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 9 RAID-0 management functions. 10 11 This program is free software; you can redistribute it and/or modify 12 it under the terms of the GNU General Public License as published by 13 the Free Software Foundation; either version 2, or (at your option) 14 any later version. 15 16 You should have received a copy of the GNU General Public License 17 (for example /usr/src/linux/COPYING); if not, write to the Free 18 Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 19 */ 20 21 #include <linux/blkdev.h> 22 #include <linux/seq_file.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 mddev_t *mddev = data; 31 raid0_conf_t *conf = mddev->private; 32 mdk_rdev_t **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(mddev_t *mddev) 51 { 52 int j, k, h; 53 sector_t zone_size = 0; 54 sector_t zone_start = 0; 55 char b[BDEVNAME_SIZE]; 56 raid0_conf_t *conf = mddev->private; 57 int raid_disks = conf->strip_zone[0].nb_dev; 58 printk(KERN_INFO "******* %s configuration *********\n", 59 mdname(mddev)); 60 h = 0; 61 for (j = 0; j < conf->nr_strip_zones; j++) { 62 printk(KERN_INFO "zone%d=[", j); 63 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 64 printk(KERN_CONT "%s/", 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=%llukb " 71 "device offset=%llukb size=%llukb\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\n"); 78 } 79 80 static int create_strip_zones(mddev_t *mddev, raid0_conf_t **private_conf) 81 { 82 int i, c, err; 83 sector_t curr_zone_end, sectors; 84 mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev, **dev; 85 struct strip_zone *zone; 86 int cnt; 87 char b[BDEVNAME_SIZE]; 88 raid0_conf_t *conf = kzalloc(sizeof(*conf), GFP_KERNEL); 89 90 if (!conf) 91 return -ENOMEM; 92 list_for_each_entry(rdev1, &mddev->disks, same_set) { 93 printk(KERN_INFO "md/raid0:%s: looking at %s\n", 94 mdname(mddev), 95 bdevname(rdev1->bdev, b)); 96 c = 0; 97 98 /* round size to chunk_size */ 99 sectors = rdev1->sectors; 100 sector_div(sectors, mddev->chunk_sectors); 101 rdev1->sectors = sectors * mddev->chunk_sectors; 102 103 list_for_each_entry(rdev2, &mddev->disks, same_set) { 104 printk(KERN_INFO "md/raid0:%s: comparing %s(%llu)", 105 mdname(mddev), 106 bdevname(rdev1->bdev,b), 107 (unsigned long long)rdev1->sectors); 108 printk(KERN_CONT " with %s(%llu)\n", 109 bdevname(rdev2->bdev,b), 110 (unsigned long long)rdev2->sectors); 111 if (rdev2 == rdev1) { 112 printk(KERN_INFO "md/raid0:%s: END\n", 113 mdname(mddev)); 114 break; 115 } 116 if (rdev2->sectors == rdev1->sectors) { 117 /* 118 * Not unique, don't count it as a new 119 * group 120 */ 121 printk(KERN_INFO "md/raid0:%s: EQUAL\n", 122 mdname(mddev)); 123 c = 1; 124 break; 125 } 126 printk(KERN_INFO "md/raid0:%s: NOT EQUAL\n", 127 mdname(mddev)); 128 } 129 if (!c) { 130 printk(KERN_INFO "md/raid0:%s: ==> UNIQUE\n", 131 mdname(mddev)); 132 conf->nr_strip_zones++; 133 printk(KERN_INFO "md/raid0:%s: %d zones\n", 134 mdname(mddev), conf->nr_strip_zones); 135 } 136 } 137 printk(KERN_INFO "md/raid0:%s: FINAL %d zones\n", 138 mdname(mddev), conf->nr_strip_zones); 139 err = -ENOMEM; 140 conf->strip_zone = kzalloc(sizeof(struct strip_zone)* 141 conf->nr_strip_zones, GFP_KERNEL); 142 if (!conf->strip_zone) 143 goto abort; 144 conf->devlist = kzalloc(sizeof(mdk_rdev_t*)* 145 conf->nr_strip_zones*mddev->raid_disks, 146 GFP_KERNEL); 147 if (!conf->devlist) 148 goto abort; 149 150 /* The first zone must contain all devices, so here we check that 151 * there is a proper alignment of slots to devices and find them all 152 */ 153 zone = &conf->strip_zone[0]; 154 cnt = 0; 155 smallest = NULL; 156 dev = conf->devlist; 157 err = -EINVAL; 158 list_for_each_entry(rdev1, &mddev->disks, same_set) { 159 int j = rdev1->raid_disk; 160 161 if (mddev->level == 10) { 162 /* taking over a raid10-n2 array */ 163 j /= 2; 164 rdev1->new_raid_disk = j; 165 } 166 167 if (mddev->level == 1) { 168 /* taiking over a raid1 array- 169 * we have only one active disk 170 */ 171 j = 0; 172 rdev1->new_raid_disk = j; 173 } 174 175 if (j < 0 || j >= mddev->raid_disks) { 176 printk(KERN_ERR "md/raid0:%s: bad disk number %d - " 177 "aborting!\n", mdname(mddev), j); 178 goto abort; 179 } 180 if (dev[j]) { 181 printk(KERN_ERR "md/raid0:%s: multiple devices for %d - " 182 "aborting!\n", mdname(mddev), j); 183 goto abort; 184 } 185 dev[j] = rdev1; 186 187 disk_stack_limits(mddev->gendisk, rdev1->bdev, 188 rdev1->data_offset << 9); 189 /* as we don't honour merge_bvec_fn, we must never risk 190 * violating it, so limit ->max_segments to 1, lying within 191 * a single page. 192 */ 193 194 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) { 195 blk_queue_max_segments(mddev->queue, 1); 196 blk_queue_segment_boundary(mddev->queue, 197 PAGE_CACHE_SIZE - 1); 198 } 199 if (!smallest || (rdev1->sectors < smallest->sectors)) 200 smallest = rdev1; 201 cnt++; 202 } 203 if (cnt != mddev->raid_disks) { 204 printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - " 205 "aborting!\n", 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 printk(KERN_INFO "md/raid0:%s: zone %d\n", 222 mdname(mddev), i); 223 zone->dev_start = smallest->sectors; 224 smallest = NULL; 225 c = 0; 226 227 for (j=0; j<cnt; j++) { 228 rdev = conf->devlist[j]; 229 printk(KERN_INFO "md/raid0:%s: checking %s ...", 230 mdname(mddev), 231 bdevname(rdev->bdev, b)); 232 if (rdev->sectors <= zone->dev_start) { 233 printk(KERN_CONT " nope.\n"); 234 continue; 235 } 236 printk(KERN_CONT " contained as device %d\n", c); 237 dev[c] = rdev; 238 c++; 239 if (!smallest || rdev->sectors < smallest->sectors) { 240 smallest = rdev; 241 printk(KERN_INFO "md/raid0:%s: (%llu) is smallest!.\n", 242 mdname(mddev), 243 (unsigned long long)rdev->sectors); 244 } 245 } 246 247 zone->nb_dev = c; 248 sectors = (smallest->sectors - zone->dev_start) * c; 249 printk(KERN_INFO "md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n", 250 mdname(mddev), 251 zone->nb_dev, (unsigned long long)sectors); 252 253 curr_zone_end += sectors; 254 zone->zone_end = curr_zone_end; 255 256 printk(KERN_INFO "md/raid0:%s: current zone start: %llu\n", 257 mdname(mddev), 258 (unsigned long long)smallest->sectors); 259 } 260 mddev->queue->backing_dev_info.congested_fn = raid0_congested; 261 mddev->queue->backing_dev_info.congested_data = mddev; 262 263 /* 264 * now since we have the hard sector sizes, we can make sure 265 * chunk size is a multiple of that sector size 266 */ 267 if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) { 268 printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n", 269 mdname(mddev), 270 mddev->chunk_sectors << 9); 271 goto abort; 272 } 273 274 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9); 275 blk_queue_io_opt(mddev->queue, 276 (mddev->chunk_sectors << 9) * mddev->raid_disks); 277 278 printk(KERN_INFO "md/raid0:%s: done.