diff --git a/mercurial/changelog.py b/mercurial/changelog.py
--- a/mercurial/changelog.py
+++ b/mercurial/changelog.py
@@ -77,6 +77,13 @@
     ]
     return "\0".join(items)
 
+def encodecopies(copies):
+    items = [
+        '%s\0%s' % (_string_escape(k), _string_escape(copies[k]))
+        for k in sorted(copies)
+    ]
+    return "\n".join(items)
+
 def stripdesc(desc):
     """strip trailing whitespace and leading and trailing empty lines"""
     return '\n'.join([l.rstrip() for l in desc.splitlines()]).strip('\n')
@@ -530,7 +537,7 @@
         return l[3:]
 
     def add(self, manifest, files, desc, transaction, p1, p2,
-                  user, date=None, extra=None):
+                  user, date=None, extra=None, p1copies=None, p2copies=None):
         # Convert to UTF-8 encoded bytestrings as the very first
         # thing: calling any method on a localstr object will turn it
         # into a str object and the cached UTF-8 string is thus lost.
@@ -559,6 +566,13 @@
             elif branch in (".", "null", "tip"):
                 raise error.StorageError(_('the name \'%s\' is reserved')
                                          % branch)
+        if (p1copies or p2copies) and extra is None:
+            extra = {}
+        if p1copies:
+            extra['p1copies'] = encodecopies(p1copies)
+        if p2copies:
+            extra['p2copies'] = encodecopies(p2copies)
+
         if extra:
             extra = encodeextra(extra)
             parseddate = "%s %s" % (parseddate, extra)
diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -488,6 +488,9 @@
 coreconfigitem('experimental', 'copies.read-from',
     default="filelog-only",
 )
+coreconfigitem('experimental', 'copies.write-to',
+    default='filelog-only',
+)
 coreconfigitem('experimental', 'crecordtest',
     default=None,
 )
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -2303,7 +2303,8 @@
         """Returns the wlock if it's held, or None if it's not."""
         return self._currentlock(self._wlockref)
 
-    def _filecommit(self, fctx, manifest1, manifest2, linkrev, tr, changelist):
+    def _filecommit(self, fctx, manifest1, manifest2, linkrev, tr, changelist,
+                    includecopymeta):
         """
         commit an individual file as part of a larger transaction
         """
@@ -2362,8 +2363,9 @@
 
             if cnode:
                 self.ui.debug(" %s: copy %s:%s\n" % (fname, cfname, hex(cnode)))
-                meta["copy"] = cfname
-                meta["copyrev"] = hex(cnode)
+                if includecopymeta:
+                    meta["copy"] = cfname
+                    meta["copyrev"] = hex(cnode)
                 fparent1, fparent2 = nullid, newfparent
             else:
                 self.ui.warn(_("warning: can't find ancestor for '%s' "
@@ -2531,6 +2533,12 @@
         p1, p2 = ctx.p1(), ctx.p2()
         user = ctx.user()
 
+        writecopiesto = self.ui.config('experimental', 'copies.write-to')
+        writefilecopymeta = writecopiesto != 'changeset-only'
+        p1copies, p2copies = None, None
+        if writecopiesto in ('changeset-only', 'compatibility'):
+            p1copies = ctx.p1copies()
+            p2copies = ctx.p2copies()
         with self.lock(), self.transaction("commit") as tr:
             trp = weakref.proxy(tr)
 
