drivers/md/dm-thin-metadata.c

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