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(struct mddev *mddev, int bits) 29 { 30 struct r0conf *conf = mddev->private; 31 struct md_rdev **devlist = conf->devlist; 32 int raid_disks = conf->strip_zone[0].nb_dev; 33 int i, ret = 0; 34 35 for (i = 0; i < raid_disks && !ret ; i++) { 36 struct request_queue *q = bdev_get_queue(devlist[i]->bdev); 37 38 ret |= bdi_congested(&q->backing_dev_info, bits); 39 } 40 return ret; 41 } 42 43 /* 44 * inform the user of the raid configuration 45 */ 46 static void dump_zones(struct mddev *mddev) 47 { 48 int j, k; 49 sector_t zone_size = 0; 50 sector_t zone_start = 0; 51 char b[BDEVNAME_SIZE]; 52 struct r0conf *conf = mddev->private; 53 int raid_disks = conf->strip_zone[0].nb_dev; 54 printk(KERN_INFO "md: RAID0 configuration for %s - %d zone%s\n", 55 mdname(mddev), 56 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s"); 57 for (j = 0; j < conf->nr_strip_zones; j++) { 58 printk(KERN_INFO "md: zone%d=[", j); 59 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 60 printk(KERN_CONT "%s%s", k?"/":"", 61 bdevname(conf->devlist[j*raid_disks 62 + k]->bdev, b)); 63 printk(KERN_CONT "]\n"); 64 65 zone_size = conf->strip_zone[j].zone_end - zone_start; 66 printk(KERN_INFO " zone-offset=%10lluKB, " 67 "device-offset=%10lluKB, size=%10lluKB\n", 68 (unsigned long long)zone_start>>1, 69 (unsigned long long)conf->strip_zone[j].dev_start>>1, 70 (unsigned long long)zone_size>>1); 71 zone_start = conf->strip_zone[j].zone_end; 72 } 73 printk(KERN_INFO "\n"); 74 } 75 76 static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) 77 { 78 int i, c, err; 79 sector_t curr_zone_end, sectors; 80 struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev; 81 struct strip_zone *zone; 82 int cnt; 83 char b[BDEVNAME_SIZE]; 84 char b2[BDEVNAME_SIZE]; 85 struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL); 86 bool discard_supported = false; 87 88 if (!conf) 89 return -ENOMEM; 90 rdev_for_each(rdev1, mddev) { 91 pr_debug("md/raid0:%s: looking at %s\n", 92 mdname(mddev), 93 bdevname(rdev1->bdev, b)); 94 c = 0; 95 96 /* round size to chunk_size */ 97 sectors = rdev1->sectors; 98 sector_div(sectors, mddev->chunk_sectors); 99 rdev1->sectors = sectors * mddev->chunk_sectors; 100 101 rdev_for_each(rdev2, mddev) { 102 pr_debug("md/raid0:%s: comparing %s(%llu)" 103 " with %s(%llu)\n", 104 mdname(mddev), 105 bdevname(rdev1->bdev,b), 106 (unsigned long long)rdev1->sectors, 107 bdevname(rdev2->bdev,b2), 108 (unsigned long long)rdev2->sectors); 109 if (rdev2 == rdev1) { 110 pr_debug("md/raid0:%s: END\n", 111 mdname(mddev)); 112 break; 113 } 114 if (rdev2->sectors == rdev1->sectors) { 115 /* 116 * Not unique, don't count it as a new 117 * group 118 */ 119 pr_debug("md/raid0:%s: EQUAL\n", 120 mdname(mddev)); 121 c = 1; 122 break; 123 } 124 pr_debug("md/raid0:%s: NOT EQUAL\n", 125 mdname(mddev)); 126 } 127 if (!c) { 128 pr_debug("md/raid0:%s: ==> UNIQUE\n", 129 mdname(mddev)); 130 conf->nr_strip_zones++; 131 pr_debug("md/raid0:%s: %d zones\n", 132 mdname(mddev), conf->nr_strip_zones); 133 } 134 } 135 pr_debug("md/raid0:%s: FINAL %d zones\n", 136 mdname(mddev), conf->nr_strip_zones); 137 err = -ENOMEM; 138 conf->strip_zone = kzalloc(sizeof(struct strip_zone)* 139 conf->nr_strip_zones, GFP_KERNEL); 140 if (!conf->strip_zone) 141 goto abort; 142 conf->devlist = kzalloc(sizeof(struct md_rdev*)* 143 conf->nr_strip_zones*mddev->raid_disks, 144 GFP_KERNEL); 145 if (!conf->devlist) 146 goto abort; 147 148 /* The first zone must contain all devices, so here we check that 149 * there is a proper alignment of slots to devices and find them all 150 */ 151 zone = &conf->strip_zone[0]; 152 cnt = 0; 153 smallest = NULL; 154 dev = conf->devlist; 155 err = -EINVAL; 156 rdev_for_each(rdev1, mddev) { 157 int j = rdev1->raid_disk; 158 159 if (mddev->level == 10) { 160 /* taking over a raid10-n2 array */ 161 j /= 2; 162 rdev1->new_raid_disk = j; 163 } 164 165 if (mddev->level == 1) { 166 /* taiking over a raid1 array- 167 * we have only one active disk 168 */ 169 j = 0; 170 rdev1->new_raid_disk = j; 171 } 172 173 if (j < 0) { 174 printk(KERN_ERR 175 "md/raid0:%s: remove inactive devices before converting to RAID0\n", 176 mdname(mddev)); 177 goto abort; 178 } 179 if (j >= mddev->raid_disks) { 180 printk(KERN_ERR "md/raid0:%s: bad disk number %d - " 181 "aborting!\n", mdname(mddev), j); 182 goto abort; 183 } 184 if (dev[j]) { 185 printk(KERN_ERR "md/raid0:%s: multiple devices for %d - " 186 "aborting!\n", mdname(mddev), j); 187 goto abort; 188 } 189 dev[j] = rdev1; 190 191 if (mddev->queue) 192 disk_stack_limits(mddev->gendisk, rdev1->bdev, 193 rdev1->data_offset << 9); 194 195 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) 196 conf->has_merge_bvec = 1; 197 198 if (!smallest || (rdev1->sectors < smallest->sectors)) 199 smallest = rdev1; 200 cnt++; 201 202 if (blk_queue_discard(bdev_get_queue(rdev1->bdev))) 203 discard_supported = true; 204 } 205 if (cnt != mddev->raid_disks) { 206 printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - " 207 "aborting!\n", mdname(mddev), cnt, mddev->raid_disks); 208 goto abort; 209 } 210 zone->nb_dev = cnt; 211 zone->zone_end = smallest->sectors * cnt; 212 213 curr_zone_end = zone->zone_end; 214 215 /* now do the other zones */ 216 for (i = 1; i < conf->nr_strip_zones; i++) 217 { 218 int j; 219 220 zone = conf->strip_zone + i; 221 dev = conf->devlist + i * mddev->raid_disks; 222 223 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i); 224 zone->dev_start = smallest->sectors; 225 smallest = NULL; 226 c = 0; 227 228 for (j=0; j<cnt; j++) { 229 rdev = conf->devlist[j]; 230 if (rdev->sectors <= zone->dev_start) { 231 pr_debug("md/raid0:%s: checking %s ... nope\n", 232 mdname(mddev), 233 bdevname(rdev->bdev, b)); 234 continue; 235 } 236 pr_debug("md/raid0:%s: checking %s ..." 237 " contained as device %d\n", 238 mdname(mddev), 239 bdevname(rdev->bdev, b), c); 240 dev[c] = rdev; 241 c++; 242 if (!smallest || rdev->sectors < smallest->sectors) { 243 smallest = rdev; 244 pr_debug("md/raid0:%s: (%llu) is smallest!.\n", 245 mdname(mddev), 246 (unsigned long long)rdev->sectors); 247 } 248 } 249 250 zone->nb_dev = c; 251 sectors = (smallest->sectors - zone->dev_start) * c; 252 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n", 253 mdname(mddev), 254 zone->nb_dev, (unsigned long long)sectors); 255 256 curr_zone_end += sectors; 257 zone->zone_end = curr_zone_end; 258 259 pr_debug("md/raid0:%s: current zone start: %llu\n", 260 mdname(mddev), 261 (unsigned long long)smallest->sectors); 262 } 263 264 /* 265 * now since we have the hard sector sizes, we can make sure 266 * chunk size is a multiple of that sector size 267 */ 268 if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) { 269 printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n", 270 mdname(mddev), 271 mddev->chunk_sectors << 9); 272 goto abort; 273 } 274 275 if (mddev->queue) { 276 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9); 277 blk_queue_io_opt(mddev->queue, 278 (mddev->chunk_sectors << 9) * mddev->raid_disks); 279 280 if (!discard_supported) 281 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 282 else 283 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 284 } 285 286 pr_debug("md/raid0:%s: done.\n", mdname(mddev)); 287 *private_conf = conf; 288 289 return 0; 290 abort: 291 kfree(conf->strip_zone); 292 kfree(conf->devlist); 293 kfree(conf); 294 *private_conf = ERR_PTR(err); 295 return err; 296 } 297 298 /* Find the zone which holds a particular offset 299 * Update *sectorp to be an offset in that zone 300 */ 301 static struct strip_zone *find_zone(struct r0conf *conf, 302 sector_t *sectorp) 303 { 304 int i; 305 struct strip_zone *z = conf->strip_zone; 306 sector_t sector = *sectorp; 307 308 for (i = 0; i < conf->nr_strip_zones; i++) 309 if (sector < z[i].zone_end) { 310 if (i) 311 *sectorp = sector - z[i-1].zone_end; 312 return z + i; 313 } 314 BUG(); 315 } 316 317 /* 318 * remaps the bio to the target device. we separate two flows. 319 * power 2 flow and a general flow for the sake of performance 320 */ 321 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone, 322 sector_t sector, sector_t *sector_offset) 323 { 324 unsigned int sect_in_chunk; 325 sector_t chunk; 326 struct r0conf *conf = mddev->private; 327 int raid_disks = conf->strip_zone[0].nb_dev; 328 unsigned int chunk_sects = mddev->chunk_sectors; 329 330 if (is_power_of_2(chunk_sects)) { 331 int chunksect_bits = ffz(~chunk_sects); 332 /* find the sector offset inside the chunk */ 333 sect_in_chunk = sector & (chunk_sects - 1); 334 sector >>= chunksect_bits; 335 /* chunk in zone */ 336 chunk = *sector_offset; 337 /* quotient is the chunk in real device*/ 338 sector_div(chunk, zone->nb_dev << chunksect_bits); 339 } else{ 340 sect_in_chunk = sector_div(sector, chunk_sects); 341 chunk = *sector_offset; 342 sector_div(chunk, chunk_sects * zone->nb_dev); 343 } 344 /* 345 * position the bio over the real device 346 * real sector = chunk in device + starting of zone 347 * + the position in the chunk 348 */ 349 *sector_offset = (chunk * chunk_sects) + sect_in_chunk; 350 return conf->devlist[(zone - conf->strip_zone)*raid_disks 351 + sector_div(sector, zone->nb_dev)]; 352 } 353 354 /** 355 * raid0_mergeable_bvec -- tell bio layer if two requests can be merged 356 * @mddev: the md device 357 * @bvm: properties of new bio 358 * @biovec: the request that could be merged to it. 359 * 360 * Return amount of bytes we can accept at this offset 361 */ 362 static int raid0_mergeable_bvec(struct mddev *mddev, 363 struct bvec_merge_data *bvm, 364 struct bio_vec *biovec) 365 { 366 struct r0conf *conf = mddev->private; 367 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); 368 sector_t sector_offset = sector; 369 int max; 370 unsigned int chunk_sectors = mddev->chunk_sectors; 371 unsigned int bio_sectors = bvm->bi_size >> 9; 372 struct strip_zone *zone; 373 struct md_rdev *rdev; 374 struct request_queue *subq; 375 376 if (is_power_of_2(chunk_sectors)) 377 max = (chunk_sectors - ((sector & (chunk_sectors-1)) 378 + bio_sectors)) << 9; 379 else 380 max = (chunk_sectors - (sector_div(sector, chunk_sectors) 381 + bio_sectors)) << 9; 382 if (max < 0) 383 max = 0; /* bio_add cannot handle