Re: Inotify Kernel Question

[Robert Love <rml novell com>]

On Wed, 2005-02-16 at 00:44 -0500, Ken Stanley wrote:

> I'm just curious why inotify isn't able to be built as a kernel module?
> It would seem with the steady development on inotify, that builing it
> into the kernel just isn't prudent, and causes excess work to be done by
> continually having to rebuild/change-out kernels, when it could be built
> as a module, and inserted into any existing/working kernel. I know this
> may seem like a trivial question, but you know how curiousity can be.

Curiosity, my friend, killed the cat.

Unfortunately, inotify cannot be built as a kernel module because it
hooks directly into non-modular code, primarily low-level VFS functions.
When the module is not loaded, the function pointers would dangle and
cause massive deforestation when dereferenced.

Of course, we could design a complicated plugin system that managed all
of this and allowed for hot-swappable and dynamic file notification
systems to be loaded and unloaded.  The generic filesystem notification
layer I did is a great start to this.  But I think that is overkill and
extraneous overhead and I suspect that the kernel community would agree.
So no module.

	Robert Love