curzone reality check and teardown changes to use the RIGHT zone

*** 409,418 ****
--- 409,419 ----
  rfs_climb_crossmnt(vnode_t **dvpp, struct exportinfo **exip, cred_t *cr)
  {
          struct exportinfo *exi;
          vnode_t *dvp = *dvpp;
  
+         ASSERT3P((*exip)->exi_zone, ==, curzone);
          ASSERT((dvp->v_flag & VROOT) || VN_IS_CURZONEROOT(dvp));
  
          VN_HOLD(dvp);
          dvp = untraverse(dvp);
          exi = nfs_vptoexi(NULL, dvp, cr, NULL, NULL, FALSE);
*** 419,428 ****
--- 420,430 ----
          if (exi == NULL) {
                  VN_RELE(dvp);
                  return (-1);
          }
  
+         ASSERT3P(exi->exi_zone, ==, curzone);
          exi_rele(*exip);
          *exip = exi;
          VN_RELE(*dvpp);
          *dvpp = dvp;
  
*** 479,488 ****
--- 481,491 ----
                          return;
                  }
          }
  
          exi_hold(exi);
+         ASSERT3P(exi->exi_zone, ==, curzone);
  
          /*
           * Not allow lookup beyond root.
           * If the filehandle matches a filehandle of the exi,
           * then the ".." refers beyond the root of an exported filesystem.
*** 1310,1319 ****
--- 1313,1323 ----
          cred_t *savecred;
          int in_crit = 0;
          caller_context_t ct;
          nfs_srv_t *nsrv;
  
+         ASSERT3P(curzone, ==, ((exi == NULL) ? curzone : exi->exi_zone));
          nsrv = zone_getspecific(rfs_zone_key, curzone);
          if (!nsrv->write_async) {
                  rfs_write_sync(wa, ns, exi, req, cr, ro);
                  return;
          }