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authorChris Mason <chris.mason@oracle.com>2007-08-27 16:49:44 -0400
committerDavid Woodhouse <dwmw2@hera.kernel.org>2007-08-27 16:49:44 -0400
commita52d9a8033c454cd9b4697cfafb467509fc1693f (patch)
tree83d8bbf2df29598ea9c60498fadf5990262a11c8 /fs/btrfs/extent_map.c
parent83df7c1d8b885e216c68c3f0469bec9b93666b74 (diff)
Btrfs: Extent based page cache code. This uses an rbtree of extents and tests
instead of buffer heads. Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/extent_map.c')
-rw-r--r--fs/btrfs/extent_map.c1656
1 files changed, 1656 insertions, 0 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
new file mode 100644
index 000000000000..d378edf0964e
--- /dev/null
+++ b/fs/btrfs/extent_map.c
@@ -0,0 +1,1656 @@
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 "extent_map.h"
12
13static struct kmem_cache *extent_map_cache;
14static struct kmem_cache *extent_state_cache;
15
16struct tree_entry {
17 u64 start;
18 u64 end;
19 int in_tree;
20 struct rb_node rb_node;
21};
22
23/* bits for the extent state */
24#define EXTENT_DIRTY 1
25#define EXTENT_WRITEBACK (1 << 1)
26#define EXTENT_UPTODATE (1 << 2)
27#define EXTENT_LOCKED (1 << 3)
28#define EXTENT_NEW (1 << 4)
29#define EXTENT_DELALLOC (1 << 5)
30
31#define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
32
33static LIST_HEAD(all_states);
34spinlock_t state_lock = SPIN_LOCK_UNLOCKED;
35
36void __init extent_map_init(void)
37{
38 extent_map_cache = kmem_cache_create("extent_map",
39 sizeof(struct extent_map), 0,
40 SLAB_RECLAIM_ACCOUNT |
41 SLAB_DESTROY_BY_RCU,
42 NULL);
43 extent_state_cache = kmem_cache_create("extent_state",
44 sizeof(struct extent_state), 0,
45 SLAB_RECLAIM_ACCOUNT |
46 SLAB_DESTROY_BY_RCU,
47 NULL);
48}
49
50void __exit extent_map_exit(void)
51{
52 while(!list_empty(&all_states)) {
53 struct extent_state *state;
54 struct list_head *cur = all_states.next;
55 state = list_entry(cur, struct extent_state, list);
56 printk("found leaked state %Lu %Lu state %d in_tree %d\n",
57 state->start, state->end, state->state, state->in_tree);
58 list_del(&state->list);
59 kfree(state);
60 }
61 if (extent_map_cache)
62 kmem_cache_destroy(extent_map_cache);
63 if (extent_state_cache)
64 kmem_cache_destroy(extent_state_cache);
65}
66
67void extent_map_tree_init(struct extent_map_tree *tree,
68 struct address_space *mapping, gfp_t mask)
69{
70 tree->map.rb_node = NULL;
71 tree->state.rb_node = NULL;
72 rwlock_init(&tree->lock);
73 tree->mapping = mapping;
74}
75EXPORT_SYMBOL(extent_map_tree_init);
76
77struct extent_map *alloc_extent_map(gfp_t mask)
78{
79 struct extent_map *em;
80 em = kmem_cache_alloc(extent_map_cache, mask);
81 if (!em || IS_ERR(em))
82 return em;
83 em->in_tree = 0;
84 atomic_set(&em->refs, 1);
85 return em;
86}
87EXPORT_SYMBOL(alloc_extent_map);
88
89void free_extent_map(struct extent_map *em)
90{
91 if (atomic_dec_and_test(&em->refs)) {
92 WARN_ON(em->in_tree);
93 kmem_cache_free(extent_map_cache, em);
94 }
95}
96EXPORT_SYMBOL(free_extent_map);
97
98
99struct extent_state *alloc_extent_state(gfp_t mask)
100{
101 struct extent_state *state;
102 state = kmem_cache_alloc(extent_state_cache, mask);
103 if (!state || IS_ERR(state))
104 return state;
105 state->state = 0;
106 state->in_tree = 0;
107 atomic_set(&state->refs, 1);
108 init_waitqueue_head(&state->wq);
109 spin_lock_irq(&state_lock);
110 list_add(&state->list, &all_states);
111 spin_unlock_irq(&state_lock);
112 return state;
113}
114EXPORT_SYMBOL(alloc_extent_state);
115
116void free_extent_state(struct extent_state *state)
117{
118 if (atomic_dec_and_test(&state->refs)) {
119 WARN_ON(state->in_tree);
120 spin_lock_irq(&state_lock);
121 list_del_init(&state->list);
122 spin_unlock_irq(&state_lock);
123 kmem_cache_free(extent_state_cache, state);
124 }
125}
126EXPORT_SYMBOL(free_extent_state);
127
128static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
129 struct rb_node *node)
130{
131 struct rb_node ** p = &root->rb_node;
132 struct rb_node * parent = NULL;
133 struct tree_entry *entry;
134
135 while(*p) {
136 parent = *p;
137 entry = rb_entry(parent, struct tree_entry, rb_node);
138
139 if (offset < entry->start)
140 p = &(*p)->rb_left;
141 else if (offset > entry->end)
142 p = &(*p)->rb_right;
143 else
144 return parent;
145 }
146
147 entry = rb_entry(node, struct tree_entry, rb_node);
148 entry->in_tree = 1;
149 rb_link_node(node, parent, p);
150 rb_insert_color(node, root);
151 return NULL;
152}
153
154static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
155 struct rb_node **prev_ret)
156{
157 struct rb_node * n = root->rb_node;
158 struct rb_node *prev = NULL;
159 struct tree_entry *entry;
160 struct tree_entry *prev_entry = NULL;
161
162 while(n) {
163 entry = rb_entry(n, struct tree_entry, rb_node);
164 prev = n;
165 prev_entry = entry;
166
167 if (offset < entry->start)
168 n = n->rb_left;
169 else if (offset > entry->end)
170 n = n->rb_right;
171 else
172 return n;
173 }
174 if (!prev_ret)
175 return NULL;
176 while(prev && offset > prev_entry->end) {
177 prev = rb_next(prev);
178 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
179 }
180 *prev_ret = prev;
181 return NULL;
182}
183
184static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
185{
186 struct rb_node *prev;
187 struct rb_node *ret;
188 ret = __tree_search(root, offset, &prev);
189 if (!ret)
190 return prev;
191 return ret;
192}
193
194static int tree_delete(struct rb_root *root, u64 offset)
195{
196 struct rb_node *node;
197 struct tree_entry *entry;
198
199 node = __tree_search(root, offset, NULL);
200 if (!node)
201 return -ENOENT;
202 entry = rb_entry(node, struct tree_entry, rb_node);
203 entry->in_tree = 0;
204 rb_erase(node, root);
205 return 0;
206}
207
208/*
209 * add_extent_mapping tries a simple backward merge with existing
210 * mappings. The extent_map struct passed in will be inserted into
211 * the tree directly (no copies made, just a reference taken).
212 */
213int add_extent_mapping(struct extent_map_tree *tree,
214 struct extent_map *em)
215{
216 int ret = 0;
217 struct extent_map *prev = NULL;
218 struct rb_node *rb;
219
220 write_lock_irq(&tree->lock);
221 rb = tree_insert(&tree->map, em->end, &em->rb_node);
222 if (rb) {
223 prev = rb_entry(rb, struct extent_map, rb_node);
224 printk("found extent map %Lu %Lu on insert of %Lu %Lu\n", prev->start, prev->end, em->start, em->end);
225 ret = -EEXIST;
226 goto out;
227 }
228 atomic_inc(&em->refs);
229 if (em->start != 0) {
230 rb = rb_prev(&em->rb_node);
231 if (rb)
232 prev = rb_entry(rb, struct extent_map, rb_node);
233 if (prev && prev->end + 1 == em->start &&
234 ((em->block_start == 0 && prev->block_start == 0) ||
235 (em->block_start == prev->block_end + 1))) {
236 em->start = prev->start;
237 em->block_start = prev->block_start;
238 rb_erase(&prev->rb_node, &tree->map);
239 prev->in_tree = 0;
240 free_extent_map(prev);
241 }
242 }
243out:
244 write_unlock_irq(&tree->lock);
245 return ret;
246}
247EXPORT_SYMBOL(add_extent_mapping);
248
249/*
250 * lookup_extent_mapping returns the first extent_map struct in the
251 * tree that intersects the [start, end] (inclusive) range. There may
252 * be additional objects in the tree that intersect, so check the object
253 * returned carefully to make sure you don't need additional lookups.
254 */
255struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
256 u64 start, u64 end)
257{
258 struct extent_map *em;
259 struct rb_node *rb_node;
260
261 read_lock_irq(&tree->lock);
262 rb_node = tree_search(&tree->map, start);
263 if (!rb_node) {
264 em = NULL;
265 goto out;
266 }
267 if (IS_ERR(rb_node)) {
268 em = ERR_PTR(PTR_ERR(rb_node));
269 goto out;
270 }
271 em = rb_entry(rb_node, struct extent_map, rb_node);
272 if (em->end < start || em->start > end) {
273 em = NULL;
274 goto out;
275 }
276 atomic_inc(&em->refs);
277out:
278 read_unlock_irq(&tree->lock);
279 return em;
280}
281EXPORT_SYMBOL(lookup_extent_mapping);
282
283/*
284 * removes an extent_map struct from the tree. No reference counts are
285 * dropped, and no checks are done to see if the range is in use
286 */
287int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
288{
289 int ret;
290
291 write_lock_irq(&tree->lock);
292 ret = tree_delete(&tree->map, em->end);
293 write_unlock_irq(&tree->lock);
294 return ret;
295}
296EXPORT_SYMBOL(remove_extent_mapping);
297
298/*
299 * utility function to look for merge candidates inside a given range.
300 * Any extents with matching state are merged together into a single
301 * extent in the tree. Extents with EXTENT_IO in their state field
302 * are not merged because the end_io handlers need to be able to do
303 * operations on them without sleeping (or doing allocations/splits).
304 *
305 * This should be called with the tree lock held.
306 */
307static int merge_state(struct extent_map_tree *tree,
308 struct extent_state *state)
309{
310 struct extent_state *other;
311 struct rb_node *other_node;
312
313 if (state->state & EXTENT_IOBITS)
314 return 0;
315
316 other_node = rb_prev(&state->rb_node);
317 if (other_node) {
318 other = rb_entry(other_node, struct extent_state, rb_node);
319 if (other->end == state->start - 1 &&
320 other->state == state->state) {
321 state->start = other->start;
322 other->in_tree = 0;
323 rb_erase(&other->rb_node, &tree->state);
324 free_extent_state(other);
325 }
326 }
327 other_node = rb_next(&state->rb_node);
328 if (other_node) {
329 other = rb_entry(other_node, struct extent_state, rb_node);
330 if (other->start == state->end + 1 &&
331 other->state == state->state) {
332 other->start = state->start;
333 state->in_tree = 0;
334 rb_erase(&state->rb_node, &tree->state);
335 free_extent_state(state);
336 }
337 }
338 return 0;
339}
340
341/*
342 * insert an extent_state struct into the tree. 'bits' are set on the
343 * struct before it is inserted.
344 *
345 * This may return -EEXIST if the extent is already there, in which case the
346 * state struct is freed.
347 *
348 * The tree lock is not taken internally. This is a utility function and
349 * probably isn't what you want to call (see set/clear_extent_bit).
350 */
351static int insert_state(struct extent_map_tree *tree,
352 struct extent_state *state, u64 start, u64 end,
353 int bits)
354{
355 struct rb_node *node;
356
357 if (end < start) {
358 printk("end < start %Lu %Lu\n", end, start);
359 WARN_ON(1);
360 }
361 state->state |= bits;
362 state->start = start;
363 state->end = end;
364 if ((end & 4095) == 0) {
365 printk("insert state %Lu %Lu strange end\n", start, end);
366 WARN_ON(1);
367 }
368 node = tree_insert(&tree->state, end, &state->rb_node);
369 if (node) {
370 struct extent_state *found;
371 found = rb_entry(node, struct extent_state, rb_node);
372printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, start, end);
373 free_extent_state(state);
374 return -EEXIST;
375 }
376 merge_state(tree, state);
377 return 0;
378}
379
380/*
381 * split a given extent state struct in two, inserting the preallocated
382 * struct 'prealloc' as the newly created second half. 'split' indicates an
383 * offset inside 'orig' where it should be split.
384 *
385 * Before calling,
386 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
387 * are two extent state structs in the tree:
388 * prealloc: [orig->start, split - 1]
389 * orig: [ split, orig->end ]
390 *
391 * The tree locks are not taken by this function. They need to be held
392 * by the caller.
393 */
394static int split_state(struct extent_map_tree *tree, struct extent_state *orig,
395 struct extent_state *prealloc, u64 split)
396{
397 struct rb_node *node;
398 prealloc->start = orig->start;
399 prealloc->end = split - 1;
400 prealloc->state = orig->state;
401 orig->start = split;
402 if ((prealloc->end & 4095) == 0) {
403 printk("insert state %Lu %Lu strange end\n", prealloc->start,
404 prealloc->end);
405 WARN_ON(1);
406 }
407 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
408 if (node) {
409 struct extent_state *found;
410 found = rb_entry(node, struct extent_state, rb_node);
411printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, prealloc->start, prealloc->end);
412 free_extent_state(prealloc);
413 return -EEXIST;
414 }
415 return 0;
416}
417
418/*
419 * utility function to clear some bits in an extent state struct.
420 * it will optionally wake up any one waiting on this state (wake == 1), or
421 * forcibly remove the state from the tree (delete == 1).
422 *
423 * If no bits are set on the state struct after clearing things, the
424 * struct is freed and removed from the tree
425 */
426static int clear_state_bit(struct extent_map_tree *tree,
427 struct extent_state *state, int bits, int wake,
428 int delete)
429{
430 int ret = state->state & bits;
431 state->state &= ~bits;
432 if (wake)
433 wake_up(&state->wq);
434 if (delete || state->state == 0) {
435 if (state->in_tree) {
436 rb_erase(&state->rb_node, &tree->state);
437 state->in_tree = 0;
438 free_extent_state(state);
439 } else {
440 WARN_ON(1);
441 }
442 } else {
443 merge_state(tree, state);
444 }
445 return ret;
446}
447
448/*
449 * clear some bits on a range in the tree. This may require splitting
450 * or inserting elements in the tree, so the gfp mask is used to
451 * indicate which allocations or sleeping are allowed.
452 *
453 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
454 * the given range from the tree regardless of state (ie for truncate).
455 *
456 * the range [start, end] is inclusive.
457 *
458 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
459 * bits were already set, or zero if none of the bits were already set.
460 */
461int clear_extent_bit(struct extent_map_tree *tree, u64 start, u64 end,
462 int bits, int wake, int delete, gfp_t mask)
463{
464 struct extent_state *state;
465 struct extent_state *prealloc = NULL;
466 struct rb_node *node;
467 int err;
468 int set = 0;
469
470again:
471 if (!prealloc && (mask & __GFP_WAIT)) {
472 prealloc = alloc_extent_state(mask);
473 if (!prealloc)
474 return -ENOMEM;
475 }
476
477 write_lock_irq(&tree->lock);
478 /*
479 * this search will find the extents that end after
480 * our range starts
481 */
482 node = tree_search(&tree->state, start);
483 if (!node)
484 goto out;
485 state = rb_entry(node, struct extent_state, rb_node);
486 if (state->start > end)
487 goto out;
488 WARN_ON(state->end < start);
489
490 /*
491 * | ---- desired range ---- |
492 * | state | or
493 * | ------------- state -------------- |
494 *
495 * We need to split the extent we found, and may flip
496 * bits on second half.
497 *
498 * If the extent we found extends past our range, we
499 * just split and search again. It'll get split again
500 * the next time though.
501 *
502 * If the extent we found is inside our range, we clear
503 * the desired bit on it.
504 */
505
506 if (state->start < start) {
507 err = split_state(tree, state, prealloc, start);
508 BUG_ON(err == -EEXIST);
509 prealloc = NULL;
510 if (err)
511 goto out;
512 if (state->end <= end) {
513 start = state->end + 1;
514 set |= clear_state_bit(tree, state, bits,
515 wake, delete);
516 } else {
517 start = state->start;
518 }
519 goto search_again;
520 }
521 /*
522 * | ---- desired range ---- |
523 * | state |
524 * We need to split the extent, and clear the bit
525 * on the first half
526 */
527 if (state->start <= end && state->end > end) {
528 err = split_state(tree, state, prealloc, end + 1);
529 BUG_ON(err == -EEXIST);
530
531 if (wake)
532 wake_up(&state->wq);
533 set |= clear_state_bit(tree, prealloc, bits,
534 wake, delete);
535 prealloc = NULL;
536 goto out;
537 }
538
539 start = state->end + 1;
540 set |= clear_state_bit(tree, state, bits, wake, delete);
541 goto search_again;
542
543out:
544 write_unlock_irq(&tree->lock);
545 if (prealloc)
546 free_extent_state(prealloc);
547
548 return set;
549
550search_again:
551 if (start >= end)
552 goto out;
553 write_unlock_irq(&tree->lock);
554 if (mask & __GFP_WAIT)
555 cond_resched();
556 goto again;
557}
558EXPORT_SYMBOL(clear_extent_bit);
559
560static int wait_on_state(struct extent_map_tree *tree,
561 struct extent_state *state)
562{
563 DEFINE_WAIT(wait);
564 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
565 read_unlock_irq(&tree->lock);
566 schedule();
567 read_lock_irq(&tree->lock);
568 finish_wait(&state->wq, &wait);
569 return 0;
570}
571
572/*
573 * waits for one or more bits to clear on a range in the state tree.
574 * The range [start, end] is inclusive.
575 * The tree lock is taken by this function
576 */
577int wait_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits)
578{
579 struct extent_state *state;
580 struct rb_node *node;
581
582 read_lock_irq(&tree->lock);
583again:
584 while (1) {
585 /*
586 * this search will find all the extents that end after
587 * our range starts
588 */
589 node = tree_search(&tree->state, start);
590 if (!node)
591 break;
592
593 state = rb_entry(node, struct extent_state, rb_node);
594
595 if (state->start > end)
596 goto out;
597
598 if (state->state & bits) {
599 start = state->start;
600 atomic_inc(&state->refs);
601 wait_on_state(tree, state);
602 free_extent_state(state);
603 goto again;
604 }
605 start = state->end + 1;
606
607 if (start > end)
608 break;
609
610 if (need_resched()) {
611 read_unlock_irq(&tree->lock);
612 cond_resched();
613 read_lock_irq(&tree->lock);
614 }
615 }
616out:
617 read_unlock_irq(&tree->lock);
618 return 0;
619}
620EXPORT_SYMBOL(wait_extent_bit);
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 */
633int set_extent_bit(struct extent_map_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 int err = 0;
640 int set;
641 u64 last_start;
642 u64 last_end;
643again:
644 if (!prealloc && (mask & __GFP_WAIT)) {
645 prealloc = alloc_extent_state(mask);
646 if (!prealloc)
647 return -ENOMEM;
648 }
649
650 write_lock_irq(&tree->lock);
651 /*
652 * this search will find all the extents that end after
653 * our range starts.
