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>

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 911a9db801e0a776a9a960180fb2b95f0ec14863..df7a803005fbf6b4ebdd080cd103667822797768 100644 (file)
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -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 @@ 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);
 }
 
 /**