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 static LIST_HEAD(all_states);
34 spinlock_t state_lock = SPIN_LOCK_UNLOCKED;
36 void __init extent_map_init(void)
38 extent_map_cache = kmem_cache_create("extent_map",
39 sizeof(struct extent_map), 0,
40 SLAB_RECLAIM_ACCOUNT |
43 extent_state_cache = kmem_cache_create("extent_state",
44 sizeof(struct extent_state), 0,
45 SLAB_RECLAIM_ACCOUNT |
50 void __exit extent_map_exit(void)
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);
62 kmem_cache_destroy(extent_map_cache);
63 if (extent_state_cache)
64 kmem_cache_destroy(extent_state_cache);
67 void extent_map_tree_init(struct extent_map_tree *tree,
68 struct address_space *mapping, gfp_t mask)
70 tree->map.rb_node = NULL;
71 tree->state.rb_node = NULL;
72 rwlock_init(&tree->lock);
73 tree->mapping = mapping;
75 EXPORT_SYMBOL(extent_map_tree_init);
77 struct extent_map *alloc_extent_map(gfp_t mask)
79 struct extent_map *em;
80 em = kmem_cache_alloc(extent_map_cache, mask);
81 if (!em || IS_ERR(em))
84 atomic_set(&em->refs, 1);
87 EXPORT_SYMBOL(alloc_extent_map);
89 void free_extent_map(struct extent_map *em)
91 if (atomic_dec_and_test(&em->refs)) {
93 kmem_cache_free(extent_map_cache, em);
96 EXPORT_SYMBOL(free_extent_map);
99 struct extent_state *alloc_extent_state(gfp_t mask)
101 struct extent_state *state;
102 state = kmem_cache_alloc(extent_state_cache, mask);
103 if (!state || IS_ERR(state))
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);
114 EXPORT_SYMBOL(alloc_extent_state);
116 void free_extent_state(struct extent_state *state)
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);
126 EXPORT_SYMBOL(free_extent_state);
128 static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
129 struct rb_node *node)
131 struct rb_node ** p = &root->rb_node;
132 struct rb_node * parent = NULL;
133 struct tree_entry *entry;
137 entry = rb_entry(parent, struct tree_entry, rb_node);
139 if (offset < entry->start)
141 else if (offset > entry->end)
147 entry = rb_entry(node, struct tree_entry, rb_node);
149 rb_link_node(node, parent, p);
150 rb_insert_color(node, root);
154 static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
155 struct rb_node **prev_ret)
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;
163 entry = rb_entry(n, struct tree_entry, rb_node);
167 if (offset < entry->start)
169 else if (offset > entry->end)
176 while(prev && offset > prev_entry->end) {
177 prev = rb_next(prev);
178 prev_entry = rb_entry(prev, struct tree_entry, rb_node);
184 static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
186 struct rb_node *prev;
188 ret = __tree_search(root, offset, &prev);
194 static int tree_delete(struct rb_root *root, u64 offset)
196 struct rb_node *node;
197 struct tree_entry *entry;
199 node = __tree_search(root, offset, NULL);
202 entry = rb_entry(node, struct tree_entry, rb_node);
204 rb_erase(node, root);
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).
213 int add_extent_mapping(struct extent_map_tree *tree,
214 struct extent_map *em)
217 struct extent_map *prev = NULL;
220 write_lock_irq(&tree->lock);
221 rb = tree_insert(&tree->map, em->end, &em->rb_node);
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);
228 atomic_inc(&em->refs);
229 if (em->start != 0) {
230 rb = rb_prev(&em->rb_node);
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);
240 free_extent_map(prev);
244 write_unlock_irq(&tree->lock);
247 EXPORT_SYMBOL(add_extent_mapping);
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.
255 struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
258 struct extent_map *em;
259 struct rb_node *rb_node;
261 read_lock_irq(&tree->lock);
262 rb_node = tree_search(&tree->map, start);
267 if (IS_ERR(rb_node)) {
268 em = ERR_PTR(PTR_ERR(rb_node));
271 em = rb_entry(rb_node, struct extent_map, rb_node);
272 if (em->end < start || em->start > end) {
276 atomic_inc(&em->refs);
278 read_unlock_irq(&tree->lock);
281 EXPORT_SYMBOL(lookup_extent_mapping);
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
287 int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
291 write_lock_irq(&tree->lock);
292 ret = tree_delete(&tree->map, em->end);
293 write_unlock_irq(&tree->lock);
296 EXPORT_SYMBOL(remove_extent_mapping);
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).
