include/uapi/linux/raid/md_p.h

   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
  99 typedef 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
 130 typedef 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
 210 static 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  */
 224 struct 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
 328 struct r5l_payload_header {
 329         __le16 type;
 330         __le16 flags;
 331 } __attribute__ ((__packed__));
 332
 333 enum r5l_payload_type {
 334         R5LOG_PAYLOAD_DATA = 0,
 335         R5LOG_PAYLOAD_PARITY = 1,
 336         R5LOG_PAYLOAD_FLUSH = 2,
 337 };
 338
 339 struct 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
 348 enum 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
 361 struct r5l_payload_flush {
 362         struct r5l_payload_header header;
 363         __le32 size; /* flush_stripes size, bytes */
 364         __le64 flush_stripes[];
 365 } __attribute__ ((__packed__));
 366
 367 enum r5l_payload_flush_flag {
 368         R5LOG_PAYLOAD_FLAG_FLUSH_STRIPE = 1, /* data represents whole stripe */
 369 };
 370
 371 struct 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