1 /* 2 * Copyright (C) 2003 Sistina Software Limited. 3 * 4 * This file is released under the GPL. 5 */ 6 7 #include "dm.h" 8 #include "dm-bio-list.h" 9 #include "dm-io.h" 10 #include "dm-log.h" 11 #include "kcopyd.h" 12 13 #include <linux/ctype.h> 14 #include <linux/init.h> 15 #include <linux/mempool.h> 16 #include <linux/module.h> 17 #include <linux/pagemap.h> 18 #include <linux/slab.h> 19 #include <linux/time.h> 20 #include <linux/vmalloc.h> 21 #include <linux/workqueue.h> 22 23 #define DM_MSG_PREFIX "raid1" 24 #define DM_IO_PAGES 64 25 26 #define DM_RAID1_HANDLE_ERRORS 0x01 27 28 static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped); 29 30 /*----------------------------------------------------------------- 31 * Region hash 32 * 33 * The mirror splits itself up into discrete regions. Each 34 * region can be in one of three states: clean, dirty, 35 * nosync. There is no need to put clean regions in the hash. 36 * 37 * In addition to being present in the hash table a region _may_ 38 * be present on one of three lists. 39 * 40 * clean_regions: Regions on this list have no io pending to 41 * them, they are in sync, we are no longer interested in them, 42 * they are dull. rh_update_states() will remove them from the 43 * hash table. 44 * 45 * quiesced_regions: These regions have been spun down, ready 46 * for recovery. rh_recovery_start() will remove regions from 47 * this list and hand them to kmirrord, which will schedule the 48 * recovery io with kcopyd. 49 * 50 * recovered_regions: Regions that kcopyd has successfully 51 * recovered. rh_update_states() will now schedule any delayed 52 * io, up the recovery_count, and remove the region from the 53 * hash. 54 * 55 * There are 2 locks: 56 * A rw spin lock 'hash_lock' protects just the hash table, 57 * this is never held in write mode from interrupt context, 58 * which I believe means that we only have to disable irqs when 59 * doing a write lock. 60 * 61 * An ordinary spin lock 'region_lock' that protects the three 62 * lists in the region_hash, with the 'state', 'list' and 63 * 'bhs_delayed' fields of the regions. This is used from irq 64 * context, so all other uses will have to suspend local irqs. 65 *---------------------------------------------------------------*/ 66 struct mirror_set; 67 struct region_hash { 68 struct mirror_set *ms; 69 uint32_t region_size; 70 unsigned region_shift; 71 72 /* holds persistent region state */ 73 struct dirty_log *log; 74 75 /* hash table */ 76 rwlock_t hash_lock; 77 mempool_t *region_pool; 78 unsigned int mask; 79 unsigned int nr_buckets; 80 struct list_head *buckets; 81 82 spinlock_t region_lock; 83 atomic_t recovery_in_flight; 84 struct semaphore recovery_count; 85 struct list_head clean_regions; 86 struct list_head quiesced_regions; 87 struct list_head recovered_regions; 88 }; 89 90 enum { 91 RH_CLEAN, 92 RH_DIRTY, 93 RH_NOSYNC, 94 RH_RECOVERING 95 }; 96 97 struct region { 98 struct region_hash *rh; /* FIXME: can we get rid of this ? */ 99 region_t key; 100 int state; 101 102 struct list_head hash_list; 103 struct list_head list; 104 105 atomic_t pending; 106 struct bio_list delayed_bios; 107 }; 108 109 110 /*----------------------------------------------------------------- 111 * Mirror set structures. 112 *---------------------------------------------------------------*/ 113 struct mirror { 114 atomic_t error_count; 115 struct dm_dev *dev; 116 sector_t offset; 117 }; 118 119 struct mirror_set { 120 struct dm_target *ti; 121 struct list_head list; 122 struct region_hash rh; 123 struct kcopyd_client *kcopyd_client; 124 uint64_t features; 125 126 spinlock_t lock; /* protects the next two lists */ 127 struct bio_list reads; 128 struct bio_list writes; 129 130 struct dm_io_client *io_client; 131 132 /* recovery */ 133 region_t nr_regions; 134 int in_sync; 135 136 struct mirror *default_mirror; /* Default mirror */ 137 138 struct workqueue_struct *kmirrord_wq; 139 struct work_struct kmirrord_work; 140 141 unsigned int nr_mirrors; 142 struct mirror mirror[0]; 143 }; 144 145 /* 146 * Conversion fns 147 */ 148 static inline region_t bio_to_region(struct region_hash *rh, struct bio *bio) 149 { 150 return (bio->bi_sector - rh->ms->ti->begin) >> rh->region_shift; 151 } 152 153 static inline sector_t region_to_sector(struct region_hash *rh, region_t region) 154 { 155 return region << rh->region_shift; 156 } 157 158 static void wake(struct mirror_set *ms) 159 { 160 queue_work(ms->kmirrord_wq, &ms->kmirrord_work); 161 } 162 163 /* FIXME move this */ 164 static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw); 165 166 #define MIN_REGIONS 64 167 #define MAX_RECOVERY 1 168 static int rh_init(struct region_hash *rh, struct mirror_set *ms, 169 struct dirty_log *log, uint32_t region_size, 170 region_t nr_regions) 171 { 172 unsigned int nr_buckets, max_buckets; 173 size_t i; 174 175 /* 176 * Calculate a suitable number of buckets for our hash 177 * table. 