If it feels a bit too much I suggest you look a few commits back before I added write support, it was still simpler then. Eventually I'll have both the lite and full versions, with generous comments.
There's also /sys/src/lib9p/ramfs.c but its usage of 9pfile(2) obstructs a lot of important stuff.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko