1 /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ 2 /* 3 md_p.h : physical layout of Linux RAID devices 4 Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 You should have received a copy of the GNU General Public License 12 (for example /usr/src/linux/COPYING); if not, write to the Free 13 Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 14 */ 15 16 #ifndef _MD_P_H 17 #define _MD_P_H 18 19 #include <linux/types.h> 20 #include <asm/byteorder.h> 21 22 /* 23 * RAID superblock. 24 * 25 * The RAID superblock maintains some statistics on each RAID configuration. 26 * Each real device in the RAID set contains it near the end of the device. 27 * Some of the ideas are copied from the ext2fs implementation. 28 * 29 * We currently use 4096 bytes as follows: 30 * 31 * word offset function 32 * 33 * 0 - 31 Constant generic RAID device information. 34 * 32 - 63 Generic state information. 35 * 64 - 127 Personality specific information. 36 * 128 - 511 12 32-words descriptors of the disks in the raid set. 37 * 512 - 911 Reserved. 38 * 912 - 1023 Disk specific descriptor. 39 */ 40 41 /* 42 * If x is the real device size in bytes, we return an apparent size of: 43 * 44 * y = (x & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES 45 * 46 * and place the 4kB superblock at offset y. 47 */ 48 #define MD_RESERVED_BYTES (64 * 1024) 49 #define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512) 50 51 #define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS) 52 53 #define MD_SB_BYTES 4096 54 #define MD_SB_WORDS (MD_SB_BYTES / 4) 55 #define MD_SB_SECTORS (MD_SB_BYTES / 512) 56 57 /* 58 * The following are counted in 32-bit words 59 */ 60 #define MD_SB_GENERIC_OFFSET 0 61 #define MD_SB_PERSONALITY_OFFSET 64 62 #define MD_SB_DISKS_OFFSET 128 63 #define MD_SB_DESCRIPTOR_OFFSET 992 64 65 #define MD_SB_GENERIC_CONSTANT_WORDS 32 66 #define MD_SB_GENERIC_STATE_WORDS 32 67 #define MD_SB_GENERIC_WORDS (MD_SB_GENERIC_CONSTANT_WORDS + MD_SB_GENERIC_STATE_WORDS) 68 #define MD_SB_PERSONALITY_WORDS 64 69 #define MD_SB_DESCRIPTOR_WORDS 32 70 #define MD_SB_DISKS 27 71 #define MD_SB_DISKS_WORDS (MD_SB_DISKS*MD_SB_DESCRIPTOR_WORDS) 72 #define MD_SB_RESERVED_WORDS (1024 - MD_SB_GENERIC_WORDS - MD_SB_PERSONALITY_WORDS - MD_SB_DISKS_WORDS - MD_SB_DESCRIPTOR_WORDS) 73 #define MD_SB_EQUAL_WORDS (MD_SB_GENERIC_WORDS + MD_SB_PERSONALITY_WORDS + MD_SB_DISKS_WORDS) 74 75 /* 76 * Device "operational" state bits 77 */ 78 #define MD_DISK_FAULTY 0 /* disk is faulty / operational */ 79 #define MD_DISK_ACTIVE 1 /* disk is running or spare disk */ 80 #define MD_DISK_SYNC 2 /* disk is in sync with the raid set */ 81 #define MD_DISK_REMOVED 3 /* disk is in sync with the raid set */ 82 #define MD_DISK_CLUSTER_ADD 4 /* Initiate a disk add across the cluster 83 * For clustered enviroments only. 84 */ 85 #define MD_DISK_CANDIDATE 5 /* disk is added as spare (local) until confirmed 86 * For clustered enviroments only. 87 */ 88 #define MD_DISK_FAILFAST 10 /* Send REQ_FAILFAST if there are multiple 89 * devices available - and don't try to 90 * correct read errors. 91 */ 92 93 #define MD_DISK_WRITEMOSTLY 9 /* disk is "write-mostly" is RAID1 config. 