[dm-devel] [PATCH] block: silently error unsupported empty barriers too
Mikulas Patocka
mpatocka at redhat.com
Thu Aug 6 18:50:49 PDT 2009
On Thu, 6 Aug 2009, Alasdair G Kergon wrote:
> On Thu, Aug 06, 2009 at 12:14:17PM +0100, Mark McLoughlin wrote:
> > We should error all barriers, even empty barriers, on devices like
> > virtio_blk which don't support them.
>
> Have you considered whether or not virtio_blk actually needs to
> support empty barriers?
>
> Alasdair
This is only for request-based drivers, where it is the responsibility of
blk-core to translate barriers. I think the empty barrier request anyway
in blk_do_ordered, but with an error message. So the patch changes it to
discard it early and queitly. It seems ok.
Mikulas
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