fs: remove Inode.Parents

The API is poorly thought out, as a node can be child in multiple
parents with the same name. Similary, a reversing keys and values is
not possible. A child may have the same parent with different names.

Change-Id: I3888606016b56f06d80ef56ebc7b8725a819c1a9

fs/inode.go

@@ -483,18 +483,6 @@ func (n *Inode) Children() map[string]*Inode {
 	return r
 }
 
-// Parents returns the parents of this Inode, along with the name
-// with which they're are a child
-func (n *Inode) Parents() map[string]*Inode {
-	n.mu.Lock()
-	defer n.mu.Unlock()
-	r := make(map[string]*Inode, len(n.parents))
-	for k := range n.parents {
-		r[k.name] = k.parent
-	}
-	return r
-}
-
 // Parents returns a parent of this Inode, or nil if this Inode is
 // deleted or is the root
 func (n *Inode) Parent() (string, *Inode) {