305 * This should be called with the tree lock held.
307 static int merge_state(struct extent_map_tree *tree,
308 struct extent_state *state)
310 struct extent_state *other;
311 struct rb_node *other_node;
313 if (state->state & EXTENT_IOBITS)
316 other_node = rb_prev(&state->rb_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;
323 rb_erase(&other->rb_node, &tree->state);
324 free_extent_state(other);
327 other_node = rb_next(&state->rb_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;
334 rb_erase(&state->rb_node, &tree->state);
335 free_extent_state(state);
342 * insert an extent_state struct into the tree. 'bits' are set on the
343 * struct before it is inserted.
345 * This may return -EEXIST if the extent is already there, in which case the
346 * state struct is freed.
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).
351 static int insert_state(struct extent_map_tree *tree,
352 struct extent_state *state, u64 start, u64 end,
355 struct rb_node *node;
358 printk("end < start %Lu %Lu\n", end, start);
361 state->state |= bits;
362 state->start = start;
364 if ((end & 4095) == 0) {
365 printk("insert state %Lu %Lu strange end\n", start, end);
368 node = tree_insert(&tree->state, end, &state->rb_node);
370 struct extent_state *found;
371 found = rb_entry(node, struct extent_state, rb_node);
372 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, start, end);
373 free_extent_state(state);
376 merge_state(tree, state);
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.
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 ]
391 * The tree locks are not taken by this function. They need to be held
394 static int split_state(struct extent_map_tree *tree, struct extent_state *orig,
395 struct extent_state *prealloc, u64 split)
397 struct rb_node *node;
398 prealloc->start = orig->start;
399 prealloc->end = split - 1;
400 prealloc->state = orig->state;
402 if ((prealloc->end & 4095) == 0) {
403 printk("insert state %Lu %Lu strange end\n", prealloc->start,
407 node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
409 struct extent_state *found;
410 found = rb_entry(node, struct extent_state, rb_node);
411 printk("found node %Lu %Lu on insert of %Lu %Lu\n", found->start, found->end, prealloc->start, prealloc->end);
412 free_extent_state(prealloc);
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).
423 * If no bits are set on the state struct after clearing things, the
424 * struct is freed and removed from the tree
426 static int clear_state_bit(struct extent_map_tree *tree,
427 struct extent_state *state, int bits, int wake,
430 int ret = state->state & bits;
431 state->state &= ~bits;
434 if (delete || state->state == 0) {
435 if (state->in_tree) {
436 rb_erase(&state->rb_node, &tree->state);
438 free_extent_state(state);
443 merge_state(tree, state);
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.
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).
456 * the range [start, end] is inclusive.
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.
461 int clear_extent_bit(struct extent_map_tree *tree, u64 start, u64 end,
462 int bits, int wake, int delete, gfp_t mask)
464 struct extent_state *state;
465 struct extent_state *prealloc = NULL;
466 struct rb_node *node;
471 if (!prealloc && (mask & __GFP_WAIT)) {
472 prealloc = alloc_extent_state(mask);
477 write_lock_irq(&tree->lock);
479 * this search will find the extents that end after
482 node = tree_search(&tree->state, start);
485 state = rb_entry(node, struct extent_state, rb_node);
486 if (state->start > end)
488 WARN_ON(state->end < start);
491 * | ---- desired range ---- |
493 * | ------------- state -------------- |
495 * We need to split the extent we found, and may flip
496 * bits on second half.
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.
502 * If the extent we found is inside our range, we clear
503 * the desired bit on it.
506 if (state->start < start) {
507 err = split_state(tree, state, prealloc, start);
508 BUG_ON(err == -EEXIST);
512 if (state->end <= end) {
513 start = state->end + 1;
514 set |= clear_state_bit(tree, state, bits,
517 start = state->start;
522 * | ---- desired range ---- |
524 * We need to split the extent, and clear the bit
527 if (state->start <= end && state->end > end) {
528 err = split_state(tree, state, prealloc, end + 1);
529 BUG_ON(err == -EEXIST);
533 set |= clear_state_bit(tree, prealloc, bits,
539 start = state->end + 1;
540 set |= clear_state_bit(tree, state, bits, wake, delete);
544 write_unlock_irq(&tree->lock);
546 free_extent_state(prealloc);
553 write_unlock_irq(&tree->lock);
554 if (mask & __GFP_WAIT)
558 EXPORT_SYMBOL(clear_extent_bit);
560 static int wait_on_state(struct extent_map_tree *tree,
561 struct extent_state *state)
564 prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
565 read_unlock_irq(&tree->lock);
567 read_lock_irq(&tree->lock);
568 finish_wait(&state->wq, &wait);
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
577 int wait_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits)
579 struct extent_state *state;
580 struct rb_node *node;
582 read_lock_irq(&tree->lock);
586 * this search will find all the extents that end after
589 node = tree_search(&tree->state, start);
593 state = rb_entry(node, struct extent_state, rb_node);
595 if (state->start > end)
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);
605 start = state->end + 1;
610 if (need_resched()) {
611 read_unlock_irq(&tree->lock);
613 read_lock_irq(&tree->lock);
617 read_unlock_irq(&tree->lock);
620 EXPORT_SYMBOL(wait_extent_bit);
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.
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.
630 * [start, end] is inclusive
631 * This takes the tree lock.
633 int set_extent_bit(struct extent_map_tree *tree, u64 start, u64 end, int bits,
634 int exclusive, u64 *failed_start, gfp_t mask)
636 struct extent_state *state;
637 struct extent_state *prealloc = NULL;
638 struct rb_node *node;
644 if (!prealloc && (mask & __GFP_WAIT)) {
645 prealloc = alloc_extent_state(mask);
650 write_lock_irq(&tree->lock);
652 * this search will find all the extents that end after
655 node = tree_search(&tree->state, start);
657 err = insert_state(tree, prealloc, start, end, bits);
659 BUG_ON(err == -EEXIST);
663 state = rb_entry(node, struct extent_state, rb_node);
664 last_start = state->start;
665 last_end = state->end;
668 * | ---- desired range ---- |
671 * Just lock what we found and keep going
673 if (state->start == start && state->end <= end) {
674 set = state->state & bits;
675 if (set && exclusive) {
676 *failed_start = state->start;
680 state->state |= bits;
681 start = state->end + 1;
682 merge_state(tree, state);
687 * | ---- desired range ---- |
690 * | ------------- state -------------- |
692 * We need to split the extent we found, and may flip bits on
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.
699 * If the extent we found is inside our range, we set the
702 if (state->start < start) {
703 set = state->state & bits;
704 if (exclusive && set) {
705 *failed_start = start;
709 err = split_state(tree, state, prealloc, start);
710 BUG_ON(err == -EEXIST);
714 if (state->end <= end) {
715 state->state |= bits;
716 start = state->end + 1;
717 merge_state(tree, state);
719 start = state->start;
724 * | ---- desired range ---- |
726 * We need to split the extent, and set the bit
729 if (state->start <= end && state->end > end) {
730 set = state->state & bits;
731 if (exclusive && set) {
732 *failed_start = start;
736 err = split_state(tree, state, prealloc, end + 1);
737 BUG_ON(err == -EEXIST);
739 prealloc->state |= bits;
740 merge_state(tree, prealloc);
746 * | ---- desired range ---- |
747 * | state | or | state |
749 * There's a hole, we need to insert something in it and
750 * ignore the extent we found.
752 if (state->start > start) {
754 if (end < last_start)
757 this_end = last_start -1;
758 err = insert_state(tree, prealloc, start, this_end,
761 BUG_ON(err == -EEXIST);
764 start = this_end + 1;
770 write_unlock_irq(&tree->lock);
772 free_extent_state(prealloc);
779 write_unlock_irq(&tree->lock);
780 if (mask & __GFP_WAIT)
784 EXPORT_SYMBOL(set_extent_bit);
786 /* wrappers around set/clear extent bit */
787 int set_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
790 return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
793 EXPORT_SYMBOL(set_extent_dirty);
795 int clear_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
798 return clear_extent_bit(tree, start, end, EXTENT_DIRTY, 0, 0, mask);
800 EXPORT_SYMBOL(clear_extent_dirty);
802 int set_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
805 return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
808 EXPORT_SYMBOL(set_extent_new);
810 int clear_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
813 return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask);
815 EXPORT_SYMBOL(clear_extent_new);
817 int set_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
820 return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
823 EXPORT_SYMBOL(set_extent_uptodate);
825 int clear_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
828 return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask);
830 EXPORT_SYMBOL(clear_extent_uptodate);
832 int set_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end,
835 return set_extent_bit(tree, start, end, EXTENT_WRITEBACK,
838 EXPORT_SYMBOL(set_extent_writeback);
840 int clear_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end,
843 return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask);
845 EXPORT_SYMBOL(clear_extent_writeback);
847 int wait_on_extent_writeback(struct extent_map_tree *tree, u64 start, u64 end)
849 return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
851 EXPORT_SYMBOL(wait_on_extent_writeback);
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.
