Subject: Re: newfs: determining file system parameters
To: Bill Studenmund <wrstuden@netbsd.org>
From: Christian Limpach <chris@pin.lu>
List: tech-kern
Date: 10/18/2003 00:19:50
On Fri, 17 Oct 2003 14:36:00 -0700 Bill Studenmund <wrstuden@netbsd.org> wrote:

> Think about wedges. In a wedges-based world, we just have partitions.
> This ioctl will be perfect for that. Adding it now makes it easier to 
> go to a wedges scenario.
> Since there's more to all of this than just size, the ioctl has use. It
> in fact is needed in the long run. :-)

yes, but do you know right now everything you ever want to store in the
disklabel or in the partition's metadata storage[1].  Assuming this is not
limited to the disklabel format forever (and on some ports it isn't even
now), the ioctl should handle arbitrary data, probably some kind of tagged
data structure where newfs can lookup and modify the values it needs.  The
data structure would also have to reflect which values can be stored in the
partition's metadata storage.

It would be nice to have such an ioctl for the problem at hand.  I think
that adding the ioctl now is not a good idea:  with an ioctl which only
handles specific partition information (be it only size or even struct
partition), we'll have backward compatibility issues in the future. 
Afterall, there are other simple solutions for the problem at hand.

[1] i.e. wherever you store the fs-type and cpg/sps in wedge world

-- 
Christian Limpach <chris@pin.lu>