linux/drivers/md/dm-raid.c
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   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 "raid10.h"
  15#include "bitmap.h"
  16
  17#include <linux/device-mapper.h>
  18
  19#define DM_MSG_PREFIX "raid"
  20
  21/*
  22 * The following flags are used by dm-raid.c to set up the array state.
  23 * They must be cleared before md_run is called.
  24 */
  25#define FirstUse 10             /* rdev flag */
  26
  27struct raid_dev {
  28        /*
  29         * Two DM devices, one to hold metadata and one to hold the
  30         * actual data/parity.  The reason for this is to not confuse
  31         * ti->len and give more flexibility in altering size and
  32         * characteristics.
  33         *
  34         * While it is possible for this device to be associated
  35         * with a different physical device than the data_dev, it
  36         * is intended for it to be the same.
  37         *    |--------- Physical Device ---------|
  38         *    |- meta_dev -|------ data_dev ------|
  39         */
  40        struct dm_dev *meta_dev;
  41        struct dm_dev *data_dev;
  42        struct md_rdev rdev;
  43};
  44
  45/*
  46 * Flags for rs->print_flags field.
  47 */
  48#define DMPF_SYNC              0x1
  49#define DMPF_NOSYNC            0x2
  50#define DMPF_REBUILD           0x4
  51#define DMPF_DAEMON_SLEEP      0x8
  52#define DMPF_MIN_RECOVERY_RATE 0x10
  53#define DMPF_MAX_RECOVERY_RATE 0x20
  54#define DMPF_MAX_WRITE_BEHIND  0x40
  55#define DMPF_STRIPE_CACHE      0x80
  56#define DMPF_REGION_SIZE       0x100
  57#define DMPF_RAID10_COPIES     0x200
  58#define DMPF_RAID10_FORMAT     0x400
  59
  60struct raid_set {
  61        struct dm_target *ti;
  62
  63        uint32_t bitmap_loaded;
  64        uint32_t print_flags;
  65
  66        struct mddev md;
  67        struct raid_type *raid_type;
  68        struct dm_target_callbacks callbacks;
  69
  70        struct raid_dev dev[0];
  71};
  72
  73/* Supported raid types and properties. */
  74static struct raid_type {
  75        const char *name;               /* RAID algorithm. */
  76        const char *descr;              /* Descriptor text for logging. */
  77        const unsigned parity_devs;     /* # of parity devices. */
  78        const unsigned minimal_devs;    /* minimal # of devices in set. */
  79        const unsigned level;           /* RAID level. */
  80        const unsigned algorithm;       /* RAID algorithm. */
  81} raid_types[] = {
  82        {"raid1",    "RAID1 (mirroring)",               0, 2, 1, 0 /* NONE */},
  83        {"raid10",   "RAID10 (striped mirrors)",        0, 2, 10, UINT_MAX /* Varies */},
  84        {"raid4",    "RAID4 (dedicated parity disk)",   1, 2, 5, ALGORITHM_PARITY_0},
  85        {"raid5_la", "RAID5 (left asymmetric)",         1, 2, 5, ALGORITHM_LEFT_ASYMMETRIC},
  86        {"raid5_ra", "RAID5 (right asymmetric)",        1, 2, 5, ALGORITHM_RIGHT_ASYMMETRIC},
  87        {"raid5_ls", "RAID5 (left symmetric)",          1, 2, 5, ALGORITHM_LEFT_SYMMETRIC},
  88        {"raid5_rs", "RAID5 (right symmetric)",         1, 2, 5, ALGORITHM_RIGHT_SYMMETRIC},
  89        {"raid6_zr", "RAID6 (zero restart)",            2, 4, 6, ALGORITHM_ROTATING_ZERO_RESTART},
  90        {"raid6_nr", "RAID6 (N restart)",               2, 4, 6, ALGORITHM_ROTATING_N_RESTART},
  91        {"raid6_nc", "RAID6 (N continue)",              2, 4, 6, ALGORITHM_ROTATING_N_CONTINUE}
  92};
  93
  94static unsigned raid10_md_layout_to_copies(int layout)
  95{
  96        return layout & 0xFF;
  97}
  98
  99static int raid10_format_to_md_layout(char *format, unsigned copies)
 100{
 101        /* 1 "far" copy, and 'copies' "near" copies */
 102        return (1 << 8) | (copies & 0xFF);
 103}
 104
 105static struct raid_type *get_raid_type(char *name)
 106{
 107        int i;
 108
 109        for (i = 0; i < ARRAY_SIZE(raid_types); i++)
 110                if (!strcmp(raid_types[i].name, name))
 111                        return &raid_types[i];
 112
 113        return NULL;
 114}
 115
 116static struct raid_set *context_alloc(struct dm_target *ti, struct raid_type *raid_type, unsigned raid_devs)
 117{
 118        unsigned i;
 119        struct raid_set *rs;
 120
 121        if (raid_devs <= raid_type->parity_devs) {
 122                ti->error = "Insufficient number of devices";
 123                return ERR_PTR(-EINVAL);
 124        }
 125
 126        rs = kzalloc(sizeof(*rs) + raid_devs * sizeof(rs->dev[0]), GFP_KERNEL);
 127        if (!rs) {
 128                ti->error = "Cannot allocate raid context";
 129                return ERR_PTR(-ENOMEM);
 130        }
 131
 132        mddev_init(&rs->md);
 133
 134        rs->ti = ti;
 135        rs->raid_type = raid_type;
 136        rs->md.raid_disks = raid_devs;
 137        rs->md.level = raid_type->level;
 138        rs->md.new_level = rs->md.level;
 139        rs->md.layout = raid_type->algorithm;
 140        rs->md.new_layout = rs->md.layout;
 141        rs->md.delta_disks = 0;
 142        rs->md.recovery_cp = 0;
 143
 144        for (i = 0; i < raid_devs; i++)
 145                md_rdev_init(&rs->dev[i].rdev);
 146
 147        /*
 148         * Remaining items to be initialized by further RAID params:
 149         *  rs->md.persistent
 150         *  rs->md.external
 151         *  rs->md.chunk_sectors
 152         *  rs->md.new_chunk_sectors
 153         *  rs->md.dev_sectors
 154         */
 155
 156        return rs;
 157}
 158
 159static void context_free(struct raid_set *rs)
 160{
 161        int i;
 162
 163        for (i = 0; i < rs->md.raid_disks; i++) {
 164                if (rs->dev[i].meta_dev)
 165                        dm_put_device(rs->ti, rs->dev[i].meta_dev);
 166                md_rdev_clear(&rs->dev[i].rdev);
 167                if (rs->dev[i].data_dev)
 168                        dm_put_device(rs->ti, rs->dev[i].data_dev);
 169        }
 170
 171        kfree(rs);
 172}
 173
 174/*
 175 * For every device we have two words
 176 *  <meta_dev>: meta device name or '-' if missing
 177 *  <data_dev>: data device name or '-' if missing
 178 *
 179 * The following are permitted:
 180 *    - -
 181 *    - <data_dev>
 182 *    <meta_dev> <data_dev>
 183 *
 184 * The following is not allowed:
 185 *    <meta_dev> -
 186 *
 187 * This code parses those words.  If there is a failure,
 188 * the caller must use context_free to unwind the operations.
