret;
1841 if (old_compressed)
1842 contig = bio->bi_sector == sector;
1843 else
1844 contig = bio->bi_sector + (bio->bi_size >> 9) ==
1845 sector;
1846
1847 if (prev_bio_flags != bio_flags || !contig ||
1848 (tree->ops && tree->ops->merge_bio_hook &&
1849 tree->ops->merge_bio_hook(page, offset, page_size, bio,
1850 bio_flags)) ||
1851 bio_add_page(bio, page, page_size, offset) < page_size) {
1852 ret = submit_one_bio(rw, bio, mirror_num,
1853 prev_bio_flags);
1854 bio = NULL;
1855 } else {
1856 return 0;
1857 }
1858 }
1859 if (this_compressed)
1860 nr = BIO_MAX_PAGES;
1861 else
1862 nr = bio_get_nr_vecs(bdev);
1863
1864 bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1865 if (!bio)
1866 return -ENOMEM;
1867
1868 bio_add_page(bio, page, page_size, offset);
1869 bio->bi_end_io = end_io_func;
1870 bio->bi_private = tree;
1871
1872 if (bio_ret)
1873 *bio_ret = bio;
1874 else
1875 ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
1876
1877 return ret;
1878}
1879
1880void set_page_extent_mapped(struct page *page)
1881{
1882 if (!PagePrivate(page)) {
1883 SetPagePrivate(page);
1884 page_cache_get(page);
1885 set_page_private(page, EXTENT_PAGE_PRIVATE);
1886 }
1887}
1888
1889static void set_page_extent_head(struct page *page, unsigned long len)
1890{
1891 WARN_ON(!PagePrivate(page));
1892 set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
1893}
1894
1895/*
1896 * basic readpage implementation. Locked extent state structs are inserted
1897 * into the tree that are removed when the IO is done (by the end_io
1898 * handlers)
1899 */
1900static int __extent_read_full_page(struct extent_io_tree *tree,
1901 struct page *page,
1902 get_extent_t *get_extent,
1903 struct bio **bio, int mirror_num,
1904 unsigned long *bio_flags)
1905{
1906 struct inode *inode = page->mapping->host;
1907 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1908 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1909 u64 end;
1910 u64 cur = start;
1911 u64 extent_offset;
1912 u64 last_byte = i_size_read(inode);
1913 u64 block_start;
1914 u64 cur_end;
1915 sector_t sector;
1916 struct extent_map *em;
1917 struct block_device *bdev;
1918 struct btrfs_ordered_extent *ordered;
1919 int ret;
1920 int nr = 0;
1921 size_t pg_offset = 0;
1922 size_t iosize;
1923 size_t disk_io_size;
1924 size_t blocksize = inode->i_sb->s_blocksize;
1925 unsigned long this_bio_flag = 0;
1926
1927 set_page_extent_mapped(page);
1928
1929 if (!PageUptodate(page)) {
1930 if (cleancache_get_page(page) == 0) {
1931 BUG_ON(blocksize != PAGE_SIZE);
1932 goto out;
1933 }
1934 }
1935
1936 end = page_end;
1937 while (1) {
1938 lock_extent(tree, start, end, GFP_NOFS);
1939 ordered = btrfs_lookup_ordered_extent(inode, start);
1940 if (!ordered)
1941 break;
1942 unlock_extent(tree, start, end, GFP_NOFS);
1943 btrfs_start_ordered_extent(inode, ordered, 1);
1944 btrfs_put_ordered_extent(ordered);
1945 }
1946
1947 if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
1948 char *userpage;
1949 size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
1950
1951 if (zero_offset) {
1952 iosize = PAGE_CACHE_SIZE - zero_offset;
1953 userpage = kmap_atomic(page, KM_USER0);
1954 memset(userpage + zero_offset, 0, iosize);
1955 flush_dcache_page(page);
1956 kunmap_atomic(userpage, KM_USER0);
1957 }
1958 }
1959 while (cur <= end) {
1960 if (cur >= last_byte) {
1961 char *userpage;
1962 struct extent_state *cached = NULL;
1963
1964 iosize = PAGE_CACHE_SIZE - pg_offset;
1965 userpage = kmap_atomic(page, KM_USER0);
1966 memset(userpage + pg_offset, 0, iosize);
1967 flush_dcache_page(page);
1968 kunmap_atomic(userpage, KM_USER0);
1969 set_extent_uptodate(tree, cur, cur + iosize - 1,
1970 &cached, GFP_NOFS);
1971 unlock_extent_cached(tree, cur, cur + iosize - 1,
1972 &cached, GFP_NOFS);
1973 break;
1974 }
1975 em = get_extent(inode, page, pg_offset, cur,
1976 end - cur + 1, 0);
1977 if (IS_ERR_OR_NULL(em)) {
1978 SetPageError(page);
1979 unlock_extent(tree, cur, end, GFP_NOFS);
1980 break;
1981 }
1982 extent_offset = cur - em->start;
1983 BUG_ON(extent_map_end(em) <= cur);
1984 BUG_ON(end < cur);
1985
1986 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1987 this_bio_flag = EXTENT_BIO_COMPRESSED;
1988 extent_set_compress_type(&this_bio_flag,
1989 em->compress_type);
1990 }
1991
1992 iosize = min(extent_map_end(em) - cur, end - cur + 1);
1993 cur_end = min(extent_map_end(em) - 1, end);
1994 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
1995 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
1996 disk_io_size = em->block_len;
1997 sector = em->block_start >> 9;
1998 } else {
1999 sector = (em->block_start + extent_offset) >> 9;
2000 disk_io_size = iosize;
2001 }
2002 bdev = em->bdev;
2003 block_start = em->block_start;
2004 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2005 block_start = EXTENT_MAP_HOLE;
2006 free_extent_map(em);
2007 em = NULL;
2008
2009 /* we've found a hole, just zero and go on */
2010 if (block_start == EXTENT_MAP_HOLE) {
2011 char *userpage;
2012 struct extent_state *cached = NULL;
2013
2014 userpage = kmap_atomic(page, KM_USER0);
2015 memset(userpage + pg_offset, 0, iosize);
2016 flush_dcache_page(page);
2017 kunmap_atomic(userpage, KM_USER0);
2018
2019 set_extent_uptodate(tree, cur, cur + iosize - 1,
2020 &cached, GFP_NOFS);
2021 unlock_extent_cached(tree, cur, cur + iosize - 1,
2022 &cached, GFP_NOFS);
2023 cur = cur + iosize;
2024 pg_offset += iosize;
2025 continue;
2026 }
2027 /* the get_extent function already copied into the page */
2028 if (test_range_bit(tree, cur, cur_end,
2029 EXTENT_UPTODATE, 1, NULL)) {
2030 check_page_uptodate(tree, page);
2031 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2032 cur = cur + iosize;
2033 pg_offset += iosize;
2034 continue;
2035 }
2036 /* we have an inline extent but it didn't get marked up
2037 * to date. Error out
2038 */
2039 if (block_start == EXTENT_MAP_INLINE) {
2040 SetPageError(page);
2041 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2042 cur = cur + iosize;
2043 pg_offset += iosize;
2044 continue;
2045 }
2046
2047 ret = 0;
2048 if (tree->ops && tree->ops->readpage_io_hook) {
2049 ret = tree->ops->readpage_io_hook(page, cur,
2050 cur + iosize - 1);
2051 }
2052 if (!ret) {
2053 unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
2054 pnr -= page->index;
2055 ret = submit_extent_page(READ, tree, page,
2056 sector, disk_io_size, pg_offset,
2057 bdev, bio, pnr,
2058 end_bio_extent_readpage, mirror_num,
2059 *bio_flags,
2060 this_bio_flag);
2061 nr++;
2062 *bio_flags = this_bio_flag;
2063 }
2064 if (ret)
2065 SetPageError(page);
2066 cur = cur + iosize;
2067 pg_offset += iosize;
2068 }
2069out:
2070 if (!nr) {
2071 if (!PageError(page))
2072 SetPageUptodate(page);
2073 unlock_page(page);
2074 }
2075 return 0;
2076}
2077
2078int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
2079 get_extent_t *get_extent)
2080{
2081 struct bio *bio = NULL;
2082 unsigned long bio_flags = 0;
2083 int ret;
2084
2085 ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
2086 &bio_flags);
2087 if (bio)
2088 ret = submit_one_bio(READ, bio, 0, bio_flags);
2089 return ret;
2090}
2091
2092static noinline void update_nr_written(struct page *page,
2093 struct writeback_control *wbc,
2094 unsigned long nr_written)
2095{
2096 wbc->nr_to_write -= nr_written;
2097 if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
2098 wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
2099 page->mapping->writeback_index = page->index + nr_written;
2100}
2101
2102/*
2103 * the writepage semantics are similar to regular writepage. extent
2104 * records are inserted to lock ranges in the tree, and as dirty areas
2105 * are found, they are marked writeback. Then the lock bits are removed
2106 * and the end_io handler clears the writeback ranges
2107 */
2108static int __extent_writepage(struct page *page, struct writeback_control *wbc,
2109 void *data)
2110{
2111 struct inode *inode = page->mapping->host;
2112 struct extent_page_data *epd = data;
2113 struct extent_io_tree *tree = epd->tree;
2114 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2115 u64 delalloc_start;
2116 u64 page_end = start + PAGE_CACHE_SIZE - 1;
2117 u64 end;
2118 u64 cur = start;
2119 u64 extent_offset;
2120 u64 last_byte = i_size_read(inode);
2121 u64 block_start;
2122 u64 iosize;
2123 sector_t sector;
2124 struct extent_state *cached_state = NULL;
2125 struct extent_map *em;
2126 struct block_device *bdev;
2127 int ret;
2128 int nr = 0;
2129 size_t pg_offset = 0;
2130 size_t blocksize;
2131 loff_t i_size = i_size_read(inode);
2132 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2133 u64 nr_delalloc;
2134 u64 delalloc_end;
2135 int page_started;
2136 int compressed;
2137 int write_flags;
2138 unsigned long nr_written = 0;
2139
2140 if (wbc->sync_mode == WB_SYNC_ALL)
2141 write_flags = WRITE_SYNC;
2142 else
2143 write_flags = WRITE;
2144
2145 trace___extent_writepage(page, inode, wbc);
2146
2147 WARN_ON(!PageLocked(page));
2148 pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2149 if (page->index > end_index ||
2150 (page->index == end_index && !pg_offset)) {
2151 page->mapping->a_ops->invalidatepage(page, 0);
2152 unlock_page(page);
2153 return 0;
2154 }
2155
2156 if (page->index == end_index) {
2157 char *userpage;
2158
2159 userpage = kmap_atomic(page, KM_USER0);
2160 memset(userpage + pg_offset, 0,
2161 PAGE_CACHE_SIZE - pg_offset);
2162 kunmap_atomic(userpage, KM_USER0);
2163 flush_dcache_page(page);
2164 }
2165 pg_offset = 0;
2166
2167 set_page_extent_mapped(page);
2168
2169 delalloc_start = start;
2170 delalloc_end = 0;
2171 page_started = 0;
2172 if (!epd->extent_locked) {
2173 u64 delalloc_to_write = 0;
2174 /*
2175 * make sure the wbc mapping index is at least updated
2176 * to this page.
2177 */
2178 update_nr_written(page, wbc, 0);
2179
2180 while (delalloc_end < page_end) {
2181 nr_delalloc = find_lock_delalloc_range(inode, tree,
2182 page,
2183 &delalloc_start,
2184 &delalloc_end,
2185 128 * 1024 * 1024);
2186 if (nr_delalloc == 0) {
2187 delalloc_start = delalloc_end + 1;
2188 continue;
2189 }
2190 tree->ops->fill_delalloc(inode, page, delalloc_start,
2191 delalloc_end, &page_started,
2192 &nr_written);
2193 /*
2194 * delalloc_end is already one less than the total
2195 * length, so we don't subtract one from
2196 * PAGE_CACHE_SIZE
2197 */
2198 delalloc_to_write += (delalloc_end - delalloc_start +
2199 PAGE_CACHE_SIZE) >>
2200 PAGE_CACHE_SHIFT;
2201 delalloc_start = delalloc_end + 1;
2202 }
2203 if (wbc->nr_to_write < delalloc_to_write) {
2204 int thresh = 8192;
2205
2206 if (delalloc_to_write < thresh * 2)
2207 thresh = delalloc_to_write;
2208 wbc->nr_to_write = min_t(u64, delalloc_to_write,
2209 thresh);
2210 }
2211
2212 /* did the fill delalloc function already unlock and start
2213 * the IO?
2214 */
2215 if (page_started) {
2216 ret = 0;
2217 /*
2218 * we've unlocked the page, so we can't update
2219 * the mapping's writeback index, just update
2220 * nr_to_write.
2221 */
2222 wbc->nr_to_write -= nr_written;
2223 goto done_unlocked;
2224 }
2225 }
2226 if (tree->ops && tree->ops->writepage_start_hook) {
2227 ret = tree->ops->writepage_start_hook(page, start,
2228 page_end);
2229 if (ret == -EAGAIN) {
2230 redirty_page_for_writepage(wbc, page);
2231 update_nr_written(page, wbc, nr_written);
2232 unlock_page(page);
2233 ret = 0;
2234 goto done_unlocked;
2235 }
2236 }
2237
2238 /*
2239 * we don't want to touch the inode after unlocking the page,
2240 * so we update the mapping writeback index now
2241 */
2242 update_nr_written(page, wbc, nr_written + 1);
2243
2244 end = page_end;
2245 if (last_byte <= start) {
2246 if (tree->ops && tree->ops->writepage_end_io_hook)
2247 tree->ops->writepage_end_io_hook(page, start,
2248 page_end, NULL, 1);
2249 goto done;
2250 }
2251
2252 blocksize = inode->i_sb->s_blocksize;
2253
2254 while (cur <= end) {
2255 if (cur >= last_byte) {
2256 if (tree->ops && tree->ops->writepage_end_io_hook)
2257 tree->ops->writepage_end_io_hook(page, cur,
2258 page_end, NULL, 1);
2259 break;
2260 }
2261 em = epd->get_extent(inode, page, pg_offset, cur,
2262 end - cur + 1, 1);
2263 if (IS_ERR_OR_NULL(em)) {
2264 SetPageError(page);
2265 break;
2266 }
2267
2268 extent_offset = cur - em->start;
2269 BUG_ON(extent_map_end(em) <= cur);
2270 BUG_ON(end < cur);
2271 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2272 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2273 sector = (em->block_start + extent_offset) >> 9;
2274 bdev = em->bdev;
2275 block_start = em->block_start;
