drivers/md/dm-raid.c

   1 /*
   2  * Copyright (C) 2010-2011 Neil Brown
   3  * Copyright (C) 2010-2011 Red Hat, Inc. All rights reserved.
   4  *
   5  * This file is released under the GPL.
   6  */
   7
   8 #include <linux/slab.h>
   9 #include <linux/module.h>
  10
  11 #include "md.h"
  12 #include "raid1.h"
  13 #include "raid5.h"
  14 #include "bitmap.h"
  15
  16 #include <linux/device-mapper.h>
  17
  18 #define DM_MSG_PREFIX "raid"
  19
  20 /*
  21  * The following flags are used by dm-raid.c to set up the array state.
  22  * They must be cleared before md_run is called.
  23  */
  24 #define FirstUse 10             /* rdev flag */
  25
  26 struct raid_dev {
  27         /*
  28          * Two DM devices, one to hold metadata and one to hold the
  29          * actual data/parity.  The reason for this is to not confuse
  30          * ti->len and give more flexibility in altering size and
  31          * characteristics.
  32          *
  33          * While it is possible for this device to be associated
  34          * with a different physical device than the data_dev, it
  35          * is intended for it to be the same.
  36          *    |--------- Physical Device ---------|
  37          *    |- meta_dev -|------ data_dev ------|
  38          */
  39         struct dm_dev *meta_dev;
  40         struct dm_dev *data_dev;
  41         struct md_rdev rdev;
  42 };
  43
  44 /*
  45  * Flags for rs->print_flags field.
  46  */
  47 #define DMPF_SYNC              0x1
  48 #define DMPF_NOSYNC            0x2
  49 #define DMPF_REBUILD           0x4
  50 #define DMPF_DAEMON_SLEEP      0x8
  51 #define DMPF_MIN_RECOVERY_RATE 0x10
  52 #define DMPF_MAX_RECOVERY_RATE 0x20
  53 #define DMPF_MAX_WRITE_BEHIND  0x40
  54 #define DMPF_STRIPE_CACHE      0x80
  55 #define DMPF_REGION_SIZE       0X100
  56 struct raid_set {
  57         struct dm_target *ti;
  58
  59         uint32_t bitmap_loaded;
  60         uint32_t print_flags;
  61
  62         struct mddev md;
  63         struct raid_type *raid_type;
  64         struct dm_target_callbacks callbacks;
  65
  66         struct raid_dev dev[0];
  67 };
  68
  69 /* Supported raid types and properties. */
  70 static struct raid_type {
  71         const char *name;               /* RAID algorithm. */
  72         const char *descr;              /* Descriptor text for logging. */
  73         const unsigned parity_devs;     /* # of parity devices. */
  74         const unsigned minimal_devs;    /* minimal # of devices in set. */
  75         const unsigned level;           /* RAID level. */
  76         const unsigned algorithm;       /* RAID algorithm. */
  77 } raid_types[] = {
  78         {"raid1",    "RAID1 (mirroring)",               0, 2, 1, 0 /* NONE */},
  79         {"raid4",    "RAID4 (dedicated parity disk)",   1, 2, 5, ALGORITHM_PARITY_0},
  80         {"raid5_la", "RAID5 (left asymmetric)",         1, 2, 5, ALGORITHM_LEFT_ASYMMETRIC},
  81         {"raid5_ra", "RAID5 (right asymmetric)",        1, 2, 5, ALGORITHM_RIGHT_ASYMMETRIC},
  82         {"raid5_ls", "RAID5 (left symmetric)",          1, 2, 5, ALGORITHM_LEFT_SYMMETRIC},
  83         {"raid5_rs", "RAID5 (right symmetric)",         1, 2, 5, ALGORITHM_RIGHT_SYMMETRIC},
  84         {"raid6_zr", "RAID6 (zero restart)",            2, 4, 6, ALGORITHM_ROTATING_ZERO_RESTART},
  85         {"raid6_nr", "RAID6 (N restart)",               2, 4, 6, ALGORITHM_ROTATING_N_RESTART},
  86         {"raid6_nc", "RAID6 (N continue)",              2, 4, 6, ALGORITHM_ROTATING_N_CONTINUE}
  87 };
  88
  89 static struct raid_type *get_raid_type(char *name)
  90 {
  91         int i;
  92
  93         for (i = 0; i < ARRAY_SIZE(raid_types); i++)
  94                 if (!strcmp(raid_types[i].name, name))
  95                         return &raid_types[i];
  96
  97         return NULL;
  98 }
  99
 100 static struct raid_set *context_alloc(struct dm_target *ti, struct raid_type *raid_type, unsigned raid_devs)
 101 {
 102         unsigned i;
 103         struct raid_set *rs;
 104
 105         if (raid_devs <= raid_type->parity_devs) {
 106                 ti->error = "Insufficient number of devices";
 107                 return ERR_PTR(-EINVAL);
 108         }
 109
 110         rs = kzalloc(sizeof(*rs) + raid_devs * sizeof(rs->dev[0]), GFP_KERNEL);
 111         if (!rs) {
 112                 ti->error = "Cannot allocate raid context";
 113                 return ERR_PTR(-ENOMEM);
 114         }
 115
 116         mddev_init(&rs->md);
 117
 118         rs->ti = ti;
 119         rs->raid_type = raid_type;
 120         rs->md.raid_disks = raid_devs;
 121         rs->md.level = raid_type->level;
 122         rs->md.new_level = rs->md.level;
 123         rs->md.layout = raid_type->algorithm;
 124         rs->md.new_layout = rs->md.layout;
 125         rs->md.delta_disks = 0;
 126         rs->md.recovery_cp = 0;
 127
 128         for (i = 0; i < raid_devs; i++)
 129                 md_rdev_init(&rs->dev[i].rdev);
 130
 131         /*
 132          * Remaining items to be initialized by further RAID params:
 133          *  rs->md.persistent
 134          *  rs->md.external
 135          *  rs->md.chunk_sectors
 136          *  rs->md.new_chunk_sectors
 137          *  rs->md.dev_sectors
 138          */
 139
 140         return rs;
 141 }
 142
 143 static void context_free(struct raid_set *rs)
 144 {
 145         int i;
 146
 147         for (i = 0; i < rs->md.raid_disks; i++) {
 148                 if (rs->dev[i].meta_dev)
 149                         dm_put_device(rs->ti, rs->dev[i].meta_dev);
 150                 md_rdev_clear(&rs->dev[i].rdev);
 151                 if (rs->dev[i].data_dev)
 152                         dm_put_device(rs->ti, rs->dev[i].data_dev);
 153         }
 154
 155         kfree(rs);
 156 }
 157
 158 /*
 159  * For every device we have two words
 160  *  <meta_dev>: meta device name or '-' if missing
 161  *  <data_dev>: data device name or '-' if missing
 162  *
 163  * The following are permitted:
 164  *    - -
 165  *    - <data_dev>
 166  *    <meta_dev> <data_dev>
 167  *
 168  * The following is not allowed:
 169  *    <meta_dev> -
 170  *
 171  * This code parses those words.  If there is a failure,
 172  * the caller must use context_free to unwind the operations.
