1 // SPDX-License-Identifier: GPL-2.0
4 #include <linux/slab.h>
5 #include <linux/spinlock.h>
9 #include "extent_map.h"
10 #include "compression.h"
11 #include "btrfs_inode.h"
14 static struct kmem_cache *extent_map_cache;
16 int __init extent_map_init(void)
18 extent_map_cache = kmem_cache_create("btrfs_extent_map",
19 sizeof(struct extent_map), 0,
20 SLAB_MEM_SPREAD, NULL);
21 if (!extent_map_cache)
26 void __cold extent_map_exit(void)
28 kmem_cache_destroy(extent_map_cache);
32 * Initialize the extent tree @tree. Should be called for each new inode or
33 * other user of the extent_map interface.
35 void extent_map_tree_init(struct extent_map_tree *tree)
37 tree->map = RB_ROOT_CACHED;
38 INIT_LIST_HEAD(&tree->modified_extents);
39 rwlock_init(&tree->lock);
43 * Allocate a new extent_map structure. The new structure is returned with a
44 * reference count of one and needs to be freed using free_extent_map()
46 struct extent_map *alloc_extent_map(void)
48 struct extent_map *em;
49 em = kmem_cache_zalloc(extent_map_cache, GFP_NOFS);
52 RB_CLEAR_NODE(&em->rb_node);
53 refcount_set(&em->refs, 1);
54 INIT_LIST_HEAD(&em->list);
59 * Drop the reference out on @em by one and free the structure if the reference
62 void free_extent_map(struct extent_map *em)
66 if (refcount_dec_and_test(&em->refs)) {
67 WARN_ON(extent_map_in_tree(em));
68 WARN_ON(!list_empty(&em->list));
69 kmem_cache_free(extent_map_cache, em);
73 /* Do the math around the end of an extent, handling wrapping. */
74 static u64 range_end(u64 start, u64 len)
76 if (start + len < start)
81 static int tree_insert(struct rb_root_cached *root, struct extent_map *em)
83 struct rb_node **p = &root->rb_root.rb_node;
84 struct rb_node *parent = NULL;
85 struct extent_map *entry = NULL;
86 struct rb_node *orig_parent = NULL;
87 u64 end = range_end(em->start, em->len);
92 entry = rb_entry(parent, struct extent_map, rb_node);
94 if (em->start < entry->start) {
96 } else if (em->start >= extent_map_end(entry)) {
104 orig_parent = parent;
105 while (parent && em->start >= extent_map_end(entry)) {
106 parent = rb_next(parent);
107 entry = rb_entry(parent, struct extent_map, rb_node);
110 if (end > entry->start && em->start < extent_map_end(entry))
113 parent = orig_parent;
114 entry = rb_entry(parent, struct extent_map, rb_node);
115 while (parent && em->start < entry->start) {
116 parent = rb_prev(parent);
117 entry = rb_entry(parent, struct extent_map, rb_node);
120 if (end > entry->start && em->start < extent_map_end(entry))
123 rb_link_node(&em->rb_node, orig_parent, p);
124 rb_insert_color_cached(&em->rb_node, root, leftmost);
129 * Search through the tree for an extent_map with a given offset. If it can't
130 * be found, try to find some neighboring extents
132 static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
133 struct rb_node **prev_or_next_ret)
135 struct rb_node *n = root->rb_node;
136 struct rb_node *prev = NULL;
137 struct rb_node *orig_prev = NULL;
138 struct extent_map *entry;
139 struct extent_map *prev_entry = NULL;
141 ASSERT(prev_or_next_ret);
144 entry = rb_entry(n, struct extent_map, rb_node);
148 if (offset < entry->start)
150 else if (offset >= extent_map_end(entry))
157 while (prev && offset >= extent_map_end(prev_entry)) {
158 prev = rb_next(prev);
159 prev_entry = rb_entry(prev, struct extent_map, rb_node);
163 * Previous extent map found, return as in this case the caller does not
164 * care about the next one.
167 *prev_or_next_ret = prev;
172 prev_entry = rb_entry(prev, struct extent_map, rb_node);
173 while (prev && offset < prev_entry->start) {
174 prev = rb_prev(prev);
175 prev_entry = rb_entry(prev, struct extent_map, rb_node);
177 *prev_or_next_ret = prev;
182 static inline u64 extent_map_block_end(const struct extent_map *em)
184 if (em->block_start + em->block_len < em->block_start)
186 return em->block_start + em->block_len;
189 static bool can_merge_extent_map(const struct extent_map *em)
191 if (em->flags & EXTENT_FLAG_PINNED)
194 /* Don't merge compressed extents, we need to know their actual size. */
195 if (extent_map_is_compressed(em))
198 if (em->flags & EXTENT_FLAG_LOGGING)
202 * We don't want to merge stuff that hasn't been written to the log yet
203 * since it may not reflect exactly what is on disk, and that would be
206 if (!list_empty(&em->list))
212 /* Check to see if two extent_map structs are adjacent and safe to merge. */
213 static bool mergeable_maps(const struct extent_map *prev, const struct extent_map *next)
215 if (extent_map_end(prev) != next->start)
218 if (prev->flags != next->flags)
221 if (next->block_start < EXTENT_MAP_LAST_BYTE - 1)
222 return next->block_start == extent_map_block_end(prev);
224 /* HOLES and INLINE extents. */
225 return next->block_start == prev->block_start;
228 static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
230 struct extent_map *merge = NULL;
234 * We can't modify an extent map that is in the tree and that is being
235 * used by another task, as it can cause that other task to see it in
236 * inconsistent state during the merging. We always have 1 reference for
237 * the tree and 1 for this task (which is unpinning the extent map or
238 * clearing the logging flag), so anything > 2 means it's being used by
241 if (refcount_read(&em->refs) > 2)
244 if (!can_merge_extent_map(em))
247 if (em->start != 0) {
248 rb = rb_prev(&em->rb_node);
250 merge = rb_entry(rb, struct extent_map, rb_node);
251 if (rb && can_merge_extent_map(merge) && mergeable_maps(merge, em)) {
252 em->start = merge->start;
253 em->orig_start = merge->orig_start;
254 em->len += merge->len;
255 em->block_len += merge->block_len;
256 em->block_start = merge->block_start;
257 em->mod_len = (em->mod_len + em->mod_start) - merge->mod_start;
258 em->mod_start = merge->mod_start;
259 em->generation = max(em->generation, merge->generation);
260 em->flags |= EXTENT_FLAG_MERGED;
262 rb_erase_cached(&merge->rb_node, &tree->map);
263 RB_CLEAR_NODE(&merge->rb_node);
264 free_extent_map(merge);
268 rb = rb_next(&em->rb_node);
270 merge = rb_entry(rb, struct extent_map, rb_node);
271 if (rb && can_merge_extent_map(merge) && mergeable_maps(em, merge)) {
272 em->len += merge->len;
273 em->block_len += merge->block_len;
274 rb_erase_cached(&merge->rb_node, &tree->map);
275 RB_CLEAR_NODE(&merge->rb_node);
276 em->mod_len = (merge->mod_start + merge->mod_len) - em->mod_start;
277 em->generation = max(em->generation, merge->generation);
278 em->flags |= EXTENT_FLAG_MERGED;
279 free_extent_map(merge);
284 * Unpin an extent from the cache.
286 * @inode: the inode from which we are unpinning an extent range
287 * @start: logical offset in the file
288 * @len: length of the extent
289 * @gen: generation that this extent has been modified in
291 * Called after an extent has been written to disk properly. Set the generation
292 * to the generation that actually added the file item to the inode so we know
293 * we need to sync this extent when we call fsync().
