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 #define MD_DISK_FAILFAST 10 /* Send REQ_FAILFAST if there are multiple 88 * devices available - and don't try to 89 * correct read errors. 90 */ 91 92 #define MD_DISK_WRITEMOSTLY 9 /* disk is "write-mostly" is RAID1 config. 93 * read requests will only be sent here in 94 * dire need 95 */ 96 #define MD_DISK_JOURNAL 18 /* disk is used as the write journal in RAID-5/6 */ 97 98 #define MD_DISK_ROLE_SPARE 0xffff 99 #define MD_DISK_ROLE_FAULTY 0xfffe 100 #define MD_DISK_ROLE_JOURNAL 0xfffd 101 #define MD_DISK_ROLE_MAX 0xff00 /* max value of regular disk role */ 102 103 typedef struct mdp_device_descriptor_s { 104 __u32 number; /* 0 Device number in the entire set */ 105 __u32 major; /* 1 Device major number */ 106 __u32 minor; /* 2 Device minor number */ 107 __u32 raid_disk; /* 3 The role of the device in the raid set */ 108 __u32 state; /* 4 Operational state */ 109 __u32 reserved[MD_SB_DESCRIPTOR_WORDS - 5]; 110 } mdp_disk_t; 111 112 #define MD_SB_MAGIC 0xa92b4efc 113 114 /* 115 * Superblock state bits 116 */ 117 #define MD_SB_CLEAN 0 118 #define MD_SB_ERRORS 1 119 120 #define MD_SB_CLUSTERED 5 /* MD is clustered */ 121 #define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */ 122 123 /* 124 * Notes: 125 * - if an array is being reshaped (restriped) in order to change the 126 * the number of active devices in the array, 'raid_disks' will be 127 * the larger of the old and new numbers. 'delta_disks' will 128 * be the "new - old". So if +ve, raid_disks is the new value, and 129 * "raid_disks-delta_disks" is the old. If -ve, raid_disks is the 130 * old value and "raid_disks+delta_disks" is the new (smaller) value. 131 */ 132 133 134 typedef struct mdp_superblock_s { 135 /* 136 * Constant generic information 137 */ 138 __u32 md_magic; /* 0 MD identifier */ 139 __u32 major_version; /* 1 major version to which the set conforms */ 140 __u32 minor_version; /* 2 minor version ... */ 141 __u32 patch_version; /* 3 patchlevel version ... */ 142 __u32 gvalid_words; /* 4 Number of used words in this section */ 143 __u32 set_uuid0; /* 5 Raid set identifier */ 144 __u32 ctime; /* 6 Creation time */ 145 __u32 level; /* 7 Raid personality */ 146 __u32 size; /* 8 Apparent size of each individual disk */ 147 __u32 nr_disks; /* 9 total disks in the raid set */ 148 __u32 raid_disks; /* 10 disks in a fully functional raid set */ 149 __u32 md_minor; /* 11 preferred MD minor device number */ 150 __u32 not_persistent; /* 12 does it have a persistent superblock */ 151 __u32 set_uuid1; /* 13 Raid set identifier #2 */ 152 __u32 set_uuid2; /* 14 Raid set identifier #3 */ 153 __u32 set_uuid3; /* 15 Raid set identifier #4 */ 154 __u32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 16]; 155 156 /* 157 * Generic state information 158 */ 159 __u32 utime; /* 0 Superblock update time */ 160 __u32 state; /* 1 State bits (clean, ...) */ 161 __u32 active_disks; /* 2 Number of currently active disks */ 162 __u32 working_disks; /* 3 Number of working disks */ 163 __u32 failed_disks; /* 4 Number of failed disks */ 164 __u32 spare_disks; /* 5 Number of spare disks */ 165 __u32 sb_csum; /* 6 checksum of the whole superblock */ 166 #if defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN) 167 __u32 events_hi; /* 7 high-order of superblock update