jbd2_journal_get_write_access
err = jbd2_journal_get_write_access(handle, bh);
if (jbd2_journal_get_write_access(handle, sbh)) {
EXPORT_SYMBOL(jbd2_journal_get_write_access);
status = jbd2_journal_get_write_access(handle, bh);
extern int jbd2_journal_get_write_access(handle_t *, struct buffer_head *);