1 /* 2 * Copyright (C) 2011-2012 Red Hat UK. 3 * 4 * This file is released under the GPL. 5 */ 6 7 #include "dm-thin-metadata.h" 8 #include "dm-bio-prison.h" 9 #include "dm.h" 10 11 #include <linux/device-mapper.h> 12 #include <linux/dm-io.h> 13 #include <linux/dm-kcopyd.h> 14 #include <linux/jiffies.h> 15 #include <linux/log2.h> 16 #include <linux/list.h> 17 #include <linux/rculist.h> 18 #include <linux/init.h> 19 #include <linux/module.h> 20 #include <linux/slab.h> 21 #include <linux/vmalloc.h> 22 #include <linux/sort.h> 23 #include <linux/rbtree.h> 24 25 #define DM_MSG_PREFIX "thin" 26 27 /* 28 * Tunable constants 29 */ 30 #define ENDIO_HOOK_POOL_SIZE 1024 31 #define MAPPING_POOL_SIZE 1024 32 #define COMMIT_PERIOD HZ 33 #define NO_SPACE_TIMEOUT_SECS 60 34 35 static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS; 36 37 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle, 38 "A percentage of time allocated for copy on write"); 39 40 /* 41 * The block size of the device holding pool data must be 42 * between 64KB and 1GB. 43 */ 44 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT) 45 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) 46 47 /* 48 * Device id is restricted to 24 bits. 49 */ 50 #define MAX_DEV_ID ((1 << 24) - 1) 51 52 /* 53 * How do we handle breaking sharing of data blocks? 54 * ================================================= 55 * 56 * We use a standard copy-on-write btree to store the mappings for the 57 * devices (note I'm talking about copy-on-write of the metadata here, not 58 * the data). When you take an internal snapshot you clone the root node 59 * of the origin btree. After this there is no concept of an origin or a 60 * snapshot. They are just two device trees that happen to point to the 61 * same data blocks. 62 * 63 * When we get a write in we decide if it's to a shared data block using 64 * some timestamp magic. If it is, we have to break sharing. 65 * 66 * Let's say we write to a shared block in what was the origin. The 67 * steps are: 68 * 69 * i) plug io further to this physical block. (see bio_prison code). 70 * 71 * ii) quiesce any read io to that shared data block. Obviously 72 * including all devices that share this block. (see dm_deferred_set code) 73 * 74 * iii) copy the data block to a newly allocate block. This step can be 75 * missed out if the io covers the block. (schedule_copy). 76 * 77 * iv) insert the new mapping into the origin's btree 78 * (process_prepared_mapping). This act of inserting breaks some 79 * sharing of btree nodes between the two devices. Breaking sharing only 80 * effects the btree of that specific device. Btrees for the other 81 * devices that share the block never change. The btree for the origin 82 * device as it was after the last commit is untouched, ie. we're using 83 * persistent data structures in the functional programming sense. 84 * 85 * v) unplug io to this physical block, including the io that triggered 86 * the breaking of sharing. 87 * 88 * Steps (ii) and (iii) occur in parallel. 89 * 90 * The metadata _doesn't_ need to be committed before the io continues. We 91 * get away with this because the io is always written to a _new_ block. 92 * If there's a crash, then: 93 * 94 * - The origin mapping will point to the old origin block (the shared 95 * one). This will contain the data as it was before the io that triggered 96 * the breaking of sharing came in. 97 * 98 * - The snap mapping still points to the old block. As it would after 99 * the commit. 100 * 101 * The downside of this scheme is the timestamp magic isn't perfect, and 102 * will continue to think that data block in the snapshot device is shared 103 * even after the write to the origin has broken sharing. I suspect data 104 * blocks will typically be shared by many different devices, so we're 105 * breaking sharing n + 1 times, rather than n, where n is the number of 106 * devices that reference this data block. At the moment I think the 107 * benefits far, far outweigh the disadvantages. 108 */ 109 110 /*----------------------------------------------------------------*/ 111 112 /* 113 * Key building. 114 */ 115 enum lock_space { 116 VIRTUAL, 117 PHYSICAL 118 }; 119 120 static void build_key(struct dm_thin_device *td, enum lock_space ls, 121 dm_block_t b, dm_block_t e, struct dm_cell_key *key) 122 { 123 key->virtual = (ls == VIRTUAL); 124 key->dev = dm_thin_dev_id(td); 125 key->block_begin = b; 126 key->block_end = e; 127 } 128 129 static void build_data_key(struct dm_thin_device *td, dm_block_t b, 130 struct dm_cell_key *key) 131 { 132 build_key(td, PHYSICAL, b, b + 1llu, key); 133 } 134 135 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b, 136 struct dm_cell_key *key) 137 { 138 build_key(td, VIRTUAL, b, b + 1llu, key); 139 } 140 141 /*----------------------------------------------------------------*/ 142 143 #define THROTTLE_THRESHOLD (1 * HZ) 144 145 struct throttle { 146 struct rw_semaphore lock; 147 unsigned long threshold; 148 bool throttle_applied; 149 }; 150 151 static void throttle_init(struct throttle *t) 152 { 153 init_rwsem(&t->lock); 154 t->throttle_applied = false; 155 } 156 157 static void throttle_work_start(struct throttle *t) 158 { 159 t->threshold = jiffies + THROTTLE_THRESHOLD; 160 } 161 162 static void throttle_work_update(struct throttle *t) 163 { 164 if (!t->throttle_applied && jiffies > t->threshold) { 165 down_write(&t->lock); 166 t->throttle_applied = true; 167 } 168 } 169 170 static void throttle_work_complete(struct throttle *t) 171 { 172 if (t->throttle_applied) { 173 t->throttle_applied = false; 174 up_write(&t->lock); 175 } 176 } 177 178 static void throttle_lock(struct throttle *t) 179 { 180 down_read(&t->lock); 181 } 182 183 static void throttle_unlock(struct throttle *t) 184 { 185 up_read(&t->lock); 186 } 187 188 /*----------------------------------------------------------------*/ 189 190 /* 191 * A pool device ties together a metadata device and a data device. It 192 * also provides the interface for creating and destroying internal 193 * devices. 194 */ 195 struct dm_thin_new_mapping; 196 197 /* 198 * The pool runs in 4 modes. Ordered in degraded order for comparisons. 199 */ 200 enum pool_mode { 201 PM_WRITE, /* metadata may be changed */ 202 PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */ 203 PM_READ_ONLY, /* metadata may not be changed */ 204 PM_FAIL, /* all I/O fails */ 205 }; 206 207 struct pool_features { 208 enum pool_mode mode; 209 210 bool zero_new_blocks:1; 211 bool discard_enabled:1; 212 bool discard_passdown:1; 213 bool error_if_no_space:1; 214 }; 215 216 struct thin_c; 217 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio); 218 typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell); 219 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m); 220 221 #define CELL_SORT_ARRAY_SIZE 8192 222 223 struct pool { 224 struct list_head list; 225 struct dm_target *ti; /* Only set if a pool target is bound */ 226 227 struct mapped_device *pool_md; 228 struct block_device *md_dev; 229 struct dm_pool_metadata *pmd; 230 231 dm_block_t low_water_blocks; 232 uint32_t sectors_per_block; 233 int sectors_per_block_shift; 234 235 struct pool_features pf; 236 bool low_water_triggered:1; /* A dm event has been sent */ 237 bool suspended:1; 238 239 struct dm_bio_prison *prison; 240 struct dm_kcopyd_client *copier; 241 242 struct workqueue_struct *wq; 243 struct throttle throttle; 244 struct work_struct worker; 245 struct delayed_work waker; 246 struct delayed_work no_space_timeout; 247 248 unsigned long last_commit_jiffies; 249 unsigned ref_count; 250 251 spinlock_t lock; 252 struct bio_list deferred_flush_bios; 253 struct list_head prepared_mappings; 254 struct list_head prepared_discards; 255 struct list_head active_thins; 256 257 struct dm_deferred_set *shared_read_ds; 258 struct dm_deferred_set *all_io_ds; 259 260 struct dm_thin_new_mapping *next_mapping; 261 mempool_t *mapping_pool; 262 263 process_bio_fn process_bio; 264 process_bio_fn process_discard; 265 266 process_cell_fn process_cell; 267 process_cell_fn process_discard_cell; 268 269 process_mapping_fn process_prepared_mapping; 270 process_mapping_fn process_prepared_discard; 271 272 struct dm_bio_prison_cell **cell_sort_array; 273 }; 274 275 static enum pool_mode get_pool_mode(struct pool *pool); 276 static void metadata_operation_failed(struct pool *pool, const char *op, int r); 277 278 /* 279 * Target context for a pool. 280 */ 281 struct pool_c { 282 struct dm_target *ti; 283 struct pool *pool; 284 struct dm_dev *data_dev; 285 struct dm_dev *metadata_dev; 286 struct dm_target_callbacks callbacks; 287 288 dm_block_t low_water_blocks; 289 struct pool_features requested_pf; /* Features requested during table load */ 290 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */ 291 }; 292 293 /* 294 * Target context for a thin. 295 */ 296 struct thin_c { 297 struct list_head list; 298 struct dm_dev *pool_dev; 299 struct dm_dev *origin_dev; 300 sector_t origin_size; 301 dm_thin_id dev_id; 302 303 struct pool *pool; 304 struct dm_thin_device *td; 305 struct mapped_device *thin_md; 306 307 bool requeue_mode:1; 308 spinlock_t lock; 309 struct list_head deferred_cells; 310 struct bio_list deferred_bio_list; 311 struct bio_list retry_on_resume_list; 312 struct rb_root sort_bio_list; /* sorted list of deferred bios */ 313 314 /* 315 * Ensures the thin is not destroyed until the worker has finished 316 * iterating the active_thins list. 317 */ 318 atomic_t refcount; 319 struct completion can_destroy; 320 }; 321 322 /*----------------------------------------------------------------*/ 323 324 /** 325 * __blkdev_issue_discard_async - queue a discard with async completion 326 * @bdev: blockdev to issue discard for 327 * @sector: start sector 328 * @nr_sects: number of sectors to discard 329 * @gfp_mask: memory allocation flags (for bio_alloc) 330 * @flags: BLKDEV_IFL_* flags to control behaviour 331 * @parent_bio: parent discard bio that all sub discards get chained to 332 * 333 * Description: 334 * Asynchronously issue a discard request for the sectors in question. 335 * NOTE: this variant of blk-core's blkdev_issue_discard() is a stop-gap 336 * that is being kept local to DM thinp until the block changes to allow 337 * late bio splitting land upstream. 338 */ 339 static int __blkdev_issue_discard_async(struct block_device *bdev, sector_t sector, 340 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags, 341 struct bio *parent_bio) 342 { 343 struct request_queue *q = bdev_get_queue(bdev); 344 int type = REQ_WRITE | REQ_DISCARD; 345 unsigned int max_discard_sectors, granularity; 346 int alignment; 347 struct bio *bio; 348 int ret = 0; 349 struct blk_plug plug; 350 351 if (!q) 352 return -ENXIO; 353 354 if (!blk_queue_discard(q)) 355 return -EOPNOTSUPP; 356 357 /* Zero-sector (unknown) and one-sector granularities are the same. */ 358 granularity = max(q->limits.discard_granularity >> 9, 1U); 359 alignment = (bdev_discard_alignment(bdev) >> 9) % granularity; 360 361 /* 362 * Ensure that max_discard_sectors is of the proper 363 * granularity, so that requests stay aligned after a split. 364 */ 365 max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); 366 max_discard_sectors -= max_discard_sectors % granularity; 367 if (unlikely(!max_discard_sectors)) { 368 /* Avoid infinite loop below. Being cautious never hurts. */ 369 return -EOPNOTSUPP; 370 } 371 372 if (flags & BLKDEV_DISCARD_SECURE) { 373 if (!blk_queue_secdiscard(q)) 374 return -EOPNOTSUPP; 375 type |= REQ_SECURE; 376 } 377 378 blk_start_plug(&plug); 379 while (nr_sects) { 380 unsigned int req_sects; 381 sector_t end_sect, tmp; 382 383 /* 384 * Required bio_put occurs in bio_endio thanks to bio_chain below 385 */ 386 bio = bio_alloc(gfp_mask, 1); 387 if (!bio) { 388 ret = -ENOMEM; 389 break; 390 } 391 392 req_sects = min_t(sector_t, nr_sects, max_discard_sectors); 393 394 /* 395 * If splitting a request, and the next starting sector would be 396 * misaligned, stop the discard at the previous aligned sector. 397 */ 398 end_sect = sector + req_sects; 399 tmp = end_sect; 400 if (req_sects < nr_sects && 401 sector_div(tmp, granularity) != alignment) { 402 end_sect = end_sect - alignment; 403 sector_div(end_sect, granularity); 404 end_sect = end_sect * granularity + alignment; 405 req_sects = end_sect - sector; 406 } 407 408 bio_chain(bio, parent_bio); 409 410 bio->bi_iter.bi_sector = sector; 411 bio->bi_bdev = bdev; 412 413 bio->bi_iter.bi_size = req_sects << 9; 414 nr_sects -= req_sects; 415 sector = end_sect; 416 417 submit_bio(type, bio); 418 419 /* 420 * We can loop for a long time in here, if someone does 421 * full device discards (like mkfs). Be nice and allow 422 * us to schedule out to avoid softlocking if preempt 423 * is disabled. 424 */ 425 cond_resched(); 426 } 427 blk_finish_plug(&plug); 428 429 return ret; 430 } 431 432 static bool block_size_is_power_of_two(struct pool *pool) 433 { 434 return pool->sectors_per_block_shift >= 0; 435 } 436 437 static sector_t block_to_sectors(struct pool *pool, dm_block_t b) 438 { 439 return block_size_is_power_of_two(pool) ? 440 (b << pool->sectors_per_block_shift) : 441 (b * pool->sectors_per_block); 442 } 443 444 static int issue_discard(struct thin_c *tc, dm_block_t data_b, dm_block_t data_e, 445 struct bio *parent_bio) 446 { 447 sector_t s = block_to_sectors(tc->pool, data_b); 448 sector_t len = block_to_sectors(tc->pool, data_e - data_b); 449 450 return __blkdev_issue_discard_async(tc->pool_dev->bdev, s, len, 451 GFP_NOWAIT, 0, parent_bio); 452 } 453 454 /*----------------------------------------------------------------*/ 455 456 /* 457 * wake_worker() is used when new work is queued and when pool_resume is 458 * ready to continue deferred IO processing. 459 */ 460 static void wake_worker(struct pool *pool) 461 { 462 queue_work(pool->wq, &pool->worker); 463 } 464 465 /*----------------------------------------------------------------*/ 466 467 static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio, 468 struct dm_bio_prison_cell **cell_result) 469 { 470 int r; 471 struct dm_bio_prison_cell *cell_prealloc; 472 473 /* 474 * Allocate a cell from the prison's mempool. 475 * This might block but it can't fail. 476 */ 477 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO); 478 479 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result); 480 if (r) 481 /* 482 * We reused an old cell; we can get rid of 483 * the new one. 484 */ 485 dm_bio_prison_free_cell(pool->prison, cell_prealloc); 486 487 return r; 488 } 489 490 static void cell_release(struct pool *pool, 491 struct dm_bio_prison_cell *cell, 492 struct bio_list *bios) 493 { 494 dm_cell_release(pool->prison, cell, bios); 495 dm_bio_prison_free_cell(pool->prison, cell); 496 } 497 498 static void cell_visit_release(struct pool *pool, 499 void (*fn)(void *, struct dm_bio_prison_cell *), 500 void *context, 501 struct dm_bio_prison_cell *cell) 502 { 503 dm_cell_visit_release(pool->prison, fn, context, cell); 504 dm_bio_prison_free_cell(pool->prison, cell); 505 } 506 507 static void cell_release_no_holder(struct pool *pool, 508 struct dm_bio_prison_cell *cell, 509 struct bio_list *bios) 510 { 511 dm_cell_release_no_holder(pool->prison, cell, bios); 512 dm_bio_prison_free_cell(pool->prison, cell); 513 } 514 515 static void cell_error_with_code(struct pool *pool, 516 struct dm_bio_prison_cell *cell, int error_code) 517 { 518 dm_cell_error(pool->prison, cell, error_code); 519 dm_bio_prison_free_cell(pool->prison, cell); 520 } 521 522 static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell) 523 { 524 cell_error_with_code(pool, cell, -EIO); 525 } 526 527 static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell) 528 { 529 cell_error_with_code(pool, cell, 0); 530 } 531 532 static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell) 533 { 534 cell_error_with_code(pool, cell, DM_ENDIO_REQUEUE); 535 } 536 537 /*----------------------------------------------------------------*/ 538 539 /* 540 * A global list of pools that uses a struct mapped_device as a key. 541 */ 542 static struct dm_thin_pool_table { 543 struct mutex mutex; 544 struct list_head pools; 545 } dm_thin_pool_table; 546 547 static void pool_table_init(void) 548 { 549 mutex_init(&dm_thin_pool_table.mutex); 550 INIT_LIST_HEAD(&dm_thin_pool_table.pools); 551 } 552 553 static void __pool_table_insert(struct pool *pool) 554 { 555 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); 556 list_add(&pool->list, &dm_thin_pool_table.pools); 557 } 558 559 static void __pool_table_remove(struct pool *pool) 560 { 561 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); 562 list_del(&pool->list); 563 } 564 565 static struct pool *__pool_table_lookup(struct mapped_device *md) 566 { 567 struct pool *pool = NULL, *tmp; 568 569 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); 570 571 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) { 572 if (tmp->pool_md == md) { 573 pool = tmp; 574 break; 575 } 576 } 577 578 return pool; 579 } 580 581 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev) 582 { 583 struct pool *pool = NULL, *tmp; 584 585 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); 586 587 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) { 588 if (tmp->md_dev == md_dev) { 589 pool = tmp; 590 break; 591 } 592 } 593 594 return pool; 595 } 596 597 /*----------------------------------------------------------------*/ 598 599 struct dm_thin_endio_hook { 600 struct thin_c *tc; 601 struct dm_deferred_entry *shared_read_entry; 602 struct dm_deferred_entry *all_io_entry; 603 struct dm_thin_new_mapping *overwrite_mapping; 604 struct rb_node rb_node; 605 struct dm_bio_prison_cell *cell; 606 }; 607 608 static void __merge_bio_list(struct bio_list *bios, struct bio_list *master) 609 { 610 bio_list_merge(bios, master); 611 bio_list_init(master); 612 } 613 614 static void error_bio_list(struct bio_list *bios, int error) 615 { 616 struct bio *bio; 617 618 while ((bio = bio_list_pop(bios))) 619 bio_endio(bio, error); 620 } 621 622 static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master, int error) 623 { 624 struct bio_list bios; 625 unsigned long flags; 626 627 bio_list_init(&bios); 628 629 spin_lock_irqsave(&tc->lock, flags); 630 __merge_bio_list(&bios, master); 631 spin_unlock_irqrestore(&tc->lock, flags); 632 633 error_bio_list(&bios, error); 634 } 635 636 static void requeue_deferred_cells(struct thin_c *tc) 637 { 638 struct pool *pool = tc->pool; 639 unsigned long flags; 640 struct list_head cells; 641 struct dm_bio_prison_cell *cell, *tmp; 642 643 INIT_LIST_HEAD(&cells); 644 645 spin_lock_irqsave(&tc->lock, flags); 646 list_splice_init(&tc->deferred_cells, &cells); 647 spin_unlock_irqrestore(&tc->lock, flags); 648 649 list_for_each_entry_safe(cell, tmp, &cells, user_list) 650 cell_requeue(pool, cell); 651 } 652 653 static void requeue_io(struct thin_c *tc) 654 { 655 struct bio_list bios; 656 unsigned long flags; 657 658 bio_list_init(&bios); 659 660 spin_lock_irqsave(&tc->lock, flags); 661 __merge_bio_list(&bios, &tc->deferred_bio_list); 662 __merge_bio_list(&bios, &tc->retry_on_resume_list); 663 spin_unlock_irqrestore(&tc->lock, flags); 664 665 error_bio_list(&bios, DM_ENDIO_REQUEUE); 666 requeue_deferred_cells(tc); 667 } 668 669 static void error_retry_list_with_code(struct pool *pool, int error) 670 { 671 struct thin_c *tc; 672 673 rcu_read_lock(); 674 list_for_each_entry_rcu(tc, &pool->active_thins, list) 675 error_thin_bio_list(tc, &tc->retry_on_resume_list, error); 676 rcu_read_unlock(); 677 } 678 679 static void error_retry_list(struct pool *pool) 680 { 681 return error_retry_list_with_code(pool, -EIO); 682 } 683 684 /* 685 * This section of code contains the logic for processing a thin device's IO. 686 * Much of the code depends on pool object resources (lists, workqueues, etc) 687 * but most is exclusively called from the thin target rather than the thin-pool 688 * target. 689 */ 690 691 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio) 692 { 693 struct pool *pool = tc->pool; 694 sector_t block_nr = bio->bi_iter.bi_sector; 695 696 if (block_size_is_power_of_two(pool)) 697 block_nr >>= pool->sectors_per_block_shift; 698 else 699 (void) sector_div(block_nr, pool->sectors_per_block); 700 701 return block_nr; 702 } 703 704 /* 705 * Returns the _complete_ blocks that this bio covers. 706 */ 707 static void get_bio_block_range(struct thin_c *tc, struct bio *bio, 708 dm_block_t *begin, dm_block_t *end) 709 { 710 struct pool *pool = tc->pool; 711 sector_t b = bio->bi_iter.bi_sector; 712 sector_t e = b + (bio->bi_iter.bi_size >> SECTOR_SHIFT); 713 714 b += pool->sectors_per_block - 1ull; /* so we round up */ 715 716 if (block_size_is_power_of_two(pool)) { 717 b >>= pool->sectors_per_block_shift; 718 e >>= pool->sectors_per_block_shift; 719 } else { 720 (void) sector_div(b, pool->sectors_per_block); 721 (void) sector_div(e, pool->sectors_per_block); 722 } 723 724 if (e < b) 725 /* Can happen if the bio is within a single block. */ 726 e = b; 727 728 *begin = b; 729 *end = e; 730 } 731 732 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block) 733 { 734 struct pool *pool = tc->pool; 735 sector_t bi_sector = bio->bi_iter.bi_sector; 736 737 bio->bi_bdev = tc->pool_dev->bdev; 738 if (block_size_is_power_of_two(pool)) 739 bio->bi_iter.bi_sector = 740 (block << pool->sectors_per_block_shift) | 741 (bi_sector & (pool->sectors_per_block - 1)); 742 else 743 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) + 744 sector_div(bi_sector, pool->sectors_per_block); 745 } 746 747 static void remap_to_origin(struct thin_c *tc, struct bio *bio) 748 { 749 bio->bi_bdev = tc->origin_dev->bdev; 750 } 751 752 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio) 753 { 754 return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) && 755 dm_thin_changed_this_transaction(tc->td); 756 } 757 758 static void inc_all_io_entry(struct pool *pool, struct bio *bio) 759 { 760 struct dm_thin_endio_hook *h; 761 762 if (bio->bi_rw & REQ_DISCARD) 763 return; 764 765 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 766 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds); 767 } 768 769 static void issue(struct thin_c *tc, struct bio *bio) 770 { 771 struct pool *pool = tc->pool; 772 unsigned long flags; 773 774 if (!bio_triggers_commit(tc, bio)) { 775 generic_make_request(bio); 776 return; 777 } 778 779 /* 780 * Complete bio with an error if earlier I/O caused changes to 781 * the metadata that can't be committed e.g, due to I/O errors 782 * on the metadata device. 783 */ 784 if (dm_thin_aborted_changes(tc->td)) { 785 bio_io_error(bio); 786 return; 787 } 788 789 /* 790 * Batch together any bios that trigger commits and then issue a 791 * single commit for them in process_deferred_bios(). 792 */ 793 spin_lock_irqsave(&pool->lock, flags); 794 bio_list_add(&pool->deferred_flush_bios, bio); 795 spin_unlock_irqrestore(&pool->lock, flags); 796 } 797 798 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio) 799 { 800 remap_to_origin(tc, bio); 801 issue(tc, bio); 802 } 803 804 static void remap_and_issue(struct thin_c *tc, struct bio *bio, 805 dm_block_t block) 806 { 807 remap(tc, bio, block); 808 issue(tc, bio); 809 } 810 811 /*----------------------------------------------------------------*/ 812 813 /* 814 * Bio endio functions. 815 */ 816 struct dm_thin_new_mapping { 817 struct list_head list; 818 819 bool pass_discard:1; 820 bool maybe_shared:1; 821 822 /* 823 * Track quiescing, copying and zeroing preparation actions. When this 824 * counter hits zero the block is prepared and can be inserted into the 825 * btree. 826 */ 827 atomic_t prepare_actions; 828 829 int err; 830 struct thin_c *tc; 831 dm_block_t virt_begin, virt_end; 832 dm_block_t data_block; 833 struct dm_bio_prison_cell *cell; 834 835 /* 836 * If the bio covers the whole area of a block then we can avoid 837 * zeroing or copying. Instead this bio is hooked. The bio will 838 * still be in the cell, so care has to be taken to avoid issuing 839 * the bio twice. 840 */ 841 struct bio *bio; 842 bio_end_io_t *saved_bi_end_io; 843 }; 844 845 static void __complete_mapping_preparation(struct dm_thin_new_mapping *m) 846 { 847 struct pool *pool = m->tc->pool; 848 849 if (atomic_dec_and_test(&m->prepare_actions)) { 850 list_add_tail(&m->list, &pool->prepared_mappings); 851 wake_worker(pool); 852 } 853 } 854 855 static void complete_mapping_preparation(struct dm_thin_new_mapping *m) 856 { 857 unsigned long flags; 858 struct pool *pool = m->tc->pool; 859 860 spin_lock_irqsave(&pool->lock, flags); 861 __complete_mapping_preparation(m); 862 spin_unlock_irqrestore(&pool->lock, flags); 863 } 864 865 static void copy_complete(int read_err, unsigned long write_err, void *context) 866 { 867 struct dm_thin_new_mapping *m = context; 868 869 m->err = read_err || write_err ? -EIO : 0; 870 complete_mapping_preparation(m); 871 } 872 873 static void overwrite_endio(struct bio *bio, int err) 874 { 875 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 876 struct dm_thin_new_mapping *m = h->overwrite_mapping; 877 878 bio->bi_end_io = m->saved_bi_end_io; 879 880 m->err = err; 881 complete_mapping_preparation(m); 882 } 883 884 /*----------------------------------------------------------------*/ 885 886 /* 887 * Workqueue. 888 */ 889 890 /* 891 * Prepared mapping jobs. 892 */ 893 894 /* 895 * This sends the bios in the cell, except the original holder, back 896 * to the deferred_bios list. 897 */ 898 static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell) 899 { 900 struct pool *pool = tc->pool; 901 unsigned long flags; 902 903 spin_lock_irqsave(&tc->lock, flags); 904 cell_release_no_holder(pool, cell, &tc->deferred_bio_list); 905 spin_unlock_irqrestore(&tc->lock, flags); 906 907 wake_worker(pool); 908 } 909 910 static void thin_defer_bio(struct thin_c *tc, struct bio *bio); 911 912 struct remap_info { 913 struct thin_c *tc; 914 struct bio_list defer_bios; 915 struct bio_list issue_bios; 916 }; 917 918 static void __inc_remap_and_issue_cell(void *context, 919 struct dm_bio_prison_cell *cell) 920 { 921 struct remap_info *info = context; 922 struct bio *bio; 923 924 while ((bio = bio_list_pop(&cell->bios))) { 925 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) 926 bio_list_add(&info->defer_bios, bio); 927 else { 928 inc_all_io_entry(info->tc->pool, bio); 929 930 /* 931 * We can't issue the bios with the bio prison lock 932 * held, so we add them to a list to issue on 933 * return from this function. 934 */ 935 bio_list_add(&info->issue_bios, bio); 936 } 937 } 938 } 939 940 static void inc_remap_and_issue_cell(struct thin_c *tc, 941 struct dm_bio_prison_cell *cell, 942 dm_block_t block) 943 { 944 struct bio *bio; 945 struct remap_info info; 946 947 info.tc = tc; 948 bio_list_init(&info.defer_bios); 949 bio_list_init(&info.issue_bios); 950 951 /* 952 * We have to be careful to inc any bios we're about to issue 953 * before the cell is released, and avoid a race with new bios 954 * being added to the cell. 955 */ 956 cell_visit_release(tc->pool, __inc_remap_and_issue_cell, 957 &info, cell); 958 959 while ((bio = bio_list_pop(&info.defer_bios))) 960 thin_defer_bio(tc, bio); 961 962 while ((bio = bio_list_pop(&info.issue_bios))) 963 remap_and_issue(info.tc, bio, block); 964 } 965 966 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m) 967 { 968 cell_error(m->tc->pool, m->cell); 969 list_del(&m->list); 970 mempool_free(m, m->tc->pool->mapping_pool); 971 } 972 973 static void process_prepared_mapping(struct dm_thin_new_mapping *m) 974 { 975 struct thin_c *tc = m->tc; 976 struct pool *pool = tc->pool; 977 struct bio *bio = m->bio; 978 int r; 979 980 if (m->err) { 981 cell_error(pool, m->cell); 982 goto out; 983 } 984 985 /* 986 * Commit the prepared block into the mapping btree. 987 * Any I/O for this block arriving after this point will get 988 * remapped to it directly. 989 */ 990 r = dm_thin_insert_block(tc->td, m->virt_begin, m->data_block); 991 if (r) { 992 metadata_operation_failed(pool, "dm_thin_insert_block", r); 993 cell_error(pool, m->cell); 994 goto out; 995 } 996 997 /* 998 * Release any bios held while the block was being provisioned. 999 * If we are processing a write bio that completely covers the block, 1000 * we already processed it so can ignore it now when processing 1001 * the bios in the cell. 1002 */ 1003 if (bio) { 1004 inc_remap_and_issue_cell(tc, m->cell, m->data_block); 1005 bio_endio(bio, 0); 1006 } else { 1007 inc_all_io_entry(tc->pool, m->cell->holder); 1008 remap_and_issue(tc, m->cell->holder, m->data_block); 1009 inc_remap_and_issue_cell(tc, m->cell, m->data_block); 1010 } 1011 1012 out: 1013 list_del(&m->list); 1014 mempool_free(m, pool->mapping_pool); 1015 } 1016 1017 /*----------------------------------------------------------------*/ 1018 1019 static void free_discard_mapping(struct dm_thin_new_mapping *m) 1020 { 1021 struct thin_c *tc = m->tc; 1022 if (m->cell) 1023 cell_defer_no_holder(tc, m->cell); 1024 mempool_free(m, tc->pool->mapping_pool); 1025 } 1026 1027 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m) 1028 { 1029 bio_io_error(m->bio); 1030 free_discard_mapping(m); 1031 } 1032 1033 static void process_prepared_discard_success(struct dm_thin_new_mapping *m) 1034 { 1035 bio_endio(m->bio, 0); 1036 free_discard_mapping(m); 1037 } 1038 1039 static void process_prepared_discard_no_passdown(struct dm_thin_new_mapping *m) 1040 { 1041 int r; 1042 struct thin_c *tc = m->tc; 1043 1044 r = dm_thin_remove_range(tc->td, m->cell->key.block_begin, m->cell->key.block_end); 1045 if (r) { 1046 metadata_operation_failed(tc->pool, "dm_thin_remove_range", r); 1047 bio_io_error(m->bio); 1048 } else 1049 bio_endio(m->bio, 0); 1050 1051 cell_defer_no_holder(tc, m->cell); 1052 mempool_free(m, tc->pool->mapping_pool); 1053 } 1054 1055 static int passdown_double_checking_shared_status(struct dm_thin_new_mapping *m) 1056 { 1057 /* 1058 * We've already unmapped this range of blocks, but before we 1059 * passdown we have to check that these blocks are now unused. 