2276 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2277 free_extent_map(em);
2278 em = NULL;
2279
2280 /*
2281 * compressed and inline extents are written through other
2282 * paths in the FS
2283 */
2284 if (compressed || block_start == EXTENT_MAP_HOLE ||
2285 block_start == EXTENT_MAP_INLINE) {
2286 /*
2287 * end_io notification does not happen here for
2288 * compressed extents
2289 */
2290 if (!compressed && tree->ops &&
2291 tree->ops->writepage_end_io_hook)
2292 tree->ops->writepage_end_io_hook(page, cur,
2293 cur + iosize - 1,
2294 NULL, 1);
2295 else if (compressed) {
2296 /* we don't want to end_page_writeback on
2297 * a compressed extent. this happens
2298 * elsewhere
2299 */
2300 nr++;
2301 }
2302
2303 cur += iosize;
2304 pg_offset += iosize;
2305 continue;
2306 }
2307 /* leave this out until we have a page_mkwrite call */
2308 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2309 EXTENT_DIRTY, 0, NULL)) {
2310 cur = cur + iosize;
2311 pg_offset += iosize;
2312 continue;
2313 }
2314
2315 if (tree->ops && tree->ops->writepage_io_hook) {
2316 ret = tree->ops->writepage_io_hook(page, cur,
2317 cur + iosize - 1);
2318 } else {
2319 ret = 0;
2320 }
2321 if (ret) {
2322 SetPageError(page);
2323 } else {
2324 unsigned long max_nr = end_index + 1;
2325
2326 set_range_writeback(tree, cur, cur + iosize - 1);
2327 if (!PageWriteback(page)) {
2328 printk(KERN_ERR "btrfs warning page %lu not "
2329 "writeback, cur %llu end %llu\n",
2330 page->index, (unsigned long long)cur,
2331 (unsigned long long)end);
2332 }
2333
2334 ret = submit_extent_page(write_flags, tree, page,
2335 sector, iosize, pg_offset,
2336 bdev, &epd->bio, max_nr,
2337 end_bio_extent_writepage,
2338 0, 0, 0);
2339 if (ret)
2340 SetPageError(page);
2341 }
2342 cur = cur + iosize;
2343 pg_offset += iosize;
2344 nr++;
2345 }
2346done:
2347 if (nr == 0) {
2348 /* make sure the mapping tag for page dirty gets cleared */
2349 set_page_writeback(page);
2350 end_page_writeback(page);
2351 }
2352 unlock_page(page);
2353
2354done_unlocked:
2355
2356 /* drop our reference on any cached states */
2357 free_extent_state(cached_state);
2358 return 0;
2359}
2360
2361/**
2362 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
2363 * @mapping: address space structure to write
2364 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
2365 * @writepage: function called for each page
2366 * @data: data passed to writepage function
2367 *
2368 * If a page is already under I/O, write_cache_pages() skips it, even
2369 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
2370 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
2371 * and msync() need to guarantee that all the data which was dirty at the time
2372 * the call was made get new I/O started against them. If wbc->sync_mode is
2373 * WB_SYNC_ALL then we were called for data integrity and we must wait for
2374 * existing IO to complete.
2375 */
2376static int extent_write_cache_pages(struct extent_io_tree *tree,
2377 struct address_space *mapping,
2378 struct writeback_control *wbc,
2379 writepage_t writepage, void *data,
2380 void (*flush_fn)(void *))
2381{
2382 int ret = 0;
2383 int done = 0;
2384 int nr_to_write_done = 0;
2385 struct pagevec pvec;
2386 int nr_pages;
2387 pgoff_t index;
2388 pgoff_t end; /* Inclusive */
2389 int scanned = 0;
2390 int tag;
2391
2392 pagevec_init(&pvec, 0);
2393 if (wbc->range_cyclic) {
2394 index = mapping->writeback_index; /* Start from prev offset */
2395 end = -1;
2396 } else {
2397 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2398 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2399 scanned = 1;
2400 }
2401 if (wbc->sync_mode == WB_SYNC_ALL)
2402 tag = PAGECACHE_TAG_TOWRITE;
2403 else
2404 tag = PAGECACHE_TAG_DIRTY;
2405retry:
2406 if (wbc->sync_mode == WB_SYNC_ALL)
2407 tag_pages_for_writeback(mapping, index, end);
2408 while (!done && !nr_to_write_done && (index <= end) &&
2409 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2410 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2411 unsigned i;
2412
2413 scanned = 1;
2414 for (i = 0; i < nr_pages; i++) {
2415 struct page *page = pvec.pages[i];
2416
2417 /*
2418 * At this point we hold neither mapping->tree_lock nor
2419 * lock on the page itself: the page may be truncated or
2420 * invalidated (changing page->mapping to NULL), or even
2421 * swizzled back from swapper_space to tmpfs file
2422 * mapping
2423 */
2424 if (tree->ops && tree->ops->write_cache_pages_lock_hook)
2425 tree->ops->write_cache_pages_lock_hook(page);
2426 else
2427 lock_page(page);
2428
2429 if (unlikely(page->mapping != mapping)) {
2430 unlock_page(page);
2431 continue;
2432 }
2433
2434 if (!wbc->range_cyclic && page->index > end) {
2435 done = 1;
2436 unlock_page(page);
2437 continue;
2438 }
2439
2440 if (wbc->sync_mode != WB_SYNC_NONE) {
2441 if (PageWriteback(page))
2442 flush_fn(data);
2443 wait_on_page_writeback(page);
2444 }
2445
2446 if (PageWriteback(page) ||
2447 !clear_page_dirty_for_io(page)) {
2448 unlock_page(page);
2449 continue;
2450 }
2451
2452 ret = (*writepage)(page, wbc, data);
2453
2454 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
2455 unlock_page(page);
2456 ret = 0;
2457 }
2458 if (ret)
2459 done = 1;
2460
2461 /*
2462 * the filesystem may choose to bump up nr_to_write.
2463 * We have to make sure to honor the new nr_to_write
2464 * at any time
2465 */
2466 nr_to_write_done = wbc->nr_to_write <= 0;
2467 }
2468 pagevec_release(&pvec);
2469 cond_resched();
2470 }
2471 if (!scanned && !done) {
2472 /*
2473 * We hit the last page and there is more work to be done: wrap
2474 * back to the start of the file
2475 */
2476 scanned = 1;
2477 index = 0;
2478 goto retry;
2479 }
2480 return ret;
2481}
2482
2483static void flush_epd_write_bio(struct extent_page_data *epd)
2484{
2485 if (epd->bio) {
2486 if (epd->sync_io)
2487 submit_one_bio(WRITE_SYNC, epd->bio, 0, 0);
2488 else
2489 submit_one_bio(WRITE, epd->bio, 0, 0);
2490 epd->bio = NULL;
2491 }
2492}
2493
2494static noinline void flush_write_bio(void *data)
2495{
2496 struct extent_page_data *epd = data;
2497 flush_epd_write_bio(epd);
2498}
2499
2500int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
2501 get_extent_t *get_extent,
2502 struct writeback_control *wbc)
2503{
2504 int ret;