 173  */
 174 static int dev_parms(struct raid_set *rs, char **argv)
 175 {
 176         int i;
 177         int rebuild = 0;
 178         int metadata_available = 0;
 179         int ret = 0;
 180
 181         for (i = 0; i < rs->md.raid_disks; i++, argv += 2) {
 182                 rs->dev[i].rdev.raid_disk = i;
 183
 184                 rs->dev[i].meta_dev = NULL;
 185                 rs->dev[i].data_dev = NULL;
 186
 187                 /*
 188                  * There are no offsets, since there is a separate device
 189                  * for data and metadata.
 190                  */
 191                 rs->dev[i].rdev.data_offset = 0;
 192                 rs->dev[i].rdev.mddev = &rs->md;
 193
 194                 if (strcmp(argv[0], "-")) {
 195                         ret = dm_get_device(rs->ti, argv[0],
 196                                             dm_table_get_mode(rs->ti->table),
 197                                             &rs->dev[i].meta_dev);
 198                         rs->ti->error = "RAID metadata device lookup failure";
 199                         if (ret)
 200                                 return ret;
 201
 202                         rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
 203                         if (!rs->dev[i].rdev.sb_page)
 204                                 return -ENOMEM;
 205                 }
 206
 207                 if (!strcmp(argv[1], "-")) {
 208                         if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
 209                             (!rs->dev[i].rdev.recovery_offset)) {
 210                                 rs->ti->error = "Drive designated for rebuild not specified";
 211                                 return -EINVAL;
 212                         }
 213
 214                         rs->ti->error = "No data device supplied with metadata device";
 215                         if (rs->dev[i].meta_dev)
 216                                 return -EINVAL;
 217
 218                         continue;
 219                 }
 220
 221                 ret = dm_get_device(rs->ti, argv[1],
 222                                     dm_table_get_mode(rs->ti->table),
 223                                     &rs->dev[i].data_dev);
 224                 if (ret) {
 225                         rs->ti->error = "RAID device lookup failure";
 226                         return ret;
 227                 }
 228
 229                 if (rs->dev[i].meta_dev) {
 230                         metadata_available = 1;
 231                         rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
 232                 }
 233                 rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
 234                 list_add(&rs->dev[i].rdev.same_set, &rs->md.disks);
 235                 if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
 236                         rebuild++;
 237         }
 238
 239         if (metadata_available) {
 240                 rs->md.external = 0;
 241                 rs->md.persistent = 1;
 242                 rs->md.major_version = 2;
 243         } else if (rebuild && !rs->md.recovery_cp) {
 244                 /*
 245                  * Without metadata, we will not be able to tell if the array
 246                  * is in-sync or not - we must assume it is not.  Therefore,
 247                  * it is impossible to rebuild a drive.
 248                  *
 249                  * Even if there is metadata, the on-disk information may
 250                  * indicate that the array is not in-sync and it will then
 251                  * fail at that time.
 252                  *
 253                  * User could specify 'nosync' option if desperate.
 254                  */
 255                 DMERR("Unable to rebuild drive while array is not in-sync");
 256                 rs->ti->error = "RAID device lookup failure";
 257                 return -EINVAL;
 258         }
 259
 260         return 0;
 261 }
 262
 263 /*
 264  * validate_region_size
 265  * @rs
 266  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
 267  *
 268  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
 269  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
 270  *
 271  * Returns: 0 on success, -EINVAL on failure.
 272  */
 273 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
 274 {
 275         unsigned long min_region_size = rs->ti->len / (1 << 21);
 276
 277         if (!region_size) {
 278                 /*
 279                  * Choose a reasonable default.  All figures in sectors.
 280                  */
 281                 if (min_region_size > (1 << 13)) {
 282                         DMINFO("Choosing default region size of %lu sectors",
 283                                region_size);
 284                         region_size = min_region_size;
 285                 } else {
 286                         DMINFO("Choosing default region size of 4MiB");
 287                         region_size = 1 << 13; /* sectors */
 288                 }
 289         } else {
 290                 /*
 291                  * Validate user-supplied value.
 292                  */
 293                 if (region_size > rs->ti->len) {
 294                         rs->ti->error = "Supplied region size is too large";
 295                         return -EINVAL;
 296                 }
 297
 298                 if (region_size < min_region_size) {
 299                         DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
 300                               region_size, min_region_size);
 301                         rs->ti->error = "Supplied region size is too small";
 302                         return -EINVAL;
 303                 }
 304
 305                 if (!is_power_of_2(region_size)) {
 306                         rs->ti->error = "Region size is not a power of 2";
 307                         return -EINVAL;
 308                 }
 309
 310                 if (region_size < rs->md.chunk_sectors) {
 311                         rs->ti->error = "Region size is smaller than the chunk size";
 312                         return -EINVAL;
 313                 }
 314         }
 315
 316         /*
 317          * Convert sectors to bytes.
 318          */
 319         rs->md.bitmap_info.chunksize = (region_size << 9);
 320
 321         return 0;
 322 }
 323
 324 /*
 325  * Possible arguments are...
