From: Miklos Szeredi <mszeredi@suse.cz>
Allow clone_mnt() to return errors other than ENOMEM.  This will be used for

returning a different error value when the number of user mounts goes over the

limit.
Fix copy_tree() to return EPERM for unbindable mounts.
Don't propagate further from dup_mnt_ns() as that copy_tree() can only fail

with -ENOMEM.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

---
Index: linux/fs/namespace.c

===================================================================

--- linux.orig/fs/namespace.c	2007-04-26 13:17:13.000000000 +0200

+++ linux/fs/namespace.c	2007-04-26 13:18:46.000000000 +0200

@@ -262,41 +262,42 @@ static struct vfsmount *clone_mnt(struct

 	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;

-

-		/* don't copy the MNT_USER flag */

-		mnt->mnt_flags &= ~MNT_USER;

-		if (flag & CL_SETUSER)

-			set_mnt_user(mnt);

-

-		if (flag & CL_SLAVE) {

-			list_add(&mnt->mnt_slave, &old->mnt_slave_list);

-			mnt->mnt_master = old;

-			CLEAR_MNT_SHARED(mnt);

-		} else {

-			if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old))

-				list_add(&mnt->mnt_share, &old->mnt_share);

-			if (IS_MNT_SLAVE(old))

-				list_add(&mnt->mnt_slave, &old->mnt_slave);

-			mnt->mnt_master = old->mnt_master;

-		}

-		if (flag & CL_MAKE_SHARED)

-			set_mnt_shared(mnt);

+	if (!mnt)

+		return ERR_PTR(-ENOMEM);
-		/* stick the duplicate mount on the same expiry list

-		 * as the original if that was on one */

-		if (flag & CL_EXPIRE) {

-			spin_lock(&vfsmount_lock);

-			if (!list_empty(&old->mnt_expire))

-				list_add(&mnt->mnt_expire, &old->mnt_expire);

-			spin_unlock(&...
[ message continues ]