Re: [gentoo-user] udev + /usr

[Alan McKinnon]

On Mon, 12 Sep 2011 17:33:34 +0200
Michael Schreckenbauer <grimlog@×××.de> wrote:

> Every udev version works this way.
> Fixing udev to continue working with separate /usr is far from
> trivial imo. Changing some paths is not the way to go for sure.
> First of all, udev has to distinguish between "device not present"
> and "script error of some kind". Failing scripts have to be queued
> somehow for later execution. If a script keeps failing, it has to be
> removed from that queue, with a message to syslog or something like
> that. If udev needs a script in /usr/* to mount /usr then there's a
> chicken-egg-problem, which could be hard to solve (if possible at all
> without moving things from /usr/ to /). Note, that I am wild guessing
> here, I did not study the udev sources or any related script/rule :)

To expand on that:

udev running at early boot time and udev running later with a full
userspace mounted are very different things. udev should be able to
differentiate between these two phases and modify it's behaviour. Put
another way:

The thing that lays the foundation for the full userspace to be in
place *CANNOT* assume the existence of the full userspace. That's like
the wall assuming the roof must exist.

Furthermore, it's not at all a case that /usr must be mounted - that's
just an interesting artifact, and expression of where stuff is. The
correct description is more like "the script that udev launches must be
available to udev *when* udev launches it". I think concentrating on
the problem expressed in this wise would open the door to better
solutions.

I do like the idea of a phase 1 and phase 2 approach by udev - early
boot and full userspace running.

-- 
Alan McKinnnon
alan.mckinnon@×××××.com