| From 834f9f61a525d2f6d3d0c93894e26326c8d3ceed Mon Sep 17 00:00:00 2001 |
| From: Jeff Moyer <jmoyer@redhat.com> |
| Date: Mon, 17 Oct 2011 12:57:22 +0200 |
| Subject: blk-flush: fix invalid BUG_ON in blk_insert_flush |
| |
| From: Jeff Moyer <jmoyer@redhat.com> |
| |
| 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 | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/block/blk-flush.c |
| +++ b/block/blk-flush.c |
| @@ -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 |
