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) 2016, 2017 by Delphix. All rights reserved.
24 */
25
26#ifndef _SYS_UBERBLOCK_IMPL_H
27#define	_SYS_UBERBLOCK_IMPL_H
28
29#include <sys/uberblock.h>
30
31#ifdef	__cplusplus
32extern "C" {
33#endif
34
35/*
36 * The uberblock version is incremented whenever an incompatible on-disk
37 * format change is made to the SPA, DMU, or ZAP.
38 *
39 * Note: the first two fields should never be moved.  When a storage pool
40 * is opened, the uberblock must be read off the disk before the version
41 * can be checked.  If the ub_version field is moved, we may not detect
42 * version mismatch.  If the ub_magic field is moved, applications that
43 * expect the magic number in the first word won't work.
44 */
45#define	UBERBLOCK_MAGIC		0x00bab10c		/* oo-ba-bloc!	*/
46#define	UBERBLOCK_SHIFT		10			/* up to 1K	*/
47
48struct uberblock {
49	uint64_t	ub_magic;	/* UBERBLOCK_MAGIC		*/
50	uint64_t	ub_version;	/* SPA_VERSION			*/
51	uint64_t	ub_txg;		/* txg of last sync		*/
52	uint64_t	ub_guid_sum;	/* sum of all vdev guids	*/
53	uint64_t	ub_timestamp;	/* UTC time of last sync	*/
54	blkptr_t	ub_rootbp;	/* MOS objset_phys_t		*/
55
56	/* highest SPA_VERSION supported by software that wrote this txg */
57	uint64_t	ub_software_version;
58
59	/* These fields are reserved for features that are under development: */
60	uint64_t	ub_mmp_magic;
61	uint64_t	ub_mmp_delay;
62	uint64_t	ub_mmp_seq;
63
64	/*
65	 * ub_checkpoint_txg indicates two things about the current uberblock:
66	 *
67	 * 1] If it is not zero then this uberblock is a checkpoint. If it is
68	 *    zero, then this uberblock is not a checkpoint.
69	 *
70	 * 2] On checkpointed uberblocks, the value of ub_checkpoint_txg is
71	 *    the ub_txg that the uberblock had at the time we moved it to
72	 *    the MOS config.
73	 *
74	 * The field is set when we checkpoint the uberblock and continues to
75	 * hold that value even after we've rewound (unlike the ub_txg that
76	 * is reset to a higher value).
77	 *
78	 * Besides checks used to determine whether we are reopening the
79	 * pool from a checkpointed uberblock [see spa_ld_select_uberblock()],
80	 * the value of the field is used to determine which ZIL blocks have
81	 * been allocated according to the ms_sm when we are rewinding to a
82	 * checkpoint. Specifically, if blk_birth > ub_checkpoint_txg, then
83	 * the ZIL block is not allocated [see uses of spa_min_claim_txg()].
84	 */
85	uint64_t	ub_checkpoint_txg;
86};
87
88#ifdef	__cplusplus
89}
90#endif
91
92#endif	/* _SYS_UBERBLOCK_IMPL_H */
93