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#include <asm/byteorder.h> 20 21/* 22 * RAID superblock. 23 * 24 * The RAID superblock maintains some statistics on each RAID configuration. 25 * Each real device in the RAID set contains it near the end of the device. 26 * Some of the ideas are copied from the ext2fs implementation. 27 * 28 * We currently use 4096 bytes as follows: 29 * 30 * word offset function 31 * 32 * 0 - 31 Constant generic RAID device information. 33 * 32 - 63 Generic state information. 34 * 64 - 127 Personality specific information. 35 * 128 - 511 12 32-words descriptors of the disks in the raid set. 36 * 512 - 911 Reserved. 37 * 912 - 1023 Disk specific descriptor. 38 */ 39 40/* 41 * If x is the real device size in bytes, we return an apparent size of: 42 * 43 * y = (x & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES 44 * 45 * and place the 4kB superblock at offset y. 46 */ 47#define MD_RESERVED_BYTES (64 * 1024) 48#define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512) 49 50#define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS) 51 52#define MD_SB_BYTES 4096 53#define MD_SB_WORDS (MD_SB_BYTES / 4) 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#define MD_DISK_CLUSTER_ADD 4 /* Initiate a disk add across the cluster 82 * For clustered enviroments only. 83 */ 84#define MD_DISK_CANDIDATE 5 /* disk is added as spare (local) until confirmed 85 * For clustered enviroments only. 86 */ 87 88#define MD_DISK_WRITEMOSTLY 9 /* disk is "write-mostly" is RAID1 config. 89 * read requests will only be sent here in 90 * dire need 91 */ 92#define MD_DISK_JOURNAL 18 /* disk is used as the write journal in RAID-5/6 */ 93 94#define MD_DISK_ROLE_SPARE 0xffff 95#define MD_DISK_ROLE_FAULTY 0xfffe 96#define MD_DISK_ROLE_JOURNAL 0xfffd 97#define MD_DISK_ROLE_MAX 0xff00 /* max value of regular disk role */ 98 99typedef struct mdp_device_descriptor_s { 100 __u32 number; /* 0 Device number in the entire set */ 101 __u32 major; /* 1 Device major number */ 102 __u32 minor; /* 2 Device minor number */ 103 __u32 raid_disk; /* 3 The role of the device in the raid set */ 104 __u32 state; /* 4 Operational state */ 105 __u32 reserved[MD_SB_DESCRIPTOR_WORDS - 5]; 106} mdp_disk_t; 107 108#define MD_SB_MAGIC 0xa92b4efc 109 110/* 111 * Superblock state bits 112 */ 113#define MD_SB_CLEAN 0 114#define MD_SB_ERRORS 1 115 116#define MD_SB_CLUSTERED 5 /* MD is clustered */ 117#define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */ 118 119/* 120 * Notes: 121 * - if an array is being reshaped (restriped) in order to change the 122 * the number of active devices in the array, 'raid_disks' will be 123 * the larger of the old and new numbers. 'delta_disks' will 124 * be the "new - old". So if +ve, raid_disks is the new value, and 125 * "raid_disks-delta_disks" is the old. If -ve, raid_disks is the 126 * old value and "raid_disks+delta_disks" is the new (smaller) value. 127 */ 128 129 130typedef struct mdp_superblock_s { 131 /* 132 * Constant generic information 133 */ 134 __u32 md_magic; /* 0 MD identifier */ 135 __u32 major_version; /* 1 major version to which the set conforms */ 136 __u32 minor_version; /* 2 minor version ... */ 137 __u32 patch_version; /* 3 patchlevel version ... */ 138 __u32 gvalid_words; /* 4 Number of used words in this section */ 139 __u32 set_uuid0; /* 5 Raid set identifier */ 140 __u32 ctime; /* 6 Creation time */ 141 __u32 level; /* 7 Raid personality */ 142 __u32 size; /* 8 Apparent size of each individual disk */ 143 __u32 nr_disks; /* 9 total disks in the raid set */ 144 __u32 raid_disks; /* 10 disks in a fully functional raid set */ 145 __u32 md_minor; /* 11 preferred MD minor device number */ 146 __u32 not_persistent; /* 12 does it have a persistent superblock */ 147 __u32 set_uuid1; /* 13 Raid set identifier #2 */ 148 __u32 set_uuid2; /* 14 Raid set identifier #3 */ 149 __u32 set_uuid3; /* 15 Raid set identifier #4 */ 150 __u32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 16]; 151 152 /* 153 * Generic state information 154 */ 155 __u32 utime; /* 0 Superblock update time */ 156 __u32 state; /* 1 State bits (clean, ...) */ 157 __u32 active_disks; /* 2 Number of currently active disks */ 158 __u32 working_disks; /* 3 Number of working disks */ 159 __u32 failed_disks; /* 4 Number of failed disks */ 160 __u32 spare_disks; /* 5 Number of spare disks */ 161 __u32 sb_csum; /* 6 checksum of the whole superblock */ 162#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN) 163 __u32 events_hi; /* 7 high-order of superblock update count */ 164 __u32 events_lo; /* 8 low-order of superblock update count */ 165 __u32 cp_events_hi; /* 9 high-order of checkpoint update count */ 166 __u32 cp_events_lo; /* 10 low-order of checkpoint update count */ 167#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN) 168 __u32 events_lo; /* 7 low-order of superblock update count */ 169 __u32 events_hi; /* 8 high-order of superblock update count */ 170 __u32 cp_events_lo; /* 9 low-order of checkpoint update count */ 171 __u32 cp_events_hi; /* 10 high-order of checkpoint update count */ 172#else 173#error unspecified endianness 174#endif 175 __u32 recovery_cp; /* 11 recovery checkpoint sector count */ 176 /* There are only valid for minor_version > 90 */ 177 __u64 reshape_position; /* 12,13 next address in array-space for reshape */ 178 __u32 new_level; /* 14 new level we are reshaping to */ 179 __u32 delta_disks; /* 15 change in number of raid_disks */ 180 __u32 new_layout; /* 16 new layout */ 181 __u32 new_chunk; /* 17 new chunk size (bytes) */ 182 __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 18]; 183 184 /* 185 * Personality information 186 */ 187 __u32 layout; /* 0 the array's physical layout */ 188 __u32 chunk_size; /* 1 chunk size in bytes */ 189 __u32 root_pv; /* 2 LV root PV */ 190 __u32 root_block; /* 3 LV root block */ 191 __u32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 4]; 192 193 /* 194 * Disks information 195 */ 196 mdp_disk_t disks[MD_SB_DISKS]; 197 198 /* 199 * Reserved 200 */ 201 __u32 reserved[MD_SB_RESERVED_WORDS]; 202 203 /* 204 * Active descriptor 205 */ 206 mdp_disk_t this_disk; 207 208} mdp_super_t; 209 210static inline __u64 md_event(mdp_super_t *sb) { 211 __u64 ev = sb->events_hi; 212 return (ev<<32)| sb->events_lo; 213} 214 215#define MD_SUPERBLOCK_1_TIME_SEC_MASK ((1ULL<<40) - 1) 216 217/* 218 * The version-1 superblock : 219 * All numeric fields are little-endian. 220 * 221 * total size: 256 bytes plus 2 per device. 222 * 1K allows 384 devices. 223 */ 224struct mdp_superblock_1 { 225 /* constant array information - 128 bytes */ 226 __le32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */ 227 __le32 major_version; /* 1 */ 228 __le32 feature_map; /* bit 0 set if 'bitmap_offset' is meaningful */ 229 __le32 pad0; /* always set to 0 when writing */ 230 231 __u8 set_uuid[16]; /* user-space generated. */ 232 char set_name[32]; /* set and interpreted by user-space */ 233 234 __le64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/ 235 __le32 level; /* -4 (multipath), -1 (linear), 0,1,4,5 */ 236 __le32 layout; /* only for raid5 and raid10 currently */ 237 __le64 size; /* used size of component devices, in 512byte sectors */ 238 239 __le32 chunksize; /* in 512byte sectors */ 240 __le32 raid_disks; 241 __le32 bitmap_offset; /* sectors after start of superblock that bitmap starts 242 * NOTE: signed, so bitmap can be before superblock 243 * only meaningful of feature_map[0] is set. 244 */ 245 246 /* These are only valid with feature bit '4' */ 247 __le32 new_level; /* new level we are reshaping to */ 248 __le64 reshape_position; /* next address in array-space for reshape */ 249 __le32 delta_disks; /* change in number of raid_disks */ 250 __le32 new_layout; /* new layout */ 251 __le32 new_chunk; /* new chunk size (512byte sectors) */ 252 __le32 new_offset; /* signed number to add to data_offset in new 253 * layout. 0 == no-change. This can be 254 * different on each device in the array. 255 */ 256 257 /* constant this-device information - 64 bytes */ 258 __le64 data_offset; /* sector start of data, often 0 */ 259 __le64 data_size; /* sectors in this device that can be used for data */ 260 __le64 super_offset; /* sector start of this superblock */ 261 union { 262 __le64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */ 263 __le64 journal_tail;/* journal tail of journal device (from data_offset) */ 264 }; 265 __le32 dev_number; /* permanent identifier of this device - not role in raid */ 266 __le32 cnt_corrected_read; /* number of read errors that were corrected by re-writing */ 267 __u8 device_uuid[16]; /* user-space setable, ignored by kernel */ 268 __u8 devflags; /* per-device flags. Only one defined...