2882 implement libzfs_core
2883 changing "canmount" property to "on" should not always remount dataset
2900 "zfs snapshot" should be able to create multiple, arbitrary snapshots at once
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Chris Siden <christopher.siden@delphix.com>
Reviewed by: Garrett D'Amore <garrett@damore.org>
Reviewed by: Bill Pijewski <wdp@joyent.com>
Reviewed by: Dan Kruchinin <dan.kruchinin@gmail.com>

*** 46,56 ****
  dmu_tx_t *
  dmu_tx_create_dd(dsl_dir_t *dd)
  {
          dmu_tx_t *tx = kmem_zalloc(sizeof (dmu_tx_t), KM_SLEEP);
          tx->tx_dir = dd;
!         if (dd)
                  tx->tx_pool = dd->dd_pool;
          list_create(&tx->tx_holds, sizeof (dmu_tx_hold_t),
              offsetof(dmu_tx_hold_t, txh_node));
          list_create(&tx->tx_callbacks, sizeof (dmu_tx_callback_t),
              offsetof(dmu_tx_callback_t, dcb_node));
--- 46,56 ----
  dmu_tx_t *
  dmu_tx_create_dd(dsl_dir_t *dd)
  {
          dmu_tx_t *tx = kmem_zalloc(sizeof (dmu_tx_t), KM_SLEEP);
          tx->tx_dir = dd;
!         if (dd != NULL)
                  tx->tx_pool = dd->dd_pool;
          list_create(&tx->tx_holds, sizeof (dmu_tx_hold_t),
              offsetof(dmu_tx_hold_t, txh_node));
          list_create(&tx->tx_callbacks, sizeof (dmu_tx_callback_t),
              offsetof(dmu_tx_callback_t, dcb_node));