drivers/md/raid0.c

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This source file includes following definitions.
raid0_congested
dump_zones
create_strip_zones
find_zone
map_sector
raid0_size
raid0_run
raid0_free
is_io_in_chunk_boundary
raid0_handle_discard
raid0_make_request
raid0_status
raid0_takeover_raid45
raid0_takeover_raid10
raid0_takeover_raid1
raid0_takeover
raid0_quiesce
raid0_init
raid0_exit
   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 static int raid0_congested(struct mddev *mddev, int bits)
  33 {
  34         struct r0conf *conf = mddev->private;
  35         struct md_rdev **devlist = conf->devlist;
  36         int raid_disks = conf->strip_zone[0].nb_dev;
  37         int i, ret = 0;
  38 
  39         for (i = 0; i < raid_disks && !ret ; i++) {
  40                 struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
  41 
  42                 ret |= bdi_congested(q->backing_dev_info, bits);
  43         }
  44         return ret;
  45 }
  46 
  47 /*
  48  * inform the user of the raid configuration
  49 */
  50 static void dump_zones(struct mddev *mddev)
  51 {
  52         int j, k;
  53         sector_t zone_size = 0;
  54         sector_t zone_start = 0;
  55         char b[BDEVNAME_SIZE];
  56         struct r0conf *conf = mddev->private;
  57         int raid_disks = conf->strip_zone[0].nb_dev;
  58         pr_debug("md: RAID0 configuration for %s - %d zone%s\n",
  59                  mdname(mddev),
  60                  conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s");
  61         for (j = 0; j < conf->nr_strip_zones; j++) {
  62                 char line[200];
  63                 int len = 0;
  64 
  65                 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
  66                         len += snprintf(line+len, 200-len, "%s%s", k?"/":"",
  67                                         bdevname(conf->devlist[j*raid_disks
  68                                                                + k]->bdev, b));
  69                 pr_debug("md: zone%d=[%s]\n", j, line);
  70 
  71                 zone_size  = conf->strip_zone[j].zone_end - zone_start;
  72                 pr_debug("      zone-offset=%10lluKB, device-offset=%10lluKB, size=%10lluKB\n",
  73                         (unsigned long long)zone_start>>1,
  74                         (unsigned long long)conf->strip_zone[j].dev_start>>1,
  75                         (unsigned long long)zone_size>>1);
  76                 zone_start = conf->strip_zone[j].zone_end;
  77         }
  78 }
  79 
  80 static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
  81 {
  82         int i, c, err;
  83         sector_t curr_zone_end, sectors;
  84         struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
  85         struct strip_zone *zone;
  86         int cnt;
  87         char b[BDEVNAME_SIZE];
  88         char b2[BDEVNAME_SIZE];
  89         struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
  90         unsigned blksize = 512;
  91 
  92         *private_conf = ERR_PTR(-ENOMEM);
  93         if (!conf)
  94                 return -ENOMEM;
  95         rdev_for_each(rdev1, mddev) {
  96                 pr_debug("md/raid0:%s: looking at %s\n",
  97                          mdname(mddev),
  98                          bdevname(rdev1->bdev, b));
  99                 c = 0;
 100 
 101                 /* round size to chunk_size */
 102                 sectors = rdev1->sectors;
 103                 sector_div(sectors, mddev->chunk_sectors);
 104                 rdev1->sectors = sectors * mddev->chunk_sectors;
 105 
 106                 blksize = max(blksize, queue_logical_block_size(
 107                                       rdev1->bdev->bd_disk->queue));
 108 
 109                 rdev_for_each(rdev2, mddev) {
 110                         pr_debug("md/raid0:%s:   comparing %s(%llu)"
 111                                  " with %s(%llu)\n",
 112                                  mdname(mddev),
 113                                  bdevname(rdev1->bdev,b),
 114                                  (unsigned long long)rdev1->sectors,
 115                                  bdevname(rdev2->bdev,b2),
 116                                  (unsigned long long)rdev2->sectors);
 117                         if (rdev2 == rdev1) {
 118                                 pr_debug("md/raid0:%s:   END\n",
 119                                          mdname(mddev));
