[systemd-devel] Cycle between logind and NetworkManager in case of remote user database

[Andrei Borzenkov]

В Mon, 15 Dec 2014 14:20:45 -0600
Dan Williams <dcbw at redhat.com> пишет:

> On Mon, 2014-12-15 at 20:40 +0300, Andrei Borzenkov wrote:
> > В Mon, 15 Dec 2014 11:34:17 -0600
> > Dan Williams <dcbw at redhat.com> пишет:
> > 
> > > 
> > > On Mon, 2014-12-15 at 16:11 +0100, Lennart Poettering wrote:
> > > > On Sat, 13.12.14 10:09, Andrei Borzenkov (arvidjaar at gmail.com) wrote:
> > > > 
> > > > > NetworkManager sets logind inhibitor lock to monitor for suspend
> > > > > events. So it implicitly requires logind to be present when NM
> > > > > starts.
> > > 
> > > NM doesn't actually require that, it just wants to know about the
> > > signals that logind sends and have a chance to respond to them.  If
> > > logind isn't running, NM shouldn't really care.  But perhaps expectation
> > > is not matching reality in the code.
> > > 
> > > > Any idea what it needs the inhibitor for?
> > > 
> > > To be aware of suspend/resume events of course.  NM may want to
> > > disconnect the network cleanly before suspending, and on resume may need
> > > to clean up network connections and restart certain operations.
> > > 
> > > > > logind is ordered after nss-user-lookup.target. If we have remote
> > > user
> > > > > database, it means that logind depends on network to be up and
> > > running.
> > > > > 
> > > > > If network is provided by NetworkManager we have a loop.
> > > > > 
> > > > > Due to the fact that NetworkManager service itself does not declare
> > > > > dependency on logind, it can be pretty hard to recognize.
> > > > > 
> > > > > Any idea how it can be solved nicely? I can only think of delaying
> > > > > inhibitor logic in NM until logind is started. Not sure what side
> > > > > effects it may have.
> > > > 
> > > > Yeah, I figure if they want to be able to run in early parts of boot
> > > > they should watch logind's bus name and create their inhibitor only
> > > > after it appears.
> > > 
> > > Does logind get D-Bus autolaunched?
> > 
> > Yes.
> > 
> > >                                    NM is just creating a bus proxy for
> > > the logind DBus service, and then attempting to call a D-Bus method on
> > > logind to take an inhibitor.  It doesn't actually care that much about
> > > the result, but NM doesn't pass G_DBUS_CALL_FLAGS_NO_AUTO_START to
> > > prohibit logind from launching.
> > > 
> > > Perhaps NM is requesting logind to start through D-Bus autolaunch, but
> > > since the network isn't up yet logind then fails itself?
> > > 
> > 
> > systemd tries to launch logind service which now waits for services it
> > is ordered After and eventually times out.
> 
> NM patch filed for review by NM dev team:
> 
> https://bugzilla.gnome.org/show_bug.cgi?id=741572
> 

Yes it was reported to fix the problems during system startup. Thank
you!

I wonder if there is any way to delay suspend in race free way.

> Also, I don't think logind should fail if there is no network;

Logind was not even started - systemd waited for required services to
start it and timed out.