[RFC][PATCH 0/2] fsnotify: reduce coupling of permission and non permission events

[Amir Goldstein <amir73il@gmail.com>]

The issue reported by Miklos Szeredi was processes blocking when trying
to close an inotify file descriptor, while another fanotify listener is
failing to handle permission events.

Miklos included a test program with the report.
His test program with some modifications is available on my github:
https://github.com/amir73il/fsnotify-utils/blob/master/fanotify_bug.c

Ideally, we would want that destruction of a group would only block
if an event handled by this group is in progress, but this is not easy
to achieve. Instead, we make sure that destrurction of a group would
only block if an event handled by a group of similar class (priority)
is in progress.

Amir Goldstein (2):
  fsnotify: separate fsnotify_mark_srcu for groups with permission
    events
  fsnotify: handle permission events without holding
    fsnotify_mark_srcu[0]

 fs/notify/fanotify/fanotify.c | 15 ++++++---
 fs/notify/fsnotify.c          | 57 ++++++++++++++++++++++++++++----
 fs/notify/fsnotify.h          | 17 ++++++++--
 fs/notify/group.c             |  2 +-
 fs/notify/mark.c              | 77 ++++++++++++++++++++++++++++++++-----------
 5 files changed, 134 insertions(+), 34 deletions(-)

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2.7.4