FS callback routines

[Sean R. Bright]

	Ok, before I begin, don't shoot me down, but I had an idea for a kernel
modification and was wondering how feasible the group thought it was.

	I was writing a user space application to monitor a folder's contents.  The
folder itself contained 100 folders, and each of those contained 24 folders.
While writing the code to traverse the directory structure I realized that
instead of my software figuring out when things change, why not just have
the fs tell my application when something was updated.  For example, say we
had a function called watch_fs(), that took an inode reference and a
function pointer and maybe a bitmask of events to watch for.  When that
inode (or its children) were changed, why couldn't the fs code call the
callback function I specified?

	I have no idea how expensive this would be or if its even worth it at this
point.  It also wouldn't be portable at all considering that I know of no
other OS that does this (could be wrong).

	Like I said, I am not asking that this be (necessarily) implemented, I am
just curious as to what the percieved performance ramifications would be if
it were to implemented, say, by a virgin kernel developer ;)

	Thanks,
	Sean
	[e-mail]