linux/drivers/md/dm-thin-metadata.c
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   1/*
   2 * Copyright (C) 2011-2012 Red Hat, Inc.
   3 *
   4 * This file is released under the GPL.
   5 */
   6
   7#include "dm-thin-metadata.h"
   8#include "persistent-data/dm-btree.h"
   9#include "persistent-data/dm-space-map.h"
  10#include "persistent-data/dm-space-map-disk.h"
  11#include "persistent-data/dm-transaction-manager.h"
  12
  13#include <linux/list.h>
  14#include <linux/device-mapper.h>
  15#include <linux/workqueue.h>
  16
  17/*--------------------------------------------------------------------------
  18 * As far as the metadata goes, there is:
  19 *
  20 * - A superblock in block zero, taking up fewer than 512 bytes for
  21 *   atomic writes.
  22 *
  23 * - A space map managing the metadata blocks.
  24 *
  25 * - A space map managing the data blocks.
  26 *
  27 * - A btree mapping our internal thin dev ids onto struct disk_device_details.
  28 *
  29 * - A hierarchical btree, with 2 levels which effectively maps (thin
  30 *   dev id, virtual block) -> block_time.  Block time is a 64-bit
  31 *   field holding the time in the low 24 bits, and block in the top 48
  32 *   bits.
  33 *
  34 * BTrees consist solely of btree_nodes, that fill a block.  Some are
  35 * internal nodes, as such their values are a __le64 pointing to other
  36 * nodes.  Leaf nodes can store data of any reasonable size (ie. much
  37 * smaller than the block size).  The nodes consist of the header,
  38 * followed by an array of keys, followed by an array of values.  We have
  39 * to binary search on the keys so they're all held together to help the
  40 * cpu cache.
  41 *
  42 * Space maps have 2 btrees:
  43 *
  44 * - One maps a uint64_t onto a struct index_entry.  Which points to a
  45 *   bitmap block, and has some details about how many free entries there
  46 *   are etc.
  47 *
  48 * - The bitmap blocks have a header (for the checksum).  Then the rest
  49 *   of the block is pairs of bits.  With the meaning being:
  50 *
  51 *   0 - ref count is 0
  52 *   1 - ref count is 1
  53 *   2 - ref count is 2
  54 *   3 - ref count is higher than 2
  55 *
  56 * - If the count is higher than 2 then the ref count is entered in a
  57 *   second btree that directly maps the block_address to a uint32_t ref
  58 *   count.
  59 *
  60 * The space map metadata variant doesn't have a bitmaps btree.  Instead
  61 * it has one single blocks worth of index_entries.  This avoids
  62 * recursive issues with the bitmap btree needing to allocate space in
  63 * order to insert.  With a small data block size such as 64k the
  64 * metadata support data devices that are hundreds of terrabytes.
  65 *
  66 * The space maps allocate space linearly from front to back.  Space that
  67 * is freed in a transaction is never recycled within that transaction.
  68 * To try and avoid fragmenting _free_ space the allocator always goes
  69 * back and fills in gaps.
  70 *
  71 * All metadata io is in THIN_METADATA_BLOCK_SIZE sized/aligned chunks
  72 * from the block manager.
  73 *--------------------------------------------------------------------------*/
  74
  75#define DM_MSG_PREFIX   "thin metadata"
  76
  77#define THIN_SUPERBLOCK_MAGIC 27022010
  78#define THIN_SUPERBLOCK_LOCATION 0
  79#define THIN_VERSION 2
  80#define SECTOR_TO_BLOCK_SHIFT 3
  81
  82/*
  83 * For btree insert:
  84 *  3 for btree insert +
  85 *  2 for btree lookup used within space map
  86 * For btree remove:
  87 *  2 for shadow spine +
  88 *  4 for rebalance 3 child node
  89 */
  90#define THIN_MAX_CONCURRENT_LOCKS 6
  91
  92/* This should be plenty */
  93#define SPACE_MAP_ROOT_SIZE 128
  94
  95/*
  96 * Little endian on-disk superblock and device details.
  97 */
  98struct thin_disk_superblock {
  99        __le32 csum;    /* Checksum of superblock except for this field. */
 100        __le32 flags;
 101        __le64 blocknr; /* This block number, dm_block_t. */
 102
 103        __u8 uuid[16];
 104        __le64 magic;
 105        __le32 version;
 106        __le32 time;
 107
 108        __le64 trans_id;
 109
 110        /*
 111         * Root held by userspace transactions.
 112         */
 113        __le64 held_root;
 114
 115        __u8 data_space_map_root[SPACE_MAP_ROOT_SIZE];
 116        __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
 117
 118        /*
 119         * 2-level btree mapping (dev_id, (dev block, time)) -> data block
 120         */
 121        __le64 data_mapping_root;
 122
 123        /*
 124         * Device detail root mapping dev_id -> device_details
 125         */
 126        __le64 device_details_root;
 127
 128        __le32 data_block_size;         /* In 512-byte sectors. */
 129
 130        __le32 metadata_block_size;     /* In 512-byte sectors. */
 131        __le64 metadata_nr_blocks;
 132
 133        __le32 compat_flags;
 134        __le32 compat_ro_flags;
 135        __le32 incompat_flags;
 136} __packed;
 137
 138struct disk_device_details {
 139        __le64 mapped_blocks;
 140        __le64 transaction_id;          /* When created. */
 141        __le32 creation_time;
 142        __le32 snapshotted_time;
 143} __packed;
 144
 145struct dm_pool_metadata {
 146        struct hlist_node hash;
 147
 148        struct block_device *bdev;
 149        struct dm_block_manager *bm;
 150        struct dm_space_map *metadata_sm;
 151        struct dm_space_map *data_sm;
 152        struct dm_transaction_manager *tm;
 153        struct dm_transaction_manager *nb_tm;
 154
 155        /*
 156         * Two-level btree.
 157         * First level holds thin_dev_t.
 158         * Second level holds mappings.
 159         */
 160        struct dm_btree_info info;
 161
 162        /*
 163         * Non-blocking version of the above.
 164         */
 165        struct dm_btree_info nb_info;
 166
 167        /*
 168         * Just the top level for deleting whole devices.
 169         */
 170        struct dm_btree_info tl_info;
 171
 172        /*
 173         * Just the bottom level for creating new devices.
 174         */
 175        struct dm_btree_info bl_info;
 176
 177        /*
 178         * Describes the device details btree.
 179         */
 180        struct dm_btree_info details_info;
 181
 182        struct rw_semaphore root_lock;
 183        uint32_t time;
 184        dm_block_t root;
 185        dm_block_t details_root;
 186        struct list_head thin_devices;
 187        uint64_t trans_id;
 188        unsigned long flags;
 189        sector_t data_block_size;
 190
 191        /*
 192         * We reserve a section of the metadata for commit overhead.
 193         * All reported space does *not* include this.
 194         */
 195        dm_block_t metadata_reserve;
 196
 197        /*
 198         * Set if a transaction has to be aborted but the attempt to roll back
 199         * to the previous (good) transaction failed.  The only pool metadata
 200         * operation possible in this state is the closing of the device.
 201         */
 202        bool fail_io:1;
 203
 204        /*
 205         * Set once a thin-pool has been accessed through one of the interfaces
 206         * that imply the pool is in-service (e.g. thin devices created/deleted,
 207         * thin-pool message, metadata snapshots, etc).
 208         */
 209        bool in_service:1;
 210
 211        /*
 212         * Reading the space map roots can fail, so we read it into these
 213         * buffers before the superblock is locked and updated.
