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| Rev | Author | Line No. | Line |
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| 423 | giacomo | 1 | /* |
| 2 | md_p.h : physical layout of Linux RAID devices |
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| 3 | Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman |
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| 4 | |||
| 5 | This program is free software; you can redistribute it and/or modify |
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| 6 | it under the terms of the GNU General Public License as published by |
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| 7 | the Free Software Foundation; either version 2, or (at your option) |
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| 8 | any later version. |
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| 9 | |||
| 10 | You should have received a copy of the GNU General Public License |
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| 11 | (for example /usr/src/linux/COPYING); if not, write to the Free |
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| 12 | Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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| 13 | */ |
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| 14 | |||
| 15 | #ifndef _MD_P_H |
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| 16 | #define _MD_P_H |
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| 17 | |||
| 18 | /* |
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| 19 | * RAID superblock. |
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| 20 | * |
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| 21 | * The RAID superblock maintains some statistics on each RAID configuration. |
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| 22 | * Each real device in the RAID set contains it near the end of the device. |
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| 23 | * Some of the ideas are copied from the ext2fs implementation. |
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| 24 | * |
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| 25 | * We currently use 4096 bytes as follows: |
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| 26 | * |
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| 27 | * word offset function |
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| 28 | * |
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| 29 | * 0 - 31 Constant generic RAID device information. |
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| 30 | * 32 - 63 Generic state information. |
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| 31 | * 64 - 127 Personality specific information. |
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| 32 | * 128 - 511 12 32-words descriptors of the disks in the raid set. |
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| 33 | * 512 - 911 Reserved. |
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| 34 | * 912 - 1023 Disk specific descriptor. |
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| 35 | */ |
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| 36 | |||
| 37 | /* |
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| 38 | * If x is the real device size in bytes, we return an apparent size of: |
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| 39 | * |
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| 40 | * y = (x & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES |
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| 41 | * |
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| 42 | * and place the 4kB superblock at offset y. |
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| 43 | */ |
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| 44 | #define MD_RESERVED_BYTES (64 * 1024) |
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| 45 | #define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512) |
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| 46 | #define MD_RESERVED_BLOCKS (MD_RESERVED_BYTES / BLOCK_SIZE) |
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| 47 | |||
| 48 | #define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS) |
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| 49 | #define MD_NEW_SIZE_BLOCKS(x) ((x & ~(MD_RESERVED_BLOCKS - 1)) - MD_RESERVED_BLOCKS) |
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| 50 | |||
| 51 | #define MD_SB_BYTES 4096 |
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| 52 | #define MD_SB_WORDS (MD_SB_BYTES / 4) |
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| 53 | #define MD_SB_BLOCKS (MD_SB_BYTES / BLOCK_SIZE) |
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| 54 | #define MD_SB_SECTORS (MD_SB_BYTES / 512) |
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| 55 | |||
| 56 | /* |
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| 57 | * The following are counted in 32-bit words |
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| 58 | */ |
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| 59 | #define MD_SB_GENERIC_OFFSET 0 |
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| 60 | #define MD_SB_PERSONALITY_OFFSET 64 |
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| 61 | #define MD_SB_DISKS_OFFSET 128 |
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| 62 | #define MD_SB_DESCRIPTOR_OFFSET 992 |
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| 63 | |||
| 64 | #define MD_SB_GENERIC_CONSTANT_WORDS 32 |
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| 65 | #define MD_SB_GENERIC_STATE_WORDS 32 |
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| 66 | #define MD_SB_GENERIC_WORDS (MD_SB_GENERIC_CONSTANT_WORDS + MD_SB_GENERIC_STATE_WORDS) |
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| 67 | #define MD_SB_PERSONALITY_WORDS 64 |
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| 68 | #define MD_SB_DESCRIPTOR_WORDS 32 |
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| 69 | #define MD_SB_DISKS 27 |
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| 70 | #define MD_SB_DISKS_WORDS (MD_SB_DISKS*MD_SB_DESCRIPTOR_WORDS) |
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| 71 | #define MD_SB_RESERVED_WORDS (1024 - MD_SB_GENERIC_WORDS - MD_SB_PERSONALITY_WORDS - MD_SB_DISKS_WORDS - MD_SB_DESCRIPTOR_WORDS) |
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| 72 | #define MD_SB_EQUAL_WORDS (MD_SB_GENERIC_WORDS + MD_SB_PERSONALITY_WORDS + MD_SB_DISKS_WORDS) |
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| 73 | |||
| 74 | /* |
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| 75 | * Device "operational" state bits |
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| 76 | */ |
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| 77 | #define MD_DISK_FAULTY 0 /* disk is faulty / operational */ |
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| 78 | #define MD_DISK_ACTIVE 1 /* disk is running or spare disk */ |
