Re: [PATCH] xfs/298: Add 100ms sleep before scratch_umount

["xuyang2018.jy@fujitsu.com" <xuyang2018.jy@fujitsu.com>]

on 2022/5/9 21:42, Zorro Lang wrote:
> On Mon, May 09, 2022 at 02:56:57PM +0800, Yang Xu wrote:
>> When testing this case on my machine, it reports the following error:
>> umount: /mnt/xfstests/scratch: target is busy.
>> xfs_db: /dev/sda11 contains a mounted filesystem
>>
>> scratch_unmount failed, so  _scratch_xfs_db reports scratch_dev is a
>> mounted filesystem. It seems filesystem has something to be doing.
>>
>> To avoid this, just add a 100ms sleep before scratch_umount.
>>
>> Signed-off-by: Yang Xu<xuyang2018.jy@fujitsu.com>
>> ---
>>   tests/xfs/298 | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/tests/xfs/298 b/tests/xfs/298
>> index b0153ebf..17510379 100755
>> --- a/tests/xfs/298
>> +++ b/tests/xfs/298
>> @@ -51,6 +51,7 @@ while [ $SIZE -lt 1024 ];do
>>   	rm $SYMLINK_FILE
>>   # umount and check the number of extents on the inode. Should be 0.
>>   	cd /
>> +	sleep 0.1
>
> Hi
>
> Actually I was wondering if we can add a while loop trying in _scratch_unmount,
> to avoid some random "device busy" problem, likes:
>
> Change _scratch_unmount to __scratch_unmount, then:
>
> _scratch_unmount()
> {
> 	local n
> 	local is_unmounted=1
>
> 	__scratch_unmount>  $tmp.scratch_unmount.err 2>&1
> 	if [ $? -ne 0 -a "$MULTI_SCRATCH_UNMOUNT" = "yes" ];then
> 		for ((n=0; n<5; n++));do
> 			sleep 0.1
> 			__scratch_unmount>>  $tmp.scratch_unmount.err 2>&1
> 			if [ $? -eq 0 ];then
> 				is_unmounted=0
> 				break
> 			fi
> 		done
> 	else
> 		is_unmounted=0
> 	fi
> 	if [ $is_unmounted -ne 0 ];then
> 		cat $tmp.scratch_unmount.err
> 	fi
> 	rm -f $tmp.scratch_unmount.err
> 	return $is_unmounted
> }
>
> This's just an idea out of my head, hope to hear more suggestions from other
> forks.

I think this suggestion is meaningful and ltp also has a similar C api[1].

But we don't use this api in everywhere in ltp. So I don't use this api 
in everywhere in xfstests and just create a new function name to use it 
in situation that use many times mount/umount.

Also, xfstests some cases need to filter the stderr ie xfs/444.

So I think we can create a api that try to umount many times(5 or10) and
people can use this api if they meet the random ebusy problem instead of 
breaking the now _scratch_unmount api.

What do you think about it?

[1]https://github.com/linux-test-project/ltp/blob/master/lib/tst_device.c#L382

Best Regards
Yang Xu
>
> Thanks,
> Zorro
>
>>   	_scratch_unmount>/dev/null 2>&1
>>   	_scratch_xfs_db  -c "inode $inode" -c "p core.nextents"
>>
>> --
>> 2.23.0
>>