1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/hfsplus/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 "hfsplus_fs.h" 13 #include "hfsplus_raw.h" 14 15 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd); 16 static int hfs_brec_update_parent(struct hfs_find_data *fd); 17 static int hfs_btree_inc_height(struct hfs_btree *); 18 19 /* Get the length and offset of the given record in the given node */ 20 u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off) 21 { 22 __be16 retval[2]; 23 u16 dataoff; 24 25 dataoff = node->tree->node_size - (rec + 2) * 2; 26 hfs_bnode_read(node, retval, dataoff, 4); 27 *off = be16_to_cpu(retval[1]); 28 return be16_to_cpu(retval[0]) - *off; 29 } 30 31 /* Get the length of the key from a keyed record */ 32 u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec) 33 { 34 u16 retval, recoff; 35 36 if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF) 37 return 0; 38 39 if ((node->type == HFS_NODE_INDEX) && 40 !(node->tree->attributes & HFS_TREE_VARIDXKEYS) && 41 (node->tree->cnid != HFSPLUS_ATTR_CNID)) { 42 retval = node->tree->max_key_len + 2; 43 } else { 44 recoff = hfs_bnode_read_u16(node, 45 node->tree->node_size - (rec + 1) * 2); 46 if (!recoff) 47 return 0; 48 if (recoff > node->tree->node_size - 2) { 49 pr_err("recoff %d too large\n", recoff); 50 return 0; 51 } 52 53 retval = hfs_bnode_read_u16(node, recoff) + 2; 54 if (retval > node->tree->max_key_len + 2) { 55 pr_err("keylen %d too large\n", 56 retval); 57 retval = 0; 58 } 59 } 60 return retval; 61 } 62 63 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len) 64 { 65 struct hfs_btree *tree; 66 struct hfs_bnode *node, *new_node; 67 int size, key_len, rec; 68 int data_off, end_off; 69 int idx_rec_off, data_rec_off, end_rec_off; 70 __be32 cnid; 71 72 tree = fd->tree; 73 if (!fd->bnode) { 74 if (!tree->root) 75 hfs_btree_inc_height(tree); 76 node = hfs_bnode_find(tree, tree->leaf_head); 77 if (IS_ERR(node)) 78 return PTR_ERR(node); 79 fd->bnode = node; 80 fd->record = -1; 81 } 82 new_node = NULL; 83 key_len = be16_to_cpu(fd->search_key->key_len) + 2; 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, 112 offsetof(struct hfs_bnode_desc, num_recs), 113 node->num_recs); 114 hfs_bnode_write_u16(node, end_rec_off, end_off + size); 115 data_off = end_off; 116 data_rec_off = end_rec_off + 2; 117 idx_rec_off = tree->node_size - (rec + 1) * 2; 118 if (idx_rec_off == data_rec_off) 119 goto skip; 120 /* move all following entries */ 121 do { 122 data_off = hfs_bnode_read_u16(node, data_rec_off + 2); 123 hfs_bnode_write_u16(node, data_rec_off, data_off + size); 124 data_rec_off += 2; 125 } while (data_rec_off < idx_rec_off); 126 127 /* move data away */ 128 hfs_bnode_move(node, data_off + size, data_off, 129 end_off - data_off); 130 131 skip: 132 hfs_bnode_write(node, fd->search_key, data_off, key_len); 133 hfs_bnode_write(node, entry, data_off + key_len, entry_len); 134 hfs_bnode_dump(node); 135 136 /* 137 * update parent key if we inserted a key 138 * at the start of the node and it is not the new node 139 */ 140 if (!rec && new_node != node) { 141 hfs_bnode_read_key(node, fd->search_key, data_off + size); 142 hfs_brec_update_parent(fd); 143 } 144 145 if (new_node) { 146 hfs_bnode_put(fd->bnode); 147 if (!new_node->parent) { 148 hfs_btree_inc_height(tree); 149 new_node->parent = tree->root; 150 } 151 fd->bnode = hfs_bnode_find(tree, new_node->parent); 152 153 /* create index data entry */ 154 cnid = cpu_to_be32(new_node->this); 155 entry = &cnid; 156 entry_len = sizeof(cnid); 157 158 /* get index key */ 159 hfs_bnode_read_key(new_node, fd->search_key, 14); 160 __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key); 161 162 hfs_bnode_put(new_node); 163 new_node = NULL; 164 165 if ((tree->attributes & HFS_TREE_VARIDXKEYS) || 166 (tree->cnid == HFSPLUS_ATTR_CNID)) 167 key_len = be16_to_cpu(fd->search_key->key_len) + 2; 168 else { 169 fd->search_key->key_len = 170 cpu_to_be16(tree->max_key_len); 171 key_len = tree->max_key_len + 2; 172 } 173 goto again; 174 } 175 176 return 0; 177 } 178 179 int hfs_brec_remove(struct hfs_find_data *fd) 180 { 181 struct hfs_btree *tree; 182 struct hfs_bnode *node, *parent; 183 int end_off, rec_off, data_off, size; 184 185 tree = fd->tree; 186 node = fd->bnode; 187 again: 188 rec_off = tree->node_size - (fd->record + 2) * 2; 189 end_off = tree->node_size - (node->num_recs + 1) * 2; 190 191 if (node->type == HFS_NODE_LEAF) { 192 tree->leaf_count--; 193 mark_inode_dirty(tree->inode); 194 } 195 hfs_bnode_dump(node); 196 hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n", 197 fd->record, fd->keylength + fd->entrylength); 198 if (!--node->num_recs) { 199 hfs_bnode_unlink(node); 200 if (!node->parent) 201 return 0; 202 parent = hfs_bnode_find(tree, node->parent); 203 if (IS_ERR(parent)) 204 return PTR_ERR(parent); 205 hfs_bnode_put(node); 206 node = fd->bnode = parent; 207 208 __hfs_brec_find(node, fd, hfs_find_rec_by_key); 209 goto again; 210 } 211 hfs_bnode_write_u16(node, 212 offsetof(struct hfs_bnode_desc, num_recs), 213 node->num_recs); 214 215 if (rec_off == end_off) 216 goto skip; 217 size = fd->keylength + fd->entrylength; 218 219 do { 220 data_off = hfs_bnode_read_u16(node, rec_off); 221 hfs_bnode_write_u16(node, rec_off + 2, data_off - size); 222 rec_off -= 2; 223 } while (rec_off >= end_off); 224 225 /* fill hole */ 226 hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size, 227 data_off - fd->keyoffset - size); 228 skip: 229 hfs_bnode_dump(node); 230 if (!fd->record) 231 hfs_brec_update_parent(fd); 232 return 0; 233 } 234 235 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd) 236 { 237 struct hfs_btree *tree; 238 struct hfs_bnode *node, *new_node, *next_node; 239 struct hfs_bnode_desc node_desc; 240 int num_recs, new_rec_off, new_off, old_rec_off; 241 int data_start, data_end, size; 242 243 tree = fd->tree; 244 node = fd->bnode; 245 new_node = hfs_bmap_alloc(tree); 246 if (IS_ERR(new_node)) 247 return new_node; 248 hfs_bnode_get(node); 249 hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n", 250 node->this, new_node->this, node->next); 251 new_node->next = node->next; 252 new_node->prev = node->this; 253 new_node->parent = node->parent; 254 new_node->type = node->type; 255 new_node->height = node->height; 256 257 if (node->next) 258 next_node = hfs_bnode_find(tree, node->next); 259 else 260 next_node = NULL; 261 262 if (IS_ERR(next_node)) { 263 hfs_bnode_put(node); 264 hfs_bnode_put(new_node); 265 return next_node; 266 } 267 268 size = tree->node_size / 2 - node->num_recs * 2 - 14; 269 old_rec_off = tree->node_size - 4; 270 num_recs = 1; 271 for (;;) { 272 data_start = hfs_bnode_read_u16(node, old_rec_off); 273 if (data_start > size) 274 break; 275 old_rec_off -= 2; 276 if (++num_recs < node->num_recs) 277 continue; 278 /* panic? */ 279 hfs_bnode_put(node); 280 hfs_bnode_put(new_node); 281 if (next_node) 282 hfs_bnode_put(next_node); 283 return ERR_PTR(-ENOSPC); 284 } 285 286 if (fd->record + 1 < num_recs) { 287 /* new record is in the lower half, 288 * so leave some more space there 289 */ 290 old_rec_off += 2; 291 num_recs--; 292 data_start = hfs_bnode_read_u16(node, old_rec_off); 293 } else { 294 hfs_bnode_put(node); 295 hfs_bnode_get(new_node); 296 fd->bnode = new_node; 297 fd->record -= num_recs; 298 fd->keyoffset -= data_start - 14; 299 fd->entryoffset -= data_start - 14; 300 } 301 new_node->num_recs = node->num_recs - num_recs; 302 node->num_recs = num_recs; 303 304 new_rec_off = tree->node_size - 2; 305 new_off = 14; 306 size = data_start - new_off; 307 num_recs = new_node->num_recs; 308 data_end = data_start; 309 while (num_recs) { 310 hfs_bnode_write_u16(new_node, new_rec_off, new_off); 311 old_rec_off -= 2; 312 new_rec_off -= 2; 313 data_end = hfs_bnode_read_u16(node, old_rec_off); 314 new_off = data_end - size; 315 num_recs--; 316 } 317 hfs_bnode_write_u16(new_node, new_rec_off, new_off); 318 hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start); 319 320 /* update new bnode header */ 321 node_desc.next = cpu_to_be32(new_node->next); 322 node_desc.prev = cpu_to_be32(new_node->prev); 323 node_desc.type = new_node->type; 324 node_desc.height = new_node->height; 325 node_desc.num_recs = cpu_to_be16(new_node->num_recs); 326 node_desc.reserved = 0; 327 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc)); 328 329 /* update previous bnode header */ 330 node->next = new_node->this; 331 hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc)); 332 node_desc.next = cpu_to_be32(node->next); 333 node_desc.num_recs = cpu_to_be16(node->num_recs); 334 hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc)); 335 336 /* update next bnode header */ 337 if (next_node) { 338 next_node->prev = new_node->this; 339 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc)); 340 node_desc.prev = cpu_to_be32(next_node->prev); 341 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc)); 342 hfs_bnode_put(next_node); 343 } else if (node->this == tree->leaf_tail) { 344 /* if there is no next node, this might be the new tail */ 345 tree->leaf_tail = new_node->this; 346 mark_inode_dirty(tree->inode); 347 } 348 349 hfs_bnode_dump(node); 350 hfs_bnode_dump(new_node); 351 hfs_bnode_put(node); 352 353 return new_node; 354 } 355 356 static int hfs_brec_update_parent(struct hfs_find_data *fd) 357 { 358 struct hfs_btree *tree; 359 struct hfs_bnode *node, *new_node, *parent; 360 int newkeylen, diff; 361 int rec, rec_off, end_rec_off; 362 int start_off, end_off; 363 364 tree = fd->tree; 365 node = fd->bnode; 366 new_node = NULL; 367 if (!node->parent) 368 return 0; 369 370 again: 371 parent = hfs_bnode_find(tree, node->parent); 372 if (IS_ERR(parent)) 373 return PTR_ERR(parent); 374 __hfs_brec_find(parent, fd, hfs_find_rec_by_key); 375 if (fd->record < 0) 376 return -ENOENT; 377 hfs_bnode_dump(parent); 378 rec = fd->record; 379 380 /* size difference between old and new key */ 381 if ((tree->attributes & HFS_TREE_VARIDXKEYS) || 382 (tree->cnid == HFSPLUS_ATTR_CNID)) 383 newkeylen = hfs_bnode_read_u16(node, 14) + 2; 384 else 385 fd->keylength = newkeylen = tree->max_key_len + 2; 386 hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n", 387 rec, fd->keylength, newkeylen); 388 389 rec_off = tree->node_size - (rec + 2) * 2; 390 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2; 391 diff = newkeylen - fd->keylength; 392 if (!diff) 393 goto skip; 394 if (diff > 0) { 395 end_off = hfs_bnode_read_u16(parent, end_rec_off); 396 if (end_rec_off - end_off < diff) { 397 398 hfs_dbg(BNODE_MOD, "splitting index node\n"); 399 fd->bnode = parent; 400 new_node = hfs_bnode_split(fd); 401 if (IS_ERR(new_node)) 402 return PTR_ERR(new_node); 403 parent = fd->bnode; 404 rec = fd->record; 405 rec_off = tree->node_size - (rec + 2) * 2; 406 end_rec_off = tree->node_size - 407 (parent->num_recs + 1) * 2; 408 } 409 } 410 411 end_off = start_off = hfs_bnode_read_u16(parent, rec_off); 412 hfs_bnode_write_u16(parent, rec_off, start_off + diff); 413 start_off -= 4; /* move previous cnid too */ 414 415 while (rec_off > end_rec_off) { 416 rec_off -= 2; 417 end_off = hfs_bnode_read_u16(parent, rec_off); 418 hfs_bnode_write_u16(parent, rec_off, end_off + diff); 419 } 420 hfs_bnode_move(parent, start_off + diff, start_off, 421 end_off - start_off); 422 skip: 423 hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen); 424 hfs_bnode_dump(parent); 425 426 hfs_bnode_put(node); 427 node = parent; 428 429 if (new_node) { 430 __be32 cnid; 431 432 fd->bnode = hfs_bnode_find(tree, new_node->parent); 433 /* create index key and entry */ 434 hfs_bnode_read_key(new_node, fd->search_key, 14); 435 cnid = cpu_to_be32(new_node->this); 436 437 __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key); 438 hfs_brec_insert(fd, &cnid, sizeof(cnid)); 439 hfs_bnode_put(fd->bnode); 440 hfs_bnode_put(new_node); 441 442 if (!rec) { 443 if (new_node == node) 444 goto out; 445 /* restore search_key */ 446 hfs_bnode_read_key(node, fd->search_key, 14); 447 } 448 } 449 450 if (!rec && node->parent) 451 goto again; 452 out: 453 fd->bnode = node; 454 return 0; 455 } 456 457 static int hfs_btree_inc_height(struct hfs_btree *tree) 458 { 459 struct hfs_bnode *node, *new_node; 460 struct hfs_bnode_desc node_desc; 461 int key_size, rec; 462 __be32 cnid; 463 464 node = NULL; 465 if (tree->root) { 466 node = hfs_bnode_find(tree, tree->root); 467 if (IS_ERR(node)) 468 return PTR_ERR(node); 469 } 470 new_node = hfs_bmap_alloc(tree); 471 if (IS_ERR(new_node)) { 472 hfs_bnode_put(node); 473 return PTR_ERR(new_node); 474 } 475 476 tree->root = new_node->this; 477 if (!tree->depth) { 478 tree->leaf_head = tree->leaf_tail = new_node->this; 479 new_node->type = HFS_NODE_LEAF; 480 new_node->num_recs = 0; 481 } else { 482 new_node->type = HFS_NODE_INDEX; 483 new_node->num_recs = 1; 484 } 485 new_node->parent = 0; 486 new_node->next = 0; 487 new_node->prev = 0; 488 new_node->height = ++tree->depth; 489 490 node_desc.next = cpu_to_be32(new_node->next); 491 node_desc.prev = cpu_to_be32(new_node->prev); 492 node_desc.type = new_node->type; 493 node_desc.height = new_node->height; 494 node_desc.num_recs = cpu_to_be16(new_node->num_recs); 495 node_desc.reserved = 0; 496 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc)); 497 498 rec = tree->node_size - 2; 499 hfs_bnode_write_u16(new_node, rec, 14); 500 501 if (node) { 502 /* insert old root idx into new root */ 503 node->parent = tree->root; 504 if (node->type == HFS_NODE_LEAF || 505 tree->attributes & HFS_TREE_VARIDXKEYS || 506 tree->cnid == HFSPLUS_ATTR_CNID) 507 key_size = hfs_bnode_read_u16(node, 14) + 2; 508 else 509 key_size = tree->max_key_len + 2; 510 hfs_bnode_copy(new_node, 14, node, 14, key_size); 511 512 if (!(tree->attributes & HFS_TREE_VARIDXKEYS) && 513 (tree->cnid != HFSPLUS_ATTR_CNID)) { 514 key_size = tree->max_key_len + 2; 515 hfs_bnode_write_u16(new_node, 14, tree->max_key_len); 516 } 517 cnid = cpu_to_be32(node->this); 518 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4); 519 520 rec -= 2; 521 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4); 522 523 hfs_bnode_put(node); 524 } 525 hfs_bnode_put(new_node); 526 mark_inode_dirty(tree->inode); 527 528 return 0; 529 } 530