From patchwork Mon Jan 24 21:10:42 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 80273 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id C25A7B711F for ; Tue, 25 Jan 2011 08:46:49 +1100 (EST) Received: from localhost ([127.0.0.1]:44515 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PhUFK-0000Vx-8u for incoming@patchwork.ozlabs.org; Mon, 24 Jan 2011 16:46:46 -0500 Received: from [140.186.70.92] (port=60772 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PhTfn-00017P-RA for qemu-devel@nongnu.org; Mon, 24 Jan 2011 16:10:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PhTfl-0007TR-Ho for qemu-devel@nongnu.org; Mon, 24 Jan 2011 16:10:03 -0500 Received: from mx1.redhat.com ([209.132.183.28]:19762) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PhTfl-0007SO-7O for qemu-devel@nongnu.org; Mon, 24 Jan 2011 16:10:01 -0500 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id p0OL9wBw031531 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 24 Jan 2011 16:09:58 -0500 Received: from dhcp-5-188.str.redhat.com (vpn1-5-230.ams2.redhat.com [10.36.5.230]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p0OL9I7A003712; Mon, 24 Jan 2011 16:09:57 -0500 From: Kevin Wolf To: anthony@codemonkey.ws Date: Mon, 24 Jan 2011 22:10:42 +0100 Message-Id: <1295903452-18017-14-git-send-email-kwolf@redhat.com> In-Reply-To: <1295903452-18017-1-git-send-email-kwolf@redhat.com> References: <1295903452-18017-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. Cc: kwolf@redhat.com, qemu-devel@nongnu.org Subject: [Qemu-devel] [PATCH 13/23] Documentation: Add qemu-img check/rebase X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Signed-off-by: Kevin Wolf --- qemu-img.texi | 41 +++++++++++++++++++++++++++++++++++++++++ 1 files changed, 41 insertions(+), 0 deletions(-) diff --git a/qemu-img.texi b/qemu-img.texi index 1b90ddb..ced64a4 100644 --- a/qemu-img.texi +++ b/qemu-img.texi @@ -59,6 +59,13 @@ lists all snapshots in the given image Command description: @table @option +@item check [-f @var{fmt}] @var{filename} + +Perform a consistency check on the disk image @var{filename}. + +Only the formats @code{qcow2}, @code{qed} and @code{vdi} support +consistency checks. + @item create [-f @var{fmt}] [-o @var{options}] @var{filename} [@var{size}] Create the new disk image @var{filename} of size @var{size} and format @@ -107,6 +114,40 @@ they are displayed too. List, apply, create or delete snapshots in image @var{filename}. +@item rebase [-f @var{fmt}] [-u] -b @var{backing_file} [-F @var{backing_fmt}] @var{filename} + +Changes the backing file of an image. Only the formats @code{qcow2} and +@code{qed} support changing the backing file. + +The backing file is changed to @var{backing_file} and (if the image format of +@var{filename} supports this) the backing file format is changed to +@var{backing_fmt}. + +There are two different modes in which @code{rebase} can operate: +@table @option +@item Safe mode +This is the default mode and performs a real rebase operation. The new backing +file may differ from the old one and qemu-img rebase will take care of keeping +the guest-visible content of @var{filename} unchanged. + +In order to achieve this, any clusters that differ between @var{backing_file} +and the old backing file of @var{filename} are merged into @var{filename} +before actually changing the backing file. + +Note that the safe mode is an expensive operation, comparable to converting +an image. It only works if the old backing file still exists. + +@item Unsafe mode +qemu-img uses the unsafe mode if @code{-u} is specified. In this mode, only the +backing file name and format of @var{filename} is changed without any checks +on the file contents. The user must take care of specifying the correct new +backing file, or the guest-visible content of the image will be corrupted. + +This mode is useful for renaming or moving the backing file to somewhere else. +It can be used without an accessible old backing file, i.e. you can use it to +fix an image whose backing file has already been moved/renamed. +@end table + @item resize @var{filename} [+ | -]@var{size} Change the disk image as if it had been created with @var{size}.