From patchwork Thu Oct 26 13:17:33 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 830683 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3yN7Xd47jmz9t6D for ; Fri, 27 Oct 2017 00:44:32 +1100 (AEDT) Received: from localhost ([::1]:52996 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e7iSU-00052E-KN for incoming@patchwork.ozlabs.org; Thu, 26 Oct 2017 09:44:30 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59154) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e7i3k-0000wZ-MN for qemu-devel@nongnu.org; Thu, 26 Oct 2017 09:19:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e7i3i-0002QO-33 for qemu-devel@nongnu.org; Thu, 26 Oct 2017 09:18:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33366) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e7i3f-0002NT-FX; Thu, 26 Oct 2017 09:18:51 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 963FF7CB92; Thu, 26 Oct 2017 13:18:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 963FF7CB92 Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=kwolf@redhat.com Received: from localhost.localdomain.com (unknown [10.36.118.24]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5DB087F5FF; Thu, 26 Oct 2017 13:18:49 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Date: Thu, 26 Oct 2017 15:17:33 +0200 Message-Id: <20171026131741.5059-28-kwolf@redhat.com> In-Reply-To: <20171026131741.5059-1-kwolf@redhat.com> References: <20171026131741.5059-1-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Thu, 26 Oct 2017 13:18:50 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 27/35] qemu-img.1: Image invalidation on qemu-img commit X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Max Reitz qemu-img commit invalidates all images between base and top. This should be mentioned in the man page. Suggested-by: Ping Li Signed-off-by: Max Reitz Reviewed-by: Jeff Cody Signed-off-by: Kevin Wolf --- qemu-img.texi | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/qemu-img.texi b/qemu-img.texi index ee5c5940d3..fdcf120f36 100644 --- a/qemu-img.texi +++ b/qemu-img.texi @@ -274,11 +274,10 @@ If the backing chain of the given image file @var{filename} has more than one layer, the backing file into which the changes will be committed may be specified as @var{base} (which has to be part of @var{filename}'s backing chain). If @var{base} is not specified, the immediate backing file of the top -image (which is @var{filename}) will be used. For reasons of consistency, -explicitly specifying @var{base} will always imply @code{-d} (since emptying an -image after committing to an indirect backing file would lead to different data -being read from the image due to content in the intermediate backing chain -overruling the commit target). +image (which is @var{filename}) will be used. Note that after a commit operation +all images between @var{base} and the top image will be invalid and may return +garbage data when read. For this reason, @code{-b} implies @code{-d} (so that +the top image stays valid). @item compare [-f @var{fmt}] [-F @var{fmt}] [-T @var{src_cache}] [-p] [-s] [-q] @var{filename1} @var{filename2}