diff options
| -rw-r--r-- | block/blk-barrier.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/block/blk-barrier.c b/block/blk-barrier.c index c63044e9c4c0..8eba4e43bb0c 100644 --- a/block/blk-barrier.c +++ b/block/blk-barrier.c @@ -166,9 +166,21 @@ static inline bool start_ordered(struct request_queue *q, struct request **rqp) * For an empty barrier, there's no actual BAR request, which * in turn makes POSTFLUSH unnecessary. Mask them off. */ - if (!rq->hard_nr_sectors) + if (!rq->hard_nr_sectors) { q->ordered &= ~(QUEUE_ORDERED_DO_BAR | QUEUE_ORDERED_DO_POSTFLUSH); + /* + * Empty barrier on a write-through device w/ ordered + * tag has no command to issue and without any command + * to issue, ordering by tag can't be used. Drain + * instead. + */ + if ((q->ordered & QUEUE_ORDERED_BY_TAG) && + !(q->ordered & QUEUE_ORDERED_DO_PREFLUSH)) { + q->ordered &= ~QUEUE_ORDERED_BY_TAG; + q->ordered |= QUEUE_ORDERED_BY_DRAIN; + } + } /* stash away the original request */ elv_dequeue_request(q, rq); |