diff --git a/docs/changelog.rst b/docs/changelog.rst
index cdc160be..99b30214 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -164,6 +164,10 @@ Fixes
   environment variable if it is set, causing behaviour to diverge when Ansible
   was invoked across user accounts via ``sudo``.
 
+* `#364 <https://github.com/dw/mitogen/issues/364>`_: file transfers from
+  controllers running Python 2.7.2 or earlier could be interrupted due to a
+  forking bug in the :mod:`tempfile` module.
+
 * `#370 <https://github.com/dw/mitogen/issues/370>`_: the Ansible
   `reboot <https://docs.ansible.com/ansible/latest/modules/reboot_module.html>`_
   module is supported.
diff --git a/mitogen/core.py b/mitogen/core.py
index b1519c90..cb64fc92 100644
--- a/mitogen/core.py
+++ b/mitogen/core.py
@@ -721,13 +721,19 @@ class Sender(object):
         _vv and IOLOG.debug('%r.send(%r..)', self, repr(data)[:100])
         self.context.send(Message.pickled(data, handle=self.dst_handle))
 
+    explicit_close_msg = 'Sender was explicitly closed'
+
     def close(self):
         """
         Send a dead message to the remote, causing :meth:`ChannelError` to be
         raised in any waiting thread.
         """
         _vv and IOLOG.debug('%r.close()', self)
-        self.context.send(Message.dead(handle=self.dst_handle))
+        self.context.send(
+            Message.dead(
+                reason=self.explicit_close_msg,
+                handle=self.dst_handle)
+        )
 
     def __repr__(self):
         return 'Sender(%r, %r)' % (self.context, self.dst_handle)
diff --git a/mitogen/service.py b/mitogen/service.py
index dc90b67f..0bafc899 100644
--- a/mitogen/service.py
+++ b/mitogen/service.py
@@ -754,8 +754,8 @@ class FileService(Service):
 
     def __init__(self, router):
         super(FileService, self).__init__(router)
-        #: Mapping of registered path -> file size.
-        self._metadata_by_path = {}
+        #: Set of registered paths.
+        self._paths = set()
         #: Mapping of Stream->FileStreamState.
         self._state_by_stream = {}
 
@@ -772,20 +772,21 @@ class FileService(Service):
     def register(self, path):
         """
         Authorize a path for access by children. Repeat calls with the same
-        path is harmless.
+        path has no effect.
 
         :param str path:
             File path.
         """
-        if path in self._metadata_by_path:
-            return
+        if path not in self._paths:
+            LOG.debug('%r: registering %r', self, path)
+            self._paths.add(path)
 
+    def _generate_stat(self, path):
         st = os.stat(path)
         if not stat.S_ISREG(st.st_mode):
             raise IOError('%r is not a regular file.' % (path,))
 
-        LOG.debug('%r: registering %r', self, path)
-        self._metadata_by_path[path] = {
+        return {
             'size': st.st_size,
             'mode': st.st_mode,
             'owner': self._name_or_none(pwd.getpwuid, 0, 'pw_name'),
@@ -869,26 +870,26 @@ class FileService(Service):
         :raises Error:
             Unregistered path, or Sender did not match requestee context.
         """
-        if path not in self._metadata_by_path:
+        if path not in self._paths:
             raise Error(self.unregistered_msg)
         if msg.src_id != sender.context.context_id:
             raise Error(self.context_mismatch_msg)
 
         LOG.debug('Serving %r', path)
+
+        # Response must arrive first so requestee can begin receive loop,
+        # otherwise first ack won't arrive until all pending chunks were
+        # delivered. In that case max BDP would always be 128KiB, aka. max
+        # ~10Mbit/sec over a 100ms link.
         try:
             fp = open(path, 'rb', self.IO_SIZE)
+            msg.reply(self._generate_stat(path))
         except IOError:
             msg.reply(mitogen.core.CallError(
                 sys.exc_info()[1]
             ))
             return
 
-        # Response must arrive first so requestee can begin receive loop,
-        # otherwise first ack won't arrive until all pending chunks were
-        # delivered. In that case max BDP would always be 128KiB, aka. max
-        # ~10Mbit/sec over a 100ms link.
-        msg.reply(self._metadata_by_path[path])
-
         stream = self.router.stream_by_id(sender.context.context_id)
         state = self._state_by_stream.setdefault(stream, FileStreamState())
         state.lock.acquire()
@@ -949,6 +950,7 @@ class FileService(Service):
             sender=recv.to_sender(),
         )
 
+        received_bytes = 0
         for chunk in recv:
             s = chunk.unpickle()
             LOG.debug('get_file(%r): received %d bytes', path, len(s))
@@ -958,11 +960,19 @@ class FileService(Service):
                 size=len(s),
             ).close()
             out_fp.write(s)
+            received_bytes += len(s)
 
-        ok = out_fp.tell() == metadata['size']
-        if not ok:
+        ok = received_bytes == metadata['size']
+        if received_bytes < metadata['size']:
             LOG.error('get_file(%r): receiver was closed early, controller '
-                      'is likely shutting down.', path)
+                      'may be shutting down, or the file was truncated '
+                      'during transfer. Expected %d bytes, received %d.',
+                      path, metadata['size'], received_bytes)
+        elif received_bytes > metadata['size']:
+            LOG.error('get_file(%r): the file appears to have grown '
+                      'while transfer was in progress. Expected %d '
+                      'bytes, received %d.',
+                      path, metadata['size'], received_bytes)
 
         LOG.debug('target.get_file(): fetched %d bytes of %r from %r in %dms',
                   metadata['size'], path, context, 1000 * (time.time() - t0))
diff --git a/tests/ansible/integration/action/copy.yml b/tests/ansible/integration/action/copy.yml
index d799be90..c3e961f6 100644
--- a/tests/ansible/integration/action/copy.yml
+++ b/tests/ansible/integration/action/copy.yml
@@ -1,6 +1,6 @@
 # Verify copy module for small and large files, and inline content.
 
-- name: integration/action/synchronize.yml
+- name: integration/action/copy.yml
   hosts: test-targets
   any_errors_fatal: true
   tasks: