Re: [PATCH v2 3/3] fs: ubifs: set s_uuid in super block

[Richard Weinberger]

Oleksij,

Am 12.04.2017 um 09:15 schrieb Oleksij Rempel:
> On Tue, Apr 11, 2017 at 10:48:28PM -0700, Christoph Hellwig wrote:
>> On Tue, Apr 11, 2017 at 10:43:26PM +0200, Richard Weinberger wrote:
>>> Artem, do you remember why UBIFS didn't set s_uuid in first place?
>>
>> It's an extremely odd field - only a hand full of file systems set it
>> (e.g. XFS doesn't, although according to Mimi IMA supports XFS), and
>> it's never even used outside of the IMA/EVM code.
>>
>> We really need a feature flag that this field is valid that IMA can
>> check before adding more support for it.
> 
> It seems to be used by mm/cleancache.c
> void __cleancache_init_shared_fs()
> 
> but this affects only ocfs2.
> 
> So, if some flag should be implemented, who should do it? :)

I'll not do it for you. ;)

> If me, what flag should be created?

A super block flag that denotes that s_uuid is valid.

Thanks,
//richard