Re: [PATCH 2/5] common/btrfs: quota mode helpers

[Anand Jain <anand.jain@oracle.com>]

On 06/07/2023 07:42, Boris Burkov wrote:
> To facilitate skipping tests depending on the qgroup mode after mkfs,
> add support for figuring out the mode. This cannot just rely on the new
> sysfs file, since it might not be present on older kernels.
> 
> Signed-off-by: Boris Burkov <boris@bur.io>
> ---
>   common/btrfs | 43 +++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 43 insertions(+)
> 
> diff --git a/common/btrfs b/common/btrfs
> index 175b33aee..66c065a10 100644
> --- a/common/btrfs
> +++ b/common/btrfs
> @@ -680,3 +680,46 @@ _require_btrfs_scratch_logical_resolve_v2()
>   	fi
>   	_scratch_unmount
>   }
> +
> +_qgroup_mode_file()
> +{
> +	local mnt=$1
> +
> +	uuid=$(findmnt -n -o UUID $mnt)
> +	echo /sys/fs/btrfs/${uuid}/qgroups/mode
> +}


> +
> +_qgroup_enabled_file()
> +{
> +	local mnt=$1
> +
> +	uuid=$(findmnt -n -o UUID $mnt)


> +	echo /sys/fs/btrfs/${uuid}/qgroups/enabled
> +}
> +


> +_qgroup_mode()
> +{
> +	local mnt=$1
> +
> +	if [ ! -f "$(_qgroup_enabled_file $mnt)" ]; then
> +		echo "disabled"
> +		return
> +	fi
> +
> +	if [ -f "$(_qgroup_mode_file $mnt)" ]; then
> +		cat $(_qgroup_mode_file $mnt)
> +	elif [ $(cat $(_qgroup_enabled_file $mnt)) -eq "1" ]; then
/> +		echo "qgroup"
> +	else
> +		echo "disabled" # should not be reachable, the enabled file won't exist.
> +	fi
> +}
> +
> +_require_scratch_qgroup()
> +{
> +	_scratch_mkfs >>$seqres.full 2>&1
> +	_scratch_mount
> +	_run_btrfs_util_prog quota enable $SCRATCH_MNT
> +	_check_regular_qgroup $SCRATCH_MNT || _notrun "not running normal qgroups"
> +	_scratch_unmount
> +}


Can you add _has_scratch_fs_sysfs() helper for scratch?  See for example 
_has_fs_sysfs().

So that you can do something like..

if [ _has_scratch_fs_sysfs qgroups/mode ]; then
	if [ $(_get_fs_sysfs_attr $mnt qgroups/mode) == 1 ]; then
		echo qgroup
	else
		echo something
else
	_notrun "qgroup unsupported"
fi


Thanks, Anand