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ath9k: qinfo never be NULL in setuptxqueue
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / btrfs / extent_io.c
blob067b1747421bfd655b2d0ddbd228f195cca65553
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 int 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 0;
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 return 0;
292 }
293
294 static int set_state_cb(struct extent_io_tree *tree,
295 struct extent_state *state, int *bits)
296 {
297 if (tree->ops && tree->ops->set_bit_hook) {
298 return tree->ops->set_bit_hook(tree->mapping->host,
299 state, bits);
300 }
301
302 return 0;
303 }
304
305 static void clear_state_cb(struct extent_io_tree *tree,
306 struct extent_state *state, int *bits)
307 {
308 if (tree->ops && tree->ops->clear_bit_hook)
309 tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
310 }
311
312 /*
313 * insert an extent_state struct into the tree. 'bits' are set on the
314 * struct before it is inserted.
315 *
316 * This may return -EEXIST if the extent is already there, in which case the
317 * state struct is freed.
318 *
319 * The tree lock is not taken internally. This is a utility function and
320 * probably isn't what you want to call (see set/clear_extent_bit).
321 */
322 static int insert_state(struct extent_io_tree *tree,
323 struct extent_state *state, u64 start, u64 end,
324 int *bits)
325 {
326 struct rb_node *node;
327 int bits_to_set = *bits & ~EXTENT_CTLBITS;
328 int ret;
329
330 if (end < start) {
331 printk(KERN_ERR "btrfs end < start %llu %llu\n",
332 (unsigned long long)end,
333 (unsigned long long)start);
334 WARN_ON(1);
335 }
336 state->start = start;
337 state->end = end;
338 ret = set_state_cb(tree, state, bits);
339 if (ret)
340 return ret;
341
342 if (bits_to_set & EXTENT_DIRTY)
343 tree->dirty_bytes += end - start + 1;
344 state->state |= bits_to_set;
345 node = tree_insert(&tree->state, end, &state->rb_node);
346 if (node) {
347 struct extent_state *found;
348 found = rb_entry(node, struct extent_state, rb_node);
349 printk(KERN_ERR "btrfs found node %llu %llu on insert of "
350 "%llu %llu\n", (unsigned long long)found->start,
351 (unsigned long long)found->end,
352 (unsigned long long)start, (unsigned long long)end);
353 return -EEXIST;
354 }
355 state->tree = tree;
356 merge_state(tree, state);
357 return 0;
358 }
359
360 static int split_cb(struct extent_io_tree *tree, struct extent_state *orig,
361 u64 split)
362 {
363 if (tree->ops && tree->ops->split_extent_hook)
364 return tree->ops->split_extent_hook(tree->mapping->host,
365 orig, split);
366 return 0;
367 }
368
369 /*
370 * split a given extent state struct in two, inserting the preallocated
371 * struct 'prealloc' as the newly created second half. 'split' indicates an
372 * offset inside 'orig' where it should be split.
373 *
374 * Before calling,
375 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
376 * are two extent state structs in the tree:
377 * prealloc: [orig->start, split - 1]
378 * orig: [ split, orig->end ]
379 *
380 * The tree locks are not taken by this function. They need to be held
381 * by the caller.
382 */
383 static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
384 struct extent_state *prealloc, u64 split)
385 {
386 struct rb_node *node;
387
388 split_cb(tree, orig, split);
389
390 prealloc->start = orig->start;
391 prealloc->end = split - 1;
392 prealloc->state = orig->state;
393 orig->start = split;
394
395 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
396 if (node) {
397 free_extent_state(prealloc);
398 return -EEXIST;
399 }
400 prealloc->tree = tree;
401 return 0;
402 }
403
404 /*
405 * utility function to clear some bits in an extent state struct.
406 * it will optionally wake up any one waiting on this state (wake == 1), or
407 * forcibly remove the state from the tree (delete == 1).
408 *
409 * If no bits are set on the state struct after clearing things, the
410 * struct is freed and removed from the tree
411 */
412 static int clear_state_bit(struct extent_io_tree *tree,
413 struct extent_state *state,
414 int *bits, int wake)
415 {
416 int bits_to_clear = *bits & ~EXTENT_CTLBITS;
417 int ret = state->state & bits_to_clear;
418
419 if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
420 u64 range = state->end - state->start + 1;
421 WARN_ON(range > tree->dirty_bytes);
422 tree->dirty_bytes -= range;
423 }
424 clear_state_cb(tree, state, bits);
425 state->state &= ~bits_to_clear;
426 if (wake)
427 wake_up(&state->wq);
428 if (state->state == 0) {
429 if (state->tree) {
430 rb_erase(&state->rb_node, &tree->state);
431 state->tree = NULL;
432 free_extent_state(state);
433 } else {
434 WARN_ON(1);
435 }
436 } else {
437 merge_state(tree, state);
438 }
439 return ret;
440 }
441
442 static struct extent_state *
443 alloc_extent_state_atomic(struct extent_state *prealloc)
444 {
445 if (!prealloc)
446 prealloc = alloc_extent_state(GFP_ATOMIC);
447
448 return prealloc;
449 }
450
451 /*
452 * clear some bits on a range in the tree. This may require splitting
453 * or inserting elements in the tree, so the gfp mask is used to
454 * indicate which allocations or sleeping are allowed.
455 *
456 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
457 * the given range from the tree regardless of state (ie for truncate).
458 *
459 * the range [start, end] is inclusive.
460 *
461 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
462 * bits were already set, or zero if none of the bits were already set.
463 */
464 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
465 int bits, int wake, int delete,
466 struct extent_state **cached_state,
467 gfp_t mask)
468 {
469 struct extent_state *state;
470 struct extent_state *cached;
471 struct extent_state *prealloc = NULL;
472 struct rb_node *next_node;
473 struct rb_node *node;
474 u64 last_end;
475 int err;
476 int set = 0;
477 int clear = 0;
478
479 if (delete)
480 bits |= ~EXTENT_CTLBITS;
481 bits |= EXTENT_FIRST_DELALLOC;
482
483 if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
484 clear = 1;
485 again:
486 if (!prealloc && (mask & __GFP_WAIT)) {
487 prealloc = alloc_extent_state(mask);
488 if (!prealloc)
489 return -ENOMEM;
490 }
491
492 spin_lock(&tree->lock);
493 if (cached_state) {
494 cached = *cached_state;
495
496 if (clear) {
497 *cached_state = NULL;
498 cached_state = NULL;
499 }
500
501 if (cached && cached->tree && cached->start <= start &&
502 cached->end > start) {
503 if (clear)
504 atomic_dec(&cached->refs);
505 state = cached;
506 goto hit_next;
507 }
508 if (clear)
509 free_extent_state(cached);
510 }
511 /*
512 * this search will find the extents that end after
513 * our range starts
514 */
515 node = tree_search(tree, start);
516 if (!node)
517 goto out;
518 state = rb_entry(node, struct extent_state, rb_node);
519 hit_next:
520 if (state->start > end)
521 goto out;
522 WARN_ON(state->end < start);
523 last_end = state->end;
524
525 /*
526 * | ---- desired range ---- |
527 * | state | or
528 * | ------------- state -------------- |
529 *
530 * We need to split the extent we found, and may flip
531 * bits on second half.
532 *
533 * If the extent we found extends past our range, we
534 * just split and search again. It'll get split again
535 * the next time though.
536 *
537 * If the extent we found is inside our range, we clear
538 * the desired bit on it.
539 */
540
541 if (state->start < start) {
542 prealloc = alloc_extent_state_atomic(prealloc);
543 BUG_ON(!prealloc);
544 err = split_state(tree, state, prealloc, start);
545 BUG_ON(err == -EEXIST);
546 prealloc = NULL;
547 if (err)
548 goto out;
549 if (state->end <= end) {
550 set |= clear_state_bit(tree, state, &bits, wake);
551 if (last_end == (u64)-1)
552 goto out;
553 start = last_end + 1;
554 }
555 goto search_again;
556 }
557 /*
558 * | ---- desired range ---- |
559 * | state |
560 * We need to split the extent, and clear the bit
561 * on the first half
562 */
563 if (state->start <= end && state->end > end) {
564 prealloc = alloc_extent_state_atomic(prealloc);
565 BUG_ON(!prealloc);
566 err = split_state(tree, state, prealloc, end + 1);
567 BUG_ON(err == -EEXIST);
568 if (wake)
569 wake_up(&state->wq);
570
571 set |= clear_state_bit(tree, prealloc, &bits, wake);
572
573 prealloc = NULL;
574 goto out;
575 }
576
577 if (state->end < end && prealloc && !need_resched())
578 next_node = rb_next(&state->rb_node);
579 else
580 next_node = NULL;
581
582 set |= clear_state_bit(tree, state, &bits, wake);
583 if (last_end == (u64)-1)
584 goto out;
585 start = last_end + 1;
586 if (start <= end && next_node) {
587 state = rb_entry(next_node, struct extent_state,
588 rb_node);
589 if (state->start == start)
590 goto hit_next;
591 }
592 goto search_again;
593
594 out:
595 spin_unlock(&tree->lock);
596 if (prealloc)
597 free_extent_state(prealloc);
598
599 return set;
600
601 search_again:
602 if (start > end)
603 goto out;
604 spin_unlock(&tree->lock);
605 if (mask & __GFP_WAIT)
606 cond_resched();
607 goto again;
608 }
609
610 static int wait_on_state(struct extent_io_tree *tree,
611 struct extent_state *state)
612 __releases(tree->lock)
613 __acquires(tree->lock)
614 {
615 DEFINE_WAIT(wait);
616 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
617 spin_unlock(&tree->lock);
618 schedule();
619 spin_lock(&tree->lock);
620 finish_wait(&state->wq, &wait);
621 return 0;
622 }
623
624 /*
625 * waits for one or more bits to clear on a range in the state tree.
626 * The range [start, end] is inclusive.
627 * The tree lock is taken by this function
628 */
629 int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
630 {
631 struct extent_state *state;
632 struct rb_node *node;
633
634 spin_lock(&tree->lock);
635 again:
636 while (1) {
637 /*
638 * this search will find all the extents that end after
639 * our range starts
640 */
641 node = tree_search(tree, start);
642 if (!node)
643 break;
644
645 state = rb_entry(node, struct extent_state, rb_node);
646
647 if (state->start > end)
648 goto out;
649
650 if (state->state & bits) {
651 start = state->start;
652 atomic_inc(&state->refs);
653 wait_on_state(tree, state);
654 free_extent_state(state);
655 goto again;
656 }
657 start = state->end + 1;
658
659 if (start > end)
660 break;
661
662 if (need_resched()) {
663 spin_unlock(&tree->lock);
664 cond_resched();
665 spin_lock(&tree->lock);
666 }
667 }
668 out:
669 spin_unlock(&tree->lock);
670 return 0;
671 }
672
673 static int set_state_bits(struct extent_io_tree *tree,
674 struct extent_state *state,
675 int *bits)
676 {
677 int ret;
678 int bits_to_set = *bits & ~EXTENT_CTLBITS;
679
680 ret = set_state_cb(tree, state, bits);
681 if (ret)
682 return ret;
683 if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
684 u64 range = state->end - state->start + 1;
685 tree->dirty_bytes += range;
686 }
687 state->state |= bits_to_set;
688
689 return 0;
690 }
691
692 static void cache_state(struct extent_state *state,
693 struct extent_state **cached_ptr)
694 {
695 if (cached_ptr && !(*cached_ptr)) {
696 if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
697 *cached_ptr = state;
698 atomic_inc(&state->refs);
699 }
700 }
701 }
702
703 static void uncache_state(struct extent_state **cached_ptr)
704 {
705 if (cached_ptr && (*cached_ptr)) {
706 struct extent_state *state = *cached_ptr;
707 *cached_ptr = NULL;
708 free_extent_state(state);
709 }
710 }
711
712 /*
713 * set some bits on a range in the tree. This may require allocations or
714 * sleeping, so the gfp mask is used to indicate what is allowed.
715 *
716 * If any of the exclusive bits are set, this will fail with -EEXIST if some
717 * part of the range already has the desired bits set. The start of the
718 * existing range is returned in failed_start in this case.
719 *
720 * [start, end] is inclusive This takes the tree lock.
721 */
722
723 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
724 int bits, int exclusive_bits, u64 *failed_start,
725 struct extent_state **cached_state, gfp_t mask)
726 {
727 struct extent_state *state;
728 struct extent_state *prealloc = NULL;
729 struct rb_node *node;
730 int err = 0;
731 u64 last_start;
732 u64 last_end;
733
734 bits |= EXTENT_FIRST_DELALLOC;
735 again:
736 if (!prealloc && (mask & __GFP_WAIT)) {
737 prealloc = alloc_extent_state(mask);
738 BUG_ON(!prealloc);
739 }
740
741 spin_lock(&tree->lock);
742 if (cached_state && *cached_state) {
743 state = *cached_state;
744 if (state->start <= start && state->end > start &&
745 state->tree) {
746 node = &state->rb_node;
747 goto hit_next;
748 }
749 }
750 /*
751 * this search will find all the extents that end after
752 * our range starts.
