[FS] New monitor framework in 2.6.10?

[FS] New monitor framework in 2.6.10?

[Stephan Menzel]

Hi,

i'm maintaining a kernel patch which is monitoring file system activity 
underneath a special directory tree and reporting occuring events via a 
character device to userland where it is processed.
Right now, this patch works via a number of hooks in fs/read-write.c and 
fs/namei.c. 
This is not really efficient at the moment because this way I get an event for 
any written block and not per file which can slow things down a lot.
A couple of days ago I heard rumours about a new feature in 2.6.10 which will 
be exactly for this kind of purpose. Some kind of monitor frameworks that can 
generate events for all sorts of things. Sorry, I don't know any more about 
it.
Is that true? 
Would that be suitable for my task?
And where can I get information about it?

Greetings...

Stephan

Re: [FS] New monitor framework in 2.6.10?

[Jan Engelhardt]

>Hi,
>
>i'm maintaining a kernel patch which is monitoring file system activity
>underneath a special directory tree and reporting occuring events via a
>character device to userland where it is processed.
>Right now, this patch works via a number of hooks in fs/read-write.c and
>fs/namei.c.
>This is not really efficient at the moment because this way I get an event for
>any written block and not per file which can slow things down a lot.
>A couple of days ago I heard rumours about a new feature in 2.6.10 which will
>be exactly for this kind of purpose. Some kind of monitor frameworks that can
>generate events for all sorts of things. Sorry, I don't know any more about
>it.

Wasnot it called System Call Auditing and/or Filesystem hooks?

>Is that true?
>Would that be suitable for my task?
>And where can I get information about it?

One or the other was present in SUSE's 2.4.20/.21 kernels and one is in 2.6.x
-- and from what I have seen, they're just hooks, i.e.

if(hook != NULL) { hook(fd, buf, size); }

That's the most efficient thing you can have (in a function). It's only a
question whether it is in the right function, then.



Jan Engelhardt
-- 
Gesellschaft für Wissenschaftliche Datenverarbeitung
Am Fassberg, 37077 Göttingen, www.gwdg.de

Re: [FS] New monitor framework in 2.6.10?

[Stephan Menzel]

Am Montag, 15. November 2004 11:23 schrieb Jan Engelhardt:
> > will be exactly for this kind of purpose. Some kind of monitor frameworks
> > that can generate events for all sorts of things. Sorry, I don't know any
> > more about it.
>
> Wasnot it called System Call Auditing and/or Filesystem hooks?

Well, that's what I'd like to know.
System Call Auditing just yielded a few google results but it doesn't seem to 
me like a well documented feature. More like people asking for it.

> One or the other was present in SUSE's 2.4.20/.21 kernels and one is in
> 2.6.x -- and from what I have seen, they're just hooks, i.e.
>
> if(hook != NULL) { hook(fd, buf, size); }
>
> That's the most efficient thing you can have (in a function). It's only a
> question whether it is in the right function, then.

Indeed.
And just that made me hope there is something like an auditing or monitoring 
framework just like for instance a accessible struct with several function 
pointers where one could insert funtions to be processed whenever event x 
occurs. This kind of thing yould be maintained by the kernel developers who 
could put the hook just in the right place and the 'user' (which would be me 
in that case) could be sure that his function would be called in the right 
time and from the right place.
That would be nice.

Greetings...

Stephan

Re: [FS] New monitor framework in 2.6.10?

[Stephan Menzel]

Am Montag, 15. November 2004 11:42 schrieb Stephan Menzel:
> > Wasnot it called System Call Auditing and/or Filesystem hooks?
>
> Well, that's what I'd like to know.

And I just found an answer:

inotify. http://lwn.net/Articles/104312/ 
That looks fine to me.
What happened to this? It's not in the vanilla 2.6.9 as far as I can see. Will 
it be in 2.6.10?

Greetings...

Stephan

Re: [FS] New monitor framework in 2.6.10?

[Paolo Ciarrocchi]

On Mon, 15 Nov 2004 13:44:50 +0100, Stephan Menzel
<stephan42@chinguarime.net> wrote:
> Am Montag, 15. November 2004 11:42 schrieb Stephan Menzel:
> > > Wasnot it called System Call Auditing and/or Filesystem hooks?
> >
> > Well, that's what I'd like to know.
> 
> And I just found an answer:
> 
> inotify. http://lwn.net/Articles/104312/
> That looks fine to me.
> What happened to this? It's not in the vanilla 2.6.9 as far as I can see. Will
> it be in 2.6.10?

Yes, it's already in the -bk snapshot.

-- 
Paolo
Personal home page: www.ciarrocchi.tk
Picasa users groups: www.picasa-users.tk
join the blog group: http://groups-beta.google.com/group/blog-users