From patchwork Fri Mar 9 08:09:08 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fam Zheng X-Patchwork-Id: 10269825 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 9765F603B5 for ; Fri, 9 Mar 2018 08:13:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 84A2F29AAB for ; Fri, 9 Mar 2018 08:13:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7914029D78; Fri, 9 Mar 2018 08:13:37 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 2784029AAB for ; Fri, 9 Mar 2018 08:13:37 +0000 (UTC) Received: from localhost ([::1]:43725 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1euD9k-00049f-DM for patchwork-qemu-devel@patchwork.kernel.org; Fri, 09 Mar 2018 03:13:36 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60312) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1euD5q-0001i6-PR for qemu-devel@nongnu.org; Fri, 09 Mar 2018 03:09:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1euD5p-0008OR-Ls for qemu-devel@nongnu.org; Fri, 09 Mar 2018 03:09:34 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:43330 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1euD5j-0008MU-CY; Fri, 09 Mar 2018 03:09:27 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9916876FBA; Fri, 9 Mar 2018 08:09:25 +0000 (UTC) Received: from lemon.usersys.redhat.com (ovpn-12-195.pek2.redhat.com [10.72.12.195]) by smtp.corp.redhat.com (Postfix) with ESMTP id E144010C6EAB; Fri, 9 Mar 2018 08:09:23 +0000 (UTC) From: Fam Zheng To: qemu-devel@nongnu.org Date: Fri, 9 Mar 2018 16:09:08 +0800 Message-Id: <20180309080910.7274-3-famz@redhat.com> In-Reply-To: <20180309080910.7274-1-famz@redhat.com> References: <20180309080910.7274-1-famz@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Fri, 09 Mar 2018 08:09:25 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Fri, 09 Mar 2018 08:09:25 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'famz@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH 2/4] block: Fix write flags in bdrv_backing_options X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP When the child in question already has write access, we shouldn't change that just because the parent being open/reopen doesn't need it. But if we are inherenting the flags from a writable parent, we shouldn't copy the BDRV_O_RDWR flag, which is consistent with the BDRV_OPT_READ_ONLY option we set. Signed-off-by: Fam Zheng --- block.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/block.c b/block.c index bedbe208e6..937f9fe159 100644 --- a/block.c +++ b/block.c @@ -997,7 +997,10 @@ static void bdrv_backing_options(int *child_flags, QDict *child_options, int parent_flags, QDict *parent_options, int current_flags) { - int flags = parent_flags; + /* write flag should be preserved if the backing file already has it. This + * is important during reopen, to keep "parallel block jobs" work. */ + int write_flag = current_flags & BDRV_O_RDWR; + int flags = parent_flags | write_flag; /* The cache mode is inherited unmodified for backing files; except WCE, * which is only applied on the top level (BlockBackend) */ @@ -1005,9 +1008,13 @@ static void bdrv_backing_options(int *child_flags, QDict *child_options, qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH); qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE); - /* backing files always opened read-only */ - qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on"); - flags &= ~BDRV_O_COPY_ON_READ; + + if (!write_flag) { + flags &= ~BDRV_O_COPY_ON_READ; + /* backing files always opened read-only */ + qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on"); + flags &= ~BDRV_O_RDWR; + } /* snapshot=on is handled on the top layer */ flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);