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 #define DM_IO_PAGES 64 26 #define DM_KCOPYD_PAGES 64 27 28 #define DM_RAID1_HANDLE_ERRORS 0x01 29 #define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS) 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_SYNC_ERROR, 39 DM_RAID1_READ_ERROR 40 }; 41 42 struct mirror { 43 struct mirror_set *ms; 44 atomic_t error_count; 45 unsigned long error_type; 46 struct dm_dev *dev; 47 sector_t offset; 48 }; 49 50 struct mirror_set { 51 struct dm_target *ti; 52 struct list_head list; 53 54 uint64_t features; 55 56 spinlock_t lock; /* protects the lists */ 57 struct bio_list reads; 58 struct bio_list writes; 59 struct bio_list failures; 60 61 struct dm_region_hash *rh; 62 struct dm_kcopyd_client *kcopyd_client; 63 struct dm_io_client *io_client; 64 mempool_t *read_record_pool; 65 66 /* recovery */ 67 region_t nr_regions; 68 int in_sync; 69 int log_failure; 70 atomic_t suspend; 71 72 atomic_t default_mirror; /* Default mirror */ 73 74 struct workqueue_struct *kmirrord_wq; 75 struct work_struct kmirrord_work; 76 struct timer_list timer; 77 unsigned long timer_pending; 78 79 struct work_struct trigger_event; 80 81 unsigned nr_mirrors; 82 struct mirror mirror[0]; 83 }; 84 85 static void wakeup_mirrord(void *context) 86 { 87 struct mirror_set *ms = context; 88 89 queue_work(ms->kmirrord_wq, &ms->kmirrord_work); 90 } 91 92 static void delayed_wake_fn(unsigned long data) 93 { 94 struct mirror_set *ms = (struct mirror_set *) data; 95 96 clear_bit(0, &ms->timer_pending); 97 wakeup_mirrord(ms); 98 } 99 100 static void delayed_wake(struct mirror_set *ms) 101 { 102 if (test_and_set_bit(0, &ms->timer_pending)) 103 return; 104 105 ms->timer.expires = jiffies + HZ / 5; 106 ms->timer.data = (unsigned long) ms; 107 ms->timer.function = delayed_wake_fn; 108 add_timer(&ms->timer); 109 } 110 111 static void wakeup_all_recovery_waiters(void *context) 112 { 113 wake_up_all(&_kmirrord_recovery_stopped); 114 } 115 116 static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw) 117 { 118 unsigned long flags; 119 int should_wake = 0; 120 struct bio_list *bl; 121 122 bl = (rw == WRITE) ? &ms->writes : &ms->reads; 123 spin_lock_irqsave(&ms->lock, flags); 124 should_wake = !(bl->head); 125 bio_list_add(bl, bio); 126 spin_unlock_irqrestore(&ms->lock, flags); 127 128 if (should_wake) 129 wakeup_mirrord(ms); 130 } 131 132 static void dispatch_bios(void *context, struct bio_list *bio_list) 133 { 134 struct mirror_set *ms = context; 135 struct bio *bio; 136 137 while ((bio = bio_list_pop(bio_list))) 138 queue_bio(ms, bio, WRITE); 139 } 140 141 #define MIN_READ_RECORDS 20 142 struct dm_raid1_read_record { 143 struct mirror *m; 144 struct dm_bio_details details; 145 }; 146 147 static struct kmem_cache *_dm_raid1_read_record_cache; 148 149 /* 150 * Every mirror should look like this one. 151 */ 152 #define DEFAULT_MIRROR 0 153 154 /* 155 * This is yucky. We squirrel the mirror struct away inside 156 * bi_next for read/write buffers. This is safe since the bh 157 * doesn't get submitted to the lower levels of block layer. 158 */ 159 static struct mirror *bio_get_m(struct bio *bio) 160 { 161 return (struct mirror *) bio->bi_next; 162 } 163 164 static void bio_set_m(struct bio *bio, struct mirror *m) 165 { 166 bio->bi_next = (struct bio *) m; 167 } 168 169 static struct mirror *get_default_mirror(struct mirror_set *ms) 170 { 171 return &ms->mirror[atomic_read(&ms->default_mirror)]; 172 } 173 174 static void set_default_mirror(struct mirror *m) 175 { 176 struct mirror_set *ms = m->ms; 177 struct mirror *m0 = &(ms->mirror[0]); 178 179 atomic_set(&ms->default_mirror, m - m0); 180 } 181 182 /* fail_mirror 183 * @m: mirror device to fail 184 * @error_type: one of the enum's, DM_RAID1_*_ERROR 185 * 186 * If errors are being handled, record the type of 187 * error encountered for this device. If this type 188 * of error has already been recorded, we can return; 189 * otherwise, we must signal userspace by triggering 190 * an event. Additionally, if the device is the 191 * primary device, we must choose a new primary, but 192 * only if the mirror is in-sync. 193 * 194 * This function must not block. 195 */ 196 static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type) 197 { 198 struct mirror_set *ms = m->ms; 199 struct mirror *new; 200 201 /* 202 * error_count is used for nothing more than a 203 * simple way to tell if a device has encountered 204 * errors. 205 */ 206 atomic_inc(&m->error_count); 207 208 if (test_and_set_bit(error_type, &m->error_type)) 209 return; 210 211 if (!errors_handled(ms)) 212 return; 213 214 if (m != get_default_mirror(ms)) 215 goto out; 216 217 if (!ms->in_sync) { 218 /* 219 * Better to issue requests to same failing device 220 * than to risk returning corrupt data. 221 */ 222 DMERR("Primary mirror (%s) failed while out-of-sync: " 223 "Reads may fail.", m->dev->name); 224 goto out; 225 } 226 227 for (new = ms->mirror; new < ms->mirror + ms->nr_mirrors; new++) 228 if (!atomic_read(&new->error_count)) { 229 set_default_mirror(new); 230 break; 231 } 232 233 if (unlikely(new == ms->mirror + ms->nr_mirrors)) 234 DMWARN("All sides of mirror have failed."); 235 236 out: 237 schedule_work(&ms->trigger_event); 238 } 239 240 /*----------------------------------------------------------------- 241 * Recovery. 242 * 243 * When a mirror is first activated we may find that some regions 244 * are in the no-sync state. We have to recover these by 245 * recopying from the default mirror to all the others. 246 *---------------------------------------------------------------*/ 247 static void recovery_complete(int read_err, unsigned long write_err, 248 void *context) 249 { 250 struct dm_region *reg = context; 251 struct mirror_set *ms = dm_rh_region_context(reg); 252 int m, bit = 0; 253 254 if (read_err) { 255 /* Read error means the failure of default mirror. */ 256 DMERR_LIMIT("Unable to read primary mirror during recovery"); 257 fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR); 258 } 259 260 if (write_err) { 261 DMERR_LIMIT("Write error during recovery (error = 0x%lx)", 262 write_err); 263 /* 264 * Bits correspond to devices (excluding default mirror). 265 * The default mirror cannot change during recovery. 266 */ 267 for (m = 0; m < ms->nr_mirrors; m++) { 268 if (&ms->mirror[m] == get_default_mirror(ms)) 269 continue; 270 if (test_bit(bit, &write_err)) 271 fail_mirror(ms->mirror + m, 272 DM_RAID1_SYNC_ERROR); 273 bit++; 274 } 275 } 276 277 dm_rh_recovery_end(reg, !(read_err || write_err)); 278 } 279 280 static int recover(struct mirror_set *ms, struct dm_region *reg) 281 { 282 int r; 283 unsigned i; 284 struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest; 285 struct mirror *m; 286 unsigned long flags = 0; 287 region_t key = dm_rh_get_region_key(reg); 288 sector_t region_size = dm_rh_get_region_size(ms->rh); 289 290 /* fill in the source */ 291 m = get_default_mirror(ms); 292 from.bdev = m->dev->bdev; 293 from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key); 294 if (key == (ms->nr_regions - 1)) { 295 /* 296 * The final region may be smaller than 297 * region_size. 298 */ 299 from.count = ms->ti->len & (region_size - 1); 300 if (!from.count) 301 from.count = region_size; 302 } else 303 from.count = region_size; 304 305 /* fill in the destinations */ 306 for (i = 0, dest = to; i < ms->nr_mirrors; i++) { 307 if (&ms->mirror[i] == get_default_mirror(ms)) 308 continue; 309 310 m = ms->mirror + i; 311 dest->bdev = m->dev->bdev; 312 dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key); 313 dest->count = from.count; 314 dest++; 315 } 316 317 /* hand to kcopyd */ 318 if (!errors_handled(ms)) 319 set_bit(DM_KCOPYD_IGNORE_ERROR, &flags); 320 321 r = dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to, 322 flags, recovery_complete, reg); 323 324 return r; 325 } 326 327 static void do_recovery(struct mirror_set *ms) 328 { 329 struct dm_region *reg; 330 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 331 int r; 332 333 /* 334 * Start quiescing some regions. 335 */ 336 dm_rh_recovery_prepare(ms->rh); 337 338 /* 339 * Copy any already quiesced regions. 340 */ 341 while ((reg = dm_rh_recovery_start(ms->rh))) { 342 r = recover(ms, reg); 343 if (r) 344 dm_rh_recovery_end(reg, 0); 345 } 346 347 /* 348 * Update the in sync flag. 349 */ 350 if (!ms->in_sync && 351 (log->type->get_sync_count(log) == ms->nr_regions)) { 352 /* the sync is complete */ 353 dm_table_event(ms->ti->table); 354 ms->in_sync = 1; 355 } 356 } 357 358 /*----------------------------------------------------------------- 359 * Reads 360 *---------------------------------------------------------------*/ 361 static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector) 362 { 363 struct mirror *m = get_default_mirror(ms); 364 365 do { 366 if (likely(!atomic_read(&m->error_count))) 367 return m; 368 369 if (m-- == ms->mirror) 370 m += ms->nr_mirrors; 371 } while (m != get_default_mirror(ms)); 372 373 return NULL; 374 } 375 376 static int default_ok(struct mirror *m) 377 { 378 struct mirror *default_mirror = get_default_mirror(m->ms); 379 380 return !atomic_read(&default_mirror->error_count); 381 } 382 383 static int mirror_available(struct mirror_set *ms, struct bio *bio) 384 { 385 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 386 region_t region = dm_rh_bio_to_region(ms->rh, bio); 387 388 if (log->type->in_sync(log, region, 0)) 389 return choose_mirror(ms, bio->bi_sector) ? 1 : 0; 390 391 return 0; 392 } 393 394 /* 395 * remap a buffer to a particular mirror. 396 */ 397 static sector_t map_sector(struct mirror *m, struct bio *bio) 398 { 399 return m->offset + (bio->bi_sector - m->ms->ti->begin); 400 } 401 402 static void map_bio(struct mirror *m, struct bio *bio) 403 { 404 bio->bi_bdev = m->dev->bdev; 405 bio->bi_sector = map_sector(m, bio); 406 } 407 408 static void map_region(struct dm_io_region *io, struct mirror *m, 409 struct bio *bio) 410 { 411 io->bdev = m->dev->bdev; 412 io->sector = map_sector(m, bio); 413 io->count = bio->bi_size >> 9; 414 } 415 416 /*----------------------------------------------------------------- 417 * Reads 418 *---------------------------------------------------------------*/ 419 static void read_callback(unsigned long error, void *context) 420 { 421 struct bio *bio = context; 422 struct mirror *m; 423 424 m = bio_get_m(bio); 425 bio_set_m(bio, NULL); 426 427 if (likely(!error)) { 428 bio_endio(bio, 0); 429 return; 430 } 431 432 fail_mirror(m, DM_RAID1_READ_ERROR); 433 434 if (likely(default_ok(m)) || mirror_available(m->ms, bio)) { 435 DMWARN_LIMIT("Read failure on mirror device %s. " 436 "Trying alternative device.", 437 m->dev->name); 438 queue_bio(m->ms, bio, bio_rw(bio)); 439 return; 440 } 441 442 DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.", 443 m->dev->name); 444 bio_endio(bio, -EIO); 445 } 446 447 /* Asynchronous read. */ 448 static void read_async_bio(struct mirror *m, struct bio *bio) 449 { 450 struct dm_io_region io; 451 struct dm_io_request io_req = { 452 .bi_rw = READ, 453 .mem.type = DM_IO_BVEC, 454 .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx, 455 .notify.fn = read_callback, 456 .notify.context = bio, 457 .client = m->ms->io_client, 458 }; 459 460 map_region(&io, m, bio); 461 bio_set_m(bio, m); 462 BUG_ON(dm_io(&io_req, 1, &io, NULL)); 463 } 464 465 static inline int region_in_sync(struct mirror_set *ms, region_t region, 466 int may_block) 467 { 468 int state = dm_rh_get_state(ms->rh, region, may_block); 469 return state == DM_RH_CLEAN || state == DM_RH_DIRTY; 470 } 471 472 static void do_reads(struct mirror_set *ms, struct bio_list *reads) 473 { 474 region_t region; 475 struct bio *bio; 476 struct mirror *m; 477 478 while ((bio = bio_list_pop(reads))) { 479 region = dm_rh_bio_to_region(ms->rh, bio); 480 m = get_default_mirror(ms); 481 482 /* 483 * We can only read balance if the region is in sync. 484 */ 485 if (likely(region_in_sync(ms, region, 1))) 486 m = choose_mirror(ms, bio->bi_sector); 487 else if (m && atomic_read(&m->error_count)) 488 m = NULL; 489 490 if (likely(m)) 491 read_async_bio(m, bio); 492 else 493 bio_endio(bio, -EIO); 494 } 495 } 496 497 /*----------------------------------------------------------------- 498 * Writes. 499 * 500 * We do different things with the write io depending on the 501 * state of the region that it's in: 502 * 503 * SYNC: increment pending, use kcopyd to write to *all* mirrors 504 * RECOVERING: delay the io until recovery completes 505 * NOSYNC: increment pending, just write to the default mirror 506 *---------------------------------------------------------------*/ 507 508 509 static void write_callback(unsigned long error, void *context) 510 { 511 unsigned i, ret = 0; 512 struct bio *bio = (struct bio *) context; 513 struct mirror_set *ms; 514 int uptodate = 0; 515 int should_wake = 0; 516 unsigned long flags; 517 518 ms = bio_get_m(bio)->ms; 519 bio_set_m(bio, NULL); 520 521 /* 522 * NOTE: We don't decrement the pending count here, 523 * instead it is done by the targets endio function. 