Re: dm-multipath test scripts

[Mike Snitzer <snitzer@redhat.com>]

On Fri, Feb 19 2016 at  2:42pm -0500,
Mike Snitzer <snitzer@redhat.com> wrote:

> On Fri, Feb 19 2016 at  3:37am -0500,
> Junichi Nomura <j-nomura@ce.jp.nec.com> wrote:
> 
> > On 02/19/16 09:33, Nomura Junichi wrote:
> > > On 02/19/16 02:17, Mike Snitzer wrote:
> > >> What is the last kernel version that your scripts have worked on?
> > > 
> > > v4.4 worked fine. I'll check with v4.5-rc4 when I get a machine.
> > 
> > v4.5-rc4 works fine, too.
> 
> Have you been running with blk-mq?
> Either by setting CONFIG_DM_MQ_DEFAULT or:
> echo Y > /sys/module/dm_mod/parameters/use_blk_mq
> 
> I'm seeing test_02_sdev_delete fail with blk-mq enabled.

I only see failure if I stack dm-mq ontop of old non-mq scsi devices with:

echo N > /sys/module/scsi_mod/parameters/use_blk_mq
echo Y > /sys/module/dm_mod/parameters/use_blk_mq

If I use scsi-mq for the underlying devices all works fine (been testing
the latest dm-4.6 branch though, I'll go back and try stock 4.5-rc4 just
to double check).

But this makes me think the novelty of having dm-mq support stacking on
non-blk-mq devices was misplaced.  It is a senseless config.  I'll
probably remove support for such stacking soon (next week).