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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 660DDC2D0DB for ; Mon, 20 Jan 2020 16:17:19 +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 2F12621D7E for ; Mon, 20 Jan 2020 16:17:19 +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="I9bjrYzL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2F12621D7E 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]:39324 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1itZjp-0000aq-99 for qemu-devel@archiver.kernel.org; Mon, 20 Jan 2020 11:17:18 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:56583) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1itZhb-0007ZR-FV for qemu-devel@nongnu.org; Mon, 20 Jan 2020 11:15:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1itZhX-0007pF-Ky for qemu-devel@nongnu.org; Mon, 20 Jan 2020 11:14:59 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:59880 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1itZhX-0007p7-Gx for qemu-devel@nongnu.org; Mon, 20 Jan 2020 11:14:55 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579536895; 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=r0I0KsyEoqcLE2wllXlOv7kDqQCIS7HD0QX2fSOULAM=; b=I9bjrYzL+ynv+h4uCyWhzIl089e7yYES66afMSwfJ/gnfWeJwmDLxnQv3Rz6J0k9ytBxSV ZOx2egpaUBPfkU/cOLKJLJfEh6VtoBK/8h3o2wqv1moj0uH/rtOx9bJZkUDUU8sOVZpmoU iJVUBrF+l/zw8dgtiLZvhy6xFwxwnIU= 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-131-MhHU-dqCPQujv80w2B7Ryw-1; Mon, 20 Jan 2020 11:14:51 -0500 X-MC-Unique: MhHU-dqCPQujv80w2B7Ryw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 32B4B8017CC; Mon, 20 Jan 2020 16:14:50 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-117-225.ams2.redhat.com [10.36.117.225]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A77D11001B2D; Mon, 20 Jan 2020 16:14:47 +0000 (UTC) Subject: Re: [PATCH v9 2/2] docs: qcow2: introduce compression type feature To: Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org References: <20191216121733.63562-1-vsementsov@virtuozzo.com> <20191216121733.63562-3-vsementsov@virtuozzo.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: Mon, 20 Jan 2020 17:14:45 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: <20191216121733.63562-3-vsementsov@virtuozzo.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="rpkMiUWNtrjlzTZLJyq66SqrmK9XioFwe" X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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, qemu-block@nongnu.org, armbru@redhat.com, dplotnikov@virtuozzo.com, den@openvz.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) --rpkMiUWNtrjlzTZLJyq66SqrmK9XioFwe Content-Type: multipart/mixed; boundary="GtNnekeSVsjO5Wg4z5nNl1eYwGWzgKZHn" --GtNnekeSVsjO5Wg4z5nNl1eYwGWzgKZHn Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 16.12.19 13:17, Vladimir Sementsov-Ogievskiy wrote: > The patch add new additional field to qcow2 header: compression_type, > which specifies compression type. If field is absent or zero, default > compression type is set: ZLIB, which corresponds to current behavior. >=20 > New compression type (ZSTD) is to be added in further commit. >=20 > Suggested-by: Denis Plotnikov > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > docs/interop/qcow2.txt | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) >=20 > diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt > index d92c827763..77146b5169 100644 > --- a/docs/interop/qcow2.txt > +++ b/docs/interop/qcow2.txt > @@ -109,6 +109,11 @@ the next fields through header_length. > An External Data File Name header extens= ion may > be present if this bit is set. > =20 > + Bit 3: Compression type bit. If this bit is se= t, > + non-default compression is used for comp= ressed s/non-default/a non-default/ > + clusters. compression_type field must be > + present and not zero. s/compression_type field/The compression_type field/ > + > Bits 3-63: Reserved (set to 0) > =20 > 80 - 87: compatible_features > @@ -188,7 +193,16 @@ present*, if not altered by specific incompatible bi= t. > *. Field is not present when header_length is less or equal to field's o= ffset. > Also, all additional fields are not present for version 2. > =20 > - < ... No additional fields in the header currently ... > > + 104: compression_type > + Defines the compression method used for compressed c= lusters. > + A single compression type is applied to all compress= ed image > + clusters. Sounds a bit too complicated. Maybe =84All compressed clusters in an image use the same compression type.=94 instead? (Or s/an/the same/) > + If incompatible compression type bit is set: the fie= ld must Hmm, this sounds like there was an =93incompatible compression type=94 bit, instead of an incompatible bit called =93compression type=94. So maybe =93= If the incompatible bit "compression type" is set, this field must...=94? > + be present and non-zero (which means non-zlib compre= ssion type) s/$/./ > + If incompatible compression type bit is unset: the f= ield I=92d just make this =93Otherwise, this field...=94 > + may not exist or it must be zero (which means zlib). =93must not be present or must be zero=94? (=93exist=94 sounds a bit weird; the spec only defined =93not present=94 so= far. As for the =93may not=94, that isn=92t in RFC 2119. :-)) Max > + Available compression type values: > + 0: zlib > =20 > Header padding > =20 >=20 --GtNnekeSVsjO5Wg4z5nNl1eYwGWzgKZHn-- --rpkMiUWNtrjlzTZLJyq66SqrmK9XioFwe Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl4l0fUACgkQ9AfbAGHV z0BQawf/TZ5Vwe6iiMpoWTn/HMTGcfXAcTpUraQsNs9Qn3TwAsUxH5bDBbm9snzN kHVC1xJ4U5f10U1GSXrB9wXUoFhMPu4ECxLDBsMWseG2BAJQSgj1/m6RF2Muvt2s g2Bi7JS6eFyqIu8cVPRVW64YUGU26ybe8kV67HDxTXW6CZtWzoUPWEou3aaHLlVR oSP/H3t07pqjXUTvDpMWqoSGi5CPPiM8Lul7kCTnxwxYbhlW/Feeu0FvmsRyW3Pb 60TGovrF8pTpY8xPqjJFpw9ICOV371ZgHnDKjm2kIksY1d4ckkSYPP9wazfj+ZJ1 Ocvx/7kUxvUgrs0TCYt1QIRSt/19Fg== =IbpN -----END PGP SIGNATURE----- --rpkMiUWNtrjlzTZLJyq66SqrmK9XioFwe--