Index: Doc/library/os.rst
===================================================================
--- Doc/library/os.rst	(revision 65574)
+++ Doc/library/os.rst	(working copy)
@@ -577,7 +577,19 @@
    Truncate the file corresponding to file descriptor *fd*, so that it is at most
    *length* bytes in size. Availability: Macintosh, Unix.
 
+.. function:: fullfsync(fd)
 
+   Force disks to write file with filedescriptor *fd* to the actual physical media.
+   
+   Although :func:`fsync` flushes the operating system's file buffer to the storage device,
+   unsaved data may be waiting in the hardware write buffers on the storage device itself.
+   Certain operating systems (so far, only OS X) provide ``fullfsync`` to request that
+   the storage device flush its write buffer.
+   
+   If you're starting with a Python file object *f*, first do ``f.flush()``, then
+   ``os.fsync(f.fileno())``, and finally ``os.fullfsync(f.fileno())``, to ensure that
+   file *f* is completely saved to the storage media.  Availability: OS X starting in 2.6.
+
 .. function:: isatty(fd)
 
    Return ``True`` if the file descriptor *fd* is open and connected to a
Index: Modules/posixmodule.c
===================================================================
--- Modules/posixmodule.c	(revision 65574)
+++ Modules/posixmodule.c	(working copy)
@@ -1853,6 +1853,29 @@
 }
 #endif /* HAVE_FSYNC */
 
+#ifdef F_FULLFSYNC
+PyDoc_STRVAR(posix_fullfsync__doc__,
+"fullfsync(fildes)\n\n\
+force storage device to write file with filedescriptor to the final physical media.");
+
+static PyObject *
+posix_fullfsync(PyObject *self, PyObject *fdobj)
+{
+    int res;
+    int fd;
+    fd = PyObject_AsFileDescriptor(fdobj);
+    if (fd < 0)
+        return NULL;
+    Py_BEGIN_ALLOW_THREADS
+    res = fcntl(fd, F_FULLFSYNC, 0);
+    Py_END_ALLOW_THREADS
+    if (res < 0)
+        return posix_error();
+    Py_INCREF(Py_None);
+    return Py_None;
+}
+#endif /* F_FULLFSYNC */
+
 #ifdef HAVE_FDATASYNC
 
 #ifdef __hpux
@@ -8538,6 +8561,9 @@
 #ifdef HAVE_FSYNC
 	{"fsync",       posix_fsync, METH_O, posix_fsync__doc__},
 #endif
+#ifdef F_FULLFSYNC
+    {"fullfsync", posix_fullfsync, METH_O, posix_fullfsync__doc__},
+#endif
 #ifdef HAVE_FDATASYNC
 	{"fdatasync",   posix_fdatasync,  METH_O, posix_fdatasync__doc__},
 #endif