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-rw-r--r--fs/btrfs/extent_io.c3717
1 files changed, 3717 insertions, 0 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
new file mode 100644
index 000000000000..e086d407f1fa
--- /dev/null
+++ b/fs/btrfs/extent_io.c
@@ -0,0 +1,3717 @@
1#include <linux/bitops.h>
2#include <linux/slab.h>
3#include <linux/bio.h>
4#include <linux/mm.h>
5#include <linux/gfp.h>
6#include <linux/pagemap.h>
7#include <linux/page-flags.h>
8#include <linux/module.h>
9#include <linux/spinlock.h>
10#include <linux/blkdev.h>
11#include <linux/swap.h>
12#include <linux/version.h>
13#include <linux/writeback.h>
14#include <linux/pagevec.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
21/* temporary define until extent_map moves out of btrfs */
22struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
23 unsigned long extra_flags,
24 void (*ctor)(void *, struct kmem_cache *,
25 unsigned long));
26
27static struct kmem_cache *extent_state_cache;
28static struct kmem_cache *extent_buffer_cache;
29
30static LIST_HEAD(buffers);
31static LIST_HEAD(states);
32
33#define LEAK_DEBUG 0
34#ifdef LEAK_DEBUG
35static DEFINE_SPINLOCK(leak_lock);
36#endif
37
38#define BUFFER_LRU_MAX 64
39
40struct tree_entry {
41 u64 start;
42 u64 end;
43 struct rb_node rb_node;
44};
45
46struct extent_page_data {
47 struct bio *bio;
48 struct extent_io_tree *tree;
49 get_extent_t *get_extent;
50
51 /* tells writepage not to lock the state bits for this range
52 * it still does the unlocking
53 */
54 int extent_locked;
55};
56
57int __init extent_io_init(void)
58{
59 extent_state_cache = btrfs_cache_create("extent_state",
60 sizeof(struct extent_state), 0,
61 NULL);
62 if (!extent_state_cache)
63 return -ENOMEM;
64
65 extent_buffer_cache = btrfs_cache_create("extent_buffers",
66 sizeof(struct extent_buffer), 0,
67 NULL);
68 if (!extent_buffer_cache)
69 goto free_state_cache;
70 return 0;
71
72free_state_cache:
73 kmem_cache_destroy(extent_state_cache);
74 return -ENOMEM;
75}
76
77void extent_io_exit(void)
78{
79 struct extent_state *state;
80 struct extent_buffer *eb;
81
82 while (!list_empty(&states)) {
83 state = list_entry(states.next, struct extent_state, leak_list);
84 printk(KERN_ERR "btrfs state leak: start %llu end %llu "
85 "state %lu in tree %p refs %d\n",
86 (unsigned long long)state->start,
87 (unsigned long long)state->end,
88 state->state, state->tree, atomic_read(&state->refs));
89 list_del(&state->leak_list);
90 kmem_cache_free(extent_state_cache, state);
91
92 }
93
94 while (!list_empty(&buffers)) {
95 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
96 printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
97 "refs %d\n", (unsigned long long)eb->start,
98 eb->len, atomic_read(&eb->refs));
99 list_del(&eb->leak_list);
100 kmem_cache_free(extent_buffer_cache, eb);
101 }
102 if (extent_state_cache)
103 kmem_cache_destroy(extent_state_cache);
104 if (extent_buffer_cache)
105 kmem_cache_destroy(extent_buffer_cache);
106}
107
108void extent_io_tree_init(struct extent_io_tree *tree,
109 struct address_space *mapping, gfp_t mask)
110{
111 tree->state.rb_node = NULL;
112 tree->buffer.rb_node = NULL;
113 tree->ops = NULL;
114 tree->dirty_bytes = 0;
115 spin_lock_init(&tree->lock);
116 spin_lock_init(&tree->buffer_lock);
117 tree->mapping = mapping;
118}
119
120static struct extent_state *alloc_extent_state(gfp_t mask)
121{
122 struct extent_state *state;
123#ifdef LEAK_DEBUG
124 unsigned long flags;
125#endif
126
127 state = kmem_cache_alloc(extent_state_cache, mask);
128 if (!state)
129 return state;
130 state->state = 0;
131 state->private = 0;
132 state->tree = NULL;
133#ifdef LEAK_DEBUG
134 spin_lock_irqsave(&leak_lock, flags);
135 list_add(&state->leak_list, &states);
136 spin_unlock_irqrestore(&leak_lock, flags);
137#endif
138 atomic_set(&state->refs, 1);
139 init_waitqueue_head(&state->wq);
140 return state;
141}
142
143static void free_extent_state(struct extent_state *state)
144{
145 if (!state)
146 return;
147 if (atomic_dec_and_test(&state->refs)) {
148#ifdef LEAK_DEBUG
149 unsigned long flags;
150#endif
151 WARN_ON(state->tree);
152#ifdef LEAK_DEBUG
153 spin_lock_irqsave(&leak_lock, flags);
154 list_del(&state->leak_list);
155 spin_unlock_irqrestore(&leak_lock, flags);
156#endif
157 kmem_cache_free(extent_state_cache, state);
158 }
159}
160
161static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
162 struct rb_node *node)
163{
164 struct rb_node **p = &root->rb_node;
165 struct rb_node *parent = NULL;
166 struct tree_entry *entry;
167
168 while (*p) {
169 parent = *p;
170 entry = rb_entry(parent, struct tree_entry, rb_node);
171
172 if (offset < entry->start)
173 p = &(*p)->rb_left;
174 else if (offset > entry->end)
175 p = &(*p)->rb_right;
176 else
177 return parent;
178 }
179
180 entry = rb_entry(node, struct tree_entry, rb_node);
181 rb_link_node(node, parent, p);
182 rb_insert_color(node, root);
183 return NULL;
184}
185
186static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
187 struct rb_node **prev_ret,
188 struct rb_node **next_ret)
189{
190 struct rb_root *root = &tree->state;
191 struct rb_node *n = root->rb_node;
192 struct rb_node *prev = NULL;
193 struct rb_node *orig_prev = NULL;
194 struct tree_entry *entry;
195 struct tree_entry *prev_entry = NULL;
196
197 while (n) {
198 entry = rb_entry(n, struct tree_entry, rb_node);
199 prev = n;
200 prev_entry = entry;
201
202 if (offset < entry->start)
203 n = n->rb_left;
204 else if (offset > entry->end)
205 n = n->rb_right;
206 else
207 return n;
208 }
209
210 if (prev_ret) {
211 orig_prev = prev;
212 while (prev && offset > prev_entry->end) {
213 prev = rb_next(prev);
214 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
215 }
216 *prev_ret = prev;
217 prev = orig_prev;
218 }
219
220 if (next_ret) {
221 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
222 while (prev && offset < prev_entry->start) {
223 prev = rb_prev(prev);
224 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
225 }
226 *next_ret = prev;
227 }
228 return NULL;
229}
230
231static inline struct rb_node *tree_search(struct extent_io_tree *tree,
232 u64 offset)
233{
234 struct rb_node *prev = NULL;
235 struct rb_node *ret;
236
237 ret = __etree_search(tree, offset, &prev, NULL);
238 if (!ret)
239 return prev;
240 return ret;
241}
242
243static struct extent_buffer *buffer_tree_insert(struct extent_io_tree *tree,
244 u64 offset, struct rb_node *node)
245{
246 struct rb_root *root = &tree->buffer;
247 struct rb_node **p = &root->rb_node;
248 struct rb_node *parent = NULL;
249 struct extent_buffer *eb;
250
251 while (*p) {
252 parent = *p;
253 eb = rb_entry(parent, struct extent_buffer, rb_node);
254
255 if (offset < eb->start)
256 p = &(*p)->rb_left;
257 else if (offset > eb->start)
258 p = &(*p)->rb_right;
259 else
260 return eb;
261 }
262
263 rb_link_node(node, parent, p);
264 rb_insert_color(node, root);
265 return NULL;
266}
267
268static struct extent_buffer *buffer_search(struct extent_io_tree *tree,
269 u64 offset)
270{
271 struct rb_root *root = &tree->buffer;
272 struct rb_node *n = root->rb_node;
273 struct extent_buffer *eb;
274
275 while (n) {
276 eb = rb_entry(n, struct extent_buffer, rb_node);
277 if (offset < eb->start)
278 n = n->rb_left;
279 else if (offset > eb->start)
280 n = n->rb_right;
281 else
282 return eb;
283 }
284 return NULL;
285}
286
287/*
288 * utility function to look for merge candidates inside a given range.
289 * Any extents with matching state are merged together into a single
290 * extent in the tree. Extents with EXTENT_IO in their state field
291 * are not merged because the end_io handlers need to be able to do
292 * operations on them without sleeping (or doing allocations/splits).
293 *
294 * This should be called with the tree lock held.
295 */
296static int merge_state(struct extent_io_tree *tree,
297 struct extent_state *state)
298{
299 struct extent_state *other;
300 struct rb_node *other_node;
301
302 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
303 return 0;
304
305 other_node = rb_prev(&state->rb_node);
306 if (other_node) {
307 other = rb_entry(other_node, struct extent_state, rb_node);
308 if (other->end == state->start - 1 &&
309 other->state == state->state) {
310 state->start = other->start;
311 other->tree = NULL;
312 rb_erase(&other->rb_node, &tree->state);
313 free_extent_state(other);
314 }
315 }
316 other_node = rb_next(&state->rb_node);
317 if (other_node) {
318 other = rb_entry(other_node, struct extent_state, rb_node);
319 if (other->start == state->end + 1 &&
320 other->state == state->state) {
321 other->start = state->start;
322 state->tree = NULL;
323 rb_erase(&state->rb_node, &tree->state);
324 free_extent_state(state);
325 }
326 }
327 return 0;
328}
329
330static void set_state_cb(struct extent_io_tree *tree,
331 struct extent_state *state,
332 unsigned long bits)
333{
334 if (tree->ops && tree->ops->set_bit_hook) {
335 tree->ops->set_bit_hook(tree->mapping->host, state->start,
336 state->end, state->state, bits);
337 }
338}
339
340static void clear_state_cb(struct extent_io_tree *tree,
341 struct extent_state *state,
342 unsigned long bits)
343{
344 if (tree->ops && tree->ops->clear_bit_hook) {
345 tree->ops->clear_bit_hook(tree->mapping->host, state->start,
346 state->end, state->state, bits);
347 }
348}
349
350/*
351 * insert an extent_state struct into the tree. 'bits' are set on the
352 * struct before it is inserted.
353 *
354 * This may return -EEXIST if the extent is already there, in which case the
355 * state struct is freed.
356 *
357 * The tree lock is not taken internally. This is a utility function and
358 * probably isn't what you want to call (see set/clear_extent_bit).
359 */
360static int insert_state(struct extent_io_tree *tree,
361 struct extent_state *state, u64 start, u64 end,
362 int bits)
363{
364 struct rb_node *node;
365
366 if (end < start) {
367 printk(KERN_ERR "btrfs end < start %llu %llu\n",
368 (unsigned long long)end,
369 (unsigned long long)start);
370 WARN_ON(1);
371 }
372 if (bits & EXTENT_DIRTY)
373 tree->dirty_bytes += end - start + 1;
374 set_state_cb(tree, state, bits);
375 state->state |= bits;
376 state->start = start;
377 state->end = end;
378 node = tree_insert(&tree->state, end, &state->rb_node);
379 if (node) {
380 struct extent_state *found;
381 found = rb_entry(node, struct extent_state, rb_node);
382 printk(KERN_ERR "btrfs found node %llu %llu on insert of "
383 "%llu %llu\n", (unsigned long long)found->start,
384 (unsigned long long)found->end,
385 (unsigned long long)start, (unsigned long long)end);
386 free_extent_state(state);
387 return -EEXIST;
388 }
389 state->tree = tree;
390 merge_state(tree, state);
391 return 0;
392}
393
394/*
395 * split a given extent state struct in two, inserting the preallocated
396 * struct 'prealloc' as the newly created second half. 'split' indicates an
397 * offset inside 'orig' where it should be split.
398 *
399 * Before calling,
400 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
401 * are two extent state structs in the tree:
402 * prealloc: [orig->start, split - 1]
403 * orig: [ split, orig->end ]
404 *
405 * The tree locks are not taken by this function. They need to be held
406 * by the caller.
407 */
408static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
409 struct extent_state *prealloc, u64 split)
410{
411 struct rb_node *node;
412 prealloc->start = orig->start;
413 prealloc->end = split - 1;
414 prealloc->state = orig->state;
415 orig->start = split;
416
417 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
418 if (node) {
419 struct extent_state *found;
420 found = rb_entry(node, struct extent_state, rb_node);
421 free_extent_state(prealloc);
422 return -EEXIST;
423 }
424 prealloc->tree = tree;
425 return 0;
426}
427
428/*
429 * utility function to clear some bits in an extent state struct.
430 * it will optionally wake up any one waiting on this state (wake == 1), or
431 * forcibly remove the state from the tree (delete == 1).
432 *
433 * If no bits are set on the state struct after clearing things, the
434 * struct is freed and removed from the tree
435 */
436static int clear_state_bit(struct extent_io_tree *tree,
437 struct extent_state *state, int bits, int wake,
438 int delete)
439{
440 int ret = state->state & bits;
441
442 if ((bits & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
443 u64 range = state->end - state->start + 1;
444 WARN_ON(range > tree->dirty_bytes);
445 tree->dirty_bytes -= range;
446 }
447 clear_state_cb(tree, state, bits);
448 state->state &= ~bits;
449 if (wake)
450 wake_up(&state->wq);
451 if (delete || state->state == 0) {
452 if (state->tree) {
453 clear_state_cb(tree, state, state->state);
454 rb_erase(&state->rb_node, &tree->state);
455 state->tree = NULL;
456 free_extent_state(state);
457 } else {
458 WARN_ON(1);
459 }
460 } else {
461 merge_state(tree, state);
462 }
463 return ret;
464}
465
466/*
467 * clear some bits on a range in the tree. This may require splitting
468 * or inserting elements in the tree, so the gfp mask is used to
469 * indicate which allocations or sleeping are allowed.