a negative return */ 384 if (max <= biovec->bv_len && bio_sectors == 0) 385 return biovec->bv_len; 386 if (max < biovec->bv_len) 387 /* too small already, no need to check further */ 388 return max; 389 if (!conf->has_merge_bvec) 390 return max; 391 392 /* May need to check subordinate device */ 393 sector = sector_offset; 394 zone = find_zone(mddev->private, §or_offset); 395 rdev = map_sector(mddev, zone, sector, §or_offset); 396 subq = bdev_get_queue(rdev->bdev); 397 if (subq->merge_bvec_fn) { 398 bvm->bi_bdev = rdev->bdev; 399 bvm->bi_sector = sector_offset + zone->dev_start + 400 rdev->data_offset; 401 return min(max, subq->merge_bvec_fn(subq, bvm, biovec)); 402 } else 403 return max; 404 } 405 406 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks) 407 { 408 sector_t array_sectors = 0; 409 struct md_rdev *rdev; 410 411 WARN_ONCE(sectors || raid_disks, 412 "%s does not support generic reshape\n", __func__); 413 414 rdev_for_each(rdev, mddev) 415 array_sectors += (rdev->sectors & 416 ~(sector_t)(mddev->chunk_sectors-1)); 417 418 return array_sectors; 419 } 420 421 static void raid0_free(struct mddev *mddev, void *priv); 422 423 static int raid0_run(struct mddev *mddev) 424 { 425 struct r0conf *conf; 426 int ret; 427 428 if (mddev->chunk_sectors == 0) { 429 printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n", 430 mdname(mddev)); 431 return -EINVAL; 432 } 433 if (md_check_no_bitmap(mddev)) 434 return -EINVAL; 435 436 if (mddev->queue) { 437 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); 438 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors); 439 blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors); 440 } 441 442 /* if private is not null, we are here after takeover */ 443 if (mddev->private == NULL) { 444 ret = create_strip_zones(mddev, &conf); 445 if (ret < 0) 446 return ret; 447 mddev->private = conf; 448 } 449 conf = mddev->private; 450 451 /* calculate array device size */ 452 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); 453 454 printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n", 455 mdname(mddev), 456 (unsigned long long)mddev->array_sectors); 457 458 if (mddev->queue) { 459 /* calculate the max read-ahead size. 460 * For read-ahead of large files to be effective, we need to 461 * readahead at least twice a whole stripe. i.e. number of devices 462 * multiplied by chunk size times 2. 463 * If an individual device has an ra_pages greater than the 464 * chunk size, then we will not drive that device as hard as it 465 * wants. We consider this a configuration error: a larger 466 * chunksize should be used in that case. 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 dump_zones(mddev); 475 476 ret = md_integrity_register(mddev); 477 478 return ret; 479 } 480 481 static void raid0_free(struct mddev *mddev, void *priv) 482 { 483 struct r0conf *conf = priv; 484 485 kfree(conf->strip_zone); 486 kfree(conf->devlist); 487 kfree(conf); 488 } 489 490 /* 491 * Is io distribute over 1 or more chunks ? 492 */ 493 static inline int is_io_in_chunk_boundary(struct mddev *mddev, 494 unsigned int chunk_sects, struct bio *bio) 495 { 496 if (likely(is_power_of_2(chunk_sects))) { 497 return chunk_sects >= 498 ((bio->bi_iter.bi_sector & (chunk_sects-1)) 499 + bio_sectors(bio)); 500 } else{ 501 sector_t sector = bio->bi_iter.bi_sector; 502 return chunk_sects >= (sector_div(sector, chunk_sects) 503 + bio_sectors(bio)); 504 } 505 } 506 507 static void raid0_make_request(struct mddev *mddev, struct bio *bio) 508 { 509 struct strip_zone *zone; 510 struct md_rdev *tmp_dev; 511 struct bio *split; 512 513 if (unlikely(bio->bi_rw & REQ_FLUSH)) { 514 md_flush_request(mddev, bio); 515 return; 516 } 517 518 do { 519 sector_t sector = bio->bi_iter.bi_sector; 520 unsigned chunk_sects = mddev->chunk_sectors; 521 522 unsigned sectors = chunk_sects - 523 (likely(is_power_of_2(chunk_sects)) 524 ? (sector & (chunk_sects-1)) 525 : sector_div(sector, chunk_sects)); 526 527 if (sectors < bio_sectors(bio)) { 528 split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set); 529 bio_chain(split, bio); 530 } else { 531 split = bio; 532 } 533 534 sector = bio->bi_iter.bi_sector; 535 zone = find_zone(mddev->private, §or); 536 tmp_dev = map_sector(mddev, zone, sector, §or); 537 split->bi_bdev = tmp_dev->bdev; 538 split->bi_iter.bi_sector = sector + zone->dev_start + 539 tmp_dev->data_offset; 540 541 if (unlikely((split->bi_rw & REQ_DISCARD) && 542 !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) { 543 /* Just ignore it */ 544 bio_endio(split, 0); 545 } else 546 generic_make_request(split); 547 } while (split != bio); 548 } 549 550 static void raid0_status(struct seq_file *seq, struct mddev *mddev) 551 { 552 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2); 553 return; 554 } 555 556 static void *raid0_takeover_raid45(struct mddev *mddev) 557 { 558 struct md_rdev *rdev; 559 struct r0conf *priv_conf; 560 561 if (mddev->degraded != 1) { 562 printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n", 563 mdname(mddev), 564 mddev->degraded); 565 return ERR_PTR(-EINVAL); 566 } 567 568 rdev_for_each(rdev, mddev) { 569 /* check slot number for a disk */ 570 if (rdev->raid_disk == mddev->raid_disks-1) { 571 printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n", 572 mdname(mddev)); 573 return ERR_PTR(-EINVAL); 574 } 575 rdev->sectors = mddev->dev_sectors; 576 } 577 578 /* Set new parameters */ 579 mddev->new_level = 0; 580 mddev->new_layout = 0; 581 mddev->new_chunk_sectors = mddev->chunk_sectors; 582 mddev->raid_disks--; 583 mddev->delta_disks = -1; 584 /* make sure it will be not marked as dirty */ 585 mddev->recovery_cp = MaxSector; 586 587 create_strip_zones(mddev, &priv_conf); 588 return priv_conf; 589 } 590 591 static void *raid0_takeover_raid10(struct mddev *mddev) 592 { 593 struct r0conf *priv_conf; 594 595 /* Check layout: 596 * - far_copies must be 1 597 * - near_copies must be 2 598 * - disks number must be even 599 * - all mirrors must be already degraded 600 */ 601 if (mddev->layout != ((1 << 8) + 2)) { 602 printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takover layout: 0x%x\n", 603 mdname(mddev), 604 mddev->layout); 605 return ERR_PTR(-EINVAL); 606 } 607 if (mddev->raid_disks & 1) { 608 printk(KERN_ERR "md/raid0:%s: Raid0 cannot takover Raid10 with odd disk number.\n", 609 mdname(mddev)); 610 return ERR_PTR(-EINVAL); 611 } 612 if (mddev->degraded != (mddev->raid_disks>>1)) { 613 printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n", 614 mdname(mddev)); 615 return ERR_PTR(-EINVAL); 616 } 617 618 /* Set new parameters */ 619 mddev->new_level = 0; 620 mddev->new_layout = 0; 621 mddev->new_chunk_sectors = mddev->chunk_sectors; 622 mddev->delta_disks = - mddev->raid_disks / 2; 623 mddev->raid_disks += mddev->delta_disks; 624 mddev->degraded = 0; 625 /* make sure it will be not marked as dirty */ 626 mddev->recovery_cp = MaxSector; 627 628 create_strip_zones(mddev, &priv_conf); 629 return priv_conf; 630 } 631 632 static void *raid0_takeover_raid1(struct mddev *mddev) 633 { 634 struct r0conf *priv_conf; 635 int chunksect; 636 637 /* Check layout: 638 * - (N - 1) mirror drives must be already faulty 639 */ 640 if ((mddev->raid_disks - 1) != mddev->degraded) { 641 printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n", 642 mdname(mddev)); 643 return ERR_PTR(-EINVAL); 644 } 645 646 /* 647 * a raid1 doesn't have the notion of chunk size, so 648 * figure out the largest suitable size we can use. 649 */ 650 chunksect = 64 * 2; /* 64K by default */ 651 652 /* The array must be an exact multiple of chunksize */ 653 while (chunksect && (mddev->array_sectors & (chunksect - 1))) 654 chunksect >>= 1; 655 656 if ((chunksect << 9) < PAGE_SIZE) 657 /* array size does not allow a suitable chunk size */ 658 return ERR_PTR(-EINVAL); 659 660 /* Set new parameters */ 661 mddev->new_level = 0; 662 mddev->new_layout = 0; 663 mddev->new_chunk_sectors = chunksect; 664 mddev->chunk_sectors = chunksect; 665 mddev->delta_disks = 1 - mddev->raid_disks; 666 mddev->raid_disks = 1; 667 /* make sure it will be not marked as dirty */ 668 mddev->recovery_cp = MaxSector; 669 670 create_strip_zones(mddev, &priv_conf); 671 return priv_conf; 672 } 673 674 static void *raid0_takeover(struct mddev *mddev) 675 { 676 /* raid0 can take over: 677 * raid4 - if all data disks are active. 678 * raid5 - providing it is Raid4 layout and one disk is faulty 679 * raid10 - assuming we have all necessary active disks 680 * raid1 - with (N -1) mirror drives faulty 681 */ 682 683 if (mddev->bitmap) { 684 printk(KERN_ERR "md/raid0: %s: cannot takeover array with bitmap\n", 685 mdname(mddev)); 686 return ERR_PTR(-EBUSY); 687 } 688 if (mddev->level == 4) 689 return raid0_takeover_raid45(mddev); 690 691 if (mddev->level == 5) { 692 if (mddev->layout == ALGORITHM_PARITY_N) 693 return raid0_takeover_raid45(mddev); 694 695 printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n", 696 mdname(mddev), ALGORITHM_PARITY_N); 697 } 698 699 if (mddev->level == 10) 700 return raid0_takeover_raid10(mddev); 701 702 if (mddev->level == 1) 703 return raid0_takeover_raid1(mddev); 704 705 printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n", 706 mddev->level); 707 708 return ERR_PTR(-EINVAL); 709 } 710 711 static void raid0_quiesce(struct mddev *mddev, int state) 712 { 713 } 714 715 static struct md_personality raid0_personality= 716 { 717 .name = "raid0", 718 .level = 0, 719 .owner = THIS_MODULE, 720 .make_request = raid0_make_request, 721 .run = raid0_run, 722 .free = raid0_free, 723 .status = raid0_status, 724 .size = raid0_size, 725 .takeover = raid0_takeover, 726 .quiesce = raid0_quiesce, 727 .congested = raid0_congested, 728 .mergeable_bvec = raid0_mergeable_bvec, 729 }; 730 731 static int __init raid0_init (void) 732 { 733 return register_md_personality (&raid0_personality); 734 } 735 736 static void raid0_exit (void) 737 { 738 unregister_md_personality (&raid0_personality); 739 } 740 741 module_init(raid0_init); 742 module_exit(raid0_exit); 743 MODULE_LICENSE("GPL"); 744 MODULE_DESCRIPTION("RAID0 (striping) personality for MD"); 745 MODULE_ALIAS("md-personality-2"); /* RAID0 */ 746 MODULE_ALIAS("md-raid0"); 747 MODULE_ALIAS("md-level-0"); 748