2505 struct extent_page_data epd = {
2506 .bio = NULL,
2507 .tree = tree,
2508 .get_extent = get_extent,
2509 .extent_locked = 0,
2510 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2511 };
2512
2513 ret = __extent_writepage(page, wbc, &epd);
2514
2515 flush_epd_write_bio(&epd);
2516 return ret;
2517}
2518
2519int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
2520 u64 start, u64 end, get_extent_t *get_extent,
2521 int mode)
2522{
2523 int ret = 0;
2524 struct address_space *mapping = inode->i_mapping;
2525 struct page *page;
2526 unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
2527 PAGE_CACHE_SHIFT;
2528
2529 struct extent_page_data epd = {
2530 .bio = NULL,
2531 .tree = tree,
2532 .get_extent = get_extent,
2533 .extent_locked = 1,
2534 .sync_io = mode == WB_SYNC_ALL,
2535 };
2536 struct writeback_control wbc_writepages = {
2537 .sync_mode = mode,
2538 .nr_to_write = nr_pages * 2,
2539 .range_start = start,
2540 .range_end = end + 1,
2541 };
2542
2543 while (start <= end) {
2544 page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
2545 if (clear_page_dirty_for_io(page))
2546 ret = __extent_writepage(page, &wbc_writepages, &epd);
2547 else {
2548 if (tree->ops && tree->ops->writepage_end_io_hook)
2549 tree->ops->writepage_end_io_hook(page, start,
2550 start + PAGE_CACHE_SIZE - 1,
2551 NULL, 1);
2552 unlock_page(page);
2553 }
2554 page_cache_release(page);
2555 start += PAGE_CACHE_SIZE;
2556 }
2557
2558 flush_epd_write_bio(&epd);
2559 return ret;
2560}
2561
2562int extent_writepages(struct extent_io_tree *tree,
2563 struct address_space *mapping,
2564 get_extent_t *get_extent,
2565 struct writeback_control *wbc)
2566{
2567 int ret = 0;
2568 struct extent_page_data epd = {
2569 .bio = NULL,
2570 .tree = tree,
2571 .get_extent = get_extent,
2572 .extent_locked = 0,
2573 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2574 };
2575
2576 ret = extent_write_cache_pages(tree, mapping, wbc,
2577 __extent_writepage, &epd,
2578 flush_write_bio);
2579 flush_epd_write_bio(&epd);
2580 return ret;
2581}
2582
2583int extent_readpages(struct extent_io_tree *tree,
2584 struct address_space *mapping,
2585 struct list_head *pages, unsigned nr_pages,
2586 get_extent_t get_extent)
2587{
2588 struct bio *bio = NULL;
2589 unsigned page_idx;
2590 unsigned long bio_flags = 0;
2591
2592 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
2593 struct page *page = list_entry(pages->prev, struct page, lru);
2594
2595 prefetchw(&page->flags);
2596 list_del(&page->lru);
2597 if (!add_to_page_cache_lru(page, mapping,
2598 page->index, GFP_NOFS)) {
2599 __extent_read_full_page(tree, page, get_extent,
2600 &bio, 0, &bio_flags);
2601 }
2602 page_cache_release(page);
2603 }
2604 BUG_ON(!list_empty(pages));
2605 if (bio)
2606 submit_one_bio(READ, bio, 0, bio_flags);
2607 return 0;
2608}
2609
2610/*
2611 * basic invalidatepage code, this waits on any locked or writeback
2612 * ranges corresponding to the page, and then deletes any extent state
2613 * records from the tree
2614 */
2615int extent_invalidatepage(struct extent_io_tree *tree,
2616 struct page *page, unsigned long offset)
2617{
2618 struct extent_state *cached_state = NULL;
2619 u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
2620 u64 end = start + PAGE_CACHE_SIZE - 1;
2621 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
2622
2623 start += (offset + blocksize - 1) & ~(blocksize - 1);
2624 if (start > end)
2625 return 0;
2626
2627 lock_extent_bits(tree, start, end, 0, &cached_state, GFP_NOFS);
2628 wait_on_page_writeback(page);
2629 clear_extent_bit(tree, start, end,
2630 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
2631 EXTENT_DO_ACCOUNTING,
2632 1, 1, &cached_state, GFP_NOFS);
2633 return 0;
2634}
2635
2636/*
2637 * a helper for releasepage, this tests for areas of the page that
2638 * are locked or under IO and drops the related state bits if it is safe
2639 * to drop the page.
2640 */
2641int try_release_extent_state(struct extent_map_tree *map,
2642 struct extent_io_tree *tree, struct page *page,
2643 gfp_t mask)
2644{
2645 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2646 u64 end = start + PAGE_CACHE_SIZE - 1;
2647 int ret = 1;
2648
2649 if (test_range_bit(tree, start, end,
2650 EXTENT_IOBITS, 0, NULL))
2651 ret = 0;
2652 else {
2653 if ((mask & GFP_NOFS) == GFP_NOFS)
2654 mask = GFP_NOFS;
2655 /*
2656 * at this point we can safely clear everything except the
2657 * locked bit and the nodatasum bit
2658 */
2659 ret = clear_extent_bit(tree, start, end,
2660 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
2661 0, 0, NULL, mask);
2662
2663 /* if clear_extent_bit failed for enomem reasons,
2664 * we can't allow the release to continue.
2665 */
2666 if (ret < 0)
2667 ret = 0;
2668 else
2669 ret = 1;
2670 }
2671 return ret;
2672}
2673
2674/*
2675 * a helper for releasepage. As long as there are no locked extents
2676 * in the range corresponding to the page, both state records and extent
2677 * map records are removed
2678 */
2679int try_release_extent_mapping(struct extent_map_tree *map,
2680 struct extent_io_tree *tree, struct page *page,
2681 gfp_t mask)
2682{
2683 struct extent_map *em;
2684 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2685 u64 end = start + PAGE_CACHE_SIZE - 1;
2686
2687 if ((mask & __GFP_WAIT) &&
2688 page->mapping->host->i_size > 16 * 1024 * 1024) {
2689 u64 len;
2690 while (start <= end) {
2691 len = end - start + 1;
2692 write_lock(&map->lock);
2693 em = lookup_extent_mapping(map, start, len);
2694 if (IS_ERR_OR_NULL(em)) {
2695 write_unlock(&map->lock);
2696 break;
2697 }
2698 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
2699 em->start != start) {
2700 write_unlock(&map->lock);
2701 free_extent_map(em);
2702 break;
2703 }
2704 if (!test_range_bit(tree, em->start,
2705 extent_map_end(em) - 1,
2706 EXTENT_LOCKED | EXTENT_WRITEBACK,
2707 0, NULL)) {
2708 remove_extent_mapping(map, em);
2709 /* once for the rb tree */
2710 free_extent_map(em);
2711 }
2712 start = extent_map_end(em);
2713 write_unlock(&map->lock);
2714
2715 /* once for us */
2716 free_extent_map(em);
2717 }
2718 }
2719 return try_release_extent_state(map, tree, page, mask);
2720}
2721
2722/*
2723 * helper function for fiemap, which doesn't want to see any holes.
