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   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                 list_for_each_entry(rdev2, &mddev->disks, same_set) {
 104                         printk(KERN_INFO "raid0:   comparing %s(%llu)",
 105                                bdevname(rdev1->bdev,b),
 106                                (unsigned long long)rdev1->sectors);
 107                         printk(KERN_INFO " with %s(%llu)\n",
 108                                bdevname(rdev2->bdev,b),
 109                                (unsigned long long)rdev2->sectors);
 110                         if (rdev2 == rdev1) {
 111                                 printk(KERN_INFO "raid0:   END\n");
 112                                 break;
 113                         }
 114                         if (rdev2->sectors == rdev1->sectors) {
 115                                 /*
 116                                  * Not unique, don't count it as a new
 117                                  * group
 118                                  */
 119                                 printk(KERN_INFO "raid0:   EQUAL\n");
 120                                 c = 1;
 121                                 break;
 122                         }
 123                         printk(KERN_INFO "raid0:   NOT EQUAL\n");
 124                 }
 125                 if (!c) {
 126                         printk(KERN_INFO "raid0:   ==> UNIQUE\n");
 127                         conf->nr_strip_zones++;
 128                         printk(KERN_INFO "raid0: %d zones\n",
 129                                 conf->nr_strip_zones);
 130                 }
 131         }
 132         printk(KERN_INFO "raid0: FINAL %d zones\n", conf->nr_strip_zones);
 133         err = -ENOMEM;
 134         conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
 135                                 conf->nr_strip_zones, GFP_KERNEL);
 136         if (!conf->strip_zone)
 137                 goto abort;
 138         conf->devlist = kzalloc(sizeof(mdk_rdev_t*)*
 139                                 conf->nr_strip_zones*mddev->raid_disks,
 140                                 GFP_KERNEL);
 141         if (!conf->devlist)
 142                 goto abort;
 143
 144         /* The first zone must contain all devices, so here we check that
 145          * there is a proper alignment of slots to devices and find them all
 146          */
 147         zone = &conf->strip_zone[0];
 148         cnt = 0;
 149         smallest = NULL;
 150         dev = conf->devlist;
 151         err = -EINVAL;
 152         list_for_each_entry(rdev1, &mddev->disks, same_set) {
 153                 int j = rdev1->raid_disk;
 154
 155                 if (j < 0 || j >= mddev->raid_disks) {
 156                         printk(KERN_ERR "raid0: bad disk number %d - "
 157                                 "aborting!\n", j);
 158                         goto abort;
 159                 }
 160                 if (dev[j]) {
 161                         printk(KERN_ERR "raid0: multiple devices for %d - "
 162                                 "aborting!\n", j);
 163                         goto abort;
 164                 }
 165                 dev[j] = rdev1;
 166
 167                 blk_queue_stack_limits(mddev->queue,
 168                                        rdev1->bdev->bd_disk->queue);
 169                 /* as we don't honour merge_bvec_fn, we must never risk
 170                  * violating it, so limit ->max_sector to one PAGE, as
 171                  * a one page request is never in violation.
 172                  */
 173
 174                 if (rdev1->bdev->bd_disk->queue->merge_bvec_fn &&
 175                     queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
 176                         blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
 177
 178                 if (!smallest || (rdev1->sectors < smallest->sectors))
 179                         smallest = rdev1;
 180                 cnt++;
 181         }
 182         if (cnt != mddev->raid_disks) {
 183                 printk(KERN_ERR "raid0: too few disks (%d of %d) - "
 184                         "aborting!\n", cnt, mddev->raid_disks);
 185                 goto abort;
 186         }
 187         zone->nb_dev = cnt;
 188         zone->zone_end = smallest->sectors * cnt;
 189
 190         curr_zone_end = zone->zone_end;
 191
 192         /* now do the other zones */
 193         for (i = 1; i < conf->nr_strip_zones; i++)
 194         {
 195                 zone = conf->strip_zone + i;
 196                 dev = conf->devlist + i * mddev->raid_disks;
 197
 198                 printk(KERN_INFO "raid0: zone %d\n", i);
 199                 zone->dev_start = smallest->sectors;
 200                 smallest = NULL;
 201                 c = 0;
 202
 203                 for (j=0; j<cnt; j++) {
 204                         char b[BDEVNAME_SIZE];
 205                         rdev = conf->devlist[j];
 206                         printk(KERN_INFO "raid0: checking %s ...",
 207                                 bdevname(rdev->bdev, b));
 208                         if (rdev->sectors <= zone->dev_start) {
 209                                 printk(KERN_INFO " nope.\n");
 210                                 continue;
 211                         }
 212                         printk(KERN_INFO " contained as device %d\n", c);
 213                         dev[c] = rdev;
 214                         c++;
 215                         if (!smallest || rdev->sectors < smallest->sectors) {
 216                                 smallest = rdev;
 217                                 printk(KERN_INFO "  (%llu) is smallest!.\n",
 218                                         (unsigned long long)rdev->sectors);
 219                         }
 220                 }
 221
 222                 zone->nb_dev = c;
 223                 sectors = (smallest->sectors - zone->dev_start) * c;
 224                 printk(KERN_INFO "raid0: zone->nb_dev: %d, sectors: %llu\n",
 225                         zone->nb_dev, (unsigned long long)sectors);
 226
 227                 curr_zone_end += sectors;
 228                 zone->zone_end = curr_zone_end;
 229
 230                 printk(KERN_INFO "raid0: current zone start: %llu\n",
 231                         (unsigned long long)smallest->sectors);
 232         }
 233         mddev->queue->unplug_fn = raid0_unplug;
 234         mddev->queue->backing_dev_info.congested_fn = raid0_congested;
 235         mddev->queue->backing_dev_info.congested_data = mddev;
 236
 237         /*
 238          * now since we have the hard sector sizes, we can make sure
 239          * chunk size is a multiple of that sector size
 240          */
 241         if (mddev->chunk_size % queue_logical_block_size(mddev->queue)) {
 242                 printk(KERN_ERR "%s chunk_size of %d not valid\n",
 243                        mdname(mddev),
 244                        mddev->chunk_size);
 245                 goto abort;
 246         }
 247         printk(KERN_INFO "raid0: done.\n");
 248         mddev->private = conf;
 249         return 0;
 250 abort:
 251         kfree(conf->strip_zone);
 252         kfree(conf->devlist);
 253         kfree(conf);
 254         mddev->private = NULL;
 255         return err;
 256 }
 257
 258 /**
 259  *      raid0_mergeable_bvec -- tell bio layer if a two requests can be merged
 260  *      @q: request queue
 261  *      @bvm: properties of new bio
 262  *      @biovec: the request that could be merged to it.
 263  *
 264  *      Return amount of bytes we can accept at this offset
 265  */
 266 static int raid0_mergeable_bvec(struct request_queue *q,
 267                                 struct bvec_merge_data *bvm,
 268                                 struct bio_vec *biovec)
 269 {
 270         mddev_t *mddev = q->queuedata;
 271         sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
 272         int max;
 273         unsigned int chunk_sectors = mddev->chunk_size >> 9;
 274         unsigned int bio_sectors = bvm->bi_size >> 9;
 275
 276         max =  (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
 277         if (max < 0) max = 0; /* bio_add cannot handle a negative return */
 278         if (max <= biovec->bv_len && bio_sectors == 0)
 279                 return biovec->bv_len;
 280         else
 281                 return max;
 282 }
 283
 284 static sector_t raid0_size(mddev_t *mddev, sector_t sectors, int raid_disks)
 285 {
 286         sector_t array_sectors = 0;
 287         mdk_rdev_t *rdev;
 288
 289         WARN_ONCE(sectors || raid_disks,
 290                   "%s does not support generic reshape\n", __func__);
 291
 292         list_for_each_entry(rdev, &mddev->disks, same_set)
 293                 array_sectors += rdev->sectors;
 294
 295         return array_sectors;
 296 }
 297
 298 static int raid0_run(mddev_t *mddev)
 299 {
 300         int ret;
 301
 302         if (mddev->chunk_size == 0 ||
 303             !is_power_of_2(mddev->chunk_size)) {
 304                 printk(KERN_ERR "md/raid0: chunk size must be a power of 2.\n");
 305                 return -EINVAL;
 306         }
 307         blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9);
 308         mddev->queue->queue_lock = &mddev->queue->__queue_lock;
 309
 310         ret = create_strip_zones(mddev);
 311         if (ret < 0)
 312                 return ret;
 313
 314         /* calculate array device size */
 315         md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
 316
 317         printk(KERN_INFO "raid0 : md_size is %llu sectors.\n",
 318                 (unsigned long long)mddev->array_sectors);
 319         /* calculate the max read-ahead size.
