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 "md.h" 24 #include "raid0.h" 25 26 static void raid0_unplug(struct request_queue *q) 27 { 28 mddev_t *mddev = q->queuedata; 29 raid0_conf_t *conf = mddev->private; 30 mdk_rdev_t **devlist = conf->devlist; 31 int i; 32 33 for (i=0; i<mddev->raid_disks; i++) { 34 struct request_queue *r_queue = bdev_get_queue(devlist[i]->bdev); 35 36 blk_unplug(r_queue); 37 } 38 } 39 40 static int raid0_congested(void *data, int bits) 41 { 42 mddev_t *mddev = data; 43 raid0_conf_t *conf = mddev->private; 44 mdk_rdev_t **devlist = conf->devlist; 45 int i, ret = 0; 46 47 if (mddev_congested(mddev, bits)) 48 return 1; 49 50 for (i = 0; i < mddev->raid_disks && !ret ; i++) { 51 struct request_queue *q = bdev_get_queue(devlist[i]->bdev); 52 53 ret |= bdi_congested(&q->backing_dev_info, bits); 54 } 55 return ret; 56 } 57 58 /* 59 * inform the user of the raid configuration 60 */ 61 static void dump_zones(mddev_t *mddev) 62 { 63 int j, k, h; 64 sector_t zone_size = 0; 65 sector_t zone_start = 0; 66 char b[BDEVNAME_SIZE]; 67 raid0_conf_t *conf = mddev->private; 68 printk(KERN_INFO "******* %s configuration *********\n", 69 mdname(mddev)); 70 h = 0; 71 for (j = 0; j < conf->nr_strip_zones; j++) { 72 printk(KERN_INFO "zone%d=[", j); 73 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 74 printk("%s/", 75 bdevname(conf->devlist[j*mddev->raid_disks 76 + k]->bdev, b)); 77 printk("]\n"); 78 79 zone_size = conf->strip_zone[j].zone_end - zone_start; 80 printk(KERN_INFO " zone offset=%llukb " 81 "device offset=%llukb size=%llukb\n", 82 (unsigned long long)zone_start>>1, 83 (unsigned long long)conf->strip_zone[j].dev_start>>1, 84 (unsigned long long)zone_size>>1); 85 zone_start = conf->strip_zone[j].zone_end; 86 } 87 printk(KERN_INFO "**********************************\n\n"); 88 } 89 90 static int create_strip_zones(mddev_t *mddev) 91 { 92 int i, c, err; 93 sector_t curr_zone_end, sectors; 94 mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev, **dev; 95 struct strip_zone *zone; 96 int cnt; 97 char b[BDEVNAME_SIZE]; 98 raid0_conf_t *conf = kzalloc(sizeof(*conf), GFP_KERNEL); 99 100 if (!conf) 101 return -ENOMEM; 102 list_for_each_entry(rdev1, &mddev->disks, same_set) { 103 printk(KERN_INFO "raid0: looking at %s\n", 104 bdevname(rdev1->bdev,b)); 105 c = 0; 106 107 /* round size to chunk_size */ 108 sectors = rdev1->sectors; 109 sector_div(sectors, mddev->chunk_sectors); 110 rdev1->sectors = sectors * mddev->chunk_sectors; 111 112 list_for_each_entry(rdev2, &mddev->disks, same_set) { 113 printk(KERN_INFO "raid0: comparing %s(%llu)", 114 bdevname(rdev1->bdev,b), 115 (unsigned long long)rdev1->sectors); 116 printk(KERN_INFO " with %s(%llu)\n", 117 bdevname(rdev2->bdev,b), 118 (unsigned long long)rdev2->sectors); 119 if (rdev2 == rdev1) { 120 printk(KERN_INFO "raid0: END\n"); 121 break; 122 } 123 if (rdev2->sectors == rdev1->sectors) { 124 /* 125 * Not unique, don't count it as a new 126 * group 127 */ 128 printk(KERN_INFO "raid0: EQUAL\n"); 129 c = 1; 130 break; 131 } 132 printk(KERN_INFO "raid0: NOT EQUAL\n"); 133 } 134 if (!c) { 135 printk(KERN_INFO "raid0: ==> UNIQUE\n"); 136 conf->nr_strip_zones++; 137 printk(KERN_INFO "raid0: %d zones\n", 138 conf->nr_strip_zones); 139 } 140 } 141 printk(KERN_INFO "raid0: FINAL %d zones\n", 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(mdk_rdev_t*)* 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 list_for_each_entry(rdev1, &mddev->disks, same_set) { 162 int j = rdev1->raid_disk; 163 164 if (j < 0 || j >= mddev->raid_disks) { 165 printk(KERN_ERR "raid0: bad disk number %d - " 166 "aborting!\n", j); 167 goto abort; 168 } 169 if (dev[j]) { 170 printk(KERN_ERR "raid0: multiple devices for %d - " 171 "aborting!\n", j); 172 goto abort; 173 } 174 dev[j] = rdev1; 175 176 disk_stack_limits(mddev->gendisk, rdev1->bdev, 177 rdev1->data_offset << 9); 178 /* as we don't honour merge_bvec_fn, we must never risk 179 * violating it, so limit ->max_sector to one PAGE, as 180 * a one page request is never in violation. 