Revert exi_zone to exi_zoneid, and install exi_ne backpointer

@@ -415,11 +415,11 @@
 rfs_climb_crossmnt(vnode_t **dvpp, struct exportinfo **exip, cred_t *cr)
 {
         struct exportinfo *exi;
         vnode_t *dvp = *dvpp;
 
-        ASSERT3P((*exip)->exi_zone, ==, curzone);
+        ASSERT3U((*exip)->exi_zoneid, ==, curzone->zone_id);
         ASSERT((dvp->v_flag & VROOT) || VN_IS_CURZONEROOT(dvp));
 
         VN_HOLD(dvp);
         dvp = untraverse(dvp);
         exi = nfs_vptoexi(NULL, dvp, cr, NULL, NULL, FALSE);

@@ -426,11 +426,11 @@
         if (exi == NULL) {
                 VN_RELE(dvp);
                 return (-1);
         }
 
-        ASSERT3P(exi->exi_zone, ==, curzone);
+        ASSERT3U(exi->exi_zoneid, ==, curzone->zone_id);
         exi_rele(*exip);
         *exip = exi;
         VN_RELE(*dvpp);
         *dvpp = dvp;
 

@@ -487,11 +487,11 @@
                         return;
                 }
         }
 
         exi_hold(exi);
-        ASSERT3P(exi->exi_zone, ==, curzone);
+        ASSERT3U(exi->exi_zoneid, ==, curzone->zone_id);
 
         /*
          * Not allow lookup beyond root.
          * If the filehandle matches a filehandle of the exi,
          * then the ".." refers beyond the root of an exported filesystem.