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 "md.h" 25 #include "raid0.h" 26 #include "raid5.h" 27 28 static int raid0_congested(void *data, int bits) 29 { 30 struct mddev *mddev = data; 31 struct r0conf *conf = mddev->private; 32 struct md_rdev **devlist = conf->devlist; 33 int raid_disks = conf->strip_zone[0].nb_dev; 34 int i, ret = 0; 35 36 if (mddev_congested(mddev, bits)) 37 return 1; 38 39 for (i = 0; i < raid_disks && !ret ; i++) { 40 struct request_queue *q = bdev_get_queue(devlist[i]->bdev); 41 42 ret |= bdi_congested(&q->backing_dev_info, bits); 43 } 44 return ret; 45 } 46 47 /* 48 * inform the user of the raid configuration 49 */ 50 static void dump_zones(struct mddev *mddev) 51 { 52 int j, k; 53 sector_t zone_size = 0; 54 sector_t zone_start = 0; 55 char b[BDEVNAME_SIZE]; 56 struct r0conf *conf = mddev->private; 57 int raid_disks = conf->strip_zone[0].nb_dev; 58 printk(KERN_INFO "md: RAID0 configuration for %s - %d zone%s\n", 59 mdname(mddev), 60 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s"); 61 for (j = 0; j < conf->nr_strip_zones; j++) { 62 printk(KERN_INFO "md: zone%d=[", j); 63 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 64 printk(KERN_CONT "%s%s", k?"/":"", 65 bdevname(conf->devlist[j*raid_disks 66 + k]->bdev, b)); 67 printk(KERN_CONT "]\n"); 68 69 zone_size = conf->strip_zone[j].zone_end - zone_start; 70 printk(KERN_INFO " zone-offset=%10lluKB, " 71 "device-offset=%10lluKB, size=%10lluKB\n", 72 (unsigned long long)zone_start>>1, 73 (unsigned long long)conf->strip_zone[j].dev_start>>1, 74 (unsigned long long)zone_size>>1); 75 zone_start = conf->strip_zone[j].zone_end; 76 } 77 printk(KERN_INFO "\n"); 78 } 79 80 static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) 81 { 82 int i, c, err; 83 sector_t curr_zone_end, sectors; 84 struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev; 85 struct strip_zone *zone; 86 int cnt; 87 char b[BDEVNAME_SIZE]; 88 char b2[BDEVNAME_SIZE]; 89 struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL); 90 bool discard_supported = false; 91 92 if (!conf) 93 return -ENOMEM; 94 rdev_for_each(rdev1, mddev) { 95 pr_debug("md/raid0:%s: looking at %s\n", 96 mdname(mddev), 97 bdevname(rdev1->bdev, b)); 98 c = 0; 99 100 /* round size to chunk_size */ 101 sectors = rdev1->sectors; 102 sector_div(sectors, mddev->chunk_sectors); 103 rdev1->sectors = sectors * mddev->chunk_sectors; 104 105 rdev_for_each(rdev2, mddev) { 106 pr_debug("md/raid0:%s: comparing %s(%llu)" 107 " with %s(%llu)\n", 108 mdname(mddev), 109 bdevname(rdev1->bdev,b), 110 (unsigned long long)rdev1->sectors, 111 bdevname(rdev2->bdev,b2), 112 (unsigned long long)rdev2->sectors); 113 if (rdev2 == rdev1) { 114 pr_debug("md/raid0:%s: END\n", 115 mdname(mddev)); 116 break; 117 } 118 if (rdev2->sectors == rdev1->sectors) { 119 /* 120 * Not unique, don't count it as a new 121 * group 122 */ 123 pr_debug("md/raid0:%s: EQUAL\n", 124 mdname(mddev)); 125 c = 1; 126 break; 127 } 128 pr_debug("md/raid0:%s: NOT EQUAL\n", 129 mdname(mddev)); 130 } 131 if (!c) { 132 pr_debug("md/raid0:%s: ==> UNIQUE\n", 133 mdname(mddev)); 134 conf->nr_strip_zones++; 135 pr_debug("md/raid0:%s: %d zones\n", 136 mdname(mddev), conf->nr_strip_zones); 137 } 138 } 139 pr_debug("md/raid0:%s: FINAL %d zones\n", 140 mdname(mddev), conf->nr_strip_zones); 141 err = -ENOMEM; 142 conf->strip_zone = kzalloc(sizeof(struct strip_zone)* 143 conf->nr_strip_zones, GFP_KERNEL); 144 if (!conf->strip_zone) 145 goto abort; 146 conf->devlist = kzalloc(sizeof(struct md_rdev*)* 147 conf->nr_strip_zones*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 printk(KERN_ERR 179 "md/raid0:%s: remove inactive devices before converting to RAID0\n", 180 mdname(mddev)); 181 goto abort; 182 } 183 if (j >= mddev->raid_disks) { 184 printk(KERN_ERR "md/raid0:%s: bad disk number %d - " 185 "aborting!\n", mdname(mddev), j); 186 goto abort; 187 } 188 if (dev[j]) { 189 printk(KERN_ERR "md/raid0:%s: multiple devices for %d - " 190 "aborting!\n", mdname(mddev), j); 191 goto abort; 192 } 193 dev[j] = rdev1; 194 195 disk_stack_limits(mddev->gendisk, rdev1->bdev, 196 rdev1->data_offset << 9); 197 198 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) 199 conf->has_merge_bvec = 1; 200 201 if (!smallest || (rdev1->sectors < smallest->sectors)) 202 smallest = rdev1; 203 cnt++; 204 205 if (blk_queue_discard(bdev_get_queue(rdev1->bdev))) 206 discard_supported = true; 207 } 208 if (cnt != mddev->raid_disks) { 209 printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - " 210 "aborting!\n", mdname(mddev), cnt, mddev->raid_disks); 211 goto abort; 212 } 213 zone->nb_dev = cnt; 214 zone->zone_end = smallest->sectors * cnt; 215 216 curr_zone_end = zone->zone_end; 217 218 /* now do the other zones */ 219 for (i = 1; i < conf->nr_strip_zones; i++) 220 { 221 int j; 222 223 zone = conf->strip_zone + i; 224 dev = conf->devlist + i * mddev->raid_disks; 225 226 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i); 227 zone->dev_start = smallest->sectors; 228 smallest = NULL; 229 c = 0; 230 231 for (j=0; j<cnt; j++) { 232 rdev = conf->devlist[j]; 233 if (rdev->sectors <= zone->dev_start) { 234 pr_debug("md/raid0:%s: checking %s ... nope\n", 235 mdname(mddev), 236 bdevname(rdev->bdev, b)); 237 continue; 238 } 239 pr_debug("md/raid0:%s: checking %s ..." 240 " contained as device %d\n", 241 mdname(mddev), 242 bdevname(rdev->bdev, b), c); 243 dev[c] = rdev; 244 c++; 245 if (!smallest || rdev->sectors < smallest->sectors) { 246 smallest = rdev; 247 pr_debug("md/raid0:%s: (%llu) is smallest!.\n", 248 mdname(mddev), 249 (unsigned long long)rdev->sectors); 250 } 251 } 252 253 zone->nb_dev = c; 254 sectors = (smallest->sectors - zone->dev_start) * c; 255 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n", 256 mdname(mddev), 257 zone->nb_dev, (unsigned long long)sectors); 258 259 curr_zone_end += sectors; 260 zone->zone_end = curr_zone_end; 261 262 pr_debug("md/raid0:%s: current zone start: %llu\n", 263 mdname(mddev), 264 (unsigned long long)smallest->sectors); 265 } 266 mddev->queue->backing_dev_info.congested_fn = raid0_congested; 267 mddev->queue->backing_dev_info.congested_data = mddev; 268 269 /* 270 * now since we have the hard sector sizes, we can make sure 271 * chunk size is a multiple of that sector size 272 */ 273 if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) { 274 printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n", 275 mdname(mddev), 276 mddev->chunk_sectors << 9); 277 goto abort; 278 } 279 280 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9); 281 blk_queue_io_opt(mddev->queue, 282 (mddev->chunk_sectors << 9) * mddev->raid_disks); 283 284 if (!discard_supported) 285 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 286 else 287 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 288 289 pr_debug("md/raid0:%s: done.