Re: [PATCH v3 4.17] inotify: Add flag IN_EXCL_ADD for inotify_add_watch()

[Jan Kara <jack@suse.cz>]

On Wed 30-05-18 22:03:35, Amir Goldstein wrote:
> On Wed, May 30, 2018 at 7:04 PM, Jan Kara <jack@suse.cz> wrote:
> > On Wed 30-05-18 18:40:27, Amir Goldstein wrote:
> >> On Wed, May 30, 2018 at 4:35 PM, Henry Wilson <henry.wilson@acentic.com> wrote:
> >> > On 30/05/18 14:01, Jan Kara wrote:
> >> >>
> >> >> Thanks. The patch looks good. I've added it to my tree. BTW, do you plan
> >> >> on
> >> >> working on a similar addition to fanotify?
> >> >>
> >> >>                                                                 Honza
> >> >>
> >> >
> >> > Ah that's grand, I'm glad to have helped to improve things.
> >> > I'm not familiar with fanotify, however a quick look at fanotify_user.c
> >> > suggests that a similar approach may be taken by modifying:
> >> >
> >> > if(!fsn_mark) {
> >> >         ...
> >> > }
> >> > else if (create) {
> >> >         return -EEXIST;
> >> > }
> >> >
> >> > in both fanotify_add_vfsmount_mark() and fanotify_add_inode_mark()
> >> >
> >>
> >> I think that was a yes/no question and I interpret your answer as no??
> >>
> >> Anyway, another yes/no question:
> >> Can you write a simple LTP test to verify the new API?
> >>
> >> I reccon Jan was also expecting an actual patch posted to man pages
> >> maintainer (and linux-api, which was not cc'ed on the latest patch).
> >
> > Yes, and I think Henry is about to post it, just didn't get to it yet.
> >
> >> About the fanotify change, since fanotify API does have 'flags' separate
> >> from 'mask', I am not sure if FAN_MARK_EXCL_ADD would be the
> >> best flag name?? Perhaps FAN_MARK_CREATE? FAN_MARK_NEW?
> >> not sure.
> >
> > Yes, for fanotify we could choose a different name.
> >
> >> But also, I did not get a chance to comment about the chosen inotify
> >> flag name that the lexical proximity to IN_EXCL_UNLINK is a bit odd
> >> considering that _EXCL_ mean two completely different things.
> >>
> >> Should we maybe re-consider the chosen flag name?
> >
> > I'm open to that, I have the patch just sitting in an internal branch for
> > now. Do you have a better suggestion? Maybe since we already have
> > IN_MASK_ADD, we could call it IN_MASK_CREATE? And then FAN_MARK_CREATE for
> > fanotify_mark(2)?
> >
> 
> I like that naming.
> 
> Thinking forward, since we don't have many reserved bits left in inotify mask,
> we should return -EINVAL for both IN_MASK_ADD and IN_MASK_CREATE
> (they don't make sense together anyway), so we may re purpose the flag
> combination in the future for something else.

Good point, I'll update the patch.

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