diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index ec30aae..8d76422 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -4,4 +4,4 @@
 
 obj-y := btrfs.o chunk-map.o compression.o ctree.o dev.o dir-item.o \
 	extent-io.o inode.o root.o subvolume.o crypto/hash.o disk-io.o \
-	common/rbtree-utils.o extent-cache.o volumes.o
+	common/rbtree-utils.o extent-cache.o volumes.o root-tree.o