Re: [PATCH] fstests: btrfs/301: handle auto-removed qgroups

[Boris Burkov <boris@bur.io>]

On Tue, May 07, 2024 at 04:36:06PM +0930, Qu Wenruo wrote:
> There are always attempts to auto-remove empty qgroups after dropping a
> subvolume.
> 
> For squota mode, not all qgroups can or should be dropped, as there are
> common cases where the dropped subvolume are still referred by other
> snapshots.
> In that case, the numbers can only be freed when the last referencer
> got dropped.
> 
> The latest kernel attempt would only try to drop empty qgroups for
> squota mode.
> But even with such safe change, the test case still needs to handle
> auto-removed qgroups, by explicitly echoing "0", or later calculation
> would break bash grammar.
> 
> This patch would add extra handling for such removed qgroups, to be
> future proof for qgroup auto-removal behavior change.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Looks good, thanks!
Reviewed-by: Boris Burkov <boris@bur.io>

> ---
>  tests/btrfs/301 | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/btrfs/301 b/tests/btrfs/301
> index db469724..bb18ab04 100755
> --- a/tests/btrfs/301
> +++ b/tests/btrfs/301
> @@ -51,9 +51,17 @@ _require_fio $fio_config
>  get_qgroup_usage()
>  {
>  	local qgroupid=$1
> +	local output
>  
> -	$BTRFS_UTIL_PROG qgroup show --sync --raw $SCRATCH_MNT | \
> -				grep "$qgroupid" | $AWK_PROG '{print $3}'
> +	output=$($BTRFS_UTIL_PROG qgroup show --sync --raw $SCRATCH_MNT | \
> +		 grep "$qgroupid" | $AWK_PROG '{print $3}')
> +	# The qgroup is auto-removed, this can only happen if its numbers are
> +	# already all zeros, so here we only need to explicitly echo "0".
> +	if [ -z "$output" ]; then
> +		echo "0"
> +	else
> +		echo "$output"
> +	fi
>  }
>  
>  get_subvol_usage()
> -- 
> 2.44.0
>