[PATCH 4/4] NFS: make nfs_client_lock per net ns

[Stanislav Kinsbursky <skinsbursky@parallels.com>]

This patch makes nfs_clients_lock allocated per network namespace. All items it
protects are already network namespace aware.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>

---
 fs/nfs/client.c   |   51 +++++++++++++++++++++++++++++----------------------
 fs/nfs/idmap.c    |    4 ++--
 fs/nfs/internal.h |    3 ---
 fs/nfs/netns.h    |    1 +
 4 files changed, 32 insertions(+), 27 deletions(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index f51b279..9e11d29 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -55,7 +55,6 @@
 
 #define NFSDBG_FACILITY		NFSDBG_CLIENT
 
-DEFINE_SPINLOCK(nfs_client_lock);
 static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);
 #ifdef CONFIG_NFS_V4
 
@@ -73,9 +72,9 @@ static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
 retry:
 	if (!idr_pre_get(&nn->cb_ident_idr, GFP_KERNEL))
 		return -ENOMEM;
-	spin_lock(&nfs_client_lock);
+	spin_lock(&nn->nfs_client_lock);
 	ret = idr_get_new(&nn->cb_ident_idr, clp, &clp->cl_cb_ident);
-	spin_unlock(&nfs_client_lock);
+	spin_unlock(&nn->nfs_client_lock);
 	if (ret == -EAGAIN)
 		goto retry;
 	return ret;
@@ -313,15 +312,18 @@ static void nfs_free_client(struct nfs_client *clp)
  */
 void nfs_put_client(struct nfs_client *clp)
 {
+	struct nfs_net *nn;
+
 	if (!clp)
 		return;
 
 	dprintk("--> nfs_put_client({%d})\n", atomic_read(&clp->cl_count));
+	nn = net_generic(clp->net, nfs_net_id);
 
-	if (atomic_dec_and_lock(&clp->cl_count, &nfs_client_lock)) {
+	if (atomic_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
 		list_del(&clp->cl_share_link);
 		nfs_cb_idr_remove_locked(clp);
-		spin_unlock(&nfs_client_lock);
+		spin_unlock(&nn->nfs_client_lock);
 
 		BUG_ON(!list_empty(&clp->cl_superblocks));
 
@@ -516,7 +518,7 @@ nfs_get_client(const struct nfs_client_initdata *cl_init,
 
 	/* see if the client already exists */
 	do {
-		spin_lock(&nfs_client_lock);
+		spin_lock(&nn->nfs_client_lock);
 
 		clp = nfs_match_client(cl_init);
 		if (clp)
@@ -524,7 +526,7 @@ nfs_get_client(const struct nfs_client_initdata *cl_init,
 		if (new)
 			goto install_client;
 
-		spin_unlock(&nfs_client_lock);
+		spin_unlock(&nn->nfs_client_lock);
 
 		new = nfs_alloc_client(cl_init);
 	} while (!IS_ERR(new));
@@ -536,7 +538,7 @@ nfs_get_client(const struct nfs_client_initdata *cl_init,
 install_client:
 	clp = new;
 	list_add(&clp->cl_share_link, &nn->nfs_client_list);
-	spin_unlock(&nfs_client_lock);
+	spin_unlock(&nn->nfs_client_lock);
 
 	error = cl_init->rpc_ops->init_client(clp, timeparms, ip_addr,
 					      authflavour, noresvport);
@@ -551,7 +553,7 @@ install_client:
 	 * - make sure it's ready before returning
 	 */
 found_client:
-	spin_unlock(&nfs_client_lock);
+	spin_unlock(&nn->nfs_client_lock);
 
 	if (new)
 		nfs_free_client(new);
@@ -1041,24 +1043,25 @@ static void nfs_server_insert_lists(struct nfs_server *server)
 	struct nfs_client *clp = server->nfs_client;
 	struct nfs_net *nn = net_generic(clp->net, nfs_net_id);
 
-	spin_lock(&nfs_client_lock);
+	spin_lock(&nn->nfs_client_lock);
 	list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
 	list_add_tail(&server->master_link, &nn->nfs_volume_list);
 	clear_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
-	spin_unlock(&nfs_client_lock);
+	spin_unlock(&nn->nfs_client_lock);
 
 }
 
 static void nfs_server_remove_lists(struct nfs_server *server)
 {
 	struct nfs_client *clp = server->nfs_client;
+	struct nfs_net *nn = net_generic(clp->net, nfs_net_id);
 