1060 */ 1061 int r; 1062 bool used = true; 1063 struct thin_c *tc = m->tc; 1064 struct pool *pool = tc->pool; 1065 dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin; 1066 1067 while (b != end) { 1068 /* find start of unmapped run */ 1069 for (; b < end; b++) { 1070 r = dm_pool_block_is_used(pool->pmd, b, &used); 1071 if (r) 1072 return r; 1073 1074 if (!used) 1075 break; 1076 } 1077 1078 if (b == end) 1079 break; 1080 1081 /* find end of run */ 1082 for (e = b + 1; e != end; e++) { 1083 r = dm_pool_block_is_used(pool->pmd, e, &used); 1084 if (r) 1085 return r; 1086 1087 if (used) 1088 break; 1089 } 1090 1091 r = issue_discard(tc, b, e, m->bio); 1092 if (r) 1093 return r; 1094 1095 b = e; 1096 } 1097 1098 return 0; 1099 } 1100 1101 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m) 1102 { 1103 int r; 1104 struct thin_c *tc = m->tc; 1105 struct pool *pool = tc->pool; 1106 1107 r = dm_thin_remove_range(tc->td, m->virt_begin, m->virt_end); 1108 if (r) 1109 metadata_operation_failed(pool, "dm_thin_remove_range", r); 1110 1111 else if (m->maybe_shared) 1112 r = passdown_double_checking_shared_status(m); 1113 else 1114 r = issue_discard(tc, m->data_block, m->data_block + (m->virt_end - m->virt_begin), m->bio); 1115 1116 /* 1117 * Even if r is set, there could be sub discards in flight that we 1118 * need to wait for. 1119 */ 1120 bio_endio(m->bio, r); 1121 cell_defer_no_holder(tc, m->cell); 1122 mempool_free(m, pool->mapping_pool); 1123 } 1124 1125 static void process_prepared(struct pool *pool, struct list_head *head, 1126 process_mapping_fn *fn) 1127 { 1128 unsigned long flags; 1129 struct list_head maps; 1130 struct dm_thin_new_mapping *m, *tmp; 1131 1132 INIT_LIST_HEAD(&maps); 1133 spin_lock_irqsave(&pool->lock, flags); 1134 list_splice_init(head, &maps); 1135 spin_unlock_irqrestore(&pool->lock, flags); 1136 1137 list_for_each_entry_safe(m, tmp, &maps, list) 1138 (*fn)(m); 1139 } 1140 1141 /* 1142 * Deferred bio jobs. 1143 */ 1144 static int io_overlaps_block(struct pool *pool, struct bio *bio) 1145 { 1146 return bio->bi_iter.bi_size == 1147 (pool->sectors_per_block << SECTOR_SHIFT); 1148 } 1149 1150 static int io_overwrites_block(struct pool *pool, struct bio *bio) 1151 { 1152 return (bio_data_dir(bio) == WRITE) && 1153 io_overlaps_block(pool, bio); 1154 } 1155 1156 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save, 1157 bio_end_io_t *fn) 1158 { 1159 *save = bio->bi_end_io; 1160 bio->bi_end_io = fn; 1161 } 1162 1163 static int ensure_next_mapping(struct pool *pool) 1164 { 1165 if (pool->next_mapping) 1166 return 0; 1167 1168 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC); 1169 1170 return pool->next_mapping ? 0 : -ENOMEM; 1171 } 1172 1173 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool) 1174 { 1175 struct dm_thin_new_mapping *m = pool->next_mapping; 1176 1177 BUG_ON(!pool->next_mapping); 1178 1179 memset(m, 0, sizeof(struct dm_thin_new_mapping)); 1180 INIT_LIST_HEAD(&m->list); 1181 m->bio = NULL; 1182 1183 pool->next_mapping = NULL; 1184 1185 return m; 1186 } 1187 1188 static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m, 1189 sector_t begin, sector_t end) 1190 { 1191 int r; 1192 struct dm_io_region to; 1193 1194 to.bdev = tc->pool_dev->bdev; 1195 to.sector = begin; 1196 to.count = end - begin; 1197 1198 r = dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m); 1199 if (r < 0) { 1200 DMERR_LIMIT("dm_kcopyd_zero() failed"); 1201 copy_complete(1, 1, m); 1202 } 1203 } 1204 1205 static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio, 1206 dm_block_t data_begin, 1207 struct dm_thin_new_mapping *m) 1208 { 1209 struct pool *pool = tc->pool; 1210 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 1211 1212 h->overwrite_mapping = m; 1213 m->bio = bio; 1214 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); 1215 inc_all_io_entry(pool, bio); 1216 remap_and_issue(tc, bio, data_begin); 1217 } 1218 1219 /* 1220 * A partial copy also needs to zero the uncopied region. 1221 */ 1222 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, 1223 struct dm_dev *origin, dm_block_t data_origin, 1224 dm_block_t data_dest, 1225 struct dm_bio_prison_cell *cell, struct bio *bio, 1226 sector_t len) 1227 { 1228 int r; 1229 struct pool *pool = tc->pool; 1230 struct dm_thin_new_mapping *m = get_next_mapping(pool); 1231 1232 m->tc = tc; 1233 m->virt_begin = virt_block; 1234 m->virt_end = virt_block + 1u; 1235 m->data_block = data_dest; 1236 m->cell = cell; 1237 1238 /* 1239 * quiesce action + copy action + an extra reference held for the 1240 * duration of this function (we may need to inc later for a 1241 * partial zero). 1242 */ 1243 atomic_set(&m->prepare_actions, 3); 1244 1245 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list)) 1246 complete_mapping_preparation(m); /* already quiesced */ 1247 1248 /* 1249 * IO to pool_dev remaps to the pool target's data_dev. 1250 * 1251 * If the whole block of data is being overwritten, we can issue the 1252 * bio immediately. Otherwise we use kcopyd to clone the data first. 1253 */ 1254 if (io_overwrites_block(pool, bio)) 1255 remap_and_issue_overwrite(tc, bio, data_dest, m); 1256 else { 1257 struct dm_io_region from, to; 1258 1259 from.bdev = origin->bdev; 1260 from.sector = data_origin * pool->sectors_per_block; 1261 from.count = len; 1262 1263 to.bdev = tc->pool_dev->bdev; 1264 to.sector = data_dest * pool->sectors_per_block; 1265 to.count = len; 1266 1267 r = dm_kcopyd_copy(pool->copier, &from, 1, &to, 1268 0, copy_complete, m); 1269 if (r < 0) { 1270 DMERR_LIMIT("dm_kcopyd_copy() failed"); 1271 copy_complete(1, 1, m); 1272 1273 /* 1274 * We allow the zero to be issued, to simplify the 1275 * error path. Otherwise we'd need to start 1276 * worrying about decrementing the prepare_actions 1277 * counter. 1278 */ 1279 } 1280 1281 /* 1282 * Do we need to zero a tail region? 1283 */ 1284 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) { 1285 atomic_inc(&m->prepare_actions); 1286 ll_zero(tc, m, 1287 data_dest * pool->sectors_per_block + len, 1288 (data_dest + 1) * pool->sectors_per_block); 1289 } 1290 } 1291 1292 complete_mapping_preparation(m); /* drop our ref */ 1293 } 1294 1295 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block, 1296 dm_block_t data_origin, dm_block_t data_dest, 1297 struct dm_bio_prison_cell *cell, struct bio *bio) 1298 { 1299 schedule_copy(tc, virt_block, tc->pool_dev, 1300 data_origin, data_dest, cell, bio, 1301 tc->pool->sectors_per_block); 1302 } 1303 1304 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, 1305 dm_block_t data_block, struct dm_bio_prison_cell *cell, 1306 struct bio *bio) 1307 { 1308 struct pool *pool = tc->pool; 1309 struct dm_thin_new_mapping *m = get_next_mapping(pool); 1310 1311 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */ 1312 m->tc = tc; 1313 m->virt_begin = virt_block; 1314 m->virt_end = virt_block + 1u; 1315 m->data_block = data_block; 1316 m->cell = cell; 1317 1318 /* 1319 * If the whole block of data is being overwritten or we are not 1320 * zeroing pre-existing data, we can issue the bio immediately. 1321 * Otherwise we use kcopyd to zero the data first. 1322 */ 1323 if (pool->pf.zero_new_blocks) { 1324 if (io_overwrites_block(pool, bio)) 1325 remap_and_issue_overwrite(tc, bio, data_block, m); 1326 else 1327 ll_zero(tc, m, data_block * pool->sectors_per_block, 1328 (data_block + 1) * pool->sectors_per_block); 1329 } else 1330 process_prepared_mapping(m); 1331 } 1332 1333 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block, 1334 dm_block_t data_dest, 1335 struct dm_bio_prison_cell *cell, struct bio *bio) 1336 { 1337 struct pool *pool = tc->pool; 1338 sector_t virt_block_begin = virt_block * pool->sectors_per_block; 1339 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block; 1340 1341 if (virt_block_end <= tc->origin_size) 1342 schedule_copy(tc, virt_block, tc->origin_dev, 1343 virt_block, data_dest, cell, bio, 1344 pool->sectors_per_block); 1345 1346 else if (virt_block_begin < tc->origin_size) 1347 schedule_copy(tc, virt_block, tc->origin_dev, 1348 virt_block, data_dest, cell, bio, 1349 tc->origin_size - virt_block_begin); 1350 1351 else 1352 schedule_zero(tc, virt_block, data_dest, cell, bio); 1353 } 1354 1355 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode); 1356 1357 static void check_for_space(struct pool *pool) 1358 { 1359 int r; 1360 dm_block_t nr_free; 1361 1362 if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE) 1363 return; 1364 1365 r = dm_pool_get_free_block_count(pool->pmd, &nr_free); 1366 if (r) 1367 return; 1368 1369 if (nr_free) 1370 set_pool_mode(pool, PM_WRITE); 1371 } 1372 1373 /* 1374 * A non-zero return indicates read_only or fail_io mode. 1375 * Many callers don't care about the return value. 1376 */ 1377 static int commit(struct pool *pool) 1378 { 1379 int r; 1380 1381 if (get_pool_mode(pool) >= PM_READ_ONLY) 1382 return -EINVAL; 1383 1384 r = dm_pool_commit_metadata(pool->pmd); 1385 if (r) 1386 metadata_operation_failed(pool, "dm_pool_commit_metadata", r); 1387 else 1388 check_for_space(pool); 1389 1390 return r; 1391 } 1392 1393 static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks) 1394 { 1395 unsigned long flags; 1396 1397 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) { 1398 DMWARN("%s: reached low water mark for data device: sending event.", 1399 dm_device_name(pool->pool_md)); 1400 spin_lock_irqsave(&pool->lock, flags); 1401 pool->low_water_triggered = true; 1402 spin_unlock_irqrestore(&pool->lock, flags); 1403 dm_table_event(pool->ti->table); 1404 } 1405 } 1406 1407 static int alloc_data_block(struct thin_c *tc, dm_block_t *result) 1408 { 1409 int r; 1410 dm_block_t free_blocks; 1411 struct pool *pool = tc->pool; 1412 1413 if (WARN_ON(get_pool_mode(pool) != PM_WRITE)) 1414 return -EINVAL; 1415 1416 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); 1417 if (r) { 1418 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r); 1419 return r; 1420 } 1421 1422 check_low_water_mark(pool, free_blocks); 1423 1424 if (!free_blocks) { 1425 /* 1426 * Try to commit to see if that will free up some 1427 * more space. 1428 */ 1429 r = commit(pool); 1430 if (r) 1431 return r; 1432 1433 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); 1434 if (r) { 1435 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r); 1436 return r; 1437 } 1438 1439 if (!free_blocks) { 1440 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE); 1441 return -ENOSPC; 1442 } 1443 } 1444 1445 r = dm_pool_alloc_data_block(pool->pmd, result); 1446 if (r) { 1447 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r); 1448 return r; 1449 } 1450 1451 return 0; 1452 } 1453 1454 /* 1455 * If we have run out of space, queue bios until the device is 1456 * resumed, presumably after having been reloaded with more space. 1457 */ 1458 static void retry_on_resume(struct bio *bio) 1459 { 1460 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 1461 struct thin_c *tc = h->tc; 1462 unsigned long flags; 1463 1464 spin_lock_irqsave(&tc->lock, flags); 1465 bio_list_add(&tc->retry_on_resume_list, bio); 1466 spin_unlock_irqrestore(&tc->lock, flags); 1467 } 1468 1469 static int should_error_unserviceable_bio(struct pool *pool) 1470 { 1471 enum pool_mode m = get_pool_mode(pool); 1472 1473 switch (m) { 1474 case PM_WRITE: 1475 /* Shouldn't get here */ 1476 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode"); 1477 return -EIO; 1478 1479 case PM_OUT_OF_DATA_SPACE: 1480 return pool->pf.error_if_no_space ? -ENOSPC : 0; 1481 1482 case PM_READ_ONLY: 1483 case PM_FAIL: 1484 return -EIO; 1485 default: 1486 /* Shouldn't get here */ 1487 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode"); 1488 return -EIO; 1489 } 1490 } 1491 1492 static void handle_unserviceable_bio(struct pool *pool, struct bio *bio) 1493 { 1494 int error = should_error_unserviceable_bio(pool); 1495 1496 if (error) 1497 bio_endio(bio, error); 1498 else 1499 retry_on_resume(bio); 1500 } 1501 1502 static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell) 1503 { 1504 struct bio *bio; 1505 struct bio_list bios; 1506 int error; 1507 1508 error = should_error_unserviceable_bio(pool); 1509 if (error) { 1510 cell_error_with_code(pool, cell, error); 1511 return; 1512 } 1513 1514 bio_list_init(&bios); 1515 cell_release(pool, cell, &bios); 1516 1517 while ((bio = bio_list_pop(&bios))) 1518 retry_on_resume(bio); 1519 } 1520 1521 static void process_discard_cell_no_passdown(struct thin_c *tc, 1522 struct dm_bio_prison_cell *virt_cell) 1523 { 1524 struct pool *pool = tc->pool; 1525 struct dm_thin_new_mapping *m = get_next_mapping(pool); 1526 1527 /* 1528 * We don't need to lock the data blocks, since there's no 1529 * passdown. We only lock data blocks for allocation and breaking sharing. 1530 */ 1531 m->tc = tc; 1532 m->virt_begin = virt_cell->key.block_begin; 1533 m->virt_end = virt_cell->key.block_end; 1534 m->cell = virt_cell; 1535 m->bio = virt_cell->holder; 1536 1537 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) 1538 pool->process_prepared_discard(m); 1539 } 1540 1541 /* 1542 * FIXME: DM local hack to defer parent bios's end_io until we 1543 * _know_ all chained sub range discard bios have completed. 1544 * Will go away once late bio splitting lands upstream! 1545 */ 1546 static inline void __bio_inc_remaining(struct bio *bio) 1547 { 1548 bio->bi_flags |= (1 << BIO_CHAIN); 1549 smp_mb__before_atomic(); 1550 atomic_inc(&bio->__bi_remaining); 1551 } 1552 1553 static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t end, 1554 struct bio *bio) 1555 { 1556 struct pool *pool = tc->pool; 1557 1558 int r; 1559 bool maybe_shared; 1560 struct dm_cell_key data_key; 1561 struct dm_bio_prison_cell *data_cell; 1562 struct dm_thin_new_mapping *m; 1563 dm_block_t virt_begin, virt_end, data_begin; 1564 1565 while (begin != end) { 1566 r = ensure_next_mapping(pool); 1567 if (r) 1568 /* we did our best */ 1569 return; 1570 1571 r = dm_thin_find_mapped_range(tc->td, begin, end, &virt_begin, &virt_end, 1572 &data_begin, &maybe_shared); 1573 if (r) 1574 /* 1575 * Silently fail, letting any mappings we've 1576 * created complete. 1577 */ 1578 break; 1579 1580 build_key(tc->td, PHYSICAL, data_begin, data_begin + (virt_end - virt_begin), &data_key); 1581 if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) { 1582 /* contention, we'll give up with this range */ 1583 begin = virt_end; 1584 continue; 1585 } 1586 1587 /* 1588 * IO may still be going to the destination block. We must 1589 * quiesce before we can do the removal. 1590 */ 1591 m = get_next_mapping(pool); 1592 m->tc = tc; 1593 m->maybe_shared = maybe_shared; 1594 m->virt_begin = virt_begin; 1595 m->virt_end = virt_end; 1596 m->data_block = data_begin; 1597 m->cell = data_cell; 1598 m->bio = bio; 1599 1600 /* 1601 * The parent bio must not complete before sub discard bios are 1602 * chained to it (see __blkdev_issue_discard_async's bio_chain)! 1603 * 1604 * This per-mapping bi_remaining increment is paired with 1605 * the implicit decrement that occurs via bio_endio() in 1606 * process_prepared_discard_{passdown,no_passdown}. 1607 */ 1608 __bio_inc_remaining(bio); 1609 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) 1610 pool->process_prepared_discard(m); 1611 1612 begin = virt_end; 1613 } 1614 } 1615 1616 static void process_discard_cell_passdown(struct thin_c *tc, struct dm_bio_prison_cell *virt_cell) 1617 { 1618 struct bio *bio = virt_cell->holder; 1619 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 1620 1621 /* 1622 * The virt_cell will only get freed once the origin bio completes. 1623 * This means it will remain locked while all the individual 1624 * passdown bios are in flight. 1625 */ 1626 h->cell = virt_cell; 1627 break_up_discard_bio(tc, virt_cell->key.block_begin, virt_cell->key.block_end, bio); 1628 1629 /* 1630 * We complete the bio now, knowing that the bi_remaining field 1631 * will prevent completion until the sub range discards have 1632 * completed. 1633 */ 1634 bio_endio(bio, 0); 1635 } 1636 1637 static void process_discard_bio(struct thin_c *tc, struct bio *bio) 1638 { 1639 dm_block_t begin, end; 1640 struct dm_cell_key virt_key; 1641 struct dm_bio_prison_cell *virt_cell; 1642 1643 get_bio_block_range(tc, bio, &begin, &end); 1644 if (begin == end) { 1645 /* 1646 * The discard covers less than a block. 1647 */ 1648 bio_endio(bio, 0); 1649 return; 1650 } 1651 1652 build_key(tc->td, VIRTUAL, begin, end, &virt_key); 1653 if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) 1654 /* 1655 * Potential starvation issue: We're relying on the 1656 * fs/application being well behaved, and not trying to 1657 * send IO to a region at the same time as discarding it. 1658 * If they do this persistently then it's possible this 1659 * cell will never be granted. 1660 */ 1661 return; 1662 1663 tc->pool->process_discard_cell(tc, virt_cell); 1664 } 1665 1666 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block, 1667 struct dm_cell_key *key, 1668 struct dm_thin_lookup_result *lookup_result, 1669 struct dm_bio_prison_cell *cell) 1670 { 1671 int r; 1672 dm_block_t data_block; 1673 struct pool *pool = tc->pool; 1674 1675 r = alloc_data_block(tc, &data_block); 1676 switch (r) { 1677 case 0: 1678 schedule_internal_copy(tc, block, lookup_result->block, 1679 data_block, cell, bio); 1680 break; 1681 1682 case -ENOSPC: 1683 retry_bios_on_resume(pool, cell); 1684 break; 1685 1686 default: 1687 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d", 1688 __func__, r); 1689 cell_error(pool, cell); 1690 break; 1691 } 1692 } 1693 1694 static void __remap_and_issue_shared_cell(void *context, 1695 struct dm_bio_prison_cell *cell) 1696 { 1697 struct remap_info *info = context; 1698 struct bio *bio; 1699 1700 while ((bio = bio_list_pop(&cell->bios))) { 1701 if ((bio_data_dir(bio) == WRITE) || 1702 (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA))) 1703 bio_list_add(&info->defer_bios, bio); 1704 else { 1705 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));; 1706 1707 h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds); 1708 inc_all_io_entry(info->tc->pool, bio); 1709 bio_list_add(&info->issue_bios, bio); 1710 } 1711 } 1712 } 1713 1714 static void remap_and_issue_shared_cell(struct thin_c *tc, 1715 struct dm_bio_prison_cell *cell, 1716 dm_block_t block) 1717 { 1718 struct bio *bio; 1719 struct remap_info info; 1720 1721 info.tc = tc; 1722 bio_list_init(&info.defer_bios); 1723 bio_list_init(&info.issue_bios); 1724 1725 cell_visit_release(tc->pool, __remap_and_issue_shared_cell, 1726 &info, cell); 1727 1728 while ((bio = bio_list_pop(&info.defer_bios))) 1729 thin_defer_bio(tc, bio); 1730 1731 while ((bio = bio_list_pop(&info.issue_bios))) 1732 remap_and_issue(tc, bio, block); 1733 } 1734 1735 static void process_shared_bio(struct thin_c *tc, struct bio *bio, 1736 dm_block_t block, 1737 struct dm_thin_lookup_result *lookup_result, 1738 struct dm_bio_prison_cell *virt_cell) 1739 { 1740 struct dm_bio_prison_cell *data_cell; 1741 struct pool *pool = tc->pool; 1742 struct dm_cell_key key; 1743 1744 /* 1745 * If cell is already occupied, then sharing is already in the process 1746 * of being broken so we have nothing further to do here. 1747 */ 1748 build_data_key(tc->td, lookup_result->block, &key); 1749 if (bio_detain(pool, &key, bio, &data_cell)) { 1750 cell_defer_no_holder(tc, virt_cell); 1751 return; 1752 } 1753 1754 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) { 1755 break_sharing(tc, bio, block, &key, lookup_result, data_cell); 1756 cell_defer_no_holder(tc, virt_cell); 1757 } else { 1758 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 1759 1760 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds); 1761 inc_all_io_entry(pool, bio); 1762 remap_and_issue(tc, bio, lookup_result->block); 1763 1764 remap_and_issue_shared_cell(tc, data_cell, lookup_result->block); 1765 remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block); 1766 } 1767 } 1768 1769 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block, 1770 struct dm_bio_prison_cell *cell) 1771 { 1772 int r; 1773 dm_block_t data_block; 1774 struct pool *pool = tc->pool; 1775 1776 /* 1777 * Remap empty bios (flushes) immediately, without provisioning. 1778 */ 1779 if (!bio->bi_iter.bi_size) { 1780 inc_all_io_entry(pool, bio); 1781 cell_defer_no_holder(tc, cell); 1782 1783 remap_and_issue(tc, bio, 0); 1784 return; 1785 } 1786 1787 /* 1788 * Fill read bios with zeroes and complete them immediately. 1789 */ 1790 if (bio_data_dir(bio) == READ) { 1791 zero_fill_bio(bio); 1792 cell_defer_no_holder(tc, cell); 1793 bio_endio(bio, 0); 1794 return; 1795 } 1796 1797 r = alloc_data_block(tc, &data_block); 1798 switch (r) { 1799 case 0: 1800 if (tc->origin_dev) 1801 schedule_external_copy(tc, block, data_block, cell, bio); 1802 else 1803 schedule_zero(tc, block, data_block, cell, bio); 1804 break; 1805 1806 case -ENOSPC: 1807 retry_bios_on_resume(pool, cell); 1808 break; 1809 1810 default: 1811 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d", 1812 __func__, r); 1813 cell_error(pool, cell); 1814 break; 1815 } 1816 } 1817 1818 static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) 1819 { 1820 int r; 1821 struct pool *pool = tc->pool; 1822 struct bio *bio = cell->holder; 1823 dm_block_t block = get_bio_block(tc, bio); 1824 struct dm_thin_lookup_result lookup_result; 1825 1826 if (tc->requeue_mode) { 1827 cell_requeue(pool, cell); 1828 return; 1829 } 1830 1831 r = dm_thin_find_block(tc->td, block, 1, &lookup_result); 1832 switch (r) { 1833 case 0: 1834 if (lookup_result.shared) 1835 process_shared_bio(tc, bio, block, &lookup_result, cell); 1836 else { 1837 inc_all_io_entry(pool, bio); 1838 remap_and_issue(tc, bio, lookup_result.block); 1839 inc_remap_and_issue_cell(tc, cell, lookup_result.block); 1840 } 1841 break; 1842 1843 case -ENODATA: 1844 if (bio_data_dir(bio) == READ && tc->origin_dev) { 1845 inc_all_io_entry(pool, bio); 1846 cell_defer_no_holder(tc, cell); 1847 1848 if (bio_end_sector(bio) <= tc->origin_size) 1849 remap_to_origin_and_issue(tc, bio); 1850 1851 else if (bio->bi_iter.bi_sector < tc->origin_size) { 1852 zero_fill_bio(bio); 1853 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT; 1854 remap_to_origin_and_issue(tc, bio); 1855 1856 } else { 1857 zero_fill_bio(bio); 1858 bio_endio(bio, 0); 1859 } 1860 } else 1861 provision_block(tc, bio, block, cell); 1862 break; 1863 1864 default: 1865 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d", 1866 __func__, r); 1867 cell_defer_no_holder(tc, cell); 1868 bio_io_error(bio); 1869 break; 1870 } 1871 } 1872 1873 static void process_bio(struct thin_c *tc, struct bio *bio) 1874 { 1875 struct pool *pool = tc->pool; 1876 dm_block_t block = get_bio_block(tc, bio); 1877 struct dm_bio_prison_cell *cell; 1878 struct dm_cell_key key; 1879 1880 /* 1881 * If cell is already occupied, then the block is already 1882 * being provisioned so we have nothing further to do here. 1883 */ 1884 build_virtual_key(tc->td, block, &key); 1885 if (bio_detain(pool, &key, bio, &cell)) 1886 return; 1887 1888 process_cell(tc, cell); 1889 } 1890 1891 static void __process_bio_read_only(struct thin_c *tc, struct bio *bio, 1892 struct dm_bio_prison_cell *cell) 1893 { 1894 int r; 1895 int rw = bio_data_dir(bio); 1896 dm_block_t block = get_bio_block(tc, bio); 1897 struct dm_thin_lookup_result lookup_result; 1898 1899 r = dm_thin_find_block(tc->td, block, 1, &lookup_result); 1900 switch (r) { 1901 case 0: 1902 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) { 1903 handle_unserviceable_bio(tc->pool, bio); 1904 if (cell) 1905 cell_defer_no_holder(tc, cell); 1906 } else { 1907 inc_all_io_entry(tc->pool, bio); 1908 remap_and_issue(tc, bio, lookup_result.block); 1909 if (cell) 1910 inc_remap_and_issue_cell(tc, cell, lookup_result.block); 1911 } 1912 break; 1913 1914 case -ENODATA: 1915 if (cell) 1916 cell_defer_no_holder(tc, cell); 1917 if (rw != READ) { 1918 handle_unserviceable_bio(tc->pool, bio); 1919 break; 1920 } 1921 1922 if (tc->origin_dev) { 1923 inc_all_io_entry(tc->pool, bio); 1924 remap_to_origin_and_issue(tc, bio); 1925 break; 1926 } 1927 1928 zero_fill_bio(bio); 1929 bio_endio(bio, 0); 1930 break; 1931 1932 default: 1933 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d", 1934 __func__, r); 1935 if (cell) 1936 cell_defer_no_holder(tc, cell); 1937 bio_io_error(bio); 1938 break; 1939 } 1940 } 1941 1942 static void process_bio_read_only(struct thin_c *tc, struct bio *bio) 1943 { 1944 __process_bio_read_only(tc, bio, NULL); 1945 } 1946 1947 static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell) 1948 { 1949 __process_bio_read_only(tc, cell->holder, cell); 1950 } 1951 1952 static void process_bio_success(struct thin_c *tc, struct bio *bio) 1953 { 1954 bio_endio(bio, 0); 1955 } 1956 1957 static void process_bio_fail(struct thin_c *tc, struct bio *bio) 1958 { 1959 bio_io_error(bio); 1960 } 1961 1962 static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell) 1963 { 1964 cell_success(tc->pool, cell); 1965 } 1966 1967 static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell) 1968 { 1969 cell_error(tc->pool, cell); 1970 } 1971 1972 /* 1973 * FIXME: should we also commit due to size of transaction, measured in 1974 * metadata blocks? 1975 */ 1976 static int need_commit_due_to_time(struct pool *pool) 1977 { 1978 return !time_in_range(jiffies, pool->last_commit_jiffies, 1979 pool->last_commit_jiffies + COMMIT_PERIOD); 1980 } 1981 1982 #define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node) 1983 #define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook)) 1984 1985 static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio) 1986 { 1987 struct rb_node **rbp, *parent; 1988 struct dm_thin_endio_hook *pbd; 1989 sector_t bi_sector = bio->bi_iter.bi_sector; 1990 1991 rbp = &tc->sort_bio_list.rb_node; 1992 parent = NULL; 1993 while (*rbp) { 1994 parent = *rbp; 1995 pbd = thin_pbd(parent); 1996 1997 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector) 1998 rbp = &(*rbp)->rb_left; 1999 else 2000 rbp = &(*rbp)->rb_right; 2001 } 2002 2003 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 2004 rb_link_node(&pbd->rb_node, parent, rbp); 2005 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list); 2006 } 2007 2008 static void __extract_sorted_bios(struct thin_c *tc) 2009 { 2010 struct rb_node *node; 2011 struct dm_thin_endio_hook *pbd; 2012 struct bio *bio; 2013 2014 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) { 2015 pbd = thin_pbd(node); 2016 bio = thin_bio(pbd); 2017 2018 bio_list_add(&tc->deferred_bio_list, bio); 2019 rb_erase(&pbd->rb_node, &tc->sort_bio_list); 2020 } 2021 2022 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list)); 2023 } 2024 2025 static void __sort_thin_deferred_bios(struct thin_c *tc) 2026 { 2027 struct bio *bio; 2028 struct bio_list bios; 2029 2030 bio_list_init(&bios); 2031 bio_list_merge(&bios, &tc->deferred_bio_list); 2032 bio_list_init(&tc->deferred_bio_list); 2033 2034 /* Sort deferred_bio_list using rb-tree */ 2035 while ((bio = bio_list_pop(&bios))) 2036 __thin_bio_rb_add(tc, bio); 2037 2038 /* 2039 * Transfer the sorted bios in sort_bio_list back to 2040 * deferred_bio_list to allow lockless submission of 2041 * all bios. 2042 */ 2043 __extract_sorted_bios(tc); 2044 } 2045 2046 static void process_thin_deferred_bios(struct thin_c *tc) 2047 { 2048 struct pool *pool = tc->pool; 2049 unsigned long flags; 2050 struct bio *bio; 2051 struct bio_list bios; 2052 struct blk_plug plug; 2053 unsigned count = 0; 2054 2055 if (tc->requeue_mode) { 2056 error_thin_bio_list(tc, &tc->deferred_bio_list, DM_ENDIO_REQUEUE); 2057 return; 2058 } 2059 2060 bio_list_init(&bios); 2061 2062 spin_lock_irqsave(&tc->lock, flags); 2063 2064 if (bio_list_empty(&tc->deferred_bio_list)) { 2065 spin_unlock_irqrestore(&tc->lock, flags); 2066 return; 2067 } 2068 2069 __sort_thin_deferred_bios(tc); 2070 2071 bio_list_merge(&bios, &tc->deferred_bio_list); 2072 bio_list_init(&tc->deferred_bio_list); 2073 2074 spin_unlock_irqrestore(&tc->lock, flags); 2075 2076 blk_start_plug(&plug); 2077 while ((bio = bio_list_pop(&bios))) { 2078 /* 2079 * If we've got no free new_mapping structs, and processing 2080 * this bio might require one, we pause until there are some 2081 * prepared mappings to process. 2082 */ 2083 if (ensure_next_mapping(pool)) { 2084 spin_lock_irqsave(&tc->lock, flags); 2085 bio_list_add(&tc->deferred_bio_list, bio); 2086 bio_list_merge(&tc->deferred_bio_list, &bios); 2087 spin_unlock_irqrestore(&tc->lock, flags); 2088 break; 2089 } 2090 2091 if (bio->bi_rw & REQ_DISCARD) 2092 pool->process_discard(tc, bio); 2093 else 2094 pool->process_bio(tc, bio); 2095 2096 if ((count++ & 127) == 0) { 2097 throttle_work_update(&pool->throttle); 2098 dm_pool_issue_prefetches(pool->pmd); 2099 } 2100 } 2101 blk_finish_plug(&plug); 2102 } 2103 2104 static int cmp_cells(const void *lhs, const void *rhs) 2105 { 2106 struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs); 2107 struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs); 2108 2109 BUG_ON(!lhs_cell->holder); 2110 BUG_ON(!rhs_cell->holder); 2111 2112 if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector) 2113 return -1; 2114 2115 if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector) 2116 return 1; 2117 2118 return 0; 2119 } 2120 2121 static unsigned sort_cells(struct pool *pool, struct list_head *cells) 2122 { 2123 unsigned count = 0; 2124 struct dm_bio_prison_cell *cell, *tmp; 2125 2126 list_for_each_entry_safe(cell, tmp, cells, user_list) { 2127 if (count >= CELL_SORT_ARRAY_SIZE) 2128 break; 2129 2130 pool->cell_sort_array[count++] = cell; 2131 list_del(&cell->user_list); 2132 } 2133 2134 sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL); 2135 2136 return count; 2137 } 2138 2139 static void process_thin_deferred_cells(struct thin_c *tc) 2140 { 2141 struct pool *pool = tc->pool; 2142 unsigned long flags; 2143 struct list_head cells; 2144 struct dm_bio_prison_cell *cell; 2145 unsigned i, j, count; 2146 2147 INIT_LIST_HEAD(&cells); 2148 2149 spin_lock_irqsave(&tc->lock, flags); 2150 list_splice_init(&tc->deferred_cells, &cells); 2151 spin_unlock_irqrestore(&tc->lock, flags); 2152 2153 if (list_empty(&cells)) 2154 return; 2155 2156 do { 2157 count = sort_cells(tc->pool, &cells); 2158 2159 for (i = 0; i < count; i++) { 2160 cell = pool->cell_sort_array[i]; 2161 BUG_ON(!cell->holder); 2162 2163 /* 2164 * If we've got no free new_mapping structs, and processing 2165 * this bio might require one, we pause until there are some 2166 * prepared mappings to process. 