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 (1L << MD_FAILLAST_DEV) | \ 32 (1L << MD_SERIALIZE_POLICY)) 33 34 /* 35 * inform the user of the raid configuration 36 */ 37 static void dump_zones(struct mddev *mddev) 38 { 39 int j, k; 40 sector_t zone_size = 0; 41 sector_t zone_start = 0; 42 struct r0conf *conf = mddev->private; 43 int raid_disks = conf->strip_zone[0].nb_dev; 44 pr_debug("md: RAID0 configuration for %s - %d zone%s\n", 45 mdname(mddev), 46 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s"); 47 for (j = 0; j < conf->nr_strip_zones; j++) { 48 char line[200]; 49 int len = 0; 50 51 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 52 len += scnprintf(line+len, 200-len, "%s%pg", k?"/":"", 53 conf->devlist[j * raid_disks + k]->bdev); 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 struct r0conf *conf = kzalloc_obj(*conf, GFP_KERNEL); 73 unsigned int blksize = 512; 74 75 if (!mddev_is_dm(mddev)) 76 blksize = queue_logical_block_size(mddev->gendisk->queue); 77 78 *private_conf = ERR_PTR(-ENOMEM); 79 if (!conf) 80 return -ENOMEM; 81 rdev_for_each(rdev1, mddev) { 82 pr_debug("md/raid0:%s: looking at %pg\n", 83 mdname(mddev), 84 rdev1->bdev); 85 c = 0; 86 87 /* round size to chunk_size */ 88 sectors = rdev1->sectors; 89 sector_div(sectors, mddev->chunk_sectors); 90 rdev1->sectors = sectors * mddev->chunk_sectors; 91 92 if (mddev_is_dm(mddev)) 93 blksize = max(blksize, queue_logical_block_size( 94 rdev1->bdev->bd_disk->queue)); 95 96 rdev_for_each(rdev2, mddev) { 97 pr_debug("md/raid0:%s: comparing %pg(%llu)" 98 " with %pg(%llu)\n", 99 mdname(mddev), 100 rdev1->bdev, 101 (unsigned long long)rdev1->sectors, 102 rdev2->bdev, 103 (unsigned long long)rdev2->sectors); 104 if (rdev2 == rdev1) { 105 pr_debug("md/raid0:%s: END\n", 106 mdname(mddev)); 107 break; 108 } 109 if (rdev2->sectors == rdev1->sectors) { 110 /* 111 * Not unique, don't count it as a new 112 * group 113 */ 114 pr_debug("md/raid0:%s: EQUAL\n", 115 mdname(mddev)); 116 c = 1; 117 break; 118 } 119 pr_debug("md/raid0:%s: NOT EQUAL\n", 120 mdname(mddev)); 121 } 122 if (!c) { 123 pr_debug("md/raid0:%s: ==> UNIQUE\n", 124 mdname(mddev)); 125 conf->nr_strip_zones++; 126 pr_debug("md/raid0:%s: %d zones\n", 127 mdname(mddev), conf->nr_strip_zones); 128 } 129 } 130 pr_debug("md/raid0:%s: FINAL %d zones\n", 131 mdname(mddev), conf->nr_strip_zones); 132 133 /* 134 * now since we have the hard sector sizes, we can make sure 135 * chunk size is a multiple of that sector size 136 */ 137 if ((mddev->chunk_sectors << 9) % blksize) { 138 pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n", 139 mdname(mddev), 140 mddev->chunk_sectors << 9, blksize); 141 err = -EINVAL; 142 goto abort; 143 } 144 145 err = -ENOMEM; 146 conf->strip_zone = kzalloc_objs(struct strip_zone, conf->nr_strip_zones, 147 GFP_KERNEL); 148 if (!conf->strip_zone) 149 goto abort; 150 conf->devlist = kzalloc(array3_size(sizeof(struct md_rdev *), 151 conf->nr_strip_zones, 152 mddev->raid_disks), 153 GFP_KERNEL); 154 if (!conf->devlist) 155 goto abort; 156 157 /* The first zone must contain all devices, so here we check that 158 * there is a proper alignment of slots to devices and find them all 159 */ 160 zone = &conf->strip_zone[0]; 161 cnt = 0; 162 smallest = NULL; 163 dev = conf->devlist; 164 err = -EINVAL; 165 rdev_for_each(rdev1, mddev) { 166 int j = rdev1->raid_disk; 167 168 if (mddev->level == 10) { 169 /* taking over a raid10-n2 array */ 170 j /= 2; 171 rdev1->new_raid_disk = j; 172 } 173 174 if (mddev->level == 1) { 175 /* taiking over a raid1 array- 176 * we have only one active disk 177 */ 178 j = 0; 179 rdev1->new_raid_disk = j; 180 } 181 182 if (j < 0) { 183 pr_warn("md/raid0:%s: remove inactive devices before converting to RAID0\n", 184 mdname(mddev)); 185 goto abort; 186 } 187 if (j >= mddev->raid_disks) { 188 pr_warn("md/raid0:%s: bad disk number %d - aborting!\n", 189 mdname(mddev), j); 190 goto abort; 191 } 192 if (dev[j]) { 193 pr_warn("md/raid0:%s: multiple devices for %d - aborting!\n", 194 mdname(mddev), j); 195 goto abort; 196 } 197 dev[j] = rdev1; 198 199 if (!smallest || (rdev1->sectors < smallest->sectors)) 200 smallest = rdev1; 201 cnt++; 202 } 203 if (cnt != mddev->raid_disks) { 204 pr_warn("md/raid0:%s: too few disks (%d of %d) - aborting!\n", 205 mdname(mddev), cnt, mddev->raid_disks); 206 goto abort; 207 } 208 zone->nb_dev = cnt; 209 zone->zone_end = smallest->sectors * cnt; 210 211 curr_zone_end = zone->zone_end; 212 213 /* now do the other zones */ 214 for (i = 1; i < conf->nr_strip_zones; i++) 215 { 216 int j; 217 218 zone = conf->strip_zone + i; 219 dev = conf->devlist + i * mddev->raid_disks; 220 221 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i); 222 zone->dev_start = smallest->sectors; 223 smallest = NULL; 224 c = 0; 225 226 for (j=0; j<cnt; j++) { 227 rdev = conf->devlist[j]; 228 if (rdev->sectors <= zone->dev_start) { 229 pr_debug("md/raid0:%s: checking %pg ... nope\n", 230 mdname(mddev), 231 rdev->bdev); 232 continue; 233 } 234 pr_debug("md/raid0:%s: checking %pg ..." 235 " contained as device %d\n", 236 mdname(mddev), 237 rdev->bdev, c); 238 dev[c] = rdev; 239 c++; 240 if (!smallest || rdev->sectors < smallest->sectors) { 241 smallest = rdev; 242 pr_debug("md/raid0:%s: (%llu) is smallest!.\n", 243 mdname(mddev), 244 (unsigned long long)rdev->sectors); 245 } 246 } 247 248 zone->nb_dev = c; 249 sectors = (smallest->sectors - zone->dev_start) * c; 250 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n", 251 mdname(mddev), 252 zone->nb_dev, (unsigned long long)sectors); 253 254 curr_zone_end += sectors; 255 zone->zone_end = curr_zone_end; 256 257 pr_debug("md/raid0:%s: current zone start: %llu\n", 258 mdname(mddev), 259 (unsigned long long)smallest->sectors); 260 } 261 262 if (conf->nr_strip_zones == 1 || conf->strip_zone[1].nb_dev == 1) { 263 conf->layout = RAID0_ORIG_LAYOUT; 264 } else if (mddev->layout == RAID0_ORIG_LAYOUT || 265 mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) { 266 conf->layout = mddev->layout; 267 } else if (default_layout == RAID0_ORIG_LAYOUT || 268 default_layout == RAID0_ALT_MULTIZONE_LAYOUT) { 269 conf->layout = default_layout; 270 } else { 271 pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n", 272 mdname(mddev)); 273 pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n"); 274 err = -EOPNOTSUPP; 275 goto abort; 276 } 277 278 if (conf->layout == RAID0_ORIG_LAYOUT) { 279 for (i = 1; i < conf->nr_strip_zones; i++) { 280 sector_t first_sector = conf->strip_zone[i-1].zone_end; 281 282 sector_div(first_sector, mddev->chunk_sectors); 283 zone = conf->strip_zone + i; 284 /* disk_shift is first disk index used in the zone */ 285 zone->disk_shift = sector_div(first_sector, 286 zone->nb_dev); 287 } 288 } 289 290 pr_debug("md/raid0:%s: done.