Commit ed64f066 authored by Li Zefan's avatar Li Zefan Committed by Chris Mason

Btrfs: clean up code for extent_map lookup

lookup_extent_map() and search_extent_map() can share most of code.
Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 7e016a03
......@@ -299,19 +299,8 @@ static u64 range_end(u64 start, u64 len)
return start + len;
}
/**
* lookup_extent_mapping - lookup extent_map
* @tree: tree to lookup in
* @start: byte offset to start the search
* @len: length of the lookup range
*
* Find and return the first extent_map struct in @tree that intersects the
* [start, len] range. There may be additional objects in the tree that
* intersect, so check the object returned carefully to make sure that no
* additional lookups are needed.
*/
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 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;
......@@ -320,37 +309,41 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
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;
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 (end > em->start && start < extent_map_end(em))
goto found;
em = NULL;
goto out;
if (strict && !(end > em->start && start < extent_map_end(em)))
return NULL;
found:
atomic_inc(&em->refs);
out:
return em;
}
/**
* lookup_extent_mapping - lookup extent_map
* @tree: tree to lookup in
* @start: byte offset to start the search
* @len: length of the lookup range
*
* Find and return the first extent_map struct in @tree that intersects the
* [start, len] range. There may be additional objects in the tree that
* intersect, so check the object returned carefully to make sure that no
* additional lookups are needed.
*/
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 len)
{
return __lookup_extent_mapping(tree, start, len, 1);
}
/**
* search_extent_mapping - find a nearby extent map
* @tree: tree to lookup in
......@@ -365,27 +358,7 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
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);
}
/**
......
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