Re: FAN_OPEN_EXEC event and ignore mask

[Matthew Bobrowski <mbobrowski@mbobrowski.org>]

On Mon, Nov 05, 2018 at 09:41:47AM +0100, Jan Kara wrote:
> On Sat 03-11-18 11:34:13, Matthew Bobrowski wrote:
> > On Fri, Nov 02, 2018 at 01:50:00PM +0100, Jan Kara wrote:
> > > On Thu 01-11-18 16:45:47, Amir Goldstein wrote:
> > > > Permission events cannot
> > > > be merged, but man page doesn't say anything about that.
> > > > It might be worth dropping a note about OPEN_EXEC_PERM
> > > > that it could be expected to appear together in the same permission
> > > > event with OPEN_PERM and user response will apply to both.
> > > 
> > > Umm, I'd actually prefer if the OPEN_PERM and OPEN_EXEC_PERM events didn't
> > > get merged. The overhead is just an additional call to fsnotify() to find
> > > out one of the events is uninteresting (realistically, 99% of users will be
> > > looking OPEN_PERM or OPEN_EXEC_PERM but not both) and it just keeps things
> > > simple in the API. I understand that it may seem somewhat unexpected that
> > > single file open will generate two different fsnotify permission events
> > > (again 99% users won't observe this anyway) but if we start "merging"
> > > permission events I think we open more space for confusion - like when
> > > event arrives with some bits trimmed due to ignore mask masking bits out or
> > > what not. What do you think Amir?
> > 
> > This is something that I was going to bring up in my response yesterday,
> > however I wasn't sure how you guys would take it. In my opinion, I think
> > if we did merge the two open permission events then it would be
> > contradicting with all the existing comments and code related to the
> > permission events that we have scattered around the API. Thus, I'm in
> > favour of adding the additional fsnotify()/fsnotify_parent() calls to
> > minimise any potential confusion in regards to permission events being
> > merged moving forward.
> 
> Yes, so please update your patch adding FAN_OPEN_EXEC_PERM to send this
> event separately from FAN_OPEN_PERM. Thanks!

OK, great. I will send through the updated patch series shortly.

-- 
Matthew Bobrowski