From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34152) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W5n1X-0005Q7-E7 for qemu-devel@nongnu.org; Tue, 21 Jan 2014 20:54:41 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W5n1R-0007KE-DI for qemu-devel@nongnu.org; Tue, 21 Jan 2014 20:54:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:24313) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W5n1R-0007JC-3n for qemu-devel@nongnu.org; Tue, 21 Jan 2014 20:54:29 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s0M1sRhM004445 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 21 Jan 2014 20:54:27 -0500 Date: Wed, 22 Jan 2014 09:54:26 +0800 From: Fam Zheng Message-ID: <20140122015426.GD24604@T430.redhat.com> References: <4cd22b3505eff19fd2492cd4e60120810714f97e.1390321064.git.jcody@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4cd22b3505eff19fd2492cd4e60120810714f97e.1390321064.git.jcody@redhat.com> Subject: Re: [Qemu-devel] [PATCH v2 2/3] 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 Tue, 01/21 11:31, 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 | 36 ++++++++++++++++++++++++++++++++++++ > 1 file changed, 36 insertions(+) > > diff --git a/block/mirror.c b/block/mirror.c > index 2932bab..528b61a 100644 > --- a/block/mirror.c > +++ b/block/mirror.c > @@ -630,11 +630,47 @@ void commit_active_start(BlockDriverState *bs, BlockDriverState *base, > BlockDriverCompletionFunc *cb, > void *opaque, Error **errp) > { > + int64_t length, base_length; > + int orig_base_flags; > + > + orig_base_flags = bdrv_get_flags(base); > + > if (bdrv_reopen(base, bs->open_flags, errp)) { > return; > } > + > + length = bdrv_getlength(bs); > + base_length = bdrv_getlength(base); > + > + if (length < 0 || base_length < 0) { I prefer to add an error to errp here, at least tell which bdrv_getlength failed helps. > + goto error_restore_flags; > + } > + > + if (length > base_length) { > + 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); > + goto error_restore_flags; > + } > + } else if (length < 0) { > + goto error_restore_flags; > + } > + > + > bdrv_ref(base); > mirror_start_job(bs, base, speed, 0, 0, > on_error, on_error, cb, opaque, errp, > &commit_active_job_driver, false, base); > + if (error_is_set(errp)) { > + goto error_restore_flags; > + } > + > + return; > + > +error_restore_flags: > + /* ignore error and errp for bdrv_reopen, because we want to propagate > + * the original error */ > + bdrv_reopen(base, orig_base_flags, NULL); Well, I hope this never fail. (But if it does, should we do anything else than ignoring it?) Thanks, Fam > + return; > } > -- > 1.8.3.1 >