Re: File change notification

[Michael Clark]

On 01/01/04 02:48, Rüdiger Klaehn wrote:
> Javier Fernandez-Ivern wrote:
>
> > Rüdiger Klaehn wrote:
> >
> > > I have been wondering for some time why there is no decent file 
> > > change notification mechanism in linux. Is there some deep 
> > > philosophical reason for this, or is it just that nobody has found 
> > > the time to implement it? If it is the latter, I am willing to 
> > > implement it as long there is a chance to get this accepted into the 
> > > mainstream kernel.
> >
> >
> >
> > Well, there's fam.  But AFAIK that's all done in user space, and your 
> > approach would be significantly more efficient (as a matter of fact, 
> > fam could be modified to use your change device as a first level of 
> > notification.)
> Fam is a user space library that has some nice features such as network 
> transparent change notification. It currently uses the dnotify mechanism 
> if the underlying kernel supports it, but as I mentioned the dnotify 
> mechanism requires an open file handle and works only for single 
> directories. If the underlying os does not support dnotify, fam resorts 
> to polling for file changes (yuk!).

Have you had a look at dazuko. It provides a consistent file access
notification mechanism (and also intervention for denying access) across
linux and freebsd. It is currently being used by various on-access
virus scanners. It is under active development and supports 2.6 (and 2.4)

http://www.dazuko.org/about.shtml

Seems like a good idea. I've always thought it would be nice to use
something like this to maintain a dynamic locatedb (among many other
potential uses).

~mc

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/