From patchwork Tue Aug 14 07:25:51 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Fam Zheng X-Patchwork-Id: 957373 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 41qPKh43Fnz9s9F for ; Tue, 14 Aug 2018 17:26:32 +1000 (AEST) Received: from localhost ([::1]:42791 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fpTio-0001uo-4H for incoming@patchwork.ozlabs.org; Tue, 14 Aug 2018 03:26:30 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51109) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fpTiU-0001tN-Cv for qemu-devel@nongnu.org; Tue, 14 Aug 2018 03:26:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fpTiT-0006RQ-HU for qemu-devel@nongnu.org; Tue, 14 Aug 2018 03:26:10 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:55414 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 1fpTiO-0006Nb-9i; Tue, 14 Aug 2018 03:26:04 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D75F48197039; Tue, 14 Aug 2018 07:26:03 +0000 (UTC) Received: from lemon.usersys.redhat.com (ovpn-12-86.pek2.redhat.com [10.72.12.86]) by smtp.corp.redhat.com (Postfix) with ESMTP id D64057C26; Tue, 14 Aug 2018 07:25:59 +0000 (UTC) From: Fam Zheng To: qemu-devel@nongnu.org Date: Tue, 14 Aug 2018 15:25:51 +0800 Message-Id: <20180814072551.15465-1-famz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 14 Aug 2018 07:26:03 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 14 Aug 2018 07:26:03 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.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] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH] luks: Allow share-rw=on 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+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Format drivers such as qcow2 don't allow sharing the same image between two QEMU instances in order to prevent image corruptions, because of metadata cache. LUKS driver don't modify metadata except for when creating image, so it is safe to relax the permission. This makes share-rw=on property work on virtual devices. Suggested-by: Daniel P. Berrangé Signed-off-by: Fam Zheng Reviewed-by: Daniel P. Berrangé --- block/crypto.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/crypto.c b/block/crypto.c index 146d81c90a..33ee01bebd 100644 --- a/block/crypto.c +++ b/block/crypto.c @@ -627,7 +627,9 @@ BlockDriver bdrv_crypto_luks = { .bdrv_probe = block_crypto_probe_luks, .bdrv_open = block_crypto_open_luks, .bdrv_close = block_crypto_close, - .bdrv_child_perm = bdrv_format_default_perms, + /* This driver doesn't modify LUKS metadata except when creating image. + * Allow share-rw=on as a special case. */ + .bdrv_child_perm = bdrv_filter_default_perms, .bdrv_co_create = block_crypto_co_create_luks, .bdrv_co_create_opts = block_crypto_co_create_opts_luks, .bdrv_co_truncate = block_crypto_co_truncate,