Re: [PATCH v2 4/4] generic: test to run fsx eof pollution

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

On Wed, Aug 28, 2024 at 02:15:34PM -0400, Brian Foster wrote:
> Filesystem regressions related to partial page zeroing can go
> unnoticed for a decent amount of time. A recent example is the issue
> of iomap zero range not handling dirty pagecache over unwritten
> extents, which leads to wrong behavior on certain file extending
> operations (i.e. truncate, write extension, etc.).
> 
> fsx does occasionally uncover these sorts of problems, but failures
> can be rare and/or require longer running tests outside what is
> typically run via full fstests regression runs. fsx now supports a
> mode that injects post-eof data in order to explicitly test partial
> eof zeroing behavior. This uncovers certain problems more quickly
> and applies coverage more broadly across size changing operations.
> 
> Add a new test that runs an fsx instance (modeled after generic/127)
> with eof pollution mode enabled. While the test is generic, it is
> currently limited to XFS as that is currently the only known major
> fs that does enough zeroing to satisfy the strict semantics expected
> by fsx. The long term goal is to uncover and fix issues so more
> filesystems can enable this test.
> 
> Signed-off-by: Brian Foster <bfoster@redhat.com>

Looks good!
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  tests/generic/363     | 23 +++++++++++++++++++++++
>  tests/generic/363.out |  2 ++
>  2 files changed, 25 insertions(+)
>  create mode 100755 tests/generic/363
>  create mode 100644 tests/generic/363.out
> 
> diff --git a/tests/generic/363 b/tests/generic/363
> new file mode 100755
> index 00000000..477c111c
> --- /dev/null
> +++ b/tests/generic/363
> @@ -0,0 +1,23 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2024 Red Hat, Inc.  All Rights Reserved.
> +#
> +# FSQA Test No. 363
> +#
> +# Run fsx with EOF pollution enabled. This provides test coverage for partial
> +# EOF page/block zeroing for operations that change file size.
> +#
> +
> +. ./common/preamble
> +_begin_fstest rw auto
> +
> +_require_test
> +
> +# currently only xfs performs enough zeroing to satisfy fsx
> +_supported_fs xfs
> +
> +# on failure, replace -q with -d to see post-eof writes in the dump output
> +run_fsx "-q -S 0 -e 1 -N 100000"
> +
> +status=0
> +exit
> diff --git a/tests/generic/363.out b/tests/generic/363.out
> new file mode 100644
> index 00000000..3d219cd0
> --- /dev/null
> +++ b/tests/generic/363.out
> @@ -0,0 +1,2 @@
> +QA output created by 363
> +fsx -q -S 0 -e 1 -N 100000
> -- 
> 2.45.0
> 
>