94 * read requests will only be sent here in 95 * dire need 96 */ 97 #define MD_DISK_JOURNAL 18 /* disk is used as the write journal in RAID-5/6 */ 98 99 #define MD_DISK_ROLE_SPARE 0xffff 100 #define MD_DISK_ROLE_FAULTY 0xfffe 101 #define MD_DISK_ROLE_JOURNAL 0xfffd 102 #define MD_DISK_ROLE_MAX 0xff00 /* max value of regular disk role */ 103 104 typedef struct mdp_device_descriptor_s { 105 __u32 number; /* 0 Device number in the entire set */ 106 __u32 major; /* 1 Device major number */ 107 __u32 minor; /* 2 Device minor number */ 108 __u32 raid_disk; /* 3 The role of the device in the raid set */ 109 __u32 state; /* 4 Operational state */ 110 __u32 reserved[MD_SB_DESCRIPTOR_WORDS - 5]; 111 } mdp_disk_t; 112 113 #define MD_SB_MAGIC 0xa92b4efc 114 115 /* 116 * Superblock state bits 117 */ 118 #define MD_SB_CLEAN 0 119 #define MD_SB_ERRORS 1 120 121 #define MD_SB_CLUSTERED 5 /* MD is clustered */ 122 #define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */ 123 124 /* 125 * Notes: 126 * - if an array is being reshaped (restriped) in order to change the 127 * the number of active devices in the array, 'raid_disks' will be 128 * the larger of the old and new numbers. 'delta_disks' will 129 * be the "new - old". So if +ve, raid_disks is the new value, and 130 * "raid_disks-delta_disks" is the old. If -ve, raid_disks is the 131 * old value and "raid_disks+delta_disks" is the new (smaller) value. 132 */ 133 134 135 typedef struct mdp_superblock_s { 136 /* 137 * Constant generic information 138 */ 139 __u32 md_magic; /* 0 MD identifier */ 140 __u32 major_version; /* 1 major version to which the set conforms */ 141 __u32 minor_version; /* 2 minor version ... */ 142 __u32 patch_version; /* 3 patchlevel version ... */ 143 __u32 gvalid_words; /* 4 Number of used words in this section */ 144 __u32 set_uuid0; /* 5 Raid set identifier */ 145 __u32 ctime; /* 6 Creation time */ 146 __u32 level; /* 7 Raid personality */ 147 __u32 size; /* 8 Apparent size of each individual disk */ 148 __u32 nr_disks; /* 9 total disks in the raid set */ 149 __u32 raid_disks; /* 10 disks in a fully functional raid set */ 150 __u32 md_minor; /* 11 preferred MD minor device number */ 151 __u32 not_persistent; /* 12 does it have a persistent superblock */ 152 __u32 set_uuid1; /* 13 Raid set identifier #2 */ 153 __u32 set_uuid2; /* 14 Raid set identifier #3 */ 154 __u32 set_uuid3; /* 15 Raid set identifier #4 */ 155 __u32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 16]; 156 157 /* 158 * Generic state information 159 */ 160 __u32 utime; /* 0 Superblock update time */ 161 __u32 state; /* 1 State bits (clean, ...) */ 162 __u32 active_disks; /* 2 Number of currently active disks */ 163 __u32 working_disks; /* 3 Number of working disks */ 164 __u32 failed_disks; /* 4 Number of failed disks */ 165 __u32 spare_disks; /* 5 Number of spare disks */ 166 __u32 sb_csum; /* 6 checksum of the whole superblock */ 167 #if defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN) 168 __u32 events_hi; /* 7 high-order of superblock update count */ 169 __u32 events_lo; /* 8 low-order of superblock update count */ 170 __u32 cp_events_hi; /* 9 high-order of checkpoint update count */ 171 __u32 cp_events_lo; /* 10 low-order of checkpoint update count */ 172 #elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN) 173 __u32 events_lo; /* 7 low-order of superblock update count */ 174 __u32 