Comment 5 for bug 1299225

I can suggest the outline of a fix, but I don't have enough system knowledge to provide the actual code.

What's needed is a script in one of the /etc/rc.d files that checks all mounted filesystems to see if they are remote. If a filesystem is remote, then it is forcibly unmounted. This script should be positioned so that it is executed before the networks are shut down and before the general unmounting.

I'm not sure about the best criterion for choosing the filesystems to be unmounted in this way. It might be better to see what device the root filesystem is on and unmount everything but the ones on that device.