---

yaml
---
r: 197511
b: refs/heads/master
c: a8707c0
h: refs/heads/master
i:
  197509: 6b8c5d7
  197507: d7a1951
  197503: b1632ee
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7b0bb5368a7195606eca475d9f4e291ab7227052
+refs/heads/master: a8707c08f4f718bb0ed65499d3f43201f6e41455

trunk/drivers/md/md.c

@@ -2088,7 +2088,6 @@ static void sync_sbs(mddev_t * mddev, int nospares)
 		if (rdev->sb_events == mddev->events ||
 		    (nospares &&
 		     rdev->raid_disk < 0 &&
-		     (rdev->sb_events&1)==0 &&
 		     rdev->sb_events+1 == mddev->events)) {
 			/* Don't update this superblock */
 			rdev->sb_loaded = 2;
@@ -2141,28 +2140,14 @@ static void md_update_sb(mddev_t * mddev, int force_change)
 	 * and 'events' is odd, we can roll back to the previous clean state */
 	if (nospares
 	    && (mddev->in_sync && mddev->recovery_cp == MaxSector)
-	    && (mddev->events & 1)
-	    && mddev->events != 1)
+	    && mddev->can_decrease_events
+	    && mddev->events != 1) {
 		mddev->events--;
-	else {
+		mddev->can_decrease_events = 0;
+	} else {
 		/* otherwise we have to go forward and ... */
 		mddev->events ++;
-		if (!mddev->in_sync || mddev->recovery_cp != MaxSector) { /* not clean */
-			/* .. if the array isn't clean, an 'even' event must also go
-			 * to spares. */
-			if ((mddev->events&1)==0) {
-				nospares = 0;
-				sync_req = 2; /* force a second update to get the
-					       * even/odd in sync */
-			}
-		} else {
-			/* otherwise an 'odd' event must go to spares */
-			if ((mddev->events&1)) {
-				nospares = 0;
-				sync_req = 2; /* force a second update to get the
-					       * even/odd in sync */
-			}
-		}
+		mddev->can_decrease_events = nospares;
 	}
 
 	if (!mddev->events) {
@@ -4606,6 +4591,7 @@ static void md_clean(mddev_t *mddev)
 	mddev->layout = 0;
 	mddev->max_disks = 0;
 	mddev->events = 0;
+	mddev->can_decrease_events = 0;
 	mddev->delta_disks = 0;
 	mddev->new_level = LEVEL_NONE;
 	mddev->new_layout = 0;

trunk/drivers/md/md.h

@@ -150,6 +150,12 @@ struct mddev_s
 	int				external_size; /* size managed
 							* externally */
 	__u64				events;
+	/* If the last 'event' was simply a clean->dirty transition, and
+	 * we didn't write it to the spares, then it is safe and simple
+	 * to just decrement the event count on a dirty->clean transition.
+	 * So we record that possibility here.
+	 */
+	int				can_decrease_events;
 
 	char				uuid[16];