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                 set_bit(Faulty, &rdev->flags);
 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         struct md_rdev *r;
 618         uint64_t failed_devices;
 619         struct dm_raid_superblock *sb;
 620
 621         sb = page_address(rdev->sb_page);
 622         failed_devices = le64_to_cpu(sb->failed_devices);
 623
 624         rdev_for_each(r, mddev)
 625                 if ((r->raid_disk >= 0) && test_bit(Faulty, &r->flags))
 626                         failed_devices |= (1ULL << r->raid_disk);
 627
 628         memset(sb, 0, sizeof(*sb));
 629
 630         sb->magic = cpu_to_le32(DM_RAID_MAGIC);
 631         sb->features = cpu_to_le32(0);  /* No features yet */
 632
 633         sb->num_devices = cpu_to_le32(mddev->raid_disks);
 634         sb->array_position = cpu_to_le32(rdev->raid_disk);
 635
 636         sb->events = cpu_to_le64(mddev->events);
 637         sb->failed_devices = cpu_to_le64(failed_devices);
 638
 639         sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
 640         sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
 641
 642         sb->level = cpu_to_le32(mddev->level);
 643         sb->layout = cpu_to_le32(mddev->layout);
 644         sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
 645 }
 646
 647 /*
 648  * super_load
 649  *
 650  * This function creates a superblock if one is not found on the device
 651  * and will decide which superblock to use if there's a choice.
 652  *
 653  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
 654  */
 655 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
 656 {
 657         int ret;
 658         struct dm_raid_superblock *sb;
 659         struct dm_raid_superblock *refsb;
 660         uint64_t events_sb, events_refsb;
 661
 662         rdev->sb_start = 0;
 663         rdev->sb_size = sizeof(*sb);
 664
 665         ret = read_disk_sb(rdev, rdev->sb_size);
 666         if (ret)
 667                 return ret;
 668
 669         sb = page_address(rdev->sb_page);
 670
 671         /*
 672          * Two cases that we want to write new superblocks and rebuild:
 673          * 1) New device (no matching magic number)
 674          * 2) Device specified for rebuild (!In_sync w/ offset == 0)
 675          */
 676         if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
 677             (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
 678                 super_sync(rdev->mddev, rdev);
 679
 680                 set_bit(FirstUse, &rdev->flags);
 681
 682                 /* Force writing of superblocks to disk */
 683                 set_bit(MD_CHANGE_DEVS, &rdev->mddev->flags);
 684
 685                 /* Any superblock is better than none, choose that if given */
 686                 return refdev ? 0 : 1;
 687         }
 688
 689         if (!refdev)
 690                 return 1;
 691
 692         events_sb = le64_to_cpu(sb->events);
 693
 694         refsb = page_address(refdev->sb_page);
 695         events_refsb = le64_to_cpu(refsb->events);
 696
 697         return (events_sb > events_refsb) ? 1 : 0;
 698 }
 699
 700 static int super_init_validation(struct mddev *mddev, struct md_rdev *rdev)
 701 {
 702         int role;
 703         struct raid_set *rs = container_of(mddev, struct raid_set, md);
 704         uint64_t events_sb;
 705         uint64_t failed_devices;
 706         struct dm_raid_superblock *sb;
 707         uint32_t new_devs = 0;
 708         uint32_t rebuilds = 0;
 709         struct md_rdev *r;
 710         struct dm_raid_superblock *sb2;
 711
 712         sb = page_address(rdev->sb_page);
 713         events_sb = le64_to_cpu(sb->events);
 714         failed_devices = le64_to_cpu(sb->failed_devices);
 715
 716         /*
 717          * Initialise to 1 if this is a new superblock.
 718          */
 719         mddev->events = events_sb ? : 1;
 720
 721         /*
 722          * Reshaping is not currently allowed
 723          */
 724         if ((le32_to_cpu(sb->level) != mddev->level) ||
 725             (le32_to_cpu(sb->layout) != mddev->layout) ||
 726             (le32_to_cpu(sb->stripe_sectors) != mddev->chunk_sectors)) {
 727                 DMERR("Reshaping arrays not yet supported.");
 728                 return -EINVAL;
 729         }
 730
 731         /* We can only change the number of devices in RAID1 right now */
 732         if ((rs->raid_type->level != 1) &&
 733             (le32_to_cpu(sb->num_devices) != mddev->raid_disks)) {
 734                 DMERR("Reshaping arrays not yet supported.");
 735                 return -EINVAL;
 736         }
 737
 738         if (!(rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC)))
 739                 mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
 740
 741         /*
 742          * During load, we set FirstUse if a new superblock was written.
