drivers/md/dm-thin-metadata.c

   1 /*
   2  * Copyright (C) 2011 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 1
  80 #define THIN_METADATA_CACHE_SIZE 64
  81 #define SECTOR_TO_BLOCK_SHIFT 3
  82
  83 /*
  84  *  3 for btree insert +
  85  *  2 for btree lookup used within space map
  86  */
  87 #define THIN_MAX_CONCURRENT_LOCKS 5
  88
  89 /* This should be plenty */
  90 #define SPACE_MAP_ROOT_SIZE 128
  91
  92 /*
  93  * Little endian on-disk superblock and device details.
  94  */
  95 struct thin_disk_superblock {
  96         __le32 csum;    /* Checksum of superblock except for this field. */
  97         __le32 flags;
  98         __le64 blocknr; /* This block number, dm_block_t. */
  99
 100         __u8 uuid[16];
 101         __le64 magic;
 102         __le32 version;
 103         __le32 time;
 104
 105         __le64 trans_id;
 106
 107         /*
 108          * Root held by userspace transactions.
 109          */
 110         __le64 held_root;
 111
 112         __u8 data_space_map_root[SPACE_MAP_ROOT_SIZE];
 113         __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
 114
 115         /*
 116          * 2-level btree mapping (dev_id, (dev block, time)) -> data block
 117          */
 118         __le64 data_mapping_root;
 119
 120         /*
 121          * Device detail root mapping dev_id -> device_details
 122          */
 123         __le64 device_details_root;
 124
 125         __le32 data_block_size;         /* In 512-byte sectors. */
 126
 127         __le32 metadata_block_size;     /* In 512-byte sectors. */
 128         __le64 metadata_nr_blocks;
 129
 130         __le32 compat_flags;
 131         __le32 compat_ro_flags;
 132         __le32 incompat_flags;
 133 } __packed;
 134
 135 struct disk_device_details {
 136         __le64 mapped_blocks;
 137         __le64 transaction_id;          /* When created. */
 138         __le32 creation_time;
 139         __le32 snapshotted_time;
 140 } __packed;
 141
 142 struct dm_pool_metadata {
 143         struct hlist_node hash;
 144
 145         struct block_device *bdev;
 146         struct dm_block_manager *bm;
 147         struct dm_space_map *metadata_sm;
 148         struct dm_space_map *data_sm;
 149         struct dm_transaction_manager *tm;
 150         struct dm_transaction_manager *nb_tm;
 151
 152         /*
 153          * Two-level btree.
 154          * First level holds thin_dev_t.
 155          * Second level holds mappings.
 156          */
 157         struct dm_btree_info info;
 158
 159         /*
 160          * Non-blocking version of the above.
 161          */
 162         struct dm_btree_info nb_info;
 163
 164         /*
 165          * Just the top level for deleting whole devices.
 166          */
 167         struct dm_btree_info tl_info;
 168
 169         /*
 170          * Just the bottom level for creating new devices.
 171          */
 172         struct dm_btree_info bl_info;
 173
 174         /*
 175          * Describes the device details btree.
 176          */
 177         struct dm_btree_info details_info;
 178
 179         struct rw_semaphore root_lock;
 180         uint32_t time;
 181         dm_block_t root;
 182         dm_block_t details_root;
 183         struct list_head thin_devices;
 184         uint64_t trans_id;
 185         unsigned long flags;
 186         sector_t data_block_size;
 187 };
 188
 189 struct dm_thin_device {
 190         struct list_head list;
 191         struct dm_pool_metadata *pmd;
 192         dm_thin_id id;
 193
 194         int open_count;
 195         int changed;
 196         uint64_t mapped_blocks;
 197         uint64_t transaction_id;
 198         uint32_t creation_time;
 199         uint32_t snapshotted_time;
 200 };
 201
 202 /*----------------------------------------------------------------
 203  * superblock validator
 204  *--------------------------------------------------------------*/
 205
 206 #define SUPERBLOCK_CSUM_XOR 160774
 207
 208 static void sb_prepare_for_write(struct dm_block_validator *v,
 209                                  struct dm_block *b,
 210                                  size_t block_size)
 211 {
 212         struct thin_disk_superblock *disk_super = dm_block_data(b);
 213
 214         disk_super->blocknr = cpu_to_le64(dm_block_location(b));
 215         disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 216                                                       block_size - sizeof(__le32),
 217                                                       SUPERBLOCK_CSUM_XOR));
 218 }
 219
 220 static int sb_check(struct dm_block_validator *v,
 221                     struct dm_block *b,
 222                     size_t block_size)
 223 {
 224         struct thin_disk_superblock *disk_super = dm_block_data(b);
 225         __le32 csum_le;
 226
 227         if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
 228                 DMERR("sb_check failed: blocknr %llu: "
 229                       "wanted %llu", le64_to_cpu(disk_super->blocknr),
 230                       (unsigned long long)dm_block_location(b));
 231                 return -ENOTBLK;
 232         }
 233
 234         if (le64_to_cpu(disk_super->magic) != THIN_SUPERBLOCK_MAGIC) {
 235                 DMERR("sb_check failed: magic %llu: "
 236                       "wanted %llu", le64_to_cpu(disk_super->magic),
 237                       (unsigned long long)THIN_SUPERBLOCK_MAGIC);
 238                 return -EILSEQ;
 239         }
 240
 241         csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 242                                              block_size - sizeof(__le32),
 243                                              SUPERBLOCK_CSUM_XOR));
 244         if (csum_le != disk_super->csum) {
 245                 DMERR("sb_check failed: csum %u: wanted %u",
 246                       le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
 247                 return -EILSEQ;
 248         }
 249
 250         return 0;
 251 }
 252
 253 static struct dm_block_validator sb_validator = {
 254         .name = "superblock",
 255         .prepare_for_write = sb_prepare_for_write,
 256         .check = sb_check
 257 };
 258
 259 /*----------------------------------------------------------------
 260  * Methods for the btree value types
 261  *--------------------------------------------------------------*/
 262
 263 static uint64_t pack_block_time(dm_block_t b, uint32_t t)
 264 {
 265         return (b << 24) | t;
 266 }
 267
 268 static void unpack_block_time(uint64_t v, dm_block_t *b, uint32_t *t)
 269 {
 270         *b = v >> 24;
 271         *t = v & ((1 << 24) - 1);
 272 }
 273
 274 static void data_block_inc(void *context, void *value_le)
 275 {
 276         struct dm_space_map *sm = context;
 277         __le64 v_le;
 278         uint64_t b;
 279         uint32_t t;
 280
 281         memcpy(&v_le, value_le, sizeof(v_le));
 282         unpack_block_time(le64_to_cpu(v_le), &b, &t);
 283         dm_sm_inc_block(sm, b);
 284 }
 285
 286 static void data_block_dec(void *context, void *value_le)
 287 {
 288         struct dm_space_map *sm = context;
 289         __le64 v_le;
 290         uint64_t b;
 291         uint32_t t;
 292
 293         memcpy(&v_le, value_le, sizeof(v_le));
 294         unpack_block_time(le64_to_cpu(v_le), &b, &t);
 295         dm_sm_dec_block(sm, b);
 296 }
 297
 298 static int data_block_equal(void *context, void *value1_le, void *value2_le)
 299 {
 300         __le64 v1_le, v2_le;
 301         uint64_t b1, b2;
 302         uint32_t t;
 303
 304         memcpy(&v1_le, value1_le, sizeof(v1_le));
 305         memcpy(&v2_le, value2_le, sizeof(v2_le));
 306         unpack_block_time(le64_to_cpu(v1_le), &b1, &t);
 307         unpack_block_time(le64_to_cpu(v2_le), &b2, &t);
 308
 309         return b1 == b2;
 310 }
 311
 312 static void subtree_inc(void *context, void *value)
 313 {
 314         struct dm_btree_info *info = context;
 315         __le64 root_le;
 316         uint64_t root;
 317
 318         memcpy(&root_le, value, sizeof(root_le));
 319         root = le64_to_cpu(root_le);
 320         dm_tm_inc(info->tm, root);
 321 }
 322
 323 static void subtree_dec(void *context, void *value)
 324 {
 325         struct dm_btree_info *info = context;
 326         __le64 root_le;
 327         uint64_t root;
 328
 329         memcpy(&root_le, value, sizeof(root_le));
 330         root = le64_to_cpu(root_le);
 331         if (dm_btree_del(info, root))
 332                 DMERR("btree delete failed\n");
 333 }
 334
 335 static int subtree_equal(void *context, void *value1_le, void *value2_le)
 336 {
 337         __le64 v1_le, v2_le;
 338         memcpy(&v1_le, value1_le, sizeof(v1_le));
 339         memcpy(&v2_le, value2_le, sizeof(v2_le));
 340
 341         return v1_le == v2_le;
 342 }
 343
 344 /*----------------------------------------------------------------*/
 345
 346 static int superblock_lock_zero(struct dm_pool_metadata *pmd,
 347                                 struct dm_block **sblock)
 348 {
 349         return dm_bm_write_lock_zero(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 350                                      &sb_validator, sblock);
 351 }
 352
 353 static int superblock_lock(struct dm_pool_metadata *pmd,
 354                            struct dm_block **sblock)
 355 {
 356         return dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 357                                 &sb_validator, sblock);
 358 }
 359
 360 static int __superblock_all_zeroes(struct dm_block_manager *bm, int *result)
 361 {
 362         int r;
 363         unsigned i;
 364         struct dm_block *b;
 365         __le64 *data_le, zero = cpu_to_le64(0);
 366         unsigned block_size = dm_bm_block_size(bm) / sizeof(__le64);
 367
 368         /*
 369          * We can't use a validator here - it may be all zeroes.
 370          */
 371         r = dm_bm_read_lock(bm, THIN_SUPERBLOCK_LOCATION, NULL, &b);
 372         if (r)
 373                 return r;
 374
 375         data_le = dm_block_data(b);
 376         *result = 1;
 377         for (i = 0; i < block_size; i++) {
 378                 if (data_le[i] != zero) {
 379                         *result = 0;
 380                         break;
 381                 }
 382         }
 383
 384         return dm_bm_unlock(b);
 385 }
 386
 387 static void __setup_btree_details(struct dm_pool_metadata *pmd)
 388 {
 389         pmd->info.tm = pmd->tm;
 390         pmd->info.levels = 2;
 391         pmd->info.value_type.context = pmd->data_sm;
 392         pmd->info.value_type.size = sizeof(__le64);
 393         pmd->info.value_type.inc = data_block_inc;
 394         pmd->info.value_type.dec = data_block_dec;
 395         pmd->info.value_type.equal = data_block_equal;
 396
 397         memcpy(&pmd->nb_info, &pmd->info, sizeof(pmd->nb_info));
 398         pmd->nb_info.tm = pmd->nb_tm;
 399
 400         pmd->tl_info.tm = pmd->tm;
 401         pmd->tl_info.levels = 1;
 402         pmd->tl_info.value_type.context = &pmd->info;
 403         pmd->tl_info.value_type.size = sizeof(__le64);
 404         pmd->tl_info.value_type.inc = subtree_inc;
 405         pmd->tl_info.value_type.dec = subtree_dec;
