Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1465 insertions, 0 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
new file mode 100644
index 000000000000..3b93e5d750eb
--- /dev/null
+++ b/fs/namespace.c
@@ -0,0 +1,1465 @@
+/*
+ *  linux/fs/namespace.c
+ *
+ * (C) Copyright Al Viro 2000, 2001
+ *      Released under GPL v2.
+ *
+ * Based on code from fs/super.c, copyright Linus Torvalds and others.
+ * Heavily rewritten.
+ */
+
+#include <linux/config.h>
+#include <linux/syscalls.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/smp_lock.h>
+#include <linux/init.h>
+#include <linux/quotaops.h>
+#include <linux/acct.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/namespace.h>
+#include <linux/namei.h>
+#include <linux/security.h>
+#include <linux/mount.h>
+#include <asm/uaccess.h>
+#include <asm/unistd.h>
+
+extern int __init init_rootfs(void);
+
+#ifdef CONFIG_SYSFS
+extern int __init sysfs_init(void);
+#else
+static inline int sysfs_init(void)
+{
+        return 0;
+}
+#endif
+
+/* spinlock for vfsmount related operations, inplace of dcache_lock */
+ __cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
+
+static struct list_head *mount_hashtable;
+static int hash_mask, hash_bits;
+static kmem_cache_t *mnt_cache; 
+
+static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)
+{
+        unsigned long tmp = ((unsigned long) mnt / L1_CACHE_BYTES);
+        tmp += ((unsigned long) dentry / L1_CACHE_BYTES);
+        tmp = tmp + (tmp >> hash_bits);
+        return tmp & hash_mask;
+}
+
+struct vfsmount *alloc_vfsmnt(const char *name)
+{
+        struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL); 
+        if (mnt) {
+                memset(mnt, 0, sizeof(struct vfsmount));
+                atomic_set(&mnt->mnt_count,1);
+                INIT_LIST_HEAD(&mnt->mnt_hash);
+                INIT_LIST_HEAD(&mnt->mnt_child);
+                INIT_LIST_HEAD(&mnt->mnt_mounts);
+                INIT_LIST_HEAD(&mnt->mnt_list);
+                INIT_LIST_HEAD(&mnt->mnt_fslink);
+                if (name) {
+                        int size = strlen(name)+1;
+                        char *newname = kmalloc(size, GFP_KERNEL);
+                        if (newname) {
+                                memcpy(newname, name, size);
+                                mnt->mnt_devname = newname;
+                        }
+                }
+        }
+        return mnt;
+}
+
+void free_vfsmnt(struct vfsmount *mnt)
+{
+        kfree(mnt->mnt_devname);
+        kmem_cache_free(mnt_cache, mnt);
+}
+
+/*
+ * Now, lookup_mnt increments the ref count before returning
+ * the vfsmount struct.
+ */
+struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
+{
+        struct list_head * head = mount_hashtable + hash(mnt, dentry);
+        struct list_head * tmp = head;
+        struct vfsmount *p, *found = NULL;
+
+        spin_lock(&vfsmount_lock);
+        for (;;) {
+                tmp = tmp->next;
+                p = NULL;
+                if (tmp == head)
+                        break;
+                p = list_entry(tmp, struct vfsmount, mnt_hash);
+                if (p->mnt_parent == mnt && p->mnt_mountpoint == dentry) {
+                        found = mntget(p);
+                        break;
+                }
+        }
+        spin_unlock(&vfsmount_lock);
+        return found;
+}
+
+static inline int check_mnt(struct vfsmount *mnt)
+{
+        return mnt->mnt_namespace == current->namespace;
+}
+
+static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd)
+{
+        old_nd->dentry = mnt->mnt_mountpoint;
+        old_nd->mnt = mnt->mnt_parent;
+        mnt->mnt_parent = mnt;
+        mnt->mnt_mountpoint = mnt->mnt_root;
+        list_del_init(&mnt->mnt_child);
+        list_del_init(&mnt->mnt_hash);
+        old_nd->dentry->d_mounted--;
+}
+
+static void attach_mnt(struct vfsmount *mnt, struct nameidata *nd)
+{
+        mnt->mnt_parent = mntget(nd->mnt);
+        mnt->mnt_mountpoint = dget(nd->dentry);
+        list_add(&mnt->mnt_hash, mount_hashtable+hash(nd->mnt, nd->dentry));
+        list_add_tail(&mnt->mnt_child, &nd->mnt->mnt_mounts);
+        nd->dentry->d_mounted++;
+}
+
+static struct vfsmount *next_mnt(struct vfsmount *p, struct vfsmount *root)
+{
+        struct list_head *next = p->mnt_mounts.next;
+        if (next == &p->mnt_mounts) {
+                while (1) {
+                        if (p == root)
+                                return NULL;
+                        next = p->mnt_child.next;
+                        if (next != &p->mnt_parent->mnt_mounts)
+                                break;
+                        p = p->mnt_parent;
+                }
+        }
+        return list_entry(next, struct vfsmount, mnt_child);
+}
+
+static struct vfsmount *
+clone_mnt(struct vfsmount *old, struct dentry *root)
+{
+        struct super_block *sb = old->mnt_sb;
+        struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname);
+
+        if (mnt) {
+                mnt->mnt_flags = old->mnt_flags;
+                atomic_inc(&sb->s_active);
+                mnt->mnt_sb = sb;
+                mnt->mnt_root = dget(root);
+                mnt->mnt_mountpoint = mnt->mnt_root;
+                mnt->mnt_parent = mnt;
+                mnt->mnt_namespace = old->mnt_namespace;
+
+                /* stick the duplicate mount on the same expiry list
+                 * as the original if that was on one */
+                spin_lock(&vfsmount_lock);
+                if (!list_empty(&old->mnt_fslink))
+                        list_add(&mnt->mnt_fslink, &old->mnt_fslink);
+                spin_unlock(&vfsmount_lock);
+        }
+        return mnt;
+}
+
+void __mntput(struct vfsmount *mnt)
+{
+        struct super_block *sb = mnt->mnt_sb;
+        dput(mnt->mnt_root);
+        free_vfsmnt(mnt);
+        deactivate_super(sb);
+}
+
+EXPORT_SYMBOL(__mntput);
+
+/* iterator */
+static void *m_start(struct seq_file *m, loff_t *pos)
+{
+        struct namespace *n = m->private;
+        struct list_head *p;
+        loff_t l = *pos;
+
+        down_read(&n->sem);
+        list_for_each(p, &n->list)
+                if (!l--)
+                        return list_entry(p, struct vfsmount, mnt_list);
+        return NULL;
+}
+
+static void *m_next(struct seq_file *m, void *v, loff_t *pos)
+{
+        struct namespace *n = m->private;
+        struct list_head *p = ((struct vfsmount *)v)->mnt_list.next;
+        (*pos)++;
+        return p==&n->list ? NULL : list_entry(p, struct vfsmount, mnt_list);
+}
+
+static void m_stop(struct seq_file *m, void *v)
+{
+        struct namespace *n = m->private;
+        up_read(&n->sem);
+}
+
+static inline void mangle(struct seq_file *m, const char *s)
+{
+        seq_escape(m, s, " \t\n\\");
+}
+
+static int show_vfsmnt(struct seq_file *m, void *v)
+{
+        struct vfsmount *mnt = v;
+        int err = 0;
+        static struct proc_fs_info {
+                int flag;
+                char *str;
+        } fs_info[] = {
+                { MS_SYNCHRONOUS, ",sync" },
+                { MS_DIRSYNC, ",dirsync" },
+                { MS_MANDLOCK, ",mand" },
+                { MS_NOATIME, ",noatime" },
+                { MS_NODIRATIME, ",nodiratime" },
+                { 0, NULL }
+        };
+        static struct proc_fs_info mnt_info[] = {
+                { MNT_NOSUID, ",nosuid" },
+                { MNT_NODEV, ",nodev" },
+                { MNT_NOEXEC, ",noexec" },
+                { 0, NULL }
+        };
+        struct proc_fs_info *fs_infop;
+
+        mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
+        seq_putc(m, ' ');
+        seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
+        seq_putc(m, ' ');
+        mangle(m, mnt->mnt_sb->s_type->name);
+        seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? " ro" : " rw");
+        for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
+                if (mnt->mnt_sb->s_flags & fs_infop->flag)
+                        seq_puts(m, fs_infop->str);
+        }
+        for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
+                if (mnt->mnt_flags & fs_infop->flag)
+                        seq_puts(m, fs_infop->str);
+        }
+        if (mnt->mnt_sb->s_op->show_options)
+                err = mnt->mnt_sb->s_op->show_options(m, mnt);
+        seq_puts(m, " 0 0\n");
+        return err;
+}
+
+struct seq_operations mounts_op = {
+        .start  = m_start,
+        .next   = m_next,
+        .stop   = m_stop,
+        .show   = show_vfsmnt
+};
+
+/**
+ * may_umount_tree - check if a mount tree is busy
+ * @mnt: root of mount tree
+ *
+ * This is called to check if a tree of mounts has any
+ * open files, pwds, chroots or sub mounts that are
+ * busy.
+ */
+int may_umount_tree(struct vfsmount *mnt)
+{
+        struct list_head *next;
+        struct vfsmount *this_parent = mnt;
+        int actual_refs;
+        int minimum_refs;
+
+        spin_lock(&vfsmount_lock);
+        actual_refs = atomic_read(&mnt->mnt_count);
+        minimum_refs = 2;
+repeat:
+        next = this_parent->mnt_mounts.next;
+resume:
+        while (next != &this_parent->mnt_mounts) {
+                struct vfsmount *p = list_entry(next, struct vfsmount, mnt_child);
+
+                next = next->next;
+
+                actual_refs += atomic_read(&p->mnt_count);
+                minimum_refs += 2;
+
+                if (!list_empty(&p->mnt_mounts)) {
+                        this_parent = p;
+                        goto repeat;
+                }
+        }
+
+        if (this_parent != mnt) {
+                next = this_parent->mnt_child.next;
+                this_parent = this_parent->mnt_parent;
+                goto resume;
+        }
+        spin_unlock(&vfsmount_lock);
+
+        if (actual_refs > minimum_refs)
+                return -EBUSY;
+
+        return 0;
+}
+
+EXPORT_SYMBOL(may_umount_tree);
+
+/**
+ * may_umount - check if a mount point is busy
+ * @mnt: root of mount
+ *
+ * This is called to check if a mount point has any
+ * open files, pwds, chroots or sub mounts. If the
+ * mount has sub mounts this will return busy
+ * regardless of whether the sub mounts are busy.
+ *
+ * Doesn't take quota and stuff into account. IOW, in some cases it will
+ * give false negatives. The main reason why it's here is that we need
+ * a non-destructive way to look for easily umountable filesystems.
