drivers/md/raid0.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3    raid0.c : Multiple Devices driver for Linux
   4              Copyright (C) 1994-96 Marc ZYNGIER
   5              <zyngier@ufr-info-p7.ibp.fr> or
   6              <maz@gloups.fdn.fr>
   7              Copyright (C) 1999, 2000 Ingo Molnar, Red Hat
   8
   9    RAID-0 management functions.
  10
  11 */
  12
  13 #include <linux/blkdev.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/module.h>
  16 #include <linux/slab.h>
  17 #include <trace/events/block.h>
  18 #include "md.h"
  19 #include "raid0.h"
  20 #include "raid5.h"
  21
  22 static int default_layout = 0;
  23 module_param(default_layout, int, 0644);
  24
  25 #define UNSUPPORTED_MDDEV_FLAGS         \
  26         ((1L << MD_HAS_JOURNAL) |       \
  27          (1L << MD_JOURNAL_CLEAN) |     \
  28          (1L << MD_FAILFAST_SUPPORTED) |\
  29          (1L << MD_HAS_PPL) |           \
  30          (1L << MD_HAS_MULTIPLE_PPLS))
  31
  32 /*
  33  * inform the user of the raid configuration
  34 */
  35 static void dump_zones(struct mddev *mddev)
  36 {
  37         int j, k;
  38         sector_t zone_size = 0;
  39         sector_t zone_start = 0;
  40         char b[BDEVNAME_SIZE];
  41         struct r0conf *conf = mddev->private;
  42         int raid_disks = conf->strip_zone[0].nb_dev;
  43         pr_debug("md: RAID0 configuration for %s - %d zone%s\n",
  44                  mdname(mddev),
  45                  conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s");
  46         for (j = 0; j < conf->nr_strip_zones; j++) {
  47                 char line[200];
  48                 int len = 0;
  49
  50                 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
  51                         len += snprintf(line+len, 200-len, "%s%s", k?"/":"",
  52                                         bdevname(conf->devlist[j*raid_disks
  53                                                                + k]->bdev, b));
  54                 pr_debug("md: zone%d=[%s]\n", j, line);
  55
  56                 zone_size  = conf->strip_zone[j].zone_end - zone_start;
  57                 pr_debug("      zone-offset=%10lluKB, device-offset=%10lluKB, size=%10lluKB\n",
  58                         (unsigned long long)zone_start>>1,
  59                         (unsigned long long)conf->strip_zone[j].dev_start>>1,
  60                         (unsigned long long)zone_size>>1);
  61                 zone_start = conf->strip_zone[j].zone_end;
  62         }
  63 }
  64
  65 static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
  66 {
  67         int i, c, err;
  68         sector_t curr_zone_end, sectors;
  69         struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
  70         struct strip_zone *zone;
  71         int cnt;
  72         char b[BDEVNAME_SIZE];
  73         char b2[BDEVNAME_SIZE];
  74         struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
  75         unsigned blksize = 512;
  76
  77         *private_conf = ERR_PTR(-ENOMEM);
  78         if (!conf)
  79                 return -ENOMEM;
  80         rdev_for_each(rdev1, mddev) {
  81                 pr_debug("md/raid0:%s: looking at %s\n",
  82                          mdname(mddev),
  83                          bdevname(rdev1->bdev, b));
  84                 c = 0;
  85
  86                 /* round size to chunk_size */
  87                 sectors = rdev1->sectors;
  88                 sector_div(sectors, mddev->chunk_sectors);
  89                 rdev1->sectors = sectors * mddev->chunk_sectors;
  90
  91                 blksize = max(blksize, queue_logical_block_size(
  92                                       rdev1->bdev->bd_disk->queue));
  93
  94                 rdev_for_each(rdev2, mddev) {
  95                         pr_debug("md/raid0:%s:   comparing %s(%llu)"
  96                                  " with %s(%llu)\n",
  97                                  mdname(mddev),
  98                                  bdevname(rdev1->bdev,b),
  99                                  (unsigned long long)rdev1->sectors,
 100                                  bdevname(rdev2->bdev,b2),
 101                                  (unsigned long long)rdev2->sectors);
 102                         if (rdev2 == rdev1) {
 103                                 pr_debug("md/raid0:%s:   END\n",
 104                                          mdname(mddev));
 105                                 break;
 106                         }
 107                         if (rdev2->sectors == rdev1->sectors) {
 108                                 /*
 109                                  * Not unique, don't count it as a new
 110                                  * group
 111                                  */
 112                                 pr_debug("md/raid0:%s:   EQUAL\n",
 113                                          mdname(mddev));
 114                                 c = 1;
 115                                 break;
 116                         }
 117                         pr_debug("md/raid0:%s:   NOT EQUAL\n",
 118                                  mdname(mddev));
 119                 }
 120                 if (!c) {
 121                         pr_debug("md/raid0:%s:   ==> UNIQUE\n",
 122                                  mdname(mddev));
 123                         conf->nr_strip_zones++;
 124                         pr_debug("md/raid0:%s: %d zones\n",