470 *
471 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
472 * the given range from the tree regardless of state (ie for truncate).
473 *
474 * the range [start, end] is inclusive.
475 *
476 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
477 * bits were already set, or zero if none of the bits were already set.
478 */
479int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
480 int bits, int wake, int delete, gfp_t mask)
481{
482 struct extent_state *state;
483 struct extent_state *prealloc = NULL;
484 struct rb_node *node;
485 int err;
486 int set = 0;
487
488again:
489 if (!prealloc && (mask & __GFP_WAIT)) {
490 prealloc = alloc_extent_state(mask);
491 if (!prealloc)
492 return -ENOMEM;
493 }
494
495 spin_lock(&tree->lock);
496 /*
497 * this search will find the extents that end after
498 * our range starts
499 */
500 node = tree_search(tree, start);
501 if (!node)
502 goto out;
503 state = rb_entry(node, struct extent_state, rb_node);
504 if (state->start > end)
505 goto out;
506 WARN_ON(state->end < start);
507
508 /*
509 * | ---- desired range ---- |
510 * | state | or
511 * | ------------- state -------------- |
512 *
513 * We need to split the extent we found, and may flip
514 * bits on second half.
515 *
516 * If the extent we found extends past our range, we
517 * just split and search again. It'll get split again
518 * the next time though.
519 *
520 * If the extent we found is inside our range, we clear
521 * the desired bit on it.
522 */
523
524 if (state->start < start) {
525 if (!prealloc)
526 prealloc = alloc_extent_state(GFP_ATOMIC);
527 err = split_state(tree, state, prealloc, start);
528 BUG_ON(err == -EEXIST);
529 prealloc = NULL;
530 if (err)
531 goto out;
532 if (state->end <= end) {
533 start = state->end + 1;
534 set |= clear_state_bit(tree, state, bits,
535 wake, delete);
536 } else {
537 start = state->start;
538 }
539 goto search_again;
540 }
541 /*
542 * | ---- desired range ---- |
543 * | state |
544 * We need to split the extent, and clear the bit
545 * on the first half
546 */
547 if (state->start <= end && state->end > end) {
548 if (!prealloc)
549 prealloc = alloc_extent_state(GFP_ATOMIC);
550 err = split_state(tree, state, prealloc, end + 1);
551 BUG_ON(err == -EEXIST);
552
553 if (wake)
554 wake_up(&state->wq);
555 set |= clear_state_bit(tree, prealloc, bits,
556 wake, delete);
557 prealloc = NULL;
558 goto out;
559 }
560
561 start = state->end + 1;
562 set |= clear_state_bit(tree, state, bits, wake, delete);
563 goto search_again;
564
565out:
566 spin_unlock(&tree->lock);
567 if (prealloc)
568 free_extent_state(prealloc);
569
570 return set;
571
572search_again:
573 if (start > end)
574 goto out;
575 spin_unlock(&tree->lock);
576 if (mask & __GFP_WAIT)
577 cond_resched();
578 goto again;
579}
580
581static int wait_on_state(struct extent_io_tree *tree,
582 struct extent_state *state)
583 __releases(tree->lock)
584 __acquires(tree->lock)
585{
586 DEFINE_WAIT(wait);
587 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
588 spin_unlock(&tree->lock);
589 schedule();
590 spin_lock(&tree->lock);
591 finish_wait(&state->wq, &wait);
592 return 0;
593}
594
595/*
596 * waits for one or more bits to clear on a range in the state tree.
597 * The range [start, end] is inclusive.
598 * The tree lock is taken by this function
599 */
600int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
601{
602 struct extent_state *state;
603 struct rb_node *node;
604
605 spin_lock(&tree->lock);
606again:
607 while (1) {
608 /*
609 * this search will find all the extents that end after
610 * our range starts
611 */
612 node = tree_search(tree, start);
613 if (!node)
614 break;
615
616 state = rb_entry(node, struct extent_state, rb_node);
617
618 if (state->start > end)
619 goto out;
620
621 if (state->state & bits) {
622 start = state->start;
623 atomic_inc(&state->refs);
624 wait_on_state(tree, state);
625 free_extent_state(state);
626 goto again;
627 }
628 start = state->end + 1;
629
630 if (start > end)
631 break;
632
633 if (need_resched()) {
634 spin_unlock(&tree->lock);
635 cond_resched();
636 spin_lock(&tree->lock);
637 }
638 }
639out:
640 spin_unlock(&tree->lock);
641 return 0;
642}
643
644static void set_state_bits(struct extent_io_tree *tree,
645 struct extent_state *state,
646 int bits)
647{
648 if ((bits & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
649 u64 range = state->end - state->start + 1;
650 tree->dirty_bytes += range;
651 }
652 set_state_cb(tree, state, bits);
653 state->state |= bits;
654}
655
656/*
657 * set some bits on a range in the tree. This may require allocations
658 * or sleeping, so the gfp mask is used to indicate what is allowed.
659 *
660 * If 'exclusive' == 1, this will fail with -EEXIST if some part of the
661 * range already has the desired bits set. The start of the existing
662 * range is returned in failed_start in this case.
663 *
664 * [start, end] is inclusive
665 * This takes the tree lock.
666 */
667static int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
668 int bits, int exclusive, u64 *failed_start,
669 gfp_t mask)
670{
671 struct extent_state *state;
672 struct extent_state *prealloc = NULL;
673 struct rb_node *node;
674 int err = 0;
675 int set;
676 u64 last_start;
677 u64 last_end;
678again:
679 if (!prealloc && (mask & __GFP_WAIT)) {
680 prealloc = alloc_extent_state(mask);
681 if (!prealloc)
682 return -ENOMEM;
683 }
684
685 spin_lock(&tree->lock);
686 /*
687 * this search will find all the extents that end after
688 * our range starts.
689 */
690 node = tree_search(tree, start);
691 if (!node) {
692 err = insert_state(tree, prealloc, start, end, bits);
693 prealloc = NULL;
694 BUG_ON(err == -EEXIST);
695 goto out;
696 }
697
698 state = rb_entry(node, struct extent_state, rb_node);
699 last_start = state->start;
700 last_end = state->end;
701
702 /*
703 * | ---- desired range ---- |
704 * | state |
705 *
706 * Just lock what we found and keep going
707 */
708 if (state->start == start && state->end <= end) {
709 set = state->state & bits;
710 if (set && exclusive) {
711 *failed_start = state->start;
712 err = -EEXIST;
713 goto out;
714 }
715 set_state_bits(tree, state, bits);
716 start = state->end + 1;
717 merge_state(tree, state);
718 goto search_again;
719 }
720
721 /*
722 * | ---- desired range ---- |
723 * | state |
724 * or
725 * | ------------- state -------------- |
726 *
727 * We need to split the extent we found, and may flip bits on
728 * second half.
729 *
730 * If the extent we found extends past our
731 * range, we just split and search again. It'll get split
732 * again the next time though.
733 *
734 * If the extent we found is inside our range, we set the
735 * desired bit on it.
736 */
737 if (state->start < start) {
738 set = state->state & bits;
739 if (exclusive && set) {
740 *failed_start = start;
741 err = -EEXIST;
742 goto out;
743 }
744 err = split_state(tree, state, prealloc, start);
745 BUG_ON(err == -EEXIST);
746 prealloc = NULL;
747 if (err)
748 goto out;
749 if (state->end <= end) {
750 set_state_bits(tree, state, bits);
751 start = state->end + 1;
752 merge_state(tree, state);
753 } else {
754 start = state->start;
755 }
756 goto search_again;
757 }
758 /*
759 * | ---- desired range ---- |
760 * | state | or | state |
761 *
762 * There's a hole, we need to insert something in it and
763 * ignore the extent we found.
764 */
765 if (state->start > start) {
766 u64 this_end;
767 if (end < last_start)
768 this_end = end;
769 else
770 this_end = last_start - 1;
771 err = insert_state(tree, prealloc, start, this_end,
772 bits);
773 prealloc = NULL;
774 BUG_ON(err == -EEXIST);
775 if (err)
776 goto out;
777 start = this_end + 1;
778 goto search_again;
779 }
780 /*
781 * | ---- desired range ---- |
782 * | state |
783 * We need to split the extent, and set the bit
784 * on the first half
785 */
786 if (state->start <= end && state->end > end) {
787 set = state->state & bits;
788 if (exclusive && set) {
789 *failed_start = start;
790 err = -EEXIST;
791 goto out;
792 }
793 err = split_state(tree, state, prealloc, end + 1);
794 BUG_ON(err == -EEXIST);
795
796 set_state_bits(tree, prealloc, bits);
797 merge_state(tree, prealloc);
798 prealloc = NULL;
799 goto out;
800 }
801
802 goto search_again;
803
804out:
805 spin_unlock(&tree->lock);
806 if (prealloc)
807 free_extent_state(prealloc);
808
809 return err;
810
811search_again:
812 if (start > end)
813 goto out;
814 spin_unlock(&tree->lock);
815 if (mask & __GFP_WAIT)
816 cond_resched();
817 goto again;
818}
819
820/* wrappers around set/clear extent bit */
821int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
822 gfp_t mask)
823{
824 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
825 mask);
826}
827
828int set_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
829 gfp_t mask)
830{
831 return set_extent_bit(tree, start, end, EXTENT_ORDERED, 0, NULL, mask);
832}
833
834int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
835 int bits, gfp_t mask)
836{
837 return set_extent_bit(tree, start, end, bits, 0, NULL,
838 mask);
839}
840
841int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
842 int bits, gfp_t mask)
843{
844 return clear_extent_bit(tree, start, end, bits, 0, 0, mask);
845}
846
847int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
848 gfp_t mask)
849{
850 return set_extent_bit(tree, start, end,
851 EXTENT_DELALLOC | EXTENT_DIRTY,
852 0, NULL, mask);
853}
854
855int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
856 gfp_t mask)
857{
858 return clear_extent_bit(tree, start, end,
859 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, mask);
860}
861
862int clear_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
863 gfp_t mask)
864{
865 return clear_extent_bit(tree, start, end, EXTENT_ORDERED, 1, 0, mask);
866}
867
868int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
869 gfp_t mask)
870{
871 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
872 mask);
873}
874
875static int clear_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
876 gfp_t mask)
877{
878 return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask);
879}
880
881int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
882 gfp_t mask)
883{
884 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
885 mask);
886}
887
888static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
889 u64 end, gfp_t mask)
890{
891 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask);
892}
893
894static int set_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
895 gfp_t mask)
896{
897 return set_extent_bit(tree, start, end, EXTENT_WRITEBACK,
898 0, NULL, mask);
899}
900
901static int clear_extent_writeback(struct extent_io_tree *tree, u64 start,
902 u64 end, gfp_t mask)
903{
904 return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask);
905}
906
907int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end)
908{
909 return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
910}
911
912/*
913 * either insert or lock state struct between start and end use mask to tell
914 * us if waiting is desired.
915 */
916int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
917{
918 int err;
919 u64 failed_start;
920 while (1) {
921 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
922 &failed_start, mask);
923 if (err == -EEXIST && (mask & __GFP_WAIT)) {
924 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
925 start = failed_start;
926 } else {
927 break;
928 }
929 WARN_ON(start > end);
930 }
931 return err;
932}
933
934int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
935 gfp_t mask)
936{
937 int err;
938 u64 failed_start;
939
940 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
941 &failed_start, mask);
942 if (err == -EEXIST) {
943 if (failed_start > start)
944 clear_extent_bit(tree, start, failed_start - 1,
945 EXTENT_LOCKED, 1, 0, mask);
946 return 0;
947 }
948 return 1;
949}
950
951int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end,
952 gfp_t mask)
953{
954 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask);
955}
956
957/*
958 * helper function to set pages and extents in the tree dirty
959 */
960int set_range_dirty(struct extent_io_tree *tree, u64 start, u64 end)
961{
962 unsigned long index = start >> PAGE_CACHE_SHIFT;
963 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
964 struct page *page;
965
966 while (index <= end_index) {
967 page = find_get_page(tree->mapping, index);
968 BUG_ON(!page);
969 __set_page_dirty_nobuffers(page);
970 page_cache_release(page);
971 index++;
972 }
973 set_extent_dirty(tree, start, end, GFP_NOFS);
974 return 0;
975}
976
977/*
978 * helper function to set both pages and extents in the tree writeback
979 */
980static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
981{
982 unsigned long index = start >> PAGE_CACHE_SHIFT;
983 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
984 struct page *page;
985
986 while (index <= end_index) {
987 page = find_get_page(tree->mapping, index);
988 BUG_ON(!page);
989 set_page_writeback(page);
990 page_cache_release(page);
991 index++;
992 }
993 set_extent_writeback(tree, start, end, GFP_NOFS);
994 return 0;
995}
996
997/*
998 * find the first offset in the io tree with 'bits' set. zero is
999 * returned if we find something, and *start_ret and *end_ret are
1000 * set to reflect the state struct that was found.
1001 *
1002 * If nothing was found, 1 is returned, < 0 on error
1003 */
1004int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1005 u64 *start_ret, u64 *end_ret, int bits)
1006{
1007 struct rb_node *node;
1008 struct extent_state *state;
1009 int ret = 1;
1010
1011 spin_lock(&tree->lock);
1012 /*
1013 * this search will find all the extents that end after
1014 * our range starts.
