From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=38834 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PlKE9-00034Q-Me for qemu-devel@nongnu.org; Fri, 04 Feb 2011 06:53:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PlKE8-0000pF-K7 for qemu-devel@nongnu.org; Fri, 04 Feb 2011 06:53:25 -0500 Received: from mail-ww0-f53.google.com ([74.125.82.53]:45306) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PlKE8-0000p2-Fl for qemu-devel@nongnu.org; Fri, 04 Feb 2011 06:53:24 -0500 Received: by wwi18 with SMTP id 18so2136025wwi.10 for ; Fri, 04 Feb 2011 03:53:23 -0800 (PST) Date: Fri, 4 Feb 2011 10:59:59 +0000 From: Stefan Hajnoczi Subject: Re: [Qemu-devel] [PATCH] qcow2: Add full image preallocation option Message-ID: <20110204105959.GA24818@stefanha-thinkpad.localdomain> References: <1296143534-13495-1-git-send-email-kwolf@redhat.com> <4D41AF53.8070701@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D41AF53.8070701@codemonkey.ws> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Kevin Wolf , qemu-devel@nongnu.org On Thu, Jan 27, 2011 at 11:45:55AM -0600, Anthony Liguori wrote: > On 01/27/2011 09:52 AM, Kevin Wolf wrote: > >This adds a preallocation=full mode to qcow2 image creation, which does not > >only allocate metadata for the whole image, but also writes zeros to it, > >creating a non-sparse image file. > > The writing zeros bit is in order to support physical devices? > Would it be better to have a flag in BlockDriverState that indicated > whether uninitialized sectors could be assumed to be zero filled and > key off of that? There is already: int bdrv_has_zero_init(BlockDriverState *bs); Stefan