 125                                  mdname(mddev), conf->nr_strip_zones);
 126                 }
 127         }
 128         pr_debug("md/raid0:%s: FINAL %d zones\n",
 129                  mdname(mddev), conf->nr_strip_zones);
 130
 131         if (conf->nr_strip_zones == 1) {
 132                 conf->layout = RAID0_ORIG_LAYOUT;
 133         } else if (mddev->layout == RAID0_ORIG_LAYOUT ||
 134                    mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) {
 135                 conf->layout = mddev->layout;
 136         } else if (default_layout == RAID0_ORIG_LAYOUT ||
 137                    default_layout == RAID0_ALT_MULTIZONE_LAYOUT) {
 138                 conf->layout = default_layout;
 139         } else {
 140                 pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n",
 141                        mdname(mddev));
 142                 pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n");
 143                 err = -ENOTSUPP;
 144                 goto abort;
 145         }
 146         /*
 147          * now since we have the hard sector sizes, we can make sure
 148          * chunk size is a multiple of that sector size
 149          */
 150         if ((mddev->chunk_sectors << 9) % blksize) {
 151                 pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n",
 152                         mdname(mddev),
 153                         mddev->chunk_sectors << 9, blksize);
 154                 err = -EINVAL;
 155                 goto abort;
 156         }
 157
 158         err = -ENOMEM;
 159         conf->strip_zone = kcalloc(conf->nr_strip_zones,
 160                                    sizeof(struct strip_zone),
 161                                    GFP_KERNEL);
 162         if (!conf->strip_zone)
 163                 goto abort;
 164         conf->devlist = kzalloc(array3_size(sizeof(struct md_rdev *),
 165                                             conf->nr_strip_zones,
 166                                             mddev->raid_disks),
 167                                 GFP_KERNEL);
 168         if (!conf->devlist)
 169                 goto abort;
 170
 171         /* The first zone must contain all devices, so here we check that
 172          * there is a proper alignment of slots to devices and find them all
 173          */
 174         zone = &conf->strip_zone[0];
 175         cnt = 0;
 176         smallest = NULL;
 177         dev = conf->devlist;
 178         err = -EINVAL;
 179         rdev_for_each(rdev1, mddev) {
 180                 int j = rdev1->raid_disk;
 181
 182                 if (mddev->level == 10) {
 183                         /* taking over a raid10-n2 array */
 184                         j /= 2;
 185                         rdev1->new_raid_disk = j;
 186                 }
 187
 188                 if (mddev->level == 1) {
 189                         /* taiking over a raid1 array-
 190                          * we have only one active disk
 191                          */
 192                         j = 0;
 193                         rdev1->new_raid_disk = j;
 194                 }
 195
 196                 if (j < 0) {
 197                         pr_warn("md/raid0:%s: remove inactive devices before converting to RAID0\n",
 198                                 mdname(mddev));
 199                         goto abort;
 200                 }
 201                 if (j >= mddev->raid_disks) {
 202                         pr_warn("md/raid0:%s: bad disk number %d - aborting!\n",
 203                                 mdname(mddev), j);
 204                         goto abort;
 205                 }
 206                 if (dev[j]) {
 207                         pr_warn("md/raid0:%s: multiple devices for %d - aborting!\n",
 208                                 mdname(mddev), j);
 209                         goto abort;
 210                 }
 211                 dev[j] = rdev1;
 212
 213                 if (!smallest || (rdev1->sectors < smallest->sectors))
 214                         smallest = rdev1;
 215                 cnt++;
 216         }
 217         if (cnt != mddev->raid_disks) {
 218                 pr_warn("md/raid0:%s: too few disks (%d of %d) - aborting!\n",
 219                         mdname(mddev), cnt, mddev->raid_disks);
 220                 goto abort;
 221         }
 222         zone->nb_dev = cnt;
 223         zone->zone_end = smallest->sectors * cnt;
 224
 225         curr_zone_end = zone->zone_end;
 226
 227         /* now do the other zones */
 228         for (i = 1; i < conf->nr_strip_zones; i++)
 229         {
 230                 int j;
 231
 232                 zone = conf->strip_zone + i;
 233                 dev = conf->devlist + i * mddev->raid_disks;
 234
 235                 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
 236                 zone->dev_start = smallest->sectors;
 237                 smallest = NULL;
 238                 c = 0;
 239
 240                 for (j=0; j<cnt; j++) {
 241                         rdev = conf->devlist[j];
 242                         if (rdev->sectors <= zone->dev_start) {
 243                                 pr_debug("md/raid0:%s: checking %s ... nope\n",
 244                                          mdname(mddev),
 245                                          bdevname(rdev->bdev, b));
 246                                 continue;
 247                         }
 248                         pr_debug("md/raid0:%s: checking %s ..."
 249                                  " contained as device %d\n",
 250                                  mdname(mddev),
 251                                  bdevname(rdev->bdev, b), c);
 252                         dev[c] = rdev;
 253                         c++;
 254                         if (!smallest || rdev->sectors < smallest->sectors) {
 255                                 smallest = rdev;
 256                                 pr_debug("md/raid0:%s:  (%llu) is smallest!.\n",
 257                                          mdname(mddev),
 258                                          (unsigned long long)rdev->sectors);
 259                         }
 260                 }
 261
 262                 zone->nb_dev = c;
 263                 sectors = (smallest->sectors - zone->dev_start) * c;
 264                 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
 265                          mdname(mddev),
 266                          zone->nb_dev, (unsigned long long)sectors);
 267
 268                 curr_zone_end += sectors;
 269                 zone->zone_end = curr_zone_end;
 270
 271                 pr_debug("md/raid0:%s: current zone start: %llu\n",
 272                          mdname(mddev),
 273                          (unsigned long long)smallest->sectors);
 274         }
 275
 276         pr_debug("md/raid0:%s: done.\n", mdname(mddev));
 277         *private_conf = conf;
 278
 279         return 0;
 280 abort:
 281         kfree(conf->strip_zone);
 282         kfree(conf->devlist);
 283         kfree(conf);
 284         *private_conf = ERR_PTR(err);
 285         return err;
 286 }
 287
 288 /* Find the zone which holds a particular offset
 289  * Update *sectorp to be an offset in that zone
 290  */
 291 static struct strip_zone *find_zone(struct r0conf *conf,
 292                                     sector_t *sectorp)
 293 {
 294         int i;
 295         struct strip_zone *z = conf->strip_zone;
 296         sector_t sector = *sectorp;
 297
 298         for (i = 0; i < conf->nr_strip_zones; i++)
 299                 if (sector < z[i].zone_end) {
 300                         if (i)
 301                                 *sectorp = sector - z[i-1].zone_end;
 302                         return z + i;
 303                 }
 304         BUG();
 305 }
 306
 307 /*
 308  * remaps the bio to the target device. we separate two flows.
