Re: getting wedge information (esp. size) in kenrel ?

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Mon, Feb 25, 2008 at 09:39:49AM -0600, Ronald Roskens wrote:
> On Sun, 2008-02-24 at 19:34 +0100, Manuel Bouyer wrote:
> > Hi,
> > right now, the Xen block device backend gets the size information
> > of the backing device with
> > VOP_IOCTL(xbdi->xbdi_vp, DIOCGPART, &dpart, FREAD, 0);
> > but with this the size information is trucated to 32bits. If xbdi_vp points
> > to a wedge device, is there a way to get its 64bit size (and how do I
> > know it's a wedge in the first place) ?
> 
> Hi Maneul,
> 
> I had opened a bug (kern/37370) regarding a xen dom0 directly using
> wedges for the domU's disk devices. You can probably close the bug once
> you decide what to do.
> 
> See the function rf_getdisksize() in sys/dev/raidframe/rf_netbsdkintf.c
> which is what I based my patch off of. Essentially, you need to call
> VOP_IOCTL(..., DIOCGWEDGEINFO, ...) if the DIOCGPART failed.

Ops, thanks for reminding me this one. Would have saved me some time if
I didn't let it root :(

There's one minor issue with your patch, which is I'm not sure it's
correct to call DISKPART() on a dk(4) device. At this point we can use
dkw_devname, which has the complete name of the device.
Also, instead of trying blindly DIOCGPART, we can compare devname against "dk"
to use DIOCGPART or DIOCGWEDGEINFO. isswap() already does it.

-- 
Manuel Bouyer, LIP6, Universite Paris VI.           
Manuel.Bouyer%lip6.fr@localhost
     NetBSD: 26 ans d'experience feront toujours la difference
--