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> -----Original Message-----
> From: Greg Freemyer [mailto:freemyer-ml@NorcrossGroup.com]
> Sent: Saturday, August 02, 2003 12:54 AM
> To: opengfs-devel@lists.sourceforge.net
> Subject: RE: [ogfs-dev]Recovery Race conditions
> Does you locking document discuss when persistent locks are used vs.
> non-persistent?
see newest ogfs-memexp, search for "STOMITH" to find discussion of recovery process.
memexp does not call any locks "persistent", but seems to treat "exclusive" mode locks in a way that seems just like "persistent" OpenDLM locks. That is, memexp marks a dead node's exclusive locks in a special way ("expired") so that no other node can use them (with the exception of NOEXP -- see newest ogfs-locking).
>
> This would only apply to non-persistent, and I don't know
> what they are
> used for.
I think non-persistent locks map well to memexp/ogfs "shared" locks. Again, see latest ogfs-memexp.
>
> Obviously I bit off more than I intended when I started this recovery
> doc. I'll try to stick with it through at least a first solid pass.
Thanks, it's been a good forum.
>
> >
> > BTW, I'd like to suggest replacing "ogfs" above, and
> several other places in this list, with "lock module".
>
> Why? If 1.d) is a real issue, I don't know how the lock module can
> handle this with zero support from the ogfs module.
The ogfs module knows basically nothing about coordinating multiple nodes, especially in terms of recovery. For recovery, ogfs just gets a call from the locking module that a journal replay is needed, and once that is done, ogfs calls the locking module so it can proceed with the final steps of recovering "exclusive" (i.e. "persistent) locks. Beyond that, all the smarts are in the locking module, and different modules have different ways of handling this.
-- Ben --
Opinions are mine, not Intel's
>
> Greg
> --
> Greg Freemyer
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