I checked the man for resize2fs and the copyright notice is from 1998, so I guess that even back in the day was possible to grow ext2 filesystems. Shrinking them I don't know, it's still a feature that not all filesystems supports to this day.
If you think about it extending a filesystem is pretty easy: you just have to write in the filesystem control structures that you have more blocks available to store data than what originally planed. The problem of course is shrinking, since you have to relocate the blocks that goes beyond the new partition size.
If you think about it extending a filesystem is pretty easy: you just have to write in the filesystem control structures that you have more blocks available to store data than what originally planed. The problem of course is shrinking, since you have to relocate the blocks that goes beyond the new partition size.