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| 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 | +#include <linux/types.h> |
| 19 | + |
| 20 | +/* |
| 21 | + * RAID superblock. |
| 22 | + * |
| 23 | + * The RAID superblock maintains some statistics on each RAID configuration. |
| 24 | + * Each real device in the RAID set contains it near the end of the device. |
| 25 | + * Some of the ideas are copied from the ext2fs implementation. |
| 26 | + * |
| 27 | + * We currently use 4096 bytes as follows: |
| 28 | + * |
| 29 | + * word offset function |
| 30 | + * |
| 31 | + * 0 - 31 Constant generic RAID device information. |
| 32 | + * 32 - 63 Generic state information. |
| 33 | + * 64 - 127 Personality specific information. |
| 34 | + * 128 - 511 12 32-words descriptors of the disks in the raid set. |
| 35 | + * 512 - 911 Reserved. |
| 36 | + * 912 - 1023 Disk specific descriptor. |
| 37 | + */ |
| 38 | + |
| 39 | +/* |
| 40 | + * If x is the real device size in bytes, we return an apparent size of: |
| 41 | + * |
| 42 | + * y = (x & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES |
| 43 | + * |
| 44 | + * and place the 4kB superblock at offset y. |
| 45 | + */ |
| 46 | +#define MD_RESERVED_BYTES (64 * 1024) |
| 47 | +#define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512) |
| 48 | + |
| 49 | +#define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS) |
| 50 | + |
| 51 | +#define MD_SB_BYTES 4096 |
| 52 | +#define MD_SB_WORDS (MD_SB_BYTES / 4) |
| 53 | +#define MD_SB_SECTORS (MD_SB_BYTES / 512) |
| 54 | + |
| 55 | +/* |
| 56 | + * The following are counted in 32-bit words |
| 57 | + */ |
| 58 | +#define MD_SB_GENERIC_OFFSET 0 |
| 59 | +#define MD_SB_PERSONALITY_OFFSET 64 |
| 60 | +#define MD_SB_DISKS_OFFSET 128 |
| 61 | +#define MD_SB_DESCRIPTOR_OFFSET 992 |
| 62 | + |
| 63 | +#define MD_SB_GENERIC_CONSTANT_WORDS 32 |
| 64 | +#define MD_SB_GENERIC_STATE_WORDS 32 |
| 65 | +#define MD_SB_GENERIC_WORDS (MD_SB_GENERIC_CONSTANT_WORDS + MD_SB_GENERIC_STATE_WORDS) |
| 66 | +#define MD_SB_PERSONALITY_WORDS 64 |
| 67 | +#define MD_SB_DESCRIPTOR_WORDS 32 |
| 68 | +#define MD_SB_DISKS 27 |
| 69 | +#define MD_SB_DISKS_WORDS (MD_SB_DISKS*MD_SB_DESCRIPTOR_WORDS) |
| 70 | +#define MD_SB_RESERVED_WORDS (1024 - MD_SB_GENERIC_WORDS - MD_SB_PERSONALITY_WORDS - MD_SB_DISKS_WORDS - MD_SB_DESCRIPTOR_WORDS) |
| 71 | +#define MD_SB_EQUAL_WORDS (MD_SB_GENERIC_WORDS + MD_SB_PERSONALITY_WORDS + MD_SB_DISKS_WORDS) |
| 72 | + |
| 73 | +/* |
| 74 | + * Device "operational" state bits |
| 75 | + */ |
| 76 | +#define MD_DISK_FAULTY 0 /* disk is faulty / operational */ |
| 77 | +#define MD_DISK_ACTIVE 1 /* disk is running or spare disk */ |
| 78 | +#define MD_DISK_SYNC 2 /* disk is in sync with the raid set */ |
| 79 | +#define MD_DISK_REMOVED 3 /* disk is in sync with the raid set */ |
| 80 | + |
| 81 | +#define MD_DISK_WRITEMOSTLY 9 /* disk is "write-mostly" is RAID1 config. |
| 82 | + * read requests will only be sent here in |
| 83 | + * dire need |
| 84 | + */ |
| 85 | + |
| 86 | +typedef struct mdp_device_descriptor_s { |
| 87 | + __u32 number; /* 0 Device number in the entire set */ |
| 88 | + __u32 major; /* 1 Device major number */ |
| 89 | + __u32 minor; /* 2 Device minor number */ |
| 90 | + __u32 raid_disk; /* 3 The role of the device in the raid set */ |
| 91 | + __u32 state; /* 4 Operational state */ |
