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 2006 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #pragma ident   "%Z%%M% %I%     %E% SMI"
  27
  28 #include <sys/zfs_context.h>
  29 #include <sys/uberblock_impl.h>
  30 #include <sys/vdev_impl.h>
  31
  32 int
  33 uberblock_verify(uberblock_t *ub)
  34 {
  35         if (ub->ub_magic == BSWAP_64((uint64_t)UBERBLOCK_MAGIC))
  36                 byteswap_uint64_array(ub, sizeof (uberblock_t));
  37
  38         if (ub->ub_magic != UBERBLOCK_MAGIC)
  39                 return (EINVAL);
  40
  41         return (0);
  42 }
  43
  44 /*
  45  * Update the uberblock and return a boolean value indicating whether
  46  * anything changed in this transaction group.
  47  */
  48 int
  49 uberblock_update(uberblock_t *ub, vdev_t *rvd, uint64_t txg)
  50 {
  51         ASSERT(ub->ub_txg < txg);
  52
  53         /*
  54          * We explicitly do not set ub_version here, so that older versions
  55          * continue to be written with the previous uberblock version.
  56          */
  57         ub->ub_magic = UBERBLOCK_MAGIC;
  58         ub->ub_txg = txg;
  59         ub->ub_guid_sum = rvd->vdev_guid_sum;
  60         ub->ub_timestamp = gethrestime_sec();
  61
  62         return (ub->ub_rootbp.blk_birth == txg);
  63 }