 326  *      <chunk_size> [optional_args]
 327  *
 328  * Argument definitions
 329  *    <chunk_size>                      The number of sectors per disk that
 330  *                                      will form the "stripe"
 331  *    [[no]sync]                        Force or prevent recovery of the
 332  *                                      entire array
 333  *    [rebuild <idx>]                   Rebuild the drive indicated by the index
 334  *    [daemon_sleep <ms>]               Time between bitmap daemon work to
 335  *                                      clear bits
 336  *    [min_recovery_rate <kB/sec/disk>] Throttle RAID initialization
 337  *    [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization
 338  *    [write_mostly <idx>]              Indicate a write mostly drive via index
 339  *    [max_write_behind <sectors>]      See '-write-behind=' (man mdadm)
 340  *    [stripe_cache <sectors>]          Stripe cache size for higher RAIDs
 341  *    [region_size <sectors>]           Defines granularity of bitmap
 342  */
 343 static int parse_raid_params(struct raid_set *rs, char **argv,
 344                              unsigned num_raid_params)
 345 {
 346         unsigned i, rebuild_cnt = 0;
 347         unsigned long value, region_size = 0;
 348         sector_t sectors_per_dev = rs->ti->len;
 349         sector_t max_io_len;
 350         char *key;
 351
 352         /*
 353          * First, parse the in-order required arguments
 354          * "chunk_size" is the only argument of this type.
 355          */
 356         if ((strict_strtoul(argv[0], 10, &value) < 0)) {
 357                 rs->ti->error = "Bad chunk size";
 358                 return -EINVAL;
 359         } else if (rs->raid_type->level == 1) {
 360                 if (value)
 361                         DMERR("Ignoring chunk size parameter for RAID 1");
 362                 value = 0;
 363         } else if (!is_power_of_2(value)) {
 364                 rs->ti->error = "Chunk size must be a power of 2";
 365                 return -EINVAL;
 366         } else if (value < 8) {
 367                 rs->ti->error = "Chunk size value is too small";
 368                 return -EINVAL;
 369         }
 370
 371         rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
 372         argv++;
 373         num_raid_params--;
 374
 375         /*
 376          * We set each individual device as In_sync with a completed
 377          * 'recovery_offset'.  If there has been a device failure or
 378          * replacement then one of the following cases applies:
 379          *
 380          *   1) User specifies 'rebuild'.
 381          *      - Device is reset when param is read.
 382          *   2) A new device is supplied.
 383          *      - No matching superblock found, resets device.
 384          *   3) Device failure was transient and returns on reload.
 385          *      - Failure noticed, resets device for bitmap replay.
 386          *   4) Device hadn't completed recovery after previous failure.
 387          *      - Superblock is read and overrides recovery_offset.
 388          *
 389          * What is found in the superblocks of the devices is always
 390          * authoritative, unless 'rebuild' or '[no]sync' was specified.
 391          */
 392         for (i = 0; i < rs->md.raid_disks; i++) {
 393                 set_bit(In_sync, &rs->dev[i].rdev.flags);
 394                 rs->dev[i].rdev.recovery_offset = MaxSector;
 395         }
 396
 397         /*
 398          * Second, parse the unordered optional arguments
 399          */
 400         for (i = 0; i < num_raid_params; i++) {
 401                 if (!strcasecmp(argv[i], "nosync")) {
 402                         rs->md.recovery_cp = MaxSector;
 403                         rs->print_flags |= DMPF_NOSYNC;
 404                         continue;
 405                 }
 406                 if (!strcasecmp(argv[i], "sync")) {
 407                         rs->md.recovery_cp = 0;
 408                         rs->print_flags |= DMPF_SYNC;
 409                         continue;
 410                 }
 411
 412                 /* The rest of the optional arguments come in key/value pairs */
 413                 if ((i + 1) >= num_raid_params) {
 414                         rs->ti->error = "Wrong number of raid parameters given";
 415                         return -EINVAL;
 416                 }
 417
 418                 key = argv[i++];
 419                 if (strict_strtoul(argv[i], 10, &value) < 0) {
 420                         rs->ti->error = "Bad numerical argument given in raid params";
 421                         return -EINVAL;
 422                 }
 423
 424                 if (!strcasecmp(key, "rebuild")) {
 425                         rebuild_cnt++;
 426
 427                         switch (rs->raid_type->level) {
 428                         case 1:
 429                                 if (rebuild_cnt >= rs->md.raid_disks) {
 430                                         rs->ti->error = "Too many rebuild devices specified";
 431                                         return -EINVAL;
 432                                 }
 433                                 break;
 434                         case 4:
 435                         case 5:
 436                         case 6:
 437                                 if (rebuild_cnt > rs->raid_type->parity_devs) {
 438                                         rs->ti->error = "Too many rebuild devices specified for given RAID type";
 439                                         return -EINVAL;
 440                                 }
 441                                 break;
 442                         default:
 443                                 DMERR("The rebuild parameter is not supported for %s", rs->raid_type->name);
 444                                 rs->ti->error = "Rebuild not supported for this RAID type";
 445                                 return -EINVAL;
 446                         }
 447
 448                         if (value > rs->md.raid_disks) {
 449                                 rs->ti->error = "Invalid rebuild index given";
 450                                 return -EINVAL;
 451                         }
 452                         clear_bit(In_sync, &rs->dev[value].rdev.flags);
 453                         rs->dev[value].rdev.recovery_offset = 0;
 454                         rs->print_flags |= DMPF_REBUILD;
 455                 } else if (!strcasecmp(key, "write_mostly")) {
 456                         if (rs->raid_type->level != 1) {
 457                                 rs->ti->error = "write_mostly option is only valid for RAID1";
 458                                 return -EINVAL;
 459                         }
 460                         if (value >= rs->md.raid_disks) {
 461                                 rs->ti->error = "Invalid write_mostly drive index given";
 462                                 return -EINVAL;
 463                         }
 464                         set_bit(WriteMostly, &rs->dev[value].rdev.flags);
 465                 } else if (!strcasecmp(key, "max_write_behind")) {
 466                         if (rs->raid_type->level != 1) {
 467                                 rs->ti->error = "max_write_behind option is only valid for RAID1";
 468                                 return -EINVAL;
 469                         }
 470                         rs->print_flags |= DMPF_MAX_WRITE_BEHIND;
 471
 472                         /*
 473                          * In device-mapper, we specify things in sectors, but
 474                          * MD records this value in kB
 475                          */
 476                         value /= 2;
 477                         if (value > COUNTER_MAX) {
 478                                 rs->ti->error = "Max write-behind limit out of range";
 479                                 return -EINVAL;
 480                         }
 481                         rs->md.bitmap_info.max_write_behind = value;
 482                 } else if (!strcasecmp(key, "daemon_sleep")) {
 483                         rs->print_flags |= DMPF_DAEMON_SLEEP;
 484                         if (!value || (value > MAX_SCHEDULE_TIMEOUT)) {
 485                                 rs->ti->error = "daemon sleep period out of range";
 486                                 return -EINVAL;
 487                         }
 488                         rs->md.bitmap_info.daemon_sleep = value;
 489                 } else if (!strcasecmp(key, "stripe_cache")) {
 490                         rs->print_flags |= DMPF_STRIPE_CACHE;
 491
 492                         /*
 493                          * In device-mapper, we specify things in sectors, but
 494                          * MD records this value in kB
 495                          */
 496                         value /= 2;
 497
 498                         if (rs->raid_type->level < 5) {
 499                                 rs->ti->error = "Inappropriate argument: stripe_cache";
 500                                 return -EINVAL;
 501                         }
 502                         if (raid5_set_cache_size(&rs->md, (int)value)) {
 503                                 rs->ti->error = "Bad stripe_cache size";
 504                                 return -EINVAL;
 505                         }
 506                 } else if (!strcasecmp(key, "min_recovery_rate")) {
 507                         rs->print_flags |= DMPF_MIN_RECOVERY_RATE;
 508                         if (value > INT_MAX) {
 509                                 rs->ti->error = "min_recovery_rate out of range";
 510                                 return -EINVAL;
 511                         }
 512                         rs->md.sync_speed_min = (int)value;
 513                 } else if (!strcasecmp(key, "max_recovery_rate")) {
 514                         rs->print_flags |= DMPF_MAX_RECOVERY_RATE;
 515                         if (value > INT_MAX) {
 516                                 rs->ti->error = "max_recovery_rate out of range";
 517                                 return -EINVAL;
 518                         }
 519                         rs->md.sync_speed_max = (int)value;
 520                 } else if (!strcasecmp(key, "region_size")) {
 521                         rs->print_flags |= DMPF_REGION_SIZE;
 522                         region_size = value;
 523                 } else {
 524                         DMERR("Unable to parse RAID parameter: %s", key);
 525                         rs->ti->error = "Unable to parse RAID parameters";
 526                         return -EINVAL;
 527                 }
 528         }
 529
 530         if (validate_region_size(rs, region_size))
 531                 return -EINVAL;
 532
 533         if (rs->md.chunk_sectors)
 534                 max_io_len = rs->md.chunk_sectors;
 535         else
 536                 max_io_len = region_size;
 537
 538         if (dm_set_target_max_io_len(rs->ti, max_io_len))
 539                 return -EINVAL;
 540
 541         if ((rs->raid_type->level > 1) &&
 542             sector_div(sectors_per_dev, (rs->md.raid_disks - rs->raid_type->parity_devs))) {
 543                 rs->ti->error = "Target length not divisible by number of data devices";
 544                 return -EINVAL;
 545         }
 546         rs->md.dev_sectors = sectors_per_dev;
 547
 548         /* Assume there are no metadata devices until the drives are parsed */
 549         rs->md.persistent = 0;
 550         rs->md.external = 1;
 551
 552         return 0;
 553 }
 554
 555 static void do_table_event(struct work_struct *ws)
 556 {
 557         struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
 558
 559         dm_table_event(rs->ti->table);
 560 }
 561
 562 static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
 563 {
 564         struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
 565
 566         if (rs->raid_type->level == 1)
 567                 return md_raid1_congested(&rs->md, bits);
 568
 569         return md_raid5_congested(&rs->md, bits);
 570 }
 571
 572 /*
 573  * This structure is never routinely used by userspace, unlike md superblocks.
 574  * Devices with this superblock should only ever be accessed via device-mapper.
 575  */
 576 #define DM_RAID_MAGIC 0x64526D44
 577 struct dm_raid_superblock {
 578         __le32 magic;           /* "DmRd" */
 579         __le32 features;        /* Used to indicate possible future changes */
 580
 581         __le32 num_devices;     /* Number of devices in this array. (Max 64) */
 582         __le32 array_position;  /* The position of this drive in the array */
 583
 584         __le64 events;          /* Incremented by md when superblock updated */
 585         __le64 failed_devices;  /* Bit field of devices to indicate failures */
 586
 587         /*
 588          * This offset tracks the progress of the repair or replacement of
 589          * an individual drive.
 590          */
 591         __le64 disk_recovery_offset;
 592
 593         /*
 594          * This offset tracks the progress of the initial array
 595          * synchronisation/parity calculation.
