From patchwork Fri Apr 10 12:18:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alberto Garcia X-Patchwork-Id: 11483243 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B591517D4 for ; Fri, 10 Apr 2020 12:19:12 +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 38E0E20753 for ; Fri, 10 Apr 2020 12:19:12 +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="Ls5xg5k1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 38E0E20753 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:33608 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jMscp-0005wW-4g for patchwork-qemu-devel@patchwork.kernel.org; Fri, 10 Apr 2020 08:19:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36457) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jMscG-0005NJ-T4 for qemu-devel@nongnu.org; Fri, 10 Apr 2020 08:18:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jMscF-0007Bv-UO for qemu-devel@nongnu.org; Fri, 10 Apr 2020 08:18:36 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:36335) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1jMscF-0007BT-DI; Fri, 10 Apr 2020 08:18:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:Message-Id:Date:Subject:Cc:To:From; bh=Hz3ulBmdpF4r2v6cud9D5vQ2ufWiyxbShw1ne3elaLE=; b=Ls5xg5k1TmKAulGGhiYfDOBbINRPE1HlyPxZmsNCcR2MefWPWnG6bbdWx+h+qFGYOepoWVA5C+uBcJBBEe/jSjefRBZehVRJjZk7rMQnrktvDbYBAhwEyV0K0RFySKztHUHmAGSCCUFaM07D5pVWtmuSEzYjMbTuliurAak87CAMXiJiLYxBch0lONedUXMVv1EjwbOHlPgHlw1r363ou/fPub+UtFluUKADydbXQvnu4v9Pmv8LXfuOW047n/CggeQNDSg3eovBNQ8xPQY6NoodrS1qLLMOx4scuVrQW0uUQTJiPJ4dE2Dp2ODdtbndCQCOIX3YhyPrKS7oGhTjfg==; Received: from static.113.35.0.81.ibercom.com ([81.0.35.113] helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1jMscD-0000On-6G; Fri, 10 Apr 2020 14:18:33 +0200 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1jMsby-0002BA-D2; Fri, 10 Apr 2020 14:18:18 +0200 From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [PATCH for-5.0] qcow2: Add incompatibility note between backing files and raw external data files Date: Fri, 10 Apr 2020 14:18:15 +0200 Message-Id: <20200410121816.8334-1-berto@igalia.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 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 , Alberto Garcia , qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" Backing files and raw external data files are mutually exclusive. The documentation of the raw external data bit (in autoclear_features) already indicates that, but we should also mention it on the other side. Suggested-by: Eric Blake Signed-off-by: Alberto Garcia Reviewed-by: Eric Blake --- docs/interop/qcow2.txt | 3 +++ 1 file changed, 3 insertions(+) diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt index 640e0eca40..298a031310 100644 --- a/docs/interop/qcow2.txt +++ b/docs/interop/qcow2.txt @@ -25,6 +25,9 @@ The first cluster of a qcow2 image contains the file header: is stored (NB: The string is not null terminated). 0 if the image doesn't have a backing file. + Note: backing files are incompatible with raw external data + files (auto-clear feature bit 1). + 16 - 19: backing_file_size Length of the backing file name in bytes. Must not be longer than 1023 bytes. Undefined if the image doesn't have