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

[Stephan Raue]

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)

thanks

Stephan