linux-ext4 - Re: [PATCH 12/12] xfs/650: require a real SCRATCH

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Message-ID: <20251210194549.GB94594@frogsfrogsfrogs>
Date: Wed, 10 Dec 2025 11:45:49 -0800
From: "Darrick J. Wong" <djwong@...nel.org>
To: Christoph Hellwig <hch@....de>
Cc: Zorro Lang <zlang@...nel.org>, Anand Jain <anand.jain@...cle.com>,
	Filipe Manana <fdmanana@...e.com>, fstests@...r.kernel.org,
	linux-ext4@...r.kernel.org, linux-xfs@...r.kernel.org
Subject: Re: [PATCH 12/12] xfs/650:  require a real SCRATCH_RTDEV

On Wed, Dec 10, 2025 at 06:46:58AM +0100, Christoph Hellwig wrote:
> Require a real SCRATCH_RTDEV instead of faking one up using a loop
> device, as otherwise the options specified in MKFS_OPTIONS might
> not actually work the configuration.
> 
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
>  tests/xfs/650 | 63 +++++----------------------------------------------

Er... what test is xfs/650?  There isn't one in for-next.

--D

>  1 file changed, 6 insertions(+), 57 deletions(-)
> 
> diff --git a/tests/xfs/650 b/tests/xfs/650
> index d8f70539665f..418a1e7aae7c 100755
> --- a/tests/xfs/650
> +++ b/tests/xfs/650
> @@ -9,21 +9,11 @@
>  # bunmapi"). On XFS without the fixes, truncate will hang forever.
>  #
>  . ./common/preamble
> -_begin_fstest auto prealloc preallocrw
> -
> -# Override the default cleanup function.
> -_cleanup()
> -{
> -	_scratch_unmount &>/dev/null
> -	[ -n "$loop_dev" ] && _destroy_loop_device $loop_dev
> -	cd /
> -	rm -f $tmp.*
> -	rm -f "$TEST_DIR/$seq"
> -}
> +_begin_fstest auto prealloc preallocrw realtime
>  
>  . ./common/filter
>  
> -_require_scratch_nocheck
> +_require_realtime
>  _require_xfs_io_command "falloc"
>  
>  maxextlen=$((0x1fffff))
> @@ -31,51 +21,11 @@ bs=4096
>  rextsize=4
>  filesz=$(((maxextlen + 1) * bs))
>  
> -must_disable_feature() {
> -	local feat="$1"
> -
> -	# If mkfs doesn't know about the feature, we don't need to disable it
> -	$MKFS_XFS_PROG --help 2>&1 | grep -q "${feat}=0" || return 1
> -
> -	# If turning the feature on works, we don't need to disable it
> -	_scratch_mkfs_xfs_supported -m "${feat}=1" "${disabled_features[@]}" \
> -		> /dev/null 2>&1 && return 1
> -
> -	# Otherwise mkfs knows of the feature and formatting with it failed,
> -	# so we do need to mask it.
> -	return 0
> -}
> -
> -extra_options=""
> -# Set up the realtime device to reproduce the bug.
> +_scratch_mkfs \
> +	-d agsize=$(((maxextlen + 1) * bs / 2)),rtinherit=1 \
> +	-r extsize=$((bs * rextsize)) \
> +	>>$seqres.full 2>&1
>  
> -# If we don't have a realtime device, set up a loop device on the test
> -# filesystem.
> -if [[ $USE_EXTERNAL != yes || -z $SCRATCH_RTDEV ]]; then
> -	_require_test
> -	loopsz="$((filesz + (1 << 26)))"
> -	_require_fs_space "$TEST_DIR" $((loopsz / 1024))
> -	$XFS_IO_PROG -c "truncate $loopsz" -f "$TEST_DIR/$seq"
> -	loop_dev="$(_create_loop_device "$TEST_DIR/$seq")"
> -	USE_EXTERNAL=yes
> -	SCRATCH_RTDEV="$loop_dev"
> -	disabled_features=()
> -
> -	# disable reflink if not supported by realtime devices
> -	must_disable_feature reflink &&
> -		disabled_features=(-m reflink=0)
> -
> -	# disable rmap if not supported by realtime devices
> -	must_disable_feature rmapbt &&
> -		disabled_features+=(-m rmapbt=0)
> -fi
> -extra_options="$extra_options -r extsize=$((bs * rextsize))"
> -extra_options="$extra_options -d agsize=$(((maxextlen + 1) * bs / 2)),rtinherit=1"
> -
> -_scratch_mkfs $extra_options "${disabled_features[@]}" >>$seqres.full 2>&1
> -_try_scratch_mount >>$seqres.full 2>&1 || \
> -	_notrun "mount failed, kernel doesn't support realtime?"
> -_scratch_unmount
>  _scratch_mount
>  _require_fs_space "$SCRATCH_MNT" $((filesz / 1024))
>  
> @@ -108,7 +58,6 @@ $XFS_IO_PROG -c "pwrite -b 1M -W 0 $(((maxextlen + 2 - rextsize) * bs))" \
>  # Truncate the extents.
>  $XFS_IO_PROG -c "truncate 0" -c fsync "$SCRATCH_MNT/file"
>  
> -# We need to do this before the loop device gets torn down.
>  _scratch_unmount
>  _check_scratch_fs
>  
> -- 
> 2.47.3
> 
>