diff --git a/include/fs/mufs.h b/include/fs/mufs.h
index bd59e96..32e5694 100644
--- a/include/fs/mufs.h
+++ b/include/fs/mufs.h
@@ -3,6 +3,7 @@
 struct flash_dev;
 
 struct mufs_tree {
+	uint32_t file_size;
 	uint32_t root;
 	uint8_t depth;
 };