diff --git a/simple.c b/simple.c
index 7ae2783..76ec632 100644
--- a/simple.c
+++ b/simple.c
@@ -763,6 +763,7 @@ struct file_system_type simplefs_fs_type = {
 	.name = "simplefs",
 	.mount = simplefs_mount,
 	.kill_sb = simplefs_kill_superblock,
+	.fs_flags = FS_REQUIRES_DEV,
 };
 
 static int simplefs_init(void)