1 #include <linux/bitops.h>
2 #include <linux/slab.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"
13 static struct kmem_cache *extent_map_cache;
14 static struct kmem_cache *extent_state_cache;
20 struct rb_node rb_node;
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)
31 #define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
33 void __init extent_map_init(void)
35 extent_map_cache = kmem_cache_create("extent_map",
36 sizeof(struct extent_map), 0,
37 SLAB_RECLAIM_ACCOUNT |
40 extent_state_cache = kmem_cache_create("extent_state",
41 sizeof(struct extent_state), 0,
42 SLAB_RECLAIM_ACCOUNT |
47 void __exit extent_map_exit(void)
50 kmem_cache_destroy(extent_map_cache);
51 if (extent_state_cache)
52 kmem_cache_destroy(extent_state_cache);
55 void extent_map_tree_init(struct extent_map_tree *tree,
56 struct address_space *mapping, gfp_t mask)
58 tree->map.rb_node = NULL;
59 tree->state.rb_node = NULL;
61 rwlock_init(&tree->lock);
62 tree->mapping = mapping;
64 EXPORT_SYMBOL(extent_map_tree_init);
66 struct extent_map *alloc_extent_map(gfp_t mask)
68 struct extent_map *em;
69 em = kmem_cache_alloc(extent_map_cache, mask);
70 if (!em || IS_ERR(em))
73 atomic_set(&em->refs, 1);
76 EXPORT_SYMBOL(alloc_extent_map);
78 void free_extent_map(struct extent_map *em)
82 if (atomic_dec_and_test(&em->refs)) {
84 kmem_cache_free(extent_map_cache, em);
87 EXPORT_SYMBOL(free_extent_map);
90 struct extent_state *alloc_extent_state(gfp_t mask)
92 struct extent_state *state;
93 state = kmem_cache_alloc(extent_state_cache, mask);
94 if (!state || IS_ERR(state))
99 atomic_set(&state->refs, 1);
100 init_waitqueue_head(&state->wq);
103 EXPORT_SYMBOL(alloc_extent_state);
105 void free_extent_state(struct extent_state *state)
109 if (atomic_dec_and_test(&state->refs)) {
110 WARN_ON(state->in_tree);
111 kmem_cache_free(extent_state_cache, state);
114 EXPORT_SYMBOL(free_extent_state);
116 static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
117 struct rb_node *node)
119 struct rb_node ** p = &root->rb_node;
120 struct rb_node * parent = NULL;
121 struct tree_entry *entry;
125 entry = rb_entry(parent, struct tree_entry, rb_node);
127 if (offset < entry->start)
129 else if (offset > entry->end)
135 entry = rb_entry(node, struct tree_entry, rb_node);
137 rb_link_node(node, parent, p);
138 rb_insert_color(node, root);
142 static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
143 struct rb_node **prev_ret)
145 struct rb_node * n = root->rb_node;
146 struct rb_node *prev = NULL;
147 struct tree_entry *entry;
148 struct tree_entry *prev_entry = NULL;
151 entry = rb_entry(n, struct tree_entry, rb_node);
155 if (offset < entry->start)
157 else if (offset > entry->end)
164 while(prev && offset > prev_entry->end) {
165 prev = rb_next(prev);
166 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
172 static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
174 struct rb_node *prev;
176 ret = __tree_search(root, offset, &prev);
182 static int tree_delete(struct rb_root *root, u64 offset)
184 struct rb_node *node;
185 struct tree_entry *entry;
187 node = __tree_search(root, offset, NULL);
190 entry = rb_entry(node, struct tree_entry, rb_node);
192 rb_erase(node, root);
197 * add_extent_mapping tries a simple backward merge with existing
198 * mappings. The extent_map struct passed in will be inserted into
199 * the tree directly (no copies made, just a reference taken).
201 int add_extent_mapping(struct extent_map_tree *tree,
202 struct extent_map *em)
205 struct extent_map *prev = NULL;
208 write_lock_irq(&tree->lock);
209 rb = tree_insert(&tree->map, em->end, &em->rb_node);
211 prev = rb_entry(rb, struct extent_map, rb_node);
212 printk("found extent map %Lu %Lu on insert of %Lu %Lu\n", prev->start, prev->end, em->start, em->end);
216 atomic_inc(&em->refs);
217 if (em->start != 0) {
218 rb = rb_prev(&em->rb_node);
220 prev = rb_entry(rb, struct extent_map, rb_node);
221 if (prev && prev->end + 1 == em->start &&
222 ((em->block_start == 0 && prev->block_start == 0) ||
223 (em->block_start == prev->block_end + 1))) {
224 em->start = prev->start;
225 em->block_start = prev->block_start;
226 rb_erase(&prev->rb_node, &tree->map);
228 free_extent_map(prev);
232 write_unlock_irq(&tree->lock);
235 EXPORT_SYMBOL(add_extent_mapping);
238 * lookup_extent_mapping returns the first extent_map struct in the
239 * tree that intersects the [start, end] (inclusive) range. There may
240 * be additional objects in the tree that intersect, so check the object
241 * returned carefully to make sure you don't need additional lookups.
243 struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
246 struct extent_map *em;
247 struct rb_node *rb_node;
249 read_lock_irq(&tree->lock);
250 rb_node = tree_search(&tree->map, start);
255 if (IS_ERR(rb_node)) {
256 em = ERR_PTR(PTR_ERR(rb_node));
259 em = rb_entry(rb_node, struct extent_map, rb_node);
260 if (em->end < start || em->start > end) {
264 atomic_inc(&em->refs);
266 read_unlock_irq(&tree->lock);
269 EXPORT_SYMBOL(lookup_extent_mapping);
272 * removes an extent_map struct from the tree. No reference counts are
273 * dropped, and no checks are done to see if the range is in use
275 int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
279 write_lock_irq(&tree->lock);
280 ret = tree_delete(&tree->map, em->end);
281 write_unlock_irq(&tree->lock);
284 EXPORT_SYMBOL(remove_extent_mapping);
287 * utility function to look for merge candidates inside a given range.
288 * Any extents with matching state are merged together into a single
289 * extent in the tree. Extents with EXTENT_IO in their state field
290 * are not merged because the end_io handlers need to be able to do
291 * operations on them without sleeping (or doing allocations/splits).
293 * This should be called with the tree lock held.
295 static int merge_state(struct extent_map_tree *tree,
296 struct extent_state *state)
298 struct extent_state *other;
299 struct rb_node *other_node;
301 if (state->state & EXTENT_IOBITS)
304 other_node = rb_prev(&state->rb_node);
306 other = rb_entry(other_node, struct extent_state, rb_node);
307 if (other->end == state->start - 1 &&
308 other->state == state->state) {
309 state->start = other->start;
311 rb_erase(&other->rb_node, &tree->state);
312 free_extent_state(other);
315 other_node = rb_next(&state->rb_node);
317 other = rb_entry(other_node, struct extent_state, rb_node);
318 if (other->start == state->end + 1 &&
319 other->state == state->state) {
320 other->start = state->start;
322 rb_erase(&state->rb_node, &tree->state);
323 free_extent_state(state);
330 * insert an extent_state struct into the tree. 'bits' are set on the
331 * struct before it is inserted.
333 * This may return -EEXIST if the extent is already there, in which case the
334 * state struct is freed.
336 * The tree lock is not taken internally. This is a utility function and
337 * probably isn't what you want to call (see set/clear_extent_bit).
339 static int insert_state(struct extent_map_tree *tree,
340 struct extent_state *state, u64 start, u64 end,
343 struct rb_node *node;
346 printk("end < start %Lu %Lu\n", end, start);
349 state->state |= bits;
350 state->start = start;
352 if ((end & 4095) == 0) {
353 printk("insert state %Lu %Lu strange end\n", start, end);
356 node = tree_insert(&tree->state, end, &state->rb_node);
358 struct extent_state *found;
359 found = rb_entry(node, struct extent_state, rb_node);
360 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, start, end);
361 free_extent_state(state);
364 merge_state(tree, state);
369 * split a given extent state struct in two, inserting the preallocated
370 * struct 'prealloc' as the newly created second half. 'split' indicates an
371 * offset inside 'orig' where it should be split.
374 * the tree has 'orig' at [orig->start, orig->end]. After calling, there
375 * are two extent state structs in the tree:
376 * prealloc: [orig->start, split - 1]
377 * orig: [ split, orig->end ]
379 * The tree locks are not taken by this function. They need to be held
382 static int split_state(struct extent_map_tree *tree, struct extent_state *orig,
383 struct extent_state *prealloc, u64 split)
385 struct rb_node *node;
386 prealloc->start = orig->start;
387 prealloc->end = split - 1;
388 prealloc->state = orig->state;
390 if ((prealloc->end & 4095) == 0) {
391 printk("insert state %Lu %Lu strange end\n", prealloc->start,
395 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
397 struct extent_state *found;
398 found = rb_entry(node, struct extent_state, rb_node);
399 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, prealloc->start, prealloc->end);
400 free_extent_state(prealloc);
407 * utility function to clear some bits in an extent state struct.
408 * it will optionally wake up any one waiting on this state (wake == 1), or
409 * forcibly remove the state from the tree (delete == 1).
411 * If no bits are set on the state struct after clearing things, the
412 * struct is freed and removed from the tree
414 static int clear_state_bit(struct extent_map_tree *tree,
415 struct extent_state *state, int bits, int wake,
418 int ret = state->state & bits;
419 state->state &= ~bits;
422 if (delete || state->state == 0) {
423 if (state->in_tree) {
424 rb_erase(&state->rb_node, &tree->state);
426 free_extent_state(state);
431 merge_state(tree, state);
437 * clear some bits on a range in the tree. This may require splitting
438 * or inserting elements in the tree, so the gfp mask is used to
439 * indicate which allocations or sleeping are allowed.
441 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
442 * the given range from the tree regardless of state (ie for truncate).
444 * the range [start, end] is inclusive.
446 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
447 * bits were already set, or zero if none of the bits were already set.
