From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53236) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e7dGS-0007Yx-2R for qemu-devel@nongnu.org; Thu, 26 Oct 2017 04:11:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e7dGQ-0004Kp-R3 for qemu-devel@nongnu.org; Thu, 26 Oct 2017 04:11:44 -0400 Date: Thu, 26 Oct 2017 04:11:34 -0400 From: Jeff Cody Message-ID: <20171026081134.GA28110@localhost.localdomain> References: <20171026075947.9597-1-mreitz@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171026075947.9597-1-mreitz@redhat.com> Subject: Re: [Qemu-devel] [Qemu-block] [PATCH] qemu-img.1: Image invalidation on qemu-img commit List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Max Reitz Cc: qemu-block@nongnu.org, Kevin Wolf , qemu-devel@nongnu.org On Thu, Oct 26, 2017 at 09:59:47AM +0200, Max Reitz wrote: > 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 > --- > 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} > > -- > 2.13.6 > > Reviewed-by: Jeff Cody