[OpenAFS] File locking

chas williams - CONTRACTOR chas@cmf.nrl.navy.mil
Thu, 17 Jul 2014 11:50:50 -0400

On Thu, 17 Jul 2014 10:07:07 -0400
Todd Lewis <Todd_Lewis@unc.edu> wrote:

> Was there some change in file locking semantics that would make sense of 
> this? Does this application tickle a corner case error in openafs's file 
> locking, or does more rigorous lock handling in the newer client expose a 
> bug in the application? I have tried to replicate the failure with a very 
> simple C program with no success, but that mostly indicates I'm not sure 
> what I'm testing for.

I noticed that you are opening the file read only, does the file you are
locking reside on a read only volume?  I know there were some changes in
commit 0fc27471e7da0c5de4addcdec1bfbca5208072cc related to this.

commit 0fc27471e7da0c5de4addcdec1bfbca5208072cc
Author: Andrew Deason <adeason@sinenomine.net>
Date:   Tue Oct 2 14:38:20 2012 -0500

    afs: Avoid tracking file locks for RO volumes
    Advisory file locks for RO volumes don't make a lot of sense, since
    there are no possible writes to worry about. The fileserver already
    does not track these, so don't even bother processing them in the
    Change-Id: Ie2a20d2f7af67799cfb8d30e72aa3e52a1ecc2d5
    Reviewed-on: http://gerrit.openafs.org/8197
    Tested-by: BuildBot <buildbot@rampaginggeek.com>
    Reviewed-by: Derrick Brashear <shadow@your-file-system.com>