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-v1.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 various 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 */ 203 204 /* 205 * Like READ_ONLY, except may switch back to WRITE on metadata resize. Reported as READ_ONLY. 206 */ 207 PM_OUT_OF_METADATA_SPACE, 208 PM_READ_ONLY, /* metadata may not be changed */ 209 210 PM_FAIL, /* all I/O fails */ 211 }; 212 213 struct pool_features { 214 enum pool_mode mode; 215 216 bool zero_new_blocks:1; 217 bool discard_enabled:1; 218 bool discard_passdown:1; 219 bool error_if_no_space:1; 220 }; 221 222 struct thin_c; 223 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio); 224 typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell); 225 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m); 226 227 #define CELL_SORT_ARRAY_SIZE 8192 228 229 struct pool { 230 struct list_head list; 231 struct dm_target *ti; /* Only set if a pool target is bound */ 232 233 struct mapped_device *pool_md; 234 struct block_device *md_dev; 235 struct dm_pool_metadata *pmd; 236 237 dm_block_t low_water_blocks; 238 uint32_t sectors_per_block; 239 int sectors_per_block_shift; 240 241 struct pool_features pf; 242 bool low_water_triggered:1; /* A dm event has been sent */ 243 bool suspended:1; 244 bool out_of_data_space:1; 245 246 struct dm_bio_prison *prison; 247 struct dm_kcopyd_client *copier; 248 249 struct work_struct worker; 250 struct workqueue_struct *wq; 251 struct throttle throttle; 252 struct delayed_work waker; 253 struct delayed_work no_space_timeout; 254 255 unsigned long last_commit_jiffies; 256 unsigned ref_count; 257 258 spinlock_t lock; 259 struct bio_list deferred_flush_bios; 260 struct bio_list deferred_flush_completions; 261 struct list_head prepared_mappings; 262 struct list_head prepared_discards; 263 struct list_head prepared_discards_pt2; 264 struct list_head active_thins; 265 266 struct dm_deferred_set *shared_read_ds; 267 struct dm_deferred_set *all_io_ds; 268 269 struct dm_thin_new_mapping *next_mapping; 270 271 process_bio_fn process_bio; 272 process_bio_fn process_discard; 273 274 process_cell_fn process_cell; 275 process_cell_fn process_discard_cell; 276 277 process_mapping_fn process_prepared_mapping; 278 process_mapping_fn process_prepared_discard; 279 process_mapping_fn process_prepared_discard_pt2; 280 281 struct dm_bio_prison_cell **cell_sort_array; 282 283 mempool_t mapping_pool; 284 }; 285 286 static void metadata_operation_failed(struct pool *pool, const char *op, int r); 287 288 static enum pool_mode get_pool_mode(struct pool *pool) 289 { 290 return pool->pf.mode; 291 } 292 293 static void notify_of_pool_mode_change(struct pool *pool) 294 { 295 const char *descs[] = { 296 "write", 297 "out-of-data-space", 298 "read-only", 299 "read-only", 300 "fail" 301 }; 302 const char *extra_desc = NULL; 303 enum pool_mode mode = get_pool_mode(pool); 304 305 if (mode == PM_OUT_OF_DATA_SPACE) { 306 if (!pool->pf.error_if_no_space) 307 extra_desc = " (queue IO)"; 308 else 309 extra_desc = " (error IO)"; 310 } 311 312 dm_table_event(pool->ti->table); 313 DMINFO("%s: switching pool to %s%s mode", 314 dm_device_name(pool->pool_md), 315 descs[(int)mode], extra_desc ? : ""); 316 } 317 318 /* 319 * Target context for a pool. 320 */ 321 struct pool_c { 322 struct dm_target *ti; 323 struct pool *pool; 324 struct dm_dev *data_dev; 325 struct dm_dev *metadata_dev; 326 struct dm_target_callbacks callbacks; 327 328 dm_block_t low_water_blocks; 329 struct pool_features requested_pf; /* Features requested during table load */ 330 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */ 331 }; 332 333 /* 334 * Target context for a thin. 335 */ 336 struct thin_c { 337 struct list_head list; 338 struct dm_dev *pool_dev; 339 struct dm_dev *origin_dev; 340 sector_t origin_size; 341 dm_thin_id dev_id; 342 343 struct pool *pool; 344 struct dm_thin_device *td; 345 struct mapped_device *thin_md; 346 347 bool requeue_mode:1; 348 spinlock_t lock; 349 struct list_head deferred_cells; 350 struct bio_list deferred_bio_list; 351 struct bio_list retry_on_resume_list; 352 struct rb_root sort_bio_list; /* sorted list of deferred bios */ 353 354 /* 355 * Ensures the thin is not destroyed until the worker has finished 356 * iterating the active_thins list. 357 */ 358 refcount_t refcount; 359 struct completion can_destroy; 360 }; 361 362 /*----------------------------------------------------------------*/ 363 364 static bool block_size_is_power_of_two(struct pool *pool) 365 { 366 return pool->sectors_per_block_shift >= 0; 367 } 368 369 static sector_t block_to_sectors(struct pool *pool, dm_block_t b) 370 { 371 return block_size_is_power_of_two(pool) ? 372 (b << pool->sectors_per_block_shift) : 373 (b * pool->sectors_per_block); 374 } 375 376 /*----------------------------------------------------------------*/ 377 378 struct discard_op { 379 struct thin_c *tc; 380 struct blk_plug plug; 381 struct bio *parent_bio; 382 struct bio *bio; 383 }; 384 385 static void begin_discard(struct discard_op *op, struct thin_c *tc, struct bio *parent) 386 { 387 BUG_ON(!parent); 388 389 op->tc = tc; 390 blk_start_plug(&op->plug); 391 op->parent_bio = parent; 392 op->bio = NULL; 393 } 394 395 static int issue_discard(struct discard_op *op, dm_block_t data_b, dm_block_t data_e) 396 { 397 struct thin_c *tc = op->tc; 398 sector_t s = block_to_sectors(tc->pool, data_b); 399 sector_t len = block_to_sectors(tc->pool, data_e - data_b); 400 401 return __blkdev_issue_discard(tc->pool_dev->bdev, s, len, 402 GFP_NOWAIT, 0, &op->bio); 403 } 404 405 static void end_discard(struct discard_op *op, int r) 406 { 407 if (op->bio) { 408 /* 409 * Even if one of the calls to issue_discard failed, we 410 * need to wait for the chain to complete. 411 */ 412 bio_chain(op->bio, op->parent_bio); 413 bio_set_op_attrs(op->bio, REQ_OP_DISCARD, 0); 414 submit_bio(op->bio); 415 } 416 417 blk_finish_plug(&op->plug); 418 419 /* 420 * Even if r is set, there could be sub discards in flight that we 421 * need to wait for. 422 */ 423 if (r && !op->parent_bio->bi_status) 424 op->parent_bio->bi_status = errno_to_blk_status(r); 425 bio_endio(op->parent_bio); 426 } 427 428 /*----------------------------------------------------------------*/ 429 430 /* 431 * wake_worker() is used when new work is queued and when pool_resume is 432 * ready to continue deferred IO processing. 433 */ 434 static void wake_worker(struct pool *pool) 435 { 436 queue_work(pool->wq, &pool->worker); 437 } 438 439 /*----------------------------------------------------------------*/ 440 441 static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio, 442 struct dm_bio_prison_cell **cell_result) 443 { 444 int r; 445 struct dm_bio_prison_cell *cell_prealloc; 446 447 /* 448 * Allocate a cell from the prison's mempool. 449 * This might block but it can't fail. 450 */ 451 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO); 452 453 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result); 454 if (r) 455 /* 456 * We reused an old cell; we can get rid of 457 * the new one. 458 */ 459 dm_bio_prison_free_cell(pool->prison, cell_prealloc); 460 461 return r; 462 } 463 464 static void cell_release(struct pool *pool, 465 struct dm_bio_prison_cell *cell, 466 struct bio_list *bios) 467 { 468 dm_cell_release(pool->prison, cell, bios); 469 dm_bio_prison_free_cell(pool->prison, cell); 470 } 471 472 static void cell_visit_release(struct pool *pool, 473 void (*fn)(void *, struct dm_bio_prison_cell *), 474 void *context, 475 struct dm_bio_prison_cell *cell) 476 { 477 dm_cell_visit_release(pool->prison, fn, context, cell); 478 dm_bio_prison_free_cell(pool->prison, cell); 479 } 480 481 static void cell_release_no_holder(struct pool *pool, 482 struct dm_bio_prison_cell *cell, 483 struct bio_list *bios) 484 { 485 dm_cell_release_no_holder(pool->prison, cell, bios); 486 dm_bio_prison_free_cell(pool->prison, cell); 487 } 488 489 static void cell_error_with_code(struct pool *pool, 490 struct dm_bio_prison_cell *cell, blk_status_t error_code) 491 { 492 dm_cell_error(pool->prison, cell, error_code); 493 dm_bio_prison_free_cell(pool->prison, cell); 494 } 495 496 static blk_status_t get_pool_io_error_code(struct pool *pool) 497 { 498 return pool->out_of_data_space ? BLK_STS_NOSPC : BLK_STS_IOERR; 499 } 500 501 static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell) 502 { 503 cell_error_with_code(pool, cell, get_pool_io_error_code(pool)); 504 } 505 506 static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell) 507 { 508 cell_error_with_code(pool, cell, 0); 509 } 510 511 static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell) 512 { 513 cell_error_with_code(pool, cell, BLK_STS_DM_REQUEUE); 514 } 515 516 /*----------------------------------------------------------------*/ 517 518 /* 519 * A global list of pools that uses a struct mapped_device as a key. 520 */ 521 static struct dm_thin_pool_table { 522 struct mutex mutex; 523 struct list_head pools; 524 } dm_thin_pool_table; 525 526 static void pool_table_init(void) 527 { 528 mutex_init(&dm_thin_pool_table.mutex); 529 INIT_LIST_HEAD(&dm_thin_pool_table.pools); 530 } 531 532 static void pool_table_exit(void) 533 { 534 mutex_destroy(&dm_thin_pool_table.mutex); 535 } 536 537 static void __pool_table_insert(struct pool *pool) 538 { 539 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); 540 list_add(&pool->list, &dm_thin_pool_table.pools); 541 } 542 543 static void __pool_table_remove(struct pool *pool) 544 { 545 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); 546 list_del(&pool->list); 547 } 548 549 static struct pool *__pool_table_lookup(struct mapped_device *md) 550 { 551 struct pool *pool = NULL, *tmp; 552 553 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); 554 555 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) { 556 if (tmp->pool_md == md) { 557 pool = tmp; 558 break; 559 } 560 } 561 562 return pool; 563 } 564 565 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev) 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->md_dev == md_dev) { 573 pool = tmp; 574 break; 575 } 576 } 577 578 return pool; 579 } 580 581 /*----------------------------------------------------------------*/ 582 583 struct dm_thin_endio_hook { 584 struct thin_c *tc; 585 struct dm_deferred_entry *shared_read_entry; 586 struct dm_deferred_entry *all_io_entry; 587 struct dm_thin_new_mapping *overwrite_mapping; 588 struct rb_node rb_node; 589 struct dm_bio_prison_cell *cell; 590 }; 591 592 static void __merge_bio_list(struct bio_list *bios, struct bio_list *master) 593 { 594 bio_list_merge(bios, master); 595 bio_list_init(master); 596 } 597 598 static void error_bio_list(struct bio_list *bios, blk_status_t error) 599 { 600 struct bio *bio; 601 602 while ((bio = bio_list_pop(bios))) { 603 bio->bi_status = error; 604 bio_endio(bio); 605 } 606 } 607 608 static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master, 609 blk_status_t error) 610 { 611 struct bio_list bios; 612 613 bio_list_init(&bios); 614 615 spin_lock_irq(&tc->lock); 616 __merge_bio_list(&bios, master); 617 spin_unlock_irq(&tc->lock); 618 619 error_bio_list(&bios, error); 620 } 621 622 static void requeue_deferred_cells(struct thin_c *tc) 623 { 624 struct pool *pool = tc->pool; 625 struct list_head cells; 626 struct dm_bio_prison_cell *cell, *tmp; 627 628 INIT_LIST_HEAD(&cells); 629 630 spin_lock_irq(&tc->lock); 631 list_splice_init(&tc->deferred_cells, &cells); 632 spin_unlock_irq(&tc->lock); 633 634 list_for_each_entry_safe(cell, tmp, &cells, user_list) 635 cell_requeue(pool, cell); 636 } 637 638 static void requeue_io(struct thin_c *tc) 639 { 640 struct bio_list bios; 641 642 bio_list_init(&bios); 643 644 spin_lock_irq(&tc->lock); 645 __merge_bio_list(&bios, &tc->deferred_bio_list); 646 __merge_bio_list(&bios, &tc->retry_on_resume_list); 647 spin_unlock_irq(&tc->lock); 648 649 error_bio_list(&bios, BLK_STS_DM_REQUEUE); 650 requeue_deferred_cells(tc); 651 } 652 653 static void error_retry_list_with_code(struct pool *pool, blk_status_t error) 654 { 655 struct thin_c *tc; 656 657 rcu_read_lock(); 658 list_for_each_entry_rcu(tc, &pool->active_thins, list) 659 error_thin_bio_list(tc, &tc->retry_on_resume_list, error); 660 rcu_read_unlock(); 661 } 662 663 static void error_retry_list(struct pool *pool) 664 { 665 error_retry_list_with_code(pool, get_pool_io_error_code(pool)); 666 } 667 668 /* 669 * This section of code contains the logic for processing a thin device's IO. 670 * Much of the code depends on pool object resources (lists, workqueues, etc) 671 * but most is exclusively called from the thin target rather than the thin-pool 672 * target. 673 */ 674 675 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio) 676 { 677 struct pool *pool = tc->pool; 678 sector_t block_nr = bio->bi_iter.bi_sector; 679 680 if (block_size_is_power_of_two(pool)) 681 block_nr >>= pool->sectors_per_block_shift; 682 else 683 (void) sector_div(block_nr, pool->sectors_per_block); 684 685 return block_nr; 686 } 687 688 /* 689 * Returns the _complete_ blocks that this bio covers. 690 */ 691 static void get_bio_block_range(struct thin_c *tc, struct bio *bio, 692 dm_block_t *begin, dm_block_t *end) 693 { 694 struct pool *pool = tc->pool; 695 sector_t b = bio->bi_iter.bi_sector; 696 sector_t e = b + (bio->bi_iter.bi_size >> SECTOR_SHIFT); 697 698 b += pool->sectors_per_block - 1ull; /* so we round up */ 699 700 if (block_size_is_power_of_two(pool)) { 701 b >>= pool->sectors_per_block_shift; 702 e >>= pool->sectors_per_block_shift; 703 } else { 704 (void) sector_div(b, pool->sectors_per_block); 705 (void) sector_div(e, pool->sectors_per_block); 706 } 707 708 if (e < b) 709 /* Can happen if the bio is within a single block. */ 710 e = b; 711 712 *begin = b; 713 *end = e; 714 } 715 716 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block) 717 { 718 struct pool *pool = tc->pool; 719 sector_t bi_sector = bio->bi_iter.bi_sector; 720 721 bio_set_dev(bio, tc->pool_dev->bdev); 722 if (block_size_is_power_of_two(pool)) 723 bio->bi_iter.bi_sector = 724 (block << pool->sectors_per_block_shift) | 725 (bi_sector & (pool->sectors_per_block - 1)); 726 else 727 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) + 728 sector_div(bi_sector, pool->sectors_per_block); 729 } 730 731 static void remap_to_origin(struct thin_c *tc, struct bio *bio) 732 { 733 bio_set_dev(bio, tc->origin_dev->bdev); 734 } 735 736 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio) 737 { 738 return op_is_flush(bio->bi_opf) && 739 dm_thin_changed_this_transaction(tc->td); 740 } 741 742 static void inc_all_io_entry(struct pool *pool, struct bio *bio) 743 { 744 struct dm_thin_endio_hook *h; 745 746 if (bio_op(bio) == REQ_OP_DISCARD) 747 return; 748 749 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 750 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds); 751 } 752 753 static void issue(struct thin_c *tc, struct bio *bio) 754 { 755 struct pool *pool = tc->pool; 756 757 if (!bio_triggers_commit(tc, bio)) { 758 generic_make_request(bio); 759 return; 760 } 761 762 /* 763 * Complete bio with an error if earlier I/O caused changes to 764 * the metadata that can't be committed e.g, due to I/O errors 765 * on the metadata device. 766 */ 767 if (dm_thin_aborted_changes(tc->td)) { 768 bio_io_error(bio); 769 return; 770 } 771 772 /* 773 * Batch together any bios that trigger commits and then issue a 774 * single commit for them in process_deferred_bios(). 775 */ 776 spin_lock_irq(&pool->lock); 777 bio_list_add(&pool->deferred_flush_bios, bio); 778 spin_unlock_irq(&pool->lock); 779 } 780 781 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio) 782 { 783 remap_to_origin(tc, bio); 784 issue(tc, bio); 785 } 786 787 static void remap_and_issue(struct thin_c *tc, struct bio *bio, 788 dm_block_t block) 789 { 790 remap(tc, bio, block); 791 issue(tc, bio); 792 } 793 794 /*----------------------------------------------------------------*/ 795 796 /* 797 * Bio endio functions. 798 */ 799 struct dm_thin_new_mapping { 800 struct list_head list; 801 802 bool pass_discard:1; 803 bool maybe_shared:1; 804 805 /* 806 * Track quiescing, copying and zeroing preparation actions. When this 807 * counter hits zero the block is prepared and can be inserted into the 808 * btree. 809 */ 810 atomic_t prepare_actions; 811 812 blk_status_t status; 813 struct thin_c *tc; 814 dm_block_t virt_begin, virt_end; 815 dm_block_t data_block; 816 struct dm_bio_prison_cell *cell; 817 818 /* 819 * If the bio covers the whole area of a block then we can avoid 820 * zeroing or copying. Instead this bio is hooked. The bio will 821 * still be in the cell, so care has to be taken to avoid issuing 822 * the bio twice. 823 */ 824 struct bio *bio; 825 bio_end_io_t *saved_bi_end_io; 826 }; 827 828 static void __complete_mapping_preparation(struct dm_thin_new_mapping *m) 829 { 830 struct pool *pool = m->tc->pool; 831 832 if (atomic_dec_and_test(&m->prepare_actions)) { 833 list_add_tail(&m->list, &pool->prepared_mappings); 834 wake_worker(pool); 835 } 836 } 837 838 static void complete_mapping_preparation(struct dm_thin_new_mapping *m) 839 { 840 unsigned long flags; 841 struct pool *pool = m->tc->pool; 842 843 spin_lock_irqsave(&pool->lock, flags); 844 __complete_mapping_preparation(m); 845 spin_unlock_irqrestore(&pool->lock, flags); 846 } 847 848 static void copy_complete(int read_err, unsigned long write_err, void *context) 849 { 850 struct dm_thin_new_mapping *m = context; 851 852 m->status = read_err || write_err ? BLK_STS_IOERR : 0; 853 complete_mapping_preparation(m); 854 } 855 856 static void overwrite_endio(struct bio *bio) 857 { 858 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 859 struct dm_thin_new_mapping *m = h->overwrite_mapping; 860 861 bio->bi_end_io = m->saved_bi_end_io; 862 863 m->status = bio->bi_status; 864 complete_mapping_preparation(m); 865 } 866 867 /*----------------------------------------------------------------*/ 868 869 /* 870 * Workqueue. 871 */ 872 873 /* 874 * Prepared mapping jobs. 875 */ 876 877 /* 878 * This sends the bios in the cell, except the original holder, back 879 * to the deferred_bios list. 880 */ 881 static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell) 882 { 883 struct pool *pool = tc->pool; 884 unsigned long flags; 885 int has_work; 886 887 spin_lock_irqsave(&tc->lock, flags); 888 cell_release_no_holder(pool, cell, &tc->deferred_bio_list); 889 has_work = !bio_list_empty(&tc->deferred_bio_list); 890 spin_unlock_irqrestore(&tc->lock, flags); 891 892 if (has_work) 893 wake_worker(pool); 894 } 895 896 static void thin_defer_bio(struct thin_c *tc, struct bio *bio); 897 898 struct remap_info { 899 struct thin_c *tc; 900 struct bio_list defer_bios; 901 struct bio_list issue_bios; 902 }; 903 904 static void __inc_remap_and_issue_cell(void *context, 905 struct dm_bio_prison_cell *cell) 906 { 907 struct remap_info *info = context; 908 struct bio *bio; 909 910 while ((bio = bio_list_pop(&cell->bios))) { 911 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) 912 bio_list_add(&info->defer_bios, bio); 913 else { 914 inc_all_io_entry(info->tc->pool, bio); 915 916 /* 917 * We can't issue the bios with the bio prison lock 918 * held, so we add them to a list to issue on 919 * return from this function. 920 */ 921 bio_list_add(&info->issue_bios, bio); 922 } 923 } 924 } 925 926 static void inc_remap_and_issue_cell(struct thin_c *tc, 927 struct dm_bio_prison_cell *cell, 928 dm_block_t block) 929 { 930 struct bio *bio; 931 struct remap_info info; 932 933 info.tc = tc; 934 bio_list_init(&info.defer_bios); 935 bio_list_init(&info.issue_bios); 936 937 /* 938 * We have to be careful to inc any bios we're about to issue 939 * before the cell is released, and avoid a race with new bios 940 * being added to the cell. 941 */ 942 cell_visit_release(tc->pool, __inc_remap_and_issue_cell, 943 &info, cell); 944 945 while ((bio = bio_list_pop(&info.defer_bios))) 946 thin_defer_bio(tc, bio); 947 948 while ((bio = bio_list_pop(&info.issue_bios))) 949 remap_and_issue(info.tc, bio, block); 950 } 951 952 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m) 953 { 954 cell_error(m->tc->pool, m->cell); 955 list_del(&m->list); 956 mempool_free(m, &m->tc->pool->mapping_pool); 957 } 958 959 static void complete_overwrite_bio(struct thin_c *tc, struct bio *bio) 960 { 961 struct pool *pool = tc->pool; 962 963 /* 964 * If the bio has the REQ_FUA flag set we must commit the metadata 965 * before signaling its completion. 966 */ 967 if (!bio_triggers_commit(tc, bio)) { 968 bio_endio(bio); 969 return; 970 } 971 972 /* 973 * Complete bio with an error if earlier I/O caused changes to the 974 * metadata that can't be committed, e.g, due to I/O errors on the 975 * metadata device. 976 */ 977 if (dm_thin_aborted_changes(tc->td)) { 978 bio_io_error(bio); 979 return; 980 } 981 982 /* 983 * Batch together any bios that trigger commits and then issue a 984 * single commit for them in process_deferred_bios(). 985 */ 986 spin_lock_irq(&pool->lock); 987 bio_list_add(&pool->deferred_flush_completions, bio); 988 spin_unlock_irq(&pool->lock); 989 } 990 991 static void process_prepared_mapping(struct dm_thin_new_mapping *m) 992 { 993 struct thin_c *tc = m->tc; 994 struct pool *pool = tc->pool; 995 struct bio *bio = m->bio; 996 int r; 997 998 if (m->status) { 999 cell_error(pool, m->cell); 1000 goto out; 1001 } 1002 1003 /* 1004 * Commit the prepared block into the mapping btree. 1005 * Any I/O for this block arriving after this point will get 1006 * remapped to it directly. 1007 */ 1008 r = dm_thin_insert_block(tc->td, m->virt_begin, m->data_block); 1009 if (r) { 1010 metadata_operation_failed(pool, "dm_thin_insert_block", r); 1011 cell_error(pool, m->cell); 1012 goto out; 1013 } 1014 1015 /* 1016 * Release any bios held while the block was being provisioned. 1017 * If we are processing a write bio that completely covers the block, 1018 * we already processed it so can ignore it now when processing 1019 * the bios in the cell. 1020 */ 1021 if (bio) { 1022 inc_remap_and_issue_cell(tc, m->cell, m->data_block); 1023 complete_overwrite_bio(tc, bio); 1024 } else { 1025 inc_all_io_entry(tc->pool, m->cell->holder); 1026 remap_and_issue(tc, m->cell->holder, m->data_block); 1027 inc_remap_and_issue_cell(tc, m->cell, m->data_block); 1028 } 1029 1030 out: 1031 list_del(&m->list); 1032 mempool_free(m, &pool->mapping_pool); 1033 } 1034 1035 /*----------------------------------------------------------------*/ 1036 1037 static void free_discard_mapping(struct dm_thin_new_mapping *m) 1038 { 1039 struct thin_c *tc = m->tc; 1040 if (m->cell) 1041 cell_defer_no_holder(tc, m->cell); 1042 mempool_free(m, &tc->pool->mapping_pool); 1043 } 1044 1045 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m) 1046 { 1047 bio_io_error(m->bio); 1048 free_discard_mapping(m); 1049 } 1050 1051 static void process_prepared_discard_success(struct dm_thin_new_mapping *m) 1052 { 1053 bio_endio(m->bio); 1054 free_discard_mapping(m); 1055 } 1056 1057 static void process_prepared_discard_no_passdown(struct dm_thin_new_mapping *m) 1058 { 1059 int r; 1060 struct thin_c *tc = m->tc; 1061 1062 r = dm_thin_remove_range(tc->td, m->cell->key.block_begin, m->cell->key.block_end); 1063 if (r) { 1064 metadata_operation_failed(tc->pool, "dm_thin_remove_range", r); 1065 bio_io_error(m->bio); 1066 } else 1067 bio_endio(m->bio); 1068 1069 cell_defer_no_holder(tc, m->cell); 1070 mempool_free(m, &tc->pool->mapping_pool); 1071 } 1072 1073 /*----------------------------------------------------------------*/ 1074 1075 static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m, 1076 struct bio *discard_parent) 1077 { 1078 /* 1079 * We've already unmapped this range of blocks, but before we 1080 * passdown we have to check that these blocks are now unused. 1081 */ 1082 int r = 0; 1083 bool shared = true; 1084 struct thin_c *tc = m->tc; 1085 struct pool *pool = tc->pool; 1086 dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin; 1087 struct discard_op op; 1088 1089 begin_discard(&op, tc, discard_parent); 1090 while (b != end) { 1091 /* find start of unmapped run */ 1092 for (; b < end; b++) { 1093 r = dm_pool_block_is_shared(pool->pmd, b, &shared); 1094 if (r) 1095 goto out; 1096 1097 if (!shared) 1098 break; 1099 } 1100 1101 if (b == end) 1102 break; 1103 1104 /* find end of run */ 1105 for (e = b + 1; e != end; e++) { 1106 r = dm_pool_block_is_shared(pool->pmd, e, &shared); 1107 if (r) 1108 goto out; 1109 1110 if (shared) 1111 break; 1112 } 1113 1114 r = issue_discard(&op, b, e); 1115 if (r) 1116 goto out; 1117 1118 b = e; 1119 } 1120 out: 1121 end_discard(&op, r); 1122 } 1123 1124 static void queue_passdown_pt2(struct dm_thin_new_mapping *m) 1125 { 1126 unsigned long flags; 1127 struct pool *pool = m->tc->pool; 1128 1129 spin_lock_irqsave(&pool->lock, flags); 1130 list_add_tail(&m->list, &pool->prepared_discards_pt2); 1131 spin_unlock_irqrestore(&pool->lock, flags); 1132 wake_worker(pool); 1133 } 1134 1135 static void passdown_endio(struct bio *bio) 1136 { 1137 /* 1138 * It doesn't matter if the passdown discard failed, we still want 1139 * to unmap (we ignore err). 1140 */ 1141 queue_passdown_pt2(bio->bi_private); 1142 bio_put(bio); 1143 } 1144 1145 static void process_prepared_discard_passdown_pt1(struct dm_thin_new_mapping *m) 1146 { 1147 int r; 1148 struct thin_c *tc = m->tc; 1149 struct pool *pool = tc->pool; 1150 struct bio *discard_parent; 1151 dm_block_t data_end = m->data_block + (m->virt_end - m->virt_begin); 1152 1153 /* 1154 * Only this thread allocates blocks, so we can be sure that the 1155 * newly unmapped blocks will not be allocated before the end of 1156 * the function. 1157 */ 1158 r = dm_thin_remove_range(tc->td, m->virt_begin, m->virt_end); 1159 if (r) { 1160 metadata_operation_failed(pool, "dm_thin_remove_range", r); 1161 bio_io_error(m->bio); 1162 cell_defer_no_holder(tc, m->cell); 1163 mempool_free(m, &pool->mapping_pool); 1164 return; 1165 } 1166 1167 /* 1168 * Increment the unmapped blocks. This prevents a race between the 1169 * passdown io and reallocation of freed blocks. 1170 */ 1171 r = dm_pool_inc_data_range(pool->pmd, m->data_block, data_end); 1172 if (r) { 1173 metadata_operation_failed(pool, "dm_pool_inc_data_range", r); 1174 bio_io_error(m->bio); 1175 cell_defer_no_holder(tc, m->cell); 1176 mempool_free(m, &pool->mapping_pool); 1177 return; 1178 } 1179 1180 discard_parent = bio_alloc(GFP_NOIO, 1); 1181 if (!discard_parent) { 1182 DMWARN("%s: unable to allocate top level discard bio for passdown. Skipping passdown.", 1183 dm_device_name(tc->pool->pool_md)); 1184 queue_passdown_pt2(m); 1185 1186 } else { 1187 discard_parent->bi_end_io = passdown_endio; 1188 discard_parent->bi_private = m; 1189 1190 if (m->maybe_shared) 1191 passdown_double_checking_shared_status(m, discard_parent); 1192 else { 1193 struct discard_op op; 1194 1195 begin_discard(&op, tc, discard_parent); 1196 r = issue_discard(&op, m->data_block, data_end); 1197 end_discard(&op, r); 1198 } 1199 } 1200 } 1201 1202 static void process_prepared_discard_passdown_pt2(struct dm_thin_new_mapping *m) 1203 { 1204 int r; 1205 struct thin_c *tc = m->tc; 1206 struct pool *pool = tc->pool; 1207 1208 /* 1209 * The passdown has completed, so now we can decrement all those 1210 * unmapped blocks. 1211 */ 1212 r = dm_pool_dec_data_range(pool->pmd, m->data_block, 1213 m->data_block + (m->virt_end - m->virt_begin)); 1214 if (r) { 1215 metadata_operation_failed(pool, "dm_pool_dec_data_range", r); 1216 bio_io_error(m->bio); 1217 } else 1218 bio_endio(m->bio); 1219 1220 cell_defer_no_holder(tc, m->cell); 1221 mempool_free(m, &pool->mapping_pool); 1222 } 1223 1224 static void process_prepared(struct pool *pool, struct list_head *head, 1225 process_mapping_fn *fn) 1226 { 1227 struct list_head maps; 1228 struct dm_thin_new_mapping *m, *tmp; 1229 1230 INIT_LIST_HEAD(&maps); 1231 spin_lock_irq(&pool->lock); 1232 list_splice_init(head, &maps); 1233 spin_unlock_irq(&pool->lock); 1234 1235 list_for_each_entry_safe(m, tmp, &maps, list) 1236 (*fn)(m); 1237 } 1238 1239 /* 1240 * Deferred bio jobs. 1241 */ 1242 static int io_overlaps_block(struct pool *pool, struct bio *bio) 1243 { 1244 return bio->bi_iter.bi_size == 1245 (pool->sectors_per_block << SECTOR_SHIFT); 1246 } 1247 1248 static int io_overwrites_block(struct pool *pool, struct bio *bio) 1249 { 1250 return (bio_data_dir(bio) == WRITE) && 1251 io_overlaps_block(pool, bio); 1252 } 1253 1254 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save, 1255 bio_end_io_t *fn) 1256 { 1257 *save = bio->bi_end_io; 1258 bio->bi_end_io = fn; 1259 } 1260 1261 static int ensure_next_mapping(struct pool *pool) 1262 { 1263 if (pool->next_mapping) 1264 return 0; 1265 1266 pool->next_mapping = mempool_alloc(&pool->mapping_pool, GFP_ATOMIC); 1267 1268 return pool->next_mapping ? 0 : -ENOMEM; 1269 } 1270 1271 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool) 1272 { 1273 struct dm_thin_new_mapping *m = pool->next_mapping; 1274 1275 BUG_ON(!pool->next_mapping); 1276 1277 memset(m, 0, sizeof(struct dm_thin_new_mapping)); 1278 INIT_LIST_HEAD(&m->list); 1279 m->bio = NULL; 1280 1281 pool->next_mapping = NULL; 1282 1283 return m; 1284 } 1285 1286 static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m, 1287 sector_t begin, sector_t end) 1288 { 1289 struct dm_io_region to; 1290 1291 to.bdev = tc->pool_dev->bdev; 1292 to.sector = begin; 1293 to.count = end - begin; 1294 1295 dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m); 1296 } 1297 1298 static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio, 1299 dm_block_t data_begin, 1300 struct dm_thin_new_mapping *m) 1301 { 1302 struct pool *pool = tc->pool; 1303 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 1304 1305 h->overwrite_mapping = m; 1306 m->bio = bio; 1307 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); 1308 inc_all_io_entry(pool, bio); 1309 remap_and_issue(tc, bio, data_begin); 1310 } 1311 1312 /* 1313 * A partial copy also needs to zero the uncopied region. 1314 */ 1315 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, 1316 struct dm_dev *origin, dm_block_t data_origin, 1317 dm_block_t data_dest, 1318 struct dm_bio_prison_cell *cell, struct bio *bio, 1319 sector_t len) 1320 { 1321 struct pool *pool = tc->pool; 1322 struct dm_thin_new_mapping *m = get_next_mapping(pool); 1323 1324 m->tc = tc; 1325 m->virt_begin = virt_block; 1326 m->virt_end = virt_block + 1u; 1327 m->data_block = data_dest; 1328 m->cell = cell; 1329 1330 /* 1331 * quiesce action + copy action + an extra reference held for the 1332 * duration of this function (we may need to inc later for a 1333 * partial zero). 1334 */ 1335 atomic_set(&m->prepare_actions, 3); 1336 1337 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list)) 1338 complete_mapping_preparation(m); /* already quiesced */ 1339 1340 /* 1341 * IO to pool_dev remaps to the pool target's data_dev. 1342 * 1343 * If the whole block of data is being overwritten, we can issue the 1344 * bio immediately. Otherwise we use kcopyd to clone the data first. 1345 */ 1346 if (io_overwrites_block(pool, bio)) 1347 remap_and_issue_overwrite(tc, bio, data_dest, m); 1348 else { 1349 struct dm_io_region from, to; 1350 1351 from.bdev = origin->bdev; 1352 from.sector = data_origin * pool->sectors_per_block; 1353 from.count = len; 1354 1355 to.bdev = tc->pool_dev->bdev; 1356 to.sector = data_dest * pool->sectors_per_block; 1357 to.count = len; 1358 1359 dm_kcopyd_copy(pool->copier, &from, 1, &to, 1360 0, copy_complete, m); 1361 1362 /* 1363 * Do we need to zero a tail region? 1364 */ 1365 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) { 1366 atomic_inc(&m->prepare_actions); 1367 ll_zero(tc, m, 1368 data_dest * pool->sectors_per_block + len, 1369 (data_dest + 1) * pool->sectors_per_block); 1370 } 1371 } 1372 1373 complete_mapping_preparation(m); /* drop our ref */ 1374 } 1375 1376 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block, 1377 dm_block_t data_origin, dm_block_t data_dest, 1378 struct dm_bio_prison_cell *cell, struct bio *bio) 1379 { 1380 schedule_copy(tc, virt_block, tc->pool_dev, 1381 data_origin, data_dest, cell, bio, 1382 tc->pool->sectors_per_block); 1383 } 1384 1385 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, 1386 dm_block_t data_block, struct dm_bio_prison_cell *cell, 1387 struct bio *bio) 1388 { 1389 struct pool *pool = tc->pool; 1390 struct dm_thin_new_mapping *m = get_next_mapping(pool); 1391 1392 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */ 1393 m->tc = tc; 1394 m->virt_begin = virt_block; 1395 m->virt_end = virt_block + 1u; 1396 m->data_block = data_block; 1397 m->cell = cell; 1398 1399 /* 1400 * If the whole block of data is being overwritten or we are not 1401 * zeroing pre-existing data, we can issue the bio immediately. 1402 * Otherwise we use kcopyd to zero the data first. 1403 */ 1404 if (pool->pf.zero_new_blocks) { 1405 if (io_overwrites_block(pool, bio)) 1406 remap_and_issue_overwrite(tc, bio, data_block, m); 1407 else 1408 ll_zero(tc, m, data_block * pool->sectors_per_block, 1409 (data_block + 1) * pool->sectors_per_block); 1410 } else 1411 process_prepared_mapping(m); 1412 } 1413 1414 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block, 1415 dm_block_t data_dest, 1416 struct dm_bio_prison_cell *cell, struct bio *bio) 1417 { 1418 struct pool *pool = tc->pool; 1419 sector_t virt_block_begin = virt_block * pool->sectors_per_block; 1420 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block; 1421 1422 if (virt_block_end <= tc->origin_size) 1423 schedule_copy(tc, virt_block, tc->origin_dev, 1424 virt_block, data_dest, cell, bio, 1425 pool->sectors_per_block); 1426 1427 else if (virt_block_begin < tc->origin_size) 1428 schedule_copy(tc, virt_block, tc->origin_dev, 1429 virt_block, data_dest, cell, bio, 1430 tc->origin_size - virt_block_begin); 1431 1432 else 1433 schedule_zero(tc, virt_block, data_dest, cell, bio); 1434 } 1435 1436 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode); 1437 1438 static void requeue_bios(struct pool *pool); 1439 1440 static bool is_read_only_pool_mode(enum pool_mode mode) 1441 { 1442 return (mode == PM_OUT_OF_METADATA_SPACE || mode == PM_READ_ONLY); 1443 } 1444 1445 static bool is_read_only(struct pool *pool) 1446 { 1447 return is_read_only_pool_mode(get_pool_mode(pool)); 1448 } 1449 1450 static void check_for_metadata_space(struct pool *pool) 1451 { 1452 int r; 1453 const char *ooms_reason = NULL; 1454 dm_block_t nr_free; 1455 1456 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free); 1457 if (r) 1458 ooms_reason = "Could not get free metadata blocks"; 1459 else if (!nr_free) 1460 ooms_reason = "No free metadata blocks"; 1461 1462 if (ooms_reason && !is_read_only(pool)) { 1463 DMERR("%s", ooms_reason); 1464 set_pool_mode(pool, PM_OUT_OF_METADATA_SPACE); 1465 } 1466 } 1467 1468 static void check_for_data_space(struct pool *pool) 1469 { 1470 int r; 1471 dm_block_t nr_free; 1472 1473 if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE) 1474 return; 1475 1476 r = dm_pool_get_free_block_count(pool->pmd, &nr_free); 1477 if (r) 1478 return; 1479 1480 if (nr_free) { 1481 set_pool_mode(pool, PM_WRITE); 1482 requeue_bios(pool); 1483 } 1484 } 1485 1486 /* 1487 * A non-zero return indicates read_only or fail_io mode. 1488 * Many callers don't care about the return value. 1489 */ 1490 static int commit(struct pool *pool) 1491 { 1492 int r; 1493 1494 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE) 1495 return -EINVAL; 1496 1497 r = dm_pool_commit_metadata(pool->pmd); 1498 if (r) 1499 metadata_operation_failed(pool, "dm_pool_commit_metadata", r); 1500 else { 1501 check_for_metadata_space(pool); 1502 check_for_data_space(pool); 1503 } 1504 1505 return r; 1506 } 1507 1508 static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks) 1509 { 1510 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) { 1511 DMWARN("%s: reached low water mark for data device: sending event.", 1512 dm_device_name(pool->pool_md)); 1513 spin_lock_irq(&pool->lock); 1514 pool->low_water_triggered = true; 1515 spin_unlock_irq(&pool->lock); 1516 dm_table_event(pool->ti->table); 1517 } 1518 } 1519 1520 static int alloc_data_block(struct thin_c *tc, dm_block_t *result) 1521 { 1522 int r; 1523 dm_block_t free_blocks; 1524 struct pool *pool = tc->pool; 1525 1526 if (WARN_ON(get_pool_mode(pool) != PM_WRITE)) 1527 return -EINVAL; 1528 1529 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); 1530 if (r) { 1531 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r); 1532 return r; 1533 } 1534 1535 check_low_water_mark(pool, free_blocks); 1536 1537 if (!free_blocks) { 1538 /* 1539 * Try to commit to see if that will free up some 1540 * more space. 1541 */ 1542 r = commit(pool); 1543 if (r) 1544 return r; 1545 1546 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); 1547 if (r) { 1548 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r); 1549 return r; 1550 } 1551 1552 if (!free_blocks) { 1553 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE); 1554 return -ENOSPC; 1555 } 1556 } 1557 1558 r = dm_pool_alloc_data_block(pool->pmd, result); 1559 if (r) { 1560 if (r == -ENOSPC) 1561 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE); 1562 else 1563 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r); 1564 return r; 1565 } 1566 1567 r = dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks); 1568 if (r) { 1569 metadata_operation_failed(pool, "dm_pool_get_free_metadata_block_count", r); 1570 return r; 1571 } 1572 1573 if (!free_blocks) { 1574 /* Let's commit before we use up the metadata reserve. */ 1575 r = commit(pool); 1576 if (r) 1577 return r; 1578 } 1579 1580 return 0; 1581 } 1582 1583 /* 1584 * If we have run out of space, queue bios until the device is 1585 * resumed, presumably after having been reloaded with more space. 1586 */ 1587 static void retry_on_resume(struct bio *bio) 1588 { 1589 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 1590 struct thin_c *tc = h->tc; 1591 1592 spin_lock_irq(&tc->lock); 1593 bio_list_add(&tc->retry_on_resume_list, bio); 1594 spin_unlock_irq(&tc->lock); 1595 } 1596 1597 static blk_status_t should_error_unserviceable_bio(struct pool *pool) 1598 { 1599 enum pool_mode m = get_pool_mode(pool); 1600 1601 switch (m) { 1602 case PM_WRITE: 1603 /* Shouldn't get here */ 1604 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode"); 1605 return BLK_STS_IOERR; 1606 1607 case PM_OUT_OF_DATA_SPACE: 1608 return pool->pf.error_if_no_space ? BLK_STS_NOSPC : 0; 1609 1610 case PM_OUT_OF_METADATA_SPACE: 1611 case PM_READ_ONLY: 1612 case PM_FAIL: 1613 return BLK_STS_IOERR; 1614 default: 1615 /* Shouldn't get here */ 1616 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode"); 1617 return BLK_STS_IOERR; 1618 } 1619 } 1620 1621 static void handle_unserviceable_bio(struct pool *pool, struct bio *bio) 1622 { 1623 blk_status_t error = should_error_unserviceable_bio(pool); 1624 1625 if (error) { 1626 bio->bi_status = error; 1627 bio_endio(bio); 1628 } else 1629 retry_on_resume(bio); 1630 } 1631 1632 static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell) 1633 { 1634 struct bio *bio; 1635 struct bio_list bios; 1636 blk_status_t error; 1637 1638 error = should_error_unserviceable_bio(pool); 1639 if (error) { 1640 cell_error_with_code(pool, cell, error); 1641 return; 1642 } 1643 1644 bio_list_init(&bios); 1645 cell_release(pool, cell, &bios); 1646 1647 while ((bio = bio_list_pop(&bios))) 1648 retry_on_resume(bio); 1649 } 1650 1651 static void process_discard_cell_no_passdown(struct thin_c *tc, 1652 struct dm_bio_prison_cell *virt_cell) 1653 { 1654 struct pool *pool = tc->pool; 1655 struct dm_thin_new_mapping *m = get_next_mapping(pool); 1656 1657 /* 1658 * We don't need to lock the data blocks, since there's no 1659 * passdown. We only lock data blocks for allocation and breaking sharing. 1660 */ 1661 m->tc = tc; 1662 m->virt_begin = virt_cell->key.block_begin; 1663 m->virt_end = virt_cell->key.block_end; 1664 m->cell = virt_cell; 1665 m->bio = virt_cell->holder; 1666 1667 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) 1668 pool->process_prepared_discard(m); 1669 } 1670 1671 static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t end, 1672 struct bio *bio) 1673 { 1674 struct pool *pool = tc->pool; 1675 1676 int r; 1677 bool maybe_shared; 1678 struct dm_cell_key data_key; 1679 struct dm_bio_prison_cell *data_cell; 1680 struct dm_thin_new_mapping *m; 1681 dm_block_t virt_begin, virt_end, data_begin; 1682 1683 while (begin != end) { 1684 r = ensure_next_mapping(pool); 1685 if (r) 1686 /* we did our best */ 1687 return; 1688 1689 r = dm_thin_find_mapped_range(tc->td, begin, end, &virt_begin, &virt_end, 1690 &data_begin, &maybe_shared); 1691 if (r) 1692 /* 1693 * Silently fail, letting any mappings we've 1694 * created complete. 1695 */ 1696 break; 1697 1698 build_key(tc->td, PHYSICAL, data_begin, data_begin + (virt_end - virt_begin), &data_key); 1699 if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) { 1700 /* contention, we'll give up with this range */ 1701 begin = virt_end; 1702 continue; 1703 } 1704 1705 /* 1706 * IO may still be going to the destination block. We must 1707 * quiesce before we can do the removal. 1708 */ 1709 m = get_next_mapping(pool); 1710 m->tc = tc; 1711 m->maybe_shared = maybe_shared; 1712 m->virt_begin = virt_begin; 1713 m->virt_end = virt_end; 1714 m->data_block = data_begin; 1715 m->cell = data_cell; 1716 m->bio = bio; 1717 1718 /* 1719 * The parent bio must not complete before sub discard bios are 1720 * chained to it (see end_discard's bio_chain)! 1721 * 1722 * This per-mapping bi_remaining increment is paired with 1723 * the implicit decrement that occurs via bio_endio() in 1724 * end_discard(). 1725 */ 1726 bio_inc_remaining(bio); 1727 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) 1728 pool->process_prepared_discard(m); 1729 1730 begin = virt_end; 1731 } 1732 } 1733 1734 static void process_discard_cell_passdown(struct thin_c *tc, struct dm_bio_prison_cell *virt_cell) 1735 { 1736 struct bio *bio = virt_cell->holder; 1737 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 1738 1739 /* 1740 * The virt_cell will only get freed once the origin bio completes. 1741 * This means it will remain locked while all the individual 1742 * passdown bios are in flight. 1743 */ 1744 h->cell = virt_cell; 1745 break_up_discard_bio(tc, virt_cell->key.block_begin, virt_cell->key.block_end, bio); 1746 1747 /* 1748 * We complete the bio now, knowing that the bi_remaining field 1749 * will prevent completion until the sub range discards have 1750 * completed. 1751 */ 1752 bio_endio(bio); 1753 } 1754 1755 static void process_discard_bio(struct thin_c *tc, struct bio *bio) 1756 { 1757 dm_block_t begin, end; 1758 struct dm_cell_key virt_key; 1759 struct dm_bio_prison_cell *virt_cell; 1760 1761 get_bio_block_range(tc, bio, &begin, &end); 1762 if (begin == end) { 1763 /* 1764 * The discard covers less than a block. 1765 */ 1766 bio_endio(bio); 1767 return; 1768 } 1769 1770 build_key(tc->td, VIRTUAL, begin, end, &virt_key); 1771 if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) 1772 /* 1773 * Potential starvation issue: We're relying on the 1774 * fs/application being well behaved, and not trying to 1775 * send IO to a region at the same time as discarding it. 1776 * If they do this persistently then it's possible this 1777 * cell will never be granted. 1778 */ 1779 return; 1780 1781 tc->pool->process_discard_cell(tc, virt_cell); 1782 } 1783 1784 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block, 1785 struct dm_cell_key *key, 1786 struct dm_thin_lookup_result *lookup_result, 1787 struct dm_bio_prison_cell *cell) 1788 { 1789 int r; 1790 dm_block_t data_block; 1791 struct pool *pool = tc->pool; 1792 1793 r = alloc_data_block(tc, &data_block); 1794 switch (r) { 1795 case 0: 1796 schedule_internal_copy(tc, block, lookup_result->block, 1797 data_block, cell, bio); 1798 break; 1799 1800 case -ENOSPC: 1801 retry_bios_on_resume(pool, cell); 1802 break; 1803 1804 default: 1805 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d", 1806 __func__, r); 1807 cell_error(pool, cell); 1808 break; 1809 } 1810 } 1811 1812 static void __remap_and_issue_shared_cell(void *context, 1813 struct dm_bio_prison_cell *cell) 1814 { 1815 struct remap_info *info = context; 1816 struct bio *bio; 1817 1818 while ((bio = bio_list_pop(&cell->bios))) { 1819 if (bio_data_dir(bio) == WRITE || op_is_flush(bio->bi_opf) || 1820 bio_op(bio) == REQ_OP_DISCARD) 1821 bio_list_add(&info->defer_bios, bio); 1822 else { 1823 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 1824 1825 h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds); 1826 inc_all_io_entry(info->tc->pool, bio); 1827 bio_list_add(&info->issue_bios, bio); 1828 } 1829 } 1830 } 1831 1832 static void remap_and_issue_shared_cell(struct thin_c *tc, 1833 struct dm_bio_prison_cell *cell, 1834 dm_block_t block) 1835 { 1836 struct bio *bio; 1837 struct remap_info info; 1838 1839 info.tc = tc; 1840 bio_list_init(&info.defer_bios); 1841 bio_list_init(&info.issue_bios); 1842 1843 cell_visit_release(tc->pool, __remap_and_issue_shared_cell, 1844 &info, cell); 1845 1846 while ((bio = bio_list_pop(&info.defer_bios))) 1847 thin_defer_bio(tc, bio); 1848 1849 while ((bio = bio_list_pop(&info.issue_bios))) 1850 remap_and_issue(tc, bio, block); 1851 } 1852 1853 static void process_shared_bio(struct thin_c *tc, struct bio *bio, 1854 dm_block_t block, 1855 struct dm_thin_lookup_result *lookup_result, 1856 struct dm_bio_prison_cell *virt_cell) 1857 { 1858 struct dm_bio_prison_cell *data_cell; 1859 struct pool *pool = tc->pool; 1860 struct dm_cell_key key; 1861 1862 /* 1863 * If cell is already occupied, then sharing is already in the process 1864 * of being broken so we have nothing further to do here. 1865 */ 1866 build_data_key(tc->td, lookup_result->block, &key); 1867 if (bio_detain(pool, &key, bio, &data_cell)) { 1868 cell_defer_no_holder(tc, virt_cell); 1869 return; 1870 } 1871 1872 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) { 1873 break_sharing(tc, bio, block, &key, lookup_result, data_cell); 1874 cell_defer_no_holder(tc, virt_cell); 1875 } else { 1876 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 1877 1878 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds); 1879 inc_all_io_entry(pool, bio); 1880 remap_and_issue(tc, bio, lookup_result->block); 1881 1882 remap_and_issue_shared_cell(tc, data_cell, lookup_result->block); 1883 remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block); 1884 } 1885 } 1886 1887 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block, 1888 struct dm_bio_prison_cell *cell) 1889 { 1890 int r; 1891 dm_block_t data_block; 1892 struct pool *pool = tc->pool; 1893 1894 /* 1895 * Remap empty bios (flushes) immediately, without provisioning. 1896 */ 1897 if (!bio->bi_iter.bi_size) { 1898 inc_all_io_entry(pool, bio); 1899 cell_defer_no_holder(tc, cell); 1900 1901 remap_and_issue(tc, bio, 0); 1902 return; 1903 } 1904 1905 /* 1906 * Fill read bios with zeroes and complete them immediately. 1907 */ 1908 if (bio_data_dir(bio) == READ) { 1909 zero_fill_bio(bio); 1910 cell_defer_no_holder(tc, cell); 1911 bio_endio(bio); 1912 return; 1913 } 1914 1915 r = alloc_data_block(tc, &data_block); 1916 switch (r) { 1917 case 0: 1918 if (tc->origin_dev) 1919 schedule_external_copy(tc, block, data_block, cell, bio); 1920 else 1921 schedule_zero(tc, block, data_block, cell, bio); 1922 break; 1923 1924 case -ENOSPC: 1925 retry_bios_on_resume(pool, cell); 1926 break; 1927 1928 default: 1929 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d", 1930 __func__, r); 1931 cell_error(pool, cell); 1932 break; 1933 } 1934 } 1935 1936 static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) 1937 { 1938 int r; 1939 struct pool *pool = tc->pool; 1940 struct bio *bio = cell->holder; 1941 dm_block_t block = get_bio_block(tc, bio); 1942 struct dm_thin_lookup_result lookup_result; 1943 1944 if (tc->requeue_mode) { 1945 cell_requeue(pool, cell); 1946 return; 1947 } 1948 1949 r = dm_thin_find_block(tc->td, block, 1, &lookup_result); 1950 switch (r) { 1951 case 0: 1952 if (lookup_result.shared) 1953 process_shared_bio(tc, bio, block, &lookup_result, cell); 1954 else { 1955 inc_all_io_entry(pool, bio); 1956 remap_and_issue(tc, bio, lookup_result.block); 1957 inc_remap_and_issue_cell(tc, cell, lookup_result.block); 1958 } 1959 break; 1960 1961 case -ENODATA: 1962 if (bio_data_dir(bio) == READ && tc->origin_dev) { 1963 inc_all_io_entry(pool, bio); 1964 cell_defer_no_holder(tc, cell); 1965 1966 if (bio_end_sector(bio) <= tc->origin_size) 1967 remap_to_origin_and_issue(tc, bio); 1968 1969 else if (bio->bi_iter.bi_sector < tc->origin_size) { 1970 zero_fill_bio(bio); 1971 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT; 1972 remap_to_origin_and_issue(tc, bio); 1973 1974 } else { 1975 zero_fill_bio(bio); 1976 bio_endio(bio); 1977 } 1978 } else 1979 provision_block(tc, bio, block, cell); 1980 break; 1981 1982 default: 1983 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d", 1984 __func__, r); 1985 cell_defer_no_holder(tc, cell); 1986 bio_io_error(bio); 1987 break; 1988 } 1989 } 1990 1991 static void process_bio(struct thin_c *tc, struct bio *bio) 1992 { 1993 struct pool *pool = tc->pool; 1994 dm_block_t block = get_bio_block(tc, bio); 1995 struct dm_bio_prison_cell *cell; 1996 struct dm_cell_key key; 1997 1998 /* 1999 * If cell is already occupied, then the block is already 2000 * being provisioned so we have nothing further to do here. 2001 */ 2002 build_virtual_key(tc->td, block, &key); 2003 if (bio_detain(pool, &key, bio, &cell)) 2004 return; 2005 2006 process_cell(tc, cell); 2007 } 2008 2009 static void __process_bio_read_only(struct thin_c *tc, struct bio *bio, 2010 struct dm_bio_prison_cell *cell) 2011 { 2012 int r; 2013 int rw = bio_data_dir(bio); 2014 dm_block_t block = get_bio_block(tc, bio); 2015 struct dm_thin_lookup_result lookup_result; 2016 2017 r = dm_thin_find_block(tc->td, block, 1, &lookup_result); 2018 switch (r) { 2019 case 0: 2020 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) { 2021 handle_unserviceable_bio(tc->pool, bio); 2022 if (cell) 2023 cell_defer_no_holder(tc, cell); 2024 } else { 2025 inc_all_io_entry(tc->pool, bio); 2026 remap_and_issue(tc, bio, lookup_result.block); 2027 if (cell) 2028 inc_remap_and_issue_cell(tc, cell, lookup_result.block); 2029 } 2030 break; 2031 2032 case -ENODATA: 2033 if (cell) 2034 cell_defer_no_holder(tc, cell); 2035 if (rw != READ) { 2036 handle_unserviceable_bio(tc->pool, bio); 2037 break; 2038 } 2039 2040 if (tc->origin_dev) { 2041 inc_all_io_entry(tc->pool, bio); 2042 remap_to_origin_and_issue(tc, bio); 2043 break; 2044 } 2045 2046 zero_fill_bio(bio); 2047 bio_endio(bio); 2048 break; 2049 2050 default: 2051 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d", 2052 __func__, r); 2053 if (cell) 2054 cell_defer_no_holder(tc, cell); 2055 bio_io_error(bio); 2056 break; 2057 } 2058 } 2059 2060 static void process_bio_read_only(struct thin_c *tc, struct bio *bio) 2061 { 2062 __process_bio_read_only(tc, bio, NULL); 2063 } 2064 2065 static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell) 2066 { 2067 __process_bio_read_only(tc, cell->holder, cell); 2068 } 2069 2070 static void process_bio_success(struct thin_c *tc, struct bio *bio) 2071 { 2072 bio_endio(bio); 2073 } 2074 2075 static void process_bio_fail(struct thin_c *tc, struct bio *bio) 2076 { 2077 bio_io_error(bio); 2078 } 2079 2080 static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell) 2081 { 2082 cell_success(tc->pool, cell); 2083 } 2084 2085 static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell) 2086 { 2087 cell_error(tc->pool, cell); 2088 } 2089 2090 /* 2091 * FIXME: should we also commit due to size of transaction, measured in 2092 * metadata blocks? 2093 */ 2094 static int need_commit_due_to_time(struct pool *pool) 2095 { 2096 return !time_in_range(jiffies, pool->last_commit_jiffies, 2097 pool->last_commit_jiffies + COMMIT_PERIOD); 2098 } 2099 2100 #define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node) 2101 #define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook)) 2102 2103 static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio) 2104 { 2105 struct rb_node **rbp, *parent; 2106 struct dm_thin_endio_hook *pbd; 2107 sector_t bi_sector = bio->bi_iter.bi_sector; 2108 2109 rbp = &tc->sort_bio_list.rb_node; 2110 parent = NULL; 2111 while (*rbp) { 2112 parent = *rbp; 2113 pbd = thin_pbd(parent); 2114 2115 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector) 2116 rbp = &(*rbp)->rb_left; 2117 else 2118 rbp = &(*rbp)->rb_right; 2119 } 2120 2121 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 2122 rb_link_node(&pbd->rb_node, parent, rbp); 2123 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list); 2124 } 2125 2126 static void __extract_sorted_bios(struct thin_c *tc) 2127 { 2128 struct rb_node *node; 2129 struct dm_thin_endio_hook *pbd; 2130 struct bio *bio; 2131 2132 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) { 2133 pbd = thin_pbd(node); 2134 bio = thin_bio(pbd); 2135 2136 bio_list_add(&tc->deferred_bio_list, bio); 2137 rb_erase(&pbd->rb_node, &tc->sort_bio_list); 2138 } 2139 2140 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list)); 2141 } 2142 2143 static void __sort_thin_deferred_bios(struct thin_c *tc) 2144 { 2145 struct bio *bio; 2146 struct bio_list bios; 2147 2148 bio_list_init(&bios); 2149 bio_list_merge(&bios, &tc->deferred_bio_list); 2150 bio_list_init(&tc->deferred_bio_list); 2151 2152 /* Sort deferred_bio_list using rb-tree */ 2153 while ((bio = bio_list_pop(&bios))) 2154 __thin_bio_rb_add(tc, bio); 2155 2156 /* 2157 * Transfer the sorted bios in sort_bio_list back to 2158 * deferred_bio_list to allow lockless submission of 2159 * all bios. 2160 */ 2161 __extract_sorted_bios(tc); 2162 } 2163 2164 static void process_thin_deferred_bios(struct thin_c *tc) 2165 { 2166 struct pool *pool = tc->pool; 2167 struct bio *bio; 2168 struct bio_list bios; 2169 struct blk_plug plug; 2170 unsigned count = 0; 2171 2172 if (tc->requeue_mode) { 2173 error_thin_bio_list(tc, &tc->deferred_bio_list, 2174 BLK_STS_DM_REQUEUE); 2175 return; 2176 } 2177 2178 bio_list_init(&bios); 2179 2180 spin_lock_irq(&tc->lock); 2181 2182 if (bio_list_empty(&tc->deferred_bio_list)) { 2183 spin_unlock_irq(&tc->lock); 2184 return; 2185 } 2186 2187 __sort_thin_deferred_bios(tc); 2188 2189 bio_list_merge(&bios, &tc->deferred_bio_list); 2190 bio_list_init(&tc->deferred_bio_list); 2191 2192 spin_unlock_irq(&tc->lock); 2193 2194 blk_start_plug(&plug); 2195 while ((bio = bio_list_pop(&bios))) { 2196 /* 2197 * If we've got no free new_mapping structs, and processing 2198 * this bio might require one, we pause until there are some 2199 * prepared mappings to process. 2200 */ 2201 if (ensure_next_mapping(pool)) { 2202 spin_lock_irq(&tc->lock); 2203 bio_list_add(&tc->deferred_bio_list, bio); 2204 bio_list_merge(&tc->deferred_bio_list, &bios); 2205 spin_unlock_irq(&tc->lock); 2206 break; 2207 } 2208 2209 if (bio_op(bio) == REQ_OP_DISCARD) 2210 pool->process_discard(tc, bio); 2211 else 2212 pool->process_bio(tc, bio); 2213 2214 if ((count++ & 127) == 0) { 2215 throttle_work_update(&pool->throttle); 2216 dm_pool_issue_prefetches(pool->pmd); 2217 } 2218 } 2219 blk_finish_plug(&plug); 2220 } 2221 2222 static int cmp_cells(const void *lhs, const void *rhs) 2223 { 2224 struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs); 2225 struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs); 2226 2227 BUG_ON(!lhs_cell->holder); 2228 BUG_ON(!rhs_cell->holder); 2229 2230 if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector) 2231 return -1; 2232 2233 if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector) 2234 return 1; 2235 2236 return 0; 2237 } 2238 2239 static unsigned sort_cells(struct pool *pool, struct list_head *cells) 2240 { 2241 unsigned count = 0; 2242 struct dm_bio_prison_cell *cell, *tmp; 2243 2244 list_for_each_entry_safe(cell, tmp, cells, user_list) { 2245 if (count >= CELL_SORT_ARRAY_SIZE) 2246 break; 2247 2248 pool->cell_sort_array[count++] = cell; 2249 list_del(&cell->user_list); 2250 } 2251 2252 sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL); 2253 2254 return count; 2255 } 2256 2257 static void process_thin_deferred_cells(struct thin_c *tc) 2258 { 2259 struct pool *pool = tc->pool; 2260 struct list_head cells; 2261 struct dm_bio_prison_cell *cell; 2262 unsigned i, j, count; 2263 2264 INIT_LIST_HEAD(&cells); 2265 2266 spin_lock_irq(&tc->lock); 2267 list_splice_init(&tc->deferred_cells, &cells); 2268 spin_unlock_irq(&tc->lock); 2269 2270 if (list_empty(&cells)) 2271 return; 2272 2273 do { 2274 count = sort_cells(tc->pool, &cells); 2275 2276 for (i = 0; i < count; i++) { 2277 cell = pool->cell_sort_array[i]; 2278 BUG_ON(!cell->holder); 2279 2280 /* 2281 * If we've got no free new_mapping structs, and processing 2282 * this bio might require one, we pause until there are some 2283 * prepared mappings to process. 2284 */ 2285 if (ensure_next_mapping(pool)) { 2286 for (j = i; j < count; j++) 2287 list_add(&pool->cell_sort_array[j]->user_list, &cells); 2288 2289 spin_lock_irq(&tc->lock); 2290 list_splice(&cells, &tc->deferred_cells); 2291 spin_unlock_irq(&tc->lock); 2292 return; 2293 } 2294 2295 if (bio_op(cell->holder) == REQ_OP_DISCARD) 2296 pool->process_discard_cell(tc, cell); 2297 else 2298 pool->process_cell(tc, cell); 2299 } 2300 } while (!list_empty(&cells)); 2301 } 2302 2303 static void thin_get(struct thin_c *tc); 2304 static void thin_put(struct thin_c *tc); 2305 2306 /* 2307 * We can't hold rcu_read_lock() around code that can block. So we 2308 * find a thin with the rcu lock held; bump a refcount; then drop 2309 * the lock. 2310 */ 2311 static struct thin_c *get_first_thin(struct pool *pool) 2312 { 2313 struct thin_c *tc = NULL; 2314 2315 rcu_read_lock(); 2316 if (!list_empty(&pool->active_thins)) { 2317 tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list); 2318 thin_get(tc); 2319 } 2320 rcu_read_unlock(); 2321 2322 return tc; 2323 } 2324 2325 static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc) 2326 { 2327 struct thin_c *old_tc = tc; 2328 2329 rcu_read_lock(); 2330 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) { 2331 thin_get(tc); 2332 thin_put(old_tc); 2333 rcu_read_unlock(); 2334 return tc; 2335 } 2336 thin_put(old_tc); 2337 rcu_read_unlock(); 2338 2339 return NULL; 2340 } 2341 2342 static void process_deferred_bios(struct pool *pool) 2343 { 2344 struct bio *bio; 2345 struct bio_list bios, bio_completions; 2346 struct thin_c *tc; 2347 2348 tc = get_first_thin(pool); 2349 while (tc) { 2350 process_thin_deferred_cells(tc); 2351 process_thin_deferred_bios(tc); 2352 tc = get_next_thin(pool, tc); 2353 } 2354 2355 /* 2356 * If there are any deferred flush bios, we must commit the metadata 2357 * before issuing them or signaling their completion. 2358 */ 2359 bio_list_init(&bios); 2360 bio_list_init(&bio_completions); 2361 2362 spin_lock_irq(&pool->lock); 2363 bio_list_merge(&bios, &pool->deferred_flush_bios); 2364 bio_list_init(&pool->deferred_flush_bios); 2365 2366 bio_list_merge(&bio_completions, &pool->deferred_flush_completions); 2367 bio_list_init(&pool->deferred_flush_completions); 2368 spin_unlock_irq(&pool->lock); 2369 2370 if (bio_list_empty(&bios) && bio_list_empty(&bio_completions) && 2371 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool))) 2372 return; 2373 2374 if (commit(pool)) { 2375 bio_list_merge(&bios, &bio_completions); 2376 2377 while ((bio = bio_list_pop(&bios))) 2378 bio_io_error(bio); 2379 return; 2380 } 2381 pool->last_commit_jiffies = jiffies; 2382 2383 while ((bio = bio_list_pop(&bio_completions))) 2384 bio_endio(bio); 2385 2386 while ((bio = bio_list_pop(&bios))) 2387 generic_make_request(bio); 2388 } 2389 2390 static void do_worker(struct work_struct *ws) 2391 { 2392 struct pool *pool = container_of(ws, struct pool, worker); 2393 2394 throttle_work_start(&pool->throttle); 2395 dm_pool_issue_prefetches(pool->pmd); 2396 throttle_work_update(&pool->throttle); 2397 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping); 2398 throttle_work_update(&pool->throttle); 2399 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard); 2400 throttle_work_update(&pool->throttle); 2401 process_prepared(pool, &pool->prepared_discards_pt2, &pool->process_prepared_discard_pt2); 2402 throttle_work_update(&pool->throttle); 2403 process_deferred_bios(pool); 2404 throttle_work_complete(&pool->throttle); 2405 } 2406 2407 /* 2408 * We want to commit periodically so that not too much 2409 * unwritten data builds up. 2410 */ 2411 static void do_waker(struct work_struct *ws) 2412 { 2413 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker); 2414 wake_worker(pool); 2415 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD); 2416 } 2417 2418 /* 2419 * We're holding onto IO to allow userland time to react. After the 2420 * timeout either the pool will have been resized (and thus back in 2421 * PM_WRITE mode), or we degrade to PM_OUT_OF_DATA_SPACE w/ error_if_no_space. 2422 */ 2423 static void do_no_space_timeout(struct work_struct *ws) 2424 { 2425 struct pool *pool = container_of(to_delayed_work(ws), struct pool, 2426 no_space_timeout); 2427 2428 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) { 2429 pool->pf.error_if_no_space = true; 2430 notify_of_pool_mode_change(pool); 2431 error_retry_list_with_code(pool, BLK_STS_NOSPC); 2432 } 2433 } 2434 2435 /*----------------------------------------------------------------*/ 2436 2437 struct pool_work { 2438 struct work_struct worker; 2439 struct completion complete; 2440 }; 2441 2442 static struct pool_work *to_pool_work(struct work_struct *ws) 2443 { 2444 return container_of(ws, struct pool_work, worker); 2445 } 2446 2447 static void pool_work_complete(struct pool_work *pw) 2448 { 2449 complete(&pw->complete); 2450 } 2451 2452 static void pool_work_wait(struct pool_work *pw, struct pool *pool, 2453 void (*fn)(struct work_struct *)) 2454 { 2455 INIT_WORK_ONSTACK(&pw->worker, fn); 2456 init_completion(&pw->complete); 2457 queue_work(pool->wq, &pw->worker); 2458 wait_for_completion(&pw->complete); 2459 } 2460 2461 /*----------------------------------------------------------------*/ 2462 2463 struct noflush_work { 2464 struct pool_work pw; 2465 struct thin_c *tc; 2466 }; 2467 2468 static struct noflush_work *to_noflush(struct work_struct *ws) 2469 { 2470 return container_of(to_pool_work(ws), struct noflush_work, pw); 2471 } 2472 2473 static void do_noflush_start(struct work_struct *ws) 2474 { 2475 struct noflush_work *w = to_noflush(ws); 2476 w->tc->requeue_mode = true; 2477 requeue_io(w->tc); 2478 pool_work_complete(&w->pw); 2479 } 2480 2481 static void do_noflush_stop(struct work_struct *ws) 2482 { 2483 struct noflush_work *w = to_noflush(ws); 2484 w->tc->requeue_mode = false; 2485 pool_work_complete(&w->pw); 2486 } 2487 2488 static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *)) 2489 { 2490 struct noflush_work w; 2491 2492 w.tc = tc; 2493 pool_work_wait(&w.pw, tc->pool, fn); 2494 } 2495 2496 /*----------------------------------------------------------------*/ 2497 2498 static bool passdown_enabled(struct pool_c *pt) 2499 { 2500 return pt->adjusted_pf.discard_passdown; 2501 } 2502 2503 static void set_discard_callbacks(struct pool *pool) 2504 { 2505 struct pool_c *pt = pool->ti->private; 2506 2507 if (passdown_enabled(pt)) { 2508 pool->process_discard_cell = process_discard_cell_passdown; 2509 pool->process_prepared_discard = process_prepared_discard_passdown_pt1; 2510 pool->process_prepared_discard_pt2 = process_prepared_discard_passdown_pt2; 2511 } else { 2512 pool->process_discard_cell = process_discard_cell_no_passdown; 2513 pool->process_prepared_discard = process_prepared_discard_no_passdown; 2514 } 2515 } 2516 2517 static void set_pool_mode(struct pool *pool, enum pool_mode new_mode) 2518 { 2519 struct pool_c *pt = pool->ti->private; 2520 bool needs_check = dm_pool_metadata_needs_check(pool->pmd); 2521 enum pool_mode old_mode = get_pool_mode(pool); 2522 unsigned long no_space_timeout = READ_ONCE(no_space_timeout_secs) * HZ; 2523 2524 /* 2525 * Never allow the pool to transition to PM_WRITE mode if user 2526 * intervention is required to verify metadata and data consistency. 2527 */ 2528 if (new_mode == PM_WRITE && needs_check) { 2529 DMERR("%s: unable to switch pool to write mode until repaired.", 2530 dm_device_name(pool->pool_md)); 2531 if (old_mode != new_mode) 2532 new_mode = old_mode; 2533 else 2534 new_mode = PM_READ_ONLY; 2535 } 2536 /* 2537 * If we were in PM_FAIL mode, rollback of metadata failed. We're 2538 * not going to recover without a thin_repair. So we never let the 2539 * pool move out of the old mode. 2540 */ 2541 if (old_mode == PM_FAIL) 2542 new_mode = old_mode; 2543 2544 switch (new_mode) { 2545 case PM_FAIL: 2546 dm_pool_metadata_read_only(pool->pmd); 2547 pool->process_bio = process_bio_fail; 2548 pool->process_discard = process_bio_fail; 2549 pool->process_cell = process_cell_fail; 2550 pool->process_discard_cell = process_cell_fail; 2551 pool->process_prepared_mapping = process_prepared_mapping_fail; 2552 pool->process_prepared_discard = process_prepared_discard_fail; 2553 2554 error_retry_list(pool); 2555 break; 2556 2557 case PM_OUT_OF_METADATA_SPACE: 2558 case PM_READ_ONLY: 2559 dm_pool_metadata_read_only(pool->pmd); 2560 pool->process_bio = process_bio_read_only; 2561 pool->process_discard = process_bio_success; 2562 pool->process_cell = process_cell_read_only; 2563 pool->process_discard_cell = process_cell_success; 2564 pool->process_prepared_mapping = process_prepared_mapping_fail; 2565 pool->process_prepared_discard = process_prepared_discard_success; 2566 2567 error_retry_list(pool); 2568 break; 2569 2570 case PM_OUT_OF_DATA_SPACE: 2571 /* 2572 * Ideally we'd never hit this state; the low water mark 2573 * would trigger userland to extend the pool before we 2574 * completely run out of data space. However, many small 2575 * IOs to unprovisioned space can consume data space at an 2576 * alarming rate. Adjust your low water mark if you're 2577 * frequently seeing this mode. 2578 */ 2579 pool->out_of_data_space = true; 2580 pool->process_bio = process_bio_read_only; 2581 pool->process_discard = process_discard_bio; 2582 pool->process_cell = process_cell_read_only; 2583 pool->process_prepared_mapping = process_prepared_mapping; 2584 set_discard_callbacks(pool); 2585 2586 if (!pool->pf.error_if_no_space && no_space_timeout) 2587 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout); 2588 break; 2589 2590 case PM_WRITE: 2591 if (old_mode == PM_OUT_OF_DATA_SPACE) 2592 cancel_delayed_work_sync(&pool->no_space_timeout); 2593 pool->out_of_data_space = false; 2594 pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space; 2595 dm_pool_metadata_read_write(pool->pmd); 2596 pool->process_bio = process_bio; 2597 pool->process_discard = process_discard_bio; 2598 pool->process_cell = process_cell; 2599 pool->process_prepared_mapping = process_prepared_mapping; 2600 set_discard_callbacks(pool); 2601 break; 2602 } 2603 2604 pool->pf.mode = new_mode; 2605 /* 2606 * The pool mode may have changed, sync it so bind_control_target() 2607 * doesn't cause an unexpected mode transition on resume. 2608 */ 2609 pt->adjusted_pf.mode = new_mode; 2610 2611 if (old_mode != new_mode) 2612 notify_of_pool_mode_change(pool); 2613 } 2614 2615 static void abort_transaction(struct pool *pool) 2616 { 2617 const char *dev_name = dm_device_name(pool->pool_md); 2618 2619 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name); 2620 if (dm_pool_abort_metadata(pool->pmd)) { 2621 DMERR("%s: failed to abort metadata transaction", dev_name); 2622 set_pool_mode(pool, PM_FAIL); 2623 } 2624 2625 if (dm_pool_metadata_set_needs_check(pool->pmd)) { 2626 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name); 2627 set_pool_mode(pool, PM_FAIL); 2628 } 2629 } 2630 2631 static void metadata_operation_failed(struct pool *pool, const char *op, int r) 2632 { 2633 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d", 2634 dm_device_name(pool->pool_md), op, r); 2635 2636 abort_transaction(pool); 2637 set_pool_mode(pool, PM_READ_ONLY); 2638 } 2639 2640 /*----------------------------------------------------------------*/ 2641 2642 /* 2643 * Mapping functions. 2644 */ 2645 2646 /* 2647 * Called only while mapping a thin bio to hand it over to the workqueue. 2648 */ 2649 static void thin_defer_bio(struct thin_c *tc, struct bio *bio) 2650 { 2651 struct pool *pool = tc->pool; 2652 2653 spin_lock_irq(&tc->lock); 2654 bio_list_add(&tc->deferred_bio_list, bio); 2655 spin_unlock_irq(&tc->lock); 2656 2657 wake_worker(pool); 2658 } 2659 2660 static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio) 2661 { 2662 struct pool *pool = tc->pool; 2663 2664 throttle_lock(&pool->throttle); 2665 thin_defer_bio(tc, bio); 2666 throttle_unlock(&pool->throttle); 2667 } 2668 2669 static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) 2670 { 2671 struct pool *pool = tc->pool; 2672 2673 throttle_lock(&pool->throttle); 2674 spin_lock_irq(&tc->lock); 2675 list_add_tail(&cell->user_list, &tc->deferred_cells); 2676 spin_unlock_irq(&tc->lock); 2677 throttle_unlock(&pool->throttle); 2678 2679 wake_worker(pool); 2680 } 2681 2682 static void thin_hook_bio(struct thin_c *tc, struct bio *bio) 2683 { 2684 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 2685 2686 h->tc = tc; 2687 h->shared_read_entry = NULL; 2688 h->all_io_entry = NULL; 2689 h->overwrite_mapping = NULL; 2690 h->cell = NULL; 2691 } 2692 2693 /* 2694 * Non-blocking function called from the thin target's map function. 2695 */ 2696 static int thin_bio_map(struct dm_target *ti, struct bio *bio) 2697 { 2698 int r; 2699 struct thin_c *tc = ti->private; 2700 dm_block_t block = get_bio_block(tc, bio); 2701 struct dm_thin_device *td = tc->td; 2702 struct dm_thin_lookup_result result; 2703 struct dm_bio_prison_cell *virt_cell, *data_cell; 2704 struct dm_cell_key key; 2705 2706 thin_hook_bio(tc, bio); 2707 2708 if (tc->requeue_mode) { 2709 bio->bi_status = BLK_STS_DM_REQUEUE; 2710 bio_endio(bio); 2711 return DM_MAPIO_SUBMITTED; 2712 } 2713 2714 if (get_pool_mode(tc->pool) == PM_FAIL) { 2715 bio_io_error(bio); 2716 return DM_MAPIO_SUBMITTED; 2717 } 2718 2719 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) { 2720 thin_defer_bio_with_throttle(tc, bio); 2721 return DM_MAPIO_SUBMITTED; 2722 } 2723 2724 /* 2725 * We must hold the virtual cell before doing the lookup, otherwise 2726 * there's a race with discard. 2727 */ 2728 build_virtual_key(tc->td, block, &key); 2729 if (bio_detain(tc->pool, &key, bio, &virt_cell)) 2730 return DM_MAPIO_SUBMITTED; 2731 2732 r = dm_thin_find_block(td, block, 0, &result); 2733 2734 /* 2735 * Note that we defer readahead too. 2736 */ 2737 switch (r) { 2738 case 0: 2739 if (unlikely(result.shared)) { 2740 /* 2741 * We have a race condition here between the 2742 * result.shared value returned by the lookup and 2743 * snapshot creation, which may cause new 2744 * sharing. 2745 * 2746 * To avoid this always quiesce the origin before 2747 * taking the snap. You want to do this anyway to 2748 * ensure a consistent application view 2749 * (i.e. lockfs). 2750 * 2751 * More distant ancestors are irrelevant. The 2752 * shared flag will be set in their case. 2753 */ 2754 thin_defer_cell(tc, virt_cell); 2755 return DM_MAPIO_SUBMITTED; 2756 } 2757 2758 build_data_key(tc->td, result.block, &key); 2759 if (bio_detain(tc->pool, &key, bio, &data_cell)) { 2760 cell_defer_no_holder(tc, virt_cell); 2761 return DM_MAPIO_SUBMITTED; 2762 } 2763 2764 inc_all_io_entry(tc->pool, bio); 2765 cell_defer_no_holder(tc, data_cell); 2766 cell_defer_no_holder(tc, virt_cell); 2767 2768 remap(tc, bio, result.block); 2769 return DM_MAPIO_REMAPPED; 2770 2771 case -ENODATA: 2772 case -EWOULDBLOCK: 2773 thin_defer_cell(tc, virt_cell); 2774 return DM_MAPIO_SUBMITTED; 2775 2776 default: 2777 /* 2778 * Must always call bio_io_error on failure. 2779 * dm_thin_find_block can fail with -EINVAL if the 2780 * pool is switched to fail-io mode. 2781 */ 2782 bio_io_error(bio); 2783 cell_defer_no_holder(tc, virt_cell); 2784 return DM_MAPIO_SUBMITTED; 2785 } 2786 } 2787 2788 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits) 2789 { 2790 struct pool_c *pt = container_of(cb, struct pool_c, callbacks); 2791 struct request_queue *q; 2792 2793 if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE) 2794 return 1; 2795 2796 q = bdev_get_queue(pt->data_dev->bdev); 2797 return bdi_congested(q->backing_dev_info, bdi_bits); 2798 } 2799 2800 static void requeue_bios(struct pool *pool) 2801 { 2802 struct thin_c *tc; 2803 2804 rcu_read_lock(); 2805 list_for_each_entry_rcu(tc, &pool->active_thins, list) { 2806 spin_lock_irq(&tc->lock); 2807 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list); 2808 bio_list_init(&tc->retry_on_resume_list); 2809 spin_unlock_irq(&tc->lock); 2810 } 2811 rcu_read_unlock(); 2812 } 2813 2814 /*---------------------------------------------------------------- 2815 * Binding of control targets to a pool object 2816 *--------------------------------------------------------------*/ 2817 static bool data_dev_supports_discard(struct pool_c *pt) 2818 { 2819 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); 2820 2821 return q && blk_queue_discard(q); 2822 } 2823 2824 static bool is_factor(sector_t block_size, uint32_t n) 2825 { 2826 return !sector_div(block_size, n); 2827 } 2828 2829 /* 2830 * If discard_passdown was enabled verify that the data device 2831 * supports discards. Disable discard_passdown if not. 2832 */ 2833 static void disable_passdown_if_not_supported(struct pool_c *pt) 2834 { 2835 struct pool *pool = pt->pool; 2836 struct block_device *data_bdev = pt->data_dev->bdev; 2837 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits; 2838 const char *reason = NULL; 2839 char buf[BDEVNAME_SIZE]; 2840 2841 if (!pt->adjusted_pf.discard_passdown) 2842 return; 2843 2844 if (!data_dev_supports_discard(pt)) 2845 reason = "discard unsupported"; 2846 2847 else if (data_limits->max_discard_sectors < pool->sectors_per_block) 2848 reason = "max discard sectors smaller than a block"; 2849 2850 if (reason) { 2851 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason); 2852 pt->adjusted_pf.discard_passdown = false; 2853 } 2854 } 2855 2856 static int bind_control_target(struct pool *pool, struct dm_target *ti) 2857 { 2858 struct pool_c *pt = ti->private; 2859 2860 /* 2861 * We want to make sure that a pool in PM_FAIL mode is never upgraded. 2862 */ 2863 enum pool_mode old_mode = get_pool_mode(pool); 2864 enum pool_mode new_mode = pt->adjusted_pf.mode; 2865 2866 /* 2867 * Don't change the pool's mode until set_pool_mode() below. 2868 * Otherwise the pool's process_* function pointers may 2869 * not match the desired pool mode. 2870 */ 2871 pt->adjusted_pf.mode = old_mode; 2872 2873 pool->ti = ti; 2874 pool->pf = pt->adjusted_pf; 2875 pool->low_water_blocks = pt->low_water_blocks; 2876 2877 set_pool_mode(pool, new_mode); 2878 2879 return 0; 2880 } 2881 2882 static void unbind_control_target(struct pool *pool, struct dm_target *ti) 2883 { 2884 if (pool->ti == ti) 2885 pool->ti = NULL; 2886 } 2887 2888 /*---------------------------------------------------------------- 2889 * Pool creation 2890 *--------------------------------------------------------------*/ 2891 /* Initialize pool features. */ 2892 static void pool_features_init(struct pool_features *pf) 2893 { 2894 pf->mode = PM_WRITE; 2895 pf->zero_new_blocks = true; 2896 pf->discard_enabled = true; 2897 pf->discard_passdown = true; 2898 pf->error_if_no_space = false; 2899 } 2900 2901 static void __pool_destroy(struct pool *pool) 2902 { 2903 __pool_table_remove(pool); 2904 2905 vfree(pool->cell_sort_array); 2906 if (dm_pool_metadata_close(pool->pmd) < 0) 2907 DMWARN("%s: dm_pool_metadata_close() failed.", __func__); 2908 2909 dm_bio_prison_destroy(pool->prison); 2910 dm_kcopyd_client_destroy(pool->copier); 2911 2912 if (pool->wq) 2913 destroy_workqueue(pool->wq); 2914 2915 if (pool->next_mapping) 2916 mempool_free(pool->next_mapping, &pool->mapping_pool); 2917 mempool_exit(&pool->mapping_pool); 2918 dm_deferred_set_destroy(pool->shared_read_ds); 2919 dm_deferred_set_destroy(pool->all_io_ds); 2920 kfree(pool); 2921 } 2922 2923 static struct kmem_cache *_new_mapping_cache; 2924 2925 static struct pool *pool_create(struct mapped_device *pool_md, 2926 struct block_device *metadata_dev, 2927 unsigned long block_size, 2928 int read_only, char **error) 2929 { 2930 int r; 2931 void *err_p; 2932 struct pool *pool; 2933 struct dm_pool_metadata *pmd; 2934 bool format_device = read_only ? false : true; 2935 2936 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device); 2937 if (IS_ERR(pmd)) { 2938 *error = "Error creating metadata object"; 2939 return (struct pool *)pmd; 2940 } 2941 2942 pool = kzalloc(sizeof(*pool), GFP_KERNEL); 2943 if (!pool) { 2944 *error = "Error allocating memory for pool"; 2945 err_p = ERR_PTR(-ENOMEM); 2946 goto bad_pool; 2947 } 2948 2949 pool->pmd = pmd; 2950 pool->sectors_per_block = block_size; 2951 if (block_size & (block_size - 1)) 2952 pool->sectors_per_block_shift = -1; 2953 else 2954 pool->sectors_per_block_shift = __ffs(block_size); 2955 pool->low_water_blocks = 0; 2956 pool_features_init(&pool->pf); 2957 pool->prison = dm_bio_prison_create(); 2958 if (!pool->prison) { 2959 *error = "Error creating pool's bio prison"; 2960 err_p = ERR_PTR(-ENOMEM); 2961 goto bad_prison; 2962 } 2963 2964 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); 2965 if (IS_ERR(pool->copier)) { 2966 r = PTR_ERR(pool->copier); 2967 *error = "Error creating pool's kcopyd client"; 2968 err_p = ERR_PTR(r); 2969 goto bad_kcopyd_client; 2970 } 2971 2972 /* 2973 * Create singlethreaded workqueue that will service all devices 2974 * that use this metadata. 2975 */ 2976 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); 2977 if (!pool->wq) { 2978 *error = "Error creating pool's workqueue"; 2979 err_p = ERR_PTR(-ENOMEM); 2980 goto bad_wq; 2981 } 2982 2983 throttle_init(&pool->throttle); 2984 INIT_WORK(&pool->worker, do_worker); 2985 INIT_DELAYED_WORK(&pool->waker, do_waker); 2986 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout); 2987 spin_lock_init(&pool->lock); 2988 bio_list_init(&pool->deferred_flush_bios); 2989 bio_list_init(&pool->deferred_flush_completions); 2990 INIT_LIST_HEAD(&pool->prepared_mappings); 2991 INIT_LIST_HEAD(&pool->prepared_discards); 2992 INIT_LIST_HEAD(&pool->prepared_discards_pt2); 2993 INIT_LIST_HEAD(&pool->active_thins); 2994 pool->low_water_triggered = false; 2995 pool->suspended = true; 2996 pool->out_of_data_space = false; 2997 2998 pool->shared_read_ds = dm_deferred_set_create(); 2999 if (!pool->shared_read_ds) { 3000 *error = "Error creating pool's shared read deferred set"; 3001 err_p = ERR_PTR(-ENOMEM); 3002 goto bad_shared_read_ds; 3003 } 3004 3005 pool->all_io_ds = dm_deferred_set_create(); 3006 if (!pool->all_io_ds) { 3007 *error = "Error creating pool's all io deferred set"; 3008 err_p = ERR_PTR(-ENOMEM); 3009 goto bad_all_io_ds; 3010 } 3011 3012 pool->next_mapping = NULL; 3013 r = mempool_init_slab_pool(&pool->mapping_pool, MAPPING_POOL_SIZE, 3014 _new_mapping_cache); 3015 if (r) { 3016 *error = "Error creating pool's mapping mempool"; 3017 err_p = ERR_PTR(r); 3018 goto bad_mapping_pool; 3019 } 3020 3021 pool->cell_sort_array = 3022 vmalloc(array_size(CELL_SORT_ARRAY_SIZE, 3023 sizeof(*pool->cell_sort_array))); 3024 if (!pool->cell_sort_array) { 3025 *error = "Error allocating cell sort array"; 3026 err_p = ERR_PTR(-ENOMEM); 3027 goto bad_sort_array; 3028 } 3029 3030 pool->ref_count = 1; 3031 pool->last_commit_jiffies = jiffies; 3032 pool->pool_md = pool_md; 3033 pool->md_dev = metadata_dev; 3034 __pool_table_insert(pool); 3035 3036 return pool; 3037 3038 bad_sort_array: 3039 mempool_exit(&pool->mapping_pool); 3040 bad_mapping_pool: 3041 dm_deferred_set_destroy(pool->all_io_ds); 3042 bad_all_io_ds: 3043 dm_deferred_set_destroy(pool->shared_read_ds); 3044 bad_shared_read_ds: 3045 destroy_workqueue(pool->wq); 3046 bad_wq: 3047 dm_kcopyd_client_destroy(pool->copier); 3048 bad_kcopyd_client: 3049 dm_bio_prison_destroy(pool->prison); 3050 bad_prison: 3051 kfree(pool); 3052 bad_pool: 3053 if (dm_pool_metadata_close(pmd)) 3054 DMWARN("%s: dm_pool_metadata_close() failed.", __func__); 3055 3056 return err_p; 3057 } 3058 3059 static void __pool_inc(struct pool *pool) 3060 { 3061 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); 3062 pool->ref_count++; 3063 } 3064 3065 static void __pool_dec(struct pool *pool) 3066 { 3067 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); 3068 BUG_ON(!pool->ref_count); 3069 if (!--pool->ref_count) 3070 __pool_destroy(pool); 3071 } 3072 3073 static struct pool *__pool_find(struct mapped_device *pool_md, 3074 struct block_device *metadata_dev, 3075 unsigned long block_size, int read_only, 3076 char **error, int *created) 3077 { 3078 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev); 3079 3080 if (pool) { 3081 if (pool->pool_md != pool_md) { 3082 *error = "metadata device already in use by a pool"; 3083 return ERR_PTR(-EBUSY); 3084 } 3085 __pool_inc(pool); 3086 3087 } else { 3088 pool = __pool_table_lookup(pool_md); 3089 if (pool) { 3090 if (pool->md_dev != metadata_dev) { 3091 *error = "different pool cannot replace a pool"; 3092 return ERR_PTR(-EINVAL); 3093 } 3094 __pool_inc(pool); 3095 3096 } else { 3097 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error); 3098 *created = 1; 3099 } 3100 } 3101 3102 return pool; 3103 } 3104 3105 /*---------------------------------------------------------------- 3106 * Pool target methods 3107 *--------------------------------------------------------------*/ 3108 static void pool_dtr(struct dm_target *ti) 3109 { 3110 struct pool_c *pt = ti->private; 3111 3112 mutex_lock(&dm_thin_pool_table.mutex); 3113 3114 unbind_control_target(pt->pool, ti); 3115 __pool_dec(pt->pool); 3116 dm_put_device(ti, pt->metadata_dev); 3117 dm_put_device(ti, pt->data_dev); 3118 kfree(pt); 3119 3120 mutex_unlock(&dm_thin_pool_table.mutex); 3121 } 3122 3123 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf, 3124 struct dm_target *ti) 3125 { 3126 int r; 3127 unsigned argc; 3128 const char *arg_name; 3129 3130 static const struct dm_arg _args[] = { 3131 {0, 4, "Invalid number of pool feature arguments"}, 3132 }; 3133 3134 /* 3135 * No feature arguments supplied. 3136 */ 3137 if (!as->argc) 3138 return 0; 3139 3140 r = dm_read_arg_group(_args, as, &argc, &ti->error); 3141 if (r) 3142 return -EINVAL; 3143 3144 while (argc && !r) { 3145 arg_name = dm_shift_arg(as); 3146 argc--; 3147 3148 if (!strcasecmp(arg_name, "skip_block_zeroing")) 3149 pf->zero_new_blocks = false; 3150 3151 else if (!strcasecmp(arg_name, "ignore_discard")) 3152 pf->discard_enabled = false; 3153 3154 else if (!strcasecmp(arg_name, "no_discard_passdown")) 3155 pf->discard_passdown = false; 3156 3157 else if (!strcasecmp(arg_name, "read_only")) 3158 pf->mode = PM_READ_ONLY; 3159 3160 else if (!strcasecmp(arg_name, "error_if_no_space")) 3161 pf->error_if_no_space = true; 3162 3163 else { 3164 ti->error = "Unrecognised pool feature requested"; 3165 r = -EINVAL; 3166 break; 3167 } 3168 } 3169 3170 return r; 3171 } 3172 3173 static void metadata_low_callback(void *context) 3174 { 3175 struct pool *pool = context; 3176 3177 DMWARN("%s: reached low water mark for metadata device: sending event.", 3178 dm_device_name(pool->pool_md)); 3179 3180 dm_table_event(pool->ti->table); 3181 } 3182 3183 static sector_t get_dev_size(struct block_device *bdev) 3184 { 3185 return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT; 3186 } 3187 3188 static void warn_if_metadata_device_too_big(struct block_device *bdev) 3189 { 3190 sector_t metadata_dev_size = get_dev_size(bdev); 3191 char buffer[BDEVNAME_SIZE]; 3192 3193 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING) 3194 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", 3195 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS); 3196 } 3197 3198 static sector_t get_metadata_dev_size(struct block_device *bdev) 3199 { 3200 sector_t metadata_dev_size = get_dev_size(bdev); 3201 3202 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS) 3203 metadata_dev_size = THIN_METADATA_MAX_SECTORS; 3204 3205 return metadata_dev_size; 3206 } 3207 3208 static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev) 3209 { 3210 sector_t metadata_dev_size = get_metadata_dev_size(bdev); 3211 3212 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE); 3213 3214 return metadata_dev_size; 3215 } 3216 3217 /* 3218 * When a metadata threshold is crossed a dm event is triggered, and 3219 * userland should respond by growing the metadata device. We could let 3220 * userland set the threshold, like we do with the data threshold, but I'm 3221 * not sure they know enough to do this well. 3222 */ 3223 static dm_block_t calc_metadata_threshold(struct pool_c *pt) 3224 { 3225 /* 3226 * 4M is ample for all ops with the possible exception of thin 3227 * device deletion which is harmless if it fails (just retry the 3228 * delete after you've grown the device). 3229 */ 3230 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4; 3231 return min((dm_block_t)1024ULL /* 4M */, quarter); 3232 } 3233 3234 /* 3235 * thin-pool <metadata dev> <data dev> 3236 * <data block size (sectors)> 3237 * <low water mark (blocks)> 3238 * [<#feature args> [<arg>]*] 3239 * 3240 * Optional feature arguments are: 3241 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks. 3242 * ignore_discard: disable discard 3243 * no_discard_passdown: don't pass discards down to the data device 3244 * read_only: Don't allow any changes to be made to the pool metadata. 3245 * error_if_no_space: error IOs, instead of queueing, if no space. 3246 */ 3247 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv) 3248 { 3249 int r, pool_created = 0; 3250 struct pool_c *pt; 3251 struct pool *pool; 3252 struct pool_features pf; 3253 struct dm_arg_set as; 3254 struct dm_dev *data_dev; 3255 unsigned long block_size; 3256 dm_block_t low_water_blocks; 3257 struct dm_dev *metadata_dev; 3258 fmode_t metadata_mode; 3259 3260 /* 3261 * FIXME Remove validation from scope of lock. 3262 */ 3263 mutex_lock(&dm_thin_pool_table.mutex); 3264 3265 if (argc < 4) { 3266 ti->error = "Invalid argument count"; 3267 r = -EINVAL; 3268 goto out_unlock; 3269 } 3270 3271 as.argc = argc; 3272 as.argv = argv; 3273 3274 /* make sure metadata and data are different devices */ 3275 if (!strcmp(argv[0], argv[1])) { 3276 ti->error = "Error setting metadata or data device"; 3277 r = -EINVAL; 3278 goto out_unlock; 3279 } 3280 3281 /* 3282 * Set default pool features. 3283 */ 3284 pool_features_init(&pf); 3285 3286 dm_consume_args(&as, 4); 3287 r = parse_pool_features(&as, &pf, ti); 3288 if (r) 3289 goto out_unlock; 3290 3291 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE); 3292 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev); 3293 if (r) { 3294 ti->error = "Error opening metadata block device"; 3295 goto out_unlock; 3296 } 3297 warn_if_metadata_device_too_big(metadata_dev->bdev); 3298 3299 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev); 3300 if (r) { 3301 ti->error = "Error getting data device"; 3302 goto out_metadata; 3303 } 3304 3305 if (kstrtoul(argv[2], 10, &block_size) || !block_size || 3306 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || 3307 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || 3308 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { 3309 ti->error = "Invalid block size"; 3310 r = -EINVAL; 3311 goto out; 3312 } 3313 3314 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) { 3315 ti->error = "Invalid low water mark"; 3316 r = -EINVAL; 3317 goto out; 3318 } 3319 3320 pt = kzalloc(sizeof(*pt), GFP_KERNEL); 3321 if (!pt) { 3322 r = -ENOMEM; 3323 goto out; 3324 } 3325 3326 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, 3327 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created); 3328 if (IS_ERR(pool)) { 3329 r = PTR_ERR(pool); 3330 goto out_free_pt; 3331 } 3332 3333 /* 3334 * 'pool_created' reflects whether this is the first table load. 3335 * Top level discard support is not allowed to be changed after 3336 * initial load. This would require a pool reload to trigger thin 3337 * device changes. 3338 */ 3339 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) { 3340 ti->error = "Discard support cannot be disabled once enabled"; 3341 r = -EINVAL; 3342 goto out_flags_changed; 3343 } 3344 3345 pt->pool = pool; 3346 pt->ti = ti; 3347 pt->metadata_dev = metadata_dev; 3348 pt->data_dev = data_dev; 3349 pt->low_water_blocks = low_water_blocks; 3350 pt->adjusted_pf = pt->requested_pf = pf; 3351 ti->num_flush_bios = 1; 3352 3353 /* 3354 * Only need to enable discards if the pool should pass 3355 * them down to the data device. The thin device's discard 3356 * processing will cause mappings to be removed from the btree. 3357 */ 3358 if (pf.discard_enabled && pf.discard_passdown) { 3359 ti->num_discard_bios = 1; 3360 3361 /* 3362 * Setting 'discards_supported' circumvents the normal 3363 * stacking of discard limits (this keeps the pool and 3364 * thin devices' discard limits consistent). 3365 */ 3366 ti->discards_supported = true; 3367 } 3368 ti->private = pt; 3369 3370 r = dm_pool_register_metadata_threshold(pt->pool->pmd, 3371 calc_metadata_threshold(pt), 3372 metadata_low_callback, 3373 pool); 3374 if (r) 3375 goto out_flags_changed; 3376 3377 pt->callbacks.congested_fn = pool_is_congested; 3378 dm_table_add_target_callbacks(ti->table, &pt->callbacks); 3379 3380 mutex_unlock(&dm_thin_pool_table.mutex); 3381 3382 return 0; 3383 3384 out_flags_changed: 3385 __pool_dec(pool); 3386 out_free_pt: 3387 kfree(pt); 3388 out: 3389 dm_put_device(ti, data_dev); 3390 out_metadata: 3391 dm_put_device(ti, metadata_dev); 3392 out_unlock: 3393 mutex_unlock(&dm_thin_pool_table.mutex); 3394 3395 return r; 3396 } 3397 3398 static int pool_map(struct dm_target *ti, struct bio *bio) 3399 { 3400 int r; 3401 struct pool_c *pt = ti->private; 3402 struct pool *pool = pt->pool; 3403 3404 /* 3405 * As this is a singleton target, ti->begin is always zero. 3406 */ 3407 spin_lock_irq(&pool->lock); 3408 bio_set_dev(bio, pt->data_dev->bdev); 3409 r = DM_MAPIO_REMAPPED; 3410 spin_unlock_irq(&pool->lock); 3411 3412 return r; 3413 } 3414 3415 static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit) 3416 { 3417 int r; 3418 struct pool_c *pt = ti->private; 3419 struct pool *pool = pt->pool; 3420 sector_t data_size = ti->len; 3421 dm_block_t sb_data_size; 3422 3423 *need_commit = false; 3424 3425 (void) sector_div(data_size, pool->sectors_per_block); 3426 3427 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size); 3428 if (r) { 3429 DMERR("%s: failed to retrieve data device size", 3430 dm_device_name(pool->pool_md)); 3431 return r; 3432 } 3433 3434 if (data_size < sb_data_size) { 3435 DMERR("%s: pool target (%llu blocks) too small: expected %llu", 3436 dm_device_name(pool->pool_md), 3437 (unsigned long long)data_size, sb_data_size); 3438 return -EINVAL; 3439 3440 } else if (data_size > sb_data_size) { 3441 if (dm_pool_metadata_needs_check(pool->pmd)) { 3442 DMERR("%s: unable to grow the data device until repaired.", 3443 dm_device_name(pool->pool_md)); 3444 return 0; 3445 } 3446 3447 if (sb_data_size) 3448 DMINFO("%s: growing the data device from %llu to %llu blocks", 3449 dm_device_name(pool->pool_md), 3450 sb_data_size, (unsigned long long)data_size); 3451 r = dm_pool_resize_data_dev(pool->pmd, data_size); 3452 if (r) { 3453 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r); 3454 return r; 3455 } 3456 3457 *need_commit = true; 3458 } 3459 3460 return 0; 3461 } 3462 3463 static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit) 3464 { 3465 int r; 3466 struct pool_c *pt = ti->private; 3467 struct pool *pool = pt->pool; 3468 dm_block_t metadata_dev_size, sb_metadata_dev_size; 3469 3470 *need_commit = false; 3471 3472 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev); 3473 3474 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size); 3475 if (r) { 3476 DMERR("%s: failed to retrieve metadata device size", 3477 dm_device_name(pool->pool_md)); 3478 return r; 3479 } 3480 3481 if (metadata_dev_size < sb_metadata_dev_size) { 3482 DMERR("%s: metadata device (%llu blocks) too small: expected %llu", 3483 dm_device_name(pool->pool_md), 3484 metadata_dev_size, sb_metadata_dev_size); 3485 return -EINVAL; 3486 3487 } else if (metadata_dev_size > sb_metadata_dev_size) { 3488 if (dm_pool_metadata_needs_check(pool->pmd)) { 3489 DMERR("%s: unable to grow the metadata device until repaired.", 3490 dm_device_name(pool->pool_md)); 3491 return 0; 3492 } 3493 3494 warn_if_metadata_device_too_big(pool->md_dev); 3495 DMINFO("%s: growing the metadata device from %llu to %llu blocks", 3496 dm_device_name(pool->pool_md), 3497 sb_metadata_dev_size, metadata_dev_size); 3498 3499 if (get_pool_mode(pool) == PM_OUT_OF_METADATA_SPACE) 3500 set_pool_mode(pool, PM_WRITE); 3501 3502 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size); 3503 if (r) { 3504 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r); 3505 return r; 3506 } 3507 3508 *need_commit = true; 3509 } 3510 3511 return 0; 3512 } 3513 3514 /* 3515 * Retrieves the number of blocks of the data device from 3516 * the superblock and compares it to the actual device size, 3517 * thus resizing the data device in case it has grown. 3518 * 3519 * This both copes with opening preallocated data devices in the ctr 3520 * being followed by a resume 3521 * -and- 3522 * calling the resume method individually after userspace has 3523 * grown the data device in reaction to a table event. 3524 */ 3525 static int pool_preresume(struct dm_target *ti) 3526 { 3527 int r; 3528 bool need_commit1, need_commit2; 3529 struct pool_c *pt = ti->private; 3530 struct pool *pool = pt->pool; 3531 3532 /* 3533 * Take control of the pool object. 3534 */ 3535 r = bind_control_target(pool, ti); 3536 if (r) 3537 return r; 3538 3539 r = maybe_resize_data_dev(ti, &need_commit1); 3540 if (r) 3541 return r; 3542 3543 r = maybe_resize_metadata_dev(ti, &need_commit2); 3544 if (r) 3545 return r; 3546 3547 if (need_commit1 || need_commit2) 3548 (void) commit(pool); 3549 3550 return 0; 3551 } 3552 3553 static void pool_suspend_active_thins(struct pool *pool) 3554 { 3555 struct thin_c *tc; 3556 3557 /* Suspend all active thin devices */ 3558 tc = get_first_thin(pool); 3559 while (tc) { 3560 dm_internal_suspend_noflush(tc->thin_md); 3561 tc = get_next_thin(pool, tc); 3562 } 3563 } 3564 3565 static void pool_resume_active_thins(struct pool *pool) 3566 { 3567 struct thin_c *tc; 3568 3569 /* Resume all active thin devices */ 3570 tc = get_first_thin(pool); 3571 while (tc) { 3572 dm_internal_resume(tc->thin_md); 3573 tc = get_next_thin(pool, tc); 3574 } 3575 } 3576 3577 static void pool_resume(struct dm_target *ti) 3578 { 3579 struct pool_c *pt = ti->private; 3580 struct pool *pool = pt->pool; 3581 3582 /* 3583 * Must requeue active_thins' bios and then resume 3584 * active_thins _before_ clearing 'suspend' flag. 3585 */ 3586 requeue_bios(pool); 3587 pool_resume_active_thins(pool); 3588 3589 spin_lock_irq(&pool->lock); 3590 pool->low_water_triggered = false; 3591 pool->suspended = false; 3592 spin_unlock_irq(&pool->lock); 3593 3594 do_waker(&pool->waker.work); 3595 } 3596 3597 static void pool_presuspend(struct dm_target *ti) 3598 { 3599 struct pool_c *pt = ti->private; 3600 struct pool *pool = pt->pool; 3601 3602 spin_lock_irq(&pool->lock); 3603 pool->suspended = true; 3604 spin_unlock_irq(&pool->lock); 3605 3606 pool_suspend_active_thins(pool); 3607 } 3608 3609 static void pool_presuspend_undo(struct dm_target *ti) 3610 { 3611 struct pool_c *pt = ti->private; 3612 struct pool *pool = pt->pool; 3613 3614 pool_resume_active_thins(pool); 3615 3616 spin_lock_irq(&pool->lock); 3617 pool->suspended = false; 3618 spin_unlock_irq(&pool->lock); 3619 } 3620 3621 static void pool_postsuspend(struct dm_target *ti) 3622 { 3623 struct pool_c *pt = ti->private; 3624 struct pool *pool = pt->pool; 3625 3626 cancel_delayed_work_sync(&pool->waker); 3627 cancel_delayed_work_sync(&pool->no_space_timeout); 3628 flush_workqueue(pool->wq); 3629 (void) commit(pool); 3630 } 3631 3632 static int check_arg_count(unsigned argc, unsigned args_required) 3633 { 3634 if (argc != args_required) { 3635 DMWARN("Message received with %u arguments instead of %u.", 3636 argc, args_required); 3637 return -EINVAL; 3638 } 3639 3640 return 0; 3641 } 3642 3643 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning) 3644 { 3645 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) && 3646 *dev_id <= MAX_DEV_ID) 3647 return 0; 3648 3649 if (warning) 3650 DMWARN("Message received with invalid device id: %s", arg); 3651 3652 return -EINVAL; 3653 } 3654 3655 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool) 3656 { 3657 dm_thin_id dev_id; 3658 int r; 3659 3660 r = check_arg_count(argc, 2); 3661 if (r) 3662 return r; 3663 3664 r = read_dev_id(argv[1], &dev_id, 1); 3665 if (r) 3666 return r; 3667 3668 r = dm_pool_create_thin(pool->pmd, dev_id); 3669 if (r) { 3670 DMWARN("Creation of new thinly-provisioned device with id %s failed.", 3671 argv[1]); 3672 return r; 3673 } 3674 3675 return 0; 3676 } 3677 3678 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool) 3679 { 3680 dm_thin_id dev_id; 3681 dm_thin_id origin_dev_id; 3682 int r; 3683 3684 r = check_arg_count(argc, 3); 3685 if (r) 3686 return r; 3687 3688 r = read_dev_id(argv[1], &dev_id, 1); 3689 if (r) 3690 return r; 3691 3692 r = read_dev_id(argv[2], &origin_dev_id, 1); 3693 if (r) 3694 return r; 3695 3696 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id); 3697 if (r) { 3698 DMWARN("Creation of new snapshot %s of device %s failed.", 3699 argv[1], argv[2]); 3700 return r; 3701 } 3702 3703 return 0; 3704 } 3705 3706 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool) 3707 { 3708 dm_thin_id dev_id; 3709 int r; 3710 3711 r = check_arg_count(argc, 2); 3712 if (r) 3713 return r; 3714 3715 r = read_dev_id(argv[1], &dev_id, 1); 3716 if (r) 3717 return r; 3718 3719 r = dm_pool_delete_thin_device(pool->pmd, dev_id); 3720 if (r) 3721 DMWARN("Deletion of thin device %s failed.", argv[1]); 3722 3723 return r; 3724 } 3725 3726 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool) 3727 { 3728 dm_thin_id old_id, new_id; 3729 int r; 3730 3731 r = check_arg_count(argc, 3); 3732 if (r) 3733 return r; 3734 3735 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) { 3736 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]); 3737 return -EINVAL; 3738 } 3739 3740 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) { 3741 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]); 3742 return -EINVAL; 3743 } 3744 3745 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id); 3746 if (r) { 3747 DMWARN("Failed to change transaction id from %s to %s.", 3748 argv[1], argv[2]); 3749 return r; 3750 } 3751 3752 return 0; 3753 } 3754 3755 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool) 3756 { 3757 int r; 3758 3759 r = check_arg_count(argc, 1); 3760 if (r) 3761 return r; 3762 3763 (void) commit(pool); 3764 3765 r = dm_pool_reserve_metadata_snap(pool->pmd); 3766 if (r) 3767 DMWARN("reserve_metadata_snap message failed."); 3768 3769 return r; 3770 } 3771 3772 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool) 3773 { 3774 int r; 3775 3776 r = check_arg_count(argc, 1); 3777 if (r) 3778 return r; 3779 3780 r = dm_pool_release_metadata_snap(pool->pmd); 3781 if (r) 3782 DMWARN("release_metadata_snap message failed."); 3783 3784 return r; 3785 } 3786 3787 /* 3788 * Messages supported: 3789 * create_thin <dev_id> 3790 * create_snap <dev_id> <origin_id> 3791 * delete <dev_id> 3792 * set_transaction_id <current_trans_id> <new_trans_id> 3793 * reserve_metadata_snap 3794 * release_metadata_snap 3795 */ 3796 static int pool_message(struct dm_target *ti, unsigned argc, char **argv, 3797 char *result, unsigned maxlen) 3798 { 3799 int r = -EINVAL; 3800 struct pool_c *pt = ti->private; 3801 struct pool *pool = pt->pool; 3802 3803 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE) { 3804 DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode", 3805 dm_device_name(pool->pool_md)); 3806 return -EOPNOTSUPP; 3807 } 3808 3809 if (!strcasecmp(argv[0], "create_thin")) 3810 r = process_create_thin_mesg(argc, argv, pool); 3811 3812 else if (!strcasecmp(argv[0], "create_snap")) 3813 r = process_create_snap_mesg(argc, argv, pool); 3814 3815 else if (!strcasecmp(argv[0], "delete")) 3816 r = process_delete_mesg(argc, argv, pool); 3817 3818 else if (!strcasecmp(argv[0], "set_transaction_id")) 3819 r = process_set_transaction_id_mesg(argc, argv, pool); 3820 3821 else if (!strcasecmp(argv[0], "reserve_metadata_snap")) 3822 r = process_reserve_metadata_snap_mesg(argc, argv, pool); 3823 3824 else if (!strcasecmp(argv[0], "release_metadata_snap")) 3825 r = process_release_metadata_snap_mesg(argc, argv, pool); 3826 3827 else 3828 DMWARN("Unrecognised thin pool target message received: %s", argv[0]); 3829 3830 if (!r) 3831 (void) commit(pool); 3832 3833 return r; 3834 } 3835 3836 static void emit_flags(struct pool_features *pf, char *result, 3837 unsigned sz, unsigned maxlen) 3838 { 3839 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled + 3840 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) + 3841 pf->error_if_no_space; 3842 DMEMIT("%u ", count); 3843 3844 if (!pf->zero_new_blocks) 3845 DMEMIT("skip_block_zeroing "); 3846 3847 if (!pf->discard_enabled) 3848 DMEMIT("ignore_discard "); 3849 3850 if (!pf->discard_passdown) 3851 DMEMIT("no_discard_passdown "); 3852 3853 if (pf->mode == PM_READ_ONLY) 3854 DMEMIT("read_only "); 3855 3856 if (pf->error_if_no_space) 3857 DMEMIT("error_if_no_space "); 3858 } 3859 3860 /* 3861 * Status line is: 3862 * <transaction id> <used metadata sectors>/<total metadata sectors> 3863 * <used data sectors>/<total data sectors> <held metadata root> 3864 * <pool mode> <discard config> <no space config> <needs_check> 3865 */ 3866 static void pool_status(struct dm_target *ti, status_type_t type, 3867 unsigned status_flags, char *result, unsigned maxlen) 3868 { 3869 int r; 3870 unsigned sz = 0; 3871 uint64_t transaction_id; 3872 dm_block_t nr_free_blocks_data; 3873 dm_block_t nr_free_blocks_metadata; 3874 dm_block_t nr_blocks_data; 3875 dm_block_t nr_blocks_metadata; 3876 dm_block_t held_root; 3877 enum pool_mode mode; 3878 char buf[BDEVNAME_SIZE]; 3879 char buf2[BDEVNAME_SIZE]; 3880 struct pool_c *pt = ti->private; 3881 struct pool *pool = pt->pool; 3882 3883 switch (type) { 3884 case STATUSTYPE_INFO: 3885 if (get_pool_mode(pool) == PM_FAIL) { 3886 DMEMIT("Fail"); 3887 break; 3888 } 3889 3890 /* Commit to ensure statistics aren't out-of-date */ 3891 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) 3892 (void) commit(pool); 3893 3894 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id); 3895 if (r) { 3896 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d", 3897 dm_device_name(pool->pool_md), r); 3898 goto err; 3899 } 3900 3901 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata); 3902 if (r) { 3903 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d", 3904 dm_device_name(pool->pool_md), r); 3905 goto err; 3906 } 3907 3908 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata); 3909 if (r) { 3910 DMERR("%s: dm_pool_get_metadata_dev_size returned %d", 3911 dm_device_name(pool->pool_md), r); 3912 goto err; 3913 } 3914 3915 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data); 3916 if (r) { 3917 DMERR("%s: dm_pool_get_free_block_count returned %d", 3918 dm_device_name(pool->pool_md), r); 3919 goto err; 3920 } 3921 3922 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data); 3923 if (r) { 3924 DMERR("%s: dm_pool_get_data_dev_size returned %d", 3925 dm_device_name(pool->pool_md), r); 3926 goto err; 3927 } 3928 3929 r = dm_pool_get_metadata_snap(pool->pmd, &held_root); 3930 if (r) { 3931 DMERR("%s: dm_pool_get_metadata_snap returned %d", 3932 dm_device_name(pool->pool_md), r); 3933 goto err; 3934 } 3935 3936 DMEMIT("%llu %llu/%llu %llu/%llu ", 3937 (unsigned long long)transaction_id, 3938 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), 3939 (unsigned long long)nr_blocks_metadata, 3940 (unsigned long long)(nr_blocks_data - nr_free_blocks_data), 3941 (unsigned long long)nr_blocks_data); 3942 3943 if (held_root) 3944 DMEMIT("%llu ", held_root); 3945 else 3946 DMEMIT("- "); 3947 3948 mode = get_pool_mode(pool); 3949 if (mode == PM_OUT_OF_DATA_SPACE) 3950 DMEMIT("out_of_data_space "); 3951 else if (is_read_only_pool_mode(mode)) 3952 DMEMIT("ro "); 3953 else 3954 DMEMIT("rw "); 3955 3956 if (!pool->pf.discard_enabled) 3957 DMEMIT("ignore_discard "); 3958 else if (pool->pf.discard_passdown) 3959 DMEMIT("discard_passdown "); 3960 else 3961 DMEMIT("no_discard_passdown "); 3962 3963 if (pool->pf.error_if_no_space) 3964 DMEMIT("error_if_no_space "); 3965 else 3966 DMEMIT("queue_if_no_space "); 3967 3968 if (dm_pool_metadata_needs_check(pool->pmd)) 3969 DMEMIT("needs_check "); 3970 else 3971 DMEMIT("- "); 3972 3973 DMEMIT("%llu ", (unsigned long long)calc_metadata_threshold(pt)); 3974 3975 break; 3976 3977 case STATUSTYPE_TABLE: 3978 DMEMIT("%s %s %lu %llu ", 3979 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev), 3980 format_dev_t(buf2, pt->data_dev->bdev->bd_dev), 3981 (unsigned long)pool->sectors_per_block, 3982 (unsigned long long)pt->low_water_blocks); 3983 emit_flags(&pt->requested_pf, result, sz, maxlen); 3984 break; 3985 } 3986 return; 3987 3988 err: 3989 DMEMIT("Error"); 3990 } 3991 3992 static int pool_iterate_devices(struct dm_target *ti, 3993 iterate_devices_callout_fn fn, void *data) 3994 { 3995 struct pool_c *pt = ti->private; 3996 3997 return fn(ti, pt->data_dev, 0, ti->len, data); 3998 } 3999 4000 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) 4001 { 4002 struct pool_c *pt = ti->private; 4003 struct pool *pool = pt->pool; 4004 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; 4005 4006 /* 4007 * If max_sectors is smaller than pool->sectors_per_block adjust it 4008 * to the highest possible power-of-2 factor of pool->sectors_per_block. 4009 * This is especially beneficial when the pool's data device is a RAID 4010 * device that has a full stripe width that matches pool->sectors_per_block 4011 * -- because even though partial RAID stripe-sized IOs will be issued to a 4012 * single RAID stripe; when aggregated they will end on a full RAID stripe 4013 * boundary.. which avoids additional partial RAID stripe writes cascading 4014 */ 4015 if (limits->max_sectors < pool->sectors_per_block) { 4016 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) { 4017 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0) 4018 limits->max_sectors--; 4019 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors); 4020 } 4021 } 4022 4023 /* 4024 * If the system-determined stacked limits are compatible with the 4025 * pool's blocksize (io_opt is a factor) do not override them. 4026 */ 4027 if (io_opt_sectors < pool->sectors_per_block || 4028 !is_factor(io_opt_sectors, pool->sectors_per_block)) { 4029 if (is_factor(pool->sectors_per_block, limits->max_sectors)) 4030 blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT); 4031 else 4032 blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT); 4033 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); 4034 } 4035 4036 /* 4037 * pt->adjusted_pf is a staging area for the actual features to use. 4038 * They get transferred to the live pool in bind_control_target() 4039 * called from pool_preresume(). 4040 */ 4041 if (!pt->adjusted_pf.discard_enabled) { 4042 /* 4043 * Must explicitly disallow stacking discard limits otherwise the 4044 * block layer will stack them if pool's data device has support. 4045 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the 4046 * user to see that, so make sure to set all discard limits to 0. 4047 */ 4048 limits->discard_granularity = 0; 4049 return; 4050 } 4051 4052 disable_passdown_if_not_supported(pt); 4053 4054 /* 4055 * The pool uses the same discard limits as the underlying data 4056 * device. DM core has already set this up. 4057 */ 4058 } 4059 4060 static struct target_type pool_target = { 4061 .name = "thin-pool", 4062 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | 4063 DM_TARGET_IMMUTABLE, 4064 .version = {1, 21, 0}, 4065 .module = THIS_MODULE, 4066 .ctr = pool_ctr, 4067 .dtr = pool_dtr, 4068 .map = pool_map, 4069 .presuspend = pool_presuspend, 4070 .presuspend_undo = pool_presuspend_undo, 4071 .postsuspend = pool_postsuspend, 4072 .preresume = pool_preresume, 4073 .resume = pool_resume, 4074 .message = pool_message, 4075 .status = pool_status, 4076 .iterate_devices = pool_iterate_devices, 4077 .io_hints = pool_io_hints, 4078 }; 4079 4080 /*---------------------------------------------------------------- 4081 * Thin target methods 4082 *--------------------------------------------------------------*/ 4083 static void thin_get(struct thin_c *tc) 4084 { 4085 refcount_inc(&tc->refcount); 4086 } 4087 4088 static void thin_put(struct thin_c *tc) 4089 { 4090 if (refcount_dec_and_test(&tc->refcount)) 4091 complete(&tc->can_destroy); 4092 } 4093 4094 static void thin_dtr(struct dm_target *ti) 4095 { 4096 struct thin_c *tc = ti->private; 4097 4098 spin_lock_irq(&tc->pool->lock); 4099 list_del_rcu(&tc->list); 4100 spin_unlock_irq(&tc->pool->lock); 4101 synchronize_rcu(); 4102 4103 thin_put(tc); 4104 wait_for_completion(&tc->can_destroy); 4105 4106 mutex_lock(&dm_thin_pool_table.mutex); 4107 4108 __pool_dec(tc->pool); 4109 dm_pool_close_thin_device(tc->td); 4110 dm_put_device(ti, tc->pool_dev); 4111 if (tc->origin_dev) 4112 dm_put_device(ti, tc->origin_dev); 4113 kfree(tc); 4114 4115 mutex_unlock(&dm_thin_pool_table.mutex); 4116 } 4117 4118 /* 4119 * Thin target parameters: 4120 * 4121 * <pool_dev> <dev_id> [origin_dev] 4122 * 4123 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool) 4124 * dev_id: the internal device identifier 4125 * origin_dev: a device external to the pool that should act as the origin 4126 * 4127 * If the pool device has discards disabled, they get disabled for the thin 4128 * device as well. 4129 */ 4130 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv) 4131 { 4132 int r; 4133 struct thin_c *tc; 4134 struct dm_dev *pool_dev, *origin_dev; 4135 struct mapped_device *pool_md; 4136 4137 mutex_lock(&dm_thin_pool_table.mutex); 4138 4139 if (argc != 2 && argc != 3) { 4140 ti->error = "Invalid argument count"; 4141 r = -EINVAL; 4142 goto out_unlock; 4143 } 4144 4145 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL); 4146 if (!tc) { 4147 ti->error = "Out of memory"; 4148 r = -ENOMEM; 4149 goto out_unlock; 4150 } 4151 tc->thin_md = dm_table_get_md(ti->table); 4152 spin_lock_init(&tc->lock); 4153 INIT_LIST_HEAD(&tc->deferred_cells); 4154 bio_list_init(&tc->deferred_bio_list); 4155 bio_list_init(&tc->retry_on_resume_list); 4156 tc->sort_bio_list = RB_ROOT; 4157 4158 if (argc == 3) { 4159 if (!strcmp(argv[0], argv[2])) { 4160 ti->error = "Error setting origin device"; 4161 r = -EINVAL; 4162 goto bad_origin_dev; 4163 } 4164 4165 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev); 4166 if (r) { 4167 ti->error = "Error opening origin device"; 4168 goto bad_origin_dev; 4169 } 4170 tc->origin_dev = origin_dev; 4171 } 4172 4173 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev); 4174 if (r) { 4175 ti->error = "Error opening pool device"; 4176 goto bad_pool_dev; 4177 } 4178 tc->pool_dev = pool_dev; 4179 4180 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) { 4181 ti->error = "Invalid device id"; 4182 r = -EINVAL; 4183 goto bad_common; 4184 } 4185 4186 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev); 4187 if (!pool_md) { 4188 ti->error = "Couldn't get pool mapped device"; 4189 r = -EINVAL; 4190 goto bad_common; 4191 } 4192 4193 tc->pool = __pool_table_lookup(pool_md); 4194 if (!tc->pool) { 4195 ti->error = "Couldn't find pool object"; 4196 r = -EINVAL; 4197 goto bad_pool_lookup; 4198 } 4199 __pool_inc(tc->pool); 4200 4201 if (get_pool_mode(tc->pool) == PM_FAIL) { 4202 ti->error = "Couldn't open thin device, Pool is in fail mode"; 4203 r = -EINVAL; 4204 goto bad_pool; 4205 } 4206 4207 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td); 4208 if (r) { 4209 ti->error = "Couldn't open thin internal device"; 4210 goto bad_pool; 4211 } 4212 4213 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block); 4214 if (r) 4215 goto bad; 4216 4217 ti->num_flush_bios = 1; 4218 ti->flush_supported = true; 4219 ti->per_io_data_size = sizeof(struct dm_thin_endio_hook); 4220 4221 /* In case the pool supports discards, pass them on. */ 4222 if (tc->pool->pf.discard_enabled) { 4223 ti->discards_supported = true; 4224 ti->num_discard_bios = 1; 4225 } 4226 4227 mutex_unlock(&dm_thin_pool_table.mutex); 4228 4229 spin_lock_irq(&tc->pool->lock); 4230 if (tc->pool->suspended) { 4231 spin_unlock_irq(&tc->pool->lock); 4232 mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */ 4233 ti->error = "Unable to activate thin device while pool is suspended"; 4234 r = -EINVAL; 4235 goto bad; 4236 } 4237 refcount_set(&tc->refcount, 1); 4238 init_completion(&tc->can_destroy); 4239 list_add_tail_rcu(&tc->list, &tc->pool->active_thins); 4240 spin_unlock_irq(&tc->pool->lock); 4241 /* 4242 * This synchronize_rcu() call is needed here otherwise we risk a 4243 * wake_worker() call finding no bios to process (because the newly 4244 * added tc isn't yet visible). So this reduces latency since we 4245 * aren't then dependent on the periodic commit to wake_worker(). 4246 */ 4247 synchronize_rcu(); 4248 4249 dm_put(pool_md); 4250 4251 return 0; 4252 4253 bad: 4254 dm_pool_close_thin_device(tc->td); 4255 bad_pool: 4256 __pool_dec(tc->pool); 4257 bad_pool_lookup: 4258 dm_put(pool_md); 4259 bad_common: 4260 dm_put_device(ti, tc->pool_dev); 4261 bad_pool_dev: 4262 if (tc->origin_dev) 4263 dm_put_device(ti, tc->origin_dev); 4264 bad_origin_dev: 4265 kfree(tc); 4266 out_unlock: 4267 mutex_unlock(&dm_thin_pool_table.mutex); 4268 4269 return r; 4270 } 4271 4272 static int thin_map(struct dm_target *ti, struct bio *bio) 4273 { 4274 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector); 4275 4276 return thin_bio_map(ti, bio); 4277 } 4278 4279 static int thin_endio(struct dm_target *ti, struct bio *bio, 4280 blk_status_t *err) 4281 { 4282 unsigned long flags; 4283 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); 4284 struct list_head work; 4285 struct dm_thin_new_mapping *m, *tmp; 4286 struct pool *pool = h->tc->pool; 4287 4288 if (h->shared_read_entry) { 4289 INIT_LIST_HEAD(&work); 4290 dm_deferred_entry_dec(h->shared_read_entry, &work); 4291 4292 spin_lock_irqsave(&pool->lock, flags); 4293 list_for_each_entry_safe(m, tmp, &work, list) { 4294 list_del(&m->list); 4295 __complete_mapping_preparation(m); 4296 } 4297 spin_unlock_irqrestore(&pool->lock, flags); 4298 } 4299 4300 if (h->all_io_entry) { 4301 INIT_LIST_HEAD(&work); 4302 dm_deferred_entry_dec(h->all_io_entry, &work); 4303 if (!list_empty(&work)) { 4304 spin_lock_irqsave(&pool->lock, flags); 4305 list_for_each_entry_safe(m, tmp, &work, list) 4306 list_add_tail(&m->list, &pool->prepared_discards); 4307 spin_unlock_irqrestore(&pool->lock, flags); 4308 wake_worker(pool); 4309 } 4310 } 4311 4312 if (h->cell) 4313 cell_defer_no_holder(h->tc, h->cell); 4314 4315 return DM_ENDIO_DONE; 4316 } 4317 4318 static void thin_presuspend(struct dm_target *ti) 4319 { 4320 struct thin_c *tc = ti->private; 4321 4322 if (dm_noflush_suspending(ti)) 4323 noflush_work(tc, do_noflush_start); 4324 } 4325 4326 static void thin_postsuspend(struct dm_target *ti) 4327 { 4328 struct thin_c *tc = ti->private; 4329 4330 /* 4331 * The dm_noflush_suspending flag has been cleared by now, so 4332 * unfortunately we must always run this. 4333 */ 4334 noflush_work(tc, do_noflush_stop); 4335 } 4336 4337 static int thin_preresume(struct dm_target *ti) 4338 { 4339 struct thin_c *tc = ti->private; 4340 4341 if (tc->origin_dev) 4342 tc->origin_size = get_dev_size(tc->origin_dev->bdev); 4343 4344 return 0; 4345 } 4346 4347 /* 4348 * <nr mapped sectors> <highest mapped sector> 4349 */ 4350 static void thin_status(struct dm_target *ti, status_type_t type, 4351 unsigned status_flags, char *result, unsigned maxlen) 4352 { 4353 int r; 4354 ssize_t sz = 0; 4355 dm_block_t mapped, highest; 4356 char buf[BDEVNAME_SIZE]; 4357 struct thin_c *tc = ti->private; 4358 4359 if (get_pool_mode(tc->pool) == PM_FAIL) { 4360 DMEMIT("Fail"); 4361 return; 4362 } 4363 4364 if (!tc->td) 4365 DMEMIT("-"); 4366 else { 4367 switch (type) { 4368 case STATUSTYPE_INFO: 4369 r = dm_thin_get_mapped_count(tc->td, &mapped); 4370 if (r) { 4371 DMERR("dm_thin_get_mapped_count returned %d", r); 4372 goto err; 4373 } 4374 4375 r = dm_thin_get_highest_mapped_block(tc->td, &highest); 4376 if (r < 0) { 4377 DMERR("dm_thin_get_highest_mapped_block returned %d", r); 4378 goto err; 4379 } 4380 4381 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block); 4382 if (r) 4383 DMEMIT("%llu", ((highest + 1) * 4384 tc->pool->sectors_per_block) - 1); 4385 else 4386 DMEMIT("-"); 4387 break; 4388 4389 case STATUSTYPE_TABLE: 4390 DMEMIT("%s %lu", 4391 format_dev_t(buf, tc->pool_dev->bdev->bd_dev), 4392 (unsigned long) tc->dev_id); 4393 if (tc->origin_dev) 4394 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev)); 4395 break; 4396 } 4397 } 4398 4399 return; 4400 4401 err: 4402 DMEMIT("Error"); 4403 } 4404 4405 static int thin_iterate_devices(struct dm_target *ti, 4406 iterate_devices_callout_fn fn, void *data) 4407 { 4408 sector_t blocks; 4409 struct thin_c *tc = ti->private; 4410 struct pool *pool = tc->pool; 4411 4412 /* 4413 * We can't call dm_pool_get_data_dev_size() since that blocks. So 4414 * we follow a more convoluted path through to the pool's target. 4415 */ 4416 if (!pool->ti) 4417 return 0; /* nothing is bound */ 4418 4419 blocks = pool->ti->len; 4420 (void) sector_div(blocks, pool->sectors_per_block); 4421 if (blocks) 4422 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data); 4423 4424 return 0; 4425 } 4426 4427 static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) 4428 { 4429 struct thin_c *tc = ti->private; 4430 struct pool *pool = tc->pool; 4431 4432 if (!pool->pf.discard_enabled) 4433 return; 4434 4435 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; 4436 limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */ 4437 } 4438 4439 static struct target_type thin_target = { 4440 .name = "thin", 4441 .version = {1, 21, 0}, 4442 .module = THIS_MODULE, 4443 .ctr = thin_ctr, 4444 .dtr = thin_dtr, 4445 .map = thin_map, 4446 .end_io = thin_endio, 4447 .preresume = thin_preresume, 4448 .presuspend = thin_presuspend, 4449 .postsuspend = thin_postsuspend, 4450 .status = thin_status, 4451 .iterate_devices = thin_iterate_devices, 4452 .io_hints = thin_io_hints, 4453 }; 4454 4455 /*----------------------------------------------------------------*/ 4456 4457 static int __init dm_thin_init(void) 4458 { 4459 int r = -ENOMEM; 4460 4461 pool_table_init(); 4462 4463 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0); 4464 if (!_new_mapping_cache) 4465 return r; 4466 4467 r = dm_register_target(&thin_target); 4468 if (r) 4469 goto bad_new_mapping_cache; 4470 4471 r = dm_register_target(&pool_target); 4472 if (r) 4473 goto bad_thin_target; 4474 4475 return 0; 4476 4477 bad_thin_target: 4478 dm_unregister_target(&thin_target); 4479 bad_new_mapping_cache: 4480 kmem_cache_destroy(_new_mapping_cache); 4481 4482 return r; 4483 } 4484 4485 static void dm_thin_exit(void) 4486 { 4487 dm_unregister_target(&thin_target); 4488 dm_unregister_target(&pool_target); 4489 4490 kmem_cache_destroy(_new_mapping_cache); 4491 4492 pool_table_exit(); 4493 } 4494 4495 module_init(dm_thin_init); 4496 module_exit(dm_thin_exit); 4497 4498 module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR); 4499 MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds"); 4500 4501 MODULE_DESCRIPTION(DM_NAME " thin provisioning target"); 4502 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); 4503 MODULE_LICENSE("GPL"); 4504