\n", mdname(mddev)); 279 *private_conf = conf; 280 281 return 0; 282 abort: 283 kfree(conf->strip_zone); 284 kfree(conf->devlist); 285 kfree(conf); 286 *private_conf = NULL; 287 return err; 288 } 289 290 /** 291 * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged 292 * @q: request queue 293 * @bvm: properties of new bio 294 * @biovec: the request that could be merged to it. 295 * 296 * Return amount of bytes we can accept at this offset 297 */ 298 static int raid0_mergeable_bvec(struct request_queue *q, 299 struct bvec_merge_data *bvm, 300 struct bio_vec *biovec) 301 { 302 mddev_t *mddev = q->queuedata; 303 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); 304 int max; 305 unsigned int chunk_sectors = mddev->chunk_sectors; 306 unsigned int bio_sectors = bvm->bi_size >> 9; 307 308 if (is_power_of_2(chunk_sectors)) 309 max = (chunk_sectors - ((sector & (chunk_sectors-1)) 310 + bio_sectors)) << 9; 311 else 312 max = (chunk_sectors - (sector_div(sector, chunk_sectors) 313 + bio_sectors)) << 9; 314 if (max < 0) max = 0; /* bio_add cannot handle a negative return */ 315 if (max <= biovec->bv_len && bio_sectors == 0) 316 return biovec->bv_len; 317 else 318 return max; 319 } 320 321 static sector_t raid0_size(mddev_t *mddev, sector_t sectors, int raid_disks) 322 { 323 sector_t array_sectors = 0; 324 mdk_rdev_t *rdev; 325 326 WARN_ONCE(sectors || raid_disks, 327 "%s does not support generic reshape\n", __func__); 328 329 list_for_each_entry(rdev, &mddev->disks, same_set) 330 array_sectors += rdev->sectors; 331 332 return array_sectors; 333 } 334 335 static int raid0_run(mddev_t *mddev) 336 { 337 raid0_conf_t *conf; 338 int ret; 339 340 if (mddev->chunk_sectors == 0) { 341 printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n", 342 mdname(mddev)); 343 return -EINVAL; 344 } 345 if (md_check_no_bitmap(mddev)) 346 return -EINVAL; 347 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); 348 349 /* if private is not null, we are here after takeover */ 350 if (mddev->private == NULL) { 351 ret = create_strip_zones(mddev, &conf); 352 if (ret < 0) 353 return ret; 354 mddev->private = conf; 355 } 356 conf = mddev->private; 357 358 /* calculate array device size */ 359 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); 360 361 printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n", 362 mdname(mddev), 363 (unsigned long long)mddev->array_sectors); 364 /* calculate the max read-ahead size. 365 * For read-ahead of large files to be effective, we need to 366 * readahead at least twice a whole stripe. i.e. number of devices 367 * multiplied by chunk size times 2. 368 * If an individual device has an ra_pages greater than the 369 * chunk size, then we will not drive that device as hard as it 370 * wants. We consider this a configuration error: a larger 371 * chunksize should be used in that case. 372 */ 373 { 374 int stripe = mddev->raid_disks * 375 (mddev->chunk_sectors << 9) / PAGE_SIZE; 376 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) 377 mddev->queue->backing_dev_info.ra_pages = 2* stripe; 378 } 379 380 blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec); 381 dump_zones(mddev); 382 return md_integrity_register(mddev); 383 } 384 385 static int raid0_stop(mddev_t *mddev) 386 { 387 raid0_conf_t *conf = mddev->private; 388 389 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 390 kfree(conf->strip_zone); 391 kfree(conf->devlist); 392 kfree(conf); 393 mddev->private = NULL; 394 return 0; 395 } 396 397 /* Find the zone which holds a particular offset 398 * Update *sectorp to be an offset in that zone 399 */ 400 static struct strip_zone *find_zone(struct raid0_private_data *conf, 401 sector_t *sectorp) 402 { 403 int i; 404 struct strip_zone *z = conf->strip_zone; 405 sector_t sector = *sectorp; 406 407 for (i = 0; i < conf->nr_strip_zones; i++) 408 if (sector < z[i].zone_end) { 409 if (i) 410 *sectorp = sector - z[i-1].zone_end; 411 return z + i; 412 } 413 BUG(); 414 } 415 416 /* 417 * remaps the bio to the target device. we separate two flows. 