4 files changed, 41 insertions, 0 deletions

diff --git a/include/linux/sunrpc/rpc_pipe_fs.h b/include/linux/sunrpc/rpc_pipe_fs.h
index 2f3382230141..c13fca34dc9c 100644
--- a/include/linux/sunrpc/rpc_pipe_fs.h
+++ b/include/linux/sunrpc/rpc_pipe_fs.h
@@ -53,6 +53,9 @@ enum {
 
 extern struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
                                       const unsigned char *dir_name);
+extern void rpc_pipefs_init_net(struct net *net);
+extern struct super_block *rpc_get_sb_net(const struct net *net);
+extern void rpc_put_sb_net(const struct net *net);
 
 extern ssize_t rpc_pipe_generic_upcall(struct file *, struct rpc_pipe_msg *,
                                        char __user *, size_t);
diff --git a/net/sunrpc/netns.h b/net/sunrpc/netns.h
index b3842529aec9..11d2f4863403 100644
--- a/net/sunrpc/netns.h
+++ b/net/sunrpc/netns.h
@@ -11,6 +11,7 @@ struct sunrpc_net {
         struct cache_detail *ip_map_cache;
 
         struct super_block *pipefs_sb;
+        struct mutex pipefs_sb_lock;
 };
 
 extern int sunrpc_net_id;
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index e5e1f357b561..f075f8817773 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -1023,6 +1023,40 @@ struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
 }
 EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);
 
+void rpc_pipefs_init_net(struct net *net)
+{
+        struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+
+        mutex_init(&sn->pipefs_sb_lock);
+}
+
+/*
+ * This call will be used for per network namespace operations calls.
+ * Note: Function will be returned with pipefs_sb_lock taken if superblock was
+ * found. This lock have to be released by rpc_put_sb_net() when all operations
+ * will be completed.
+ */
+struct super_block *rpc_get_sb_net(const struct net *net)
+{
+        struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+
+        mutex_lock(&sn->pipefs_sb_lock);
+        if (sn->pipefs_sb)
+                return sn->pipefs_sb;
+        mutex_unlock(&sn->pipefs_sb_lock);
+        return NULL;
+}
+EXPORT_SYMBOL_GPL(rpc_get_sb_net);
+
+void rpc_put_sb_net(const struct net *net)
+{
+        struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
+
+        BUG_ON(sn->pipefs_sb == NULL);
+        mutex_unlock(&sn->pipefs_sb_lock);
+}
+EXPORT_SYMBOL_GPL(rpc_put_sb_net);
+
 static int
 rpc_fill_super(struct super_block *sb, void *data, int silent)
 {
@@ -1077,7 +1111,9 @@ void rpc_kill_sb(struct super_block *sb)
         struct net *net = sb->s_fs_info;
         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 
+        mutex_lock(&sn->pipefs_sb_lock);
         sn->pipefs_sb = NULL;
+        mutex_unlock(&sn->pipefs_sb_lock);
         put_net(net);
         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
                                            RPC_PIPEFS_UMOUNT,
diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c
index 8ec9778c3f4a..7086d11589c8 100644
--- a/net/sunrpc/sunrpc_syms.c
+++ b/net/sunrpc/sunrpc_syms.c
@@ -38,6 +38,7 @@ static __net_init int sunrpc_init_net(struct net *net)
         if (err)
                 goto err_ipmap;
 
+        rpc_pipefs_init_net(net);
         return 0;
 
 err_ipmap: