fs/hfsplus/brec.c

   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                 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  77                 if (IS_ERR(fd->bnode))
  78                         return PTR_ERR(fd->bnode);
  79                 fd->record = -1;
  80         }
  81         new_node = NULL;
  82         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
  83 again:
  84         /* new record idx and complete record size */
  85         rec = fd->record + 1;
  86         size = key_len + entry_len;
  87
  88         node = fd->bnode;
  89         hfs_bnode_dump(node);
  90         /* get last offset */
  91         end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  92         end_off = hfs_bnode_read_u16(node, end_rec_off);
  93         end_rec_off -= 2;
  94         hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
  95                 rec, size, end_off, end_rec_off);
  96         if (size > end_rec_off - end_off) {
  97                 if (new_node)
  98                         panic("not enough room!\n");
  99                 new_node = hfs_bnode_split(fd);
 100                 if (IS_ERR(new_node))
 101                         return PTR_ERR(new_node);
 102                 goto again;
 103         }
 104         if (node->type == HFS_NODE_LEAF) {
 105                 tree->leaf_count++;
 106                 mark_inode_dirty(tree->inode);
 107         }
 108         node->num_recs++;
 109         /* write new last offset */
 110         hfs_bnode_write_u16(node,
 111                 offsetof(struct hfs_bnode_desc, num_recs),
 112                 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, hfs_find_rec_by_key);
 160
 161                 hfs_bnode_put(new_node);
 162                 new_node = NULL;
 163
 164                 if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
 165                                 (tree->cnid == HFSPLUS_ATTR_CNID))
 166                         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
 167                 else {
 168                         fd->search_key->key_len =
 169                                 cpu_to_be16(tree->max_key_len);
 170                         key_len = tree->max_key_len + 2;
 171                 }
 172                 goto again;
 173         }
 174
 175         return 0;
 176 }
 177
 178 int hfs_brec_remove(struct hfs_find_data *fd)
 179 {
 180         struct hfs_btree *tree;
 181         struct hfs_bnode *node, *parent;
 182         int end_off, rec_off, data_off, size;
 183
 184         tree = fd->tree;
 185         node = fd->bnode;
 186 again:
 187         rec_off = tree->node_size - (fd->record + 2) * 2;
 188         end_off = tree->node_size - (node->num_recs + 1) * 2;
 189
 190         if (node->type == HFS_NODE_LEAF) {
 191                 tree->leaf_count--;
 192                 mark_inode_dirty(tree->inode);
 193         }
 194         hfs_bnode_dump(node);
 195         hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n",
 196                 fd->record, fd->keylength + fd->entrylength);
 197         if (!--node->num_recs) {
 198                 hfs_bnode_unlink(node);
 199                 if (!node->parent)
 200                         return 0;
 201                 parent = hfs_bnode_find(tree, node->parent);
 202                 if (IS_ERR(parent))
 203                         return PTR_ERR(parent);
 204                 hfs_bnode_put(node);
 205                 node = fd->bnode = parent;
 206
 207                 __hfs_brec_find(node, fd, hfs_find_rec_by_key);
 208                 goto again;
 209         }
 210         hfs_bnode_write_u16(node,
 211                 offsetof(struct hfs_bnode_desc, num_recs),
 212                 node->num_recs);
 213
 214         if (rec_off == end_off)
 215                 goto skip;
 216         size = fd->keylength + fd->entrylength;
 217
 218         do {
 219                 data_off = hfs_bnode_read_u16(node, rec_off);
 220                 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
 221                 rec_off -= 2;
 222         } while (rec_off >= end_off);
 223
 224         /* fill hole */
 225         hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
 226                        data_off - fd->keyoffset - size);
 227 skip:
 228         hfs_bnode_dump(node);
 229         if (!fd->record)
 230                 hfs_brec_update_parent(fd);
 231         return 0;
 232 }
 233
 234 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
 235 {
 236         struct hfs_btree *tree;
 237         struct hfs_bnode *node, *new_node, *next_node;
 238         struct hfs_bnode_desc node_desc;
 239         int num_recs, new_rec_off, new_off, old_rec_off;
 240         int data_start, data_end, size;
 241
 242         tree = fd->tree;
 243         node = fd->bnode;
 244         new_node = hfs_bmap_alloc(tree);
 245         if (IS_ERR(new_node))
 246                 return new_node;
 247         hfs_bnode_get(node);
 248         hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n",
 249                 node->this, new_node->this, node->next);
 250         new_node->next = node->next;
 251         new_node->prev = node->this;
 252         new_node->parent = node->parent;
 253         new_node->type = node->type;
 254         new_node->height = node->height;
 255
 256         if (node->next)
 257                 next_node = hfs_bnode_find(tree, node->next);
 258         else
 259                 next_node = NULL;
 260
 261         if (IS_ERR(next_node)) {
 262                 hfs_bnode_put(node);
 263                 hfs_bnode_put(new_node);
 264                 return next_node;
 265         }
 266
 267         size = tree->node_size / 2 - node->num_recs * 2 - 14;
 268         old_rec_off = tree->node_size - 4;
 269         num_recs = 1;
 270         for (;;) {
 271                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 272                 if (data_start > size)
 273                         break;
 274                 old_rec_off -= 2;
 275                 if (++num_recs < node->num_recs)
 276                         continue;
 277                 /* panic? */
 278                 hfs_bnode_put(node);
 279                 hfs_bnode_put(new_node);
 280                 if (next_node)
 281                         hfs_bnode_put(next_node);
 282                 return ERR_PTR(-ENOSPC);
 283         }
 284
 285         if (fd->record + 1 < num_recs) {
 286                 /* new record is in the lower half,
 287                  * so leave some more space there
 288                  */
 289                 old_rec_off += 2;
 290                 num_recs--;
 291                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 292         } else {
 293                 hfs_bnode_put(node);
 294                 hfs_bnode_get(new_node);
 295                 fd->bnode = new_node;
 296                 fd->record -= num_recs;
 297                 fd->keyoffset -= data_start - 14;
 298                 fd->entryoffset -= data_start - 14;
 299         }
 300         new_node->num_recs = node->num_recs - num_recs;
 301         node->num_recs = num_recs;
 302
 303         new_rec_off = tree->node_size - 2;
 304         new_off = 14;
 305         size = data_start - new_off;
 306         num_recs = new_node->num_recs;
 307         data_end = data_start;
 308         while (num_recs) {
 309                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 310                 old_rec_off -= 2;
 311                 new_rec_off -= 2;
 312                 data_end = hfs_bnode_read_u16(node, old_rec_off);
 313                 new_off = data_end - size;
 314                 num_recs--;
 315         }
 316         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 317         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 318
 319         /* update new bnode header */
 320         node_desc.next = cpu_to_be32(new_node->next);
 321         node_desc.prev = cpu_to_be32(new_node->prev);
 322         node_desc.type = new_node->type;
 323         node_desc.height = new_node->height;
 324         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 325         node_desc.reserved = 0;
 326         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 327
 328         /* update previous bnode header */
 329         node->next = new_node->this;
 330         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 331         node_desc.next = cpu_to_be32(node->next);
 332         node_desc.num_recs = cpu_to_be16(node->num_recs);
 333         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 334
 335         /* update next bnode header */
 336         if (next_node) {
 337                 next_node->prev = new_node->this;
 338                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 339                 node_desc.prev = cpu_to_be32(next_node->prev);
 340                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 341                 hfs_bnode_put(next_node);
 342         } else if (node->this == tree->leaf_tail) {
 343                 /* if there is no next node, this might be the new tail */
 344                 tree->leaf_tail = new_node->this;
 345                 mark_inode_dirty(tree->inode);
 346         }
 347
 348         hfs_bnode_dump(node);
 349         hfs_bnode_dump(new_node);
 350         hfs_bnode_put(node);
 351
 352         return new_node;
 353 }
 354
 355 static int hfs_brec_update_parent(struct hfs_find_data *fd)
 356 {
 357         struct hfs_btree *tree;
 358         struct hfs_bnode *node, *new_node, *parent;
 359         int newkeylen, diff;
 360         int rec, rec_off, end_rec_off;
 361         int start_off, end_off;
 362
 363         tree = fd->tree;
 364         node = fd->bnode;
 365         new_node = NULL;
 366         if (!node->parent)
 367                 return 0;
 368
 369 again:
 370         parent = hfs_bnode_find(tree, node->parent);
 371         if (IS_ERR(parent))
 372                 return PTR_ERR(parent);
 373         __hfs_brec_find(parent, fd, hfs_find_rec_by_key);
 374         if (fd->record < 0)
 375                 return -ENOENT;
 376         hfs_bnode_dump(parent);
 377         rec = fd->record;
 378
 379         /* size difference between old and new key */
 380         if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
 381                                 (tree->cnid == HFSPLUS_ATTR_CNID))
 382                 newkeylen = hfs_bnode_read_u16(node, 14) + 2;
 383         else
 384                 fd->keylength = newkeylen = tree->max_key_len + 2;
 385         hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n",
 386                 rec, fd->keylength, newkeylen);
 387
 388         rec_off = tree->node_size - (rec + 2) * 2;
 389         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 390         diff = newkeylen - fd->keylength;
 391         if (!diff)
 392                 goto skip;
 393         if (diff > 0) {
 394                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
 395                 if (end_rec_off - end_off < diff) {
 396
 397                         hfs_dbg(BNODE_MOD, "splitting index node\n");
 398                         fd->bnode = parent;
 399                         new_node = hfs_bnode_split(fd);
 400                         if (IS_ERR(new_node))
 401                                 return PTR_ERR(new_node);
 402                         parent = fd->bnode;
 403                         rec = fd->record;
 404                         rec_off = tree->node_size - (rec + 2) * 2;
 405                         end_rec_off = tree->node_size -
 406                                 (parent->num_recs + 1) * 2;
 407                 }
 408         }
 409
 410         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 411         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 412         start_off -= 4; /* move previous cnid too */
 413
 414         while (rec_off > end_rec_off) {
 415                 rec_off -= 2;
 416                 end_off = hfs_bnode_read_u16(parent, rec_off);
 417                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 418         }
 419         hfs_bnode_move(parent, start_off + diff, start_off,
 420                        end_off - start_off);
 421 skip:
 422         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 423         hfs_bnode_dump(parent);
 424
 425         hfs_bnode_put(node);
 426         node = parent;
 427
 428         if (new_node) {
 429                 __be32 cnid;
 430
 431                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 432                 /* create index key and entry */
 433                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 434                 cnid = cpu_to_be32(new_node->this);
 435
 436                 __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key);
 437                 hfs_brec_insert(fd, &cnid, sizeof(cnid));
 438                 hfs_bnode_put(fd->bnode);
 439                 hfs_bnode_put(new_node);
 440
 441                 if (!rec) {
 442                         if (new_node == node)
 443                                 goto out;
 444                         /* restore search_key */
 445                         hfs_bnode_read_key(node, fd->search_key, 14);
 446                 }
 447         }
 448
 449         if (!rec && node->parent)
 450                 goto again;
 451 out:
 452         fd->bnode = node;
 453         return 0;
 454 }
 455
 456 static int hfs_btree_inc_height(struct hfs_btree *tree)
 457 {
 458         struct hfs_bnode *node, *new_node;
 459         struct hfs_bnode_desc node_desc;
 460         int key_size, rec;
 461         __be32 cnid;
 462
 463         node = NULL;
 464         if (tree->root) {
 465                 node = hfs_bnode_find(tree, tree->root);
 466                 if (IS_ERR(node))
 467                         return PTR_ERR(node);
 468         }
 469         new_node = hfs_bmap_alloc(tree);
 470         if (IS_ERR(new_node)) {
 471                 hfs_bnode_put(node);
 472                 return PTR_ERR(new_node);
 473         }
 474
 475         tree->root = new_node->this;
 476         if (!tree->depth) {
 477                 tree->leaf_head = tree->leaf_tail = new_node->this;
 478                 new_node->type = HFS_NODE_LEAF;
 479                 new_node->num_recs = 0;
 480         } else {
 481                 new_node->type = HFS_NODE_INDEX;
 482                 new_node->num_recs = 1;
 483         }
 484         new_node->parent = 0;
 485         new_node->next = 0;
 486         new_node->prev = 0;
 487         new_node->height = ++tree->depth;
 488
 489         node_desc.next = cpu_to_be32(new_node->next);
 490         node_desc.prev = cpu_to_be32(new_node->prev);
 491         node_desc.type = new_node->type;
 492         node_desc.height = new_node->height;
 493         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 494         node_desc.reserved = 0;
 495         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 496
 497         rec = tree->node_size - 2;
 498         hfs_bnode_write_u16(new_node, rec, 14);
 499
 500         if (node) {
 501                 /* insert old root idx into new root */
 502                 node->parent = tree->root;
 503                 if (node->type == HFS_NODE_LEAF ||
 504                                 tree->attributes & HFS_TREE_VARIDXKEYS ||
 505                                 tree->cnid == HFSPLUS_ATTR_CNID)
 506                         key_size = hfs_bnode_read_u16(node, 14) + 2;
 507                 else
 508                         key_size = tree->max_key_len + 2;
 509                 hfs_bnode_copy(new_node, 14, node, 14, key_size);
 510
 511                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS) &&
 512                                 (tree->cnid != HFSPLUS_ATTR_CNID)) {
 513                         key_size = tree->max_key_len + 2;
 514                         hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
 515                 }
 516                 cnid = cpu_to_be32(node->this);
 517                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 518
 519                 rec -= 2;
 520                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 521
 522                 hfs_bnode_put(node);
 523         }
 524         hfs_bnode_put(new_node);
 525         mark_inode_dirty(tree->inode);
 526
 527         return 0;
 528 }