CentOS 6.4: Unable to mount disc, doesn't like UDF

Question

I'm trying to use a CD on CentOS 6.4, but I keep getting this error:

Unable to mount Disc Error mounting: mount: unknown filesystem type 'udf'

I've installed udftools

I've tried changing the permissions around on /dev/sr0 to no avail.

I've tried various ways of mounting the disc such as:

• mount /dev/sr0 /mnt (unknown filesystem type 'udf')
• mount -t auto /dev/sr0 /mnt (unknown filesystem type 'udf')
• mount -r -t iso9660 /dev/sr0 /mnt (wrong fs type...)
• mount -t udf /dev/sr0 /mnt (unknown filesystem type 'udf', despite being in the man page for mount)
• dd if=/dev/sr0 of=disc.iso -> mount -o loop disc.iso /mnt -t iso9660

I can see and read from the disc just fine in a VM on that host and on other physical machines.

It also seems to happen with just about every disc that I've tried.

Any thoughts?

Answer 1

I've figured out the issue. Someone had added a line in this file:

/etc/modprobe.d/disabled.conf

that said:

install udf /bin/false

I simply commented it out, and I'm now able to mount discs.

Answer 2

I had the same issue, but it got disabled by a CIS security baseline setting located at the following location:

/etc/modprobe.d/cis_disable_fs.conf

Commented the install udf /bin/true line and it worked.

Answer 3

I got the same error message. Checked /etc/modprobe.d and found a file called usgcb.blacklist. In there it had.....

install udf /bin/true 

Commented it out and now our system can read a CD-ROM

Answer 4

You don't say this but I get the impression you're attempting to mount the DVD drive using just your regular userid, which typically is not allowed to make use of the mount command as you're attempting to do so.

To mount using mount you typically need to be root or have sudo privileges to do this:

$ sudo mount -t udf /dev/sr0 /mnt

This command should typically "just work" on most Linuxes. Occasionally you might need to do it like so:

$ sudo mount -t udf /dev/dvd /mnt

Drive capabilities

If you're not having any luck you can check your drives capabilities using the command line tool wodim.

$ wodim -prcap
wodim: Operation not permitted. Warning: Cannot raise RLIMIT_MEMLOCK limits.
Device was not specified. Trying to find an appropriate drive...
Detected CD-R drive: /dev/sr0
Using /dev/cdrom of unknown capabilities
Device type    : Removable CD-ROM
Version        : 5
Response Format: 2
Capabilities   : 
Vendor_info    : 'Optiarc '
Identification : 'DVD RW AD-7930H '
Revision       : '1.D1'
Device seems to be: Generic mmc2 DVD-R/DVD-RW.

Drive capabilities, per MMC-3 page 2A:

  Does read CD-R media
  Does write CD-R media
  Does read CD-RW media
  Does write CD-RW media
  Does read DVD-ROM media
  Does read DVD-R media
  Does write DVD-R media
  Does read DVD-RAM media
  Does write DVD-RAM media
  Does support test writing

References

• Getting capabilities of my CD/DVD drive when wodim --devices doesn't work