diff --git a/git_config.py b/git_config.py
index 76031a0..9d5162e 100644
--- a/git_config.py
+++ b/git_config.py
@@ -285,12 +285,14 @@
         return True
     return False
 
-  def ResetFetch(self):
+  def ResetFetch(self, mirror=False):
     """Set the fetch refspec to its default value.
     """
-    self.fetch = [RefSpec(True,
-                          'refs/heads/*',
-                          'refs/remotes/%s/*' % self.name)]
+    if mirror:
+      dst = 'refs/heads/*'
+    else:
+      dst = 'refs/remotes/%s/*' % self.name
+    self.fetch = [RefSpec(True, 'refs/heads/*', dst)]
 
   def Save(self):
     """Save this remote to the configuration.
diff --git a/manifest.py b/manifest.py
index b928cdf..ea68b68 100644
--- a/manifest.py
+++ b/manifest.py
@@ -88,6 +88,10 @@
     self._Load()
     return self._default
 
+  @property
+  def IsMirror(self):
+    return self.manifestProject.config.GetBoolean('repo.mirror')
+
   def _Unload(self):
     self._loaded = False
     self._projects = {}
@@ -114,6 +118,10 @@
         finally:
           self.manifestFile = real
 
+      if self.IsMirror:
+        self._AddMetaProjectMirror(self.repoProject)
+        self._AddMetaProjectMirror(self.manifestProject)
+
       self._loaded = True
 
   def _ParseManifest(self, is_root_file):
@@ -157,6 +165,40 @@
                 (project.name, self.manifestFile)
         self._projects[project.name] = project
 
+  def _AddMetaProjectMirror(self, m):
+    name = None
+    m_url = m.GetRemote(m.remote.name).url
+    if m_url.endswith('/.git'):
+      raise ManifestParseError, 'refusing to mirror %s' % m_url
+
+    if self._default and self._default.remote:
+      url = self._default.remote.fetchUrl
+      if not url.endswith('/'):
+        url += '/'
+      if m_url.startswith(url):
+        remote = self._default.remote
+        name = m_url[len(url):]
+
+    if name is None:
+      s = m_url.rindex('/') + 1
+      remote = Remote('origin', fetch = m_url[:s])
+      name = m_url[s:]
+
+    if name.endswith('.git'):
+      name = name[:-4]
+
+    if name not in self._projects:
+      m.PreSync()
+      gitdir = os.path.join(self.topdir, '%s.git' % name)
+      project = Project(manifest = self,
+                        name = name,
+                        remote = remote,
+                        gitdir = gitdir,
+                        worktree = None,
+                        relpath = None,
+                        revision = m.revision)
+      self._projects[project.name] = project
+
   def _ParseRemote(self, node):
     """
     reads a <remote> element from the manifest file
@@ -214,8 +256,13 @@
             "project %s path cannot be absolute in %s" % \
             (name, self.manifestFile)
 
-    worktree = os.path.join(self.topdir, path)
-    gitdir = os.path.join(self.repodir, 'projects/%s.git' % path)
+    if self.IsMirror:
+      relpath = None
+      worktree = None
+      gitdir = os.path.join(self.topdir, '%s.git' % name)
+    else:
+      worktree = os.path.join(self.topdir, path)
+      gitdir = os.path.join(self.repodir, 'projects/%s.git' % path)
 
     project = Project(manifest = self,
                       name = name,
@@ -242,8 +289,10 @@
   def _ParseCopyFile(self, project, node):
     src = self._reqatt(node, 'src')
     dest = self._reqatt(node, 'dest')
-    # src is project relative, and dest is relative to the top of the tree
-    project.AddCopyFile(src, os.path.join(self.topdir, dest))
+    if not self.IsMirror:
+      # src is project relative;
+      # dest is relative to the top of the tree
+      project.AddCopyFile(src, os.path.join(self.topdir, dest))
 
   def _get_remote(self, node):
     name = node.getAttribute('remote')
diff --git a/project.py b/project.py
index 0637f4b..1cfaaae 100644
--- a/project.py
+++ b/project.py
@@ -211,7 +211,10 @@
                     gitdir = self.gitdir,
                     defaults =  self.manifest.globalConfig)
 
-    self.work_git = self._GitGetByExec(self, bare=False)
+    if self.worktree:
+      self.work_git = self._GitGetByExec(self, bare=False)
+    else:
+      self.work_git = None
     self.bare_git = self._GitGetByExec(self, bare=True)
 