295 * Returns: 0 on success
296 * -ENOENT when the extent is not found in the tree
297 * -EUCLEAN if the found extent does not match the expected start
299 int unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len, u64 gen)
301 struct btrfs_fs_info *fs_info = inode->root->fs_info;
302 struct extent_map_tree *tree = &inode->extent_tree;
304 struct extent_map *em;
305 bool prealloc = false;
307 write_lock(&tree->lock);
308 em = lookup_extent_mapping(tree, start, len);
312 "no extent map found for inode %llu (root %lld) when unpinning extent range [%llu, %llu), generation %llu",
313 btrfs_ino(inode), btrfs_root_id(inode->root),
314 start, start + len, gen);
319 if (WARN_ON(em->start != start)) {
321 "found extent map for inode %llu (root %lld) with unexpected start offset %llu when unpinning extent range [%llu, %llu), generation %llu",
322 btrfs_ino(inode), btrfs_root_id(inode->root),
323 em->start, start, start + len, gen);
328 em->generation = gen;
329 em->flags &= ~EXTENT_FLAG_PINNED;
330 em->mod_start = em->start;
331 em->mod_len = em->len;
333 if (em->flags & EXTENT_FLAG_FILLING) {
335 em->flags &= ~EXTENT_FLAG_FILLING;
338 try_merge_map(tree, em);
341 em->mod_start = em->start;
342 em->mod_len = em->len;
346 write_unlock(&tree->lock);
352 void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em)
354 lockdep_assert_held_write(&tree->lock);
356 em->flags &= ~EXTENT_FLAG_LOGGING;
357 if (extent_map_in_tree(em))
358 try_merge_map(tree, em);
361 static inline void setup_extent_mapping(struct extent_map_tree *tree,
362 struct extent_map *em,
365 refcount_inc(&em->refs);
366 em->mod_start = em->start;
367 em->mod_len = em->len;
369 ASSERT(list_empty(&em->list));
372 list_add(&em->list, &tree->modified_extents);
374 try_merge_map(tree, em);
378 * Add new extent map to the extent tree
380 * @tree: tree to insert new map in
382 * @modified: indicate whether the given @em should be added to the
383 * modified list, which indicates the extent needs to be logged
385 * Insert @em into @tree or perform a simple forward/backward merge with
386 * existing mappings. The extent_map struct passed in will be inserted
387 * into the tree directly, with an additional reference taken, or a
388 * reference dropped if the merge attempt was successful.
390 static int add_extent_mapping(struct extent_map_tree *tree,
391 struct extent_map *em, int modified)
395 lockdep_assert_held_write(&tree->lock);
397 ret = tree_insert(&tree->map, em);
401 setup_extent_mapping(tree, em, modified);
406 static struct extent_map *
407 __lookup_extent_mapping(struct extent_map_tree *tree,
408 u64 start, u64 len, int strict)
410 struct extent_map *em;
411 struct rb_node *rb_node;
412 struct rb_node *prev_or_next = NULL;
413 u64 end = range_end(start, len);
415 rb_node = __tree_search(&tree->map.rb_root, start, &prev_or_next);
418 rb_node = prev_or_next;
423 em = rb_entry(rb_node, struct extent_map, rb_node);
425 if (strict && !(end > em->start && start < extent_map_end(em)))
428 refcount_inc(&em->refs);
433 * Lookup extent_map that intersects @start + @len range.
435 * @tree: tree to lookup in
436 * @start: byte offset to start the search
437 * @len: length of the lookup range
439 * Find and return the first extent_map struct in @tree that intersects the
440 * [start, len] range. There may be additional objects in the tree that
441 * intersect, so check the object returned carefully to make sure that no
442 * additional lookups are needed.
444 struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
447 return __lookup_extent_mapping(tree, start, len, 1);
451 * Find a nearby extent map intersecting @start + @len (not an exact search).
453 * @tree: tree to lookup in
454 * @start: byte offset to start the search
455 * @len: length of the lookup range
457 * Find and return the first extent_map struct in @tree that intersects the
458 * [start, len] range.
460 * If one can't be found, any nearby extent may be returned
462 struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
465 return __lookup_extent_mapping(tree, start, len, 0);
469 * Remove an extent_map from the extent tree.
471 * @tree: extent tree to remove from
472 * @em: extent map being removed
474 * Remove @em from @tree. No reference counts are dropped, and no checks
475 * are done to see if the range is in use.
477 void remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
479 lockdep_assert_held_write(&tree->lock);
481 WARN_ON(em->flags & EXTENT_FLAG_PINNED);
482 rb_erase_cached(&em->rb_node, &tree->map);
483 if (!(em->flags & EXTENT_FLAG_LOGGING))
484 list_del_init(&em->list);
485 RB_CLEAR_NODE(&em->rb_node);
488 static void replace_extent_mapping(struct extent_map_tree *tree,
489 struct extent_map *cur,
490 struct extent_map *new,
493 lockdep_assert_held_write(&tree->lock);
495 WARN_ON(cur->flags & EXTENT_FLAG_PINNED);
496 ASSERT(extent_map_in_tree(cur));
497 if (!(cur->flags & EXTENT_FLAG_LOGGING))
498 list_del_init(&cur->list);
499 rb_replace_node_cached(&cur->rb_node, &new->rb_node, &tree->map);
500 RB_CLEAR_NODE(&cur->rb_node);
502 setup_extent_mapping(tree, new, modified);
505 static struct extent_map *next_extent_map(const struct extent_map *em)
507 struct rb_node *next;
509 next = rb_next(&em->rb_node);
512 return container_of(next, struct extent_map, rb_node);
515 static struct extent_map *prev_extent_map(struct extent_map *em)
517 struct rb_node *prev;
519 prev = rb_prev(&em->rb_node);
522 return container_of(prev, struct extent_map, rb_node);
526 * Helper for btrfs_get_extent. Given an existing extent in the tree,
527 * the existing extent is the nearest extent to map_start,
528 * and an extent that you want to insert, deal with overlap and insert
529 * the best fitted new extent into the tree.
