drivers/md/dm-raid.c

   1 /*
   2  * Copyright (C) 2010-2011 Neil Brown
   3  * Copyright (C) 2010-2016 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 #define MAX_RAID_DEVICES        253 /* md-raid kernel limit */
  21
  22 static bool devices_handle_discard_safely = false;
  23
  24 /*
  25  * The following flags are used by dm-raid.c to set up the array state.
  26  * They must be cleared before md_run is called.
  27  */
  28 #define FirstUse 10             /* rdev flag */
  29
  30 struct raid_dev {
  31         /*
  32          * Two DM devices, one to hold metadata and one to hold the
  33          * actual data/parity.  The reason for this is to not confuse
  34          * ti->len and give more flexibility in altering size and
  35          * characteristics.
  36          *
  37          * While it is possible for this device to be associated
  38          * with a different physical device than the data_dev, it
  39          * is intended for it to be the same.
  40          *    |--------- Physical Device ---------|
  41          *    |- meta_dev -|------ data_dev ------|
  42          */
  43         struct dm_dev *meta_dev;
  44         struct dm_dev *data_dev;
  45         struct md_rdev rdev;
  46 };
  47
  48 /*
  49  * Flags for rs->ctr_flags field.
  50  *
  51  * 1 = no flag value
  52  * 2 = flag with value
  53  */
  54 #define CTR_FLAG_SYNC              0x1   /* 1 */ /* Not with raid0! */
  55 #define CTR_FLAG_NOSYNC            0x2   /* 1 */ /* Not with raid0! */
  56 #define CTR_FLAG_REBUILD           0x4   /* 2 */ /* Not with raid0! */
  57 #define CTR_FLAG_DAEMON_SLEEP      0x8   /* 2 */ /* Not with raid0! */
  58 #define CTR_FLAG_MIN_RECOVERY_RATE 0x10  /* 2 */ /* Not with raid0! */
  59 #define CTR_FLAG_MAX_RECOVERY_RATE 0x20  /* 2 */ /* Not with raid0! */
  60 #define CTR_FLAG_MAX_WRITE_BEHIND  0x40  /* 2 */ /* Only with raid1! */
  61 #define CTR_FLAG_WRITE_MOSTLY      0x80  /* 2 */ /* Only with raid1! */
  62 #define CTR_FLAG_STRIPE_CACHE      0x100 /* 2 */ /* Only with raid4/5/6! */
  63 #define CTR_FLAG_REGION_SIZE       0x200 /* 2 */ /* Not with raid0! */
  64 #define CTR_FLAG_RAID10_COPIES     0x400 /* 2 */ /* Only with raid10 */
  65 #define CTR_FLAG_RAID10_FORMAT     0x800 /* 2 */ /* Only with raid10 */
  66 /* New for v1.9.0 */
  67 #define CTR_FLAG_DELTA_DISKS          0x1000 /* 2 */ /* Only with reshapable raid4/5/6/10! */
  68 #define CTR_FLAG_DATA_OFFSET          0x2000 /* 2 */ /* Only with reshapable raid4/5/6/10! */
  69 #define CTR_FLAG_RAID10_USE_NEAR_SETS 0x4000 /* 2 */ /* Only with raid10! */
  70
  71 /*
  72  * Definitions of various constructor flags to
  73  * be used in checks of valid / invalid flags
  74  * per raid level.
  75  */
  76 /* Define all any sync flags */
  77 #define CTR_FLAGS_ANY_SYNC              (CTR_FLAG_SYNC | CTR_FLAG_NOSYNC)
  78
  79 /* Define flags for options without argument (e.g. 'nosync') */
  80 #define CTR_FLAG_OPTIONS_NO_ARGS        (CTR_FLAGS_ANY_SYNC | \
  81                                          CTR_FLAG_RAID10_USE_NEAR_SETS)
  82
  83 /* Define flags for options with one argument (e.g. 'delta_disks +2') */
  84 #define CTR_FLAG_OPTIONS_ONE_ARG (CTR_FLAG_REBUILD | \
  85                                   CTR_FLAG_WRITE_MOSTLY | \
  86                                   CTR_FLAG_DAEMON_SLEEP | \
  87                                   CTR_FLAG_MIN_RECOVERY_RATE | \
  88                                   CTR_FLAG_MAX_RECOVERY_RATE | \
  89                                   CTR_FLAG_MAX_WRITE_BEHIND | \
  90                                   CTR_FLAG_STRIPE_CACHE | \
  91                                   CTR_FLAG_REGION_SIZE | \
  92                                   CTR_FLAG_RAID10_COPIES | \
  93                                   CTR_FLAG_RAID10_FORMAT | \
  94                                   CTR_FLAG_DELTA_DISKS | \
  95                                   CTR_FLAG_DATA_OFFSET)
  96
  97 /* All ctr optional arguments */
  98 #define ALL_CTR_FLAGS           (CTR_FLAG_OPTIONS_NO_ARGS | \
  99                                  CTR_FLAG_OPTIONS_ONE_ARG)
 100
 101 /* Invalid options definitions per raid level... */
 102
 103 /* "raid0" does not accept any options */
 104 #define RAID0_INVALID_FLAGS ALL_CTR_FLAGS
 105
 106 /* "raid1" does not accept stripe cache or any raid10 options */
 107 #define RAID1_INVALID_FLAGS     (CTR_FLAG_STRIPE_CACHE | \
 108                                  CTR_FLAG_RAID10_COPIES | \
 109                                  CTR_FLAG_RAID10_FORMAT | \
 110                                  CTR_FLAG_DELTA_DISKS | \
 111                                  CTR_FLAG_DATA_OFFSET)
 112
 113 /* "raid10" does not accept any raid1 or stripe cache options */
 114 #define RAID10_INVALID_FLAGS    (CTR_FLAG_WRITE_MOSTLY | \
 115                                  CTR_FLAG_MAX_WRITE_BEHIND | \
 116                                  CTR_FLAG_STRIPE_CACHE)
 117 /*
 118  * "raid4/5/6" do not accept any raid1 or raid10 specific options
 119  *
 120  * "raid6" does not accept "nosync", because it is not guaranteed
 121  * that both parity and q-syndrome are being written properly with
 122  * any writes
 123  */
 124 #define RAID45_INVALID_FLAGS    (CTR_FLAG_WRITE_MOSTLY | \
 125                                  CTR_FLAG_MAX_WRITE_BEHIND | \
 126                                  CTR_FLAG_RAID10_FORMAT | \
 127                                  CTR_FLAG_RAID10_COPIES | \
 128                                  CTR_FLAG_RAID10_USE_NEAR_SETS)
 129 #define RAID6_INVALID_FLAGS     (CTR_FLAG_NOSYNC | RAID45_INVALID_FLAGS)
 130 /* ...invalid options definitions per raid level */
 131
 132 /*
 133  * Flags for rs->runtime_flags field
 134  * (RT_FLAG prefix meaning "runtime flag")
 135  *
 136  * These are all internal and used to define runtime state,
 137  * e.g. to prevent another resume from preresume processing
 138  * the raid set all over again.
 139  */
 140 #define RT_FLAG_RS_PRERESUMED           0x1
 141 #define RT_FLAG_RS_RESUMED              0x2
 142 #define RT_FLAG_RS_BITMAP_LOADED        0x4
 143 #define RT_FLAG_UPDATE_SBS              0x8
 144
 145 /* Array elements of 64 bit needed for rebuild/write_mostly bits */
 146 #define DISKS_ARRAY_ELEMS ((MAX_RAID_DEVICES + (sizeof(uint64_t) * 8 - 1)) / sizeof(uint64_t) / 8)
 147
 148 /*
 149  * raid set level, layout and chunk sectors backup/restore
 150  */
 151 struct rs_layout {
 152         int new_level;
 153         int new_layout;
 154         int new_chunk_sectors;
 155 };
 156
 157 struct raid_set {
 158         struct dm_target *ti;
 159
 160         uint32_t bitmap_loaded;
 161         uint32_t ctr_flags;
 162         uint32_t runtime_flags;
 163
 164         uint64_t rebuild_disks[DISKS_ARRAY_ELEMS];
 165
 166         int raid_disks;
 167         int delta_disks;
 168         int data_offset;
 169         int raid10_copies;
 170
 171         struct mddev md;
 172         struct raid_type *raid_type;
 173         struct dm_target_callbacks callbacks;
 174         struct rs_layout rs_layout;
 175
 176         struct raid_dev dev[0];
 177 };
 178
 179 /* Backup/restore raid set configuration helpers */
 180 static void _rs_config_backup(struct raid_set *rs, struct rs_layout *l)
 181 {
 182         struct mddev *mddev = &rs->md;
 183
 184         l->new_level = mddev->new_level;
 185         l->new_layout = mddev->new_layout;
 186         l->new_chunk_sectors = mddev->new_chunk_sectors;
 187 }
 188
 189 static void rs_config_backup(struct raid_set *rs)
 190 {
 191         return _rs_config_backup(rs, &rs->rs_layout);
 192 }
 193
 194 static void _rs_config_restore(struct raid_set *rs, struct rs_layout *l)
 195 {
 196         struct mddev *mddev = &rs->md;
 197
 198         mddev->new_level = l->new_level;
 199         mddev->new_layout = l->new_layout;
 200         mddev->new_chunk_sectors = l->new_chunk_sectors;
 201 }
 202
 203 static void rs_config_restore(struct raid_set *rs)
 204 {
 205         return _rs_config_restore(rs, &rs->rs_layout);
 206 }
 207 /* END: backup/restore raid set configuration helpers */
 208
 209 /* raid10 algorithms (i.e. formats) */
 210 #define ALGORITHM_RAID10_DEFAULT        0
 211 #define ALGORITHM_RAID10_NEAR           1
 212 #define ALGORITHM_RAID10_OFFSET         2
 213 #define ALGORITHM_RAID10_FAR            3
 214
 215 /* Supported raid types and properties. */
 216 static struct raid_type {
 217         const char *name;               /* RAID algorithm. */
 218         const char *descr;              /* Descriptor text for logging. */
 219         const unsigned parity_devs;     /* # of parity devices. */
 220         const unsigned minimal_devs;    /* minimal # of devices in set. */
 221         const unsigned level;           /* RAID level. */
 222         const unsigned algorithm;       /* RAID algorithm. */
 223 } raid_types[] = {
 224         {"raid0",         "raid0 (striping)",                       0, 2, 0,  0 /* NONE */},
 225         {"raid1",         "raid1 (mirroring)",                      0, 2, 1,  0 /* NONE */},
 226         {"raid10_far",    "raid10 far (striped mirrors)",           0, 2, 10, ALGORITHM_RAID10_FAR},
 227         {"raid10_offset", "raid10 offset (striped mirrors)",        0, 2, 10, ALGORITHM_RAID10_OFFSET},
 228         {"raid10_near",   "raid10 near (striped mirrors)",          0, 2, 10, ALGORITHM_RAID10_NEAR},
 229         {"raid10",        "raid10 (striped mirrors)",               0, 2, 10, ALGORITHM_RAID10_DEFAULT},
 230         {"raid4",         "raid4 (dedicated last parity disk)",     1, 2, 4,  ALGORITHM_PARITY_N}, /* raid4 layout = raid5_n */
 231         {"raid5_n",       "raid5 (dedicated last parity disk)",     1, 2, 5,  ALGORITHM_PARITY_N},
 232         {"raid5_ls",      "raid5 (left symmetric)",                 1, 2, 5,  ALGORITHM_LEFT_SYMMETRIC},
 233         {"raid5_rs",      "raid5 (right symmetric)",                1, 2, 5,  ALGORITHM_RIGHT_SYMMETRIC},
 234         {"raid5_la",      "raid5 (left asymmetric)",                1, 2, 5,  ALGORITHM_LEFT_ASYMMETRIC},
 235         {"raid5_ra",      "raid5 (right asymmetric)",               1, 2, 5,  ALGORITHM_RIGHT_ASYMMETRIC},
 236         {"raid6_zr",      "raid6 (zero restart)",                   2, 4, 6,  ALGORITHM_ROTATING_ZERO_RESTART},
 237         {"raid6_nr",      "raid6 (N restart)",                      2, 4, 6,  ALGORITHM_ROTATING_N_RESTART},
 238         {"raid6_nc",      "raid6 (N continue)",                     2, 4, 6,  ALGORITHM_ROTATING_N_CONTINUE},
 239         {"raid6_n_6",     "raid6 (dedicated parity/Q n/6)",         2, 4, 6,  ALGORITHM_PARITY_N_6},
 240         {"raid6_ls_6",    "raid6 (left symmetric dedicated Q 6)",   2, 4, 6,  ALGORITHM_LEFT_SYMMETRIC_6},
 241         {"raid6_rs_6",    "raid6 (right symmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_RIGHT_SYMMETRIC_6},
 242         {"raid6_la_6",    "raid6 (left asymmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_LEFT_ASYMMETRIC_6},
 243         {"raid6_ra_6",    "raid6 (right asymmetric dedicated Q 6)", 2, 4, 6,  ALGORITHM_RIGHT_ASYMMETRIC_6}
 244 };
 245
 246 /* True, if @v is in inclusive range [@min, @max] */
 247 static bool _in_range(long v, long min, long max)
 248 {
 249         return v >= min && v <= max;
 250 }
 251
 252 /* ctr flag bit manipulation... */
 253 /* Set single @flag in @flags */
 254 static void _set_flag(uint32_t flag, uint32_t *flags)
 255 {
 256         WARN_ON_ONCE(hweight32(flag) != 1);
 257         *flags |= flag;
 258 }
 259
 260 /* Clear single @flag in @flags */
 261 static void _clear_flag(uint32_t flag, uint32_t *flags)
 262 {
 263         WARN_ON_ONCE(hweight32(flag) != 1);
 264         *flags &= ~flag;
 265 }
 266
 267 /* Test single @flag in @flags */
 268 static bool _test_flag(uint32_t flag, uint32_t flags)
 269 {
 270         WARN_ON_ONCE(hweight32(flag) != 1);
 271         return (flag & flags) ? true : false;
 272 }
 273
 274 /* Test multiple @flags in @all_flags */
 275 static bool _test_flags(uint32_t flags, uint32_t all_flags)
 276 {
 277         return (flags & all_flags) ? true : false;
 278 }
 279
 280 /* Clear (multiple) @flags in @all_flags */
 281 static void _clear_flags(uint32_t flags, uint32_t *all_flags)
 282 {
 283         *all_flags &= ~flags;
 284 }
 285
 286 /* Return true if single @flag is set in @*flags, else set it and return false */
 287 static bool _test_and_set_flag(uint32_t flag, uint32_t *flags)
 288 {
 289         if (_test_flag(flag, *flags))
 290                 return true;
 291
 292         _set_flag(flag, flags);
 293         return false;
 294 }
 295
 296 /* Return true if single @flag is set in @*flags and clear it, else return false */
 297 static bool _test_and_clear_flag(uint32_t flag, uint32_t *flags)
 298 {
 299         if (_test_flag(flag, *flags)) {
 300                 _clear_flag(flag, flags);
 301                 return true;
 302         }
 303
 304         return false;
 305 }
 306 /* ...ctr and runtime flag bit manipulation */
 307
 308 /* All table line arguments are defined here */
 309 static struct arg_name_flag {
 310         const uint32_t flag;
 311         const char *name;
 312 } _arg_name_flags[] = {
 313         { CTR_FLAG_SYNC, "sync"},
 314         { CTR_FLAG_NOSYNC, "nosync"},
 315         { CTR_FLAG_REBUILD, "rebuild"},
 316         { CTR_FLAG_DAEMON_SLEEP, "daemon_sleep"},
 317         { CTR_FLAG_MIN_RECOVERY_RATE, "min_recovery_rate"},
 318         { CTR_FLAG_MAX_RECOVERY_RATE, "max_recovery_rate"},
 319         { CTR_FLAG_MAX_WRITE_BEHIND, "max_write_behind"},
 320         { CTR_FLAG_WRITE_MOSTLY, "writemostly"},
 321         { CTR_FLAG_STRIPE_CACHE, "stripe_cache"},
 322         { CTR_FLAG_REGION_SIZE, "region_size"},
 323         { CTR_FLAG_RAID10_COPIES, "raid10_copies"},
 324         { CTR_FLAG_RAID10_FORMAT, "raid10_format"},
 325         { CTR_FLAG_DATA_OFFSET, "data_offset"},
 326         { CTR_FLAG_DELTA_DISKS, "delta_disks"},
 327         { CTR_FLAG_RAID10_USE_NEAR_SETS, "raid10_use_near_sets"},
 328 };
 329
 330 /* Return argument name string for given @flag */
 331 static const char *dm_raid_arg_name_by_flag(const uint32_t flag)
 332 {
 333         if (hweight32(flag) == 1) {
 334                 struct arg_name_flag *anf = _arg_name_flags + ARRAY_SIZE(_arg_name_flags);
 335
 336                 while (anf-- > _arg_name_flags)
 337                         if (_test_flag(flag, anf->flag))
 338                                 return anf->name;
 339
 340         } else
 341                 DMERR("%s called with more than one flag!", __func__);
 342
 343         return NULL;
 344 }
 345
 346 /*
 347  * bool helpers to test for various raid levels of a raid set,
 348  * is. it's level as reported by the superblock rather than
 349  * the requested raid_type passed to the constructor.
