Yellow Bug Computers - TechDocs - Mandrake Locked External Drives

Unlocking a Floppy or other Input Device
in Mandrake-Linux

Disclaimer: Make modifications to your system at your own risk. I like to hack on my server all day, but it isn't a production machine so I don't worry if it crashes. Make backups of everything important, and never try things first on a production machine!

The Problem | Why it Occurs | How to Fix | Supermount | Another Fix

/mnt/floppy locked! I can't access the floppy drive!

This is a common occurrence in Mandrake Linux 9.0. Typically the question arises in a couple of different ways:

"All of a sudden I can't access my floppy, cdrom, or zip drive. All of these directories are locked! I wasn't doing anything. They worked yesterday, but not today. What happened?"

Why it Occurs:

The directory that the mount point is pointing to is locked. This can occur when another user has mounted a drive and another user tries to access that drive or unmount it. Typically only the user who has mounted the drive can unmount it. In this instance however, even the root user cannot access the locked mount point.

When root cannot access the locked drives, two things may solve the issue. First, the Supermount function needs to be disabled. If that doesn't resolve the problem, the links to the mount points need to be re-created. These two solutions will fix the problem 9 times out of 10.

How to I Fix it? [top]
First check out this common solution:

Unmount the Drives:
Check to see if you actually have unmounted the last device that was mounted. For example, if you took the floppy or cdrom out of the device, and did not unmount it, that could cause a problem. To properly unmount the device, either as root or as the user who first mounted the device:

umount /mnt/floppy

Here is another fix:

Disable Supermount: [top]
There is a known problem with the Supermount utility bundled with Mandrake 9.0. At the command line please read the short man page for supermount:

man supermount

Next, disable supermount by being logged in as root, and typing:

supermount -i disable

If you currently have any disk icons on the desktop those will become unusable. You can delete them, and then create shortcuts of your own, pointing to the appropriate mount directories. Then, right click on the shortcut, selecting mount or unmount when appropriate.

Now you'll have to mount and unmount disks manually, but at least you can use them again. :-)

If this doesn't fix the problem, continue on by next looking at the relevant files:

Common Files to look at first:

What you can't access is the directory that the contents of a drive are supposed to be mounted into. Basically, you can mount a directory any old place you want to. The standard mount points that Mandrake and most Linux distributions use are located in the /mnt directory and are:

drwxrwxrwx	1 root	root	0 Jan 25 01:42 cdrom/
drwxrwxrwx	1 root	root	0 Jan 25 01:42 cdrom2/
drwxr-xr-x	2 root	root	4096 Dec 22 21:59 disk/
drwxrwxrwx	1 root	root	0 Jan 25 01:42 floppy/

There are a few other files to know about that might help you in your journey:

The fstab file shows the linkings between mount points and actual partitions or drives

The mtab is supposed to show what is currently mounted. It is a dynamic file.

I'm not sure if they are called "device drivers" but that is how I like to think of them. In the /dev directory are hundreds of device drivers for everything you can imagine.

Examples of the Fstab:

The fstab says, for this partition, use this device driver:

none /mnt/cdrom2 supermount dev=/dev/scd0

scd0 is actually located in the /dev directory.

none /mnt/cdrom supermount dev=/dev/hdc

hdc is also in the /dev directory.

Taking a Peek Inside the /dev Directory:

Make sure you have changed into the /dev directory:

cd /dev

To see the listing page by page of devices in dev type:

ls -la | more

You will see that the different devices have ----> after them

That means that that device points to a different directory, a soft link.

So for example, fdo (which is the primary floppy device) points to floppy

If you look at the two dev lines for your two cdrom drives, sdo and hdc you'll see the two links they point to.

These links need to be deleted and recreated.

Just try one at a time, logged in as root.

I actually had to reboot my computer for the changes to take, although if I was a good geek I'd just know which service to restart. Normally you shouldn't have to reboot.

Re-creating the damaged/locked link:

You want to be in the /dev directory, so type cd /dev as the root user.