Re: ataraid(4) and VOP_OPENing the same block device

[Adam Hamsik <haaaad%gmail.com@localhost>]

On Sep,Saturday 13 2008, at 2:26 AM, Thor Lancelot Simon wrote:

> On Fri, Sep 12, 2008 at 02:51:27PM -0700, Bill Stouder-Studenmund  
> wrote:
> > On Fri, Sep 12, 2008 at 05:09:52AM +0200, Quentin Garnier wrote:
> > > IIUC, the controller allows you to slice disks:  e.g., take two  
> > > halves
> > > out of each, build a RAID1 with one set, and a RAID0 with the  
> > > other.  In
> > > this case both disks belong to each array.
> >
> > Then the right thing to do is somehow export those slices. It makes  
> > sense
> > that different slices can be in different RAIDS, but any given slice
> > should be in only one.
>
> Yes.  What concerns me is that I'd thought Elad had added code to the
> security policy which would in fact make it impossible to use one  
> slice
> twice like this -- I'm not sure why what Juan is doing now works.


In device-mapper I use almost the same approach like Juan in ataraid  
code.
I open physical device once and then I'm using this device for multiple
virtual devices (Logical volumes in lvm) and it works. I'm not sure if  
is
possible to make device-mapper to work in other way.

Regards

Adam.