On Fri, Oct 20, 2017 at 10:37:38AM +0300, Elena Reshetova wrote:

quoted

 	} else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
 		r = upgrade_mode(dd, mode, t->md);
 		if (r)
 			return r;
+		refcount_inc(&dd->count);
 	}

Missing here:

        else
		refcount_inc(&dd->count);

?

Oh, yes, thanks for catching this! I think this got unnoticed so far and patch was merged, so I am going to send a followup patch now. 

Best Regards,
Elena.

Alasdair