linux-kernel - Re: mount.nfs: access denied by server

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Date:	Fri, 21 Aug 2009 13:50:52 -0400
From:	Chuck Lever <Chuck.Lever@...cle.com>
To:	Wu Fengguang <fengguang.wu@...el.com>
Cc:	Trond Myklebust <trond.myklebust@....uio.no>,
	NFS list <linux-nfs@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: mount.nfs: access denied by server


On Aug 20, 2009, at 10:36 PM, Trond Myklebust wrote:

> On Fri, 2009-08-21 at 09:27 +0800, Wu Fengguang wrote:
>> On Thu, Aug 20, 2009 at 09:02:29PM +0800, Trond Myklebust wrote:
>>> On Thu, 2009-08-20 at 15:13 +0800, Wu Fengguang wrote:
>>>> Hi,
>>>>
>>>> After upgrading NFS client kernel to latest linux-next, NFS mount
>>>> failed:
>>>>
>>>>        # mount -t nfs pxe:/cc /cc
>>>>        mount.nfs: access denied by server while mounting pxe:/cc
>>>>
>>>>        # uname -a
>>>>        Linux hp 2.6.31-rc6-next-20090818 #61 SMP Thu Aug 20  
>>>> 14:46:10 CST 2009 x86_64 GNU/Linux
>>>>
>>>> However server log says OK:
>>>>
>>>>        Aug 20 15:02:09 wu-t61 mountd[4599]: authenticated mount  
>>>> request from 192.168.11.6:973 for /cc (/cc)
>>>>        Aug 20 15:02:09 wu-t61 mountd[4599]: authenticated unmount  
>>>> request from 192.168.11.6:974 for /cc (/cc)
>>>>
>>>> However-2: nfsroot can be mounted at boot time. Server kernel has  
>>>> always been 2.6.30.
>>>>
>>>> Any ideas?
>>>>
>>>> Thanks,
>>>> Fengguang
>>>
>>> Can you try again after enabling mount debugging on the NFS client?
>>>
>>> echo 512 > /proc/sys/sunrpc/nfs_debug
>>
>> I used 1024 and found the mount failed here in nfs_walk_authlist():
>>
>>        dfprintk(MOUNT, "NFS: server does not support requested auth  
>> flavor\ n");
>>        nfs_umount(request);
>
> Thanks Fengguang!
>
> Chuck, this looks like one of yours. Could it be that you are hitting
> the same Linux knfsd bug that Tom Haynes saw with a Solaris client?
> AFAICR, the problem was that existing nfs servers do not set a default
> auth flavour, and so you just have to try with auth_sys and see if it
> succeeds...

With 1024 set, the mount client's XDR routines should have listed the  
server's flavors, if any, in the system log.  Should be something like  
"NFS: received 0 auth flavors" if the server didn't return any.  Can  
you confirm that?

I'll try to post a fix later today.

--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com



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