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=-18.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 61DEFC4338F for ; Tue, 3 Aug 2021 14:28:01 +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 F1A3C60BD3 for ; Tue, 3 Aug 2021 14:28:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org F1A3C60BD3 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]:33298 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mAvOi-0005u2-6y for qemu-devel@archiver.kernel.org; Tue, 03 Aug 2021 10:28:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59440) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mAvMC-00081R-5x for qemu-devel@nongnu.org; Tue, 03 Aug 2021 10:25:24 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:35278) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mAvM9-0001Fq-Gs for qemu-devel@nongnu.org; Tue, 03 Aug 2021 10:25:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628000720; 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=aemI1GdFWv9dfT8mhU27IANo6bvC0yu6VSAfW4Tgfbg=; b=XT9Gt7W9jhntPaypXXazSBl+VuaRa2XN8oU5cQK2rhPU1yMDtL9owq23WXljZpNb2Q5rIw TGEd7U1nXftJ7//kuVmbyw+qyNn6NIDaUxDq4mOSgbm6d88Oyk74nvb23vV0gMgC3LCvxU +E8gzkXcU9onNEvHnEIw/kVMLGpIMSE= 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-192-XI46M4DTPmqcAV0C7cw9-A-1; Tue, 03 Aug 2021 10:25:19 -0400 X-MC-Unique: XI46M4DTPmqcAV0C7cw9-A-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 B23041006C80; Tue, 3 Aug 2021 14:25:18 +0000 (UTC) Received: from redhat.com (unknown [10.39.193.5]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 91BFC5D6A8; Tue, 3 Aug 2021 14:25:17 +0000 (UTC) Date: Tue, 3 Aug 2021 16:25:16 +0200 From: Kevin Wolf To: Max Reitz Subject: Re: [PATCH for-6.1? v2 5/7] job: Add job_cancel_requested() Message-ID: References: <20210726144613.954844-1-mreitz@redhat.com> <20210726144613.954844-6-mreitz@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210726144613.954844-6-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.699, 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=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: Vladimir Sementsov-Ogievskiy , John Snow , qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 26.07.2021 um 16:46 hat Max Reitz geschrieben: > Most callers of job_is_cancelled() actually want to know whether the job > is on its way to immediate termination. For example, we refuse to pause > jobs that are cancelled; but this only makes sense for jobs that are > really actually cancelled. > > A mirror job that is cancelled during READY with force=false should > absolutely be allowed to pause. This "cancellation" (which is actually > a kind of completion) may take an indefinite amount of time, and so > should behave like any job during normal operation. For example, with > on-target-error=stop, the job should stop on write errors. (In > contrast, force-cancelled jobs should not get write errors, as they > should just terminate and not do further I/O.) > > Therefore, redefine job_is_cancelled() to only return true for jobs that > are force-cancelled (which as of HEAD^ means any job that interprets the > cancellation request as a request for immediate termination), and add > job_cancel_request() as the general variant, which returns true for any > jobs which have been requested to be cancelled, whether it be > immediately or after an arbitrarily long completion phase. > > Buglink: https://gitlab.com/qemu-project/qemu/-/issues/462 > Signed-off-by: Max Reitz > --- > include/qemu/job.h | 8 +++++++- > block/mirror.c | 10 ++++------ > job.c | 7 ++++++- > 3 files changed, 17 insertions(+), 8 deletions(-) > > diff --git a/include/qemu/job.h b/include/qemu/job.h > index 8aa90f7395..032edf3c5f 100644 > --- a/include/qemu/job.h > +++ b/include/qemu/job.h > @@ -436,9 +436,15 @@ const char *job_type_str(const Job *job); > /** Returns true if the job should not be visible to the management layer. */ > bool job_is_internal(Job *job); > > -/** Returns whether the job is scheduled for cancellation. */ > +/** Returns whether the job is being cancelled. */ > bool job_is_cancelled(Job *job); > > +/** > + * Returns whether the job is scheduled for cancellation (at an > + * indefinite point). > + */ > +bool job_cancel_requested(Job *job); I don't think non-force blockdev-cancel for mirror should actually be considered cancellation, so what is the question that this function answers? "Is this a cancelled job, or a mirror block job that is supposed to complete soon, but only if it doesn't switch over the users to the target on completion"? Is this ever a reasonable question to ask, except maybe inside the mirror implementation itself? job_complete() is the only function outside of mirror that seems to use it. But even there, it feels wrong to make a difference. Either we accept redundant completion requests, or we don't. It doesn't really matter how the job reconfigures the graph on completion. (Also, I feel this should really have been part of the state machine, but I'm not sure if we want to touch it now...) Kevin