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Btrfs: Don't allow releasepage to succeed if EXTENT_ORDERED is set
[mirror_ubuntu-zesty-kernel.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,
2546 EXTENT_IOBITS | EXTENT_ORDERED, 0))
2547 ret = 0;
2548 else {
2549 if ((mask & GFP_NOFS) == GFP_NOFS)
2550 mask = GFP_NOFS;
2551 clear_extent_bit(tree, start, end, EXTENT_UPTODATE,
2552 1, 1, mask);
2553 }
2554 return ret;
2555 }
2556 EXPORT_SYMBOL(try_release_extent_state);
2557
2558 /*
2559 * a helper for releasepage. As long as there are no locked extents
2560 * in the range corresponding to the page, both state records and extent
2561 * map records are removed
2562 */
2563 int try_release_extent_mapping(struct extent_map_tree *map,
2564 struct extent_io_tree *tree, struct page *page,
2565 gfp_t mask)
2566 {
2567 struct extent_map *em;
2568 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
2569 u64 end = start + PAGE_CACHE_SIZE - 1;
2570
2571 if ((mask & __GFP_WAIT) &&
2572 page->mapping->host->i_size > 16 * 1024 * 1024) {
2573 u64 len;
2574 while (start <= end) {
2575 len = end - start + 1;
2576 spin_lock(&map->lock);
2577 em = lookup_extent_mapping(map, start, len);
2578 if (!em || IS_ERR(em)) {
2579 spin_unlock(&map->lock);
2580 break;
2581 }
2582 if (em->start != start) {
2583 spin_unlock(&map->lock);
2584 free_extent_map(em);
2585 break;
2586 }
2587 if (!test_range_bit(tree, em->start,
2588 extent_map_end(em) - 1,
2589 EXTENT_LOCKED, 0)) {
2590 remove_extent_mapping(map, em);
2591 /* once for the rb tree */
2592 free_extent_map(em);
2593 }
2594 start = extent_map_end(em);
2595 spin_unlock(&map->lock);
2596
2597 /* once for us */
2598 free_extent_map(em);
2599 }
2600 }
2601 return try_release_extent_state(map, tree, page, mask);
2602 }
2603 EXPORT_SYMBOL(try_release_extent_mapping);
2604
2605 sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
2606 get_extent_t *get_extent)
2607 {
2608 struct inode *inode = mapping->host;
2609 u64 start = iblock << inode->i_blkbits;
2610 sector_t sector = 0;
2611 struct extent_map *em;
2612
2613 em = get_extent(inode, NULL, 0, start, (1 << inode->i_blkbits), 0);
2614 if (!em || IS_ERR(em))
2615 return 0;
2616
2617 if (em->block_start == EXTENT_MAP_INLINE ||
2618 em->block_start == EXTENT_MAP_HOLE)
2619 goto out;
2620
2621 sector = (em->block_start + start - em->start) >> inode->i_blkbits;
2622 out:
2623 free_extent_map(em);
2624 return sector;
2625 }
2626
2627 static int add_lru(struct extent_io_tree *tree, struct extent_buffer *eb)
2628 {
2629 if (list_empty(&eb->lru)) {
2630 extent_buffer_get(eb);
2631 list_add(&eb->lru, &tree->buffer_lru);
2632 tree->lru_size++;
2633 if (tree->lru_size >= BUFFER_LRU_MAX) {
2634 struct extent_buffer *rm;
2635 rm = list_entry(tree->buffer_lru.prev,
2636 struct extent_buffer, lru);
2637 tree->lru_size--;
2638 list_del_init(&rm->lru);
2639 free_extent_buffer(rm);
2640 }
2641 } else
2642 list_move(&eb->lru, &tree->buffer_lru);
2643 return 0;
2644 }
2645 static struct extent_buffer *find_lru(struct extent_io_tree *tree,
2646 u64 start, unsigned long len)
2647 {
2648 struct list_head *lru = &tree->buffer_lru;
