Subject: Re: diffs for UVM/UBC improvements available
To: Bill Studenmund <wrstuden@zembu.com>
From: Chuck Silvers <chuq@chuq.com>
List: tech-kern
Date: 05/22/2001 23:30:32
On Tue, May 22, 2001 at 08:32:29PM -0700, Bill Studenmund wrote:
> On Tue, 22 May 2001, Chuck Silvers wrote:
> 
> > On Tue, May 22, 2001 at 03:00:38PM +0200, Frank van der Linden wrote:
> > > On Tue, May 22, 2001 at 02:38:33AM -0700, Chuck Silvers wrote:
> > > >  - move the vnode lock from struct vnode back into the fs-specific data.
> > > >    the layered filesystems don't have a separate lock for their vnodes,
> > > >    so the lock isn't really a vnode property.
> 
> Hmmm... I should look at the diff. My thought was we'd keep the struct
> vnode *, which would just point into the fs-private data.

actually, here's a reason why this isn't preferable:  it means that
a filesystem which does not use a struct lock to implement VOP_LOCK()
would not work with the layered filesystems.  an example of such a
filesystem would be a cluster filesystem which would need to use a
cluster-wide vnode lock.

-Chuck