md: make error_handler functions more uniform and correct.

- there is no need to test_bit Faulty, as that was already done in
  md_error which is the only caller of these functions.
- MD_CHANGE_DEVS should be set *after* faulty is set to ensure
  metadata is updated correctly.
- spinlock should be held while updating ->degraded.
Signed-off-by: NNeilBrown <neilb@suse.de>

  

drivers/md/multipath.c

@@ -186,6 +186,7 @@ static int multipath_congested(void *data, int bits)
 static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev)
 {
 	multipath_conf_t *conf = mddev->private;
+	char b[BDEVNAME_SIZE];
 
 	if (conf->raid_disks - mddev->degraded <= 1) {
 		/*
@@ -196,24 +197,25 @@ static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev)
 		printk(KERN_ALERT 
 		       "multipath: only one IO path left and IO error.\n");
 		/* leave it active... it's all we have */
-	} else {
+		return;
+	}
 	/*
 	 * Mark disk as unusable
 	 */
-		if (!test_bit(Faulty, &rdev->flags)) {
-			char b[BDEVNAME_SIZE];
-			clear_bit(In_sync, &rdev->flags);
+	if (test_and_clear_bit(In_sync, &rdev->flags)) {
+		unsigned long flags;
+		spin_lock_irqsave(&conf->device_lock, flags);
+		mddev->degraded++;
+		spin_unlock_irqrestore(&conf->device_lock, flags);
+	}
 	set_bit(Faulty, &rdev->flags);
 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
-			mddev->degraded++;
 	printk(KERN_ALERT "multipath: IO failure on %s,"
 	       " disabling IO path.\n"
 	       "multipath: Operation continuing"
 	       " on %d IO paths.\n",
-				bdevname (rdev->bdev,b),
+	       bdevname(rdev->bdev, b),
 	       conf->raid_disks - mddev->degraded);
-		}
-	}
 }
 
 static void print_multipath_conf (multipath_conf_t *conf)
@@ -273,9 +275,11 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 							   PAGE_CACHE_SIZE - 1);
 			}
 
+			spin_lock_irq(&conf->device_lock);
 			mddev->degraded--;
 			rdev->raid_disk = path;
 			set_bit(In_sync, &rdev->flags);
+			spin_unlock_irq(&conf->device_lock);
 			rcu_assign_pointer(p->rdev, rdev);
 			err = 0;
 			md_integrity_add_rdev(rdev, mddev);

drivers/md/raid5.c

@@ -1700,8 +1700,6 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev)
 	raid5_conf_t *conf = mddev->private;
 	pr_debug("raid456: error called\n");
 
-	if (!test_bit(Faulty, &rdev->flags)) {
-		set_bit(MD_CHANGE_DEVS, &mddev->flags);
 	if (test_and_clear_bit(In_sync, &rdev->flags)) {
 		unsigned long flags;
 		spin_lock_irqsave(&conf->device_lock, flags);
@@ -1713,6 +1711,7 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev)
 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
 	}
 	set_bit(Faulty, &rdev->flags);
+	set_bit(MD_CHANGE_DEVS, &mddev->flags);
 	printk(KERN_ALERT
 	       "md/raid:%s: Disk failure on %s, disabling device.\n"
 	       "md/raid:%s: Operation continuing on %d devices.\n",
@@ -1720,7 +1719,6 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev)
 	       bdevname(rdev->bdev, b),
 	       mdname(mddev),
 	       conf->raid_disks - mddev->degraded);
-	}
 }
 
 /*