 743          * There are two reasons we might not have a superblock:
 744          * 1) The array is brand new - in which case, all of the
 745          *    devices must have their In_sync bit set.  Also,
 746          *    recovery_cp must be 0, unless forced.
 747          * 2) This is a new device being added to an old array
 748          *    and the new device needs to be rebuilt - in which
 749          *    case the In_sync bit will /not/ be set and
 750          *    recovery_cp must be MaxSector.
 751          */
 752         rdev_for_each(r, mddev) {
 753                 if (!test_bit(In_sync, &r->flags)) {
 754                         DMINFO("Device %d specified for rebuild: "
 755                                "Clearing superblock", r->raid_disk);
 756                         rebuilds++;
 757                 } else if (test_bit(FirstUse, &r->flags))
 758                         new_devs++;
 759         }
 760
 761         if (!rebuilds) {
 762                 if (new_devs == mddev->raid_disks) {
 763                         DMINFO("Superblocks created for new array");
 764                         set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
 765                 } else if (new_devs) {
 766                         DMERR("New device injected "
 767                               "into existing array without 'rebuild' "
 768                               "parameter specified");
 769                         return -EINVAL;
 770                 }
 771         } else if (new_devs) {
 772                 DMERR("'rebuild' devices cannot be "
 773                       "injected into an array with other first-time devices");
 774                 return -EINVAL;
 775         } else if (mddev->recovery_cp != MaxSector) {
 776                 DMERR("'rebuild' specified while array is not in-sync");
 777                 return -EINVAL;
 778         }
 779
 780         /*
 781          * Now we set the Faulty bit for those devices that are
 782          * recorded in the superblock as failed.
 783          */
 784         rdev_for_each(r, mddev) {
 785                 if (!r->sb_page)
 786                         continue;
 787                 sb2 = page_address(r->sb_page);
 788                 sb2->failed_devices = 0;
 789
 790                 /*
 791                  * Check for any device re-ordering.
 792                  */
 793                 if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
 794                         role = le32_to_cpu(sb2->array_position);
 795                         if (role != r->raid_disk) {
 796                                 if (rs->raid_type->level != 1) {
 797                                         rs->ti->error = "Cannot change device "
 798                                                 "positions in RAID array";
 799                                         return -EINVAL;
 800                                 }
 801                                 DMINFO("RAID1 device #%d now at position #%d",
 802                                        role, r->raid_disk);
 803                         }
 804
 805                         /*
 806                          * Partial recovery is performed on
 807                          * returning failed devices.
 808                          */
 809                         if (failed_devices & (1 << role))
 810                                 set_bit(Faulty, &r->flags);
 811                 }
 812         }
 813
 814         return 0;
 815 }
 816
 817 static int super_validate(struct mddev *mddev, struct md_rdev *rdev)
 818 {
 819         struct dm_raid_superblock *sb = page_address(rdev->sb_page);
 820
 821         /*
 822          * If mddev->events is not set, we know we have not yet initialized
 823          * the array.
 824          */
 825         if (!mddev->events && super_init_validation(mddev, rdev))
 826                 return -EINVAL;
 827
 828         mddev->bitmap_info.offset = 4096 >> 9; /* Enable bitmap creation */
 829         rdev->mddev->bitmap_info.default_offset = 4096 >> 9;
 830         if (!test_bit(FirstUse, &rdev->flags)) {
 831                 rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
 832                 if (rdev->recovery_offset != MaxSector)
 833                         clear_bit(In_sync, &rdev->flags);
 834         }
 835
 836         /*
 837          * If a device comes back, set it as not In_sync and no longer faulty.
 838          */
 839         if (test_bit(Faulty, &rdev->flags)) {
 840                 clear_bit(Faulty, &rdev->flags);
 841                 clear_bit(In_sync, &rdev->flags);
 842                 rdev->saved_raid_disk = rdev->raid_disk;
 843                 rdev->recovery_offset = 0;
 844         }
 845
 846         clear_bit(FirstUse, &rdev->flags);
 847
 848         return 0;
 849 }
 850
 851 /*
 852  * Analyse superblocks and select the freshest.
 853  */
 854 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
 855 {
 856         int ret;
 857         unsigned redundancy = 0;
 858         struct raid_dev *dev;
 859         struct md_rdev *rdev, *tmp, *freshest;
 860         struct mddev *mddev = &rs->md;
 861
 862         switch (rs->raid_type->level) {
 863         case 1:
 864                 redundancy = rs->md.raid_disks - 1;
 865                 break;
 866         case 4:
 867         case 5:
 868         case 6:
 869                 redundancy = rs->raid_type->parity_devs;
 870                 break;
 871         default:
 872                 ti->error = "Unknown RAID type";
 873                 return -EINVAL;
 874         }
 875
 876         freshest = NULL;
 877         rdev_for_each_safe(rdev, tmp, mddev) {
 878                 if (!rdev->meta_bdev)
 879                         continue;
 880
 881                 ret = super_load(rdev, freshest);
 882
 883                 switch (ret) {
 884                 case 1:
 885                         freshest = rdev;
 886                         break;
 887                 case 0:
 888                         break;
 889                 default:
 890                         dev = container_of(rdev, struct raid_dev, rdev);
 891                         if (redundancy--) {
 892                                 if (dev->meta_dev)
 893                                         dm_put_device(ti, dev->meta_dev);
 894
 895                                 dev->meta_dev = NULL;
 896                                 rdev->meta_bdev = NULL;
 897
 898                                 if (rdev->sb_page)
 899                                         put_page(rdev->sb_page);
 900
 901                                 rdev->sb_page = NULL;
 902
 903                                 rdev->sb_loaded = 0;
 904
 905                                 /*
 906                                  * We might be able to salvage the data device
 907                                  * even though the meta device has failed.  For
 908                                  * now, we behave as though '- -' had been
 909                                  * set for this device in the table.
 910                                  */
 911                                 if (dev->data_dev)
 912                                         dm_put_device(ti, dev->data_dev);
 913
 914                                 dev->data_dev = NULL;
 915                                 rdev->bdev = NULL;
 916
 917                                 list_del(&rdev->same_set);
 918
 919                                 continue;
 920                         }
 921                         ti->error = "Failed to load superblock";
 922                         return ret;
 923                 }
 924         }
 925
 926         if (!freshest)
 927                 return 0;
 928
 929         /*
 930          * Validation of the freshest device provides the source of
 931          * validation for the remaining devices.
 932          */
 933         ti->error = "Unable to assemble array: Invalid superblocks";
 934         if (super_validate(mddev, freshest))
 935                 return -EINVAL;
 936
 937         rdev_for_each(rdev, mddev)
 938                 if ((rdev != freshest) && super_validate(mddev, rdev))
 939                         return -EINVAL;
 940
 941         return 0;
 942 }
 943
 944 /*
 945  * Construct a RAID4/5/6 mapping:
 946  * Args:
 947  *      <raid_type> <#raid_params> <raid_params>                \
 948  *      <#raid_devs> { <meta_dev1> <dev1> .. <meta_devN> <devN> }
 949  *
 950  * <raid_params> varies by <raid_type>.  See 'parse_raid_params' for
 951  * details on possible <raid_params>.
