blk-flush: fix invalid BUG_ON in blk_insert_flush
authorJeff Moyer <jmoyer@redhat.com>
Mon, 17 Oct 2011 10:57:22 +0000 (12:57 +0200)
committerGreg Kroah-Hartman <gregkh@suse.de>
Fri, 11 Nov 2011 17:44:34 +0000 (09:44 -0800)
commitd16a63a89dcb0cece02469b3bb17062c3d48656f
tree689f93069725114ceea9e917d5ec44ea68d7fe1a
parente0aef70cc677fdfaa195b04eea389a9b9b40eeaa
blk-flush: fix invalid BUG_ON in blk_insert_flush

commit 834f9f61a525d2f6d3d0c93894e26326c8d3ceed upstream.

A user reported a regression due to commit
4853abaae7e4a2af938115ce9071ef8684fb7af4 (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>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
block/blk-flush.c