[Cluster-devel] Re: [PATCH 2/2] dlm: Add down/up_write_non_owner to keep lockdep happy

[David Teigland <teigland@redhat.com>]

On Thu, Nov 12, 2009 at 05:24:12PM +0000, Steven Whitehouse wrote:
> > > Nov 12 15:10:01 chywoon kernel: [ INFO: possible recursive locking
> > > detected ]
> > 
> > That recursive locking trace is something different.  up_write_non_owner()
> > addresses this trace, which as you say, is from doing the down and up from
> > different threads (which is the intention):
> > 
> I don't think it is different, the traces differ due to the ordering of
> running of dlm_recoverd and mount.gfs2,

I explained the "recursive locking" warning back in Sep:

 > I've not looked at how to remove this "recursive" message.  What
 > happens is that mount calls dlm_new_lockspace() which returns with
 > in_recovery locked.  mount then makes a lock request which blocks on
 > in_recovery (as expected) until the dlm_recoverd thread completes
 > recovery and releases the in_recovery lock (triggering the unlock
 > balance) to allow locking activity.

It doesn't appear to me that up_write_non_owner() would suppress that.

Dave