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Btrfs: clean up for insert_state()
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / btrfs / extent_io.c
blob0d69425d0197b9d164e42b43f5959e33a5dd82fa
1 #include <linux/bitops.h>
2 #include <linux/slab.h>
3 #include <linux/bio.h>
4 #include <linux/mm.h>
5 #include <linux/pagemap.h>
6 #include <linux/page-flags.h>
7 #include <linux/module.h>
8 #include <linux/spinlock.h>
9 #include <linux/blkdev.h>
10 #include <linux/swap.h>
11 #include <linux/writeback.h>
12 #include <linux/pagevec.h>
13 #include <linux/prefetch.h>
14 #include <linux/cleancache.h>
15 #include "extent_io.h"
16 #include "extent_map.h"
17 #include "compat.h"
18 #include "ctree.h"
19 #include "btrfs_inode.h"
20
21 static struct kmem_cache *extent_state_cache;
22 static struct kmem_cache *extent_buffer_cache;
23
24 static LIST_HEAD(buffers);
25 static LIST_HEAD(states);
26
27 #define LEAK_DEBUG 0
28 #if LEAK_DEBUG
29 static DEFINE_SPINLOCK(leak_lock);
30 #endif
31
32 #define BUFFER_LRU_MAX 64
33
34 struct tree_entry {
35 u64 start;
36 u64 end;
37 struct rb_node rb_node;
38 };
39
40 struct extent_page_data {
41 struct bio *bio;
42 struct extent_io_tree *tree;
43 get_extent_t *get_extent;
44
45 /* tells writepage not to lock the state bits for this range
46 * it still does the unlocking
47 */
48 unsigned int extent_locked:1;
49
50 /* tells the submit_bio code to use a WRITE_SYNC */
51 unsigned int sync_io:1;
52 };
53
54 int __init extent_io_init(void)
55 {
56 extent_state_cache = kmem_cache_create("extent_state",
57 sizeof(struct extent_state), 0,
58 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
59 if (!extent_state_cache)
60 return -ENOMEM;
61
62 extent_buffer_cache = kmem_cache_create("extent_buffers",
63 sizeof(struct extent_buffer), 0,
64 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
65 if (!extent_buffer_cache)
66 goto free_state_cache;
67 return 0;
68
69 free_state_cache:
70 kmem_cache_destroy(extent_state_cache);
71 return -ENOMEM;
72 }
73
74 void extent_io_exit(void)
75 {
76 struct extent_state *state;
77 struct extent_buffer *eb;
78
79 while (!list_empty(&states)) {
80 state = list_entry(states.next, struct extent_state, leak_list);
81 printk(KERN_ERR "btrfs state leak: start %llu end %llu "
82 "state %lu in tree %p refs %d\n",
83 (unsigned long long)state->start,
84 (unsigned long long)state->end,
85 state->state, state->tree, atomic_read(&state->refs));
86 list_del(&state->leak_list);
87 kmem_cache_free(extent_state_cache, state);
88
89 }
90
91 while (!list_empty(&buffers)) {
92 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
93 printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
94 "refs %d\n", (unsigned long long)eb->start,
95 eb->len, atomic_read(&eb->refs));
96 list_del(&eb->leak_list);
97 kmem_cache_free(extent_buffer_cache, eb);
98 }
99 if (extent_state_cache)
100 kmem_cache_destroy(extent_state_cache);
101 if (extent_buffer_cache)
102 kmem_cache_destroy(extent_buffer_cache);
103 }
104
105 void extent_io_tree_init(struct extent_io_tree *tree,
106 struct address_space *mapping)
107 {
108 tree->state = RB_ROOT;
109 INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
110 tree->ops = NULL;
111 tree->dirty_bytes = 0;
112 spin_lock_init(&tree->lock);
113 spin_lock_init(&tree->buffer_lock);
114 tree->mapping = mapping;
115 }
116
117 static struct extent_state *alloc_extent_state(gfp_t mask)
118 {
119 struct extent_state *state;
120 #if LEAK_DEBUG
121 unsigned long flags;
122 #endif
123
124 state = kmem_cache_alloc(extent_state_cache, mask);
125 if (!state)
126 return state;
127 state->state = 0;
128 state->private = 0;
129 state->tree = NULL;
130 #if LEAK_DEBUG
131 spin_lock_irqsave(&leak_lock, flags);
132 list_add(&state->leak_list, &states);
133 spin_unlock_irqrestore(&leak_lock, flags);
134 #endif
135 atomic_set(&state->refs, 1);
136 init_waitqueue_head(&state->wq);
137 return state;
138 }
139
140 void free_extent_state(struct extent_state *state)
141 {
142 if (!state)
143 return;
144 if (atomic_dec_and_test(&state->refs)) {
145 #if LEAK_DEBUG
146 unsigned long flags;
147 #endif
148 WARN_ON(state->tree);
149 #if LEAK_DEBUG
150 spin_lock_irqsave(&leak_lock, flags);
151 list_del(&state->leak_list);
152 spin_unlock_irqrestore(&leak_lock, flags);
153 #endif
154 kmem_cache_free(extent_state_cache, state);
155 }
156 }
157
158 static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
159 struct rb_node *node)
160 {
161 struct rb_node **p = &root->rb_node;
162 struct rb_node *parent = NULL;
163 struct tree_entry *entry;
164
165 while (*p) {
166 parent = *p;
167 entry = rb_entry(parent, struct tree_entry, rb_node);
168
169 if (offset < entry->start)
170 p = &(*p)->rb_left;
171 else if (offset > entry->end)
172 p = &(*p)->rb_right;
173 else
174 return parent;
175 }
176
177 entry = rb_entry(node, struct tree_entry, rb_node);
178 rb_link_node(node, parent, p);
179 rb_insert_color(node, root);
180 return NULL;
181 }
182
183 static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
184 struct rb_node **prev_ret,
185 struct rb_node **next_ret)
186 {
187 struct rb_root *root = &tree->state;
188 struct rb_node *n = root->rb_node;
189 struct rb_node *prev = NULL;
190 struct rb_node *orig_prev = NULL;
191 struct tree_entry *entry;
192 struct tree_entry *prev_entry = NULL;
193
194 while (n) {
195 entry = rb_entry(n, struct tree_entry, rb_node);
196 prev = n;
197 prev_entry = entry;
198
199 if (offset < entry->start)
200 n = n->rb_left;
201 else if (offset > entry->end)
202 n = n->rb_right;
203 else
204 return n;
205 }
206
207 if (prev_ret) {
208 orig_prev = prev;
209 while (prev && offset > prev_entry->end) {
210 prev = rb_next(prev);
211 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
212 }
213 *prev_ret = prev;
214 prev = orig_prev;
215 }
216
217 if (next_ret) {
218 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
219 while (prev && offset < prev_entry->start) {
220 prev = rb_prev(prev);
221 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
222 }
223 *next_ret = prev;
224 }
225 return NULL;
226 }
227
228 static inline struct rb_node *tree_search(struct extent_io_tree *tree,
229 u64 offset)
230 {
231 struct rb_node *prev = NULL;
232 struct rb_node *ret;
233
234 ret = __etree_search(tree, offset, &prev, NULL);
235 if (!ret)
236 return prev;
237 return ret;
238 }
239
240 static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
241 struct extent_state *other)
242 {
243 if (tree->ops && tree->ops->merge_extent_hook)
244 tree->ops->merge_extent_hook(tree->mapping->host, new,
245 other);
246 }
247
248 /*
249 * utility function to look for merge candidates inside a given range.
250 * Any extents with matching state are merged together into a single
251 * extent in the tree. Extents with EXTENT_IO in their state field
252 * are not merged because the end_io handlers need to be able to do
253 * operations on them without sleeping (or doing allocations/splits).
254 *
255 * This should be called with the tree lock held.
256 */
257 static void merge_state(struct extent_io_tree *tree,
258 struct extent_state *state)
259 {
260 struct extent_state *other;
261 struct rb_node *other_node;
262
263 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
264 return;
265
266 other_node = rb_prev(&state->rb_node);
267 if (other_node) {
268 other = rb_entry(other_node, struct extent_state, rb_node);
269 if (other->end == state->start - 1 &&
270 other->state == state->state) {
271 merge_cb(tree, state, other);
272 state->start = other->start;
273 other->tree = NULL;
274 rb_erase(&other->rb_node, &tree->state);
275 free_extent_state(other);
276 }
277 }
278 other_node = rb_next(&state->rb_node);
279 if (other_node) {
280 other = rb_entry(other_node, struct extent_state, rb_node);
281 if (other->start == state->end + 1 &&
282 other->state == state->state) {
283 merge_cb(tree, state, other);
284 state->end = other->end;
285 other->tree = NULL;
286 rb_erase(&other->rb_node, &tree->state);
287 free_extent_state(other);
288 }
289 }
290 }
291
292 static void set_state_cb(struct extent_io_tree *tree,
293 struct extent_state *state, int *bits)
294 {
295 if (tree->ops && tree->ops->set_bit_hook)
296 tree->ops->set_bit_hook(tree->mapping->host, state, bits);
297 }
298
299 static void clear_state_cb(struct extent_io_tree *tree,
300 struct extent_state *state, int *bits)
301 {
302 if (tree->ops && tree->ops->clear_bit_hook)
303 tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
304 }
305
306 static void set_state_bits(struct extent_io_tree *tree,
307 struct extent_state *state, int *bits);
308
309 /*
310 * insert an extent_state struct into the tree. 'bits' are set on the
311 * struct before it is inserted.
312 *
313 * This may return -EEXIST if the extent is already there, in which case the
314 * state struct is freed.
315 *
316 * The tree lock is not taken internally. This is a utility function and
317 * probably isn't what you want to call (see set/clear_extent_bit).
318 */
319 static int insert_state(struct extent_io_tree *tree,
320 struct extent_state *state, u64 start, u64 end,
321 int *bits)
322 {
323 struct rb_node *node;
324
325 if (end < start) {
326 printk(KERN_ERR "btrfs end < start %llu %llu\n",
327 (unsigned long long)end,
328 (unsigned long long)start);
329 WARN_ON(1);
330 }
331 state->start = start;
332 state->end = end;
333
334 set_state_bits(tree, state, bits);
335
336 node = tree_insert(&tree->state, end, &state->rb_node);
337 if (node) {
338 struct extent_state *found;
339 found = rb_entry(node, struct extent_state, rb_node);
340 printk(KERN_ERR "btrfs found node %llu %llu on insert of "
341 "%llu %llu\n", (unsigned long long)found->start,
342 (unsigned long long)found->end,
343 (unsigned long long)start, (unsigned long long)end);
344 return -EEXIST;
345 }
346 state->tree = tree;
347 merge_state(tree, state);
348 return 0;
349 }
350
351 static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
352 u64 split)
353 {
354 if (tree->ops && tree->ops->split_extent_hook)
355 tree->ops->split_extent_hook(tree->mapping->host, orig, split);
356 }
357
358 /*
359 * split a given extent state struct in two, inserting the preallocated
360 * struct 'prealloc' as the newly created second half. 'split' indicates an
361 * offset inside 'orig' where it should be split.
362 *
363 * Before calling,
364 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
365 * are two extent state structs in the tree:
366 * prealloc: [orig->start, split - 1]
367 * orig: [ split, orig->end ]
368 *
369 * The tree locks are not taken by this function. They need to be held
370 * by the caller.
371 */
372 static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
373 struct extent_state *prealloc, u64 split)
374 {
375 struct rb_node *node;
376
377 split_cb(tree, orig, split);
378
379 prealloc->start = orig->start;
380 prealloc->end = split - 1;
381 prealloc->state = orig->state;
382 orig->start = split;
383
384 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
385 if (node) {
386 free_extent_state(prealloc);
387 return -EEXIST;
388 }
389 prealloc->tree = tree;
390 return 0;
391 }
392
393 /*
394 * utility function to clear some bits in an extent state struct.
395 * it will optionally wake up any one waiting on this state (wake == 1), or
396 * forcibly remove the state from the tree (delete == 1).
397 *
398 * If no bits are set on the state struct after clearing things, the
399 * struct is freed and removed from the tree
400 */
401 static int clear_state_bit(struct extent_io_tree *tree,
402 struct extent_state *state,
403 int *bits, int wake)
404 {
405 int bits_to_clear = *bits & ~EXTENT_CTLBITS;
406 int ret = state->state & bits_to_clear;
407
408 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
409 u64 range = state->end - state->start + 1;
410 WARN_ON(range > tree->dirty_bytes);
411 tree->dirty_bytes -= range;
412 }
413 clear_state_cb(tree, state, bits);
414 state->state &= ~bits_to_clear;
415 if (wake)
416 wake_up(&state->wq);
417 if (state->state == 0) {
418 if (state->tree) {
419 rb_erase(&state->rb_node, &tree->state);
420 state->tree = NULL;
421 free_extent_state(state);
422 } else {
423 WARN_ON(1);
424 }
425 } else {
426 merge_state(tree, state);
427 }
428 return ret;
429 }
430
431 static struct extent_state *
432 alloc_extent_state_atomic(struct extent_state *prealloc)
433 {
434 if (!prealloc)
435 prealloc = alloc_extent_state(GFP_ATOMIC);
436
437 return prealloc;
438 }
439
440 /*
441 * clear some bits on a range in the tree. This may require splitting
442 * or inserting elements in the tree, so the gfp mask is used to
443 * indicate which allocations or sleeping are allowed.
444 *
445 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
446 * the given range from the tree regardless of state (ie for truncate).
447 *
448 * the range [start, end] is inclusive.
449 *
450 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
451 * bits were already set, or zero if none of the bits were already set.
