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Btrfs: Use async helpers to deal with pages that have been improperly dirtied
[deliverable/linux.git] / fs / btrfs / extent_io.c
1 #include <linux/bitops.h>
2 #include <linux/slab.h>
3 #include <linux/bio.h>
4 #include <linux/mm.h>
5 #include <linux/gfp.h>
6 #include <linux/pagemap.h>
7 #include <linux/page-flags.h>
8 #include <linux/module.h>
9 #include <linux/spinlock.h>
10 #include <linux/blkdev.h>
11 #include <linux/swap.h>
12 #include <linux/version.h>
13 #include <linux/writeback.h>
14 #include <linux/pagevec.h>
15 #include "extent_io.h"
16 #include "extent_map.h"
17
18 /* temporary define until extent_map moves out of btrfs */
19 struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
20 unsigned long extra_flags,
21 void (*ctor)(void *, struct kmem_cache *,
22 unsigned long));
23
24 static struct kmem_cache *extent_state_cache;
25 static struct kmem_cache *extent_buffer_cache;
26
27 static LIST_HEAD(buffers);
28 static LIST_HEAD(states);
29 static spinlock_t leak_lock = SPIN_LOCK_UNLOCKED;
30
31 #define BUFFER_LRU_MAX 64
32
33 struct tree_entry {
34 u64 start;
35 u64 end;
36 struct rb_node rb_node;
37 };
38
39 struct extent_page_data {
40 struct bio *bio;
41 struct extent_io_tree *tree;
42 get_extent_t *get_extent;
43 };
44
45 int __init extent_io_init(void)
46 {
47 extent_state_cache = btrfs_cache_create("extent_state",
48 sizeof(struct extent_state), 0,
49 NULL);
50 if (!extent_state_cache)
51 return -ENOMEM;
52
53 extent_buffer_cache = btrfs_cache_create("extent_buffers",
54 sizeof(struct extent_buffer), 0,
55 NULL);
56 if (!extent_buffer_cache)
57 goto free_state_cache;
58 return 0;
59
60 free_state_cache:
61 kmem_cache_destroy(extent_state_cache);
62 return -ENOMEM;
63 }
64
65 void extent_io_exit(void)
66 {
67 struct extent_state *state;
68 struct extent_buffer *eb;
69
70 while (!list_empty(&states)) {
71 state = list_entry(states.next, struct extent_state, leak_list);
72 printk("state leak: start %Lu end %Lu state %lu in tree %p refs %d\n", state->start, state->end, state->state, state->tree, atomic_read(&state->refs));
73 list_del(&state->leak_list);
74 kmem_cache_free(extent_state_cache, state);
75
76 }
77
78 while (!list_empty(&buffers)) {
79 eb = list_entry(buffers.next, struct extent_buffer, leak_list);
80 printk("buffer leak start %Lu len %lu refs %d\n", eb->start, eb->len, atomic_read(&eb->refs));
81 list_del(&eb->leak_list);
82 kmem_cache_free(extent_buffer_cache, eb);
83 }
84 if (extent_state_cache)
85 kmem_cache_destroy(extent_state_cache);
86 if (extent_buffer_cache)
87 kmem_cache_destroy(extent_buffer_cache);
88 }
89
90 void extent_io_tree_init(struct extent_io_tree *tree,
91 struct address_space *mapping, gfp_t mask)
92 {
93 tree->state.rb_node = NULL;
94 tree->ops = NULL;
95 tree->dirty_bytes = 0;
96 spin_lock_init(&tree->lock);
97 spin_lock_init(&tree->lru_lock);
98 tree->mapping = mapping;
99 INIT_LIST_HEAD(&tree->buffer_lru);
100 tree->lru_size = 0;
101 tree->last = NULL;
102 }
103 EXPORT_SYMBOL(extent_io_tree_init);
104
105 void extent_io_tree_empty_lru(struct extent_io_tree *tree)
106 {
107 struct extent_buffer *eb;
108 while(!list_empty(&tree->buffer_lru)) {
109 eb = list_entry(tree->buffer_lru.next, struct extent_buffer,
110 lru);
111 list_del_init(&eb->lru);
112 free_extent_buffer(eb);
113 }
114 }
115 EXPORT_SYMBOL(extent_io_tree_empty_lru);
116
117 struct extent_state *alloc_extent_state(gfp_t mask)
118 {
119 struct extent_state *state;
120 unsigned long flags;
121
122 state = kmem_cache_alloc(extent_state_cache, mask);
123 if (!state)
124 return state;
125 state->state = 0;
126 state->private = 0;
127 state->tree = NULL;
128 spin_lock_irqsave(&leak_lock, flags);
129 list_add(&state->leak_list, &states);
130 spin_unlock_irqrestore(&leak_lock, flags);
131
132 atomic_set(&state->refs, 1);
133 init_waitqueue_head(&state->wq);
134 return state;
135 }
136 EXPORT_SYMBOL(alloc_extent_state);
137
138 void free_extent_state(struct extent_state *state)
139 {
140 if (!state)
141 return;
142 if (atomic_dec_and_test(&state->refs)) {
143 unsigned long flags;
144 WARN_ON(state->tree);
145 spin_lock_irqsave(&leak_lock, flags);
146 list_del(&state->leak_list);
147 spin_unlock_irqrestore(&leak_lock, flags);
148 kmem_cache_free(extent_state_cache, state);
149 }
150 }
151 EXPORT_SYMBOL(free_extent_state);
152
153 static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
154 struct rb_node *node)
155 {
156 struct rb_node ** p = &root->rb_node;
157 struct rb_node * parent = NULL;
158 struct tree_entry *entry;
159
160 while(*p) {
161 parent = *p;
162 entry = rb_entry(parent, struct tree_entry, rb_node);
163
164 if (offset < entry->start)
165 p = &(*p)->rb_left;
166 else if (offset > entry->end)
167 p = &(*p)->rb_right;
168 else
169 return parent;
170 }
171
172 entry = rb_entry(node, struct tree_entry, rb_node);
173 rb_link_node(node, parent, p);
174 rb_insert_color(node, root);
175 return NULL;
176 }
177
178 static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
179 struct rb_node **prev_ret,
180 struct rb_node **next_ret)
181 {
182 struct rb_root *root = &tree->state;
183 struct rb_node * n = root->rb_node;
184 struct rb_node *prev = NULL;
185 struct rb_node *orig_prev = NULL;
186 struct tree_entry *entry;
187 struct tree_entry *prev_entry = NULL;
188
189 if (tree->last) {
190 struct extent_state *state;
191 state = tree->last;
192 if (state->start <= offset && offset <= state->end)
193 return &tree->last->rb_node;
194 }
195 while(n) {
196 entry = rb_entry(n, struct tree_entry, rb_node);
197 prev = n;
198 prev_entry = entry;
199
200 if (offset < entry->start)
201 n = n->rb_left;
202 else if (offset > entry->end)
203 n = n->rb_right;
204 else {
205 tree->last = rb_entry(n, struct extent_state, rb_node);
206 return n;
207 }
208 }
209
210 if (prev_ret) {
211 orig_prev = prev;
212 while(prev && offset > prev_entry->end) {
213 prev = rb_next(prev);
214 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
215 }
216 *prev_ret = prev;
217 prev = orig_prev;
218 }
219
220 if (next_ret) {
221 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
222 while(prev && offset < prev_entry->start) {
223 prev = rb_prev(prev);
224 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
225 }
226 *next_ret = prev;
227 }
228 return NULL;
229 }
230
231 static inline struct rb_node *tree_search(struct extent_io_tree *tree,
232 u64 offset)
233 {
234 struct rb_node *prev = NULL;
235 struct rb_node *ret;
236
237 ret = __etree_search(tree, offset, &prev, NULL);
238 if (!ret) {
239 if (prev) {
240 tree->last = rb_entry(prev, struct extent_state,
241 rb_node);
242 }
243 return prev;
244 }
245 return ret;
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)
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 state->start = other->start;
272 other->tree = NULL;
273 if (tree->last == other)
274 tree->last = state;
275 rb_erase(&other->rb_node, &tree->state);
276 free_extent_state(other);
277 }
278 }
279 other_node = rb_next(&state->rb_node);
280 if (other_node) {
281 other = rb_entry(other_node, struct extent_state, rb_node);
282 if (other->start == state->end + 1 &&
283 other->state == state->state) {
284 other->start = state->start;
285 state->tree = NULL;
286 if (tree->last == state)
287 tree->last = other;
288 rb_erase(&state->rb_node, &tree->state);
289 free_extent_state(state);
290 }
291 }
292 return 0;
293 }
294
295 static void set_state_cb(struct extent_io_tree *tree,
296 struct extent_state *state,
297 unsigned long bits)
298 {
299 if (tree->ops && tree->ops->set_bit_hook) {
300 tree->ops->set_bit_hook(tree->mapping->host, state->start,
301 state->end, state->state, bits);
302 }
303 }
304
305 static void clear_state_cb(struct extent_io_tree *tree,
306 struct extent_state *state,
307 unsigned long bits)
308 {
309 if (tree->ops && tree->ops->set_bit_hook) {
310 tree->ops->clear_bit_hook(tree->mapping->host, state->start,
311 state->end, state->state, bits);
312 }
313 }
314
315 /*
316 * insert an extent_state struct into the tree. 'bits' are set on the
317 * struct before it is inserted.
318 *
319 * This may return -EEXIST if the extent is already there, in which case the
320 * state struct is freed.
321 *
322 * The tree lock is not taken internally. This is a utility function and
323 * probably isn't what you want to call (see set/clear_extent_bit).
324 */
325 static int insert_state(struct extent_io_tree *tree,
326 struct extent_state *state, u64 start, u64 end,
327 int bits)
328 {
329 struct rb_node *node;
330
331 if (end < start) {
332 printk("end < start %Lu %Lu\n", end, start);
333 WARN_ON(1);
334 }
335 if (bits & EXTENT_DIRTY)
336 tree->dirty_bytes += end - start + 1;
337 set_state_cb(tree, state, bits);
338 state->state |= bits;
339 state->start = start;
340 state->end = end;
341 node = tree_insert(&tree->state, end, &state->rb_node);
342 if (node) {
343 struct extent_state *found;
344 found = rb_entry(node, struct extent_state, rb_node);
345 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, start, end);
346 free_extent_state(state);
347 return -EEXIST;
348 }
349 state->tree = tree;
350 tree->last = state;
351 merge_state(tree, state);
352 return 0;
353 }
354
355 /*
356 * split a given extent state struct in two, inserting the preallocated
357 * struct 'prealloc' as the newly created second half. 'split' indicates an
358 * offset inside 'orig' where it should be split.
359 *
360 * Before calling,
361 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
362 * are two extent state structs in the tree:
363 * prealloc: [orig->start, split - 1]
364 * orig: [ split, orig->end ]
365 *
366 * The tree locks are not taken by this function. They need to be held
367 * by the caller.
368 */
369 static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
370 struct extent_state *prealloc, u64 split)
371 {
372 struct rb_node *node;
373 prealloc->start = orig->start;
374 prealloc->end = split - 1;
375 prealloc->state = orig->state;
376 orig->start = split;
377
378 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
379 if (node) {
380 struct extent_state *found;
381 found = rb_entry(node, struct extent_state, rb_node);
382 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, prealloc->start, prealloc->end);
383 free_extent_state(prealloc);
384 return -EEXIST;
385 }
386 prealloc->tree = tree;
387 return 0;
388 }
389
390 /*
391 * utility function to clear some bits in an extent state struct.
392 * it will optionally wake up any one waiting on this state (wake == 1), or
393 * forcibly remove the state from the tree (delete == 1).
394 *
395 * If no bits are set on the state struct after clearing things, the
396 * struct is freed and removed from the tree
397 */
398 static int clear_state_bit(struct extent_io_tree *tree,
399 struct extent_state *state, int bits, int wake,
400 int delete)
401 {
402 int ret = state->state & bits;
403
404 if ((bits & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
405 u64 range = state->end - state->start + 1;
406 WARN_ON(range > tree->dirty_bytes);
407 tree->dirty_bytes -= range;
408 }
409 clear_state_cb(tree, state, bits);
410 state->state &= ~bits;
411 if (wake)
412 wake_up(&state->wq);
413 if (delete || state->state == 0) {
414 if (state->tree) {
415 clear_state_cb(tree, state, state->state);
416 if (tree->last == state) {
417 tree->last = extent_state_next(state);
418 }
419 rb_erase(&state->rb_node, &tree->state);
420 state->tree = NULL;
421 free_extent_state(state);
422 } else {
423 WARN_ON(1);
424 }
425 } else {
426 merge_state(tree, state);
427 }
428 return ret;
429 }
430
431 /*
432 * clear some bits on a range in the tree. This may require splitting
433 * or inserting elements in the tree, so the gfp mask is used to
434 * indicate which allocations or sleeping are allowed.
435 *
436 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
437 * the given range from the tree regardless of state (ie for truncate).
438 *
439 * the range [start, end] is inclusive.
440 *
441 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
442 * bits were already set, or zero if none of the bits were already set.
443 */
444 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
445 int bits, int wake, int delete, gfp_t mask)
446 {
447 struct extent_state *state;
448 struct extent_state *prealloc = NULL;
449 struct rb_node *node;
450 unsigned long flags;
451 int err;
452 int set = 0;
453
454 again:
455 if (!prealloc && (mask & __GFP_WAIT)) {
456 prealloc = alloc_extent_state(mask);
457 if (!prealloc)
458 return -ENOMEM;
459 }
460
461 spin_lock_irqsave(&tree->lock, flags);
462 /*
463 * this search will find the extents that end after
464 * our range starts
465 */
466 node = tree_search(tree, start);
467 if (!node)
468 goto out;
469 state = rb_entry(node, struct extent_state, rb_node);
470 if (state->start > end)
471 goto out;
472 WARN_ON(state->end < start);
473
474 /*
475 * | ---- desired range ---- |
476 * | state | or
477 * | ------------- state -------------- |
478 *
479 * We need to split the extent we found, and may flip
480 * bits on second half.
481 *
482 * If the extent we found extends past our range, we
483 * just split and search again. It'll get split again
484 * the next time though.
485 *
486 * If the extent we found is inside our range, we clear
487 * the desired bit on it.
488 */
489
490 if (state->start < start) {
491 if (!prealloc)
492 prealloc = alloc_extent_state(GFP_ATOMIC);
493 err = split_state(tree, state, prealloc, start);
494 BUG_ON(err == -EEXIST);
495 prealloc = NULL;
496 if (err)
497 goto out;
498 if (state->end <= end) {
499 start = state->end + 1;
500 set |= clear_state_bit(tree, state, bits,
501 wake, delete);
502 } else {
503 start = state->start;
504 }
505 goto search_again;
506 }
507 /*
508 * | ---- desired range ---- |
509 * | state |
510 * We need to split the extent, and clear the bit
511 * on the first half
512 */
513 if (state->start <= end && state->end > end) {
514 if (!prealloc)
515 prealloc = alloc_extent_state(GFP_ATOMIC);
516 err = split_state(tree, state, prealloc, end + 1);
517 BUG_ON(err == -EEXIST);
518
519 if (wake)
520 wake_up(&state->wq);
521 set |= clear_state_bit(tree, prealloc, bits,
522 wake, delete);
523 prealloc = NULL;
524 goto out;
525 }
526
527 start = state->end + 1;
528 set |= clear_state_bit(tree, state, bits, wake, delete);
529 goto search_again;
530
531 out:
532 spin_unlock_irqrestore(&tree->lock, flags);
533 if (prealloc)
534 free_extent_state(prealloc);
535
536 return set;
537
538 search_again:
539 if (start > end)
540 goto out;
541 spin_unlock_irqrestore(&tree->lock, flags);
542 if (mask & __GFP_WAIT)
543 cond_resched();
544 goto again;
545 }
546 EXPORT_SYMBOL(clear_extent_bit);
547
548 static int wait_on_state(struct extent_io_tree *tree,
549 struct extent_state *state)
550 {
551 DEFINE_WAIT(wait);
552 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
553 spin_unlock_irq(&tree->lock);
554 schedule();
555 spin_lock_irq(&tree->lock);
556 finish_wait(&state->wq, &wait);
557 return 0;
558 }
559
560 /*
561 * waits for one or more bits to clear on a range in the state tree.
562 * The range [start, end] is inclusive.
563 * The tree lock is taken by this function
564 */
565 int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
566 {
567 struct extent_state *state;
568 struct rb_node *node;
569
570 spin_lock_irq(&tree->lock);
571 again:
572 while (1) {
573 /*
574 * this search will find all the extents that end after
575 * our range starts
576 */
577 node = tree_search(tree, start);
578 if (!node)
579 break;
580
581 state = rb_entry(node, struct extent_state, rb_node);
582
583 if (state->start > end)
584 goto out;
585
586 if (state->state & bits) {
587 start = state->start;
588 atomic_inc(&state->refs);
589 wait_on_state(tree, state);
590 free_extent_state(state);
591 goto again;
592 }
593 start = state->end + 1;
594
595 if (start > end)
596 break;
597
598 if (need_resched()) {
599 spin_unlock_irq(&tree->lock);
600 cond_resched();
601 spin_lock_irq(&tree->lock);
602 }
603 }
604 out:
605 spin_unlock_irq(&tree->lock);
606 return 0;
607 }
608 EXPORT_SYMBOL(wait_extent_bit);
609
610 static void set_state_bits(struct extent_io_tree *tree,
611 struct extent_state *state,
612 int bits)
613 {
614 if ((bits & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
615 u64 range = state->end - state->start + 1;
616 tree->dirty_bytes += range;
617 }
618 set_state_cb(tree, state, bits);
619 state->state |= bits;
620 }
621
622 /*
623 * set some bits on a range in the tree. This may require allocations
624 * or sleeping, so the gfp mask is used to indicate what is allowed.
625 *
626 * If 'exclusive' == 1, this will fail with -EEXIST if some part of the
627 * range already has the desired bits set. The start of the existing
628 * range is returned in failed_start in this case.
629 *
630 * [start, end] is inclusive
631 * This takes the tree lock.
632 */
633 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits,
634 int exclusive, u64 *failed_start, gfp_t mask)
635 {
636 struct extent_state *state;
637 struct extent_state *prealloc = NULL;
638 struct rb_node *node;
639 unsigned long flags;
640 int err = 0;
641 int set;
642 u64 last_start;
643 u64 last_end;
644 again:
645 if (!prealloc && (mask & __GFP_WAIT)) {
646 prealloc = alloc_extent_state(mask);
647 if (!prealloc)
648 return -ENOMEM;
649 }
650
651 spin_lock_irqsave(&tree->lock, flags);
652 /*
653 * this search will find all the extents that end after
654 * our range starts.
655 */
656 node = tree_search(tree, start);
657 if (!node) {
658 err = insert_state(tree, prealloc, start, end, bits);
659 prealloc = NULL;
660 BUG_ON(err == -EEXIST);
661 goto out;
662 }
663
664 state = rb_entry(node, struct extent_state, rb_node);
665 last_start = state->start;
666 last_end = state->end;
667
668 /*
669 * | ---- desired range ---- |
670 * | state |
671 *
672 * Just lock what we found and keep going
673 */
674 if (state->start == start && state->end <= end) {
675 set = state->state & bits;
676 if (set && exclusive) {
677 *failed_start = state->start;
678 err = -EEXIST;
679 goto out;
680 }
681 set_state_bits(tree, state, bits);
682 start = state->end + 1;
683 merge_state(tree, state);
684 goto search_again;
685 }
686
687 /*
688 * | ---- desired range ---- |
689 * | state |
690 * or
691 * | ------------- state -------------- |
692 *
693 * We need to split the extent we found, and may flip bits on
694 * second half.
695 *
696 * If the extent we found extends past our
697 * range, we just split and search again. It'll get split
698 * again the next time though.
699 *
700 * If the extent we found is inside our range, we set the
701 * desired bit on it.
702 */
703 if (state->start < start) {
704 set = state->state & bits;
705 if (exclusive && set) {
706 *failed_start = start;
707 err = -EEXIST;
708 goto out;
709 }
710 err = split_state(tree, state, prealloc, start);
711 BUG_ON(err == -EEXIST);
712 prealloc = NULL;
713 if (err)
714 goto out;
715 if (state->end <= end) {
716 set_state_bits(tree, state, bits);
717 start = state->end + 1;
718 merge_state(tree, state);
719 } else {
720 start = state->start;
721 }
722 goto search_again;
723 }
724 /*
725 * | ---- desired range ---- |
726 * | state | or | state |
727 *
728 * There's a hole, we need to insert something in it and
729 * ignore the extent we found.
730 */
731 if (state->start > start) {
732 u64 this_end;
733 if (end < last_start)
734 this_end = end;
735 else
736 this_end = last_start -1;
737 err = insert_state(tree, prealloc, start, this_end,
738 bits);
739 prealloc = NULL;
740 BUG_ON(err == -EEXIST);
741 if (err)
742 goto out;
743 start = this_end + 1;
744 goto search_again;
745 }
746 /*
747 * | ---- desired range ---- |
748 * | state |
749 * We need to split the extent, and set the bit
750 * on the first half
751 */
752 if (state->start <= end && state->end > end) {
753 set = state->state & bits;
754 if (exclusive && set) {
755 *failed_start = start;
756 err = -EEXIST;
757 goto out;
758 }
759 err = split_state(tree, state, prealloc, end + 1);
760 BUG_ON(err == -EEXIST);
761
762 set_state_bits(tree, prealloc, bits);
763 merge_state(tree, prealloc);
764 prealloc = NULL;
765 goto out;
766 }
767
768 goto search_again;
769
770 out:
771 spin_unlock_irqrestore(&tree->lock, flags);
772 if (prealloc)
773 free_extent_state(prealloc);
774
775 return err;
776
777 search_again:
778 if (start > end)
779 goto out;
780 spin_unlock_irqrestore(&tree->lock, flags);
781 if (mask & __GFP_WAIT)
782 cond_resched();
783 goto again;
784 }
785 EXPORT_SYMBOL(set_extent_bit);
786
787 /* wrappers around set/clear extent bit */
788 int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
789 gfp_t mask)
790 {
791 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
792 mask);
793 }
794 EXPORT_SYMBOL(set_extent_dirty);
795
796 int set_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
797 gfp_t mask)
798 {
799 return set_extent_bit(tree, start, end, EXTENT_ORDERED, 0, NULL, mask);
800 }
801 EXPORT_SYMBOL(set_extent_ordered);
802
803 int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
804 int bits, gfp_t mask)
805 {
806 return set_extent_bit(tree, start, end, bits, 0, NULL,
807 mask);
808 }
809 EXPORT_SYMBOL(set_extent_bits);
810
811 int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
812 int bits, gfp_t mask)
813 {
814 return clear_extent_bit(tree, start, end, bits, 0, 0, mask);
815 }
816 EXPORT_SYMBOL(clear_extent_bits);
817
818 int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
819 gfp_t mask)
820 {
821 return set_extent_bit(tree, start, end,
822 EXTENT_DELALLOC | EXTENT_DIRTY,
823 0, NULL, mask);
824 }
825 EXPORT_SYMBOL(set_extent_delalloc);
826
827 int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
828 gfp_t mask)
829 {
830 return clear_extent_bit(tree, start, end,
831 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, mask);
832 }
833 EXPORT_SYMBOL(clear_extent_dirty);
834
835 int clear_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
836 gfp_t mask)
837 {
838 return clear_extent_bit(tree, start, end, EXTENT_ORDERED, 1, 0, mask);
839 }
840 EXPORT_SYMBOL(clear_extent_ordered);
841
842 int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
843 gfp_t mask)
844 {
845 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
846 mask);
847 }
848 EXPORT_SYMBOL(set_extent_new);
849
850 int clear_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
851 gfp_t mask)
852 {
853 return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask);
854 }
855 EXPORT_SYMBOL(clear_extent_new);
856
857 int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
858 gfp_t mask)
859 {
860 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
861 mask);
862 }
863 EXPORT_SYMBOL(set_extent_uptodate);
864
865 int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
866 gfp_t mask)
867 {
868 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask);
869 }
870 EXPORT_SYMBOL(clear_extent_uptodate);
871
872 int set_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
873 gfp_t mask)
874 {
875 return set_extent_bit(tree, start, end, EXTENT_WRITEBACK,
876 0, NULL, mask);
877 }
878 EXPORT_SYMBOL(set_extent_writeback);
879
880 int clear_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
881 gfp_t mask)
882 {
883 return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask);
884 }
885 EXPORT_SYMBOL(clear_extent_writeback);
886
887 int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end)
888 {
889 return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
890 }
891 EXPORT_SYMBOL(wait_on_extent_writeback);
892
893 int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
894 {
895 int err;
896 u64 failed_start;
897 while (1) {
898 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
899 &failed_start, mask);
900 if (err == -EEXIST && (mask & __GFP_WAIT)) {
901 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
902 start = failed_start;
903 } else {
904 break;
905 }
906 WARN_ON(start > end);
907 }
908 return err;
909 }
910 EXPORT_SYMBOL(lock_extent);
911
912 int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end,
913 gfp_t mask)
914 {
915 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask);
916 }
917 EXPORT_SYMBOL(unlock_extent);
918
919 /*
920 * helper function to set pages and extents in the tree dirty
921 */
922 int set_range_dirty(struct extent_io_tree *tree, u64 start, u64 end)
923 {
924 unsigned long index = start >> PAGE_CACHE_SHIFT;
925 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
926 struct page *page;
927
928 while (index <= end_index) {
929 page = find_get_page(tree->mapping, index);
930 BUG_ON(!page);
931 __set_page_dirty_nobuffers(page);
932 page_cache_release(page);
933 index++;
934 }
935 set_extent_dirty(tree, start, end, GFP_NOFS);
936 return 0;
937 }
938 EXPORT_SYMBOL(set_range_dirty);
939
940 /*
941 * helper function to set both pages and extents in the tree writeback
942 */
943 int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
944 {
945 unsigned long index = start >> PAGE_CACHE_SHIFT;
946 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
947 struct page *page;
948
949 while (index <= end_index) {
950 page = find_get_page(tree->mapping, index);
951 BUG_ON(!page);
952 set_page_writeback(page);
953 page_cache_release(page);
954 index++;
955 }
956 set_extent_writeback(tree, start, end, GFP_NOFS);
957 return 0;
958 }
959 EXPORT_SYMBOL(set_range_writeback);
960
961 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
962 u64 *start_ret, u64 *end_ret, int bits)
963 {
964 struct rb_node *node;
965 struct extent_state *state;
966 int ret = 1;
967
968 spin_lock_irq(&tree->lock);
969 /*
970 * this search will find all the extents that end after
971 * our range starts.
972 */
973 node = tree_search(tree, start);
974 if (!node) {
975 goto out;
976 }
977
978 while(1) {
979 state = rb_entry(node, struct extent_state, rb_node);
980 if (state->end >= start && (state->state & bits)) {
981 *start_ret = state->start;
982 *end_ret = state->end;
983 ret = 0;
984 break;
985 }
986 node = rb_next(node);
987 if (!node)
988 break;
989 }
990 out:
991 spin_unlock_irq(&tree->lock);
992 return ret;
993 }
994 EXPORT_SYMBOL(find_first_extent_bit);
995
996 struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
997 u64 start, int bits)
998 {
999 struct rb_node *node;
1000 struct extent_state *state;
1001
1002 /*
1003 * this search will find all the extents that end after
1004 * our range starts.
