Commit a0cf7ea9 authored Jun 22, 2009 by Hannes Reinecke Committed by Alasdair G Kergon Jun 22, 2009

dm mpath: change attached scsi_dh



When specifying a different hardware handler via multipath
features we should be able to override the built-in defaults.

The problem here is the hardware table from scsi_dh is compiled
in and cannot be changed from userland. The multipath.conf OTOH
is purely user-defined and, what's more, the user might have a valid
reason for modifying it.
(EG EMC Clariion can well be run in PNR mode even though ALUA is
active, or the user might want to try ALUA on any as-of-yet unknown
devices)

So _not_ allowing multipath to override the device handler setting
will just add to the confusion and makes error tracking even more
difficult.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

parent 4d89b7b4

drivers/md/dm-mpath.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -597,9 +597,20 @@ static struct pgpath parse_path(struct arg_set as, struct path_selector *ps,
		}

		if (m->hw_handler_name) {
		r = scsi_dh_attach(bdev_get_queue(p->path.dev->bdev),
		m->hw_handler_name);
		struct request_queue *q = bdev_get_queue(p->path.dev->bdev);

		r = scsi_dh_attach(q, m->hw_handler_name);
		if (r == -EBUSY) {
		/*
		* Already attached to different hw_handler,
		* try to reattach with correct one.
		*/
		scsi_dh_detach(q);
		r = scsi_dh_attach(q, m->hw_handler_name);
		}

		if (r < 0) {
		ti->error = "error attaching hardware handler";
		dm_put_device(ti, p->path.dev);
		goto bad;
		}

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