 952  */
 953 static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
 954 {
 955         int ret;
 956         struct raid_type *rt;
 957         unsigned long num_raid_params, num_raid_devs;
 958         struct raid_set *rs = NULL;
 959
 960         /* Must have at least <raid_type> <#raid_params> */
 961         if (argc < 2) {
 962                 ti->error = "Too few arguments";
 963                 return -EINVAL;
 964         }
 965
 966         /* raid type */
 967         rt = get_raid_type(argv[0]);
 968         if (!rt) {
 969                 ti->error = "Unrecognised raid_type";
 970                 return -EINVAL;
 971         }
 972         argc--;
 973         argv++;
 974
 975         /* number of RAID parameters */
 976         if (strict_strtoul(argv[0], 10, &num_raid_params) < 0) {
 977                 ti->error = "Cannot understand number of RAID parameters";
 978                 return -EINVAL;
 979         }
 980         argc--;
 981         argv++;
 982
 983         /* Skip over RAID params for now and find out # of devices */
 984         if (num_raid_params + 1 > argc) {
 985                 ti->error = "Arguments do not agree with counts given";
 986                 return -EINVAL;
 987         }
 988
 989         if ((strict_strtoul(argv[num_raid_params], 10, &num_raid_devs) < 0) ||
 990             (num_raid_devs >= INT_MAX)) {
 991                 ti->error = "Cannot understand number of raid devices";
 992                 return -EINVAL;
 993         }
 994
 995         rs = context_alloc(ti, rt, (unsigned)num_raid_devs);
 996         if (IS_ERR(rs))
 997                 return PTR_ERR(rs);
 998
 999         ret = parse_raid_params(rs, argv, (unsigned)num_raid_params);
1000         if (ret)
1001                 goto bad;
1002
1003         ret = -EINVAL;
1004
1005         argc -= num_raid_params + 1; /* +1: we already have num_raid_devs */
1006         argv += num_raid_params + 1;
1007
1008         if (argc != (num_raid_devs * 2)) {
1009                 ti->error = "Supplied RAID devices does not match the count given";
1010                 goto bad;
1011         }
1012
1013         ret = dev_parms(rs, argv);
1014         if (ret)
1015                 goto bad;
1016
1017         rs->md.sync_super = super_sync;
1018         ret = analyse_superblocks(ti, rs);
1019         if (ret)
1020                 goto bad;
1021
1022         INIT_WORK(&rs->md.event_work, do_table_event);
1023         ti->private = rs;
1024         ti->num_flush_requests = 1;
1025
1026         mutex_lock(&rs->md.reconfig_mutex);
1027         ret = md_run(&rs->md);
1028         rs->md.in_sync = 0; /* Assume already marked dirty */
1029         mutex_unlock(&rs->md.reconfig_mutex);
1030
1031         if (ret) {
1032                 ti->error = "Fail to run raid array";
1033                 goto bad;
1034         }
1035
1036         rs->callbacks.congested_fn = raid_is_congested;
1037         dm_table_add_target_callbacks(ti->table, &rs->callbacks);
1038
1039         mddev_suspend(&rs->md);
1040         return 0;
1041
1042 bad:
1043         context_free(rs);
1044
1045         return ret;
1046 }
1047
1048 static void raid_dtr(struct dm_target *ti)
1049 {
1050         struct raid_set *rs = ti->private;
1051
1052         list_del_init(&rs->callbacks.list);
1053         md_stop(&rs->md);
1054         context_free(rs);
1055 }
1056
1057 static int raid_map(struct dm_target *ti, struct bio *bio, union map_info *map_context)
1058 {
1059         struct raid_set *rs = ti->private;
1060         struct mddev *mddev = &rs->md;
1061
1062         mddev->pers->make_request(mddev, bio);
1063
1064         return DM_MAPIO_SUBMITTED;
1065 }
1066
1067 static int raid_status(struct dm_target *ti, status_type_t type,
1068                        char *result, unsigned maxlen)
1069 {
1070         struct raid_set *rs = ti->private;
1071         unsigned raid_param_cnt = 1; /* at least 1 for chunksize */
1072         unsigned sz = 0;
1073         int i, array_in_sync = 0;
1074         sector_t sync;
1075
1076         switch (type) {
1077         case STATUSTYPE_INFO:
1078                 DMEMIT("%s %d ", rs->raid_type->name, rs->md.raid_disks);
1079
1080                 if (test_bit(MD_RECOVERY_RUNNING, &rs->md.recovery))
1081                         sync = rs->md.curr_resync_completed;
1082                 else
1083                         sync = rs->md.recovery_cp;
1084
1085                 if (sync >= rs->md.resync_max_sectors) {
1086                         array_in_sync = 1;
1087                         sync = rs->md.resync_max_sectors;
1088                 } else {
1089                         /*
1090                          * The array may be doing an initial sync, or it may
1091                          * be rebuilding individual components.  If all the
1092                          * devices are In_sync, then it is the array that is
1093                          * being initialized.
