From patchwork Tue Nov 16 13:06:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 12622367 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 AE5C2C433F5 for ; Tue, 16 Nov 2021 13:35:49 +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 3A9B961B44 for ; Tue, 16 Nov 2021 13:35:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3A9B961B44 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]:33330 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mmycg-00025O-OX for qemu-devel@archiver.kernel.org; Tue, 16 Nov 2021 08:35:43 -0500 Received: from eggs.gnu.org ([209.51.188.92]:60174) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mmyD4-0007J0-PE for qemu-devel@nongnu.org; Tue, 16 Nov 2021 08:09:15 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:38225) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mmyD2-0007Mj-TF for qemu-devel@nongnu.org; Tue, 16 Nov 2021 08:09:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1637068152; 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=nev6fyeldn+IEwMjHlHF+B7kJv0EQKHzF2xnCOHBGyA=; b=SQWd6TyXMo6xOcX9wIWkPI7Yec9KozN06Ka5aX38WdZDYjIrWvF+ImV66Yap6pYlZ/et3Q mFEtOnrUNGwf/mqxpxS8wNH7tR+ZyhmY4tD/TxLX+/H6N4ojY5vCB3lrPXQPEkcNRwEX0V iwIdNEtAXPrlensToG7y4KL2xvRP2iY= 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-281-w6w70SUIMfyD_1GfWxe1qQ-1; Tue, 16 Nov 2021 08:06:24 -0500 X-MC-Unique: w6w70SUIMfyD_1GfWxe1qQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EDB7F879A07; Tue, 16 Nov 2021 13:06:22 +0000 (UTC) Received: from localhost (unknown [10.39.192.139]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 91F2A60C13; Tue, 16 Nov 2021 13:06:22 +0000 (UTC) From: Hanna Reitz To: qemu-block@nongnu.org Subject: [PULL v2 01/13] stream: Traverse graph after modification Date: Tue, 16 Nov 2021 14:06:06 +0100 Message-Id: <20211116130618.700441-2-hreitz@redhat.com> In-Reply-To: <20211116130618.700441-1-hreitz@redhat.com> References: <20211116130618.700441-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=hreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.129.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.697, 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_H4=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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Peter Maydell , Hanna Reitz , Richard Henderson , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" bdrv_cor_filter_drop() modifies the block graph. That means that other parties can also modify the block graph before it returns. Therefore, we cannot assume that the result of a graph traversal we did before remains valid afterwards. We should thus fetch `base` and `unfiltered_base` afterwards instead of before. Signed-off-by: Hanna Reitz Reviewed-by: Kevin Wolf Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <20211111120829.81329-2-hreitz@redhat.com> Signed-off-by: Kevin Wolf Message-Id: <20211115145409.176785-2-kwolf@redhat.com> Signed-off-by: Hanna Reitz --- block/stream.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/block/stream.c b/block/stream.c index 97bee482dc..e45113aed6 100644 --- a/block/stream.c +++ b/block/stream.c @@ -54,8 +54,8 @@ static int stream_prepare(Job *job) { StreamBlockJob *s = container_of(job, StreamBlockJob, common.job); BlockDriverState *unfiltered_bs = bdrv_skip_filters(s->target_bs); - BlockDriverState *base = bdrv_filter_or_cow_bs(s->above_base); - BlockDriverState *unfiltered_base = bdrv_skip_filters(base); + BlockDriverState *base; + BlockDriverState *unfiltered_base; Error *local_err = NULL; int ret = 0; @@ -63,6 +63,9 @@ static int stream_prepare(Job *job) bdrv_cor_filter_drop(s->cor_filter_bs); s->cor_filter_bs = NULL; + base = bdrv_filter_or_cow_bs(s->above_base); + unfiltered_base = bdrv_skip_filters(base); + if (bdrv_cow_child(unfiltered_bs)) { const char *base_id = NULL, *base_fmt = NULL; if (unfiltered_base) {