--- a/mercurial/localrepo.py	Thu Jul 13 09:51:50 2017 -0700
+++ b/mercurial/localrepo.py	Wed Jul 12 15:24:07 2017 -0700
@@ -1202,7 +1202,7 @@
             else:
                 # discard all changes (including ones already written
                 # out) in this transaction
-                repo.dirstate.restorebackup(None, prefix='journal.')
+                repo.dirstate.restorebackup(None, 'journal.dirstate')
 
                 repo.invalidate(clearfilecache=True)
 
@@ -1262,7 +1262,7 @@
 
     @unfilteredmethod
     def _writejournal(self, desc):
-        self.dirstate.savebackup(None, prefix='journal.')
+        self.dirstate.savebackup(None, 'journal.dirstate')
         self.vfs.write("journal.branch",
                           encoding.fromlocal(self.dirstate.branch()))
         self.vfs.write("journal.desc",
@@ -1350,7 +1350,7 @@
             # prevent dirstateguard from overwriting already restored one
             dsguard.close()
 
-            self.dirstate.restorebackup(None, prefix='undo.')
+            self.dirstate.restorebackup(None, 'undo.dirstate')
             try:
                 branch = self.vfs.read('undo.branch')
                 self.dirstate.setbranch(encoding.tolocal(branch))