9286 want refreservation=auto

*** 19,29 ****
   * CDDL HEADER END
   */
  
  /*
   * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
!  * Copyright (c) 2013, Joyent, Inc. All rights reserved.
   * Copyright (c) 2011, 2016 by Delphix. All rights reserved.
   * Copyright (c) 2012 DEY Storage Systems, Inc.  All rights reserved.
   * Copyright (c) 2011-2012 Pawel Jakub Dawidek. All rights reserved.
   * Copyright (c) 2013 Martin Matuska. All rights reserved.
   * Copyright (c) 2013 Steven Hartland. All rights reserved.
--- 19,29 ----
   * CDDL HEADER END
   */
  
  /*
   * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
!  * Copyright (c) 2018, Joyent, Inc. All rights reserved.
   * Copyright (c) 2011, 2016 by Delphix. All rights reserved.
   * Copyright (c) 2012 DEY Storage Systems, Inc.  All rights reserved.
   * Copyright (c) 2011-2012 Pawel Jakub Dawidek. All rights reserved.
   * Copyright (c) 2013 Martin Matuska. All rights reserved.
   * Copyright (c) 2013 Steven Hartland. All rights reserved.
*** 1386,1396 ****
                          char buf[64];
  
                          switch (prop) {
                          case ZFS_PROP_RESERVATION:
                          case ZFS_PROP_REFRESERVATION:
!                                 if (intval > volsize) {
                                          zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                              "'%s' is greater than current "
                                              "volume size"), propname);
                                          (void) zfs_error(hdl, EZFS_BADPROP,
                                              errbuf);
--- 1386,1396 ----
                          char buf[64];
  
                          switch (prop) {
                          case ZFS_PROP_RESERVATION:
                          case ZFS_PROP_REFRESERVATION:
!                                 if (intval > volsize && intval != UINT64_MAX) {
                                          zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                                              "'%s' is greater than current "
                                              "volume size"), propname);
                                          (void) zfs_error(hdl, EZFS_BADPROP,
                                              errbuf);
*** 1497,1506 ****
--- 1497,1555 ----
                  return (-1);
          }
          return (1);
  }
  
+ /*
+  * Helper for 'zfs {set|clone} [ref]reservation=auto'.  Must be called after
+  * zfs_valid_proplist(), as it is what sets the UINT64_MAX sentinal value.
+  * Return codes must match zfs_add_synthetic_resv().
+  */
+ static int
+ zfs_fix_auto_resv(zfs_handle_t *zhp, nvlist_t *nvl)
+ {
+         uint64_t volsize;
+         uint64_t resvsize;
+         zfs_prop_t prop;
+         nvlist_t *props;
+ 
+         if (!ZFS_IS_VOLUME(zhp)) {
+                 return (0);
+         }
+ 
+         if (zfs_which_resv_prop(zhp, &prop) != 0) {
+                 return (-1);
+         }
+         if (nvlist_lookup_uint64(nvl, zfs_prop_to_name(prop), &resvsize) != 0) {
+                 /* No value being set, so it can't be "auto" */
+                 return (0);
+         }
+         if (resvsize != UINT64_MAX) {
+                 /* Being set to a value other than "auto" */
+                 return (0);
+         }
+ 
+         props = fnvlist_alloc();
+ 
+         fnvlist_add_uint64(props, zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE),
+             zfs_prop_get_int(zhp, ZFS_PROP_VOLBLOCKSIZE));
+ 
+         if (nvlist_lookup_uint64(nvl, zfs_prop_to_name(ZFS_PROP_VOLSIZE),
+             &volsize) != 0) {
+                 volsize = zfs_prop_get_int(zhp, ZFS_PROP_VOLSIZE);
+         }
+ 
+         resvsize = zvol_volsize_to_reservation(volsize, props);
+         fnvlist_free(props);
+ 
+         if (nvlist_add_uint64(nvl, zfs_prop_to_name(prop), resvsize) != 0) {
+                 (void) no_memory(zhp->zfs_hdl);
+                 return (-1);
+         }
+         return (1);
+ }
+ 
  void
  zfs_setprop_error(libzfs_handle_t *hdl, zfs_prop_t prop, int err,
      char *errbuf)
  {
          switch (err) {
*** 1662,1671 ****
--- 1711,1726 ----
                  if (zfs_name_to_prop(nvpair_name(elem)) == ZFS_PROP_VOLSIZE &&
                      (added_resv = zfs_add_synthetic_resv(zhp, nvl)) == -1) {
                          goto error;
                  }
          }
+ 
+         if (added_resv != 1 &&
+             (added_resv = zfs_fix_auto_resv(zhp, nvl)) == -1) {
+                 goto error;
+         }
+ 
          /*
           * Check how many properties we're setting and allocate an array to
           * store changelist pointers for postfix().
           */
          nvl_len = 0;
*** 3664,3682 ****
--- 3719,3742 ----
  
          /* do the clone */
  
          if (props) {
                  zfs_type_t type;
+ 
                  if (ZFS_IS_VOLUME(zhp)) {
                          type = ZFS_TYPE_VOLUME;
                  } else {
                          type = ZFS_TYPE_FILESYSTEM;
                  }
                  if ((props = zfs_valid_proplist(hdl, type, props, zoned,
                      zhp, zhp->zpool_hdl, errbuf)) == NULL)
                          return (-1);
+                 if (zfs_fix_auto_resv(zhp, props) == -1) {
+                         nvlist_free(props);
+                         return (-1);
                  }
+         }
  
          ret = lzc_clone(target, zhp->zfs_name, props);
          nvlist_free(props);
  
          if (ret != 0) {