 596          */
 597         __le64 array_resync_offset;
 598
 599         /*
 600          * RAID characteristics
 601          */
 602         __le32 level;
 603         __le32 layout;
 604         __le32 stripe_sectors;
 605
 606         __u8 pad[452];          /* Round struct to 512 bytes. */
 607                                 /* Always set to 0 when writing. */
 608 } __packed;
 609
 610 static int read_disk_sb(struct md_rdev *rdev, int size)
 611 {
 612         BUG_ON(!rdev->sb_page);
 613
 614         if (rdev->sb_loaded)
 615                 return 0;
 616
 617         if (!sync_page_io(rdev, 0, size, rdev->sb_page, READ, 1)) {
 618                 DMERR("Failed to read superblock of device at position %d",
 619                       rdev->raid_disk);
 620                 md_error(rdev->mddev, rdev);
 621                 return -EINVAL;
 622         }
 623
 624         rdev->sb_loaded = 1;
 625
 626         return 0;
 627 }
 628
 629 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
 630 {
 631         int i;
 632         uint64_t failed_devices;
 633         struct dm_raid_superblock *sb;
 634         struct raid_set *rs = container_of(mddev, struct raid_set, md);
 635
 636         sb = page_address(rdev->sb_page);
 637         failed_devices = le64_to_cpu(sb->failed_devices);
 638
 639         for (i = 0; i < mddev->raid_disks; i++)
 640                 if (!rs->dev[i].data_dev ||
 641                     test_bit(Faulty, &(rs->dev[i].rdev.flags)))
 642                         failed_devices |= (1ULL << i);
 643
 644         memset(sb, 0, sizeof(*sb));
 645
 646         sb->magic = cpu_to_le32(DM_RAID_MAGIC);
 647         sb->features = cpu_to_le32(0);  /* No features yet */
 648
 649         sb->num_devices = cpu_to_le32(mddev->raid_disks);
 650         sb->array_position = cpu_to_le32(rdev->raid_disk);
 651
 652         sb->events = cpu_to_le64(mddev->events);
 653         sb->failed_devices = cpu_to_le64(failed_devices);
 654
 655         sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
 656         sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
 657
 658         sb->level = cpu_to_le32(mddev->level);
 659         sb->layout = cpu_to_le32(mddev->layout);
 660         sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
 661 }
 662
 663 /*
 664  * super_load
 665  *
 666  * This function creates a superblock if one is not found on the device
 667  * and will decide which superblock to use if there's a choice.
 668  *
 669  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
 670  */
 671 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
 672 {
 673         int ret;
 674         struct dm_raid_superblock *sb;
 675         struct dm_raid_superblock *refsb;
 676         uint64_t events_sb, events_refsb;
 677
 678         rdev->sb_start = 0;
 679         rdev->sb_size = sizeof(*sb);
 680
 681         ret = read_disk_sb(rdev, rdev->sb_size);
 682         if (ret)
 683                 return ret;
 684
 685         sb = page_address(rdev->sb_page);
 686
 687         /*
 688          * Two cases that we want to write new superblocks and rebuild:
 689          * 1) New device (no matching magic number)
 690          * 2) Device specified for rebuild (!In_sync w/ offset == 0)
 691          */
 692         if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
 693             (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
 694                 super_sync(rdev->mddev, rdev);
 695
 696                 set_bit(FirstUse, &rdev->flags);
 697
 698                 /* Force writing of superblocks to disk */
 699                 set_bit(MD_CHANGE_DEVS, &rdev->mddev->flags);
 700
 701                 /* Any superblock is better than none, choose that if given */
 702                 return refdev ? 0 : 1;
 703         }
 704
 705         if (!refdev)
 706                 return 1;
 707
 708         events_sb = le64_to_cpu(sb->events);
 709
 710         refsb = page_address(refdev->sb_page);
 711         events_refsb = le64_to_cpu(refsb->events);
 712
 713         return (events_sb > events_refsb) ? 1 : 0;
 714 }
 715
 716 static int super_init_validation(struct mddev *mddev, struct md_rdev *rdev)
 717 {
 718         int role;
 719         struct raid_set *rs = container_of(mddev, struct raid_set, md);
 720         uint64_t events_sb;
 721         uint64_t failed_devices;
 722         struct dm_raid_superblock *sb;
 723         uint32_t new_devs = 0;
 724         uint32_t rebuilds = 0;
 725         struct md_rdev *r;
 726         struct dm_raid_superblock *sb2;
 727
 728         sb = page_address(rdev->sb_page);
 729         events_sb = le64_to_cpu(sb->events);
 730         failed_devices = le64_to_cpu(sb->failed_devices);
 731
 732         /*
 733          * Initialise to 1 if this is a new superblock.
 734          */
 735         mddev->events = events_sb ? : 1;
 736
 737         /*
 738          * Reshaping is not currently allowed
 739          */
 740         if ((le32_to_cpu(sb->level) != mddev->level) ||
 741             (le32_to_cpu(sb->layout) != mddev->layout) ||
 742             (le32_to_cpu(sb->stripe_sectors) != mddev->chunk_sectors)) {
 743                 DMERR("Reshaping arrays not yet supported.");
 744                 return -EINVAL;
 745         }
 746
 747         /* We can only change the number of devices in RAID1 right now */
 748         if ((rs->raid_type->level != 1) &&
 749             (le32_to_cpu(sb->num_devices) != mddev->raid_disks)) {
 750                 DMERR("Reshaping arrays not yet supported.");
 751                 return -EINVAL;
 752         }
 753
 754         if (!(rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC)))
 755                 mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
 756
 757         /*
 758          * During load, we set FirstUse if a new superblock was written.
 759          * There are two reasons we might not have a superblock:
 760          * 1) The array is brand new - in which case, all of the
 761          *    devices must have their In_sync bit set.  Also,
 762          *    recovery_cp must be 0, unless forced.
 763          * 2) This is a new device being added to an old array
 764          *    and the new device needs to be rebuilt - in which
 765          *    case the In_sync bit will /not/ be set and
 766          *    recovery_cp must be MaxSector.
 767          */
 768         rdev_for_each(r, mddev) {
 769                 if (!test_bit(In_sync, &r->flags)) {
 770                         DMINFO("Device %d specified for rebuild: "
 771                                "Clearing superblock", r->raid_disk);
 772                         rebuilds++;
 773                 } else if (test_bit(FirstUse, &r->flags))
 774                         new_devs++;
 775         }
 776
 777         if (!rebuilds) {
 778                 if (new_devs == mddev->raid_disks) {
 779                         DMINFO("Superblocks created for new array");
 780                         set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
 781                 } else if (new_devs) {
 782                         DMERR("New device injected "
 783                               "into existing array without 'rebuild' "
 784                               "parameter specified");
 785                         return -EINVAL;
 786                 }
 787         } else if (new_devs) {
 788                 DMERR("'rebuild' devices cannot be "
 789                       "injected into an array with other first-time devices");
 790                 return -EINVAL;
 791         } else if (mddev->recovery_cp != MaxSector) {
 792                 DMERR("'rebuild' specified while array is not in-sync");
 793                 return -EINVAL;
 794         }
 795
 796         /*
 797          * Now we set the Faulty bit for those devices that are
 798          * recorded in the superblock as failed.