-	spin_lock(&nfs_client_lock);
+	spin_lock(&nn->nfs_client_lock);
 	list_del_rcu(&server->client_link);
 	if (clp && list_empty(&clp->cl_superblocks))
 		set_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state);
 	list_del(&server->master_link);
-	spin_unlock(&nfs_client_lock);
+	spin_unlock(&nn->nfs_client_lock);
 
 	synchronize_rcu();
 }
@@ -1212,11 +1215,11 @@ nfs4_find_client_ident(struct net *net, int cb_ident)
 	struct nfs_client *clp;
 	struct nfs_net *nn = net_generic(net, nfs_net_id);
 
-	spin_lock(&nfs_client_lock);
+	spin_lock(&nn->nfs_client_lock);
 	clp = idr_find(&nn->cb_ident_idr, cb_ident);
 	if (clp)
 		atomic_inc(&clp->cl_count);
-	spin_unlock(&nfs_client_lock);
+	spin_unlock(&nn->nfs_client_lock);
 	return clp;
 }
 
@@ -1235,7 +1238,7 @@ nfs4_find_client_sessionid(const struct sockaddr *addr,
 	struct nfs_client *clp;
 	struct nfs_net *nn = net_generic(&init_net, nfs_net_id);
 
-	spin_lock(&nfs_client_lock);
+	spin_lock(&nn->nfs_client_lock);
 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
 		if (nfs4_cb_match_client(addr, clp, 1) == false)
 			continue;
@@ -1249,10 +1252,10 @@ nfs4_find_client_sessionid(const struct sockaddr *addr,
 			continue;
 
 		atomic_inc(&clp->cl_count);
-		spin_unlock(&nfs_client_lock);
+		spin_unlock(&nn->nfs_client_lock);
 		return clp;
 	}
-	spin_unlock(&nfs_client_lock);
+	spin_unlock(&nn->nfs_client_lock);
 	return NULL;
 }
 
@@ -1849,7 +1852,7 @@ static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
 	struct nfs_net *nn = net_generic(m->private, nfs_net_id);
 
 	/* lock the list against modification */
-	spin_lock(&nfs_client_lock);
+	spin_lock(&nn->nfs_client_lock);
 	return seq_list_start_head(&nn->nfs_client_list, *_pos);
 }
 
@@ -1868,7 +1871,9 @@ static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
  */
 static void nfs_server_list_stop(struct seq_file *p, void *v)
 {
-	spin_unlock(&nfs_client_lock);
+	struct nfs_net *nn = net_generic(p->private, nfs_net_id);
+
+	spin_unlock(&nn->nfs_client_lock);
 }
 
 /*
@@ -1930,7 +1935,7 @@ static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
 	struct nfs_net *nn = net_generic(m->private, nfs_net_id);
 
 	/* lock the list against modification */
-	spin_lock(&nfs_client_lock);
+	spin_lock(&nn->nfs_client_lock);
 	return seq_list_start_head(&nn->nfs_volume_list, *_pos);
 }
 
@@ -1949,7 +1954,9 @@ static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
  */
 static void nfs_volume_list_stop(struct seq_file *p, void *v)
 {
-	spin_unlock(&nfs_client_lock);
+	struct nfs_net *nn = net_generic(p->private, nfs_net_id);
+
+	spin_unlock(&nn->nfs_client_lock);
 }
 
 /*
diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index 92deaf8..aed3d2e 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -575,7 +575,7 @@ static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 	struct nfs_client *clp;
 	int error = 0;
 
-	spin_lock(&nfs_client_lock);
+	spin_lock(&nn->nfs_client_lock);
 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
 		if (clp->rpc_ops != &nfs_v4_clientops)
 			continue;
@@ -583,7 +583,7 @@ static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 		if (error)
 			break;
 	}
-	spin_unlock(&nfs_client_lock);
+	spin_unlock(&nn->nfs_client_lock);
 	return error;
 }
 
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 958fff2..b38b733 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -182,9 +182,6 @@ static inline void nfs_fs_proc_exit(void)
 {
 }
 #endif
-#ifdef CONFIG_NFS_V4
-extern spinlock_t nfs_client_lock;
-#endif
 
 /* nfs4namespace.c */
 #ifdef CONFIG_NFS_V4
diff --git a/fs/nfs/netns.h b/fs/nfs/netns.h
index 547cc95..7baad89 100644
--- a/fs/nfs/netns.h
+++ b/fs/nfs/netns.h
@@ -12,6 +12,7 @@ struct nfs_net {
 #ifdef CONFIG_NFS_V4
 	struct idr cb_ident_idr; /* Protected by nfs_client_lock */
 #endif
+	spinlock_t nfs_client_lock;
 };
 
 extern int nfs_net_id;