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