REQ_FSEQ_PREFLUSH
case REQ_FSEQ_PREFLUSH:
BUG_ON(seq != REQ_FSEQ_PREFLUSH && seq != REQ_FSEQ_POSTFLUSH);
policy |= REQ_FSEQ_PREFLUSH;
rq->flush.seq |= REQ_FSEQ_PREFLUSH;
REQ_FSEQ_ACTIONS = REQ_FSEQ_PREFLUSH | REQ_FSEQ_DATA |