nfsd4: mark_client_expired

Mark the client as expired under the client_lock so it won't be renewed
when an nfsv4.1 session is done, after it was explicitly expired
during processing of the compound.

Do not renew a client mark as expired (in particular, it is not
on the lru list anymore)

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index e439a88..98aa7e8 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -632,6 +632,14 @@
 static inline void
 renew_client_locked(struct nfs4_client *clp)
 {
+	if (is_client_expired(clp)) {
+		dprintk("%s: client (clientid %08x/%08x) already expired\n",
+			__func__,
+			clp->cl_clientid.cl_boot,
+			clp->cl_clientid.cl_id);
+		return;
+	}
+
 	/*
 	* Move client to the end to the LRU list.
 	*/
@@ -697,6 +705,7 @@
 static inline void
 unhash_client_locked(struct nfs4_client *clp)
 {
+	mark_client_expired(clp);
 	list_del(&clp->cl_lru);
 	while (!list_empty(&clp->cl_sessions)) {
 		struct nfsd4_session  *ses;
@@ -836,6 +845,7 @@
 	INIT_LIST_HEAD(&clp->cl_delegations);
 	INIT_LIST_HEAD(&clp->cl_sessions);
 	INIT_LIST_HEAD(&clp->cl_lru);
+	clp->cl_time = get_seconds();
 	clear_bit(0, &clp->cl_cb_slot_busy);
 	rpc_init_wait_queue(&clp->cl_cb_waitq, "Backchannel slot table");
 	copy_verf(clp, verf);
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index ee42a0b..cfd743e 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -166,7 +166,7 @@
 	struct list_head	se_hash;	/* hash by sessionid */
 	struct list_head	se_perclnt;
 	u32			se_flags;
-	struct nfs4_client	*se_client;	/* for expire_client */
+	struct nfs4_client	*se_client;
 	struct nfs4_sessionid	se_sessionid;
 	struct nfsd4_channel_attrs se_fchannel;
 	struct nfsd4_channel_attrs se_bchannel;
@@ -244,6 +244,18 @@
 						/* wait here for slots */
 };
 
+static inline void
+mark_client_expired(struct nfs4_client *clp)
+{
+	clp->cl_time = 0;
+}
+
+static inline bool
+is_client_expired(struct nfs4_client *clp)
+{
+	return clp->cl_time == 0;
+}
+
 /* struct nfs4_client_reset
  * one per old client. Populates reset_str_hashtbl. Filled from conf_id_hashtbl
  * upon lease reset, or from upcall to state_daemon (to read in state