storage: fix volume shrink on unaligned volumes

host/storage/storage.go

@@ -356,34 +356,30 @@ func (vm *VolumeManager) shrinkVolume(ctx context.Context, id int, oldMaxSectors
 		return fmt.Errorf("failed to migrate sectors: %w", err)
 	}
 
-	var batchSize uint64 = resizeBatchSize
-	for current := oldMaxSectors; current > newMaxSectors; current -= batchSize {
+	for current := oldMaxSectors; current > newMaxSectors; {
 		// stop early if the context is cancelled
 		select {
 		case <-ctx.Done():
 			return ctx.Err()
 		default:
 		}
 
-		var target uint64
-		if current < batchSize {
-			target = newMaxSectors
-			batchSize = current - newMaxSectors
-		} else {
-			target = current - batchSize
+		target := newMaxSectors
+		if current-target > resizeBatchSize {
+			target = current - resizeBatchSize
 		}
-		// shrink in chunks to prevent holding a lock for too long and to
-		// track progress.
+
 		if err := vm.vs.ShrinkVolume(id, target); err != nil {
 			return fmt.Errorf("failed to expand volume metadata: %w", err)
 		} else if err := volume.Resize(target); err != nil {
 			return fmt.Errorf("failed to shrink volume data to %v sectors: %w", target, err)
 		}
-		// update the alert
-		a.Data["currentSectors"] = target
-		vm.a.Register(a)
-		// sleep to allow other operations to run
-		time.Sleep(time.Millisecond)
+
+		if current > resizeBatchSize {
+			current -= resizeBatchSize
+		} else {
+			current = newMaxSectors
+		}
 	}
 	return nil
 }