452 */
453 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
454 int bits, int wake, int delete,
455 struct extent_state **cached_state,
456 gfp_t mask)
457 {
458 struct extent_state *state;
459 struct extent_state *cached;
460 struct extent_state *prealloc = NULL;
461 struct rb_node *next_node;
462 struct rb_node *node;
463 u64 last_end;
464 int err;
465 int set = 0;
466 int clear = 0;
467
468 if (delete)
469 bits |= ~EXTENT_CTLBITS;
470 bits |= EXTENT_FIRST_DELALLOC;
471
472 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
473 clear = 1;
474 again:
475 if (!prealloc && (mask & __GFP_WAIT)) {
476 prealloc = alloc_extent_state(mask);
477 if (!prealloc)
478 return -ENOMEM;
479 }
480
481 spin_lock(&tree->lock);
482 if (cached_state) {
483 cached = *cached_state;
484
485 if (clear) {
486 *cached_state = NULL;
487 cached_state = NULL;
488 }
489
490 if (cached && cached->tree && cached->start <= start &&
491 cached->end > start) {
492 if (clear)
493 atomic_dec(&cached->refs);
494 state = cached;
495 goto hit_next;
496 }
497 if (clear)
498 free_extent_state(cached);
499 }
500 /*
501 * this search will find the extents that end after
502 * our range starts
503 */
504 node = tree_search(tree, start);
505 if (!node)
506 goto out;
507 state = rb_entry(node, struct extent_state, rb_node);
508 hit_next:
509 if (state->start > end)
510 goto out;
511 WARN_ON(state->end < start);
512 last_end = state->end;
513
514 /*
515 * | ---- desired range ---- |
516 * | state | or
517 * | ------------- state -------------- |
518 *
519 * We need to split the extent we found, and may flip
520 * bits on second half.
521 *
522 * If the extent we found extends past our range, we
523 * just split and search again. It'll get split again
524 * the next time though.
525 *
526 * If the extent we found is inside our range, we clear
527 * the desired bit on it.
528 */
529
530 if (state->start < start) {
531 prealloc = alloc_extent_state_atomic(prealloc);
532 BUG_ON(!prealloc);
533 err = split_state(tree, state, prealloc, start);
534 BUG_ON(err == -EEXIST);
535 prealloc = NULL;
536 if (err)
537 goto out;
538 if (state->end <= end) {
539 set |= clear_state_bit(tree, state, &bits, wake);
540 if (last_end == (u64)-1)
541 goto out;
542 start = last_end + 1;
543 }
544 goto search_again;
545 }
546 /*
547 * | ---- desired range ---- |
548 * | state |
549 * We need to split the extent, and clear the bit
550 * on the first half
551 */
552 if (state->start <= end && state->end > end) {
553 prealloc = alloc_extent_state_atomic(prealloc);
554 BUG_ON(!prealloc);
555 err = split_state(tree, state, prealloc, end + 1);
556 BUG_ON(err == -EEXIST);
557 if (wake)
558 wake_up(&state->wq);
559
560 set |= clear_state_bit(tree, prealloc, &bits, wake);
561
562 prealloc = NULL;
563 goto out;
564 }
565
566 if (state->end < end && prealloc && !need_resched())
567 next_node = rb_next(&state->rb_node);
568 else
569 next_node = NULL;
570
571 set |= clear_state_bit(tree, state, &bits, wake);
572 if (last_end == (u64)-1)
573 goto out;
574 start = last_end + 1;
575 if (start <= end && next_node) {
576 state = rb_entry(next_node, struct extent_state,
577 rb_node);
578 if (state->start == start)
579 goto hit_next;
580 }
581 goto search_again;
582
583 out:
584 spin_unlock(&tree->lock);
585 if (prealloc)
586 free_extent_state(prealloc);
587
588 return set;
589
590 search_again:
591 if (start > end)
592 goto out;
593 spin_unlock(&tree->lock);
594 if (mask & __GFP_WAIT)
595 cond_resched();
596 goto again;
597 }
598
599 static int wait_on_state(struct extent_io_tree *tree,
600 struct extent_state *state)
601 __releases(tree->lock)
602 __acquires(tree->lock)
603 {
604 DEFINE_WAIT(wait);
605 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
606 spin_unlock(&tree->lock);
607 schedule();
608 spin_lock(&tree->lock);
609 finish_wait(&state->wq, &wait);
610 return 0;
611 }
612
613 /*
614 * waits for one or more bits to clear on a range in the state tree.
615 * The range [start, end] is inclusive.
616 * The tree lock is taken by this function
617 */
618 int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
619 {
620 struct extent_state *state;
621 struct rb_node *node;
622
623 spin_lock(&tree->lock);
624 again:
625 while (1) {
626 /*
627 * this search will find all the extents that end after
628 * our range starts
629 */
630 node = tree_search(tree, start);
631 if (!node)
632 break;
633
634 state = rb_entry(node, struct extent_state, rb_node);
635
636 if (state->start > end)
637 goto out;
638
639 if (state->state & bits) {
640 start = state->start;
641 atomic_inc(&state->refs);
642 wait_on_state(tree, state);
643 free_extent_state(state);
644 goto again;
645 }
646 start = state->end + 1;
647
648 if (start > end)
649 break;
650
651 if (need_resched()) {
652 spin_unlock(&tree->lock);
653 cond_resched();
654 spin_lock(&tree->lock);
655 }
656 }
657 out:
658 spin_unlock(&tree->lock);
659 return 0;
660 }
661
662 static void set_state_bits(struct extent_io_tree *tree,
663 struct extent_state *state,
664 int *bits)
665 {
666 int bits_to_set = *bits & ~EXTENT_CTLBITS;
667
668 set_state_cb(tree, state, bits);
669 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
670 u64 range = state->end - state->start + 1;
671 tree->dirty_bytes += range;
672 }
673 state->state |= bits_to_set;
674 }
675
676 static void cache_state(struct extent_state *state,
677 struct extent_state **cached_ptr)
678 {
679 if (cached_ptr && !(*cached_ptr)) {
680 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
681 *cached_ptr = state;
682 atomic_inc(&state->refs);
683 }
684 }
685 }
686
687 static void uncache_state(struct extent_state **cached_ptr)
688 {
689 if (cached_ptr && (*cached_ptr)) {
690 struct extent_state *state = *cached_ptr;
691 *cached_ptr = NULL;
692 free_extent_state(state);
693 }
694 }
695
696 /*
697 * set some bits on a range in the tree. This may require allocations or
698 * sleeping, so the gfp mask is used to indicate what is allowed.
699 *
700 * If any of the exclusive bits are set, this will fail with -EEXIST if some
701 * part of the range already has the desired bits set. The start of the
702 * existing range is returned in failed_start in this case.
703 *
704 * [start, end] is inclusive This takes the tree lock.
705 */
706
707 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
708 int bits, int exclusive_bits, u64 *failed_start,
709 struct extent_state **cached_state, gfp_t mask)
710 {
711 struct extent_state *state;
712 struct extent_state *prealloc = NULL;
713 struct rb_node *node;
714 int err = 0;
715 u64 last_start;
716 u64 last_end;
717
718 bits |= EXTENT_FIRST_DELALLOC;
719 again:
720 if (!prealloc && (mask & __GFP_WAIT)) {
721 prealloc = alloc_extent_state(mask);
722 BUG_ON(!prealloc);
723 }
724
725 spin_lock(&tree->lock);
726 if (cached_state && *cached_state) {
727 state = *cached_state;
728 if (state->start <= start && state->end > start &&
729 state->tree) {
730 node = &state->rb_node;
731 goto hit_next;
732 }
733 }
734 /*
735 * this search will find all the extents that end after
736 * our range starts.
737 */
738 node = tree_search(tree, start);
739 if (!node) {
740 prealloc = alloc_extent_state_atomic(prealloc);
741 BUG_ON(!prealloc);
742 err = insert_state(tree, prealloc, start, end, &bits);
743 prealloc = NULL;
744 BUG_ON(err == -EEXIST);
745 goto out;
746 }
747 state = rb_entry(node, struct extent_state, rb_node);
748 hit_next:
749 last_start = state->start;
750 last_end = state->end;
751
752 /*
753 * | ---- desired range ---- |
754 * | state |
755 *
756 * Just lock what we found and keep going
757 */
758 if (state->start == start && state->end <= end) {
759 struct rb_node *next_node;
760 if (state->state & exclusive_bits) {
761 *failed_start = state->start;
762 err = -EEXIST;
763 goto out;
764 }
765
766 set_state_bits(tree, state, &bits);
767
768 cache_state(state, cached_state);
769 merge_state(tree, state);
770 if (last_end == (u64)-1)
771 goto out;
772
773 start = last_end + 1;
774 next_node = rb_next(&state->rb_node);
775 if (next_node && start < end && prealloc && !need_resched()) {
776 state = rb_entry(next_node, struct extent_state,
777 rb_node);
778 if (state->start == start)
779 goto hit_next;
780 }
781 goto search_again;
782 }
783
784 /*
785 * | ---- desired range ---- |
786 * | state |
787 * or
788 * | ------------- state -------------- |
789 *
790 * We need to split the extent we found, and may flip bits on
791 * second half.
792 *
793 * If the extent we found extends past our
794 * range, we just split and search again. It'll get split
795 * again the next time though.
796 *
797 * If the extent we found is inside our range, we set the
798 * desired bit on it.
799 */
800 if (state->start < start) {
801 if (state->state & exclusive_bits) {
802 *failed_start = start;
803 err = -EEXIST;
804 goto out;
805 }
806
807 prealloc = alloc_extent_state_atomic(prealloc);
808 BUG_ON(!prealloc);
809 err = split_state(tree, state, prealloc, start);
810 BUG_ON(err == -EEXIST);
811 prealloc = NULL;
812 if (err)
813 goto out;
814 if (state->end <= end) {
815 set_state_bits(tree, state, &bits);
816 cache_state(state, cached_state);
817 merge_state(tree, state);
818 if (last_end == (u64)-1)
819 goto out;
820 start = last_end + 1;
821 }
822 goto search_again;
823 }
824 /*
825 * | ---- desired range ---- |
826 * | state | or | state |
827 *
828 * There's a hole, we need to insert something in it and
829 * ignore the extent we found.
830 */
831 if (state->start > start) {
832 u64 this_end;
833 if (end < last_start)
834 this_end = end;
835 else
836 this_end = last_start - 1;
837
838 prealloc = alloc_extent_state_atomic(prealloc);
839 BUG_ON(!prealloc);
840
841 /*
842 * Avoid to free 'prealloc' if it can be merged with
843 * the later extent.
844 */
845 err = insert_state(tree, prealloc, start, this_end,
846 &bits);
847 BUG_ON(err == -EEXIST);
848 if (err) {
849 free_extent_state(prealloc);
850 prealloc = NULL;
851 goto out;
852 }
853 cache_state(prealloc, cached_state);
854 prealloc = NULL;
855 start = this_end + 1;
856 goto search_again;
857 }
858 /*
859 * | ---- desired range ---- |
860 * | state |
861 * We need to split the extent, and set the bit
862 * on the first half
863 */
864 if (state->start <= end && state->end > end) {
865 if (state->state & exclusive_bits) {
866 *failed_start = start;
867 err = -EEXIST;
868 goto out;
869 }
870
871 prealloc = alloc_extent_state_atomic(prealloc);
872 BUG_ON(!prealloc);
873 err = split_state(tree, state, prealloc, end + 1);
874 BUG_ON(err == -EEXIST);
875
876 set_state_bits(tree, prealloc, &bits);
877 cache_state(prealloc, cached_state);
878 merge_state(tree, prealloc);
879 prealloc = NULL;
880 goto out;
881 }
882
883 goto search_again;
884
885 out:
886 spin_unlock(&tree->lock);
887 if (prealloc)
888 free_extent_state(prealloc);
889
890 return err;
891
892 search_again:
893 if (start > end)
894 goto out;
895 spin_unlock(&tree->lock);
896 if (mask & __GFP_WAIT)
897 cond_resched();
898 goto again;
899 }
900
901 /* wrappers around set/clear extent bit */
902 int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
903 gfp_t mask)
904 {
905 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
906 NULL, mask);
907 }
908
909 int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
910 int bits, gfp_t mask)
911 {
912 return set_extent_bit(tree, start, end, bits, 0, NULL,
913 NULL, mask);
914 }
915
916 int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
917 int bits, gfp_t mask)
918 {
919 return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
920 }
921
922 int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
923 struct extent_state **cached_state, gfp_t mask)
924 {
925 return set_extent_bit(tree, start, end,
926 EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
927 0, NULL, cached_state, mask);
928 }
929
930 int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
931 gfp_t mask)
932 {
933 return clear_extent_bit(tree, start, end,
934 EXTENT_DIRTY | EXTENT_DELALLOC |
935 EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
936 }
937
938 int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
939 gfp_t mask)
940 {
941 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
942 NULL, mask);
943 }
944
945 int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
946 struct extent_state **cached_state, gfp_t mask)
947 {
948 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0,
949 NULL, cached_state, mask);
950 }
951
952 static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
953 u64 end, struct extent_state **cached_state,
954 gfp_t mask)
955 {
956 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
957 cached_state, mask);
958 }
959
960 /*
961 * either insert or lock state struct between start and end use mask to tell
962 * us if waiting is desired.
963 */
964 int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
965 int bits, struct extent_state **cached_state, gfp_t mask)
966 {
967 int err;
968 u64 failed_start;
969 while (1) {
970 err = set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
971 EXTENT_LOCKED, &failed_start,
972 cached_state, mask);
973 if (err == -EEXIST && (mask & __GFP_WAIT)) {
974 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
975 start = failed_start;
976 } else {
977 break;
978 }
979 WARN_ON(start > end);
980 }
981 return err;
982 }
983
984 int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
985 {
986 return lock_extent_bits(tree, start, end, 0, NULL, mask);
987 }
988
989 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
990 gfp_t mask)
991 {
992 int err;
993 u64 failed_start;
994
995 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
996 &failed_start, NULL, mask);
997 if (err == -EEXIST) {
998 if (failed_start > start)
999 clear_extent_bit(tree, start, failed_start - 1,
1000 EXTENT_LOCKED, 1, 0, NULL, mask);
1001 return 0;
1002 }
1003 return 1;
1004 }
1005
1006 int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
1007 struct extent_state **cached, gfp_t mask)
1008 {
1009 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
1010 mask);
1011 }
1012
1013 int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
1014 {
1015 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1016 mask);
1017 }
1018
1019 /*
1020 * helper function to set both pages and extents in the tree writeback
1021 */
1022 static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1023 {
1024 unsigned long index = start >> PAGE_CACHE_SHIFT;
1025 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1026 struct page *page;
1027
1028 while (index <= end_index) {
1029 page = find_get_page(tree->mapping, index);
1030 BUG_ON(!page);
1031 set_page_writeback(page);
1032 page_cache_release(page);
1033 index++;
1034 }
1035 return 0;
1036 }
1037
1038 /*
1039 * find the first offset in the io tree with 'bits' set. zero is
1040 * returned if we find something, and *start_ret and *end_ret are
1041 * set to reflect the state struct that was found.
1042 *
1043 * If nothing was found, 1 is returned, < 0 on error
1044 */
1045 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1046 u64 *start_ret, u64 *end_ret, int bits)
1047 {
1048 struct rb_node *node;
1049 struct extent_state *state;
1050 int ret = 1;
1051
1052 spin_lock(&tree->lock);
1053 /*
1054 * this search will find all the extents that end after
1055 * our range starts.
1056 */
1057 node = tree_search(tree, start);
1058 if (!node)
1059 goto out;
1060
1061 while (1) {
1062 state = rb_entry(node, struct extent_state, rb_node);
1063 if (state->end >= start && (state->state & bits)) {
1064 *start_ret = state->start;
1065 *end_ret = state->end;
1066 ret = 0;
1067 break;
1068 }
1069 node = rb_next(node);
1070 if (!node)
1071 break;
1072 }
1073 out:
1074 spin_unlock(&tree->lock);
1075 return ret;
1076 }
1077
1078 /* find the first state struct with 'bits' set after 'start', and
1079 * return it. tree->lock must be held. NULL will returned if
1080 * nothing was found after 'start'
1081 */
1082 struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
1083 u64 start, int bits)
1084 {
1085 struct rb_node *node;
1086 struct extent_state *state;
1087
1088 /*
1089 * this search will find all the extents that end after
1090 * our range starts.
1091 */
1092 node = tree_search(tree, start);
1093 if (!node)
1094 goto out;
1095
1096 while (1) {
1097 state = rb_entry(node, struct extent_state, rb_node);
1098 if (state->end >= start && (state->state & bits))
1099 return state;
1100
1101 node = rb_next(node);
1102 if (!node)
1103 break;
1104 }
1105 out:
1106 return NULL;
1107 }
1108
1109 /*
1110 * find a contiguous range of bytes in the file marked as delalloc, not
1111 * more than 'max_bytes'. start and end are used to return the range,
1112 *
1113 * 1 is returned if we find something, 0 if nothing was in the tree
1114 */
1115 static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1116 u64 *start, u64 *end, u64 max_bytes,
1117 struct extent_state **cached_state)
1118 {
1119 struct rb_node *node;
1120 struct extent_state *state;
1121 u64 cur_start = *start;
1122 u64 found = 0;
1123 u64 total_bytes = 0;
1124
1125 spin_lock(&tree->lock);
1126
1127 /*
1128 * this search will find all the extents that end after
1129 * our range starts.
1130 */
1131 node = tree_search(tree, cur_start);
1132 if (!node) {
1133 if (!found)
1134 *end = (u64)-1;
1135 goto out;
1136 }
1137
1138 while (1) {
1139 state = rb_entry(node, struct extent_state, rb_node);
1140 if (found && (state->start != cur_start ||
1141 (state->state & EXTENT_BOUNDARY))) {
1142 goto out;
1143 }
1144 if (!(state->state & EXTENT_DELALLOC)) {
1145 if (!found)
1146 *end = state->end;
1147 goto out;
1148 }
1149 if (!found) {
1150 *start = state->start;
1151 *cached_state = state;
1152 atomic_inc(&state->refs);
1153 }
1154 found++;
1155 *end = state->end;
1156 cur_start = state->end + 1;
1157 node = rb_next(node);
1158 if (!node)
1159 break;
1160 total_bytes += state->end - state->start + 1;
1161 if (total_bytes >= max_bytes)
1162 break;
1163 }
1164 out:
1165 spin_unlock(&tree->lock);
1166 return found;
1167 }
1168
1169 static noinline int __unlock_for_delalloc(struct inode *inode,
1170 struct page *locked_page,
1171 u64 start, u64 end)
1172 {
1173 int ret;
1174 struct page *pages[16];
1175 unsigned long index = start >> PAGE_CACHE_SHIFT;
1176 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1177 unsigned long nr_pages = end_index - index + 1;
1178 int i;
1179
1180 if (index == locked_page->index && end_index == index)
1181 return 0;
1182
1183 while (nr_pages > 0) {
1184 ret = find_get_pages_contig(inode->i_mapping, index,
1185 min_t(unsigned long, nr_pages,
1186 ARRAY_SIZE(pages)), pages);
1187 for (i = 0; i < ret; i++) {
1188 if (pages[i] != locked_page)
1189 unlock_page(pages[i]);
1190 page_cache_release(pages[i]);
1191 }
1192 nr_pages -= ret;
1193 index += ret;
1194 cond_resched();
1195 }
1196 return 0;
1197 }
1198
1199 static noinline int lock_delalloc_pages(struct inode *inode,
1200 struct page *locked_page,
1201 u64 delalloc_start,
1202 u64 delalloc_end)
1203 {
1204 unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
1205 unsigned long start_index = index;
1206 unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
1207 unsigned long pages_locked = 0;
1208 struct page *pages[16];
1209 unsigned long nrpages;
1210 int ret;
1211 int i;
1212
1213 /* the caller is responsible for locking the start index */
1214 if (index == locked_page->index && index == end_index)
1215 return 0;
1216
1217 /* skip the page at the start index */
1218 nrpages = end_index - index + 1;
1219 while (nrpages > 0) {
1220 ret = find_get_pages_contig(inode->i_mapping, index,
1221 min_t(unsigned long,
1222 nrpages, ARRAY_SIZE(pages)), pages);
1223 if (ret == 0) {
1224 ret = -EAGAIN;
1225 goto done;
1226 }
1227 /* now we have an array of pages, lock them all */
1228 for (i = 0; i < ret; i++) {
1229 /*
1230 * the caller is taking responsibility for
1231 * locked_page
1232 */
1233 if (pages[i] != locked_page) {
1234 lock_page(pages[i]);
1235 if (!PageDirty(pages[i]) ||
1236 pages[i]->mapping != inode->i_mapping) {
1237 ret = -EAGAIN;
1238 unlock_page(pages[i]);
1239 page_cache_release(pages[i]);
1240 goto done;
1241 }
1242 }
1243 page_cache_release(pages[i]);
1244 pages_locked++;
1245 }
1246 nrpages -= ret;
1247 index += ret;
1248 cond_resched();
1249 }
1250 ret = 0;
1251 done:
1252 if (ret && pages_locked) {
1253 __unlock_for_delalloc(inode, locked_page,
1254 delalloc_start,
1255 ((u64)(start_index + pages_locked - 1)) <<
1256 PAGE_CACHE_SHIFT);
1257 }
1258 return ret;
1259 }
1260
1261 /*
1262 * find a contiguous range of bytes in the file marked as delalloc, not
1263 * more than 'max_bytes'. start and end are used to return the range,
1264 *
1265 * 1 is returned if we find something, 0 if nothing was in the tree
1266 */
1267 static noinline u64 find_lock_delalloc_range(struct inode *inode,
1268 struct extent_io_tree *tree,
1269 struct page *locked_page,
1270 u64 *start, u64 *end,
1271 u64 max_bytes)
1272 {
1273 u64 delalloc_start;
1274 u64 delalloc_end;
1275 u64 found;
1276 struct extent_state *cached_state = NULL;
1277 int ret;
1278 int loops = 0;
1279
1280 again:
1281 /* step one, find a bunch of delalloc bytes starting at start */
1282 delalloc_start = *start;
1283 delalloc_end = 0;
1284 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1285 max_bytes, &cached_state);
1286 if (!found || delalloc_end <= *start) {
1287 *start = delalloc_start;
1288 *end = delalloc_end;
1289 free_extent_state(cached_state);
1290 return found;
1291 }
1292
1293 /*
1294 * start comes from the offset of locked_page. We have to lock
1295 * pages in order, so we can't process delalloc bytes before
1296 * locked_page
1297 */
1298 if (delalloc_start < *start)
1299 delalloc_start = *start;
1300
1301 /*
1302 * make sure to limit the number of pages we try to lock down
1303 * if we're looping.
1304 */
1305 if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1306 delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
1307
1308 /* step two, lock all the pages after the page that has start */
1309 ret = lock_delalloc_pages(inode, locked_page,
1310 delalloc_start, delalloc_end);
1311 if (ret == -EAGAIN) {
1312 /* some of the pages are gone, lets avoid looping by
1313 * shortening the size of the delalloc range we're searching
1314 */
1315 free_extent_state(cached_state);
1316 if (!loops) {
1317 unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
1318 max_bytes = PAGE_CACHE_SIZE - offset;
1319 loops = 1;
1320 goto again;
1321 } else {
1322 found = 0;
1323 goto out_failed;
1324 }
1325 }
1326 BUG_ON(ret);
1327
1328 /* step three, lock the state bits for the whole range */
1329 lock_extent_bits(tree, delalloc_start, delalloc_end,
1330 0, &cached_state, GFP_NOFS);
1331
1332 /* then test to make sure it is all still delalloc */
1333 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1334 EXTENT_DELALLOC, 1, cached_state);
1335 if (!ret) {
1336 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1337 &cached_state, GFP_NOFS);
1338 __unlock_for_delalloc(inode, locked_page,
1339 delalloc_start, delalloc_end);
1340 cond_resched();
1341 goto again;
1342 }
1343 free_extent_state(cached_state);
1344 *start = delalloc_start;
1345 *end = delalloc_end;
1346 out_failed:
1347 return found;
1348 }
1349
1350 int extent_clear_unlock_delalloc(struct inode *inode,
1351 struct extent_io_tree *tree,
1352 u64 start, u64 end, struct page *locked_page,
1353 unsigned long op)
1354 {
1355 int ret;
1356 struct page *pages[16];
1357 unsigned long index = start >> PAGE_CACHE_SHIFT;
1358 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1359 unsigned long nr_pages = end_index - index + 1;
1360 int i;
1361 int clear_bits = 0;
1362
1363 if (op & EXTENT_CLEAR_UNLOCK)
1364 clear_bits |= EXTENT_LOCKED;
1365 if (op & EXTENT_CLEAR_DIRTY)
1366 clear_bits |= EXTENT_DIRTY;
1367
1368 if (op & EXTENT_CLEAR_DELALLOC)
1369 clear_bits |= EXTENT_DELALLOC;
1370
1371 clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1372 if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
1373 EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
1374 EXTENT_SET_PRIVATE2)))
1375 return 0;
1376
1377 while (nr_pages > 0) {
1378 ret = find_get_pages_contig(inode->i_mapping, index,
1379 min_t(unsigned long,
1380 nr_pages, ARRAY_SIZE(pages)), pages);
1381 for (i = 0; i < ret; i++) {
1382
1383 if (op & EXTENT_SET_PRIVATE2)
1384 SetPagePrivate2(pages[i]);
1385
1386 if (pages[i] == locked_page) {
1387 page_cache_release(pages[i]);
1388 continue;
1389 }
1390 if (op & EXTENT_CLEAR_DIRTY)
1391 clear_page_dirty_for_io(pages[i]);
1392 if (op & EXTENT_SET_WRITEBACK)
1393 set_page_writeback(pages[i]);
1394 if (op & EXTENT_END_WRITEBACK)
1395 end_page_writeback(pages[i]);
1396 if (op & EXTENT_CLEAR_UNLOCK_PAGE)
1397 unlock_page(pages[i]);
1398 page_cache_release(pages[i]);
1399 }
1400 nr_pages -= ret;
1401 index += ret;
1402 cond_resched();
1403 }
1404 return 0;
1405 }
1406
1407 /*
1408 * count the number of bytes in the tree that have a given bit(s)
1409 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1410 * cached. The total number found is returned.
1411 */
1412 u64 count_range_bits(struct extent_io_tree *tree,
1413 u64 *start, u64 search_end, u64 max_bytes,
1414 unsigned long bits, int contig)
1415 {
1416 struct rb_node *node;
1417 struct extent_state *state;
1418 u64 cur_start = *start;
1419 u64 total_bytes = 0;
1420 u64 last = 0;
1421 int found = 0;
1422
1423 if (search_end <= cur_start) {
1424 WARN_ON(1);
1425 return 0;
1426 }
1427
1428 spin_lock(&tree->lock);
1429 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1430 total_bytes = tree->dirty_bytes;
1431 goto out;
1432 }
1433 /*
1434 * this search will find all the extents that end after
1435 * our range starts.
1436 */
1437 node = tree_search(tree, cur_start);
1438 if (!node)
1439 goto out;
1440
1441 while (1) {
1442 state = rb_entry(node, struct extent_state, rb_node);
1443 if (state->start > search_end)
1444 break;
1445 if (contig && found && state->start > last + 1)
1446 break;
1447 if (state->end >= cur_start && (state->state & bits) == bits) {
1448 total_bytes += min(search_end, state->end) + 1 -
1449 max(cur_start, state->start);
1450 if (total_bytes >= max_bytes)
1451 break;
1452 if (!found) {
1453 *start = max(cur_start, state->start);
1454 found = 1;
1455 }
1456 last = state->end;
1457 } else if (contig && found) {
1458 break;
1459 }
1460 node = rb_next(node);
1461 if (!node)
1462 break;
1463 }
1464 out:
1465 spin_unlock(&tree->lock);
1466 return total_bytes;
1467 }
1468
1469 /*
1470 * set the private field for a given byte offset in the tree. If there isn't
1471 * an extent_state there already, this does nothing.
1472 */
1473 int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1474 {
1475 struct rb_node *node;
1476 struct extent_state *state;
1477 int ret = 0;
1478
1479 spin_lock(&tree->lock);
1480 /*
1481 * this search will find all the extents that end after
1482 * our range starts.
1483 */
1484 node = tree_search(tree, start);
1485 if (!node) {
1486 ret = -ENOENT;
1487 goto out;
1488 }
1489 state = rb_entry(node, struct extent_state, rb_node);
1490 if (state->start != start) {
1491 ret = -ENOENT;
1492 goto out;
1493 }
1494 state->private = private;
1495 out:
1496 spin_unlock(&tree->lock);
1497 return ret;
1498 }
1499
1500 int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1501 {
1502 struct rb_node *node;
1503 struct extent_state *state;
1504 int ret = 0;
1505
1506 spin_lock(&tree->lock);
1507 /*
1508 * this search will find all the extents that end after
1509 * our range starts.