418 * power 2 flow and a general flow for the sake of perfromance 419 */ 420 static mdk_rdev_t *map_sector(mddev_t *mddev, struct strip_zone *zone, 421 sector_t sector, sector_t *sector_offset) 422 { 423 unsigned int sect_in_chunk; 424 sector_t chunk; 425 raid0_conf_t *conf = mddev->private; 426 int raid_disks = conf->strip_zone[0].nb_dev; 427 unsigned int chunk_sects = mddev->chunk_sectors; 428 429 if (is_power_of_2(chunk_sects)) { 430 int chunksect_bits = ffz(~chunk_sects); 431 /* find the sector offset inside the chunk */ 432 sect_in_chunk = sector & (chunk_sects - 1); 433 sector >>= chunksect_bits; 434 /* chunk in zone */ 435 chunk = *sector_offset; 436 /* quotient is the chunk in real device*/ 437 sector_div(chunk, zone->nb_dev << chunksect_bits); 438 } else{ 439 sect_in_chunk = sector_div(sector, chunk_sects); 440 chunk = *sector_offset; 441 sector_div(chunk, chunk_sects * zone->nb_dev); 442 } 443 /* 444 * position the bio over the real device 445 * real sector = chunk in device + starting of zone 446 * + the position in the chunk 447 */ 448 *sector_offset = (chunk * chunk_sects) + sect_in_chunk; 449 return conf->devlist[(zone - conf->strip_zone)*raid_disks 450 + sector_div(sector, zone->nb_dev)]; 451 } 452 453 /* 454 * Is io distribute over 1 or more chunks ? 455 */ 456 static inline int is_io_in_chunk_boundary(mddev_t *mddev, 457 unsigned int chunk_sects, struct bio *bio) 458 { 459 if (likely(is_power_of_2(chunk_sects))) { 460 return chunk_sects >= ((bio->bi_sector & (chunk_sects-1)) 461 + (bio->bi_size >> 9)); 462 } else{ 463 sector_t sector = bio->bi_sector; 464 return chunk_sects >= (sector_div(sector, chunk_sects) 465 + (bio->bi_size >> 9)); 466 } 467 } 468 469 static int raid0_make_request(mddev_t *mddev, struct bio *bio) 470 { 471 unsigned int chunk_sects; 472 sector_t sector_offset; 473 struct strip_zone *zone; 474 mdk_rdev_t *tmp_dev; 475 476 if (unlikely(bio->bi_rw & REQ_FLUSH)) { 477 md_flush_request(mddev, bio); 478 return 0; 479 } 480 481 chunk_sects = mddev->chunk_sectors; 482 if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) { 483 sector_t sector = bio->bi_sector; 484 struct bio_pair *bp; 485 /* Sanity check -- queue functions should prevent this happening */ 486 if (bio->bi_vcnt != 1 || 487 bio->bi_idx != 0) 488 goto bad_map; 489 /* This is a one page bio that upper layers 490 * refuse to split for us, so we need to split it. 491 */ 492 if (likely(is_power_of_2(chunk_sects))) 493 bp = bio_split(bio, chunk_sects - (sector & 494 (chunk_sects-1))); 495 else 496 bp = bio_split(bio, chunk_sects - 497 sector_div(sector, chunk_sects)); 498 if (raid0_make_request(mddev, &bp->bio1)) 499 generic_make_request(&bp->bio1); 500 if (raid0_make_request(mddev, &bp->bio2)) 501 generic_make_request(&bp->bio2); 502 503 bio_pair_release(bp); 504 return 0; 505 } 506 507 sector_offset = bio->bi_sector; 508 zone = find_zone(mddev->private, §or_offset); 509 tmp_dev = map_sector(mddev, zone, bio->bi_sector, 510 §or_offset); 511 bio->bi_bdev = tmp_dev->bdev; 512 bio->bi_sector = sector_offset + zone->dev_start + 513 tmp_dev->data_offset; 514 /* 515 * Let the main block layer submit the IO and resolve recursion: 516 */ 517 return 1; 518 519 bad_map: 520 printk("md/raid0:%s: make_request bug: can't convert block across chunks" 521 " or bigger than %dk %llu %d\n", 522 mdname(mddev), chunk_sects / 2, 523 (unsigned long long)bio->bi_sector, bio->bi_size >> 10); 524 525 bio_io_error(bio); 526 return 0; 527 } 528 529 static void raid0_status(struct seq_file *seq, mddev_t *mddev) 530 { 531 #undef MD_DEBUG 532 #ifdef MD_DEBUG 533 int j, k, h; 534 char b[BDEVNAME_SIZE]; 535 raid0_conf_t *conf = mddev->private; 536 int raid_disks = conf->strip_zone[0].nb_dev; 537 538 sector_t zone_size; 539 sector_t zone_start = 0; 540 h = 0; 541 542 for (j = 0; j < conf->nr_strip_zones; j++) { 543 seq_printf(seq, " z%d", j); 544 seq_printf(seq, "=["); 545 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 546 seq_printf(seq, "%s/", bdevname( 547 conf->devlist[j*raid_disks + k] 548 ->bdev, b)); 549 550 zone_size = conf->strip_zone[j].zone_end - zone_start; 551 seq_printf(seq, "] ze=%lld ds=%lld s=%lld\n", 552 (unsigned long long)zone_start>>1, 553 (unsigned long long)conf->strip_zone[j].dev_start>>1, 554 (unsigned long long)zone_size>>1); 555 zone_start = conf->strip_zone[j].zone_end; 556 } 557 #endif 558 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2); 559 return; 560 } 561 562 static void *raid0_takeover_raid45(mddev_t *mddev) 563 { 564 mdk_rdev_t *rdev; 565 raid0_conf_t *priv_conf; 566 567 if (mddev->degraded != 1) { 568 printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n", 569 mdname(mddev), 570 mddev->degraded); 571 return ERR_PTR(-EINVAL); 572 } 573 574 list_for_each_entry(rdev, &mddev->disks, same_set) { 575 /* check slot number for a disk */ 576 if (rdev->raid_disk == mddev->raid_disks-1) { 577 printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n", 578 mdname(mddev)); 579 return ERR_PTR(-EINVAL); 580 } 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(mddev_t *mddev) 597 { 598 raid0_conf_t *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(mddev_t *mddev) 638 { 639 raid0_conf_t *priv_conf; 640 641 /* Check layout: 642 * - (N - 1) mirror drives must be already faulty 643 */ 644 if ((mddev->raid_disks - 1) != mddev->degraded) { 645 printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n", 646 mdname(mddev)); 647 return ERR_PTR(-EINVAL); 648 } 649 650 /* Set new parameters */ 651 mddev->new_level = 0; 652 mddev->new_layout = 0; 653 mddev->new_chunk_sectors = 128; /* by default set chunk size to 64k */ 654 mddev->delta_disks = 1 - mddev->raid_disks; 655 mddev->raid_disks = 1; 656 /* make sure it will be not marked as dirty */ 657 mddev->recovery_cp = MaxSector; 658 659 create_strip_zones(mddev, &priv_conf); 660 return priv_conf; 661 } 662 663 static void *raid0_takeover(mddev_t *mddev) 664 { 665 /* raid0 can take over: 666 * raid4 - if all data disks are active. 667 * raid5 - providing it is Raid4 layout and one disk is faulty 668 * raid10 - assuming we have all necessary active disks 669 * raid1 - with (N -1) mirror drives faulty 670 */ 671 if (mddev->level == 4) 672 return raid0_takeover_raid45(mddev); 673 674 if (mddev->level == 5) { 675 if (mddev->layout == ALGORITHM_PARITY_N) 676 return raid0_takeover_raid45(mddev); 677 678 printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n", 679 mdname(mddev), ALGORITHM_PARITY_N); 680 } 681 682 if (mddev->level == 10) 683 return raid0_takeover_raid10(mddev); 684 685 if (mddev->level == 1) 686 return raid0_takeover_raid1(mddev); 687 688 printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n", 689 mddev->level); 690 691 return ERR_PTR(-EINVAL); 692 } 693 694 static void raid0_quiesce(mddev_t *mddev, int state) 695 { 696 } 697 698 static struct mdk_personality raid0_personality= 699 { 700 .name = "raid0", 701 .level = 0, 702 .owner = THIS_MODULE, 703 .make_request = raid0_make_request, 704 .run = raid0_run, 705 .stop = raid0_stop, 706 .status = raid0_status, 707 .size = raid0_size, 708 .takeover = raid0_takeover, 709 .quiesce = raid0_quiesce, 710 }; 711 712 static int __init raid0_init (void) 713 { 714 return register_md_personality (&raid0_personality); 715 } 716 717 static void raid0_exit (void) 718 { 719 unregister_md_personality (&raid0_personality); 720 } 721 722 module_init(raid0_init); 723 module_exit(raid0_exit); 724 MODULE_LICENSE("GPL"); 725 MODULE_DESCRIPTION("RAID0 (striping) personality for MD"); 726 MODULE_ALIAS("md-personality-2"); /* RAID0 */ 727 MODULE_ALIAS("md-raid0"); 728 MODULE_ALIAS("md-level-0"); 729