fs/btrfs/ctree.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include "kerncompat.h"
   4 #include "radix-tree.h"
   5 #include "ctree.h"
   6 #include "disk-io.h"
   7 #include "print-tree.h"
   8
   9 int split_node(struct ctree_root *root, struct ctree_path *path, int level);
  10 int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size);
  11 int push_node_left(struct ctree_root *root, struct ctree_path *path, int level);
  12 int push_node_right(struct ctree_root *root,
  13                     struct ctree_path *path, int level);
  14 int del_ptr(struct ctree_root *root, struct ctree_path *path, int level);
  15
  16 inline void init_path(struct ctree_path *p)
  17 {
  18         memset(p, 0, sizeof(*p));
  19 }
  20
  21 void release_path(struct ctree_root *root, struct ctree_path *p)
  22 {
  23         int i;
  24         for (i = 0; i < MAX_LEVEL; i++) {
  25                 if (!p->nodes[i])
  26                         break;
  27                 tree_block_release(root, p->nodes[i]);
  28         }
  29 }
  30
  31 /*
  32  * The leaf data grows from end-to-front in the node.
  33  * this returns the address of the start of the last item,
  34  * which is the stop of the leaf data stack
  35  */
  36 static inline unsigned int leaf_data_end(struct leaf *leaf)
  37 {
  38         unsigned int nr = leaf->header.nritems;
  39         if (nr == 0)
  40                 return sizeof(leaf->data);
  41         return leaf->items[nr-1].offset;
  42 }
  43
  44 /*
  45  * The space between the end of the leaf items and
  46  * the start of the leaf data.  IOW, how much room
  47  * the leaf has left for both items and data
  48  */
  49 int leaf_free_space(struct leaf *leaf)
  50 {
  51         int data_end = leaf_data_end(leaf);
  52         int nritems = leaf->header.nritems;
  53         char *items_end = (char *)(leaf->items + nritems + 1);
  54         return (char *)(leaf->data + data_end) - (char *)items_end;
  55 }
  56
  57 /*
  58  * compare two keys in a memcmp fashion
  59  */
  60 int comp_keys(struct key *k1, struct key *k2)
  61 {
  62         if (k1->objectid > k2->objectid)
  63                 return 1;
  64         if (k1->objectid < k2->objectid)
  65                 return -1;
  66         if (k1->flags > k2->flags)
  67                 return 1;
  68         if (k1->flags < k2->flags)
  69                 return -1;
  70         if (k1->offset > k2->offset)
  71                 return 1;
  72         if (k1->offset < k2->offset)
  73                 return -1;
  74         return 0;
  75 }
  76
  77 /*
  78  * search for key in the array p.  items p are item_size apart
  79  * and there are 'max' items in p
  80  * the slot in the array is returned via slot, and it points to
  81  * the place where you would insert key if it is not found in
  82  * the array.
  83  *
  84  * slot may point to max if the key is bigger than all of the keys
  85  */
  86 int generic_bin_search(char *p, int item_size, struct key *key,
  87                        int max, int *slot)
  88 {
  89         int low = 0;
  90         int high = max;
  91         int mid;
  92         int ret;
  93         struct key *tmp;
  94
  95         while(low < high) {
  96                 mid = (low + high) / 2;
  97                 tmp = (struct key *)(p + mid * item_size);
  98                 ret = comp_keys(tmp, key);
  99
 100                 if (ret < 0)
 101                         low = mid + 1;
 102                 else if (ret > 0)
 103                         high = mid;
 104                 else {
 105                         *slot = mid;
 106                         return 0;
 107                 }
 108         }
 109         *slot = low;
 110         return 1;
 111 }
 112
 113 int bin_search(struct node *c, struct key *key, int *slot)
 114 {
 115         if (is_leaf(c->header.flags)) {
 116                 struct leaf *l = (struct leaf *)c;
 117                 return generic_bin_search((void *)l->items, sizeof(struct item),
 118                                           key, c->header.nritems, slot);
 119         } else {
 120                 return generic_bin_search((void *)c->keys, sizeof(struct key),
 121                                           key, c->header.nritems, slot);
 122         }
 123         return -1;
 124 }
 125
 126 /*
 127  * look for key in the tree.  path is filled in with nodes along the way
 128  * if key is found, we return zero and you can find the item in the leaf
 129  * level of the path (level 0)
 130  *
 131  * If the key isn't found, the path points to the slot where it should
 132  * be inserted.
