From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:34767) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UWOUb-0005ci-3u for qemu-devel@nongnu.org; Sun, 28 Apr 2013 06:06:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UWOUW-0000Tb-DA for qemu-devel@nongnu.org; Sun, 28 Apr 2013 06:06:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22183) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UWOUW-0000TV-4s for qemu-devel@nongnu.org; Sun, 28 Apr 2013 06:05:56 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r3SA5t2n030431 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Sun, 28 Apr 2013 06:05:55 -0400 Date: Sun, 28 Apr 2013 18:05:53 +0800 From: Fam Zheng Message-ID: <20130428100553.GB28366@localhost.localdomain> References: <4fe304399e0d00138fefcfffaae97ae5a16de552.1366726446.git.jcody@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4fe304399e0d00138fefcfffaae97ae5a16de552.1366726446.git.jcody@redhat.com> Subject: Re: [Qemu-devel] [PATCH v2 5/5] block: add header update capability for VHDX images. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jeff Cody Cc: kwolf@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com On Tue, 04/23 10:24, Jeff Cody wrote: > if (flags & BDRV_O_RDWR) { > - ret = -ENOTSUP; > - goto fail; > + vhdx_update_headers(bs, s, false); Do we really have to update the header immediately on RW open? I assume when implementing vhdx_co_writev, this is guaranteed to get called before other write. In that case we don't need it here, which means we don't change anything if no user write, even for RW opened file. -- Fam