2724 * This maps until we find something past 'last'
2725 */
2726static struct extent_map *get_extent_skip_holes(struct inode *inode,
2727 u64 offset,
2728 u64 last,
2729 get_extent_t *get_extent)
2730{
2731 u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
2732 struct extent_map *em;
2733 u64 len;
2734
2735 if (offset >= last)
2736 return NULL;
2737
2738 while(1) {
2739 len = last - offset;
2740 if (len == 0)
2741 break;
2742 len = (len + sectorsize - 1) & ~(sectorsize - 1);
2743 em = get_extent(inode, NULL, 0, offset, len, 0);
2744 if (IS_ERR_OR_NULL(em))
2745 return em;
2746
2747 /* if this isn't a hole return it */
2748 if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
2749 em->block_start != EXTENT_MAP_HOLE) {
2750 return em;
2751 }
2752
2753 /* this is a hole, advance to the next extent */
2754 offset = extent_map_end(em);
2755 free_extent_map(em);
2756 if (offset >= last)
2757 break;
2758 }
2759 return NULL;
2760}
2761
2762int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
2763 __u64 start, __u64 len, get_extent_t *get_extent)
2764{
2765 int ret = 0;
2766 u64 off = start;
2767 u64 max = start + len;
2768 u32 flags = 0;
2769 u32 found_type;
2770 u64 last;
2771 u64 last_for_get_extent = 0;
2772 u64 disko = 0;
2773 u64 isize = i_size_read(inode);
2774 struct btrfs_key found_key;
2775 struct extent_map *em = NULL;
2776 struct extent_state *cached_state = NULL;
2777 struct btrfs_path *path;
2778 struct btrfs_file_extent_item *item;
2779 int end = 0;
2780 u64 em_start = 0;
2781 u64 em_len = 0;
2782 u64 em_end = 0;
2783 unsigned long emflags;
2784
2785 if (len == 0)
2786 return -EINVAL;
2787
2788 path = btrfs_alloc_path();
2789 if (!path)
2790 return -ENOMEM;
2791 path->leave_spinning = 1;
2792
2793 /*
2794 * lookup the last file extent. We're not using i_size here
2795 * because there might be preallocation past i_size
2796 */
2797 ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
2798 path, btrfs_ino(inode), -1, 0);
2799 if (ret < 0) {
2800 btrfs_free_path(path);
2801 return ret;
2802 }
2803 WARN_ON(!ret);
2804 path->slots[0]--;
2805 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2806 struct btrfs_file_extent_item);
2807 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
2808 found_type = btrfs_key_type(&found_key);
2809
2810 /* No extents, but there might be delalloc bits */
2811 if (found_key.objectid != btrfs_ino(inode) ||
2812 found_type != BTRFS_EXTENT_DATA_KEY) {
2813 /* have to trust i_size as the end */
2814 last = (u64)-1;
2815 last_for_get_extent = isize;
2816 } else {
2817 /*
2818 * remember the start of the last extent. There are a
2819 * bunch of different factors that go into the length of the
2820 * extent, so its much less complex to remember where it started
2821 */
2822 last = found_key.offset;
2823 last_for_get_extent = last + 1;
2824 }
2825 btrfs_free_path(path);
2826
2827 /*
2828 * we might have some extents allocated but more delalloc past those
2829 * extents. so, we trust isize unless the start of the last extent is
2830 * beyond isize
2831 */
2832 if (last < isize) {
2833 last = (u64)-1;
2834 last_for_get_extent = isize;
2835 }
2836
2837 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
2838 &cached_state, GFP_NOFS);
2839
2840 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2841 get_extent);
2842 if (!em)
2843 goto out;
2844 if (IS_ERR(em)) {
2845 ret = PTR_ERR(em);
2846 goto out;
2847 }
2848
2849 while (!end) {
2850 u64 offset_in_extent;
2851
2852 /* break if the extent we found is outside the range */
2853 if (em->start >= max || extent_map_end(em) < off)
2854 break;
2855
2856 /*
2857 * get_extent may return an extent that starts before our
2858 * requested range. We have to make sure the ranges
2859 * we return to fiemap always move forward and don't
2860 * overlap, so adjust the offsets here
2861 */
2862 em_start = max(em->start, off);
2863
2864 /*
2865 * record the offset from the start of the extent
2866 * for adjusting the disk offset below
2867 */
2868 offset_in_extent = em_start - em->start;
2869 em_end = extent_map_end(em);
2870 em_len = em_end - em_start;
2871 emflags = em->flags;
2872 disko = 0;
2873 flags = 0;
2874
2875 /*
2876 * bump off for our next call to get_extent
2877 */
2878 off = extent_map_end(em);
2879 if (off >= max)
2880 end = 1;
2881
2882 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
2883 end = 1;
2884 flags |= FIEMAP_EXTENT_LAST;
2885 } else if (em->block_start == EXTENT_MAP_INLINE) {
2886 flags |= (FIEMAP_EXTENT_DATA_INLINE |
2887 FIEMAP_EXTENT_NOT_ALIGNED);
2888 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
2889 flags |= (FIEMAP_EXTENT_DELALLOC |
2890 FIEMAP_EXTENT_UNKNOWN);
2891 } else {
2892 disko = em->block_start + offset_in_extent;
2893 }
2894 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
2895 flags |= FIEMAP_EXTENT_ENCODED;
2896
2897 free_extent_map(em);
2898 em = NULL;
2899 if ((em_start >= last) || em_len == (u64)-1 ||
2900 (last == (u64)-1 && isize <= em_end)) {
2901 flags |= FIEMAP_EXTENT_LAST;
2902 end = 1;
2903 }
2904
2905 /* now scan forward to see if this is really the last extent. */
2906 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2907 get_extent);
2908 if (IS_ERR(em)) {
2909 ret = PTR_ERR(em);
2910 goto out;
2911 }
2912 if (!em) {
2913 flags |= FIEMAP_EXTENT_LAST;
2914 end = 1;
2915 }
2916 ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
2917 em_len, flags);
2918 if (ret)
2919 goto out_free;
2920 }
2921out_free:
2922 free_extent_map(em);
2923out:
2924 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len,
2925 &cached_state, GFP_NOFS);
2926 return ret;
2927}
2928
2929static inline struct page *extent_buffer_page(struct extent_buffer *eb,
2930 unsigned long i)
2931{
2932 struct page *p;
2933 struct address_space *mapping;
2934
2935 if (i == 0)
2936 return eb->first_page;
2937 i += eb->start >> PAGE_CACHE_SHIFT;
2938 mapping = eb->first_page->mapping;
2939 if (!mapping)
2940 return NULL;
2941
2942 /*
2943 * extent_buffer_page is only called after pinning the page
2944 * by increasing the reference count. So we know the page must
2945 * be in the radix tree.
2946 */
2947 rcu_read_lock();
2948 p = radix_tree_lookup(&mapping->page_tree, i);
2949 rcu_read_unlock();
2950
2951 return p;
2952}
2953
2954static inline unsigned long num_extent_pages(u64 start, u64 len)
2955{
2956 return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
2957 (start >> PAGE_CACHE_SHIFT);
2958}
2959
2960static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
2961 u64 start,
2962 unsigned long len,
2963 gfp_t mask)
2964{
2965 struct extent_buffer *eb = NULL;
2966#if LEAK_DEBUG
2967 unsigned long flags;
2968#endif
2969
2970 eb = kmem_cache_zalloc(extent_buffer_cache, mask);
2971 if (eb == NULL)
2972 return NULL;
2973 eb->start = start;
2974 eb->len = len;
2975 rwlock_init(&eb->lock);
2976 atomic_set(&eb->write_locks, 0);
2977 atomic_set(&eb->read_locks, 0);
2978 atomic_set(&eb->blocking_readers, 0);
2979 atomic_set(&eb->blocking_writers, 0);
2980 atomic_set(&eb->spinning_readers, 0);
2981 atomic_set(&eb->spinning_writers, 0);
2982 init_waitqueue_head(&eb->write_lock_wq);
2983 init_waitqueue_head(&eb->read_lock_wq);
2984
2985#if LEAK_DEBUG
2986 spin_lock_irqsave(&leak_lock, flags);
2987 list_add(&eb->leak_list, &buffers);
2988 spin_unlock_irqrestore(&leak_lock, flags);
2989#endif
2990 atomic_set(&eb->refs, 1);
2991
2992 return eb;
2993}
2994
2995static void __free_extent_buffer(struct extent_buffer *eb)
2996{
2997#if LEAK_DEBUG
2998 unsigned long flags;
2999 spin_lock_irqsave(&leak_lock, flags);
3000 list_del(&eb->leak_list);
3001 spin_unlock_irqrestore(&leak_lock, flags);
3002#endif
3003 kmem_cache_free(extent_buffer_cache, eb);
3004}
3005
3006/*
3007 * Helper for releasing extent buffer page.
3008 */
3009static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
3010 unsigned long start_idx)
3011{
3012 unsigned long index;
3013 struct page *page;
3014
3015 if (!eb->first_page)
3016 return;
3017
3018 index = num_extent_pages(eb->start, eb->len);
3019 if (start_idx >= index)
3020 return;
3021
3022 do {
3023 index--;
3024 page = extent_buffer_page(eb, index);
3025 if (page)
3026 page_cache_release(page);
3027 } while (index != start_idx);
3028}
3029
3030/*
3031 * Helper for releasing the extent buffer.
3032 */
3033static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
3034{
3035 btrfs_release_extent_buffer_page(eb, 0);
3036 __free_extent_buffer(eb);
3037}
3038
3039struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
3040 u64 start, unsigned long len,
3041 struct page *page0)
3042{
3043 unsigned long num_pages = num_extent_pages(start, len);
3044 unsigned long i;
3045 unsigned long index = start >> PAGE_CACHE_SHIFT;
3046 struct extent_buffer *eb;
3047 struct extent_buffer *exists = NULL;
3048 struct page *p;
3049 struct address_space *mapping = tree->mapping;
3050 int uptodate = 1;
3051 int ret;
3052
3053 rcu_read_lock();
3054 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3055 if (eb && atomic_inc_not_zero(&eb->refs)) {
3056 rcu_read_unlock();
3057 mark_page_accessed(eb->first_page);
3058 return eb;
3059 }
3060 rcu_read_unlock();
3061
3062 eb = __alloc_extent_buffer(tree, start, len, GFP_NOFS);
3063 if (!eb)
3064 return NULL;
3065
3066 if (page0) {
3067 eb->first_page = page0;
3068 i = 1;
3069 index++;
3070 page_cache_get(page0);
3071 mark_page_accessed(page0);
3072 set_page_extent_mapped(page0);
3073 set_page_extent_head(page0, len);
3074 uptodate = PageUptodate(page0);
3075 } else {
3076 i = 0;
3077 }
3078 for (; i < num_pages; i++, index++) {
3079 p = find_or_create_page(mapping, index, GFP_NOFS);
3080 if (!p) {
3081 WARN_ON(1);
3082 goto free_eb;
3083 }
3084 set_page_extent_mapped(p);
3085 mark_page_accessed(p);
3086 if (i == 0) {
3087 eb->first_page = p;
3088 set_page_extent_head(p, len);
3089 } else {
3090 set_page_private(p, EXTENT_PAGE_PRIVATE);
3091 }
3092 if (!PageUptodate(p))
3093 uptodate = 0;
3094
3095 /*
3096 * see below about how we avoid a nasty race with release page
3097 * and why we unlock later
3098 */
3099 if (i != 0)
3100 unlock_page(p);
3101 }
3102 if (uptodate)
3103 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3104
3105 ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
3106 if (ret)
3107 goto free_eb;
3108
3109 spin_lock(&tree->buffer_lock);
3110 ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
3111 if (ret == -EEXIST) {
3112 exists = radix_tree_lookup(&tree->buffer,
3113 start >> PAGE_CACHE_SHIFT);
3114 /* add one reference for the caller */
3115 atomic_inc(&exists->refs);
3116 spin_unlock(&tree->buffer_lock);
3117 radix_tree_preload_end();
3118 goto free_eb;
3119 }
3120 /* add one reference for the tree */
3121 atomic_inc(&eb->refs);
3122 spin_unlock(&tree->buffer_lock);
3123 radix_tree_preload_end();
3124
3125 /*
3126 * there is a race where release page may have
3127 * tried to find this extent buffer in the radix
3128 * but failed. It will tell the VM it is safe to
3129 * reclaim the, and it will clear the page private bit.
3130 * We must make sure to set the page private bit properly
3131 * after the extent buffer is in the radix tree so
3132 * it doesn't get lost
3133 */
3134 set_page_extent_mapped(eb->first_page);
3135 set_page_extent_head(eb->first_page, eb->len);
3136 if (!page0)
3137 unlock_page(eb->first_page);
3138 return eb;
3139
3140free_eb:
3141 if (eb->first_page && !page0)
3142 unlock_page(eb->first_page);
3143
3144 if (!atomic_dec_and_test(&eb->refs))
3145 return exists;
3146 btrfs_release_extent_buffer(eb);
3147 return exists;
3148}
3149
3150struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
3151 u64 start, unsigned long len)
3152{
3153 struct extent_buffer *eb;
3154
3155 rcu_read_lock();
3156 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3157 if (eb && atomic_inc_not_zero(&eb->refs)) {
3158 rcu_read_unlock();
3159 mark_page_accessed(eb->first_page);
3160 return eb;
3161 }
3162 rcu_read_unlock();
3163
3164 return NULL;
3165}
3166
3167void free_extent_buffer(struct extent_buffer *eb)
3168{
3169 if (!eb)
3170 return;
3171
3172 if (!atomic_dec_and_test(&eb->refs))
3173 return;
3174
3175 WARN_ON(1);
3176}
3177
3178int clear_extent_buffer_dirty(struct extent_io_tree *tree,
3179 struct extent_buffer *eb)
3180{
3181 unsigned long i;
3182 unsigned long num_pages;
3183 struct page *page;
3184
3185 num_pages = num_extent_pages(eb->start, eb->len);
3186
3187 for (i = 0; i < num_pages; i++) {
3188 page = extent_buffer_page(eb, i);
3189 if (!PageDirty(page))
3190 continue;
3191
3192 lock_page(page);
3193 WARN_ON(!PagePrivate(page));
3194
3195 set_page_extent_mapped(page);
3196 if (i == 0)
3197 set_page_extent_head(page, eb->len);
3198
3199 clear_page_dirty_for_io(page);
3200 spin_lock_irq(&page->mapping->tree_lock);
3201 if (!PageDirty(page)) {
3202 radix_tree_tag_clear(&page->mapping->page_tree,
3203 page_index(page),
3204 PAGECACHE_TAG_DIRTY);
3205 }
3206 spin_unlock_irq(&page->mapping->tree_lock);
3207 unlock_page(page);
3208 }
3209 return 0;
3210}
3211
3212int set_extent_buffer_dirty(struct extent_io_tree *tree,
3213 struct extent_buffer *eb)
3214{
3215 unsigned long i;
3216 unsigned long num_pages;
3217 int was_dirty = 0;
3218
3219 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
3220 num_pages = num_extent_pages(eb->start, eb->len);
3221 for (i = 0; i < num_pages; i++)
3222 __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3223 return was_dirty;
3224}
3225
3226static int __eb_straddles_pages(u64 start, u64 len)
3227{
3228 if (len < PAGE_CACHE_SIZE)
3229 return 1;
3230 if (start & (PAGE_CACHE_SIZE - 1))
3231 return 1;
3232 if ((start + len) & (PAGE_CACHE_SIZE - 1))
3233 return 1;
3234 return 0;
3235}
3236
3237static int eb_straddles_pages(struct extent_buffer *eb)
3238{
3239 return __eb_straddles_pages(eb->start, eb->len);
3240}
3241
3242int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3243 struct extent_buffer *eb,
3244 struct extent_state **cached_state)
3245{
3246 unsigned long i;
3247 struct page *page;
3248 unsigned long num_pages;
3249
3250 num_pages = num_extent_pages(eb->start, eb->len);
3251 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3252
3253 if (eb_straddles_pages(eb)) {
3254 clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3255 cached_state, GFP_NOFS);
3256 }
3257 for (i = 0; i < num_pages; i++) {
3258 page = extent_buffer_page(eb, i);
3259 if (page)
3260 ClearPageUptodate(page);
3261 }
3262 return 0;
3263}
3264
3265int set_extent_buffer_uptodate(struct extent_io_tree *tree,
3266 struct extent_buffer *eb)
3267{
3268 unsigned long i;
3269 struct page *page;
3270 unsigned long num_pages;
3271
3272 num_pages = num_extent_pages(eb->start, eb->len);
3273
3274 if (eb_straddles_pages(eb)) {
3275 set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3276 NULL, GFP_NOFS);
3277 }
3278 for (i = 0; i < num_pages; i++) {
3279 page = extent_buffer_page(eb, i);
3280 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3281 ((i == num_pages - 1) &&
3282 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3283 check_page_uptodate(tree, page);
3284 continue;
3285 }
3286 SetPageUptodate(page);
3287 }
3288 return 0;
3289}
3290
3291int extent_range_uptodate(struct extent_io_tree *tree,
3292 u64 start, u64 end)
3293{
3294 struct page *page;
3295 int ret;
3296 int pg_uptodate = 1;
3297 int uptodate;
3298 unsigned long index;
3299