+ */
+int may_umount(struct vfsmount *mnt)
+{
+        if (atomic_read(&mnt->mnt_count) > 2)
+                return -EBUSY;
+        return 0;
+}
+
+EXPORT_SYMBOL(may_umount);
+
+void umount_tree(struct vfsmount *mnt)
+{
+        struct vfsmount *p;
+        LIST_HEAD(kill);
+
+        for (p = mnt; p; p = next_mnt(p, mnt)) {
+                list_del(&p->mnt_list);
+                list_add(&p->mnt_list, &kill);
+        }
+
+        while (!list_empty(&kill)) {
+                mnt = list_entry(kill.next, struct vfsmount, mnt_list);
+                list_del_init(&mnt->mnt_list);
+                list_del_init(&mnt->mnt_fslink);
+                if (mnt->mnt_parent == mnt) {
+                        spin_unlock(&vfsmount_lock);
+                } else {
+                        struct nameidata old_nd;
+                        detach_mnt(mnt, &old_nd);
+                        spin_unlock(&vfsmount_lock);
+                        path_release(&old_nd);
+                }
+                mntput(mnt);
+                spin_lock(&vfsmount_lock);
+        }
+}
+
+static int do_umount(struct vfsmount *mnt, int flags)
+{
+        struct super_block * sb = mnt->mnt_sb;
+        int retval;
+
+        retval = security_sb_umount(mnt, flags);
+        if (retval)
+                return retval;
+
+        /*
+         * Allow userspace to request a mountpoint be expired rather than
+         * unmounting unconditionally. Unmount only happens if:
+         *  (1) the mark is already set (the mark is cleared by mntput())
+         *  (2) the usage count == 1 [parent vfsmount] + 1 [sys_umount]
+         */
+        if (flags & MNT_EXPIRE) {
+                if (mnt == current->fs->rootmnt ||
+                    flags & (MNT_FORCE | MNT_DETACH))
+                        return -EINVAL;
+
+                if (atomic_read(&mnt->mnt_count) != 2)
+                        return -EBUSY;
+
+                if (!xchg(&mnt->mnt_expiry_mark, 1))
+                        return -EAGAIN;
+        }
+
+        /*
+         * If we may have to abort operations to get out of this
+         * mount, and they will themselves hold resources we must
+         * allow the fs to do things. In the Unix tradition of
+         * 'Gee thats tricky lets do it in userspace' the umount_begin
+         * might fail to complete on the first run through as other tasks
+         * must return, and the like. Thats for the mount program to worry
+         * about for the moment.
+         */
+
+        lock_kernel();
+        if( (flags&MNT_FORCE) && sb->s_op->umount_begin)
+                sb->s_op->umount_begin(sb);
+        unlock_kernel();
+
+        /*
+         * No sense to grab the lock for this test, but test itself looks
+         * somewhat bogus. Suggestions for better replacement?
+         * Ho-hum... In principle, we might treat that as umount + switch
+         * to rootfs. GC would eventually take care of the old vfsmount.
+         * Actually it makes sense, especially if rootfs would contain a
+         * /reboot - static binary that would close all descriptors and
+         * call reboot(9). Then init(8) could umount root and exec /reboot.
+         */
+        if (mnt == current->fs->rootmnt && !(flags & MNT_DETACH)) {
+                /*
+                 * Special case for "unmounting" root ...
+                 * we just try to remount it readonly.
+                 */
+                down_write(&sb->s_umount);
+                if (!(sb->s_flags & MS_RDONLY)) {
+                        lock_kernel();
+                        DQUOT_OFF(sb);
+                        retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
+                        unlock_kernel();
+                }
+                up_write(&sb->s_umount);
+                return retval;
+        }
+
+        down_write(&current->namespace->sem);
+        spin_lock(&vfsmount_lock);
+
+        if (atomic_read(&sb->s_active) == 1) {
+                /* last instance - try to be smart */
+                spin_unlock(&vfsmount_lock);
+                lock_kernel();
+                DQUOT_OFF(sb);
+                acct_auto_close(sb);
+                unlock_kernel();
+                security_sb_umount_close(mnt);
+                spin_lock(&vfsmount_lock);
+        }
+        retval = -EBUSY;
+        if (atomic_read(&mnt->mnt_count) == 2 || flags & MNT_DETACH) {
+                if (!list_empty(&mnt->mnt_list))
+                        umount_tree(mnt);
+                retval = 0;
+        }
+        spin_unlock(&vfsmount_lock);
+        if (retval)
+                security_sb_umount_busy(mnt);
+        up_write(&current->namespace->sem);
+        return retval;
+}
+
+/*
+ * Now umount can handle mount points as well as block devices.
+ * This is important for filesystems which use unnamed block devices.
+ *
+ * We now support a flag for forced unmount like the other 'big iron'
+ * unixes. Our API is identical to OSF/1 to avoid making a mess of AMD
+ */
+
+asmlinkage long sys_umount(char __user * name, int flags)
+{
+        struct nameidata nd;
+        int retval;
+
+        retval = __user_walk(name, LOOKUP_FOLLOW, &nd);
+        if (retval)
+                goto out;
+        retval = -EINVAL;
+        if (nd.dentry != nd.mnt->mnt_root)
+                goto dput_and_out;
+        if (!check_mnt(nd.mnt))
+                goto dput_and_out;
+
+        retval = -EPERM;
+        if (!capable(CAP_SYS_ADMIN))
+                goto dput_and_out;
+
+        retval = do_umount(nd.mnt, flags);
+dput_and_out:
+        path_release_on_umount(&nd);
+out:
+        return retval;
+}
+
+#ifdef __ARCH_WANT_SYS_OLDUMOUNT
+
+/*
+ *      The 2.0 compatible umount. No flags. 
