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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>
This commit is contained in:
Li Zefan 2011-07-14 03:18:33 +00:00 committed by Chris Mason
parent ed64f06652
commit 4d2c8f62f1
1 changed files with 21 additions and 38 deletions
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59
fs/btrfs/extent_map.c
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@ -183,22 +183,10 @@ static int mergable_maps(struct extent_map *prev, struct extent_map *next)
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 @@ int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len)
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 @@ int add_extent_mapping(struct extent_map_tree *tree,
struct extent_map *em)
{
int ret = 0;
struct extent_map *merge = NULL;
struct rb_node *rb;
struct extent_map *exist;
@ -263,30 +268,8 @@ int add_extent_mapping(struct extent_map_tree *tree,
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;
}