753 */
754 node = tree_search(tree, start);
755 if (!node) {
756 prealloc = alloc_extent_state_atomic(prealloc);
757 BUG_ON(!prealloc);
758 err = insert_state(tree, prealloc, start, end, &bits);
759 prealloc = NULL;
760 BUG_ON(err == -EEXIST);
761 goto out;
762 }
763 state = rb_entry(node, struct extent_state, rb_node);
764 hit_next:
765 last_start = state->start;
766 last_end = state->end;
767
768 /*
769 * | ---- desired range ---- |
770 * | state |
771 *
772 * Just lock what we found and keep going
773 */
774 if (state->start == start && state->end <= end) {
775 struct rb_node *next_node;
776 if (state->state & exclusive_bits) {
777 *failed_start = state->start;
778 err = -EEXIST;
779 goto out;
780 }
781
782 err = set_state_bits(tree, state, &bits);
783 if (err)
784 goto out;
785
786 cache_state(state, cached_state);
787 merge_state(tree, state);
788 if (last_end == (u64)-1)
789 goto out;
790
791 start = last_end + 1;
792 next_node = rb_next(&state->rb_node);
793 if (next_node && start < end && prealloc && !need_resched()) {
794 state = rb_entry(next_node, struct extent_state,
795 rb_node);
796 if (state->start == start)
797 goto hit_next;
798 }
799 goto search_again;
800 }
801
802 /*
803 * | ---- desired range ---- |
804 * | state |
805 * or
806 * | ------------- state -------------- |
807 *
808 * We need to split the extent we found, and may flip bits on
809 * second half.
810 *
811 * If the extent we found extends past our
812 * range, we just split and search again. It'll get split
813 * again the next time though.
814 *
815 * If the extent we found is inside our range, we set the
816 * desired bit on it.
817 */
818 if (state->start < start) {
819 if (state->state & exclusive_bits) {
820 *failed_start = start;
821 err = -EEXIST;
822 goto out;
823 }
824
825 prealloc = alloc_extent_state_atomic(prealloc);
826 BUG_ON(!prealloc);
827 err = split_state(tree, state, prealloc, start);
828 BUG_ON(err == -EEXIST);
829 prealloc = NULL;
830 if (err)
831 goto out;
832 if (state->end <= end) {
833 err = set_state_bits(tree, state, &bits);
834 if (err)
835 goto out;
836 cache_state(state, cached_state);
837 merge_state(tree, state);
838 if (last_end == (u64)-1)
839 goto out;
840 start = last_end + 1;
841 }
842 goto search_again;
843 }
844 /*
845 * | ---- desired range ---- |
846 * | state | or | state |
847 *
848 * There's a hole, we need to insert something in it and
849 * ignore the extent we found.
850 */
851 if (state->start > start) {
852 u64 this_end;
853 if (end < last_start)
854 this_end = end;
855 else
856 this_end = last_start - 1;
857
858 prealloc = alloc_extent_state_atomic(prealloc);
859 BUG_ON(!prealloc);
860
861 /*
862 * Avoid to free 'prealloc' if it can be merged with
863 * the later extent.
864 */
865 err = insert_state(tree, prealloc, start, this_end,
866 &bits);
867 BUG_ON(err == -EEXIST);
868 if (err) {
869 free_extent_state(prealloc);
870 prealloc = NULL;
871 goto out;
872 }
873 cache_state(prealloc, cached_state);
874 prealloc = NULL;
875 start = this_end + 1;
876 goto search_again;
877 }
878 /*
879 * | ---- desired range ---- |
880 * | state |
881 * We need to split the extent, and set the bit
882 * on the first half
883 */
884 if (state->start <= end && state->end > end) {
885 if (state->state & exclusive_bits) {
886 *failed_start = start;
887 err = -EEXIST;
888 goto out;
889 }
890
891 prealloc = alloc_extent_state_atomic(prealloc);
892 BUG_ON(!prealloc);
893 err = split_state(tree, state, prealloc, end + 1);
894 BUG_ON(err == -EEXIST);
895
896 err = set_state_bits(tree, prealloc, &bits);
897 if (err) {
898 prealloc = NULL;
899 goto out;
900 }
901 cache_state(prealloc, cached_state);
902 merge_state(tree, prealloc);
903 prealloc = NULL;
904 goto out;
905 }
906
907 goto search_again;
908
909 out:
910 spin_unlock(&tree->lock);
911 if (prealloc)
912 free_extent_state(prealloc);
913
914 return err;
915
916 search_again:
917 if (start > end)
918 goto out;
919 spin_unlock(&tree->lock);
920 if (mask & __GFP_WAIT)
921 cond_resched();
922 goto again;
923 }
924
925 /* wrappers around set/clear extent bit */
926 int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
927 gfp_t mask)
928 {
929 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
930 NULL, mask);
931 }
932
933 int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
934 int bits, gfp_t mask)
935 {
936 return set_extent_bit(tree, start, end, bits, 0, NULL,
937 NULL, mask);
938 }
939
940 int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
941 int bits, gfp_t mask)
942 {
943 return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
944 }
945
946 int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
947 struct extent_state **cached_state, gfp_t mask)
948 {
949 return set_extent_bit(tree, start, end,
950 EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
951 0, NULL, cached_state, mask);
952 }
953
954 int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
955 gfp_t mask)
956 {
957 return clear_extent_bit(tree, start, end,
958 EXTENT_DIRTY | EXTENT_DELALLOC |
959 EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
960 }
961
962 int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
963 gfp_t mask)
964 {
965 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
966 NULL, mask);
967 }
968
969 int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
970 struct extent_state **cached_state, gfp_t mask)
971 {
972 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0,
973 NULL, cached_state, mask);
974 }
975
976 static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
977 u64 end, struct extent_state **cached_state,
978 gfp_t mask)
979 {
980 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
981 cached_state, mask);
982 }
983
984 /*
985 * either insert or lock state struct between start and end use mask to tell
986 * us if waiting is desired.
987 */
988 int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
989 int bits, struct extent_state **cached_state, gfp_t mask)
990 {
991 int err;
992 u64 failed_start;
993 while (1) {
994 err = set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
995 EXTENT_LOCKED, &failed_start,
996 cached_state, mask);
997 if (err == -EEXIST && (mask & __GFP_WAIT)) {
998 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
999 start = failed_start;
1000 } else {
1001 break;
1002 }
1003 WARN_ON(start > end);
1004 }
1005 return err;
1006 }
1007
1008 int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
1009 {
1010 return lock_extent_bits(tree, start, end, 0, NULL, mask);
1011 }
1012
1013 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
1014 gfp_t mask)
1015 {
1016 int err;
1017 u64 failed_start;
1018
1019 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
1020 &failed_start, NULL, mask);
1021 if (err == -EEXIST) {
1022 if (failed_start > start)
1023 clear_extent_bit(tree, start, failed_start - 1,
1024 EXTENT_LOCKED, 1, 0, NULL, mask);
1025 return 0;
1026 }
1027 return 1;
1028 }
1029
1030 int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
1031 struct extent_state **cached, gfp_t mask)
1032 {
1033 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
1034 mask);
1035 }
1036
1037 int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
1038 {
1039 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1040 mask);
1041 }
1042
1043 /*
1044 * helper function to set both pages and extents in the tree writeback
1045 */
1046 static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1047 {
1048 unsigned long index = start >> PAGE_CACHE_SHIFT;
1049 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1050 struct page *page;
1051
1052 while (index <= end_index) {
1053 page = find_get_page(tree->mapping, index);
1054 BUG_ON(!page);
1055 set_page_writeback(page);
1056 page_cache_release(page);
1057 index++;
1058 }
1059 return 0;
1060 }
1061
1062 /*
1063 * find the first offset in the io tree with 'bits' set. zero is
1064 * returned if we find something, and *start_ret and *end_ret are
1065 * set to reflect the state struct that was found.
1066 *
1067 * If nothing was found, 1 is returned, < 0 on error
1068 */
1069 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1070 u64 *start_ret, u64 *end_ret, int bits)
1071 {
1072 struct rb_node *node;
1073 struct extent_state *state;
1074 int ret = 1;
1075
1076 spin_lock(&tree->lock);
1077 /*
1078 * this search will find all the extents that end after
1079 * our range starts.
1080 */
1081 node = tree_search(tree, start);
1082 if (!node)
1083 goto out;
1084
1085 while (1) {
1086 state = rb_entry(node, struct extent_state, rb_node);
1087 if (state->end >= start && (state->state & bits)) {
1088 *start_ret = state->start;
1089 *end_ret = state->end;
1090 ret = 0;
1091 break;
1092 }
1093 node = rb_next(node);
1094 if (!node)
1095 break;
1096 }
1097 out:
1098 spin_unlock(&tree->lock);
1099 return ret;
1100 }
1101
1102 /* find the first state struct with 'bits' set after 'start', and
1103 * return it. tree->lock must be held. NULL will returned if
1104 * nothing was found after 'start'
1105 */
1106 struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
1107 u64 start, int bits)
1108 {
1109 struct rb_node *node;
1110 struct extent_state *state;
1111
1112 /*
1113 * this search will find all the extents that end after
1114 * our range starts.
1115 */
1116 node = tree_search(tree, start);
1117 if (!node)
1118 goto out;
1119
1120 while (1) {
1121 state = rb_entry(node, struct extent_state, rb_node);
1122 if (state->end >= start && (state->state & bits))
1123 return state;
1124
1125 node = rb_next(node);
1126 if (!node)
1127 break;
1128 }
1129 out:
1130 return NULL;
1131 }
1132
1133 /*
1134 * find a contiguous range of bytes in the file marked as delalloc, not
1135 * more than 'max_bytes'. start and end are used to return the range,
1136 *
1137 * 1 is returned if we find something, 0 if nothing was in the tree
1138 */
1139 static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1140 u64 *start, u64 *end, u64 max_bytes,
1141 struct extent_state **cached_state)
1142 {
1143 struct rb_node *node;
1144 struct extent_state *state;
1145 u64 cur_start = *start;
1146 u64 found = 0;
1147 u64 total_bytes = 0;
1148
1149 spin_lock(&tree->lock);
1150
1151 /*
1152 * this search will find all the extents that end after
1153 * our range starts.
1154 */
1155 node = tree_search(tree, cur_start);
1156 if (!node) {
1157 if (!found)
1158 *end = (u64)-1;
1159 goto out;
1160 }
1161
1162 while (1) {
1163 state = rb_entry(node, struct extent_state, rb_node);
1164 if (found && (state->start != cur_start ||
1165 (state->state & EXTENT_BOUNDARY))) {
1166 goto out;
1167 }
1168 if (!(state->state & EXTENT_DELALLOC)) {
1169 if (!found)
1170 *end = state->end;
1171 goto out;
1172 }
1173 if (!found) {
1174 *start = state->start;
1175 *cached_state = state;
1176 atomic_inc(&state->refs);
1177 }
1178 found++;
1179 *end = state->end;
1180 cur_start = state->end + 1;
1181 node = rb_next(node);
1182 if (!node)
1183 break;
1184 total_bytes += state->end - state->start + 1;
1185 if (total_bytes >= max_bytes)
1186 break;
1187 }
1188 out:
1189 spin_unlock(&tree->lock);
1190 return found;
1191 }
1192
1193 static noinline int __unlock_for_delalloc(struct inode *inode,
1194 struct page *locked_page,
1195 u64 start, u64 end)
1196 {
1197 int ret;
1198 struct page *pages[16];
1199 unsigned long index = start >> PAGE_CACHE_SHIFT;
1200 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1201 unsigned long nr_pages = end_index - index + 1;
1202 int i;
1203
1204 if (index == locked_page->index && end_index == index)
1205 return 0;
1206
1207 while (nr_pages > 0) {
1208 ret = find_get_pages_contig(inode->i_mapping, index,
1209 min_t(unsigned long, nr_pages,
1210 ARRAY_SIZE(pages)), pages);
1211 for (i = 0; i < ret; i++) {
1212 if (pages[i] != locked_page)
1213 unlock_page(pages[i]);
1214 page_cache_release(pages[i]);
1215 }
1216 nr_pages -= ret;
1217 index += ret;
1218 cond_resched();
1219 }
1220 return 0;
1221 }
1222
1223 static noinline int lock_delalloc_pages(struct inode *inode,
1224 struct page *locked_page,
1225 u64 delalloc_start,
1226 u64 delalloc_end)
1227 {
1228 unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
1229 unsigned long start_index = index;
1230 unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
1231 unsigned long pages_locked = 0;
1232 struct page *pages[16];
1233 unsigned long nrpages;
1234 int ret;
1235 int i;
1236
1237 /* the caller is responsible for locking the start index */
1238 if (index == locked_page->index && index == end_index)
1239 return 0;
1240
1241 /* skip the page at the start index */
1242 nrpages = end_index - index + 1;
1243 while (nrpages > 0) {
1244 ret = find_get_pages_contig(inode->i_mapping, index,
1245 min_t(unsigned long,
1246 nrpages, ARRAY_SIZE(pages)), pages);
1247 if (ret == 0) {
1248 ret = -EAGAIN;
1249 goto done;
1250 }
1251 /* now we have an array of pages, lock them all */
1252 for (i = 0; i < ret; i++) {
1253 /*
1254 * the caller is taking responsibility for
1255 * locked_page
1256 */
1257 if (pages[i] != locked_page) {
1258 lock_page(pages[i]);
1259 if (!PageDirty(pages[i]) ||
1260 pages[i]->mapping != inode->i_mapping) {
1261 ret = -EAGAIN;
1262 unlock_page(pages[i]);
1263 page_cache_release(pages[i]);
1264 goto done;
1265 }
1266 }
1267 page_cache_release(pages[i]);
1268 pages_locked++;
1269 }
1270 nrpages -= ret;
1271 index += ret;
1272 cond_resched();
1273 }
1274 ret = 0;
1275 done:
1276 if (ret && pages_locked) {
1277 __unlock_for_delalloc(inode, locked_page,
1278 delalloc_start,
1279 ((u64)(start_index + pages_locked - 1)) <<
1280 PAGE_CACHE_SHIFT);
1281 }
1282 return ret;
1283 }
1284
1285 /*
1286 * find a contiguous range of bytes in the file marked as delalloc, not
1287 * more than 'max_bytes'. start and end are used to return the range,
1288 *
1289 * 1 is returned if we find something, 0 if nothing was in the tree
1290 */
1291 static noinline u64 find_lock_delalloc_range(struct inode *inode,
1292 struct extent_io_tree *tree,
1293 struct page *locked_page,
1294 u64 *start, u64 *end,
1295 u64 max_bytes)
1296 {
1297 u64 delalloc_start;
1298 u64 delalloc_end;
1299 u64 found;
1300 struct extent_state *cached_state = NULL;
1301 int ret;
1302 int loops = 0;
1303
1304 again:
1305 /* step one, find a bunch of delalloc bytes starting at start */
1306 delalloc_start = *start;
1307 delalloc_end = 0;
1308 found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1309 max_bytes, &cached_state);
1310 if (!found || delalloc_end <= *start) {
1311 *start = delalloc_start;
1312 *end = delalloc_end;
1313 free_extent_state(cached_state);
1314 return found;
1315 }
1316
1317 /*
1318 * start comes from the offset of locked_page. We have to lock
1319 * pages in order, so we can't process delalloc bytes before
1320 * locked_page
1321 */
1322 if (delalloc_start < *start)
1323 delalloc_start = *start;
1324
1325 /*
1326 * make sure to limit the number of pages we try to lock down
1327 * if we're looping.
