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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 7C843C433FF for ; Fri, 9 Aug 2019 13:06:30 +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 515A42086A for ; Fri, 9 Aug 2019 13:06:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 515A42086A 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]:59326 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hw4bF-0001MK-KC for qemu-devel@archiver.kernel.org; Fri, 09 Aug 2019 09:06:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53819) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hw4Ou-00044R-Bo for qemu-devel@nongnu.org; Fri, 09 Aug 2019 08:53:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hw4Ot-0004Bo-Ak for qemu-devel@nongnu.org; Fri, 09 Aug 2019 08:53:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49308) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hw4Or-0004A7-2s; Fri, 09 Aug 2019 08:53:41 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 62966308FFB1; Fri, 9 Aug 2019 12:53:40 +0000 (UTC) Received: from dresden.str.redhat.com (unknown [10.40.205.179]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 46F455D9D3; Fri, 9 Aug 2019 12:53:33 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , "qemu-block@nongnu.org" References: <20190807080750.15950-1-vsementsov@virtuozzo.com> <20190807080750.15950-5-vsementsov@virtuozzo.com> <23fd227d-9074-3a9e-b6c7-09f4abadc021@redhat.com> <7783cb6f-4e71-c789-3105-4a6dc3b1533d@virtuozzo.com> From: Max Reitz Openpgp: preference=signencrypt Autocrypt: addr=mreitz@redhat.com; prefer-encrypt=mutual; keydata= mQENBFXOJlcBCADEyyhOTsoa/2ujoTRAJj4MKA21dkxxELVj3cuILpLTmtachWj7QW+TVG8U /PsMCFbpwsQR7oEy8eHHZwuGQsNpEtNC2G/L8Yka0BIBzv7dEgrPzIu+W3anZXQW4702+uES U29G8TP/NGfXRRHGlbBIH9KNUnOSUD2vRtpOLXkWsV5CN6vQFYgQfFvmp5ZpPeUe6xNplu8V mcTw8OSEDW/ZnxJc8TekCKZSpdzYoxfzjm7xGmZqB18VFwgJZlIibt1HE0EB4w5GsD7x5ekh awIe3RwoZgZDLQMdOitJ1tUc8aqaxvgA4tz6J6st8D8pS//m1gAoYJWGwwIVj1DjTYLtABEB AAG0HU1heCBSZWl0eiA8bXJlaXR6QHJlZGhhdC5jb20+iQFTBBMBCAA9AhsDBQkSzAMABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheABQJVzie5FRhoa3A6Ly9rZXlzLmdudXBnLm5ldAAKCRD0 B9sAYdXPQDcIB/9uNkbYEex1rHKz3mr12uxYMwLOOFY9fstP5aoVJQ1nWQVB6m2cfKGdcRe1 2/nFaHSNAzT0NnKz2MjhZVmcrpyd2Gp2QyISCfb1FbT82GMtXFj1wiHmPb3CixYmWGQUUh+I AvUqsevLA+WihgBUyaJq/vuDVM1/K9Un+w+Tz5vpeMidlIsTYhcsMhn0L9wlCjoucljvbDy/ 8C9L2DUdgi3XTa0ORKeflUhdL4gucWoAMrKX2nmPjBMKLgU7WLBc8AtV+84b9OWFML6NEyo4 4cP7cM/07VlJK53pqNg5cHtnWwjHcbpGkQvx6RUx6F1My3y52vM24rNUA3+ligVEgPYBuQEN BFXOJlcBCADAmcVUNTWT6yLWQHvxZ0o47KCP8OcLqD+67T0RCe6d0LP8GsWtrJdeDIQk+T+F xO7DolQPS6iQ6Ak2/lJaPX8L0BkEAiMuLCKFU6Bn3lFOkrQeKp3u05wCSV1iKnhg0UPji9V2 W5eNfy8F4ZQHpeGUGy+liGXlxqkeRVhLyevUqfU0WgNqAJpfhHSGpBgihUupmyUg7lfUPeRM DzAN1pIqoFuxnN+BRHdAecpsLcbR8sQddXmDg9BpSKozO/JyBmaS1RlquI8HERQoe6EynJhd 64aICHDfj61rp+/0jTIcevxIIAzW70IadoS/y3DVIkuhncgDBvGbF3aBtjrJVP+5ABEBAAGJ ASUEGAEIAA8FAlXOJlcCGwwFCRLMAwAACgkQ9AfbAGHVz0CbFwf9F/PXxQR9i4N0iipISYjU sxVdjJOM2TMut+ZZcQ6NSMvhZ0ogQxJ+iEQ5OjnIputKvPVd5U7WRh+4lF1lB/NQGrGZQ1ic alkj6ocscQyFwfib+xIe9w8TG1CVGkII7+TbS5pXHRxZH1niaRpoi/hYtgzkuOPp35jJyqT/ /ELbqQTDAWcqtJhzxKLE/ugcOMK520dJDeb6x2xVES+S5LXby0D4juZlvUj+1fwZu+7Io5+B bkhSVPb/QdOVTpnz7zWNyNw+OONo1aBUKkhq2UIByYXgORPFnbfMY7QWHcjpBVw9MgC4tGeF R4bv+1nAMMxKmb5VvQCExr0eFhJUAHAhVg== Message-ID: <07f45d08-33dd-b49c-6a71-58fc84876697@redhat.com> Date: Fri, 9 Aug 2019 14:53:31 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <7783cb6f-4e71-c789-3105-4a6dc3b1533d@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="RDR7tmmdkpJoXjrrv67ZiGAbadZDnNvkn" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Fri, 09 Aug 2019 12:53:40 +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 4/8] block/backup: improve unallocated clusters skipping 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" , Denis Lunev , "qemu-devel@nongnu.org" , "armbru@redhat.com" , "stefanha@redhat.com" , "jsnow@redhat.