1015 */
1016 node = tree_search(tree, start);
1017 if (!node)
1018 goto out;
1019
1020 while (1) {
1021 state = rb_entry(node, struct extent_state, rb_node);
1022 if (state->end >= start && (state->state & bits)) {
1023 *start_ret = state->start;
1024 *end_ret = state->end;
1025 ret = 0;
1026 break;
1027 }
1028 node = rb_next(node);
1029 if (!node)
1030 break;
1031 }
1032out:
1033 spin_unlock(&tree->lock);
1034 return ret;
1035}
1036
1037/* find the first state struct with 'bits' set after 'start', and
1038 * return it. tree->lock must be held. NULL will returned if
1039 * nothing was found after 'start'
1040 */
1041struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
1042 u64 start, int bits)
1043{
1044 struct rb_node *node;
1045 struct extent_state *state;
1046
1047 /*
1048 * this search will find all the extents that end after
1049 * our range starts.
1050 */
1051 node = tree_search(tree, start);
1052 if (!node)
1053 goto out;
1054
1055 while (1) {
1056 state = rb_entry(node, struct extent_state, rb_node);
1057 if (state->end >= start && (state->state & bits))
1058 return state;
1059
1060 node = rb_next(node);
1061 if (!node)
1062 break;
1063 }
1064out:
1065 return NULL;
1066}
1067
1068/*
1069 * find a contiguous range of bytes in the file marked as delalloc, not
1070 * more than 'max_bytes'. start and end are used to return the range,
1071 *
1072 * 1 is returned if we find something, 0 if nothing was in the tree
1073 */
1074static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1075 u64 *start, u64 *end, u64 max_bytes)
1076{
1077 struct rb_node *node;
1078 struct extent_state *state;
1079 u64 cur_start = *start;
1080 u64 found = 0;
1081 u64 total_bytes = 0;
1082
1083 spin_lock(&tree->lock);
1084
1085 /*
1086 * this search will find all the extents that end after
1087 * our range starts.
1088 */
1089 node = tree_search(tree, cur_start);
1090 if (!node) {
1091 if (!found)
1092 *end = (u64)-1;
1093 goto out;
1094 }
1095
1096 while (1) {
1097 state = rb_entry(node, struct extent_state, rb_node);
1098 if (found && (state->start != cur_start ||
1099 (state->state & EXTENT_BOUNDARY))) {
1100 goto out;
1101 }
1102 if (!(state->state & EXTENT_DELALLOC)) {
1103 if (!found)
1104 *end = state->end;
1105 goto out;
1106 }
1107 if (!found)
1108 *start = state->start;
1109 found++;
1110 *end = state->end;
1111 cur_start = state->end + 1;
1112 node = rb_next(node);
1113 if (!node)
1114 break;
1115 total_bytes += state->end - state->start + 1;
1116 if (total_bytes >= max_bytes)
1117 break;
1118 }
1119out:
1120 spin_unlock(&tree->lock);
1121 return found;
1122}
1123
1124static noinline int __unlock_for_delalloc(struct inode *inode,
1125 struct page *locked_page,
1126 u64 start, u64 end)
1127{
1128 int ret;
1129 struct page *pages[16];
1130 unsigned long index = start >> PAGE_CACHE_SHIFT;
1131 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1132 unsigned long nr_pages = end_index - index + 1;
1133 int i;
1134
1135 if (index == locked_page->index && end_index == index)
1136 return 0;
1137
1138 while (nr_pages > 0) {
1139 ret = find_get_pages_contig(inode->i_mapping, index,
1140 min_t(unsigned long, nr_pages,
1141 ARRAY_SIZE(pages)), pages);
1142 for (i = 0; i < ret; i++) {
1143 if (pages[i] != locked_page)
1144 unlock_page(pages[i]);
1145 page_cache_release(pages[i]);
1146 }
1147 nr_pages -= ret;
1148 index += ret;
1149 cond_resched();
1150 }
1151 return 0;
1152}
1153
1154static noinline int lock_delalloc_pages(struct inode *inode,
1155 struct page *locked_page,
1156 u64 delalloc_start,
1157 u64 delalloc_end)
1158{
1159 unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
1160 unsigned long start_index = index;
1161 unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
1162 unsigned long pages_locked = 0;
1163 struct page *pages[16];
1164 unsigned long nrpages;
1165 int ret;
1166 int i;
1167
1168 /* the caller is responsible for locking the start index */
1169 if (index == locked_page->index && index == end_index)
1170 return 0;
1171
1172 /* skip the page at the start index */
1173 nrpages = end_index - index + 1;
1174 while (nrpages > 0) {
1175 ret = find_get_pages_contig(inode->i_mapping, index,
1176 min_t(unsigned long,
1177 nrpages, ARRAY_SIZE(pages)), pages);
1178 if (ret == 0) {
1179 ret = -EAGAIN;
1180 goto done;
1181 }
1182 /* now we have an array of pages, lock them all */
1183 for (i = 0; i < ret; i++) {
1184 /*
1185 * the caller is taking responsibility for
1186 * locked_page
1187 */
1188 if (pages[i] != locked_page) {
1189 lock_page(pages[i]);
1190 if (!PageDirty(pages[i]) ||
1191 pages[i]->mapping != inode->i_mapping) {
1192 ret = -EAGAIN;
1193 unlock_page(pages[i]);
1194 page_cache_release(pages[i]);
1195 goto done;
1196 }
1197 }
1198 page_cache_release(pages[i]);
1199 pages_locked++;
1200 }
1201 nrpages -= ret;
1202 index += ret;
1203 cond_resched();
1204 }
1205 ret = 0;
1206done:
1207 if (ret && pages_locked) {
1208 __unlock_for_delalloc(inode, locked_page,
1209 delalloc_start,
1210 ((u64)(start_index + pages_locked - 1)) <<
1211 PAGE_CACHE_SHIFT);
1212 }
1213 return ret;
1214}
1215
1216/*
1217 * find a contiguous range of bytes in the file marked as delalloc, not
1218 * more than 'max_bytes'. start and end are used to return the range,
1219 *
1220 * 1 is returned if we find something, 0 if nothing was in the tree
1221 */
1222static noinline u64 find_lock_delalloc_range(struct inode *inode,
1223 struct extent_io_tree *tree,
1224 struct page *locked_page,
1225 u64 *start, u64 *end,
1226 u64 max_bytes)
1227{
1228 u64 delalloc_start;
1229 u64 delalloc_end;
1230 u64 found;
1231 int ret;
1232 int loops = 0;
1233
1234again:
1235 /* step one, find a bunch of delalloc bytes starting at start */
1236 delalloc_start = *start;
1237 delalloc_end = 0;
1238 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1239 max_bytes);
1240 if (!found || delalloc_end <= *start) {
1241 *start = delalloc_start;
1242 *end = delalloc_end;
1243 return found;
1244 }
1245
1246 /*
1247 * start comes from the offset of locked_page. We have to lock
1248 * pages in order, so we can't process delalloc bytes before
1249 * locked_page
1250 */
1251 if (delalloc_start < *start)
1252 delalloc_start = *start;
1253
1254 /*
1255 * make sure to limit the number of pages we try to lock down
1256 * if we're looping.
1257 */
1258 if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1259 delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
1260
1261 /* step two, lock all the pages after the page that has start */
1262 ret = lock_delalloc_pages(inode, locked_page,
1263 delalloc_start, delalloc_end);
1264 if (ret == -EAGAIN) {
1265 /* some of the pages are gone, lets avoid looping by
1266 * shortening the size of the delalloc range we're searching
1267 */
1268 if (!loops) {
1269 unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
1270 max_bytes = PAGE_CACHE_SIZE - offset;
1271 loops = 1;
1272 goto again;
1273 } else {
1274 found = 0;
1275 goto out_failed;
1276 }
1277 }
1278 BUG_ON(ret);
1279
1280 /* step three, lock the state bits for the whole range */
1281 lock_extent(tree, delalloc_start, delalloc_end, GFP_NOFS);
1282
1283 /* then test to make sure it is all still delalloc */
1284 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1285 EXTENT_DELALLOC, 1);
1286 if (!ret) {
1287 unlock_extent(tree, delalloc_start, delalloc_end, GFP_NOFS);
1288 __unlock_for_delalloc(inode, locked_page,
1289 delalloc_start, delalloc_end);
1290 cond_resched();
1291 goto again;
1292 }
1293 *start = delalloc_start;
1294 *end = delalloc_end;
1295out_failed:
1296 return found;
1297}
1298
1299int extent_clear_unlock_delalloc(struct inode *inode,
1300 struct extent_io_tree *tree,
1301 u64 start, u64 end, struct page *locked_page,
1302 int unlock_pages,
1303 int clear_unlock,
1304 int clear_delalloc, int clear_dirty,
1305 int set_writeback,
1306 int end_writeback)
1307{
1308 int ret;
1309 struct page *pages[16];
1310 unsigned long index = start >> PAGE_CACHE_SHIFT;
1311 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1312 unsigned long nr_pages = end_index - index + 1;
1313 int i;
1314 int clear_bits = 0;
1315
1316 if (clear_unlock)
1317 clear_bits |= EXTENT_LOCKED;
1318 if (clear_dirty)
1319 clear_bits |= EXTENT_DIRTY;
1320
1321 if (clear_delalloc)
1322 clear_bits |= EXTENT_DELALLOC;
1323
1324 clear_extent_bit(tree, start, end, clear_bits, 1, 0, GFP_NOFS);
1325 if (!(unlock_pages || clear_dirty || set_writeback || end_writeback))
1326 return 0;
1327
1328 while (nr_pages > 0) {
1329 ret = find_get_pages_contig(inode->i_mapping, index,
1330 min_t(unsigned long,
1331 nr_pages, ARRAY_SIZE(pages)), pages);
1332 for (i = 0; i < ret; i++) {
1333 if (pages[i] == locked_page) {
1334 page_cache_release(pages[i]);
1335 continue;
1336 }
1337 if (clear_dirty)
1338 clear_page_dirty_for_io(pages[i]);
1339 if (set_writeback)
1340 set_page_writeback(pages[i]);
1341 if (end_writeback)
1342 end_page_writeback(pages[i]);
1343 if (unlock_pages)
1344 unlock_page(pages[i]);
1345 page_cache_release(pages[i]);
1346 }
1347 nr_pages -= ret;
1348 index += ret;
1349 cond_resched();
1350 }
1351 return 0;
1352}
1353
1354/*
1355 * count the number of bytes in the tree that have a given bit(s)
1356 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1357 * cached. The total number found is returned.
1358 */
1359u64 count_range_bits(struct extent_io_tree *tree,
1360 u64 *start, u64 search_end, u64 max_bytes,
1361 unsigned long bits)
1362{
1363 struct rb_node *node;
1364 struct extent_state *state;
1365 u64 cur_start = *start;
1366 u64 total_bytes = 0;
1367 int found = 0;
1368
1369 if (search_end <= cur_start) {
1370 WARN_ON(1);
1371 return 0;
1372 }
1373
1374 spin_lock(&tree->lock);
1375 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1376 total_bytes = tree->dirty_bytes;
1377 goto out;
1378 }
1379 /*
1380 * this search will find all the extents that end after
1381 * our range starts.
1382 */
1383 node = tree_search(tree, cur_start);
1384 if (!node)
1385 goto out;
1386
1387 while (1) {
1388 state = rb_entry(node, struct extent_state, rb_node);
1389 if (state->start > search_end)
1390 break;
1391 if (state->end >= cur_start && (state->state & bits)) {
1392 total_bytes += min(search_end, state->end) + 1 -
1393 max(cur_start, state->start);
1394 if (total_bytes >= max_bytes)
1395 break;
1396 if (!found) {
1397 *start = state->start;
1398 found = 1;
1399 }
1400 }
1401 node = rb_next(node);
1402 if (!node)
1403 break;
1404 }
1405out:
1406 spin_unlock(&tree->lock);
1407 return total_bytes;
1408}
1409
1410#if 0
1411/*
1412 * helper function to lock both pages and extents in the tree.
1413 * pages must be locked first.
1414 */
1415static int lock_range(struct extent_io_tree *tree, u64 start, u64 end)
1416{
1417 unsigned long index = start >> PAGE_CACHE_SHIFT;
1418 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1419 struct page *page;
1420 int err;
1421
1422 while (index <= end_index) {
1423 page = grab_cache_page(tree->mapping, index);
1424 if (!page) {
1425 err = -ENOMEM;
1426 goto failed;
1427 }
1428 if (IS_ERR(page)) {
1429 err = PTR_ERR(page);
1430 goto failed;
1431 }
1432 index++;
1433 }
1434 lock_extent(tree, start, end, GFP_NOFS);
1435 return 0;
1436
1437failed:
1438 /*
1439 * we failed above in getting the page at 'index', so we undo here
1440 * up to but not including the page at 'index'
1441 */
1442 end_index = index;
1443 index = start >> PAGE_CACHE_SHIFT;
1444 while (index < end_index) {
1445 page = find_get_page(tree->mapping, index);
1446 unlock_page(page);
1447 page_cache_release(page);
1448 index++;
1449 }
1450 return err;
1451}
1452
1453/*
1454 * helper function to unlock both pages and extents in the tree.
1455 */
1456static int unlock_range(struct extent_io_tree *tree, u64 start, u64 end)
1457{
1458 unsigned long index = start >> PAGE_CACHE_SHIFT;
1459 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1460 struct page *page;
1461
1462 while (index <= end_index) {
1463 page = find_get_page(tree->mapping, index);
1464 unlock_page(page);
1465 page_cache_release(page);
1466 index++;
1467 }
1468 unlock_extent(tree, start, end, GFP_NOFS);
1469 return 0;
1470}
1471#endif
1472
1473/*
1474 * set the private field for a given byte offset in the tree. If there isn't
1475 * an extent_state there already, this does nothing.
1476 */
1477int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1478{
1479 struct rb_node *node;
1480 struct extent_state *state;
1481 int ret = 0;
1482
1483 spin_lock(&tree->lock);
1484 /*
1485 * this search will find all the extents that end after
1486 * our range starts.