1328 */
1329 if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1330 delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
1331
1332 /* step two, lock all the pages after the page that has start */
1333 ret = lock_delalloc_pages(inode, locked_page,
1334 delalloc_start, delalloc_end);
1335 if (ret == -EAGAIN) {
1336 /* some of the pages are gone, lets avoid looping by
1337 * shortening the size of the delalloc range we're searching
1338 */
1339 free_extent_state(cached_state);
1340 if (!loops) {
1341 unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
1342 max_bytes = PAGE_CACHE_SIZE - offset;
1343 loops = 1;
1344 goto again;
1345 } else {
1346 found = 0;
1347 goto out_failed;
1348 }
1349 }
1350 BUG_ON(ret);
1351
1352 /* step three, lock the state bits for the whole range */
1353 lock_extent_bits(tree, delalloc_start, delalloc_end,
1354 0, &cached_state, GFP_NOFS);
1355
1356 /* then test to make sure it is all still delalloc */
1357 ret = test_range_bit(tree, delalloc_start, delalloc_end,
1358 EXTENT_DELALLOC, 1, cached_state);
1359 if (!ret) {
1360 unlock_extent_cached(tree, delalloc_start, delalloc_end,
1361 &cached_state, GFP_NOFS);
1362 __unlock_for_delalloc(inode, locked_page,
1363 delalloc_start, delalloc_end);
1364 cond_resched();
1365 goto again;
1366 }
1367 free_extent_state(cached_state);
1368 *start = delalloc_start;
1369 *end = delalloc_end;
1370 out_failed:
1371 return found;
1372 }
1373
1374 int extent_clear_unlock_delalloc(struct inode *inode,
1375 struct extent_io_tree *tree,
1376 u64 start, u64 end, struct page *locked_page,
1377 unsigned long op)
1378 {
1379 int ret;
1380 struct page *pages[16];
1381 unsigned long index = start >> PAGE_CACHE_SHIFT;
1382 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1383 unsigned long nr_pages = end_index - index + 1;
1384 int i;
1385 int clear_bits = 0;
1386
1387 if (op & EXTENT_CLEAR_UNLOCK)
1388 clear_bits |= EXTENT_LOCKED;
1389 if (op & EXTENT_CLEAR_DIRTY)
1390 clear_bits |= EXTENT_DIRTY;
1391
1392 if (op & EXTENT_CLEAR_DELALLOC)
1393 clear_bits |= EXTENT_DELALLOC;
1394
1395 clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1396 if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
1397 EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
1398 EXTENT_SET_PRIVATE2)))
1399 return 0;
1400
1401 while (nr_pages > 0) {
1402 ret = find_get_pages_contig(inode->i_mapping, index,
1403 min_t(unsigned long,
1404 nr_pages, ARRAY_SIZE(pages)), pages);
1405 for (i = 0; i < ret; i++) {
1406
1407 if (op & EXTENT_SET_PRIVATE2)
1408 SetPagePrivate2(pages[i]);
1409
1410 if (pages[i] == locked_page) {
1411 page_cache_release(pages[i]);
1412 continue;
1413 }
1414 if (op & EXTENT_CLEAR_DIRTY)
1415 clear_page_dirty_for_io(pages[i]);
1416 if (op & EXTENT_SET_WRITEBACK)
1417 set_page_writeback(pages[i]);
1418 if (op & EXTENT_END_WRITEBACK)
1419 end_page_writeback(pages[i]);
1420 if (op & EXTENT_CLEAR_UNLOCK_PAGE)
1421 unlock_page(pages[i]);
1422 page_cache_release(pages[i]);
1423 }
1424 nr_pages -= ret;
1425 index += ret;
1426 cond_resched();
1427 }
1428 return 0;
1429 }
1430
1431 /*
1432 * count the number of bytes in the tree that have a given bit(s)
1433 * set. This can be fairly slow, except for EXTENT_DIRTY which is
1434 * cached. The total number found is returned.
1435 */
1436 u64 count_range_bits(struct extent_io_tree *tree,
1437 u64 *start, u64 search_end, u64 max_bytes,
1438 unsigned long bits, int contig)
1439 {
1440 struct rb_node *node;
1441 struct extent_state *state;
1442 u64 cur_start = *start;
1443 u64 total_bytes = 0;
1444 u64 last = 0;
1445 int found = 0;
1446
1447 if (search_end <= cur_start) {
1448 WARN_ON(1);
1449 return 0;
1450 }
1451
1452 spin_lock(&tree->lock);
1453 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1454 total_bytes = tree->dirty_bytes;
1455 goto out;
1456 }
1457 /*
1458 * this search will find all the extents that end after
1459 * our range starts.
1460 */
1461 node = tree_search(tree, cur_start);
1462 if (!node)
1463 goto out;
1464
1465 while (1) {
1466 state = rb_entry(node, struct extent_state, rb_node);
1467 if (state->start > search_end)
1468 break;
1469 if (contig && found && state->start > last + 1)
1470 break;
1471 if (state->end >= cur_start && (state->state & bits) == bits) {
1472 total_bytes += min(search_end, state->end) + 1 -
1473 max(cur_start, state->start);
1474 if (total_bytes >= max_bytes)
1475 break;
1476 if (!found) {
1477 *start = max(cur_start, state->start);
1478 found = 1;
1479 }
1480 last = state->end;
1481 } else if (contig && found) {
1482 break;
1483 }
1484 node = rb_next(node);
1485 if (!node)
1486 break;
1487 }
1488 out:
1489 spin_unlock(&tree->lock);
1490 return total_bytes;
1491 }
1492
1493 /*
1494 * set the private field for a given byte offset in the tree. If there isn't
1495 * an extent_state there already, this does nothing.
1496 */
1497 int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1498 {
1499 struct rb_node *node;
1500 struct extent_state *state;
1501 int ret = 0;
1502
1503 spin_lock(&tree->lock);
1504 /*
1505 * this search will find all the extents that end after
1506 * our range starts.
1507 */
1508 node = tree_search(tree, start);
1509 if (!node) {
1510 ret = -ENOENT;
1511 goto out;
1512 }
1513 state = rb_entry(node, struct extent_state, rb_node);
1514 if (state->start != start) {
1515 ret = -ENOENT;
1516 goto out;
1517 }
1518 state->private = private;
1519 out:
1520 spin_unlock(&tree->lock);
1521 return ret;
1522 }
1523
1524 int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1525 {
1526 struct rb_node *node;
1527 struct extent_state *state;
1528 int ret = 0;
1529
1530 spin_lock(&tree->lock);
1531 /*
1532 * this search will find all the extents that end after
1533 * our range starts.
1534 */
1535 node = tree_search(tree, start);
1536 if (!node) {
1537 ret = -ENOENT;
1538 goto out;
1539 }
1540 state = rb_entry(node, struct extent_state, rb_node);
1541 if (state->start != start) {
1542 ret = -ENOENT;
1543 goto out;
1544 }
1545 *private = state->private;
1546 out:
1547 spin_unlock(&tree->lock);
1548 return ret;
1549 }
1550
1551 /*
1552 * searches a range in the state tree for a given mask.
1553 * If 'filled' == 1, this returns 1 only if every extent in the tree
1554 * has the bits set. Otherwise, 1 is returned if any bit in the
1555 * range is found set.
1556 */
1557 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1558 int bits, int filled, struct extent_state *cached)
1559 {
1560 struct extent_state *state = NULL;
1561 struct rb_node *node;
1562 int bitset = 0;
1563
1564 spin_lock(&tree->lock);
1565 if (cached && cached->tree && cached->start <= start &&
1566 cached->end > start)
1567 node = &cached->rb_node;
1568 else
1569 node = tree_search(tree, start);
1570 while (node && start <= end) {
1571 state = rb_entry(node, struct extent_state, rb_node);
1572
1573 if (filled && state->start > start) {
1574 bitset = 0;
1575 break;
1576 }
1577
1578 if (state->start > end)
1579 break;
1580
1581 if (state->state & bits) {
1582 bitset = 1;
1583 if (!filled)
1584 break;
1585 } else if (filled) {
1586 bitset = 0;
1587 break;
1588 }
1589
1590 if (state->end == (u64)-1)
1591 break;
1592
1593 start = state->end + 1;
1594 if (start > end)
1595 break;
1596 node = rb_next(node);
1597 if (!node) {
1598 if (filled)
1599 bitset = 0;
1600 break;
1601 }
1602 }
1603 spin_unlock(&tree->lock);
1604 return bitset;
1605 }
1606
1607 /*
1608 * helper function to set a given page up to date if all the
1609 * extents in the tree for that page are up to date
1610 */
1611 static int check_page_uptodate(struct extent_io_tree *tree,
1612 struct page *page)
1613 {
1614 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1615 u64 end = start + PAGE_CACHE_SIZE - 1;
1616 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1617 SetPageUptodate(page);
1618 return 0;
1619 }
1620
1621 /*
1622 * helper function to unlock a page if all the extents in the tree
1623 * for that page are unlocked
1624 */
1625 static int check_page_locked(struct extent_io_tree *tree,
1626 struct page *page)
1627 {
1628 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1629 u64 end = start + PAGE_CACHE_SIZE - 1;
1630 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
1631 unlock_page(page);
1632 return 0;
1633 }
1634
1635 /*
1636 * helper function to end page writeback if all the extents
1637 * in the tree for that page are done with writeback
1638 */
1639 static int check_page_writeback(struct extent_io_tree *tree,
1640 struct page *page)
1641 {
1642 end_page_writeback(page);
1643 return 0;
1644 }
1645
1646 /* lots and lots of room for performance fixes in the end_bio funcs */
1647
1648 /*
1649 * after a writepage IO is done, we need to:
1650 * clear the uptodate bits on error
1651 * clear the writeback bits in the extent tree for this IO
1652 * end_page_writeback if the page has no more pending IO
1653 *
1654 * Scheduling is not allowed, so the extent state tree is expected
1655 * to have one and only one object corresponding to this IO.
1656 */
1657 static void end_bio_extent_writepage(struct bio *bio, int err)
1658 {
1659 int uptodate = err == 0;
1660 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1661 struct extent_io_tree *tree;
1662 u64 start;
1663 u64 end;
1664 int whole_page;
1665 int ret;
1666
1667 do {
1668 struct page *page = bvec->bv_page;
1669 tree = &BTRFS_I(page->mapping->host)->io_tree;
1670
1671 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1672 bvec->bv_offset;
1673 end = start + bvec->bv_len - 1;
1674
1675 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1676 whole_page = 1;
1677 else
1678 whole_page = 0;
1679
1680 if (--bvec >= bio->bi_io_vec)
1681 prefetchw(&bvec->bv_page->flags);
1682 if (tree->ops && tree->ops->writepage_end_io_hook) {
1683 ret = tree->ops->writepage_end_io_hook(page, start,
1684 end, NULL, uptodate);
1685 if (ret)
1686 uptodate = 0;
1687 }
1688
1689 if (!uptodate && tree->ops &&
1690 tree->ops->writepage_io_failed_hook) {
1691 ret = tree->ops->writepage_io_failed_hook(bio, page,
1692 start, end, NULL);
1693 if (ret == 0) {
1694 uptodate = (err == 0);
1695 continue;
1696 }
1697 }
1698
1699 if (!uptodate) {
1700 clear_extent_uptodate(tree, start, end, NULL, GFP_NOFS);
1701 ClearPageUptodate(page);
1702 SetPageError(page);
1703 }
1704
1705 if (whole_page)
1706 end_page_writeback(page);
1707 else
1708 check_page_writeback(tree, page);
1709 } while (bvec >= bio->bi_io_vec);
1710
1711 bio_put(bio);
1712 }
1713
1714 /*
1715 * after a readpage IO is done, we need to:
1716 * clear the uptodate bits on error
1717 * set the uptodate bits if things worked
1718 * set the page up to date if all extents in the tree are uptodate
1719 * clear the lock bit in the extent tree
1720 * unlock the page if there are no other extents locked for it
1721 *
1722 * Scheduling is not allowed, so the extent state tree is expected
1723 * to have one and only one object corresponding to this IO.
