diff --git a/mercurial/dirstate.py b/mercurial/dirstate.py
--- a/mercurial/dirstate.py
+++ b/mercurial/dirstate.py
@@ -733,20 +733,11 @@
 
         filename = self._filename
         if tr:
-            # 'dirstate.write()' is not only for writing in-memory
-            # changes out, but also for dropping ambiguous timestamp.
-            # delayed writing re-raise "ambiguous timestamp issue".
-            # See also the wiki page below for detail:
-            # https://www.mercurial-scm.org/wiki/DirstateTransactionPlan
-
-            # record when mtime start to be ambiguous
-            now = timestamp.get_fs_now(self._opener)
-
             # delay writing in-memory changes out
             tr.addfilegenerator(
                 b'dirstate',
                 (self._filename,),
-                lambda f: self._writedirstate(tr, f, now=now),
+                lambda f: self._writedirstate(tr, f),
                 location=b'plain',
             )
             return
@@ -765,7 +756,7 @@
         """
         self._plchangecallbacks[category] = callback
 
-    def _writedirstate(self, tr, st, now=None):
+    def _writedirstate(self, tr, st):
         # notify callbacks about parents change
         if self._origpl is not None and self._origpl != self._pl:
             for c, callback in sorted(
@@ -774,12 +765,7 @@
                 callback(self, self._origpl, self._pl)
             self._origpl = None
 
-        if now is None:
-            # use the modification time of the newly created temporary file as the
-            # filesystem's notion of 'now'
-            now = timestamp.mtime_of(util.fstat(st))
-
-        self._map.write(tr, st, now)
+        self._map.write(tr, st)
         self._dirty = False
 
     def _dirignore(self, f):
diff --git a/mercurial/dirstatemap.py b/mercurial/dirstatemap.py
--- a/mercurial/dirstatemap.py
+++ b/mercurial/dirstatemap.py
@@ -444,7 +444,7 @@
         self.__getitem__ = self._map.__getitem__
         self.get = self._map.get
 
-    def write(self, tr, st, now):
+    def write(self, tr, st):
         if self._use_dirstate_v2:
             packed, meta = v2.pack_dirstate(self._map, self.copymap)
             self.write_v2_no_append(tr, st, meta, packed)
@@ -655,7 +655,7 @@
             self._map
             return self.identity
 
-        def write(self, tr, st, now):
+        def write(self, tr, st):
             if not self._use_dirstate_v2:
                 p1, p2 = self.parents()
                 packed = self._map.write_v1(p1, p2)