drivers/md/dm-thin-metadata.c

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