\n", mdname(mddev)); 291 *private_conf = conf; 292 293 return 0; 294 abort: 295 kfree(conf->strip_zone); 296 kfree(conf->devlist); 297 kfree(conf); 298 *private_conf = ERR_PTR(err); 299 return err; 300 } 301 302 /* Find the zone which holds a particular offset 303 * Update *sectorp to be an offset in that zone 304 */ 305 static struct strip_zone *find_zone(struct r0conf *conf, 306 sector_t *sectorp) 307 { 308 int i; 309 struct strip_zone *z = conf->strip_zone; 310 sector_t sector = *sectorp; 311 312 for (i = 0; i < conf->nr_strip_zones; i++) 313 if (sector < z[i].zone_end) { 314 if (i) 315 *sectorp = sector - z[i-1].zone_end; 316 return z + i; 317 } 318 BUG(); 319 } 320 321 /* 322 * remaps the bio to the target device. we separate two flows. 323 * power 2 flow and a general flow for the sake of performance 324 */ 325 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone, 326 sector_t sector, sector_t *sector_offset) 327 { 328 unsigned int sect_in_chunk; 329 sector_t chunk; 330 struct r0conf *conf = mddev->private; 331 int raid_disks = conf->strip_zone[0].nb_dev; 332 unsigned int chunk_sects = mddev->chunk_sectors; 333 334 if (is_power_of_2(chunk_sects)) { 335 int chunksect_bits = ffz(~chunk_sects); 336 /* find the sector offset inside the chunk */ 337 sect_in_chunk = sector & (chunk_sects - 1); 338 sector >>= chunksect_bits; 339 /* chunk in zone */ 340 chunk = *sector_offset; 341 /* quotient is the chunk in real device*/ 342 sector_div(chunk, zone->nb_dev << chunksect_bits); 343 } else{ 344 sect_in_chunk = sector_div(sector, chunk_sects); 345 chunk = *sector_offset; 346 sector_div(chunk, chunk_sects * zone->nb_dev); 347 } 348 /* 349 * position the bio over the real device 350 * real sector = chunk in device + starting of zone 351 * + the position in the chunk 352 */ 353 *sector_offset = (chunk * chunk_sects) + sect_in_chunk; 354 return conf->devlist[(zone - conf->strip_zone)*raid_disks 355 + sector_div(sector, zone->nb_dev)]; 356 } 357 358 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks) 359 { 360 sector_t array_sectors = 0; 361 struct md_rdev *rdev; 362 363 WARN_ONCE(sectors || raid_disks, 364 "%s does not support generic reshape\n", __func__); 365 366 rdev_for_each(rdev, mddev) 367 array_sectors += (rdev->sectors & 368 ~(sector_t)(mddev->chunk_sectors-1)); 369 370 return array_sectors; 371 } 372 373 static void raid0_free(struct mddev *mddev, void *priv) 374 { 375 struct r0conf *conf = priv; 376 377 kfree(conf->strip_zone); 378 kfree(conf->devlist); 379 kfree(conf); 380 } 381 382 static int raid0_set_limits(struct mddev *mddev) 383 { 384 struct queue_limits lim; 385 int err; 386 387 md_init_stacking_limits(&lim); 388 lim.max_hw_sectors = mddev->chunk_sectors; 389 lim.max_write_zeroes_sectors = mddev->chunk_sectors; 390 lim.max_hw_wzeroes_unmap_sectors = mddev->chunk_sectors; 391 lim.logical_block_size = mddev->logical_block_size; 392 lim.io_min = mddev->chunk_sectors << 9; 393 lim.io_opt = lim.io_min * mddev->raid_disks; 394 lim.chunk_sectors = mddev->chunk_sectors; 395 lim.features |= BLK_FEAT_ATOMIC_WRITES; 396 err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY); 397 if (err) 398 return err; 399 return queue_limits_set(mddev->gendisk->queue, &lim); 400 } 401 402 static int raid0_run(struct mddev *mddev) 403 { 404 struct r0conf *conf; 405 int ret; 406 407 if (mddev->chunk_sectors == 0) { 408 pr_warn("md/raid0:%s: chunk size must be set.\n", mdname(mddev)); 409 return -EINVAL; 410 } 411 if (md_check_no_bitmap(mddev)) 412 return -EINVAL; 413 414 if (!mddev_is_dm(mddev)) { 415 ret = raid0_set_limits(mddev); 416 if (ret) 417 return ret; 418 } 419 420 /* if private is not null, we are here after takeover */ 421 if (mddev->private == NULL) { 422 ret = create_strip_zones(mddev, &conf); 423 if (ret < 0) 424 return ret; 425 mddev->private = conf; 426 } 427 conf = mddev->private; 428 429 /* calculate array device size */ 430 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); 431 432 pr_debug("md/raid0:%s: md_size is %llu sectors.\n", 433 mdname(mddev), 434 (unsigned long long)mddev->array_sectors); 435 436 dump_zones(mddev); 437 438 return md_integrity_register(mddev); 439 } 440 441 /* 442 * Convert disk_index to the disk order in which it is read/written. 443 * For example, if we have 4 disks, they are numbered 0,1,2,3. If we 444 * write the disks starting at disk 3, then the read/write order would 445 * be disk 3, then 0, then 1, and then disk 2 and we want map_disk_shift() 446 * to map the disks as follows 0,1,2,3 => 1,2,3,0. So disk 0 would map 447 * to 1, 1 to 2, 2 to 3, and 3 to 0. That way we can compare disks in 448 * that 'output' space to understand the read/write disk ordering. 449 */ 450 static int map_disk_shift(int disk_index, int num_disks, int disk_shift) 451 { 452 return ((disk_index + num_disks - disk_shift) % num_disks); 453 } 454 455 static void raid0_handle_discard(struct mddev *mddev, struct bio *bio) 456 { 457 struct r0conf *conf = mddev->private; 458 struct strip_zone *zone; 459 sector_t start = bio->bi_iter.bi_sector; 460 sector_t end; 461 unsigned int stripe_size; 462 sector_t first_stripe_index, last_stripe_index; 463 sector_t start_disk_offset; 464 unsigned int start_disk_index; 465 sector_t end_disk_offset; 466 unsigned int end_disk_index; 467 unsigned int disk; 468 sector_t orig_start, orig_end; 469 470 orig_start = start; 471 zone = find_zone(conf, &start); 472 473 if (bio_end_sector(bio) > zone->zone_end) { 474 bio = bio_submit_split_bioset(bio, 475 zone->zone_end - bio->bi_iter.bi_sector, 476 &mddev->bio_set); 477 if (!bio) 478 return; 479 480 end = zone->zone_end; 481 } else { 482 end = bio_end_sector(bio); 483 } 484 485 orig_end = end; 486 if (zone != conf->strip_zone) 487 end = end - zone[-1].zone_end; 488 489 /* Now start and end is the offset in zone */ 490 stripe_size = zone->nb_dev * mddev->chunk_sectors; 491 492 first_stripe_index = start; 493 sector_div(first_stripe_index, stripe_size); 494 last_stripe_index = end; 495 sector_div(last_stripe_index, stripe_size); 496 497 /* In the first zone the original and alternate layouts are the same */ 498 if ((conf->layout == RAID0_ORIG_LAYOUT) && (zone != conf->strip_zone)) { 499 sector_div(orig_start, mddev->chunk_sectors); 500 