 406         pmd->tl_info.value_type.equal = subtree_equal;
 407
 408         pmd->bl_info.tm = pmd->tm;
 409         pmd->bl_info.levels = 1;
 410         pmd->bl_info.value_type.context = pmd->data_sm;
 411         pmd->bl_info.value_type.size = sizeof(__le64);
 412         pmd->bl_info.value_type.inc = data_block_inc;
 413         pmd->bl_info.value_type.dec = data_block_dec;
 414         pmd->bl_info.value_type.equal = data_block_equal;
 415
 416         pmd->details_info.tm = pmd->tm;
 417         pmd->details_info.levels = 1;
 418         pmd->details_info.value_type.context = NULL;
 419         pmd->details_info.value_type.size = sizeof(struct disk_device_details);
 420         pmd->details_info.value_type.inc = NULL;
 421         pmd->details_info.value_type.dec = NULL;
 422         pmd->details_info.value_type.equal = NULL;
 423 }
 424
 425 static int __write_initial_superblock(struct dm_pool_metadata *pmd)
 426 {
 427         int r;
 428         struct dm_block *sblock;
 429         size_t metadata_len, data_len;
 430         struct thin_disk_superblock *disk_super;
 431         sector_t bdev_size = i_size_read(pmd->bdev->bd_inode) >> SECTOR_SHIFT;
 432
 433         if (bdev_size > THIN_METADATA_MAX_SECTORS)
 434                 bdev_size = THIN_METADATA_MAX_SECTORS;
 435
 436         r = dm_sm_root_size(pmd->metadata_sm, &metadata_len);
 437         if (r < 0)
 438                 return r;
 439
 440         r = dm_sm_root_size(pmd->data_sm, &data_len);
 441         if (r < 0)
 442                 return r;
 443
 444         r = dm_sm_commit(pmd->data_sm);
 445         if (r < 0)
 446                 return r;
 447
 448         r = dm_tm_pre_commit(pmd->tm);
 449         if (r < 0)
 450                 return r;
 451
 452         r = superblock_lock_zero(pmd, &sblock);
 453         if (r)
 454                 return r;
 455
 456         disk_super = dm_block_data(sblock);
 457         disk_super->flags = 0;
 458         memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
 459         disk_super->magic = cpu_to_le64(THIN_SUPERBLOCK_MAGIC);
 460         disk_super->version = cpu_to_le32(THIN_VERSION);
 461         disk_super->time = 0;
 462         disk_super->trans_id = 0;
 463         disk_super->held_root = 0;
 464
 465         r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root,
 466                             metadata_len);
 467         if (r < 0)
 468                 goto bad_locked;
 469
 470         r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root,
 471                             data_len);
 472         if (r < 0)
 473                 goto bad_locked;
 474
 475         disk_super->data_mapping_root = cpu_to_le64(pmd->root);
 476         disk_super->device_details_root = cpu_to_le64(pmd->details_root);
 477         disk_super->metadata_block_size = cpu_to_le32(THIN_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
 478         disk_super->metadata_nr_blocks = cpu_to_le64(bdev_size >> SECTOR_TO_BLOCK_SHIFT);
 479         disk_super->data_block_size = cpu_to_le32(pmd->data_block_size);
 480
 481         return dm_tm_commit(pmd->tm, sblock);
 482
 483 bad_locked:
 484         dm_bm_unlock(sblock);
 485         return r;
 486 }
 487
 488 static int __format_metadata(struct dm_pool_metadata *pmd)
 489 {
 490         int r;
 491
 492         r = dm_tm_create_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 493                                  &pmd->tm, &pmd->metadata_sm);
 494         if (r < 0) {
 495                 DMERR("tm_create_with_sm failed");
 496                 return r;
 497         }
 498
 499         pmd->data_sm = dm_sm_disk_create(pmd->tm, 0);
 500         if (IS_ERR(pmd->data_sm)) {
 501                 DMERR("sm_disk_create failed");
 502                 r = PTR_ERR(pmd->data_sm);
 503                 goto bad_cleanup_tm;
 504         }
 505
 506         pmd->nb_tm = dm_tm_create_non_blocking_clone(pmd->tm);
 507         if (!pmd->nb_tm) {
 508                 DMERR("could not create non-blocking clone tm");
 509                 r = -ENOMEM;
 510                 goto bad_cleanup_data_sm;
 511         }
 512
 513         __setup_btree_details(pmd);
 514
 515         r = dm_btree_empty(&pmd->info, &pmd->root);
 516         if (r < 0)
 517                 goto bad_cleanup_nb_tm;
 518
 519         r = dm_btree_empty(&pmd->details_info, &pmd->details_root);
 520         if (r < 0) {
 521                 DMERR("couldn't create devices root");
 522                 goto bad_cleanup_nb_tm;
 523         }
 524
 525         r = __write_initial_superblock(pmd);
 526         if (r)
 527                 goto bad_cleanup_nb_tm;
 528
 529         return 0;
 530
 531 bad_cleanup_nb_tm:
 532         dm_tm_destroy(pmd->nb_tm);
 533 bad_cleanup_data_sm:
 534         dm_sm_destroy(pmd->data_sm);
 535 bad_cleanup_tm:
 536         dm_tm_destroy(pmd->tm);
 537         dm_sm_destroy(pmd->metadata_sm);
 538
 539         return r;
 540 }
 541
 542 static int __check_incompat_features(struct thin_disk_superblock *disk_super,
 543                                      struct dm_pool_metadata *pmd)
 544 {
 545         uint32_t features;
 546
 547         features = le32_to_cpu(disk_super->incompat_flags) & ~THIN_FEATURE_INCOMPAT_SUPP;
 548         if (features) {
 549                 DMERR("could not access metadata due to unsupported optional features (%lx).",
 550                       (unsigned long)features);
 551                 return -EINVAL;
 552         }
 553
 554         /*
 555          * Check for read-only metadata to skip the following RDWR checks.
 556          */
 557         if (get_disk_ro(pmd->bdev->bd_disk))
 558                 return 0;
 559
 560         features = le32_to_cpu(disk_super->compat_ro_flags) & ~THIN_FEATURE_COMPAT_RO_SUPP;
 561         if (features) {
 562                 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
 563                       (unsigned long)features);
 564                 return -EINVAL;
 565         }
 566
 567         return 0;
 568 }
 569
 570 static int __open_metadata(struct dm_pool_metadata *pmd)
 571 {
 572         int r;
 573         struct dm_block *sblock;
 574         struct thin_disk_superblock *disk_super;
 575
 576         r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 577                             &sb_validator, &sblock);
 578         if (r < 0) {
 579                 DMERR("couldn't read superblock");
 580                 return r;
 581         }
 582
 583         disk_super = dm_block_data(sblock);
 584
 585         r = __check_incompat_features(disk_super, pmd);
 586         if (r < 0)
 587                 goto bad_unlock_sblock;
 588
 589         r = dm_tm_open_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 590                                disk_super->metadata_space_map_root,
 591                                sizeof(disk_super->metadata_space_map_root),
 592                                &pmd->tm, &pmd->metadata_sm);
 593         if (r < 0) {
 594                 DMERR("tm_open_with_sm failed");
 595                 goto bad_unlock_sblock;
 596         }
 597
 598         pmd->data_sm = dm_sm_disk_open(pmd->tm, disk_super->data_space_map_root,
 599                                        sizeof(disk_super->data_space_map_root));
 600         if (IS_ERR(pmd->data_sm)) {
 601                 DMERR("sm_disk_open failed");
 602                 r = PTR_ERR(pmd->data_sm);
 603                 goto bad_cleanup_tm;
 604         }
 605
 606         pmd->nb_tm = dm_tm_create_non_blocking_clone(pmd->tm);
 607         if (!pmd->nb_tm) {
 608                 DMERR("could not create non-blocking clone tm");
 609                 r = -ENOMEM;
 610                 goto bad_cleanup_data_sm;
 611         }
 612
 613         __setup_btree_details(pmd);
 614         return dm_bm_unlock(sblock);
 615
 616 bad_cleanup_data_sm:
 617         dm_sm_destroy(pmd->data_sm);
 618 bad_cleanup_tm:
 619         dm_tm_destroy(pmd->tm);
 620         dm_sm_destroy(pmd->metadata_sm);
 621 bad_unlock_sblock:
 622         dm_bm_unlock(sblock);
 623
 624         return r;
 625 }
 626
 627 static int __open_or_format_metadata(struct dm_pool_metadata *pmd, bool format_device)
 628 {
 629         int r, unformatted;
 630
 631         r = __superblock_all_zeroes(pmd->bm, &unformatted);
 632         if (r)
 633                 return r;
 634
 635         if (unformatted)
 636                 return format_device ? __format_metadata(pmd) : -EPERM;
 637
 638         return __open_metadata(pmd);
 639 }
 640
 641 static int __create_persistent_data_objects(struct dm_pool_metadata *pmd, bool format_device)
 642 {
 643         int r;
 644
 645         pmd->bm = dm_block_manager_create(pmd->bdev, THIN_METADATA_BLOCK_SIZE,
 646                                           THIN_METADATA_CACHE_SIZE,
 647                                           THIN_MAX_CONCURRENT_LOCKS);
 648         if (IS_ERR(pmd->bm)) {
 649                 DMERR("could not create block manager");
 650                 return PTR_ERR(pmd->bm);
 651         }
 652
 653         r = __open_or_format_metadata(pmd, format_device);
 654         if (r)
 655                 dm_block_manager_destroy(pmd->bm);
 656
 657         return r;
 658 }
 659
 660 static void __destroy_persistent_data_objects(struct dm_pool_metadata *pmd)
 661 {
 662         dm_sm_destroy(pmd->data_sm);
 663         dm_sm_destroy(pmd->metadata_sm);
 664         dm_tm_destroy(pmd->nb_tm);
 665         dm_tm_destroy(pmd->tm);
 666         dm_block_manager_destroy(pmd->bm);
 667 }
 668
 669 static int __begin_transaction(struct dm_pool_metadata *pmd)
 670 {
 671         int r;
 672         struct thin_disk_superblock *disk_super;
 673         struct dm_block *sblock;
 674
 675         /*
 676          * We re-read the superblock every time.  Shouldn't need to do this
 677          * really.
 678          */
 679         r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 680                             &sb_validator, &sblock);
 681         if (r)
 682                 return r;
 683
 684         disk_super = dm_block_data(sblock);
 685         pmd->time = le32_to_cpu(disk_super->time);
 686         pmd->root = le64_to_cpu(disk_super->data_mapping_root);
 687         pmd->details_root = le64_to_cpu(disk_super->device_details_root);
 688         pmd->trans_id = le64_to_cpu(disk_super->trans_id);
 689         pmd->flags = le32_to_cpu(disk_super->flags);
 690         pmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
 691
 692         dm_bm_unlock(sblock);
 693         return 0;
 694 }
 695
 696 static int __write_changed_details(struct dm_pool_metadata *pmd)
 697 {
 698         int r;
 699         struct dm_thin_device *td, *tmp;
 700         struct disk_device_details details;
 701         uint64_t key;
 702
 703         list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
 704                 if (!td->changed)
 705                         continue;
 706
 707                 key = td->id;
 708
 709                 details.mapped_blocks = cpu_to_le64(td->mapped_blocks);
 710                 details.transaction_id = cpu_to_le64(td->transaction_id);
 711                 details.creation_time = cpu_to_le32(td->creation_time);
 712                 details.snapshotted_time = cpu_to_le32(td->snapshotted_time);
 713                 __dm_bless_for_disk(&details);
 714
 715                 r = dm_btree_insert(&pmd->details_info, pmd->details_root,
 716                                     &key, &details, &pmd->details_root);
 717                 if (r)
 718                         return r;
 719
 720                 if (td->open_count)
 721                         td->changed = 0;
 722                 else {
 723                         list_del(&td->list);
 724                         kfree(td);
 725                 }
 726         }
 727
 728         return 0;
 729 }
 730
 731 static int __commit_transaction(struct dm_pool_metadata *pmd)
 732 {
 733         /*
 734          * FIXME: Associated pool should be made read-only on failure.
 735          */
 736         int r;
 737         size_t metadata_len, data_len;
 738         struct thin_disk_superblock *disk_super;
 739         struct dm_block *sblock;
 740
 741         /*
 742          * We need to know if the thin_disk_superblock exceeds a 512-byte sector.
