1 // SPDX-License-Identifier: GPL-2.0
4 #include <linux/slab.h>
5 #include <linux/spinlock.h>
8 #include "extent_map.h"
9 #include "compression.h"
10 #include "btrfs_inode.h"
13 static struct kmem_cache *extent_map_cache;
15 int __init extent_map_init(void)
17 extent_map_cache = kmem_cache_create("btrfs_extent_map",
18 sizeof(struct extent_map), 0, 0, NULL);
19 if (!extent_map_cache)
24 void __cold extent_map_exit(void)
26 kmem_cache_destroy(extent_map_cache);
30 * Initialize the extent tree @tree. Should be called for each new inode or
31 * other user of the extent_map interface.
33 void extent_map_tree_init(struct extent_map_tree *tree)
35 tree->map = RB_ROOT_CACHED;
36 INIT_LIST_HEAD(&tree->modified_extents);
37 rwlock_init(&tree->lock);
41 * Allocate a new extent_map structure. The new structure is returned with a
42 * reference count of one and needs to be freed using free_extent_map()
44 struct extent_map *alloc_extent_map(void)
46 struct extent_map *em;
47 em = kmem_cache_zalloc(extent_map_cache, GFP_NOFS);
50 RB_CLEAR_NODE(&em->rb_node);
51 refcount_set(&em->refs, 1);
52 INIT_LIST_HEAD(&em->list);
57 * Drop the reference out on @em by one and free the structure if the reference
60 void free_extent_map(struct extent_map *em)
64 if (refcount_dec_and_test(&em->refs)) {
65 WARN_ON(extent_map_in_tree(em));
66 WARN_ON(!list_empty(&em->list));
67 kmem_cache_free(extent_map_cache, em);
71 /* Do the math around the end of an extent, handling wrapping. */
72 static u64 range_end(u64 start, u64 len)
74 if (start + len < start)
79 static int tree_insert(struct rb_root_cached *root, struct extent_map *em)
81 struct rb_node **p = &root->rb_root.rb_node;
82 struct rb_node *parent = NULL;
83 struct extent_map *entry = NULL;
84 struct rb_node *orig_parent = NULL;
85 u64 end = range_end(em->start, em->len);
90 entry = rb_entry(parent, struct extent_map, rb_node);
92 if (em->start < entry->start) {
94 } else if (em->start >= extent_map_end(entry)) {
102 orig_parent = parent;
103 while (parent && em->start >= extent_map_end(entry)) {
104 parent = rb_next(parent);
105 entry = rb_entry(parent, struct extent_map, rb_node);
108 if (end > entry->start && em->start < extent_map_end(entry))
111 parent = orig_parent;
112 entry = rb_entry(parent, struct extent_map, rb_node);
113 while (parent && em->start < entry->start) {
114 parent = rb_prev(parent);
115 entry = rb_entry(parent, struct extent_map, rb_node);
118 if (end > entry->start && em->start < extent_map_end(entry))
121 rb_link_node(&em->rb_node, orig_parent, p);
122 rb_insert_color_cached(&em->rb_node, root, leftmost);
127 * Search through the tree for an extent_map with a given offset. If it can't
128 * be found, try to find some neighboring extents
130 static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
131 struct rb_node **prev_or_next_ret)
133 struct rb_node *n = root->rb_node;
134 struct rb_node *prev = NULL;
135 struct rb_node *orig_prev = NULL;
136 struct extent_map *entry;
137 struct extent_map *prev_entry = NULL;
139 ASSERT(prev_or_next_ret);
142 entry = rb_entry(n, struct extent_map, rb_node);
146 if (offset < entry->start)
148 else if (offset >= extent_map_end(entry))
155 while (prev && offset >= extent_map_end(prev_entry)) {
156 prev = rb_next(prev);
157 prev_entry = rb_entry(prev, struct extent_map, rb_node);
161 * Previous extent map found, return as in this case the caller does not
162 * care about the next one.
