NFSv4.1: add tracepoint to trunked nfs4_exchange_id calls

Add a tracepoint to track when the client sends EXCHANGE_ID to test
a new transport for session trunking.

nfs4_detect_session_trunking() tests for trunking and returns
EINVAL if trunking can't be done, add EINVAL mapping to
show_nfs4_status() in tracepoints.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSD: Add callback operation lifetime trace points

Help observe the flow of callback operations.

bc_shutdown() records exactly when the backchannel RPC client is
destroyed and cl_cb_client is replaced with NULL.

Examples include:

nfsd-955 [004] 650.013997: nfsd_cb_queue: addr=192.168.122.6:0 client 65b3c5b8:f541f749 cb=0xffff8881134b02f8 (first try)
kworker/u21:4-497 [004] 650.014050: nfsd_cb_seq_status: task:00000001@00000001 sessionid=65b3c5b8:f541f749:00000001:00000000 tk_status=-107 seq_status=1
kworker/u21:4-497 [004] 650.014051: nfsd_cb_restart: addr=192.168.122.6:0 client 65b3c5b8:f541f749 cb=0xffff88810e39f400 (first try)
kworker/u21:4-497 [004] 650.014066: nfsd_cb_queue: addr=192.168.122.6:0 client 65b3c5b8:f541f749 cb=0xffff88810e39f400 (need restart)


kworker/u16:0-10 [006] 650.065750: nfsd_cb_start: addr=192.168.122.6:0 client 65b3c5b8:f541f749 state=UNKNOWN
kworker/u16:0-10 [006] 650.065752: nfsd_cb_bc_update: addr=192.168.122.6:0 client 65b3c5b8:f541f749 cb=0xffff8881134b02f8 (first try)
kworker/u16:0-10 [006] 650.065754: nfsd_cb_bc_shutdown: addr=192.168.122.6:0 client 65b3c5b8:f541f749 cb=0xffff8881134b02f8 (first try)
kworker/u16:0-10 [006] 650.065810: nfsd_cb_new_state: addr=192.168.122.6:0 client 65b3c5b8:f541f749 state=DOWN

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

NFSD: add CB_RECALL_ANY tracepoints

Add tracepoints to trace start and end of CB_RECALL_ANY operation.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
[ cel: added show_rca_mask() macro ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

trace: Relocate event helper files

Steven Rostedt says:
> The include/trace/events/ directory should only hold files that
> are to create events, not headers that hold helper functions.
>
> Can you please move them out of include/trace/events/ as that
> directory is "special" in the creation of events.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Leon Romanovsky <leonro@nvidia.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com>