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| 79 | #define MD_DISK_SYNC 2 /* disk is in sync with the raid set */ |
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| 80 | #define MD_DISK_REMOVED 3 /* disk is in sync with the raid set */ |
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| 81 | |||
| 82 | typedef struct mdp_device_descriptor_s { |
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| 83 | __u32 number; /* 0 Device number in the entire set */ |
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| 84 | __u32 major; /* 1 Device major number */ |
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| 85 | __u32 minor; /* 2 Device minor number */ |
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| 86 | __u32 raid_disk; /* 3 The role of the device in the raid set */ |
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| 87 | __u32 state; /* 4 Operational state */ |
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| 88 | __u32 reserved[MD_SB_DESCRIPTOR_WORDS - 5]; |
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| 89 | } mdp_disk_t; |
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| 90 | |||
| 91 | #define MD_SB_MAGIC 0xa92b4efc |
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| 92 | |||
| 93 | /* |
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| 94 | * Superblock state bits |
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| 95 | */ |
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| 96 | #define MD_SB_CLEAN 0 |
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| 97 | #define MD_SB_ERRORS 1 |
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| 98 | |||
| 99 | typedef struct mdp_superblock_s { |
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| 100 | /* |
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| 101 | * Constant generic information |
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| 102 | */ |
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| 103 | __u32 md_magic; /* 0 MD identifier */ |
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| 104 | __u32 major_version; /* 1 major version to which the set conforms */ |
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| 105 | __u32 minor_version; /* 2 minor version ... */ |
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| 106 | __u32 patch_version; /* 3 patchlevel version ... */ |
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| 107 | __u32 gvalid_words; /* 4 Number of used words in this section */ |
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| 108 | __u32 set_uuid0; /* 5 Raid set identifier */ |
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| 109 | __u32 ctime; /* 6 Creation time */ |
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| 110 | __u32 level; /* 7 Raid personality */ |
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| 111 | __u32 size; /* 8 Apparent size of each individual disk */ |
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| 112 | __u32 nr_disks; /* 9 total disks in the raid set */ |
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| 113 | __u32 raid_disks; /* 10 disks in a fully functional raid set */ |
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| 114 | __u32 md_minor; /* 11 preferred MD minor device number */ |
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| 115 | __u32 not_persistent; /* 12 does it have a persistent superblock */ |
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| 116 | __u32 set_uuid1; /* 13 Raid set identifier #2 */ |
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| 117 | __u32 set_uuid2; /* 14 Raid set identifier #3 */ |
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| 118 | __u32 set_uuid3; /* 15 Raid set identifier #4 */ |
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| 119 | __u32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 16]; |
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| 120 | |||
| 121 | /* |
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| 122 | * Generic state information |
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| 123 | */ |
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| 124 | __u32 utime; /* 0 Superblock update time */ |
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| 125 | __u32 state; /* 1 State bits (clean, ...) */ |
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| 126 | __u32 active_disks; /* 2 Number of currently active disks */ |
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| 127 | __u32 working_disks; /* 3 Number of working disks */ |
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| 128 | __u32 failed_disks; /* 4 Number of failed disks */ |
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| 129 | __u32 spare_disks; /* 5 Number of spare disks */ |
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| 130 | __u32 sb_csum; /* 6 checksum of the whole superblock */ |
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| 131 | #ifdef __BIG_ENDIAN |
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| 132 | __u32 events_hi; /* 7 high-order of superblock update count */ |
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| 133 | __u32 events_lo; /* 8 low-order of superblock update count */ |
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| 134 | __u32 cp_events_hi; /* 9 high-order of checkpoint update count */ |
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| 135 | __u32 cp_events_lo; /* 10 low-order of checkpoint update count */ |
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| 136 | #else |
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| 137 | __u32 events_lo; /* 7 low-order of superblock update count */ |
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| 138 | __u32 events_hi; /* 8 high-order of superblock update count */ |
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| 139 | __u32 cp_events_lo; /* 9 low-order of checkpoint update count */ |
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| 140 | __u32 cp_events_hi; /* 10 high-order of checkpoint update count */ |
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| 141 | #endif |
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| 142 | __u32 recovery_cp; /* 11 recovery checkpoint sector count */ |
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| 143 | __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 12]; |
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| 144 | |||
| 145 | /* |
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| 146 | * Personality information |
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| 147 | */ |
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| 148 | __u32 layout; /* 0 the array's physical layout */ |
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| 149 | __u32 chunk_size; /* 1 chunk size in bytes */ |