count */ 168 __u32 events_lo; /* 8 low-order of superblock update count */ 169 __u32 cp_events_hi; /* 9 high-order of checkpoint update count */ 170 __u32 cp_events_lo; /* 10 low-order of checkpoint update count */ 171 #elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN) 172 __u32 events_lo; /* 7 low-order of superblock update count */ 173 __u32 events_hi; /* 8 high-order of superblock update count */ 174 __u32 cp_events_lo; /* 9 low-order of checkpoint update count */ 175 __u32 cp_events_hi; /* 10 high-order of checkpoint update count */ 176 #else 177 #error unspecified endianness 178 #endif 179 __u32 recovery_cp; /* 11 recovery checkpoint sector count */ 180 /* There are only valid for minor_version > 90 */ 181 __u64 reshape_position; /* 12,13 next address in array-space for reshape */ 182 __u32 new_level; /* 14 new level we are reshaping to */ 183 __u32 delta_disks; /* 15 change in number of raid_disks */ 184 __u32 new_layout; /* 16 new layout */ 185 __u32 new_chunk; /* 17 new chunk size (bytes) */ 186 __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 18]; 187 188 /* 189 * Personality information 190 */ 191 __u32 layout; /* 0 the array's physical layout */ 192 __u32 chunk_size; /* 1 chunk size in bytes */ 193 __u32 root_pv; /* 2 LV root PV */ 194 __u32 root_block; /* 3 LV root block */ 195 __u32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 4]; 196 197 /* 198 * Disks information 199 */ 200 mdp_disk_t disks[MD_SB_DISKS]; 201 202 /* 203 * Reserved 204 */ 205 __u32 reserved[MD_SB_RESERVED_WORDS]; 206 207 /* 208 * Active descriptor 209 */ 210 mdp_disk_t this_disk; 211 212 } mdp_super_t; 213 214 static inline __u64 md_event(mdp_super_t *sb) { 215 __u64 ev = sb->events_hi; 216 return (ev<<32)| sb->events_lo; 217 } 218 219 #define MD_SUPERBLOCK_1_TIME_SEC_MASK ((1ULL<<40) - 1) 220 221 /* 222 * The version-1 superblock : 223 * All numeric fields are little-endian. 224 * 225 * total size: 256 bytes plus 2 per device. 226 * 1K allows 384 devices. 227 */ 228 struct mdp_superblock_1 { 229 /* constant array information - 128 bytes */ 230 __le32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */ 231 __le32 major_version; /* 1 */ 232 __le32 feature_map; /* bit 0 set if 'bitmap_offset' is meaningful */ 233 __le32 pad0; /* always set to 0 when writing */ 234 235 __u8 set_uuid[16]; /* user-space generated. */ 236 char set_name[32]; /* set and interpreted by user-space */ 237 238 __le64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/ 239 __le32 level; /* -4 (multipath), -1 (linear), 0,1,4,5 */ 240 __le32 layout; /* only for raid5 and raid10 currently */ 241 __le64 size; /* used size of component devices, in 512byte sectors */ 242 243 __le32 chunksize; /* in 512byte sectors */ 244 __le32 raid_disks; 245 union { 246 __le32 bitmap_offset; /* sectors after start of superblock that bitmap starts 247 * NOTE: signed, so bitmap can be before superblock 248 * only meaningful of feature_map[0] is set. 249 */ 250 251 /* only meaningful when feature_map[MD_FEATURE_PPL] is set */ 252 struct { 253 __le16 offset; /* sectors from start of superblock that ppl starts (signed) */ 254 __le16 size; /* ppl size in sectors */ 255 } ppl; 256 }; 257 258 /* These are only valid with feature bit '4' */ 259 __le32 new_level; /* new level we are reshaping to */ 260 __le64 reshape_position; /* next address in array-space for reshape */ 261 __le32 delta_disks; /* change in number of raid_disks */ 262 __le32 new_layout; /* new layout */ 263 __le32 new_chunk; /* new chunk size (512byte sectors) */ 264 __le32 new_offset; /* signed number to add to data_offset in new 265 * layout. 0 == no-change. This can be 266 * different on each device in the array. 267 */ 268 269 /* constant this-device information - 64 bytes */ 270 __le64 data_offset; /* sector start of data, often 0 */ 271 __le64 data_size; /* sectors in this device that can be used for data */ 272 __le64 super_offset; /* sector start of this superblock */ 273 union { 274 __le64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */ 275 __le64 journal_tail;/* journal tail of journal device (from data_offset) */ 276 }; 277 __le32 dev_number; /* permanent identifier of this device - not role in raid */ 278 __le32 cnt_corrected_read; /* number of read errors that were corrected by re-writing */ 279 __u8 device_uuid[16]; /* user-space setable, ignored by kernel */ 280 __u8 devflags; /* per-device flags. Only two defined...*/ 281 #define WriteMostly1 1 /* mask for writemostly flag in above */ 282 #define FailFast1 2 /* Should avoid retries and fixups and just fail */ 283 /* Bad block log. If there are any bad blocks the feature flag is set. 284 * If offset and size are non-zero, that space is reserved and available 285 */ 286 __u8 bblog_shift; /* shift from sectors to block size */ 287 __le16 bblog_size; /* number of sectors reserved for list */ 288 __le32 bblog_offset; /* sector offset from superblock to bblog, 289 * signed - not unsigned */ 290 291 /* array state information - 64 bytes */ 292 __le64 utime; /* 40 bits second, 24 bits microseconds */ 293 __le64 events; /* incremented when superblock updated */ 294 __le64 resync_offset; /* data before this offset (from data_offset) known to be in sync */ 295 __le32 sb_csum; /* checksum up to devs[max_dev] */ 296 __le32 max_dev; /* size of devs[] array to consider */ 297 __u8 pad3[64-32]; /* set to 0 when writing */ 298 299 /* device state information. Indexed by dev_number. 300 * 2 bytes per device 301 * Note there are no per-device state flags. State information is rolled 302 * into the 'roles' value. If a device is spare or faulty, then it doesn't 303 * have a meaningful role. 304 */ 305 __le16 dev_roles[0]; /* role in array, or 0xffff for a spare, or 0xfffe for faulty */ 306 }; 307 308 /* feature_map bits */ 309 #define MD_FEATURE_BITMAP_OFFSET 1 310 #define MD_FEATURE_RECOVERY_OFFSET 2 /* recovery_offset is present and 311 * must be honoured 312 */ 313 #define MD_FEATURE_RESHAPE_ACTIVE 4 314 #define MD_FEATURE_BAD_BLOCKS 8 /* badblock list is not empty */ 315 #define MD_FEATURE_REPLACEMENT 16 /* This device is replacing an 316 * active device with same 'role'. 317 * 'recovery_offset' is also set. 318 */ 319 #define MD_FEATURE_RESHAPE_BACKWARDS 32 /* Reshape doesn't change number 320 * of devices, but is going 321 * backwards anyway. 322 */ 323 #define MD_FEATURE_NEW_OFFSET 64 /* new_offset must be honoured */ 324 #define MD_FEATURE_RECOVERY_BITMAP 128 /* recovery that is happening 325 * is guided by bitmap. 