[Bug 211631]: CIFS/SMBFS shares not unmounted before network is shut down

Mathias Gug mathiaz at ubuntu.com
Fri Nov 7 03:51:06 UTC 2008

Hi Reinhard,

On Thu, Nov 06, 2008 at 02:25:48PM +0100, Reinhard Tartler wrote:
> Could someone from the server team please review the following bug:
> https://bugs.launchpad.net/bugs/211631
> it seems that the samba package needs an additional init script to
> unmount volumes before the network connection gets killed. There is a
> script proposed that looks very promising. also the issue looks pretty
> well analysed.

After some discussions with Steve Langasek I left the following

The issue discussed here boils down to the fact that network interfaces
can be brought down *before* network filesystems are unmounted thus
leading to a long timeout.

One option proposed was to move the umountnfs script earlier in the
shutdown sequence. Doing this leads to the possibility that running
processes still have files opened on the network share. This is the
reason why S31umountnfs.sh is run *after* S20sendsigs. Some packages
have their shutdown scripts set too early in the boot sequence. These
should be fix rather then moving the umountnfs script earlier in the
shutdown sequence.

Another option suggested was to use the ifdown.d infrastructure. That
means writing a script that is able to unmount network filesystems
according to the interface been brought down. However the script should
not unmount the remote filesystems when *a* network interface goes down
but rather unmount them when the *corresponding* network interface goes

What *should* be happening in all cases is that the network route is
gone. Trying to send to it will return a no-route-to-host which can be
detected and handled by the kernel. So either the route isn't being torn
out when it should be, and we should fix that; or the cifs driver
doesn't handle no-route-to-host, and we should fix that. Adjusting the
timeouts or moving/adding init scripts shouldn't matter at all.

[1]: https://bugs.launchpad.net/ubuntu/+source/samba/+bug/211631/comments/52

Mathias Gug
Ubuntu Developer  http://www.ubuntu.com

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