 133  */
 134 int search_slot(struct ctree_root *root, struct key *key,
 135                 struct ctree_path *p, int ins_len)
 136 {
 137         struct tree_buffer *b = root->node;
 138         struct node *c;
 139         int slot;
 140         int ret;
 141         int level;
 142
 143         b->count++;
 144         while (b) {
 145                 c = &b->node;
 146                 level = node_level(c->header.flags);
 147                 p->nodes[level] = b;
 148                 ret = bin_search(c, key, &slot);
 149                 if (!is_leaf(c->header.flags)) {
 150                         if (ret && slot > 0)
 151                                 slot -= 1;
 152                         p->slots[level] = slot;
 153                         if (ins_len > 0 &&
 154                             c->header.nritems == NODEPTRS_PER_BLOCK) {
 155                                 int sret = split_node(root, p, level);
 156                                 BUG_ON(sret > 0);
 157                                 if (sret)
 158                                         return sret;
 159                                 b = p->nodes[level];
 160                                 c = &b->node;
 161                                 slot = p->slots[level];
 162                         } else if (ins_len < 0 &&
 163                                    c->header.nritems <= NODEPTRS_PER_BLOCK/4) {
 164                                 u64 blocknr = b->blocknr;
 165                                 slot = p->slots[level +1];
 166                                 b->count++;
 167                                 if (push_node_left(root, p, level))
 168                                         push_node_right(root, p, level);
 169                                 if (c->header.nritems == 0 &&
 170                                     level < MAX_LEVEL - 1 &&
 171                                     p->nodes[level + 1]) {
 172                                         int tslot = p->slots[level + 1];
 173
 174                                         p->slots[level + 1] = slot;
 175                                         del_ptr(root, p, level + 1);
 176                                         p->slots[level + 1] = tslot;
 177                                         tree_block_release(root, b);
 178                                         free_extent(root, blocknr, 1);
 179                                 } else {
 180                                         tree_block_release(root, b);
 181                                 }
 182                                 b = p->nodes[level];
 183                                 c = &b->node;
 184                                 slot = p->slots[level];
 185                         }
 186                         b = read_tree_block(root, c->blockptrs[slot]);
 187                         continue;
 188                 } else {
 189                         struct leaf *l = (struct leaf *)c;
 190                         p->slots[level] = slot;
 191                         if (ins_len > 0 && leaf_free_space(l) <
 192                             sizeof(struct item) + ins_len) {
 193                                 int sret = split_leaf(root, p, ins_len);
 194                                 BUG_ON(sret > 0);
 195                                 if (sret)
 196                                         return sret;
 197                         }
 198                         return ret;
 199                 }
 200         }
 201         return -1;
 202 }
 203
 204 /*
 205  * adjust the pointers going up the tree, starting at level
 206  * making sure the right key of each node is points to 'key'.
 207  * This is used after shifting pointers to the left, so it stops
 208  * fixing up pointers when a given leaf/node is not in slot 0 of the
 209  * higher levels
 210  */
 211 static void fixup_low_keys(struct ctree_root *root,
 212                            struct ctree_path *path, struct key *key,
 213                            int level)
 214 {
 215         int i;
 216         for (i = level; i < MAX_LEVEL; i++) {
 217                 struct node *t;
 218                 int tslot = path->slots[i];
 219                 if (!path->nodes[i])
 220                         break;
 221                 t = &path->nodes[i]->node;
 222                 memcpy(t->keys + tslot, key, sizeof(*key));
 223                 write_tree_block(root, path->nodes[i]);
 224                 if (tslot != 0)
 225                         break;
 226         }
 227 }
 228
 229 /*
 230  * try to push data from one node into the next node left in the
 231  * tree.  The src node is found at specified level in the path.
 232  * If some bytes were pushed, return 0, otherwise return 1.
 233  *
 234  * Lower nodes/leaves in the path are not touched, higher nodes may
 235  * be modified to reflect the push.
 236  *
 237  * The path is altered to reflect the push.
 238  */
 239 int push_node_left(struct ctree_root *root, struct ctree_path *path, int level)
 240 {
 241         int slot;
 242         struct node *left;
 243         struct node *right;
 244         int push_items = 0;
 245         int left_nritems;
 246         int right_nritems;
 247         struct tree_buffer *t;
 248         struct tree_buffer *right_buf;
 249
 250         if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0)
 251                 return 1;
 252         slot = path->slots[level + 1];
 253         if (slot == 0)
 254                 return 1;
 255
 256         t = read_tree_block(root,
 257                             path->nodes[level + 1]->node.blockptrs[slot - 1]);
 258         left = &t->node;
 259         right_buf = path->nodes[level];
 260         right = &right_buf->node;
 261         left_nritems = left->header.nritems;
 262         right_nritems = right->header.nritems;
 263         push_items = NODEPTRS_PER_BLOCK - (left_nritems + 1);
 264         if (push_items <= 0) {
 265                 tree_block_release(root, t);
 266                 return 1;
 267         }
 268
 269         if (right_nritems < push_items)
 270                 push_items = right_nritems;
 271         memcpy(left->keys + left_nritems, right->keys,
 272                 push_items * sizeof(struct key));
 273         memcpy(left->blockptrs + left_nritems, right->blockptrs,
 274                 push_items * sizeof(u64));
 275         memmove(right->keys, right->keys + push_items,
 276                 (right_nritems - push_items) * sizeof(struct key));
 277         memmove(right->blockptrs, right->blockptrs + push_items,
 278                 (right_nritems - push_items) * sizeof(u64));
 279         right->header.nritems -= push_items;
 280         left->header.nritems += push_items;
 281
 282         /* adjust the pointers going up the tree */
 283         fixup_low_keys(root, path, right->keys, level + 1);
 284
 285         write_tree_block(root, t);
 286         write_tree_block(root, right_buf);
 287
 288         /* then fixup the leaf pointer in the path */
 289         if (path->slots[level] < push_items) {
 290                 path->slots[level] += left_nritems;
 291                 tree_block_release(root, path->nodes[level]);
 292                 path->nodes[level] = t;
 293                 path->slots[level + 1] -= 1;
 294         } else {
 295                 path->slots[level] -= push_items;
 296                 tree_block_release(root, t);
 297         }
 298         return 0;
 299 }
 300
 301 /*
 302  * try to push data from one node into the next node right in the
 303  * tree.  The src node is found at specified level in the path.
 304  * If some bytes were pushed, return 0, otherwise return 1.
 305  *
 306  * Lower nodes/leaves in the path are not touched, higher nodes may
 307  * be modified to reflect the push.
 308  *
 309  * The path is altered to reflect the push.
 310  */
 311 int push_node_right(struct ctree_root *root, struct ctree_path *path, int level)
 312 {
 313         int slot;
 314         struct tree_buffer *t;
 315         struct tree_buffer *src_buffer;
 316         struct node *dst;
 317         struct node *src;
 318         int push_items = 0;
 319         int dst_nritems;
 320         int src_nritems;
 321
 322         /* can't push from the root */
 323         if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0)
 324                 return 1;
 325
 326         /* only try to push inside the node higher up */
 327         slot = path->slots[level + 1];
 328         if (slot == NODEPTRS_PER_BLOCK - 1)
 329                 return 1;
 330
 331         if (slot >= path->nodes[level + 1]->node.header.nritems -1)
 332                 return 1;
 333
 334         t = read_tree_block(root,
 335                             path->nodes[level + 1]->node.blockptrs[slot + 1]);
 336         dst = &t->node;
 337         src_buffer = path->nodes[level];
 338         src = &src_buffer->node;
 339         dst_nritems = dst->header.nritems;
 340         src_nritems = src->header.nritems;
 341         push_items = NODEPTRS_PER_BLOCK - (dst_nritems + 1);
 342         if (push_items <= 0) {
 343                 tree_block_release(root, t);
 344                 return 1;
 345         }
 346
 347         if (src_nritems < push_items)
 348                 push_items = src_nritems;
 349         memmove(dst->keys + push_items, dst->keys,
 350                 dst_nritems * sizeof(struct key));
 351         memcpy(dst->keys, src->keys + src_nritems - push_items,
 352                 push_items * sizeof(struct key));
 353
 354         memmove(dst->blockptrs + push_items, dst->blockptrs,
 355                 dst_nritems * sizeof(u64));
 356         memcpy(dst->blockptrs, src->blockptrs + src_nritems - push_items,
 357                 push_items * sizeof(u64));
 358
 359         src->header.nritems -= push_items;
 360         dst->header.nritems += push_items;
 361
 362         /* adjust the pointers going up the tree */
 363         memcpy(path->nodes[level + 1]->node.keys + path->slots[level + 1] + 1,
 364                 dst->keys, sizeof(struct key));
 365
 366         write_tree_block(root, path->nodes[level + 1]);
 367         write_tree_block(root, t);
 368         write_tree_block(root, src_buffer);
 369
 370         /* then fixup the pointers in the path */
 371         if (path->slots[level] >= src->header.nritems) {
 372                 path->slots[level] -= src->header.nritems;
 373                 tree_block_release(root, path->nodes[level]);
 374                 path->nodes[level] = t;
 375                 path->slots[level + 1] += 1;
 376         } else {
 377                 tree_block_release(root, t);
 378         }
 379         return 0;
 380 }
 381
 382 static int insert_new_root(struct ctree_root *root,
 383                            struct ctree_path *path, int level)
 384 {
 385         struct tree_buffer *t;
 386         struct node *lower;
 387         struct node *c;
 388         struct key *lower_key;
 389
 390         BUG_ON(path->nodes[level]);
 391         BUG_ON(path->nodes[level-1] != root->node);
 392
 393         t = alloc_free_block(root);
 394         c = &t->node;
 395         memset(c, 0, sizeof(c));
 396         c->header.nritems = 1;
 397         c->header.flags = node_level(level);
 398         c->header.blocknr = t->blocknr;
 399         c->header.parentid = root->node->node.header.parentid;
 400         lower = &path->nodes[level-1]->node;
 401         if (is_leaf(lower->header.flags))
 402                 lower_key = &((struct leaf *)lower)->items[0].key;
 403         else
 404                 lower_key = lower->keys;
 405         memcpy(c->keys, lower_key, sizeof(struct key));
 406         c->blockptrs[0] = path->nodes[level-1]->blocknr;
 407         /* the super has an extra ref to root->node */
 408         tree_block_release(root, root->node);
 409         root->node = t;
 410         t->count++;
 411         write_tree_block(root, t);
 412         path->nodes[level] = t;
 413         path->slots[level] = 0;
 414         return 0;
 415 }
 416
 417 /*
 418  * worker function to insert a single pointer in a node.
