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

[Michael Vogt]

Hi,

Julian Edwards discovered a interessting upgrade scenario the other
day. 

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). Now this does no longer work on feisty, the
kernel complains that it can't read the nfs superblock. So on the new
feisty system the user will assume that something broke during the
upgrade.

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 

Input would be appreciated. I personally like option number one, but
this raises the security issue with a open port.

Cheers,
 Michael

P.S. I added this also the https://help.ubuntu.com/community/FeistyUpgrades