857 int lock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask)
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;
870 WARN_ON(start > end);
874 EXPORT_SYMBOL(lock_extent);
876 int unlock_extent(struct extent_map_tree *tree, u64 start, u64 end,
879 return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask);
881 EXPORT_SYMBOL(unlock_extent);
884 * helper function to set pages and extents in the tree dirty
886 int set_range_dirty(struct extent_map_tree *tree, u64 start, u64 end)
888 unsigned long index = start >> PAGE_CACHE_SHIFT;
889 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
892 while (index <= end_index) {
893 page = find_get_page(tree->mapping, index);
895 __set_page_dirty_nobuffers(page);
896 page_cache_release(page);
899 set_extent_dirty(tree, start, end, GFP_NOFS);
902 EXPORT_SYMBOL(set_range_dirty);
905 * helper function to set both pages and extents in the tree writeback
907 int set_range_writeback(struct extent_map_tree *tree, u64 start, u64 end)
909 unsigned long index = start >> PAGE_CACHE_SHIFT;
910 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
913 while (index <= end_index) {
914 page = find_get_page(tree->mapping, index);
916 set_page_writeback(page);
917 page_cache_release(page);
920 set_extent_writeback(tree, start, end, GFP_NOFS);
923 EXPORT_SYMBOL(set_range_writeback);
926 * helper function to lock both pages and extents in the tree.
927 * pages must be locked first.
929 int lock_range(struct extent_map_tree *tree, u64 start, u64 end)
931 unsigned long index = start >> PAGE_CACHE_SHIFT;
932 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
936 while (index <= end_index) {
937 page = grab_cache_page(tree->mapping, index);
948 lock_extent(tree, start, end, GFP_NOFS);
953 * we failed above in getting the page at 'index', so we undo here
954 * up to but not including the page at 'index'
957 index = start >> PAGE_CACHE_SHIFT;
958 while (index < end_index) {
959 page = find_get_page(tree->mapping, index);
961 page_cache_release(page);
966 EXPORT_SYMBOL(lock_range);
969 * helper function to unlock both pages and extents in the tree.
971 int unlock_range(struct extent_map_tree *tree, u64 start, u64 end)
973 unsigned long index = start >> PAGE_CACHE_SHIFT;
974 unsigned long end_index = end >> PAGE_CACHE_SHIFT;
977 while (index <= end_index) {
978 page = find_get_page(tree->mapping, index);
980 page_cache_release(page);
983 unlock_extent(tree, start, end, GFP_NOFS);
986 EXPORT_SYMBOL(unlock_range);
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.
994 static int test_range_bit(struct extent_map_tree *tree, u64 start, u64 end,
995 int bits, int filled)
997 struct extent_state *state = NULL;
998 struct rb_node *node;
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)
1008 if (filled && state->start > start) {
1012 if (state->state & bits) {
1016 } else if (filled) {
1020 start = state->end + 1;
1023 node = rb_next(node);
1025 read_unlock_irq(&tree->lock);
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
1033 static int check_page_uptodate(struct extent_map_tree *tree,
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);
1044 * helper function to unlock a page if all the extents in the tree
1045 * for that page are unlocked
1047 static int check_page_locked(struct extent_map_tree *tree,
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))
1058 * helper function to end page writeback if all the extents
1059 * in the tree for that page are done with writeback
1061 static int check_page_writeback(struct extent_map_tree *tree,
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);
1071 /* lots and lots of room for performance fixes in the end_bio funcs */
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
1079 * Scheduling is not allowed, so the extent state tree is expected
1080 * to have one and only one object corresponding to this IO.
1082 static int end_bio_extent_writepage(struct bio *bio,
1083 unsigned int bytes_done, int err)
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;
1096 struct page *page = bvec->bv_page;
1097 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1098 end = start + bvec->bv_len - 1;
1100 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1105 if (--bvec >= bio->bi_io_vec)
1106 prefetchw(&bvec->bv_page->flags);
1109 clear_extent_uptodate(tree, start, end, GFP_ATOMIC);
1110 ClearPageUptodate(page);
1113 clear_extent_writeback(tree, start, end, GFP_ATOMIC);
1116 end_page_writeback(page);
1118 check_page_writeback(tree, page);
1119 } while (bvec >= bio->bi_io_vec);
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
1133 * Scheduling is not allowed, so the extent state tree is expected
1134 * to have one and only one object corresponding to this IO.
