From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54468) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W3JUr-0003rC-TM for qemu-devel@nongnu.org; Wed, 15 Jan 2014 00:58:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W3JUl-0000FR-V9 for qemu-devel@nongnu.org; Wed, 15 Jan 2014 00:58:37 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53402) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W3JUl-0000FA-N8 for qemu-devel@nongnu.org; Wed, 15 Jan 2014 00:58:31 -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 (8.14.4/8.14.4) with ESMTP id s0F5wToY025515 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 15 Jan 2014 00:58:30 -0500 Date: Wed, 15 Jan 2014 13:58:29 +0800 From: Fam Zheng Message-ID: <20140115055829.GA25475@T430.nay.redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCH 2/2] block: resize backing image during active layer commit, if needed List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jeff Cody Cc: kwolf@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com On Mon, 01/13 15:18, Jeff Cody wrote: > If the top image to commit is the active layer, and also larger than > the base image, then an I/O error will likely be returned during > block-commit. > > For instance, if we have a base image with a virtual size 10G, and a > active layer image of size 20G, then committing the snapshot via > 'block-commit' will likely fail. > > This will automatically attempt to resize the base image, if the > active layer image to be committed is larger. > > Signed-off-by: Jeff Cody > --- > block/mirror.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/block/mirror.c b/block/mirror.c > index 2932bab..c4e42fa 100644 > --- a/block/mirror.c > +++ b/block/mirror.c > @@ -630,9 +630,22 @@ void commit_active_start(BlockDriverState *bs, BlockDriverState *base, > BlockDriverCompletionFunc *cb, > void *opaque, Error **errp) > { > + int64_t length; > if (bdrv_reopen(base, bs->open_flags, errp)) { > return; > } "base" is already reopened here. > + > + length = bdrv_getlength(bs); > + > + if (length > bdrv_getlength(base)) { > + if (bdrv_truncate(base, length) < 0) { > + error_setg(errp, "Top image %s is larger than base image %s, and " > + "resize of base image failed.", > + bs->filename, base->filename); > + return; Should we restore open flags for base? Thanks, Fam > + } > + } > + > bdrv_ref(base); > mirror_start_job(bs, base, speed, 0, 0, > on_error, on_error, cb, opaque, errp, > -- > 1.8.3.1 >