On Fri 04-01-19 13:42:33, Amir Goldstein wrote:
> On Fri, Jan 4, 2019 at 12:57 PM Jan Kara <jack@xxxxxxx> wrote:
> > > @@ -145,12 +146,38 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
> > > marks_ignored_mask |= mark->ignored_mask;
> > > }
> > >
> > > + test_mask = event_mask & marks_mask & ~marks_ignored_mask;
> > > +
> > > + /*
> > > + * dirent modification events (create/delete/move) do not carry the
> > > + * child entry name/inode information. Instead, we report FAN_ONDIR
> > > + * for mkdir/rmdir so user can differentiate them from creat/unlink.
> > > + *
> > > + * For backward compatibility and consistency, do not report FAN_ONDIR
> > > + * to user in legacy fanotify mode (reporting fd) and report FAN_ONDIR
> > > + * to user in FAN_REPORT_FID mode for all event types.
> > > + */
> > > + if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
> > > + /* Do not report FAN_ONDIR without an event type */
> > > + BUILD_BUG_ON(FANOTIFY_EVENT_TYPES & FANOTIFY_EVENT_FLAGS);
> > > + if (!(test_mask & FANOTIFY_EVENT_TYPES))
> > > + return 0;
> > > +
> > > + user_mask |= FAN_ONDIR;
> > > + }
> > > +
> > > + /*
> > > + * Unlike legacy fanotify events (open/access/close), dirent events
> > > + * for subdir entries (mkdir/rmdir) will be reported regardless if
> > > + * user requested FAN_ONDIR, but the FAN_ONDIR flag itself will only
> > > + * be reported if the user asked for it.
> > > + */
> > > if (event_mask & FS_ISDIR &&
> > > + !(event_mask & ALL_FSNOTIFY_DIRENT_EVENTS) &&
> >
> > I disagree with this. It just seems inconsistent for dirent events for
> > directories to get reported without FAN_ONDIR. I understand there's not
> > great use for not reporting directory dirent events but it's not like
> > adding FAN_ONDIR to the mark mask is that big deal for userspace. And it
> > makes the API more consistent. You could possibly remind the reader in the
> > manpage that FAN_ONDIR is required to get all dirent events.
>
> I see your point.
> I have no problem with requiring FAN_ONDIR for mkdir events.
> I believe the strongest argument should be which way is easier
> to document/understand.
>
> Matthew, if you agree that it looks easier to document Jan's proposal,
> please go a head with this and we will see how man page looks like
> before making the final decision.
Agreed.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
