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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 D8714C4CEC4 for ; Wed, 18 Sep 2019 19:58:53 +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 ABAE8222D0 for ; Wed, 18 Sep 2019 19:58:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ABAE8222D0 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]:34802 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAg6G-0005gG-Iy for qemu-devel@archiver.kernel.org; Wed, 18 Sep 2019 15:58:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36769) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAg5B-00055J-HL for qemu-devel@nongnu.org; Wed, 18 Sep 2019 15:57:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iAg5A-0006Ff-6t for qemu-devel@nongnu.org; Wed, 18 Sep 2019 15:57:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36210) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iAg55-0006AC-3U; Wed, 18 Sep 2019 15:57:39 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 469CF307D88C; Wed, 18 Sep 2019 19:57:35 +0000 (UTC) Received: from [10.10.124.73] (ovpn-124-73.rdu2.redhat.com [10.10.124.73]) by smtp.corp.redhat.com (Postfix) with ESMTP id 14E8C6012E; Wed, 18 Sep 2019 19:57:33 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20190917160731.10895-1-vsementsov@virtuozzo.com> <20190917160731.10895-2-vsementsov@virtuozzo.com> From: John Snow Message-ID: <4122264a-f7db-8b76-6930-87e2287c49b8@redhat.com> Date: Wed, 18 Sep 2019 15:57:33 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.0 MIME-Version: 1.0 In-Reply-To: <20190917160731.10895-2-vsementsov@virtuozzo.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Wed, 18 Sep 2019 19:57:35 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v12 1/2] block/backup: fix max_transfer handling for copy_range 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, mreitz@redhat.com, qemu-devel@nongnu.org, qemu-stable@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 9/17/19 12:07 PM, Vladimir Sementsov-Ogievskiy wrote: > Of course, QEMU_ALIGN_UP is a typo, it should be QEMU_ALIGN_DOWN, as we > are trying to find aligned size which satisfy both source and target. > Also, don't ignore too small max_transfer. In this case seems safer to > disable copy_range. > > Fixes: 9ded4a0114968e > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > block/backup.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/block/backup.c b/block/backup.c > index 763f0d7ff6..d8fdbfadfe 100644 > --- a/block/backup.c > +++ b/block/backup.c > @@ -741,12 +741,16 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, > job->cluster_size = cluster_size; > job->copy_bitmap = copy_bitmap; > copy_bitmap = NULL; > - job->use_copy_range = !compress; /* compression isn't supported for it */ > job->copy_range_size = MIN_NON_ZERO(blk_get_max_transfer(job->common.blk), > blk_get_max_transfer(job->target)); > - job->copy_range_size = MAX(job->cluster_size, > - QEMU_ALIGN_UP(job->copy_range_size, > - job->cluster_size)); > + job->copy_range_size = QEMU_ALIGN_DOWN(job->copy_range_size, > + job->cluster_size); > + /* > + * Compression is not supported for copy_range. Also, we don't want to > + * handle small max_transfer for copy_range (which currently don't > + * handle max_transfer at all). > + */ > + job->use_copy_range = !compress && job->copy_range_size > 0; > > /* Required permissions are already taken with target's blk_new() */ > block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL, > I'm clear on the alignment fix, I'm not clear on the comment about max_transfer and how it relates to copy_range_size being non-zero. "small max transfer" -- what happens when it's zero? we're apparently OK with a single cluster, but when it's zero, what happens?