pm-hibernate hangs if nfs filesystems mounted

[Patrick Gosling]

Binary package hint: pm-utils

I have a variety of machines which mount user home directories over nfs. When people attempt to hibernate them, the hibernation process hangs horribly.

Having looked at this, the main problem was that pm-hibernate unhooks the network first (in /usr/lib/pm-utils/sleep.d/55NetworkManager) but expects to then be able to call "sync". The latter is clearly never going to work if there are nfs mounted filesystems and no network.

Problem is, you can't do what many people suggest in other related bug-reports, of unmounting the nfs filesystems if they're in active use, with processes having open file descriptors on them. Or rather you _could_ do a forced unmount, but it wouldn't be desirable.

So I wondered why it was necessary to tell NetworkManager to shut down the network. I disabled the 55NetworkManager script, and suddenly hibernation worked, and restarting afterwards worked fine, with no ill effects.

I've only checked this a couple of times so far; and only over periods of up to 30 minutes.

Also, my machines are given static dhcp leases (ie not from a pool), so never change IP address. I'm not entirely convinced that dynamic dhcp allocation should be problematic though; it should surely be no different waking up from hibernation and finding your lease has expired, to just finding your lease has expired ...

I'm wondering what the motivation for the 55NetworkManager sleep.d script is, as I assume it wasn't just added for fun 8-)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Luis Andrés Gonzalez (luisandresgonzalez)]

I have a similar problem, as posted in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/898615.