Steffen Daode Nurpmeso <sdao...@googlemail.com> added the comment:
> Are you willing to update your patch accordingly?
I'm a vain rooster! I've used fullfsync() in 11877-standalone.1.diff!
Sorry for that, haypo. :-/
11877.fullsync-1.diff uses fullsync() and will instead always be
provided when fsync() is available, to which it will fall back if
no special operating system functionality is available.
I really think this is the cleanest solution, because like this
a user can state "i want the strongest guarantees available on
data integrity", and Python does just that.
--Steffen
Ciao, sdaoden(*)(gmail.com)
ASCII ribbon campaign ( ) More nuclear fission plants
against HTML e-mail X can serve more coloured
and proprietary attachments / \ and sounding animations
----------
Added file: http://bugs.python.org/file22759/11877.fullsync-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
@@ -706,6 +706,31 @@
Availability: Unix, and Windows starting in 2.2.3.
+.. function:: fullsync(fd)
+
+ The POSIX standart requires that :c:func:`fsync` must transfer the buffered
+ data to the storage device, not that the data is actually written by the
+ device itself. It explicitely leaves it up to operating system implementors
+ whether users are given stronger guarantees on data integrity or not. Some
+ systems also offer special functions which overtake the part of making such
+ stronger guarantees, i.e., Mac OS X and NetBSD. :func:`fullsync` is
+ identical to :func:`fsync` unless there is such special functionality
+ available, in which case that will be used.
+ To strive for best-possible data integrity, the following can be done::
+
+ # Force writeout of local buffer modifications
+ f.flush()
+ # Then synchronize the changes to physical backing store
+ if hasattr(os, 'fsync'):
+ os.fullsync(f.fileno())
+
+ ..note::
+ Calling this function may take a long time, since it may block
+ until the disk reports that the transfer has been completed.
+
+ Availability: See :func:`fsync`.
+
+
.. function:: ftruncate(fd, length)
Truncate the file corresponding to file descriptor *fd*, so that it is at
most
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -554,7 +554,7 @@
class TestInvalidFD(unittest.TestCase):
singles = ["fchdir", "fdopen", "dup", "fdatasync", "fstat",
- "fstatvfs", "fsync", "tcgetpgrp", "ttyname"]
+ "fstatvfs", "fsync", "fullsync", "tcgetpgrp", "ttyname"]
#singles.append("close")
#We omit close because it doesn'r raise an exception on some platforms
def get_single(f):
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -1855,6 +1855,42 @@
{
return posix_fildes(fdobj, fsync);
}
+
+PyDoc_STRVAR(fullsync__doc__,
+"fullsync(fd)\n\n"
+"force write of file buffers to disk, and the flush of disk caches\n"
+"of the file given by file descriptor fd.");
+
+static PyObject *
+fullsync(PyObject *self, PyObject *fdobj)
+{
+ /* See issue 11877 discussion */
+ int res, fd = PyObject_AsFileDescriptor(fdobj);
+ if (fd < 0)
+ return NULL;
+ if (!_PyVerify_fd(fd))
+ return posix_error();
+
+ Py_BEGIN_ALLOW_THREADS
+# if defined __APPLE__
+ /* F_FULLFSYNC is not supported for all types of FDs/FSYSs;
+ * be on the safe side and test for inappropriate ioctl errors.
+ * Because plain fsync() may succeed even then, let it decide about error
*/
+ res = fcntl(fd, F_FULLFSYNC);
+ if (res < 0 && errno == ENOTTY)
+ res = fsync(fd);
+# elif defined __NetBSD__
+ res = fsync_range(fd, FFILESYNC | FDISKSYNC, 0, 0);
+# else
+ res = fsync(fd);
+# endif
+ Py_END_ALLOW_THREADS
+
+ if (res < 0)
+ return posix_error();
+ Py_INCREF(Py_None);
+ return Py_None;
+}
#endif /* HAVE_FSYNC */
#ifdef HAVE_FDATASYNC
@@ -8953,6 +8989,7 @@
#endif
#ifdef HAVE_FSYNC
{"fsync", posix_fsync, METH_O, posix_fsync__doc__},
+ {"fullsync", fullsync, METH_O, fullsync__doc__},
#endif
#ifdef HAVE_FDATASYNC
{"fdatasync", posix_fdatasync, METH_O, posix_fdatasync__doc__},
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