I have two devices on my network that provide NFS shares. One is an Icy Box NAS4402-B (running a current version of OpenWrt), the other a home-brew sever running SMS. Both provide NFS4 mounts.
I've got multiple Linux distros installed on my laptop. I mainly use Arch, but have both SalineOS and Salix available as well.
When running Arch, I must unmount the NFS shares before shutting the laptop down. If I fail to do so (happens quite often, since I tend to forget that they're mounted), the laptop will not shut down, it simply hangs at the start of the shutdown. Sometimes I can break out of the hang using CTRL-C, but more often than not, I have to use the power switch.
I suspect that I've not got something correctly set up in systemd (which is now default init for Arch), but I'm having trouble confirming it. What makes me suspicious is if I manually unmount the shares before attempting to shutdown there is no problem. I tried adding the unmount commands to /etc/rc.local.shutdown, but that hasn't helped. It looks as if the hang occurs before rc.local.shutdown is executed, since I get errors from the commands if the shares are not mounted when I shut down, but don't see any sign of the system getting that far if the shares are mounted.
I've tried changing the export commands on both NFS severs, but haven't seen any change. I could try 'soft' mount, but I'm wary of the potential data corruption.
Does anyone have any idea how I could go about tracking down what is holding the shares open and preventing the shutdown, or does anyone know enough about systemd to know what should be used setting it up for NFS?
I've tried asking questions in the Arch forum and mailing lists, but so far have only got a couple of people reporting similar problems, no suggested solutions..... I should also note that the problem only occurs under Arch - both SalineOS and Salix will shutdown cleanly without manually unmounting the NFS shares prior to shutting the system down.