start_disk_index = sector_div(orig_start, zone->nb_dev); 501 start_disk_index = map_disk_shift(start_disk_index, 502 zone->nb_dev, 503 zone->disk_shift); 504 sector_div(orig_end, mddev->chunk_sectors); 505 end_disk_index = sector_div(orig_end, zone->nb_dev); 506 end_disk_index = map_disk_shift(end_disk_index, 507 zone->nb_dev, zone->disk_shift); 508 } else { 509 start_disk_index = (int)(start - first_stripe_index * stripe_size) / 510 mddev->chunk_sectors; 511 end_disk_index = (int)(end - last_stripe_index * stripe_size) / 512 mddev->chunk_sectors; 513 } 514 start_disk_offset = ((int)(start - first_stripe_index * stripe_size) % 515 mddev->chunk_sectors) + 516 first_stripe_index * mddev->chunk_sectors; 517 end_disk_offset = ((int)(end - last_stripe_index * stripe_size) % 518 mddev->chunk_sectors) + 519 last_stripe_index * mddev->chunk_sectors; 520 521 for (disk = 0; disk < zone->nb_dev; disk++) { 522 sector_t dev_start, dev_end; 523 struct md_rdev *rdev; 524 int compare_disk; 525 526 compare_disk = map_disk_shift(disk, zone->nb_dev, 527 zone->disk_shift); 528 529 if (compare_disk < start_disk_index) 530 dev_start = (first_stripe_index + 1) * 531 mddev->chunk_sectors; 532 else if (compare_disk > start_disk_index) 533 dev_start = first_stripe_index * mddev->chunk_sectors; 534 else 535 dev_start = start_disk_offset; 536 537 if (compare_disk < end_disk_index) 538 dev_end = (last_stripe_index + 1) * mddev->chunk_sectors; 539 else if (compare_disk > end_disk_index) 540 dev_end = last_stripe_index * mddev->chunk_sectors; 541 else 542 dev_end = end_disk_offset; 543 544 if (dev_end <= dev_start) 545 continue; 546 547 rdev = conf->devlist[(zone - conf->strip_zone) * 548 conf->strip_zone[0].nb_dev + disk]; 549 md_submit_discard_bio(mddev, rdev, bio, 550 dev_start + zone->dev_start + rdev->data_offset, 551 dev_end - dev_start); 552 } 553 bio_endio(bio); 554 } 555 556 static void raid0_map_submit_bio(struct mddev *mddev, struct bio *bio) 557 { 558 struct r0conf *conf = mddev->private; 559 struct strip_zone *zone; 560 struct md_rdev *tmp_dev; 561 sector_t bio_sector = bio->bi_iter.bi_sector; 562 sector_t sector = bio_sector; 563 564 md_account_bio(mddev, &bio); 565 566 zone = find_zone(mddev->private, §or); 567 switch (conf->layout) { 568 case RAID0_ORIG_LAYOUT: 569 tmp_dev = map_sector(mddev, zone, bio_sector, §or); 570 break; 571 case RAID0_ALT_MULTIZONE_LAYOUT: 572 tmp_dev = map_sector(mddev, zone, sector, §or); 573 break; 574 default: 575 WARN(1, "md/raid0:%s: Invalid layout\n", mdname(mddev)); 576 bio_io_error(bio); 577 return; 578 } 579 580 if (unlikely(is_rdev_broken(tmp_dev))) { 581 bio_io_error(bio); 582 md_error(mddev, tmp_dev); 583 return; 584 } 585 586 bio_set_dev(bio, tmp_dev->bdev); 587 bio->bi_iter.bi_sector = sector + zone->dev_start + 588 tmp_dev->data_offset; 589 mddev_trace_remap(mddev, bio, bio_sector); 590 mddev_check_write_zeroes(mddev, bio); 591 submit_bio_noacct(bio); 592 } 593 594 static bool raid0_make_request(struct mddev *mddev, struct bio *bio) 595 { 596 sector_t sector; 597 unsigned chunk_sects; 598 unsigned sectors; 599 600 if (unlikely(bio->bi_opf & REQ_PREFLUSH) 601 && md_flush_request(mddev, bio)) 602 return true; 603 604 if (unlikely((bio_op(bio) == REQ_OP_DISCARD))) { 605 