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

   1 /*
   2  * Copyright (C) 2011 Red Hat, Inc.
   3  *
   4  * This file is released under the GPL.
   5  */
   6
   7 #include "dm-btree-internal.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 "btree"
  15
  16 /*----------------------------------------------------------------
  17  * Array manipulation
  18  *--------------------------------------------------------------*/
  19 static void memcpy_disk(void *dest, const void *src, size_t len)
  20         __dm_written_to_disk(src)
  21 {
  22         memcpy(dest, src, len);
  23         __dm_unbless_for_disk(src);
  24 }
  25
  26 static void array_insert(void *base, size_t elt_size, unsigned nr_elts,
  27                          unsigned index, void *elt)
  28         __dm_written_to_disk(elt)
  29 {
  30         if (index < nr_elts)
  31                 memmove(base + (elt_size * (index + 1)),
  32                         base + (elt_size * index),
  33                         (nr_elts - index) * elt_size);
  34
  35         memcpy_disk(base + (elt_size * index), elt, elt_size);
  36 }
  37
  38 /*----------------------------------------------------------------*/
  39
  40 /* makes the assumption that no two keys are the same. */
  41 static int bsearch(struct btree_node *n, uint64_t key, int want_hi)
  42 {
  43         int lo = -1, hi = le32_to_cpu(n->header.nr_entries);
  44
  45         while (hi - lo > 1) {
  46                 int mid = lo + ((hi - lo) / 2);
  47                 uint64_t mid_key = le64_to_cpu(n->keys[mid]);
  48
  49                 if (mid_key == key)
  50                         return mid;
  51
  52                 if (mid_key < key)
  53                         lo = mid;
  54                 else
  55                         hi = mid;
  56         }
  57
  58         return want_hi ? hi : lo;
  59 }
  60
  61 int lower_bound(struct btree_node *n, uint64_t key)
  62 {
  63         return bsearch(n, key, 0);
  64 }
  65
  66 void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
  67                   struct dm_btree_value_type *vt)
  68 {
  69         unsigned i;
  70         uint32_t nr_entries = le32_to_cpu(n->header.nr_entries);
  71
  72         if (le32_to_cpu(n->header.flags) & INTERNAL_NODE)
  73                 for (i = 0; i < nr_entries; i++)
  74                         dm_tm_inc(tm, value64(n, i));
  75         else if (vt->inc)
  76                 for (i = 0; i < nr_entries; i++)
  77                         vt->inc(vt->context, value_ptr(n, i));
  78 }
  79
  80 static int insert_at(size_t value_size, struct btree_node *node, unsigned index,
  81                       uint64_t key, void *value)
  82                       __dm_written_to_disk(value)
  83 {
  84         uint32_t nr_entries = le32_to_cpu(node->header.nr_entries);
  85         __le64 key_le = cpu_to_le64(key);
  86
  87         if (index > nr_entries ||
  88             index >= le32_to_cpu(node->header.max_entries)) {
  89                 DMERR("too many entries in btree node for insert");
  90                 __dm_unbless_for_disk(value);
  91                 return -ENOMEM;
  92         }
  93
  94         __dm_bless_for_disk(&key_le);
  95
  96         array_insert(node->keys, sizeof(*node->keys), nr_entries, index, &key_le);
  97         array_insert(value_base(node), value_size, nr_entries, index, value);
  98         node->header.nr_entries = cpu_to_le32(nr_entries + 1);
  99
 100         return 0;
 101 }
 102
 103 /*----------------------------------------------------------------*/
 104
 105 /*
 106  * We want 3n entries (for some n).  This works more nicely for repeated
 107  * insert remove loops than (2n + 1).
 108  */
 109 static uint32_t calc_max_entries(size_t value_size, size_t block_size)
 110 {
 111         uint32_t total, n;
 112         size_t elt_size = sizeof(uint64_t) + value_size; /* key + value */
 113
 114         block_size -= sizeof(struct node_header);
 115         total = block_size / elt_size;
 116         n = total / 3;          /* rounds down */
 117
 118         return 3 * n;
 119 }
 120
 121 int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root)
 122 {
 123         int r;
 124         struct dm_block *b;
 125         struct btree_node *n;
 126         size_t block_size;
 127         uint32_t max_entries;
 128
 129         r = new_block(info, &b);
 130         if (r < 0)
 131                 return r;
 132
 133         block_size = dm_bm_block_size(dm_tm_get_bm(info->tm));
 134         max_entries = calc_max_entries(info->value_type.size, block_size);
 135
 136         n = dm_block_data(b);
 137         memset(n, 0, block_size);
 138         n->header.flags = cpu_to_le32(LEAF_NODE);
 139         n->header.nr_entries = cpu_to_le32(0);
 140         n->header.max_entries = cpu_to_le32(max_entries);
 141         n->header.value_size = cpu_to_le32(info->value_type.size);
 142
 143         *root = dm_block_location(b);
 144         return unlock_block(info, b);
 145 }
 146 EXPORT_SYMBOL_GPL(dm_btree_empty);
 147
 148 /*----------------------------------------------------------------*/
 149
 150 /*
 151  * Deletion uses a recursive algorithm, since we have limited stack space
 152  * we explicitly manage our own stack on the heap.
 153  */
 154 #define MAX_SPINE_DEPTH 64
 155 struct frame {
 156         struct dm_block *b;
 157         struct btree_node *n;
 158         unsigned level;
 159         unsigned nr_children;
 160         unsigned current_child;
 161 };
 162
 163 struct del_stack {
 164         struct dm_transaction_manager *tm;
 165         int top;
 166         struct frame spine[MAX_SPINE_DEPTH];
 167 };
 168
 169 static int top_frame(struct del_stack *s, struct frame **f)
 170 {
 171         if (s->top < 0) {
 172                 DMERR("btree deletion stack empty");
 173                 return -EINVAL;
 174         }
 175
 176         *f = s->spine + s->top;
 177
 178         return 0;
 179 }
 180
 181 static int unprocessed_frames(struct del_stack *s)
 182 {
 183         return s->top >= 0;
 184 }
 185
 186 static int push_frame(struct del_stack *s, dm_block_t b, unsigned level)
 187 {
 188         int r;
 189         uint32_t ref_count;
 190
 191         if (s->top >= MAX_SPINE_DEPTH - 1) {
 192                 DMERR("btree deletion stack out of memory");
 193                 return -ENOMEM;
 194         }
 195
 196         r = dm_tm_ref(s->tm, b, &ref_count);
 197         if (r)
 198                 return r;
 199
 200         if (ref_count > 1)
 201                 /*
 202                  * This is a shared node, so we can just decrement it's
 203                  * reference counter and leave the children.
