NFSD: Trace delegation revocations
Delegation revocation is an exceptional event that is not otherwise
visible externally (eg, no network traffic is emitted). Generate a
trace record when it occurs so that revocation can be observed or
other activity can be triggered. Example:
nfsd-1104 [005] 1912.002544: nfsd_stid_revoke: client
633c9343:
4e82788d stateid
00000003:
00000001 ref=2 type=DELEG
Trace infrastructure is provided for subsequent additional tracing
related to nfs4_stid activity.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>