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 14static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd); 15static int hfs_brec_update_parent(struct hfs_find_data *fd); 16static int hfs_btree_inc_height(struct hfs_btree *tree); 17 18/* Get the length and offset of the given record in the given node */ 19u16 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 */ 31u16 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 65int 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 node = hfs_bnode_find(tree, tree->leaf_head); 79 if (IS_ERR(node)) 80 return PTR_ERR(node); 81 fd->bnode = node; 82 fd->record = -1; 83 } 84 new_node = NULL; 85 key_len = (fd->search_key->key_len | 1) + 1; 86again: 87 /* new record idx and complete record size */ 88 rec = fd->record + 1; 89 size = key_len + entry_len; 90 91 node = fd->bnode; 92 hfs_bnode_dump(node); 93 /* get last offset */ 94 end_rec_off = tree->node_size - (node->num_recs + 1) * 2; 95 end_off = hfs_bnode_read_u16(node, end_rec_off); 96 end_rec_off -= 2; 97 hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", 98 rec, size, end_off, end_rec_off); 99 if (size > end_rec_off - end_off) { 100 if (new_node) 101 panic("not enough room!\n"); 102 new_node = hfs_bnode_split(fd); 103 if (IS_ERR(new_node)) 104 return PTR_ERR(new_node); 105 goto again; 106 } 107 if (node->type == HFS_NODE_LEAF) { 108 tree->leaf_count++; 109 mark_inode_dirty(tree->inode); 110 } 111 node->num_recs++; 112 /* write new last offset */ 113 hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), 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 131skip: 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); 161 162 hfs_bnode_put(new_node); 163 new_node = NULL; 164 165 if (tree->attributes & HFS_TREE_VARIDXKEYS) 166 key_len = fd->search_key->key_len + 1; 167 else { 168 fd->search_key->key_len = tree->max_key_len; 169 key_len = tree->max_key_len + 1; 170 } 171 goto again; 172 } 173 174 return 0; 175} 176 177int hfs_brec_remove(struct hfs_find_data *fd) 178{ 179 struct hfs_btree *tree; 180 struct hfs_bnode *node, *parent; 181 int end_off, rec_off, data_off, size; 182 183 tree = fd->tree; 184 node = fd->bnode; 185again: 186 rec_off = tree->node_size - (fd->record + 2) * 2; 187 end_off = tree->node_size - (node->num_recs + 1) * 2; 188 189 if (node->type == HFS_NODE_LEAF) { 190 tree->leaf_count--; 191 mark_inode_dirty(tree->inode); 192 } 193 hfs_bnode_dump(node); 194 hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n", 195 fd->record, fd->keylength + fd->entrylength); 196 if (!--node->num_recs) { 197 hfs_bnode_unlink(node); 198 if (!node->parent) 199 return 0; 200 parent = hfs_bnode_find(tree, node->parent); 201 if (IS_ERR(parent)) 202 return PTR_ERR(parent); 203 hfs_bnode_put(node); 204 node = fd->bnode = parent; 205 206 __hfs_brec_find(node, fd); 207 goto again; 208 } 209 hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs); 210 211 if (rec_off == end_off) 212 goto skip; 213 size = fd->keylength + fd->entrylength; 214 215 do { 216 data_off = hfs_bnode_read_u16(node, rec_off); 217 hfs_bnode_write_u16(node, rec_off + 2, data_off - size); 218 rec_off -= 2; 219 } while (rec_off >= end_off); 220 221 /* fill hole */ 222 hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size, 223 data_off - fd->keyoffset - size); 224skip: 225 hfs_bnode_dump(node); 226 if (!fd->record) 227 hfs_brec_update_parent(fd); 228 return 0; 229} 230 231static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd) 232{ 233 struct hfs_btree *tree; 234 struct hfs_bnode *node, *new_node, *next_node; 235 struct hfs_bnode_desc node_desc; 236 int num_recs, new_rec_off, new_off, old_rec_off; 237 int data_start, data_end, size; 238 239 tree = fd->tree; 240 node = fd->bnode; 241 new_node = hfs_bmap_alloc(tree); 242 if (IS_ERR(new_node)) 243 return new_node; 244 hfs_bnode_get(node); 