Running a service *just* before unmounting filesystems

[hdegoede@xxxxxxxxxx (Hans de Goede)]

Hi,

On 13-06-18 17:05, Zbigniew JÄ?drzejewski-Szmek wrote:
> On Wed, Jun 13, 2018 at 04:55:27PM +0200, Hans de Goede wrote:
>> Hi,
>>
>> On 12-06-18 19:11, Lennart Poettering wrote:
>>> On Di, 12.06.18 11:33, Hans de Goede (hdegoede at redhat.com) wrote:
>>>> AFAIK the service actually doing the updates is supposed to call
>>>> systemctl reboot --force when it is done, so any targets after
>>>> system-update.target won't get started ?
>>>
>>> True, the service in question could split the reboot call of course,
>>> if it wanted, so that you can plug things in between.
>>
>> Since in this case we want to increment a boot_indeterminate counter
>> to indicate the last boot was not a normal boot, so no clear
>> success status is available I'm fine with the service doing the
>> increment before the updates run.
>>
>> So I was thinking about adding a system-update-pre.target
>> and then in system-update.target add:
>>
>> Wants=system-update-pre.target
>> After=system-update-pre.target
> Yep, that sounds reasonable.

So one more question about this, as discussed in the pull-req,
updates services being linked from system-update.target.wants
now need a "After=system-update-pre.target" in their .service
files. I plan to file bugs against the existing .service
files there for this (*).

Will those service files potentially having
After=system-update-pre.target
on systems with an older systemd which does not have that
target be a problem, or will systemd just ignore this?

Regards,

Hans




*) and in the case of fwupd-offline-update.service also to
add:

DefaultDependencies=false
Requires=sysinit.target
After=sysinit.target

Which it is all missing