Commit ae5b2ec8 authored Nov 08, 2016 by Jens Axboe

block: set REQ_SYNC if we clear REQ_FUA|REQ_PREFLUSH



If we insert a flush request, we clear REQ_PREFLUSH and/or REQ_FUA,
depending on flush settings. Since op_is_sync() factors those flags
in for deciding whether this request is sync or not, we should
set REQ_SYNC to avoid screwing up this accounting.

This should be less fragile.

Reported-by: Logan Gunthorpe <logang@deltatee.com>
Fixes: b685d3d6 ("block: treat REQ_FUA and REQ_PREFLUSH as synchronous")
Signed-off-by: Jens Axboe <axboe@fb.com>

parent b57d74af

block/blk-flush.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -395,6 +395,13 @@ void blk_insert_flush(struct request *rq)
		if (!(fflags & (1UL << QUEUE_FLAG_FUA)))
		rq->cmd_flags &= ~REQ_FUA;

		/*
		* REQ_PREFLUSH\|REQ_FUA implies REQ_SYNC, so if we clear any
		* of those flags, we have to set REQ_SYNC to avoid skewing
		* the request accounting.
		*/
		rq->cmd_flags \|= REQ_SYNC;

		/*
		* An empty flush handed down from a stacking driver may
		* translate into nothing if the underlying device does not