edgy->feisty upgrades for people with nfs mounts and without nfs-common

[Bryce Harrington]

On Fri, Mar 16, 2007 at 10:47:05PM +0100, Reinhard Tartler wrote:
> Michael Vogt <michael.vogt at ubuntu.com> writes:
> 
> > On a stock edgy system without portmap or nfs-common it is possible to
> > nfs mount a directory (also it takes some time for the kernel to
> > timeout on portmap). 
> 
> There are other Operating System which can mount NFS without a
> portmapper (OpenBSD). They don't support locking, but mounting
> works. Why isn't this possible with ubutnu? (#92926)

In NFSv4, portmapper is no longer required, so in the future I imagine
this won't be an issue.

> > Now this does no longer work on feisty, the kernel complains that it
> > can't read the nfs superblock.
> 
> What is an "nfs superblock"?

I don't know the details, but basically it's a grouping of files by
{server,protocol,FSID}

> > I would like to ask for opinions how we should deal with this
> > situation in general and in the release-upgrader in particular. I see
> > the following options if a nfs mount is detected in /etc/fstab:
> >
> > 1. automatically install nfs-common (opens a port)
> > 2. ask the user if he wants to install nfs-common (brings up a
> >    additional question during the upgrade)
> > 3. use some sort of notification (post-upgrade hook) to inform the
> >    user 
> > 4. just do nothing and assume people who can do nfs mounts can deal
> >    with the situation 

I ran into this same issue myself.  Unfortunately the error message it
gives really doesn't provide much illumination into the issue or how to
fix it, so option #4 would probably lead to excessive support requests.
#2 seems like the safest approach; for most ordinary issues that don't
use nfs, they'd never be bothered by the question, but for users who do
have nfs installed, they probably wouldn't be shocked to have a question
about nfs during the upgrade.  ;-)
 
Bryce