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
   8 #define SEARCH_READ 0
   9 #define SEARCH_WRITE 1
  10
  11 #define CTREE_EXTENT_PENDING 0
  12
  13 int split_node(struct ctree_root *root, struct ctree_path *path, int level);
  14 int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size);
  15 struct tree_buffer *alloc_free_block(struct ctree_root *root);
  16 int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks);
  17
  18 static inline void init_path(struct ctree_path *p)
  19 {
  20         memset(p, 0, sizeof(*p));
  21 }
  22
  23 static void release_path(struct ctree_root *root, struct ctree_path *p)
  24 {
  25         int i;
  26         for (i = 0; i < MAX_LEVEL; i++) {
  27                 if (!p->nodes[i])
  28                         break;
  29                 tree_block_release(root, p->nodes[i]);
  30         }
  31 }
  32
  33 /*
  34  * The leaf data grows from end-to-front in the node.
  35  * this returns the address of the start of the last item,
  36  * which is the stop of the leaf data stack
  37  */
  38 static inline unsigned int leaf_data_end(struct leaf *leaf)
  39 {
  40         unsigned int nr = leaf->header.nritems;
  41         if (nr == 0)
  42                 return sizeof(leaf->data);
  43         return leaf->items[nr-1].offset;
  44 }
  45
  46 /*
  47  * The space between the end of the leaf items and
  48  * the start of the leaf data.  IOW, how much room
  49  * the leaf has left for both items and data
  50  */
  51 static inline int leaf_free_space(struct leaf *leaf)
  52 {
  53         int data_end = leaf_data_end(leaf);
  54         int nritems = leaf->header.nritems;
  55         char *items_end = (char *)(leaf->items + nritems + 1);
  56         return (char *)(leaf->data + data_end) - (char *)items_end;
  57 }
  58
  59 /*
  60  * compare two keys in a memcmp fashion
  61  */
  62 int comp_keys(struct key *k1, struct key *k2)
  63 {
  64         if (k1->objectid > k2->objectid)
  65                 return 1;
  66         if (k1->objectid < k2->objectid)
  67                 return -1;
  68         if (k1->flags > k2->flags)
  69                 return 1;
  70         if (k1->flags < k2->flags)
  71                 return -1;
  72         if (k1->offset > k2->offset)
  73                 return 1;
  74         if (k1->offset < k2->offset)
  75                 return -1;
  76         return 0;
  77 }
  78
  79 /*
  80  * search for key in the array p.  items p are item_size apart
  81  * and there are 'max' items in p
  82  * the slot in the array is returned via slot, and it points to
  83  * the place where you would insert key if it is not found in
  84  * the array.
  85  *
  86  * slot may point to max if the key is bigger than all of the keys
  87  */
  88 int generic_bin_search(char *p, int item_size, struct key *key,
  89                        int max, int *slot)
  90 {
  91         int low = 0;
  92         int high = max;
  93         int mid;
  94         int ret;
  95         struct key *tmp;
  96
  97         while(low < high) {
  98                 mid = (low + high) / 2;
  99                 tmp = (struct key *)(p + mid * item_size);
 100                 ret = comp_keys(tmp, key);
 101
 102                 if (ret < 0)
 103                         low = mid + 1;
 104                 else if (ret > 0)
 105                         high = mid;
 106                 else {
 107                         *slot = mid;
 108                         return 0;
 109                 }
 110         }
 111         *slot = low;
 112         return 1;
 113 }
 114
 115 int bin_search(struct node *c, struct key *key, int *slot)
 116 {
 117         if (is_leaf(c->header.flags)) {
 118                 struct leaf *l = (struct leaf *)c;
 119                 return generic_bin_search((void *)l->items, sizeof(struct item),
 120                                           key, c->header.nritems, slot);
 121         } else {
 122                 return generic_bin_search((void *)c->keys, sizeof(struct key),
 123                                           key, c->header.nritems, slot);
 124         }
 125         return -1;
 126 }
 127
 128 /*
 129  * look for key in the tree.  path is filled in with nodes along the way
 130  * if key is found, we return zero and you can find the item in the leaf
 131  * level of the path (level 0)
 132  *
 133  * If the key isn't found, the path points to the slot where it should
 134  * be inserted.
 135  */
 136 int search_slot(struct ctree_root *root, struct key *key, struct ctree_path *p, int ins_len)
 137 {
 138         struct tree_buffer *b = root->node;
 139         struct node *c;
 140         int slot;
 141         int ret;
 142         int level;
 143
 144         b->count++;
 145         while (b) {
 146                 c = &b->node;
 147                 level = node_level(c->header.flags);
 148                 p->nodes[level] = b;
 149                 ret = bin_search(c, key, &slot);
 150                 if (!is_leaf(c->header.flags)) {
 151                         if (ret && slot > 0)
 152                                 slot -= 1;
 153                         p->slots[level] = slot;
 154                         if (ins_len && 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                         }
 163                         b = read_tree_block(root, c->blockptrs[slot]);
 164                         continue;
 165                 } else {
 166                         struct leaf *l = (struct leaf *)c;
 167                         p->slots[level] = slot;
 168                         if (ins_len && leaf_free_space(l) <  sizeof(struct item) + ins_len) {
 169                                 int sret = split_leaf(root, p, ins_len);
 170                                 BUG_ON(sret > 0);
 171                                 if (sret)
 172                                         return sret;
 173                         }
 174                         return ret;
 175                 }
 176         }
 177         return -1;
 178 }
 179
 180 /*
 181  * adjust the pointers going up the tree, starting at level
 182  * making sure the right key of each node is points to 'key'.
 183  * This is used after shifting pointers to the left, so it stops
 184  * fixing up pointers when a given leaf/node is not in slot 0 of the
 185  * higher levels
 186  */
 187 static void fixup_low_keys(struct ctree_root *root,
 188                            struct ctree_path *path, struct key *key,
 189                            int level)
 190 {
 191         int i;
 192         for (i = level; i < MAX_LEVEL; i++) {
 193                 struct node *t;
 194                 int tslot = path->slots[i];
 195                 if (!path->nodes[i])
 196                         break;
 197                 t = &path->nodes[i]->node;
 198                 memcpy(t->keys + tslot, key, sizeof(*key));
 199                 write_tree_block(root, path->nodes[i]);
 200                 if (tslot != 0)
 201                         break;
 202         }
 203 }
 204
 205 /*
 206  * try to push data from one node into the next node left in the
 207  * tree.  The src node is found at specified level in the path.
 208  * If some bytes were pushed, return 0, otherwise return 1.
 209  *
 210  * Lower nodes/leaves in the path are not touched, higher nodes may
 211  * be modified to reflect the push.
 212  *
 213  * The path is altered to reflect the push.
 214  */
 215 int push_node_left(struct ctree_root *root, struct ctree_path *path, int level)
 216 {
 217         int slot;
 218         struct node *left;
 219         struct node *right;
 220         int push_items = 0;
 221         int left_nritems;
 222         int right_nritems;
 223         struct tree_buffer *t;
 224         struct tree_buffer *right_buf;
 225
 226         if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0)
 227                 return 1;
 228         slot = path->slots[level + 1];
 229         if (slot == 0)
 230                 return 1;
 231
 232         t = read_tree_block(root,
 233                             path->nodes[level + 1]->node.blockptrs[slot - 1]);
 234         left = &t->node;
 235         right_buf = path->nodes[level];
 236         right = &right_buf->node;
 237         left_nritems = left->header.nritems;
 238         right_nritems = right->header.nritems;
 239         push_items = NODEPTRS_PER_BLOCK - (left_nritems + 1);
 240         if (push_items <= 0) {
 241                 tree_block_release(root, t);
 242                 return 1;
 243         }
 244
 245         if (right_nritems < push_items)
 246                 push_items = right_nritems;
 247         memcpy(left->keys + left_nritems, right->keys,
 248                 push_items * sizeof(struct key));
 249         memcpy(left->blockptrs + left_nritems, right->blockptrs,
 250                 push_items * sizeof(u64));
 251         memmove(right->keys, right->keys + push_items,
 252                 (right_nritems - push_items) * sizeof(struct key));
 253         memmove(right->blockptrs, right->blockptrs + push_items,
 254                 (right_nritems - push_items) * sizeof(u64));
 255         right->header.nritems -= push_items;
 256         left->header.nritems += push_items;
 257
 258         /* adjust the pointers going up the tree */
 259         fixup_low_keys(root, path, right->keys, level + 1);
 260
 261         write_tree_block(root, t);
 262         write_tree_block(root, right_buf);
 263
 264         /* then fixup the leaf pointer in the path */
 265         if (path->slots[level] < push_items) {
 266                 path->slots[level] += left_nritems;
 267                 tree_block_release(root, path->nodes[level]);
 268                 path->nodes[level] = t;
 269                 path->slots[level + 1] -= 1;
 270         } else {
 271                 path->slots[level] -= push_items;
 272                 tree_block_release(root, t);
 273         }
 274         return 0;
 275 }
 276
 277 /*
 278  * try to push data from one node into the next node right in the
 279  * tree.  The src node is found at specified level in the path.
 280  * If some bytes were pushed, return 0, otherwise return 1.
 281  *
 282  * Lower nodes/leaves in the path are not touched, higher nodes may
 283  * be modified to reflect the push.
 284  *
 285  * The path is altered to reflect the push.
 286  */
 287 int push_node_right(struct ctree_root *root, struct ctree_path *path, int level)
 288 {
 289         int slot;
 290         struct tree_buffer *t;
 291         struct tree_buffer *src_buffer;
 292         struct node *dst;
 293         struct node *src;
 294         int push_items = 0;
 295         int dst_nritems;
 296         int src_nritems;
 297
 298         /* can't push from the root */
 299         if (level == MAX_LEVEL - 1 || path->nodes[level + 1] == 0)
 300                 return 1;
 301
 302         /* only try to push inside the node higher up */
 303         slot = path->slots[level + 1];
 304         if (slot == NODEPTRS_PER_BLOCK - 1)
 305                 return 1;
 306
 307         if (slot >= path->nodes[level + 1]->node.header.nritems -1)
 308                 return 1;
 309
 310         t = read_tree_block(root,
 311                             path->nodes[level + 1]->node.blockptrs[slot + 1]);
 312         dst = &t->node;
 313         src_buffer = path->nodes[level];
 314         src = &src_buffer->node;
 315         dst_nritems = dst->header.nritems;
 316         src_nritems = src->header.nritems;
 317         push_items = NODEPTRS_PER_BLOCK - (dst_nritems + 1);
 318         if (push_items <= 0) {
 319                 tree_block_release(root, t);
 320                 return 1;
 321         }
 322
 323         if (src_nritems < push_items)
 324                 push_items = src_nritems;
 325         memmove(dst->keys + push_items, dst->keys,
 326                 dst_nritems * sizeof(struct key));
 327         memcpy(dst->keys, src->keys + src_nritems - push_items,
 328                 push_items * sizeof(struct key));
 329
 330         memmove(dst->blockptrs + push_items, dst->blockptrs,
 331                 dst_nritems * sizeof(u64));
 332         memcpy(dst->blockptrs, src->blockptrs + src_nritems - push_items,
 333                 push_items * sizeof(u64));
 334
 335         src->header.nritems -= push_items;
 336         dst->header.nritems += push_items;
 337
 338         /* adjust the pointers going up the tree */
 339         memcpy(path->nodes[level + 1]->node.keys + path->slots[level + 1] + 1,
 340                 dst->keys, sizeof(struct key));
 341
 342         write_tree_block(root, path->nodes[level + 1]);
 343         write_tree_block(root, t);
 344         write_tree_block(root, src_buffer);
 345
 346         /* then fixup the pointers in the path */
 347         if (path->slots[level] >= src->header.nritems) {
 348                 path->slots[level] -= src->header.nritems;
 349                 tree_block_release(root, path->nodes[level]);
 350                 path->nodes[level] = t;
 351                 path->slots[level + 1] += 1;
 352         } else {
 353                 tree_block_release(root, t);
 354         }
 355         return 0;
 356 }
 357
 358 static int insert_new_root(struct ctree_root *root, struct ctree_path *path, int level)
 359 {
 360         struct tree_buffer *t;
 361         struct node *lower;
 362         struct node *c;
 363         struct key *lower_key;
 364
 365         BUG_ON(path->nodes[level]);
 366         BUG_ON(path->nodes[level-1] != root->node);
 367
 368         t = alloc_free_block(root);
 369         c = &t->node;
 370         memset(c, 0, sizeof(c));
 371         c->header.nritems = 1;
 372         c->header.flags = node_level(level);
 373         c->header.blocknr = t->blocknr;
 374         c->header.parentid = root->node->node.header.parentid;
 375         lower = &path->nodes[level-1]->node;
 376         if (is_leaf(lower->header.flags))
 377                 lower_key = &((struct leaf *)lower)->items[0].key;
 378         else
 379                 lower_key = lower->keys;
 380         memcpy(c->keys, lower_key, sizeof(struct key));
 381         c->blockptrs[0] = path->nodes[level-1]->blocknr;
 382         /* the super has an extra ref to root->node */
 383         tree_block_release(root, root->node);
 384         root->node = t;
 385         t->count++;
 386         write_tree_block(root, t);
 387         path->nodes[level] = t;
 388         path->slots[level] = 0;
 389         return 0;
 390 }
 391
 392 /*
 393  * worker function to insert a single pointer in a node.
 394  * the node should have enough room for the pointer already
 395  * slot and level indicate where you want the key to go, and
 396  * blocknr is the block the key points to.
 397  */
 398 int insert_ptr(struct ctree_root *root,
 399                 struct ctree_path *path, struct key *key,
 400                 u64 blocknr, int slot, int level)
 401 {
 402         struct node *lower;
 403         int nritems;
 404
 405         BUG_ON(!path->nodes[level]);
 406         lower = &path->nodes[level]->node;
 407         nritems = lower->header.nritems;
 408         if (slot > nritems)
 409                 BUG();
 410         if (nritems == NODEPTRS_PER_BLOCK)
 411                 BUG();
 412         if (slot != nritems) {
 413                 memmove(lower->keys + slot + 1, lower->keys + slot,
 414                         (nritems - slot) * sizeof(struct key));
 415                 memmove(lower->blockptrs + slot + 1, lower->blockptrs + slot,
 416                         (nritems - slot) * sizeof(u64));
 417         }
 418         memcpy(lower->keys + slot, key, sizeof(struct key));
 419         lower->blockptrs[slot] = blocknr;
 420         lower->header.nritems++;
 421         if (lower->keys[1].objectid == 0)
 422                         BUG();
 423         write_tree_block(root, path->nodes[level]);
 424         return 0;
 425 }
 426
 427 int split_node(struct ctree_root *root, struct ctree_path *path, int level)
 428 {
 429         struct tree_buffer *t;
 430         struct node *c;
 431         struct tree_buffer *split_buffer;
 432         struct node *split;
 433         int mid;
 434         int ret;
 435
 436         ret = push_node_left(root, path, level);
 437         if (!ret)
 438                 return 0;
 439         ret = push_node_right(root, path, level);
 440         if (!ret)
 441                 return 0;
 442         t = path->nodes[level];
 443         c = &t->node;
 444         if (t == root->node) {
 445                 /* trying to split the root, lets make a new one */
 446                 ret = insert_new_root(root, path, level + 1);
 447                 if (ret)
 448                         return ret;
 449         }
 450         split_buffer = alloc_free_block(root);
 451         split = &split_buffer->node;
 452         split->header.flags = c->header.flags;
 453         split->header.blocknr = split_buffer->blocknr;
 454         split->header.parentid = root->node->node.header.parentid;
 455         mid = (c->header.nritems + 1) / 2;
 456         memcpy(split->keys, c->keys + mid,
 457                 (c->header.nritems - mid) * sizeof(struct key));
 458         memcpy(split->blockptrs, c->blockptrs + mid,
 459                 (c->header.nritems - mid) * sizeof(u64));
 460         split->header.nritems = c->header.nritems - mid;
 461         c->header.nritems = mid;
 462         write_tree_block(root, t);
 463         write_tree_block(root, split_buffer);
 464         insert_ptr(root, path, split->keys, split_buffer->blocknr,
 465                      path->slots[level + 1] + 1, level + 1);
 466         if (path->slots[level] > mid) {
 467                 path->slots[level] -= mid;
 468                 tree_block_release(root, t);
 469                 path->nodes[level] = split_buffer;
 470                 path->slots[level + 1] += 1;
 471         } else {
 472                 tree_block_release(root, split_buffer);
 473         }
 474         return 0;
 475 }
 476
 477 /*
 478  * how many bytes are required to store the items in a leaf.  start
 479  * and nr indicate which items in the leaf to check.  This totals up the
 480  * space used both by the item structs and the item data
 481  */
 482 int leaf_space_used(struct leaf *l, int start, int nr)
 483 {
 484         int data_len;
 485         int end = start + nr - 1;
 486
 487         if (!nr)
 488                 return 0;
 489         data_len = l->items[start].offset + l->items[start].size;
 490         data_len = data_len - l->items[end].offset;
 491         data_len += sizeof(struct item) * nr;
 492         return data_len;
 493 }
 494
 495 /*
 496  * push some data in the path leaf to the left, trying to free up at
 497  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
 498  */
 499 int push_leaf_left(struct ctree_root *root, struct ctree_path *path,
 500                    int data_size)
 501 {
 502         struct tree_buffer *right_buf = path->nodes[0];
 503         struct leaf *right = &right_buf->leaf;
 504         struct tree_buffer *t;
 505         struct leaf *left;
 506         int slot;
 507         int i;
 508         int free_space;
 509         int push_space = 0;
 510         int push_items = 0;
 511         struct item *item;
 512         int old_left_nritems;
 513
 514         slot = path->slots[1];
 515         if (slot == 0) {
 516                 return 1;
 517         }
 518         if (!path->nodes[1]) {
 519                 return 1;
 520         }
 521         t = read_tree_block(root, path->nodes[1]->node.blockptrs[slot - 1]);
 522         left = &t->leaf;
 523         free_space = leaf_free_space(left);
 524         if (free_space < data_size + sizeof(struct item)) {
 525                 tree_block_release(root, t);
 526                 return 1;
 527         }
 528         for (i = 0; i < right->header.nritems; i++) {
 529                 item = right->items + i;
 530                 if (path->slots[0] == i)
 531                         push_space += data_size + sizeof(*item);
 532                 if (item->size + sizeof(*item) + push_space > free_space)
 533                         break;
 534                 push_items++;
 535                 push_space += item->size + sizeof(*item);
 536         }
 537         if (push_items == 0) {
 538                 tree_block_release(root, t);
 539                 return 1;
 540         }
 541         /* push data from right to left */
 542         memcpy(left->items + left->header.nritems,
 543                 right->items, push_items * sizeof(struct item));
 544         push_space = LEAF_DATA_SIZE - right->items[push_items -1].offset;
 545         memcpy(left->data + leaf_data_end(left) - push_space,
 546                 right->data + right->items[push_items - 1].offset,
 547                 push_space);
 548         old_left_nritems = left->header.nritems;
 549         BUG_ON(old_left_nritems < 0);
 550
 551         for(i = old_left_nritems; i < old_left_nritems + push_items; i++) {
 552                 left->items[i].offset -= LEAF_DATA_SIZE -
 553                         left->items[old_left_nritems -1].offset;
 554         }
 555         left->header.nritems += push_items;
 556
 557         /* fixup right node */
 558         push_space = right->items[push_items-1].offset - leaf_data_end(right);
 559         memmove(right->data + LEAF_DATA_SIZE - push_space, right->data +
 560                 leaf_data_end(right), push_space);
 561         memmove(right->items, right->items + push_items,
 562                 (right->header.nritems - push_items) * sizeof(struct item));
 563         right->header.nritems -= push_items;
 564         push_space = LEAF_DATA_SIZE;
 565
 566         for (i = 0; i < right->header.nritems; i++) {
 567                 right->items[i].offset = push_space - right->items[i].size;
 568                 push_space = right->items[i].offset;
 569         }
 570
 571         write_tree_block(root, t);
 572         write_tree_block(root, right_buf);
 573
 574         fixup_low_keys(root, path, &right->items[0].key, 1);
 575
 576         /* then fixup the leaf pointer in the path */
 577         if (path->slots[0] < push_items) {
 578                 path->slots[0] += old_left_nritems;
 579                 tree_block_release(root, path->nodes[0]);
 580                 path->nodes[0] = t;
 581                 path->slots[1] -= 1;
 582         } else {
 583                 tree_block_release(root, t);
 584                 path->slots[0] -= push_items;
 585         }
 586         BUG_ON(path->slots[0] < 0);
 587         return 0;
 588 }
 589
 590 /*
 591  * split the path's leaf in two, making sure there is at least data_size
 592  * available for the resulting leaf level of the path.
 593  */
 594 int split_leaf(struct ctree_root *root, struct ctree_path *path, int data_size)
 595 {
 596         struct tree_buffer *l_buf = path->nodes[0];
 597         struct leaf *l = &l_buf->leaf;
 598         int nritems;
 599         int mid;
 600         int slot;
 601         struct leaf *right;
 602         struct tree_buffer *right_buffer;
 603         int space_needed = data_size + sizeof(struct item);
 604         int data_copy_size;
 605         int rt_data_off;
 606         int i;
 607         int ret;
 608
 609         if (push_leaf_left(root, path, data_size) == 0) {
 610                 l_buf = path->nodes[0];
 611                 l = &l_buf->leaf;
 612                 if (leaf_free_space(l) >= sizeof(struct item) + data_size)
 613                         return 0;
 614         }
 615         if (!path->nodes[1]) {
 616                 ret = insert_new_root(root, path, 1);
 617                 if (ret)
 618                         return ret;
 619         }
 620         slot = path->slots[0];
 621         nritems = l->header.nritems;
 622         mid = (nritems + 1)/ 2;
 623
 624         right_buffer = alloc_free_block(root);
 625         BUG_ON(!right_buffer);
 626         BUG_ON(mid == nritems);
 627         right = &right_buffer->leaf;
 628         memset(right, 0, sizeof(*right));
 629         if (mid <= slot) {
 630                 if (leaf_space_used(l, mid, nritems - mid) + space_needed >
 631                         LEAF_DATA_SIZE)
 632                         BUG();
 633         } else {
 634                 if (leaf_space_used(l, 0, mid + 1) + space_needed >
 635                         LEAF_DATA_SIZE)
 636                         BUG();
 637         }
 638         right->header.nritems = nritems - mid;
 639         right->header.blocknr = right_buffer->blocknr;
 640         right->header.flags = node_level(0);
 641         right->header.parentid = root->node->node.header.parentid;
 642         data_copy_size = l->items[mid].offset + l->items[mid].size -
 643                          leaf_data_end(l);
 644         memcpy(right->items, l->items + mid,
 645                (nritems - mid) * sizeof(struct item));
 646         memcpy(right->data + LEAF_DATA_SIZE - data_copy_size,
 647                l->data + leaf_data_end(l), data_copy_size);
 648         rt_data_off = LEAF_DATA_SIZE -
 649                      (l->items[mid].offset + l->items[mid].size);
 650
 651         for (i = 0; i < right->header.nritems; i++)
 652                 right->items[i].offset += rt_data_off;
 653
 654         l->header.nritems = mid;
 655         ret = insert_ptr(root, path, &right->items[0].key,
 656                           right_buffer->blocknr, path->slots[1] + 1, 1);
 657         write_tree_block(root, right_buffer);
 658         write_tree_block(root, l_buf);
 659
 660         BUG_ON(path->slots[0] != slot);
 661         if (mid <= slot) {
 662                 tree_block_release(root, path->nodes[0]);
 663                 path->nodes[0] = right_buffer;
 664                 path->slots[0] -= mid;
 665                 path->slots[1] += 1;
 666         } else
 667                 tree_block_release(root, right_buffer);
 668         BUG_ON(path->slots[0] < 0);
 669         return ret;
 670 }
 671
 672 /*
 673  * Given a key and some data, insert an item into the tree.
 674  * This does all the path init required, making room in the tree if needed.
 675  */
 676 int insert_item(struct ctree_root *root, struct key *key,
 677                           void *data, int data_size)
 678 {
 679         int ret;
 680         int slot;
 681         int slot_orig;
 682         struct leaf *leaf;
 683         struct tree_buffer *leaf_buf;
 684         unsigned int nritems;
 685         unsigned int data_end;
 686         struct ctree_path path;
 687
 688         /* create a root if there isn't one */
 689         if (!root->node)
 690                 BUG();
 691         init_path(&path);
 692         ret = search_slot(root, key, &path, data_size);
 693         if (ret == 0) {
 694                 release_path(root, &path);
 695                 return -EEXIST;
 696         }
 697
 698         slot_orig = path.slots[0];
 699         leaf_buf = path.nodes[0];
 700         leaf = &leaf_buf->leaf;
 701
 702         nritems = leaf->header.nritems;
 703         data_end = leaf_data_end(leaf);
 704
 705         if (leaf_free_space(leaf) <  sizeof(struct item) + data_size)
 706                 BUG();
 707
 708         slot = path.slots[0];
 709         BUG_ON(slot < 0);
 710         if (slot == 0)
 711                 fixup_low_keys(root, &path, key, 1);
 712         if (slot != nritems) {
 713                 int i;
 714                 unsigned int old_data = leaf->items[slot].offset +
 715                                         leaf->items[slot].size;
 716
 717                 /*
 718                  * item0..itemN ... dataN.offset..dataN.size .. data0.size
 719                  */
 720                 /* first correct the data pointers */
 721                 for (i = slot; i < nritems; i++)
 722                         leaf->items[i].offset -= data_size;
 723
 724                 /* shift the items */
 725                 memmove(leaf->items + slot + 1, leaf->items + slot,
 726                         (nritems - slot) * sizeof(struct item));
 727
 728                 /* shift the data */
 729                 memmove(leaf->data + data_end - data_size, leaf->data +
 730                         data_end, old_data - data_end);
 731                 data_end = old_data;
 732         }
 733         /* copy the new data in */
 734         memcpy(&leaf->items[slot].key, key, sizeof(struct key));
 735         leaf->items[slot].offset = data_end - data_size;
 736         leaf->items[slot].size = data_size;
 737         memcpy(leaf->data + data_end - data_size, data, data_size);
 738         leaf->header.nritems += 1;
 739         write_tree_block(root, leaf_buf);
 740         if (leaf_free_space(leaf) < 0)
 741                 BUG();
 742         release_path(root, &path);
 743         return 0;
 744 }
 745
 746 /*
 747  * delete the pointer from a given level in the path.  The path is not
 748  * fixed up, so after calling this it is not valid at that level.
 749  *
 750  * If the delete empties a node, the node is removed from the tree,
 751  * continuing all the way the root if required.  The root is converted into
 752  * a leaf if all the nodes are emptied.
 753  */
 754 int del_ptr(struct ctree_root *root, struct ctree_path *path, int level)
 755 {
 756         int slot;
 757         struct tree_buffer *t;
 758         struct node *node;
 759         int nritems;
 760         u64 blocknr;
 761
 762         while(1) {
 763                 t = path->nodes[level];
 764                 if (!t)
 765                         break;
 766                 node = &t->node;
 767                 slot = path->slots[level];
 768                 nritems = node->header.nritems;
 769
 770                 if (slot != nritems -1) {
 771                         memmove(node->keys + slot, node->keys + slot + 1,
 772                                 sizeof(struct key) * (nritems - slot - 1));
 773                         memmove(node->blockptrs + slot,
 774                                 node->blockptrs + slot + 1,
 775                                 sizeof(u64) * (nritems - slot - 1));
 776                 }
 777                 node->header.nritems--;
 778                 write_tree_block(root, t);
 779                 blocknr = t->blocknr;
 780                 if (node->header.nritems != 0) {
 781                         int tslot;
 782                         if (slot == 0)
 783                                 fixup_low_keys(root, path, node->keys,
 784                                                level + 1);
 785                         tslot = path->slots[level+1];
 786                         t->count++;
 787                         push_node_left(root, path, level);
 788                         if (node->header.nritems) {
 789                                 push_node_right(root, path, level);
 790                         }
 791                         if (node->header.nritems) {
 792                                 tree_block_release(root, t);
 793                                 break;
 794                         }
 795                         tree_block_release(root, t);
 796                         path->slots[level+1] = tslot;
 797                 }
 798                 if (t == root->node) {
 799                         /* just turn the root into a leaf and break */
 800                         root->node->node.header.flags = node_level(0);
 801                         write_tree_block(root, t);
 802                         break;
 803                 }
 804                 level++;
 805                 free_extent(root, blocknr, 1);
 806                 if (!path->nodes[level])
 807                         BUG();
 808         }
 809         return 0;
 810 }
 811
 812 /*
 813  * delete the item at the leaf level in path.  If that empties
 814  * the leaf, remove it from the tree
 815  */
 816 int del_item(struct ctree_root *root, struct ctree_path *path)
 817 {
 818         int slot;
 819         struct leaf *leaf;
 820         struct tree_buffer *leaf_buf;
 821         int doff;
 822         int dsize;
 823
 824         leaf_buf = path->nodes[0];
 825         leaf = &leaf_buf->leaf;
 826         slot = path->slots[0];
 827         doff = leaf->items[slot].offset;
 828         dsize = leaf->items[slot].size;
 829
 830         if (slot != leaf->header.nritems - 1) {
 831                 int i;
 832                 int data_end = leaf_data_end(leaf);
 833                 memmove(leaf->data + data_end + dsize,
 834                         leaf->data + data_end,
 835                         doff - data_end);
 836                 for (i = slot + 1; i < leaf->header.nritems; i++)
 837                         leaf->items[i].offset += dsize;
 838                 memmove(leaf->items + slot, leaf->items + slot + 1,
 839                         sizeof(struct item) *
 840                         (leaf->header.nritems - slot - 1));
 841         }
 842         leaf->header.nritems -= 1;
 843         /* delete the leaf if we've emptied it */
 844         if (leaf->header.nritems == 0) {
 845                 if (leaf_buf == root->node) {
 846                         leaf->header.flags = node_level(0);
 847                         write_tree_block(root, leaf_buf);
 848                 } else {
 849                         del_ptr(root, path, 1);
 850                         free_extent(root, leaf_buf->blocknr, 1);
 851                 }
 852         } else {
 853                 if (slot == 0)
 854                         fixup_low_keys(root, path, &leaf->items[0].key, 1);
 855                 write_tree_block(root, leaf_buf);
 856                 /* delete the leaf if it is mostly empty */
 857                 if (leaf_space_used(leaf, 0, leaf->header.nritems) <
 858                     LEAF_DATA_SIZE / 4) {
 859                         /* push_leaf_left fixes the path.
 860                          * make sure the path still points to our leaf
 861                          * for possible call to del_ptr below
 862                          */
 863                         slot = path->slots[1];
 864                         leaf_buf->count++;
 865                         push_leaf_left(root, path, 1);
 866                         if (leaf->header.nritems == 0) {
 867                                 path->slots[1] = slot;
 868                                 del_ptr(root, path, 1);
 869                         }
 870                         tree_block_release(root, leaf_buf);
 871                 }
 872         }
 873         return 0;
 874 }
 875
 876 static int del_pending_extents(struct ctree_root *extent_root)
 877 {
 878         int ret;
 879         struct key key;
 880         struct tree_buffer *gang[4];
 881         int i;
 882         struct ctree_path path;
 883
 884         while(1) {
 885                 ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
 886                                                  (void **)gang, 0, ARRAY_SIZE(gang),
 887                                                  CTREE_EXTENT_PENDING);
 888                 if (!ret)
 889                         break;
 890                 for (i = 0; i < ret; i++) {
 891                         key.objectid = gang[i]->blocknr;
 892                         key.flags = 0;
 893                         key.offset = 1;
 894                         init_path(&path);
 895                         ret = search_slot(extent_root, &key, &path, 0);
 896                         if (ret) {
 897                                 BUG();
 898                                 // FIXME undo it and return sane
 899                                 return ret;
 900                         }
 901                         ret = del_item(extent_root, &path);
 902                         if (ret) {
 903                                 BUG();
 904                                 return ret;
 905                         }
 906                         release_path(extent_root, &path);
 907                         radix_tree_tag_clear(&extent_root->cache_radix, gang[i]->blocknr,
 908                                                 CTREE_EXTENT_PENDING);
 909                         tree_block_release(extent_root, gang[i]);
 910                 }
 911         }
 912         return 0;
 913 }
 914
 915 int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
 916 {
 917         struct ctree_path path;
 918         struct key key;
 919         struct ctree_root *extent_root = root->extent_root;
 920         struct tree_buffer *t;
 921         int pending_ret;
 922         int ret;
 923
 924         key.objectid = blocknr;
 925         key.flags = 0;
 926         key.offset = num_blocks;
 927         if (root == extent_root) {
 928                 t = read_tree_block(root, key.objectid);
 929                 radix_tree_tag_set(&root->cache_radix, key.objectid, CTREE_EXTENT_PENDING);
 930                 return 0;
 931         }
 932         init_path(&path);
 933         ret = search_slot(extent_root, &key, &path, 0);
 934         if (ret)
 935                 BUG();
 936         ret = del_item(extent_root, &path);
 937         release_path(extent_root, &path);
 938         pending_ret = del_pending_extents(root->extent_root);
 939         return ret ? ret : pending_ret;
 940 }
 941
 942 int next_leaf(struct ctree_root *root, struct ctree_path *path)
 943 {
 944         int slot;
 945         int level = 1;
 946         u64 blocknr;
 947         struct tree_buffer *c;
 948         struct tree_buffer *next = NULL;
 949
 950         while(level < MAX_LEVEL) {
 951                 if (!path->nodes[level])
 952                         return -1;
 953                 slot = path->slots[level] + 1;
 954                 c = path->nodes[level];
 955                 if (slot >= c->node.header.nritems) {
 956                         level++;
 957                         continue;
 958                 }
 959                 blocknr = c->node.blockptrs[slot];
 960                 if (next)
 961                         tree_block_release(root, next);
 962                 next = read_tree_block(root, blocknr);
 963                 break;
 964         }
 965         path->slots[level] = slot;
 966         while(1) {
 967                 level--;
 968                 c = path->nodes[level];
 969                 tree_block_release(root, c);
 970                 path->nodes[level] = next;
 971                 path->slots[level] = 0;
 972                 if (!level)
 973                         break;
 974                 next = read_tree_block(root, next->node.blockptrs[0]);
 975         }
 976         return 0;
 977 }
 978
 979 int find_free_extent(struct ctree_root *orig_root, u64 num_blocks, u64 search_start,
 980                          u64 search_end, struct key *ins)
 981 {
 982         struct ctree_path path;
 983         struct key *key;
 984         int ret;
 985         u64 hole_size = 0;
 986         int slot = 0;
 987         u64 last_block;
 988         int start_found = 0;
 989         struct leaf *l;
 990         struct ctree_root * root = orig_root->extent_root;
 991
 992         init_path(&path);
 993         ins->objectid = search_start;
 994         ins->offset = 0;
 995         ins->flags = 0;
 996         ret = search_slot(root, ins, &path, 0);
 997         while (1) {
 998                 l = &path.nodes[0]->leaf;
 999                 slot = path.slots[0];
1000                 if (!l) {
1001                         // FIXME allocate root
1002                 }
1003                 if (slot >= l->header.nritems) {
1004                         ret = next_leaf(root, &path);
1005                         if (ret == 0)
1006                                 continue;
1007                         if (!start_found) {
1008                                 ins->objectid = search_start;
1009                                 ins->offset = num_blocks;
1010                                 hole_size = search_end - search_start;
1011                                 start_found = 1;
1012                                 goto insert;
1013                         }
1014                         ins->objectid = last_block;
1015                         ins->offset = num_blocks;
1016                         hole_size = search_end - last_block;
1017                         goto insert;
1018                 }
1019                 key = &l->items[slot].key;
1020                 if (start_found) {
1021                         hole_size = key->objectid - last_block;
1022                         if (hole_size > num_blocks) {
1023                                 ins->objectid = last_block;
1024                                 ins->offset = num_blocks;
1025                                 goto insert;
1026                         }
1027                 } else
1028                         start_found = 1;
1029                 last_block = key->objectid + key->offset;
1030 insert_failed:
1031                 path.slots[0]++;
1032         }
1033         // FIXME -ENOSPC
1034 insert:
1035         if (orig_root->extent_root == orig_root) {
1036                 BUG_ON(num_blocks != 1);
1037                 if ((root->current_insert.objectid <= ins->objectid &&
1038                     root->current_insert.objectid + root->current_insert.offset >
1039                     ins->objectid) ||
1040                    (root->current_insert.objectid > ins->objectid &&
1041                     root->current_insert.objectid <= ins->objectid + ins->offset) ||
1042                    radix_tree_tag_get(&root->cache_radix, ins->objectid,
1043                                       CTREE_EXTENT_PENDING)) {
1044                         last_block = ins->objectid + 1;
1045                         search_start = last_block;
1046                         goto insert_failed;
1047                 }
1048         }
1049         release_path(root, &path);
1050         if (ins->offset != 1)
1051                 BUG();
1052         return 0;
1053 }
1054
1055 static int insert_pending_extents(struct ctree_root *extent_root)
1056 {
1057         int ret;
1058         struct key key;
1059         struct extent_item item;
1060         struct tree_buffer *gang[4];
1061         int i;
1062
1063         // FIXME -ENOSPC
1064         item.refs = 1;
1065         item.owner = extent_root->node->node.header.parentid;
1066         while(1) {
1067                 ret = radix_tree_gang_lookup_tag(&extent_root->cache_radix,
1068                                                  (void **)gang, 0, ARRAY_SIZE(gang),
1069                                                  CTREE_EXTENT_PENDING);
1070                 if (!ret)
1071                         break;
1072                 for (i = 0; i < ret; i++) {
1073                         key.objectid = gang[i]->blocknr;
1074                         key.flags = 0;
1075                         key.offset = 1;
1076                         ret = insert_item(extent_root, &key, &item, sizeof(item));
1077                         if (ret) {
1078                                 BUG();
1079                                 // FIXME undo it and return sane
1080                                 return ret;
1081                         }
1082                         radix_tree_tag_clear(&extent_root->cache_radix, gang[i]->blocknr,
1083                                                 CTREE_EXTENT_PENDING);
1084                         tree_block_release(extent_root, gang[i]);
1085                 }
1086         }
1087         return 0;
1088 }
1089
1090 int alloc_extent(struct ctree_root *root, u64 num_blocks, u64 search_start,
1091                          u64 search_end, u64 owner, struct key *ins, struct tree_buffer **buf)
1092 {
1093         int ret;
1094         int pending_ret;
1095         struct extent_item extent_item;
1096
1097         extent_item.refs = 1;
1098         extent_item.owner = owner;
1099
1100         ret = find_free_extent(root, num_blocks, search_start, search_end, ins);
1101         if (ret)
1102                 return ret;
1103
1104         if (root != root->extent_root) {
1105                 memcpy(&root->extent_root->current_insert, ins, sizeof(*ins));
1106                 ret = insert_item(root->extent_root, ins, &extent_item, sizeof(extent_item));
1107                 memset(&root->extent_root->current_insert, 0, sizeof(struct key));
1108                 pending_ret = insert_pending_extents(root->extent_root);
1109                 if (ret)
1110                         return ret;
1111                 if (pending_ret)
1112                         return pending_ret;
1113                 *buf = find_tree_block(root, ins->objectid);
1114                 return 0;
1115         }
1116         /* we're allocating an extent for the extent tree, don't recurse */
1117         BUG_ON(ins->offset != 1);
1118         *buf = find_tree_block(root, ins->objectid);
1119         BUG_ON(!*buf);
1120         radix_tree_tag_set(&root->cache_radix, ins->objectid, CTREE_EXTENT_PENDING);
1121         (*buf)->count++;
1122         return 0;
1123
1124 }
1125
1126 struct tree_buffer *alloc_free_block(struct ctree_root *root)
1127 {
1128         struct key ins;
1129         int ret;
1130         struct tree_buffer *buf = NULL;
1131
1132         ret = alloc_extent(root, 1, 0, (unsigned long)-1, root->node->node.header.parentid,
1133                            &ins, &buf);
1134
1135         if (ret) {
1136                 BUG();
1137                 return NULL;
1138         }
1139         if (root != root->extent_root)
1140                 BUG_ON(radix_tree_tag_get(&root->extent_root->cache_radix, buf->blocknr,
1141                                           CTREE_EXTENT_PENDING));
1142         return buf;
1143 }
1144
1145 void print_leaf(struct leaf *l)
1146 {
1147         int i;
1148         int nr = l->header.nritems;
1149         struct item *item;
1150         struct extent_item *ei;
1151         printf("leaf %lu total ptrs %d free space %d\n", l->header.blocknr, nr,
1152                leaf_free_space(l));
1153         fflush(stdout);
1154         for (i = 0 ; i < nr ; i++) {
1155                 item = l->items + i;
1156                 printf("\titem %d key (%lu %u %lu) itemoff %d itemsize %d\n",
1157                         i,
1158                         item->key.objectid, item->key.flags, item->key.offset,
1159                         item->offset, item->size);
1160                 fflush(stdout);
1161                 printf("\t\titem data %.*s\n", item->size, l->data+item->offset);
1162                 ei = (struct extent_item *)(l->data + item->offset);
1163                 printf("\t\textent data %u %lu\n", ei->refs, ei->owner);
1164                 fflush(stdout);
1165         }
1166 }
1167 void print_tree(struct ctree_root *root, struct tree_buffer *t)
1168 {
1169         int i;
1170         int nr;
1171         struct node *c;
1172
1173         if (!t)
1174                 return;
1175         c = &t->node;
1176         nr = c->header.nritems;
1177         if (c->header.blocknr != t->blocknr)
1178                 BUG();
1179         if (is_leaf(c->header.flags)) {
1180                 print_leaf((struct leaf *)c);
1181                 return;
1182         }
1183         printf("node %lu level %d total ptrs %d free spc %lu\n", t->blocknr,
1184                 node_level(c->header.flags), c->header.nritems,
1185                 NODEPTRS_PER_BLOCK - c->header.nritems);
1186         fflush(stdout);
1187         for (i = 0; i < nr; i++) {
1188                 printf("\tkey %d (%lu %u %lu) block %lu\n",
1189                        i,
1190                        c->keys[i].objectid, c->keys[i].flags, c->keys[i].offset,
1191                        c->blockptrs[i]);
1192                 fflush(stdout);
1193         }
1194         for (i = 0; i < nr; i++) {
1195                 struct tree_buffer *next_buf = read_tree_block(root,
1196                                                             c->blockptrs[i]);
1197                 struct node *next = &next_buf->node;
1198                 if (is_leaf(next->header.flags) &&
1199                     node_level(c->header.flags) != 1)
1200                         BUG();
1201                 if (node_level(next->header.flags) !=
1202                         node_level(c->header.flags) - 1)
1203                         BUG();
1204                 print_tree(root, next_buf);
1205                 tree_block_release(root, next_buf);
1206         }
1207
1208 }
1209
1210 /* for testing only */
1211 int next_key(int i, int max_key) {
1212         // return rand() % max_key;
1213         return i;
1214 }
1215
1216 int main() {
1217         struct ctree_root *root;
1218         struct key ins;
1219         struct key last = { (u64)-1, 0, 0};
1220         char *buf;
1221         int i;
1222         int num;
1223         int ret;
1224         int run_size = 10000;
1225         int max_key = 100000000;
1226         int tree_size = 0;
1227         struct ctree_path path;
1228         struct ctree_super_block super;
1229
1230         radix_tree_init();
1231
1232
1233         root = open_ctree("dbfile", &super);
1234         printf("root tree\n");
1235         print_tree(root, root->node);
1236         printf("map tree\n");
1237         print_tree(root->extent_root, root->extent_root->node);
1238         fflush(stdout);
1239
1240         srand(55);
1241         for (i = 0; i < run_size; i++) {
1242                 buf = malloc(64);
1243                 num = next_key(i, max_key);
1244                 // num = i;
1245                 sprintf(buf, "string-%d", num);
1246                 // printf("insert %d\n", num);
1247                 ins.objectid = num;
1248                 ins.offset = 0;
1249                 ins.flags = 0;
1250                 ret = insert_item(root, &ins, buf, strlen(buf));
1251                 if (!ret)
1252                         tree_size++;
1253         }
1254         write_ctree_super(root, &super);
1255         close_ctree(root);
1256
1257         root = open_ctree("dbfile", &super);
1258         printf("starting search\n");
1259         srand(55);
1260         for (i = 0; i < run_size; i++) {
1261                 num = next_key(i, max_key);
1262                 ins.objectid = num;
1263                 init_path(&path);
1264                 ret = search_slot(root, &ins, &path, 0);
1265                 if (ret) {
1266                         print_tree(root, root->node);
1267                         printf("unable to find %d\n", num);
1268                         exit(1);
1269                 }
1270                 release_path(root, &path);
1271         }
1272         write_ctree_super(root, &super);
1273         close_ctree(root);
1274         root = open_ctree("dbfile", &super);
1275         printf("node %p level %d total ptrs %d free spc %lu\n", root->node,
1276                 node_level(root->node->node.header.flags),
1277                 root->node->node.header.nritems,
1278                 NODEPTRS_PER_BLOCK - root->node->node.header.nritems);
1279         printf("all searches good, deleting some items\n");
1280         i = 0;
1281         srand(55);
1282         for (i = 0 ; i < run_size/4; i++) {
1283                 num = next_key(i, max_key);
1284                 ins.objectid = num;
1285                 init_path(&path);
1286                 ret = search_slot(root, &ins, &path, 0);
1287                 if (ret)
1288                         continue;
1289                 ret = del_item(root, &path);
1290                 if (ret != 0)
1291                         BUG();
1292                 release_path(root, &path);
1293                 tree_size--;
1294         }
1295         srand(128);
1296         for (i = 0; i < run_size; i++) {
1297                 buf = malloc(64);
1298                 num = next_key(i, max_key);
1299                 sprintf(buf, "string-%d", num);
1300                 ins.objectid = num;
1301                 ret = insert_item(root, &ins, buf, strlen(buf));
1302                 if (!ret)
1303                         tree_size++;
1304                 if (i >= 5) {
1305                         struct key ugh;
1306                         ugh.objectid = 5;
1307                         ugh.flags = 0;
1308                         ugh.offset = 0;
1309                         init_path(&path);
1310                         ret = search_slot(root, &ugh, &path, 0);
1311                         if (ret) {
1312                                 print_tree(root, root->node);
1313                                 printf("unable to find 5 %d\n", num);
1314                                 exit(1);
1315                         }
1316                         release_path(root, &path);
1317
1318                 }
1319         }
1320         write_ctree_super(root, &super);
1321         close_ctree(root);
1322         root = open_ctree("dbfile", &super);
1323         srand(128);
1324         printf("starting search2\n");
1325         for (i = 0; i < run_size; i++) {
1326                 num = next_key(i, max_key);
1327                 ins.objectid = num;
1328                 init_path(&path);
1329                 ret = search_slot(root, &ins, &path, 0);
1330                 if (ret) {
1331                         print_tree(root, root->node);
1332                         printf("unable to find %d\n", num);
1333                         exit(1);
1334                 }
1335                 release_path(root, &path);
1336         }
1337         printf("starting big long delete run\n");
1338         while(root->node && root->node->node.header.nritems > 0) {
1339                 struct leaf *leaf;
1340                 int slot;
1341                 ins.objectid = (u64)-1;
1342                 init_path(&path);
1343                 ret = search_slot(root, &ins, &path, 0);
1344                 if (ret == 0)
1345                         BUG();
1346
1347                 leaf = &path.nodes[0]->leaf;
1348                 slot = path.slots[0];
1349                 if (slot != leaf->header.nritems)
1350                         BUG();
1351                 while(path.slots[0] > 0) {
1352                         path.slots[0] -= 1;
1353                         slot = path.slots[0];
1354                         leaf = &path.nodes[0]->leaf;
1355
1356                         if (comp_keys(&last, &leaf->items[slot].key) <= 0)
1357                                 BUG();
1358                         memcpy(&last, &leaf->items[slot].key, sizeof(last));
1359                         ret = del_item(root, &path);
1360                         if (ret != 0) {
1361                                 printf("del_item returned %d\n", ret);
1362                                 BUG();
1363                         }
1364                         tree_size--;
1365                 }
1366                 release_path(root, &path);
1367         }
1368         write_ctree_super(root, &super);
1369         close_ctree(root);
1370         printf("tree size is now %d\n", tree_size);
1371         printf("map tree\n");
1372         print_tree(root->extent_root, root->extent_root->node);
1373         return 0;
1374 }