 189 */
 190static int dev_parms(struct raid_set *rs, char **argv)
 191{
 192        int i;
 193        int rebuild = 0;
 194        int metadata_available = 0;
 195        int ret = 0;
 196
 197        for (i = 0; i < rs->md.raid_disks; i++, argv += 2) {
 198                rs->dev[i].rdev.raid_disk = i;
 199
 200                rs->dev[i].meta_dev = NULL;
 201                rs->dev[i].data_dev = NULL;
 202
 203                /*
 204                 * There are no offsets, since there is a separate device
 205                 * for data and metadata.
 206                 */
 207                rs->dev[i].rdev.data_offset = 0;
 208                rs->dev[i].rdev.mddev = &rs->md;
 209
 210                if (strcmp(argv[0], "-")) {
 211                        ret = dm_get_device(rs->ti, argv[0],
 212                                            dm_table_get_mode(rs->ti->table),
 213                                            &rs->dev[i].meta_dev);
 214                        rs->ti->error = "RAID metadata device lookup failure";
 215                        if (ret)
 216                                return ret;
 217
 218                        rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
 219                        if (!rs->dev[i].rdev.sb_page)
 220                                return -ENOMEM;
 221                }
 222
 223                if (!strcmp(argv[1], "-")) {
 224                        if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
 225                            (!rs->dev[i].rdev.recovery_offset)) {
 226                                rs->ti->error = "Drive designated for rebuild not specified";
 227                                return -EINVAL;
 228                        }
 229
 230                        rs->ti->error = "No data device supplied with metadata device";
 231                        if (rs->dev[i].meta_dev)
 232                                return -EINVAL;
 233
 234                        continue;
 235                }
 236
 237                ret = dm_get_device(rs->ti, argv[1],
 238                                    dm_table_get_mode(rs->ti->table),
 239                                    &rs->dev[i].data_dev);
 240                if (ret) {
 241                        rs->ti->error = "RAID device lookup failure";
 242                        return ret;
 243                }
 244
 245                if (rs->dev[i].meta_dev) {
 246                        metadata_available = 1;
 247                        rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
 248                }
 249                rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
 250                list_add(&rs->dev[i].rdev.same_set, &rs->md.disks);
 251                if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
 252                        rebuild++;
 253        }
 254
 255        if (metadata_available) {
 256                rs->md.external = 0;
 257                rs->md.persistent = 1;
 258                rs->md.major_version = 2;
 259        } else if (rebuild && !rs->md.recovery_cp) {
 260                /*
 261                 * Without metadata, we will not be able to tell if the array
 262                 * is in-sync or not - we must assume it is not.  Therefore,
 263                 * it is impossible to rebuild a drive.
 264                 *
 265                 * Even if there is metadata, the on-disk information may
 266                 * indicate that the array is not in-sync and it will then
 267                 * fail at that time.
 268                 *
 269                 * User could specify 'nosync' option if desperate.
 270                 */
 271                DMERR("Unable to rebuild drive while array is not in-sync");
 272                rs->ti->error = "RAID device lookup failure";
 273                return -EINVAL;
 274        }
 275
 276        return 0;
 277}
 278
 279/*
 280 * validate_region_size
 281 * @rs
 282 * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
 283 *
 284 * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
 285 * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
 286 *
 287 * Returns: 0 on success, -EINVAL on failure.
 288 */
 289static int validate_region_size(struct raid_set *rs, unsigned long region_size)
 290{
 291        unsigned long min_region_size = rs->ti->len / (1 << 21);
 292
 293        if (!region_size) {
 294                /*
 295                 * Choose a reasonable default.  All figures in sectors.
 296                 */
 297                if (min_region_size > (1 << 13)) {
 298                        DMINFO("Choosing default region size of %lu sectors",
 299                               region_size);
 300                        region_size = min_region_size;
 301                } else {
 302                        DMINFO("Choosing default region size of 4MiB");
 303                        region_size = 1 << 13; /* sectors */
 304                }
 305        } else {
 306                /*
 307                 * Validate user-supplied value.
 308                 */
 309                if (region_size > rs->ti->len) {
 310                        rs->ti->error = "Supplied region size is too large";
 311                        return -EINVAL;
 312                }
 313
 314                if (region_size < min_region_size) {
 315                        DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
 316                              region_size, min_region_size);
 317                        rs->ti->error = "Supplied region size is too small";
 318                        return -EINVAL;
 319                }
 320
 321                if (!is_power_of_2(region_size)) {
 322                        rs->ti->error = "Region size is not a power of 2";
 323                        return -EINVAL;
 324                }
 325
 326                if (region_size < rs->md.chunk_sectors) {
 327                        rs->ti->error = "Region size is smaller than the chunk size";
 328                        return -EINVAL;
 329                }
 330        }
 331
 332        /*
 333         * Convert sectors to bytes.
 334         */
 335        rs->md.bitmap_info.chunksize = (region_size << 9);
 336
 337        return 0;
 338}
 339
 340/*
 341 * Possible arguments are...
 342 *      <chunk_size> [optional_args]
 343 *
 344 * Argument definitions
 345 *    <chunk_size>                      The number of sectors per disk that
 346 *                                      will form the "stripe"
 347 *    [[no]sync]                        Force or prevent recovery of the
 348 *                                      entire array
 349 *    [rebuild <idx>]                   Rebuild the drive indicated by the index
 350 *    [daemon_sleep <ms>]               Time between bitmap daemon work to
 351 *                                      clear bits
 352 *    [min_recovery_rate <kB/sec/disk>] Throttle RAID initialization
 353 *    [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization
 354 *    [write_mostly <idx>]              Indicate a write mostly drive via index
 355 *    [max_write_behind <sectors>]      See '-write-behind=' (man mdadm)
 356 *    [stripe_cache <sectors>]          Stripe cache size for higher RAIDs
 357 *    [region_size <sectors>]           Defines granularity of bitmap
 358 *
 359 * RAID10-only options:
 360 *    [raid10_copies <# copies>]        Number of copies.  (Default: 2)
 361 *    [raid10_format <near>]            Layout algorithm.  (Default: near)
 362 */
 363static int parse_raid_params(struct raid_set *rs, char **argv,
 364                             unsigned num_raid_params)
 365{
 366        char *raid10_format = "near";
 367        unsigned raid10_copies = 2;
 368        unsigned i, rebuild_cnt = 0;
 369        unsigned long value, region_size = 0;
 370        sector_t sectors_per_dev = rs->ti->len;
 371        sector_t max_io_len;
 372        char *key;
 373
 374        /*
 375         * First, parse the in-order required arguments
 376         * "chunk_size" is the only argument of this type.
 377         */
 378        if ((strict_strtoul(argv[0], 10, &value) < 0)) {
 379                rs->ti->error = "Bad chunk size";
 380                return -EINVAL;
 381        } else if (rs->raid_type->level == 1) {
 382                if (value)
 383                        DMERR("Ignoring chunk size parameter for RAID 1");
 384                value = 0;
 385        } else if (!is_power_of_2(value)) {
 386                rs->ti->error = "Chunk size must be a power of 2";
 387                return -EINVAL;
 388        } else if (value < 8) {
 389                rs->ti->error = "Chunk size value is too small";
 390                return -EINVAL;
 391        }
 392
 393        rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
 394        argv++;
 395        num_raid_params--;
 396
 397        /*
 398         * We set each individual device as In_sync with a completed
 399         * 'recovery_offset'.  If there has been a device failure or
 400         * replacement then one of the following cases applies:
 401         *
 402         *   1) User specifies 'rebuild'.
 403         *      - Device is reset when param is read.
 404         *   2) A new device is supplied.
 405         *      - No matching superblock found, resets device.
 406         *   3) Device failure was transient and returns on reload.
 407         *      - Failure noticed, resets device for bitmap replay.
 408         *   4) Device hadn't completed recovery after previous failure.
 409         *      - Superblock is read and overrides recovery_offset.
 410         *
 411         * What is found in the superblocks of the devices is always
 412         * authoritative, unless 'rebuild' or '[no]sync' was specified.
 413         */
 414        for (i = 0; i < rs->md.raid_disks; i++) {
 415                set_bit(In_sync, &rs->dev[i].rdev.flags);
 416                rs->dev[i].rdev.recovery_offset = MaxSector;
 417        }
 418
 419        /*
 420         * Second, parse the unordered optional arguments
 421         */
 422        for (i = 0; i < num_raid_params; i++) {
 423                if (!strcasecmp(argv[i], "nosync")) {
 424                        rs->md.recovery_cp = MaxSector;
 425                        rs->print_flags |= DMPF_NOSYNC;
 426                        continue;
 427                }
 428                if (!strcasecmp(argv[i], "sync")) {
 429                        rs->md.recovery_cp = 0;
 430                        rs->print_flags |= DMPF_SYNC;
 431                        continue;
 432                }
 433
 434                /* The rest of the optional arguments come in key/value pairs */
 435                if ((i + 1) >= num_raid_params) {
 436                        rs->ti->error = "Wrong number of raid parameters given";
 437                        return -EINVAL;
 438                }
 439
 440                key = argv[i++];
 441
 442                /* Parameters that take a string value are checked here. */
 443                if (!strcasecmp(key, "raid10_format")) {
 444                        if (rs->raid_type->level != 10) {
 445                                rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
 446                                return -EINVAL;
 447                        }
 448                        if (strcmp("near", argv[i])) {
 449                                rs->ti->error = "Invalid 'raid10_format' value given";
 450                                return -EINVAL;
 451                        }
 452                        raid10_format = argv[i];
 453                        rs->print_flags |= DMPF_RAID10_FORMAT;
 454                        continue;
 455                }
 456
 457                if (strict_strtoul(argv[i], 10, &value) < 0) {
 458                        rs->ti->error = "Bad numerical argument given in raid params";
 459                        return -EINVAL;
 460                }
 461
 462                /* Parameters that take a numeric value are checked here */
 463                if (!strcasecmp(key, "rebuild")) {
 464                        rebuild_cnt++;
 465
 466                        switch (rs->raid_type->level) {
 467                        case 1:
 468                                if (rebuild_cnt >= rs->md.raid_disks) {
 469                                        rs->ti->error = "Too many rebuild devices specified";
 470                                        return -EINVAL;
 471                                }
 472                                break;
 473                        case 4:
 474                        case 5:
 475                        case 6:
 476                                if (rebuild_cnt > rs->raid_type->parity_devs) {
 477                                        rs->ti->error = "Too many rebuild devices specified for given RAID type";
 478                                        return -EINVAL;
 479                                }
 480                                break;
 481                        case 10:
 482                        default:
 483                                DMERR("The rebuild parameter is not supported for %s", rs->raid_type->name);
 484                                rs->ti->error = "Rebuild not supported for this RAID type";
 485                                return -EINVAL;
 486                        }
 487
 488                        if (value > rs->md.raid_disks) {
 489                                rs->ti->error = "Invalid rebuild index given";
 490                                return -EINVAL;
 491                        }
 492                        clear_bit(In_sync, &rs->dev[value].rdev.flags);
 493                        rs->dev[value].rdev.recovery_offset = 0;
 494                        rs->print_flags |= DMPF_REBUILD;
 495                } else if (!strcasecmp(key, "write_mostly")) {
 496                        if (rs->raid_type->level != 1) {
 497                                rs->ti->error = "write_mostly option is only valid for RAID1";
