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 28static 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*/ 46static 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 76static 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 unsigned short blksize = 512; 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 blksize = max(blksize, queue_logical_block_size( 102 rdev1->bdev->bd_disk->queue)); 103 104 rdev_for_each(rdev2, mddev) { 105 pr_debug("md/raid0:%s: comparing %s(%llu)" 106 " with %s(%llu)\n", 107 mdname(mddev), 108 bdevname(rdev1->bdev,b), 109 (unsigned long long)rdev1->sectors, 110 bdevname(rdev2->bdev,b2), 111 (unsigned long long)rdev2->sectors); 112 if (rdev2 == rdev1) { 113 pr_debug("md/raid0:%s: END\n", 114 mdname(mddev)); 115 break; 116 } 117 if (rdev2->sectors == rdev1->sectors) { 118 /* 119 * Not unique, don't count it as a new 120 * group 121 */ 122 pr_debug("md/raid0:%s: EQUAL\n", 123 mdname(mddev)); 124 c = 1; 125 break; 126 } 127 pr_debug("md/raid0:%s: NOT EQUAL\n", 128 mdname(mddev)); 129 } 130 if (!c) { 131 pr_debug("md/raid0:%s: ==> UNIQUE\n", 132 mdname(mddev)); 133 conf->nr_strip_zones++; 134 pr_debug("md/raid0:%s: %d zones\n", 135 mdname(mddev), conf->nr_strip_zones); 136 } 137 } 138 pr_debug("md/raid0:%s: FINAL %d zones\n", 139 mdname(mddev), conf->nr_strip_zones); 140 /* 141 * now since we have the hard sector sizes, we can make sure 142 * chunk size is a multiple of that sector size 143 */ 144 if ((mddev->chunk_sectors << 9) % blksize) { 145 printk(KERN_ERR "md/raid0:%s: chunk_size of %d not multiple of block size %d\n", 146 mdname(mddev), 147 mddev->chunk_sectors << 9, blksize); 148 err = -EINVAL; 149 goto abort; 150 } 151 152 err = -ENOMEM; 153 conf->strip_zone = kzalloc(sizeof(struct strip_zone)* 154 conf->nr_strip_zones, GFP_KERNEL); 155 if (!conf->strip_zone) 156 goto abort; 157 conf->devlist = kzalloc(sizeof(struct md_rdev*)* 158 conf->nr_strip_zones*mddev->raid_disks, 159 GFP_KERNEL); 160 if (!conf->devlist) 161 goto abort; 162 163 /* The first zone must contain all devices, so here we check that 164 * there is a proper alignment of slots to devices and find them all 165 */ 166 zone = &conf->strip_zone[0]; 167 cnt = 0; 168 smallest = NULL; 169 dev = conf->devlist; 170 err = -EINVAL; 171 rdev_for_each(rdev1, mddev) { 172 int j = rdev1->raid_disk; 173 174 if (mddev->level == 10) { 175 /* taking over a raid10-n2 array */ 176 j /= 2; 177 rdev1->new_raid_disk = j; 178 } 179 180 if (mddev->level == 1) { 181 /* taiking over a raid1 array- 182 * we have only one active disk 183 */ 184 j = 0; 185 rdev1->new_raid_disk = j; 186 } 187 188 if (j < 0) { 189 printk(KERN_ERR 190 "md/raid0:%s: remove inactive devices before converting to RAID0\n", 191 mdname(mddev)); 192 goto abort; 193 } 194 if (j >= mddev->raid_disks) { 195 printk(KERN_ERR "md/raid0:%s: bad disk number %d - " 196 "aborting!\n", mdname(mddev), j); 197 goto abort; 198 } 199 if (dev[j]) { 200 printk(KERN_ERR "md/raid0:%s: multiple devices for %d - " 201 "aborting!\n", mdname(mddev), j); 202 goto abort; 203 } 204 dev[j] = rdev1; 205 206 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) 207 conf->has_merge_bvec = 1; 208 209 if (!smallest || (rdev1->sectors < smallest->sectors)) 210 smallest = rdev1; 211 cnt++; 212 } 213 if (cnt != mddev->raid_disks) { 214 printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - " 215 "aborting!\n", mdname(mddev), cnt, mddev->raid_disks); 216 goto abort; 217 } 218 zone->nb_dev = cnt; 219 zone->zone_end = smallest->sectors * cnt; 220 221 curr_zone_end = zone->zone_end; 222 223 /* now do the other zones */ 224 for (i = 1; i < conf->nr_strip_zones; i++) 225 { 226 int j; 227 228 zone = conf->strip_zone + i; 229 dev = conf->devlist + i * mddev->raid_disks; 230 231 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i); 232 zone->dev_start = smallest->sectors; 233 smallest = NULL; 234 c = 0; 235 236 for (j=0; j<cnt; j++) { 237 rdev = conf->devlist[j]; 238 if (rdev->sectors <= zone->dev_start) { 239 pr_debug("md/raid0:%s: checking %s ... nope\n", 240 mdname(mddev), 241 bdevname(rdev->bdev, b)); 242 continue; 243 } 244 pr_debug("md/raid0:%s: checking %s ..." 245 " contained as device %d\n", 246 mdname(mddev), 247 bdevname(rdev->bdev, b), c); 248 dev[c] = rdev; 249 c++; 250 if (!smallest || rdev->sectors < smallest->sectors) { 251 smallest = rdev; 252 pr_debug("md/raid0:%s: (%llu) is smallest!.\n", 253 mdname(mddev), 254 (unsigned long long)rdev->sectors); 255 } 256 } 257 258 zone->nb_dev = c; 259 sectors = (smallest->sectors - zone->dev_start) * c; 260 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n", 261 mdname(mddev), 262 zone->nb_dev, (unsigned long long)sectors); 263 264 curr_zone_end += sectors; 265 zone->zone_end = curr_zone_end; 266 267 pr_debug("md/raid0:%s: current zone start: %llu\n", 268 mdname(mddev), 269 (unsigned long long)smallest->sectors); 270 } 271 272 pr_debug("md/raid0:%s: done.\n", mdname(mddev)); 273 *private_conf = conf; 274 275 return 0; 276abort: 277 kfree(conf->strip_zone); 278 kfree(conf->devlist); 279 kfree(conf); 280 *private_conf = ERR_PTR(err); 281 return err; 282} 283 284/* Find the zone which holds a particular offset 285 * Update *sectorp to be an offset in that zone 286 */ 287static struct strip_zone *find_zone(struct r0conf *conf, 288 sector_t *sectorp) 289{ 290 int i; 291 struct strip_zone *z = conf->strip_zone; 292 sector_t sector = *sectorp; 293 294 for (i = 0; i < conf->nr_strip_zones; i++) 295 if (sector < z[i].zone_end) { 296 if (i) 297 *sectorp = sector - z[i-1].zone_end; 298 return z + i; 299 } 300 BUG(); 301} 302 303/* 304 * remaps the bio to the target device. we separate two flows. 305 * power 2 flow and a general flow for the sake of performance 306*/ 307static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone, 308 sector_t sector, sector_t *sector_offset) 309{ 310 unsigned int sect_in_chunk; 311 sector_t chunk; 312 struct r0conf *conf = mddev->private; 313 int raid_disks = conf->strip_zone[0].nb_dev; 314 unsigned int chunk_sects = mddev->chunk_sectors; 315 316 if (is_power_of_2(chunk_sects)) { 317 int chunksect_bits = ffz(~chunk_sects); 318 /* find the sector offset inside the chunk */ 319 sect_in_chunk = sector & (chunk_sects - 1); 320 sector >>= chunksect_bits; 321 /* chunk in zone */ 322 chunk = *sector_offset; 323 /* quotient is the chunk in real device*/ 324 sector_div(chunk, zone->nb_dev << chunksect_bits); 325 } else{ 326 sect_in_chunk = sector_div(sector, chunk_sects); 327 chunk = *sector_offset; 328 sector_div(chunk, chunk_sects * zone->nb_dev); 329 } 330 /* 331 * position the bio over the real device 332 * real sector = chunk in device + starting of zone 333 * + the position in the chunk 334 */ 335 *sector_offset = (chunk * chunk_sects) + sect_in_chunk; 336 return conf->devlist[(zone - conf->strip_zone)*raid_disks 337 + sector_div(sector, zone->nb_dev)]; 338} 339 340/** 341 * raid0_mergeable_bvec -- tell