events_hi; /* 8 high-order of superblock update count */ 175 __u32 cp_events_lo; /* 9 low-order of checkpoint update count */ 176 __u32 cp_events_hi; /* 10 high-order of checkpoint update count */ 177 #else 178 #error unspecified endianness 179 #endif 180 __u32 recovery_cp; /* 11 recovery checkpoint sector count */ 181 /* There are only valid for minor_version > 90 */ 182 __u64 reshape_position; /* 12,13 next address in array-space for reshape */ 183 __u32 new_level; /* 14 new level we are reshaping to */ 184 __u32 delta_disks; /* 15 change in number of raid_disks */ 185 __u32 new_layout; /* 16 new layout */ 186 __u32 new_chunk; /* 17 new chunk size (bytes) */ 187 __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 18]; 188 189 /* 190 * Personality information 191 */ 192 __u32 layout; /* 0 the array's physical layout */ 193 __u32 chunk_size; /* 1 chunk size in bytes */ 194 __u32 root_pv; /* 2 LV root PV */ 195 __u32 root_block; /* 3 LV root block */ 196 __u32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 4]; 197 198 /* 199 * Disks information 200 */ 201 mdp_disk_t disks[MD_SB_DISKS]; 202 203 /* 204 * Reserved 205 */ 206 __u32 reserved[MD_SB_RESERVED_WORDS]; 207 208 /* 209 * Active descriptor 210 */ 211 mdp_disk_t this_disk; 212 213 } mdp_super_t; 214 md_event(mdp_super_t * sb)215 static inline __u64 md_event(mdp_super_t *sb) { 216 __u64 ev = sb->events_hi; 217 return (ev<<32)| sb->events_lo; 218 } 219 220 #define MD_SUPERBLOCK_1_TIME_SEC_MASK ((1ULL<<40) - 1) 221 222 /* 223 * The version-1 superblock : 224 * All numeric fields are little-endian. 225 * 226 * total size: 256 bytes plus 2 per device. 227 * 1K allows 384 devices. 228 */ 229 struct mdp_superblock_1 { 230 /* constant array information - 128 bytes */ 231 __le32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */ 232 __le32 major_version; /* 1 */ 233 __le32 feature_map; /* bit 0 set if 'bitmap_offset' is meaningful */ 234 __le32 pad0; /* always set to 0 when writing */ 235 236 __u8 set_uuid[16]; /* user-space generated. */ 237 char set_name[32]; /* set and interpreted by user-space */ 238 239 __le64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/ 240 __le32 level; /* -4 (multipath), -1 (linear), 0,1,4,5 */ 241 __le32 layout; /* only for raid5 and raid10 currently */ 242 __le64 size; /* used size of component devices, in 512byte sectors */ 243 244 __le32 chunksize; /* in 512byte sectors */ 245 __le32 raid_disks; 246 union { 247 __le32 bitmap_offset; /* sectors after start of superblock that bitmap starts 248 * NOTE: signed, so bitmap can be before superblock 249 * only meaningful of feature_map[0] is set. 250 */ 251 252 /* only meaningful when feature_map[MD_FEATURE_PPL] is set */ 253 struct { 254 __le16 offset; /* sectors from start of superblock that ppl starts (signed) */ 255 __le16 size; /* ppl size in sectors */ 256 } ppl; 257 }; 258 259 /* These are only valid with feature bit '4' */ 260 __le32 new_level; /* new level we are reshaping to */ 261 __le64 reshape_position; /* next address in array-space for reshape */ 262 __le32 delta_disks; /* change in number of raid_disks */ 263 __le32 new_layout; /* new layout */ 264 __le32 new_chunk; /* new chunk size (512byte sectors) */ 265 __le32 new_offset; /* signed number to add to data_offset in new 266 * layout. 