From 07a83c47cfc00ba5f0f090ccddd3a0703be0eec9 Mon Sep 17 00:00:00 2001 From: Stefan Bader Date: Thu, 12 Jul 2007 17:28:33 +0100 Subject: dm: disable barriers This patch causes device-mapper to reject any barrier requests. This is done since most of the targets won't handle this correctly anyway. So until the situation improves it is better to reject these requests at the first place. Since barrier requests won't get to the targets, the checks there can be removed. Cc: stable@kernel.org Signed-off-by: Stefan Bader Signed-off-by: Alasdair G Kergon Signed-off-by: Linus Torvalds --- drivers/md/dm.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'drivers/md/dm.c') diff --git a/drivers/md/dm.c b/drivers/md/dm.c index b5e56af8f85..f4f7d35561a 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -800,6 +800,15 @@ static int dm_request(request_queue_t *q, struct bio *bio) int rw = bio_data_dir(bio); struct mapped_device *md = q->queuedata; + /* + * There is no use in forwarding any barrier request since we can't + * guarantee it is (or can be) handled by the targets correctly. + */ + if (unlikely(bio_barrier(bio))) { + bio_endio(bio, bio->bi_size, -EOPNOTSUPP); + return 0; + } + down_read(&md->io_lock); disk_stat_inc(dm_disk(md), ios[rw]); -- cgit v1.2.3