 214         */
 215        __u8 data_space_map_root[SPACE_MAP_ROOT_SIZE];
 216        __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
 217};
 218
 219struct dm_thin_device {
 220        struct list_head list;
 221        struct dm_pool_metadata *pmd;
 222        dm_thin_id id;
 223
 224        int open_count;
 225        bool changed:1;
 226        bool aborted_with_changes:1;
 227        uint64_t mapped_blocks;
 228        uint64_t transaction_id;
 229        uint32_t creation_time;
 230        uint32_t snapshotted_time;
 231};
 232
 233/*----------------------------------------------------------------
 234 * superblock validator
 235 *--------------------------------------------------------------*/
 236
 237#define SUPERBLOCK_CSUM_XOR 160774
 238
 239static void sb_prepare_for_write(struct dm_block_validator *v,
 240                                 struct dm_block *b,
 241                                 size_t block_size)
 242{
 243        struct thin_disk_superblock *disk_super = dm_block_data(b);
 244
 245        disk_super->blocknr = cpu_to_le64(dm_block_location(b));
 246        disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 247                                                      block_size - sizeof(__le32),
 248                                                      SUPERBLOCK_CSUM_XOR));
 249}
 250
 251static int sb_check(struct dm_block_validator *v,
 252                    struct dm_block *b,
 253                    size_t block_size)
 254{
 255        struct thin_disk_superblock *disk_super = dm_block_data(b);
 256        __le32 csum_le;
 257
 258        if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
 259                DMERR("sb_check failed: blocknr %llu: "
 260                      "wanted %llu", le64_to_cpu(disk_super->blocknr),
 261                      (unsigned long long)dm_block_location(b));
 262                return -ENOTBLK;
 263        }
 264
 265        if (le64_to_cpu(disk_super->magic) != THIN_SUPERBLOCK_MAGIC) {
 266                DMERR("sb_check failed: magic %llu: "
 267                      "wanted %llu", le64_to_cpu(disk_super->magic),
 268                      (unsigned long long)THIN_SUPERBLOCK_MAGIC);
 269                return -EILSEQ;
 270        }
 271
 272        csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 273                                             block_size - sizeof(__le32),
 274                                             SUPERBLOCK_CSUM_XOR));
 275        if (csum_le != disk_super->csum) {
 276                DMERR("sb_check failed: csum %u: wanted %u",
 277                      le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
 278                return -EILSEQ;
 279        }
 280
 281        return 0;
 282}
 283
 284static struct dm_block_validator sb_validator = {
 285        .name = "superblock",
 286        .prepare_for_write = sb_prepare_for_write,
 287        .check = sb_check
 288};
 289
 290/*----------------------------------------------------------------
 291 * Methods for the btree value types
 292 *--------------------------------------------------------------*/
 293
 294static uint64_t pack_block_time(dm_block_t b, uint32_t t)
 295{
 296        return (b << 24) | t;
 297}
 298
 299static void unpack_block_time(uint64_t v, dm_block_t *b, uint32_t *t)
 300{
 301        *b = v >> 24;
 302        *t = v & ((1 << 24) - 1);
 303}
 304
 305static void data_block_inc(void *context, const void *value_le)
 306{
 307        struct dm_space_map *sm = context;
 308        __le64 v_le;
 309        uint64_t b;
 310        uint32_t t;
 311
 312        memcpy(&v_le, value_le, sizeof(v_le));
 313        unpack_block_time(le64_to_cpu(v_le), &b, &t);
 314        dm_sm_inc_block(sm, b);
 315}
 316
 317static void data_block_dec(void *context, const void *value_le)
 318{
 319        struct dm_space_map *sm = context;
 320        __le64 v_le;
 321        uint64_t b;
 322        uint32_t t;
 323
 324        memcpy(&v_le, value_le, sizeof(v_le));
 325        unpack_block_time(le64_to_cpu(v_le), &b, &t);
 326        dm_sm_dec_block(sm, b);
 327}
 328
 329static int data_block_equal(void *context, const void *value1_le, const void *value2_le)
 330{
 331        __le64 v1_le, v2_le;
 332        uint64_t b1, b2;
 333        uint32_t t;
 334
 335        memcpy(&v1_le, value1_le, sizeof(v1_le));
 336        memcpy(&v2_le, value2_le, sizeof(v2_le));
 337        unpack_block_time(le64_to_cpu(v1_le), &b1, &t);
 338        unpack_block_time(le64_to_cpu(v2_le), &b2, &t);
 339
 340        return b1 == b2;
 341}
 342
 343static void subtree_inc(void *context, const void *value)
 344{
 345        struct dm_btree_info *info = context;
 346        __le64 root_le;
 347        uint64_t root;
 348
 349        memcpy(&root_le, value, sizeof(root_le));
 350        root = le64_to_cpu(root_le);
 351        dm_tm_inc(info->tm, root);
 352}
 353
 354static void subtree_dec(void *context, const void *value)
 355{
 356        struct dm_btree_info *info = context;
 357        __le64 root_le;
 358        uint64_t root;
 359
 360        memcpy(&root_le, value, sizeof(root_le));
 361        root = le64_to_cpu(root_le);
 362        if (dm_btree_del(info, root))
 363                DMERR("btree delete failed");
 364}
 365
 366static int subtree_equal(void *context, const void *value1_le, const void *value2_le)
 367{
 368        __le64 v1_le, v2_le;
 369        memcpy(&v1_le, value1_le, sizeof(v1_le));
 370        memcpy(&v2_le, value2_le, sizeof(v2_le));
 371
 372        return v1_le == v2_le;
 373}
 374
 375/*----------------------------------------------------------------*/
 376
 377/*
 378 * Variant that is used for in-core only changes or code that
 379 * shouldn't put the pool in service on its own (e.g. commit).
 380 */
 381static inline void __pmd_write_lock(struct dm_pool_metadata *pmd)
 382        __acquires(pmd->root_lock)
 383{
 384        down_write(&pmd->root_lock);
 385}
 386#define pmd_write_lock_in_core(pmd) __pmd_write_lock((pmd))
 387
 388static inline void pmd_write_lock(struct dm_pool_metadata *pmd)
 389{
 390        __pmd_write_lock(pmd);
 391        if (unlikely(!pmd->in_service))
 392                pmd->in_service = true;
 393}
 394
 395static inline void pmd_write_unlock(struct dm_pool_metadata *pmd)
 396        __releases(pmd->root_lock)
 397{
 398        up_write(&pmd->root_lock);
 399}
 400
 401/*----------------------------------------------------------------*/
 402
 403static int superblock_lock_zero(struct dm_pool_metadata *pmd,
 404                                struct dm_block **sblock)
 405{
 406        return dm_bm_write_lock_zero(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 407                                     &sb_validator, sblock);
 408}
 409
 410static int superblock_lock(struct dm_pool_metadata *pmd,
 411                           struct dm_block **sblock)
 412{
 413        return dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 414                                &sb_validator, sblock);
 415}
 416
 417static int __superblock_all_zeroes(struct dm_block_manager *bm, int *result)
 418{
 419        int r;
 420        unsigned i;
 421        struct dm_block *b;
 422        __le64 *data_le, zero = cpu_to_le64(0);
 423        unsigned block_size = dm_bm_block_size(bm) / sizeof(__le64);
 424
 425        /*
 426         * We can't use a validator here - it may be all zeroes.