449 int clear_extent_bit(struct extent_map_tree *tree, u64 start, u64 end,
450 int bits, int wake, int delete, gfp_t mask)
452 struct extent_state *state;
453 struct extent_state *prealloc = NULL;
454 struct rb_node *node;
459 if (!prealloc && (mask & __GFP_WAIT)) {
460 prealloc = alloc_extent_state(mask);
465 write_lock_irq(&tree->lock);
467 * this search will find the extents that end after
470 node = tree_search(&tree->state, start);
473 state = rb_entry(node, struct extent_state, rb_node);
474 if (state->start > end)
476 WARN_ON(state->end < start);
479 * | ---- desired range ---- |
481 * | ------------- state -------------- |
483 * We need to split the extent we found, and may flip
484 * bits on second half.
486 * If the extent we found extends past our range, we
487 * just split and search again. It'll get split again
488 * the next time though.
490 * If the extent we found is inside our range, we clear
491 * the desired bit on it.
494 if (state->start < start) {
495 err = split_state(tree, state, prealloc, start);
496 BUG_ON(err == -EEXIST);
500 if (state->end <= end) {
501 start = state->end + 1;
502 set |= clear_state_bit(tree, state, bits,
505 start = state->start;
510 * | ---- desired range ---- |
512 * We need to split the extent, and clear the bit
515 if (state->start <= end && state->end > end) {
516 err = split_state(tree, state, prealloc, end + 1);
517 BUG_ON(err == -EEXIST);
521 set |= clear_state_bit(tree, prealloc, bits,
527 start = state->end + 1;
528 set |= clear_state_bit(tree, state, bits, wake, delete);
532 write_unlock_irq(&tree->lock);
534 free_extent_state(prealloc);
541 write_unlock_irq(&tree->lock);
542 if (mask & __GFP_WAIT)
546 EXPORT_SYMBOL(clear_extent_bit);
548 static int wait_on_state(struct extent_map_tree *tree,
549 struct extent_state *state)
552 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
553 read_unlock_irq(&tree->lock);
555 read_lock_irq(&tree->lock);
556 finish_wait(&state->wq, &wait);
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
565 int wait_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits)
567 struct extent_state *state;
568 struct rb_node *node;
570 read_lock_irq(&tree->lock);
574 * this search will find all the extents that end after
577 node = tree_search(&tree->state, start);
581 state = rb_entry(node, struct extent_state, rb_node);
583 if (state->start > end)
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);
593 start = state->end + 1;
598 if (need_resched()) {
599 read_unlock_irq(&tree->lock);
601 read_lock_irq(&tree->lock);
605 read_unlock_irq(&tree->lock);
608 EXPORT_SYMBOL(wait_extent_bit);
611 * set some bits on a range in the tree. This may require allocations
612 * or sleeping, so the gfp mask is used to indicate what is allowed.
614 * If 'exclusive' == 1, this will fail with -EEXIST if some part of the
615 * range already has the desired bits set. The start of the existing
616 * range is returned in failed_start in this case.
618 * [start, end] is inclusive
619 * This takes the tree lock.
621 int set_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits,
622 int exclusive, u64 *failed_start, gfp_t mask)
624 struct extent_state *state;
625 struct extent_state *prealloc = NULL;
626 struct rb_node *node;
632 if (!prealloc && (mask & __GFP_WAIT)) {
633 prealloc = alloc_extent_state(mask);
638 write_lock_irq(&tree->lock);
640 * this search will find all the extents that end after
643 node = tree_search(&tree->state, start);
645 err = insert_state(tree, prealloc, start, end, bits);
647 BUG_ON(err == -EEXIST);
651 state = rb_entry(node, struct extent_state, rb_node);
652 last_start = state->start;
653 last_end = state->end;
656 * | ---- desired range ---- |
659 * Just lock what we found and keep going
661 if (state->start == start && state->end <= end) {
662 set = state->state & bits;
663 if (set && exclusive) {
664 *failed_start = state->start;
668 state->state |= bits;
669 start = state->end + 1;
670 merge_state(tree, state);
675 * | ---- desired range ---- |
678 * | ------------- state -------------- |
680 * We need to split the extent we found, and may flip bits on
683 * If the extent we found extends past our
684 * range, we just split and search again. It'll get split
685 * again the next time though.
687 * If the extent we found is inside our range, we set the
690 if (state->start < start) {
691 set = state->state & bits;
692 if (exclusive && set) {
693 *failed_start = start;
697 err = split_state(tree, state, prealloc, start);
698 BUG_ON(err == -EEXIST);
702 if (state->end <= end) {
703 state->state |= bits;
704 start = state->end + 1;
705 merge_state(tree, state);
707 start = state->start;
712 * | ---- desired range ---- |
714 * We need to split the extent, and set the bit
717 if (state->start <= end && state->end > end) {
718 set = state->state & bits;
719 if (exclusive && set) {
720 *failed_start = start;
724 err = split_state(tree, state, prealloc, end + 1);
725 BUG_ON(err == -EEXIST);
727 prealloc->state |= bits;
728 merge_state(tree, prealloc);
734 * | ---- desired range ---- |
735 * | state | or | state |
737 * There's a hole, we need to insert something in it and
738 * ignore the extent we found.
