fs/hfs/brec.c

   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 }