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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 63A9FC433ED for ; Fri, 16 Apr 2021 07:12:36 +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 A3E91610CC for ; Fri, 16 Apr 2021 07:12:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A3E91610CC 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]:55596 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lXIeY-0007P7-E7 for qemu-devel@archiver.kernel.org; Fri, 16 Apr 2021 03:12:34 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47190) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lXIdM-0006lF-Hh for qemu-devel@nongnu.org; Fri, 16 Apr 2021 03:11:20 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:40793) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lXIdK-0004p4-1Y for qemu-devel@nongnu.org; Fri, 16 Apr 2021 03:11:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618557077; 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=9bi06xcak41WEfg6uAzy/+N11jZ+D6OSUzpk3DrcL40=; b=GT5REdiDeTtyj5yDD2lN4TWz63VcPyZgE1R6hruZQwdsQzYXuQTqtwPsbBytGSh7ex0UFo KrL0G0FSmKjy6q5Me5VEvcMJIeCsOhdXZGLWdmgi4cEptGjb+B4KoR5GtP5Uc6F/hAA2lE zTlB70tp9PCernLZJO30D2ZuRs8wuVc= 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-96-az_St-pYPiy14tJ1PJP9nA-1; Fri, 16 Apr 2021 03:11:15 -0400 X-MC-Unique: az_St-pYPiy14tJ1PJP9nA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4ADC16D246; Fri, 16 Apr 2021 07:11:14 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-113-131.ams2.redhat.com [10.36.113.131]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DBC7F5E1A4; Fri, 16 Apr 2021 07:11:12 +0000 (UTC) Subject: Re: about mirror cancel From: Max Reitz To: Vladimir Sementsov-Ogievskiy , qemu block References: <5df8166f-a204-6510-e27a-1b334f0bb3f3@redhat.com> Message-ID: Date: Fri, 16 Apr 2021 09:11:11 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <5df8166f-a204-6510-e27a-1b334f0bb3f3@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=mreitz@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, NICE_REPLY_A=-0.001, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , "Denis V. Lunev" , qemu-devel Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 16.04.21 09:05, Max Reitz wrote: > On 15.04.21 20:46, Vladimir Sementsov-Ogievskiy wrote: [...] >> Note, that if cancelling all in-flight requests on target is wrong on >> mirror cancel, we still don't have real bug, as the only >> implementation of .bdrv_cancel_in_flight is stopping reconnect waiting >> in nbd driver. So, we'll cancel requests only if connection is already >> lost anyway. >> >> But that probably means, that correct name of the handler would be >> .bdrv_cancel_in_fligth_requests_that_will_most_probably_fail_anyway().. > > It’s documentation states that it should cancel all in-flight requests, > so it’s more likely it just isn’t implemented where it could be. Oh, I now see you added it in the same series. Well, then I suppose you’re free to change the semantics as you see fit. But be aware that even cancelling those requests means that you abandon the target. So it must then fail instead of emitting the COMPLETED event (AFAIR the mirror job emits COMPLETED when cancelled in READY with force=false). If the user wants the mirror job to create a consistent copy and so cancels it after READY (with force=false), I don’t know whether cancelling those hanging requests is what we want. If the cancel hangs and the user sees this, they are still free to decide to cancel again with force=true, no? Max