 120                                 break;
 121                         }
 122                         if (rdev2->sectors == rdev1->sectors) {
 123                                 /*
 124                                  * Not unique, don't count it as a new
 125                                  * group
 126                                  */
 127                                 pr_debug("md/raid0:%s:   EQUAL\n",
 128                                          mdname(mddev));
 129                                 c = 1;
 130                                 break;
 131                         }
 132                         pr_debug("md/raid0:%s:   NOT EQUAL\n",
 133                                  mdname(mddev));
 134                 }
 135                 if (!c) {
 136                         pr_debug("md/raid0:%s:   ==> UNIQUE\n",
 137                                  mdname(mddev));
 138                         conf->nr_strip_zones++;
 139                         pr_debug("md/raid0:%s: %d zones\n",
 140                                  mdname(mddev), conf->nr_strip_zones);
 141                 }
 142         }
 143         pr_debug("md/raid0:%s: FINAL %d zones\n",
 144                  mdname(mddev), conf->nr_strip_zones);
 145 
 146         if (conf->nr_strip_zones == 1) {
 147                 conf->layout = RAID0_ORIG_LAYOUT;
 148         } else if (mddev->layout == RAID0_ORIG_LAYOUT ||
 149                    mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) {
 150                 conf->layout = mddev->layout;
 151         } else if (default_layout == RAID0_ORIG_LAYOUT ||
 152                    default_layout == RAID0_ALT_MULTIZONE_LAYOUT) {
 153                 conf->layout = default_layout;
 154         } else {
 155                 pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n",
 156                        mdname(mddev));
 157                 pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n");
 158                 err = -ENOTSUPP;
 159                 goto abort;
 160         }
 161         /*
 162          * now since we have the hard sector sizes, we can make sure
 163          * chunk size is a multiple of that sector size
 164          */
 165         if ((mddev->chunk_sectors << 9) % blksize) {
 166                 pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n",
 167                         mdname(mddev),
 168                         mddev->chunk_sectors << 9, blksize);
 169                 err = -EINVAL;
 170                 goto abort;
 171         }
 172 
 173         err = -ENOMEM;
 174         conf->strip_zone = kcalloc(conf->nr_strip_zones,
 175                                    sizeof(struct strip_zone),
 176                                    GFP_KERNEL);
 177         if (!conf->strip_zone)
 178                 goto abort;
 179         conf->devlist = kzalloc(array3_size(sizeof(struct md_rdev *),
 180                                             conf->nr_strip_zones,
 181                                             mddev->raid_disks),
 182                                 GFP_KERNEL);
 183         if (!conf->devlist)
 184                 goto abort;
 185 
 186         /* The first zone must contain all devices, so here we check that
 187          * there is a proper alignment of slots to devices and find them all
 188          */
 189         zone = &conf->strip_zone[0];
 190         cnt = 0;
 191         smallest = NULL;
 192         dev = conf->devlist;
 193         err = -EINVAL;
 194         rdev_for_each(rdev1, mddev) {
 195                 int j = rdev1->raid_disk;
 196 
 197                 if (mddev->level == 10) {
 198                         /* taking over a raid10-n2 array */
 199                         j /= 2;
 200                         rdev1->new_raid_disk = j;
 201                 }
 202 
 203                 if (mddev->level == 1) {
 204                         /* taiking over a raid1 array-
 205                          * we have only one active disk
 206                          */
 207                         j = 0;
 208                         rdev1->new_raid_disk = j;
 209                 }
 210 
 211                 if (j < 0) {
 212                         pr_warn("md/raid0:%s: remove inactive devices before converting to RAID0\n",
 213                                 mdname(mddev));
 214                         goto abort;
 215                 }
 216                 if (j >= mddev->raid_disks) {
 217                         pr_warn("md/raid0:%s: bad disk number %d - aborting!\n",
 218                                 mdname(mddev), j);
 219                         goto abort;
 220                 }
 221                 if (dev[j]) {
 222                         pr_warn("md/raid0:%s: multiple devices for %d - aborting!\n",
 223                                 mdname(mddev), j);
 224                         goto abort;
 225                 }
 226                 dev[j] = rdev1;
 227 
 228                 if (!smallest || (rdev1->sectors < smallest->sectors))
 229                         smallest = rdev1;
 230                 cnt++;
 231         }
 232         if (cnt != mddev->raid_disks) {
 233                 pr_warn("md/raid0:%s: too few disks (%d of %d) - aborting!\n",
 234                         mdname(mddev), cnt, mddev->raid_disks);
 235                 goto abort;
 236         }
 237         zone->nb_dev = cnt;
 238         zone->zone_end = smallest->sectors * cnt;
 239 
 240         curr_zone_end = zone->zone_end;
 241 
 242         /* now do the other zones */
 243         for (i = 1; i < conf->nr_strip_zones; i++)
 244         {
 245                 int j;
 246 
 247                 zone = conf->strip_zone + i;
 248                 dev = conf->devlist + i * mddev->raid_disks;
 249 
 250                 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
 251                 zone->dev_start = smallest->sectors;
 252                 smallest = NULL;
 253                 c = 0;
 254 
 255                 for (j=0; j<cnt; j++) {
 256                         rdev = conf->devlist[j];
 257                         if (rdev->sectors <= zone->dev_start) {
 258                                 pr_debug("md/raid0:%s: checking %s ... nope\n",
 259                                          mdname(mddev),
 260                                          bdevname(rdev->bdev, b));
 261                                 continue;
 262                         }
 263                         pr_debug("md/raid0:%s: checking %s ..."
 264                                  " contained as device %d\n",
 265                                  mdname(mddev),
 266                                  bdevname(rdev->bdev, b), c);
 267                         dev[c] = rdev;
 268                         c++;
 269                         if (!smallest || rdev->sectors < smallest->sectors) {
 270                                 smallest = rdev;
 271                                 pr_debug("md/raid0:%s:  (%llu) is smallest!.\n",
 272                                          mdname(mddev),
 273                                          (unsigned long long)rdev->sectors);
 274                         }
 275                 }
 276 
 277                 zone->nb_dev = c;
 278                 sectors = (smallest->sectors - zone->dev_start) * c;
 279                 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
 280                          mdname(mddev),
 281                          zone->nb_dev, (unsigned long long)sectors);
 282 
 283                 curr_zone_end += sectors;
 284                 zone->zone_end = curr_zone_end;
 285 
 286                 pr_debug("md/raid0:%s: current zone start: %llu\n",
 287                          mdname(mddev),
 288                          (unsigned long long)smallest->sectors);
 289         }
 290 
 291         pr_debug("md/raid0:%s: done.\n", mdname(mddev));
 292         *private_conf = conf;
 293 
 294         return 0;
 295 abort:
 296         kfree(conf->strip_zone);
 297         kfree(conf->devlist);
 298         kfree(conf);
 299         *private_conf = ERR_PTR(err);
 300         return err;
 301 }
 302 
 303 /* Find the zone which holds a particular offset
 304  * Update *sectorp to be an offset in that zone
 305  */
 306 static struct strip_zone *find_zone(struct r0conf *conf,
 307                                     sector_t *sectorp)
 308 {
 309         int i;
 310         struct strip_zone *z = conf->strip_zone;
 311         sector_t sector = *sectorp;
 312 
 313         for (i = 0; i < conf->nr_strip_zones; i++)
 314                 if (sector < z[i].zone_end) {
 315                         if (i)
 316                                 *sectorp = sector - z[i-1].zone_end;
 317                         return z + i;
 318                 }
 319         BUG();
 320 }
 321 
 322 /*
 323  * remaps the bio to the target device. we separate two flows.
 324  * power 2 flow and a general flow for the sake of performance
 325 */
 326 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
 327                                 sector_t sector, sector_t *sector_offset)
 328 {
 329         unsigned int sect_in_chunk;
 330         sector_t chunk;
 331         struct r0conf *conf = mddev->private;
 332         int raid_disks = conf->strip_zone[0].nb_dev;
 333         unsigned int chunk_sects = mddev->chunk_sectors;
 334 
 335         if (is_power_of_2(chunk_sects)) {
 336                 int chunksect_bits = ffz(~chunk_sects);
 337                 /* find the sector offset inside the chunk */
 338                 sect_in_chunk  = sector & (chunk_sects - 1);
 339                 sector >>= chunksect_bits;
 340                 /* chunk in zone */
 341                 chunk = *sector_offset;
 342                 /* quotient is the chunk in real device*/
 343                 sector_div(chunk, zone->nb_dev << chunksect_bits);
 344         } else{
 345                 sect_in_chunk = sector_div(sector, chunk_sects);
 346                 chunk = *sector_offset;
 347                 sector_div(chunk, chunk_sects * zone->nb_dev);
 348         }
 349         /*
 350         *  position the bio over the real device
 351         *  real sector = chunk in device + starting of zone
 352         *       + the position in the chunk
 353         */
 354         *sector_offset = (chunk * chunk_sects) + sect_in_chunk;
 355         return conf->devlist[(zone - conf->strip_zone)*raid_disks
 356                              + sector_div(sector, zone->nb_dev)];
 357 }
 358 
 359 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
 360 {
 361         sector_t array_sectors = 0;
 362         struct md_rdev *rdev;
 363 
 364         WARN_ONCE(sectors || raid_disks,
 365                   "%s does not support generic reshape\n", __func__);
 366 
 367         rdev_for_each(rdev, mddev)
 368                 array_sectors += (rdev->sectors &
 369                                   ~(sector_t)(mddev->chunk_sectors-1));
 370 
 371         return array_sectors;
 372 }
 373 
 374 static void raid0_free(struct mddev *mddev, void *priv);
 375 
 376 static int raid0_run(struct mddev *mddev)
 377 {
 378         struct r0conf *conf;
 379         int ret;
 380 
 381         if (mddev->chunk_sectors == 0) {
 382                 pr_warn("md/raid0:%s: chunk size must be set.\n", mdname(mddev));
 383                 return -EINVAL;
 384         }
 385         if (md_check_no_bitmap(mddev))
 386                 return -EINVAL;
 387 
 388         /* if private is not null, we are here after takeover */
 389         if (mddev->private == NULL) {
 390                 ret = create_strip_zones(mddev, &conf);
 391                 if (ret < 0)
 392                         return ret;
 393                 mddev->private = conf;
 394         }
 395         conf = mddev->private;
 396         if (mddev->queue) {
 397                 struct md_rdev *rdev;
 398                 bool discard_supported = false;
 399 
 400                 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
 401                 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
 402                 blk_queue_max_write_zeroes_sectors(mddev->queue, mddev->chunk_sectors);
 403                 blk_queue_max_discard_sectors(mddev->queue, UINT_MAX);
 404 
 405                 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
 406                 blk_queue_io_opt(mddev->queue,
 407                                  (mddev->chunk_sectors << 9) * mddev->raid_disks);
 408 
 409                 rdev_for_each(rdev, mddev) {
 410                         disk_stack_limits(mddev->gendisk, rdev->bdev,
 411                                           rdev->data_offset << 9);
 412                         if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
 413                                 discard_supported = true;
 414                 }
 415                 if (!discard_supported)
 416                         blk_queue_flag_clear(QUEUE_FLAG_DISCARD, mddev->queue);
 417                 else
 418                         blk_queue_flag_set(QUEUE_FLAG_DISCARD, mddev->queue);
 419         }
 420 
 421         /* calculate array device size */
 422         md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
 423 
 424         pr_debug("md/raid0:%s: md_size is %llu sectors.\n",
 425                  mdname(mddev),
 426                  (unsigned long long)mddev->array_sectors);
 427 
 428         if (mddev->queue) {
 429                 /* calculate the max read-ahead size.