raid0_handle_discard(mddev, bio); 606 return true; 607 } 608 609 sector = bio->bi_iter.bi_sector; 610 chunk_sects = mddev->chunk_sectors; 611 612 sectors = chunk_sects - 613 (likely(is_power_of_2(chunk_sects)) 614 ? (sector & (chunk_sects-1)) 615 : sector_div(sector, chunk_sects)); 616 617 if (sectors < bio_sectors(bio)) { 618 bio = bio_submit_split_bioset(bio, sectors, 619 &mddev->bio_set); 620 if (!bio) 621 return true; 622 } 623 624 raid0_map_submit_bio(mddev, bio); 625 return true; 626 } 627 628 static void raid0_status(struct seq_file *seq, struct mddev *mddev) 629 { 630 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2); 631 return; 632 } 633 634 static void raid0_error(struct mddev *mddev, struct md_rdev *rdev) 635 { 636 if (!test_and_set_bit(MD_BROKEN, &mddev->flags)) { 637 char *md_name = mdname(mddev); 638 639 pr_crit("md/raid0%s: Disk failure on %pg detected, failing array.\n", 640 md_name, rdev->bdev); 641 } 642 } 643 644 static void *raid0_takeover_raid45(struct mddev *mddev) 645 { 646 struct md_rdev *rdev; 647 struct r0conf *priv_conf; 648 649 if (mddev->degraded != 1) { 650 pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n", 651 mdname(mddev), 652 mddev->degraded); 653 return ERR_PTR(-EINVAL); 654 } 655 656 rdev_for_each(rdev, mddev) { 657 /* check slot number for a disk */ 658 if (rdev->raid_disk == mddev->raid_disks-1) { 659 pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n", 660 mdname(mddev)); 661 return ERR_PTR(-EINVAL); 662 } 663 rdev->sectors = mddev->dev_sectors; 664 } 665 666 /* Set new parameters */ 667 mddev->new_level = 0; 668 mddev->new_layout = 0; 669 mddev->new_chunk_sectors = mddev->chunk_sectors; 670 mddev->raid_disks--; 671 mddev->delta_disks = -1; 672 /* make sure it will be not marked as dirty */ 673 mddev->resync_offset = MaxSector; 674 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); 675 676 create_strip_zones(mddev, &priv_conf); 677 678 return priv_conf; 679 } 680 681 static void *raid0_takeover_raid10(struct mddev *mddev) 682 { 683 struct r0conf *priv_conf; 684 685 /* Check layout: 686 * - far_copies must be 1 687 * - near_copies must be 2 688 * - disks number must be even 689 * - all mirrors must be already degraded 690 */ 691 if (mddev->layout != ((1 << 8) + 2)) { 692 pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n", 693 mdname(mddev), 694 mddev->layout); 695 return ERR_PTR(-EINVAL); 696 } 697 if (mddev->raid_disks & 1) { 698 pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n", 699 mdname(mddev)); 700 return ERR_PTR(-EINVAL); 701 } 702 if (mddev->degraded != (mddev->raid_disks>>1)) { 703 pr_warn("md/raid0:%s: All mirrors must be already degraded!\n", 704 mdname(mddev)); 705 return ERR_PTR(-EINVAL); 706 } 707 708 /* Set new parameters */ 709 mddev->new_level = 0; 710 mddev->new_layout = 0; 711 mddev->new_chunk_sectors = mddev->chunk_sectors; 712 mddev->delta_disks = - mddev->raid_disks / 2; 713 mddev->raid_disks += mddev->delta_disks; 714 mddev->degraded = 0; 715 /* make sure it will be not marked as dirty */ 716 mddev->resync_offset = MaxSector; 717 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); 718 719 create_strip_zones(mddev, &priv_conf); 720 return priv_conf; 721 } 722 723 static void *raid0_takeover_raid1(struct mddev *mddev) 724 { 725 struct r0conf *priv_conf; 726 int chunksect; 727 728 /* Check layout: 729 * - (N - 1) mirror drives must be already faulty 730 */ 731 if ((mddev->raid_disks - 1) != mddev->degraded) { 732 pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n", 733 mdname(mddev)); 734 return ERR_PTR(-EINVAL); 735 } 736 737 /* 738 * a raid1 doesn't have the notion of chunk size, so 739 * figure out the largest suitable size we can use. 740 */ 741 chunksect = 64 * 2; /* 64K by default */ 742 743 /* The array must be an exact multiple of chunksize */ 744 while (chunksect && (mddev->array_sectors & (chunksect - 1))) 745 chunksect >>= 1; 746 747 if ((chunksect << 9) < PAGE_SIZE) 748 /* array size does not allow a suitable chunk size */ 749 return ERR_PTR(-EINVAL); 750 751 /* Set new parameters */ 752 mddev->new_level = 0; 753 mddev->new_layout = 0; 754 mddev->new_chunk_sectors = chunksect; 755 mddev->chunk_sectors = chunksect; 756 mddev->delta_disks = 1 - mddev->raid_disks; 757 mddev->raid_disks = 1; 758 /* make sure it will be not marked as dirty */ 759 mddev->resync_offset = MaxSector; 760 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); 761 762 create_strip_zones(mddev, &priv_conf); 763 return priv_conf; 764 } 765 766 static void *raid0_takeover(struct mddev *mddev) 767 { 768 /* raid0 can take over: 769 * raid4 - if all data disks are active. 770 * raid5 - providing it is Raid4 layout and one disk is faulty 771 * raid10 - assuming we have all necessary active disks 772 * raid1 - with (N -1) mirror drives faulty 773 */ 774 775 if (mddev->bitmap) { 776 pr_warn("md/raid0: %s: cannot takeover array with bitmap\n", 777 mdname(mddev)); 778 return ERR_PTR(-EBUSY); 779 } 780 if (mddev->level == 4) 781 return raid0_takeover_raid45(mddev); 782 783 if (mddev->level == 5) { 784 if (mddev->layout == ALGORITHM_PARITY_N) 785 return raid0_takeover_raid45(mddev); 786 787 pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n", 788 mdname(mddev), ALGORITHM_PARITY_N); 789 } 790 791 if (mddev->level == 10) 792 return raid0_takeover_raid10(mddev); 793 794 if (mddev->level == 1) 795 return raid0_takeover_raid1(mddev); 796 797 pr_warn("Takeover from raid%i to raid0 not supported\n", 798 mddev->level); 799 800 return ERR_PTR(-EINVAL); 801 } 802 803 static void raid0_quiesce(struct mddev *mddev, int quiesce) 804 { 805 } 806 807 static struct md_personality raid0_personality= 808 { 809 .head = { 810 .type = MD_PERSONALITY, 811 .id = ID_RAID0, 812 .name = "raid0", 813 .owner = THIS_MODULE, 814 }, 815 816 .make_request = raid0_make_request, 817 .run = raid0_run, 818 .free = raid0_free, 819 .status = raid0_status, 820 .size = raid0_size, 821 .takeover = raid0_takeover, 822 .quiesce = raid0_quiesce, 823 .error_handler = raid0_error, 824 }; 825 826 static int __init raid0_init(void) 827 { 828 return register_md_submodule(&raid0_personality.head); 829 } 830 831 static void __exit raid0_exit(void) 832 { 833 unregister_md_submodule(&raid0_personality.head); 834 } 835 836 module_init(raid0_init); 837 module_exit(raid0_exit); 838 MODULE_LICENSE("GPL"); 839 MODULE_DESCRIPTION("RAID0 (striping) personality for MD"); 840 MODULE_ALIAS("md-personality-2"); /* RAID0 */ 841 MODULE_ALIAS("md-raid0"); 842 MODULE_ALIAS("md-level-0"); 843