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                 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;
  86 again:
  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
 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);
 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
 177 int 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;
 185 again:
 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);
 224 skip:
 225         hfs_bnode_dump(node);
 226         if (!fd->record)
 227                 hfs_brec_update_parent(fd);
 228         return 0;
 229 }
 230
 231 static 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
 352 static 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
 366 again:
 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);
 416 skip:
 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                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 429                 /* create index key and entry */
 430                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 431                 cnid = cpu_to_be32(new_node->this);
 432
 433                 __hfs_brec_find(fd->bnode, fd);
 434                 hfs_brec_insert(fd, &cnid, sizeof(cnid));
 435                 hfs_bnode_put(fd->bnode);
 436                 hfs_bnode_put(new_node);
 437
 438                 if (!rec) {
 439                         if (new_node == node)
 440                                 goto out;
 441                         /* restore search_key */
 442                         hfs_bnode_read_key(node, fd->search_key, 14);
 443                 }
 444         }
 445
 446         if (!rec && node->parent)
 447                 goto again;
 448 out:
 449         fd->bnode = node;
 450         return 0;
 451 }
 452
 453 static int hfs_btree_inc_height(struct hfs_btree *tree)
 454 {
 455         struct hfs_bnode *node, *new_node;
 456         struct hfs_bnode_desc node_desc;
 457         int key_size, rec;
 458         __be32 cnid;
 459
 460         node = NULL;
 461         if (tree->root) {
 462                 node = hfs_bnode_find(tree, tree->root);
 463                 if (IS_ERR(node))
 464                         return PTR_ERR(node);
 465         }
 466         new_node = hfs_bmap_alloc(tree);
 467         if (IS_ERR(new_node)) {
 468                 hfs_bnode_put(node);
 469                 return PTR_ERR(new_node);
 470         }
 471
 472         tree->root = new_node->this;
 473         if (!tree->depth) {
 474                 tree->leaf_head = tree->leaf_tail = new_node->this;
 475                 new_node->type = HFS_NODE_LEAF;
 476                 new_node->num_recs = 0;
 477         } else {
 478                 new_node->type = HFS_NODE_INDEX;
 479                 new_node->num_recs = 1;
 480         }
 481         new_node->parent = 0;
 482         new_node->next = 0;
 483         new_node->prev = 0;
 484         new_node->height = ++tree->depth;
 485
 486         node_desc.next = cpu_to_be32(new_node->next);
 487         node_desc.prev = cpu_to_be32(new_node->prev);
 488         node_desc.type = new_node->type;
 489         node_desc.height = new_node->height;
 490         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 491         node_desc.reserved = 0;
 492         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 493
 494         rec = tree->node_size - 2;
 495         hfs_bnode_write_u16(new_node, rec, 14);
 496
 497         if (node) {
 498                 /* insert old root idx into new root */
 499                 node->parent = tree->root;
 500                 if (node->type == HFS_NODE_LEAF ||
 501                     tree->attributes & HFS_TREE_VARIDXKEYS)
 502                         key_size = hfs_bnode_read_u8(node, 14) + 1;
 503                 else
 504                         key_size = tree->max_key_len + 1;
 505                 hfs_bnode_copy(new_node, 14, node, 14, key_size);
 506
 507                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
 508                         key_size = tree->max_key_len + 1;
 509                         hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
 510                 }
 511                 key_size = (key_size + 1) & -2;
 512                 cnid = cpu_to_be32(node->this);
 513                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 514
 515                 rec -= 2;
 516                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 517
 518                 hfs_bnode_put(node);
 519         }
 520         hfs_bnode_put(new_node);
 521         mark_inode_dirty(tree->inode);
 522
 523         return 0;
 524 }