+ */
+ 
+asmlinkage long sys_oldumount(char __user * name)
+{
+        return sys_umount(name,0);
+}
+
+#endif
+
+static int mount_is_safe(struct nameidata *nd)
+{
+        if (capable(CAP_SYS_ADMIN))
+                return 0;
+        return -EPERM;
+#ifdef notyet
+        if (S_ISLNK(nd->dentry->d_inode->i_mode))
+                return -EPERM;
+        if (nd->dentry->d_inode->i_mode & S_ISVTX) {
+                if (current->uid != nd->dentry->d_inode->i_uid)
+                        return -EPERM;
+        }
+        if (permission(nd->dentry->d_inode, MAY_WRITE, nd))
+                return -EPERM;
+        return 0;
+#endif
+}
+
+static int
+lives_below_in_same_fs(struct dentry *d, struct dentry *dentry)
+{
+        while (1) {
+                if (d == dentry)
+                        return 1;
+                if (d == NULL || d == d->d_parent)
+                        return 0;
+                d = d->d_parent;
+        }
+}
+
+static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry)
+{
+        struct vfsmount *res, *p, *q, *r, *s;
+        struct list_head *h;
+        struct nameidata nd;
+
+        res = q = clone_mnt(mnt, dentry);
+        if (!q)
+                goto Enomem;
+        q->mnt_mountpoint = mnt->mnt_mountpoint;
+
+        p = mnt;
+        for (h = mnt->mnt_mounts.next; h != &mnt->mnt_mounts; h = h->next) {
+                r = list_entry(h, struct vfsmount, mnt_child);
+                if (!lives_below_in_same_fs(r->mnt_mountpoint, dentry))
+                        continue;
+
+                for (s = r; s; s = next_mnt(s, r)) {
+                        while (p != s->mnt_parent) {
+                                p = p->mnt_parent;
+                                q = q->mnt_parent;
+                        }
+                        p = s;
+                        nd.mnt = q;
+                        nd.dentry = p->mnt_mountpoint;
+                        q = clone_mnt(p, p->mnt_root);
+                        if (!q)
+                                goto Enomem;
+                        spin_lock(&vfsmount_lock);
+                        list_add_tail(&q->mnt_list, &res->mnt_list);
+                        attach_mnt(q, &nd);
+                        spin_unlock(&vfsmount_lock);
+                }
+        }
+        return res;
+ Enomem:
+        if (res) {
+                spin_lock(&vfsmount_lock);
+                umount_tree(res);
+                spin_unlock(&vfsmount_lock);
+        }
+        return NULL;
+}
+
+static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
+{
+        int err;
+        if (mnt->mnt_sb->s_flags & MS_NOUSER)
+                return -EINVAL;
+
+        if (S_ISDIR(nd->dentry->d_inode->i_mode) !=
+              S_ISDIR(mnt->mnt_root->d_inode->i_mode))
+                return -ENOTDIR;
+
+        err = -ENOENT;
+        down(&nd->dentry->d_inode->i_sem);
+        if (IS_DEADDIR(nd->dentry->d_inode))
+                goto out_unlock;
+
+        err = security_sb_check_sb(mnt, nd);
+        if (err)
+                goto out_unlock;
+
+        err = -ENOENT;
+        spin_lock(&vfsmount_lock);
+        if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry)) {
+                struct list_head head;
+
+                attach_mnt(mnt, nd);
+                list_add_tail(&head, &mnt->mnt_list);
+                list_splice(&head, current->namespace->list.prev);
+                mntget(mnt);
+                err = 0;
+        }
+        spin_unlock(&vfsmount_lock);
+out_unlock:
+        up(&nd->dentry->d_inode->i_sem);
+        if (!err)
+                security_sb_post_addmount(mnt, nd);
+        return err;
+}
+
+/*
+ * do loopback mount.
+ */
+static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
+{
+        struct nameidata old_nd;
+        struct vfsmount *mnt = NULL;
+        int err = mount_is_safe(nd);
+        if (err)
+                return err;
+        if (!old_name || !*old_name)
+                return -EINVAL;
+        err = path_lookup(old_name, LOOKUP_FOLLOW, &old_nd);
+        if (err)
+                return err;
+
+        down_write(&current->namespace->sem);
+        err = -EINVAL;
+        if (check_mnt(nd->mnt) && (!recurse || check_mnt(old_nd.mnt))) {
+                err = -ENOMEM;
+                if (recurse)
+                        mnt = copy_tree(old_nd.mnt, old_nd.dentry);
+                else
+                        mnt = clone_mnt(old_nd.mnt, old_nd.dentry);
+        }
+
+        if (mnt) {
+                /* stop bind mounts from expiring */
+                spin_lock(&vfsmount_lock);
+                list_del_init(&mnt->mnt_fslink);
+                spin_unlock(&vfsmount_lock);
+
+                err = graft_tree(mnt, nd);
+                if (err) {
+                        spin_lock(&vfsmount_lock);
+                        umount_tree(mnt);
+                        spin_unlock(&vfsmount_lock);
+                } else
+                        mntput(mnt);
+        }
+
+        up_write(&current->namespace->sem);
+        path_release(&old_nd);
+        return err;
+}
+
+/*
+ * change filesystem flags. dir should be a physical root of filesystem.
+ * If you've mounted a non-root directory somewhere and want to do remount
+ * on it - tough luck.