531 static noinline int merge_extent_mapping(struct extent_map_tree *em_tree,
532 struct extent_map *existing,
533 struct extent_map *em,
536 struct extent_map *prev;
537 struct extent_map *next;
542 BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
544 if (existing->start > map_start) {
546 prev = prev_extent_map(next);
549 next = next_extent_map(prev);
552 start = prev ? extent_map_end(prev) : em->start;
553 start = max_t(u64, start, em->start);
554 end = next ? next->start : extent_map_end(em);
555 end = min_t(u64, end, extent_map_end(em));
556 start_diff = start - em->start;
558 em->len = end - start;
559 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
560 !extent_map_is_compressed(em)) {
561 em->block_start += start_diff;
562 em->block_len = em->len;
564 return add_extent_mapping(em_tree, em, 0);
568 * Add extent mapping into em_tree.
570 * @fs_info: the filesystem
571 * @em_tree: extent tree into which we want to insert the extent mapping
572 * @em_in: extent we are inserting
573 * @start: start of the logical range btrfs_get_extent() is requesting
574 * @len: length of the logical range btrfs_get_extent() is requesting
576 * Note that @em_in's range may be different from [start, start+len),
577 * but they must be overlapped.
579 * Insert @em_in into @em_tree. In case there is an overlapping range, handle
580 * the -EEXIST by either:
581 * a) Returning the existing extent in @em_in if @start is within the
583 * b) Merge the existing extent with @em_in passed in.
585 * Return 0 on success, otherwise -EEXIST.
588 int btrfs_add_extent_mapping(struct btrfs_fs_info *fs_info,
589 struct extent_map_tree *em_tree,
590 struct extent_map **em_in, u64 start, u64 len)
593 struct extent_map *em = *em_in;
596 * Tree-checker should have rejected any inline extent with non-zero
597 * file offset. Here just do a sanity check.
599 if (em->block_start == EXTENT_MAP_INLINE)
600 ASSERT(em->start == 0);
602 ret = add_extent_mapping(em_tree, em, 0);
603 /* it is possible that someone inserted the extent into the tree
604 * while we had the lock dropped. It is also possible that
605 * an overlapping map exists in the tree
607 if (ret == -EEXIST) {
608 struct extent_map *existing;
610 existing = search_extent_mapping(em_tree, start, len);
612 trace_btrfs_handle_em_exist(fs_info, existing, em, start, len);
615 * existing will always be non-NULL, since there must be
616 * extent causing the -EEXIST.
618 if (start >= existing->start &&
619 start < extent_map_end(existing)) {
624 u64 orig_start = em->start;
625 u64 orig_len = em->len;
628 * The existing extent map is the one nearest to
629 * the [start, start + len) range which overlaps
631 ret = merge_extent_mapping(em_tree, existing,
637 "unexpected error %d: merge existing(start %llu len %llu) with em(start %llu len %llu)\n",
638 ret, existing->start, existing->len,
639 orig_start, orig_len);
641 free_extent_map(existing);
645 ASSERT(ret == 0 || ret == -EEXIST);
650 * Drop all extent maps from a tree in the fastest possible way, rescheduling
651 * if needed. This avoids searching the tree, from the root down to the first
652 * extent map, before each deletion.
654 static void drop_all_extent_maps_fast(struct extent_map_tree *tree)
656 write_lock(&tree->lock);
657 while (!RB_EMPTY_ROOT(&tree->map.rb_root)) {
658 struct extent_map *em;
659 struct rb_node *node;
661 node = rb_first_cached(&tree->map);
662 em = rb_entry(node, struct extent_map, rb_node);
663 em->flags &= ~(EXTENT_FLAG_PINNED | EXTENT_FLAG_LOGGING);
664 remove_extent_mapping(tree, em);
666 cond_resched_rwlock_write(&tree->lock);
668 write_unlock(&tree->lock);
672 * Drop all extent maps in a given range.
674 * @inode: The target inode.
675 * @start: Start offset of the range.
676 * @end: End offset of the range (inclusive value).
677 * @skip_pinned: Indicate if pinned extent maps should be ignored or not.
