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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 228F8C2BB85 for ; Tue, 14 Apr 2020 18:16:08 +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 E444420767 for ; Tue, 14 Apr 2020 18:16:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b="jMsnVOi0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E444420767 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=igalia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:36970 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jOQ6R-0003Uk-06 for qemu-devel@archiver.kernel.org; Tue, 14 Apr 2020 14:16:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57114) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jOQ4Z-00027Q-Dm for qemu-devel@nongnu.org; Tue, 14 Apr 2020 14:14:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jOQ4X-0007ST-Be for qemu-devel@nongnu.org; Tue, 14 Apr 2020 14:14:10 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:49535) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1jOQ4W-0007Ib-Nu; Tue, 14 Apr 2020 14:14:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Type:MIME-Version:Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From; bh=gDpXkzNzsvU345GogXYNDjW3mv0RXkGt8x/+wrkTnxg=; b=jMsnVOi0yHyjaAVKRoJD6N3v7YXfGbrmHCSN6alk7onMbXHa5/QNcBLgBTruXtmmd2xvyGlCtlLfLDdWiMNn7Bzc6cas73/spp5yzOO7cg3GCn8AkjdOeXecBiFqbC61vze/sJ2WQW8dRYPerlFRtj1twteesBdeDRuIISqz+03voDeYB3SOT7hOclErX39Or12iq1Ko0Z5ZQAOPv98R4pggArOTVDR/w2rrC4eMkJRQlMPDMpVkKGfSJf5gUMkvhgREyPRJDqb/A04gGR2NeRturr/9h6eTQ4Yywkfz1rY/+opJ2DscfKCgnwe4UzQnC5rkDsKdjrGhIUIqjyOj7g==; Received: from maestria.local.igalia.com ([192.168.10.14] helo=mail.igalia.com) by fanzine.igalia.com with esmtps (Cipher TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim) id 1jOQ4B-00075u-1V; Tue, 14 Apr 2020 20:13:47 +0200 Received: from berto by mail.igalia.com with local (Exim) id 1jOQ4A-0004pp-OK; Tue, 14 Apr 2020 20:13:46 +0200 From: Alberto Garcia To: Vladimir Sementsov-Ogievskiy , Eric Blake , qemu-devel@nongnu.org Subject: Re: [PATCH v4 07/30] qcow2: Document the Extended L2 Entries feature In-Reply-To: <094350fe-736a-d566-7dd7-716fd87eee81@virtuozzo.com> References: <8c88b96f-c6f5-e06c-73e1-56001089a7ca@redhat.com> <781c734c-e53c-76ae-74de-26d9e827e1a2@virtuozzo.com> <83922517-b5f5-2d4a-6518-c1912942ad27@virtuozzo.com> <094350fe-736a-d566-7dd7-716fd87eee81@virtuozzo.com> User-Agent: Notmuch/0.18.2 (http://notmuchmail.org) Emacs/24.4.1 (i586-pc-linux-gnu) Date: Tue, 14 Apr 2020 20:13:46 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x (no timestamps) [generic] [fuzzy] X-Received-From: 178.60.130.6 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 , "Denis V . Lunev" , Anton Nefedov , qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue 14 Apr 2020 08:06:38 PM CEST, Vladimir Sementsov-Ogievskiy wrote: >>> In other words, cluster can't be unallocated with data file in use. >> >> I still don't follow... clusters can be unallocated, and when you >> create a new image they are indeed unallocated. > > with external data file? Than we probably need to fix spec.. > > unallocated mean that offset is 0, and bit 63 is unset. But this can't > be when and exernal data file is used, accordingly to the spec. > > Or what am I missing? $ qemu-img create -f qcow2 -o data_file=data.raw img.qcow2 1M $ qemu-io -c 'write 0 192k' img.qcow2 $ qemu-io -c 'write -z -u 64k 64k' img.qcow2 Clusters #0 and #2 are allocated (offsets 0x00000 and 0x20000), cluster #1 is unallocated (offset 0, bit 63 unset, bit 0 -all zeroes- set). Berto