1005 */
1006 node = tree_search(tree, start);
1007 if (!node) {
1008 goto out;
1009 }
1010
1011 while(1) {
1012 state = rb_entry(node, struct extent_state, rb_node);
1013 if (state->end >= start && (state->state & bits)) {
1014 return state;
1015 }
1016 node = rb_next(node);
1017 if (!node)
1018 break;
1019 }
1020 out:
1021 return NULL;
1022 }
1023 EXPORT_SYMBOL(find_first_extent_bit_state);
1024
1025 u64 find_lock_delalloc_range(struct extent_io_tree *tree,
1026 u64 *start, u64 *end, u64 max_bytes)
1027 {
1028 struct rb_node *node;
1029 struct extent_state *state;
1030 u64 cur_start = *start;
1031 u64 found = 0;
1032 u64 total_bytes = 0;
1033
1034 spin_lock_irq(&tree->lock);
1035 /*
1036 * this search will find all the extents that end after
1037 * our range starts.
1038 */
1039 search_again:
1040 node = tree_search(tree, cur_start);
1041 if (!node) {
1042 if (!found)
1043 *end = (u64)-1;
1044 goto out;
1045 }
1046
1047 while(1) {
1048 state = rb_entry(node, struct extent_state, rb_node);
1049 if (found && state->start != cur_start) {
1050 goto out;
1051 }
1052 if (!(state->state & EXTENT_DELALLOC)) {
1053 if (!found)
1054 *end = state->end;
1055 goto out;
1056 }
1057 if (!found) {
1058 struct extent_state *prev_state;
1059 struct rb_node *prev_node = node;
1060 while(1) {
1061 prev_node = rb_prev(prev_node);
1062 if (!prev_node)
1063 break;
1064 prev_state = rb_entry(prev_node,
1065 struct extent_state,
1066 rb_node);
1067 if (!(prev_state->state & EXTENT_DELALLOC))
1068 break;
1069 state = prev_state;
1070 node = prev_node;
1071 }
1072 }
1073 if (state->state & EXTENT_LOCKED) {
1074 DEFINE_WAIT(wait);
1075 atomic_inc(&state->refs);
1076 prepare_to_wait(&state->wq, &wait,
1077 TASK_UNINTERRUPTIBLE);
1078 spin_unlock_irq(&tree->lock);
1079 schedule();
1080 spin_lock_irq(&tree->lock);
1081 finish_wait(&state->wq, &wait);
1082 free_extent_state(state);
1083 goto search_again;
1084 }
1085 set_state_cb(tree, state, EXTENT_LOCKED);
1086 state->state |= EXTENT_LOCKED;
1087 if (!found)
1088 *start = state->start;
1089 found++;
1090 *end = state->end;
1091 cur_start = state->end + 1;
1092 node = rb_next(node);
1093 if (!node)
1094 break;
1095 total_bytes += state->end - state->start + 1;
1096 if (total_bytes >= max_bytes)
1097 break;
1098 }
1099 out:
1100 spin_unlock_irq(&tree->lock);
1101 return found;
1102 }
1103
1104 u64 count_range_bits(struct extent_io_tree *tree,
1105 u64 *start, u64 search_end, u64 max_bytes,
1106 unsigned long bits)
1107 {
1108 struct rb_node *node;
1109 struct extent_state *state;
1110 u64 cur_start = *start;
1111 u64 total_bytes = 0;
1112 int found = 0;
1113
1114 if (search_end <= cur_start) {
1115 printk("search_end %Lu start %Lu\n", search_end, cur_start);
1116 WARN_ON(1);
1117 return 0;
1118 }
1119
1120 spin_lock_irq(&tree->lock);
1121 if (cur_start == 0 && bits == EXTENT_DIRTY) {
1122 total_bytes = tree->dirty_bytes;
1123 goto out;
1124 }
1125 /*
1126 * this search will find all the extents that end after
1127 * our range starts.
1128 */
1129 node = tree_search(tree, cur_start);
1130 if (!node) {
1131 goto out;
1132 }
1133
1134 while(1) {
1135 state = rb_entry(node, struct extent_state, rb_node);
1136 if (state->start > search_end)
1137 break;
1138 if (state->end >= cur_start && (state->state & bits)) {
1139 total_bytes += min(search_end, state->end) + 1 -
1140 max(cur_start, state->start);
1141 if (total_bytes >= max_bytes)
1142 break;
1143 if (!found) {
1144 *start = state->start;
1145 found = 1;
1146 }
1147 }
1148 node = rb_next(node);
1149 if (!node)
1150 break;
1151 }
1152 out:
1153 spin_unlock_irq(&tree->lock);
1154 return total_bytes;
1155 }
1156 /*
1157 * helper function to lock both pages and extents in the tree.
1158 * pages must be locked first.
1159 */
1160 int lock_range(struct extent_io_tree *tree, u64 start, u64 end)
1161 {
1162 unsigned long index = start >> PAGE_CACHE_SHIFT;
1163 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1164 struct page *page;
1165 int err;
1166
1167 while (index <= end_index) {
1168 page = grab_cache_page(tree->mapping, index);
1169 if (!page) {
1170 err = -ENOMEM;
1171 goto failed;
1172 }
1173 if (IS_ERR(page)) {
1174 err = PTR_ERR(page);
1175 goto failed;
1176 }
1177 index++;
1178 }
1179 lock_extent(tree, start, end, GFP_NOFS);
1180 return 0;
1181
1182 failed:
1183 /*
1184 * we failed above in getting the page at 'index', so we undo here
1185 * up to but not including the page at 'index'
1186 */
1187 end_index = index;
1188 index = start >> PAGE_CACHE_SHIFT;
1189 while (index < end_index) {
1190 page = find_get_page(tree->mapping, index);
1191 unlock_page(page);
1192 page_cache_release(page);
1193 index++;
1194 }
1195 return err;
1196 }
1197 EXPORT_SYMBOL(lock_range);
1198
1199 /*
1200 * helper function to unlock both pages and extents in the tree.
1201 */
1202 int unlock_range(struct extent_io_tree *tree, u64 start, u64 end)
1203 {
1204 unsigned long index = start >> PAGE_CACHE_SHIFT;
1205 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1206 struct page *page;
1207
1208 while (index <= end_index) {
1209 page = find_get_page(tree->mapping, index);
1210 unlock_page(page);
1211 page_cache_release(page);
1212 index++;
1213 }
1214 unlock_extent(tree, start, end, GFP_NOFS);
1215 return 0;
1216 }
1217 EXPORT_SYMBOL(unlock_range);
1218
1219 int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1220 {
1221 struct rb_node *node;
1222 struct extent_state *state;
1223 int ret = 0;
1224
1225 spin_lock_irq(&tree->lock);
1226 /*
1227 * this search will find all the extents that end after
1228 * our range starts.
1229 */
1230 node = tree_search(tree, start);
1231 if (!node) {
1232 ret = -ENOENT;
1233 goto out;
1234 }
1235 state = rb_entry(node, struct extent_state, rb_node);
1236 if (state->start != start) {
1237 ret = -ENOENT;
1238 goto out;
1239 }
1240 state->private = private;
1241 out:
1242 spin_unlock_irq(&tree->lock);
1243 return ret;
1244 }
1245
1246 int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
1247 {
1248 struct rb_node *node;
1249 struct extent_state *state;
1250 int ret = 0;
1251
1252 spin_lock_irq(&tree->lock);
1253 /*
1254 * this search will find all the extents that end after
1255 * our range starts.
1256 */
1257 node = tree_search(tree, start);
1258 if (!node) {
1259 ret = -ENOENT;
1260 goto out;
1261 }
1262 state = rb_entry(node, struct extent_state, rb_node);
1263 if (state->start != start) {
1264 ret = -ENOENT;
1265 goto out;
1266 }
1267 *private = state->private;
1268 out:
1269 spin_unlock_irq(&tree->lock);
1270 return ret;
1271 }
1272
1273 /*
1274 * searches a range in the state tree for a given mask.
1275 * If 'filled' == 1, this returns 1 only if every extent in the tree
1276 * has the bits set. Otherwise, 1 is returned if any bit in the
1277 * range is found set.
1278 */
1279 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1280 int bits, int filled)
1281 {
1282 struct extent_state *state = NULL;
1283 struct rb_node *node;
1284 int bitset = 0;
1285 unsigned long flags;
1286
1287 spin_lock_irqsave(&tree->lock, flags);
1288 node = tree_search(tree, start);
1289 while (node && start <= end) {
1290 state = rb_entry(node, struct extent_state, rb_node);
1291
1292 if (filled && state->start > start) {
1293 bitset = 0;
1294 break;
1295 }
1296
1297 if (state->start > end)
1298 break;
1299
1300 if (state->state & bits) {
1301 bitset = 1;
1302 if (!filled)
1303 break;
1304 } else if (filled) {
1305 bitset = 0;
1306 break;
1307 }
1308 start = state->end + 1;
1309 if (start > end)
1310 break;
1311 node = rb_next(node);
1312 if (!node) {
1313 if (filled)
1314 bitset = 0;
1315 break;
1316 }
1317 }
1318 spin_unlock_irqrestore(&tree->lock, flags);
1319 return bitset;
1320 }
1321 EXPORT_SYMBOL(test_range_bit);
1322
1323 /*
1324 * helper function to set a given page up to date if all the
1325 * extents in the tree for that page are up to date
1326 */
1327 static int check_page_uptodate(struct extent_io_tree *tree,
1328 struct page *page)
1329 {
1330 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1331 u64 end = start + PAGE_CACHE_SIZE - 1;
1332 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1))
1333 SetPageUptodate(page);
1334 return 0;
1335 }
1336
1337 /*
1338 * helper function to unlock a page if all the extents in the tree
1339 * for that page are unlocked
1340 */
1341 static int check_page_locked(struct extent_io_tree *tree,
1342 struct page *page)
1343 {
1344 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1345 u64 end = start + PAGE_CACHE_SIZE - 1;
1346 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0))
1347 unlock_page(page);
1348 return 0;
1349 }
1350
1351 /*
1352 * helper function to end page writeback if all the extents
1353 * in the tree for that page are done with writeback
1354 */
1355 static int check_page_writeback(struct extent_io_tree *tree,
1356 struct page *page)
1357 {
1358 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1359 u64 end = start + PAGE_CACHE_SIZE - 1;
1360 if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0))
1361 end_page_writeback(page);
1362 return 0;
1363 }
1364
1365 /* lots and lots of room for performance fixes in the end_bio funcs */
1366
1367 /*
1368 * after a writepage IO is done, we need to:
1369 * clear the uptodate bits on error
1370 * clear the writeback bits in the extent tree for this IO
1371 * end_page_writeback if the page has no more pending IO
1372 *
1373 * Scheduling is not allowed, so the extent state tree is expected
1374 * to have one and only one object corresponding to this IO.
1375 */
1376 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1377 static void end_bio_extent_writepage(struct bio *bio, int err)
1378 #else
1379 static int end_bio_extent_writepage(struct bio *bio,
1380 unsigned int bytes_done, int err)
1381 #endif
1382 {
1383 int uptodate = err == 0;
1384 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1385 struct extent_state *state = bio->bi_private;
1386 struct extent_io_tree *tree = state->tree;
1387 struct rb_node *node;
1388 u64 start;
1389 u64 end;
1390 u64 cur;
1391 int whole_page;
1392 int ret;
1393 unsigned long flags;
1394
1395 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1396 if (bio->bi_size)
1397 return 1;
1398 #endif
1399 do {
1400 struct page *page = bvec->bv_page;
1401 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1402 bvec->bv_offset;
1403 end = start + bvec->bv_len - 1;
1404
1405 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1406 whole_page = 1;
1407 else
1408 whole_page = 0;
1409
1410 if (--bvec >= bio->bi_io_vec)
1411 prefetchw(&bvec->bv_page->flags);
1412 if (tree->ops && tree->ops->writepage_end_io_hook) {
1413 ret = tree->ops->writepage_end_io_hook(page, start,
1414 end, state, uptodate);
1415 if (ret)
1416 uptodate = 0;
1417 }
1418
1419 if (!uptodate && tree->ops &&
1420 tree->ops->writepage_io_failed_hook) {
1421 ret = tree->ops->writepage_io_failed_hook(bio, page,
1422 start, end, state);
1423 if (ret == 0) {
1424 state = NULL;
1425 uptodate = (err == 0);
1426 continue;
1427 }
1428 }
1429
1430 if (!uptodate) {
1431 clear_extent_uptodate(tree, start, end, GFP_ATOMIC);
1432 ClearPageUptodate(page);
1433 SetPageError(page);
1434 }
1435
1436 /*
1437 * bios can get merged in funny ways, and so we need to
1438 * be careful with the state variable. We know the
1439 * state won't be merged with others because it has
1440 * WRITEBACK set, but we can't be sure each biovec is
1441 * sequential in the file. So, if our cached state
1442 * doesn't match the expected end, search the tree
1443 * for the correct one.
1444 */
1445
1446 spin_lock_irqsave(&tree->lock, flags);
1447 if (!state || state->end != end) {
1448 state = NULL;
1449 node = __etree_search(tree, start, NULL, NULL);
1450 if (node) {
1451 state = rb_entry(node, struct extent_state,
1452 rb_node);
1453 if (state->end != end ||
1454 !(state->state & EXTENT_WRITEBACK))
1455 state = NULL;
1456 }
1457 if (!state) {
1458 spin_unlock_irqrestore(&tree->lock, flags);
1459 clear_extent_writeback(tree, start,
1460 end, GFP_ATOMIC);
1461 goto next_io;
1462 }
1463 }
1464 cur = end;
1465 while(1) {
1466 struct extent_state *clear = state;
1467 cur = state->start;
1468 node = rb_prev(&state->rb_node);
1469 if (node) {
1470 state = rb_entry(node,
1471 struct extent_state,
1472 rb_node);
1473 } else {
1474 state = NULL;
1475 }
1476
1477 clear_state_bit(tree, clear, EXTENT_WRITEBACK,
1478 1, 0);
1479 if (cur == start)
1480 break;
1481 if (cur < start) {
1482 WARN_ON(1);
1483 break;
1484 }
1485 if (!node)
1486 break;
1487 }
1488 /* before releasing the lock, make sure the next state
1489 * variable has the expected bits set and corresponds
1490 * to the correct offsets in the file
1491 */
1492 if (state && (state->end + 1 != start ||
1493 !(state->state & EXTENT_WRITEBACK))) {
1494 state = NULL;
1495 }
1496 spin_unlock_irqrestore(&tree->lock, flags);
1497 next_io:
1498
1499 if (whole_page)
1500 end_page_writeback(page);
1501 else
1502 check_page_writeback(tree, page);
1503 } while (bvec >= bio->bi_io_vec);
1504 bio_put(bio);
1505 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1506 return 0;
1507 #endif
1508 }
1509
1510 /*
1511 * after a readpage IO is done, we need to:
1512 * clear the uptodate bits on error
1513 * set the uptodate bits if things worked
1514 * set the page up to date if all extents in the tree are uptodate
1515 * clear the lock bit in the extent tree
1516 * unlock the page if there are no other extents locked for it
1517 *
1518 * Scheduling is not allowed, so the extent state tree is expected
1519 * to have one and only one object corresponding to this IO.
1520 */
1521 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1522 static void end_bio_extent_readpage(struct bio *bio, int err)
1523 #else
1524 static int end_bio_extent_readpage(struct bio *bio,
1525 unsigned int bytes_done, int err)
1526 #endif
1527 {
1528 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1529 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1530 struct extent_state *state = bio->bi_private;
1531 struct extent_io_tree *tree = state->tree;
1532 struct rb_node *node;
1533 u64 start;
1534 u64 end;
1535 u64 cur;
1536 unsigned long flags;
1537 int whole_page;
1538 int ret;
1539
1540 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1541 if (bio->bi_size)
1542 return 1;
1543 #endif
1544
1545 do {
1546 struct page *page = bvec->bv_page;
1547 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1548 bvec->bv_offset;
1549 end = start + bvec->bv_len - 1;
1550
1551 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1552 whole_page = 1;
1553 else
1554 whole_page = 0;
1555
1556 if (--bvec >= bio->bi_io_vec)
1557 prefetchw(&bvec->bv_page->flags);
1558
1559 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1560 ret = tree->ops->readpage_end_io_hook(page, start, end,
1561 state);
1562 if (ret)
1563 uptodate = 0;
1564 }
1565 if (!uptodate && tree->ops &&
1566 tree->ops->readpage_io_failed_hook) {
1567 ret = tree->ops->readpage_io_failed_hook(bio, page,
1568 start, end, state);
1569 if (ret == 0) {
1570 state = NULL;
1571 uptodate =
1572 test_bit(BIO_UPTODATE, &bio->bi_flags);
1573 continue;
1574 }
1575 }
1576
1577 spin_lock_irqsave(&tree->lock, flags);
1578 if (!state || state->end != end) {
1579 state = NULL;
1580 node = __etree_search(tree, start, NULL, NULL);
1581 if (node) {
1582 state = rb_entry(node, struct extent_state,
1583 rb_node);
1584 if (state->end != end ||
1585 !(state->state & EXTENT_LOCKED))
1586 state = NULL;
1587 }
1588 if (!state) {
1589 spin_unlock_irqrestore(&tree->lock, flags);
1590 if (uptodate)
1591 set_extent_uptodate(tree, start, end,
1592 GFP_ATOMIC);
1593 unlock_extent(tree, start, end, GFP_ATOMIC);
1594 goto next_io;
1595 }
1596 }
1597
1598 cur = end;
1599 while(1) {
1600 struct extent_state *clear = state;
1601 cur = state->start;
1602 node = rb_prev(&state->rb_node);
1603 if (node) {
1604 state = rb_entry(node,
1605 struct extent_state,
1606 rb_node);
1607 } else {
1608 state = NULL;
1609 }
1610 if (uptodate) {
1611 set_state_cb(tree, clear, EXTENT_UPTODATE);
1612 clear->state |= EXTENT_UPTODATE;
1613 }
1614 clear_state_bit(tree, clear, EXTENT_LOCKED,
1615 1, 0);
1616 if (cur == start)
1617 break;
1618 if (cur < start) {
1619 WARN_ON(1);
1620 break;
1621 }
1622 if (!node)
1623 break;
1624 }
1625 /* before releasing the lock, make sure the next state
1626 * variable has the expected bits set and corresponds
1627 * to the correct offsets in the file
1628 */
1629 if (state && (state->end + 1 != start ||
1630 !(state->state & EXTENT_LOCKED))) {
1631 state = NULL;
1632 }
1633 spin_unlock_irqrestore(&tree->lock, flags);
1634 next_io:
1635 if (whole_page) {
1636 if (uptodate) {
1637 SetPageUptodate(page);
1638 } else {
1639 ClearPageUptodate(page);
1640 SetPageError(page);
1641 }
1642 unlock_page(page);
1643 } else {
1644 if (uptodate) {
1645 check_page_uptodate(tree, page);
1646 } else {
1647 ClearPageUptodate(page);
1648 SetPageError(page);
1649 }
1650 check_page_locked(tree, page);
1651 }
1652 } while (bvec >= bio->bi_io_vec);
1653
1654 bio_put(bio);
1655 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1656 return 0;
1657 #endif
1658 }
1659
1660 /*
1661 * IO done from prepare_write is pretty simple, we just unlock
1662 * the structs in the extent tree when done, and set the uptodate bits
1663 * as appropriate.
1664 */
1665 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1666 static void end_bio_extent_preparewrite(struct bio *bio, int err)
1667 #else
1668 static int end_bio_extent_preparewrite(struct bio *bio,
1669 unsigned int bytes_done, int err)
1670 #endif
1671 {
1672 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1673 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1674 struct extent_state *state = bio->bi_private;
1675 struct extent_io_tree *tree = state->tree;
1676 u64 start;
1677 u64 end;
1678
1679 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1680 if (bio->bi_size)
1681 return 1;
1682 #endif
1683
1684 do {
1685 struct page *page = bvec->bv_page;
1686 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
1687 bvec->bv_offset;
1688 end = start + bvec->bv_len - 1;
1689
1690 if (--bvec >= bio->bi_io_vec)
1691 prefetchw(&bvec->bv_page->flags);
1692
1693 if (uptodate) {
1694 set_extent_uptodate(tree, start, end, GFP_ATOMIC);
1695 } else {
1696 ClearPageUptodate(page);
1697 SetPageError(page);
1698 }
1699
1700 unlock_extent(tree, start, end, GFP_ATOMIC);
1701
1702 } while (bvec >= bio->bi_io_vec);
1703
1704 bio_put(bio);
1705 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1706 return 0;
1707 #endif
1708 }
1709
1710 static struct bio *
1711 extent_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
1712 gfp_t gfp_flags)
1713 {
1714 struct bio *bio;
1715
1716 bio = bio_alloc(gfp_flags, nr_vecs);
1717
1718 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
1719 while (!bio && (nr_vecs /= 2))
1720 bio = bio_alloc(gfp_flags, nr_vecs);
1721 }
1722
1723 if (bio) {
1724 bio->bi_size = 0;
1725 bio->bi_bdev = bdev;
1726 bio->bi_sector = first_sector;
1727 }
1728 return bio;
1729 }
1730
1731 static int submit_one_bio(int rw, struct bio *bio, int mirror_num)
1732 {
1733 int ret = 0;
1734 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1735 struct page *page = bvec->bv_page;
1736 struct extent_io_tree *tree = bio->bi_private;
1737 struct rb_node *node;
1738 struct extent_state *state;
1739 u64 start;
1740 u64 end;
1741
1742 start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1743 end = start + bvec->bv_len - 1;
1744
1745 spin_lock_irq(&tree->lock);
1746 node = __etree_search(tree, start, NULL, NULL);
1747 BUG_ON(!node);
1748 state = rb_entry(node, struct extent_state, rb_node);
1749 while(state->end < end) {
1750 node = rb_next(node);
1751 state = rb_entry(node, struct extent_state, rb_node);
1752 }
1753 BUG_ON(state->end != end);
1754 spin_unlock_irq(&tree->lock);
1755
1756 bio->bi_private = state;
1757
1758 bio_get(bio);
1759
1760 if (tree->ops && tree->ops->submit_bio_hook)
1761 tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1762 mirror_num);
1763 else
1764 submit_bio(rw, bio);
1765 if (bio_flagged(bio, BIO_EOPNOTSUPP))
1766 ret = -EOPNOTSUPP;
1767 bio_put(bio);
1768 return ret;
1769 }
1770
1771 static int submit_extent_page(int rw, struct extent_io_tree *tree,
1772 struct page *page, sector_t sector,
1773 size_t size, unsigned long offset,
1774 struct block_device *bdev,
1775 struct bio **bio_ret,
1776 unsigned long max_pages,
1777 bio_end_io_t end_io_func,
1778 int mirror_num)
1779 {
1780 int ret = 0;
1781 struct bio *bio;
1782 int nr;
1783
1784 if (bio_ret && *bio_ret) {
1785 bio = *bio_ret;
1786 if (bio->bi_sector + (bio->bi_size >> 9) != sector ||
1787 (tree->ops && tree->ops->merge_bio_hook &&
1788 tree->ops->merge_bio_hook(page, offset, size, bio)) ||
1789 bio_add_page(bio, page, size, offset) < size) {
1790 ret = submit_one_bio(rw, bio, mirror_num);
1791 bio = NULL;
1792 } else {
1793 return 0;
1794 }
1795 }
1796 nr = bio_get_nr_vecs(bdev);
1797 bio = extent_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1798 if (!bio) {
1799 printk("failed to allocate bio nr %d\n", nr);
1800 }
1801
1802
1803 bio_add_page(bio, page, size, offset);
1804 bio->bi_end_io = end_io_func;
1805 bio->bi_private = tree;
1806
1807 if (bio_ret) {
1808 *bio_ret = bio;
1809 } else {
1810 ret = submit_one_bio(rw, bio, mirror_num);
1811 }
1812
1813 return ret;
1814 }
1815
1816 void set_page_extent_mapped(struct page *page)
1817 {
1818 if (!PagePrivate(page)) {
1819 SetPagePrivate(page);
1820 WARN_ON(!page->mapping->a_ops->invalidatepage);
1821 set_page_private(page, EXTENT_PAGE_PRIVATE);
1822 page_cache_get(page);
1823 }
1824 }
1825
1826 void set_page_extent_head(struct page *page, unsigned long len)
1827 {
1828 set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
1829 }
1830
1831 /*
1832 * basic readpage implementation. Locked extent state structs are inserted
1833 * into the tree that are removed when the IO is done (by the end_io
1834 * handlers)
1835 */
1836 static int __extent_read_full_page(struct extent_io_tree *tree,
1837 struct page *page,
1838 get_extent_t *get_extent,
1839 struct bio **bio, int mirror_num)
1840 {
1841 struct inode *inode = page->mapping->host;
1842 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1843 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1844 u64 end;
1845 u64 cur = start;