1724 */
1725 static void end_bio_extent_readpage(struct bio *bio, int err)
1726 {
1727 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1728 struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
1729 struct bio_vec *bvec = bio->bi_io_vec;
1730 struct extent_io_tree *tree;
1731 u64 start;
1732 u64 end;
1733 int whole_page;
1734 int ret;
1735
1736 if (err)
1737 uptodate = 0;
1738
1739 do {
1740 struct page *page = bvec->bv_page;
1741 struct extent_state *cached = NULL;
1742 struct extent_state *state;
1743
1744 tree = &BTRFS_I(page->mapping->host)->io_tree;
1745
1746 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1747 bvec->bv_offset;
1748 end = start + bvec->bv_len - 1;
1749
1750 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1751 whole_page = 1;
1752 else
1753 whole_page = 0;
1754
1755 if (++bvec <= bvec_end)
1756 prefetchw(&bvec->bv_page->flags);
1757
1758 spin_lock(&tree->lock);
1759 state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
1760 if (state && state->start == start) {
1761 /*
1762 * take a reference on the state, unlock will drop
1763 * the ref
1764 */
1765 cache_state(state, &cached);
1766 }
1767 spin_unlock(&tree->lock);
1768
1769 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1770 ret = tree->ops->readpage_end_io_hook(page, start, end,
1771 state);
1772 if (ret)
1773 uptodate = 0;
1774 }
1775 if (!uptodate && tree->ops &&
1776 tree->ops->readpage_io_failed_hook) {
1777 ret = tree->ops->readpage_io_failed_hook(bio, page,
1778 start, end, NULL);
1779 if (ret == 0) {
1780 uptodate =
1781 test_bit(BIO_UPTODATE, &bio->bi_flags);
1782 if (err)
1783 uptodate = 0;
1784 uncache_state(&cached);
1785 continue;
1786 }
1787 }
1788
1789 if (uptodate) {
1790 set_extent_uptodate(tree, start, end, &cached,
1791 GFP_ATOMIC);
1792 }
1793 unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
1794
1795 if (whole_page) {
1796 if (uptodate) {
1797 SetPageUptodate(page);
1798 } else {
1799 ClearPageUptodate(page);
1800 SetPageError(page);
1801 }
1802 unlock_page(page);
1803 } else {
1804 if (uptodate) {
1805 check_page_uptodate(tree, page);
1806 } else {
1807 ClearPageUptodate(page);
1808 SetPageError(page);
1809 }
1810 check_page_locked(tree, page);
1811 }
1812 } while (bvec <= bvec_end);
1813
1814 bio_put(bio);
1815 }
1816
1817 struct bio *
1818 btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
1819 gfp_t gfp_flags)
1820 {
1821 struct bio *bio;
1822
1823 bio = bio_alloc(gfp_flags, nr_vecs);
1824
1825 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
1826 while (!bio && (nr_vecs /= 2))
1827 bio = bio_alloc(gfp_flags, nr_vecs);
1828 }
1829
1830 if (bio) {
1831 bio->bi_size = 0;
1832 bio->bi_bdev = bdev;
1833 bio->bi_sector = first_sector;
1834 }
1835 return bio;
1836 }
1837
1838 static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
1839 unsigned long bio_flags)
1840 {
1841 int ret = 0;
1842 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1843 struct page *page = bvec->bv_page;
1844 struct extent_io_tree *tree = bio->bi_private;
1845 u64 start;
1846
1847 start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1848
1849 bio->bi_private = NULL;
1850
1851 bio_get(bio);
1852
1853 if (tree->ops && tree->ops->submit_bio_hook)
1854 ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1855 mirror_num, bio_flags, start);
1856 else
1857 submit_bio(rw, bio);
1858 if (bio_flagged(bio, BIO_EOPNOTSUPP))
1859 ret = -EOPNOTSUPP;
1860 bio_put(bio);
1861 return ret;
1862 }
1863
1864 static int submit_extent_page(int rw, struct extent_io_tree *tree,
1865 struct page *page, sector_t sector,
1866 size_t size, unsigned long offset,
1867 struct block_device *bdev,
1868 struct bio **bio_ret,
1869 unsigned long max_pages,
1870 bio_end_io_t end_io_func,
1871 int mirror_num,
1872 unsigned long prev_bio_flags,
1873 unsigned long bio_flags)
1874 {
1875 int ret = 0;
1876 struct bio *bio;
1877 int nr;
1878 int contig = 0;
1879 int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
1880 int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
1881 size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
1882
1883 if (bio_ret && *bio_ret) {
1884 bio = *bio_ret;
1885 if (old_compressed)
1886 contig = bio->bi_sector == sector;
1887 else
1888 contig = bio->bi_sector + (bio->bi_size >> 9) ==
1889 sector;
1890
1891 if (prev_bio_flags != bio_flags || !contig ||
1892 (tree->ops && tree->ops->merge_bio_hook &&
1893 tree->ops->merge_bio_hook(page, offset, page_size, bio,
1894 bio_flags)) ||
1895 bio_add_page(bio, page, page_size, offset) < page_size) {
1896 ret = submit_one_bio(rw, bio, mirror_num,
1897 prev_bio_flags);
1898 bio = NULL;
1899 } else {
1900 return 0;
1901 }
1902 }
1903 if (this_compressed)
1904 nr = BIO_MAX_PAGES;
1905 else
1906 nr = bio_get_nr_vecs(bdev);
1907
1908 bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1909 if (!bio)
1910 return -ENOMEM;
1911
1912 bio_add_page(bio, page, page_size, offset);
1913 bio->bi_end_io = end_io_func;
1914 bio->bi_private = tree;
1915
1916 if (bio_ret)
1917 *bio_ret = bio;
1918 else
1919 ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
1920
1921 return ret;
1922 }
1923
1924 void set_page_extent_mapped(struct page *page)
1925 {
1926 if (!PagePrivate(page)) {
1927 SetPagePrivate(page);
1928 page_cache_get(page);
1929 set_page_private(page, EXTENT_PAGE_PRIVATE);
1930 }
1931 }
1932
1933 static void set_page_extent_head(struct page *page, unsigned long len)
1934 {
1935 WARN_ON(!PagePrivate(page));
1936 set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
1937 }
1938
1939 /*
1940 * basic readpage implementation. Locked extent state structs are inserted
1941 * into the tree that are removed when the IO is done (by the end_io
1942 * handlers)
1943 */
1944 static int __extent_read_full_page(struct extent_io_tree *tree,
1945 struct page *page,
1946 get_extent_t *get_extent,
1947 struct bio **bio, int mirror_num,
1948 unsigned long *bio_flags)
1949 {
1950 struct inode *inode = page->mapping->host;
1951 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1952 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1953 u64 end;
1954 u64 cur = start;
1955 u64 extent_offset;
1956 u64 last_byte = i_size_read(inode);
1957 u64 block_start;
1958 u64 cur_end;
1959 sector_t sector;
1960 struct extent_map *em;
1961 struct block_device *bdev;
1962 struct btrfs_ordered_extent *ordered;
1963 int ret;
1964 int nr = 0;
1965 size_t pg_offset = 0;
1966 size_t iosize;
1967 size_t disk_io_size;
1968 size_t blocksize = inode->i_sb->s_blocksize;
1969 unsigned long this_bio_flag = 0;
1970
1971 set_page_extent_mapped(page);
1972
1973 if (!PageUptodate(page)) {
1974 if (cleancache_get_page(page) == 0) {
1975 BUG_ON(blocksize != PAGE_SIZE);
1976 goto out;
1977 }
1978 }
1979
1980 end = page_end;
1981 while (1) {
1982 lock_extent(tree, start, end, GFP_NOFS);
1983 ordered = btrfs_lookup_ordered_extent(inode, start);
1984 if (!ordered)
1985 break;
1986 unlock_extent(tree, start, end, GFP_NOFS);
1987 btrfs_start_ordered_extent(inode, ordered, 1);
1988 btrfs_put_ordered_extent(ordered);
1989 }
1990
1991 if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
1992 char *userpage;
1993 size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);
1994
1995 if (zero_offset) {
1996 iosize = PAGE_CACHE_SIZE - zero_offset;
1997 userpage = kmap_atomic(page, KM_USER0);
1998 memset(userpage + zero_offset, 0, iosize);
1999 flush_dcache_page(page);
2000 kunmap_atomic(userpage, KM_USER0);
2001 }
2002 }
2003 while (cur <= end) {
2004 if (cur >= last_byte) {
2005 char *userpage;
2006 struct extent_state *cached = NULL;
2007
2008 iosize = PAGE_CACHE_SIZE - pg_offset;
2009 userpage = kmap_atomic(page, KM_USER0);
2010 memset(userpage + pg_offset, 0, iosize);
2011 flush_dcache_page(page);
2012 kunmap_atomic(userpage, KM_USER0);
2013 set_extent_uptodate(tree, cur, cur + iosize - 1,
2014 &cached, GFP_NOFS);
2015 unlock_extent_cached(tree, cur, cur + iosize - 1,
2016 &cached, GFP_NOFS);
2017 break;
2018 }
2019 em = get_extent(inode, page, pg_offset, cur,
2020 end - cur + 1, 0);
2021 if (IS_ERR_OR_NULL(em)) {
2022 SetPageError(page);
2023 unlock_extent(tree, cur, end, GFP_NOFS);
2024 break;
2025 }
2026 extent_offset = cur - em->start;
2027 BUG_ON(extent_map_end(em) <= cur);
2028 BUG_ON(end < cur);
2029
2030 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2031 this_bio_flag = EXTENT_BIO_COMPRESSED;
2032 extent_set_compress_type(&this_bio_flag,
2033 em->compress_type);
2034 }
2035
2036 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2037 cur_end = min(extent_map_end(em) - 1, end);
2038 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2039 if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
2040 disk_io_size = em->block_len;
2041 sector = em->block_start >> 9;
2042 } else {
2043 sector = (em->block_start + extent_offset) >> 9;
2044 disk_io_size = iosize;
2045 }
2046 bdev = em->bdev;
2047 block_start = em->block_start;
2048 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2049 block_start = EXTENT_MAP_HOLE;
2050 free_extent_map(em);
2051 em = NULL;
2052
2053 /* we've found a hole, just zero and go on */
2054 if (block_start == EXTENT_MAP_HOLE) {
2055 char *userpage;
2056 struct extent_state *cached = NULL;
2057
2058 userpage = kmap_atomic(page, KM_USER0);
2059 memset(userpage + pg_offset, 0, iosize);
2060 flush_dcache_page(page);
2061 kunmap_atomic(userpage, KM_USER0);
2062
2063 set_extent_uptodate(tree, cur, cur + iosize - 1,
2064 &cached, GFP_NOFS);
2065 unlock_extent_cached(tree, cur, cur + iosize - 1,
2066 &cached, GFP_NOFS);
2067 cur = cur + iosize;
2068 pg_offset += iosize;
2069 continue;
2070 }
2071 /* the get_extent function already copied into the page */
2072 if (test_range_bit(tree, cur, cur_end,
2073 EXTENT_UPTODATE, 1, NULL)) {
2074 check_page_uptodate(tree, page);
2075 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2076 cur = cur + iosize;
2077 pg_offset += iosize;
2078 continue;
2079 }
2080 /* we have an inline extent but it didn't get marked up
2081 * to date. Error out
2082 */
2083 if (block_start == EXTENT_MAP_INLINE) {
2084 SetPageError(page);
2085 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
2086 cur = cur + iosize;
2087 pg_offset += iosize;
2088 continue;
2089 }
2090
2091 ret = 0;
2092 if (tree->ops && tree->ops->readpage_io_hook) {
2093 ret = tree->ops->readpage_io_hook(page, cur,
2094 cur + iosize - 1);
2095 }
2096 if (!ret) {
2097 unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
2098 pnr -= page->index;
2099 ret = submit_extent_page(READ, tree, page,
2100 sector, disk_io_size, pg_offset,
2101 bdev, bio, pnr,
2102 end_bio_extent_readpage, mirror_num,
2103 *bio_flags,
2104 this_bio_flag);
2105 nr++;
2106 *bio_flags = this_bio_flag;
2107 }
2108 if (ret)
2109 SetPageError(page);
2110 cur = cur + iosize;
2111 pg_offset += iosize;
2112 }
2113 out:
2114 if (!nr) {
2115 if (!PageError(page))
2116 SetPageUptodate(page);
2117 unlock_page(page);
2118 }
2119 return 0;
2120 }
2121
2122 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
2123 get_extent_t *get_extent)
2124 {
2125 struct bio *bio = NULL;
2126 unsigned long bio_flags = 0;
2127 int ret;
2128
2129 ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
2130 &bio_flags);
2131 if (bio)
2132 ret = submit_one_bio(READ, bio, 0, bio_flags);
2133 return ret;
2134 }
2135
2136 static noinline void update_nr_written(struct page *page,
2137 struct writeback_control *wbc,
2138 unsigned long nr_written)
2139 {
2140 wbc->nr_to_write -= nr_written;
2141 if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
2142 wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
2143 page->mapping->writeback_index = page->index + nr_written;
2144 }
2145
2146 /*
2147 * the writepage semantics are similar to regular writepage. extent
2148 * records are inserted to lock ranges in the tree, and as dirty areas
2149 * are found, they are marked writeback. Then the lock bits are removed
2150 * and the end_io handler clears the writeback ranges
2151 */
2152 static int __extent_writepage(struct page *page, struct writeback_control *wbc,
2153 void *data)
2154 {
2155 struct inode *inode = page->mapping->host;
2156 struct extent_page_data *epd = data;
2157 struct extent_io_tree *tree = epd->tree;
2158 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2159 u64 delalloc_start;
2160 u64 page_end = start + PAGE_CACHE_SIZE - 1;
2161 u64 end;
2162 u64 cur = start;
2163 u64 extent_offset;
2164 u64 last_byte = i_size_read(inode);
2165 u64 block_start;
2166 u64 iosize;
2167 sector_t sector;
2168 struct extent_state *cached_state = NULL;
2169 struct extent_map *em;
2170 struct block_device *bdev;
2171 int ret;
2172 int nr = 0;
2173 size_t pg_offset = 0;
2174 size_t blocksize;
2175 loff_t i_size = i_size_read(inode);
2176 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2177 u64 nr_delalloc;
2178 u64 delalloc_end;
2179 int page_started;
2180 int compressed;
2181 int write_flags;
2182 unsigned long nr_written = 0;
2183
2184 if (wbc->sync_mode == WB_SYNC_ALL)
2185 write_flags = WRITE_SYNC;
2186 else
2187 write_flags = WRITE;
2188
2189 trace___extent_writepage(page, inode, wbc);
2190
2191 WARN_ON(!PageLocked(page));
2192 pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2193 if (page->index > end_index ||
2194 (page->index == end_index && !pg_offset)) {
2195 page->mapping->a_ops->invalidatepage(page, 0);
2196 unlock_page(page);
2197 return 0;
2198 }
2199
2200 if (page->index == end_index) {
2201 char *userpage;
2202
2203 userpage = kmap_atomic(page, KM_USER0);
2204 memset(userpage + pg_offset, 0,
2205 PAGE_CACHE_SIZE - pg_offset);
2206 kunmap_atomic(userpage, KM_USER0);
2207 flush_dcache_page(page);
2208 }
2209 pg_offset = 0;
2210
2211 set_page_extent_mapped(page);
2212
2213 delalloc_start = start;
2214 delalloc_end = 0;
2215 page_started = 0;
2216 if (!epd->extent_locked) {
2217 u64 delalloc_to_write = 0;
2218 /*
2219 * make sure the wbc mapping index is at least updated
2220 * to this page.
