libceph: add support for primary_temp mappings

Change apply_temp() to override primary in the same way pg_temp
overrides osd set.  primary_temp overrides pg_temp primary too.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>

net/ceph/osdmap.c

@@ -1597,7 +1597,7 @@ static int raw_to_up_osds(struct ceph_osdmap *osdmap,
 }
 
 /*
- * Given up set, apply pg_temp mapping.
+ * Given up set, apply pg_temp and primary_temp mappings.
  *
  * Return acting set length.  *primary is set to acting primary osd id,
  * or -1 if acting set is empty.
@@ -1644,6 +1644,11 @@ static int apply_temps(struct ceph_osdmap *osdmap,
 		temp_primary = *primary;
 	}
 
+	/* primary_temp? */
+	pg = __lookup_pg_mapping(&osdmap->primary_temp, pgid);
+	if (pg)
+		temp_primary = pg->primary_temp.osd;
+
 	*primary = temp_primary;
 	return temp_len;
 }