teuthology: Add support for seek and sync in write_file

teuthology/orchestra/remote.py

@@ -265,22 +265,34 @@ def read_file(self, path, sudo=False, stdout=None,
 
 
     def write_file(self, path, data, sudo=False, mode=None, owner=None,
-                                     mkdir=False, append=False):
+                                     mkdir=False, append=False, bs=None,
+                                     offset=None, sync=False):
         """
         Write data to remote file
 
+        The data written in 512-byte blocks, provide `bs` to use bigger blocks.
+
         :param path:    file path on remote host
         :param data:    str, binary or fileobj to be written
         :param sudo:    use sudo to write file, defaults False
         :param mode:    set file mode bits if provided
         :param owner:   set file owner if provided
         :param mkdir:   preliminary create the file directory, defaults False
         :param append:  append data to the file, defaults False
+        :param bs:      write up to N bytes at a time if provided, default is 512 in `dd`
+        :param offset:  number of bs blocks to seek to in file, defaults 0
+        :param sync:    sync file after write is complete if provided
         """
         dd = 'sudo dd' if sudo else 'dd'
         args = dd + ' of=' + path
         if append:
             args += ' conv=notrunc oflag=append'
+        if bs:
+            args += ' bs=' + str(bs)
+        if offset:
+            args += ' seek=' + str(offset)
+        if sync:
+            args += ' conv=sync'
         if mkdir:
             mkdirp = 'sudo mkdir -p' if sudo else 'mkdir -p'
             dirpath = os.path.dirname(path)

teuthology/orchestra/test/test_remote.py

@@ -220,3 +220,15 @@ def test_is_container(self):
         rem2 = remote.Remote(name='[email protected]', ssh=self.m_ssh)
         rem2._runner = m_run
         assert not rem2.is_container
+
+    @patch("teuthology.orchestra.remote.Remote.run")
+    def test_write_file(self, m_run):
+        file = "fakefile"
+        contents = "fakecontents"
+        rem = remote.Remote(name='[email protected]', ssh=self.m_ssh)
+
+        remote.Remote.write_file(rem, file, contents, bs=1, offset=1024)
+        m_run.assert_called_with(args=f"set -ex\ndd of={file} bs=1 seek=1024", stdin=contents, quiet=True)
+
+        remote.Remote.write_file(rem, file, contents, sync=True)
+        m_run.assert_called_with(args=f"set -ex\ndd of={file} conv=sync", stdin=contents, quiet=True)