178 */ 179 max_buckets = nr_regions >> 6; 180 for (nr_buckets = 128u; nr_buckets < max_buckets; nr_buckets <<= 1) 181 ; 182 nr_buckets >>= 1; 183 184 rh->ms = ms; 185 rh->log = log; 186 rh->region_size = region_size; 187 rh->region_shift = ffs(region_size) - 1; 188 rwlock_init(&rh->hash_lock); 189 rh->mask = nr_buckets - 1; 190 rh->nr_buckets = nr_buckets; 191 192 rh->buckets = vmalloc(nr_buckets * sizeof(*rh->buckets)); 193 if (!rh->buckets) { 194 DMERR("unable to allocate region hash memory"); 195 return -ENOMEM; 196 } 197 198 for (i = 0; i < nr_buckets; i++) 199 INIT_LIST_HEAD(rh->buckets + i); 200 201 spin_lock_init(&rh->region_lock); 202 sema_init(&rh->recovery_count, 0); 203 atomic_set(&rh->recovery_in_flight, 0); 204 INIT_LIST_HEAD(&rh->clean_regions); 205 INIT_LIST_HEAD(&rh->quiesced_regions); 206 INIT_LIST_HEAD(&rh->recovered_regions); 207 208 rh->region_pool = mempool_create_kmalloc_pool(MIN_REGIONS, 209 sizeof(struct region)); 210 if (!rh->region_pool) { 211 vfree(rh->buckets); 212 rh->buckets = NULL; 213 return -ENOMEM; 214 } 215 216 return 0; 217 } 218 219 static void rh_exit(struct region_hash *rh) 220 { 221 unsigned int h; 222 struct region *reg, *nreg; 223 224 BUG_ON(!list_empty(&rh->quiesced_regions)); 225 for (h = 0; h < rh->nr_buckets; h++) { 226 list_for_each_entry_safe(reg, nreg, rh->buckets + h, hash_list) { 227 BUG_ON(atomic_read(®->pending)); 228 mempool_free(reg, rh->region_pool); 229 } 230 } 231 232 if (rh->log) 233 dm_destroy_dirty_log(rh->log); 234 if (rh->region_pool) 235 mempool_destroy(rh->region_pool); 236 vfree(rh->buckets); 237 } 238 239 #define RH_HASH_MULT 2654435387U 240 241 static inline unsigned int rh_hash(struct region_hash *rh, region_t region) 242 { 243 return (unsigned int) ((region * RH_HASH_MULT) >> 12) & rh->mask; 244 } 245 246 static struct region *__rh_lookup(struct region_hash *rh, region_t region) 247 { 248 struct region *reg; 249 250 list_for_each_entry (reg, rh->buckets + rh_hash(rh, region), hash_list) 251 if (reg->key == region) 252 return reg; 253 254 return NULL; 255 } 256 257 static void __rh_insert(struct region_hash *rh, struct region *reg) 258 { 259 unsigned int h = rh_hash(rh, reg->key); 260 list_add(®->hash_list, rh->buckets + h); 261 } 262 263 static struct region *__rh_alloc(struct region_hash *rh, region_t region) 264 { 265 struct region *reg, *nreg; 266 267 read_unlock(&rh->hash_lock); 268 nreg = mempool_alloc(rh->region_pool, GFP_ATOMIC); 269 if (unlikely(!nreg)) 270 nreg = kmalloc(sizeof(struct region), GFP_NOIO); 271 nreg->state = rh->log->type->in_sync(rh->log, region, 1) ? 272 RH_CLEAN : RH_NOSYNC; 273 nreg->rh = rh; 274 nreg->key = region; 275 276 INIT_LIST_HEAD(&nreg->list); 277 278 atomic_set(&nreg->pending, 0); 279 bio_list_init(&nreg->delayed_bios); 280 write_lock_irq(&rh->hash_lock); 281 282 reg = __rh_lookup(rh, region); 283 if (reg) 284 /* we lost the race */ 285 mempool_free(nreg, rh->region_pool); 286 287 else { 288 __rh_insert(rh, nreg); 289 if (nreg->state == RH_CLEAN) { 290 spin_lock(&rh->region_lock); 291 list_add(&nreg->list, &rh->clean_regions); 292 spin_unlock(&rh->region_lock); 293 } 294 reg = nreg; 295 } 296 write_unlock_irq(&rh->hash_lock); 297 read_lock(&rh->hash_lock); 298 299 return reg; 300 } 301 302 static inline struct region *__rh_find(struct region_hash *rh, region_t region) 303 { 304 struct region *reg; 305 306 reg = __rh_lookup(rh, region); 307 if (!reg) 308 reg = __rh_alloc(rh, region); 309 310 return reg; 311 } 312 313 static int rh_state(struct region_hash *rh, region_t region, int may_block) 314 { 315 int r; 316 struct region *reg; 317 318 read_lock(&rh->hash_lock); 319 reg = __rh_lookup(rh, region); 320 read_unlock(&rh->hash_lock); 321 322 if (reg) 323 return reg->state; 324 325 /* 326 * The region wasn't in the hash, so we fall back to the 327 * dirty log. 328 */ 329 r = rh->log->type->in_sync(rh->log, region, may_block); 