The patch below removes some dead code and nonsense code.
The part that changes behaviour is

 -       if (sbi->s_cruft == 'n' &&
 -           (volume_seq_no != 0) && (volume_seq_no != 1)) {
 -               printk(KERN_WARNING "Warning: defective CD-ROM "
 -                      "(volume sequence number %d). "
 -                      "Enabling \"cruft\" mount option.\n", volume_seq_no);
 -               sbi->s_cruft = 'y';
 -       }

that has already bitten lots of people.

Nothing is wrong with a volume sequence number different from 0 or 1.
(Cf. Ecma-119.pdf, Sections 4.17, 4.18, 6.6.)