LXR linux/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
  15static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
  16static int hfs_brec_update_parent(struct hfs_find_data *fd);
  17static int hfs_btree_inc_height(struct hfs_btree *);
  18
  19/* Get the length and offset of the given record in the given node */
  20u16 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 */
  32u16 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
  63int 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;
  83again:
  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
 130skip:
 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
 178int 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;
 186again:
 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);
 227skip:
 228        hfs_bnode_dump(node);
 229        if (!fd->record)
 230                hfs_brec_update_parent(fd);
 231        return 0;
 232}
 233
 234static 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
 355static 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
 369again:
 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);
 421skip:
 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;
 451out:
 452        fd->bnode = node;
 453        return 0;
 454}
 455
 456static 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}
 529