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  * Copyright (c) 2013, 2017 by Delphix. All rights reserved.
  24  */
  25
  26 #include <sys/zfs_context.h>
  27 #include <sys/uberblock_impl.h>
  28 #include <sys/vdev_impl.h>
  29
  30 int
  31 uberblock_verify(uberblock_t *ub)
  32 {
  33         if (ub->ub_magic == BSWAP_64((uint64_t)UBERBLOCK_MAGIC))
  34                 byteswap_uint64_array(ub, sizeof (uberblock_t));
  35
  36         if (ub->ub_magic != UBERBLOCK_MAGIC)
  37                 return (SET_ERROR(EINVAL));
  38
  39         return (0);
  40 }
  41
  42 /*
  43  * Update the uberblock and return TRUE if anything changed in this
  44  * transaction group.
  45  */
  46 boolean_t
  47 uberblock_update(uberblock_t *ub, vdev_t *rvd, uint64_t txg, uint64_t mmp_delay)
  48 {
  49         ASSERT(ub->ub_txg < txg);
  50
  51         /*
  52          * We explicitly do not set ub_version here, so that older versions
  53          * continue to be written with the previous uberblock version.
  54          */
  55         ub->ub_magic = UBERBLOCK_MAGIC;
  56         ub->ub_txg = txg;
  57         ub->ub_guid_sum = rvd->vdev_guid_sum;
  58         ub->ub_timestamp = gethrestime_sec();
  59         ub->ub_software_version = SPA_VERSION;
  60         ub->ub_mmp_magic = MMP_MAGIC;
  61         ub->ub_mmp_delay = spa_multihost(rvd->vdev_spa) ? mmp_delay : 0;
  62         ub->ub_mmp_seq = 0;
  63         ub->ub_checkpoint_txg = 0;
  64
  65         return (ub->ub_rootbp.blk_birth == txg);
  66 }