xref: /illumos-gate/usr/src/uts/common/fs/zfs/uberblock.c (revision 88f8b78a88cbdc6d8c1af5c3e54bc49d25095c98)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <sys/zfs_context.h>
30 #include <sys/uberblock_impl.h>
31 #include <sys/vdev_impl.h>
32 
33 /* Keep the uberblock version in a varialbe so we can get at it with mdb */
34 static uint64_t uberblock_version = UBERBLOCK_VERSION;
35 
36 int
37 uberblock_verify(uberblock_t *ub)
38 {
39 	if (ub->ub_magic == BSWAP_64((uint64_t)UBERBLOCK_MAGIC))
40 		byteswap_uint64_array(ub, sizeof (uberblock_t));
41 
42 	if (ub->ub_magic != UBERBLOCK_MAGIC)
43 		return (EINVAL);
44 
45 	if (ub->ub_version != UBERBLOCK_VERSION)
46 		return (ENOTSUP);
47 
48 	return (0);
49 }
50 
51 /*
52  * Update the uberblock and return a boolean value indicating whether
53  * anything changed in this transaction group.
54  */
55 int
56 uberblock_update(uberblock_t *ub, vdev_t *rvd, uint64_t txg)
57 {
58 	ASSERT(ub->ub_txg < txg);
59 
60 	ub->ub_magic = UBERBLOCK_MAGIC;
61 	ub->ub_version = UBERBLOCK_VERSION;
62 	ub->ub_txg = txg;
63 	ub->ub_guid_sum = rvd->vdev_guid_sum;
64 	ub->ub_timestamp = gethrestime_sec();
65 
66 	return (ub->ub_rootbp.blk_birth == txg);
67 }
68