1 files changed, 20 insertions, 8 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 98d27da43304..a7f91265ea67 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -695,9 +695,6 @@ static struct mountpoint *lookup_mountpoint(struct dentry *dentry)
 
 	hlist_for_each_entry(mp, chain, m_hash) {
 		if (mp->m_dentry == dentry) {
-			/* might be worth a WARN_ON() */
-			if (d_unlinked(dentry))
-				return ERR_PTR(-ENOENT);
 			mp->m_count++;
 			return mp;
 		}
@@ -711,6 +708,9 @@ static struct mountpoint *get_mountpoint(struct dentry *dentry)
 	int ret;
 
 	if (d_mountpoint(dentry)) {
+		/* might be worth a WARN_ON() */
+		if (d_unlinked(dentry))
+			return ERR_PTR(-ENOENT);
 mountpoint:
 		read_seqlock_excl(&mount_lock);
 		mp = lookup_mountpoint(dentry);
@@ -1540,8 +1540,13 @@ static int do_umount(struct mount *mnt, int flags)
 
 	namespace_lock();
 	lock_mount_hash();
-	event++;
 
+	/* Recheck MNT_LOCKED with the locks held */
+	retval = -EINVAL;
+	if (mnt->mnt.mnt_flags & MNT_LOCKED)
+		goto out;
+
+	event++;
 	if (flags & MNT_DETACH) {
 		if (!list_empty(&mnt->mnt_list))
 			umount_tree(mnt, UMOUNT_PROPAGATE);
@@ -1555,6 +1560,7 @@ static int do_umount(struct mount *mnt, int flags)
 			retval = 0;
 		}
 	}
+out:
 	unlock_mount_hash();
 	namespace_unlock();
 	return retval;
@@ -1645,7 +1651,7 @@ int ksys_umount(char __user *name, int flags)
 		goto dput_and_out;
 	if (!check_mnt(mnt))
 		goto dput_and_out;
-	if (mnt->mnt.mnt_flags & MNT_LOCKED)
+	if (mnt->mnt.mnt_flags & MNT_LOCKED) /* Check optimistically */
 		goto dput_and_out;
 	retval = -EPERM;
 	if (flags & MNT_FORCE && !capable(CAP_SYS_ADMIN))
@@ -1728,8 +1734,14 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
 		for (s = r; s; s = next_mnt(s, r)) {
 			if (!(flag & CL_COPY_UNBINDABLE) &&
 			    IS_MNT_UNBINDABLE(s)) {
-				s = skip_mnt_tree(s);
-				continue;
+				if (s->mnt.mnt_flags & MNT_LOCKED) {
+					/* Both unbindable and locked. */
+					q = ERR_PTR(-EPERM);
+					goto out;
+				} else {
+					s = skip_mnt_tree(s);
+					continue;
+				}
 			}
 			if (!(flag & CL_COPY_MNT_NS_FILE) &&
 			    is_mnt_ns_file(s->mnt.mnt_root)) {
@@ -1782,7 +1794,7 @@ void drop_collected_mounts(struct vfsmount *mnt)
 {
 	namespace_lock();
 	lock_mount_hash();
-	umount_tree(real_mount(mnt), UMOUNT_SYNC);
+	umount_tree(real_mount(mnt), 0);
 	unlock_mount_hash();
 	namespace_unlock();
 }