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 (get_disk_ro(pmd->bdev->bd_disk))
 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 disk_device_details details_le;
1055         struct dm_thin_device *td;
1056         __le64 value;
1057
1058         r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
1059                             &key, &details_le);
1060         if (!r)
1061                 return -EEXIST;
1062
1063         /*
1064          * Create an empty btree for the mappings.
1065          */
1066         r = dm_btree_empty(&pmd->bl_info, &dev_root);
1067         if (r)
1068                 return r;
1069
1070         /*
1071          * Insert it into the main mapping tree.
1072          */
1073         value = cpu_to_le64(dev_root);
1074         __dm_bless_for_disk(&value);
1075         r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
1076         if (r) {
1077                 dm_btree_del(&pmd->bl_info, dev_root);
1078                 return r;
1079         }
1080
1081         r = __open_device(pmd, dev, 1, &td);
1082         if (r) {
1083                 dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1084                 dm_btree_del(&pmd->bl_info, dev_root);
1085                 return r;
1086         }
1087         __close_device(td);
1088
1089         return r;
1090 }
1091
1092 int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev)
1093 {
1094         int r = -EINVAL;
1095
1096         pmd_write_lock(pmd);
1097         if (!pmd->fail_io)
1098                 r = __create_thin(pmd, dev);
1099         pmd_write_unlock(pmd);
1100
1101         return r;
1102 }
1103
1104 static int __set_snapshot_details(struct dm_pool_metadata *pmd,
1105                                   struct dm_thin_device *snap,
1106                                   dm_thin_id origin, uint32_t time)
1107 {
1108         int r;
1109         struct dm_thin_device *td;
1110
1111         r = __open_device(pmd, origin, 0, &td);
1112         if (r)
1113                 return r;
1114
1115         td->changed = true;
1116         td->snapshotted_time = time;
1117
1118         snap->mapped_blocks = td->mapped_blocks;
1119         snap->snapshotted_time = time;
1120         __close_device(td);
1121
1122         return 0;
1123 }
1124
1125 static int __create_snap(struct dm_pool_metadata *pmd,
1126                          dm_thin_id dev, dm_thin_id origin)
1127 {
1128         int r;
1129         dm_block_t origin_root;
1130         uint64_t key = origin, dev_key = dev;
1131         struct dm_thin_device *td;
1132         struct disk_device_details details_le;
1133         __le64 value;
1134
1135         /* check this device is unused */
1136         r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
1137                             &dev_key, &details_le);
1138         if (!r)
1139                 return -EEXIST;
1140
1141         /* find the mapping tree for the origin */
1142         r = dm_btree_lookup(&pmd->tl_info, pmd->root, &key, &value);
1143         if (r)
1144                 return r;
1145         origin_root = le64_to_cpu(value);
1146
1147         /* clone the origin, an inc will do */
1148         dm_tm_inc(pmd->tm, origin_root);
1149
1150         /* insert into the main mapping tree */
1151         value = cpu_to_le64(origin_root);
1152         __dm_bless_for_disk(&value);
1153         key = dev;
1154         r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
1155         if (r) {
1156                 dm_tm_dec(pmd->tm, origin_root);
1157                 return r;
1158         }
1159
1160         pmd->time++;
1161
1162         r = __open_device(pmd, dev, 1, &td);
1163         if (r)
1164                 goto bad;
1165
1166         r = __set_snapshot_details(pmd, td, origin, pmd->time);
1167         __close_device(td);
1168
1169         if (r)
1170                 goto bad;
1171
1172         return 0;
1173
1174 bad:
1175         dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1176         dm_btree_remove(&pmd->details_info, pmd->details_root,
1177                         &key, &pmd->details_root);
1178         return r;
1179 }
1180
1181 int dm_pool_create_snap(struct dm_pool_metadata *pmd,
1182                                  dm_thin_id dev,
1183                                  dm_thin_id origin)
1184 {
1185         int r = -EINVAL;
1186
1187         pmd_write_lock(pmd);
1188         if (!pmd->fail_io)
1189                 r = __create_snap(pmd, dev, origin);
1190         pmd_write_unlock(pmd);
1191
1192         return r;
1193 }
1194
1195 static int __delete_device(struct dm_pool_metadata *pmd, dm_thin_id dev)
1196 {
1197         int r;
1198         uint64_t key = dev;
1199         struct dm_thin_device *td;
1200
1201         /* TODO: failure should mark the transaction invalid */
1202         r = __open_device(pmd, dev, 0, &td);
1203         if (r)
1204                 return r;
1205
1206         if (td->open_count > 1) {
1207                 __close_device(td);
1208                 return -EBUSY;
1209         }
1210
1211         list_del(&td->list);
1212         kfree(td);
1213         r = dm_btree_remove(&pmd->details_info, pmd->details_root,
1214                             &key, &pmd->details_root);
1215         if (r)
1216                 return r;
1217
1218         r = dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1219         if (r)
1220                 return r;
1221
1222         return 0;
1223 }
1224
1225 int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd,
1226                                dm_thin_id dev)
1227 {
1228         int r = -EINVAL;
1229
1230         pmd_write_lock(pmd);
1231         if (!pmd->fail_io)
1232                 r = __delete_device(pmd, dev);
1233         pmd_write_unlock(pmd);
1234
1235         return r;
1236 }
1237
1238 int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
1239                                         uint64_t current_id,
1240                                         uint64_t new_id)
1241 {
1242         int r = -EINVAL;
1243
1244         pmd_write_lock(pmd);
1245
1246         if (pmd->fail_io)
1247                 goto out;
1248
1249         if (pmd->trans_id != current_id) {
1250                 DMERR("mismatched transaction id");
1251                 goto out;
1252         }
1253
1254         pmd->trans_id = new_id;
1255         r = 0;
1256
1257 out:
1258         pmd_write_unlock(pmd);
1259
1260         return r;
1261 }
1262
1263 int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
1264                                         uint64_t *result)
1265 {
1266         int r = -EINVAL;
1267
1268         down_read(&pmd->root_lock);
1269         if (!pmd->fail_io) {
1270                 *result = pmd->trans_id;
1271                 r = 0;
1272         }
1273         up_read(&pmd->root_lock);
1274
1275         return r;
1276 }
1277
1278 static int __reserve_metadata_snap(struct dm_pool_metadata *pmd)
1279 {
1280         int r, inc;
1281         struct thin_disk_superblock *disk_super;
1282         struct dm_block *copy, *sblock;
1283         dm_block_t held_root;
1284
1285         /*
1286          * We commit to ensure the btree roots which we increment in a
1287          * moment are up to date.
1288          */
1289         r = __commit_transaction(pmd);
1290         if (r < 0) {
1291                 DMWARN("%s: __commit_transaction() failed, error = %d",
1292                        __func__, r);
1293                 return r;
1294         }
1295
1296         /*
1297          * Copy the superblock.
1298          */
1299         dm_sm_inc_block(pmd->metadata_sm, THIN_SUPERBLOCK_LOCATION);
1300         r = dm_tm_shadow_block(pmd->tm, THIN_SUPERBLOCK_LOCATION,
1301                                &sb_validator, &copy, &inc);
1302         if (r)
1303                 return r;
1304
1305         BUG_ON(!inc);
1306
1307         held_root = dm_block_location(copy);
1308         disk_super = dm_block_data(copy);
1309
1310         if (le64_to_cpu(disk_super->held_root)) {
1311                 DMWARN("Pool metadata snapshot already exists: release this before taking another.");
1312
1313                 dm_tm_dec(pmd->tm, held_root);
1314                 dm_tm_unlock(pmd->tm, copy);
1315                 return -EBUSY;
1316         }
1317
1318         /*
1319          * Wipe the spacemap since we're not publishing this.
1320          */
1321         memset(&disk_super->data_space_map_root, 0,
1322                sizeof(disk_super->data_space_map_root));
1323         memset(&disk_super->metadata_space_map_root, 0,
1324                sizeof(disk_super->metadata_space_map_root));
1325
1326         /*
1327          * Increment the data structures that need to be preserved.
1328          */
1329         dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->data_mapping_root));
1330         dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->device_details_root));
1331         dm_tm_unlock(pmd->tm, copy);
1332
1333         /*
1334          * Write the held root into the superblock.
1335          */
1336         r = superblock_lock(pmd, &sblock);
1337         if (r) {
1338                 dm_tm_dec(pmd->tm, held_root);
1339                 return r;
1340         }
1341
1342         disk_super = dm_block_data(sblock);
1343         disk_super->held_root = cpu_to_le64(held_root);
1344         dm_bm_unlock(sblock);
1345         return 0;
1346 }
1347
1348 int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd)
1349 {
1350         int r = -EINVAL;
1351
1352         pmd_write_lock(pmd);
1353         if (!pmd->fail_io)
1354                 r = __reserve_metadata_snap(pmd);
1355         pmd_write_unlock(pmd);
1356
1357         return r;
1358 }
1359
1360 static int __release_metadata_snap(struct dm_pool_metadata *pmd)
1361 {
1362         int r;
1363         struct thin_disk_superblock *disk_super;
1364         struct dm_block *sblock, *copy;
1365         dm_block_t held_root;
1366
1367         r = superblock_lock(pmd, &sblock);
1368         if (r)
1369                 return r;
1370
1371         disk_super = dm_block_data(sblock);
1372         held_root = le64_to_cpu(disk_super->held_root);
1373         disk_super->held_root = cpu_to_le64(0);
1374
1375         dm_bm_unlock(sblock);
1376
1377         if (!held_root) {
1378                 DMWARN("No pool metadata snapshot found: nothing to release.");
1379                 return -EINVAL;
1380         }
1381
1382         r = dm_tm_read_lock(pmd->tm, held_root, &sb_validator, &copy);
1383         if (r)
1384                 return r;
1385
1386         disk_super = dm_block_data(copy);
1387         dm_btree_del(&pmd->info, le64_to_cpu(disk_super->data_mapping_root));
1388         dm_btree_del(&pmd->details_info, le64_to_cpu(disk_super->device_details_root));
1389         dm_sm_dec_block(pmd->metadata_sm, held_root);
1390
1391         dm_tm_unlock(pmd->tm, copy);
1392
1393         return 0;
1394 }
1395
1396 int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd)
1397 {
1398         int r = -EINVAL;
1399
1400         pmd_write_lock(pmd);
1401         if (!pmd->fail_io)
1402                 r = __release_metadata_snap(pmd);
1403         pmd_write_unlock(pmd);
1404
1405         return r;
1406 }
1407
1408 static int __get_metadata_snap(struct dm_pool_metadata *pmd,
1409                                dm_block_t *result)
1410 {
1411         int r;
1412         struct thin_disk_superblock *disk_super;
1413         struct dm_block *sblock;
1414
1415         r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
1416                             &sb_validator, &sblock);
1417         if (r)
1418                 return r;
1419
1420         disk_super = dm_block_data(sblock);
1421         *result = le64_to_cpu(disk_super->held_root);
1422
1423         dm_bm_unlock(sblock);
1424
1425         return 0;
1426 }
1427
1428 int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd,
1429                               dm_block_t *result)
1430 {
1431         int r = -EINVAL;
1432
1433         down_read(&pmd->root_lock);
1434         if (!pmd->fail_io)
1435                 r = __get_metadata_snap(pmd, result);
1436         up_read(&pmd->root_lock);
1437
1438         return r;
1439 }
1440
1441 int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
1442                              struct dm_thin_device **td)
1443 {
1444         int r = -EINVAL;
1445
1446         pmd_write_lock_in_core(pmd);
1447         if (!pmd->fail_io)
1448                 r = __open_device(pmd, dev, 0, td);
1449         pmd_write_unlock(pmd);
1450
1451         return r;
1452 }
1453
1454 int dm_pool_close_thin_device(struct dm_thin_device *td)
1455 {
1456         pmd_write_lock_in_core(td->pmd);
1457         __close_device(td);
1458         pmd_write_unlock(td->pmd);
1459
1460         return 0;
1461 }
1462
1463 dm_thin_id dm_thin_dev_id(struct dm_thin_device *td)
1464 {
1465         return td->id;
1466 }
1467
1468 /*
1469  * Check whether @time (of block creation) is older than @td's last snapshot.
1470  * If so then the associated block is shared with the last snapshot device.
1471  * Any block on a device created *after* the device last got snapshotted is
1472  * necessarily not shared.
1473  */
1474 static bool __snapshotted_since(struct dm_thin_device *td, uint32_t time)
1475 {
1476         return td->snapshotted_time > time;
1477 }
1478
1479 static void unpack_lookup_result(struct dm_thin_device *td, __le64 value,
1480                                  struct dm_thin_lookup_result *result)
1481 {
1482         uint64_t block_time = 0;
1483         dm_block_t exception_block;
1484         uint32_t exception_time;
1485
1486         block_time = le64_to_cpu(value);
1487         unpack_block_time(block_time, &exception_block, &exception_time);
1488         result->block = exception_block;
1489         result->shared = __snapshotted_since(td, exception_time);
1490 }
1491
1492 static int __find_block(struct dm_thin_device *td, dm_block_t block,
1493                         int can_issue_io, struct dm_thin_lookup_result *result)
1494 {
1495         int r;
1496         __le64 value;
1497         struct dm_pool_metadata *pmd = td->pmd;
1498         dm_block_t keys[2] = { td->id, block };
1499         struct dm_btree_info *info;
1500
1501         if (can_issue_io) {
1502                 info = &pmd->info;
1503         } else
1504                 info = &pmd->nb_info;
1505
1506         r = dm_btree_lookup(info, pmd->root, keys, &value);
1507         if (!r)
1508                 unpack_lookup_result(td, value, result);
1509
1510         return r;
1511 }
1512
1513 int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
1514                        int can_issue_io, struct dm_thin_lookup_result *result)
1515 {
1516         int r;
1517         struct dm_pool_metadata *pmd = td->pmd;
1518
1519         down_read(&pmd->root_lock);
1520         if (pmd->fail_io) {
1521                 up_read(&pmd->root_lock);
1522                 return -EINVAL;
1523         }
1524
1525         r = __find_block(td, block, can_issue_io, result);
1526
1527         up_read(&pmd->root_lock);
1528         return r;
1529 }
1530
1531 static int __find_next_mapped_block(struct dm_thin_device *td, dm_block_t block,
1532                                           dm_block_t *vblock,
1533                                           struct dm_thin_lookup_result *result)
1534 {
1535         int r;
1536         __le64 value;
1537         struct dm_pool_metadata *pmd = td->pmd;
1538         dm_block_t keys[2] = { td->id, block };
1539
1540         r = dm_btree_lookup_next(&pmd->info, pmd->root, keys, vblock, &value);
1541         if (!r)
1542                 unpack_lookup_result(td, value, result);
1543
1544         return r;
1545 }
1546
1547 static int __find_mapped_range(struct dm_thin_device *td,
1548                                dm_block_t begin, dm_block_t end,
1549                                dm_block_t *thin_begin, dm_block_t *thin_end,
1550                                dm_block_t *pool_begin, bool *maybe_shared)
1551 {
1552         int r;
1553         dm_block_t pool_end;
1554         struct dm_thin_lookup_result lookup;
1555
1556         if (end < begin)
1557                 return -ENODATA;
1558
1559         r = __find_next_mapped_block(td, begin, &begin, &lookup);
1560         if (r)
1561                 return r;
1562
1563         if (begin >= end)
1564                 return -ENODATA;
1565
1566         *thin_begin = begin;
1567         *pool_begin = lookup.block;
1568         *maybe_shared = lookup.shared;
1569
1570         begin++;
1571         pool_end = *pool_begin + 1;
1572         while (begin != end) {
1573                 r = __find_block(td, begin, true, &lookup);
1574                 if (r) {
1575                         if (r == -ENODATA)
1576                                 break;
1577                         else
1578                                 return r;
1579                 }
1580
1581                 if ((lookup.block != pool_end) ||
1582                     (lookup.shared != *maybe_shared))
1583                         break;
1584
1585                 pool_end++;
1586                 begin++;
1587         }
1588
1589         *thin_end = begin;
1590         return 0;
1591 }
1592
1593 int dm_thin_find_mapped_range(struct dm_thin_device *td,
1594                               dm_block_t begin, dm_block_t end,
1595                               dm_block_t *thin_begin, dm_block_t *thin_end,
1596                               dm_block_t *pool_begin, bool *maybe_shared)
1597 {
1598         int r = -EINVAL;
1599         struct dm_pool_metadata *pmd = td->pmd;
1600
1601         down_read(&pmd->root_lock);
1602         if (!pmd->fail_io) {
1603                 r = __find_mapped_range(td, begin, end, thin_begin, thin_end,
1604                                         pool_begin, maybe_shared);
1605         }
1606         up_read(&pmd->root_lock);
1607
1608         return r;
1609 }
1610
1611 static int __insert(struct dm_thin_device *td, dm_block_t block,
1612                     dm_block_t data_block)
1613 {
1614         int r, inserted;
1615         __le64 value;
1616         struct dm_pool_metadata *pmd = td->pmd;
1617         dm_block_t keys[2] = { td->id, block };
1618
1619         value = cpu_to_le64(pack_block_time(data_block, pmd->time));
1620         __dm_bless_for_disk(&value);
1621
1622         r = dm_btree_insert_notify(&pmd->info, pmd->root, keys, &value,
1623                                    &pmd->root, &inserted);
1624         if (r)
1625                 return r;
1626
1627         td->changed = true;
1628         if (inserted)
1629                 td->mapped_blocks++;
1630
1631         return 0;
1632 }
1633
1634 int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
1635                          dm_block_t data_block)
1636 {
1637         int r = -EINVAL;
1638
1639         pmd_write_lock(td->pmd);
1640         if (!td->pmd->fail_io)
1641                 r = __insert(td, block, data_block);
1642         pmd_write_unlock(td->pmd);
1643
1644         return r;
1645 }
1646
1647 static int __remove(struct dm_thin_device *td, dm_block_t block)
1648 {
1649         int r;
1650         struct dm_pool_metadata *pmd = td->pmd;
1651         dm_block_t keys[2] = { td->id, block };
1652
1653         r = dm_btree_remove(&pmd->info, pmd->root, keys, &pmd->root);
1654         if (r)
1655                 return r;
1656
1657         td->mapped_blocks--;
1658         td->changed = true;
1659
1660         return 0;
1661 }
1662
1663 static int __remove_range(struct dm_thin_device *td, dm_block_t begin, dm_block_t end)
1664 {
1665         int r;
1666         unsigned count, total_count = 0;
1667         struct dm_pool_metadata *pmd = td->pmd;
1668         dm_block_t keys[1] = { td->id };
1669         __le64 value;
1670         dm_block_t mapping_root;
1671
1672         /*
1673          * Find the mapping tree
1674          */
1675         r = dm_btree_lookup(&pmd->tl_info, pmd->root, keys, &value);
1676         if (r)
1677                 return r;
1678
1679         /*
1680          * Remove from the mapping tree, taking care to inc the
1681          * ref count so it doesn't get deleted.
1682          */
1683         mapping_root = le64_to_cpu(value);
1684         dm_tm_inc(pmd->tm, mapping_root);
1685         r = dm_btree_remove(&pmd->tl_info, pmd->root, keys, &pmd->root);
1686         if (r)
1687                 return r;
1688
1689         /*
1690          * Remove leaves stops at the first unmapped entry, so we have to
1691          * loop round finding mapped ranges.
1692          */
1693         while (begin < end) {
1694                 r = dm_btree_lookup_next(&pmd->bl_info, mapping_root, &begin, &begin, &value);
1695                 if (r == -ENODATA)
1696                         break;
1697
1698                 if (r)
1699                         return r;
1700
1701                 if (begin >= end)
1702                         break;
1703
1704                 r = dm_btree_remove_leaves(&pmd->bl_info, mapping_root, &begin, end, &mapping_root, &count);
1705                 if (r)
1706                         return r;
1707
1708                 total_count += count;
1709         }
1710
1711         td->mapped_blocks -= total_count;
1712         td->changed = true;
1713
1714         /*
1715          * Reinsert the mapping tree.
1716          */
1717         value = cpu_to_le64(mapping_root);
1718         __dm_bless_for_disk(&value);
1719         return dm_btree_insert(&pmd->tl_info, pmd->root, keys, &value, &pmd->root);
1720 }
1721
1722 int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block)
1723 {
1724         int r = -EINVAL;
1725
1726         pmd_write_lock(td->pmd);
1727         if (!td->pmd->fail_io)
1728                 r = __remove(td, block);
1729         pmd_write_unlock(td->pmd);
1730
1731         return r;
1732 }
1733
1734 int dm_thin_remove_range(struct dm_thin_device *td,
1735                          dm_block_t begin, dm_block_t end)
1736 {
1737         int r = -EINVAL;
1738
1739         pmd_write_lock(td->pmd);
1740         if (!td->pmd->fail_io)
1741                 r = __remove_range(td, begin, end);
1742         pmd_write_unlock(td->pmd);
1743
1744         return r;
1745 }
1746
1747 int dm_pool_block_is_shared(struct dm_pool_metadata *pmd, dm_block_t b, bool *result)
1748 {
1749         int r;
1750         uint32_t ref_count;
1751
1752         down_read(&pmd->root_lock);
1753         r = dm_sm_get_count(pmd->data_sm, b, &ref_count);
1754         if (!r)
1755                 *result = (ref_count > 1);
1756         up_read(&pmd->root_lock);
1757
1758         return r;
1759 }
1760
1761 int dm_pool_inc_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e)
1762 {
1763         int r = 0;
1764
1765         pmd_write_lock(pmd);
1766         for (; b != e; b++) {
1767                 r = dm_sm_inc_block(pmd->data_sm, b);
1768                 if (r)
1769                         break;
1770         }
1771         pmd_write_unlock(pmd);
1772
1773         return r;
1774 }
1775
1776 int dm_pool_dec_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e)
1777 {
1778         int r = 0;
1779
1780         pmd_write_lock(pmd);
1781         for (; b != e; b++) {
1782                 r = dm_sm_dec_block(pmd->data_sm, b);
1783                 if (r)
1784                         break;
1785         }
1786         pmd_write_unlock(pmd);
1787
1788         return r;
1789 }
1790
1791 bool dm_thin_changed_this_transaction(struct dm_thin_device *td)
1792 {
1793         int r;
1794
1795         down_read(&td->pmd->root_lock);
1796         r = td->changed;
1797         up_read(&td->pmd->root_lock);
1798
1799         return r;
1800 }
1801
1802 bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd)
1803 {
1804         bool r = false;
1805         struct dm_thin_device *td, *tmp;
1806
1807         down_read(&pmd->root_lock);
1808         list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
1809                 if (td->changed) {
1810                         r = td->changed;
1811                         break;
1812                 }
1813         }
1814         up_read(&pmd->root_lock);
1815
1816         return r;
1817 }
1818
1819 bool dm_thin_aborted_changes(struct dm_thin_device *td)
1820 {
1821         bool r;
1822
1823         down_read(&td->pmd->root_lock);
1824         r = td->aborted_with_changes;
1825         up_read(&td->pmd->root_lock);
1826
1827         return r;
1828 }
1829
1830 int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result)
1831 {
1832         int r = -EINVAL;
1833
1834         pmd_write_lock(pmd);
1835         if (!pmd->fail_io)
1836                 r = dm_sm_new_block(pmd->data_sm, result);
1837         pmd_write_unlock(pmd);
1838
1839         return r;
1840 }
1841
1842 int dm_pool_commit_metadata(struct dm_pool_metadata *pmd)
1843 {
1844         int r = -EINVAL;
1845
1846         /*
1847          * Care is taken to not have commit be what
1848          * triggers putting the thin-pool in-service.
1849          */
1850         pmd_write_lock_in_core(pmd);
1851         if (pmd->fail_io)
1852                 goto out;
1853
1854         r = __commit_transaction(pmd);
1855         if (r < 0)
1856                 goto out;
1857
1858         /*
1859          * Open the next transaction.
1860          */
1861         r = __begin_transaction(pmd);
1862 out:
1863         pmd_write_unlock(pmd);
1864         return r;
1865 }
1866
1867 static void __set_abort_with_changes_flags(struct dm_pool_metadata *pmd)
1868 {
1869         struct dm_thin_device *td;
1870
1871         list_for_each_entry(td, &pmd->thin_devices, list)
1872                 td->aborted_with_changes = td->changed;
1873 }
1874
1875 int dm_pool_abort_metadata(struct dm_pool_metadata *pmd)
1876 {
1877         int r = -EINVAL;
1878
1879         pmd_write_lock(pmd);
1880         if (pmd->fail_io)
1881                 goto out;
1882
1883         __set_abort_with_changes_flags(pmd);
1884         __destroy_persistent_data_objects(pmd);
1885         r = __create_persistent_data_objects(pmd, false);
1886         if (r)
1887                 pmd->fail_io = true;
1888
1889 out:
1890         pmd_write_unlock(pmd);
1891
1892         return r;
1893 }
1894
1895 int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, dm_block_t *result)
1896 {
1897         int r = -EINVAL;
1898
1899         down_read(&pmd->root_lock);
1900         if (!pmd->fail_io)
1901                 r = dm_sm_get_nr_free(pmd->data_sm, result);
1902         up_read(&pmd->root_lock);
1903
1904         return r;
1905 }
1906
1907 int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
1908                                           dm_block_t *result)
1909 {
1910         int r = -EINVAL;
1911
1912         down_read(&pmd->root_lock);
1913         if (!pmd->fail_io)
1914                 r = dm_sm_get_nr_free(pmd->metadata_sm, result);
1915
1916         if (!r) {
1917                 if (*result < pmd->metadata_reserve)
1918                         *result = 0;
1919                 else
1920                         *result -= pmd->metadata_reserve;
1921         }
1922         up_read(&pmd->root_lock);
1923
1924         return r;
1925 }
1926
1927 int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
1928                                   dm_block_t *result)
1929 {
1930         int r = -EINVAL;
1931
1932         down_read(&pmd->root_lock);
1933         if (!pmd->fail_io)
1934                 r = dm_sm_get_nr_blocks(pmd->metadata_sm, result);
1935         up_read(&pmd->root_lock);
1936
1937         return r;
1938 }
1939
1940 int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result)
1941 {
1942         int r = -EINVAL;
1943
1944         down_read(&pmd->root_lock);
1945         if (!pmd->fail_io)
1946                 r = dm_sm_get_nr_blocks(pmd->data_sm, result);
1947         up_read(&pmd->root_lock);
1948
1949         return r;
1950 }
1951
1952 int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result)
1953 {
1954         int r = -EINVAL;
1955         struct dm_pool_metadata *pmd = td->pmd;
1956
1957         down_read(&pmd->root_lock);
1958         if (!pmd->fail_io) {
1959                 *result = td->mapped_blocks;
1960                 r = 0;
1961         }
1962         up_read(&pmd->root_lock);
1963
1964         return r;
1965 }
1966
1967 static int __highest_block(struct dm_thin_device *td, dm_block_t *result)
1968 {
1969         int r;
1970         __le64 value_le;
1971         dm_block_t thin_root;
1972         struct dm_pool_metadata *pmd = td->pmd;
1973
1974         r = dm_btree_lookup(&pmd->tl_info, pmd->root, &td->id, &value_le);
1975         if (r)
1976                 return r;
1977
1978         thin_root = le64_to_cpu(value_le);
1979
1980         return dm_btree_find_highest_key(&pmd->bl_info, thin_root, result);
1981 }
1982
1983 int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
1984                                      dm_block_t *result)
1985 {
1986         int r = -EINVAL;
1987         struct dm_pool_metadata *pmd = td->pmd;
1988
1989         down_read(&pmd->root_lock);
1990         if (!pmd->fail_io)
1991                 r = __highest_block(td, result);
1992         up_read(&pmd->root_lock);
1993
1994         return r;
1995 }
1996
1997 static int __resize_space_map(struct dm_space_map *sm, dm_block_t new_count)
1998 {
1999         int r;
2000         dm_block_t old_count;
2001
2002         r = dm_sm_get_nr_blocks(sm, &old_count);
2003         if (r)
2004                 return r;
2005
2006         if (new_count == old_count)
2007                 return 0;
2008
2009         if (new_count < old_count) {
2010                 DMERR("cannot reduce size of space map");
2011                 return -EINVAL;
2012         }
2013
2014         return dm_sm_extend(sm, new_count - old_count);
2015 }
2016
2017 int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
2018 {
2019         int r = -EINVAL;
2020
2021         pmd_write_lock(pmd);
2022         if (!pmd->fail_io)
2023                 r = __resize_space_map(pmd->data_sm, new_count);
2024         pmd_write_unlock(pmd);
2025
2026         return r;
2027 }
2028
2029 int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
2030 {
2031         int r = -EINVAL;
2032
2033         pmd_write_lock(pmd);
2034         if (!pmd->fail_io) {
2035                 r = __resize_space_map(pmd->metadata_sm, new_count);
2036                 if (!r)
2037                         __set_metadata_reserve(pmd);
2038         }
2039         pmd_write_unlock(pmd);
2040
2041         return r;
2042 }
2043
2044 void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd)
2045 {
2046         pmd_write_lock_in_core(pmd);
2047         dm_bm_set_read_only(pmd->bm);
2048         pmd_write_unlock(pmd);
2049 }
2050
2051 void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd)
2052 {
2053         pmd_write_lock_in_core(pmd);
2054         dm_bm_set_read_write(pmd->bm);
2055         pmd_write_unlock(pmd);
2056 }
2057
2058 int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd,
2059                                         dm_block_t threshold,
2060                                         dm_sm_threshold_fn fn,
2061                                         void *context)
2062 {
2063         int r;
2064
2065         pmd_write_lock_in_core(pmd);
2066         r = dm_sm_register_threshold_callback(pmd->metadata_sm, threshold, fn, context);
2067         pmd_write_unlock(pmd);
2068
2069         return r;
2070 }
2071
2072 void dm_pool_register_pre_commit_callback(struct dm_pool_metadata *pmd,
2073                                           dm_pool_pre_commit_fn fn,
2074                                           void *context)
2075 {
2076         pmd_write_lock_in_core(pmd);
2077         pmd->pre_commit_fn = fn;
2078         pmd->pre_commit_context = context;
2079         pmd_write_unlock(pmd);
2080 }
2081
2082 int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd)
2083 {
2084         int r = -EINVAL;
2085         struct dm_block *sblock;
2086         struct thin_disk_superblock *disk_super;
2087
2088         pmd_write_lock(pmd);
2089         if (pmd->fail_io)
2090                 goto out;
2091
2092         pmd->flags |= THIN_METADATA_NEEDS_CHECK_FLAG;
2093
2094         r = superblock_lock(pmd, &sblock);
2095         if (r) {
2096                 DMERR("couldn't lock superblock");
2097                 goto out;
2098         }
2099
2100         disk_super = dm_block_data(sblock);
2101         disk_super->flags = cpu_to_le32(pmd->flags);
2102
2103         dm_bm_unlock(sblock);
2104 out:
2105         pmd_write_unlock(pmd);
2106         return r;
2107 }
2108
2109 bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd)
2110 {
2111         bool needs_check;
2112
2113         down_read(&pmd->root_lock);
2114         needs_check = pmd->flags & THIN_METADATA_NEEDS_CHECK_FLAG;
2115         up_read(&pmd->root_lock);
2116
2117         return needs_check;
2118 }
2119
2120 void dm_pool_issue_prefetches(struct dm_pool_metadata *pmd)
2121 {
2122         down_read(&pmd->root_lock);
2123         if (!pmd->fail_io)
2124                 dm_tm_issue_prefetches(pmd->tm);
2125         up_read(&pmd->root_lock);
2126 }