1846 u64 extent_offset;
1847 u64 last_byte = i_size_read(inode);
1848 u64 block_start;
1849 u64 cur_end;
1850 sector_t sector;
1851 struct extent_map *em;
1852 struct block_device *bdev;
1853 int ret;
1854 int nr = 0;
1855 size_t page_offset = 0;
1856 size_t iosize;
1857 size_t blocksize = inode->i_sb->s_blocksize;
1858
1859 set_page_extent_mapped(page);
1860
1861 end = page_end;
1862 lock_extent(tree, start, end, GFP_NOFS);
1863
1864 while (cur <= end) {
1865 if (cur >= last_byte) {
1866 char *userpage;
1867 iosize = PAGE_CACHE_SIZE - page_offset;
1868 userpage = kmap_atomic(page, KM_USER0);
1869 memset(userpage + page_offset, 0, iosize);
1870 flush_dcache_page(page);
1871 kunmap_atomic(userpage, KM_USER0);
1872 set_extent_uptodate(tree, cur, cur + iosize - 1,
1873 GFP_NOFS);
1874 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1875 break;
1876 }
1877 em = get_extent(inode, page, page_offset, cur,
1878 end - cur + 1, 0);
1879 if (IS_ERR(em) || !em) {
1880 SetPageError(page);
1881 unlock_extent(tree, cur, end, GFP_NOFS);
1882 break;
1883 }
1884 extent_offset = cur - em->start;
1885 if (extent_map_end(em) <= cur) {
1886 printk("bad mapping em [%Lu %Lu] cur %Lu\n", em->start, extent_map_end(em), cur);
1887 }
1888 BUG_ON(extent_map_end(em) <= cur);
1889 if (end < cur) {
1890 printk("2bad mapping end %Lu cur %Lu\n", end, cur);
1891 }
1892 BUG_ON(end < cur);
1893
1894 iosize = min(extent_map_end(em) - cur, end - cur + 1);
1895 cur_end = min(extent_map_end(em) - 1, end);
1896 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
1897 sector = (em->block_start + extent_offset) >> 9;
1898 bdev = em->bdev;
1899 block_start = em->block_start;
1900 free_extent_map(em);
1901 em = NULL;
1902
1903 /* we've found a hole, just zero and go on */
1904 if (block_start == EXTENT_MAP_HOLE) {
1905 char *userpage;
1906 userpage = kmap_atomic(page, KM_USER0);
1907 memset(userpage + page_offset, 0, iosize);
1908 flush_dcache_page(page);
1909 kunmap_atomic(userpage, KM_USER0);
1910
1911 set_extent_uptodate(tree, cur, cur + iosize - 1,
1912 GFP_NOFS);
1913 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1914 cur = cur + iosize;
1915 page_offset += iosize;
1916 continue;
1917 }
1918 /* the get_extent function already copied into the page */
1919 if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) {
1920 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1921 cur = cur + iosize;
1922 page_offset += iosize;
1923 continue;
1924 }
1925 /* we have an inline extent but it didn't get marked up
1926 * to date. Error out
1927 */
1928 if (block_start == EXTENT_MAP_INLINE) {
1929 SetPageError(page);
1930 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1931 cur = cur + iosize;
1932 page_offset += iosize;
1933 continue;
1934 }
1935
1936 ret = 0;
1937 if (tree->ops && tree->ops->readpage_io_hook) {
1938 ret = tree->ops->readpage_io_hook(page, cur,
1939 cur + iosize - 1);
1940 }
1941 if (!ret) {
1942 unsigned long nr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
1943 nr -= page->index;
1944 ret = submit_extent_page(READ, tree, page,
1945 sector, iosize, page_offset,
1946 bdev, bio, nr,
1947 end_bio_extent_readpage, mirror_num);
1948 }
1949 if (ret)
1950 SetPageError(page);
1951 cur = cur + iosize;
1952 page_offset += iosize;
1953 nr++;
1954 }
1955 if (!nr) {
1956 if (!PageError(page))
1957 SetPageUptodate(page);
1958 unlock_page(page);
1959 }
1960 return 0;
1961 }
1962
1963 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
1964 get_extent_t *get_extent)
1965 {
1966 struct bio *bio = NULL;
1967 int ret;
1968
1969 ret = __extent_read_full_page(tree, page, get_extent, &bio, 0);
1970 if (bio)
1971 submit_one_bio(READ, bio, 0);
1972 return ret;
1973 }
1974 EXPORT_SYMBOL(extent_read_full_page);
1975
1976 /*
1977 * the writepage semantics are similar to regular writepage. extent
1978 * records are inserted to lock ranges in the tree, and as dirty areas
1979 * are found, they are marked writeback. Then the lock bits are removed
1980 * and the end_io handler clears the writeback ranges
1981 */
1982 static int __extent_writepage(struct page *page, struct writeback_control *wbc,
1983 void *data)
1984 {
1985 struct inode *inode = page->mapping->host;
1986 struct extent_page_data *epd = data;
1987 struct extent_io_tree *tree = epd->tree;
1988 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
1989 u64 delalloc_start;
1990 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1991 u64 end;
1992 u64 cur = start;
1993 u64 extent_offset;
1994 u64 last_byte = i_size_read(inode);
1995 u64 block_start;
1996 u64 iosize;
1997 u64 unlock_start;
1998 sector_t sector;
1999 struct extent_map *em;
2000 struct block_device *bdev;
2001 int ret;
2002 int nr = 0;
2003 size_t page_offset = 0;
2004 size_t blocksize;
2005 loff_t i_size = i_size_read(inode);
2006 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
2007 u64 nr_delalloc;
2008 u64 delalloc_end;
2009
2010 WARN_ON(!PageLocked(page));
2011 page_offset = i_size & (PAGE_CACHE_SIZE - 1);
2012 if (page->index > end_index ||
2013 (page->index == end_index && !page_offset)) {
2014 page->mapping->a_ops->invalidatepage(page, 0);
2015 unlock_page(page);
2016 return 0;
2017 }
2018
2019 if (page->index == end_index) {
2020 char *userpage;
2021
2022 userpage = kmap_atomic(page, KM_USER0);
2023 memset(userpage + page_offset, 0,
2024 PAGE_CACHE_SIZE - page_offset);
2025 kunmap_atomic(userpage, KM_USER0);
2026 flush_dcache_page(page);
2027 }
2028 page_offset = 0;
2029
2030 set_page_extent_mapped(page);
2031
2032 delalloc_start = start;
2033 delalloc_end = 0;
2034 while(delalloc_end < page_end) {
2035 nr_delalloc = find_lock_delalloc_range(tree, &delalloc_start,
2036 &delalloc_end,
2037 128 * 1024 * 1024);
2038 if (nr_delalloc == 0) {
2039 delalloc_start = delalloc_end + 1;
2040 continue;
2041 }
2042 tree->ops->fill_delalloc(inode, delalloc_start,
2043 delalloc_end);
2044 clear_extent_bit(tree, delalloc_start,
2045 delalloc_end,
2046 EXTENT_LOCKED | EXTENT_DELALLOC,
2047 1, 0, GFP_NOFS);
2048 delalloc_start = delalloc_end + 1;
2049 }
2050 lock_extent(tree, start, page_end, GFP_NOFS);
2051 unlock_start = start;
2052
2053 if (tree->ops && tree->ops->writepage_start_hook) {
2054 ret = tree->ops->writepage_start_hook(page, start, page_end);
2055 if (ret == -EAGAIN) {
2056 unlock_extent(tree, start, page_end, GFP_NOFS);
2057 redirty_page_for_writepage(wbc, page);
2058 unlock_page(page);
2059 return 0;
2060 }
2061 }
2062
2063 end = page_end;
2064 if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {
2065 printk("found delalloc bits after lock_extent\n");
2066 }
2067
2068 if (last_byte <= start) {
2069 clear_extent_dirty(tree, start, page_end, GFP_NOFS);
2070 unlock_extent(tree, start, page_end, GFP_NOFS);
2071 if (tree->ops && tree->ops->writepage_end_io_hook)
2072 tree->ops->writepage_end_io_hook(page, start,
2073 page_end, NULL, 1);
2074 unlock_start = page_end + 1;
2075 goto done;
2076 }
2077
2078 set_extent_uptodate(tree, start, page_end, GFP_NOFS);
2079 blocksize = inode->i_sb->s_blocksize;
2080
2081 while (cur <= end) {
2082 if (cur >= last_byte) {
2083 clear_extent_dirty(tree, cur, page_end, GFP_NOFS);
2084 unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
2085 if (tree->ops && tree->ops->writepage_end_io_hook)
2086 tree->ops->writepage_end_io_hook(page, cur,
2087 page_end, NULL, 1);
2088 unlock_start = page_end + 1;
2089 break;
2090 }
2091 em = epd->get_extent(inode, page, page_offset, cur,
2092 end - cur + 1, 1);
2093 if (IS_ERR(em) || !em) {
2094 SetPageError(page);
2095 break;
2096 }
2097
2098 extent_offset = cur - em->start;
2099 BUG_ON(extent_map_end(em) <= cur);
2100 BUG_ON(end < cur);
2101 iosize = min(extent_map_end(em) - cur, end - cur + 1);
2102 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
2103 sector = (em->block_start + extent_offset) >> 9;
2104 bdev = em->bdev;
2105 block_start = em->block_start;
2106 free_extent_map(em);
2107 em = NULL;
2108
2109 if (block_start == EXTENT_MAP_HOLE ||
2110 block_start == EXTENT_MAP_INLINE) {
2111 clear_extent_dirty(tree, cur,
2112 cur + iosize - 1, GFP_NOFS);
2113
2114 unlock_extent(tree, unlock_start, cur + iosize -1,
2115 GFP_NOFS);
2116 if (tree->ops && tree->ops->writepage_end_io_hook)
2117 tree->ops->writepage_end_io_hook(page, cur,
2118 cur + iosize - 1,
2119 NULL, 1);
2120 cur = cur + iosize;
2121 page_offset += iosize;
2122 unlock_start = cur;
2123 continue;
2124 }
2125
2126 /* leave this out until we have a page_mkwrite call */
2127 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2128 EXTENT_DIRTY, 0)) {
2129 cur = cur + iosize;
2130 page_offset += iosize;
2131 continue;
2132 }
2133 clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS);
2134 if (tree->ops && tree->ops->writepage_io_hook) {
2135 ret = tree->ops->writepage_io_hook(page, cur,
2136 cur + iosize - 1);
2137 } else {
2138 ret = 0;
2139 }
2140 if (ret) {
2141 SetPageError(page);
2142 } else {
2143 unsigned long max_nr = end_index + 1;
2144 set_range_writeback(tree, cur, cur + iosize - 1);
2145 if (!PageWriteback(page)) {
2146 printk("warning page %lu not writeback, "
2147 "cur %llu end %llu\n", page->index,
2148 (unsigned long long)cur,
2149 (unsigned long long)end);
2150 }
2151
2152 ret = submit_extent_page(WRITE, tree, page, sector,
2153 iosize, page_offset, bdev,
2154 &epd->bio, max_nr,
2155 end_bio_extent_writepage, 0);
2156 if (ret)
2157 SetPageError(page);
2158 }
2159 cur = cur + iosize;
2160 page_offset += iosize;
2161 nr++;
2162 }
2163 done:
2164 if (nr == 0) {
2165 /* make sure the mapping tag for page dirty gets cleared */
2166 set_page_writeback(page);
2167 end_page_writeback(page);
2168 }
2169 if (unlock_start <= page_end)
2170 unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
2171 unlock_page(page);
2172 return 0;
2173 }
2174
2175 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
2176 /* Taken directly from 2.6.23 for 2.6.18 back port */
2177 typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
2178 void *data);
2179
2180 /**
2181 * write_cache_pages - walk the list of dirty pages of the given address space
2182 * and write all of them.
2183 * @mapping: address space structure to write
2184 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
2185 * @writepage: function called for each page
2186 * @data: data passed to writepage function
2187 *
2188 * If a page is already under I/O, write_cache_pages() skips it, even
2189 * if it's dirty. This is desirable behaviour for memory-cleaning writeback,
2190 * but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
2191 * and msync() need to guarantee that all the data which was dirty at the time
2192 * the call was made get new I/O started against them. If wbc->sync_mode is
2193 * WB_SYNC_ALL then we were called for data integrity and we must wait for
2194 * existing IO to complete.
2195 */
2196 static int write_cache_pages(struct address_space *mapping,
2197 struct writeback_control *wbc, writepage_t writepage,
2198 void *data)
2199 {
2200 struct backing_dev_info *bdi = mapping->backing_dev_info;
2201 int ret = 0;
2202 int done = 0;
2203 struct pagevec pvec;
2204 int nr_pages;
2205 pgoff_t index;
2206 pgoff_t end; /* Inclusive */
2207 int scanned = 0;
2208 int range_whole = 0;
2209
2210 if (wbc->nonblocking && bdi_write_congested(bdi)) {
2211 wbc->encountered_congestion = 1;
2212 return 0;
2213 }
2214
2215 pagevec_init(&pvec, 0);
2216 if (wbc->range_cyclic) {
2217 index = mapping->writeback_index; /* Start from prev offset */
2218 end = -1;
2219 } else {
2220 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2221 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2222 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2223 range_whole = 1;
2224 scanned = 1;
2225 }
2226 retry:
2227 while (!done && (index <= end) &&
2228 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
2229 PAGECACHE_TAG_DIRTY,
2230 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2231 unsigned i;
2232
2233 scanned = 1;
2234 for (i = 0; i < nr_pages; i++) {
2235 struct page *page = pvec.pages[i];
2236
2237 /*
2238 * At this point we hold neither mapping->tree_lock nor
2239 * lock on the page itself: the page may be truncated or
2240 * invalidated (changing page->mapping to NULL), or even
2241 * swizzled back from swapper_space to tmpfs file
2242 * mapping
2243 */
2244 lock_page(page);
2245
2246 if (unlikely(page->mapping != mapping)) {
2247 unlock_page(page);
2248 continue;
2249 }
2250
2251 if (!wbc->range_cyclic && page->index > end) {
2252 done = 1;
2253 unlock_page(page);
2254 continue;
2255 }
2256
2257 if (wbc->sync_mode != WB_SYNC_NONE)
2258 wait_on_page_writeback(page);
2259
2260 if (PageWriteback(page) ||
2261 !clear_page_dirty_for_io(page)) {
2262 unlock_page(page);
2263 continue;
2264 }
2265
2266 ret = (*writepage)(page, wbc, data);
2267
2268 if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
2269 unlock_page(page);
2270 ret = 0;
2271 }
2272 if (ret || (--(wbc->nr_to_write) <= 0))
2273 done = 1;
2274 if (wbc->nonblocking && bdi_write_congested(bdi)) {
2275 wbc->encountered_congestion = 1;
2276 done = 1;
2277 }
2278 }
2279 pagevec_release(&pvec);
2280 cond_resched();
2281 }
2282 if (!scanned && !done) {
2283 /*
2284 * We hit the last page and there is more work to be done: wrap
2285 * back to the start of the file
2286 */
2287 scanned = 1;
2288 index = 0;
2289 goto retry;
2290 }
2291 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2292 mapping->writeback_index = index;
2293 return ret;
2294 }
2295 #endif
2296
2297 int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
2298 get_extent_t *get_extent,
2299 struct writeback_control *wbc)
2300 {
2301 int ret;
2302 struct address_space *mapping = page->mapping;
2303 struct extent_page_data epd = {
2304 .bio = NULL,
2305 .tree = tree,
2306 .get_extent = get_extent,
2307 };
2308 struct writeback_control wbc_writepages = {
2309 .bdi = wbc->bdi,
2310 .sync_mode = WB_SYNC_NONE,
2311 .older_than_this = NULL,
2312 .nr_to_write = 64,
2313 .range_start = page_offset(page) + PAGE_CACHE_SIZE,
2314 .range_end = (loff_t)-1,
2315 };
2316
2317
2318 ret = __extent_writepage(page, wbc, &epd);
2319
2320 write_cache_pages(mapping, &wbc_writepages, __extent_writepage, &epd);
2321 if (epd.bio) {
2322 submit_one_bio(WRITE, epd.bio, 0);
2323 }
2324 return ret;
2325 }
2326 EXPORT_SYMBOL(extent_write_full_page);
2327
2328
2329 int extent_writepages(struct extent_io_tree *tree,
2330 struct address_space *mapping,
2331 get_extent_t *get_extent,
2332 struct writeback_control *wbc)
2333 {
2334 int ret = 0;
2335 struct extent_page_data epd = {
2336 .bio = NULL,
2337 .tree = tree,
2338 .get_extent = get_extent,
2339 };
2340
2341 ret = write_cache_pages(mapping, wbc, __extent_writepage, &epd);
2342 if (epd.bio) {
2343 submit_one_bio(WRITE, epd.bio, 0);
2344 }
2345 return ret;
2346 }
2347 EXPORT_SYMBOL(extent_writepages);
2348
2349 int extent_readpages(struct extent_io_tree *tree,
2350 struct address_space *mapping,
2351 struct list_head *pages, unsigned nr_pages,
2352 get_extent_t get_extent)
2353 {
2354 struct bio *bio = NULL;
2355 unsigned page_idx;
2356 struct pagevec pvec;
2357
2358 pagevec_init(&pvec, 0);
2359 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
2360 struct page *page = list_entry(pages->prev, struct page, lru);
2361
2362 prefetchw(&page->flags);
2363 list_del(&page->lru);
2364 /*
2365 * what we want to do here is call add_to_page_cache_lru,
2366 * but that isn't exported, so we reproduce it here
2367 */
2368 if (!add_to_page_cache(page, mapping,
2369 page->index, GFP_KERNEL)) {
2370
2371 /* open coding of lru_cache_add, also not exported */
2372 page_cache_get(page);
2373 if (!pagevec_add(&pvec, page))
2374 __pagevec_lru_add(&pvec);
2375 __extent_read_full_page(tree, page, get_extent,
2376 &bio, 0);
2377 }
2378 page_cache_release(page);
2379 }
2380 if (pagevec_count(&pvec))
2381 __pagevec_lru_add(&pvec);
2382 BUG_ON(!list_empty(pages));
2383 if (bio)
2384 submit_one_bio(READ, bio, 0);
2385 return 0;
2386 }
2387 EXPORT_SYMBOL(extent_readpages);
2388
2389 /*
2390 * basic invalidatepage code, this waits on any locked or writeback
2391 * ranges corresponding to the page, and then deletes any extent state
2392 * records from the tree
2393 */
2394 int extent_invalidatepage(struct extent_io_tree *tree,
2395 struct page *page, unsigned long offset)
2396 {
2397 u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
2398 u64 end = start + PAGE_CACHE_SIZE - 1;
2399 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
2400
2401 start += (offset + blocksize -1) & ~(blocksize - 1);
2402 if (start > end)
2403 return 0;
2404
2405 lock_extent(tree, start, end, GFP_NOFS);
2406 wait_on_extent_writeback(tree, start, end);
2407 clear_extent_bit(tree, start, end,
2408 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC,
2409 1, 1, GFP_NOFS);
2410 return 0;
2411 }
2412 EXPORT_SYMBOL(extent_invalidatepage);
2413
2414 /*
2415 * simple commit_write call, set_range_dirty is used to mark both
2416 * the pages and the extent records as dirty
2417 */
2418 int extent_commit_write(struct extent_io_tree *tree,
2419 struct inode *inode, struct page *page,
2420 unsigned from, unsigned to)
2421 {
2422 loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
2423
2424 set_page_extent_mapped(page);
2425 set_page_dirty(page);
2426
2427 if (pos > inode->i_size) {
2428 i_size_write(inode, pos);
2429 mark_inode_dirty(inode);
2430 }
2431 return 0;
2432 }
2433 EXPORT_SYMBOL(extent_commit_write);
2434
2435 int extent_prepare_write(struct extent_io_tree *tree,
2436 struct inode *inode, struct page *page,
2437 unsigned from, unsigned to, get_extent_t *get_extent)
2438 {
2439 u64 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2440 u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
2441 u64 block_start;
2442 u64 orig_block_start;
2443 u64 block_end;
2444 u64 cur_end;
2445 struct extent_map *em;
2446 unsigned blocksize = 1 << inode->i_blkbits;
2447 size_t page_offset = 0;
2448 size_t block_off_start;
2449 size_t block_off_end;
2450 int err = 0;
2451 int iocount = 0;
2452 int ret = 0;
2453 int isnew;
2454
2455 set_page_extent_mapped(page);
2456
2457 block_start = (page_start + from) & ~((u64)blocksize - 1);
2458 block_end = (page_start + to - 1) | (blocksize - 1);
2459 orig_block_start = block_start;
2460
2461 lock_extent(tree, page_start, page_end, GFP_NOFS);
2462 while(block_start <= block_end) {
2463 em = get_extent(inode, page, page_offset, block_start,
2464 block_end - block_start + 1, 1);
2465 if (IS_ERR(em) || !em) {
2466 goto err;
2467 }
2468 cur_end = min(block_end, extent_map_end(em) - 1);
2469 block_off_start = block_start & (PAGE_CACHE_SIZE - 1);
2470 block_off_end = block_off_start + blocksize;
2471 isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS);
2472
2473 if (!PageUptodate(page) && isnew &&
2474 (block_off_end > to || block_off_start < from)) {
2475 void *kaddr;
2476
2477 kaddr = kmap_atomic(page, KM_USER0);
2478 if (block_off_end > to)
2479 memset(kaddr + to, 0, block_off_end - to);
2480 if (block_off_start < from)
2481 memset(kaddr + block_off_start, 0,
2482 from - block_off_start);
2483 flush_dcache_page(page);
2484 kunmap_atomic(kaddr, KM_USER0);
2485 }
2486 if ((em->block_start != EXTENT_MAP_HOLE &&
2487 em->block_start != EXTENT_MAP_INLINE) &&
2488 !isnew && !PageUptodate(page) &&
2489 (block_off_end > to || block_off_start < from) &&
2490 !test_range_bit(tree, block_start, cur_end,
2491 EXTENT_UPTODATE, 1)) {
2492 u64 sector;
2493 u64 extent_offset = block_start - em->start;
2494 size_t iosize;
2495 sector = (em->block_start + extent_offset) >> 9;
2496 iosize = (cur_end - block_start + blocksize) &
2497 ~((u64)blocksize - 1);
2498 /*
2499 * we've already got the extent locked, but we
2500 * need to split the state such that our end_bio
2501 * handler can clear the lock.
2502 */
2503 set_extent_bit(tree, block_start,
2504 block_start + iosize - 1,
2505 EXTENT_LOCKED, 0, NULL, GFP_NOFS);
2506 ret = submit_extent_page(READ, tree, page,
2507 sector, iosize, page_offset, em->bdev,
2508 NULL, 1,
2509 end_bio_extent_preparewrite, 0);
2510 iocount++;
2511 block_start = block_start + iosize;
2512 } else {
2513 set_extent_uptodate(tree, block_start, cur_end,
2514 GFP_NOFS);
2515 unlock_extent(tree, block_start, cur_end, GFP_NOFS);
2516 block_start = cur_end + 1;
2517 }
2518 page_offset = block_start & (PAGE_CACHE_SIZE - 1);
2519 free_extent_map(em);
2520 }
2521 if (iocount) {
2522 wait_extent_bit(tree, orig_block_start,
2523 block_end, EXTENT_LOCKED);
2524 }
2525 check_page_uptodate(tree, page);
2526 err:
2527 /* FIXME, zero out newly allocated blocks on error */
2528 return err;
2529 }
2530 EXPORT_SYMBOL(extent_prepare_write);
2531
2532 /*
2533 * a helper for releasepage, this tests for areas of the page that
2534 * are locked or under IO and drops the related state bits if it is safe
2535 * to drop the page.
2536 */
2537 int try_release_extent_state(struct extent_map_tree *map,
2538 struct extent_io_tree *tree, struct page *page,
2539 gfp_t mask)
2540 {
2541 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2542 u64 end = start + PAGE_CACHE_SIZE - 1;
2543 int ret = 1;
2544
2545 if (test_range_bit(tree, start, end, EXTENT_IOBITS, 0))
2546 ret = 0;
2547 else {
2548 if ((mask & GFP_NOFS) == GFP_NOFS)
2549 mask = GFP_NOFS;
2550 clear_extent_bit(tree, start, end, EXTENT_UPTODATE,
2551 1, 1, mask);
2552 }
2553 return ret;
2554 }
2555 EXPORT_SYMBOL(try_release_extent_state);
2556
2557 /*
2558 * a helper for releasepage. As long as there are no locked extents
2559 * in the range corresponding to the page, both state records and extent
2560 * map records are removed
2561 */
2562 int try_release_extent_mapping(struct extent_map_tree *map,
2563 struct extent_io_tree *tree, struct page *page,
2564 gfp_t mask)
2565 {
2566 struct extent_map *em;
2567 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2568 u64 end = start + PAGE_CACHE_SIZE - 1;
2569
2570 if ((mask & __GFP_WAIT) &&
2571 page->mapping->host->i_size > 16 * 1024 * 1024) {
2572 u64 len;
2573 while (start <= end) {
2574 len = end - start + 1;
2575 spin_lock(&map->lock);
2576 em = lookup_extent_mapping(map, start, len);
2577 if (!em || IS_ERR(em)) {
2578 spin_unlock(&map->lock);
2579 break;
2580 }
2581 if (em->start != start) {
2582 spin_unlock(&map->lock);
2583 free_extent_map(em);
2584 break;
2585 }
2586 if (!test_range_bit(tree, em->start,
2587 extent_map_end(em) - 1,
2588 EXTENT_LOCKED, 0)) {
2589 remove_extent_mapping(map, em);
2590 /* once for the rb tree */
2591 free_extent_map(em);
2592 }
2593 start = extent_map_end(em);
2594 spin_unlock(&map->lock);
2595
2596 /* once for us */
2597 free_extent_map(em);
2598 }
2599 }
2600 return try_release_extent_state(map, tree, page, mask);
2601 }
2602 EXPORT_SYMBOL(try_release_extent_mapping);
2603
2604 sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
2605 get_extent_t *get_extent)
2606 {
2607 struct inode *inode = mapping->host;
2608 u64 start = iblock << inode->i_blkbits;
2609 sector_t sector = 0;
2610 struct extent_map *em;
2611
2612 em = get_extent(inode, NULL, 0, start, (1 << inode->i_blkbits), 0);
2613 if (!em || IS_ERR(em))
2614 return 0;
2615
2616 if (em->block_start == EXTENT_MAP_INLINE ||
2617 em->block_start == EXTENT_MAP_HOLE)
2618 goto out;
2619
2620 sector = (em->block_start + start - em->start) >> inode->i_blkbits;
2621 out:
2622 free_extent_map(em);
2623 return sector;
2624 }
2625
2626 static int add_lru(struct extent_io_tree *tree, struct extent_buffer *eb)
2627 {
2628 if (list_empty(&eb->lru)) {
2629 extent_buffer_get(eb);
2630 list_add(&eb->lru, &tree->buffer_lru);
2631 tree->lru_size++;
2632 if (tree->lru_size >= BUFFER_LRU_MAX) {
2633 struct extent_buffer *rm;
2634 rm = list_entry(tree->buffer_lru.prev,
2635 struct extent_buffer, lru);
2636 tree->lru_size--;
2637 list_del_init(&rm->lru);
2638 free_extent_buffer(rm);
2639 }
2640 } else
2641 list_move(&eb->lru, &tree->buffer_lru);
2642 return 0;
2643 }
2644 static struct extent_buffer *find_lru(struct extent_io_tree *tree,
2645 u64 start, unsigned long len)
2646 {
2647 struct list_head *lru = &tree->buffer_lru;
2648 struct list_head *cur = lru->next;
2649 struct extent_buffer *eb;
2650
2651 if (list_empty(lru))
2652 return NULL;
2653
2654 do {
2655 eb = list_entry(cur, struct extent_buffer, lru);
2656 if (eb->start == start && eb->len == len) {
2657 extent_buffer_get(eb);
2658 return eb;
2659 }
2660 cur = cur->next;
2661 } while (cur != lru);
2662 return NULL;
2663 }
2664
2665 static inline unsigned long num_extent_pages(u64 start, u64 len)
2666 {
2667 return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
2668 (start >> PAGE_CACHE_SHIFT);
2669 }
2670
2671 static inline struct page *extent_buffer_page(struct extent_buffer *eb,
2672 unsigned long i)
2673 {
2674 struct page *p;
2675 struct address_space *mapping;
2676
2677 if (i == 0)
2678 return eb->first_page;
2679 i += eb->start >> PAGE_CACHE_SHIFT;
2680 mapping = eb->first_page->mapping;
2681 read_lock_irq(&mapping->tree_lock);
2682 p = radix_tree_lookup(&mapping->page_tree, i);
2683 read_unlock_irq(&mapping->tree_lock);
2684 return p;
2685 }
2686
2687 int release_extent_buffer_tail_pages(struct extent_buffer *eb)
2688 {
2689 unsigned long num_pages = num_extent_pages(eb->start, eb->len);
2690 struct page *page;
2691 unsigned long i;
2692
2693 if (num_pages == 1)
2694 return 0;
2695 for (i = 1; i < num_pages; i++) {
2696 page = extent_buffer_page(eb, i);
2697 page_cache_release(page);
2698 }
2699 return 0;
2700 }
2701
2702
2703 int invalidate_extent_lru(struct extent_io_tree *tree, u64 start,
2704 unsigned long len)
2705 {
2706 struct list_head *lru = &tree->buffer_lru;
2707 struct list_head *cur = lru->next;
2708 struct extent_buffer *eb;
2709 int found = 0;
2710
2711 spin_lock(&tree->lru_lock);
2712 if (list_empty(lru))
2713 goto out;
2714
2715 do {
2716 eb = list_entry(cur, struct extent_buffer, lru);
2717 if (eb->start <= start && eb->start + eb->len > start) {
2718 eb->flags &= ~EXTENT_UPTODATE;
2719 }
2720 cur = cur->next;
2721 } while (cur != lru);
2722 out:
2723 spin_unlock(&tree->lru_lock);
2724 return found;
2725 }
2726
2727 static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
2728 u64 start,
2729 unsigned long len,
2730 gfp_t mask)
2731 {
2732 struct extent_buffer *eb = NULL;
2733 unsigned long flags;
2734
2735 spin_lock(&tree->lru_lock);
2736 eb = find_lru(tree, start, len);
2737 spin_unlock(&tree->lru_lock);
2738 if (eb) {
2739 return eb;
2740 }
2741
2742 eb = kmem_cache_zalloc(extent_buffer_cache, mask);
2743 INIT_LIST_HEAD(&eb->lru);
2744 eb->start = start;
2745 eb->len = len;
2746 spin_lock_irqsave(&leak_lock, flags);
2747 list_add(&eb->leak_list, &buffers);
2748 spin_unlock_irqrestore(&leak_lock, flags);
2749 atomic_set(&eb->refs, 1);
2750
2751 return eb;
2752 }
2753
2754 static void __free_extent_buffer(struct extent_buffer *eb)
2755 {
2756 unsigned long flags;
2757 spin_lock_irqsave(&leak_lock, flags);
2758 list_del(&eb->leak_list);
2759 spin_unlock_irqrestore(&leak_lock, flags);
2760 kmem_cache_free(extent_buffer_cache, eb);
2761 }
2762
2763 struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
2764 u64 start, unsigned long len,
2765 struct page *page0,
2766 gfp_t mask)
2767 {
2768 unsigned long num_pages = num_extent_pages(start, len);
2769 unsigned long i;
2770 unsigned long index = start >> PAGE_CACHE_SHIFT;
2771 struct extent_buffer *eb;
2772 struct page *p;
2773 struct address_space *mapping = tree->mapping;
2774 int uptodate = 1;
2775
2776 eb = __alloc_extent_buffer(tree, start, len, mask);
2777 if (!eb)
2778 return NULL;
2779
2780 if (eb->flags & EXTENT_BUFFER_FILLED)
2781 goto lru_add;
2782
2783 if (page0) {
2784 eb->first_page = page0;
2785 i = 1;
2786 index++;
2787 page_cache_get(page0);
2788 mark_page_accessed(page0);
2789 set_page_extent_mapped(page0);
2790 set_page_extent_head(page0, len);
2791 uptodate = PageUptodate(page0);
2792 } else {
2793 i = 0;
2794 }
2795 for (; i < num_pages; i++, index++) {
2796 p = find_or_create_page(mapping, index, mask | __GFP_HIGHMEM);
2797 if (!p) {
2798 WARN_ON(1);
2799 goto fail;
2800 }
2801 set_page_extent_mapped(p);
2802 mark_page_accessed(p);
2803 if (i == 0) {
2804 eb->first_page = p;
2805 set_page_extent_head(p, len);
2806 } else {
2807 set_page_private(p, EXTENT_PAGE_PRIVATE);
2808 }
2809 if (!PageUptodate(p))
2810 uptodate = 0;
2811 unlock_page(p);
2812 }
2813 if (uptodate)
2814 eb->flags |= EXTENT_UPTODATE;
2815 eb->flags |= EXTENT_BUFFER_FILLED;
2816
2817 lru_add:
2818 spin_lock(&tree->lru_lock);
2819 add_lru(tree, eb);
2820 spin_unlock(&tree->lru_lock);
2821 return eb;
2822
2823 fail:
2824 spin_lock(&tree->lru_lock);
2825 list_del_init(&eb->lru);
2826 spin_unlock(&tree->lru_lock);
2827 if (!atomic_dec_and_test(&eb->refs))
2828 return NULL;
2829 for (index = 1; index < i; index++) {
2830 page_cache_release(extent_buffer_page(eb, index));
2831 }
2832 if (i > 0)
2833 page_cache_release(extent_buffer_page(eb, 0));
2834 __free_extent_buffer(eb);
2835 return NULL;
2836 }
2837 EXPORT_SYMBOL(alloc_extent_buffer);
2838
2839 struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
2840 u64 start, unsigned long len,
2841 gfp_t mask)
2842 {
2843 unsigned long num_pages = num_extent_pages(start, len);
2844 unsigned long i;
2845 unsigned long index = start >> PAGE_CACHE_SHIFT;
2846 struct extent_buffer *eb;
2847 struct page *p;
2848 struct address_space *mapping = tree->mapping;
2849 int uptodate = 1;
2850
2851 eb = __alloc_extent_buffer(tree, start, len, mask);
2852 if (!eb)
2853 return NULL;
2854
2855 if (eb->flags & EXTENT_BUFFER_FILLED)
2856 goto lru_add;
2857
2858 for (i = 0; i < num_pages; i++, index++) {
2859 p = find_get_page(mapping, index);
2860 if (!p) {
2861 goto fail;
2862 }
2863 if (TestSetPageLocked(p)) {
2864 page_cache_release(p);
2865 goto fail;
2866 }
2867
2868 set_page_extent_mapped(p);
2869 mark_page_accessed(p);
2870
2871 if (i == 0) {
2872 eb->first_page = p;
2873 set_page_extent_head(p, len);
2874 } else {
2875 set_page_private(p, EXTENT_PAGE_PRIVATE);
2876 }
2877
2878 if (!PageUptodate(p))
2879 uptodate = 0;
2880 unlock_page(p);
2881 }
2882 if (uptodate)
2883 eb->flags |= EXTENT_UPTODATE;
2884 eb->flags |= EXTENT_BUFFER_FILLED;
2885
2886 lru_add:
2887 spin_lock(&tree->lru_lock);
2888 add_lru(tree, eb);
2889 spin_unlock(&tree->lru_lock);
2890 return eb;
2891 fail:
2892 spin_lock(&tree->lru_lock);
2893 list_del_init(&eb->lru);
2894 spin_unlock(&tree->lru_lock);
2895 if (!atomic_dec_and_test(&eb->refs))
2896 return NULL;
2897 for (index = 1; index < i; index++) {
2898 page_cache_release(extent_buffer_page(eb, index));
2899 }
2900 if (i > 0)
2901 page_cache_release(extent_buffer_page(eb, 0));
2902 __free_extent_buffer(eb);
2903 return NULL;
2904 }
2905 EXPORT_SYMBOL(find_extent_buffer);
2906
2907 void free_extent_buffer(struct extent_buffer *eb)
2908 {
2909 unsigned long i;
2910 unsigned long num_pages;
2911
2912 if (!eb)
2913 return;
2914
2915 if (!atomic_dec_and_test(&eb->refs))
2916 return;
2917
2918 WARN_ON(!list_empty(&eb->lru));
2919 num_pages = num_extent_pages(eb->start, eb->len);
2920
2921 for (i = 1; i < num_pages; i++) {
2922 page_cache_release(extent_buffer_page(eb, i));
2923 }
2924 page_cache_release(extent_buffer_page(eb, 0));
2925 __free_extent_buffer(eb);
2926 }
2927 EXPORT_SYMBOL(free_extent_buffer);
2928
2929 int clear_extent_buffer_dirty(struct extent_io_tree *tree,
2930 struct extent_buffer *eb)
2931 {
2932 int set;
2933 unsigned long i;
2934 unsigned long num_pages;
2935 struct page *page;
2936
2937 u64 start = eb->start;
2938 u64 end = start + eb->len - 1;
2939
2940 set = clear_extent_dirty(tree, start, end, GFP_NOFS);
2941 num_pages = num_extent_pages(eb->start, eb->len);
2942
2943 for (i = 0; i < num_pages; i++) {
2944 page = extent_buffer_page(eb, i);
2945 if (i == 0)
2946 set_page_extent_head(page, eb->len);
2947 else
2948 set_page_private(page, EXTENT_PAGE_PRIVATE);
2949
2950 /*
2951 * if we're on the last page or the first page and the
2952 * block isn't aligned on a page boundary, do extra checks
2953 * to make sure we don't clean page that is partially dirty
2954 */
2955 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
2956 ((i == num_pages - 1) &&
2957 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
2958 start = (u64)page->index << PAGE_CACHE_SHIFT;
2959 end = start + PAGE_CACHE_SIZE - 1;
2960 if (test_range_bit(tree, start, end,
2961 EXTENT_DIRTY, 0)) {
2962 continue;
2963 }
2964 }
2965 clear_page_dirty_for_io(page);
2966 read_lock_irq(&page->mapping->tree_lock);
2967 if (!PageDirty(page)) {
2968 radix_tree_tag_clear(&page->mapping->page_tree,
2969 page_index(page),
2970 PAGECACHE_TAG_DIRTY);
2971 }
2972 read_unlock_irq(&page->mapping->tree_lock);
2973 }
2974 return 0;
2975 }
2976 EXPORT_SYMBOL(clear_extent_buffer_dirty);
2977
2978 int wait_on_extent_buffer_writeback(struct extent_io_tree *tree,
2979 struct extent_buffer *eb)
2980 {
2981 return wait_on_extent_writeback(tree, eb->start,
2982 eb->start + eb->len - 1);
2983 }
2984 EXPORT_SYMBOL(wait_on_extent_buffer_writeback);
2985
2986 int set_extent_buffer_dirty(struct extent_io_tree *tree,
2987 struct extent_buffer *eb)
2988 {
2989 unsigned long i;
2990 unsigned long num_pages;
2991
2992 num_pages = num_extent_pages(eb->start, eb->len);
2993 for (i = 0; i < num_pages; i++) {
2994 struct page *page = extent_buffer_page(eb, i);
2995 /* writepage may need to do something special for the
2996 * first page, we have to make sure page->private is
2997 * properly set. releasepage may drop page->private
2998 * on us if the page isn't already dirty.
2999 */
3000 if (i == 0) {
3001 set_page_extent_head(page, eb->len);
3002 } else if (PagePrivate(page) &&
3003 page->private != EXTENT_PAGE_PRIVATE) {
3004 set_page_extent_mapped(page);
3005 }
3006 __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3007 }
3008 return set_extent_dirty(tree, eb->start,
3009 eb->start + eb->len - 1, GFP_NOFS);
3010 }
3011 EXPORT_SYMBOL(set_extent_buffer_dirty);
3012
3013 int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3014 struct extent_buffer *eb)
3015 {
3016 unsigned long i;
3017 struct page *page;
3018 unsigned long num_pages;
3019
3020 num_pages = num_extent_pages(eb->start, eb->len);
3021 eb->flags &= ~EXTENT_UPTODATE;
3022
3023 clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3024 GFP_NOFS);
3025 for (i = 0; i < num_pages; i++) {
3026 page = extent_buffer_page(eb, i);
3027 ClearPageUptodate(page);
3028 }
3029 return 0;
3030 }
3031
3032 int set_extent_buffer_uptodate(struct extent_io_tree *tree,
3033 struct extent_buffer *eb)
3034 {
3035 unsigned long i;
3036 struct page *page;
3037 unsigned long num_pages;
3038
3039 num_pages = num_extent_pages(eb->start, eb->len);
3040
3041 set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3042 GFP_NOFS);
3043 for (i = 0; i < num_pages; i++) {
3044 page = extent_buffer_page(eb, i);
3045 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3046 ((i == num_pages - 1) &&
3047 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3048 check_page_uptodate(tree, page);
3049 continue;
3050 }
3051 SetPageUptodate(page);
3052 }
3053 return 0;
3054 }
3055 EXPORT_SYMBOL(set_extent_buffer_uptodate);
3056
3057 int extent_range_uptodate(struct extent_io_tree *tree,
3058 u64 start, u64 end)
3059 {
3060 struct page *page;
3061 int ret;
3062 int pg_uptodate = 1;
3063 int uptodate;
3064 unsigned long index;
3065
3066 ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1);
3067 if (ret)
3068 return 1;
3069 while(start <= end) {
3070 index = start >> PAGE_CACHE_SHIFT;
3071 page = find_get_page(tree->mapping, index);
3072 uptodate = PageUptodate(page);
3073 page_cache_release(page);
3074 if (!uptodate) {
3075 pg_uptodate = 0;
3076 break;
3077 }
3078 start += PAGE_CACHE_SIZE;
3079 }
3080 return pg_uptodate;
3081 }
3082
3083 int extent_buffer_uptodate(struct extent_io_tree *tree,
3084 struct extent_buffer *eb)
3085 {
3086 int ret = 0;
3087 unsigned long num_pages;
3088 unsigned long i;
3089 struct page *page;
3090 int pg_uptodate = 1;
3091
3092 if (eb->flags & EXTENT_UPTODATE)
3093 return 1;
3094
3095 ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3096 EXTENT_UPTODATE, 1);
3097 if (ret)
3098 return ret;
3099
3100 num_pages = num_extent_pages(eb->start, eb->len);
3101 for (i = 0; i < num_pages; i++) {
3102 page = extent_buffer_page(eb, i);
3103 if (!PageUptodate(page)) {
3104 pg_uptodate = 0;
3105 break;
3106 }
3107 }
3108 return pg_uptodate;
3109 }
3110 EXPORT_SYMBOL(extent_buffer_uptodate);
3111
3112 int read_extent_buffer_pages(struct extent_io_tree *tree,
