[PATCH v4 0/3] add support for CB_RECALL_ANY and the delegation shrinker

[Dai Ngo <dai.ngo@oracle.com>]

This patch series adds:

    . XDR encode and decode function for CB_RECALL_ANY op.

    . the delegation shrinker that sends the advisory CB_RECALL_ANY 
      to the clients to release unused delegations.
      There is only one nfsd4_callback added for each nfs4_cleint.
      Access to it must be serialized via the client flag
      NFSD4_CLIENT_CB_RECALL_ANY.

v2:
    . modify deleg_reaper to check and send CB_RECALL_ANY to client
      only once per 5 secs.
v3:
    . modify nfsd4_cb_recall_any_release to use nn->client_lock to
      protect cl_recall_any_busy and call put_client_renew_locked
      to decrement cl_rpc_users.

v4:
    . move changes in nfs4state.c from patch (1/2) to patch(2/2).
    . use xdr_stream_encode_u32 and xdr_stream_encode_uint32_array
      to encode CB_RECALL_ANY arguments.
    . add struct nfsd4_cb_recall_any with embedded nfs4_callback
      and params for CB_RECALL_ANY op.
    . replace cl_recall_any_busy boolean with client flag
      NFSD4_CLIENT_CB_RECALL_ANY 
    . add tracepoints for CB_RECALL_ANY
---

Dai Ngo (3):
     NFSD: add support for sending CB_RECALL_ANY
     NFSD: add delegation shrinker to react to low memory condition
     NFSD: add CB_RECALL_ANY tracepoints

 fs/nfsd/netns.h        |   3 ++
 fs/nfsd/nfs4callback.c |  62 +++++++++++++++++++++++
 fs/nfsd/nfs4state.c    | 117 +++++++++++++++++++++++++++++++++++++++++++-
 fs/nfsd/state.h        |   9 ++++
 fs/nfsd/trace.h        |  53 ++++++++++++++++++++
 fs/nfsd/xdr4.h         |   5 ++
 fs/nfsd/xdr4cb.h       |   6 +++
 7 files changed, 254 insertions(+), 1 deletion(-)