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 40
  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          * Pre-commit callback.
 193          *
 194          * This allows the thin provisioning target to run a callback before
 195          * the metadata are committed.
 196          */
 197         dm_pool_pre_commit_fn pre_commit_fn;
 198         void *pre_commit_context;
 199
 200         /*
 201          * We reserve a section of the metadata for commit overhead.
 202          * All reported space does *not* include this.
 203          */
 204         dm_block_t metadata_reserve;
 205
 206         /*
 207          * Set if a transaction has to be aborted but the attempt to roll back
 208          * to the previous (good) transaction failed.  The only pool metadata
 209          * operation possible in this state is the closing of the device.
 210          */
 211         bool fail_io:1;
 212
 213         /*
 214          * Set once a thin-pool has been accessed through one of the interfaces
 215          * that imply the pool is in-service (e.g. thin devices created/deleted,
 216          * thin-pool message, metadata snapshots, etc).
 217          */
 218         bool in_service:1;
 219
 220         /*
 221          * Reading the space map roots can fail, so we read it into these
 222          * buffers before the superblock is locked and updated.
 223          */
 224         __u8 data_space_map_root[SPACE_MAP_ROOT_SIZE];
 225         __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
 226 };
 227
 228 struct dm_thin_device {
 229         struct list_head list;
 230         struct dm_pool_metadata *pmd;
 231         dm_thin_id id;
 232
 233         int open_count;
 234         bool changed:1;
 235         bool aborted_with_changes:1;
 236         uint64_t mapped_blocks;
 237         uint64_t transaction_id;
 238         uint32_t creation_time;
 239         uint32_t snapshotted_time;
 240 };
 241
 242 /*----------------------------------------------------------------
 243  * superblock validator
 244  *--------------------------------------------------------------*/
 245
 246 #define SUPERBLOCK_CSUM_XOR 160774
 247
 248 static void sb_prepare_for_write(struct dm_block_validator *v,
 249                                  struct dm_block *b,
 250                                  size_t block_size)
 251 {
 252         struct thin_disk_superblock *disk_super = dm_block_data(b);
 253
 254         disk_super->blocknr = cpu_to_le64(dm_block_location(b));
 255         disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 256                                                       block_size - sizeof(__le32),
 257                                                       SUPERBLOCK_CSUM_XOR));
 258 }
 259
 260 static int sb_check(struct dm_block_validator *v,
 261                     struct dm_block *b,
 262                     size_t block_size)
 263 {
 264         struct thin_disk_superblock *disk_super = dm_block_data(b);
 265         __le32 csum_le;
 266
 267         if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
 268                 DMERR("sb_check failed: blocknr %llu: "
 269                       "wanted %llu", le64_to_cpu(disk_super->blocknr),
 270                       (unsigned long long)dm_block_location(b));
 271                 return -ENOTBLK;
 272         }
 273
 274         if (le64_to_cpu(disk_super->magic) != THIN_SUPERBLOCK_MAGIC) {
 275                 DMERR("sb_check failed: magic %llu: "
 276                       "wanted %llu", le64_to_cpu(disk_super->magic),
 277                       (unsigned long long)THIN_SUPERBLOCK_MAGIC);
 278                 return -EILSEQ;
 279         }
 280
 281         csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
 282                                              block_size - sizeof(__le32),
 283                                              SUPERBLOCK_CSUM_XOR));
 284         if (csum_le != disk_super->csum) {
 285                 DMERR("sb_check failed: csum %u: wanted %u",
 286                       le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
 287                 return -EILSEQ;
 288         }
 289
 290         return 0;
 291 }
 292
 293 static struct dm_block_validator sb_validator = {
 294         .name = "superblock",
 295         .prepare_for_write = sb_prepare_for_write,
 296         .check = sb_check
 297 };
 298
 299 /*----------------------------------------------------------------
 300  * Methods for the btree value types
 301  *--------------------------------------------------------------*/
 302
 303 static uint64_t pack_block_time(dm_block_t b, uint32_t t)
 304 {
 305         return (b << 24) | t;
 306 }
 307
 308 static void unpack_block_time(uint64_t v, dm_block_t *b, uint32_t *t)
 309 {
 310         *b = v >> 24;
 311         *t = v & ((1 << 24) - 1);
 312 }
 313
 314 static void data_block_inc(void *context, const void *value_le)
 315 {
 316         struct dm_space_map *sm = context;
 317         __le64 v_le;
 318         uint64_t b;
 319         uint32_t t;
 320
 321         memcpy(&v_le, value_le, sizeof(v_le));
 322         unpack_block_time(le64_to_cpu(v_le), &b, &t);
 323         dm_sm_inc_block(sm, b);
 324 }
 325
 326 static void data_block_dec(void *context, const void *value_le)
 327 {
 328         struct dm_space_map *sm = context;
 329         __le64 v_le;
 330         uint64_t b;
 331         uint32_t t;
 332
 333         memcpy(&v_le, value_le, sizeof(v_le));
 334         unpack_block_time(le64_to_cpu(v_le), &b, &t);
 335         dm_sm_dec_block(sm, b);
 336 }
 337
 338 static int data_block_equal(void *context, const void *value1_le, const void *value2_le)
 339 {
 340         __le64 v1_le, v2_le;
 341         uint64_t b1, b2;
 342         uint32_t t;
 343
 344         memcpy(&v1_le, value1_le, sizeof(v1_le));
 345         memcpy(&v2_le, value2_le, sizeof(v2_le));
 346         unpack_block_time(le64_to_cpu(v1_le), &b1, &t);
 347         unpack_block_time(le64_to_cpu(v2_le), &b2, &t);
 348
 349         return b1 == b2;
 350 }
 351
 352 static void subtree_inc(void *context, const void *value)
 353 {
 354         struct dm_btree_info *info = context;
 355         __le64 root_le;
 356         uint64_t root;
 357
 358         memcpy(&root_le, value, sizeof(root_le));
 359         root = le64_to_cpu(root_le);
 360         dm_tm_inc(info->tm, root);
 361 }
 362
 363 static void subtree_dec(void *context, const void *value)
 364 {
 365         struct dm_btree_info *info = context;
 366         __le64 root_le;
 367         uint64_t root;
 368
 369         memcpy(&root_le, value, sizeof(root_le));
 370         root = le64_to_cpu(root_le);
 371         if (dm_btree_del(info, root))
 372                 DMERR("btree delete failed");
 373 }
 374
 375 static int subtree_equal(void *context, const void *value1_le, const void *value2_le)
 376 {
 377         __le64 v1_le, v2_le;
 378         memcpy(&v1_le, value1_le, sizeof(v1_le));
 379         memcpy(&v2_le, value2_le, sizeof(v2_le));
 380
 381         return v1_le == v2_le;
 382 }
 383
 384 /*----------------------------------------------------------------*/
 385
 386 /*
 387  * Variant that is used for in-core only changes or code that
 388  * shouldn't put the pool in service on its own (e.g. commit).
 389  */
 390 static inline void pmd_write_lock_in_core(struct dm_pool_metadata *pmd)
 391         __acquires(pmd->root_lock)
 392 {
 393         down_write(&pmd->root_lock);
 394 }
 395
 396 static inline void pmd_write_lock(struct dm_pool_metadata *pmd)
 397 {
 398         pmd_write_lock_in_core(pmd);
 399         if (unlikely(!pmd->in_service))
 400                 pmd->in_service = true;
 401 }
 402
 403 static inline void pmd_write_unlock(struct dm_pool_metadata *pmd)
 404         __releases(pmd->root_lock)
 405 {
 406         up_write(&pmd->root_lock);
 407 }
 408
 409 /*----------------------------------------------------------------*/
 410
 411 static int superblock_lock_zero(struct dm_pool_metadata *pmd,
 412                                 struct dm_block **sblock)
 413 {
 414         return dm_bm_write_lock_zero(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 415                                      &sb_validator, sblock);
 416 }
 417
 418 static int superblock_lock(struct dm_pool_metadata *pmd,
 419                            struct dm_block **sblock)
 420 {
 421         return dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 422                                 &sb_validator, sblock);
 423 }
 424
 425 static int __superblock_all_zeroes(struct dm_block_manager *bm, int *result)
 426 {
 427         int r;
 428         unsigned i;
 429         struct dm_block *b;
 430         __le64 *data_le, zero = cpu_to_le64(0);
 431         unsigned block_size = dm_bm_block_size(bm) / sizeof(__le64);
 432
 433         /*
 434          * We can't use a validator here - it may be all zeroes.
 435          */
 436         r = dm_bm_read_lock(bm, THIN_SUPERBLOCK_LOCATION, NULL, &b);
 437         if (r)
 438                 return r;
 439
 440         data_le = dm_block_data(b);
 441         *result = 1;
 442         for (i = 0; i < block_size; i++) {
 443                 if (data_le[i] != zero) {
 444                         *result = 0;
 445                         break;
 446                 }
 447         }
 448
 449         dm_bm_unlock(b);
 450
 451         return 0;
 452 }
 453
 454 static void __setup_btree_details(struct dm_pool_metadata *pmd)
 455 {
 456         pmd->info.tm = pmd->tm;
 457         pmd->info.levels = 2;
 458         pmd->info.value_type.context = pmd->data_sm;
 459         pmd->info.value_type.size = sizeof(__le64);
 460         pmd->info.value_type.inc = data_block_inc;
 461         pmd->info.value_type.dec = data_block_dec;
 462         pmd->info.value_type.equal = data_block_equal;
 463
 464         memcpy(&pmd->nb_info, &pmd->info, sizeof(pmd->nb_info));
 465         pmd->nb_info.tm = pmd->nb_tm;
 466
 467         pmd->tl_info.tm = pmd->tm;
 468         pmd->tl_info.levels = 1;
 469         pmd->tl_info.value_type.context = &pmd->bl_info;
 470         pmd->tl_info.value_type.size = sizeof(__le64);
 471         pmd->tl_info.value_type.inc = subtree_inc;
 472         pmd->tl_info.value_type.dec = subtree_dec;
 473         pmd->tl_info.value_type.equal = subtree_equal;
 474
 475         pmd->bl_info.tm = pmd->tm;
 476         pmd->bl_info.levels = 1;
 477         pmd->bl_info.value_type.context = pmd->data_sm;
 478         pmd->bl_info.value_type.size = sizeof(__le64);
 479         pmd->bl_info.value_type.inc = data_block_inc;
 480         pmd->bl_info.value_type.dec = data_block_dec;
 481         pmd->bl_info.value_type.equal = data_block_equal;
 482
 483         pmd->details_info.tm = pmd->tm;
 484         pmd->details_info.levels = 1;
 485         pmd->details_info.value_type.context = NULL;
 486         pmd->details_info.value_type.size = sizeof(struct disk_device_details);
 487         pmd->details_info.value_type.inc = NULL;
 488         pmd->details_info.value_type.dec = NULL;
 489         pmd->details_info.value_type.equal = NULL;
 490 }
 491
 492 static int save_sm_roots(struct dm_pool_metadata *pmd)
 493 {
 494         int r;
 495         size_t len;
 496
 497         r = dm_sm_root_size(pmd->metadata_sm, &len);
 498         if (r < 0)
 499                 return r;
 500
 501         r = dm_sm_copy_root(pmd->metadata_sm, &pmd->metadata_space_map_root, len);
 502         if (r < 0)
 503                 return r;
 504
 505         r = dm_sm_root_size(pmd->data_sm, &len);
 506         if (r < 0)
 507                 return r;
 508
 509         return dm_sm_copy_root(pmd->data_sm, &pmd->data_space_map_root, len);
 510 }
 511
 512 static void copy_sm_roots(struct dm_pool_metadata *pmd,
 513                           struct thin_disk_superblock *disk)
 514 {
 515         memcpy(&disk->metadata_space_map_root,
 516                &pmd->metadata_space_map_root,
 517                sizeof(pmd->metadata_space_map_root));
 518
 519         memcpy(&disk->data_space_map_root,
 520                &pmd->data_space_map_root,
 521                sizeof(pmd->data_space_map_root));
 522 }
 523
 524 static int __write_initial_superblock(struct dm_pool_metadata *pmd)
 525 {
 526         int r;
 527         struct dm_block *sblock;
 528         struct thin_disk_superblock *disk_super;
 529         sector_t bdev_size = i_size_read(pmd->bdev->bd_inode) >> SECTOR_SHIFT;
 530
 531         if (bdev_size > THIN_METADATA_MAX_SECTORS)
 532                 bdev_size = THIN_METADATA_MAX_SECTORS;
 533
 534         r = dm_sm_commit(pmd->data_sm);
 535         if (r < 0)
 536                 return r;
 537
 538         r = dm_tm_pre_commit(pmd->tm);
 539         if (r < 0)
 540                 return r;
 541
 542         r = save_sm_roots(pmd);
 543         if (r < 0)
 544                 return r;
 545
 546         r = superblock_lock_zero(pmd, &sblock);
 547         if (r)
 548                 return r;
 549
 550         disk_super = dm_block_data(sblock);
 551         disk_super->flags = 0;
 552         memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
 553         disk_super->magic = cpu_to_le64(THIN_SUPERBLOCK_MAGIC);
 554         disk_super->version = cpu_to_le32(THIN_VERSION);
 555         disk_super->time = 0;
 556         disk_super->trans_id = 0;
 557         disk_super->held_root = 0;
 558
 559         copy_sm_roots(pmd, disk_super);
 560
 561         disk_super->data_mapping_root = cpu_to_le64(pmd->root);
 562         disk_super->device_details_root = cpu_to_le64(pmd->details_root);
 563         disk_super->metadata_block_size = cpu_to_le32(THIN_METADATA_BLOCK_SIZE);
 564         disk_super->metadata_nr_blocks = cpu_to_le64(bdev_size >> SECTOR_TO_BLOCK_SHIFT);
 565         disk_super->data_block_size = cpu_to_le32(pmd->data_block_size);
 566
 567         return dm_tm_commit(pmd->tm, sblock);
 568 }
 569
 570 static int __format_metadata(struct dm_pool_metadata *pmd)
 571 {
 572         int r;
 573
 574         r = dm_tm_create_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 575                                  &pmd->tm, &pmd->metadata_sm);
 576         if (r < 0) {
 577                 DMERR("tm_create_with_sm failed");
 578                 return r;
 579         }
 580
 581         pmd->data_sm = dm_sm_disk_create(pmd->tm, 0);
 582         if (IS_ERR(pmd->data_sm)) {
 583                 DMERR("sm_disk_create failed");
 584                 r = PTR_ERR(pmd->data_sm);
 585                 goto bad_cleanup_tm;
 586         }
 587
 588         pmd->nb_tm = dm_tm_create_non_blocking_clone(pmd->tm);
 589         if (!pmd->nb_tm) {
 590                 DMERR("could not create non-blocking clone tm");
 591                 r = -ENOMEM;
 592                 goto bad_cleanup_data_sm;
 593         }
 594
 595         __setup_btree_details(pmd);
 596
 597         r = dm_btree_empty(&pmd->info, &pmd->root);
 598         if (r < 0)
 599                 goto bad_cleanup_nb_tm;
 600
 601         r = dm_btree_empty(&pmd->details_info, &pmd->details_root);
 602         if (r < 0) {
 603                 DMERR("couldn't create devices root");
 604                 goto bad_cleanup_nb_tm;
 605         }
 606
 607         r = __write_initial_superblock(pmd);
 608         if (r)
 609                 goto bad_cleanup_nb_tm;
 610
 611         return 0;
 612
 613 bad_cleanup_nb_tm:
 614         dm_tm_destroy(pmd->nb_tm);
 615 bad_cleanup_data_sm:
 616         dm_sm_destroy(pmd->data_sm);
 617 bad_cleanup_tm:
 618         dm_tm_destroy(pmd->tm);
 619         dm_sm_destroy(pmd->metadata_sm);
 620
 621         return r;
 622 }
 623
 624 static int __check_incompat_features(struct thin_disk_superblock *disk_super,
 625                                      struct dm_pool_metadata *pmd)
 626 {
 627         uint32_t features;
 628
 629         features = le32_to_cpu(disk_super->incompat_flags) & ~THIN_FEATURE_INCOMPAT_SUPP;
 630         if (features) {
 631                 DMERR("could not access metadata due to unsupported optional features (%lx).",
 632                       (unsigned long)features);
 633                 return -EINVAL;
 634         }
 635
 636         /*
 637          * Check for read-only metadata to skip the following RDWR checks.
 638          */
 639         if (bdev_read_only(pmd->bdev))
 640                 return 0;
 641
 642         features = le32_to_cpu(disk_super->compat_ro_flags) & ~THIN_FEATURE_COMPAT_RO_SUPP;
 643         if (features) {
 644                 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
 645                       (unsigned long)features);
 646                 return -EINVAL;
 647         }
 648
 649         return 0;
 650 }
 651
 652 static int __open_metadata(struct dm_pool_metadata *pmd)
 653 {
 654         int r;
 655         struct dm_block *sblock;
 656         struct thin_disk_superblock *disk_super;
 657
 658         r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 659                             &sb_validator, &sblock);
 660         if (r < 0) {
 661                 DMERR("couldn't read superblock");
 662                 return r;
 663         }
 664
 665         disk_super = dm_block_data(sblock);
 666
 667         /* Verify the data block size hasn't changed */
 668         if (le32_to_cpu(disk_super->data_block_size) != pmd->data_block_size) {
 669                 DMERR("changing the data block size (from %u to %llu) is not supported",
 670                       le32_to_cpu(disk_super->data_block_size),
 671                       (unsigned long long)pmd->data_block_size);
 672                 r = -EINVAL;
 673                 goto bad_unlock_sblock;
 674         }
 675
 676         r = __check_incompat_features(disk_super, pmd);
 677         if (r < 0)
 678                 goto bad_unlock_sblock;
 679
 680         r = dm_tm_open_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 681                                disk_super->metadata_space_map_root,
 682                                sizeof(disk_super->metadata_space_map_root),
 683                                &pmd->tm, &pmd->metadata_sm);
 684         if (r < 0) {
 685                 DMERR("tm_open_with_sm failed");
 686                 goto bad_unlock_sblock;
 687         }
 688
 689         pmd->data_sm = dm_sm_disk_open(pmd->tm, disk_super->data_space_map_root,
 690                                        sizeof(disk_super->data_space_map_root));
 691         if (IS_ERR(pmd->data_sm)) {
 692                 DMERR("sm_disk_open failed");
 693                 r = PTR_ERR(pmd->data_sm);
 694                 goto bad_cleanup_tm;
 695         }
 696
 697         pmd->nb_tm = dm_tm_create_non_blocking_clone(pmd->tm);
 698         if (!pmd->nb_tm) {
 699                 DMERR("could not create non-blocking clone tm");
 700                 r = -ENOMEM;
 701                 goto bad_cleanup_data_sm;
 702         }
 703
 704         __setup_btree_details(pmd);
 705         dm_bm_unlock(sblock);
 706
 707         return 0;
 708
 709 bad_cleanup_data_sm:
 710         dm_sm_destroy(pmd->data_sm);
 711 bad_cleanup_tm:
 712         dm_tm_destroy(pmd->tm);
 713         dm_sm_destroy(pmd->metadata_sm);
 714 bad_unlock_sblock:
 715         dm_bm_unlock(sblock);
 716
 717         return r;
 718 }
 719
 720 static int __open_or_format_metadata(struct dm_pool_metadata *pmd, bool format_device)
 721 {
 722         int r, unformatted;
 723
 724         r = __superblock_all_zeroes(pmd->bm, &unformatted);
 725         if (r)
 726                 return r;
 727
 728         if (unformatted)
 729                 return format_device ? __format_metadata(pmd) : -EPERM;
 730
 731         return __open_metadata(pmd);
 732 }
 733
 734 static int __create_persistent_data_objects(struct dm_pool_metadata *pmd, bool format_device)
 735 {
 736         int r;
 737
 738         pmd->bm = dm_block_manager_create(pmd->bdev, THIN_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
 739                                           THIN_MAX_CONCURRENT_LOCKS);
 740         if (IS_ERR(pmd->bm)) {
 741                 DMERR("could not create block manager");
 742                 r = PTR_ERR(pmd->bm);
 743                 pmd->bm = NULL;
 744                 return r;
 745         }
 746
 747         r = __open_or_format_metadata(pmd, format_device);
 748         if (r) {
 749                 dm_block_manager_destroy(pmd->bm);
 750                 pmd->bm = NULL;
 751         }
 752
 753         return r;
 754 }
 755
 756 static void __destroy_persistent_data_objects(struct dm_pool_metadata *pmd)
 757 {
 758         dm_sm_destroy(pmd->data_sm);
 759         dm_sm_destroy(pmd->metadata_sm);
 760         dm_tm_destroy(pmd->nb_tm);
 761         dm_tm_destroy(pmd->tm);
 762         dm_block_manager_destroy(pmd->bm);
 763 }
 764
 765 static int __begin_transaction(struct dm_pool_metadata *pmd)
 766 {
 767         int r;
 768         struct thin_disk_superblock *disk_super;
 769         struct dm_block *sblock;
 770
 771         /*
 772          * We re-read the superblock every time.  Shouldn't need to do this
 773          * really.
 774          */
 775         r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
 776                             &sb_validator, &sblock);
 777         if (r)
 778                 return r;
 779
 780         disk_super = dm_block_data(sblock);
 781         pmd->time = le32_to_cpu(disk_super->time);
 782         pmd->root = le64_to_cpu(disk_super->data_mapping_root);
 783         pmd->details_root = le64_to_cpu(disk_super->device_details_root);
 784         pmd->trans_id = le64_to_cpu(disk_super->trans_id);
 785         pmd->flags = le32_to_cpu(disk_super->flags);
 786         pmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
 787
 788         dm_bm_unlock(sblock);
 789         return 0;
 790 }
 791
 792 static int __write_changed_details(struct dm_pool_metadata *pmd)
 793 {
 794         int r;
 795         struct dm_thin_device *td, *tmp;
 796         struct disk_device_details details;
 797         uint64_t key;
 798
 799         list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
 800                 if (!td->changed)
 801                         continue;
 802
 803                 key = td->id;
 804
 805                 details.mapped_blocks = cpu_to_le64(td->mapped_blocks);
 806                 details.transaction_id = cpu_to_le64(td->transaction_id);
 807                 details.creation_time = cpu_to_le32(td->creation_time);
 808                 details.snapshotted_time = cpu_to_le32(td->snapshotted_time);
 809                 __dm_bless_for_disk(&details);
 810
 811                 r = dm_btree_insert(&pmd->details_info, pmd->details_root,
 812                                     &key, &details, &pmd->details_root);
 813                 if (r)
 814                         return r;
 815
 816                 if (td->open_count)
 817                         td->changed = false;
 818                 else {
 819                         list_del(&td->list);
 820                         kfree(td);
 821                 }
 822         }
 823
 824         return 0;
 825 }
 826
 827 static int __commit_transaction(struct dm_pool_metadata *pmd)
 828 {
 829         int r;
 830         struct thin_disk_superblock *disk_super;
 831         struct dm_block *sblock;
 832
 833         /*
 834          * We need to know if the thin_disk_superblock exceeds a 512-byte sector.
 835          */
 836         BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512);
 837         BUG_ON(!rwsem_is_locked(&pmd->root_lock));
 838
 839         if (unlikely(!pmd->in_service))
 840                 return 0;
 841
 842         if (pmd->pre_commit_fn) {
 843                 r = pmd->pre_commit_fn(pmd->pre_commit_context);
 844                 if (r < 0) {
 845                         DMERR("pre-commit callback failed");
 846                         return r;
 847                 }
 848         }
 849
 850         r = __write_changed_details(pmd);
 851         if (r < 0)
 852                 return r;
 853
 854         r = dm_sm_commit(pmd->data_sm);
 855         if (r < 0)
 856                 return r;
 857
 858         r = dm_tm_pre_commit(pmd->tm);
 859         if (r < 0)
 860                 return r;
 861
 862         r = save_sm_roots(pmd);
 863         if (r < 0)
 864                 return r;
 865
 866         r = superblock_lock(pmd, &sblock);
 867         if (r)
 868                 return r;
 869
 870         disk_super = dm_block_data(sblock);
 871         disk_super->time = cpu_to_le32(pmd->time);
 872         disk_super->data_mapping_root = cpu_to_le64(pmd->root);
 873         disk_super->device_details_root = cpu_to_le64(pmd->details_root);
 874         disk_super->trans_id = cpu_to_le64(pmd->trans_id);
 875         disk_super->flags = cpu_to_le32(pmd->flags);
 876
 877         copy_sm_roots(pmd, disk_super);
 878
 879         return dm_tm_commit(pmd->tm, sblock);
 880 }
 881
 882 static void __set_metadata_reserve(struct dm_pool_metadata *pmd)
 883 {
 884         int r;
 885         dm_block_t total;
 886         dm_block_t max_blocks = 4096; /* 16M */
 887
 888         r = dm_sm_get_nr_blocks(pmd->metadata_sm, &total);
 889         if (r) {
 890                 DMERR("could not get size of metadata device");
 891                 pmd->metadata_reserve = max_blocks;
 892         } else
 893                 pmd->metadata_reserve = min(max_blocks, div_u64(total, 10));
 894 }
 895
 896 struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
 897                                                sector_t data_block_size,
 898                                                bool format_device)
 899 {
 900         int r;
 901         struct dm_pool_metadata *pmd;
 902
 903         pmd = kmalloc(sizeof(*pmd), GFP_KERNEL);
 904         if (!pmd) {
 905                 DMERR("could not allocate metadata struct");
 906                 return ERR_PTR(-ENOMEM);
 907         }
 908
 909         init_rwsem(&pmd->root_lock);
 910         pmd->time = 0;
 911         INIT_LIST_HEAD(&pmd->thin_devices);
 912         pmd->fail_io = false;
 913         pmd->in_service = false;
 914         pmd->bdev = bdev;
 915         pmd->data_block_size = data_block_size;
 916         pmd->pre_commit_fn = NULL;
 917         pmd->pre_commit_context = NULL;
 918
 919         r = __create_persistent_data_objects(pmd, format_device);
 920         if (r) {
 921                 kfree(pmd);
 922                 return ERR_PTR(r);
 923         }
 924
 925         r = __begin_transaction(pmd);
 926         if (r < 0) {
 927                 if (dm_pool_metadata_close(pmd) < 0)
 928                         DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
 929                 return ERR_PTR(r);
 930         }
 931
 932         __set_metadata_reserve(pmd);
 933
 934         return pmd;
 935 }
 936
 937 int dm_pool_metadata_close(struct dm_pool_metadata *pmd)
 938 {
 939         int r;
 940         unsigned open_devices = 0;
 941         struct dm_thin_device *td, *tmp;
 942
 943         down_read(&pmd->root_lock);
 944         list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
 945                 if (td->open_count)
 946                         open_devices++;
 947                 else {
 948                         list_del(&td->list);
 949                         kfree(td);
 950                 }
 951         }
 952         up_read(&pmd->root_lock);
 953
 954         if (open_devices) {
 955                 DMERR("attempt to close pmd when %u device(s) are still open",
 956                        open_devices);
 957                 return -EBUSY;
 958         }
 959
 960         pmd_write_lock_in_core(pmd);
 961         if (!pmd->fail_io && !dm_bm_is_read_only(pmd->bm)) {
 962                 r = __commit_transaction(pmd);
 963                 if (r < 0)
 964                         DMWARN("%s: __commit_transaction() failed, error = %d",
 965                                __func__, r);
 966         }
 967         pmd_write_unlock(pmd);
 968         if (!pmd->fail_io)
 969                 __destroy_persistent_data_objects(pmd);
 970
 971         kfree(pmd);
 972         return 0;
 973 }
 974
 975 /*
 976  * __open_device: Returns @td corresponding to device with id @dev,
 977  * creating it if @create is set and incrementing @td->open_count.
 978  * On failure, @td is undefined.
 979  */
 980 static int __open_device(struct dm_pool_metadata *pmd,
 981                          dm_thin_id dev, int create,
 982                          struct dm_thin_device **td)
 983 {
 984         int r, changed = 0;
 985         struct dm_thin_device *td2;
 986         uint64_t key = dev;
 987         struct disk_device_details details_le;
 988
 989         /*
 990          * If the device is already open, return it.
 991          */
 992         list_for_each_entry(td2, &pmd->thin_devices, list)
 993                 if (td2->id == dev) {
 994                         /*
 995                          * May not create an already-open device.
 996                          */
 997                         if (create)
 998                                 return -EEXIST;
 999
1000                         td2->open_count++;
1001                         *td = td2;
1002                         return 0;
1003                 }
1004
1005         /*
1006          * Check the device exists.
1007          */
1008         r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
1009                             &key, &details_le);
1010         if (r) {
1011                 if (r != -ENODATA || !create)
1012                         return r;
1013
1014                 /*
1015                  * Create new device.
1016                  */
1017                 changed = 1;
1018                 details_le.mapped_blocks = 0;
1019                 details_le.transaction_id = cpu_to_le64(pmd->trans_id);
1020                 details_le.creation_time = cpu_to_le32(pmd->time);
1021                 details_le.snapshotted_time = cpu_to_le32(pmd->time);
1022         }
1023
1024         *td = kmalloc(sizeof(**td), GFP_NOIO);
1025         if (!*td)
1026                 return -ENOMEM;
1027
1028         (*td)->pmd = pmd;
1029         (*td)->id = dev;
1030         (*td)->open_count = 1;
1031         (*td)->changed = changed;
1032         (*td)->aborted_with_changes = false;
1033         (*td)->mapped_blocks = le64_to_cpu(details_le.mapped_blocks);
1034         (*td)->transaction_id = le64_to_cpu(details_le.transaction_id);
1035         (*td)->creation_time = le32_to_cpu(details_le.creation_time);
1036         (*td)->snapshotted_time = le32_to_cpu(details_le.snapshotted_time);
1037
1038         list_add(&(*td)->list, &pmd->thin_devices);
1039
1040         return 0;
1041 }
1042
1043 static void __close_device(struct dm_thin_device *td)
1044 {
1045         --td->open_count;
1046 }
1047
1048 static int __create_thin(struct dm_pool_metadata *pmd,
1049                          dm_thin_id dev)
1050 {
1051         int r;
1052         dm_block_t dev_root;
1053         uint64_t key = dev;
1054         struct dm_thin_device *td;
1055         __le64 value;
1056
1057         r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
1058                             &key, NULL);
1059         if (!r)
1060                 return -EEXIST;
1061
1062         /*
1063          * Create an empty btree for the mappings.
1064          */
1065         r = dm_btree_empty(&pmd->bl_info, &dev_root);
1066         if (r)
1067                 return r;
1068
1069         /*
1070          * Insert it into the main mapping tree.