3113 struct extent_buffer *eb,
3114 u64 start, int wait,
3115 get_extent_t *get_extent, int mirror_num)
3116 {
3117 unsigned long i;
3118 unsigned long start_i;
3119 struct page *page;
3120 int err;
3121 int ret = 0;
3122 int locked_pages = 0;
3123 int all_uptodate = 1;
3124 int inc_all_pages = 0;
3125 unsigned long num_pages;
3126 struct bio *bio = NULL;
3127
3128 if (eb->flags & EXTENT_UPTODATE)
3129 return 0;
3130
3131 if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3132 EXTENT_UPTODATE, 1)) {
3133 return 0;
3134 }
3135
3136 if (start) {
3137 WARN_ON(start < eb->start);
3138 start_i = (start >> PAGE_CACHE_SHIFT) -
3139 (eb->start >> PAGE_CACHE_SHIFT);
3140 } else {
3141 start_i = 0;
3142 }
3143
3144 num_pages = num_extent_pages(eb->start, eb->len);
3145 for (i = start_i; i < num_pages; i++) {
3146 page = extent_buffer_page(eb, i);
3147 if (!wait) {
3148 if (TestSetPageLocked(page))
3149 goto unlock_exit;
3150 } else {
3151 lock_page(page);
3152 }
3153 locked_pages++;
3154 if (!PageUptodate(page)) {
3155 all_uptodate = 0;
3156 }
3157 }
3158 if (all_uptodate) {
3159 if (start_i == 0)
3160 eb->flags |= EXTENT_UPTODATE;
3161 goto unlock_exit;
3162 }
3163
3164 for (i = start_i; i < num_pages; i++) {
3165 page = extent_buffer_page(eb, i);
3166 if (inc_all_pages)
3167 page_cache_get(page);
3168 if (!PageUptodate(page)) {
3169 if (start_i == 0)
3170 inc_all_pages = 1;
3171 ClearPageError(page);
3172 err = __extent_read_full_page(tree, page,
3173 get_extent, &bio,
3174 mirror_num);
3175 if (err) {
3176 ret = err;
3177 }
3178 } else {
3179 unlock_page(page);
3180 }
3181 }
3182
3183 if (bio)
3184 submit_one_bio(READ, bio, mirror_num);
3185
3186 if (ret || !wait) {
3187 return ret;
3188 }
3189 for (i = start_i; i < num_pages; i++) {
3190 page = extent_buffer_page(eb, i);
3191 wait_on_page_locked(page);
3192 if (!PageUptodate(page)) {
3193 ret = -EIO;
3194 }
3195 }
3196 if (!ret)
3197 eb->flags |= EXTENT_UPTODATE;
3198 return ret;
3199
3200 unlock_exit:
3201 i = start_i;
3202 while(locked_pages > 0) {
3203 page = extent_buffer_page(eb, i);
3204 i++;
3205 unlock_page(page);
3206 locked_pages--;
3207 }
3208 return ret;
3209 }
3210 EXPORT_SYMBOL(read_extent_buffer_pages);
3211
3212 void read_extent_buffer(struct extent_buffer *eb, void *dstv,
3213 unsigned long start,
3214 unsigned long len)
3215 {
3216 size_t cur;
3217 size_t offset;
3218 struct page *page;
3219 char *kaddr;
3220 char *dst = (char *)dstv;
3221 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3222 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3223
3224 WARN_ON(start > eb->len);
3225 WARN_ON(start + len > eb->start + eb->len);
3226
3227 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3228
3229 while(len > 0) {
3230 page = extent_buffer_page(eb, i);
3231
3232 cur = min(len, (PAGE_CACHE_SIZE - offset));
3233 kaddr = kmap_atomic(page, KM_USER1);
3234 memcpy(dst, kaddr + offset, cur);
3235 kunmap_atomic(kaddr, KM_USER1);
3236
3237 dst += cur;
3238 len -= cur;
3239 offset = 0;
3240 i++;
3241 }
3242 }
3243 EXPORT_SYMBOL(read_extent_buffer);
3244
3245 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
3246 unsigned long min_len, char **token, char **map,
3247 unsigned long *map_start,
3248 unsigned long *map_len, int km)
3249 {
3250 size_t offset = start & (PAGE_CACHE_SIZE - 1);
3251 char *kaddr;
3252 struct page *p;
3253 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3254 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3255 unsigned long end_i = (start_offset + start + min_len - 1) >>
3256 PAGE_CACHE_SHIFT;
3257
3258 if (i != end_i)
3259 return -EINVAL;
3260
3261 if (i == 0) {
3262 offset = start_offset;
3263 *map_start = 0;
3264 } else {
3265 offset = 0;
3266 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
3267 }
3268 if (start + min_len > eb->len) {
3269 printk("bad mapping eb start %Lu len %lu, wanted %lu %lu\n", eb->start, eb->len, start, min_len);
3270 WARN_ON(1);
3271 }
3272
3273 p = extent_buffer_page(eb, i);
3274 kaddr = kmap_atomic(p, km);
3275 *token = kaddr;
3276 *map = kaddr + offset;
3277 *map_len = PAGE_CACHE_SIZE - offset;
3278 return 0;
3279 }
3280 EXPORT_SYMBOL(map_private_extent_buffer);
3281
3282 int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
3283 unsigned long min_len,
3284 char **token, char **map,
3285 unsigned long *map_start,
3286 unsigned long *map_len, int km)
3287 {
3288 int err;
3289 int save = 0;
3290 if (eb->map_token) {
3291 unmap_extent_buffer(eb, eb->map_token, km);
3292 eb->map_token = NULL;
3293 save = 1;
3294 }
3295 err = map_private_extent_buffer(eb, start, min_len, token, map,
3296 map_start, map_len, km);
3297 if (!err && save) {
3298 eb->map_token = *token;
3299 eb->kaddr = *map;
3300 eb->map_start = *map_start;
3301 eb->map_len = *map_len;
3302 }
3303 return err;
3304 }
3305 EXPORT_SYMBOL(map_extent_buffer);
3306
3307 void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km)
3308 {
3309 kunmap_atomic(token, km);
3310 }
3311 EXPORT_SYMBOL(unmap_extent_buffer);
3312
3313 int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
3314 unsigned long start,
3315 unsigned long len)
3316 {
3317 size_t cur;
3318 size_t offset;
3319 struct page *page;
3320 char *kaddr;
3321 char *ptr = (char *)ptrv;
3322 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3323 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3324 int ret = 0;
3325
3326 WARN_ON(start > eb->len);
3327 WARN_ON(start + len > eb->start + eb->len);
3328
3329 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3330
3331 while(len > 0) {
3332 page = extent_buffer_page(eb, i);
3333
3334 cur = min(len, (PAGE_CACHE_SIZE - offset));
3335
3336 kaddr = kmap_atomic(page, KM_USER0);
3337 ret = memcmp(ptr, kaddr + offset, cur);
3338 kunmap_atomic(kaddr, KM_USER0);
3339 if (ret)
3340 break;
3341
3342 ptr += cur;
3343 len -= cur;
3344 offset = 0;
3345 i++;
3346 }
3347 return ret;
3348 }
3349 EXPORT_SYMBOL(memcmp_extent_buffer);
3350
3351 void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
3352 unsigned long start, unsigned long len)
3353 {
3354 size_t cur;
3355 size_t offset;
3356 struct page *page;
3357 char *kaddr;
3358 char *src = (char *)srcv;
3359 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3360 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3361
3362 WARN_ON(start > eb->len);
3363 WARN_ON(start + len > eb->start + eb->len);
3364
3365 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3366
3367 while(len > 0) {
3368 page = extent_buffer_page(eb, i);
3369 WARN_ON(!PageUptodate(page));
3370
3371 cur = min(len, PAGE_CACHE_SIZE - offset);
3372 kaddr = kmap_atomic(page, KM_USER1);
3373 memcpy(kaddr + offset, src, cur);
3374 kunmap_atomic(kaddr, KM_USER1);
3375
3376 src += cur;
3377 len -= cur;
3378 offset = 0;
3379 i++;
3380 }
3381 }
3382 EXPORT_SYMBOL(write_extent_buffer);
3383
3384 void memset_extent_buffer(struct extent_buffer *eb, char c,
3385 unsigned long start, unsigned long len)
3386 {
3387 size_t cur;
3388 size_t offset;
3389 struct page *page;
3390 char *kaddr;
3391 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3392 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3393
3394 WARN_ON(start > eb->len);
3395 WARN_ON(start + len > eb->start + eb->len);
3396
3397 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3398
3399 while(len > 0) {
3400 page = extent_buffer_page(eb, i);
3401 WARN_ON(!PageUptodate(page));
3402
3403 cur = min(len, PAGE_CACHE_SIZE - offset);
3404 kaddr = kmap_atomic(page, KM_USER0);
3405 memset(kaddr + offset, c, cur);
3406 kunmap_atomic(kaddr, KM_USER0);
3407
3408 len -= cur;
3409 offset = 0;
3410 i++;
3411 }
3412 }
3413 EXPORT_SYMBOL(memset_extent_buffer);
3414
3415 void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
3416 unsigned long dst_offset, unsigned long src_offset,
3417 unsigned long len)
3418 {
3419 u64 dst_len = dst->len;
3420 size_t cur;
3421 size_t offset;
3422 struct page *page;
3423 char *kaddr;
3424 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3425 unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3426
3427 WARN_ON(src->len != dst_len);
3428
3429 offset = (start_offset + dst_offset) &
3430 ((unsigned long)PAGE_CACHE_SIZE - 1);
3431
3432 while(len > 0) {
3433 page = extent_buffer_page(dst, i);
3434 WARN_ON(!PageUptodate(page));
3435
3436 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
3437
3438 kaddr = kmap_atomic(page, KM_USER0);
3439 read_extent_buffer(src, kaddr + offset, src_offset, cur);
3440 kunmap_atomic(kaddr, KM_USER0);
3441
3442 src_offset += cur;
3443 len -= cur;
3444 offset = 0;
3445 i++;
3446 }
3447 }
3448 EXPORT_SYMBOL(copy_extent_buffer);
3449
3450 static void move_pages(struct page *dst_page, struct page *src_page,
3451 unsigned long dst_off, unsigned long src_off,
3452 unsigned long len)
3453 {
3454 char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
3455 if (dst_page == src_page) {
3456 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
3457 } else {
3458 char *src_kaddr = kmap_atomic(src_page, KM_USER1);
3459 char *p = dst_kaddr + dst_off + len;
3460 char *s = src_kaddr + src_off + len;
3461
3462 while (len--)
3463 *--p = *--s;
3464
3465 kunmap_atomic(src_kaddr, KM_USER1);
3466 }
3467 kunmap_atomic(dst_kaddr, KM_USER0);
3468 }
3469
3470 static void copy_pages(struct page *dst_page, struct page *src_page,
3471 unsigned long dst_off, unsigned long src_off,
3472 unsigned long len)
3473 {
3474 char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
3475 char *src_kaddr;
3476
3477 if (dst_page != src_page)
3478 src_kaddr = kmap_atomic(src_page, KM_USER1);
3479 else
3480 src_kaddr = dst_kaddr;
3481
3482 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
3483 kunmap_atomic(dst_kaddr, KM_USER0);
3484 if (dst_page != src_page)
3485 kunmap_atomic(src_kaddr, KM_USER1);
3486 }
3487
3488 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3489 unsigned long src_offset, unsigned long len)
3490 {
3491 size_t cur;
3492 size_t dst_off_in_page;
3493 size_t src_off_in_page;
3494 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3495 unsigned long dst_i;
3496 unsigned long src_i;
3497
3498 if (src_offset + len > dst->len) {
3499 printk("memmove bogus src_offset %lu move len %lu len %lu\n",
3500 src_offset, len, dst->len);
3501 BUG_ON(1);
3502 }
3503 if (dst_offset + len > dst->len) {
3504 printk("memmove bogus dst_offset %lu move len %lu len %lu\n",
3505 dst_offset, len, dst->len);
3506 BUG_ON(1);
3507 }
3508
3509 while(len > 0) {
3510 dst_off_in_page = (start_offset + dst_offset) &
3511 ((unsigned long)PAGE_CACHE_SIZE - 1);
3512 src_off_in_page = (start_offset + src_offset) &
3513 ((unsigned long)PAGE_CACHE_SIZE - 1);
3514
3515 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3516 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
3517
3518 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
3519 src_off_in_page));
3520 cur = min_t(unsigned long, cur,
3521 (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
3522
3523 copy_pages(extent_buffer_page(dst, dst_i),
3524 extent_buffer_page(dst, src_i),
3525 dst_off_in_page, src_off_in_page, cur);
3526
3527 src_offset += cur;
3528 dst_offset += cur;
3529 len -= cur;
3530 }
3531 }
3532 EXPORT_SYMBOL(memcpy_extent_buffer);
3533
3534 void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3535 unsigned long src_offset, unsigned long len)
3536 {
3537 size_t cur;
3538 size_t dst_off_in_page;
3539 size_t src_off_in_page;
3540 unsigned long dst_end = dst_offset + len - 1;
3541 unsigned long src_end = src_offset + len - 1;
3542 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3543 unsigned long dst_i;
3544 unsigned long src_i;
3545
3546 if (src_offset + len > dst->len) {
3547 printk("memmove bogus src_offset %lu move len %lu len %lu\n",
3548 src_offset, len, dst->len);
3549 BUG_ON(1);
3550 }
3551 if (dst_offset + len > dst->len) {
3552 printk("memmove bogus dst_offset %lu move len %lu len %lu\n",
3553 dst_offset, len, dst->len);
3554 BUG_ON(1);
3555 }
3556 if (dst_offset < src_offset) {
3557 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
3558 return;
3559 }
3560 while(len > 0) {
3561 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
3562 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
3563
3564 dst_off_in_page = (start_offset + dst_end) &
3565 ((unsigned long)PAGE_CACHE_SIZE - 1);
3566 src_off_in_page = (start_offset + src_end) &
3567 ((unsigned long)PAGE_CACHE_SIZE - 1);
3568
3569 cur = min_t(unsigned long, len, src_off_in_page + 1);
3570 cur = min(cur, dst_off_in_page + 1);
3571 move_pages(extent_buffer_page(dst, dst_i),
3572 extent_buffer_page(dst, src_i),
3573 dst_off_in_page - cur + 1,
3574 src_off_in_page - cur + 1, cur);
3575
3576 dst_end -= cur;
3577 src_end -= cur;
3578 len -= cur;
3579 }
3580 }
3581 EXPORT_SYMBOL(memmove_extent_buffer);
Linux kernel - Deliverables
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