Concurrency in JFFS2?

[Martin Galvan]

Hi everyone! I'm working on porting F2FS from Linux based on the JFFS2
port Sebastian did. When inspecting the code I found that
libfs/jffs2/include/linux/mutex defines struct mutex to be empty, and
all the mutex-related functions to do nothing.

This seems to imply that there's no concurrency management in the
JFFS2 code. Is this intentional? Should I do the same when porting
F2FS?