2619 asynchronous destruction of ZFS file systems
2747 SPA versioning with zfs feature flags
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <gwilson@delphix.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Reviewed by: Dan Kruchinin <dan.kruchinin@gmail.com>
Approved by: Dan McDonald <danmcd@nexenta.com>

*** 1326,1336 ****
           */
          if (vd->vdev_ops->vdev_op_leaf && vdev_readable(vd)) {
                  uint64_t aux_guid = 0;
                  nvlist_t *nvl;
  
!                 if ((label = vdev_label_read_config(vd)) == NULL) {
                          vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
                              VDEV_AUX_BAD_LABEL);
                          return (0);
                  }
  
--- 1326,1337 ----
           */
          if (vd->vdev_ops->vdev_op_leaf && vdev_readable(vd)) {
                  uint64_t aux_guid = 0;
                  nvlist_t *nvl;
  
!                 if ((label = vdev_label_read_config(vd, VDEV_BEST_LABEL)) ==
!                     NULL) {
                          vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
                              VDEV_AUX_BAD_LABEL);
                          return (0);
                  }
  
*** 1967,1984 ****
          uint64_t state;
  
          if (!vdev_readable(vd))
                  return (0);
  
!         if ((label = vdev_label_read_config(vd)) == NULL) {
                  vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
                      VDEV_AUX_CORRUPT_DATA);
                  return (-1);
          }
  
          if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_VERSION, &version) != 0 ||
!             version > SPA_VERSION ||
              nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID, &guid) != 0 ||
              guid != vd->vdev_guid ||
              nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_STATE, &state) != 0) {
                  vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
                      VDEV_AUX_CORRUPT_DATA);
--- 1968,1985 ----
          uint64_t state;
  
          if (!vdev_readable(vd))
                  return (0);
  
!         if ((label = vdev_label_read_config(vd, VDEV_BEST_LABEL)) == NULL) {
                  vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
                      VDEV_AUX_CORRUPT_DATA);
                  return (-1);
          }
  
          if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_VERSION, &version) != 0 ||
!             !SPA_VERSION_IS_SUPPORTED(version) ||
              nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID, &guid) != 0 ||
              guid != vd->vdev_guid ||
              nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_STATE, &state) != 0) {
                  vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
                      VDEV_AUX_CORRUPT_DATA);