[systemd-devel] dev-root.device is not active, results in an umount spree

Lennart Poettering lennart at poettering.net
Mon May 18 05:10:53 PDT 2015


On Mon, 18.05.15 06:41, Martin Pitt (martin.pitt at ubuntu.com) wrote:

> Lennart Poettering [2015-05-17 18:06 +0200]:
> > More specifically, they should follow the second item in the
> > "Execution Environment" section: pre-mount /sys read-only in the
> > container.
> 
> That's the default indeed, but you can configure it otherwise. While
> that might be questionable, it's just one way to exhibit the bugs, as
> Dimitri's plan9 example shows there are other cases where file systems
> aren't on a "real" /dev/ device.

I don't really grok what the problem you are experencing is supposed
to be: note that a device showing up in /proc/self/mountinfo means it
will be set to "tentative" state, and thus will not resolve in an
unmount. What more do you need?

The whole point of the "tentative" state is that devices showing up in
/proc/self/mountinfo but not in /sys are put in it. Are you saying
that does not work?

Generally, dependencies should not be generated depending on
state. Dependencies should be static as much as possible, and
sometimes augmented as we load in more units, but the very clear focus
needs to be to keep them as static as possible. Acting on them should
be dynamic however, and hence our state engines for the units should
be optimized to reflect the unit state as fine-grained as necessary.

I don't understand your patch I must say, but from what I grok it
appears to make deps dynamic, based on state, and that's something I
really don't like.

Lennart

-- 
Lennart Poettering, Red Hat


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