 430                  * For read-ahead of large files to be effective, we need to
 431                  * readahead at least twice a whole stripe. i.e. number of devices
 432                  * multiplied by chunk size times 2.
 433                  * If an individual device has an ra_pages greater than the
 434                  * chunk size, then we will not drive that device as hard as it
 435                  * wants.  We consider this a configuration error: a larger
 436                  * chunksize should be used in that case.
 437                  */
 438                 int stripe = mddev->raid_disks *
 439                         (mddev->chunk_sectors << 9) / PAGE_SIZE;
 440                 if (mddev->queue->backing_dev_info->ra_pages < 2* stripe)
 441                         mddev->queue->backing_dev_info->ra_pages = 2* stripe;
 442         }
 443 
 444         dump_zones(mddev);
 445 
 446         ret = md_integrity_register(mddev);
 447 
 448         return ret;
 449 }
 450 
 451 static void raid0_free(struct mddev *mddev, void *priv)
 452 {
 453         struct r0conf *conf = priv;
 454 
 455         kfree(conf->strip_zone);
 456         kfree(conf->devlist);
 457         kfree(conf);
 458 }
 459 
 460 /*
 461  * Is io distribute over 1 or more chunks ?
 462 */
 463 static inline int is_io_in_chunk_boundary(struct mddev *mddev,
 464                         unsigned int chunk_sects, struct bio *bio)
 465 {
 466         if (likely(is_power_of_2(chunk_sects))) {
 467                 return chunk_sects >=
 468                         ((bio->bi_iter.bi_sector & (chunk_sects-1))
 469                                         + bio_sectors(bio));
 470         } else{
 471                 sector_t sector = bio->bi_iter.bi_sector;
 472                 return chunk_sects >= (sector_div(sector, chunk_sects)
 473                                                 + bio_sectors(bio));
 474         }
 475 }
 476 
 477 static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
 478 {
 479         struct r0conf *conf = mddev->private;
 480         struct strip_zone *zone;
 481         sector_t start = bio->bi_iter.bi_sector;
 482         sector_t end;
 483         unsigned int stripe_size;
 484         sector_t first_stripe_index, last_stripe_index;
 485         sector_t start_disk_offset;
 486         unsigned int start_disk_index;
 487         sector_t end_disk_offset;
 488         unsigned int end_disk_index;
 489         unsigned int disk;
 490 
 491         zone = find_zone(conf, &start);
 492 
 493         if (bio_end_sector(bio) > zone->zone_end) {
 494                 struct bio *split = bio_split(bio,
 495                         zone->zone_end - bio->bi_iter.bi_sector, GFP_NOIO,
 496                         &mddev->bio_set);
 497                 bio_chain(split, bio);
 498                 generic_make_request(bio);
 499                 bio = split;
 500                 end = zone->zone_end;
 501         } else
 502                 end = bio_end_sector(bio);
 503 
 504         if (zone != conf->strip_zone)
 505                 end = end - zone[-1].zone_end;
 506 
 507         /* Now start and end is the offset in zone */
 508         stripe_size = zone->nb_dev * mddev->chunk_sectors;
 509 
 510         first_stripe_index = start;
 511         sector_div(first_stripe_index, stripe_size);
 512         last_stripe_index = end;
 513         sector_div(last_stripe_index, stripe_size);
 514 
 515         start_disk_index = (int)(start - first_stripe_index * stripe_size) /
 516                 mddev->chunk_sectors;
 517         start_disk_offset = ((int)(start - first_stripe_index * stripe_size) %
 518                 mddev->chunk_sectors) +
 519                 first_stripe_index * mddev->chunk_sectors;
 520         end_disk_index = (int)(end - last_stripe_index * stripe_size) /
 521                 mddev->chunk_sectors;
 522         end_disk_offset = ((int)(end - last_stripe_index * stripe_size) %
 523                 mddev->chunk_sectors) +
 524                 last_stripe_index * mddev->chunk_sectors;
 525 
 526         for (disk = 0; disk < zone->nb_dev; disk++) {
 527                 sector_t dev_start, dev_end;
 528                 struct bio *discard_bio = NULL;
 529                 struct md_rdev *rdev;
 530 
 531                 if (disk < start_disk_index)
 532                         dev_start = (first_stripe_index + 1) *
 533                                 mddev->chunk_sectors;
 534                 else if (disk > start_disk_index)
 535                         dev_start = first_stripe_index * mddev->chunk_sectors;
 536                 else
 537                         dev_start = start_disk_offset;
 538 
 539                 if (disk < end_disk_index)
 540                         dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;
 541                 else if (disk > end_disk_index)
 542                         dev_end = last_stripe_index * mddev->chunk_sectors;
 543                 else
 544                         dev_end = end_disk_offset;
 545 
 546                 if (dev_end <= dev_start)
 547                         continue;
 548 
 549                 rdev = conf->devlist[(zone - conf->strip_zone) *
 550                         conf->strip_zone[0].nb_dev + disk];
 551                 if (__blkdev_issue_discard(rdev->bdev,
 552                         dev_start + zone->dev_start + rdev->data_offset,
 553                         dev_end - dev_start, GFP_NOIO, 0, &discard_bio) ||
 554                     !discard_bio)
 555                         continue;
 556                 bio_chain(discard_bio, bio);
 557                 bio_clone_blkg_association(discard_bio, bio);
 558                 if (mddev->gendisk)
 559                         trace_block_bio_remap(bdev_get_queue(rdev->bdev),
 560                                 discard_bio, disk_devt(mddev->gendisk),
 561                                 bio->bi_iter.bi_sector);
 562                 generic_make_request(discard_bio);
 563         }
 564         bio_endio(bio);
 565 }
 566 
 567 static bool raid0_make_request(struct mddev *mddev, struct bio *bio)
 568 {
 569         struct r0conf *conf = mddev->private;
 570         struct strip_zone *zone;
 571         struct md_rdev *tmp_dev;
 572         sector_t bio_sector;
 573         sector_t sector;
 574         sector_t orig_sector;
 575         unsigned chunk_sects;
 576         unsigned sectors;
 577 
 578         if (unlikely(bio->bi_opf & REQ_PREFLUSH)
 579             && md_flush_request(mddev, bio))
 580                 return true;
 581 
 582         if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) {
 583                 raid0_handle_discard(mddev, bio);
 584                 return true;
 585         }
 586 
 587         bio_sector = bio->bi_iter.bi_sector;
 588         sector = bio_sector;
 589         chunk_sects = mddev->chunk_sectors;
 590 
 591         sectors = chunk_sects -
 592                 (likely(is_power_of_2(chunk_sects))
 593                  ? (sector & (chunk_sects-1))
 594                  : sector_div(sector, chunk_sects));
 595 
 596         /* Restore due to sector_div */
 597         sector = bio_sector;
 598 
 599         if (sectors < bio_sectors(bio)) {
 600                 struct bio *split = bio_split(bio, sectors, GFP_NOIO,
 601                                               &mddev->bio_set);
 602                 bio_chain(split, bio);
 603                 generic_make_request(bio);
 604                 bio = split;
 605         }
 606 
 607         orig_sector = sector;
 608         zone = find_zone(mddev->private, &sector);
 609         switch (conf->layout) {
 610         case RAID0_ORIG_LAYOUT:
 611                 tmp_dev = map_sector(mddev, zone, orig_sector, &sector);
 612                 break;
 613         case RAID0_ALT_MULTIZONE_LAYOUT:
 614                 tmp_dev = map_sector(mddev, zone, sector, &sector);
 615                 break;
 616         default:
 617                 WARN(1, "md/raid0:%s: Invalid layout\n", mdname(mddev));
 618                 bio_io_error(bio);
 619                 return true;
 620         }
 621 
 622         if (unlikely(is_mddev_broken(tmp_dev, "raid0"))) {
 623                 bio_io_error(bio);
 624                 return true;
 625         }
 626 
 627         bio_set_dev(bio, tmp_dev->bdev);
 628         bio->bi_iter.bi_sector = sector + zone->dev_start +
 629                 tmp_dev->data_offset;
 630 
 631         if (mddev->gendisk)
 632                 trace_block_bio_remap(bio->bi_disk->queue, bio,
 633                                 disk_devt(mddev->gendisk), bio_sector);
 634         mddev_check_writesame(mddev, bio);
 635         mddev_check_write_zeroes(mddev, bio);
 636         generic_make_request(bio);
 637         return true;
 638 }
 639 
 640 static void raid0_status(struct seq_file *seq, struct mddev *mddev)
 641 {
 642         seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
 643         return;
 644 }
 645 
 646 static void *raid0_takeover_raid45(struct mddev *mddev)
 647 {
 648         struct md_rdev *rdev;
 649         struct r0conf *priv_conf;
 650 
 651         if (mddev->degraded != 1) {
 652                 pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
 653                         mdname(mddev),
 654                         mddev->degraded);
 655                 return ERR_PTR(-EINVAL);
 656         }
 657 
 658         rdev_for_each(rdev, mddev) {
 659                 /* check slot number for a disk */
 660                 if (rdev->raid_disk == mddev->raid_disks-1) {
 661                         pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n",
 662                                 mdname(mddev));
 663                         return ERR_PTR(-EINVAL);
 664                 }
 665                 rdev->sectors = mddev->dev_sectors;
 666         }
 667 
 668         /* Set new parameters */
 669         mddev->new_level = 0;
 670         mddev->new_layout = 0;
 671         mddev->new_chunk_sectors = mddev->chunk_sectors;
 672         mddev->raid_disks--;
 673         mddev->delta_disks = -1;
 674         /* make sure it will be not marked as dirty */
 675         mddev->recovery_cp = MaxSector;
 676         mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
 677 
 678         create_strip_zones(mddev, &priv_conf);
 679 
 680         return priv_conf;
 681 }
 682 
 683 static void *raid0_takeover_raid10(struct mddev *mddev)
 684 {
 685         struct r0conf *priv_conf;
 686 
 687         /* Check layout:
 688          *  - far_copies must be 1
 689          *  - near_copies must be 2
 690          *  - disks number must be even
 691          *  - all mirrors must be already degraded
 692          */
 693         if (mddev->layout != ((1 << 8) + 2)) {
 694                 pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n",
 695                         mdname(mddev),
 696                         mddev->layout);
 697                 return ERR_PTR(-EINVAL);
 698         }
 699         if (mddev->raid_disks & 1) {
 700                 pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n",
 701                         mdname(mddev));
 702                 return ERR_PTR(-EINVAL);
 703         }
 704         if (mddev->degraded != (mddev->raid_disks>>1)) {
 705                 pr_warn("md/raid0:%s: All mirrors must be already degraded!\n",
 706                         mdname(mddev));
 707                 return ERR_PTR(-EINVAL);
 708         }
 709 
 710         /* Set new parameters */
 711         mddev->new_level = 0;
 712         mddev->new_layout = 0;
 713         mddev->new_chunk_sectors = mddev->chunk_sectors;
 714         mddev->delta_disks = - mddev->raid_disks / 2;
 715         mddev->raid_disks += mddev->delta_disks;
 716         mddev->degraded = 0;
 717         /* make sure it will be not marked as dirty */
 718         mddev->recovery_cp = MaxSector;
 719         mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
 720 
 721         create_strip_zones(mddev, &priv_conf);
 722         return priv_conf;
 723 }
 724 
 725 static void *raid0_takeover_raid1(struct mddev *mddev)
 726 {
 727         struct r0conf *priv_conf;
 728         int chunksect;
 729 
 730         /* Check layout:
 731          *  - (N - 1) mirror drives must be already faulty
 732          */
 733         if ((mddev->raid_disks - 1) != mddev->degraded) {
 734                 pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
 735                        mdname(mddev));
 736                 return ERR_PTR(-EINVAL);
 737         }
 738 
 739         /*
 740          * a raid1 doesn't have the notion of chunk size, so
 741          * figure out the largest suitable size we can use.
 742          */
 743         chunksect = 64 * 2; /* 64K by default */
 744 
 745         /* The array must be an exact multiple of chunksize */
 746         while (chunksect && (mddev->array_sectors & (chunksect - 1)))
 747                 chunksect >>= 1;
 748 
 749         if ((chunksect << 9) < PAGE_SIZE)
 750                 /* array size does not allow a suitable chunk size */
 751                 return ERR_PTR(-EINVAL);
 752 
 753         /* Set new parameters */
 754         mddev->new_level = 0;
 755         mddev->new_layout = 0;
 756         mddev->new_chunk_sectors = chunksect;
 757         mddev->chunk_sectors = chunksect;
 758         mddev->delta_disks = 1 - mddev->raid_disks;
 759         mddev->raid_disks = 1;
 760         /* make sure it will be not marked as dirty */
 761         mddev->recovery_cp = MaxSector;
 762         mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
 763 
 764         create_strip_zones(mddev, &priv_conf);
 765         return priv_conf;
 766 }
 767 
 768 static void *raid0_takeover(struct mddev *mddev)
 769 {
 770         /* raid0 can take over:
 771          *  raid4 - if all data disks are active.
 772          *  raid5 - providing it is Raid4 layout and one disk is faulty
 773          *  raid10 - assuming we have all necessary active disks
 774          *  raid1 - with (N -1) mirror drives faulty
 775          */
 776 
 777         if (mddev->bitmap) {
 778                 pr_warn("md/raid0: %s: cannot takeover array with bitmap\n",
 779                         mdname(mddev));
 780                 return ERR_PTR(-EBUSY);
 781         }
 782         if (mddev->level == 4)
 783                 return raid0_takeover_raid45(mddev);
 784 
 785         if (mddev->level == 5) {
 786                 if (mddev->layout == ALGORITHM_PARITY_N)
 787                         return raid0_takeover_raid45(mddev);
 788 
 789                 pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
 790                         mdname(mddev), ALGORITHM_PARITY_N);
 791         }
 792 
 793         if (mddev->level == 10)
 794                 return raid0_takeover_raid10(mddev);
 795 
 796         if (mddev->level == 1)
 797                 return raid0_takeover_raid1(mddev);
 798 
 799         pr_warn("Takeover from raid%i to raid0 not supported\n",
 800                 mddev->level);
 801 
 802         return ERR_PTR(-EINVAL);
 803 }
 804 
 805 static void raid0_quiesce(struct mddev *mddev, int quiesce)
 806 {
 807 }
 808 
 809 static struct md_personality raid0_personality=
 810 {
 811         .name           = "raid0",
 812         .level          = 0,
 813         .owner          = THIS_MODULE,
 814         .make_request   = raid0_make_request,
 815         .run            = raid0_run,
 816         .free           = raid0_free,
 817         .status         = raid0_status,
 818         .size           = raid0_size,
 819         .takeover       = raid0_takeover,
 820         .quiesce        = raid0_quiesce,
 821         .congested      = raid0_congested,
 822 };
 823 
 824 static int __init raid0_init (void)
 825 {
 826         return register_md_personality (&raid0_personality);
 827 }
 828 
 829 static void raid0_exit (void)
 830 {
 831         unregister_md_personality (&raid0_personality);
 832 }
 833 
 834 module_init(raid0_init);
 835 module_exit(raid0_exit);
 836 MODULE_LICENSE("GPL");
 837 MODULE_DESCRIPTION("RAID0 (striping) personality for MD");
 838 MODULE_ALIAS("md-personality-2"); /* RAID0 */
 839 MODULE_ALIAS("md-raid0");
 840 MODULE_ALIAS("md-level-0");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/md/raid0.c

DEFINITIONS
