[AFS3-std] RxOSD claim on 2 structure members

[Steve Simmons]

This note is not intended to respond to anyone in particular.

People grab numbers and bytes from 'unused' lists all the time.  
Sometimes it works out. Sometimes it doesn't, and there needs to be a  
compromise when the software moves from private usage to the broader  
world. It happens with port numbers a lot, and I believe at least one  
author on this list has encountered it. If we know of two groups that  
are using those fields (and one of them might be us at Umich), then we  
need to publicize as best we can and look for a co-operative solution.  
That fact that other as-yet-unknown groups might be using them as well  
is unfortunate, but that's what happens when you make private hacks:  
sometimes the broader world doesn't do things that play nice with your  
hacks.

But refusing to do something with a given field because someone  
somewhere *might* be using it is just silly. With that kind of logic,  
we'd have to avoid ever changing because the change might be  
incompatible with someone else's change.

Let's have the groups we know of come forward, and lets put out a  
reasonable number of public requests for others as-yet-unknown to do  
so. If someone is hacking the source code and protocols at that level  
and is not on *any* of the afs lists, well, they lose.

And for the record, yes, we used one of those "unused" fields  
ourselves for the shadow work. But when you get right down to it, all  
we need it one bit. We've discussed ways to do shadows without using  
that bit, and if we have to, we have to. I will note it'll be a  
helluva lot harder without that bit. I for one don't want to forestall  
legitimized use of that field/bit on the off chance that someone,  
somewhere might be using it.

Steve