Re: [PATCH] fstests: generic: add a basic cachestat test case

[Anand Suveer Jain <asj@kernel.org>]

On 7/7/26 08:18, Qu Wenruo wrote:
> The test case is inspired by LTP, where there is a regression on 64K
> page size systems with btrfs, that after a fsync, cachestat() still
> report dirty pages.
> 
> The test case itself is pretty simple, fill the file with a buffered write that is
> 1/2/4/8/16 page sized, call cachestat() to make sure the cached/dirtied
> number match the page number.
> 
> Then do a fsync(), and make sure the dirty page number reduced to 0
> meanwhile cached is still the same.
> 
> Link: https://bugzilla.suse.com/show_bug.cgi?id=1270397
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>  tests/generic/798     | 57 +++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/798.out |  2 ++
>  2 files changed, 59 insertions(+)
>  create mode 100755 tests/generic/798
>  create mode 100644 tests/generic/798.out
> 
> diff --git a/tests/generic/798 b/tests/generic/798
> new file mode 100755
> index 00000000..4328475e
> --- /dev/null
> +++ b/tests/generic/798
> @@ -0,0 +1,57 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2026 SUSE S.A.  All Rights Reserved.
> +#
> +# FS QA Test 798
> +#
> +# Basic tests for cachestate()
> +#
> +. ./common/preamble
> +_begin_fstest auto quick
> +
> +_require_xfs_io_command "cachestat"
> +_require_scratch
> +
> +pagesize=$(_get_page_size)
> +
> +for num_page in 1 2 4 8 16; do
> +	size=$(($pagesize * $num_page))
> +
> +	echo "=== Test with $num_page pages ===" >> $seqres.full
> +	_scratch_mkfs > /dev/null
> +	_scratch_mount
> +
> +	# Basic cached number reporting
> +	$XFS_IO_PROG -f -c "pwrite -b $pagesize 0 $size" \
> +		$SCRATCH_MNT/foobar >> $seqres.full
> +	$XFS_IO_PROG -c "cachestat 0 $size" $SCRATCH_MNT/foobar > $tmp.output
> +	cat $tmp.output >> $seqres.full
> +	cached=$(cat $tmp.output | cut -f1 -d, | awk '{print $2}')
> +	dirtied=$(cat $tmp.output | cut -f2 -d, | awk '{print $2}')
> +
> +	if [ "$cached" -ne "$num_page" ]; then
> +		_fail "cached not matching the page number"
> +	fi
> +
> +	if [ "$cached" -ne "$dirtied" ]; then
> +		_fail "dirited not matching the page number"
> +	fi
> +	$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foobar >> $seqres.full
> +
> +	# Test dirty page number reporting after a fsync.
> +	$XFS_IO_PROG -c "cachestat 0 $size" $SCRATCH_MNT/foobar > $tmp.output
> +	cat $tmp.output >> $seqres.full
> +	_scratch_unmount
> +	cached=$(cat $tmp.output | cut -f1 -d, | awk '{print $2}')
> +	dirtied=$(cat $tmp.output | cut -f2 -d, | awk '{print $2}')
> +
> +	if [ "$cached" -ne "$num_page" ]; then
> +		_fail "cached not matching the page number"
> +	fi
> +	if [ "$dirtied" -ne 0 ]; then
> +		_fail "dirtied pages not zero"
> +	fi
> +done
> +
> +echo "Silence is golden"
> +_exit 0
> diff --git a/tests/generic/798.out b/tests/generic/798.out
> new file mode 100644
> index 00000000..216d6e93
> --- /dev/null
> +++ b/tests/generic/798.out
> @@ -0,0 +1,2 @@
> +QA output created by 798
> +Silence is golden


Nice.

Reviewed-by: Anand Jain <asj@kernel.org>


Thanks