740 if (state->start > start) {
742 if (end < last_start)
745 this_end = last_start -1;
746 err = insert_state(tree, prealloc, start, this_end,
749 BUG_ON(err == -EEXIST);
752 start = this_end + 1;
758 write_unlock_irq(&tree->lock);
760 free_extent_state(prealloc);
767 write_unlock_irq(&tree->lock);
768 if (mask & __GFP_WAIT)
772 EXPORT_SYMBOL(set_extent_bit);
774 /* wrappers around set/clear extent bit */
775 int set_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
778 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
781 EXPORT_SYMBOL(set_extent_dirty);
783 int set_extent_delalloc(struct extent_map_tree *tree, u64 start, u64 end,
786 return set_extent_bit(tree, start, end,
787 EXTENT_DELALLOC | EXTENT_DIRTY, 0, NULL,
790 EXPORT_SYMBOL(set_extent_delalloc);
792 int clear_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
795 return clear_extent_bit(tree, start, end,
796 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, mask);
798 EXPORT_SYMBOL(clear_extent_dirty);
800 int set_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
803 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
806 EXPORT_SYMBOL(set_extent_new);
808 int clear_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
811 return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask);
813 EXPORT_SYMBOL(clear_extent_new);
815 int set_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
818 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
821 EXPORT_SYMBOL(set_extent_uptodate);
823 int clear_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
826 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask);
828 EXPORT_SYMBOL(clear_extent_uptodate);
830 int set_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end,
833 return set_extent_bit(tree, start, end, EXTENT_WRITEBACK,
836 EXPORT_SYMBOL(set_extent_writeback);
838 int clear_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end,
841 return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask);
843 EXPORT_SYMBOL(clear_extent_writeback);
845 int wait_on_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end)
847 return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
849 EXPORT_SYMBOL(wait_on_extent_writeback);
852 * locks a range in ascending order, waiting for any locked regions
853 * it hits on the way. [start,end] are inclusive, and this will sleep.
855 int lock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask)
860 err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
861 &failed_start, mask);
862 if (err == -EEXIST && (mask & __GFP_WAIT)) {
863 wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
864 start = failed_start;
868 WARN_ON(start > end);
872 EXPORT_SYMBOL(lock_extent);
874 int unlock_extent(struct extent_map_tree *tree, u64 start, u64 end,
877 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask);
879 EXPORT_SYMBOL(unlock_extent);
882 * helper function to set pages and extents in the tree dirty
884 int set_range_dirty(struct extent_map_tree *tree, u64 start, u64 end)
886 unsigned long index = start >> PAGE_CACHE_SHIFT;
887 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
890 while (index <= end_index) {
891 page = find_get_page(tree->mapping, index);
893 __set_page_dirty_nobuffers(page);
894 page_cache_release(page);
897 set_extent_dirty(tree, start, end, GFP_NOFS);
900 EXPORT_SYMBOL(set_range_dirty);
903 * helper function to set both pages and extents in the tree writeback
905 int set_range_writeback(struct extent_map_tree *tree, u64 start, u64 end)
907 unsigned long index = start >> PAGE_CACHE_SHIFT;
908 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
911 while (index <= end_index) {
912 page = find_get_page(tree->mapping, index);
914 set_page_writeback(page);
915 page_cache_release(page);
918 set_extent_writeback(tree, start, end, GFP_NOFS);
921 EXPORT_SYMBOL(set_range_writeback);
923 u64 find_lock_delalloc_range(struct extent_map_tree *tree,
924 u64 start, u64 lock_start, u64 *end, u64 max_bytes)
926 struct rb_node *node;
927 struct extent_state *state;
928 u64 cur_start = start;
932 write_lock_irq(&tree->lock);
934 * this search will find all the extents that end after
938 node = tree_search(&tree->state, cur_start);
939 if (!node || IS_ERR(node)) {
944 state = rb_entry(node, struct extent_state, rb_node);
945 if (state->start != cur_start) {
948 if (!(state->state & EXTENT_DELALLOC)) {
951 if (state->start >= lock_start) {
952 if (state->state & EXTENT_LOCKED) {
954 atomic_inc(&state->refs);
955 write_unlock_irq(&tree->lock);
957 write_lock_irq(&tree->lock);
958 finish_wait(&state->wq, &wait);
959 free_extent_state(state);
962 state->state |= EXTENT_LOCKED;
966 cur_start = state->end + 1;
967 node = rb_next(node);
970 total_bytes = state->end - state->start + 1;
971 if (total_bytes >= max_bytes)
975 write_unlock_irq(&tree->lock);
980 * helper function to lock both pages and extents in the tree.
981 * pages must be locked first.
