drivers/md/dm-thin.c

   1 /*
   2  * Copyright (C) 2011-2012 Red Hat UK.
   3  *
   4  * This file is released under the GPL.
   5  */
   6
   7 #include "dm-thin-metadata.h"
   8 #include "dm-bio-prison.h"
   9 #include "dm.h"
  10
  11 #include <linux/device-mapper.h>
  12 #include <linux/dm-io.h>
  13 #include <linux/dm-kcopyd.h>
  14 #include <linux/list.h>
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18
  19 #define DM_MSG_PREFIX   "thin"
  20
  21 /*
  22  * Tunable constants
  23  */
  24 #define ENDIO_HOOK_POOL_SIZE 1024
  25 #define MAPPING_POOL_SIZE 1024
  26 #define PRISON_CELLS 1024
  27 #define COMMIT_PERIOD HZ
  28
  29 /*
  30  * The block size of the device holding pool data must be
  31  * between 64KB and 1GB.
  32  */
  33 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
  34 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
  35
  36 /*
  37  * Device id is restricted to 24 bits.
  38  */
  39 #define MAX_DEV_ID ((1 << 24) - 1)
  40
  41 /*
  42  * How do we handle breaking sharing of data blocks?
  43  * =================================================
  44  *
  45  * We use a standard copy-on-write btree to store the mappings for the
  46  * devices (note I'm talking about copy-on-write of the metadata here, not
  47  * the data).  When you take an internal snapshot you clone the root node
  48  * of the origin btree.  After this there is no concept of an origin or a
  49  * snapshot.  They are just two device trees that happen to point to the
  50  * same data blocks.
  51  *
  52  * When we get a write in we decide if it's to a shared data block using
  53  * some timestamp magic.  If it is, we have to break sharing.
  54  *
  55  * Let's say we write to a shared block in what was the origin.  The
  56  * steps are:
  57  *
  58  * i) plug io further to this physical block. (see bio_prison code).
  59  *
  60  * ii) quiesce any read io to that shared data block.  Obviously
  61  * including all devices that share this block.  (see dm_deferred_set code)
  62  *
  63  * iii) copy the data block to a newly allocate block.  This step can be
  64  * missed out if the io covers the block. (schedule_copy).
  65  *
  66  * iv) insert the new mapping into the origin's btree
  67  * (process_prepared_mapping).  This act of inserting breaks some
  68  * sharing of btree nodes between the two devices.  Breaking sharing only
  69  * effects the btree of that specific device.  Btrees for the other
  70  * devices that share the block never change.  The btree for the origin
  71  * device as it was after the last commit is untouched, ie. we're using
  72  * persistent data structures in the functional programming sense.
  73  *
  74  * v) unplug io to this physical block, including the io that triggered
  75  * the breaking of sharing.
  76  *
  77  * Steps (ii) and (iii) occur in parallel.
  78  *
  79  * The metadata _doesn't_ need to be committed before the io continues.  We
  80  * get away with this because the io is always written to a _new_ block.
  81  * If there's a crash, then:
  82  *
  83  * - The origin mapping will point to the old origin block (the shared
  84  * one).  This will contain the data as it was before the io that triggered
  85  * the breaking of sharing came in.
  86  *
  87  * - The snap mapping still points to the old block.  As it would after
  88  * the commit.
  89  *
  90  * The downside of this scheme is the timestamp magic isn't perfect, and
  91  * will continue to think that data block in the snapshot device is shared
  92  * even after the write to the origin has broken sharing.  I suspect data
  93  * blocks will typically be shared by many different devices, so we're
  94  * breaking sharing n + 1 times, rather than n, where n is the number of
  95  * devices that reference this data block.  At the moment I think the
  96  * benefits far, far outweigh the disadvantages.
  97  */
  98
  99 /*----------------------------------------------------------------*/
 100
 101 /*
 102  * Key building.
 103  */
 104 static void build_data_key(struct dm_thin_device *td,
 105                            dm_block_t b, struct dm_cell_key *key)
 106 {
 107         key->virtual = 0;
 108         key->dev = dm_thin_dev_id(td);
 109         key->block = b;
 110 }
 111
 112 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
 113                               struct dm_cell_key *key)
 114 {
 115         key->virtual = 1;
 116         key->dev = dm_thin_dev_id(td);
 117         key->block = b;
 118 }
 119
 120 /*----------------------------------------------------------------*/
 121
 122 /*
 123  * A pool device ties together a metadata device and a data device.  It
 124  * also provides the interface for creating and destroying internal
 125  * devices.
 126  */
 127 struct dm_thin_new_mapping;
 128
 129 /*
 130  * The pool runs in 3 modes.  Ordered in degraded order for comparisons.
 131  */
 132 enum pool_mode {
 133         PM_WRITE,               /* metadata may be changed */
 134         PM_READ_ONLY,           /* metadata may not be changed */
 135         PM_FAIL,                /* all I/O fails */
 136 };
 137
 138 struct pool_features {
 139         enum pool_mode mode;
 140
 141         bool zero_new_blocks:1;
 142         bool discard_enabled:1;
 143         bool discard_passdown:1;
 144 };
 145
 146 struct thin_c;
 147 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
 148 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
 149
 150 struct pool {
 151         struct list_head list;
 152         struct dm_target *ti;   /* Only set if a pool target is bound */
 153
 154         struct mapped_device *pool_md;
 155         struct block_device *md_dev;
 156         struct dm_pool_metadata *pmd;
 157
 158         dm_block_t low_water_blocks;
 159         uint32_t sectors_per_block;
 160         int sectors_per_block_shift;
 161
 162         struct pool_features pf;
 163         unsigned low_water_triggered:1; /* A dm event has been sent */
 164         unsigned no_free_space:1;       /* A -ENOSPC warning has been issued */
 165
 166         struct dm_bio_prison *prison;
 167         struct dm_kcopyd_client *copier;
 168
 169         struct workqueue_struct *wq;
 170         struct work_struct worker;
 171         struct delayed_work waker;
 172
 173         unsigned long last_commit_jiffies;
 174         unsigned ref_count;
 175
 176         spinlock_t lock;
 177         struct bio_list deferred_bios;
 178         struct bio_list deferred_flush_bios;
 179         struct list_head prepared_mappings;
 180         struct list_head prepared_discards;
 181
 182         struct bio_list retry_on_resume_list;
 183
 184         struct dm_deferred_set *shared_read_ds;
 185         struct dm_deferred_set *all_io_ds;
 186
 187         struct dm_thin_new_mapping *next_mapping;
 188         mempool_t *mapping_pool;
 189         mempool_t *endio_hook_pool;
 190
 191         process_bio_fn process_bio;
 192         process_bio_fn process_discard;
 193
 194         process_mapping_fn process_prepared_mapping;
 195         process_mapping_fn process_prepared_discard;
 196 };
 197
 198 static enum pool_mode get_pool_mode(struct pool *pool);
 199 static void set_pool_mode(struct pool *pool, enum pool_mode mode);
 200
 201 /*
 202  * Target context for a pool.
 203  */
 204 struct pool_c {
 205         struct dm_target *ti;
 206         struct pool *pool;
 207         struct dm_dev *data_dev;
 208         struct dm_dev *metadata_dev;
 209         struct dm_target_callbacks callbacks;
 210
 211         dm_block_t low_water_blocks;
 212         struct pool_features requested_pf; /* Features requested during table load */
 213         struct pool_features adjusted_pf;  /* Features used after adjusting for constituent devices */
 214 };
 215
 216 /*
 217  * Target context for a thin.
 218  */
 219 struct thin_c {
 220         struct dm_dev *pool_dev;
 221         struct dm_dev *origin_dev;
 222         dm_thin_id dev_id;
 223
 224         struct pool *pool;
 225         struct dm_thin_device *td;
 226 };
 227
 228 /*----------------------------------------------------------------*/
 229
 230 /*
 231  * A global list of pools that uses a struct mapped_device as a key.
 232  */
 233 static struct dm_thin_pool_table {
 234         struct mutex mutex;
 235         struct list_head pools;
 236 } dm_thin_pool_table;
 237
 238 static void pool_table_init(void)
 239 {
 240         mutex_init(&dm_thin_pool_table.mutex);
 241         INIT_LIST_HEAD(&dm_thin_pool_table.pools);
 242 }
 243
 244 static void __pool_table_insert(struct pool *pool)
 245 {
 246         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
 247         list_add(&pool->list, &dm_thin_pool_table.pools);
 248 }
 249
 250 static void __pool_table_remove(struct pool *pool)
 251 {
 252         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
 253         list_del(&pool->list);
 254 }
 255
 256 static struct pool *__pool_table_lookup(struct mapped_device *md)
 257 {
 258         struct pool *pool = NULL, *tmp;
 259
 260         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
 261
 262         list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
 263                 if (tmp->pool_md == md) {
 264                         pool = tmp;
 265                         break;
 266                 }
 267         }
 268
 269         return pool;
 270 }
 271
 272 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
 273 {
 274         struct pool *pool = NULL, *tmp;
 275
 276         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
 277
 278         list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
 279                 if (tmp->md_dev == md_dev) {
 280                         pool = tmp;
 281                         break;
 282                 }
 283         }
 284
 285         return pool;
 286 }
 287
 288 /*----------------------------------------------------------------*/
 289
 290 struct dm_thin_endio_hook {
 291         struct thin_c *tc;
 292         struct dm_deferred_entry *shared_read_entry;
 293         struct dm_deferred_entry *all_io_entry;
 294         struct dm_thin_new_mapping *overwrite_mapping;
 295 };
 296
 297 static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
 298 {
 299         struct bio *bio;
 300         struct bio_list bios;
 301
 302         bio_list_init(&bios);
 303         bio_list_merge(&bios, master);
 304         bio_list_init(master);
 305
 306         while ((bio = bio_list_pop(&bios))) {
 307                 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
 308
 309                 if (h->tc == tc)
 310                         bio_endio(bio, DM_ENDIO_REQUEUE);
 311                 else
 312                         bio_list_add(master, bio);
 313         }
 314 }
 315
 316 static void requeue_io(struct thin_c *tc)
 317 {
 318         struct pool *pool = tc->pool;
 319         unsigned long flags;
 320
 321         spin_lock_irqsave(&pool->lock, flags);
 322         __requeue_bio_list(tc, &pool->deferred_bios);
 323         __requeue_bio_list(tc, &pool->retry_on_resume_list);
 324         spin_unlock_irqrestore(&pool->lock, flags);
 325 }
 326
 327 /*
 328  * This section of code contains the logic for processing a thin device's IO.
 329  * Much of the code depends on pool object resources (lists, workqueues, etc)
 330  * but most is exclusively called from the thin target rather than the thin-pool
 331  * target.
