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Re: wedge like devices and newfs

On Fri, May 29, 2009 at 11:09:59AM +0200, Adam Hamsik wrote:
> Hi folks,
> During my work on LVM and ZFS I have found that for historical reasons I 
> need to
> provide disklables on Logical volumes aka zvols on ZFS. I have found  
> that problem
> is mostly in newfs because it uses DIOCGDINFO to get info about disks.

If DIOCGDINFO fails, newfs (and other tools using getdiskinfo()) will use
DIOCGWEDGEINFO.  Maybe having zvols should handle DIOCGWEDGEINFO ?

> I 
> have written
> patch against newfs and kernel disk drivers which changes this  
> behaviour. With my patch
> newfs uses DIOCGDISKINFO and DIOCGWEDGEINFO ioctls to get information  
> about disk/volume
> size.
>  DIOCGDISKINFO is proplib based ioctl which returns dictionary  
> defined in disk.h with
> disk and disk geometry info. DIOCGWEDGEINFO is ioctl for wedge like  
> devices(Logical volumes,
> zvols, dks), other disk devices should still support old disklabel  
> ioctls.

Why is a new ioctl needed ? I can't see what it does which DIOCGDINFO
and DIOCGWEDGEINFO aren't already doing.

Manuel Bouyer, LIP6, Universite Paris VI.  
     NetBSD: 26 ans d'experience feront toujours la difference

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