 419  * the node should have enough room for the pointer already
 420  * slot and level indicate where you want the key to go, and
 421  * blocknr is the block the key points to.
 422  */
 423 int insert_ptr(struct ctree_root *root,
 424                 struct ctree_path *path, struct key *key,
 425                 u64 blocknr, int slot, int level)
 426 {
 427         struct node *lower;
 428         int nritems;
 429
 430         BUG_ON(!path->nodes[level]);
 431         lower = &path->nodes[level]->node;
 432         nritems = lower->header.nritems;
 433         if (slot > nritems)
 434                 BUG();
 435         if (nritems == NODEPTRS_PER_BLOCK)
 436                 BUG();
 437         if (slot != nritems) {
 438                 memmove(lower->keys + slot + 1, lower->keys + slot,
 439                         (nritems - slot) * sizeof(struct key));
 440                 memmove(lower->blockptrs + slot + 1, lower->blockptrs + slot,
 441                         (nritems - slot) * sizeof(u64));
 442         }
 443         memcpy(lower->keys + slot, key, sizeof(struct key));
 444         lower->blockptrs[slot] = blocknr;
 445         lower->header.nritems++;
 446         if (lower->keys[1].objectid == 0)
 447                         BUG();
 448         write_tree_block(root, path->nodes[level]);
 449         return 0;
 450 }
 451
 452 int split_node(struct ctree_root *root, struct ctree_path *path, int level)
 453 {
 454         struct tree_buffer *t;
 455         struct node *c;
 456         struct tree_buffer *split_buffer;
 457         struct node *split;
 458         int mid;
 459         int ret;
 460
 461         ret = push_node_left(root, path, level);
 462         if (!ret)
 463                 return 0;
 464         ret = push_node_right(root, path, level);
 465         if (!ret)
 466                 return 0;
 467         t = path->nodes[level];
 468         c = &t->node;
 469         if (t == root->node) {
 470                 /* trying to split the root, lets make a new one */
 471                 ret = insert_new_root(root, path, level + 1);
 472                 if (ret)
 473                         return ret;
 474         }
 475         split_buffer = alloc_free_block(root);
 476         split = &split_buffer->node;
 477         split->header.flags = c->header.flags;
 478         split->header.blocknr = split_buffer->blocknr;
 479         split->header.parentid = root->node->node.header.parentid;
 480         mid = (c->header.nritems + 1) / 2;
 481         memcpy(split->keys, c->keys + mid,
 482                 (c->header.nritems - mid) * sizeof(struct key));
 483         memcpy(split->blockptrs, c->blockptrs + mid,
 484                 (c->header.nritems - mid) * sizeof(u64));
 485         split->header.nritems = c->header.nritems - mid;
 486         c->header.nritems = mid;
 487         write_tree_block(root, t);
 488         write_tree_block(root, split_buffer);
 489         insert_ptr(root, path, split->keys, split_buffer->blocknr,
 490                      path->slots[level + 1] + 1, level + 1);
 491         if (path->slots[level] >= mid) {
 492                 path->slots[level] -= mid;
 493                 tree_block_release(root, t);
 494                 path->nodes[level] = split_buffer;
 495                 path->slots[level + 1] += 1;
 496         } else {
 497                 tree_block_release(root, split_buffer);
 498         }
 499         return 0;
 500 }
 501
 502 /*
 503  * how many bytes are required to store the items in a leaf.  start
 504  * and nr indicate which items in the leaf to check.  This totals up the
 505  * space used both by the item structs and the item data
 506  */
 507 int leaf_space_used(struct leaf *l, int start, int nr)
 508 {
 509         int data_len;
 510         int end = start + nr - 1;
 511
 512         if (!nr)
 513                 return 0;
 514         data_len = l->items[start].offset + l->items[start].size;
 515         data_len = data_len - l->items[end].offset;
 516         data_len += sizeof(struct item) * nr;
 517         return data_len;
 518 }
 519
 520 /*
 521  * push some data in the path leaf to the left, trying to free up at
 522  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
 523  */
 524 int push_leaf_left(struct ctree_root *root, struct ctree_path *path,
 525                    int data_size)
 526 {
 527         struct tree_buffer *right_buf = path->nodes[0];
 528         struct leaf *right = &right_buf->leaf;
 529         struct tree_buffer *t;
 530         struct leaf *left;
 531         int slot;
 532         int i;
 533         int free_space;
 534         int push_space = 0;
 535         int push_items = 0;
 536         struct item *item;
 537         int old_left_nritems;
 538
 539         slot = path->slots[1];
 540         if (slot == 0) {
 541                 return 1;
 542         }
 543         if (!path->nodes[1]) {
 544                 return 1;
 545         }
 546         t = read_tree_block(root, path->nodes[1]->node.blockptrs[slot - 1]);
 547         left = &t->leaf;
 548         free_space = leaf_free_space(left);
 549         if (free_space < data_size + sizeof(struct item)) {
 550                 tree_block_release(root, t);
 551                 return 1;
 552         }
 553         for (i = 0; i < right->header.nritems; i++) {
 554                 item = right->items + i;
 555                 if (path->slots[0] == i)
 556                         push_space += data_size + sizeof(*item);
 557                 if (item->size + sizeof(*item) + push_space > free_space)
 558                         break;
 559                 push_items++;
 560                 push_space += item->size + sizeof(*item);
 561         }
 562         if (push_items == 0) {
 563                 tree_block_release(root, t);
 564                 return 1;
 565         }
 566         /* push data from right to left */
 567         memcpy(left->items + left->header.nritems,
 568                 right->items, push_items * sizeof(struct item));
 569         push_space = LEAF_DATA_SIZE - right->items[push_items -1].offset;
 570         memcpy(left->data + leaf_data_end(left) - push_space,
 571                 right->data + right->items[push_items - 1].offset,
 572                 push_space);
 573         old_left_nritems = left->header.nritems;
 574         BUG_ON(old_left_nritems < 0);
 575
 576         for(i = old_left_nritems; i < old_left_nritems + push_items; i++) {
 577                 left->items[i].offset -= LEAF_DATA_SIZE -
 578                         left->items[old_left_nritems -1].offset;
 579         }
 580         left->header.nritems += push_items;
 581
 582         /* fixup right node */
 583         push_space = right->items[push_items-1].offset - leaf_data_end(right);
 584         memmove(right->data + LEAF_DATA_SIZE - push_space, right->data +
 585                 leaf_data_end(right), push_space);
 586         memmove(right->items, right->items + push_items,
 587                 (right->header.nritems - push_items) * sizeof(struct item));
 588         right->header.nritems -= push_items;
 589         push_space = LEAF_DATA_SIZE;
 590
 591         for (i = 0; i < right->header.nritems; i++) {
 592                 right->items[i].offset = push_space - right->items[i].size;
 593                 push_space = right->items[i].offset;
 594         }
 595
 596         write_tree_block(root, t);
 597         write_tree_block(root, right_buf);
 598
 599         fixup_low_keys(root, path, &right->items[0].key, 1);
 600
 601         /* then fixup the leaf pointer in the path */
 602         if (path->slots[0] < push_items) {
 603                 path->slots[0] += old_left_nritems;
 604                 tree_block_release(root, path->nodes[0]);
 605                 path->nodes[0] = t;
 606                 path->slots[1] -= 1;
 607         } else {
 608                 tree_block_release(root, t);
 609                 path->slots[0] -= push_items;
 610         }
 611         BUG_ON(path->slots[0] < 0);
 612         return 0;
 613 }
 614
 615 /*
 616  * split the path's leaf in two, making sure there is at least data_size
 617  * available for the resulting leaf level of the path.
 618  */
 619 int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size)
 620 {
 621         struct tree_buffer *l_buf = path->nodes[0];
 622         struct leaf *l = &l_buf->leaf;
 623         int nritems;
 624         int mid;
 625         int slot;
 626         struct leaf *right;
 627         struct tree_buffer *right_buffer;
 628         int space_needed = data_size + sizeof(struct item);
 629         int data_copy_size;
 630         int rt_data_off;
 631         int i;
 632         int ret;
 633
 634         if (push_leaf_left(root, path, data_size) == 0) {
 635                 l_buf = path->nodes[0];
 636                 l = &l_buf->leaf;
 637                 if (leaf_free_space(l) >= sizeof(struct item) + data_size)
 638                         return 0;
 639         }
 640         if (!path->nodes[1]) {
 641                 ret = insert_new_root(root, path, 1);
 642                 if (ret)
 643                         return ret;
 644         }
 645         slot = path->slots[0];
 646         nritems = l->header.nritems;
 647         mid = (nritems + 1)/ 2;
 648
 649         right_buffer = alloc_free_block(root);
 650         BUG_ON(!right_buffer);
 651         BUG_ON(mid == nritems);
 652         right = &right_buffer->leaf;
 653         memset(right, 0, sizeof(*right));
 654         if (mid <= slot) {
 655                 if (leaf_space_used(l, mid, nritems - mid) + space_needed >
 656                         LEAF_DATA_SIZE)
 657                         BUG();
 658         } else {
 659                 if (leaf_space_used(l, 0, mid + 1) + space_needed >
 660                         LEAF_DATA_SIZE)
 661                         BUG();
 662         }
 663         right->header.nritems = nritems - mid;
 664         right->header.blocknr = right_buffer->blocknr;
 665         right->header.flags = node_level(0);
 666         right->header.parentid = root->node->node.header.parentid;
 667         data_copy_size = l->items[mid].offset + l->items[mid].size -
 668                          leaf_data_end(l);
 669         memcpy(right->items, l->items + mid,
 670                (nritems - mid) * sizeof(struct item));
 671         memcpy(right->data + LEAF_DATA_SIZE - data_copy_size,
 672                l->data + leaf_data_end(l), data_copy_size);
 673         rt_data_off = LEAF_DATA_SIZE -
 674                      (l->items[mid].offset + l->items[mid].size);
 675
 676         for (i = 0; i < right->header.nritems; i++)
 677                 right->items[i].offset += rt_data_off;
 678
 679         l->header.nritems = mid;
 680         ret = insert_ptr(root, path, &right->items[0].key,
 681                           right_buffer->blocknr, path->slots[1] + 1, 1);
 682         write_tree_block(root, right_buffer);
 683         write_tree_block(root, l_buf);
 684
 685         BUG_ON(path->slots[0] != slot);
 686         if (mid <= slot) {
 687                 tree_block_release(root, path->nodes[0]);
 688                 path->nodes[0] = right_buffer;
 689                 path->slots[0] -= mid;
 690                 path->slots[1] += 1;
 691         } else
 692                 tree_block_release(root, right_buffer);
 693         BUG_ON(path->slots[0] < 0);
 694         return ret;
 695 }
 696
 697 /*
 698  * Given a key and some data, insert an item into the tree.
