1 /* 2 * Copyright (C) 2010-2011 Neil Brown 3 * Copyright (C) 2010-2011 Red Hat, Inc. All rights reserved. 4 * 5 * This file is released under the GPL. 6 */ 7 8 #include <linux/slab.h> 9 10 #include "md.h" 11 #include "raid5.h" 12 #include "dm.h" 13 #include "bitmap.h" 14 15 #define DM_MSG_PREFIX "raid" 16 17 /* 18 * If the MD doesn't support MD_SYNC_STATE_FORCED yet, then 19 * make it so the flag doesn't set anything. 20 */ 21 #ifndef MD_SYNC_STATE_FORCED 22 #define MD_SYNC_STATE_FORCED 0 23 #endif 24 25 struct raid_dev { 26 /* 27 * Two DM devices, one to hold metadata and one to hold the 28 * actual data/parity. The reason for this is to not confuse 29 * ti->len and give more flexibility in altering size and 30 * characteristics. 31 * 32 * While it is possible for this device to be associated 33 * with a different physical device than the data_dev, it 34 * is intended for it to be the same. 35 * |--------- Physical Device ---------| 36 * |- meta_dev -|------ data_dev ------| 37 */ 38 struct dm_dev *meta_dev; 39 struct dm_dev *data_dev; 40 struct mdk_rdev_s rdev; 41 }; 42 43 /* 44 * Flags for rs->print_flags field. 45 */ 46 #define DMPF_DAEMON_SLEEP 0x1 47 #define DMPF_MAX_WRITE_BEHIND 0x2 48 #define DMPF_SYNC 0x4 49 #define DMPF_NOSYNC 0x8 50 #define DMPF_STRIPE_CACHE 0x10 51 #define DMPF_MIN_RECOVERY_RATE 0x20 52 #define DMPF_MAX_RECOVERY_RATE 0x40 53 54 struct raid_set { 55 struct dm_target *ti; 56 57 uint64_t print_flags; 58 59 struct mddev_s md; 60 struct raid_type *raid_type; 61 struct dm_target_callbacks callbacks; 62 63 struct raid_dev dev[0]; 64 }; 65 66 /* Supported raid types and properties. */ 67 static struct raid_type { 68 const char *name; /* RAID algorithm. */ 69 const char *descr; /* Descriptor text for logging. */ 70 const unsigned parity_devs; /* # of parity devices. */ 71 const unsigned minimal_devs; /* minimal # of devices in set. */ 72 const unsigned level; /* RAID level. */ 73 const unsigned algorithm; /* RAID algorithm. */ 74 } raid_types[] = { 75 {"raid4", "RAID4 (dedicated parity disk)", 1, 2, 5, ALGORITHM_PARITY_0}, 76 {"raid5_la", "RAID5 (left asymmetric)", 1, 2, 5, ALGORITHM_LEFT_ASYMMETRIC}, 77 {"raid5_ra", "RAID5 (right asymmetric)", 1, 2, 5, ALGORITHM_RIGHT_ASYMMETRIC}, 78 {"raid5_ls", "RAID5 (left symmetric)", 1, 2, 5, ALGORITHM_LEFT_SYMMETRIC}, 79 {"raid5_rs", "RAID5 (right symmetric)", 1, 2, 5, ALGORITHM_RIGHT_SYMMETRIC}, 80 {"raid6_zr", "RAID6 (zero restart)", 2, 4, 6, ALGORITHM_ROTATING_ZERO_RESTART}, 81 {"raid6_nr", "RAID6 (N restart)", 2, 4, 6, ALGORITHM_ROTATING_N_RESTART}, 82 {"raid6_nc", "RAID6 (N continue)", 2, 4, 6, ALGORITHM_ROTATING_N_CONTINUE} 83 }; 84 85 static struct raid_type *get_raid_type(char *name) 86 { 87 int i; 88 89 for (i = 0; i < ARRAY_SIZE(raid_types); i++) 90 if (!strcmp(raid_types[i].name, name)) 91 return &raid_types[i]; 92 93 return NULL; 94 } 95 96 static struct raid_set *context_alloc(struct dm_target *ti, struct raid_type *raid_type, unsigned raid_devs) 97 { 98 unsigned i; 99 struct raid_set *rs; 100 sector_t sectors_per_dev; 101 102 if (raid_devs <= raid_type->parity_devs) { 103 ti->error = "Insufficient number of devices"; 104 return ERR_PTR(-EINVAL); 105 } 106 107 sectors_per_dev = ti->len; 108 if (sector_div(sectors_per_dev, (raid_devs - raid_type->parity_devs))) { 109 ti->error = "Target length not divisible by number of data devices"; 110 return ERR_PTR(-EINVAL); 111 } 112 113 rs = kzalloc(sizeof(*rs) + raid_devs * sizeof(rs->dev[0]), GFP_KERNEL); 114 if (!rs) { 115 ti->error = "Cannot allocate raid context"; 116 return ERR_PTR(-ENOMEM); 117 } 118 119 mddev_init(&rs->md); 120 121 rs->ti = ti; 122 rs->raid_type = raid_type; 123 rs->md.raid_disks = raid_devs; 124 rs->md.level = raid_type->level; 125 rs->md.new_level = rs->md.level; 126 rs->md.dev_sectors = sectors_per_dev; 127 rs->md.layout = raid_type->algorithm; 128 rs->md.new_layout = rs->md.layout; 129 rs->md.delta_disks = 0; 130 rs->md.recovery_cp = 0; 131 132 for (i = 0; i < raid_devs; i++) 133 md_rdev_init(&rs->dev[i].rdev); 134 135 /* 136 * Remaining items to be initialized by further RAID params: 137 * rs->md.persistent 138 * rs->md.external 139 * rs->md.chunk_sectors 140 * rs->md.new_chunk_sectors 141 */ 142 143 return rs; 144 } 145 146 static void context_free(struct raid_set *rs) 147 { 148 int i; 149 150 for (i = 0; i < rs->md.raid_disks; i++) 151 if (rs->dev[i].data_dev) 152 dm_put_device(rs->ti, rs->dev[i].data_dev); 153 154 kfree(rs); 155 } 156 157 /* 158 * For every device we have two words 159 * <meta_dev>: meta device name or '-' if missing 160 * <data_dev>: data device name or '-' if missing 161 * 162 * This code parses those words. 163 */ 164 static int dev_parms(struct raid_set *rs, char **argv) 165 { 166 int i; 167 int rebuild = 0; 168 int metadata_available = 0; 169 int ret = 0; 170 171 for (i = 0; i < rs->md.raid_disks; i++, argv += 2) { 172 rs->dev[i].rdev.raid_disk = i; 173 174 rs->dev[i].meta_dev = NULL; 175 rs->dev[i].data_dev = NULL; 176 177 /* 178 * There are no offsets, since there is a separate device 179 * for data and metadata. 180 */ 181 rs->dev[i].rdev.data_offset = 0; 182 rs->dev[i].rdev.mddev = &rs->md; 183 184 if (strcmp(argv[0], "-")) { 185 rs->ti->error = "Metadata devices not supported"; 186 return -EINVAL; 187 } 188 189 if (!strcmp(argv[1], "-")) { 190 if (!test_bit(In_sync, &rs->dev[i].rdev.flags) && 191 (!rs->dev[i].rdev.recovery_offset)) { 192 rs->ti->error = "Drive designated for rebuild not specified"; 193 return -EINVAL; 194 } 195 196 continue; 197 } 198 199 ret = dm_get_device(rs->ti, argv[1], 200 dm_table_get_mode(rs->ti->table), 201 &rs->dev[i].data_dev); 202 if (ret) { 203 rs->ti->error = "RAID device lookup failure"; 204 return ret; 205 } 206 207 rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev; 208 list_add(&rs->dev[i].rdev.same_set, &rs->md.disks); 209 if (!test_bit(In_sync, &rs->dev[i].rdev.flags)) 210 rebuild++; 211 } 212 213 if (metadata_available) { 214 rs->md.external = 0; 215 rs->md.persistent = 1; 216 rs->md.major_version = 2; 217 } else if (rebuild && !rs->md.recovery_cp) { 218 /* 219 * Without metadata, we will not be able to tell if the array 220 * is in-sync or not - we must assume it is not. Therefore, 221 * it is impossible to rebuild a drive. 222 * 223 * Even if there is metadata, the on-disk information may 224 * indicate that the array is not in-sync and it will then 225 * fail at that time. 226 * 227 * User could specify 'nosync' option if desperate. 228 */ 229 DMERR("Unable to rebuild drive while array is not in-sync"); 230 rs->ti->error = "RAID device lookup failure"; 231 return -EINVAL; 232 } 233 234 return 0; 235 } 236 237 /* 238 * Possible arguments are... 239 * RAID456: 240 * <chunk_size> [optional_args] 241 * 242 * Optional args: 243 * [[no]sync] Force or prevent recovery of the entire array 244 * [rebuild <idx>] Rebuild the drive indicated by the index 245 * [daemon_sleep <ms>] Time between bitmap daemon work to clear bits 246 * [min_recovery_rate <kB/sec/disk>] Throttle RAID initialization 247 * [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization 248 * [max_write_behind <sectors>] See '-write-behind=' (man mdadm) 249 * [stripe_cache <sectors>] Stripe cache size for higher RAIDs 250 */ 251 static int parse_raid_params(struct raid_set *rs, char **argv, 252 unsigned num_raid_params) 253 { 254 unsigned i, rebuild_cnt = 0; 255 unsigned long value; 256 char *key; 257 258 /* 259 * First, parse the in-order required arguments 260 */ 261 if ((strict_strtoul(argv[0], 10, &value) < 0) || 262 !is_power_of_2(value) || (value < 8)) { 263 rs->ti->error = "Bad chunk size"; 264 return -EINVAL; 265 } 266 267 rs->md.new_chunk_sectors = rs->md.chunk_sectors = value; 268 argv++; 269 num_raid_params--; 270 271 /* 272 * Second, parse the unordered optional arguments 273 */ 274 for (i = 0; i < rs->md.raid_disks; i++) 275 set_bit(In_sync, &rs->dev[i].rdev.flags); 276 277 for (i = 0; i < num_raid_params; i++) { 278 if (!strcmp(argv[i], "nosync")) { 279 rs->md.recovery_cp = MaxSector; 280 rs->print_flags |= DMPF_NOSYNC; 281 rs->md.flags |= MD_SYNC_STATE_FORCED; 282 continue; 283 } 284 if (!strcmp(argv[i], "sync")) { 285 rs->md.recovery_cp = 0; 286 rs->print_flags |= DMPF_SYNC; 287 rs->md.flags |= MD_SYNC_STATE_FORCED; 288 continue; 289 } 290 291 /* The rest of the optional arguments come in key/value pairs */ 292 if ((i + 1) >= num_raid_params) { 293 rs->ti->error = "Wrong number of raid parameters given"; 294 return -EINVAL; 295 } 296 297 key = argv[i++]; 298 if (strict_strtoul(argv[i], 10, &value) < 0) { 299 rs->ti->error = "Bad numerical argument given in raid params"; 300 return -EINVAL; 301 } 302 303 if (!strcmp(key, "rebuild")) { 304 if (++rebuild_cnt > rs->raid_type->parity_devs) { 305 rs->ti->error = "Too many rebuild drives given"; 306 return -EINVAL; 307 } 308 if (value > rs->md.raid_disks) { 309 rs->ti->error = "Invalid rebuild index given"; 310 return -EINVAL; 311 } 312 clear_bit(In_sync, &rs->dev[value].rdev.flags); 313 rs->dev[value].rdev.recovery_offset = 0; 314 } else if (!strcmp(key, "max_write_behind")) { 315 rs->print_flags |= DMPF_MAX_WRITE_BEHIND; 316 317 /* 318 * In device-mapper, we specify things in sectors, but 319 * MD records this value in kB 320 */ 321 value /= 2; 322 if (value > COUNTER_MAX) { 323 rs->ti->error = "Max write-behind limit out of range"; 324 return -EINVAL; 325 } 326 rs->md.bitmap_info.max_write_behind = value; 327 } else if (!strcmp(key, "daemon_sleep")) { 328 rs->print_flags |= DMPF_DAEMON_SLEEP; 329 if (!value || (value > MAX_SCHEDULE_TIMEOUT)) { 330 rs->ti->error = "daemon sleep period out of range"; 331 return -EINVAL; 332 } 333 rs->md.bitmap_info.daemon_sleep = value; 334 } else if (!strcmp(key, "stripe_cache")) { 335 rs->print_flags |= DMPF_STRIPE_CACHE; 336 337 /* 338 * In device-mapper, we specify things in sectors, but 339 * MD records this value in kB 340 */ 341 value /= 2; 342 343 if (rs->raid_type->level < 5) { 344 rs->ti->error = "Inappropriate argument: stripe_cache"; 345 return -EINVAL; 346 } 347 if (raid5_set_cache_size(&rs->md, (int)value)) { 348 rs->ti->error = "Bad stripe_cache size"; 349 return -EINVAL; 350 } 351 } else if (!strcmp(key, "min_recovery_rate")) { 352 rs->print_flags |= DMPF_MIN_RECOVERY_RATE; 353 if (value > INT_MAX) { 354 rs->ti->error = "min_recovery_rate out of range"; 355 return -EINVAL; 356 } 357 rs->md.sync_speed_min = (int)value; 358 } else if (!strcmp(key, "max_recovery_rate")) { 359 rs->print_flags |= DMPF_MAX_RECOVERY_RATE; 360 if (value > INT_MAX) { 361 rs->ti->error = "max_recovery_rate out of range"; 362 return -EINVAL; 363 } 364 rs->md.sync_speed_max = (int)value; 365 } else { 366 DMERR("Unable to parse RAID parameter: %s", key); 367 rs->ti->error = "Unable to parse RAID parameters"; 368 return -EINVAL; 369 } 370 } 371 372 /* Assume there are no metadata devices until the drives are parsed */ 373 rs->md.persistent = 0; 374 rs->md.external = 1; 375 376 return 0; 377 } 378 379 static void do_table_event(struct work_struct *ws) 380 { 381 struct raid_set *rs = container_of(ws, struct raid_set, md.event_work); 382 383 dm_table_event(rs->ti->table); 384 } 385 386 static int raid_is_congested(struct dm_target_callbacks *cb, int bits) 387 { 388 struct raid_set *rs = container_of(cb, struct raid_set, callbacks); 389 390 return md_raid5_congested(&rs->md, bits); 391 } 392 393 static void raid_unplug(struct dm_target_callbacks *cb) 394 { 395 struct raid_set *rs = container_of(cb, struct raid_set, callbacks); 396 397 md_raid5_unplug_device(rs->md.private); 398 } 399 400 /* 401 * Construct a RAID4/5/6 mapping: 402 * Args: 403 * <raid_type> <#raid_params> <raid_params> \ 404 * <#raid_devs> { <meta_dev1> <dev1> .. <meta_devN> <devN> } 405 * 406 * ** metadata devices are not supported yet, use '-' instead ** 407 * 408 * <raid_params> varies by <raid_type>. See 'parse_raid_params' for 409 * details on possible <raid_params>. 410 */ 411 static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv) 412 { 413 int ret; 414 struct raid_type *rt; 415 unsigned long num_raid_params, num_raid_devs; 416 struct raid_set *rs = NULL; 417 418 /* Must have at least <raid_type> <#raid_params> */ 419 if (argc < 2) { 420 ti->error = "Too few arguments"; 421 return -EINVAL; 422 } 423 424 /* raid type */ 425 rt = get_raid_type(argv[0]); 426 if (!rt) { 427 ti->error = "Unrecognised raid_type"; 428 return -EINVAL; 429 } 430 argc--; 431 argv++; 432 433 /* number of RAID parameters */ 434 if (strict_strtoul(argv[0], 10, &num_raid_params) < 0) { 435 ti->error = "Cannot understand number of RAID parameters"; 436 return -EINVAL; 437 } 438 argc--; 439 argv++; 440 441 /* Skip over RAID params for now and find out # of devices */ 442 if (num_raid_params + 1 > argc) { 443 ti->error = "Arguments do not agree with counts given"; 444 return -EINVAL; 445 } 446 447 if ((strict_strtoul(argv[num_raid_params], 10, &num_raid_devs) < 0) || 448 (num_raid_devs >= INT_MAX)) { 449 ti->error = "Cannot understand number of raid devices"; 450 return -EINVAL; 451 } 452 453 rs = context_alloc(ti, rt, (unsigned)num_raid_devs); 454 if (IS_ERR(rs)) 455 return PTR_ERR(rs); 456 457 ret = parse_raid_params(rs, argv, (unsigned)num_raid_params); 458 if (ret) 459 goto bad; 460 461 ret = -EINVAL; 462 463 argc -= num_raid_params + 1; /* +1: we already have num_raid_devs */ 464 argv += num_raid_params + 1; 465 466 if (argc != (num_raid_devs * 2)) { 467 ti->error = "Supplied RAID devices does not match the count given"; 468 goto bad; 469 } 470 471 ret = dev_parms(rs, argv); 472 if (ret) 473 goto bad; 474 475 INIT_WORK(&rs->md.event_work, do_table_event); 476 ti->split_io = rs->md.chunk_sectors; 477 ti->private = rs; 478 479 mutex_lock(&rs->md.reconfig_mutex); 480 ret = md_run(&rs->md); 481 rs->md.in_sync = 0; /* Assume already marked dirty */ 482 mutex_unlock(&rs->md.reconfig_mutex); 483 484 if (ret) { 485 ti->error = "Fail to run raid array"; 486 goto bad; 487 } 488 489 rs->callbacks.congested_fn = raid_is_congested; 490 rs->callbacks.unplug_fn = raid_unplug; 491 dm_table_add_target_callbacks(ti->table, &rs->callbacks); 492 493 return 0; 494 495 bad: 496 context_free(rs); 497 498 return ret; 499 } 500 501 static void raid_dtr(struct dm_target *ti) 502 { 503 struct raid_set *rs = ti->private; 504 505 list_del_init(&rs->callbacks.list); 506 md_stop(&rs->md); 507 context_free(rs); 508 } 509 510 static int raid_map(struct dm_target *ti, struct bio *bio, union map_info *map_context) 511 { 512 struct raid_set *rs = ti->private; 513 mddev_t *mddev = &rs->md; 514 515 mddev->pers->make_request(mddev, bio); 516 517 return DM_MAPIO_SUBMITTED; 518 } 519 520 static int raid_status(struct dm_target *ti, status_type_t type, 521 char *result, unsigned maxlen) 522 { 523 struct raid_set *rs = ti->private; 524 unsigned raid_param_cnt = 1; /* at least 1 for chunksize */ 525 unsigned sz = 0; 526 int i; 527 sector_t sync; 528 529 switch (type) { 530 case STATUSTYPE_INFO: 531 DMEMIT("%s %d ", rs->raid_type->name, rs->md.raid_disks); 532 533 for (i = 0; i < rs->md.raid_disks; i++) { 534 if (test_bit(Faulty, &rs->dev[i].rdev.flags)) 535 DMEMIT("D"); 536 else if (test_bit(In_sync, &rs->dev[i].rdev.flags)) 537 DMEMIT("A"); 538 else 539 DMEMIT("a"); 540 } 541 542 if (test_bit(MD_RECOVERY_RUNNING, &rs->md.recovery)) 543 sync = rs->md.curr_resync_completed; 544 else 545 sync = rs->md.recovery_cp; 546 547 if (sync > rs->md.resync_max_sectors) 548 sync = rs->md.resync_max_sectors; 549 550 DMEMIT(" %llu/%llu", 551 (unsigned long long) sync, 552 (unsigned long long) rs->md.resync_max_sectors); 553 554 break; 555 case STATUSTYPE_TABLE: 556 /* The string you would use to construct this array */ 557 for (i = 0; i < rs->md.raid_disks; i++) 558 if (rs->dev[i].data_dev && 559 !test_bit(In_sync, &rs->dev[i].rdev.flags)) 560 raid_param_cnt++; /* for rebuilds */ 561 562 raid_param_cnt += (hweight64(rs->print_flags) * 2); 563 if (rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC)) 564 raid_param_cnt--; 565 566 DMEMIT("%s %u %u", rs->raid_type->name, 567 raid_param_cnt, rs->md.chunk_sectors); 568 569 if ((rs->print_flags & DMPF_SYNC) && 570 (rs->md.recovery_cp == MaxSector)) 571 DMEMIT(" sync"); 572 if (rs->print_flags & DMPF_NOSYNC) 573 DMEMIT(" nosync"); 574 575 for (i = 0; i < rs->md.raid_disks; i++) 576 if (rs->dev[i].data_dev && 577 !test_bit(In_sync, &rs->dev[i].rdev.flags)) 578 DMEMIT(" rebuild %u", i); 579 580 if (rs->print_flags & DMPF_DAEMON_SLEEP) 581 DMEMIT(" daemon_sleep %lu", 582 rs->md.bitmap_info.daemon_sleep); 583 584 if (rs->print_flags & DMPF_MIN_RECOVERY_RATE) 585 DMEMIT(" min_recovery_rate %d", rs->md.sync_speed_min); 586 587 if (rs->print_flags & DMPF_MAX_RECOVERY_RATE) 588 DMEMIT(" max_recovery_rate %d", rs->md.sync_speed_max); 589 590 if (rs->print_flags & DMPF_MAX_WRITE_BEHIND) 591 DMEMIT(" max_write_behind %lu", 592 rs->md.bitmap_info.max_write_behind); 593 594 if (rs->print_flags & DMPF_STRIPE_CACHE) { 595 raid5_conf_t *conf = rs->md.private; 596 597 /* convert from kiB to sectors */ 598 DMEMIT(" stripe_cache %d", 599 conf ? conf->max_nr_stripes * 2 : 0); 600 } 601 602 DMEMIT(" %d", rs->md.raid_disks); 603 for (i = 0; i < rs->md.raid_disks; i++) { 604 DMEMIT(" -"); /* metadata device */ 605 606 if (rs->dev[i].data_dev) 607 DMEMIT(" %s", rs->dev[i].data_dev->name); 608 else 609 DMEMIT(" -"); 610 } 611 } 612 613 return 0; 614 } 615 616 static int raid_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) 617 { 618 struct raid_set *rs = ti->private; 619 unsigned i; 620 int ret = 0; 621 622 for (i = 0; !ret && i < rs->md.raid_disks; i++) 623 if (rs->dev[i].data_dev) 624 ret = fn(ti, 625 rs->dev[i].data_dev, 626 0, /* No offset on data devs */ 627 rs->md.dev_sectors, 628 data); 629 630 return ret; 631 } 632 633 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits) 634 { 635 struct raid_set *rs = ti->private; 636 unsigned chunk_size = rs->md.chunk_sectors << 9; 637 raid5_conf_t *conf = rs->md.private; 638 639 blk_limits_io_min(limits, chunk_size); 640 blk_limits_io_opt(limits, chunk_size * (conf->raid_disks - conf->max_degraded)); 641 } 642 643 static void raid_presuspend(struct dm_target *ti) 644 { 645 struct raid_set *rs = ti->private; 646 647 md_stop_writes(&rs->md); 648 } 649 650 static void raid_postsuspend(struct dm_target *ti) 651 { 652 struct raid_set *rs = ti->private; 653 654 mddev_suspend(&rs->md); 655 } 656 657 static void raid_resume(struct dm_target *ti) 658 { 659 struct raid_set *rs = ti->private; 660 661 mddev_resume(&rs->md); 662 } 663 664 static struct target_type raid_target = { 665 .name = "raid", 666 .version = {1, 0, 0}, 667 .module = THIS_MODULE, 668 .ctr = raid_ctr, 669 .dtr = raid_dtr, 670 .map = raid_map, 671 .status = raid_status, 672 .iterate_devices = raid_iterate_devices, 673 .io_hints = raid_io_hints, 674 .presuspend = raid_presuspend, 675 .postsuspend = raid_postsuspend, 676 .resume = raid_resume, 677 }; 678 679 static int __init dm_raid_init(void) 680 { 681 return dm_register_target(&raid_target); 682 } 683 684 static void __exit dm_raid_exit(void) 685 { 686 dm_unregister_target(&raid_target); 687 } 688 689 module_init(dm_raid_init); 690 module_exit(dm_raid_exit); 691 692 MODULE_DESCRIPTION(DM_NAME " raid4/5/6 target"); 693 MODULE_ALIAS("dm-raid4"); 694 MODULE_ALIAS("dm-raid5"); 695 MODULE_ALIAS("dm-raid6"); 696 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>"); 697 MODULE_LICENSE("GPL"); 698