Commit 6cff88ba authored by Alexander Larsson's avatar Alexander Larsson Committed by Alexander Larsson
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Bug 575555 – Use fsync() when replacing files to avoid data loss on

2009-03-16  Alexander Larsson  <alexl@redhat.com>

	Bug 575555 – Use fsync() when replacing files to avoid data loss on crash

        * configure.in:
	Look for fsync().

        * glib/gfileutils.c:
        (write_to_temp_file):
	fsync temp file if destination file exists

2009-03-16  Alexander Larsson  <alexl@redhat.com>

	Bug 575555 – Use fsync() when replacing files to avoid data loss on crash

        * glocalfileoutputstream.c:
        (g_local_file_output_stream_close):
        (_g_local_file_output_stream_replace):
	fsync temp file before closing if replacing target file

	

svn path=/trunk/; revision=7991
parent 0b66e52e
2009-03-16 Alexander Larsson <alexl@redhat.com>
Bug 575555 – Use fsync() when replacing files to avoid data loss on crash
* configure.in:
Look for fsync().
* glib/gfileutils.c:
(write_to_temp_file):
fsync temp file if destination file exists
2009-03-13 Matthias Clasen <mclasen@redhat.com>
* configure.in: Bump version
......
......@@ -563,6 +563,7 @@ AC_CHECK_FUNCS(mmap)
AC_CHECK_FUNCS(posix_memalign)
AC_CHECK_FUNCS(memalign)
AC_CHECK_FUNCS(valloc)
AC_CHECK_FUNCS(fsync)
AC_CHECK_FUNCS(atexit on_exit)
......
2009-03-16 Alexander Larsson <alexl@redhat.com>
Bug 575555 – Use fsync() when replacing files to avoid data loss on crash
* glocalfileoutputstream.c:
(g_local_file_output_stream_close):
(_g_local_file_output_stream_replace):
fsync temp file before closing if replacing target file
2009-03-13 Matthias Clasen <mclasen@redhat.com>
* === Released 2.20.0 ===
......
......@@ -69,6 +69,7 @@ struct _GLocalFileOutputStreamPrivate {
char *original_filename;
char *backup_filename;
char *etag;
gboolean sync_on_close;
int fd;
};
......@@ -190,6 +191,20 @@ g_local_file_output_stream_close (GOutputStream *stream,
file = G_LOCAL_FILE_OUTPUT_STREAM (stream);
#ifdef HAVE_FSYNC
if (file->priv->sync_on_close &&
fsync (file->priv->fd) != 0)
{
int errsv = errno;
g_set_error (error, G_IO_ERROR,
g_io_error_from_errno (errno),
_("Error writing to file: %s"),
g_strerror (errsv));
goto err_out;
}
#endif
#ifdef G_OS_WIN32
/* Must close before renaming on Windows, so just do the close first
......@@ -976,6 +991,7 @@ _g_local_file_output_stream_replace (const char *filename,
int mode;
int fd;
char *temp_file;
gboolean sync_on_close;
if (g_cancellable_set_error_if_cancelled (cancellable, error))
return NULL;
......@@ -986,6 +1002,7 @@ _g_local_file_output_stream_replace (const char *filename,
mode = 0600;
else
mode = 0666;
sync_on_close = FALSE;
/* If the file doesn't exist, create it */
fd = g_open (filename, O_CREAT | O_EXCL | O_WRONLY | O_BINARY, mode);
......@@ -997,6 +1014,14 @@ _g_local_file_output_stream_replace (const char *filename,
flags, cancellable, error);
if (fd == -1)
return NULL;
/* If the final destination exists, we want to sync the newly written
* file to ensure the data is on disk when we rename over the destination.
* otherwise if we get a system crash we can lose both the new and the
* old file on some filesystems. (I.E. those that don't guarantee the
* data is written to the disk before the metadata.)
*/
sync_on_close = TRUE;
}
else if (fd == -1)
{
......@@ -1022,6 +1047,7 @@ _g_local_file_output_stream_replace (const char *filename,
stream = g_object_new (G_TYPE_LOCAL_FILE_OUTPUT_STREAM, NULL);
stream->priv->fd = fd;
stream->priv->sync_on_close = sync_on_close;
stream->priv->tmp_filename = temp_file;
if (create_backup)
stream->priv->backup_filename = create_backup_filename (filename);
......
......@@ -868,7 +868,7 @@ rename_file (const char *old_name,
static gchar *
write_to_temp_file (const gchar *contents,
gssize length,
const gchar *template,
const gchar *dest_file,
GError **err)
{
gchar *tmp_name;
......@@ -880,7 +880,7 @@ write_to_temp_file (const gchar *contents,
retval = NULL;
tmp_name = g_strdup_printf ("%s.XXXXXX", template);
tmp_name = g_strdup_printf ("%s.XXXXXX", dest_file);
errno = 0;
fd = create_temp_file (tmp_name, 0666);
......@@ -942,11 +942,54 @@ write_to_temp_file (const gchar *contents,
goto out;
}
}
errno = 0;
if (fflush (file) != 0)
{
save_errno = errno;
g_set_error (err,
G_FILE_ERROR,
g_file_error_from_errno (save_errno),
_("Failed to write file '%s': fflush() failed: %s"),
display_name,
g_strerror (save_errno));
g_unlink (tmp_name);
goto out;
}
#ifdef HAVE_FSYNC
errno = 0;
/* If the final destination exists, we want to sync the newly written
* file to ensure the data is on disk when we rename over the destination.
* otherwise if we get a system crash we can lose both the new and the
* old file on some filesystems. (I.E. those that don't guarantee the
* data is written to the disk before the metadata.)
*/
if (g_file_test (dest_file, G_FILE_TEST_EXISTS) &&
fsync (fileno (file)) != 0)
{
save_errno = errno;
g_set_error (err,
G_FILE_ERROR,
g_file_error_from_errno (save_errno),
_("Failed to write file '%s': fsync() failed: %s"),
display_name,
g_strerror (save_errno));
g_unlink (tmp_name);
goto out;
}
#endif
errno = 0;
if (fclose (file) == EOF)
{
save_errno = 0;
save_errno = errno;
g_set_error (err,
G_FILE_ERROR,
......
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