On Wed, May 09 2012 at 2:10pm -0400, Moger, Babu <Babu.Moger@xxxxxxxxxx> wrote: > Mike, > > > -----Original Message----- > > From: Mike Snitzer [mailto:snitzer@xxxxxxxxxx] > > Sent: Tuesday, May 08, 2012 4:56 PM > > To: dm-devel@xxxxxxxxxx > > Cc: agk@xxxxxxxxxx; hare@xxxxxxx; Moger, Babu; sekharan@xxxxxxxxxx; > > Mike Snitzer > > Subject: [PATCH v2 4/5] dm mpath: add 'default_hw_handler' feature > > > > From: Hannes Reinecke <hare@xxxxxxx> > > > > When specifying the feature 'default_hw_handler' multipath will be use > > the currently attached hardware handler instead of trying to attach the > > one specified during table load. If no hardware handler is attached the > > specified hardware handler will be used. > > I am trying to test these patches right now. What is the expectation from > Multipath tools for this to work correctly. Do I have to pass following > Parameters? > > hardware_handler "1 alua" > features "1 default_hw_handler" Yes. > It appears to me that the first line will forcibly load the alua handler even if > the default handler is different. Are you saying that based on testing or based on code review? > > diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c > > index c351607..0fc6849 100644 > > --- a/drivers/md/dm-mpath.c > > +++ b/drivers/md/dm-mpath.c > > @@ -585,9 +587,18 @@ static struct pgpath *parse_path(struct dm_arg_set > > *as, struct path_selector *ps > > goto bad; > > } > > > > - if (m->hw_handler_name) { > > - struct request_queue *q = bdev_get_queue(p->path.dev- > > >bdev); > > + if (m->use_default_hw_handler || m->hw_handler_name) > > + q = bdev_get_queue(p->path.dev->bdev); > > + > > + if (m->use_default_hw_handler) { > > + const char *attached_handler_name = scsi_dh_attached_handler_name(q); > > + if (attached_handler_name) { > > + kfree(m->hw_handler_name); > > + m->hw_handler_name = kstrdup(attached_handler_name, GFP_KERNEL); > > + } > > + } > > > > + if (m->hw_handler_name) { > > r = scsi_dh_attach(q, m->hw_handler_name); > > if (r == -EBUSY) { > > /* The above hunk is what will cause the currently attached device handler to be used. But if a device handler is _not_ attached then we fallback to using the provided 'hardware_handler'. So are you testing this patch with a device handler having already been attached? Mike -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
