xref: /illumos-gate/usr/src/uts/common/fs/zfs/uberblock.c (revision 438b5f69eb4f998015cc0835f19f2f80663f2f53)
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 }
62