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=-8.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 B755EC2D0A3 for ; Mon, 9 Nov 2020 13:46:22 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3222C2068D for ; Mon, 9 Nov 2020 13:46:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="h7rqZ839" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3222C2068D 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 ([::1]:40092 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kc7Uz-0002lI-2X for qemu-devel@archiver.kernel.org; Mon, 09 Nov 2020 08:46:21 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59368) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kc7Pn-0006kZ-Od for qemu-devel@nongnu.org; Mon, 09 Nov 2020 08:41:01 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:48464) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kc7Pl-0001Jp-Qw for qemu-devel@nongnu.org; Mon, 09 Nov 2020 08:40:59 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604929256; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TYmBXwN6RuPXc6s/3jx/jr6UDT8z+j2zKrqPmFDeEUA=; b=h7rqZ839V/2eFVqSwEtPE+EvmpauPe6hMFkQfhnu9YR9rh69aIsgry/Msf2Hc/PGR/O8ZK KZgtqNGwKJAuRiYcL2nFfBUsPZDBoKB8zwCyVewL5bsMAdRQnJE7DXTpH7qtkwiNDSDLHb evgFVS9sXfTpuSbMwDRbv01T83oGXRY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-350-K2SZ4BAyOAW6hOgPPZG1aA-1; Mon, 09 Nov 2020 08:40:54 -0500 X-MC-Unique: K2SZ4BAyOAW6hOgPPZG1aA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 742BF801FDE; Mon, 9 Nov 2020 13:40:53 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-113-179.ams2.redhat.com [10.36.113.179]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2485760C56; Mon, 9 Nov 2020 13:40:50 +0000 (UTC) Subject: Re: [PATCH v2 7/7] block: drop tighten_restrictions To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20201106124241.16950-1-vsementsov@virtuozzo.com> <20201106124241.16950-8-vsementsov@virtuozzo.com> From: Max Reitz Message-ID: Date: Mon, 9 Nov 2020 14:40:49 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20201106124241.16950-8-vsementsov@virtuozzo.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/09 01:25:23 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, den@openvz.org, berto@igalia.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 06.11.20 13:42, Vladimir Sementsov-Ogievskiy wrote: > The only users of this thing are: > 1. bdrv_child_try_set_perm, to ignore failures on loosen restrictions > 2. assertion in bdrv_replace_child > 3. assertion in bdrv_inactivate_recurse > > Assertions are not enough reason for overcomplication the permission > update system. So, look at bdrv_child_try_set_perm. > > We are interested in tighten_restrictions only on failure. But on > failure this field is not reliable: we may fail in the middle of > permission update, some nodes are not touched and we don't know should > their permissions be tighten or not. So, we rely on the fact that if we > loose restrictions on some node (or BdrvChild), we'll not tighten > restriction in the whole subtree as part of this update (assertions 2 > and 3 rely on this fact as well). And, if we rely on this fact anyway, > we can just check it on top, and don't pass additional pointer through > the whole recursive infrastructure. > > Note also, that further patches will fix real bugs in permission update > system, so now is good time to simplify it, as a help for further > refactorings. > > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > block.c | 88 +++++++++++---------------------------------------------- > 1 file changed, 17 insertions(+), 71 deletions(-) Reviewed-by: Max Reitz