 498                                return -EINVAL;
 499                        }
 500                        if (value >= rs->md.raid_disks) {
 501                                rs->ti->error = "Invalid write_mostly drive index given";
 502                                return -EINVAL;
 503                        }
 504                        set_bit(WriteMostly, &rs->dev[value].rdev.flags);
 505                } else if (!strcasecmp(key, "max_write_behind")) {
 506                        if (rs->raid_type->level != 1) {
 507                                rs->ti->error = "max_write_behind option is only valid for RAID1";
 508                                return -EINVAL;
 509                        }
 510                        rs->print_flags |= DMPF_MAX_WRITE_BEHIND;
 511
 512                        /*
 513                         * In device-mapper, we specify things in sectors, but
 514                         * MD records this value in kB
 515                         */
 516                        value /= 2;
 517                        if (value > COUNTER_MAX) {
 518                                rs->ti->error = "Max write-behind limit out of range";
 519                                return -EINVAL;
 520                        }
 521                        rs->md.bitmap_info.max_write_behind = value;
 522                } else if (!strcasecmp(key, "daemon_sleep")) {
 523                        rs->print_flags |= DMPF_DAEMON_SLEEP;
 524                        if (!value || (value > MAX_SCHEDULE_TIMEOUT)) {
 525                                rs->ti->error = "daemon sleep period out of range";
 526                                return -EINVAL;
 527                        }
 528                        rs->md.bitmap_info.daemon_sleep = value;
 529                } else if (!strcasecmp(key, "stripe_cache")) {
 530                        rs->print_flags |= DMPF_STRIPE_CACHE;
 531
 532                        /*
 533                         * In device-mapper, we specify things in sectors, but
 534                         * MD records this value in kB
 535                         */
 536                        value /= 2;
 537
 538                        if ((rs->raid_type->level != 5) &&
 539                            (rs->raid_type->level != 6)) {
 540                                rs->ti->error = "Inappropriate argument: stripe_cache";
 541                                return -EINVAL;
 542                        }
 543                        if (raid5_set_cache_size(&rs->md, (int)value)) {
 544                                rs->ti->error = "Bad stripe_cache size";
 545                                return -EINVAL;
 546                        }
 547                } else if (!strcasecmp(key, "min_recovery_rate")) {
 548                        rs->print_flags |= DMPF_MIN_RECOVERY_RATE;
 549                        if (value > INT_MAX) {
 550                                rs->ti->error = "min_recovery_rate out of range";
 551                                return -EINVAL;
 552                        }
 553                        rs->md.sync_speed_min = (int)value;
 554                } else if (!strcasecmp(key, "max_recovery_rate")) {
 555                        rs->print_flags |= DMPF_MAX_RECOVERY_RATE;
 556                        if (value > INT_MAX) {
 557                                rs->ti->error = "max_recovery_rate out of range";
 558                                return -EINVAL;
 559                        }
 560                        rs->md.sync_speed_max = (int)value;
 561                } else if (!strcasecmp(key, "region_size")) {
 562                        rs->print_flags |= DMPF_REGION_SIZE;
 563                        region_size = value;
 564                } else if (!strcasecmp(key, "raid10_copies") &&
 565                           (rs->raid_type->level == 10)) {
 566                        if ((value < 2) || (value > 0xFF)) {
 567                                rs->ti->error = "Bad value for 'raid10_copies'";
 568                                return -EINVAL;
 569                        }
 570                        rs->print_flags |= DMPF_RAID10_COPIES;
 571                        raid10_copies = value;
 572                } else {
 573                        DMERR("Unable to parse RAID parameter: %s", key);
 574                        rs->ti->error = "Unable to parse RAID parameters";
 575                        return -EINVAL;
 576                }
 577        }
 578
 579        if (validate_region_size(rs, region_size))
 580                return -EINVAL;
 581
 582        if (rs->md.chunk_sectors)
 583                max_io_len = rs->md.chunk_sectors;
 584        else
 585                max_io_len = region_size;
 586
 587        if (dm_set_target_max_io_len(rs->ti, max_io_len))
 588                return -EINVAL;
 589
 590        if (rs->raid_type->level == 10) {
 591                if (raid10_copies > rs->md.raid_disks) {
 592                        rs->ti->error = "Not enough devices to satisfy specification";
 593                        return -EINVAL;
 594                }
 595
 596                /* (Len * #mirrors) / #devices */
 597                sectors_per_dev = rs->ti->len * raid10_copies;
 598                sector_div(sectors_per_dev, rs->md.raid_disks);
 599
 600                rs->md.layout = raid10_format_to_md_layout(raid10_format,
 601                                                           raid10_copies);
 602                rs->md.new_layout = rs->md.layout;
 603        } else if ((rs->raid_type->level > 1) &&
 604                   sector_div(sectors_per_dev,
 605                              (rs->md.raid_disks - rs->raid_type->parity_devs))) {
 606                rs->ti->error = "Target length not divisible by number of data devices";
 607                return -EINVAL;
 608        }
 609        rs->md.dev_sectors = sectors_per_dev;
 610
 611        /* Assume there are no metadata devices until the drives are parsed */
 612        rs->md.persistent = 0;
 613        rs->md.external = 1;
 614
 615        return 0;
 616}
 617
 618static void do_table_event(struct work_struct *ws)
 619{
 620        struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
 621
 622        dm_table_event(rs->ti->table);
 623}
 624
 625static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
 626{
 627        struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
 628
 629        if (rs->raid_type->level == 1)
 630                return md_raid1_congested(&rs->md, bits);
 631
 632        if (rs->raid_type->level == 10)
 633                return md_raid10_congested(&rs->md, bits);
 634
 635        return md_raid5_congested(&rs->md, bits);
 636}
 637
 638/*
 639 * This structure is never routinely used by userspace, unlike md superblocks.
 640 * Devices with this superblock should only ever be accessed via device-mapper.
 641 */
 642#define DM_RAID_MAGIC 0x64526D44
 643struct dm_raid_superblock {
 644        __le32 magic;           /* "DmRd" */
 645        __le32 features;        /* Used to indicate possible future changes */
 646
 647        __le32 num_devices;     /* Number of devices in this array. (Max 64) */
 648        __le32 array_position;  /* The position of this drive in the array */
 649
 650        __le64 events;          /* Incremented by md when superblock updated */
 651        __le64 failed_devices;  /* Bit field of devices to indicate failures */
 652
 653        /*
 654         * This offset tracks the progress of the repair or replacement of
 655         * an individual drive.
 656         */
 657        __le64 disk_recovery_offset;
 658
 659        /*
 660         * This offset tracks the progress of the initial array
 661         * synchronisation/parity calculation.
