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Can't mount CD: "unknown filesystem type 'iso9660'"

I just upgraded to Ubuntu 9.10 Server (the VM distribution), and now I can't mount my VM's CD drive.

Code:

$ sudo mount /dev/cdrom /media/cdrom

mount: unknown filesystem type 'iso9660'

iso9660 is not listed as a filesystem in /proc/filesystems -- I dunno if it ever was.

I'm not sure how to get this to work again, and my Googling has been remarkably unhelpful.

Anyone know what I need to do? Any tips would be greatly appreciated.

If I get this correctly, you're trying to mount the CD in your virtual machine. If this is right then check by ejecting/unmounting the CD from the host machine. This happens a lot in Parallels where in after ejecting the CD from the host operating system, it would be accessible for the guest operating system(VM).

I'm actually just trying to mount an ISO which I've mounted through VirtualBox. I've of course tried "virtually-ejecting" it in VirtualBox; that didn't help.

Does your VM's kernel have an iso9660 kernel module you can modprobe?
If you don't have this filesytem in the kernel, you won't be able to mount it, even if you have access to the device in your VM.

Code:

$ sudo modprobe iso9660

FATAL: Module iso9660 not found.

I'll take that as a no?

I guess I'll go file a bug with Ubuntu. I'm pretty surprised that they took this out of their VM kernel, if that's what's indeed going on.

I'm not home right now and can't double check the name. Check if you can modprobe isofs. It might be an alias set in /etc/modprobe.conf or a file in /etc/modprobe.d/. Sometimes a kernel module may change names between kernel versions as well. For example, tcp_conntrack was renamed nf_conntrack in recent kernels. Also check the /boot/config-<version> file for what kernel options were used. Some kernels have a /proc/config.gz file (if this feature is enabled) you can use as well.

Can't modprobe isofs.

There's this in my /boot/config-2.6.31-14-generic-pae:

Code:

#

# CD-ROM/DVD Filesystems

#

CONFIG_ISO9660_FS=m

CONFIG_JOLIET=y

CONFIG_ZISOFS=y

CONFIG_UDF_FS=m

CONFIG_UDF_NLS=y

I have a similar "CONFIG_ISO9660_FS=y" config entry for my kernel, but it is built-in so I don't see an iso9660 kernel module. However, I don't have an iso9660.ko entry in modules.builtin. Looking for iso9660.ko might be a fools errand.

Double check your config settings for your running kernel:
zcat /proc/config.gz | grep ISO9660
zcat /proc/config.gz | grep ISOFS

Look at your boot up messages for your VM. Is the cdrom/dvd device itself detected?

Quote:

Originally Posted by jschiwal (Post 3746604)

I have a similar "CONFIG_ISO9660_FS=y" config entry for my kernel

Mine is CONFIG_ISO9660_FS=m, not 'y'. Perhaps 'm' stands for 'manual'?

Quote:

Double check your config settings for your running kernel:
zcat /proc/config.gz | grep ISO9660
zcat /proc/config.gz | grep ISOFS

I don't have a /proc/config.gz Maybe this file is somewhere else?

Quote:

Look at your boot up messages for your VM. Is the cdrom/dvd device itself detected?

From dmesg | grep -i cd:

Code:

[    0.973415] ata2.00: ATAPI: VBOX CD-ROM, 1.0, max UDMA/133

[    0.975142] scsi 1:0:0:0: CD-ROM            VBOX    CD-ROM          1.0  PQ: 0 ANSI: 5

[    0.976872] Uniform CD-ROM driver Revision: 3.20

[    0.976986] sr 1:0:0:0: Attached scsi CD-ROM sr0

On this SuSE system the module isofs.ko needed to be loaded into the kernel, but is was dependent on nls_base.ko that had to be loaded first. So the short answer is:

Code:

# insmod /lib/modules/3.0.101-0.46-ec2/kernel/fs/nls/nls_base.ko

# insmod /lib/modules/3.0.101-0.46-ec2/kernel/fs/isofs/isofs.ko

I figured it out in the following way which might be useful for similar problems:

Code:

# mount -o loop SLES-11-SP2-DVD-i586-GM-DVD1.iso sles11sp3-32

mount: unknown filesystem type 'iso9660'

so filesystem is unknown

Code:

# modprobe iso9660

FATAL: Could not load /lib/modules/3.0.82-0.7-ec2/modules.dep: No such file or directory

whoah

Code:

# cat /boot/config-3.0.101-0.46-ec2 |grep 9660

CONFIG_ISO9660_FS=m

apparently, it's not in the kernel, but it is some loadable kernel module (m) that can be loaded on request

Code:

# find / -name isofs.ko

/lib/modules/3.0.101-0.46-ec2/kernel/fs/isofs/isofs.ko

so there it is

Code:

# insmod /lib/modules/3.0.101-0.46-ec2/kernel/fs/isofs/isofs.ko

insmod: error inserting '/lib/modules/3.0.101-0.46-ec2/kernel/fs/isofs/isofs.ko': -1 Unknown symbol in module

but I cannot insert it in the kernel. It turns out it's dependent on some other kernel module
the way to find out is depmod, apparently

Code:

# depmod /lib/modules/3.0.101-0.46-ec2/kernel/fs/isofs/isofs.ko

FATAL: Could not open /lib/modules/3.0.82-0.7-ec2/modules.dep.temp for writing: No such file or directory

mmm. well we can solve that, no?

Code:

# mkdir /lib/modules/3.0.82-0.7-ec2

# depmod /lib/modules/3.0.101-0.46-ec2/kernel/fs/*/*.ko

# grep isofs /lib/modules/3.0.82-0.7-ec2/modules.dep

/lib/modules/3.0.101-0.46-ec2/kernel/fs/isofs/isofs.ko: /lib/modules/3.0.101-0.46-ec2/kernel/fs/nls/nls_base.ko

so there's the dependency

Code:

# insmod /lib/modules/3.0.101-0.46-ec2/kernel/fs/nls/nls_base.ko

# insmod /lib/modules/3.0.101-0.46-ec2/kernel/fs/isofs/isofs.ko

looks promising...

Code:

# mount SLES-11-SP2-DVD-i586-GM-DVD1.iso sles11sp3-32 -o loop

mount: block device [...]/SLES-11-SP2-DVD-i586-GM-DVD1.iso is write-protected, mounting read-only

and jackpot!