Odd behavior of labels on different filesystem types

[Kevin Oberman]

> Sender: "J. Hellenthal" <jhellenthal at gmail.com>
> Date: Sun, 04 Jul 2010 01:55:20 -0400
> From: jhell <jhell at dataix.net>
> 
> On 07/03/2010 16:51, Kevin Oberman wrote:
> > I have run into an odd behavior in 8-stable that I can't see a reason
> > for.
> > 
> > If I have a FAT32 formatted removable drive, I get /dev entries for it
> > as both /dev/msdosfs/LABEL and /dev/ufsid/ID. When I mount the
> > filesystem, the /dev/ufsid label is removed, but the other two remain.
> > 
> > If I have a UFS filesystem on the disk, I have similar devices except
> > that the LABEL is /dev/ufs/LABEL. But, when the UFS device is mounted,
> > the /dev/ufsid/ID AND the /dev/ufs/LABEL devs are both deleted. 
> > 
> > I'm not sure which is "right", but I can't see the reason for the
> > different behavior and it has caused a fair bit of trouble when working
> > with gnome-mount as I can't unmount a ufs device. When the
> > /dev/ufs/LABEL device is created again on the umount, gnome-mount sees a
> > new device and immediately re-mounts it.
> > 
> > Can this inconsistency be corrected?
> 
> Can you try to zero out that disk first i.e.
> dd if=/dev/zero of=/dev/DISK bs=4m
> 
> Then format your msdos fat part and relabel it. You should not see a
> dev/ufsid/ label for this anymore. I believe that for some reason the
> ufsid metadata or whatever you want to call it some how has been left
> behind and is still being read for whatever reason and can be confirmed
> by this.
> 
> As for /dev/ufs/LABEL /dev/ufsid/ID /dev/device when you mount one the
> others should disapear so this is correct behavior.

Thanks for the suggestion. I will try a device which has never had a UFS
file system and see if the ufsid device is created. Looks like the
former is an issue with geom tasting and it would be nice to get it
fixed, but it is not what is causing my problem. It is the latter issue
that causes the problems with gnome-mount.

The real issue for me is that /dev/ufs/LABEL is removed on a mount while
/dev/msdosfs/LABEL remains. hald easily works around ufsid by ignoring
it, but the /dev/FS/LABEL has to be acted upon differently depending on
which filesystem is involved.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751