1510 */
1511 node = tree_search(tree, start);
1512 if (!node) {
1513 ret = -ENOENT;
1514 goto out;
1515 }
1516 state = rb_entry(node, struct extent_state, rb_node);
1517 if (state->start != start) {
1518 ret = -ENOENT;
1519 goto out;
1520 }
1521 *private = state->private;
1522 out:
1523 spin_unlock(&tree->lock);
1524 return ret;
1525 }
1526
1527 /*
1528 * searches a range in the state tree for a given mask.
1529 * If 'filled' == 1, this returns 1 only if every extent in the tree
1530 * has the bits set. Otherwise, 1 is returned if any bit in the
1531 * range is found set.
1532 */
1533 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1534 int bits, int filled, struct extent_state *cached)
1535 {
1536 struct extent_state *state = NULL;
1537 struct rb_node *node;
1538 int bitset = 0;
1539
1540 spin_lock(&tree->lock);
1541 if (cached && cached->tree && cached->start <= start &&
1542 cached->end > start)
1543 node = &cached->rb_node;
1544 else
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
1566 if (state->end == (u64)-1)
1567 break;
1568
1569 start = state->end + 1;
1570 if (start > end)
1571 break;
1572 node = rb_next(node);
1573 if (!node) {
1574 if (filled)
1575 bitset = 0;
1576 break;
1577 }
1578 }
1579 spin_unlock(&tree->lock);
1580 return bitset;
1581 }
1582
1583 /*
1584 * helper function to set a given page up to date if all the
1585 * extents in the tree for that page are up to date
1586 */
1587 static int check_page_uptodate(struct extent_io_tree *tree,
1588 struct page *page)
1589 {
1590 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1591 u64 end = start + PAGE_CACHE_SIZE - 1;
1592 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1593 SetPageUptodate(page);
1594 return 0;
1595 }
1596
1597 /*
1598 * helper function to unlock a page if all the extents in the tree
1599 * for that page are unlocked
1600 */
1601 static int check_page_locked(struct extent_io_tree *tree,
1602 struct page *page)
1603 {
1604 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1605 u64 end = start + PAGE_CACHE_SIZE - 1;
1606 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
1607 unlock_page(page);
1608 return 0;
1609 }
1610
1611 /*
1612 * helper function to end page writeback if all the extents
1613 * in the tree for that page are done with writeback
1614 */
1615 static int check_page_writeback(struct extent_io_tree *tree,
1616 struct page *page)
1617 {
1618 end_page_writeback(page);
1619 return 0;
1620 }
1621
1622 /* lots and lots of room for performance fixes in the end_bio funcs */
1623
1624 /*
1625 * after a writepage IO is done, we need to:
1626 * clear the uptodate bits on error
1627 * clear the writeback bits in the extent tree for this IO
1628 * end_page_writeback if the page has no more pending IO
1629 *
1630 * Scheduling is not allowed, so the extent state tree is expected
1631 * to have one and only one object corresponding to this IO.
1632 */
1633 static void end_bio_extent_writepage(struct bio *bio, int err)
1634 {
1635 int uptodate = err == 0;
1636 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1637 struct extent_io_tree *tree;
1638 u64 start;
1639 u64 end;
1640 int whole_page;
1641 int ret;
1642
1643 do {
1644 struct page *page = bvec->bv_page;
1645 tree = &BTRFS_I(page->mapping->host)->io_tree;
1646
1647 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1648 bvec->bv_offset;
1649 end = start + bvec->bv_len - 1;
1650
1651 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1652 whole_page = 1;
1653 else
1654 whole_page = 0;
1655
1656 if (--bvec >= bio->bi_io_vec)
1657 prefetchw(&bvec->bv_page->flags);
1658 if (tree->ops && tree->ops->writepage_end_io_hook) {
1659 ret = tree->ops->writepage_end_io_hook(page, start,
1660 end, NULL, uptodate);
1661 if (ret)
1662 uptodate = 0;
1663 }
1664
1665 if (!uptodate && tree->ops &&
1666 tree->ops->writepage_io_failed_hook) {
1667 ret = tree->ops->writepage_io_failed_hook(bio, page,
1668 start, end, NULL);
1669 if (ret == 0) {
1670 uptodate = (err == 0);
1671 continue;
1672 }
1673 }
1674
1675 if (!uptodate) {
1676 clear_extent_uptodate(tree, start, end, NULL, GFP_NOFS);
1677 ClearPageUptodate(page);
1678 SetPageError(page);
1679 }
1680
1681 if (whole_page)
1682 end_page_writeback(page);
1683 else
1684 check_page_writeback(tree, page);
1685 } while (bvec >= bio->bi_io_vec);
1686
1687 bio_put(bio);
1688 }
1689
1690 /*
1691 * after a readpage IO is done, we need to:
1692 * clear the uptodate bits on error
1693 * set the uptodate bits if things worked
1694 * set the page up to date if all extents in the tree are uptodate
1695 * clear the lock bit in the extent tree
1696 * unlock the page if there are no other extents locked for it
1697 *
1698 * Scheduling is not allowed, so the extent state tree is expected
1699 * to have one and only one object corresponding to this IO.
1700 */
1701 static void end_bio_extent_readpage(struct bio *bio, int err)
1702 {
1703 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1704 struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
1705 struct bio_vec *bvec = bio->bi_io_vec;
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 struct extent_state *cached = NULL;
1718 struct extent_state *state;
1719
1720 tree = &BTRFS_I(page->mapping->host)->io_tree;
1721
1722 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1723 bvec->bv_offset;
1724 end = start + bvec->bv_len - 1;
1725
1726 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1727 whole_page = 1;
1728 else
1729 whole_page = 0;
1730
1731 if (++bvec <= bvec_end)
1732 prefetchw(&bvec->bv_page->flags);
1733
1734 spin_lock(&tree->lock);
1735 state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
1736 if (state && state->start == start) {
1737 /*
1738 * take a reference on the state, unlock will drop
1739 * the ref
1740 */
1741 cache_state(state, &cached);
1742 }
1743 spin_unlock(&tree->lock);
1744
1745 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1746 ret = tree->ops->readpage_end_io_hook(page, start, end,
1747 state);
1748 if (ret)
1749 uptodate = 0;
1750 }
1751 if (!uptodate && tree->ops &&
1752 tree->ops->readpage_io_failed_hook) {
1753 ret = tree->ops->readpage_io_failed_hook(bio, page,
1754 start, end, NULL);
1755 if (ret == 0) {
1756 uptodate =
1757 test_bit(BIO_UPTODATE, &bio->bi_flags);
1758 if (err)
1759 uptodate = 0;
1760 uncache_state(&cached);
1761 continue;
1762 }
1763 }
1764
1765 if (uptodate) {
1766 set_extent_uptodate(tree, start, end, &cached,
1767 GFP_ATOMIC);
1768 }
1769 unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
1770
1771 if (whole_page) {
1772 if (uptodate) {
1773 SetPageUptodate(page);
1774 } else {
1775 ClearPageUptodate(page);
1776 SetPageError(page);
1777 }
1778 unlock_page(page);
1779 } else {
1780 if (uptodate) {
1781 check_page_uptodate(tree, page);
1782 } else {
1783 ClearPageUptodate(page);
1784 SetPageError(page);
1785 }
1786 check_page_locked(tree, page);
1787 }
1788 } while (bvec <= bvec_end);
1789
1790 bio_put(bio);
1791 }
1792
1793 struct bio *
1794 btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
1795 gfp_t gfp_flags)
1796 {
1797 struct bio *bio;
1798
1799 bio = bio_alloc(gfp_flags, nr_vecs);
1800
1801 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
1802 while (!bio && (nr_vecs /= 2))
1803 bio = bio_alloc(gfp_flags, nr_vecs);
1804 }
1805
1806 if (bio) {
1807 bio->bi_size = 0;
1808 bio->bi_bdev = bdev;
1809 bio->bi_sector = first_sector;
1810 }
1811 return bio;
1812 }
1813
1814 static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
1815 unsigned long bio_flags)
1816 {
1817 int ret = 0;
1818 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1819 struct page *page = bvec->bv_page;
1820 struct extent_io_tree *tree = bio->bi_private;
1821 u64 start;
1822
1823 start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1824
1825 bio->bi_private = NULL;
1826
1827 bio_get(bio);
1828
1829 if (tree->ops && tree->ops->submit_bio_hook)
1830 ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1831 mirror_num, bio_flags, start);
1832 else
1833 submit_bio(rw, bio);
1834 if (bio_flagged(bio, BIO_EOPNOTSUPP))
1835 ret = -EOPNOTSUPP;
1836 bio_put(bio);
1837 return ret;
1838 }
1839
1840 static int submit_extent_page(int rw, struct extent_io_tree *tree,
1841 struct page *page, sector_t sector,
1842 size_t size, unsigned long offset,
1843 struct block_device *bdev,
1844 struct bio **bio_ret,
1845 unsigned long max_pages,
1846 bio_end_io_t end_io_func,
1847 int mirror_num,
1848 unsigned long prev_bio_flags,
1849 unsigned long bio_flags)
1850 {
1851 int ret = 0;
1852 struct bio *bio;
1853 int nr;
1854 int contig = 0;
1855 int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
1856 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
1857 size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
1858
1859 if (bio_ret && *bio_ret) {
1860 bio = *bio_ret;
1861 if (old_compressed)
1862 contig = bio->bi_sector == sector;
1863 else
1864 contig = bio->bi_sector + (bio->bi_size >> 9) ==
1865 sector;
1866
1867 if (prev_bio_flags != bio_flags || !contig ||
1868 (tree->ops && tree->ops->merge_bio_hook &&
1869 tree->ops->merge_bio_hook(page, offset, page_size, bio,
1870 bio_flags)) ||
1871 bio_add_page(bio, page, page_size, offset) < page_size) {
1872 ret = submit_one_bio(rw, bio, mirror_num,
1873 prev_bio_flags);
1874 bio = NULL;
1875 } else {
1876 return 0;
1877 }
1878 }
1879 if (this_compressed)
1880 nr = BIO_MAX_PAGES;
1881 else
1882 nr = bio_get_nr_vecs(bdev);
1883
1884 bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1885 if (!bio)
1886 return -ENOMEM;
1887
1888 bio_add_page(bio, page, page_size, offset);
1889 bio->bi_end_io = end_io_func;
1890 bio->bi_private = tree;
1891
1892 if (bio_ret)
1893 *bio_ret = bio;
1894 else
1895 ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
1896
1897 return ret;
1898 }
1899
1900 void set_page_extent_mapped(struct page *page)
1901 {
1902 if (!PagePrivate(page)) {
1903 SetPagePrivate(page);
1904 page_cache_get(page);
1905 set_page_private(page, EXTENT_PAGE_PRIVATE);
1906 }
1907 }
1908
1909 static void set_page_extent_head(struct page *page, unsigned long len)
1910 {
1911 WARN_ON(!PagePrivate(page));
1912 set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
1913 }
1914
1915 /*
1916 * basic readpage implementation. Locked extent state structs are inserted
1917 * into the tree that are removed when the IO is done (by the end_io
1918 * handlers)
1919 */
1920 static int __extent_read_full_page(struct extent_io_tree *tree,
1921 struct page *page,
1922 get_extent_t *get_extent,
1923 struct bio **bio, int mirror_num,
1924 unsigned long *bio_flags)
1925 {
1926 struct inode *inode = page->mapping->host;
1927 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1928 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1929 u64 end;
1930 u64 cur = start;
1931 u64 extent_offset;
1932 u64 last_byte = i_size_read(inode);
1933 u64 block_start;
1934 u64 cur_end;
1935 sector_t sector;
1936 struct extent_map *em;
1937 struct block_device *bdev;
1938 struct btrfs_ordered_extent *ordered;
1939 int ret;
1940 int nr = 0;
1941 size_t pg_offset = 0;
1942 size_t iosize;
1943 size_t disk_io_size;
1944 size_t blocksize = inode->i_sb->s_blocksize;
1945 unsigned long this_bio_flag = 0;
1946
1947 set_page_extent_mapped(page);
1948
1949 if (!PageUptodate(page)) {
1950 if (cleancache_get_page(page) == 0) {
1951 BUG_ON(blocksize != PAGE_SIZE);
1952 goto out;
1953 }
1954 }
1955
1956 end = page_end;
1957 while (1) {
1958 lock_extent(tree, start, end, GFP_NOFS);
1959 ordered = btrfs_lookup_ordered_extent(inode, start);
1960 if (!ordered)
1961 break;
1962 unlock_extent(tree, start, end, GFP_NOFS);
1963 btrfs_start_ordered_extent(inode, ordered, 1);
1964 btrfs_put_ordered_extent(ordered);
1965 }
1966
1967 if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
1968 char *userpage;
1969 size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
1970
1971 if (zero_offset) {
1972 iosize = PAGE_CACHE_SIZE - zero_offset;
1973 userpage = kmap_atomic(page, KM_USER0);
1974 memset(userpage + zero_offset, 0, iosize);
1975 flush_dcache_page(page);
1976 kunmap_atomic(userpage, KM_USER0);
1977 }
1978 }
1979 while (cur <= end) {
1980 if (cur >= last_byte) {
1981 char *userpage;
1982 struct extent_state *cached = NULL;
1983
1984 iosize = PAGE_CACHE_SIZE - pg_offset;
1985 userpage = kmap_atomic(page, KM_USER0);
1986 memset(userpage + pg_offset, 0, iosize);
1987 flush_dcache_page(page);
1988 kunmap_atomic(userpage, KM_USER0);
1989 set_extent_uptodate(tree, cur, cur + iosize - 1,
1990 &cached, GFP_NOFS);
1991 unlock_extent_cached(tree, cur, cur + iosize - 1,
1992 &cached, GFP_NOFS);
1993 break;
1994 }
1995 em = get_extent(inode, page, pg_offset, cur,
1996 end - cur + 1, 0);
1997 if (IS_ERR_OR_NULL(em)) {
1998 SetPageError(page);
1999 unlock_extent(tree, cur, end, GFP_NOFS);
2000 break;
2001 }
2002 extent_offset = cur - em->start;
2003 BUG_ON(extent_map_end(em) <= cur);
2004 BUG_ON(end < cur);
2005
2006 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2007 this_bio_flag = EXTENT_BIO_COMPRESSED;
