1/* 2 md_p.h : physical layout of Linux RAID devices 3 Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 2, or (at your option) 8 any later version. 9 10 You should have received a copy of the GNU General Public License 11 (for example /usr/src/linux/COPYING); if not, write to the Free 12 Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 13*/ 14 15#ifndef _MD_P_H 16#define _MD_P_H 17 18/* 19 * RAID superblock. 20 * 21 * The RAID superblock maintains some statistics on each RAID configuration. 22 * Each real device in the RAID set contains it near the end of the device. 23 * Some of the ideas are copied from the ext2fs implementation. 24 * 25 * We currently use 4096 bytes as follows: 26 * 27 * word offset function 28 * 29 * 0 - 31 Constant generic RAID device information. 30 * 32 - 63 Generic state information. 31 * 64 - 127 Personality specific information. 32 * 128 - 511 12 32-words descriptors of the disks in the raid set. 33 * 512 - 911 Reserved. 34 * 912 - 1023 Disk specific descriptor. 35 */ 36 37/* 38 * If x is the real device size in bytes, we return an apparent size of: 39 * 40 * y = (x & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES 41 * 42 * and place the 4kB superblock at offset y. 43 */ 44#define MD_RESERVED_BYTES (64 * 1024) 45#define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512) 46#define MD_RESERVED_BLOCKS (MD_RESERVED_BYTES / BLOCK_SIZE) 47 48#define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS) 49#define MD_NEW_SIZE_BLOCKS(x) ((x & ~(MD_RESERVED_BLOCKS - 1)) - MD_RESERVED_BLOCKS) 50 51#define MD_SB_BYTES 4096 52#define MD_SB_WORDS (MD_SB_BYTES / 4) 53#define MD_SB_BLOCKS (MD_SB_BYTES / BLOCK_SIZE) 54#define MD_SB_SECTORS (MD_SB_BYTES / 512) 55 56/* 57 * The following are counted in 32-bit words 58 */ 59#define MD_SB_GENERIC_OFFSET 0 60#define MD_SB_PERSONALITY_OFFSET 64 61#define MD_SB_DISKS_OFFSET 128 62#define MD_SB_DESCRIPTOR_OFFSET 992 63 64#define MD_SB_GENERIC_CONSTANT_WORDS 32 65#define MD_SB_GENERIC_STATE_WORDS 32 66#define MD_SB_GENERIC_WORDS (MD_SB_GENERIC_CONSTANT_WORDS + MD_SB_GENERIC_STATE_WORDS) 67#define MD_SB_PERSONALITY_WORDS 64 68#define MD_SB_DESCRIPTOR_WORDS 32 69#define MD_SB_DISKS 27 70#define MD_SB_DISKS_WORDS (MD_SB_DISKS*MD_SB_DESCRIPTOR_WORDS) 71#define MD_SB_RESERVED_WORDS (1024 - MD_SB_GENERIC_WORDS - MD_SB_PERSONALITY_WORDS - MD_SB_DISKS_WORDS - MD_SB_DESCRIPTOR_WORDS) 72#define MD_SB_EQUAL_WORDS (MD_SB_GENERIC_WORDS + MD_SB_PERSONALITY_WORDS + MD_SB_DISKS_WORDS) 73 74/* 75 * Device "operational" state bits 76 */ 77#define MD_DISK_FAULTY 0 /* disk is faulty / operational */ 78#define MD_DISK_ACTIVE 1 /* disk is running or spare disk */ 79#define MD_DISK_SYNC 2 /* disk is in sync with the raid set */ 80#define MD_DISK_REMOVED 3 /* disk is in sync with the raid set */ 81 82typedef struct mdp_device_descriptor_s { 83 __u32 number; /* 0 Device number in the entire set */ 84 __u32 major; /* 1 Device major number */ 85 __u32 minor; /* 2 Device minor number */ 86 __u32 raid_disk; /* 3 The role of the device in the raid set */ 87 __u32 state; /* 4 Operational state */ 88 __u32 reserved[MD_SB_DESCRIPTOR_WORDS - 5]; 89} mdp_disk_t; 90 91#define MD_SB_MAGIC 0xa92b4efc 92 93/* 94 * Superblock state bits 95 */ 96#define MD_SB_CLEAN 0 97#define MD_SB_ERRORS 1 98 99typedef struct mdp_superblock_s { 100 /* 101 * Constant generic information 102 */ 103 __u32 md_magic; /* 0 MD identifier */ 104 __u32 major_version; /* 1 major version to which the set conforms */ 105 __u32 minor_version; /* 2 minor version ... */ 106 __u32 patch_version; /* 3 patchlevel version ... */ 107 __u32 gvalid_words; /* 4 Number of used words in this section */ 108 __u32 set_uuid0; /* 5 Raid set identifier */ 109 __u32 ctime; /* 6 Creation time */ 110 __u32 level; /* 7 Raid personality */ 111 __u32 size; /* 8 Apparent size of each individual disk */ 112 __u32 nr_disks; /* 9 total disks in the raid set */ 113 __u32 raid_disks; /* 10 disks in a fully functional raid set */ 114 __u32 md_minor; /* 11 preferred MD minor device number */ 115 __u32 not_persistent; /* 12 does it have a persistent superblock */ 116 __u32 set_uuid1; /* 13 Raid set identifier #2 */ 117 __u32 set_uuid2; /* 14 Raid set identifier #3 */ 118 __u32 set_uuid3; /* 15 Raid set identifier #4 */ 119 __u32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 16]; 120 121 /* 122 * Generic state information 123 */ 124 __u32 utime; /* 0 Superblock update time */ 125 __u32 state; /* 1 State bits (clean, ...) */ 126 __u32 active_disks; /* 2 Number of currently active disks */ 127 __u32 working_disks; /* 3 Number of working disks */ 128 __u32 failed_disks; /* 4 Number of failed disks */ 129 __u32 spare_disks; /* 5 Number of spare disks */ 130 __u32 sb_csum; /* 6 checksum of the whole superblock */ 131#ifdef __BIG_ENDIAN 132 __u32 events_hi; /* 7 high-order of superblock update count */ 133 __u32 events_lo; /* 8 low-order of superblock update count */ 134#else 135 __u32 events_lo; /* 7 low-order of superblock update count */ 136 __u32 events_hi; /* 8 high-order of superblock update count */ 137#endif 138 __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 9]; 139 140 /* 141 * Personality information 142 */ 143 __u32 layout; /* 0 the array's physical layout */ 144 __u32 chunk_size; /* 1 chunk size in bytes */ 145 __u32 root_pv; /* 2 LV root PV */ 146 __u32 root_block; /* 3 LV root block */ 147 __u32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 4]; 148 149 /* 150 * Disks information 151 */ 152 mdp_disk_t disks[MD_SB_DISKS]; 153 154 /* 155 * Reserved 156 */ 157 __u32 reserved[MD_SB_RESERVED_WORDS]; 158 159 /* 160 * Active descriptor 161 */ 162 mdp_disk_t this_disk; 163 164} mdp_super_t; 165 166static inline __u64 md_event(mdp_super_t *sb) { 167 __u64 ev = sb->events_hi; 168 return (ev<<32)| sb->events_lo; 169} 170 171#endif 172 173