1071          */
1072         value = cpu_to_le64(dev_root);
1073         __dm_bless_for_disk(&value);
1074         r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
1075         if (r) {
1076                 dm_btree_del(&pmd->bl_info, dev_root);
1077                 return r;
1078         }
1079
1080         r = __open_device(pmd, dev, 1, &td);
1081         if (r) {
1082                 dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1083                 dm_btree_del(&pmd->bl_info, dev_root);
1084                 return r;
1085         }
1086         __close_device(td);
1087
1088         return r;
1089 }
1090
1091 int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev)
1092 {
1093         int r = -EINVAL;
1094
1095         pmd_write_lock(pmd);
1096         if (!pmd->fail_io)
1097                 r = __create_thin(pmd, dev);
1098         pmd_write_unlock(pmd);
1099
1100         return r;
1101 }
1102
1103 static int __set_snapshot_details(struct dm_pool_metadata *pmd,
1104                                   struct dm_thin_device *snap,
1105                                   dm_thin_id origin, uint32_t time)
1106 {
1107         int r;
1108         struct dm_thin_device *td;
1109
1110         r = __open_device(pmd, origin, 0, &td);
1111         if (r)
1112                 return r;
1113
1114         td->changed = true;
1115         td->snapshotted_time = time;
1116
1117         snap->mapped_blocks = td->mapped_blocks;
1118         snap->snapshotted_time = time;
1119         __close_device(td);
1120
1121         return 0;
1122 }
1123
1124 static int __create_snap(struct dm_pool_metadata *pmd,
1125                          dm_thin_id dev, dm_thin_id origin)
1126 {
1127         int r;
1128         dm_block_t origin_root;
1129         uint64_t key = origin, dev_key = dev;
1130         struct dm_thin_device *td;
1131         __le64 value;
1132
1133         /* check this device is unused */
1134         r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
1135                             &dev_key, NULL);
1136         if (!r)
1137                 return -EEXIST;
1138
1139         /* find the mapping tree for the origin */
1140         r = dm_btree_lookup(&pmd->tl_info, pmd->root, &key, &value);
1141         if (r)
1142                 return r;
1143         origin_root = le64_to_cpu(value);
1144
1145         /* clone the origin, an inc will do */
1146         dm_tm_inc(pmd->tm, origin_root);
1147
1148         /* insert into the main mapping tree */
1149         value = cpu_to_le64(origin_root);
1150         __dm_bless_for_disk(&value);
1151         key = dev;
1152         r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
1153         if (r) {
1154                 dm_tm_dec(pmd->tm, origin_root);
1155                 return r;
1156         }
1157
1158         pmd->time++;
1159
1160         r = __open_device(pmd, dev, 1, &td);
1161         if (r)
1162                 goto bad;
1163
1164         r = __set_snapshot_details(pmd, td, origin, pmd->time);
1165         __close_device(td);
1166
1167         if (r)
1168                 goto bad;
1169
1170         return 0;
1171
1172 bad:
1173         dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1174         dm_btree_remove(&pmd->details_info, pmd->details_root,
1175                         &key, &pmd->details_root);
1176         return r;
1177 }
1178
1179 int dm_pool_create_snap(struct dm_pool_metadata *pmd,
1180                                  dm_thin_id dev,
1181                                  dm_thin_id origin)
1182 {
1183         int r = -EINVAL;
1184
1185         pmd_write_lock(pmd);
1186         if (!pmd->fail_io)
1187                 r = __create_snap(pmd, dev, origin);
1188         pmd_write_unlock(pmd);
1189
1190         return r;
1191 }
1192
1193 static int __delete_device(struct dm_pool_metadata *pmd, dm_thin_id dev)
1194 {
1195         int r;
1196         uint64_t key = dev;
1197         struct dm_thin_device *td;
1198
1199         /* TODO: failure should mark the transaction invalid */
1200         r = __open_device(pmd, dev, 0, &td);
1201         if (r)
1202                 return r;
1203
1204         if (td->open_count > 1) {
1205                 __close_device(td);
1206                 return -EBUSY;
1207         }
1208
1209         list_del(&td->list);
1210         kfree(td);
1211         r = dm_btree_remove(&pmd->details_info, pmd->details_root,
1212                             &key, &pmd->details_root);
1213         if (r)
1214                 return r;
1215
1216         r = dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1217         if (r)
1218                 return r;
1219
1220         return 0;
1221 }
1222
1223 int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd,
1224                                dm_thin_id dev)
1225 {
1226         int r = -EINVAL;
1227
1228         pmd_write_lock(pmd);
1229         if (!pmd->fail_io)
1230                 r = __delete_device(pmd, dev);
1231         pmd_write_unlock(pmd);
1232
1233         return r;
1234 }
1235
1236 int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
1237                                         uint64_t current_id,
1238                                         uint64_t new_id)
1239 {
1240         int r = -EINVAL;
1241
1242         pmd_write_lock(pmd);
1243
1244         if (pmd->fail_io)
1245                 goto out;
1246
1247         if (pmd->trans_id != current_id) {
1248                 DMERR("mismatched transaction id");
1249                 goto out;
1250         }
1251
1252         pmd->trans_id = new_id;
1253         r = 0;
1254
1255 out:
1256         pmd_write_unlock(pmd);
1257
1258         return r;
1259 }
1260
1261 int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
1262                                         uint64_t *result)
1263 {
1264         int r = -EINVAL;
1265
1266         down_read(&pmd->root_lock);
1267         if (!pmd->fail_io) {
1268                 *result = pmd->trans_id;
1269                 r = 0;
1270         }
1271         up_read(&pmd->root_lock);
1272
1273         return r;
1274 }
1275
1276 static int __reserve_metadata_snap(struct dm_pool_metadata *pmd)
1277 {
1278         int r, inc;
1279         struct thin_disk_superblock *disk_super;
1280         struct dm_block *copy, *sblock;
1281         dm_block_t held_root;
1282
1283         /*
1284          * We commit to ensure the btree roots which we increment in a
1285          * moment are up to date.
1286          */
1287         r = __commit_transaction(pmd);
1288         if (r < 0) {
1289                 DMWARN("%s: __commit_transaction() failed, error = %d",
1290                        __func__, r);
1291                 return r;
1292         }
1293
1294         /*
1295          * Copy the superblock.
1296          */
1297         dm_sm_inc_block(pmd->metadata_sm, THIN_SUPERBLOCK_LOCATION);
1298         r = dm_tm_shadow_block(pmd->tm, THIN_SUPERBLOCK_LOCATION,
1299                                &sb_validator, &copy, &inc);
1300         if (r)
1301                 return r;
1302
1303         BUG_ON(!inc);
1304
1305         held_root = dm_block_location(copy);
1306         disk_super = dm_block_data(copy);
1307
1308         if (le64_to_cpu(disk_super->held_root)) {
1309                 DMWARN("Pool metadata snapshot already exists: release this before taking another.");
1310
1311                 dm_tm_dec(pmd->tm, held_root);
1312                 dm_tm_unlock(pmd->tm, copy);
1313                 return -EBUSY;
1314         }
1315
1316         /*
1317          * Wipe the spacemap since we're not publishing this.
1318          */
1319         memset(&disk_super->data_space_map_root, 0,
1320                sizeof(disk_super->data_space_map_root));
1321         memset(&disk_super->metadata_space_map_root, 0,
1322                sizeof(disk_super->metadata_space_map_root));
1323
1324         /*
1325          * Increment the data structures that need to be preserved.
1326          */
1327         dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->data_mapping_root));
1328         dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->device_details_root));
1329         dm_tm_unlock(pmd->tm, copy);
1330
1331         /*
1332          * Write the held root into the superblock.
