Date: Thu, 24 Feb 2011 19:06:27 +0530
From: Shiraz Hashim <shiraz.hashim@st.com>
To: Chuck Lever <chuck.lever@oracle.com>
Cc: Brian Downing <bdowning@lavos.net>, Deepak SIKRI <deepak.sikri@st.com>,
        Armando VISCONTI <armando.visconti@st.com>,
        Trond Myklebust <Trond.Myklebust@netapp.com>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        Viresh KUMAR <viresh.kumar@st.com>,
        Peppe CAVALLARO <peppe.cavallaro@st.com>, amitgoel <amit.goel@st.com>
Subject: Re: STMMAC driver: NFS Problem on 2.6.37
Message-ID: <20110224133627.GO920@DLHLAP0379>
References: <2D04CF75-CA68-4BDC-99A3-FA1DD6113602@oracle.com>
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 <4D3EBA54.4020308@st.com>
 <EFFBD485-8B7E-44D1-A8D2-61E73BF42DF9@oracle.com>
 <20110209200129.GA6402@glaurung.lavos.net>
 <D031EAC4-68E9-4E56-8DB3-208B34C8DFD7@oracle.com>
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On Thu, Feb 10, 2011 at 05:26:16AM +0800, Chuck Lever wrote:
> 
> On Feb 9, 2011, at 3:58 PM, Brian Downing wrote:
> 
> > On Wed, Feb 09, 2011 at 03:12:22PM -0500, Chuck Lever wrote:
> >> Based on your console logs, I see that the working case uses UDP to
> >> contact the server's mountd, but the failing case uses TCP.  You can
> >> try explicitly specifying "proto=udp" to force the use of UDP, to test
> >> this theory.
> > 
> > This does indeed make it work again for me, thanks!
> > 
> >> Meanwhile, the patch description explicitly states that the default
> >> mount option settings have changed.  Does it make sense to change the
> >> default behavior of NFSROOT mounts to use UDP again?  I don't see
> >> another way to make this process more reliable across NIC
> >> initialization.  If this is considered a regression, we can make a
> >> patch for 2.6.38-rc and 2.6.37.
> > 
> > I only use nfsroot for development, so I don't have a terribly strong
> > opinion.  I would point out though that the default u-boot parameters
> > for nfsrooting a lot of boards will no longer work at this point, so if
> > it's not patched to work again without specifying nfs options I think
> > there should at least be a note in the documentation and possibly a
> > "maybe try proto=udp?" console message on failure.
> > 
> > I assume it's not feasable to either wait until the chosen interface's
> > link is ready before trying to mount nfsroot, or retrying TCP-based
> > connections a little bit more aggressively/at all?
> 
> Our goal is to use the same mount logic for both normal user
> space mounts and for NFSROOT (that was the purpose of the patch
> series this particular patch comes from).  It's
> exceptionally difficult to add a special case for retrying TCP
> connections here, as that would change the behavior of user
> space mounts, which often want to fail quickly, and don't need
> to worry about NIC initialization.
> 
> Sounds like the right thing to do is restore the default UDP behavior.  I'll cook up a patch.

Is there some patch available for this now.

There is one more observation (on 2.6.37), when I pass
nfsroot=$(ip):$(rootpath),udp , then it works fine.
If I pass proto=udp then it doesn't work. Is there any difference
between the two methods ?

-- 
regards
Shiraz