1136 static int end_bio_extent_readpage(struct bio *bio,
1137 unsigned int bytes_done, int err)
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;
1150 struct page *page = bvec->bv_page;
1151 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1152 end = start + bvec->bv_len - 1;
1154 if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
1159 if (--bvec >= bio->bi_io_vec)
1160 prefetchw(&bvec->bv_page->flags);
1163 set_extent_uptodate(tree, start, end, GFP_ATOMIC);
1165 SetPageUptodate(page);
1167 check_page_uptodate(tree, page);
1169 ClearPageUptodate(page);
1173 unlock_extent(tree, start, end, GFP_ATOMIC);
1178 check_page_locked(tree, page);
1179 } while (bvec >= bio->bi_io_vec);
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
1190 static int end_bio_extent_preparewrite(struct bio *bio,
1191 unsigned int bytes_done, int err)
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;
1203 struct page *page = bvec->bv_page;
1204 start = (page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
1205 end = start + bvec->bv_len - 1;
1207 if (--bvec >= bio->bi_io_vec)
1208 prefetchw(&bvec->bv_page->flags);
1211 set_extent_uptodate(tree, start, end, GFP_ATOMIC);
1213 ClearPageUptodate(page);
1217 unlock_extent(tree, start, end, GFP_ATOMIC);
1219 } while (bvec >= bio->bi_io_vec);
1225 static 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)
1234 bio = bio_alloc(GFP_NOIO, 1);
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;
1244 bio->bi_size = size;
1246 bio->bi_end_io = end_io_func;
1247 bio->bi_private = tree;
1250 submit_bio(rw, bio);
1252 if (bio_flagged(bio, BIO_EOPNOTSUPP))
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
1264 int extent_read_full_page(struct extent_map_tree *tree, struct page *page,
1265 get_extent_t *get_extent)
1267 struct inode *inode = page->mapping->host;
1268 u64 start = page->index << PAGE_CACHE_SHIFT;
1269 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1273 u64 last_byte = i_size_read(inode);
1277 struct extent_map *em;
1278 struct block_device *bdev;
1281 size_t page_offset = 0;
1283 size_t blocksize = inode->i_sb->s_blocksize;
1285 if (!PagePrivate(page)) {
1286 SetPagePrivate(page);
1287 set_page_private(page, 1);
1288 page_cache_get(page);
1292 lock_extent(tree, start, end, GFP_NOFS);
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,
1300 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1303 em = get_extent(inode, page, page_offset, cur, end, 0);
1304 if (IS_ERR(em) || !em) {
1306 unlock_extent(tree, cur, end, GFP_NOFS);
1310 extent_offset = cur - em->start;
1311 BUG_ON(em->end < cur);
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;
1319 block_start = em->block_start;
1320 free_extent_map(em);
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,
1328 unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
1330 page_offset += iosize;
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);
1337 page_offset += iosize;
1341 ret = submit_extent_page(READ, tree, page,
1342 sector, iosize, page_offset, bdev,
1343 end_bio_extent_readpage);
1347 page_offset += iosize;
1351 if (!PageError(page))
1352 SetPageUptodate(page);
1357 EXPORT_SYMBOL(extent_read_full_page);
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
1365 int extent_write_full_page(struct extent_map_tree *tree, struct page *page,
1366 get_extent_t *get_extent,
1367 struct writeback_control *wbc)
1369 struct inode *inode = page->mapping->host;
1370 u64 start = page->index << PAGE_CACHE_SHIFT;
1371 u64 page_end = start + PAGE_CACHE_SIZE - 1;
1375 u64 last_byte = i_size_read(inode);
1378 struct extent_map *em;
1379 struct block_device *bdev;
1382 size_t page_offset = 0;
1385 loff_t i_size = i_size_read(inode);
1386 unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
1388 if (page->index > end_index) {
1389 clear_extent_dirty(tree, start, page_end, GFP_NOFS);
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);
1400 if (!PagePrivate(page)) {
1401 SetPagePrivate(page);
1402 set_page_private(page, 1);
1403 page_cache_get(page);
1407 lock_extent(tree, start, page_end, GFP_NOFS);
1409 if (last_byte <= start) {
1410 clear_extent_dirty(tree, start, page_end, GFP_NOFS);
1414 set_extent_uptodate(tree, start, page_end, GFP_NOFS);
1415 blocksize = inode->i_sb->s_blocksize;
1417 while (cur <= end) {
1418 if (cur >= last_byte) {