 799          */
 800         rdev_for_each(r, mddev) {
 801                 if (!r->sb_page)
 802                         continue;
 803                 sb2 = page_address(r->sb_page);
 804                 sb2->failed_devices = 0;
 805
 806                 /*
 807                  * Check for any device re-ordering.
 808                  */
 809                 if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
 810                         role = le32_to_cpu(sb2->array_position);
 811                         if (role != r->raid_disk) {
 812                                 if (rs->raid_type->level != 1) {
 813                                         rs->ti->error = "Cannot change device "
 814                                                 "positions in RAID array";
 815                                         return -EINVAL;
 816                                 }
 817                                 DMINFO("RAID1 device #%d now at position #%d",
 818                                        role, r->raid_disk);
 819                         }
 820
 821                         /*
 822                          * Partial recovery is performed on
 823                          * returning failed devices.
 824                          */
 825                         if (failed_devices & (1 << role))
 826                                 set_bit(Faulty, &r->flags);
 827                 }
 828         }
 829
 830         return 0;
 831 }
 832
 833 static int super_validate(struct mddev *mddev, struct md_rdev *rdev)
 834 {
 835         struct dm_raid_superblock *sb = page_address(rdev->sb_page);
 836
 837         /*
 838          * If mddev->events is not set, we know we have not yet initialized
 839          * the array.
 840          */
 841         if (!mddev->events && super_init_validation(mddev, rdev))
 842                 return -EINVAL;
 843
 844         mddev->bitmap_info.offset = 4096 >> 9; /* Enable bitmap creation */
 845         rdev->mddev->bitmap_info.default_offset = 4096 >> 9;
 846         if (!test_bit(FirstUse, &rdev->flags)) {
 847                 rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
 848                 if (rdev->recovery_offset != MaxSector)
 849                         clear_bit(In_sync, &rdev->flags);
 850         }
 851
 852         /*
 853          * If a device comes back, set it as not In_sync and no longer faulty.
 854          */
 855         if (test_bit(Faulty, &rdev->flags)) {
 856                 clear_bit(Faulty, &rdev->flags);
 857                 clear_bit(In_sync, &rdev->flags);
 858                 rdev->saved_raid_disk = rdev->raid_disk;
 859                 rdev->recovery_offset = 0;
 860         }
 861
 862         clear_bit(FirstUse, &rdev->flags);
 863
 864         return 0;
 865 }
 866
 867 /*
 868  * Analyse superblocks and select the freshest.
 869  */
 870 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
 871 {
 872         int ret;
 873         unsigned redundancy = 0;
 874         struct raid_dev *dev;
 875         struct md_rdev *rdev, *tmp, *freshest;
 876         struct mddev *mddev = &rs->md;
 877
 878         switch (rs->raid_type->level) {
 879         case 1:
 880                 redundancy = rs->md.raid_disks - 1;
 881                 break;
 882         case 4:
 883         case 5:
 884         case 6:
 885                 redundancy = rs->raid_type->parity_devs;
 886                 break;
 887         default:
 888                 ti->error = "Unknown RAID type";
 889                 return -EINVAL;
 890         }
 891
 892         freshest = NULL;
 893         rdev_for_each_safe(rdev, tmp, mddev) {
 894                 if (!rdev->meta_bdev)
 895                         continue;
 896
 897                 ret = super_load(rdev, freshest);
 898
 899                 switch (ret) {
 900                 case 1:
 901                         freshest = rdev;
 902                         break;
 903                 case 0:
 904                         break;
 905                 default:
 906                         dev = container_of(rdev, struct raid_dev, rdev);
 907                         if (redundancy--) {
 908                                 if (dev->meta_dev)
 909                                         dm_put_device(ti, dev->meta_dev);
 910
 911                                 dev->meta_dev = NULL;
 912                                 rdev->meta_bdev = NULL;
 913
 914                                 if (rdev->sb_page)
 915                                         put_page(rdev->sb_page);
 916
 917                                 rdev->sb_page = NULL;
 918
 919                                 rdev->sb_loaded = 0;
 920
 921                                 /*
 922                                  * We might be able to salvage the data device
 923                                  * even though the meta device has failed.  For
 924                                  * now, we behave as though '- -' had been
 925                                  * set for this device in the table.
 926                                  */
 927                                 if (dev->data_dev)
 928                                         dm_put_device(ti, dev->data_dev);
 929
 930                                 dev->data_dev = NULL;
 931                                 rdev->bdev = NULL;
 932
 933                                 list_del(&rdev->same_set);
 934
 935                                 continue;
 936                         }
 937                         ti->error = "Failed to load superblock";
 938                         return ret;
 939                 }
 940         }
 941
 942         if (!freshest)
 943                 return 0;
 944
 945         /*
 946          * Validation of the freshest device provides the source of
 947          * validation for the remaining devices.
 948          */
 949         ti->error = "Unable to assemble array: Invalid superblocks";
 950         if (super_validate(mddev, freshest))
 951                 return -EINVAL;
 952
 953         rdev_for_each(rdev, mddev)
 954                 if ((rdev != freshest) && super_validate(mddev, rdev))
 955                         return -EINVAL;
 956
 957         return 0;
 958 }
 959
 960 /*
 961  * Construct a RAID4/5/6 mapping:
 962  * Args:
 963  *      <raid_type> <#raid_params> <raid_params>                \
 964  *      <#raid_devs> { <meta_dev1> <dev1> .. <meta_devN> <devN> }
 965  *
 966  * <raid_params> varies by <raid_type>.  See 'parse_raid_params' for
 967  * details on possible <raid_params>.
