lvm realrootdev group/volume

Hello.

If i am not busy this would be already in form of patch. So first I want to apologize for this not being one.

How about adding new command to the set. This one will set correct /proc/sys/kernel/real_root_dev. It's for use in initrd. Scenario:
initrd
pivot or change root

BTW: And also way of updating /new_root/dev/{mapper,vg_names*}/ entries would be nice.

Or maybe somebody can point me to some mapperfs patches?