Comment 13 for bug 397734

(In reply to comment #3)
> No much objection, but what happens if an application has an opened file on the
> cdrom, or even worse if a file is loop mounted from the cdrom.
>
> In my opinion this can cause very nasty consequences (lock-ups)

It won't cause lock-ups except for the process in question - not for the system anyway. And properly written apps can deal with it, it's just IO errors.

FWIW, what happens today is that if the underlying device goes away, some part of userspace will lazy unmount the device. Ideally the kernel would force unmount filesystems (causing ENXIO (for fds) and SIGBUS (for mapped files) on IO), tear down RAID, LVM, device-mapper etc. but that is not how things currently works. Instead you get stale mount points, broken symlinks in sysfs and so on. My view is that it's a kernel bug, others may agree or disagree. We may end up fixing the kernel, we may not.

BTW, this is not very different from yanking a USB device or pulling out a CF card. And we deal relatively well with this already.