165 *prev_or_next_ret = prev;
170 prev_entry = rb_entry(prev, struct extent_map, rb_node);
171 while (prev && offset < prev_entry->start) {
172 prev = rb_prev(prev);
173 prev_entry = rb_entry(prev, struct extent_map, rb_node);
175 *prev_or_next_ret = prev;
180 static inline u64 extent_map_block_end(const struct extent_map *em)
182 if (em->block_start + em->block_len < em->block_start)
184 return em->block_start + em->block_len;
187 static bool can_merge_extent_map(const struct extent_map *em)
189 if (em->flags & EXTENT_FLAG_PINNED)
192 /* Don't merge compressed extents, we need to know their actual size. */
193 if (extent_map_is_compressed(em))
196 if (em->flags & EXTENT_FLAG_LOGGING)
200 * We don't want to merge stuff that hasn't been written to the log yet
201 * since it may not reflect exactly what is on disk, and that would be
204 if (!list_empty(&em->list))
210 /* Check to see if two extent_map structs are adjacent and safe to merge. */
211 static bool mergeable_maps(const struct extent_map *prev, const struct extent_map *next)
213 if (extent_map_end(prev) != next->start)
216 if (prev->flags != next->flags)
219 if (next->block_start < EXTENT_MAP_LAST_BYTE - 1)
220 return next->block_start == extent_map_block_end(prev);
222 /* HOLES and INLINE extents. */
223 return next->block_start == prev->block_start;
226 static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
228 struct extent_map *merge = NULL;
232 * We can't modify an extent map that is in the tree and that is being
233 * used by another task, as it can cause that other task to see it in
234 * inconsistent state during the merging. We always have 1 reference for
235 * the tree and 1 for this task (which is unpinning the extent map or
236 * clearing the logging flag), so anything > 2 means it's being used by
239 if (refcount_read(&em->refs) > 2)
242 if (!can_merge_extent_map(em))
245 if (em->start != 0) {
246 rb = rb_prev(&em->rb_node);
248 merge = rb_entry(rb, struct extent_map, rb_node);
249 if (rb && can_merge_extent_map(merge) && mergeable_maps(merge, em)) {
250 em->start = merge->start;
251 em->orig_start = merge->orig_start;
252 em->len += merge->len;
253 em->block_len += merge->block_len;
254 em->block_start = merge->block_start;
255 em->mod_len = (em->mod_len + em->mod_start) - merge->mod_start;
256 em->mod_start = merge->mod_start;
257 em->generation = max(em->generation, merge->generation);
258 em->flags |= EXTENT_FLAG_MERGED;
260 rb_erase_cached(&merge->rb_node, &tree->map);
261 RB_CLEAR_NODE(&merge->rb_node);
262 free_extent_map(merge);
266 rb = rb_next(&em->rb_node);
268 merge = rb_entry(rb, struct extent_map, rb_node);
269 if (rb && can_merge_extent_map(merge) && mergeable_maps(em, merge)) {
270 em->len += merge->len;
271 em->block_len += merge->block_len;
272 rb_erase_cached(&merge->rb_node, &tree->map);
273 RB_CLEAR_NODE(&merge->rb_node);
274 em->mod_len = (merge->mod_start + merge->mod_len) - em->mod_start;
275 em->generation = max(em->generation, merge->generation);
276 em->flags |= EXTENT_FLAG_MERGED;
277 free_extent_map(merge);
282 * Unpin an extent from the cache.
284 * @inode: the inode from which we are unpinning an extent range
285 * @start: logical offset in the file
286 * @len: length of the extent
287 * @gen: generation that this extent has been modified in
289 * Called after an extent has been written to disk properly. Set the generation
290 * to the generation that actually added the file item to the inode so we know
291 * we need to sync this extent when we call fsync().
293 * Returns: 0 on success
294 * -ENOENT when the extent is not found in the tree
295 * -EUCLEAN if the found extent does not match the expected start
297 int unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len, u64 gen)
299 struct btrfs_fs_info *fs_info = inode->root->fs_info;
300 struct extent_map_tree *tree = &inode->extent_tree;
302 struct extent_map *em;
303 bool prealloc = false;
305 write_lock(&tree->lock);
306 em = lookup_extent_mapping(tree, start, len);
310 "no extent map found for inode %llu (root %lld) when unpinning extent range [%llu, %llu), generation %llu",
311 btrfs_ino(inode), btrfs_root_id(inode->root),
317 if (WARN_ON(em->start != start)) {
319 "found extent map for inode %llu (root %lld) with unexpected start offset %llu when unpinning extent range [%llu, %llu), generation %llu",
320 btrfs_ino(inode), btrfs_root_id(inode->root),
321 em->start, start, len, gen);
326 em->generation = gen;
327 em->flags &= ~EXTENT_FLAG_PINNED;
328 em->mod_start = em->start;
329 em->mod_len = em->len;
331 if (em->flags & EXTENT_FLAG_FILLING) {
333 em->flags &= ~EXTENT_FLAG_FILLING;
336 try_merge_map(tree, em);
339 em->mod_start = em->start;
340 em->mod_len = em->len;
345 write_unlock(&tree->lock);
350 void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em)
352 lockdep_assert_held_write(&tree->lock);
354 em->flags &= ~EXTENT_FLAG_LOGGING;
355 if (extent_map_in_tree(em))
356 try_merge_map(tree, em);
359 static inline void setup_extent_mapping(struct extent_map_tree *tree,
360 struct extent_map *em,
363 refcount_inc(&em->refs);
364 em->mod_start = em->start;
365 em->mod_len = em->len;
367 ASSERT(list_empty(&em->list));
370 list_add(&em->list, &tree->modified_extents);
372 try_merge_map(tree, em);
376 * Add new extent map to the extent tree
378 * @tree: tree to insert new map in
380 * @modified: indicate whether the given @em should be added to the
381 * modified list, which indicates the extent needs to be logged
383 * Insert @em into @tree or perform a simple forward/backward merge with
384 * existing mappings. The extent_map struct passed in will be inserted
385 * into the tree directly, with an additional reference taken, or a
386 * reference dropped if the merge attempt was successful.