2649 struct list_head *cur = lru->next;
2650 struct extent_buffer *eb;
2651
2652 if (list_empty(lru))
2653 return NULL;
2654
2655 do {
2656 eb = list_entry(cur, struct extent_buffer, lru);
2657 if (eb->start == start && eb->len == len) {
2658 extent_buffer_get(eb);
2659 return eb;
2660 }
2661 cur = cur->next;
2662 } while (cur != lru);
2663 return NULL;
2664 }
2665
2666 static inline unsigned long num_extent_pages(u64 start, u64 len)
2667 {
2668 return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
2669 (start >> PAGE_CACHE_SHIFT);
2670 }
2671
2672 static inline struct page *extent_buffer_page(struct extent_buffer *eb,
2673 unsigned long i)
2674 {
2675 struct page *p;
2676 struct address_space *mapping;
2677
2678 if (i == 0)
2679 return eb->first_page;
2680 i += eb->start >> PAGE_CACHE_SHIFT;
2681 mapping = eb->first_page->mapping;
2682 read_lock_irq(&mapping->tree_lock);
2683 p = radix_tree_lookup(&mapping->page_tree, i);
2684 read_unlock_irq(&mapping->tree_lock);
2685 return p;
2686 }
2687
2688 int release_extent_buffer_tail_pages(struct extent_buffer *eb)
2689 {
2690 unsigned long num_pages = num_extent_pages(eb->start, eb->len);
2691 struct page *page;
2692 unsigned long i;
2693
2694 if (num_pages == 1)
2695 return 0;
2696 for (i = 1; i < num_pages; i++) {
2697 page = extent_buffer_page(eb, i);
2698 page_cache_release(page);
2699 }
2700 return 0;
2701 }
2702
2703
2704 int invalidate_extent_lru(struct extent_io_tree *tree, u64 start,
2705 unsigned long len)
2706 {
2707 struct list_head *lru = &tree->buffer_lru;
2708 struct list_head *cur = lru->next;
2709 struct extent_buffer *eb;
2710 int found = 0;
2711
2712 spin_lock(&tree->lru_lock);
2713 if (list_empty(lru))
2714 goto out;
2715
2716 do {
2717 eb = list_entry(cur, struct extent_buffer, lru);
2718 if (eb->start <= start && eb->start + eb->len > start) {
2719 eb->flags &= ~EXTENT_UPTODATE;
2720 }
2721 cur = cur->next;
2722 } while (cur != lru);
2723 out:
2724 spin_unlock(&tree->lru_lock);
2725 return found;
2726 }
2727
2728 static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
2729 u64 start,
2730 unsigned long len,
2731 gfp_t mask)
2732 {
2733 struct extent_buffer *eb = NULL;
2734 unsigned long flags;
2735
2736 spin_lock(&tree->lru_lock);
2737 eb = find_lru(tree, start, len);
2738 spin_unlock(&tree->lru_lock);
2739 if (eb) {
2740 return eb;
2741 }
2742
2743 eb = kmem_cache_zalloc(extent_buffer_cache, mask);
2744 INIT_LIST_HEAD(&eb->lru);
2745 eb->start = start;
2746 eb->len = len;
2747 spin_lock_irqsave(&leak_lock, flags);
2748 list_add(&eb->leak_list, &buffers);
2749 spin_unlock_irqrestore(&leak_lock, flags);
2750 atomic_set(&eb->refs, 1);
2751
2752 return eb;
2753 }
2754
2755 static void __free_extent_buffer(struct extent_buffer *eb)
2756 {
2757 unsigned long flags;
2758 spin_lock_irqsave(&leak_lock, flags);
2759 list_del(&eb->leak_list);
2760 spin_unlock_irqrestore(&leak_lock, flags);
2761 kmem_cache_free(extent_buffer_cache, eb);
2762 }
2763
2764 struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
2765 u64 start, unsigned long len,
2766 struct page *page0,
2767 gfp_t mask)
2768 {
2769 unsigned long num_pages = num_extent_pages(start, len);
