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From:   Dai Ngo <dai.ngo@oracle.com>
To:     chuck.lever@oracle.com
Cc:     linux-nfs@vger.kernel.org
Subject: [PATCH 1/2] NFSD: keep track of the number of courtesy clients in the system
Date:   Fri, 26 Aug 2022 16:01:25 -0700
Message-Id: <1661554886-26025-2-git-send-email-dai.ngo@oracle.com>
In-Reply-To: <1661554886-26025-1-git-send-email-dai.ngo@oracle.com>
References: <1661554886-26025-1-git-send-email-dai.ngo@oracle.com>
Precedence: bulk

Add counter nfs4_courtesy_client_count to nfsd_net to keep track
of the number of courtesy clients in the system.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/netns.h     |  2 ++
 fs/nfsd/nfs4state.c | 20 +++++++++++++++-----
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index ffe17743cc74..2695dff1378a 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -192,6 +192,8 @@ struct nfsd_net {
 
 	atomic_t		nfs4_client_count;
 	int			nfs4_max_clients;
+
+	atomic_t		nfsd_courtesy_client_count;
 };
 
 /* Simple check to find out if a given net was properly initialized */
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index c5d199d7e6b4..3d8d7ebb5b91 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -169,7 +169,8 @@ static __be32 get_client_locked(struct nfs4_client *clp)
 	if (is_client_expired(clp))
 		return nfserr_expired;
 	atomic_inc(&clp->cl_rpc_users);
-	clp->cl_state = NFSD4_ACTIVE;
+	if (xchg(&clp->cl_state, NFSD4_ACTIVE) != NFSD4_ACTIVE)
+		atomic_add_unless(&nn->nfsd_courtesy_client_count, -1, 0);
 	return nfs_ok;
 }
 
@@ -190,7 +191,8 @@ renew_client_locked(struct nfs4_client *clp)
 
 	list_move_tail(&clp->cl_lru, &nn->client_lru);
 	clp->cl_time = ktime_get_boottime_seconds();
-	clp->cl_state = NFSD4_ACTIVE;
+	if (xchg(&clp->cl_state, NFSD4_ACTIVE) != NFSD4_ACTIVE)
+		atomic_add_unless(&nn->nfsd_courtesy_client_count, -1, 0);
 }
 
 static void put_client_renew_locked(struct nfs4_client *clp)
@@ -2233,6 +2235,8 @@ __destroy_client(struct nfs4_client *clp)
 	if (clp->cl_cb_conn.cb_xprt)
 		svc_xprt_put(clp->cl_cb_conn.cb_xprt);
 	atomic_add_unless(&nn->nfs4_client_count, -1, 0);
+	if (clp->cl_state != NFSD4_ACTIVE)
+		atomic_add_unless(&nn->nfsd_courtesy_client_count, -1, 0);
 	free_client(clp);
 	wake_up_all(&expiry_wq);
 }
@@ -4356,6 +4360,8 @@ void nfsd4_init_leases_net(struct nfsd_net *nn)
 	max_clients = (u64)si.totalram * si.mem_unit / (1024 * 1024 * 1024);
 	max_clients *= NFS4_CLIENTS_PER_GB;
 	nn->nfs4_max_clients = max_t(int, max_clients, NFS4_CLIENTS_PER_GB);
+
+	atomic_set(&nn->nfsd_courtesy_client_count, 0);
 }
 
 static void init_nfs4_replay(struct nfs4_replay *rp)
@@ -5864,7 +5870,7 @@ static void
 nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist,
 				struct laundry_time *lt)
 {
-	unsigned int maxreap, reapcnt = 0;
+	unsigned int oldstate, maxreap, reapcnt = 0;
 	struct list_head *pos, *next;
 	struct nfs4_client *clp;
 
@@ -5878,8 +5884,12 @@ nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist,
 			goto exp_client;
 		if (!state_expired(lt, clp->cl_time))
 			break;
-		if (!atomic_read(&clp->cl_rpc_users))
-			clp->cl_state = NFSD4_COURTESY;
+		oldstate = NFSD4_ACTIVE;
+		if (!atomic_read(&clp->cl_rpc_users)) {
+			oldstate = xchg(&clp->cl_state, NFSD4_COURTESY);
+			if (oldstate == NFSD4_ACTIVE)
+				atomic_inc(&nn->nfsd_courtesy_client_count);
+		}
 		if (!client_has_state(clp))
 			goto exp_client;
 		if (!nfs4_anylock_blockers(clp))
-- 
2.9.5