---
 fs/ext4/namei.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1031,6 +1031,16 @@ errout:
 	return NULL;
 }
 
+static inline int
+is_dot_or_dot_dot(const struct qstr *name)
+{
+	if (name->name[0] != '.')
+		return 0;
+	if (name->len == 1 || (name->len == 2 && name->name[1] == '.'))
+		return 1;
+	return 0;
+}
+
 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 {
 	struct inode *inode;
@@ -1061,6 +1071,38 @@ static struct dentry *ext4_lookup(struct
 			}
 		}
 	}
+
+	/* ".." shouldn't go into dcache to preserve dcache hierarchy
+	 * otherwise we'll get parent being a child of actual child.
+	 * see bug 10458 for details -bzzz */
+	if (inode && is_dot_or_dot_dot(&dentry->d_name)) {
+		struct dentry *tmp, *goal = NULL;
+		struct list_head *lp;
+
+		/* first, look for an existing dentry - any one is good */
+		spin_lock(&inode->i_lock);
+		list_for_each(lp, &inode->i_dentry) {
+			tmp = list_entry(lp, struct dentry, d_alias);
+			goal = tmp;
+			dget(goal);
+			break;
+		}
+		if (goal == NULL) {
+			/* there is no alias, we need to make current dentry:
+			 *  a) inaccessible for __d_lookup()
+			 *  b) inaccessible for iopen */
+			J_ASSERT(list_empty(&dentry->d_alias));
+			dentry->d_flags |= DCACHE_NFSFS_RENAMED;
+			/* this is d_instantiate() ... */
+			list_add(&dentry->d_alias, &inode->i_dentry);
+			dentry->d_inode = inode;
+		}
+		spin_unlock(&inode->i_lock);
+		if (goal)
+			iput(inode);
+		return goal;
+	}
+
 	return d_splice_alias(inode, dentry);
 }