[PATCH 4.4 40/69] dm mirror: fix read error on recovery after default leg failure

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Heinz Mauelshagen <heinzm@xxxxxxxxxx>

commit dcb2ff56417362c31f6b430c3c531a84581e8721 upstream.

If a default leg has failed, any read will cause a new operational
default leg to be selected and the read is resubmitted.  But until now
the read will return failure even though it was successful due to
resubmission.  The reason for this is bio->bi_error was not being
cleared before resubmitting the bio.

Fix by clearing bio->bi_error before resubmission.

Fixes: 4246a0b63bd8 ("block: add a bi_error field to struct bio")
Signed-off-by: Heinz Mauelshagen <heinzm@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/md/dm-raid1.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1288,6 +1288,7 @@ static int mirror_end_io(struct dm_targe
 
 			dm_bio_restore(bd, bio);
 			bio_record->details.bi_bdev = NULL;
+			bio->bi_error = 0;
 
 			queue_bio(ms, bio, rw);
 			return DM_ENDIO_INCOMPLETE;