Sorry; I did indeed forget the "/dev/sdb1" when I first specified the tune2fs command.

The tune2fs utility has existed for many years and is delivered with just about every version of Linux that's intended for desktop or server use. It should work fine between Ubuntu 9.04 and 8.10, at least for ext2 and ext3 filesystems. (I'm not sure about the exact milestones in ext4fs developments with respect to those two Ubuntu versions.)