 968  */
 969 static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
 970 {
 971         int ret;
 972         struct raid_type *rt;
 973         unsigned long num_raid_params, num_raid_devs;
 974         struct raid_set *rs = NULL;
 975
 976         /* Must have at least <raid_type> <#raid_params> */
 977         if (argc < 2) {
 978                 ti->error = "Too few arguments";
 979                 return -EINVAL;
 980         }
 981
 982         /* raid type */
 983         rt = get_raid_type(argv[0]);
 984         if (!rt) {
 985                 ti->error = "Unrecognised raid_type";
 986                 return -EINVAL;
 987         }
 988         argc--;
 989         argv++;
 990
 991         /* number of RAID parameters */
 992         if (strict_strtoul(argv[0], 10, &num_raid_params) < 0) {
 993                 ti->error = "Cannot understand number of RAID parameters";
 994                 return -EINVAL;
 995         }
 996         argc--;
 997         argv++;
 998
 999         /* Skip over RAID params for now and find out # of devices */
1000         if (num_raid_params + 1 > argc) {
1001                 ti->error = "Arguments do not agree with counts given";
1002                 return -EINVAL;
1003         }
1004
1005         if ((strict_strtoul(argv[num_raid_params], 10, &num_raid_devs) < 0) ||
1006             (num_raid_devs >= INT_MAX)) {
1007                 ti->error = "Cannot understand number of raid devices";
1008                 return -EINVAL;
1009         }
1010
1011         rs = context_alloc(ti, rt, (unsigned)num_raid_devs);
1012         if (IS_ERR(rs))
1013                 return PTR_ERR(rs);
1014
1015         ret = parse_raid_params(rs, argv, (unsigned)num_raid_params);
1016         if (ret)
1017                 goto bad;
1018
1019         ret = -EINVAL;
1020
1021         argc -= num_raid_params + 1; /* +1: we already have num_raid_devs */
1022         argv += num_raid_params + 1;
1023
1024         if (argc != (num_raid_devs * 2)) {
1025                 ti->error = "Supplied RAID devices does not match the count given";
1026                 goto bad;
1027         }
1028
1029         ret = dev_parms(rs, argv);
1030         if (ret)
1031                 goto bad;
1032
1033         rs->md.sync_super = super_sync;
1034         ret = analyse_superblocks(ti, rs);
1035         if (ret)
1036                 goto bad;
1037
1038         INIT_WORK(&rs->md.event_work, do_table_event);
1039         ti->private = rs;
1040         ti->num_flush_requests = 1;
1041
1042         mutex_lock(&rs->md.reconfig_mutex);
1043         ret = md_run(&rs->md);
1044         rs->md.in_sync = 0; /* Assume already marked dirty */
1045         mutex_unlock(&rs->md.reconfig_mutex);
1046
1047         if (ret) {
1048                 ti->error = "Fail to run raid array";
1049                 goto bad;
1050         }
1051
1052         rs->callbacks.congested_fn = raid_is_congested;
1053         dm_table_add_target_callbacks(ti->table, &rs->callbacks);
1054
1055         mddev_suspend(&rs->md);
1056         return 0;
1057
1058 bad:
1059         context_free(rs);
1060
1061         return ret;
1062 }
1063
1064 static void raid_dtr(struct dm_target *ti)
1065 {
1066         struct raid_set *rs = ti->private;
1067
1068         list_del_init(&rs->callbacks.list);
1069         md_stop(&rs->md);
1070         context_free(rs);
1071 }
1072
1073 static int raid_map(struct dm_target *ti, struct bio *bio, union map_info *map_context)
1074 {
1075         struct raid_set *rs = ti->private;
1076         struct mddev *mddev = &rs->md;
1077
1078         mddev->pers->make_request(mddev, bio);
1079
1080         return DM_MAPIO_SUBMITTED;
1081 }
1082
1083 static int raid_status(struct dm_target *ti, status_type_t type,
1084                        char *result, unsigned maxlen)
1085 {
1086         struct raid_set *rs = ti->private;
1087         unsigned raid_param_cnt = 1; /* at least 1 for chunksize */
1088         unsigned sz = 0;
1089         int i, array_in_sync = 0;
1090         sector_t sync;
1091
1092         switch (type) {
1093         case STATUSTYPE_INFO:
1094                 DMEMIT("%s %d ", rs->raid_type->name, rs->md.raid_disks);
1095
1096                 if (test_bit(MD_RECOVERY_RUNNING, &rs->md.recovery))
1097                         sync = rs->md.curr_resync_completed;
1098                 else
1099                         sync = rs->md.recovery_cp;
1100
1101                 if (sync >= rs->md.resync_max_sectors) {
1102                         array_in_sync = 1;
1103                         sync = rs->md.resync_max_sectors;
1104                 } else {
1105                         /*
1106                          * The array may be doing an initial sync, or it may
1107                          * be rebuilding individual components.  If all the
1108                          * devices are In_sync, then it is the array that is
1109                          * being initialized.
1110                          */
1111                         for (i = 0; i < rs->md.raid_disks; i++)
1112                                 if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
1113                                         array_in_sync = 1;
1114                 }
1115                 /*
1116                  * Status characters:
1117                  *  'D' = Dead/Failed device
1118                  *  'a' = Alive but not in-sync
1119                  *  'A' = Alive and in-sync
1120                  */
1121                 for (i = 0; i < rs->md.raid_disks; i++) {
1122                         if (test_bit(Faulty, &rs->dev[i].rdev.flags))
1123                                 DMEMIT("D");
1124                         else if (!array_in_sync ||
1125                                  !test_bit(In_sync, &rs->dev[i].rdev.flags))
1126                                 DMEMIT("a");
1127                         else
1128                                 DMEMIT("A");
1129                 }
1130
1131                 /*
1132                  * In-sync ratio:
1133                  *  The in-sync ratio shows the progress of:
1134                  *   - Initializing the array
1135                  *   - Rebuilding a subset of devices of the array
1136                  *  The user can distinguish between the two by referring
1137                  *  to the status characters.
