fixes #1977

app/models/wiki_page.rb

@@ -9,6 +9,7 @@ class WikiPage < ActiveRecord::Base
   validates_uniqueness_of :title, :case_sensitive => false
   validates_presence_of :title
   validate :validate_locker_is_janitor
+  validate :validate_not_locked
   attr_accessible :title, :body, :is_locked
   has_one :tag, :foreign_key => "name", :primary_key => "title"
   has_one :artist, :foreign_key => "name", :primary_key => "title", :conditions => {:is_active => true}
@@ -101,6 +102,13 @@ class WikiPage < ActiveRecord::Base
     end
   end
 
+  def validate_not_locked
+    if is_locked? && !CurrentUser.is_janitor?
+      errors.add(:is_locked, "and cannot be updated")
+      return false
+    end
+  end
+
   def revert_to(version)
     self.title = version.title
     self.body = version.body