dlm_convert_lock
#define DLM_CONVERT_LOCK_MAX_LEN (sizeof(struct dlm_convert_lock)+DLM_LVB_LEN)
struct dlm_convert_lock convert;
memset(&convert, 0, sizeof(struct dlm_convert_lock));
vec[0].iov_len = sizeof(struct dlm_convert_lock);
struct dlm_convert_lock *cnv = (struct dlm_convert_lock *)msg->buf;