1 files changed, 51 insertions, 18 deletions

diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 0ddc6d61c55a..5ef72599a581 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -278,31 +278,57 @@ out:
         return ret;
 }
 
-#if 0 /* this will get used when snapshot deletion is implemented */
 int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
                        struct btrfs_root *tree_root,
-                       u64 root_id, u8 type, u64 ref_id)
+                       u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
+                       const char *name, int name_len)
+
 {
+        struct btrfs_path *path;
+        struct btrfs_root_ref *ref;
+        struct extent_buffer *leaf;
         struct btrfs_key key;
+        unsigned long ptr;
+        int err = 0;
         int ret;
-        struct btrfs_path *path;
 
         path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
 
         key.objectid = root_id;
-        key.type = type;
+        key.type = BTRFS_ROOT_BACKREF_KEY;
         key.offset = ref_id;
-
+again:
         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
-        BUG_ON(ret);
-
-        ret = btrfs_del_item(trans, tree_root, path);
-        BUG_ON(ret);
+        BUG_ON(ret < 0);
+        if (ret == 0) {
+                leaf = path->nodes[0];
+                ref = btrfs_item_ptr(leaf, path->slots[0],
+                                     struct btrfs_root_ref);
+
+                WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
+                WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
+                ptr = (unsigned long)(ref + 1);
+                WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
+                *sequence = btrfs_root_ref_sequence(leaf, ref);
+
+                ret = btrfs_del_item(trans, tree_root, path);
+                BUG_ON(ret);
+        } else
+                err = -ENOENT;
+
+        if (key.type == BTRFS_ROOT_BACKREF_KEY) {
+                btrfs_release_path(tree_root, path);
+                key.objectid = ref_id;
+                key.type = BTRFS_ROOT_REF_KEY;
+                key.offset = root_id;
+                goto again;
+        }
 
         btrfs_free_path(path);
-        return ret;
+        return err;
 }
-#endif
 
 int btrfs_find_root_ref(struct btrfs_root *tree_root,
                    struct btrfs_path *path,
@@ -319,7 +345,6 @@ int btrfs_find_root_ref(struct btrfs_root *tree_root,
         return ret;
 }
 
-
 /*
  * add a btrfs_root_ref item.  type is either BTRFS_ROOT_REF_KEY
  * or BTRFS_ROOT_BACKREF_KEY.
@@ -335,8 +360,7 @@ int btrfs_find_root_ref(struct btrfs_root *tree_root,
  */
 int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
                        struct btrfs_root *tree_root,
-                       u64 root_id, u8 type, u64 ref_id,
-                       u64 dirid, u64 sequence,
+                       u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
                        const char *name, int name_len)
 {
         struct btrfs_key key;
@@ -346,13 +370,14 @@ int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
         struct extent_buffer *leaf;
         unsigned long ptr;
 
-
         path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
 
         key.objectid = root_id;
-        key.type = type;
+        key.type = BTRFS_ROOT_BACKREF_KEY;
         key.offset = ref_id;
-
+again:
         ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
                                       sizeof(*ref) + name_len);
         BUG_ON(ret);
@@ -366,6 +391,14 @@ int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
         write_extent_buffer(leaf, name, ptr, name_len);
         btrfs_mark_buffer_dirty(leaf);
 
+        if (key.type == BTRFS_ROOT_BACKREF_KEY) {
+                btrfs_release_path(tree_root, path);
+                key.objectid = ref_id;
+                key.type = BTRFS_ROOT_REF_KEY;
+                key.offset = root_id;
+                goto again;
+        }
+
         btrfs_free_path(path);
-        return ret;
+        return 0;
 }