+ */
+
+static int do_remount(struct nameidata *nd, int flags, int mnt_flags,
+                      void *data)
+{
+        int err;
+        struct super_block * sb = nd->mnt->mnt_sb;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        if (!check_mnt(nd->mnt))
+                return -EINVAL;
+
+        if (nd->dentry != nd->mnt->mnt_root)
+                return -EINVAL;
+
+        down_write(&sb->s_umount);
+        err = do_remount_sb(sb, flags, data, 0);
+        if (!err)
+                nd->mnt->mnt_flags=mnt_flags;
+        up_write(&sb->s_umount);
+        if (!err)
+                security_sb_post_remount(nd->mnt, flags, data);
+        return err;
+}
+
+static int do_move_mount(struct nameidata *nd, char *old_name)
+{
+        struct nameidata old_nd, parent_nd;
+        struct vfsmount *p;
+        int err = 0;
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+        if (!old_name || !*old_name)
+                return -EINVAL;
+        err = path_lookup(old_name, LOOKUP_FOLLOW, &old_nd);
+        if (err)
+                return err;
+
+        down_write(&current->namespace->sem);
+        while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
+                ;
+        err = -EINVAL;
+        if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt))
+                goto out;
+
+        err = -ENOENT;
+        down(&nd->dentry->d_inode->i_sem);
+        if (IS_DEADDIR(nd->dentry->d_inode))
+                goto out1;
+
+        spin_lock(&vfsmount_lock);
+        if (!IS_ROOT(nd->dentry) && d_unhashed(nd->dentry))
+                goto out2;
+
+        err = -EINVAL;
+        if (old_nd.dentry != old_nd.mnt->mnt_root)
+                goto out2;
+
+        if (old_nd.mnt == old_nd.mnt->mnt_parent)
+                goto out2;
+
+        if (S_ISDIR(nd->dentry->d_inode->i_mode) !=
+              S_ISDIR(old_nd.dentry->d_inode->i_mode))
+                goto out2;
+
+        err = -ELOOP;
+        for (p = nd->mnt; p->mnt_parent!=p; p = p->mnt_parent)
+                if (p == old_nd.mnt)
+                        goto out2;
+        err = 0;
+
+        detach_mnt(old_nd.mnt, &parent_nd);
+        attach_mnt(old_nd.mnt, nd);
+
+        /* if the mount is moved, it should no longer be expire
+         * automatically */
+        list_del_init(&old_nd.mnt->mnt_fslink);
+out2:
+        spin_unlock(&vfsmount_lock);
+out1:
+        up(&nd->dentry->d_inode->i_sem);
+out:
+        up_write(&current->namespace->sem);
+        if (!err)
+                path_release(&parent_nd);
+        path_release(&old_nd);
+        return err;
+}
+
+/*
+ * create a new mount for userspace and request it to be added into the
+ * namespace's tree
+ */
+static int do_new_mount(struct nameidata *nd, char *type, int flags,
+                        int mnt_flags, char *name, void *data)
+{
+        struct vfsmount *mnt;
+
+        if (!type || !memchr(type, 0, PAGE_SIZE))
+                return -EINVAL;
+
+        /* we need capabilities... */
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        mnt = do_kern_mount(type, flags, name, data);
+        if (IS_ERR(mnt))
+                return PTR_ERR(mnt);
+
+        return do_add_mount(mnt, nd, mnt_flags, NULL);
+}
+
+/*
+ * add a mount into a namespace's mount tree
+ * - provide the option of adding the new mount to an expiration list
+ */
+int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
+                 int mnt_flags, struct list_head *fslist)
+{
+        int err;
+
+        down_write(&current->namespace->sem);
+        /* Something was mounted here while we slept */
+        while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
+                ;
+        err = -EINVAL;
+        if (!check_mnt(nd->mnt))
+                goto unlock;
+
+        /* Refuse the same filesystem on the same mount point */
+        err = -EBUSY;
+        if (nd->mnt->mnt_sb == newmnt->mnt_sb &&
+            nd->mnt->mnt_root == nd->dentry)
+                goto unlock;
+
+        err = -EINVAL;
+        if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode))
+                goto unlock;
+
+        newmnt->mnt_flags = mnt_flags;
+        err = graft_tree(newmnt, nd);
+
+        if (err == 0 && fslist) {
+                /* add to the specified expiration list */
+                spin_lock(&vfsmount_lock);
+                list_add_tail(&newmnt->mnt_fslink, fslist);
+                spin_unlock(&vfsmount_lock);
+        }
+
+unlock:
+        up_write(&current->namespace->sem);
+        mntput(newmnt);
+        return err;
+}
+
+EXPORT_SYMBOL_GPL(do_add_mount);
+
+/*
+ * process a list of expirable mountpoints with the intent of discarding any
+ * mountpoints that aren't in use and haven't been touched since last we came
+ * here
+ */
+void mark_mounts_for_expiry(struct list_head *mounts)
+{
+        struct namespace *namespace;
+        struct vfsmount *mnt, *next;
+        LIST_HEAD(graveyard);
+
+        if (list_empty(mounts))
+                return;
+
+        spin_lock(&vfsmount_lock);
+
+        /* extract from the expiration list every vfsmount that matches the
+         * following criteria:
+         * - only referenced by its parent vfsmount
+         * - still marked for expiry (marked on the last call here; marks are
+         *   cleared by mntput())
+         */
+        list_for_each_entry_safe(mnt, next, mounts, mnt_fslink) {
+                if (!xchg(&mnt->mnt_expiry_mark, 1) ||
+                    atomic_read(&mnt->mnt_count) != 1)
+                        continue;
+
+                mntget(mnt);
+                list_move(&mnt->mnt_fslink, &graveyard);
+        }
+
+        /*
+         * go through the vfsmounts we've just consigned to the graveyard to
+         * - check that they're still dead
+         * - delete the vfsmount from the appropriate namespace under lock
+         * - dispose of the corpse
+         */
+        while (!list_empty(&graveyard)) {
+                mnt = list_entry(graveyard.next, struct vfsmount, mnt_fslink);
+                list_del_init(&mnt->mnt_fslink);
+
+                /* don't do anything if the namespace is dead - all the
+                 * vfsmounts from it are going away anyway */
+                namespace = mnt->mnt_namespace;
+                if (!namespace || atomic_read(&namespace->count) <= 0)
+                        continue;
+                get_namespace(namespace);
+
+                spin_unlock(&vfsmount_lock);
+                down_write(&namespace->sem);
+                spin_lock(&vfsmount_lock);
+
+                /* check that it is still dead: the count should now be 2 - as
+                 * contributed by the vfsmount parent and the mntget above */
+                if (atomic_read(&mnt->mnt_count) == 2) {
+                        struct vfsmount *xdmnt;
+                        struct dentry *xdentry;
+
+                        /* delete from the namespace */
+                        list_del_init(&mnt->mnt_list);
+                        list_del_init(&mnt->mnt_child);
+                        list_del_init(&mnt->mnt_hash);
+                        mnt->mnt_mountpoint->d_mounted--;
+
+                        xdentry = mnt->mnt_mountpoint;
+                        mnt->mnt_mountpoint = mnt->mnt_root;
+                        xdmnt = mnt->mnt_parent;
+                        mnt->mnt_parent = mnt;
+
+                        spin_unlock(&vfsmount_lock);
+
+                        mntput(xdmnt);
+                        dput(xdentry);
+
+                        /* now lay it to rest if this was the last ref on the
+                         * superblock */
+                        if (atomic_read(&mnt->mnt_sb->s_active) == 1) {
+                                /* last instance - try to be smart */
+                                lock_kernel();
+                                DQUOT_OFF(mnt->mnt_sb);
+                                acct_auto_close(mnt->mnt_sb);
+                                unlock_kernel();
+                        }
+
+                        mntput(mnt);
+                } else {
+                        /* someone brought it back to life whilst we didn't
+                         * have any locks held so return it to the expiration
+                         * list */
+                        list_add_tail(&mnt->mnt_fslink, mounts);
+                        spin_unlock(&vfsmount_lock);
+                }
+
+                up_write(&namespace->sem);
+
+                mntput(mnt);
+                put_namespace(namespace);
+
+                spin_lock(&vfsmount_lock);
+        }
+
+        spin_unlock(&vfsmount_lock);
+}
+
+EXPORT_SYMBOL_GPL(mark_mounts_for_expiry);
+
+/*
+ * Some copy_from_user() implementations do not return the exact number of
+ * bytes remaining to copy on a fault.  But copy_mount_options() requires that.
