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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A67EBC433EF for ; Wed, 6 Oct 2021 21:26:51 +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 265246105A for ; Wed, 6 Oct 2021 21:26:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 265246105A 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]:57648 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mYER7-0006j9-Q8 for qemu-devel@archiver.kernel.org; Wed, 06 Oct 2021 17:26:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48856) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mYEPA-0005qD-Hb for qemu-devel@nongnu.org; Wed, 06 Oct 2021 17:24:48 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:20333) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mYEP6-00046Y-Sh for qemu-devel@nongnu.org; Wed, 06 Oct 2021 17:24:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633555483; 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=RAqmOb2yz+BQpzsPsRPm7SYDS33UclCBn1mUB2pLj1Y=; b=g/fJAAsk4BGkLPdc6hx7d7qluoAIT2DACh+TCTscjni0NE1T0xdOYIJaACovLGc8CIqqor 2lRTOS4Rk8uWbLi4wkm++p7I0RhltQv5RFGDWhPrlvP/d4EBlFRLTq4rlSdWrmOrcE/HLw 2T4r45AFr2/lsYoTGx+k3I9eomUFKh0= 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-364-YuXBatdsM9yYY-R2HSTRvQ-1; Wed, 06 Oct 2021 17:24:42 -0400 X-MC-Unique: YuXBatdsM9yYY-R2HSTRvQ-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 3085881431D; Wed, 6 Oct 2021 21:24:41 +0000 (UTC) Received: from redhat.com (ovpn-113-79.phx2.redhat.com [10.3.113.79]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 817595C1C5; Wed, 6 Oct 2021 21:24:37 +0000 (UTC) Date: Wed, 6 Oct 2021 16:24:36 -0500 From: Eric Blake To: Hanna Reitz Subject: Re: [PATCH v5 08/13] job: Add job_cancel_requested() Message-ID: <20211006212436.jcekhpvx3i72fsns@redhat.com> References: <20211006151940.214590-1-hreitz@redhat.com> <20211006151940.214590-9-hreitz@redhat.com> MIME-Version: 1.0 In-Reply-To: <20211006151940.214590-9-hreitz@redhat.com> User-Agent: NeoMutt/20210205-815-1dd940 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=eblake@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=-0.05, 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_H2=-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 , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Oct 06, 2021 at 05:19:35PM +0200, Hanna Reitz wrote: > 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 Is this reference still accurate with the addition of new patch 7? > cancellation request as a request for immediate termination), and add > job_cancel_requested() 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. > > Finally, here is a justification for how different job_is_cancelled() > invocations are treated by this patch: ... > - job_update_rc(), job_finalize_single(), job_finish_sync(): These > functions are all called after the job has left its main loop. The > mirror job (the only job that can be soft-cancelled) will clear > .cancelled before leaving the main loop if it has been > soft-cancelled. Therefore, these functions will observe .cancelled > to be true only if the job has been force-cancelled. We can > continue to use job_is_cancelled(). > (Furthermore, conceptually, a soft-cancelled mirror job should not > report to have been cancelled. It should report completion (see > also the block-job-cancel QAPI documentation). Therefore, it makes > sense for these functions not to distinguish between a > soft-cancelled mirror job and a job that has completed as normal.) Thanks for the careful explanation. > > Buglink: https://gitlab.com/qemu-project/qemu/-/issues/462 > Signed-off-by: Hanna Reitz > --- > include/qemu/job.h | 8 +++++++- > block/mirror.c | 10 ++++------ > job.c | 14 ++++++++++++-- > 3 files changed, 23 insertions(+), 9 deletions(-) The commit message is loads longer than the patch itself, but for good reason. Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org