1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Copyright (C) 2003 Sistina Software Limited. 4 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved. 5 * 6 * This file is released under the GPL. 7 */ 8 9#include "dm-bio-record.h" 10 11#include <linux/init.h> 12#include <linux/mempool.h> 13#include <linux/module.h> 14#include <linux/pagemap.h> 15#include <linux/slab.h> 16#include <linux/workqueue.h> 17#include <linux/device-mapper.h> 18#include <linux/dm-io.h> 19#include <linux/dm-dirty-log.h> 20#include <linux/dm-kcopyd.h> 21#include <linux/dm-region-hash.h> 22 23static struct workqueue_struct *dm_raid1_wq; 24 25#define DM_MSG_PREFIX "raid1" 26 27#define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */ 28 29#define MAX_NR_MIRRORS (DM_KCOPYD_MAX_REGIONS + 1) 30 31#define DM_RAID1_HANDLE_ERRORS 0x01 32#define DM_RAID1_KEEP_LOG 0x02 33#define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS) 34#define keep_log(p) ((p)->features & DM_RAID1_KEEP_LOG) 35 36static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped); 37 38/* 39 *--------------------------------------------------------------- 40 * Mirror set structures. 41 *--------------------------------------------------------------- 42 */ 43enum dm_raid1_error { 44 DM_RAID1_WRITE_ERROR, 45 DM_RAID1_FLUSH_ERROR, 46 DM_RAID1_SYNC_ERROR, 47 DM_RAID1_READ_ERROR 48}; 49 50struct mirror { 51 struct mirror_set *ms; 52 atomic_t error_count; 53 unsigned long error_type; 54 struct dm_dev *dev; 55 sector_t offset; 56}; 57 58struct mirror_set { 59 struct dm_target *ti; 60 struct list_head list; 61 62 uint64_t features; 63 64 spinlock_t lock; /* protects the lists */ 65 struct bio_list reads; 66 struct bio_list writes; 67 struct bio_list failures; 68 struct bio_list holds; /* bios are waiting until suspend */ 69 70 struct dm_region_hash *rh; 71 struct dm_kcopyd_client *kcopyd_client; 72 struct dm_io_client *io_client; 73 74 /* recovery */ 75 region_t nr_regions; 76 int in_sync; 77 int log_failure; 78 int leg_failure; 79 atomic_t suspend; 80 81 atomic_t default_mirror; /* Default mirror */ 82 83 struct workqueue_struct *kmirrord_wq; 84 struct work_struct kmirrord_work; 85 struct timer_list timer; 86 unsigned long timer_pending; 87 88 struct work_struct trigger_event; 89 90 unsigned int nr_mirrors; 91 struct mirror mirror[]; 92}; 93 94DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(raid1_resync_throttle, 95 "A percentage of time allocated for raid resynchronization"); 96 97static void wakeup_mirrord(void *context) 98{ 99 struct mirror_set *ms = context; 100 101 queue_work(ms->kmirrord_wq, &ms->kmirrord_work); 102} 103 104static void delayed_wake_fn(struct timer_list *t) 105{ 106 struct mirror_set *ms = from_timer(ms, t, timer); 107 108 clear_bit(0, &ms->timer_pending); 109 wakeup_mirrord(ms); 110} 111 112static void delayed_wake(struct mirror_set *ms) 113{ 114 if (test_and_set_bit(0, &ms->timer_pending)) 115 return; 116 117 ms->timer.expires = jiffies + HZ / 5; 118 add_timer(&ms->timer); 119} 120 121static void wakeup_all_recovery_waiters(void *context) 122{ 123 wake_up_all(&_kmirrord_recovery_stopped); 124} 125 126static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw) 127{ 128 unsigned long flags; 129 int should_wake = 0; 130 struct bio_list *bl; 131 132 bl = (rw == WRITE) ? &ms->writes : &ms->reads; 133 spin_lock_irqsave(&ms->lock, flags); 134 should_wake = !(bl->head); 135 bio_list_add(bl, bio); 136 spin_unlock_irqrestore(&ms->lock, flags); 137 138 if (should_wake) 139 wakeup_mirrord(ms); 140} 141 142static void dispatch_bios(void *context, struct bio_list *bio_list) 143{ 144 struct mirror_set *ms = context; 145 struct bio *bio; 146 147 while ((bio = bio_list_pop(bio_list))) 148 queue_bio(ms, bio, WRITE); 149} 150 151struct dm_raid1_bio_record { 152 struct mirror *m; 153 /* if details->bi_bdev == NULL, details were not saved */ 154 struct dm_bio_details details; 155 region_t write_region; 156}; 157 158/* 159 * Every mirror should look like this one. 160 */ 161#define DEFAULT_MIRROR 0 162 163/* 164 * This is yucky. We squirrel the mirror struct away inside 165 * bi_next for read/write buffers. This is safe since the bh 166 * doesn't get submitted to the lower levels of block layer. 167 */ 168static struct mirror *bio_get_m(struct bio *bio) 169{ 170 return (struct mirror *) bio->bi_next; 171} 172 173static void bio_set_m(struct bio *bio, struct mirror *m) 174{ 175 bio->bi_next = (struct bio *) m; 176} 177 178static struct mirror *get_default_mirror(struct mirror_set *ms) 179{ 180 return &ms->mirror[atomic_read(&ms->default_mirror)]; 181} 182 183static void set_default_mirror(struct mirror *m) 184{ 185 struct mirror_set *ms = m->ms; 186 struct mirror *m0 = &(ms->mirror[0]); 187 188 atomic_set(&ms->default_mirror, m - m0); 189} 190 191static struct mirror *get_valid_mirror(struct mirror_set *ms) 192{ 193 struct mirror *m; 194 195 for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++) 196 if (!atomic_read(&m->error_count)) 197 return m; 198 199 return NULL; 200} 201 202/* fail_mirror 203 * @m: mirror device to fail 204 * @error_type: one of the enum's, DM_RAID1_*_ERROR 205 * 206 * If errors are being handled, record the type of 207 * error encountered for this device. If this type 208 * of error has already been recorded, we can return; 209 * otherwise, we must signal userspace by triggering 210 * an event. Additionally, if the device is the 211 * primary device, we must choose a new primary, but 212 * only if the mirror is in-sync. 213 * 214 * This function must not block. 215 */ 216static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type) 217{ 218 struct mirror_set *ms = m->ms; 219 struct mirror *new; 220 221 ms->leg_failure = 1; 222 223 /* 224 * error_count is used for nothing more than a 225 * simple way to tell if a device has encountered 226 * errors. 227 */ 228 atomic_inc(&m->error_count); 229 230 if (test_and_set_bit(error_type, &m->error_type)) 231 return; 232 233 if (!errors_handled(ms)) 234 return; 235 236 if (m != get_default_mirror(ms)) 237 goto out; 238 239 if (!ms->in_sync && !keep_log(ms)) { 240 /* 241 * Better to issue requests to same failing device 242 * than to risk returning corrupt data. 243 */ 244 DMERR("Primary mirror (%s) failed while out-of-sync: Reads may fail.", 245 m->dev->name); 246 goto out; 247 } 248 249 new = get_valid_mirror(ms); 250 if (new) 251 set_default_mirror(new); 252 else 253 DMWARN("All sides of mirror have failed."); 254 255out: 256 queue_work(dm_raid1_wq, &ms->trigger_event); 257} 258 259static int mirror_flush(struct dm_target *ti) 260{ 261 struct mirror_set *ms = ti->private; 262 unsigned long error_bits; 263 264 unsigned int i; 265 struct dm_io_region io[MAX_NR_MIRRORS]; 266 struct mirror *m; 267 struct dm_io_request io_req = { 268 .bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC, 269 .mem.type = DM_IO_KMEM, 270 .mem.ptr.addr = NULL, 271 .client = ms->io_client, 272 }; 273 274 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) { 275 io[i].bdev = m->dev->bdev; 276 io[i].sector = 0; 277 io[i].count = 0; 278 } 279 280 error_bits = -1; 281 dm_io(&io_req, ms->nr_mirrors, io, &error_bits, IOPRIO_DEFAULT); 282 if (unlikely(error_bits != 0)) { 283 for (i = 0; i < ms->nr_mirrors; i++) 284 if (test_bit(i, &error_bits)) 285 fail_mirror(ms->mirror + i, 286 DM_RAID1_FLUSH_ERROR); 287 return -EIO; 288 } 289 290 return 0; 291} 292 293/* 294 *--------------------------------------------------------------- 295 * Recovery. 296 * 297 * When a mirror is first activated we may find that some regions 298 * are in the no-sync state. We have to recover these by 299 * recopying from the default mirror to all the others. 300 *--------------------------------------------------------------- 301 */ 302static void recovery_complete(int read_err, unsigned long write_err, 303 void *context) 304{ 305 struct dm_region *reg = context; 306 struct mirror_set *ms = dm_rh_region_context(reg); 307 int m, bit = 0; 308 309 if (read_err) { 310 /* Read error means the failure of default mirror. */ 311 DMERR_LIMIT("Unable to read primary mirror during recovery"); 312 fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR); 313 } 314 315 if (write_err) { 316 DMERR_LIMIT("Write error during recovery (error = 0x%lx)", 317 write_err); 318 /* 319 * Bits correspond to devices (excluding default mirror). 320 * The default mirror cannot change during recovery. 321 */ 322 for (m = 0; m < ms->nr_mirrors; m++) { 323 if (&ms->mirror[m] == get_default_mirror(ms)) 324 continue; 325 if (test_bit(bit, &write_err)) 326 fail_mirror(ms->mirror + m, 327 DM_RAID1_SYNC_ERROR); 328 bit++; 329 } 330 } 331 332 dm_rh_recovery_end(reg, !(read_err || write_err)); 333} 334 335static void recover(struct mirror_set *ms, struct dm_region *reg) 336{ 337 unsigned int i; 338 struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest; 339 struct mirror *m; 340 unsigned long flags = 0; 341 region_t key = dm_rh_get_region_key(reg); 342 sector_t region_size = dm_rh_get_region_size(ms->rh); 343 344 /* fill in the source */ 345 m = get_default_mirror(ms); 346 from.bdev = m->dev->bdev; 347 from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key); 348 if (key == (ms->nr_regions - 1)) { 349 /* 350 * The final region may be smaller than 351 * region_size. 352 */ 353 from.count = ms->ti->len & (region_size - 1); 354 if (!from.count) 355 from.count = region_size; 356 } else 357 from.count = region_size; 358 359 /* fill in the destinations */ 360 for (i = 0, dest = to; i < ms->nr_mirrors; i++) { 361 if (&ms->mirror[i] == get_default_mirror(ms)) 362 continue; 363 364 m = ms->mirror + i; 365 dest->bdev = m->dev->bdev; 366 dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key); 367 dest->count = from.count; 368 dest++; 369 } 370 371 /* hand to kcopyd */ 372 if (!errors_handled(ms)) 373 flags |= BIT(DM_KCOPYD_IGNORE_ERROR); 374 375 dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to, 376 flags, recovery_complete, reg); 377} 378 379static void reset_ms_flags(struct mirror_set *ms) 380{ 381 unsigned int m; 382 383 ms->leg_failure = 0; 384 for (m = 0; m < ms->nr_mirrors; m++) { 385 atomic_set(&(ms->mirror[m].error_count), 0); 386 ms->mirror[m].error_type = 0; 387 } 388} 389 390static void do_recovery(struct mirror_set *ms) 391{ 392 struct dm_region *reg; 393 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 394 395 /* 396 * Start quiescing some regions. 397 */ 398 dm_rh_recovery_prepare(ms->rh); 399 400 /* 401 * Copy any already quiesced regions. 402 */ 403 while ((reg = dm_rh_recovery_start(ms->rh))) 404 recover(ms, reg); 405 406 /* 407 * Update the in sync flag. 408 */ 409 if (!ms->in_sync && 410 (log->type->get_sync_count(log) == ms->nr_regions)) { 411 /* the sync is complete */ 412 dm_table_event(ms->ti->table); 413 ms->in_sync = 1; 414 reset_ms_flags(ms); 415 } 416} 417 418/* 419 *--------------------------------------------------------------- 420 * Reads 421 *--------------------------------------------------------------- 422 */ 423static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector) 424{ 425 struct mirror *m = get_default_mirror(ms); 426 427 do { 428 if (likely(!atomic_read(&m->error_count))) 429 return m; 430 431 if (m-- == ms->mirror) 432 m += ms->nr_mirrors; 433 } while (m != get_default_mirror(ms)); 434 435 return NULL; 436} 437 438static int default_ok(struct mirror *m) 439{ 440 struct mirror *default_mirror = get_default_mirror(m->ms); 441 442 return !atomic_read(&default_mirror->error_count); 443} 444 445static int mirror_available(struct mirror_set *ms, struct bio *bio) 446{ 447 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 448 region_t region = dm_rh_bio_to_region(ms->rh, bio); 449 450 if (log->type->in_sync(log, region, 0)) 451 return choose_mirror(ms, bio->bi_iter.bi_sector) ? 1 : 0; 452 453 return 0; 454} 455 456/* 457 * remap a buffer to a particular mirror. 458 */ 459static sector_t map_sector(struct mirror *m, struct bio *bio) 460{ 461 if (unlikely(!bio->bi_iter.bi_size)) 462 return 0; 463 return m->offset + dm_target_offset(m->ms->ti, bio->bi_iter.bi_sector); 464} 465 466static void map_bio(struct mirror *m, struct bio *bio) 467{ 468 bio_set_dev(bio, m->dev->bdev); 469 bio->bi_iter.bi_sector = map_sector(m, bio); 470} 471 472static void map_region(struct dm_io_region *io, struct mirror *m, 473 struct bio *bio) 474{ 475 io->bdev = m->dev->bdev; 476 io->sector = map_sector(m, bio); 477 io->count = bio_sectors(bio); 478} 479 480static void hold_bio(struct mirror_set *ms, struct bio *bio) 481{ 482 /* 483 * Lock is required to avoid race condition during suspend 484 * process. 485 */ 486 spin_lock_irq(&ms->lock); 487 488 if (atomic_read(&ms->suspend)) { 489 spin_unlock_irq(&ms->lock); 490 491 /* 492 * If device is suspended, complete the bio. 493 */ 494 if (dm_noflush_suspending(ms->ti)) 495 bio->bi_status = BLK_STS_DM_REQUEUE; 496 else 497 bio->bi_status = BLK_STS_IOERR; 498 499 bio_endio(bio); 500 return; 501 } 502 503 /* 504 * Hold bio until the suspend is complete. 505 */ 506 bio_list_add(&ms->holds, bio); 507 spin_unlock_irq(&ms->lock); 508} 509 510/* 511 *--------------------------------------------------------------- 512 * Reads 513 *--------------------------------------------------------------- 514 */ 515static void read_callback(unsigned long error, void *context) 516{ 517 struct bio *bio = context; 518 struct mirror *m; 519 520 m = bio_get_m(bio); 521 bio_set_m(bio, NULL); 522 523 if (likely(!error)) { 524 bio_endio(bio); 525 return; 526 } 527 528 fail_mirror(m, DM_RAID1_READ_ERROR); 529 530 if (likely(default_ok(m)) || mirror_available(m->ms, bio)) { 531 DMWARN_LIMIT("Read failure on mirror device %s. Trying alternative device.", 532 m->dev->name); 533 queue_bio(m->ms, bio, bio_data_dir(bio)); 534 return; 535 } 536 537 DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.", 538 m->dev->name); 539 bio_io_error(bio); 540} 541 542/* Asynchronous read. */ 543static void read_async_bio(struct mirror *m, struct bio *bio) 544{ 545 struct dm_io_region io; 546 struct dm_io_request io_req = { 547 .bi_opf = REQ_OP_READ, 548 .mem.type = DM_IO_BIO, 549 .mem.ptr.bio = bio, 550 .notify.fn = read_callback, 551 .notify.context = bio, 552 .client = m->ms->io_client, 553 }; 554 555 map_region(&io, m, bio); 556 bio_set_m(bio, m); 557 BUG_ON(dm_io(&io_req, 1, &io, NULL, IOPRIO_DEFAULT)); 558} 559 560static inline int region_in_sync(struct mirror_set *ms, region_t region, 561 int may_block) 562{ 563 int state = dm_rh_get_state(ms->rh, region, may_block); 564 return state == DM_RH_CLEAN || state == DM_RH_DIRTY; 565} 566 567static void do_reads(struct mirror_set *ms, struct bio_list *reads) 568{ 569 region_t region; 570 struct bio *bio; 571 struct mirror *m; 572 573 while ((bio = bio_list_pop(reads))) { 574 region = dm_rh_bio_to_region(ms->rh, bio); 575 m = get_default_mirror(ms); 576 577 /* 578 * We can only read balance if the region is in sync. 579 */ 580 if (likely(region_in_sync(ms, region, 1))) 581 m = choose_mirror(ms, bio->bi_iter.bi_sector); 582 else if (m && atomic_read(&m->error_count)) 583 m = NULL; 584 585 if (likely(m)) 586 read_async_bio(m, bio); 587 else 588 bio_io_error(bio); 589 } 590} 591 592/* 593 *--------------------------------------------------------------------- 594 * Writes. 