2770 unsigned long i;
2771 unsigned long index = start >> PAGE_CACHE_SHIFT;
2772 struct extent_buffer *eb;
2773 struct page *p;
2774 struct address_space *mapping = tree->mapping;
2775 int uptodate = 1;
2776
2777 eb = __alloc_extent_buffer(tree, start, len, mask);
2778 if (!eb)
2779 return NULL;
2780
2781 if (eb->flags & EXTENT_BUFFER_FILLED)
2782 goto lru_add;
2783
2784 if (page0) {
2785 eb->first_page = page0;
2786 i = 1;
2787 index++;
2788 page_cache_get(page0);
2789 mark_page_accessed(page0);
2790 set_page_extent_mapped(page0);
2791 set_page_extent_head(page0, len);
2792 uptodate = PageUptodate(page0);
2793 } else {
2794 i = 0;
2795 }
2796 for (; i < num_pages; i++, index++) {
2797 p = find_or_create_page(mapping, index, mask | __GFP_HIGHMEM);
2798 if (!p) {
2799 WARN_ON(1);
2800 goto fail;
2801 }
2802 set_page_extent_mapped(p);
2803 mark_page_accessed(p);
2804 if (i == 0) {
2805 eb->first_page = p;
2806 set_page_extent_head(p, len);
2807 } else {
2808 set_page_private(p, EXTENT_PAGE_PRIVATE);
2809 }
2810 if (!PageUptodate(p))
2811 uptodate = 0;
2812 unlock_page(p);
2813 }
2814 if (uptodate)
2815 eb->flags |= EXTENT_UPTODATE;
2816 eb->flags |= EXTENT_BUFFER_FILLED;
2817
2818 lru_add:
2819 spin_lock(&tree->lru_lock);
2820 add_lru(tree, eb);
2821 spin_unlock(&tree->lru_lock);
2822 return eb;
2823
2824 fail:
2825 spin_lock(&tree->lru_lock);
2826 list_del_init(&eb->lru);
2827 spin_unlock(&tree->lru_lock);
2828 if (!atomic_dec_and_test(&eb->refs))
2829 return NULL;
2830 for (index = 1; index < i; index++) {
2831 page_cache_release(extent_buffer_page(eb, index));
2832 }
2833 if (i > 0)
2834 page_cache_release(extent_buffer_page(eb, 0));
2835 __free_extent_buffer(eb);
2836 return NULL;
2837 }
2838 EXPORT_SYMBOL(alloc_extent_buffer);
2839
2840 struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
2841 u64 start, unsigned long len,
2842 gfp_t mask)
2843 {
2844 unsigned long num_pages = num_extent_pages(start, len);
2845 unsigned long i;
2846 unsigned long index = start >> PAGE_CACHE_SHIFT;
2847 struct extent_buffer *eb;
2848 struct page *p;
2849 struct address_space *mapping = tree->mapping;
2850 int uptodate = 1;
2851
2852 eb = __alloc_extent_buffer(tree, start, len, mask);
2853 if (!eb)
2854 return NULL;
2855
2856 if (eb->flags & EXTENT_BUFFER_FILLED)
2857 goto lru_add;
2858
2859 for (i = 0; i < num_pages; i++, index++) {
2860 p = find_get_page(mapping, index);
2861 if (!p) {
2862 goto fail;
2863 }
2864 if (TestSetPageLocked(p)) {
2865 page_cache_release(p);
2866 goto fail;
2867 }
2868
2869 set_page_extent_mapped(p);
2870 mark_page_accessed(p);
2871
2872 if (i == 0) {
2873 eb->first_page = p;
2874 set_page_extent_head(p, len);
2875 } else {
2876 set_page_private(p, EXTENT_PAGE_PRIVATE);
2877 }
2878
2879 if (!PageUptodate(p))
2880 uptodate = 0;
2881 unlock_page(p);
2882 }
2883 if (uptodate)
2884 eb->flags |= EXTENT_UPTODATE;
2885 eb->flags |= EXTENT_BUFFER_FILLED;
2886
2887 lru_add:
2888 spin_lock(&tree->lru_lock);
2889 add_lru(tree, eb);
2890 spin_unlock(&tree->lru_lock);
2891 return eb;
2892 fail:
2893 spin_lock(&tree->lru_lock);
2894 list_del_init(&eb->lru);
