From nobody Tue Feb 10 13:34:27 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; 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=pass(p=none dis=none) header.from=yandex-team.ru ARC-Seal: i=1; a=rsa-sha256; t=1658868668; cv=none; d=zohomail.com; s=zohoarc; b=NUaA0To/2bcAruoGAVAgZoPgMZD7v+II2KF6U7iLzVTTIaMKaw0nbVuLhWyowUOMlQT8ztMkqV+SEEKdcuIs424rVUgTZhCokUxaXIOrWp2zyrukhwolCAfmAzLhTPrNDMcA9goWdGnrsMIhETR0ySDMS/OPy8Se8e1zInsOCjA= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1658868668; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=fdnzy21DcNkb5I8H6BYC0uuZF3cLw3rYot4unxKH7aQ=; b=eZdjGSt7skI8Ww2gPEdMbUaG2YSM9sONB4ozORlPVJFF2ri0yxumt0HNDldwhf8EBbzEWedAuUVGWHvKM6gHlzzh4ofSlsYqUE9L1cBG/LrhZkHRhfiVtiTmis9494dCk7CXzp3an/MX4kZnkSEgOr18KtV3QFwt87tRXjDS5cE= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; 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=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1658868668097929.6254045422212; Tue, 26 Jul 2022 13:51:08 -0700 (PDT) Received: from localhost ([::1]:56014 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oGRWD-0006Ma-Tl for importer@patchew.org; Tue, 26 Jul 2022 16:51:05 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58460) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oGQue-0001CZ-HB; Tue, 26 Jul 2022 16:12:16 -0400 Received: from forwardcorp1o.mail.yandex.net ([2a02:6b8:0:1a2d::193]:47324) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oGQua-0001F7-Gn; Tue, 26 Jul 2022 16:12:15 -0400 Received: from sas1-7470331623bb.qloud-c.yandex.net (sas1-7470331623bb.qloud-c.yandex.net [IPv6:2a02:6b8:c08:bd1e:0:640:7470:3316]) by forwardcorp1o.mail.yandex.net (Yandex) with ESMTP id C366F2E0DC9; Tue, 26 Jul 2022 23:12:03 +0300 (MSK) Received: from localhost.localdomain (172.31.44.48-vpn.dhcp.yndx.net [172.31.44.48]) by sas1-7470331623bb.qloud-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id ZssKVYgWJm-C2O0Ts3Z; Tue, 26 Jul 2022 23:12:03 +0300 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (Client certificate not present) X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1658866323; bh=fdnzy21DcNkb5I8H6BYC0uuZF3cLw3rYot4unxKH7aQ=; h=Message-Id:Date:In-Reply-To:Cc:Subject:References:To:From; b=vLWsB87lXiQSsZr2inLKq63b5n9te+xmKuaPPmaF7V0EQETarZY43zCAaSljpa/Fk QcqUmTtFrR62t+i6a3JgE7PcXff8PmmdK290CxAFXB5eAP9zdjK0x5OLGYRFkfZFnh m2yY7jvy8Ev4iNVe3EZhm7zkrLuu36LSIcyRYibg= Authentication-Results: sas1-7470331623bb.qloud-c.yandex.net; dkim=pass header.i=@yandex-team.ru From: Vladimir Sementsov-Ogievskiy To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, kwolf@redhat.com, hreitz@redhat.com, vsementsov@yandex-team.ru Subject: [PATCH v7 08/15] block/snapshot: stress that we fallback to primary child Date: Tue, 26 Jul 2022 23:11:27 +0300 Message-Id: <20220726201134.924743-9-vsementsov@yandex-team.ru> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220726201134.924743-1-vsementsov@yandex-team.ru> References: <20220726201134.924743-1-vsementsov@yandex-team.ru> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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; Received-SPF: pass client-ip=2a02:6b8:0:1a2d::193; envelope-from=vsementsov@yandex-team.ru; helo=forwardcorp1o.mail.yandex.net 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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @yandex-team.ru) X-ZM-MESSAGEID: 1658868669088100001 Content-Type: text/plain; charset="utf-8" Actually what we chose is a primary child. Let's stress it in the code. We are going to drop indirect pointer logic here in future. Actually this commit simplifies the future work: we drop use of indirection in the assertion now. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Hanna Reitz --- block/snapshot.c | 30 ++++++++++-------------------- 1 file changed, 10 insertions(+), 20 deletions(-) diff --git a/block/snapshot.c b/block/snapshot.c index d6f53c3065..75e8d3a937 100644 --- a/block/snapshot.c +++ b/block/snapshot.c @@ -161,21 +161,14 @@ bool bdrv_snapshot_find_by_id_and_name(BlockDriverSta= te *bs, static BdrvChild **bdrv_snapshot_fallback_ptr(BlockDriverState *bs) { BdrvChild **fallback; - BdrvChild *child; + BdrvChild *child =3D bdrv_primary_child(bs); =20 - /* - * The only BdrvChild pointers that are safe to modify (and which - * we can thus return a reference to) are bs->file and - * bs->backing. - */ - fallback =3D &bs->file; - if (!*fallback && bs->drv && bs->drv->is_filter) { - fallback =3D &bs->backing; - } - - if (!*fallback) { + /* We allow fallback only to primary child */ + if (!child) { return NULL; } + fallback =3D (child =3D=3D bs->file ? &bs->file : &bs->backing); + assert(*fallback =3D=3D child); =20 /* * Check that there are no other children that would need to be @@ -309,15 +302,12 @@ int bdrv_snapshot_goto(BlockDriverState *bs, } =20 /* - * fallback_ptr is &bs->file or &bs->backing. *fallback_ptr - * was closed above and set to NULL, but the .bdrv_open() call - * has opened it again, because we set the respective option - * (with the qdict_put_str() call above). - * Assert that .bdrv_open() has attached some child on - * *fallback_ptr, and that it has attached the one we wanted - * it to (i.e., fallback_bs). + * fallback was a primary child. It was closed above and set to NU= LL, + * but the .bdrv_open() call has opened it again, because we set t= he + * respective option (with the qdict_put_str() call above). + * Assert that .bdrv_open() has attached the right BDS as primary = child. */ - assert(*fallback_ptr && fallback_bs =3D=3D (*fallback_ptr)->bs); + assert(bdrv_primary_bs(bs) =3D=3D fallback_bs); bdrv_unref(fallback_bs); return ret; } --=20 2.25.1