Subject: Re: mount_mfs (with mount_null) won't reclaim space
To: enami tsugutomo <enami@sm.sony.co.jp>
From: Jeremy C. Reed <reed@reedmedia.net>
List: tech-kern
Date: 03/15/2002 16:17:15
On 11 Mar 2002, enami tsugutomo wrote:

> "Jeremy C. Reed" <reed@reedmedia.net> writes:
>
> > Has anyone noticed problems or had success with mount_null on mount_mfs?
>
> This is a known problem of nullfs (or layerfs) cache.  This occurs
> since layerfs cache keeps reference to underlying vnode.  Reclaiming
> the space is defered until top vnode is recycled.
>
> There is an incorrect work around in PR#15555.  No real fix yet.  Some
> recent discuss with Bill Stuldenmund and me will be found in
> source-changes.

Thanks for the info. I read this discussion, but it is a little beyond me.

I see your workround is for -current. It (the patches) doesn't work with
1.5.3_ALPHA (due to "`vp' undeclared" and new getpages and putpages
methods).

Would it be okay to apply all these miscfs/genfs/ changes from -current in
my 1.5.3_ALPHA? (I can manually do this, but I wonder if it will cause
problems.)

Or is this something that can be officially added to netbsd-1-5?

Or can someone provide a patch to workaround the nullfs not reclaiming
free space problem for 1.5.3_ALPHA?

Thanks,

   Jeremy C. Reed
   http://www.reedmedia.net/