Re: [xfstests PATCH v3] generic: add a partial pages zeroing out test

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Jan 08, 2025 at 04:44:07PM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@huawei.com>
> 
> This addresses a data corruption issue encountered during partial page
> zeroing in ext4 which the block size is smaller than the page size [1].
> Add a new test which is expanded upon generic/567, this test performs a
> zeroing range test that spans two partial pages to cover this case, and
> also generalize it to work for non-4k page sizes.
> 
> Link: https://lore.kernel.org/linux-ext4/20241220011637.1157197-2-yi.zhang@huaweicloud.com/ [1]
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>

LGTM now, thanks for setting this up!
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
> v2->v3:
>  - Put the verifyfile in $SCRATCH_MNT and remove the overriding
>    _cleanup.
>  - Correct the test name.
> v1->v2:
>  - Add a new test instead of modifying generic/567.
>  - Generalize the test to work for non-4k page sizes.
> v2: https://lore.kernel.org/fstests/20241225125120.1952219-1-yi.zhang@huaweicloud.com/
> v1: https://lore.kernel.org/fstests/20241223023930.2328634-1-yi.zhang@huaweicloud.com/
> 
>  tests/generic/758     | 68 +++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/758.out |  3 ++
>  2 files changed, 71 insertions(+)
>  create mode 100755 tests/generic/758
>  create mode 100644 tests/generic/758.out
> 
> diff --git a/tests/generic/758 b/tests/generic/758
> new file mode 100755
> index 00000000..bf0a342b
> --- /dev/null
> +++ b/tests/generic/758
> @@ -0,0 +1,68 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2024 Huawei.  All Rights Reserved.
> +#
> +# FS QA Test No. 758
> +#
> +# Test mapped writes against zero-range to ensure we get the data
> +# correctly written. This can expose data corruption bugs on filesystems
> +# where the block size is smaller than the page size.
> +#
> +# (generic/567 is a similar test but for punch hole.)
> +#
> +. ./common/preamble
> +_begin_fstest auto quick rw zero
> +
> +# Import common functions.
> +. ./common/filter
> +
> +_require_scratch
> +_require_xfs_io_command "fzero"
> +
> +verifyfile=$SCRATCH_MNT/verifyfile
> +testfile=$SCRATCH_MNT/testfile
> +
> +pagesz=$(getconf PAGE_SIZE)
> +
> +_scratch_mkfs > /dev/null 2>&1
> +_scratch_mount
> +
> +_dump_files()
> +{
> +	echo "---- testfile ----"
> +	_hexdump $testfile
> +	echo "---- verifyfile --"
> +	_hexdump $verifyfile
> +}
> +
> +# Build verify file, the data in this file should be consistent with
> +# that in the test file.
> +$XFS_IO_PROG -f -c "pwrite -S 0x58 0 $((pagesz * 3))" \
> +		-c "pwrite -S 0x59 $((pagesz / 2)) $((pagesz * 2))" \
> +		$verifyfile | _filter_xfs_io >> /dev/null
> +
> +# Zero out straddling two pages to check that the mapped write after the
> +# range-zeroing are correctly handled.
> +$XFS_IO_PROG -t -f \
> +	-c "pwrite -S 0x58 0 $((pagesz * 3))" \
> +	-c "mmap -rw 0 $((pagesz * 3))" \
> +	-c "mwrite -S 0x5a $((pagesz / 2)) $((pagesz * 2))" \
> +	-c "fzero $((pagesz / 2)) $((pagesz * 2))" \
> +	-c "mwrite -S 0x59 $((pagesz / 2)) $((pagesz * 2))" \
> +	-c "close"      \
> +$testfile | _filter_xfs_io > $seqres.full
> +
> +echo "==== Pre-Remount ==="
> +if ! cmp -s $testfile $verifyfile; then
> +	echo "Data does not match pre-remount."
> +	_dump_files
> +fi
> +_scratch_cycle_mount
> +echo "==== Post-Remount =="
> +if ! cmp -s $testfile $verifyfile; then
> +	echo "Data does not match post-remount."
> +	_dump_files
> +fi
> +
> +status=0
> +exit
> diff --git a/tests/generic/758.out b/tests/generic/758.out
> new file mode 100644
> index 00000000..d01c1959
> --- /dev/null
> +++ b/tests/generic/758.out
> @@ -0,0 +1,3 @@
> +QA output created by 758
> +==== Pre-Remount ===
> +==== Post-Remount ==
> -- 
> 2.39.2
> 
>