[AFS3-std] File Server/Cache Manager Extended Status Information

[Jeffrey Hutzelman]

--On Monday, April 07, 2008 05:44:38 PM -0400 Matt Benjamin 
<matt@linuxbox.com> wrote:

>| The existing model works today but suffers from the failure to know that
>| the reason a callback was received was because the lock was dropped or
>| because a Store occurred etc.
>
> I believe there is a race between A (who received EWOULDBLOCK, and has
> decided to re-try) and B, who requests an overlapping lock, in the
> interval between C's release of the contended lock (3) and A's
> re-execution of its lock request (1).

I know of no race condition in the current locking model.  In the situation 
you describe, one of A or B will get EWOULDBLOCK, because the fileserver 
will not allow both overlapping conflicting locks to succeed.  There 
certainly is an unfairness, which is not the same thing.

-- Jeff