330 331 /* 332 * Any error from the dirty log (eg. -EWOULDBLOCK) gets 333 * taken as a RH_NOSYNC 334 */ 335 return r == 1 ? RH_CLEAN : RH_NOSYNC; 336 } 337 338 static inline int rh_in_sync(struct region_hash *rh, 339 region_t region, int may_block) 340 { 341 int state = rh_state(rh, region, may_block); 342 return state == RH_CLEAN || state == RH_DIRTY; 343 } 344 345 static void dispatch_bios(struct mirror_set *ms, struct bio_list *bio_list) 346 { 347 struct bio *bio; 348 349 while ((bio = bio_list_pop(bio_list))) { 350 queue_bio(ms, bio, WRITE); 351 } 352 } 353 354 static void complete_resync_work(struct region *reg, int success) 355 { 356 struct region_hash *rh = reg->rh; 357 358 rh->log->type->set_region_sync(rh->log, reg->key, success); 359 dispatch_bios(rh->ms, ®->delayed_bios); 360 if (atomic_dec_and_test(&rh->recovery_in_flight)) 361 wake_up_all(&_kmirrord_recovery_stopped); 362 up(&rh->recovery_count); 363 } 364 365 static void rh_update_states(struct region_hash *rh) 366 { 367 struct region *reg, *next; 368 369 LIST_HEAD(clean); 370 LIST_HEAD(recovered); 371 372 /* 373 * Quickly grab the lists. 374 */ 375 write_lock_irq(&rh->hash_lock); 376 spin_lock(&rh->region_lock); 377 if (!list_empty(&rh->clean_regions)) { 378 list_splice(&rh->clean_regions, &clean); 379 INIT_LIST_HEAD(&rh->clean_regions); 380 381 list_for_each_entry (reg, &clean, list) { 382 rh->log->type->clear_region(rh->log, reg->key); 383 list_del(®->hash_list); 384 } 385 } 386 387 if (!list_empty(&rh->recovered_regions)) { 388 list_splice(&rh->recovered_regions, &recovered); 389 INIT_LIST_HEAD(&rh->recovered_regions); 390 391 list_for_each_entry (reg, &recovered, list) 392 list_del(®->hash_list); 393 } 394 spin_unlock(&rh->region_lock); 395 write_unlock_irq(&rh->hash_lock); 396 397 /* 398 * All the regions on the recovered and clean lists have 399 * now been pulled out of the system, so no need to do 400 * any more locking. 401 */ 402 list_for_each_entry_safe (reg, next, &recovered, list) { 403 rh->log->type->clear_region(rh->log, reg->key); 404 complete_resync_work(reg, 1); 405 mempool_free(reg, rh->region_pool); 406 } 407 408 rh->log->type->flush(rh->log); 409 410 list_for_each_entry_safe (reg, next, &clean, list) 411 mempool_free(reg, rh->region_pool); 412 } 413 414 static void rh_inc(struct region_hash *rh, region_t region) 415 { 416 struct region *reg; 417 418 read_lock(&rh->hash_lock); 419 reg = __rh_find(rh, region); 420 421 spin_lock_irq(&rh->region_lock); 422 atomic_inc(®->pending); 423 424 if (reg->state == RH_CLEAN) { 425 reg->state = RH_DIRTY; 426 list_del_init(®->list); /* take off the clean list */ 427 spin_unlock_irq(&rh->region_lock); 428 429 rh->log->type->mark_region(rh->log, reg->key); 430 } else 431 spin_unlock_irq(&rh->region_lock); 432 433 434 read_unlock(&rh->hash_lock); 435 } 436 437 static void rh_inc_pending(struct region_hash *rh, struct bio_list *bios) 438 { 439 struct bio *bio; 440 441 for (bio = bios->head; bio; bio = bio->bi_next) 442 rh_inc(rh, bio_to_region(rh, bio)); 443 } 444 445 static void rh_dec(struct region_hash *rh, region_t region) 446 { 447 unsigned long flags; 448 struct region *reg; 449 int should_wake = 0; 450 451 read_lock(&rh->hash_lock); 452 reg = __rh_lookup(rh, region); 453 read_unlock(&rh->hash_lock); 454 455 spin_lock_irqsave(&rh->region_lock, flags); 456 if (atomic_dec_and_test(®->pending)) { 457 /* 458 * There is no pending I/O for this region. 459 * We can move the region to corresponding list for next action. 460 * At this point, the region is not yet connected to any list. 461 * 462 * If the state is RH_NOSYNC, the region should be kept off 463 * from clean list. 464 * The hash entry for RH_NOSYNC will remain in memory 465 * until the region is recovered or the map is reloaded. 466 */ 467 468 /* do nothing for RH_NOSYNC */ 469 if (reg->state == RH_RECOVERING) { 470 list_add_tail(®->list, &rh->quiesced_regions); 471 } else if (reg->state == RH_DIRTY) { 472 reg->state = RH_CLEAN; 473 list_add(®->list, &rh->clean_regions); 474 } 475 should_wake = 1; 476 } 477 spin_unlock_irqrestore(&rh->region_lock, flags); 478 479 if (should_wake) 480 wake(rh->ms); 481 } 482 483 /* 484 * Starts quiescing a region in preparation for recovery. 485 */ 486 static int __rh_recovery_prepare(struct region_hash *rh) 487 { 488 int r; 489 struct region *reg; 490 region_t region; 491 492 /* 493 * Ask the dirty log what's next. 494 */ 495 r = rh->log->type->get_resync_work(rh->log, ®ion); 496 if (r <= 0) 497 return r; 498 499 /* 500 * Get this region, and start it quiescing by setting the 501 * recovering flag. 502 */ 503 read_lock(&rh->hash_lock); 504 reg = __rh_find(rh, region); 505 read_unlock(&rh->hash_lock); 506 507 spin_lock_irq(&rh->region_lock); 508 reg->state = RH_RECOVERING; 509 510 /* Already quiesced ? */ 511 if (atomic_read(®->pending)) 512 list_del_init(®->list); 513 else 514 list_move(®->list, &rh->quiesced_regions); 515 516 spin_unlock_irq(&rh->region_lock); 517 518 return 1; 519 } 520 521 static void rh_recovery_prepare(struct region_hash *rh) 522 { 523 /* Extra reference to avoid race with rh_stop_recovery */ 524 atomic_inc(&rh->recovery_in_flight); 525 526 while (!down_trylock(&rh->recovery_count)) { 527 atomic_inc(&rh->recovery_in_flight); 528 if (__rh_recovery_prepare(rh) <= 0) { 529 atomic_dec(&rh->recovery_in_flight); 530 up(&rh->recovery_count); 531 break; 532 } 533 } 534 535 /* Drop the extra reference */ 536 if (atomic_dec_and_test(&rh->recovery_in_flight)) 537 wake_up_all(&_kmirrord_recovery_stopped); 538 } 539 540 /* 541 * Returns any quiesced regions. 542 */ 543 static struct region *rh_recovery_start(struct region_hash *rh) 544 { 545 struct region *reg = NULL; 546 547 spin_lock_irq(&rh->region_lock); 548 if (!list_empty(&rh->quiesced_regions)) { 549 reg = list_entry(rh->quiesced_regions.next, 550 struct region, list); 551 list_del_init(®->list); /* remove from the quiesced list */ 552 } 553 spin_unlock_irq(&rh->region_lock); 554 555 return reg; 556 } 557 558 /* FIXME: success ignored for now */ 559 static void rh_recovery_end(struct region *reg, int success) 560 { 561 struct region_hash *rh = reg->rh; 562 563 spin_lock_irq(&rh->region_lock); 564 list_add(®->list, ®->rh->recovered_regions); 565 spin_unlock_irq(&rh->region_lock); 566 567 wake(rh->ms); 568 } 569 570 static void rh_flush(struct region_hash *rh) 571 { 572 rh->log->type->flush(rh->log); 573 } 574 575 static void rh_delay(struct region_hash *rh, struct bio *bio) 576 { 577 struct region *reg; 578 579 read_lock(&rh->hash_lock); 580 reg = __rh_find(rh, bio_to_region(rh, bio)); 581 bio_list_add(®->delayed_bios, bio); 582 read_unlock(&rh->hash_lock); 583 } 584 585 static void rh_stop_recovery(struct region_hash *rh) 586 { 587 int i; 588 589 /* wait for any recovering regions */ 590 for (i = 0; i < MAX_RECOVERY; i++) 591 down(&rh->recovery_count); 592 } 593 594 static void rh_start_recovery(struct region_hash *rh) 595 { 596 int i; 597 598 for (i = 0; i < MAX_RECOVERY; i++) 599 up(&rh->recovery_count); 600 601 wake(rh->ms); 602 } 603 604 /* 605 * Every mirror should look like this one. 606 */ 607 #define DEFAULT_MIRROR 0 608 609 /* 610 * This is yucky. We squirrel the mirror_set struct away inside 611 * bi_next for write buffers. This is safe since the bh 612 * doesn't get submitted to the lower levels of block layer. 613 */ 614 static struct mirror_set *bio_get_ms(struct bio *bio) 615 { 616 return (struct mirror_set *) bio->bi_next; 617 } 618 619 static void bio_set_ms(struct bio *bio, struct mirror_set *ms) 620 { 621 bio->bi_next = (struct bio *) ms; 622 } 623 624 /*----------------------------------------------------------------- 625 * Recovery. 626 * 627 * When a mirror is first activated we may find that some regions 628 * are in the no-sync state. We have to recover these by 629 * recopying from the default mirror to all the others. 630 *---------------------------------------------------------------*/ 631 static void recovery_complete(int read_err, unsigned int write_err, 632 void *context) 633 { 634 struct region *reg = (struct region *) context; 635 636 /* FIXME: better error handling */ 637 rh_recovery_end(reg, !(read_err || write_err)); 638 } 639 640 static int recover(struct mirror_set *ms, struct region *reg) 641 { 642 int r; 643 unsigned int i; 644 struct io_region from, to[KCOPYD_MAX_REGIONS], *dest; 645 struct mirror *m; 646 unsigned long flags = 0; 647 648 /* fill in the source */ 649 m = ms->default_mirror; 650 from.bdev = m->dev->bdev; 651 from.sector = m->offset + region_to_sector(reg->rh, reg->key); 652 if (reg->key == (ms->nr_regions - 1)) { 653 /* 654 * The final region may be smaller than 655 * region_size. 656 */ 657 from.count = ms->ti->len & (reg->rh->region_size - 1); 658 if (!from.count) 659 from.count = reg->rh->region_size; 660 } else 661 from.count = reg->rh->region_size; 662 663 /* fill in the destinations */ 664 for (i = 0, dest = to; i < ms->nr_mirrors; i++) { 665 if (&ms->mirror[i] == ms->default_mirror) 666 continue; 667 668 m = ms->mirror + i; 669 dest->bdev = m->dev->bdev; 670 dest->sector = m->offset + region_to_sector(reg->rh, reg->key); 671 dest->count = from.count; 672 dest++; 673 } 674 675 /* hand to kcopyd */ 676 set_bit(KCOPYD_IGNORE_ERROR, &flags); 677 r = kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to, flags, 678 recovery_complete, reg); 679 680 return r; 681 } 682 683 static void do_recovery(struct mirror_set *ms) 684 { 685 int r; 686 struct region *reg; 687 struct dirty_log *log = ms->rh.log; 688 689 /* 690 * Start quiescing some regions. 691 */ 692 rh_recovery_prepare(&ms->rh); 693 694 /* 695 * Copy any already quiesced regions. 696 */ 697 while ((reg = rh_recovery_start(&ms->rh))) { 698 r = recover(ms, reg); 699 if (r) 700 rh_recovery_end(reg, 0); 701 } 702 703 /* 704 * Update the in sync flag. 705 */ 706 if (!ms->in_sync && 707 (log->type->get_sync_count(log) == ms->nr_regions)) { 708 /* the sync is complete */ 709 dm_table_event(ms->ti->table); 710 ms->in_sync = 1; 711 } 712 } 713 714 /*----------------------------------------------------------------- 715 * Reads 716 *---------------------------------------------------------------*/ 717 static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector) 718 { 719 /* FIXME: add read balancing */ 720 return ms->default_mirror; 721 } 722 723 /* 724 * remap a buffer to a particular mirror. 725 */ 726 static void map_bio(struct mirror_set *ms, struct mirror *m, struct bio *bio) 727 { 728 bio->bi_bdev = m->dev->bdev; 729 bio->bi_sector = m->offset + (bio->bi_sector - ms->ti->begin); 730 } 731 732 static void do_reads(struct mirror_set *ms, struct bio_list *reads) 733 { 734 region_t region; 735 struct bio *bio; 736 struct mirror *m; 737 738 while ((bio = bio_list_pop(reads))) { 739 region = bio_to_region(&ms->rh, bio); 740 741 /* 742 * We can only read balance if the region is in sync. 743 */ 744 if (rh_in_sync(&ms->rh, region, 1)) 745 m = choose_mirror(ms, bio->bi_sector); 746 else 747 m = ms->default_mirror; 748 749 map_bio(ms, m, bio); 750 generic_make_request(bio); 751 } 752 } 753 754 /*----------------------------------------------------------------- 755 * Writes. 756 * 757 * We do different things with the write io depending on the 758 * state of the region that it's in: 759 * 760 * SYNC: increment pending, use kcopyd to write to *all* mirrors 761 * RECOVERING: delay the io until recovery completes 762 * NOSYNC: increment pending, just write to the default mirror 763 *---------------------------------------------------------------*/ 764 static void write_callback(unsigned long error, void *context) 765 { 766 unsigned int i; 767 int uptodate = 1; 768 struct bio *bio = (struct bio *) context; 769 struct mirror_set *ms; 770 771 ms = bio_get_ms(bio); 772 bio_set_ms(bio, NULL); 773 774 /* 775 * NOTE: We don't decrement the pending count here, 776 * instead it is done by the targets endio function. 777 * This way we handle both writes to SYNC and NOSYNC 778 * regions with the same code. 779 */ 780 781 if (error) { 782 /* 783 * only error the io if all mirrors failed. 784 * FIXME: bogus 785 */ 786 uptodate = 0; 787 for (i = 0; i < ms->nr_mirrors; i++) 788 if (!test_bit(i, &error)) { 789 uptodate = 1; 790 break; 791 } 792 } 793 bio_endio(bio, bio->bi_size, 0); 794 } 795 796 static void do_write(struct mirror_set *ms, struct bio *bio) 797 { 798 unsigned int i; 799 struct io_region io[KCOPYD_MAX_REGIONS+1]; 800 struct mirror *m; 801 struct dm_io_request io_req = { 802 .bi_rw = WRITE, 803 .mem.type = DM_IO_BVEC, 804 .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx, 805 .notify.fn = write_callback, 806 .notify.context = bio, 807 .client = ms->io_client, 808 }; 809 810 for (i = 0; i < ms->nr_mirrors; i++) { 811 m = ms->mirror + i; 812 813 io[i].bdev = m->dev->bdev; 814 io[i].sector = m->offset + (bio->bi_sector - ms->ti->begin); 815 io[i].count = bio->bi_size >> 9; 816 } 817 818 bio_set_ms(bio, ms); 819 820 (void) dm_io(&io_req, ms->nr_mirrors, io, NULL); 821 } 822 823 static void do_writes(struct mirror_set *ms, struct bio_list *writes) 824 { 825 int state; 826 struct bio *bio; 827 struct bio_list sync, nosync, recover, *this_list = NULL; 828 829 if (!writes->head) 830 return; 831 832 /* 833 * Classify each write. 834 */ 835 bio_list_init(&sync); 836 bio_list_init(&nosync); 837 bio_list_init(&recover); 838 839 while ((bio = bio_list_pop(writes))) { 840 state = rh_state(&ms->rh, bio_to_region(&ms->rh, bio), 1); 841 switch (state) { 842 case RH_CLEAN: 843 case RH_DIRTY: 844 this_list = &sync; 845 break; 846 847 case RH_NOSYNC: 848 this_list = &nosync; 849 break; 850 851 case RH_RECOVERING: 852 this_list = &recover; 853 break; 854 } 855 856 bio_list_add(this_list, bio); 857 } 858 859 /* 860 * Increment the pending counts for any regions that will 861 * be written to (writes to recover regions are going to 862 * be delayed). 863 */ 864 rh_inc_pending(&ms->rh, &sync); 865 rh_inc_pending(&ms->rh, &nosync); 866 rh_flush(&ms->rh); 867 868 /* 869 * Dispatch io. 870 */ 871 while ((bio = bio_list_pop(&sync))) 872 do_write(ms, bio); 873 874 while ((bio = bio_list_pop(&recover))) 875 rh_delay(&ms->rh, bio); 876 877 while ((bio = bio_list_pop(&nosync))) { 878 map_bio(ms, ms->default_mirror, bio); 879 generic_make_request(bio); 880 } 881 } 882 883 /*----------------------------------------------------------------- 884 * kmirrord 885 *---------------------------------------------------------------*/ 886 static void do_mirror(struct work_struct *work) 887 { 888 struct mirror_set *ms =container_of(work, struct mirror_set, 889 kmirrord_work); 890 struct bio_list reads, writes; 891 892 spin_lock(&ms->lock); 893 reads = ms->reads; 894 writes = ms->writes; 895 bio_list_init(&ms->reads); 896 bio_list_init(&ms->writes); 897 spin_unlock(&ms->lock); 898 899 rh_update_states(&ms->rh); 900 do_recovery(ms); 901 do_reads(ms, &reads); 902 do_writes(ms, &writes); 903 } 904 905 /*----------------------------------------------------------------- 906 * Target functions 907 *---------------------------------------------------------------*/ 908 static struct mirror_set *alloc_context(unsigned int nr_mirrors, 909 uint32_t region_size, 910 struct dm_target *ti, 911 struct dirty_log *dl) 912 { 913 size_t len; 914 struct mirror_set *ms = NULL; 915 916 if (array_too_big(sizeof(*ms), sizeof(ms->mirror[0]), nr_mirrors)) 917 return NULL; 918 919 len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors); 920 921 ms = kmalloc(len, GFP_KERNEL); 922 if (!ms) { 923 ti->error = "Cannot allocate mirror context"; 924 return NULL; 925 } 926 927 memset(ms, 0, len); 928 spin_lock_init(&ms->lock); 929 930 ms->ti = ti; 931 ms->nr_mirrors = nr_mirrors; 932 ms->nr_regions = dm_sector_div_up(ti->len, region_size); 933 ms->in_sync = 0; 934 ms->default_mirror = &ms->mirror[DEFAULT_MIRROR]; 935 936 ms->io_client = dm_io_client_create(DM_IO_PAGES); 937 if (IS_ERR(ms->io_client)) { 938 ti->error = "Error creating dm_io client"; 939 kfree(ms); 940 return NULL; 941 } 942 943 if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) { 944 ti->error = "Error creating dirty region hash"; 945 kfree(ms); 946 return NULL; 947 } 948 949 return ms; 950 } 951 952 static void free_context(struct mirror_set *ms, struct dm_target *ti, 953 unsigned int m) 954 { 955 while (m--) 956 dm_put_device(ti, ms->mirror[m].dev); 957 958 dm_io_client_destroy(ms->io_client); 959 rh_exit(&ms->rh); 960 kfree(ms); 961 } 962 963 static inline int _check_region_size(struct dm_target *ti, uint32_t size) 964 { 965 return !(size % (PAGE_SIZE >> 9) || (size & (size - 1)) || 966 size > ti->len); 967 } 968 969 static int get_mirror(struct mirror_set *ms, struct dm_target *ti, 970 unsigned int mirror, char **argv) 971 { 972 unsigned long long offset; 973 974 if (sscanf(argv[1], "%llu", &offset) != 1) { 975 ti->error = "Invalid offset"; 976 return -EINVAL; 977 } 978 979 if (dm_get_device(ti, argv[0], offset, ti->len, 980 dm_table_get_mode(ti->table), 981 &ms->mirror[mirror].dev)) { 982 ti->error = "Device lookup failure"; 983 return -ENXIO; 984 } 985 986 ms->mirror[mirror].offset = offset; 987 988 return 0; 989 } 990 991 /* 992 * Create dirty log: log_type #log_params <log_params> 993 */ 994 static struct dirty_log *create_dirty_log(struct dm_target *ti, 995 unsigned int argc, char **argv, 996 unsigned int *args_used) 997 { 998 unsigned int param_count; 999 struct dirty_log *dl; 1000 1001 if (argc < 2) { 1002 ti->error = "Insufficient mirror log arguments"; 1003 return NULL; 1004 } 1005 1006 if (sscanf(argv[1], "%u", ¶m_count) != 1) { 1007 ti->error = "Invalid mirror log argument count"; 1008 return NULL; 1009 } 1010 1011 *args_used = 2 + param_count; 1012 1013 if (argc < *args_used) { 1014 ti->error = "Insufficient mirror log arguments"; 1015 return NULL; 1016 } 1017 1018 dl = dm_create_dirty_log(argv[0], ti, param_count, argv + 2); 1019 if (!dl) { 1020 ti->error = "Error creating mirror dirty log"; 1021 return NULL; 1022 } 1023 1024 if (!_check_region_size(ti, dl->type->get_region_size(dl))) { 1025 ti->error = "Invalid region size"; 1026 dm_destroy_dirty_log(dl); 1027 return NULL; 1028 } 1029 1030 return dl; 1031 } 1032 1033 static int parse_features(struct mirror_set *ms, unsigned argc, char **argv, 1034 unsigned *args_used) 1035 { 1036 unsigned num_features; 1037 struct dm_target *ti = ms->ti; 1038 1039 *args_used = 0; 1040 1041 if (!argc) 1042 return 0; 1043 1044 if (sscanf(argv[0], "%u", &num_features) != 1) { 1045 ti->error = "Invalid number of features"; 1046 return -EINVAL; 1047 } 1048 1049 argc--; 1050 argv++; 1051 (*args_used)++; 1052 1053 if (num_features > argc) { 1054 ti->error = "Not enough arguments to support feature count"; 1055 return -EINVAL; 1056 } 1057 1058 if (!strcmp("handle_errors", argv[0])) 1059 ms->features |= DM_RAID1_HANDLE_ERRORS; 1060 else { 1061 ti->error = "Unrecognised feature requested"; 1062 return -EINVAL; 1063 } 1064 1065 (*args_used)++; 1066 1067 return 0; 1068 } 1069 1070 /* 1071 * Construct a mirror mapping: 1072 * 1073 * log_type #log_params <log_params> 1074 * #mirrors [mirror_path offset]{2,} 1075 * [#features <features>] 1076 * 1077 * log_type is "core" or "disk" 1078 * #log_params is between 1 and 3 1079 * 1080 * If present, features must be "handle_errors". 1081 */ 1082 static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) 1083 { 1084 int r; 1085 unsigned int nr_mirrors, m, args_used; 1086 struct mirror_set *ms; 1087 struct dirty_log *dl; 1088 1089 dl = create_dirty_log(ti, argc, argv, &args_used); 1090 if (!dl) 1091 return -EINVAL; 1092 1093 argv += args_used; 1094 argc -= args_used; 1095 1096 if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 || 1097 nr_mirrors < 2 || nr_mirrors > KCOPYD_MAX_REGIONS + 1) { 1098 ti->error = "Invalid number of mirrors"; 1099 dm_destroy_dirty_log(dl); 1100 return -EINVAL; 1101 } 1102 1103 argv++, argc--; 1104 1105 if (argc < nr_mirrors * 2) { 1106 ti->error = "Too few mirror arguments"; 1107 dm_destroy_dirty_log(dl); 1108 return -EINVAL; 1109 } 1110 1111 ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl); 1112 if (!ms) { 1113 dm_destroy_dirty_log(dl); 1114 return -ENOMEM; 1115 } 1116 1117 /* Get the mirror parameter sets */ 1118 for (m = 0; m < nr_mirrors; m++) { 1119 r = get_mirror(ms, ti, m, argv); 1120 if (r) { 1121 free_context(ms, ti, m); 1122 return r; 1123 } 1124 argv += 2; 1125 argc -= 2; 1126 } 1127 1128 ti->private = ms; 1129 ti->split_io = ms->rh.region_size; 1130 1131 ms->kmirrord_wq = create_singlethread_workqueue("kmirrord"); 1132 if (!ms->kmirrord_wq) { 1133 DMERR("couldn't start kmirrord"); 1134 free_context(ms, ti, m); 1135 return -ENOMEM; 1136 } 1137 INIT_WORK(&ms->kmirrord_work, do_mirror); 1138 1139 r = parse_features(ms, argc, argv, &args_used); 1140 if (r) { 1141 free_context(ms, ti, ms->nr_mirrors); 1142 return r; 1143 } 1144 1145 argv += args_used; 1146 argc -= args_used; 1147 1148 if (argc) { 1149 ti->error = "Too many mirror arguments"; 1150 free_context(ms, ti, ms->nr_mirrors); 1151 return -EINVAL; 1152 } 1153 1154 r = kcopyd_client_create(DM_IO_PAGES, &ms->kcopyd_client); 1155 if (r) { 1156 destroy_workqueue(ms->kmirrord_wq); 1157 free_context(ms, ti, ms->nr_mirrors); 1158 return r; 1159 } 1160 1161 wake(ms); 1162 return 0; 1163 } 1164 1165 static void mirror_dtr(struct dm_target *ti) 1166 { 1167 struct mirror_set *ms = (struct mirror_set *) ti->private; 1168 1169 flush_workqueue(ms->kmirrord_wq); 1170 kcopyd_client_destroy(ms->kcopyd_client); 1171 destroy_workqueue(ms->kmirrord_wq); 1172 free_context(ms, ti, ms->nr_mirrors); 1173 } 1174 1175 static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw) 1176 { 1177 int should_wake = 0; 1178 struct bio_list *bl; 1179 1180 bl = (rw == WRITE) ? &ms->writes : &ms->reads; 1181 spin_lock(&ms->lock); 1182 should_wake = !(bl->head); 1183 bio_list_add(bl, bio); 1184 spin_unlock(&ms->lock); 1185 1186 if (should_wake) 1187 wake(ms); 1188 } 1189 1190 /* 1191 * Mirror mapping function 1192 */ 1193 static int mirror_map(struct dm_target *ti, struct bio *bio, 1194 union map_info *map_context) 1195 { 1196 int r, rw = bio_rw(bio); 1197 struct mirror *m; 1198 struct mirror_set *ms = ti->private; 1199 1200 map_context->ll = bio_to_region(&ms->rh, bio); 1201 1202 if (rw == WRITE) { 1203 queue_bio(ms, bio, rw); 1204 return DM_MAPIO_SUBMITTED; 1205 } 1206 1207 r = ms->rh.log->type->in_sync(ms->rh.log, 1208 bio_to_region(&ms->rh, bio), 0); 1209 if (r < 0 && r != -EWOULDBLOCK) 1210 return r; 1211 1212 if (r == -EWOULDBLOCK) /* FIXME: ugly */ 1213 r = DM_MAPIO_SUBMITTED; 1214 1215 /* 1216 * We don't want to fast track a recovery just for a read 1217 * ahead. So we just let it silently fail. 1218 * FIXME: get rid of this. 1219 */ 1220 if (!r && rw == READA) 1221 return -EIO; 1222 1223 if (!r) { 1224 /* Pass this io over to the daemon */ 1225 queue_bio(ms, bio, rw); 1226 return DM_MAPIO_SUBMITTED; 1227 } 1228 1229 m = choose_mirror(ms, bio->bi_sector); 1230 if (!m) 1231 return -EIO; 1232 1233 map_bio(ms, m, bio); 1234 return DM_MAPIO_REMAPPED; 1235 } 1236 1237 static int mirror_end_io(struct dm_target *ti, struct bio *bio, 1238 int error, union map_info *map_context) 1239 { 1240 int rw = bio_rw(bio); 1241 struct mirror_set *ms = (struct mirror_set *) ti->private; 1242 region_t region = map_context->ll; 1243 1244 /* 1245 * We need to dec pending if this was a write. 1246 */ 1247 if (rw == WRITE) 1248 rh_dec(&ms->rh, region); 1249 1250 return 0; 1251 } 1252 1253 static void mirror_postsuspend(struct dm_target *ti) 1254 { 1255 struct mirror_set *ms = (struct mirror_set *) ti->private; 1256 struct dirty_log *log = ms->rh.log; 1257 1258 rh_stop_recovery(&ms->rh); 1259 1260 /* Wait for all I/O we generated to complete */ 1261 wait_event(_kmirrord_recovery_stopped, 1262 !atomic_read(&ms->rh.recovery_in_flight)); 1263 1264 if (log->type->suspend && log->type->suspend(log)) 1265 /* FIXME: need better error handling */ 1266 DMWARN("log suspend failed"); 1267 } 1268 1269 static void mirror_resume(struct dm_target *ti) 1270 { 1271 struct mirror_set *ms = (struct mirror_set *) ti->private; 1272 struct dirty_log *log = ms->rh.log; 1273 if (log->type->resume && log->type->resume(log)) 1274 /* FIXME: need better error handling */ 1275 DMWARN("log resume failed"); 1276 rh_start_recovery(&ms->rh); 1277 } 1278 1279 static int mirror_status(struct dm_target *ti, status_type_t type, 1280 char *result, unsigned int maxlen) 1281 { 1282 unsigned int m, sz = 0; 1283 struct mirror_set *ms = (struct mirror_set *) ti->private; 1284 1285 switch (type) { 1286 case STATUSTYPE_INFO: 1287 DMEMIT("%d ", ms->nr_mirrors); 1288 for (m = 0; m < ms->nr_mirrors; m++) 1289 DMEMIT("%s ", ms->mirror[m].dev->name); 1290 1291 DMEMIT("%llu/%llu", 1292 (unsigned long long)ms->rh.log->type-> 1293 get_sync_count(ms->rh.log), 1294 (unsigned long long)ms->nr_regions); 1295 1296 sz = ms->rh.log->type->status(ms->rh.log, type, result, maxlen); 1297 1298 break; 1299 1300 case STATUSTYPE_TABLE: 1301 sz = ms->rh.log->type->status(ms->rh.log, type, result, maxlen); 1302 1303 DMEMIT("%d", ms->nr_mirrors); 1304 for (m = 0; m < ms->nr_mirrors; m++) 1305 DMEMIT(" %s %llu", ms->mirror[m].dev->name, 1306 (unsigned long long)ms->mirror[m].offset); 1307 1308 if (ms->features & DM_RAID1_HANDLE_ERRORS) 1309 DMEMIT(" 1 handle_errors"); 1310 } 1311 1312 return 0; 1313 } 1314 1315 static struct target_type mirror_target = { 1316 .name = "mirror", 1317 .version = {1, 0, 3}, 1318 .module = THIS_MODULE, 1319 .ctr = mirror_ctr, 1320 .dtr = mirror_dtr, 1321 .map = mirror_map, 1322 .end_io = mirror_end_io, 1323 .postsuspend = mirror_postsuspend, 1324 .resume = mirror_resume, 1325 .status = mirror_status, 1326 }; 1327 1328 static int __init dm_mirror_init(void) 1329 { 1330 int r; 1331 1332 r = dm_dirty_log_init(); 1333 if (r) 1334 return r; 1335 1336 r = dm_register_target(&mirror_target); 1337 if (r < 0) { 1338 DMERR("%s: Failed to register mirror target", 1339 mirror_target.name); 1340 dm_dirty_log_exit(); 1341 } 1342 1343 return r; 1344 } 1345 1346 static void __exit dm_mirror_exit(void) 1347 { 1348 int r; 1349 1350 r = dm_unregister_target(&mirror_target); 1351 if (r < 0) 1352 DMERR("%s: unregister failed %d", mirror_target.name, r); 1353 1354 dm_dirty_log_exit(); 1355 } 1356 1357 /* Module hooks */ 1358 module_init(dm_mirror_init); 1359 module_exit(dm_mirror_exit); 1360 1361 MODULE_DESCRIPTION(DM_NAME " mirror target"); 1362 MODULE_AUTHOR("Joe Thornber"); 1363 MODULE_LICENSE("GPL"); 1364