| 92 | + __u32 reserved[MD_SB_DESCRIPTOR_WORDS - 5]; |
| 93 | +} mdp_disk_t; |
| 94 | + |
| 95 | +#define MD_SB_MAGIC 0xa92b4efc |
| 96 | + |
| 97 | +/* |
| 98 | + * Superblock state bits |
| 99 | + */ |
| 100 | +#define MD_SB_CLEAN 0 |
| 101 | +#define MD_SB_ERRORS 1 |
| 102 | + |
| 103 | +#define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */ |
| 104 | + |
| 105 | +/* |
| 106 | + * Notes: |
| 107 | + * - if an array is being reshaped (restriped) in order to change the |
| 108 | + * the number of active devices in the array, 'raid_disks' will be |
| 109 | + * the larger of the old and new numbers. 'delta_disks' will |
| 110 | + * be the "new - old". So if +ve, raid_disks is the new value, and |
| 111 | + * "raid_disks-delta_disks" is the old. If -ve, raid_disks is the |
| 112 | + * old value and "raid_disks+delta_disks" is the new (smaller) value. |
| 113 | + */ |
| 114 | + |
| 115 | + |
| 116 | +typedef struct mdp_superblock_s { |
| 117 | + /* |
| 118 | + * Constant generic information |
| 119 | + */ |
| 120 | + __u32 md_magic; /* 0 MD identifier */ |
| 121 | + __u32 major_version; /* 1 major version to which the set conforms */ |
| 122 | + __u32 minor_version; /* 2 minor version ... */ |
| 123 | + __u32 patch_version; /* 3 patchlevel version ... */ |
| 124 | + __u32 gvalid_words; /* 4 Number of used words in this section */ |
| 125 | + __u32 set_uuid0; /* 5 Raid set identifier */ |
| 126 | + __u32 ctime; /* 6 Creation time */ |
| 127 | + __u32 level; /* 7 Raid personality */ |
| 128 | + __u32 size; /* 8 Apparent size of each individual disk */ |
| 129 | + __u32 nr_disks; /* 9 total disks in the raid set */ |
| 130 | + __u32 raid_disks; /* 10 disks in a fully functional raid set */ |
| 131 | + __u32 md_minor; /* 11 preferred MD minor device number */ |
| 132 | + __u32 not_persistent; /* 12 does it have a persistent superblock */ |
| 133 | + __u32 set_uuid1; /* 13 Raid set identifier #2 */ |
| 134 | + __u32 set_uuid2; /* 14 Raid set identifier #3 */ |
| 135 | + __u32 set_uuid3; /* 15 Raid set identifier #4 */ |
| 136 | + __u32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 16]; |
| 137 | + |
| 138 | + /* |
| 139 | + * Generic state information |
| 140 | + */ |
| 141 | + __u32 utime; /* 0 Superblock update time */ |
| 142 | + __u32 state; /* 1 State bits (clean, ...) */ |
| 143 | + __u32 active_disks; /* 2 Number of currently active disks */ |
| 144 | + __u32 working_disks; /* 3 Number of working disks */ |
| 145 | + __u32 failed_disks; /* 4 Number of failed disks */ |
| 146 | + __u32 spare_disks; /* 5 Number of spare disks */ |
| 147 | + __u32 sb_csum; /* 6 checksum of the whole superblock */ |
| 148 | +#ifdef __BIG_ENDIAN |
| 149 | + __u32 events_hi; /* 7 high-order of superblock update count */ |
| 150 | + __u32 events_lo; /* 8 low-order of superblock update count */ |
| 151 | + __u32 cp_events_hi; /* 9 high-order of checkpoint update count */ |
| 152 | + __u32 cp_events_lo; /* 10 low-order of checkpoint update count */ |
| 153 | +#else |
| 154 | + __u32 events_lo; /* 7 low-order of superblock update count */ |
| 155 | + __u32 events_hi; /* 8 high-order of superblock update count */ |
| 156 | + __u32 cp_events_lo; /* 9 low-order of checkpoint update count */ |
| 157 | + __u32 cp_events_hi; /* 10 high-order of checkpoint update count */ |
| 158 | +#endif |
| 159 | + __u32 recovery_cp; /* 11 recovery checkpoint sector count */ |
