Cannot Mount CD-ROM [Solved]

[Kenji Miyamoto]

I have tried several different data CDs, but am unable to get them to mount. Oddly, music CDs work perfectly. I can also mount any other form of storage.

First off, I have compiled in support for every CD feature of my 2.6.12 kernel. Also, I have both of my CD drives with SCSI emulation support enabled, so my drives are:

1. /dev/cdroms/cdrom0, /dev/sr0, /dev/scd0
2. /dev/cdroms/cdrom1, /dev/sr1, /dev/scd1

My fstab lines for these drives are as follows:

/dev/cdroms/cdrom0              /mnt/dvd        auto            noauto,user,ro                                  0 0
/dev/cdroms/cdrom1              /mnt/cdrw       auto            noauto,user,ro                                  0 0
/dev/sr1                /media/cdrecorder       auto    user,exec,noauto,managed 0 0
/dev/sr0                /media/cdrom            auto    user,exec,noauto,managed 0 0

Those last two lines were added automatically be udev.

Here are the few example attempts of mounting:

# mount -t iso9660 /dev/sr0 /mnt/tmp
mount: block device /dev/sr0 is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/sr0,
       or too many mounted file systems
# mount -t iso9660 /dev/scd0 /mnt/tmp
mount: block device /dev/scd0 is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/scd0,
       or too many mounted file systems
# umount /mnt/dvd
umount: /mnt/dvd: not mounted
# mount /dev/cdroms/cdrom0
Segmentation fault
# ls /mnt/dvd
#

As you can see, none of these attempts are successful.

Lastly, this is what lshw returns when dealing with my CD drives:

           *-ide:1
                description: IDE Channel 1
                physical id: 1
                bus info: ide@1
                logical name: ide1
                clock: 33MHz
              *-cdrom:0
                   description: IDE CD-ROM
                   product: SAMSUNG DVD-ROM SD-616Q
                   physical id: 0
                   bus info: ide@1.0
                   logical name: /dev/hdc
                   version: F401
                   capabilities: packet atapi cdrom removable nonmagnetic dma lba iordy
                   configuration: mode=udma2
              *-cdrom:1
                   description: IDE CD-ROM
                   product: ATAPI CD-RW 52X24
                   physical id: 1
                   bus info: ide@1.1
                   logical name: /dev/hdd
                   version: F.CZ
                   capabilities: packet atapi cdrom removable nonmagnetic dma lba iordy
                   configuration: mode=udma2
     *-scsi:0
          physical id: 1
          logical name: scsi0
          capabilities: emulated
        *-cdrom
             description: DVD reader
             product: DVD-ROM SD-616Q
             vendor: SAMSUNG
             physical id: 0.0.0
             bus info: scsi@0:0.0.0
             logical name: /dev/cdrom2
             logical name: /dev/dvd1
             logical name: /dev/scd0
             logical name: /dev/sr0
             version: F401
             capabilities: removable audio dvd
             configuration: ansiversion=2
     *-scsi:1
          physical id: 2
          logical name: scsi1
          capabilities: emulated
        *-cdrom
             description: CD-R/CD-RW writer
             product: CD-RW 52X24
             vendor: ATAPI
             physical id: 0.0.0
             bus info: scsi@1:0.0.0
             logical name: /dev/scd1
             logical name: /dev/sr1
             version: F.CZ
             capabilities: removable audio cd-r cd-rw
             configuration: ansiversion=2

Is there a solution for this problem?

[lakerdonald]

The first two sound like a function of you specifying "-t" on the command line. Try omitting the iso9660 for those two and let mount do its thing.

[Kenji Miyamoto]

# mount /dev/sr0
mount: block device /dev/sr0 is write-protected, mounting read-only
mount: you must specify the filesystem type
# mount /dev/cdroms/cdrom0

The second command never did anything; it just froze the console. Even two hours later, nothing happens.

I also tried it out in GDB, with the "/media/cdrom" mountpoint specified, and nothing different happened. The drive didn't spin up either time.

[drakebasher]

On my system, /dev/cdrom is symbolic link to /dev/hdd. Is your /dev/cdroms/cdrom0 pointing to the right device? Do:

ls -l /dev/cdroms/cdrom0

[Kenji Miyamoto]

$ ls -l /dev/cdroms
total 0
lrwxrwxrwx  1 root root 6 Jul  8 06:50 cdrom0 -> ../hdc
lrwxrwxrwx  1 root root 6 Jul  8 06:50 cdrom1 -> ../hdd

[Kenji Miyamoto]

It seems to work with my 2.6.12-gentoo-r4 kernel if I don't use xdm to boot up. I really would like to start up X without having to type "startx", though.

[lordnothing]

turn off ide-scsi.. it's not needed.. also, go through each of the options in the kernel for CDROM devices and figure out whether you actually need them or not.. extra crap generates more overhead.

the segmentation fault that mount gave once has me worried. try recompiling it with just -O1 -pipe as your CFLAGS... also, if your computer is starting to become a bit aged, i would suggest running memtest86 on it to see if the SIGSEGV was caused by bad memory..

[Kenji Miyamoto]

I haven't really gotten it to mount at /dev/cdroms/cdromn. Somehow, mounting in a terminal works perfectly, but only on the SCSI CD-ROMs. When trying to mount any form of my first CD drive in KDE, it stalls.

I can unmount the drives without a problem, though.

EDIT: /dev/hdc or hdd stalls even if there isn't a CD in the drive.

[Kenji Miyamoto]

It seems that whenever I start my system up and these lines appear at the bottom of my /etc/fstab, the problems occur:

/dev/sr1                /media/cdrecorder       auto    user,exec,noauto,managed 0 0
/dev/sr0                /media/cdrom           auto    user,exec,noauto,managed 0 0

No matter how I change them, the drives just won't mount. The two times my system failed to create these, I was forced to, and without the "exec" flag. The drives, as sr0 and sr1, did mount when the command was invoked from a console. Now that udev has created these lines at the end, the drives aren't able to do a single thing with data.

When I was on a 2.6.11-gentoo-r9 kernel, I never had a single bit of trouble with this, with or without xdm; in or out of a console. I really wonder what has changed as far as CD handling from that kernel to 2.6.12.

I hope this helps, since it's the only thing I can say, now.

[Kenji Miyamoto]

Removing SCSI emulation from those two drives fixed it, but now how I am supposed to burn CDs?