Subject: Re: mnt_leaf, v_vnlock, VLAYER
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Bill Studenmund <>
List: tech-kern
Date: 12/02/2005 16:28:35
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Fri, Dec 02, 2005 at 10:57:24AM -0500, der Mouse wrote:
> > Wouldn't this problem pretty much go away if, as you suggested, that
> > the current cloud of vnodes (each layer allocates [its] own vnode and
> > tracks that) [were] collapsed into a single entity that could be
> > referenced by all the layers?
> Perhaps, but then you have the problem that a single vnode can refer to
> a whole wack of things, not just one per layer.  Consider, for example,
> a layer which does name remapping a la Eunice - you will often have at
> least two lower-layer entities for one upper-layer entity.  And such a
> thing would be very useful to layer atop, for example, msdosfs.

The simple answer is that we can stack these entities. That's the only way=
that unionfs can work.

I can't say more about Eunice, though, as we don't have anything like it=20
in the tree and all google could tell me was that it seemed like unix=20
services for VMS.

Take care,


Content-Type: application/pgp-signature
Content-Disposition: inline

Version: GnuPG v1.2.3 (NetBSD)