| 160 | + /* There are only valid for minor_version > 90 */ |
| 161 | + __u64 reshape_position; /* 12,13 next address in array-space for reshape */ |
| 162 | + __u32 new_level; /* 14 new level we are reshaping to */ |
| 163 | + __u32 delta_disks; /* 15 change in number of raid_disks */ |
| 164 | + __u32 new_layout; /* 16 new layout */ |
| 165 | + __u32 new_chunk; /* 17 new chunk size (bytes) */ |
| 166 | + __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 18]; |
| 167 | + |
| 168 | + /* |
| 169 | + * Personality information |
| 170 | + */ |
| 171 | + __u32 layout; /* 0 the array's physical layout */ |
| 172 | + __u32 chunk_size; /* 1 chunk size in bytes */ |
| 173 | + __u32 root_pv; /* 2 LV root PV */ |
| 174 | + __u32 root_block; /* 3 LV root block */ |
| 175 | + __u32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 4]; |
| 176 | + |
| 177 | + /* |
| 178 | + * Disks information |
| 179 | + */ |
| 180 | + mdp_disk_t disks[MD_SB_DISKS]; |
| 181 | + |
| 182 | + /* |
| 183 | + * Reserved |
| 184 | + */ |
| 185 | + __u32 reserved[MD_SB_RESERVED_WORDS]; |
| 186 | + |
| 187 | + /* |
| 188 | + * Active descriptor |
| 189 | + */ |
| 190 | + mdp_disk_t this_disk; |
| 191 | + |
| 192 | +} mdp_super_t; |
| 193 | + |
| 194 | +static inline __u64 md_event(mdp_super_t *sb) { |
| 195 | + __u64 ev = sb->events_hi; |
| 196 | + return (ev<<32)| sb->events_lo; |
| 197 | +} |
| 198 | + |
| 199 | +#define MD_SUPERBLOCK_1_TIME_SEC_MASK ((1ULL<<40) - 1) |
| 200 | + |
| 201 | +/* |
| 202 | + * The version-1 superblock : |
| 203 | + * All numeric fields are little-endian. |
| 204 | + * |
| 205 | + * total size: 256 bytes plus 2 per device. |
| 206 | + * 1K allows 384 devices. |
| 207 | + */ |
| 208 | +struct mdp_superblock_1 { |
| 209 | + /* constant array information - 128 bytes */ |
| 210 | + __le32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */ |
| 211 | + __le32 major_version; /* 1 */ |
| 212 | + __le32 feature_map; /* bit 0 set if 'bitmap_offset' is meaningful */ |
| 213 | + __le32 pad0; /* always set to 0 when writing */ |
| 214 | + |
| 215 | + __u8 set_uuid[16]; /* user-space generated. */ |
| 216 | + char set_name[32]; /* set and interpreted by user-space */ |
| 217 | + |
| 218 | + __le64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/ |
| 219 | + __le32 level; /* -4 (multipath), -1 (linear), 0,1,4,5 */ |
| 220 | + __le32 layout; /* only for raid5 and raid10 currently */ |
| 221 | + __le64 size; /* used size of component devices, in 512byte sectors */ |
| 222 | + |
| 223 | + __le32 chunksize; /* in 512byte sectors */ |
| 224 | + __le32 raid_disks; |
| 225 | + __le32 bitmap_offset; /* sectors after start of superblock that bitmap starts |
| 226 | + * NOTE: signed, so bitmap can be before superblock |
| 227 | + * only meaningful of feature_map[0] is set. |
| 228 | + */ |
| 229 | + |
| 230 | + /* These are only valid with feature bit '4' */ |
| 231 | + __le32 new_level; /* new level we are reshaping to */ |
| 232 | + __le64 reshape_position; /* next address in array-space for reshape */ |
| 233 | + __le32 delta_disks; /* change in number of raid_disks */ |
| 234 | + __le32 new_layout; /* new layout */ |
| 235 | + __le32 new_chunk; /* new chunk size (512byte sectors) */ |
| 236 | + __le32 new_offset; /* signed number to add to data_offset in new |
| 237 | + * layout. 0 == no-change. This can be |
