Re: [PATCH 09/14] xfs: introduce new locks for the log grant ticket wait queues

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Thu, Dec 02, 2010 at 01:10:31PM +1100, Dave Chinner wrote:
> On Wed, Dec 01, 2010 at 08:12:08AM -0500, Christoph Hellwig wrote:
> > > +         /* co-ordinate with xfs_log_force_shutdown */
> > > +         if (XLOG_FORCED_SHUTDOWN(log)) {
> > > +                 spin_unlock(&log->l_grant_reserve_lock);
> > > +                 goto error_return;
> > > +         }
> > 
> > Where is this coming from?  Otherwise the patch looks good to me.
> 
> To handles the race condition between xfs_log_force_shutdown() clearing
> all the tickets off the queue and a racing log reserve that had
> already checked the shutdown flag and was spinning waiting for the
> reserve lock to add the ticket to the queue. The race condition is
> documented in xfs_log_force_shutdown()...

Ok.  Please add something like that to the patch description.