@@ -2564,7 +2572,8 @@
                         else:
                             added.append(f)
                             m[f] = self._filecommit(fctx, m1, m2, linkrev,
-                                                    trp, changed)
+                                                    trp, changed,
+                                                    writefilecopymeta)
                             m.setflag(f, fctx.flags())
                     except OSError:
                         self.ui.warn(_("trouble committing %s!\n") %
@@ -2618,7 +2627,8 @@
             self.changelog.delayupdate(tr)
             n = self.changelog.add(mn, files, ctx.description(),
                                    trp, p1.node(), p2.node(),
-                                   user, ctx.date(), ctx.extra().copy())
+                                   user, ctx.date(), ctx.extra().copy(),
+                                   p1copies, p2copies)
             xp1, xp2 = p1.hex(), p2 and p2.hex() or ''
             self.hook('pretxncommit', throw=True, node=hex(n), parent1=xp1,
                       parent2=xp2)
diff --git a/tests/test-annotate.t b/tests/test-annotate.t
--- a/tests/test-annotate.t
+++ b/tests/test-annotate.t
@@ -438,7 +438,7 @@
   > def reposetup(ui, repo):
   >     class legacyrepo(repo.__class__):
   >         def _filecommit(self, fctx, manifest1, manifest2,
-  >                         linkrev, tr, changelist):
+  >                         linkrev, tr, changelist, includecopymeta):
   >             fname = fctx.path()
   >             text = fctx.data()
   >             flog = self.file(fname)
diff --git a/tests/test-copies-in-changeset.t b/tests/test-copies-in-changeset.t
new file mode 100644
--- /dev/null
+++ b/tests/test-copies-in-changeset.t
@@ -0,0 +1,105 @@
+
+  $ cat >> $HGRCPATH << EOF
+  > [experimental]
+  > copies.write-to=changeset-only
+  > [alias]
+  > changesetcopies = log -r . -T 'files: {files}
+  >   {extras % "{ifcontains("copies", key, "{key}: {value}\n")}"}'
+  > EOF
+
+Check that copies are recorded correctly
+
+  $ hg init repo
+  $ cd repo
+  $ echo a > a
+  $ hg add a
+  $ hg ci -m initial
+  $ hg cp a b
+  $ hg cp a c
+  $ hg cp a d
+  $ hg ci -m 'copy a to b, c, and d'
+  $ hg changesetcopies
+  files: b c d
+  p1copies: b\x00a (esc)
+  c\x00a (esc)
+  d\x00a (esc)
+
+Check that renames are recorded correctly
+
+  $ hg mv b b2
+  $ hg ci -m 'rename b to b2'
+  $ hg changesetcopies
+  files: b b2
+  p1copies: b2\x00b (esc)
+
+Rename onto existing file. This should get recorded in the changeset files list and in the extras,
+even though there is no filelog entry.
+
+  $ hg cp b2 c --force
+  $ hg st --copies
+  M c
+    b2
+  $ hg debugindex c
+     rev linkrev nodeid       p1           p2
+       0       1 b789fdd96dc2 000000000000 000000000000
+  $ hg ci -m 'move b onto d'
+  $ hg changesetcopies
+  files: c
+  p1copies: c\x00b2 (esc)
+  $ hg debugindex c
+     rev linkrev nodeid       p1           p2
+       0       1 b789fdd96dc2 000000000000 000000000000
+
+Create a merge commit with copying done during merge.
+
+  $ hg co 0
+  0 files updated, 0 files merged, 3 files removed, 0 files unresolved
+  $ hg cp a e
+  $ hg cp a f
+  $ hg ci -m 'copy a to e and f'
+  created new head
+  $ hg merge 3
+  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  (branch merge, don't forget to commit)
+File 'a' exists on both sides, so 'g' could be recorded as being from p1 or p2, but we currently
+always record it as being from p1
+  $ hg cp a g
+File 'd' exists only in p2, so 'h' should be from p2
+  $ hg cp d h
+File 'f' exists only in p1, so 'i' should be from p1
+  $ hg cp f i
+  $ hg ci -m 'merge'
+  $ hg changesetcopies
+  files: g h i
+  p1copies: g\x00a (esc)
+  i\x00f (esc)
+  p2copies: h\x00d (esc)
+
+Test writing to both changeset and filelog
+
+  $ hg cp a j
+  $ hg ci -m 'copy a to j' --config experimental.copies.write-to=compatibility
+  $ hg changesetcopies
+  files: j
+  p1copies: j\x00a (esc)
+  $ hg debugdata j 0
+  \x01 (esc)
+  copy: a
+  copyrev: b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3
+  \x01 (esc)
+  a
+
+Test writing only to filelog
+
+  $ hg cp a k
+  $ hg ci -m 'copy a to k' --config experimental.copies.write-to=filelog-only
+  $ hg changesetcopies
+  files: k
+  $ hg debugdata k 0
+  \x01 (esc)
+  copy: a
+  copyrev: b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3
+  \x01 (esc)
+  a
+
+  $ cd ..
diff --git a/tests/test-fastannotate-hg.t b/tests/test-fastannotate-hg.t
--- a/tests/test-fastannotate-hg.t
+++ b/tests/test-fastannotate-hg.t
@@ -443,7 +443,7 @@
   > def reposetup(ui, repo):
   >     class legacyrepo(repo.__class__):
   >         def _filecommit(self, fctx, manifest1, manifest2,
-  >                         linkrev, tr, changelist):
+  >                         linkrev, tr, changelist, includecopymeta):
   >             fname = fctx.path()
   >             text = fctx.data()
   >             flog = self.file(fname)