===== File system changes notification =====

Most of the applications in %%FreeBSD%% currently use polling because of limitations of kevent-based file change monitoring (gamin, kde). Kevent approach has the same limitation as Linux' dnotify once had: file or directory should be opened to monitor changes, preventing file system unmounting. I propose to develop a kernel level file system changes notification mechanism for %%FreeBSD%% overcoming this limitation.

==== Milestones ====
  - Very simple notification mechanism. Create user space utility for debugging printing all events. Pass all events to user space, attach to all vnodes on creation
  - Create a library based on the utility. Add client sessions, distribute events to all clients. Add main operations to the library (initialization, addition notification, deletion of notification)
  - Add cookies to VFS_KNOTE_LOCKED to make several notifications during move or rename part of single operation. Add path caching necessary to return previous path expected by rename and delete operations.
  - Clean and test code before mid-term evaluation. Code is to be useful but with limitations.
  - Filter events. Attach to vnodes client is interested in. Attach not only on vnode creation but also to already existing vnodes. 
  - Add access permissions checks. Add sysctl to enable access permissions check. Run benchmark to measure its overhead.
  - Ensure source level compatibility with inotify. Interface is to be very similar from the beginning. Reuse tests from linux.
  - Add linuxulator support. Linuxulator support is just a wrapper mapping linux' syscalls to native device ioctls.