983 int lock_range(struct extent_map_tree *tree, u64 start, u64 end)
985 unsigned long index = start >> PAGE_CACHE_SHIFT;
986 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
990 while (index <= end_index) {
991 page = grab_cache_page(tree->mapping, index);
1002 lock_extent(tree, start, end, GFP_NOFS);
1007 * we failed above in getting the page at 'index', so we undo here
1008 * up to but not including the page at 'index'
1011 index = start >> PAGE_CACHE_SHIFT;
1012 while (index < end_index) {
1013 page = find_get_page(tree->mapping, index);
1015 page_cache_release(page);
1020 EXPORT_SYMBOL(lock_range);
1023 * helper function to unlock both pages and extents in the tree.
1025 int unlock_range(struct extent_map_tree *tree, u64 start, u64 end)
1027 unsigned long index = start >> PAGE_CACHE_SHIFT;
1028 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
1031 while (index <= end_index) {
1032 page = find_get_page(tree->mapping, index);
1034 page_cache_release(page);
1037 unlock_extent(tree, start, end, GFP_NOFS);
1040 EXPORT_SYMBOL(unlock_range);
1042 int set_state_private(struct extent_map_tree *tree, u64 start, u64 private)
1044 struct rb_node *node;
1045 struct extent_state *state;
1048 write_lock_irq(&tree->lock);
1050 * this search will find all the extents that end after
1053 node = tree_search(&tree->state, start);
1054 if (!node || IS_ERR(node)) {
1058 state = rb_entry(node, struct extent_state, rb_node);
1059 if (state->start != start) {
1063 state->private = private;
1065 write_unlock_irq(&tree->lock);
1070 int get_state_private(struct extent_map_tree *tree, u64 start, u64 *private)
1072 struct rb_node *node;
1073 struct extent_state *state;
1076 read_lock_irq(&tree->lock);
1078 * this search will find all the extents that end after
1081 node = tree_search(&tree->state, start);
1082 if (!node || IS_ERR(node)) {
1086 state = rb_entry(node, struct extent_state, rb_node);
1087 if (state->start != start) {
1091 *private = state->private;
1093 read_unlock_irq(&tree->lock);
1098 * searches a range in the state tree for a given mask.
1099 * If 'filled' == 1, this returns 1 only if ever extent in the tree
1100 * has the bits set. Otherwise, 1 is returned if any bit in the
1101 * range is found set.
1103 static int test_range_bit(struct extent_map_tree *tree, u64 start, u64 end,
1104 int bits, int filled)
1106 struct extent_state *state = NULL;
1107 struct rb_node *node;
1110 read_lock_irq(&tree->lock);
1111 node = tree_search(&tree->state, start);
1112 while (node && start <= end) {
1113 state = rb_entry(node, struct extent_state, rb_node);
1114 if (state->start > end)
1117 if (filled && state->start > start) {
1121 if (state->state & bits) {
1125 } else if (filled) {
1129 start = state->end + 1;
1132 node = rb_next(node);
1134 read_unlock_irq(&tree->lock);
1139 * helper function to set a given page up to date if all the
1140 * extents in the tree for that page are up to date
1142 static int check_page_uptodate(struct extent_map_tree *tree,
1145 u64 start = page->index << PAGE_CACHE_SHIFT;
1146 u64 end = start + PAGE_CACHE_SIZE - 1;
1147 if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1))
1148 SetPageUptodate(page);
1153 * helper function to unlock a page if all the extents in the tree
1154 * for that page are unlocked
1156 static int check_page_locked(struct extent_map_tree *tree,
1159 u64 start = page->index << PAGE_CACHE_SHIFT;
1160 u64 end = start + PAGE_CACHE_SIZE - 1;
1161 if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0))
1167 * helper function to end page writeback if all the extents
1168 * in the tree for that page are done with writeback
1170 static int check_page_writeback(struct extent_map_tree *tree,
1173 u64 start = page->index << PAGE_CACHE_SHIFT;
1174 u64 end = start + PAGE_CACHE_SIZE - 1;
1175 if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0))
1176 end_page_writeback(page);
1180 /* lots and lots of room for performance fixes in the end_bio funcs */
1183 * after a writepage IO is done, we need to:
1184 * clear the uptodate bits on error
1185 * clear the writeback bits in the extent tree for this IO
1186 * end_page_writeback if the page has no more pending IO
1188 * Scheduling is not allowed, so the extent state tree is expected
1189 * to have one and only one object corresponding to this IO.
1191 static int end_bio_extent_writepage(struct bio *bio,
1192 unsigned int bytes_done, int err)
1194 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1195 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1196 struct extent_map_tree *tree = bio->bi_private;
1205 struct page *page = bvec->bv_page;
1206 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1207 end = start + bvec->bv_len - 1;
1209 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1214 if (--bvec >= bio->bi_io_vec)
1215 prefetchw(&bvec->bv_page->flags);
1218 clear_extent_uptodate(tree, start, end, GFP_ATOMIC);
1219 ClearPageUptodate(page);
1222 clear_extent_writeback(tree, start, end, GFP_ATOMIC);
1225 end_page_writeback(page);
1227 check_page_writeback(tree, page);
1228 } while (bvec >= bio->bi_io_vec);
1235 * after a readpage IO is done, we need to:
1236 * clear the uptodate bits on error
1237 * set the uptodate bits if things worked
1238 * set the page up to date if all extents in the tree are uptodate
1239 * clear the lock bit in the extent tree
1240 * unlock the page if there are no other extents locked for it
1242 * Scheduling is not allowed, so the extent state tree is expected
1243 * to have one and only one object corresponding to this IO.
1245 static int end_bio_extent_readpage(struct bio *bio,
1246 unsigned int bytes_done, int err)
1248 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1249 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1250 struct extent_map_tree *tree = bio->bi_private;
1260 struct page *page = bvec->bv_page;
1261 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1262 end = start + bvec->bv_len - 1;
1264 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1269 if (--bvec >= bio->bi_io_vec)
1270 prefetchw(&bvec->bv_page->flags);
1272 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1273 ret = tree->ops->readpage_end_io_hook(page, start, end);
1278 set_extent_uptodate(tree, start, end, GFP_ATOMIC);
1280 SetPageUptodate(page);
1282 check_page_uptodate(tree, page);
1284 ClearPageUptodate(page);
1288 unlock_extent(tree, start, end, GFP_ATOMIC);
1293 check_page_locked(tree, page);
1294 } while (bvec >= bio->bi_io_vec);
1301 * IO done from prepare_write is pretty simple, we just unlock
1302 * the structs in the extent tree when done, and set the uptodate bits
1305 static int end_bio_extent_preparewrite(struct bio *bio,
1306 unsigned int bytes_done, int err)
1308 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1309 struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1310 struct extent_map_tree *tree = bio->bi_private;
1318 struct page *page = bvec->bv_page;
1319 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1320 end = start + bvec->bv_len - 1;
1322 if (--bvec >= bio->bi_io_vec)
1323 prefetchw(&bvec->bv_page->flags);
1326 set_extent_uptodate(tree, start, end, GFP_ATOMIC);
1328 ClearPageUptodate(page);
1332 unlock_extent(tree, start, end, GFP_ATOMIC);
1334 } while (bvec >= bio->bi_io_vec);
1340 static int submit_extent_page(int rw, struct extent_map_tree *tree,
1341 struct page *page, sector_t sector,
1342 size_t size, unsigned long offset,
1343 struct block_device *bdev,
1344 bio_end_io_t end_io_func)
1349 bio = bio_alloc(GFP_NOIO, 1);
1351 bio->bi_sector = sector;
1352 bio->bi_bdev = bdev;
1353 bio->bi_io_vec[0].bv_page = page;
1354 bio->bi_io_vec[0].bv_len = size;
1355 bio->bi_io_vec[0].bv_offset = offset;
1359 bio->bi_size = size;
1361 bio->bi_end_io = end_io_func;
1362 bio->bi_private = tree;
1365 submit_bio(rw, bio);
1367 if (bio_flagged(bio, BIO_EOPNOTSUPP))
1375 * basic readpage implementation. Locked extent state structs are inserted
1376 * into the tree that are removed when the IO is done (by the end_io
1379 int extent_read_full_page(struct extent_map_tree *tree, struct page *page,
1380 get_extent_t *get_extent)
1382 struct inode *inode = page->mapping->host;
1383 u64 start = page->index << PAGE_CACHE_SHIFT;
1384 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1388 u64 last_byte = i_size_read(inode);
1392 struct extent_map *em;
1393 struct block_device *bdev;
1396 size_t page_offset = 0;
1398 size_t blocksize = inode->i_sb->s_blocksize;
1400 if (!PagePrivate(page)) {
1401 SetPagePrivate(page);
1402 WARN_ON(!page->mapping->a_ops->invalidatepage);
1403 set_page_private(page, 1);
1404 page_cache_get(page);
1408 lock_extent(tree, start, end, GFP_NOFS);
1410 while (cur <= end) {
1411 if (cur >= last_byte) {
1412 iosize = PAGE_CACHE_SIZE - page_offset;
1413 zero_user_page(page, page_offset, iosize, KM_USER0);
1414 set_extent_uptodate(tree, cur, cur + iosize - 1,
1416 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1419 em = get_extent(inode, page, page_offset, cur, end, 0);
1420 if (IS_ERR(em) || !em) {
1422 unlock_extent(tree, cur, end, GFP_NOFS);
1426 extent_offset = cur - em->start;
1427 BUG_ON(em->end < cur);
1430 iosize = min(em->end - cur, end - cur) + 1;
1431 cur_end = min(em->end, end);
1432 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
1433 sector = (em->block_start + extent_offset) >> 9;
1435 block_start = em->block_start;
1436 free_extent_map(em);
1439 /* we've found a hole, just zero and go on */
1440 if (block_start == 0) {
1441 zero_user_page(page, page_offset, iosize, KM_USER0);
1442 set_extent_uptodate(tree, cur, cur + iosize - 1,
1444 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1446 page_offset += iosize;
1449 /* the get_extent function already copied into the page */
1450 if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) {
1451 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1453 page_offset += iosize;
1458 if (tree->ops && tree->ops->readpage_io_hook) {
1459 ret = tree->ops->readpage_io_hook(page, cur,
