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=-5.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,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 68F34C433DF for ; Thu, 2 Jul 2020 11:32:23 +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 35E4920723 for ; Thu, 2 Jul 2020 11:32:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bTCJ6QMZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 35E4920723 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]:37096 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jqxS2-0005ZZ-G0 for qemu-devel@archiver.kernel.org; Thu, 02 Jul 2020 07:32:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58636) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jqxQQ-0003Je-SJ for qemu-devel@nongnu.org; Thu, 02 Jul 2020 07:30:42 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:31290 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jqxQN-0001AZ-E3 for qemu-devel@nongnu.org; Thu, 02 Jul 2020 07:30:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593689438; 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:autocrypt:autocrypt; bh=xdTj48wOCCSQvdOMkIxAXeO3zn0KZTpuVZBy3piIOM4=; b=bTCJ6QMZbjqhaekYG5Kom1Q/4QxoCGF90B+muCq4KMpfm2F+k11jlQ20jJp2a/ycZ+iQRw byaD5TeceBhoF6z32p4zl6QvKqs78a6qNuSbTeRfSglE2crYYYIt92ISFmn7txtxdqi9Hk ao96CQj7hZTwKZhMpatoJciSr2Tt0KM= 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-385-P0idx3HuO4Wxm0wd9gNuKg-1; Thu, 02 Jul 2020 07:30:31 -0400 X-MC-Unique: P0idx3HuO4Wxm0wd9gNuKg-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 4EC1A18FF660; Thu, 2 Jul 2020 11:30:30 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-113-196.ams2.redhat.com [10.36.113.196]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 51BFD5C1D0; Thu, 2 Jul 2020 11:30:28 +0000 (UTC) Subject: Re: [PATCH v9 20/34] qcow2: Add subcluster support to calculate_l2_meta() To: Alberto Garcia , qemu-devel@nongnu.org References: <12ee527c0e8a80694fd249a38f106927062e3b44.1593342067.git.berto@igalia.com> From: Max Reitz 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: Date: Thu, 2 Jul 2020 13:30:26 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <12ee527c0e8a80694fd249a38f106927062e3b44.1593342067.git.berto@igalia.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: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Yd6xTUyvZ53jQcO7GWf6YoygiWLMpyOdN" Received-SPF: pass client-ip=207.211.31.120; envelope-from=mreitz@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/02 03:23:40 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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 , Derek Su , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org 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) --Yd6xTUyvZ53jQcO7GWf6YoygiWLMpyOdN Content-Type: multipart/mixed; boundary="69Wq9Jg3hXZ3vSoF0Uy7d6GdN0yP0iXES" --69Wq9Jg3hXZ3vSoF0Uy7d6GdN0yP0iXES Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 28.06.20 13:02, Alberto Garcia wrote: > If an image has subclusters then there are more copy-on-write > scenarios that we need to consider. Let's say we have a write request > from the middle of subcluster #3 until the end of the cluster: >=20 > 1) If we are writing to a newly allocated cluster then we need > copy-on-write. The previous contents of subclusters #0 to #3 must > be copied to the new cluster. We can optimize this process by > skipping all leading unallocated or zero subclusters (the status of > those skipped subclusters will be reflected in the new L2 bitmap). >=20 > 2) If we are overwriting an existing cluster: >=20 > 2.1) If subcluster #3 is unallocated or has the all-zeroes bit set > then we need copy-on-write (on subcluster #3 only). >=20 > 2.2) If subcluster #3 was already allocated then there is no need > for any copy-on-write. However we still need to update the L2 > bitmap to reflect possible changes in the allocation status of > subclusters #4 to #31. Because of this, this function checks > if all the overwritten subclusters are already allocated and > in this case it returns without creating a new QCowL2Meta > structure. >=20 > After all these changes l2meta_cow_start() and l2meta_cow_end() > are not necessarily cluster-aligned anymore. We need to update the > calculation of old_start and old_end in handle_dependencies() to > guarantee that no two requests try to write on the same cluster. >=20 > Signed-off-by: Alberto Garcia > Reviewed-by: Eric Blake > --- > block/qcow2-cluster.c | 163 +++++++++++++++++++++++++++++++++--------- > 1 file changed, 131 insertions(+), 32 deletions(-) Reviewed-by: Max Reitz --69Wq9Jg3hXZ3vSoF0Uy7d6GdN0yP0iXES-- --Yd6xTUyvZ53jQcO7GWf6YoygiWLMpyOdN Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl79xVIACgkQ9AfbAGHV z0DSgwf+PNuM4Tl3mJzA6pCnIY8WReX1F0lg8bTVqL485E9rYen1TCTqO1oludGD KnSmED2QUERPCHalSUF6bN3CAu3OPvr1iHVNAkNQV0mV6MYNZBi03+Iyn+4YBFCx ccyAP+MtWsRDujAT5XE70Yr7/cqtAyjR2Vmh0rsHXKdMPH967Q+Xt7Sb4yK0SUEm QDRB8SXBXBAgRH7UdkRD8ErvYREuTdKA9BfkPxGR1Ec1+LyoU6o8zQlx/1t4ziXR qINGTzsAY3y3YN38I9OiUKwemNM/TSTyPRMdklI3DJtkl5UYjRv1yfwNKvNUm0Na qT5/GjHxH0lXmvA4nIppWisxCUMHsA== =4Dci -----END PGP SIGNATURE----- --Yd6xTUyvZ53jQcO7GWf6YoygiWLMpyOdN--