+ * Note that this function differs from copy_from_user() in that it will oops
+ * on bad values of `to', rather than returning a short copy.
+ */
+static long
+exact_copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+        char *t = to;
+        const char __user *f = from;
+        char c;
+
+        if (!access_ok(VERIFY_READ, from, n))
+                return n;
+
+        while (n) {
+                if (__get_user(c, f)) {
+                        memset(t, 0, n);
+                        break;
+                }
+                *t++ = c;
+                f++;
+                n--;
+        }
+        return n;
+}
+
+int copy_mount_options(const void __user *data, unsigned long *where)
+{
+        int i;
+        unsigned long page;
+        unsigned long size;
+        
+        *where = 0;
+        if (!data)
+                return 0;
+
+        if (!(page = __get_free_page(GFP_KERNEL)))
+                return -ENOMEM;
+
+        /* We only care that *some* data at the address the user
+         * gave us is valid.  Just in case, we'll zero
+         * the remainder of the page.
+         */
+        /* copy_from_user cannot cross TASK_SIZE ! */
+        size = TASK_SIZE - (unsigned long)data;
+        if (size > PAGE_SIZE)
+                size = PAGE_SIZE;
+
+        i = size - exact_copy_from_user((void *)page, data, size);
+        if (!i) {
+                free_page(page); 
+                return -EFAULT;
+        }
+        if (i != PAGE_SIZE)
+                memset((char *)page + i, 0, PAGE_SIZE - i);
+        *where = page;
+        return 0;
+}
+
+/*
+ * Flags is a 32-bit value that allows up to 31 non-fs dependent flags to
+ * be given to the mount() call (ie: read-only, no-dev, no-suid etc).
+ *
+ * data is a (void *) that can point to any structure up to
+ * PAGE_SIZE-1 bytes, which can contain arbitrary fs-dependent
+ * information (or be NULL).
+ *
+ * Pre-0.97 versions of mount() didn't have a flags word.
+ * When the flags word was introduced its top half was required
+ * to have the magic value 0xC0ED, and this remained so until 2.4.0-test9.
+ * Therefore, if this magic number is present, it carries no information
+ * and must be discarded.
+ */
+long do_mount(char * dev_name, char * dir_name, char *type_page,
+                  unsigned long flags, void *data_page)
+{
+        struct nameidata nd;
+        int retval = 0;
+        int mnt_flags = 0;
+
+        /* Discard magic */
+        if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
+                flags &= ~MS_MGC_MSK;
+
+        /* Basic sanity checks */
+
+        if (!dir_name || !*dir_name || !memchr(dir_name, 0, PAGE_SIZE))
+                return -EINVAL;
+        if (dev_name && !memchr(dev_name, 0, PAGE_SIZE))
+                return -EINVAL;
+
+        if (data_page)
+                ((char *)data_page)[PAGE_SIZE - 1] = 0;
+
+        /* Separate the per-mountpoint flags */
+        if (flags & MS_NOSUID)
+                mnt_flags |= MNT_NOSUID;
+        if (flags & MS_NODEV)
+                mnt_flags |= MNT_NODEV;
+        if (flags & MS_NOEXEC)
+                mnt_flags |= MNT_NOEXEC;
+        flags &= ~(MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_ACTIVE);
+
+        /* ... and get the mountpoint */
+        retval = path_lookup(dir_name, LOOKUP_FOLLOW, &nd);
+        if (retval)
+                return retval;
+
+        retval = security_sb_mount(dev_name, &nd, type_page, flags, data_page);
+        if (retval)
+                goto dput_out;
+
+        if (flags & MS_REMOUNT)
+                retval = do_remount(&nd, flags & ~MS_REMOUNT, mnt_flags,
+                                    data_page);
+        else if (flags & MS_BIND)
+                retval = do_loopback(&nd, dev_name, flags & MS_REC);
+        else if (flags & MS_MOVE)
+                retval = do_move_mount(&nd, dev_name);
+        else
+                retval = do_new_mount(&nd, type_page, flags, mnt_flags,
+                                      dev_name, data_page);
+dput_out:
+        path_release(&nd);
+        return retval;
+}
+
+int copy_namespace(int flags, struct task_struct *tsk)
+{
+        struct namespace *namespace = tsk->namespace;
+        struct namespace *new_ns;
+        struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL;
+        struct fs_struct *fs = tsk->fs;
+        struct vfsmount *p, *q;
+
+        if (!namespace)
+                return 0;
+
+        get_namespace(namespace);
+
+        if (!(flags & CLONE_NEWNS))
+                return 0;
+
+        if (!capable(CAP_SYS_ADMIN)) {
+                put_namespace(namespace);
+                return -EPERM;
+        }
+
+        new_ns = kmalloc(sizeof(struct namespace), GFP_KERNEL);
+        if (!new_ns)
+                goto out;
+
+        atomic_set(&new_ns->count, 1);
+        init_rwsem(&new_ns->sem);
+        INIT_LIST_HEAD(&new_ns->list);
+
+        down_write(&tsk->namespace->sem);
+        /* First pass: copy the tree topology */
+        new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root);
+        if (!new_ns->root) {
+                up_write(&tsk->namespace->sem);
+                kfree(new_ns);
+                goto out;
+        }
+        spin_lock(&vfsmount_lock);
+        list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
+        spin_unlock(&vfsmount_lock);
+
+        /*
+         * Second pass: switch the tsk->fs->* elements and mark new vfsmounts
+         * as belonging to new namespace.  We have already acquired a private
+         * fs_struct, so tsk->fs->lock is not needed.