0 == no-change. This can be 267 * different on each device in the array. 268 */ 269 270 /* constant this-device information - 64 bytes */ 271 __le64 data_offset; /* sector start of data, often 0 */ 272 __le64 data_size; /* sectors in this device that can be used for data */ 273 __le64 super_offset; /* sector start of this superblock */ 274 union { 275 __le64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */ 276 __le64 journal_tail;/* journal tail of journal device (from data_offset) */ 277 }; 278 __le32 dev_number; /* permanent identifier of this device - not role in raid */ 279 __le32 cnt_corrected_read; /* number of read errors that were corrected by re-writing */ 280 __u8 device_uuid[16]; /* user-space setable, ignored by kernel */ 281 __u8 devflags; /* per-device flags. Only two defined...*/ 282 #define WriteMostly1 1 /* mask for writemostly flag in above */ 283 #define FailFast1 2 /* Should avoid retries and fixups and just fail */ 284 /* Bad block log. If there are any bad blocks the feature flag is set. 285 * If offset and size are non-zero, that space is reserved and available 286 */ 287 __u8 bblog_shift; /* shift from sectors to block size */ 288 __le16 bblog_size; /* number of sectors reserved for list */ 289 __le32 bblog_offset; /* sector offset from superblock to bblog, 290 * signed - not unsigned */ 291 292 /* array state information - 64 bytes */ 293 __le64 utime; /* 40 bits second, 24 bits microseconds */ 294 __le64 events; /* incremented when superblock updated */ 295 __le64 resync_offset; /* data before this offset (from data_offset) known to be in sync */ 296 __le32 sb_csum; /* checksum up to devs[max_dev] */ 297 __le32 max_dev; /* size of devs[] array to consider */ 298 __u8 pad3[64-32]; /* set to 0 when writing */ 299 300 /* device state information. Indexed by dev_number. 301 * 2 bytes per device 302 * Note there are no per-device state flags. State information is rolled 303 * into the 'roles' value. If a device is spare or faulty, then it doesn't 304 * have a meaningful role. 305 */ 306 __le16 dev_roles[0]; /* role in array, or 0xffff for a spare, or 0xfffe for faulty */ 307 }; 308 309 /* feature_map bits */ 310 #define MD_FEATURE_BITMAP_OFFSET 1 311 #define MD_FEATURE_RECOVERY_OFFSET 2 /* recovery_offset is present and 312 * must be honoured 313 */ 314 #define MD_FEATURE_RESHAPE_ACTIVE 4 315 #define MD_FEATURE_BAD_BLOCKS 8 /* badblock list is not empty */ 316 #define MD_FEATURE_REPLACEMENT 16 /* This device is replacing an 317 * active device with same 'role'. 318 * 'recovery_offset' is also set. 319 */ 320 #define MD_FEATURE_RESHAPE_BACKWARDS 32 /* Reshape doesn't change number 321 * of devices, but is going 322 * backwards anyway. 323 */ 324 #define MD_FEATURE_NEW_OFFSET 64 /* new_offset must be honoured */ 325 #define MD_FEATURE_RECOVERY_BITMAP 128 /* recovery that is happening 326 * is guided by bitmap. 