linux/fs/hfs/brec.c
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   1/*
   2 *  linux/fs/hfs/brec.c
   3 *
   4 * Copyright (C) 2001
   5 * Brad Boyer (flar@allandria.com)
   6 * (C) 2003 Ardis Technologies <roman@ardistech.com>
   7 *
   8 * Handle individual btree records
   9 */
  10
  11#include "btree.h"
  12
  13static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
  14static int hfs_brec_update_parent(struct hfs_find_data *fd);
  15static int hfs_btree_inc_height(struct hfs_btree *tree);
  16
  17/* Get the length and offset of the given record in the given node */
  18u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
  19{
  20        __be16 retval[2];
  21        u16 dataoff;
  22
  23        dataoff = node->tree->node_size - (rec + 2) * 2;
  24        hfs_bnode_read(node, retval, dataoff, 4);
  25        *off = be16_to_cpu(retval[1]);
  26        return be16_to_cpu(retval[0]) - *off;
  27}
  28
  29/* Get the length of the key from a keyed record */
  30u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
  31{
  32        u16 retval, recoff;
  33
  34        if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
  35                return 0;
  36
  37        if ((node->type == HFS_NODE_INDEX) &&
  38           !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
  39                if (node->tree->attributes & HFS_TREE_BIGKEYS)
  40                        retval = node->tree->max_key_len + 2;
  41                else
  42                        retval = node->tree->max_key_len + 1;
  43        } else {
  44                recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
  45                if (!recoff)
  46                        return 0;
  47                if (node->tree->attributes & HFS_TREE_BIGKEYS) {
  48                        retval = hfs_bnode_read_u16(node, recoff) + 2;
  49                        if (retval > node->tree->max_key_len + 2) {
  50                                pr_err("keylen %d too large\n", retval);
  51                                retval = 0;
  52                        }
  53                } else {
  54                        retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
  55                        if (retval > node->tree->max_key_len + 1) {
  56                                pr_err("keylen %d too large\n", retval);
  57                                retval = 0;
  58                        }
  59                }
  60        }
  61        return retval;
  62}
  63
  64int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  65{
  66        struct hfs_btree *tree;
  67        struct hfs_bnode *node, *new_node;
  68        int size, key_len, rec;
  69        int data_off, end_off;
  70        int idx_rec_off, data_rec_off, end_rec_off;
  71        __be32 cnid;
  72
  73        tree = fd->tree;
  74        if (!fd->bnode) {
  75                if (!tree->root)
  76                        hfs_btree_inc_height(tree);
  77                fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  78                if (IS_ERR(fd->bnode))
  79                        return PTR_ERR(fd->bnode);
  80                fd->record = -1;
  81        }
  82        new_node = NULL;
  83        key_len = (fd->search_key->key_len | 1) + 1;
  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, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 112        hfs_bnode_write_u16(node, end_rec_off, end_off + size);
 113        data_off = end_off;
 114        data_rec_off = end_rec_off + 2;
 115        idx_rec_off = tree->node_size - (rec + 1) * 2;
 116        if (idx_rec_off == data_rec_off)
 117                goto skip;
 118        /* move all following entries */
 119        do {
 120                data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
 121                hfs_bnode_write_u16(node, data_rec_off, data_off + size);
 122                data_rec_off += 2;
 123        } while (data_rec_off < idx_rec_off);
 124
 125        /* move data away */
 126        hfs_bnode_move(node, data_off + size, data_off,
 127                       end_off - data_off);
 128
 129skip:
 130        hfs_bnode_write(node, fd->search_key, data_off, key_len);
 131        hfs_bnode_write(node, entry, data_off + key_len, entry_len);
 132        hfs_bnode_dump(node);
 133
 134        if (new_node) {
 135                /* update parent key if we inserted a key
 136                 * at the start of the first node
 137                 */
 138                if (!rec && new_node != node)
 139                        hfs_brec_update_parent(fd);
 140
 141                hfs_bnode_put(fd->bnode);
 142                if (!new_node->parent) {
 143                        hfs_btree_inc_height(tree);
 144                        new_node->parent = tree->root;
 145                }
 146                fd->bnode = hfs_bnode_find(tree, new_node->parent);
 147
 148                /* create index data entry */
 149                cnid = cpu_to_be32(new_node->this);
 150                entry = &cnid;
 151                entry_len = sizeof(cnid);
 152
 153                /* get index key */
 154                hfs_bnode_read_key(new_node, fd->search_key, 14);
 155                __hfs_brec_find(fd->bnode, fd);
 156
 157                hfs_bnode_put(new_node);
 158                new_node = NULL;
 159
 160                if (tree->attributes & HFS_TREE_VARIDXKEYS)
 161                        key_len = fd->search_key->key_len + 1;
 162                else {
 163                        fd->search_key->key_len = tree->max_key_len;
 164                        key_len = tree->max_key_len + 1;
 165                }
 166                goto again;
 167        }
 168
 169        if (!rec)
 170                hfs_brec_update_parent(fd);
 171
 172        return 0;
 173}
 174
 175int hfs_brec_remove(struct hfs_find_data *fd)
 176{
 177        struct hfs_btree *tree;
 178        struct hfs_bnode *node, *parent;
 179        int end_off, rec_off, data_off, size;
 180
 181        tree = fd->tree;
 182        node = fd->bnode;
 183again:
 184        rec_off = tree->node_size - (fd->record + 2) * 2;
 185        end_off = tree->node_size - (node->num_recs + 1) * 2;
 186
 187        if (node->type == HFS_NODE_LEAF) {
 188                tree->leaf_count--;
 189                mark_inode_dirty(tree->inode);
 190        }
 191        hfs_bnode_dump(node);
 192        hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n",
 193                fd->record, fd->keylength + fd->entrylength);
 194        if (!--node->num_recs) {
 195                hfs_bnode_unlink(node);
 196                if (!node->parent)
 197                        return 0;
 198                parent = hfs_bnode_find(tree, node->parent);
 199                if (IS_ERR(parent))
 200                        return PTR_ERR(parent);
 201                hfs_bnode_put(node);
 202                node = fd->bnode = parent;
 203
 204                __hfs_brec_find(node, fd);
 205                goto again;
 206        }
 207        hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 208
 209        if (rec_off == end_off)
 210                goto skip;
 211        size = fd->keylength + fd->entrylength;
 212
 213        do {
 214                data_off = hfs_bnode_read_u16(node, rec_off);
 215                hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
 216                rec_off -= 2;
 217        } while (rec_off >= end_off);
 218
 219        /* fill hole */
 220        hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
 221                       data_off - fd->keyoffset - size);
 222skip:
 223        hfs_bnode_dump(node);
 224        if (!fd->record)
 225                hfs_brec_update_parent(fd);
 226        return 0;
 227}
 228
 229static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
 230{
 231        struct hfs_btree *tree;
 232        struct hfs_bnode *node, *new_node, *next_node;
 233        struct hfs_bnode_desc node_desc;
 234        int num_recs, new_rec_off, new_off, old_rec_off;
 235        int data_start, data_end, size;
 236
 237        tree = fd->tree;
 238        node = fd->bnode;
 239        new_node = hfs_bmap_alloc(tree);
 240        if (IS_ERR(new_node))
 241                return new_node;
 242        hfs_bnode_get(node);
 243        hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n",
 244                node->this, new_node->this, node->next);
 245        new_node->next = node->next;
 246        new_node->prev = node->this;
 247        new_node->parent = node->parent;
 248        new_node->type = node->type;
 249        new_node->height = node->height;
 250
 251        if (node->next)
 252                next_node = hfs_bnode_find(tree, node->next);
 253        else
 254                next_node = NULL;
 255
 256        if (IS_ERR(next_node)) {
 257                hfs_bnode_put(node);
 258                hfs_bnode_put(new_node);
 259                return next_node;
 260        }
 261
 262        size = tree->node_size / 2 - node->num_recs * 2 - 14;
 263        old_rec_off = tree->node_size - 4;
 264        num_recs = 1;
 265        for (;;) {
 266                data_start = hfs_bnode_read_u16(node, old_rec_off);
 267                if (data_start > size)
 268                        break;
 269                old_rec_off -= 2;
 270                if (++num_recs < node->num_recs)
 271                        continue;
 272                /* panic? */
 273                hfs_bnode_put(node);
 274                hfs_bnode_put(new_node);
 275                if (next_node)
 276                        hfs_bnode_put(next_node);
 277                return ERR_PTR(-ENOSPC);
 278        }
 279
 280        if (fd->record + 1 < num_recs) {
 281                /* new record is in the lower half,
 282                 * so leave some more space there
 283                 */
 284                old_rec_off += 2;
 285                num_recs--;
 286                data_start = hfs_bnode_read_u16(node, old_rec_off);
 287        } else {
 288                hfs_bnode_put(node);
 289                hfs_bnode_get(new_node);
 290                fd->bnode = new_node;
 291                fd->record -= num_recs;
 292                fd->keyoffset -= data_start - 14;
 293                fd->entryoffset -= data_start - 14;
 294        }
 295        new_node->num_recs = node->num_recs - num_recs;
 296        node->num_recs = num_recs;
 297
 298        new_rec_off = tree->node_size - 2;
 299        new_off = 14;
 300        size = data_start - new_off;
 301        num_recs = new_node->num_recs;
 302        data_end = data_start;
 303        while (num_recs) {
 304                hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 305                old_rec_off -= 2;
 306                new_rec_off -= 2;
 307                data_end = hfs_bnode_read_u16(node, old_rec_off);
 308                new_off = data_end - size;
 309                num_recs--;
 310        }
 311        hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 312        hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 313
 314        /* update new bnode header */
 315        node_desc.next = cpu_to_be32(new_node->next);
 316        node_desc.prev = cpu_to_be32(new_node->prev);
 317        node_desc.type = new_node->type;
 318        node_desc.height = new_node->height;
 319        node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 320        node_desc.reserved = 0;
 321        hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 322
 323        /* update previous bnode header */
 324        node->next = new_node->this;
 325        hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 326        node_desc.next = cpu_to_be32(node->next);
 327        node_desc.num_recs = cpu_to_be16(node->num_recs);
 328        hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 329
 330        /* update next bnode header */
 331        if (next_node) {
 332                next_node->prev = new_node->this;
 333                hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 334                node_desc.prev = cpu_to_be32(next_node->prev);
 335                hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 336                hfs_bnode_put(next_node);
 337        } else if (node->this == tree->leaf_tail) {
 338                /* if there is no next node, this might be the new tail */
 339                tree->leaf_tail = new_node->this;
 340                mark_inode_dirty(tree->inode);
 341        }
 342
 343        hfs_bnode_dump(node);
 344        hfs_bnode_dump(new_node);
 345        hfs_bnode_put(node);
 346
 347        return new_node;
 348}
 349
 350static int hfs_brec_update_parent(struct hfs_find_data *fd)
 351{
 352        struct hfs_btree *tree;
 353        struct hfs_bnode *node, *new_node, *parent;
 354        int newkeylen, diff;
 355        int rec, rec_off, end_rec_off;
 356        int start_off, end_off;
 357
 358        tree = fd->tree;
 359        node = fd->bnode;
 360        new_node = NULL;
 361        if (!node->parent)
 362                return 0;
 363
 364again:
 365        parent = hfs_bnode_find(tree, node->parent);
 366        if (IS_ERR(parent))
 367                return PTR_ERR(parent);
 368        __hfs_brec_find(parent, fd);
 369        hfs_bnode_dump(parent);
 370        rec = fd->record;
 371
 372        /* size difference between old and new key */
 373        if (tree->attributes & HFS_TREE_VARIDXKEYS)
 374                newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
 375        else
 376                fd->keylength = newkeylen = tree->max_key_len + 1;
 377        hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n",
 378                rec, fd->keylength, newkeylen);
 379
 380        rec_off = tree->node_size - (rec + 2) * 2;
 381        end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 382        diff = newkeylen - fd->keylength;
 383        if (!diff)
 384                goto skip;
 385        if (diff > 0) {
 386                end_off = hfs_bnode_read_u16(parent, end_rec_off);
 387                if (end_rec_off - end_off < diff) {
 388
 389                        printk(KERN_DEBUG "splitting index node...\n");
 390                        fd->bnode = parent;
 391                        new_node = hfs_bnode_split(fd);
 392                        if (IS_ERR(new_node))
 393                                return PTR_ERR(new_node);
 394                        parent = fd->bnode;
 395                        rec = fd->record;
 396                        rec_off = tree->node_size - (rec + 2) * 2;
 397                        end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 398                }
 399        }
 400
 401        end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 402        hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 403        start_off -= 4; /* move previous cnid too */
 404
 405        while (rec_off > end_rec_off) {
 406                rec_off -= 2;
 407                end_off = hfs_bnode_read_u16(parent, rec_off);
 408                hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 409        }
 410        hfs_bnode_move(parent, start_off + diff, start_off,
 411                       end_off - start_off);
 412skip:
 413        hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 414        if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
 415                hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
 416        hfs_bnode_dump(parent);
 417
 418        hfs_bnode_put(node);
 419        node = parent;
 420
 421        if (new_node) {
 422                __be32 cnid;
 423
 424                fd->bnode = hfs_bnode_find(tree, new_node->parent);
 425                /* create index key and entry */
 426                hfs_bnode_read_key(new_node, fd->search_key, 14);
 427                cnid = cpu_to_be32(new_node->this);
 428
 429                __hfs_brec_find(fd->bnode, fd);
 430                hfs_brec_insert(fd, &cnid, sizeof(cnid));
 431                hfs_bnode_put(fd->bnode);
 432                hfs_bnode_put(new_node);
 433
 434                if (!rec) {
 435                        if (new_node == node)
 436                                goto out;
 437                        /* restore search_key */
 438                        hfs_bnode_read_key(node, fd->search_key, 14);
 439                }
 440        }
 441
 442        if (!rec && node->parent)
 443                goto again;
 444out:
 445        fd->bnode = node;
 446        return 0;
 447}
 448
 449static int hfs_btree_inc_height(struct hfs_btree *tree)
 450{
 451        struct hfs_bnode *node, *new_node;
 452        struct hfs_bnode_desc node_desc;
 453        int key_size, rec;
 454        __be32 cnid;
 455
 456        node = NULL;
 457        if (tree->root) {
 458                node = hfs_bnode_find(tree, tree->root);
 459                if (IS_ERR(node))
 460                        return PTR_ERR(node);
 461        }
 462        new_node = hfs_bmap_alloc(tree);
 463        if (IS_ERR(new_node)) {
 464                hfs_bnode_put(node);
 465                return PTR_ERR(new_node);
 466        }
 467
 468        tree->root = new_node->this;
 469        if (!tree->depth) {
 470                tree->leaf_head = tree->leaf_tail = new_node->this;
 471                new_node->type = HFS_NODE_LEAF;
 472                new_node->num_recs = 0;
 473        } else {
 474                new_node->type = HFS_NODE_INDEX;
 475                new_node->num_recs = 1;
 476        }
 477        new_node->parent = 0;
 478        new_node->next = 0;
 479        new_node->prev = 0;
 480        new_node->height = ++tree->depth;
 481
 482        node_desc.next = cpu_to_be32(new_node->next);
 483        node_desc.prev = cpu_to_be32(new_node->prev);
 484        node_desc.type = new_node->type;
 485        node_desc.height = new_node->height;
 486        node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 487        node_desc.reserved = 0;
 488        hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 489
 490        rec = tree->node_size - 2;
 491        hfs_bnode_write_u16(new_node, rec, 14);
 492
 493        if (node) {
 494                /* insert old root idx into new root */
 495                node->parent = tree->root;
 496                if (node->type == HFS_NODE_LEAF ||
 497                    tree->attributes & HFS_TREE_VARIDXKEYS)
 498                        key_size = hfs_bnode_read_u8(node, 14) + 1;
 499                else
 500                        key_size = tree->max_key_len + 1;
 501                hfs_bnode_copy(new_node, 14, node, 14, key_size);
 502
 503                if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
 504                        key_size = tree->max_key_len + 1;
 505                        hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
 506                }
 507                key_size = (key_size + 1) & -2;
 508                cnid = cpu_to_be32(node->this);
 509                hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 510
 511                rec -= 2;
 512                hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 513
 514                hfs_bnode_put(node);
 515        }
 516        hfs_bnode_put(new_node);
 517        mark_inode_dirty(tree->inode);
 518
 519        return 0;
 520}
 521
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