From: "Myklebust, Trond" <Trond.Myklebust@netapp.com>
To: Ken Moffat <zarniwhoop@ntlworld.com>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: nfs3 problem with -rc{2,3} : blame
Thread-Topic: nfs3 problem with -rc{2,3} : blame
Thread-Index: AQHNTbfMQXPaY40l50mll7MzWrSjoJcCSNMAgAAAxYA=
Date: Tue, 19 Jun 2012 16:23:23 +0000
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On Tue, 2012-06-19 at 12:20 -0400, Trond Myklebust wrote:
> On Tue, 2012-06-19 at 02:06 +0100, Ken Moffat wrote:
> > On Mon, Jun 18, 2012 at 11:10:52PM +0100, Ken Moffat wrote:
> > > On Mon, Jun 18, 2012 at 10:03:24PM +0000, Myklebust, Trond wrote:
> > > > 
> > > > Doesn't 4f97615d19 fix the fs/nfs/direct.c problem too? It should.
> > > > 
> > > > Anyhow, if you can apply that on top of the commits that didn't compile,
> > > > and then continue the bisection, that would be great. We definitely do
> > > > want the !defined(CONFIG_NFS_V4) case to work in 3.5-final...
> > > > 
> > >  OK (I was assuming errors in different places were from different
> > > causes).  I'll do that after I've rerun rc3 without NFS_V4 with
> > > SUNRPC_DEBUG.  Thanks.
> > 
> > Bisection now points to:
> > 
> > 6d74743b088d116e31fe1b73f47e782ee2016b94 is the first bad commit
> > commit 6d74743b088d116e31fe1b73f47e782ee2016b94
> > Author: Trond Myklebust <Trond.Myklebust@netapp.com>
> > Date:   Mon Apr 30 13:27:31 2012 -0400
> > 
> >     NFS: Simplify O_DIRECT page referencing
> >     
> >     The O_DIRECT code shouldn't need to hold 2 references to each
> > page. The
> >     reference held by the struct nfs_page should suffice.
> >     
> >     Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
> >     Cc: Fred Isaman <iisaman@netapp.com>
> > 
> >  I was going to revert that from 3.5.0-rc3 to confirm that my
> > problem with backups was gone, and then give it more extended
> > testing to prove firefox downloads were ok, but 6 of 11 hunks
> > failed, the code has changed and I'm not familiar with it.
> 
> However you are saying that the problem is there when you compile a
> kernel with this commit as the head, and it goes away when you compile a
> kernel with commit 3e9e0ca3f19e911ce13c2e6c9858fcb41a37496c as the head?
> 
> I'm confused as to how a bug in that patch could depend on
> CONFIG_NFS_V4, but I'll see what I can find.

By the way, I thought your test-case was doing firefox downloads. Do
those really use O_DIRECT?

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com

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