Re: [PATCH v2 00/13] NFS client user xattr (RFC8276) support

From: "Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>
To: Anna Schumaker <anna.schumaker@netapp.com>
Cc: linux-nfs <linux-nfs@vger.kernel.org>,
	Trond Myklebust <trond.myklebust@hammerspace.com>,
	Frank van der Linden <fllinden@amazon.com>
Subject: Re: [PATCH v2 00/13] NFS client user xattr (RFC8276) support
Date: Mon, 8 Jun 2020 18:37:29 +0200 (CEST)
Message-ID: <743392222.977980.1591634249190.JavaMail.zimbra@desy.de> (raw)
In-Reply-To: <CAFX2JfkeJ=rqLkt6ce2GsLqmEx2H738skH9GUwVtRPCEyTfo9Q@mail.gmail.com>

Thanks for clarification.

Tigran.

----- Original Message -----
> From: "Anna Schumaker" <anna.schumaker@netapp.com>
> To: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>
> Cc: "linux-nfs" <linux-nfs@vger.kernel.org>, "Trond Myklebust" <trond.myklebust@hammerspace.com>, "Frank van der Linden"
> <fllinden@amazon.com>
> Sent: Monday, June 8, 2020 6:15:06 PM
> Subject: Re: [PATCH v2 00/13] NFS client user xattr (RFC8276) support

> Hi Tigran,
> 
> 
> On Mon, Jun 8, 2020 at 11:59 AM Mkrtchyan, Tigran
> <tigran.mkrtchyan@desy.de> wrote:
>>
>>
>> Dear maintainers,
>>
>> are those changes considered for 5.8?
> 
> My understanding is that these patches will be targeting 5.9.
> 
> Anna
>>
>> Thanks,
>>    Tigran.
>>
>> ----- Original Message -----
>> > From: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>
>> > To: "Frank van der Linden" <fllinden@amazon.com>
>> > Cc: "linux-nfs" <linux-nfs@vger.kernel.org>, "Anna Schumaker"
>> > <anna.schumaker@netapp.com>, "Trond Myklebust"
>> > <trond.myklebust@hammerspace.com>
>> > Sent: Saturday, April 4, 2020 2:18:54 PM
>> > Subject: Re:[PATCH v2 00/13] NFS client user xattr (RFC8276) support
>>
>> > After adding 'minimal' 4.2 implementation to our server, the patchset works as
>> > expected.
>> > Thanks, Tigran.
>> >
>> > -------- Original message --------
>> > From: "Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>
>> > Date: Fri, Mar 27, 2020, 08:51
>> > To: Frank van der Linden <fllinden@amazon.com>
>> > Cc: linux-nfs <linux-nfs@vger.kernel.org>, Anna Schumaker
>> > <anna.schumaker@netapp.com>, Trond Myklebust <trond.myklebust@hammerspace.com>
>> > Subject: Re: [PATCH v2 00/13] NFS client user xattr (RFC8276) support
>> >
>> >
>> > ----- Original Message -----
>> >> From: "Frank van der Linden" <fllinden@amazon.com>
>> >> To: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>
>> >> Cc: "linux-nfs" <linux-nfs@vger.kernel.org>, "Anna Schumaker"
>> >> <anna.schumaker@netapp.com>, "Trond Myklebust"
>> >> <trond.myklebust@hammerspace.com>
>> >> Sent: Friday, March 27, 2020 12:16:02 AM
>> >> Subject: Re: [PATCH v2 00/13] NFS client user xattr (RFC8276) support
>> >
>> >> On Thu, Mar 26, 2020 at 08:03:13PM +0100, Mkrtchyan, Tigran wrote:
>> >>> The new patchset looks broken to me.
>> >>>
>> >>> Client quiryes for supported attributes and gets xattr_support bit set:
>> >>>
>> >>> Mar 26 11:27:07 ani.desy.de kernel: decode_attr_supported:
>> >>> bitmask=fcffbfff:40fdbe3e:00040800
>> >>>
>> >>> However, the attribute never queries, but client makes is decision:
>> >>>
>> >>> Mar 26 11:27:07 ani.desy.de kernel: decode_attr_xattrsupport: XATTR
>> >>> support=false
>> >>>
>> >>> The packets can be found here: https://sas.desy.de/index.php/s/GEPiBxPg3eR4aGA
>> >>>
>> >>> Can you provide packets of your mount/umount round.
>> >>
>> >> Hi Tigran,
>> >>
>> >> I looked at your packet dump. It seems like your server only supports 4.1,
>> >> not 4.2. xattr support builds on 4.2 (within the rules laid out in
>> >> RFC 8178).
>> >
>> > That's right, this is what rfc8276 says:
>> >
>> >   Note that the XDR code contained in this document depends on types
>> >   from the NFSv4.2 nfs4_prot.x file [RFC7863].  This includes both nfs
>> >   types that end with a 4, such as nfs_cookie4, count4, etc., as well
>> >   as more-generic types, such as opaque and bool.
>> >
>> > However, xattr support doesn't relays on any functionality provided by v4.2.
>> > Moreover,
>> > all used data structures (nfs_cookie4, component4, change_info4) defined in
>> > nfsv4.0.
>> > Thus there are no reasons why even v4.0 server can't support xattrs.
>> >
>> >>
>> >> So, the fsinfo client call, which is just a GETATTR, masks out the 4.2
>> >> fattr bits from server->attr_mask, and just uses the 4.1 bits. Meaning that
>> >> xattr_support is not included, and defaults to false.
>> >
>> > I was expecting something like this, but was unable to find the place where this
>> > masking is happening.
>> >
>> > Tigran.
>> >
>> >>
>> >> The packet dump also indicates that your server advertises the xattr_support
>> >> fattr as supported, even though it's in a 4.1 session, which would not
>> >> be correct.
>> >>
> > > > - Frank