Re: [PATCH 1/3] xfs: add a test that zoned file systems with rump RTG can't be mounted

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

On Thu, Dec 18, 2025 at 05:10:16PM +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     | 33 +++++++++++++++++++++++++++++++++
>  tests/xfs/651.out |  2 ++
>  2 files changed, 35 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..1e36fec408ff
> --- /dev/null
> +++ b/tests/xfs/651
> @@ -0,0 +1,33 @@
> +#! /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
> +
> +# we intentionally corrupt the superblock
> +_require_scratch_nocheck
> +
> +_try_scratch_mkfs_xfs -r zoned=1 >> $seqres.full 2>&1 || \
> +	_notrun "Can't create zoned file system"
> +
> +# adjust rblocks/rextents to not be zone aligned
> +blocks=$(_scratch_xfs_get_sb_field rblocks)
> +blocks=$((blocks - 4096))
> +_scratch_xfs_set_sb_field rblocks ${blocks} >> $seqres.full 2>&1
> +_scratch_xfs_set_sb_field rextents ${blocks} >> $seqres.full 2>&1
> +
> +if _try_scratch_mount >/dev/null 2>&1; then
> +	echo "Mounted rump RTG file system (bad)"
> +fi
> +
> +echo "Can't mount rump RTG file system (good)"

In theory this should be in an else clause, but as extra lines in the
golden output is enough to fail the test, this code flow is correct.

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> +
> +status=0
> +exit
> diff --git a/tests/xfs/651.out b/tests/xfs/651.out
> new file mode 100644
> index 000000000000..5d491b1894ea
> --- /dev/null
> +++ b/tests/xfs/651.out
> @@ -0,0 +1,2 @@
> +QA output created by 651
> +Can't mount rump RTG file system (good)
> -- 
> 2.47.3
> 
>