2167 */ 2168 if (ensure_next_mapping(pool)) { 2169 for (j = i; j < count; j++) 2170 list_add(&pool->cell_sort_array[j]->user_list, &cells); 2171 2172 spin_lock_irqsave(&tc->lock, flags); 2173 list_splice(&cells, &tc->deferred_cells); 2174 spin_unlock_irqrestore(&tc->lock, flags); 2175 return; 2176 } 2177 2178 if (cell->holder->bi_rw & REQ_DISCARD) 2179 pool->process_discard_cell(tc, cell); 2180 else 2181 pool->process_cell(tc, cell); 2182 } 2183 } while (!list_empty(&cells)); 2184 } 2185 2186 static void thin_get(struct thin_c *tc); 2187 static void thin_put(struct thin_c *tc); 2188 2189 /* 2190 * We can't hold rcu_read_lock() around code that can block. So we 2191 * find a thin with the rcu lock held; bump a refcount; then drop 2192 * the lock. 2193 */ 2194 static struct thin_c *get_first_thin(struct pool *pool) 2195 { 2196 struct thin_c *tc = NULL; 2197 2198 rcu_read_lock(); 2199 if (!list_empty(&pool->active_thins)) { 2200 tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list); 2201 thin_get(tc); 2202 } 2203 rcu_read_unlock(); 2204 2205 return tc; 2206 } 2207 2208 static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc) 2209 { 2210 struct thin_c *old_tc = tc; 2211 2212 rcu_read_lock(); 2213 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) { 2214 thin_get(tc); 2215 thin_put(old_tc); 2216 rcu_read_unlock(); 2217 return tc; 2218 } 2219 thin_put(old_tc); 2220 rcu_read_unlock(); 2221 2222 return NULL; 2223 } 2224 2225 static void process_deferred_bios(struct pool *pool) 2226 { 2227 unsigned long flags; 2228 struct bio *bio; 2229 struct bio_list bios; 2230 struct thin_c *tc; 2231 2232 tc = get_first_thin(pool); 2233 while (tc) { 2234 process_thin_deferred_cells(tc); 2235 process_thin_deferred_bios(tc); 2236 tc = get_next_thin(pool, tc); 2237 } 2238 2239 /* 2240 * If there are any deferred flush bios, we must commit 2241 * the metadata before issuing them. 2242 */ 2243 bio_list_init(&bios); 2244 spin_lock_irqsave(&pool->lock, flags); 2245 bio_list_merge(&bios, &pool->deferred_flush_bios); 2246 bio_list_init(&pool->deferred_flush_bios); 2247 spin_unlock_irqrestore(&pool->lock, flags); 2248 2249 if (bio_list_empty(&bios) && 2250 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool))) 2251 return; 2252 2253 if (commit(pool)) { 2254 while ((bio = bio_list_pop(&bios))) 2255 bio_io_error(bio); 2256 return; 2257 } 2258 pool->last_commit_jiffies = jiffies; 2259 2260 while ((bio = bio_list_pop(&bios))) 2261 generic_make_request(bio); 2262 } 2263 2264 static void do_worker(struct work_struct *ws) 2265 { 2266 struct pool *pool = container_of(ws, struct pool, worker); 2267 2268 throttle_work_start(&pool->throttle); 2269 dm_pool_issue_prefetches(pool->pmd); 2270 throttle_work_update(&pool->throttle); 2271 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping); 2272 throttle_work_update(&pool->throttle); 2273 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard); 2274 throttle_work_update(&pool->throttle); 2275 process_deferred_bios(pool); 2276 throttle_work_complete(&pool->throttle); 2277 } 2278 2279 /* 2280 * We want to commit periodically so that not too much 2281 * unwritten data builds up. 2282 */ 2283 static void do_waker(struct work_struct *ws) 2284 { 2285 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker); 2286 wake_worker(pool); 2287 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD); 2288 } 2289 2290 static void notify_of_pool_mode_change_to_oods(struct pool *pool); 2291 2292 /* 2293 * We're holding onto IO to allow userland time to react. After the 2294 * timeout either the pool will have been resized (and thus back in 2295 * PM_WRITE mode), or we degrade to PM_OUT_OF_DATA_SPACE w/ error_if_no_space. 2296 */ 2297 static void do_no_space_timeout(struct work_struct *ws) 2298 { 2299 struct pool *pool = container_of(to_delayed_work(ws), struct pool, 2300 no_space_timeout); 2301 2302 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) { 2303 pool->pf.error_if_no_space = true; 2304 notify_of_pool_mode_change_to_oods(pool); 2305 error_retry_list_with_code(pool, -ENOSPC); 2306 } 2307 } 2308 2309 /*----------------------------------------------------------------*/ 2310 2311 struct pool_work { 2312 struct work_struct worker; 2313 struct completion complete; 2314 }; 2315 2316 static struct pool_work *to_pool_work(struct work_struct *ws) 2317 { 2318 return container_of(ws, struct pool_work, worker); 2319 } 2320 2321 static void pool_work_complete(struct pool_work *pw) 2322 { 2323 complete(&pw->complete); 2324 } 2325 2326 static void pool_work_wait(struct pool_work *pw, struct pool *pool, 2327 void (*fn)(struct work_struct *)) 2328 { 2329 INIT_WORK_ONSTACK(&pw->worker, fn); 2330 init_completion(&pw->complete); 2331 queue_work(pool->wq, &pw->worker); 2332 wait_for_completion(&pw->complete); 2333 } 2334 2335 /*----------------------------------------------------------------*/ 2336 2337 struct noflush_work { 2338 struct pool_work pw; 2339 struct thin_c *tc; 2340 }; 2341 2342 static struct noflush_work *to_noflush(struct work_struct *ws) 2343 { 2344 return container_of(to_pool_work(ws), struct noflush_work, pw); 2345 } 2346 2347 static void do_noflush_start(struct work_struct *ws) 2348 { 2349 struct noflush_work *w = to_noflush(ws); 2350 w->tc->requeue_mode = true; 2351 requeue_io(w->tc); 2352 pool_work_complete(&w->pw); 2353 } 2354 2355 static void do_noflush_stop(struct work_struct *ws) 2356 { 2357 struct noflush_work *w = to_noflush(ws); 2358 w->tc->requeue_mode = false; 2359 pool_work_complete(&w->pw); 2360 } 2361 2362 static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *)) 2363 { 2364 struct noflush_work w; 2365 2366 w.tc = tc; 2367 pool_work_wait(&w.pw, tc->pool, fn); 2368 } 2369 2370 /*----------------------------------------------------------------*/ 2371 2372 static enum pool_mode get_pool_mode(struct pool *pool) 2373 { 2374 return pool->pf.mode; 2375 } 2376 2377 static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode) 2378 { 2379 dm_table_event(pool->ti->table); 2380 DMINFO("%s: switching pool to %s mode", 2381 dm_device_name(pool->pool_md), new_mode); 2382 } 2383 2384 static void notify_of_pool_mode_change_to_oods(struct pool *pool) 2385 { 2386 if (!pool->pf.error_if_no_space) 2387 notify_of_pool_mode_change(pool, "out-of-data-space (queue IO)"); 2388 else 2389 notify_of_pool_mode_change(pool, "out-of-data-space (error IO)"); 2390 } 2391 2392 static bool passdown_enabled(struct pool_c *pt) 2393 { 2394 return pt->adjusted_pf.discard_passdown; 2395 } 2396 2397 static void set_discard_callbacks(struct pool *pool) 2398 { 2399 struct pool_c *pt = pool->ti->private; 2400 2401 if (passdown_enabled(pt)) { 2402 pool->process_discard_cell = process_discard_cell_passdown; 2403 pool->process_prepared_discard = process_prepared_discard_passdown; 2404 } else { 2405 pool->process_discard_cell = process_discard_cell_no_passdown; 2406 pool->process_prepared_discard = process_prepared_discard_no_passdown; 2407 } 2408 } 2409 2410 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode) 2411 { 2412 struct pool_c *pt = pool->ti->private; 2413 bool needs_check = dm_pool_metadata_needs_check(pool->pmd); 2414 enum pool_mode old_mode = get_pool_mode(pool); 2415 unsigned long no_space_timeout = ACCESS_ONCE(no_space_timeout_secs) * HZ; 2416 2417 /* 2418 * Never allow the pool to transition to PM_WRITE mode if user 2419 * intervention is required to verify metadata and data consistency. 2420 */ 2421 if (new_mode == PM_WRITE && needs_check) { 2422 DMERR("%s: unable to switch pool to write mode until repaired.", 2423 dm_device_name(pool->pool_md)); 2424 if (old_mode != new_mode) 2425 new_mode = old_mode; 2426 else 2427 new_mode = PM_READ_ONLY; 2428 } 2429 /* 2430 * If we were in PM_FAIL mode, rollback of metadata failed. We're 2431 * not going to recover without a thin_repair. So we never let the 2432 * pool move out of the old mode. 2433 */ 2434 if (old_mode == PM_FAIL) 2435 new_mode = old_mode; 2436 2437 switch (new_mode) { 2438 case PM_FAIL: 2439 if (old_mode != new_mode) 2440 notify_of_pool_mode_change(pool, "failure"); 2441 dm_pool_metadata_read_only(pool->pmd); 2442 pool->process_bio = process_bio_fail; 2443 pool->process_discard = process_bio_fail; 2444 pool->process_cell = process_cell_fail; 2445 pool->process_discard_cell = process_cell_fail; 2446 pool->process_prepared_mapping = process_prepared_mapping_fail; 2447 pool->process_prepared_discard = process_prepared_discard_fail; 2448 2449 error_retry_list(pool); 2450 break; 2451 2452 case PM_READ_ONLY: 2453 if (old_mode != new_mode) 2454 notify_of_pool_mode_change(pool, "read-only"); 2455 dm_pool_metadata_read_only(pool->pmd); 2456 pool->process_bio = process_bio_read_only; 2457 pool->process_discard = process_bio_success; 2458 pool->process_cell = process_cell_read_only; 2459 pool->process_discard_cell = process_cell_success; 2460 pool->process_prepared_mapping = process_prepared_mapping_fail; 2461 pool->process_prepared_discard = process_prepared_discard_success; 2462 2463 error_retry_list(pool); 2464 break; 2465 2466 case PM_OUT_OF_DATA_SPACE: 2467 /* 2468 * Ideally we'd never hit this state; the low water mark 2469 * would trigger userland to extend the pool before we 2470 * completely run out of data space. However, many small 2471 * IOs to unprovisioned space can consume data space at an 2472 * alarming rate. Adjust your low water mark if you're 2473 * frequently seeing this mode. 2474 */ 2475 if (old_mode != new_mode) 2476 notify_of_pool_mode_change_to_oods(pool); 2477 pool->process_bio = process_bio_read_only; 2478 pool->process_discard = process_discard_bio; 2479 pool->process_cell = process_cell_read_only; 2480 pool->process_prepared_mapping = process_prepared_mapping; 2481 set_discard_callbacks(pool); 2482 2483 if (!pool->pf.error_if_no_space && no_space_timeout) 2484 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout); 2485 break; 2486 2487 case PM_WRITE: 2488 if (old_mode != new_mode) 2489 notify_of_pool_mode_change(pool, "write"); 2490 dm_pool_metadata_read_write(pool->pmd); 2491 pool->process_bio = process_bio; 2492 pool->process_discard = process_discard_bio; 2493 pool->process_cell = process_cell; 2494 pool->process_prepared_mapping = process_prepared_mapping; 2495 set_discard_callbacks(pool); 2496 break; 2497 } 2498 2499 pool->pf.mode = new_mode; 2500 /* 2501 * The pool mode may have changed, sync it so bind_control_target() 2502 * doesn't cause an unexpected mode transition on resume. 2503 */ 2504 pt->adjusted_pf.mode = new_mode; 2505 } 2506 2507 static void abort_transaction(struct pool *pool) 2508 { 2509 const char *dev_name = dm_device_name(pool->pool_md); 2510 2511 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name); 2512 if (dm_pool_abort_metadata(pool->pmd)) { 2513 DMERR("%s: failed to abort metadata transaction", dev_name); 2514 set_pool_mode(pool, PM_FAIL); 2515 } 2516 2517 if (dm_pool_metadata_set_needs_check(pool->pmd)) { 2518 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name); 2519 set_pool_mode(pool, PM_FAIL); 2520 } 2521 } 2522 2523 static void metadata_operation_failed(struct pool *pool, const char *op, int r) 2524 { 2525 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d", 2526 dm_device_name(pool->pool_md), op, r); 2527 2528 abort_transaction(pool); 2529 set_pool_mode(pool, PM_READ_ONLY); 2530 } 2531 2532 /*----------------------------------------------------------------*/ 2533 2534 /* 2535 * Mapping functions. 2536 */ 2537 2538 /* 2539 * Called only while mapping a thin bio to hand it over to the workqueue. 2540 */ 2541 static void thin_defer_bio(struct thin_c *tc, struct bio *bio) 2542 { 2543 unsigned long flags; 2544 struct pool *pool = tc->pool; 2545 2546 spin_lock_irqsave(&tc->lock, flags); 2547 bio_list_add(&tc->deferred_bio_list, bio); 2548 spin_unlock_irqrestore(&tc->lock, flags); 2549 2550 wake_worker(pool); 2551 } 2552 2553 static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio) 2554 { 2555 struct pool *pool = tc->pool; 2556 2557 throttle_lock(&pool->throttle); 2558 thin_defer_bio(tc, bio); 2559 throttle_unlock(&pool->throttle); 2560 } 2561 2562 static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) 2563 { 2564 unsigned long flags; 2565 struct pool *pool = tc->pool; 2566 2567 throttle_lock(&pool->throttle); 2568 spin_lock_irqsave(&tc->lock, flags); 2569 list_add_tail(&cell->user_list, &tc->deferred_cells); 2570 spin_unlock_irqrestore(&tc->lock, flags); 2571 throttle_unlock(&pool->throttle); 2572 2573 wake_worker(pool); 2574 } 2575 2576 static void thin_hook_bio(struct thin_c *tc, struct bio *bio) 2577 { 2578 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 2579 2580 h->tc = tc; 2581 h->shared_read_entry = NULL; 2582 h->all_io_entry = NULL; 2583 h->overwrite_mapping = NULL; 2584 h->cell = NULL; 2585 } 2586 2587 /* 2588 * Non-blocking function called from the thin target's map function. 2589 */ 2590 static int thin_bio_map(struct dm_target *ti, struct bio *bio) 2591 { 2592 int r; 2593 struct thin_c *tc = ti->private; 2594 dm_block_t block = get_bio_block(tc, bio); 2595 struct dm_thin_device *td = tc->td; 2596 struct dm_thin_lookup_result result; 2597 struct dm_bio_prison_cell *virt_cell, *data_cell; 2598 struct dm_cell_key key; 2599 2600 thin_hook_bio(tc, bio); 2601 2602 if (tc->requeue_mode) { 2603 bio_endio(bio, DM_ENDIO_REQUEUE); 2604 return DM_MAPIO_SUBMITTED; 2605 } 2606 2607 if (get_pool_mode(tc->pool) == PM_FAIL) { 2608 bio_io_error(bio); 2609 return DM_MAPIO_SUBMITTED; 2610 } 2611 2612 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) { 2613 thin_defer_bio_with_throttle(tc, bio); 2614 return DM_MAPIO_SUBMITTED; 2615 } 2616 2617 /* 2618 * We must hold the virtual cell before doing the lookup, otherwise 2619 * there's a race with discard. 2620 */ 2621 build_virtual_key(tc->td, block, &key); 2622 if (bio_detain(tc->pool, &key, bio, &virt_cell)) 2623 return DM_MAPIO_SUBMITTED; 2624 2625 r = dm_thin_find_block(td, block, 0, &result); 2626 2627 /* 2628 * Note that we defer readahead too. 2629 */ 2630 switch (r) { 2631 case 0: 2632 if (unlikely(result.shared)) { 2633 /* 2634 * We have a race condition here between the 2635 * result.shared value returned by the lookup and 2636 * snapshot creation, which may cause new 2637 * sharing. 2638 * 2639 * To avoid this always quiesce the origin before 2640 * taking the snap. You want to do this anyway to 2641 * ensure a consistent application view 2642 * (i.e. lockfs). 2643 * 2644 * More distant ancestors are irrelevant. The 2645 * shared flag will be set in their case. 2646 */ 2647 thin_defer_cell(tc, virt_cell); 2648 return DM_MAPIO_SUBMITTED; 2649 } 2650 2651 build_data_key(tc->td, result.block, &key); 2652 if (bio_detain(tc->pool, &key, bio, &data_cell)) { 2653 cell_defer_no_holder(tc, virt_cell); 2654 return DM_MAPIO_SUBMITTED; 2655 } 2656 2657 inc_all_io_entry(tc->pool, bio); 2658 cell_defer_no_holder(tc, data_cell); 2659 cell_defer_no_holder(tc, virt_cell); 2660 2661 remap(tc, bio, result.block); 2662 return DM_MAPIO_REMAPPED; 2663 2664 case -ENODATA: 2665 case -EWOULDBLOCK: 2666 thin_defer_cell(tc, virt_cell); 2667 return DM_MAPIO_SUBMITTED; 2668 2669 default: 2670 /* 2671 * Must always call bio_io_error on failure. 2672 * dm_thin_find_block can fail with -EINVAL if the 2673 * pool is switched to fail-io mode. 2674 */ 2675 bio_io_error(bio); 2676 cell_defer_no_holder(tc, virt_cell); 2677 return DM_MAPIO_SUBMITTED; 2678 } 2679 } 2680 2681 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits) 2682 { 2683 struct pool_c *pt = container_of(cb, struct pool_c, callbacks); 2684 struct request_queue *q; 2685 2686 if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE) 2687 return 1; 2688 2689 q = bdev_get_queue(pt->data_dev->bdev); 2690 return bdi_congested(&q->backing_dev_info, bdi_bits); 2691 } 2692 2693 static void requeue_bios(struct pool *pool) 2694 { 2695 unsigned long flags; 2696 struct thin_c *tc; 2697 2698 rcu_read_lock(); 2699 list_for_each_entry_rcu(tc, &pool->active_thins, list) { 2700 spin_lock_irqsave(&tc->lock, flags); 2701 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list); 2702 bio_list_init(&tc->retry_on_resume_list); 2703 spin_unlock_irqrestore(&tc->lock, flags); 2704 } 2705 rcu_read_unlock(); 2706 } 2707 2708 /*---------------------------------------------------------------- 2709 * Binding of control targets to a pool object 2710 *--------------------------------------------------------------*/ 2711 static bool data_dev_supports_discard(struct pool_c *pt) 2712 { 2713 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); 2714 2715 return q && blk_queue_discard(q); 2716 } 2717 2718 static bool is_factor(sector_t block_size, uint32_t n) 2719 { 2720 return !sector_div(block_size, n); 2721 } 2722 2723 /* 2724 * If discard_passdown was enabled verify that the data device 2725 * supports discards. Disable discard_passdown if not. 2726 */ 2727 static void disable_passdown_if_not_supported(struct pool_c *pt) 2728 { 2729 struct pool *pool = pt->pool; 2730 struct block_device *data_bdev = pt->data_dev->bdev; 2731 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits; 2732 const char *reason = NULL; 2733 char buf[BDEVNAME_SIZE]; 2734 2735 if (!pt->adjusted_pf.discard_passdown) 2736 return; 2737 2738 if (!data_dev_supports_discard(pt)) 2739 reason = "discard unsupported"; 2740 2741 else if (data_limits->max_discard_sectors < pool->sectors_per_block) 2742 reason = "max discard sectors smaller than a block"; 2743 2744 if (reason) { 2745 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason); 2746 pt->adjusted_pf.discard_passdown = false; 2747 } 2748 } 2749 2750 static int bind_control_target(struct pool *pool, struct dm_target *ti) 2751 { 2752 struct pool_c *pt = ti->private; 2753 2754 /* 2755 * We want to make sure that a pool in PM_FAIL mode is never upgraded. 