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spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:54378 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1knmsT-0002O5-AH for qemu-devel@archiver.kernel.org; Fri, 11 Dec 2020 13:10:49 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:53902) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1knm6j-0000rR-PU for qemu-devel@nongnu.org; Fri, 11 Dec 2020 12:21:29 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:44039) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1knm6h-00070o-Df for qemu-devel@nongnu.org; Fri, 11 Dec 2020 12:21:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607707286; 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=1a7jRgN6EDHHtr30+VpGBj0+vBVKrsLqKpbF+8gWhsA=; b=S3yZ+3l/3xaDhW9D7g3wNoRniKUaVAYMuE7vKAchTcHo1H1U6HS1AGPUwfcxGrrO4U1ND4 e1kdsx7Lht2plB772OUH97TH3izUGNC5dyizxbSOTWPBdirTiBahjn4yxnKRQXsYIWwpoS KCBNiwabny2tGTATvA+H9oUW0vMdosg= 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-414-1Anh4zB0Oey-Ssnt0t2ObA-1; Fri, 11 Dec 2020 12:21:24 -0500 X-MC-Unique: 1Anh4zB0Oey-Ssnt0t2ObA-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 3D2CD180A09C; Fri, 11 Dec 2020 17:21:23 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-112-98.ams2.redhat.com [10.36.112.98]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C00E65F9B7; Fri, 11 Dec 2020 17:21:11 +0000 (UTC) Subject: Re: [PATCH v14 13/13] block: apply COR-filter to block-stream jobs To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20201204220758.2879-1-vsementsov@virtuozzo.com> <20201204220758.2879-14-vsementsov@virtuozzo.com> From: Max Reitz Message-ID: <6aa8bbb7-6745-eed3-ade6-3ef47d5ee08d@redhat.com> Date: Fri, 11 Dec 2020 18:21:09 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <20201204220758.2879-14-vsementsov@virtuozzo.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=63.128.21.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_NONE=-0.0001, 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: fam@euphon.net, kwolf@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, stefanha@redhat.com, andrey.shinkevich@virtuozzo.com, den@openvz.org, jsnow@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 04.12.20 23:07, Vladimir Sementsov-Ogievskiy wrote: > From: Andrey Shinkevich > > This patch completes the series with the COR-filter applied to > block-stream operations. > > Adding the filter makes it possible in future implement discarding > copied regions in backing files during the block-stream job, to reduce > the disk overuse (we need control on permissions). > > Also, the filter now is smart enough to do copy-on-read with specified > base, so we have benefit on guest reads even when doing block-stream of > the part of the backing chain. > > Several iotests are slightly modified due to filter insertion. > > Signed-off-by: Andrey Shinkevich > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > block/stream.c | 78 ++++++++++++++++++++++++++------------ > tests/qemu-iotests/030 | 8 ++-- > tests/qemu-iotests/141.out | 2 +- > tests/qemu-iotests/245 | 20 ++++++---- > 4 files changed, 72 insertions(+), 36 deletions(-) > > diff --git a/block/stream.c b/block/stream.c > index a7fd8945ad..b92f7de55b 100644 > --- a/block/stream.c > +++ b/block/stream.c [...] > @@ -295,17 +287,49 @@ void stream_start(const char *job_id, BlockDriverState *bs, [...] > + opts = qdict_new(); > + > + qdict_put_str(opts, "driver", "copy-on-read"); > + qdict_put_str(opts, "file", bdrv_get_node_name(bs)); > + /* Pass the base_overlay node name as 'bottom' to COR driver */ > + qdict_put_str(opts, "bottom", base_overlay->node_name); Hm. Should we set this option even if no base was specified? On one hand, omitting this option would cor_co_preadv_part() a bit quicker. On the other, what happens when you add a backing file below the bottom node during streaming (yes, a largely theoretical case)... Now, all data from it is ignored. That seemed a bit strange to me at first, but on second thought, it makes more sense. Doing anything else would produce a garbage result basically, because stream_run() doesn’t take such a change into account. So... After all I think I agree with setting @bottom unconditionally. And that’s the only comment I had. :) Reviewed-by: Max Reitz