Re: mount.nfs: access denied by server

[Chuck Lever]

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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