 332  */
 333
 334 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
 335 {
 336         sector_t block_nr = bio->bi_sector;
 337
 338         if (tc->pool->sectors_per_block_shift < 0)
 339                 (void) sector_div(block_nr, tc->pool->sectors_per_block);
 340         else
 341                 block_nr >>= tc->pool->sectors_per_block_shift;
 342
 343         return block_nr;
 344 }
 345
 346 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
 347 {
 348         struct pool *pool = tc->pool;
 349         sector_t bi_sector = bio->bi_sector;
 350
 351         bio->bi_bdev = tc->pool_dev->bdev;
 352         if (tc->pool->sectors_per_block_shift < 0)
 353                 bio->bi_sector = (block * pool->sectors_per_block) +
 354                                  sector_div(bi_sector, pool->sectors_per_block);
 355         else
 356                 bio->bi_sector = (block << pool->sectors_per_block_shift) |
 357                                 (bi_sector & (pool->sectors_per_block - 1));
 358 }
 359
 360 static void remap_to_origin(struct thin_c *tc, struct bio *bio)
 361 {
 362         bio->bi_bdev = tc->origin_dev->bdev;
 363 }
 364
 365 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
 366 {
 367         return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
 368                 dm_thin_changed_this_transaction(tc->td);
 369 }
 370
 371 static void issue(struct thin_c *tc, struct bio *bio)
 372 {
 373         struct pool *pool = tc->pool;
 374         unsigned long flags;
 375
 376         if (!bio_triggers_commit(tc, bio)) {
 377                 generic_make_request(bio);
 378                 return;
 379         }
 380
 381         /*
 382          * Complete bio with an error if earlier I/O caused changes to
 383          * the metadata that can't be committed e.g, due to I/O errors
 384          * on the metadata device.
 385          */
 386         if (dm_thin_aborted_changes(tc->td)) {
 387                 bio_io_error(bio);
 388                 return;
 389         }
 390
 391         /*
 392          * Batch together any bios that trigger commits and then issue a
 393          * single commit for them in process_deferred_bios().
 394          */
 395         spin_lock_irqsave(&pool->lock, flags);
 396         bio_list_add(&pool->deferred_flush_bios, bio);
 397         spin_unlock_irqrestore(&pool->lock, flags);
 398 }
 399
 400 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
 401 {
 402         remap_to_origin(tc, bio);
 403         issue(tc, bio);
 404 }
 405
 406 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
 407                             dm_block_t block)
 408 {
 409         remap(tc, bio, block);
 410         issue(tc, bio);
 411 }
 412
 413 /*
 414  * wake_worker() is used when new work is queued and when pool_resume is
 415  * ready to continue deferred IO processing.
 416  */
 417 static void wake_worker(struct pool *pool)
 418 {
 419         queue_work(pool->wq, &pool->worker);
 420 }
 421
 422 /*----------------------------------------------------------------*/
 423
 424 /*
 425  * Bio endio functions.
 426  */
 427 struct dm_thin_new_mapping {
 428         struct list_head list;
 429
 430         unsigned quiesced:1;
 431         unsigned prepared:1;
 432         unsigned pass_discard:1;
 433
 434         struct thin_c *tc;
 435         dm_block_t virt_block;
 436         dm_block_t data_block;
 437         struct dm_bio_prison_cell *cell, *cell2;
 438         int err;
 439
 440         /*
 441          * If the bio covers the whole area of a block then we can avoid
 442          * zeroing or copying.  Instead this bio is hooked.  The bio will
 443          * still be in the cell, so care has to be taken to avoid issuing
 444          * the bio twice.
 445          */
 446         struct bio *bio;
 447         bio_end_io_t *saved_bi_end_io;
 448 };
 449
 450 static void __maybe_add_mapping(struct dm_thin_new_mapping *m)
 451 {
 452         struct pool *pool = m->tc->pool;
 453
 454         if (m->quiesced && m->prepared) {
 455                 list_add(&m->list, &pool->prepared_mappings);
 456                 wake_worker(pool);
 457         }
 458 }
 459
 460 static void copy_complete(int read_err, unsigned long write_err, void *context)
 461 {
 462         unsigned long flags;
 463         struct dm_thin_new_mapping *m = context;
 464         struct pool *pool = m->tc->pool;
 465
 466         m->err = read_err || write_err ? -EIO : 0;
 467
 468         spin_lock_irqsave(&pool->lock, flags);
 469         m->prepared = 1;
 470         __maybe_add_mapping(m);
 471         spin_unlock_irqrestore(&pool->lock, flags);
 472 }
 473
 474 static void overwrite_endio(struct bio *bio, int err)
 475 {
 476         unsigned long flags;
 477         struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
 478         struct dm_thin_new_mapping *m = h->overwrite_mapping;
 479         struct pool *pool = m->tc->pool;
 480
 481         m->err = err;
 482
 483         spin_lock_irqsave(&pool->lock, flags);
 484         m->prepared = 1;
 485         __maybe_add_mapping(m);
 486         spin_unlock_irqrestore(&pool->lock, flags);
 487 }
 488
 489 /*----------------------------------------------------------------*/
 490
 491 /*
 492  * Workqueue.
 493  */
 494
 495 /*
 496  * Prepared mapping jobs.
 497  */
 498
 499 /*
 500  * This sends the bios in the cell back to the deferred_bios list.
 501  */
 502 static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell,
 503                        dm_block_t data_block)
 504 {
 505         struct pool *pool = tc->pool;
 506         unsigned long flags;
 507
 508         spin_lock_irqsave(&pool->lock, flags);
 509         dm_cell_release(cell, &pool->deferred_bios);
 510         spin_unlock_irqrestore(&tc->pool->lock, flags);
 511
 512         wake_worker(pool);
 513 }
 514
 515 /*
 516  * Same as cell_defer above, except it omits one particular detainee,
 517  * a write bio that covers the block and has already been processed.
 518  */
 519 static void cell_defer_except(struct thin_c *tc, struct dm_bio_prison_cell *cell)
 520 {
 521         struct bio_list bios;
 522         struct pool *pool = tc->pool;
 523         unsigned long flags;
 524
 525         bio_list_init(&bios);
 526
 527         spin_lock_irqsave(&pool->lock, flags);
 528         dm_cell_release_no_holder(cell, &pool->deferred_bios);
 529         spin_unlock_irqrestore(&pool->lock, flags);
 530
 531         wake_worker(pool);
 532 }
 533
 534 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
 535 {
 536         if (m->bio)
 537                 m->bio->bi_end_io = m->saved_bi_end_io;
 538         dm_cell_error(m->cell);
 539         list_del(&m->list);
 540         mempool_free(m, m->tc->pool->mapping_pool);
 541 }
 542 static void process_prepared_mapping(struct dm_thin_new_mapping *m)
 543 {
 544         struct thin_c *tc = m->tc;
 545         struct bio *bio;
 546         int r;
 547
 548         bio = m->bio;
 549         if (bio)
 550                 bio->bi_end_io = m->saved_bi_end_io;
 551
 552         if (m->err) {
 553                 dm_cell_error(m->cell);
 554                 goto out;
 555         }
 556
 557         /*
 558          * Commit the prepared block into the mapping btree.
 559          * Any I/O for this block arriving after this point will get
 560          * remapped to it directly.
 561          */
 562         r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
 563         if (r) {
 564                 DMERR("dm_thin_insert_block() failed");
 565                 dm_cell_error(m->cell);
 566                 goto out;
 567         }
 568
 569         /*
 570          * Release any bios held while the block was being provisioned.
 571          * If we are processing a write bio that completely covers the block,
 572          * we already processed it so can ignore it now when processing
 573          * the bios in the cell.
 574          */
 575         if (bio) {
 576                 cell_defer_except(tc, m->cell);
 577                 bio_endio(bio, 0);
 578         } else
 579                 cell_defer(tc, m->cell, m->data_block);
 580
 581 out:
 582         list_del(&m->list);
 583         mempool_free(m, tc->pool->mapping_pool);
 584 }
 585
 586 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
 587 {
 588         struct thin_c *tc = m->tc;
 589
 590         bio_io_error(m->bio);
 591         cell_defer_except(tc, m->cell);
 592         cell_defer_except(tc, m->cell2);
 593         mempool_free(m, tc->pool->mapping_pool);
 594 }
 595
 596 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
 597 {
 598         struct thin_c *tc = m->tc;
 599
 600         if (m->pass_discard)
 601                 remap_and_issue(tc, m->bio, m->data_block);
 602         else
 603                 bio_endio(m->bio, 0);
 604
 605         cell_defer_except(tc, m->cell);
 606         cell_defer_except(tc, m->cell2);
 607         mempool_free(m, tc->pool->mapping_pool);
 608 }
 609
 610 static void process_prepared_discard(struct dm_thin_new_mapping *m)
 611 {
 612         int r;
 613         struct thin_c *tc = m->tc;
 614
 615         r = dm_thin_remove_block(tc->td, m->virt_block);
 616         if (r)
 617                 DMERR("dm_thin_remove_block() failed");
 618
 619         process_prepared_discard_passdown(m);
 620 }
 621
 622 static void process_prepared(struct pool *pool, struct list_head *head,
 623                              process_mapping_fn *fn)
 624 {
 625         unsigned long flags;
 626         struct list_head maps;
 627         struct dm_thin_new_mapping *m, *tmp;
 628
 629         INIT_LIST_HEAD(&maps);
 630         spin_lock_irqsave(&pool->lock, flags);
 631         list_splice_init(head, &maps);
 632         spin_unlock_irqrestore(&pool->lock, flags);
 633
 634         list_for_each_entry_safe(m, tmp, &maps, list)
 635                 (*fn)(m);
 636 }
 637
 638 /*
 639  * Deferred bio jobs.
 640  */
 641 static int io_overlaps_block(struct pool *pool, struct bio *bio)
 642 {
 643         return bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT);
 644 }
 645
 646 static int io_overwrites_block(struct pool *pool, struct bio *bio)
 647 {
 648         return (bio_data_dir(bio) == WRITE) &&
 649                 io_overlaps_block(pool, bio);
 650 }
 651
 652 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
 653                                bio_end_io_t *fn)
 654 {
 655         *save = bio->bi_end_io;
 656         bio->bi_end_io = fn;
 657 }
 658
 659 static int ensure_next_mapping(struct pool *pool)
 660 {
 661         if (pool->next_mapping)
 662                 return 0;
 663
 664         pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
 665
 666         return pool->next_mapping ? 0 : -ENOMEM;
 667 }
 668
 669 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
 670 {
 671         struct dm_thin_new_mapping *r = pool->next_mapping;
 672
 673         BUG_ON(!pool->next_mapping);
 674
 675         pool->next_mapping = NULL;
 676
 677         return r;
 678 }
 679
 680 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
 681                           struct dm_dev *origin, dm_block_t data_origin,
 682                           dm_block_t data_dest,
 683                           struct dm_bio_prison_cell *cell, struct bio *bio)
 684 {
 685         int r;
 686         struct pool *pool = tc->pool;
 687         struct dm_thin_new_mapping *m = get_next_mapping(pool);
 688
 689         INIT_LIST_HEAD(&m->list);
 690         m->quiesced = 0;
 691         m->prepared = 0;
 692         m->tc = tc;
 693         m->virt_block = virt_block;
 694         m->data_block = data_dest;
 695         m->cell = cell;
 696         m->err = 0;
 697         m->bio = NULL;
 698
 699         if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
 700                 m->quiesced = 1;
 701
 702         /*
 703          * IO to pool_dev remaps to the pool target's data_dev.
 704          *
 705          * If the whole block of data is being overwritten, we can issue the
 706          * bio immediately. Otherwise we use kcopyd to clone the data first.
 707          */
 708         if (io_overwrites_block(pool, bio)) {
 709                 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
 710
 711                 h->overwrite_mapping = m;
 712                 m->bio = bio;
 713                 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
 714                 remap_and_issue(tc, bio, data_dest);
 715         } else {
 716                 struct dm_io_region from, to;
 717
 718                 from.bdev = origin->bdev;
 719                 from.sector = data_origin * pool->sectors_per_block;
 720                 from.count = pool->sectors_per_block;
 721
 722                 to.bdev = tc->pool_dev->bdev;
 723                 to.sector = data_dest * pool->sectors_per_block;
 724                 to.count = pool->sectors_per_block;
 725
 726                 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
 727                                    0, copy_complete, m);
 728                 if (r < 0) {
 729                         mempool_free(m, pool->mapping_pool);
 730                         DMERR("dm_kcopyd_copy() failed");
 731                         dm_cell_error(cell);
 732                 }
 733         }
 734 }
 735
 736 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
 737                                    dm_block_t data_origin, dm_block_t data_dest,
 738                                    struct dm_bio_prison_cell *cell, struct bio *bio)
 739 {
 740         schedule_copy(tc, virt_block, tc->pool_dev,
 741                       data_origin, data_dest, cell, bio);
 742 }
 743
 744 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
 745                                    dm_block_t data_dest,
 746                                    struct dm_bio_prison_cell *cell, struct bio *bio)
 747 {
 748         schedule_copy(tc, virt_block, tc->origin_dev,
 749                       virt_block, data_dest, cell, bio);
 750 }
 751
 752 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
 753                           dm_block_t data_block, struct dm_bio_prison_cell *cell,
 754                           struct bio *bio)
 755 {
 756         struct pool *pool = tc->pool;
 757         struct dm_thin_new_mapping *m = get_next_mapping(pool);
 758
 759         INIT_LIST_HEAD(&m->list);
 760         m->quiesced = 1;
 761         m->prepared = 0;
 762         m->tc = tc;
 763         m->virt_block = virt_block;
 764         m->data_block = data_block;
 765         m->cell = cell;
 766         m->err = 0;
 767         m->bio = NULL;
 768
 769         /*
 770          * If the whole block of data is being overwritten or we are not
 771          * zeroing pre-existing data, we can issue the bio immediately.
 772          * Otherwise we use kcopyd to zero the data first.
 773          */
 774         if (!pool->pf.zero_new_blocks)
 775                 process_prepared_mapping(m);
 776
 777         else if (io_overwrites_block(pool, bio)) {
 778                 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
 779
 780                 h->overwrite_mapping = m;
 781                 m->bio = bio;
 782                 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
 783                 remap_and_issue(tc, bio, data_block);
 784         } else {
 785                 int r;
 786                 struct dm_io_region to;
 787
 788                 to.bdev = tc->pool_dev->bdev;
 789                 to.sector = data_block * pool->sectors_per_block;
 790                 to.count = pool->sectors_per_block;
 791
 792                 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
 793                 if (r < 0) {
 794                         mempool_free(m, pool->mapping_pool);
 795                         DMERR("dm_kcopyd_zero() failed");
 796                         dm_cell_error(cell);
 797                 }
 798         }
 799 }
 800
 801 static int commit(struct pool *pool)
 802 {
 803         int r;
 804
 805         r = dm_pool_commit_metadata(pool->pmd);
 806         if (r)
 807                 DMERR("commit failed, error = %d", r);
 808
 809         return r;
 810 }
 811
 812 /*
 813  * A non-zero return indicates read_only or fail_io mode.
 814  * Many callers don't care about the return value.
 815  */
 816 static int commit_or_fallback(struct pool *pool)
 817 {
 818         int r;
 819
 820         if (get_pool_mode(pool) != PM_WRITE)
 821                 return -EINVAL;
 822
 823         r = commit(pool);
 824         if (r)
 825                 set_pool_mode(pool, PM_READ_ONLY);
 826
 827         return r;
 828 }
 829
 830 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
 831 {
 832         int r;
 833         dm_block_t free_blocks;
 834         unsigned long flags;
 835         struct pool *pool = tc->pool;
 836
 837         r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
 838         if (r)
 839                 return r;
 840
 841         if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
 842                 DMWARN("%s: reached low water mark, sending event.",
 843                        dm_device_name(pool->pool_md));
 844                 spin_lock_irqsave(&pool->lock, flags);
 845                 pool->low_water_triggered = 1;
 846                 spin_unlock_irqrestore(&pool->lock, flags);
 847                 dm_table_event(pool->ti->table);
 848         }
 849
 850         if (!free_blocks) {
 851                 if (pool->no_free_space)
 852                         return -ENOSPC;
 853                 else {
 854                         /*
 855                          * Try to commit to see if that will free up some
 856                          * more space.
 857                          */
 858                         (void) commit_or_fallback(pool);
 859
 860                         r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
 861                         if (r)
 862                                 return r;
 863
 864                         /*
 865                          * If we still have no space we set a flag to avoid
 866                          * doing all this checking and return -ENOSPC.
 867                          */
 868                         if (!free_blocks) {
 869                                 DMWARN("%s: no free space available.",
 870                                        dm_device_name(pool->pool_md));
 871                                 spin_lock_irqsave(&pool->lock, flags);
 872                                 pool->no_free_space = 1;
 873                                 spin_unlock_irqrestore(&pool->lock, flags);
 874                                 return -ENOSPC;
 875                         }
 876                 }
 877         }
 878
 879         r = dm_pool_alloc_data_block(pool->pmd, result);
 880         if (r)
 881                 return r;
 882
 883         return 0;
 884 }
 885
 886 /*
 887  * If we have run out of space, queue bios until the device is
 888  * resumed, presumably after having been reloaded with more space.
 889  */
 890 static void retry_on_resume(struct bio *bio)
 891 {
 892         struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
 893         struct thin_c *tc = h->tc;
 894         struct pool *pool = tc->pool;
 895         unsigned long flags;
 896
 897         spin_lock_irqsave(&pool->lock, flags);
 898         bio_list_add(&pool->retry_on_resume_list, bio);
 899         spin_unlock_irqrestore(&pool->lock, flags);
 900 }
 901
 902 static void no_space(struct dm_bio_prison_cell *cell)
 903 {
 904         struct bio *bio;
 905         struct bio_list bios;
 906
 907         bio_list_init(&bios);
 908         dm_cell_release(cell, &bios);
 909
 910         while ((bio = bio_list_pop(&bios)))
 911                 retry_on_resume(bio);
 912 }
 913
 914 static void process_discard(struct thin_c *tc, struct bio *bio)
 915 {
 916         int r;
 917         unsigned long flags;
 918         struct pool *pool = tc->pool;
 919         struct dm_bio_prison_cell *cell, *cell2;
 920         struct dm_cell_key key, key2;
 921         dm_block_t block = get_bio_block(tc, bio);
 922         struct dm_thin_lookup_result lookup_result;
 923         struct dm_thin_new_mapping *m;
 924
 925         build_virtual_key(tc->td, block, &key);
 926         if (dm_bio_detain(tc->pool->prison, &key, bio, &cell))
 927                 return;
 928
 929         r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
 930         switch (r) {
 931         case 0:
 932                 /*
 933                  * Check nobody is fiddling with this pool block.  This can
 934                  * happen if someone's in the process of breaking sharing
 935                  * on this block.
 936                  */
 937                 build_data_key(tc->td, lookup_result.block, &key2);
 938                 if (dm_bio_detain(tc->pool->prison, &key2, bio, &cell2)) {
 939                         dm_cell_release_singleton(cell, bio);
 940                         break;
 941                 }
 942
 943                 if (io_overlaps_block(pool, bio)) {
 944                         /*
 945                          * IO may still be going to the destination block.  We must
 946                          * quiesce before we can do the removal.
 947                          */
 948                         m = get_next_mapping(pool);
 949                         m->tc = tc;
 950                         m->pass_discard = (!lookup_result.shared) && pool->pf.discard_passdown;
 951                         m->virt_block = block;
 952                         m->data_block = lookup_result.block;
 953                         m->cell = cell;
 954                         m->cell2 = cell2;
 955                         m->err = 0;
 956                         m->bio = bio;
 957
 958                         if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
 959                                 spin_lock_irqsave(&pool->lock, flags);
 960                                 list_add(&m->list, &pool->prepared_discards);
 961                                 spin_unlock_irqrestore(&pool->lock, flags);
 962                                 wake_worker(pool);
 963                         }
 964                 } else {
 965                         /*
 966                          * The DM core makes sure that the discard doesn't span
 967                          * a block boundary.  So we submit the discard of a
 968                          * partial block appropriately.
 969                          */
 970                         dm_cell_release_singleton(cell, bio);
 971                         dm_cell_release_singleton(cell2, bio);
 972                         if ((!lookup_result.shared) && pool->pf.discard_passdown)
 973                                 remap_and_issue(tc, bio, lookup_result.block);
 974                         else
 975                                 bio_endio(bio, 0);
 976                 }
 977                 break;
 978
 979         case -ENODATA:
 980                 /*
 981                  * It isn't provisioned, just forget it.
 982                  */
 983                 dm_cell_release_singleton(cell, bio);
 984                 bio_endio(bio, 0);
 985                 break;
 986
 987         default:
 988                 DMERR("discard: find block unexpectedly returned %d", r);
 989                 dm_cell_release_singleton(cell, bio);
 990                 bio_io_error(bio);
 991                 break;
 992         }
 993 }
 994
 995 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
 996                           struct dm_cell_key *key,
 997                           struct dm_thin_lookup_result *lookup_result,
 998                           struct dm_bio_prison_cell *cell)
 999 {
1000         int r;
1001         dm_block_t data_block;
1002
1003         r = alloc_data_block(tc, &data_block);
1004         switch (r) {
1005         case 0:
1006                 schedule_internal_copy(tc, block, lookup_result->block,
1007                                        data_block, cell, bio);
1008                 break;
1009
1010         case -ENOSPC:
1011                 no_space(cell);
1012                 break;
1013
1014         default:
1015                 DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
1016                 dm_cell_error(cell);
1017                 break;
1018         }
1019 }
1020
1021 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1022                                dm_block_t block,
1023                                struct dm_thin_lookup_result *lookup_result)
1024 {
1025         struct dm_bio_prison_cell *cell;
1026         struct pool *pool = tc->pool;
1027         struct dm_cell_key key;
1028
1029         /*
1030          * If cell is already occupied, then sharing is already in the process
1031          * of being broken so we have nothing further to do here.
1032          */
1033         build_data_key(tc->td, lookup_result->block, &key);
1034         if (dm_bio_detain(pool->prison, &key, bio, &cell))
1035                 return;
1036
1037         if (bio_data_dir(bio) == WRITE && bio->bi_size)
1038                 break_sharing(tc, bio, block, &key, lookup_result, cell);
1039         else {
1040                 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
1041
1042                 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1043
1044                 dm_cell_release_singleton(cell, bio);
1045                 remap_and_issue(tc, bio, lookup_result->block);
1046         }
1047 }
1048
1049 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1050                             struct dm_bio_prison_cell *cell)
1051 {
1052         int r;
1053         dm_block_t data_block;
1054
1055         /*
1056          * Remap empty bios (flushes) immediately, without provisioning.
1057          */
1058         if (!bio->bi_size) {
1059                 dm_cell_release_singleton(cell, bio);
1060                 remap_and_issue(tc, bio, 0);
1061                 return;
1062         }
1063
1064         /*
1065          * Fill read bios with zeroes and complete them immediately.
1066          */
1067         if (bio_data_dir(bio) == READ) {
1068                 zero_fill_bio(bio);
1069                 dm_cell_release_singleton(cell, bio);
1070                 bio_endio(bio, 0);
1071                 return;
1072         }
1073
1074         r = alloc_data_block(tc, &data_block);
1075         switch (r) {
1076         case 0:
1077                 if (tc->origin_dev)
1078                         schedule_external_copy(tc, block, data_block, cell, bio);
1079                 else
1080                         schedule_zero(tc, block, data_block, cell, bio);
1081                 break;
1082
1083         case -ENOSPC:
1084                 no_space(cell);
1085                 break;
1086
1087         default:
1088                 DMERR("%s: alloc_data_block() failed, error = %d", __func__, r);
1089                 set_pool_mode(tc->pool, PM_READ_ONLY);
1090                 dm_cell_error(cell);
1091                 break;
1092         }
1093 }
1094
1095 static void process_bio(struct thin_c *tc, struct bio *bio)
1096 {
1097         int r;
1098         dm_block_t block = get_bio_block(tc, bio);
1099         struct dm_bio_prison_cell *cell;
1100         struct dm_cell_key key;
1101         struct dm_thin_lookup_result lookup_result;
1102
1103         /*
1104          * If cell is already occupied, then the block is already
1105          * being provisioned so we have nothing further to do here.
1106          */
1107         build_virtual_key(tc->td, block, &key);
1108         if (dm_bio_detain(tc->pool->prison, &key, bio, &cell))
1109                 return;
1110
1111         r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1112         switch (r) {
1113         case 0:
1114                 /*
1115                  * We can release this cell now.  This thread is the only
1116                  * one that puts bios into a cell, and we know there were
1117                  * no preceding bios.
1118                  */
1119                 /*
1120                  * TODO: this will probably have to change when discard goes
1121                  * back in.
1122                  */
1123                 dm_cell_release_singleton(cell, bio);
1124
1125                 if (lookup_result.shared)
1126                         process_shared_bio(tc, bio, block, &lookup_result);
1127                 else
1128                         remap_and_issue(tc, bio, lookup_result.block);
1129                 break;
1130
1131         case -ENODATA:
1132                 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1133                         dm_cell_release_singleton(cell, bio);
1134                         remap_to_origin_and_issue(tc, bio);
1135                 } else
1136                         provision_block(tc, bio, block, cell);
1137                 break;
1138
1139         default:
1140                 DMERR("dm_thin_find_block() failed, error = %d", r);
1141                 dm_cell_release_singleton(cell, bio);
1142                 bio_io_error(bio);
1143                 break;
1144         }
1145 }
1146
1147 static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1148 {
1149         int r;
1150         int rw = bio_data_dir(bio);
1151         dm_block_t block = get_bio_block(tc, bio);
1152         struct dm_thin_lookup_result lookup_result;
1153
1154         r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1155         switch (r) {
1156         case 0:
1157                 if (lookup_result.shared && (rw == WRITE) && bio->bi_size)
1158                         bio_io_error(bio);
1159                 else
1160                         remap_and_issue(tc, bio, lookup_result.block);
1161                 break;
1162
1163         case -ENODATA:
1164                 if (rw != READ) {
1165                         bio_io_error(bio);
1166                         break;
1167                 }
1168
1169                 if (tc->origin_dev) {
1170                         remap_to_origin_and_issue(tc, bio);
1171                         break;
1172                 }
1173
1174                 zero_fill_bio(bio);
1175                 bio_endio(bio, 0);
1176                 break;
1177
1178         default:
1179                 DMERR("dm_thin_find_block() failed, error = %d", r);
1180                 bio_io_error(bio);
1181                 break;
1182         }
1183 }
1184
1185 static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1186 {
1187         bio_io_error(bio);
1188 }
1189
1190 static int need_commit_due_to_time(struct pool *pool)
1191 {
1192         return jiffies < pool->last_commit_jiffies ||
1193                jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1194 }
1195
1196 static void process_deferred_bios(struct pool *pool)
1197 {
1198         unsigned long flags;
1199         struct bio *bio;
1200         struct bio_list bios;
1201
1202         bio_list_init(&bios);
1203
1204         spin_lock_irqsave(&pool->lock, flags);
1205         bio_list_merge(&bios, &pool->deferred_bios);
1206         bio_list_init(&pool->deferred_bios);
1207         spin_unlock_irqrestore(&pool->lock, flags);
1208
1209         while ((bio = bio_list_pop(&bios))) {
1210                 struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
1211                 struct thin_c *tc = h->tc;
1212
1213                 /*
1214                  * If we've got no free new_mapping structs, and processing
1215                  * this bio might require one, we pause until there are some
1216                  * prepared mappings to process.
1217                  */
1218                 if (ensure_next_mapping(pool)) {
1219                         spin_lock_irqsave(&pool->lock, flags);
1220                         bio_list_merge(&pool->deferred_bios, &bios);
1221                         spin_unlock_irqrestore(&pool->lock, flags);
1222
1223                         break;
1224                 }
1225
1226                 if (bio->bi_rw & REQ_DISCARD)
1227                         pool->process_discard(tc, bio);
1228                 else
1229                         pool->process_bio(tc, bio);
1230         }
1231
1232         /*
1233          * If there are any deferred flush bios, we must commit
1234          * the metadata before issuing them.
1235          */
1236         bio_list_init(&bios);
1237         spin_lock_irqsave(&pool->lock, flags);
1238         bio_list_merge(&bios, &pool->deferred_flush_bios);
1239         bio_list_init(&pool->deferred_flush_bios);
1240         spin_unlock_irqrestore(&pool->lock, flags);
1241
1242         if (bio_list_empty(&bios) && !need_commit_due_to_time(pool))
1243                 return;
1244
1245         if (commit_or_fallback(pool)) {
1246                 while ((bio = bio_list_pop(&bios)))
1247                         bio_io_error(bio);
1248                 return;
1249         }
1250         pool->last_commit_jiffies = jiffies;
1251
1252         while ((bio = bio_list_pop(&bios)))
1253                 generic_make_request(bio);
1254 }
1255
1256 static void do_worker(struct work_struct *ws)
1257 {
1258         struct pool *pool = container_of(ws, struct pool, worker);
1259
1260         process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1261         process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1262         process_deferred_bios(pool);
1263 }
1264
1265 /*
1266  * We want to commit periodically so that not too much
1267  * unwritten data builds up.
1268  */
1269 static void do_waker(struct work_struct *ws)
1270 {
1271         struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1272         wake_worker(pool);
1273         queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1274 }
1275
1276 /*----------------------------------------------------------------*/
1277
1278 static enum pool_mode get_pool_mode(struct pool *pool)
1279 {
1280         return pool->pf.mode;
1281 }
1282
1283 static void set_pool_mode(struct pool *pool, enum pool_mode mode)
1284 {
1285         int r;
1286
1287         pool->pf.mode = mode;
1288
1289         switch (mode) {
1290         case PM_FAIL:
1291                 DMERR("switching pool to failure mode");
1292                 pool->process_bio = process_bio_fail;
1293                 pool->process_discard = process_bio_fail;
1294                 pool->process_prepared_mapping = process_prepared_mapping_fail;
1295                 pool->process_prepared_discard = process_prepared_discard_fail;
1296                 break;
1297
1298         case PM_READ_ONLY:
1299                 DMERR("switching pool to read-only mode");
1300                 r = dm_pool_abort_metadata(pool->pmd);
1301                 if (r) {
1302                         DMERR("aborting transaction failed");
1303                         set_pool_mode(pool, PM_FAIL);
1304                 } else {
1305                         dm_pool_metadata_read_only(pool->pmd);
1306                         pool->process_bio = process_bio_read_only;
1307                         pool->process_discard = process_discard;
1308                         pool->process_prepared_mapping = process_prepared_mapping_fail;
1309                         pool->process_prepared_discard = process_prepared_discard_passdown;
1310                 }
1311                 break;
1312
1313         case PM_WRITE:
1314                 pool->process_bio = process_bio;
1315                 pool->process_discard = process_discard;
1316                 pool->process_prepared_mapping = process_prepared_mapping;
1317                 pool->process_prepared_discard = process_prepared_discard;
1318                 break;
1319         }
1320 }
1321
1322 /*----------------------------------------------------------------*/
1323
1324 /*
1325  * Mapping functions.
1326  */
1327
1328 /*
1329  * Called only while mapping a thin bio to hand it over to the workqueue.
1330  */
1331 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1332 {
1333         unsigned long flags;
1334         struct pool *pool = tc->pool;
1335
1336         spin_lock_irqsave(&pool->lock, flags);
1337         bio_list_add(&pool->deferred_bios, bio);
1338         spin_unlock_irqrestore(&pool->lock, flags);
1339
1340         wake_worker(pool);
1341 }
1342
1343 static struct dm_thin_endio_hook *thin_hook_bio(struct thin_c *tc, struct bio *bio)
1344 {
1345         struct pool *pool = tc->pool;
1346         struct dm_thin_endio_hook *h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO);
1347
1348         h->tc = tc;
1349         h->shared_read_entry = NULL;
1350         h->all_io_entry = bio->bi_rw & REQ_DISCARD ? NULL : dm_deferred_entry_inc(pool->all_io_ds);
1351         h->overwrite_mapping = NULL;
1352
1353         return h;
1354 }
1355
1356 /*
1357  * Non-blocking function called from the thin target's map function.
1358  */
1359 static int thin_bio_map(struct dm_target *ti, struct bio *bio,
1360                         union map_info *map_context)
1361 {
1362         int r;
1363         struct thin_c *tc = ti->private;
1364         dm_block_t block = get_bio_block(tc, bio);
1365         struct dm_thin_device *td = tc->td;
1366         struct dm_thin_lookup_result result;
1367
1368         map_context->ptr = thin_hook_bio(tc, bio);
1369
1370         if (get_pool_mode(tc->pool) == PM_FAIL) {
1371                 bio_io_error(bio);
1372                 return DM_MAPIO_SUBMITTED;
1373         }
1374
1375         if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
1376                 thin_defer_bio(tc, bio);
1377                 return DM_MAPIO_SUBMITTED;
1378         }
1379
1380         r = dm_thin_find_block(td, block, 0, &result);
1381
1382         /*
1383          * Note that we defer readahead too.
1384          */
1385         switch (r) {
1386         case 0:
1387                 if (unlikely(result.shared)) {
1388                         /*
1389                          * We have a race condition here between the
1390                          * result.shared value returned by the lookup and
1391                          * snapshot creation, which may cause new
1392                          * sharing.