bio layer if two requests can be merged 342 * @mddev: the md device 343 * @bvm: properties of new bio 344 * @biovec: the request that could be merged to it. 345 * 346 * Return amount of bytes we can accept at this offset 347 */ 348static int raid0_mergeable_bvec(struct mddev *mddev, 349 struct bvec_merge_data *bvm, 350 struct bio_vec *biovec) 351{ 352 struct r0conf *conf = mddev->private; 353 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); 354 sector_t sector_offset = sector; 355 int max; 356 unsigned int chunk_sectors = mddev->chunk_sectors; 357 unsigned int bio_sectors = bvm->bi_size >> 9; 358 struct strip_zone *zone; 359 struct md_rdev *rdev; 360 struct request_queue *subq; 361 362 if (is_power_of_2(chunk_sectors)) 363 max = (chunk_sectors - ((sector & (chunk_sectors-1)) 364 + bio_sectors)) << 9; 365 else 366 max = (chunk_sectors - (sector_div(sector, chunk_sectors) 367 + bio_sectors)) << 9; 368 if (max < 0) 369 max = 0; /* bio_add cannot handle a negative return */ 370 if (max <= biovec->bv_len && bio_sectors == 0) 371 return biovec->bv_len; 372 if (max < biovec->bv_len) 373 /* too small already, no need to check further */ 374 return max; 375 if (!conf->has_merge_bvec) 376 return max; 377 378 /* May need to check subordinate device */ 379 sector = sector_offset; 380 zone = find_zone(mddev->private, §or_offset); 381 rdev = map_sector(mddev, zone, sector, §or_offset); 382 subq = bdev_get_queue(rdev->bdev); 383 if (subq->merge_bvec_fn) { 384 bvm->bi_bdev = rdev->bdev; 385 bvm->bi_sector = sector_offset + zone->dev_start + 386 rdev->data_offset; 387 return min(max, subq->merge_bvec_fn(subq, bvm, biovec)); 388 } else 389 return max; 390} 391 392static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks) 393{ 394 sector_t array_sectors = 0; 395 struct md_rdev *rdev; 396 397 WARN_ONCE(sectors || raid_disks, 398 "%s does not support generic reshape\n", __func__); 399 400 rdev_for_each(rdev, mddev) 401 array_sectors += (rdev->sectors & 402 ~(sector_t)(mddev->chunk_sectors-1)); 403 404 return array_sectors; 405} 406 407static void raid0_free(struct mddev *mddev, void *priv); 408 409static int raid0_run(struct mddev *mddev) 410{ 411 struct r0conf *conf; 412 int ret; 413 414 if (mddev->chunk_sectors == 0) { 415 printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n", 416 mdname(mddev)); 417 return -EINVAL; 418 } 419 if (md_check_no_bitmap(mddev)) 420 return -EINVAL; 421 422 /* if private is not null, we are here after takeover */ 423 if (mddev->private == NULL) { 424 ret = create_strip_zones(mddev, &conf); 425 if (ret < 0) 426 return ret; 427 mddev->private = conf; 428 } 429 conf = mddev->private; 430 if (mddev->queue) { 431 struct md_rdev *rdev; 432 bool discard_supported = false; 433 434 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); 435 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors); 436 blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors); 437 438 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9); 439 blk_queue_io_opt(mddev->queue, 440 (mddev->chunk_sectors << 9) * mddev->raid_disks); 441 442 rdev_for_each(rdev, mddev) { 443 disk_stack_limits(mddev->gendisk, rdev->bdev, 444 rdev->data_offset << 9); 445 if (blk_queue_discard(bdev_get_queue(rdev->bdev))) 446 discard_supported = true; 447 } 448 if (!discard_supported) 449 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 450 else 451 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 452 } 453 454 /* calculate array device size */ 455 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); 456 457 printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n", 458 mdname(mddev), 459 (unsigned long long)mddev->array_sectors); 460 461 if (mddev->queue) { 462 /* calculate the max read-ahead size. 463 * For read-ahead of large files to be effective, we need to 464 * readahead at least twice a whole stripe. i.e. number of devices 465 * multiplied by chunk size times 2. 466 * If an individual device has an ra_pages greater than the 467 * chunk size, then we will not drive that device as hard as it 468 * wants. We consider this a configuration error: a larger 469 * chunksize should be used in that case. 470 */ 471 int stripe = mddev->raid_disks * 472 (mddev->chunk_sectors << 9) / PAGE_SIZE; 473 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) 474 mddev->queue->backing_dev_info.ra_pages = 2* stripe; 475 } 476 477 dump_zones(mddev); 478 479 ret = md_integrity_register(mddev); 480 481 return ret; 482} 483 484static void raid0_free(struct mddev *mddev, void *priv) 485{ 486 struct r0conf *conf = priv; 487 488 kfree(conf->strip_zone); 489 kfree(conf->devlist); 490 kfree(conf); 491} 492 493/* 494 * Is io distribute over 1 or more chunks ? 495*/ 496static inline int is_io_in_chunk_boundary(struct mddev *mddev, 497 unsigned int chunk_sects, struct bio *bio) 498{ 499 if (likely(is_power_of_2(chunk_sects))) { 500 return chunk_sects >= 501 ((bio->bi_iter.bi_sector & (chunk_sects-1)) 502 + bio_sectors(bio)); 503 } else{ 504 sector_t sector = bio->bi_iter.bi_sector; 505 return chunk_sects >= (sector_div(sector, chunk_sects) 506 + bio_sectors(bio)); 507 } 508} 509 510static void raid0_make_request(struct mddev *mddev, struct bio *bio) 511{ 512 struct strip_zone *zone; 513 struct md_rdev *tmp_dev; 514 struct bio *split; 515 516 if (unlikely(bio->bi_rw & REQ_FLUSH)) { 517 md_flush_request(mddev, bio); 518 return; 519 } 520 521 do { 522 sector_t sector = bio->bi_iter.bi_sector; 523 unsigned chunk_sects = mddev->chunk_sectors; 524 525 unsigned sectors = chunk_sects - 526 (likely(is_power_of_2(chunk_sects)) 527 ? (sector & (chunk_sects-1)) 528 : sector_div(sector, chunk_sects)); 529 530 /* Restore due to sector_div */ 531 sector = bio->bi_iter.bi_sector; 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 555static 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 561static 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 596static 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 637static 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 679static 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 716static void raid0_quiesce(struct mddev *mddev, int state) 717{ 718} 719 720static 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 .free = raid0_free, 728 .status = raid0_status, 729 .size = raid0_size, 730 .takeover = raid0_takeover, 731 .quiesce = raid0_quiesce, 732 .congested = raid0_congested, 733 .mergeable_bvec = raid0_mergeable_bvec, 734}; 735 736static int __init raid0_init (void) 737{ 738 return register_md_personality (&raid0_personality); 739} 740 741static void raid0_exit (void) 742{ 743 unregister_md_personality (&raid0_personality); 744} 745 746module_init(raid0_init); 747module_exit(raid0_exit); 748MODULE_LICENSE("GPL"); 749MODULE_DESCRIPTION("RAID0 (striping) personality for MD"); 750MODULE_ALIAS("md-personality-2"); /* RAID0 */ 751MODULE_ALIAS("md-raid0"); 752MODULE_ALIAS("md-level-0"); 753