Hi Jeff, ----- "Jeffrey Hutzelman" <[email protected]> wrote:
> --On Thursday, July 23, 2009 06:43:35 PM -0400 "Matt W. Benjamin" > <[email protected]> wrote: > > I see no problem with you being able to negotiate different semantics > for > yourself. However, unless you are somehow privileged, you must not be > able > to negotiate different semantics for _me_. We can argue at some point > > about exactly what that means, but at a minimum, I think it means > things > like... > > - You must not be able to force mandatory locking on me, unless you > are > privileged in some way (for example, by being allowed to set some > access > right or other property of the file). Similar policy problem, yes. > > - You must not be able to decide that, when you write a file, a > callback > to me is broken asynchronously, such that another RPC made on that > file > by me or by a client with whom I am cooperating begins before I > have > been notified that you changed the file. I get that. See action items. > > Further, there must be some common set of semantics where are > guaranteed to > be implemented by every fileserver and every client. Yes. As a number of folks have mentioned, it would be valuable to formalize those semantics as applied to files (the "file semantics of AFS3") better than we have, up to now. I think that's a much smaller problem than "formalize the entire AFS protocol." > > Further still, there are some things which are basic properties of the > > protocol and are not open to negotiation. I believe the one-to-one > relation between (FID,DV) and bit strings is one of these, as is the > one-to-one relation between FIDs and files. I should mention that Tom a couple of times has mentioned the idea of generalizing FID. In one conversation (summarized with permission), also, Tom and I worked on a concept we called 'range DV', aimed at allowing disjoint ranges of a logically contiguous bytestream to be coordinated by different fileservers. Taken together, those concepts might add up to a FID with a vector of (Range,DV)s, or something similar. > > -- Jeff -- Matt Benjamin The Linux Box 206 South Fifth Ave. Suite 150 Ann Arbor, MI 48104 http://linuxbox.com tel. 734-761-4689 fax. 734-769-8938 cel. 734-216-5309 _______________________________________________ OpenAFS-devel mailing list [email protected] https://lists.openafs.org/mailman/listinfo/openafs-devel
