[systemd-devel] Why did you set MountFlags=slave in systemd-udevd.service.in

[Lennart Poettering]

On Fr, 02.03.18 10:22, Hongzhi, Song (hongzhi.song at windriver.com) wrote:

> On 2018年03月01日 17:50, Lennart Poettering wrote:
> > On Do, 01.03.18 14:44, Hongzhi, Song (hongzhi.song at windriver.com) wrote:
> > 
> > > Thank you very much. It dose work.
> > > 
> > > Would you tell me that how the '--no-block' works,
> > "systemd-mount" talks to systemd (i.e. PID 1) to issue mount/automount
> > operations. By default it will do so synchronously, thus blocking
> > until the mount is established. If you specify "--no-block" then you
> > turn off this synchronous behaviour, and instead request asynchronous
> > behaviour, where the rule will just request the operation to be
> > executed, but won't wait for it to finish. When you invoke
> > "systemd-mount" from a udev rule then using "--no-block" is a
> > necessity to avoid a deadlock. That's because PID 1 won't operate on a
> > device to mount before udev reported it to be fully availabled and
> > probed.
> Do you mean that udev doesn't report device to be fully availabled
> and probed until systemd-mount returns?

Yes. All programs configured in udev rules files need to finish before
udev reports the device to its clients to be fullyprobed and ready.

Lennart

-- 
Lennart Poettering, Red Hat