*/ 269#define WriteMostly1 1 /* mask for writemostly flag in above */ 270 /* Bad block log. If there are any bad blocks the feature flag is set. 271 * If offset and size are non-zero, that space is reserved and available 272 */ 273 __u8 bblog_shift; /* shift from sectors to block size */ 274 __le16 bblog_size; /* number of sectors reserved for list */ 275 __le32 bblog_offset; /* sector offset from superblock to bblog, 276 * signed - not unsigned */ 277 278 /* array state information - 64 bytes */ 279 __le64 utime; /* 40 bits second, 24 bits microseconds */ 280 __le64 events; /* incremented when superblock updated */ 281 __le64 resync_offset; /* data before this offset (from data_offset) known to be in sync */ 282 __le32 sb_csum; /* checksum up to devs[max_dev] */ 283 __le32 max_dev; /* size of devs[] array to consider */ 284 __u8 pad3[64-32]; /* set to 0 when writing */ 285 286 /* device state information. Indexed by dev_number. 287 * 2 bytes per device 288 * Note there are no per-device state flags. State information is rolled 289 * into the 'roles' value. If a device is spare or faulty, then it doesn't 290 * have a meaningful role. 291 */ 292 __le16 dev_roles[0]; /* role in array, or 0xffff for a spare, or 0xfffe for faulty */ 293}; 294 295/* feature_map bits */ 296#define MD_FEATURE_BITMAP_OFFSET 1 297#define MD_FEATURE_RECOVERY_OFFSET 2 /* recovery_offset is present and 298 * must be honoured 299 */ 300#define MD_FEATURE_RESHAPE_ACTIVE 4 301#define MD_FEATURE_BAD_BLOCKS 8 /* badblock list is not empty */ 302#define MD_FEATURE_REPLACEMENT 16 /* This device is replacing an 303 * active device with same 'role'. 304 * 'recovery_offset' is also set. 305 */ 306#define MD_FEATURE_RESHAPE_BACKWARDS 32 /* Reshape doesn't change number 307 * of devices, but is going 308 * backwards anyway. 309 */ 310#define MD_FEATURE_NEW_OFFSET 64 /* new_offset must be honoured */ 311#define MD_FEATURE_RECOVERY_BITMAP 128 /* recovery that is happening 312 * is guided by bitmap. 313 */ 314#define MD_FEATURE_CLUSTERED 256 /* clustered MD */ 315#define MD_FEATURE_JOURNAL 512 /* support write cache */ 316#define MD_FEATURE_ALL (MD_FEATURE_BITMAP_OFFSET \ 317 |MD_FEATURE_RECOVERY_OFFSET \ 318 |MD_FEATURE_RESHAPE_ACTIVE \ 319 |MD_FEATURE_BAD_BLOCKS \ 320 |MD_FEATURE_REPLACEMENT \ 321 |MD_FEATURE_RESHAPE_BACKWARDS \ 322 |MD_FEATURE_NEW_OFFSET \ 323 |MD_FEATURE_RECOVERY_BITMAP \ 324 |MD_FEATURE_CLUSTERED \ 325 |MD_FEATURE_JOURNAL \ 326 ) 327 328struct r5l_payload_header { 329 __le16 type; 330 __le16 flags; 331} __attribute__ ((__packed__)); 332 333enum r5l_payload_type { 334 R5LOG_PAYLOAD_DATA = 0, 335 R5LOG_PAYLOAD_PARITY = 1, 336 R5LOG_PAYLOAD_FLUSH = 2, 337}; 338 339struct r5l_payload_data_parity { 340 struct r5l_payload_header header; 341 __le32 size; /* sector. data/parity size. each 4k 342 * has a checksum */ 343 __le64 location; /* sector. For data, it's raid sector. For 344 * parity, it's stripe sector */ 345 __le32 checksum[]; 346} __attribute__ ((__packed__)); 347 348enum r5l_payload_data_parity_flag { 349 R5LOG_PAYLOAD_FLAG_DISCARD = 1, /* payload is discard */ 350 /* 351 * RESHAPED/RESHAPING is only set when there is reshape activity. Note, 352 * both data/parity of a stripe should have the same flag set 353 * 354 * RESHAPED: reshape is running, and this stripe finished reshape 355 * RESHAPING: reshape is running, and this stripe isn't reshaped 356 */ 357 R5LOG_PAYLOAD_FLAG_RESHAPED = 2, 358 R5LOG_PAYLOAD_FLAG_RESHAPING = 3, 359}; 360 361struct r5l_payload_flush { 362 struct r5l_payload_header header; 363 __le32 size; /* flush_stripes size, bytes */ 364 __le64 flush_stripes[]; 365} __attribute__ ((__packed__)); 366 367enum r5l_payload_flush_flag { 368 R5LOG_PAYLOAD_FLAG_FLUSH_STRIPE = 1, /* data represents whole stripe */ 369}; 370 371struct r5l_meta_block { 372 __le32 magic; 373 __le32 checksum; 374 __u8 version; 375 __u8 __zero_pading_1; 376 __le16 __zero_pading_2; 377 __le32 meta_size; /* whole size of the block */ 378 379 __le64 seq; 380 __le64 position; /* sector, start from rdev->data_offset, current position */ 381 struct r5l_payload_header payloads[]; 382} __attribute__ ((__packed__)); 383 384#define R5LOG_VERSION 0x1 385#define R5LOG_MAGIC 0x6433c509 386#endif 387