[arch-general] Problems with mounting linux partition with gid

I have no problems mounting via fstab my vfat partitions with an option like 'gid=100'. However, I can't seem to get that to work with a Linux data partition. That partition is formatted ext3. I also tried 'grpid=100', to no avail. Dmsg gives me an 'Unrecognized mount option' error with these. How do I create a Linux data partition that's fully accessible to me, as user, after boot?