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