How to access CDROM in a simple Linux initrd filesystem made by busybox?

Question

Here's my situation:

I made a simple bootable ISO file for x86-64 architecture using 6.3-rc1 Linux bzimage, a simple initrd filesystem made by busybox and grub.

I boot it up with virtualbox, and I tried to mount the /dev/sr0, it shows error mount:mounting /dev/sr0 on /mnt/cdrom failed: Invalid argument. Also, the kernel shows error: [ timestamp] /dev/sr0: can't open blockdev So my question is that how can I access the CDROM in this situation? I trid googled but found nothing useful.

Thanks in advance!

Answer 1

The reason why I can't mount the /dev/sr0 in initrd mode is that The configuration file for the kernel I compiled sets the iso9660 file system to "m", and I didn't load the iso file system module.

So after I load the isofs.ko, problem solved.