 699  * This does all the path init required, making room in the tree if needed.
 700  */
 701 int insert_item(struct ctree_root *root, struct key *key,
 702                           void *data, int data_size)
 703 {
 704         int ret;
 705         int slot;
 706         int slot_orig;
 707         struct leaf *leaf;
 708         struct tree_buffer *leaf_buf;
 709         unsigned int nritems;
 710         unsigned int data_end;
 711         struct ctree_path path;
 712
 713         /* create a root if there isn't one */
 714         if (!root->node)
 715                 BUG();
 716         init_path(&path);
 717         ret = search_slot(root, key, &path, data_size);
 718         if (ret == 0) {
 719                 release_path(root, &path);
 720                 return -EEXIST;
 721         }
 722
 723         slot_orig = path.slots[0];
 724         leaf_buf = path.nodes[0];
 725         leaf = &leaf_buf->leaf;
 726
 727         nritems = leaf->header.nritems;
 728         data_end = leaf_data_end(leaf);
 729
 730         if (leaf_free_space(leaf) <  sizeof(struct item) + data_size)
 731                 BUG();
 732
 733         slot = path.slots[0];
 734         BUG_ON(slot < 0);
 735         if (slot == 0)
 736                 fixup_low_keys(root, &path, key, 1);
 737         if (slot != nritems) {
 738                 int i;
 739                 unsigned int old_data = leaf->items[slot].offset +
 740                                         leaf->items[slot].size;
 741
 742                 /*
 743                  * item0..itemN ... dataN.offset..dataN.size .. data0.size
 744                  */
 745                 /* first correct the data pointers */
 746                 for (i = slot; i < nritems; i++)
 747                         leaf->items[i].offset -= data_size;
 748
 749                 /* shift the items */
 750                 memmove(leaf->items + slot + 1, leaf->items + slot,
 751                         (nritems - slot) * sizeof(struct item));
 752
 753                 /* shift the data */
 754                 memmove(leaf->data + data_end - data_size, leaf->data +
 755                         data_end, old_data - data_end);
 756                 data_end = old_data;
 757         }
 758         /* copy the new data in */
 759         memcpy(&leaf->items[slot].key, key, sizeof(struct key));
 760         leaf->items[slot].offset = data_end - data_size;
 761         leaf->items[slot].size = data_size;
 762         memcpy(leaf->data + data_end - data_size, data, data_size);
 763         leaf->header.nritems += 1;
 764         write_tree_block(root, leaf_buf);
 765         if (leaf_free_space(leaf) < 0)
 766                 BUG();
 767         release_path(root, &path);
 768         return 0;
 769 }
 770
 771 /*
 772  * delete the pointer from a given node.
 773  *
 774  * If the delete empties a node, the node is removed from the tree,
 775  * continuing all the way the root if required.  The root is converted into
 776  * a leaf if all the nodes are emptied.