654 */
655 node = tree_search(&tree->state, start);
656 if (!node) {
657 err = insert_state(tree, prealloc, start, end, bits);
658 prealloc = NULL;
659 BUG_ON(err == -EEXIST);
660 goto out;
661 }
662
663 state = rb_entry(node, struct extent_state, rb_node);
664 last_start = state->start;
665 last_end = state->end;
666
667 /*
668 * | ---- desired range ---- |
669 * | state |
670 *
671 * Just lock what we found and keep going
672 */
673 if (state->start == start && state->end <= end) {
674 set = state->state & bits;
675 if (set && exclusive) {
676 *failed_start = state->start;
677 err = -EEXIST;
678 goto out;
679 }
680 state->state |= bits;
681 start = state->end + 1;
682 merge_state(tree, state);
683 goto search_again;
684 }
685
686 /*
687 * | ---- desired range ---- |
688 * | state |
689 * or
690 * | ------------- state -------------- |
691 *
692 * We need to split the extent we found, and may flip bits on
693 * second half.
694 *
695 * If the extent we found extends past our
696 * range, we just split and search again. It'll get split
697 * again the next time though.
698 *
699 * If the extent we found is inside our range, we set the
700 * desired bit on it.
701 */
702 if (state->start < start) {
703 set = state->state & bits;
704 if (exclusive && set) {
705 *failed_start = start;
706 err = -EEXIST;
707 goto out;
708 }
709 err = split_state(tree, state, prealloc, start);
710 BUG_ON(err == -EEXIST);
711 prealloc = NULL;
712 if (err)
713 goto out;
714 if (state->end <= end) {
715 state->state |= bits;
716 start = state->end + 1;
717 merge_state(tree, state);
718 } else {
719 start = state->start;
720 }
721 goto search_again;
722 }
723 /*
724 * | ---- desired range ---- |
725 * | state |
726 * We need to split the extent, and set the bit
727 * on the first half
728 */
729 if (state->start <= end && state->end > end) {
730 set = state->state & bits;
731 if (exclusive && set) {
732 *failed_start = start;
733 err = -EEXIST;
734 goto out;
735 }
736 err = split_state(tree, state, prealloc, end + 1);
737 BUG_ON(err == -EEXIST);
738
739 prealloc->state |= bits;
740 merge_state(tree, prealloc);
741 prealloc = NULL;
742 goto out;
743 }
744
745 /*
746 * | ---- desired range ---- |
747 * | state | or | state |
748 *
749 * There's a hole, we need to insert something in it and
750 * ignore the extent we found.
751 */
752 if (state->start > start) {
753 u64 this_end;
754 if (end < last_start)
755 this_end = end;
756 else
757 this_end = last_start -1;
758 err = insert_state(tree, prealloc, start, this_end,
759 bits);
760 prealloc = NULL;
761 BUG_ON(err == -EEXIST);
762 if (err)
763 goto out;
764 start = this_end + 1;
765 goto search_again;
766 }
767 goto search_again;
768
769out:
770 write_unlock_irq(&tree->lock);
771 if (prealloc)
772 free_extent_state(prealloc);
773
774 return err;
775
776search_again:
777 if (start > end)
778 goto out;
779 write_unlock_irq(&tree->lock);
780 if (mask & __GFP_WAIT)
781 cond_resched();
782 goto again;
783}
784EXPORT_SYMBOL(set_extent_bit);
785
786/* wrappers around set/clear extent bit */
787int set_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
788 gfp_t mask)
789{
790 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
791 mask);
792}
793EXPORT_SYMBOL(set_extent_dirty);
794
795int clear_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
796 gfp_t mask)
797{
798 return clear_extent_bit(tree, start, end, EXTENT_DIRTY, 0, 0, mask);
799}
800EXPORT_SYMBOL(clear_extent_dirty);
801
802int set_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
803 gfp_t mask)
804{
805 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
806 mask);
807}
808EXPORT_SYMBOL(set_extent_new);
809
810int clear_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
811 gfp_t mask)
812{
813 return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask);
814}
815EXPORT_SYMBOL(clear_extent_new);
816
817int set_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
818 gfp_t mask)
819{
820 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
821 mask);
822}
823EXPORT_SYMBOL(set_extent_uptodate);
824
825int clear_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
826 gfp_t mask)
827{
828 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask);
829}
830EXPORT_SYMBOL(clear_extent_uptodate);
831
832int set_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end,
833 gfp_t mask)
834{
835 return set_extent_bit(tree, start, end, EXTENT_WRITEBACK,
836 0, NULL, mask);
837}
838EXPORT_SYMBOL(set_extent_writeback);
839
840int clear_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end,
841 gfp_t mask)
842{
843 return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask);
844}
845EXPORT_SYMBOL(clear_extent_writeback);
846
847int wait_on_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end)
848{
849 return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
850}
851EXPORT_SYMBOL(wait_on_extent_writeback);
852
853/*
854 * locks a range in ascending order, waiting for any locked regions
855 * it hits on the way. [start,end] are inclusive, and this will sleep.
856 */
857int lock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask)
858{
859 int err;
860 u64 failed_start;
861 while (1) {
862 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
863 &failed_start, mask);
864 if (err == -EEXIST && (mask & __GFP_WAIT)) {
865 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
866 start = failed_start;
867 } else {
868 break;
869 }
870 WARN_ON(start > end);
871 }
872 return err;
873}
874EXPORT_SYMBOL(lock_extent);
875
876int unlock_extent(struct extent_map_tree *tree, u64 start, u64 end,
877 gfp_t mask)
878{
879 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask);
880}
881EXPORT_SYMBOL(unlock_extent);
882
883/*
884 * helper function to set pages and extents in the tree dirty
885 */
886int set_range_dirty(struct extent_map_tree *tree, u64 start, u64 end)
887{
888 unsigned long index = start >> PAGE_CACHE_SHIFT;
889 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
890 struct page *page;
891
892 while (index <= end_index) {
893 page = find_get_page(tree->mapping, index);
894 BUG_ON(!page);
895 __set_page_dirty_nobuffers(page);
896 page_cache_release(page);
897 index++;
898 }
899 set_extent_dirty(tree, start, end, GFP_NOFS);
900 return 0;
901}
902EXPORT_SYMBOL(set_range_dirty);
903
904/*
905 * helper function to set both pages and extents in the tree writeback
906 */
907int set_range_writeback(struct extent_map_tree *tree, u64 start, u64 end)
908{
909 unsigned long index = start >> PAGE_CACHE_SHIFT;
910 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
911 struct page *page;
912
913 while (index <= end_index) {
914 page = find_get_page(tree->mapping, index);
915 BUG_ON(!page);
916 set_page_writeback(page);
917 page_cache_release(page);
918 index++;
919 }
920 set_extent_writeback(tree, start, end, GFP_NOFS);
921 return 0;
922}
923EXPORT_SYMBOL(set_range_writeback);
924
925/*
926 * helper function to lock both pages and extents in the tree.
927 * pages must be locked first.
928 */
929int lock_range(struct extent_map_tree *tree, u64 start, u64 end)
930{
931 unsigned long index = start >> PAGE_CACHE_SHIFT;
932 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
933 struct page *page;
934 int err;
935
936 while (index <= end_index) {
937 page = grab_cache_page(tree->mapping, index);
938 if (!page) {
939 err = -ENOMEM;
940 goto failed;
941 }
942 if (IS_ERR(page)) {
943 err = PTR_ERR(page);
944 goto failed;
945 }
946 index++;
947 }
948 lock_extent(tree, start, end, GFP_NOFS);
949 return 0;
950
951failed:
952 /*
953 * we failed above in getting the page at 'index', so we undo here
954 * up to but not including the page at 'index'
955 */
956 end_index = index;
957 index = start >> PAGE_CACHE_SHIFT;
958 while (index < end_index) {
959 page = find_get_page(tree->mapping, index);
960 unlock_page(page);
961 page_cache_release(page);
962 index++;
963 }
964 return err;
965}
966EXPORT_SYMBOL(lock_range);
967
968/*
969 * helper function to unlock both pages and extents in the tree.
970 */
971int unlock_range(struct extent_map_tree *tree, u64 start, u64 end)
972{
973 unsigned long index = start >> PAGE_CACHE_SHIFT;
974 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
975 struct page *page;
976
977 while (index <= end_index) {
978 page = find_get_page(tree->mapping, index);
979 unlock_page(page);
980 page_cache_release(page);
981 index++;
982 }
983 unlock_extent(tree, start, end, GFP_NOFS);
984 return 0;
985}
986EXPORT_SYMBOL(unlock_range);
987
988/*
989 * searches a range in the state tree for a given mask.
990 * If 'filled' == 1, this returns 1 only if ever extent in the tree
991 * has the bits set. Otherwise, 1 is returned if any bit in the
992 * range is found set.
993 */
994static int test_range_bit(struct extent_map_tree *tree, u64 start, u64 end,
995 int bits, int filled)
996{
997 struct extent_state *state = NULL;
998 struct rb_node *node;
999 int bitset = 0;
1000
1001 read_lock_irq(&tree->lock);
1002 node = tree_search(&tree->state, start);
1003 while (node && start <= end) {
1004 state = rb_entry(node, struct extent_state, rb_node);
1005 if (state->start > end)
1006 break;
1007
1008 if (filled && state->start > start) {
1009 bitset = 0;
1010 break;
1011 }
1012 if (state->state & bits) {
1013 bitset = 1;
1014 if (!filled)
1015 break;
1016 } else if (filled) {
1017 bitset = 0;
1018 break;
1019 }
1020 start = state->end + 1;
1021 if (start > end)
1022 break;
1023 node = rb_next(node);
1024 }
1025 read_unlock_irq(&tree->lock);
1026 return bitset;
1027}
1028
1029/*
1030 * helper function to set a given page up to date if all the
1031 * extents in the tree for that page are up to date
1032 */
1033static int check_page_uptodate(struct extent_map_tree *tree,
1034 struct page *page)
1035{
1036 u64 start = page->index << PAGE_CACHE_SHIFT;
1037 u64 end = start + PAGE_CACHE_SIZE - 1;
1038 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1))
1039 SetPageUptodate(page);
1040 return 0;
1041}
1042
1043/*
1044 * helper function to unlock a page if all the extents in the tree
1045 * for that page are unlocked
1046 */
1047static int check_page_locked(struct extent_map_tree *tree,
1048 struct page *page)
1049{
1050 u64 start = page->index << PAGE_CACHE_SHIFT;
1051 u64 end = start + PAGE_CACHE_SIZE - 1;
1052 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0))
1053 unlock_page(page);
1054 return 0;
1055}
1056
1057/*
1058 * helper function to end page writeback if all the extents
1059 * in the tree for that page are done with writeback
1060 */
1061static int check_page_writeback(struct extent_map_tree *tree,
1062 struct page *page)
1063{
1064 u64 start = page->index << PAGE_CACHE_SHIFT;
1065 u64 end = start + PAGE_CACHE_SIZE - 1;
1066 if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0))
1067 end_page_writeback(page);
1068 return 0;
1069}
1070
1071/* lots and lots of room for performance fixes in the end_bio funcs */
1072
1073/*
1074 * after a writepage IO is done, we need to:
1075 * clear the uptodate bits on error
1076 * clear the writeback bits in the extent tree for this IO
1077 * end_page_writeback if the page has no more pending IO
1078 *
1079 * Scheduling is not allowed, so the extent state tree is expected
1080 * to have one and only one object corresponding to this IO.