 204                  */
 205                 dm_tm_dec(s->tm, b);
 206
 207         else {
 208                 struct frame *f = s->spine + ++s->top;
 209
 210                 r = dm_tm_read_lock(s->tm, b, &btree_node_validator, &f->b);
 211                 if (r) {
 212                         s->top--;
 213                         return r;
 214                 }
 215
 216                 f->n = dm_block_data(f->b);
 217                 f->level = level;
 218                 f->nr_children = le32_to_cpu(f->n->header.nr_entries);
 219                 f->current_child = 0;
 220         }
 221
 222         return 0;
 223 }
 224
 225 static void pop_frame(struct del_stack *s)
 226 {
 227         struct frame *f = s->spine + s->top--;
 228
 229         dm_tm_dec(s->tm, dm_block_location(f->b));
 230         dm_tm_unlock(s->tm, f->b);
 231 }
 232
 233 int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
 234 {
 235         int r;
 236         struct del_stack *s;
 237
 238         s = kmalloc(sizeof(*s), GFP_KERNEL);
 239         if (!s)
 240                 return -ENOMEM;
 241         s->tm = info->tm;
 242         s->top = -1;
 243
 244         r = push_frame(s, root, 1);
 245         if (r)
 246                 goto out;
 247
 248         while (unprocessed_frames(s)) {
 249                 uint32_t flags;
 250                 struct frame *f;
 251                 dm_block_t b;
 252
 253                 r = top_frame(s, &f);
 254                 if (r)
 255                         goto out;
 256
 257                 if (f->current_child >= f->nr_children) {
 258                         pop_frame(s);
 259                         continue;
 260                 }
 261
 262                 flags = le32_to_cpu(f->n->header.flags);
 263                 if (flags & INTERNAL_NODE) {
 264                         b = value64(f->n, f->current_child);
 265                         f->current_child++;
 266                         r = push_frame(s, b, f->level);
 267                         if (r)
 268                                 goto out;
 269
 270                 } else if (f->level != (info->levels - 1)) {
 271                         b = value64(f->n, f->current_child);
 272                         f->current_child++;
 273                         r = push_frame(s, b, f->level + 1);
 274                         if (r)
 275                                 goto out;
 276
 277                 } else {
 278                         if (info->value_type.dec) {
 279                                 unsigned i;
 280
 281                                 for (i = 0; i < f->nr_children; i++)
 282                                         info->value_type.dec(info->value_type.context,
 283                                                              value_ptr(f->n, i));
 284                         }
 285                         f->current_child = f->nr_children;
 286                 }
 287         }
 288
 289 out:
 290         kfree(s);
 291         return r;
 292 }
 293 EXPORT_SYMBOL_GPL(dm_btree_del);
 294
 295 /*----------------------------------------------------------------*/
 296
 297 static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key,
 298                             int (*search_fn)(struct btree_node *, uint64_t),
 299                             uint64_t *result_key, void *v, size_t value_size)
 300 {
 301         int i, r;
 302         uint32_t flags, nr_entries;
 303
 304         do {
 305                 r = ro_step(s, block);
 306                 if (r < 0)
 307                         return r;
 308
 309                 i = search_fn(ro_node(s), key);
 310
 311                 flags = le32_to_cpu(ro_node(s)->header.flags);
 312                 nr_entries = le32_to_cpu(ro_node(s)->header.nr_entries);
 313                 if (i < 0 || i >= nr_entries)
 314                         return -ENODATA;
 315
 316                 if (flags & INTERNAL_NODE)
 317                         block = value64(ro_node(s), i);
 318
 319         } while (!(flags & LEAF_NODE));
 320
 321         *result_key = le64_to_cpu(ro_node(s)->keys[i]);
 322         memcpy(v, value_ptr(ro_node(s), i), value_size);
 323
 324         return 0;
 325 }
 326
 327 int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,
 328                     uint64_t *keys, void *value_le)
 329 {
 330         unsigned level, last_level = info->levels - 1;
 331         int r = -ENODATA;
 332         uint64_t rkey;
 333         __le64 internal_value_le;
 334         struct ro_spine spine;
 335
 336         init_ro_spine(&spine, info);
 337         for (level = 0; level < info->levels; level++) {
 338                 size_t size;
 339                 void *value_p;
 340
 341                 if (level == last_level) {
 342                         value_p = value_le;
 343                         size = info->value_type.size;
 344
 345                 } else {
 346                         value_p = &internal_value_le;
 347                         size = sizeof(uint64_t);
 348                 }
 349
 350                 r = btree_lookup_raw(&spine, root, keys[level],
 351                                      lower_bound, &rkey,
 352                                      value_p, size);
 353
 354                 if (!r) {
 355                         if (rkey != keys[level]) {
 356                                 exit_ro_spine(&spine);
 357                                 return -ENODATA;
 358                         }
 359                 } else {
 360                         exit_ro_spine(&spine);
 361                         return r;
 362                 }
 363
 364                 root = le64_to_cpu(internal_value_le);
 365         }
 366         exit_ro_spine(&spine);
 367
 368         return r;
 369 }
 370 EXPORT_SYMBOL_GPL(dm_btree_lookup);
 371
 372 /*
 373  * Splits a node by creating a sibling node and shifting half the nodes
 374  * contents across.  Assumes there is a parent node, and it has room for
 375  * another child.