 777  */
 778 int del_ptr(struct ctree_root *root, struct ctree_path *path, int level)
 779 {
 780         int slot;
 781         struct tree_buffer *t;
 782         struct node *node;
 783         int nritems;
 784         u64 blocknr;
 785
 786         while(1) {
 787                 t = path->nodes[level];
 788                 if (!t)
 789                         break;
 790                 node = &t->node;
 791                 slot = path->slots[level];
 792                 nritems = node->header.nritems;
 793
 794                 if (slot != nritems -1) {
 795                         memmove(node->keys + slot, node->keys + slot + 1,
 796                                 sizeof(struct key) * (nritems - slot - 1));
 797                         memmove(node->blockptrs + slot,
 798                                 node->blockptrs + slot + 1,
 799                                 sizeof(u64) * (nritems - slot - 1));
 800                 }
 801                 node->header.nritems--;
 802                 write_tree_block(root, t);
 803                 blocknr = t->blocknr;
 804                 if (node->header.nritems != 0) {
 805                         if (slot == 0)
 806                                 fixup_low_keys(root, path, node->keys,
 807                                                level + 1);
 808                         break;
 809                 }
 810                 if (t == root->node) {
 811                         /* just turn the root into a leaf and break */
 812                         root->node->node.header.flags = node_level(0);
 813                         write_tree_block(root, t);
 814                         break;
 815                 }
 816                 level++;
 817                 free_extent(root, blocknr, 1);
 818                 if (!path->nodes[level])
 819                         BUG();
 820         }
 821         return 0;
 822 }
 823
 824 /*
 825  * delete the item at the leaf level in path.  If that empties
 826  * the leaf, remove it from the tree
 827  */
 828 int del_item(struct ctree_root *root, struct ctree_path *path)
 829 {
 830         int slot;
 831         struct leaf *leaf;
 832         struct tree_buffer *leaf_buf;
 833         int doff;
 834         int dsize;
 835
 836         leaf_buf = path->nodes[0];
 837         leaf = &leaf_buf->leaf;
 838         slot = path->slots[0];
 839         doff = leaf->items[slot].offset;
 840         dsize = leaf->items[slot].size;
 841
 842         if (slot != leaf->header.nritems - 1) {
 843                 int i;
 844                 int data_end = leaf_data_end(leaf);
 845                 memmove(leaf->data + data_end + dsize,
 846                         leaf->data + data_end,
 847                         doff - data_end);
 848                 for (i = slot + 1; i < leaf->header.nritems; i++)
 849                         leaf->items[i].offset += dsize;
 850                 memmove(leaf->items + slot, leaf->items + slot + 1,
 851                         sizeof(struct item) *
 852                         (leaf->header.nritems - slot - 1));
 853         }
 854         leaf->header.nritems -= 1;
 855         /* delete the leaf if we've emptied it */
 856         if (leaf->header.nritems == 0) {
 857                 if (leaf_buf == root->node) {
 858                         leaf->header.flags = node_level(0);
 859                         write_tree_block(root, leaf_buf);
 860                 } else {
 861                         del_ptr(root, path, 1);
 862                         free_extent(root, leaf_buf->blocknr, 1);
 863                 }
 864         } else {
 865                 int used = leaf_space_used(leaf, 0, leaf->header.nritems);
 866                 if (slot == 0)
 867                         fixup_low_keys(root, path, &leaf->items[0].key, 1);
 868                 write_tree_block(root, leaf_buf);
 869                 /* delete the leaf if it is mostly empty */
 870                 if (used < LEAF_DATA_SIZE / 3) {
 871                         /* push_leaf_left fixes the path.
 872                          * make sure the path still points to our leaf
 873                          * for possible call to del_ptr below
 874                          */
 875                         slot = path->slots[1];
 876                         leaf_buf->count++;
 877                         push_leaf_left(root, path, 1);
 878                         if (leaf->header.nritems == 0) {
 879                                 u64 blocknr = leaf_buf->blocknr;
 880                                 path->slots[1] = slot;
 881                                 del_ptr(root, path, 1);
 882                                 tree_block_release(root, leaf_buf);
 883                                 free_extent(root, blocknr, 1);
 884                         } else {
 885                                 tree_block_release(root, leaf_buf);
 886                         }
 887                 }
 888         }
 889         return 0;
 890 }
 891
 892 int next_leaf(struct ctree_root *root, struct ctree_path *path)
 893 {
 894         int slot;
 895         int level = 1;
 896         u64 blocknr;
 897         struct tree_buffer *c;
 898         struct tree_buffer *next = NULL;
 899
 900         while(level < MAX_LEVEL) {
 901                 if (!path->nodes[level])
 902                         return -1;
 903                 slot = path->slots[level] + 1;
 904                 c = path->nodes[level];
 905                 if (slot >= c->node.header.nritems) {
 906                         level++;
 907                         continue;
 908                 }
 909                 blocknr = c->node.blockptrs[slot];
 910                 if (next)
 911                         tree_block_release(root, next);
 912                 next = read_tree_block(root, blocknr);
 913                 break;
 914         }
 915         path->slots[level] = slot;
 916         while(1) {
 917                 level--;
 918                 c = path->nodes[level];
 919                 tree_block_release(root, c);
 920                 path->nodes[level] = next;
 921                 path->slots[level] = 0;
 922                 if (!level)
 923                         break;
 924                 next = read_tree_block(root, next->node.blockptrs[0]);
 925         }
 926         return 0;
 927 }
 928
 929 /* for testing only */
 930 int next_key(int i, int max_key) {
 931         return rand() % max_key;
