3.10-rc3 NFSv3 mount issues

["Jim Schutt" <jaschut@sandia.gov>]

Hi,

I've been trying to test 3.10-rc3 on some diskless clients, and found
that I can no longer mount my root file system via NFSv3.

I poked around looking at NFS changes for 3.10, and found these two
commits:

 d497ab9751 "NFSv3: match sec= flavor against server list"
 4580a92d44 "NFS: Use server-recommended security flavor by default (NFSv3)"

If I revert both of these commits from 3.10-rc3, then my diskless
client can mount its root file system.

The busybox mount command fails like this, when using 3.10-rc3:

/ # mount  -t nfs -o ro,nolock,vers=3,proto=tcp 172.17.0.122:/gmi/images/jaschut/ceph.toss-2x /mnt
mount: mounting 172.17.0.122:/gmi/images/jaschut/ceph.toss-2x on /mnt failed: Invalid argument

The commit messages for both these commits seem to say that mounting
with the "sys=sec" option should work, but unfortunately, my busybox doesn't
seem to understand the "sec=" mount option:

/ # mount  -t nfs -o ro,nolock,vers=3,proto=tcp,sec=sys 172.17.0.122:/gmi/images/jaschut/ceph.toss-2x /mnt
mount: invalid number 'sys'

My NFS server is based on RHEL6, and is not using any "sec=" option
in its export for this file system.  I did try exporting with "sec=sys",
but it didn't seem to make any difference either.

So far, this seems like a regression to me ....
Any ideas what I might be doing wrong?  How can I
help make this work again?

Thanks -- Jim