Messages in this thread Patch in this message | | | Date | Fri, 07 May 2010 11:24:48 +0200 | From | Anders Blomdell <> | Subject | fanotify issues in 2.6.34-rc6-next-20100506 |
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I have started to have a look at the fanotify system, based on information gleaned from:
[1] http://people.redhat.com/~eparis/fanotify/ [2] http://lwn.net/Articles/360955/
Unfortunately there seems to be some bug in the current implemenation, since running a patched version of the fanotify.c application found in [1]
--- fanotify.c.orig 2010-03-27 05:26:27.000000000 +0100 +++ fanotify.c 2010-05-07 10:56:38.000000000 +0200 @@ -125,7 +125,7 @@ fan_mask |= FAN_ALL_PERM_EVENTS;
// fanotify_init(flags, event_f_flags, priority) - fan_fd = fanotify_init(0, O_RDONLY | O_LARGEFILE, 0); + fan_fd = fanotify_init(0, 0, 0); if (fan_fd < 0) goto fail;
seems to lose/corrupt events. For instance running 'fanotify -c /dir/to/watch' and then running the command 'cd /dir/to/watch ; touch a b c d e f g h i j k l' might generate (results are more or less random): /dir/to/watch/a: pid=18584 open /dir/to/watch/a: pid=18584 close(writable) /dir/to/watch/b: pid=18584 open # 2 open events for b /dir/to/watch/b: pid=18584 open close(writable) # /dir/to/watch/d: pid=18584 open # events for c missing /dir/to/watch/d: pid=18584 open close(writable) # 2 open events for d /dir/to/watch/f: pid=18584 open close(writable) # events for e missing /dir/to/watch/g: pid=18584 open close(writable) /dir/to/watch/h: pid=18584 open close(writable) /dir/to/watch/i: pid=18584 open close(writable) /dir/to/watch/j: pid=18584 open /dir/to/watch/j: pid=18584 close(writable) /dir/to/watch/k: pid=18584 open /dir/to/watch/k: pid=18584 open close(writable) # 2 open events for k /dir/to/watch/l: pid=18584 close(writable) # no open event for l
A similar program using inotify gets all events correctly.
I have also problems with the fact that the following sequence dosn't leave a trace in the fanotify events:
mkdir /dir/not/watched touch /dir/not/watched/z ln /dir/not/watched/z /dir/to/watch/z rm /dir/not/watched/z rmdir /dir/not/watched)
What is the rationale for not reporting link/unlink events via fanotify?
Best regards
Anders Blomdell
-- Anders Blomdell Email: anders.blomdell@control.lth.se Department of Automatic Control Lund University Phone: +46 46 222 4625 P.O. Box 118 Fax: +46 46 138118 SE-221 00 Lund, Sweden
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