Re: [PATCH] fanotify: introduce event flags FAN_EXEC and FAN_EXEC_PERM

[Steve Grubb <sgrubb@redhat.com>]

On Thursday, July 19, 2018 6:17:08 AM EDT Jan Kara wrote:
> So fanotify is a filesystem event notification API. For filesystem, open
> and read are fundamentally different events and as such we have different
> FAN_OPEN and FAN_ACCESS events in the API. The only disputable events we
> have in the API are FAN_CLOSE_WRITE vs FAN_CLOSE_NOWRITE - from fs POV
> there's no big difference. But at least this is 100% reliably (unlike
> FMODE_EXEC) telling you whether the user was able to modify the file or not
> and it caters to one of the use cases this API has been created for -
> virus scanners, file caching daemons, ... - i.e., triggering specific
> actions based on file contents.

Would it be more acceptable to not add FAN_EXEC_PERM on the front end where 
you ask for it at fanotify_mark. But rather add only FAN_EXEC? This would 
reduce the proposed API and just turn it into additional metadata about 
events that are already being requested. This ways you can do something like:

mask = FAN_OPEN_PERM | FAN_EXEC;

and then pass that to fanotify_mark. It would not affect old programs because 
they simply wouldn't ask for the bit. Would this be more palatable?

Best Regards,
-Steve