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

[Qu Wenruo <wqu@suse.com>]

On 2020/2/7 下午5:41, Nikolay Borisov wrote:
> 
> 
> 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 $name$"

That \s is needed. Or the following case can't be handled:

   ID 256 gen 9 top level 5 path subv1
   ID 257 gen 7 top level 256 path subv1/subv1

Thanks,
Qu

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