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 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
  30                 "A percentage of time allocated for copy on write");
  31
  32 /*
  33  * The block size of the device holding pool data must be
  34  * between 64KB and 1GB.
  35  */
  36 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
  37 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
  38
  39 /*
  40  * Device id is restricted to 24 bits.
  41  */
  42 #define MAX_DEV_ID ((1 << 24) - 1)
  43
  44 /*
  45  * How do we handle breaking sharing of data blocks?
  46  * =================================================
  47  *
  48  * We use a standard copy-on-write btree to store the mappings for the
  49  * devices (note I'm talking about copy-on-write of the metadata here, not
  50  * the data).  When you take an internal snapshot you clone the root node
  51  * of the origin btree.  After this there is no concept of an origin or a
  52  * snapshot.  They are just two device trees that happen to point to the
  53  * same data blocks.
  54  *
  55  * When we get a write in we decide if it's to a shared data block using
  56  * some timestamp magic.  If it is, we have to break sharing.
  57  *
  58  * Let's say we write to a shared block in what was the origin.  The
  59  * steps are:
  60  *
  61  * i) plug io further to this physical block. (see bio_prison code).
  62  *
  63  * ii) quiesce any read io to that shared data block.  Obviously
  64  * including all devices that share this block.  (see dm_deferred_set code)
  65  *
  66  * iii) copy the data block to a newly allocate block.  This step can be
  67  * missed out if the io covers the block. (schedule_copy).
  68  *
  69  * iv) insert the new mapping into the origin's btree
  70  * (process_prepared_mapping).  This act of inserting breaks some
  71  * sharing of btree nodes between the two devices.  Breaking sharing only
  72  * effects the btree of that specific device.  Btrees for the other
  73  * devices that share the block never change.  The btree for the origin
  74  * device as it was after the last commit is untouched, ie. we're using
  75  * persistent data structures in the functional programming sense.
  76  *
  77  * v) unplug io to this physical block, including the io that triggered
  78  * the breaking of sharing.
  79  *
  80  * Steps (ii) and (iii) occur in parallel.
  81  *
  82  * The metadata _doesn't_ need to be committed before the io continues.  We
  83  * get away with this because the io is always written to a _new_ block.
  84  * If there's a crash, then:
  85  *
  86  * - The origin mapping will point to the old origin block (the shared
  87  * one).  This will contain the data as it was before the io that triggered
  88  * the breaking of sharing came in.
  89  *
  90  * - The snap mapping still points to the old block.  As it would after
  91  * the commit.
  92  *
  93  * The downside of this scheme is the timestamp magic isn't perfect, and
  94  * will continue to think that data block in the snapshot device is shared
  95  * even after the write to the origin has broken sharing.  I suspect data
  96  * blocks will typically be shared by many different devices, so we're
  97  * breaking sharing n + 1 times, rather than n, where n is the number of
  98  * devices that reference this data block.  At the moment I think the
  99  * benefits far, far outweigh the disadvantages.
 100  */
 101
 102 /*----------------------------------------------------------------*/
 103
 104 /*
 105  * Key building.
 106  */
 107 static void build_data_key(struct dm_thin_device *td,
 108                            dm_block_t b, struct dm_cell_key *key)
 109 {
 110         key->virtual = 0;
 111         key->dev = dm_thin_dev_id(td);
 112         key->block = b;
 113 }
 114
 115 static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
 116                               struct dm_cell_key *key)
 117 {
 118         key->virtual = 1;
 119         key->dev = dm_thin_dev_id(td);
 120         key->block = b;
 121 }
 122
 123 /*----------------------------------------------------------------*/
 124
 125 /*
 126  * A pool device ties together a metadata device and a data device.  It
 127  * also provides the interface for creating and destroying internal
 128  * devices.
 129  */
 130 struct dm_thin_new_mapping;
 131
 132 /*
 133  * The pool runs in 3 modes.  Ordered in degraded order for comparisons.
 134  */
 135 enum pool_mode {
 136         PM_WRITE,               /* metadata may be changed */
 137         PM_READ_ONLY,           /* metadata may not be changed */
 138         PM_FAIL,                /* all I/O fails */
 139 };
 140
 141 struct pool_features {
 142         enum pool_mode mode;
 143
 144         bool zero_new_blocks:1;
 145         bool discard_enabled:1;
 146         bool discard_passdown:1;
 147 };
 148
 149 struct thin_c;
 150 typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
 151 typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
 152
 153 struct pool {
 154         struct list_head list;
 155         struct dm_target *ti;   /* Only set if a pool target is bound */
 156
 157         struct mapped_device *pool_md;
 158         struct block_device *md_dev;
 159         struct dm_pool_metadata *pmd;
 160
 161         dm_block_t low_water_blocks;
 162         uint32_t sectors_per_block;
 163         int sectors_per_block_shift;
 164
 165         struct pool_features pf;
 166         unsigned low_water_triggered:1; /* A dm event has been sent */
 167         unsigned no_free_space:1;       /* A -ENOSPC warning has been issued */
 168
 169         struct dm_bio_prison *prison;
 170         struct dm_kcopyd_client *copier;
 171
 172         struct workqueue_struct *wq;
 173         struct work_struct worker;
 174         struct delayed_work waker;
 175
 176         unsigned long last_commit_jiffies;
 177         unsigned ref_count;
 178
 179         spinlock_t lock;
 180         struct bio_list deferred_bios;
 181         struct bio_list deferred_flush_bios;
 182         struct list_head prepared_mappings;
 183         struct list_head prepared_discards;
 184
 185         struct bio_list retry_on_resume_list;
 186
 187         struct dm_deferred_set *shared_read_ds;
 188         struct dm_deferred_set *all_io_ds;
 189
 190         struct dm_thin_new_mapping *next_mapping;
 191         mempool_t *mapping_pool;
 192
 193         process_bio_fn process_bio;
 194         process_bio_fn process_discard;
 195
 196         process_mapping_fn process_prepared_mapping;
 197         process_mapping_fn process_prepared_discard;
 198 };
 199
 200 static enum pool_mode get_pool_mode(struct pool *pool);
 201 static void set_pool_mode(struct pool *pool, enum pool_mode mode);
 202
 203 /*
 204  * Target context for a pool.
 205  */
 206 struct pool_c {
 207         struct dm_target *ti;
 208         struct pool *pool;
 209         struct dm_dev *data_dev;
 210         struct dm_dev *metadata_dev;
 211         struct dm_target_callbacks callbacks;
 212
 213         dm_block_t low_water_blocks;
 214         struct pool_features requested_pf; /* Features requested during table load */
 215         struct pool_features adjusted_pf;  /* Features used after adjusting for constituent devices */
 216 };
 217
 218 /*
 219  * Target context for a thin.
 220  */
 221 struct thin_c {
 222         struct dm_dev *pool_dev;
 223         struct dm_dev *origin_dev;
 224         dm_thin_id dev_id;
 225
 226         struct pool *pool;
 227         struct dm_thin_device *td;
 228 };
 229
 230 /*----------------------------------------------------------------*/
 231
 232 /*
 233  * wake_worker() is used when new work is queued and when pool_resume is
 234  * ready to continue deferred IO processing.
 235  */
 236 static void wake_worker(struct pool *pool)
 237 {
 238         queue_work(pool->wq, &pool->worker);
 239 }
 240
 241 /*----------------------------------------------------------------*/
 242
 243 static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
 244                       struct dm_bio_prison_cell **cell_result)
 245 {
 246         int r;
 247         struct dm_bio_prison_cell *cell_prealloc;
 248
 249         /*
 250          * Allocate a cell from the prison's mempool.
 251          * This might block but it can't fail.
 252          */
 253         cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
 254
 255         r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
 256         if (r)
 257                 /*
 258                  * We reused an old cell; we can get rid of
 259                  * the new one.
 260                  */
 261                 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
 262
 263         return r;
 264 }
 265
 266 static void cell_release(struct pool *pool,
 267                          struct dm_bio_prison_cell *cell,
 268                          struct bio_list *bios)
 269 {
 270         dm_cell_release(pool->prison, cell, bios);
 271         dm_bio_prison_free_cell(pool->prison, cell);
 272 }
 273
 274 static void cell_release_no_holder(struct pool *pool,
 275                                    struct dm_bio_prison_cell *cell,
 276                                    struct bio_list *bios)
 277 {
 278         dm_cell_release_no_holder(pool->prison, cell, bios);
 279         dm_bio_prison_free_cell(pool->prison, cell);
 280 }
 281
 282 static void cell_defer_no_holder_no_free(struct thin_c *tc,
 283                                          struct dm_bio_prison_cell *cell)
 284 {
 285         struct pool *pool = tc->pool;
 286         unsigned long flags;
 287
 288         spin_lock_irqsave(&pool->lock, flags);
 289         dm_cell_release_no_holder(pool->prison, cell, &pool->deferred_bios);
 290         spin_unlock_irqrestore(&pool->lock, flags);
 291
 292         wake_worker(pool);
 293 }
 294
 295 static void cell_error(struct pool *pool,
 296                        struct dm_bio_prison_cell *cell)
 297 {
 298         dm_cell_error(pool->prison, cell);
 299         dm_bio_prison_free_cell(pool->prison, cell);
 300 }
 301
 302 /*----------------------------------------------------------------*/
 303
 304 /*
 305  * A global list of pools that uses a struct mapped_device as a key.
 306  */
 307 static struct dm_thin_pool_table {
 308         struct mutex mutex;
 309         struct list_head pools;
 310 } dm_thin_pool_table;
 311
 312 static void pool_table_init(void)
 313 {
 314         mutex_init(&dm_thin_pool_table.mutex);
 315         INIT_LIST_HEAD(&dm_thin_pool_table.pools);
 316 }
 317
 318 static void __pool_table_insert(struct pool *pool)
 319 {
 320         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
 321         list_add(&pool->list, &dm_thin_pool_table.pools);
 322 }
 323
 324 static void __pool_table_remove(struct pool *pool)
 325 {
 326         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
 327         list_del(&pool->list);
 328 }
 329
 330 static struct pool *__pool_table_lookup(struct mapped_device *md)
 331 {
 332         struct pool *pool = NULL, *tmp;
 333
 334         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
 335
 336         list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
 337                 if (tmp->pool_md == md) {
 338                         pool = tmp;
 339                         break;
 340                 }
 341         }
 342
 343         return pool;
 344 }
 345
 346 static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
 347 {
 348         struct pool *pool = NULL, *tmp;
 349
 350         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
 351
 352         list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
 353                 if (tmp->md_dev == md_dev) {
 354                         pool = tmp;
 355                         break;
 356                 }
 357         }
 358
 359         return pool;
 360 }
 361
 362 /*----------------------------------------------------------------*/
 363
 364 struct dm_thin_endio_hook {
 365         struct thin_c *tc;
 366         struct dm_deferred_entry *shared_read_entry;
 367         struct dm_deferred_entry *all_io_entry;
 368         struct dm_thin_new_mapping *overwrite_mapping;
 369 };
 370
 371 static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
 372 {
 373         struct bio *bio;
 374         struct bio_list bios;
 375
 376         bio_list_init(&bios);
 377         bio_list_merge(&bios, master);
 378         bio_list_init(master);
 379
 380         while ((bio = bio_list_pop(&bios))) {
 381                 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 382
 383                 if (h->tc == tc)
 384                         bio_endio(bio, DM_ENDIO_REQUEUE);
 385                 else
 386                         bio_list_add(master, bio);
 387         }
 388 }
 389
 390 static void requeue_io(struct thin_c *tc)
 391 {
 392         struct pool *pool = tc->pool;
 393         unsigned long flags;
 394
 395         spin_lock_irqsave(&pool->lock, flags);
 396         __requeue_bio_list(tc, &pool->deferred_bios);
 397         __requeue_bio_list(tc, &pool->retry_on_resume_list);
 398         spin_unlock_irqrestore(&pool->lock, flags);
 399 }
 400
 401 /*
 402  * This section of code contains the logic for processing a thin device's IO.
 403  * Much of the code depends on pool object resources (lists, workqueues, etc)
 404  * but most is exclusively called from the thin target rather than the thin-pool
 405  * target.
 406  */
 407
 408 static bool block_size_is_power_of_two(struct pool *pool)
 409 {
 410         return pool->sectors_per_block_shift >= 0;
 411 }
 412
 413 static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
 414 {
 415         struct pool *pool = tc->pool;
 416         sector_t block_nr = bio->bi_sector;
 417
 418         if (block_size_is_power_of_two(pool))
 419                 block_nr >>= pool->sectors_per_block_shift;
 420         else
 421                 (void) sector_div(block_nr, pool->sectors_per_block);
 422
 423         return block_nr;
 424 }
 425
 426 static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
 427 {
 428         struct pool *pool = tc->pool;
 429         sector_t bi_sector = bio->bi_sector;
 430
 431         bio->bi_bdev = tc->pool_dev->bdev;
 432         if (block_size_is_power_of_two(pool))
 433                 bio->bi_sector = (block << pool->sectors_per_block_shift) |
 434                                 (bi_sector & (pool->sectors_per_block - 1));
 435         else
 436                 bio->bi_sector = (block * pool->sectors_per_block) +
 437                                  sector_div(bi_sector, pool->sectors_per_block);
 438 }
 439
 440 static void remap_to_origin(struct thin_c *tc, struct bio *bio)
 441 {
 442         bio->bi_bdev = tc->origin_dev->bdev;
 443 }
 444
 445 static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
 446 {
 447         return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
 448                 dm_thin_changed_this_transaction(tc->td);
 449 }
 450
 451 static void inc_all_io_entry(struct pool *pool, struct bio *bio)
 452 {
 453         struct dm_thin_endio_hook *h;
 454
 455         if (bio->bi_rw & REQ_DISCARD)
 456                 return;
 457
 458         h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 459         h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
 460 }
 461
 462 static void issue(struct thin_c *tc, struct bio *bio)
 463 {
 464         struct pool *pool = tc->pool;
 465         unsigned long flags;
 466
 467         if (!bio_triggers_commit(tc, bio)) {
 468                 generic_make_request(bio);
 469                 return;
 470         }
 471
 472         /*
 473          * Complete bio with an error if earlier I/O caused changes to
 474          * the metadata that can't be committed e.g, due to I/O errors
 475          * on the metadata device.
 476          */
 477         if (dm_thin_aborted_changes(tc->td)) {
 478                 bio_io_error(bio);
 479                 return;
 480         }
 481
 482         /*
 483          * Batch together any bios that trigger commits and then issue a
 484          * single commit for them in process_deferred_bios().
 485          */
 486         spin_lock_irqsave(&pool->lock, flags);
 487         bio_list_add(&pool->deferred_flush_bios, bio);
 488         spin_unlock_irqrestore(&pool->lock, flags);
 489 }
 490
 491 static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
 492 {
 493         remap_to_origin(tc, bio);
 494         issue(tc, bio);
 495 }
 496
 497 static void remap_and_issue(struct thin_c *tc, struct bio *bio,
 498                             dm_block_t block)
 499 {
 500         remap(tc, bio, block);
 501         issue(tc, bio);
 502 }
 503
 504 /*----------------------------------------------------------------*/
 505
 506 /*
 507  * Bio endio functions.
 508  */
 509 struct dm_thin_new_mapping {
 510         struct list_head list;
 511
 512         unsigned quiesced:1;
 513         unsigned prepared:1;
 514         unsigned pass_discard:1;
 515
 516         struct thin_c *tc;
 517         dm_block_t virt_block;
 518         dm_block_t data_block;
 519         struct dm_bio_prison_cell *cell, *cell2;
 520         int err;
 521
 522         /*
 523          * If the bio covers the whole area of a block then we can avoid
 524          * zeroing or copying.  Instead this bio is hooked.  The bio will
 525          * still be in the cell, so care has to be taken to avoid issuing
 526          * the bio twice.
 527          */
 528         struct bio *bio;
 529         bio_end_io_t *saved_bi_end_io;
 530 };
 531
 532 static void __maybe_add_mapping(struct dm_thin_new_mapping *m)
 533 {
 534         struct pool *pool = m->tc->pool;
 535
 536         if (m->quiesced && m->prepared) {
 537                 list_add(&m->list, &pool->prepared_mappings);
 538                 wake_worker(pool);
 539         }
 540 }
 541
 542 static void copy_complete(int read_err, unsigned long write_err, void *context)
 543 {
 544         unsigned long flags;
 545         struct dm_thin_new_mapping *m = context;
 546         struct pool *pool = m->tc->pool;
 547
 548         m->err = read_err || write_err ? -EIO : 0;
 549
 550         spin_lock_irqsave(&pool->lock, flags);
 551         m->prepared = 1;
 552         __maybe_add_mapping(m);
 553         spin_unlock_irqrestore(&pool->lock, flags);
 554 }
 555
 556 static void overwrite_endio(struct bio *bio, int err)
 557 {
 558         unsigned long flags;
 559         struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 560         struct dm_thin_new_mapping *m = h->overwrite_mapping;
 561         struct pool *pool = m->tc->pool;
 562
 563         m->err = err;
 564
 565         spin_lock_irqsave(&pool->lock, flags);
 566         m->prepared = 1;
 567         __maybe_add_mapping(m);
 568         spin_unlock_irqrestore(&pool->lock, flags);
 569 }
 570
 571 /*----------------------------------------------------------------*/
 572
 573 /*
 574  * Workqueue.
 575  */
 576
 577 /*
 578  * Prepared mapping jobs.
 579  */
 580
 581 /*
 582  * This sends the bios in the cell back to the deferred_bios list.
 583  */
 584 static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell)
 585 {
 586         struct pool *pool = tc->pool;
 587         unsigned long flags;
 588
 589         spin_lock_irqsave(&pool->lock, flags);
 590         cell_release(pool, cell, &pool->deferred_bios);
 591         spin_unlock_irqrestore(&tc->pool->lock, flags);
 592
 593         wake_worker(pool);
 594 }
 595
 596 /*
 597  * Same as cell_defer above, except it omits the original holder of the cell.
 598  */
 599 static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
 600 {
 601         struct pool *pool = tc->pool;
 602         unsigned long flags;
 603
 604         spin_lock_irqsave(&pool->lock, flags);
 605         cell_release_no_holder(pool, cell, &pool->deferred_bios);
 606         spin_unlock_irqrestore(&pool->lock, flags);
 607
 608         wake_worker(pool);
 609 }
 610
 611 static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
 612 {
 613         if (m->bio)
 614                 m->bio->bi_end_io = m->saved_bi_end_io;
 615         cell_error(m->tc->pool, m->cell);
 616         list_del(&m->list);
 617         mempool_free(m, m->tc->pool->mapping_pool);
 618 }
 619
 620 static void process_prepared_mapping(struct dm_thin_new_mapping *m)
 621 {
 622         struct thin_c *tc = m->tc;
 623         struct pool *pool = tc->pool;
 624         struct bio *bio;
 625         int r;
 626
 627         bio = m->bio;
 628         if (bio)
 629                 bio->bi_end_io = m->saved_bi_end_io;
 630
 631         if (m->err) {
 632                 cell_error(pool, m->cell);
 633                 goto out;
 634         }
 635
 636         /*
 637          * Commit the prepared block into the mapping btree.
 638          * Any I/O for this block arriving after this point will get
 639          * remapped to it directly.
 640          */
 641         r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
 642         if (r) {
 643                 DMERR_LIMIT("dm_thin_insert_block() failed");
 644                 cell_error(pool, m->cell);
 645                 goto out;
 646         }
 647
 648         /*
 649          * Release any bios held while the block was being provisioned.
 650          * If we are processing a write bio that completely covers the block,
 651          * we already processed it so can ignore it now when processing
 652          * the bios in the cell.
 653          */
 654         if (bio) {
 655                 cell_defer_no_holder(tc, m->cell);
 656                 bio_endio(bio, 0);
 657         } else
 658                 cell_defer(tc, m->cell);
 659
 660 out:
 661         list_del(&m->list);
 662         mempool_free(m, pool->mapping_pool);
 663 }
 664
 665 static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
 666 {
 667         struct thin_c *tc = m->tc;
 668
 669         bio_io_error(m->bio);
 670         cell_defer_no_holder(tc, m->cell);
 671         cell_defer_no_holder(tc, m->cell2);
 672         mempool_free(m, tc->pool->mapping_pool);
 673 }
 674
 675 static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
 676 {
 677         struct thin_c *tc = m->tc;
 678
 679         inc_all_io_entry(tc->pool, m->bio);
 680         cell_defer_no_holder(tc, m->cell);
 681         cell_defer_no_holder(tc, m->cell2);
 682
 683         if (m->pass_discard)
 684                 remap_and_issue(tc, m->bio, m->data_block);
 685         else
 686                 bio_endio(m->bio, 0);
 687
 688         mempool_free(m, tc->pool->mapping_pool);
 689 }
 690
 691 static void process_prepared_discard(struct dm_thin_new_mapping *m)
 692 {
 693         int r;
 694         struct thin_c *tc = m->tc;
 695
 696         r = dm_thin_remove_block(tc->td, m->virt_block);
 697         if (r)
 698                 DMERR_LIMIT("dm_thin_remove_block() failed");
 699
 700         process_prepared_discard_passdown(m);
 701 }
 702
 703 static void process_prepared(struct pool *pool, struct list_head *head,
 704                              process_mapping_fn *fn)
 705 {
 706         unsigned long flags;
 707         struct list_head maps;
 708         struct dm_thin_new_mapping *m, *tmp;
 709
 710         INIT_LIST_HEAD(&maps);
 711         spin_lock_irqsave(&pool->lock, flags);
 712         list_splice_init(head, &maps);
 713         spin_unlock_irqrestore(&pool->lock, flags);
 714
 715         list_for_each_entry_safe(m, tmp, &maps, list)
 716                 (*fn)(m);
 717 }
 718
 719 /*
 720  * Deferred bio jobs.
 721  */
 722 static int io_overlaps_block(struct pool *pool, struct bio *bio)
 723 {
 724         return bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT);
 725 }
 726
 727 static int io_overwrites_block(struct pool *pool, struct bio *bio)
 728 {
 729         return (bio_data_dir(bio) == WRITE) &&
 730                 io_overlaps_block(pool, bio);
 731 }
 732
 733 static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
 734                                bio_end_io_t *fn)
 735 {
 736         *save = bio->bi_end_io;
 737         bio->bi_end_io = fn;
 738 }
 739
 740 static int ensure_next_mapping(struct pool *pool)
 741 {
 742         if (pool->next_mapping)
 743                 return 0;
 744
 745         pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
 746
 747         return pool->next_mapping ? 0 : -ENOMEM;
 748 }
 749
 750 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
 751 {
 752         struct dm_thin_new_mapping *r = pool->next_mapping;
 753
 754         BUG_ON(!pool->next_mapping);
 755
 756         pool->next_mapping = NULL;
 757
 758         return r;
 759 }
 760
 761 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
 762                           struct dm_dev *origin, dm_block_t data_origin,
 763                           dm_block_t data_dest,
 764                           struct dm_bio_prison_cell *cell, struct bio *bio)
 765 {
 766         int r;
 767         struct pool *pool = tc->pool;
 768         struct dm_thin_new_mapping *m = get_next_mapping(pool);
 769
 770         INIT_LIST_HEAD(&m->list);
 771         m->quiesced = 0;
 772         m->prepared = 0;
 773         m->tc = tc;
 774         m->virt_block = virt_block;
 775         m->data_block = data_dest;
 776         m->cell = cell;
 777         m->err = 0;
 778         m->bio = NULL;
 779
 780         if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
 781                 m->quiesced = 1;
 782
 783         /*
 784          * IO to pool_dev remaps to the pool target's data_dev.
 785          *
 786          * If the whole block of data is being overwritten, we can issue the
 787          * bio immediately. Otherwise we use kcopyd to clone the data first.
 788          */
 789         if (io_overwrites_block(pool, bio)) {
 790                 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 791
 792                 h->overwrite_mapping = m;
 793                 m->bio = bio;
 794                 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
 795                 inc_all_io_entry(pool, bio);
 796                 remap_and_issue(tc, bio, data_dest);
 797         } else {
 798                 struct dm_io_region from, to;
 799
 800                 from.bdev = origin->bdev;
 801                 from.sector = data_origin * pool->sectors_per_block;
 802                 from.count = pool->sectors_per_block;
 803
 804                 to.bdev = tc->pool_dev->bdev;
 805                 to.sector = data_dest * pool->sectors_per_block;
 806                 to.count = pool->sectors_per_block;
 807
 808                 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
 809                                    0, copy_complete, m);
 810                 if (r < 0) {
 811                         mempool_free(m, pool->mapping_pool);
 812                         DMERR_LIMIT("dm_kcopyd_copy() failed");
 813                         cell_error(pool, cell);
 814                 }
 815         }
 816 }
 817
 818 static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
 819                                    dm_block_t data_origin, dm_block_t data_dest,
 820                                    struct dm_bio_prison_cell *cell, struct bio *bio)
 821 {
 822         schedule_copy(tc, virt_block, tc->pool_dev,
 823                       data_origin, data_dest, cell, bio);
 824 }
 825
 826 static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
 827                                    dm_block_t data_dest,
 828                                    struct dm_bio_prison_cell *cell, struct bio *bio)
 829 {
 830         schedule_copy(tc, virt_block, tc->origin_dev,
 831                       virt_block, data_dest, cell, bio);
 832 }
 833
 834 static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
 835                           dm_block_t data_block, struct dm_bio_prison_cell *cell,
 836                           struct bio *bio)
 837 {
 838         struct pool *pool = tc->pool;
 839         struct dm_thin_new_mapping *m = get_next_mapping(pool);
 840
 841         INIT_LIST_HEAD(&m->list);
 842         m->quiesced = 1;
 843         m->prepared = 0;
 844         m->tc = tc;
 845         m->virt_block = virt_block;
 846         m->data_block = data_block;
 847         m->cell = cell;
 848         m->err = 0;
 849         m->bio = NULL;
 850
 851         /*
 852          * If the whole block of data is being overwritten or we are not
 853          * zeroing pre-existing data, we can issue the bio immediately.
 854          * Otherwise we use kcopyd to zero the data first.
 855          */
 856         if (!pool->pf.zero_new_blocks)
 857                 process_prepared_mapping(m);
 858
 859         else if (io_overwrites_block(pool, bio)) {
 860                 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 861
 862                 h->overwrite_mapping = m;
 863                 m->bio = bio;
 864                 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
 865                 inc_all_io_entry(pool, bio);
 866                 remap_and_issue(tc, bio, data_block);
 867         } else {
 868                 int r;
 869                 struct dm_io_region to;
 870
 871                 to.bdev = tc->pool_dev->bdev;
 872                 to.sector = data_block * pool->sectors_per_block;
 873                 to.count = pool->sectors_per_block;
 874
 875                 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
 876                 if (r < 0) {
 877                         mempool_free(m, pool->mapping_pool);
 878                         DMERR_LIMIT("dm_kcopyd_zero() failed");
 879                         cell_error(pool, cell);
 880                 }
 881         }
 882 }
 883
 884 static int commit(struct pool *pool)
 885 {
 886         int r;
 887
 888         r = dm_pool_commit_metadata(pool->pmd);
 889         if (r)
 890                 DMERR_LIMIT("commit failed: error = %d", r);
 891
 892         return r;
 893 }
 894
 895 /*
 896  * A non-zero return indicates read_only or fail_io mode.
 897  * Many callers don't care about the return value.
 898  */
 899 static int commit_or_fallback(struct pool *pool)
 900 {
 901         int r;
 902
 903         if (get_pool_mode(pool) != PM_WRITE)
 904                 return -EINVAL;
 905
 906         r = commit(pool);
 907         if (r)
 908                 set_pool_mode(pool, PM_READ_ONLY);
 909
 910         return r;
 911 }
 912
 913 static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
 914 {
 915         int r;
 916         dm_block_t free_blocks;
 917         unsigned long flags;
 918         struct pool *pool = tc->pool;
 919
 920         r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
 921         if (r)
 922                 return r;
 923
 924         if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
 925                 DMWARN("%s: reached low water mark, sending event.",
 926                        dm_device_name(pool->pool_md));
 927                 spin_lock_irqsave(&pool->lock, flags);
 928                 pool->low_water_triggered = 1;
 929                 spin_unlock_irqrestore(&pool->lock, flags);
 930                 dm_table_event(pool->ti->table);
 931         }
 932
 933         if (!free_blocks) {
 934                 if (pool->no_free_space)
 935                         return -ENOSPC;
 936                 else {
 937                         /*
 938                          * Try to commit to see if that will free up some
 939                          * more space.
 940                          */
 941                         (void) commit_or_fallback(pool);
 942
 943                         r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
 944                         if (r)
 945                                 return r;
 946
 947                         /*
 948                          * If we still have no space we set a flag to avoid
 949                          * doing all this checking and return -ENOSPC.
 950                          */
 951                         if (!free_blocks) {
 952                                 DMWARN("%s: no free space available.",
 953                                        dm_device_name(pool->pool_md));
 954                                 spin_lock_irqsave(&pool->lock, flags);
 955                                 pool->no_free_space = 1;
 956                                 spin_unlock_irqrestore(&pool->lock, flags);
 957                                 return -ENOSPC;
 958                         }
 959                 }
 960         }
 961
 962         r = dm_pool_alloc_data_block(pool->pmd, result);
 963         if (r)
 964                 return r;
 965
 966         return 0;
 967 }
 968
 969 /*
 970  * If we have run out of space, queue bios until the device is
 971  * resumed, presumably after having been reloaded with more space.
 972  */
 973 static void retry_on_resume(struct bio *bio)
 974 {
 975         struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
 976         struct thin_c *tc = h->tc;
 977         struct pool *pool = tc->pool;
 978         unsigned long flags;
 979
 980         spin_lock_irqsave(&pool->lock, flags);
 981         bio_list_add(&pool->retry_on_resume_list, bio);
 982         spin_unlock_irqrestore(&pool->lock, flags);
 983 }
 984
 985 static void no_space(struct pool *pool, struct dm_bio_prison_cell *cell)
 986 {
 987         struct bio *bio;
 988         struct bio_list bios;
 989
 990         bio_list_init(&bios);
 991         cell_release(pool, cell, &bios);
 992
 993         while ((bio = bio_list_pop(&bios)))
 994                 retry_on_resume(bio);
 995 }
 996
 997 static void process_discard(struct thin_c *tc, struct bio *bio)
 998 {
 999         int r;
1000         unsigned long flags;
1001         struct pool *pool = tc->pool;
1002         struct dm_bio_prison_cell *cell, *cell2;
1003         struct dm_cell_key key, key2;
1004         dm_block_t block = get_bio_block(tc, bio);
1005         struct dm_thin_lookup_result lookup_result;
1006         struct dm_thin_new_mapping *m;
1007
1008         build_virtual_key(tc->td, block, &key);
1009         if (bio_detain(tc->pool, &key, bio, &cell))
1010                 return;
1011
1012         r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1013         switch (r) {
1014         case 0:
1015                 /*
1016                  * Check nobody is fiddling with this pool block.  This can
1017                  * happen if someone's in the process of breaking sharing
1018                  * on this block.
1019                  */
1020                 build_data_key(tc->td, lookup_result.block, &key2);
1021                 if (bio_detain(tc->pool, &key2, bio, &cell2)) {
1022                         cell_defer_no_holder(tc, cell);
1023                         break;
1024                 }
1025
1026                 if (io_overlaps_block(pool, bio)) {
1027                         /*
1028                          * IO may still be going to the destination block.  We must
1029                          * quiesce before we can do the removal.
1030                          */
1031                         m = get_next_mapping(pool);
1032                         m->tc = tc;
1033                         m->pass_discard = (!lookup_result.shared) && pool->pf.discard_passdown;
1034                         m->virt_block = block;
1035                         m->data_block = lookup_result.block;
1036                         m->cell = cell;
1037                         m->cell2 = cell2;
1038                         m->err = 0;
1039                         m->bio = bio;
1040
1041                         if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
1042                                 spin_lock_irqsave(&pool->lock, flags);
1043                                 list_add(&m->list, &pool->prepared_discards);
1044                                 spin_unlock_irqrestore(&pool->lock, flags);
1045                                 wake_worker(pool);
1046                         }
1047                 } else {
1048                         inc_all_io_entry(pool, bio);
1049                         cell_defer_no_holder(tc, cell);
1050                         cell_defer_no_holder(tc, cell2);
1051
1052                         /*
1053                          * The DM core makes sure that the discard doesn't span
1054                          * a block boundary.  So we submit the discard of a
1055                          * partial block appropriately.
1056                          */
1057                         if ((!lookup_result.shared) && pool->pf.discard_passdown)
1058                                 remap_and_issue(tc, bio, lookup_result.block);
1059                         else
1060                                 bio_endio(bio, 0);
1061                 }
1062                 break;
1063
1064         case -ENODATA:
1065                 /*
1066                  * It isn't provisioned, just forget it.
1067                  */
1068                 cell_defer_no_holder(tc, cell);
1069                 bio_endio(bio, 0);
1070                 break;
1071
1072         default:
1073                 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1074                             __func__, r);
1075                 cell_defer_no_holder(tc, cell);
1076                 bio_io_error(bio);
1077                 break;
1078         }
1079 }
1080
1081 static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1082                           struct dm_cell_key *key,
1083                           struct dm_thin_lookup_result *lookup_result,
1084                           struct dm_bio_prison_cell *cell)
1085 {
1086         int r;
1087         dm_block_t data_block;
1088
1089         r = alloc_data_block(tc, &data_block);
1090         switch (r) {
1091         case 0:
1092                 schedule_internal_copy(tc, block, lookup_result->block,
1093                                        data_block, cell, bio);
1094                 break;
1095
1096         case -ENOSPC:
1097                 no_space(tc->pool, cell);
1098                 break;
1099
1100         default:
1101                 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1102                             __func__, r);
1103                 cell_error(tc->pool, cell);
1104                 break;
1105         }
1106 }
1107
1108 static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1109                                dm_block_t block,
1110                                struct dm_thin_lookup_result *lookup_result)
1111 {
1112         struct dm_bio_prison_cell *cell;
1113         struct pool *pool = tc->pool;
1114         struct dm_cell_key key;
1115
1116         /*
1117          * If cell is already occupied, then sharing is already in the process
1118          * of being broken so we have nothing further to do here.
1119          */
1120         build_data_key(tc->td, lookup_result->block, &key);
1121         if (bio_detain(pool, &key, bio, &cell))
1122                 return;
1123
1124         if (bio_data_dir(bio) == WRITE && bio->bi_size)
1125                 break_sharing(tc, bio, block, &key, lookup_result, cell);
1126         else {
1127                 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1128
1129                 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1130                 inc_all_io_entry(pool, bio);
1131                 cell_defer_no_holder(tc, cell);
1132
1133                 remap_and_issue(tc, bio, lookup_result->block);
1134         }
1135 }
1136
1137 static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1138                             struct dm_bio_prison_cell *cell)
1139 {
1140         int r;
1141         dm_block_t data_block;
1142         struct pool *pool = tc->pool;
1143
1144         /*
1145          * Remap empty bios (flushes) immediately, without provisioning.
1146          */
1147         if (!bio->bi_size) {
1148                 inc_all_io_entry(pool, bio);
1149                 cell_defer_no_holder(tc, cell);
1150
1151                 remap_and_issue(tc, bio, 0);
1152                 return;
1153         }
1154
1155         /*
1156          * Fill read bios with zeroes and complete them immediately.
1157          */
1158         if (bio_data_dir(bio) == READ) {
1159                 zero_fill_bio(bio);
1160                 cell_defer_no_holder(tc, cell);
1161                 bio_endio(bio, 0);
1162                 return;
1163         }
1164
1165         r = alloc_data_block(tc, &data_block);
1166         switch (r) {
1167         case 0:
1168                 if (tc->origin_dev)
1169                         schedule_external_copy(tc, block, data_block, cell, bio);
1170                 else
1171                         schedule_zero(tc, block, data_block, cell, bio);
1172                 break;
1173
1174         case -ENOSPC:
1175                 no_space(pool, cell);
1176                 break;
1177
1178         default:
1179                 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1180                             __func__, r);
1181                 set_pool_mode(pool, PM_READ_ONLY);
1182                 cell_error(pool, cell);
1183                 break;
1184         }
1185 }
1186
1187 static void process_bio(struct thin_c *tc, struct bio *bio)
1188 {
1189         int r;
1190         struct pool *pool = tc->pool;
1191         dm_block_t block = get_bio_block(tc, bio);
1192         struct dm_bio_prison_cell *cell;
1193         struct dm_cell_key key;
1194         struct dm_thin_lookup_result lookup_result;
1195
1196         /*
1197          * If cell is already occupied, then the block is already
1198          * being provisioned so we have nothing further to do here.
1199          */
1200         build_virtual_key(tc->td, block, &key);
1201         if (bio_detain(pool, &key, bio, &cell))
1202                 return;
1203
1204         r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1205         switch (r) {
1206         case 0:
1207                 if (lookup_result.shared) {
1208                         process_shared_bio(tc, bio, block, &lookup_result);
1209                         cell_defer_no_holder(tc, cell); /* FIXME: pass this cell into process_shared? */
1210                 } else {
1211                         inc_all_io_entry(pool, bio);
1212                         cell_defer_no_holder(tc, cell);
1213
1214                         remap_and_issue(tc, bio, lookup_result.block);
1215                 }
1216                 break;
1217
1218         case -ENODATA:
1219                 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1220                         inc_all_io_entry(pool, bio);
1221                         cell_defer_no_holder(tc, cell);
1222
1223                         remap_to_origin_and_issue(tc, bio);
1224                 } else
1225                         provision_block(tc, bio, block, cell);
1226                 break;
1227
1228         default:
1229                 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1230                             __func__, r);
1231                 cell_defer_no_holder(tc, cell);
1232                 bio_io_error(bio);
1233                 break;
1234         }
1235 }
1236
1237 static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1238 {
1239         int r;
1240         int rw = bio_data_dir(bio);
1241         dm_block_t block = get_bio_block(tc, bio);
1242         struct dm_thin_lookup_result lookup_result;
1243
1244         r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1245         switch (r) {
1246         case 0:
1247                 if (lookup_result.shared && (rw == WRITE) && bio->bi_size)
1248                         bio_io_error(bio);
1249                 else {
1250                         inc_all_io_entry(tc->pool, bio);
1251                         remap_and_issue(tc, bio, lookup_result.block);
1252                 }
1253                 break;
1254
1255         case -ENODATA:
1256                 if (rw != READ) {
1257                         bio_io_error(bio);
1258                         break;
1259                 }
1260
1261                 if (tc->origin_dev) {
1262                         inc_all_io_entry(tc->pool, bio);
1263                         remap_to_origin_and_issue(tc, bio);
1264                         break;
1265                 }
1266
1267                 zero_fill_bio(bio);
1268                 bio_endio(bio, 0);
1269                 break;
1270
1271         default:
1272                 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1273                             __func__, r);
1274                 bio_io_error(bio);
1275                 break;
1276         }
1277 }
1278
1279 static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1280 {
1281         bio_io_error(bio);
1282 }
1283
1284 static int need_commit_due_to_time(struct pool *pool)
1285 {
1286         return jiffies < pool->last_commit_jiffies ||
1287                jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1288 }
1289
1290 static void process_deferred_bios(struct pool *pool)
1291 {
1292         unsigned long flags;
1293         struct bio *bio;
1294         struct bio_list bios;
1295
1296         bio_list_init(&bios);
1297
1298         spin_lock_irqsave(&pool->lock, flags);
1299         bio_list_merge(&bios, &pool->deferred_bios);
1300         bio_list_init(&pool->deferred_bios);
1301         spin_unlock_irqrestore(&pool->lock, flags);
1302
1303         while ((bio = bio_list_pop(&bios))) {
1304                 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1305                 struct thin_c *tc = h->tc;
1306
1307                 /*
1308                  * If we've got no free new_mapping structs, and processing
1309                  * this bio might require one, we pause until there are some
1310                  * prepared mappings to process.
1311                  */
1312                 if (ensure_next_mapping(pool)) {
1313                         spin_lock_irqsave(&pool->lock, flags);
1314                         bio_list_merge(&pool->deferred_bios, &bios);
1315                         spin_unlock_irqrestore(&pool->lock, flags);
1316
1317                         break;
1318                 }
1319
1320                 if (bio->bi_rw & REQ_DISCARD)
1321                         pool->process_discard(tc, bio);
1322                 else
1323                         pool->process_bio(tc, bio);
1324         }
1325
1326         /*
1327          * If there are any deferred flush bios, we must commit
1328          * the metadata before issuing them.
1329          */
1330         bio_list_init(&bios);
1331         spin_lock_irqsave(&pool->lock, flags);
1332         bio_list_merge(&bios, &pool->deferred_flush_bios);
1333         bio_list_init(&pool->deferred_flush_bios);
1334         spin_unlock_irqrestore(&pool->lock, flags);
1335
1336         if (bio_list_empty(&bios) && !need_commit_due_to_time(pool))
1337                 return;
1338
1339         if (commit_or_fallback(pool)) {
1340                 while ((bio = bio_list_pop(&bios)))
1341                         bio_io_error(bio);
1342                 return;
1343         }
1344         pool->last_commit_jiffies = jiffies;
1345
1346         while ((bio = bio_list_pop(&bios)))
1347                 generic_make_request(bio);
1348 }
1349
1350 static void do_worker(struct work_struct *ws)
1351 {
1352         struct pool *pool = container_of(ws, struct pool, worker);
1353
1354         process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1355         process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1356         process_deferred_bios(pool);
1357 }
1358
1359 /*
1360  * We want to commit periodically so that not too much
1361  * unwritten data builds up.
1362  */
1363 static void do_waker(struct work_struct *ws)
1364 {
1365         struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1366         wake_worker(pool);
1367         queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1368 }
1369
1370 /*----------------------------------------------------------------*/
1371
1372 static enum pool_mode get_pool_mode(struct pool *pool)
1373 {
1374         return pool->pf.mode;
1375 }
1376
1377 static void set_pool_mode(struct pool *pool, enum pool_mode mode)
1378 {
1379         int r;
1380
1381         pool->pf.mode = mode;
1382
1383         switch (mode) {
1384         case PM_FAIL:
1385                 DMERR("switching pool to failure mode");
1386                 pool->process_bio = process_bio_fail;
1387                 pool->process_discard = process_bio_fail;
1388                 pool->process_prepared_mapping = process_prepared_mapping_fail;
1389                 pool->process_prepared_discard = process_prepared_discard_fail;
1390                 break;
1391
1392         case PM_READ_ONLY:
1393                 DMERR("switching pool to read-only mode");
1394                 r = dm_pool_abort_metadata(pool->pmd);
1395                 if (r) {
1396                         DMERR("aborting transaction failed");
1397                         set_pool_mode(pool, PM_FAIL);
1398                 } else {
1399                         dm_pool_metadata_read_only(pool->pmd);
1400                         pool->process_bio = process_bio_read_only;
1401                         pool->process_discard = process_discard;
1402                         pool->process_prepared_mapping = process_prepared_mapping_fail;
1403                         pool->process_prepared_discard = process_prepared_discard_passdown;
1404                 }
1405                 break;
1406
1407         case PM_WRITE:
1408                 pool->process_bio = process_bio;
1409                 pool->process_discard = process_discard;
1410                 pool->process_prepared_mapping = process_prepared_mapping;
1411                 pool->process_prepared_discard = process_prepared_discard;
1412                 break;
1413         }
1414 }
1415
1416 /*----------------------------------------------------------------*/
1417
1418 /*
1419  * Mapping functions.
1420  */
1421
1422 /*
1423  * Called only while mapping a thin bio to hand it over to the workqueue.
1424  */
1425 static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1426 {
1427         unsigned long flags;
1428         struct pool *pool = tc->pool;
1429
1430         spin_lock_irqsave(&pool->lock, flags);
1431         bio_list_add(&pool->deferred_bios, bio);
1432         spin_unlock_irqrestore(&pool->lock, flags);
1433
1434         wake_worker(pool);
1435 }
1436
1437 static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
1438 {
1439         struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1440
1441         h->tc = tc;
1442         h->shared_read_entry = NULL;
1443         h->all_io_entry = NULL;
1444         h->overwrite_mapping = NULL;
1445 }
1446
1447 /*
1448  * Non-blocking function called from the thin target's map function.
1449  */
1450 static int thin_bio_map(struct dm_target *ti, struct bio *bio)
1451 {
1452         int r;
1453         struct thin_c *tc = ti->private;
1454         dm_block_t block = get_bio_block(tc, bio);
1455         struct dm_thin_device *td = tc->td;
1456         struct dm_thin_lookup_result result;
1457         struct dm_bio_prison_cell cell1, cell2;
1458         struct dm_bio_prison_cell *cell_result;
1459         struct dm_cell_key key;
1460
1461         thin_hook_bio(tc, bio);
1462
1463         if (get_pool_mode(tc->pool) == PM_FAIL) {
1464                 bio_io_error(bio);
1465                 return DM_MAPIO_SUBMITTED;
1466         }
1467
1468         if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
1469                 thin_defer_bio(tc, bio);
1470                 return DM_MAPIO_SUBMITTED;
1471         }
1472
1473         r = dm_thin_find_block(td, block, 0, &result);
1474
1475         /*
1476          * Note that we defer readahead too.
1477          */
1478         switch (r) {
1479         case 0:
1480                 if (unlikely(result.shared)) {
1481                         /*
1482                          * We have a race condition here between the
1483                          * result.shared value returned by the lookup and
1484                          * snapshot creation, which may cause new
1485                          * sharing.
1486                          *
1487                          * To avoid this always quiesce the origin before
1488                          * taking the snap.  You want to do this anyway to
1489                          * ensure a consistent application view
1490                          * (i.e. lockfs).
1491                          *
1492                          * More distant ancestors are irrelevant. The
1493                          * shared flag will be set in their case.
1494                          */
1495                         thin_defer_bio(tc, bio);
1496                         return DM_MAPIO_SUBMITTED;
1497                 }
1498
1499                 build_virtual_key(tc->td, block, &key);
1500                 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
1501                         return DM_MAPIO_SUBMITTED;
1502
1503                 build_data_key(tc->td, result.block, &key);
1504                 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) {
1505                         cell_defer_no_holder_no_free(tc, &cell1);
1506                         return DM_MAPIO_SUBMITTED;
1507                 }
1508
1509                 inc_all_io_entry(tc->pool, bio);
1510                 cell_defer_no_holder_no_free(tc, &cell2);
1511                 cell_defer_no_holder_no_free(tc, &cell1);
1512
1513                 remap(tc, bio, result.block);
1514                 return DM_MAPIO_REMAPPED;
1515
1516         case -ENODATA:
1517                 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
1518                         /*
1519                          * This block isn't provisioned, and we have no way
1520                          * of doing so.  Just error it.
1521                          */
1522                         bio_io_error(bio);
1523                         return DM_MAPIO_SUBMITTED;
1524                 }
1525                 /* fall through */
1526
1527         case -EWOULDBLOCK:
1528                 /*
1529                  * In future, the failed dm_thin_find_block above could
1530                  * provide the hint to load the metadata into cache.
1531                  */
1532                 thin_defer_bio(tc, bio);
1533                 return DM_MAPIO_SUBMITTED;
1534
1535         default:
1536                 /*
1537                  * Must always call bio_io_error on failure.
1538                  * dm_thin_find_block can fail with -EINVAL if the
1539                  * pool is switched to fail-io mode.
1540                  */
1541                 bio_io_error(bio);
1542                 return DM_MAPIO_SUBMITTED;
1543         }
1544 }
1545
1546 static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1547 {
1548         int r;
1549         unsigned long flags;
1550         struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1551
1552         spin_lock_irqsave(&pt->pool->lock, flags);
1553         r = !bio_list_empty(&pt->pool->retry_on_resume_list);
1554         spin_unlock_irqrestore(&pt->pool->lock, flags);
1555
1556         if (!r) {
1557                 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1558                 r = bdi_congested(&q->backing_dev_info, bdi_bits);
1559         }
1560
1561         return r;
1562 }
1563
1564 static void __requeue_bios(struct pool *pool)
1565 {
1566         bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
1567         bio_list_init(&pool->retry_on_resume_list);
1568 }
1569
1570 /*----------------------------------------------------------------
1571  * Binding of control targets to a pool object
1572  *--------------------------------------------------------------*/
1573 static bool data_dev_supports_discard(struct pool_c *pt)
1574 {
1575         struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1576
1577         return q && blk_queue_discard(q);
1578 }
1579
1580 static bool is_factor(sector_t block_size, uint32_t n)
1581 {
1582         return !sector_div(block_size, n);
1583 }
1584
1585 /*
1586  * If discard_passdown was enabled verify that the data device
1587  * supports discards.  Disable discard_passdown if not.
1588  */
1589 static void disable_passdown_if_not_supported(struct pool_c *pt)
1590 {
1591         struct pool *pool = pt->pool;
1592         struct block_device *data_bdev = pt->data_dev->bdev;
1593         struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
1594         sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
1595         const char *reason = NULL;
1596         char buf[BDEVNAME_SIZE];
1597
1598         if (!pt->adjusted_pf.discard_passdown)
1599                 return;
1600
1601         if (!data_dev_supports_discard(pt))
1602                 reason = "discard unsupported";
1603
1604         else if (data_limits->max_discard_sectors < pool->sectors_per_block)
1605                 reason = "max discard sectors smaller than a block";
1606
1607         else if (data_limits->discard_granularity > block_size)
1608                 reason = "discard granularity larger than a block";
1609
1610         else if (!is_factor(block_size, data_limits->discard_granularity))
1611                 reason = "discard granularity not a factor of block size";
1612
1613         if (reason) {
1614                 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
1615                 pt->adjusted_pf.discard_passdown = false;
1616         }
1617 }
1618
1619 static int bind_control_target(struct pool *pool, struct dm_target *ti)
1620 {
1621         struct pool_c *pt = ti->private;
1622
1623         /*
1624          * We want to make sure that degraded pools are never upgraded.
1625          */
1626         enum pool_mode old_mode = pool->pf.mode;
1627         enum pool_mode new_mode = pt->adjusted_pf.mode;
1628
1629         if (old_mode > new_mode)
1630                 new_mode = old_mode;
1631
1632         pool->ti = ti;
1633         pool->low_water_blocks = pt->low_water_blocks;
1634         pool->pf = pt->adjusted_pf;
1635
1636         set_pool_mode(pool, new_mode);
1637
1638         return 0;
1639 }
1640
1641 static void unbind_control_target(struct pool *pool, struct dm_target *ti)
1642 {
1643         if (pool->ti == ti)
1644                 pool->ti = NULL;
1645 }
1646
1647 /*----------------------------------------------------------------
1648  * Pool creation
1649  *--------------------------------------------------------------*/
1650 /* Initialize pool features. */
1651 static void pool_features_init(struct pool_features *pf)
1652 {
1653         pf->mode = PM_WRITE;
1654         pf->zero_new_blocks = true;
1655         pf->discard_enabled = true;
1656         pf->discard_passdown = true;
1657 }
1658
1659 static void __pool_destroy(struct pool *pool)
1660 {
1661         __pool_table_remove(pool);
1662
1663         if (dm_pool_metadata_close(pool->pmd) < 0)
1664                 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1665
1666         dm_bio_prison_destroy(pool->prison);
1667         dm_kcopyd_client_destroy(pool->copier);
1668
1669         if (pool->wq)
1670                 destroy_workqueue(pool->wq);
1671
1672         if (pool->next_mapping)
1673                 mempool_free(pool->next_mapping, pool->mapping_pool);
1674         mempool_destroy(pool->mapping_pool);
1675         dm_deferred_set_destroy(pool->shared_read_ds);
1676         dm_deferred_set_destroy(pool->all_io_ds);
1677         kfree(pool);
1678 }
1679
1680 static struct kmem_cache *_new_mapping_cache;
1681
1682 static struct pool *pool_create(struct mapped_device *pool_md,
1683                                 struct block_device *metadata_dev,
1684                                 unsigned long block_size,
1685                                 int read_only, char **error)
1686 {
1687         int r;
1688         void *err_p;
1689         struct pool *pool;
1690         struct dm_pool_metadata *pmd;
1691         bool format_device = read_only ? false : true;
1692
1693         pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
1694         if (IS_ERR(pmd)) {
1695                 *error = "Error creating metadata object";
1696                 return (struct pool *)pmd;
1697         }
1698
1699         pool = kmalloc(sizeof(*pool), GFP_KERNEL);
1700         if (!pool) {
1701                 *error = "Error allocating memory for pool";
1702                 err_p = ERR_PTR(-ENOMEM);
1703                 goto bad_pool;
1704         }
1705
1706         pool->pmd = pmd;
1707         pool->sectors_per_block = block_size;
1708         if (block_size & (block_size - 1))
1709                 pool->sectors_per_block_shift = -1;
1710         else
1711                 pool->sectors_per_block_shift = __ffs(block_size);
1712         pool->low_water_blocks = 0;
1713         pool_features_init(&pool->pf);
1714         pool->prison = dm_bio_prison_create(PRISON_CELLS);
1715         if (!pool->prison) {
1716                 *error = "Error creating pool's bio prison";
1717                 err_p = ERR_PTR(-ENOMEM);
1718                 goto bad_prison;
1719         }
1720
1721         pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
1722         if (IS_ERR(pool->copier)) {
1723                 r = PTR_ERR(pool->copier);
1724                 *error = "Error creating pool's kcopyd client";
1725                 err_p = ERR_PTR(r);
1726                 goto bad_kcopyd_client;
1727         }
1728
1729         /*
1730          * Create singlethreaded workqueue that will service all devices
1731          * that use this metadata.
1732          */
1733         pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1734         if (!pool->wq) {
1735                 *error = "Error creating pool's workqueue";
1736                 err_p = ERR_PTR(-ENOMEM);
1737                 goto bad_wq;
1738         }
1739
1740         INIT_WORK(&pool->worker, do_worker);
1741         INIT_DELAYED_WORK(&pool->waker, do_waker);
1742         spin_lock_init(&pool->lock);
1743         bio_list_init(&pool->deferred_bios);
1744         bio_list_init(&pool->deferred_flush_bios);
1745         INIT_LIST_HEAD(&pool->prepared_mappings);
1746         INIT_LIST_HEAD(&pool->prepared_discards);
1747         pool->low_water_triggered = 0;
1748         pool->no_free_space = 0;
1749         bio_list_init(&pool->retry_on_resume_list);
1750
1751         pool->shared_read_ds = dm_deferred_set_create();
1752         if (!pool->shared_read_ds) {
1753                 *error = "Error creating pool's shared read deferred set";
1754                 err_p = ERR_PTR(-ENOMEM);
1755                 goto bad_shared_read_ds;
1756         }
1757
1758         pool->all_io_ds = dm_deferred_set_create();
1759         if (!pool->all_io_ds) {
1760                 *error = "Error creating pool's all io deferred set";
1761                 err_p = ERR_PTR(-ENOMEM);
1762                 goto bad_all_io_ds;
1763         }
1764
1765         pool->next_mapping = NULL;
1766         pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
1767                                                       _new_mapping_cache);
1768         if (!pool->mapping_pool) {
1769                 *error = "Error creating pool's mapping mempool";
1770                 err_p = ERR_PTR(-ENOMEM);
1771                 goto bad_mapping_pool;
1772         }
1773
1774         pool->ref_count = 1;
1775         pool->last_commit_jiffies = jiffies;
1776         pool->pool_md = pool_md;
1777         pool->md_dev = metadata_dev;
1778         __pool_table_insert(pool);
1779
1780         return pool;
1781
1782 bad_mapping_pool:
1783         dm_deferred_set_destroy(pool->all_io_ds);
1784 bad_all_io_ds:
1785         dm_deferred_set_destroy(pool->shared_read_ds);
1786 bad_shared_read_ds:
1787         destroy_workqueue(pool->wq);
1788 bad_wq:
1789         dm_kcopyd_client_destroy(pool->copier);
1790 bad_kcopyd_client:
1791         dm_bio_prison_destroy(pool->prison);
1792 bad_prison:
1793         kfree(pool);
1794 bad_pool:
1795         if (dm_pool_metadata_close(pmd))
1796                 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
1797
1798         return err_p;
1799 }
1800
1801 static void __pool_inc(struct pool *pool)
1802 {
1803         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1804         pool->ref_count++;
1805 }
1806
1807 static void __pool_dec(struct pool *pool)
1808 {
1809         BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
1810         BUG_ON(!pool->ref_count);
1811         if (!--pool->ref_count)
1812                 __pool_destroy(pool);
1813 }
1814
1815 static struct pool *__pool_find(struct mapped_device *pool_md,
1816                                 struct block_device *metadata_dev,
1817                                 unsigned long block_size, int read_only,
1818                                 char **error, int *created)
1819 {
1820         struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
1821
1822         if (pool) {
1823                 if (pool->pool_md != pool_md) {
1824                         *error = "metadata device already in use by a pool";
1825                         return ERR_PTR(-EBUSY);
1826                 }
1827                 __pool_inc(pool);
1828
1829         } else {
1830                 pool = __pool_table_lookup(pool_md);
1831                 if (pool) {
1832                         if (pool->md_dev != metadata_dev) {
1833                                 *error = "different pool cannot replace a pool";
1834                                 return ERR_PTR(-EINVAL);
1835                         }
1836                         __pool_inc(pool);
1837
1838                 } else {
1839                         pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
1840                         *created = 1;
1841                 }
1842         }
1843
1844         return pool;
1845 }
1846
1847 /*----------------------------------------------------------------
1848  * Pool target methods
1849  *--------------------------------------------------------------*/
1850 static void pool_dtr(struct dm_target *ti)
1851 {
1852         struct pool_c *pt = ti->private;
1853
1854         mutex_lock(&dm_thin_pool_table.mutex);
1855
1856         unbind_control_target(pt->pool, ti);
1857         __pool_dec(pt->pool);
1858         dm_put_device(ti, pt->metadata_dev);
1859         dm_put_device(ti, pt->data_dev);
1860         kfree(pt);
1861
1862         mutex_unlock(&dm_thin_pool_table.mutex);
1863 }
1864
1865 static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
1866                                struct dm_target *ti)
1867 {
1868         int r;
1869         unsigned argc;
1870         const char *arg_name;
1871
1872         static struct dm_arg _args[] = {
1873                 {0, 3, "Invalid number of pool feature arguments"},
1874         };
1875
1876         /*
1877          * No feature arguments supplied.
1878          */
1879         if (!as->argc)
1880                 return 0;
1881
1882         r = dm_read_arg_group(_args, as, &argc, &ti->error);
1883         if (r)
1884                 return -EINVAL;
1885
1886         while (argc && !r) {
1887                 arg_name = dm_shift_arg(as);
1888                 argc--;
1889
1890                 if (!strcasecmp(arg_name, "skip_block_zeroing"))
1891                         pf->zero_new_blocks = false;
1892
1893                 else if (!strcasecmp(arg_name, "ignore_discard"))
1894                         pf->discard_enabled = false;
1895
1896                 else if (!strcasecmp(arg_name, "no_discard_passdown"))
1897                         pf->discard_passdown = false;
1898
1899                 else if (!strcasecmp(arg_name, "read_only"))
1900                         pf->mode = PM_READ_ONLY;
1901
1902                 else {
1903                         ti->error = "Unrecognised pool feature requested";
1904                         r = -EINVAL;
1905                         break;
1906                 }
1907         }
1908
1909         return r;
1910 }
1911
1912 /*
1913  * thin-pool <metadata dev> <data dev>
1914  *           <data block size (sectors)>
1915  *           <low water mark (blocks)>
1916  *           [<#feature args> [<arg>]*]
1917  *
1918  * Optional feature arguments are:
1919  *           skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
1920  *           ignore_discard: disable discard
1921  *           no_discard_passdown: don't pass discards down to the data device
1922  */
1923 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
1924 {
1925         int r, pool_created = 0;
1926         struct pool_c *pt;
1927         struct pool *pool;
1928         struct pool_features pf;
1929         struct dm_arg_set as;
1930         struct dm_dev *data_dev;
1931         unsigned long block_size;
1932         dm_block_t low_water_blocks;
1933         struct dm_dev *metadata_dev;
1934         sector_t metadata_dev_size;
1935         char b[BDEVNAME_SIZE];
1936
1937         /*
1938          * FIXME Remove validation from scope of lock.
1939          */
1940         mutex_lock(&dm_thin_pool_table.mutex);
1941
1942         if (argc < 4) {
1943                 ti->error = "Invalid argument count";
1944                 r = -EINVAL;
1945                 goto out_unlock;
1946         }
1947         as.argc = argc;
1948         as.argv = argv;
1949
1950         r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev);
1951         if (r) {
1952                 ti->error = "Error opening metadata block device";
1953                 goto out_unlock;
1954         }
1955
1956         metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT;
1957         if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
1958                 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1959                        bdevname(metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
1960
1961         r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
1962         if (r) {
1963                 ti->error = "Error getting data device";
1964                 goto out_metadata;
1965         }
1966
1967         if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
1968             block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
1969             block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
1970             block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
1971                 ti->error = "Invalid block size";
1972                 r = -EINVAL;
1973                 goto out;
1974         }
1975
1976         if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
1977                 ti->error = "Invalid low water mark";
1978                 r = -EINVAL;
1979                 goto out;
1980         }
1981
1982         /*
1983          * Set default pool features.
1984          */
1985         pool_features_init(&pf);
1986
1987         dm_consume_args(&as, 4);
1988         r = parse_pool_features(&as, &pf, ti);
1989         if (r)
1990                 goto out;
1991
1992         pt = kzalloc(sizeof(*pt), GFP_KERNEL);
1993         if (!pt) {
1994                 r = -ENOMEM;
1995                 goto out;
1996         }
1997
1998         pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
1999                            block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
2000         if (IS_ERR(pool)) {
2001                 r = PTR_ERR(pool);
2002                 goto out_free_pt;
2003         }
2004
2005         /*
2006          * 'pool_created' reflects whether this is the first table load.
2007          * Top level discard support is not allowed to be changed after
2008          * initial load.  This would require a pool reload to trigger thin
2009          * device changes.
2010          */
2011         if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
2012                 ti->error = "Discard support cannot be disabled once enabled";
2013                 r = -EINVAL;
2014                 goto out_flags_changed;
2015         }
2016
2017         pt->pool = pool;
2018         pt->ti = ti;
2019         pt->metadata_dev = metadata_dev;
2020         pt->data_dev = data_dev;
2021         pt->low_water_blocks = low_water_blocks;
2022         pt->adjusted_pf = pt->requested_pf = pf;
2023         ti->num_flush_bios = 1;
2024
2025         /*
2026          * Only need to enable discards if the pool should pass
2027          * them down to the data device.  The thin device's discard
2028          * processing will cause mappings to be removed from the btree.
2029          */
2030         if (pf.discard_enabled && pf.discard_passdown) {
2031                 ti->num_discard_bios = 1;
2032
2033                 /*
2034                  * Setting 'discards_supported' circumvents the normal
2035                  * stacking of discard limits (this keeps the pool and
2036                  * thin devices' discard limits consistent).
2037                  */
2038                 ti->discards_supported = true;
2039                 ti->discard_zeroes_data_unsupported = true;
2040         }
2041         ti->private = pt;
2042
2043         pt->callbacks.congested_fn = pool_is_congested;
2044         dm_table_add_target_callbacks(ti->table, &pt->callbacks);
2045
2046         mutex_unlock(&dm_thin_pool_table.mutex);
2047
2048         return 0;
2049
2050 out_flags_changed:
2051         __pool_dec(pool);
2052 out_free_pt:
2053         kfree(pt);
2054 out:
2055         dm_put_device(ti, data_dev);
2056 out_metadata:
2057         dm_put_device(ti, metadata_dev);
2058 out_unlock:
2059         mutex_unlock(&dm_thin_pool_table.mutex);
2060
2061         return r;
2062 }
2063
2064 static int pool_map(struct dm_target *ti, struct bio *bio)
2065 {
2066         int r;
2067         struct pool_c *pt = ti->private;
2068         struct pool *pool = pt->pool;
2069         unsigned long flags;
2070
2071         /*
2072          * As this is a singleton target, ti->begin is always zero.
2073          */
2074         spin_lock_irqsave(&pool->lock, flags);
2075         bio->bi_bdev = pt->data_dev->bdev;
2076         r = DM_MAPIO_REMAPPED;
2077         spin_unlock_irqrestore(&pool->lock, flags);
2078
2079         return r;
2080 }
2081
2082 /*
2083  * Retrieves the number of blocks of the data device from
2084  * the superblock and compares it to the actual device size,
2085  * thus resizing the data device in case it has grown.
2086  *
2087  * This both copes with opening preallocated data devices in the ctr
2088  * being followed by a resume
2089  * -and-
2090  * calling the resume method individually after userspace has
2091  * grown the data device in reaction to a table event.
2092  */
2093 static int pool_preresume(struct dm_target *ti)
2094 {
2095         int r;
2096         struct pool_c *pt = ti->private;
2097         struct pool *pool = pt->pool;
2098         sector_t data_size = ti->len;
2099         dm_block_t sb_data_size;
2100
2101         /*
2102          * Take control of the pool object.
