[PATCH] xfstests: add simple splice test

[Christoph Hellwig]

> +echo "Feel the serenity."
> +
> +SRC=$TEST_DIR/$seq.src
> +DST=$TEST_DIR/$seq.dst
> +
> +$XFS_IO_PROG -f -c "pwrite -S 0xa5a55a5a 0 32768k" -c fsync $SRC > /dev/null 2>&1
> +$XFS_IO_PROG -f -c "sendfile -i $SRC 0 32768k" -c fsync $DST > /dev/null 2>&1
> +
> +diff $SRC $DST

I think this should removfe the two files to make sure the test is
reproducible and doesn't overwrite an existing file during the second
run.  Also I'd recomment not to redirect the output to /dev/null but use
our normal xfs_io filters and make the output part of the golden output.