Re: [PATCH] generic/326: basic copy_file_range() correctness

Dave Chinner
2015-05-04T06:40:25Z

On Fri, Apr 10, 2015 at 04:41:08PM -0700, Zach Brown wrote:
> Add basic tests for the copy_file_range() syscall that's being
> developed. This relies on having added copy_file_range() support to
> xfs_io in xfsprogs.
>
> This is a very rough draft. Feedback welcome!
>
> Signed-off-by: Zach Brown <zab@redhat.com>
> ---
> tests/generic/326 | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> tests/generic/group | 1 +

Missing the golden output file.

> +
> +# real QA test starts here
> +
> +_supported_fs generic
> +_supported_os Linux
> +_require_test

_require_xfs_io_command copy_file_range

> +
> +src="$TEST_DIR/src"
> +dst="$TEST_DIR/dst"

Seeing this is on the test device, the files may already exist so
you should remove them to give us a known good starting point.

Also, add $seq to the filename so that we know what test created the
files.

> +$XFS_IO_PROG -ftc "pwrite -S 0x12 0 128k" "$src" | _filter_xfs_io

Add a "-c fsync" to ensure the file is on disk.

> +od -x "$src"

I'd just md5sum the file; if there's a mismatch, the dev can then
look at it in more detail...

> +echo "extend destination file"
> +$XFS_IO_PROG -ftc "copy_file_range -i $src -s 0 -t 0 $((128 * 1024))" "$dst" \
> + | _filter_xfs_io

-t 0 128k ?

Also, the truncate of the destination file is not obvious here,
which is another good reason to rm -rf to begin with.
> +od -x "$dst"

> +echo "copy into previously written region"
> +$XFS_IO_PROG -ft -c "pwrite -S 0xef 0 128k" "$dst" \
> + -c "copy_file_range -i $src -s 0 -t 0 $((128 * 1024))" \
> + | _filter_xfs_io
> +od -x "$dst"

The truncate makes this a write into a delalloc region.

Add a fsync after the write to make it a copy into a written region.

> +echo "copy into fallocate"
> +$XFS_IO_PROG -ft -c "falloc 0 128k" "$dst" \
> + -c "copy_file_range -i $src -s 0 -t 0 $((128 * 1024))" \
> + | _filter_xfs_io
> +od -x "$dst"

"copy into preallocated region"

> +echo "copy from likely sparse source"
> +$XFS_IO_PROG -ft -c "pwrite -S 0x56 96k 32k" "$src" \
> + -c "pwrite -S 0x34 0 32k" | _filter_xfs_io

fsync.

> +$XFS_IO_PROG -ftc "copy_file_range -i $src -s 0 -t 0 $((128 * 1024))" "$dst" \
> + | _filter_xfs_io
> +od -x "$dst"
> +
> +echo "source at eof"
> +$XFS_IO_PROG -ftc \
> + "copy_file_range -i $src -s $((128 * 1024)) -t 0 $((128 * 1024))" \
> + "$dst" | _filter_xfs_io

What is this supposed to leave? An empty file? If so, md5sum will
still verify that...

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com