 376  *
 377  * Before:
 378  *        +--------+
 379  *        | Parent |
 380  *        +--------+
 381  *           |
 382  *           v
 383  *      +----------+
 384  *      | A ++++++ |
 385  *      +----------+
 386  *
 387  *
 388  * After:
 389  *              +--------+
 390  *              | Parent |
 391  *              +--------+
 392  *                |     |
 393  *                v     +------+
 394  *          +---------+        |
 395  *          | A* +++  |        v
 396  *          +---------+   +-------+
 397  *                        | B +++ |
 398  *                        +-------+
 399  *
 400  * Where A* is a shadow of A.
 401  */
 402 static int btree_split_sibling(struct shadow_spine *s, dm_block_t root,
 403                                unsigned parent_index, uint64_t key)
 404 {
 405         int r;
 406         size_t size;
 407         unsigned nr_left, nr_right;
 408         struct dm_block *left, *right, *parent;
 409         struct btree_node *ln, *rn, *pn;
 410         __le64 location;
 411
 412         left = shadow_current(s);
 413
 414         r = new_block(s->info, &right);
 415         if (r < 0)
 416                 return r;
 417
 418         ln = dm_block_data(left);
 419         rn = dm_block_data(right);
 420
 421         nr_left = le32_to_cpu(ln->header.nr_entries) / 2;
 422         nr_right = le32_to_cpu(ln->header.nr_entries) - nr_left;
 423
 424         ln->header.nr_entries = cpu_to_le32(nr_left);
 425
 426         rn->header.flags = ln->header.flags;
 427         rn->header.nr_entries = cpu_to_le32(nr_right);
 428         rn->header.max_entries = ln->header.max_entries;
 429         rn->header.value_size = ln->header.value_size;
 430         memcpy(rn->keys, ln->keys + nr_left, nr_right * sizeof(rn->keys[0]));
 431
 432         size = le32_to_cpu(ln->header.flags) & INTERNAL_NODE ?
 433                 sizeof(uint64_t) : s->info->value_type.size;
 434         memcpy(value_ptr(rn, 0), value_ptr(ln, nr_left),
 435                size * nr_right);
 436
 437         /*
 438          * Patch up the parent
 439          */
 440         parent = shadow_parent(s);
 441
 442         pn = dm_block_data(parent);
 443         location = cpu_to_le64(dm_block_location(left));
 444         __dm_bless_for_disk(&location);
 445         memcpy_disk(value_ptr(pn, parent_index),
 446                     &location, sizeof(__le64));
 447
 448         location = cpu_to_le64(dm_block_location(right));
 449         __dm_bless_for_disk(&location);
 450
 451         r = insert_at(sizeof(__le64), pn, parent_index + 1,
 452                       le64_to_cpu(rn->keys[0]), &location);
 453         if (r)
 454                 return r;
 455
 456         if (key < le64_to_cpu(rn->keys[0])) {
 457                 unlock_block(s->info, right);
 458                 s->nodes[1] = left;
 459         } else {
 460                 unlock_block(s->info, left);
 461                 s->nodes[1] = right;
 462         }
 463
 464         return 0;
 465 }
 466
 467 /*
 468  * Splits a node by creating two new children beneath the given node.
