udev-181 is being unmasked on 2012-03-19.
This news item is to inform you that once you upgrade to a version of udev >=181, if you have /usr on a separate partition, you must boot your system with an initramfs which pre-mounts /usr.
An initramfs which does this is created by
=sys-kernel/genkernel-3.4.25.1 or
=sys-kernel/dracut-017-r1. If you do not want to use these tools, besure any initramfs you create pre-mounts /usr.
Also, if you are using OpenRC, you must upgrade to >= openrc-0.9.9.
For more information on why this has been done, see the following URL: http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken
Смысл приблизительно в следующем: в генте размаскировали udev-181 и предупреждают, что в нём убрана возможность работы с /usr на отдельном разделе. В качестве костыля предлагают использовать initramfs.
HATE!!!