2756 */ 2757 enum pool_mode old_mode = get_pool_mode(pool); 2758 enum pool_mode new_mode = pt->adjusted_pf.mode; 2759 2760 /* 2761 * Don't change the pool's mode until set_pool_mode() below. 2762 * Otherwise the pool's process_* function pointers may 2763 * not match the desired pool mode. 2764 */ 2765 pt->adjusted_pf.mode = old_mode; 2766 2767 pool->ti = ti; 2768 pool->pf = pt->adjusted_pf; 2769 pool->low_water_blocks = pt->low_water_blocks; 2770 2771 set_pool_mode(pool, new_mode); 2772 2773 return 0; 2774 } 2775 2776 static void unbind_control_target(struct pool *pool, struct dm_target *ti) 2777 { 2778 if (pool->ti == ti) 2779 pool->ti = NULL; 2780 } 2781 2782 /*---------------------------------------------------------------- 2783 * Pool creation 2784 *--------------------------------------------------------------*/ 2785 /* Initialize pool features. */ 2786 static void pool_features_init(struct pool_features *pf) 2787 { 2788 pf->mode = PM_WRITE; 2789 pf->zero_new_blocks = true; 2790 pf->discard_enabled = true; 2791 pf->discard_passdown = true; 2792 pf->error_if_no_space = false; 2793 } 2794 2795 static void __pool_destroy(struct pool *pool) 2796 { 2797 __pool_table_remove(pool); 2798 2799 vfree(pool->cell_sort_array); 2800 if (dm_pool_metadata_close(pool->pmd) < 0) 2801 DMWARN("%s: dm_pool_metadata_close() failed.", __func__); 2802 2803 dm_bio_prison_destroy(pool->prison); 2804 dm_kcopyd_client_destroy(pool->copier); 2805 2806 if (pool->wq) 2807 destroy_workqueue(pool->wq); 2808 2809 if (pool->next_mapping) 2810 mempool_free(pool->next_mapping, pool->mapping_pool); 2811 mempool_destroy(pool->mapping_pool); 2812 dm_deferred_set_destroy(pool->shared_read_ds); 2813 dm_deferred_set_destroy(pool->all_io_ds); 2814 kfree(pool); 2815 } 2816 2817 static struct kmem_cache *_new_mapping_cache; 2818 2819 static struct pool *pool_create(struct mapped_device *pool_md, 2820 struct block_device *metadata_dev, 2821 unsigned long block_size, 2822 int read_only, char **error) 2823 { 2824 int r; 2825 void *err_p; 2826 struct pool *pool; 2827 struct dm_pool_metadata *pmd; 2828 bool format_device = read_only ? false : true; 2829 2830 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device); 2831 if (IS_ERR(pmd)) { 2832 *error = "Error creating metadata object"; 2833 return (struct pool *)pmd; 2834 } 2835 2836 pool = kmalloc(sizeof(*pool), GFP_KERNEL); 2837 if (!pool) { 2838 *error = "Error allocating memory for pool"; 2839 err_p = ERR_PTR(-ENOMEM); 2840 goto bad_pool; 2841 } 2842 2843 pool->pmd = pmd; 2844 pool->sectors_per_block = block_size; 2845 if (block_size & (block_size - 1)) 2846 pool->sectors_per_block_shift = -1; 2847 else 2848 pool->sectors_per_block_shift = __ffs(block_size); 2849 pool->low_water_blocks = 0; 2850 pool_features_init(&pool->pf); 2851 pool->prison = dm_bio_prison_create(); 2852 if (!pool->prison) { 2853 *error = "Error creating pool's bio prison"; 2854 err_p = ERR_PTR(-ENOMEM); 2855 goto bad_prison; 2856 } 2857 2858 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); 2859 if (IS_ERR(pool->copier)) { 2860 r = PTR_ERR(pool->copier); 2861 *error = "Error creating pool's kcopyd client"; 2862 err_p = ERR_PTR(r); 2863 goto bad_kcopyd_client; 2864 } 2865 2866 /* 2867 * Create singlethreaded workqueue that will service all devices 2868 * that use this metadata. 2869 */ 2870 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); 2871 if (!pool->wq) { 2872 *error = "Error creating pool's workqueue"; 2873 err_p = ERR_PTR(-ENOMEM); 2874 goto bad_wq; 2875 } 2876 2877 throttle_init(&pool->throttle); 2878 INIT_WORK(&pool->worker, do_worker); 2879 INIT_DELAYED_WORK(&pool->waker, do_waker); 2880 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout); 2881 spin_lock_init(&pool->lock); 2882 bio_list_init(&pool->deferred_flush_bios); 2883 INIT_LIST_HEAD(&pool->prepared_mappings); 2884 INIT_LIST_HEAD(&pool->prepared_discards); 2885 INIT_LIST_HEAD(&pool->active_thins); 2886 pool->low_water_triggered = false; 2887 pool->suspended = true; 2888 2889 pool->shared_read_ds = dm_deferred_set_create(); 2890 if (!pool->shared_read_ds) { 2891 *error = "Error creating pool's shared read deferred set"; 2892 err_p = ERR_PTR(-ENOMEM); 2893 goto bad_shared_read_ds; 2894 } 2895 2896 pool->all_io_ds = dm_deferred_set_create(); 2897 if (!pool->all_io_ds) { 2898 *error = "Error creating pool's all io deferred set"; 2899 err_p = ERR_PTR(-ENOMEM); 2900 goto bad_all_io_ds; 2901 } 2902 2903 pool->next_mapping = NULL; 2904 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE, 2905 _new_mapping_cache); 2906 if (!pool->mapping_pool) { 2907 *error = "Error creating pool's mapping mempool"; 2908 err_p = ERR_PTR(-ENOMEM); 2909 goto bad_mapping_pool; 2910 } 2911 2912 pool->cell_sort_array = vmalloc(sizeof(*pool->cell_sort_array) * CELL_SORT_ARRAY_SIZE); 2913 if (!pool->cell_sort_array) { 2914 *error = "Error allocating cell sort array"; 2915 err_p = ERR_PTR(-ENOMEM); 2916 goto bad_sort_array; 2917 } 2918 2919 pool->ref_count = 1; 2920 pool->last_commit_jiffies = jiffies; 2921 pool->pool_md = pool_md; 2922 pool->md_dev = metadata_dev; 2923 __pool_table_insert(pool); 2924 2925 return pool; 2926 2927 bad_sort_array: 2928 mempool_destroy(pool->mapping_pool); 2929 bad_mapping_pool: 2930 dm_deferred_set_destroy(pool->all_io_ds); 2931 bad_all_io_ds: 2932 dm_deferred_set_destroy(pool->shared_read_ds); 2933 bad_shared_read_ds: 2934 destroy_workqueue(pool->wq); 2935 bad_wq: 2936 dm_kcopyd_client_destroy(pool->copier); 2937 bad_kcopyd_client: 2938 dm_bio_prison_destroy(pool->prison); 2939 bad_prison: 2940 kfree(pool); 2941 bad_pool: 2942 if (dm_pool_metadata_close(pmd)) 2943 DMWARN("%s: dm_pool_metadata_close() failed.", __func__); 2944 2945 return err_p; 2946 } 2947 2948 static void __pool_inc(struct pool *pool) 2949 { 2950 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); 2951 pool->ref_count++; 2952 } 2953 2954 static void __pool_dec(struct pool *pool) 2955 { 2956 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); 2957 BUG_ON(!pool->ref_count); 2958 if (!--pool->ref_count) 2959 __pool_destroy(pool); 2960 } 2961 2962 static struct pool *__pool_find(struct mapped_device *pool_md, 2963 struct block_device *metadata_dev, 2964 unsigned long block_size, int read_only, 2965 char **error, int *created) 2966 { 2967 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev); 2968 2969 if (pool) { 2970 if (pool->pool_md != pool_md) { 2971 *error = "metadata device already in use by a pool"; 2972 return ERR_PTR(-EBUSY); 2973 } 2974 __pool_inc(pool); 2975 2976 } else { 2977 pool = __pool_table_lookup(pool_md); 2978 if (pool) { 2979 if (pool->md_dev != metadata_dev) { 2980 *error = "different pool cannot replace a pool"; 2981 return ERR_PTR(-EINVAL); 2982 } 2983 __pool_inc(pool); 2984 2985 } else { 2986 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error); 2987 *created = 1; 2988 } 2989 } 2990 2991 return pool; 2992 } 2993 2994 /*---------------------------------------------------------------- 2995 * Pool target methods 2996 *--------------------------------------------------------------*/ 2997 static void pool_dtr(struct dm_target *ti) 2998 { 2999 struct pool_c *pt = ti->private; 3000 3001 mutex_lock(&dm_thin_pool_table.mutex); 3002 3003 unbind_control_target(pt->pool, ti); 3004 __pool_dec(pt->pool); 3005 dm_put_device(ti, pt->metadata_dev); 3006 dm_put_device(ti, pt->data_dev); 3007 kfree(pt); 3008 3009 mutex_unlock(&dm_thin_pool_table.mutex); 3010 } 3011 3012 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf, 3013 struct dm_target *ti) 3014 { 3015 int r; 3016 unsigned argc; 3017 const char *arg_name; 3018 3019 static struct dm_arg _args[] = { 3020 {0, 4, "Invalid number of pool feature arguments"}, 3021 }; 3022 3023 /* 3024 * No feature arguments supplied. 3025 */ 3026 if (!as->argc) 3027 return 0; 3028 3029 r = dm_read_arg_group(_args, as, &argc, &ti->error); 3030 if (r) 3031 return -EINVAL; 3032 3033 while (argc && !r) { 3034 arg_name = dm_shift_arg(as); 3035 argc--; 3036 3037 if (!strcasecmp(arg_name, "skip_block_zeroing")) 3038 pf->zero_new_blocks = false; 3039 3040 else if (!strcasecmp(arg_name, "ignore_discard")) 3041 pf->discard_enabled = false; 3042 3043 else if (!strcasecmp(arg_name, "no_discard_passdown")) 3044 pf->discard_passdown = false; 3045 3046 else if (!strcasecmp(arg_name, "read_only")) 3047 pf->mode = PM_READ_ONLY; 3048 3049 else if (!strcasecmp(arg_name, "error_if_no_space")) 3050 pf->error_if_no_space = true; 3051 3052 else { 3053 ti->error = "Unrecognised pool feature requested"; 3054 r = -EINVAL; 3055 break; 3056 } 3057 } 3058 3059 return r; 3060 } 3061 3062 static void metadata_low_callback(void *context) 3063 { 3064 struct pool *pool = context; 3065 3066 DMWARN("%s: reached low water mark for metadata device: sending event.", 3067 dm_device_name(pool->pool_md)); 3068 3069 dm_table_event(pool->ti->table); 3070 } 3071 3072 static sector_t get_dev_size(struct block_device *bdev) 3073 { 3074 return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT; 3075 } 3076 3077 static void warn_if_metadata_device_too_big(struct block_device *bdev) 3078 { 3079 sector_t metadata_dev_size = get_dev_size(bdev); 3080 char buffer[BDEVNAME_SIZE]; 3081 3082 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING) 3083 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", 3084 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS); 3085 } 3086 3087 static sector_t get_metadata_dev_size(struct block_device *bdev) 3088 { 3089 sector_t metadata_dev_size = get_dev_size(bdev); 3090 3091 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS) 3092 metadata_dev_size = THIN_METADATA_MAX_SECTORS; 3093 3094 return metadata_dev_size; 3095 } 3096 3097 static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev) 3098 { 3099 sector_t metadata_dev_size = get_metadata_dev_size(bdev); 3100 3101 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE); 3102 3103 return metadata_dev_size; 3104 } 3105 3106 /* 3107 * When a metadata threshold is crossed a dm event is triggered, and 3108 * userland should respond by growing the metadata device. We could let 3109 * userland set the threshold, like we do with the data threshold, but I'm 3110 * not sure they know enough to do this well. 3111 */ 3112 static dm_block_t calc_metadata_threshold(struct pool_c *pt) 3113 { 3114 /* 3115 * 4M is ample for all ops with the possible exception of thin 3116 * device deletion which is harmless if it fails (just retry the 3117 * delete after you've grown the device). 3118 */ 3119 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4; 3120 return min((dm_block_t)1024ULL /* 4M */, quarter); 3121 } 3122 3123 /* 3124 * thin-pool <metadata dev> <data dev> 3125 * <data block size (sectors)> 3126 * <low water mark (blocks)> 3127 * [<#feature args> [<arg>]*] 3128 * 3129 * Optional feature arguments are: 3130 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks. 3131 * ignore_discard: disable discard 3132 * no_discard_passdown: don't pass discards down to the data device 3133 * read_only: Don't allow any changes to be made to the pool metadata. 3134 * error_if_no_space: error IOs, instead of queueing, if no space. 3135 */ 3136 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv) 3137 { 3138 int r, pool_created = 0; 3139 struct pool_c *pt; 3140 struct pool *pool; 3141 struct pool_features pf; 3142 struct dm_arg_set as; 3143 struct dm_dev *data_dev; 3144 unsigned long block_size; 3145 dm_block_t low_water_blocks; 3146 struct dm_dev *metadata_dev; 3147 fmode_t metadata_mode; 3148 3149 /* 3150 * FIXME Remove validation from scope of lock. 3151 */ 3152 mutex_lock(&dm_thin_pool_table.mutex); 3153 3154 if (argc < 4) { 3155 ti->error = "Invalid argument count"; 3156 r = -EINVAL; 3157 goto out_unlock; 3158 } 3159 3160 as.argc = argc; 3161 as.argv = argv; 3162 3163 /* 3164 * Set default pool features. 3165 */ 3166 pool_features_init(&pf); 3167 3168 dm_consume_args(&as, 4); 3169 r = parse_pool_features(&as, &pf, ti); 3170 if (r) 3171 goto out_unlock; 3172 3173 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE); 3174 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev); 3175 if (r) { 3176 ti->error = "Error opening metadata block device"; 3177 goto out_unlock; 3178 } 3179 warn_if_metadata_device_too_big(metadata_dev->bdev); 3180 3181 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev); 3182 if (r) { 3183 ti->error = "Error getting data device"; 3184 goto out_metadata; 3185 } 3186 3187 if (kstrtoul(argv[2], 10, &block_size) || !block_size || 3188 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || 3189 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || 3190 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { 3191 ti->error = "Invalid block size"; 3192 r = -EINVAL; 3193 goto out; 3194 } 3195 3196 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) { 3197 ti->error = "Invalid low water mark"; 3198 r = -EINVAL; 3199 goto out; 3200 } 3201 3202 pt = kzalloc(sizeof(*pt), GFP_KERNEL); 3203 if (!pt) { 3204 r = -ENOMEM; 3205 goto out; 3206 } 3207 3208 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, 3209 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created); 3210 if (IS_ERR(pool)) { 3211 r = PTR_ERR(pool); 3212 goto out_free_pt; 3213 } 3214 3215 /* 3216 * 'pool_created' reflects whether this is the first table load. 3217 * Top level discard support is not allowed to be changed after 3218 * initial load. This would require a pool reload to trigger thin 3219 * device changes. 3220 */ 3221 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) { 3222 ti->error = "Discard support cannot be disabled once enabled"; 3223 r = -EINVAL; 3224 goto out_flags_changed; 3225 } 3226 3227 pt->pool = pool; 3228 pt->ti = ti; 3229 pt->metadata_dev = metadata_dev; 3230 pt->data_dev = data_dev; 3231 pt->low_water_blocks = low_water_blocks; 3232 pt->adjusted_pf = pt->requested_pf = pf; 3233 ti->num_flush_bios = 1; 3234 3235 /* 3236 * Only need to enable discards if the pool should pass 3237 * them down to the data device. The thin device's discard 3238 * processing will cause mappings to be removed from the btree. 3239 */ 3240 ti->discard_zeroes_data_unsupported = true; 3241 if (pf.discard_enabled && pf.discard_passdown) { 3242 ti->num_discard_bios = 1; 3243 3244 /* 3245 * Setting 'discards_supported' circumvents the normal 3246 * stacking of discard limits (this keeps the pool and 3247 * thin devices' discard limits consistent). 3248 */ 3249 ti->discards_supported = true; 3250 } 3251 ti->private = pt; 3252 3253 r = dm_pool_register_metadata_threshold(pt->pool->pmd, 3254 calc_metadata_threshold(pt), 3255 metadata_low_callback, 3256 pool); 3257 if (r) 3258 goto out_free_pt; 3259 3260 pt->callbacks.congested_fn = pool_is_congested; 3261 dm_table_add_target_callbacks(ti->table, &pt->callbacks); 3262 3263 mutex_unlock(&dm_thin_pool_table.mutex); 3264 3265 return 0; 3266 3267 out_flags_changed: 3268 __pool_dec(pool); 3269 out_free_pt: 3270 kfree(pt); 3271 out: 3272 dm_put_device(ti, data_dev); 3273 out_metadata: 3274 dm_put_device(ti, metadata_dev); 3275 out_unlock: 3276 mutex_unlock(&dm_thin_pool_table.mutex); 3277 3278 return r; 3279 } 3280 3281 static int pool_map(struct dm_target *ti, struct bio *bio) 3282 { 3283 int r; 3284 struct pool_c *pt = ti->private; 3285 struct pool *pool = pt->pool; 3286 unsigned long flags; 3287 3288 /* 3289 * As this is a singleton target, ti->begin is always zero. 3290 */ 3291 spin_lock_irqsave(&pool->lock, flags); 3292 bio->bi_bdev = pt->data_dev->bdev; 3293 r = DM_MAPIO_REMAPPED; 3294 spin_unlock_irqrestore(&pool->lock, flags); 3295 3296 return r; 3297 } 3298 3299 static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit) 3300 { 3301 int r; 3302 struct pool_c *pt = ti->private; 3303 struct pool *pool = pt->pool; 3304 sector_t data_size = ti->len; 3305 dm_block_t sb_data_size; 3306 3307 *need_commit = false; 3308 3309 (void) sector_div(data_size, pool->sectors_per_block); 3310 3311 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size); 3312 if (r) { 3313 DMERR("%s: failed to retrieve data device size", 3314 dm_device_name(pool->pool_md)); 3315 return r; 3316 } 3317 3318 if (data_size < sb_data_size) { 3319 DMERR("%s: pool target (%llu blocks) too small: expected %llu", 3320 dm_device_name(pool->pool_md), 3321 (unsigned long long)data_size, sb_data_size); 3322 return -EINVAL; 3323 3324 } else if (data_size > sb_data_size) { 3325 if (dm_pool_metadata_needs_check(pool->pmd)) { 3326 DMERR("%s: unable to grow the data device until repaired.", 3327 dm_device_name(pool->pool_md)); 3328 return 0; 3329 } 3330 3331 if (sb_data_size) 3332 DMINFO("%s: growing the data device from %llu to %llu blocks", 3333 dm_device_name(pool->pool_md), 3334 sb_data_size, (unsigned long long)data_size); 3335 r = dm_pool_resize_data_dev(pool->pmd, data_size); 3336 if (r) { 3337 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r); 3338 return r; 3339 } 3340 3341 *need_commit = true; 3342 } 3343 3344 return 0; 3345 } 3346 3347 static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit) 3348 { 3349 int r; 3350 struct pool_c *pt = ti->private; 3351 struct pool *pool = pt->pool; 3352 dm_block_t metadata_dev_size, sb_metadata_dev_size; 3353 3354 *need_commit = false; 3355 3356 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev); 3357 3358 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size); 3359 if (r) { 3360 DMERR("%s: failed to retrieve metadata device size", 3361 dm_device_name(pool->pool_md)); 3362 return r; 3363 } 3364 3365 if (metadata_dev_size < sb_metadata_dev_size) { 3366 DMERR("%s: metadata device (%llu blocks) too small: expected %llu", 3367 dm_device_name(pool->pool_md), 3368 metadata_dev_size, sb_metadata_dev_size); 3369 return -EINVAL; 3370 3371 } else if (metadata_dev_size > sb_metadata_dev_size) { 3372 if (dm_pool_metadata_needs_check(pool->pmd)) { 3373 DMERR("%s: unable to grow the metadata device until repaired.", 3374 dm_device_name(pool->pool_md)); 3375 return 0; 3376 } 3377 3378 warn_if_metadata_device_too_big(pool->md_dev); 3379 DMINFO("%s: growing the metadata device from %llu to %llu blocks", 3380 dm_device_name(pool->pool_md), 3381 sb_metadata_dev_size, metadata_dev_size); 3382 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size); 3383 if (r) { 3384 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r); 3385 return r; 3386 } 3387 3388 *need_commit = true; 3389 } 3390 3391 return 0; 3392 } 3393 3394 /* 3395 * Retrieves the number of blocks of the data device from 3396 * the superblock and compares it to the actual device size, 3397 * thus resizing the data device in case it has grown. 3398 * 3399 * This both copes with opening preallocated data devices in the ctr 3400 * being followed by a resume 3401 * -and- 3402 * calling the resume method individually after userspace has 3403 * grown the data device in reaction to a table event. 3404 */ 3405 static int pool_preresume(struct dm_target *ti) 3406 { 3407 int r; 3408 bool need_commit1, need_commit2; 3409 struct pool_c *pt = ti->private; 3410 struct pool *pool = pt->pool; 3411 3412 /* 3413 * Take control of the pool object. 3414 */ 3415 r = bind_control_target(pool, ti); 3416 if (r) 3417 return r; 3418 3419 r = maybe_resize_data_dev(ti, &need_commit1); 3420 if (r) 3421 return r; 3422 3423 r = maybe_resize_metadata_dev(ti, &need_commit2); 3424 if (r) 3425 return r; 3426 3427 if (need_commit1 || need_commit2) 3428 (void) commit(pool); 3429 3430 return 0; 3431 } 3432 3433 static void pool_suspend_active_thins(struct pool *pool) 3434 { 3435 struct thin_c *tc; 3436 3437 /* Suspend all active thin devices */ 3438 tc = get_first_thin(pool); 3439 while (tc) { 3440 dm_internal_suspend_noflush(tc->thin_md); 3441 tc = get_next_thin(pool, tc); 3442 } 3443 } 3444 3445 static void pool_resume_active_thins(struct pool *pool) 3446 { 3447 struct thin_c *tc; 3448 3449 /* Resume all active thin devices */ 3450 tc = get_first_thin(pool); 3451 while (tc) { 3452 dm_internal_resume(tc->thin_md); 3453 tc = get_next_thin(pool, tc); 3454 } 3455 } 3456 3457 static void pool_resume(struct dm_target *ti) 3458 { 3459 struct pool_c *pt = ti->private; 3460 struct pool *pool = pt->pool; 3461 unsigned long flags; 3462 3463 /* 3464 * Must requeue active_thins' bios and then resume 3465 * active_thins _before_ clearing 'suspend' flag. 3466 */ 3467 requeue_bios(pool); 3468 pool_resume_active_thins(pool); 3469 3470 spin_lock_irqsave(&pool->lock, flags); 3471 pool->low_water_triggered = false; 3472 pool->suspended = false; 3473 spin_unlock_irqrestore(&pool->lock, flags); 3474 3475 do_waker(&pool->waker.work); 3476 } 3477 3478 static void pool_presuspend(struct dm_target *ti) 3479 { 3480 struct pool_c *pt = ti->private; 3481 struct pool *pool = pt->pool; 3482 unsigned long flags; 3483 3484 spin_lock_irqsave(&pool->lock, flags); 3485 pool->suspended = true; 3486 spin_unlock_irqrestore(&pool->lock, flags); 3487 3488 pool_suspend_active_thins(pool); 3489 } 3490 3491 static void pool_presuspend_undo(struct dm_target *ti) 3492 { 3493 struct pool_c *pt = ti->private; 3494 struct pool *pool = pt->pool; 3495 unsigned long flags; 3496 3497 pool_resume_active_thins(pool); 3498 3499 spin_lock_irqsave(&pool->lock, flags); 3500 pool->suspended = false; 3501 spin_unlock_irqrestore(&pool->lock, flags); 3502 } 3503 3504 static void pool_postsuspend(struct dm_target *ti) 3505 { 3506 struct pool_c *pt = ti->private; 3507 struct pool *pool = pt->pool; 3508 3509 cancel_delayed_work(&pool->waker); 3510 cancel_delayed_work(&pool->no_space_timeout); 3511 flush_workqueue(pool->wq); 3512 (void) commit(pool); 3513 } 3514 3515 static int check_arg_count(unsigned argc, unsigned args_required) 3516 { 3517 if (argc != args_required) { 3518 DMWARN("Message received with %u arguments instead of %u.", 3519 argc, args_required); 3520 return -EINVAL; 3521 } 3522 3523 return 0; 3524 } 3525 3526 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning) 3527 { 3528 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) && 3529 *dev_id <= MAX_DEV_ID) 3530 return 0; 3531 3532 if (warning) 3533 DMWARN("Message received with invalid device id: %s", arg); 3534 3535 return -EINVAL; 3536 } 3537 3538 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool) 3539 { 3540 dm_thin_id dev_id; 3541 int r; 3542 3543 r = check_arg_count(argc, 2); 3544 if (r) 3545 return r; 3546 3547 r = read_dev_id(argv[1], &dev_id, 1); 3548 if (r) 3549 return r; 3550 3551 r = dm_pool_create_thin(pool->pmd, dev_id); 3552 if (r) { 3553 DMWARN("Creation of new thinly-provisioned device with id %s failed.", 3554 argv[1]); 3555 return r; 3556 } 3557 3558 return 0; 3559 } 3560 3561 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool) 3562 { 3563 dm_thin_id dev_id; 3564 dm_thin_id origin_dev_id; 3565 int r; 3566 3567 r = check_arg_count(argc, 3); 3568 if (r) 3569 return r; 3570 3571 r = read_dev_id(argv[1], &dev_id, 1); 3572 if (r) 3573 return r; 3574 3575 r = read_dev_id(argv[2], &origin_dev_id, 1); 3576 if (r) 3577 return r; 3578 3579 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id); 3580 if (r) { 3581 DMWARN("Creation of new snapshot %s of device %s failed.", 3582 argv[1], argv[2]); 3583 return r; 3584 } 3585 3586 return 0; 3587 } 3588 3589 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool) 3590 { 3591 dm_thin_id dev_id; 3592 int r; 3593 3594 r = check_arg_count(argc, 2); 3595 if (r) 3596 return r; 3597 3598 r = read_dev_id(argv[1], &dev_id, 1); 3599 if (r) 3600 return r; 3601 3602 r = dm_pool_delete_thin_device(pool->pmd, dev_id); 3603 if (r) 3604 DMWARN("Deletion of thin device %s failed.", argv[1]); 3605 3606 return r; 3607 } 3608 3609 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool) 3610 { 3611 dm_thin_id old_id, new_id; 3612 int r; 3613 3614 r = check_arg_count(argc, 3); 3615 if (r) 3616 return r; 3617 3618 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) { 3619 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]); 3620 return -EINVAL; 3621 } 3622 3623 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) { 3624 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]); 3625 return -EINVAL; 3626 } 3627 3628 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id); 3629 if (r) { 3630 DMWARN("Failed to change transaction id from %s to %s.", 3631 argv[1], argv[2]); 3632 return r; 3633 } 3634 3635 return 0; 3636 } 3637 3638 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool) 3639 { 3640 int r; 3641 3642 r = check_arg_count(argc, 1); 3643 if (r) 3644 return r; 3645 3646 (void) commit(pool); 3647 3648 r = dm_pool_reserve_metadata_snap(pool->pmd); 3649 if (r) 3650 DMWARN("reserve_metadata_snap message failed."); 3651 3652 return r; 3653 } 3654 3655 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool) 3656 { 3657 int r; 3658 3659 r = check_arg_count(argc, 1); 3660 if (r) 3661 return r; 3662 3663 r = dm_pool_release_metadata_snap(pool->pmd); 3664 if (r) 3665 DMWARN("release_metadata_snap message failed."); 3666 3667 return r; 3668 } 3669 3670 /* 3671 * Messages supported: 3672 * create_thin <dev_id> 3673 * create_snap <dev_id> <origin_id> 3674 * delete <dev_id> 3675 * set_transaction_id <current_trans_id> <new_trans_id> 3676 * reserve_metadata_snap 3677 * release_metadata_snap 3678 */ 3679 static int pool_message(struct dm_target *ti, unsigned argc, char **argv) 3680 { 3681 int r = -EINVAL; 3682 struct pool_c *pt = ti->private; 3683 struct pool *pool = pt->pool; 3684 3685 if (get_pool_mode(pool) >= PM_READ_ONLY) { 3686 DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode", 3687 dm_device_name(pool->pool_md)); 3688 return -EOPNOTSUPP; 3689 } 3690 3691 if (!strcasecmp(argv[0], "create_thin")) 3692 r = process_create_thin_mesg(argc, argv, pool); 3693 3694 else if (!strcasecmp(argv[0], "create_snap")) 3695 r = process_create_snap_mesg(argc, argv, pool); 3696 3697 else if (!strcasecmp(argv[0], "delete")) 3698 r = process_delete_mesg(argc, argv, pool); 3699 3700 else if (!strcasecmp(argv[0], "set_transaction_id")) 3701 r = process_set_transaction_id_mesg(argc, argv, pool); 3702 3703 else if (!strcasecmp(argv[0], "reserve_metadata_snap")) 3704 r = process_reserve_metadata_snap_mesg(argc, argv, pool); 3705 3706 else if (!strcasecmp(argv[0], "release_metadata_snap")) 3707 r = process_release_metadata_snap_mesg(argc, argv, pool); 3708 3709 else 3710 DMWARN("Unrecognised thin pool target message received: %s", argv[0]); 3711 3712 if (!r) 3713 (void) commit(pool); 3714 3715 return r; 3716 } 3717 3718 static void emit_flags(struct pool_features *pf, char *result, 3719 unsigned sz, unsigned maxlen) 3720 { 3721 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled + 3722 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) + 3723 pf->error_if_no_space; 3724 DMEMIT("%u ", count); 3725 3726 if (!pf->zero_new_blocks) 3727 DMEMIT("skip_block_zeroing "); 3728 3729 if (!pf->discard_enabled) 3730 DMEMIT("ignore_discard "); 3731 3732 if (!pf->discard_passdown) 3733 DMEMIT("no_discard_passdown "); 3734 3735 if (pf->mode == PM_READ_ONLY) 3736 DMEMIT("read_only "); 3737 3738 if (pf->error_if_no_space) 3739 DMEMIT("error_if_no_space "); 3740 } 3741 3742 /* 3743 * Status line is: 3744 * <transaction id> <used metadata sectors>/<total metadata sectors> 3745 * <used data sectors>/<total data sectors> <held metadata root> 3746 * <pool mode> <discard config> <no space config> <needs_check> 3747 */ 3748 static void pool_status(struct dm_target *ti, status_type_t type, 3749 unsigned status_flags, char *result, unsigned maxlen) 3750 { 3751 int r; 3752 unsigned sz = 0; 3753 uint64_t transaction_id; 3754 dm_block_t nr_free_blocks_data; 3755 dm_block_t nr_free_blocks_metadata; 3756 dm_block_t nr_blocks_data; 3757 dm_block_t nr_blocks_metadata; 3758 dm_block_t held_root; 3759 char buf[BDEVNAME_SIZE]; 3760 char buf2[BDEVNAME_SIZE]; 3761 struct pool_c *pt = ti->private; 3762 struct pool *pool = pt->pool; 3763 3764 switch (type) { 3765 case STATUSTYPE_INFO: 3766 if (get_pool_mode(pool) == PM_FAIL) { 3767 DMEMIT("Fail"); 3768 break; 3769 } 3770 3771 /* Commit to ensure statistics aren't out-of-date */ 3772 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) 3773 (void) commit(pool); 3774 3775 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id); 3776 if (r) { 3777 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d", 3778 dm_device_name(pool->pool_md), r); 3779 goto err; 3780 } 3781 3782 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata); 3783 if (r) { 3784 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d", 3785 dm_device_name(pool->pool_md), r); 3786 goto err; 3787 } 3788 3789 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata); 3790 if (r) { 3791 DMERR("%s: dm_pool_get_metadata_dev_size returned %d", 3792 dm_device_name(pool->pool_md), r); 3793 goto err; 3794 } 3795 3796 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data); 3797 if (r) { 3798 DMERR("%s: dm_pool_get_free_block_count returned %d", 3799 dm_device_name(pool->pool_md), r); 3800 goto err; 3801 } 3802 3803 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data); 3804 if (r) { 3805 DMERR("%s: dm_pool_get_data_dev_size returned %d", 3806 dm_device_name(pool->pool_md), r); 3807 goto err; 3808 } 3809 3810 r = dm_pool_get_metadata_snap(pool->pmd, &held_root); 3811 if (r) { 3812 DMERR("%s: dm_pool_get_metadata_snap returned %d", 3813 dm_device_name(pool->pool_md), r); 3814 goto err; 3815 } 3816 3817 DMEMIT("%llu %llu/%llu %llu/%llu ", 3818 (unsigned long long)transaction_id, 3819 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), 3820 (unsigned long long)nr_blocks_metadata, 3821 (unsigned long long)(nr_blocks_data - nr_free_blocks_data), 3822 (unsigned long long)nr_blocks_data); 3823 3824 if (held_root) 3825 DMEMIT("%llu ", held_root); 3826 else 3827 DMEMIT("- "); 3828 3829 if (pool->pf.mode == PM_OUT_OF_DATA_SPACE) 3830 DMEMIT("out_of_data_space "); 3831 else if (pool->pf.mode == PM_READ_ONLY) 3832 DMEMIT("ro "); 3833 else 3834 DMEMIT("rw "); 3835 3836 if (!pool->pf.discard_enabled) 3837 DMEMIT("ignore_discard "); 3838 else if (pool->pf.discard_passdown) 3839 DMEMIT("discard_passdown "); 3840 else 3841 DMEMIT("no_discard_passdown "); 3842 3843 if (pool->pf.error_if_no_space) 3844 DMEMIT("error_if_no_space "); 3845 else 3846 DMEMIT("queue_if_no_space "); 3847 3848 if (dm_pool_metadata_needs_check(pool->pmd)) 3849 DMEMIT("needs_check "); 3850 else 3851 DMEMIT("- "); 3852 3853 break; 3854 3855 case STATUSTYPE_TABLE: 3856 DMEMIT("%s %s %lu %llu ", 3857 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev), 3858 format_dev_t(buf2, pt->data_dev->bdev->bd_dev), 3859 (unsigned long)pool->sectors_per_block, 3860 (unsigned long long)pt->low_water_blocks); 3861 emit_flags(&pt->requested_pf, result, sz, maxlen); 3862 break; 3863 } 3864 return; 3865 3866 err: 3867 DMEMIT("Error"); 3868 } 3869 3870 static int pool_iterate_devices(struct dm_target *ti, 3871 iterate_devices_callout_fn fn, void *data) 3872 { 3873 struct pool_c *pt = ti->private; 3874 3875 return fn(ti, pt->data_dev, 0, ti->len, data); 3876 } 3877 3878 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm, 3879 struct bio_vec *biovec, int max_size) 3880 { 3881 struct pool_c *pt = ti->private; 3882 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); 3883 3884 if (!q->merge_bvec_fn) 3885 return max_size; 3886 3887 bvm->bi_bdev = pt->data_dev->bdev; 3888 3889 return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); 3890 } 3891 3892 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) 3893 { 3894 struct pool_c *pt = ti->private; 3895 struct pool *pool = pt->pool; 3896 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; 3897 3898 /* 3899 * If max_sectors is smaller than pool->sectors_per_block adjust it 3900 * to the highest possible power-of-2 factor of pool->sectors_per_block. 3901 * This is especially beneficial when the pool's data device is a RAID 3902 * device that has a full stripe width that matches pool->sectors_per_block 3903 * -- because even though partial RAID stripe-sized IOs will be issued to a 3904 * single RAID stripe; when aggregated they will end on a full RAID stripe 3905 * boundary.. which avoids additional partial RAID stripe writes cascading 3906 */ 3907 if (limits->max_sectors < pool->sectors_per_block) { 3908 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) { 3909 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0) 3910 limits->max_sectors--; 3911 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors); 3912 } 3913 } 3914 3915 /* 3916 * If the system-determined stacked limits are compatible with the 3917 * pool's blocksize (io_opt is a factor) do not override them. 3918 */ 3919 if (io_opt_sectors < pool->sectors_per_block || 3920 !is_factor(io_opt_sectors, pool->sectors_per_block)) { 3921 if (is_factor(pool->sectors_per_block, limits->max_sectors)) 3922 blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT); 3923 else 3924 blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT); 3925 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); 3926 } 3927 3928 /* 3929 * pt->adjusted_pf is a staging area for the actual features to use. 3930 * They get transferred to the live pool in bind_control_target() 3931 * called from pool_preresume(). 3932 */ 3933 if (!pt->adjusted_pf.discard_enabled) { 3934 /* 3935 * Must explicitly disallow stacking discard limits otherwise the 3936 * block layer will stack them if pool's data device has support. 3937 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the 3938 * user to see that, so make sure to set all discard limits to 0. 3939 */ 3940 limits->discard_granularity = 0; 3941 return; 3942 } 3943 3944 disable_passdown_if_not_supported(pt); 3945 3946 /* 3947 * The pool uses the same discard limits as the underlying data 3948 * device. DM core has already set this up. 3949 */ 3950 } 3951 3952 static struct target_type pool_target = { 3953 .name = "thin-pool", 3954 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | 3955 DM_TARGET_IMMUTABLE, 3956 .version = {1, 16, 0}, 3957 .module = THIS_MODULE, 3958 .ctr = pool_ctr, 3959 .dtr = pool_dtr, 3960 .map = pool_map, 3961 .presuspend = pool_presuspend, 3962 .presuspend_undo = pool_presuspend_undo, 3963 .postsuspend = pool_postsuspend, 3964 .preresume = pool_preresume, 3965 .resume = pool_resume, 3966 .message = pool_message, 3967 .status = pool_status, 3968 .merge = pool_merge, 3969 .iterate_devices = pool_iterate_devices, 3970 .io_hints = pool_io_hints, 3971 }; 3972 3973 /*---------------------------------------------------------------- 3974 * Thin target methods 3975 *--------------------------------------------------------------*/ 3976 static void thin_get(struct thin_c *tc) 3977 { 3978 atomic_inc(&tc->refcount); 3979 } 3980 3981 static void thin_put(struct thin_c *tc) 3982 { 3983 if (atomic_dec_and_test(&tc->refcount)) 3984 complete(&tc->can_destroy); 3985 } 3986 3987 static void thin_dtr(struct dm_target *ti) 3988 { 3989 struct thin_c *tc = ti->private; 3990 unsigned long flags; 3991 3992 spin_lock_irqsave(&tc->pool->lock, flags); 3993 list_del_rcu(&tc->list); 3994 spin_unlock_irqrestore(&tc->pool->lock, flags); 3995 synchronize_rcu(); 3996 3997 thin_put(tc); 3998 wait_for_completion(&tc->can_destroy); 3999 4000 mutex_lock(&dm_thin_pool_table.mutex); 4001 4002 __pool_dec(tc->pool); 4003 dm_pool_close_thin_device(tc->td); 4004 dm_put_device(ti, tc->pool_dev); 4005 if (tc->origin_dev) 4006 dm_put_device(ti, tc->origin_dev); 4007 kfree(tc); 4008 4009 mutex_unlock(&dm_thin_pool_table.mutex); 4010 } 4011 4012 /* 4013 * Thin target parameters: 4014 * 4015 * <pool_dev> <dev_id> [origin_dev] 4016 * 4017 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool) 4018 * dev_id: the internal device identifier 4019 * origin_dev: a device external to the pool that should act as the origin 4020 * 4021 * If the pool device has discards disabled, they get disabled for the thin 4022 * device as well. 4023 */ 4024 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv) 4025 { 4026 int r; 4027 struct thin_c *tc; 4028 struct dm_dev *pool_dev, *origin_dev; 4029 struct mapped_device *pool_md; 4030 unsigned long flags; 4031 4032 mutex_lock(&dm_thin_pool_table.mutex); 4033 4034 if (argc != 2 && argc != 3) { 4035 ti->error = "Invalid argument count"; 4036 r = -EINVAL; 4037 goto out_unlock; 4038 } 4039 4040 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL); 4041 if (!tc) { 4042 ti->error = "Out of memory"; 4043 r = -ENOMEM; 4044 goto out_unlock; 4045 } 4046 tc->thin_md = dm_table_get_md(ti->table); 4047 spin_lock_init(&tc->lock); 4048 INIT_LIST_HEAD(&tc->deferred_cells); 4049 bio_list_init(&tc->deferred_bio_list); 4050 bio_list_init(&tc->retry_on_resume_list); 4051 tc->sort_bio_list = RB_ROOT; 4052 4053 if (argc == 3) { 4054 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev); 4055 if (r) { 4056 ti->error = "Error opening origin device"; 4057 goto bad_origin_dev; 4058 } 4059 tc->origin_dev = origin_dev; 4060 } 4061 4062 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev); 4063 if (r) { 4064 ti->error = "Error opening pool device"; 4065 goto bad_pool_dev; 4066 } 4067 tc->pool_dev = pool_dev; 4068 4069 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) { 4070 ti->error = "Invalid device id"; 4071 r = -EINVAL; 4072 goto bad_common; 4073 } 4074 4075 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev); 4076 if (!pool_md) { 4077 ti->error = "Couldn't get pool mapped device"; 4078 r = -EINVAL; 4079 goto bad_common; 4080 } 4081 4082 tc->pool = __pool_table_lookup(pool_md); 4083 if (!tc->pool) { 4084 ti->error = "Couldn't find pool object"; 4085 r = -EINVAL; 4086 goto bad_pool_lookup; 4087 } 4088 __pool_inc(tc->pool); 4089 4090 if (get_pool_mode(tc->pool) == PM_FAIL) { 4091 ti->error = "Couldn't open thin device, Pool is in fail mode"; 4092 r = -EINVAL; 4093 goto bad_pool; 4094 } 4095 4096 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td); 4097 if (r) { 4098 ti->error = "Couldn't open thin internal device"; 4099 goto bad_pool; 4100 } 4101 4102 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block); 4103 if (r) 4104 goto bad; 4105 4106 ti->num_flush_bios = 1; 4107 ti->flush_supported = true; 4108 ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook); 4109 4110 /* In case the pool supports discards, pass them on. */ 4111 ti->discard_zeroes_data_unsupported = true; 4112 if (tc->pool->pf.discard_enabled) { 4113 ti->discards_supported = true; 4114 ti->num_discard_bios = 1; 4115 ti->split_discard_bios = false; 4116 } 4117 4118 mutex_unlock(&dm_thin_pool_table.mutex); 4119 4120 spin_lock_irqsave(&tc->pool->lock, flags); 4121 if (tc->pool->suspended) { 4122 spin_unlock_irqrestore(&tc->pool->lock, flags); 4123 mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */ 4124 ti->error = "Unable to activate thin device while pool is suspended"; 4125 r = -EINVAL; 4126 goto bad; 4127 } 4128 atomic_set(&tc->refcount, 1); 4129 init_completion(&tc->can_destroy); 4130 list_add_tail_rcu(&tc->list, &tc->pool->active_thins); 4131 spin_unlock_irqrestore(&tc->pool->lock, flags); 4132 /* 4133 * This synchronize_rcu() call is needed here otherwise we risk a 4134 * wake_worker() call finding no bios to process (because the newly 4135 * added tc isn't yet visible). So this reduces latency since we 4136 * aren't then dependent on the periodic commit to wake_worker(). 4137 */ 4138 synchronize_rcu(); 4139 4140 dm_put(pool_md); 4141 4142 return 0; 4143 4144 bad: 4145 dm_pool_close_thin_device(tc->td); 4146 bad_pool: 4147 __pool_dec(tc->pool); 4148 bad_pool_lookup: 4149 dm_put(pool_md); 4150 bad_common: 4151 dm_put_device(ti, tc->pool_dev); 4152 bad_pool_dev: 4153 if (tc->origin_dev) 4154 dm_put_device(ti, tc->origin_dev); 4155 bad_origin_dev: 4156 kfree(tc); 4157 out_unlock: 4158 mutex_unlock(&dm_thin_pool_table.mutex); 4159 4160 return r; 4161 } 4162 4163 static int thin_map(struct dm_target *ti, struct bio *bio) 4164 { 4165 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector); 4166 4167 return thin_bio_map(ti, bio); 4168 } 4169 4170 static int thin_endio(struct dm_target *ti, struct bio *bio, int err) 4171 { 4172 unsigned long flags; 4173 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 4174 struct list_head work; 4175 struct dm_thin_new_mapping *m, *tmp; 4176 struct pool *pool = h->tc->pool; 4177 4178 if (h->shared_read_entry) { 4179 INIT_LIST_HEAD(&work); 4180 dm_deferred_entry_dec(h->shared_read_entry, &work); 4181 4182 spin_lock_irqsave(&pool->lock, flags); 4183 list_for_each_entry_safe(m, tmp, &work, list) { 4184 list_del(&m->list); 4185 __complete_mapping_preparation(m); 4186 } 4187 spin_unlock_irqrestore(&pool->lock, flags); 4188 } 4189 4190 if (h->all_io_entry) { 4191 INIT_LIST_HEAD(&work); 4192 dm_deferred_entry_dec(h->all_io_entry, &work); 4193 if (!list_empty(&work)) { 4194 spin_lock_irqsave(&pool->lock, flags); 4195 list_for_each_entry_safe(m, tmp, &work, list) 4196 list_add_tail(&m->list, &pool->prepared_discards); 4197 spin_unlock_irqrestore(&pool->lock, flags); 4198 wake_worker(pool); 4199 } 4200 } 4201 4202 if (h->cell) 4203 cell_defer_no_holder(h->tc, h->cell); 4204 4205 return 0; 4206 } 4207 4208 static void thin_presuspend(struct dm_target *ti) 4209 { 4210 struct thin_c *tc = ti->private; 4211 4212 if (dm_noflush_suspending(ti)) 4213 noflush_work(tc, do_noflush_start); 4214 } 4215 4216 static void thin_postsuspend(struct dm_target *ti) 4217 { 4218 struct thin_c *tc = ti->private; 4219 4220 /* 4221 * The dm_noflush_suspending flag has been cleared by now, so 4222 * unfortunately we must always run this. 4223 */ 4224 noflush_work(tc, do_noflush_stop); 4225 } 4226 4227 static int thin_preresume(struct dm_target *ti) 4228 { 4229 struct thin_c *tc = ti->private; 4230 4231 if (tc->origin_dev) 4232 tc->origin_size = get_dev_size(tc->origin_dev->bdev); 4233 4234 return 0; 4235 } 4236 4237 /* 4238 * <nr mapped sectors> <highest mapped sector> 4239 */ 4240 static void thin_status(struct dm_target *ti, status_type_t type, 4241 unsigned status_flags, char *result, unsigned maxlen) 4242 { 4243 int r; 4244 ssize_t sz = 0; 4245 dm_block_t mapped, highest; 4246 char buf[BDEVNAME_SIZE]; 4247 struct thin_c *tc = ti->private; 4248 4249 if (get_pool_mode(tc->pool) == PM_FAIL) { 4250 DMEMIT("Fail"); 4251 return; 4252 } 4253 4254 if (!tc->td) 4255 DMEMIT("-"); 4256 else { 4257 switch (type) { 4258 case STATUSTYPE_INFO: 4259 r = dm_thin_get_mapped_count(tc->td, &mapped); 4260 if (r) { 4261 DMERR("dm_thin_get_mapped_count returned %d", r); 4262 goto err; 4263 } 4264 4265 r = dm_thin_get_highest_mapped_block(tc->td, &highest); 4266 if (r < 0) { 4267 DMERR("dm_thin_get_highest_mapped_block returned %d", r); 4268 goto err; 4269 } 4270 4271 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block); 4272 if (r) 4273 DMEMIT("%llu", ((highest + 1) * 4274 tc->pool->sectors_per_block) - 1); 4275 else 4276 DMEMIT("-"); 4277 break; 4278 4279 case STATUSTYPE_TABLE: 4280 DMEMIT("%s %lu", 4281 format_dev_t(buf, tc->pool_dev->bdev->bd_dev), 4282 (unsigned long) tc->dev_id); 4283 if (tc->origin_dev) 4284 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev)); 4285 break; 4286 } 4287 } 4288 4289 return; 4290 4291 err: 4292 DMEMIT("Error"); 4293 } 4294 4295 static int thin_merge(struct dm_target *ti, struct bvec_merge_data *bvm, 4296 struct bio_vec *biovec, int max_size) 4297 { 4298 struct thin_c *tc = ti->private; 4299 struct request_queue *q = bdev_get_queue(tc->pool_dev->bdev); 4300 4301 if (!q->merge_bvec_fn) 4302 return max_size; 4303 4304 bvm->bi_bdev = tc->pool_dev->bdev; 4305 bvm->bi_sector = dm_target_offset(ti, bvm->bi_sector); 4306 4307 return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); 4308 } 4309 4310 static int thin_iterate_devices(struct dm_target *ti, 4311 iterate_devices_callout_fn fn, void *data) 4312 { 4313 sector_t blocks; 4314 struct thin_c *tc = ti->private; 4315 struct pool *pool = tc->pool; 4316 4317 /* 4318 * We can't call dm_pool_get_data_dev_size() since that blocks. So 4319 * we follow a more convoluted path through to the pool's target. 4320 */ 4321 if (!pool->ti) 4322 return 0; /* nothing is bound */ 4323 4324 blocks = pool->ti->len; 4325 (void) sector_div(blocks, pool->sectors_per_block); 4326 if (blocks) 4327 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data); 4328 4329 return 0; 4330 } 4331 4332 static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) 4333 { 4334 struct thin_c *tc = ti->private; 4335 struct pool *pool = tc->pool; 4336 4337 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; 4338 limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */ 4339 } 4340 4341 static struct target_type thin_target = { 4342 .name = "thin", 4343 .version = {1, 16, 0}, 4344 .module = THIS_MODULE, 4345 .ctr = thin_ctr, 4346 .dtr = thin_dtr, 4347 .map = thin_map, 4348 .end_io = thin_endio, 4349 .preresume = thin_preresume, 4350 .presuspend = thin_presuspend, 4351 .postsuspend = thin_postsuspend, 4352 .status = thin_status, 4353 .merge = thin_merge, 4354 .iterate_devices = thin_iterate_devices, 4355 .io_hints = thin_io_hints, 4356 }; 4357 4358 /*----------------------------------------------------------------*/ 4359 4360 static int __init dm_thin_init(void) 4361 { 4362 int r; 4363 4364 pool_table_init(); 4365 4366 r = dm_register_target(&thin_target); 4367 if (r) 4368 return r; 4369 4370 r = dm_register_target(&pool_target); 4371 if (r) 4372 goto bad_pool_target; 4373 4374 r = -ENOMEM; 4375 4376 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0); 4377 if (!_new_mapping_cache) 4378 goto bad_new_mapping_cache; 4379 4380 return 0; 4381 4382 bad_new_mapping_cache: 4383 dm_unregister_target(&pool_target); 4384 bad_pool_target: 4385 dm_unregister_target(&thin_target); 4386 4387 return r; 4388 } 4389 4390 static void dm_thin_exit(void) 4391 { 4392 dm_unregister_target(&thin_target); 4393 dm_unregister_target(&pool_target); 4394 4395 kmem_cache_destroy(_new_mapping_cache); 4396 } 4397 4398 module_init(dm_thin_init); 4399 module_exit(dm_thin_exit); 4400 4401 module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR); 4402 MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds"); 4403 4404 MODULE_DESCRIPTION(DM_NAME " thin provisioning target"); 4405 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); 4406 MODULE_LICENSE("GPL"); 4407