 320          * For read-ahead of large files to be effective, we need to
 321          * readahead at least twice a whole stripe. i.e. number of devices
 322          * multiplied by chunk size times 2.
 323          * If an individual device has an ra_pages greater than the
 324          * chunk size, then we will not drive that device as hard as it
 325          * wants.  We consider this a configuration error: a larger
 326          * chunksize should be used in that case.
 327          */
 328         {
 329                 int stripe = mddev->raid_disks * mddev->chunk_size / PAGE_SIZE;
 330                 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
 331                         mddev->queue->backing_dev_info.ra_pages = 2* stripe;
 332         }
 333
 334         blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
 335         dump_zones(mddev);
 336         return 0;
 337 }
 338
 339 static int raid0_stop(mddev_t *mddev)
 340 {
 341         raid0_conf_t *conf = mddev->private;
 342
 343         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
 344         kfree(conf->strip_zone);
 345         kfree(conf->devlist);
 346         kfree(conf);
 347         mddev->private = NULL;
 348         return 0;
 349 }
 350
 351 /* Find the zone which holds a particular offset
 352  * Update *sectorp to be an offset in that zone
 353  */
 354 static struct strip_zone *find_zone(struct raid0_private_data *conf,
 355                                     sector_t *sectorp)
 356 {
 357         int i;
 358         struct strip_zone *z = conf->strip_zone;
 359         sector_t sector = *sectorp;
 360
 361         for (i = 0; i < conf->nr_strip_zones; i++)
 362                 if (sector < z[i].zone_end) {
 363                         if (i)
 364                                 *sectorp = sector - z[i-1].zone_end;
 365                         return z + i;
 366                 }
 367         BUG();
 368 }
 369
 370 static int raid0_make_request (struct request_queue *q, struct bio *bio)
 371 {
 372         mddev_t *mddev = q->queuedata;
 373         unsigned int sect_in_chunk, chunksect_bits, chunk_sects;
 374         raid0_conf_t *conf = mddev->private;
 375         struct strip_zone *zone;
 376         mdk_rdev_t *tmp_dev;
 377         sector_t chunk;
 378         sector_t sector, rsect, sector_offset;
 379         const int rw = bio_data_dir(bio);
 380         int cpu;
 381
 382         if (unlikely(bio_barrier(bio))) {
 383                 bio_endio(bio, -EOPNOTSUPP);
 384                 return 0;
 385         }
 386
 387         cpu = part_stat_lock();
 388         part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
 389         part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
 390                       bio_sectors(bio));
 391         part_stat_unlock();
 392
 393         chunk_sects = mddev->chunk_size >> 9;
 394         chunksect_bits = ffz(~chunk_sects);
 395         sector = bio->bi_sector;
 396
 397         if (unlikely(chunk_sects < (bio->bi_sector & (chunk_sects - 1)) + (bio->bi_size >> 9))) {
 398                 struct bio_pair *bp;
 399                 /* Sanity check -- queue functions should prevent this happening */
 400                 if (bio->bi_vcnt != 1 ||
 401                     bio->bi_idx != 0)
 402                         goto bad_map;
 403                 /* This is a one page bio that upper layers
 404                  * refuse to split for us, so we need to split it.
 405                  */
 406                 bp = bio_split(bio, chunk_sects - (bio->bi_sector & (chunk_sects - 1)));
 407                 if (raid0_make_request(q, &bp->bio1))
 408                         generic_make_request(&bp->bio1);
 409                 if (raid0_make_request(q, &bp->bio2))
 410                         generic_make_request(&bp->bio2);
 411
 412                 bio_pair_release(bp);
 413                 return 0;
 414         }
 415         sector_offset = sector;
 416         zone = find_zone(conf, &sector_offset);
 417         sect_in_chunk = bio->bi_sector & (chunk_sects - 1);
 418         {
 419                 sector_t x = sector_offset >> chunksect_bits;
 420
 421                 sector_div(x, zone->nb_dev);
 422                 chunk = x;
 423
 424                 x = sector >> chunksect_bits;
 425                 tmp_dev = conf->devlist[(zone - conf->strip_zone)*mddev->raid_disks
 426                                         + sector_div(x, zone->nb_dev)];
 427         }
 428         rsect = (chunk << chunksect_bits) + zone->dev_start + sect_in_chunk;
 429
 430         bio->bi_bdev = tmp_dev->bdev;
 431         bio->bi_sector = rsect + tmp_dev->data_offset;
 432
 433         /*
 434          * Let the main block layer submit the IO and resolve recursion:
 435          */
 436         return 1;
 437
 438 bad_map:
 439         printk("raid0_make_request bug: can't convert block across chunks"
 440                 " or bigger than %dk %llu %d\n", chunk_sects / 2,
 441                 (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
 442
 443         bio_io_error(bio);
 444         return 0;
 445 }
 446
 447 static void raid0_status(struct seq_file *seq, mddev_t *mddev)
 448 {
 449 #undef MD_DEBUG
 450 #ifdef MD_DEBUG
 451         int j, k, h;
 452         char b[BDEVNAME_SIZE];
 453         raid0_conf_t *conf = mddev->private;
 454
 455         sector_t zone_size;
 456         sector_t zone_start = 0;
 457         h = 0;
 458
 459         for (j = 0; j < conf->nr_strip_zones; j++) {
 460                 seq_printf(seq, "      z%d", j);
 461                 seq_printf(seq, "=[");
 462                 for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
 463                         seq_printf(seq, "%s/", bdevname(
 464                                 conf->devlist[j*mddev->raid_disks + k]
 465                                                 ->bdev, b));
 466
 467                 zone_size  = conf->strip_zone[j].zone_end - zone_start;
 468                 seq_printf(seq, "] ze=%lld ds=%lld s=%lld\n",
 469                         (unsigned long long)zone_start>>1,
 470                         (unsigned long long)conf->strip_zone[j].dev_start>>1,
 471                         (unsigned long long)zone_size>>1);
 472                 zone_start = conf->strip_zone[j].zone_end;
 473         }
 474 #endif
 475         seq_printf(seq, " %dk chunks", mddev->chunk_size/1024);
 476         return;
 477 }
 478
 479 static struct mdk_personality raid0_personality=
 480 {
 481         .name           = "raid0",
 482         .level          = 0,
 483         .owner          = THIS_MODULE,
 484         .make_request   = raid0_make_request,
 485         .run            = raid0_run,
 486         .stop           = raid0_stop,
 487         .status         = raid0_status,
 488         .size           = raid0_size,
 489 };
 490
 491 static int __init raid0_init (void)
 492 {
 493         return register_md_personality (&raid0_personality);
 494 }
 495
 496 static void raid0_exit (void)
 497 {
 498         unregister_md_personality (&raid0_personality);
 499 }
 500
 501 module_init(raid0_init);
 502 module_exit(raid0_exit);
 503 MODULE_LICENSE("GPL");
 504 MODULE_ALIAS("md-personality-2"); /* RAID0 */
 505 MODULE_ALIAS("md-raid0");
 506 MODULE_ALIAS("md-level-0");