[PATCH] namespaces: incorporate fs namespace into nsproxy

This moves the mount namespace into the nsproxy.  The mount namespace count
now refers to the number of nsproxies point to it, rather than the number of
tasks.  As a result, the unshare_namespace() function in kernel/fork.c no
longer checks whether it is being shared.

Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 11 insertions, 16 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 66d921e..55442a6 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 9c6a809..6d00ccc 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);