3300 if (__eb_straddles_pages(start, end - start + 1)) {
3301 ret = test_range_bit(tree, start, end,
3302 EXTENT_UPTODATE, 1, NULL);
3303 if (ret)
3304 return 1;
3305 }
3306 while (start <= end) {
3307 index = start >> PAGE_CACHE_SHIFT;
3308 page = find_get_page(tree->mapping, index);
3309 uptodate = PageUptodate(page);
3310 page_cache_release(page);
3311 if (!uptodate) {
3312 pg_uptodate = 0;
3313 break;
3314 }
3315 start += PAGE_CACHE_SIZE;
3316 }
3317 return pg_uptodate;
3318}
3319
3320int extent_buffer_uptodate(struct extent_io_tree *tree,
3321 struct extent_buffer *eb,
3322 struct extent_state *cached_state)
3323{
3324 int ret = 0;
3325 unsigned long num_pages;
3326 unsigned long i;
3327 struct page *page;
3328 int pg_uptodate = 1;
3329
3330 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3331 return 1;
3332
3333 if (eb_straddles_pages(eb)) {
3334 ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3335 EXTENT_UPTODATE, 1, cached_state);
3336 if (ret)
3337 return ret;
3338 }
3339
3340 num_pages = num_extent_pages(eb->start, eb->len);
3341 for (i = 0; i < num_pages; i++) {
3342 page = extent_buffer_page(eb, i);
3343 if (!PageUptodate(page)) {
3344 pg_uptodate = 0;
3345 break;
3346 }
3347 }
3348 return pg_uptodate;
3349}
3350
3351int read_extent_buffer_pages(struct extent_io_tree *tree,
3352 struct extent_buffer *eb,
3353 u64 start, int wait,
3354 get_extent_t *get_extent, int mirror_num)
3355{
3356 unsigned long i;
3357 unsigned long start_i;
3358 struct page *page;
3359 int err;
3360 int ret = 0;
3361 int locked_pages = 0;
3362 int all_uptodate = 1;
3363 int inc_all_pages = 0;
3364 unsigned long num_pages;
3365 struct bio *bio = NULL;
3366 unsigned long bio_flags = 0;
3367
3368 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3369 return 0;
3370
3371 if (eb_straddles_pages(eb)) {
3372 if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3373 EXTENT_UPTODATE, 1, NULL)) {
3374 return 0;
3375 }
3376 }
3377
3378 if (start) {
3379 WARN_ON(start < eb->start);
3380 start_i = (start >> PAGE_CACHE_SHIFT) -
3381 (eb->start >> PAGE_CACHE_SHIFT);
3382 } else {
3383 start_i = 0;
3384 }
3385
3386 num_pages = num_extent_pages(eb->start, eb->len);
3387 for (i = start_i; i < num_pages; i++) {
3388 page = extent_buffer_page(eb, i);
3389 if (!wait) {
3390 if (!trylock_page(page))
3391 goto unlock_exit;
3392 } else {
3393 lock_page(page);
3394 }
3395 locked_pages++;
3396 if (!PageUptodate(page))
3397 all_uptodate = 0;
3398 }
3399 if (all_uptodate) {
3400 if (start_i == 0)
3401 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3402 goto unlock_exit;
3403 }
3404
3405 for (i = start_i; i < num_pages; i++) {
3406 page = extent_buffer_page(eb, i);
3407
3408 WARN_ON(!PagePrivate(page));
3409
3410 set_page_extent_mapped(page);
3411 if (i == 0)
3412 set_page_extent_head(page, eb->len);
3413
3414 if (inc_all_pages)
3415 page_cache_get(page);
3416 if (!PageUptodate(page)) {
3417 if (start_i == 0)
3418 inc_all_pages = 1;
3419 ClearPageError(page);
3420 err = __extent_read_full_page(tree, page,
3421 get_extent, &bio,
3422 mirror_num, &bio_flags);
3423 if (err)
3424 ret = err;
3425 } else {
3426 unlock_page(page);
3427 }
3428 }
3429
3430 if (bio)
3431 submit_one_bio(READ, bio, mirror_num, bio_flags);
3432
3433 if (ret || !wait)
3434 return ret;
3435
3436 for (i = start_i; i < num_pages; i++) {
3437 page = extent_buffer_page(eb, i);
3438 wait_on_page_locked(page);
3439 if (!PageUptodate(page))
3440 ret = -EIO;
3441 }
3442
3443 if (!ret)
3444 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3445 return ret;
3446
3447unlock_exit:
3448 i = start_i;
3449 while (locked_pages > 0) {
3450 page = extent_buffer_page(eb, i);
3451 i++;
3452 unlock_page(page);
3453 locked_pages--;
3454 }
3455 return ret;
3456}
3457
3458void read_extent_buffer(struct extent_buffer *eb, void *dstv,
3459 unsigned long start,
3460 unsigned long len)
3461{
3462 size_t cur;
3463 size_t offset;
3464 struct page *page;
3465 char *kaddr;
3466 char *dst = (char *)dstv;
3467 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3468 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3469
3470 WARN_ON(start > eb->len);
3471 WARN_ON(start + len > eb->start + eb->len);
3472
3473 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3474
3475 while (len > 0) {
3476 page = extent_buffer_page(eb, i);
3477
3478 cur = min(len, (PAGE_CACHE_SIZE - offset));
3479 kaddr = page_address(page);
3480 memcpy(dst, kaddr + offset, cur);
3481
3482 dst += cur;
3483 len -= cur;
3484 offset = 0;
3485 i++;
3486 }
3487}
3488
3489int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
3490 unsigned long min_len, char **map,
3491 unsigned long *map_start,
3492 unsigned long *map_len)
3493{
3494 size_t offset = start & (PAGE_CACHE_SIZE - 1);
3495 char *kaddr;
3496 struct page *p;
3497 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3498 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3499 unsigned long end_i = (start_offset + start + min_len - 1) >>
3500 PAGE_CACHE_SHIFT;
3501
3502 if (i != end_i)
3503 return -EINVAL;
3504
3505 if (i == 0) {
3506 offset = start_offset;
3507 *map_start = 0;
3508 } else {
3509 offset = 0;
3510 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
3511 }
3512
3513 if (start + min_len > eb->len) {
3514 printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
3515 "wanted %lu %lu\n", (unsigned long long)eb->start,
3516 eb->len, start, min_len);
3517 WARN_ON(1);
3518 return -EINVAL;
3519 }
3520
3521 p = extent_buffer_page(eb, i);
3522 kaddr = page_address(p);
3523 *map = kaddr + offset;
3524 *map_len = PAGE_CACHE_SIZE - offset;
3525 return 0;
3526}
3527
3528int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
3529 unsigned long start,
3530 unsigned long len)
3531{
3532 size_t cur;
3533 size_t offset;
3534 struct page *page;
3535 char *kaddr;
3536 char *ptr = (char *)ptrv;
3537 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3538 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3539 int ret = 0;
3540
3541 WARN_ON(start > eb->len);
3542 WARN_ON(start + len > eb->start + eb->len);
3543
3544 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3545
3546 while (len > 0) {
3547 page = extent_buffer_page(eb, i);
3548
3549 cur = min(len, (PAGE_CACHE_SIZE - offset));
3550
3551 kaddr = page_address(page);
3552 ret = memcmp(ptr, kaddr + offset, cur);
3553 if (ret)
3554 break;
3555
3556 ptr += cur;
3557 len -= cur;
3558 offset = 0;
3559 i++;
3560 }
3561 return ret;
3562}
3563
3564void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
3565 unsigned long start, unsigned long len)
3566{
3567 size_t cur;
3568 size_t offset;
3569 struct page *page;
3570 char *kaddr;
3571 char *src = (char *)srcv;
3572 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3573 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3574
3575 WARN_ON(start > eb->len);
3576 WARN_ON(start + len > eb->start + eb->len);
3577
3578 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3579
3580 while (len > 0) {
3581 page = extent_buffer_page(eb, i);
3582 WARN_ON(!PageUptodate(page));
3583
3584 cur = min(len, PAGE_CACHE_SIZE - offset);
