1693 persistent 'comment' field for a zpool

@@ -18,10 +18,11 @@
  *
  * 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

@@ -110,10 +111,11 @@
 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 */