Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md

Pull MD fixes from Shaohua Li:
 "Two small patches to fix long-lived raid5 stripe batch bugs, one from
  Dennis and the other from me"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md:
  md/raid5: preserve STRIPE_ON_UNPLUG_LIST in break_stripe_batch_list
  md/raid5: fix a race condition in stripe batch

Author: torvalds

drivers/md/raid5.c

@@ -811,15 +811,21 @@ static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh
 			spin_unlock(&head->batch_head->batch_lock);
 			goto unlock_out;
 		}
+		/*
+		 * We must assign batch_head of this stripe within the
+		 * batch_lock, otherwise clear_batch_ready of batch head
+		 * stripe could clear BATCH_READY bit of this stripe and
+		 * this stripe->batch_head doesn't get assigned, which
+		 * could confuse clear_batch_ready for this stripe
+		 */
+		sh->batch_head = head->batch_head;
 
 		/*
 		 * at this point, head's BATCH_READY could be cleared, but we
 		 * can still add the stripe to batch list
 		 */
 		list_add(&sh->batch_list, &head->batch_list);
 		spin_unlock(&head->batch_head->batch_lock);
-
-		sh->batch_head = head->batch_head;
 	} else {
 		head->batch_head = head;
 		sh->batch_head = head->batch_head;
@@ -4599,7 +4605,8 @@ static void break_stripe_batch_list(struct stripe_head *head_sh,
 
 		set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
 					    (1 << STRIPE_PREREAD_ACTIVE) |
-					    (1 << STRIPE_DEGRADED)),
+					    (1 << STRIPE_DEGRADED) |
+					    (1 << STRIPE_ON_UNPLUG_LIST)),
 			      head_sh->state & (1 << STRIPE_INSYNC));
 
 		sh->check_state = head_sh->check_state;