9 files changed, 55 insertions, 39 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 66d921e14fee..55442a6cf221 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -133,7 +133,7 @@ struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
 
 static inline int check_mnt(struct vfsmount *mnt)
 {
-        return mnt->mnt_namespace == current->namespace;
+        return mnt->mnt_namespace == current->nsproxy->namespace;
 }
 
 static void touch_namespace(struct namespace *ns)
@@ -830,7 +830,7 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt,
         if (parent_nd) {
                 detach_mnt(source_mnt, parent_nd);
                 attach_mnt(source_mnt, nd);
-                touch_namespace(current->namespace);
+                touch_namespace(current->nsproxy->namespace);
         } else {
                 mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt);
                 commit_tree(source_mnt);
@@ -1441,7 +1441,7 @@ dput_out:
  */
 struct namespace *dup_namespace(struct task_struct *tsk, struct fs_struct *fs)
 {
-        struct namespace *namespace = tsk->namespace;
+        struct namespace *namespace = tsk->nsproxy->namespace;
         struct namespace *new_ns;
         struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL;
         struct vfsmount *p, *q;
@@ -1508,7 +1508,7 @@ struct namespace *dup_namespace(struct task_struct *tsk, struct fs_struct *fs)
 
 int copy_namespace(int flags, struct task_struct *tsk)
 {
-        struct namespace *namespace = tsk->namespace;
+        struct namespace *namespace = tsk->nsproxy->namespace;
         struct namespace *new_ns;
         int err = 0;
 
@@ -1531,7 +1531,7 @@ int copy_namespace(int flags, struct task_struct *tsk)
                 goto out;
         }
 
-        tsk->namespace = new_ns;
+        tsk->nsproxy->namespace = new_ns;
 
 out:
         put_namespace(namespace);
@@ -1754,7 +1754,7 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
         detach_mnt(user_nd.mnt, &root_parent);
         attach_mnt(user_nd.mnt, &old_nd);     /* mount old root on put_old */
         attach_mnt(new_nd.mnt, &root_parent); /* mount new_root on / */
-        touch_namespace(current->namespace);
+        touch_namespace(current->nsproxy->namespace);
         spin_unlock(&vfsmount_lock);
         chroot_fs_refs(&user_nd, &new_nd);
         security_sb_post_pivotroot(&user_nd, &new_nd);
@@ -1780,7 +1780,6 @@ static void __init init_mount_tree(void)
 {
         struct vfsmount *mnt;
         struct namespace *namespace;
-        struct task_struct *g, *p;
 
         mnt = do_kern_mount("rootfs", 0, "rootfs", NULL);
         if (IS_ERR(mnt))
@@ -1796,13 +1795,8 @@ static void __init init_mount_tree(void)
         namespace->root = mnt;
         mnt->mnt_namespace = namespace;
 
-        init_task.namespace = namespace;
-        read_lock(&tasklist_lock);
-        do_each_thread(g, p) {
-                get_namespace(namespace);
-                p->namespace = namespace;
-        } while_each_thread(g, p);
-        read_unlock(&tasklist_lock);
+        init_task.nsproxy->namespace = namespace;
+        get_namespace(namespace);
 
         set_fs_pwd(current->fs, namespace->root, namespace->root->mnt_root);
         set_fs_root(current->fs, namespace->root, namespace->root->mnt_root);
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 9c6a809f92b6..6d00ccc48c1c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -71,6 +71,7 @@
 #include <linux/cpuset.h>
 #include <linux/audit.h>
 #include <linux/poll.h>
+#include <linux/nsproxy.h>
 #include "internal.h"
 
 /* NOTE:
@@ -473,7 +474,7 @@ static int mounts_open(struct inode *inode, struct file *file)
 
         if (task) {
                 task_lock(task);
-                namespace = task->namespace;
+                namespace = task->nsproxy->namespace;
                 if (namespace)
                         get_namespace(namespace);
                 task_unlock(task);
@@ -544,7 +545,7 @@ static int mountstats_open(struct inode *inode, struct file *file)
 
                 if (task) {
                         task_lock(task);
-                        namespace = task->namespace;
+                        namespace = task->nsproxy->namespace;
                         if (namespace)
                                 get_namespace(namespace);
                         task_unlock(task);
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 8f8bb422a5c7..4865348ca8bd 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -72,6 +72,7 @@ extern struct nsproxy init_nsproxy;
 #define INIT_NSPROXY(nsproxy) {                                         \
         .count          = ATOMIC_INIT(1),                               \
         .nslock         = SPIN_LOCK_UNLOCKED,                           \
+        .namespace      = NULL,                                         \
 }
 
 #define INIT_SIGHAND(sighand) {                                         \
diff --git a/include/linux/namespace.h b/include/linux/namespace.h
index 3abc8e3b4879..d137009f0b2b 100644
--- a/include/linux/namespace.h
+++ b/include/linux/namespace.h
@@ -4,6 +4,7 @@
 
 #include <linux/mount.h>
 #include <linux/sched.h>
+#include <linux/nsproxy.h>
 
 struct namespace {
         atomic_t                count;
@@ -26,11 +27,8 @@ static inline void put_namespace(struct namespace *namespace)
 
 static inline void exit_namespace(struct task_struct *p)
 {
-        struct namespace *namespace = p->namespace;
+        struct namespace *namespace = p->nsproxy->namespace;
         if (namespace) {
-                task_lock(p);
-                p->namespace = NULL;
-                task_unlock(p);
                 put_namespace(namespace);
         }
 }
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 7bdebfaab6a5..7ebe66670c59 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -4,6 +4,8 @@
 #include <linux/spinlock.h>
 #include <linux/sched.h>
 
