[systemd-devel] Possible bug when a dummy service declares After= and/or Conflicts= a .mount unit?

[Michael Biebl]

2015-03-06 17:09 GMT+01:00 Didier Roche <didrocks at ubuntu.com>:
> Le 06/03/2015 16:17, Michael Biebl a écrit :
>>
>> 2015-03-06 11:20 GMT+01:00 Didier Roche <didrocks at ubuntu.com>:
>>>
>>> It seems like tmp.mount unit was skipped as nothing declared any explicit
>>> dependency against it. What seems to confirm this is that if I add any
>>> enabled foo.service which declares After=tmp.mount, or if I add the
>>> After=
>>> statement to systemd-timesync.service, then I get tmp.mount reliably to
>>> start (and it was installed as the journal shows up). Does it make sense?
>>
>> I do have several units which have PrivateTmp=true (cups.service,
>> timesyncd) which *are* started during boot, yet tmp.mount is not being
>> activated. Inspecting the units via systemctl shows e.g.
>>
>> $ systemctl show cups.service -p After -p Requires
>> Requires=basic.target cups.socket -.mount tmp.mount
>> After=cups.socket -.mount system.slice tmp.mount basic.target
>> cups.path systemd-journald.socket
>>
>> Why is tmp.mount then not reliably activated during boot here?
>>
> Right, that's the question, my feeling is that PrivateTmp=true isn't mapped
> right away as corresponding to tmp.mount at boot time, and so, as nothing
> refers to tmp.mount explicitly, systemd doesn't take that unit into account.
> Then, it's present later (after boot time) and that's why starting or
> restarting an unit with PrivateTmp=true would then pull it.
>
> That would also explains why if you enable a service like foo.service
> declaring a relationship to tmp.mount (like After=tmp.mount), this one is
> reliably seen at boot time from systemd, and thus, reliably started, even
> when booting by any units declaring PrivateTmp=true.
> Would that be the bug?

Fwiw, I can reproduce this particular bug under Fedora:
Just remove the
/usr/lib/systemd/system/local-fs.target.wants/tmp.mount symlink,
reboot, login on tty2, notice how tmp.mount is not active (mounted),
although there are various services active with PrivateTmp=true.



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