1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/hfs/brec.c 4 * 5 * Copyright (C) 2001 6 * Brad Boyer (flar@allandria.com) 7 * (C) 2003 Ardis Technologies <roman@ardistech.com> 8 * 9 * Handle individual btree records 10 */ 11 12 #include "btree.h" 13 14 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd); 15 static int hfs_brec_update_parent(struct hfs_find_data *fd); 16 static int hfs_btree_inc_height(struct hfs_btree *tree); 17 18 /* Get the length and offset of the given record in the given node */ 19 u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off) 20 { 21 __be16 retval[2]; 22 u16 dataoff; 23 24 dataoff = node->tree->node_size - (rec + 2) * 2; 25 hfs_bnode_read(node, retval, dataoff, 4); 26 *off = be16_to_cpu(retval[1]); 27 return be16_to_cpu(retval[0]) - *off; 28 } 29 30 /* Get the length of the key from a keyed record */ 31 u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec) 32 { 33 u16 retval, recoff; 34 35 if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF) 36 return 0; 37 38 if ((node->type == HFS_NODE_INDEX) && 39 !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) { 40 if (node->tree->attributes & HFS_TREE_BIGKEYS) 41 retval = node->tree->max_key_len + 2; 42 else 43 retval = node->tree->max_key_len + 1; 44 } else { 45 recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2); 46 if (!recoff) 47 return 0; 48 if (node->tree->attributes & HFS_TREE_BIGKEYS) { 49 retval = hfs_bnode_read_u16(node, recoff) + 2; 50 if (retval > node->tree->max_key_len + 2) { 51 pr_err("keylen %d too large\n", retval); 52 retval = 0; 53 } 54 } else { 55 retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1; 56 if (retval > node->tree->max_key_len + 1) { 57 pr_err("keylen %d too large\n", retval); 58 retval = 0; 59 } 60 } 61 } 62 return retval; 63 } 64 65 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len) 66 { 67 struct hfs_btree *tree; 68 struct hfs_bnode *node, *new_node; 69 int size, key_len, rec; 70 int data_off, end_off; 71 int idx_rec_off, data_rec_off, end_rec_off; 72 __be32 cnid; 73 74 tree = fd->tree; 75 if (!fd->bnode) { 76 if (!tree->root) 77 hfs_btree_inc_height(tree); 78 fd->bnode = hfs_bnode_find(tree, tree->leaf_head); 79 if (IS_ERR(fd->bnode)) 80 return PTR_ERR(fd->bnode); 81 fd->record = -1; 82 } 83 new_node = NULL; 84 key_len = (fd->search_key->key_len | 1) + 1; 85 again: 86 /* new record idx and complete record size */ 87 rec = fd->record + 1; 88 size = key_len + entry_len; 89 90 node = fd->bnode; 91 hfs_bnode_dump(node); 92 /* get last offset */ 93 end_rec_off = tree->node_size - (node->num_recs + 1) * 2; 94 end_off = hfs_bnode_read_u16(node, end_rec_off); 95 end_rec_off -= 2; 96 hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", 97 rec, size, end_off, end_rec_off); 98 if (size > end_rec_off - end_off) { 99 if (new_node) 100 panic("not enough room!\n"); 101 new_node = hfs_bnode_split(fd); 102 if (IS_ERR(new_node)) 103 return PTR_ERR(new_node); 104 goto again; 105 } 106 if (node->type == HFS_NODE_LEAF) { 107 tree->leaf_count++; 108 mark_inode_dirty(tree->inode); 109 } 110 node->num_recs++; 111 /* write new last offset */ 112 hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs); 113 hfs_bnode_write_u16(node, end_rec_off, end_off + size); 114 data_off = end_off; 115 data_rec_off = end_rec_off + 2; 116 idx_rec_off = tree->node_size - (rec + 1) * 2; 117 if (idx_rec_off == data_rec_off) 118 goto skip; 119 /* move all following entries */ 120 do { 121 data_off = hfs_bnode_read_u16(node, data_rec_off + 2); 122 hfs_bnode_write_u16(node, data_rec_off, data_off + size); 123 data_rec_off += 2; 124 } while (data_rec_off < idx_rec_off); 125 126 /* move data away */ 127 hfs_bnode_move(node, data_off + size, data_off, 128 end_off - data_off); 129 130 skip: 131 hfs_bnode_write(node, fd->search_key, data_off, key_len); 132 hfs_bnode_write(node, entry, data_off + key_len, entry_len); 133 hfs_bnode_dump(node); 134 135 /* 136 * update parent key if we inserted a key 137 * at the start of the node and it is not the new node 138 */ 139 if (!rec && new_node != node) { 140 hfs_bnode_read_key(node, fd->search_key, data_off + size); 141 hfs_brec_update_parent(fd); 142 } 143 144 if (new_node) { 145 hfs_bnode_put(fd->bnode); 146 if (!new_node->parent) { 147 hfs_btree_inc_height(tree); 148 new_node->parent = tree->root; 149 } 150 fd->bnode = hfs_bnode_find(tree, new_node->parent); 151 152 /* create index data entry */ 153 cnid = cpu_to_be32(new_node->this); 154 entry = &cnid; 155 entry_len = sizeof(cnid); 156 157 /* get index key */ 158 hfs_bnode_read_key(new_node, fd->search_key, 14); 159 __hfs_brec_find(fd->bnode, fd); 160 161 hfs_bnode_put(new_node); 162 new_node = NULL; 163 164 if (tree->attributes & HFS_TREE_VARIDXKEYS) 165 key_len = fd->search_key->key_len + 1; 166 else { 167 fd->search_key->key_len = tree->max_key_len; 168 key_len = tree->max_key_len + 1; 169 } 170 goto again; 171 } 172 173 return 0; 174 } 175 176 int hfs_brec_remove(struct hfs_find_data *fd) 177 { 178 struct hfs_btree *tree; 179 struct hfs_bnode *node, *parent; 180 int end_off, rec_off, data_off, size; 181 182 tree = fd->tree; 183 node = fd->bnode; 184 again: 185 rec_off = tree->node_size - (fd->record + 2) * 2; 186 end_off = tree->node_size - (node->num_recs + 1) * 2; 187 188 if (node->type == HFS_NODE_LEAF) { 189 tree->leaf_count--; 190 mark_inode_dirty(tree->inode); 191 } 192 hfs_bnode_dump(node); 193 hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n", 194 fd->record, fd->keylength + fd->entrylength); 195 if (!--node->num_recs) { 196 hfs_bnode_unlink(node); 197 if (!node->parent) 198 return 0; 199 parent = hfs_bnode_find(tree, node->parent); 200 if (IS_ERR(parent)) 201 return PTR_ERR(parent); 202 hfs_bnode_put(node); 203 node = fd->bnode = parent; 204 205 __hfs_brec_find(node, fd); 206 goto again; 207 } 208 hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs); 209 210 if (rec_off == end_off) 211 goto skip; 212 size = fd->keylength + fd->entrylength; 213 214 do { 215 data_off = hfs_bnode_read_u16(node, rec_off); 216 hfs_bnode_write_u16(node, rec_off + 2, data_off - size); 217 rec_off -= 2; 218 } while (rec_off >= end_off); 219 220 /* fill hole */ 221 hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size, 222 data_off - fd->keyoffset - size); 223 skip: 224 hfs_bnode_dump(node); 225 if (!fd->record) 226 hfs_brec_update_parent(fd); 227 return 0; 228 } 229 230 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd) 231 { 232 struct hfs_btree *tree; 233 struct hfs_bnode *node, *new_node, *next_node; 234 struct hfs_bnode_desc node_desc; 235 int num_recs, new_rec_off, new_off, old_rec_off; 236 int data_start, data_end, size; 237 238 tree = fd->tree; 239 node = fd->bnode; 240 new_node = hfs_bmap_alloc(tree); 241 if (IS_ERR(new_node)) 242 return new_node; 243 hfs_bnode_get(node); 244 hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n", 245 node->this, new_node->this, node->next); 246 new_node->next = node->next; 247 new_node->prev = node->this; 248 new_node->parent = node->parent; 249 new_node->type = node->type; 250 new_node->height = node->height; 251 252 if (node->next) 253 next_node = hfs_bnode_find(tree, node->next); 254 else 255 next_node = NULL; 256 257 if (IS_ERR(next_node)) { 258 hfs_bnode_put(node); 259 hfs_bnode_put(new_node); 260 return next_node; 261 } 262 263 size = tree->node_size / 2 - node->num_recs * 2 - 14; 264 old_rec_off = tree->node_size - 4; 265 num_recs = 1; 266 for (;;) { 267 data_start = hfs_bnode_read_u16(node, old_rec_off); 268 if (data_start > size) 269 break; 270 old_rec_off -= 2; 271 if (++num_recs < node->num_recs) 272 continue; 273 /* panic? */ 274 hfs_bnode_put(node); 275 hfs_bnode_put(new_node); 276 if (next_node) 277 hfs_bnode_put(next_node); 278 return ERR_PTR(-ENOSPC); 279 } 280 281 if (fd->record + 1 < num_recs) { 282 /* new record is in the lower half, 283 * so leave some more space there 284 */ 285 old_rec_off += 2; 286 num_recs--; 287 data_start = hfs_bnode_read_u16(node, old_rec_off); 288 } else { 289 hfs_bnode_put(node); 290 hfs_bnode_get(new_node); 291 fd->bnode = new_node; 292 fd->record -= num_recs; 293 fd->keyoffset -= data_start - 14; 294 fd->entryoffset -= data_start - 14; 295 } 296 new_node->num_recs = node->num_recs - num_recs; 297 node->num_recs = num_recs; 298 299 new_rec_off = tree->node_size - 2; 300 new_off = 14; 301 size = data_start - new_off; 302 num_recs = new_node->num_recs; 303 data_end = data_start; 304 while (num_recs) { 305 hfs_bnode_write_u16(new_node, new_rec_off, new_off); 306 old_rec_off -= 2; 307 new_rec_off -= 2; 308 data_end = hfs_bnode_read_u16(node, old_rec_off); 309 new_off = data_end - size; 310 num_recs--; 311 } 312 hfs_bnode_write_u16(new_node, new_rec_off, new_off); 313 hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start); 314 315 /* update new bnode header */ 316 node_desc.next = cpu_to_be32(new_node->next); 317 node_desc.prev = cpu_to_be32(new_node->prev); 318 node_desc.type = new_node->type; 319 node_desc.height = new_node->height; 320 node_desc.num_recs = cpu_to_be16(new_node->num_recs); 321 node_desc.reserved = 0; 322 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc)); 323 324 /* update previous bnode header */ 325 node->next = new_node->this; 326 hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc)); 327 node_desc.next = cpu_to_be32(node->next); 328 node_desc.num_recs = cpu_to_be16(node->num_recs); 329 hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc)); 330 331 /* update next bnode header */ 332 if (next_node) { 333 next_node->prev = new_node->this; 334 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc)); 335 node_desc.prev = cpu_to_be32(next_node->prev); 336 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc)); 337 hfs_bnode_put(next_node); 338 } else if (node->this == tree->leaf_tail) { 339 /* if there is no next node, this might be the new tail */ 340 tree->leaf_tail = new_node->this; 341 mark_inode_dirty(tree->inode); 342 } 343 344 hfs_bnode_dump(node); 345 hfs_bnode_dump(new_node); 346 hfs_bnode_put(node); 347 348 return new_node; 349 } 350 351 static int hfs_brec_update_parent(struct hfs_find_data *fd) 352 { 353 struct hfs_btree *tree; 354 struct hfs_bnode *node, *new_node, *parent; 355 int newkeylen, diff; 356 int rec, rec_off, end_rec_off; 357 int start_off, end_off; 358 359 tree = fd->tree; 360 node = fd->bnode; 361 new_node = NULL; 362 if (!node->parent) 363 return 0; 364 365 again: 366 parent = hfs_bnode_find(tree, node->parent); 367 if (IS_ERR(parent)) 368 return PTR_ERR(parent); 369 __hfs_brec_find(parent, fd); 370 if (fd->record < 0) 371 return -ENOENT; 372 hfs_bnode_dump(parent); 373 rec = fd->record; 374 375 /* size difference between old and new key */ 376 if (tree->attributes & HFS_TREE_VARIDXKEYS) 377 newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1; 378 else 379 fd->keylength = newkeylen = tree->max_key_len + 1; 380 hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n", 381 rec, fd->keylength, newkeylen); 382 383 rec_off = tree->node_size - (rec + 2) * 2; 384 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2; 385 diff = newkeylen - fd->keylength; 386 if (!diff) 387 goto skip; 388 if (diff > 0) { 389 end_off = hfs_bnode_read_u16(parent, end_rec_off); 390 if (end_rec_off - end_off < diff) { 391 392 printk(KERN_DEBUG "splitting index node...\n"); 393 fd->bnode = parent; 394 new_node = hfs_bnode_split(fd); 395 if (IS_ERR(new_node)) 396 return PTR_ERR(new_node); 397 parent = fd->bnode; 398 rec = fd->record; 399 rec_off = tree->node_size - (rec + 2) * 2; 400 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2; 401 } 402 } 403 404 end_off = start_off = hfs_bnode_read_u16(parent, rec_off); 405 hfs_bnode_write_u16(parent, rec_off, start_off + diff); 406 start_off -= 4; /* move previous cnid too */ 407 408 while (rec_off > end_rec_off) { 409 rec_off -= 2; 410 end_off = hfs_bnode_read_u16(parent, rec_off); 411 hfs_bnode_write_u16(parent, rec_off, end_off + diff); 412 } 413 hfs_bnode_move(parent, start_off + diff, start_off, 414 end_off - start_off); 415 skip: 416 hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen); 417 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) 418 hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1); 419 hfs_bnode_dump(parent); 420 421 hfs_bnode_put(node); 422 node = parent; 423 424 if (new_node) { 425 __be32 cnid; 426 427 fd->bnode = hfs_bnode_find(tree, new_node->parent); 428 /* create index key and entry */ 429 hfs_bnode_read_key(new_node, fd->search_key, 14); 430 cnid = cpu_to_be32(new_node->this); 431 432 __hfs_brec_find(fd->bnode, fd); 433 hfs_brec_insert(fd, &cnid, sizeof(cnid)); 434 hfs_bnode_put(fd->bnode); 435 hfs_bnode_put(new_node); 436 437 if (!rec) { 438 if (new_node == node) 439 goto out; 440 /* restore search_key */ 441 hfs_bnode_read_key(node, fd->search_key, 14); 442 } 443 } 444 445 if (!rec && node->parent) 446 goto again; 447 out: 448 fd->bnode = node; 449 return 0; 450 } 451 452 static int hfs_btree_inc_height(struct hfs_btree *tree) 453 { 454 struct hfs_bnode *node, *new_node; 455 struct hfs_bnode_desc node_desc; 456 int key_size, rec; 457 __be32 cnid; 458 459 node = NULL; 460 if (tree->root) { 461 node = hfs_bnode_find(tree, tree->root); 462 if (IS_ERR(node)) 463 return PTR_ERR(node); 464 } 465 new_node = hfs_bmap_alloc(tree); 466 if (IS_ERR(new_node)) { 467 hfs_bnode_put(node); 468 return PTR_ERR(new_node); 469 } 470 471 tree->root = new_node->this; 472 if (!tree->depth) { 473 tree->leaf_head = tree->leaf_tail = new_node->this; 474 new_node->type = HFS_NODE_LEAF; 475 new_node->num_recs = 0; 476 } else { 477 new_node->type = HFS_NODE_INDEX; 478 new_node->num_recs = 1; 479 } 480 new_node->parent = 0; 481 new_node->next = 0; 482 new_node->prev = 0; 483 new_node->height = ++tree->depth; 484 485 node_desc.next = cpu_to_be32(new_node->next); 486 node_desc.prev = cpu_to_be32(new_node->prev); 487 node_desc.type = new_node->type; 488 node_desc.height = new_node->height; 489 node_desc.num_recs = cpu_to_be16(new_node->num_recs); 490 node_desc.reserved = 0; 491 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc)); 492 493 rec = tree->node_size - 2; 494 hfs_bnode_write_u16(new_node, rec, 14); 495 496 if (node) { 497 /* insert old root idx into new root */ 498 node->parent = tree->root; 499 if (node->type == HFS_NODE_LEAF || 500 tree->attributes & HFS_TREE_VARIDXKEYS) 501 key_size = hfs_bnode_read_u8(node, 14) + 1; 502 else 503 key_size = tree->max_key_len + 1; 504 hfs_bnode_copy(new_node, 14, node, 14, key_size); 505 506 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) { 507 key_size = tree->max_key_len + 1; 508 hfs_bnode_write_u8(new_node, 14, tree->max_key_len); 509 } 510 key_size = (key_size + 1) & -2; 511 cnid = cpu_to_be32(node->this); 512 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4); 513 514 rec -= 2; 515 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4); 516 517 hfs_bnode_put(node); 518 } 519 hfs_bnode_put(new_node); 520 mark_inode_dirty(tree->inode); 521 522 return 0; 523 } 524