[PATCH] dm_crypt: Issue all previous bios before remapping barrier bio

[Nikanth Karthikesan <knikanth@suse.de>]

Before remapping a barrier bio, make sure that there are no un-issued
pending I/O in the workqueue. Otherwise a dm_flush would simply add
a barrier request to the underlying device, without issuing the bio's
queued in the dm_crypt device.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>

--

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index a936372..be68e70 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1252,6 +1252,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
 
 	if (unlikely(bio_empty_barrier(bio))) {
 		cc = ti->private;
+		flush_workqueue(cc->io_queue);
 		bio->bi_bdev = cc->dev->bdev;
 		return DM_MAPIO_REMAPPED;
 	}