1487 */
1488 node = tree_search(tree, start);
1489 if (!node) {
1490 ret = -ENOENT;
1491 goto out;
1492 }
1493 state = rb_entry(node, struct extent_state, rb_node);
1494 if (state->start != start) {
1495 ret = -ENOENT;
1496 goto out;
1497 }
1498 state->private = private;
1499out:
1500 spin_unlock(&tree->lock);
1501 return ret;
1502}
1503
1504int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1505{
1506 struct rb_node *node;
1507 struct extent_state *state;
1508 int ret = 0;
1509
1510 spin_lock(&tree->lock);
1511 /*
1512 * this search will find all the extents that end after
1513 * our range starts.
1514 */
1515 node = tree_search(tree, start);
1516 if (!node) {
1517 ret = -ENOENT;
1518 goto out;
1519 }
1520 state = rb_entry(node, struct extent_state, rb_node);
1521 if (state->start != start) {
1522 ret = -ENOENT;
1523 goto out;
1524 }
1525 *private = state->private;
1526out:
1527 spin_unlock(&tree->lock);
1528 return ret;
1529}
1530
1531/*
1532 * searches a range in the state tree for a given mask.
1533 * If 'filled' == 1, this returns 1 only if every extent in the tree
1534 * has the bits set. Otherwise, 1 is returned if any bit in the
1535 * range is found set.
1536 */
1537int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1538 int bits, int filled)
1539{
1540 struct extent_state *state = NULL;
1541 struct rb_node *node;
1542 int bitset = 0;
1543
1544 spin_lock(&tree->lock);
1545 node = tree_search(tree, start);
1546 while (node && start <= end) {
1547 state = rb_entry(node, struct extent_state, rb_node);
1548
1549 if (filled && state->start > start) {
1550 bitset = 0;
1551 break;
1552 }
1553
1554 if (state->start > end)
1555 break;
1556
1557 if (state->state & bits) {
1558 bitset = 1;
1559 if (!filled)
1560 break;
1561 } else if (filled) {
1562 bitset = 0;
1563 break;
1564 }
1565 start = state->end + 1;
1566 if (start > end)
1567 break;
1568 node = rb_next(node);
1569 if (!node) {
1570 if (filled)
1571 bitset = 0;
1572 break;
1573 }
1574 }
1575 spin_unlock(&tree->lock);
1576 return bitset;
1577}
1578
1579/*
1580 * helper function to set a given page up to date if all the
1581 * extents in the tree for that page are up to date
1582 */
1583static int check_page_uptodate(struct extent_io_tree *tree,
1584 struct page *page)
1585{
1586 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1587 u64 end = start + PAGE_CACHE_SIZE - 1;
1588 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1))
1589 SetPageUptodate(page);
1590 return 0;
1591}
1592
1593/*
1594 * helper function to unlock a page if all the extents in the tree
1595 * for that page are unlocked
1596 */
1597static int check_page_locked(struct extent_io_tree *tree,
1598 struct page *page)
1599{
1600 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1601 u64 end = start + PAGE_CACHE_SIZE - 1;
1602 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0))
1603 unlock_page(page);
1604 return 0;
1605}
1606
1607/*
1608 * helper function to end page writeback if all the extents
1609 * in the tree for that page are done with writeback
1610 */
1611static int check_page_writeback(struct extent_io_tree *tree,
1612 struct page *page)
1613{
1614 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1615 u64 end = start + PAGE_CACHE_SIZE - 1;
1616 if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0))
1617 end_page_writeback(page);
1618 return 0;
1619}
1620
1621/* lots and lots of room for performance fixes in the end_bio funcs */
1622
1623/*
1624 * after a writepage IO is done, we need to:
1625 * clear the uptodate bits on error
1626 * clear the writeback bits in the extent tree for this IO
1627 * end_page_writeback if the page has no more pending IO
1628 *
1629 * Scheduling is not allowed, so the extent state tree is expected
1630 * to have one and only one object corresponding to this IO.
1631 */
1632static void end_bio_extent_writepage(struct bio *bio, int err)
1633{
1634 int uptodate = err == 0;
1635 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1636 struct extent_io_tree *tree;
1637 u64 start;
1638 u64 end;
1639 int whole_page;
1640 int ret;
1641
1642 do {
1643 struct page *page = bvec->bv_page;
1644 tree = &BTRFS_I(page->mapping->host)->io_tree;
1645
1646 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1647 bvec->bv_offset;
1648 end = start + bvec->bv_len - 1;
1649
1650 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1651 whole_page = 1;
1652 else
1653 whole_page = 0;
1654
1655 if (--bvec >= bio->bi_io_vec)
1656 prefetchw(&bvec->bv_page->flags);
1657 if (tree->ops && tree->ops->writepage_end_io_hook) {
1658 ret = tree->ops->writepage_end_io_hook(page, start,
1659 end, NULL, uptodate);
1660 if (ret)
1661 uptodate = 0;
1662 }
1663
1664 if (!uptodate && tree->ops &&
1665 tree->ops->writepage_io_failed_hook) {
1666 ret = tree->ops->writepage_io_failed_hook(bio, page,
1667 start, end, NULL);
1668 if (ret == 0) {
1669 uptodate = (err == 0);
1670 continue;
1671 }
1672 }
1673
1674 if (!uptodate) {
1675 clear_extent_uptodate(tree, start, end, GFP_ATOMIC);
1676 ClearPageUptodate(page);
1677 SetPageError(page);
1678 }
1679
1680 clear_extent_writeback(tree, start, end, GFP_ATOMIC);
1681
1682 if (whole_page)
1683 end_page_writeback(page);
1684 else
1685 check_page_writeback(tree, page);
1686 } while (bvec >= bio->bi_io_vec);
1687
1688 bio_put(bio);
1689}
1690
1691/*
1692 * after a readpage IO is done, we need to:
1693 * clear the uptodate bits on error
1694 * set the uptodate bits if things worked
1695 * set the page up to date if all extents in the tree are uptodate
1696 * clear the lock bit in the extent tree
1697 * unlock the page if there are no other extents locked for it
1698 *
1699 * Scheduling is not allowed, so the extent state tree is expected
1700 * to have one and only one object corresponding to this IO.
1701 */
1702static void end_bio_extent_readpage(struct bio *bio, int err)
1703{
1704 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1705 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1706 struct extent_io_tree *tree;
1707 u64 start;
1708 u64 end;
1709 int whole_page;
1710 int ret;
1711
1712 if (err)
1713 uptodate = 0;
1714
1715 do {
1716 struct page *page = bvec->bv_page;
1717 tree = &BTRFS_I(page->mapping->host)->io_tree;
1718
1719 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1720 bvec->bv_offset;
1721 end = start + bvec->bv_len - 1;
1722
1723 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1724 whole_page = 1;
1725 else
1726 whole_page = 0;
1727
1728 if (--bvec >= bio->bi_io_vec)
1729 prefetchw(&bvec->bv_page->flags);
1730
1731 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1732 ret = tree->ops->readpage_end_io_hook(page, start, end,
1733 NULL);
1734 if (ret)
1735 uptodate = 0;
1736 }
1737 if (!uptodate && tree->ops &&
1738 tree->ops->readpage_io_failed_hook) {
1739 ret = tree->ops->readpage_io_failed_hook(bio, page,
1740 start, end, NULL);
1741 if (ret == 0) {
1742 uptodate =
1743 test_bit(BIO_UPTODATE, &bio->bi_flags);
1744 if (err)
1745 uptodate = 0;
1746 continue;
1747 }
1748 }
1749
1750 if (uptodate) {
1751 set_extent_uptodate(tree, start, end,
1752 GFP_ATOMIC);
1753 }
1754 unlock_extent(tree, start, end, GFP_ATOMIC);
1755
1756 if (whole_page) {
1757 if (uptodate) {
1758 SetPageUptodate(page);
1759 } else {
1760 ClearPageUptodate(page);
1761 SetPageError(page);
1762 }
1763 unlock_page(page);
1764 } else {
1765 if (uptodate) {
1766 check_page_uptodate(tree, page);
1767 } else {
1768 ClearPageUptodate(page);
1769 SetPageError(page);
1770 }
1771 check_page_locked(tree, page);
1772 }
1773 } while (bvec >= bio->bi_io_vec);
1774
1775 bio_put(bio);
1776}
1777
1778/*
1779 * IO done from prepare_write is pretty simple, we just unlock
1780 * the structs in the extent tree when done, and set the uptodate bits
1781 * as appropriate.
1782 */
1783static void end_bio_extent_preparewrite(struct bio *bio, int err)
1784{
1785 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1786 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1787 struct extent_io_tree *tree;
1788 u64 start;
1789 u64 end;
1790
1791 do {
1792 struct page *page = bvec->bv_page;
1793 tree = &BTRFS_I(page->mapping->host)->io_tree;
1794
1795 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1796 bvec->bv_offset;
1797 end = start + bvec->bv_len - 1;
1798
1799 if (--bvec >= bio->bi_io_vec)
1800 prefetchw(&bvec->bv_page->flags);
1801
1802 if (uptodate) {
1803 set_extent_uptodate(tree, start, end, GFP_ATOMIC);
1804 } else {
1805 ClearPageUptodate(page);
1806 SetPageError(page);
1807 }
1808
1809 unlock_extent(tree, start, end, GFP_ATOMIC);
1810
1811 } while (bvec >= bio->bi_io_vec);
1812
1813 bio_put(bio);
1814}
1815
1816static struct bio *
1817extent_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
1818 gfp_t gfp_flags)
1819{
1820 struct bio *bio;
1821
1822 bio = bio_alloc(gfp_flags, nr_vecs);
1823
1824 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
1825 while (!bio && (nr_vecs /= 2))
1826 bio = bio_alloc(gfp_flags, nr_vecs);
1827 }
1828
1829 if (bio) {
1830 bio->bi_size = 0;
1831 bio->bi_bdev = bdev;
1832 bio->bi_sector = first_sector;
1833 }
1834 return bio;
1835}
1836
1837static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
1838 unsigned long bio_flags)
1839{
1840 int ret = 0;
1841 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1842 struct page *page = bvec->bv_page;
1843 struct extent_io_tree *tree = bio->bi_private;
1844 u64 start;
1845 u64 end;
1846
1847 start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1848 end = start + bvec->bv_len - 1;
1849
1850 bio->bi_private = NULL;
1851
1852 bio_get(bio);
1853
1854 if (tree->ops && tree->ops->submit_bio_hook)
1855 tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1856 mirror_num, bio_flags);
1857 else
1858 submit_bio(rw, bio);
1859 if (bio_flagged(bio, BIO_EOPNOTSUPP))
1860 ret = -EOPNOTSUPP;
1861 bio_put(bio);
1862 return ret;
1863}
1864
1865static int submit_extent_page(int rw, struct extent_io_tree *tree,
1866 struct page *page, sector_t sector,
1867 size_t size, unsigned long offset,
1868 struct block_device *bdev,
1869 struct bio **bio_ret,
1870 unsigned long max_pages,
1871 bio_end_io_t end_io_func,
1872 int mirror_num,
1873 unsigned long prev_bio_flags,
1874 unsigned long bio_flags)
1875{
1876 int ret = 0;
1877 struct bio *bio;
1878 int nr;
1879 int contig = 0;
1880 int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
1881 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
1882 size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
1883
1884 if (bio_ret && *bio_ret) {
1885 bio = *bio_ret;
1886 if (old_compressed)
1887 contig = bio->bi_sector == sector;
1888 else
1889 contig = bio->bi_sector + (bio->bi_size >> 9) ==
1890 sector;
1891
1892 if (prev_bio_flags != bio_flags || !contig ||
1893 (tree->ops && tree->ops->merge_bio_hook &&
1894 tree->ops->merge_bio_hook(page, offset, page_size, bio,
1895 bio_flags)) ||
1896 bio_add_page(bio, page, page_size, offset) < page_size) {
1897 ret = submit_one_bio(rw, bio, mirror_num,
1898 prev_bio_flags);
1899 bio = NULL;
1900 } else {
1901 return 0;
1902 }
1903 }
1904 if (this_compressed)
1905 nr = BIO_MAX_PAGES;
1906 else
1907 nr = bio_get_nr_vecs(bdev);
1908
1909 bio = extent_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1910
1911 bio_add_page(bio, page, page_size, offset);
1912 bio->bi_end_io = end_io_func;
1913 bio->bi_private = tree;
1914
1915 if (bio_ret)
1916 *bio_ret = bio;
1917 else
1918 ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
1919
1920 return ret;
1921}
1922
1923void set_page_extent_mapped(struct page *page)
1924{
1925 if (!PagePrivate(page)) {
1926 SetPagePrivate(page);
1927 page_cache_get(page);
1928 set_page_private(page, EXTENT_PAGE_PRIVATE);
1929 }
1930}
1931
1932static void set_page_extent_head(struct page *page, unsigned long len)
1933{
1934 set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
1935}
1936
1937/*
1938 * basic readpage implementation. Locked extent state structs are inserted
1939 * into the tree that are removed when the IO is done (by the end_io
1940 * handlers)
1941 */
1942static int __extent_read_full_page(struct extent_io_tree *tree,
1943 struct page *page,
1944 get_extent_t *get_extent,
1945 struct bio **bio, int mirror_num,
1946 unsigned long *bio_flags)
1947{
1948 struct inode *inode = page->mapping->host;