1463 ret = submit_extent_page(READ, tree, page,
1464 sector, iosize, page_offset,
1465 bdev, end_bio_extent_readpage);
1470 page_offset += iosize;
1474 if (!PageError(page))
1475 SetPageUptodate(page);
1480 EXPORT_SYMBOL(extent_read_full_page);
1483 * the writepage semantics are similar to regular writepage. extent
1484 * records are inserted to lock ranges in the tree, and as dirty areas
1485 * are found, they are marked writeback. Then the lock bits are removed
1486 * and the end_io handler clears the writeback ranges
1488 int extent_write_full_page(struct extent_map_tree *tree, struct page *page,
1489 get_extent_t *get_extent,
1490 struct writeback_control *wbc)
1492 struct inode *inode = page->mapping->host;
1493 u64 start = page->index << PAGE_CACHE_SHIFT;
1494 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1498 u64 last_byte = i_size_read(inode);
1501 struct extent_map *em;
1502 struct block_device *bdev;
1505 size_t page_offset = 0;
1508 loff_t i_size = i_size_read(inode);
1509 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
1513 WARN_ON(!PageLocked(page));
1514 if (page->index > end_index) {
1515 clear_extent_dirty(tree, start, page_end, GFP_NOFS);
1520 if (page->index == end_index) {
1521 size_t offset = i_size & (PAGE_CACHE_SIZE - 1);
1522 zero_user_page(page, offset,
1523 PAGE_CACHE_SIZE - offset, KM_USER0);
1526 if (!PagePrivate(page)) {
1527 SetPagePrivate(page);
1528 set_page_private(page, 1);
1529 WARN_ON(!page->mapping->a_ops->invalidatepage);
1530 page_cache_get(page);
1533 lock_extent(tree, start, page_end, GFP_NOFS);
1534 nr_delalloc = find_lock_delalloc_range(tree, start, page_end + 1,
1538 tree->ops->fill_delalloc(inode, start, delalloc_end);
1539 if (delalloc_end >= page_end + 1) {
1540 clear_extent_bit(tree, page_end + 1, delalloc_end,
1541 EXTENT_LOCKED | EXTENT_DELALLOC,
1544 clear_extent_bit(tree, start, page_end, EXTENT_DELALLOC,
1546 if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {
1547 printk("found delalloc bits after clear extent_bit\n");
1549 } else if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {
1550 printk("found delalloc bits after find_delalloc_range returns 0\n");
1554 if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {
1555 printk("found delalloc bits after lock_extent\n");
1558 if (last_byte <= start) {
1559 clear_extent_dirty(tree, start, page_end, GFP_NOFS);
1563 set_extent_uptodate(tree, start, page_end, GFP_NOFS);
1564 blocksize = inode->i_sb->s_blocksize;
1566 while (cur <= end) {
1567 if (cur >= last_byte) {
1568 clear_extent_dirty(tree, cur, page_end, GFP_NOFS);
1571 em = get_extent(inode, page, page_offset, cur, end, 0);
1572 if (IS_ERR(em) || !em) {
1577 extent_offset = cur - em->start;
1578 BUG_ON(em->end < cur);
1580 iosize = min(em->end - cur, end - cur) + 1;
1581 iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
1582 sector = (em->block_start + extent_offset) >> 9;
1584 block_start = em->block_start;
1585 free_extent_map(em);
1588 if (block_start == 0 || block_start == EXTENT_MAP_INLINE) {
1589 clear_extent_dirty(tree, cur,
1590 cur + iosize - 1, GFP_NOFS);
1592 page_offset += iosize;
1596 /* leave this out until we have a page_mkwrite call */
1597 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
1600 page_offset += iosize;
1603 clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS);
1604 ret = tree->ops->writepage_io_hook(page, cur, cur + iosize - 1);
1608 set_range_writeback(tree, cur, cur + iosize - 1);
1609 ret = submit_extent_page(WRITE, tree, page, sector,
1610 iosize, page_offset, bdev,
1611 end_bio_extent_writepage);
1616 page_offset += iosize;
1620 WARN_ON(test_range_bit(tree, start, page_end, EXTENT_DIRTY, 0));
1621 unlock_extent(tree, start, page_end, GFP_NOFS);
1625 EXPORT_SYMBOL(extent_write_full_page);
1628 * basic invalidatepage code, this waits on any locked or writeback
1629 * ranges corresponding to the page, and then deletes any extent state
1630 * records from the tree
1632 int extent_invalidatepage(struct extent_map_tree *tree,
1633 struct page *page, unsigned long offset)
1635 u64 start = (page->index << PAGE_CACHE_SHIFT);
1636 u64 end = start + PAGE_CACHE_SIZE - 1;
1637 size_t blocksize = page->mapping->host->i_sb->s_blocksize;
1639 start += (offset + blocksize -1) & ~(blocksize - 1);
1643 lock_extent(tree, start, end, GFP_NOFS);
1644 wait_on_extent_writeback(tree, start, end);
1645 clear_extent_bit(tree, start, end,