388 static int add_extent_mapping(struct extent_map_tree *tree,
389 struct extent_map *em, int modified)
393 lockdep_assert_held_write(&tree->lock);
395 ret = tree_insert(&tree->map, em);
399 setup_extent_mapping(tree, em, modified);
404 static struct extent_map *
405 __lookup_extent_mapping(struct extent_map_tree *tree,
406 u64 start, u64 len, int strict)
408 struct extent_map *em;
409 struct rb_node *rb_node;
410 struct rb_node *prev_or_next = NULL;
411 u64 end = range_end(start, len);
413 rb_node = __tree_search(&tree->map.rb_root, start, &prev_or_next);
416 rb_node = prev_or_next;
421 em = rb_entry(rb_node, struct extent_map, rb_node);
423 if (strict && !(end > em->start && start < extent_map_end(em)))
426 refcount_inc(&em->refs);
431 * Lookup extent_map that intersects @start + @len range.
433 * @tree: tree to lookup in
434 * @start: byte offset to start the search
435 * @len: length of the lookup range
437 * Find and return the first extent_map struct in @tree that intersects the
438 * [start, len] range. There may be additional objects in the tree that
439 * intersect, so check the object returned carefully to make sure that no
440 * additional lookups are needed.
442 struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
445 return __lookup_extent_mapping(tree, start, len, 1);
449 * Find a nearby extent map intersecting @start + @len (not an exact search).
451 * @tree: tree to lookup in
452 * @start: byte offset to start the search
453 * @len: length of the lookup range
455 * Find and return the first extent_map struct in @tree that intersects the
456 * [start, len] range.
458 * If one can't be found, any nearby extent may be returned
460 struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
463 return __lookup_extent_mapping(tree, start, len, 0);
467 * Remove an extent_map from the extent tree.
469 * @tree: extent tree to remove from
470 * @em: extent map being removed
472 * Remove @em from @tree. No reference counts are dropped, and no checks
473 * are done to see if the range is in use.
475 void remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
477 lockdep_assert_held_write(&tree->lock);
479 WARN_ON(em->flags & EXTENT_FLAG_PINNED);
480 rb_erase_cached(&em->rb_node, &tree->map);
481 if (!(em->flags & EXTENT_FLAG_LOGGING))
482 list_del_init(&em->list);
483 RB_CLEAR_NODE(&em->rb_node);
486 static void replace_extent_mapping(struct extent_map_tree *tree,
487 struct extent_map *cur,
488 struct extent_map *new,
491 lockdep_assert_held_write(&tree->lock);
493 WARN_ON(cur->flags & EXTENT_FLAG_PINNED);
494 ASSERT(extent_map_in_tree(cur));
495 if (!(cur->flags & EXTENT_FLAG_LOGGING))
496 list_del_init(&cur->list);
497 rb_replace_node_cached(&cur->rb_node, &new->rb_node, &tree->map);
498 RB_CLEAR_NODE(&cur->rb_node);
500 setup_extent_mapping(tree, new, modified);
503 static struct extent_map *next_extent_map(const struct extent_map *em)
505 struct rb_node *next;
507 next = rb_next(&em->rb_node);
510 return container_of(next, struct extent_map, rb_node);
513 static struct extent_map *prev_extent_map(struct extent_map *em)
515 struct rb_node *prev;
517 prev = rb_prev(&em->rb_node);
520 return container_of(prev, struct extent_map, rb_node);
524 * Helper for btrfs_get_extent. Given an existing extent in the tree,
525 * the existing extent is the nearest extent to map_start,
526 * and an extent that you want to insert, deal with overlap and insert
527 * the best fitted new extent into the tree.