+         */
+        p = namespace->root;
+        q = new_ns->root;
+        while (p) {
+                q->mnt_namespace = new_ns;
+                if (fs) {
+                        if (p == fs->rootmnt) {
+                                rootmnt = p;
+                                fs->rootmnt = mntget(q);
+                        }
+                        if (p == fs->pwdmnt) {
+                                pwdmnt = p;
+                                fs->pwdmnt = mntget(q);
+                        }
+                        if (p == fs->altrootmnt) {
+                                altrootmnt = p;
+                                fs->altrootmnt = mntget(q);
+                        }
+                }
+                p = next_mnt(p, namespace->root);
+                q = next_mnt(q, new_ns->root);
+        }
+        up_write(&tsk->namespace->sem);
+
+        tsk->namespace = new_ns;
+
+        if (rootmnt)
+                mntput(rootmnt);
+        if (pwdmnt)
+                mntput(pwdmnt);
+        if (altrootmnt)
+                mntput(altrootmnt);
+
+        put_namespace(namespace);
+        return 0;
+
+out:
+        put_namespace(namespace);
+        return -ENOMEM;
+}
+
+asmlinkage long sys_mount(char __user * dev_name, char __user * dir_name,
+                          char __user * type, unsigned long flags,
+                          void __user * data)
+{
+        int retval;
+        unsigned long data_page;
+        unsigned long type_page;
+        unsigned long dev_page;
+        char *dir_page;
+
+        retval = copy_mount_options (type, &type_page);
+        if (retval < 0)
+                return retval;
+
+        dir_page = getname(dir_name);
+        retval = PTR_ERR(dir_page);
+        if (IS_ERR(dir_page))
+                goto out1;
+
+        retval = copy_mount_options (dev_name, &dev_page);
+        if (retval < 0)
+                goto out2;
+
+        retval = copy_mount_options (data, &data_page);
+        if (retval < 0)
+                goto out3;
+
+        lock_kernel();
+        retval = do_mount((char*)dev_page, dir_page, (char*)type_page,
+                          flags, (void*)data_page);
+        unlock_kernel();
+        free_page(data_page);
+
+out3:
+        free_page(dev_page);
+out2:
+        putname(dir_page);
+out1:
+        free_page(type_page);
+        return retval;
+}
+
+/*
+ * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
+ * It can block. Requires the big lock held.
+ */
+void set_fs_root(struct fs_struct *fs, struct vfsmount *mnt,
+                 struct dentry *dentry)
+{
+        struct dentry *old_root;
+        struct vfsmount *old_rootmnt;
+        write_lock(&fs->lock);
+        old_root = fs->root;
+        old_rootmnt = fs->rootmnt;
+        fs->rootmnt = mntget(mnt);
+        fs->root = dget(dentry);
+        write_unlock(&fs->lock);
+        if (old_root) {
+                dput(old_root);
+                mntput(old_rootmnt);
+        }
+}
+
+/*
+ * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
+ * It can block. Requires the big lock held.
+ */
+void set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt,
+                struct dentry *dentry)
+{
+        struct dentry *old_pwd;
+        struct vfsmount *old_pwdmnt;
+
+        write_lock(&fs->lock);
+        old_pwd = fs->pwd;
+        old_pwdmnt = fs->pwdmnt;
+        fs->pwdmnt = mntget(mnt);
+        fs->pwd = dget(dentry);
+        write_unlock(&fs->lock);
+
+        if (old_pwd) {
+                dput(old_pwd);
+                mntput(old_pwdmnt);
+        }
+}
+
+static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
+{
+        struct task_struct *g, *p;
+        struct fs_struct *fs;
+
+        read_lock(&tasklist_lock);
+        do_each_thread(g, p) {
+                task_lock(p);
+                fs = p->fs;
+                if (fs) {
+                        atomic_inc(&fs->count);
+                        task_unlock(p);
+                        if (fs->root==old_nd->dentry&&fs->rootmnt==old_nd->mnt)
+                                set_fs_root(fs, new_nd->mnt, new_nd->dentry);
+                        if (fs->pwd==old_nd->dentry&&fs->pwdmnt==old_nd->mnt)
+                                set_fs_pwd(fs, new_nd->mnt, new_nd->dentry);
+                        put_fs_struct(fs);
+                } else
+                        task_unlock(p);
+        } while_each_thread(g, p);
+        read_unlock(&tasklist_lock);
+}
+
+/*
+ * pivot_root Semantics:
+ * Moves the root file system of the current process to the directory put_old,
+ * makes new_root as the new root file system of the current process, and sets
+ * root/cwd of all processes which had them on the current root to new_root.
+ *
+ * Restrictions:
+ * The new_root and put_old must be directories, and  must not be on the
+ * same file  system as the current process root. The put_old  must  be
+ * underneath new_root,  i.e. adding a non-zero number of /.. to the string
+ * pointed to by put_old must yield the same directory as new_root. No other
+ * file system may be mounted on put_old. After all, new_root is a mountpoint.
+ *
+ * Notes:
+ *  - we don't move root/cwd if they are not at the root (reason: if something
+ *    cared enough to change them, it's probably wrong to force them elsewhere)
+ *  - it's okay to pick a root that isn't the root of a file system, e.g.