2895 spin_unlock(&tree->lru_lock);
2896 if (!atomic_dec_and_test(&eb->refs))
2897 return NULL;
2898 for (index = 1; index < i; index++) {
2899 page_cache_release(extent_buffer_page(eb, index));
2900 }
2901 if (i > 0)
2902 page_cache_release(extent_buffer_page(eb, 0));
2903 __free_extent_buffer(eb);
2904 return NULL;
2905 }
2906 EXPORT_SYMBOL(find_extent_buffer);
2907
2908 void free_extent_buffer(struct extent_buffer *eb)
2909 {
2910 unsigned long i;
2911 unsigned long num_pages;
2912
2913 if (!eb)
2914 return;
2915
2916 if (!atomic_dec_and_test(&eb->refs))
2917 return;
2918
2919 WARN_ON(!list_empty(&eb->lru));
2920 num_pages = num_extent_pages(eb->start, eb->len);
2921
2922 for (i = 1; i < num_pages; i++) {
2923 page_cache_release(extent_buffer_page(eb, i));
2924 }
2925 page_cache_release(extent_buffer_page(eb, 0));
2926 __free_extent_buffer(eb);
2927 }
2928 EXPORT_SYMBOL(free_extent_buffer);
2929
2930 int clear_extent_buffer_dirty(struct extent_io_tree *tree,
2931 struct extent_buffer *eb)
2932 {
2933 int set;
2934 unsigned long i;
2935 unsigned long num_pages;
2936 struct page *page;
2937
2938 u64 start = eb->start;
2939 u64 end = start + eb->len - 1;
2940
2941 set = clear_extent_dirty(tree, start, end, GFP_NOFS);
2942 num_pages = num_extent_pages(eb->start, eb->len);
2943
2944 for (i = 0; i < num_pages; i++) {
2945 page = extent_buffer_page(eb, i);
2946 if (i == 0)
2947 set_page_extent_head(page, eb->len);
2948 else
2949 set_page_private(page, EXTENT_PAGE_PRIVATE);
2950
2951 /*
2952 * if we're on the last page or the first page and the
2953 * block isn't aligned on a page boundary, do extra checks
2954 * to make sure we don't clean page that is partially dirty
2955 */
2956 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
2957 ((i == num_pages - 1) &&
2958 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
2959 start = (u64)page->index << PAGE_CACHE_SHIFT;
2960 end = start + PAGE_CACHE_SIZE - 1;
2961 if (test_range_bit(tree, start, end,
2962 EXTENT_DIRTY, 0)) {
2963 continue;
2964 }
2965 }
2966 clear_page_dirty_for_io(page);
2967 read_lock_irq(&page->mapping->tree_lock);
2968 if (!PageDirty(page)) {
2969 radix_tree_tag_clear(&page->mapping->page_tree,
2970 page_index(page),
2971 PAGECACHE_TAG_DIRTY);
2972 }
2973 read_unlock_irq(&page->mapping->tree_lock);
2974 }
2975 return 0;
2976 }
2977 EXPORT_SYMBOL(clear_extent_buffer_dirty);
2978
2979 int wait_on_extent_buffer_writeback(struct extent_io_tree *tree,
2980 struct extent_buffer *eb)
2981 {
2982 return wait_on_extent_writeback(tree, eb->start,
2983 eb->start + eb->len - 1);
2984 }
2985 EXPORT_SYMBOL(wait_on_extent_buffer_writeback);
2986
2987 int set_extent_buffer_dirty(struct extent_io_tree *tree,
2988 struct extent_buffer *eb)
2989 {
2990 unsigned long i;
2991 unsigned long num_pages;
2992
2993 num_pages = num_extent_pages(eb->start, eb->len);
2994 for (i = 0; i < num_pages; i++) {
2995 struct page *page = extent_buffer_page(eb, i);
2996 /* writepage may need to do something special for the
2997 * first page, we have to make sure page->private is
2998 * properly set. releasepage may drop page->private
2999 * on us if the page isn't already dirty.
