[dm-devel] data corruption with 'splt' workload to XFS on DM cache with its 3 underlying devices being on same NVMe device

[Mike Snitzer]

On Tue, Jul 24 2018 at 10:25am -0400,
Bart Van Assche <Bart.VanAssche at wdc.com> wrote:

> On Tue, 2018-07-24 at 08:00 +0200, Hannes Reinecke wrote:
> > So, have you tested that request-based multipathing works on a partition 
> > _at all_? I'm not sure if partition mapping is done correctly here; we 
> > never remap the start of the request (nor bio, come to speak of it), so 
> > it looks as if we would be doing the wrong things here.
> > 
> > Have you checked that partition remapping is done correctly?
> 
> I think generic_make_request() takes care of partition remapping by calling
> blk_partition_remap(). generic_make_request() is called by submit_bio(). Is
> that sufficient to cover all dm drivers?

Seems not for request-based DM (see my previous reply in this thread).

But bio-based DM-multipath seems to work just fine.