Re: [gentoo-user] udev-197 moves from /usr/lib to /lib

[Canek Peláez Valdés]

On Fri, Jan 11, 2013 at 8:04 AM, walt <w41ter@×××××.com> wrote:
> This seems to me like very happy news indeed, but I'm interested in contrary
> opinions.  There's a recent thread discussing how udev-197 breaks lvm2, but
> that's a trivial fix once you know about it.
>
> The problem is caused because many apps including lvm2 install their udev
> config scripts in /usr/lib/udev/rules.d/ (where they never belonged in the
> first place IMO) and they should instead now go in /lib/udev/rules.d/.
> All you need to do is to re-emerge all of those packages *after* installing
> udev-197 and the config scripts will go in the correct place.
>
> You should do this before rebooting the machine because lvm2 won't work until
> its udev scripts are in the correct directory.
>
> Doesn't this seem to fix the problem with booting a separate /usr partition?

No, because the problem has never been in udev (nor systemd, for that
matter). It fixes how *Gentoo* packages udev; probably the devs read
the following comment from Lennart (note it was written almost a month
ago):

https://plus.google.com/u/0/115547683951727699051/posts/jcCjMct3SJ3

Certainly, <=sys-fs/udev-171-r9 didn't use --with-rootprefix in the ebuilds.

That's the reason Greg and many others were so dubious about eudev:
one of the primary reasons for the fork to exist is supposedly to
support a separate /usr without an initramfs... but that has *always*
been supported by udev. And systemd, for that matter. systemd/udev
prints a warning if it doesn't finds /usr at early boot, but both work
in such configuration without any problem (if configured properly by
the distribution, which apparently in Gentoo's case wasn't true).

So, no, it doesn't "fix" the separate /usr problem, because that has
never been a problem of udev nor systemd. And it's not going to be
"fixed" by eudev either, for the same reason.

But it fixes how udev it's packaged in Gentoo, which is very good
news. I haven't upgraded, since I need systemd-197 also (which wasn't
yet in the tree yesterday), and I don't use LVM, but I'm wondering if
the LVM problem happens when you use an initramfs. I'm guessing it
doesn't, since udev should read rules from /lib/udev/rules.d AND
/usr/lib/udev/rules.d.

Regards.
-- 
Canek Peláez Valdés
Posgrado en Ciencia e Ingeniería de la Computación
Universidad Nacional Autónoma de México