X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=fs%2Fnamespace.c;h=c1fcd7434a3d81cfaed4e809756a913e5fa7842e;hb=8e8ece46a861c84343256819eaec77e608ff9217;hp=fb0a3ab5893dee184e57bfa63040bd8f315d7655;hpb=5273a3df6485dc2ad6aa7ddd441b9a21970f003b;p=linux-2.6.git

diff --git a/fs/namespace.c b/fs/namespace.c
index fb0a3ab58..c1fcd7434 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -9,6 +9,7 @@
  */
 
 #include <linux/config.h>
+#include <linux/syscalls.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/smp_lock.h>
@@ -21,7 +22,11 @@
 #include <linux/namei.h>
 #include <linux/security.h>
 #include <linux/mount.h>
+#include <linux/vserver/namespace.h>
+#include <linux/vserver/xid.h>
+
 #include <asm/uaccess.h>
+#include <asm/unistd.h>
 
 extern int __init init_rootfs(void);
 
@@ -35,7 +40,8 @@ static inline int sysfs_init(void)
 #endif
 
 /* spinlock for vfsmount related operations, inplace of dcache_lock */
-spinlock_t vfsmount_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
+ __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; 
@@ -58,6 +64,7 @@ struct vfsmount *alloc_vfsmnt(const char *name)
 		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);
@@ -102,15 +109,9 @@ struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
 	return found;
 }
 
-EXPORT_SYMBOL(lookup_mnt);
-
-static int check_mnt(struct vfsmount *mnt)
+static inline int check_mnt(struct vfsmount *mnt)
 {
-	spin_lock(&vfsmount_lock);
-	while (mnt->mnt_parent != mnt)
-		mnt = mnt->mnt_parent;
-	spin_unlock(&vfsmount_lock);
-	return mnt == current->namespace->root;
+	return mnt->mnt_namespace == current->namespace;
 }
 
 static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd)
@@ -162,6 +163,15 @@ clone_mnt(struct vfsmount *old, struct dentry *root)
 		mnt->mnt_root = dget(root);
 		mnt->mnt_mountpoint = mnt->mnt_root;
 		mnt->mnt_parent = mnt;
+		mnt->mnt_namespace = old->mnt_namespace;
+		mnt->mnt_xid = old->mnt_xid;
+
+		/* 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;
 }
@@ -209,6 +219,34 @@ static inline void mangle(struct seq_file *m, const char *s)
 	seq_escape(m, s, " \t\n\\");
 }
 
+static int mnt_is_reachable(struct vfsmount *mnt)
+{
+	struct vfsmount *root_mnt;
+	struct dentry *root, *point;
+	int ret;
+
+	if (!mnt)
+		return 1;
+	if (mnt == mnt->mnt_namespace->root)
+		return 1;
+
+	spin_lock(&dcache_lock);
+	root_mnt = current->fs->rootmnt;
+	root = current->fs->root;
+	point = root;
+
+	while ((mnt != mnt->mnt_parent) && (mnt != root_mnt)) {
+		point = mnt->mnt_mountpoint;
+		mnt = mnt->mnt_parent;
+	}
+
+	ret = (mnt == root_mnt) && is_subdir(point, root);
+
+	spin_unlock(&dcache_lock);
+
+	return ret;
+}
+
 static int show_vfsmnt(struct seq_file *m, void *v)
 {
 	struct vfsmount *mnt = v;
@@ -222,6 +260,7 @@ static int show_vfsmnt(struct seq_file *m, void *v)
 		{ MS_MANDLOCK, ",mand" },
 		{ MS_NOATIME, ",noatime" },
 		{ MS_NODIRATIME, ",nodiratime" },
+		{ MS_TAGXID, ",tagxid" },
 		{ 0, NULL }
 	};
 	static struct proc_fs_info mnt_info[] = {
@@ -230,12 +269,25 @@ static int show_vfsmnt(struct seq_file *m, void *v)
 		{ MNT_NOEXEC, ",noexec" },
 		{ 0, NULL }
 	};
+
 	struct proc_fs_info *fs_infop;
+	unsigned long s_flags = mnt->mnt_sb->s_flags;
+	int mnt_flags = mnt->mnt_flags;
 
-	mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
-	seq_putc(m, ' ');
-	seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
-	seq_putc(m, ' ');
+	if (vx_flags(VXF_HIDE_MOUNT, 0))
+		return 0;
+	if (!mnt_is_reachable(mnt))
+		return 0;
+
+	if (!vx_check(0, VX_ADMIN|VX_WATCH) &&
+		mnt == current->fs->rootmnt) {
+		seq_puts(m, "/dev/root / ");
+	} else {
+		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++) {
@@ -246,6 +298,8 @@ static int show_vfsmnt(struct seq_file *m, void *v)
 		if (mnt->mnt_flags & fs_infop->flag)
 			seq_puts(m, fs_infop->str);
 	}
+	if (mnt->mnt_flags & MNT_XID)
+		seq_printf(m, ",xid=%d", mnt->mnt_xid);
 	if (mnt->mnt_sb->s_op->show_options)
 		err = mnt->mnt_sb->s_op->show_options(m, mnt);
 	seq_puts(m, " 0 0\n");
@@ -259,7 +313,65 @@ struct seq_operations mounts_op = {
 	.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.
@@ -273,19 +385,14 @@ int may_umount(struct vfsmount *mnt)
 
 EXPORT_SYMBOL(may_umount);
 
-void umount_tree(struct vfsmount *mnt)
+static inline void __umount_list(struct list_head *kill)
 {
-	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);
-	}
+	struct vfsmount *mnt;
 
-	while (!list_empty(&kill)) {
-		mnt = list_entry(kill.next, struct vfsmount, mnt_list);
+	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 {
@@ -299,6 +406,32 @@ void umount_tree(struct vfsmount *mnt)
 	}
 }
 
+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);
+	}
+	__umount_list(&kill);
+}
+
+void umount_unused(struct vfsmount *mnt, struct fs_struct *fs)
+{
+	struct vfsmount *p;
+	LIST_HEAD(kill);
+
+	for (p = mnt; p; p = next_mnt(p, mnt)) {
+		if (p == fs->rootmnt || p == fs->pwdmnt)
+			continue;
+		list_del(&p->mnt_list);
+		list_add(&p->mnt_list, &kill);
+	}
+	__umount_list(&kill);
+}
+
 static int do_umount(struct vfsmount *mnt, int flags)
 {
 	struct super_block * sb = mnt->mnt_sb;
@@ -308,6 +441,24 @@ static int do_umount(struct vfsmount *mnt, int 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
@@ -340,7 +491,8 @@ static int do_umount(struct vfsmount *mnt, int flags)
 		down_write(&sb->s_umount);
 		if (!(sb->s_flags & MS_RDONLY)) {
 			lock_kernel();
-			retval = do_remount_sb(sb, MS_RDONLY, 0, 0);
+			DQUOT_OFF(sb);
+			retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
 			unlock_kernel();
 		}
 		up_write(&sb->s_umount);
@@ -396,16 +548,18 @@ asmlinkage long sys_umount(char __user * name, int flags)
 		goto dput_and_out;
 
 	retval = -EPERM;
-	if (!capable(CAP_SYS_ADMIN))
+	if (!capable(CAP_SYS_ADMIN) && !vx_ccaps(VXC_SECURE_MOUNT))
 		goto dput_and_out;
 
 	retval = do_umount(nd.mnt, flags);
 dput_and_out:
-	path_release(&nd);
+	path_release_on_umount(&nd);
 out:
 	return retval;
 }
 
+#ifdef __ARCH_WANT_SYS_OLDUMOUNT
+
 /*
  *	The 2.0 compatible umount. No flags. 
  */
@@ -415,10 +569,14 @@ 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;
+	if (vx_ccaps(VXC_SECURE_MOUNT))
+		return 0;
 	return -EPERM;
 #ifdef notyet
 	if (S_ISLNK(nd->dentry->d_inode->i_mode))
@@ -530,11 +688,12 @@ out_unlock:
 /*
  * do loopback mount.
  */
-static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
+static int do_loopback(struct nameidata *nd, char *old_name, xid_t xid, int flags)
 {
 	struct nameidata old_nd;
 	struct vfsmount *mnt = NULL;
 	int err = mount_is_safe(nd);
+	int recurse = flags & MS_REC;
 	if (err)
 		return err;
 	if (!old_name || !*old_name)
@@ -554,6 +713,15 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
 	}
 
 	if (mnt) {
+		/* stop bind mounts from expiring */
+		spin_lock(&vfsmount_lock);
+		list_del_init(&mnt->mnt_fslink);
+		spin_unlock(&vfsmount_lock);
+
+		if (flags & MS_XID) {
+			mnt->mnt_xid = xid;
+			mnt->mnt_flags |= MNT_XID;
+		}
 		err = graft_tree(mnt, nd);
 		if (err) {
 			spin_lock(&vfsmount_lock);
@@ -574,12 +742,13 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
  * on it - tough luck.
  */
 
-static int do_remount(struct nameidata *nd,int flags,int mnt_flags,void *data)
+static int do_remount(struct nameidata *nd, int flags, int mnt_flags,
+		      void *data, xid_t xid)
 {
 	int err;
 	struct super_block * sb = nd->mnt->mnt_sb;
 
-	if (!capable(CAP_SYS_ADMIN))
+	if (!capable(CAP_SYS_ADMIN) && !vx_ccaps(VXC_SECURE_REMOUNT))
 		return -EPERM;
 
 	if (!check_mnt(nd->mnt))
@@ -588,10 +757,15 @@ static int do_remount(struct nameidata *nd,int flags,int mnt_flags,void *data)
 	if (nd->dentry != nd->mnt->mnt_root)
 		return -EINVAL;
 
+	if (vx_ccaps(VXC_SECURE_REMOUNT))
+		mnt_flags |= MNT_NODEV;
 	down_write(&sb->s_umount);
 	err = do_remount_sb(sb, flags, data, 0);
-	if (!err)
+	if (!err) {
 		nd->mnt->mnt_flags=mnt_flags;
+		if (flags & MS_XID)
+			nd->mnt->mnt_xid = xid;
+	}
 	up_write(&sb->s_umount);
 	if (!err)
 		security_sb_post_remount(nd->mnt, flags, data);
@@ -603,7 +777,7 @@ 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))
+	if (!capable(CAP_SYS_ADMIN) && !vx_ccaps(VXC_SECURE_MOUNT))
 		return -EPERM;
 	if (!old_name || !*old_name)
 		return -EINVAL;
@@ -646,6 +820,10 @@ static int do_move_mount(struct nameidata *nd, char *old_name)
 
 	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:
@@ -658,23 +836,37 @@ out:
 	return err;
 }
 
-static int do_add_mount(struct nameidata *nd, char *type, int flags,
+/*
+ * 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;
-	int err;
 
 	if (!type || !memchr(type, 0, PAGE_SIZE))
 		return -EINVAL;
 
 	/* we need capabilities... */
-	if (!capable(CAP_SYS_ADMIN))
+	if (!capable(CAP_SYS_ADMIN) && !vx_ccaps(VXC_SECURE_MOUNT))
 		return -EPERM;
 
 	mnt = do_kern_mount(type, flags, name, data);
-	err = PTR_ERR(mnt);
 	if (IS_ERR(mnt))
-		goto out;
+		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 */
@@ -686,23 +878,167 @@ static int do_add_mount(struct nameidata *nd, char *type, int flags,
 
 	/* Refuse the same filesystem on the same mount point */
 	err = -EBUSY;
-	if (nd->mnt->mnt_sb == mnt->mnt_sb && nd->mnt->mnt_root == nd->dentry)
+	if (nd->mnt->mnt_sb == newmnt->mnt_sb &&
+	    nd->mnt->mnt_root == nd->dentry)
 		goto unlock;
 
 	err = -EINVAL;
-	if (S_ISLNK(mnt->mnt_root->d_inode->i_mode))
+	if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode))
 		goto unlock;
 
-	mnt->mnt_flags = mnt_flags;
-	err = graft_tree(mnt, nd);
+	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(mnt);
-out:
+	mntput(newmnt);
 	return err;
 }
 
-int copy_mount_options (const void __user *data, unsigned long *where)
+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;
@@ -724,7 +1060,7 @@ int copy_mount_options (const void __user *data, unsigned long *where)
 	if (size > PAGE_SIZE)
 		size = PAGE_SIZE;
 
-	i = size - copy_from_user((void *)page, data, size);
+	i = size - exact_copy_from_user((void *)page, data, size);
 	if (!i) {
 		free_page(page); 
 		return -EFAULT;
@@ -755,6 +1091,7 @@ long do_mount(char * dev_name, char * dir_name, char *type_page,
 	struct nameidata nd;
 	int retval = 0;
 	int mnt_flags = 0;
+	xid_t xid = 0;
 
 	/* Discard magic */
 	if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
@@ -770,6 +1107,14 @@ long do_mount(char * dev_name, char * dir_name, char *type_page,
 	if (data_page)
 		((char *)data_page)[PAGE_SIZE - 1] = 0;
 
+	retval = vx_parse_xid(data_page, &xid, 1);
+	if (retval) {
+		mnt_flags |= MNT_XID;
+		/* bind and re-mounts get xid flag */
+		if (flags & (MS_BIND|MS_REMOUNT))
+			flags |= MS_XID;
+	}
+
 	/* Separate the per-mountpoint flags */
 	if (flags & MS_NOSUID)
 		mnt_flags |= MNT_NOSUID;
@@ -779,6 +1124,9 @@ long do_mount(char * dev_name, char * dir_name, char *type_page,
 		mnt_flags |= MNT_NOEXEC;
 	flags &= ~(MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_ACTIVE);
 
+	if (vx_ccaps(VXC_SECURE_MOUNT))
+		mnt_flags |= MNT_NODEV;
+
 	/* ... and get the mountpoint */
 	retval = path_lookup(dir_name, LOOKUP_FOLLOW, &nd);
 	if (retval)
@@ -790,13 +1138,13 @@ long do_mount(char * dev_name, char * dir_name, char *type_page,
 
 	if (flags & MS_REMOUNT)
 		retval = do_remount(&nd, flags & ~MS_REMOUNT, mnt_flags,
-				    data_page);
+				    data_page, xid);
 	else if (flags & MS_BIND)
-		retval = do_loopback(&nd, dev_name, flags & MS_REC);
+		retval = do_loopback(&nd, dev_name, xid, flags);
 	else if (flags & MS_MOVE)
 		retval = do_move_mount(&nd, dev_name);
 	else
-		retval = do_add_mount(&nd, type_page, flags, mnt_flags,
+		retval = do_new_mount(&nd, type_page, flags, mnt_flags,
 				      dev_name, data_page);
 dput_out:
 	path_release(&nd);
@@ -809,6 +1157,7 @@ int copy_namespace(int flags, struct task_struct *tsk)
 	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;
@@ -818,7 +1167,7 @@ int copy_namespace(int flags, struct task_struct *tsk)
 	if (!(flags & CLONE_NEWNS))
 		return 0;
 
-	if (!capable(CAP_SYS_ADMIN)) {
+	if (!capable(CAP_SYS_ADMIN) && !vx_ccaps(VXC_SECURE_MOUNT)) {
 		put_namespace(namespace);
 		return -EPERM;
 	}
@@ -843,14 +1192,16 @@ int copy_namespace(int flags, struct task_struct *tsk)
 	list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
 	spin_unlock(&vfsmount_lock);
 
-	/* Second pass: switch the tsk->fs->* elements */
-	if (fs) {
-		struct vfsmount *p, *q;
-		write_lock(&fs->lock);
-
-		p = namespace->root;
-		q = new_ns->root;
-		while (p) {
+	/*
+	 * 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);
@@ -863,10 +1214,9 @@ int copy_namespace(int flags, struct task_struct *tsk)
 				altrootmnt = p;
 				fs->altrootmnt = mntget(q);
 			}
-			p = next_mnt(p, namespace->root);
-			q = next_mnt(q, new_ns->root);
 		}
-		write_unlock(&fs->lock);
+		p = next_mnt(p, namespace->root);
+		q = next_mnt(q, new_ns->root);
 	}
 	up_write(&tsk->namespace->sem);
 
@@ -950,8 +1300,6 @@ void set_fs_root(struct fs_struct *fs, struct vfsmount *mnt,
 	}
 }
 
-EXPORT_SYMBOL(set_fs_root);
-
 /*
  * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
  * It can block. Requires the big lock held.
@@ -975,8 +1323,6 @@ void set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt,
 	}
 }
 
-EXPORT_SYMBOL(set_fs_pwd);
-
 static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
 {
 	struct task_struct *g, *p;
@@ -1121,6 +1467,7 @@ static void __init init_mount_tree(void)
 	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);
@@ -1142,9 +1489,7 @@ void __init mnt_init(unsigned long mempages)
 	int i;
 
 	mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct vfsmount),
-					0, SLAB_HWCACHE_ALIGN, NULL, NULL);
-	if (!mnt_cache)
-		panic("Cannot create vfsmount cache");
+			0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
 
 	order = 0; 
 	mount_hashtable = (struct list_head *)
@@ -1190,8 +1535,15 @@ void __init mnt_init(unsigned long mempages)
 
 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);