1081 */
1082static int end_bio_extent_writepage(struct bio *bio,
1083 unsigned int bytes_done, int err)
1084{
1085 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1086 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1087 struct extent_map_tree *tree = bio->bi_private;
1088 u64 start;
1089 u64 end;
1090 int whole_page;
1091
1092 if (bio->bi_size)
1093 return 1;
1094
1095 do {
1096 struct page *page = bvec->bv_page;
1097 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1098 end = start + bvec->bv_len - 1;
1099
1100 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1101 whole_page = 1;
1102 else
1103 whole_page = 0;
1104
1105 if (--bvec >= bio->bi_io_vec)
1106 prefetchw(&bvec->bv_page->flags);
1107
1108 if (!uptodate) {
1109 clear_extent_uptodate(tree, start, end, GFP_ATOMIC);
1110 ClearPageUptodate(page);
1111 SetPageError(page);
1112 }
1113 clear_extent_writeback(tree, start, end, GFP_ATOMIC);
1114
1115 if (whole_page)
1116 end_page_writeback(page);
1117 else
1118 check_page_writeback(tree, page);
1119 } while (bvec >= bio->bi_io_vec);
1120
1121 bio_put(bio);
1122 return 0;
1123}
1124
1125/*
1126 * after a readpage IO is done, we need to:
1127 * clear the uptodate bits on error
1128 * set the uptodate bits if things worked
1129 * set the page up to date if all extents in the tree are uptodate
1130 * clear the lock bit in the extent tree
1131 * unlock the page if there are no other extents locked for it
1132 *
1133 * Scheduling is not allowed, so the extent state tree is expected
1134 * to have one and only one object corresponding to this IO.
1135 */
1136static int end_bio_extent_readpage(struct bio *bio,
1137 unsigned int bytes_done, int err)
1138{
1139 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1140 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1141 struct extent_map_tree *tree = bio->bi_private;
1142 u64 start;
1143 u64 end;
1144 int whole_page;
1145
1146 if (bio->bi_size)
1147 return 1;
1148
1149 do {
1150 struct page *page = bvec->bv_page;
1151 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1152 end = start + bvec->bv_len - 1;
1153
1154 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1155 whole_page = 1;
1156 else
1157 whole_page = 0;
1158
1159 if (--bvec >= bio->bi_io_vec)
1160 prefetchw(&bvec->bv_page->flags);
1161
1162 if (uptodate) {
1163 set_extent_uptodate(tree, start, end, GFP_ATOMIC);
1164 if (whole_page)
1165 SetPageUptodate(page);
1166 else
1167 check_page_uptodate(tree, page);
1168 } else {
1169 ClearPageUptodate(page);
1170 SetPageError(page);
1171 }
1172
1173 unlock_extent(tree, start, end, GFP_ATOMIC);
1174
1175 if (whole_page)
1176 unlock_page(page);
1177 else
1178 check_page_locked(tree, page);
1179 } while (bvec >= bio->bi_io_vec);
1180
1181 bio_put(bio);
1182 return 0;
1183}
1184
1185/*
1186 * IO done from prepare_write is pretty simple, we just unlock
1187 * the structs in the extent tree when done, and set the uptodate bits
1188 * as appropriate.
1189 */
1190static int end_bio_extent_preparewrite(struct bio *bio,
1191 unsigned int bytes_done, int err)
1192{
1193 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1194 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1195 struct extent_map_tree *tree = bio->bi_private;
1196 u64 start;
1197 u64 end;
1198
1199 if (bio->bi_size)
1200 return 1;
1201
1202 do {
1203 struct page *page = bvec->bv_page;
1204 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1205 end = start + bvec->bv_len - 1;
1206
1207 if (--bvec >= bio->bi_io_vec)
1208 prefetchw(&bvec->bv_page->flags);
1209
1210 if (uptodate) {
1211 set_extent_uptodate(tree, start, end, GFP_ATOMIC);
1212 } else {
1213 ClearPageUptodate(page);
1214 SetPageError(page);
1215 }
1216
1217 unlock_extent(tree, start, end, GFP_ATOMIC);
1218
1219 } while (bvec >= bio->bi_io_vec);
1220
1221 bio_put(bio);
1222 return 0;
1223}
1224
1225static int submit_extent_page(int rw, struct extent_map_tree *tree,
1226 struct page *page, sector_t sector,
1227 size_t size, unsigned long offset,
1228 struct block_device *bdev,
1229 bio_end_io_t end_io_func)
1230{
1231 struct bio *bio;
1232 int ret = 0;
1233
1234 bio = bio_alloc(GFP_NOIO, 1);
1235
1236 bio->bi_sector = sector;
1237 bio->bi_bdev = bdev;
1238 bio->bi_io_vec[0].bv_page = page;
1239 bio->bi_io_vec[0].bv_len = size;
1240 bio->bi_io_vec[0].bv_offset = offset;
1241
1242 bio->bi_vcnt = 1;
1243 bio->bi_idx = 0;
1244 bio->bi_size = size;
1245
1246 bio->bi_end_io = end_io_func;
1247 bio->bi_private = tree;
1248
1249 bio_get(bio);
1250 submit_bio(rw, bio);
1251
1252 if (bio_flagged(bio, BIO_EOPNOTSUPP))
1253 ret = -EOPNOTSUPP;
1254
1255 bio_put(bio);
1256 return ret;
1257}
1258
1259/*
1260 * basic readpage implementation. Locked extent state structs are inserted
1261 * into the tree that are removed when the IO is done (by the end_io
1262 * handlers)
1263 */
1264int extent_read_full_page(struct extent_map_tree *tree, struct page *page,
1265 get_extent_t *get_extent)
1266{
1267 struct inode *inode = page->mapping->host;
1268 u64 start = page->index << PAGE_CACHE_SHIFT;
1269 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1270 u64 end;
1271 u64 cur = start;
1272 u64 extent_offset;
1273 u64 last_byte = i_size_read(inode);
1274 u64 block_start;
1275 u64 cur_end;
1276 sector_t sector;
1277 struct extent_map *em;
1278 struct block_device *bdev;
1279 int ret;
1280 int nr = 0;
1281 size_t page_offset = 0;
1282 size_t iosize;
1283 size_t blocksize = inode->i_sb->s_blocksize;
1284
1285 if (!PagePrivate(page)) {
1286 SetPagePrivate(page);
1287 set_page_private(page, 1);
1288 page_cache_get(page);
1289 }