 662         */
 663        __le64 array_resync_offset;
 664
 665        /*
 666         * RAID characteristics
 667         */
 668        __le32 level;
 669        __le32 layout;
 670        __le32 stripe_sectors;
 671
 672        __u8 pad[452];          /* Round struct to 512 bytes. */
 673                                /* Always set to 0 when writing. */
 674} __packed;
 675
 676static int read_disk_sb(struct md_rdev *rdev, int size)
 677{
 678        BUG_ON(!rdev->sb_page);
 679
 680        if (rdev->sb_loaded)
 681                return 0;
 682
 683        if (!sync_page_io(rdev, 0, size, rdev->sb_page, READ, 1)) {
 684                DMERR("Failed to read superblock of device at position %d",
 685                      rdev->raid_disk);
 686                md_error(rdev->mddev, rdev);
 687                return -EINVAL;
 688        }
 689
 690        rdev->sb_loaded = 1;
 691
 692        return 0;
 693}
 694
 695static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
 696{
 697        int i;
 698        uint64_t failed_devices;
 699        struct dm_raid_superblock *sb;
 700        struct raid_set *rs = container_of(mddev, struct raid_set, md);
 701
 702        sb = page_address(rdev->sb_page);
 703        failed_devices = le64_to_cpu(sb->failed_devices);
 704
 705        for (i = 0; i < mddev->raid_disks; i++)
 706                if (!rs->dev[i].data_dev ||
 707                    test_bit(Faulty, &(rs->dev[i].rdev.flags)))
 708                        failed_devices |= (1ULL << i);
 709
 710        memset(sb, 0, sizeof(*sb));
 711
 712        sb->magic = cpu_to_le32(DM_RAID_MAGIC);
 713        sb->features = cpu_to_le32(0);  /* No features yet */
 714
 715        sb->num_devices = cpu_to_le32(mddev->raid_disks);
 716        sb->array_position = cpu_to_le32(rdev->raid_disk);
 717
 718        sb->events = cpu_to_le64(mddev->events);
 719        sb->failed_devices = cpu_to_le64(failed_devices);
 720
 721        sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
 722        sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
 723
 724        sb->level = cpu_to_le32(mddev->level);
 725        sb->layout = cpu_to_le32(mddev->layout);
 726        sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
 727}
 728
 729/*
 730 * super_load
 731 *
 732 * This function creates a superblock if one is not found on the device
 733 * and will decide which superblock to use if there's a choice.
 734 *
 735 * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
 736 */
 737static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
 738{
 739        int ret;
 740        struct dm_raid_superblock *sb;
 741        struct dm_raid_superblock *refsb;
 742        uint64_t events_sb, events_refsb;
 743
 744        rdev->sb_start = 0;
 745        rdev->sb_size = sizeof(*sb);
 746
 747        ret = read_disk_sb(rdev, rdev->sb_size);
 748        if (ret)
 749                return ret;
 750
 751        sb = page_address(rdev->sb_page);
 752
 753        /*
 754         * Two cases that we want to write new superblocks and rebuild:
 755         * 1) New device (no matching magic number)
 756         * 2) Device specified for rebuild (!In_sync w/ offset == 0)
 757         */
 758        if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
 759            (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
 760                super_sync(rdev->mddev, rdev);
 761
 762                set_bit(FirstUse, &rdev->flags);
 763
 764                /* Force writing of superblocks to disk */
 765                set_bit(MD_CHANGE_DEVS, &rdev->mddev->flags);
 766
 767                /* Any superblock is better than none, choose that if given */
 768                return refdev ? 0 : 1;
 769        }
 770
 771        if (!refdev)
 772                return 1;
 773
 774        events_sb = le64_to_cpu(sb->events);
 775
 776        refsb = page_address(refdev->sb_page);
 777        events_refsb = le64_to_cpu(refsb->events);
 778
 779        return (events_sb > events_refsb) ? 1 : 0;
 780}
 781
 782static int super_init_validation(struct mddev *mddev, struct md_rdev *rdev)
 783{
 784        int role;
 785        struct raid_set *rs = container_of(mddev, struct raid_set, md);
 786        uint64_t events_sb;
 787        uint64_t failed_devices;
 788        struct dm_raid_superblock *sb;
 789        uint32_t new_devs = 0;
 790        uint32_t rebuilds = 0;
 791        struct md_rdev *r;
 792        struct dm_raid_superblock *sb2;
 793
 794        sb = page_address(rdev->sb_page);
 795        events_sb = le64_to_cpu(sb->events);
 796        failed_devices = le64_to_cpu(sb->failed_devices);
 797
 798        /*
 799         * Initialise to 1 if this is a new superblock.
 800         */
 801        mddev->events = events_sb ? : 1;
 802
 803        /*
 804         * Reshaping is not currently allowed
 805         */
 806        if ((le32_to_cpu(sb->level) != mddev->level) ||
 807            (le32_to_cpu(sb->layout) != mddev->layout) ||
 808            (le32_to_cpu(sb->stripe_sectors) != mddev->chunk_sectors)) {
 809                DMERR("Reshaping arrays not yet supported.");
 810                return -EINVAL;
 811        }
 812
 813        /* We can only change the number of devices in RAID1 right now */
 814        if ((rs->raid_type->level != 1) &&
 815            (le32_to_cpu(sb->num_devices) != mddev->raid_disks)) {
 816                DMERR("Reshaping arrays not yet supported.");
 817                return -EINVAL;
 818        }
 819
 820        if (!(rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC)))
 821                mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
 822
 823        /*
 824         * During load, we set FirstUse if a new superblock was written.
 825         * There are two reasons we might not have a superblock:
 826         * 1) The array is brand new - in which case, all of the
 827         *    devices must have their In_sync bit set.  Also,
 828         *    recovery_cp must be 0, unless forced.
 829         * 2) This is a new device being added to an old array
 830         *    and the new device needs to be rebuilt - in which
 831         *    case the In_sync bit will /not/ be set and
 832         *    recovery_cp must be MaxSector.
 833         */
 834        rdev_for_each(r, mddev) {
 835                if (!test_bit(In_sync, &r->flags)) {
 836                        DMINFO("Device %d specified for rebuild: "
 837                               "Clearing superblock", r->raid_disk);
 838                        rebuilds++;
 839                } else if (test_bit(FirstUse, &r->flags))
 840                        new_devs++;
 841        }
 842
 843        if (!rebuilds) {
 844                if (new_devs == mddev->raid_disks) {
 845                        DMINFO("Superblocks created for new array");
 846                        set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
 847                } else if (new_devs) {
 848                        DMERR("New device injected "
 849                              "into existing array without 'rebuild' "
 850                              "parameter specified");
 851                        return -EINVAL;
 852                }
 853        } else if (new_devs) {
 854                DMERR("'rebuild' devices cannot be "
 855                      "injected into an array with other first-time devices");
 856                return -EINVAL;
 857        } else if (mddev->recovery_cp != MaxSector) {
 858                DMERR("'rebuild' specified while array is not in-sync");
 859                return -EINVAL;
 860        }
 861
 862        /*
 863         * Now we set the Faulty bit for those devices that are
 864         * recorded in the superblock as failed.
 865         */
 866        rdev_for_each(r, mddev) {
 867                if (!r->sb_page)
 868                        continue;
 869                sb2 = page_address(r->sb_page);
 870                sb2->failed_devices = 0;
 871
 872                /*
 873                 * Check for any device re-ordering.
 874                 */
 875                if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
 876                        role = le32_to_cpu(sb2->array_position);
 877                        if (role != r->raid_disk) {
 878                                if (rs->raid_type->level != 1) {
 879                                        rs->ti->error = "Cannot change device "
 880                                                "positions in RAID array";
 881                                        return -EINVAL;
 882                                }
 883                                DMINFO("RAID1 device #%d now at position #%d",
 884                                       role, r->raid_disk);
 885                        }
 886
 887                        /*
 888                         * Partial recovery is performed on
 889                         * returning failed devices.
 890                         */
 891                        if (failed_devices & (1 << role))
 892                                set_bit(Faulty, &r->flags);
 893                }
 894        }
 895
 896        return 0;
 897}
 898
 899static int super_validate(struct mddev *mddev, struct md_rdev *rdev)
 900{
 901        struct dm_raid_superblock *sb = page_address(rdev->sb_page);
 902
 903        /*
 904         * If mddev->events is not set, we know we have not yet initialized
 905         * the array.
 906         */
 907        if (!mddev->events && super_init_validation(mddev, rdev))
 908                return -EINVAL;
 909
 910        mddev->bitmap_info.offset = 4096 >> 9; /* Enable bitmap creation */
 911        rdev->mddev->bitmap_info.default_offset = 4096 >> 9;
 912        if (!test_bit(FirstUse, &rdev->flags)) {
 913                rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
 914                if (rdev->recovery_offset != MaxSector)
 915                        clear_bit(In_sync, &rdev->flags);
 916        }
 917
 918        /*
 919         * If a device comes back, set it as not In_sync and no longer faulty.
 920         */
 921        if (test_bit(Faulty, &rdev->flags)) {
 922                clear_bit(Faulty, &rdev->flags);
 923                clear_bit(In_sync, &rdev->flags);
 924                rdev->saved_raid_disk = rdev->raid_disk;
 925                rdev->recovery_offset = 0;
 926        }
 927
 928        clear_bit(FirstUse, &rdev->flags);
 929
 930        return 0;
 931}
 932
 933/*
 934 * Analyse superblocks and select the freshest.
 935 */
 936static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
 937{
 938        int ret;
 939        unsigned redundancy = 0;
 940        struct raid_dev *dev;
 941        struct md_rdev *rdev, *tmp, *freshest;
 942        struct mddev *mddev = &rs->md;
 943
 944        switch (rs->raid_type->level) {
 945        case 1:
 946                redundancy = rs->md.raid_disks - 1;
 947                break;
 948        case 4:
 949        case 5:
 950        case 6:
 951                redundancy = rs->raid_type->parity_devs;
 952                break;
 953        case 10:
 954                redundancy = raid10_md_layout_to_copies(mddev->layout) - 1;
 955                break;
 956        default:
 957                ti->error = "Unknown RAID type";
 958                return -EINVAL;
 959        }
 960
 961        freshest = NULL;
 962        rdev_for_each_safe(rdev, tmp, mddev) {
 963                if (!rdev->meta_bdev)
 964                        continue;
 965
 966                ret = super_load(rdev, freshest);
 967
 968                switch (ret) {
 969                case 1:
 970                        freshest = rdev;
 971                        break;
 972                case 0:
 973                        break;
 974                default:
 975                        dev = container_of(rdev, struct raid_dev, rdev);
 976                        if (redundancy--) {
 977                                if (dev->meta_dev)
 978                                        dm_put_device(ti, dev->meta_dev);
 979
 980                                dev->meta_dev = NULL;
 981                                rdev->meta_bdev = NULL;
 982
 983                                if (rdev->sb_page)
 984                                        put_page(rdev->sb_page);
 985
 986                                rdev->sb_page = NULL;
 987
 988                                rdev->sb_loaded = 0;
 989
 990                                /*
 991                                 * We might be able to salvage the data device
 992                                 * even though the meta device has failed.  For
 993                                 * now, we behave as though '- -' had been
 994                                 * set for this device in the table.
 995                                 */
 996                                if (dev->data_dev)
 997                                        dm_put_device(ti, dev->data_dev);
 998
 999                                dev->data_dev = NULL;
1000                                rdev->bdev = NULL;
1001
1002                                list_del(&rdev->same_set);
1003
1004                                continue;
1005                        }
1006                        ti->error = "Failed to load superblock";
1007                        return ret;
1008                }
1009        }
1010
1011        if (!freshest)
1012                return 0;
1013
1014        /*
1015         * Validation of the freshest device provides the source of
1016         * validation for the remaining devices.
1017         */
1018        ti->error = "Unable to assemble array: Invalid superblocks";
1019        if (super_validate(mddev, freshest))
1020                return -EINVAL;
1021
1022        rdev_for_each(rdev, mddev)
1023                if ((rdev != freshest) && super_validate(mddev, rdev))
1024                        return -EINVAL;
1025
1026        return 0;
1027}
1028
1029/*
1030 * Construct a RAID4/5/6 mapping:
1031 * Args:
1032 *      <raid_type> <#raid_params> <raid_params>                \
1033 *      <#raid_devs> { <meta_dev1> <dev1> .. <meta_devN> <devN> }
1034 *
1035 * <raid_params> varies by <raid_type>.  See 'parse_raid_params' for
1036 * details on possible <raid_params>.
1037 */
1038static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
1039{
1040        int ret;
1041        struct raid_type *rt;
1042        unsigned long num_raid_params, num_raid_devs;
1043        struct raid_set *rs = NULL;
1044
1045        /* Must have at least <raid_type> <#raid_params> */
1046        if (argc < 2) {
1047                ti->error = "Too few arguments";
1048                return -EINVAL;
1049        }
1050
1051        /* raid type */
1052        rt = get_raid_type(argv[0]);
1053        if (!rt) {
1054                ti->error = "Unrecognised raid_type";
1055                return -EINVAL;
1056        }
1057        argc--;
1058        argv++;
1059
1060        /* number of RAID parameters */
1061        if (strict_strtoul(argv[0], 10, &num_raid_params) < 0) {
1062                ti->error = "Cannot understand number of RAID parameters";
1063                return -EINVAL;
1064        }
1065        argc--;
1066        argv++;
1067
1068        /* Skip over RAID params for now and find out # of devices */
1069        if (num_raid_params + 1 > argc) {
1070                ti->error = "Arguments do not agree with counts given";
1071                return -EINVAL;
1072        }
1073
1074        if ((strict_strtoul(argv[num_raid_params], 10, &num_raid_devs) < 0) ||
1075            (num_raid_devs >= INT_MAX)) {
1076                ti->error = "Cannot understand number of raid devices";
1077                return -EINVAL;
1078        }
1079
1080        rs = context_alloc(ti, rt, (unsigned)num_raid_devs);
1081        if (IS_ERR(rs))
1082                return PTR_ERR(rs);
1083
1084        ret = parse_raid_params(rs, argv, (unsigned)num_raid_params);
1085        if (ret)
1086                goto bad;
1087
1088        ret = -EINVAL;
1089
1090        argc -= num_raid_params + 1; /* +1: we already have num_raid_devs */
1091        argv += num_raid_params + 1;
1092
1093        if (argc != (num_raid_devs * 2)) {
1094                ti->error = "Supplied RAID devices does not match the count given";
1095                goto bad;
1096        }
1097
1098        ret = dev_parms(rs, argv);
1099        if (ret)
1100                goto bad;
1101
1102        rs->md.sync_super = super_sync;
1103        ret = analyse_superblocks(ti, rs);
1104        if (ret)
1105                goto bad;
1106
1107        INIT_WORK(&rs->md.event_work, do_table_event);
1108        ti->private = rs;
1109        ti->num_flush_requests = 1;
1110
1111        mutex_lock(&rs->md.reconfig_mutex);
1112        ret = md_run(&rs->md);
1113        rs->md.in_sync = 0; /* Assume already marked dirty */
1114        mutex_unlock(&rs->md.reconfig_mutex);
1115
1116        if (ret) {
1117                ti->error = "Fail to run raid array";
1118                goto bad;
1119        }
1120
1121        if (ti->len != rs->md.array_sectors) {
1122                ti->error = "Array size does not match requested target length";
1123                ret = -EINVAL;
1124                goto size_mismatch;
1125        }
1126        rs->callbacks.congested_fn = raid_is_congested;
1127        dm_table_add_target_callbacks(ti->table, &rs->callbacks);
1128
1129        mddev_suspend(&rs->md);
1130        return 0;
1131
1132size_mismatch:
1133        md_stop(&rs->md);
1134bad:
1135        context_free(rs);
1136
1137        return ret;
1138}
1139
1140static void raid_dtr(struct dm_target *ti)
1141{
1142        struct raid_set *rs = ti->private;
1143
1144        list_del_init(&rs->callbacks.list);
1145        md_stop(&rs->md);
1146        context_free(rs);
1147}
1148
1149static int raid_map(struct dm_target *ti, struct bio *bio, union map_info *map_context)
1150{
1151        struct raid_set *rs = ti->private;
1152        struct mddev *mddev = &rs->md;
1153
1154        mddev->pers->make_request(mddev, bio);
1155
1156        return DM_MAPIO_SUBMITTED;
1157}
1158
1159static int raid_status(struct dm_target *ti, status_type_t type,
1160                       unsigned status_flags, char *result, unsigned maxlen)
1161{
1162        struct raid_set *rs = ti->private;
1163        unsigned raid_param_cnt = 1; /* at least 1 for chunksize */
1164        unsigned sz = 0;
1165        int i, array_in_sync = 0;
1166        sector_t sync;
1167
1168        switch (type) {
1169        case STATUSTYPE_INFO:
1170                DMEMIT("%s %d ", rs->raid_type->name, rs->md.raid_disks);
1171
1172                if (test_bit(MD_RECOVERY_RUNNING, &rs->md.recovery))
1173                        sync = rs->md.curr_resync_completed;
1174                else
1175                        sync = rs->md.recovery_cp;
1176
1177                if (sync >= rs->md.resync_max_sectors) {
1178                        array_in_sync = 1;
1179                        sync = rs->md.resync_max_sectors;
1180                } else {
1181                        /*
1182                         * The array may be doing an initial sync, or it may
1183                         * be rebuilding individual components.  If all the
1184                         * devices are In_sync, then it is the array that is
1185                         * being initialized.
1186                         */
1187                        for (i = 0; i < rs->md.raid_disks; i++)
1188                                if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
1189                                        array_in_sync = 1;
1190                }
1191                /*
1192                 * Status characters:
1193                 *  'D' = Dead/Failed device
1194                 *  'a' = Alive but not in-sync
1195                 *  'A' = Alive and in-sync
1196                 */
1197                for (i = 0; i < rs->md.raid_disks; i++) {
1198                        if (test_bit(Faulty, &rs->dev[i].rdev.flags))
1199                                DMEMIT("D");
1200                        else if (!array_in_sync ||
1201                                 !test_bit(In_sync, &rs->dev[i].rdev.flags))
1202                                DMEMIT("a");
1203                        else
1204                                DMEMIT("A");
1205                }
1206
1207                /*
1208                 * In-sync ratio:
1209                 *  The in-sync ratio shows the progress of:
1210                 *   - Initializing the array
1211                 *   - Rebuilding a subset of devices of the array
1212                 *  The user can distinguish between the two by referring
1213                 *  to the status characters.
