module/zfs/uberblock.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  23  */
  24
  25 #include <sys/zfs_context.h>
  26 #include <sys/uberblock_impl.h>
  27 #include <sys/vdev_impl.h>
  28
  29 int
  30 uberblock_verify(uberblock_t *ub)
  31 {
  32         if (ub->ub_magic == BSWAP_64((uint64_t)UBERBLOCK_MAGIC))
  33                 byteswap_uint64_array(ub, sizeof (uberblock_t));
  34
  35         if (ub->ub_magic != UBERBLOCK_MAGIC)
  36                 return (EINVAL);
  37
  38         return (0);
  39 }
  40
  41 /*
  42  * Update the uberblock and return a boolean value indicating whether
  43  * anything changed in this transaction group.
  44  */
  45 int
  46 uberblock_update(uberblock_t *ub, vdev_t *rvd, uint64_t txg)
  47 {
  48         ASSERT(ub->ub_txg < txg);
  49
  50         /*
  51          * We explicitly do not set ub_version here, so that older versions
  52          * continue to be written with the previous uberblock version.
  53          */
  54         ub->ub_magic = UBERBLOCK_MAGIC;
  55         ub->ub_txg = txg;
  56         ub->ub_guid_sum = rvd->vdev_guid_sum;
  57         ub->ub_timestamp = gethrestime_sec();
  58         ub->ub_software_version = SPA_VERSION;
  59
  60         return (ub->ub_rootbp.blk_birth == txg);
  61 }