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 if (mddev->queue) { 414 /* calculate the max read-ahead size. 415 * For read-ahead of large files to be effective, we need to 416 * readahead at least twice a whole stripe. i.e. number of devices 417 * multiplied by chunk size times 2. 418 * If an individual device has an ra_pages greater than the 419 * chunk size, then we will not drive that device as hard as it 420 * wants. We consider this a configuration error: a larger 421 * chunksize should be used in that case. 422 */ 423 int stripe = mddev->raid_disks * 424 (mddev->chunk_sectors << 9) / PAGE_SIZE; 425 if (mddev->queue->backing_dev_info->ra_pages < 2* stripe) 426 mddev->queue->backing_dev_info->ra_pages = 2* stripe; 427 } 428 429 dump_zones(mddev); 430 431 ret = md_integrity_register(mddev); 432 433 return ret; 434 } 435 436 static void raid0_free(struct mddev *mddev, void *priv) 437 { 438 struct r0conf *conf = priv; 439 440 kfree(conf->strip_zone); 441 kfree(conf->devlist); 442 kfree(conf); 443 } 444 445 /* 446 * Is io distribute over 1 or more chunks ? 447 */ 448 static inline int is_io_in_chunk_boundary(struct mddev *mddev, 449 unsigned int chunk_sects, struct bio *bio) 450 { 451 if (likely(is_power_of_2(chunk_sects))) { 452 return chunk_sects >= 453 ((bio->bi_iter.bi_sector & (chunk_sects-1)) 454 + bio_sectors(bio)); 455 } else{ 456 sector_t sector = bio->bi_iter.bi_sector; 457 return chunk_sects >= (sector_div(sector, chunk_sects) 458 + bio_sectors(bio)); 459 } 460 } 461 462 static void raid0_handle_discard(struct mddev *mddev, struct bio *bio) 463 { 464 struct r0conf *conf = mddev->private; 465 struct strip_zone *zone; 466 sector_t start = bio->bi_iter.bi_sector; 467 sector_t end; 468 unsigned int stripe_size; 469 sector_t first_stripe_index, last_stripe_index; 470 sector_t start_disk_offset; 471 unsigned int start_disk_index; 472 sector_t end_disk_offset; 473 unsigned int end_disk_index; 474 unsigned int disk; 475 476 zone = find_zone(conf, &start); 477 478 if (bio_end_sector(bio) > zone->zone_end) { 479 struct bio *split = bio_split(bio, 480 zone->zone_end - bio->bi_iter.bi_sector, GFP_NOIO, 481 &mddev->bio_set); 482 bio_chain(split, bio); 483 submit_bio_noacct(bio); 484 bio = split; 485 end = zone->zone_end; 486 } else 487 end = bio_end_sector(bio); 488 489 if (zone != conf->strip_zone) 490 end = end - zone[-1].zone_end; 491 492 /* Now start and end is the offset in zone */ 493 stripe_size = zone->nb_dev * mddev->chunk_sectors; 494 495 first_stripe_index = start; 496 sector_div(first_stripe_index, stripe_size); 497 last_stripe_index = end; 498 sector_div(last_stripe_index, stripe_size); 499 500 start_disk_index = (int)(start - first_stripe_index * stripe_size) / 501 mddev->chunk_sectors; 502 start_disk_offset = ((int)(start - first_stripe_index * stripe_size) % 503 mddev->chunk_sectors) + 504 first_stripe_index * mddev->chunk_sectors; 505 end_disk_index = (int)(end - last_stripe_index * stripe_size) / 506 mddev->chunk_sectors; 507 end_disk_offset = ((int)(end - last_stripe_index * stripe_size) % 508 mddev->chunk_sectors) + 509 last_stripe_index * mddev->chunk_sectors; 510 511 for (disk = 0; disk < zone->nb_dev; disk++) { 512 sector_t dev_start, dev_end; 513 struct bio *discard_bio = NULL; 514 struct md_rdev *rdev; 515 516 if (disk < start_disk_index) 517 dev_start = (first_stripe_index + 1) * 518 mddev->chunk_sectors; 519 else if (disk > start_disk_index) 520 dev_start = first_stripe_index * mddev->chunk_sectors; 521 else 522 dev_start = start_disk_offset; 523 524 if (disk < end_disk_index) 525 dev_end = (last_stripe_index + 1) * mddev->chunk_sectors; 526 else if (disk > end_disk_index) 527 dev_end = last_stripe_index * mddev->chunk_sectors; 528 else 529 dev_end = end_disk_offset; 530 531 if (dev_end <= dev_start) 532 continue; 533 534 rdev = conf->devlist[(zone - conf->strip_zone) * 535 conf->strip_zone[0].nb_dev + disk]; 536 if (__blkdev_issue_discard(rdev->bdev, 537 dev_start + zone->dev_start + rdev->data_offset, 538 dev_end - dev_start, GFP_NOIO, 0, &discard_bio) || 539 !discard_bio) 540 continue; 541 bio_chain(discard_bio, bio); 542 bio_clone_blkg_association(discard_bio, bio); 543 if (mddev->gendisk) 544 trace_block_bio_remap(bdev_get_queue(rdev->bdev), 545 discard_bio, disk_devt(mddev->gendisk), 546 bio->bi_iter.bi_sector); 547 submit_bio_noacct(discard_bio); 548 } 549 bio_endio(bio); 550 } 551 552 static bool raid0_make_request(struct mddev *mddev, struct bio *bio) 553 { 554 struct r0conf *conf = mddev->private; 555 struct strip_zone *zone; 556 struct md_rdev *tmp_dev; 557 sector_t bio_sector; 558 sector_t sector; 559 sector_t orig_sector; 560 unsigned chunk_sects; 561 unsigned sectors; 562 563 if (unlikely(bio->bi_opf & REQ_PREFLUSH) 564 && md_flush_request(mddev, bio)) 565 return true; 566 567 if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) { 568 raid0_handle_discard(mddev, bio); 569 return true; 570 } 571 572 bio_sector = bio->bi_iter.bi_sector; 573 sector = bio_sector; 574 chunk_sects = mddev->chunk_sectors; 575 576 sectors = chunk_sects - 577 (likely(is_power_of_2(chunk_sects)) 578 ? (sector & (chunk_sects-1)) 579 : sector_div(sector, chunk_sects)); 580 581 /* Restore due to sector_div */ 582 sector = bio_sector; 583 584 if (sectors < bio_sectors(bio)) { 585 struct bio *split = bio_split(bio, sectors, GFP_NOIO, 586 &mddev->bio_set); 587 bio_chain(split, bio); 588 submit_bio_noacct(bio); 589 bio = split; 590 } 591 592 orig_sector = sector; 593 zone = find_zone(mddev->private, §or); 594 switch (conf->layout) { 595 case RAID0_ORIG_LAYOUT: 596 tmp_dev = map_sector(mddev, zone, orig_sector, §or); 597 break; 598 case RAID0_ALT_MULTIZONE_LAYOUT: 599 tmp_dev = map_sector(mddev, zone, sector, §or); 600 break; 601 default: 602 WARN(1, "md/raid0:%s: Invalid layout\n", mdname(mddev)); 603 bio_io_error(bio); 604 return true; 605 } 606 607 if (unlikely(is_mddev_broken(tmp_dev, "raid0"))) { 608 bio_io_error(bio); 609 return true; 610 } 611 612 bio_set_dev(bio, tmp_dev->bdev); 613 bio->bi_iter.bi_sector = sector + zone->dev_start + 614 tmp_dev->data_offset; 615 616 if (mddev->gendisk) 617 trace_block_bio_remap(bio->bi_disk->queue, bio, 618 disk_devt(mddev->gendisk), bio_sector); 619 mddev_check_writesame(mddev, bio); 620 mddev_check_write_zeroes(mddev, bio); 621 submit_bio_noacct(bio); 622 return true; 623 } 624 625 static void raid0_status(struct seq_file *seq, struct mddev *mddev) 626 { 627 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2); 628 return; 629 } 630 631 static void *raid0_takeover_raid45(struct mddev *mddev) 632 { 633 struct md_rdev *rdev; 634 struct r0conf *priv_conf; 635 636 if (mddev->degraded != 1) { 637 pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n", 638 mdname(mddev), 639 mddev->degraded); 640 return ERR_PTR(-EINVAL); 641 } 642 643 rdev_for_each(rdev, mddev) { 644 /* check slot number for a disk */ 645 if (rdev->raid_disk == mddev->raid_disks-1) { 646 pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n", 647 mdname(mddev)); 648 return ERR_PTR(-EINVAL); 649 } 650 rdev->sectors = mddev->dev_sectors; 651 } 652 653 /* Set new parameters */ 654 mddev->new_level = 0; 655 mddev->new_layout = 0; 656 mddev->new_chunk_sectors = mddev->chunk_sectors; 657 mddev->raid_disks--; 658 mddev->delta_disks = -1; 659 /* make sure it will be not marked as dirty */ 660 mddev->recovery_cp = MaxSector; 661 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); 662 663 create_strip_zones(mddev, &priv_conf); 664 665 return priv_conf; 666 } 667 668 static void *raid0_takeover_raid10(struct mddev *mddev) 669 { 670 struct r0conf *priv_conf; 671 672 /* Check layout: 673 * - far_copies must be 1 674 * - near_copies must be 2 675 * - disks number must be even 676 * - all mirrors must be already degraded 677 */ 678 if (mddev->layout != ((1 << 8) + 2)) { 679 pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n", 680 mdname(mddev), 681 mddev->layout); 682 return ERR_PTR(-EINVAL); 683 } 684 if (mddev->raid_disks & 1) { 685 pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n", 686 mdname(mddev)); 687 return ERR_PTR(-EINVAL); 688 } 689 if (mddev->degraded != (mddev->raid_disks>>1)) { 690 pr_warn("md/raid0:%s: All mirrors must be already degraded!\n", 691 mdname(mddev)); 692 return ERR_PTR(-EINVAL); 693 } 694 695 /* Set new parameters */ 696 mddev->new_level = 0; 697 mddev->new_layout = 0; 698 mddev->new_chunk_sectors = mddev->chunk_sectors; 699 mddev->delta_disks = - mddev->raid_disks / 2; 700 mddev->raid_disks += mddev->delta_disks; 701 mddev->degraded = 0; 702 /* make sure it will be not marked as dirty */ 703 mddev->recovery_cp = MaxSector; 704 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); 705 706 create_strip_zones(mddev, &priv_conf); 707 return priv_conf; 708 } 709 710 static void *raid0_takeover_raid1(struct mddev *mddev) 711 { 712 struct r0conf *priv_conf; 713 int chunksect; 714 715 /* Check layout: 716 * - (N - 1) mirror drives must be already faulty 717 */ 718 if ((mddev->raid_disks - 1) != mddev->degraded) { 719 pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n", 720 mdname(mddev)); 721 return ERR_PTR(-EINVAL); 722 } 723 724 /* 725 * a raid1 doesn't have the notion of chunk size, so 726 * figure out the largest suitable size we can use. 727 */ 728 chunksect = 64 * 2; /* 64K by default */ 729 730 /* The array must be an exact multiple of chunksize */ 731 while (chunksect && (mddev->array_sectors & (chunksect - 1))) 732 chunksect >>= 1; 733 734 if ((chunksect << 9) < PAGE_SIZE) 735 /* array size does not allow a suitable chunk size */ 736 return ERR_PTR(-EINVAL); 737 738 /* Set new parameters */ 739 mddev->new_level = 0; 740 mddev->new_layout = 0; 741 mddev->new_chunk_sectors = chunksect; 742 mddev->chunk_sectors = chunksect; 743 mddev->delta_disks = 1 - mddev->raid_disks; 744 mddev->raid_disks = 1; 745 /* make sure it will be not marked as dirty */ 746 mddev->recovery_cp = MaxSector; 747 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); 748 749 create_strip_zones(mddev, &priv_conf); 750 return priv_conf; 751 } 752 753 static void *raid0_takeover(struct mddev *mddev) 754 { 755 /* raid0 can take over: 756 * raid4 - if all data disks are active. 757 * raid5 - providing it is Raid4 layout and one disk is faulty 758 * raid10 - assuming we have all necessary active disks 759 * raid1 - with (N -1) mirror drives faulty 760 */ 761 762 if (mddev->bitmap) { 763 pr_warn("md/raid0: %s: cannot takeover array with bitmap\n", 764 mdname(mddev)); 765 return ERR_PTR(-EBUSY); 766 } 767 if (mddev->level == 4) 768 return raid0_takeover_raid45(mddev); 769 770 if (mddev->level == 5) { 771 if (mddev->layout == ALGORITHM_PARITY_N) 772 return raid0_takeover_raid45(mddev); 773 774 pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n", 775 mdname(mddev), ALGORITHM_PARITY_N); 776 } 777 778 if (mddev->level == 10) 779 return raid0_takeover_raid10(mddev); 780 781 if (mddev->level == 1) 782 return raid0_takeover_raid1(mddev); 783 784 pr_warn("Takeover from raid%i to raid0 not supported\n", 785 mddev->level); 786 787 return ERR_PTR(-EINVAL); 788 } 789 790 static void raid0_quiesce(struct mddev *mddev, int quiesce) 791 { 792 } 793 794 static struct md_personality raid0_personality= 795 { 796 .name = "raid0", 797 .level = 0, 798 .owner = THIS_MODULE, 799 .make_request = raid0_make_request, 800 .run = raid0_run, 801 .free = raid0_free, 802 .status = raid0_status, 803 .size = raid0_size, 804 .takeover = raid0_takeover, 805 .quiesce = raid0_quiesce, 806 }; 807 808 static int __init raid0_init (void) 809 { 810 return register_md_personality (&raid0_personality); 811 } 812 813 static void raid0_exit (void) 814 { 815 unregister_md_personality (&raid0_personality); 816 } 817 818 module_init(raid0_init); 819 module_exit(raid0_exit); 820 MODULE_LICENSE("GPL"); 821 MODULE_DESCRIPTION("RAID0 (striping) personality for MD"); 822 MODULE_ALIAS("md-personality-2"); /* RAID0 */ 823 MODULE_ALIAS("md-raid0"); 824 MODULE_ALIAS("md-level-0"); 825