2008 extent_set_compress_type(&this_bio_flag,
2009 em->compress_type);
2010 }
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 struct extent_state *cached = NULL;
2033
2034 userpage = kmap_atomic(page, KM_USER0);
2035 memset(userpage + pg_offset, 0, iosize);
2036 flush_dcache_page(page);
2037 kunmap_atomic(userpage, KM_USER0);
2038
2039 set_extent_uptodate(tree, cur, cur + iosize - 1,
2040 &cached, GFP_NOFS);
2041 unlock_extent_cached(tree, cur, cur + iosize - 1,
2042 &cached, GFP_NOFS);
2043 cur = cur + iosize;
2044 pg_offset += iosize;
2045 continue;
2046 }
2047 /* the get_extent function already copied into the page */
2048 if (test_range_bit(tree, cur, cur_end,
2049 EXTENT_UPTODATE, 1, NULL)) {
2050 check_page_uptodate(tree, page);
2051 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2052 cur = cur + iosize;
2053 pg_offset += iosize;
2054 continue;
2055 }
2056 /* we have an inline extent but it didn't get marked up
2057 * to date. Error out
2058 */
2059 if (block_start == EXTENT_MAP_INLINE) {
2060 SetPageError(page);
2061 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2062 cur = cur + iosize;
2063 pg_offset += iosize;
2064 continue;
2065 }
2066
2067 ret = 0;
2068 if (tree->ops && tree->ops->readpage_io_hook) {
2069 ret = tree->ops->readpage_io_hook(page, cur,
2070 cur + iosize - 1);
2071 }
2072 if (!ret) {
2073 unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
2074 pnr -= page->index;
2075 ret = submit_extent_page(READ, tree, page,
2076 sector, disk_io_size, pg_offset,
2077 bdev, bio, pnr,
2078 end_bio_extent_readpage, mirror_num,
2079 *bio_flags,
2080 this_bio_flag);
2081 nr++;
2082 *bio_flags = this_bio_flag;
2083 }
2084 if (ret)
2085 SetPageError(page);
2086 cur = cur + iosize;
2087 pg_offset += iosize;
2088 }
2089 out:
2090 if (!nr) {
2091 if (!PageError(page))
2092 SetPageUptodate(page);
2093 unlock_page(page);
2094 }
2095 return 0;
2096 }
2097
2098 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
2099 get_extent_t *get_extent)
2100 {
2101 struct bio *bio = NULL;
2102 unsigned long bio_flags = 0;
2103 int ret;
2104
2105 ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
2106 &bio_flags);
2107 if (bio)
2108 ret = submit_one_bio(READ, bio, 0, bio_flags);
2109 return ret;
2110 }
2111
2112 static noinline void update_nr_written(struct page *page,
2113 struct writeback_control *wbc,
2114 unsigned long nr_written)
2115 {
2116 wbc->nr_to_write -= nr_written;
2117 if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
2118 wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
2119 page->mapping->writeback_index = page->index + nr_written;
2120 }
2121
2122 /*
2123 * the writepage semantics are similar to regular writepage. extent
2124 * records are inserted to lock ranges in the tree, and as dirty areas
2125 * are found, they are marked writeback. Then the lock bits are removed
2126 * and the end_io handler clears the writeback ranges
2127 */
2128 static int __extent_writepage(struct page *page, struct writeback_control *wbc,
2129 void *data)
2130 {
2131 struct inode *inode = page->mapping->host;
2132 struct extent_page_data *epd = data;
2133 struct extent_io_tree *tree = epd->tree;
2134 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2135 u64 delalloc_start;
2136 u64 page_end = start + PAGE_CACHE_SIZE - 1;
2137 u64 end;
2138 u64 cur = start;
2139 u64 extent_offset;
2140 u64 last_byte = i_size_read(inode);
2141 u64 block_start;
2142 u64 iosize;
2143 sector_t sector;
2144 struct extent_state *cached_state = NULL;
2145 struct extent_map *em;
2146 struct block_device *bdev;
2147 int ret;
2148 int nr = 0;
2149 size_t pg_offset = 0;
2150 size_t blocksize;
2151 loff_t i_size = i_size_read(inode);
2152 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2153 u64 nr_delalloc;
2154 u64 delalloc_end;
2155 int page_started;
2156 int compressed;
2157 int write_flags;
2158 unsigned long nr_written = 0;
2159
2160 if (wbc->sync_mode == WB_SYNC_ALL)
2161 write_flags = WRITE_SYNC;
2162 else
2163 write_flags = WRITE;
2164
2165 trace___extent_writepage(page, inode, wbc);
2166
2167 WARN_ON(!PageLocked(page));
2168 pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2169 if (page->index > end_index ||
2170 (page->index == end_index && !pg_offset)) {
2171 page->mapping->a_ops->invalidatepage(page, 0);
2172 unlock_page(page);
2173 return 0;
2174 }
2175
2176 if (page->index == end_index) {
2177 char *userpage;
2178
2179 userpage = kmap_atomic(page, KM_USER0);
2180 memset(userpage + pg_offset, 0,
2181 PAGE_CACHE_SIZE - pg_offset);
2182 kunmap_atomic(userpage, KM_USER0);
2183 flush_dcache_page(page);
2184 }
2185 pg_offset = 0;
2186
2187 set_page_extent_mapped(page);
2188
2189 delalloc_start = start;
2190 delalloc_end = 0;
2191 page_started = 0;
2192 if (!epd->extent_locked) {
2193 u64 delalloc_to_write = 0;
2194 /*
2195 * make sure the wbc mapping index is at least updated
2196 * to this page.
2197 */
2198 update_nr_written(page, wbc, 0);
2199
2200 while (delalloc_end < page_end) {
2201 nr_delalloc = find_lock_delalloc_range(inode, tree,
2202 page,
2203 &delalloc_start,
2204 &delalloc_end,
2205 128 * 1024 * 1024);
2206 if (nr_delalloc == 0) {
2207 delalloc_start = delalloc_end + 1;
2208 continue;
2209 }
2210 tree->ops->fill_delalloc(inode, page, delalloc_start,
2211 delalloc_end, &page_started,
2212 &nr_written);
2213 /*
2214 * delalloc_end is already one less than the total
2215 * length, so we don't subtract one from
2216 * PAGE_CACHE_SIZE
2217 */
2218 delalloc_to_write += (delalloc_end - delalloc_start +
2219 PAGE_CACHE_SIZE) >>
2220 PAGE_CACHE_SHIFT;
2221 delalloc_start = delalloc_end + 1;
2222 }
2223 if (wbc->nr_to_write < delalloc_to_write) {
2224 int thresh = 8192;
2225
2226 if (delalloc_to_write < thresh * 2)
2227 thresh = delalloc_to_write;
2228 wbc->nr_to_write = min_t(u64, delalloc_to_write,
2229 thresh);
2230 }
2231
2232 /* did the fill delalloc function already unlock and start
2233 * the IO?
2234 */
2235 if (page_started) {
2236 ret = 0;
2237 /*
2238 * we've unlocked the page, so we can't update
2239 * the mapping's writeback index, just update
2240 * nr_to_write.
2241 */
2242 wbc->nr_to_write -= nr_written;
2243 goto done_unlocked;
2244 }
2245 }
2246 if (tree->ops && tree->ops->writepage_start_hook) {
2247 ret = tree->ops->writepage_start_hook(page, start,
2248 page_end);
2249 if (ret == -EAGAIN) {
2250 redirty_page_for_writepage(wbc, page);
2251 update_nr_written(page, wbc, nr_written);
2252 unlock_page(page);
2253 ret = 0;
2254 goto done_unlocked;
2255 }
2256 }
2257
2258 /*
2259 * we don't want to touch the inode after unlocking the page,
2260 * so we update the mapping writeback index now
2261 */
2262 update_nr_written(page, wbc, nr_written + 1);
2263
2264 end = page_end;
2265 if (last_byte <= start) {
2266 if (tree->ops && tree->ops->writepage_end_io_hook)
2267 tree->ops->writepage_end_io_hook(page, start,
2268 page_end, NULL, 1);
2269 goto done;
2270 }
2271
2272 blocksize = inode->i_sb->s_blocksize;
2273
2274 while (cur <= end) {
2275 if (cur >= last_byte) {
2276 if (tree->ops && tree->ops->writepage_end_io_hook)
2277 tree->ops->writepage_end_io_hook(page, cur,
2278 page_end, NULL, 1);
2279 break;
2280 }
2281 em = epd->get_extent(inode, page, pg_offset, cur,
2282 end - cur + 1, 1);
2283 if (IS_ERR_OR_NULL(em)) {
2284 SetPageError(page);
2285 break;
2286 }
2287
2288 extent_offset = cur - em->start;
2289 BUG_ON(extent_map_end(em) <= cur);
2290 BUG_ON(end < cur);
2291 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2292 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2293 sector = (em->block_start + extent_offset) >> 9;
2294 bdev = em->bdev;
2295 block_start = em->block_start;
2296 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2297 free_extent_map(em);
2298 em = NULL;
2299
2300 /*
2301 * compressed and inline extents are written through other
2302 * paths in the FS
2303 */
2304 if (compressed || block_start == EXTENT_MAP_HOLE ||
2305 block_start == EXTENT_MAP_INLINE) {
2306 /*
2307 * end_io notification does not happen here for
2308 * compressed extents
2309 */
2310 if (!compressed && tree->ops &&
2311 tree->ops->writepage_end_io_hook)
2312 tree->ops->writepage_end_io_hook(page, cur,
2313 cur + iosize - 1,
2314 NULL, 1);
2315 else if (compressed) {
2316 /* we don't want to end_page_writeback on
2317 * a compressed extent. this happens
2318 * elsewhere
2319 */
2320 nr++;
2321 }
2322
2323 cur += iosize;
2324 pg_offset += iosize;
2325 continue;
2326 }
2327 /* leave this out until we have a page_mkwrite call */
2328 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2329 EXTENT_DIRTY, 0, NULL)) {
2330 cur = cur + iosize;
2331 pg_offset += iosize;
2332 continue;
2333 }
2334
2335 if (tree->ops && tree->ops->writepage_io_hook) {
2336 ret = tree->ops->writepage_io_hook(page, cur,
2337 cur + iosize - 1);
2338 } else {
2339 ret = 0;
2340 }
2341 if (ret) {
2342 SetPageError(page);
2343 } else {
2344 unsigned long max_nr = end_index + 1;
2345
2346 set_range_writeback(tree, cur, cur + iosize - 1);
2347 if (!PageWriteback(page)) {
2348 printk(KERN_ERR "btrfs warning page %lu not "
2349 "writeback, cur %llu end %llu\n",
2350 page->index, (unsigned long long)cur,
2351 (unsigned long long)end);
2352 }
2353
2354 ret = submit_extent_page(write_flags, tree, page,
2355 sector, iosize, pg_offset,
2356 bdev, &epd->bio, max_nr,
2357 end_bio_extent_writepage,
2358 0, 0, 0);
2359 if (ret)
2360 SetPageError(page);
2361 }
2362 cur = cur + iosize;
2363 pg_offset += iosize;
2364 nr++;
2365 }
2366 done:
2367 if (nr == 0) {
2368 /* make sure the mapping tag for page dirty gets cleared */
2369 set_page_writeback(page);
2370 end_page_writeback(page);
2371 }
2372 unlock_page(page);
2373
2374 done_unlocked:
2375
2376 /* drop our reference on any cached states */
2377 free_extent_state(cached_state);
2378 return 0;
2379 }
2380
2381 /**
2382 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
2383 * @mapping: address space structure to write
2384 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
2385 * @writepage: function called for each page
2386 * @data: data passed to writepage function
2387 *
2388 * If a page is already under I/O, write_cache_pages() skips it, even
2389 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
2390 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
2391 * and msync() need to guarantee that all the data which was dirty at the time
2392 * the call was made get new I/O started against them. If wbc->sync_mode is
2393 * WB_SYNC_ALL then we were called for data integrity and we must wait for
2394 * existing IO to complete.
2395 */
2396 static int extent_write_cache_pages(struct extent_io_tree *tree,
2397 struct address_space *mapping,
2398 struct writeback_control *wbc,
2399 writepage_t writepage, void *data,
2400 void (*flush_fn)(void *))
2401 {
2402 int ret = 0;
2403 int done = 0;
2404 int nr_to_write_done = 0;
2405 struct pagevec pvec;
2406 int nr_pages;
2407 pgoff_t index;
2408 pgoff_t end; /* Inclusive */
2409 int scanned = 0;
2410 int tag;
2411
2412 pagevec_init(&pvec, 0);
2413 if (wbc->range_cyclic) {
2414 index = mapping->writeback_index; /* Start from prev offset */
2415 end = -1;
2416 } else {
2417 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2418 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2419 scanned = 1;
2420 }
2421 if (wbc->sync_mode == WB_SYNC_ALL)
2422 tag = PAGECACHE_TAG_TOWRITE;
2423 else
2424 tag = PAGECACHE_TAG_DIRTY;
2425 retry:
2426 if (wbc->sync_mode == WB_SYNC_ALL)
2427 tag_pages_for_writeback(mapping, index, end);
2428 while (!done && !nr_to_write_done && (index <= end) &&
2429 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2430 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2431 unsigned i;
2432
2433 scanned = 1;
2434 for (i = 0; i < nr_pages; i++) {
2435 struct page *page = pvec.pages[i];
2436
2437 /*
2438 * At this point we hold neither mapping->tree_lock nor
2439 * lock on the page itself: the page may be truncated or
2440 * invalidated (changing page->mapping to NULL), or even
2441 * swizzled back from swapper_space to tmpfs file
2442 * mapping
2443 */
2444 if (tree->ops && tree->ops->write_cache_pages_lock_hook)
2445 tree->ops->write_cache_pages_lock_hook(page);
2446 else
2447 lock_page(page);
2448
2449 if (unlikely(page->mapping != mapping)) {
2450 unlock_page(page);
2451 continue;
2452 }
2453
2454 if (!wbc->range_cyclic && page->index > end) {
2455 done = 1;
2456 unlock_page(page);
2457 continue;
2458 }
2459
2460 if (wbc->sync_mode != WB_SYNC_NONE) {
2461 if (PageWriteback(page))
2462 flush_fn(data);
2463 wait_on_page_writeback(page);
2464 }
2465
2466 if (PageWriteback(page) ||
2467 !clear_page_dirty_for_io(page)) {
2468 unlock_page(page);
2469 continue;
2470 }
2471
2472 ret = (*writepage)(page, wbc, data);
2473
2474 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
2475 unlock_page(page);
2476 ret = 0;
2477 }
2478 if (ret)
2479 done = 1;
2480
2481 /*
2482 * the filesystem may choose to bump up nr_to_write.