1949 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1950 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1951 u64 end;
1952 u64 cur = start;
1953 u64 extent_offset;
1954 u64 last_byte = i_size_read(inode);
1955 u64 block_start;
1956 u64 cur_end;
1957 sector_t sector;
1958 struct extent_map *em;
1959 struct block_device *bdev;
1960 int ret;
1961 int nr = 0;
1962 size_t page_offset = 0;
1963 size_t iosize;
1964 size_t disk_io_size;
1965 size_t blocksize = inode->i_sb->s_blocksize;
1966 unsigned long this_bio_flag = 0;
1967
1968 set_page_extent_mapped(page);
1969
1970 end = page_end;
1971 lock_extent(tree, start, end, GFP_NOFS);
1972
1973 if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
1974 char *userpage;
1975 size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
1976
1977 if (zero_offset) {
1978 iosize = PAGE_CACHE_SIZE - zero_offset;
1979 userpage = kmap_atomic(page, KM_USER0);
1980 memset(userpage + zero_offset, 0, iosize);
1981 flush_dcache_page(page);
1982 kunmap_atomic(userpage, KM_USER0);
1983 }
1984 }
1985 while (cur <= end) {
1986 if (cur >= last_byte) {
1987 char *userpage;
1988 iosize = PAGE_CACHE_SIZE - page_offset;
1989 userpage = kmap_atomic(page, KM_USER0);
1990 memset(userpage + page_offset, 0, iosize);
1991 flush_dcache_page(page);
1992 kunmap_atomic(userpage, KM_USER0);
1993 set_extent_uptodate(tree, cur, cur + iosize - 1,
1994 GFP_NOFS);
1995 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1996 break;
1997 }
1998 em = get_extent(inode, page, page_offset, cur,
1999 end - cur + 1, 0);
2000 if (IS_ERR(em) || !em) {
2001 SetPageError(page);
2002 unlock_extent(tree, cur, end, GFP_NOFS);
2003 break;
2004 }
2005 extent_offset = cur - em->start;
2006 BUG_ON(extent_map_end(em) <= cur);
2007 BUG_ON(end < cur);
2008
2009 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
2010 this_bio_flag = EXTENT_BIO_COMPRESSED;
2011
2012 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2013 cur_end = min(extent_map_end(em) - 1, end);
2014 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2015 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
2016 disk_io_size = em->block_len;
2017 sector = em->block_start >> 9;
2018 } else {
2019 sector = (em->block_start + extent_offset) >> 9;
2020 disk_io_size = iosize;
2021 }
2022 bdev = em->bdev;
2023 block_start = em->block_start;
2024 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2025 block_start = EXTENT_MAP_HOLE;
2026 free_extent_map(em);
2027 em = NULL;
2028
2029 /* we've found a hole, just zero and go on */
2030 if (block_start == EXTENT_MAP_HOLE) {
2031 char *userpage;
2032 userpage = kmap_atomic(page, KM_USER0);
2033 memset(userpage + page_offset, 0, iosize);
2034 flush_dcache_page(page);
2035 kunmap_atomic(userpage, KM_USER0);
2036
2037 set_extent_uptodate(tree, cur, cur + iosize - 1,
2038 GFP_NOFS);
2039 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2040 cur = cur + iosize;
2041 page_offset += iosize;
2042 continue;
2043 }
2044 /* the get_extent function already copied into the page */
2045 if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) {
2046 check_page_uptodate(tree, page);
2047 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2048 cur = cur + iosize;
2049 page_offset += iosize;
2050 continue;
2051 }
2052 /* we have an inline extent but it didn't get marked up
2053 * to date. Error out
2054 */
2055 if (block_start == EXTENT_MAP_INLINE) {
2056 SetPageError(page);
2057 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2058 cur = cur + iosize;
2059 page_offset += iosize;
2060 continue;
2061 }
2062
2063 ret = 0;
2064 if (tree->ops && tree->ops->readpage_io_hook) {
2065 ret = tree->ops->readpage_io_hook(page, cur,
2066 cur + iosize - 1);
2067 }
2068 if (!ret) {
2069 unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
2070 pnr -= page->index;
2071 ret = submit_extent_page(READ, tree, page,
2072 sector, disk_io_size, page_offset,
2073 bdev, bio, pnr,
2074 end_bio_extent_readpage, mirror_num,
2075 *bio_flags,
2076 this_bio_flag);
2077 nr++;
2078 *bio_flags = this_bio_flag;
2079 }
2080 if (ret)
2081 SetPageError(page);
2082 cur = cur + iosize;
2083 page_offset += iosize;
2084 }
2085 if (!nr) {
2086 if (!PageError(page))
2087 SetPageUptodate(page);
2088 unlock_page(page);
2089 }
2090 return 0;
2091}
2092
2093int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
2094 get_extent_t *get_extent)
2095{
2096 struct bio *bio = NULL;
2097 unsigned long bio_flags = 0;
2098 int ret;
2099
2100 ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
2101 &bio_flags);
2102 if (bio)
2103 submit_one_bio(READ, bio, 0, bio_flags);
2104 return ret;
2105}
2106
2107/*
2108 * the writepage semantics are similar to regular writepage. extent
2109 * records are inserted to lock ranges in the tree, and as dirty areas
2110 * are found, they are marked writeback. Then the lock bits are removed
2111 * and the end_io handler clears the writeback ranges
2112 */
2113static int __extent_writepage(struct page *page, struct writeback_control *wbc,
2114 void *data)
2115{
2116 struct inode *inode = page->mapping->host;
2117 struct extent_page_data *epd = data;
2118 struct extent_io_tree *tree = epd->tree;
2119 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2120 u64 delalloc_start;
2121 u64 page_end = start + PAGE_CACHE_SIZE - 1;
2122 u64 end;
2123 u64 cur = start;
2124 u64 extent_offset;
2125 u64 last_byte = i_size_read(inode);
2126 u64 block_start;
2127 u64 iosize;
2128 u64 unlock_start;
2129 sector_t sector;
2130 struct extent_map *em;
2131 struct block_device *bdev;
2132 int ret;
2133 int nr = 0;
2134 size_t pg_offset = 0;
2135 size_t blocksize;
2136 loff_t i_size = i_size_read(inode);
2137 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2138 u64 nr_delalloc;
2139 u64 delalloc_end;
2140 int page_started;
2141 int compressed;
2142 unsigned long nr_written = 0;
2143
2144 WARN_ON(!PageLocked(page));
2145 pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2146 if (page->index > end_index ||
2147 (page->index == end_index && !pg_offset)) {
2148 page->mapping->a_ops->invalidatepage(page, 0);
2149 unlock_page(page);
2150 return 0;
2151 }
2152
2153 if (page->index == end_index) {
2154 char *userpage;
2155
2156 userpage = kmap_atomic(page, KM_USER0);
2157 memset(userpage + pg_offset, 0,
2158 PAGE_CACHE_SIZE - pg_offset);
2159 kunmap_atomic(userpage, KM_USER0);
2160 flush_dcache_page(page);
2161 }
2162 pg_offset = 0;
2163
2164 set_page_extent_mapped(page);
2165
2166 delalloc_start = start;
2167 delalloc_end = 0;
2168 page_started = 0;
2169 if (!epd->extent_locked) {
2170 while (delalloc_end < page_end) {
2171 nr_delalloc = find_lock_delalloc_range(inode, tree,
2172 page,
2173 &delalloc_start,
2174 &delalloc_end,
2175 128 * 1024 * 1024);
2176 if (nr_delalloc == 0) {
2177 delalloc_start = delalloc_end + 1;
2178 continue;
2179 }
2180 tree->ops->fill_delalloc(inode, page, delalloc_start,
2181 delalloc_end, &page_started,
2182 &nr_written);
2183 delalloc_start = delalloc_end + 1;
2184 }
2185
2186 /* did the fill delalloc function already unlock and start
2187 * the IO?
2188 */
2189 if (page_started) {
2190 ret = 0;
2191 goto update_nr_written;
2192 }
2193 }
2194 lock_extent(tree, start, page_end, GFP_NOFS);
2195
2196 unlock_start = start;
2197
2198 if (tree->ops && tree->ops->writepage_start_hook) {
2199 ret = tree->ops->writepage_start_hook(page, start,
2200 page_end);
2201 if (ret == -EAGAIN) {
2202 unlock_extent(tree, start, page_end, GFP_NOFS);
2203 redirty_page_for_writepage(wbc, page);
2204 unlock_page(page);
2205 ret = 0;
2206 goto update_nr_written;
2207 }
2208 }
2209
2210 nr_written++;
2211
2212 end = page_end;
2213 if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0))
2214 printk(KERN_ERR "btrfs delalloc bits after lock_extent\n");
2215
2216 if (last_byte <= start) {
2217 clear_extent_dirty(tree, start, page_end, GFP_NOFS);
2218 unlock_extent(tree, start, page_end, GFP_NOFS);
2219 if (tree->ops && tree->ops->writepage_end_io_hook)
2220 tree->ops->writepage_end_io_hook(page, start,
2221 page_end, NULL, 1);
2222 unlock_start = page_end + 1;
2223 goto done;
2224 }
2225
2226 set_extent_uptodate(tree, start, page_end, GFP_NOFS);
2227 blocksize = inode->i_sb->s_blocksize;
2228
2229 while (cur <= end) {
2230 if (cur >= last_byte) {
2231 clear_extent_dirty(tree, cur, page_end, GFP_NOFS);
2232 unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
2233 if (tree->ops && tree->ops->writepage_end_io_hook)
2234 tree->ops->writepage_end_io_hook(page, cur,
2235 page_end, NULL, 1);
2236 unlock_start = page_end + 1;
2237 break;
2238 }
2239 em = epd->get_extent(inode, page, pg_offset, cur,
2240 end - cur + 1, 1);
2241 if (IS_ERR(em) || !em) {
2242 SetPageError(page);
2243 break;
2244 }
2245
2246 extent_offset = cur - em->start;
2247 BUG_ON(extent_map_end(em) <= cur);
2248 BUG_ON(end < cur);
2249 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2250 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2251 sector = (em->block_start + extent_offset) >> 9;
2252 bdev = em->bdev;
2253 block_start = em->block_start;
2254 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2255 free_extent_map(em);
2256 em = NULL;
2257
2258 /*
2259 * compressed and inline extents are written through other
2260 * paths in the FS
2261 */
2262 if (compressed || block_start == EXTENT_MAP_HOLE ||
2263 block_start == EXTENT_MAP_INLINE) {
2264 clear_extent_dirty(tree, cur,
2265 cur + iosize - 1, GFP_NOFS);
2266
2267 unlock_extent(tree, unlock_start, cur + iosize - 1,
2268 GFP_NOFS);
2269
2270 /*
2271 * end_io notification does not happen here for
2272 * compressed extents
2273 */
2274 if (!compressed && tree->ops &&
2275 tree->ops->writepage_end_io_hook)
2276 tree->ops->writepage_end_io_hook(page, cur,
2277 cur + iosize - 1,
2278 NULL, 1);
2279 else if (compressed) {
2280 /* we don't want to end_page_writeback on
2281 * a compressed extent. this happens
2282 * elsewhere
2283 */
2284 nr++;
2285 }
2286
2287 cur += iosize;
2288 pg_offset += iosize;
2289 unlock_start = cur;
2290 continue;
2291 }
2292 /* leave this out until we have a page_mkwrite call */
2293 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2294 EXTENT_DIRTY, 0)) {
2295 cur = cur + iosize;
2296 pg_offset += iosize;
2297 continue;
2298 }
2299
2300 clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS);
2301 if (tree->ops && tree->ops->writepage_io_hook) {
2302 ret = tree->ops->writepage_io_hook(page, cur,
2303 cur + iosize - 1);
2304 } else {
2305 ret = 0;
2306 }
2307 if (ret) {
2308 SetPageError(page);
2309 } else {
2310 unsigned long max_nr = end_index + 1;
2311
2312 set_range_writeback(tree, cur, cur + iosize - 1);
2313 if (!PageWriteback(page)) {
2314 printk(KERN_ERR "btrfs warning page %lu not "
2315 "writeback, cur %llu end %llu\n",
2316 page->index, (unsigned long long)cur,
2317 (unsigned long long)end);
2318 }
2319
2320 ret = submit_extent_page(WRITE, tree, page, sector,
2321 iosize, pg_offset, bdev,
2322 &epd->bio, max_nr,
2323 end_bio_extent_writepage,
2324 0, 0, 0);
2325 if (ret)
2326 SetPageError(page);
2327 }
2328 cur = cur + iosize;
2329 pg_offset += iosize;
2330 nr++;
2331 }
2332done:
2333 if (nr == 0) {
2334 /* make sure the mapping tag for page dirty gets cleared */
2335 set_page_writeback(page);
2336 end_page_writeback(page);
2337 }
2338 if (unlock_start <= page_end)
2339 unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
2340 unlock_page(page);
2341
2342update_nr_written:
2343 wbc->nr_to_write -= nr_written;
2344 if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
2345 wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
2346 page->mapping->writeback_index = page->index + nr_written;
2347 return 0;
2348}
2349
2350/**
2351 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
2352 * @mapping: address space structure to write
2353 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
2354 * @writepage: function called for each page
2355 * @data: data passed to writepage function
2356 *
2357 * If a page is already under I/O, write_cache_pages() skips it, even
2358 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
2359 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
2360 * and msync() need to guarantee that all the data which was dirty at the time
2361 * the call was made get new I/O started against them. If wbc->sync_mode is
2362 * WB_SYNC_ALL then we were called for data integrity and we must wait for
2363 * existing IO to complete.
