1 files changed, 15 insertions, 1 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index a6170ff19e7f..34cf1f1f47be 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -406,7 +406,6 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
         init_completion(&root->kobj_unregister);
-        init_rwsem(&root->snap_sem);
         root->defrag_running = 0;
         root->defrag_level = 0;
         root->root_key.objectid = objectid;
@@ -498,6 +497,21 @@ insert:
         return root;
 }
 
+struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
+                                        u64 root_objectid)
+{
+        struct btrfs_root *root;
+
+        if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
+                return fs_info->tree_root;
+        if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
+                return fs_info->extent_root;
+
+        root = radix_tree_lookup(&fs_info->fs_roots_radix,
+                                 (unsigned long)root_objectid);
+        return root;
+}
+
 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
                                               struct btrfs_key *location)
 {