 350  */
 351 /* Return true, if raid set in @rs is raid0 */
 352 static bool rs_is_raid0(struct raid_set *rs)
 353 {
 354         return !rs->md.level;
 355 }
 356
 357 /* Return true, if raid set in @rs is raid10 */
 358 static bool rs_is_raid10(struct raid_set *rs)
 359 {
 360         return rs->md.level == 10;
 361 }
 362
 363 /*
 364  * bool helpers to test for various raid levels of a raid type
 365  */
 366
 367 /* Return true, if raid type in @rt is raid0 */
 368 static bool rt_is_raid0(struct raid_type *rt)
 369 {
 370         return !rt->level;
 371 }
 372
 373 /* Return true, if raid type in @rt is raid1 */
 374 static bool rt_is_raid1(struct raid_type *rt)
 375 {
 376         return rt->level == 1;
 377 }
 378
 379 /* Return true, if raid type in @rt is raid10 */
 380 static bool rt_is_raid10(struct raid_type *rt)
 381 {
 382         return rt->level == 10;
 383 }
 384
 385 /* Return true, if raid type in @rt is raid4/5 */
 386 static bool rt_is_raid45(struct raid_type *rt)
 387 {
 388         return _in_range(rt->level, 4, 5);
 389 }
 390
 391 /* Return true, if raid type in @rt is raid6 */
 392 static bool rt_is_raid6(struct raid_type *rt)
 393 {
 394         return rt->level == 6;
 395 }
 396
 397 /* Return true, if raid type in @rt is raid4/5/6 */
 398 static bool rt_is_raid456(struct raid_type *rt)
 399 {
 400         return _in_range(rt->level, 4, 6);
 401 }
 402 /* END: raid level bools */
 403
 404 /* Return invalid ctr flags for the raid level of @rs */
 405 static uint32_t _invalid_flags(struct raid_set *rs)
 406 {
 407         if (rt_is_raid0(rs->raid_type))
 408                 return RAID0_INVALID_FLAGS;
 409         else if (rt_is_raid1(rs->raid_type))
 410                 return RAID1_INVALID_FLAGS;
 411         else if (rt_is_raid10(rs->raid_type))
 412                 return RAID10_INVALID_FLAGS;
 413         else if (rt_is_raid45(rs->raid_type))
 414                 return RAID45_INVALID_FLAGS;
 415         else if (rt_is_raid6(rs->raid_type))
 416                 return RAID6_INVALID_FLAGS;
 417
 418         return ~0;
 419 }
 420
 421 /*
 422  * Check for any invalid flags set on @rs defined by bitset @invalid_flags
 423  *
 424  * Has to be called after parsing of the ctr flags!
 425  */
 426 static int rs_check_for_invalid_flags(struct raid_set *rs)
 427 {
 428         if (_test_flags(rs->ctr_flags, _invalid_flags(rs))) {
 429                 rs->ti->error = "Invalid flag combined";
 430                 return -EINVAL;
 431         }
 432
 433         return 0;
 434 }
 435
 436
 437 /* MD raid10 bit definitions and helpers */
 438 #define RAID10_OFFSET                   (1 << 16) /* stripes with data copies area adjacent on devices */
 439 #define RAID10_BROCKEN_USE_FAR_SETS     (1 << 17) /* Broken in raid10.c: use sets instead of whole stripe rotation */
 440 #define RAID10_USE_FAR_SETS             (1 << 18) /* Use sets instead of whole stripe rotation */
 441 #define RAID10_FAR_COPIES_SHIFT         8         /* raid10 # far copies shift (2nd byte of layout) */
 442
 443 /* Return md raid10 near copies for @layout */
 444 static unsigned int _raid10_near_copies(int layout)
 445 {
 446         return layout & 0xFF;
 447 }
 448
 449 /* Return md raid10 far copies for @layout */
 450 static unsigned int _raid10_far_copies(int layout)
 451 {
 452         return _raid10_near_copies(layout >> RAID10_FAR_COPIES_SHIFT);
 453 }
 454
 455 /* Return true if md raid10 offset for @layout */
 456 static unsigned int _is_raid10_offset(int layout)
 457 {
 458         return layout & RAID10_OFFSET;
 459 }
 460
 461 /* Return true if md raid10 near for @layout */
 462 static unsigned int _is_raid10_near(int layout)
 463 {
 464         return !_is_raid10_offset(layout) && _raid10_near_copies(layout) > 1;
 465 }
 466
 467 /* Return true if md raid10 far for @layout */
 468 static unsigned int _is_raid10_far(int layout)
 469 {
 470         return !_is_raid10_offset(layout) && _raid10_far_copies(layout) > 1;
 471 }
 472
 473 /* Return md raid10 layout string for @layout */
 474 static const char *raid10_md_layout_to_format(int layout)
 475 {
 476         /*
 477          * Bit 16 stands for "offset"
 478          * (i.e. adjacent stripes hold copies)
 479          *
 480          * Refer to MD's raid10.c for details
 481          */
 482         if (_is_raid10_offset(layout))
 483                 return "offset";
 484
 485         if (_raid10_near_copies(layout) > 1)
 486                 return "near";
 487
 488         WARN_ON(_raid10_far_copies(layout) < 2);
 489
 490         return "far";
 491 }
 492
 493 /* Return md raid10 algorithm for @name */
 494 static const int raid10_name_to_format(const char *name)
 495 {
 496         if (!strcasecmp(name, "near"))
 497                 return ALGORITHM_RAID10_NEAR;
 498         else if (!strcasecmp(name, "offset"))
 499                 return ALGORITHM_RAID10_OFFSET;
 500         else if (!strcasecmp(name, "far"))
 501                 return ALGORITHM_RAID10_FAR;
 502
 503         return -EINVAL;
 504 }
 505
 506
 507 /* Return md raid10 copies for @layout */
 508 static unsigned int raid10_md_layout_to_copies(int layout)
 509 {
 510         return _raid10_near_copies(layout) > 1 ?
 511                _raid10_near_copies(layout) : _raid10_far_copies(layout);
 512 }
 513
 514 /* Return md raid10 format id for @format string */
 515 static int raid10_format_to_md_layout(struct raid_set *rs,
 516                                       unsigned int algorithm,
 517                                       unsigned int copies)
 518 {
 519         unsigned int n = 1, f = 1, r = 0;
 520
 521         /*
 522          * MD resilienece flaw:
 523          *
 524          * enabling use_far_sets for far/offset formats causes copies
 525          * to be colocated on the same devs together with their origins!
 526          *
 527          * -> disable it for now in the definition above
 528          */
 529         if (algorithm == ALGORITHM_RAID10_DEFAULT ||
 530             algorithm == ALGORITHM_RAID10_NEAR)
 531                 n = copies;
 532
 533         else if (algorithm == ALGORITHM_RAID10_OFFSET) {
 534                 f = copies;
 535                 r = RAID10_OFFSET;
 536                 if (!_test_flag(CTR_FLAG_RAID10_USE_NEAR_SETS, rs->ctr_flags))
 537                         r |= RAID10_USE_FAR_SETS;
 538
 539         } else if (algorithm == ALGORITHM_RAID10_FAR) {
 540                 f = copies;
 541                 r = !RAID10_OFFSET;
 542                 if (!_test_flag(CTR_FLAG_RAID10_USE_NEAR_SETS, rs->ctr_flags))
 543                         r |= RAID10_USE_FAR_SETS;
 544
 545         } else
 546                 return -EINVAL;
 547
 548         return r | (f << RAID10_FAR_COPIES_SHIFT) | n;
 549 }
 550 /* END: MD raid10 bit definitions and helpers */
 551
 552 /* Check for any of the raid10 algorithms */
 553 static int _got_raid10(struct raid_type *rtp, const int layout)
 554 {
 555         if (rtp->level == 10) {
 556                 switch (rtp->algorithm) {
 557                 case ALGORITHM_RAID10_DEFAULT:
 558                 case ALGORITHM_RAID10_NEAR:
 559                         return _is_raid10_near(layout);
 560                 case ALGORITHM_RAID10_OFFSET:
 561                         return _is_raid10_offset(layout);
 562                 case ALGORITHM_RAID10_FAR:
 563                         return _is_raid10_far(layout);
 564                 default:
 565                         break;
 566                 }
 567         }
 568
 569         return 0;
 570 }
 571
 572 /* Return raid_type for @name */
 573 static struct raid_type *get_raid_type(const char *name)
 574 {
 575         struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
 576
 577         while (rtp-- > raid_types)
 578                 if (!strcasecmp(rtp->name, name))
 579                         return rtp;
 580
 581         return NULL;
 582 }
 583
 584 /* Return raid_type for @name based derived from @level and @layout */
 585 static struct raid_type *get_raid_type_by_ll(const int level, const int layout)
 586 {
 587         struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
 588
 589         while (rtp-- > raid_types) {
 590                 /* RAID10 special checks based on @layout flags/properties */
 591                 if (rtp->level == level &&
 592                     (_got_raid10(rtp, layout) || rtp->algorithm == layout))
 593                         return rtp;
 594         }
 595
 596         return NULL;
 597 }
 598
 599 /*
 600  * Set the mddev properties in @rs to the current
 601  * ones retrieved from the freshest superblock
 602  */
 603 static void rs_set_cur(struct raid_set *rs)
 604 {
 605         struct mddev *mddev = &rs->md;
 606
 607         mddev->new_level = mddev->level;
 608         mddev->new_layout = mddev->layout;
 609         mddev->new_chunk_sectors = mddev->chunk_sectors;
 610 }
 611
 612 /*
 613  * Set the mddev properties in @rs to the new
 614  * ones requested by the ctr
 615  */
 616 static void rs_set_new(struct raid_set *rs)
 617 {
 618         struct mddev *mddev = &rs->md;
 619
 620         mddev->level = mddev->new_level;
 621         mddev->layout = mddev->new_layout;
 622         mddev->chunk_sectors = mddev->new_chunk_sectors;
 623         mddev->raid_disks = rs->raid_disks;
 624         mddev->delta_disks = 0;
 625 }
 626
 627
 628 static struct raid_set *context_alloc(struct dm_target *ti, struct raid_type *raid_type, unsigned raid_devs)
 629 {
 630         unsigned i;
 631         struct raid_set *rs;
 632
 633         if (raid_devs <= raid_type->parity_devs) {
 634                 ti->error = "Insufficient number of devices";
 635                 return ERR_PTR(-EINVAL);
 636         }
 637
 638         rs = kzalloc(sizeof(*rs) + raid_devs * sizeof(rs->dev[0]), GFP_KERNEL);
 639         if (!rs) {
 640                 ti->error = "Cannot allocate raid context";
 641                 return ERR_PTR(-ENOMEM);
 642         }
 643
 644         mddev_init(&rs->md);
 645
 646         rs->raid_disks = raid_devs;
 647         rs->delta_disks = 0;
 648
 649         rs->ti = ti;
 650         rs->raid_type = raid_type;
 651         rs->md.raid_disks = raid_devs;
 652         rs->md.level = raid_type->level;
 653         rs->md.new_level = rs->md.level;
 654         rs->md.layout = raid_type->algorithm;
 655         rs->md.new_layout = rs->md.layout;
 656         rs->md.delta_disks = 0;
 657         rs->md.recovery_cp = rs_is_raid0(rs) ? MaxSector : 0;
 658
 659         for (i = 0; i < raid_devs; i++)
 660                 md_rdev_init(&rs->dev[i].rdev);
 661
 662         /*
 663          * Remaining items to be initialized by further RAID params:
 664          *  rs->md.persistent
 665          *  rs->md.external
 666          *  rs->md.chunk_sectors
 667          *  rs->md.new_chunk_sectors
 668          *  rs->md.dev_sectors
 669          */
 670
 671         return rs;
 672 }
 673
 674 static void context_free(struct raid_set *rs)
 675 {
 676         int i;
 677
 678         for (i = 0; i < rs->md.raid_disks; i++) {
 679                 if (rs->dev[i].meta_dev)
 680                         dm_put_device(rs->ti, rs->dev[i].meta_dev);
 681                 md_rdev_clear(&rs->dev[i].rdev);
 682                 if (rs->dev[i].data_dev)
 683                         dm_put_device(rs->ti, rs->dev[i].data_dev);
 684         }
 685
 686         kfree(rs);
 687 }
 688
 689 /*
 690  * For every device we have two words
 691  *  <meta_dev>: meta device name or '-' if missing
 692  *  <data_dev>: data device name or '-' if missing
 693  *
 694  * The following are permitted:
 695  *    - -
 696  *    - <data_dev>
 697  *    <meta_dev> <data_dev>
 698  *
 699  * The following is not allowed:
 700  *    <meta_dev> -
 701  *
 702  * This code parses those words.  If there is a failure,
 703  * the caller must use context_free to unwind the operations.
 704  */
 705 static int parse_dev_params(struct raid_set *rs, struct dm_arg_set *as)
 706 {
 707         int i;
 708         int rebuild = 0;
 709         int metadata_available = 0;
 710         int r = 0;
 711         const char *arg;
 712
 713         /* Put off the number of raid devices argument to get to dev pairs */
 714         arg = dm_shift_arg(as);
 715         if (!arg)
 716                 return -EINVAL;
 717
 718         for (i = 0; i < rs->md.raid_disks; i++) {
 719                 rs->dev[i].rdev.raid_disk = i;
 720
 721                 rs->dev[i].meta_dev = NULL;
 722                 rs->dev[i].data_dev = NULL;
 723
 724                 /*
 725                  * There are no offsets, since there is a separate device
 726                  * for data and metadata.
 727                  */
 728                 rs->dev[i].rdev.data_offset = 0;
 729                 rs->dev[i].rdev.mddev = &rs->md;
 730
 731                 arg = dm_shift_arg(as);
 732                 if (!arg)
 733                         return -EINVAL;
 734
 735                 if (strcmp(arg, "-")) {
 736                         r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
 737                                           &rs->dev[i].meta_dev);
 738                         if (r) {
 739                                 rs->ti->error = "RAID metadata device lookup failure";
 740                                 return r;
 741                         }
 742
 743                         rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
 744                         if (!rs->dev[i].rdev.sb_page) {
 745                                 rs->ti->error = "Failed to allocate superblock page";
 746                                 return -ENOMEM;
 747                         }
 748                 }
 749
 750                 arg = dm_shift_arg(as);
 751                 if (!arg)
 752                         return -EINVAL;
 753
 754                 if (!strcmp(arg, "-")) {
 755                         if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
 756                             (!rs->dev[i].rdev.recovery_offset)) {
 757                                 rs->ti->error = "Drive designated for rebuild not specified";
 758                                 return -EINVAL;
 759                         }
 760
 761                         if (rs->dev[i].meta_dev) {
 762                                 rs->ti->error = "No data device supplied with metadata device";
 763                                 return -EINVAL;
 764                         }
 765
 766                         continue;
 767                 }
 768
 769                 r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
 770                                   &rs->dev[i].data_dev);
 771                 if (r) {
 772                         rs->ti->error = "RAID device lookup failure";
 773                         return r;
 774                 }
 775
 776                 if (rs->dev[i].meta_dev) {
 777                         metadata_available = 1;
 778                         rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
 779                 }
 780                 rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
 781                 list_add_tail(&rs->dev[i].rdev.same_set, &rs->md.disks);
 782                 if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
 783                         rebuild++;
 784         }
 785
 786         if (metadata_available) {
 787                 rs->md.external = 0;
 788                 rs->md.persistent = 1;
 789                 rs->md.major_version = 2;
 790         } else if (rebuild && !rs->md.recovery_cp) {
 791                 /*
 792                  * Without metadata, we will not be able to tell if the array
 793                  * is in-sync or not - we must assume it is not.  Therefore,
 794                  * it is impossible to rebuild a drive.
 795                  *
 796                  * Even if there is metadata, the on-disk information may
 797                  * indicate that the array is not in-sync and it will then
 798                  * fail at that time.
 799                  *
 800                  * User could specify 'nosync' option if desperate.
 801                  */
 802                 rs->ti->error = "Unable to rebuild drive while array is not in-sync";
 803                 return -EINVAL;
 804         }
 805
 806         return 0;
 807 }
 808
 809 /*
 810  * validate_region_size
 811  * @rs
 812  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
 813  *
 814  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
 815  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
 816  *
 817  * Returns: 0 on success, -EINVAL on failure.
 818  */
 819 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
 820 {
 821         unsigned long min_region_size = rs->ti->len / (1 << 21);
 822
 823         if (!region_size) {
 824                 /*
 825                  * Choose a reasonable default.  All figures in sectors.
 826                  */
 827                 if (min_region_size > (1 << 13)) {
 828                         /* If not a power of 2, make it the next power of 2 */
 829                         region_size = roundup_pow_of_two(min_region_size);
 830                         DMINFO("Choosing default region size of %lu sectors",
 831                                region_size);
 832                 } else {
 833                         DMINFO("Choosing default region size of 4MiB");
 834                         region_size = 1 << 13; /* sectors */
 835                 }
 836         } else {
 837                 /*
 838                  * Validate user-supplied value.
 839                  */
 840                 if (region_size > rs->ti->len) {
 841                         rs->ti->error = "Supplied region size is too large";
 842                         return -EINVAL;
 843                 }
 844
 845                 if (region_size < min_region_size) {
 846                         DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
 847                               region_size, min_region_size);
 848                         rs->ti->error = "Supplied region size is too small";
 849                         return -EINVAL;
 850                 }
 851
 852                 if (!is_power_of_2(region_size)) {
 853                         rs->ti->error = "Region size is not a power of 2";
 854                         return -EINVAL;
 855                 }
 856
 857                 if (region_size < rs->md.chunk_sectors) {
 858                         rs->ti->error = "Region size is smaller than the chunk size";
 859                         return -EINVAL;
 860                 }
 861         }
 862
 863         /*
 864          * Convert sectors to bytes.
 865          */
 866         rs->md.bitmap_info.chunksize = (region_size << 9);
 867
 868         return 0;
 869 }
 870
 871 /*
 872  * validate_raid_redundancy
 873  * @rs
 874  *
 875  * Determine if there are enough devices in the array that haven't
 876  * failed (or are being rebuilt) to form a usable array.
 877  *
 878  * Returns: 0 on success, -EINVAL on failure.
 879  */
 880 static int validate_raid_redundancy(struct raid_set *rs)
 881 {
 882         unsigned i, rebuild_cnt = 0;
 883         unsigned rebuilds_per_group = 0, copies, d;
 884         unsigned group_size, last_group_start;
 885
 886         for (i = 0; i < rs->md.raid_disks; i++)
 887                 if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
 888                     !rs->dev[i].rdev.sb_page)
 889                         rebuild_cnt++;
 890
 891         switch (rs->raid_type->level) {
 892         case 1:
 893                 if (rebuild_cnt >= rs->md.raid_disks)
 894                         goto too_many;
 895                 break;
 896         case 4:
 897         case 5:
 898         case 6:
 899                 if (rebuild_cnt > rs->raid_type->parity_devs)
 900                         goto too_many;
 901                 break;
 902         case 10:
 903                 copies = raid10_md_layout_to_copies(rs->md.layout);
 904                 if (rebuild_cnt < copies)
 905                         break;
 906
 907                 /*
 908                  * It is possible to have a higher rebuild count for RAID10,
 909                  * as long as the failed devices occur in different mirror
 910                  * groups (i.e. different stripes).
 911                  *
 912                  * When checking "near" format, make sure no adjacent devices
 913                  * have failed beyond what can be handled.  In addition to the
 914                  * simple case where the number of devices is a multiple of the
 915                  * number of copies, we must also handle cases where the number
 916                  * of devices is not a multiple of the number of copies.
 917                  * E.g.    dev1 dev2 dev3 dev4 dev5
 918                  *          A    A    B    B    C
 919                  *          C    D    D    E    E
 920                  */
 921                 if (!strcmp("near", raid10_md_layout_to_format(rs->md.layout))) {
 922                         for (i = 0; i < rs->md.raid_disks * copies; i++) {
 923                                 if (!(i % copies))
 924                                         rebuilds_per_group = 0;
 925                                 d = i % rs->md.raid_disks;
 926                                 if ((!rs->dev[d].rdev.sb_page ||
 927                                      !test_bit(In_sync, &rs->dev[d].rdev.flags)) &&
 928                                     (++rebuilds_per_group >= copies))
 929                                         goto too_many;
 930                         }
 931                         break;
 932                 }
 933
 934                 /*
 935                  * When checking "far" and "offset" formats, we need to ensure
 936                  * that the device that holds its copy is not also dead or
 937                  * being rebuilt.  (Note that "far" and "offset" formats only
 938                  * support two copies right now.  These formats also only ever
 939                  * use the 'use_far_sets' variant.)
 940                  *
 941                  * This check is somewhat complicated by the need to account
 942                  * for arrays that are not a multiple of (far) copies.  This
 943                  * results in the need to treat the last (potentially larger)
 944                  * set differently.
 945                  */
 946                 group_size = (rs->md.raid_disks / copies);
 947                 last_group_start = (rs->md.raid_disks / group_size) - 1;
 948                 last_group_start *= group_size;
 949                 for (i = 0; i < rs->md.raid_disks; i++) {
 950                         if (!(i % copies) && !(i > last_group_start))
 951                                 rebuilds_per_group = 0;
 952                         if ((!rs->dev[i].rdev.sb_page ||
 953                              !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
 954                             (++rebuilds_per_group >= copies))
 955                                         goto too_many;
 956                 }
 957                 break;
 958         default:
 959                 if (rebuild_cnt)
 960                         return -EINVAL;
 961         }
 962
 963         return 0;
 964
 965 too_many:
 966         return -EINVAL;
 967 }
 968
 969 /*
 970  * Possible arguments are...
 971  *      <chunk_size> [optional_args]
 972  *
 973  * Argument definitions
 974  *    <chunk_size>                      The number of sectors per disk that
 975  *                                      will form the "stripe"
 976  *    [[no]sync]                        Force or prevent recovery of the
 977  *                                      entire array
 978  *    [rebuild <idx>]                   Rebuild the drive indicated by the index
 979  *    [daemon_sleep <ms>]               Time between bitmap daemon work to
 980  *                                      clear bits
 981  *    [min_recovery_rate <kB/sec/disk>] Throttle RAID initialization
 982  *    [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization
 983  *    [write_mostly <idx>]              Indicate a write mostly drive via index
 984  *    [max_write_behind <sectors>]      See '-write-behind=' (man mdadm)
 985  *    [stripe_cache <sectors>]          Stripe cache size for higher RAIDs
 986  *    [region_size <sectors>]           Defines granularity of bitmap
 987  *
 988  * RAID10-only options:
 989  *    [raid10_copies <# copies>]        Number of copies.  (Default: 2)
 990  *    [raid10_format <near|far|offset>] Layout algorithm.  (Default: near)
 991  */
 992 static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
 993                              unsigned num_raid_params)
 994 {
 995         int raid10_format = ALGORITHM_RAID10_DEFAULT;
 996         unsigned raid10_copies = 2;
 997         unsigned i;
 998         unsigned value, region_size = 0;
 999         sector_t sectors_per_dev = rs->ti->len;
1000         sector_t max_io_len;
1001         const char *arg, *key;
1002         struct raid_dev *rd;
1003         struct raid_type *rt = rs->raid_type;
1004
1005         arg = dm_shift_arg(as);
1006         num_raid_params--; /* Account for chunk_size argument */
1007
1008         if (kstrtouint(arg, 10, &value) < 0) {
1009                 rs->ti->error = "Bad numerical argument given for chunk_size";
1010                 return -EINVAL;
1011         }
1012
1013         /*
1014          * First, parse the in-order required arguments
1015          * "chunk_size" is the only argument of this type.
1016          */
1017         if (rt_is_raid1(rt)) {
1018                 if (value)
1019                         DMERR("Ignoring chunk size parameter for RAID 1");
1020                 value = 0;
1021         } else if (!is_power_of_2(value)) {
1022                 rs->ti->error = "Chunk size must be a power of 2";
1023                 return -EINVAL;
1024         } else if (value < 8) {
1025                 rs->ti->error = "Chunk size value is too small";
1026                 return -EINVAL;
1027         }
1028
1029         rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
1030
1031         /*
1032          * We set each individual device as In_sync with a completed
1033          * 'recovery_offset'.  If there has been a device failure or
1034          * replacement then one of the following cases applies:
1035          *
1036          *   1) User specifies 'rebuild'.
1037          *      - Device is reset when param is read.
1038          *   2) A new device is supplied.
1039          *      - No matching superblock found, resets device.
1040          *   3) Device failure was transient and returns on reload.
1041          *      - Failure noticed, resets device for bitmap replay.
1042          *   4) Device hadn't completed recovery after previous failure.
1043          *      - Superblock is read and overrides recovery_offset.
1044          *
1045          * What is found in the superblocks of the devices is always
1046          * authoritative, unless 'rebuild' or '[no]sync' was specified.
1047          */
1048         for (i = 0; i < rs->md.raid_disks; i++) {
1049                 set_bit(In_sync, &rs->dev[i].rdev.flags);
1050                 rs->dev[i].rdev.recovery_offset = MaxSector;
1051         }
1052
1053         /*
1054          * Second, parse the unordered optional arguments
1055          */
1056         for (i = 0; i < num_raid_params; i++) {
1057                 key = dm_shift_arg(as);
1058                 if (!key) {
1059                         rs->ti->error = "Not enough raid parameters given";
1060                         return -EINVAL;
1061                 }
1062
1063                 if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC))) {
1064                         if (_test_and_set_flag(CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1065                                 rs->ti->error = "Only one 'nosync' argument allowed";
1066                                 return -EINVAL;
1067                         }
1068                         rs->md.recovery_cp = MaxSector;
1069                         continue;
1070                 }
1071                 if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_SYNC))) {
1072                         if (_test_and_set_flag(CTR_FLAG_SYNC, &rs->ctr_flags)) {
1073                                 rs->ti->error = "Only one 'sync' argument allowed";
1074                                 return -EINVAL;
1075                         }
1076                         rs->md.recovery_cp = 0;
1077                         continue;
1078                 }
1079                 if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_USE_NEAR_SETS))) {
1080                         if (_test_and_set_flag(CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1081                                 rs->ti->error = "Only one 'raid10_use_new_sets' argument allowed";
1082                                 return -EINVAL;
1083                         }
1084                         continue;
1085                 }
1086
1087                 arg = dm_shift_arg(as);
1088                 i++; /* Account for the argument pairs */
1089                 if (!arg) {
1090                         rs->ti->error = "Wrong number of raid parameters given";
1091                         return -EINVAL;
1092                 }
1093
1094                 /*
1095                  * Parameters that take a string value are checked here.
1096                  */
1097
1098                 if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT))) {
1099                         if (_test_and_set_flag(CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags)) {
1100                                 rs->ti->error = "Only one 'raid10_format' argument pair allowed";
1101                                 return -EINVAL;
1102                         }
1103                         if (!rt_is_raid10(rt)) {
1104                                 rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
1105                                 return -EINVAL;
1106                         }
1107                         raid10_format = raid10_name_to_format(arg);
1108                         if (raid10_format < 0) {
1109                                 rs->ti->error = "Invalid 'raid10_format' value given";
1110                                 return raid10_format;
1111                         }
1112                         continue;
1113                 }
1114
1115                 if (kstrtouint(arg, 10, &value) < 0) {
1116                         rs->ti->error = "Bad numerical argument given in raid params";
1117                         return -EINVAL;
1118                 }
1119
1120                 if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD))) {
1121                         /*
1122                          * "rebuild" is being passed in by userspace to provide
1123                          * indexes of replaced devices and to set up additional
1124                          * devices on raid level takeover.
1125                          */
1126                         if (!_in_range(value, 0, rs->raid_disks - 1)) {
1127                                 rs->ti->error = "Invalid rebuild index given";
1128                                 return -EINVAL;
1129                         }
1130
1131                         if (test_and_set_bit(value, (void *) rs->rebuild_disks)) {
1132                                 rs->ti->error = "rebuild for this index already given";
1133                                 return -EINVAL;
1134                         }
1135
1136                         rd = rs->dev + value;
1137                         clear_bit(In_sync, &rd->rdev.flags);
1138                         clear_bit(Faulty, &rd->rdev.flags);
1139                         rd->rdev.recovery_offset = 0;
1140                         _set_flag(CTR_FLAG_REBUILD, &rs->ctr_flags);
1141                 } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY))) {
1142                         if (!rt_is_raid1(rt)) {
1143                                 rs->ti->error = "write_mostly option is only valid for RAID1";
1144                                 return -EINVAL;
1145                         }
1146
1147                         if (!_in_range(value, 0, rs->md.raid_disks - 1)) {
1148                                 rs->ti->error = "Invalid write_mostly index given";
1149                                 return -EINVAL;
1150                         }
1151
1152                         set_bit(WriteMostly, &rs->dev[value].rdev.flags);
1153                         _set_flag(CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags);
1154                 } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND))) {
1155                         if (!rt_is_raid1(rt)) {
1156                                 rs->ti->error = "max_write_behind option is only valid for RAID1";
1157                                 return -EINVAL;
1158                         }
1159
1160                         if (_test_and_set_flag(CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags)) {
1161                                 rs->ti->error = "Only one max_write_behind argument pair allowed";
1162                                 return -EINVAL;
1163                         }
1164
1165                         /*
1166                          * In device-mapper, we specify things in sectors, but
1167                          * MD records this value in kB
1168                          */
1169                         value /= 2;
1170                         if (value > COUNTER_MAX) {
1171                                 rs->ti->error = "Max write-behind limit out of range";
1172                                 return -EINVAL;
1173                         }
1174
1175                         rs->md.bitmap_info.max_write_behind = value;
1176                 } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP))) {
1177                         if (_test_and_set_flag(CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags)) {
1178                                 rs->ti->error = "Only one daemon_sleep argument pair allowed";
1179                                 return -EINVAL;
1180                         }
1181                         if (!value || (value > MAX_SCHEDULE_TIMEOUT)) {
1182                                 rs->ti->error = "daemon sleep period out of range";
1183                                 return -EINVAL;
1184                         }
1185                         rs->md.bitmap_info.daemon_sleep = value;
1186                 } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET))) {
1187                         /* Userspace passes new data_offset after having extended the the data image LV */
1188                         if (_test_and_set_flag(CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
1189                                 rs->ti->error = "Only one data_offset argument pair allowed";
1190                                 return -EINVAL;
1191                         }
1192                         /* Ensure sensible data offset */
1193                         if (value < 0) {
1194                                 rs->ti->error = "Bogus data_offset value";
1195                                 return -EINVAL;
1196                         }
1197                         rs->data_offset = value;
1198                 } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS))) {
1199                         /* Define the +/-# of disks to add to/remove from the given raid set */
1200                         if (_test_and_set_flag(CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
1201                                 rs->ti->error = "Only one delta_disks argument pair allowed";
1202                                 return -EINVAL;
1203                         }
1204                         /* Ensure MAX_RAID_DEVICES and raid type minimal_devs! */
1205                         if (!_in_range(abs(value), 1, MAX_RAID_DEVICES - rt->minimal_devs)) {
1206                                 rs->ti->error = "Too many delta_disk requested";
1207                                 return -EINVAL;
1208                         }
1209
1210                         rs->delta_disks = value;
1211                 } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE))) {
1212                         if (_test_and_set_flag(CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags)) {
1213                                 rs->ti->error = "Only one stripe_cache argument pair allowed";
1214                                 return -EINVAL;
1215                         }
1216
1217                         /*
1218                          * In device-mapper, we specify things in sectors, but
1219                          * MD records this value in kB
1220                          */
1221                         value /= 2;
1222
1223                         if (!rt_is_raid456(rt)) {
1224                                 rs->ti->error = "Inappropriate argument: stripe_cache";
1225                                 return -EINVAL;
1226                         }
1227                         if (raid5_set_cache_size(&rs->md, (int)value)) {
1228                                 rs->ti->error = "Bad stripe_cache size";
1229                                 return -EINVAL;
1230                         }
1231
1232                 } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE))) {
1233                         if (_test_and_set_flag(CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
1234                                 rs->ti->error = "Only one min_recovery_rate argument pair allowed";
1235                                 return -EINVAL;
1236                         }
1237                         if (value > INT_MAX) {
1238                                 rs->ti->error = "min_recovery_rate out of range";
1239                                 return -EINVAL;
1240                         }
1241                         rs->md.sync_speed_min = (int)value;
1242                 } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE))) {
1243                         if (_test_and_set_flag(CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
1244                                 rs->ti->error = "Only one max_recovery_rate argument pair allowed";
1245                                 return -EINVAL;
1246                         }
1247                         if (value > INT_MAX) {
1248                                 rs->ti->error = "max_recovery_rate out of range";
1249                                 return -EINVAL;
1250                         }
1251                         rs->md.sync_speed_max = (int)value;
1252                 } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE))) {
1253                         if (_test_and_set_flag(CTR_FLAG_REGION_SIZE, &rs->ctr_flags)) {
1254                                 rs->ti->error = "Only one region_size argument pair allowed";
1255                                 return -EINVAL;
1256                         }
1257
1258                         region_size = value;
1259                 } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES))) {
1260                         if (_test_and_set_flag(CTR_FLAG_RAID10_COPIES, &rs->ctr_flags)) {
1261                                 rs->ti->error = "Only one raid10_copies argument pair allowed";
1262                                 return -EINVAL;
1263                         }
1264
1265                         if (!_in_range(value, 2, rs->md.raid_disks)) {
1266                                 rs->ti->error = "Bad value for 'raid10_copies'";
1267                                 return -EINVAL;
1268                         }
1269
1270                         raid10_copies = value;
1271                 } else {
1272                         DMERR("Unable to parse RAID parameter: %s", key);
1273                         rs->ti->error = "Unable to parse RAID parameter";
1274                         return -EINVAL;
1275                 }
1276         }
1277
1278         if (validate_region_size(rs, region_size))
1279                 return -EINVAL;
1280
1281         if (rs->md.chunk_sectors)
1282                 max_io_len = rs->md.chunk_sectors;
1283         else
1284                 max_io_len = region_size;
1285
1286         if (dm_set_target_max_io_len(rs->ti, max_io_len))
1287                 return -EINVAL;
1288
1289         if (rt_is_raid10(rt)) {
1290                 if (raid10_copies > rs->md.raid_disks) {
1291                         rs->ti->error = "Not enough devices to satisfy specification";
1292                         return -EINVAL;
1293                 }
1294
1295                 rs->md.new_layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
1296                 if (rs->md.new_layout < 0) {
1297                         rs->ti->error = "Error getting raid10 format";
1298                         return rs->md.new_layout;
1299                 }
1300
1301                 rt = get_raid_type_by_ll(10, rs->md.new_layout);
1302                 if (!rt) {
1303                         rs->ti->error = "Failed to recognize new raid10 layout";
1304                         return -EINVAL;
1305                 }
1306
1307                 if ((rt->algorithm == ALGORITHM_RAID10_DEFAULT ||
1308                      rt->algorithm == ALGORITHM_RAID10_NEAR) &&
1309                     _test_flag(CTR_FLAG_RAID10_USE_NEAR_SETS, rs->ctr_flags)) {
1310                         rs->ti->error = "RAID10 format 'near' and 'raid10_use_near_sets' are incompatible";
1311                         return -EINVAL;
1312                 }
1313
1314                 /* (Len * #mirrors) / #devices */
1315                 sectors_per_dev = rs->ti->len * raid10_copies;
1316                 sector_div(sectors_per_dev, rs->md.raid_disks);
1317
1318                 rs->md.layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
1319                 rs->md.new_layout = rs->md.layout;
1320         } else if (!rt_is_raid1(rt) &&
1321                    sector_div(sectors_per_dev, (rs->md.raid_disks - rt->parity_devs))) {
1322                 rs->ti->error = "Target length not divisible by number of data devices";
1323                 return -EINVAL;
1324         }
1325
1326         rs->raid10_copies = raid10_copies;
1327         rs->md.dev_sectors = sectors_per_dev;
1328
1329         /* Assume there are no metadata devices until the drives are parsed */
1330         rs->md.persistent = 0;
1331         rs->md.external = 1;
1332
1333         /* Check, if any invalid ctr arguments have been passed in for the raid level */
1334         return rs_check_for_invalid_flags(rs);
1335 }
1336
1337 /* Return # of data stripes as kept in mddev as of @rs (i.e. as of superblock) */
1338 static unsigned int mddev_data_stripes(struct raid_set *rs)
1339 {
1340         return rs->md.raid_disks - rs->raid_type->parity_devs;
1341 }
1342
1343 static void do_table_event(struct work_struct *ws)
1344 {
1345         struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
1346
1347         dm_table_event(rs->ti->table);
1348 }
1349
1350 static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
1351 {
1352         struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
1353
1354         return mddev_congested(&rs->md, bits);
1355 }
1356
1357 /*
1358  * Make sure a valid takover (level switch) is being requested on @rs
1359  *
1360  * Conversions of raid sets from one MD personality to another
1361  * have to conform to restrictions which are enforced here.
1362  *
1363  * Degration is already checked for in rs_check_conversion() below.
1364  */
1365 static int rs_check_takeover(struct raid_set *rs)
1366 {
1367         struct mddev *mddev = &rs->md;
1368         unsigned int near_copies;
1369
1370         switch (mddev->level) {
1371         case 0:
1372                 /* raid0 -> raid1/5 with one disk */
1373                 if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1374                     mddev->raid_disks == 1)
1375                         return 0;
1376
1377                 /* raid0 -> raid10 */
1378                 if (mddev->new_level == 10 &&
1379                     !(rs->raid_disks % 2))
1380                         return 0;
1381
1382                 /* raid0 with multiple disks -> raid4/5/6 */
1383                 if (_in_range(mddev->new_level, 4, 6) &&
1384                     mddev->new_layout == ALGORITHM_PARITY_N &&
1385                     mddev->raid_disks > 1)
1386                         return 0;
1387
1388                 break;
1389
1390         case 10:
1391                 /* Can't takeover raid10_offset! */
1392                 if (_is_raid10_offset(mddev->layout))
1393                         break;
1394
1395                 near_copies = _raid10_near_copies(mddev->layout);
1396
1397                 /* raid10* -> raid0 */
1398                 if (mddev->new_level == 0) {
1399                         /* Can takeover raid10_near with raid disks divisable by data copies! */
1400                         if (near_copies > 1 &&
1401                             !(mddev->raid_disks % near_copies)) {
1402                                 mddev->raid_disks /= near_copies;
1403                                 mddev->delta_disks = mddev->raid_disks;
1404                                 return 0;
1405                         }
1406
1407                         /* Can takeover raid10_far */
1408                         if (near_copies == 1 &&
1409                            _raid10_far_copies(mddev->layout) > 1)
1410                                 return 0;
1411
1412                         break;
1413                 }
1414
1415                 /* raid10_{near,far} -> raid1 */
1416                 if (mddev->new_level == 1 &&
1417                     max(near_copies, _raid10_far_copies(mddev->layout)) == mddev->raid_disks)
1418                         return 0;
1419
1420                 /* raid10_{near,far} with 2 disks -> raid4/5 */
1421                 if (_in_range(mddev->new_level, 4, 5) &&
1422                     mddev->raid_disks == 2)
1423                         return 0;
1424                 break;
1425
1426         case 1:
1427                 /* raid1 with 2 disks -> raid4/5 */
1428                 if (_in_range(mddev->new_level, 4, 5) &&
1429                     mddev->raid_disks == 2) {
1430                         mddev->degraded = 1;
1431                         return 0;
1432                 }
1433
1434                 /* raid1 -> raid0 */
1435                 if (mddev->new_level == 0 &&
1436                     mddev->raid_disks == 1)
1437                         return 0;
1438
1439                 /* raid1 -> raid10 */
1440                 if (mddev->new_level == 10)
1441                         return 0;
1442
1443                 break;
1444
1445         case 4:
1446                 /* raid4 -> raid0 */
1447                 if (mddev->new_level == 0)
1448                         return 0;
1449
1450                 /* raid4 -> raid1/5 with 2 disks */
1451                 if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1452                     mddev->raid_disks == 2)
1453                         return 0;
1454
1455                 /* raid4 -> raid5/6 with parity N */
1456                 if (_in_range(mddev->new_level, 5, 6) &&
1457                     mddev->layout == ALGORITHM_PARITY_N)
1458                         return 0;
1459                 break;
1460
1461         case 5:
1462                 /* raid5 with parity N -> raid0 */
1463                 if (mddev->new_level == 0 &&
1464                     mddev->layout == ALGORITHM_PARITY_N)
1465                         return 0;
1466
1467                 /* raid5 with parity N -> raid4 */
1468                 if (mddev->new_level == 4 &&
1469                     mddev->layout == ALGORITHM_PARITY_N)
1470                         return 0;
1471
1472                 /* raid5 with 2 disks -> raid1/4/10 */
1473                 if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) &&
1474                     mddev->raid_disks == 2)
1475                         return 0;
1476
1477                 /* raid5 with parity N -> raid6 with parity N */
1478                 if (mddev->new_level == 6 &&
1479                     ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1480                       _in_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6)))
1481                         return 0;
1482                 break;
1483
1484         case 6:
1485                 /* raid6 with parity N -> raid0 */
1486                 if (mddev->new_level == 0 &&
1487                     mddev->layout == ALGORITHM_PARITY_N)
1488                         return 0;
1489
1490                 /* raid6 with parity N -> raid4 */
1491                 if (mddev->new_level == 4 &&
1492                     mddev->layout == ALGORITHM_PARITY_N)
1493                         return 0;
1494
1495                 /* raid6_*_n with parity N -> raid5_* */
1496                 if (mddev->new_level == 5 &&
1497                     ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1498                      _in_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC)))
1499                         return 0;
1500
1501         default:
1502                 break;
1503         }
1504
1505         rs->ti->error = "takeover not possible";
1506         return -EINVAL;
1507 }
1508
1509 /* True if @rs requested to be taken over */
1510 static bool rs_takeover_requested(struct raid_set *rs)
1511 {
1512         return rs->md.new_level != rs->md.level;
1513 }
1514
1515 /*  Features */
1516 #define FEATURE_FLAG_SUPPORTS_V190      0x1 /* Supports extended superblock */
1517
1518 /* State flags for sb->flags */
1519 #define SB_FLAG_RESHAPE_ACTIVE          0x1
1520 #define SB_FLAG_RESHAPE_BACKWARDS       0x2
1521
1522 /*
1523  * This structure is never routinely used by userspace, unlike md superblocks.
1524  * Devices with this superblock should only ever be accessed via device-mapper.
1525  */
1526 #define DM_RAID_MAGIC 0x64526D44
1527 struct dm_raid_superblock {
1528         __le32 magic;           /* "DmRd" */
1529         __le32 compat_features; /* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */
1530
1531         __le32 num_devices;     /* Number of devices in this raid set. (Max 64) */
1532         __le32 array_position;  /* The position of this drive in the raid set */
1533
1534         __le64 events;          /* Incremented by md when superblock updated */
1535         __le64 failed_devices;  /* Pre 1.9.0 part of bit field of devices to */
1536                                 /* indicate failures (see extension below) */
1537
1538         /*
1539          * This offset tracks the progress of the repair or replacement of
1540          * an individual drive.
1541          */
1542         __le64 disk_recovery_offset;
1543
1544         /*
1545          * This offset tracks the progress of the initial raid set
1546          * synchronisation/parity calculation.
1547          */
1548         __le64 array_resync_offset;
1549
1550         /*
1551          * raid characteristics
1552          */
1553         __le32 level;
1554         __le32 layout;
1555         __le32 stripe_sectors;
1556
1557         /********************************************************************
1558          * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
1559          *
1560          * FEATURE_FLAG_SUPPORTS_V190 in the features member indicates that those exist
1561          */
1562
1563         __le32 flags; /* Flags defining array states for reshaping */
1564
1565         /*
1566          * This offset tracks the progress of a raid
1567          * set reshape in order to be able to restart it
1568          */
1569         __le64 reshape_position;
1570
1571         /*
1572          * These define the properties of the array in case of an interrupted reshape
1573          */
1574         __le32 new_level;
1575         __le32 new_layout;
1576         __le32 new_stripe_sectors;
1577         __le32 delta_disks;
1578
1579         __le64 array_sectors; /* Array size in sectors */
1580
1581         /*
1582          * Sector offsets to data on devices (reshaping).
1583          * Needed to support out of place reshaping, thus
1584          * not writing over any stripes whilst converting
1585          * them from old to new layout
1586          */
1587         __le64 data_offset;
1588         __le64 new_data_offset;
1589
1590         __le64 sectors; /* Used device size in sectors */
1591
1592         /*
1593          * Additonal Bit field of devices indicating failures to support
1594          * up to 256 devices with the 1.9.0 on-disk metadata format
1595          */
1596         __le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];
1597
1598         __le32 incompat_features;       /* Used to indicate any incompatible features */
1599
1600         /* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
1601 } __packed;
1602
1603 static int read_disk_sb(struct md_rdev *rdev, int size)
1604 {
1605         BUG_ON(!rdev->sb_page);
1606
1607         if (rdev->sb_loaded)
1608                 return 0;
1609
1610         if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, 0, 1)) {
1611                 DMERR("Failed to read superblock of device at position %d",
1612                       rdev->raid_disk);
1613                 md_error(rdev->mddev, rdev);
1614                 return -EINVAL;
1615         }
1616
1617         rdev->sb_loaded = 1;
1618
1619         return 0;
1620 }
1621
1622 static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
1623 {
1624         failed_devices[0] = le64_to_cpu(sb->failed_devices);
1625         memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));
1626
1627         if (_test_flag(FEATURE_FLAG_SUPPORTS_V190, le32_to_cpu(sb->compat_features))) {
1628                 int i = ARRAY_SIZE(sb->extended_failed_devices);
1629
1630                 while (i--)
1631                         failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
1632         }
1633 }
1634
1635 static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
1636 {
1637         int i = ARRAY_SIZE(sb->extended_failed_devices);
1638
1639         sb->failed_devices = cpu_to_le64(failed_devices[0]);
1640         while (i--)
1641                 sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
1642 }
1643
1644 /*
1645  * Synchronize the superblock members with the raid set properties
1646  *
1647  * All superblock data is little endian.
1648  */
1649 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
1650 {
1651         bool update_failed_devices = false;
1652         unsigned int i;
1653         uint64_t failed_devices[DISKS_ARRAY_ELEMS];
1654         struct dm_raid_superblock *sb;
1655         struct raid_set *rs = container_of(mddev, struct raid_set, md);
1656
1657         /* No metadata device, no superblock */
1658         if (!rdev->meta_bdev)
1659                 return;
1660
1661         BUG_ON(!rdev->sb_page);
1662
1663         sb = page_address(rdev->sb_page);
1664
1665         sb_retrieve_failed_devices(sb, failed_devices);
1666
1667         for (i = 0; i < rs->raid_disks; i++)
1668                 if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
1669                         update_failed_devices = true;
1670                         set_bit(i, (void *) failed_devices);
1671                 }
1672
1673         if (update_failed_devices)
1674                 sb_update_failed_devices(sb, failed_devices);
1675
1676         sb->magic = cpu_to_le32(DM_RAID_MAGIC);
1677         sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
1678
1679         sb->num_devices = cpu_to_le32(mddev->raid_disks);
1680         sb->array_position = cpu_to_le32(rdev->raid_disk);
1681
1682         sb->events = cpu_to_le64(mddev->events);
1683
1684         sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
1685         sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
1686
1687         sb->level = cpu_to_le32(mddev->level);
1688         sb->layout = cpu_to_le32(mddev->layout);
1689         sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
1690
1691         sb->new_level = cpu_to_le32(mddev->new_level);
1692         sb->new_layout = cpu_to_le32(mddev->new_layout);
1693         sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
1694
1695         sb->delta_disks = cpu_to_le32(mddev->delta_disks);
1696
1697         smp_rmb(); /* Make sure we access most recent reshape position */
1698         sb->reshape_position = cpu_to_le64(mddev->reshape_position);
1699         if (le64_to_cpu(sb->reshape_position) != MaxSector) {
1700                 /* Flag ongoing reshape */
1701                 sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);
1702
1703                 if (mddev->delta_disks < 0 || mddev->reshape_backwards)
1704                         sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
1705         } else
1706                 /* Flag no reshape */
1707                 _clear_flags(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS), &sb->flags);
1708
1709         sb->array_sectors = cpu_to_le64(mddev->array_sectors);
1710         sb->data_offset = cpu_to_le64(rdev->data_offset);
1711         sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
1712         sb->sectors = cpu_to_le64(rdev->sectors);
1713
1714         /* Zero out the rest of the payload after the size of the superblock */
1715         memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
1716 }
1717
1718 /*
1719  * super_load
1720  *
1721  * This function creates a superblock if one is not found on the device
1722  * and will decide which superblock to use if there's a choice.
1723  *
1724  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
1725  */
1726 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
1727 {
1728         int r;
1729         struct dm_raid_superblock *sb;
1730         struct dm_raid_superblock *refsb;
1731         uint64_t events_sb, events_refsb;
1732
1733         rdev->sb_start = 0;
1734         rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
1735         if (rdev->sb_size < sizeof(*sb) || rdev->sb_size > PAGE_SIZE) {
1736                 DMERR("superblock size of a logical block is no longer valid");
1737                 return -EINVAL;
1738         }
1739
1740         r = read_disk_sb(rdev, rdev->sb_size);
1741         if (r)
1742                 return r;
1743
1744         sb = page_address(rdev->sb_page);
1745
1746         /*
1747          * Two cases that we want to write new superblocks and rebuild:
1748          * 1) New device (no matching magic number)
1749          * 2) Device specified for rebuild (!In_sync w/ offset == 0)
1750          */
1751         if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
1752             (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
1753                 super_sync(rdev->mddev, rdev);
1754
1755                 set_bit(FirstUse, &rdev->flags);
1756                 sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
1757
1758                 /* Force writing of superblocks to disk */
1759                 set_bit(MD_CHANGE_DEVS, &rdev->mddev->flags);
1760
1761                 /* Any superblock is better than none, choose that if given */
1762                 return refdev ? 0 : 1;
1763         }
1764
1765         if (!refdev)
1766                 return 1;
1767
1768         events_sb = le64_to_cpu(sb->events);
1769
1770         refsb = page_address(refdev->sb_page);
1771         events_refsb = le64_to_cpu(refsb->events);
1772
1773         return (events_sb > events_refsb) ? 1 : 0;
1774 }
1775
1776 static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
1777 {
1778         int role;
1779         unsigned int d;
1780         struct mddev *mddev = &rs->md;
1781         uint64_t events_sb;
1782         uint64_t failed_devices[DISKS_ARRAY_ELEMS];
1783         struct dm_raid_superblock *sb;
1784         uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
1785         struct md_rdev *r;
1786         struct dm_raid_superblock *sb2;
1787
1788         sb = page_address(rdev->sb_page);
1789         events_sb = le64_to_cpu(sb->events);
1790
1791         /*
1792          * Initialise to 1 if this is a new superblock.
1793          */
1794         mddev->events = events_sb ? : 1;
1795
1796         mddev->reshape_position = MaxSector;
1797
1798         /*
1799          * Reshaping is supported, e.g. reshape_position is valid
1800          * in superblock and superblock content is authoritative.
1801          */
1802         if (_test_flag(FEATURE_FLAG_SUPPORTS_V190, le32_to_cpu(sb->compat_features))) {
1803                 /* Superblock is authoritative wrt given raid set layout! */
1804                 mddev->raid_disks = le32_to_cpu(sb->num_devices);
1805                 mddev->level = le32_to_cpu(sb->level);
1806                 mddev->layout = le32_to_cpu(sb->layout);
1807                 mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);
1808                 mddev->new_level = le32_to_cpu(sb->new_level);
1809                 mddev->new_layout = le32_to_cpu(sb->new_layout);
1810                 mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
1811                 mddev->delta_disks = le32_to_cpu(sb->delta_disks);
1812                 mddev->array_sectors = le64_to_cpu(sb->array_sectors);
1813
1814                 /* raid was reshaping and got interrupted */
1815                 if (_test_flag(SB_FLAG_RESHAPE_ACTIVE, le32_to_cpu(sb->flags))) {
1816                         if (_test_flag(CTR_FLAG_DELTA_DISKS, rs->ctr_flags)) {
1817                                 DMERR("Reshape requested but raid set is still reshaping");
1818                                 return -EINVAL;
1819                         }
1820
1821                         if (mddev->delta_disks < 0 ||
1822                             (!mddev->delta_disks && _test_flag(SB_FLAG_RESHAPE_BACKWARDS, le32_to_cpu(sb->flags))))
1823                                 mddev->reshape_backwards = 1;
1824                         else
1825                                 mddev->reshape_backwards = 0;
1826
1827                         mddev->reshape_position = le64_to_cpu(sb->reshape_position);
1828                         rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
1829                 }
1830
1831         } else {
1832                 /*
1833                  * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
1834                  */
1835                 if (le32_to_cpu(sb->level) != mddev->level) {
1836                         DMERR("Reshaping/takeover raid sets not yet supported. (raid level/stripes/size change)");
1837                         return -EINVAL;
1838                 }
1839                 if (le32_to_cpu(sb->layout) != mddev->layout) {
1840                         DMERR("Reshaping raid sets not yet supported. (raid layout change)");
1841                         DMERR("  0x%X vs 0x%X", le32_to_cpu(sb->layout), mddev->layout);
1842                         DMERR("  Old layout: %s w/ %d copies",
1843                               raid10_md_layout_to_format(le32_to_cpu(sb->layout)),
1844                               raid10_md_layout_to_copies(le32_to_cpu(sb->layout)));
1845                         DMERR("  New layout: %s w/ %d copies",
1846                               raid10_md_layout_to_format(mddev->layout),
1847                               raid10_md_layout_to_copies(mddev->layout));
1848                         return -EINVAL;
1849                 }
1850                 if (le32_to_cpu(sb->stripe_sectors) != mddev->chunk_sectors) {
1851                         DMERR("Reshaping raid sets not yet supported. (stripe sectors change)");
1852                         return -EINVAL;
1853                 }
1854
1855                 /* We can only change the number of devices in raid1 with old (i.e. pre 1.0.7) metadata */
1856                 if (!rt_is_raid1(rs->raid_type) &&
1857                     (le32_to_cpu(sb->num_devices) != mddev->raid_disks)) {
1858                         DMERR("Reshaping raid sets not yet supported. (device count change from %u to %u)",
1859                               sb->num_devices, mddev->raid_disks);
1860                         return -EINVAL;
1861                 }
1862
1863                 /* Table line is checked vs. authoritative superblock */
1864                 rs_set_new(rs);
1865         }
1866
1867         if (!_test_flag(CTR_FLAG_NOSYNC, rs->ctr_flags))
1868                 mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
1869
1870         /*
1871          * During load, we set FirstUse if a new superblock was written.
1872          * There are two reasons we might not have a superblock:
1873          * 1) The raid set is brand new - in which case, all of the
1874          *    devices must have their In_sync bit set.  Also,
1875          *    recovery_cp must be 0, unless forced.
1876          * 2) This is a new device being added to an old raid set
1877          *    and the new device needs to be rebuilt - in which
1878          *    case the In_sync bit will /not/ be set and
1879          *    recovery_cp must be MaxSector.
1880          */
1881         d = 0;
1882         rdev_for_each(r, mddev) {
1883                 if (test_bit(FirstUse, &r->flags))
1884                         new_devs++;
1885
1886                 if (!test_bit(In_sync, &r->flags)) {
1887                         DMINFO("Device %d specified for rebuild; clearing superblock",
1888                                 r->raid_disk);
1889                         rebuilds++;
1890
1891                         if (test_bit(FirstUse, &r->flags))
1892                                 rebuild_and_new++;
1893                 }
1894
1895                 d++;
1896         }
1897
1898         if (new_devs == rs->raid_disks || !rebuilds) {
1899                 /* Replace a broken device */
1900                 if (new_devs == 1 && !rs->delta_disks)
1901                         ;
1902                 if (new_devs == rs->raid_disks) {
1903                         DMINFO("Superblocks created for new raid set");
1904                         set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
1905                         _set_flag(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
1906                         mddev->recovery_cp = 0;
1907                 } else if (new_devs && new_devs != rs->raid_disks && !rebuilds) {
1908                         DMERR("New device injected into existing raid set without "
1909                               "'delta_disks' or 'rebuild' parameter specified");
1910                         return -EINVAL;
1911                 }
1912         } else if (new_devs && new_devs != rebuilds) {
1913                 DMERR("%u 'rebuild' devices cannot be injected into"
1914                       " a raid set with %u other first-time devices",
1915                       rebuilds, new_devs);
1916                 return -EINVAL;
1917         } else if (rebuilds) {
1918                 if (rebuild_and_new && rebuilds != rebuild_and_new) {
1919                         DMERR("new device%s provided without 'rebuild'",
1920                               new_devs > 1 ? "s" : "");
1921                         return -EINVAL;
1922                 } else if (mddev->recovery_cp != MaxSector) {
1923                         DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
1924                               (unsigned long long) mddev->recovery_cp);
1925                         return -EINVAL;
1926                 } else if (mddev->reshape_position != MaxSector) {
1927                         DMERR("'rebuild' specified while raid set is being reshaped");
1928                         return -EINVAL;
1929                 }
1930         }
1931
1932         /*
1933          * Now we set the Faulty bit for those devices that are
1934          * recorded in the superblock as failed.
1935          */
1936         sb_retrieve_failed_devices(sb, failed_devices);
1937         rdev_for_each(r, mddev) {
1938                 if (!r->sb_page)
1939                         continue;
1940                 sb2 = page_address(r->sb_page);
1941                 sb2->failed_devices = 0;
1942                 memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));
1943
1944                 /*
1945                  * Check for any device re-ordering.
1946                  */
1947                 if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
1948                         role = le32_to_cpu(sb2->array_position);
1949                         if (role < 0)
1950                                 continue;
1951
1952                         if (role != r->raid_disk) {
1953                                 if (_is_raid10_near(mddev->layout)) {
1954                                         if (mddev->raid_disks % _raid10_near_copies(mddev->layout) ||
1955                                             rs->raid_disks % rs->raid10_copies) {
1956                                                 rs->ti->error =
1957                                                         "Cannot change raid10 near set to odd # of devices!";
1958                                                 return -EINVAL;
1959                                         }
1960
1961                                         sb2->array_position = cpu_to_le32(r->raid_disk);
1962
1963                                 } else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
1964                                            !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
1965                                            !rt_is_raid1(rs->raid_type)) {
1966                                         rs->ti->error = "Cannot change device positions in raid set";
1967                                         return -EINVAL;
1968                                 }
1969
1970                                 DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
1971                         }
1972
1973                         /*
1974                          * Partial recovery is performed on
1975                          * returning failed devices.
1976                          */
1977                         if (test_bit(role, (void *) failed_devices))
1978                                 set_bit(Faulty, &r->flags);
1979                 }
1980         }
1981
1982         return 0;
1983 }
1984
1985 static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
1986 {
1987         struct mddev *mddev = &rs->md;
1988         struct dm_raid_superblock *sb;
1989
1990         if (rs_is_raid0(rs) || !rdev->sb_page)
1991                 return 0;
1992
1993         sb = page_address(rdev->sb_page);
1994
1995         /*
1996          * If mddev->events is not set, we know we have not yet initialized
1997          * the array.
1998          */
1999         if (!mddev->events && super_init_validation(rs, rdev))
2000                 return -EINVAL;
2001
2002         if (le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
2003                 rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
2004                 return -EINVAL;
2005         }
2006
2007         if (sb->incompat_features) {
2008                 rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
2009                 return -EINVAL;
2010         }
2011
2012         /* Enable bitmap creation for RAID levels != 0 */
2013         mddev->bitmap_info.offset = rt_is_raid0(rs->raid_type) ? 0 : to_sector(4096);
2014         rdev->mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
2015
2016         if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
2017                 /* Retrieve device size stored in superblock to be prepared for shrink */
2018                 rdev->sectors = le64_to_cpu(sb->sectors);
2019                 rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
2020                 if (rdev->recovery_offset == MaxSector)
2021                         set_bit(In_sync, &rdev->flags);
2022                 /*
2023                  * If no reshape in progress -> we're recovering single
2024                  * disk(s) and have to set the device(s) to out-of-sync
2025                  */
2026                 else if (rs->md.reshape_position == MaxSector)
2027                         clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
2028         }
2029
2030         /*
2031          * If a device comes back, set it as not In_sync and no longer faulty.
2032          */
2033         if (test_and_clear_bit(Faulty, &rdev->flags)) {
2034                 rdev->recovery_offset = 0;
2035                 clear_bit(In_sync, &rdev->flags);
2036                 rdev->saved_raid_disk = rdev->raid_disk;
2037         }
2038
2039         /* Reshape support -> restore repective data offsets */
2040         rdev->data_offset = le64_to_cpu(sb->data_offset);
2041         rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);
2042
2043         return 0;
2044 }
2045
2046 /*
2047  * Analyse superblocks and select the freshest.
2048  */
2049 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
2050 {
2051         int r;
2052         struct raid_dev *dev;
2053         struct md_rdev *rdev, *tmp, *freshest;
2054         struct mddev *mddev = &rs->md;
2055
2056         freshest = NULL;
2057         rdev_for_each_safe(rdev, tmp, mddev) {
2058                 /*
2059                  * Skipping super_load due to CTR_FLAG_SYNC will cause
2060                  * the array to undergo initialization again as
2061                  * though it were new.  This is the intended effect
2062                  * of the "sync" directive.
2063                  *
2064                  * When reshaping capability is added, we must ensure
2065                  * that the "sync" directive is disallowed during the
2066                  * reshape.
2067                  */
2068                 if (_test_flag(CTR_FLAG_SYNC, rs->ctr_flags))
2069                         continue;
2070
2071                 if (!rdev->meta_bdev)
2072                         continue;
2073
2074                 r = super_load(rdev, freshest);
2075
2076                 switch (r) {
2077                 case 1:
2078                         freshest = rdev;
2079                         break;
2080                 case 0:
2081                         break;
2082                 default:
2083                         dev = container_of(rdev, struct raid_dev, rdev);
2084                         if (dev->meta_dev)
2085                                 dm_put_device(ti, dev->meta_dev);
2086
2087                         dev->meta_dev = NULL;
2088                         rdev->meta_bdev = NULL;
2089
2090                         if (rdev->sb_page)
2091                                 put_page(rdev->sb_page);
2092
2093                         rdev->sb_page = NULL;
2094
2095                         rdev->sb_loaded = 0;
2096
2097                         /*
2098                          * We might be able to salvage the data device
2099                          * even though the meta device has failed.  For
2100                          * now, we behave as though '- -' had been
2101                          * set for this device in the table.
2102                          */
2103                         if (dev->data_dev)
2104                                 dm_put_device(ti, dev->data_dev);
2105
2106                         dev->data_dev = NULL;
2107                         rdev->bdev = NULL;
2108
2109                         list_del(&rdev->same_set);
2110                 }
2111         }
2112
2113         if (!freshest)
2114                 return 0;
2115
2116         if (validate_raid_redundancy(rs)) {
2117                 rs->ti->error = "Insufficient redundancy to activate array";
2118                 return -EINVAL;
2119         }
2120
2121         /*
2122          * Validation of the freshest device provides the source of
2123          * validation for the remaining devices.
2124          */
2125         if (super_validate(rs, freshest)) {
2126                 rs->ti->error = "Unable to assemble array: Invalid superblocks";
2127                 return -EINVAL;
2128         }
2129
2130         rdev_for_each(rdev, mddev)
2131                 if ((rdev != freshest) && super_validate(rs, rdev))
2132                         return -EINVAL;
2133
2134         return 0;
2135 }
2136
2137 /* Userpace reordered disks -> adjust raid_disk indexes in @rs */
2138 static void _reorder_raid_disk_indexes(struct raid_set *rs)
2139 {
2140         int i = 0;
2141         struct md_rdev *rdev;
2142
2143         rdev_for_each(rdev, &rs->md) {
2144                 rdev->raid_disk = i++;
2145                 rdev->saved_raid_disk = rdev->new_raid_disk = -1;
2146         }
2147 }
2148
2149 /*
2150  * Setup @rs for takeover by a different raid level
2151  */
2152 static int rs_setup_takeover(struct raid_set *rs)
2153 {
2154         struct mddev *mddev = &rs->md;
2155         struct md_rdev *rdev;
2156         unsigned int d = mddev->raid_disks = rs->raid_disks;
2157         sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;
2158
2159         if (rt_is_raid10(rs->raid_type)) {
2160                 if (mddev->level == 0) {
2161                         /* Userpace reordered disks -> adjust raid_disk indexes */
2162                         _reorder_raid_disk_indexes(rs);
2163
2164                         /* raid0 -> raid10_far layout */
2165                         mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
2166                                                                    rs->raid10_copies);
2167                 } else if (mddev->level == 1)
2168                         /* raid1 -> raid10_near layout */
2169                         mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2170                                                                    rs->raid_disks);
2171                  else
2172                         return -EINVAL;
2173
2174         }
2175
2176         clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2177         mddev->recovery_cp = MaxSector;
2178
2179         while (d--) {
2180                 rdev = &rs->dev[d].rdev;
2181
2182                 if (test_bit(d, (void *) rs->rebuild_disks)) {
2183                         clear_bit(In_sync, &rdev->flags);
2184                         clear_bit(Faulty, &rdev->flags);
2185                         mddev->recovery_cp = rdev->recovery_offset = 0;
2186                         /* Bitmap has to be created when we do an "up" takeover */
2187                         set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2188                 }
2189
2190                 rdev->new_data_offset = new_data_offset;
2191         }
2192
2193         return 0;
2194 }
2195
2196 /*
2197  * Enable/disable discard support on RAID set depending on
2198  * RAID level and discard properties of underlying RAID members.
2199  */
2200 static void configure_discard_support(struct raid_set *rs)
2201 {
2202         int i;
2203         bool raid456;
2204         struct dm_target *ti = rs->ti;
2205
2206         /* Assume discards not supported until after checks below. */
2207         ti->discards_supported = false;
2208
2209         /* RAID level 4,5,6 require discard_zeroes_data for data integrity! */
2210         raid456 = (rs->md.level == 4 || rs->md.level == 5 || rs->md.level == 6);
2211
2212         for (i = 0; i < rs->md.raid_disks; i++) {
2213                 struct request_queue *q;
2214
2215                 if (!rs->dev[i].rdev.bdev)
2216                         continue;
2217
2218                 q = bdev_get_queue(rs->dev[i].rdev.bdev);
2219                 if (!q || !blk_queue_discard(q))
2220                         return;
2221
2222                 if (raid456) {
2223                         if (!q->limits.discard_zeroes_data)
2224                                 return;
2225                         if (!devices_handle_discard_safely) {
2226                                 DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
2227                                 DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
2228                                 return;
2229                         }
2230                 }
2231         }
2232
2233         /* All RAID members properly support discards */
2234         ti->discards_supported = true;
2235
2236         /*
2237          * RAID1 and RAID10 personalities require bio splitting,
2238          * RAID0/4/5/6 don't and process large discard bios properly.
2239          */
2240         ti->split_discard_bios = !!(rs->md.level == 1 || rs->md.level == 10);
2241         ti->num_discard_bios = 1;
2242 }
2243
2244 /*
2245  * Construct a RAID0/1/10/4/5/6 mapping:
2246  * Args:
2247  *      <raid_type> <#raid_params> <raid_params>{0,}    \
2248  *      <#raid_devs> [<meta_dev1> <dev1>]{1,}
2249  *
2250  * <raid_params> varies by <raid_type>.  See 'parse_raid_params' for
2251  * details on possible <raid_params>.
2252  *
2253  * Userspace is free to initialize the metadata devices, hence the superblocks to
2254  * enforce recreation based on the passed in table parameters.
2255  *
2256  */
2257 static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
2258 {
2259         int r;
2260         struct raid_type *rt;
2261         unsigned num_raid_params, num_raid_devs;
2262         struct raid_set *rs = NULL;
2263         const char *arg;
2264         struct dm_arg_set as = { argc, argv }, as_nrd;
2265         struct dm_arg _args[] = {
2266                 { 0, as.argc, "Cannot understand number of raid parameters" },
2267                 { 1, 254, "Cannot understand number of raid devices parameters" }
2268         };
2269
2270         /* Must have <raid_type> */
2271         arg = dm_shift_arg(&as);
2272         if (!arg) {
2273                 ti->error = "No arguments";
2274                 return -EINVAL;
2275         }
2276
2277         rt = get_raid_type(arg);
2278         if (!rt) {
2279                 ti->error = "Unrecognised raid_type";
2280                 return -EINVAL;
2281         }
2282
2283         /* Must have <#raid_params> */
2284         if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
2285                 return -EINVAL;
2286
2287         /* number of raid device tupples <meta_dev data_dev> */
2288         as_nrd = as;
2289         dm_consume_args(&as_nrd, num_raid_params);
2290         _args[1].max = (as_nrd.argc - 1) / 2;
2291         if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
2292                 return -EINVAL;
2293
2294         if (!_in_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
2295                 ti->error = "Invalid number of supplied raid devices";
2296                 return -EINVAL;
2297         }
2298
2299         rs = context_alloc(ti, rt, num_raid_devs);
2300         if (IS_ERR(rs))
2301                 return PTR_ERR(rs);
2302
2303         r = parse_raid_params(rs, &as, num_raid_params);
2304         if (r)
2305                 goto bad;
2306
2307         r = parse_dev_params(rs, &as);
2308         if (r)
2309                 goto bad;
2310
2311         rs->md.sync_super = super_sync;
2312
2313         /*
2314          * Backup any new raid set level, layout, ...
2315          * requested to be able to compare to superblock
2316          * members for conversion decisions.
2317          */
2318         rs_config_backup(rs);
2319
2320         r = analyse_superblocks(ti, rs);
2321         if (r)
2322                 goto bad;
2323
2324         INIT_WORK(&rs->md.event_work, do_table_event);
2325         ti->private = rs;
2326         ti->num_flush_bios = 1;
2327
2328         /* Restore any requested new layout for conversion decision */
2329         rs_config_restore(rs);
2330
2331         /*
2332          * If a takeover is needed, just set the level to
2333          * the new requested one and allow the raid set to run.
2334          */
2335         if (rs_takeover_requested(rs)) {
2336                 r = rs_check_takeover(rs);
2337                 if (r)
2338                         return r;
2339
2340                 r = rs_setup_takeover(rs);
2341                 if (r)
2342                         return r;
2343
2344                 /* Tell preresume to update superblocks with new layout */
2345                 _set_flag(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2346                 rs_set_new(rs);
2347         } else
2348                 rs_set_cur(rs);
2349
2350         /* Start raid set read-only and assumed clean to change in raid_resume() */
2351         rs->md.ro = 1;
2352         rs->md.in_sync = 1;
2353         set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
2354
2355         /* Has to be held on running the array */
2356         mddev_lock_nointr(&rs->md);
2357         r = md_run(&rs->md);
2358         rs->md.in_sync = 0; /* Assume already marked dirty */
2359         mddev_unlock(&rs->md);
2360
2361         if (r) {
2362                 ti->error = "Fail to run raid array";
2363                 goto bad;
2364         }
2365
2366         if (ti->len != rs->md.array_sectors) {
2367                 ti->error = "Array size does not match requested target length";
2368                 r = -EINVAL;
2369                 goto size_mismatch;
2370         }
2371         rs->callbacks.congested_fn = raid_is_congested;
2372         dm_table_add_target_callbacks(ti->table, &rs->callbacks);
2373
2374         mddev_suspend(&rs->md);
2375         return 0;
2376
2377 size_mismatch:
2378         md_stop(&rs->md);
2379 bad:
2380         context_free(rs);
2381
2382         return r;
2383 }
2384
2385 static void raid_dtr(struct dm_target *ti)
2386 {
2387         struct raid_set *rs = ti->private;
2388
2389         list_del_init(&rs->callbacks.list);
2390         md_stop(&rs->md);
2391         context_free(rs);
2392 }
2393
2394 static int raid_map(struct dm_target *ti, struct bio *bio)
2395 {
2396         struct raid_set *rs = ti->private;
2397         struct mddev *mddev = &rs->md;
2398
2399         mddev->pers->make_request(mddev, bio);
2400
2401         return DM_MAPIO_SUBMITTED;
2402 }
2403
2404 /* Return string describing the current sync action of @mddev */
2405 static const char *decipher_sync_action(struct mddev *mddev)
2406 {
2407         if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
2408                 return "frozen";
2409
2410         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
2411             (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
2412                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2413                         return "reshape";
2414
2415                 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2416                         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2417                                 return "resync";
2418                         else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
2419                                 return "check";
2420                         return "repair";
2421                 }
2422
2423                 if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
2424                         return "recover";
2425         }
2426
2427         return "idle";
2428 }
2429
2430 /*
2431  * Return status string @rdev
2432  *
2433  * Status characters:
2434  *
2435  *  'D' = Dead/Failed device
2436  *  'a' = Alive but not in-sync
2437  *  'A' = Alive and in-sync
2438  */
2439 static const char *_raid_dev_status(struct md_rdev *rdev, bool array_in_sync)
2440 {
2441         if (test_bit(Faulty, &rdev->flags))
2442                 return "D";
2443         else if (!array_in_sync || !test_bit(In_sync, &rdev->flags))
2444                 return "a";
2445         else
2446                 return "A";
2447 }
2448
2449 /* Helper to return resync/reshape progress for @rs and @array_in_sync */
2450 static sector_t rs_get_progress(struct raid_set *rs,
2451                                 sector_t resync_max_sectors, bool *array_in_sync)
2452 {
2453         sector_t r, recovery_cp, curr_resync_completed;
2454         struct mddev *mddev = &rs->md;
2455
2456         curr_resync_completed = mddev->curr_resync_completed ?: mddev->recovery_cp;
2457         recovery_cp = mddev->recovery_cp;
2458         *array_in_sync = false;
2459
2460         if (rs_is_raid0(rs)) {
2461                 r = resync_max_sectors;
2462                 *array_in_sync = true;
2463
2464         } else {
2465                 r = mddev->reshape_position;
2466
2467                 /* Reshape is relative to the array size */
2468                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) ||
2469                     r != MaxSector) {
2470                         if (r == MaxSector) {
2471                                 *array_in_sync = true;
2472                                 r = resync_max_sectors;
2473                         } else {
2474                                 /* Got to reverse on backward reshape */
2475                                 if (mddev->reshape_backwards)
2476                                         r = mddev->array_sectors - r;
2477
2478                                 /* Devide by # of data stripes */
2479                                 sector_div(r, mddev_data_stripes(rs));
2480                         }
2481
2482                 /* Sync is relative to the component device size */
2483                 } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
2484                         r = curr_resync_completed;
2485                 else
2486                         r = recovery_cp;
2487
2488                 if (r == MaxSector) {
2489                         /*
2490                          * Sync complete.
2491                          */
2492                         *array_in_sync = true;
2493                         r = resync_max_sectors;
2494                 } else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2495                         /*
2496                          * If "check" or "repair" is occurring, the raid set has
2497                          * undergone an initial sync and the health characters
2498                          * should not be 'a' anymore.
2499                          */
2500                         *array_in_sync = true;
2501                 } else {
2502                         struct md_rdev *rdev;
2503
2504                         /*
2505                          * The raid set may be doing an initial sync, or it may
2506                          * be rebuilding individual components.  If all the
2507                          * devices are In_sync, then it is the raid set that is
2508                          * being initialized.
2509                          */
2510                         rdev_for_each(rdev, mddev)
2511                                 if (!test_bit(In_sync, &rdev->flags))
2512                                         *array_in_sync = true;
2513 #if 0
2514                         r = 0; /* HM FIXME: TESTME: https://bugzilla.redhat.com/show_bug.cgi?id=1210637 ? */
2515 #endif
2516                 }
2517         }
2518
2519         return r;
2520 }
2521
2522 /* Helper to return @dev name or "-" if !@dev */
2523 static const char *_get_dev_name(struct dm_dev *dev)
2524 {
2525         return dev ? dev->name : "-";
2526 }
2527
2528 static void raid_status(struct dm_target *ti, status_type_t type,
2529                         unsigned int status_flags, char *result, unsigned int maxlen)
2530 {
2531         struct raid_set *rs = ti->private;
2532         struct mddev *mddev = &rs->md;
2533         struct r5conf *conf = mddev->private;
2534         int max_nr_stripes = conf ? conf->max_nr_stripes : 0;
2535         bool array_in_sync;
2536         unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
2537         unsigned int sz = 0;
2538         unsigned int write_mostly_params = 0;
2539         sector_t progress, resync_max_sectors, resync_mismatches;
2540         const char *sync_action;
2541         struct raid_type *rt;
2542         struct md_rdev *rdev;
2543
2544         switch (type) {
2545         case STATUSTYPE_INFO:
2546                 /* *Should* always succeed */
2547                 rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
2548                 if (!rt)
2549                         return;
2550
2551                 DMEMIT("%s %d ", rt ? rt->name : "unknown", mddev->raid_disks);
2552
2553                 /* Access most recent mddev properties for status output */
2554                 smp_rmb();
2555                 /* Get sensible max sectors even if raid set not yet started */
2556                 resync_max_sectors = _test_flag(RT_FLAG_RS_PRERESUMED, rs->runtime_flags) ?
2557                                       mddev->resync_max_sectors : mddev->dev_sectors;
2558                 progress = rs_get_progress(rs, resync_max_sectors, &array_in_sync);
2559                 resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ?
2560                                     (unsigned int) atomic64_read(&mddev->resync_mismatches) : 0;
2561                 sync_action = decipher_sync_action(&rs->md);
2562
2563                 /* HM FIXME: do we want another state char for raid0? It shows 'D' or 'A' now */
2564                 rdev_for_each(rdev, mddev)
2565                         DMEMIT(_raid_dev_status(rdev, array_in_sync));
2566
2567                 /*
2568                  * In-sync/Reshape ratio:
2569                  *  The in-sync ratio shows the progress of:
2570                  *   - Initializing the raid set
2571                  *   - Rebuilding a subset of devices of the raid set
2572                  *  The user can distinguish between the two by referring
2573                  *  to the status characters.
2574                  *
2575                  *  The reshape ratio shows the progress of
2576                  *  changing the raid layout or the number of
2577                  *  disks of a raid set
2578                  */
2579                 DMEMIT(" %llu/%llu", (unsigned long long) progress,
2580                                      (unsigned long long) resync_max_sectors);
2581
2582                 /*
2583                  * v1.5.0+:
2584                  *
2585                  * Sync action:
2586                  *   See Documentation/device-mapper/dm-raid.txt for
2587                  *   information on each of these states.
2588                  */
2589                 DMEMIT(" %s", sync_action);
2590
2591                 /*
2592                  * v1.5.0+:
2593                  *
2594                  * resync_mismatches/mismatch_cnt
2595                  *   This field shows the number of discrepancies found when
2596                  *   performing a "check" of the raid set.
2597                  */
2598                 DMEMIT(" %llu", (unsigned long long) resync_mismatches);
2599
2600                 /*
2601                  * v1.9.0+:
2602                  *
2603                  * data_offset (needed for out of space reshaping)
2604                  *   This field shows the data offset into the data
2605                  *   image LV where the first stripes data starts.
2606                  *
2607                  * We keep data_offset equal on all raid disks of the set,
2608                  * so retrieving it from the first raid disk is sufficient.
2609                  */
2610                 DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);
2611                 break;
2612
2613         case STATUSTYPE_TABLE:
2614                 /* Report the table line string you would use to construct this raid set */
2615
2616                 /* Calculate raid parameter count */
2617                 rdev_for_each(rdev, mddev)
2618                         if (test_bit(WriteMostly, &rdev->flags))
2619                                 write_mostly_params += 2;
2620                 raid_param_cnt += memweight(rs->rebuild_disks,
2621                                             DISKS_ARRAY_ELEMS * sizeof(*rs->rebuild_disks)) * 2 +
2622                                   write_mostly_params +
2623                                   hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
2624                                   hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2;
2625                 /* Emit table line */
2626                 DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
2627                 if (_test_flag(CTR_FLAG_RAID10_FORMAT, rs->ctr_flags))
2628                         DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
2629                                          raid10_md_layout_to_format(mddev->layout));
2630                 if (_test_flag(CTR_FLAG_RAID10_COPIES, rs->ctr_flags))
2631                         DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
2632                                          raid10_md_layout_to_copies(mddev->layout));
2633                 if (_test_flag(CTR_FLAG_NOSYNC, rs->ctr_flags))
2634                         DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
2635                 if (_test_flag(CTR_FLAG_SYNC, rs->ctr_flags))
2636                         DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
2637                 if (_test_flag(CTR_FLAG_REGION_SIZE, rs->ctr_flags))
2638                         DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
2639                                            (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
2640                 if (_test_flag(CTR_FLAG_DATA_OFFSET, rs->ctr_flags))
2641                         DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
2642                                            (unsigned long long) rs->data_offset);
2643                 if (_test_flag(CTR_FLAG_DAEMON_SLEEP, rs->ctr_flags))
2644                         DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
2645                                           mddev->bitmap_info.daemon_sleep);
2646                 if (_test_flag(CTR_FLAG_DELTA_DISKS, rs->ctr_flags))
2647                         DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
2648                                          mddev->delta_disks);
2649                 if (_test_flag(CTR_FLAG_STRIPE_CACHE, rs->ctr_flags))
2650                         DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
2651                                          max_nr_stripes);
2652                 rdev_for_each(rdev, mddev)
2653                         if (test_bit(rdev->raid_disk, (void *) rs->rebuild_disks))
2654                                 DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD),
2655                                                  rdev->raid_disk);
2656                 rdev_for_each(rdev, mddev)
2657                         if (test_bit(WriteMostly, &rdev->flags))
2658                                 DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
2659                                                  rdev->raid_disk);
2660                 if (_test_flag(CTR_FLAG_MAX_WRITE_BEHIND, rs->ctr_flags))
2661                         DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
2662                                           mddev->bitmap_info.max_write_behind);
2663                 if (_test_flag(CTR_FLAG_MAX_RECOVERY_RATE, rs->ctr_flags))
2664                         DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
2665                                          mddev->sync_speed_max);
2666                 if (_test_flag(CTR_FLAG_MIN_RECOVERY_RATE, rs->ctr_flags))
2667                         DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
2668                                          mddev->sync_speed_min);
2669                 DMEMIT(" %d", rs->raid_disks);
2670                 rdev_for_each(rdev, mddev) {
2671                         struct raid_dev *rd = container_of(rdev, struct raid_dev, rdev);
2672
2673                         DMEMIT(" %s %s", _get_dev_name(rd->meta_dev),
2674                                          _get_dev_name(rd->data_dev));
2675                 }
2676         }
2677 }
2678
2679 static int raid_message(struct dm_target *ti, unsigned argc, char **argv)
2680 {
2681         struct raid_set *rs = ti->private;
2682         struct mddev *mddev = &rs->md;
2683
2684         if (!strcasecmp(argv[0], "reshape")) {
2685                 DMERR("Reshape not supported.");
2686                 return -EINVAL;
2687         }
2688
2689         if (!mddev->pers || !mddev->pers->sync_request)
2690                 return -EINVAL;
2691
2692         if (!strcasecmp(argv[0], "frozen"))
2693                 set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
2694         else
2695                 clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
2696
2697         if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
2698                 if (mddev->sync_thread) {
2699                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2700                         md_reap_sync_thread(mddev);
2701                 }
2702         } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
2703                    test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
2704                 return -EBUSY;
2705         else if (!strcasecmp(argv[0], "resync"))
2706                 ; /* MD_RECOVERY_NEEDED set below */
2707         else if (!strcasecmp(argv[0], "recover"))
2708                 set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
2709         else {
2710                 if (!strcasecmp(argv[0], "check"))
2711                         set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
2712                 else if (!!strcasecmp(argv[0], "repair"))
2713                         return -EINVAL;
2714                 set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
2715                 set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
2716         }
2717         if (mddev->ro == 2) {
2718                 /* A write to sync_action is enough to justify
2719                  * canceling read-auto mode
2720                  */
2721                 mddev->ro = 0;
2722                 if (!mddev->suspended && mddev->sync_thread)
2723                         md_wakeup_thread(mddev->sync_thread);
2724         }
2725         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2726         if (!mddev->suspended && mddev->thread)
2727                 md_wakeup_thread(mddev->thread);
2728
2729         return 0;
2730 }
2731
2732 static int raid_iterate_devices(struct dm_target *ti,
2733                                 iterate_devices_callout_fn fn, void *data)
2734 {
2735         struct raid_set *rs = ti->private;
2736         unsigned i;
2737         int r = 0;
2738
2739         for (i = 0; !r && i < rs->md.raid_disks; i++)
2740                 if (rs->dev[i].data_dev)
2741                         r = fn(ti,
2742                                  rs->dev[i].data_dev,
2743                                  0, /* No offset on data devs */
2744                                  rs->md.dev_sectors,
2745                                  data);
2746
2747         return r;
2748 }
2749
2750 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
2751 {
2752         struct raid_set *rs = ti->private;
2753         unsigned chunk_size = rs->md.chunk_sectors << 9;
2754         struct r5conf *conf = rs->md.private;
2755
2756         blk_limits_io_min(limits, chunk_size);
2757         blk_limits_io_opt(limits, chunk_size * (conf->raid_disks - conf->max_degraded));
2758 }
2759
2760 static void raid_presuspend(struct dm_target *ti)
2761 {
2762         struct raid_set *rs = ti->private;
2763
2764         md_stop_writes(&rs->md);
2765 }
2766
2767 static void raid_postsuspend(struct dm_target *ti)
2768 {
2769         struct raid_set *rs = ti->private;
2770
2771         mddev_suspend(&rs->md);
2772 }
2773
2774 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
2775 {
2776         int i;
2777         uint64_t failed_devices, cleared_failed_devices = 0;
2778         unsigned long flags;
2779         struct dm_raid_superblock *sb;
2780         struct md_rdev *r;
2781
2782         for (i = 0; i < rs->md.raid_disks; i++) {
2783                 r = &rs->dev[i].rdev;
2784                 if (test_bit(Faulty, &r->flags) && r->sb_page &&
2785                     sync_page_io(r, 0, r->sb_size, r->sb_page, REQ_OP_READ, 0,
2786                                  1)) {
2787                         DMINFO("Faulty %s device #%d has readable super block."
2788                                "  Attempting to revive it.",
2789                                rs->raid_type->name, i);
2790
2791                         /*
2792                          * Faulty bit may be set, but sometimes the array can
2793                          * be suspended before the personalities can respond
2794                          * by removing the device from the array (i.e. calling
2795                          * 'hot_remove_disk').  If they haven't yet removed
2796                          * the failed device, its 'raid_disk' number will be
2797                          * '>= 0' - meaning we must call this function
2798                          * ourselves.
2799                          */
2800                         if ((r->raid_disk >= 0) &&
2801                             (r->mddev->pers->hot_remove_disk(r->mddev, r) != 0))
2802                                 /* Failed to revive this device, try next */
2803                                 continue;
2804
2805                         r->raid_disk = i;
2806                         r->saved_raid_disk = i;
2807                         flags = r->flags;
2808                         clear_bit(Faulty, &r->flags);
2809                         clear_bit(WriteErrorSeen, &r->flags);
2810                         clear_bit(In_sync, &r->flags);
2811                         if (r->mddev->pers->hot_add_disk(r->mddev, r)) {
2812                                 r->raid_disk = -1;
2813                                 r->saved_raid_disk = -1;
2814                                 r->flags = flags;
2815                         } else {
2816                                 r->recovery_offset = 0;
2817                                 cleared_failed_devices |= 1 << i;
2818                         }
2819                 }
2820         }
2821         if (cleared_failed_devices) {
2822                 rdev_for_each(r, &rs->md) {
2823                         sb = page_address(r->sb_page);
2824                         failed_devices = le64_to_cpu(sb->failed_devices);
2825                         failed_devices &= ~cleared_failed_devices;
2826                         sb->failed_devices = cpu_to_le64(failed_devices);
2827                 }
2828         }
2829 }
2830
2831 /* Load the dirty region bitmap */
2832 static int _bitmap_load(struct raid_set *rs)
2833 {
2834         int r = 0;
2835
2836         /* Try loading the bitmap unless "raid0", which does not have one */
2837         if (!rs_is_raid0(rs) &&
2838             !_test_and_set_flag(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
2839                 r = bitmap_load(&rs->md);
2840                 if (r)
2841                         DMERR("Failed to load bitmap");
2842         }
2843
2844         return r;
2845 }
2846
2847 static int raid_preresume(struct dm_target *ti)
2848 {
2849         struct raid_set *rs = ti->private;
2850         struct mddev *mddev = &rs->md;
2851
2852         /* This is a resume after a suspend of the set -> it's already started */
2853         if (_test_and_set_flag(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
2854                 return 0;
2855
2856         /*
2857          * The superblocks need to be updated on disk if the
2858          * array is new or _bitmap_load will overwrite them
2859          * in core with old data.
2860          *
2861          * In case the array got modified (takeover/reshape/resize)
2862          * or the data offsets on the component devices changed, they
2863          * have to be updated as well.
2864          *
2865          * Have to switch to readwrite and back in order to
2866          * allow for the superblock updates.
2867          */
2868         if (_test_and_clear_flag(RT_FLAG_UPDATE_SBS, &rs->runtime_flags)) {
2869                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2870                 mddev->ro = 0;
2871                 md_update_sb(mddev, 1);
2872                 mddev->ro = 1;
2873         }
2874
2875         /*
2876          * Disable/enable discard support on raid set after any
2877          * conversion, because devices can have been added
2878          */
2879         configure_discard_support(rs);
2880
2881         /* Load the bitmap from disk unless raid0 */
2882         return _bitmap_load(rs);
2883 }
2884
2885 static void raid_resume(struct dm_target *ti)
2886 {
2887         struct raid_set *rs = ti->private;
2888         struct mddev *mddev = &rs->md;
2889
2890         if (_test_and_set_flag(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
2891                 /*
2892                  * A secondary resume while the device is active.
2893                  * Take this opportunity to check whether any failed
2894                  * devices are reachable again.
2895                  */
2896                 attempt_restore_of_faulty_devices(rs);
2897         }
2898
2899         mddev->ro = 0;
2900         mddev->in_sync = 0;
2901         clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
2902
2903         if (mddev->suspended)
2904                 mddev_resume(mddev);
2905 }
2906
2907 static struct target_type raid_target = {
2908         .name = "raid",
2909         .version = {1, 9, 0},
2910         .module = THIS_MODULE,
2911         .ctr = raid_ctr,
2912         .dtr = raid_dtr,
2913         .map = raid_map,
2914         .status = raid_status,
2915         .message = raid_message,
2916         .iterate_devices = raid_iterate_devices,
2917         .io_hints = raid_io_hints,
2918         .presuspend = raid_presuspend,
2919         .postsuspend = raid_postsuspend,
2920         .preresume = raid_preresume,
2921         .resume = raid_resume,
2922 };
2923
2924 static int __init dm_raid_init(void)
2925 {
2926         DMINFO("Loading target version %u.%u.%u",
2927                raid_target.version[0],
2928                raid_target.version[1],
2929                raid_target.version[2]);
2930         return dm_register_target(&raid_target);
2931 }
2932
2933 static void __exit dm_raid_exit(void)
2934 {
2935         dm_unregister_target(&raid_target);
2936 }
2937
2938 module_init(dm_raid_init);
2939 module_exit(dm_raid_exit);
2940
2941 module_param(devices_handle_discard_safely, bool, 0644);
2942 MODULE_PARM_DESC(devices_handle_discard_safely,
2943                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
2944
2945 MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
2946 MODULE_ALIAS("dm-raid0");
2947 MODULE_ALIAS("dm-raid1");
2948 MODULE_ALIAS("dm-raid10");
2949 MODULE_ALIAS("dm-raid4");
2950 MODULE_ALIAS("dm-raid5");
2951 MODULE_ALIAS("dm-raid6");
2952 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
2953 MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
2954 MODULE_LICENSE("GPL");