1393                          *
1394                          * To avoid this always quiesce the origin before
1395                          * taking the snap.  You want to do this anyway to
1396                          * ensure a consistent application view
1397                          * (i.e. lockfs).
1398                          *
1399                          * More distant ancestors are irrelevant. The
1400                          * shared flag will be set in their case.
1401                          */
1402                         thin_defer_bio(tc, bio);
1403                         r = DM_MAPIO_SUBMITTED;
1404                 } else {
1405                         remap(tc, bio, result.block);
1406                         r = DM_MAPIO_REMAPPED;
1407                 }
1408                 break;
1409
1410         case -ENODATA:
1411                 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
1412                         /*
1413                          * This block isn't provisioned, and we have no way
1414                          * of doing so.  Just error it.
1415                          */
1416                         bio_io_error(bio);
1417                         r = DM_MAPIO_SUBMITTED;
1418                         break;
1419                 }
1420                 /* fall through */
1421
1422         case -EWOULDBLOCK:
1423                 /*
1424                  * In future, the failed dm_thin_find_block above could
1425                  * provide the hint to load the metadata into cache.
1426                  */
1427                 thin_defer_bio(tc, bio);
1428                 r = DM_MAPIO_SUBMITTED;
1429                 break;
1430
1431         default:
1432                 /*
1433                  * Must always call bio_io_error on failure.
1434                  * dm_thin_find_block can fail with -EINVAL if the
1435                  * pool is switched to fail-io mode.
1436                  */
1437                 bio_io_error(bio);
1438                 r = DM_MAPIO_SUBMITTED;
1439                 break;
1440         }
1441
1442         return r;
1443 }
1444
1445 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1446 {
1447         int r;
1448         unsigned long flags;
1449         struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1450
1451         spin_lock_irqsave(&pt->pool->lock, flags);
1452         r = !bio_list_empty(&pt->pool->retry_on_resume_list);
1453         spin_unlock_irqrestore(&pt->pool->lock, flags);
1454
1455         if (!r) {
1456                 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1457                 r = bdi_congested(&q->backing_dev_info, bdi_bits);
1458         }
1459
1460         return r;
1461 }
1462
1463 static void __requeue_bios(struct pool *pool)
1464 {
1465         bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
1466         bio_list_init(&pool->retry_on_resume_list);
1467 }
1468
1469 /*----------------------------------------------------------------
1470  * Binding of control targets to a pool object
1471  *--------------------------------------------------------------*/
1472 static bool data_dev_supports_discard(struct pool_c *pt)
1473 {
1474         struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1475
1476         return q && blk_queue_discard(q);
1477 }
1478
1479 /*
1480  * If discard_passdown was enabled verify that the data device
1481  * supports discards.  Disable discard_passdown if not.
1482  */
1483 static void disable_passdown_if_not_supported(struct pool_c *pt)
1484 {
1485         struct pool *pool = pt->pool;
1486         struct block_device *data_bdev = pt->data_dev->bdev;
1487         struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
1488         sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
1489         const char *reason = NULL;
1490         char buf[BDEVNAME_SIZE];
1491
1492         if (!pt->adjusted_pf.discard_passdown)
1493                 return;
1494
1495         if (!data_dev_supports_discard(pt))
1496                 reason = "discard unsupported";
1497
1498         else if (data_limits->max_discard_sectors < pool->sectors_per_block)
1499                 reason = "max discard sectors smaller than a block";
1500
1501         else if (data_limits->discard_granularity > block_size)
1502                 reason = "discard granularity larger than a block";
1503
1504         else if (block_size & (data_limits->discard_granularity - 1))
1505                 reason = "discard granularity not a factor of block size";
1506
1507         if (reason) {
1508                 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
1509                 pt->adjusted_pf.discard_passdown = false;
1510         }
1511 }
1512
1513 static int bind_control_target(struct pool *pool, struct dm_target *ti)
1514 {
1515         struct pool_c *pt = ti->private;
1516
1517         /*
1518          * We want to make sure that degraded pools are never upgraded.
1519          */
1520         enum pool_mode old_mode = pool->pf.mode;
1521         enum pool_mode new_mode = pt->adjusted_pf.mode;
1522
1523         if (old_mode > new_mode)
1524                 new_mode = old_mode;
1525
1526         pool->ti = ti;
1527         pool->low_water_blocks = pt->low_water_blocks;
1528         pool->pf = pt->adjusted_pf;
1529
1530         set_pool_mode(pool, new_mode);
1531
1532         return 0;
1533 }
1534
1535 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
1536 {
1537         if (pool->ti == ti)
1538                 pool->ti = NULL;
1539 }
1540
1541 /*----------------------------------------------------------------
1542  * Pool creation
1543  *--------------------------------------------------------------*/
1544 /* Initialize pool features. */
1545 static void pool_features_init(struct pool_features *pf)
1546 {
1547         pf->mode = PM_WRITE;
1548         pf->zero_new_blocks = true;
1549         pf->discard_enabled = true;
1550         pf->discard_passdown = true;
1551 }
1552
1553 static void __pool_destroy(struct pool *pool)
1554 {
1555         __pool_table_remove(pool);
1556
1557         if (dm_pool_metadata_close(pool->pmd) < 0)
1558                 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1559
1560         dm_bio_prison_destroy(pool->prison);
1561         dm_kcopyd_client_destroy(pool->copier);
1562
1563         if (pool->wq)
1564                 destroy_workqueue(pool->wq);
1565
1566         if (pool->next_mapping)
1567                 mempool_free(pool->next_mapping, pool->mapping_pool);
1568         mempool_destroy(pool->mapping_pool);
1569         mempool_destroy(pool->endio_hook_pool);
1570         dm_deferred_set_destroy(pool->shared_read_ds);
1571         dm_deferred_set_destroy(pool->all_io_ds);
1572         kfree(pool);
1573 }
1574
1575 static struct kmem_cache *_new_mapping_cache;
1576 static struct kmem_cache *_endio_hook_cache;
1577
1578 static struct pool *pool_create(struct mapped_device *pool_md,
1579                                 struct block_device *metadata_dev,
1580                                 unsigned long block_size,
1581                                 int read_only, char **error)
1582 {
1583         int r;
1584         void *err_p;
1585         struct pool *pool;
1586         struct dm_pool_metadata *pmd;
1587         bool format_device = read_only ? false : true;
1588
1589         pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
1590         if (IS_ERR(pmd)) {
1591                 *error = "Error creating metadata object";
1592                 return (struct pool *)pmd;
1593         }
1594
1595         pool = kmalloc(sizeof(*pool), GFP_KERNEL);
1596         if (!pool) {
1597                 *error = "Error allocating memory for pool";
1598                 err_p = ERR_PTR(-ENOMEM);
1599                 goto bad_pool;
1600         }
1601
1602         pool->pmd = pmd;
1603         pool->sectors_per_block = block_size;
1604         if (block_size & (block_size - 1))
1605                 pool->sectors_per_block_shift = -1;
1606         else
1607                 pool->sectors_per_block_shift = __ffs(block_size);
1608         pool->low_water_blocks = 0;
1609         pool_features_init(&pool->pf);
1610         pool->prison = dm_bio_prison_create(PRISON_CELLS);
1611         if (!pool->prison) {
1612                 *error = "Error creating pool's bio prison";
1613                 err_p = ERR_PTR(-ENOMEM);
1614                 goto bad_prison;
1615         }
1616
1617         pool->copier = dm_kcopyd_client_create();
1618         if (IS_ERR(pool->copier)) {
1619                 r = PTR_ERR(pool->copier);
1620                 *error = "Error creating pool's kcopyd client";
1621                 err_p = ERR_PTR(r);
1622                 goto bad_kcopyd_client;
1623         }
1624
1625         /*
1626          * Create singlethreaded workqueue that will service all devices
1627          * that use this metadata.
1628          */
1629         pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1630         if (!pool->wq) {
1631                 *error = "Error creating pool's workqueue";
1632                 err_p = ERR_PTR(-ENOMEM);
1633                 goto bad_wq;
1634         }
1635
1636         INIT_WORK(&pool->worker, do_worker);
1637         INIT_DELAYED_WORK(&pool->waker, do_waker);
1638         spin_lock_init(&pool->lock);
1639         bio_list_init(&pool->deferred_bios);
1640         bio_list_init(&pool->deferred_flush_bios);
1641         INIT_LIST_HEAD(&pool->prepared_mappings);
1642         INIT_LIST_HEAD(&pool->prepared_discards);
1643         pool->low_water_triggered = 0;
1644         pool->no_free_space = 0;
1645         bio_list_init(&pool->retry_on_resume_list);
1646
1647         pool->shared_read_ds = dm_deferred_set_create();
1648         if (!pool->shared_read_ds) {
1649                 *error = "Error creating pool's shared read deferred set";
1650                 err_p = ERR_PTR(-ENOMEM);
1651                 goto bad_shared_read_ds;
1652         }
1653
1654         pool->all_io_ds = dm_deferred_set_create();
1655         if (!pool->all_io_ds) {
1656                 *error = "Error creating pool's all io deferred set";
1657                 err_p = ERR_PTR(-ENOMEM);
1658                 goto bad_all_io_ds;
1659         }
1660
1661         pool->next_mapping = NULL;
1662         pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
1663                                                       _new_mapping_cache);
1664         if (!pool->mapping_pool) {
1665                 *error = "Error creating pool's mapping mempool";
1666                 err_p = ERR_PTR(-ENOMEM);
1667                 goto bad_mapping_pool;
1668         }
1669
1670         pool->endio_hook_pool = mempool_create_slab_pool(ENDIO_HOOK_POOL_SIZE,
1671                                                          _endio_hook_cache);
1672         if (!pool->endio_hook_pool) {
1673                 *error = "Error creating pool's endio_hook mempool";
1674                 err_p = ERR_PTR(-ENOMEM);
1675                 goto bad_endio_hook_pool;
1676         }
1677         pool->ref_count = 1;
1678         pool->last_commit_jiffies = jiffies;
1679         pool->pool_md = pool_md;
1680         pool->md_dev = metadata_dev;
1681         __pool_table_insert(pool);
1682
1683         return pool;
1684
1685 bad_endio_hook_pool:
1686         mempool_destroy(pool->mapping_pool);
1687 bad_mapping_pool:
1688         dm_deferred_set_destroy(pool->all_io_ds);
1689 bad_all_io_ds:
1690         dm_deferred_set_destroy(pool->shared_read_ds);
1691 bad_shared_read_ds:
1692         destroy_workqueue(pool->wq);
1693 bad_wq:
1694         dm_kcopyd_client_destroy(pool->copier);
1695 bad_kcopyd_client:
1696         dm_bio_prison_destroy(pool->prison);
1697 bad_prison:
1698         kfree(pool);
1699 bad_pool:
1700         if (dm_pool_metadata_close(pmd))
1701                 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1702
1703         return err_p;
1704 }
1705
1706 static void __pool_inc(struct pool *pool)
1707 {
1708         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1709         pool->ref_count++;
1710 }
1711
1712 static void __pool_dec(struct pool *pool)
1713 {
1714         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1715         BUG_ON(!pool->ref_count);
1716         if (!--pool->ref_count)
1717                 __pool_destroy(pool);
1718 }
1719
1720 static struct pool *__pool_find(struct mapped_device *pool_md,
1721                                 struct block_device *metadata_dev,
1722                                 unsigned long block_size, int read_only,
1723                                 char **error, int *created)
1724 {
1725         struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
1726
1727         if (pool) {
1728                 if (pool->pool_md != pool_md) {
1729                         *error = "metadata device already in use by a pool";
1730                         return ERR_PTR(-EBUSY);
1731                 }
1732                 __pool_inc(pool);
1733
1734         } else {
1735                 pool = __pool_table_lookup(pool_md);
1736                 if (pool) {
1737                         if (pool->md_dev != metadata_dev) {
1738                                 *error = "different pool cannot replace a pool";
1739                                 return ERR_PTR(-EINVAL);
1740                         }
1741                         __pool_inc(pool);
1742
1743                 } else {
1744                         pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
1745                         *created = 1;
1746                 }
1747         }
1748
1749         return pool;
1750 }
1751
1752 /*----------------------------------------------------------------
1753  * Pool target methods
1754  *--------------------------------------------------------------*/
1755 static void pool_dtr(struct dm_target *ti)
1756 {
1757         struct pool_c *pt = ti->private;
1758
1759         mutex_lock(&dm_thin_pool_table.mutex);
1760
1761         unbind_control_target(pt->pool, ti);
1762         __pool_dec(pt->pool);
1763         dm_put_device(ti, pt->metadata_dev);
1764         dm_put_device(ti, pt->data_dev);
1765         kfree(pt);
1766
1767         mutex_unlock(&dm_thin_pool_table.mutex);
1768 }
1769
1770 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
1771                                struct dm_target *ti)
1772 {
1773         int r;
1774         unsigned argc;
1775         const char *arg_name;
1776
1777         static struct dm_arg _args[] = {
1778                 {0, 3, "Invalid number of pool feature arguments"},
1779         };
1780
1781         /*
1782          * No feature arguments supplied.
1783          */
1784         if (!as->argc)
1785                 return 0;
1786
1787         r = dm_read_arg_group(_args, as, &argc, &ti->error);
1788         if (r)
1789                 return -EINVAL;
1790
1791         while (argc && !r) {
1792                 arg_name = dm_shift_arg(as);
1793                 argc--;
1794
1795                 if (!strcasecmp(arg_name, "skip_block_zeroing"))
1796                         pf->zero_new_blocks = false;
1797
1798                 else if (!strcasecmp(arg_name, "ignore_discard"))
1799                         pf->discard_enabled = false;
1800
1801                 else if (!strcasecmp(arg_name, "no_discard_passdown"))
1802                         pf->discard_passdown = false;
1803
1804                 else if (!strcasecmp(arg_name, "read_only"))
1805                         pf->mode = PM_READ_ONLY;
1806
1807                 else {
1808                         ti->error = "Unrecognised pool feature requested";
1809                         r = -EINVAL;
1810                         break;
1811                 }
1812         }
1813
1814         return r;
1815 }
1816
1817 /*
1818  * thin-pool <metadata dev> <data dev>
1819  *           <data block size (sectors)>
1820  *           <low water mark (blocks)>
1821  *           [<#feature args> [<arg>]*]
1822  *
1823  * Optional feature arguments are:
1824  *           skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1825  *           ignore_discard: disable discard
1826  *           no_discard_passdown: don't pass discards down to the data device
1827  */
1828 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
1829 {
1830         int r, pool_created = 0;
1831         struct pool_c *pt;
1832         struct pool *pool;
1833         struct pool_features pf;
1834         struct dm_arg_set as;
1835         struct dm_dev *data_dev;
1836         unsigned long block_size;
1837         dm_block_t low_water_blocks;
1838         struct dm_dev *metadata_dev;
1839         sector_t metadata_dev_size;
1840         char b[BDEVNAME_SIZE];
1841
1842         /*
1843          * FIXME Remove validation from scope of lock.
1844          */
1845         mutex_lock(&dm_thin_pool_table.mutex);
1846
1847         if (argc < 4) {
1848                 ti->error = "Invalid argument count";
1849                 r = -EINVAL;
1850                 goto out_unlock;
1851         }
1852         as.argc = argc;
1853         as.argv = argv;
1854
1855         r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev);
1856         if (r) {
1857                 ti->error = "Error opening metadata block device";
1858                 goto out_unlock;
1859         }
1860
1861         metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT;
1862         if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
1863                 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1864                        bdevname(metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
1865
1866         r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
1867         if (r) {
1868                 ti->error = "Error getting data device";
1869                 goto out_metadata;
1870         }
1871
1872         if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
1873             block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
1874             block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
1875             block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
1876                 ti->error = "Invalid block size";
1877                 r = -EINVAL;
1878                 goto out;
1879         }
1880
1881         if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
1882                 ti->error = "Invalid low water mark";
1883                 r = -EINVAL;
1884                 goto out;
1885         }
1886
1887         /*
1888          * Set default pool features.
1889          */
1890         pool_features_init(&pf);
1891
1892         dm_consume_args(&as, 4);
1893         r = parse_pool_features(&as, &pf, ti);
1894         if (r)
1895                 goto out;
1896
1897         pt = kzalloc(sizeof(*pt), GFP_KERNEL);
1898         if (!pt) {
1899                 r = -ENOMEM;
1900                 goto out;
1901         }
1902
1903         pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
1904                            block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
1905         if (IS_ERR(pool)) {
1906                 r = PTR_ERR(pool);
1907                 goto out_free_pt;
1908         }
1909
1910         /*
1911          * 'pool_created' reflects whether this is the first table load.
1912          * Top level discard support is not allowed to be changed after
1913          * initial load.  This would require a pool reload to trigger thin
1914          * device changes.
1915          */
1916         if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
1917                 ti->error = "Discard support cannot be disabled once enabled";
1918                 r = -EINVAL;
1919                 goto out_flags_changed;
1920         }
1921
1922         pt->pool = pool;
1923         pt->ti = ti;
1924         pt->metadata_dev = metadata_dev;
1925         pt->data_dev = data_dev;
1926         pt->low_water_blocks = low_water_blocks;
1927         pt->adjusted_pf = pt->requested_pf = pf;
1928         ti->num_flush_requests = 1;
1929
1930         /*
1931          * Only need to enable discards if the pool should pass
1932          * them down to the data device.  The thin device's discard
1933          * processing will cause mappings to be removed from the btree.
1934          */
1935         if (pf.discard_enabled && pf.discard_passdown) {
1936                 ti->num_discard_requests = 1;
1937
1938                 /*
1939                  * Setting 'discards_supported' circumvents the normal
1940                  * stacking of discard limits (this keeps the pool and
1941                  * thin devices' discard limits consistent).
1942                  */
1943                 ti->discards_supported = true;
1944                 ti->discard_zeroes_data_unsupported = true;
1945         }
1946         ti->private = pt;
1947
1948         pt->callbacks.congested_fn = pool_is_congested;
1949         dm_table_add_target_callbacks(ti->table, &pt->callbacks);
1950
1951         mutex_unlock(&dm_thin_pool_table.mutex);
1952
1953         return 0;
1954
1955 out_flags_changed:
1956         __pool_dec(pool);
1957 out_free_pt:
1958         kfree(pt);
1959 out:
1960         dm_put_device(ti, data_dev);
1961 out_metadata:
1962         dm_put_device(ti, metadata_dev);
1963 out_unlock:
1964         mutex_unlock(&dm_thin_pool_table.mutex);
1965
1966         return r;
1967 }
1968
1969 static int pool_map(struct dm_target *ti, struct bio *bio,
1970                     union map_info *map_context)
1971 {
1972         int r;
1973         struct pool_c *pt = ti->private;
1974         struct pool *pool = pt->pool;
1975         unsigned long flags;
1976
1977         /*
1978          * As this is a singleton target, ti->begin is always zero.
1979          */
1980         spin_lock_irqsave(&pool->lock, flags);
1981         bio->bi_bdev = pt->data_dev->bdev;
1982         r = DM_MAPIO_REMAPPED;
1983         spin_unlock_irqrestore(&pool->lock, flags);
1984
1985         return r;
1986 }
1987
1988 /*
1989  * Retrieves the number of blocks of the data device from
1990  * the superblock and compares it to the actual device size,
1991  * thus resizing the data device in case it has grown.
1992  *
1993  * This both copes with opening preallocated data devices in the ctr
1994  * being followed by a resume
1995  * -and-
1996  * calling the resume method individually after userspace has
1997  * grown the data device in reaction to a table event.
1998  */
1999 static int pool_preresume(struct dm_target *ti)
2000 {
2001         int r;
2002         struct pool_c *pt = ti->private;
2003         struct pool *pool = pt->pool;
2004         sector_t data_size = ti->len;
2005         dm_block_t sb_data_size;
2006
2007         /*
2008          * Take control of the pool object.
2009          */
2010         r = bind_control_target(pool, ti);
2011         if (r)
2012                 return r;
2013
2014         (void) sector_div(data_size, pool->sectors_per_block);
2015
2016         r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2017         if (r) {
2018                 DMERR("failed to retrieve data device size");
2019                 return r;
2020         }
2021
2022         if (data_size < sb_data_size) {
2023                 DMERR("pool target too small, is %llu blocks (expected %llu)",
2024                       (unsigned long long)data_size, sb_data_size);
2025                 return -EINVAL;
2026
2027         } else if (data_size > sb_data_size) {
2028                 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2029                 if (r) {
2030                         DMERR("failed to resize data device");
2031                         /* FIXME Stricter than necessary: Rollback transaction instead here */
2032                         set_pool_mode(pool, PM_READ_ONLY);
2033                         return r;
2034                 }
2035
2036                 (void) commit_or_fallback(pool);
2037         }
2038
2039         return 0;
2040 }
2041
2042 static void pool_resume(struct dm_target *ti)
2043 {
2044         struct pool_c *pt = ti->private;
2045         struct pool *pool = pt->pool;
2046         unsigned long flags;
2047
2048         spin_lock_irqsave(&pool->lock, flags);
2049         pool->low_water_triggered = 0;
2050         pool->no_free_space = 0;
2051         __requeue_bios(pool);
2052         spin_unlock_irqrestore(&pool->lock, flags);
2053
2054         do_waker(&pool->waker.work);
2055 }
2056
2057 static void pool_postsuspend(struct dm_target *ti)
2058 {
2059         struct pool_c *pt = ti->private;
2060         struct pool *pool = pt->pool;
2061
2062         cancel_delayed_work(&pool->waker);
2063         flush_workqueue(pool->wq);
2064         (void) commit_or_fallback(pool);
2065 }
2066
2067 static int check_arg_count(unsigned argc, unsigned args_required)
2068 {
2069         if (argc != args_required) {
2070                 DMWARN("Message received with %u arguments instead of %u.",
2071                        argc, args_required);
2072                 return -EINVAL;
2073         }
2074
2075         return 0;
2076 }
2077
2078 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
2079 {
2080         if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
2081             *dev_id <= MAX_DEV_ID)
2082                 return 0;
2083
2084         if (warning)
2085                 DMWARN("Message received with invalid device id: %s", arg);
2086
2087         return -EINVAL;
2088 }
2089
2090 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
2091 {
2092         dm_thin_id dev_id;
2093         int r;
2094
2095         r = check_arg_count(argc, 2);
2096         if (r)
2097                 return r;
2098
2099         r = read_dev_id(argv[1], &dev_id, 1);
2100         if (r)
2101                 return r;
2102
2103         r = dm_pool_create_thin(pool->pmd, dev_id);
2104         if (r) {
2105                 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2106                        argv[1]);
2107                 return r;
2108         }
2109
2110         return 0;
2111 }
2112
2113 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2114 {
2115         dm_thin_id dev_id;
2116         dm_thin_id origin_dev_id;
2117         int r;
2118
2119         r = check_arg_count(argc, 3);
2120         if (r)
2121                 return r;
2122
2123         r = read_dev_id(argv[1], &dev_id, 1);
2124         if (r)
2125                 return r;
2126
2127         r = read_dev_id(argv[2], &origin_dev_id, 1);
2128         if (r)
2129                 return r;
2130
2131         r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
2132         if (r) {
2133                 DMWARN("Creation of new snapshot %s of device %s failed.",
2134                        argv[1], argv[2]);
2135                 return r;
2136         }
2137
2138         return 0;
2139 }
2140
2141 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2142 {
2143         dm_thin_id dev_id;
2144         int r;
2145
2146         r = check_arg_count(argc, 2);
2147         if (r)
2148                 return r;
2149
2150         r = read_dev_id(argv[1], &dev_id, 1);
2151         if (r)
2152                 return r;
2153
2154         r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2155         if (r)
2156                 DMWARN("Deletion of thin device %s failed.", argv[1]);
2157
2158         return r;
2159 }
2160
2161 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2162 {
2163         dm_thin_id old_id, new_id;
2164         int r;
2165
2166         r = check_arg_count(argc, 3);
2167         if (r)
2168                 return r;
2169
2170         if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2171                 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2172                 return -EINVAL;
2173         }
2174
2175         if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2176                 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2177                 return -EINVAL;
2178         }
2179
2180         r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2181         if (r) {
2182                 DMWARN("Failed to change transaction id from %s to %s.",
2183                        argv[1], argv[2]);
2184                 return r;
2185         }
2186
2187         return 0;
2188 }
2189
2190 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2191 {
2192         int r;
2193
2194         r = check_arg_count(argc, 1);
2195         if (r)
2196                 return r;
2197
2198         (void) commit_or_fallback(pool);
2199
2200         r = dm_pool_reserve_metadata_snap(pool->pmd);
2201         if (r)
2202                 DMWARN("reserve_metadata_snap message failed.");
2203
2204         return r;
2205 }
2206
2207 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2208 {
2209         int r;
2210
2211         r = check_arg_count(argc, 1);
2212         if (r)
2213                 return r;
2214
2215         r = dm_pool_release_metadata_snap(pool->pmd);
2216         if (r)
2217                 DMWARN("release_metadata_snap message failed.");
2218
2219         return r;
2220 }
2221
2222 /*
2223  * Messages supported:
2224  *   create_thin        <dev_id>
2225  *   create_snap        <dev_id> <origin_id>
2226  *   delete             <dev_id>
2227  *   trim               <dev_id> <new_size_in_sectors>
2228  *   set_transaction_id <current_trans_id> <new_trans_id>
2229  *   reserve_metadata_snap
2230  *   release_metadata_snap
2231  */
2232 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2233 {
2234         int r = -EINVAL;
2235         struct pool_c *pt = ti->private;
2236         struct pool *pool = pt->pool;
2237
2238         if (!strcasecmp(argv[0], "create_thin"))
2239                 r = process_create_thin_mesg(argc, argv, pool);
2240
2241         else if (!strcasecmp(argv[0], "create_snap"))
2242                 r = process_create_snap_mesg(argc, argv, pool);
2243
2244         else if (!strcasecmp(argv[0], "delete"))
2245                 r = process_delete_mesg(argc, argv, pool);
2246
2247         else if (!strcasecmp(argv[0], "set_transaction_id"))
2248                 r = process_set_transaction_id_mesg(argc, argv, pool);
2249
2250         else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
2251                 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
2252
2253         else if (!strcasecmp(argv[0], "release_metadata_snap"))
2254                 r = process_release_metadata_snap_mesg(argc, argv, pool);
2255
2256         else
2257                 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2258
2259         if (!r)
2260                 (void) commit_or_fallback(pool);
2261
2262         return r;
2263 }
2264
2265 static void emit_flags(struct pool_features *pf, char *result,
2266                        unsigned sz, unsigned maxlen)
2267 {
2268         unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
2269                 !pf->discard_passdown + (pf->mode == PM_READ_ONLY);
2270         DMEMIT("%u ", count);
2271
2272         if (!pf->zero_new_blocks)
2273                 DMEMIT("skip_block_zeroing ");
2274
2275         if (!pf->discard_enabled)
2276                 DMEMIT("ignore_discard ");
2277
2278         if (!pf->discard_passdown)
2279                 DMEMIT("no_discard_passdown ");
2280
2281         if (pf->mode == PM_READ_ONLY)
2282                 DMEMIT("read_only ");
2283 }
2284
2285 /*
2286  * Status line is:
2287  *    <transaction id> <used metadata sectors>/<total metadata sectors>
2288  *    <used data sectors>/<total data sectors> <held metadata root>
2289  */
2290 static int pool_status(struct dm_target *ti, status_type_t type,
2291                        unsigned status_flags, char *result, unsigned maxlen)
2292 {
2293         int r;
2294         unsigned sz = 0;
2295         uint64_t transaction_id;
2296         dm_block_t nr_free_blocks_data;
2297         dm_block_t nr_free_blocks_metadata;
2298         dm_block_t nr_blocks_data;
2299         dm_block_t nr_blocks_metadata;
2300         dm_block_t held_root;
2301         char buf[BDEVNAME_SIZE];
2302         char buf2[BDEVNAME_SIZE];
2303         struct pool_c *pt = ti->private;
2304         struct pool *pool = pt->pool;
2305
2306         switch (type) {
2307         case STATUSTYPE_INFO:
2308                 if (get_pool_mode(pool) == PM_FAIL) {
2309                         DMEMIT("Fail");
2310                         break;
2311                 }
2312
2313                 /* Commit to ensure statistics aren't out-of-date */
2314                 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
2315                         (void) commit_or_fallback(pool);
2316
2317                 r = dm_pool_get_metadata_transaction_id(pool->pmd,
2318                                                         &transaction_id);
2319                 if (r)
2320                         return r;
2321
2322                 r = dm_pool_get_free_metadata_block_count(pool->pmd,
2323                                                           &nr_free_blocks_metadata);
2324                 if (r)
2325                         return r;
2326
2327                 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2328                 if (r)
2329                         return r;
2330
2331                 r = dm_pool_get_free_block_count(pool->pmd,
2332                                                  &nr_free_blocks_data);
2333                 if (r)
2334                         return r;
2335
2336                 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2337                 if (r)
2338                         return r;
2339
2340                 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
2341                 if (r)
2342                         return r;
2343
2344                 DMEMIT("%llu %llu/%llu %llu/%llu ",
2345                        (unsigned long long)transaction_id,
2346                        (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2347                        (unsigned long long)nr_blocks_metadata,
2348                        (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
2349                        (unsigned long long)nr_blocks_data);
2350
2351                 if (held_root)
2352                         DMEMIT("%llu ", held_root);
2353                 else
2354                         DMEMIT("- ");
2355
2356                 if (pool->pf.mode == PM_READ_ONLY)
2357                         DMEMIT("ro ");
2358                 else
2359                         DMEMIT("rw ");
2360
2361                 if (pool->pf.discard_enabled && pool->pf.discard_passdown)
2362                         DMEMIT("discard_passdown");
2363                 else
2364                         DMEMIT("no_discard_passdown");
2365
2366                 break;
2367
2368         case STATUSTYPE_TABLE:
2369                 DMEMIT("%s %s %lu %llu ",
2370                        format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
2371                        format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
2372                        (unsigned long)pool->sectors_per_block,
2373                        (unsigned long long)pt->low_water_blocks);
2374                 emit_flags(&pt->requested_pf, result, sz, maxlen);
2375                 break;
2376         }
2377
2378         return 0;
2379 }
2380
2381 static int pool_iterate_devices(struct dm_target *ti,
2382                                 iterate_devices_callout_fn fn, void *data)
2383 {
2384         struct pool_c *pt = ti->private;
2385
2386         return fn(ti, pt->data_dev, 0, ti->len, data);
2387 }
2388
2389 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
2390                       struct bio_vec *biovec, int max_size)
2391 {
2392         struct pool_c *pt = ti->private;
2393         struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2394
2395         if (!q->merge_bvec_fn)
2396                 return max_size;
2397
2398         bvm->bi_bdev = pt->data_dev->bdev;
2399
2400         return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2401 }
2402
2403 static bool block_size_is_power_of_two(struct pool *pool)
2404 {
2405         return pool->sectors_per_block_shift >= 0;
2406 }
2407
2408 static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
2409 {
2410         struct pool *pool = pt->pool;
2411         struct queue_limits *data_limits;
2412
2413         limits->max_discard_sectors = pool->sectors_per_block;
2414
2415         /*
2416          * discard_granularity is just a hint, and not enforced.
2417          */
2418         if (pt->adjusted_pf.discard_passdown) {
2419                 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
2420                 limits->discard_granularity = data_limits->discard_granularity;
2421         } else if (block_size_is_power_of_two(pool))
2422                 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
2423         else
2424                 /*
2425                  * Use largest power of 2 that is a factor of sectors_per_block
2426                  * but at least DATA_DEV_BLOCK_SIZE_MIN_SECTORS.
2427                  */
2428                 limits->discard_granularity = max(1 << (ffs(pool->sectors_per_block) - 1),
2429                                                   DATA_DEV_BLOCK_SIZE_MIN_SECTORS) << SECTOR_SHIFT;
2430 }
2431
2432 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
2433 {
2434         struct pool_c *pt = ti->private;
2435         struct pool *pool = pt->pool;
2436
2437         blk_limits_io_min(limits, 0);
2438         blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2439
2440         /*
2441          * pt->adjusted_pf is a staging area for the actual features to use.
2442          * They get transferred to the live pool in bind_control_target()
2443          * called from pool_preresume().
2444          */
2445         if (!pt->adjusted_pf.discard_enabled)
2446                 return;
2447
2448         disable_passdown_if_not_supported(pt);
2449
2450         set_discard_limits(pt, limits);
2451 }
2452
2453 static struct target_type pool_target = {
2454         .name = "thin-pool",
2455         .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
2456                     DM_TARGET_IMMUTABLE,
2457         .version = {1, 5, 0},
2458         .module = THIS_MODULE,
2459         .ctr = pool_ctr,
2460         .dtr = pool_dtr,
2461         .map = pool_map,
2462         .postsuspend = pool_postsuspend,
2463         .preresume = pool_preresume,
2464         .resume = pool_resume,
2465         .message = pool_message,
2466         .status = pool_status,
2467         .merge = pool_merge,
2468         .iterate_devices = pool_iterate_devices,
2469         .io_hints = pool_io_hints,
2470 };
2471
2472 /*----------------------------------------------------------------
2473  * Thin target methods
2474  *--------------------------------------------------------------*/
2475 static void thin_dtr(struct dm_target *ti)
2476 {
2477         struct thin_c *tc = ti->private;
2478
2479         mutex_lock(&dm_thin_pool_table.mutex);
2480
2481         __pool_dec(tc->pool);
2482         dm_pool_close_thin_device(tc->td);
2483         dm_put_device(ti, tc->pool_dev);
2484         if (tc->origin_dev)
2485                 dm_put_device(ti, tc->origin_dev);
2486         kfree(tc);
2487
2488         mutex_unlock(&dm_thin_pool_table.mutex);
2489 }
2490
2491 /*
2492  * Thin target parameters:
2493  *
2494  * <pool_dev> <dev_id> [origin_dev]
2495  *
2496  * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2497  * dev_id: the internal device identifier
2498  * origin_dev: a device external to the pool that should act as the origin
2499  *
2500  * If the pool device has discards disabled, they get disabled for the thin
2501  * device as well.
2502  */
2503 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
2504 {
2505         int r;
2506         struct thin_c *tc;
2507         struct dm_dev *pool_dev, *origin_dev;
2508         struct mapped_device *pool_md;
2509
2510         mutex_lock(&dm_thin_pool_table.mutex);
2511
2512         if (argc != 2 && argc != 3) {
2513                 ti->error = "Invalid argument count";
2514                 r = -EINVAL;
2515                 goto out_unlock;
2516         }
2517
2518         tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
2519         if (!tc) {
2520                 ti->error = "Out of memory";
2521                 r = -ENOMEM;
2522                 goto out_unlock;
2523         }
2524
2525         if (argc == 3) {
2526                 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
2527                 if (r) {
2528                         ti->error = "Error opening origin device";
2529                         goto bad_origin_dev;
2530                 }
2531                 tc->origin_dev = origin_dev;
2532         }
2533
2534         r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
2535         if (r) {
2536                 ti->error = "Error opening pool device";
2537                 goto bad_pool_dev;
2538         }
2539         tc->pool_dev = pool_dev;
2540
2541         if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
2542                 ti->error = "Invalid device id";
2543                 r = -EINVAL;
2544                 goto bad_common;
2545         }
2546
2547         pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
2548         if (!pool_md) {
2549                 ti->error = "Couldn't get pool mapped device";
2550                 r = -EINVAL;
2551                 goto bad_common;
2552         }
2553
2554         tc->pool = __pool_table_lookup(pool_md);
2555         if (!tc->pool) {
2556                 ti->error = "Couldn't find pool object";
2557                 r = -EINVAL;
2558                 goto bad_pool_lookup;
2559         }
2560         __pool_inc(tc->pool);
2561
2562         if (get_pool_mode(tc->pool) == PM_FAIL) {
2563                 ti->error = "Couldn't open thin device, Pool is in fail mode";
2564                 goto bad_thin_open;
2565         }
2566
2567         r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
2568         if (r) {
2569                 ti->error = "Couldn't open thin internal device";
2570                 goto bad_thin_open;
2571         }
2572
2573         r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
2574         if (r)
2575                 goto bad_thin_open;
2576
2577         ti->num_flush_requests = 1;
2578         ti->flush_supported = true;
2579
2580         /* In case the pool supports discards, pass them on. */
2581         if (tc->pool->pf.discard_enabled) {
2582                 ti->discards_supported = true;
2583                 ti->num_discard_requests = 1;
2584                 ti->discard_zeroes_data_unsupported = true;
2585                 /* Discard requests must be split on a block boundary */
2586                 ti->split_discard_requests = true;
2587         }
2588
2589         dm_put(pool_md);
2590
2591         mutex_unlock(&dm_thin_pool_table.mutex);
2592
2593         return 0;
2594
2595 bad_thin_open:
2596         __pool_dec(tc->pool);
2597 bad_pool_lookup:
2598         dm_put(pool_md);
2599 bad_common:
2600         dm_put_device(ti, tc->pool_dev);
2601 bad_pool_dev:
2602         if (tc->origin_dev)
2603                 dm_put_device(ti, tc->origin_dev);
2604 bad_origin_dev:
2605         kfree(tc);
2606 out_unlock:
2607         mutex_unlock(&dm_thin_pool_table.mutex);
2608
2609         return r;
2610 }
2611
2612 static int thin_map(struct dm_target *ti, struct bio *bio,
2613                     union map_info *map_context)
2614 {
2615         bio->bi_sector = dm_target_offset(ti, bio->bi_sector);
2616
2617         return thin_bio_map(ti, bio, map_context);
2618 }
2619
2620 static int thin_endio(struct dm_target *ti,
2621                       struct bio *bio, int err,
2622                       union map_info *map_context)
2623 {
2624         unsigned long flags;
2625         struct dm_thin_endio_hook *h = map_context->ptr;
2626         struct list_head work;
2627         struct dm_thin_new_mapping *m, *tmp;
2628         struct pool *pool = h->tc->pool;
2629
2630         if (h->shared_read_entry) {
2631                 INIT_LIST_HEAD(&work);
2632                 dm_deferred_entry_dec(h->shared_read_entry, &work);
2633
2634                 spin_lock_irqsave(&pool->lock, flags);
2635                 list_for_each_entry_safe(m, tmp, &work, list) {
2636                         list_del(&m->list);
2637                         m->quiesced = 1;
2638                         __maybe_add_mapping(m);
2639                 }
2640                 spin_unlock_irqrestore(&pool->lock, flags);
2641         }
2642
2643         if (h->all_io_entry) {
2644                 INIT_LIST_HEAD(&work);
2645                 dm_deferred_entry_dec(h->all_io_entry, &work);
2646                 spin_lock_irqsave(&pool->lock, flags);
2647                 list_for_each_entry_safe(m, tmp, &work, list)
2648                         list_add(&m->list, &pool->prepared_discards);
2649                 spin_unlock_irqrestore(&pool->lock, flags);
2650         }
2651
2652         mempool_free(h, pool->endio_hook_pool);
2653
2654         return 0;
2655 }
2656
2657 static void thin_postsuspend(struct dm_target *ti)
2658 {
2659         if (dm_noflush_suspending(ti))
2660                 requeue_io((struct thin_c *)ti->private);
2661 }
2662
2663 /*
2664  * <nr mapped sectors> <highest mapped sector>
2665  */
2666 static int thin_status(struct dm_target *ti, status_type_t type,
2667                        unsigned status_flags, char *result, unsigned maxlen)
2668 {
2669         int r;
2670         ssize_t sz = 0;
2671         dm_block_t mapped, highest;
2672         char buf[BDEVNAME_SIZE];
2673         struct thin_c *tc = ti->private;
2674
2675         if (get_pool_mode(tc->pool) == PM_FAIL) {
2676                 DMEMIT("Fail");
2677                 return 0;
2678         }
2679
2680         if (!tc->td)
2681                 DMEMIT("-");
2682         else {
2683                 switch (type) {
2684                 case STATUSTYPE_INFO:
2685                         r = dm_thin_get_mapped_count(tc->td, &mapped);
2686                         if (r)
2687                                 return r;
2688
2689                         r = dm_thin_get_highest_mapped_block(tc->td, &highest);
2690                         if (r < 0)
2691                                 return r;
2692
2693                         DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
2694                         if (r)
2695                                 DMEMIT("%llu", ((highest + 1) *
2696                                                 tc->pool->sectors_per_block) - 1);
2697                         else
2698                                 DMEMIT("-");
2699                         break;
2700
2701                 case STATUSTYPE_TABLE:
2702                         DMEMIT("%s %lu",
2703                                format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
2704                                (unsigned long) tc->dev_id);
2705                         if (tc->origin_dev)
2706                                 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
2707                         break;
2708                 }
2709         }
2710
2711         return 0;
2712 }
2713
2714 static int thin_iterate_devices(struct dm_target *ti,
2715                                 iterate_devices_callout_fn fn, void *data)
2716 {
2717         sector_t blocks;
2718         struct thin_c *tc = ti->private;
2719         struct pool *pool = tc->pool;
2720
2721         /*
2722          * We can't call dm_pool_get_data_dev_size() since that blocks.  So
2723          * we follow a more convoluted path through to the pool's target.
2724          */
2725         if (!pool->ti)
2726                 return 0;       /* nothing is bound */
2727
2728         blocks = pool->ti->len;
2729         (void) sector_div(blocks, pool->sectors_per_block);
2730         if (blocks)
2731                 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
2732
2733         return 0;
2734 }
2735
2736 /*
2737  * A thin device always inherits its queue limits from its pool.
2738  */
2739 static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
2740 {
2741         struct thin_c *tc = ti->private;
2742
2743         *limits = bdev_get_queue(tc->pool_dev->bdev)->limits;
2744 }
2745
2746 static struct target_type thin_target = {
2747         .name = "thin",
2748         .version = {1, 5, 0},
2749         .module = THIS_MODULE,
2750         .ctr = thin_ctr,
2751         .dtr = thin_dtr,
2752         .map = thin_map,
2753         .end_io = thin_endio,
2754         .postsuspend = thin_postsuspend,
2755         .status = thin_status,
2756         .iterate_devices = thin_iterate_devices,
2757         .io_hints = thin_io_hints,
2758 };
2759
2760 /*----------------------------------------------------------------*/
2761
2762 static int __init dm_thin_init(void)
2763 {
2764         int r;
2765
2766         pool_table_init();
2767
2768         r = dm_register_target(&thin_target);
2769         if (r)
2770                 return r;
2771
2772         r = dm_register_target(&pool_target);
2773         if (r)
2774                 goto bad_pool_target;
2775
2776         r = -ENOMEM;
2777
2778         _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
2779         if (!_new_mapping_cache)
2780                 goto bad_new_mapping_cache;
2781
2782         _endio_hook_cache = KMEM_CACHE(dm_thin_endio_hook, 0);
2783         if (!_endio_hook_cache)
2784                 goto bad_endio_hook_cache;
2785
2786         return 0;
2787
2788 bad_endio_hook_cache:
2789         kmem_cache_destroy(_new_mapping_cache);
2790 bad_new_mapping_cache:
2791         dm_unregister_target(&pool_target);
2792 bad_pool_target:
2793         dm_unregister_target(&thin_target);
2794
2795         return r;
2796 }
2797
2798 static void dm_thin_exit(void)
2799 {
2800         dm_unregister_target(&thin_target);
2801         dm_unregister_target(&pool_target);
2802
2803         kmem_cache_destroy(_new_mapping_cache);
2804         kmem_cache_destroy(_endio_hook_cache);
2805 }
2806
2807 module_init(dm_thin_init);
2808 module_exit(dm_thin_exit);
2809
2810 MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
2811 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2812 MODULE_LICENSE("GPL");