-run_check $SUDO_HELPER $TOP/btrfs filesystem label $TEST_MNT a
-run_check $SUDO_HELPER $TOP/btrfs filesystem label $TEST_MNT
-run_check $SUDO_HELPER $TOP/btrfs filesystem label $TEST_MNT ''
+run_check $SUDO_HELPER "$TOP/btrfs" filesystem label "$TEST_MNT" a
+run_check $SUDO_HELPER "$TOP/btrfs" filesystem label "$TEST_MNT"
+run_check $SUDO_HELPER "$TOP/btrfs" filesystem label "$TEST_MNT" ''