1214                 */
1215                DMEMIT(" %llu/%llu",
1216                       (unsigned long long) sync,
1217                       (unsigned long long) rs->md.resync_max_sectors);
1218
1219                break;
1220        case STATUSTYPE_TABLE:
1221                /* The string you would use to construct this array */
1222                for (i = 0; i < rs->md.raid_disks; i++) {
1223                        if ((rs->print_flags & DMPF_REBUILD) &&
1224                            rs->dev[i].data_dev &&
1225                            !test_bit(In_sync, &rs->dev[i].rdev.flags))
1226                                raid_param_cnt += 2; /* for rebuilds */
1227                        if (rs->dev[i].data_dev &&
1228                            test_bit(WriteMostly, &rs->dev[i].rdev.flags))
1229                                raid_param_cnt += 2;
1230                }
1231
1232                raid_param_cnt += (hweight32(rs->print_flags & ~DMPF_REBUILD) * 2);
1233                if (rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC))
1234                        raid_param_cnt--;
1235
1236                DMEMIT("%s %u %u", rs->raid_type->name,
1237                       raid_param_cnt, rs->md.chunk_sectors);
1238
1239                if ((rs->print_flags & DMPF_SYNC) &&
1240                    (rs->md.recovery_cp == MaxSector))
1241                        DMEMIT(" sync");
1242                if (rs->print_flags & DMPF_NOSYNC)
1243                        DMEMIT(" nosync");
1244
1245                for (i = 0; i < rs->md.raid_disks; i++)
1246                        if ((rs->print_flags & DMPF_REBUILD) &&
1247                            rs->dev[i].data_dev &&
1248                            !test_bit(In_sync, &rs->dev[i].rdev.flags))
1249                                DMEMIT(" rebuild %u", i);
1250
1251                if (rs->print_flags & DMPF_DAEMON_SLEEP)
1252                        DMEMIT(" daemon_sleep %lu",
1253                               rs->md.bitmap_info.daemon_sleep);
1254
1255                if (rs->print_flags & DMPF_MIN_RECOVERY_RATE)
1256                        DMEMIT(" min_recovery_rate %d", rs->md.sync_speed_min);
1257
1258                if (rs->print_flags & DMPF_MAX_RECOVERY_RATE)
1259                        DMEMIT(" max_recovery_rate %d", rs->md.sync_speed_max);
1260
1261                for (i = 0; i < rs->md.raid_disks; i++)
1262                        if (rs->dev[i].data_dev &&
1263                            test_bit(WriteMostly, &rs->dev[i].rdev.flags))
1264                                DMEMIT(" write_mostly %u", i);
1265
1266                if (rs->print_flags & DMPF_MAX_WRITE_BEHIND)
1267                        DMEMIT(" max_write_behind %lu",
1268                               rs->md.bitmap_info.max_write_behind);
1269
1270                if (rs->print_flags & DMPF_STRIPE_CACHE) {
1271                        struct r5conf *conf = rs->md.private;
1272
1273                        /* convert from kiB to sectors */
1274                        DMEMIT(" stripe_cache %d",
1275                               conf ? conf->max_nr_stripes * 2 : 0);
1276                }
1277
1278                if (rs->print_flags & DMPF_REGION_SIZE)
1279                        DMEMIT(" region_size %lu",
1280                               rs->md.bitmap_info.chunksize >> 9);
1281
1282                if (rs->print_flags & DMPF_RAID10_COPIES)
1283                        DMEMIT(" raid10_copies %u",
1284                               raid10_md_layout_to_copies(rs->md.layout));
1285
1286                if (rs->print_flags & DMPF_RAID10_FORMAT)
1287                        DMEMIT(" raid10_format near");
1288
1289                DMEMIT(" %d", rs->md.raid_disks);
1290                for (i = 0; i < rs->md.raid_disks; i++) {
1291                        if (rs->dev[i].meta_dev)
1292                                DMEMIT(" %s", rs->dev[i].meta_dev->name);
1293                        else
1294                                DMEMIT(" -");
1295
1296                        if (rs->dev[i].data_dev)
1297                                DMEMIT(" %s", rs->dev[i].data_dev->name);
1298                        else
1299                                DMEMIT(" -");
1300                }
1301        }
1302
1303        return 0;
1304}
1305
1306static int raid_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
1307{
1308        struct raid_set *rs = ti->private;
1309        unsigned i;
1310        int ret = 0;
1311
1312        for (i = 0; !ret && i < rs->md.raid_disks; i++)
1313                if (rs->dev[i].data_dev)
1314                        ret = fn(ti,
1315                                 rs->dev[i].data_dev,
1316                                 0, /* No offset on data devs */
1317                                 rs->md.dev_sectors,
1318                                 data);
1319
1320        return ret;
1321}
1322
1323static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
1324{
1325        struct raid_set *rs = ti->private;
1326        unsigned chunk_size = rs->md.chunk_sectors << 9;
1327        struct r5conf *conf = rs->md.private;
1328
1329        blk_limits_io_min(limits, chunk_size);
1330        blk_limits_io_opt(limits, chunk_size * (conf->raid_disks - conf->max_degraded));
1331}
1332
1333static void raid_presuspend(struct dm_target *ti)
1334{
1335        struct raid_set *rs = ti->private;
1336
1337        md_stop_writes(&rs->md);
1338}
1339
1340static void raid_postsuspend(struct dm_target *ti)
1341{
1342        struct raid_set *rs = ti->private;
1343
1344        mddev_suspend(&rs->md);
1345}
1346
1347static void raid_resume(struct dm_target *ti)
1348{
1349        struct raid_set *rs = ti->private;
1350
1351        set_bit(MD_CHANGE_DEVS, &rs->md.flags);
1352        if (!rs->bitmap_loaded) {
1353                bitmap_load(&rs->md);
1354                rs->bitmap_loaded = 1;
1355        }
1356
1357        clear_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
1358        mddev_resume(&rs->md);
1359}
1360
1361static struct target_type raid_target = {
1362        .name = "raid",
1363        .version = {1, 3, 0},
1364        .module = THIS_MODULE,
1365        .ctr = raid_ctr,
1366        .dtr = raid_dtr,
1367        .map = raid_map,
1368        .status = raid_status,
1369        .iterate_devices = raid_iterate_devices,
1370        .io_hints = raid_io_hints,
1371        .presuspend = raid_presuspend,
1372        .postsuspend = raid_postsuspend,
1373        .resume = raid_resume,
1374};
1375
1376static int __init dm_raid_init(void)
1377{
1378        return dm_register_target(&raid_target);
1379}
1380
1381static void __exit dm_raid_exit(void)
1382{
1383        dm_unregister_target(&raid_target);
1384}
1385
1386module_init(dm_raid_init);
1387module_exit(dm_raid_exit);
1388
1389MODULE_DESCRIPTION(DM_NAME " raid4/5/6 target");
1390MODULE_ALIAS("dm-raid1");
1391MODULE_ALIAS("dm-raid10");
1392MODULE_ALIAS("dm-raid4");
1393MODULE_ALIAS("dm-raid5");
1394MODULE_ALIAS("dm-raid6");
1395MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
1396MODULE_LICENSE("GPL");
1397
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