kernel/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          * We commit to ensure the btree roots which we increment in a
1211          * moment are up to date.
1212          */
1213         __commit_transaction(pmd);
1214
1215         /*
1216          * Copy the superblock.
1217          */
1218         dm_sm_inc_block(pmd->metadata_sm, THIN_SUPERBLOCK_LOCATION);
1219         r = dm_tm_shadow_block(pmd->tm, THIN_SUPERBLOCK_LOCATION,
1220                                &sb_validator, &copy, &inc);
1221         if (r)
1222                 return r;
1223
1224         BUG_ON(!inc);
1225
1226         held_root = dm_block_location(copy);
1227         disk_super = dm_block_data(copy);
1228
1229         if (le64_to_cpu(disk_super->held_root)) {
1230                 DMWARN("Pool metadata snapshot already exists: release this before taking another.");
1231
1232                 dm_tm_dec(pmd->tm, held_root);
1233                 dm_tm_unlock(pmd->tm, copy);
1234                 return -EBUSY;
1235         }
1236
1237         /*
1238          * Wipe the spacemap since we're not publishing this.
1239          */
1240         memset(&disk_super->data_space_map_root, 0,
1241                sizeof(disk_super->data_space_map_root));
1242         memset(&disk_super->metadata_space_map_root, 0,
1243                sizeof(disk_super->metadata_space_map_root));
1244
1245         /*
1246          * Increment the data structures that need to be preserved.
1247          */
1248         dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->data_mapping_root));
1249         dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->device_details_root));
1250         dm_tm_unlock(pmd->tm, copy);
1251
1252         /*
1253          * Write the held root into the superblock.
1254          */
1255         r = superblock_lock(pmd, &sblock);
1256         if (r) {
1257                 dm_tm_dec(pmd->tm, held_root);
1258                 return r;
1259         }
1260
1261         disk_super = dm_block_data(sblock);
1262         disk_super->held_root = cpu_to_le64(held_root);
1263         dm_bm_unlock(sblock);
1264         return 0;
1265 }
1266
1267 int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd)
1268 {
1269         int r = -EINVAL;
1270
1271         down_write(&pmd->root_lock);
1272         if (!pmd->fail_io)
1273                 r = __reserve_metadata_snap(pmd);
1274         up_write(&pmd->root_lock);
1275
1276         return r;
1277 }
1278
1279 static int __release_metadata_snap(struct dm_pool_metadata *pmd)
1280 {
1281         int r;
1282         struct thin_disk_superblock *disk_super;
1283         struct dm_block *sblock, *copy;
1284         dm_block_t held_root;
1285
1286         r = superblock_lock(pmd, &sblock);
1287         if (r)
1288                 return r;
1289
1290         disk_super = dm_block_data(sblock);
1291         held_root = le64_to_cpu(disk_super->held_root);
1292         disk_super->held_root = cpu_to_le64(0);
1293
1294         dm_bm_unlock(sblock);
1295
1296         if (!held_root) {
1297                 DMWARN("No pool metadata snapshot found: nothing to release.");
1298                 return -EINVAL;
1299         }
1300
1301         r = dm_tm_read_lock(pmd->tm, held_root, &sb_validator, &copy);
1302         if (r)
1303                 return r;
1304
1305         disk_super = dm_block_data(copy);
1306         dm_btree_del(&pmd->info, le64_to_cpu(disk_super->data_mapping_root));
1307         dm_btree_del(&pmd->details_info, le64_to_cpu(disk_super->device_details_root));
1308         dm_sm_dec_block(pmd->metadata_sm, held_root);
1309
1310         dm_tm_unlock(pmd->tm, copy);
1311
1312         return 0;
1313 }
1314
1315 int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd)
1316 {
1317         int r = -EINVAL;
1318
1319         down_write(&pmd->root_lock);
1320         if (!pmd->fail_io)
1321                 r = __release_metadata_snap(pmd);
1322         up_write(&pmd->root_lock);
1323
1324         return r;
1325 }
1326
1327 static int __get_metadata_snap(struct dm_pool_metadata *pmd,
1328                                dm_block_t *result)
1329 {
1330         int r;
1331         struct thin_disk_superblock *disk_super;
1332         struct dm_block *sblock;
1333
1334         r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
1335                             &sb_validator, &sblock);
1336         if (r)
1337                 return r;
1338
1339         disk_super = dm_block_data(sblock);
1340         *result = le64_to_cpu(disk_super->held_root);
1341
1342         dm_bm_unlock(sblock);
1343
1344         return 0;
1345 }
1346
1347 int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd,
1348                               dm_block_t *result)
1349 {
1350         int r = -EINVAL;
1351
1352         down_read(&pmd->root_lock);
1353         if (!pmd->fail_io)
1354                 r = __get_metadata_snap(pmd, result);
1355         up_read(&pmd->root_lock);
1356
1357         return r;
1358 }
1359
1360 int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
1361                              struct dm_thin_device **td)
1362 {
1363         int r = -EINVAL;
1364
1365         down_write(&pmd->root_lock);
1366         if (!pmd->fail_io)
1367                 r = __open_device(pmd, dev, 0, td);
1368         up_write(&pmd->root_lock);
1369
1370         return r;
1371 }
1372
1373 int dm_pool_close_thin_device(struct dm_thin_device *td)
1374 {
1375         down_write(&td->pmd->root_lock);
1376         __close_device(td);
1377         up_write(&td->pmd->root_lock);
1378
1379         return 0;
1380 }
1381
1382 dm_thin_id dm_thin_dev_id(struct dm_thin_device *td)
1383 {
1384         return td->id;
1385 }
1386
1387 /*
1388  * Check whether @time (of block creation) is older than @td's last snapshot.
1389  * If so then the associated block is shared with the last snapshot device.
1390  * Any block on a device created *after* the device last got snapshotted is
1391  * necessarily not shared.
1392  */
1393 static bool __snapshotted_since(struct dm_thin_device *td, uint32_t time)
1394 {
1395         return td->snapshotted_time > time;
1396 }
1397
1398 int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
1399                        int can_issue_io, struct dm_thin_lookup_result *result)
1400 {
1401         int r;
1402         __le64 value;
1403         struct dm_pool_metadata *pmd = td->pmd;
1404         dm_block_t keys[2] = { td->id, block };
1405         struct dm_btree_info *info;
1406
1407         down_read(&pmd->root_lock);
1408         if (pmd->fail_io) {
1409                 up_read(&pmd->root_lock);
1410                 return -EINVAL;
1411         }
1412
1413         if (can_issue_io) {
1414                 info = &pmd->info;
1415         } else
1416                 info = &pmd->nb_info;
1417
1418         r = dm_btree_lookup(info, pmd->root, keys, &value);
1419         if (!r) {
1420                 uint64_t block_time = 0;
1421                 dm_block_t exception_block;
1422                 uint32_t exception_time;
1423
1424                 block_time = le64_to_cpu(value);
1425                 unpack_block_time(block_time, &exception_block,
1426                                   &exception_time);
1427                 result->block = exception_block;
1428                 result->shared = __snapshotted_since(td, exception_time);
1429         }
1430
1431         up_read(&pmd->root_lock);
1432         return r;
1433 }
1434
1435 /* FIXME: write a more efficient one in btree */
1436 int dm_thin_find_mapped_range(struct dm_thin_device *td,
1437                               dm_block_t begin, dm_block_t end,
1438                               dm_block_t *thin_begin, dm_block_t *thin_end,
1439                               dm_block_t *pool_begin, bool *maybe_shared)
1440 {
1441         int r;
1442         dm_block_t pool_end;
1443         struct dm_thin_lookup_result lookup;
1444
1445         if (end < begin)
1446                 return -ENODATA;
1447
1448         /*
1449          * Find first mapped block.
1450          */
1451         while (begin < end) {
1452                 r = dm_thin_find_block(td, begin, true, &lookup);
1453                 if (r) {
1454                         if (r != -ENODATA)
1455                                 return r;
1456                 } else
1457                         break;
1458
1459                 begin++;
1460         }
1461
1462         if (begin == end)
1463                 return -ENODATA;
1464
1465         *thin_begin = begin;
1466         *pool_begin = lookup.block;
1467         *maybe_shared = lookup.shared;
1468
1469         begin++;
1470         pool_end = *pool_begin + 1;
1471         while (begin != end) {
1472                 r = dm_thin_find_block(td, begin, true, &lookup);
1473                 if (r) {
1474                         if (r == -ENODATA)
1475                                 break;
1476                         else
1477                                 return r;
1478                 }
1479
1480                 if ((lookup.block != pool_end) ||
1481                     (lookup.shared != *maybe_shared))
1482                         break;
1483
1484                 pool_end++;
1485                 begin++;
1486         }
1487
1488         *thin_end = begin;
1489         return 0;
1490 }
1491
1492 static int __insert(struct dm_thin_device *td, dm_block_t block,
1493                     dm_block_t data_block)
1494 {
1495         int r, inserted;
1496         __le64 value;
1497         struct dm_pool_metadata *pmd = td->pmd;
1498         dm_block_t keys[2] = { td->id, block };
1499
1500         value = cpu_to_le64(pack_block_time(data_block, pmd->time));
1501         __dm_bless_for_disk(&value);
1502
1503         r = dm_btree_insert_notify(&pmd->info, pmd->root, keys, &value,
1504                                    &pmd->root, &inserted);
1505         if (r)
1506                 return r;
1507
1508         td->changed = 1;
1509         if (inserted)
1510                 td->mapped_blocks++;
1511
1512         return 0;
1513 }
1514
1515 int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
1516                          dm_block_t data_block)
1517 {
1518         int r = -EINVAL;
1519
1520         down_write(&td->pmd->root_lock);
1521         if (!td->pmd->fail_io)
1522                 r = __insert(td, block, data_block);
1523         up_write(&td->pmd->root_lock);
1524
1525         return r;
1526 }
1527
1528 static int __remove(struct dm_thin_device *td, dm_block_t block)
1529 {
1530         int r;
1531         struct dm_pool_metadata *pmd = td->pmd;
1532         dm_block_t keys[2] = { td->id, block };
1533
1534         r = dm_btree_remove(&pmd->info, pmd->root, keys, &pmd->root);
1535         if (r)
1536                 return r;
1537
1538         td->mapped_blocks--;
1539         td->changed = 1;
1540
1541         return 0;
1542 }
1543
1544 static int __remove_range(struct dm_thin_device *td, dm_block_t begin, dm_block_t end)
1545 {
1546         int r;
1547         unsigned count, total_count = 0;
1548         struct dm_pool_metadata *pmd = td->pmd;
1549         dm_block_t keys[1] = { td->id };
1550         __le64 value;
1551         dm_block_t mapping_root;
1552
1553         /*
1554          * Find the mapping tree
1555          */
1556         r = dm_btree_lookup(&pmd->tl_info, pmd->root, keys, &value);
1557         if (r)
1558                 return r;
1559
1560         /*
1561          * Remove from the mapping tree, taking care to inc the
1562          * ref count so it doesn't get deleted.
1563          */
1564         mapping_root = le64_to_cpu(value);
1565         dm_tm_inc(pmd->tm, mapping_root);
1566         r = dm_btree_remove(&pmd->tl_info, pmd->root, keys, &pmd->root);
1567         if (r)
1568                 return r;
1569
1570         /*
1571          * Remove leaves stops at the first unmapped entry, so we have to
1572          * loop round finding mapped ranges.
1573          */
1574         while (begin < end) {
1575                 r = dm_btree_lookup_next(&pmd->bl_info, mapping_root, &begin, &begin, &value);
1576                 if (r == -ENODATA)
1577                         break;
1578
1579                 if (r)
1580                         return r;
1581
1582                 if (begin >= end)
1583                         break;
1584
1585                 r = dm_btree_remove_leaves(&pmd->bl_info, mapping_root, &begin, end, &mapping_root, &count);
1586                 if (r)
1587                         return r;
1588
1589                 total_count += count;
1590         }
1591
1592         td->mapped_blocks -= total_count;
1593         td->changed = 1;
1594
1595         /*
1596          * Reinsert the mapping tree.
1597          */
1598         value = cpu_to_le64(mapping_root);
1599         __dm_bless_for_disk(&value);
1600         return dm_btree_insert(&pmd->tl_info, pmd->root, keys, &value, &pmd->root);
1601 }
1602
1603 int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block)
1604 {
1605         int r = -EINVAL;
1606
1607         down_write(&td->pmd->root_lock);
1608         if (!td->pmd->fail_io)
1609                 r = __remove(td, block);
1610         up_write(&td->pmd->root_lock);
1611
1612         return r;
1613 }
1614
1615 int dm_thin_remove_range(struct dm_thin_device *td,
1616                          dm_block_t begin, dm_block_t end)
1617 {
1618         int r = -EINVAL;
1619
1620         down_write(&td->pmd->root_lock);
1621         if (!td->pmd->fail_io)
1622                 r = __remove_range(td, begin, end);
1623         up_write(&td->pmd->root_lock);
1624
1625         return r;
1626 }
1627
1628 int dm_pool_block_is_used(struct dm_pool_metadata *pmd, dm_block_t b, bool *result)
1629 {
1630         int r;
1631         uint32_t ref_count;
1632
1633         down_read(&pmd->root_lock);
1634         r = dm_sm_get_count(pmd->data_sm, b, &ref_count);
1635         if (!r)
1636                 *result = (ref_count != 0);
1637         up_read(&pmd->root_lock);
1638
1639         return r;
1640 }
1641
1642 bool dm_thin_changed_this_transaction(struct dm_thin_device *td)
1643 {
1644         int r;
1645
1646         down_read(&td->pmd->root_lock);
1647         r = td->changed;
1648         up_read(&td->pmd->root_lock);
1649
1650         return r;
1651 }
1652
1653 bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd)
1654 {
1655         bool r = false;
1656         struct dm_thin_device *td, *tmp;
1657
1658         down_read(&pmd->root_lock);
1659         list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
1660                 if (td->changed) {
1661                         r = td->changed;
1662                         break;
1663                 }
1664         }
1665         up_read(&pmd->root_lock);
1666
1667         return r;
1668 }
1669
1670 bool dm_thin_aborted_changes(struct dm_thin_device *td)
1671 {
1672         bool r;
1673
1674         down_read(&td->pmd->root_lock);
1675         r = td->aborted_with_changes;
1676         up_read(&td->pmd->root_lock);
1677
1678         return r;
1679 }
1680
1681 int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result)
1682 {
1683         int r = -EINVAL;
1684
1685         down_write(&pmd->root_lock);
1686         if (!pmd->fail_io)
1687                 r = dm_sm_new_block(pmd->data_sm, result);
1688         up_write(&pmd->root_lock);
1689
1690         return r;
1691 }
1692
1693 int dm_pool_commit_metadata(struct dm_pool_metadata *pmd)
1694 {
1695         int r = -EINVAL;
1696
1697         down_write(&pmd->root_lock);
1698         if (pmd->fail_io)
1699                 goto out;
1700
1701         r = __commit_transaction(pmd);
1702         if (r <= 0)
1703                 goto out;
1704
1705         /*
1706          * Open the next transaction.
1707          */
1708         r = __begin_transaction(pmd);
1709 out:
1710         up_write(&pmd->root_lock);
1711         return r;
1712 }
1713
1714 static void __set_abort_with_changes_flags(struct dm_pool_metadata *pmd)
1715 {
1716         struct dm_thin_device *td;
1717
1718         list_for_each_entry(td, &pmd->thin_devices, list)
1719                 td->aborted_with_changes = td->changed;
1720 }
1721
1722 int dm_pool_abort_metadata(struct dm_pool_metadata *pmd)
1723 {
1724         int r = -EINVAL;
1725
1726         down_write(&pmd->root_lock);
1727         if (pmd->fail_io)
1728                 goto out;
1729
1730         __set_abort_with_changes_flags(pmd);
1731         __destroy_persistent_data_objects(pmd);
1732         r = __create_persistent_data_objects(pmd, false);
1733         if (r)
1734                 pmd->fail_io = true;
1735
1736 out:
1737         up_write(&pmd->root_lock);
1738
1739         return r;
1740 }
1741
1742 int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, dm_block_t *result)
1743 {
1744         int r = -EINVAL;
1745
1746         down_read(&pmd->root_lock);
1747         if (!pmd->fail_io)
1748                 r = dm_sm_get_nr_free(pmd->data_sm, result);
1749         up_read(&pmd->root_lock);
1750
1751         return r;
1752 }
1753
1754 int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
1755                                           dm_block_t *result)
1756 {
1757         int r = -EINVAL;
1758
1759         down_read(&pmd->root_lock);
1760         if (!pmd->fail_io)
1761                 r = dm_sm_get_nr_free(pmd->metadata_sm, result);
1762         up_read(&pmd->root_lock);
1763
1764         return r;
1765 }
1766
1767 int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
1768                                   dm_block_t *result)
1769 {
1770         int r = -EINVAL;
1771
1772         down_read(&pmd->root_lock);
1773         if (!pmd->fail_io)
1774                 r = dm_sm_get_nr_blocks(pmd->metadata_sm, result);
1775         up_read(&pmd->root_lock);
1776
1777         return r;
1778 }
1779
1780 int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result)
1781 {
1782         int r = -EINVAL;
1783
1784         down_read(&pmd->root_lock);
1785         if (!pmd->fail_io)
1786                 r = dm_sm_get_nr_blocks(pmd->data_sm, result);
1787         up_read(&pmd->root_lock);
1788
1789         return r;
1790 }
1791
1792 int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result)
1793 {
1794         int r = -EINVAL;
1795         struct dm_pool_metadata *pmd = td->pmd;
1796
1797         down_read(&pmd->root_lock);
1798         if (!pmd->fail_io) {
1799                 *result = td->mapped_blocks;
1800                 r = 0;
1801         }
1802         up_read(&pmd->root_lock);
1803
1804         return r;
1805 }
1806
1807 static int __highest_block(struct dm_thin_device *td, dm_block_t *result)
1808 {
1809         int r;
1810         __le64 value_le;
1811         dm_block_t thin_root;
1812         struct dm_pool_metadata *pmd = td->pmd;
1813
1814         r = dm_btree_lookup(&pmd->tl_info, pmd->root, &td->id, &value_le);
1815         if (r)
1816                 return r;
1817
1818         thin_root = le64_to_cpu(value_le);
1819
1820         return dm_btree_find_highest_key(&pmd->bl_info, thin_root, result);
1821 }
1822
1823 int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
1824                                      dm_block_t *result)
1825 {
1826         int r = -EINVAL;
1827         struct dm_pool_metadata *pmd = td->pmd;
1828
1829         down_read(&pmd->root_lock);
1830         if (!pmd->fail_io)
1831                 r = __highest_block(td, result);
1832         up_read(&pmd->root_lock);
1833
1834         return r;
1835 }
1836
1837 static int __resize_space_map(struct dm_space_map *sm, dm_block_t new_count)
1838 {
1839         int r;
1840         dm_block_t old_count;
1841
1842         r = dm_sm_get_nr_blocks(sm, &old_count);
1843         if (r)
1844                 return r;
1845
1846         if (new_count == old_count)
1847                 return 0;
1848
1849         if (new_count < old_count) {
1850                 DMERR("cannot reduce size of space map");
1851                 return -EINVAL;
1852         }
1853
1854         return dm_sm_extend(sm, new_count - old_count);
1855 }
1856
1857 int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
1858 {
1859         int r = -EINVAL;
1860
1861         down_write(&pmd->root_lock);
1862         if (!pmd->fail_io)
1863                 r = __resize_space_map(pmd->data_sm, new_count);
1864         up_write(&pmd->root_lock);
1865
1866         return r;
1867 }
1868
1869 int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
1870 {
1871         int r = -EINVAL;
1872
1873         down_write(&pmd->root_lock);
1874         if (!pmd->fail_io)
1875                 r = __resize_space_map(pmd->metadata_sm, new_count);
1876         up_write(&pmd->root_lock);
1877
1878         return r;
1879 }
1880
1881 void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd)
1882 {
1883         down_write(&pmd->root_lock);
1884         dm_bm_set_read_only(pmd->bm);
1885         up_write(&pmd->root_lock);
1886 }
1887
1888 void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd)
1889 {
1890         down_write(&pmd->root_lock);
1891         dm_bm_set_read_write(pmd->bm);
1892         up_write(&pmd->root_lock);
1893 }
1894
1895 int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd,
1896                                         dm_block_t threshold,
1897                                         dm_sm_threshold_fn fn,
1898                                         void *context)
1899 {
1900         int r;
1901
1902         down_write(&pmd->root_lock);
1903         r = dm_sm_register_threshold_callback(pmd->metadata_sm, threshold, fn, context);
1904         up_write(&pmd->root_lock);
1905
1906         return r;
1907 }
1908
1909 int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd)
1910 {
1911         int r;
1912         struct dm_block *sblock;
1913         struct thin_disk_superblock *disk_super;
1914
1915         down_write(&pmd->root_lock);
1916         pmd->flags |= THIN_METADATA_NEEDS_CHECK_FLAG;
1917
1918         r = superblock_lock(pmd, &sblock);
1919         if (r) {
1920                 DMERR("couldn't read superblock");
1921                 goto out;
1922         }
1923
1924         disk_super = dm_block_data(sblock);
1925         disk_super->flags = cpu_to_le32(pmd->flags);
1926
1927         dm_bm_unlock(sblock);
1928 out:
1929         up_write(&pmd->root_lock);
1930         return r;
1931 }
1932
1933 bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd)
1934 {
1935         bool needs_check;
1936
1937         down_read(&pmd->root_lock);
1938         needs_check = pmd->flags & THIN_METADATA_NEEDS_CHECK_FLAG;
1939         up_read(&pmd->root_lock);
1940
1941         return needs_check;
1942 }
1943
1944 void dm_pool_issue_prefetches(struct dm_pool_metadata *pmd)
1945 {
1946         dm_tm_issue_prefetches(pmd->tm);
1947 }