If you don't like the numbers, send a bug report to the Linux kernel folks. Note that doing this in a way that people expect is not simple.....
Hi Jörg, I guess this is not a kernel problem. Mkisofs runs entirely in user space and its output is a single file. This file is incorrect. Volume Space Size field of Primary Volume Descriptor should be increased according to the size of previous session(s). Why do you think kernel guys can do something to fix this bug? :-o Regards Gabor p.s. I wish you Merry Christmas and Happy New Year. :-)