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/module.h> 24 #include <linux/slab.h> 25 #include "md.h" 26 #include "raid0.h" 27 #include "raid5.h" 28 29 static int raid0_congested(void *data, int bits) 30 { 31 struct mddev *mddev = data; 32 struct r0conf *conf = mddev->private; 33 struct md_rdev **devlist = conf->devlist; 34 int raid_disks = conf->strip_zone[0].nb_dev; 35 int i, ret = 0; 36 37 if (mddev_congested(mddev, bits)) 38 return 1; 39 40 for (i = 0; i < raid_disks && !ret ; i++) { 41 struct request_queue *q = bdev_get_queue(devlist[i]->bdev); 42 43 ret |= bdi_congested(&q->backing_dev_info, bits); 44 } 45 return ret; 46 } 47 48 /* 49 * inform the user of the raid configuration 50 */ 51 static void dump_zones(struct mddev *mddev) 52 { 53 int j, k; 54 sector_t zone_size = 0; 55 sector_t zone_start = 0; 56 char b[BDEVNAME_SIZE]; 57 struct r0conf *conf = mddev->private; 58 int raid_disks = conf->strip_zone[0].nb_dev; 59 printk(KERN_INFO "md: RAID0 configuration for %s - %d zone%s\n", 60 mdname(mddev), 61 conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s"); 62 for (j = 0; j < conf->nr_strip_zones; j++) { 63 printk(KERN_INFO "md: zone%d=[", j); 64 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 65 printk(KERN_CONT "%s%s", k?"/":"", 66 bdevname(conf->devlist[j*raid_disks 67 + k]->bdev, b)); 68 printk(KERN_CONT "]\n"); 69 70 zone_size = conf->strip_zone[j].zone_end - zone_start; 71 printk(KERN_INFO " zone-offset=%10lluKB, " 72 "device-offset=%10lluKB, size=%10lluKB\n", 73 (unsigned long long)zone_start>>1, 74 (unsigned long long)conf->strip_zone[j].dev_start>>1, 75 (unsigned long long)zone_size>>1); 76 zone_start = conf->strip_zone[j].zone_end; 77 } 78 printk(KERN_INFO "\n"); 79 } 80 81 static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) 82 { 83 int i, c, err; 84 sector_t curr_zone_end, sectors; 85 struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev; 86 struct strip_zone *zone; 87 int cnt; 88 char b[BDEVNAME_SIZE]; 89 char b2[BDEVNAME_SIZE]; 90 struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL); 91 bool discard_supported = false; 92 93 if (!conf) 94 return -ENOMEM; 95 rdev_for_each(rdev1, mddev) { 96 pr_debug("md/raid0:%s: looking at %s\n", 97 mdname(mddev), 98 bdevname(rdev1->bdev, b)); 99 c = 0; 100 101 /* round size to chunk_size */ 102 sectors = rdev1->sectors; 103 sector_div(sectors, mddev->chunk_sectors); 104 rdev1->sectors = sectors * mddev->chunk_sectors; 105 106 rdev_for_each(rdev2, mddev) { 107 pr_debug("md/raid0:%s: comparing %s(%llu)" 108 " with %s(%llu)\n", 109 mdname(mddev), 110 bdevname(rdev1->bdev,b), 111 (unsigned long long)rdev1->sectors, 112 bdevname(rdev2->bdev,b2), 113 (unsigned long long)rdev2->sectors); 114 if (rdev2 == rdev1) { 115 pr_debug("md/raid0:%s: END\n", 116 mdname(mddev)); 117 break; 118 } 119 if (rdev2->sectors == rdev1->sectors) { 120 /* 121 * Not unique, don't count it as a new 122 * group 123 */ 124 pr_debug("md/raid0:%s: EQUAL\n", 125 mdname(mddev)); 126 c = 1; 127 break; 128 } 129 pr_debug("md/raid0:%s: NOT EQUAL\n", 130 mdname(mddev)); 131 } 132 if (!c) { 133 pr_debug("md/raid0:%s: ==> UNIQUE\n", 134 mdname(mddev)); 135 conf->nr_strip_zones++; 136 pr_debug("md/raid0:%s: %d zones\n", 137 mdname(mddev), conf->nr_strip_zones); 138 } 139 } 140 pr_debug("md/raid0:%s: FINAL %d zones\n", 141 mdname(mddev), conf->nr_strip_zones); 142 err = -ENOMEM; 143 conf->strip_zone = kzalloc(sizeof(struct strip_zone)* 144 conf->nr_strip_zones, GFP_KERNEL); 145 if (!conf->strip_zone) 146 goto abort; 147 conf->devlist = kzalloc(sizeof(struct md_rdev*)* 148 conf->nr_strip_zones*mddev->raid_disks, 149 GFP_KERNEL); 150 if (!conf->devlist) 151 goto abort; 152 153 /* The first zone must contain all devices, so here we check that 154 * there is a proper alignment of slots to devices and find them all 155 */ 156 zone = &conf->strip_zone[0]; 157 cnt = 0; 158 smallest = NULL; 159 dev = conf->devlist; 160 err = -EINVAL; 161 rdev_for_each(rdev1, mddev) { 162 int j = rdev1->raid_disk; 163 164 if (mddev->level == 10) { 165 /* taking over a raid10-n2 array */ 166 j /= 2; 167 rdev1->new_raid_disk = j; 168 } 169 170 if (mddev->level == 1) { 171 /* taiking over a raid1 array- 172 * we have only one active disk 173 */ 174 j = 0; 175 rdev1->new_raid_disk = j; 176 } 177 178 if (j < 0) { 179 printk(KERN_ERR 180 "md/raid0:%s: remove inactive devices before converting to RAID0\n", 181 mdname(mddev)); 182 goto abort; 183 } 184 if (j >= mddev->raid_disks) { 185 printk(KERN_ERR "md/raid0:%s: bad disk number %d - " 186 "aborting!\n", mdname(mddev), j); 187 goto abort; 188 } 189 if (dev[j]) { 190 printk(KERN_ERR "md/raid0:%s: multiple devices for %d - " 191 "aborting!\n", mdname(mddev), j); 192 goto abort; 193 } 194 dev[j] = rdev1; 195 196 disk_stack_limits(mddev->gendisk, rdev1->bdev, 197 rdev1->data_offset << 9); 198 199 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) 200 conf->has_merge_bvec = 1; 201 202 if (!smallest || (rdev1->sectors < smallest->sectors)) 203 smallest = rdev1; 204 cnt++; 205 206 if (blk_queue_discard(bdev_get_queue(rdev1->bdev))) 207 discard_supported = true; 208 } 209 if (cnt != mddev->raid_disks) { 210 printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - " 211 "aborting!\n", mdname(mddev), cnt, mddev->raid_disks); 212 goto abort; 213 } 214 zone->nb_dev = cnt; 215 zone->zone_end = smallest->sectors * cnt; 216 217 curr_zone_end = zone->zone_end; 218 219 /* now do the other zones */ 220 for (i = 1; i < conf->nr_strip_zones; i++) 221 { 222 int j; 223 224 zone = conf->strip_zone + i; 225 dev = conf->devlist + i * mddev->raid_disks; 226 227 pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i); 228 zone->dev_start = smallest->sectors; 229 smallest = NULL; 230 c = 0; 231 232 for (j=0; j<cnt; j++) { 233 rdev = conf->devlist[j]; 234 if (rdev->sectors <= zone->dev_start) { 235 pr_debug("md/raid0:%s: checking %s ... nope\n", 236 mdname(mddev), 237 bdevname(rdev->bdev, b)); 238 continue; 239 } 240 pr_debug("md/raid0:%s: checking %s ..." 241 " contained as device %d\n", 242 mdname(mddev), 243 bdevname(rdev->bdev, b), c); 244 dev[c] = rdev; 245 c++; 246 if (!smallest || rdev->sectors < smallest->sectors) { 247 smallest = rdev; 248 pr_debug("md/raid0:%s: (%llu) is smallest!.\n", 249 mdname(mddev), 250 (unsigned long long)rdev->sectors); 251 } 252 } 253 254 zone->nb_dev = c; 255 sectors = (smallest->sectors - zone->dev_start) * c; 256 pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n", 257 mdname(mddev), 258 zone->nb_dev, (unsigned long long)sectors); 259 260 curr_zone_end += sectors; 261 zone->zone_end = curr_zone_end; 262 263 pr_debug("md/raid0:%s: current zone start: %llu\n", 264 mdname(mddev), 265 (unsigned long long)smallest->sectors); 266 } 267 mddev->queue->backing_dev_info.congested_fn = raid0_congested; 268 mddev->queue->backing_dev_info.congested_data = mddev; 269 270 /* 271 * now since we have the hard sector sizes, we can make sure 272 * chunk size is a multiple of that sector size 273 */ 274 if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) { 275 printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n", 276 mdname(mddev), 277 mddev->chunk_sectors << 9); 278 goto abort; 279 } 280 281 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9); 282 blk_queue_io_opt(mddev->queue, 283 (mddev->chunk_sectors << 9) * mddev->raid_disks); 284 285 if (!discard_supported) 286 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 287 else 288 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); 289 290 pr_debug("md/raid0:%s: done.\n", mdname(mddev)); 291 *private_conf = conf; 292 293 return 0; 294 abort: 295 kfree(conf->strip_zone); 296 kfree(conf->devlist); 297 kfree(conf); 298 *private_conf = ERR_PTR(err); 299 return err; 300 } 301 302 /* Find the zone which holds a particular offset 303 * Update *sectorp to be an offset in that zone 304 */ 305 static struct strip_zone *find_zone(struct r0conf *conf, 306 sector_t *sectorp) 307 { 308 int i; 309 struct strip_zone *z = conf->strip_zone; 310 sector_t sector = *sectorp; 311 312 for (i = 0; i < conf->nr_strip_zones; i++) 313 if (sector < z[i].zone_end) { 314 if (i) 315 *sectorp = sector - z[i-1].zone_end; 316 return z + i; 317 } 318 BUG(); 319 } 320 321 /* 322 * remaps the bio to the target device. we separate two flows. 323 * power 2 flow and a general flow for the sake of perfromance 324 */ 325 static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone, 326 sector_t sector, sector_t *sector_offset) 327 { 328 unsigned int sect_in_chunk; 329 sector_t chunk; 330 struct r0conf *conf = mddev->private; 331 int raid_disks = conf->strip_zone[0].nb_dev; 332 unsigned int chunk_sects = mddev->chunk_sectors; 333 334 if (is_power_of_2(chunk_sects)) { 335 int chunksect_bits = ffz(~chunk_sects); 336 /* find the sector offset inside the chunk */ 337 sect_in_chunk = sector & (chunk_sects - 1); 338 sector >>= chunksect_bits; 339 /* chunk in zone */ 340 chunk = *sector_offset; 341 /* quotient is the chunk in real device*/ 342 sector_div(chunk, zone->nb_dev << chunksect_bits); 343 } else{ 344 sect_in_chunk = sector_div(sector, chunk_sects); 345 chunk = *sector_offset; 346 sector_div(chunk, chunk_sects * zone->nb_dev); 347 } 348 /* 349 * position the bio over the real device 350 * real sector = chunk in device + starting of zone 351 * + the position in the chunk 352 */ 353 *sector_offset = (chunk * chunk_sects) + sect_in_chunk; 354 return conf->devlist[(zone - conf->strip_zone)*raid_disks 355 + sector_div(sector, zone->nb_dev)]; 356 } 357 358 /** 359 * raid0_mergeable_bvec -- tell bio layer if two requests can be merged 360 * @q: request queue 361 * @bvm: properties of new bio 362 * @biovec: the request that could be merged to it. 363 * 364 * Return amount of bytes we can accept at this offset 365 */ 366 static int raid0_mergeable_bvec(struct request_queue *q, 367 struct bvec_merge_data *bvm, 368 struct bio_vec *biovec) 369 { 370 struct mddev *mddev = q->queuedata; 371 struct r0conf *conf = mddev->private; 372 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); 373 sector_t sector_offset = sector; 374 int max; 375 unsigned int chunk_sectors = mddev->chunk_sectors; 376 unsigned int bio_sectors = bvm->bi_size >> 9; 377 struct strip_zone *zone; 378 struct md_rdev *rdev; 379 struct request_queue *subq; 380 381 if (is_power_of_2(chunk_sectors)) 382 max = (chunk_sectors - ((sector & (chunk_sectors-1)) 383 + bio_sectors)) << 9; 384 else 385 max = (chunk_sectors - (sector_div(sector, chunk_sectors) 386 + bio_sectors)) << 9; 387 if (max < 0) 388 max = 0; /* bio_add cannot handle a negative return */ 389 if (max <= biovec->bv_len && bio_sectors == 0) 390 return biovec->bv_len; 391 if (max < biovec->bv_len) 392 /* too small already, no need to check further */ 393 return max; 394 if (!conf->has_merge_bvec) 395 return max; 396 397 /* May need to check subordinate device */ 398 sector = sector_offset; 399 zone = find_zone(mddev->private, §or_offset); 400 rdev = map_sector(mddev, zone, sector, §or_offset); 401 subq = bdev_get_queue(rdev->bdev); 402 if (subq->merge_bvec_fn) { 403 bvm->bi_bdev = rdev->bdev; 404 bvm->bi_sector = sector_offset + zone->dev_start + 405 rdev->data_offset; 406 return min(max, subq->merge_bvec_fn(subq, bvm, biovec)); 407 } else 408 return max; 409 } 410 411 static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks) 412 { 413 sector_t array_sectors = 0; 414 struct md_rdev *rdev; 415 416 WARN_ONCE(sectors || raid_disks, 417 "%s does not support generic reshape\n", __func__); 418 419 rdev_for_each(rdev, mddev) 420 array_sectors += (rdev->sectors & 421 ~(sector_t)(mddev->chunk_sectors-1)); 422 423 return array_sectors; 424 } 425 426 static int raid0_stop(struct mddev *mddev); 427 428 static int raid0_run(struct mddev *mddev) 429 { 430 struct r0conf *conf; 431 int ret; 432 433 if (mddev->chunk_sectors == 0) { 434 printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n", 435 mdname(mddev)); 436 return -EINVAL; 437 } 438 if (md_check_no_bitmap(mddev)) 439 return -EINVAL; 440 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); 441 blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors); 442 blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors); 443 444 /* if private is not null, we are here after takeover */ 445 if (mddev->private == NULL) { 446 ret = create_strip_zones(mddev, &conf); 447 if (ret < 0) 448 return ret; 449 mddev->private = conf; 450 } 451 conf = mddev->private; 452 453 /* calculate array device size */ 454 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); 455 456 printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n", 457 mdname(mddev), 458 (unsigned long long)mddev->array_sectors); 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 { 469 int stripe = mddev->raid_disks * 470 (mddev->chunk_sectors << 9) / PAGE_SIZE; 471 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) 472 mddev->queue->backing_dev_info.ra_pages = 2* stripe; 473 } 474 475 blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec); 476 dump_zones(mddev); 477 478 ret = md_integrity_register(mddev); 479 if (ret) 480 raid0_stop(mddev); 481 482 return ret; 483 } 484 485 static int raid0_stop(struct mddev *mddev) 486 { 487 struct r0conf *conf = mddev->private; 488 489 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 490 kfree(conf->strip_zone); 491 kfree(conf->devlist); 492 kfree(conf); 493 mddev->private = NULL; 494 return 0; 495 } 496 497 /* 498 * Is io distribute over 1 or more chunks ? 499 */ 500 static inline int is_io_in_chunk_boundary(struct mddev *mddev, 501 unsigned int chunk_sects, struct bio *bio) 502 { 503 if (likely(is_power_of_2(chunk_sects))) { 504 return chunk_sects >= ((bio->bi_sector & (chunk_sects-1)) 505 + bio_sectors(bio)); 506 } else{ 507 sector_t sector = bio->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 unsigned int chunk_sects; 516 sector_t sector_offset; 517 struct strip_zone *zone; 518 struct md_rdev *tmp_dev; 519 520 if (unlikely(bio->bi_rw & REQ_FLUSH)) { 521 md_flush_request(mddev, bio); 522 return; 523 } 524 525 chunk_sects = mddev->chunk_sectors; 526 if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) { 527 sector_t sector = bio->bi_sector; 528 struct bio_pair *bp; 529 /* Sanity check -- queue functions should prevent this happening */ 530 if (bio_segments(bio) > 1) 531 goto bad_map; 532 /* This is a one page bio that upper layers 533 * refuse to split for us, so we need to split it. 534 */ 535 if (likely(is_power_of_2(chunk_sects))) 536 bp = bio_split(bio, chunk_sects - (sector & 537 (chunk_sects-1))); 538 else 539 bp = bio_split(bio, chunk_sects - 540 sector_div(sector, chunk_sects)); 541 raid0_make_request(mddev, &bp->bio1); 542 raid0_make_request(mddev, &bp->bio2); 543 bio_pair_release(bp); 544 return; 545 } 546 547 sector_offset = bio->bi_sector; 548 zone = find_zone(mddev->private, §or_offset); 549 tmp_dev = map_sector(mddev, zone, bio->bi_sector, 550 §or_offset); 551 bio->bi_bdev = tmp_dev->bdev; 552 bio->bi_sector = sector_offset + zone->dev_start + 553 tmp_dev->data_offset; 554 555 if (unlikely((bio->bi_rw & REQ_DISCARD) && 556 !blk_queue_discard(bdev_get_queue(bio->bi_bdev)))) { 557 /* Just ignore it */ 558 bio_endio(bio, 0); 559 return; 560 } 561 562 generic_make_request(bio); 563 return; 564 565 bad_map: 566 printk("md/raid0:%s: make_request bug: can't convert block across chunks" 567 " or bigger than %dk %llu %d\n", 568 mdname(mddev), chunk_sects / 2, 569 (unsigned long long)bio->bi_sector, bio_sectors(bio) / 2); 570 571 bio_io_error(bio); 572 return; 573 } 574 575 static void raid0_status(struct seq_file *seq, struct mddev *mddev) 576 { 577 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2); 578 return; 579 } 580 581 static void *raid0_takeover_raid45(struct mddev *mddev) 582 { 583 struct md_rdev *rdev; 584 struct r0conf *priv_conf; 585 586 if (mddev->degraded != 1) { 587 printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n", 588 mdname(mddev), 589 mddev->degraded); 590 return ERR_PTR(-EINVAL); 591 } 592 593 rdev_for_each(rdev, mddev) { 594 /* check slot number for a disk */ 595 if (rdev->raid_disk == mddev->raid_disks-1) { 596 printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n", 597 mdname(mddev)); 598 return ERR_PTR(-EINVAL); 599 } 600 rdev->sectors = mddev->dev_sectors; 601 } 602 603 /* Set new parameters */ 604 mddev->new_level = 0; 605 mddev->new_layout = 0; 606 mddev->new_chunk_sectors = mddev->chunk_sectors; 607 mddev->raid_disks--; 608 mddev->delta_disks = -1; 609 /* make sure it will be not marked as dirty */ 610 mddev->recovery_cp = MaxSector; 611 612 create_strip_zones(mddev, &priv_conf); 613 return priv_conf; 614 } 615 616 static void *raid0_takeover_raid10(struct mddev *mddev) 617 { 618 struct r0conf *priv_conf; 619 620 /* Check layout: 621 * - far_copies must be 1 622 * - near_copies must be 2 623 * - disks number must be even 624 * - all mirrors must be already degraded 625 */ 626 if (mddev->layout != ((1 << 8) + 2)) { 627 printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takover layout: 0x%x\n", 628 mdname(mddev), 629 mddev->layout); 630 return ERR_PTR(-EINVAL); 631 } 632 if (mddev->raid_disks & 1) { 633 printk(KERN_ERR "md/raid0:%s: Raid0 cannot takover Raid10 with odd disk number.\n", 634 mdname(mddev)); 635 return ERR_PTR(-EINVAL); 636 } 637 if (mddev->degraded != (mddev->raid_disks>>1)) { 638 printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n", 639 mdname(mddev)); 640 return ERR_PTR(-EINVAL); 641 } 642 643 /* Set new parameters */ 644 mddev->new_level = 0; 645 mddev->new_layout = 0; 646 mddev->new_chunk_sectors = mddev->chunk_sectors; 647 mddev->delta_disks = - mddev->raid_disks / 2; 648 mddev->raid_disks += mddev->delta_disks; 649 mddev->degraded = 0; 650 /* make sure it will be not marked as dirty */ 651 mddev->recovery_cp = MaxSector; 652 653 create_strip_zones(mddev, &priv_conf); 654 return priv_conf; 655 } 656 657 static void *raid0_takeover_raid1(struct mddev *mddev) 658 { 659 struct r0conf *priv_conf; 660 int chunksect; 661 662 /* Check layout: 663 * - (N - 1) mirror drives must be already faulty 664 */ 665 if ((mddev->raid_disks - 1) != mddev->degraded) { 666 printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n", 667 mdname(mddev)); 668 return ERR_PTR(-EINVAL); 669 } 670 671 /* 672 * a raid1 doesn't have the notion of chunk size, so 673 * figure out the largest suitable size we can use. 674 */ 675 chunksect = 64 * 2; /* 64K by default */ 676 677 /* The array must be an exact multiple of chunksize */ 678 while (chunksect && (mddev->array_sectors & (chunksect - 1))) 679 chunksect >>= 1; 680 681 if ((chunksect << 9) < PAGE_SIZE) 682 /* array size does not allow a suitable chunk size */ 683 return ERR_PTR(-EINVAL); 684 685 /* Set new parameters */ 686 mddev->new_level = 0; 687 mddev->new_layout = 0; 688 mddev->new_chunk_sectors = chunksect; 689 mddev->chunk_sectors = chunksect; 690 mddev->delta_disks = 1 - mddev->raid_disks; 691 mddev->raid_disks = 1; 692 /* make sure it will be not marked as dirty */ 693 mddev->recovery_cp = MaxSector; 694 695 create_strip_zones(mddev, &priv_conf); 696 return priv_conf; 697 } 698 699 static void *raid0_takeover(struct mddev *mddev) 700 { 701 /* raid0 can take over: 702 * raid4 - if all data disks are active. 703 * raid5 - providing it is Raid4 layout and one disk is faulty 704 * raid10 - assuming we have all necessary active disks 705 * raid1 - with (N -1) mirror drives faulty 706 */ 707 if (mddev->level == 4) 708 return raid0_takeover_raid45(mddev); 709 710 if (mddev->level == 5) { 711 if (mddev->layout == ALGORITHM_PARITY_N) 712 return raid0_takeover_raid45(mddev); 713 714 printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n", 715 mdname(mddev), ALGORITHM_PARITY_N); 716 } 717 718 if (mddev->level == 10) 719 return raid0_takeover_raid10(mddev); 720 721 if (mddev->level == 1) 722 return raid0_takeover_raid1(mddev); 723 724 printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n", 725 mddev->level); 726 727 return ERR_PTR(-EINVAL); 728 } 729 730 static void raid0_quiesce(struct mddev *mddev, int state) 731 { 732 } 733 734 static struct md_personality raid0_personality= 735 { 736 .name = "raid0", 737 .level = 0, 738 .owner = THIS_MODULE, 739 .make_request = raid0_make_request, 740 .run = raid0_run, 741 .stop = raid0_stop, 742 .status = raid0_status, 743 .size = raid0_size, 744 .takeover = raid0_takeover, 745 .quiesce = raid0_quiesce, 746 }; 747 748 static int __init raid0_init (void) 749 { 750 return register_md_personality (&raid0_personality); 751 } 752 753 static void raid0_exit (void) 754 { 755 unregister_md_personality (&raid0_personality); 756 } 757 758 module_init(raid0_init); 759 module_exit(raid0_exit); 760 MODULE_LICENSE("GPL"); 761 MODULE_DESCRIPTION("RAID0 (striping) personality for MD"); 762 MODULE_ALIAS("md-personality-2"); /* RAID0 */ 763 MODULE_ALIAS("md-raid0"); 764 MODULE_ALIAS("md-level-0"); 765