1094                          */
1095                         for (i = 0; i < rs->md.raid_disks; i++)
1096                                 if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
1097                                         array_in_sync = 1;
1098                 }
1099                 /*
1100                  * Status characters:
1101                  *  'D' = Dead/Failed device
1102                  *  'a' = Alive but not in-sync
1103                  *  'A' = Alive and in-sync
1104                  */
1105                 for (i = 0; i < rs->md.raid_disks; i++) {
1106                         if (test_bit(Faulty, &rs->dev[i].rdev.flags))
1107                                 DMEMIT("D");
1108                         else if (!array_in_sync ||
1109                                  !test_bit(In_sync, &rs->dev[i].rdev.flags))
1110                                 DMEMIT("a");
1111                         else
1112                                 DMEMIT("A");
1113                 }
1114
1115                 /*
1116                  * In-sync ratio:
1117                  *  The in-sync ratio shows the progress of:
1118                  *   - Initializing the array
1119                  *   - Rebuilding a subset of devices of the array
1120                  *  The user can distinguish between the two by referring
1121                  *  to the status characters.
1122                  */
1123                 DMEMIT(" %llu/%llu",
1124                        (unsigned long long) sync,
1125                        (unsigned long long) rs->md.resync_max_sectors);
1126
1127                 break;
1128         case STATUSTYPE_TABLE:
1129                 /* The string you would use to construct this array */
1130                 for (i = 0; i < rs->md.raid_disks; i++) {
1131                         if ((rs->print_flags & DMPF_REBUILD) &&
1132                             rs->dev[i].data_dev &&
1133                             !test_bit(In_sync, &rs->dev[i].rdev.flags))
1134                                 raid_param_cnt += 2; /* for rebuilds */
1135                         if (rs->dev[i].data_dev &&
1136                             test_bit(WriteMostly, &rs->dev[i].rdev.flags))
1137                                 raid_param_cnt += 2;
1138                 }
1139
1140                 raid_param_cnt += (hweight32(rs->print_flags & ~DMPF_REBUILD) * 2);
1141                 if (rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC))
1142                         raid_param_cnt--;
1143
1144                 DMEMIT("%s %u %u", rs->raid_type->name,
1145                        raid_param_cnt, rs->md.chunk_sectors);
1146
1147                 if ((rs->print_flags & DMPF_SYNC) &&
1148                     (rs->md.recovery_cp == MaxSector))
1149                         DMEMIT(" sync");
1150                 if (rs->print_flags & DMPF_NOSYNC)
1151                         DMEMIT(" nosync");
1152
1153                 for (i = 0; i < rs->md.raid_disks; i++)
1154                         if ((rs->print_flags & DMPF_REBUILD) &&
1155                             rs->dev[i].data_dev &&
1156                             !test_bit(In_sync, &rs->dev[i].rdev.flags))
1157                                 DMEMIT(" rebuild %u", i);
1158
1159                 if (rs->print_flags & DMPF_DAEMON_SLEEP)
1160                         DMEMIT(" daemon_sleep %lu",
1161                                rs->md.bitmap_info.daemon_sleep);
1162
1163                 if (rs->print_flags & DMPF_MIN_RECOVERY_RATE)
1164                         DMEMIT(" min_recovery_rate %d", rs->md.sync_speed_min);
1165
1166                 if (rs->print_flags & DMPF_MAX_RECOVERY_RATE)
1167                         DMEMIT(" max_recovery_rate %d", rs->md.sync_speed_max);
1168
1169                 for (i = 0; i < rs->md.raid_disks; i++)
1170                         if (rs->dev[i].data_dev &&
1171                             test_bit(WriteMostly, &rs->dev[i].rdev.flags))
1172                                 DMEMIT(" write_mostly %u", i);
1173
1174                 if (rs->print_flags & DMPF_MAX_WRITE_BEHIND)
