1 files changed, 79 insertions, 4 deletions

diff --git a/fs/proc/root.c b/fs/proc/root.c
index cf3046638b09..ec9cb3b6c93b 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -18,32 +18,90 @@
 #include <linux/bitops.h>
 #include <linux/smp_lock.h>
 #include <linux/mount.h>
+#include <linux/pid_namespace.h>
 
 #include "internal.h"
 
 struct proc_dir_entry *proc_bus, *proc_root_fs, *proc_root_driver;
 
+static int proc_test_super(struct super_block *sb, void *data)
+{
+        return sb->s_fs_info == data;
+}
+
+static int proc_set_super(struct super_block *sb, void *data)
+{
+        struct pid_namespace *ns;
+
+        ns = (struct pid_namespace *)data;
+        sb->s_fs_info = get_pid_ns(ns);
+        return set_anon_super(sb, NULL);
+}
+
 static int proc_get_sb(struct file_system_type *fs_type,
         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 {
+        int err;
+        struct super_block *sb;
+        struct pid_namespace *ns;
+        struct proc_inode *ei;
+
         if (proc_mnt) {
                 /* Seed the root directory with a pid so it doesn't need
                  * to be special in base.c.  I would do this earlier but
                  * the only task alive when /proc is mounted the first time
                  * is the init_task and it doesn't have any pids.
                  */
-                struct proc_inode *ei;
                 ei = PROC_I(proc_mnt->mnt_sb->s_root->d_inode);
                 if (!ei->pid)
                         ei->pid = find_get_pid(1);
         }
-        return get_sb_single(fs_type, flags, data, proc_fill_super, mnt);
+
+        if (flags & MS_KERNMOUNT)
+                ns = (struct pid_namespace *)data;
+        else
+                ns = current->nsproxy->pid_ns;
+
+        sb = sget(fs_type, proc_test_super, proc_set_super, ns);
+        if (IS_ERR(sb))
+                return PTR_ERR(sb);
+
+        if (!sb->s_root) {
+                sb->s_flags = flags;
+                err = proc_fill_super(sb);
+                if (err) {
+                        up_write(&sb->s_umount);
+                        deactivate_super(sb);
+                        return err;
+                }
+
+                ei = PROC_I(sb->s_root->d_inode);
+                if (!ei->pid) {
+                        rcu_read_lock();
+                        ei->pid = get_pid(find_pid_ns(1, ns));
+                        rcu_read_unlock();
+                }
+
+                sb->s_flags |= MS_ACTIVE;
+                ns->proc_mnt = mnt;
+        }
+
+        return simple_set_mnt(mnt, sb);
+}
+
+static void proc_kill_sb(struct super_block *sb)
+{
+        struct pid_namespace *ns;
+
+        ns = (struct pid_namespace *)sb->s_fs_info;
+        kill_anon_super(sb);
+        put_pid_ns(ns);
 }
 
 static struct file_system_type proc_fs_type = {
         .name           = "proc",
         .get_sb         = proc_get_sb,
-        .kill_sb        = kill_anon_super,
+        .kill_sb        = proc_kill_sb,
 };
 
 void __init proc_root_init(void)
@@ -54,12 +112,13 @@ void __init proc_root_init(void)
         err = register_filesystem(&proc_fs_type);
         if (err)
                 return;
-        proc_mnt = kern_mount(&proc_fs_type);
+        proc_mnt = kern_mount_data(&proc_fs_type, &init_pid_ns);
         err = PTR_ERR(proc_mnt);
         if (IS_ERR(proc_mnt)) {
                 unregister_filesystem(&proc_fs_type);
                 return;
         }
+
         proc_misc_init();
 
         proc_net_init();
@@ -153,6 +212,22 @@ struct proc_dir_entry proc_root = {
         .parent         = &proc_root,
 };
 
+int pid_ns_prepare_proc(struct pid_namespace *ns)
+{
+        struct vfsmount *mnt;
+
+        mnt = kern_mount_data(&proc_fs_type, ns);
+        if (IS_ERR(mnt))
+                return PTR_ERR(mnt);
+
+        return 0;
+}
+
+void pid_ns_release_proc(struct pid_namespace *ns)
+{
+        mntput(ns->proc_mnt);
+}
+
 EXPORT_SYMBOL(proc_symlink);
 EXPORT_SYMBOL(proc_mkdir);
 EXPORT_SYMBOL(create_proc_entry);