>
> >
> > -----Original Message-----
> > From:
linux-kernel-owner@vger.kernel.org
> > [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of NeilBrown
> > Sent: Sunday, March 02, 2008 5:18 PM
> > To: Andrew Morton
> > Cc: linux-raid@vger.kernel.org; linux-kernel@vger.kernel.org; K.Tanaka
> > Subject: [PATCH 008 of 9] md: Fix possible raid1/raid10 deadlock on read
> > error during resync.
> >
>
> > diff .prev/drivers/md/raid1.c ./drivers/md/raid1.c
> > --- .prev/drivers/md/raid1.c 2008-03-03 11:03:39.000000000 +1100
> > +++ ./drivers/md/raid1.c 2008-03-03 09:56:52.000000000 +1100
> > @@ -704,13 +704,20 @@ static void freeze_array(conf_t *conf)
> > /* stop syncio and normal IO and wait for everything to
> > * go quite.
> > * We increment barrier and nr_waiting, and then
> > - * wait until barrier+nr_pending match nr_queued+2
> > + * wait until nr_pending match nr_queued+1
> > + * This is called in the context of one normal IO request
> > + * that has failed. Thus any sync request that might be pending
> > + * will be blocked by nr_pending, and we need to wait for
> > + * pending IO requests to complete or be queued for re-try.
> > + * Thus the number queued (nr_queued) plus this request (1)
> > + * must match the number of pending IOs (nr_pending) before
> > + * we continue.
> > */
> > spin_lock_irq(&conf->resync_lock);
> > conf->barrier++;
> > conf->nr_waiting++;
> > wait_event_lock_irq(conf->wait_barrier,
> > - conf->barrier+conf->nr_pending ==
> > conf->nr_queued+2,
> > + conf->nr_pending == conf->nr_queued+1,
> > conf->resync_lock,
> > ({ flush_pending_writes(conf);
> > raid1_unplug(conf->mddev->queue); }));
> > --
>
> When we call freeze_array, it is after reschedule_retry, during which conf->nr_queued is already incremented.
> Should we use conf->nr_pending == conf->nr_pending here?
>
