Test mkfs against thin provision device, which has very small
backing size and very big virtual size. mkfs should return error
when it hits EIO.
Signed-off-by: Boyang Xue <bxue@redhat.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>