[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>
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 @@
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 @@
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 @@
*/
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 @@
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 @@
goto out;
}
- tsk->namespace = new_ns;
+ tsk->nsproxy->namespace = new_ns;
out:
put_namespace(namespace);
@@ -1754,7 +1754,7 @@
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 @@
{
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 @@
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 @@
if (task) {
task_lock(task);
- namespace = task->namespace;
+ namespace = task->nsproxy->namespace;
if (namespace)
get_namespace(namespace);
task_unlock(task);
@@ -544,7 +545,7 @@
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 8f8bb42..4865348 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -72,6 +72,7 @@
#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 3abc8e3..d137009 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 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 7bdebfa..7ebe666 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 4fa631f..670b89a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -238,7 +238,6 @@
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 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 1d0e9ea..741bbe4 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -399,11 +399,8 @@
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 @@
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 c9e660a..33fcf07 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1119,11 +1119,9 @@
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 @@
spin_unlock(¤t->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 @@
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_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 @@
}
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 a3612f8..e10385c 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 *ns = clone_namespaces(orig);
+ if (ns) {
+ if (ns->namespace)
+ get_namespace(ns->namespace);
+ }
+
return ns;
}
@@ -65,16 +71,40 @@
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);
}