From nobody Thu Nov 13 19:24:56 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1582030162624763.0824063076994; Tue, 18 Feb 2020 04:49:22 -0800 (PST) Received: from localhost ([::1]:33975 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j42JV-0006JD-Fy for importer@patchew.org; Tue, 18 Feb 2020 07:49:21 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:39015) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j42Dl-0004dZ-7n for qemu-devel@nongnu.org; Tue, 18 Feb 2020 07:43:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j42Dk-0001Dk-26 for qemu-devel@nongnu.org; Tue, 18 Feb 2020 07:43:25 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:44792 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j42Dj-0001DZ-VF for qemu-devel@nongnu.org; Tue, 18 Feb 2020 07:43:24 -0500 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-139-0-0zy09YPo6dhaD3xZjfjw-1; Tue, 18 Feb 2020 07:43:16 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C062E13EA; Tue, 18 Feb 2020 12:43:15 +0000 (UTC) Received: from localhost (unknown [10.36.118.17]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 330BA100194E; Tue, 18 Feb 2020 12:43:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582029803; 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=CoXOBQPAPA2CnsqwWNkbNSUQjhaIB3ZBKoZqaBZg2Gw=; b=D5lymNz+0VlNLD+p8DahjSoEmLfF+/yOudeDPwbOYQ8ND2tH2qJva1uCWSv6aq3QbXTWVs MIPbr7wDKKT/lEEmDJuoOqLce6QO5QGZ55l3gx+f3ei0WHFe/O1btOMBxLrwZa683s6H3k IwojM1I0xKIFz4uX3QeFE3J8IDDcFWM= From: Max Reitz To: qemu-block@nongnu.org Subject: [PATCH v3 09/33] block: Add generic bdrv_inherited_options() Date: Tue, 18 Feb 2020 13:42:18 +0100 Message-Id: <20200218124242.584644-10-mreitz@redhat.com> In-Reply-To: <20200218124242.584644-1-mreitz@redhat.com> References: <20200218124242.584644-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-MC-Unique: 0-0zy09YPo6dhaD3xZjfjw-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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 , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" 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 Reviewed-by: Eric Blake --- block.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) diff --git a/block.c b/block.c index c33f0e9b42..9179b9b604 100644 --- a/block.c +++ b/block.c @@ -998,6 +998,90 @@ 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