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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 60E07C35247 for ; Tue, 4 Feb 2020 17:12:50 +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 266702084E for ; Tue, 4 Feb 2020 17:12:50 +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="IB4mIe1R" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 266702084E 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]:34726 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iz1kn-00006P-BH for qemu-devel@archiver.kernel.org; Tue, 04 Feb 2020 12:12:49 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:53020) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iz1hS-0002zT-Ld for qemu-devel@nongnu.org; Tue, 04 Feb 2020 12:09:23 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iz1hR-0002VT-Dq for qemu-devel@nongnu.org; Tue, 04 Feb 2020 12:09:22 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:31882 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iz1hR-0002Th-9b for qemu-devel@nongnu.org; Tue, 04 Feb 2020 12:09:21 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580836160; 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=J2l/QtADm9xJSUp/EDvPXwh4NPTqn435JKN5O21Opy8=; b=IB4mIe1Rh9iSSvJQO5cagjHDEMlcURx/Qc+B+NyNfAwxdIqG2Zh8f6K3CAd36ySZs/cNb1 jCpIPNWWCeeX9/uhWIGbAEHW2SLMcSQn3zlacOOFXUU5uBoDaYkKqc7rTdRqUGoQI2HIoS qxt1phTppQU+4hlczxVx3z4GQGudevw= 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-250-bf9Oc6--PvWXDFgGQShS7A-1; Tue, 04 Feb 2020 12:09:19 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E4155133656B; Tue, 4 Feb 2020 17:09:17 +0000 (UTC) Received: from localhost (ovpn-117-98.ams2.redhat.com [10.36.117.98]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5FECE86C4A; Tue, 4 Feb 2020 17:09:17 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PATCH v2 09/33] block: Add generic bdrv_inherited_options() Date: Tue, 4 Feb 2020 18:08:24 +0100 Message-Id: <20200204170848.614480-10-mreitz@redhat.com> In-Reply-To: <20200204170848.614480-1-mreitz@redhat.com> References: <20200204170848.614480-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: bf9Oc6--PvWXDFgGQShS7A-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.120 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: Kevin Wolf , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" After the series this patch belongs to, we want to have a common BdrvChildClass that encompasses all of child_file, child_format, and child_backing. Such a single class needs a single .inherit_options() implementation, and this patch introduces it. The next patch will show how the existing implementations can fall back to it just by passing appropriate BdrvChildRole and parent_is_format values. Signed-off-by: Max Reitz --- block.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) diff --git a/block.c b/block.c index 5b85520515..ab14d52a91 100644 --- a/block.c +++ b/block.c @@ -976,6 +976,90 @@ static void bdrv_temp_snapshot_options(int *child_flag= s, QDict *child_options, *child_flags &=3D ~BDRV_O_NATIVE_AIO; } =20 +/* + * Returns the options and flags that a generic child of a BDS should + * get, based on the given options and flags for the parent BDS. + */ +static void __attribute__((unused)) + bdrv_inherited_options(BdrvChildRole role, bool parent_is_format, + int *child_flags, QDict *child_options, + int parent_flags, QDict *parent_options) +{ + int flags =3D parent_flags; + + /* + * First, decide whether to set, clear, or leave BDRV_O_PROTOCOL. + * Generally, the question to answer is: Should this child be + * format-probed by default? + */ + + /* + * Pure and non-filtered data children of non-format nodes should + * be probed by default (even when the node itself has BDRV_O_PROTOCOL + * set). This only affects a very limited set of drivers (namely + * quorum and blkverify when this comment was written). + * Force-clear BDRV_O_PROTOCOL then. + */ + if (!parent_is_format && + (role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA | + BDRV_CHILD_FILTERED)) =3D=3D + BDRV_CHILD_DATA) + { + flags &=3D ~BDRV_O_PROTOCOL; + } + + /* + * All children of format nodes (except for COW children) and all + * metadata children in general should never be format-probed. + * Force-set BDRV_O_PROTOCOL then. + */ + if ((parent_is_format && !(role & BDRV_CHILD_COW)) || + (role & BDRV_CHILD_METADATA)) + { + flags |=3D BDRV_O_PROTOCOL; + } + + /* + * If the cache mode isn't explicitly set, inherit direct and no-flush= from + * the parent. + */ + qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIREC= T); + qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FL= USH); + qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE= ); + + if (role & BDRV_CHILD_COW) { + /* backing files are always opened read-only */ + qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on"); + qdict_set_default_str(child_options, BDRV_OPT_AUTO_READ_ONLY, "off= "); + } else { + /* Inherit the read-only option from the parent if it's not set */ + qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ON= LY); + qdict_copy_default(child_options, parent_options, + BDRV_OPT_AUTO_READ_ONLY); + } + + if (parent_is_format && !(role & BDRV_CHILD_COW)) { + /* + * Our format drivers take care to send flushes and respect + * unmap policy, so we can default to enable both on lower + * layers regardless of the corresponding parent options. + */ + qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap"); + } + + /* Clear flags that only apply to the top layer */ + flags &=3D ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ= ); + + if (role & BDRV_CHILD_METADATA) { + flags &=3D ~BDRV_O_NO_IO; + } + if (role & BDRV_CHILD_COW) { + flags &=3D ~BDRV_O_TEMPORARY; + } + + *child_flags =3D flags; +} + /* * Returns the options and flags that bs->file should get if a protocol dr= iver * is expected, based on the given options and flags for the parent BDS --=20 2.24.1