 427         */
 428        r = dm_bm_read_lock(bm, THIN_SUPERBLOCK_LOCATION, NULL, &b);
 429        if (r)
 430                return r;
 431
 432        data_le = dm_block_data(b);
 433        *result = 1;
 434        for (i = 0; i < block_size; i++) {
 435                if (data_le[i] != zero) {
 436                        *result = 0;
 437                        break;
 438                }
 439        }
 440
 441        dm_bm_unlock(b);
 442
 443        return 0;
 444}
 445
 446static void __setup_btree_details(struct dm_pool_metadata *pmd)
 447{
 448        pmd->info.tm = pmd->tm;
 449        pmd->info.levels = 2;
 450        pmd->info.value_type.context = pmd->data_sm;
 451        pmd->info.value_type.size = sizeof(__le64);
 452        pmd->info.value_type.inc = data_block_inc;
 453        pmd->info.value_type.dec = data_block_dec;
 454        pmd->info.value_type.equal = data_block_equal;
 455
 456        memcpy(&pmd->nb_info, &pmd->info, sizeof(pmd->nb_info));
 457        pmd->nb_info.tm = pmd->nb_tm;
 458
 459        pmd->tl_info.tm = pmd->tm;
 460        pmd->tl_info.levels = 1;
 461        pmd->tl_info.value_type.context = &pmd->bl_info;
 462        pmd->tl_info.value_type.size = sizeof(__le64);
 463        pmd->tl_info.value_type.inc = subtree_inc;
 464        pmd->tl_info.value_type.dec = subtree_dec;
 465        pmd->tl_info.value_type.equal = subtree_equal;
 466
 467        pmd->bl_info.tm = pmd->tm;
 468        pmd->bl_info.levels = 1;
 469        pmd->bl_info.value_type.context = pmd->data_sm;
 470        pmd->bl_info.value_type.size = sizeof(__le64);
 471        pmd->bl_info.value_type.inc = data_block_inc;
 472        pmd->bl_info.value_type.dec = data_block_dec;
 473        pmd->bl_info.value_type.equal = data_block_equal;
 474
 475        pmd->details_info.tm = pmd->tm;
 476        pmd->details_info.levels = 1;
 477        pmd->details_info.value_type.context = NULL;
 478        pmd->details_info.value_type.size = sizeof(struct disk_device_details);
 479        pmd->details_info.value_type.inc = NULL;
 480        pmd->details_info.value_type.dec = NULL;
 481        pmd->details_info.value_type.equal = NULL;
 482}
 483
 484static int save_sm_roots(struct dm_pool_metadata *pmd)
 485{
 486        int r;
 487        size_t len;
 488
 489        r = dm_sm_root_size(pmd->metadata_sm, &len);
 490        if (r < 0)
 491                return r;
 492
 493        r = dm_sm_copy_root(pmd->metadata_sm, &pmd->metadata_space_map_root, len);
 494        if (r < 0)
 495                return r;
 496
 497        r = dm_sm_root_size(pmd->data_sm, &len);
 498        if (r < 0)
 499                return r;
 500
 501        return dm_sm_copy_root(pmd->data_sm, &pmd->data_space_map_root, len);
 502}
 503
 504static void copy_sm_roots(struct dm_pool_metadata *pmd,
 505                          struct thin_disk_superblock *disk)
 506{
 507        memcpy(&disk->metadata_space_map_root,
 508               &pmd->metadata_space_map_root,
 509               sizeof(pmd->metadata_space_map_root));
 510
 511        memcpy(&disk->data_space_map_root,
 512               &pmd->data_space_map_root,
 513               sizeof(pmd->data_space_map_root));
 514}
 515
 516static int __write_initial_superblock(struct dm_pool_metadata *pmd)
 517{
 518        int r;
 519        struct dm_block *sblock;
 520        struct thin_disk_superblock *disk_super;
 521        sector_t bdev_size = i_size_read(pmd->bdev->bd_inode) >> SECTOR_SHIFT;
 522
 523        if (bdev_size > THIN_METADATA_MAX_SECTORS)
 524                bdev_size = THIN_METADATA_MAX_SECTORS;
 525
 526        r = dm_sm_commit(pmd->data_sm);
 527        if (r < 0)
 528                return r;
 529
 530        r = dm_tm_pre_commit(pmd->tm);
 531        if (r < 0)
 532                return r;
 533
 534        r = save_sm_roots(pmd);
 535        if (r < 0)
 536                return r;
 537
 538        r = superblock_lock_zero(pmd, &sblock);
 539        if (r)
 540                return r;
 541
 542        disk_super = dm_block_data(sblock);
 543        disk_super->flags = 0;
 544        memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
 545        disk_super->magic = cpu_to_le64(THIN_SUPERBLOCK_MAGIC);
 546        disk_super->version = cpu_to_le32(THIN_VERSION);
 547        disk_super->time = 0;
 548        disk_super->trans_id = 0;
 549        disk_super->held_root = 0;
 550
 551        copy_sm_roots(pmd, disk_super);
 552
 553        disk_super->data_mapping_root = cpu_to_le64(pmd->root);
 554        disk_super->device_details_root = cpu_to_le64(pmd->details_root);
 555        disk_super->metadata_block_size = cpu_to_le32(THIN_METADATA_BLOCK_SIZE);
 556        disk_super->metadata_nr_blocks = cpu_to_le64(bdev_size >> SECTOR_TO_BLOCK_SHIFT);
 557        disk_super->data_block_size = cpu_to_le32(pmd->data_block_size);
 558
 559        return dm_tm_commit(pmd->tm, sblock);
 560}
 561
 562static int __format_metadata(struct dm_pool_metadata *pmd)
 563{
 564        int r;
 565
 566        r = dm_tm_create_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 567                                 &pmd->tm, &pmd->metadata_sm);
 568        if (r < 0) {
 569                DMERR("tm_create_with_sm failed");
 570                return r;
 571        }
 572
 573        pmd->data_sm = dm_sm_disk_create(pmd->tm, 0);
 574        if (IS_ERR(pmd->data_sm)) {
 575                DMERR("sm_disk_create failed");
 576                r = PTR_ERR(pmd->data_sm);
 577                goto bad_cleanup_tm;
 578        }
 579
 580        pmd->nb_tm = dm_tm_create_non_blocking_clone(pmd->tm);
 581        if (!pmd->nb_tm) {
 582                DMERR("could not create non-blocking clone tm");
 583                r = -ENOMEM;
 584                goto bad_cleanup_data_sm;
 585        }
 586
 587        __setup_btree_details(pmd);
 588
 589        r = dm_btree_empty(&pmd->info, &pmd->root);
 590        if (r < 0)
 591                goto bad_cleanup_nb_tm;
 592
 593        r = dm_btree_empty(&pmd->details_info, &pmd->details_root);
 594        if (r < 0) {
 595                DMERR("couldn't create devices root");
 596                goto bad_cleanup_nb_tm;
 597        }
 598
 599        r = __write_initial_superblock(pmd);
 600        if (r)
 601                goto bad_cleanup_nb_tm;
 602
 603        return 0;
 604
 605bad_cleanup_nb_tm:
 606        dm_tm_destroy(pmd->nb_tm);
 607bad_cleanup_data_sm:
 608        dm_sm_destroy(pmd->data_sm);
 609bad_cleanup_tm:
 610        dm_tm_destroy(pmd->tm);
 611        dm_sm_destroy(pmd->metadata_sm);
 612
 613        return r;
 614}
 615
 616static int __check_incompat_features(struct thin_disk_superblock *disk_super,
 617                                     struct dm_pool_metadata *pmd)
 618{
 619        uint32_t features;
 620
 621        features = le32_to_cpu(disk_super->incompat_flags) & ~THIN_FEATURE_INCOMPAT_SUPP;
 622        if (features) {
 623                DMERR("could not access metadata due to unsupported optional features (%lx).",
 624                      (unsigned long)features);
 625                return -EINVAL;
 626        }
 627
 628        /*
 629         * Check for read-only metadata to skip the following RDWR checks.
 630         */
 631        if (get_disk_ro(pmd->bdev->bd_disk))
 632                return 0;
 633
 634        features = le32_to_cpu(disk_super->compat_ro_flags) & ~THIN_FEATURE_COMPAT_RO_SUPP;
 635        if (features) {
 636                DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
 637                      (unsigned long)features);
 638                return -EINVAL;
 639        }
 640
 641        return 0;
 642}
 643
 644static int __open_metadata(struct dm_pool_metadata *pmd)
 645{
 646        int r;
 647        struct dm_block *sblock;
 648        struct thin_disk_superblock *disk_super;
 649
 650        r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 651                            &sb_validator, &sblock);
 652        if (r < 0) {
 653                DMERR("couldn't read superblock");
 654                return r;
 655        }
 656
 657        disk_super = dm_block_data(sblock);
 658
 659        /* Verify the data block size hasn't changed */
 660        if (le32_to_cpu(disk_super->data_block_size) != pmd->data_block_size) {
 661                DMERR("changing the data block size (from %u to %llu) is not supported",
 662                      le32_to_cpu(disk_super->data_block_size),
 663                      (unsigned long long)pmd->data_block_size);
 664                r = -EINVAL;
 665                goto bad_unlock_sblock;
 666        }
 667
 668        r = __check_incompat_features(disk_super, pmd);
 669        if (r < 0)
 670                goto bad_unlock_sblock;
 671
 672        r = dm_tm_open_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 673                               disk_super->metadata_space_map_root,
 674                               sizeof(disk_super->metadata_space_map_root),
 675                               &pmd->tm, &pmd->metadata_sm);
 676        if (r < 0) {
 677                DMERR("tm_open_with_sm failed");
 678                goto bad_unlock_sblock;
 679        }
 680
 681        pmd->data_sm = dm_sm_disk_open(pmd->tm, disk_super->data_space_map_root,
 682                                       sizeof(disk_super->data_space_map_root));
 683        if (IS_ERR(pmd->data_sm)) {
 684                DMERR("sm_disk_open failed");
 685                r = PTR_ERR(pmd->data_sm);
 686                goto bad_cleanup_tm;
 687        }
 688
 689        pmd->nb_tm = dm_tm_create_non_blocking_clone(pmd->tm);
 690        if (!pmd->nb_tm) {
 691                DMERR("could not create non-blocking clone tm");
 692                r = -ENOMEM;
 693                goto bad_cleanup_data_sm;
 694        }
 695
 696        __setup_btree_details(pmd);
 697        dm_bm_unlock(sblock);
 698
 699        return 0;
 700
 701bad_cleanup_data_sm:
 702        dm_sm_destroy(pmd->data_sm);
 703bad_cleanup_tm:
 704        dm_tm_destroy(pmd->tm);
 705        dm_sm_destroy(pmd->metadata_sm);
 706bad_unlock_sblock:
 707        dm_bm_unlock(sblock);
 708
 709        return r;
 710}
 711
 712static int __open_or_format_metadata(struct dm_pool_metadata *pmd, bool format_device)
 713{
 714        int r, unformatted;
 715
 716        r = __superblock_all_zeroes(pmd->bm, &unformatted);
 717        if (r)
 718                return r;
 719
 720        if (unformatted)
 721                return format_device ? __format_metadata(pmd) : -EPERM;
 722
 723        return __open_metadata(pmd);
 724}
 725
 726static int __create_persistent_data_objects(struct dm_pool_metadata *pmd, bool format_device)
 727{
 728        int r;
 729
 730        pmd->bm = dm_block_manager_create(pmd->bdev, THIN_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
 731                                          THIN_MAX_CONCURRENT_LOCKS);
 732        if (IS_ERR(pmd->bm)) {
 733                DMERR("could not create block manager");
 734                return PTR_ERR(pmd->bm);
 735        }
 736
 737        r = __open_or_format_metadata(pmd, format_device);
 738        if (r)
 739                dm_block_manager_destroy(pmd->bm);
 740
 741        return r;
 742}
 743
 744static void __destroy_persistent_data_objects(struct dm_pool_metadata *pmd)
 745{
 746        dm_sm_destroy(pmd->data_sm);
 747        dm_sm_destroy(pmd->metadata_sm);
 748        dm_tm_destroy(pmd->nb_tm);
 749        dm_tm_destroy(pmd->tm);
 750        dm_block_manager_destroy(pmd->bm);
 751}
 752
 753static int __begin_transaction(struct dm_pool_metadata *pmd)
 754{
 755        int r;
 756        struct thin_disk_superblock *disk_super;
 757        struct dm_block *sblock;
 758
 759        /*
 760         * We re-read the superblock every time.  Shouldn't need to do this
 761         * really.
 762         */
 763        r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 764                            &sb_validator, &sblock);
 765        if (r)
 766                return r;
 767
 768        disk_super = dm_block_data(sblock);
 769        pmd->time = le32_to_cpu(disk_super->time);
 770        pmd->root = le64_to_cpu(disk_super->data_mapping_root);
 771        pmd->details_root = le64_to_cpu(disk_super->device_details_root);
 772        pmd->trans_id = le64_to_cpu(disk_super->trans_id);
 773        pmd->flags = le32_to_cpu(disk_super->flags);
 774        pmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
 775
 776        dm_bm_unlock(sblock);
 777        return 0;
 778}
 779
 780static int __write_changed_details(struct dm_pool_metadata *pmd)
 781{
 782        int r;
 783        struct dm_thin_device *td, *tmp;
 784        struct disk_device_details details;
 785        uint64_t key;
 786
 787        list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
 788                if (!td->changed)
 789                        continue;
 790
 791                key = td->id;
 792
 793                details.mapped_blocks = cpu_to_le64(td->mapped_blocks);
 794                details.transaction_id = cpu_to_le64(td->transaction_id);
 795                details.creation_time = cpu_to_le32(td->creation_time);
 796                details.snapshotted_time = cpu_to_le32(td->snapshotted_time);
 797                __dm_bless_for_disk(&details);
 798
 799                r = dm_btree_insert(&pmd->details_info, pmd->details_root,
 800                                    &key, &details, &pmd->details_root);
 801                if (r)
 802                        return r;
 803
 804                if (td->open_count)
 805                        td->changed = 0;
 806                else {
 807                        list_del(&td->list);
 808                        kfree(td);
 809                }
 810        }
 811
 812        return 0;
 813}
 814
 815static int __commit_transaction(struct dm_pool_metadata *pmd)
 816{
 817        int r;
 818        struct thin_disk_superblock *disk_super;
 819        struct dm_block *sblock;
 820
 821        /*
 822         * We need to know if the thin_disk_superblock exceeds a 512-byte sector.
 823         */
 824        BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512);
 825
 826        if (unlikely(!pmd->in_service))
 827                return 0;
 828
 829        r = __write_changed_details(pmd);
 830        if (r < 0)
 831                return r;
 832
 833        r = dm_sm_commit(pmd->data_sm);
 834        if (r < 0)
 835                return r;
 836
 837        r = dm_tm_pre_commit(pmd->tm);
 838        if (r < 0)
 839                return r;
 840
 841        r = save_sm_roots(pmd);
 842        if (r < 0)
 843                return r;
 844
 845        r = superblock_lock(pmd, &sblock);
 846        if (r)
 847                return r;
 848
 849        disk_super = dm_block_data(sblock);
 850        disk_super->time = cpu_to_le32(pmd->time);
 851        disk_super->data_mapping_root = cpu_to_le64(pmd->root);
 852        disk_super->device_details_root = cpu_to_le64(pmd->details_root);
 853        disk_super->trans_id = cpu_to_le64(pmd->trans_id);
 854        disk_super->flags = cpu_to_le32(pmd->flags);
 855
 856        copy_sm_roots(pmd, disk_super);
 857
 858        return dm_tm_commit(pmd->tm, sblock);
 859}
 860
 861static void __set_metadata_reserve(struct dm_pool_metadata *pmd)
 862{
 863        int r;
 864        dm_block_t total;
 865        dm_block_t max_blocks = 4096; /* 16M */
 866
 867        r = dm_sm_get_nr_blocks(pmd->metadata_sm, &total);
 868        if (r) {
 869                DMERR("could not get size of metadata device");
 870                pmd->metadata_reserve = max_blocks;
 871        } else
 872                pmd->metadata_reserve = min(max_blocks, div_u64(total, 10));
 873}
 874
 875struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
 876                                               sector_t data_block_size,
 877                                               bool format_device)
 878{
 879        int r;
 880        struct dm_pool_metadata *pmd;
 881
 882        pmd = kmalloc(sizeof(*pmd), GFP_KERNEL);
 883        if (!pmd) {
 884                DMERR("could not allocate metadata struct");
 885                return ERR_PTR(-ENOMEM);
 886        }
 887
 888        init_rwsem(&pmd->root_lock);
 889        pmd->time = 0;
 890        INIT_LIST_HEAD(&pmd->thin_devices);
 891        pmd->fail_io = false;
 892        pmd->in_service = false;
 893        pmd->bdev = bdev;
 894        pmd->data_block_size = data_block_size;
 895
 896        r = __create_persistent_data_objects(pmd, format_device);
 897        if (r) {
 898                kfree(pmd);
 899                return ERR_PTR(r);
 900        }
 901
 902        r = __begin_transaction(pmd);
 903        if (r < 0) {
 904                if (dm_pool_metadata_close(pmd) < 0)
 905                        DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
 906                return ERR_PTR(r);
 907        }
 908
 909        __set_metadata_reserve(pmd);
 910
 911        return pmd;
 912}
 913
 914int dm_pool_metadata_close(struct dm_pool_metadata *pmd)
 915{
 916        int r;
 917        unsigned open_devices = 0;
 918        struct dm_thin_device *td, *tmp;
 919
 920        down_read(&pmd->root_lock);
 921        list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
 922                if (td->open_count)
 923                        open_devices++;
 924                else {
 925                        list_del(&td->list);
 926                        kfree(td);
 927                }
 928        }
 929        up_read(&pmd->root_lock);
 930
 931        if (open_devices) {
 932                DMERR("attempt to close pmd when %u device(s) are still open",
 933                       open_devices);
 934                return -EBUSY;
 935        }
 936
 937        if (!dm_bm_is_read_only(pmd->bm) && !pmd->fail_io) {
 938                r = __commit_transaction(pmd);
 939                if (r < 0)
 940                        DMWARN("%s: __commit_transaction() failed, error = %d",
 941                               __func__, r);
 942        }
 943        if (!pmd->fail_io)
 944                __destroy_persistent_data_objects(pmd);
 945
 946        kfree(pmd);
 947        return 0;
 948}
 949
 950/*
 951 * __open_device: Returns @td corresponding to device with id @dev,
 952 * creating it if @create is set and incrementing @td->open_count.
 953 * On failure, @td is undefined.
 954 */
 955static int __open_device(struct dm_pool_metadata *pmd,
 956                         dm_thin_id dev, int create,
 957                         struct dm_thin_device **td)
 958{
 959        int r, changed = 0;
 960        struct dm_thin_device *td2;
 961        uint64_t key = dev;
 962        struct disk_device_details details_le;
 963
 964        /*
 965         * If the device is already open, return it.
 966         */
 967        list_for_each_entry(td2, &pmd->thin_devices, list)
 968                if (td2->id == dev) {
 969                        /*
 970                         * May not create an already-open device.
 971                         */
 972                        if (create)
 973                                return -EEXIST;
 974
 975                        td2->open_count++;
 976                        *td = td2;
 977                        return 0;
 978                }
 979
 980        /*
 981         * Check the device exists.
 982         */
 983        r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
 984                            &key, &details_le);
 985        if (r) {
 986                if (r != -ENODATA || !create)
 987                        return r;
 988
 989                /*
 990                 * Create new device.
 991                 */
 992                changed = 1;
 993                details_le.mapped_blocks = 0;
 994                details_le.transaction_id = cpu_to_le64(pmd->trans_id);
 995                details_le.creation_time = cpu_to_le32(pmd->time);
 996                details_le.snapshotted_time = cpu_to_le32(pmd->time);
 997        }
 998
 999        *td = kmalloc(sizeof(**td), GFP_NOIO);
1000        if (!*td)
1001                return -ENOMEM;
1002
1003        (*td)->pmd = pmd;
1004        (*td)->id = dev;
1005        (*td)->open_count = 1;
1006        (*td)->changed = changed;
1007        (*td)->aborted_with_changes = false;
1008        (*td)->mapped_blocks = le64_to_cpu(details_le.mapped_blocks);
1009        (*td)->transaction_id = le64_to_cpu(details_le.transaction_id);
1010        (*td)->creation_time = le32_to_cpu(details_le.creation_time);
1011        (*td)->snapshotted_time = le32_to_cpu(details_le.snapshotted_time);
1012
1013        list_add(&(*td)->list, &pmd->thin_devices);
1014
1015        return 0;
1016}
1017
1018static void __close_device(struct dm_thin_device *td)
1019{
1020        --td->open_count;
1021}
1022
1023static int __create_thin(struct dm_pool_metadata *pmd,
1024                         dm_thin_id dev)
1025{
1026        int r;
1027        dm_block_t dev_root;
1028        uint64_t key = dev;
1029        struct disk_device_details details_le;
1030        struct dm_thin_device *td;
1031        __le64 value;
1032
1033        r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
1034                            &key, &details_le);
1035        if (!r)
1036                return -EEXIST;
1037
1038        /*
1039         * Create an empty btree for the mappings.
1040         */
1041        r = dm_btree_empty(&pmd->bl_info, &dev_root);
1042        if (r)
1043                return r;
1044
1045        /*
1046         * Insert it into the main mapping tree.
1047         */
1048        value = cpu_to_le64(dev_root);
1049        __dm_bless_for_disk(&value);
1050        r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
1051        if (r) {
1052                dm_btree_del(&pmd->bl_info, dev_root);
1053                return r;
1054        }
1055
1056        r = __open_device(pmd, dev, 1, &td);
1057        if (r) {
1058                dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1059                dm_btree_del(&pmd->bl_info, dev_root);
1060                return r;
1061        }
1062        __close_device(td);
1063
1064        return r;
1065}
1066
1067int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev)
1068{
1069        int r = -EINVAL;
1070
1071        pmd_write_lock(pmd);
1072        if (!pmd->fail_io)
1073                r = __create_thin(pmd, dev);
1074        pmd_write_unlock(pmd);
1075
1076        return r;
1077}
1078
1079static int __set_snapshot_details(struct dm_pool_metadata *pmd,
1080                                  struct dm_thin_device *snap,
1081                                  dm_thin_id origin, uint32_t time)
1082{
1083        int r;
1084        struct dm_thin_device *td;
1085
1086        r = __open_device(pmd, origin, 0, &td);
1087        if (r)
1088                return r;
1089
1090        td->changed = 1;
1091        td->snapshotted_time = time;
1092
1093        snap->mapped_blocks = td->mapped_blocks;
1094        snap->snapshotted_time = time;
1095        __close_device(td);
1096
1097        return 0;
1098}
1099
1100static int __create_snap(struct dm_pool_metadata *pmd,
1101                         dm_thin_id dev, dm_thin_id origin)
1102{
1103        int r;
1104        dm_block_t origin_root;
1105        uint64_t key = origin, dev_key = dev;
1106        struct dm_thin_device *td;
1107        struct disk_device_details details_le;
1108        __le64 value;
1109
1110        /* check this device is unused */
1111        r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
1112                            &dev_key, &details_le);
1113        if (!r)
1114                return -EEXIST;
1115
1116        /* find the mapping tree for the origin */
1117        r = dm_btree_lookup(&pmd->tl_info, pmd->root, &key, &value);
1118        if (r)
1119                return r;
1120        origin_root = le64_to_cpu(value);
1121
1122        /* clone the origin, an inc will do */
1123        dm_tm_inc(pmd->tm, origin_root);
1124
1125        /* insert into the main mapping tree */
1126        value = cpu_to_le64(origin_root);
1127        __dm_bless_for_disk(&value);
1128        key = dev;
1129        r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
1130        if (r) {
1131                dm_tm_dec(pmd->tm, origin_root);
1132                return r;
1133        }
1134
1135        pmd->time++;
1136
1137        r = __open_device(pmd, dev, 1, &td);
1138        if (r)
1139                goto bad;
1140
1141        r = __set_snapshot_details(pmd, td, origin, pmd->time);
1142        __close_device(td);
1143
1144        if (r)
1145                goto bad;
1146
1147        return 0;
1148
1149bad:
1150        dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1151        dm_btree_remove(&pmd->details_info, pmd->details_root,
1152                        &key, &pmd->details_root);
1153        return r;
1154}
1155
1156int dm_pool_create_snap(struct dm_pool_metadata *pmd,
1157                                 dm_thin_id dev,
1158                                 dm_thin_id origin)
1159{
1160        int r = -EINVAL;
1161
1162        pmd_write_lock(pmd);
1163        if (!pmd->fail_io)
1164                r = __create_snap(pmd, dev, origin);
1165        pmd_write_unlock(pmd);
1166
1167        return r;
1168}
1169
1170static int __delete_device(struct dm_pool_metadata *pmd, dm_thin_id dev)
1171{
1172        int r;
1173        uint64_t key = dev;
1174        struct dm_thin_device *td;
1175
1176        /* TODO: failure should mark the transaction invalid */
1177        r = __open_device(pmd, dev, 0, &td);
1178        if (r)
1179                return r;
1180
1181        if (td->open_count > 1) {
1182                __close_device(td);
1183                return -EBUSY;
1184        }
1185
1186        list_del(&td->list);
1187        kfree(td);
1188        r = dm_btree_remove(&pmd->details_info, pmd->details_root,
1189                            &key, &pmd->details_root);
1190        if (r)
1191                return r;
1192
1193        r = dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1194        if (r)
1195                return r;
1196
1197        return 0;
1198}
1199
1200int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd,
1201                               dm_thin_id dev)
1202{
1203        int r = -EINVAL;
1204
1205        pmd_write_lock(pmd);
1206        if (!pmd->fail_io)
1207                r = __delete_device(pmd, dev);
1208        pmd_write_unlock(pmd);
1209
1210        return r;
1211}
1212
1213int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
1214                                        uint64_t current_id,
1215                                        uint64_t new_id)
1216{
1217        int r = -EINVAL;
1218
1219        pmd_write_lock(pmd);
1220
1221        if (pmd->fail_io)
1222                goto out;
1223
1224        if (pmd->trans_id != current_id) {
1225                DMERR("mismatched transaction id");
1226                goto out;
1227        }
1228
1229        pmd->trans_id = new_id;
1230        r = 0;
1231
1232out:
1233        pmd_write_unlock(pmd);
1234
1235        return r;
1236}
1237
1238int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
1239                                        uint64_t *result)
1240{
1241        int r = -EINVAL;
1242
1243        down_read(&pmd->root_lock);
1244        if (!pmd->fail_io) {
1245                *result = pmd->trans_id;
1246                r = 0;
1247        }
1248        up_read(&pmd->root_lock);
1249
1250        return r;
1251}
1252
1253static int __reserve_metadata_snap(struct dm_pool_metadata *pmd)
1254{
1255        int r, inc;
1256        struct thin_disk_superblock *disk_super;
1257        struct dm_block *copy, *sblock;
1258        dm_block_t held_root;
1259
1260        /*
1261         * We commit to ensure the btree roots which we increment in a
1262         * moment are up to date.
1263         */
1264        r = __commit_transaction(pmd);
1265        if (r < 0) {
1266                DMWARN("%s: __commit_transaction() failed, error = %d",
1267                       __func__, r);
1268                return r;
1269        }
1270
1271        /*
1272         * Copy the superblock.
1273         */
1274        dm_sm_inc_block(pmd->metadata_sm, THIN_SUPERBLOCK_LOCATION);
1275        r = dm_tm_shadow_block(pmd->tm, THIN_SUPERBLOCK_LOCATION,
1276                               &sb_validator, &copy, &inc);
1277        if (r)
1278                return r;
1279
1280        BUG_ON(!inc);
1281
1282        held_root = dm_block_location(copy);
1283        disk_super = dm_block_data(copy);
1284
1285        if (le64_to_cpu(disk_super->held_root)) {
1286                DMWARN("Pool metadata snapshot already exists: release this before taking another.");
1287
1288                dm_tm_dec(pmd->tm, held_root);
1289                dm_tm_unlock(pmd->tm, copy);
1290                return -EBUSY;
1291        }
1292
1293        /*
1294         * Wipe the spacemap since we're not publishing this.
1295         */
1296        memset(&disk_super->data_space_map_root, 0,
1297               sizeof(disk_super->data_space_map_root));
1298        memset(&disk_super->metadata_space_map_root, 0,
1299               sizeof(disk_super->metadata_space_map_root));
1300
1301        /*
1302         * Increment the data structures that need to be preserved.
1303         */
1304        dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->data_mapping_root));
1305        dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->device_details_root));
1306        dm_tm_unlock(pmd->tm, copy);
1307
1308        /*
1309         * Write the held root into the superblock.
1310         */
1311        r = superblock_lock(pmd, &sblock);
1312        if (r) {
1313                dm_tm_dec(pmd->tm, held_root);
1314                return r;
1315        }
1316
1317        disk_super = dm_block_data(sblock);
1318        disk_super->held_root = cpu_to_le64(held_root);
1319        dm_bm_unlock(sblock);
1320        return 0;
1321}
1322
1323int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd)
1324{
1325        int r = -EINVAL;
1326
1327        pmd_write_lock(pmd);
1328        if (!pmd->fail_io)
1329                r = __reserve_metadata_snap(pmd);
1330        pmd_write_unlock(pmd);
1331
1332        return r;
1333}
1334
1335static int __release_metadata_snap(struct dm_pool_metadata *pmd)
1336{
1337        int r;
1338        struct thin_disk_superblock *disk_super;
1339        struct dm_block *sblock, *copy;
1340        dm_block_t held_root;
1341
1342        r = superblock_lock(pmd, &sblock);
1343        if (r)
1344                return r;
1345
1346        disk_super = dm_block_data(sblock);
1347        held_root = le64_to_cpu(disk_super->held_root);
1348        disk_super->held_root = cpu_to_le64(0);
1349
1350        dm_bm_unlock(sblock);
1351
1352        if (!held_root) {
1353                DMWARN("No pool metadata snapshot found: nothing to release.");
1354                return -EINVAL;
1355        }
1356
1357        r = dm_tm_read_lock(pmd->tm, held_root, &sb_validator, &copy);
1358        if (r)
1359                return r;
1360
1361        disk_super = dm_block_data(copy);
1362        dm_btree_del(&pmd->info, le64_to_cpu(disk_super->data_mapping_root));
1363        dm_btree_del(&pmd->details_info, le64_to_cpu(disk_super->device_details_root));
1364        dm_sm_dec_block(pmd->metadata_sm, held_root);
1365
1366        dm_tm_unlock(pmd->tm, copy);
1367
1368        return 0;
1369}
1370
1371int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd)
1372{
1373        int r = -EINVAL;
1374
1375        pmd_write_lock(pmd);
1376        if (!pmd->fail_io)
1377                r = __release_metadata_snap(pmd);
1378        pmd_write_unlock(pmd);
1379
1380        return r;
1381}
1382
1383static int __get_metadata_snap(struct dm_pool_metadata *pmd,
1384                               dm_block_t *result)
1385{
1386        int r;
1387        struct thin_disk_superblock *disk_super;
1388        struct dm_block *sblock;
1389
1390        r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
1391                            &sb_validator, &sblock);
1392        if (r)
1393                return r;
1394
1395        disk_super = dm_block_data(sblock);
1396        *result = le64_to_cpu(disk_super->held_root);
1397
1398        dm_bm_unlock(sblock);
1399
1400        return 0;
1401}
1402
1403int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd,
1404                              dm_block_t *result)
1405{
1406        int r = -EINVAL;
1407
1408        down_read(&pmd->root_lock);
1409        if (!pmd->fail_io)
1410                r = __get_metadata_snap(pmd, result);
1411        up_read(&pmd->root_lock);
1412
1413        return r;
1414}
1415
1416int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
1417                             struct dm_thin_device **td)
1418{
1419        int r = -EINVAL;
1420
1421        pmd_write_lock_in_core(pmd);
1422        if (!pmd->fail_io)
1423                r = __open_device(pmd, dev, 0, td);
1424        pmd_write_unlock(pmd);
1425
1426        return r;
1427}
1428
1429int dm_pool_close_thin_device(struct dm_thin_device *td)
1430{
1431        pmd_write_lock_in_core(td->pmd);
1432        __close_device(td);
1433        pmd_write_unlock(td->pmd);
1434
1435        return 0;
1436}
1437
1438dm_thin_id dm_thin_dev_id(struct dm_thin_device *td)
1439{
1440        return td->id;
1441}
1442
1443/*
1444 * Check whether @time (of block creation) is older than @td's last snapshot.
1445 * If so then the associated block is shared with the last snapshot device.
1446 * Any block on a device created *after* the device last got snapshotted is
1447 * necessarily not shared.
1448 */
1449static bool __snapshotted_since(struct dm_thin_device *td, uint32_t time)
1450{
1451        return td->snapshotted_time > time;
1452}
1453
1454static void unpack_lookup_result(struct dm_thin_device *td, __le64 value,
1455                                 struct dm_thin_lookup_result *result)
1456{
1457        uint64_t block_time = 0;
1458        dm_block_t exception_block;
1459        uint32_t exception_time;
1460
1461        block_time = le64_to_cpu(value);
1462        unpack_block_time(block_time, &exception_block, &exception_time);
1463        result->block = exception_block;
1464        result->shared = __snapshotted_since(td, exception_time);
1465}
1466
1467static int __find_block(struct dm_thin_device *td, dm_block_t block,
1468                        int can_issue_io, struct dm_thin_lookup_result *result)
1469{
1470        int r;
1471        __le64 value;
1472        struct dm_pool_metadata *pmd = td->pmd;
1473        dm_block_t keys[2] = { td->id, block };
1474        struct dm_btree_info *info;
1475
1476        if (can_issue_io) {
1477                info = &pmd->info;
1478        } else
1479                info = &pmd->nb_info;
1480
1481        r = dm_btree_lookup(info, pmd->root, keys, &value);
1482        if (!r)
1483                unpack_lookup_result(td, value, result);
1484
1485        return r;
1486}
1487
1488int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
1489                       int can_issue_io, struct dm_thin_lookup_result *result)
1490{
1491        int r;
1492        struct dm_pool_metadata *pmd = td->pmd;
1493
1494        down_read(&pmd->root_lock);
1495        if (pmd->fail_io) {
1496                up_read(&pmd->root_lock);
1497                return -EINVAL;
1498        }
1499
1500        r = __find_block(td, block, can_issue_io, result);
1501
1502        up_read(&pmd->root_lock);
1503        return r;
1504}
1505
1506static int __find_next_mapped_block(struct dm_thin_device *td, dm_block_t block,
1507                                          dm_block_t *vblock,
1508                                          struct dm_thin_lookup_result *result)
1509{
1510        int r;
1511        __le64 value;
1512        struct dm_pool_metadata *pmd = td->pmd;
1513        dm_block_t keys[2] = { td->id, block };
1514
1515        r = dm_btree_lookup_next(&pmd->info, pmd->root, keys, vblock, &value);
1516        if (!r)
1517                unpack_lookup_result(td, value, result);
1518
1519        return r;
1520}
1521
1522static int __find_mapped_range(struct dm_thin_device *td,
1523                               dm_block_t begin, dm_block_t end,
1524                               dm_block_t *thin_begin, dm_block_t *thin_end,
1525                               dm_block_t *pool_begin, bool *maybe_shared)
1526{
1527        int r;
1528        dm_block_t pool_end;
1529        struct dm_thin_lookup_result lookup;
1530
1531        if (end < begin)
1532                return -ENODATA;
1533
1534        r = __find_next_mapped_block(td, begin, &begin, &lookup);
1535        if (r)
1536                return r;
1537
1538        if (begin >= end)
1539                return -ENODATA;
1540
1541        *thin_begin = begin;
1542        *pool_begin = lookup.block;
1543        *maybe_shared = lookup.shared;
1544
1545        begin++;
1546        pool_end = *pool_begin + 1;
1547        while (begin != end) {
1548                r = __find_block(td, begin, true, &lookup);
1549                if (r) {
1550                        if (r == -ENODATA)
1551                                break;
1552                        else
1553                                return r;
1554                }
1555
1556                if ((lookup.block != pool_end) ||
1557                    (lookup.shared != *maybe_shared))
1558                        break;
1559
1560                pool_end++;
1561                begin++;
1562        }
1563
1564        *thin_end = begin;
1565        return 0;
1566}
1567
1568int dm_thin_find_mapped_range(struct dm_thin_device *td,
1569                              dm_block_t begin, dm_block_t end,
1570                              dm_block_t *thin_begin, dm_block_t *thin_end,
1571                              dm_block_t *pool_begin, bool *maybe_shared)
1572{
1573        int r = -EINVAL;
1574        struct dm_pool_metadata *pmd = td->pmd;
1575
1576        down_read(&pmd->root_lock);
1577        if (!pmd->fail_io) {
1578                r = __find_mapped_range(td, begin, end, thin_begin, thin_end,
1579                                        pool_begin, maybe_shared);
1580        }
1581        up_read(&pmd->root_lock);
1582
1583        return r;
1584}
1585
1586static int __insert(struct dm_thin_device *td, dm_block_t block,
1587                    dm_block_t data_block)
1588{
1589        int r, inserted;
1590        __le64 value;
1591        struct dm_pool_metadata *pmd = td->pmd;
1592        dm_block_t keys[2] = { td->id, block };
1593
1594        value = cpu_to_le64(pack_block_time(data_block, pmd->time));
1595        __dm_bless_for_disk(&value);
1596
1597        r = dm_btree_insert_notify(&pmd->info, pmd->root, keys, &value,
1598                                   &pmd->root, &inserted);
1599        if (r)
1600                return r;
1601
1602        td->changed = 1;
1603        if (inserted)
1604                td->mapped_blocks++;
1605
1606        return 0;
1607}
1608
1609int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
1610                         dm_block_t data_block)
1611{
1612        int r = -EINVAL;
1613
1614        pmd_write_lock(td->pmd);
1615        if (!td->pmd->fail_io)
1616                r = __insert(td, block, data_block);
1617        pmd_write_unlock(td->pmd);
1618
1619        return r;
1620}
1621
1622static int __remove(struct dm_thin_device *td, dm_block_t block)
1623{
1624        int r;
1625        struct dm_pool_metadata *pmd = td->pmd;
1626        dm_block_t keys[2] = { td->id, block };
1627
1628        r = dm_btree_remove(&pmd->info, pmd->root, keys, &pmd->root);
1629        if (r)
1630                return r;
1631
1632        td->mapped_blocks--;
1633        td->changed = 1;
1634
1635        return 0;
1636}
1637
1638static int __remove_range(struct dm_thin_device *td, dm_block_t begin, dm_block_t end)
1639{
1640        int r;
1641        unsigned count, total_count = 0;
1642        struct dm_pool_metadata *pmd = td->pmd;
1643        dm_block_t keys[1] = { td->id };
1644        __le64 value;
1645        dm_block_t mapping_root;
1646
1647        /*
1648         * Find the mapping tree
1649         */
1650        r = dm_btree_lookup(&pmd->tl_info, pmd->root, keys, &value);
1651        if (r)
1652                return r;
1653
1654        /*
1655         * Remove from the mapping tree, taking care to inc the
1656         * ref count so it doesn't get deleted.
1657         */
1658        mapping_root = le64_to_cpu(value);
1659        dm_tm_inc(pmd->tm, mapping_root);
1660        r = dm_btree_remove(&pmd->tl_info, pmd->root, keys, &pmd->root);
1661        if (r)
1662                return r;
1663
1664        /*
1665         * Remove leaves stops at the first unmapped entry, so we have to
1666         * loop round finding mapped ranges.
1667         */
1668        while (begin < end) {
1669                r = dm_btree_lookup_next(&pmd->bl_info, mapping_root, &begin, &begin, &value);
1670                if (r == -ENODATA)
1671                        break;
1672
1673                if (r)
1674                        return r;
1675
1676                if (begin >= end)
1677                        break;
1678
1679                r = dm_btree_remove_leaves(&pmd->bl_info, mapping_root, &begin, end, &mapping_root, &count);
1680                if (r)
1681                        return r;
1682
1683                total_count += count;
1684        }
1685
1686        td->mapped_blocks -= total_count;
1687        td->changed = 1;
1688
1689        /*
1690         * Reinsert the mapping tree.
1691         */
1692        value = cpu_to_le64(mapping_root);
1693        __dm_bless_for_disk(&value);
1694        return dm_btree_insert(&pmd->tl_info, pmd->root, keys, &value, &pmd->root);
1695}
1696
1697int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block)
1698{
1699        int r = -EINVAL;
1700
1701        pmd_write_lock(td->pmd);
1702        if (!td->pmd->fail_io)
1703                r = __remove(td, block);
1704        pmd_write_unlock(td->pmd);
1705
1706        return r;
1707}
1708
1709int dm_thin_remove_range(struct dm_thin_device *td,
1710                         dm_block_t begin, dm_block_t end)
1711{
1712        int r = -EINVAL;
1713
1714        pmd_write_lock(td->pmd);
1715        if (!td->pmd->fail_io)
1716                r = __remove_range(td, begin, end);
1717        pmd_write_unlock(td->pmd);
1718
1719        return r;
1720}
1721
1722int dm_pool_block_is_shared(struct dm_pool_metadata *pmd, dm_block_t b, bool *result)
1723{
1724        int r;
1725        uint32_t ref_count;
1726
1727        down_read(&pmd->root_lock);
1728        r = dm_sm_get_count(pmd->data_sm, b, &ref_count);
1729        if (!r)
1730                *result = (ref_count > 1);
1731        up_read(&pmd->root_lock);
1732
1733        return r;
1734}
1735
1736int dm_pool_inc_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e)
1737{
1738        int r = 0;
1739
1740        pmd_write_lock(pmd);
1741        for (; b != e; b++) {
1742                r = dm_sm_inc_block(pmd->data_sm, b);
1743                if (r)
1744                        break;
1745        }
1746        pmd_write_unlock(pmd);
1747
1748        return r;
1749}
1750
1751int dm_pool_dec_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e)
1752{
1753        int r = 0;
1754
1755        pmd_write_lock(pmd);
1756        for (; b != e; b++) {
1757                r = dm_sm_dec_block(pmd->data_sm, b);
1758                if (r)
1759                        break;
1760        }
1761        pmd_write_unlock(pmd);
1762
1763        return r;
1764}
1765
1766bool dm_thin_changed_this_transaction(struct dm_thin_device *td)
1767{
1768        int r;
1769
1770        down_read(&td->pmd->root_lock);
1771        r = td->changed;
1772        up_read(&td->pmd->root_lock);
1773
1774        return r;
1775}
1776
1777bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd)
1778{
1779        bool r = false;
1780        struct dm_thin_device *td, *tmp;
1781
1782        down_read(&pmd->root_lock);
1783        list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
1784                if (td->changed) {
1785                        r = td->changed;
1786                        break;
1787                }
1788        }
1789        up_read(&pmd->root_lock);
1790
1791        return r;
1792}
1793
1794bool dm_thin_aborted_changes(struct dm_thin_device *td)
1795{
1796        bool r;
1797
1798        down_read(&td->pmd->root_lock);
1799        r = td->aborted_with_changes;
1800        up_read(&td->pmd->root_lock);
1801
1802        return r;
1803}
1804
1805int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result)
1806{
1807        int r = -EINVAL;
1808
1809        pmd_write_lock(pmd);
1810        if (!pmd->fail_io)
1811                r = dm_sm_new_block(pmd->data_sm, result);
1812        pmd_write_unlock(pmd);
1813
1814        return r;
1815}
1816
1817int dm_pool_commit_metadata(struct dm_pool_metadata *pmd)
1818{
1819        int r = -EINVAL;
1820
1821        /*
1822         * Care is taken to not have commit be what
1823         * triggers putting the thin-pool in-service.
1824         */
1825        __pmd_write_lock(pmd);
1826        if (pmd->fail_io)
1827                goto out;
1828
1829        r = __commit_transaction(pmd);
1830        if (r < 0)
1831                goto out;
1832
1833        /*
1834         * Open the next transaction.
1835         */
1836        r = __begin_transaction(pmd);
1837out:
1838        pmd_write_unlock(pmd);
1839        return r;
1840}
1841
1842static void __set_abort_with_changes_flags(struct dm_pool_metadata *pmd)
1843{
1844        struct dm_thin_device *td;
1845
1846        list_for_each_entry(td, &pmd->thin_devices, list)
1847                td->aborted_with_changes = td->changed;
1848}
1849
1850int dm_pool_abort_metadata(struct dm_pool_metadata *pmd)
1851{
1852        int r = -EINVAL;
1853
1854        pmd_write_lock(pmd);
1855        if (pmd->fail_io)
1856                goto out;
1857
1858        __set_abort_with_changes_flags(pmd);
1859        __destroy_persistent_data_objects(pmd);
1860        r = __create_persistent_data_objects(pmd, false);
1861        if (r)
1862                pmd->fail_io = true;
1863
1864out:
1865        pmd_write_unlock(pmd);
1866
1867        return r;
1868}
1869
1870int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, dm_block_t *result)
1871{
1872        int r = -EINVAL;
1873
1874        down_read(&pmd->root_lock);
1875        if (!pmd->fail_io)
1876                r = dm_sm_get_nr_free(pmd->data_sm, result);
1877        up_read(&pmd->root_lock);
1878
1879        return r;
1880}
1881
1882int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
1883                                          dm_block_t *result)
1884{
1885        int r = -EINVAL;
1886
1887        down_read(&pmd->root_lock);
1888        if (!pmd->fail_io)
1889                r = dm_sm_get_nr_free(pmd->metadata_sm, result);
1890
1891        if (!r) {
1892                if (*result < pmd->metadata_reserve)
1893                        *result = 0;
1894                else
1895                        *result -= pmd->metadata_reserve;
1896        }
1897        up_read(&pmd->root_lock);
1898
1899        return r;
1900}
1901
1902int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
1903                                  dm_block_t *result)
1904{
1905        int r = -EINVAL;
1906
1907        down_read(&pmd->root_lock);
1908        if (!pmd->fail_io)
1909                r = dm_sm_get_nr_blocks(pmd->metadata_sm, result);
1910        up_read(&pmd->root_lock);
1911
1912        return r;
1913}
1914
1915int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result)
1916{
1917        int r = -EINVAL;
1918
1919        down_read(&pmd->root_lock);
1920        if (!pmd->fail_io)
1921                r = dm_sm_get_nr_blocks(pmd->data_sm, result);
1922        up_read(&pmd->root_lock);
1923
1924        return r;
1925}
1926
1927int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result)
1928{
1929        int r = -EINVAL;
1930        struct dm_pool_metadata *pmd = td->pmd;
1931
1932        down_read(&pmd->root_lock);
1933        if (!pmd->fail_io) {
1934                *result = td->mapped_blocks;
1935                r = 0;
1936        }
1937        up_read(&pmd->root_lock);
1938
1939        return r;
1940}
1941
1942static int __highest_block(struct dm_thin_device *td, dm_block_t *result)
1943{
1944        int r;
1945        __le64 value_le;
1946        dm_block_t thin_root;
1947        struct dm_pool_metadata *pmd = td->pmd;
1948
1949        r = dm_btree_lookup(&pmd->tl_info, pmd->root, &td->id, &value_le);
1950        if (r)
1951                return r;
1952
1953        thin_root = le64_to_cpu(value_le);
1954
1955        return dm_btree_find_highest_key(&pmd->bl_info, thin_root, result);
1956}
1957
1958int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
1959                                     dm_block_t *result)
1960{
1961        int r = -EINVAL;
1962        struct dm_pool_metadata *pmd = td->pmd;
1963
1964        down_read(&pmd->root_lock);
1965        if (!pmd->fail_io)
1966                r = __highest_block(td, result);
1967        up_read(&pmd->root_lock);
1968
1969        return r;
1970}
1971
1972static int __resize_space_map(struct dm_space_map *sm, dm_block_t new_count)
1973{
1974        int r;
1975        dm_block_t old_count;
1976
1977        r = dm_sm_get_nr_blocks(sm, &old_count);
1978        if (r)
1979                return r;
1980
1981        if (new_count == old_count)
1982                return 0;
1983
1984        if (new_count < old_count) {
1985                DMERR("cannot reduce size of space map");
1986                return -EINVAL;
1987        }
1988
1989        return dm_sm_extend(sm, new_count - old_count);
1990}
1991
1992int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
1993{
1994        int r = -EINVAL;
1995
1996        pmd_write_lock(pmd);
1997        if (!pmd->fail_io)
1998                r = __resize_space_map(pmd->data_sm, new_count);
1999        pmd_write_unlock(pmd);
2000
2001        return r;
2002}
2003
2004int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
2005{
2006        int r = -EINVAL;
2007
2008        pmd_write_lock(pmd);
2009        if (!pmd->fail_io) {
2010                r = __resize_space_map(pmd->metadata_sm, new_count);
2011                if (!r)
2012                        __set_metadata_reserve(pmd);
2013        }
2014        pmd_write_unlock(pmd);
2015
2016        return r;
2017}
2018
2019void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd)
2020{
2021        pmd_write_lock_in_core(pmd);
2022        dm_bm_set_read_only(pmd->bm);
2023        pmd_write_unlock(pmd);
2024}
2025
2026void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd)
2027{
2028        pmd_write_lock_in_core(pmd);
2029        dm_bm_set_read_write(pmd->bm);
2030        pmd_write_unlock(pmd);
2031}
2032
2033int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd,
2034                                        dm_block_t threshold,
2035                                        dm_sm_threshold_fn fn,
2036                                        void *context)
2037{
2038        int r;
2039
2040        pmd_write_lock_in_core(pmd);
2041        r = dm_sm_register_threshold_callback(pmd->metadata_sm, threshold, fn, context);
2042        pmd_write_unlock(pmd);
2043
2044        return r;
2045}
2046
2047int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd)
2048{
2049        int r;
2050        struct dm_block *sblock;
2051        struct thin_disk_superblock *disk_super;
2052
2053        pmd_write_lock(pmd);
2054        pmd->flags |= THIN_METADATA_NEEDS_CHECK_FLAG;
2055
2056        r = superblock_lock(pmd, &sblock);
2057        if (r) {
2058                DMERR("couldn't read superblock");
2059                goto out;
2060        }
2061
2062        disk_super = dm_block_data(sblock);
2063        disk_super->flags = cpu_to_le32(pmd->flags);
2064
2065        dm_bm_unlock(sblock);
2066out:
2067        pmd_write_unlock(pmd);
2068        return r;
2069}
2070
2071bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd)
2072{
2073        bool needs_check;
2074
2075        down_read(&pmd->root_lock);
2076        needs_check = pmd->flags & THIN_METADATA_NEEDS_CHECK_FLAG;
2077        up_read(&pmd->root_lock);
2078
2079        return needs_check;
2080}
2081
2082void dm_pool_issue_prefetches(struct dm_pool_metadata *pmd)
2083{
2084        down_read(&pmd->root_lock);
2085        if (!pmd->fail_io)
2086                dm_tm_issue_prefetches(pmd->tm);
2087        up_read(&pmd->root_lock);
2088}
2089