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