Re: mount.nfs: access denied by server

[Trond Myklebust <trond.myklebust@fys.uio.no>]

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...

Cheers
  Trond