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