Re: [PATCH] ext4: add generic uevent infrastructure

[Jan Kara <jack@suse.cz>]

On Tue 19-11-13 02:25:01, Christoph Hellwig wrote:
> On Tue, Nov 19, 2013 at 12:36:21PM +1100, Dave Chinner wrote:
> > I certain agree with that. I'd also like to see ENOSPC notifications
> > as that would obliviate the need for distros like RHEL to ship
> > systemtap scripts to generate such notifications for admins....
> 
> The ENOSPC case would be a natural tag on to Jan's quota notification,
> and I have a vague memory that someone started implementing it or
> at least talked about it.
  Yes, quota netlink interface is technically very easy to extend to also
provide ENOSPC notifications. It's just that the name of generic netlink
family is 'VFS_DQUOT' so ENOSPC notifications do not fit very well with
that name but it isn't too bad either.

> > > Also Jan Kara has done quota netlink notifications a while ago, which
> > > fit into the same sort of niche.
> > 
> > The question I'm asking is whether we really want a new interface
> > for these events? Shouldn't we really try to use an existing
> > filesystem event interface for generating these events
> 
> Good quetion, and the quota netlink notifications would be the natural
> place to tag on at least some of this.
> 
> > (e.g.
> > fanotify) rather than adding yet another disjoint filesystem event
> > interface to the kernel?
> 
> It needs to be a per-fs interface, and as Dmitry pointed out fanotify
> is a per-file one.
  I agree fanotify is really a bad fit.

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR