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 X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1DD4BC4363D for ; Wed, 23 Sep 2020 15:18:54 +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 A4A522075B for ; Wed, 23 Sep 2020 15:18:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="G4ro5hbY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A4A522075B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:37932 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kL6Xk-0002CP-EG for qemu-devel@archiver.kernel.org; Wed, 23 Sep 2020 11:18:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34508) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kL6Ut-00008p-Tp for qemu-devel@nongnu.org; Wed, 23 Sep 2020 11:15:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:27757) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kL6Up-0004Vo-HZ for qemu-devel@nongnu.org; Wed, 23 Sep 2020 11:15:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600874150; 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=gYAUMPE9FYqbFMb0SXzDmxMSHkb4zKeANJeaxxi3qUY=; b=G4ro5hbY5spqR+sKXOPDwnOzj6kfiM18ZA9jUgxTiXKoAHDCTgoFMtIwrN6Hy5t0GpLdwL w8a21ZeunNWuHrRRqVJgFFvoHc6GufFtDAvhQp7w8lH3ZqQGC+fwEK20EdjLUdP+8fm13s t7E+QpVScuNTH0XOBTvr1SGsX+Z/ZXU= 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-585-v4AA2wcuOI-Ed9hmIgvptQ-1; Wed, 23 Sep 2020 11:15:48 -0400 X-MC-Unique: v4AA2wcuOI-Ed9hmIgvptQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 242FC8ECE58; Wed, 23 Sep 2020 15:15:47 +0000 (UTC) Received: from [10.3.114.2] (ovpn-114-2.phx2.redhat.com [10.3.114.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3342775120; Wed, 23 Sep 2020 15:15:44 +0000 (UTC) Subject: Re: [PATCH 3/4] block/nbd: fix reconnect-delay To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20200903190301.367620-1-vsementsov@virtuozzo.com> <20200903190301.367620-4-vsementsov@virtuozzo.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: Date: Wed, 23 Sep 2020 10:15:43 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200903190301.367620-4-vsementsov@virtuozzo.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Received-SPF: pass client-ip=216.205.24.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/22 23:02:20 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -32 X-Spam_score: -3.3 X-Spam_bar: --- X-Spam_report: (-3.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.228, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: kwolf@redhat.com, den@openvz.org, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 9/3/20 2:03 PM, Vladimir Sementsov-Ogievskiy wrote: > reconnect-delay has a design flaw: we handle it in the same loop where > we do connection attempt. So, reconnect-delay may be exceeded by > unpredictable time of connection attempt. > > Let's instead use separate timer. > > How to reproduce the bug: > > > This will make the connect() call of qemu-io at node2 take a long time. > > And you'll see that read command in qemu-io will hang for a long time, > more than 15 seconds specified by reconnect-delay parameter. It's the > bug. > > 8. Don't forget to drop iptables rule on node1: > > sudo iptables -D INPUT -p tcp --dport 10809 -j DROP > > Important note: Step [5] is necessary to reproduce _this_ bug. If we > miss step [5], the read command (step 6) will hang for a long time and > this commit doesn't help, because there will be not long connect() to > unreachable host, but long sendmsg() to unreachable host, which should > be fixed by enabling and adjusting keep-alive on the socket, which is a > thing for further patch set. > > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > block/nbd.c | 59 +++++++++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 50 insertions(+), 9 deletions(-) Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org