This test reproduces a race between a direct I/O read and
a mapped write to a hole in a file. On xfs filesystem, it
will trigger a BUG_ON(), and this XFS bug has been fixed by:
04197b3 ("xfs: don't BUG() on mixed direct and mapped I/O")
[ eguan: umount before check dmesg log, and add rw group ]
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>