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

[Nikolay Borisov <nborisov@suse.com>]

On 7.02.20 г. 12:02 ч., Qu Wenruo wrote:
> 
> 
> 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


Good point.

> 
> Thanks,
> Qu
> 
>>
>>>  }
>>>  
>>>  # _require_btrfs_command <command> [<subcommand>|<option>]
>>>