 309  * power 2 flow and a general flow for the sake of performance
 310 */
 311 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
 312                                 sector_t sector, sector_t *sector_offset)
 313 {
 314         unsigned int sect_in_chunk;
 315         sector_t chunk;
 316         struct r0conf *conf = mddev->private;
 317         int raid_disks = conf->strip_zone[0].nb_dev;
 318         unsigned int chunk_sects = mddev->chunk_sectors;
 319
 320         if (is_power_of_2(chunk_sects)) {
 321                 int chunksect_bits = ffz(~chunk_sects);
 322                 /* find the sector offset inside the chunk */
 323                 sect_in_chunk  = sector & (chunk_sects - 1);
 324                 sector >>= chunksect_bits;
 325                 /* chunk in zone */
 326                 chunk = *sector_offset;
 327                 /* quotient is the chunk in real device*/
 328                 sector_div(chunk, zone->nb_dev << chunksect_bits);
 329         } else{
 330                 sect_in_chunk = sector_div(sector, chunk_sects);
 331                 chunk = *sector_offset;
 332                 sector_div(chunk, chunk_sects * zone->nb_dev);
 333         }
 334         /*
 335         *  position the bio over the real device
 336         *  real sector = chunk in device + starting of zone
 337         *       + the position in the chunk
 338         */
 339         *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
 340         return conf->devlist[(zone - conf->strip_zone)*raid_disks
 341                              + sector_div(sector, zone->nb_dev)];
 342 }
 343
 344 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
 345 {
 346         sector_t array_sectors = 0;
 347         struct md_rdev *rdev;
 348
 349         WARN_ONCE(sectors || raid_disks,
 350                   "%s does not support generic reshape\n", __func__);
 351
 352         rdev_for_each(rdev, mddev)
 353                 array_sectors += (rdev->sectors &
 354                                   ~(sector_t)(mddev->chunk_sectors-1));
 355
 356         return array_sectors;
 357 }
 358
 359 static void raid0_free(struct mddev *mddev, void *priv);
 360
 361 static int raid0_run(struct mddev *mddev)
 362 {
 363         struct r0conf *conf;
 364         int ret;
 365
 366         if (mddev->chunk_sectors == 0) {
 367                 pr_warn("md/raid0:%s: chunk size must be set.\n", mdname(mddev));
 368                 return -EINVAL;
 369         }
 370         if (md_check_no_bitmap(mddev))
 371                 return -EINVAL;
 372
 373         /* if private is not null, we are here after takeover */
 374         if (mddev->private == NULL) {
 375                 ret = create_strip_zones(mddev, &conf);
 376                 if (ret < 0)
 377                         return ret;
 378                 mddev->private = conf;
 379         }
 380         conf = mddev->private;
 381         if (mddev->queue) {
 382                 struct md_rdev *rdev;
 383                 bool discard_supported = false;
 384
 385                 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
 386                 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
 387                 blk_queue_max_write_zeroes_sectors(mddev->queue, mddev->chunk_sectors);
 388                 blk_queue_max_discard_sectors(mddev->queue, UINT_MAX);
 389
 390                 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
 391                 blk_queue_io_opt(mddev->queue,
 392                                  (mddev->chunk_sectors << 9) * mddev->raid_disks);
 393
 394                 rdev_for_each(rdev, mddev) {
 395                         disk_stack_limits(mddev->gendisk, rdev->bdev,
 396                                           rdev->data_offset << 9);
 397                         if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
 398                                 discard_supported = true;
 399                 }
 400                 if (!discard_supported)
 401                         blk_queue_flag_clear(QUEUE_FLAG_DISCARD, mddev->queue);
 402                 else
 403                         blk_queue_flag_set(QUEUE_FLAG_DISCARD, mddev->queue);
 404         }
 405
 406         /* calculate array device size */
 407         md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
 408
 409         pr_debug("md/raid0:%s: md_size is %llu sectors.\n",
 410                  mdname(mddev),
 411                  (unsigned long long)mddev->array_sectors);
 412
 413         dump_zones(mddev);
 414
 415         ret = md_integrity_register(mddev);
 416
 417         return ret;
 418 }
 419
 420 static void raid0_free(struct mddev *mddev, void *priv)
 421 {
 422         struct r0conf *conf = priv;
 423
 424         kfree(conf->strip_zone);
 425         kfree(conf->devlist);
 426         kfree(conf);
 427 }
 428
 429 static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
 430 {
 431         struct r0conf *conf = mddev->private;
 432         struct strip_zone *zone;
 433         sector_t start = bio->bi_iter.bi_sector;
 434         sector_t end;
 435         unsigned int stripe_size;
 436         sector_t first_stripe_index, last_stripe_index;
