md: don't set In_sync if array is frozen

When a disk is added to array, the following path is called in mdadm.

Manage_subdevs -> sysfs_freeze_array
               -> Manage_add
               -> sysfs_set_str(&info, NULL, "sync_action","idle")

Then from kernel side, Manage_add invokes the path (add_new_disk ->
validate_super = super_1_validate) to set In_sync flag.

Since In_sync means "device is in_sync with rest of array", and the new
added disk need to resync thread to help the synchronization of data.
And md_reap_sync_thread would call spare_active to set In_sync for the
new added disk finally. So don't set In_sync if array is in frozen.
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

drivers/md/md.c

@@ -1826,8 +1826,15 @@ static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
 				if (!(le32_to_cpu(sb->feature_map) &
 				      MD_FEATURE_RECOVERY_BITMAP))
 					rdev->saved_raid_disk = -1;
-			} else
-				set_bit(In_sync, &rdev->flags);
+			} else {
+				/*
+				 * If the array is FROZEN, then the device can't
+				 * be in_sync with rest of array.
+				 */
+				if (!test_bit(MD_RECOVERY_FROZEN,
+					      &mddev->recovery))
+					set_bit(In_sync, &rdev->flags);
+			}
 			rdev->raid_disk = role;
 			break;
 		}