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 27 static void raid0_unplug(struct request_queue *q) 28 { 29 mddev_t *mddev = q->queuedata; 30 raid0_conf_t *conf = mddev->private; 31 mdk_rdev_t **devlist = conf->devlist; 32 int i; 33 34 for (i=0; i<mddev->raid_disks; i++) { 35 struct request_queue *r_queue = bdev_get_queue(devlist[i]->bdev); 36 37 blk_unplug(r_queue); 38 } 39 } 40 41 static int raid0_congested(void *data, int bits) 42 { 43 mddev_t *mddev = data; 44 raid0_conf_t *conf = mddev->private; 45 mdk_rdev_t **devlist = conf->devlist; 46 int i, ret = 0; 47 48 if (mddev_congested(mddev, bits)) 49 return 1; 50 51 for (i = 0; i < mddev->raid_disks && !ret ; i++) { 52 struct request_queue *q = bdev_get_queue(devlist[i]->bdev); 53 54 ret |= bdi_congested(&q->backing_dev_info, bits); 55 } 56 return ret; 57 } 58 59 /* 60 * inform the user of the raid configuration 61 */ 62 static void dump_zones(mddev_t *mddev) 63 { 64 int j, k, h; 65 sector_t zone_size = 0; 66 sector_t zone_start = 0; 67 char b[BDEVNAME_SIZE]; 68 raid0_conf_t *conf = mddev->private; 69 printk(KERN_INFO "******* %s configuration *********\n", 70 mdname(mddev)); 71 h = 0; 72 for (j = 0; j < conf->nr_strip_zones; j++) { 73 printk(KERN_INFO "zone%d=[", j); 74 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 75 printk("%s/", 76 bdevname(conf->devlist[j*mddev->raid_disks 77 + k]->bdev, b)); 78 printk("]\n"); 79 80 zone_size = conf->strip_zone[j].zone_end - zone_start; 81 printk(KERN_INFO " zone offset=%llukb " 82 "device offset=%llukb size=%llukb\n", 83 (unsigned long long)zone_start>>1, 84 (unsigned long long)conf->strip_zone[j].dev_start>>1, 85 (unsigned long long)zone_size>>1); 86 zone_start = conf->strip_zone[j].zone_end; 87 } 88 printk(KERN_INFO "**********************************\n\n"); 89 } 90 91 static int create_strip_zones(mddev_t *mddev) 92 { 93 int i, c, err; 94 sector_t curr_zone_end, sectors; 95 mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev, **dev; 96 struct strip_zone *zone; 97 int cnt; 98 char b[BDEVNAME_SIZE]; 99 raid0_conf_t *conf = kzalloc(sizeof(*conf), GFP_KERNEL); 100 101 if (!conf) 102 return -ENOMEM; 103 list_for_each_entry(rdev1, &mddev->disks, same_set) { 104 printk(KERN_INFO "raid0: looking at %s\n", 105 bdevname(rdev1->bdev,b)); 106 c = 0; 107 108 /* round size to chunk_size */ 109 sectors = rdev1->sectors; 110 sector_div(sectors, mddev->chunk_sectors); 111 rdev1->sectors = sectors * mddev->chunk_sectors; 112 113 list_for_each_entry(rdev2, &mddev->disks, same_set) { 114 printk(KERN_INFO "raid0: comparing %s(%llu)", 115 bdevname(rdev1->bdev,b), 116 (unsigned long long)rdev1->sectors); 117 printk(KERN_INFO " with %s(%llu)\n", 118 bdevname(rdev2->bdev,b), 119 (unsigned long long)rdev2->sectors); 120 if (rdev2 == rdev1) { 121 printk(KERN_INFO "raid0: END\n"); 122 break; 123 } 124 if (rdev2->sectors == rdev1->sectors) { 125 /* 126 * Not unique, don't count it as a new 127 * group 128 */ 129 printk(KERN_INFO "raid0: EQUAL\n"); 130 c = 1; 131 break; 132 } 133 printk(KERN_INFO "raid0: NOT EQUAL\n"); 134 } 135 if (!c) { 136 printk(KERN_INFO "raid0: ==> UNIQUE\n"); 137 conf->nr_strip_zones++; 138 printk(KERN_INFO "raid0: %d zones\n", 139 conf->nr_strip_zones); 140 } 141 } 