 437         sector_t start_disk_offset;
 438         unsigned int start_disk_index;
 439         sector_t end_disk_offset;
 440         unsigned int end_disk_index;
 441         unsigned int disk;
 442
 443         zone = find_zone(conf, &start);
 444
 445         if (bio_end_sector(bio) > zone->zone_end) {
 446                 struct bio *split = bio_split(bio,
 447                         zone->zone_end - bio->bi_iter.bi_sector, GFP_NOIO,
 448                         &mddev->bio_set);
 449                 bio_chain(split, bio);
 450                 submit_bio_noacct(bio);
 451                 bio = split;
 452                 end = zone->zone_end;
 453         } else
 454                 end = bio_end_sector(bio);
 455
 456         if (zone != conf->strip_zone)
 457                 end = end - zone[-1].zone_end;
 458
 459         /* Now start and end is the offset in zone */
 460         stripe_size = zone->nb_dev * mddev->chunk_sectors;
 461
 462         first_stripe_index = start;
 463         sector_div(first_stripe_index, stripe_size);
 464         last_stripe_index = end;
 465         sector_div(last_stripe_index, stripe_size);
 466
 467         start_disk_index = (int)(start - first_stripe_index * stripe_size) /
 468                 mddev->chunk_sectors;
 469         start_disk_offset = ((int)(start - first_stripe_index * stripe_size) %
 470                 mddev->chunk_sectors) +
 471                 first_stripe_index * mddev->chunk_sectors;
 472         end_disk_index = (int)(end - last_stripe_index * stripe_size) /
 473                 mddev->chunk_sectors;
 474         end_disk_offset = ((int)(end - last_stripe_index * stripe_size) %
 475                 mddev->chunk_sectors) +
 476                 last_stripe_index * mddev->chunk_sectors;
 477
 478         for (disk = 0; disk < zone->nb_dev; disk++) {
 479                 sector_t dev_start, dev_end;
 480                 struct bio *discard_bio = NULL;
 481                 struct md_rdev *rdev;
 482
 483                 if (disk < start_disk_index)
 484                         dev_start = (first_stripe_index + 1) *
 485                                 mddev->chunk_sectors;
 486                 else if (disk > start_disk_index)
 487                         dev_start = first_stripe_index * mddev->chunk_sectors;
 488                 else
 489                         dev_start = start_disk_offset;
 490
 491                 if (disk < end_disk_index)
 492                         dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;
 493                 else if (disk > end_disk_index)
 494                         dev_end = last_stripe_index * mddev->chunk_sectors;
 495                 else
 496                         dev_end = end_disk_offset;
 497
 498                 if (dev_end <= dev_start)
 499                         continue;
 500
 501                 rdev = conf->devlist[(zone - conf->strip_zone) *
 502                         conf->strip_zone[0].nb_dev + disk];
 503                 if (__blkdev_issue_discard(rdev->bdev,
 504                         dev_start + zone->dev_start + rdev->data_offset,
 505                         dev_end - dev_start, GFP_NOIO, 0, &discard_bio) ||
 506                     !discard_bio)
 507                         continue;
 508                 bio_chain(discard_bio, bio);
 509                 bio_clone_blkg_association(discard_bio, bio);
 510                 if (mddev->gendisk)
 511                         trace_block_bio_remap(discard_bio,
 512                                 disk_devt(mddev->gendisk),
 513                                 bio->bi_iter.bi_sector);
 514                 submit_bio_noacct(discard_bio);
 515         }
 516         bio_endio(bio);
 517 }
 518
 519 static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
 520 {
 521         struct r0conf *conf = mddev->private;
 522         struct strip_zone *zone;
 523         struct md_rdev *tmp_dev;
 524         sector_t bio_sector;
 525         sector_t sector;
 526         sector_t orig_sector;
 527         unsigned chunk_sects;
 528         unsigned sectors;
 529
 530         if (unlikely(bio->bi_opf & REQ_PREFLUSH)
 531             && md_flush_request(mddev, bio))
 532                 return true;
 533
 534         if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) {
 535                 raid0_handle_discard(mddev, bio);
 536                 return true;
 537         }
 538
 539         bio_sector = bio->bi_iter.bi_sector;
 540         sector = bio_sector;
 541         chunk_sects = mddev->chunk_sectors;
 542
 543         sectors = chunk_sects -
 544                 (likely(is_power_of_2(chunk_sects))
 545                  ? (sector & (chunk_sects-1))
 546                  : sector_div(sector, chunk_sects));
 547
 548         /* Restore due to sector_div */
 549         sector = bio_sector;
 550
 551         if (sectors < bio_sectors(bio)) {
 552                 struct bio *split = bio_split(bio, sectors, GFP_NOIO,
 553                                               &mddev->bio_set);
 554                 bio_chain(split, bio);
 555                 submit_bio_noacct(bio);
 556                 bio = split;
 557         }
 558
 559         orig_sector = sector;
 560         zone = find_zone(mddev->private, &sector);
 561         switch (conf->layout) {
 562         case RAID0_ORIG_LAYOUT:
 563                 tmp_dev = map_sector(mddev, zone, orig_sector, &sector);
 564                 break;
 565         case RAID0_ALT_MULTIZONE_LAYOUT:
 566                 tmp_dev = map_sector(mddev, zone, sector, &sector);
 567                 break;
 568         default:
 569                 WARN(1, "md/raid0:%s: Invalid layout\n", mdname(mddev));
 570                 bio_io_error(bio);
 571                 return true;
 572         }
 573
 574         if (unlikely(is_mddev_broken(tmp_dev, "raid0"))) {
 575                 bio_io_error(bio);
 576                 return true;
 577         }
 578
 579         bio_set_dev(bio, tmp_dev->bdev);
 580         bio->bi_iter.bi_sector = sector + zone->dev_start +
 581                 tmp_dev->data_offset;
 582
 583         if (mddev->gendisk)
 584                 trace_block_bio_remap(bio, disk_devt(mddev->gendisk),
 585                                       bio_sector);
 586         mddev_check_writesame(mddev, bio);
 587         mddev_check_write_zeroes(mddev, bio);
 588         submit_bio_noacct(bio);
 589         return true;
 590 }
 591
 592 static void raid0_status(struct seq_file *seq, struct mddev *mddev)
 593 {
 594         seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
 595         return;
 596 }
 597
 598 static void *raid0_takeover_raid45(struct mddev *mddev)
 599 {
 600         struct md_rdev *rdev;
 601         struct r0conf *priv_conf;
 602
 603         if (mddev->degraded != 1) {
 604                 pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
 605                         mdname(mddev),
 606                         mddev->degraded);
 607                 return ERR_PTR(-EINVAL);
 608         }
 609
 610         rdev_for_each(rdev, mddev) {
 611                 /* check slot number for a disk */
 612                 if (rdev->raid_disk == mddev->raid_disks-1) {
 613                         pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n",
 614                                 mdname(mddev));
 615                         return ERR_PTR(-EINVAL);
 616                 }
 617                 rdev->sectors = mddev->dev_sectors;
 618         }
 619
 620         /* Set new parameters */
 621         mddev->new_level = 0;
 622         mddev->new_layout = 0;
 623         mddev->new_chunk_sectors = mddev->chunk_sectors;
 624         mddev->raid_disks--;
 625         mddev->delta_disks = -1;
 626         /* make sure it will be not marked as dirty */
 627         mddev->recovery_cp = MaxSector;
 628         mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
 629
 630         create_strip_zones(mddev, &priv_conf);
 631
 632         return priv_conf;
 633 }
 634
 635 static void *raid0_takeover_raid10(struct mddev *mddev)
 636 {
 637         struct r0conf *priv_conf;
 638
 639         /* Check layout:
 640          *  - far_copies must be 1
 641          *  - near_copies must be 2
 642          *  - disks number must be even
 643          *  - all mirrors must be already degraded
 644          */
 645         if (mddev->layout != ((1 << 8) + 2)) {
 646                 pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n",
 647                         mdname(mddev),
 648                         mddev->layout);
 649                 return ERR_PTR(-EINVAL);
 650         }
 651         if (mddev->raid_disks & 1) {
 652                 pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n",
 653                         mdname(mddev));
 654                 return ERR_PTR(-EINVAL);
 655         }
 656         if (mddev->degraded != (mddev->raid_disks>>1)) {
 657                 pr_warn("md/raid0:%s: All mirrors must be already degraded!\n",
 658                         mdname(mddev));
 659                 return ERR_PTR(-EINVAL);
 660         }
 661
 662         /* Set new parameters */
 663         mddev->new_level = 0;
 664         mddev->new_layout = 0;
 665         mddev->new_chunk_sectors = mddev->chunk_sectors;
 666         mddev->delta_disks = - mddev->raid_disks / 2;
 667         mddev->raid_disks += mddev->delta_disks;
 668         mddev->degraded = 0;
 669         /* make sure it will be not marked as dirty */
 670         mddev->recovery_cp = MaxSector;
 671         mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
 672
 673         create_strip_zones(mddev, &priv_conf);
 674         return priv_conf;
 675 }
 676
 677 static void *raid0_takeover_raid1(struct mddev *mddev)
 678 {
 679         struct r0conf *priv_conf;
 680         int chunksect;
 681
 682         /* Check layout:
 683          *  - (N - 1) mirror drives must be already faulty
 684          */
 685         if ((mddev->raid_disks - 1) != mddev->degraded) {
 686                 pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
 687                        mdname(mddev));
 688                 return ERR_PTR(-EINVAL);
 689         }
 690
 691         /*
 692          * a raid1 doesn't have the notion of chunk size, so
 693          * figure out the largest suitable size we can use.
 694          */
 695         chunksect = 64 * 2; /* 64K by default */
 696
 697         /* The array must be an exact multiple of chunksize */
 698         while (chunksect && (mddev->array_sectors & (chunksect - 1)))
 699                 chunksect >>= 1;
 700
 701         if ((chunksect << 9) < PAGE_SIZE)
 702                 /* array size does not allow a suitable chunk size */
 703                 return ERR_PTR(-EINVAL);
 704
 705         /* Set new parameters */
 706         mddev->new_level = 0;
 707         mddev->new_layout = 0;
 708         mddev->new_chunk_sectors = chunksect;
 709         mddev->chunk_sectors = chunksect;
 710         mddev->delta_disks = 1 - mddev->raid_disks;
 711         mddev->raid_disks = 1;
 712         /* make sure it will be not marked as dirty */
 713         mddev->recovery_cp = MaxSector;
 714         mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
 715
 716         create_strip_zones(mddev, &priv_conf);
 717         return priv_conf;
 718 }
 719
 720 static void *raid0_takeover(struct mddev *mddev)
 721 {
 722         /* raid0 can take over:
 723          *  raid4 - if all data disks are active.
 724          *  raid5 - providing it is Raid4 layout and one disk is faulty
 725          *  raid10 - assuming we have all necessary active disks
 726          *  raid1 - with (N -1) mirror drives faulty
 727          */
 728
 729         if (mddev->bitmap) {
 730                 pr_warn("md/raid0: %s: cannot takeover array with bitmap\n",
 731                         mdname(mddev));
 732                 return ERR_PTR(-EBUSY);
 733         }
 734         if (mddev->level == 4)
 735                 return raid0_takeover_raid45(mddev);
 736
 737         if (mddev->level == 5) {
 738                 if (mddev->layout == ALGORITHM_PARITY_N)
 739                         return raid0_takeover_raid45(mddev);
 740
 741                 pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
 742                         mdname(mddev), ALGORITHM_PARITY_N);
 743         }
 744
 745         if (mddev->level == 10)
 746                 return raid0_takeover_raid10(mddev);
 747
 748         if (mddev->level == 1)
 749                 return raid0_takeover_raid1(mddev);
 750
 751         pr_warn("Takeover from raid%i to raid0 not supported\n",
 752                 mddev->level);
 753
 754         return ERR_PTR(-EINVAL);
 755 }
 756
 757 static void raid0_quiesce(struct mddev *mddev, int quiesce)
 758 {
 759 }
 760
 761 static struct md_personality raid0_personality=
 762 {
 763         .name           = "raid0",
 764         .level          = 0,
 765         .owner          = THIS_MODULE,
 766         .make_request   = raid0_make_request,
 767         .run            = raid0_run,
 768         .free           = raid0_free,
 769         .status         = raid0_status,
 770         .size           = raid0_size,
 771         .takeover       = raid0_takeover,
 772         .quiesce        = raid0_quiesce,
 773 };
 774
 775 static int __init raid0_init (void)
 776 {
 777         return register_md_personality (&raid0_personality);
 778 }
 779
 780 static void raid0_exit (void)
 781 {
 782         unregister_md_personality (&raid0_personality);
 783 }
 784
 785 module_init(raid0_init);
 786 module_exit(raid0_exit);
 787 MODULE_LICENSE("GPL");
 788 MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
 789 MODULE_ALIAS("md-personality-2"); /* RAID0 */
 790 MODULE_ALIAS("md-raid0");
 791 MODULE_ALIAS("md-level-0");