uberblock.c revision 219089 
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
29int
30uberblock_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 */
45int
46uberblock_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}
62