2221 */
2222 update_nr_written(page, wbc, 0);
2223
2224 while (delalloc_end < page_end) {
2225 nr_delalloc = find_lock_delalloc_range(inode, tree,
2226 page,
2227 &delalloc_start,
2228 &delalloc_end,
2229 128 * 1024 * 1024);
2230 if (nr_delalloc == 0) {
2231 delalloc_start = delalloc_end + 1;
2232 continue;
2233 }
2234 tree->ops->fill_delalloc(inode, page, delalloc_start,
2235 delalloc_end, &page_started,
2236 &nr_written);
2237 /*
2238 * delalloc_end is already one less than the total
2239 * length, so we don't subtract one from
2240 * PAGE_CACHE_SIZE
2241 */
2242 delalloc_to_write += (delalloc_end - delalloc_start +
2243 PAGE_CACHE_SIZE) >>
2244 PAGE_CACHE_SHIFT;
2245 delalloc_start = delalloc_end + 1;
2246 }
2247 if (wbc->nr_to_write < delalloc_to_write) {
2248 int thresh = 8192;
2249
2250 if (delalloc_to_write < thresh * 2)
2251 thresh = delalloc_to_write;
2252 wbc->nr_to_write = min_t(u64, delalloc_to_write,
2253 thresh);
2254 }
2255
2256 /* did the fill delalloc function already unlock and start
2257 * the IO?
2258 */
2259 if (page_started) {
2260 ret = 0;
2261 /*
2262 * we've unlocked the page, so we can't update
2263 * the mapping's writeback index, just update
2264 * nr_to_write.
2265 */
2266 wbc->nr_to_write -= nr_written;
2267 goto done_unlocked;
2268 }
2269 }
2270 if (tree->ops && tree->ops->writepage_start_hook) {
2271 ret = tree->ops->writepage_start_hook(page, start,
2272 page_end);
2273 if (ret == -EAGAIN) {
2274 redirty_page_for_writepage(wbc, page);
2275 update_nr_written(page, wbc, nr_written);
2276 unlock_page(page);
2277 ret = 0;
2278 goto done_unlocked;
2279 }
2280 }
2281
2282 /*
2283 * we don't want to touch the inode after unlocking the page,
2284 * so we update the mapping writeback index now
2285 */
2286 update_nr_written(page, wbc, nr_written + 1);
2287
2288 end = page_end;
2289 if (last_byte <= start) {
2290 if (tree->ops && tree->ops->writepage_end_io_hook)
2291 tree->ops->writepage_end_io_hook(page, start,
2292 page_end, NULL, 1);
2293 goto done;
2294 }
2295
2296 blocksize = inode->i_sb->s_blocksize;
2297
2298 while (cur <= end) {
2299 if (cur >= last_byte) {
2300 if (tree->ops && tree->ops->writepage_end_io_hook)
2301 tree->ops->writepage_end_io_hook(page, cur,
2302 page_end, NULL, 1);
2303 break;
2304 }
2305 em = epd->get_extent(inode, page, pg_offset, cur,
2306 end - cur + 1, 1);
2307 if (IS_ERR_OR_NULL(em)) {
2308 SetPageError(page);
2309 break;
2310 }
2311
2312 extent_offset = cur - em->start;
2313 BUG_ON(extent_map_end(em) <= cur);
2314 BUG_ON(end < cur);
2315 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2316 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2317 sector = (em->block_start + extent_offset) >> 9;
2318 bdev = em->bdev;
2319 block_start = em->block_start;
2320 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2321 free_extent_map(em);
2322 em = NULL;
2323
2324 /*
2325 * compressed and inline extents are written through other
2326 * paths in the FS
2327 */
2328 if (compressed || block_start == EXTENT_MAP_HOLE ||
2329 block_start == EXTENT_MAP_INLINE) {
2330 /*
2331 * end_io notification does not happen here for
2332 * compressed extents
2333 */
2334 if (!compressed && tree->ops &&
2335 tree->ops->writepage_end_io_hook)
2336 tree->ops->writepage_end_io_hook(page, cur,
2337 cur + iosize - 1,
2338 NULL, 1);
2339 else if (compressed) {
2340 /* we don't want to end_page_writeback on
2341 * a compressed extent. this happens
2342 * elsewhere
2343 */
2344 nr++;
2345 }
2346
2347 cur += iosize;
2348 pg_offset += iosize;
2349 continue;
2350 }
2351 /* leave this out until we have a page_mkwrite call */
2352 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2353 EXTENT_DIRTY, 0, NULL)) {
2354 cur = cur + iosize;
2355 pg_offset += iosize;
2356 continue;
2357 }
2358
2359 if (tree->ops && tree->ops->writepage_io_hook) {
2360 ret = tree->ops->writepage_io_hook(page, cur,
2361 cur + iosize - 1);
2362 } else {
2363 ret = 0;
2364 }
2365 if (ret) {
2366 SetPageError(page);
2367 } else {
2368 unsigned long max_nr = end_index + 1;
2369
2370 set_range_writeback(tree, cur, cur + iosize - 1);
2371 if (!PageWriteback(page)) {
2372 printk(KERN_ERR "btrfs warning page %lu not "
2373 "writeback, cur %llu end %llu\n",
2374 page->index, (unsigned long long)cur,
2375 (unsigned long long)end);
2376 }
2377
2378 ret = submit_extent_page(write_flags, tree, page,
2379 sector, iosize, pg_offset,
2380 bdev, &epd->bio, max_nr,
2381 end_bio_extent_writepage,
2382 0, 0, 0);
2383 if (ret)
2384 SetPageError(page);
2385 }
2386 cur = cur + iosize;
2387 pg_offset += iosize;
2388 nr++;
2389 }
2390 done:
2391 if (nr == 0) {
2392 /* make sure the mapping tag for page dirty gets cleared */
2393 set_page_writeback(page);
2394 end_page_writeback(page);
2395 }
2396 unlock_page(page);
2397
2398 done_unlocked:
2399
2400 /* drop our reference on any cached states */
2401 free_extent_state(cached_state);
2402 return 0;
2403 }
2404
2405 /**
2406 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
2407 * @mapping: address space structure to write
2408 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
2409 * @writepage: function called for each page
2410 * @data: data passed to writepage function
2411 *
2412 * If a page is already under I/O, write_cache_pages() skips it, even
2413 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
2414 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
2415 * and msync() need to guarantee that all the data which was dirty at the time
2416 * the call was made get new I/O started against them. If wbc->sync_mode is
2417 * WB_SYNC_ALL then we were called for data integrity and we must wait for
2418 * existing IO to complete.
2419 */
2420 static int extent_write_cache_pages(struct extent_io_tree *tree,
2421 struct address_space *mapping,
2422 struct writeback_control *wbc,
2423 writepage_t writepage, void *data,
2424 void (*flush_fn)(void *))
2425 {
2426 int ret = 0;
2427 int done = 0;
2428 int nr_to_write_done = 0;
2429 struct pagevec pvec;
2430 int nr_pages;
2431 pgoff_t index;
2432 pgoff_t end; /* Inclusive */
2433 int scanned = 0;
2434 int tag;
2435
2436 pagevec_init(&pvec, 0);
2437 if (wbc->range_cyclic) {
2438 index = mapping->writeback_index; /* Start from prev offset */
2439 end = -1;
2440 } else {
2441 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2442 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2443 scanned = 1;
2444 }
2445 if (wbc->sync_mode == WB_SYNC_ALL)
2446 tag = PAGECACHE_TAG_TOWRITE;
2447 else
2448 tag = PAGECACHE_TAG_DIRTY;
2449 retry:
2450 if (wbc->sync_mode == WB_SYNC_ALL)
2451 tag_pages_for_writeback(mapping, index, end);
2452 while (!done && !nr_to_write_done && (index <= end) &&
2453 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2454 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2455 unsigned i;
2456
2457 scanned = 1;
2458 for (i = 0; i < nr_pages; i++) {
2459 struct page *page = pvec.pages[i];
2460
2461 /*
2462 * At this point we hold neither mapping->tree_lock nor
2463 * lock on the page itself: the page may be truncated or
2464 * invalidated (changing page->mapping to NULL), or even
2465 * swizzled back from swapper_space to tmpfs file
2466 * mapping
2467 */
2468 if (tree->ops && tree->ops->write_cache_pages_lock_hook)
2469 tree->ops->write_cache_pages_lock_hook(page);
2470 else
2471 lock_page(page);
2472
2473 if (unlikely(page->mapping != mapping)) {
2474 unlock_page(page);
2475 continue;
2476 }
2477
2478 if (!wbc->range_cyclic && page->index > end) {
2479 done = 1;
2480 unlock_page(page);
2481 continue;
2482 }
2483
2484 if (wbc->sync_mode != WB_SYNC_NONE) {
2485 if (PageWriteback(page))
2486 flush_fn(data);
2487 wait_on_page_writeback(page);
2488 }
2489
2490 if (PageWriteback(page) ||
2491 !clear_page_dirty_for_io(page)) {
2492 unlock_page(page);
2493 continue;
2494 }
2495
2496 ret = (*writepage)(page, wbc, data);
2497
2498 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
2499 unlock_page(page);
2500 ret = 0;
2501 }
2502 if (ret)
2503 done = 1;
2504
2505 /*
2506 * the filesystem may choose to bump up nr_to_write.
