1693 persistent 'comment' field for a zpool

*** 18,27 ****
--- 18,29 ----
   *
   * CDDL HEADER END
   */
  /*
   * Copyright (c) 2007, 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.
   */
  
  #include <sys/zio.h>
  #include <sys/spa.h>
  #include <sys/zfs_acl.h>
*** 67,76 ****
--- 69,80 ----
              ZFS_TYPE_POOL, "<path>", "ALTROOT");
          zprop_register_string(ZPOOL_PROP_BOOTFS, "bootfs", NULL, PROP_DEFAULT,
              ZFS_TYPE_POOL, "<filesystem>", "BOOTFS");
          zprop_register_string(ZPOOL_PROP_CACHEFILE, "cachefile", NULL,
              PROP_DEFAULT, ZFS_TYPE_POOL, "<file> | none", "CACHEFILE");
+         zprop_register_string(ZPOOL_PROP_COMMENT, "comment", NULL,
+             PROP_DEFAULT, ZFS_TYPE_POOL, "<comment-string>", "COMMENT");
  
          /* readonly number properties */
          zprop_register_number(ZPOOL_PROP_SIZE, "size", 0, PROP_READONLY,
              ZFS_TYPE_POOL, "<size>", "SIZE");
          zprop_register_number(ZPOOL_PROP_FREE, "free", 0, PROP_READONLY,