From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: qdisk vs. file as vbd type
Date: Fri, 10 Jan 2014 10:29:48 -0500
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To: Olaf Hering <olaf@aepfle.de>
Cc: Ian Campbell <Ian.Campbell@citrix.com>, xen-devel@lists.xen.org
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On Fri, Jan 10, 2014 at 04:19:56PM +0100, Olaf Hering wrote:
> [ removing Li who is no longer with Novell ]
> 
> On Fri, Jan 10, Konrad Rzeszutek Wilk wrote:
> 
> > You are looking at:
> > ed30bf317       (Li Dongyang    2011-09-01 18:39:09 +0800       1664)   } else if (strncmp(type, "file", 4) == 0)
> > ed30bf317       (Li Dongyang    2011-09-01 18:39:09 +0800       1665)           info->feature_discard = 1;
> > ed30bf317       (Li Dongyang    2011-09-01 18:39:09 +0800       1666)
> > ed30bf317       (Li Dongyang    2011-09-01 18:39:09 +0800       1667)   kfree(type);
> > ed30bf317       (Li Dongyang    2011-09-01 18:39:09 +0800       1668)}
> > ed30bf317       (Li Dongyang    2011-09-01 18:39:09 +0800       1669)
> > 
> > My recollection is that at the time the patches were developed, loop
> > was not able to do discard operations. That has since changed and
> > loop can do it. Hence the force of =1 was added in.
> 
> If the backend cant do discard then it should not advertise the feature.

<nods>
> 
> Are you ok with me sending a patch which simplifies this function?

Yes of course!
> 
> Olaf