Steffen Daode Nurpmeso <sdao...@googlemail.com> added the comment:
Ronald Oussoren wrote:
> Adding the F_FULLSYNC option to os.fsync would be fine though
To show you that i'm not unteachable i'll attach a patch which
does that.
This approach can be heavily extended, then, e.g. by using
sync_file_range(all_the_flags) on Linux if the "full_fsync"
argument is true?! (And then there is sync_file_range2() on
PowerPC and nice ARM...)
(The first time that i use PyArg_xy plus plus - please review.
test_os is ok and using "os.fsync(xy, True)" makes test_zlib
succeed on unpatched hg checkout.
os.rst change is really ugly.)
----------
Added file: http://bugs.python.org/file21742/11877.optarg-1.diff
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue11877>
_______________________________________
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -798,7 +798,7 @@
Availability: Unix.
-.. function:: fsync(fd)
+.. function:: fsync(fd, full_fsync=False)
Force write of file with filedescriptor *fd* to disk. On Unix, this calls
the
native :c:func:`fsync` function; on Windows, the MS :c:func:`_commit`
function.
@@ -807,6 +807,13 @@
``f.flush()``, and then do ``os.fsync(f.fileno())``, to ensure that all
internal
buffers associated with *f* are written to disk.
+ Note that :c:func:`fsync` only ensures that the OS flushs all data to
+ the disk device, *not* that the data is actually written by the
+ device itself. For this to happen, use the *full_fsync* argument.
+ If this is true Python tries to accomplish even the device write,
+ e.g. on Mac OS X by calling :c:func:`fcntl` with the
+ :data:`F_FULLFSYNC` command.
+
Availability: Unix, and Windows.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -2119,12 +2119,38 @@
#ifdef HAVE_FSYNC
PyDoc_STRVAR(posix_fsync__doc__,
-"fsync(fildes)\n\n\
-force write of file with filedescriptor to disk.");
-
-static PyObject *
-posix_fsync(PyObject *self, PyObject *fdobj)
-{
+"fsync(fildes, full_fsync=False)\n\n"
+"force write of file with filedescriptor to disk.\n"
+"if full_fsync is True it also ensures write to physical backing store.");
+
+static PyObject *
+posix_fsync(PyObject *self, PyObject *args, PyObject *kwargs)
+{
+ auto PyObject *fdobj;
+ auto int full_fsync = 1;
+ static char *keywords[] = {"fd", "full_fsync", NULL };
+
+ if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O|i", keywords,
+ &fdobj, &full_fsync))
+ return NULL;
+
+# ifdef __APPLE__
+ /* See issue 11877 discussion and issue 11277 for OS X sparse file bug */
+ if (full_fsync != 0) {
+ int res, fd = PyObject_AsFileDescriptor(fdobj);
+ if (fd < 0)
+ return NULL;
+ if (!_PyVerify_fd(fd))
+ return posix_error();
+ Py_BEGIN_ALLOW_THREADS
+ res = fcntl(fd, F_FULLFSYNC);
+ Py_END_ALLOW_THREADS
+ if (res < 0)
+ return posix_error();
+ Py_INCREF(Py_None);
+ return Py_None;
+ }
+# endif
return posix_fildes(fdobj, fsync);
}
#endif /* HAVE_FSYNC */
@@ -9484,7 +9510,8 @@
{"fchdir", posix_fchdir, METH_O, posix_fchdir__doc__},
#endif
#ifdef HAVE_FSYNC
- {"fsync", posix_fsync, METH_O, posix_fsync__doc__},
+ {"fsync", (PyCFunction)posix_fsync, METH_VARARGS|METH_KEYWORDS,
+ posix_fsync__doc__},
#endif
#ifdef HAVE_SYNC
{"sync", posix_sync, METH_NOARGS, posix_sync__doc__},
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