524 * This way we handle both writes to SYNC and NOSYNC 525 * regions with the same code. 526 */ 527 if (likely(!error)) 528 goto out; 529 530 for (i = 0; i < ms->nr_mirrors; i++) 531 if (test_bit(i, &error)) 532 fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR); 533 else 534 uptodate = 1; 535 536 if (unlikely(!uptodate)) { 537 DMERR("All replicated volumes dead, failing I/O"); 538 /* None of the writes succeeded, fail the I/O. */ 539 ret = -EIO; 540 } else if (errors_handled(ms)) { 541 /* 542 * Need to raise event. Since raising 543 * events can block, we need to do it in 544 * the main thread. 545 */ 546 spin_lock_irqsave(&ms->lock, flags); 547 if (!ms->failures.head) 548 should_wake = 1; 549 bio_list_add(&ms->failures, bio); 550 spin_unlock_irqrestore(&ms->lock, flags); 551 if (should_wake) 552 wakeup_mirrord(ms); 553 return; 554 } 555 out: 556 bio_endio(bio, ret); 557 } 558 559 static void do_write(struct mirror_set *ms, struct bio *bio) 560 { 561 unsigned int i; 562 struct dm_io_region io[ms->nr_mirrors], *dest = io; 563 struct mirror *m; 564 struct dm_io_request io_req = { 565 .bi_rw = WRITE, 566 .mem.type = DM_IO_BVEC, 567 .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx, 568 .notify.fn = write_callback, 569 .notify.context = bio, 570 .client = ms->io_client, 571 }; 572 573 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) 574 map_region(dest++, m, bio); 575 576 /* 577 * Use default mirror because we only need it to retrieve the reference 578 * to the mirror set in write_callback(). 579 */ 580 bio_set_m(bio, get_default_mirror(ms)); 581 582 BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL)); 583 } 584 585 static void do_writes(struct mirror_set *ms, struct bio_list *writes) 586 { 587 int state; 588 struct bio *bio; 589 struct bio_list sync, nosync, recover, *this_list = NULL; 590 struct bio_list requeue; 591 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 592 region_t region; 593 594 if (!writes->head) 595 return; 596 597 /* 598 * Classify each write. 599 */ 600 bio_list_init(&sync); 601 bio_list_init(&nosync); 602 bio_list_init(&recover); 603 bio_list_init(&requeue); 604 605 while ((bio = bio_list_pop(writes))) { 606 region = dm_rh_bio_to_region(ms->rh, bio); 607 608 if (log->type->is_remote_recovering && 609 log->type->is_remote_recovering(log, region)) { 610 bio_list_add(&requeue, bio); 611 continue; 612 } 613 614 state = dm_rh_get_state(ms->rh, region, 1); 615 switch (state) { 616 case DM_RH_CLEAN: 617 case DM_RH_DIRTY: 618 this_list = &sync; 619 break; 620 621 case DM_RH_NOSYNC: 622 this_list = &nosync; 623 break; 624 625 case DM_RH_RECOVERING: 626 this_list = &recover; 627 break; 628 } 629 630 bio_list_add(this_list, bio); 631 } 632 633 /* 634 * Add bios that are delayed due to remote recovery 635 * back on to the write queue 636 */ 637 if (unlikely(requeue.head)) { 638 spin_lock_irq(&ms->lock); 639 bio_list_merge(&ms->writes, &requeue); 640 spin_unlock_irq(&ms->lock); 641 delayed_wake(ms); 642 } 643 644 /* 645 * Increment the pending counts for any regions that will 646 * be written to (writes to recover regions are going to 647 * be delayed). 648 */ 649 dm_rh_inc_pending(ms->rh, &sync); 650 dm_rh_inc_pending(ms->rh, &nosync); 651 652 /* 653 * If the flush fails on a previous call and succeeds here, 654 * we must not reset the log_failure variable. We need 655 * userspace interaction to do that. 656 */ 657 ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure; 658 659 /* 660 * Dispatch io. 661 */ 662 if (unlikely(ms->log_failure)) { 663 spin_lock_irq(&ms->lock); 664 bio_list_merge(&ms->failures, &sync); 665 spin_unlock_irq(&ms->lock); 666 wakeup_mirrord(ms); 667 } else 668 while ((bio = bio_list_pop(&sync))) 669 do_write(ms, bio); 670 671 while ((bio = bio_list_pop(&recover))) 672 dm_rh_delay(ms->rh, bio); 673 674 while ((bio = bio_list_pop(&nosync))) { 675 map_bio(get_default_mirror(ms), bio); 676 generic_make_request(bio); 677 } 678 } 679 680 static void do_failures(struct mirror_set *ms, struct bio_list *failures) 681 { 682 struct bio *bio; 683 684 if (!failures->head) 685 return; 686 687 if (!ms->log_failure) { 688 while ((bio = bio_list_pop(failures))) { 689 ms->in_sync = 0; 690 dm_rh_mark_nosync(ms->rh, bio, bio->bi_size, 0); 691 } 692 return; 693 } 694 695 /* 696 * If the log has failed, unattempted writes are being 697 * put on the failures list. We can't issue those writes 698 * until a log has been marked, so we must store them. 699 * 700 * If a 'noflush' suspend is in progress, we can requeue 701 * the I/O's to the core. This give userspace a chance 702 * to reconfigure the mirror, at which point the core 703 * will reissue the writes. If the 'noflush' flag is 704 * not set, we have no choice but to return errors. 