1 /* 2 raid0.c : Multiple Devices driver for Linux 3 Copyright (C) 1994-96 Marc ZYNGIER 4 <zyngier@ufr-info-p7.ibp.fr> or 5 <maz@gloups.fdn.fr> 6 Copyright (C) 1999, 2000 Ingo Molnar, Red Hat 7 8 RAID-0 management functions. 9 10 This program is free software; you can redistribute it and/or modify 11 it under the terms of the GNU General Public License as published by 12 the Free Software Foundation; either version 2, or (at your option) 13 any later version. 14 15 You should have received a copy of the GNU General Public License 16 (for example /usr/src/linux/COPYING); if not, write to the Free 17 Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 18 */ 19 20 #include <linux/blkdev.h> 21 #include <linux/seq_file.h> 22 #include <linux/module.h> 23 #include <linux/slab.h> 24 #include <trace/events/block.h> 25 #include "md.h" 26 #include "raid0.h" 27 #include "raid5.h" 28 29 #define UNSUPPORTED_MDDEV_FLAGS \ 30 ((1L << MD_HAS_JOURNAL) | \ 31 (1L << MD_JOURNAL_CLEAN) | \ 32 (1L << MD_FAILFAST_SUPPORTED) |\ 33 (1L << MD_HAS_PPL) | \ 34 (1L << MD_HAS_MULTIPLE_PPLS)) 35 36 static int raid0_congested(struct mddev *mddev, int bits) 37 { 38 struct r0conf *conf = mddev->private; 39 struct md_rdev **devlist = conf->devlist; 40 int raid_disks = conf->strip_zone[0].nb_dev; 41 int i, ret = 0; 42 43 for (i = 0; i < raid_disks && !ret ; i++) { 44 struct request_queue *q = bdev_get_queue(devlist[i]->bdev); 45 46 ret |= bdi_congested(q->backing_dev_info, bits); 47 } 48 return ret; 49 } 50 51 /* 52 * inform the user of the raid configuration 53 */ 54 static void dump_zones(struct mddev *mddev) 55 { 56 int j, k; 57 sector_t zone_size = 0; 58 sector_t zone_start = 0; 59 char b[BDEVNAME_SIZE]; 60 struct r0conf *conf = mddev->private; 61 int raid_disks = conf->strip_zone[0].nb_dev; 62 pr_debug("md: RAID0 configuration for %s - %d zone%s\n", 63 mdname(mddev), 64 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s"); 65 for (j = 0; j < conf->nr_strip_zones; j++) { 66 char line[200]; 67 int len = 0; 68 69 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 70 len += snprintf(line+len, 200-len, "%s%s", k?"/":"", 71 bdevname(conf->devlist[j*raid_disks 72 + k]->bdev, b)); 73 pr_debug("md: zone%d=[%s]\n", j, line); 74 75 zone_size = conf->strip_zone[j].zone_end - zone_start; 76 pr_debug(" zone-offset=%10lluKB, device-offset=%10lluKB, size=%10lluKB\n", 77 (unsigned long long)zone_start>>1, 78 (unsigned long long)conf->strip_zone[j].dev_start>>1, 79 (unsigned long long)zone_size>>1); 80 zone_start = conf->strip_zone[j].zone_end; 81 } 82 } 83 84 static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) 85 { 86 int i, c, err; 87 sector_t curr_zone_end, sectors; 88 struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev; 89 struct strip_zone *zone; 90 int cnt; 91 char b[BDEVNAME_SIZE]; 92 char b2[BDEVNAME_SIZE]; 93 struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL); 94 unsigned short blksize = 512; 95 96 *private_conf = ERR_PTR(-ENOMEM); 97 if (!conf) 98 return -ENOMEM; 99 rdev_for_each(rdev1, mddev) { 100 pr_debug("md/raid0:%s: looking at %s\n", 101 mdname(mddev), 102 bdevname(rdev1->bdev, b)); 103 c = 0; 104 105 /* round size to chunk_size */ 106 sectors = rdev1->sectors; 107 sector_div(sectors, mddev->chunk_sectors); 