From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51195) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VrJRW-0003zU-J1 for qemu-devel@nongnu.org; Thu, 12 Dec 2013 22:29:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VrJRP-0004zP-9C for qemu-devel@nongnu.org; Thu, 12 Dec 2013 22:29:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56194) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VrJRP-0004zF-1k for qemu-devel@nongnu.org; Thu, 12 Dec 2013 22:29:27 -0500 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 rBD3TQPA009330 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 12 Dec 2013 22:29:26 -0500 Message-ID: <52AA7F08.2050203@redhat.com> Date: Fri, 13 Dec 2013 11:29:12 +0800 From: Fam Zheng MIME-Version: 1.0 References: <1386836626-6436-1-git-send-email-famz@redhat.com> <1386836626-6436-9-git-send-email-famz@redhat.com> <87fvpy6umj.fsf@blackfin.pond.sub.org> In-Reply-To: <87fvpy6umj.fsf@blackfin.pond.sub.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v7 08/10] block: Add checks of blocker in block operations List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: kwolf@redhat.com, qemu-devel@nongnu.org, rjones@redhat.com, imain@redhat.com, stefanha@redhat.com, pbonzini@redhat.com On 2013=E5=B9=B412=E6=9C=8812=E6=97=A5 21:56, Markus Armbruster wrote: > Fam Zheng writes: > >> Before operate on a BlockDriverState, respective types are checked >> against bs->op_blockers and it will error out if there's a blocker. >> >> Signed-off-by: Fam Zheng > > So this patch adds protection against "two of the same kind > simultaneously". How could we check it's complete? > > Have we pondered the more general problem of which "operations" > (whatever that is) exclude each other? > Good point. For what we want now, I think these extra checks are not=20 required. I think these could be added in a separate series if any.=20 Planning to drop it for next revision but the discussion is still open. Thanks, Fam