1 /* 2 * Copyright (C) 2003 Sistina Software Limited. 3 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved. 4 * 5 * This file is released under the GPL. 6 */ 7 8 #include "dm-bio-record.h" 9 10 #include <linux/init.h> 11 #include <linux/mempool.h> 12 #include <linux/module.h> 13 #include <linux/pagemap.h> 14 #include <linux/slab.h> 15 #include <linux/workqueue.h> 16 #include <linux/device-mapper.h> 17 #include <linux/dm-io.h> 18 #include <linux/dm-dirty-log.h> 19 #include <linux/dm-kcopyd.h> 20 #include <linux/dm-region-hash.h> 21 22 #define DM_MSG_PREFIX "raid1" 23 24 #define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */ 25 26 #define DM_RAID1_HANDLE_ERRORS 0x01 27 #define DM_RAID1_KEEP_LOG 0x02 28 #define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS) 29 #define keep_log(p) ((p)->features & DM_RAID1_KEEP_LOG) 30 31 static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped); 32 33 /*----------------------------------------------------------------- 34 * Mirror set structures. 35 *---------------------------------------------------------------*/ 36 enum dm_raid1_error { 37 DM_RAID1_WRITE_ERROR, 38 DM_RAID1_FLUSH_ERROR, 39 DM_RAID1_SYNC_ERROR, 40 DM_RAID1_READ_ERROR 41 }; 42 43 struct mirror { 44 struct mirror_set *ms; 45 atomic_t error_count; 46 unsigned long error_type; 47 struct dm_dev *dev; 48 sector_t offset; 49 }; 50 51 struct mirror_set { 52 struct dm_target *ti; 53 struct list_head list; 54 55 uint64_t features; 56 57 spinlock_t lock; /* protects the lists */ 58 struct bio_list reads; 59 struct bio_list writes; 60 struct bio_list failures; 61 struct bio_list holds; /* bios are waiting until suspend */ 62 63 struct dm_region_hash *rh; 64 struct dm_kcopyd_client *kcopyd_client; 65 struct dm_io_client *io_client; 66 67 /* recovery */ 68 region_t nr_regions; 69 int in_sync; 70 int log_failure; 71 int leg_failure; 72 atomic_t suspend; 73 74 atomic_t default_mirror; /* Default mirror */ 75 76 struct workqueue_struct *kmirrord_wq; 77 struct work_struct kmirrord_work; 78 struct timer_list timer; 79 unsigned long timer_pending; 80 81 struct work_struct trigger_event; 82 83 unsigned nr_mirrors; 84 struct mirror mirror[0]; 85 }; 86 87 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(raid1_resync_throttle, 88 "A percentage of time allocated for raid resynchronization"); 89 90 static void wakeup_mirrord(void *context) 91 { 92 struct mirror_set *ms = context; 93 94 queue_work(ms->kmirrord_wq, &ms->kmirrord_work); 95 } 96 97 static void delayed_wake_fn(struct timer_list *t) 98 { 99 struct mirror_set *ms = from_timer(ms, t, timer); 100 101 clear_bit(0, &ms->timer_pending); 102 wakeup_mirrord(ms); 103 } 104 105 static void delayed_wake(struct mirror_set *ms) 106 { 107 if (test_and_set_bit(0, &ms->timer_pending)) 108 return; 109 110 ms->timer.expires = jiffies + HZ / 5; 111 add_timer(&ms->timer); 112 } 113 114 static void wakeup_all_recovery_waiters(void *context) 115 { 116 wake_up_all(&_kmirrord_recovery_stopped); 117 } 118 119 static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw) 120 { 121 unsigned long flags; 122 int should_wake = 0; 123 struct bio_list *bl; 124 125 bl = (rw == WRITE) ? &ms->writes : &ms->reads; 126 spin_lock_irqsave(&ms->lock, flags); 127 should_wake = !(bl->head); 128 bio_list_add(bl, bio); 129 spin_unlock_irqrestore(&ms->lock, flags); 130 131 if (should_wake) 132 wakeup_mirrord(ms); 133 } 134 135 static void dispatch_bios(void *context, struct bio_list *bio_list) 136 { 137 struct mirror_set *ms = context; 138 struct bio *bio; 139 140 while ((bio = bio_list_pop(bio_list))) 141 queue_bio(ms, bio, WRITE); 142 } 143 144 struct dm_raid1_bio_record { 145 struct mirror *m; 146 /* if details->bi_disk == NULL, details were not saved */ 147 struct dm_bio_details details; 148 region_t write_region; 149 }; 150 151 /* 152 * Every mirror should look like this one. 153 */ 154 #define DEFAULT_MIRROR 0 155 156 /* 157 * This is yucky. We squirrel the mirror struct away inside 158 * bi_next for read/write buffers. This is safe since the bh 159 * doesn't get submitted to the lower levels of block layer. 160 */ 161 static struct mirror *bio_get_m(struct bio *bio) 162 { 163 return (struct mirror *) bio->bi_next; 164 } 165 166 static void bio_set_m(struct bio *bio, struct mirror *m) 167 { 168 bio->bi_next = (struct bio *) m; 169 } 170 171 static struct mirror *get_default_mirror(struct mirror_set *ms) 172 { 173 return &ms->mirror[atomic_read(&ms->default_mirror)]; 174 } 175 176 static void set_default_mirror(struct mirror *m) 177 { 178 struct mirror_set *ms = m->ms; 179 struct mirror *m0 = &(ms->mirror[0]); 180 181 atomic_set(&ms->default_mirror, m - m0); 182 } 183 184 static struct mirror *get_valid_mirror(struct mirror_set *ms) 185 { 186 struct mirror *m; 187 188 for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++) 189 if (!atomic_read(&m->error_count)) 190 return m; 191 192 return NULL; 193 } 194 195 /* fail_mirror 196 * @m: mirror device to fail 197 * @error_type: one of the enum's, DM_RAID1_*_ERROR 198 * 199 * If errors are being handled, record the type of 200 * error encountered for this device. If this type 201 * of error has already been recorded, we can return; 202 * otherwise, we must signal userspace by triggering 203 * an event. Additionally, if the device is the 204 * primary device, we must choose a new primary, but 205 * only if the mirror is in-sync. 206 * 207 * This function must not block. 208 */ 209 static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type) 210 { 211 struct mirror_set *ms = m->ms; 212 struct mirror *new; 213 214 ms->leg_failure = 1; 215 216 /* 217 * error_count is used for nothing more than a 218 * simple way to tell if a device has encountered 219 * errors. 220 */ 221 atomic_inc(&m->error_count); 222 223 if (test_and_set_bit(error_type, &m->error_type)) 224 return; 225 226 if (!errors_handled(ms)) 227 return; 228 229 if (m != get_default_mirror(ms)) 230 goto out; 231 232 if (!ms->in_sync && !keep_log(ms)) { 233 /* 234 * Better to issue requests to same failing device 235 * than to risk returning corrupt data. 236 */ 237 DMERR("Primary mirror (%s) failed while out-of-sync: " 238 "Reads may fail.", m->dev->name); 239 goto out; 240 } 241 242 new = get_valid_mirror(ms); 243 if (new) 244 set_default_mirror(new); 245 else 246 DMWARN("All sides of mirror have failed."); 247 248 out: 249 schedule_work(&ms->trigger_event); 250 } 251 252 static int mirror_flush(struct dm_target *ti) 253 { 254 struct mirror_set *ms = ti->private; 255 unsigned long error_bits; 256 257 unsigned int i; 258 struct dm_io_region io[ms->nr_mirrors]; 259 struct mirror *m; 260 struct dm_io_request io_req = { 261 .bi_op = REQ_OP_WRITE, 262 .bi_op_flags = REQ_PREFLUSH | REQ_SYNC, 263 .mem.type = DM_IO_KMEM, 264 .mem.ptr.addr = NULL, 265 .client = ms->io_client, 266 }; 267 268 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) { 269 io[i].bdev = m->dev->bdev; 270 io[i].sector = 0; 271 io[i].count = 0; 272 } 273 274 error_bits = -1; 275 dm_io(&io_req, ms->nr_mirrors, io, &error_bits); 276 if (unlikely(error_bits != 0)) { 277 for (i = 0; i < ms->nr_mirrors; i++) 278 if (test_bit(i, &error_bits)) 279 fail_mirror(ms->mirror + i, 280 DM_RAID1_FLUSH_ERROR); 281 return -EIO; 282 } 283 284 return 0; 285 } 286 287 /*----------------------------------------------------------------- 288 * Recovery. 289 * 290 * When a mirror is first activated we may find that some regions 291 * are in the no-sync state. We have to recover these by 292 * recopying from the default mirror to all the others. 293 *---------------------------------------------------------------*/ 294 static void recovery_complete(int read_err, unsigned long write_err, 295 void *context) 296 { 297 struct dm_region *reg = context; 298 struct mirror_set *ms = dm_rh_region_context(reg); 299 int m, bit = 0; 300 301 if (read_err) { 302 /* Read error means the failure of default mirror. */ 303 DMERR_LIMIT("Unable to read primary mirror during recovery"); 304 fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR); 305 } 306 307 if (write_err) { 308 DMERR_LIMIT("Write error during recovery (error = 0x%lx)", 309 write_err); 310 /* 311 * Bits correspond to devices (excluding default mirror). 312 * The default mirror cannot change during recovery. 313 */ 314 for (m = 0; m < ms->nr_mirrors; m++) { 315 if (&ms->mirror[m] == get_default_mirror(ms)) 316 continue; 317 if (test_bit(bit, &write_err)) 318 fail_mirror(ms->mirror + m, 319 DM_RAID1_SYNC_ERROR); 320 bit++; 321 } 322 } 323 324 dm_rh_recovery_end(reg, !(read_err || write_err)); 325 } 326 327 static int recover(struct mirror_set *ms, struct dm_region *reg) 328 { 329 int r; 330 unsigned i; 331 struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest; 332 struct mirror *m; 333 unsigned long flags = 0; 334 region_t key = dm_rh_get_region_key(reg); 335 sector_t region_size = dm_rh_get_region_size(ms->rh); 336 337 /* fill in the source */ 338 m = get_default_mirror(ms); 339 from.bdev = m->dev->bdev; 340 from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key); 341 if (key == (ms->nr_regions - 1)) { 342 /* 343 * The final region may be smaller than 344 * region_size. 345 */ 346 from.count = ms->ti->len & (region_size - 1); 347 if (!from.count) 348 from.count = region_size; 349 } else 350 from.count = region_size; 351 352 /* fill in the destinations */ 353 for (i = 0, dest = to; i < ms->nr_mirrors; i++) { 354 if (&ms->mirror[i] == get_default_mirror(ms)) 355 continue; 356 357 m = ms->mirror + i; 358 dest->bdev = m->dev->bdev; 359 dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key); 360 dest->count = from.count; 361 dest++; 362 } 363 364 /* hand to kcopyd */ 365 if (!errors_handled(ms)) 366 set_bit(DM_KCOPYD_IGNORE_ERROR, &flags); 367 368 r = dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to, 369 flags, recovery_complete, reg); 370 371 return r; 372 } 373 374 static void reset_ms_flags(struct mirror_set *ms) 375 { 376 unsigned int m; 377 378 ms->leg_failure = 0; 379 for (m = 0; m < ms->nr_mirrors; m++) { 380 atomic_set(&(ms->mirror[m].error_count), 0); 381 ms->mirror[m].error_type = 0; 382 } 383 } 384 385 static void do_recovery(struct mirror_set *ms) 386 { 387 struct dm_region *reg; 388 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 389 int r; 390 391 /* 392 * Start quiescing some regions. 393 */ 394 dm_rh_recovery_prepare(ms->rh); 395 396 /* 397 * Copy any already quiesced regions. 398 */ 399 while ((reg = dm_rh_recovery_start(ms->rh))) { 400 r = recover(ms, reg); 401 if (r) 402 dm_rh_recovery_end(reg, 0); 403 } 404 405 /* 406 * Update the in sync flag. 407 */ 408 if (!ms->in_sync && 409 (log->type->get_sync_count(log) == ms->nr_regions)) { 410 /* the sync is complete */ 411 dm_table_event(ms->ti->table); 412 ms->in_sync = 1; 413 reset_ms_flags(ms); 414 } 415 } 416 417 /*----------------------------------------------------------------- 418 * Reads 419 *---------------------------------------------------------------*/ 420 static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector) 421 { 422 struct mirror *m = get_default_mirror(ms); 423 424 do { 425 if (likely(!atomic_read(&m->error_count))) 426 return m; 427 428 if (m-- == ms->mirror) 429 m += ms->nr_mirrors; 430 } while (m != get_default_mirror(ms)); 431 432 return NULL; 433 } 434 435 static int default_ok(struct mirror *m) 436 { 437 struct mirror *default_mirror = get_default_mirror(m->ms); 438 439 return !atomic_read(&default_mirror->error_count); 440 } 441 442 static int mirror_available(struct mirror_set *ms, struct bio *bio) 443 { 444 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 445 region_t region = dm_rh_bio_to_region(ms->rh, bio); 446 447 if (log->type->in_sync(log, region, 0)) 448 return choose_mirror(ms, bio->bi_iter.bi_sector) ? 1 : 0; 449 450 return 0; 451 } 452 453 /* 454 * remap a buffer to a particular mirror. 455 */ 456 static sector_t map_sector(struct mirror *m, struct bio *bio) 457 { 458 if (unlikely(!bio->bi_iter.bi_size)) 459 return 0; 460 return m->offset + dm_target_offset(m->ms->ti, bio->bi_iter.bi_sector); 461 } 462 463 static void map_bio(struct mirror *m, struct bio *bio) 464 { 465 bio_set_dev(bio, m->dev->bdev); 466 bio->bi_iter.bi_sector = map_sector(m, bio); 467 } 468 469 static void map_region(struct dm_io_region *io, struct mirror *m, 470 struct bio *bio) 471 { 472 io->bdev = m->dev->bdev; 473 io->sector = map_sector(m, bio); 474 io->count = bio_sectors(bio); 475 } 476 477 static void hold_bio(struct mirror_set *ms, struct bio *bio) 478 { 479 /* 480 * Lock is required to avoid race condition during suspend 481 * process. 482 */ 483 spin_lock_irq(&ms->lock); 484 485 if (atomic_read(&ms->suspend)) { 486 spin_unlock_irq(&ms->lock); 487 488 /* 489 * If device is suspended, complete the bio. 490 */ 491 if (dm_noflush_suspending(ms->ti)) 492 bio->bi_status = BLK_STS_DM_REQUEUE; 493 else 494 bio->bi_status = BLK_STS_IOERR; 495 496 bio_endio(bio); 497 return; 498 } 499 500 /* 501 * Hold bio until the suspend is complete. 502 */ 503 bio_list_add(&ms->holds, bio); 504 spin_unlock_irq(&ms->lock); 505 } 506 507 /*----------------------------------------------------------------- 508 * Reads 509 *---------------------------------------------------------------*/ 510 static void read_callback(unsigned long error, void *context) 511 { 512 struct bio *bio = context; 513 struct mirror *m; 514 515 m = bio_get_m(bio); 516 bio_set_m(bio, NULL); 517 518 if (likely(!error)) { 519 bio_endio(bio); 520 return; 521 } 522 523 fail_mirror(m, DM_RAID1_READ_ERROR); 524 525 if (likely(default_ok(m)) || mirror_available(m->ms, bio)) { 526 DMWARN_LIMIT("Read failure on mirror device %s. " 527 "Trying alternative device.", 528 m->dev->name); 529 queue_bio(m->ms, bio, bio_data_dir(bio)); 530 return; 531 } 532 533 DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.", 534 m->dev->name); 535 bio_io_error(bio); 536 } 537 538 /* Asynchronous read. */ 539 static void read_async_bio(struct mirror *m, struct bio *bio) 540 { 541 struct dm_io_region io; 542 struct dm_io_request io_req = { 543 .bi_op = REQ_OP_READ, 544 .bi_op_flags = 0, 545 .mem.type = DM_IO_BIO, 546 .mem.ptr.bio = bio, 547 .notify.fn = read_callback, 548 .notify.context = bio, 549 .client = m->ms->io_client, 550 }; 551 552 map_region(&io, m, bio); 553 bio_set_m(bio, m); 554 BUG_ON(dm_io(&io_req, 1, &io, NULL)); 555 } 556 557 static inline int region_in_sync(struct mirror_set *ms, region_t region, 558 int may_block) 559 { 560 int state = dm_rh_get_state(ms->rh, region, may_block); 561 return state == DM_RH_CLEAN || state == DM_RH_DIRTY; 562 } 563 564 static void do_reads(struct mirror_set *ms, struct bio_list *reads) 565 { 566 region_t region; 567 struct bio *bio; 568 struct mirror *m; 569 570 while ((bio = bio_list_pop(reads))) { 571 region = dm_rh_bio_to_region(ms->rh, bio); 572 m = get_default_mirror(ms); 573 574 /* 575 * We can only read balance if the region is in sync. 576 */ 577 if (likely(region_in_sync(ms, region, 1))) 578 m = choose_mirror(ms, bio->bi_iter.bi_sector); 579 else if (m && atomic_read(&m->error_count)) 580 m = NULL; 581 582 if (likely(m)) 583 read_async_bio(m, bio); 584 else 585 bio_io_error(bio); 586 } 587 } 588 589 /*----------------------------------------------------------------- 590 * Writes. 