2507 * We have to make sure to honor the new nr_to_write
2508 * at any time
2509 */
2510 nr_to_write_done = wbc->nr_to_write <= 0;
2511 }
2512 pagevec_release(&pvec);
2513 cond_resched();
2514 }
2515 if (!scanned && !done) {
2516 /*
2517 * We hit the last page and there is more work to be done: wrap
2518 * back to the start of the file
2519 */
2520 scanned = 1;
2521 index = 0;
2522 goto retry;
2523 }
2524 return ret;
2525 }
2526
2527 static void flush_epd_write_bio(struct extent_page_data *epd)
2528 {
2529 if (epd->bio) {
2530 if (epd->sync_io)
2531 submit_one_bio(WRITE_SYNC, epd->bio, 0, 0);
2532 else
2533 submit_one_bio(WRITE, epd->bio, 0, 0);
2534 epd->bio = NULL;
2535 }
2536 }
2537
2538 static noinline void flush_write_bio(void *data)
2539 {
2540 struct extent_page_data *epd = data;
2541 flush_epd_write_bio(epd);
2542 }
2543
2544 int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
2545 get_extent_t *get_extent,
2546 struct writeback_control *wbc)
2547 {
2548 int ret;
2549 struct address_space *mapping = page->mapping;
2550 struct extent_page_data epd = {
2551 .bio = NULL,
2552 .tree = tree,
2553 .get_extent = get_extent,
2554 .extent_locked = 0,
2555 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2556 };
2557 struct writeback_control wbc_writepages = {
2558 .sync_mode = wbc->sync_mode,
2559 .nr_to_write = 64,
2560 .range_start = page_offset(page) + PAGE_CACHE_SIZE,
2561 .range_end = (loff_t)-1,
2562 };
2563
2564 ret = __extent_writepage(page, wbc, &epd);
2565
2566 extent_write_cache_pages(tree, mapping, &wbc_writepages,
2567 __extent_writepage, &epd, flush_write_bio);
2568 flush_epd_write_bio(&epd);
2569 return ret;
2570 }
2571
2572 int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
2573 u64 start, u64 end, get_extent_t *get_extent,
2574 int mode)
2575 {
2576 int ret = 0;
2577 struct address_space *mapping = inode->i_mapping;
2578 struct page *page;
2579 unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
2580 PAGE_CACHE_SHIFT;
2581
2582 struct extent_page_data epd = {
2583 .bio = NULL,
2584 .tree = tree,
2585 .get_extent = get_extent,
2586 .extent_locked = 1,
2587 .sync_io = mode == WB_SYNC_ALL,
2588 };
2589 struct writeback_control wbc_writepages = {
2590 .sync_mode = mode,
2591 .nr_to_write = nr_pages * 2,
2592 .range_start = start,
2593 .range_end = end + 1,
2594 };
2595
2596 while (start <= end) {
2597 page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
2598 if (clear_page_dirty_for_io(page))
2599 ret = __extent_writepage(page, &wbc_writepages, &epd);
2600 else {
2601 if (tree->ops && tree->ops->writepage_end_io_hook)
2602 tree->ops->writepage_end_io_hook(page, start,
2603 start + PAGE_CACHE_SIZE - 1,
2604 NULL, 1);
2605 unlock_page(page);
2606 }
2607 page_cache_release(page);
2608 start += PAGE_CACHE_SIZE;
2609 }
2610
2611 flush_epd_write_bio(&epd);
2612 return ret;
2613 }
2614
2615 int extent_writepages(struct extent_io_tree *tree,
2616 struct address_space *mapping,
2617 get_extent_t *get_extent,
2618 struct writeback_control *wbc)
2619 {
2620 int ret = 0;
2621 struct extent_page_data epd = {
2622 .bio = NULL,
2623 .tree = tree,
2624 .get_extent = get_extent,
2625 .extent_locked = 0,
2626 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
2627 };
2628
2629 ret = extent_write_cache_pages(tree, mapping, wbc,
2630 __extent_writepage, &epd,
2631 flush_write_bio);
2632 flush_epd_write_bio(&epd);
2633 return ret;
2634 }
2635
2636 int extent_readpages(struct extent_io_tree *tree,
2637 struct address_space *mapping,
2638 struct list_head *pages, unsigned nr_pages,
2639 get_extent_t get_extent)
2640 {
2641 struct bio *bio = NULL;
2642 unsigned page_idx;
2643 unsigned long bio_flags = 0;
2644
2645 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
2646 struct page *page = list_entry(pages->prev, struct page, lru);
2647
2648 prefetchw(&page->flags);
2649 list_del(&page->lru);
2650 if (!add_to_page_cache_lru(page, mapping,
2651 page->index, GFP_NOFS)) {
2652 __extent_read_full_page(tree, page, get_extent,
2653 &bio, 0, &bio_flags);
2654 }
2655 page_cache_release(page);
2656 }
2657 BUG_ON(!list_empty(pages));
2658 if (bio)
2659 submit_one_bio(READ, bio, 0, bio_flags);
2660 return 0;
2661 }
2662
2663 /*
2664 * basic invalidatepage code, this waits on any locked or writeback
2665 * ranges corresponding to the page, and then deletes any extent state
2666 * records from the tree
2667 */
2668 int extent_invalidatepage(struct extent_io_tree *tree,
2669 struct page *page, unsigned long offset)
2670 {
2671 struct extent_state *cached_state = NULL;
2672 u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
2673 u64 end = start + PAGE_CACHE_SIZE - 1;
2674 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
2675
2676 start += (offset + blocksize - 1) & ~(blocksize - 1);
2677 if (start > end)
2678 return 0;
2679
2680 lock_extent_bits(tree, start, end, 0, &cached_state, GFP_NOFS);
2681 wait_on_page_writeback(page);
2682 clear_extent_bit(tree, start, end,
2683 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
2684 EXTENT_DO_ACCOUNTING,
2685 1, 1, &cached_state, GFP_NOFS);
2686 return 0;
2687 }
2688
2689 /*
2690 * a helper for releasepage, this tests for areas of the page that
2691 * are locked or under IO and drops the related state bits if it is safe
2692 * to drop the page.
2693 */
2694 int try_release_extent_state(struct extent_map_tree *map,
2695 struct extent_io_tree *tree, struct page *page,
2696 gfp_t mask)
2697 {
2698 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2699 u64 end = start + PAGE_CACHE_SIZE - 1;
2700 int ret = 1;
2701
2702 if (test_range_bit(tree, start, end,
2703 EXTENT_IOBITS, 0, NULL))
2704 ret = 0;
2705 else {
2706 if ((mask & GFP_NOFS) == GFP_NOFS)
2707 mask = GFP_NOFS;
2708 /*
2709 * at this point we can safely clear everything except the
2710 * locked bit and the nodatasum bit
2711 */
2712 ret = clear_extent_bit(tree, start, end,
2713 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
2714 0, 0, NULL, mask);
2715
2716 /* if clear_extent_bit failed for enomem reasons,
2717 * we can't allow the release to continue.
2718 */
2719 if (ret < 0)
2720 ret = 0;
2721 else
2722 ret = 1;
2723 }
2724 return ret;
2725 }
2726
2727 /*
2728 * a helper for releasepage. As long as there are no locked extents
2729 * in the range corresponding to the page, both state records and extent
2730 * map records are removed
2731 */
2732 int try_release_extent_mapping(struct extent_map_tree *map,
2733 struct extent_io_tree *tree, struct page *page,
2734 gfp_t mask)
2735 {
2736 struct extent_map *em;
2737 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2738 u64 end = start + PAGE_CACHE_SIZE - 1;
2739
2740 if ((mask & __GFP_WAIT) &&
2741 page->mapping->host->i_size > 16 * 1024 * 1024) {
2742 u64 len;
2743 while (start <= end) {
2744 len = end - start + 1;
2745 write_lock(&map->lock);
2746 em = lookup_extent_mapping(map, start, len);
2747 if (IS_ERR_OR_NULL(em)) {
2748 write_unlock(&map->lock);
2749 break;
2750 }
2751 if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
2752 em->start != start) {
2753 write_unlock(&map->lock);
2754 free_extent_map(em);
2755 break;
2756 }
2757 if (!test_range_bit(tree, em->start,
2758 extent_map_end(em) - 1,
2759 EXTENT_LOCKED | EXTENT_WRITEBACK,
2760 0, NULL)) {
2761 remove_extent_mapping(map, em);
2762 /* once for the rb tree */
2763 free_extent_map(em);
2764 }
2765 start = extent_map_end(em);
2766 write_unlock(&map->lock);
2767
2768 /* once for us */
2769 free_extent_map(em);
2770 }
2771 }
2772 return try_release_extent_state(map, tree, page, mask);
2773 }
2774
2775 /*
2776 * helper function for fiemap, which doesn't want to see any holes.
2777 * This maps until we find something past 'last'
2778 */
2779 static struct extent_map *get_extent_skip_holes(struct inode *inode,
2780 u64 offset,
2781 u64 last,
2782 get_extent_t *get_extent)
2783 {
2784 u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
2785 struct extent_map *em;
2786 u64 len;
2787
2788 if (offset >= last)
2789 return NULL;
2790
2791 while(1) {
2792 len = last - offset;
2793 if (len == 0)
2794 break;
2795 len = (len + sectorsize - 1) & ~(sectorsize - 1);
2796 em = get_extent(inode, NULL, 0, offset, len, 0);
2797 if (IS_ERR_OR_NULL(em))
2798 return em;
2799
2800 /* if this isn't a hole return it */
2801 if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
2802 em->block_start != EXTENT_MAP_HOLE) {
2803 return em;
2804 }
2805
2806 /* this is a hole, advance to the next extent */
2807 offset = extent_map_end(em);
2808 free_extent_map(em);
2809 if (offset >= last)
2810 break;
2811 }
2812 return NULL;
2813 }
2814
2815 int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
2816 __u64 start, __u64 len, get_extent_t *get_extent)
2817 {
2818 int ret = 0;
2819 u64 off = start;
2820 u64 max = start + len;
2821 u32 flags = 0;
2822 u32 found_type;
2823 u64 last;
2824 u64 last_for_get_extent = 0;
2825 u64 disko = 0;
2826 u64 isize = i_size_read(inode);
2827 struct btrfs_key found_key;
2828 struct extent_map *em = NULL;
2829 struct extent_state *cached_state = NULL;
2830 struct btrfs_path *path;
2831 struct btrfs_file_extent_item *item;
2832 int end = 0;
2833 u64 em_start = 0;
2834 u64 em_len = 0;
2835 u64 em_end = 0;
2836 unsigned long emflags;
2837
2838 if (len == 0)
2839 return -EINVAL;
2840
2841 path = btrfs_alloc_path();
2842 if (!path)
2843 return -ENOMEM;
2844 path->leave_spinning = 1;
2845
2846 /*
2847 * lookup the last file extent. We're not using i_size here
2848 * because there might be preallocation past i_size
2849 */
2850 ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
2851 path, btrfs_ino(inode), -1, 0);
2852 if (ret < 0) {
2853 btrfs_free_path(path);
2854 return ret;
2855 }
2856 WARN_ON(!ret);
2857 path->slots[0]--;
2858 item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2859 struct btrfs_file_extent_item);
2860 btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
2861 found_type = btrfs_key_type(&found_key);
2862
2863 /* No extents, but there might be delalloc bits */
2864 if (found_key.objectid != btrfs_ino(inode) ||
2865 found_type != BTRFS_EXTENT_DATA_KEY) {
2866 /* have to trust i_size as the end */
2867 last = (u64)-1;
2868 last_for_get_extent = isize;
2869 } else {
2870 /*
2871 * remember the start of the last extent. There are a
2872 * bunch of different factors that go into the length of the
2873 * extent, so its much less complex to remember where it started
2874 */
2875 last = found_key.offset;
2876 last_for_get_extent = last + 1;
2877 }
2878 btrfs_free_path(path);
2879
2880 /*
2881 * we might have some extents allocated but more delalloc past those
2882 * extents. so, we trust isize unless the start of the last extent is
2883 * beyond isize
2884 */
2885 if (last < isize) {
2886 last = (u64)-1;
2887 last_for_get_extent = isize;
2888 }
2889
2890 lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
2891 &cached_state, GFP_NOFS);
2892
2893 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2894 get_extent);
2895 if (!em)
2896 goto out;
2897 if (IS_ERR(em)) {
2898 ret = PTR_ERR(em);
2899 goto out;
2900 }
2901
2902 while (!end) {
2903 u64 offset_in_extent;
2904
2905 /* break if the extent we found is outside the range */
2906 if (em->start >= max || extent_map_end(em) < off)
2907 break;
2908
2909 /*
2910 * get_extent may return an extent that starts before our
2911 * requested range. We have to make sure the ranges
2912 * we return to fiemap always move forward and don't
2913 * overlap, so adjust the offsets here
2914 */
2915 em_start = max(em->start, off);
2916
2917 /*
2918 * record the offset from the start of the extent
2919 * for adjusting the disk offset below
2920 */
2921 offset_in_extent = em_start - em->start;
2922 em_end = extent_map_end(em);
2923 em_len = em_end - em_start;
2924 emflags = em->flags;
2925 disko = 0;
2926 flags = 0;
2927
2928 /*
2929 * bump off for our next call to get_extent
2930 */
2931 off = extent_map_end(em);
2932 if (off >= max)
2933 end = 1;
2934
2935 if (em->block_start == EXTENT_MAP_LAST_BYTE) {
2936 end = 1;
2937 flags |= FIEMAP_EXTENT_LAST;
2938 } else if (em->block_start == EXTENT_MAP_INLINE) {
2939 flags |= (FIEMAP_EXTENT_DATA_INLINE |
2940 FIEMAP_EXTENT_NOT_ALIGNED);
2941 } else if (em->block_start == EXTENT_MAP_DELALLOC) {
2942 flags |= (FIEMAP_EXTENT_DELALLOC |
2943 FIEMAP_EXTENT_UNKNOWN);
2944 } else {
2945 disko = em->block_start + offset_in_extent;
2946 }
2947 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
2948 flags |= FIEMAP_EXTENT_ENCODED;
2949
2950 free_extent_map(em);
2951 em = NULL;
2952 if ((em_start >= last) || em_len == (u64)-1 ||
2953 (last == (u64)-1 && isize <= em_end)) {
2954 flags |= FIEMAP_EXTENT_LAST;
2955 end = 1;
2956 }
2957
2958 /* now scan forward to see if this is really the last extent. */
2959 em = get_extent_skip_holes(inode, off, last_for_get_extent,
2960 get_extent);
2961 if (IS_ERR(em)) {
2962 ret = PTR_ERR(em);
2963 goto out;
2964 }
2965 if (!em) {
2966 flags |= FIEMAP_EXTENT_LAST;
2967 end = 1;
2968 }
2969 ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
2970 em_len, flags);
2971 if (ret)
2972 goto out_free;
2973 }
2974 out_free:
2975 free_extent_map(em);
2976 out:
2977 unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len,
2978 &cached_state, GFP_NOFS);
2979 return ret;
2980 }
2981
2982 static inline struct page *extent_buffer_page(struct extent_buffer *eb,
2983 unsigned long i)
2984 {
2985 struct page *p;
2986 struct address_space *mapping;
2987
2988 if (i == 0)
2989 return eb->first_page;
2990 i += eb->start >> PAGE_CACHE_SHIFT;
2991 mapping = eb->first_page->mapping;
2992 if (!mapping)
2993 return NULL;
2994
2995 /*
2996 * extent_buffer_page is only called after pinning the page
2997 * by increasing the reference count. So we know the page must
2998 * be in the radix tree.
