Re: [PATCH 1/3] fstests: btrfs: Use word mathcing for _btrfs_get_subvolid()

[Nikolay Borisov <nborisov@suse.com>]

On 7.02.20 г. 3:59 ч., Qu Wenruo wrote:
> Current _btrfs_get_subvolid() can't handle the following case at all:
>   # btrfs subvol list $SCRATCH_MNT
>   ID 256 gen 9 top level 5 path subv1
>   ID 257 gen 7 top level 256 path subv1/subv2
>   ID 258 gen 8 top level 256 path subv1/subv3
>   ID 259 gen 9 top level 256 path subv1/subv4
> 
> If we call "_btrfs_get_subvolid $SCRATCH_MNT subv1" we will get a list
> of all subvolumes, not the subvolid of subv1.
> 
> To address this problem, we go egrep to match $name which starts with a
> space, and at the end of a line.
> So that all other subvolumes won't hit.
> 
> Suggested-by: Josef Bacik <josef@toxicpanda.com>
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> ---
>  common/btrfs | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/common/btrfs b/common/btrfs
> index 19ac7cc4..85b33e4c 100644
> --- a/common/btrfs
> +++ b/common/btrfs
> @@ -7,7 +7,7 @@ _btrfs_get_subvolid()
>  	mnt=$1
>  	name=$2
>  
> -	$BTRFS_UTIL_PROG sub list $mnt | grep $name | awk '{ print $2 }'
> +	$BTRFS_UTIL_PROG sub list $mnt | egrep "\s$name$" | awk '{ print $2 }'

nit: But you don't even need egrep for this, you could have simply used
"grep $name$"

>  }
>  
>  # _require_btrfs_command <command> [<subcommand>|<option>]
>