[Linux-cluster] Two cluster nodes hold exclusive POSIX lock on the same file

[David Teigland]

On Fri, Oct 30, 2015 at 03:04:34PM +0100, Vladimir Martinek wrote:
> Hello,
> 
> I have a 3 node cluster and fencing agent that takes about 30
> seconds to complete the fencing. In those 30 seconds it is possible
> for two nodes of the cluster to get exclusive POSIX lock on the same
> file.
> 
> Did I miss something here or is this correct behaviour?
> 
> Also, when trying with BSD flock, it works as I would expect - the
> locks are only released after the fencing completes and node 1 is
> confirmed to be fenced.
> 
> Following is output of dlm_tool dump command. Watch for the line
> "gfs2fs purged 1 plocks for 1" - the locks of failed node 1 are
> purged long before the fencing is completed.
> 
> Thank you for any advice.

It works as expected; recovery of posix locks does not need to wait for
fencing to complete.
Dave