245 hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n", 246 node->this, new_node->this, node->next); 247 new_node->next = node->next; 248 new_node->prev = node->this; 249 new_node->parent = node->parent; 250 new_node->type = node->type; 251 new_node->height = node->height; 252 253 if (node->next) 254 next_node = hfs_bnode_find(tree, node->next); 255 else 256 next_node = NULL; 257 258 if (IS_ERR(next_node)) { 259 hfs_bnode_put(node); 260 hfs_bnode_put(new_node); 261 return next_node; 262 } 263 264 size = tree->node_size / 2 - node->num_recs * 2 - 14; 265 old_rec_off = tree->node_size - 4; 266 num_recs = 1; 267 for (;;) { 268 data_start = hfs_bnode_read_u16(node, old_rec_off); 269 if (data_start > size) 270 break; 271 old_rec_off -= 2; 272 if (++num_recs < node->num_recs) 273 continue; 274 /* panic? */ 275 hfs_bnode_put(node); 276 hfs_bnode_put(new_node); 277 if (next_node) 278 hfs_bnode_put(next_node); 279 return ERR_PTR(-ENOSPC); 280 } 281 282 if (fd->record + 1 < num_recs) { 283 /* new record is in the lower half, 284 * so leave some more space there 285 */ 286 old_rec_off += 2; 287 num_recs--; 288 data_start = hfs_bnode_read_u16(node, old_rec_off); 289 } else { 290 hfs_bnode_put(node); 291 hfs_bnode_get(new_node); 292 fd->bnode = new_node; 293 fd->record -= num_recs; 294 fd->keyoffset -= data_start - 14; 295 fd->entryoffset -= data_start - 14; 296 } 297 new_node->num_recs = node->num_recs - num_recs; 298 node->num_recs = num_recs; 299 300 new_rec_off = tree->node_size - 2; 301 new_off = 14; 302 size = data_start - new_off; 303 num_recs = new_node->num_recs; 304 data_end = data_start; 305 while (num_recs) { 306 hfs_bnode_write_u16(new_node, new_rec_off, new_off); 307 old_rec_off -= 2; 308 new_rec_off -= 2; 309 data_end = hfs_bnode_read_u16(node, old_rec_off); 310 new_off = data_end - size; 311 num_recs--; 312 } 313 hfs_bnode_write_u16(new_node, new_rec_off, new_off); 314 hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start); 315 316 /* update new bnode header */ 317 node_desc.next = cpu_to_be32(new_node->next); 318 node_desc.prev = cpu_to_be32(new_node->prev); 319 node_desc.type = new_node->type; 320 node_desc.height = new_node->height; 321 node_desc.num_recs = cpu_to_be16(new_node->num_recs); 322 node_desc.reserved = 0; 323 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc)); 324 325 /* update previous bnode header */ 326 node->next = new_node->this; 327 hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc)); 328 node_desc.next = cpu_to_be32(node->next); 329 node_desc.num_recs = cpu_to_be16(node->num_recs); 330 hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc)); 331 332 /* update next bnode header */ 333 if (next_node) { 334 next_node->prev = new_node->this; 335 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc)); 336 node_desc.prev = cpu_to_be32(next_node->prev); 337 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc)); 338 hfs_bnode_put(next_node); 339 } else if (node->this == tree->leaf_tail) { 340 /* if there is no next node, this might be the new tail */ 341 tree->leaf_tail = new_node->this; 342 mark_inode_dirty(tree->inode); 343 } 344 345 hfs_bnode_dump(node); 346 hfs_bnode_dump(new_node); 347 hfs_bnode_put(node); 348 349 return new_node; 350} 351 352static int hfs_brec_update_parent(struct hfs_find_data *fd) 353{ 354 struct hfs_btree *tree; 355 struct hfs_bnode *node, *new_node, *parent; 356 int newkeylen, diff; 357 int rec, rec_off, end_rec_off; 358 int start_off, end_off; 359 360 tree = fd->tree; 361 node = fd->bnode; 362 new_node = NULL; 363 if (!node->parent) 364 return 0; 365 366again: 367 parent = hfs_bnode_find(tree, node->parent); 368 if (IS_ERR(parent)) 369 return PTR_ERR(parent); 370 __hfs_brec_find(parent, fd); 371 if (fd->record < 0) 372 return -ENOENT; 373 hfs_bnode_dump(parent); 374 rec = fd->record; 375 376 /* size difference between old and new key */ 377 if (tree->attributes & HFS_TREE_VARIDXKEYS) 378 newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1; 379 else 380 fd->keylength = newkeylen = tree->max_key_len + 1; 381 hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n", 382 rec, fd->keylength, newkeylen); 383 384 rec_off = tree->node_size - (rec + 2) * 2; 385 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2; 386 diff = newkeylen - fd->keylength; 387 if (!diff) 388 goto skip; 389 if (diff > 0) { 390 end_off = hfs_bnode_read_u16(parent, end_rec_off); 391 if (end_rec_off - end_off < diff) { 392 393 printk(KERN_DEBUG "splitting index node...\n"); 394 fd->bnode = parent; 395 new_node = hfs_bnode_split(fd); 396 if (IS_ERR(new_node)) 397 return PTR_ERR(new_node); 398 parent = fd->bnode; 399 rec = fd->record; 400 rec_off = tree->node_size - (rec + 2) * 2; 401 end_rec_off = tree->node_size - (parent->num_recs + 1) * 2; 402 } 403 } 404 405 end_off = start_off = hfs_bnode_read_u16(parent, rec_off); 406 hfs_bnode_write_u16(parent, rec_off, start_off + diff); 407 start_off -= 4; /* move previous cnid too */ 408 409 while (rec_off > end_rec_off) { 410 rec_off -= 2; 411 end_off = hfs_bnode_read_u16(parent, rec_off); 412 hfs_bnode_write_u16(parent, rec_off, end_off + diff); 413 } 414 hfs_bnode_move(parent, start_off + diff, start_off, 415 end_off - start_off); 416skip: 417 hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen); 418 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) 419 hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1); 420 hfs_bnode_dump(parent); 421 422 hfs_bnode_put(node); 423 node = parent; 424 425 if (new_node) { 426 __be32 cnid; 427 428 if (!new_node->parent) { 429 hfs_btree_inc_height(tree); 430 new_node->parent = tree->root; 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); 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 new_node = NULL; 449 } 450 451 if (!rec && node->parent) 452 goto again; 453out: 454 fd->bnode = node; 455 return 0; 456} 457 458static int hfs_btree_inc_height(struct hfs_btree *tree) 459{ 460 struct hfs_bnode *node, *new_node; 461 struct hfs_bnode_desc node_desc; 462 int key_size, rec; 463 __be32 cnid; 464 465 node = NULL; 466 if (tree->root) { 467 node = hfs_bnode_find(tree, tree->root); 468 if (IS_ERR(node)) 469 return PTR_ERR(node); 470 } 471 new_node = hfs_bmap_alloc(tree); 472 if (IS_ERR(new_node)) { 473 hfs_bnode_put(node); 474 return PTR_ERR(new_node); 475 } 476 477 tree->root = new_node->this; 478 if (!tree->depth) { 479 tree->leaf_head = tree->leaf_tail = new_node->this; 480 new_node->type = HFS_NODE_LEAF; 481 new_node->num_recs = 0; 482 } else { 483 new_node->type = HFS_NODE_INDEX; 484 new_node->num_recs = 1; 485 } 486 new_node->parent = 0; 487 new_node->next = 0; 488 new_node->prev = 0; 489 new_node->height = ++tree->depth; 490 491 node_desc.next = cpu_to_be32(new_node->next); 492 node_desc.prev = cpu_to_be32(new_node->prev); 493 node_desc.type = new_node->type; 494 node_desc.height = new_node->height; 495 node_desc.num_recs = cpu_to_be16(new_node->num_recs); 496 node_desc.reserved = 0; 497 hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc)); 498 499 rec = tree->node_size - 2; 500 hfs_bnode_write_u16(new_node, rec, 14); 501 502 if (node) { 503 /* insert old root idx into new root */ 504 node->parent = tree->root; 505 if (node->type == HFS_NODE_LEAF || 506 tree->attributes & HFS_TREE_VARIDXKEYS) 507 key_size = hfs_bnode_read_u8(node, 14) + 1; 508 else 509 key_size = tree->max_key_len + 1; 510 hfs_bnode_copy(new_node, 14, node, 14, key_size); 511 512 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) { 513 key_size = tree->max_key_len + 1; 514 hfs_bnode_write_u8(new_node, 14, tree->max_key_len); 515 } 516 key_size = (key_size + 1) & -2; 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