+struct namespace;
+
 /*
  * A structure to contain pointers to all per-process
  * namespaces - fs (mount), uts, network, sysvipc, etc.
@@ -19,6 +21,7 @@
 struct nsproxy {
         atomic_t count;
         spinlock_t nslock;
+        struct namespace *namespace;
 };
 extern struct nsproxy init_nsproxy;
 
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 4fa631fa55e3..670b89a20070 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -238,7 +238,6 @@ extern signed long schedule_timeout_interruptible(signed long timeout);
 extern signed long schedule_timeout_uninterruptible(signed long timeout);
 asmlinkage void schedule(void);
 
-struct namespace;
 struct nsproxy;
 
 /* Maximum number of active map areas.. This is a random (large) number */
@@ -897,8 +896,7 @@ struct task_struct {
         struct fs_struct *fs;
 /* open file information */
         struct files_struct *files;
-/* namespace */
-        struct namespace *namespace;
+/* namespaces */
         struct nsproxy *nsproxy;
 /* signal handlers */
         struct signal_struct *signal;
diff --git a/kernel/exit.c b/kernel/exit.c
index 1d0e9ea1fa05..741bbe42dfe8 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -399,11 +399,8 @@ void daemonize(const char *name, ...)
         current->fs = fs;
         atomic_inc(&fs->count);
 
-        exit_namespace(current);
         exit_task_namespaces(current);
-        current->namespace = init_task.namespace;
         current->nsproxy = init_task.nsproxy;
-        get_namespace(current->namespace);
         get_task_namespaces(current);
 
         exit_files(current);
@@ -923,7 +920,6 @@ fastcall NORET_TYPE void do_exit(long code)
         exit_sem(tsk);
         __exit_files(tsk);
         __exit_fs(tsk);
-        exit_namespace(tsk);
         exit_task_namespaces(tsk);
         exit_thread();
         cpuset_exit(tsk);
diff --git a/kernel/fork.c b/kernel/fork.c
index c9e660ae47aa..33fcf0733ca6 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1119,11 +1119,9 @@ static struct task_struct *copy_process(unsigned long clone_flags,
                 goto bad_fork_cleanup_mm;
         if ((retval = copy_namespaces(clone_flags, p)))
                 goto bad_fork_cleanup_keys;
-        if ((retval = copy_namespace(clone_flags, p)))
-                goto bad_fork_cleanup_namespaces;
         retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
         if (retval)
-                goto bad_fork_cleanup_namespace;
+                goto bad_fork_cleanup_namespaces;
 
         p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
         /*
@@ -1215,7 +1213,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
                 spin_unlock(&current->sighand->siglock);
                 write_unlock_irq(&tasklist_lock);
                 retval = -ERESTARTNOINTR;
-                goto bad_fork_cleanup_namespace;
+                goto bad_fork_cleanup_namespaces;
         }
 
         if (clone_flags & CLONE_THREAD) {
@@ -1263,8 +1261,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         proc_fork_connector(p);
         return p;
 
-bad_fork_cleanup_namespace:
-        exit_namespace(p);
 bad_fork_cleanup_namespaces:
         exit_task_namespaces(p);
 bad_fork_cleanup_keys:
@@ -1519,10 +1515,9 @@ static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
  */
 static int unshare_namespace(unsigned long unshare_flags, struct namespace **new_nsp, struct fs_struct *new_fs)
 {
-        struct namespace *ns = current->namespace;
+        struct namespace *ns = current->nsproxy->namespace;
 
-        if ((unshare_flags & CLONE_NEWNS) &&
-            (ns && atomic_read(&ns->count) > 1)) {
+        if ((unshare_flags & CLONE_NEWNS) && ns) {
                 if (!capable(CAP_SYS_ADMIN))
                         return -EPERM;
 
@@ -1655,8 +1650,8 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
                 }
 
                 if (new_ns) {
-                        ns = current->namespace;
-                        current->namespace = new_ns;
+                        ns = current->nsproxy->namespace;
+                        current->nsproxy->namespace = new_ns;
                         new_ns = ns;
                 }
 
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index a3612f82f187..e10385c17f73 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -13,6 +13,7 @@
 #include <linux/version.h>
 #include <linux/nsproxy.h>
 #include <linux/init_task.h>
+#include <linux/namespace.h>
 
 struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
 
@@ -55,6 +56,11 @@ struct nsproxy *dup_namespaces(struct nsproxy *orig)
 {
         struct nsproxy *ns = clone_namespaces(orig);
 
+        if (ns) {
+                if (ns->namespace)
+                        get_namespace(ns->namespace);
+        }
+
         return ns;
 }
 
@@ -65,16 +71,40 @@ struct nsproxy *dup_namespaces(struct nsproxy *orig)
 int copy_namespaces(int flags, struct task_struct *tsk)
 {
         struct nsproxy *old_ns = tsk->nsproxy;
+        struct nsproxy *new_ns;
+        int err = 0;
 
         if (!old_ns)
                 return 0;
 
         get_nsproxy(old_ns);
 
-        return 0;
+        if (!(flags & CLONE_NEWNS))
+                return 0;
+
+        new_ns = clone_namespaces(old_ns);
+        if (!new_ns) {
+                err = -ENOMEM;
+                goto out;
+        }
+
+        tsk->nsproxy = new_ns;
+
+        err = copy_namespace(flags, tsk);
+        if (err) {
+                tsk->nsproxy = old_ns;
+                put_nsproxy(new_ns);
+                goto out;
+        }
+
+out:
+        put_nsproxy(old_ns);
+        return err;
 }
 
 void free_nsproxy(struct nsproxy *ns)
 {
+                if (ns->namespace)
+                        put_namespace(ns->namespace);
                 kfree(ns);
 }