Re: UVM/genfs review

[Juergen Hannken-Illjes <hannken%eis.cs.tu-bs.de@localhost>]

On Thu, Jan 08, 2009 at 08:01:56PM +0100, Joerg Sonnenberger wrote:
> Hi all,
> given the state of netbsd-5, I would like to get the WAPBL patch
> http://mail-index.netbsd.org/current-users/2008/10/31/msg005591.html
> into HEAD and pull it up. For that I would really like to have review
> from someone who understand UVM and/or genfs. The patch is likely to
> break persistent snapshots with fss(4), but I don't think it will break
> non-persistent ones (e.g. as used for backups).
> 
> Joerg

Just for the records, still strong objection from me.  As I told you before
this would bring back a deadlock (see Rev. 1.12 of genfs_io.c).  We have
to take the wapbl LOCK before we lock pages.  Therefore it will break
ALL file system internal snapshots, persistent or not.

-- 
Juergen Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig 
(Germany)