[PATCH 3/3] nfsd: add tracepoint in mark_client_expired_locked

[Jeff Layton <jlayton@kernel.org>]

Show client info alongside the number of cl_rpc_users. If that's
elevated, then we can infer that this function returned nfserr_jukebox.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfsd/nfs4state.c |  6 +++++-
 fs/nfsd/trace.h     | 24 ++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 5891bc3e2b0b..2b5dadeed8c9 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2352,7 +2352,11 @@ unhash_client(struct nfs4_client *clp)
 
 static __be32 mark_client_expired_locked(struct nfs4_client *clp)
 {
-	if (atomic_read(&clp->cl_rpc_users))
+	int users = atomic_read(&clp->cl_rpc_users);
+
+	trace_mark_client_expired_locked(clp, users);
+
+	if (users)
 		return nfserr_jukebox;
 	unhash_client_locked(clp);
 	return nfs_ok;
diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index ec00ca7ecfc8..b50d6a71c7d9 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -1576,6 +1576,30 @@ TRACE_EVENT(check_slot_seqid,
 	)
 );
 
+TRACE_EVENT(mark_client_expired_locked,
+	TP_PROTO(
+		const struct nfs4_client *clp,
+		int cl_rpc_users
+	),
+	TP_ARGS(clp, cl_rpc_users),
+	TP_STRUCT__entry(
+		__field(int, cl_rpc_users)
+		__field(u32, cl_boot)
+		__field(u32, cl_id)
+		__sockaddr(addr, clp->cl_cb_conn.cb_addrlen)
+	),
+	TP_fast_assign(
+		__entry->cl_rpc_users = cl_rpc_users;
+		__entry->cl_boot = clp->cl_clientid.cl_boot;
+		__entry->cl_id = clp->cl_clientid.cl_id;
+		__assign_sockaddr(addr, &clp->cl_cb_conn.cb_addr,
+				  clp->cl_cb_conn.cb_addrlen)
+	),
+	TP_printk("addr=%pISpc client %08x:%08x cl_rpc_users=%d",
+		__get_sockaddr(addr), __entry->cl_boot, __entry->cl_id,
+		__entry->cl_rpc_users)
+);
+
 TRACE_EVENT(nfsd_cb_free_slot,
 	TP_PROTO(
 		const struct rpc_task *task,

-- 
2.44.0