2483 * We have to make sure to honor the new nr_to_write
2484 * at any time
2485 */
2486 nr_to_write_done = wbc->nr_to_write <= 0;
2487 }
2488 pagevec_release(&pvec);
2489 cond_resched();
2490 }
2491 if (!scanned && !done) {
2492 /*
2493 * We hit the last page and there is more work to be done: wrap
2494 * back to the start of the file
2495 */
2496 scanned = 1;
2497 index = 0;
2498 goto retry;
2499 }
2500 return ret;
2501 }
2502
2503 static void flush_epd_write_bio(struct extent_page_data *epd)
2504 {
2505 if (epd->bio) {
2506 if (epd->sync_io)
2507 submit_one_bio(WRITE_SYNC, epd->bio, 0, 0);
2508 else
2509 submit_one_bio(WRITE, epd->bio, 0, 0);
2510 epd->bio = NULL;
2511 }
2512 }
2513
2514 static noinline void flush_write_bio(void *data)
2515 {
2516 struct extent_page_data *epd = data;
2517 flush_epd_write_bio(epd);
2518 }
2519
2520 int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
2521 get_extent_t *get_extent,
2522 struct writeback_control *wbc)
2523 {
2524 int ret;
2525 struct address_space *mapping = page->mapping;
2526 struct extent_page_data epd = {
2527 .bio = NULL,
2528 .tree = tree,
2529 .get_extent = get_extent,
2530 .extent_locked = 0,
2531 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2532 };
2533 struct writeback_control wbc_writepages = {
2534 .sync_mode = wbc->sync_mode,
2535 .older_than_this = NULL,
2536 .nr_to_write = 64,
2537 .range_start = page_offset(page) + PAGE_CACHE_SIZE,
2538 .range_end = (loff_t)-1,
2539 };
2540
2541 ret = __extent_writepage(page, wbc, &epd);
2542
2543 extent_write_cache_pages(tree, mapping, &wbc_writepages,
2544 __extent_writepage, &epd, flush_write_bio);
2545 flush_epd_write_bio(&epd);
2546 return ret;
2547 }
2548
2549 int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
2550 u64 start, u64 end, get_extent_t *get_extent,
2551 int mode)
2552 {
2553 int ret = 0;
2554 struct address_space *mapping = inode->i_mapping;
2555 struct page *page;
2556 unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
2557 PAGE_CACHE_SHIFT;
2558
2559 struct extent_page_data epd = {
2560 .bio = NULL,
2561 .tree = tree,
2562 .get_extent = get_extent,
2563 .extent_locked = 1,
2564 .sync_io = mode == WB_SYNC_ALL,
2565 };
2566 struct writeback_control wbc_writepages = {
2567 .sync_mode = mode,
2568 .older_than_this = NULL,
2569 .nr_to_write = nr_pages * 2,
2570 .range_start = start,
2571 .range_end = end + 1,
2572 };
2573
2574 while (start <= end) {
2575 page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
2576 if (clear_page_dirty_for_io(page))
2577 ret = __extent_writepage(page, &wbc_writepages, &epd);
2578 else {
2579 if (tree->ops && tree->ops->writepage_end_io_hook)
2580 tree->ops->writepage_end_io_hook(page, start,
2581 start + PAGE_CACHE_SIZE - 1,
2582 NULL, 1);
2583 unlock_page(page);
2584 }
2585 page_cache_release(page);
2586 start += PAGE_CACHE_SIZE;
2587 }
2588
2589 flush_epd_write_bio(&epd);
2590 return ret;
2591 }
2592
2593 int extent_writepages(struct extent_io_tree *tree,
2594 struct address_space *mapping,
2595 get_extent_t *get_extent,
2596 struct writeback_control *wbc)
2597 {
2598 int ret = 0;
2599 struct extent_page_data epd = {
2600 .bio = NULL,
2601 .tree = tree,
2602 .get_extent = get_extent,
2603 .extent_locked = 0,
2604 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2605 };
2606
2607 ret = extent_write_cache_pages(tree, mapping, wbc,
2608 __extent_writepage, &epd,
2609 flush_write_bio);
2610 flush_epd_write_bio(&epd);
2611 return ret;
2612 }
2613
2614 int extent_readpages(struct extent_io_tree *tree,
2615 struct address_space *mapping,
2616 struct list_head *pages, unsigned nr_pages,
2617 get_extent_t get_extent)
2618 {
2619 struct bio *bio = NULL;
2620 unsigned page_idx;
2621 unsigned long bio_flags = 0;
2622
2623 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
2624 struct page *page = list_entry(pages->prev, struct page, lru);
2625
2626 prefetchw(&page->flags);
2627 list_del(&page->lru);
2628 if (!add_to_page_cache_lru(page, mapping,
2629 page->index, GFP_NOFS)) {
2630 __extent_read_full_page(tree, page, get_extent,
2631 &bio, 0, &bio_flags);
2632 }
2633 page_cache_release(page);
2634 }
2635 BUG_ON(!list_empty(pages));
2636 if (bio)
2637 submit_one_bio(READ, bio, 0, bio_flags);
2638 return 0;
2639 }
2640
2641 /*
2642 * basic invalidatepage code, this waits on any locked or writeback
2643 * ranges corresponding to the page, and then deletes any extent state
2644 * records from the tree
2645 */
2646 int extent_invalidatepage(struct extent_io_tree *tree,
2647 struct page *page, unsigned long offset)
2648 {
2649 struct extent_state *cached_state = NULL;
2650 u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
2651 u64 end = start + PAGE_CACHE_SIZE - 1;
2652 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
2653
2654 start += (offset + blocksize - 1) & ~(blocksize - 1);
2655 if (start > end)
2656 return 0;
2657
2658 lock_extent_bits(tree, start, end, 0, &cached_state, GFP_NOFS);
2659 wait_on_page_writeback(page);
2660 clear_extent_bit(tree, start, end,
2661 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
2662 EXTENT_DO_ACCOUNTING,
2663 1, 1, &cached_state, GFP_NOFS);
2664 return 0;
2665 }
2666
2667 /*
2668 * a helper for releasepage, this tests for areas of the page that
2669 * are locked or under IO and drops the related state bits if it is safe
2670 * to drop the page.
2671 */
2672 int try_release_extent_state(struct extent_map_tree *map,
2673 struct extent_io_tree *tree, struct page *page,
2674 gfp_t mask)
2675 {
2676 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2677 u64 end = start + PAGE_CACHE_SIZE - 1;
2678 int ret = 1;
2679
2680 if (test_range_bit(tree, start, end,
2681 EXTENT_IOBITS, 0, NULL))
2682 ret = 0;
2683 else {
2684 if ((mask & GFP_NOFS) == GFP_NOFS)
2685 mask = GFP_NOFS;
2686 /*
2687 * at this point we can safely clear everything except the
2688 * locked bit and the nodatasum bit
2689 */
2690 ret = clear_extent_bit(tree, start, end,
2691 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
2692 0, 0, NULL, mask);
2693
2694 /* if clear_extent_bit failed for enomem reasons,
2695 * we can't allow the release to continue.
2696 */
2697 if (ret < 0)
2698 ret = 0;
2699 else
2700 ret = 1;
2701 }
2702 return ret;
2703 }
2704
2705 /*
2706 * a helper for releasepage. As long as there are no locked extents
2707 * in the range corresponding to the page, both state records and extent
2708 * map records are removed
2709 */
2710 int try_release_extent_mapping(struct extent_map_tree *map,
2711 struct extent_io_tree *tree, struct page *page,
2712 gfp_t mask)
2713 {
2714 struct extent_map *em;
2715 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2716 u64 end = start + PAGE_CACHE_SIZE - 1;
2717
2718 if ((mask & __GFP_WAIT) &&
2719 page->mapping->host->i_size > 16 * 1024 * 1024) {
2720 u64 len;
2721 while (start <= end) {
2722 len = end - start + 1;
2723 write_lock(&map->lock);
2724 em = lookup_extent_mapping(map, start, len);
2725 if (IS_ERR_OR_NULL(em)) {
2726 write_unlock(&map->lock);
2727 break;
2728 }
2729 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
2730 em->start != start) {
2731 write_unlock(&map->lock);
2732 free_extent_map(em);
2733 break;
2734 }
2735 if (!test_range_bit(tree, em->start,
2736 extent_map_end(em) - 1,
2737 EXTENT_LOCKED | EXTENT_WRITEBACK,
2738 0, NULL)) {
2739 remove_extent_mapping(map, em);
2740 /* once for the rb tree */
2741 free_extent_map(em);
2742 }
2743 start = extent_map_end(em);
2744 write_unlock(&map->lock);
2745
2746 /* once for us */
2747 free_extent_map(em);
2748 }
2749 }
2750 return try_release_extent_state(map, tree, page, mask);
2751 }
2752
2753 /*
2754 * helper function for fiemap, which doesn't want to see any holes.
2755 * This maps until we find something past 'last'
2756 */
2757 static struct extent_map *get_extent_skip_holes(struct inode *inode,
2758 u64 offset,
2759 u64 last,
2760 get_extent_t *get_extent)
2761 {
2762 u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
2763 struct extent_map *em;
2764 u64 len;
2765
2766 if (offset >= last)
2767 return NULL;
2768
2769 while(1) {
2770 len = last - offset;
2771 if (len == 0)
2772 break;
2773 len = (len + sectorsize - 1) & ~(sectorsize - 1);
2774 em = get_extent(inode, NULL, 0, offset, len, 0);
2775 if (IS_ERR_OR_NULL(em))
2776 return em;
2777
2778 /* if this isn't a hole return it */
2779 if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
2780 em->block_start != EXTENT_MAP_HOLE) {
2781 return em;
2782 }
2783
2784 /* this is a hole, advance to the next extent */
2785 offset = extent_map_end(em);
2786 free_extent_map(em);
2787 if (offset >= last)
2788 break;
2789 }
2790 return NULL;
2791 }
2792
2793 int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
2794 __u64 start, __u64 len, get_extent_t *get_extent)
2795 {
2796 int ret = 0;
2797 u64 off = start;
2798 u64 max = start + len;
2799 u32 flags = 0;
2800 u32 found_type;
2801 u64 last;
2802 u64 last_for_get_extent = 0;
2803 u64 disko = 0;
2804 u64 isize = i_size_read(inode);
2805 struct btrfs_key found_key;
2806 struct extent_map *em = NULL;
2807 struct extent_state *cached_state = NULL;
2808 struct btrfs_path *path;
2809 struct btrfs_file_extent_item *item;
2810 int end = 0;
2811 u64 em_start = 0;
2812 u64 em_len = 0;
2813 u64 em_end = 0;
2814 unsigned long emflags;
2815
2816 if (len == 0)
2817 return -EINVAL;
2818
2819 path = btrfs_alloc_path();
2820 if (!path)
2821 return -ENOMEM;
2822 path->leave_spinning = 1;
2823
2824 /*
2825 * lookup the last file extent. We're not using i_size here
2826 * because there might be preallocation past i_size
2827 */
2828 ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
2829 path, btrfs_ino(inode), -1, 0);
2830 if (ret < 0) {
2831 btrfs_free_path(path);
2832 return ret;
2833 }
2834 WARN_ON(!ret);
2835 path->slots[0]--;
2836 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2837 struct btrfs_file_extent_item);
2838 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
2839 found_type = btrfs_key_type(&found_key);
2840
2841 /* No extents, but there might be delalloc bits */
2842 if (found_key.objectid != btrfs_ino(inode) ||
2843 found_type != BTRFS_EXTENT_DATA_KEY) {
2844 /* have to trust i_size as the end */
2845 last = (u64)-1;
2846 last_for_get_extent = isize;
2847 } else {
2848 /*
2849 * remember the start of the last extent. There are a
2850 * bunch of different factors that go into the length of the
2851 * extent, so its much less complex to remember where it started
2852 */
2853 last = found_key.offset;
2854 last_for_get_extent = last + 1;
2855 }
2856 btrfs_free_path(path);
2857
2858 /*
2859 * we might have some extents allocated but more delalloc past those
2860 * extents. so, we trust isize unless the start of the last extent is
2861 * beyond isize
2862 */
2863 if (last < isize) {
2864 last = (u64)-1;
2865 last_for_get_extent = isize;
2866 }
2867
2868 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
2869 &cached_state, GFP_NOFS);
2870
2871 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2872 get_extent);
2873 if (!em)
2874 goto out;
2875 if (IS_ERR(em)) {
2876 ret = PTR_ERR(em);
2877 goto out;
2878 }
2879
2880 while (!end) {
2881 u64 offset_in_extent;
2882
2883 /* break if the extent we found is outside the range */
2884 if (em->start >= max || extent_map_end(em) < off)
2885 break;
2886
2887 /*
2888 * get_extent may return an extent that starts before our
2889 * requested range. We have to make sure the ranges
2890 * we return to fiemap always move forward and don't
2891 * overlap, so adjust the offsets here
2892 */
2893 em_start = max(em->start, off);
2894
2895 /*
2896 * record the offset from the start of the extent
2897 * for adjusting the disk offset below
2898 */
2899 offset_in_extent = em_start - em->start;
2900 em_end = extent_map_end(em);
2901 em_len = em_end - em_start;
2902 emflags = em->flags;
2903 disko = 0;
2904 flags = 0;
2905
2906 /*
2907 * bump off for our next call to get_extent
2908 */
2909 off = extent_map_end(em);
2910 if (off >= max)
2911 end = 1;
2912
2913 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
2914 end = 1;
2915 flags |= FIEMAP_EXTENT_LAST;
2916 } else if (em->block_start == EXTENT_MAP_INLINE) {
2917 flags |= (FIEMAP_EXTENT_DATA_INLINE |
2918 FIEMAP_EXTENT_NOT_ALIGNED);
2919 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
2920 flags |= (FIEMAP_EXTENT_DELALLOC |
2921 FIEMAP_EXTENT_UNKNOWN);
2922 } else {
2923 disko = em->block_start + offset_in_extent;
2924 }
2925 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
2926 flags |= FIEMAP_EXTENT_ENCODED;
2927
2928 free_extent_map(em);
2929 em = NULL;
2930 if ((em_start >= last) || em_len == (u64)-1 ||
2931 (last == (u64)-1 && isize <= em_end)) {
2932 flags |= FIEMAP_EXTENT_LAST;
2933 end = 1;
2934 }
2935
2936 /* now scan forward to see if this is really the last extent. */
2937 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2938 get_extent);
2939 if (IS_ERR(em)) {
2940 ret = PTR_ERR(em);
2941 goto out;
2942 }
2943 if (!em) {
2944 flags |= FIEMAP_EXTENT_LAST;
2945 end = 1;
2946 }
2947 ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
2948 em_len, flags);
2949 if (ret)
2950 goto out_free;
2951 }
2952 out_free:
2953 free_extent_map(em);
2954 out:
2955 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len,
2956 &cached_state, GFP_NOFS);
2957 return ret;
2958 }
2959
2960 static inline struct page *extent_buffer_page(struct extent_buffer *eb,
2961 unsigned long i)
2962 {
2963 struct page *p;
2964 struct address_space *mapping;
2965
2966 if (i == 0)
2967 return eb->first_page;
2968 i += eb->start >> PAGE_CACHE_SHIFT;
2969 mapping = eb->first_page->mapping;
2970 if (!mapping)
2971 return NULL;
2972
2973 /*
2974 * extent_buffer_page is only called after pinning the page
2975 * by increasing the reference count. So we know the page must
2976 * be in the radix tree.