 743          */
 744         BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512);
 745
 746         r = __write_changed_details(pmd);
 747         if (r < 0)
 748                 return r;
 749
 750         r = dm_sm_commit(pmd->data_sm);
 751         if (r < 0)
 752                 return r;
 753
 754         r = dm_tm_pre_commit(pmd->tm);
 755         if (r < 0)
 756                 return r;
 757
 758         r = dm_sm_root_size(pmd->metadata_sm, &metadata_len);
 759         if (r < 0)
 760                 return r;
 761
 762         r = dm_sm_root_size(pmd->data_sm, &data_len);
 763         if (r < 0)
 764                 return r;
 765
 766         r = superblock_lock(pmd, &sblock);
 767         if (r)
 768                 return r;
 769
 770         disk_super = dm_block_data(sblock);
 771         disk_super->time = cpu_to_le32(pmd->time);
 772         disk_super->data_mapping_root = cpu_to_le64(pmd->root);
 773         disk_super->device_details_root = cpu_to_le64(pmd->details_root);
 774         disk_super->trans_id = cpu_to_le64(pmd->trans_id);
 775         disk_super->flags = cpu_to_le32(pmd->flags);
 776
 777         r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root,
 778                             metadata_len);
 779         if (r < 0)
 780                 goto out_locked;
 781
 782         r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root,
 783                             data_len);
 784         if (r < 0)
 785                 goto out_locked;
 786
 787         return dm_tm_commit(pmd->tm, sblock);
 788
 789 out_locked:
 790         dm_bm_unlock(sblock);
 791         return r;
 792 }
 793
 794 struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
 795                                                sector_t data_block_size,
 796                                                bool format_device)
 797 {
 798         int r;
 799         struct dm_pool_metadata *pmd;
 800
 801         pmd = kmalloc(sizeof(*pmd), GFP_KERNEL);
 802         if (!pmd) {
 803                 DMERR("could not allocate metadata struct");
 804                 return ERR_PTR(-ENOMEM);
 805         }
 806
 807         init_rwsem(&pmd->root_lock);
 808         pmd->time = 0;
 809         INIT_LIST_HEAD(&pmd->thin_devices);
 810         pmd->bdev = bdev;
 811         pmd->data_block_size = data_block_size;
 812
 813         r = __create_persistent_data_objects(pmd, format_device);
 814         if (r) {
 815                 kfree(pmd);
 816                 return ERR_PTR(r);
 817         }
 818
 819         r = __begin_transaction(pmd);
 820         if (r < 0) {
 821                 if (dm_pool_metadata_close(pmd) < 0)
 822                         DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
 823                 return ERR_PTR(r);
 824         }
 825
 826         return pmd;
 827 }
 828
 829 int dm_pool_metadata_close(struct dm_pool_metadata *pmd)
 830 {
 831         int r;
 832         unsigned open_devices = 0;
 833         struct dm_thin_device *td, *tmp;
 834
 835         down_read(&pmd->root_lock);
 836         list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
 837                 if (td->open_count)
 838                         open_devices++;
 839                 else {
 840                         list_del(&td->list);
 841                         kfree(td);
 842                 }
 843         }
 844         up_read(&pmd->root_lock);
 845
 846         if (open_devices) {
 847                 DMERR("attempt to close pmd when %u device(s) are still open",
 848                        open_devices);
 849                 return -EBUSY;
 850         }
 851
 852         r = __commit_transaction(pmd);
 853         if (r < 0)
 854                 DMWARN("%s: __commit_transaction() failed, error = %d",
 855                        __func__, r);
 856
 857         __destroy_persistent_data_objects(pmd);
 858         kfree(pmd);
 859
 860         return 0;
 861 }
 862
 863 /*
 864  * __open_device: Returns @td corresponding to device with id @dev,
 865  * creating it if @create is set and incrementing @td->open_count.
 866  * On failure, @td is undefined.
 867  */
 868 static int __open_device(struct dm_pool_metadata *pmd,
 869                          dm_thin_id dev, int create,
 870                          struct dm_thin_device **td)
 871 {
 872         int r, changed = 0;
 873         struct dm_thin_device *td2;
 874         uint64_t key = dev;
 875         struct disk_device_details details_le;
 876
 877         /*
 878          * If the device is already open, return it.
 879          */
 880         list_for_each_entry(td2, &pmd->thin_devices, list)
 881                 if (td2->id == dev) {
 882                         /*
 883                          * May not create an already-open device.
 884                          */
 885                         if (create)
 886                                 return -EEXIST;
 887
 888                         td2->open_count++;
 889                         *td = td2;
 890                         return 0;
 891                 }
 892
 893         /*
 894          * Check the device exists.
 895          */
 896         r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
 897                             &key, &details_le);
 898         if (r) {
 899                 if (r != -ENODATA || !create)
 900                         return r;
 901
 902                 /*
 903                  * Create new device.
 904                  */
 905                 changed = 1;
 906                 details_le.mapped_blocks = 0;
 907                 details_le.transaction_id = cpu_to_le64(pmd->trans_id);
 908                 details_le.creation_time = cpu_to_le32(pmd->time);
 909                 details_le.snapshotted_time = cpu_to_le32(pmd->time);
 910         }
 911
 912         *td = kmalloc(sizeof(**td), GFP_NOIO);
 913         if (!*td)
 914                 return -ENOMEM;
 915
 916         (*td)->pmd = pmd;
 917         (*td)->id = dev;
 918         (*td)->open_count = 1;
 919         (*td)->changed = changed;
 920         (*td)->mapped_blocks = le64_to_cpu(details_le.mapped_blocks);
 921         (*td)->transaction_id = le64_to_cpu(details_le.transaction_id);
 922         (*td)->creation_time = le32_to_cpu(details_le.creation_time);
 923         (*td)->snapshotted_time = le32_to_cpu(details_le.snapshotted_time);
 924
 925         list_add(&(*td)->list, &pmd->thin_devices);
 926
 927         return 0;
 928 }
 929
 930 static void __close_device(struct dm_thin_device *td)
 931 {
 932         --td->open_count;
 933 }
 934
 935 static int __create_thin(struct dm_pool_metadata *pmd,
 936                          dm_thin_id dev)
 937 {
 938         int r;
 939         dm_block_t dev_root;
 940         uint64_t key = dev;
 941         struct disk_device_details details_le;
 942         struct dm_thin_device *td;
 943         __le64 value;
 944
 945         r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
 946                             &key, &details_le);
 947         if (!r)
 948                 return -EEXIST;
 949
 950         /*
 951          * Create an empty btree for the mappings.
 952          */
 953         r = dm_btree_empty(&pmd->bl_info, &dev_root);
 954         if (r)
 955                 return r;
 956
 957         /*
 958          * Insert it into the main mapping tree.
 959          */
 960         value = cpu_to_le64(dev_root);
 961         __dm_bless_for_disk(&value);
 962         r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
 963         if (r) {
 964                 dm_btree_del(&pmd->bl_info, dev_root);
 965                 return r;
 966         }
 967
 968         r = __open_device(pmd, dev, 1, &td);
 969         if (r) {
 970                 dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
 971                 dm_btree_del(&pmd->bl_info, dev_root);
 972                 return r;
 973         }
 974         __close_device(td);
 975
 976         return r;
 977 }
 978
 979 int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev)
 980 {
 981         int r;
 982
 983         down_write(&pmd->root_lock);
 984         r = __create_thin(pmd, dev);
 985         up_write(&pmd->root_lock);
 986
 987         return r;
 988 }
 989
 990 static int __set_snapshot_details(struct dm_pool_metadata *pmd,
 991                                   struct dm_thin_device *snap,
 992                                   dm_thin_id origin, uint32_t time)
 993 {
 994         int r;
 995         struct dm_thin_device *td;
 996
 997         r = __open_device(pmd, origin, 0, &td);
 998         if (r)
 999                 return r;
1000
1001         td->changed = 1;
1002         td->snapshotted_time = time;
1003
1004         snap->mapped_blocks = td->mapped_blocks;
1005         snap->snapshotted_time = time;
1006         __close_device(td);
1007
1008         return 0;
1009 }
1010
1011 static int __create_snap(struct dm_pool_metadata *pmd,
1012                          dm_thin_id dev, dm_thin_id origin)
1013 {
1014         int r;
1015         dm_block_t origin_root;
1016         uint64_t key = origin, dev_key = dev;
1017         struct dm_thin_device *td;
1018         struct disk_device_details details_le;
1019         __le64 value;
1020
1021         /* check this device is unused */
1022         r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
1023                             &dev_key, &details_le);
1024         if (!r)
1025                 return -EEXIST;
1026
1027         /* find the mapping tree for the origin */
1028         r = dm_btree_lookup(&pmd->tl_info, pmd->root, &key, &value);
1029         if (r)
1030                 return r;
1031         origin_root = le64_to_cpu(value);
1032
1033         /* clone the origin, an inc will do */
1034         dm_tm_inc(pmd->tm, origin_root);
1035
1036         /* insert into the main mapping tree */
1037         value = cpu_to_le64(origin_root);
1038         __dm_bless_for_disk(&value);
1039         key = dev;
1040         r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
1041         if (r) {
1042                 dm_tm_dec(pmd->tm, origin_root);
1043                 return r;
1044         }
1045
1046         pmd->time++;
1047
1048         r = __open_device(pmd, dev, 1, &td);
1049         if (r)
1050                 goto bad;
1051
1052         r = __set_snapshot_details(pmd, td, origin, pmd->time);
1053         __close_device(td);
1054
1055         if (r)
1056                 goto bad;
1057
1058         return 0;
1059
1060 bad:
1061         dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1062         dm_btree_remove(&pmd->details_info, pmd->details_root,
1063                         &key, &pmd->details_root);
1064         return r;
1065 }
1066
1067 int dm_pool_create_snap(struct dm_pool_metadata *pmd,
1068                                  dm_thin_id dev,
1069                                  dm_thin_id origin)
1070 {
1071         int r;
1072
1073         down_write(&pmd->root_lock);
1074         r = __create_snap(pmd, dev, origin);
1075         up_write(&pmd->root_lock);
1076
1077         return r;
1078 }
1079
1080 static int __delete_device(struct dm_pool_metadata *pmd, dm_thin_id dev)
1081 {
1082         int r;
1083         uint64_t key = dev;
1084         struct dm_thin_device *td;
1085
1086         /* TODO: failure should mark the transaction invalid */
1087         r = __open_device(pmd, dev, 0, &td);
1088         if (r)
1089                 return r;
1090
1091         if (td->open_count > 1) {
1092                 __close_device(td);
1093                 return -EBUSY;
1094         }
1095
1096         list_del(&td->list);
1097         kfree(td);
1098         r = dm_btree_remove(&pmd->details_info, pmd->details_root,
1099                             &key, &pmd->details_root);
1100         if (r)
1101                 return r;
1102
1103         r = dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1104         if (r)
1105                 return r;
1106
1107         return 0;
1108 }
1109
1110 int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd,
1111                                dm_thin_id dev)
1112 {
1113         int r;
1114
1115         down_write(&pmd->root_lock);
1116         r = __delete_device(pmd, dev);
1117         up_write(&pmd->root_lock);
1118
1119         return r;
1120 }
1121
1122 int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
1123                                         uint64_t current_id,
1124                                         uint64_t new_id)
1125 {
1126         down_write(&pmd->root_lock);
1127         if (pmd->trans_id != current_id) {
1128                 up_write(&pmd->root_lock);
1129                 DMERR("mismatched transaction id");
1130                 return -EINVAL;
1131         }
1132
1133         pmd->trans_id = new_id;
1134         up_write(&pmd->root_lock);
1135
1136         return 0;
1137 }
1138
1139 int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
1140                                         uint64_t *result)
1141 {
1142         down_read(&pmd->root_lock);
1143         *result = pmd->trans_id;
1144         up_read(&pmd->root_lock);
1145
1146         return 0;
1147 }
1148
1149 static int __reserve_metadata_snap(struct dm_pool_metadata *pmd)
1150 {
1151         int r, inc;
1152         struct thin_disk_superblock *disk_super;
1153         struct dm_block *copy, *sblock;
1154         dm_block_t held_root;
1155
1156         /*
1157          * Copy the superblock.
1158          */
1159         dm_sm_inc_block(pmd->metadata_sm, THIN_SUPERBLOCK_LOCATION);
1160         r = dm_tm_shadow_block(pmd->tm, THIN_SUPERBLOCK_LOCATION,
1161                                &sb_validator, &copy, &inc);
1162         if (r)
1163                 return r;
1164
1165         BUG_ON(!inc);
1166
1167         held_root = dm_block_location(copy);
1168         disk_super = dm_block_data(copy);
1169
1170         if (le64_to_cpu(disk_super->held_root)) {
1171                 DMWARN("Pool metadata snapshot already exists: release this before taking another.");
1172
1173                 dm_tm_dec(pmd->tm, held_root);
1174                 dm_tm_unlock(pmd->tm, copy);
1175                 return -EBUSY;
1176         }
1177
1178         /*
1179          * Wipe the spacemap since we're not publishing this.
1180          */
1181         memset(&disk_super->data_space_map_root, 0,
1182                sizeof(disk_super->data_space_map_root));
1183         memset(&disk_super->metadata_space_map_root, 0,
1184                sizeof(disk_super->metadata_space_map_root));
1185
1186         /*
1187          * Increment the data structures that need to be preserved.
1188          */
1189         dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->data_mapping_root));
1190         dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->device_details_root));
1191         dm_tm_unlock(pmd->tm, copy);
1192
1193         /*
1194          * Write the held root into the superblock.
1195          */
1196         r = superblock_lock(pmd, &sblock);
1197         if (r) {
1198                 dm_tm_dec(pmd->tm, held_root);
1199                 return r;
1200         }
1201
1202         disk_super = dm_block_data(sblock);
1203         disk_super->held_root = cpu_to_le64(held_root);
1204         dm_bm_unlock(sblock);
1205         return 0;
1206 }
1207
1208 int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd)
1209 {
1210         int r;
1211
1212         down_write(&pmd->root_lock);
1213         r = __reserve_metadata_snap(pmd);
1214         up_write(&pmd->root_lock);
1215
1216         return r;
1217 }
1218
1219 static int __release_metadata_snap(struct dm_pool_metadata *pmd)
1220 {
1221         int r;
1222         struct thin_disk_superblock *disk_super;
1223         struct dm_block *sblock, *copy;
1224         dm_block_t held_root;
1225
1226         r = superblock_lock(pmd, &sblock);
1227         if (r)
1228                 return r;
1229
1230         disk_super = dm_block_data(sblock);
1231         held_root = le64_to_cpu(disk_super->held_root);
1232         disk_super->held_root = cpu_to_le64(0);
1233
1234         dm_bm_unlock(sblock);
1235
1236         if (!held_root) {
1237                 DMWARN("No pool metadata snapshot found: nothing to release.");
1238                 return -EINVAL;
1239         }
1240
1241         r = dm_tm_read_lock(pmd->tm, held_root, &sb_validator, &copy);
1242         if (r)
1243                 return r;
1244
1245         disk_super = dm_block_data(copy);
1246         dm_sm_dec_block(pmd->metadata_sm, le64_to_cpu(disk_super->data_mapping_root));
1247         dm_sm_dec_block(pmd->metadata_sm, le64_to_cpu(disk_super->device_details_root));
1248         dm_sm_dec_block(pmd->metadata_sm, held_root);
1249
1250         return dm_tm_unlock(pmd->tm, copy);
1251 }
1252
1253 int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd)
1254 {
1255         int r;
1256
1257         down_write(&pmd->root_lock);
1258         r = __release_metadata_snap(pmd);
1259         up_write(&pmd->root_lock);
1260
1261         return r;
1262 }
1263
1264 static int __get_metadata_snap(struct dm_pool_metadata *pmd,
1265                                dm_block_t *result)
1266 {
1267         int r;
1268         struct thin_disk_superblock *disk_super;
1269         struct dm_block *sblock;
1270
1271         r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
1272                             &sb_validator, &sblock);
1273         if (r)
1274                 return r;
1275
1276         disk_super = dm_block_data(sblock);
1277         *result = le64_to_cpu(disk_super->held_root);
1278
1279         return dm_bm_unlock(sblock);
1280 }
1281
1282 int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd,
1283                               dm_block_t *result)
1284 {
1285         int r;
1286
1287         down_read(&pmd->root_lock);
1288         r = __get_metadata_snap(pmd, result);
1289         up_read(&pmd->root_lock);
1290
1291         return r;
1292 }
1293
1294 int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
1295                              struct dm_thin_device **td)
1296 {
1297         int r;
1298
1299         down_write(&pmd->root_lock);
1300         r = __open_device(pmd, dev, 0, td);
1301         up_write(&pmd->root_lock);
1302
1303         return r;
1304 }
1305
1306 int dm_pool_close_thin_device(struct dm_thin_device *td)
1307 {
1308         down_write(&td->pmd->root_lock);
1309         __close_device(td);
1310         up_write(&td->pmd->root_lock);
1311
1312         return 0;
1313 }
1314
1315 dm_thin_id dm_thin_dev_id(struct dm_thin_device *td)
1316 {
1317         return td->id;
1318 }
1319
1320 static bool __snapshotted_since(struct dm_thin_device *td, uint32_t time)
1321 {
1322         return td->snapshotted_time > time;
1323 }
1324
1325 int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
1326                        int can_block, struct dm_thin_lookup_result *result)
1327 {
1328         int r;
1329         uint64_t block_time = 0;
1330         __le64 value;
1331         struct dm_pool_metadata *pmd = td->pmd;
1332         dm_block_t keys[2] = { td->id, block };
1333
1334         if (can_block) {
1335                 down_read(&pmd->root_lock);
1336                 r = dm_btree_lookup(&pmd->info, pmd->root, keys, &value);
1337                 if (!r)
1338                         block_time = le64_to_cpu(value);
1339                 up_read(&pmd->root_lock);
1340
1341         } else if (down_read_trylock(&pmd->root_lock)) {
1342                 r = dm_btree_lookup(&pmd->nb_info, pmd->root, keys, &value);
1343                 if (!r)
1344                         block_time = le64_to_cpu(value);
1345                 up_read(&pmd->root_lock);
1346
1347         } else
1348                 return -EWOULDBLOCK;
1349
1350         if (!r) {
1351                 dm_block_t exception_block;
1352                 uint32_t exception_time;
1353                 unpack_block_time(block_time, &exception_block,
1354                                   &exception_time);
1355                 result->block = exception_block;
1356                 result->shared = __snapshotted_since(td, exception_time);
1357         }
1358
1359         return r;
1360 }
1361
1362 static int __insert(struct dm_thin_device *td, dm_block_t block,
1363                     dm_block_t data_block)
1364 {
1365         int r, inserted;
1366         __le64 value;
1367         struct dm_pool_metadata *pmd = td->pmd;
1368         dm_block_t keys[2] = { td->id, block };
1369
1370         value = cpu_to_le64(pack_block_time(data_block, pmd->time));
1371         __dm_bless_for_disk(&value);
1372
1373         r = dm_btree_insert_notify(&pmd->info, pmd->root, keys, &value,
1374                                    &pmd->root, &inserted);
1375         if (r)
1376                 return r;
1377
1378         if (inserted) {
1379                 td->mapped_blocks++;
1380                 td->changed = 1;
1381         }
1382
1383         return 0;
1384 }
1385
1386 int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
1387                          dm_block_t data_block)
1388 {
1389         int r;
1390
1391         down_write(&td->pmd->root_lock);
1392         r = __insert(td, block, data_block);
1393         up_write(&td->pmd->root_lock);
1394
1395         return r;
1396 }
1397
1398 static int __remove(struct dm_thin_device *td, dm_block_t block)
1399 {
1400         int r;
1401         struct dm_pool_metadata *pmd = td->pmd;
1402         dm_block_t keys[2] = { td->id, block };
1403
1404         r = dm_btree_remove(&pmd->info, pmd->root, keys, &pmd->root);
1405         if (r)
1406                 return r;
1407
1408         td->mapped_blocks--;
1409         td->changed = 1;
1410
1411         return 0;
1412 }
1413
1414 int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block)
1415 {
1416         int r;
1417
1418         down_write(&td->pmd->root_lock);
1419         r = __remove(td, block);
1420         up_write(&td->pmd->root_lock);
1421
1422         return r;
1423 }
1424
1425 int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result)
1426 {
1427         int r;
1428
1429         down_write(&pmd->root_lock);
1430         r = dm_sm_new_block(pmd->data_sm, result);
1431         up_write(&pmd->root_lock);
1432
1433         return r;
1434 }
1435
1436 int dm_pool_commit_metadata(struct dm_pool_metadata *pmd)
1437 {
1438         int r;
1439
1440         down_write(&pmd->root_lock);
1441
1442         r = __commit_transaction(pmd);
1443         if (r <= 0)
1444                 goto out;
1445
1446         /*
1447          * Open the next transaction.
1448          */
1449         r = __begin_transaction(pmd);
1450 out:
1451         up_write(&pmd->root_lock);
1452         return r;
1453 }
1454
1455 int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, dm_block_t *result)
1456 {
1457         int r;
1458
1459         down_read(&pmd->root_lock);
1460         r = dm_sm_get_nr_free(pmd->data_sm, result);
1461         up_read(&pmd->root_lock);
1462
1463         return r;
1464 }
1465
1466 int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
1467                                           dm_block_t *result)
1468 {
1469         int r;
1470
1471         down_read(&pmd->root_lock);
1472         r = dm_sm_get_nr_free(pmd->metadata_sm, result);
1473         up_read(&pmd->root_lock);
1474
1475         return r;
1476 }
1477
1478 int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
1479                                   dm_block_t *result)
1480 {
1481         int r;
1482
1483         down_read(&pmd->root_lock);
1484         r = dm_sm_get_nr_blocks(pmd->metadata_sm, result);
1485         up_read(&pmd->root_lock);
1486
1487         return r;
1488 }
1489
1490 int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result)
1491 {
1492         down_read(&pmd->root_lock);
1493         *result = pmd->data_block_size;
1494         up_read(&pmd->root_lock);
1495
1496         return 0;
1497 }
1498
1499 int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result)
1500 {
1501         int r;
1502
1503         down_read(&pmd->root_lock);
1504         r = dm_sm_get_nr_blocks(pmd->data_sm, result);
1505         up_read(&pmd->root_lock);
1506
1507         return r;
1508 }
1509
1510 int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result)
1511 {
1512         struct dm_pool_metadata *pmd = td->pmd;
1513
1514         down_read(&pmd->root_lock);
1515         *result = td->mapped_blocks;
1516         up_read(&pmd->root_lock);
1517
1518         return 0;
1519 }
1520
1521 static int __highest_block(struct dm_thin_device *td, dm_block_t *result)
1522 {
1523         int r;
1524         __le64 value_le;
1525         dm_block_t thin_root;
1526         struct dm_pool_metadata *pmd = td->pmd;
1527
1528         r = dm_btree_lookup(&pmd->tl_info, pmd->root, &td->id, &value_le);
1529         if (r)
1530                 return r;
1531
1532         thin_root = le64_to_cpu(value_le);
1533
1534         return dm_btree_find_highest_key(&pmd->bl_info, thin_root, result);
1535 }
1536
1537 int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
1538                                      dm_block_t *result)
1539 {
1540         int r;
1541         struct dm_pool_metadata *pmd = td->pmd;
1542
1543         down_read(&pmd->root_lock);
1544         r = __highest_block(td, result);
1545         up_read(&pmd->root_lock);
1546
1547         return r;
1548 }
1549
1550 static int __resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
1551 {
1552         int r;
1553         dm_block_t old_count;
1554
1555         r = dm_sm_get_nr_blocks(pmd->data_sm, &old_count);
1556         if (r)
1557                 return r;
1558
1559         if (new_count == old_count)
1560                 return 0;
1561
1562         if (new_count < old_count) {
1563                 DMERR("cannot reduce size of data device");
1564                 return -EINVAL;
1565         }
1566
1567         return dm_sm_extend(pmd->data_sm, new_count - old_count);
1568 }
1569
1570 int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
1571 {
1572         int r;
1573
1574         down_write(&pmd->root_lock);
1575         r = __resize_data_dev(pmd, new_count);
1576         up_write(&pmd->root_lock);
1577
1578         return r;
1579 }