xfs_io '-d' specifies direct IO, not sync IO.
Signed-off-by: Wang Sheng-Hui <shhuiw@foxmail.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
# create file with sync I/O
$XFS_IO_PROG -f -s -c 'pwrite -b 4k -S 0x34 0 4k' sync_file > /dev/null
-# create file with sync I/O
+# create file with direct I/O
$XFS_IO_PROG -f -d -c 'pwrite -b 4k -S 0x56 0 4k' direct_file > /dev/null
# create file, truncate and then dirty again