[TriLUG] Problems with /etc/mtab

[Steven Blanchard]

Janyne Kizer wrote:
> I was wondering what would cause /etc/mtab to report that one device
> (floppy) is mounted twice?  This has happened on one of our systems and
> I was just wondering what on earth caused this.  Could this be caused by
> trying to mount and bad floppy?
> 
> Thsi is part of the file in question
> 
> /dev/fd0 /floppy vfat rw,noexec,nosuid,nodev,user=userid1 0 0
> /dev/fd0 /floppy vfat rw,noexec,nosuid,nodev,user=userid2 0 0
> 
> /proc/mounts lists the device once:
> 
> /dev/fd0 /mnt/floppy vfat rw,nosuid,nodev,noexec 0 0
> 
> One of the people who uses that system has reported the following error
> message:
> 
> umount: it seems /floppy is mounted multiple times
> 
> Any ideas?  Inquiring minds want to know :-)
> 

It looks like /etc/fstab mount the floppy with the user option. I bet 
user1 mounted a floppy, and removed it without unmounting it. user2 
mounted his/her floppy, but cant unmount it because only the user who 
mounted the floppy can unmount it. Since mount can not tell who that 
was, it wont allow either user to unmount the floppy. The floppy can 
probabally be unmounted as root.

My understanding is that instead of using the user option is /etc/fstab, 
you could use the owner option (which redhat uses). When the owner 
option is used, /etc/security/console.perms must set the owner of 
/dev/fd0 to whomever is logged in on the console. That may solve the 
problem.