 932         // return i;
 933 }
 934
 935 int main() {
 936         struct ctree_root *root;
 937         struct key ins;
 938         struct key last = { (u64)-1, 0, 0};
 939         char *buf;
 940         int i;
 941         int num;
 942         int ret;
 943         int run_size = 20000000;
 944         int max_key =  100000000;
 945         int tree_size = 0;
 946         struct ctree_path path;
 947         struct ctree_super_block super;
 948
 949         radix_tree_init();
 950
 951
 952         root = open_ctree("dbfile", &super);
 953
 954         srand(55);
 955         for (i = 0; i < run_size; i++) {
 956                 buf = malloc(64);
 957                 num = next_key(i, max_key);
 958                 // num = i;
 959                 sprintf(buf, "string-%d", num);
 960                 if (i % 10000 == 0)
 961                         printf("insert %d:%d\n", num, i);
 962                 ins.objectid = num;
 963                 ins.offset = 0;
 964                 ins.flags = 0;
 965                 ret = insert_item(root, &ins, buf, strlen(buf));
 966                 if (!ret)
 967                         tree_size++;
 968                 free(buf);
 969         }
 970         write_ctree_super(root, &super);
 971         close_ctree(root);
 972
 973         root = open_ctree("dbfile", &super);
 974         printf("starting search\n");
 975         srand(55);
 976         for (i = 0; i < run_size; i++) {
 977                 num = next_key(i, max_key);
 978                 ins.objectid = num;
 979                 init_path(&path);
 980                 if (i % 10000 == 0)
 981                         printf("search %d:%d\n", num, i);
 982                 ret = search_slot(root, &ins, &path, 0);
 983                 if (ret) {
 984                         print_tree(root, root->node);
 985                         printf("unable to find %d\n", num);
 986                         exit(1);
 987                 }
 988                 release_path(root, &path);
 989         }
 990         write_ctree_super(root, &super);
 991         close_ctree(root);
 992         root = open_ctree("dbfile", &super);
 993         printf("node %p level %d total ptrs %d free spc %lu\n", root->node,
 994                 node_level(root->node->node.header.flags),
 995                 root->node->node.header.nritems,
 996                 NODEPTRS_PER_BLOCK - root->node->node.header.nritems);
 997         printf("all searches good, deleting some items\n");
 998         i = 0;
 999         srand(55);
1000         for (i = 0 ; i < run_size/4; i++) {
1001                 num = next_key(i, max_key);
1002                 ins.objectid = num;
1003                 init_path(&path);
1004                 ret = search_slot(root, &ins, &path, -1);
1005                 if (!ret) {
1006                         if (i % 10000 == 0)
1007                                 printf("del %d:%d\n", num, i);
1008                         ret = del_item(root, &path);
1009                         if (ret != 0)
1010                                 BUG();
1011                         tree_size--;
1012                 }
1013                 release_path(root, &path);
1014         }
1015         write_ctree_super(root, &super);
1016         close_ctree(root);
1017         root = open_ctree("dbfile", &super);
1018         srand(128);
1019         for (i = 0; i < run_size; i++) {
1020                 buf = malloc(64);
1021                 num = next_key(i, max_key);
1022                 sprintf(buf, "string-%d", num);
1023                 ins.objectid = num;
1024                 if (i % 10000 == 0)
1025                         printf("insert %d:%d\n", num, i);
1026                 ret = insert_item(root, &ins, buf, strlen(buf));
1027                 if (!ret)
1028                         tree_size++;
1029                 free(buf);
1030         }
1031         write_ctree_super(root, &super);
1032         close_ctree(root);
1033         root = open_ctree("dbfile", &super);
1034         srand(128);
1035         printf("starting search2\n");
1036         for (i = 0; i < run_size; i++) {
1037                 num = next_key(i, max_key);
1038                 ins.objectid = num;
1039                 init_path(&path);
1040                 if (i % 10000 == 0)
1041                         printf("search %d:%d\n", num, i);
1042                 ret = search_slot(root, &ins, &path, 0);
1043                 if (ret) {
1044                         print_tree(root, root->node);
1045                         printf("unable to find %d\n", num);
1046                         exit(1);
1047                 }
1048                 release_path(root, &path);
1049         }
1050         printf("starting big long delete run\n");
1051         while(root->node && root->node->node.header.nritems > 0) {
1052                 struct leaf *leaf;
1053                 int slot;
1054                 ins.objectid = (u64)-1;
1055                 init_path(&path);
1056                 ret = search_slot(root, &ins, &path, -1);
1057                 if (ret == 0)
1058                         BUG();
1059
1060                 leaf = &path.nodes[0]->leaf;
1061                 slot = path.slots[0];
1062                 if (slot != leaf->header.nritems)
1063                         BUG();
1064                 while(path.slots[0] > 0) {
1065                         path.slots[0] -= 1;
1066                         slot = path.slots[0];
1067                         leaf = &path.nodes[0]->leaf;
1068
1069                         if (comp_keys(&last, &leaf->items[slot].key) <= 0)
1070                                 BUG();
1071                         memcpy(&last, &leaf->items[slot].key, sizeof(last));
1072                         if (tree_size % 10000 == 0)
1073                                 printf("big del %d:%d\n", tree_size, i);
1074                         ret = del_item(root, &path);
1075                         if (ret != 0) {
1076                                 printf("del_item returned %d\n", ret);
1077                                 BUG();
1078                         }
1079                         tree_size--;
1080                 }
1081                 release_path(root, &path);
1082         }
1083         printf("tree size is now %d\n", tree_size);
1084         printf("map tree\n");
1085         write_ctree_super(root, &super);
1086         close_ctree(root);
1087         return 0;
1088 }