3000 */
3001 if (i == 0) {
3002 set_page_extent_head(page, eb->len);
3003 } else if (PagePrivate(page) &&
3004 page->private != EXTENT_PAGE_PRIVATE) {
3005 set_page_extent_mapped(page);
3006 }
3007 __set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3008 }
3009 return set_extent_dirty(tree, eb->start,
3010 eb->start + eb->len - 1, GFP_NOFS);
3011 }
3012 EXPORT_SYMBOL(set_extent_buffer_dirty);
3013
3014 int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3015 struct extent_buffer *eb)
3016 {
3017 unsigned long i;
3018 struct page *page;
3019 unsigned long num_pages;
3020
3021 num_pages = num_extent_pages(eb->start, eb->len);
3022 eb->flags &= ~EXTENT_UPTODATE;
3023
3024 clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3025 GFP_NOFS);
3026 for (i = 0; i < num_pages; i++) {
3027 page = extent_buffer_page(eb, i);
3028 ClearPageUptodate(page);
3029 }
3030 return 0;
3031 }
3032
3033 int set_extent_buffer_uptodate(struct extent_io_tree *tree,
3034 struct extent_buffer *eb)
3035 {
3036 unsigned long i;
3037 struct page *page;
3038 unsigned long num_pages;
3039
3040 num_pages = num_extent_pages(eb->start, eb->len);
3041
3042 set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3043 GFP_NOFS);
3044 for (i = 0; i < num_pages; i++) {
3045 page = extent_buffer_page(eb, i);
3046 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
3047 ((i == num_pages - 1) &&
3048 ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
3049 check_page_uptodate(tree, page);
3050 continue;
3051 }
3052 SetPageUptodate(page);
3053 }
3054 return 0;
3055 }
3056 EXPORT_SYMBOL(set_extent_buffer_uptodate);
3057
3058 int extent_range_uptodate(struct extent_io_tree *tree,
3059 u64 start, u64 end)
3060 {
3061 struct page *page;
3062 int ret;
3063 int pg_uptodate = 1;
3064 int uptodate;
3065 unsigned long index;
3066
3067 ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1);
3068 if (ret)
3069 return 1;
3070 while(start <= end) {
3071 index = start >> PAGE_CACHE_SHIFT;
3072 page = find_get_page(tree->mapping, index);
3073 uptodate = PageUptodate(page);
3074 page_cache_release(page);
3075 if (!uptodate) {
3076 pg_uptodate = 0;
3077 break;
3078 }
3079 start += PAGE_CACHE_SIZE;
3080 }
3081 return pg_uptodate;
3082 }
3083
3084 int extent_buffer_uptodate(struct extent_io_tree *tree,
3085 struct extent_buffer *eb)
3086 {
3087 int ret = 0;
3088 unsigned long num_pages;
3089 unsigned long i;
3090 struct page *page;
3091 int pg_uptodate = 1;
3092
3093 if (eb->flags & EXTENT_UPTODATE)
3094 return 1;
3095
3096 ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3097 EXTENT_UPTODATE, 1);
3098 if (ret)
3099 return ret;
3100
3101 num_pages = num_extent_pages(eb->start, eb->len);
3102 for (i = 0; i < num_pages; i++) {
3103 page = extent_buffer_page(eb, i);
3104 if (!PageUptodate(page)) {
3105 pg_uptodate = 0;
3106 break;
3107 }
3108 }
3109 return pg_uptodate;
3110 }
3111 EXPORT_SYMBOL(extent_buffer_uptodate);
3112
3113 int read_extent_buffer_pages(struct extent_io_tree *tree,
3114 struct extent_buffer *eb,
3115 u64 start, int wait,
3116 get_extent_t *get_extent, int mirror_num)
3117 {
3118 unsigned long i;
3119 unsigned long start_i;
3120 struct page *page;
3121 int err;
3122 int ret = 0;
3123 int locked_pages = 0;
3124 int all_uptodate = 1;
3125 int inc_all_pages = 0;
3126 unsigned long num_pages;
3127 struct bio *bio = NULL;
3128
3129 if (eb->flags & EXTENT_UPTODATE)
3130 return 0;
3131
3132 if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3133 EXTENT_UPTODATE, 1)) {
3134 return 0;
3135 }
3136
3137 if (start) {
3138 WARN_ON(start < eb->start);
3139 start_i = (start >> PAGE_CACHE_SHIFT) -
3140 (eb->start >> PAGE_CACHE_SHIFT);
3141 } else {
3142 start_i = 0;
3143 }
3144
3145 num_pages = num_extent_pages(eb->start, eb->len);
3146 for (i = start_i; i < num_pages; i++) {
3147 page = extent_buffer_page(eb, i);
3148 if (!wait) {
3149 if (TestSetPageLocked(page))
3150 goto unlock_exit;
3151 } else {
3152 lock_page(page);
3153 }
3154 locked_pages++;
3155 if (!PageUptodate(page)) {
3156 all_uptodate = 0;
3157 }
3158 }
3159 if (all_uptodate) {
3160 if (start_i == 0)
3161 eb->flags |= EXTENT_UPTODATE;
3162 goto unlock_exit;
3163 }
3164
3165 for (i = start_i; i < num_pages; i++) {
3166 page = extent_buffer_page(eb, i);
3167 if (inc_all_pages)
3168 page_cache_get(page);
3169 if (!PageUptodate(page)) {
3170 if (start_i == 0)
3171 inc_all_pages = 1;
3172 ClearPageError(page);
3173 err = __extent_read_full_page(tree, page,
3174 get_extent, &bio,
3175 mirror_num);
3176 if (err) {
3177 ret = err;
3178 }
3179 } else {
3180 unlock_page(page);
3181 }
3182 }
3183
3184 if (bio)
3185 submit_one_bio(READ, bio, mirror_num);
3186
3187 if (ret || !wait) {
3188 return ret;
3189 }
3190 for (i = start_i; i < num_pages; i++) {
3191 page = extent_buffer_page(eb, i);
3192 wait_on_page_locked(page);
3193 if (!PageUptodate(page)) {
3194 ret = -EIO;
3195 }
3196 }
3197 if (!ret)
3198 eb->flags |= EXTENT_UPTODATE;
3199 return ret;
3200
3201 unlock_exit:
3202 i = start_i;
3203 while(locked_pages > 0) {
3204 page = extent_buffer_page(eb, i);
3205 i++;
3206 unlock_page(page);
3207 locked_pages--;
3208 }
3209 return ret;
3210 }
3211 EXPORT_SYMBOL(read_extent_buffer_pages);
3212
3213 void read_extent_buffer(struct extent_buffer *eb, void *dstv,
3214 unsigned long start,
3215 unsigned long len)
3216 {
3217 size_t cur;
3218 size_t offset;
3219 struct page *page;
3220 char *kaddr;
3221 char *dst = (char *)dstv;
3222 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3223 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3224
3225 WARN_ON(start > eb->len);
3226 WARN_ON(start + len > eb->start + eb->len);
3227
3228 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3229
3230 while(len > 0) {
3231 page = extent_buffer_page(eb, i);
3232
3233 cur = min(len, (PAGE_CACHE_SIZE - offset));
3234 kaddr = kmap_atomic(page, KM_USER1);
3235 memcpy(dst, kaddr + offset, cur);
3236 kunmap_atomic(kaddr, KM_USER1);
3237
3238 dst += cur;
3239 len -= cur;
3240 offset = 0;
3241 i++;
3242 }
3243 }
3244 EXPORT_SYMBOL(read_extent_buffer);
3245
3246 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
3247 unsigned long min_len, char **token, char **map,
3248 unsigned long *map_start,
3249 unsigned long *map_len, int km)
3250 {
3251 size_t offset = start & (PAGE_CACHE_SIZE - 1);
3252 char *kaddr;
3253 struct page *p;
3254 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3255 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3256 unsigned long end_i = (start_offset + start + min_len - 1) >>
3257 PAGE_CACHE_SHIFT;
3258
3259 if (i != end_i)
3260 return -EINVAL;
3261
3262 if (i == 0) {
3263 offset = start_offset;
3264 *map_start = 0;
3265 } else {
3266 offset = 0;
3267 *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
3268 }
3269 if (start + min_len > eb->len) {
3270 printk("bad mapping eb start %Lu len %lu, wanted %lu %lu\n", eb->start, eb->len, start, min_len);
3271 WARN_ON(1);
3272 }
3273
3274 p = extent_buffer_page(eb, i);
3275 kaddr = kmap_atomic(p, km);
3276 *token = kaddr;
3277 *map = kaddr + offset;
3278 *map_len = PAGE_CACHE_SIZE - offset;
3279 return 0;
3280 }
3281 EXPORT_SYMBOL(map_private_extent_buffer);
3282
3283 int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
3284 unsigned long min_len,
3285 char **token, char **map,
3286 unsigned long *map_start,
3287 unsigned long *map_len, int km)
3288 {
3289 int err;
3290 int save = 0;
3291 if (eb->map_token) {
3292 unmap_extent_buffer(eb, eb->map_token, km);
3293 eb->map_token = NULL;
3294 save = 1;
3295 }
3296 err = map_private_extent_buffer(eb, start, min_len, token, map,
3297 map_start, map_len, km);
3298 if (!err && save) {
3299 eb->map_token = *token;
3300 eb->kaddr = *map;
3301 eb->map_start = *map_start;
3302 eb->map_len = *map_len;
3303 }
3304 return err;
3305 }
3306 EXPORT_SYMBOL(map_extent_buffer);
3307
3308 void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km)
3309 {
