From: NeilBrown <neilb@suse.de>

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 drivers/md/md.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff -puN drivers/md/md.c~md-add-error-reporting-to-superblock-write-failure drivers/md/md.c
--- a/drivers/md/md.c~md-add-error-reporting-to-superblock-write-failure
+++ a/drivers/md/md.c
@@ -389,8 +389,12 @@ static int super_written(struct bio *bio
 	if (bio->bi_size)
 		return 1;
 
-	if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags))
+	if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags)) {
+		printk("md: super_written gets error=%d, uptodate=%d\n",
+		       error, test_bit(BIO_UPTODATE, &bio->bi_flags));
+		WARN_ON(test_bit(BIO_UPTODATE, &bio->bi_flags));
 		md_error(mddev, rdev);
+	}
 
 	if (atomic_dec_and_test(&mddev->pending_writes))
 		wake_up(&mddev->sb_wait);
_