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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 D0656C432C3 for ; Fri, 15 Nov 2019 08:10:16 +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 5881B20729 for ; Fri, 15 Nov 2019 08:10:16 +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="EgRnyfcy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5881B20729 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]:36505 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iVWgJ-00050y-8B for qemu-devel@archiver.kernel.org; Fri, 15 Nov 2019 03:10:15 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:40584) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iVWe7-0002mQ-El for qemu-devel@nongnu.org; Fri, 15 Nov 2019 03:08:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iVWe5-0002FN-0j for qemu-devel@nongnu.org; Fri, 15 Nov 2019 03:07:58 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:52771 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 1iVWe4-0002D6-Kh for qemu-devel@nongnu.org; Fri, 15 Nov 2019 03:07:56 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573805273; 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=rrvg7CgO7jlaQY7fHcK9rWZ8NGrl8vk+08jktZnHHYI=; b=EgRnyfcyhLH4v6Hqj3Q0OA7886XW4ciQzgoE4zoOwZd3jrxIR8Z5ska+QvM9vJvu0H0N0s IhU8xxKLRppcIh2xSkHXSJbulX6qnnD4ClgibPtEff7003NwrkqHgC42b1yOhhGeQK/Do+ JmvCAEOKa6Ox46J0ohN/f952hjvL110= 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-382-6LopJdKrMhqfynA3Rhlt3A-1; Fri, 15 Nov 2019 03:07:50 -0500 X-MC-Unique: 6LopJdKrMhqfynA3Rhlt3A-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 46E1A1005500; Fri, 15 Nov 2019 08:07:49 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-116-227.ams2.redhat.com [10.36.116.227]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1BA3E101E3CB; Fri, 15 Nov 2019 08:07:47 +0000 (UTC) Subject: Re: Convert VMDK to RAW To: janine.schneider@fau.de References: <009201d59b06$475883f0$d6098bd0$@fau.de> <97e53c9c-7d3d-75e7-8227-7a1ff186f52e@redhat.com> <000401d59b12$8024ce30$806e6a90$@fau.de> 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: Fri, 15 Nov 2019 09:07:45 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <000401d59b12$8024ce30$806e6a90$@fau.de> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="hhXRofxlm1xBcIPaanr95f2TjqFmOfONQ" X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 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: "qemu-devel@nongnu.org" , Qemu-block 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) --hhXRofxlm1xBcIPaanr95f2TjqFmOfONQ Content-Type: multipart/mixed; boundary="JysJtWR3vTNzwshA5XwuXQKSDBtzeU38Q" --JysJtWR3vTNzwshA5XwuXQKSDBtzeU38Q Content-Type: text/plain; charset=WINDOWS-1252 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 14.11.19 18:39, janine.schneider@fau.de wrote: > Hello, >=20 > thank you for the quick feedback. I am sorry that I expressed myself so > unclearly. I don't want to use qemu but want to know how qemu converts vm= dk > to raw. So how exactly is the conversion programmed? How are the sparse > grains put together to get an uncompressed virtual disk? I am a programme= r > and would like to reimplement this function. I already looked at the qemu > code, but couldn't figure out how the conversion works. Oh, OK. Well, even (or maybe especially) programmers sometimes want to reuse existing functionality, so I assumed it would be sufficient for you to just use qemu tools. ;-) (For example, qemu-nbd allows presenting a VMDK image as a local block device that you can randomly access.) The code to interpret the VMDK format is in block/vmdk.c. The function to read an arbitrary guest offset of the disk image is vmdk_co_preadv(). The conversion just iterates over the whole image and copies everything read with that function to the output image, so I don=92t think you need to look at anything but block/vmdk.c. vmdk_open() opens the image and thus parses the description file. I suppose (I=92m no expert in the VMDK code) of particular interest are vmdk_parse_extents() and anything that calls vmdk_add_extent(). These code paths create a list of all extent files. >From a quick look at vmdk_co_preadv(), find_extent() then looks up the corresponding extent file based on the guest offset; get_cluster_offset() looks up the file offset in that extent file for the respective guest offset; and vmdk_read_extent() then reads from the file at that offset, decompressing the data if necessary. (Note that https://www.vmware.com/support/developer/vddk/vmdk_50_technote.pdf probably understands the concepts of VMDK much better than I do *cough*) Max --JysJtWR3vTNzwshA5XwuXQKSDBtzeU38Q-- --hhXRofxlm1xBcIPaanr95f2TjqFmOfONQ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl3OXNEACgkQ9AfbAGHV z0CxOwf6A9Q0QrNbk/8+2AdXUUnx/u77RDeoMWe5D/AJ5EwLYm+CH/cRp9wnnag3 6zEALDmeMzRXkSqI7BjDeiw31DwkAQfsh76rYkL1kikTMdud5l5qsqV1fLY7Fd++ IrvFg73R8O6E+Wdrwh09RqBXVoO9b3nwqlX8ut0BVnlpHTE30ctIdfkA3HT064y1 UFAz9coIEbhkYQxLh4VpqXx/W2ze992VYVnvOUhR3GppbvbVbK7ZeHh9T8PSUZ0P 3jOqbAy7c3TaViGkyogrPw1ms040iXs2sdiO+tf4MYc2u0mUVgXmfwTlg6YFayzv WrTfToxCXk17VidKVs9vzOASCFYweQ== =KOZT -----END PGP SIGNATURE----- --hhXRofxlm1xBcIPaanr95f2TjqFmOfONQ--