1290
1291 end = page_end;
1292 lock_extent(tree, start, end, GFP_NOFS);
1293
1294 while (cur <= end) {
1295 if (cur >= last_byte) {
1296 iosize = PAGE_CACHE_SIZE - page_offset;
1297 zero_user_page(page, page_offset, iosize, KM_USER0);
1298 set_extent_uptodate(tree, cur, cur + iosize - 1,
1299 GFP_NOFS);
1300 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1301 break;
1302 }
1303 em = get_extent(inode, page, page_offset, cur, end, 0);
1304 if (IS_ERR(em) || !em) {
1305 SetPageError(page);
1306 unlock_extent(tree, cur, end, GFP_NOFS);
1307 break;
1308 }
1309
1310 extent_offset = cur - em->start;
1311 BUG_ON(em->end < cur);
1312 BUG_ON(end < cur);
1313
1314 iosize = min(em->end - cur, end - cur) + 1;
1315 cur_end = min(em->end, end);
1316 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
1317 sector = (em->block_start + extent_offset) >> 9;
1318 bdev = em->bdev;
1319 block_start = em->block_start;
1320 free_extent_map(em);
1321 em = NULL;
1322
1323 /* we've found a hole, just zero and go on */
1324 if (block_start == 0) {
1325 zero_user_page(page, page_offset, iosize, KM_USER0);
1326 set_extent_uptodate(tree, cur, cur + iosize - 1,
1327 GFP_NOFS);
1328 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1329 cur = cur + iosize;
1330 page_offset += iosize;
1331 continue;
1332 }
1333 /* the get_extent function already copied into the page */
1334 if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) {
1335 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1336 cur = cur + iosize;
1337 page_offset += iosize;
1338 continue;
1339 }
1340
1341 ret = submit_extent_page(READ, tree, page,
1342 sector, iosize, page_offset, bdev,
1343 end_bio_extent_readpage);
1344 if (ret)
1345 SetPageError(page);
1346 cur = cur + iosize;
1347 page_offset += iosize;
1348 nr++;
1349 }
1350 if (!nr) {
1351 if (!PageError(page))
1352 SetPageUptodate(page);
1353 unlock_page(page);
1354 }
1355 return 0;
1356}
1357EXPORT_SYMBOL(extent_read_full_page);
1358
1359/*
1360 * the writepage semantics are similar to regular writepage. extent
1361 * records are inserted to lock ranges in the tree, and as dirty areas
1362 * are found, they are marked writeback. Then the lock bits are removed
1363 * and the end_io handler clears the writeback ranges
1364 */
1365int extent_write_full_page(struct extent_map_tree *tree, struct page *page,
1366 get_extent_t *get_extent,
1367 struct writeback_control *wbc)
1368{
1369 struct inode *inode = page->mapping->host;
1370 u64 start = page->index << PAGE_CACHE_SHIFT;
1371 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1372 u64 end;
1373 u64 cur = start;
1374 u64 extent_offset;
1375 u64 last_byte = i_size_read(inode);
1376 u64 block_start;
1377 sector_t sector;
1378 struct extent_map *em;
1379 struct block_device *bdev;
1380 int ret;
1381 int nr = 0;
1382 size_t page_offset = 0;
1383 size_t iosize;
1384 size_t blocksize;
1385 loff_t i_size = i_size_read(inode);
1386 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
1387
1388 if (page->index > end_index) {
1389 clear_extent_dirty(tree, start, page_end, GFP_NOFS);
1390 unlock_page(page);
1391 return 0;
1392 }
1393
1394 if (page->index == end_index) {
1395 size_t offset = i_size & (PAGE_CACHE_SIZE - 1);
1396 zero_user_page(page, offset,
1397 PAGE_CACHE_SIZE - offset, KM_USER0);
1398 }
1399
1400 if (!PagePrivate(page)) {
1401 SetPagePrivate(page);
1402 set_page_private(page, 1);
1403 page_cache_get(page);
1404 }
1405
1406 end = page_end;
1407 lock_extent(tree, start, page_end, GFP_NOFS);
1408
1409 if (last_byte <= start) {
1410 clear_extent_dirty(tree, start, page_end, GFP_NOFS);
1411 goto done;
1412 }
1413
1414 set_extent_uptodate(tree, start, page_end, GFP_NOFS);
1415 blocksize = inode->i_sb->s_blocksize;
1416
1417 while (cur <= end) {
1418 if (cur >= last_byte) {
1419 clear_extent_dirty(tree, cur, page_end, GFP_NOFS);
1420 break;
1421 }
1422 em = get_extent(inode, page, page_offset, cur, end, 1);
1423 if (IS_ERR(em) || !em) {
1424 SetPageError(page);
1425 break;
1426 }
1427
1428 extent_offset = cur - em->start;
1429 BUG_ON(em->end < cur);
1430 BUG_ON(end < cur);
1431 iosize = min(em->end - cur, end - cur) + 1;
1432 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
1433 sector = (em->block_start + extent_offset) >> 9;
1434 bdev = em->bdev;
1435 block_start = em->block_start;
1436 free_extent_map(em);
1437 em = NULL;
1438
1439 if (block_start == 0 || block_start == EXTENT_MAP_INLINE) {
1440 clear_extent_dirty(tree, cur,
1441 cur + iosize - 1, GFP_NOFS);
1442 cur = cur + iosize;
1443 page_offset += iosize;
1444 continue;
1445 }
1446
1447 /* leave this out until we have a page_mkwrite call */
1448 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
1449 EXTENT_DIRTY, 0)) {
1450 cur = cur + iosize;
1451 page_offset += iosize;
1452 continue;
1453 }
1454 clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS);
1455 set_range_writeback(tree, cur, cur + iosize - 1);
1456 ret = submit_extent_page(WRITE, tree, page,
1457 sector, iosize, page_offset, bdev,
1458 end_bio_extent_writepage);
1459 if (ret)
1460 SetPageError(page);
1461 cur = cur + iosize;
1462 page_offset += iosize;
1463 nr++;
1464 }
1465done:
1466 WARN_ON(test_range_bit(tree, start, page_end, EXTENT_DIRTY, 0));
1467 unlock_extent(tree, start, page_end, GFP_NOFS);
1468 unlock_page(page);
1469 return 0;
1470}
1471EXPORT_SYMBOL(extent_write_full_page);
1472
1473/*
1474 * basic invalidatepage code, this waits on any locked or writeback
1475 * ranges corresponding to the page, and then deletes any extent state
1476 * records from the tree
1477 */
1478int extent_invalidatepage(struct extent_map_tree *tree,
