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 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 7A570C2BA19 for ; Wed, 15 Apr 2020 19:12:01 +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 3343220768 for ; Wed, 15 Apr 2020 19:12:01 +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="huJS5gNJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3343220768 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]:54220 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jOnS4-0000xT-8c for qemu-devel@archiver.kernel.org; Wed, 15 Apr 2020 15:12:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56250) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jOnRO-0000Tm-Rx for qemu-devel@nongnu.org; Wed, 15 Apr 2020 15:11:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jOnRN-0008HT-SW for qemu-devel@nongnu.org; Wed, 15 Apr 2020 15:11:18 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:40983) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1jOnRN-0008Fh-9N; Wed, 15 Apr 2020 15:11:17 -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=NBEiVHvrfQXWjeN56IEMW0el7B5LI/AnEx3OzhyA2Rs=; b=huJS5gNJjvC5Uf0WwtKvsl0XzfIXOxtxHxaiJRKjroyJJ+WQpgHoQdcmCFimG+dQpCBaJH1CjlB2H7vnq8waHnx3os9RnOL/jPL/Pj3Pp6gBYC2ufZcI2qbnFaGCtc1T4XDIXPI9bbKOs7xk36IG+aDq+JX4W62TPvvH+Mk4zmoztZE9tEjEC2/OxdvmYS0JHId1I0U2UI0qaue0E4P93ryW9m2h46GnsRrmc+QHsJ9LfISBIvmyAVguzaCek8LTEqqYrsSj6yyjN1tGyV1VyE0iTUBs9kTGbzMt4837K1BGmUYowqSPUZ5GO1uFKt3bf9uF8nQy1XsFcWSpvrXI1Q==; 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 1jOnRI-0006Rj-BW; Wed, 15 Apr 2020 21:11:12 +0200 Received: from berto by mail.igalia.com with local (Exim) id 1jOnRI-000810-28; Wed, 15 Apr 2020 21:11:12 +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: <781c734c-e53c-76ae-74de-26d9e827e1a2@virtuozzo.com> References: <8c88b96f-c6f5-e06c-73e1-56001089a7ca@redhat.com> <781c734c-e53c-76ae-74de-26d9e827e1a2@virtuozzo.com> User-Agent: Notmuch/0.18.2 (http://notmuchmail.org) Emacs/24.4.1 (i586-pc-linux-gnu) Date: Wed, 15 Apr 2020 21:11:12 +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 Fri 10 Apr 2020 11:29:59 AM CEST, Vladimir Sementsov-Ogievskiy wrote: >> Should we also document that extended L2 entries are incompatible >> with raw external files? [...] After all, when raw external file is >> enabled, the entire image is allocated, at which point subclusters >> don't make much sense. > > It still may cache information about zeroed subclusters: gives more > detailed block-status. So shall I forbid extended_l2 + data_file_raw then? I wonder, if the only problem is that it's just not very useful, does it make sense to add additional complexity and restrictions to the code simply to prevent the user from making a sub-optimal choice? Berto