679 * This drops all the extent maps that intersect the given range [@start, @end].
680 * Extent maps that partially overlap the range and extend behind or beyond it,
682 * The caller should have locked an appropriate file range in the inode's io
683 * tree before calling this function.
685 void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end,
688 struct extent_map *split;
689 struct extent_map *split2;
690 struct extent_map *em;
691 struct extent_map_tree *em_tree = &inode->extent_tree;
692 u64 len = end - start + 1;
694 WARN_ON(end < start);
695 if (end == (u64)-1) {
696 if (start == 0 && !skip_pinned) {
697 drop_all_extent_maps_fast(em_tree);
702 /* Make end offset exclusive for use in the loop below. */
707 * It's ok if we fail to allocate the extent maps, see the comment near
708 * the bottom of the loop below. We only need two spare extent maps in
709 * the worst case, where the first extent map that intersects our range
710 * starts before the range and the last extent map that intersects our
711 * range ends after our range (and they might be the same extent map),
712 * because we need to split those two extent maps at the boundaries.
714 split = alloc_extent_map();
715 split2 = alloc_extent_map();
717 write_lock(&em_tree->lock);
718 em = lookup_extent_mapping(em_tree, start, len);
721 /* extent_map_end() returns exclusive value (last byte + 1). */
722 const u64 em_end = extent_map_end(em);
723 struct extent_map *next_em = NULL;
730 next_em = next_extent_map(em);
732 if (next_em->start < end)
733 refcount_inc(&next_em->refs);
739 if (skip_pinned && (em->flags & EXTENT_FLAG_PINNED)) {
746 * In case we split the extent map, we want to preserve the
747 * EXTENT_FLAG_LOGGING flag on our extent map, but we don't want
748 * it on the new extent maps.
750 em->flags &= ~(EXTENT_FLAG_PINNED | EXTENT_FLAG_LOGGING);
751 modified = !list_empty(&em->list);
754 * The extent map does not cross our target range, so no need to
755 * split it, we can remove it directly.
757 if (em->start >= start && em_end <= end)
760 gen = em->generation;
761 compressed = extent_map_is_compressed(em);
763 if (em->start < start) {
770 split->start = em->start;
771 split->len = start - em->start;
773 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
774 split->orig_start = em->orig_start;
775 split->block_start = em->block_start;
778 split->block_len = em->block_len;
780 split->block_len = split->len;
781 split->orig_block_len = max(split->block_len,
783 split->ram_bytes = em->ram_bytes;
785 split->orig_start = split->start;
786 split->block_len = 0;
787 split->block_start = em->block_start;
788 split->orig_block_len = 0;
789 split->ram_bytes = split->len;
792 split->generation = gen;
793 split->flags = flags;
794 replace_extent_mapping(em_tree, em, split, modified);
795 free_extent_map(split);
807 split->len = em_end - end;
808 split->block_start = em->block_start;
809 split->flags = flags;
810 split->generation = gen;
812 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
813 split->orig_block_len = max(em->block_len,
816 split->ram_bytes = em->ram_bytes;
818 split->block_len = em->block_len;
819 split->orig_start = em->orig_start;
821 const u64 diff = end - em->start;
823 split->block_len = split->len;
824 split->block_start += diff;
825 split->orig_start = em->orig_start;
828 split->ram_bytes = split->len;
829 split->orig_start = split->start;
830 split->block_len = 0;
831 split->orig_block_len = 0;
834 if (extent_map_in_tree(em)) {
835 replace_extent_mapping(em_tree, em, split,
840 ret = add_extent_mapping(em_tree, split,
842 /* Logic error, shouldn't happen. */
844 if (WARN_ON(ret != 0) && modified)
845 btrfs_set_inode_full_sync(inode);
847 free_extent_map(split);
851 if (extent_map_in_tree(em)) {
853 * If the extent map is still in the tree it means that
854 * either of the following is true:
856 * 1) It fits entirely in our range (doesn't end beyond
857 * it or starts before it);
859 * 2) It starts before our range and/or ends after our
860 * range, and we were not able to allocate the extent
861 * maps for split operations, @split and @split2.
863 * If we are at case 2) then we just remove the entire
864 * extent map - this is fine since if anyone needs it to
865 * access the subranges outside our range, will just
866 * load it again from the subvolume tree's file extent
867 * item. However if the extent map was in the list of
868 * modified extents, then we must mark the inode for a
869 * full fsync, otherwise a fast fsync will miss this
870 * extent if it's new and needs to be logged.
872 if ((em->start < start || em_end > end) && modified) {
874 btrfs_set_inode_full_sync(inode);
876 remove_extent_mapping(em_tree, em);
880 * Once for the tree reference (we replaced or removed the
881 * extent map from the tree).
885 /* Once for us (for our lookup reference). */
891 write_unlock(&em_tree->lock);
893 free_extent_map(split);
894 free_extent_map(split2);
898 * Replace a range in the inode's extent map tree with a new extent map.
900 * @inode: The target inode.
901 * @new_em: The new extent map to add to the inode's extent map tree.
902 * @modified: Indicate if the new extent map should be added to the list of
903 * modified extents (for fast fsync tracking).
905 * Drops all the extent maps in the inode's extent map tree that intersect the
906 * range of the new extent map and adds the new extent map to the tree.
907 * The caller should have locked an appropriate file range in the inode's io
908 * tree before calling this function.
910 int btrfs_replace_extent_map_range(struct btrfs_inode *inode,
911 struct extent_map *new_em,
914 const u64 end = new_em->start + new_em->len - 1;
915 struct extent_map_tree *tree = &inode->extent_tree;
918 ASSERT(!extent_map_in_tree(new_em));
921 * The caller has locked an appropriate file range in the inode's io
922 * tree, but getting -EEXIST when adding the new extent map can still
923 * happen in case there are extents that partially cover the range, and
924 * this is due to two tasks operating on different parts of the extent.
925 * See commit 18e83ac75bfe67 ("Btrfs: fix unexpected EEXIST from
926 * btrfs_get_extent") for an example and details.
929 btrfs_drop_extent_map_range(inode, new_em->start, end, false);
930 write_lock(&tree->lock);
931 ret = add_extent_mapping(tree, new_em, modified);
932 write_unlock(&tree->lock);
933 } while (ret == -EEXIST);
939 * Split off the first pre bytes from the extent_map at [start, start + len],
940 * and set the block_start for it to new_logical.
942 * This function is used when an ordered_extent needs to be split.
944 int split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre,
947 struct extent_map_tree *em_tree = &inode->extent_tree;
948 struct extent_map *em;
949 struct extent_map *split_pre = NULL;
950 struct extent_map *split_mid = NULL;
957 split_pre = alloc_extent_map();
960 split_mid = alloc_extent_map();
966 lock_extent(&inode->io_tree, start, start + len - 1, NULL);
967 write_lock(&em_tree->lock);
968 em = lookup_extent_mapping(em_tree, start, len);
974 ASSERT(em->len == len);
975 ASSERT(!extent_map_is_compressed(em));
976 ASSERT(em->block_start < EXTENT_MAP_LAST_BYTE);
977 ASSERT(em->flags & EXTENT_FLAG_PINNED);
978 ASSERT(!(em->flags & EXTENT_FLAG_LOGGING));
979 ASSERT(!list_empty(&em->list));
982 em->flags &= ~EXTENT_FLAG_PINNED;
984 /* First, replace the em with a new extent_map starting from * em->start */
985 split_pre->start = em->start;
986 split_pre->len = pre;
987 split_pre->orig_start = split_pre->start;
988 split_pre->block_start = new_logical;
989 split_pre->block_len = split_pre->len;
990 split_pre->orig_block_len = split_pre->block_len;
991 split_pre->ram_bytes = split_pre->len;
992 split_pre->flags = flags;
993 split_pre->generation = em->generation;
995 replace_extent_mapping(em_tree, em, split_pre, 1);
998 * Now we only have an extent_map at:
999 * [em->start, em->start + pre]
1002 /* Insert the middle extent_map. */
1003 split_mid->start = em->start + pre;
1004 split_mid->len = em->len - pre;
1005 split_mid->orig_start = split_mid->start;
1006 split_mid->block_start = em->block_start + pre;
1007 split_mid->block_len = split_mid->len;
1008 split_mid->orig_block_len = split_mid->block_len;
1009 split_mid->ram_bytes = split_mid->len;
1010 split_mid->flags = flags;
1011 split_mid->generation = em->generation;
1012 add_extent_mapping(em_tree, split_mid, 1);
1015 free_extent_map(em);
1016 /* Once for the tree */
1017 free_extent_map(em);
1020 write_unlock(&em_tree->lock);
1021 unlock_extent(&inode->io_tree, start, start + len - 1, NULL);
1022 free_extent_map(split_mid);
1024 free_extent_map(split_pre);