529 static noinline int merge_extent_mapping(struct extent_map_tree *em_tree,
530 struct extent_map *existing,
531 struct extent_map *em,
534 struct extent_map *prev;
535 struct extent_map *next;
540 if (map_start < em->start || map_start >= extent_map_end(em))
543 if (existing->start > map_start) {
545 prev = prev_extent_map(next);
548 next = next_extent_map(prev);
551 start = prev ? extent_map_end(prev) : em->start;
552 start = max_t(u64, start, em->start);
553 end = next ? next->start : extent_map_end(em);
554 end = min_t(u64, end, extent_map_end(em));
555 start_diff = start - em->start;
557 em->len = end - start;
558 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
559 !extent_map_is_compressed(em)) {
560 em->block_start += start_diff;
561 em->block_len = em->len;
563 return add_extent_mapping(em_tree, em, 0);
567 * Add extent mapping into em_tree.
569 * @fs_info: the filesystem
570 * @em_tree: extent tree into which we want to insert the extent mapping
571 * @em_in: extent we are inserting
572 * @start: start of the logical range btrfs_get_extent() is requesting
573 * @len: length of the logical range btrfs_get_extent() is requesting
575 * Note that @em_in's range may be different from [start, start+len),
576 * but they must be overlapped.
578 * Insert @em_in into @em_tree. In case there is an overlapping range, handle
579 * the -EEXIST by either:
580 * a) Returning the existing extent in @em_in if @start is within the
582 * b) Merge the existing extent with @em_in passed in.
584 * Return 0 on success, otherwise -EEXIST.
587 int btrfs_add_extent_mapping(struct btrfs_fs_info *fs_info,
588 struct extent_map_tree *em_tree,
589 struct extent_map **em_in, u64 start, u64 len)
592 struct extent_map *em = *em_in;
595 * Tree-checker should have rejected any inline extent with non-zero
596 * file offset. Here just do a sanity check.
598 if (em->block_start == EXTENT_MAP_INLINE)
599 ASSERT(em->start == 0);
601 ret = add_extent_mapping(em_tree, em, 0);
602 /* it is possible that someone inserted the extent into the tree
603 * while we had the lock dropped. It is also possible that
604 * an overlapping map exists in the tree
606 if (ret == -EEXIST) {
607 struct extent_map *existing;
609 existing = search_extent_mapping(em_tree, start, len);
611 trace_btrfs_handle_em_exist(fs_info, existing, em, start, len);
614 * existing will always be non-NULL, since there must be
615 * extent causing the -EEXIST.
617 if (start >= existing->start &&
618 start < extent_map_end(existing)) {
623 u64 orig_start = em->start;
624 u64 orig_len = em->len;
627 * The existing extent map is the one nearest to
628 * the [start, start + len) range which overlaps
630 ret = merge_extent_mapping(em_tree, existing,
636 "extent map merge error existing [%llu, %llu) with em [%llu, %llu) start %llu\n",
637 existing->start, existing->len,
638 orig_start, orig_len, start);
640 free_extent_map(existing);
644 ASSERT(ret == 0 || ret == -EEXIST);
649 * Drop all extent maps from a tree in the fastest possible way, rescheduling
650 * if needed. This avoids searching the tree, from the root down to the first
651 * extent map, before each deletion.
653 static void drop_all_extent_maps_fast(struct extent_map_tree *tree)
655 write_lock(&tree->lock);
656 while (!RB_EMPTY_ROOT(&tree->map.rb_root)) {
657 struct extent_map *em;
658 struct rb_node *node;
660 node = rb_first_cached(&tree->map);
661 em = rb_entry(node, struct extent_map, rb_node);
662 em->flags &= ~(EXTENT_FLAG_PINNED | EXTENT_FLAG_LOGGING);
663 remove_extent_mapping(tree, em);
665 cond_resched_rwlock_write(&tree->lock);
667 write_unlock(&tree->lock);
671 * Drop all extent maps in a given range.
673 * @inode: The target inode.
674 * @start: Start offset of the range.
675 * @end: End offset of the range (inclusive value).
676 * @skip_pinned: Indicate if pinned extent maps should be ignored or not.