108 rdev1->sectors = sectors * mddev->chunk_sectors; 109 110 blksize = max(blksize, queue_logical_block_size( 111 rdev1->bdev->bd_disk->queue)); 112 113 rdev_for_each(rdev2, mddev) { 114 pr_debug("md/raid0:%s: comparing %s(%llu)" 115 " with %s(%llu)\n", 116 mdname(mddev), 117 bdevname(rdev1->bdev,b), 118 (unsigned long long)rdev1->sectors, 119 bdevname(rdev2->bdev,b2), 120 (unsigned long long)rdev2->sectors); 121 if (rdev2 == rdev1) { 122 pr_debug("md/raid0:%s: END\n", 123 mdname(mddev)); 124 break; 125 } 126 if (rdev2->sectors == rdev1->sectors) { 127 /* 128 * Not unique, don't count it as a new 129 * group 130 */ 131 pr_debug("md/raid0:%s: EQUAL\n", 132 mdname(mddev)); 133 c = 1; 134 break; 135 } 136 pr_debug("md/raid0:%s: NOT EQUAL\n", 137 mdname(mddev)); 138 } 139 if (!c) { 140 pr_debug("md/raid0:%s: ==> UNIQUE\n", 141 mdname(mddev)); 142 conf->nr_strip_zones++; 143 pr_debug("md/raid0:%s: %d zones\n", 144 mdname(mddev), conf->nr_strip_zones); 145 } 146 } 147 pr_debug("md/raid0:%s: FINAL %d zones\n", 148 mdname(mddev), conf->nr_strip_zones); 149 /* 150 * now since we have the hard sector sizes, we can make sure 151 * chunk size is a multiple of that sector size 152 */ 153 if ((mddev->chunk_sectors << 9) % blksize) { 154 pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n", 155 mdname(mddev), 156 mddev->chunk_sectors << 9, blksize); 157 err = -EINVAL; 158 goto abort; 159 } 160 161 err = -ENOMEM; 162 conf->strip_zone = kzalloc(sizeof(struct strip_zone)* 163 conf->nr_strip_zones, GFP_KERNEL); 164 if (!conf->strip_zone) 165 goto abort; 166 conf->devlist = kzalloc(sizeof(struct md_rdev*)* 167 conf->nr_strip_zones*mddev->raid_disks, 168 GFP_KERNEL); 169 if (!conf->devlist) 170 goto abort; 171 172 /* The first zone must contain all devices, so here we check that 173 * there is a proper alignment of slots to devices and find them all 174 */ 175 zone = &conf->strip_zone[0]; 176 cnt = 0; 177 smallest = NULL; 178 dev = conf->devlist; 179 err = -EINVAL; 180 rdev_for_each(rdev1, mddev) { 181 int j = rdev1->raid_disk; 182 183 if (mddev->level == 10) { 184 /* taking over a raid10-n2 array */ 185 j /= 2; 186 rdev1->new_raid_disk = j; 187 } 188 189 if (mddev->level == 1) { 190 /* taiking over a raid1 array- 191 * we have only one active disk 192 */ 193 j = 0; 194 rdev1->new_raid_disk = j; 195 } 196 197 if (j < 0) { 198 pr_warn("md/raid0:%s: remove inactive devices before converting to RAID0\n", 199 mdname(mddev)); 200 goto abort; 201 } 202 if (j >= mddev->raid_disks) { 203 pr_warn("md/raid0:%s: bad disk number %d - aborting!\n", 204 mdname(mddev), j); 205 goto abort; 206 } 207 if (dev[j]) { 208 pr_warn("md/raid0:%s: multiple devices for %d - aborting!\n", 209 mdname(mddev), j); 210 goto abort; 211 } 212 dev[j] = rdev1; 213 214 if (!smallest || (rdev1->sectors < smallest->sectors)) 215 smallest = rdev1; 216 cnt++; 217 } 218 if (cnt != mddev->raid_disks) { 219 pr_warn("md/raid0:%s: too few disks (%d of %d) - aborting!\n", 220 mdname(mddev), cnt, mddev->raid_disks); 221 goto abort; 222 } 223 zone->nb_dev = cnt; 224 zone->zone_end = smallest->sectors * cnt; 225 226 curr_zone_end = zone->zone_end; 227 228 /* now do the other zones */ 229 for (i = 1; i < conf->nr_strip_zones; i++) 230 { 231 int j; 232 233 zone = conf->strip_zone + i; 234 dev = conf->devlist + i * mddev->raid_disks; 235 236 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i); 237 zone->dev_start = smallest->sectors; 238 smallest = NULL; 239 c = 0; 240 241 for (j=0; j<cnt; j++) { 242 rdev = conf->devlist[j]; 243 if (rdev->sectors <= zone->dev_start) { 244 pr_debug("md/raid0:%s: checking %s ... nope\n", 245 mdname(mddev), 246 bdevname(rdev->bdev, b)); 247 continue; 248 } 249 pr_debug("md/raid0:%s: checking %s ..." 250 " contained as device %d\n", 251 mdname(mddev), 252 bdevname(rdev->bdev, b), c); 253 dev[c] = rdev; 254 c++; 255 if (!smallest || rdev->sectors < smallest->sectors) { 256 smallest = rdev; 257 pr_debug("md/raid0:%s: (%llu) is smallest!.\n", 258 mdname(mddev), 259 (unsigned long long)rdev->sectors); 260 } 261 } 262 263 zone->nb_dev = c; 264 sectors = (smallest->sectors - zone->dev_start) * c; 265 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n", 266 mdname(mddev), 267 zone->nb_dev, (unsigned long long)sectors); 268 269 curr_zone_end += sectors; 270 zone->zone_end = curr_zone_end; 271 272 pr_debug("md/raid0:%s: current zone start: %llu\n", 273 mdname(mddev), 274 (unsigned long long)smallest->sectors); 275 } 276 277 pr_debug("md/raid0:%s: done.\n", mdname(mddev)); 278 *private_conf = conf; 279 280 return 0; 281 abort: 282 kfree(conf->strip_zone); 283 kfree(conf->devlist); 284 kfree(conf); 285 *private_conf = ERR_PTR(err); 286 return err; 287 } 288 289 /* Find the zone which holds a particular offset 290 * Update *sectorp to be an offset in that zone 291 */ 292 static struct strip_zone *find_zone(struct r0conf *conf, 293 sector_t *sectorp) 294 { 295 int i; 296 struct strip_zone *z = conf->strip_zone; 297 sector_t sector = *sectorp; 298 299 for (i = 0; i < conf->nr_strip_zones; i++) 300 if (sector < z[i].zone_end) { 301 if (i) 302 *sectorp = sector - z[i-1].zone_end; 303 return z + i; 304 } 305 BUG(); 306 } 307 308 /* 309 * remaps the bio to the target device. we separate two flows. 310 * power 2 flow and a general flow for the sake of performance 311 */ 312 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone, 313 sector_t sector, sector_t *sector_offset) 314 { 315 unsigned int sect_in_chunk; 316 sector_t chunk; 317 struct r0conf *conf = mddev->private; 318 int raid_disks = conf->strip_zone[0].nb_dev; 319 unsigned int chunk_sects = mddev->chunk_sectors; 320 321 if (is_power_of_2(chunk_sects)) { 322 int chunksect_bits = ffz(~chunk_sects); 323 /* find the sector offset inside the chunk */ 324 sect_in_chunk = sector & (chunk_sects - 1); 325 sector >>= chunksect_bits; 326 /* chunk in zone */ 327 chunk = *sector_offset; 328 /* quotient is the chunk in real device*/ 329 sector_div(chunk, zone->nb_dev << chunksect_bits); 330 } else{ 331 sect_in_chunk = sector_div(sector, chunk_sects); 332 chunk = *sector_offset; 333 sector_div(chunk, chunk_sects * zone->nb_dev); 334 } 335 /* 336 * position the bio over the real device 337 * real sector = chunk in device + starting of zone 338 * + the position in the chunk 339 */ 340 *sector_offset = (chunk * chunk_sects) + sect_in_chunk; 341 return conf->devlist[(zone - conf->strip_zone)*raid_disks 342 + sector_div(sector, zone->nb_dev)]; 343 } 344 345 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks) 346 { 347 sector_t array_sectors = 0; 348 struct md_rdev *rdev; 349 350 WARN_ONCE(sectors || raid_disks, 351 "%s does not support generic reshape\n", __func__); 352 353 rdev_for_each(rdev, mddev) 354 array_sectors += (rdev->sectors & 355 ~(sector_t)(mddev->chunk_sectors-1)); 356 357 return array_sectors; 358 } 359 360 static void raid0_free(struct mddev *mddev, void *priv); 361 362 static int raid0_run(struct mddev *mddev) 363 { 364 struct r0conf *conf; 365 int ret; 366 367 if (mddev->chunk_sectors == 0) { 368 pr_warn("md/raid0:%s: chunk size must be set.\n", mdname(mddev)); 369 return -EINVAL; 370 } 371 if (md_check_no_bitmap(mddev)) 372 return -EINVAL; 373 374 /* if private is not null, we are here after takeover */ 375 if (mddev->private == NULL) { 376 ret = create_strip_zones(mddev, &conf); 377 if (ret < 0) 378 return ret; 379 mddev->private = conf; 380 } 381 conf = mddev->private; 382 if (mddev->queue) { 383 struct md_rdev *rdev; 384 bool discard_supported = false; 385 386 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); 387 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors); 388 blk_queue_max_write_zeroes_sectors(mddev->queue, mddev->chunk_sectors); 389 blk_queue_max_discard_sectors(mddev->queue, UINT_MAX); 390 391 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9); 392 blk_queue_io_opt(mddev->queue, 393 (mddev->chunk_sectors << 9) * mddev->raid_disks); 394 395 rdev_for_each(rdev, mddev) { 396 disk_stack_limits(mddev->gendisk, rdev->bdev, 397 rdev->data_offset << 9); 398 if (blk_queue_discard(bdev_get_queue(rdev->bdev))) 399 discard_supported = true; 400 } 401 if (!discard_supported) 402 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 403 else 404 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 405 } 406 407 /* calculate array device size */ 408 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); 409 410 pr_debug("md/raid0:%s: md_size is %llu sectors.\n", 411 mdname(mddev), 412 (unsigned long long)mddev->array_sectors); 413 414 if (mddev->queue) { 415 /* calculate the max read-ahead size. 416 * For read-ahead of large files to be effective, we need to 417 * readahead at least twice a whole stripe. i.e. number of devices 418 * multiplied by chunk size times 2. 419 * If an individual device has an ra_pages greater than the 420 * chunk size, then we will not drive that device as hard as it 421 * wants. We consider this a configuration error: a larger 422 * chunksize should be used in that case. 423 */ 424 int stripe = mddev->raid_disks * 425 (mddev->chunk_sectors << 9) / PAGE_SIZE; 426 if (mddev->queue->backing_dev_info->ra_pages < 2* stripe) 427 mddev->queue->backing_dev_info->ra_pages = 2* stripe; 428 } 429 430 dump_zones(mddev); 431 432 ret = md_integrity_register(mddev); 433 434 return ret; 435 } 436 437 static void raid0_free(struct mddev *mddev, void *priv) 438 { 439 struct r0conf *conf = priv; 440 441 kfree(conf->strip_zone); 442 kfree(conf->devlist); 443 kfree(conf); 444 } 445 446 /* 447 * Is io distribute over 1 or more chunks ? 448 */ 449 static inline int is_io_in_chunk_boundary(struct mddev *mddev, 450 unsigned int chunk_sects, struct bio *bio) 451 { 452 if (likely(is_power_of_2(chunk_sects))) { 453 return chunk_sects >= 454 ((bio->bi_iter.bi_sector & (chunk_sects-1)) 455 + bio_sectors(bio)); 456 } else{ 457 sector_t sector = bio->bi_iter.bi_sector; 458 return chunk_sects >= (sector_div(sector, chunk_sects) 459 + bio_sectors(bio)); 460 } 461 } 462 463 static void raid0_handle_discard(struct mddev *mddev, struct bio *bio) 464 { 465 struct r0conf *conf = mddev->private; 466 struct strip_zone *zone; 467 sector_t start = bio->bi_iter.bi_sector; 468 sector_t end; 469 unsigned int stripe_size; 470 sector_t first_stripe_index, last_stripe_index; 471 sector_t start_disk_offset; 472 unsigned int start_disk_index; 473 sector_t end_disk_offset; 474 unsigned int end_disk_index; 475 unsigned int disk; 476 477 zone = find_zone(conf, &start); 478 479 if (bio_end_sector(bio) > zone->zone_end) { 480 struct bio *split = bio_split(bio, 481 zone->zone_end - bio->bi_iter.bi_sector, GFP_NOIO, 482 mddev->bio_set); 483 bio_chain(split, bio); 484 generic_make_request(bio); 485 bio = split; 486 end = zone->zone_end; 487 } else 488 end = bio_end_sector(bio); 489 490 if (zone != conf->strip_zone) 491 end = end - zone[-1].zone_end; 492 493 /* Now start and end is the offset in zone */ 494 stripe_size = zone->nb_dev * mddev->chunk_sectors; 495 496 first_stripe_index = start; 497 sector_div(first_stripe_index, stripe_size); 498 last_stripe_index = end; 499 sector_div(last_stripe_index, stripe_size); 500 501 start_disk_index = (int)(start - first_stripe_index * stripe_size) / 502 mddev->chunk_sectors; 503 start_disk_offset = ((int)(start - first_stripe_index * stripe_size) % 504 mddev->chunk_sectors) + 505 first_stripe_index * mddev->chunk_sectors; 506 end_disk_index = (int)(end - last_stripe_index * stripe_size) / 507 mddev->chunk_sectors; 508 end_disk_offset = ((int)(end - last_stripe_index * stripe_size) % 509 mddev->chunk_sectors) + 510 last_stripe_index * mddev->chunk_sectors; 511 512 for (disk = 0; disk < zone->nb_dev; disk++) { 513 sector_t dev_start, dev_end; 514 struct bio *discard_bio = NULL; 515 struct md_rdev *rdev; 516 517 if (disk < start_disk_index) 518 dev_start = (first_stripe_index + 1) * 519 mddev->chunk_sectors; 520 else if (disk > start_disk_index) 521 dev_start = first_stripe_index * mddev->chunk_sectors; 522 else 523 dev_start = start_disk_offset; 524 525 if (disk < end_disk_index) 526 dev_end = (last_stripe_index + 1) * mddev->chunk_sectors; 527 else if (disk > end_disk_index) 528 dev_end = last_stripe_index * mddev->chunk_sectors; 529 else 530 dev_end = end_disk_offset; 531 532 if (dev_end <= dev_start) 533 continue; 534 535 rdev = conf->devlist[(zone - conf->strip_zone) * 536 conf->strip_zone[0].nb_dev + disk]; 537 if (__blkdev_issue_discard(rdev->bdev, 538 dev_start + zone->dev_start + rdev->data_offset, 539 dev_end - dev_start, GFP_NOIO, 0, &discard_bio) || 540 !discard_bio) 541 continue; 542 bio_chain(discard_bio, bio); 543 bio_clone_blkcg_association(discard_bio, bio); 544 if (mddev->gendisk) 545 trace_block_bio_remap(bdev_get_queue(rdev->bdev), 546 discard_bio, disk_devt(mddev->gendisk), 547 bio->bi_iter.bi_sector); 548 generic_make_request(discard_bio); 549 } 550 bio_endio(bio); 551 } 552 553 static bool raid0_make_request(struct mddev *mddev, struct bio *bio) 554 { 555 struct strip_zone *zone; 556 struct md_rdev *tmp_dev; 557 sector_t bio_sector; 558 