Re: [PATCH v4 1/5] common/rc: _fs_sysfs_dname fetch fsid using btrfs tool

[David Sterba <dsterba@suse.cz>]

On Thu, Nov 02, 2023 at 07:28:18PM +0800, Anand Jain wrote:
> Currently _fs_sysfs_dname gets fsid from the findmnt command however
> this command provides the metadata_uuid if the device is mounted with
> temp-fsid. So instead, use btrfs filesystem show command to know the fsid.
> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> Reviewed-by: Filipe Manana <fdmanana@suse.com>
> ---
> v3: add local variable fsid
> 
>  common/rc | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/common/rc b/common/rc
> index 259a1ffb09b9..7f14c19ca89e 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -4721,6 +4721,7 @@ _require_statx()
>  _fs_sysfs_dname()
>  {
>  	local dev=$1
> +	local fsid
>  
>  	if [ ! -b "$dev" ]; then
>  		_fail "Usage: _fs_sysfs_dname <mounted_device>"
> @@ -4728,7 +4729,9 @@ _fs_sysfs_dname()
>  
>  	case "$FSTYP" in
>  	btrfs)
> -		findmnt -n -o UUID ${dev} ;;
> +		fsid=$($BTRFS_UTIL_PROG filesystem show ${dev} | grep uuid: | \
> +							$AWK_PROG '{print $NF}')

This could be also added as a subcommand to 'inspect-internal', ie. from
a file to it's filesystem uuid, then it should be easy to get any other
id if needed through the sysfs directory.