From patchwork Thu Oct 26 07:59:47 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 10027715 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 26242601E8 for ; Thu, 26 Oct 2017 08:04:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 10EA426E38 for ; Thu, 26 Oct 2017 08:04:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 031B42811A; Thu, 26 Oct 2017 08:04:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6FD4026E38 for ; Thu, 26 Oct 2017 08:04:21 +0000 (UTC) Received: from localhost ([::1]:51536 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e7d9I-0004Uy-OK for patchwork-qemu-devel@patchwork.kernel.org; Thu, 26 Oct 2017 04:04:20 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49345) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e7d52-00020Z-Mj for qemu-devel@nongnu.org; Thu, 26 Oct 2017 03:59:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e7d51-0004g8-RB for qemu-devel@nongnu.org; Thu, 26 Oct 2017 03:59:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41732) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e7d4w-0004cl-Jd; Thu, 26 Oct 2017 03:59:50 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7D4FD7D0F1; Thu, 26 Oct 2017 07:59:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 7D4FD7D0F1 Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=mreitz@redhat.com Received: from localhost (ovpn-204-120.brq.redhat.com [10.40.204.120]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 126AA5C542; Thu, 26 Oct 2017 07:59:48 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Thu, 26 Oct 2017 09:59:47 +0200 Message-Id: <20171026075947.9597-1-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 26 Oct 2017 07:59:49 +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] [PATCH] 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: Kevin Wolf , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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 --- 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}