2103          */
2104         r = bind_control_target(pool, ti);
2105         if (r)
2106                 return r;
2107
2108         (void) sector_div(data_size, pool->sectors_per_block);
2109
2110         r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2111         if (r) {
2112                 DMERR("failed to retrieve data device size");
2113                 return r;
2114         }
2115
2116         if (data_size < sb_data_size) {
2117                 DMERR("pool target too small, is %llu blocks (expected %llu)",
2118                       (unsigned long long)data_size, sb_data_size);
2119                 return -EINVAL;
2120
2121         } else if (data_size > sb_data_size) {
2122                 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2123                 if (r) {
2124                         DMERR("failed to resize data device");
2125                         /* FIXME Stricter than necessary: Rollback transaction instead here */
2126                         set_pool_mode(pool, PM_READ_ONLY);
2127                         return r;
2128                 }
2129
2130                 (void) commit_or_fallback(pool);
2131         }
2132
2133         return 0;
2134 }
2135
2136 static void pool_resume(struct dm_target *ti)
2137 {
2138         struct pool_c *pt = ti->private;
2139         struct pool *pool = pt->pool;
2140         unsigned long flags;
2141
2142         spin_lock_irqsave(&pool->lock, flags);
2143         pool->low_water_triggered = 0;
2144         pool->no_free_space = 0;
2145         __requeue_bios(pool);
2146         spin_unlock_irqrestore(&pool->lock, flags);
2147
2148         do_waker(&pool->waker.work);
2149 }
2150
2151 static void pool_postsuspend(struct dm_target *ti)
2152 {
2153         struct pool_c *pt = ti->private;
2154         struct pool *pool = pt->pool;
2155
2156         cancel_delayed_work(&pool->waker);
2157         flush_workqueue(pool->wq);
2158         (void) commit_or_fallback(pool);
2159 }
2160
2161 static int check_arg_count(unsigned argc, unsigned args_required)
2162 {
2163         if (argc != args_required) {
2164                 DMWARN("Message received with %u arguments instead of %u.",
2165                        argc, args_required);
2166                 return -EINVAL;
2167         }
2168
2169         return 0;
2170 }
2171
2172 static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
2173 {
2174         if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
2175             *dev_id <= MAX_DEV_ID)
2176                 return 0;
2177
2178         if (warning)
2179                 DMWARN("Message received with invalid device id: %s", arg);
2180
2181         return -EINVAL;
2182 }
2183
2184 static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
2185 {
2186         dm_thin_id dev_id;
2187         int r;
2188
2189         r = check_arg_count(argc, 2);
2190         if (r)
2191                 return r;
2192
2193         r = read_dev_id(argv[1], &dev_id, 1);
2194         if (r)
2195                 return r;
2196
2197         r = dm_pool_create_thin(pool->pmd, dev_id);
2198         if (r) {
2199                 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2200                        argv[1]);
2201                 return r;
2202         }
2203
2204         return 0;
2205 }
2206
2207 static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2208 {
2209         dm_thin_id dev_id;
2210         dm_thin_id origin_dev_id;
2211         int r;
2212
2213         r = check_arg_count(argc, 3);
2214         if (r)
2215                 return r;
2216
2217         r = read_dev_id(argv[1], &dev_id, 1);
2218         if (r)
2219                 return r;
2220
2221         r = read_dev_id(argv[2], &origin_dev_id, 1);
2222         if (r)
2223                 return r;
2224
2225         r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
2226         if (r) {
2227                 DMWARN("Creation of new snapshot %s of device %s failed.",
2228                        argv[1], argv[2]);
2229                 return r;
2230         }
2231
2232         return 0;
2233 }
2234
2235 static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2236 {
2237         dm_thin_id dev_id;
2238         int r;
2239
2240         r = check_arg_count(argc, 2);
2241         if (r)
2242                 return r;
2243
2244         r = read_dev_id(argv[1], &dev_id, 1);
2245         if (r)
2246                 return r;
2247
2248         r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2249         if (r)
2250                 DMWARN("Deletion of thin device %s failed.", argv[1]);
2251
2252         return r;
2253 }
2254
2255 static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2256 {
2257         dm_thin_id old_id, new_id;
2258         int r;
2259
2260         r = check_arg_count(argc, 3);
2261         if (r)
2262                 return r;
2263
2264         if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2265                 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2266                 return -EINVAL;
2267         }
2268
2269         if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2270                 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2271                 return -EINVAL;
2272         }
2273
2274         r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2275         if (r) {
2276                 DMWARN("Failed to change transaction id from %s to %s.",
2277                        argv[1], argv[2]);
2278                 return r;
2279         }
2280
2281         return 0;
2282 }
2283
2284 static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2285 {
2286         int r;
2287
2288         r = check_arg_count(argc, 1);
2289         if (r)
2290                 return r;
2291
2292         (void) commit_or_fallback(pool);
2293
2294         r = dm_pool_reserve_metadata_snap(pool->pmd);
2295         if (r)
2296                 DMWARN("reserve_metadata_snap message failed.");
2297
2298         return r;
2299 }
2300
2301 static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2302 {
2303         int r;
2304
2305         r = check_arg_count(argc, 1);
2306         if (r)
2307                 return r;
2308
2309         r = dm_pool_release_metadata_snap(pool->pmd);
2310         if (r)
2311                 DMWARN("release_metadata_snap message failed.");
2312
2313         return r;
2314 }
2315
2316 /*
2317  * Messages supported:
2318  *   create_thin        <dev_id>
2319  *   create_snap        <dev_id> <origin_id>
2320  *   delete             <dev_id>
2321  *   trim               <dev_id> <new_size_in_sectors>
2322  *   set_transaction_id <current_trans_id> <new_trans_id>
2323  *   reserve_metadata_snap
2324  *   release_metadata_snap
2325  */
2326 static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2327 {
2328         int r = -EINVAL;
2329         struct pool_c *pt = ti->private;
2330         struct pool *pool = pt->pool;
2331
2332         if (!strcasecmp(argv[0], "create_thin"))
2333                 r = process_create_thin_mesg(argc, argv, pool);
2334
2335         else if (!strcasecmp(argv[0], "create_snap"))
2336                 r = process_create_snap_mesg(argc, argv, pool);
2337
2338         else if (!strcasecmp(argv[0], "delete"))
2339                 r = process_delete_mesg(argc, argv, pool);
2340
2341         else if (!strcasecmp(argv[0], "set_transaction_id"))
2342                 r = process_set_transaction_id_mesg(argc, argv, pool);
2343
2344         else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
2345                 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
2346
2347         else if (!strcasecmp(argv[0], "release_metadata_snap"))
2348                 r = process_release_metadata_snap_mesg(argc, argv, pool);
2349
2350         else
2351                 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2352
2353         if (!r)
2354                 (void) commit_or_fallback(pool);
2355
2356         return r;
2357 }
2358
2359 static void emit_flags(struct pool_features *pf, char *result,
2360                        unsigned sz, unsigned maxlen)
2361 {
2362         unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
2363                 !pf->discard_passdown + (pf->mode == PM_READ_ONLY);
2364         DMEMIT("%u ", count);
2365
2366         if (!pf->zero_new_blocks)
2367                 DMEMIT("skip_block_zeroing ");
2368
2369         if (!pf->discard_enabled)
2370                 DMEMIT("ignore_discard ");
2371
2372         if (!pf->discard_passdown)
2373                 DMEMIT("no_discard_passdown ");
2374
2375         if (pf->mode == PM_READ_ONLY)
2376                 DMEMIT("read_only ");
2377 }
2378
2379 /*
2380  * Status line is:
2381  *    <transaction id> <used metadata sectors>/<total metadata sectors>
2382  *    <used data sectors>/<total data sectors> <held metadata root>
2383  */
2384 static void pool_status(struct dm_target *ti, status_type_t type,
2385                         unsigned status_flags, char *result, unsigned maxlen)
2386 {
2387         int r;
2388         unsigned sz = 0;
2389         uint64_t transaction_id;
2390         dm_block_t nr_free_blocks_data;
2391         dm_block_t nr_free_blocks_metadata;
2392         dm_block_t nr_blocks_data;
2393         dm_block_t nr_blocks_metadata;
2394         dm_block_t held_root;
2395         char buf[BDEVNAME_SIZE];
2396         char buf2[BDEVNAME_SIZE];
2397         struct pool_c *pt = ti->private;
2398         struct pool *pool = pt->pool;
2399
2400         switch (type) {
2401         case STATUSTYPE_INFO:
2402                 if (get_pool_mode(pool) == PM_FAIL) {
2403                         DMEMIT("Fail");
2404                         break;
2405                 }
2406
2407                 /* Commit to ensure statistics aren't out-of-date */
2408                 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
2409                         (void) commit_or_fallback(pool);
2410
2411                 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
2412                 if (r) {
2413                         DMERR("dm_pool_get_metadata_transaction_id returned %d", r);
2414                         goto err;
2415                 }
2416
2417                 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
2418                 if (r) {
2419                         DMERR("dm_pool_get_free_metadata_block_count returned %d", r);
2420                         goto err;
2421                 }
2422
2423                 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2424                 if (r) {
2425                         DMERR("dm_pool_get_metadata_dev_size returned %d", r);
2426                         goto err;
2427                 }
2428
2429                 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
2430                 if (r) {
2431                         DMERR("dm_pool_get_free_block_count returned %d", r);
2432                         goto err;
2433                 }
2434
2435                 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2436                 if (r) {
2437                         DMERR("dm_pool_get_data_dev_size returned %d", r);
2438                         goto err;
2439                 }
2440
2441                 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
2442                 if (r) {
2443                         DMERR("dm_pool_get_metadata_snap returned %d", r);
2444                         goto err;
2445                 }
2446
2447                 DMEMIT("%llu %llu/%llu %llu/%llu ",
2448                        (unsigned long long)transaction_id,
2449                        (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2450                        (unsigned long long)nr_blocks_metadata,
2451                        (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
2452                        (unsigned long long)nr_blocks_data);
2453
2454                 if (held_root)
2455                         DMEMIT("%llu ", held_root);
2456                 else
2457                         DMEMIT("- ");
2458
2459                 if (pool->pf.mode == PM_READ_ONLY)
2460                         DMEMIT("ro ");
2461                 else
2462                         DMEMIT("rw ");
2463
2464                 if (!pool->pf.discard_enabled)
2465                         DMEMIT("ignore_discard");
2466                 else if (pool->pf.discard_passdown)
2467                         DMEMIT("discard_passdown");
2468                 else
2469                         DMEMIT("no_discard_passdown");
2470
2471                 break;
2472
2473         case STATUSTYPE_TABLE:
2474                 DMEMIT("%s %s %lu %llu ",
2475                        format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
2476                        format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
2477                        (unsigned long)pool->sectors_per_block,
2478                        (unsigned long long)pt->low_water_blocks);
2479                 emit_flags(&pt->requested_pf, result, sz, maxlen);
2480                 break;
2481         }
2482         return;
2483
2484 err:
2485         DMEMIT("Error");
2486 }
2487
2488 static int pool_iterate_devices(struct dm_target *ti,
2489                                 iterate_devices_callout_fn fn, void *data)
2490 {
2491         struct pool_c *pt = ti->private;
2492
2493         return fn(ti, pt->data_dev, 0, ti->len, data);
2494 }
2495
2496 static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
2497                       struct bio_vec *biovec, int max_size)
2498 {
2499         struct pool_c *pt = ti->private;
2500         struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2501
2502         if (!q->merge_bvec_fn)
2503                 return max_size;
2504
2505         bvm->bi_bdev = pt->data_dev->bdev;
2506
2507         return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
2508 }
2509
2510 static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
2511 {
2512         struct pool *pool = pt->pool;
2513         struct queue_limits *data_limits;
2514
2515         limits->max_discard_sectors = pool->sectors_per_block;
2516
2517         /*
2518          * discard_granularity is just a hint, and not enforced.
2519          */
2520         if (pt->adjusted_pf.discard_passdown) {
2521                 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
2522                 limits->discard_granularity = data_limits->discard_granularity;
2523         } else
2524                 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
2525 }
2526
2527 static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
2528 {
2529         struct pool_c *pt = ti->private;
2530         struct pool *pool = pt->pool;
2531
2532         blk_limits_io_min(limits, 0);
2533         blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
2534
2535         /*
2536          * pt->adjusted_pf is a staging area for the actual features to use.
2537          * They get transferred to the live pool in bind_control_target()
2538          * called from pool_preresume().
2539          */
2540         if (!pt->adjusted_pf.discard_enabled)
2541                 return;
2542
2543         disable_passdown_if_not_supported(pt);
2544
2545         set_discard_limits(pt, limits);
2546 }
2547
2548 static struct target_type pool_target = {
2549         .name = "thin-pool",
2550         .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
2551                     DM_TARGET_IMMUTABLE,
2552         .version = {1, 7, 0},
2553         .module = THIS_MODULE,
2554         .ctr = pool_ctr,
2555         .dtr = pool_dtr,
2556         .map = pool_map,
2557         .postsuspend = pool_postsuspend,
2558         .preresume = pool_preresume,
2559         .resume = pool_resume,
2560         .message = pool_message,
2561         .status = pool_status,
2562         .merge = pool_merge,
2563         .iterate_devices = pool_iterate_devices,
2564         .io_hints = pool_io_hints,
2565 };
2566
2567 /*----------------------------------------------------------------
2568  * Thin target methods
2569  *--------------------------------------------------------------*/
2570 static void thin_dtr(struct dm_target *ti)
2571 {
2572         struct thin_c *tc = ti->private;
2573
2574         mutex_lock(&dm_thin_pool_table.mutex);
2575
2576         __pool_dec(tc->pool);
2577         dm_pool_close_thin_device(tc->td);
2578         dm_put_device(ti, tc->pool_dev);
2579         if (tc->origin_dev)
2580                 dm_put_device(ti, tc->origin_dev);
2581         kfree(tc);
2582
2583         mutex_unlock(&dm_thin_pool_table.mutex);
2584 }
2585
2586 /*
2587  * Thin target parameters:
2588  *
2589  * <pool_dev> <dev_id> [origin_dev]
2590  *
2591  * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
2592  * dev_id: the internal device identifier
2593  * origin_dev: a device external to the pool that should act as the origin
2594  *
2595  * If the pool device has discards disabled, they get disabled for the thin
2596  * device as well.
2597  */
2598 static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
2599 {
2600         int r;
2601         struct thin_c *tc;
2602         struct dm_dev *pool_dev, *origin_dev;
2603         struct mapped_device *pool_md;
2604
2605         mutex_lock(&dm_thin_pool_table.mutex);
2606
2607         if (argc != 2 && argc != 3) {
2608                 ti->error = "Invalid argument count";
2609                 r = -EINVAL;
2610                 goto out_unlock;
2611         }
2612
2613         tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
2614         if (!tc) {
2615                 ti->error = "Out of memory";
2616                 r = -ENOMEM;
2617                 goto out_unlock;
2618         }
2619
2620         if (argc == 3) {
2621                 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
2622                 if (r) {
2623                         ti->error = "Error opening origin device";
2624                         goto bad_origin_dev;
2625                 }
2626                 tc->origin_dev = origin_dev;
2627         }
2628
2629         r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
2630         if (r) {
2631                 ti->error = "Error opening pool device";
2632                 goto bad_pool_dev;
2633         }
2634         tc->pool_dev = pool_dev;
2635
2636         if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
2637                 ti->error = "Invalid device id";
2638                 r = -EINVAL;
2639                 goto bad_common;
2640         }
2641
2642         pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
2643         if (!pool_md) {
2644                 ti->error = "Couldn't get pool mapped device";
2645                 r = -EINVAL;
2646                 goto bad_common;
2647         }
2648
2649         tc->pool = __pool_table_lookup(pool_md);
2650         if (!tc->pool) {
2651                 ti->error = "Couldn't find pool object";
2652                 r = -EINVAL;
2653                 goto bad_pool_lookup;
2654         }
2655         __pool_inc(tc->pool);
2656
2657         if (get_pool_mode(tc->pool) == PM_FAIL) {
2658                 ti->error = "Couldn't open thin device, Pool is in fail mode";
2659                 goto bad_thin_open;
2660         }
2661
2662         r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
2663         if (r) {
2664                 ti->error = "Couldn't open thin internal device";
2665                 goto bad_thin_open;
2666         }
2667
2668         r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
2669         if (r)
2670                 goto bad_thin_open;
2671
2672         ti->num_flush_bios = 1;
2673         ti->flush_supported = true;
2674         ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
2675
2676         /* In case the pool supports discards, pass them on. */
2677         if (tc->pool->pf.discard_enabled) {
2678                 ti->discards_supported = true;
2679                 ti->num_discard_bios = 1;
2680                 ti->discard_zeroes_data_unsupported = true;
2681                 /* Discard bios must be split on a block boundary */
2682                 ti->split_discard_bios = true;
2683         }
2684
2685         dm_put(pool_md);
2686
2687         mutex_unlock(&dm_thin_pool_table.mutex);
2688
2689         return 0;
2690
2691 bad_thin_open:
2692         __pool_dec(tc->pool);
2693 bad_pool_lookup:
2694         dm_put(pool_md);
2695 bad_common:
2696         dm_put_device(ti, tc->pool_dev);
2697 bad_pool_dev:
2698         if (tc->origin_dev)
2699                 dm_put_device(ti, tc->origin_dev);
2700 bad_origin_dev:
2701         kfree(tc);
2702 out_unlock:
2703         mutex_unlock(&dm_thin_pool_table.mutex);
2704
2705         return r;
2706 }
2707
2708 static int thin_map(struct dm_target *ti, struct bio *bio)
2709 {
2710         bio->bi_sector = dm_target_offset(ti, bio->bi_sector);
2711
2712         return thin_bio_map(ti, bio);
2713 }
2714
2715 static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
2716 {
2717         unsigned long flags;
2718         struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2719         struct list_head work;
2720         struct dm_thin_new_mapping *m, *tmp;
2721         struct pool *pool = h->tc->pool;
2722
2723         if (h->shared_read_entry) {
2724                 INIT_LIST_HEAD(&work);
2725                 dm_deferred_entry_dec(h->shared_read_entry, &work);
2726
2727                 spin_lock_irqsave(&pool->lock, flags);
2728                 list_for_each_entry_safe(m, tmp, &work, list) {
2729                         list_del(&m->list);
2730                         m->quiesced = 1;
2731                         __maybe_add_mapping(m);
2732                 }
2733                 spin_unlock_irqrestore(&pool->lock, flags);
2734         }
2735
2736         if (h->all_io_entry) {
2737                 INIT_LIST_HEAD(&work);
2738                 dm_deferred_entry_dec(h->all_io_entry, &work);
2739                 if (!list_empty(&work)) {
2740                         spin_lock_irqsave(&pool->lock, flags);
2741                         list_for_each_entry_safe(m, tmp, &work, list)
2742                                 list_add(&m->list, &pool->prepared_discards);
2743                         spin_unlock_irqrestore(&pool->lock, flags);
2744                         wake_worker(pool);
2745                 }
2746         }
2747
2748         return 0;
2749 }
2750
2751 static void thin_postsuspend(struct dm_target *ti)
2752 {
2753         if (dm_noflush_suspending(ti))
2754                 requeue_io((struct thin_c *)ti->private);
2755 }
2756
2757 /*
2758  * <nr mapped sectors> <highest mapped sector>
2759  */
2760 static void thin_status(struct dm_target *ti, status_type_t type,
2761                         unsigned status_flags, char *result, unsigned maxlen)
2762 {
2763         int r;
2764         ssize_t sz = 0;
2765         dm_block_t mapped, highest;
2766         char buf[BDEVNAME_SIZE];
2767         struct thin_c *tc = ti->private;
2768
2769         if (get_pool_mode(tc->pool) == PM_FAIL) {
2770                 DMEMIT("Fail");
2771                 return;
2772         }
2773
2774         if (!tc->td)
2775                 DMEMIT("-");
2776         else {
2777                 switch (type) {
2778                 case STATUSTYPE_INFO:
2779                         r = dm_thin_get_mapped_count(tc->td, &mapped);
2780                         if (r) {
2781                                 DMERR("dm_thin_get_mapped_count returned %d", r);
2782                                 goto err;
2783                         }
2784
2785                         r = dm_thin_get_highest_mapped_block(tc->td, &highest);
2786                         if (r < 0) {
2787                                 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
2788                                 goto err;
2789                         }
2790
2791                         DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
2792                         if (r)
2793                                 DMEMIT("%llu", ((highest + 1) *
2794                                                 tc->pool->sectors_per_block) - 1);
2795                         else
2796                                 DMEMIT("-");
2797                         break;
2798
2799                 case STATUSTYPE_TABLE:
2800                         DMEMIT("%s %lu",
2801                                format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
2802                                (unsigned long) tc->dev_id);
2803                         if (tc->origin_dev)
2804                                 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
2805                         break;
2806                 }
2807         }
2808
2809         return;
2810
2811 err:
2812         DMEMIT("Error");
2813 }
2814
2815 static int thin_iterate_devices(struct dm_target *ti,
2816                                 iterate_devices_callout_fn fn, void *data)
2817 {
2818         sector_t blocks;
2819         struct thin_c *tc = ti->private;
2820         struct pool *pool = tc->pool;
2821
2822         /*
2823          * We can't call dm_pool_get_data_dev_size() since that blocks.  So
2824          * we follow a more convoluted path through to the pool's target.
2825          */
2826         if (!pool->ti)
2827                 return 0;       /* nothing is bound */
2828
2829         blocks = pool->ti->len;
2830         (void) sector_div(blocks, pool->sectors_per_block);
2831         if (blocks)
2832                 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
2833
2834         return 0;
2835 }
2836
2837 static struct target_type thin_target = {
2838         .name = "thin",
2839         .version = {1, 8, 0},
2840         .module = THIS_MODULE,
2841         .ctr = thin_ctr,
2842         .dtr = thin_dtr,
2843         .map = thin_map,
2844         .end_io = thin_endio,
2845         .postsuspend = thin_postsuspend,
2846         .status = thin_status,
2847         .iterate_devices = thin_iterate_devices,
2848 };
2849
2850 /*----------------------------------------------------------------*/
2851
2852 static int __init dm_thin_init(void)
2853 {
2854         int r;
2855
2856         pool_table_init();
2857
2858         r = dm_register_target(&thin_target);
2859         if (r)
2860                 return r;
2861
2862         r = dm_register_target(&pool_target);
2863         if (r)
2864                 goto bad_pool_target;
2865
2866         r = -ENOMEM;
2867
2868         _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
2869         if (!_new_mapping_cache)
2870                 goto bad_new_mapping_cache;
2871
2872         return 0;
2873
2874 bad_new_mapping_cache:
2875         dm_unregister_target(&pool_target);
2876 bad_pool_target:
2877         dm_unregister_target(&thin_target);
2878
2879         return r;
2880 }
2881
2882 static void dm_thin_exit(void)
2883 {
2884         dm_unregister_target(&thin_target);
2885         dm_unregister_target(&pool_target);
2886
2887         kmem_cache_destroy(_new_mapping_cache);
2888 }
2889
2890 module_init(dm_thin_init);
2891 module_exit(dm_thin_exit);
2892
2893 MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
2894 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2895 MODULE_LICENSE("GPL");