module/zfs/include/sys/uberblock_impl.h

   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 #ifndef _SYS_UBERBLOCK_IMPL_H
  26 #define _SYS_UBERBLOCK_IMPL_H
  27
  28 #include <sys/uberblock.h>
  29
  30 #ifdef  __cplusplus
  31 extern "C" {
  32 #endif
  33
  34 /*
  35  * The uberblock version is incremented whenever an incompatible on-disk
  36  * format change is made to the SPA, DMU, or ZAP.
  37  *
  38  * Note: the first two fields should never be moved.  When a storage pool
  39  * is opened, the uberblock must be read off the disk before the version
  40  * can be checked.  If the ub_version field is moved, we may not detect
  41  * version mismatch.  If the ub_magic field is moved, applications that
  42  * expect the magic number in the first word won't work.
  43  */
  44 #define UBERBLOCK_MAGIC         0x00bab10c              /* oo-ba-bloc!  */
  45 #define UBERBLOCK_SHIFT         10                      /* up to 1K     */
  46
  47 struct uberblock {
  48         uint64_t        ub_magic;       /* UBERBLOCK_MAGIC              */
  49         uint64_t        ub_version;     /* SPA_VERSION                  */
  50         uint64_t        ub_txg;         /* txg of last sync             */
  51         uint64_t        ub_guid_sum;    /* sum of all vdev guids        */
  52         uint64_t        ub_timestamp;   /* UTC time of last sync        */
  53         blkptr_t        ub_rootbp;      /* MOS objset_phys_t            */
  54
  55         /* highest SPA_VERSION supported by software that wrote this txg */
  56         uint64_t        ub_software_version;
  57 };
  58
  59 #ifdef  __cplusplus
  60 }
  61 #endif
  62
  63 #endif  /* _SYS_UBERBLOCK_IMPL_H */