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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 83EF3C433F5 for ; Tue, 26 Apr 2022 09:08:33 +0000 (UTC) Received: from localhost ([::1]:50522 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1njHBQ-0006ch-JN for qemu-devel@archiver.kernel.org; Tue, 26 Apr 2022 05:08:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43502) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1njGvF-0007DP-LO for qemu-devel@nongnu.org; Tue, 26 Apr 2022 04:51:49 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:53905) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1njGvE-0000gI-5i for qemu-devel@nongnu.org; Tue, 26 Apr 2022 04:51:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1650963107; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=t4QLXWHSEH+WUuRo1EdjW0OdX0UvC4rVVzDAZajucAM=; b=Unkg/6LAj0jaFNvjFnJejmsavOj/q7BH2yFiZAlHlY06SgmlduoHfNML57xib55xn0cVGU Yl7LRO4nRyRiDByJNF6Nm9R8XqJxwGiyjIFL8AQMq2XFlETD1X6SWwWU4kuXI+yqomv+ly PgFrc+6AMSpobGC7JOUO92zkRHo1fMk= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-294-wRp9yW_HMzWMkAT_eL3c1w-1; Tue, 26 Apr 2022 04:51:43 -0400 X-MC-Unique: wRp9yW_HMzWMkAT_eL3c1w-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 362CF29ABA05; Tue, 26 Apr 2022 08:51:32 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 11C5640E8100; Tue, 26 Apr 2022 08:51:25 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [RFC PATCH v2 8/8] mirror: protect drains in coroutine with rdlock Date: Tue, 26 Apr 2022 04:51:14 -0400 Message-Id: <20220426085114.199647-9-eesposit@redhat.com> In-Reply-To: <20220426085114.199647-1-eesposit@redhat.com> References: <20220426085114.199647-1-eesposit@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Received-SPF: pass client-ip=170.10.133.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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 , Fam Zheng , Vladimir Sementsov-Ogievskiy , Emanuele Giuseppe Esposito , qemu-devel@nongnu.org, Hanna Reitz , Stefan Hajnoczi , Paolo Bonzini , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Drain performed in coroutine schedules a bh in the main loop. However, drain itself still is a read, and we need to signal the writer that we are going through the graph. Signed-off-by: Emanuele Giuseppe Esposito --- block/mirror.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/block/mirror.c b/block/mirror.c index ce6bc58d1f..de86729f9b 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -1065,10 +1065,14 @@ static int coroutine_fn mirror_run(Job *job, Error **errp) trace_mirror_before_drain(s, cnt); s->in_drain = true; + bdrv_graph_co_rdlock(); bdrv_drained_begin(bs); + bdrv_graph_co_rdunlock(); cnt = bdrv_get_dirty_count(s->dirty_bitmap); if (cnt > 0 || mirror_flush(s) < 0) { + bdrv_graph_co_rdlock(); bdrv_drained_end(bs); + bdrv_graph_co_rdunlock(); s->in_drain = false; continue; } @@ -1110,7 +1114,9 @@ immediate_exit: if (need_drain) { s->in_drain = true; + bdrv_graph_co_rdlock(); bdrv_drained_begin(bs); + bdrv_graph_co_rdunlock(); } return ret; -- 2.31.1