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| 150 | __u32 root_pv; /* 2 LV root PV */ |
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| 151 | __u32 root_block; /* 3 LV root block */ |
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| 152 | __u32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 4]; |
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| 153 | |||
| 154 | /* |
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| 155 | * Disks information |
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| 156 | */ |
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| 157 | mdp_disk_t disks[MD_SB_DISKS]; |
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| 158 | |||
| 159 | /* |
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| 160 | * Reserved |
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| 161 | */ |
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| 162 | __u32 reserved[MD_SB_RESERVED_WORDS]; |
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| 163 | |||
| 164 | /* |
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| 165 | * Active descriptor |
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| 166 | */ |
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| 167 | mdp_disk_t this_disk; |
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| 168 | |||
| 169 | } mdp_super_t; |
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| 170 | |||
| 171 | static inline __u64 md_event(mdp_super_t *sb) { |
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| 172 | __u64 ev = sb->events_hi; |
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| 173 | return (ev<<32)| sb->events_lo; |
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| 174 | } |
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| 175 | |||
| 176 | /* |
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| 177 | * The version-1 superblock : |
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| 178 | * All numeric fields are little-endian. |
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| 179 | * |
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| 180 | * total size: 256 bytes plus 2 per device. |
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| 181 | * 1K allows 384 devices. |
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| 182 | */ |
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| 183 | struct mdp_superblock_1 { |
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| 184 | /* constant array information - 128 bytes */ |
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| 185 | __u32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */ |
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| 186 | __u32 major_version; /* 1 */ |
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| 187 | __u32 feature_map; /* 0 for now */ |
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| 188 | __u32 pad0; /* always set to 0 when writing */ |
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| 189 | |||
| 190 | __u8 set_uuid[16]; /* user-space generated. */ |
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| 191 | char set_name[32]; /* set and interpreted by user-space */ |
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| 192 | |||
| 193 | __u64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/ |
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| 194 | __u32 level; /* -4 (multipath), -1 (linear), 0,1,4,5 */ |
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| 195 | __u32 layout; /* only for raid5 currently */ |
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| 196 | __u64 size; /* used size of component devices, in 512byte sectors */ |
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| 197 | |||
| 198 | __u32 chunksize; /* in 512byte sectors */ |
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| 199 | __u32 raid_disks; |
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| 200 | __u8 pad1[128-92]; /* set to 0 when written */ |
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| 201 | |||
| 202 | /* constant this-device information - 64 bytes */ |
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| 203 | __u64 data_offset; /* sector start of data, often 0 */ |
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| 204 | __u64 data_size; /* sectors in this device that can be used for data */ |
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| 205 | __u64 super_offset; /* sector start of this superblock */ |
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| 206 | __u64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */ |
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| 207 | __u32 dev_number; /* permanent identifier of this device - not role in raid */ |
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| 208 | __u32 cnt_corrected_read; /* number of read errors that were corrected by re-writing */ |
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| 209 | __u8 device_uuid[16]; /* user-space setable, ignored by kernel */ |
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| 210 | __u8 pad2[64-56]; /* set to 0 when writing */ |
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| 211 | |||
| 212 | /* array state information - 64 bytes */ |
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| 213 | __u64 utime; /* 40 bits second, 24 btes microseconds */ |
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| 214 | __u64 events; /* incremented when superblock updated */ |
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| 215 | __u64 resync_offset; /* data before this offset (from data_offset) known to be in sync */ |
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| 216 | __u32 sb_csum; /* checksum upto devs[max_dev] */ |
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| 217 | __u32 max_dev; /* size of devs[] array to consider */ |
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| 218 | __u8 pad3[64-40]; /* set to 0 when writing */ |
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| 219 | |||
| 220 | /* device state information. Indexed by dev_number. |
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| 221 | * 2 bytes per device |
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| 222 | * Note there are no per-device state flags. State information is rolled |
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| 223 | * into the 'roles' value. If a device is spare or faulty, then it doesn't |
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| 224 | * have a meaningful role. |
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| 225 | */ |
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| 226 | __u16 dev_roles[0]; /* role in array, or 0xffff for a spare, or 0xfffe for faulty */ |
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| 227 | }; |
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| 228 | |||
| 229 | #endif |
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| 230 |