[PATCH 4.9 51/53] Revert "Dont jump to compute_result state from check_result state"

[Greg Kroah-Hartman]

From: Song Liu <songliubraving@xxxxxx>

commit a25d8c327bb41742dbd59f8c545f59f3b9c39983 upstream.

This reverts commit 4f4fd7c5798bbdd5a03a60f6269cf1177fbd11ef.

Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Nigel Croxon <ncroxon@xxxxxxxxxx>
Cc: Xiao Ni <xni@xxxxxxxxxx>
Signed-off-by: Song Liu <songliubraving@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/md/raid5.c |   19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3914,15 +3914,26 @@ static void handle_parity_checks6(struct
 	case check_state_check_result:
 		sh->check_state = check_state_idle;
 
-		if (s->failed > 1)
-			break;
 		/* handle a successful check operation, if parity is correct
 		 * we are done.  Otherwise update the mismatch count and repair
 		 * parity if !MD_RECOVERY_CHECK
 		 */
 		if (sh->ops.zero_sum_result == 0) {
-			/* Any parity checked was correct */
-			set_bit(STRIPE_INSYNC, &sh->state);
+			/* both parities are correct */
+			if (!s->failed)
+				set_bit(STRIPE_INSYNC, &sh->state);
+			else {
+				/* in contrast to the raid5 case we can validate
+				 * parity, but still have a failure to write
+				 * back
+				 */
+				sh->check_state = check_state_compute_result;
+				/* Returning at this point means that we may go
+				 * off and bring p and/or q uptodate again so
+				 * we make sure to check zero_sum_result again
+				 * to verify if p or q need writeback
+				 */
+			}
 		} else {
 			atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
 			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))