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

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

fs/btrfs/extent_map.c

+29 −56
Original line number Diff line number Diff line
@@ -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);

}



/**