From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH V4 3/3] xen-blkback: discard requests handling in blkback driver Date: Thu, 1 Sep 2011 11:28:26 -0400 Message-ID: <20110901152826.GB6965@dumpdata.com> References: <7f85bb71f76deed2537438928fa8b6dafb6a51f8.1314872306.git.lidongyang@novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <7f85bb71f76deed2537438928fa8b6dafb6a51f8.1314872306.git.lidongyang@novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Li Dongyang Cc: xen-devel@lists.xensource.com, owen.smith@citrix.com, JBeulich@novell.com List-Id: xen-devel@lists.xenproject.org On Thu, Sep 01, 2011 at 06:39:10PM +0800, Li Dongyang wrote: > Now blkback driver can handle the discard request from guest, we will > forward the request to phy device if it really has discard support, or we'll > punch a hole on the image file. The description should read: xen-blkback: Implement discard requests handling If the backend device (or loopback file) supports discard requests then advertise it to the frontend via 'feature-discard'. Implementation wise - if the backend is 'phy' - use blkdev_issue_discard, while if it is 'file', then punch a hole in the image file. Signed-off-by: Li Dongyang .. snip.. > + if (err == -EOPNOTSUPP) { > + pr_debug(DRV_PFX "blkback: discard op failed, " ^^^^^^^ - get rid of that. The DRV_PFX already provides the 'xen-blkback' string.