[PATCH RFC v20 05/10] NFSD: Update find_clp_in_name_tree() to handle courtesy client

[Dai Ngo <dai.ngo@xxxxxxxxxx>]

Update find_clp_in_name_tree to check and expire courtesy client.

Update find_confirmed_client_by_name to discard the courtesy
client by setting CLIENT_EXPIRED.

Update nfsd4_setclientid to expire client with CLIENT_EXPIRED
state to prevent multiple confirmed clients with the same name
on the conf_name_tree.

Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
---
 fs/nfsd/nfs4state.c | 25 ++++++++++++++++++++++---
 fs/nfsd/state.h     | 28 ++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index fe8969ba94b3..d14cea763511 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2893,8 +2893,11 @@ find_clp_in_name_tree(struct xdr_netobj *name, struct rb_root *root)
 			node = node->rb_left;
 		else if (cmp < 0)
 			node = node->rb_right;
-		else
+		else {
+			if (nfsd4_courtesy_clnt_expired(clp))
+				return NULL;
 			return clp;
+		}
 	}
 	return NULL;
 }
@@ -2973,8 +2976,13 @@ static bool clp_used_exchangeid(struct nfs4_client *clp)
 static struct nfs4_client *
 find_confirmed_client_by_name(struct xdr_netobj *name, struct nfsd_net *nn)
 {
+	struct nfs4_client *clp;
+
 	lockdep_assert_held(&nn->client_lock);
-	return find_clp_in_name_tree(name, &nn->conf_name_tree);
+	clp = find_clp_in_name_tree(name, &nn->conf_name_tree);
+	if (clp && nfsd4_discard_reconnect_clnt(clp))
+		clp = NULL;
+	return clp;
 }
 
 static struct nfs4_client *
@@ -4091,12 +4099,19 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	struct nfs4_client	*unconf = NULL;
 	__be32 			status;
 	struct nfsd_net		*nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
+	struct nfs4_client	*cclient = NULL;
 
 	new = create_client(clname, rqstp, &clverifier);
 	if (new == NULL)
 		return nfserr_jukebox;
 	spin_lock(&nn->client_lock);
-	conf = find_confirmed_client_by_name(&clname, nn);
+	/* find confirmed client by name */
+	conf = find_clp_in_name_tree(&clname, &nn->conf_name_tree);
+	if (conf && conf->cl_cs_client_state == NFSD4_CLIENT_RECONNECTED) {
+		cclient = conf;
+		conf = NULL;
+	}
+
 	if (conf && client_has_state(conf)) {
 		status = nfserr_clid_inuse;
 		if (clp_used_exchangeid(conf))
@@ -4127,7 +4142,11 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	new = NULL;
 	status = nfs_ok;
 out:
+	if (cclient)
+		unhash_client_locked(cclient);
 	spin_unlock(&nn->client_lock);
+	if (cclient)
+		expire_client(cclient);
 	if (new)
 		free_client(new);
 	if (unconf) {
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 8b81493ee48a..16167f223353 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -735,6 +735,7 @@ extern void nfsd4_client_record_remove(struct nfs4_client *clp);
 extern int nfsd4_client_record_check(struct nfs4_client *clp);
 extern void nfsd4_record_grace_done(struct nfsd_net *nn);
 
+/* courteous server */
 static inline bool
 nfsd4_expire_courtesy_clnt(struct nfs4_client *clp)
 {
@@ -749,4 +750,31 @@ nfsd4_expire_courtesy_clnt(struct nfs4_client *clp)
 	return rc;
 }
 
+static inline bool
+nfsd4_discard_reconnect_clnt(struct nfs4_client *clp)
+{
+	bool ret = false;
+
+	spin_lock(&clp->cl_cs_lock);
+	if (clp->cl_cs_client_state == NFSD4_CLIENT_RECONNECTED) {
+		clp->cl_cs_client_state = NFSD4_CLIENT_EXPIRED;
+		ret = true;
+	}
+	spin_unlock(&clp->cl_cs_lock);
+	return ret;
+}
+
+static inline bool
+nfsd4_courtesy_clnt_expired(struct nfs4_client *clp)
+{
+	bool rc = false;
+
+	spin_lock(&clp->cl_cs_lock);
+	if (clp->cl_cs_client_state == NFSD4_CLIENT_EXPIRED)
+		rc = true;
+	if (clp->cl_cs_client_state == NFSD4_CLIENT_COURTESY)
+		clp->cl_cs_client_state = NFSD4_CLIENT_RECONNECTED;
+	spin_unlock(&clp->cl_cs_lock);
+	return rc;
+}
 #endif   /* NFSD4_STATE_H */
-- 
2.9.5