1479 struct page *page, unsigned long offset)
1480{
1481 u64 start = (page->index << PAGE_CACHE_SHIFT);
1482 u64 end = start + PAGE_CACHE_SIZE - 1;
1483 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
1484
1485 start += (offset + blocksize -1) & ~(blocksize - 1);
1486 if (start > end)
1487 return 0;
1488
1489 lock_extent(tree, start, end, GFP_NOFS);
1490 wait_on_extent_writeback(tree, start, end);
1491 clear_extent_bit(tree, start, end, EXTENT_LOCKED | EXTENT_DIRTY,
1492 1, 1, GFP_NOFS);
1493 return 0;
1494}
1495EXPORT_SYMBOL(extent_invalidatepage);
1496
1497/*
1498 * simple commit_write call, set_range_dirty is used to mark both
1499 * the pages and the extent records as dirty
1500 */
1501int extent_commit_write(struct extent_map_tree *tree,
1502 struct inode *inode, struct page *page,
1503 unsigned from, unsigned to)
1504{
1505 loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
1506
1507 if (!PagePrivate(page)) {
1508 SetPagePrivate(page);
1509 set_page_private(page, 1);
1510 page_cache_get(page);
1511 }
1512
1513 set_page_dirty(page);
1514
1515 if (pos > inode->i_size) {
1516 i_size_write(inode, pos);
1517 mark_inode_dirty(inode);
1518 }
1519 return 0;
1520}
1521EXPORT_SYMBOL(extent_commit_write);
1522
1523int extent_prepare_write(struct extent_map_tree *tree,
1524 struct inode *inode, struct page *page,
1525 unsigned from, unsigned to, get_extent_t *get_extent)
1526{
1527 u64 page_start = page->index << PAGE_CACHE_SHIFT;
1528 u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
1529 u64 block_start;
1530 u64 orig_block_start;
1531 u64 block_end;
1532 u64 cur_end;
1533 struct extent_map *em;
1534 unsigned blocksize = 1 << inode->i_blkbits;
1535 size_t page_offset = 0;
1536 size_t block_off_start;
1537 size_t block_off_end;
1538 int err = 0;
1539 int iocount = 0;
1540 int ret = 0;
1541 int isnew;
1542
1543 if (!PagePrivate(page)) {
1544 SetPagePrivate(page);
1545 set_page_private(page, 1);
1546 page_cache_get(page);
1547 }
1548 block_start = (page_start + from) & ~((u64)blocksize - 1);
1549 block_end = (page_start + to - 1) | (blocksize - 1);
1550 orig_block_start = block_start;
1551
1552 lock_extent(tree, page_start, page_end, GFP_NOFS);
1553 while(block_start <= block_end) {
1554 em = get_extent(inode, page, page_offset, block_start,
1555 block_end, 1);
1556 if (IS_ERR(em) || !em) {
1557 goto err;
1558 }
1559 cur_end = min(block_end, em->end);
1560 block_off_start = block_start & (PAGE_CACHE_SIZE - 1);
1561 block_off_end = block_off_start + blocksize;
1562 isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS);
1563
1564 if (!PageUptodate(page) && isnew &&
1565 (block_off_end > to || block_off_start < from)) {
1566 void *kaddr;
1567
1568 kaddr = kmap_atomic(page, KM_USER0);
1569 if (block_off_end > to)
1570 memset(kaddr + to, 0, block_off_end - to);
1571 if (block_off_start < from)
1572 memset(kaddr + block_off_start, 0,
1573 from - block_off_start);
1574 flush_dcache_page(page);
1575 kunmap_atomic(kaddr, KM_USER0);
1576 }
1577 if (!isnew && !PageUptodate(page) &&
1578 (block_off_end > to || block_off_start < from) &&
1579 !test_range_bit(tree, block_start, cur_end,
1580 EXTENT_UPTODATE, 1)) {
1581 u64 sector;
1582 u64 extent_offset = block_start - em->start;
1583 size_t iosize;
1584 sector = (em->block_start + extent_offset) >> 9;
1585 iosize = (cur_end - block_start + blocksize - 1) &
1586 ~((u64)blocksize - 1);
1587 /*
1588 * we've already got the extent locked, but we
1589 * need to split the state such that our end_bio
1590 * handler can clear the lock.
1591 */
1592 set_extent_bit(tree, block_start,
1593 block_start + iosize - 1,
1594 EXTENT_LOCKED, 0, NULL, GFP_NOFS);
1595 ret = submit_extent_page(READ, tree, page,
1596 sector, iosize, page_offset, em->bdev,
1597 end_bio_extent_preparewrite);
1598 iocount++;
1599 block_start = block_start + iosize;
1600 } else {
1601 set_extent_uptodate(tree, block_start, cur_end,
1602 GFP_NOFS);
1603 unlock_extent(tree, block_start, cur_end, GFP_NOFS);
1604 block_start = cur_end + 1;
1605 }
1606 page_offset = block_start & (PAGE_CACHE_SIZE - 1);
1607 free_extent_map(em);
1608 }
1609 if (iocount) {
1610 wait_extent_bit(tree, orig_block_start,
1611 block_end, EXTENT_LOCKED);
1612 }
1613 check_page_uptodate(tree, page);
1614err:
1615 /* FIXME, zero out newly allocated blocks on error */
1616 return err;
1617}
1618EXPORT_SYMBOL(extent_prepare_write);
1619
1620/*
1621 * a helper for releasepage. As long as there are no locked extents
1622 * in the range corresponding to the page, both state records and extent
1623 * map records are removed
1624 */
1625int try_release_extent_mapping(struct extent_map_tree *tree, struct page *page)
1626{
1627 struct extent_map *em;
1628 u64 start = page->index << PAGE_CACHE_SHIFT;
1629 u64 end = start + PAGE_CACHE_SIZE - 1;
1630 u64 orig_start = start;
1631
1632 while (start <= end) {
1633 em = lookup_extent_mapping(tree, start, end);
1634 if (!em || IS_ERR(em))
1635 break;
1636 if (test_range_bit(tree, em->start, em->end,
1637 EXTENT_LOCKED, 0)) {
1638 free_extent_map(em);
1639 start = em->end + 1;
1640printk("range still locked %Lu %Lu\n", em->start, em->end);
1641 break;
1642 }
1643 remove_extent_mapping(tree, em);
1644 start = em->end + 1;
1645 /* once for the rb tree */
1646 free_extent_map(em);
1647 /* once for us */
1648 free_extent_map(em);
1649 }
1650 WARN_ON(test_range_bit(tree, orig_start, end, EXTENT_WRITEBACK, 0));
1651 clear_extent_bit(tree, orig_start, end, EXTENT_UPTODATE,
1652 1, 1, GFP_NOFS);
1653 return 1;
1654}
1655EXPORT_SYMBOL(try_release_extent_mapping);
1656