1333          */
1334         r = superblock_lock(pmd, &sblock);
1335         if (r) {
1336                 dm_tm_dec(pmd->tm, held_root);
1337                 return r;
1338         }
1339
1340         disk_super = dm_block_data(sblock);
1341         disk_super->held_root = cpu_to_le64(held_root);
1342         dm_bm_unlock(sblock);
1343         return 0;
1344 }
1345
1346 int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd)
1347 {
1348         int r = -EINVAL;
1349
1350         pmd_write_lock(pmd);
1351         if (!pmd->fail_io)
1352                 r = __reserve_metadata_snap(pmd);
1353         pmd_write_unlock(pmd);
1354
1355         return r;
1356 }
1357
1358 static int __release_metadata_snap(struct dm_pool_metadata *pmd)
1359 {
1360         int r;
1361         struct thin_disk_superblock *disk_super;
1362         struct dm_block *sblock, *copy;
1363         dm_block_t held_root;
1364
1365         r = superblock_lock(pmd, &sblock);
1366         if (r)
1367                 return r;
1368
1369         disk_super = dm_block_data(sblock);
1370         held_root = le64_to_cpu(disk_super->held_root);
1371         disk_super->held_root = cpu_to_le64(0);
1372
1373         dm_bm_unlock(sblock);
1374
1375         if (!held_root) {
1376                 DMWARN("No pool metadata snapshot found: nothing to release.");
1377                 return -EINVAL;
1378         }
1379
1380         r = dm_tm_read_lock(pmd->tm, held_root, &sb_validator, &copy);
1381         if (r)
1382                 return r;
1383
1384         disk_super = dm_block_data(copy);
1385         dm_btree_del(&pmd->info, le64_to_cpu(disk_super->data_mapping_root));
1386         dm_btree_del(&pmd->details_info, le64_to_cpu(disk_super->device_details_root));
1387         dm_sm_dec_block(pmd->metadata_sm, held_root);
1388
1389         dm_tm_unlock(pmd->tm, copy);
1390
1391         return 0;
1392 }
1393
1394 int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd)
1395 {
1396         int r = -EINVAL;
1397
1398         pmd_write_lock(pmd);
1399         if (!pmd->fail_io)
1400                 r = __release_metadata_snap(pmd);
1401         pmd_write_unlock(pmd);
1402
1403         return r;
1404 }
1405
1406 static int __get_metadata_snap(struct dm_pool_metadata *pmd,
1407                                dm_block_t *result)
1408 {
1409         int r;
1410         struct thin_disk_superblock *disk_super;
1411         struct dm_block *sblock;
1412
1413         r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
1414                             &sb_validator, &sblock);
1415         if (r)
1416                 return r;
1417
1418         disk_super = dm_block_data(sblock);
1419         *result = le64_to_cpu(disk_super->held_root);
1420
1421         dm_bm_unlock(sblock);
1422
1423         return 0;
1424 }
1425
1426 int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd,
1427                               dm_block_t *result)
1428 {
1429         int r = -EINVAL;
1430
1431         down_read(&pmd->root_lock);
1432         if (!pmd->fail_io)
1433                 r = __get_metadata_snap(pmd, result);
1434         up_read(&pmd->root_lock);
1435
1436         return r;
1437 }
1438
1439 int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
1440                              struct dm_thin_device **td)
1441 {
1442         int r = -EINVAL;
1443
1444         pmd_write_lock_in_core(pmd);
1445         if (!pmd->fail_io)
1446                 r = __open_device(pmd, dev, 0, td);
1447         pmd_write_unlock(pmd);
1448
1449         return r;
1450 }
1451
1452 int dm_pool_close_thin_device(struct dm_thin_device *td)
1453 {
1454         pmd_write_lock_in_core(td->pmd);
1455         __close_device(td);
1456         pmd_write_unlock(td->pmd);
1457
1458         return 0;
1459 }
1460
1461 dm_thin_id dm_thin_dev_id(struct dm_thin_device *td)
1462 {
1463         return td->id;
1464 }
1465
1466 /*
1467  * Check whether @time (of block creation) is older than @td's last snapshot.
1468  * If so then the associated block is shared with the last snapshot device.
1469  * Any block on a device created *after* the device last got snapshotted is
1470  * necessarily not shared.
1471  */
1472 static bool __snapshotted_since(struct dm_thin_device *td, uint32_t time)
1473 {
1474         return td->snapshotted_time > time;
1475 }
1476
1477 static void unpack_lookup_result(struct dm_thin_device *td, __le64 value,
1478                                  struct dm_thin_lookup_result *result)
1479 {
1480         uint64_t block_time = 0;
1481         dm_block_t exception_block;
1482         uint32_t exception_time;
1483
1484         block_time = le64_to_cpu(value);
1485         unpack_block_time(block_time, &exception_block, &exception_time);
1486         result->block = exception_block;
1487         result->shared = __snapshotted_since(td, exception_time);
1488 }
1489
1490 static int __find_block(struct dm_thin_device *td, dm_block_t block,
1491                         int can_issue_io, struct dm_thin_lookup_result *result)
1492 {
1493         int r;
1494         __le64 value;
1495         struct dm_pool_metadata *pmd = td->pmd;
1496         dm_block_t keys[2] = { td->id, block };
1497         struct dm_btree_info *info;
1498
1499         if (can_issue_io) {
1500                 info = &pmd->info;
1501         } else
1502                 info = &pmd->nb_info;
1503
1504         r = dm_btree_lookup(info, pmd->root, keys, &value);
1505         if (!r)
1506                 unpack_lookup_result(td, value, result);
1507
1508         return r;
1509 }
1510
1511 int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
1512                        int can_issue_io, struct dm_thin_lookup_result *result)
1513 {
1514         int r;
1515         struct dm_pool_metadata *pmd = td->pmd;
1516
1517         down_read(&pmd->root_lock);
1518         if (pmd->fail_io) {
1519                 up_read(&pmd->root_lock);
1520                 return -EINVAL;
1521         }
1522
1523         r = __find_block(td, block, can_issue_io, result);
1524
1525         up_read(&pmd->root_lock);
1526         return r;
1527 }
1528
1529 static int __find_next_mapped_block(struct dm_thin_device *td, dm_block_t block,
1530                                           dm_block_t *vblock,
1531                                           struct dm_thin_lookup_result *result)
1532 {
1533         int r;
1534         __le64 value;
1535         struct dm_pool_metadata *pmd = td->pmd;
1536         dm_block_t keys[2] = { td->id, block };
1537
1538         r = dm_btree_lookup_next(&pmd->info, pmd->root, keys, vblock, &value);
1539         if (!r)
1540                 unpack_lookup_result(td, value, result);
1541
1542         return r;
1543 }
1544
1545 static int __find_mapped_range(struct dm_thin_device *td,
1546                                dm_block_t begin, dm_block_t end,
1547                                dm_block_t *thin_begin, dm_block_t *thin_end,
1548                                dm_block_t *pool_begin, bool *maybe_shared)
1549 {
1550         int r;
1551         dm_block_t pool_end;
1552         struct dm_thin_lookup_result lookup;
1553
1554         if (end < begin)
1555                 return -ENODATA;
1556
1557         r = __find_next_mapped_block(td, begin, &begin, &lookup);
1558         if (r)
1559                 return r;
1560
1561         if (begin >= end)
1562                 return -ENODATA;
1563
1564         *thin_begin = begin;
1565         *pool_begin = lookup.block;
1566         *maybe_shared = lookup.shared;
1567
1568         begin++;
1569         pool_end = *pool_begin + 1;
1570         while (begin != end) {
1571                 r = __find_block(td, begin, true, &lookup);
1572                 if (r) {
1573                         if (r == -ENODATA)
1574                                 break;
1575                         else
1576                                 return r;
1577                 }
1578
1579                 if ((lookup.block != pool_end) ||
1580                     (lookup.shared != *maybe_shared))
1581                         break;
1582
1583                 pool_end++;
1584                 begin++;
1585         }
1586
1587         *thin_end = begin;
1588         return 0;
1589 }
1590
1591 int dm_thin_find_mapped_range(struct dm_thin_device *td,
1592                               dm_block_t begin, dm_block_t end,
1593                               dm_block_t *thin_begin, dm_block_t *thin_end,
1594                               dm_block_t *pool_begin, bool *maybe_shared)
1595 {
1596         int r = -EINVAL;
1597         struct dm_pool_metadata *pmd = td->pmd;
1598
1599         down_read(&pmd->root_lock);
1600         if (!pmd->fail_io) {
1601                 r = __find_mapped_range(td, begin, end, thin_begin, thin_end,
1602                                         pool_begin, maybe_shared);
1603         }
1604         up_read(&pmd->root_lock);
1605
1606         return r;
1607 }
1608
1609 static int __insert(struct dm_thin_device *td, dm_block_t block,
1610                     dm_block_t data_block)
1611 {
1612         int r, inserted;
1613         __le64 value;
1614         struct dm_pool_metadata *pmd = td->pmd;
1615         dm_block_t keys[2] = { td->id, block };
1616
1617         value = cpu_to_le64(pack_block_time(data_block, pmd->time));
1618         __dm_bless_for_disk(&value);
1619
1620         r = dm_btree_insert_notify(&pmd->info, pmd->root, keys, &value,
1621                                    &pmd->root, &inserted);
1622         if (r)
1623                 return r;
1624
1625         td->changed = true;
1626         if (inserted)
1627                 td->mapped_blocks++;
1628
1629         return 0;
1630 }
1631
1632 int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
1633                          dm_block_t data_block)
1634 {
1635         int r = -EINVAL;
1636
1637         pmd_write_lock(td->pmd);
1638         if (!td->pmd->fail_io)
1639                 r = __insert(td, block, data_block);
1640         pmd_write_unlock(td->pmd);
1641
1642         return r;
1643 }
1644
1645 static int __remove(struct dm_thin_device *td, dm_block_t block)
1646 {
1647         int r;
1648         struct dm_pool_metadata *pmd = td->pmd;
1649         dm_block_t keys[2] = { td->id, block };
1650
1651         r = dm_btree_remove(&pmd->info, pmd->root, keys, &pmd->root);
1652         if (r)
1653                 return r;
1654
1655         td->mapped_blocks--;
1656         td->changed = true;
1657
1658         return 0;
1659 }
1660
1661 static int __remove_range(struct dm_thin_device *td, dm_block_t begin, dm_block_t end)
1662 {
1663         int r;
1664         unsigned count, total_count = 0;
1665         struct dm_pool_metadata *pmd = td->pmd;
1666         dm_block_t keys[1] = { td->id };
1667         __le64 value;
1668         dm_block_t mapping_root;
1669
1670         /*
1671          * Find the mapping tree
1672          */
1673         r = dm_btree_lookup(&pmd->tl_info, pmd->root, keys, &value);
1674         if (r)
1675                 return r;
1676
1677         /*
1678          * Remove from the mapping tree, taking care to inc the
1679          * ref count so it doesn't get deleted.
1680          */
1681         mapping_root = le64_to_cpu(value);
1682         dm_tm_inc(pmd->tm, mapping_root);
1683         r = dm_btree_remove(&pmd->tl_info, pmd->root, keys, &pmd->root);
1684         if (r)
1685                 return r;
1686
1687         /*
1688          * Remove leaves stops at the first unmapped entry, so we have to
1689          * loop round finding mapped ranges.
1690          */
1691         while (begin < end) {
1692                 r = dm_btree_lookup_next(&pmd->bl_info, mapping_root, &begin, &begin, &value);
1693                 if (r == -ENODATA)
1694                         break;
1695
1696                 if (r)
1697                         return r;
1698
1699                 if (begin >= end)
1700                         break;
1701
1702                 r = dm_btree_remove_leaves(&pmd->bl_info, mapping_root, &begin, end, &mapping_root, &count);
1703                 if (r)
1704                         return r;
1705
1706                 total_count += count;
1707         }
1708
1709         td->mapped_blocks -= total_count;
1710         td->changed = true;
1711
1712         /*
1713          * Reinsert the mapping tree.
1714          */
1715         value = cpu_to_le64(mapping_root);
1716         __dm_bless_for_disk(&value);
1717         return dm_btree_insert(&pmd->tl_info, pmd->root, keys, &value, &pmd->root);
1718 }
1719
1720 int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block)
1721 {
1722         int r = -EINVAL;
1723
1724         pmd_write_lock(td->pmd);
1725         if (!td->pmd->fail_io)
1726                 r = __remove(td, block);
1727         pmd_write_unlock(td->pmd);
1728
1729         return r;
1730 }
1731
1732 int dm_thin_remove_range(struct dm_thin_device *td,
1733                          dm_block_t begin, dm_block_t end)
1734 {
1735         int r = -EINVAL;
1736
1737         pmd_write_lock(td->pmd);
1738         if (!td->pmd->fail_io)
1739                 r = __remove_range(td, begin, end);
1740         pmd_write_unlock(td->pmd);
1741
1742         return r;
1743 }
1744
1745 int dm_pool_block_is_shared(struct dm_pool_metadata *pmd, dm_block_t b, bool *result)
1746 {
1747         int r;
1748         uint32_t ref_count;
1749
1750         down_read(&pmd->root_lock);
1751         r = dm_sm_get_count(pmd->data_sm, b, &ref_count);
1752         if (!r)
1753                 *result = (ref_count > 1);
1754         up_read(&pmd->root_lock);
1755
1756         return r;
1757 }
1758
1759 int dm_pool_inc_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e)
1760 {
1761         int r = 0;
1762
1763         pmd_write_lock(pmd);
1764         for (; b != e; b++) {
1765                 r = dm_sm_inc_block(pmd->data_sm, b);
1766                 if (r)
1767                         break;
1768         }
1769         pmd_write_unlock(pmd);
1770
1771         return r;
1772 }
1773
1774 int dm_pool_dec_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e)
1775 {
1776         int r = 0;
1777
1778         pmd_write_lock(pmd);
1779         for (; b != e; b++) {
1780                 r = dm_sm_dec_block(pmd->data_sm, b);
1781                 if (r)
1782                         break;
1783         }
1784         pmd_write_unlock(pmd);
1785
1786         return r;
1787 }
1788
1789 bool dm_thin_changed_this_transaction(struct dm_thin_device *td)
1790 {
1791         int r;
1792
1793         down_read(&td->pmd->root_lock);
1794         r = td->changed;
1795         up_read(&td->pmd->root_lock);
1796
1797         return r;
1798 }
1799
1800 bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd)
1801 {
1802         bool r = false;
1803         struct dm_thin_device *td, *tmp;
1804
1805         down_read(&pmd->root_lock);
1806         list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
1807                 if (td->changed) {
1808                         r = td->changed;
1809                         break;
1810                 }
1811         }
1812         up_read(&pmd->root_lock);
1813
1814         return r;
1815 }
1816
1817 bool dm_thin_aborted_changes(struct dm_thin_device *td)
1818 {
1819         bool r;
1820
1821         down_read(&td->pmd->root_lock);
1822         r = td->aborted_with_changes;
1823         up_read(&td->pmd->root_lock);
1824
1825         return r;
1826 }
1827
1828 int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result)
1829 {
1830         int r = -EINVAL;
1831
1832         pmd_write_lock(pmd);
1833         if (!pmd->fail_io)
1834                 r = dm_sm_new_block(pmd->data_sm, result);
1835         pmd_write_unlock(pmd);
1836
1837         return r;
1838 }
1839
1840 int dm_pool_commit_metadata(struct dm_pool_metadata *pmd)
1841 {
1842         int r = -EINVAL;
1843
1844         /*
1845          * Care is taken to not have commit be what
1846          * triggers putting the thin-pool in-service.
1847          */
1848         pmd_write_lock_in_core(pmd);
1849         if (pmd->fail_io)
1850                 goto out;
1851
1852         r = __commit_transaction(pmd);
1853         if (r < 0)
1854                 goto out;
1855
1856         /*
1857          * Open the next transaction.
1858          */
1859         r = __begin_transaction(pmd);
1860 out:
1861         pmd_write_unlock(pmd);
1862         return r;
1863 }
1864
1865 static void __set_abort_with_changes_flags(struct dm_pool_metadata *pmd)
1866 {
1867         struct dm_thin_device *td;
1868
1869         list_for_each_entry(td, &pmd->thin_devices, list)
1870                 td->aborted_with_changes = td->changed;
1871 }
1872
1873 int dm_pool_abort_metadata(struct dm_pool_metadata *pmd)
1874 {
1875         int r = -EINVAL;
1876
1877         pmd_write_lock(pmd);
1878         if (pmd->fail_io)
1879                 goto out;
1880
1881         __set_abort_with_changes_flags(pmd);
1882         __destroy_persistent_data_objects(pmd);
1883         r = __create_persistent_data_objects(pmd, false);
1884         if (r)
1885                 pmd->fail_io = true;
1886
1887 out:
1888         pmd_write_unlock(pmd);
1889
1890         return r;
1891 }
1892
1893 int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, dm_block_t *result)
1894 {
1895         int r = -EINVAL;
1896
1897         down_read(&pmd->root_lock);
1898         if (!pmd->fail_io)
1899                 r = dm_sm_get_nr_free(pmd->data_sm, result);
1900         up_read(&pmd->root_lock);
1901
1902         return r;
1903 }
1904
1905 int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
1906                                           dm_block_t *result)
1907 {
1908         int r = -EINVAL;
1909
1910         down_read(&pmd->root_lock);
1911         if (!pmd->fail_io)
1912                 r = dm_sm_get_nr_free(pmd->metadata_sm, result);
1913
1914         if (!r) {
1915                 if (*result < pmd->metadata_reserve)
1916                         *result = 0;
1917                 else
1918                         *result -= pmd->metadata_reserve;
1919         }
1920         up_read(&pmd->root_lock);
1921
1922         return r;
1923 }
1924
1925 int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
1926                                   dm_block_t *result)
1927 {
1928         int r = -EINVAL;
1929
1930         down_read(&pmd->root_lock);
1931         if (!pmd->fail_io)
1932                 r = dm_sm_get_nr_blocks(pmd->metadata_sm, result);
1933         up_read(&pmd->root_lock);
1934
1935         return r;
1936 }
1937
1938 int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result)
1939 {
1940         int r = -EINVAL;
1941
1942         down_read(&pmd->root_lock);
1943         if (!pmd->fail_io)
1944                 r = dm_sm_get_nr_blocks(pmd->data_sm, result);
1945         up_read(&pmd->root_lock);
1946
1947         return r;
1948 }
1949
1950 int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result)
1951 {
1952         int r = -EINVAL;
1953         struct dm_pool_metadata *pmd = td->pmd;
1954
1955         down_read(&pmd->root_lock);
1956         if (!pmd->fail_io) {
1957                 *result = td->mapped_blocks;
1958                 r = 0;
1959         }
1960         up_read(&pmd->root_lock);
1961
1962         return r;
1963 }
1964
1965 static int __highest_block(struct dm_thin_device *td, dm_block_t *result)
1966 {
1967         int r;
1968         __le64 value_le;
1969         dm_block_t thin_root;
1970         struct dm_pool_metadata *pmd = td->pmd;
1971
1972         r = dm_btree_lookup(&pmd->tl_info, pmd->root, &td->id, &value_le);
1973         if (r)
1974                 return r;
1975
1976         thin_root = le64_to_cpu(value_le);
1977
1978         return dm_btree_find_highest_key(&pmd->bl_info, thin_root, result);
1979 }
1980
1981 int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
1982                                      dm_block_t *result)
1983 {
1984         int r = -EINVAL;
1985         struct dm_pool_metadata *pmd = td->pmd;
1986
1987         down_read(&pmd->root_lock);
1988         if (!pmd->fail_io)
1989                 r = __highest_block(td, result);
1990         up_read(&pmd->root_lock);
1991
1992         return r;
1993 }
1994
1995 static int __resize_space_map(struct dm_space_map *sm, dm_block_t new_count)
1996 {
1997         int r;
1998         dm_block_t old_count;
1999
2000         r = dm_sm_get_nr_blocks(sm, &old_count);
2001         if (r)
2002                 return r;
2003
2004         if (new_count == old_count)
2005                 return 0;
2006
2007         if (new_count < old_count) {
2008                 DMERR("cannot reduce size of space map");
2009                 return -EINVAL;
2010         }
2011
2012         return dm_sm_extend(sm, new_count - old_count);
2013 }
2014
2015 int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
2016 {
2017         int r = -EINVAL;
2018
2019         pmd_write_lock(pmd);
2020         if (!pmd->fail_io)
2021                 r = __resize_space_map(pmd->data_sm, new_count);
2022         pmd_write_unlock(pmd);
2023
2024         return r;
2025 }
2026
2027 int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
2028 {
2029         int r = -EINVAL;
2030
2031         pmd_write_lock(pmd);
2032         if (!pmd->fail_io) {
2033                 r = __resize_space_map(pmd->metadata_sm, new_count);
2034                 if (!r)
2035                         __set_metadata_reserve(pmd);
2036         }
2037         pmd_write_unlock(pmd);
2038
2039         return r;
2040 }
2041
2042 void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd)
2043 {
2044         pmd_write_lock_in_core(pmd);
2045         dm_bm_set_read_only(pmd->bm);
2046         pmd_write_unlock(pmd);
2047 }
2048
2049 void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd)
2050 {
2051         pmd_write_lock_in_core(pmd);
2052         dm_bm_set_read_write(pmd->bm);
2053         pmd_write_unlock(pmd);
2054 }
2055
2056 int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd,
2057                                         dm_block_t threshold,
2058                                         dm_sm_threshold_fn fn,
2059                                         void *context)
2060 {
2061         int r;
2062
2063         pmd_write_lock_in_core(pmd);
2064         r = dm_sm_register_threshold_callback(pmd->metadata_sm, threshold, fn, context);
2065         pmd_write_unlock(pmd);
2066
2067         return r;
2068 }
2069
2070 void dm_pool_register_pre_commit_callback(struct dm_pool_metadata *pmd,
2071                                           dm_pool_pre_commit_fn fn,
2072                                           void *context)
2073 {
2074         pmd_write_lock_in_core(pmd);
2075         pmd->pre_commit_fn = fn;
2076         pmd->pre_commit_context = context;
2077         pmd_write_unlock(pmd);
2078 }
2079
2080 int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd)
2081 {
2082         int r = -EINVAL;
2083         struct dm_block *sblock;
2084         struct thin_disk_superblock *disk_super;
2085
2086         pmd_write_lock(pmd);
2087         if (pmd->fail_io)
2088                 goto out;
2089
2090         pmd->flags |= THIN_METADATA_NEEDS_CHECK_FLAG;
2091
2092         r = superblock_lock(pmd, &sblock);
2093         if (r) {
2094                 DMERR("couldn't lock superblock");
2095                 goto out;
2096         }
2097
2098         disk_super = dm_block_data(sblock);
2099         disk_super->flags = cpu_to_le32(pmd->flags);
2100
2101         dm_bm_unlock(sblock);
2102 out:
2103         pmd_write_unlock(pmd);
2104         return r;
2105 }
2106
2107 bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd)
2108 {
2109         bool needs_check;
2110
2111         down_read(&pmd->root_lock);
2112         needs_check = pmd->flags & THIN_METADATA_NEEDS_CHECK_FLAG;
2113         up_read(&pmd->root_lock);
2114
2115         return needs_check;
2116 }
2117
2118 void dm_pool_issue_prefetches(struct dm_pool_metadata *pmd)
2119 {
2120         down_read(&pmd->root_lock);
2121         if (!pmd->fail_io)
2122                 dm_tm_issue_prefetches(pmd->tm);
2123         up_read(&pmd->root_lock);
2124 }