2364 */
2365static int extent_write_cache_pages(struct extent_io_tree *tree,
2366 struct address_space *mapping,
2367 struct writeback_control *wbc,
2368 writepage_t writepage, void *data,
2369 void (*flush_fn)(void *))
2370{
2371 struct backing_dev_info *bdi = mapping->backing_dev_info;
2372 int ret = 0;
2373 int done = 0;
2374 struct pagevec pvec;
2375 int nr_pages;
2376 pgoff_t index;
2377 pgoff_t end; /* Inclusive */
2378 int scanned = 0;
2379 int range_whole = 0;
2380
2381 if (wbc->nonblocking && bdi_write_congested(bdi)) {
2382 wbc->encountered_congestion = 1;
2383 return 0;
2384 }
2385
2386 pagevec_init(&pvec, 0);
2387 if (wbc->range_cyclic) {
2388 index = mapping->writeback_index; /* Start from prev offset */
2389 end = -1;
2390 } else {
2391 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2392 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2393 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2394 range_whole = 1;
2395 scanned = 1;
2396 }
2397retry:
2398 while (!done && (index <= end) &&
2399 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
2400 PAGECACHE_TAG_DIRTY, min(end - index,
2401 (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2402 unsigned i;
2403
2404 scanned = 1;
2405 for (i = 0; i < nr_pages; i++) {
2406 struct page *page = pvec.pages[i];
2407
2408 /*
2409 * At this point we hold neither mapping->tree_lock nor
2410 * lock on the page itself: the page may be truncated or
2411 * invalidated (changing page->mapping to NULL), or even
2412 * swizzled back from swapper_space to tmpfs file
2413 * mapping
2414 */
2415 if (tree->ops && tree->ops->write_cache_pages_lock_hook)
2416 tree->ops->write_cache_pages_lock_hook(page);
2417 else
2418 lock_page(page);
2419
2420 if (unlikely(page->mapping != mapping)) {
2421 unlock_page(page);
2422 continue;
2423 }
2424
2425 if (!wbc->range_cyclic && page->index > end) {
2426 done = 1;
2427 unlock_page(page);
2428 continue;
2429 }
2430
2431 if (wbc->sync_mode != WB_SYNC_NONE) {
2432 if (PageWriteback(page))
2433 flush_fn(data);
2434 wait_on_page_writeback(page);
2435 }
2436
2437 if (PageWriteback(page) ||
2438 !clear_page_dirty_for_io(page)) {
2439 unlock_page(page);
2440 continue;
2441 }
2442
2443 ret = (*writepage)(page, wbc, data);
2444
2445 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
2446 unlock_page(page);
2447 ret = 0;
2448 }
2449 if (ret || wbc->nr_to_write <= 0)
2450 done = 1;
2451 if (wbc->nonblocking && bdi_write_congested(bdi)) {
2452 wbc->encountered_congestion = 1;
2453 done = 1;
2454 }
2455 }
2456 pagevec_release(&pvec);
2457 cond_resched();
2458 }
2459 if (!scanned && !done) {
2460 /*
2461 * We hit the last page and there is more work to be done: wrap
2462 * back to the start of the file
2463 */
2464 scanned = 1;
2465 index = 0;
2466 goto retry;
2467 }
2468 return ret;
2469}
2470
2471static noinline void flush_write_bio(void *data)
2472{
2473 struct extent_page_data *epd = data;
2474 if (epd->bio) {
2475 submit_one_bio(WRITE, epd->bio, 0, 0);
2476 epd->bio = NULL;
2477 }
2478}
2479
2480int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
2481 get_extent_t *get_extent,
2482 struct writeback_control *wbc)
2483{
2484 int ret;
2485 struct address_space *mapping = page->mapping;
2486 struct extent_page_data epd = {
2487 .bio = NULL,
2488 .tree = tree,
2489 .get_extent = get_extent,
2490 .extent_locked = 0,
2491 };
2492 struct writeback_control wbc_writepages = {
2493 .bdi = wbc->bdi,
2494 .sync_mode = WB_SYNC_NONE,
2495 .older_than_this = NULL,
2496 .nr_to_write = 64,
2497 .range_start = page_offset(page) + PAGE_CACHE_SIZE,
2498 .range_end = (loff_t)-1,
2499 };
2500
2501
2502 ret = __extent_writepage(page, wbc, &epd);
2503
2504 extent_write_cache_pages(tree, mapping, &wbc_writepages,
2505 __extent_writepage, &epd, flush_write_bio);
2506 if (epd.bio)
2507 submit_one_bio(WRITE, epd.bio, 0, 0);
2508 return ret;
2509}
2510
2511int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
2512 u64 start, u64 end, get_extent_t *get_extent,
2513 int mode)
2514{
2515 int ret = 0;
2516 struct address_space *mapping = inode->i_mapping;
2517 struct page *page;
2518 unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
2519 PAGE_CACHE_SHIFT;
2520
2521 struct extent_page_data epd = {
2522 .bio = NULL,
2523 .tree = tree,
2524 .get_extent = get_extent,
2525 .extent_locked = 1,
2526 };
2527 struct writeback_control wbc_writepages = {
2528 .bdi = inode->i_mapping->backing_dev_info,
2529 .sync_mode = mode,
2530 .older_than_this = NULL,
2531 .nr_to_write = nr_pages * 2,
2532 .range_start = start,
2533 .range_end = end + 1,
2534 };
2535
2536 while (start <= end) {
2537 page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
2538 if (clear_page_dirty_for_io(page))
2539 ret = __extent_writepage(page, &wbc_writepages, &epd);
2540 else {
2541 if (tree->ops && tree->ops->writepage_end_io_hook)
2542 tree->ops->writepage_end_io_hook(page, start,
2543 start + PAGE_CACHE_SIZE - 1,
2544 NULL, 1);
2545 unlock_page(page);
2546 }
2547 page_cache_release(page);
2548 start += PAGE_CACHE_SIZE;
2549 }
2550
2551 if (epd.bio)
2552 submit_one_bio(WRITE, epd.bio, 0, 0);
2553 return ret;
2554}
2555
2556int extent_writepages(struct extent_io_tree *tree,
2557 struct address_space *mapping,
2558 get_extent_t *get_extent,
2559 struct writeback_control *wbc)
2560{
2561 int ret = 0;
2562 struct extent_page_data epd = {
2563 .bio = NULL,
2564 .tree = tree,
2565 .get_extent = get_extent,
2566 .extent_locked = 0,
2567 };
2568
2569 ret = extent_write_cache_pages(tree, mapping, wbc,
2570 __extent_writepage, &epd,
2571 flush_write_bio);
2572 if (epd.bio)
2573 submit_one_bio(WRITE, epd.bio, 0, 0);
2574 return ret;
2575}
2576
2577int extent_readpages(struct extent_io_tree *tree,
2578 struct address_space *mapping,
2579 struct list_head *pages, unsigned nr_pages,
2580 get_extent_t get_extent)
2581{
2582 struct bio *bio = NULL;
2583 unsigned page_idx;
2584 struct pagevec pvec;
2585 unsigned long bio_flags = 0;
2586
2587 pagevec_init(&pvec, 0);
2588 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
2589 struct page *page = list_entry(pages->prev, struct page, lru);
2590
2591 prefetchw(&page->flags);
2592 list_del(&page->lru);
2593 /*
2594 * what we want to do here is call add_to_page_cache_lru,
2595 * but that isn't exported, so we reproduce it here
2596 */
2597 if (!add_to_page_cache(page, mapping,
2598 page->index, GFP_KERNEL)) {
2599
2600 /* open coding of lru_cache_add, also not exported */
2601 page_cache_get(page);
2602 if (!pagevec_add(&pvec, page))
2603 __pagevec_lru_add_file(&pvec);
2604 __extent_read_full_page(tree, page, get_extent,
2605 &bio, 0, &bio_flags);
2606 }
2607 page_cache_release(page);
2608 }
2609 if (pagevec_count(&pvec))
2610 __pagevec_lru_add_file(&pvec);
2611 BUG_ON(!list_empty(pages));
2612 if (bio)
2613 submit_one_bio(READ, bio, 0, bio_flags);
2614 return 0;
2615}
2616
2617/*
2618 * basic invalidatepage code, this waits on any locked or writeback
2619 * ranges corresponding to the page, and then deletes any extent state
2620 * records from the tree
2621 */
2622int extent_invalidatepage(struct extent_io_tree *tree,
2623 struct page *page, unsigned long offset)
2624{
2625 u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
2626 u64 end = start + PAGE_CACHE_SIZE - 1;
2627 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
2628
2629 start += (offset + blocksize - 1) & ~(blocksize - 1);
2630 if (start > end)
2631 return 0;
2632
2633 lock_extent(tree, start, end, GFP_NOFS);
2634 wait_on_extent_writeback(tree, start, end);
2635 clear_extent_bit(tree, start, end,
2636 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC,
2637 1, 1, GFP_NOFS);
2638 return 0;
2639}
2640
2641/*
2642 * simple commit_write call, set_range_dirty is used to mark both
2643 * the pages and the extent records as dirty
2644 */
2645int extent_commit_write(struct extent_io_tree *tree,
2646 struct inode *inode, struct page *page,
2647 unsigned from, unsigned to)
2648{
2649 loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
2650
2651 set_page_extent_mapped(page);
2652 set_page_dirty(page);
2653
2654 if (pos > inode->i_size) {
2655 i_size_write(inode, pos);
2656 mark_inode_dirty(inode);
2657 }
2658 return 0;
2659}
2660
2661int extent_prepare_write(struct extent_io_tree *tree,
2662 struct inode *inode, struct page *page,
2663 unsigned from, unsigned to, get_extent_t *get_extent)
2664{
2665 u64 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2666 u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
2667 u64 block_start;
2668 u64 orig_block_start;
2669 u64 block_end;
2670 u64 cur_end;
2671 struct extent_map *em;
2672 unsigned blocksize = 1 << inode->i_blkbits;
2673 size_t page_offset = 0;
2674 size_t block_off_start;
2675 size_t block_off_end;
2676 int err = 0;
2677 int iocount = 0;
2678 int ret = 0;
2679 int isnew;
2680
2681 set_page_extent_mapped(page);
2682
2683 block_start = (page_start + from) & ~((u64)blocksize - 1);
2684 block_end = (page_start + to - 1) | (blocksize - 1);
2685 orig_block_start = block_start;
2686
2687 lock_extent(tree, page_start, page_end, GFP_NOFS);
2688 while (block_start <= block_end) {
2689 em = get_extent(inode, page, page_offset, block_start,
2690 block_end - block_start + 1, 1);
2691 if (IS_ERR(em) || !em)
2692 goto err;
2693
2694 cur_end = min(block_end, extent_map_end(em) - 1);
2695 block_off_start = block_start & (PAGE_CACHE_SIZE - 1);
2696 block_off_end = block_off_start + blocksize;
2697 isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS);
2698
2699 if (!PageUptodate(page) && isnew &&
2700 (block_off_end > to || block_off_start < from)) {
2701 void *kaddr;
2702
2703 kaddr = kmap_atomic(page, KM_USER0);
2704 if (block_off_end > to)
2705 memset(kaddr + to, 0, block_off_end - to);
2706 if (block_off_start < from)
2707 memset(kaddr + block_off_start, 0,
2708 from - block_off_start);
2709 flush_dcache_page(page);
2710 kunmap_atomic(kaddr, KM_USER0);
2711 }
2712 if ((em->block_start != EXTENT_MAP_HOLE &&
2713 em->block_start != EXTENT_MAP_INLINE) &&
2714 !isnew && !PageUptodate(page) &&
2715 (block_off_end > to || block_off_start < from) &&
2716 !test_range_bit(tree, block_start, cur_end,
2717 EXTENT_UPTODATE, 1)) {
2718 u64 sector;
2719 u64 extent_offset = block_start - em->start;
2720 size_t iosize;
2721 sector = (em->block_start + extent_offset) >> 9;
2722 iosize = (cur_end - block_start + blocksize) &
2723 ~((u64)blocksize - 1);
2724 /*
2725 * we've already got the extent locked, but we
2726 * need to split the state such that our end_bio
2727 * handler can clear the lock.
2728 */
2729 set_extent_bit(tree, block_start,
2730 block_start + iosize - 1,
2731 EXTENT_LOCKED, 0, NULL, GFP_NOFS);
2732 ret = submit_extent_page(READ, tree, page,
2733 sector, iosize, page_offset, em->bdev,
2734 NULL, 1,
2735 end_bio_extent_preparewrite, 0,
2736 0, 0);
2737 iocount++;
2738 block_start = block_start + iosize;
2739 } else {
2740 set_extent_uptodate(tree, block_start, cur_end,
2741 GFP_NOFS);
2742 unlock_extent(tree, block_start, cur_end, GFP_NOFS);
2743 block_start = cur_end + 1;
2744 }
2745 page_offset = block_start & (PAGE_CACHE_SIZE - 1);
2746 free_extent_map(em);
2747 }
2748 if (iocount) {
2749 wait_extent_bit(tree, orig_block_start,
2750 block_end, EXTENT_LOCKED);
2751 }
2752 check_page_uptodate(tree, page);
2753err:
2754 /* FIXME, zero out newly allocated blocks on error */
2755 return err;
2756}
2757
2758/*
2759 * a helper for releasepage, this tests for areas of the page that
2760 * are locked or under IO and drops the related state bits if it is safe
2761 * to drop the page.
