md: assorted md and raid1 one-liners

Fix few bugs that meant that:
  - superblocks weren't alway written at exactly the right time (this
    could show up if the array was not written to - writting to the array
    causes lots of superblock updates and so hides these errors).

  - restarting device recovery after a clean shutdown (version-1 metadata
    only) didn't work as intended (or at all).

1/ Ensure superblock is updated when a new device is added.
2/ Remove an inappropriate test on MD_RECOVERY_SYNC in md_do_sync.
   The body of this if takes one of two branches depending on whether
   MD_RECOVERY_SYNC is set, so testing it in the clause of the if
   is wrong.
3/ Flag superblock for updating after a resync/recovery finishes.
4/ If we find the neeed to restart a recovery in the middle (version-1
   metadata only) make sure a full recovery (not just as guided by
   bitmaps) does get done.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

drivers/md/md.c

@@ -3160,6 +3160,7 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
 		if (err)
 			export_rdev(rdev);
 
+		md_update_sb(mddev);
 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 		md_wakeup_thread(mddev->thread);
 		return err;
@@ -4679,7 +4680,6 @@ static void md_do_sync(mddev_t *mddev)
 	mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
 
 	if (!test_bit(MD_RECOVERY_ERR, &mddev->recovery) &&
-	    mddev->curr_resync > 2 &&
 	    mddev->curr_resync >= mddev->recovery_cp) {
 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
 			printk(KERN_INFO 

drivers/md/raid1.c

@@ -1898,6 +1898,7 @@ static int run(mddev_t *mddev)
 		if (!disk->rdev) {
 			disk->head_position = 0;
 			mddev->degraded++;
+			conf->fullsync = 1;
 		}
 	}