1138                  */
1139                 DMEMIT(" %llu/%llu",
1140                        (unsigned long long) sync,
1141                        (unsigned long long) rs->md.resync_max_sectors);
1142
1143                 break;
1144         case STATUSTYPE_TABLE:
1145                 /* The string you would use to construct this array */
1146                 for (i = 0; i < rs->md.raid_disks; i++) {
1147                         if ((rs->print_flags & DMPF_REBUILD) &&
1148                             rs->dev[i].data_dev &&
1149                             !test_bit(In_sync, &rs->dev[i].rdev.flags))
1150                                 raid_param_cnt += 2; /* for rebuilds */
1151                         if (rs->dev[i].data_dev &&
1152                             test_bit(WriteMostly, &rs->dev[i].rdev.flags))
1153                                 raid_param_cnt += 2;
1154                 }
1155
1156                 raid_param_cnt += (hweight32(rs->print_flags & ~DMPF_REBUILD) * 2);
1157                 if (rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC))
1158                         raid_param_cnt--;
1159
1160                 DMEMIT("%s %u %u", rs->raid_type->name,
1161                        raid_param_cnt, rs->md.chunk_sectors);
1162
1163                 if ((rs->print_flags & DMPF_SYNC) &&
1164                     (rs->md.recovery_cp == MaxSector))
1165                         DMEMIT(" sync");
1166                 if (rs->print_flags & DMPF_NOSYNC)
1167                         DMEMIT(" nosync");
1168
1169                 for (i = 0; i < rs->md.raid_disks; i++)
1170                         if ((rs->print_flags & DMPF_REBUILD) &&
1171                             rs->dev[i].data_dev &&
1172                             !test_bit(In_sync, &rs->dev[i].rdev.flags))
1173                                 DMEMIT(" rebuild %u", i);
1174
1175                 if (rs->print_flags & DMPF_DAEMON_SLEEP)
1176                         DMEMIT(" daemon_sleep %lu",
1177                                rs->md.bitmap_info.daemon_sleep);
1178
1179                 if (rs->print_flags & DMPF_MIN_RECOVERY_RATE)
1180                         DMEMIT(" min_recovery_rate %d", rs->md.sync_speed_min);
1181
1182                 if (rs->print_flags & DMPF_MAX_RECOVERY_RATE)
1183                         DMEMIT(" max_recovery_rate %d", rs->md.sync_speed_max);
1184
1185                 for (i = 0; i < rs->md.raid_disks; i++)
1186                         if (rs->dev[i].data_dev &&
1187                             test_bit(WriteMostly, &rs->dev[i].rdev.flags))
1188                                 DMEMIT(" write_mostly %u", i);
1189
1190                 if (rs->print_flags & DMPF_MAX_WRITE_BEHIND)
1191                         DMEMIT(" max_write_behind %lu",
1192                                rs->md.bitmap_info.max_write_behind);
1193
1194                 if (rs->print_flags & DMPF_STRIPE_CACHE) {
1195                         struct r5conf *conf = rs->md.private;
1196
1197                         /* convert from kiB to sectors */
1198                         DMEMIT(" stripe_cache %d",
1199                                conf ? conf->max_nr_stripes * 2 : 0);
1200                 }
1201
1202                 if (rs->print_flags & DMPF_REGION_SIZE)
1203                         DMEMIT(" region_size %lu",
1204                                rs->md.bitmap_info.chunksize >> 9);
1205
1206                 DMEMIT(" %d", rs->md.raid_disks);
1207                 for (i = 0; i < rs->md.raid_disks; i++) {
1208                         if (rs->dev[i].meta_dev)
1209                                 DMEMIT(" %s", rs->dev[i].meta_dev->name);
1210                         else
1211                                 DMEMIT(" -");
1212
1213                         if (rs->dev[i].data_dev)
1214                                 DMEMIT(" %s", rs->dev[i].data_dev->name);
1215                         else
1216                                 DMEMIT(" -");
1217                 }
1218         }
1219
1220         return 0;
1221 }
1222
1223 static int raid_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
1224 {
1225         struct raid_set *rs = ti->private;
1226         unsigned i;
1227         int ret = 0;
1228
1229         for (i = 0; !ret && i < rs->md.raid_disks; i++)
1230                 if (rs->dev[i].data_dev)
1231                         ret = fn(ti,
1232                                  rs->dev[i].data_dev,
1233                                  0, /* No offset on data devs */
1234                                  rs->md.dev_sectors,
1235                                  data);
1236
1237         return ret;
1238 }
1239
1240 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
1241 {
1242         struct raid_set *rs = ti->private;
1243         unsigned chunk_size = rs->md.chunk_sectors << 9;
1244         struct r5conf *conf = rs->md.private;
1245
1246         blk_limits_io_min(limits, chunk_size);
1247         blk_limits_io_opt(limits, chunk_size * (conf->raid_disks - conf->max_degraded));
1248 }
1249
1250 static void raid_presuspend(struct dm_target *ti)
1251 {
1252         struct raid_set *rs = ti->private;
1253
1254         md_stop_writes(&rs->md);
1255 }
1256
1257 static void raid_postsuspend(struct dm_target *ti)
1258 {
1259         struct raid_set *rs = ti->private;
1260
1261         mddev_suspend(&rs->md);
1262 }
1263
1264 static void raid_resume(struct dm_target *ti)
1265 {
1266         struct raid_set *rs = ti->private;
1267
1268         set_bit(MD_CHANGE_DEVS, &rs->md.flags);
1269         if (!rs->bitmap_loaded) {
1270                 bitmap_load(&rs->md);
1271                 rs->bitmap_loaded = 1;
1272         }
1273
1274         clear_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
1275         mddev_resume(&rs->md);
1276 }
1277
1278 static struct target_type raid_target = {
1279         .name = "raid",
1280         .version = {1, 2, 0},
1281         .module = THIS_MODULE,
1282         .ctr = raid_ctr,
1283         .dtr = raid_dtr,
1284         .map = raid_map,
1285         .status = raid_status,
1286         .iterate_devices = raid_iterate_devices,
1287         .io_hints = raid_io_hints,
1288         .presuspend = raid_presuspend,
1289         .postsuspend = raid_postsuspend,
1290         .resume = raid_resume,
1291 };
1292
1293 static int __init dm_raid_init(void)
1294 {
1295         return dm_register_target(&raid_target);
1296 }
1297
1298 static void __exit dm_raid_exit(void)
1299 {
1300         dm_unregister_target(&raid_target);
1301 }
1302
1303 module_init(dm_raid_init);
1304 module_exit(dm_raid_exit);
1305
1306 MODULE_DESCRIPTION(DM_NAME " raid4/5/6 target");
1307 MODULE_ALIAS("dm-raid4");
1308 MODULE_ALIAS("dm-raid5");
1309 MODULE_ALIAS("dm-raid6");
1310 MODULE_AUTHOR("Neil Brown <[email protected]>");
1311 MODULE_LICENSE("GPL");