2999 */
3000 rcu_read_lock();
3001 p = radix_tree_lookup(&mapping->page_tree, i);
3002 rcu_read_unlock();
3003
3004 return p;
3005 }
3006
3007 static inline unsigned long num_extent_pages(u64 start, u64 len)
3008 {
3009 return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
3010 (start >> PAGE_CACHE_SHIFT);
3011 }
3012
3013 static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
3014 u64 start,
3015 unsigned long len,
3016 gfp_t mask)
3017 {
3018 struct extent_buffer *eb = NULL;
3019 #if LEAK_DEBUG
3020 unsigned long flags;
3021 #endif
3022
3023 eb = kmem_cache_zalloc(extent_buffer_cache, mask);
3024 if (eb == NULL)
3025 return NULL;
3026 eb->start = start;
3027 eb->len = len;
3028 rwlock_init(&eb->lock);
3029 atomic_set(&eb->write_locks, 0);
3030 atomic_set(&eb->read_locks, 0);
3031 atomic_set(&eb->blocking_readers, 0);
3032 atomic_set(&eb->blocking_writers, 0);
3033 atomic_set(&eb->spinning_readers, 0);
3034 atomic_set(&eb->spinning_writers, 0);
3035 init_waitqueue_head(&eb->write_lock_wq);
3036 init_waitqueue_head(&eb->read_lock_wq);
3037
3038 #if LEAK_DEBUG
3039 spin_lock_irqsave(&leak_lock, flags);
3040 list_add(&eb->leak_list, &buffers);
3041 spin_unlock_irqrestore(&leak_lock, flags);
3042 #endif
3043 atomic_set(&eb->refs, 1);
3044
3045 return eb;
3046 }
3047
3048 static void __free_extent_buffer(struct extent_buffer *eb)
3049 {
3050 #if LEAK_DEBUG
3051 unsigned long flags;
3052 spin_lock_irqsave(&leak_lock, flags);
3053 list_del(&eb->leak_list);
3054 spin_unlock_irqrestore(&leak_lock, flags);
3055 #endif
3056 kmem_cache_free(extent_buffer_cache, eb);
3057 }
3058
3059 /*
3060 * Helper for releasing extent buffer page.
3061 */
3062 static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
3063 unsigned long start_idx)
3064 {
3065 unsigned long index;
3066 struct page *page;
3067
3068 if (!eb->first_page)
3069 return;
3070
3071 index = num_extent_pages(eb->start, eb->len);
3072 if (start_idx >= index)
3073 return;
3074
3075 do {
3076 index--;
3077 page = extent_buffer_page(eb, index);
3078 if (page)
3079 page_cache_release(page);
3080 } while (index != start_idx);
3081 }
3082
3083 /*
3084 * Helper for releasing the extent buffer.
3085 */
3086 static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
3087 {
3088 btrfs_release_extent_buffer_page(eb, 0);
3089 __free_extent_buffer(eb);
3090 }
3091
3092 struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
3093 u64 start, unsigned long len,
3094 struct page *page0)
3095 {
3096 unsigned long num_pages = num_extent_pages(start, len);
3097 unsigned long i;
3098 unsigned long index = start >> PAGE_CACHE_SHIFT;
3099 struct extent_buffer *eb;
3100 struct extent_buffer *exists = NULL;
3101 struct page *p;
3102 struct address_space *mapping = tree->mapping;
3103 int uptodate = 1;
3104 int ret;
3105
3106 rcu_read_lock();
3107 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3108 if (eb && atomic_inc_not_zero(&eb->refs)) {
3109 rcu_read_unlock();
3110 mark_page_accessed(eb->first_page);
3111 return eb;
3112 }
3113 rcu_read_unlock();
3114
3115 eb = __alloc_extent_buffer(tree, start, len, GFP_NOFS);
3116 if (!eb)
3117 return NULL;
3118
3119 if (page0) {
3120 eb->first_page = page0;
3121 i = 1;
3122 index++;
3123 page_cache_get(page0);
3124 mark_page_accessed(page0);
3125 set_page_extent_mapped(page0);
3126 set_page_extent_head(page0, len);
3127 uptodate = PageUptodate(page0);
3128 } else {
3129 i = 0;
3130 }
3131 for (; i < num_pages; i++, index++) {
3132 p = find_or_create_page(mapping, index, GFP_NOFS);
3133 if (!p) {
3134 WARN_ON(1);
3135 goto free_eb;
3136 }
3137 set_page_extent_mapped(p);
3138 mark_page_accessed(p);
3139 if (i == 0) {
3140 eb->first_page = p;
3141 set_page_extent_head(p, len);
3142 } else {
3143 set_page_private(p, EXTENT_PAGE_PRIVATE);
3144 }
3145 if (!PageUptodate(p))
3146 uptodate = 0;
3147
3148 /*
3149 * see below about how we avoid a nasty race with release page
3150 * and why we unlock later
3151 */
3152 if (i != 0)
3153 unlock_page(p);
3154 }
3155 if (uptodate)
3156 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3157
3158 ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
3159 if (ret)
3160 goto free_eb;
3161
3162 spin_lock(&tree->buffer_lock);
3163 ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
3164 if (ret == -EEXIST) {
3165 exists = radix_tree_lookup(&tree->buffer,
3166 start >> PAGE_CACHE_SHIFT);
3167 /* add one reference for the caller */
3168 atomic_inc(&exists->refs);
3169 spin_unlock(&tree->buffer_lock);
3170 radix_tree_preload_end();
3171 goto free_eb;
3172 }
3173 /* add one reference for the tree */
3174 atomic_inc(&eb->refs);
3175 spin_unlock(&tree->buffer_lock);
3176 radix_tree_preload_end();
3177
3178 /*
3179 * there is a race where release page may have
3180 * tried to find this extent buffer in the radix
3181 * but failed. It will tell the VM it is safe to
3182 * reclaim the, and it will clear the page private bit.
3183 * We must make sure to set the page private bit properly
3184 * after the extent buffer is in the radix tree so
3185 * it doesn't get lost
3186 */
3187 set_page_extent_mapped(eb->first_page);
3188 set_page_extent_head(eb->first_page, eb->len);
3189 if (!page0)
3190 unlock_page(eb->first_page);
3191 return eb;
3192
3193 free_eb:
3194 if (eb->first_page && !page0)
3195 unlock_page(eb->first_page);
3196
3197 if (!atomic_dec_and_test(&eb->refs))
3198 return exists;
3199 btrfs_release_extent_buffer(eb);
3200 return exists;
3201 }
3202
3203 struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
3204 u64 start, unsigned long len)
3205 {
3206 struct extent_buffer *eb;
3207
3208 rcu_read_lock();
3209 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3210 if (eb && atomic_inc_not_zero(&eb->refs)) {
3211 rcu_read_unlock();
3212 mark_page_accessed(eb->first_page);
3213 return eb;
3214 }
3215 rcu_read_unlock();
3216
3217 return NULL;
3218 }
3219
3220 void free_extent_buffer(struct extent_buffer *eb)
3221 {
3222 if (!eb)
3223 return;
3224
3225 if (!atomic_dec_and_test(&eb->refs))
3226 return;
3227
3228 WARN_ON(1);
3229 }
3230
3231 int clear_extent_buffer_dirty(struct extent_io_tree *tree,
3232 struct extent_buffer *eb)
3233 {
3234 unsigned long i;
3235 unsigned long num_pages;
3236 struct page *page;
3237
3238 num_pages = num_extent_pages(eb->start, eb->len);
3239
3240 for (i = 0; i < num_pages; i++) {
3241 page = extent_buffer_page(eb, i);
3242 if (!PageDirty(page))
3243 continue;
3244
3245 lock_page(page);
3246 WARN_ON(!PagePrivate(page));
3247
3248 set_page_extent_mapped(page);
3249 if (i == 0)
3250 set_page_extent_head(page, eb->len);
3251
3252 clear_page_dirty_for_io(page);
3253 spin_lock_irq(&page->mapping->tree_lock);
3254 if (!PageDirty(page)) {
3255 radix_tree_tag_clear(&page->mapping->page_tree,
3256 page_index(page),
3257 PAGECACHE_TAG_DIRTY);
3258 }
3259 spin_unlock_irq(&page->mapping->tree_lock);
3260 unlock_page(page);
3261 }
3262 return 0;
3263 }
3264
3265 int set_extent_buffer_dirty(struct extent_io_tree *tree,
3266 struct extent_buffer *eb)
3267 {
3268 unsigned long i;
3269 unsigned long num_pages;
3270 int was_dirty = 0;
3271
3272 was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
3273 num_pages = num_extent_pages(eb->start, eb->len);
3274 for (i = 0; i < num_pages; i++)
3275 __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3276 return was_dirty;
3277 }
3278
3279 static int __eb_straddles_pages(u64 start, u64 len)
3280 {
3281 if (len < PAGE_CACHE_SIZE)
3282 return 1;
3283 if (start & (PAGE_CACHE_SIZE - 1))
3284 return 1;
3285 if ((start + len) & (PAGE_CACHE_SIZE - 1))
3286 return 1;
3287 return 0;
3288 }
3289
3290 static int eb_straddles_pages(struct extent_buffer *eb)
3291 {
3292 return __eb_straddles_pages(eb->start, eb->len);
3293 }
3294
3295 int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3296 struct extent_buffer *eb,
3297 struct extent_state **cached_state)
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 clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3305
3306 if (eb_straddles_pages(eb)) {
3307 clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3308 cached_state, GFP_NOFS);
3309 }
3310 for (i = 0; i < num_pages; i++) {
3311 page = extent_buffer_page(eb, i);
3312 if (page)
3313 ClearPageUptodate(page);
3314 }
3315 return 0;
3316 }
3317
3318 int set_extent_buffer_uptodate(struct extent_io_tree *tree,
3319 struct extent_buffer *eb)
3320 {
3321 unsigned long i;
3322 struct page *page;
3323 unsigned long num_pages;
3324
3325 num_pages = num_extent_pages(eb->start, eb->len);
3326
3327 if (eb_straddles_pages(eb)) {
3328 set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3329 NULL, GFP_NOFS);
3330 }
3331 for (i = 0; i < num_pages; i++) {
3332 page = extent_buffer_page(eb, i);
3333 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3334 ((i == num_pages - 1) &&
3335 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3336 check_page_uptodate(tree, page);
3337 continue;
3338 }
3339 SetPageUptodate(page);
3340 }
3341 return 0;
3342 }
3343
3344 int extent_range_uptodate(struct extent_io_tree *tree,
3345 u64 start, u64 end)
3346 {
3347 struct page *page;
3348 int ret;
3349 int pg_uptodate = 1;
3350 int uptodate;
3351 unsigned long index;
3352
3353 if (__eb_straddles_pages(start, end - start + 1)) {
3354 ret = test_range_bit(tree, start, end,
3355 EXTENT_UPTODATE, 1, NULL);
3356 if (ret)
3357 return 1;
3358 }
3359 while (start <= end) {
3360 index = start >> PAGE_CACHE_SHIFT;
3361 page = find_get_page(tree->mapping, index);
3362 uptodate = PageUptodate(page);
3363 page_cache_release(page);
3364 if (!uptodate) {
3365 pg_uptodate = 0;
3366 break;
3367 }
3368 start += PAGE_CACHE_SIZE;
3369 }
3370 return pg_uptodate;
3371 }
3372
3373 int extent_buffer_uptodate(struct extent_io_tree *tree,
3374 struct extent_buffer *eb,
3375 struct extent_state *cached_state)
3376 {
3377 int ret = 0;
3378 unsigned long num_pages;
3379 unsigned long i;
3380 struct page *page;
3381 int pg_uptodate = 1;
3382
3383 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3384 return 1;
3385
3386 if (eb_straddles_pages(eb)) {
3387 ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3388 EXTENT_UPTODATE, 1, cached_state);
3389 if (ret)
3390 return ret;
3391 }
3392
3393 num_pages = num_extent_pages(eb->start, eb->len);
3394 for (i = 0; i < num_pages; i++) {
3395 page = extent_buffer_page(eb, i);
3396 if (!PageUptodate(page)) {
3397 pg_uptodate = 0;
3398 break;
3399 }
3400 }
3401 return pg_uptodate;
3402 }
3403
3404 int read_extent_buffer_pages(struct extent_io_tree *tree,
3405 struct extent_buffer *eb,
3406 u64 start, int wait,
3407 get_extent_t *get_extent, int mirror_num)
3408 {
3409 unsigned long i;
3410 unsigned long start_i;
3411 struct page *page;
3412 int err;
3413 int ret = 0;
3414 int locked_pages = 0;
3415 int all_uptodate = 1;
3416 int inc_all_pages = 0;
3417 unsigned long num_pages;
3418 struct bio *bio = NULL;
3419 unsigned long bio_flags = 0;
3420
3421 if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3422 return 0;
3423
3424 if (eb_straddles_pages(eb)) {
3425 if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3426 EXTENT_UPTODATE, 1, NULL)) {
3427 return 0;
3428 }
3429 }
3430
3431 if (start) {
3432 WARN_ON(start < eb->start);
3433 start_i = (start >> PAGE_CACHE_SHIFT) -
3434 (eb->start >> PAGE_CACHE_SHIFT);
3435 } else {
3436 start_i = 0;
3437 }
3438
3439 num_pages = num_extent_pages(eb->start, eb->len);
3440 for (i = start_i; i < num_pages; i++) {
3441 page = extent_buffer_page(eb, i);
3442 if (!wait) {
3443 if (!trylock_page(page))
3444 goto unlock_exit;
3445 } else {
3446 lock_page(page);
3447 }
3448 locked_pages++;
3449 if (!PageUptodate(page))
3450 all_uptodate = 0;
3451 }
3452 if (all_uptodate) {
3453 if (start_i == 0)
