Btrfs: clean up code for merging extent maps
unpin_extent_cache() and add_extent_mapping() shares the same code
that merges extent maps.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index df7a803..7c97b33 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -183,22 +183,10 @@
return 0;
}
-int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len)
+static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
{
- int ret = 0;
struct extent_map *merge = NULL;
struct rb_node *rb;
- struct extent_map *em;
-
- write_lock(&tree->lock);
- em = lookup_extent_mapping(tree, start, len);
-
- WARN_ON(!em || em->start != start);
-
- if (!em)
- goto out;
-
- clear_bit(EXTENT_FLAG_PINNED, &em->flags);
if (em->start != 0) {
rb = rb_prev(&em->rb_node);
@@ -225,6 +213,24 @@
merge->in_tree = 0;
free_extent_map(merge);
}
+}
+
+int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len)
+{
+ int ret = 0;
+ struct extent_map *em;
+
+ write_lock(&tree->lock);
+ em = lookup_extent_mapping(tree, start, len);
+
+ WARN_ON(!em || em->start != start);
+
+ if (!em)
+ goto out;
+
+ clear_bit(EXTENT_FLAG_PINNED, &em->flags);
+
+ try_merge_map(tree, em);
free_extent_map(em);
out:
@@ -247,7 +253,6 @@
struct extent_map *em)
{
int ret = 0;
- struct extent_map *merge = NULL;
struct rb_node *rb;
struct extent_map *exist;
@@ -263,30 +268,8 @@
goto out;
}
atomic_inc(&em->refs);
- if (em->start != 0) {
- rb = rb_prev(&em->rb_node);
- if (rb)
- merge = rb_entry(rb, struct extent_map, rb_node);
- if (rb && mergable_maps(merge, em)) {
- em->start = merge->start;
- em->len += merge->len;
- em->block_len += merge->block_len;
- em->block_start = merge->block_start;
- merge->in_tree = 0;
- rb_erase(&merge->rb_node, &tree->map);
- free_extent_map(merge);
- }
- }
- rb = rb_next(&em->rb_node);
- if (rb)
- merge = rb_entry(rb, struct extent_map, rb_node);
- if (rb && mergable_maps(em, merge)) {
- em->len += merge->len;
- em->block_len += merge->len;
- rb_erase(&merge->rb_node, &tree->map);
- merge->in_tree = 0;
- free_extent_map(merge);
- }
+
+ try_merge_map(tree, em);
out:
return ret;
}