As someone who recently did a comparative study of 
UNIXFS vs. FFS vs. LFS, I would recommend the following
URL:

http://www.scriptics.com/people/john.ousterhout/seltzer.html

Remember that the LFS's overhead is mainly with it's segment cleaning
mechanism. As a result, LFS requires a great deal of free space(50%+) on
the partition in order for it to operate efficiently. In fact, the ehanced
FFS rivals LFS anyday regardless of the fullness of disk.

-jake