While it is possible to disable sysext/confext merging in the main system
with 'systemctl disable', sysext/confext are always merged in the initrd,
both by systemd-{sys,conf}ext-initrd.service and by
systemd-{sys,conf}ext-sysroot.service and especially the latter can be
unexpected. Provide kernel cmdline options systemd.{sys,conf}ext=0 and
rd.systemd.{sys,conf}ext=0 covering all options.
The new services are used to activate system and configuration extensions
for the main system from the initrd, this allows to overcome the limitation
that sysext/confext cannot be used to update the resources which are required
in the earliest boot of the system (before systemd-sysext/systemd-confext
start).
Load global sysext/confext from /.extra/global_{sysext,confext} which
systemd-stub puts there from ESP/loader/credentials/*.{sysext,confext}.raw.
Global extensions are handled the exact same way as per-UKI ones.
File system modules should be something the kernel can autoload
automatically, and according to my testing that works fine, hence let's
drop the explicit deps, in particular as systems usually stick to one fs
for these things, not both.
I inquired bluca about the reason to add it, and didn't remember
anymore, and was fine with me removing this. So let's remove this for
now, should issues arise we can revert this.
In the initrd we want to run as early as possible, before
any of the filesystems are set up, so that users can use
sysexts to customize kernel modules, firmware, etc. But
in the root fs it needs to run after /var/ has been set
up. Split the unit, and have an initrd-specific one that
runs very early.
Vitaly Kuznetsov
Lennart Poettering
Luca Boccassi