1693 persistent 'comment' field for a zpool

*** 18,27 ****
--- 18,28 ----
   *
   * CDDL HEADER END
   */
  /*
   * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+  * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
   * Copyright (c) 2011 by Delphix. All rights reserved.
   * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
   */
  
  #ifndef _SYS_SPA_IMPL_H
*** 110,119 ****
--- 111,121 ----
  struct spa {
          /*
           * Fields protected by spa_namespace_lock.
           */
          char            spa_name[MAXNAMELEN];   /* pool name */
+         char            *spa_comment;           /* comment */
          avl_node_t      spa_avl;                /* node in spa_namespace_avl */
          nvlist_t        *spa_config;            /* last synced config */
          nvlist_t        *spa_config_syncing;    /* currently syncing config */
          nvlist_t        *spa_config_splitting;  /* config for splitting */
          nvlist_t        *spa_load_info;         /* info and errors from load */