Re: [PATCH 1/2] xfs: add mount test for read only rt devices

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

On Mon, Jun 09, 2025 at 11:03:53AM +0000, Hans Holmberg wrote:
> Make sure that we can mount rt devices read-only if them themselves
> are marked as read-only.
> 
> Also make sure that rw re-mounts are not allowed if the device is
> marked as read-only.
> 
> Based on generic/050.
> 
> Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com>

Looks fine to me,
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  tests/xfs/837     | 65 +++++++++++++++++++++++++++++++++++++++++++++++
>  tests/xfs/837.out | 10 ++++++++
>  2 files changed, 75 insertions(+)
>  create mode 100755 tests/xfs/837
>  create mode 100644 tests/xfs/837.out
> 
> diff --git a/tests/xfs/837 b/tests/xfs/837
> new file mode 100755
> index 000000000000..61e51d3a7d0e
> --- /dev/null
> +++ b/tests/xfs/837
> @@ -0,0 +1,65 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2009 Christoph Hellwig.
> +# Copyright (c) 2025 Western Digital Corporation
> +#
> +# FS QA Test No. 837
> +#
> +# Check out various mount/remount/unmount scenarious on a read-only rtdev
> +# Based on generic/050
> +#
> +. ./common/preamble
> +_begin_fstest mount auto quick
> +
> +_cleanup_setrw()
> +{
> +	cd /
> +	blockdev --setrw $SCRATCH_RTDEV
> +}
> +
> +# Import common functions.
> +. ./common/filter
> +
> +_fixed_by_kernel_commit bfecc4091e07 \
> +	"xfs: allow ro mounts if rtdev or logdev are read-only"
> +
> +_require_realtime
> +_require_scratch
> +
> +if [ -z "$SCRATCH_RTDEV" ]; then
> +	_notrun "requires external scratch rt device"
> +else
> +	_require_local_device $SCRATCH_RTDEV
> +fi
> +
> +_register_cleanup "_cleanup_setrw"
> +
> +_scratch_mkfs "-d rtinherit" > /dev/null 2>&1
> +
> +#
> +# Mark the rt device read-only.
> +#
> +echo "setting device read-only"
> +blockdev --setro $SCRATCH_RTDEV
> +
> +#
> +# Mount it and make sure it can't be written to.
> +#
> +echo "mounting read-only rt block device:"
> +_scratch_mount 2>&1 | _filter_ro_mount | _filter_scratch
> +if [ "${PIPESTATUS[0]}" -eq 0 ]; then
> +	echo "writing to file on read-only filesystem:"
> +	dd if=/dev/zero of=$SCRATCH_MNT/foo bs=1M count=1 oflag=direct 2>&1 | _filter_scratch
> +else
> +	_fail "failed to mount"
> +fi
> +
> +echo "remounting read-write:"
> +_scratch_remount rw 2>&1 | _filter_scratch | _filter_ro_mount
> +
> +echo "unmounting read-only filesystem"
> +_scratch_unmount 2>&1 | _filter_scratch | _filter_ending_dot
> +
> +# success, all done
> +echo "*** done"
> +status=0
> diff --git a/tests/xfs/837.out b/tests/xfs/837.out
> new file mode 100644
> index 000000000000..0a843a0ba398
> --- /dev/null
> +++ b/tests/xfs/837.out
> @@ -0,0 +1,10 @@
> +QA output created by 837
> +setting device read-only
> +mounting read-only rt block device:
> +mount: device write-protected, mounting read-only
> +writing to file on read-only filesystem:
> +dd: failed to open 'SCRATCH_MNT/foo': Read-only file system
> +remounting read-write:
> +mount: cannot remount device read-write, is write-protected
> +unmounting read-only filesystem
> +*** done
> -- 
> 2.34.1
>