2762 */
2763int try_release_extent_state(struct extent_map_tree *map,
2764 struct extent_io_tree *tree, struct page *page,
2765 gfp_t mask)
2766{
2767 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2768 u64 end = start + PAGE_CACHE_SIZE - 1;
2769 int ret = 1;
2770
2771 if (test_range_bit(tree, start, end,
2772 EXTENT_IOBITS | EXTENT_ORDERED, 0))
2773 ret = 0;
2774 else {
2775 if ((mask & GFP_NOFS) == GFP_NOFS)
2776 mask = GFP_NOFS;
2777 clear_extent_bit(tree, start, end, EXTENT_UPTODATE,
2778 1, 1, mask);
2779 }
2780 return ret;
2781}
2782
2783/*
2784 * a helper for releasepage. As long as there are no locked extents
2785 * in the range corresponding to the page, both state records and extent
2786 * map records are removed
2787 */
2788int try_release_extent_mapping(struct extent_map_tree *map,
2789 struct extent_io_tree *tree, struct page *page,
2790 gfp_t mask)
2791{
2792 struct extent_map *em;
2793 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2794 u64 end = start + PAGE_CACHE_SIZE - 1;
2795
2796 if ((mask & __GFP_WAIT) &&
2797 page->mapping->host->i_size > 16 * 1024 * 1024) {
2798 u64 len;
2799 while (start <= end) {
2800 len = end - start + 1;
2801 spin_lock(&map->lock);
2802 em = lookup_extent_mapping(map, start, len);
2803 if (!em || IS_ERR(em)) {
2804 spin_unlock(&map->lock);
2805 break;
2806 }
2807 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
2808 em->start != start) {
2809 spin_unlock(&map->lock);
2810 free_extent_map(em);
2811 break;
2812 }
2813 if (!test_range_bit(tree, em->start,
2814 extent_map_end(em) - 1,
2815 EXTENT_LOCKED | EXTENT_WRITEBACK |
2816 EXTENT_ORDERED,
2817 0)) {
2818 remove_extent_mapping(map, em);
2819 /* once for the rb tree */
2820 free_extent_map(em);
2821 }
2822 start = extent_map_end(em);
2823 spin_unlock(&map->lock);
2824
2825 /* once for us */
2826 free_extent_map(em);
2827 }
2828 }
2829 return try_release_extent_state(map, tree, page, mask);
2830}
2831
2832sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
2833 get_extent_t *get_extent)
2834{
2835 struct inode *inode = mapping->host;
2836 u64 start = iblock << inode->i_blkbits;
2837 sector_t sector = 0;
2838 size_t blksize = (1 << inode->i_blkbits);
2839 struct extent_map *em;
2840
2841 lock_extent(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
2842 GFP_NOFS);
2843 em = get_extent(inode, NULL, 0, start, blksize, 0);
2844 unlock_extent(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
2845 GFP_NOFS);
2846 if (!em || IS_ERR(em))
2847 return 0;
2848
2849 if (em->block_start > EXTENT_MAP_LAST_BYTE)
2850 goto out;
2851
2852 sector = (em->block_start + start - em->start) >> inode->i_blkbits;
2853out:
2854 free_extent_map(em);
2855 return sector;
2856}
2857
2858static inline struct page *extent_buffer_page(struct extent_buffer *eb,
2859 unsigned long i)
2860{
2861 struct page *p;
2862 struct address_space *mapping;
2863
2864 if (i == 0)
2865 return eb->first_page;
2866 i += eb->start >> PAGE_CACHE_SHIFT;
2867 mapping = eb->first_page->mapping;
2868 if (!mapping)
2869 return NULL;
2870
2871 /*
2872 * extent_buffer_page is only called after pinning the page
2873 * by increasing the reference count. So we know the page must
2874 * be in the radix tree.
2875 */
2876 rcu_read_lock();
2877 p = radix_tree_lookup(&mapping->page_tree, i);
2878 rcu_read_unlock();
2879
2880 return p;
2881}
2882
2883static inline unsigned long num_extent_pages(u64 start, u64 len)
2884{
2885 return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
2886 (start >> PAGE_CACHE_SHIFT);
2887}
2888
2889static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
2890 u64 start,
2891 unsigned long len,
2892 gfp_t mask)
2893{
2894 struct extent_buffer *eb = NULL;
2895#ifdef LEAK_DEBUG
2896 unsigned long flags;
2897#endif
2898
2899 eb = kmem_cache_zalloc(extent_buffer_cache, mask);
2900 eb->start = start;
2901 eb->len = len;
2902 mutex_init(&eb->mutex);
2903#ifdef LEAK_DEBUG
2904 spin_lock_irqsave(&leak_lock, flags);
2905 list_add(&eb->leak_list, &buffers);
2906 spin_unlock_irqrestore(&leak_lock, flags);
2907#endif
2908 atomic_set(&eb->refs, 1);
2909
2910 return eb;
2911}
2912
2913static void __free_extent_buffer(struct extent_buffer *eb)
2914{
2915#ifdef LEAK_DEBUG
2916 unsigned long flags;
2917 spin_lock_irqsave(&leak_lock, flags);
2918 list_del(&eb->leak_list);
2919 spin_unlock_irqrestore(&leak_lock, flags);
2920#endif
2921 kmem_cache_free(extent_buffer_cache, eb);
2922}
2923
2924struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
2925 u64 start, unsigned long len,
2926 struct page *page0,
2927 gfp_t mask)
2928{
2929 unsigned long num_pages = num_extent_pages(start, len);
2930 unsigned long i;
2931 unsigned long index = start >> PAGE_CACHE_SHIFT;
2932 struct extent_buffer *eb;
2933 struct extent_buffer *exists = NULL;
2934 struct page *p;
2935 struct address_space *mapping = tree->mapping;
2936 int uptodate = 1;
2937
2938 spin_lock(&tree->buffer_lock);
2939 eb = buffer_search(tree, start);
2940 if (eb) {
2941 atomic_inc(&eb->refs);
2942 spin_unlock(&tree->buffer_lock);
2943 mark_page_accessed(eb->first_page);
2944 return eb;
2945 }
2946 spin_unlock(&tree->buffer_lock);
2947
2948 eb = __alloc_extent_buffer(tree, start, len, mask);
2949 if (!eb)
2950 return NULL;
2951
2952 if (page0) {
2953 eb->first_page = page0;
2954 i = 1;
2955 index++;
2956 page_cache_get(page0);
2957 mark_page_accessed(page0);
2958 set_page_extent_mapped(page0);
2959 set_page_extent_head(page0, len);
2960 uptodate = PageUptodate(page0);
2961 } else {
2962 i = 0;
2963 }
2964 for (; i < num_pages; i++, index++) {
2965 p = find_or_create_page(mapping, index, mask | __GFP_HIGHMEM);
2966 if (!p) {
2967 WARN_ON(1);
2968 goto free_eb;
2969 }
2970 set_page_extent_mapped(p);
2971 mark_page_accessed(p);
2972 if (i == 0) {
2973 eb->first_page = p;
2974 set_page_extent_head(p, len);
2975 } else {
2976 set_page_private(p, EXTENT_PAGE_PRIVATE);
2977 }
2978 if (!PageUptodate(p))
2979 uptodate = 0;
2980 unlock_page(p);
2981 }
2982 if (uptodate)
2983 eb->flags |= EXTENT_UPTODATE;
2984 eb->flags |= EXTENT_BUFFER_FILLED;
2985
2986 spin_lock(&tree->buffer_lock);
2987 exists = buffer_tree_insert(tree, start, &eb->rb_node);
2988 if (exists) {
2989 /* add one reference for the caller */
2990 atomic_inc(&exists->refs);
2991 spin_unlock(&tree->buffer_lock);
2992 goto free_eb;
2993 }
2994 spin_unlock(&tree->buffer_lock);
2995
2996 /* add one reference for the tree */
2997 atomic_inc(&eb->refs);
2998 return eb;
2999
3000free_eb:
3001 if (!atomic_dec_and_test(&eb->refs))
3002 return exists;
3003 for (index = 1; index < i; index++)
3004 page_cache_release(extent_buffer_page(eb, index));
3005 page_cache_release(extent_buffer_page(eb, 0));
3006 __free_extent_buffer(eb);
3007 return exists;
3008}
3009
3010struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
3011 u64 start, unsigned long len,
3012 gfp_t mask)
3013{
3014 struct extent_buffer *eb;
3015
3016 spin_lock(&tree->buffer_lock);
3017 eb = buffer_search(tree, start);
3018 if (eb)
3019 atomic_inc(&eb->refs);
3020 spin_unlock(&tree->buffer_lock);
3021
3022 if (eb)
3023 mark_page_accessed(eb->first_page);
3024
3025 return eb;
3026}
3027
3028void free_extent_buffer(struct extent_buffer *eb)
3029{
3030 if (!eb)
3031 return;
3032
3033 if (!atomic_dec_and_test(&eb->refs))
3034 return;
3035
3036 WARN_ON(1);
3037}
3038
3039int clear_extent_buffer_dirty(struct extent_io_tree *tree,
3040 struct extent_buffer *eb)
3041{
3042 int set;
3043 unsigned long i;
3044 unsigned long num_pages;
3045 struct page *page;
3046
3047 u64 start = eb->start;
3048 u64 end = start + eb->len - 1;
3049
3050 set = clear_extent_dirty(tree, start, end, GFP_NOFS);
3051 num_pages = num_extent_pages(eb->start, eb->len);
3052
3053 for (i = 0; i < num_pages; i++) {
3054 page = extent_buffer_page(eb, i);
3055 if (!set && !PageDirty(page))
3056 continue;
3057
3058 lock_page(page);
3059 if (i == 0)
3060 set_page_extent_head(page, eb->len);
3061 else
3062 set_page_private(page, EXTENT_PAGE_PRIVATE);
3063
3064 /*
3065 * if we're on the last page or the first page and the
3066 * block isn't aligned on a page boundary, do extra checks
3067 * to make sure we don't clean page that is partially dirty
3068 */
3069 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3070 ((i == num_pages - 1) &&
3071 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3072 start = (u64)page->index << PAGE_CACHE_SHIFT;
3073 end = start + PAGE_CACHE_SIZE - 1;
3074 if (test_range_bit(tree, start, end,
3075 EXTENT_DIRTY, 0)) {
3076 unlock_page(page);
3077 continue;
3078 }
3079 }
3080 clear_page_dirty_for_io(page);
3081 spin_lock_irq(&page->mapping->tree_lock);
3082 if (!PageDirty(page)) {
3083 radix_tree_tag_clear(&page->mapping->page_tree,
3084 page_index(page),
3085 PAGECACHE_TAG_DIRTY);
3086 }
3087 spin_unlock_irq(&page->mapping->tree_lock);
3088 unlock_page(page);
3089 }
3090 return 0;
3091}
3092
3093int wait_on_extent_buffer_writeback(struct extent_io_tree *tree,
3094 struct extent_buffer *eb)
3095{
3096 return wait_on_extent_writeback(tree, eb->start,
3097 eb->start + eb->len - 1);
3098}
3099
3100int set_extent_buffer_dirty(struct extent_io_tree *tree,
3101 struct extent_buffer *eb)
3102{
3103 unsigned long i;
3104 unsigned long num_pages;
3105
3106 num_pages = num_extent_pages(eb->start, eb->len);
3107 for (i = 0; i < num_pages; i++) {
3108 struct page *page = extent_buffer_page(eb, i);
3109 /* writepage may need to do something special for the
3110 * first page, we have to make sure page->private is
3111 * properly set. releasepage may drop page->private
3112 * on us if the page isn't already dirty.