| 238 | + * different on each device in the array. |
| 239 | + */ |
| 240 | + |
| 241 | + /* constant this-device information - 64 bytes */ |
| 242 | + __le64 data_offset; /* sector start of data, often 0 */ |
| 243 | + __le64 data_size; /* sectors in this device that can be used for data */ |
| 244 | + __le64 super_offset; /* sector start of this superblock */ |
| 245 | + __le64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */ |
| 246 | + __le32 dev_number; /* permanent identifier of this device - not role in raid */ |
| 247 | + __le32 cnt_corrected_read; /* number of read errors that were corrected by re-writing */ |
| 248 | + __u8 device_uuid[16]; /* user-space setable, ignored by kernel */ |
| 249 | + __u8 devflags; /* per-device flags. Only one defined...*/ |
| 250 | +#define WriteMostly1 1 /* mask for writemostly flag in above */ |
| 251 | + /* Bad block log. If there are any bad blocks the feature flag is set. |
| 252 | + * If offset and size are non-zero, that space is reserved and available |
| 253 | + */ |
| 254 | + __u8 bblog_shift; /* shift from sectors to block size */ |
| 255 | + __le16 bblog_size; /* number of sectors reserved for list */ |
| 256 | + __le32 bblog_offset; /* sector offset from superblock to bblog, |
| 257 | + * signed - not unsigned */ |
| 258 | + |
| 259 | + /* array state information - 64 bytes */ |
| 260 | + __le64 utime; /* 40 bits second, 24 bits microseconds */ |
| 261 | + __le64 events; /* incremented when superblock updated */ |
| 262 | + __le64 resync_offset; /* data before this offset (from data_offset) known to be in sync */ |
| 263 | + __le32 sb_csum; /* checksum up to devs[max_dev] */ |
| 264 | + __le32 max_dev; /* size of devs[] array to consider */ |
| 265 | + __u8 pad3[64-32]; /* set to 0 when writing */ |
| 266 | + |
| 267 | + /* device state information. Indexed by dev_number. |
| 268 | + * 2 bytes per device |
| 269 | + * Note there are no per-device state flags. State information is rolled |
| 270 | + * into the 'roles' value. If a device is spare or faulty, then it doesn't |
| 271 | + * have a meaningful role. |
| 272 | + */ |
| 273 | + __le16 dev_roles[0]; /* role in array, or 0xffff for a spare, or 0xfffe for faulty */ |
| 274 | +}; |
| 275 | + |
| 276 | +/* feature_map bits */ |
| 277 | +#define MD_FEATURE_BITMAP_OFFSET 1 |
| 278 | +#define MD_FEATURE_RECOVERY_OFFSET 2 /* recovery_offset is present and |
| 279 | + * must be honoured |
| 280 | + */ |
| 281 | +#define MD_FEATURE_RESHAPE_ACTIVE 4 |
| 282 | +#define MD_FEATURE_BAD_BLOCKS 8 /* badblock list is not empty */ |
| 283 | +#define MD_FEATURE_REPLACEMENT 16 /* This device is replacing an |
| 284 | + * active device with same 'role'. |
| 285 | + * 'recovery_offset' is also set. |
| 286 | + */ |
| 287 | +#define MD_FEATURE_RESHAPE_BACKWARDS 32 /* Reshape doesn't change number |
| 288 | + * of devices, but is going |
| 289 | + * backwards anyway. |
| 290 | + */ |
| 291 | +#define MD_FEATURE_NEW_OFFSET 64 /* new_offset must be honoured */ |
| 292 | +#define MD_FEATURE_ALL (MD_FEATURE_BITMAP_OFFSET \ |
| 293 | + |MD_FEATURE_RECOVERY_OFFSET \ |
| 294 | + |MD_FEATURE_RESHAPE_ACTIVE \ |
| 295 | + |MD_FEATURE_BAD_BLOCKS \ |
| 296 | + |MD_FEATURE_REPLACEMENT \ |
| 297 | + |MD_FEATURE_RESHAPE_BACKWARDS \ |
| 298 | + |MD_FEATURE_NEW_OFFSET \ |
| 299 | + ) |
| 300 | + |
| 301 | +#endif |