142 printk(KERN_INFO "raid0: FINAL %d zones\n", conf->nr_strip_zones); 143 err = -ENOMEM; 144 conf->strip_zone = kzalloc(sizeof(struct strip_zone)* 145 conf->nr_strip_zones, GFP_KERNEL); 146 if (!conf->strip_zone) 147 goto abort; 148 conf->devlist = kzalloc(sizeof(mdk_rdev_t*)* 149 conf->nr_strip_zones*mddev->raid_disks, 150 GFP_KERNEL); 151 if (!conf->devlist) 152 goto abort; 153 154 /* The first zone must contain all devices, so here we check that 155 * there is a proper alignment of slots to devices and find them all 156 */ 157 zone = &conf->strip_zone[0]; 158 cnt = 0; 159 smallest = NULL; 160 dev = conf->devlist; 161 err = -EINVAL; 162 list_for_each_entry(rdev1, &mddev->disks, same_set) { 163 int j = rdev1->raid_disk; 164 165 if (j < 0 || j >= mddev->raid_disks) { 166 printk(KERN_ERR "raid0: bad disk number %d - " 167 "aborting!\n", j); 168 goto abort; 169 } 170 if (dev[j]) { 171 printk(KERN_ERR "raid0: multiple devices for %d - " 172 "aborting!\n", j); 173 goto abort; 174 } 175 dev[j] = rdev1; 176 177 disk_stack_limits(mddev->gendisk, rdev1->bdev, 178 rdev1->data_offset << 9); 179 /* as we don't honour merge_bvec_fn, we must never risk 180 * violating it, so limit ->max_segments to 1, lying within 181 * a single page. 182 */ 183 184 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) { 185 blk_queue_max_segments(mddev->queue, 1); 186 blk_queue_segment_boundary(mddev->queue, 187 PAGE_CACHE_SIZE - 1); 188 } 189 if (!smallest || (rdev1->sectors < smallest->sectors)) 190 smallest = rdev1; 191 cnt++; 192 } 193 if (cnt != mddev->raid_disks) { 194 printk(KERN_ERR "raid0: too few disks (%d of %d) - " 195 "aborting!\n", cnt, mddev->raid_disks); 196 goto abort; 197 } 198 zone->nb_dev = cnt; 199 zone->zone_end = smallest->sectors * cnt; 200 201 curr_zone_end = zone->zone_end; 202 203 /* now do the other zones */ 204 for (i = 1; i < conf->nr_strip_zones; i++) 205 { 206 int j; 207 208 zone = conf->strip_zone + i; 209 dev = conf->devlist + i * mddev->raid_disks; 210 211 printk(KERN_INFO "raid0: zone %d\n", i); 212 zone->dev_start = smallest->sectors; 213 smallest = NULL; 214 c = 0; 215 216 for (j=0; j<cnt; j++) { 217 rdev = conf->devlist[j]; 218 printk(KERN_INFO "raid0: checking %s ...", 219 bdevname(rdev->bdev, b)); 220 if (rdev->sectors <= zone->dev_start) { 221 printk(KERN_INFO " nope.\n"); 222 continue; 223 } 224 printk(KERN_INFO " contained as device %d\n", c); 225 dev[c] = rdev; 226 c++; 227 if (!smallest || rdev->sectors < smallest->sectors) { 228 smallest = rdev; 229 printk(KERN_INFO " (%llu) is smallest!.\n", 230 (unsigned long long)rdev->sectors); 231 } 232 } 233 234 zone->nb_dev = c; 235 sectors = (smallest->sectors - zone->dev_start) * c; 236 printk(KERN_INFO "raid0: zone->nb_dev: %d, sectors: %llu\n", 237 zone->nb_dev, (unsigned long long)sectors); 238 239 curr_zone_end += sectors; 240 zone->zone_end = curr_zone_end; 241 242 printk(KERN_INFO "raid0: current zone start: %llu\n", 243 (unsigned long long)smallest->sectors); 244 } 245 mddev->queue->unplug_fn = raid0_unplug; 246 mddev->queue->backing_dev_info.congested_fn = raid0_congested; 247 mddev->queue->backing_dev_info.congested_data = mddev; 248 249 /* 250 * now since we have the hard sector sizes, we can make sure 251 * chunk size is a multiple of that sector size 252 */ 253 if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) { 254 printk(KERN_ERR "%s chunk_size of %d not valid\n", 255 mdname(mddev), 256 mddev->chunk_sectors << 9); 257 goto abort; 258 } 259 260 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9); 261 blk_queue_io_opt(mddev->queue, 262 (mddev->chunk_sectors << 9) * mddev->raid_disks); 263 264 printk(KERN_INFO "raid0: done.\n"); 265 mddev->private = conf; 266 return 0; 267 abort: 268 kfree(conf->strip_zone); 269 kfree(conf->devlist); 270 kfree(conf); 271 mddev->private = NULL; 272 return err; 273 } 274 275 /** 276 * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged 277 * @q: request queue 278 * @bvm: properties of new bio 279 * @biovec: the request that could be merged to it. 280 * 281 * Return amount of bytes we can accept at this offset 282 */ 283 static int raid0_mergeable_bvec(struct request_queue *q, 284 struct bvec_merge_data *bvm, 285 struct bio_vec *biovec) 286 { 287 mddev_t *mddev = q->queuedata; 288 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); 289 int max; 290 unsigned int chunk_sectors = mddev->chunk_sectors; 291 unsigned int bio_sectors = bvm->bi_size >> 9; 292 293 if (is_power_of_2(chunk_sectors)) 294 max = (chunk_sectors - ((sector & (chunk_sectors-1)) 295 + bio_sectors)) << 9; 296 else 297 max = (chunk_sectors - (sector_div(sector, chunk_sectors) 298 + bio_sectors)) << 9; 299 if (max < 0) max = 0; /* bio_add cannot handle a negative return */ 300 if (max <= biovec->bv_len && bio_sectors == 0) 301 return biovec->bv_len; 302 else 303 return max; 304 } 305 306 static sector_t raid0_size(mddev_t *mddev, sector_t sectors, int raid_disks) 307 { 308 sector_t array_sectors = 0; 309 mdk_rdev_t *rdev; 310 311 WARN_ONCE(sectors || raid_disks, 312 "%s does not support generic reshape\n", __func__); 313 314 list_for_each_entry(rdev, &mddev->disks, same_set) 315 array_sectors += rdev->sectors; 316 317 return array_sectors; 318 } 319 320 static int raid0_run(mddev_t *mddev) 321 { 322 int ret; 323 324 if (mddev->chunk_sectors == 0) { 325 printk(KERN_ERR "md/raid0: chunk size must be set.\n"); 326 return -EINVAL; 327 } 328 if (md_check_no_bitmap(mddev)) 329 return -EINVAL; 330 blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); 331 mddev->queue->queue_lock = &mddev->queue->__queue_lock; 332 333 ret = create_strip_zones(mddev); 334 if (ret < 0) 335 return ret; 336 337 /* calculate array device size */ 338 md_set_array_sectors(mddev, raid0_size(mddev, 0, 0)); 339 340 printk(KERN_INFO "raid0 : md_size is %llu sectors.\n", 341 (unsigned long long)mddev->array_sectors); 342 /* calculate the max read-ahead size. 343 * For read-ahead of large files to be effective, we need to 344 * readahead at least twice a whole stripe. i.e. number of devices 345 * multiplied by chunk size times 2. 346 * If an individual device has an ra_pages greater than the 347 * chunk size, then we will not drive that device as hard as it 348 * wants. We consider this a configuration error: a larger 349 * chunksize should be used in that case. 350 */ 351 { 352 int stripe = mddev->raid_disks * 353 (mddev->chunk_sectors << 9) / PAGE_SIZE; 354 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) 355 mddev->queue->backing_dev_info.ra_pages = 2* stripe; 356 } 357 358 blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec); 359 dump_zones(mddev); 360 md_integrity_register(mddev); 361 return 0; 362 } 363 364 static int raid0_stop(mddev_t *mddev) 365 { 366 raid0_conf_t *conf = mddev->private; 367 368 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 369 kfree(conf->strip_zone); 370 kfree(conf->devlist); 371 kfree(conf); 372 mddev->private = NULL; 373 return 0; 374 } 375 376 /* Find the zone which holds a particular offset 377 * Update *sectorp to be an offset in that zone 378 */ 379 static struct strip_zone *find_zone(struct raid0_private_data *conf, 380 sector_t *sectorp) 381 { 382 int i; 383 struct strip_zone *z = conf->strip_zone; 384 sector_t sector = *sectorp; 385 386 for (i = 0; i < conf->nr_strip_zones; i++) 387 if (sector < z[i].zone_end) { 388 if (i) 389 *sectorp = sector - z[i-1].zone_end; 390 return z + i; 391 } 392 BUG(); 393 } 394 395 /* 396 * remaps the bio to the target device. we separate two flows. 397 * power 2 flow and a general flow for the sake of perfromance 398 */ 399 static mdk_rdev_t *map_sector(mddev_t *mddev, struct strip_zone *zone, 400 sector_t sector, sector_t *sector_offset) 401 { 402 unsigned int sect_in_chunk; 403 sector_t chunk; 404 raid0_conf_t *conf = mddev->private; 405 unsigned int chunk_sects = mddev->chunk_sectors; 406 407 if (is_power_of_2(chunk_sects)) { 408 int chunksect_bits = ffz(~chunk_sects); 409 /* find the sector offset inside the chunk */ 410 sect_in_chunk = sector & (chunk_sects - 1); 411 sector >>= chunksect_bits; 412 /* chunk in zone */ 413 chunk = *sector_offset; 414 /* quotient is the chunk in real device*/ 415 sector_div(chunk, zone->nb_dev << chunksect_bits); 416 } else{ 417 sect_in_chunk = sector_div(sector, chunk_sects); 418 chunk = *sector_offset; 419 sector_div(chunk, chunk_sects * zone->nb_dev); 420 } 421 /* 422 * position the bio over the real device 423 * real sector = chunk in device + starting of zone 424 * + the position in the chunk 425 */ 426 *sector_offset = (chunk * chunk_sects) + sect_in_chunk; 427 return conf->devlist[(zone - conf->strip_zone)*mddev->raid_disks 428 + sector_div(sector, zone->nb_dev)]; 429 } 430 431 /* 432 * Is io distribute over 1 or more chunks ? 433 */ 434 static inline int is_io_in_chunk_boundary(mddev_t *mddev, 435 unsigned int chunk_sects, struct bio *bio) 436 { 437 if (likely(is_power_of_2(chunk_sects))) { 438 return chunk_sects >= ((bio->bi_sector & (chunk_sects-1)) 439 + (bio->bi_size >> 9)); 440 } else{ 441 sector_t sector = bio->bi_sector; 442 return chunk_sects >= (sector_div(sector, chunk_sects) 443 + (bio->bi_size >> 9)); 444 } 445 } 446 447 static int raid0_make_request(struct request_queue *q, struct bio *bio) 448 { 449 mddev_t *mddev = q->queuedata; 450 unsigned int chunk_sects; 451 sector_t sector_offset; 452 struct strip_zone *zone; 453 mdk_rdev_t *tmp_dev; 454 const int rw = bio_data_dir(bio); 455 int cpu; 456 457 if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) { 458 md_barrier_request(mddev, bio); 459 return 0; 460 } 461 462 cpu = part_stat_lock(); 463 part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]); 464 part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], 465 bio_sectors(bio)); 466 part_stat_unlock(); 467 468 chunk_sects = mddev->chunk_sectors; 469 if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) { 470 sector_t sector = bio->bi_sector; 471 struct bio_pair *bp; 472 /* Sanity check -- queue functions should prevent this happening */ 473 if (bio->bi_vcnt != 1 || 474 bio->bi_idx != 0) 475 goto bad_map; 476 /* This is a one page bio that upper layers 477 * refuse to split for us, so we need to split it. 478 */ 479 if (likely(is_power_of_2(chunk_sects))) 480 bp = bio_split(bio, chunk_sects - (sector & 481 (chunk_sects-1))); 482 else 483 bp = bio_split(bio, chunk_sects - 484 sector_div(sector, chunk_sects)); 485 if (raid0_make_request(q, &bp->bio1)) 486 generic_make_request(&bp->bio1); 487 if (raid0_make_request(q, &bp->bio2)) 488 generic_make_request(&bp->bio2); 489 490 bio_pair_release(bp); 491 return 0; 492 } 493 494 sector_offset = bio->bi_sector; 495 zone = find_zone(mddev->private, §or_offset); 496 tmp_dev = map_sector(mddev, zone, bio->bi_sector, 497 §or_offset); 498 bio->bi_bdev = tmp_dev->bdev; 499 bio->bi_sector = sector_offset + zone->dev_start + 500 tmp_dev->data_offset; 501 /* 502 * Let the main block layer submit the IO and resolve recursion: 503 */ 504 return 1; 505 506 bad_map: 507 printk("raid0_make_request bug: can't convert block across chunks" 508 " or bigger than %dk %llu %d\n", chunk_sects / 2, 509 (unsigned long long)bio->bi_sector, bio->bi_size >> 10); 510 511 bio_io_error(bio); 512 return 0; 513 } 514 515 static void raid0_status(struct seq_file *seq, mddev_t *mddev) 516 { 517 #undef MD_DEBUG 518 #ifdef MD_DEBUG 519 int j, k, h; 520 char b[BDEVNAME_SIZE]; 521 raid0_conf_t *conf = mddev->private; 522 523 sector_t zone_size; 524 sector_t zone_start = 0; 525 h = 0; 526 527 for (j = 0; j < conf->nr_strip_zones; j++) { 528 seq_printf(seq, " z%d", j); 529 seq_printf(seq, "=["); 530 for (k = 0; k < conf->strip_zone[j].nb_dev; k++) 531 seq_printf(seq, "%s/", bdevname( 532 conf->devlist[j*mddev->raid_disks + k] 533 ->bdev, b)); 534 535 zone_size = conf->strip_zone[j].zone_end - zone_start; 536 seq_printf(seq, "] ze=%lld ds=%lld s=%lld\n", 537 (unsigned long long)zone_start>>1, 538 (unsigned long long)conf->strip_zone[j].dev_start>>1, 539 (unsigned long long)zone_size>>1); 540 zone_start = conf->strip_zone[j].zone_end; 541 } 542 #endif 543 seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2); 544 return; 545 } 546 547 static struct mdk_personality raid0_personality= 548 { 549 .name = "raid0", 550 .level = 0, 551 .owner = THIS_MODULE, 552 .make_request = raid0_make_request, 553 .run = raid0_run, 554 .stop = raid0_stop, 555 .status = raid0_status, 556 .size = raid0_size, 557 }; 558 559 static int __init raid0_init (void) 560 { 561 return register_md_personality (&raid0_personality); 562 } 563 564 static void raid0_exit (void) 565 { 566 unregister_md_personality (&raid0_personality); 567 } 568 569 module_init(raid0_init); 570 module_exit(raid0_exit); 571 MODULE_LICENSE("GPL"); 572 MODULE_DESCRIPTION("RAID0 (striping) personality for MD"); 573 MODULE_ALIAS("md-personality-2"); /* RAID0 */ 574 MODULE_ALIAS("md-raid0"); 575 MODULE_ALIAS("md-level-0"); 576