8 files changed, 46 insertions, 25 deletions
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 35e7eca4e33b..52a640128151 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -6,6 +6,7 @@
 #include <linux/rwsem.h>
 #include <linux/notifier.h>
 #include <linux/nsproxy.h>
+#include <linux/ns_common.h>
 
 /*
  * ipc namespace events
@@ -68,7 +69,7 @@ struct ipc_namespace {
 	/* user_ns which owns the ipc ns */
 	struct user_namespace *user_ns;
 
-	unsigned int	proc_inum;
+	struct ns_common ns;
 };
 
 extern struct ipc_namespace init_ipc_ns;
diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
new file mode 100644
index 000000000000..85a5c8c16be9
--- /dev/null
+++ b/include/linux/ns_common.h
@@ -0,0 +1,12 @@
+#ifndef _LINUX_NS_COMMON_H
+#define _LINUX_NS_COMMON_H
+
+struct proc_ns_operations;
+
+struct ns_common {
+	atomic_long_t stashed;
+	const struct proc_ns_operations *ops;
+	unsigned int inum;
+};
+
+#endif
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 1997ffc295a7..b9cf6c51b181 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -8,6 +8,7 @@
 #include <linux/threads.h>
 #include <linux/nsproxy.h>
 #include <linux/kref.h>
+#include <linux/ns_common.h>
 
 struct pidmap {
        atomic_t nr_free;
@@ -43,7 +44,7 @@ struct pid_namespace {
 	kgid_t pid_gid;
 	int hide_pid;
 	int reboot;	/* group exit code if this pidns was rebooted */
-	unsigned int proc_inum;
+	struct ns_common ns;
 };
 
 extern struct pid_namespace init_pid_ns;
diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
index 34a1e105bef4..42dfc615dbf8 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -4,21 +4,18 @@
 #ifndef _LINUX_PROC_NS_H
 #define _LINUX_PROC_NS_H
 
+#include <linux/ns_common.h>
+
 struct pid_namespace;
 struct nsproxy;
+struct path;
 
 struct proc_ns_operations {
 	const char *name;
 	int type;
-	void *(*get)(struct task_struct *task);
-	void (*put)(void *ns);
-	int (*install)(struct nsproxy *nsproxy, void *ns);
-	unsigned int (*inum)(void *ns);
-};
-
-struct proc_ns {
-	void *ns;
-	const struct proc_ns_operations *ns_ops;
+	struct ns_common *(*get)(struct task_struct *task);
+	void (*put)(struct ns_common *ns);
+	int (*install)(struct nsproxy *nsproxy, struct ns_common *ns);
 };
 
 extern const struct proc_ns_operations netns_operations;
@@ -43,32 +40,38 @@ enum {
 
 extern int pid_ns_prepare_proc(struct pid_namespace *ns);
 extern void pid_ns_release_proc(struct pid_namespace *ns);
-extern struct file *proc_ns_fget(int fd);
-extern struct proc_ns *get_proc_ns(struct inode *);
 extern int proc_alloc_inum(unsigned int *pino);
 extern void proc_free_inum(unsigned int inum);
-extern bool proc_ns_inode(struct inode *inode);
 
 #else /* CONFIG_PROC_FS */
 
 static inline int pid_ns_prepare_proc(struct pid_namespace *ns) { return 0; }
 static inline void pid_ns_release_proc(struct pid_namespace *ns) {}
 
-static inline struct file *proc_ns_fget(int fd)
-{
-	return ERR_PTR(-EINVAL);
-}
-
-static inline struct proc_ns *get_proc_ns(struct inode *inode) { return NULL; }
-
 static inline int proc_alloc_inum(unsigned int *inum)
 {
 	*inum = 1;
 	return 0;
 }
 static inline void proc_free_inum(unsigned int inum) {}
-static inline bool proc_ns_inode(struct inode *inode) { return false; }
 
 #endif /* CONFIG_PROC_FS */
 
+static inline int ns_alloc_inum(struct ns_common *ns)
+{
+	atomic_long_set(&ns->stashed, 0);
+	return proc_alloc_inum(&ns->inum);
+}
+
+#define ns_free_inum(ns) proc_free_inum((ns)->inum)
+
+extern struct file *proc_ns_fget(int fd);
+#define get_proc_ns(inode) ((struct ns_common *)(inode)->i_private)
+extern void *ns_get_path(struct path *path, struct task_struct *task,
+			const struct proc_ns_operations *ns_ops);
+
+extern int ns_get_name(char *buf, size_t size, struct task_struct *task,
+			const struct proc_ns_operations *ns_ops);
+extern void nsfs_init(void);
+
 #endif /* _LINUX_PROC_NS_H */
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index e95372654f09..4cf06c140e21 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -3,6 +3,7 @@
 
 #include <linux/kref.h>
 #include <linux/nsproxy.h>
+#include <linux/ns_common.h>
 #include <linux/sched.h>
 #include <linux/err.h>
 
@@ -26,7 +27,7 @@ struct user_namespace {
 	int			level;
 	kuid_t			owner;
 	kgid_t			group;
-	unsigned int		proc_inum;
+	struct ns_common	ns;
 
 	/* Register of per-UID persistent keyrings for this namespace */
 #ifdef CONFIG_PERSISTENT_KEYRINGS
diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 239e27733d6c..5093f58ae192 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -5,6 +5,7 @@
 #include <linux/sched.h>
 #include <linux/kref.h>
 #include <linux/nsproxy.h>
+#include <linux/ns_common.h>
 #include <linux/err.h>
 #include <uapi/linux/utsname.h>
 
@@ -23,7 +24,7 @@ struct uts_namespace {
 	struct kref kref;
 	struct new_utsname name;
 	struct user_namespace *user_ns;
-	unsigned int proc_inum;
+	struct ns_common ns;
 };
 extern struct uts_namespace init_uts_ns;
 
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index e0d64667a4b3..2e8756b8c775 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -26,6 +26,7 @@
 #endif
 #include <net/netns/nftables.h>
 #include <net/netns/xfrm.h>
+#include <linux/ns_common.h>
 
 struct user_namespace;
 struct proc_dir_entry;
@@ -60,7 +61,7 @@ struct net {
 
 	struct user_namespace   *user_ns;	/* Owning user namespace */
 
-	unsigned int		proc_inum;
+	struct ns_common	ns;
 
 	struct proc_dir_entry 	*proc_net;
 	struct proc_dir_entry 	*proc_net_stat;
diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index 77c60311a6c6..7d664ea85ebd 100644
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -72,5 +72,6 @@
 #define MTD_INODE_FS_MAGIC      0x11307854
 #define ANON_INODE_FS_MAGIC	0x09041934
 #define BTRFS_TEST_MAGIC	0x73727279
+#define NSFS_MAGIC		0x6e736673
 
 #endif /* __LINUX_MAGIC_H__ */