705 * 706 * Some writes on the failures list may have been 707 * submitted before the log failure and represent a 708 * failure to write to one of the devices. It is ok 709 * for us to treat them the same and requeue them 710 * as well. 711 */ 712 if (dm_noflush_suspending(ms->ti)) { 713 while ((bio = bio_list_pop(failures))) 714 bio_endio(bio, DM_ENDIO_REQUEUE); 715 return; 716 } 717 718 if (atomic_read(&ms->suspend)) { 719 while ((bio = bio_list_pop(failures))) 720 bio_endio(bio, -EIO); 721 return; 722 } 723 724 spin_lock_irq(&ms->lock); 725 bio_list_merge(&ms->failures, failures); 726 spin_unlock_irq(&ms->lock); 727 728 delayed_wake(ms); 729 } 730 731 static void trigger_event(struct work_struct *work) 732 { 733 struct mirror_set *ms = 734 container_of(work, struct mirror_set, trigger_event); 735 736 dm_table_event(ms->ti->table); 737 } 738 739 /*----------------------------------------------------------------- 740 * kmirrord 741 *---------------------------------------------------------------*/ 742 static void do_mirror(struct work_struct *work) 743 { 744 struct mirror_set *ms = container_of(work, struct mirror_set, 745 kmirrord_work); 746 struct bio_list reads, writes, failures; 747 unsigned long flags; 748 749 spin_lock_irqsave(&ms->lock, flags); 750 reads = ms->reads; 751 writes = ms->writes; 752 failures = ms->failures; 753 bio_list_init(&ms->reads); 754 bio_list_init(&ms->writes); 755 bio_list_init(&ms->failures); 756 spin_unlock_irqrestore(&ms->lock, flags); 757 758 dm_rh_update_states(ms->rh, errors_handled(ms)); 759 do_recovery(ms); 760 do_reads(ms, &reads); 761 do_writes(ms, &writes); 762 do_failures(ms, &failures); 763 764 dm_table_unplug_all(ms->ti->table); 765 } 766 767 /*----------------------------------------------------------------- 768 * Target functions 769 *---------------------------------------------------------------*/ 770 static struct mirror_set *alloc_context(unsigned int nr_mirrors, 771 uint32_t region_size, 772 struct dm_target *ti, 773 struct dm_dirty_log *dl) 774 { 775 size_t len; 776 struct mirror_set *ms = NULL; 777 778 len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors); 779 780 ms = kzalloc(len, GFP_KERNEL); 781 if (!ms) { 782 ti->error = "Cannot allocate mirror context"; 783 return NULL; 784 } 785 786 spin_lock_init(&ms->lock); 787 788 ms->ti = ti; 789 ms->nr_mirrors = nr_mirrors; 790 ms->nr_regions = dm_sector_div_up(ti->len, region_size); 791 ms->in_sync = 0; 792 ms->log_failure = 0; 793 atomic_set(&ms->suspend, 0); 794 atomic_set(&ms->default_mirror, DEFAULT_MIRROR); 795 796 ms->read_record_pool = mempool_create_slab_pool(MIN_READ_RECORDS, 797 _dm_raid1_read_record_cache); 798 799 if (!ms->read_record_pool) { 800 ti->error = "Error creating mirror read_record_pool"; 801 kfree(ms); 802 return NULL; 803 } 804 805 ms->io_client = dm_io_client_create(DM_IO_PAGES); 806 if (IS_ERR(ms->io_client)) { 807 ti->error = "Error creating dm_io client"; 808 mempool_destroy(ms->read_record_pool); 809 kfree(ms); 810 return NULL; 811 } 812 813 ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord, 814 wakeup_all_recovery_waiters, 815 ms->ti->begin, MAX_RECOVERY, 816 dl, region_size, ms->nr_regions); 817 if (IS_ERR(ms->rh)) { 818 ti->error = "Error creating dirty region hash"; 819 dm_io_client_destroy(ms->io_client); 820 mempool_destroy(ms->read_record_pool); 821 kfree(ms); 822 return NULL; 823 } 824 825 return ms; 826 } 827 828 static void free_context(struct mirror_set *ms, struct dm_target *ti, 829 unsigned int m) 830 { 831 while (m--) 832 dm_put_device(ti, ms->mirror[m].dev); 833 834 dm_io_client_destroy(ms->io_client); 835 dm_region_hash_destroy(ms->rh); 836 mempool_destroy(ms->read_record_pool); 837 kfree(ms); 838 } 839 840 static int get_mirror(struct mirror_set *ms, struct dm_target *ti, 841 unsigned int mirror, char **argv) 842 { 843 unsigned long long offset; 844 845 if (sscanf(argv[1], "%llu", &offset) != 1) { 846 ti->error = "Invalid offset"; 847 return -EINVAL; 848 } 849 850 if (dm_get_device(ti, argv[0], offset, ti->len, 851 dm_table_get_mode(ti->table), 852 &ms->mirror[mirror].dev)) { 853 ti->error = "Device lookup failure"; 854 return -ENXIO; 855 } 856 857 ms->mirror[mirror].ms = ms; 858 atomic_set(&(ms->mirror[mirror].error_count), 0); 859 ms->mirror[mirror].error_type = 0; 860 ms->mirror[mirror].offset = offset; 861 862 return 0; 863 } 864 865 /* 866 * Create dirty log: log_type #log_params <log_params> 867 */ 868 static struct dm_dirty_log *create_dirty_log(struct dm_target *ti, 869 unsigned argc, char **argv, 870 unsigned *args_used) 871 { 872 unsigned param_count; 873 struct dm_dirty_log *dl; 874 875 if (argc < 2) { 876 ti->error = "Insufficient mirror log arguments"; 877 return NULL; 878 } 879 880 if (sscanf(argv[1], "%u", ¶m_count) != 1) { 881 ti->error = "Invalid mirror log argument count"; 882 return NULL; 883 } 884 885 *args_used = 2 + param_count; 886 887 if (argc < *args_used) { 888 ti->error = "Insufficient mirror log arguments"; 889 return NULL; 890 } 891 892 dl = dm_dirty_log_create(argv[0], ti, param_count, argv + 2); 893 if (!dl) { 894 ti->error = "Error creating mirror dirty log"; 895 return NULL; 896 } 897 898 return dl; 899 } 900 901 static int parse_features(struct mirror_set *ms, unsigned argc, char **argv, 902 unsigned *args_used) 903 { 904 unsigned num_features; 905 struct dm_target *ti = ms->ti; 906 907 *args_used = 0; 908 909 if (!argc) 910 return 0; 911 912 if (sscanf(argv[0], "%u", &num_features) != 1) { 913 ti->error = "Invalid number of features"; 914 return -EINVAL; 915 } 916 917 argc--; 918 argv++; 919 (*args_used)++; 920 921 if (num_features > argc) { 922 ti->error = "Not enough arguments to support feature count"; 923 return -EINVAL; 924 } 925 926 if (!strcmp("handle_errors", argv[0])) 927 ms->features |= DM_RAID1_HANDLE_ERRORS; 928 else { 929 ti->error = "Unrecognised feature requested"; 930 return -EINVAL; 931 } 932 933 (*args_used)++; 934 935 return 0; 936 } 937 938 /* 939 * Construct a mirror mapping: 940 * 941 * log_type #log_params <log_params> 942 * #mirrors [mirror_path offset]{2,} 943 * [#features <features>] 944 * 945 * log_type is "core" or "disk" 946 * #log_params is between 1 and 3 947 * 948 * If present, features must be "handle_errors". 949 */ 950 static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) 951 { 952 int r; 953 unsigned int nr_mirrors, m, args_used; 954 struct mirror_set *ms; 955 struct dm_dirty_log *dl; 956 957 dl = create_dirty_log(ti, argc, argv, &args_used); 958 if (!dl) 959 return -EINVAL; 960 961 argv += args_used; 962 argc -= args_used; 963 964 if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 || 965 nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) { 966 ti->error = "Invalid number of mirrors"; 967 dm_dirty_log_destroy(dl); 968 return -EINVAL; 969 } 970 971 argv++, argc--; 972 973 if (argc < nr_mirrors * 2) { 974 ti->error = "Too few mirror arguments"; 975 dm_dirty_log_destroy(dl); 976 return -EINVAL; 977 } 978 979 ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl); 980 if (!ms) { 981 dm_dirty_log_destroy(dl); 982 return -ENOMEM; 983 } 984 985 /* Get the mirror parameter sets */ 986 for (m = 0; m < nr_mirrors; m++) { 987 r = get_mirror(ms, ti, m, argv); 988 if (r) { 989 free_context(ms, ti, m); 990 return r; 991 } 992 argv += 2; 993 argc -= 2; 994 } 995 996 ti->private = ms; 997 ti->split_io = dm_rh_get_region_size(ms->rh); 998 999 ms->kmirrord_wq = create_singlethread_workqueue("kmirrord"); 1000 if (!ms->kmirrord_wq) { 1001 DMERR("couldn't start kmirrord"); 1002 r = -ENOMEM; 1003 goto err_free_context; 1004 } 1005 INIT_WORK(&ms->kmirrord_work, do_mirror); 1006 init_timer(&ms->timer); 1007 ms->timer_pending = 0; 1008 INIT_WORK(&ms->trigger_event, trigger_event); 1009 1010 r = parse_features(ms, argc, argv, &args_used); 1011 if (r) 1012 goto err_destroy_wq; 1013 1014 argv += args_used; 1015 argc -= args_used; 1016 1017 /* 1018 * Any read-balancing addition depends on the 1019 * DM_RAID1_HANDLE_ERRORS flag being present. 1020 * This is because the decision to balance depends 1021 * on the sync state of a region. If the above 1022 * flag is not present, we ignore errors; and 1023 * the sync state may be inaccurate. 1024 */ 1025 1026 if (argc) { 1027 ti->error = "Too many mirror arguments"; 1028 r = -EINVAL; 1029 goto err_destroy_wq; 1030 } 1031 1032 r = dm_kcopyd_client_create(DM_KCOPYD_PAGES, &ms->kcopyd_client); 1033 if (r) 1034 goto err_destroy_wq; 1035 1036 wakeup_mirrord(ms); 1037 return 0; 1038 1039 err_destroy_wq: 1040 destroy_workqueue(ms->kmirrord_wq); 1041 err_free_context: 1042 free_context(ms, ti, ms->nr_mirrors); 1043 return r; 1044 } 1045 1046 static void mirror_dtr(struct dm_target *ti) 1047 { 1048 struct mirror_set *ms = (struct mirror_set *) ti->private; 1049 1050 del_timer_sync(&ms->timer); 1051 flush_workqueue(ms->kmirrord_wq); 1052 flush_scheduled_work(); 1053 dm_kcopyd_client_destroy(ms->kcopyd_client); 1054 destroy_workqueue(ms->kmirrord_wq); 1055 free_context(ms, ti, ms->nr_mirrors); 1056 } 1057 1058 /* 1059 * Mirror mapping function 1060 */ 1061 static int mirror_map(struct dm_target *ti, struct bio *bio, 1062 union map_info *map_context) 1063 { 1064 int r, rw = bio_rw(bio); 1065 struct mirror *m; 1066 struct mirror_set *ms = ti->private; 1067 struct dm_raid1_read_record *read_record = NULL; 1068 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1069 1070 if (rw == WRITE) { 1071 /* Save region for mirror_end_io() handler */ 1072 map_context->ll = dm_rh_bio_to_region(ms->rh, bio); 1073 queue_bio(ms, bio, rw); 1074 return DM_MAPIO_SUBMITTED; 1075 } 1076 1077 r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0); 1078 if (r < 0 && r != -EWOULDBLOCK) 1079 return r; 1080 1081 /* 1082 * If region is not in-sync queue the bio. 1083 */ 1084 if (!r || (r == -EWOULDBLOCK)) { 1085 if (rw == READA) 1086 return -EWOULDBLOCK; 1087 1088 queue_bio(ms, bio, rw); 1089 return DM_MAPIO_SUBMITTED; 1090 } 1091 1092 /* 1093 * The region is in-sync and we can perform reads directly. 1094 * Store enough information so we can retry if it fails. 1095 */ 1096 m = choose_mirror(ms, bio->bi_sector); 1097 if (unlikely(!m)) 1098 return -EIO; 1099 1100 read_record = mempool_alloc(ms->read_record_pool, GFP_NOIO); 1101 if (likely(read_record)) { 1102 dm_bio_record(&read_record->details, bio); 1103 map_context->ptr = read_record; 1104 read_record->m = m; 1105 } 1106 1107 map_bio(m, bio); 1108 1109 return DM_MAPIO_REMAPPED; 1110 } 1111 1112 static int mirror_end_io(struct dm_target *ti, struct bio *bio, 1113 int error, union map_info *map_context) 1114 { 1115 int rw = bio_rw(bio); 1116 struct mirror_set *ms = (struct mirror_set *) ti->private; 1117 struct mirror *m = NULL; 1118 struct dm_bio_details *bd = NULL; 1119 struct dm_raid1_read_record *read_record = map_context->ptr; 1120 1121 /* 1122 * We need to dec pending if this was a write. 1123 */ 1124 if (rw == WRITE) { 1125 dm_rh_dec(ms->rh, map_context->ll); 1126 return error; 1127 } 1128 1129 if (error == -EOPNOTSUPP) 1130 goto out; 1131 1132 if ((error == -EWOULDBLOCK) && bio_rw_flagged(bio, BIO_RW_AHEAD)) 1133 goto out; 1134 1135 if (unlikely(error)) { 1136 if (!read_record) { 1137 /* 1138 * There wasn't enough memory to record necessary 1139 * information for a retry or there was no other 1140 * mirror in-sync. 1141 */ 1142 DMERR_LIMIT("Mirror read failed."); 1143 return -EIO; 1144 } 1145 1146 m = read_record->m; 1147 1148 DMERR("Mirror read failed from %s. Trying alternative device.", 1149 m->dev->name); 1150 1151 fail_mirror(m, DM_RAID1_READ_ERROR); 1152 1153 /* 1154 * A failed read is requeued for another attempt using an intact 1155 * mirror. 1156 */ 1157 if (default_ok(m) || mirror_available(ms, bio)) { 1158 bd = &read_record->details; 1159 1160 dm_bio_restore(bd, bio); 1161 mempool_free(read_record, ms->read_record_pool); 1162 map_context->ptr = NULL; 1163 queue_bio(ms, bio, rw); 1164 return 1; 1165 } 1166 DMERR("All replicated volumes dead, failing I/O"); 1167 } 1168 1169 out: 1170 if (read_record) { 1171 mempool_free(read_record, ms->read_record_pool); 1172 map_context->ptr = NULL; 1173 } 1174 1175 return error; 1176 } 1177 1178 static void mirror_presuspend(struct dm_target *ti) 1179 { 1180 struct mirror_set *ms = (struct mirror_set *) ti->private; 1181 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1182 1183 atomic_set(&ms->suspend, 1); 1184 1185 /* 1186 * We must finish up all the work that we've 1187 * generated (i.e. recovery work). 1188 */ 1189 dm_rh_stop_recovery(ms->rh); 1190 1191 wait_event(_kmirrord_recovery_stopped, 1192 !dm_rh_recovery_in_flight(ms->rh)); 1193 1194 if (log->type->presuspend && log->type->presuspend(log)) 1195 /* FIXME: need better error handling */ 1196 DMWARN("log presuspend failed"); 1197 1198 /* 1199 * Now that recovery is complete/stopped and the 1200 * delayed bios are queued, we need to wait for 1201 * the worker thread to complete. This way, 1202 * we know that all of our I/O has been pushed. 1203 */ 1204 flush_workqueue(ms->kmirrord_wq); 1205 } 1206 1207 static void mirror_postsuspend(struct dm_target *ti) 1208 { 1209 struct mirror_set *ms = ti->private; 1210 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1211 1212 if (log->type->postsuspend && log->type->postsuspend(log)) 1213 /* FIXME: need better error handling */ 1214 DMWARN("log postsuspend failed"); 1215 } 1216 1217 static void mirror_resume(struct dm_target *ti) 1218 { 1219 struct mirror_set *ms = ti->private; 1220 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1221 1222 atomic_set(&ms->suspend, 0); 1223 if (log->type->resume && log->type->resume(log)) 1224 /* FIXME: need better error handling */ 1225 DMWARN("log resume failed"); 1226 dm_rh_start_recovery(ms->rh); 1227 } 1228 1229 /* 1230 * device_status_char 1231 * @m: mirror device/leg we want the status of 1232 * 1233 * We return one character representing the most severe error 1234 * we have encountered. 1235 * A => Alive - No failures 1236 * D => Dead - A write failure occurred leaving mirror out-of-sync 1237 * S => Sync - A sychronization failure occurred, mirror out-of-sync 1238 * R => Read - A read failure occurred, mirror data unaffected 1239 * 1240 * Returns: <char> 1241 */ 1242 static char device_status_char(struct mirror *m) 1243 { 1244 if (!atomic_read(&(m->error_count))) 1245 return 'A'; 1246 1247 return (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' : 1248 (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' : 1249 (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U'; 1250 } 1251 1252 1253 static int mirror_status(struct dm_target *ti, status_type_t type, 1254 char *result, unsigned int maxlen) 1255 { 1256 unsigned int m, sz = 0; 1257 struct mirror_set *ms = (struct mirror_set *) ti->private; 1258 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1259 char buffer[ms->nr_mirrors + 1]; 1260 1261 switch (type) { 1262 case STATUSTYPE_INFO: 1263 DMEMIT("%d ", ms->nr_mirrors); 1264 for (m = 0; m < ms->nr_mirrors; m++) { 1265 DMEMIT("%s ", ms->mirror[m].dev->name); 1266 buffer[m] = device_status_char(&(ms->mirror[m])); 1267 } 1268 buffer[m] = '\0'; 1269 1270 DMEMIT("%llu/%llu 1 %s ", 1271 (unsigned long long)log->type->get_sync_count(log), 1272 (unsigned long long)ms->nr_regions, buffer); 1273 1274 sz += log->type->status(log, type, result+sz, maxlen-sz); 1275 1276 break; 1277 1278 case STATUSTYPE_TABLE: 1279 sz = log->type->status(log, type, result, maxlen); 1280 1281 DMEMIT("%d", ms->nr_mirrors); 1282 for (m = 0; m < ms->nr_mirrors; m++) 1283 DMEMIT(" %s %llu", ms->mirror[m].dev->name, 1284 (unsigned long long)ms->mirror[m].offset); 1285 1286 if (ms->features & DM_RAID1_HANDLE_ERRORS) 1287 DMEMIT(" 1 handle_errors"); 1288 } 1289 1290 return 0; 1291 } 1292 1293 static int mirror_iterate_devices(struct dm_target *ti, 1294 iterate_devices_callout_fn fn, void *data) 1295 { 1296 struct mirror_set *ms = ti->private; 1297 int ret = 0; 1298 unsigned i; 1299 1300 for (i = 0; !ret && i < ms->nr_mirrors; i++) 1301 ret = fn(ti, ms->mirror[i].dev, 1302 ms->mirror[i].offset, ti->len, data); 1303 1304 return ret; 1305 } 1306 1307 static struct target_type mirror_target = { 1308 .name = "mirror", 1309 .version = {1, 12, 0}, 1310 .module = THIS_MODULE, 1311 .ctr = mirror_ctr, 1312 .dtr = mirror_dtr, 1313 .map = mirror_map, 1314 .end_io = mirror_end_io, 1315 .presuspend = mirror_presuspend, 1316 .postsuspend = mirror_postsuspend, 1317 .resume = mirror_resume, 1318 .status = mirror_status, 1319 .iterate_devices = mirror_iterate_devices, 1320 }; 1321 1322 static int __init dm_mirror_init(void) 1323 { 1324 int r; 1325 1326 _dm_raid1_read_record_cache = KMEM_CACHE(dm_raid1_read_record, 0); 1327 if (!_dm_raid1_read_record_cache) { 1328 DMERR("Can't allocate dm_raid1_read_record cache"); 1329 r = -ENOMEM; 1330 goto bad_cache; 1331 } 1332 1333 r = dm_register_target(&mirror_target); 1334 if (r < 0) { 1335 DMERR("Failed to register mirror target"); 1336 goto bad_target; 1337 } 1338 1339 return 0; 1340 1341 bad_target: 1342 kmem_cache_destroy(_dm_raid1_read_record_cache); 1343 bad_cache: 1344 return r; 1345 } 1346 1347 static void __exit dm_mirror_exit(void) 1348 { 1349 dm_unregister_target(&mirror_target); 1350 kmem_cache_destroy(_dm_raid1_read_record_cache); 1351 } 1352 1353 /* Module hooks */ 1354 module_init(dm_mirror_init); 1355 module_exit(dm_mirror_exit); 1356 1357 MODULE_DESCRIPTION(DM_NAME " mirror target"); 1358 MODULE_AUTHOR("Joe Thornber"); 1359 MODULE_LICENSE("GPL"); 1360