[AFS3-std] XCB union decoding (was Re: Encoding IPvN addresses)

[Jeffrey Hutzelman]

--On Friday, February 11, 2011 06:03:49 PM -0500 Jeffrey Altman 
<jaltman@your-file-system.com> wrote:

> The condition of an unknown XCB notification being issued to a cache
> manager would have to be an error.  If XCB is going to support the
> introduction of new notifications, the cache manager must inform the
> file server what the supported notification types are ahead of time via
> the Cache Manager Capabilities.  Otherwise, the file server would not be
> able to send the correct notification form.
>
> In the case that such an error condition were to occur, the cache
> manager would have to treat the receipt of the notification as a generic
> invalidation just as callback breaks are handled today.

Maybe; maybe not.  I think that's an open question, and other reasonable 
designs are possible.  However, the behavior you describe would still 
require use of an extensible union, since otherwise the CM's only option on 
receipt of an unknown XCB notification would be to take no action and 
return RXGEN_SS_UNMARSHAL.

-- Jeff