diff --git a/paramiko/file.py b/paramiko/file.py
index 501ba9f..442e433 100644
--- a/paramiko/file.py
+++ b/paramiko/file.py
@@ -314,7 +314,7 @@ class BufferedFile (object):
                 last_newline_pos += len(wbuf) - len(data)
                 self._write_all(wbuf[:last_newline_pos + 1])
                 self._wbuffer = StringIO()
-                self._wbuffer.write(wbuf[last_newline_pos+1:])
+                self._wbuffer.write(wbuf[last_newline_pos + 1:])
             return
         # even if we're line buffering, if the buffer has grown past the
         # buffer size, force a flush.
@@ -412,16 +412,15 @@ class BufferedFile (object):
     def _write_all(self, data):
         # the underlying stream may be something that does partial writes (like
         # a socket).
-        total = len(data)
-        while data:
+        while len(data) > 0:
             count = self._write(data)
             data = data[count:]
-        if self._flags & _FLAG_APPEND:
-            self._size += total
-            self._pos = self._realpos = self._size
-        else:
-            self._pos += total
-            self._realpos += total
+            if self._flags & _FLAG_APPEND:
+                self._size += count
+                self._pos = self._realpos = self._size
+            else:
+                self._pos += count
+                self._realpos += count
         return None
 
     def _record_newline(self, newline):
diff --git a/paramiko/sftp_file.py b/paramiko/sftp_file.py
index 612153b..a2c8902 100644
--- a/paramiko/sftp_file.py
+++ b/paramiko/sftp_file.py
@@ -1,6 +1,6 @@
 #!/usr/bin/python
 
-# Copyright (C) 2003-2004 Robey Pointer <robey@lag.net>
+# Copyright (C) 2003-2005 Robey Pointer <robey@lag.net>
 #
 # This file is part of paramiko.
 #
@@ -55,13 +55,14 @@ class SFTPFile (BufferedFile):
         return msg.get_string()
 
     def _write(self, data):
-        offset = 0
-        while offset < len(data):
-            chunk = min(len(data) - offset, self.MAX_REQUEST_SIZE)
-            t, msg = self.sftp._request(CMD_WRITE, self.handle, long(self._realpos + offset),
-                                        str(data[offset : offset + chunk]))
-            offset += chunk
-        return len(data)
+        # may write less than requested if it would exceed max packet size
+        chunk = min(len(data), self.MAX_REQUEST_SIZE)
+        t, msg = self.sftp._request(CMD_WRITE, self.handle, long(self._realpos),
+                                    str(data[:chunk]))
+        if t != CMD_STATUS:
+            raise SFTPError('Expected status')
+        self.sftp._convert_status(msg)
+        return chunk
 
     def settimeout(self, timeout):
         """
diff --git a/tests/test_sftp.py b/tests/test_sftp.py
index 72ca195..ba00a18 100755
--- a/tests/test_sftp.py
+++ b/tests/test_sftp.py
@@ -438,7 +438,24 @@ class SFTPTest (unittest.TestCase):
         finally:
             sftp.remove('%s/hongry.txt' % FOLDER)
 
-    def test_E_realpath(self):
+    def test_E_big_file_no_buffer(self):
+        """
+        write a 1MB file, with no linefeeds, and no buffering.
+        """
+        global g_big_file_test
+        if not g_big_file_test:
+            return
+        kblob = (1024 * 1024 * 'x')
+        try:
+            f = sftp.open('%s/hongry.txt' % FOLDER, 'w')
+            f.write(kblob)
+            f.close()
+
+            self.assertEqual(sftp.stat('%s/hongry.txt' % FOLDER).st_size, 1024 * 1024)
+        finally:
+            sftp.remove('%s/hongry.txt' % FOLDER)
+            
+    def test_F_realpath(self):
         """
         test that realpath is returning something non-empty and not an
         error.
@@ -449,7 +466,7 @@ class SFTPTest (unittest.TestCase):
         self.assert_(len(f) > 0)
         self.assertEquals(os.path.join(pwd, FOLDER), f)
 
-    def test_F_mkdir(self):
+    def test_G_mkdir(self):
         """
         verify that mkdir/rmdir work.
         """