Re: [PATCH] fstests: btrfs/340: add support for older kernels/progs

[Zorro Lang <zlang@kernel.org>]

On Thu, May 14, 2026 at 03:25:02PM +0930, Qu Wenruo wrote:
> The test case will fail on older distros like SLE12-SP5, there are two
> problems on the test case itself:
> 
> - Requires "--sync" option from "btrfs qgroup show" subcommand
>   That option was introduecd in v4.9.1, thus there are still some older
>   distros using that very old version.
> 
> - Not all kernels support quick inherit
>   The kernel commit introducing the quick inherit is 6.9, thus some
>   supported LTS kernels do not have that commit.
> 
>   In that case qgroup will just be marked inconsistent, this will cause
>   the later "btrfs qgroup show" command to output a warning due to the
>   inconsistent flag.
> 
> Fix both problems by:
> 
> - Require "--sync" option from "btrfs qgroup show" subcommand
>   So older distros will just skip the test.
> 
> - Redirect all output from "btrfs qgroup show" to $seqres.full
>   So older kernels can still pass the test case by marking qgroup
>   inconsitent.
> 
> Reported-by: Long An <lan@suse.com>
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>  tests/btrfs/340 | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/tests/btrfs/340 b/tests/btrfs/340
> index 872f790cb975..fc0b8d48adaa 100755
> --- a/tests/btrfs/340
> +++ b/tests/btrfs/340
> @@ -39,7 +39,14 @@ _btrfs qgroup show -p --sync $SCRATCH_MNT >> $seqres.full
>  # without marking qgroup inconsistent.
>  _btrfs subv snap -i 1/1 $SCRATCH_MNT/subv1 $SCRATCH_MNT/snap1
>  echo "After quick inherit:" >> $seqres.full
> -_btrfs qgroup show -p --sync $SCRATCH_MNT >> $seqres.full
> +# Sync the fs so that the qgroup numbers are properly updated.
> +_btrfs filesystem sync $SCRATCH_MNT

Just out of curiosity, `sync $SCRATCH_MNT` can achieve the same effect here, right?
Regardless, it definitely makes more sense to use Btrfs's own sync command in this
context.

Reviewed-by: Zorro Lang <zlang@kernel.org>

> +
> +# Redirect all output to seqres.full including stderr.
> +# For older kernels without quick inherit support, it will mark
> +# qgroup inconsistent, which can pollute the golden output.
> +# Here we rely on the final btrfs check to catch any qgroup number errors.
> +_btrfs qgroup show -p $SCRATCH_MNT >> $seqres.full
>  
>  echo "Silence is golden"
>  _exit 0
> -- 
> 2.54.0
> 
>