Since fuse is being mentioned here .... I needed to do a fuse module recently. The standard Linux fuse library is quite badly designed. Turns out Russ's fuse library is about as good as you can get given the limitations of the kernel interface for fuse. I really like it in fact. It made my library development dead simple.
So if you're going to do anything with fuse, use the p9p version. It's great. I did beat on Russ's code a bit to make it work without requiring p9p libraries (long story ...). It was a trivial set of changes which anyone can easily do. ron