3113 */
3114 lock_page(page);
3115 if (i == 0) {
3116 set_page_extent_head(page, eb->len);
3117 } else if (PagePrivate(page) &&
3118 page->private != EXTENT_PAGE_PRIVATE) {
3119 set_page_extent_mapped(page);
3120 }
3121 __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3122 set_extent_dirty(tree, page_offset(page),
3123 page_offset(page) + PAGE_CACHE_SIZE - 1,
3124 GFP_NOFS);
3125 unlock_page(page);
3126 }
3127 return 0;
3128}
3129
3130int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3131 struct extent_buffer *eb)
3132{
3133 unsigned long i;
3134 struct page *page;
3135 unsigned long num_pages;
3136
3137 num_pages = num_extent_pages(eb->start, eb->len);
3138 eb->flags &= ~EXTENT_UPTODATE;
3139
3140 clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3141 GFP_NOFS);
3142 for (i = 0; i < num_pages; i++) {
3143 page = extent_buffer_page(eb, i);
3144 if (page)
3145 ClearPageUptodate(page);
3146 }
3147 return 0;
3148}
3149
3150int set_extent_buffer_uptodate(struct extent_io_tree *tree,
3151 struct extent_buffer *eb)
3152{
3153 unsigned long i;
3154 struct page *page;
3155 unsigned long num_pages;
3156
3157 num_pages = num_extent_pages(eb->start, eb->len);
3158
3159 set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3160 GFP_NOFS);
3161 for (i = 0; i < num_pages; i++) {
3162 page = extent_buffer_page(eb, i);
3163 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3164 ((i == num_pages - 1) &&
3165 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3166 check_page_uptodate(tree, page);
3167 continue;
3168 }
3169 SetPageUptodate(page);
3170 }
3171 return 0;
3172}
3173
3174int extent_range_uptodate(struct extent_io_tree *tree,
3175 u64 start, u64 end)
3176{
3177 struct page *page;
3178 int ret;
3179 int pg_uptodate = 1;
3180 int uptodate;
3181 unsigned long index;
3182
3183 ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1);
3184 if (ret)
3185 return 1;
3186 while (start <= end) {
3187 index = start >> PAGE_CACHE_SHIFT;
3188 page = find_get_page(tree->mapping, index);
3189 uptodate = PageUptodate(page);
3190 page_cache_release(page);
3191 if (!uptodate) {
3192 pg_uptodate = 0;
3193 break;
3194 }
3195 start += PAGE_CACHE_SIZE;
3196 }
3197 return pg_uptodate;
3198}
3199
3200int extent_buffer_uptodate(struct extent_io_tree *tree,
3201 struct extent_buffer *eb)
3202{
3203 int ret = 0;
3204 unsigned long num_pages;
3205 unsigned long i;
3206 struct page *page;
3207 int pg_uptodate = 1;
3208
3209 if (eb->flags & EXTENT_UPTODATE)
3210 return 1;
3211
3212 ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3213 EXTENT_UPTODATE, 1);
3214 if (ret)
3215 return ret;
3216
3217 num_pages = num_extent_pages(eb->start, eb->len);
3218 for (i = 0; i < num_pages; i++) {
3219 page = extent_buffer_page(eb, i);
3220 if (!PageUptodate(page)) {
3221 pg_uptodate = 0;
3222 break;
3223 }
3224 }
3225 return pg_uptodate;
3226}
3227
3228int read_extent_buffer_pages(struct extent_io_tree *tree,
3229 struct extent_buffer *eb,
3230 u64 start, int wait,
3231 get_extent_t *get_extent, int mirror_num)
3232{
3233 unsigned long i;
3234 unsigned long start_i;
3235 struct page *page;
3236 int err;
3237 int ret = 0;
3238 int locked_pages = 0;
3239 int all_uptodate = 1;
3240 int inc_all_pages = 0;
3241 unsigned long num_pages;
3242 struct bio *bio = NULL;
3243 unsigned long bio_flags = 0;
3244
3245 if (eb->flags & EXTENT_UPTODATE)
3246 return 0;
3247
3248 if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3249 EXTENT_UPTODATE, 1)) {
3250 return 0;
3251 }
3252
3253 if (start) {
3254 WARN_ON(start < eb->start);
3255 start_i = (start >> PAGE_CACHE_SHIFT) -
3256 (eb->start >> PAGE_CACHE_SHIFT);
3257 } else {
3258 start_i = 0;
3259 }
3260
3261 num_pages = num_extent_pages(eb->start, eb->len);
3262 for (i = start_i; i < num_pages; i++) {
3263 page = extent_buffer_page(eb, i);
3264 if (!wait) {
3265 if (!trylock_page(page))
3266 goto unlock_exit;
3267 } else {
3268 lock_page(page);
3269 }
3270 locked_pages++;
3271 if (!PageUptodate(page))
3272 all_uptodate = 0;
3273 }
3274 if (all_uptodate) {
3275 if (start_i == 0)
3276 eb->flags |= EXTENT_UPTODATE;
3277 goto unlock_exit;
3278 }
3279
3280 for (i = start_i; i < num_pages; i++) {
3281 page = extent_buffer_page(eb, i);
3282 if (inc_all_pages)
3283 page_cache_get(page);
3284 if (!PageUptodate(page)) {
3285 if (start_i == 0)
3286 inc_all_pages = 1;
3287 ClearPageError(page);
3288 err = __extent_read_full_page(tree, page,
3289 get_extent, &bio,
3290 mirror_num, &bio_flags);
3291 if (err)
3292 ret = err;
3293 } else {
3294 unlock_page(page);
3295 }
3296 }
3297
3298 if (bio)
3299 submit_one_bio(READ, bio, mirror_num, bio_flags);
3300
3301 if (ret || !wait)
3302 return ret;
3303
3304 for (i = start_i; i < num_pages; i++) {
3305 page = extent_buffer_page(eb, i);
3306 wait_on_page_locked(page);
3307 if (!PageUptodate(page))
3308 ret = -EIO;
3309 }
3310
3311 if (!ret)
3312 eb->flags |= EXTENT_UPTODATE;
3313 return ret;
3314
3315unlock_exit:
3316 i = start_i;
3317 while (locked_pages > 0) {
3318 page = extent_buffer_page(eb, i);
3319 i++;
3320 unlock_page(page);
3321 locked_pages--;
3322 }
3323 return ret;
3324}
3325
3326void read_extent_buffer(struct extent_buffer *eb, void *dstv,
3327 unsigned long start,
3328 unsigned long len)
3329{
3330 size_t cur;
3331 size_t offset;
3332 struct page *page;
3333 char *kaddr;
3334 char *dst = (char *)dstv;
3335 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3336 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3337
3338 WARN_ON(start > eb->len);
3339 WARN_ON(start + len > eb->start + eb->len);
3340
3341 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3342
3343 while (len > 0) {
3344 page = extent_buffer_page(eb, i);
3345
3346 cur = min(len, (PAGE_CACHE_SIZE - offset));
3347 kaddr = kmap_atomic(page, KM_USER1);
3348 memcpy(dst, kaddr + offset, cur);
3349 kunmap_atomic(kaddr, KM_USER1);
3350
3351 dst += cur;
3352 len -= cur;
3353 offset = 0;
3354 i++;
3355 }
3356}
3357
3358int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
3359 unsigned long min_len, char **token, char **map,
3360 unsigned long *map_start,
3361 unsigned long *map_len, int km)
3362{
3363 size_t offset = start & (PAGE_CACHE_SIZE - 1);
3364 char *kaddr;
3365 struct page *p;
3366 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3367 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3368 unsigned long end_i = (start_offset + start + min_len - 1) >>
3369 PAGE_CACHE_SHIFT;
3370
3371 if (i != end_i)
3372 return -EINVAL;
3373
3374 if (i == 0) {
3375 offset = start_offset;
3376 *map_start = 0;
3377 } else {
3378 offset = 0;
3379 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
3380 }
3381
3382 if (start + min_len > eb->len) {
3383 printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
3384 "wanted %lu %lu\n", (unsigned long long)eb->start,
3385 eb->len, start, min_len);
3386 WARN_ON(1);
3387 }
3388
3389 p = extent_buffer_page(eb, i);
3390 kaddr = kmap_atomic(p, km);
3391 *token = kaddr;
3392 *map = kaddr + offset;
3393 *map_len = PAGE_CACHE_SIZE - offset;
3394 return 0;
3395}
3396
3397int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
3398 unsigned long min_len,
3399 char **token, char **map,
3400 unsigned long *map_start,
3401 unsigned long *map_len, int km)
3402{
3403 int err;
3404 int save = 0;
3405 if (eb->map_token) {
3406 unmap_extent_buffer(eb, eb->map_token, km);
3407 eb->map_token = NULL;
3408 save = 1;
3409 WARN_ON(!mutex_is_locked(&eb->mutex));
3410 }
3411 err = map_private_extent_buffer(eb, start, min_len, token, map,
3412 map_start, map_len, km);
3413 if (!err && save) {
3414 eb->map_token = *token;
3415 eb->kaddr = *map;
3416 eb->map_start = *map_start;
3417 eb->map_len = *map_len;
3418 }
3419 return err;
3420}
3421
3422void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km)
3423{
3424 kunmap_atomic(token, km);
3425}
3426
3427int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
3428 unsigned long start,
3429 unsigned long len)
3430{
3431 size_t cur;
3432 size_t offset;
3433 struct page *page;
3434 char *kaddr;
3435 char *ptr = (char *)ptrv;
3436 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3437 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3438 int ret = 0;
3439
3440 WARN_ON(start > eb->len);
3441 WARN_ON(start + len > eb->start + eb->len);
3442
3443 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3444
3445 while (len > 0) {
3446 page = extent_buffer_page(eb, i);
3447
3448 cur = min(len, (PAGE_CACHE_SIZE - offset));
3449
3450 kaddr = kmap_atomic(page, KM_USER0);
3451 ret = memcmp(ptr, kaddr + offset, cur);
3452 kunmap_atomic(kaddr, KM_USER0);
3453 if (ret)
3454 break;
3455
3456 ptr += cur;
3457 len -= cur;
3458 offset = 0;
3459 i++;
3460 }
3461 return ret;
3462}
3463
3464void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
3465 unsigned long start, unsigned long len)
3466{
3467 size_t cur;
3468 size_t offset;
3469 struct page *page;
3470 char *kaddr;
3471 char *src = (char *)srcv;
3472 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3473 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3474
3475 WARN_ON(start > eb->len);
3476 WARN_ON(start + len > eb->start + eb->len);
3477
3478 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3479
3480 while (len > 0) {
3481 page = extent_buffer_page(eb, i);
3482 WARN_ON(!PageUptodate(page));
3483
3484 cur = min(len, PAGE_CACHE_SIZE - offset);
3485 kaddr = kmap_atomic(page, KM_USER1);
3486 memcpy(kaddr + offset, src, cur);
3487 kunmap_atomic(kaddr, KM_USER1);
3488
3489 src += cur;
3490 len -= cur;
3491 offset = 0;
3492 i++;
3493 }
3494}
3495
3496void memset_extent_buffer(struct extent_buffer *eb, char c,
3497 unsigned long start, unsigned long len)
3498{
3499 size_t cur;
3500 size_t offset;
3501 struct page *page;
3502 char *kaddr;
3503 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3504 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3505
3506 WARN_ON(start > eb->len);
3507 WARN_ON(start + len > eb->start + eb->len);
3508
3509 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3510
3511 while (len > 0) {
3512 page = extent_buffer_page(eb, i);
3513 WARN_ON(!PageUptodate(page));
3514
3515 cur = min(len, PAGE_CACHE_SIZE - offset);
3516 kaddr = kmap_atomic(page, KM_USER0);
3517 memset(kaddr + offset, c, cur);
3518 kunmap_atomic(kaddr, KM_USER0);
3519
3520 len -= cur;
3521 offset = 0;
3522 i++;
3523 }
3524}
3525
3526void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
3527 unsigned long dst_offset, unsigned long src_offset,
3528 unsigned long len)
3529{
3530 u64 dst_len = dst->len;
3531 size_t cur;
3532 size_t offset;
3533 struct page *page;
3534 char *kaddr;
3535 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3536 unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3537
3538 WARN_ON(src->len != dst_len);
3539
3540 offset = (start_offset + dst_offset) &
3541 ((unsigned long)PAGE_CACHE_SIZE - 1);
3542
3543 while (len > 0) {
3544 page = extent_buffer_page(dst, i);
3545 WARN_ON(!PageUptodate(page));
3546
3547 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
3548
3549 kaddr = kmap_atomic(page, KM_USER0);
3550 read_extent_buffer(src, kaddr + offset, src_offset, cur);
3551 kunmap_atomic(kaddr, KM_USER0);
3552
3553 src_offset += cur;
3554 len -= cur;
3555 offset = 0;
3556 i++;
3557 }
3558}
3559
3560static void move_pages(struct page *dst_page, struct page *src_page,
3561 unsigned long dst_off, unsigned long src_off,
3562 unsigned long len)
3563{
3564 char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
3565 if (dst_page == src_page) {
3566 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
3567 } else {
3568 char *src_kaddr = kmap_atomic(src_page, KM_USER1);
3569 char *p = dst_kaddr + dst_off + len;
3570 char *s = src_kaddr + src_off + len;
3571
3572 while (len--)
3573 *--p = *--s;
3574
3575 kunmap_atomic(src_kaddr, KM_USER1);
3576 }
3577 kunmap_atomic(dst_kaddr, KM_USER0);
3578}
3579
3580static void copy_pages(struct page *dst_page, struct page *src_page,
3581 unsigned long dst_off, unsigned long src_off,
3582 unsigned long len)
3583{
3584 char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
3585 char *src_kaddr;
3586
3587 if (dst_page != src_page)
3588 src_kaddr = kmap_atomic(src_page, KM_USER1);
3589 else
3590 src_kaddr = dst_kaddr;
3591
3592 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
3593 kunmap_atomic(dst_kaddr, KM_USER0);
3594 if (dst_page != src_page)
3595 kunmap_atomic(src_kaddr, KM_USER1);
3596}
3597
3598void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3599 unsigned long src_offset, unsigned long len)
3600{
3601 size_t cur;
3602 size_t dst_off_in_page;
3603 size_t src_off_in_page;
3604 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3605 unsigned long dst_i;
3606 unsigned long src_i;
3607
3608 if (src_offset + len > dst->len) {
3609 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3610 "len %lu dst len %lu\n", src_offset, len, dst->len);
3611 BUG_ON(1);
3612 }
3613 if (dst_offset + len > dst->len) {
3614 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3615 "len %lu dst len %lu\n", dst_offset, len, dst->len);
3616 BUG_ON(1);
3617 }
3618
3619 while (len > 0) {
3620 dst_off_in_page = (start_offset + dst_offset) &
3621 ((unsigned long)PAGE_CACHE_SIZE - 1);
3622 src_off_in_page = (start_offset + src_offset) &
3623 ((unsigned long)PAGE_CACHE_SIZE - 1);
3624
3625 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3626 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
3627
3628 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
3629 src_off_in_page));
3630 cur = min_t(unsigned long, cur,
3631 (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
3632
3633 copy_pages(extent_buffer_page(dst, dst_i),
3634 extent_buffer_page(dst, src_i),
3635 dst_off_in_page, src_off_in_page, cur);
3636
3637 src_offset += cur;
3638 dst_offset += cur;
3639 len -= cur;
3640 }
3641}
3642
3643void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3644 unsigned long src_offset, unsigned long len)
3645{
3646 size_t cur;
3647 size_t dst_off_in_page;
3648 size_t src_off_in_page;
3649 unsigned long dst_end = dst_offset + len - 1;
3650 unsigned long src_end = src_offset + len - 1;
3651 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3652 unsigned long dst_i;
3653 unsigned long src_i;
3654
3655 if (src_offset + len > dst->len) {
3656 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3657 "len %lu len %lu\n", src_offset, len, dst->len);
3658 BUG_ON(1);
3659 }
3660 if (dst_offset + len > dst->len) {
3661 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3662 "len %lu len %lu\n", dst_offset, len, dst->len);
3663 BUG_ON(1);
3664 }
3665 if (dst_offset < src_offset) {
3666 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
3667 return;
3668 }
3669 while (len > 0) {
3670 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
3671 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
3672
3673 dst_off_in_page = (start_offset + dst_end) &
3674 ((unsigned long)PAGE_CACHE_SIZE - 1);
3675 src_off_in_page = (start_offset + src_end) &
3676 ((unsigned long)PAGE_CACHE_SIZE - 1);
3677
3678 cur = min_t(unsigned long, len, src_off_in_page + 1);
3679 cur = min(cur, dst_off_in_page + 1);
3680 move_pages(extent_buffer_page(dst, dst_i),
3681 extent_buffer_page(dst, src_i),
3682 dst_off_in_page - cur + 1,
3683 src_off_in_page - cur + 1, cur);
3684
3685 dst_end -= cur;
3686 src_end -= cur;
3687 len -= cur;
3688 }
3689}
3690
3691int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
3692{
3693 u64 start = page_offset(page);
3694 struct extent_buffer *eb;
3695 int ret = 1;
3696 unsigned long i;
3697 unsigned long num_pages;
3698
3699 spin_lock(&tree->buffer_lock);
3700 eb = buffer_search(tree, start);
3701 if (!eb)
3702 goto out;
3703
3704 if (atomic_read(&eb->refs) > 1) {
3705 ret = 0;
3706 goto out;
3707 }
3708 /* at this point we can safely release the extent buffer */
3709 num_pages = num_extent_pages(eb->start, eb->len);
3710 for (i = 0; i < num_pages; i++)
3711 page_cache_release(extent_buffer_page(eb, i));
3712 rb_erase(&eb->rb_node, &tree->buffer);
3713 __free_extent_buffer(eb);
3714out:
3715 spin_unlock(&tree->buffer_lock);
3716 return ret;
3717}
generated by cgit v1.2.2 (git 2.25.0) at 2025-12-11 18:34:04 -0500