327 */ 328 #define MD_FEATURE_CLUSTERED 256 /* clustered MD */ 329 #define MD_FEATURE_JOURNAL 512 /* support write cache */ 330 #define MD_FEATURE_PPL 1024 /* support PPL */ 331 #define MD_FEATURE_MULTIPLE_PPLS 2048 /* support for multiple PPLs */ 332 #define MD_FEATURE_RAID0_LAYOUT 4096 /* layout is meaningful for RAID0 */ 333 #define MD_FEATURE_ALL (MD_FEATURE_BITMAP_OFFSET \ 334 |MD_FEATURE_RECOVERY_OFFSET \ 335 |MD_FEATURE_RESHAPE_ACTIVE \ 336 |MD_FEATURE_BAD_BLOCKS \ 337 |MD_FEATURE_REPLACEMENT \ 338 |MD_FEATURE_RESHAPE_BACKWARDS \ 339 |MD_FEATURE_NEW_OFFSET \ 340 |MD_FEATURE_RECOVERY_BITMAP \ 341 |MD_FEATURE_CLUSTERED \ 342 |MD_FEATURE_JOURNAL \ 343 |MD_FEATURE_PPL \ 344 |MD_FEATURE_MULTIPLE_PPLS \ 345 |MD_FEATURE_RAID0_LAYOUT \ 346 ) 347 348 struct r5l_payload_header { 349 __le16 type; 350 __le16 flags; 351 } __attribute__ ((__packed__)); 352 353 enum r5l_payload_type { 354 R5LOG_PAYLOAD_DATA = 0, 355 R5LOG_PAYLOAD_PARITY = 1, 356 R5LOG_PAYLOAD_FLUSH = 2, 357 }; 358 359 struct r5l_payload_data_parity { 360 struct r5l_payload_header header; 361 __le32 size; /* sector. data/parity size. each 4k 362 * has a checksum */ 363 __le64 location; /* sector. For data, it's raid sector. For 364 * parity, it's stripe sector */ 365 __le32 checksum[]; 366 } __attribute__ ((__packed__)); 367 368 enum r5l_payload_data_parity_flag { 369 R5LOG_PAYLOAD_FLAG_DISCARD = 1, /* payload is discard */ 370 /* 371 * RESHAPED/RESHAPING is only set when there is reshape activity. Note, 372 * both data/parity of a stripe should have the same flag set 373 * 374 * RESHAPED: reshape is running, and this stripe finished reshape 375 * RESHAPING: reshape is running, and this stripe isn't reshaped 376 */ 377 R5LOG_PAYLOAD_FLAG_RESHAPED = 2, 378 R5LOG_PAYLOAD_FLAG_RESHAPING = 3, 379 }; 380 381 struct r5l_payload_flush { 382 struct r5l_payload_header header; 383 __le32 size; /* flush_stripes size, bytes */ 384 __le64 flush_stripes[]; 385 } __attribute__ ((__packed__)); 386 387 enum r5l_payload_flush_flag { 388 R5LOG_PAYLOAD_FLAG_FLUSH_STRIPE = 1, /* data represents whole stripe */ 389 }; 390 391 struct r5l_meta_block { 392 __le32 magic; 393 __le32 checksum; 394 __u8 version; 395 __u8 __zero_pading_1; 396 __le16 __zero_pading_2; 397 __le32 meta_size; /* whole size of the block */ 398 399 __le64 seq; 400 __le64 position; /* sector, start from rdev->data_offset, current position */ 401 struct r5l_payload_header payloads[]; 402 } __attribute__ ((__packed__)); 403 404 #define R5LOG_VERSION 0x1 405 #define R5LOG_MAGIC 0x6433c509 406 407 struct ppl_header_entry { 408 __le64 data_sector; /* raid sector of the new data */ 409 __le32 pp_size; /* length of partial parity */ 410 __le32 data_size; /* length of data */ 411 __le32 parity_disk; /* member disk containing parity */ 412 __le32 checksum; /* checksum of partial parity data for this 413 * entry (~crc32c) */ 414 } __attribute__ ((__packed__)); 415 416 #define PPL_HEADER_SIZE 4096 417 #define PPL_HDR_RESERVED 512 418 #define PPL_HDR_ENTRY_SPACE \ 419 (PPL_HEADER_SIZE - PPL_HDR_RESERVED - 4 * sizeof(__le32) - sizeof(__le64)) 420 #define PPL_HDR_MAX_ENTRIES \ 421 (PPL_HDR_ENTRY_SPACE / sizeof(struct ppl_header_entry)) 422 423 struct ppl_header { 424 __u8 reserved[PPL_HDR_RESERVED];/* reserved space, fill with 0xff */ 425 __le32 signature; /* signature (family number of volume) */ 426 __le32 padding; /* zero pad */ 427 __le64 generation; /* generation number of the header */ 428 __le32 entries_count; /* number of entries in entry array */ 429 __le32 checksum; /* checksum of the header (~crc32c) */ 430 struct ppl_header_entry entries[PPL_HDR_MAX_ENTRIES]; 431 } __attribute__ ((__packed__)); 432 433 #endif 434