[systemd-devel] prevent unmount of single partitions on shutdown

[Zbigniew Jędrzejewski-Szmek]

On Wed, Aug 21, 2013 at 05:21:59AM +0200, Stephan Raue wrote:
> Hi,
> 
> i try to port systemd on a own embedded OS which is stored in a
> squashfs file. This file is on a fat partition (later mounted as
> /flash) on the drive.
> 
> In our own initramfs (which dont uses systemd) /flash will be
> mounted and then the Squashfs file as /sysroot. later we do a
> switch_root and start systemd. On shutdown systemd trys now (5
> times) to unmount /flash and times out later with a error message.
> This delays the shutdown/reboot much. Systemd also trys to cleanup
> /dev/loop0. I need to prevent systemd to unmount /flash and clean
> /dev/loop0 (which is the / mount from the squashfs file).
> 
> can i actually prevent this in some way and if nout could i request
> a feature to add a mount option which if avaible prevents systemd
> from unmounting single partitions and cleanup /dev/loopX if its
> still mounted as / ? I need this as mount option or a systemd unit
> file but for fstab based systems it would be usefull as a fstab
> option too (we dont use fstab)
I don't think it's possible currently with fstab. But with
a mount unit, I think
  DefaultDependencies=no
  RequiredBy=-.mount
should work. Have you tried something like that?

Zbyszek