Date: Sun, 23 Aug 2009 16:33:03 +0200 From: Ulrich =?utf-8?B?U3DDtnJsZWlu?= <uqs@spoerlein.net> To: Pawel Jakub Dawidek <pjd@freebsd.org> Cc: current@freebsd.org Subject: Re: Cannot mount / from UFS labels Message-ID: <20090823143303.GN91417@acme.spoerlein.net> In-Reply-To: <20090822002822.GA2613@garage.freebsd.pl> References: <20090821131723.GA91417@acme.spoerlein.net> <20090822002822.GA2613@garage.freebsd.pl>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sat, 22.08.2009 at 02:28:22 +0200, Pawel Jakub Dawidek wrote: > On Fri, Aug 21, 2009 at 03:17:23PM +0200, Ulrich Spörlein wrote: > > I'm not sure this ever worked for 7.x but now I need to have the same > > root fs device on two machines: labels to the rescue! As I don't want to > > use the GEOM labels, but UFS labels, this is what I did: > > > > # tunefs -L root / (in single user) > > then updated /etc/fstab and rebooted > > The problem is this: tunefs will write volume name into file system's > superblock on the disk. Then you remount read-write and UFS will overwrite > superblock with in-memory copy it picked up on first read-only mount (no volume > name in there). So there will be no volume name in the superblock anymore. You > can confirm that with: > > # tunefs -L root /dev/ad0s1a > # dumpfs /dev/ad0s1a | grep volname > There should be volume name here. > # mount -uw / > # dumpfs /dev/ad0s1a | grep volname > No volume name here. > > You cannot remount it read-only again and use tunefs again, because this is a > bit of a hack how it works now. Only first read-only mount opens GEOM provider > (eg. /dev/ad0s1a) for reading, but without exclusive bit. Once you remount it > the exclusive bit will be there and you will no longer be able to use tunefs on > this file system. You can confirm that with: > > # gpart list | grep -A3 'Name: ad0s1a' > Take a look at the 'e' (exclusive) count. > > So what you have to do instead is to boot into single-user mode, put volume > name using tunefs and reboot without remounting the file system. I had a hunch that this might work, thanks for confirming, I now also used this for my other machines and can confirm it worked. Cheers, Uli
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20090823143303.GN91417>