Re: [PATCH v2 6/6] xfs/260: Move xfs/260 to generic

From: Xiao Yang <yangx.jy@cn.fujitsu.com>
To: Ira Weiny <ira.weiny@intel.com>
Cc: Xiao Yang <ice_yangxiao@163.com>, <fstests@vger.kernel.org>,
	<darrick.wong@oracle.com>
Subject: Re: [PATCH v2 6/6] xfs/260: Move xfs/260 to generic
Date: Tue, 30 Jun 2020 15:08:50 +0800	[thread overview]
Message-ID: <5EFAE502.6060805@cn.fujitsu.com> (raw)
In-Reply-To: <20200623180803.GE3910394@iweiny-DESK2.sc.intel.com>

On 2020/6/24 2:08, Ira Weiny wrote:
> On Tue, Jun 23, 2020 at 04:51:31PM +0800, Xiao Yang wrote:
>> On 2020/6/19 23:15, Ira Weiny wrote:
>>> On Thu, Jun 18, 2020 at 11:35:56PM +0800, Xiao Yang wrote:
>>>> On 6/18/20 5:48 AM, Ira Weiny wrote:
>>>>> On Wed, Jun 17, 2020 at 05:32:04PM +0800, Xiao Yang wrote:
>>>>>> From: Xiao Yang<yangx.jy@cn.fujitsu.com>
> [snip]
>
>>>>>     }
>>>>> @@ -124,17 +151,11 @@ do_tests()
>>>>>     # make xfs aligned for PMD fault testing
>>>>>     _scratch_mkfs_geom $(_get_hugepagesize) 1>>   $seqres.full 2>&1
>>>>> -# mount with dax option
>>>>> -_scratch_mount "-o dax"
>>>>> -
>> Hi Ira,
>>
>> Why do you want to remove this combination(i.e. test per-inode DAX flag
>> under mounting with dax option) ?
>> Is it because mounting with dax option ignore FS_XFLAG_DAX flag?
>> I think it is a reasonable combination. :-)
> Yes running with the DAX mount option really does not test anything IMO.
Hi Ira,

Sorry for the late reply because I was busy with other tasks last week. :-)

After reading related code, setting/clearing FS_XFLAG_DAX have no chance 
to change S_DAX
flag if mount with dax option, so I will remove this combination in v3 
patch.

>>>>>     tsize=$((128 * 1024 * 1024))
>>>>> -do_tests
>>>>> -_scratch_unmount
>>>>> -
>>>>>     # mount again without dax option
>>>>>     export MOUNT_OPTIONS=""
>>>>> -_scratch_mount
>>>>> +_scratch_mount "-o dax=inode"
>>>>>     do_tests
>>>>>     # success, all done
>> Could we keep _scratch_mount without dax so that this test can run on both
>> old and new kernel?
>> See the following reasons:
>> 1) FS_XFLAG_DAX was introduced by commit 58f88ca("xfs: introduce per-inode
>> DAX enablement") since 2017.
>> 2) _scratch_mount with dax=inode is equal to _scratch_mount without dax.
> I suppose that would be ok.  But being generic what happens when this runs on
> FS's which don't have the FS_XFLAG_DAX flag?  is it ignored?

Test will report notrun by _require_scratch_dax_iflag() If fs doesn't 
support FS_XFLAG_DAX flag.

> FWIW I believe that any FS (which includes older kernels) which do not support
> dax=inode have no need for this test to run.  The use of FS_XFLAG_DAX on older
> xfs does not do anything and simply does not exist elsewhere.  Only FS's which
> support dax=inode have behavior which needs to be tested IMO.

I just want to test FS_XFLAG_DAX on older xfs by keeping _scratch_mount 
without dax because
the original test(i.e. xfs/260) is designed to test this point. :-)

BTW:  It seems that older xfs can do dax mmap by setting/clearing  
FS_XFLAG_DAX, or do I miss something?

Best Regards,
Xiao Yang
> Ira
>
>> Best Regards,
>> Xiao Yang
>>> .
>>>
>>
> .
>