[dm-devel] Re: Write barriers on MD RAID1

[NeilBrown]

On Wed, June 24, 2009 5:09 pm, Alasdair G Kergon wrote:
> On Wed, Jun 24, 2009 at 01:43:35PM +1000, Neil Brown wrote:
>> Since this test was added, barriers have not worked on md, and (I
>> think) dm and similar devices that don't use __make_request and so
>> don't bother to set next_ordered.
>
> In dm, we added this:
>
> +       blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN, NULL);
>

I obviously didn't grep for the right thing.

This will obviously work, but I can't help thinking it is in the wrong
place.  I don't even have a queue in md/raid1, so making a statement
about how it is ordered just doesn't make sense.

Jens?

NeilBrown