[815] in testers
Re: Proper/better (?) fix to VAX afs time skew
daemon@ATHENA.MIT.EDU (daemon@ATHENA.MIT.EDU)
Mon May 21 07:52:58 1990
Date: Mon, 21 May 90 07:52:28 -0400
To: epeisach@MIT.EDU
Cc: testers@MIT.EDU, bug-afs@MIT.EDU
In-Reply-To: Ezra Peisach's message of Sun, 20 May 90 22:23:22 -0400,
From: Richard Basch <probe@MIT.EDU>
From: epeisach@ATHENA.MIT.EDU
Date: Sun, 20 May 90 22:23:22 -0400
. . .
There is one concern I have with my change: When writing to a file, the
Dataversion must change so that flushing it will do something. I have
not verified that the code is proper in that area, but I do appear to be
soring files, so I assume it works. (Not really the right assumption so
it needs to be checked). There is another versionnumber that deals with
mod's, so this fix should be examined with this other aspect in
light....
First, let me state from looking at the patch for about an hour and the
various paths, your patch looks correct, with the possible exception of
the write path, which I was unable to trace... apparently, the write
path involves the callback mechanism, and there at least seems to be
code to detect changes on the server as the callback mechanism updates
the f.Unique field of the cache entry. afs_StoreDCache seems to send
out the data to the server, and I suspect that it receives a callback
after that in order to obtain the new version number. Essentially, it
is the FidCmp() macro that detects changes in the f.Unique field (and
the f.Vnode, f.Volume, and f.Cell fields) and appropriate action is then
taken... checking all this logic may take a few weeks.
-Richard