326 */ 327 #define MD_FEATURE_CLUSTERED 256 /* clustered MD */ 328 #define MD_FEATURE_JOURNAL 512 /* support write cache */ 329 #define MD_FEATURE_PPL 1024 /* support PPL */ 330 #define MD_FEATURE_ALL (MD_FEATURE_BITMAP_OFFSET \ 331 |MD_FEATURE_RECOVERY_OFFSET \ 332 |MD_FEATURE_RESHAPE_ACTIVE \ 333 |MD_FEATURE_BAD_BLOCKS \ 334 |MD_FEATURE_REPLACEMENT \ 335 |MD_FEATURE_RESHAPE_BACKWARDS \ 336 |MD_FEATURE_NEW_OFFSET \ 337 |MD_FEATURE_RECOVERY_BITMAP \ 338 |MD_FEATURE_CLUSTERED \ 339 |MD_FEATURE_JOURNAL \ 340 |MD_FEATURE_PPL \ 341 ) 342 343 struct r5l_payload_header { 344 __le16 type; 345 __le16 flags; 346 } __attribute__ ((__packed__)); 347 348 enum r5l_payload_type { 349 R5LOG_PAYLOAD_DATA = 0, 350 R5LOG_PAYLOAD_PARITY = 1, 351 R5LOG_PAYLOAD_FLUSH = 2, 352 }; 353 354 struct r5l_payload_data_parity { 355 struct r5l_payload_header header; 356 __le32 size; /* sector. data/parity size. each 4k 357 * has a checksum */ 358 __le64 location; /* sector. For data, it's raid sector. For 359 * parity, it's stripe sector */ 360 __le32 checksum[]; 361 } __attribute__ ((__packed__)); 362 363 enum r5l_payload_data_parity_flag { 364 R5LOG_PAYLOAD_FLAG_DISCARD = 1, /* payload is discard */ 365 /* 366 * RESHAPED/RESHAPING is only set when there is reshape activity. Note, 367 * both data/parity of a stripe should have the same flag set 368 * 369 * RESHAPED: reshape is running, and this stripe finished reshape 370 * RESHAPING: reshape is running, and this stripe isn't reshaped 371 */ 372 R5LOG_PAYLOAD_FLAG_RESHAPED = 2, 373 R5LOG_PAYLOAD_FLAG_RESHAPING = 3, 374 }; 375 376 struct r5l_payload_flush { 377 struct r5l_payload_header header; 378 __le32 size; /* flush_stripes size, bytes */ 379 __le64 flush_stripes[]; 380 } __attribute__ ((__packed__)); 381 382 enum r5l_payload_flush_flag { 383 R5LOG_PAYLOAD_FLAG_FLUSH_STRIPE = 1, /* data represents whole stripe */ 384 }; 385 386 struct r5l_meta_block { 387 __le32 magic; 388 __le32 checksum; 389 __u8 version; 390 __u8 __zero_pading_1; 391 __le16 __zero_pading_2; 392 __le32 meta_size; /* whole size of the block */ 393 394 __le64 seq; 395 __le64 position; /* sector, start from rdev->data_offset, current position */ 396 struct r5l_payload_header payloads[]; 397 } __attribute__ ((__packed__)); 398 399 #define R5LOG_VERSION 0x1 400 #define R5LOG_MAGIC 0x6433c509 401 402 struct ppl_header_entry { 403 __le64 data_sector; /* raid sector of the new data */ 404 __le32 pp_size; /* length of partial parity */ 405 __le32 data_size; /* length of data */ 406 __le32 parity_disk; /* member disk containing parity */ 407 __le32 checksum; /* checksum of partial parity data for this 408 * entry (~crc32c) */ 409 } __attribute__ ((__packed__)); 410 411 #define PPL_HEADER_SIZE 4096 412 #define PPL_HDR_RESERVED 512 413 #define PPL_HDR_ENTRY_SPACE \ 414 (PPL_HEADER_SIZE - PPL_HDR_RESERVED - 4 * sizeof(__le32) - sizeof(__le64)) 415 #define PPL_HDR_MAX_ENTRIES \ 416 (PPL_HDR_ENTRY_SPACE / sizeof(struct ppl_header_entry)) 417 418 struct ppl_header { 419 __u8 reserved[PPL_HDR_RESERVED];/* reserved space, fill with 0xff */ 420 __le32 signature; /* signature (family number of volume) */ 421 __le32 padding; /* zero pad */ 422 __le64 generation; /* generation number of the header */ 423 __le32 entries_count; /* number of entries in entry array */ 424 __le32 checksum; /* checksum of the header (~crc32c) */ 425 struct ppl_header_entry entries[PPL_HDR_MAX_ENTRIES]; 426 } __attribute__ ((__packed__)); 427 428 #endif 429