Re: [PATCH 7/8] common/attr: fix _require_noattr2

["Nirjhar Roy (IBM)" <nirjhar.roy.lists@gmail.com>]

On 10/25/25 03:45, Darrick J. Wong wrote:
> On Fri, Oct 24, 2025 at 02:31:16PM +0530, Nirjhar Roy (IBM) wrote:
>> On Wed, 2025-10-15 at 09:38 -0700, Darrick J. Wong wrote:
>>> From: Darrick J. Wong <djwong@kernel.org>
>>>
>>> attr2/noattr2 doesn't do anything anymore and aren't reported in
>>> /proc/mounts, so we need to check /proc/mounts and _notrun as a result.
>>>
>>> Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
>>> ---
>>>   common/attr |    4 ++++
>>>   1 file changed, 4 insertions(+)
>>>
>>>
>>> diff --git a/common/attr b/common/attr
>>> index 1c1de63e9d5465..35e0bee4e3aa53 100644
>>> --- a/common/attr
>>> +++ b/common/attr
>>> @@ -241,7 +241,11 @@ _require_noattr2()
>>>   		|| _fail "_try_scratch_mkfs_xfs failed on $SCRATCH_DEV"
>>>   	_try_scratch_mount -o noattr2 > /dev/null 2>&1 \
>>>   		|| _notrun "noattr2 mount option not supported on $SCRATCH_DEV"
>>> +	grep -w "$SCRATCH_MNT" /proc/mounts | awk '{print $4}' | grep -q -w noattr2
>> If noatrr2 doesn't do anything, then in that case _try_scratch_mount will ignore noattr2 and mount
>> will succeed. With the above change, we are just checking if noattr2 appears in /proc/mounts(after
>> the mount), if yes then the preconditions returns true, else the test using this precondition is
>> notrun. Right?
> Right.
>
> On a pre-6.18 kernel where noattr2 did something, the following will
> happen:
>
> a) V4 filesystem, noattr2 actually matters for the mount, and it should
> show up in /proc/mounts.  If it doesn't, then the test should not run.
>
> b) V5 filesystem, noattr2 is impossible so the mount fails.  Test will
> not run.
>
> With 6.18 the behavior changes:
>
> a) V4 filesystem, noattr2 doesn't do anything, the mount succeeds, but
> noattr2 does not show up in /proc/mounts.  The test should not run.
>
> b) V5 filesystem, noattr2 now no longer fails the mount but it doesn't
> show up in /proc/mounts either.  The test still should not run.

Okay, makes sense. Thank you for the explanation.

--NR

>
>> This looks okay to me.
>> Reviewed-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>
> Thanks!
>
> --D
>
>> --NR
>>> +	local res=${PIPESTATUS[2]}
>>>   	_scratch_unmount
>>> +	test $res -eq 0 \
>>> +		|| _notrun "noattr2 mount option no longer functional"
>>>   }
>>>   
>>>   # getfattr -R returns info in readdir order which varies from fs to fs.
>>>
>>
-- 
Nirjhar Roy
Linux Kernel Developer
IBM, Bangalore