Re: [Ksummit-discuss] [TECH TOPIC] Linux kernel SMB server (CIFSD)

[Sergey Senozhatsky <sergey.senozhatsky@gmail.com>]

On (07/24/19 13:50), Amir Goldstein wrote:
[..]
> I don't see a problem with exporting those symbols.
> As a matter of fact, I have a plan to use them also from overlayfs.
> At the time that Jeff posted his patches, there was no active fsnotify
> maintainer.

Cool.

> Jeff, did you abandon this effort for nfsd?
> 
> >
> > I even looked at LSM hooks, because they do what we need - invoke
> > creat, open, truncate, chmod, chown, unlink, callbacks. But, first,
> > I do realize that LSM was not meant to be used as some sort of fsnotify
> > replacement, and, second, LSM symbols are not exported anyway :)
> >
> 
> fsnotify could actually be called from LSM hooks, see:
> https://github.com/amir73il/linux/commits/fsnotify_dirent_perm
>
> It may or may not be clear to you, but what you get extra from fsnotify
> compared to using bare LSM hooks is:

Oh yeah, LSM does not really fit. I looked at it just out of curiosity.

> - Minimal performance overhead for a non-marked object
> - Ability to subscribe/unsubscribe to certain events dynamically

Absolutely, we need to "subscribe/unsubscribe dynamically".

> - Manage multiple subscriber instances (groups), like one per SMB session

We need this as well, you're right.

> - Queuing infrastructure for async events if you need it

	-ss