1646 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC,
1650 EXPORT_SYMBOL(extent_invalidatepage);
1653 * simple commit_write call, set_range_dirty is used to mark both
1654 * the pages and the extent records as dirty
1656 int extent_commit_write(struct extent_map_tree *tree,
1657 struct inode *inode, struct page *page,
1658 unsigned from, unsigned to)
1660 loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
1662 if (!PagePrivate(page)) {
1663 SetPagePrivate(page);
1664 set_page_private(page, 1);
1665 WARN_ON(!page->mapping->a_ops->invalidatepage);
1666 page_cache_get(page);
1669 set_page_dirty(page);
1671 if (pos > inode->i_size) {
1672 i_size_write(inode, pos);
1673 mark_inode_dirty(inode);
1677 EXPORT_SYMBOL(extent_commit_write);
1679 int extent_prepare_write(struct extent_map_tree *tree,
1680 struct inode *inode, struct page *page,
1681 unsigned from, unsigned to, get_extent_t *get_extent)
1683 u64 page_start = page->index << PAGE_CACHE_SHIFT;
1684 u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
1686 u64 orig_block_start;
1689 struct extent_map *em;
1690 unsigned blocksize = 1 << inode->i_blkbits;
1691 size_t page_offset = 0;
1692 size_t block_off_start;
1693 size_t block_off_end;
1699 if (!PagePrivate(page)) {
1700 SetPagePrivate(page);
1701 set_page_private(page, 1);
1702 WARN_ON(!page->mapping->a_ops->invalidatepage);
1703 page_cache_get(page);
1705 block_start = (page_start + from) & ~((u64)blocksize - 1);
1706 block_end = (page_start + to - 1) | (blocksize - 1);
1707 orig_block_start = block_start;
1709 lock_extent(tree, page_start, page_end, GFP_NOFS);
1710 while(block_start <= block_end) {
1711 em = get_extent(inode, page, page_offset, block_start,
1713 if (IS_ERR(em) || !em) {
1716 cur_end = min(block_end, em->end);
1717 block_off_start = block_start & (PAGE_CACHE_SIZE - 1);
1718 block_off_end = block_off_start + blocksize;
1719 isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS);
1721 if (!PageUptodate(page) && isnew &&
1722 (block_off_end > to || block_off_start < from)) {
1725 kaddr = kmap_atomic(page, KM_USER0);
1726 if (block_off_end > to)
1727 memset(kaddr + to, 0, block_off_end - to);
1728 if (block_off_start < from)
1729 memset(kaddr + block_off_start, 0,
1730 from - block_off_start);
1731 flush_dcache_page(page);
1732 kunmap_atomic(kaddr, KM_USER0);
1734 if (!isnew && !PageUptodate(page) &&
1735 (block_off_end > to || block_off_start < from) &&
1736 !test_range_bit(tree, block_start, cur_end,
1737 EXTENT_UPTODATE, 1)) {
1739 u64 extent_offset = block_start - em->start;
1741 sector = (em->block_start + extent_offset) >> 9;
1742 iosize = (cur_end - block_start + blocksize - 1) &
1743 ~((u64)blocksize - 1);
1745 * we've already got the extent locked, but we
1746 * need to split the state such that our end_bio
1747 * handler can clear the lock.
1749 set_extent_bit(tree, block_start,
1750 block_start + iosize - 1,
1751 EXTENT_LOCKED, 0, NULL, GFP_NOFS);
1752 ret = submit_extent_page(READ, tree, page,
1753 sector, iosize, page_offset, em->bdev,
1754 end_bio_extent_preparewrite);
1756 block_start = block_start + iosize;
1758 set_extent_uptodate(tree, block_start, cur_end,
1760 unlock_extent(tree, block_start, cur_end, GFP_NOFS);
1761 block_start = cur_end + 1;
1763 page_offset = block_start & (PAGE_CACHE_SIZE - 1);
1764 free_extent_map(em);
1767 wait_extent_bit(tree, orig_block_start,
1768 block_end, EXTENT_LOCKED);
1770 check_page_uptodate(tree, page);
1772 /* FIXME, zero out newly allocated blocks on error */
1775 EXPORT_SYMBOL(extent_prepare_write);
1778 * a helper for releasepage. As long as there are no locked extents
1779 * in the range corresponding to the page, both state records and extent
1780 * map records are removed
1782 int try_release_extent_mapping(struct extent_map_tree *tree, struct page *page)
1784 struct extent_map *em;
1785 u64 start = page->index << PAGE_CACHE_SHIFT;
1786 u64 end = start + PAGE_CACHE_SIZE - 1;
1787 u64 orig_start = start;
1790 while (start <= end) {
1791 em = lookup_extent_mapping(tree, start, end);
1792 if (!em || IS_ERR(em))
1794 if (!test_range_bit(tree, em->start, em->end,
1795 EXTENT_LOCKED, 0)) {
1796 remove_extent_mapping(tree, em);
1797 /* once for the rb tree */
1798 free_extent_map(em);
1800 start = em->end + 1;
1802 free_extent_map(em);
1804 if (test_range_bit(tree, orig_start, end, EXTENT_LOCKED, 0))
1807 clear_extent_bit(tree, orig_start, end, EXTENT_UPTODATE,
1811 EXPORT_SYMBOL(try_release_extent_mapping);