Subject: Re: mount_mfs (with mount_null) won't reclaim space
To: Bill Studenmund <wrstuden@wasabisystems.com>
From: enami tsugutomo <enami@sm.sony.co.jp>
List: tech-kern
Date: 03/18/2002 10:01:08
Bill Studenmund <wrstuden@wasabisystems.com> writes:

> On Sun, 17 Mar 2002, enami tsugutomo wrote:
> 
> > > I'm confused. How does the layer cache keep the underlying close routine
> > > from being called?
> >
> > vcount() sum up all references of aliased vnode across all filesystems.
> 
> Ok. But last time I worked on this code, we did not add layer vnodes to
> the alias lists. So how is this a problem? Only the lower vnode is in the
> alias list.

Assume that the lower vnode is ref.'ed in the layer filesystem cache.

And think the case that someone open the lower vnode in the lower
filesystem directly.  When spec_close is called, it notices someone
else (== layerfs cache) refering it.

enami.