Hi Greg and Ben,

Attached is the patch of upstream commit fe6e1e8d9fad86873eb74a26e80a8f91f9e870b5 backported to 3.4.20 stable branch (head 0f4475cfaaf80e34ea5496a93ce579fe8c6950d5).

Thanks,
Tao

________________________________________
From: Peng, Tao
Sent: Friday, November 30, 2012 11:34 PM
To: Myklebust, Trond; Greg Kroah-Hartman; Ben Hutchings
Cc: linux-kernel@vger.kernel.org; stable@vger.kernel.org; kernel-team@lists.ubuntu.com; Herton Ronaldo Krzesinski
Subject: RE: [PATCH 041/270] pnfsblock: fix partial page buffer wirte

Sorry for the late response. I will get it done in the weekend. The only one that need backport is bellow patch. The two DIO patches are not necessary because 3.4 NFS DIO does not support pNFS yet.

Thanks,
Tao
________________________________________
From: Myklebust, Trond [Trond.Myklebust@netapp.com]
Sent: Friday, November 30, 2012 9:48 PM
To: Greg Kroah-Hartman; Ben Hutchings
Cc: Peng, Tao; linux-kernel@vger.kernel.org; stable@vger.kernel.org; kernel-team@lists.ubuntu.com; Herton Ronaldo Krzesinski
Subject: RE: [PATCH 041/270] pnfsblock: fix partial page buffer wirte

> -----Original Message-----
> From: Greg Kroah-Hartman [mailto:gregkh@linuxfoundation.org]
> Sent: Thursday, November 29, 2012 8:46 PM
> To: Ben Hutchings
> Cc: Peng Tao; Myklebust, Trond; linux-kernel@vger.kernel.org;
> stable@vger.kernel.org; kernel-team@lists.ubuntu.com; Herton Ronaldo
> Krzesinski
> Subject: Re: [PATCH 041/270] pnfsblock: fix partial page buffer wirte
>
> On Tue, Nov 27, 2012 at 02:33:24AM +0000, Ben Hutchings wrote:
> > On Mon, 2012-11-26 at 14:55 -0200, Herton Ronaldo Krzesinski wrote:
> > > 3.5.7u1 -stable review patch.  If anyone has any objections, please let me
> know.
> > >
> > > ------------------
> > >
> > > From: Peng Tao <bergwolf@gmail.com>
> > >
> > > commit fe6e1e8d9fad86873eb74a26e80a8f91f9e870b5 upstream.
> > >
> > > If applications use flock to protect its write range, generic NFS
> > > will not do read-modify-write cycle at page cache level. Therefore
> > > LD should know how to handle non-sector aligned writes. Otherwise
> > > there will be data corruption.
> > >
> > > Signed-off-by: Peng Tao <tao.peng@emc.com>
> > > Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
> > > Signed-off-by: Herton Ronaldo Krzesinski
> > > <herton.krzesinski@canonical.com>
> > [...]
> >
> > I notice that this fix is missing from 3.4, and will need backporting.
>
> I don't trust myself with backporting this, as I got it wrong.  So if one of the
> NFS developers wants to do this (same goes for the other NFS patch), I'll
> gladly take it.
>

Tao would be the right person to do this since he has access to pNFS blocks hardware and can test the results.

Cheers
  Trond