Re: [PATCH] fstests: btrfs/179 call quota rescan

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

On 7/2/20 8:15 PM, Qu Wenruo wrote:
> 
> 
> On 2020/2/7 下午8:01, Anand Jain wrote:
>> On some systems btrfs/179 fails as the check finds that there is
>> difference in the qgroup counts.
>>
>> By the async nature of qgroup tree scan, the latest qgroup counts at the
>> time of umount might not be upto date,
> 
> Yes, so far so good.
> 
>> if it isn't then the check will
>> report the difference in count. The difference in qgroup counts are anyway
>> updated in the following mount, so it is not a real issue that this test
>> case is trying to verify.
> 
> No problem either.
> 
>> So make sure the qgroup counts are updated
>> before unmount happens and make the check happy.
> 
> But the solution doesn't look correct to me.
> 
> We should either make btrfs-check to handle such half-dropped case
> better,

  Check is ok. The count as check counts matches with the count after 
the mount. So what is recorded in the qgroup is not upto date.

> or find a way to wait for all subvolume drop to be finished in
> test case.

Yes this is one way. Just wait for few seconds will do, test passes. Do 
you know any better way?

Thanks, Anand

> Papering the test by rescan is not a good idea at all.
> If one day we really hit some qgroup accounting problem, this papering
> way could hugely reduce the coverage.
> 


> Thanks,
> Qu
> 
>>
>> Signed-off-by: Anand Jain <anand.jain@oracle.com>
>> ---
>>   tests/btrfs/179 | 8 ++++++++
>>   1 file changed, 8 insertions(+)
>>
>> diff --git a/tests/btrfs/179 b/tests/btrfs/179
>> index 4a24ea419a7e..74e91841eaa6 100755
>> --- a/tests/btrfs/179
>> +++ b/tests/btrfs/179
>> @@ -109,6 +109,14 @@ wait $snapshot_pid
>>   kill $delete_pid
>>   wait $delete_pid
>>   
>> +# By the async nature of qgroup tree scan, the latest qgroup counts at the time
>> +# of umount might not be upto date, if it isn't then the check will report the
>> +# difference in count. The difference in qgroup counts are anyway updated in the
>> +# following mount, so it is not a real issue that this test case is trying to
>> +# verify. So make sure the qgroup counts are updated before unmount happens.
>> +
>> +$BTRFS_UTIL_PROG quota rescan -w $SCRATCH_MNT >> $seqres.full
>> +
>>   # success, all done
>>   echo "Silence is golden"
>>   
>>
>