Not really sure where to start but I had an ext3 fs mounted as /home on /dev/sdb3. I then attempted to create a swap partition on that running:
mkswap /dev/sdb3 1000000 STUPID!!

I then thought to run fsck but it warned me about running on a mounted file system.
I then issued : umount /home

This has since unmounted it but now I cannot remount it. Please see the following disk stats:

df -k

Filesystem 1k-blocks Used Available Use% Mounted on
/dev/sdb5 381139 305288 56173 85% /
/dev/sda1 46636 34978 9250 80% /boot
none 579968 0 579968 0% /dev/shm
/dev/sdb1 3020140 992068 1874656 35% /usr
/dev/sdb6 27521840 17024156 9099632 66% /var

mount

/dev/sdb5 on / type ext3 (rw)
none on /proc type proc (rw)
/dev/sda1 on /boot type ext3 (rw)
none on /dev/pts type devpts (rw,gid=5,mode=620)
none on /dev/shm type tmpfs (rw)
/dev/sdb1 on /usr type ext3 (rw)
/dev/sdb6 on /var type ext3 (rw)

fdisk -l

Disk /dev/sda: 255 heads, 63 sectors, 1106 cylinders
Units = cylinders of 16065 * 512 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 6 48163+ 83 Linux

Disk /dev/sdb: 255 heads, 63 sectors, 4427 cylinders
Units = cylinders of 16065 * 512 bytes

Device Boot Start End Blocks Id System
/dev/sdb1 * 1 382 3068383+ 83 Linux
/dev/sdb2 383 636 2040255 82 Linux swap
/dev/sdb3 637 897 2096482+ 83 Linux
/dev/sdb4 898 4427 28354725 5 Extended
/dev/sdb5 898 946 393561 83 Linux
/dev/sdb6 947 4427 27961101 83 Linux


major minor #blocks name rio rmerge rsect ruse wio wmerge wsect wuse running use aveq

8 0 8885248 sda 58 166 448 120 17 10 54 90 0 180 210
8 1 48163 sda1 39 61 200 60 17 10 54 90 0 120 150
8 16 35563520 sdb 137142 341331 3688992 2831030 159173 425951 4062706 20847160 0 2539090 23947020
8 17 3068383 sdb1 4847 2815 60770 19210 1738 4063 46960 31650 0 24760 51080
8 18 2040255 sdb2 3270 0 26160 11040 19037 74047 752824 15381320 0 1109130 15651210
8 19 2096482 sdb3 14865 235285 2000642 89900 28 4 232 20 0 45330 89920
8 20 1 sdb4 0 0 0 0 0 0 0 0 0 0 0
8 21 393561 sdb5 11258 11398 45314 26410 30815 81176 224402 353220 0 67790 379620
8 22 27961101 sdb6 102868 91635 1555642 2684370 107555 266661 3038288 5080960 0 1396020 7775050

Well, It might sounds cheap, but have you tried a powercycle ? (I mean power off, unplug, wait 10 sec, replug and reboot).
I also had made my controller mad and it was the only way to set it back to normal, without destroying everything with fsck.

I did but I was afraid that it would not even boot.
Even though I've only screwed with /home...do you think it would give me a problem?
Now that I've unmounted that volume, do you think this might still work?