[RFC PATCH 0/4 v2] Inotify limits per usernamespace

[Nikolay Borisov <kernel-6AxghH7DbtA@public.gmane.org>]

So this is the 2nd incarnation of the inotify-limits per namespace, 
following the lenghty discussions with Eric Biederman. The core of 
the series lies in patch 3, as this contains most of the code to 
implement the new semantics. The major difference is now that 
inotify limits are going to be accounted per-user/per-namespace. 

Patch 1 adds a __HASHTABLE_INITIALIZER, much in the same way as 
other kernel constructs have, so that one can use them directly 
into structure definitions. It's a self-contained patch 

Patch 2 is unchanged from the previous submissions and just 
renames some defines in various networking files, implementing
their own hashtable as this creates certain warnings due to 
hashtable.h inclusion in linux/user_namespace.h. This has already
been acked-by David Miller. 

Patch 3 is the core, it implements all the necessary changes
to allow. More information about the implementation in the patch
changelog. This has been completely changed than in the first
submission to cope with the requirements that emerged in 
discussion with Eric Biederman.

Patch 4 is plain conversion, to the new interface inotify code
structure.

The series has received moderate testing in a KVM guest, using
the stress-ng to create multiple inotify instances and test
whether the locking is correct which seems to be the case. I've
tested with 2/3 level hierarchies of namespaces. 

Nikolay Borisov (4):
  hashtable: Add __HASHTABLE_INITIALIZER
  misc: Rename the HASH_SIZE macro
  userns/inotify: Initial implementation of inotify per-userns
  inotify: Convert to using new userns infrastructure

 fs/logfs/dir.c                           |   6 +-
 fs/notify/inotify/inotify.h              |  25 ++++
 fs/notify/inotify/inotify_fsnotify.c     |  16 ++-
 fs/notify/inotify/inotify_user.c         | 240 +++++++++++++++++++++++++++++--
 include/linux/fsnotify_backend.h         |   3 +
 include/linux/hashtable.h                |   3 +
 include/linux/sched.h                    |   4 -
 include/linux/user_namespace.h           |  10 ++
 kernel/user.c                            |   5 +
 kernel/user_namespace.c                  |  22 ++-
 net/ipv6/ip6_gre.c                       |   8 +-
 net/ipv6/ip6_tunnel.c                    |  10 +-
 net/ipv6/ip6_vti.c                       |  10 +-
 net/ipv6/sit.c                           |  10 +-
 security/keys/encrypted-keys/encrypted.c |  32 ++---
 15 files changed, 345 insertions(+), 59 deletions(-)

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2.5.0