diff --git a/hgext3rd/undo.py b/hgext3rd/undo.py
--- a/hgext3rd/undo.py
+++ b/hgext3rd/undo.py
@@ -13,6 +13,7 @@
     dispatch,
     error,
     extensions,
+    localrepo,
     lock as lockmod,
     registrar,
     revlog,
@@ -37,6 +38,9 @@
 def extsetup(ui):
     extensions.wrapfunction(dispatch, 'runcommand', _runcommandwrapper)
 
+    # undo has its own locking, whitelist itself to bypass repo lock audit
+    localrepo.localrepository._wlockfreeprefix.add('undolog/')
+
 # Wrappers
 
 def _runcommandwrapper(orig, lui, repo, cmd, fullargs, *args):
@@ -73,8 +77,8 @@
         # allows running command during other commands when
         # otherwise legal.  Could cause weird undolog states,
         # which gap handling generally covers.
-        with lockmod.lock(repo.vfs, "undologlock",
-                          desc="undolog"):
+        repo.vfs.makedirs('undolog')
+        with lockmod.lock(repo.vfs, "undolog/lock", desc="undolog"):
             # developer config: undo._duringundologlock
             if repo.ui.configbool('undo', '_duringundologlock'):
                 repo.hook("duringundologlock")
@@ -94,8 +98,8 @@
     # abandoned tr's (since we only record info) and doesn't
     # do any tag handling
     vfsmap = {'plain': repo.vfs}
-    tr = transaction.transaction(repo.ui.warn, repo.svfs, vfsmap,
-                                 "_undojournal", "_undolog")
+    tr = transaction.transaction(repo.ui.warn, repo.vfs, vfsmap,
+                                 "undolog/tr.journal", "undolog/tr.undo")
     return tr
 
 def log(repo, command, tr):
@@ -135,9 +139,6 @@
 def writelog(repo, tr, name, revstring):
     if tr is None:
         raise error.ProgrammingError
-    # the transaction code doesn't work with vfs
-    # specifically, repo.recover() assumes svfs?
-    repo.svfs.makedirs('undolog')
     rlog = _getrevlog(repo, name)
     node = rlog.addrevision(revstring, tr, 1, nullid, nullid)
     return hex(node)
@@ -316,4 +317,4 @@
 
 def _getrevlog(repo, filename):
     path = 'undolog/' + filename
-    return revlog.revlog(repo.svfs, path)
+    return revlog.revlog(repo.vfs, path)
diff --git a/tests/test-undo.t b/tests/test-undo.t
--- a/tests/test-undo.t
+++ b/tests/test-undo.t
@@ -23,7 +23,7 @@
   $ touch c2 && hg add c2 && hg ci -mc2
   $ hg book feature2
   $ touch d && hg add d && hg ci -md
-  $ hg debugindex .hg/store/undolog/command.i
+  $ hg debugindex .hg/undolog/command.i
      rev    offset  length  delta linkrev nodeid       p1           p2
        0         0       0     -1       1 b80de5d13875 000000000000 000000000000
        1         0      12     -1       1 440cdcef588f 000000000000 000000000000
@@ -36,27 +36,27 @@
        8        70       8     -1       1 60920018c706 000000000000 000000000000
        9        78      14     -1       1 c3e212568400 000000000000 000000000000
       10        92       7     -1       1 9d609b5b001c 000000000000 000000000000
-  $ hg debugdata .hg/store/undolog/command.i 0
-  $ hg debugdata .hg/store/undolog/command.i 1
+  $ hg debugdata .hg/undolog/command.i 0
+  $ hg debugdata .hg/undolog/command.i 1
   book\x00master (no-eol) (esc)
-  $ hg debugdata .hg/store/undolog/command.i 2
+  $ hg debugdata .hg/undolog/command.i 2
   ci\x00-ma1 (no-eol) (esc)
-  $ hg debugdata .hg/store/undolog/command.i 3
+  $ hg debugdata .hg/undolog/command.i 3
   ci\x00-ma2 (no-eol) (esc)
-  $ hg debugdata .hg/store/undolog/bookmarks.i 0
-  $ hg debugdata .hg/store/undolog/bookmarks.i 1
+  $ hg debugdata .hg/undolog/bookmarks.i 0
+  $ hg debugdata .hg/undolog/bookmarks.i 1
   master 0000000000000000000000000000000000000000 (no-eol)
-  $ hg debugdata .hg/store/undolog/bookmarks.i 2
+  $ hg debugdata .hg/undolog/bookmarks.i 2
   master df4fd610a3d6ca792281e7576587fa18f940d37a (no-eol)
-  $ hg debugdata .hg/store/undolog/workingparent.i 0
+  $ hg debugdata .hg/undolog/workingparent.i 0
   0000000000000000000000000000000000000000 (no-eol)
-  $ hg debugdata .hg/store/undolog/workingparent.i 1
+  $ hg debugdata .hg/undolog/workingparent.i 1
   df4fd610a3d6ca792281e7576587fa18f940d37a (no-eol)
-  $ hg debugdata .hg/store/undolog/draftheads.i 1
+  $ hg debugdata .hg/undolog/draftheads.i 1
   df4fd610a3d6ca792281e7576587fa18f940d37a (no-eol)
-  $ hg debugdata .hg/store/undolog/draftheads.i 2
+  $ hg debugdata .hg/undolog/draftheads.i 2
   b68836a6e2cac33ba33a20249b85a486eec78186 (no-eol)
-  $ hg debugdata .hg/store/undolog/index.i 1
+  $ hg debugdata .hg/undolog/index.i 1
   bookmarks 8153d44860d076e9c328951c8f36cf8daebe695a
   command 440cdcef588f9a594c5530a5b6dede39a96d930d
   date * (glob)
@@ -65,7 +65,7 @@
   $ touch a3 && hg add a3
   $ hg commit --amend
   saved backup bundle to $TESTTMP/repo/.hg/strip-backup/db92053d5c83-e25f6bc1-amend.hg (glob)
-  $ hg debugdata .hg/store/undolog/command.i 11
+  $ hg debugdata .hg/undolog/command.i 11
   commit\x00--amend (no-eol) (esc)
 
 Test debugundohistory