Re: [dm-devel] dm-thinp bug

[Joe Thornber <thornber redhat com>]

On Wed, 2011-04-27 at 04:39 -0400, Christoph Hellwig wrote:
> On Wed, Apr 27, 2011 at 09:27:37AM +0100, Joe Thornber wrote:
> > On Tue, 2011-04-26 at 14:47 -0400, Christoph Hellwig wrote:
> > > I can reproduce a bug in virtio triggered by running under dm-thinp by
> > > just copying lots of files from my home directory into a freshly created
> > > filesystem on dm-thinp.
> > 
> > Finally someone has tried using it!  I'll look into this today.
> 
> I actually used the earlier version you posted and didn't reproduce it
> there.  I have a gut feeling it's related to barriers, as I probably
> just did a basic ext3 test back then.

I hope this isn't the case.

> 
> One thing that springs to mind is that both the thinp and multisnap
> targets don't appear to support empty barriers (that is REQ_FLUSH
> without a payload), because they don't set ti->num_flush_requests, but
> I'm not sure that's related.

Fixed in thinp and multisnap public repos.

- Joe