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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8414AC433EF for ; Tue, 19 Oct 2021 12:26:22 +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 0E15160F93 for ; Tue, 19 Oct 2021 12:26:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 0E15160F93 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:37138 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mcoCD-0001CA-0I for qemu-devel@archiver.kernel.org; Tue, 19 Oct 2021 08:26:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37198) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mco9f-0000Bp-Pm for qemu-devel@nongnu.org; Tue, 19 Oct 2021 08:23:43 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:30046) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mco9a-0002gQ-8v for qemu-devel@nongnu.org; Tue, 19 Oct 2021 08:23:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634646216; 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: in-reply-to:in-reply-to:references:references; bh=dDR8hJWj4p18ll6vpxHJQHo22rZCE1zG/ppJjHd5SKY=; b=WFHeOqvao1RfNqY3DLlFWoNo2qPoRoeNeTM84/L0mWGG7mgMo1hHwfL9sYojS+M2MQ+Gv7 6dV+VR8lVegfy+zxuIV7JBBbwJ8SPNi8UV6lTr8OmY2Ntg3Np249Jv6EGKNw1buuy1AyRa xq6voMSayI7eAhv+Uk7YHSX82JciSrI= 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-522-xtDXIlsvOBeLrZ8LZfmxjg-1; Tue, 19 Oct 2021 08:23:35 -0400 X-MC-Unique: xtDXIlsvOBeLrZ8LZfmxjg-1 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 6753A10A8E00; Tue, 19 Oct 2021 12:23:34 +0000 (UTC) Received: from redhat.com (unknown [10.39.194.68]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2AE4560936; Tue, 19 Oct 2021 12:23:33 +0000 (UTC) Date: Tue, 19 Oct 2021 14:23:31 +0200 From: Kevin Wolf To: Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH] block: Fail gracefully when blockdev-snapshot creates loops Message-ID: References: <20211018134714.48438-1-kwolf@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, T_SPF_TEMPERROR=0.01 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: hreitz@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 18.10.2021 um 16:22 hat Vladimir Sementsov-Ogievskiy geschrieben: > 18.10.2021 16:47, Kevin Wolf wrote: > > Using blockdev-snapshot to append a node as an overlay to itself, or to > > any of its parents, causes crashes. Catch the condition and return an > > error for these cases instead. > > > > Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1824363 > > Signed-off-by: Kevin Wolf > > --- > > block.c | 10 ++++++++++ > > tests/qemu-iotests/085 | 31 ++++++++++++++++++++++++++++++- > > tests/qemu-iotests/085.out | 33 ++++++++++++++++++++++++++++++--- > > 3 files changed, 70 insertions(+), 4 deletions(-) > > > > diff --git a/block.c b/block.c > > index 45f653a88b..231dddf655 100644 > > --- a/block.c > > +++ b/block.c > > @@ -84,6 +84,9 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, > > BdrvChildRole child_role, > > Error **errp); > > +static bool bdrv_recurse_has_child(BlockDriverState *bs, > > + BlockDriverState *child); > > + > > static void bdrv_replace_child_noperm(BdrvChild *child, > > BlockDriverState *new_bs); > > static void bdrv_remove_file_or_backing_child(BlockDriverState *bs, > > @@ -2673,6 +2676,7 @@ static void bdrv_replace_child_noperm(BdrvChild *child, > > int drain_saldo; > > assert(!child->frozen); > > + assert(old_bs != new_bs); > > if (old_bs && new_bs) { > > assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs)); > > @@ -2892,6 +2896,12 @@ static int bdrv_attach_child_noperm(BlockDriverState *parent_bs, > > assert(parent_bs->drv); > > + if (bdrv_recurse_has_child(child_bs, parent_bs)) { > > + error_setg(errp, "Making '%s' a %s child of '%s' would create a cycle", > > + parent_bs->node_name, child_name, child_bs->node_name); > > Seems, child_bs and parent_bs should be swapped. Oops, thanks. I'm fixing it up while applying. Kevin