diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 721936a..30d24cf 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -185,6 +185,9 @@
 {
 	struct __prelim_ref *ref;
 
+	if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID)
+		return 0;
+
 	ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask);
 	if (!ref)
 		return -ENOMEM;