Re: [PATCH] generic/520: use fsync instead of sync during clean_dir

[Yang Xu <xuyang2018.jy@cn.fujitsu.com>]

on 2019/12/14 4:42, Darrick J. Wong wrote:
> On Fri, Dec 13, 2019 at 01:45:41PM +0800, Yang Xu wrote:
>> When I test this case on xfs, it may fail as below:
>> --------------------------------------------
>>   === link SCRATCH_MNT/A/foo SCRATCH_MNT/bar  with fsync SCRATCH_MNT/A ===
>> +umount: /mnt/xfstests/scratch: target is busy.
>> +        (In some cases useful info about processes that use
>> +         the device is found by lsof(8) or fuser(1))
>> ---------------------------------------------
>>
>> I think we don't need to sync all fs and fsync SCRATCH_MNT is enough.
>>
>> Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
>> ---
>>   tests/generic/520 | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tests/generic/520 b/tests/generic/520
>> index 167d7077..a16467ca 100755
>> --- a/tests/generic/520
>> +++ b/tests/generic/520
>> @@ -58,7 +58,7 @@ clean_dir()
>>   {
>>   	_mount_flakey
>>   	rm -rf $(find $SCRATCH_MNT/* | grep -v "lost+found")
>> -	sync
>> +	$XFS_IO_PROG -c "fsync" $SCRATCH_MNT
> 
> But that only has to force the scratch mount directory to disk.
> 
> Assuming the test authors really meant "write all of the scratch fs'
> dirty data/metadata to disk", I think you want:
> 
>   $XFS_IO_PROG -c syncfs $SCRATCH_MNT
> 
> here?
My xfsprogs version doesn't support syncfs command. Or, we can use fsync 
to make four files(foo bar A/foo A/bar) write to disk?
> 
> Also, why did umount spit out 'target is busy' here?  clean_dir() erases
> the scratch fs between tests, there shouldn't be anything flakey about
> that.
I try to find the cause of this but fail. I debug it but no useful 
output(using  _unmount_flakey  || fuser -uvm $SCRATCH_MNT ), failed as 
below:
umount: /mnt/xfstests/scratch: target is busy.
         (In some cases useful info about processes that use
          the device is found by lsof(8) or fuser(1))
                      USER        PID ACCESS COMMAND
/mnt/xfstests/scratch:
                      root     kernel mount (root)/mnt/xfstests/scratch

ps: My test machine only excutes this cases and doesn't do other  things.

> 
> --D
> 
>>   	_unmount_flakey
>>   }
>>   
>> -- 
>> 2.18.0
>>
>>
>>
> 
>