2977 */
2978 rcu_read_lock();
2979 p = radix_tree_lookup(&mapping->page_tree, i);
2980 rcu_read_unlock();
2981
2982 return p;
2983 }
2984
2985 static inline unsigned long num_extent_pages(u64 start, u64 len)
2986 {
2987 return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
2988 (start >> PAGE_CACHE_SHIFT);
2989 }
2990
2991 static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
2992 u64 start,
2993 unsigned long len,
2994 gfp_t mask)
2995 {
2996 struct extent_buffer *eb = NULL;
2997 #if LEAK_DEBUG
2998 unsigned long flags;
2999 #endif
3000
3001 eb = kmem_cache_zalloc(extent_buffer_cache, mask);
3002 if (eb == NULL)
3003 return NULL;
3004 eb->start = start;
3005 eb->len = len;
3006 rwlock_init(&eb->lock);
3007 atomic_set(&eb->write_locks, 0);
3008 atomic_set(&eb->read_locks, 0);
3009 atomic_set(&eb->blocking_readers, 0);
3010 atomic_set(&eb->blocking_writers, 0);
3011 atomic_set(&eb->spinning_readers, 0);
3012 atomic_set(&eb->spinning_writers, 0);
3013 init_waitqueue_head(&eb->write_lock_wq);
3014 init_waitqueue_head(&eb->read_lock_wq);
3015
3016 #if LEAK_DEBUG
3017 spin_lock_irqsave(&leak_lock, flags);
3018 list_add(&eb->leak_list, &buffers);
3019 spin_unlock_irqrestore(&leak_lock, flags);
3020 #endif
3021 atomic_set(&eb->refs, 1);
3022
3023 return eb;
3024 }
3025
3026 static void __free_extent_buffer(struct extent_buffer *eb)
3027 {
3028 #if LEAK_DEBUG
3029 unsigned long flags;
3030 spin_lock_irqsave(&leak_lock, flags);
3031 list_del(&eb->leak_list);
3032 spin_unlock_irqrestore(&leak_lock, flags);
3033 #endif
3034 kmem_cache_free(extent_buffer_cache, eb);
3035 }
3036
3037 /*
3038 * Helper for releasing extent buffer page.
3039 */
3040 static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
3041 unsigned long start_idx)
3042 {
3043 unsigned long index;
3044 struct page *page;
3045
3046 if (!eb->first_page)
3047 return;
3048
3049 index = num_extent_pages(eb->start, eb->len);
3050 if (start_idx >= index)
3051 return;
3052
3053 do {
3054 index--;
3055 page = extent_buffer_page(eb, index);
3056 if (page)
3057 page_cache_release(page);
3058 } while (index != start_idx);
3059 }
3060
3061 /*
3062 * Helper for releasing the extent buffer.
3063 */
3064 static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
3065 {
3066 btrfs_release_extent_buffer_page(eb, 0);
3067 __free_extent_buffer(eb);
3068 }
3069
3070 struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
3071 u64 start, unsigned long len,
3072 struct page *page0)
3073 {
3074 unsigned long num_pages = num_extent_pages(start, len);
3075 unsigned long i;
3076 unsigned long index = start >> PAGE_CACHE_SHIFT;
3077 struct extent_buffer *eb;
3078 struct extent_buffer *exists = NULL;
3079 struct page *p;
3080 struct address_space *mapping = tree->mapping;
3081 int uptodate = 1;
3082 int ret;
3083
3084 rcu_read_lock();
3085 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3086 if (eb && atomic_inc_not_zero(&eb->refs)) {
3087 rcu_read_unlock();
3088 mark_page_accessed(eb->first_page);
3089 return eb;
3090 }
3091 rcu_read_unlock();
3092
3093 eb = __alloc_extent_buffer(tree, start, len, GFP_NOFS);
3094 if (!eb)
3095 return NULL;
3096
3097 if (page0) {
3098 eb->first_page = page0;
3099 i = 1;
3100 index++;
3101 page_cache_get(page0);
3102 mark_page_accessed(page0);
3103 set_page_extent_mapped(page0);
3104 set_page_extent_head(page0, len);
3105 uptodate = PageUptodate(page0);
3106 } else {
3107 i = 0;
3108 }
3109 for (; i < num_pages; i++, index++) {
3110 p = find_or_create_page(mapping, index, GFP_NOFS);
3111 if (!p) {
3112 WARN_ON(1);
3113 goto free_eb;
3114 }
3115 set_page_extent_mapped(p);
3116 mark_page_accessed(p);
3117 if (i == 0) {
3118 eb->first_page = p;
3119 set_page_extent_head(p, len);
3120 } else {
3121 set_page_private(p, EXTENT_PAGE_PRIVATE);
3122 }
3123 if (!PageUptodate(p))
3124 uptodate = 0;
3125
3126 /*
3127 * see below about how we avoid a nasty race with release page
3128 * and why we unlock later
3129 */
3130 if (i != 0)
3131 unlock_page(p);
3132 }
3133 if (uptodate)
3134 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3135
3136 ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
3137 if (ret)
3138 goto free_eb;
3139
3140 spin_lock(&tree->buffer_lock);
3141 ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
3142 if (ret == -EEXIST) {
3143 exists = radix_tree_lookup(&tree->buffer,
3144 start >> PAGE_CACHE_SHIFT);
3145 /* add one reference for the caller */
3146 atomic_inc(&exists->refs);
3147 spin_unlock(&tree->buffer_lock);
3148 radix_tree_preload_end();
3149 goto free_eb;
3150 }
3151 /* add one reference for the tree */
3152 atomic_inc(&eb->refs);
3153 spin_unlock(&tree->buffer_lock);
3154 radix_tree_preload_end();
3155
3156 /*
3157 * there is a race where release page may have
3158 * tried to find this extent buffer in the radix
3159 * but failed. It will tell the VM it is safe to
3160 * reclaim the, and it will clear the page private bit.
3161 * We must make sure to set the page private bit properly
3162 * after the extent buffer is in the radix tree so
3163 * it doesn't get lost
3164 */
3165 set_page_extent_mapped(eb->first_page);
3166 set_page_extent_head(eb->first_page, eb->len);
3167 if (!page0)
3168 unlock_page(eb->first_page);
3169 return eb;
3170
3171 free_eb:
3172 if (eb->first_page && !page0)
3173 unlock_page(eb->first_page);
3174
3175 if (!atomic_dec_and_test(&eb->refs))
3176 return exists;
3177 btrfs_release_extent_buffer(eb);
3178 return exists;
3179 }
3180
3181 struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
3182 u64 start, unsigned long len)
3183 {
3184 struct extent_buffer *eb;
3185
3186 rcu_read_lock();
3187 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3188 if (eb && atomic_inc_not_zero(&eb->refs)) {
3189 rcu_read_unlock();
3190 mark_page_accessed(eb->first_page);
3191 return eb;
3192 }
3193 rcu_read_unlock();
3194
3195 return NULL;
3196 }
3197
3198 void free_extent_buffer(struct extent_buffer *eb)
3199 {
3200 if (!eb)
3201 return;
3202
3203 if (!atomic_dec_and_test(&eb->refs))
3204 return;
3205
3206 WARN_ON(1);
3207 }
3208
3209 int clear_extent_buffer_dirty(struct extent_io_tree *tree,
3210 struct extent_buffer *eb)
3211 {
3212 unsigned long i;
3213 unsigned long num_pages;
3214 struct page *page;
3215
3216 num_pages = num_extent_pages(eb->start, eb->len);
3217
3218 for (i = 0; i < num_pages; i++) {
3219 page = extent_buffer_page(eb, i);
3220 if (!PageDirty(page))
3221 continue;
3222
3223 lock_page(page);
3224 WARN_ON(!PagePrivate(page));
3225
3226 set_page_extent_mapped(page);
3227 if (i == 0)
3228 set_page_extent_head(page, eb->len);
3229
3230 clear_page_dirty_for_io(page);
3231 spin_lock_irq(&page->mapping->tree_lock);
3232 if (!PageDirty(page)) {
3233 radix_tree_tag_clear(&page->mapping->page_tree,
3234 page_index(page),
3235 PAGECACHE_TAG_DIRTY);
3236 }
3237 spin_unlock_irq(&page->mapping->tree_lock);
3238 unlock_page(page);
3239 }
3240 return 0;
3241 }
3242
3243 int set_extent_buffer_dirty(struct extent_io_tree *tree,
3244 struct extent_buffer *eb)
3245 {
3246 unsigned long i;
3247 unsigned long num_pages;
3248 int was_dirty = 0;
3249
3250 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
3251 num_pages = num_extent_pages(eb->start, eb->len);
3252 for (i = 0; i < num_pages; i++)
3253 __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3254 return was_dirty;
3255 }
3256
3257 static int __eb_straddles_pages(u64 start, u64 len)
3258 {
3259 if (len < PAGE_CACHE_SIZE)
3260 return 1;
3261 if (start & (PAGE_CACHE_SIZE - 1))
3262 return 1;
3263 if ((start + len) & (PAGE_CACHE_SIZE - 1))
3264 return 1;
3265 return 0;
3266 }
3267
3268 static int eb_straddles_pages(struct extent_buffer *eb)
3269 {
3270 return __eb_straddles_pages(eb->start, eb->len);
3271 }
3272
3273 int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3274 struct extent_buffer *eb,
3275 struct extent_state **cached_state)
3276 {
3277 unsigned long i;
3278 struct page *page;
3279 unsigned long num_pages;
3280
3281 num_pages = num_extent_pages(eb->start, eb->len);
3282 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3283
3284 if (eb_straddles_pages(eb)) {
3285 clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3286 cached_state, GFP_NOFS);
3287 }
3288 for (i = 0; i < num_pages; i++) {
3289 page = extent_buffer_page(eb, i);
3290 if (page)
3291 ClearPageUptodate(page);
3292 }
3293 return 0;
3294 }
3295
3296 int set_extent_buffer_uptodate(struct extent_io_tree *tree,
3297 struct extent_buffer *eb)
3298 {
3299 unsigned long i;
3300 struct page *page;
3301 unsigned long num_pages;
3302
3303 num_pages = num_extent_pages(eb->start, eb->len);
3304
3305 if (eb_straddles_pages(eb)) {
3306 set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3307 NULL, GFP_NOFS);
3308 }
3309 for (i = 0; i < num_pages; i++) {
3310 page = extent_buffer_page(eb, i);
3311 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3312 ((i == num_pages - 1) &&
3313 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3314 check_page_uptodate(tree, page);
3315 continue;
3316 }
3317 SetPageUptodate(page);
3318 }
3319 return 0;
3320 }
3321
3322 int extent_range_uptodate(struct extent_io_tree *tree,
3323 u64 start, u64 end)
3324 {
3325 struct page *page;
3326 int ret;
3327 int pg_uptodate = 1;
3328 int uptodate;
3329 unsigned long index;
3330
3331 if (__eb_straddles_pages(start, end - start + 1)) {
3332 ret = test_range_bit(tree, start, end,
3333 EXTENT_UPTODATE, 1, NULL);
3334 if (ret)
3335 return 1;
3336 }
3337 while (start <= end) {
3338 index = start >> PAGE_CACHE_SHIFT;
3339 page = find_get_page(tree->mapping, index);
3340 uptodate = PageUptodate(page);
3341 page_cache_release(page);
3342 if (!uptodate) {
3343 pg_uptodate = 0;
3344 break;
3345 }
3346 start += PAGE_CACHE_SIZE;
3347 }
3348 return pg_uptodate;
3349 }
3350
3351 int extent_buffer_uptodate(struct extent_io_tree *tree,
3352 struct extent_buffer *eb,
3353 struct extent_state *cached_state)
3354 {
3355 int ret = 0;
3356 unsigned long num_pages;
3357 unsigned long i;
3358 struct page *page;
3359 int pg_uptodate = 1;
3360
3361 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3362 return 1;
3363
3364 if (eb_straddles_pages(eb)) {
3365 ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3366 EXTENT_UPTODATE, 1, cached_state);
3367 if (ret)
3368 return ret;
3369 }
3370
3371 num_pages = num_extent_pages(eb->start, eb->len);
3372 for (i = 0; i < num_pages; i++) {
3373 page = extent_buffer_page(eb, i);
3374 if (!PageUptodate(page)) {
3375 pg_uptodate = 0;
3376 break;
3377 }
3378 }
3379 return pg_uptodate;
3380 }
3381
3382 int read_extent_buffer_pages(struct extent_io_tree *tree,
3383 struct extent_buffer *eb,
3384 u64 start, int wait,
3385 get_extent_t *get_extent, int mirror_num)
3386 {
3387 unsigned long i;
3388 unsigned long start_i;
3389 struct page *page;
3390 int err;
3391 int ret = 0;
3392 int locked_pages = 0;
3393 int all_uptodate = 1;
3394 int inc_all_pages = 0;
3395 unsigned long num_pages;
3396 struct bio *bio = NULL;
3397 unsigned long bio_flags = 0;
3398
3399 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3400 return 0;
3401
3402 if (eb_straddles_pages(eb)) {
3403 if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3404 EXTENT_UPTODATE, 1, NULL)) {
3405 return 0;
3406 }
3407 }
3408
3409 if (start) {
3410 WARN_ON(start < eb->start);
3411 start_i = (start >> PAGE_CACHE_SHIFT) -
3412 (eb->start >> PAGE_CACHE_SHIFT);
3413 } else {
3414 start_i = 0;
3415 }
3416
3417 num_pages = num_extent_pages(eb->start, eb->len);
3418 for (i = start_i; i < num_pages; i++) {
3419 page = extent_buffer_page(eb, i);
3420 if (!wait) {
3421 if (!trylock_page(page))
3422 goto unlock_exit;
3423 } else {
3424 lock_page(page);
3425 }
3426 locked_pages++;
3427 if (!PageUptodate(page))
3428 all_uptodate = 0;
3429 }
3430 if (all_uptodate) {
3431 if (start_i == 0)
3432 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3433 goto unlock_exit;
3434 }
3435
3436 for (i = start_i; i < num_pages; i++) {
3437 page = extent_buffer_page(eb, i);
3438
3439 WARN_ON(!PagePrivate(page));
3440
3441 set_page_extent_mapped(page);
3442 if (i == 0)
3443 set_page_extent_head(page, eb->len);
3444
3445 if (inc_all_pages)
3446 page_cache_get(page);
3447 if (!PageUptodate(page)) {
3448 if (start_i == 0)
3449 inc_all_pages = 1;
3450 ClearPageError(page);
3451 err = __extent_read_full_page(tree, page,
3452 get_extent, &bio,
3453 mirror_num, &bio_flags);
3454 if (err)
3455 ret = err;
3456 } else {
3457 unlock_page(page);
3458 }
3459 }
3460
3461 if (bio)
3462 submit_one_bio(READ, bio, mirror_num, bio_flags);
3463
3464 if (ret || !wait)
3465 return ret;
3466
3467 for (i = start_i; i < num_pages; i++) {
3468 page = extent_buffer_page(eb, i);
3469 wait_on_page_locked(page);
3470 if (!PageUptodate(page))
3471 ret = -EIO;
3472 }
3473
3474 if (!ret)
3475 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3476 return ret;
3477
3478 unlock_exit:
3479 i = start_i;
3480 while (locked_pages > 0) {
3481 page = extent_buffer_page(eb, i);
3482 i++;
3483 unlock_page(page);
3484 locked_pages--;
3485 }
3486 return ret;
3487 }
3488
3489 void read_extent_buffer(struct extent_buffer *eb, void *dstv,
3490 unsigned long start,
3491 unsigned long len)
3492 {
3493 size_t cur;
3494 size_t offset;
3495 struct page *page;
3496 char *kaddr;
3497 char *dst = (char *)dstv;
3498 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3499 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3500
3501 WARN_ON(start > eb->len);
3502 WARN_ON(start + len > eb->start + eb->len);
3503
3504 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3505
3506 while (len > 0) {
3507 page = extent_buffer_page(eb, i);
3508
3509 cur = min(len, (PAGE_CACHE_SIZE - offset));
3510 kaddr = page_address(page);
3511 memcpy(dst, kaddr + offset, cur);
3512
3513 dst += cur;
3514 len -= cur;
3515 offset = 0;
3516 i++;
3517 }
3518 }
3519
3520 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
3521 unsigned long min_len, char **map,
3522 unsigned long *map_start,
3523 unsigned long *map_len)
3524 {
3525 size_t offset = start & (PAGE_CACHE_SIZE - 1);
3526 char *kaddr;
3527 struct page *p;
3528 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3529 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3530 unsigned long end_i = (start_offset + start + min_len - 1) >>
3531 PAGE_CACHE_SHIFT;
3532
3533 if (i != end_i)
3534 return -EINVAL;
3535
3536 if (i == 0) {
3537 offset = start_offset;
3538 *map_start = 0;
3539 } else {
3540 offset = 0;
3541 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
3542 }
3543
3544 if (start + min_len > eb->len) {
3545 printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
3546 "wanted %lu %lu\n", (unsigned long long)eb->start,
3547 eb->len, start, min_len);
3548 WARN_ON(1);
3549 return -EINVAL;
3550 }
3551
3552 p = extent_buffer_page(eb, i);
3553 kaddr = page_address(p);
3554 *map = kaddr + offset;
3555 *map_len = PAGE_CACHE_SIZE - offset;
3556 return 0;
3557 }
3558
3559 int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
3560 unsigned long start,
3561 unsigned long len)
3562 {
3563 size_t cur;
3564 size_t offset;
3565 struct page *page;
3566 char *kaddr;
3567 char *ptr = (char *)ptrv;
3568 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3569 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3570 int ret = 0;
3571
3572 WARN_ON(start > eb->len);
3573 WARN_ON(start + len > eb->start + eb->len);
3574
3575 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3576
3577 while (len > 0) {
3578 page = extent_buffer_page(eb, i);
3579
3580 cur = min(len, (PAGE_CACHE_SIZE - offset));
3581
3582 kaddr = page_address(page);
3583 ret = memcmp(ptr, kaddr + offset, cur);
3584 if (ret)
3585 break;
3586
3587 ptr += cur;
3588 len -= cur;
3589 offset = 0;
3590 i++;
3591 }
3592 return ret;
3593 }
3594
3595 void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
3596 unsigned long start, unsigned long len)
3597 {
3598 size_t cur;
3599 size_t offset;
3600 struct page *page;
3601 char *kaddr;
3602 char *src = (char *)srcv;
3603 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3604 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3605
3606 WARN_ON(start > eb->len);
3607 WARN_ON(start + len > eb->start + eb->len);
3608
3609 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3610
3611 while (len > 0) {
3612 page = extent_buffer_page(eb, i);
3613 WARN_ON(!PageUptodate(page));
3614
3615 cur = min(len, PAGE_CACHE_SIZE - offset);
3616 kaddr = page_address(page);
3617 memcpy(kaddr + offset, src, cur);
3618
3619 src += cur;
3620 len -= cur;
3621 offset = 0;
3622 i++;
3623 }
3624 }
3625
3626 void memset_extent_buffer(struct extent_buffer *eb, char c,
3627 unsigned long start, unsigned long len)
3628 {
3629 size_t cur;
3630 size_t offset;
3631 struct page *page;
3632 char *kaddr;
3633 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3634 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3635
3636 WARN_ON(start > eb->len);
3637 WARN_ON(start + len > eb->start + eb->len);
3638
3639 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3640
3641 while (len > 0) {
3642 page = extent_buffer_page(eb, i);
3643 WARN_ON(!PageUptodate(page));
3644
3645 cur = min(len, PAGE_CACHE_SIZE - offset);
3646 kaddr = page_address(page);
3647 memset(kaddr + offset, c, cur);
3648
3649 len -= cur;
3650 offset = 0;
3651 i++;
3652 }
3653 }
3654
3655 void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
3656 unsigned long dst_offset, unsigned long src_offset,
3657 unsigned long len)
3658 {
3659 u64 dst_len = dst->len;
3660 size_t cur;
3661 size_t offset;
3662 struct page *page;
3663 char *kaddr;
3664 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3665 unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3666
3667 WARN_ON(src->len != dst_len);
3668
3669 offset = (start_offset + dst_offset) &
3670 ((unsigned long)PAGE_CACHE_SIZE - 1);
3671
3672 while (len > 0) {
3673 page = extent_buffer_page(dst, i);
3674 WARN_ON(!PageUptodate(page));
3675
3676 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
3677
3678 kaddr = page_address(page);
3679 read_extent_buffer(src, kaddr + offset, src_offset, cur);
3680
3681 src_offset += cur;
3682 len -= cur;
3683 offset = 0;
3684 i++;
3685 }
3686 }
3687
3688 static void move_pages(struct page *dst_page, struct page *src_page,
3689 unsigned long dst_off, unsigned long src_off,
3690 unsigned long len)
3691 {
3692 char *dst_kaddr = page_address(dst_page);
3693 if (dst_page == src_page) {
3694 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
3695 } else {
3696 char *src_kaddr = page_address(src_page);
3697 char *p = dst_kaddr + dst_off + len;
3698 char *s = src_kaddr + src_off + len;
3699
3700 while (len--)
3701 *--p = *--s;
3702 }
3703 }
3704
3705 static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
3706 {
3707 unsigned long distance = (src > dst) ? src - dst : dst - src;
3708 return distance < len;
3709 }
3710
3711 static void copy_pages(struct page *dst_page, struct page *src_page,
3712 unsigned long dst_off, unsigned long src_off,
3713 unsigned long len)
3714 {
3715 char *dst_kaddr = page_address(dst_page);
3716 char *src_kaddr;
3717
3718 if (dst_page != src_page) {
3719 src_kaddr = page_address(src_page);
3720 } else {
3721 src_kaddr = dst_kaddr;
3722 BUG_ON(areas_overlap(src_off, dst_off, len));
3723 }
3724
3725 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
3726 }
3727
3728 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3729 unsigned long src_offset, unsigned long len)
3730 {
3731 size_t cur;
3732 size_t dst_off_in_page;
3733 size_t src_off_in_page;
3734 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3735 unsigned long dst_i;
3736 unsigned long src_i;
3737
3738 if (src_offset + len > dst->len) {
3739 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3740 "len %lu dst len %lu\n", src_offset, len, dst->len);
3741 BUG_ON(1);
3742 }
3743 if (dst_offset + len > dst->len) {
3744 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3745 "len %lu dst len %lu\n", dst_offset, len, dst->len);
3746 BUG_ON(1);
3747 }
3748
3749 while (len > 0) {
3750 dst_off_in_page = (start_offset + dst_offset) &
3751 ((unsigned long)PAGE_CACHE_SIZE - 1);
3752 src_off_in_page = (start_offset + src_offset) &
3753 ((unsigned long)PAGE_CACHE_SIZE - 1);
3754
3755 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3756 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
3757
3758 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
3759 src_off_in_page));
3760 cur = min_t(unsigned long, cur,
3761 (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
3762
3763 copy_pages(extent_buffer_page(dst, dst_i),
3764 extent_buffer_page(dst, src_i),
3765 dst_off_in_page, src_off_in_page, cur);
3766
3767 src_offset += cur;
3768 dst_offset += cur;
3769 len -= cur;
3770 }
3771 }
3772
3773 void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3774 unsigned long src_offset, unsigned long len)
3775 {
3776 size_t cur;
3777 size_t dst_off_in_page;
3778 size_t src_off_in_page;
3779 unsigned long dst_end = dst_offset + len - 1;
3780 unsigned long src_end = src_offset + len - 1;
3781 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3782 unsigned long dst_i;
3783 unsigned long src_i;
3784
3785 if (src_offset + len > dst->len) {
3786 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3787 "len %lu len %lu\n", src_offset, len, dst->len);
3788 BUG_ON(1);
3789 }
3790 if (dst_offset + len > dst->len) {
3791 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3792 "len %lu len %lu\n", dst_offset, len, dst->len);
3793 BUG_ON(1);
3794 }
3795 if (!areas_overlap(src_offset, dst_offset, len)) {
3796 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
3797 return;
3798 }
3799 while (len > 0) {
3800 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
3801 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
3802
3803 dst_off_in_page = (start_offset + dst_end) &
3804 ((unsigned long)PAGE_CACHE_SIZE - 1);
3805 src_off_in_page = (start_offset + src_end) &
3806 ((unsigned long)PAGE_CACHE_SIZE - 1);
3807
3808 cur = min_t(unsigned long, len, src_off_in_page + 1);
3809 cur = min(cur, dst_off_in_page + 1);
3810 move_pages(extent_buffer_page(dst, dst_i),
3811 extent_buffer_page(dst, src_i),
3812 dst_off_in_page - cur + 1,
3813 src_off_in_page - cur + 1, cur);
3814
3815 dst_end -= cur;
3816 src_end -= cur;
3817 len -= cur;
3818 }
3819 }
3820
3821 static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
3822 {
3823 struct extent_buffer *eb =
3824 container_of(head, struct extent_buffer, rcu_head);
3825
3826 btrfs_release_extent_buffer(eb);
3827 }
3828
3829 int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
3830 {
3831 u64 start = page_offset(page);
3832 struct extent_buffer *eb;
3833 int ret = 1;
3834
3835 spin_lock(&tree->buffer_lock);
3836 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3837 if (!eb) {
3838 spin_unlock(&tree->buffer_lock);
3839 return ret;
3840 }
3841
3842 if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3843 ret = 0;
3844 goto out;
3845 }
3846
3847 /*
3848 * set @eb->refs to 0 if it is already 1, and then release the @eb.
3849 * Or go back.
3850 */
3851 if (atomic_cmpxchg(&eb->refs, 1, 0) != 1) {
3852 ret = 0;
3853 goto out;
3854 }
3855
3856 radix_tree_delete(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3857 out:
3858 spin_unlock(&tree->buffer_lock);
3859
3860 /* at this point we can safely release the extent buffer */
3861 if (atomic_read(&eb->refs) == 0)
3862 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
3863 return ret;
3864 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree