GSoC: File system changes notification

[Ilya Putsikau]

Hi all,

This summer I'll add file system notification mechanism that works
around limitations of kevent. It has the same limitation as Linux'
dnotify once had: file or directory should be opened to monitor
changes, preventing file system unmounting. Most of the applications
in FreeBSD currently use polling because of this limitation (gamin,
kde).

I'll reuse existing kevent framework by attaching kevent listeners to
vnodes on creation, implementation is to be kernel level, have user
level inotify API compatibility and can be used to implement inotify
support in linuxulator.