xref: /titanic_41/usr/src/uts/common/fs/zfs/uberblock.c (revision 80e2ca8596e3435bc3b76f3c597833ea0a87f85e)
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 }
64