drivers/md/persistent-data/dm-array.c

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This source file includes following definitions.
array_block_prepare_for_write
array_block_check
element_at
on_entries
inc_ablock_entries
dec_ablock_entries
calc_max_entries
alloc_ablock
fill_ablock
trim_ablock
get_ablock
unlock_ablock
lookup_ablock
insert_ablock
__shadow_ablock
__reinsert_ablock
shadow_ablock
insert_new_ablock
insert_full_ablocks
drop_blocks
total_nr_blocks_needed
shrink
grow_extend_tail_block
grow_add_tail_block
grow_needs_more_blocks
grow
block_inc
block_dec
block_equal
dm_array_info_init
dm_array_empty
array_resize
dm_array_resize
populate_ablock_with_values
dm_array_new
dm_array_del
dm_array_get_value
array_set_value
dm_array_set_value
walk_ablock
dm_array_walk
load_ablock
dm_array_cursor_begin
dm_array_cursor_end
dm_array_cursor_next
dm_array_cursor_skip
dm_array_cursor_get_value
   1 /*
   2  * Copyright (C) 2012 Red Hat, Inc.
   3  *
   4  * This file is released under the GPL.
   5  */
   6 
   7 #include "dm-array.h"
   8 #include "dm-space-map.h"
   9 #include "dm-transaction-manager.h"
  10 
  11 #include <linux/export.h>
  12 #include <linux/device-mapper.h>
  13 
  14 #define DM_MSG_PREFIX "array"
  15 
  16 /*----------------------------------------------------------------*/
  17 
  18 /*
  19  * The array is implemented as a fully populated btree, which points to
  20  * blocks that contain the packed values.  This is more space efficient
  21  * than just using a btree since we don't store 1 key per value.
  22  */
  23 struct array_block {
  24         __le32 csum;
  25         __le32 max_entries;
  26         __le32 nr_entries;
  27         __le32 value_size;
  28         __le64 blocknr; /* Block this node is supposed to live in. */
  29 } __packed;
  30 
  31 /*----------------------------------------------------------------*/
  32 
  33 /*
  34  * Validator methods.  As usual we calculate a checksum, and also write the
  35  * block location into the header (paranoia about ssds remapping areas by
  36  * mistake).
  37  */
  38 #define CSUM_XOR 595846735
  39 
  40 static void array_block_prepare_for_write(struct dm_block_validator *v,
  41                                           struct dm_block *b,
  42                                           size_t size_of_block)
  43 {
  44         struct array_block *bh_le = dm_block_data(b);
  45 
  46         bh_le->blocknr = cpu_to_le64(dm_block_location(b));
  47         bh_le->csum = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
  48                                                  size_of_block - sizeof(__le32),
  49                                                  CSUM_XOR));
  50 }
  51 
  52 static int array_block_check(struct dm_block_validator *v,
  53                              struct dm_block *b,
  54                              size_t size_of_block)
  55 {
  56         struct array_block *bh_le = dm_block_data(b);
  57         __le32 csum_disk;
  58 
  59         if (dm_block_location(b) != le64_to_cpu(bh_le->blocknr)) {
  60                 DMERR_LIMIT("array_block_check failed: blocknr %llu != wanted %llu",
  61                             (unsigned long long) le64_to_cpu(bh_le->blocknr),
  62                             (unsigned long long) dm_block_location(b));
  63                 return -ENOTBLK;
  64         }
  65 
  66         csum_disk = cpu_to_le32(dm_bm_checksum(&bh_le->max_entries,
  67                                                size_of_block - sizeof(__le32),
  68                                                CSUM_XOR));
  69         if (csum_disk != bh_le->csum) {
  70                 DMERR_LIMIT("array_block_check failed: csum %u != wanted %u",
  71                             (unsigned) le32_to_cpu(csum_disk),
  72                             (unsigned) le32_to_cpu(bh_le->csum));
  73                 return -EILSEQ;
  74         }
  75 
  76         return 0;
  77 }
  78 
  79 static struct dm_block_validator array_validator = {
  80         .name = "array",
  81         .prepare_for_write = array_block_prepare_for_write,
  82         .check = array_block_check
  83 };
  84 
  85 /*----------------------------------------------------------------*/
  86 
  87 /*
  88  * Functions for manipulating the array blocks.
  89  */
  90 
  91 /*
  92  * Returns a pointer to a value within an array block.
  93  *
  94  * index - The index into _this_ specific block.
  95  */
  96 static void *element_at(struct dm_array_info *info, struct array_block *ab,
  97                         unsigned index)
  98 {
  99         unsigned char *entry = (unsigned char *) (ab + 1);
 100 
 101         entry += index * info->value_type.size;
 102 
 103         return entry;
 104 }
 105 
 106 /*
 107  * Utility function that calls one of the value_type methods on every value
 108  * in an array block.
 109  */
 110 static void on_entries(struct dm_array_info *info, struct array_block *ab,
 111                        void (*fn)(void *, const void *))
 112 {
 113         unsigned i, nr_entries = le32_to_cpu(ab->nr_entries);
 114 
 115         for (i = 0; i < nr_entries; i++)
 116                 fn(info->value_type.context, element_at(info, ab, i));
 117 }
 118 
 119 /*
 120  * Increment every value in an array block.
 121  */
 122 static void inc_ablock_entries(struct dm_array_info *info, struct array_block *ab)
 123 {
 124         struct dm_btree_value_type *vt = &info->value_type;
 125 
 126         if (vt->inc)
 127                 on_entries(info, ab, vt->inc);
 128 }
 129 
 130 /*
 131  * Decrement every value in an array block.
 132  */
 133 static void dec_ablock_entries(struct dm_array_info *info, struct array_block *ab)
 134 {
 135         struct dm_btree_value_type *vt = &info->value_type;
 136 
 137         if (vt->dec)
 138                 on_entries(info, ab, vt->dec);
 139 }
 140 
 141 /*
 142  * Each array block can hold this many values.
 143  */
 144 static uint32_t calc_max_entries(size_t value_size, size_t size_of_block)
 145 {
 146         return (size_of_block - sizeof(struct array_block)) / value_size;
 147 }
 148 
 149 /*
 150  * Allocate a new array block.  The caller will need to unlock block.
 151  */
 152 static int alloc_ablock(struct dm_array_info *info, size_t size_of_block,
 153                         uint32_t max_entries,
 154                         struct dm_block **block, struct array_block **ab)
 155 {
 156         int r;
 157 
 158         r = dm_tm_new_block(info->btree_info.tm, &array_validator, block);
 159         if (r)
 160                 return r;
 161 
 162         (*ab) = dm_block_data(*block);
 163         (*ab)->max_entries = cpu_to_le32(max_entries);
 164         (*ab)->nr_entries = cpu_to_le32(0);
 165         (*ab)->value_size = cpu_to_le32(info->value_type.size);
 166 
 167         return 0;
 168 }
 169 
 170 /*
 171  * Pad an array block out with a particular value.  Every instance will
 172  * cause an increment of the value_type.  new_nr must always be more than
 173  * the current number of entries.
 174  */
 175 static void fill_ablock(struct dm_array_info *info, struct array_block *ab,
 176                         const void *value, unsigned new_nr)
 177 {
 178         unsigned i;
 179         uint32_t nr_entries;
 180         struct dm_btree_value_type *vt = &info->value_type;
 181 
 182         BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
 183         BUG_ON(new_nr < le32_to_cpu(ab->nr_entries));
 184 
 185         nr_entries = le32_to_cpu(ab->nr_entries);
 186         for (i = nr_entries; i < new_nr; i++) {
 187                 if (vt->inc)
 188                         vt->inc(vt->context, value);
 189                 memcpy(element_at(info, ab, i), value, vt->size);
 190         }
 191         ab->nr_entries = cpu_to_le32(new_nr);
 192 }
 193 
 194 /*
 195  * Remove some entries from the back of an array block.  Every value
 196  * removed will be decremented.  new_nr must be <= the current number of
 197  * entries.
 198  */
 199 static void trim_ablock(struct dm_array_info *info, struct array_block *ab,
 200                         unsigned new_nr)
 201 {
 202         unsigned i;
 203         uint32_t nr_entries;
 204         struct dm_btree_value_type *vt = &info->value_type;
 205 
 206         BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
 207         BUG_ON(new_nr > le32_to_cpu(ab->nr_entries));
 208 
 209         nr_entries = le32_to_cpu(ab->nr_entries);
 210         for (i = nr_entries; i > new_nr; i--)
 211                 if (vt->dec)
 212                         vt->dec(vt->context, element_at(info, ab, i - 1));
 213         ab->nr_entries = cpu_to_le32(new_nr);
 214 }
 215 
 216 /*
 217  * Read locks a block, and coerces it to an array block.  The caller must
 218  * unlock 'block' when finished.
 219  */
 220 static int get_ablock(struct dm_array_info *info, dm_block_t b,
 221                       struct dm_block **block, struct array_block **ab)
 222 {
 223         int r;
 224 
 225         r = dm_tm_read_lock(info->btree_info.tm, b, &array_validator, block);
 226         if (r)
 227                 return r;
 228 
 229         *ab = dm_block_data(*block);
 230         return 0;
 231 }
 232 
 233 /*
 234  * Unlocks an array block.
 235  */
 236 static void unlock_ablock(struct dm_array_info *info, struct dm_block *block)
 237 {
 238         dm_tm_unlock(info->btree_info.tm, block);
 239 }
 240 
 241 /*----------------------------------------------------------------*/
 242 
 243 /*
 244  * Btree manipulation.
 245  */
 246 
 247 /*
 248  * Looks up an array block in the btree, and then read locks it.
 249  *
 250  * index is the index of the index of the array_block, (ie. the array index
 251  * / max_entries).
 252  */
 253 static int lookup_ablock(struct dm_array_info *info, dm_block_t root,
 254                          unsigned index, struct dm_block **block,
 255                          struct array_block **ab)
 256 {
 257         int r;
 258         uint64_t key = index;
 259         __le64 block_le;
 260 
 261         r = dm_btree_lookup(&info->btree_info, root, &key, &block_le);
 262         if (r)
 263                 return r;
 264 
 265         return get_ablock(info, le64_to_cpu(block_le), block, ab);
 266 }
 267 
 268 /*
 269  * Insert an array block into the btree.  The block is _not_ unlocked.
 270  */
 271 static int insert_ablock(struct dm_array_info *info, uint64_t index,
 272                          struct dm_block *block, dm_block_t *root)
 273 {
 274         __le64 block_le = cpu_to_le64(dm_block_location(block));
 275 
 276         __dm_bless_for_disk(block_le);
 277         return dm_btree_insert(&info->btree_info, *root, &index, &block_le, root);
 278 }
 279 
 280 /*----------------------------------------------------------------*/
 281 
 282 static int __shadow_ablock(struct dm_array_info *info, dm_block_t b,
 283                            struct dm_block **block, struct array_block **ab)
 284 {
 285         int inc;
 286         int r = dm_tm_shadow_block(info->btree_info.tm, b,
 287                                    &array_validator, block, &inc);
 288         if (r)
 289                 return r;
 290 
 291         *ab = dm_block_data(*block);
 292         if (inc)
 293                 inc_ablock_entries(info, *ab);
 294 
 295         return 0;
 296 }
 297 
 298 /*
 299  * The shadow op will often be a noop.  Only insert if it really
 300  * copied data.
 301  */
 302 static int __reinsert_ablock(struct dm_array_info *info, unsigned index,
 303                              struct dm_block *block, dm_block_t b,
 304                              dm_block_t *root)
 305 {
 306         int r = 0;
 307 
 308         if (dm_block_location(block) != b) {
 309                 /*
 310                  * dm_tm_shadow_block will have already decremented the old
 311                  * block, but it is still referenced by the btree.  We
 312                  * increment to stop the insert decrementing it below zero
 313                  * when overwriting the old value.
 314                  */
 315                 dm_tm_inc(info->btree_info.tm, b);
 316                 r = insert_ablock(info, index, block, root);
 317         }
 318 
 319         return r;
 320 }
 321 
 322 /*
 323  * Looks up an array block in the btree.  Then shadows it, and updates the
 324  * btree to point to this new shadow.  'root' is an input/output parameter
 325  * for both the current root block, and the new one.
 326  */
 327 static int shadow_ablock(struct dm_array_info *info, dm_block_t *root,
 328                          unsigned index, struct dm_block **block,
 329                          struct array_block **ab)
 330 {
 331         int r;
 332         uint64_t key = index;
 333         dm_block_t b;
 334         __le64 block_le;
 335 
 336         r = dm_btree_lookup(&info->btree_info, *root, &key, &block_le);
 337         if (r)
 338                 return r;
 339         b = le64_to_cpu(block_le);
 340 
 341         r = __shadow_ablock(info, b, block, ab);
 342         if (r)
 343                 return r;
 344 
 345         return __reinsert_ablock(info, index, *block, b, root);
 346 }
 347 
 348 /*
 349  * Allocate an new array block, and fill it with some values.
 350  */
 351 static int insert_new_ablock(struct dm_array_info *info, size_t size_of_block,
 352                              uint32_t max_entries,
 353                              unsigned block_index, uint32_t nr,
 354                              const void *value, dm_block_t *root)
 355 {
 356         int r;
 357         struct dm_block *block;
 358         struct array_block *ab;
 359 
 360         r = alloc_ablock(info, size_of_block, max_entries, &block, &ab);
 361         if (r)
 362                 return r;
 363 
 364         fill_ablock(info, ab, value, nr);
 365         r = insert_ablock(info, block_index, block, root);
 366         unlock_ablock(info, block);
 367 
 368         return r;
 369 }
 370 
 371 static int insert_full_ablocks(struct dm_array_info *info, size_t size_of_block,
 372                                unsigned begin_block, unsigned end_block,
 373                                unsigned max_entries, const void *value,
 374                                dm_block_t *root)
 375 {
 376         int r = 0;
 377 
 378         for (; !r && begin_block != end_block; begin_block++)
 379                 r = insert_new_ablock(info, size_of_block, max_entries, begin_block, max_entries, value, root);
 380 
 381         return r;
 382 }
 383 
 384 /*
 385  * There are a bunch of functions involved with resizing an array.  This
 386  * structure holds information that commonly needed by them.  Purely here
 387  * to reduce parameter count.
 388  */
 389 struct resize {
 390         /*
 391          * Describes the array.
 392          */
 393         struct dm_array_info *info;
 394 
 395         /*
 396          * The current root of the array.  This gets updated.
 397          */
 398         dm_block_t root;
 399 
 400         /*
 401          * Metadata block size.  Used to calculate the nr entries in an
 402          * array block.
 403          */
 404         size_t size_of_block;
 405 
 406         /*
 407          * Maximum nr entries in an array block.
 408          */
 409         unsigned max_entries;
 410 
 411         /*
 412          * nr of completely full blocks in the array.
 413          *
 414          * 'old' refers to before the resize, 'new' after.
 415          */
 416         unsigned old_nr_full_blocks, new_nr_full_blocks;
 417 
 418         /*
 419          * Number of entries in the final block.  0 iff only full blocks in
 420          * the array.
 421          */
 422         unsigned old_nr_entries_in_last_block, new_nr_entries_in_last_block;
 423 
 424         /*
 425          * The default value used when growing the array.
 426          */
 427         const void *value;
 428 };
 429 
 430 /*
 431  * Removes a consecutive set of array blocks from the btree.  The values
 432  * in block are decremented as a side effect of the btree remove.
 433  *
 434  * begin_index - the index of the first array block to remove.
 435  * end_index - the one-past-the-end value.  ie. this block is not removed.
 436  */
 437 static int drop_blocks(struct resize *resize, unsigned begin_index,
 438                        unsigned end_index)
 439 {
 440         int r;
 441 
 442         while (begin_index != end_index) {
 443                 uint64_t key = begin_index++;
 444                 r = dm_btree_remove(&resize->info->btree_info, resize->root,
 445                                     &key, &resize->root);
 446                 if (r)
 447                         return r;
 448         }
 449 
 450         return 0;
 451 }
 452 
 453 /*
 454  * Calculates how many blocks are needed for the array.
 455  */
 456 static unsigned total_nr_blocks_needed(unsigned nr_full_blocks,
 457                                        unsigned nr_entries_in_last_block)
 458 {
 459         return nr_full_blocks + (nr_entries_in_last_block ? 1 : 0);
 460 }
 461 
 462 /*
 463  * Shrink an array.
 464  */
 465 static int shrink(struct resize *resize)
 466 {
 467         int r;
 468         unsigned begin, end;
 469         struct dm_block *block;
 470         struct array_block *ab;
 471 
 472         /*
 473          * Lose some blocks from the back?
 474          */
 475         if (resize->new_nr_full_blocks < resize->old_nr_full_blocks) {
 476                 begin = total_nr_blocks_needed(resize->new_nr_full_blocks,
 477                                                resize->new_nr_entries_in_last_block);
 478                 end = total_nr_blocks_needed(resize->old_nr_full_blocks,
 479                                              resize->old_nr_entries_in_last_block);
 480 
 481                 r = drop_blocks(resize, begin, end);
 482                 if (r)
 483                         return r;
 484         }
 485 
 486         /*
 487          * Trim the new tail block
 488          */
 489         if (resize->new_nr_entries_in_last_block) {
 490                 r = shadow_ablock(resize->info, &resize->root,
 491                                   resize->new_nr_full_blocks, &block, &ab);
 492                 if (r)
 493                         return r;
 494 
 495                 trim_ablock(resize->info, ab, resize->new_nr_entries_in_last_block);
 496                 unlock_ablock(resize->info, block);
 497         }
 498 
 499         return 0;
 500 }
 501 
 502 /*
 503  * Grow an array.
 504  */
 505 static int grow_extend_tail_block(struct resize *resize, uint32_t new_nr_entries)
 506 {
 507         int r;
 508         struct dm_block *block;
 509         struct array_block *ab;
 510 
 511         r = shadow_ablock(resize->info, &resize->root,
 512                           resize->old_nr_full_blocks, &block, &ab);
 513         if (r)
 514                 return r;
 515 
 516         fill_ablock(resize->info, ab, resize->value, new_nr_entries);
 517         unlock_ablock(resize->info, block);
 518 
 519         return r;
 520 }
 521 
 522 static int grow_add_tail_block(struct resize *resize)
 523 {
 524         return insert_new_ablock(resize->info, resize->size_of_block,
 525                                  resize->max_entries,
 526                                  resize->new_nr_full_blocks,
 527                                  resize->new_nr_entries_in_last_block,
 528                                  resize->value, &resize->root);
 529 }
 530 
 531 static int grow_needs_more_blocks(struct resize *resize)
 532 {
 533         int r;
 534         unsigned old_nr_blocks = resize->old_nr_full_blocks;
 535 
 536         if (resize->old_nr_entries_in_last_block > 0) {
 537                 old_nr_blocks++;
 538 
 539                 r = grow_extend_tail_block(resize, resize->max_entries);
 540                 if (r)
 541                         return r;
 542         }
 543 
 544         r = insert_full_ablocks(resize->info, resize->size_of_block,
 545                                 old_nr_blocks,
 546                                 resize->new_nr_full_blocks,
 547                                 resize->max_entries, resize->value,
 548                                 &resize->root);
 549         if (r)
 550                 return r;
 551 
 552         if (resize->new_nr_entries_in_last_block)
 553                 r = grow_add_tail_block(resize);
 554 
 555         return r;
 556 }
 557 
 558 static int grow(struct resize *resize)
 559 {
 560         if (resize->new_nr_full_blocks > resize->old_nr_full_blocks)
 561                 return grow_needs_more_blocks(resize);
 562 
 563         else if (resize->old_nr_entries_in_last_block)
 564                 return grow_extend_tail_block(resize, resize->new_nr_entries_in_last_block);
 565 
 566         else
 567                 return grow_add_tail_block(resize);
 568 }
 569 
 570 /*----------------------------------------------------------------*/
 571 
 572 /*
 573  * These are the value_type functions for the btree elements, which point
 574  * to array blocks.
 575  */
 576 static void block_inc(void *context, const void *value)
 577 {
 578         __le64 block_le;
 579         struct dm_array_info *info = context;
 580 
 581         memcpy(&block_le, value, sizeof(block_le));
 582         dm_tm_inc(info->btree_info.tm, le64_to_cpu(block_le));
 583 }
 584 
 585 static void block_dec(void *context, const void *value)
 586 {
 587         int r;
 588         uint64_t b;
 589         __le64 block_le;
 590         uint32_t ref_count;
 591         struct dm_block *block;
 592         struct array_block *ab;
 593         struct dm_array_info *info = context;
 594 
 595         memcpy(&block_le, value, sizeof(block_le));
 596         b = le64_to_cpu(block_le);
 597 
 598         r = dm_tm_ref(info->btree_info.tm, b, &ref_count);
 599         if (r) {
 600                 DMERR_LIMIT("couldn't get reference count for block %llu",
 601                             (unsigned long long) b);
 602                 return;
 603         }
 604 
 605         if (ref_count == 1) {
 606                 /*
 607                  * We're about to drop the last reference to this ablock.
 608                  * So we need to decrement the ref count of the contents.
 609                  */
 610                 r = get_ablock(info, b, &block, &ab);
 611                 if (r) {
 612                         DMERR_LIMIT("couldn't get array block %llu",
 613                                     (unsigned long long) b);
 614                         return;
 615                 }
 616 
 617                 dec_ablock_entries(info, ab);
 618                 unlock_ablock(info, block);
 619         }
 620 
 621         dm_tm_dec(info->btree_info.tm, b);
 622 }
 623 
 624 static int block_equal(void *context, const void *value1, const void *value2)
 625 {
 626         return !memcmp(value1, value2, sizeof(__le64));
 627 }
 628 
 629 /*----------------------------------------------------------------*/
 630 
 631 void dm_array_info_init(struct dm_array_info *info,
 632                         struct dm_transaction_manager *tm,
 633                         struct dm_btree_value_type *vt)
 634 {
 635         struct dm_btree_value_type *bvt = &info->btree_info.value_type;
 636 
 637         memcpy(&info->value_type, vt, sizeof(info->value_type));
 638         info->btree_info.tm = tm;
 639         info->btree_info.levels = 1;
 640 
 641         bvt->context = info;
 642         bvt->size = sizeof(__le64);
 643         bvt->inc = block_inc;
 644         bvt->dec = block_dec;
 645         bvt->equal = block_equal;
 646 }
 647 EXPORT_SYMBOL_GPL(dm_array_info_init);
 648 
 649 int dm_array_empty(struct dm_array_info *info, dm_block_t *root)
 650 {
 651         return dm_btree_empty(&info->btree_info, root);
 652 }
 653 EXPORT_SYMBOL_GPL(dm_array_empty);
 654 
 655 static int array_resize(struct dm_array_info *info, dm_block_t root,
 656                         uint32_t old_size, uint32_t new_size,
 657                         const void *value, dm_block_t *new_root)
 658 {
 659         int r;
 660         struct resize resize;
 661 
 662         if (old_size == new_size) {
 663                 *new_root = root;
 664                 return 0;
 665         }
 666 
 667         resize.info = info;
 668         resize.root = root;
 669         resize.size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
 670         resize.max_entries = calc_max_entries(info->value_type.size,
 671                                               resize.size_of_block);
 672 
 673         resize.old_nr_full_blocks = old_size / resize.max_entries;
 674         resize.old_nr_entries_in_last_block = old_size % resize.max_entries;
 675         resize.new_nr_full_blocks = new_size / resize.max_entries;
 676         resize.new_nr_entries_in_last_block = new_size % resize.max_entries;
 677         resize.value = value;
 678 
 679         r = ((new_size > old_size) ? grow : shrink)(&resize);
 680         if (r)
 681                 return r;
 682 
 683         *new_root = resize.root;
 684         return 0;
 685 }
 686 
 687 int dm_array_resize(struct dm_array_info *info, dm_block_t root,
 688                     uint32_t old_size, uint32_t new_size,
 689                     const void *value, dm_block_t *new_root)
 690                     __dm_written_to_disk(value)
 691 {
 692         int r = array_resize(info, root, old_size, new_size, value, new_root);
 693         __dm_unbless_for_disk(value);
 694         return r;
 695 }
 696 EXPORT_SYMBOL_GPL(dm_array_resize);
 697 
 698 static int populate_ablock_with_values(struct dm_array_info *info, struct array_block *ab,
 699                                        value_fn fn, void *context, unsigned base, unsigned new_nr)
 700 {
 701         int r;
 702         unsigned i;
 703         struct dm_btree_value_type *vt = &info->value_type;
 704 
 705         BUG_ON(le32_to_cpu(ab->nr_entries));
 706         BUG_ON(new_nr > le32_to_cpu(ab->max_entries));
 707 
 708         for (i = 0; i < new_nr; i++) {
 709                 r = fn(base + i, element_at(info, ab, i), context);
 710                 if (r)
 711                         return r;
 712 
 713                 if (vt->inc)
 714                         vt->inc(vt->context, element_at(info, ab, i));
 715         }
 716 
 717         ab->nr_entries = cpu_to_le32(new_nr);
 718         return 0;
 719 }
 720 
 721 int dm_array_new(struct dm_array_info *info, dm_block_t *root,
 722                  uint32_t size, value_fn fn, void *context)
 723 {
 724         int r;
 725         struct dm_block *block;
 726         struct array_block *ab;
 727         unsigned block_index, end_block, size_of_block, max_entries;
 728 
 729         r = dm_array_empty(info, root);
 730         if (r)
 731                 return r;
 732 
 733         size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
 734         max_entries = calc_max_entries(info->value_type.size, size_of_block);
 735         end_block = dm_div_up(size, max_entries);
 736 
 737         for (block_index = 0; block_index != end_block; block_index++) {
 738                 r = alloc_ablock(info, size_of_block, max_entries, &block, &ab);
 739                 if (r)
 740                         break;
 741 
 742                 r = populate_ablock_with_values(info, ab, fn, context,
 743                                                 block_index * max_entries,
 744                                                 min(max_entries, size));
 745                 if (r) {
 746                         unlock_ablock(info, block);
 747                         break;
 748                 }
 749 
 750                 r = insert_ablock(info, block_index, block, root);
 751                 unlock_ablock(info, block);
 752                 if (r)
 753                         break;
 754 
 755                 size -= max_entries;
 756         }
 757 
 758         return r;
 759 }
 760 EXPORT_SYMBOL_GPL(dm_array_new);
 761 
 762 int dm_array_del(struct dm_array_info *info, dm_block_t root)
 763 {
 764         return dm_btree_del(&info->btree_info, root);
 765 }
 766 EXPORT_SYMBOL_GPL(dm_array_del);
 767 
 768 int dm_array_get_value(struct dm_array_info *info, dm_block_t root,
 769                        uint32_t index, void *value_le)
 770 {
 771         int r;
 772         struct dm_block *block;
 773         struct array_block *ab;
 774         size_t size_of_block;
 775         unsigned entry, max_entries;
 776 
 777         size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
 778         max_entries = calc_max_entries(info->value_type.size, size_of_block);
 779 
 780         r = lookup_ablock(info, root, index / max_entries, &block, &ab);
 781         if (r)
 782                 return r;
 783 
 784         entry = index % max_entries;
 785         if (entry >= le32_to_cpu(ab->nr_entries))
 786                 r = -ENODATA;
 787         else
 788                 memcpy(value_le, element_at(info, ab, entry),
 789                        info->value_type.size);
 790 
 791         unlock_ablock(info, block);
 792         return r;
 793 }
 794 EXPORT_SYMBOL_GPL(dm_array_get_value);
 795 
 796 static int array_set_value(struct dm_array_info *info, dm_block_t root,
 797                            uint32_t index, const void *value, dm_block_t *new_root)
 798 {
 799         int r;
 800         struct dm_block *block;
 801         struct array_block *ab;
 802         size_t size_of_block;
 803         unsigned max_entries;
 804         unsigned entry;
 805         void *old_value;
 806         struct dm_btree_value_type *vt = &info->value_type;
 807 
 808         size_of_block = dm_bm_block_size(dm_tm_get_bm(info->btree_info.tm));
 809         max_entries = calc_max_entries(info->value_type.size, size_of_block);
 810 
 811         r = shadow_ablock(info, &root, index / max_entries, &block, &ab);
 812         if (r)
 813                 return r;
 814         *new_root = root;
 815 
 816         entry = index % max_entries;
 817         if (entry >= le32_to_cpu(ab->nr_entries)) {
 818                 r = -ENODATA;
 819                 goto out;
 820         }
 821 
 822         old_value = element_at(info, ab, entry);
 823         if (vt->dec &&
 824             (!vt->equal || !vt->equal(vt->context, old_value, value))) {
 825                 vt->dec(vt->context, old_value);
 826                 if (vt->inc)
 827                         vt->inc(vt->context, value);
 828         }
 829 
 830         memcpy(old_value, value, info->value_type.size);
 831 
 832 out:
 833         unlock_ablock(info, block);
 834         return r;
 835 }
 836 
 837 int dm_array_set_value(struct dm_array_info *info, dm_block_t root,
 838                  uint32_t index, const void *value, dm_block_t *new_root)
 839                  __dm_written_to_disk(value)
 840 {
 841         int r;
 842 
 843         r = array_set_value(info, root, index, value, new_root);
 844         __dm_unbless_for_disk(value);
 845         return r;
 846 }
 847 EXPORT_SYMBOL_GPL(dm_array_set_value);
 848 
 849 struct walk_info {
 850         struct dm_array_info *info;
 851         int (*fn)(void *context, uint64_t key, void *leaf);
 852         void *context;
 853 };
 854 
 855 static int walk_ablock(void *context, uint64_t *keys, void *leaf)
 856 {
 857         struct walk_info *wi = context;
 858 
 859         int r;
 860         unsigned i;
 861         __le64 block_le;
 862         unsigned nr_entries, max_entries;
 863         struct dm_block *block;
 864         struct array_block *ab;
 865 
 866         memcpy(&block_le, leaf, sizeof(block_le));
 867         r = get_ablock(wi->info, le64_to_cpu(block_le), &block, &ab);
 868         if (r)
 869                 return r;
 870 
 871         max_entries = le32_to_cpu(ab->max_entries);
 872         nr_entries = le32_to_cpu(ab->nr_entries);
 873         for (i = 0; i < nr_entries; i++) {
 874                 r = wi->fn(wi->context, keys[0] * max_entries + i,
 875                            element_at(wi->info, ab, i));
 876 
 877                 if (r)
 878                         break;
 879         }
 880 
 881         unlock_ablock(wi->info, block);
 882         return r;
 883 }
 884 
 885 int dm_array_walk(struct dm_array_info *info, dm_block_t root,
 886                   int (*fn)(void *, uint64_t key, void *leaf),
 887                   void *context)
 888 {
 889         struct walk_info wi;
 890 
 891         wi.info = info;
 892         wi.fn = fn;
 893         wi.context = context;
 894 
 895         return dm_btree_walk(&info->btree_info, root, walk_ablock, &wi);
 896 }
 897 EXPORT_SYMBOL_GPL(dm_array_walk);
 898 
 899 /*----------------------------------------------------------------*/
 900 
 901 static int load_ablock(struct dm_array_cursor *c)
 902 {
 903         int r;
 904         __le64 value_le;
 905         uint64_t key;
 906 
 907         if (c->block)
 908                 unlock_ablock(c->info, c->block);
 909 
 910         c->block = NULL;
 911         c->ab = NULL;
 912         c->index = 0;
 913 
 914         r = dm_btree_cursor_get_value(&c->cursor, &key, &value_le);
 915         if (r) {
 916                 DMERR("dm_btree_cursor_get_value failed");
 917                 dm_btree_cursor_end(&c->cursor);
 918 
 919         } else {
 920                 r = get_ablock(c->info, le64_to_cpu(value_le), &c->block, &c->ab);
 921                 if (r) {
 922                         DMERR("get_ablock failed");
 923                         dm_btree_cursor_end(&c->cursor);
 924                 }
 925         }
 926 
 927         return r;
 928 }
 929 
 930 int dm_array_cursor_begin(struct dm_array_info *info, dm_block_t root,
 931                           struct dm_array_cursor *c)
 932 {
 933         int r;
 934 
 935         memset(c, 0, sizeof(*c));
 936         c->info = info;
 937         r = dm_btree_cursor_begin(&info->btree_info, root, true, &c->cursor);
 938         if (r) {
 939                 DMERR("couldn't create btree cursor");
 940                 return r;
 941         }
 942 
 943         return load_ablock(c);
 944 }
 945 EXPORT_SYMBOL_GPL(dm_array_cursor_begin);
 946 
 947 void dm_array_cursor_end(struct dm_array_cursor *c)
 948 {
 949         if (c->block) {
 950                 unlock_ablock(c->info, c->block);
 951                 dm_btree_cursor_end(&c->cursor);
 952         }
 953 }
 954 EXPORT_SYMBOL_GPL(dm_array_cursor_end);
 955 
 956 int dm_array_cursor_next(struct dm_array_cursor *c)
 957 {
 958         int r;
 959 
 960         if (!c->block)
 961                 return -ENODATA;
 962 
 963         c->index++;
 964 
 965         if (c->index >= le32_to_cpu(c->ab->nr_entries)) {
 966                 r = dm_btree_cursor_next(&c->cursor);
 967                 if (r)
 968                         return r;
 969 
 970                 r = load_ablock(c);
 971                 if (r)
 972                         return r;
 973         }
 974 
 975         return 0;
 976 }
 977 EXPORT_SYMBOL_GPL(dm_array_cursor_next);
 978 
 979 int dm_array_cursor_skip(struct dm_array_cursor *c, uint32_t count)
 980 {
 981         int r;
 982 
 983         do {
 984                 uint32_t remaining = le32_to_cpu(c->ab->nr_entries) - c->index;
 985 
 986                 if (count < remaining) {
 987                         c->index += count;
 988                         return 0;
 989                 }
 990 
 991                 count -= remaining;
 992                 r = dm_array_cursor_next(c);
 993 
 994         } while (!r);
 995 
 996         return r;
 997 }
 998 EXPORT_SYMBOL_GPL(dm_array_cursor_skip);
 999 
1000 void dm_array_cursor_get_value(struct dm_array_cursor *c, void **value_le)
1001 {
1002         *value_le = element_at(c->info, c->ab, c->index);
1003 }
1004 EXPORT_SYMBOL_GPL(dm_array_cursor_get_value);
1005 
1006 /*----------------------------------------------------------------*/
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root/drivers/md/persistent-data/dm-array.c

DEFINITIONS