181 */ 182 183 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn && 184 queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9)) 185 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); 186 187 if (!smallest || (rdev1->sectors < smallest->sectors)) 188 smallest = rdev1; 189 cnt++; 190 } 191 if (cnt != mddev->raid_disks) { 192 printk(KERN_ERR "raid0: too few disks (%d of %d) - " 193 "aborting!\n", cnt, mddev->raid_disks); 194 goto abort; 195 } 196 zone->nb_dev = cnt; 197 zone->zone_end = smallest->sectors * cnt; 198 199 curr_zone_end = zone->zone_end; 200 201 /* now do the other zones */ 202 for (i = 1; i < conf->nr_strip_zones; i++) 203 { 204 int j; 205 206 zone = conf->strip_zone + i; 207 dev = conf->devlist + i * mddev->raid_disks; 208 209 printk(KERN_INFO "raid0: zone %d\n", i); 210 zone->dev_start = smallest->sectors; 211 smallest = NULL; 212 c = 0; 213 214 for (j=0; j<cnt; j++) { 215 rdev = conf->devlist[j]; 216 printk(KERN_INFO "raid0: checking %s ...", 217 bdevname(rdev->bdev, b)); 218 if (rdev->sectors <= zone->dev_start) { 219 printk(KERN_INFO " nope.\n"); 220 continue; 221 } 222 printk(KERN_INFO " contained as device %d\n", c); 223 dev[c] = rdev; 224 c++; 225 if (!smallest || rdev->sectors < smallest->sectors) { 226 smallest = rdev; 227 printk(KERN_INFO " (%llu) is smallest!.\n", 228 (unsigned long long)rdev->sectors); 229 } 230 } 231 232 zone->nb_dev = c; 233 sectors = (smallest->sectors - zone->dev_start) * c; 234 printk(KERN_INFO "raid0: zone->nb_dev: %d, sectors: %llu\n", 235 zone->nb_dev, (unsigned long long)sectors); 236 237 curr_zone_end += sectors; 238 zone->zone_end = curr_zone_end; 239 240 printk(KERN_INFO "raid0: current zone start: %llu\n", 241 (unsigned long long)smallest->sectors); 242 } 243 mddev->queue->unplug_fn = raid0_unplug; 244 mddev->queue->backing_dev_info.congested_fn = raid0_congested; 245 mddev->queue->backing_dev_info.congested_data = mddev; 246 247 /* 248 * now since we have the hard sector sizes, we can make sure 249 * chunk size is a multiple of that sector size 250 */ 251 if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) { 252 printk(KERN_ERR "%s chunk_size of %d not valid\n", 253 mdname(mddev), 254 mddev->chunk_sectors << 9); 255 goto abort; 256 } 257 258 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9); 259 blk_queue_io_opt(mddev->queue, 260 (mddev->chunk_sectors << 9) * mddev->raid_disks); 261 262 printk(KERN_INFO "raid0: done.\n"); 263 mddev->private = conf; 264 return 0; 265 abort: 266 kfree(conf->strip_zone); 267 kfree(conf->devlist); 268 kfree(conf); 269 mddev->private = NULL; 270 return err; 271 } 272 273 /** 274 * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged 275 * @q: request queue 276 * @bvm: properties of new bio 277 * @biovec: the request that could be merged to it. 278 * 279 * Return amount of bytes we can accept at this offset 280 */ 281 static int raid0_mergeable_bvec(struct request_queue *q, 282 struct bvec_merge_data *bvm, 283 struct bio_vec *biovec) 284 { 285 mddev_t *mddev = q->queuedata; 286 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); 287 int max; 288 unsigned int chunk_sectors = mddev->chunk_sectors; 289 unsigned int bio_sectors = bvm->bi_size >> 9; 290 291 if (is_power_of_2(chunk_sectors)) 292 max = (chunk_sectors - ((sector & (chunk_sectors-1)) 293 + bio_sectors)) << 9; 294 else 295 max = (chunk_sectors - (sector_div(sector, chunk_sectors) 296 + bio_sectors)) << 9; 297 if (max < 0) max = 0; /* bio_add cannot handle a negative return */ 298 if (max <= biovec->bv_len && bio_sectors == 0) 299 return biovec->bv_len; 300 else 301 return max; 302 } 303 304 static sector_t raid0_size(mddev_t *mddev, sector_t sectors, int raid_disks) 305 { 306 sector_t array_sectors = 0; 307 mdk_rdev_t *rdev; 308 309 WARN_ONCE(sectors || raid_disks, 310 "%s does not support generic reshape\n", __func__); 311 312 list_for_each_entry(rdev, &mddev->disks, same_set) 313 array_sectors += rdev->sectors; 314 315 return array_sectors; 316 } 317 318 static int raid0_run(mddev_t *mddev) 319 { 320 int ret; 321 322 if (mddev->chunk_sectors == 0) { 323 printk(KERN_ERR "md/raid0: chunk size must be set.\n"); 324 return -EINVAL; 325 } 326 if (md_check_no_bitmap(mddev)) 327 return -EINVAL; 328 blk_queue_max_sectors(mddev->queue, mddev->chunk_sectors); 329 mddev->queue->queue_lock = &mddev->queue->__queue_lock; 330 331 ret = create_strip_zones(mddev); 332 if (ret < 0) 333 return ret; 334 335 /* calculate array device size */ 336 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); 337 338 printk(KERN_INFO "raid0 : md_size is %llu sectors.\n", 339 (unsigned long long)mddev->array_sectors); 340 /* calculate the max read-ahead size. 341 * For read-ahead of large files to be effective, we need to 342 * readahead at least twice a whole stripe. i.e. number of devices 343 * multiplied by chunk size times 2. 344 * If an individual device has an ra_pages greater than the 345 * chunk size, then we will not drive that device as hard as it 346 * wants. We consider this a configuration error: a larger 347 * chunksize should be used in that case. 348 */ 349 { 350 int stripe = mddev->raid_disks * 351 (mddev->chunk_sectors << 9) / PAGE_SIZE; 352 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) 353 mddev->queue->backing_dev_info.ra_pages = 2* stripe; 354 } 355 356 blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec); 357 dump_zones(mddev); 358 md_integrity_register(mddev); 359 return 0; 360 } 361 362 static int raid0_stop(mddev_t *mddev) 363 { 364 raid0_conf_t *conf = mddev->private; 365 366 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 367 kfree(conf->strip_zone); 368 kfree(conf->devlist); 369 kfree(conf); 370 mddev->private = NULL; 371 return 0; 372 } 373 374 /* Find the zone which holds a particular offset 375 * Update *sectorp to be an offset in that zone 376 */ 377 static struct strip_zone *find_zone(struct raid0_private_data *conf, 378 sector_t *sectorp) 379 { 380 int i; 381 struct strip_zone *z = conf->strip_zone; 382 sector_t sector = *sectorp; 383 384 for (i = 0; i < conf->nr_strip_zones; i++) 385 if (sector < z[i].zone_end) { 386 if (i) 387 *sectorp = sector - z[i-1].zone_end; 388 return z + i; 389 } 390 BUG(); 391 } 392 393 /* 394 * remaps the bio to the target device. we separate two flows. 395 * power 2 flow and a general flow for the sake of perfromance 396 */ 397 static mdk_rdev_t *map_sector(mddev_t *mddev, struct strip_zone *zone, 398 sector_t sector, sector_t *sector_offset) 399 { 400 unsigned int sect_in_chunk; 401 sector_t chunk; 402 raid0_conf_t *conf = mddev->private; 403 unsigned int chunk_sects = mddev->chunk_sectors; 404 405 if (is_power_of_2(chunk_sects)) { 406 int chunksect_bits = ffz(~chunk_sects); 407 /* find the sector offset inside the chunk */ 408 sect_in_chunk = sector & (chunk_sects - 1); 409 sector >>= chunksect_bits; 410 /* chunk in zone */ 411 chunk = *sector_offset; 412 /* quotient is the chunk in real device*/ 413 sector_div(chunk, zone->nb_dev << chunksect_bits); 414 } else{ 415 sect_in_chunk = sector_div(sector, chunk_sects); 416 chunk = *sector_offset; 417 sector_div(chunk, chunk_sects * zone->nb_dev); 418 } 419 /* 420 * position the bio over the real device 421 * real sector = chunk in device + starting of zone 422 * + the position in the chunk 423 */ 424 *sector_offset = (chunk * chunk_sects) + sect_in_chunk; 425 return conf->devlist[(zone - conf->strip_zone)*mddev->raid_disks 426 + sector_div(sector, zone->nb_dev)]; 427 } 428 429 /* 430 * Is io distribute over 1 or more chunks ? 431 */ 432 static inline int is_io_in_chunk_boundary(mddev_t *mddev, 433 unsigned int chunk_sects, struct bio *bio) 434 { 435 if (likely(is_power_of_2(chunk_sects))) { 436 return chunk_sects >= ((bio->bi_sector & (chunk_sects-1)) 437 + (bio->bi_size >> 9)); 438 } else{ 439 sector_t sector = bio->bi_sector; 440 return chunk_sects >= (sector_div(sector, chunk_sects) 441 + (bio->bi_size >> 9)); 442 } 443 } 444 445 static int raid0_make_request(struct request_queue *q, struct bio *bio) 446 { 447 mddev_t *mddev = q->queuedata; 448 unsigned int chunk_sects; 449 sector_t sector_offset; 450 struct strip_zone *zone; 451 mdk_rdev_t *tmp_dev; 452 const int rw = bio_data_dir(bio); 453 int cpu; 454 455 if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) { 456 md_barrier_request(mddev, bio); 457 return 0; 458 } 459 460 cpu = part_stat_lock(); 461 part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]); 462 part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], 463 bio_sectors(bio)); 464 part_stat_unlock(); 465 466 chunk_sects = mddev->chunk_sectors; 467 if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) { 468 sector_t sector = bio->bi_sector; 469 struct bio_pair *bp; 470 /* Sanity check -- queue functions should prevent this happening */ 471 if (bio->bi_vcnt != 1 || 472 bio->bi_idx != 0) 473 goto bad_map; 474 /* This is a one page bio that upper layers 475 * refuse to split for us, so we need to split it. 476 */ 477 if (likely(is_power_of_2(chunk_sects))) 478 bp = bio_split(bio, chunk_sects - (sector & 479 (chunk_sects-1))); 480 else 481 bp = bio_split(bio, chunk_sects - 482 sector_div(sector, chunk_sects)); 483 if (raid0_make_request(q, &bp->bio1)) 484 generic_make_request(&bp->bio1); 485 if (raid0_make_request(q, &bp->bio2)) 486 generic_make_request(&bp->bio2); 487 488 bio_pair_release(bp); 489 return 0; 490 } 491 492 sector_offset = bio->bi_sector; 493 zone = find_zone(mddev->private, §or_offset); 494 tmp_dev = map_sector(mddev, zone, bio->bi_sector, 495 §or_offset); 496 bio->bi_bdev = tmp_dev->bdev; 497 bio->bi_sector = sector_offset + zone->dev_start + 498 tmp_dev->data_offset; 499 /* 500 * Let the main block layer submit the IO and resolve recursion: 501 */ 502 return 1; 503 504 bad_map: 505 printk("raid0_make_request bug: can't convert block across chunks" 506 " or bigger than %dk %llu %d\n", chunk_sects / 2, 507 (unsigned long long)bio->bi_sector, bio->bi_size >> 10); 508 509 bio_io_error(bio); 510 return 0; 511 } 512 513 static void raid0_status(struct seq_file *seq, mddev_t *mddev) 514 { 515 #undef MD_DEBUG 516 #ifdef MD_DEBUG 517 int j, k, h; 518 char b[BDEVNAME_SIZE]; 519 raid0_conf_t *conf = mddev->private; 520 521 sector_t zone_size; 522 sector_t zone_start = 0; 523 h = 0; 524 525 for (j = 0; j < conf->nr_strip_zones; j++) { 526 seq_printf(seq, " z%d", j); 527 seq_printf(seq, "=["); 528 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 529 seq_printf(seq, "%s/", bdevname( 530 conf->devlist[j*mddev->raid_disks + k] 531 ->bdev, b)); 532 533 zone_size = conf->strip_zone[j].zone_end - zone_start; 534 seq_printf(seq, "] ze=%lld ds=%lld s=%lld\n", 535 (unsigned long long)zone_start>>1, 536 (unsigned long long)conf->strip_zone[j].dev_start>>1, 537 (unsigned long long)zone_size>>1); 538 zone_start = conf->strip_zone[j].zone_end; 539 } 540 #endif 541 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2); 542 return; 543 } 544 545 static struct mdk_personality raid0_personality= 546 { 547 .name = "raid0", 548 .level = 0, 549 .owner = THIS_MODULE, 550 .make_request = raid0_make_request, 551 .run = raid0_run, 552 .stop = raid0_stop, 553 .status = raid0_status, 554 .size = raid0_size, 555 }; 556 557 static int __init raid0_init (void) 558 { 559 return register_md_personality (&raid0_personality); 560 } 561 562 static void raid0_exit (void) 563 { 564 unregister_md_personality (&raid0_personality); 565 } 566 567 module_init(raid0_init); 568 module_exit(raid0_exit); 569 MODULE_LICENSE("GPL"); 570 MODULE_DESCRIPTION("RAID0 (striping) personality for MD"); 571 MODULE_ALIAS("md-personality-2"); /* RAID0 */ 572 MODULE_ALIAS("md-raid0"); 573 MODULE_ALIAS("md-level-0"); 574