From owner-freebsd-fs@FreeBSD.ORG  Tue Apr 21 17:01:43 2009
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
Delivered-To: freebsd-fs@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 7E8F7106567A;
	Tue, 21 Apr 2009 17:01:43 +0000 (UTC) (envelope-from avg@freebsd.org)
Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140])
	by mx1.freebsd.org (Postfix) with ESMTP id 7F29F8FC25;
	Tue, 21 Apr 2009 17:01:42 +0000 (UTC) (envelope-from avg@freebsd.org)
Received: from odyssey.starpoint.kiev.ua (alpha-e.starpoint.kiev.ua
	[212.40.38.101])
	by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id TAA19084;
	Tue, 21 Apr 2009 19:51:34 +0300 (EEST)
	(envelope-from avg@freebsd.org)
Message-ID: <49EDF995.2050508@freebsd.org>
Date: Tue, 21 Apr 2009 19:51:33 +0300
From: Andriy Gapon <avg@freebsd.org>
User-Agent: Thunderbird 2.0.0.21 (X11/20090406)
MIME-Version: 1.0
To: Ivan Voras <ivoras@freebsd.org>
References: <49EDCA21.70908@icyb.net.ua> <gskrld$vo0$1@ger.gmane.org>
	<49EDF80F.3070105@icyb.net.ua>
In-Reply-To: <49EDF80F.3070105@icyb.net.ua>
X-Enigmail-Version: 0.95.7
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Cc: freebsd-fs@freebsd.org, freebsd-geom@freebsd.org
Subject: Re: glabel for ufs: size check is overzealous?
X-BeenThere: freebsd-fs@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Filesystems <freebsd-fs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-fs>
List-Post: <mailto:freebsd-fs@freebsd.org>
List-Help: <mailto:freebsd-fs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 21 Apr 2009 17:01:43 -0000

on 21/04/2009 19:45 Andriy Gapon said the following:
> Maybe this is a check against disk space being re-used for some other fs and
> super-block staying sufficiently intact. But, OTOH, fs_fsize and fs_size could
> still match the raw media in this case too.
> If some extra sanity checks are needed in addition to magic then
> fs_bmask/fs_fmask/fs_bshift/fs_fshift and/or any other derived fields could be used.
> 

BTW, right now I put this in my local tree:

diff --git a/sys/geom/label/g_label_ufs.c b/sys/geom/label/g_label_ufs.c
index 8510fc0..0cffb8d 100644
--- a/sys/geom/label/g_label_ufs.c
+++ b/sys/geom/label/g_label_ufs.c
@@ -83,10 +83,10 @@ g_label_ufs_taste_common(struct g_consumer *cp, char *label,
size_t size, int wh
 			continue;
 		/* Check for magic and make sure things are the right size */
 		if (fs->fs_magic == FS_UFS1_MAGIC && fs->fs_fsize > 0 &&
-		    pp->mediasize / fs->fs_fsize == fs->fs_old_size) {
+		    pp->mediasize / fs->fs_fsize >= fs->fs_old_size) {
 		    	/* Valid UFS1. */
 		} else if (fs->fs_magic == FS_UFS2_MAGIC && fs->fs_fsize > 0 &&
-		    pp->mediasize / fs->fs_fsize == fs->fs_size) {
+		    pp->mediasize / fs->fs_fsize >= fs->fs_size) {
 		    	/* Valid UFS2. */
 		} else {
 			g_free(fs);

-- 
Andriy Gapon