 469  *
 470  * Before:
 471  *        +----------+
 472  *        | A ++++++ |
 473  *        +----------+
 474  *
 475  *
 476  * After:
 477  *      +------------+
 478  *      | A (shadow) |
 479  *      +------------+
 480  *          |   |
 481  *   +------+   +----+
 482  *   |               |
 483  *   v               v
 484  * +-------+     +-------+
 485  * | B +++ |     | C +++ |
 486  * +-------+     +-------+
 487  */
 488 static int btree_split_beneath(struct shadow_spine *s, uint64_t key)
 489 {
 490         int r;
 491         size_t size;
 492         unsigned nr_left, nr_right;
 493         struct dm_block *left, *right, *new_parent;
 494         struct btree_node *pn, *ln, *rn;
 495         __le64 val;
 496
 497         new_parent = shadow_current(s);
 498
 499         r = new_block(s->info, &left);
 500         if (r < 0)
 501                 return r;
 502
 503         r = new_block(s->info, &right);
 504         if (r < 0) {
 505                 /* FIXME: put left */
 506                 return r;
 507         }
 508
 509         pn = dm_block_data(new_parent);
 510         ln = dm_block_data(left);
 511         rn = dm_block_data(right);
 512
 513         nr_left = le32_to_cpu(pn->header.nr_entries) / 2;
 514         nr_right = le32_to_cpu(pn->header.nr_entries) - nr_left;
 515
 516         ln->header.flags = pn->header.flags;
 517         ln->header.nr_entries = cpu_to_le32(nr_left);
 518         ln->header.max_entries = pn->header.max_entries;
 519         ln->header.value_size = pn->header.value_size;
 520
 521         rn->header.flags = pn->header.flags;
 522         rn->header.nr_entries = cpu_to_le32(nr_right);
 523         rn->header.max_entries = pn->header.max_entries;
 524         rn->header.value_size = pn->header.value_size;
 525
 526         memcpy(ln->keys, pn->keys, nr_left * sizeof(pn->keys[0]));
 527         memcpy(rn->keys, pn->keys + nr_left, nr_right * sizeof(pn->keys[0]));
 528
 529         size = le32_to_cpu(pn->header.flags) & INTERNAL_NODE ?
 530                 sizeof(__le64) : s->info->value_type.size;
 531         memcpy(value_ptr(ln, 0), value_ptr(pn, 0), nr_left * size);
 532         memcpy(value_ptr(rn, 0), value_ptr(pn, nr_left),
 533                nr_right * size);
 534
 535         /* new_parent should just point to l and r now */
 536         pn->header.flags = cpu_to_le32(INTERNAL_NODE);
 537         pn->header.nr_entries = cpu_to_le32(2);
 538         pn->header.max_entries = cpu_to_le32(
 539                 calc_max_entries(sizeof(__le64),
 540                                  dm_bm_block_size(
 541                                          dm_tm_get_bm(s->info->tm))));
 542         pn->header.value_size = cpu_to_le32(sizeof(__le64));
 543
 544         val = cpu_to_le64(dm_block_location(left));
 545         __dm_bless_for_disk(&val);
 546         pn->keys[0] = ln->keys[0];
 547         memcpy_disk(value_ptr(pn, 0), &val, sizeof(__le64));
 548
 549         val = cpu_to_le64(dm_block_location(right));
 550         __dm_bless_for_disk(&val);
 551         pn->keys[1] = rn->keys[0];
 552         memcpy_disk(value_ptr(pn, 1), &val, sizeof(__le64));
 553
 554         /*
 555          * rejig the spine.  This is ugly, since it knows too
 556          * much about the spine
 557          */
 558         if (s->nodes[0] != new_parent) {
 559                 unlock_block(s->info, s->nodes[0]);
 560                 s->nodes[0] = new_parent;
 561         }
 562         if (key < le64_to_cpu(rn->keys[0])) {
 563                 unlock_block(s->info, right);
 564                 s->nodes[1] = left;
 565         } else {
 566                 unlock_block(s->info, left);
 567                 s->nodes[1] = right;
 568         }
 569         s->count = 2;
 570
 571         return 0;
 572 }
 573
 574 static int btree_insert_raw(struct shadow_spine *s, dm_block_t root,
 575                             struct dm_btree_value_type *vt,
 576                             uint64_t key, unsigned *index)
 577 {
 578         int r, i = *index, top = 1;
 579         struct btree_node *node;
 580
 581         for (;;) {
 582                 r = shadow_step(s, root, vt);
 583                 if (r < 0)
 584                         return r;
 585
 586                 node = dm_block_data(shadow_current(s));
 587
 588                 /*
 589                  * We have to patch up the parent node, ugly, but I don't
 590                  * see a way to do this automatically as part of the spine
 591                  * op.
 592                  */
 593                 if (shadow_has_parent(s) && i >= 0) { /* FIXME: second clause unness. */
 594                         __le64 location = cpu_to_le64(dm_block_location(shadow_current(s)));
 595
 596                         __dm_bless_for_disk(&location);
 597                         memcpy_disk(value_ptr(dm_block_data(shadow_parent(s)), i),
 598                                     &location, sizeof(__le64));
 599                 }
 600
 601                 node = dm_block_data(shadow_current(s));
 602
 603                 if (node->header.nr_entries == node->header.max_entries) {
 604                         if (top)
 605                                 r = btree_split_beneath(s, key);
 606                         else
 607                                 r = btree_split_sibling(s, root, i, key);
 608
 609                         if (r < 0)
 610                                 return r;
 611                 }
 612
 613                 node = dm_block_data(shadow_current(s));
 614
 615                 i = lower_bound(node, key);
 616
 617                 if (le32_to_cpu(node->header.flags) & LEAF_NODE)
 618                         break;
 619
 620                 if (i < 0) {
 621                         /* change the bounds on the lowest key */
 622                         node->keys[0] = cpu_to_le64(key);
 623                         i = 0;
 624                 }
 625
 626                 root = value64(node, i);
 627                 top = 0;
 628         }
 629
 630         if (i < 0 || le64_to_cpu(node->keys[i]) != key)
 631                 i++;
 632
 633         *index = i;
 634         return 0;
 635 }
 636
 637 static int insert(struct dm_btree_info *info, dm_block_t root,
 638                   uint64_t *keys, void *value, dm_block_t *new_root,
 639                   int *inserted)
 640                   __dm_written_to_disk(value)
 641 {
 642         int r, need_insert;
 643         unsigned level, index = -1, last_level = info->levels - 1;
 644         dm_block_t block = root;
 645         struct shadow_spine spine;
 646         struct btree_node *n;
 647         struct dm_btree_value_type le64_type;
 648
 649         le64_type.context = NULL;
 650         le64_type.size = sizeof(__le64);
 651         le64_type.inc = NULL;
 652         le64_type.dec = NULL;
 653         le64_type.equal = NULL;
 654
 655         init_shadow_spine(&spine, info);
 656
 657         for (level = 0; level < (info->levels - 1); level++) {
 658                 r = btree_insert_raw(&spine, block, &le64_type, keys[level], &index);
 659                 if (r < 0)
 660                         goto bad;
 661
 662                 n = dm_block_data(shadow_current(&spine));
 663                 need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) ||
 664                                (le64_to_cpu(n->keys[index]) != keys[level]));
 665
 666                 if (need_insert) {
 667                         dm_block_t new_tree;
 668                         __le64 new_le;
 669
 670                         r = dm_btree_empty(info, &new_tree);
 671                         if (r < 0)
 672                                 goto bad;
 673
 674                         new_le = cpu_to_le64(new_tree);
 675                         __dm_bless_for_disk(&new_le);
 676
 677                         r = insert_at(sizeof(uint64_t), n, index,
 678                                       keys[level], &new_le);
 679                         if (r)
 680                                 goto bad;
 681                 }
 682
 683                 if (level < last_level)
 684                         block = value64(n, index);
 685         }
 686
 687         r = btree_insert_raw(&spine, block, &info->value_type,
 688                              keys[level], &index);
 689         if (r < 0)
 690                 goto bad;
 691
 692         n = dm_block_data(shadow_current(&spine));
 693         need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) ||
 694                        (le64_to_cpu(n->keys[index]) != keys[level]));
 695
 696         if (need_insert) {
 697                 if (inserted)
 698                         *inserted = 1;
 699
 700                 r = insert_at(info->value_type.size, n, index,
 701                               keys[level], value);
 702                 if (r)
 703                         goto bad_unblessed;
 704         } else {
 705                 if (inserted)
 706                         *inserted = 0;
 707
 708                 if (info->value_type.dec &&
 709                     (!info->value_type.equal ||
 710                      !info->value_type.equal(
 711                              info->value_type.context,
 712                              value_ptr(n, index),
 713                              value))) {
 714                         info->value_type.dec(info->value_type.context,
 715                                              value_ptr(n, index));
 716                 }
 717                 memcpy_disk(value_ptr(n, index),
 718                             value, info->value_type.size);
 719         }
 720
 721         *new_root = shadow_root(&spine);
 722         exit_shadow_spine(&spine);
 723
 724         return 0;
 725
 726 bad:
 727         __dm_unbless_for_disk(value);
 728 bad_unblessed:
 729         exit_shadow_spine(&spine);
 730         return r;
 731 }
 732
 733 int dm_btree_insert(struct dm_btree_info *info, dm_block_t root,
 734                     uint64_t *keys, void *value, dm_block_t *new_root)
 735                     __dm_written_to_disk(value)
 736 {
 737         return insert(info, root, keys, value, new_root, NULL);
 738 }
 739 EXPORT_SYMBOL_GPL(dm_btree_insert);
 740
 741 int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root,
 742                            uint64_t *keys, void *value, dm_block_t *new_root,
 743                            int *inserted)
 744                            __dm_written_to_disk(value)
 745 {
 746         return insert(info, root, keys, value, new_root, inserted);
 747 }
 748 EXPORT_SYMBOL_GPL(dm_btree_insert_notify);
 749
 750 /*----------------------------------------------------------------*/
 751
 752 static int find_highest_key(struct ro_spine *s, dm_block_t block,
 753                             uint64_t *result_key, dm_block_t *next_block)
 754 {
 755         int i, r;
 756         uint32_t flags;
 757
 758         do {
 759                 r = ro_step(s, block);
 760                 if (r < 0)
 761                         return r;
 762
 763                 flags = le32_to_cpu(ro_node(s)->header.flags);
 764                 i = le32_to_cpu(ro_node(s)->header.nr_entries);
 765                 if (!i)
 766                         return -ENODATA;
 767                 else
 768                         i--;
 769
 770                 *result_key = le64_to_cpu(ro_node(s)->keys[i]);
 771                 if (next_block || flags & INTERNAL_NODE)
 772                         block = value64(ro_node(s), i);
 773
 774         } while (flags & INTERNAL_NODE);
 775
 776         if (next_block)
 777                 *next_block = block;
 778         return 0;
 779 }
 780
 781 int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
 782                               uint64_t *result_keys)
 783 {
 784         int r = 0, count = 0, level;
 785         struct ro_spine spine;
 786
 787         init_ro_spine(&spine, info);
 788         for (level = 0; level < info->levels; level++) {
 789                 r = find_highest_key(&spine, root, result_keys + level,
 790                                      level == info->levels - 1 ? NULL : &root);
 791                 if (r == -ENODATA) {
 792                         r = 0;
 793                         break;
 794
 795                 } else if (r)
 796                         break;
 797
 798                 count++;
 799         }
 800         exit_ro_spine(&spine);
 801
 802         return r ? r : count;
 803 }
 804 EXPORT_SYMBOL_GPL(dm_btree_find_highest_key);