595 * 596 * We do different things with the write io depending on the 597 * state of the region that it's in: 598 * 599 * SYNC: increment pending, use kcopyd to write to *all* mirrors 600 * RECOVERING: delay the io until recovery completes 601 * NOSYNC: increment pending, just write to the default mirror 602 *--------------------------------------------------------------------- 603 */ 604static void write_callback(unsigned long error, void *context) 605{ 606 unsigned int i; 607 struct bio *bio = context; 608 struct mirror_set *ms; 609 int should_wake = 0; 610 unsigned long flags; 611 612 ms = bio_get_m(bio)->ms; 613 bio_set_m(bio, NULL); 614 615 /* 616 * NOTE: We don't decrement the pending count here, 617 * instead it is done by the targets endio function. 618 * This way we handle both writes to SYNC and NOSYNC 619 * regions with the same code. 620 */ 621 if (likely(!error)) { 622 bio_endio(bio); 623 return; 624 } 625 626 /* 627 * If the bio is discard, return an error, but do not 628 * degrade the array. 629 */ 630 if (bio_op(bio) == REQ_OP_DISCARD) { 631 bio->bi_status = BLK_STS_NOTSUPP; 632 bio_endio(bio); 633 return; 634 } 635 636 for (i = 0; i < ms->nr_mirrors; i++) 637 if (test_bit(i, &error)) 638 fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR); 639 640 /* 641 * Need to raise event. Since raising 642 * events can block, we need to do it in 643 * the main thread. 644 */ 645 spin_lock_irqsave(&ms->lock, flags); 646 if (!ms->failures.head) 647 should_wake = 1; 648 bio_list_add(&ms->failures, bio); 649 spin_unlock_irqrestore(&ms->lock, flags); 650 if (should_wake) 651 wakeup_mirrord(ms); 652} 653 654static void do_write(struct mirror_set *ms, struct bio *bio) 655{ 656 unsigned int i; 657 struct dm_io_region io[MAX_NR_MIRRORS], *dest = io; 658 struct mirror *m; 659 blk_opf_t op_flags = bio->bi_opf & (REQ_FUA | REQ_PREFLUSH); 660 struct dm_io_request io_req = { 661 .bi_opf = REQ_OP_WRITE | op_flags, 662 .mem.type = DM_IO_BIO, 663 .mem.ptr.bio = bio, 664 .notify.fn = write_callback, 665 .notify.context = bio, 666 .client = ms->io_client, 667 }; 668 669 if (bio_op(bio) == REQ_OP_DISCARD) { 670 io_req.bi_opf = REQ_OP_DISCARD | op_flags; 671 io_req.mem.type = DM_IO_KMEM; 672 io_req.mem.ptr.addr = NULL; 673 } 674 675 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) 676 map_region(dest++, m, bio); 677 678 /* 679 * Use default mirror because we only need it to retrieve the reference 680 * to the mirror set in write_callback(). 681 */ 682 bio_set_m(bio, get_default_mirror(ms)); 683 684 BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL, IOPRIO_DEFAULT)); 685} 686 687static void do_writes(struct mirror_set *ms, struct bio_list *writes) 688{ 689 int state; 690 struct bio *bio; 691 struct bio_list sync, nosync, recover, *this_list = NULL; 692 struct bio_list requeue; 693 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 694 region_t region; 695 696 if (!writes->head) 697 return; 698 699 /* 700 * Classify each write. 701 */ 702 bio_list_init(&sync); 703 bio_list_init(&nosync); 704 bio_list_init(&recover); 705 bio_list_init(&requeue); 706 707 while ((bio = bio_list_pop(writes))) { 708 if ((bio->bi_opf & REQ_PREFLUSH) || 709 (bio_op(bio) == REQ_OP_DISCARD)) { 710 bio_list_add(&sync, bio); 711 continue; 712 } 713 714 region = dm_rh_bio_to_region(ms->rh, bio); 715 716 if (log->type->is_remote_recovering && 717 log->type->is_remote_recovering(log, region)) { 718 bio_list_add(&requeue, bio); 719 continue; 720 } 721 722 state = dm_rh_get_state(ms->rh, region, 1); 723 switch (state) { 724 case DM_RH_CLEAN: 725 case DM_RH_DIRTY: 726 this_list = &sync; 727 break; 728 729 case DM_RH_NOSYNC: 730 this_list = &nosync; 731 break; 732 733 case DM_RH_RECOVERING: 734 this_list = &recover; 735 break; 736 } 737 738 bio_list_add(this_list, bio); 739 } 740 741 /* 742 * Add bios that are delayed due to remote recovery 743 * back on to the write queue 744 */ 745 if (unlikely(requeue.head)) { 746 spin_lock_irq(&ms->lock); 747 bio_list_merge(&ms->writes, &requeue); 748 spin_unlock_irq(&ms->lock); 749 delayed_wake(ms); 750 } 751 752 /* 753 * Increment the pending counts for any regions that will 754 * be written to (writes to recover regions are going to 755 * be delayed). 756 */ 757 dm_rh_inc_pending(ms->rh, &sync); 758 dm_rh_inc_pending(ms->rh, &nosync); 759 760 /* 761 * If the flush fails on a previous call and succeeds here, 762 * we must not reset the log_failure variable. We need 763 * userspace interaction to do that. 764 */ 765 ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure; 766 767 /* 768 * Dispatch io. 769 */ 770 if (unlikely(ms->log_failure) && errors_handled(ms)) { 771 spin_lock_irq(&ms->lock); 772 bio_list_merge(&ms->failures, &sync); 773 spin_unlock_irq(&ms->lock); 774 wakeup_mirrord(ms); 775 } else 776 while ((bio = bio_list_pop(&sync))) 777 do_write(ms, bio); 778 779 while ((bio = bio_list_pop(&recover))) 780 dm_rh_delay(ms->rh, bio); 781 782 while ((bio = bio_list_pop(&nosync))) { 783 if (unlikely(ms->leg_failure) && errors_handled(ms) && !keep_log(ms)) { 784 spin_lock_irq(&ms->lock); 785 bio_list_add(&ms->failures, bio); 786 spin_unlock_irq(&ms->lock); 787 wakeup_mirrord(ms); 788 } else { 789 map_bio(get_default_mirror(ms), bio); 790 submit_bio_noacct(bio); 791 } 792 } 793} 794 795static void do_failures(struct mirror_set *ms, struct bio_list *failures) 796{ 797 struct bio *bio; 798 799 if (likely(!failures->head)) 800 return; 801 802 /* 803 * If the log has failed, unattempted writes are being 804 * put on the holds list. We can't issue those writes 805 * until a log has been marked, so we must store them. 806 * 807 * If a 'noflush' suspend is in progress, we can requeue 808 * the I/O's to the core. This give userspace a chance 809 * to reconfigure the mirror, at which point the core 810 * will reissue the writes. If the 'noflush' flag is 811 * not set, we have no choice but to return errors. 812 * 813 * Some writes on the failures list may have been 814 * submitted before the log failure and represent a 815 * failure to write to one of the devices. It is ok 816 * for us to treat them the same and requeue them 817 * as well. 818 */ 819 while ((bio = bio_list_pop(failures))) { 820 if (!ms->log_failure) { 821 ms->in_sync = 0; 822 dm_rh_mark_nosync(ms->rh, bio); 823 } 824 825 /* 826 * If all the legs are dead, fail the I/O. 827 * If the device has failed and keep_log is enabled, 828 * fail the I/O. 829 * 830 * If we have been told to handle errors, and keep_log 831 * isn't enabled, hold the bio and wait for userspace to 832 * deal with the problem. 833 * 834 * Otherwise pretend that the I/O succeeded. (This would 835 * be wrong if the failed leg returned after reboot and 836 * got replicated back to the good legs.) 837 */ 838 if (unlikely(!get_valid_mirror(ms) || (keep_log(ms) && ms->log_failure))) 839 bio_io_error(bio); 840 else if (errors_handled(ms) && !keep_log(ms)) 841 hold_bio(ms, bio); 842 else 843 bio_endio(bio); 844 } 845} 846 847static void trigger_event(struct work_struct *work) 848{ 849 struct mirror_set *ms = 850 container_of(work, struct mirror_set, trigger_event); 851 852 dm_table_event(ms->ti->table); 853} 854 855/* 856 *--------------------------------------------------------------- 857 * kmirrord 858 *--------------------------------------------------------------- 859 */ 860static void do_mirror(struct work_struct *work) 861{ 862 struct mirror_set *ms = container_of(work, struct mirror_set, 863 kmirrord_work); 864 struct bio_list reads, writes, failures; 865 unsigned long flags; 866 867 spin_lock_irqsave(&ms->lock, flags); 868 reads = ms->reads; 869 writes = ms->writes; 870 failures = ms->failures; 871 bio_list_init(&ms->reads); 872 bio_list_init(&ms->writes); 873 bio_list_init(&ms->failures); 874 spin_unlock_irqrestore(&ms->lock, flags); 875 876 dm_rh_update_states(ms->rh, errors_handled(ms)); 877 do_recovery(ms); 878 do_reads(ms, &reads); 879 do_writes(ms, &writes); 880 do_failures(ms, &failures); 881} 882 883/* 884 *--------------------------------------------------------------- 885 * Target functions 886 *--------------------------------------------------------------- 887 */ 888static struct mirror_set *alloc_context(unsigned int nr_mirrors, 889 uint32_t region_size, 890 struct dm_target *ti, 891 struct dm_dirty_log *dl) 892{ 893 struct mirror_set *ms = 894 kzalloc(struct_size(ms, mirror, nr_mirrors), GFP_KERNEL); 895 896 if (!ms) { 897 ti->error = "Cannot allocate mirror context"; 898 return NULL; 899 } 900 901 spin_lock_init(&ms->lock); 902 bio_list_init(&ms->reads); 903 bio_list_init(&ms->writes); 904 bio_list_init(&ms->failures); 905 bio_list_init(&ms->holds); 906 907 ms->ti = ti; 908 ms->nr_mirrors = nr_mirrors; 909 ms->nr_regions = dm_sector_div_up(ti->len, region_size); 910 ms->in_sync = 0; 911 ms->log_failure = 0; 912 ms->leg_failure = 0; 913 atomic_set(&ms->suspend, 0); 914 atomic_set(&ms->default_mirror, DEFAULT_MIRROR); 915 916 ms->io_client = dm_io_client_create(); 917 if (IS_ERR(ms->io_client)) { 918 ti->error = "Error creating dm_io client"; 919 kfree(ms); 920 return NULL; 921 } 922 923 ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord, 924 wakeup_all_recovery_waiters, 925 ms->ti->begin, MAX_RECOVERY, 926 dl, region_size, ms->nr_regions); 927 if (IS_ERR(ms->rh)) { 928 ti->error = "Error creating dirty region hash"; 929 dm_io_client_destroy(ms->io_client); 930 kfree(ms); 931 return NULL; 932 } 933 934 return ms; 935} 936 937static void free_context(struct mirror_set *ms, struct dm_target *ti, 938 unsigned int m) 939{ 940 while (m--) 941 dm_put_device(ti, ms->mirror[m].dev); 942 943 dm_io_client_destroy(ms->io_client); 944 dm_region_hash_destroy(ms->rh); 945 kfree(ms); 946} 947 948static int get_mirror(struct mirror_set *ms, struct dm_target *ti, 949 unsigned int mirror, char **argv) 950{ 951 unsigned long long offset; 952 char dummy; 953 int ret; 954 955 if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1 || 956 offset != (sector_t)offset) { 957 ti->error = "Invalid offset"; 958 return -EINVAL; 959 } 960 961 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), 962 &ms->mirror[mirror].dev); 963 if (ret) { 964 ti->error = "Device lookup failure"; 965 return ret; 966 } 967 968 ms->mirror[mirror].ms = ms; 969 atomic_set(&(ms->mirror[mirror].error_count), 0); 970 ms->mirror[mirror].error_type = 0; 971 ms->mirror[mirror].offset = offset; 972 973 return 0; 974} 975 976/* 977 * Create dirty log: log_type #log_params <log_params> 978 */ 979static struct dm_dirty_log *create_dirty_log(struct dm_target *ti, 980 unsigned int argc, char **argv, 981 unsigned int *args_used) 982{ 983 unsigned int param_count; 984 struct dm_dirty_log *dl; 985 char dummy; 986 987 if (argc < 2) { 988 ti->error = "Insufficient mirror log arguments"; 989 return NULL; 990 } 991 992 if (sscanf(argv[1], "%u%c", ¶m_count, &dummy) != 1) { 993 ti->error = "Invalid mirror log argument count"; 994 return NULL; 995 } 996 997 *args_used = 2 + param_count; 998 999 if (argc < *args_used) { 1000 ti->error = "Insufficient mirror log arguments"; 1001 return NULL; 1002 } 1003 1004 dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count, 1005 argv + 2); 1006 if (!dl) { 1007 ti->error = "Error creating mirror dirty log"; 1008 return NULL; 1009 } 1010 1011 return dl; 1012} 1013 1014static int parse_features(struct mirror_set *ms, unsigned int argc, char **argv, 1015 unsigned int *args_used) 1016{ 1017 unsigned int num_features; 1018 struct dm_target *ti = ms->ti; 1019 char dummy; 1020 int i; 1021 1022 *args_used = 0; 1023 1024 if (!argc) 1025 return 0; 1026 1027 if (sscanf(argv[0], "%u%c", &num_features, &dummy) != 1) { 1028 ti->error = "Invalid number of features"; 1029 return -EINVAL; 1030 } 1031 1032 argc--; 1033 argv++; 1034 (*args_used)++; 1035 1036 if (num_features > argc) { 1037 ti->error = "Not enough arguments to support feature count"; 1038 return -EINVAL; 1039 } 1040 1041 for (i = 0; i < num_features; i++) { 1042 if (!strcmp("handle_errors", argv[0])) 1043 ms->features |= DM_RAID1_HANDLE_ERRORS; 1044 else if (!strcmp("keep_log", argv[0])) 1045 ms->features |= DM_RAID1_KEEP_LOG; 1046 else { 1047 ti->error = "Unrecognised feature requested"; 1048 return -EINVAL; 1049 } 1050 1051 argc--; 1052 argv++; 1053 (*args_used)++; 1054 } 1055 if (!errors_handled(ms) && keep_log(ms)) { 1056 ti->error = "keep_log feature requires the handle_errors feature"; 1057 return -EINVAL; 1058 } 1059 1060 return 0; 1061} 1062 1063/* 1064 * Construct a mirror mapping: 1065 * 1066 * log_type #log_params <log_params> 1067 * #mirrors [mirror_path offset]{2,} 1068 * [#features <features>] 1069 * 1070 * log_type is "core" or "disk" 1071 * #log_params is between 1 and 3 1072 * 1073 * If present, supported features are "handle_errors" and "keep_log". 1074 */ 1075static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) 1076{ 1077 int r; 1078 unsigned int nr_mirrors, m, args_used; 1079 struct mirror_set *ms; 1080 struct dm_dirty_log *dl; 1081 char dummy; 1082 1083 dl = create_dirty_log(ti, argc, argv, &args_used); 1084 if (!dl) 1085 return -EINVAL; 1086 1087 argv += args_used; 1088 argc -= args_used; 1089 1090 if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 || 1091 nr_mirrors < 2 || nr_mirrors > MAX_NR_MIRRORS) { 1092 ti->error = "Invalid number of mirrors"; 1093 dm_dirty_log_destroy(dl); 1094 return -EINVAL; 1095 } 1096 1097 argv++, argc--; 1098 1099 if (argc < nr_mirrors * 2) { 1100 ti->error = "Too few mirror arguments"; 1101 dm_dirty_log_destroy(dl); 1102 return -EINVAL; 1103 } 1104 1105 ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl); 1106 if (!ms) { 1107 dm_dirty_log_destroy(dl); 1108 return -ENOMEM; 1109 } 1110 1111 /* Get the mirror parameter sets */ 1112 for (m = 0; m < nr_mirrors; m++) { 1113 r = get_mirror(ms, ti, m, argv); 1114 if (r) { 1115 free_context(ms, ti, m); 1116 return r; 1117 } 1118 argv += 2; 1119 argc -= 2; 1120 } 1121 1122 ti->private = ms; 1123 1124 r = dm_set_target_max_io_len(ti, dm_rh_get_region_size(ms->rh)); 1125 if (r) 1126 goto err_free_context; 1127 1128 ti->num_flush_bios = 1; 1129 ti->num_discard_bios = 1; 1130 ti->per_io_data_size = sizeof(struct dm_raid1_bio_record); 1131 1132 ms->kmirrord_wq = alloc_workqueue("kmirrord", WQ_MEM_RECLAIM, 0); 1133 if (!ms->kmirrord_wq) { 1134 DMERR("couldn't start kmirrord"); 1135 r = -ENOMEM; 1136 goto err_free_context; 1137 } 1138 INIT_WORK(&ms->kmirrord_work, do_mirror); 1139 timer_setup(&ms->timer, delayed_wake_fn, 0); 1140 ms->timer_pending = 0; 1141 INIT_WORK(&ms->trigger_event, trigger_event); 1142 1143 r = parse_features(ms, argc, argv, &args_used); 1144 if (r) 1145 goto err_destroy_wq; 1146 1147 argv += args_used; 1148 argc -= args_used; 1149 1150 /* 1151 * Any read-balancing addition depends on the 1152 * DM_RAID1_HANDLE_ERRORS flag being present. 1153 * This is because the decision to balance depends 1154 * on the sync state of a region. If the above 1155 * flag is not present, we ignore errors; and 1156 * the sync state may be inaccurate. 1157 */ 1158 1159 if (argc) { 1160 ti->error = "Too many mirror arguments"; 1161 r = -EINVAL; 1162 goto err_destroy_wq; 1163 } 1164 1165 ms->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle); 1166 if (IS_ERR(ms->kcopyd_client)) { 1167 r = PTR_ERR(ms->kcopyd_client); 1168 goto err_destroy_wq; 1169 } 1170 1171 wakeup_mirrord(ms); 1172 return 0; 1173 1174err_destroy_wq: 1175 destroy_workqueue(ms->kmirrord_wq); 1176err_free_context: 1177 free_context(ms, ti, ms->nr_mirrors); 1178 return r; 1179} 1180 1181static void mirror_dtr(struct dm_target *ti) 1182{ 1183 struct mirror_set *ms = ti->private; 1184 1185 del_timer_sync(&ms->timer); 1186 flush_workqueue(ms->kmirrord_wq); 1187 flush_work(&ms->trigger_event); 1188 dm_kcopyd_client_destroy(ms->kcopyd_client); 1189 destroy_workqueue(ms->kmirrord_wq); 1190 free_context(ms, ti, ms->nr_mirrors); 1191} 1192 1193/* 1194 * Mirror mapping function 1195 */ 1196static int mirror_map(struct dm_target *ti, struct bio *bio) 1197{ 1198 int r, rw = bio_data_dir(bio); 1199 struct mirror *m; 1200 struct mirror_set *ms = ti->private; 1201 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1202 struct dm_raid1_bio_record *bio_record = 1203 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record)); 1204 1205 bio_record->details.bi_bdev = NULL; 1206 1207 if (rw == WRITE) { 1208 /* Save region for mirror_end_io() handler */ 1209 bio_record->write_region = dm_rh_bio_to_region(ms->rh, bio); 1210 queue_bio(ms, bio, rw); 1211 return DM_MAPIO_SUBMITTED; 1212 } 1213 1214 r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0); 1215 if (r < 0 && r != -EWOULDBLOCK) 1216 return DM_MAPIO_KILL; 1217 1218 /* 1219 * If region is not in-sync queue the bio. 1220 */ 1221 if (!r || (r == -EWOULDBLOCK)) { 1222 if (bio->bi_opf & REQ_RAHEAD) 1223 return DM_MAPIO_KILL; 1224 1225 queue_bio(ms, bio, rw); 1226 return DM_MAPIO_SUBMITTED; 1227 } 1228 1229 /* 1230 * The region is in-sync and we can perform reads directly. 1231 * Store enough information so we can retry if it fails. 1232 */ 1233 m = choose_mirror(ms, bio->bi_iter.bi_sector); 1234 if (unlikely(!m)) 1235 return DM_MAPIO_KILL; 1236 1237 dm_bio_record(&bio_record->details, bio); 1238 bio_record->m = m; 1239 1240 map_bio(m, bio); 1241 1242 return DM_MAPIO_REMAPPED; 1243} 1244 1245static int mirror_end_io(struct dm_target *ti, struct bio *bio, 1246 blk_status_t *error) 1247{ 1248 int rw = bio_data_dir(bio); 1249 struct mirror_set *ms = ti->private; 1250 struct mirror *m = NULL; 1251 struct dm_bio_details *bd = NULL; 1252 struct dm_raid1_bio_record *bio_record = 1253 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record)); 1254 1255 /* 1256 * We need to dec pending if this was a write. 1257 */ 1258 if (rw == WRITE) { 1259 if (!(bio->bi_opf & REQ_PREFLUSH) && 1260 bio_op(bio) != REQ_OP_DISCARD) 1261 dm_rh_dec(ms->rh, bio_record->write_region); 1262 return DM_ENDIO_DONE; 1263 } 1264 1265 if (*error == BLK_STS_NOTSUPP) 1266 goto out; 1267 1268 if (bio->bi_opf & REQ_RAHEAD) 1269 goto out; 1270 1271 if (unlikely(*error)) { 1272 if (!bio_record->details.bi_bdev) { 1273 /* 1274 * There wasn't enough memory to record necessary 1275 * information for a retry or there was no other 1276 * mirror in-sync. 1277 */ 1278 DMERR_LIMIT("Mirror read failed."); 1279 return DM_ENDIO_DONE; 1280 } 1281 1282 m = bio_record->m; 1283 1284 DMERR("Mirror read failed from %s. Trying alternative device.", 1285 m->dev->name); 1286 1287 fail_mirror(m, DM_RAID1_READ_ERROR); 1288 1289 /* 1290 * A failed read is requeued for another attempt using an intact 1291 * mirror. 1292 */ 1293 if (default_ok(m) || mirror_available(ms, bio)) { 1294 bd = &bio_record->details; 1295 1296 dm_bio_restore(bd, bio); 1297 bio_record->details.bi_bdev = NULL; 1298 bio->bi_status = 0; 1299 1300 queue_bio(ms, bio, rw); 1301 return DM_ENDIO_INCOMPLETE; 1302 } 1303 DMERR("All replicated volumes dead, failing I/O"); 1304 } 1305 1306out: 1307 bio_record->details.bi_bdev = NULL; 1308 1309 return DM_ENDIO_DONE; 1310} 1311 1312static void mirror_presuspend(struct dm_target *ti) 1313{ 1314 struct mirror_set *ms = ti->private; 1315 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1316 1317 struct bio_list holds; 1318 struct bio *bio; 1319 1320 atomic_set(&ms->suspend, 1); 1321 1322 /* 1323 * Process bios in the hold list to start recovery waiting 1324 * for bios in the hold list. After the process, no bio has 1325 * a chance to be added in the hold list because ms->suspend 1326 * is set. 1327 */ 1328 spin_lock_irq(&ms->lock); 1329 holds = ms->holds; 1330 bio_list_init(&ms->holds); 1331 spin_unlock_irq(&ms->lock); 1332 1333 while ((bio = bio_list_pop(&holds))) 1334 hold_bio(ms, bio); 1335 1336 /* 1337 * We must finish up all the work that we've 1338 * generated (i.e. recovery work). 1339 */ 1340 dm_rh_stop_recovery(ms->rh); 1341 1342 wait_event(_kmirrord_recovery_stopped, 1343 !dm_rh_recovery_in_flight(ms->rh)); 1344 1345 if (log->type->presuspend && log->type->presuspend(log)) 1346 /* FIXME: need better error handling */ 1347 DMWARN("log presuspend failed"); 1348 1349 /* 1350 * Now that recovery is complete/stopped and the 1351 * delayed bios are queued, we need to wait for 1352 * the worker thread to complete. This way, 1353 * we know that all of our I/O has been pushed. 1354 */ 1355 flush_workqueue(ms->kmirrord_wq); 1356} 1357 1358static void mirror_postsuspend(struct dm_target *ti) 1359{ 1360 struct mirror_set *ms = ti->private; 1361 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1362 1363 if (log->type->postsuspend && log->type->postsuspend(log)) 1364 /* FIXME: need better error handling */ 1365 DMWARN("log postsuspend failed"); 1366} 1367 1368static void mirror_resume(struct dm_target *ti) 1369{ 1370 struct mirror_set *ms = ti->private; 1371 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1372 1373 atomic_set(&ms->suspend, 0); 1374 if (log->type->resume && log->type->resume(log)) 1375 /* FIXME: need better error handling */ 1376 DMWARN("log resume failed"); 1377 dm_rh_start_recovery(ms->rh); 1378} 1379 1380/* 1381 * device_status_char 1382 * @m: mirror device/leg we want the status of 1383 * 1384 * We return one character representing the most severe error 1385 * we have encountered. 1386 * A => Alive - No failures 1387 * D => Dead - A write failure occurred leaving mirror out-of-sync 1388 * S => Sync - A sychronization failure occurred, mirror out-of-sync 1389 * R => Read - A read failure occurred, mirror data unaffected 1390 * 1391 * Returns: <char> 1392 */ 1393static char device_status_char(struct mirror *m) 1394{ 1395 if (!atomic_read(&(m->error_count))) 1396 return 'A'; 1397 1398 return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' : 1399 (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' : 1400 (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' : 1401 (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U'; 1402} 1403 1404 1405static void mirror_status(struct dm_target *ti, status_type_t type, 1406 unsigned int status_flags, char *result, unsigned int maxlen) 1407{ 1408 unsigned int m, sz = 0; 1409 int num_feature_args = 0; 1410 struct mirror_set *ms = ti->private; 1411 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1412 char buffer[MAX_NR_MIRRORS + 1]; 1413 1414 switch (type) { 1415 case STATUSTYPE_INFO: 1416 DMEMIT("%d ", ms->nr_mirrors); 1417 for (m = 0; m < ms->nr_mirrors; m++) { 1418 DMEMIT("%s ", ms->mirror[m].dev->name); 1419 buffer[m] = device_status_char(&(ms->mirror[m])); 1420 } 1421 buffer[m] = '\0'; 1422 1423 DMEMIT("%llu/%llu 1 %s ", 1424 (unsigned long long)log->type->get_sync_count(log), 1425 (unsigned long long)ms->nr_regions, buffer); 1426 1427 sz += log->type->status(log, type, result+sz, maxlen-sz); 1428 1429 break; 1430 1431 case STATUSTYPE_TABLE: 1432 sz = log->type->status(log, type, result, maxlen); 1433 1434 DMEMIT("%d", ms->nr_mirrors); 1435 for (m = 0; m < ms->nr_mirrors; m++) 1436 DMEMIT(" %s %llu", ms->mirror[m].dev->name, 1437 (unsigned long long)ms->mirror[m].offset); 1438 1439 num_feature_args += !!errors_handled(ms); 1440 num_feature_args += !!keep_log(ms); 1441 if (num_feature_args) { 1442 DMEMIT(" %d", num_feature_args); 1443 if (errors_handled(ms)) 1444 DMEMIT(" handle_errors"); 1445 if (keep_log(ms)) 1446 DMEMIT(" keep_log"); 1447 } 1448 1449 break; 1450 1451 case STATUSTYPE_IMA: 1452 DMEMIT_TARGET_NAME_VERSION(ti->type); 1453 DMEMIT(",nr_mirrors=%d", ms->nr_mirrors); 1454 for (m = 0; m < ms->nr_mirrors; m++) { 1455 DMEMIT(",mirror_device_%d=%s", m, ms->mirror[m].dev->name); 1456 DMEMIT(",mirror_device_%d_status=%c", 1457 m, device_status_char(&(ms->mirror[m]))); 1458 } 1459 1460 DMEMIT(",handle_errors=%c", errors_handled(ms) ? 'y' : 'n'); 1461 DMEMIT(",keep_log=%c", keep_log(ms) ? 'y' : 'n'); 1462 1463 DMEMIT(",log_type_status="); 1464 sz += log->type->status(log, type, result+sz, maxlen-sz); 1465 DMEMIT(";"); 1466 break; 1467 } 1468} 1469 1470static int mirror_iterate_devices(struct dm_target *ti, 1471 iterate_devices_callout_fn fn, void *data) 1472{ 1473 struct mirror_set *ms = ti->private; 1474 int ret = 0; 1475 unsigned int i; 1476 1477 for (i = 0; !ret && i < ms->nr_mirrors; i++) 1478 ret = fn(ti, ms->mirror[i].dev, 1479 ms->mirror[i].offset, ti->len, data); 1480 1481 return ret; 1482} 1483 1484static struct target_type mirror_target = { 1485 .name = "mirror", 1486 .version = {1, 14, 0}, 1487 .module = THIS_MODULE, 1488 .ctr = mirror_ctr, 1489 .dtr = mirror_dtr, 1490 .map = mirror_map, 1491 .end_io = mirror_end_io, 1492 .presuspend = mirror_presuspend, 1493 .postsuspend = mirror_postsuspend, 1494 .resume = mirror_resume, 1495 .status = mirror_status, 1496 .iterate_devices = mirror_iterate_devices, 1497}; 1498 1499static int __init dm_mirror_init(void) 1500{ 1501 int r; 1502 1503 dm_raid1_wq = alloc_workqueue("dm_raid1_wq", 0, 0); 1504 if (!dm_raid1_wq) { 1505 DMERR("Failed to alloc workqueue"); 1506 return -ENOMEM; 1507 } 1508 1509 r = dm_register_target(&mirror_target); 1510 if (r < 0) { 1511 destroy_workqueue(dm_raid1_wq); 1512 return r; 1513 } 1514 1515 return 0; 1516} 1517 1518static void __exit dm_mirror_exit(void) 1519{ 1520 destroy_workqueue(dm_raid1_wq); 1521 dm_unregister_target(&mirror_target); 1522} 1523 1524/* Module hooks */ 1525module_init(dm_mirror_init); 1526module_exit(dm_mirror_exit); 1527 1528MODULE_DESCRIPTION(DM_NAME " mirror target"); 1529MODULE_AUTHOR("Joe Thornber"); 1530MODULE_LICENSE("GPL"); 1531