[OpenAFS] GiveUpAllCallBacks callers

[omalleys@msu.edu]

> We're not proposing making a change to the client which causes it to  
> start triggering these bugs - I think this is just a distraction. We  
> know that people should upgrade - we don't make stable releases for  
> the good of our health. But the fact is that for various reasons,  
> people don't upgrade their servers nearly as often as they should.

The server needs to safely handle/refuse all unsupported client  
requests as they could be malicious.

There was a "feature request" a number of years ago to do "client  
versioning" so the administrator of the cell could give warnings, or  
refuse connections based on the client version/platform (too new, too  
old or buggy version) to help prevent this situation. Logs would be  
both on the client and the server. The client owner would have some  
warning and see something in their logs and the AFS administrator  
would have logs/usage stats and could more easily track down people to  
tell them to upgrade their systems and at least verify "mission  
critical" systems are not going to be adversely affected.

One reason why no one wants to upgrade. If you upgrade, you break the  
1.2 version of the client which just happens to be what the now VP of  
the company used to write a web interface client and no one has  
bothered to upgrade it. You don't even know since that is "top-secret"  
information. Or you hear "oh yeah yeah it is next on the agenda to  
upgrade" for 2 years or maybe even a "oh yeah we did it." then after  
the upgrade you get "oh you meant -that- machine? We don't touch that  
at all". You need a procedure and stats to back you up or else you  
might as well be in prison picking up bars of soap in the shower.