[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 66d921e14feebaa532bed7e6a041ba08e5057a8c..55442a6cf22133d2c9687636b3e3ca788eacac53 100644 (file)
--- 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 9c6a809f92b69228c8ce2ea99d29438a5095b50f..6d00ccc48c1cb43cf6b2f05fb063d43cb3cf4a1c 100644 (file)
--- 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 8f8bb422a5c7e39f837bf0dc3c291fa52380dd6c..4865348ca8bd692330b7aa55358a7bcc15514814 100644 (file)
--- 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 3abc8e3b4879a5eac2dd54374f0fb9b37ca9f3a7..d137009f0b2be0feb70efcffba537f899195865d 100644 (file)
--- 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 7bdebfaab6a5b18c4b9523f70efe3c7b7b1c37e6..7ebe66670c592d64cba6b829ce42307b141e44cb 100644 (file)
--- 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 4fa631fa55e357cfa9cd483c4fe2761a25b115fe..670b89a20070c9d5a2283faa1a6f0346ce7b2f4a 100644 (file)
--- 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 1d0e9ea1fa0592b0b1bdf3104e71cc239ffbb256..741bbe42dfe8a5e2ceae75ed4bb57c7b4bf4a136 100644 (file)
--- 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 c9e660ae47aa89ad266e5f944d67c5cd8d9704ef..33fcf0733ca64bc4ab7aeab0442ef49d57bcbbc0 100644 (file)
--- 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 a3612f82f187266a10dc8b79e1fbd26fb964f6e9..e10385c17f73766e9373992d6e4497192b664b95 100644 (file)
--- 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);
 }