1 /* 2 * linux/fs/hfs/brec.c 3 * 4 * Copyright (C) 2001 5 * Brad Boyer (flar@allandria.com) 6 * (C) 2003 Ardis Technologies <roman@ardistech.com> 7 * 8 * Handle individual btree records 9 */ 10 11 #include "btree.h" 12 13 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd); 14 static int hfs_brec_update_parent(struct hfs_find_data *fd); 15 static int hfs_btree_inc_height(struct hfs_btree *tree); 16 17 /* Get the length and offset of the given record in the given node */ 18 u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off) 19 { 20 __be16 retval[2]; 21 u16 dataoff; 22 23 dataoff = node->tree->node_size - (rec + 2) * 2; 24 hfs_bnode_read(node, retval, dataoff, 4); 25 *off = be16_to_cpu(retval[1]); 26 return be16_to_cpu(retval[0]) - *off; 27 } 28 29 /* Get the length of the key from a keyed record */ 30 u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec) 31 { 32 u16 retval, recoff; 33 34 if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF) 35 return 0; 36 37 if ((node->type == HFS_NODE_INDEX) && 38 !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) { 39 if (node->tree->attributes & HFS_TREE_BIGKEYS) 40 retval = node->tree->max_key_len + 2; 41 else 42 retval = node->tree->max_key_len + 1; 43 } else { 44 recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2); 45 if (!recoff) 46 return 0; 47 if (node->tree->attributes & HFS_TREE_BIGKEYS) { 48 retval = hfs_bnode_read_u16(node, recoff) + 2; 49 if (retval > node->tree->max_key_len + 2) { 50 pr_err("keylen %d too large\n", retval); 51 retval = 0; 52 } 53 } else { 54 retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1; 55 if (retval > node->tree->max_key_len + 1) { 56 pr_err("keylen %d too large\n", retval); 57 retval = 0; 58 } 59 } 60 } 61 return retval; 62 } 63 64 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len) 65 { 66 struct hfs_btree *tree; 67 struct hfs_bnode *node, *new_node; 68 int size, key_len, rec; 69 int data_off, end_off; 70 int idx_rec_off, data_rec_off, end_rec_off; 71 __be32 cnid; 72 73 tree = fd->tree; 74 if (!fd->bnode) { 75 if (!tree->root) 76 hfs_btree_inc_height(tree); 77 fd->bnode = hfs_bnode_find(tree, tree->leaf_head); 78 if (IS_ERR(fd->bnode)) 79 return PTR_ERR(fd->bnode); 80 fd->record = -1; 81 } 82 new_node = NULL; 83 key_len = (fd->search_key->key_len | 1) + 1; 84 again: 85 /* new record idx and complete record size */ 86 rec = fd->record + 1; 87 size = key_len + entry_len; 88 89 node = fd->bnode; 90 hfs_bnode_dump(node); 91 /* get last offset */ 92 end_rec_off = tree->node_size - (node->num_recs + 1) * 2; 93 end_off = hfs_bnode_read_u16(node, end_rec_off); 94 end_rec_off -= 2; 95 hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", 96 rec, size, end_off, end_rec_off); 97 if (size > end_rec_off - end_off) { 98 if (new_node) 99 panic("not enough room!\n"); 100 new_node = hfs_bnode_split(fd); 101 if (IS_ERR(new_node)) 102 return PTR_ERR(new_node); 103 goto again; 104 } 105 if (node->type == HFS_NODE_LEAF) { 106 tree->leaf_count++; 107 mark_inode_dirty(tree->inode); 108 } 109 node->num_recs++; 110 /* write new last offset */ 111 hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs); 112 hfs_bnode_write_u16(node, end_rec_off, end_off + size); 113 data_off = end_off; 114 data_rec_off = end_rec_off + 2; 115 idx_rec_off = tree->node_size - (rec + 1) * 2; 116 if (idx_rec_off == data_rec_off) 117 goto skip; 118 /* move all following entries */ 119 do { 120 data_off = hfs_bnode_read_u16(node, data_rec_off + 2); 121 hfs_bnode_write_u16(node, data_rec_off, data_off + size); 122 data_rec_off += 2; 123 } while (data_rec_off < idx_rec_off); 124 125 /* move data away */ 126 hfs_bnode_move(node, data_off + size, data_off, 127 end_off - data_off); 128 129 skip: 130 hfs_bnode_write(node, fd->search_key, data_off, key_len); 131 hfs_bnode_write(node, entry, data_off + key_len, entry_len); 132 hfs_bnode_dump(node); 133 134 /* 135 * update parent key if we inserted a key 136 * at the start of the node and it is not the new node 137 */ 138 if (!rec && new_node != node) { 139 hfs_bnode_read_key(node, fd->search_key, data_off + size); 140 hfs_brec_update_parent(fd); 141 } 142 143 if (new_node) { 144 hfs_bnode_put(fd->bnode); 145 if (!new_node->parent) { 146 hfs_btree_inc_height(tree); 147 new_node->parent = tree->root; 148 } 149 fd->bnode = hfs_bnode_find(tree, new_node->parent); 150 151 /* create index data entry */ 152 cnid = cpu_to_be32(new_node->this); 153 entry = &cnid; 154 entry_len = sizeof(cnid); 155 156 /* get index key */ 157 hfs_bnode_read_key(new_node, fd->search_key, 14); 158 __hfs_brec_find(fd->bnode, fd); 159 160 hfs_bnode_put(new_node); 161 new_node = NULL; 162 163 if (tree->attributes & HFS_TREE_VARIDXKEYS) 164 key_len = fd->search_key->key_len + 1; 165 else { 166 fd->search_key->key_len = tree->max_key_len; 167 key_len = tree->max_key_len + 1; 168 } 169 goto again; 170 } 171 172 return 0; 173 } 174 175 int hfs_brec_remove(struct hfs_find_data *fd) 176 { 177 struct hfs_btree *tree; 178 struct hfs_bnode *node, *parent; 179 int end_off, rec_off, data_off, size; 180 181 tree = fd->tree; 182 node = fd->bnode; 183 again: 184 rec_off = tree->node_size - (fd->record + 2) * 2; 185 end_off = tree->node_size - (node->num_recs + 1) * 2; 186 187 if (node->type == HFS_NODE_LEAF) { 188 tree->leaf_count--; 189 mark_inode_dirty(tree->inode); 190 } 191 hfs_bnode_dump(node); 192 hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n", 193 fd->record, fd->keylength + fd->entrylength); 194 if (!--node->num_recs) { 195 hfs_bnode_unlink(node); 196 if (!node->parent) 197 return 0; 198 parent = hfs_bnode_find(tree, node->parent); 199 if (IS_ERR(parent)) 200 return PTR_ERR(parent); 201 hfs_bnode_put(node); 202 node = fd->bnode = parent; 203 204 __hfs_brec_find(node, fd); 205 goto again; 206 } 207 hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs); 208 209 if (rec_off == end_off) 210 goto skip; 211 size = fd->keylength + fd->entrylength; 212 213 do { 214 data_off = hfs_bnode_read_u16(node, rec_off); 215 hfs_bnode_write_u16(node, rec_off + 2, data_off - size); 216 rec_off -= 2; 217 } while (rec_off >= end_off); 218 219 /* fill hole */ 220 hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size, 221 data_off - fd->keyoffset - size); 222 skip: 223 hfs_bnode_dump(node); 224 if (!fd->record) 225 hfs_brec_update_parent(fd); 226 return 0; 227 } 228 229 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd) 230 { 231 struct hfs_btree *tree; 232 struct hfs_bnode *node, *new_node, *next_node; 233 struct hfs_bnode_desc node_desc; 234 int num_recs, new_rec_off, new_off, old_rec_off; 235 int data_start, data_end, size; 236 237 tree = fd->tree; 238 node = fd->bnode; 239 new_node = hfs_bmap_alloc(tree); 240 if (IS_ERR(new_node)) 241 return new_node; 242 hfs_bnode_get(node); 243 hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n", 244 node->this, new_node->this, node->next); 245 new_node->next = node->next; 246 new_node->prev = node->this; 247 new_node->parent = node->parent; 248 new_node->type = node->type; 249 new_node->height = node->height; 250 251 if (node->next) 252 next_node = hfs_bnode_find(tree, node->next); 253 else 254 next_node = NULL; 255 256 if (IS_ERR(next_node)) { 257 hfs_bnode_put(node); 258 hfs_bnode_put(new_node); 259 return next_node; 260 } 261 262 size = tree->node_size / 2 - node->num_recs * 2 - 14; 263 old_rec_off = tree->node_size - 4; 264 num_recs = 1; 265 for (;;) { 266 data_start = hfs_bnode_read_u16(node, old_rec_off); 267 if (data_start > size) 268 break; 269 old_rec_off -= 2; 270 if (++num_recs < node->num_recs) 271 continue; 272 /* panic? */ 273 hfs_bnode_put(node); 274 hfs_bnode_put(new_node); 275 if (next_node) 276 hfs_bnode_put(next_node); 277 return ERR_PTR(-ENOSPC); 278 } 279 280 if (fd->record + 1 < num_recs) { 281 /* new record is in the lower half, 282 * so leave some more space there 283 */ 284 old_rec_off += 2; 285 num_recs--; 286 data_start = hfs_bnode_read_u16(node, old_rec_off); 287 } else { 288 hfs_bnode_put(node); 289 hfs_bnode_get(new_node); 290 fd->bnode = new_node; 291 fd->record -= num_recs; 292 fd->keyoffset -= data_start - 14; 293 fd->entryoffset -= data_start - 14; 294 } 295 new_node->num_recs = node->num_recs - num_recs; 296 node->num_recs = num_recs; 297 298 new_rec_off = tree->node_size - 2; 299 new_off = 14; 300 size = data_start - new_off; 301 num_recs = new_node->num_recs; 302 data_end = data_start; 303 while (num_recs) { 304 hfs_bnode_write_u16(new_node, new_rec_off, new_off); 305 old_rec_off -= 2; 306 new_rec_off -= 2; 307 data_end = hfs_bnode_read_u16(node, old_rec_off); 308 new_off = data_end - size; 309 num_recs--; 310 } 311 hfs_bnode_write_u16(new_node, new_rec_off, new_off); 312 hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start); 313 314 /* update new bnode header */ 315 node_desc.next = cpu_to_be32(new_node->next); 316 node_desc.prev = cpu_to_be32(new_node->prev); 317 node_desc.type = new_node->type; 318 node_desc.height = new_node->height; 319 node_desc.num_recs = cpu_to_be16(new_node->num_recs); 320 node_desc.reserved = 0; 321 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc)); 322 323 /* update previous bnode header */ 324 node->next = new_node->this; 325 hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc)); 326 node_desc.next = cpu_to_be32(node->next); 327 node_desc.num_recs = cpu_to_be16(node->num_recs); 328 hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc)); 329 330 /* update next bnode header */ 331 if (next_node) { 332 next_node->prev = new_node->this; 333 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc)); 334 node_desc.prev = cpu_to_be32(next_node->prev); 335 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc)); 336 hfs_bnode_put(next_node); 337 } else if (node->this == tree->leaf_tail) { 338 /* if there is no next node, this might be the new tail */ 339 tree->leaf_tail = new_node->this; 340 mark_inode_dirty(tree->inode); 341 } 342 343 hfs_bnode_dump(node); 344 hfs_bnode_dump(new_node); 345 hfs_bnode_put(node); 346 347 return new_node; 348 } 349 350 static int hfs_brec_update_parent(struct hfs_find_data *fd) 351 { 352 struct hfs_btree *tree; 353 struct hfs_bnode *node, *new_node, *parent; 354 int newkeylen, diff; 355 int rec, rec_off, end_rec_off; 356 int start_off, end_off; 357 358 tree = fd->tree; 359 node = fd->bnode; 360 new_node = NULL; 361 if (!node->parent) 362 return 0; 363 364 again: 365 parent = hfs_bnode_find(tree, node->parent); 366 if (IS_ERR(parent)) 367 return PTR_ERR(parent); 368 __hfs_brec_find(parent, fd); 369 if (fd->record < 0) 370 return -ENOENT; 371 hfs_bnode_dump(parent); 372 rec = fd->record; 373 374 /* size difference between old and new key */ 375 if (tree->attributes & HFS_TREE_VARIDXKEYS) 376 newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1; 377 else 378 fd->keylength = newkeylen = tree->max_key_len + 1; 379 hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n", 380 rec, fd->keylength, newkeylen); 381 382 rec_off = tree->node_size - (rec + 2) * 2; 383 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2; 384 diff = newkeylen - fd->keylength; 385 if (!diff) 386 goto skip; 387 if (diff > 0) { 388 end_off = hfs_bnode_read_u16(parent, end_rec_off); 389 if (end_rec_off - end_off < diff) { 390 391 printk(KERN_DEBUG "splitting index node...