jbd2_journal_extend
return jbd2_journal_extend(handle, nblocks, revoke);
EXPORT_SYMBOL(jbd2_journal_extend);
status = jbd2_journal_extend(handle, nblocks, 0);
status = jbd2_journal_extend(handle, OCFS2_MAX_TRANS_DATA, 0);
extern int jbd2_journal_extend(handle_t *handle, int nblocks,