From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61E23C282CE for ; Wed, 22 May 2019 17:12:02 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3C1242081C for ; Wed, 22 May 2019 17:12:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C1242081C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:48048 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hTUmX-0000Tx-Ei for qemu-devel@archiver.kernel.org; Wed, 22 May 2019 13:12:01 -0400 Received: from eggs.gnu.org ([209.51.188.92]:40815) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hTUfI-0003ey-Sb for qemu-devel@nongnu.org; Wed, 22 May 2019 13:04:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hTUfH-0007vK-Og for qemu-devel@nongnu.org; Wed, 22 May 2019 13:04:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33164) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hTUfC-0007mQ-MN; Wed, 22 May 2019 13:04:28 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id ECD7A8667A; Wed, 22 May 2019 17:04:14 +0000 (UTC) Received: from localhost (ovpn-204-123.brq.redhat.com [10.40.204.123]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 83E84600C0; Wed, 22 May 2019 17:04:14 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 22 May 2019 19:03:49 +0200 Message-Id: <20190522170352.12020-6-mreitz@redhat.com> In-Reply-To: <20190522170352.12020-1-mreitz@redhat.com> References: <20190522170352.12020-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Wed, 22 May 2019 17:04:20 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3 5/8] block: Fix order in bdrv_replace_child() 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-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" We have to start by applying the permission restrictions to new_bs before we can loosen them on old_bs. See the comment for the explanation. Signed-off-by: Max Reitz Reviewed-by: Kevin Wolf --- block.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/block.c b/block.c index 02157e0652..3029f5c302 100644 --- a/block.c +++ b/block.c @@ -2240,6 +2240,19 @@ static void bdrv_replace_child(BdrvChild *child, B= lockDriverState *new_bs) =20 bdrv_replace_child_noperm(child, new_bs); =20 + /* + * Start with the new node's permissions. If @new_bs is a (direct + * or indirect) child of @old_bs, we must complete the permission + * update on @new_bs before we loosen the restrictions on @old_bs. + * Otherwise, bdrv_check_perm() on @old_bs would re-initiate + * updating the permissions of @new_bs, and thus not purely loosen + * restrictions. + */ + if (new_bs) { + bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm); + bdrv_set_perm(new_bs, perm, shared_perm); + } + if (old_bs) { /* Update permissions for old node. This is guaranteed to succee= d * because we're just taking a parent away, so we're loosening @@ -2248,11 +2261,6 @@ static void bdrv_replace_child(BdrvChild *child, B= lockDriverState *new_bs) bdrv_check_perm(old_bs, NULL, perm, shared_perm, NULL, &error_ab= ort); bdrv_set_perm(old_bs, perm, shared_perm); } - - if (new_bs) { - bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm); - bdrv_set_perm(new_bs, perm, shared_perm); - } } =20 /* --=20 2.21.0