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Btrfs: clean up code for extent_map lookup 

lookup_extent_map() and search_extent_map() can share most of code.

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 03:18:15 +00:00 committed by Chris Mason
parent 7e016a038e
commit ed64f06652
1 changed files with 30 additions and 57 deletions
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87
fs/btrfs/extent_map.c
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@ -299,6 +299,34 @@ static u64 range_end(u64 start, u64 len)
return start + len;
}
struct extent_map *__lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 len, int strict)
{
struct extent_map *em;
struct rb_node *rb_node;
struct rb_node *prev = NULL;
struct rb_node *next = NULL;
u64 end = range_end(start, len);
rb_node = __tree_search(&tree->map, start, &prev, &next);
if (!rb_node) {
if (prev)
rb_node = prev;
else if (next)
rb_node = next;
else
return NULL;
}
em = rb_entry(rb_node, struct extent_map, rb_node);
if (strict && !(end > em->start && start < extent_map_end(em)))
return NULL;
atomic_inc(&em->refs);
return em;
}
/**
* lookup_extent_mapping - lookup extent_map
* @tree: tree to lookup in
@ -313,42 +341,7 @@ static u64 range_end(u64 start, u64 len)
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 len)
{
struct extent_map *em;
struct rb_node *rb_node;
struct rb_node *prev = NULL;
struct rb_node *next = NULL;
u64 end = range_end(start, len);
rb_node = __tree_search(&tree->map, start, &prev, &next);
if (!rb_node && prev) {
em = rb_entry(prev, struct extent_map, rb_node);
if (end > em->start && start < extent_map_end(em))
goto found;
}
if (!rb_node && next) {
em = rb_entry(next, struct extent_map, rb_node);
if (end > em->start && start < extent_map_end(em))
goto found;
}
if (!rb_node) {
em = NULL;
goto out;
}
if (IS_ERR(rb_node)) {
em = ERR_CAST(rb_node);
goto out;
}
em = rb_entry(rb_node, struct extent_map, rb_node);
if (end > em->start && start < extent_map_end(em))
goto found;
em = NULL;
goto out;
found:
atomic_inc(&em->refs);
out:
return em;
return __lookup_extent_mapping(tree, start, len, 1);
}
/**
@ -365,27 +358,7 @@ out:
struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 len)
{
struct extent_map *em;
struct rb_node *rb_node;
struct rb_node *prev = NULL;
struct rb_node *next = NULL;
rb_node = __tree_search(&tree->map, start, &prev, &next);
if (!rb_node && prev) {
em = rb_entry(prev, struct extent_map, rb_node);
goto found;
}
if (!rb_node && next) {
em = rb_entry(next, struct extent_map, rb_node);
goto found;
}
if (!rb_node)
return NULL;
em = rb_entry(rb_node, struct extent_map, rb_node);
found:
atomic_inc(&em->refs);
return em;
return __lookup_extent_mapping(tree, start, len, 0);
}
/**