1419 clear_extent_dirty(tree, cur, page_end, GFP_NOFS);
1422 em = get_extent(inode, page, page_offset, cur, end, 1);
1423 if (IS_ERR(em) || !em) {
1428 extent_offset = cur - em->start;
1429 BUG_ON(em->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;
1435 block_start = em->block_start;
1436 free_extent_map(em);
1439 if (block_start == 0 || block_start == EXTENT_MAP_INLINE) {
1440 clear_extent_dirty(tree, cur,
1441 cur + iosize - 1, GFP_NOFS);
1443 page_offset += iosize;
1447 /* leave this out until we have a page_mkwrite call */
1448 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
1451 page_offset += iosize;
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);
1462 page_offset += iosize;
1466 WARN_ON(test_range_bit(tree, start, page_end, EXTENT_DIRTY, 0));
1467 unlock_extent(tree, start, page_end, GFP_NOFS);
1471 EXPORT_SYMBOL(extent_write_full_page);
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
1478 int extent_invalidatepage(struct extent_map_tree *tree,
1479 struct page *page, unsigned long offset)
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;
1485 start += (offset + blocksize -1) & ~(blocksize - 1);
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,
1495 EXPORT_SYMBOL(extent_invalidatepage);
1498 * simple commit_write call, set_range_dirty is used to mark both
1499 * the pages and the extent records as dirty
1501 int extent_commit_write(struct extent_map_tree *tree,
1502 struct inode *inode, struct page *page,
1503 unsigned from, unsigned to)
1505 loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
1507 if (!PagePrivate(page)) {
1508 SetPagePrivate(page);
1509 set_page_private(page, 1);
1510 page_cache_get(page);
1513 set_page_dirty(page);
1515 if (pos > inode->i_size) {
1516 i_size_write(inode, pos);
1517 mark_inode_dirty(inode);
1521 EXPORT_SYMBOL(extent_commit_write);
1523 int 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)
1527 u64 page_start = page->index << PAGE_CACHE_SHIFT;
1528 u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
1530 u64 orig_block_start;
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;
1543 if (!PagePrivate(page)) {
1544 SetPagePrivate(page);
1545 set_page_private(page, 1);
1546 page_cache_get(page);
1548 block_start = (page_start + from) & ~((u64)blocksize - 1);
1549 block_end = (page_start + to - 1) | (blocksize - 1);
1550 orig_block_start = block_start;
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,
1556 if (IS_ERR(em) || !em) {
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);
1564 if (!PageUptodate(page) && isnew &&
1565 (block_off_end > to || block_off_start < from)) {
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);
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)) {
1582 u64 extent_offset = block_start - em->start;
1584 sector = (em->block_start + extent_offset) >> 9;
1585 iosize = (cur_end - block_start + blocksize - 1) &
1586 ~((u64)blocksize - 1);
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.
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);
1599 block_start = block_start + iosize;
1601 set_extent_uptodate(tree, block_start, cur_end,
1603 unlock_extent(tree, block_start, cur_end, GFP_NOFS);
1604 block_start = cur_end + 1;
1606 page_offset = block_start & (PAGE_CACHE_SIZE - 1);
1607 free_extent_map(em);
1610 wait_extent_bit(tree, orig_block_start,
1611 block_end, EXTENT_LOCKED);
1613 check_page_uptodate(tree, page);
1615 /* FIXME, zero out newly allocated blocks on error */
1618 EXPORT_SYMBOL(extent_prepare_write);
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
1625 int try_release_extent_mapping(struct extent_map_tree *tree, struct page *page)
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;
1632 while (start <= end) {
1633 em = lookup_extent_mapping(tree, start, end);
1634 if (!em || IS_ERR(em))
1636 if (test_range_bit(tree, em->start, em->end,
1637 EXTENT_LOCKED, 0)) {
1638 free_extent_map(em);
1639 start = em->end + 1;
1640 printk("range still locked %Lu %Lu\n", em->start, em->end);
1643 remove_extent_mapping(tree, em);
1644 start = em->end + 1;
1645 /* once for the rb tree */
1646 free_extent_map(em);
1648 free_extent_map(em);
1650 WARN_ON(test_range_bit(tree, orig_start, end, EXTENT_WRITEBACK, 0));
1651 clear_extent_bit(tree, orig_start, end, EXTENT_UPTODATE,
1655 EXPORT_SYMBOL(try_release_extent_mapping);