Comment 43 for bug 431055

@Daniel Ellis

I have seen such messages myself.
It smells like kernel bug, but here a reboot, will make the disk readable again.
So, did you try to reboot?

Does this happens with all disks.
From now on, pay carefull attention to dmesg, and to
blkid /dev/sr0

The fact that blkid returns nothing means that it can't detect valid FS on the disk, which can be caused ether by kernel bug/bad device/bad media.

So test with few disks, of several types if possible.