diff --git a/ansible_mitogen/connection.py b/ansible_mitogen/connection.py
index c5c96f24..12626485 100644
--- a/ansible_mitogen/connection.py
+++ b/ansible_mitogen/connection.py
@@ -880,13 +880,11 @@ class Connection(ansible.plugins.connection.ConnectionBase):
             path=mitogen.utils.cast(in_path)
         )
 
-        # A roundtrip is always necessary for the target to request the file
-        # from FileService, however, by pipelining the transfer function, the
-        # subsequent step (probably a module invocation) can get its
-        # dependencies and function call in-flight before the transfer is
-        # complete. This saves at least 1 RTT between the transfer completing
-        # and the start of the follow-up task.
-        self.get_chain().call_no_reply(
+        # For now this must remain synchronous, as the action plug-in may have
+        # passed us a temporary file to transfer. A future FileService could
+        # maintain an LRU list of open file descriptors to keep the temporary
+        # file alive, but that requires more work.
+        self.get_chain().call(
             ansible_mitogen.target.transfer_file,
             context=self.parent,
             in_path=in_path,
diff --git a/docs/changelog.rst b/docs/changelog.rst
index f4c46976..162a7c48 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -53,11 +53,6 @@ Enhancements
   a 250 ms link from 30 seconds to 10 seconds compared to v0.2.2, down from 120
   seconds compared to vanilla.
 
-* `49736b3a <https://github.com/dw/mitogen/commit/49736b3a>`_: avoid a
-  roundtrip when transferring files larger than 124KiB, removing a delay
-  between waiting for the transfer to complete and start of the follow-up
-  action.
-
 * `#337 <https://github.com/dw/mitogen/issues/337>`_: To avoid a scaling
   limitation, a PTY is no longer allocated for an SSH connection unless the
   configuration specifies a password.
diff --git a/tests/ansible/integration/action/all.yml b/tests/ansible/integration/action/all.yml
index c5cb80d7..75f77243 100644
--- a/tests/ansible/integration/action/all.yml
+++ b/tests/ansible/integration/action/all.yml
@@ -1,3 +1,4 @@
+- import_playbook: copy.yml
 - import_playbook: fixup_perms2__copy.yml
 - import_playbook: low_level_execute_command.yml
 - import_playbook: make_tmp_path.yml
diff --git a/tests/ansible/integration/action/copy.yml b/tests/ansible/integration/action/copy.yml
new file mode 100644
index 00000000..e3fca87f
--- /dev/null
+++ b/tests/ansible/integration/action/copy.yml
@@ -0,0 +1,66 @@
+# Verify copy module for small and large files, and inline content.
+
+- name: integration/action/synchronize.yml
+  hosts: test-targets
+  any_errors_fatal: true
+  tasks:
+    - copy:
+        dest: /tmp/copy-tiny-file
+        content:
+          this is a tiny file.
+      connection: local
+
+    - copy:
+        dest: /tmp/copy-large-file
+        # Must be larger than Connection.SMALL_SIZE_LIMIT.
+        content: "{% for x in range(200000) %}x{% endfor %}"
+      connection: local
+
+    # end of making files
+
+    - file:
+        state: absent
+        path: "{{item}}"
+      with_items:
+      - /tmp/copy-tiny-file.out
+      - /tmp/copy-large-file.out
+      - /tmp/copy-tiny-inline-file.out
+      - /tmp/copy-large-inline-file.out
+
+    # end of cleaning out files
+
+    - copy:
+        dest: /tmp/copy-large-file.out
+        src: /tmp/copy-large-file
+
+    - copy:
+        dest: /tmp/copy-tiny-file.out
+        src: /tmp/copy-tiny-file
+
+    - copy:
+        dest: /tmp/copy-tiny-inline-file.out
+        content: "tiny inline content"
+
+    - copy:
+        dest: /tmp/copy-large-inline-file.out
+        content: |
+          {% for x in range(200000) %}y{% endfor %}
+
+    # stat results
+
+    - stat:
+        path: "{{item}}"
+      with_items:
+      - /tmp/copy-tiny-file.out
+      - /tmp/copy-large-file.out
+      - /tmp/copy-tiny-inline-file.out
+      - /tmp/copy-large-inline-file.out
+      register: stat
+
+    - assert:
+        that:
+        - stat.results[0].stat.checksum == "f29faa9a6f19a700a941bf2aa5b281643c4ec8a0"
+        - stat.results[1].stat.checksum == "62951f943c41cdd326e5ce2b53a779e7916a820d"
+        - stat.results[2].stat.checksum == "b26dd6444595e2bdb342aa0a91721b57478b5029"
+        - stat.results[3].stat.checksum == "d675f47e467eae19e49032a2cc39118e12a6ee72"
+
diff --git a/tests/ansible/soak/_file_service_loop.yml b/tests/ansible/soak/_file_service_loop.yml
new file mode 100644
index 00000000..96111b3c
--- /dev/null
+++ b/tests/ansible/soak/_file_service_loop.yml
@@ -0,0 +1,6 @@
+  - file:
+      path: /tmp/foo-{{inventory_hostname}}
+      state: absent
+  - copy:
+      dest: /tmp/foo-{{inventory_hostname}}
+      content: "{{content}}"
diff --git a/tests/ansible/soak/file_service.yml b/tests/ansible/soak/file_service.yml
new file mode 100644
index 00000000..3b338b3c
--- /dev/null
+++ b/tests/ansible/soak/file_service.yml
@@ -0,0 +1,6 @@
+- hosts: all
+  tasks:
+  - set_fact:
+      content: "{% for x in range(126977) %}x{% endfor %}"
+  - include_tasks: _file_service_loop.yml
+    with_sequence: start=1 end=100