Inspired by syncfs bug of overlayfs which does not sync dirtyinodes
in underlying filesystem.
Run syncfs and shutdown filesystem(or underlying filesystem of
overlayfs) to check syncfs result.
Signed-off-by: Chengguang Xu <cgxu519@icloud.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>