678 * This drops all the extent maps that intersect the given range [@start, @end].
679 * Extent maps that partially overlap the range and extend behind or beyond it,
681 * The caller should have locked an appropriate file range in the inode's io
682 * tree before calling this function.
684 void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end,
687 struct extent_map *split;
688 struct extent_map *split2;
689 struct extent_map *em;
690 struct extent_map_tree *em_tree = &inode->extent_tree;
691 u64 len = end - start + 1;
693 WARN_ON(end < start);
694 if (end == (u64)-1) {
695 if (start == 0 && !skip_pinned) {
696 drop_all_extent_maps_fast(em_tree);
701 /* Make end offset exclusive for use in the loop below. */
706 * It's ok if we fail to allocate the extent maps, see the comment near
707 * the bottom of the loop below. We only need two spare extent maps in
708 * the worst case, where the first extent map that intersects our range
709 * starts before the range and the last extent map that intersects our
710 * range ends after our range (and they might be the same extent map),
711 * because we need to split those two extent maps at the boundaries.
713 split = alloc_extent_map();
714 split2 = alloc_extent_map();
716 write_lock(&em_tree->lock);
717 em = lookup_extent_mapping(em_tree, start, len);
720 /* extent_map_end() returns exclusive value (last byte + 1). */
721 const u64 em_end = extent_map_end(em);
722 struct extent_map *next_em = NULL;
729 next_em = next_extent_map(em);
731 if (next_em->start < end)
732 refcount_inc(&next_em->refs);
738 if (skip_pinned && (em->flags & EXTENT_FLAG_PINNED)) {
745 * In case we split the extent map, we want to preserve the
746 * EXTENT_FLAG_LOGGING flag on our extent map, but we don't want
747 * it on the new extent maps.
749 em->flags &= ~(EXTENT_FLAG_PINNED | EXTENT_FLAG_LOGGING);
750 modified = !list_empty(&em->list);
753 * The extent map does not cross our target range, so no need to
754 * split it, we can remove it directly.
756 if (em->start >= start && em_end <= end)
759 gen = em->generation;
760 compressed = extent_map_is_compressed(em);
762 if (em->start < start) {
769 split->start = em->start;
770 split->len = start - em->start;
772 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
773 split->orig_start = em->orig_start;
774 split->block_start = em->block_start;
777 split->block_len = em->block_len;
779 split->block_len = split->len;
780 split->orig_block_len = max(split->block_len,
782 split->ram_bytes = em->ram_bytes;
784 split->orig_start = split->start;
785 split->block_len = 0;
786 split->block_start = em->block_start;
787 split->orig_block_len = 0;
788 split->ram_bytes = split->len;
791 split->generation = gen;
792 split->flags = flags;
793 replace_extent_mapping(em_tree, em, split, modified);
794 free_extent_map(split);
806 split->len = em_end - end;
807 split->block_start = em->block_start;
808 split->flags = flags;
809 split->generation = gen;
811 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
812 split->orig_block_len = max(em->block_len,
815 split->ram_bytes = em->ram_bytes;
817 split->block_len = em->block_len;
818 split->orig_start = em->orig_start;
820 const u64 diff = start + len - em->start;
822 split->block_len = split->len;
823 split->block_start += diff;
824 split->orig_start = em->orig_start;
827 split->ram_bytes = split->len;
828 split->orig_start = split->start;
829 split->block_len = 0;
830 split->orig_block_len = 0;
833 if (extent_map_in_tree(em)) {
834 replace_extent_mapping(em_tree, em, split,
839 ret = add_extent_mapping(em_tree, split,
841 /* Logic error, shouldn't happen. */
843 if (WARN_ON(ret != 0) && modified)
844 btrfs_set_inode_full_sync(inode);
846 free_extent_map(split);
850 if (extent_map_in_tree(em)) {
852 * If the extent map is still in the tree it means that
853 * either of the following is true:
855 * 1) It fits entirely in our range (doesn't end beyond
856 * it or starts before it);
858 * 2) It starts before our range and/or ends after our
859 * range, and we were not able to allocate the extent
860 * maps for split operations, @split and @split2.
862 * If we are at case 2) then we just remove the entire
863 * extent map - this is fine since if anyone needs it to
864 * access the subranges outside our range, will just
865 * load it again from the subvolume tree's file extent
866 * item. However if the extent map was in the list of
867 * modified extents, then we must mark the inode for a
868 * full fsync, otherwise a fast fsync will miss this
869 * extent if it's new and needs to be logged.
