Ubuntu
wpasupplicant package

  1. Bug #211631
  2. Comment #76

Comment 76 for bug 211631

Revision history for this message
Thierry Carrez (ttx) wrote : Re: CIFS/SMBFS shares not unmounted before network is shut down

Quick status update/summary on this bug, because this thread is long and tends to discourage people that could solve it.

The bug occurs on shutdown if you mount a CIFS share (using mount or /etc/fstab). In some cases, S31umountnfs.sh tries to unmount the network file system *after* the network has been brought down. CIFS doesn't handle so well having the network pulled out from under it, so it stalls the shutdown process for some time, but the shutdown finally succeeds.

The most common case appears to be those using NetworkManager to handle the network interface (NetworkManager gets killed by S20sendsigs, before S31umountnfs.sh). If you are not using NetworkManager at all (and have your network defined in /etc/network/interfaces), the unmount will succeed. That's why this bug doesn't really affect Ubuntu Server systems. Also I would argue that you should not mount things system-wide while having your network up/down at Gnome session start (think wireless). Nautilus-based mounts seem like a better idea in that case.

It's *not* simple to fix. There are lots of workarounds which will solve the problem for your use case, but which will also break it for other folks. The fact that workaround X solves the issue for you doesn't make it a proper update that can be applied to all other Ubuntu systems. Cutting the network filesystem before S20sendsigs for example may result in data corruption, which is arguably worse than an annoying delay at shutdown.

The best way of solving this is to have CIFS (probably in kernel) better support having the network pulled out from under it. I haven't really found how we could do that, but I'll try to invite some CIFS specialists here. Another way could be to exclude NetworkManager from S20sendsigs and kill it properly at ~S35... constructive, technical comments welcome.

It's true that the way Launchpad works doesn't help us in solving this kind of in-between-packages bugs (and most distributions won't be better than us). But bitching about it just makes developers turn to easier (and more rewarding) bugs to fix.