diff --git a/fs/fs.c b/fs/fs.c
index 3b5f284..7d8dea7 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -754,7 +754,7 @@
 	}
 
 	fsdev = xzalloc(sizeof(struct fs_device_d));
-	if (!fs_drv->flags & FS_DRIVER_NO_DEV) {
+	if (!(fs_drv->flags & FS_DRIVER_NO_DEV)) {
 		fsdev->backingstore = strdup(device);
 		if (!device) {
 			printf("need a device for driver %s\n", fsname);