I can't imagine there isn't a simple strategy to solve this issue of stale nfs handles preventing a machine from shutting down normally, but I'm not sure what that would be. It's pretty annoying to have to force a reboot just because a wifi connection dropped out at some point while watching endless 'waiting for nfsmount' messages.
What are your mount options?
You should experiment with "
hard,intr", or "
soft" (with "
timeo"), and possibly "
retrans" depending on your client options. Using TCP instead of UDP may also help. The default is usually "
Using "soft" is usually advised against, it can result in written data being lost. It's safe to use as read-only.
On latter linux kernels (2.6.25) NFS clients "intr" is deprecated, sigkill should just work. "
umount -f" and "
umount -l" can help.