3454 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3455 goto unlock_exit;
3456 }
3457
3458 for (i = start_i; i < num_pages; i++) {
3459 page = extent_buffer_page(eb, i);
3460
3461 WARN_ON(!PagePrivate(page));
3462
3463 set_page_extent_mapped(page);
3464 if (i == 0)
3465 set_page_extent_head(page, eb->len);
3466
3467 if (inc_all_pages)
3468 page_cache_get(page);
3469 if (!PageUptodate(page)) {
3470 if (start_i == 0)
3471 inc_all_pages = 1;
3472 ClearPageError(page);
3473 err = __extent_read_full_page(tree, page,
3474 get_extent, &bio,
3475 mirror_num, &bio_flags);
3476 if (err)
3477 ret = err;
3478 } else {
3479 unlock_page(page);
3480 }
3481 }
3482
3483 if (bio)
3484 submit_one_bio(READ, bio, mirror_num, bio_flags);
3485
3486 if (ret || !wait)
3487 return ret;
3488
3489 for (i = start_i; i < num_pages; i++) {
3490 page = extent_buffer_page(eb, i);
3491 wait_on_page_locked(page);
3492 if (!PageUptodate(page))
3493 ret = -EIO;
3494 }
3495
3496 if (!ret)
3497 set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3498 return ret;
3499
3500 unlock_exit:
3501 i = start_i;
3502 while (locked_pages > 0) {
3503 page = extent_buffer_page(eb, i);
3504 i++;
3505 unlock_page(page);
3506 locked_pages--;
3507 }
3508 return ret;
3509 }
3510
3511 void read_extent_buffer(struct extent_buffer *eb, void *dstv,
3512 unsigned long start,
3513 unsigned long len)
3514 {
3515 size_t cur;
3516 size_t offset;
3517 struct page *page;
3518 char *kaddr;
3519 char *dst = (char *)dstv;
3520 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3521 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3522
3523 WARN_ON(start > eb->len);
3524 WARN_ON(start + len > eb->start + eb->len);
3525
3526 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3527
3528 while (len > 0) {
3529 page = extent_buffer_page(eb, i);
3530
3531 cur = min(len, (PAGE_CACHE_SIZE - offset));
3532 kaddr = page_address(page);
3533 memcpy(dst, kaddr + offset, cur);
3534
3535 dst += cur;
3536 len -= cur;
3537 offset = 0;
3538 i++;
3539 }
3540 }
3541
3542 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
3543 unsigned long min_len, char **map,
3544 unsigned long *map_start,
3545 unsigned long *map_len)
3546 {
3547 size_t offset = start & (PAGE_CACHE_SIZE - 1);
3548 char *kaddr;
3549 struct page *p;
3550 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3551 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3552 unsigned long end_i = (start_offset + start + min_len - 1) >>
3553 PAGE_CACHE_SHIFT;
3554
3555 if (i != end_i)
3556 return -EINVAL;
3557
3558 if (i == 0) {
3559 offset = start_offset;
3560 *map_start = 0;
3561 } else {
3562 offset = 0;
3563 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
3564 }
3565
3566 if (start + min_len > eb->len) {
3567 printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
3568 "wanted %lu %lu\n", (unsigned long long)eb->start,
3569 eb->len, start, min_len);
3570 WARN_ON(1);
3571 return -EINVAL;
3572 }
3573
3574 p = extent_buffer_page(eb, i);
3575 kaddr = page_address(p);
3576 *map = kaddr + offset;
3577 *map_len = PAGE_CACHE_SIZE - offset;
3578 return 0;
3579 }
3580
3581 int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
3582 unsigned long start,
3583 unsigned long len)
3584 {
3585 size_t cur;
3586 size_t offset;
3587 struct page *page;
3588 char *kaddr;
3589 char *ptr = (char *)ptrv;
3590 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3591 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3592 int ret = 0;
3593
3594 WARN_ON(start > eb->len);
3595 WARN_ON(start + len > eb->start + eb->len);
3596
3597 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3598
3599 while (len > 0) {
3600 page = extent_buffer_page(eb, i);
3601
3602 cur = min(len, (PAGE_CACHE_SIZE - offset));
3603
3604 kaddr = page_address(page);
3605 ret = memcmp(ptr, kaddr + offset, cur);
3606 if (ret)
3607 break;
3608
3609 ptr += cur;
3610 len -= cur;
3611 offset = 0;
3612 i++;
3613 }
3614 return ret;
3615 }
3616
3617 void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
3618 unsigned long start, unsigned long len)
3619 {
3620 size_t cur;
3621 size_t offset;
3622 struct page *page;
3623 char *kaddr;
3624 char *src = (char *)srcv;
3625 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3626 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3627
3628 WARN_ON(start > eb->len);
3629 WARN_ON(start + len > eb->start + eb->len);
3630
3631 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3632
3633 while (len > 0) {
3634 page = extent_buffer_page(eb, i);
3635 WARN_ON(!PageUptodate(page));
3636
3637 cur = min(len, PAGE_CACHE_SIZE - offset);
3638 kaddr = page_address(page);
3639 memcpy(kaddr + offset, src, cur);
3640
3641 src += cur;
3642 len -= cur;
3643 offset = 0;
3644 i++;
3645 }
3646 }
3647
3648 void memset_extent_buffer(struct extent_buffer *eb, char c,
3649 unsigned long start, unsigned long len)
3650 {
3651 size_t cur;
3652 size_t offset;
3653 struct page *page;
3654 char *kaddr;
3655 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3656 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3657
3658 WARN_ON(start > eb->len);
3659 WARN_ON(start + len > eb->start + eb->len);
3660
3661 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3662
3663 while (len > 0) {
3664 page = extent_buffer_page(eb, i);
3665 WARN_ON(!PageUptodate(page));
3666
3667 cur = min(len, PAGE_CACHE_SIZE - offset);
3668 kaddr = page_address(page);
3669 memset(kaddr + offset, c, cur);
3670
3671 len -= cur;
3672 offset = 0;
3673 i++;
3674 }
3675 }
3676
3677 void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
3678 unsigned long dst_offset, unsigned long src_offset,
3679 unsigned long len)
3680 {
3681 u64 dst_len = dst->len;
3682 size_t cur;
3683 size_t offset;
3684 struct page *page;
3685 char *kaddr;
3686 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3687 unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3688
3689 WARN_ON(src->len != dst_len);
3690
3691 offset = (start_offset + dst_offset) &
3692 ((unsigned long)PAGE_CACHE_SIZE - 1);
3693
3694 while (len > 0) {
3695 page = extent_buffer_page(dst, i);
3696 WARN_ON(!PageUptodate(page));
3697
3698 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
3699
3700 kaddr = page_address(page);
3701 read_extent_buffer(src, kaddr + offset, src_offset, cur);
3702
3703 src_offset += cur;
3704 len -= cur;
3705 offset = 0;
3706 i++;
3707 }
3708 }
3709
3710 static void move_pages(struct page *dst_page, struct page *src_page,
3711 unsigned long dst_off, unsigned long src_off,
3712 unsigned long len)
3713 {
3714 char *dst_kaddr = page_address(dst_page);
3715 if (dst_page == src_page) {
3716 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
3717 } else {
3718 char *src_kaddr = page_address(src_page);
3719 char *p = dst_kaddr + dst_off + len;
3720 char *s = src_kaddr + src_off + len;
3721
3722 while (len--)
3723 *--p = *--s;
3724 }
3725 }
3726
3727 static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
3728 {
3729 unsigned long distance = (src > dst) ? src - dst : dst - src;
3730 return distance < len;
3731 }
3732
3733 static void copy_pages(struct page *dst_page, struct page *src_page,
3734 unsigned long dst_off, unsigned long src_off,
3735 unsigned long len)
3736 {
3737 char *dst_kaddr = page_address(dst_page);
3738 char *src_kaddr;
3739
3740 if (dst_page != src_page) {
3741 src_kaddr = page_address(src_page);
3742 } else {
3743 src_kaddr = dst_kaddr;
3744 BUG_ON(areas_overlap(src_off, dst_off, len));
3745 }
3746
3747 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
3748 }
3749
3750 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3751 unsigned long src_offset, unsigned long len)
3752 {
3753 size_t cur;
3754 size_t dst_off_in_page;
3755 size_t src_off_in_page;
3756 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3757 unsigned long dst_i;
3758 unsigned long src_i;
3759
3760 if (src_offset + len > dst->len) {
3761 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3762 "len %lu dst len %lu\n", src_offset, len, dst->len);
3763 BUG_ON(1);
3764 }
3765 if (dst_offset + len > dst->len) {
3766 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3767 "len %lu dst len %lu\n", dst_offset, len, dst->len);
3768 BUG_ON(1);
3769 }
3770
3771 while (len > 0) {
3772 dst_off_in_page = (start_offset + dst_offset) &
3773 ((unsigned long)PAGE_CACHE_SIZE - 1);
3774 src_off_in_page = (start_offset + src_offset) &
3775 ((unsigned long)PAGE_CACHE_SIZE - 1);
3776
3777 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3778 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
3779
3780 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
3781 src_off_in_page));
3782 cur = min_t(unsigned long, cur,
3783 (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
3784
3785 copy_pages(extent_buffer_page(dst, dst_i),
3786 extent_buffer_page(dst, src_i),
3787 dst_off_in_page, src_off_in_page, cur);
3788
3789 src_offset += cur;
3790 dst_offset += cur;
3791 len -= cur;
3792 }
3793 }
3794
3795 void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3796 unsigned long src_offset, unsigned long len)
3797 {
3798 size_t cur;
3799 size_t dst_off_in_page;
3800 size_t src_off_in_page;
3801 unsigned long dst_end = dst_offset + len - 1;
3802 unsigned long src_end = src_offset + len - 1;
3803 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3804 unsigned long dst_i;
3805 unsigned long src_i;
3806
3807 if (src_offset + len > dst->len) {
3808 printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
3809 "len %lu len %lu\n", src_offset, len, dst->len);
3810 BUG_ON(1);
3811 }
3812 if (dst_offset + len > dst->len) {
3813 printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
3814 "len %lu len %lu\n", dst_offset, len, dst->len);
3815 BUG_ON(1);
3816 }
3817 if (!areas_overlap(src_offset, dst_offset, len)) {
3818 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
3819 return;
3820 }
3821 while (len > 0) {
3822 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
3823 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
3824
3825 dst_off_in_page = (start_offset + dst_end) &
3826 ((unsigned long)PAGE_CACHE_SIZE - 1);
3827 src_off_in_page = (start_offset + src_end) &
3828 ((unsigned long)PAGE_CACHE_SIZE - 1);
3829
3830 cur = min_t(unsigned long, len, src_off_in_page + 1);
3831 cur = min(cur, dst_off_in_page + 1);
3832 move_pages(extent_buffer_page(dst, dst_i),
3833 extent_buffer_page(dst, src_i),
3834 dst_off_in_page - cur + 1,
3835 src_off_in_page - cur + 1, cur);
3836
3837 dst_end -= cur;
3838 src_end -= cur;
3839 len -= cur;
3840 }
3841 }
3842
3843 static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
3844 {
3845 struct extent_buffer *eb =
3846 container_of(head, struct extent_buffer, rcu_head);
3847
3848 btrfs_release_extent_buffer(eb);
3849 }
3850
3851 int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
3852 {
3853 u64 start = page_offset(page);
3854 struct extent_buffer *eb;
3855 int ret = 1;
3856
3857 spin_lock(&tree->buffer_lock);
3858 eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3859 if (!eb) {
3860 spin_unlock(&tree->buffer_lock);
3861 return ret;
3862 }
3863
3864 if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3865 ret = 0;
3866 goto out;
3867 }
3868
3869 /*
3870 * set @eb->refs to 0 if it is already 1, and then release the @eb.
3871 * Or go back.
3872 */
3873 if (atomic_cmpxchg(&eb->refs, 1, 0) != 1) {
3874 ret = 0;
3875 goto out;
3876 }
3877
3878 radix_tree_delete(&tree->buffer, start >> PAGE_CACHE_SHIFT);
3879 out:
3880 spin_unlock(&tree->buffer_lock);
3881
3882 /* at this point we can safely release the extent buffer */
3883 if (atomic_read(&eb->refs) == 0)
3884 call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
3885 return ret;
3886 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree