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