sector_t sector; 559 unsigned chunk_sects; 560 unsigned sectors; 561 562 if (unlikely(bio->bi_opf & REQ_PREFLUSH)) { 563 md_flush_request(mddev, bio); 564 return true; 565 } 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, mddev->bio_set); 586 bio_chain(split, bio); 587 generic_make_request(bio); 588 bio = split; 589 } 590 591 zone = find_zone(mddev->private, §or); 592 tmp_dev = map_sector(mddev, zone, sector, §or); 593 bio_set_dev(bio, tmp_dev->bdev); 594 bio->bi_iter.bi_sector = sector + zone->dev_start + 595 tmp_dev->data_offset; 596 597 if (mddev->gendisk) 598 trace_block_bio_remap(bio->bi_disk->queue, bio, 599 disk_devt(mddev->gendisk), bio_sector); 600 mddev_check_writesame(mddev, bio); 601 mddev_check_write_zeroes(mddev, bio); 602 generic_make_request(bio); 603 return true; 604 } 605 606 static void raid0_status(struct seq_file *seq, struct mddev *mddev) 607 { 608 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2); 609 return; 610 } 611 612 static void *raid0_takeover_raid45(struct mddev *mddev) 613 { 614 struct md_rdev *rdev; 615 struct r0conf *priv_conf; 616 617 if (mddev->degraded != 1) { 618 pr_warn("md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n", 619 mdname(mddev), 620 mddev->degraded); 621 return ERR_PTR(-EINVAL); 622 } 623 624 rdev_for_each(rdev, mddev) { 625 /* check slot number for a disk */ 626 if (rdev->raid_disk == mddev->raid_disks-1) { 627 pr_warn("md/raid0:%s: raid5 must have missing parity disk!\n", 628 mdname(mddev)); 629 return ERR_PTR(-EINVAL); 630 } 631 rdev->sectors = mddev->dev_sectors; 632 } 633 634 /* Set new parameters */ 635 mddev->new_level = 0; 636 mddev->new_layout = 0; 637 mddev->new_chunk_sectors = mddev->chunk_sectors; 638 mddev->raid_disks--; 639 mddev->delta_disks = -1; 640 /* make sure it will be not marked as dirty */ 641 mddev->recovery_cp = MaxSector; 642 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); 643 644 create_strip_zones(mddev, &priv_conf); 645 646 return priv_conf; 647 } 648 649 static void *raid0_takeover_raid10(struct mddev *mddev) 650 { 651 struct r0conf *priv_conf; 652 653 /* Check layout: 654 * - far_copies must be 1 655 * - near_copies must be 2 656 * - disks number must be even 657 * - all mirrors must be already degraded 658 */ 659 if (mddev->layout != ((1 << 8) + 2)) { 660 pr_warn("md/raid0:%s:: Raid0 cannot takeover layout: 0x%x\n", 661 mdname(mddev), 662 mddev->layout); 663 return ERR_PTR(-EINVAL); 664 } 665 if (mddev->raid_disks & 1) { 666 pr_warn("md/raid0:%s: Raid0 cannot takeover Raid10 with odd disk number.\n", 667 mdname(mddev)); 668 return ERR_PTR(-EINVAL); 669 } 670 if (mddev->degraded != (mddev->raid_disks>>1)) { 671 pr_warn("md/raid0:%s: All mirrors must be already degraded!\n", 672 mdname(mddev)); 673 return ERR_PTR(-EINVAL); 674 } 675 676 /* Set new parameters */ 677 mddev->new_level = 0; 678 mddev->new_layout = 0; 679 mddev->new_chunk_sectors = mddev->chunk_sectors; 680 mddev->delta_disks = - mddev->raid_disks / 2; 681 mddev->raid_disks += mddev->delta_disks; 682 mddev->degraded = 0; 683 /* make sure it will be not marked as dirty */ 684 mddev->recovery_cp = MaxSector; 685 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); 686 687 create_strip_zones(mddev, &priv_conf); 688 return priv_conf; 689 } 