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --RDR7tmmdkpJoXjrrv67ZiGAbadZDnNvkn Content-Type: multipart/mixed; boundary="846srVejgHDJbo1MgXslFWaJt5okTOadu"; protected-headers="v1" From: Max Reitz To: Vladimir Sementsov-Ogievskiy , "qemu-block@nongnu.org" Cc: "qemu-devel@nongnu.org" , "armbru@redhat.com" , "fam@euphon.net" , "stefanha@redhat.com" , "kwolf@redhat.com" , "jsnow@redhat.com" , Denis Lunev Message-ID: <07f45d08-33dd-b49c-6a71-58fc84876697@redhat.com> Subject: Re: [PATCH 4/8] block/backup: improve unallocated clusters skipping References: <20190807080750.15950-1-vsementsov@virtuozzo.com> <20190807080750.15950-5-vsementsov@virtuozzo.com> <23fd227d-9074-3a9e-b6c7-09f4abadc021@redhat.com> <7783cb6f-4e71-c789-3105-4a6dc3b1533d@virtuozzo.com> In-Reply-To: <7783cb6f-4e71-c789-3105-4a6dc3b1533d@virtuozzo.com> --846srVejgHDJbo1MgXslFWaJt5okTOadu Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 09.08.19 14:47, Vladimir Sementsov-Ogievskiy wrote: > 09.08.2019 15:25, Max Reitz wrote: >> On 09.08.19 09:50, Vladimir Sementsov-Ogievskiy wrote: >>> 07.08.2019 21:01, Max Reitz wrote: >>>> On 07.08.19 10:07, Vladimir Sementsov-Ogievskiy wrote: >>>>> Limit block_status querying to request bounds on write notifier to >>>>> avoid extra seeking. >>>> >>>> I don=E2=80=99t understand this reasoning. Checking whether somethi= ng is >>>> allocated for qcow2 should just mean an L2 cache lookup. Which we h= ave >>>> to do anyway when we try to copy data off the source. >>> >>> But for raw it's seeking. >> >> (1) That=E2=80=99s a bug in block_status then, isn=E2=80=99t it? >> >> file-posix cannot determine the allocation status, or rather, everythi= ng >> is allocated. bdrv_co_block_status() should probably pass @want_zero = on >> to the driver=E2=80=99s implementation, and file-posix should just >> unconditionally return DATA if it=E2=80=99s false. >> >> (2) Why would you even use sync=3Dtop for raw nodes? >> >=20 > As I described in parallel letters, raw was bad example. NBD is good. Does NBD support backing files? > Anyway, now I'm refactoring cluster skipping more deeply for v2. >=20 > About top-mode: finally block-status should be used to improve other > modes too. In virtuozzo we skip unallocated for full mode too, for exam= ple. But this patch here is about sync=3Dtop. Skipping is an optimization, the block_status querying here happens because copying anything that isn=E2=80=99t allocated in the top layer wo= uld be wrong. Max > Unfortunately, backup is most long-term thing to upstream for me.. --846srVejgHDJbo1MgXslFWaJt5okTOadu-- --RDR7tmmdkpJoXjrrv67ZiGAbadZDnNvkn Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl1NbMsACgkQ9AfbAGHV z0CyKwf9EwKWp0iQMIAC4lu0Bb6YkkUTZzCQ2cj4Zq7m07fel4CX+zOFmmqc7fPS II2Qc8vMAtL/lWMWc53iVYscIi3txqtp0bEeRc9moXWevAC+phpqxMHdntlHQJnI n/eXl2W2UWKmr1cwBWmt7ebywQMguvdrK3G5m2n5A4Y6AoUZFQ1zt8WkSxMalfCT CrXZuOyPl0YgsvFVpdKz4o8Q5JOvYCHLX8P2g2J1J+73dZH1gZXe6aAPlBw4gok3 /XP/dWRLaJNMp55ykPLLlo9XAcpeTJpaCJx8dUJ/6RjIvBHho89KsIF/WrR6XXLe RtAPdiqyY+wi243chB0Pg+TA3yigFQ== =mYi8 -----END PGP SIGNATURE----- --RDR7tmmdkpJoXjrrv67ZiGAbadZDnNvkn--