3585 kaddr = page_address(page);
3586 memcpy(kaddr + offset, src, cur);
3587
3588 src += cur;
3589 len -= cur;
3590 offset = 0;
3591 i++;
3592 }
3593}
3594
3595void memset_extent_buffer(struct extent_buffer *eb, char c,
3596 unsigned long start, unsigned long len)
3597{
3598 size_t cur;
3599 size_t offset;
3600 struct page *page;
3601 char *kaddr;
3602 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3603 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3604
3605 WARN_ON(start > eb->len);
3606 WARN_ON(start + len > eb->start + eb->len);
3607
3608 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3609
3610 while (len > 0) {
3611 page = extent_buffer_page(eb, i);
3612 WARN_ON(!PageUptodate(page));
3613
3614 cur = min(len, PAGE_CACHE_SIZE - offset);
3615 kaddr = page_address(page);
3616 memset(kaddr + offset, c, cur);
3617
3618 len -= cur;
3619 offset = 0;
3620 i++;
3621 }
3622}
3623
3624void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
3625 unsigned long dst_offset, unsigned long src_offset,
3626 unsigned long len)
3627{
3628 u64 dst_len = dst->len;
3629 size_t cur;
3630 size_t offset;
3631 struct page *page;
3632 char *kaddr;
3633 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3634 unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3635
3636 WARN_ON(src->len != dst_len);
3637
3638 offset = (start_offset + dst_offset) &
3639 ((unsigned long)PAGE_CACHE_SIZE - 1);
3640
3641 while (len > 0) {
3642 page = extent_buffer_page(dst, i);
3643 WARN_ON(!PageUptodate(page));
3644
3645 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
3646
3647 kaddr = page_address(page);
3648 read_extent_buffer(src, kaddr + offset, src_offset, cur);
3649
3650 src_offset += cur;
3651 len -= cur;
3652 offset = 0;
3653 i++;
3654 }
3655}
3656
3657static void move_pages(struct page *dst_page, struct page *src_page,
3658 unsigned long dst_off, unsigned long src_off,
3659 unsigned long len)
3660{
3661 char *dst_kaddr = page_address(dst_page);
3662 if (dst_page == src_page) {
3663 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
3664 } else {
3665 char *src_kaddr = page_address(src_page);
3666 char *p = dst_kaddr + dst_off + len;
3667 char *s = src_kaddr + src_off + len;
3668
3669 while (len--)
3670 *--p = *--s;
3671 }
3672}
3673
3674static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
3675{
3676 unsigned long distance = (src > dst) ? src - dst : dst - src;
3677 return distance < len;
3678}
3679
3680static void copy_pages(struct page *dst_page, struct page *src_page,
3681 unsigned long dst_off, unsigned long src_off,
3682 unsigned long len)
3683{
3684 char *dst_kaddr = page_address(dst_page);
3685 char *src_kaddr;
3686
3687 if (dst_page != src_page) {
3688 src_kaddr = page_address(src_page);
3689 } else {
3690 src_kaddr = dst_kaddr;
3691 BUG_ON(areas_overlap(src_off, dst_off, len));
3692 }
3693
3694 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
3695}
3696
3697void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3698 unsigned long src_offset, unsigned long len)
3699{
3700 size_t cur;
3701 size_t dst_off_in_page;
3702 size_t src_off_in_page;
3703 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3704 unsigned long dst_i;
3705 unsigned long src_i;
3706
3707 if (src_offset + len > dst->len) {
3708 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3709 "len %lu dst len %lu\n", src_offset, len, dst->len);
3710 BUG_ON(1);
3711 }
3712 if (dst_offset + len > dst->len) {
3713 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3714 "len %lu dst len %lu\n", dst_offset, len, dst->len);
3715 BUG_ON(1);
3716 }
3717
3718 while (len > 0) {
3719 dst_off_in_page = (start_offset + dst_offset) &
3720 ((unsigned long)PAGE_CACHE_SIZE - 1);
3721 src_off_in_page = (start_offset + src_offset) &
3722 ((unsigned long)PAGE_CACHE_SIZE - 1);
3723
3724 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3725 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
3726
3727 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
3728 src_off_in_page));
3729 cur = min_t(unsigned long, cur,
3730 (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
3731
3732 copy_pages(extent_buffer_page(dst, dst_i),
3733 extent_buffer_page(dst, src_i),
3734 dst_off_in_page, src_off_in_page, cur);
3735
3736 src_offset += cur;
3737 dst_offset += cur;
3738 len -= cur;
3739 }
3740}
3741
3742void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3743 unsigned long src_offset, unsigned long len)
3744{
3745 size_t cur;
3746 size_t dst_off_in_page;
3747 size_t src_off_in_page;
3748 unsigned long dst_end = dst_offset + len - 1;
3749 unsigned long src_end = src_offset + len - 1;
3750 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3751 unsigned long dst_i;
3752 unsigned long src_i;
3753
3754 if (src_offset + len > dst->len) {
3755 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3756 "len %lu len %lu\n", src_offset, len, dst->len);
3757 BUG_ON(1);
3758 }
3759 if (dst_offset + len > dst->len) {
3760 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3761 "len %lu len %lu\n", dst_offset, len, dst->len);
3762 BUG_ON(1);
3763 }
3764 if (!areas_overlap(src_offset, dst_offset, len)) {
3765 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
3766 return;
3767 }
3768 while (len > 0) {
3769 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
3770 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
3771
3772 dst_off_in_page = (start_offset + dst_end) &
3773 ((unsigned long)PAGE_CACHE_SIZE - 1);
3774 src_off_in_page = (start_offset + src_end) &
3775 ((unsigned long)PAGE_CACHE_SIZE - 1);
3776
3777 cur = min_t(unsigned long, len, src_off_in_page + 1);
3778 cur = min(cur, dst_off_in_page + 1);
3779 move_pages(extent_buffer_page(dst, dst_i),
3780 extent_buffer_page(dst, src_i),
3781 dst_off_in_page - cur + 1,
3782 src_off_in_page - cur + 1, cur);
3783
3784 dst_end -= cur;
3785 src_end -= cur;
3786 len -= cur;
3787 }
3788}
3789
3790static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
3791{
3792 struct extent_buffer *eb =
3793 container_of(head, struct extent_buffer, rcu_head);
3794
3795 btrfs_release_extent_buffer(eb);
3796}
3797
3798int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
3799{
3800 u64 start = page_offset(page);
3801 struct extent_buffer *eb;
3802 int ret = 1;
3803
3804 spin_lock(&tree->buffer_lock);
3805 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3806 if (!eb) {
3807 spin_unlock(&tree->buffer_lock);
3808 return ret;
3809 }
3810
3811 if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3812 ret = 0;
3813 goto out;
3814 }
3815
3816 /*
3817 * set @eb->refs to 0 if it is already 1, and then release the @eb.
3818 * Or go back.
3819 */
3820 if (atomic_cmpxchg(&eb->refs, 1, 0) != 1) {
3821 ret = 0;
3822 goto out;
3823 }
3824
3825 radix_tree_delete(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3826out:
3827 spin_unlock(&tree->buffer_lock);
3828
3829 /* at this point we can safely release the extent buffer */
3830 if (atomic_read(&eb->refs) == 0)
3831 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
3832 return ret;
3833}