Commit 834f9f61 authored Oct 17, 2011 by Jeff Moyer Committed by Jens Axboe Oct 24, 2011

blk-flush: fix invalid BUG_ON in blk_insert_flush

A user reported a regression due to commit
4853abaa (block: fix flush
machinery for stacking drivers with differring flush flags).
Part of the problem is that blk_insert_flush required a
single bio be attached to the request.  In reality, having
no attached bio is also a valid case, as can be observed with
an empty flush.

[1] http://www.redhat.com/archives/dm-devel/2011-September/msg00154.html



Reported-by: Christophe Saout <christophe@saout.de>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>

Stable note: 3.1
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 456be148

block/blk-flush.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -320,7 +320,7 @@ void blk_insert_flush(struct request *rq)
		return;
		}

		BUG_ON(!rq->bio \|\| rq->bio != rq->biotail);
		BUG_ON(rq->bio != rq->biotail); /assumes zero or single bio rq /

		/*
		* If there's data but flush is not necessary, the request can be

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