3310 kunmap_atomic(token, km);
3311 }
3312 EXPORT_SYMBOL(unmap_extent_buffer);
3313
3314 int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
3315 unsigned long start,
3316 unsigned long len)
3317 {
3318 size_t cur;
3319 size_t offset;
3320 struct page *page;
3321 char *kaddr;
3322 char *ptr = (char *)ptrv;
3323 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3324 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3325 int ret = 0;
3326
3327 WARN_ON(start > eb->len);
3328 WARN_ON(start + len > eb->start + eb->len);
3329
3330 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3331
3332 while(len > 0) {
3333 page = extent_buffer_page(eb, i);
3334
3335 cur = min(len, (PAGE_CACHE_SIZE - offset));
3336
3337 kaddr = kmap_atomic(page, KM_USER0);
3338 ret = memcmp(ptr, kaddr + offset, cur);
3339 kunmap_atomic(kaddr, KM_USER0);
3340 if (ret)
3341 break;
3342
3343 ptr += cur;
3344 len -= cur;
3345 offset = 0;
3346 i++;
3347 }
3348 return ret;
3349 }
3350 EXPORT_SYMBOL(memcmp_extent_buffer);
3351
3352 void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
3353 unsigned long start, unsigned long len)
3354 {
3355 size_t cur;
3356 size_t offset;
3357 struct page *page;
3358 char *kaddr;
3359 char *src = (char *)srcv;
3360 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3361 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3362
3363 WARN_ON(start > eb->len);
3364 WARN_ON(start + len > eb->start + eb->len);
3365
3366 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3367
3368 while(len > 0) {
3369 page = extent_buffer_page(eb, i);
3370 WARN_ON(!PageUptodate(page));
3371
3372 cur = min(len, PAGE_CACHE_SIZE - offset);
3373 kaddr = kmap_atomic(page, KM_USER1);
3374 memcpy(kaddr + offset, src, cur);
3375 kunmap_atomic(kaddr, KM_USER1);
3376
3377 src += cur;
3378 len -= cur;
3379 offset = 0;
3380 i++;
3381 }
3382 }
3383 EXPORT_SYMBOL(write_extent_buffer);
3384
3385 void memset_extent_buffer(struct extent_buffer *eb, char c,
3386 unsigned long start, unsigned long len)
3387 {
3388 size_t cur;
3389 size_t offset;
3390 struct page *page;
3391 char *kaddr;
3392 size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
3393 unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
3394
3395 WARN_ON(start > eb->len);
3396 WARN_ON(start + len > eb->start + eb->len);
3397
3398 offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
3399
3400 while(len > 0) {
3401 page = extent_buffer_page(eb, i);
3402 WARN_ON(!PageUptodate(page));
3403
3404 cur = min(len, PAGE_CACHE_SIZE - offset);
3405 kaddr = kmap_atomic(page, KM_USER0);
3406 memset(kaddr + offset, c, cur);
3407 kunmap_atomic(kaddr, KM_USER0);
3408
3409 len -= cur;
3410 offset = 0;
3411 i++;
3412 }
3413 }
3414 EXPORT_SYMBOL(memset_extent_buffer);
3415
3416 void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
3417 unsigned long dst_offset, unsigned long src_offset,
3418 unsigned long len)
3419 {
3420 u64 dst_len = dst->len;
3421 size_t cur;
3422 size_t offset;
3423 struct page *page;
3424 char *kaddr;
3425 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3426 unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3427
3428 WARN_ON(src->len != dst_len);
3429
3430 offset = (start_offset + dst_offset) &
3431 ((unsigned long)PAGE_CACHE_SIZE - 1);
3432
3433 while(len > 0) {
3434 page = extent_buffer_page(dst, i);
3435 WARN_ON(!PageUptodate(page));
3436
3437 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
3438
3439 kaddr = kmap_atomic(page, KM_USER0);
3440 read_extent_buffer(src, kaddr + offset, src_offset, cur);
3441 kunmap_atomic(kaddr, KM_USER0);
3442
3443 src_offset += cur;
3444 len -= cur;
3445 offset = 0;
3446 i++;
3447 }
3448 }
3449 EXPORT_SYMBOL(copy_extent_buffer);
3450
3451 static void move_pages(struct page *dst_page, struct page *src_page,
3452 unsigned long dst_off, unsigned long src_off,
3453 unsigned long len)
3454 {
3455 char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
3456 if (dst_page == src_page) {
3457 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
3458 } else {
3459 char *src_kaddr = kmap_atomic(src_page, KM_USER1);
3460 char *p = dst_kaddr + dst_off + len;
3461 char *s = src_kaddr + src_off + len;
3462
3463 while (len--)
3464 *--p = *--s;
3465
3466 kunmap_atomic(src_kaddr, KM_USER1);
3467 }
3468 kunmap_atomic(dst_kaddr, KM_USER0);
3469 }
3470
3471 static void copy_pages(struct page *dst_page, struct page *src_page,
3472 unsigned long dst_off, unsigned long src_off,
3473 unsigned long len)
3474 {
3475 char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
3476 char *src_kaddr;
3477
3478 if (dst_page != src_page)
3479 src_kaddr = kmap_atomic(src_page, KM_USER1);
3480 else
3481 src_kaddr = dst_kaddr;
3482
3483 memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
3484 kunmap_atomic(dst_kaddr, KM_USER0);
3485 if (dst_page != src_page)
3486 kunmap_atomic(src_kaddr, KM_USER1);
3487 }
3488
3489 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3490 unsigned long src_offset, unsigned long len)
3491 {
3492 size_t cur;
3493 size_t dst_off_in_page;
3494 size_t src_off_in_page;
3495 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3496 unsigned long dst_i;
3497 unsigned long src_i;
3498
3499 if (src_offset + len > dst->len) {
3500 printk("memmove bogus src_offset %lu move len %lu len %lu\n",
3501 src_offset, len, dst->len);
3502 BUG_ON(1);
3503 }
3504 if (dst_offset + len > dst->len) {
3505 printk("memmove bogus dst_offset %lu move len %lu len %lu\n",
3506 dst_offset, len, dst->len);
3507 BUG_ON(1);
3508 }
3509
3510 while(len > 0) {
3511 dst_off_in_page = (start_offset + dst_offset) &
3512 ((unsigned long)PAGE_CACHE_SIZE - 1);
3513 src_off_in_page = (start_offset + src_offset) &
3514 ((unsigned long)PAGE_CACHE_SIZE - 1);
3515
3516 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
3517 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
3518
3519 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
3520 src_off_in_page));
3521 cur = min_t(unsigned long, cur,
3522 (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));
3523
3524 copy_pages(extent_buffer_page(dst, dst_i),
3525 extent_buffer_page(dst, src_i),
3526 dst_off_in_page, src_off_in_page, cur);
3527
3528 src_offset += cur;
3529 dst_offset += cur;
3530 len -= cur;
3531 }
3532 }
3533 EXPORT_SYMBOL(memcpy_extent_buffer);
3534
3535 void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
3536 unsigned long src_offset, unsigned long len)
3537 {
3538 size_t cur;
3539 size_t dst_off_in_page;
3540 size_t src_off_in_page;
3541 unsigned long dst_end = dst_offset + len - 1;
3542 unsigned long src_end = src_offset + len - 1;
3543 size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
3544 unsigned long dst_i;
3545 unsigned long src_i;
3546
3547 if (src_offset + len > dst->len) {
3548 printk("memmove bogus src_offset %lu move len %lu len %lu\n",
3549 src_offset, len, dst->len);
3550 BUG_ON(1);
3551 }
3552 if (dst_offset + len > dst->len) {
3553 printk("memmove bogus dst_offset %lu move len %lu len %lu\n",
3554 dst_offset, len, dst->len);
3555 BUG_ON(1);
3556 }
3557 if (dst_offset < src_offset) {
3558 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
3559 return;
3560 }
3561 while(len > 0) {
3562 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
3563 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
3564
3565 dst_off_in_page = (start_offset + dst_end) &
3566 ((unsigned long)PAGE_CACHE_SIZE - 1);
3567 src_off_in_page = (start_offset + src_end) &
3568 ((unsigned long)PAGE_CACHE_SIZE - 1);
3569
3570 cur = min_t(unsigned long, len, src_off_in_page + 1);
3571 cur = min(cur, dst_off_in_page + 1);
3572 move_pages(extent_buffer_page(dst, dst_i),
3573 extent_buffer_page(dst, src_i),
3574 dst_off_in_page - cur + 1,
3575 src_off_in_page - cur + 1, cur);
3576
3577 dst_end -= cur;
3578 src_end -= cur;
3579 len -= cur;
3580 }
3581 }
3582 EXPORT_SYMBOL(memmove_extent_buffer);
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