591 * 592 * We do different things with the write io depending on the 593 * state of the region that it's in: 594 * 595 * SYNC: increment pending, use kcopyd to write to *all* mirrors 596 * RECOVERING: delay the io until recovery completes 597 * NOSYNC: increment pending, just write to the default mirror 598 *---------------------------------------------------------------*/ 599 600 601 static void write_callback(unsigned long error, void *context) 602 { 603 unsigned i; 604 struct bio *bio = (struct bio *) context; 605 struct mirror_set *ms; 606 int should_wake = 0; 607 unsigned long flags; 608 609 ms = bio_get_m(bio)->ms; 610 bio_set_m(bio, NULL); 611 612 /* 613 * NOTE: We don't decrement the pending count here, 614 * instead it is done by the targets endio function. 615 * This way we handle both writes to SYNC and NOSYNC 616 * regions with the same code. 617 */ 618 if (likely(!error)) { 619 bio_endio(bio); 620 return; 621 } 622 623 /* 624 * If the bio is discard, return an error, but do not 625 * degrade the array. 626 */ 627 if (bio_op(bio) == REQ_OP_DISCARD) { 628 bio->bi_status = BLK_STS_NOTSUPP; 629 bio_endio(bio); 630 return; 631 } 632 633 for (i = 0; i < ms->nr_mirrors; i++) 634 if (test_bit(i, &error)) 635 fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR); 636 637 /* 638 * Need to raise event. Since raising 639 * events can block, we need to do it in 640 * the main thread. 641 */ 642 spin_lock_irqsave(&ms->lock, flags); 643 if (!ms->failures.head) 644 should_wake = 1; 645 bio_list_add(&ms->failures, bio); 646 spin_unlock_irqrestore(&ms->lock, flags); 647 if (should_wake) 648 wakeup_mirrord(ms); 649 } 650 651 static void do_write(struct mirror_set *ms, struct bio *bio) 652 { 653 unsigned int i; 654 struct dm_io_region io[ms->nr_mirrors], *dest = io; 655 struct mirror *m; 656 struct dm_io_request io_req = { 657 .bi_op = REQ_OP_WRITE, 658 .bi_op_flags = bio->bi_opf & (REQ_FUA | REQ_PREFLUSH), 659 .mem.type = DM_IO_BIO, 660 .mem.ptr.bio = bio, 661 .notify.fn = write_callback, 662 .notify.context = bio, 663 .client = ms->io_client, 664 }; 665 666 if (bio_op(bio) == REQ_OP_DISCARD) { 667 io_req.bi_op = REQ_OP_DISCARD; 668 io_req.mem.type = DM_IO_KMEM; 669 io_req.mem.ptr.addr = NULL; 670 } 671 672 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) 673 map_region(dest++, m, bio); 674 675 /* 676 * Use default mirror because we only need it to retrieve the reference 677 * to the mirror set in write_callback(). 678 */ 679 bio_set_m(bio, get_default_mirror(ms)); 680 681 BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL)); 682 } 683 684 static void do_writes(struct mirror_set *ms, struct bio_list *writes) 685 { 686 int state; 687 struct bio *bio; 688 struct bio_list sync, nosync, recover, *this_list = NULL; 689 struct bio_list requeue; 690 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 691 region_t region; 692 693 if (!writes->head) 694 return; 695 696 /* 697 * Classify each write. 698 */ 699 bio_list_init(&sync); 700 bio_list_init(&nosync); 701 bio_list_init(&recover); 702 bio_list_init(&requeue); 703 704 while ((bio = bio_list_pop(writes))) { 705 if ((bio->bi_opf & REQ_PREFLUSH) || 706 (bio_op(bio) == REQ_OP_DISCARD)) { 707 bio_list_add(&sync, bio); 708 continue; 709 } 710 711 region = dm_rh_bio_to_region(ms->rh, bio); 712 713 if (log->type->is_remote_recovering && 714 log->type->is_remote_recovering(log, region)) { 715 bio_list_add(&requeue, bio); 716 continue; 717 } 718 719 state = dm_rh_get_state(ms->rh, region, 1); 720 switch (state) { 721 case DM_RH_CLEAN: 722 case DM_RH_DIRTY: 723 this_list = &sync; 724 break; 725 726 case DM_RH_NOSYNC: 727 this_list = &nosync; 728 break; 729 730 case DM_RH_RECOVERING: 731 this_list = &recover; 732 break; 733 } 734 735 bio_list_add(this_list, bio); 736 } 737 738 /* 739 * Add bios that are delayed due to remote recovery 740 * back on to the write queue 741 */ 742 if (unlikely(requeue.head)) { 743 spin_lock_irq(&ms->lock); 744 bio_list_merge(&ms->writes, &requeue); 745 spin_unlock_irq(&ms->lock); 746 delayed_wake(ms); 747 } 748 749 /* 750 * Increment the pending counts for any regions that will 751 * be written to (writes to recover regions are going to 752 * be delayed). 753 */ 754 dm_rh_inc_pending(ms->rh, &sync); 755 dm_rh_inc_pending(ms->rh, &nosync); 756 757 /* 758 * If the flush fails on a previous call and succeeds here, 759 * we must not reset the log_failure variable. We need 760 * userspace interaction to do that. 761 */ 762 ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure; 763 764 /* 765 * Dispatch io. 766 */ 767 if (unlikely(ms->log_failure) && errors_handled(ms)) { 768 spin_lock_irq(&ms->lock); 769 bio_list_merge(&ms->failures, &sync); 770 spin_unlock_irq(&ms->lock); 771 wakeup_mirrord(ms); 772 } else 773 while ((bio = bio_list_pop(&sync))) 774 do_write(ms, bio); 775 776 while ((bio = bio_list_pop(&recover))) 777 dm_rh_delay(ms->rh, bio); 778 779 while ((bio = bio_list_pop(&nosync))) { 780 if (unlikely(ms->leg_failure) && errors_handled(ms) && !keep_log(ms)) { 781 spin_lock_irq(&ms->lock); 782 bio_list_add(&ms->failures, bio); 783 spin_unlock_irq(&ms->lock); 784 wakeup_mirrord(ms); 785 } else { 786 map_bio(get_default_mirror(ms), bio); 787 generic_make_request(bio); 788 } 789 } 790 } 791 792 static void do_failures(struct mirror_set *ms, struct bio_list *failures) 793 { 794 struct bio *bio; 795 796 if (likely(!failures->head)) 797 return; 798 799 /* 800 * If the log has failed, unattempted writes are being 801 * put on the holds list. We can't issue those writes 802 * until a log has been marked, so we must store them. 803 * 804 * If a 'noflush' suspend is in progress, we can requeue 805 * the I/O's to the core. This give userspace a chance 806 * to reconfigure the mirror, at which point the core 807 * will reissue the writes. If the 'noflush' flag is 808 * not set, we have no choice but to return errors. 809 * 810 * Some writes on the failures list may have been 811 * submitted before the log failure and represent a 812 * failure to write to one of the devices. It is ok 813 * for us to treat them the same and requeue them 814 * as well. 815 */ 816 while ((bio = bio_list_pop(failures))) { 817 if (!ms->log_failure) { 818 ms->in_sync = 0; 819 dm_rh_mark_nosync(ms->rh, bio); 820 } 821 822 /* 823 * If all the legs are dead, fail the I/O. 824 * If the device has failed and keep_log is enabled, 825 * fail the I/O. 826 * 827 * If we have been told to handle errors, and keep_log 828 * isn't enabled, hold the bio and wait for userspace to 829 * deal with the problem. 830 * 831 * Otherwise pretend that the I/O succeeded. (This would 832 * be wrong if the failed leg returned after reboot and 833 * got replicated back to the good legs.) 834 */ 835 if (unlikely(!get_valid_mirror(ms) || (keep_log(ms) && ms->log_failure))) 836 bio_io_error(bio); 837 else if (errors_handled(ms) && !keep_log(ms)) 838 hold_bio(ms, bio); 839 else 840 bio_endio(bio); 841 } 842 } 843 844 static void trigger_event(struct work_struct *work) 845 { 846 struct mirror_set *ms = 847 container_of(work, struct mirror_set, trigger_event); 848 849 dm_table_event(ms->ti->table); 850 } 851 852 /*----------------------------------------------------------------- 853 * kmirrord 854 *---------------------------------------------------------------*/ 855 static void do_mirror(struct work_struct *work) 856 { 857 struct mirror_set *ms = container_of(work, struct mirror_set, 858 kmirrord_work); 859 struct bio_list reads, writes, failures; 860 unsigned long flags; 861 862 spin_lock_irqsave(&ms->lock, flags); 863 reads = ms->reads; 864 writes = ms->writes; 865 failures = ms->failures; 866 bio_list_init(&ms->reads); 867 bio_list_init(&ms->writes); 868 bio_list_init(&ms->failures); 869 spin_unlock_irqrestore(&ms->lock, flags); 870 871 dm_rh_update_states(ms->rh, errors_handled(ms)); 872 do_recovery(ms); 873 do_reads(ms, &reads); 874 do_writes(ms, &writes); 875 do_failures(ms, &failures); 876 } 877 878 /*----------------------------------------------------------------- 879 * Target functions 880 *---------------------------------------------------------------*/ 881 static struct mirror_set *alloc_context(unsigned int nr_mirrors, 882 uint32_t region_size, 883 struct dm_target *ti, 884 struct dm_dirty_log *dl) 885 { 886 size_t len; 887 struct mirror_set *ms = NULL; 888 889 len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors); 890 891 ms = kzalloc(len, GFP_KERNEL); 892 if (!ms) { 893 ti->error = "Cannot allocate mirror context"; 894 return NULL; 895 } 896 897 spin_lock_init(&ms->lock); 898 bio_list_init(&ms->reads); 899 bio_list_init(&ms->writes); 900 bio_list_init(&ms->failures); 901 bio_list_init(&ms->holds); 902 903 ms->ti = ti; 904 ms->nr_mirrors = nr_mirrors; 905 ms->nr_regions = dm_sector_div_up(ti->len, region_size); 906 ms->in_sync = 0; 907 ms->log_failure = 0; 908 ms->leg_failure = 0; 909 atomic_set(&ms->suspend, 0); 910 atomic_set(&ms->default_mirror, DEFAULT_MIRROR); 911 912 ms->io_client = dm_io_client_create(); 913 if (IS_ERR(ms->io_client)) { 914 ti->error = "Error creating dm_io client"; 915 kfree(ms); 916 return NULL; 917 } 918 919 ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord, 920 wakeup_all_recovery_waiters, 921 ms->ti->begin, MAX_RECOVERY, 922 dl, region_size, ms->nr_regions); 923 if (IS_ERR(ms->rh)) { 924 ti->error = "Error creating dirty region hash"; 925 dm_io_client_destroy(ms->io_client); 926 kfree(ms); 927 return NULL; 928 } 929 930 return ms; 931 } 932 933 static void free_context(struct mirror_set *ms, struct dm_target *ti, 934 unsigned int m) 935 { 936 while (m--) 937 dm_put_device(ti, ms->mirror[m].dev); 938 939 dm_io_client_destroy(ms->io_client); 940 dm_region_hash_destroy(ms->rh); 941 kfree(ms); 942 } 943 944 static int get_mirror(struct mirror_set *ms, struct dm_target *ti, 945 unsigned int mirror, char **argv) 946 { 947 unsigned long long offset; 948 char dummy; 949 int ret; 950 951 if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1) { 952 ti->error = "Invalid offset"; 953 return -EINVAL; 954 } 955 956 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), 957 &ms->mirror[mirror].dev); 958 if (ret) { 959 ti->error = "Device lookup failure"; 960 return ret; 961 } 962 963 ms->mirror[mirror].ms = ms; 964 atomic_set(&(ms->mirror[mirror].error_count), 0); 965 ms->mirror[mirror].error_type = 0; 966 ms->mirror[mirror].offset = offset; 967 968 return 0; 969 } 970 971 /* 972 * Create dirty log: log_type #log_params <log_params> 973 */ 974 static struct dm_dirty_log *create_dirty_log(struct dm_target *ti, 975 unsigned argc, char **argv, 976 unsigned *args_used) 977 { 978 unsigned param_count; 979 struct dm_dirty_log *dl; 980 char dummy; 981 982 if (argc < 2) { 983 ti->error = "Insufficient mirror log arguments"; 984 return NULL; 985 } 986 987 if (sscanf(argv[1], "%u%c", ¶m_count, &dummy) != 1) { 988 ti->error = "Invalid mirror log argument count"; 989 return NULL; 990 } 991 992 *args_used = 2 + param_count; 993 994 if (argc < *args_used) { 995 ti->error = "Insufficient mirror log arguments"; 996 return NULL; 997 } 998 999 dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count, 1000 argv + 2); 1001 if (!dl) { 1002 ti->error = "Error creating mirror dirty log"; 1003 return NULL; 1004 } 1005 1006 return dl; 1007 } 1008 1009 static int parse_features(struct mirror_set *ms, unsigned argc, char **argv, 1010 unsigned *args_used) 1011 { 1012 unsigned num_features; 1013 struct dm_target *ti = ms->ti; 1014 char dummy; 1015 int i; 1016 1017 *args_used = 0; 1018 1019 if (!argc) 1020 return 0; 1021 1022 if (sscanf(argv[0], "%u%c", &num_features, &dummy) != 1) { 1023 ti->error = "Invalid number of features"; 1024 return -EINVAL; 1025 } 1026 1027 argc--; 1028 argv++; 1029 (*args_used)++; 1030 1031 if (num_features > argc) { 1032 ti->error = "Not enough arguments to support feature count"; 1033 return -EINVAL; 1034 } 1035 1036 for (i = 0; i < num_features; i++) { 1037 if (!strcmp("handle_errors", argv[0])) 1038 ms->features |= DM_RAID1_HANDLE_ERRORS; 1039 else if (!strcmp("keep_log", argv[0])) 1040 ms->features |= DM_RAID1_KEEP_LOG; 1041 else { 1042 ti->error = "Unrecognised feature requested"; 1043 return -EINVAL; 1044 } 1045 1046 argc--; 1047 argv++; 1048 (*args_used)++; 1049 } 1050 if (!errors_handled(ms) && keep_log(ms)) { 1051 ti->error = "keep_log feature requires the handle_errors feature"; 1052 return -EINVAL; 1053 } 1054 1055 return 0; 1056 } 1057 1058 /* 1059 * Construct a mirror mapping: 1060 * 1061 * log_type #log_params <log_params> 1062 * #mirrors [mirror_path offset]{2,} 1063 * [#features <features>] 1064 * 1065 * log_type is "core" or "disk" 1066 * #log_params is between 1 and 3 1067 * 1068 * If present, supported features are "handle_errors" and "keep_log". 1069 */ 1070 static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) 1071 { 1072 int r; 1073 unsigned int nr_mirrors, m, args_used; 1074 struct mirror_set *ms; 1075 struct dm_dirty_log *dl; 1076 char dummy; 1077 1078 dl = create_dirty_log(ti, argc, argv, &args_used); 1079 if (!dl) 1080 return -EINVAL; 1081 1082 argv += args_used; 1083 argc -= args_used; 1084 1085 if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 || 1086 nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) { 1087 ti->error = "Invalid number of mirrors"; 1088 dm_dirty_log_destroy(dl); 1089 return -EINVAL; 1090 } 1091 1092 argv++, argc--; 1093 1094 if (argc < nr_mirrors * 2) { 1095 ti->error = "Too few mirror arguments"; 1096 dm_dirty_log_destroy(dl); 1097 return -EINVAL; 1098 } 1099 1100 ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl); 1101 if (!ms) { 1102 dm_dirty_log_destroy(dl); 1103 return -ENOMEM; 1104 } 1105 1106 /* Get the mirror parameter sets */ 1107 for (m = 0; m < nr_mirrors; m++) { 1108 r = get_mirror(ms, ti, m, argv); 1109 if (r) { 1110 free_context(ms, ti, m); 1111 return r; 1112 } 1113 argv += 2; 1114 argc -= 2; 1115 } 1116 1117 ti->private = ms; 1118 1119 r = dm_set_target_max_io_len(ti, dm_rh_get_region_size(ms->rh)); 1120 if (r) 1121 goto err_free_context; 1122 1123 ti->num_flush_bios = 1; 1124 ti->num_discard_bios = 1; 1125 ti->per_io_data_size = sizeof(struct dm_raid1_bio_record); 1126 1127 ms->kmirrord_wq = alloc_workqueue("kmirrord", WQ_MEM_RECLAIM, 0); 1128 if (!ms->kmirrord_wq) { 1129 DMERR("couldn't start kmirrord"); 1130 r = -ENOMEM; 1131 goto err_free_context; 1132 } 1133 INIT_WORK(&ms->kmirrord_work, do_mirror); 1134 timer_setup(&ms->timer, delayed_wake_fn, 0); 1135 ms->timer_pending = 0; 1136 INIT_WORK(&ms->trigger_event, trigger_event); 1137 1138 r = parse_features(ms, argc, argv, &args_used); 1139 if (r) 1140 goto err_destroy_wq; 1141 1142 argv += args_used; 1143 argc -= args_used; 1144 1145 /* 1146 * Any read-balancing addition depends on the 1147 * DM_RAID1_HANDLE_ERRORS flag being present. 1148 * This is because the decision to balance depends 1149 * on the sync state of a region. If the above 1150 * flag is not present, we ignore errors; and 1151 * the sync state may be inaccurate. 1152 */ 1153 1154 if (argc) { 1155 ti->error = "Too many mirror arguments"; 1156 r = -EINVAL; 1157 goto err_destroy_wq; 1158 } 1159 1160 ms->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle); 1161 if (IS_ERR(ms->kcopyd_client)) { 1162 r = PTR_ERR(ms->kcopyd_client); 1163 goto err_destroy_wq; 1164 } 1165 1166 wakeup_mirrord(ms); 1167 return 0; 1168 1169 err_destroy_wq: 1170 destroy_workqueue(ms->kmirrord_wq); 1171 err_free_context: 1172 free_context(ms, ti, ms->nr_mirrors); 1173 return r; 1174 } 1175 1176 static void mirror_dtr(struct dm_target *ti) 1177 { 1178 struct mirror_set *ms = (struct mirror_set *) ti->private; 1179 1180 del_timer_sync(&ms->timer); 1181 flush_workqueue(ms->kmirrord_wq); 1182 flush_work(&ms->trigger_event); 1183 dm_kcopyd_client_destroy(ms->kcopyd_client); 1184 destroy_workqueue(ms->kmirrord_wq); 1185 free_context(ms, ti, ms->nr_mirrors); 1186 } 1187 1188 /* 1189 * Mirror mapping function 1190 */ 1191 static int mirror_map(struct dm_target *ti, struct bio *bio) 1192 { 1193 int r, rw = bio_data_dir(bio); 1194 struct mirror *m; 1195 struct mirror_set *ms = ti->private; 1196 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1197 struct dm_raid1_bio_record *bio_record = 1198 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record)); 1199 1200 bio_record->details.bi_disk = NULL; 1201 1202 if (rw == WRITE) { 1203 /* Save region for mirror_end_io() handler */ 1204 bio_record->write_region = dm_rh_bio_to_region(ms->rh, bio); 1205 queue_bio(ms, bio, rw); 1206 return DM_MAPIO_SUBMITTED; 1207 } 1208 1209 r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0); 1210 if (r < 0 && r != -EWOULDBLOCK) 1211 return DM_MAPIO_KILL; 1212 1213 /* 1214 * If region is not in-sync queue the bio. 1215 */ 1216 if (!r || (r == -EWOULDBLOCK)) { 1217 if (bio->bi_opf & REQ_RAHEAD) 1218 return DM_MAPIO_KILL; 1219 1220 queue_bio(ms, bio, rw); 1221 return DM_MAPIO_SUBMITTED; 1222 } 1223 1224 /* 1225 * The region is in-sync and we can perform reads directly. 1226 * Store enough information so we can retry if it fails. 1227 */ 1228 m = choose_mirror(ms, bio->bi_iter.bi_sector); 1229 if (unlikely(!m)) 1230 return DM_MAPIO_KILL; 1231 1232 dm_bio_record(&bio_record->details, bio); 1233 bio_record->m = m; 1234 1235 map_bio(m, bio); 1236 1237 return DM_MAPIO_REMAPPED; 1238 } 1239 1240 static int mirror_end_io(struct dm_target *ti, struct bio *bio, 1241 blk_status_t *error) 1242 { 1243 int rw = bio_data_dir(bio); 1244 struct mirror_set *ms = (struct mirror_set *) ti->private; 1245 struct mirror *m = NULL; 1246 struct dm_bio_details *bd = NULL; 1247 struct dm_raid1_bio_record *bio_record = 1248 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record)); 1249 1250 /* 1251 * We need to dec pending if this was a write. 1252 */ 1253 if (rw == WRITE) { 1254 if (!(bio->bi_opf & REQ_PREFLUSH) && 1255 bio_op(bio) != REQ_OP_DISCARD) 1256 dm_rh_dec(ms->rh, bio_record->write_region); 1257 return DM_ENDIO_DONE; 1258 } 1259 1260 if (*error == BLK_STS_NOTSUPP) 1261 goto out; 1262 1263 if (bio->bi_opf & REQ_RAHEAD) 1264 goto out; 1265 1266 if (unlikely(*error)) { 1267 if (!bio_record->details.bi_disk) { 1268 /* 1269 * There wasn't enough memory to record necessary 1270 * information for a retry or there was no other 1271 * mirror in-sync. 1272 */ 1273 DMERR_LIMIT("Mirror read failed."); 1274 return DM_ENDIO_DONE; 1275 } 1276 1277 m = bio_record->m; 1278 1279 DMERR("Mirror read failed from %s. Trying alternative device.", 1280 m->dev->name); 1281 1282 fail_mirror(m, DM_RAID1_READ_ERROR); 1283 1284 /* 1285 * A failed read is requeued for another attempt using an intact 1286 * mirror. 1287 */ 1288 if (default_ok(m) || mirror_available(ms, bio)) { 1289 bd = &bio_record->details; 1290 1291 dm_bio_restore(bd, bio); 1292 bio_record->details.bi_disk = NULL; 1293 bio->bi_status = 0; 1294 1295 queue_bio(ms, bio, rw); 1296 return DM_ENDIO_INCOMPLETE; 1297 } 1298 DMERR("All replicated volumes dead, failing I/O"); 1299 } 1300 1301 out: 1302 bio_record->details.bi_disk = NULL; 1303 1304 return DM_ENDIO_DONE; 1305 } 1306 1307 static void mirror_presuspend(struct dm_target *ti) 1308 { 1309 struct mirror_set *ms = (struct mirror_set *) ti->private; 1310 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1311 1312 struct bio_list holds; 1313 struct bio *bio; 1314 1315 atomic_set(&ms->suspend, 1); 1316 1317 /* 1318 * Process bios in the hold list to start recovery waiting 1319 * for bios in the hold list. After the process, no bio has 1320 * a chance to be added in the hold list because ms->suspend 1321 * is set. 1322 */ 1323 spin_lock_irq(&ms->lock); 1324 holds = ms->holds; 1325 bio_list_init(&ms->holds); 1326 spin_unlock_irq(&ms->lock); 1327 1328 while ((bio = bio_list_pop(&holds))) 1329 hold_bio(ms, bio); 1330 1331 /* 1332 * We must finish up all the work that we've 1333 * generated (i.e. recovery work). 1334 */ 1335 dm_rh_stop_recovery(ms->rh); 1336 1337 wait_event(_kmirrord_recovery_stopped, 1338 !dm_rh_recovery_in_flight(ms->rh)); 1339 1340 if (log->type->presuspend && log->type->presuspend(log)) 1341 /* FIXME: need better error handling */ 1342 DMWARN("log presuspend failed"); 1343 1344 /* 1345 * Now that recovery is complete/stopped and the 1346 * delayed bios are queued, we need to wait for 1347 * the worker thread to complete. This way, 1348 * we know that all of our I/O has been pushed. 1349 */ 1350 flush_workqueue(ms->kmirrord_wq); 1351 } 1352 1353 static void mirror_postsuspend(struct dm_target *ti) 1354 { 1355 struct mirror_set *ms = ti->private; 1356 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1357 1358 if (log->type->postsuspend && log->type->postsuspend(log)) 1359 /* FIXME: need better error handling */ 1360 DMWARN("log postsuspend failed"); 1361 } 1362 1363 static void mirror_resume(struct dm_target *ti) 1364 { 1365 struct mirror_set *ms = ti->private; 1366 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1367 1368 atomic_set(&ms->suspend, 0); 1369 if (log->type->resume && log->type->resume(log)) 1370 /* FIXME: need better error handling */ 1371 DMWARN("log resume failed"); 1372 dm_rh_start_recovery(ms->rh); 1373 } 1374 1375 /* 1376 * device_status_char 1377 * @m: mirror device/leg we want the status of 1378 * 1379 * We return one character representing the most severe error 1380 * we have encountered. 1381 * A => Alive - No failures 1382 * D => Dead - A write failure occurred leaving mirror out-of-sync 1383 * S => Sync - A sychronization failure occurred, mirror out-of-sync 1384 * R => Read - A read failure occurred, mirror data unaffected 1385 * 1386 * Returns: <char> 1387 */ 1388 static char device_status_char(struct mirror *m) 1389 { 1390 if (!atomic_read(&(m->error_count))) 1391 return 'A'; 1392 1393 return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' : 1394 (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' : 1395 (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' : 1396 (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U'; 1397 } 1398 1399 1400 static void mirror_status(struct dm_target *ti, status_type_t type, 1401 unsigned status_flags, char *result, unsigned maxlen) 1402 { 1403 unsigned int m, sz = 0; 1404 int num_feature_args = 0; 1405 struct mirror_set *ms = (struct mirror_set *) ti->private; 1406 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1407 char buffer[ms->nr_mirrors + 1]; 1408 1409 switch (type) { 1410 case STATUSTYPE_INFO: 1411 DMEMIT("%d ", ms->nr_mirrors); 1412 for (m = 0; m < ms->nr_mirrors; m++) { 1413 DMEMIT("%s ", ms->mirror[m].dev->name); 1414 buffer[m] = device_status_char(&(ms->mirror[m])); 1415 } 1416 buffer[m] = '\0'; 1417 1418 DMEMIT("%llu/%llu 1 %s ", 1419 (unsigned long long)log->type->get_sync_count(log), 1420 (unsigned long long)ms->nr_regions, buffer); 1421 1422 sz += log->type->status(log, type, result+sz, maxlen-sz); 1423 1424 break; 1425 1426 case STATUSTYPE_TABLE: 1427 sz = log->type->status(log, type, result, maxlen); 1428 1429 DMEMIT("%d", ms->nr_mirrors); 1430 for (m = 0; m < ms->nr_mirrors; m++) 1431 DMEMIT(" %s %llu", ms->mirror[m].dev->name, 1432 (unsigned long long)ms->mirror[m].offset); 1433 1434 num_feature_args += !!errors_handled(ms); 1435 num_feature_args += !!keep_log(ms); 1436 if (num_feature_args) { 1437 DMEMIT(" %d", num_feature_args); 1438 if (errors_handled(ms)) 1439 DMEMIT(" handle_errors"); 1440 if (keep_log(ms)) 1441 DMEMIT(" keep_log"); 1442 } 1443 1444 break; 1445 } 1446 } 1447 1448 static int mirror_iterate_devices(struct dm_target *ti, 1449 iterate_devices_callout_fn fn, void *data) 1450 { 1451 struct mirror_set *ms = ti->private; 1452 int ret = 0; 1453 unsigned i; 1454 1455 for (i = 0; !ret && i < ms->nr_mirrors; i++) 1456 ret = fn(ti, ms->mirror[i].dev, 1457 ms->mirror[i].offset, ti->len, data); 1458 1459 return ret; 1460 } 1461 1462 static struct target_type mirror_target = { 1463 .name = "mirror", 1464 .version = {1, 14, 0}, 1465 .module = THIS_MODULE, 1466 .ctr = mirror_ctr, 1467 .dtr = mirror_dtr, 1468 .map = mirror_map, 1469 .end_io = mirror_end_io, 1470 .presuspend = mirror_presuspend, 1471 .postsuspend = mirror_postsuspend, 1472 .resume = mirror_resume, 1473 .status = mirror_status, 1474 .iterate_devices = mirror_iterate_devices, 1475 }; 1476 1477 static int __init dm_mirror_init(void) 1478 { 1479 int r; 1480 1481 r = dm_register_target(&mirror_target); 1482 if (r < 0) { 1483 DMERR("Failed to register mirror target"); 1484 goto bad_target; 1485 } 1486 1487 return 0; 1488 1489 bad_target: 1490 return r; 1491 } 1492 1493 static void __exit dm_mirror_exit(void) 1494 { 1495 dm_unregister_target(&mirror_target); 1496 } 1497 1498 /* Module hooks */ 1499 module_init(dm_mirror_init); 1500 module_exit(dm_mirror_exit); 1501 1502 MODULE_DESCRIPTION(DM_NAME " mirror target"); 1503 MODULE_AUTHOR("Joe Thornber"); 1504 MODULE_LICENSE("GPL"); 1505