871 if ((em->start < start || em_end > end) && modified) {
873 btrfs_set_inode_full_sync(inode);
875 remove_extent_mapping(em_tree, em);
879 * Once for the tree reference (we replaced or removed the
880 * extent map from the tree).
884 /* Once for us (for our lookup reference). */
890 write_unlock(&em_tree->lock);
892 free_extent_map(split);
893 free_extent_map(split2);
897 * Replace a range in the inode's extent map tree with a new extent map.
899 * @inode: The target inode.
900 * @new_em: The new extent map to add to the inode's extent map tree.
901 * @modified: Indicate if the new extent map should be added to the list of
902 * modified extents (for fast fsync tracking).
904 * Drops all the extent maps in the inode's extent map tree that intersect the
905 * range of the new extent map and adds the new extent map to the tree.
906 * The caller should have locked an appropriate file range in the inode's io
907 * tree before calling this function.
909 int btrfs_replace_extent_map_range(struct btrfs_inode *inode,
910 struct extent_map *new_em,
913 const u64 end = new_em->start + new_em->len - 1;
914 struct extent_map_tree *tree = &inode->extent_tree;
917 ASSERT(!extent_map_in_tree(new_em));
920 * The caller has locked an appropriate file range in the inode's io
921 * tree, but getting -EEXIST when adding the new extent map can still
922 * happen in case there are extents that partially cover the range, and
923 * this is due to two tasks operating on different parts of the extent.
924 * See commit 18e83ac75bfe67 ("Btrfs: fix unexpected EEXIST from
925 * btrfs_get_extent") for an example and details.
928 btrfs_drop_extent_map_range(inode, new_em->start, end, false);
929 write_lock(&tree->lock);
930 ret = add_extent_mapping(tree, new_em, modified);
931 write_unlock(&tree->lock);
932 } while (ret == -EEXIST);
938 * Split off the first pre bytes from the extent_map at [start, start + len],
939 * and set the block_start for it to new_logical.
941 * This function is used when an ordered_extent needs to be split.
943 int split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre,
946 struct extent_map_tree *em_tree = &inode->extent_tree;
947 struct extent_map *em;
948 struct extent_map *split_pre = NULL;
949 struct extent_map *split_mid = NULL;
956 split_pre = alloc_extent_map();
959 split_mid = alloc_extent_map();
965 lock_extent(&inode->io_tree, start, start + len - 1, NULL);
966 write_lock(&em_tree->lock);
967 em = lookup_extent_mapping(em_tree, start, len);
973 ASSERT(em->len == len);
974 ASSERT(!extent_map_is_compressed(em));
975 ASSERT(em->block_start < EXTENT_MAP_LAST_BYTE);
976 ASSERT(em->flags & EXTENT_FLAG_PINNED);
977 ASSERT(!(em->flags & EXTENT_FLAG_LOGGING));
978 ASSERT(!list_empty(&em->list));
981 em->flags &= ~EXTENT_FLAG_PINNED;
983 /* First, replace the em with a new extent_map starting from * em->start */
984 split_pre->start = em->start;
985 split_pre->len = pre;
986 split_pre->orig_start = split_pre->start;
987 split_pre->block_start = new_logical;
988 split_pre->block_len = split_pre->len;
989 split_pre->orig_block_len = split_pre->block_len;
990 split_pre->ram_bytes = split_pre->len;
991 split_pre->flags = flags;
992 split_pre->generation = em->generation;
994 replace_extent_mapping(em_tree, em, split_pre, 1);
997 * Now we only have an extent_map at:
998 * [em->start, em->start + pre]
1001 /* Insert the middle extent_map. */
1002 split_mid->start = em->start + pre;
1003 split_mid->len = em->len - pre;
1004 split_mid->orig_start = split_mid->start;
1005 split_mid->block_start = em->block_start + pre;
1006 split_mid->block_len = split_mid->len;
1007 split_mid->orig_block_len = split_mid->block_len;
1008 split_mid->ram_bytes = split_mid->len;
1009 split_mid->flags = flags;
1010 split_mid->generation = em->generation;
1011 add_extent_mapping(em_tree, split_mid, 1);
1014 free_extent_map(em);
1015 /* Once for the tree */
1016 free_extent_map(em);
1019 write_unlock(&em_tree->lock);
1020 unlock_extent(&inode->io_tree, start, start + len - 1, NULL);
1021 free_extent_map(split_mid);
1023 free_extent_map(split_pre);