Re: [PATCH] xfs: add a test that zoned file systems with rump RTG can't be mounted

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

On Wed, Dec 10, 2025 at 03:23:30PM +0100, Christoph Hellwig wrote:
> Garbage collection assumes all zones contain the full amount of blocks.
> Mkfs already ensures this happens, but the kernel mount code did not
> verify this.  Instead such a file system would eventually fail scrub.
> 
> Add a test to verify the new superblock verifier check.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  tests/xfs/651     | 27 +++++++++++++++++++++++++++
>  tests/xfs/651.out |  2 ++
>  2 files changed, 29 insertions(+)
>  create mode 100755 tests/xfs/651
>  create mode 100644 tests/xfs/651.out
> 
> diff --git a/tests/xfs/651 b/tests/xfs/651
> new file mode 100755
> index 000000000000..3aef7a1d016f
> --- /dev/null
> +++ b/tests/xfs/651
> @@ -0,0 +1,27 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2025 Christoph Hellwig.
> +#
> +# FS QA Test No. 651
> +#
> +# Test that the sb verifier rejects zoned file system with rump RTGs.
> +#
> +. ./common/preamble
> +_begin_fstest auto quick zone
> +
> +. ./common/zoned
> +
> +_require_scratch
> +
> +_scratch_mkfs > /dev/null 2>&1
> +blocks=$(_scratch_xfs_db -c 'sb 0' -c 'print rblocks' | awk '{print $3}')

blocks="$(_scratch_xfs_get_metadata_field rblocks 'sb 0')"

> +blocks=$((blocks - 4096))
> +_scratch_xfs_db -x -c 'sb 0' -c "write -d rblocks $blocks" > /dev/null 2>&1
> +_scratch_xfs_db -x -c 'sb 0' -c "write -d rextents $blocks" > /dev/null 2>&1
> +_try_scratch_mount || _notrun "Can't mount rump RTG file system"

Doesn't the _notrun here cause the test to be "skipped" when in fact it
actually exhibits the behavior that you want (i.e. it passes)?

--D

> +
> +# for non-zoned file systems this can succeed
> +_require_xfs_scratch_zoned
> +
> +status=0
> +exit
> diff --git a/tests/xfs/651.out b/tests/xfs/651.out
> new file mode 100644
> index 000000000000..62617d172811
> --- /dev/null
> +++ b/tests/xfs/651.out
> @@ -0,0 +1,2 @@
> +QA output created by 651
> +Can't mount rump RTG file system
> -- 
> 2.47.3
> 
>