+ *    /nfs/my_root where /nfs is the mount point. It must be a mountpoint,
+ *    though, so you may need to say mount --bind /nfs/my_root /nfs/my_root
+ *    first.
+ */
+
+asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *put_old)
+{
+        struct vfsmount *tmp;
+        struct nameidata new_nd, old_nd, parent_nd, root_parent, user_nd;
+        int error;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        lock_kernel();
+
+        error = __user_walk(new_root, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &new_nd);
+        if (error)
+                goto out0;
+        error = -EINVAL;
+        if (!check_mnt(new_nd.mnt))
+                goto out1;
+
+        error = __user_walk(put_old, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &old_nd);
+        if (error)
+                goto out1;
+
+        error = security_sb_pivotroot(&old_nd, &new_nd);
+        if (error) {
+                path_release(&old_nd);
+                goto out1;
+        }
+
+        read_lock(&current->fs->lock);
+        user_nd.mnt = mntget(current->fs->rootmnt);
+        user_nd.dentry = dget(current->fs->root);
+        read_unlock(&current->fs->lock);
+        down_write(&current->namespace->sem);
+        down(&old_nd.dentry->d_inode->i_sem);
+        error = -EINVAL;
+        if (!check_mnt(user_nd.mnt))
+                goto out2;
+        error = -ENOENT;
+        if (IS_DEADDIR(new_nd.dentry->d_inode))
+                goto out2;
+        if (d_unhashed(new_nd.dentry) && !IS_ROOT(new_nd.dentry))
+                goto out2;
+        if (d_unhashed(old_nd.dentry) && !IS_ROOT(old_nd.dentry))
+                goto out2;
+        error = -EBUSY;
+        if (new_nd.mnt == user_nd.mnt || old_nd.mnt == user_nd.mnt)
+                goto out2; /* loop, on the same file system  */
+        error = -EINVAL;
+        if (user_nd.mnt->mnt_root != user_nd.dentry)
+                goto out2; /* not a mountpoint */
+        if (new_nd.mnt->mnt_root != new_nd.dentry)
+                goto out2; /* not a mountpoint */
+        tmp = old_nd.mnt; /* make sure we can reach put_old from new_root */
+        spin_lock(&vfsmount_lock);
+        if (tmp != new_nd.mnt) {
+                for (;;) {
+                        if (tmp->mnt_parent == tmp)
+                                goto out3; /* already mounted on put_old */
+                        if (tmp->mnt_parent == new_nd.mnt)
+                                break;
+                        tmp = tmp->mnt_parent;
+                }
+                if (!is_subdir(tmp->mnt_mountpoint, new_nd.dentry))
+                        goto out3;
+        } else if (!is_subdir(old_nd.dentry, new_nd.dentry))
+                goto out3;
+        detach_mnt(new_nd.mnt, &parent_nd);
+        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 / */
+        spin_unlock(&vfsmount_lock);
+        chroot_fs_refs(&user_nd, &new_nd);
+        security_sb_post_pivotroot(&user_nd, &new_nd);
+        error = 0;
+        path_release(&root_parent);
+        path_release(&parent_nd);
+out2:
+        up(&old_nd.dentry->d_inode->i_sem);
+        up_write(&current->namespace->sem);
+        path_release(&user_nd);
+        path_release(&old_nd);
+out1:
+        path_release(&new_nd);
+out0:
+        unlock_kernel();
+        return error;
+out3:
+        spin_unlock(&vfsmount_lock);
+        goto out2;
+}
+
+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))
+                panic("Can't create rootfs");
+        namespace = kmalloc(sizeof(*namespace), GFP_KERNEL);
+        if (!namespace)
+                panic("Can't allocate initial namespace");
+        atomic_set(&namespace->count, 1);
+        INIT_LIST_HEAD(&namespace->list);
+        init_rwsem(&namespace->sem);
+        list_add(&mnt->mnt_list, &namespace->list);
+        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);
+
+        set_fs_pwd(current->fs, namespace->root, namespace->root->mnt_root);
+        set_fs_root(current->fs, namespace->root, namespace->root->mnt_root);
+}
+
+void __init mnt_init(unsigned long mempages)
+{
+        struct list_head *d;
+        unsigned int nr_hash;
+        int i;
+
+        mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct vfsmount),
+                        0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+
+        mount_hashtable = (struct list_head *)
+                __get_free_page(GFP_ATOMIC);
+
+        if (!mount_hashtable)
+                panic("Failed to allocate mount hash table\n");
+
+        /*
+         * Find the power-of-two list-heads that can fit into the allocation..
+         * We don't guarantee that "sizeof(struct list_head)" is necessarily
+         * a power-of-two.
+         */
+        nr_hash = PAGE_SIZE / sizeof(struct list_head);
+        hash_bits = 0;
+        do {
+                hash_bits++;
+        } while ((nr_hash >> hash_bits) != 0);
+        hash_bits--;
+
+        /*
+         * Re-calculate the actual number of entries and the mask
+         * from the number of bits we can fit.
+         */
+        nr_hash = 1UL << hash_bits;
+        hash_mask = nr_hash-1;
+
+        printk("Mount-cache hash table entries: %d\n", nr_hash);
+
+        /* And initialize the newly allocated array */
+        d = mount_hashtable;
+        i = nr_hash;
+        do {
+                INIT_LIST_HEAD(d);
+                d++;
+                i--;
+        } while (i);
+        sysfs_init();
+        init_rootfs();
+        init_mount_tree();
+}
+
+void __put_namespace(struct namespace *namespace)
+{
+        struct vfsmount *mnt;
+
+        down_write(&namespace->sem);
+        spin_lock(&vfsmount_lock);
+
+        list_for_each_entry(mnt, &namespace->list, mnt_list) {
+                mnt->mnt_namespace = NULL;
+        }
+
+        umount_tree(namespace->root);
+        spin_unlock(&vfsmount_lock);
+        up_write(&namespace->sem);
+        kfree(namespace);
+}