690 691 static void *raid0_takeover_raid1(struct mddev *mddev) 692 { 693 struct r0conf *priv_conf; 694 int chunksect; 695 696 /* Check layout: 697 * - (N - 1) mirror drives must be already faulty 698 */ 699 if ((mddev->raid_disks - 1) != mddev->degraded) { 700 pr_err("md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n", 701 mdname(mddev)); 702 return ERR_PTR(-EINVAL); 703 } 704 705 /* 706 * a raid1 doesn't have the notion of chunk size, so 707 * figure out the largest suitable size we can use. 708 */ 709 chunksect = 64 * 2; /* 64K by default */ 710 711 /* The array must be an exact multiple of chunksize */ 712 while (chunksect && (mddev->array_sectors & (chunksect - 1))) 713 chunksect >>= 1; 714 715 if ((chunksect << 9) < PAGE_SIZE) 716 /* array size does not allow a suitable chunk size */ 717 return ERR_PTR(-EINVAL); 718 719 /* Set new parameters */ 720 mddev->new_level = 0; 721 mddev->new_layout = 0; 722 mddev->new_chunk_sectors = chunksect; 723 mddev->chunk_sectors = chunksect; 724 mddev->delta_disks = 1 - mddev->raid_disks; 725 mddev->raid_disks = 1; 726 /* make sure it will be not marked as dirty */ 727 mddev->recovery_cp = MaxSector; 728 mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS); 729 730 create_strip_zones(mddev, &priv_conf); 731 return priv_conf; 732 } 733 734 static void *raid0_takeover(struct mddev *mddev) 735 { 736 /* raid0 can take over: 737 * raid4 - if all data disks are active. 738 * raid5 - providing it is Raid4 layout and one disk is faulty 739 * raid10 - assuming we have all necessary active disks 740 * raid1 - with (N -1) mirror drives faulty 741 */ 742 743 if (mddev->bitmap) { 744 pr_warn("md/raid0: %s: cannot takeover array with bitmap\n", 745 mdname(mddev)); 746 return ERR_PTR(-EBUSY); 747 } 748 if (mddev->level == 4) 749 return raid0_takeover_raid45(mddev); 750 751 if (mddev->level == 5) { 752 if (mddev->layout == ALGORITHM_PARITY_N) 753 return raid0_takeover_raid45(mddev); 754 755 pr_warn("md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n", 756 mdname(mddev), ALGORITHM_PARITY_N); 757 } 758 759 if (mddev->level == 10) 760 return raid0_takeover_raid10(mddev); 761 762 if (mddev->level == 1) 763 return raid0_takeover_raid1(mddev); 764 765 pr_warn("Takeover from raid%i to raid0 not supported\n", 766 mddev->level); 767 768 return ERR_PTR(-EINVAL); 769 } 770 771 static void raid0_quiesce(struct mddev *mddev, int state) 772 { 773 } 774 775 static struct md_personality raid0_personality= 776 { 777 .name = "raid0", 778 .level = 0, 779 .owner = THIS_MODULE, 780 .make_request = raid0_make_request, 781 .run = raid0_run, 782 .free = raid0_free, 783 .status = raid0_status, 784 .size = raid0_size, 785 .takeover = raid0_takeover, 786 .quiesce = raid0_quiesce, 787 .congested = raid0_congested, 788 }; 789 790 static int __init raid0_init (void) 791 { 792 return register_md_personality (&raid0_personality); 793 } 794 795 static void raid0_exit (void) 796 { 797 unregister_md_personality (&raid0_personality); 798 } 799 800 module_init(raid0_init); 801 module_exit(raid0_exit); 802 MODULE_LICENSE("GPL"); 803 MODULE_DESCRIPTION("RAID0 (striping) personality for MD"); 804 MODULE_ALIAS("md-personality-2"); /* RAID0 */ 805 MODULE_ALIAS("md-raid0"); 806 MODULE_ALIAS("md-level-0"); 807