From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:52908) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SfAsN-0007Ct-Pb for qemu-devel@nongnu.org; Thu, 14 Jun 2012 10:18:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SfAsL-0008MY-W1 for qemu-devel@nongnu.org; Thu, 14 Jun 2012 10:18:19 -0400 Received: from mail-wg0-f53.google.com ([74.125.82.53]:36980) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SfAsL-0008MP-My for qemu-devel@nongnu.org; Thu, 14 Jun 2012 10:18:17 -0400 Received: by wgbfm10 with SMTP id fm10so1630855wgb.10 for ; Thu, 14 Jun 2012 07:18:15 -0700 (PDT) MIME-Version: 1.0 Sender: donald.open@gmail.com In-Reply-To: <4FD9F104.1010209@redhat.com> References: <1339598189-17933-1-git-send-email-wdongxu@linux.vnet.ibm.com> <1339598189-17933-4-git-send-email-wdongxu@linux.vnet.ibm.com> <4FD9C24A.70906@redhat.com> <4FD9F104.1010209@redhat.com> From: Dong Xu Wang Date: Thu, 14 Jun 2012 22:17:35 +0800 Message-ID: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH 4/6] qemu-img: add-cow will not support convert List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Stefan Hajnoczi , qemu-devel@nongnu.org On Thu, Jun 14, 2012 at 10:11 PM, Kevin Wolf wrote: > Am 14.06.2012 16:06, schrieb Dong Xu Wang: >> On Thu, Jun 14, 2012 at 6:51 PM, Kevin Wolf wrote: >>> Am 13.06.2012 16:36, schrieb Dong Xu Wang: >>>> add-cow file can't live alone, must together will image_file and backi= ng_file. >>>> If we implement qemu-img convert operation for add-cow file format, we= must >>>> create image_file and backing_file manually, that will be confused for= users, >>>> so we just ignore add-cow format while doing converting. >>>> >>>> Signed-off-by: Dong Xu Wang >>> >>> NACK. >>> >>> This stupid "let's drop the feature, it might confuse users" attitude i= s >>> known from Gnome, but not from qemu. >>> >>> There's no technical reason to forbid it and anyone who manages to >>> create a valid add-cow image will also be able to specify the very same >>> options to a convert command. Also, having image format specific code i= n >>> qemu-img is evil. >>> >> >> If I implement add-cow convert command, I am wondering which method shou= ld >> I use: >> 1) create add-cow, and its backing_file, and its image_file, =A0then we >> need 3 files. >> 2) create add-cow(with all bitmap marked to allocated), and its >> image_file, then we >> =A0 =A0 need 2 files. >> >> 2) will be easier, I should let .add-cow file can live only with >> image_file, without backing_file. >> >> I think both 1) and 2) need add code to qemu-img.c. Or I will have to cr= eate >> image_file automaticly in add_cow_create function. >> >> Can you give some comments on how to implement convert? Thanks. > > Just leave it alone and it will work. > > qemu-img convert takes the same options as qemu-img create. So like for > any other image you specify the backing file with -b or -o backing_file, > and for add-cow images to be successfully created you also need to > specify -o image_file. > "-o image_file", the image_file should be precreated? Or I should created i= t manually? > Kevin >