1175                         DMEMIT(" max_write_behind %lu",
1176                                rs->md.bitmap_info.max_write_behind);
1177
1178                 if (rs->print_flags & DMPF_STRIPE_CACHE) {
1179                         struct r5conf *conf = rs->md.private;
1180
1181                         /* convert from kiB to sectors */
1182                         DMEMIT(" stripe_cache %d",
1183                                conf ? conf->max_nr_stripes * 2 : 0);
1184                 }
1185
1186                 if (rs->print_flags & DMPF_REGION_SIZE)
1187                         DMEMIT(" region_size %lu",
1188                                rs->md.bitmap_info.chunksize >> 9);
1189
1190                 DMEMIT(" %d", rs->md.raid_disks);
1191                 for (i = 0; i < rs->md.raid_disks; i++) {
1192                         if (rs->dev[i].meta_dev)
1193                                 DMEMIT(" %s", rs->dev[i].meta_dev->name);
1194                         else
1195                                 DMEMIT(" -");
1196
1197                         if (rs->dev[i].data_dev)
1198                                 DMEMIT(" %s", rs->dev[i].data_dev->name);
1199                         else
1200                                 DMEMIT(" -");
1201                 }
1202         }
1203
1204         return 0;
1205 }
1206
1207 static int raid_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
1208 {
1209         struct raid_set *rs = ti->private;
1210         unsigned i;
1211         int ret = 0;
1212
1213         for (i = 0; !ret && i < rs->md.raid_disks; i++)
1214                 if (rs->dev[i].data_dev)
1215                         ret = fn(ti,
1216                                  rs->dev[i].data_dev,
1217                                  0, /* No offset on data devs */
1218                                  rs->md.dev_sectors,
1219                                  data);
1220
1221         return ret;
1222 }
1223
1224 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
1225 {
1226         struct raid_set *rs = ti->private;
1227         unsigned chunk_size = rs->md.chunk_sectors << 9;
1228         struct r5conf *conf = rs->md.private;
1229
1230         blk_limits_io_min(limits, chunk_size);
1231         blk_limits_io_opt(limits, chunk_size * (conf->raid_disks - conf->max_degraded));
1232 }
1233
1234 static void raid_presuspend(struct dm_target *ti)
1235 {
1236         struct raid_set *rs = ti->private;
1237
1238         md_stop_writes(&rs->md);
1239 }
1240
1241 static void raid_postsuspend(struct dm_target *ti)
1242 {
1243         struct raid_set *rs = ti->private;
1244
1245         mddev_suspend(&rs->md);
1246 }
1247
1248 static void raid_resume(struct dm_target *ti)
1249 {
1250         struct raid_set *rs = ti->private;
1251
1252         if (!rs->bitmap_loaded) {
1253                 bitmap_load(&rs->md);
1254                 rs->bitmap_loaded = 1;
1255         } else
1256                 md_wakeup_thread(rs->md.thread);
1257
1258         mddev_resume(&rs->md);
1259 }
1260
1261 static struct target_type raid_target = {
1262         .name = "raid",
1263         .version = {1, 2, 0},
1264         .module = THIS_MODULE,
1265         .ctr = raid_ctr,
1266         .dtr = raid_dtr,
1267         .map = raid_map,
1268         .status = raid_status,
1269         .iterate_devices = raid_iterate_devices,
1270         .io_hints = raid_io_hints,
1271         .presuspend = raid_presuspend,
1272         .postsuspend = raid_postsuspend,
1273         .resume = raid_resume,
1274 };
1275
1276 static int __init dm_raid_init(void)
1277 {
1278         return dm_register_target(&raid_target);
1279 }
1280
1281 static void __exit dm_raid_exit(void)
1282 {
1283         dm_unregister_target(&raid_target);
1284 }
1285
1286 module_init(dm_raid_init);
1287 module_exit(dm_raid_exit);
1288
1289 MODULE_DESCRIPTION(DM_NAME " raid4/5/6 target");
1290 MODULE_ALIAS("dm-raid4");
1291 MODULE_ALIAS("dm-raid5");
1292 MODULE_ALIAS("dm-raid6");
1293 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
1294 MODULE_LICENSE("GPL");