\n"); 392 fd->bnode = parent; 393 new_node = hfs_bnode_split(fd); 394 if (IS_ERR(new_node)) 395 return PTR_ERR(new_node); 396 parent = fd->bnode; 397 rec = fd->record; 398 rec_off = tree->node_size - (rec + 2) * 2; 399 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2; 400 } 401 } 402 403 end_off = start_off = hfs_bnode_read_u16(parent, rec_off); 404 hfs_bnode_write_u16(parent, rec_off, start_off + diff); 405 start_off -= 4; /* move previous cnid too */ 406 407 while (rec_off > end_rec_off) { 408 rec_off -= 2; 409 end_off = hfs_bnode_read_u16(parent, rec_off); 410 hfs_bnode_write_u16(parent, rec_off, end_off + diff); 411 } 412 hfs_bnode_move(parent, start_off + diff, start_off, 413 end_off - start_off); 414 skip: 415 hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen); 416 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) 417 hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1); 418 hfs_bnode_dump(parent); 419 420 hfs_bnode_put(node); 421 node = parent; 422 423 if (new_node) { 424 __be32 cnid; 425 426 fd->bnode = hfs_bnode_find(tree, new_node->parent); 427 /* create index key and entry */ 428 hfs_bnode_read_key(new_node, fd->search_key, 14); 429 cnid = cpu_to_be32(new_node->this); 430 431 __hfs_brec_find(fd->bnode, fd); 432 hfs_brec_insert(fd, &cnid, sizeof(cnid)); 433 hfs_bnode_put(fd->bnode); 434 hfs_bnode_put(new_node); 435 436 if (!rec) { 437 if (new_node == node) 438 goto out; 439 /* restore search_key */ 440 hfs_bnode_read_key(node, fd->search_key, 14); 441 } 442 } 443 444 if (!rec && node->parent) 445 goto again; 446 out: 447 fd->bnode = node; 448 return 0; 449 } 450 451 static int hfs_btree_inc_height(struct hfs_btree *tree) 452 { 453 struct hfs_bnode *node, *new_node; 454 struct hfs_bnode_desc node_desc; 455 int key_size, rec; 456 __be32 cnid; 457 458 node = NULL; 459 if (tree->root) { 460 node = hfs_bnode_find(tree, tree->root); 461 if (IS_ERR(node)) 462 return PTR_ERR(node); 463 } 464 new_node = hfs_bmap_alloc(tree); 465 if (IS_ERR(new_node)) { 466 hfs_bnode_put(node); 467 return PTR_ERR(new_node); 468 } 469 470 tree->root = new_node->this; 471 if (!tree->depth) { 472 tree->leaf_head = tree->leaf_tail = new_node->this; 473 new_node->type = HFS_NODE_LEAF; 474 new_node->num_recs = 0; 475 } else { 476 new_node->type = HFS_NODE_INDEX; 477 new_node->num_recs = 1; 478 } 479 new_node->parent = 0; 480 new_node->next = 0; 481 new_node->prev = 0; 482 new_node->height = ++tree->depth; 483 484 node_desc.next = cpu_to_be32(new_node->next); 485 node_desc.prev = cpu_to_be32(new_node->prev); 486 node_desc.type = new_node->type; 487 node_desc.height = new_node->height; 488 node_desc.num_recs = cpu_to_be16(new_node->num_recs); 489 node_desc.reserved = 0; 490 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc)); 491 492 rec = tree->node_size - 2; 493 hfs_bnode_write_u16(new_node, rec, 14); 494 495 if (node) { 496 /* insert old root idx into new root */ 497 node->parent = tree->root; 498 if (node->type == HFS_NODE_LEAF || 499 tree->attributes & HFS_TREE_VARIDXKEYS) 500 key_size = hfs_bnode_read_u8(node, 14) + 1; 501 else 502 key_size = tree->max_key_len + 1; 503 hfs_bnode_copy(new_node, 14, node, 14, key_size); 504 505 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) { 506 key_size = tree->max_key_len + 1; 507 hfs_bnode_write_u8(new_node, 14, tree->max_key_len); 508 } 509 key_size = (key_size + 1) & -2; 510 cnid = cpu_to_be32(node->this); 511 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4); 512 513 rec -= 2; 514 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4); 515 516 hfs_bnode_put(node); 517 } 518 hfs_bnode_put(new_node); 519 mark_inode_dirty(tree->inode); 520 521 return 0; 522 } 523