Very strange partition size problem (solved)

[sman]

I already have my Gentoo system installed but since partitioning is mostly related to installations I post this here. My problem is that the last of four partitions on my 200 GB Barracuda (SATA) HD is 95 GB but shows as 30 GB. The first partition is a boot partition (40 MB), then 500 MB swap, then 100 GB and finally the problematic 95 GB. I didn't notice this problem immediately since creating the partitions with cfdisk went fine but when I ran cfdisk llater it showed the last partition as much smaller than it should be and then followed by "unusable" space (I cannot remember exactly what the size shown then was) - I then tried deleting the last partition and creating it again. cfdisk then showed that it was 95 GB and no unusable space, which seemed plausible - then I ran mkfs.ext3 and mounted the partition and noticed that df showed its size as 30 GB. I took a look at dmesg and found the following:
EXT2-fs warning (device sda4): ext2_fill_super: mounting ext3 filesystem as ext2
which made me try mkfs.ext2 but that was to no avail. I'm currently running a 32 bit installation on my Athlon 64 and would like to try 64 bits on that partition and thus ext2/3 is my only option at the moment (according to the Gentoo AMD 64 docs) so I haven't tried creating a ReiserFS partition on it. Does anybody know how to solve this problem? I might add that it's a brand new HD so it has never been partitioned in any other way.

Edit: My problem is getting even stranger - I just tried mkfs.ext3 again without doing any other changes and now got the size to 87GB, 33MB used (even though there's nothing on the partition) and 83 GB available. What could cause this?

SOLVED! I just learnt a little bit more about cfdisk, fdisk and df and now know that the sizes are the same and the use of space is caused by the journaling.

[tukachinchila]

When you run cfdisk, do all 4 partition types show up as "Primary"? If so, then any extra available space will show up on your harddrive as unusable since you can only have 4 Primary partitions. If you wanted to have more than 4 partitions, you can only have 3 Primary partitions, and the rest will be "Extended" partitions.
Could it be that when you originally partitioned your HD, you manually set the amount of space for the 4th partition instead of letting cfdisk appropriate the remaining free space?
I think it could also be that your BIOS may not support HDs that are that big?
I also wonder, if you unmount the 4th partition, then view the contents of that directory, is it empty?

[sman]

Thanks for reminding me about that issue with only four primary partitions being possible - that explains why I had the unusable space before. For some reason all remaining disk space wasn't used when I initially created the last partition during installation - that's what I intended to do but maybe I made a mistake or something else went wrong. However, that problem was obviously solved when I deleted the last one and then created it again since there's no unusable space anymore but the size of the formatted partition still is smaller than it should be - df -h states that the size is 87 GB, 33 MB used and 83 GB available even though there's nothing on that partition and cfdisk states that its size is 95 GB (so the sums really don't add up).

Edit: I just tested mkreiserfs and then the size of that partition became 89GB, 33 MB used, 89GB available. So in that case the sums add up but it's still not 95GB as reported by cfdisk (and I still need to get it as ext2/3 because I intend to make an amd64 installation on it and that's what the Gentoo handbook recommends).