   @property
@@ -489,14 +492,23 @@
       print >>sys.stderr
       print >>sys.stderr, 'Initializing project %s ...' % self.name
       self._InitGitDir()
+
     self._InitRemote()
     for r in self.extraRemotes.values():
       if not self._RemoteFetch(r.name):
         return False
     if not self._RemoteFetch():
       return False
-    self._RepairAndroidImportErrors()
-    self._InitMRef()
+
+    if self.worktree:
+      self._RepairAndroidImportErrors()
+      self._InitMRef()
+    else:
+      self._InitMirrorHead()
+      try:
+        os.remove(os.path.join(self.gitdir, 'FETCH_HEAD'))
+      except OSError:
+        pass
     return True
 
   def PostRepoUpgrade(self):
@@ -792,9 +804,11 @@
   def _RemoteFetch(self, name=None):
     if not name:
       name = self.remote.name
-    return GitCommand(self,
-                      ['fetch', name],
-                      bare = True).Wait() == 0
+    cmd = ['fetch']
+    if not self.worktree:
+      cmd.append('--update-head-ok')
+    cmd.append(name)
+    return GitCommand(self, cmd, bare = True).Wait() == 0
 
   def _Checkout(self, rev, quiet=False):
     cmd = ['checkout']
@@ -874,7 +888,10 @@
       remote.url = url
       remote.review = self.remote.reviewUrl
 
-      remote.ResetFetch()
+      if self.worktree:
+        remote.ResetFetch(mirror=False)
+      else:
+        remote.ResetFetch(mirror=True)
       remote.Save()
 
     for r in self.extraRemotes.values():
@@ -897,6 +914,11 @@
         dst = remote.ToLocal(self.revision)
         self.bare_git.symbolic_ref('-m', msg, ref, dst)
 
+  def _InitMirrorHead(self):
+    dst = self.GetRemote(self.remote.name).ToLocal(self.revision)
+    msg = 'manifest set to %s' % self.revision
+    self.bare_git.SetHead(dst, message=msg)
+
   def _InitWorkTree(self):
     dotgit = os.path.join(self.worktree, '.git')
     if not os.path.exists(dotgit):
diff --git a/repo b/repo
index 9f107a9..bfa4ca3 100755
--- a/repo
+++ b/repo
@@ -28,7 +28,7 @@
 del magic
 
 # increment this whenever we make important changes to this script
-VERSION = (1, 6)
+VERSION = (1, 7)
 
 # increment this if the MAINTAINER_KEYS block is modified
 KEYRING_VERSION = (1,0)
@@ -115,6 +115,9 @@
 group.add_option('-m', '--manifest-name',
                  dest='manifest_name',
                  help='initial manifest file', metavar='NAME.xml')
+group.add_option('--mirror',
+                 dest='mirror', action='store_true',
+                 help='mirror the forrest')
 
 # Tool
 group = init_optparse.add_option_group('Version options')
diff --git a/subcmds/init.py b/subcmds/init.py
index 03f358d..ad28a61 100644
--- a/subcmds/init.py
+++ b/subcmds/init.py
@@ -57,6 +57,10 @@
     g.add_option('-m', '--manifest-name',
                  dest='manifest_name', default='default.xml',
                  help='initial manifest file', metavar='NAME.xml')
+    g.add_option('--mirror',
+                 dest='mirror', action='store_true',
+                 help='mirror the forrest')
+
 
     # Tool
     g = p.add_option_group('Version options')
@@ -112,6 +116,9 @@
       r.ResetFetch()
       r.Save()
 
+    if opt.mirror:
+      m.config.SetString('repo.mirror', 'true')
+
     m.Sync_NetworkHalf()
     m.Sync_LocalHalf()
     m.StartBranch('default')
@@ -185,9 +192,14 @@
     self._SyncManifest(opt)
     self._LinkManifest(opt.manifest_name)
 
-    if os.isatty(0) and os.isatty(1):
+    if os.isatty(0) and os.isatty(1) and not opt.mirror:
       self._ConfigureUser()
       self._ConfigureColor()
 
+    if opt.mirror:
+      type = 'mirror '
+    else:
+      type = ''
+
     print ''
-    print 'repo initialized in %s' % self.manifest.topdir
+    print 'repo %sinitialized in %s' % (type, self.manifest.topdir)
diff --git a/subcmds/sync.py b/subcmds/sync.py
index 9af1232..8050e51 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -102,8 +102,9 @@
       self._Fetch(*missing)
 
     for project in all:
-      if not project.Sync_LocalHalf():
-        sys.exit(1)
+      if project.worktree:
+        if not project.Sync_LocalHalf():
+          sys.exit(1)
 
 
 def _VerifyTag(project):