\n", mdname(mddev)); 290 *private_conf = conf; 291 292 return 0; 293 abort: 294 kfree(conf->strip_zone); 295 kfree(conf->devlist); 296 kfree(conf); 297 *private_conf = ERR_PTR(err); 298 return err; 299 } 300 301 /* Find the zone which holds a particular offset 302 * Update *sectorp to be an offset in that zone 303 */ 304 static struct strip_zone *find_zone(struct r0conf *conf, 305 sector_t *sectorp) 306 { 307 int i; 308 struct strip_zone *z = conf->strip_zone; 309 sector_t sector = *sectorp; 310 311 for (i = 0; i < conf->nr_strip_zones; i++) 312 if (sector < z[i].zone_end) { 313 if (i) 314 *sectorp = sector - z[i-1].zone_end; 315 return z + i; 316 } 317 BUG(); 318 } 319 320 /* 321 * remaps the bio to the target device. we separate two flows. 322 * power 2 flow and a general flow for the sake of perfromance 323 */ 324 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone, 325 sector_t sector, sector_t *sector_offset) 326 { 327 unsigned int sect_in_chunk; 328 sector_t chunk; 329 struct r0conf *conf = mddev->private; 330 int raid_disks = conf->strip_zone[0].nb_dev; 331 unsigned int chunk_sects = mddev->chunk_sectors; 332 333 if (is_power_of_2(chunk_sects)) { 334 int chunksect_bits = ffz(~chunk_sects); 335 /* find the sector offset inside the chunk */ 336 sect_in_chunk = sector & (chunk_sects - 1); 337 sector >>= chunksect_bits; 338 /* chunk in zone */ 339 chunk = *sector_offset; 340 /* quotient is the chunk in real device*/ 341 sector_div(chunk, zone->nb_dev << chunksect_bits); 342 } else{ 343 sect_in_chunk = sector_div(sector, chunk_sects); 344 chunk = *sector_offset; 345 sector_div(chunk, chunk_sects * zone->nb_dev); 346 } 347 /* 348 * position the bio over the real device 349 * real sector = chunk in device + starting of zone 350 * + the position in the chunk 351 */ 352 *sector_offset = (chunk * chunk_sects) + sect_in_chunk; 353 return conf->devlist[(zone - conf->strip_zone)*raid_disks 354 + sector_div(sector, zone->nb_dev)]; 355 } 356 357 /** 358 * raid0_mergeable_bvec -- tell bio layer if two requests can be merged 359 * @q: request queue 360 * @bvm: properties of new bio 361 * @biovec: the request that could be merged to it. 362 * 363 * Return amount of bytes we can accept at this offset 364 */ 365 static int raid0_mergeable_bvec(struct request_queue *q, 366 struct bvec_merge_data *bvm, 367 struct bio_vec *biovec) 368 { 369 struct mddev *mddev = q->queuedata; 370 struct r0conf *conf = mddev->private; 371 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); 372 sector_t sector_offset = sector; 373 int max; 374 unsigned int chunk_sectors = mddev->chunk_sectors; 375 unsigned int bio_sectors = bvm->bi_size >> 9; 376 struct strip_zone *zone; 377 struct md_rdev *rdev; 378 struct request_queue *subq; 379 380 if (is_power_of_2(chunk_sectors)) 381 max = (chunk_sectors - ((sector & (chunk_sectors-1)) 382 + bio_sectors)) << 9; 383 else 384 max = (chunk_sectors - (sector_div(sector, chunk_sectors) 385 + bio_sectors)) << 9; 386 if (max < 0) 387 max = 0; /* bio_add cannot handle a negative return */ 388 if (max <= biovec->bv_len && bio_sectors == 0) 389 return biovec->bv_len; 390 if (max < biovec->bv_len) 391 /* too small already, no need to check further */ 392 return max; 393 if (!conf->has_merge_bvec) 394 return max; 395 396 /* May need to check subordinate device */ 397 sector = sector_offset; 398 zone = find_zone(mddev->private, §or_offset); 399 rdev = map_sector(mddev, zone, sector, §or_offset); 400 subq = bdev_get_queue(rdev->bdev); 401 if (subq->merge_bvec_fn) { 402 bvm->bi_bdev = rdev->bdev; 403 bvm->bi_sector = sector_offset + zone->dev_start + 404 rdev->data_offset; 405 return min(max, subq->merge_bvec_fn(subq, bvm, biovec)); 406 } else 407 return max; 408 } 409 410 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks) 411 { 412 sector_t array_sectors = 0; 413 struct md_rdev *rdev; 414 415 WARN_ONCE(sectors || raid_disks, 416 "%s does not support generic reshape\n", __func__); 417 418 rdev_for_each(rdev, mddev) 419 array_sectors += (rdev->sectors & 420 ~(sector_t)(mddev->chunk_sectors-1)); 421 422 return array_sectors; 423 } 424 425 static int raid0_stop(struct mddev *mddev); 426 427 static int raid0_run(struct mddev *mddev) 428 { 429 struct r0conf *conf; 430 int ret; 431 432 if (mddev->chunk_sectors == 0) { 433 printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n", 434 mdname(mddev)); 435 return -EINVAL; 436 } 437 if (md_check_no_bitmap(mddev)) 438 return -EINVAL; 439 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); 440 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors); 441 blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors); 442 443 /* if private is not null, we are here after takeover */ 444 if (mddev->private == NULL) { 445 ret = create_strip_zones(mddev, &conf); 446 if (ret < 0) 447 return ret; 448 mddev->private = conf; 449 } 450 conf = mddev->private; 451 452 /* calculate array device size */ 453 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); 454 455 printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n", 456 mdname(mddev), 457 (unsigned long long)mddev->array_sectors); 458 /* calculate the max read-ahead size. 459 * For read-ahead of large files to be effective, we need to 460 * readahead at least twice a whole stripe. i.e. number of devices 461 * multiplied by chunk size times 2. 462 * If an individual device has an ra_pages greater than the 463 * chunk size, then we will not drive that device as hard as it 464 * wants. We consider this a configuration error: a larger 465 * chunksize should be used in that case. 466 */ 467 { 468 int stripe = mddev->raid_disks * 469 (mddev->chunk_sectors << 9) / PAGE_SIZE; 470 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) 471 mddev->queue->backing_dev_info.ra_pages = 2* stripe; 472 } 473 474 blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec); 475 dump_zones(mddev); 476 477 ret = md_integrity_register(mddev); 478 if (ret) 479 raid0_stop(mddev); 480 481 return ret; 482 } 483 484 static int raid0_stop(struct mddev *mddev) 485 { 486 struct r0conf *conf = mddev->private; 487 488 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 489 kfree(conf->strip_zone); 490 kfree(conf->devlist); 491 kfree(conf); 492 mddev->private = NULL; 493 return 0; 494 } 495 496 /* 497 * Is io distribute over 1 or more chunks ? 498 */ 499 static inline int is_io_in_chunk_boundary(struct mddev *mddev, 500 unsigned int chunk_sects, struct bio *bio) 501 { 502 if (likely(is_power_of_2(chunk_sects))) { 503 return chunk_sects >= 504 ((bio->bi_iter.bi_sector & (chunk_sects-1)) 505 + bio_sectors(bio)); 506 } else{ 507 sector_t sector = bio->bi_iter.bi_sector; 508 return chunk_sects >= (sector_div(sector, chunk_sects) 509 + bio_sectors(bio)); 510 } 511 } 512 513 static void raid0_make_request(struct mddev *mddev, struct bio *bio) 514 { 515 struct strip_zone *zone; 516 struct md_rdev *tmp_dev; 517 struct bio *split; 518 519 if (unlikely(bio->bi_rw & REQ_FLUSH)) { 520 md_flush_request(mddev, bio); 521 return; 522 } 523 524 do { 525 sector_t sector = bio->bi_iter.bi_sector; 526 unsigned chunk_sects = mddev->chunk_sectors; 527 528 unsigned sectors = chunk_sects - 529 (likely(is_power_of_2(chunk_sects)) 530 ? (sector & (chunk_sects-1)) 531 : sector_div(sector, chunk_sects)); 532 533 if (sectors < bio_sectors(bio)) { 534 split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set); 535 bio_chain(split, bio); 536 } else { 537 split = bio; 538 } 539 540 zone = find_zone(mddev->private, §or); 541 tmp_dev = map_sector(mddev, zone, sector, §or); 542 split->bi_bdev = tmp_dev->bdev; 543 split->bi_iter.bi_sector = sector + zone->dev_start + 544 tmp_dev->data_offset; 545 546 if (unlikely((split->bi_rw & REQ_DISCARD) && 547 !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) { 548 /* Just ignore it */ 549 bio_endio(split, 0); 550 } else 551 generic_make_request(split); 552 } while (split != bio); 553 } 554 555 static void raid0_status(struct seq_file *seq, struct mddev *mddev) 556 { 557 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2); 558 return; 559 } 560 561 static void *raid0_takeover_raid45(struct mddev *mddev) 562 { 563 struct md_rdev *rdev; 564 struct r0conf *priv_conf; 565 566 if (mddev->degraded != 1) { 567 printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n", 568 mdname(mddev), 569 mddev->degraded); 570 return ERR_PTR(-EINVAL); 571 } 572 573 rdev_for_each(rdev, mddev) { 574 /* check slot number for a disk */ 575 if (rdev->raid_disk == mddev->raid_disks-1) { 576 printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n", 577 mdname(mddev)); 578 return ERR_PTR(-EINVAL); 579 } 580 rdev->sectors = mddev->dev_sectors; 581 } 582 583 /* Set new parameters */ 584 mddev->new_level = 0; 585 mddev->new_layout = 0; 586 mddev->new_chunk_sectors = mddev->chunk_sectors; 587 mddev->raid_disks--; 588 mddev->delta_disks = -1; 589 /* make sure it will be not marked as dirty */ 590 mddev->recovery_cp = MaxSector; 591 592 create_strip_zones(mddev, &priv_conf); 593 return priv_conf; 594 } 595 596 static void *raid0_takeover_raid10(struct mddev *mddev) 597 { 598 struct r0conf *priv_conf; 599 600 /* Check layout: 601 * - far_copies must be 1 602 * - near_copies must be 2 603 * - disks number must be even 604 * - all mirrors must be already degraded 605 */ 606 if (mddev->layout != ((1 << 8) + 2)) { 607 printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takover layout: 0x%x\n", 608 mdname(mddev), 609 mddev->layout); 610 return ERR_PTR(-EINVAL); 611 } 612 if (mddev->raid_disks & 1) { 613 printk(KERN_ERR "md/raid0:%s: Raid0 cannot takover Raid10 with odd disk number.\n", 614 mdname(mddev)); 615 return ERR_PTR(-EINVAL); 616 } 617 if (mddev->degraded != (mddev->raid_disks>>1)) { 618 printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n", 619 mdname(mddev)); 620 return ERR_PTR(-EINVAL); 621 } 622 623 /* Set new parameters */ 624 mddev->new_level = 0; 625 mddev->new_layout = 0; 626 mddev->new_chunk_sectors = mddev->chunk_sectors; 627 mddev->delta_disks = - mddev->raid_disks / 2; 628 mddev->raid_disks += mddev->delta_disks; 629 mddev->degraded = 0; 630 /* make sure it will be not marked as dirty */ 631 mddev->recovery_cp = MaxSector; 632 633 create_strip_zones(mddev, &priv_conf); 634 return priv_conf; 635 } 636 637 static void *raid0_takeover_raid1(struct mddev *mddev) 638 { 639 struct r0conf *priv_conf; 640 int chunksect; 641 642 /* Check layout: 643 * - (N - 1) mirror drives must be already faulty 644 */ 645 if ((mddev->raid_disks - 1) != mddev->degraded) { 646 printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n", 647 mdname(mddev)); 648 return ERR_PTR(-EINVAL); 649 } 650 651 /* 652 * a raid1 doesn't have the notion of chunk size, so 653 * figure out the largest suitable size we can use. 654 */ 655 chunksect = 64 * 2; /* 64K by default */ 656 657 /* The array must be an exact multiple of chunksize */ 658 while (chunksect && (mddev->array_sectors & (chunksect - 1))) 659 chunksect >>= 1; 660 661 if ((chunksect << 9) < PAGE_SIZE) 662 /* array size does not allow a suitable chunk size */ 663 return ERR_PTR(-EINVAL); 664 665 /* Set new parameters */ 666 mddev->new_level = 0; 667 mddev->new_layout = 0; 668 mddev->new_chunk_sectors = chunksect; 669 mddev->chunk_sectors = chunksect; 670 mddev->delta_disks = 1 - mddev->raid_disks; 671 mddev->raid_disks = 1; 672 /* make sure it will be not marked as dirty */ 673 mddev->recovery_cp = MaxSector; 674 675 create_strip_zones(mddev, &priv_conf); 676 return priv_conf; 677 } 678 679 static void *raid0_takeover(struct mddev *mddev) 680 { 681 /* raid0 can take over: 682 * raid4 - if all data disks are active. 683 * raid5 - providing it is Raid4 layout and one disk is faulty 684 * raid10 - assuming we have all necessary active disks 685 * raid1 - with (N -1) mirror drives faulty 686 */ 687 688 if (mddev->bitmap) { 689 printk(KERN_ERR "md/raid0: %s: cannot takeover array with bitmap\n", 690 mdname(mddev)); 691 return ERR_PTR(-EBUSY); 692 } 693 if (mddev->level == 4) 694 return raid0_takeover_raid45(mddev); 695 696 if (mddev->level == 5) { 697 if (mddev->layout == ALGORITHM_PARITY_N) 698 return raid0_takeover_raid45(mddev); 699 700 printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n", 701 mdname(mddev), ALGORITHM_PARITY_N); 702 } 703 704 if (mddev->level == 10) 705 return raid0_takeover_raid10(mddev); 706 707 if (mddev->level == 1) 708 return raid0_takeover_raid1(mddev); 709 710 printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n", 711 mddev->level); 712 713 return ERR_PTR(-EINVAL); 714 } 715 716 static void raid0_quiesce(struct mddev *mddev, int state) 717 { 718 } 719 720 static struct md_personality raid0_personality= 721 { 722 .name = "raid0", 723 .level = 0, 724 .owner = THIS_MODULE, 725 .make_request = raid0_make_request, 726 .run = raid0_run, 727 .stop = raid0_stop, 728 .status = raid0_status, 729 .size = raid0_size, 730 .takeover = raid0_takeover, 731 .quiesce = raid0_quiesce, 732 }; 733 734 static int __init raid0_init (void) 735 { 736 return register_md_personality (&raid0_personality); 737 } 738 739 static void raid0_exit (void) 740 { 741 unregister_md_personality (&raid0_personality); 742 } 743 744 module_init(raid0_init); 745 module_exit(raid0_exit); 746 MODULE_LICENSE("GPL"); 747 MODULE_DESCRIPTION("RAID0 (striping) personality for MD"); 748 MODULE_ALIAS("md-personality-2"); /* RAID0 */ 749 MODULE_ALIAS("md-raid0"); 750 MODULE_ALIAS("md-level-0"); 751