Re: Adding an ioctl to check for disklabel existence

[mlelstv%serpens.de@localhost (Michael van Elst)]

martin%duskware.de@localhost (Martin Husemann) writes:

>So far all good. But there is a catch: some architectures have native
>ways to store their partitions and no real userland support for those schemes.

Some drivers may also have their own idea about what disklabels
are, in particular cd(4). I wouldn't change anything here, in
particular not add new functionality. There is already too much
magic.

If we really need to distinguish between read and faked labels we
could tag the faked labels. There are unused words, even spare
ones that could hold flags or magic numbers. Reading a label
from disk would then need to verify and strip such information.

The real problem however is then to write a label. Just writing a
normal label that would override the faked label after a reboot
might be confusing when native OS and NetBSD don't agree in their
partitioning scheme.

It might be simpler to just let writing a disklabel fail when a
faked one is used.  Then userland doesn't have to be aware of the
difference, just handle the error.

-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."