Once a while, overlayfs whiteout can be visible if upper fs
does not support d_type(ftype/filetype). Test as a sanity
check on whiteout of regular files, links, dirs, devices
and pipes.
Signed-off-by: Xiong Zhou <xzhou@redhat.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>