1 /* 2 * GRUB -- GRand Unified Bootloader 3 * Copyright (C) 1999,2000,2001,2002,2003,2004 Free Software Foundation, Inc. 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 /* 8 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 9 * Use is subject to license terms. 10 */ 11 12 #ifndef _SYS_UBERBLOCK_IMPL_H 13 #define _SYS_UBERBLOCK_IMPL_H 14 15 #define UBMAX(a, b) ((a) > (b) ? (a) : (b)) 16 17 /* 18 * The uberblock version is incremented whenever an incompatible on-disk 19 * format change is made to the SPA, DMU, or ZAP. 20 * 21 * Note: the first two fields should never be moved. When a storage pool 22 * is opened, the uberblock must be read off the disk before the version 23 * can be checked. If the ub_version field is moved, we may not detect 24 * version mismatch. If the ub_magic field is moved, applications that 25 * expect the magic number in the first word won't work. 26 */ 27 #define UBERBLOCK_MAGIC 0x00bab10c /* oo-ba-bloc! */ 28 #define UBERBLOCK_SHIFT 10 /* up to 1K */ 29 30 typedef struct uberblock { 31 uint64_t ub_magic; /* UBERBLOCK_MAGIC */ 32 uint64_t ub_version; /* ZFS_VERSION */ 33 uint64_t ub_txg; /* txg of last sync */ 34 uint64_t ub_guid_sum; /* sum of all vdev guids */ 35 uint64_t ub_timestamp; /* UTC time of last sync */ 36 blkptr_t ub_rootbp; /* MOS objset_phys_t */ 37 } uberblock_t; 38 39 #define VDEV_UBERBLOCK_SHIFT(as) UBMAX(as, UBERBLOCK_SHIFT) 40 #define UBERBLOCK_SIZE(as) (1ULL << VDEV_UBERBLOCK_SHIFT(as)) 41 42 /* Number of uberblocks that can fit in the ring at a given ashift */ 43 #define UBERBLOCK_COUNT(as) (VDEV_UBERBLOCK_RING >> VDEV_UBERBLOCK_SHIFT(as)) 44 45 #endif /* _SYS_UBERBLOCK_IMPL_H */ 46