Re: NFS workload leaves nfsd threads in D state

[Christoph Hellwig <hch@lst.de>]

Only found a virtualized AHCI setup so far without much success.  Can
you try this (from Chengming Zhou) in the meantime?

diff --git a/block/blk-flush.c b/block/blk-flush.c
index dba392cf22bec6..5c392a277b9eb2 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -443,7 +443,7 @@ bool blk_insert_flush(struct request *rq)
 		 * the post flush, and then just pass the command on.
 		 */
 		blk_rq_init_flush(rq);
-		rq->flush.seq |= REQ_FSEQ_POSTFLUSH;
+		rq->flush.seq |= REQ_FSEQ_PREFLUSH;
 		spin_lock_irq(&fq->mq_flush_lock);
 		list_move_tail(&rq->flush.list, &fq->flush_data_in_flight);
 		spin_unlock_irq(&fq->mq_flush_lock);