[arch-general] Problem with NFS on shutdown

[Paul Marwick]

I've got two machines in my local network that provide NFS shares. One 
is an old Raidsonic NAS (running a current version of OpenWRT), the 
other a dedicated server running Slackware). I normally mount the shares 
manually (the machine that is giving me a problem is a laptop, so its 
often not connected to my own network).

The problem comes when I try to shut the laptop down (or restart it). 
Unless I've manually unmounted the NFS shares, the machine will hang and 
fail to shut down. In some instances, I've been able to use CTRL-C to 
break out of the stall, but frequently, I can only turn the machine off, 
which is not exactly ideal.

I've been playing with the nfs exports, currently have the following:

/mnt/sda2/stor 
192.168.1.0/255.255.255.0(rw,sync,no_wdelay,nohide,no_root_squash) (this 
is on the Raidsonic)

and

/mnt/sda2/stor 
192.168.1.0/255.255.255.0(rw,sync,no_wdelay,nohide,no_root_squash) on 
the Slackware server.

The problem is specific to Arch - I've got two other distros installed 
on the laptop (though Arch is my usual OS). From SalineOS or Salix, the 
laptop will shut down or restart without having to manually unmount the 
NFS shares prior to shutdown.

I suspect I've not got something set up correctly in systemd, but I'm 
currently at a loss to work out what. If I manually unmount the shares 
before shutdown, there is no problem. I've also tried adding the unmount 
to /etc/rc.local.shutdown, but that doesn't work - the system still 
hangs during shutdown. I'm sure that rc.local.shutdown is being executed 
- if I shut down without the shares mounted, I can see messages that 
they are not mounted.

I'm not sure if I should be looking at the NFS export parameters on the 
hosts, or systemd on the laptop, though I've tried some variations on 
the exports without changing the behaviour.

Does anyone know what I should be looking at to solve this?

Paul.