Different, I think...
When I partitioned my drive a couple of months ago I prepared it so that I easily could install Linux on it. I made a 1.5 Gb partition for 'root' (Apple_UNIX_SVR2) and a 50 Mb partition for the swap. Now, I'm running out of space on my other partitions and it would be nice to use the 'root partition' for my Mac OS-files, since I don't have Linux installed. How do I format the partition and make it mount automaticly?
I had a similar predicament a few months back, however, my Linux partition still had Linux on it. After a crash one of the Gnome files was damaged and LinuxPPC 2000 would discontinue booting and tell me to run fsck. After it didn't fix the problem I had to reluctantly hose the Linux partition. The Linux distribution I have is LinuxPPC 2000. My Linux CD is a bootable CD and it boots into Linux and an installer. One of the installer programs, Perldisk, allows you to change the partition type (LinuxPPC, Apple_HFS, Apple_UNIX_SVR2, etc...). Check any documentation that may have come with your distribution. If you have the same distribution or one with a program that allows you to do this, just change the partition type back to "Apple_HFS". Make note of the volume, i.e. /dev/disk1s6 etc... Next boot into Mac OS 9.1 or Mac OS X, start up the Disk Utility program. You should see a disk icon somewhere with either "/dev/disk1s6" or "1s6", assuming that is the volume to be formatted. Then select that drive and format/erase the volume. I was unsuccessful in using Apple's Disk utility program alone in changing the partition type without reformatting the entire drive, which is bad if you still need or are using the other partitions on that drive. Perhaps someone else here has a better method for solving your problem.

Blue & White 400MHz G3, 640MB RAM, 12GB IBM UltraATA, 18GB IBM UltraSCSI, 100MB ZIP, Adaptec 2930 SCSI card, Mac OS 9.1, Mac OS X 10.0.4