LXR linux/fs/hfsplus/brec.c

   1/*
   2 *  linux/fs/hfsplus/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 "hfsplus_fs.h"
  12#include "hfsplus_raw.h"
  13
  14static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
  15static int hfs_brec_update_parent(struct hfs_find_data *fd);
  16static int hfs_btree_inc_height(struct hfs_btree *);
  17
  18/* Get the length and offset of the given record in the given node */
  19u16 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 */
  31u16 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           (node->tree->cnid != HFSPLUS_ATTR_CNID)) {
  41                retval = node->tree->max_key_len + 2;
  42        } else {
  43                recoff = hfs_bnode_read_u16(node,
  44                        node->tree->node_size - (rec + 1) * 2);
  45                if (!recoff)
  46                        return 0;
  47                if (recoff > node->tree->node_size - 2) {
  48                        pr_err("recoff %d too large\n", recoff);
  49                        return 0;
  50                }
  51
  52                retval = hfs_bnode_read_u16(node, recoff) + 2;
  53                if (retval > node->tree->max_key_len + 2) {
  54                        pr_err("keylen %d too large\n",
  55                                retval);
  56                        retval = 0;
  57                }
  58        }
  59        return retval;
  60}
  61
  62int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  63{
  64        struct hfs_btree *tree;
  65        struct hfs_bnode *node, *new_node;
  66        int size, key_len, rec;
  67        int data_off, end_off;
  68        int idx_rec_off, data_rec_off, end_rec_off;
  69        __be32 cnid;
  70
  71        tree = fd->tree;
  72        if (!fd->bnode) {
  73                if (!tree->root)
  74                        hfs_btree_inc_height(tree);
  75                fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  76                if (IS_ERR(fd->bnode))
  77                        return PTR_ERR(fd->bnode);
  78                fd->record = -1;
  79        }
  80        new_node = NULL;
  81        key_len = be16_to_cpu(fd->search_key->key_len) + 2;
  82again:
  83        /* new record idx and complete record size */
  84        rec = fd->record + 1;
  85        size = key_len + entry_len;
  86
  87        node = fd->bnode;
  88        hfs_bnode_dump(node);
  89        /* get last offset */
  90        end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  91        end_off = hfs_bnode_read_u16(node, end_rec_off);
  92        end_rec_off -= 2;
  93        hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
  94                rec, size, end_off, end_rec_off);
  95        if (size > end_rec_off - end_off) {
  96                if (new_node)
  97                        panic("not enough room!\n");
  98                new_node = hfs_bnode_split(fd);
  99                if (IS_ERR(new_node))
 100                        return PTR_ERR(new_node);
 101                goto again;
 102        }
 103        if (node->type == HFS_NODE_LEAF) {
 104                tree->leaf_count++;
 105                mark_inode_dirty(tree->inode);
 106        }
 107        node->num_recs++;
 108        /* write new last offset */
 109        hfs_bnode_write_u16(node,
 110                offsetof(struct hfs_bnode_desc, num_recs),
 111                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        /*
 135         * update parent key if we inserted a key
 136         * at the start of the node and it is not the new node
 137         */
 138        if (!rec && new_node != node) {
 139                hfs_bnode_read_key(node, fd->search_key, data_off + size);
 140                hfs_brec_update_parent(fd);
 141        }
 142
 143        if (new_node) {
 144                hfs_bnode_put(fd->bnode);
 145                if (!new_node->parent) {
 146                        hfs_btree_inc_height(tree);
 147                        new_node->parent = tree->root;
 148                }
 149                fd->bnode = hfs_bnode_find(tree, new_node->parent);
 150
 151                /* create index data entry */
 152                cnid = cpu_to_be32(new_node->this);
 153                entry = &cnid;
 154                entry_len = sizeof(cnid);
 155
 156                /* get index key */
 157                hfs_bnode_read_key(new_node, fd->search_key, 14);
 158                __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key);
 159
 160                hfs_bnode_put(new_node);
 161                new_node = NULL;
 162
 163                if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
 164                                (tree->cnid == HFSPLUS_ATTR_CNID))
 165                        key_len = be16_to_cpu(fd->search_key->key_len) + 2;
 166                else {
 167                        fd->search_key->key_len =
 168                                cpu_to_be16(tree->max_key_len);
 169                        key_len = tree->max_key_len + 2;
 170                }
 171                goto again;
 172        }
 173
 174        return 0;
 175}
 176
 177int 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;
 185again:
 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, hfs_find_rec_by_key);
 207                goto again;
 208        }
 209        hfs_bnode_write_u16(node,
 210                offsetof(struct hfs_bnode_desc, num_recs),
 211                node->num_recs);
 212
 213        if (rec_off == end_off)
 214                goto skip;
 215        size = fd->keylength + fd->entrylength;
 216
 217        do {
 218                data_off = hfs_bnode_read_u16(node, rec_off);
 219                hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
 220                rec_off -= 2;
 221        } while (rec_off >= end_off);
 222
 223        /* fill hole */
 224        hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
 225                       data_off - fd->keyoffset - size);
 226skip:
 227        hfs_bnode_dump(node);
 228        if (!fd->record)
 229                hfs_brec_update_parent(fd);
 230        return 0;
 231}
 232
 233static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
 234{
 235        struct hfs_btree *tree;
 236        struct hfs_bnode *node, *new_node, *next_node;
 237        struct hfs_bnode_desc node_desc;
 238        int num_recs, new_rec_off, new_off, old_rec_off;
 239        int data_start, data_end, size;
 240
 241        tree = fd->tree;
 242        node = fd->bnode;
 243        new_node = hfs_bmap_alloc(tree);
 244        if (IS_ERR(new_node))
 245                return new_node;
 246        hfs_bnode_get(node);
 247        hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n",
 248                node->this, new_node->this, node->next);
 249        new_node->next = node->next;
 250        new_node->prev = node->this;
 251        new_node->parent = node->parent;
 252        new_node->type = node->type;
 253        new_node->height = node->height;
 254
 255        if (node->next)
 256                next_node = hfs_bnode_find(tree, node->next);
 257        else
 258                next_node = NULL;
 259
 260        if (IS_ERR(next_node)) {
 261                hfs_bnode_put(node);
 262                hfs_bnode_put(new_node);
 263                return next_node;
 264        }
 265
 266        size = tree->node_size / 2 - node->num_recs * 2 - 14;
 267        old_rec_off = tree->node_size - 4;
 268        num_recs = 1;
 269        for (;;) {
 270                data_start = hfs_bnode_read_u16(node, old_rec_off);
 271                if (data_start > size)
 272                        break;
 273                old_rec_off -= 2;
 274                if (++num_recs < node->num_recs)
 275                        continue;
 276                /* panic? */
 277                hfs_bnode_put(node);
 278                hfs_bnode_put(new_node);
 279                if (next_node)
 280                        hfs_bnode_put(next_node);
 281                return ERR_PTR(-ENOSPC);
 282        }
 283
 284        if (fd->record + 1 < num_recs) {
 285                /* new record is in the lower half,
 286                 * so leave some more space there
 287                 */
 288                old_rec_off += 2;
 289                num_recs--;
 290                data_start = hfs_bnode_read_u16(node, old_rec_off);
 291        } else {
 292                hfs_bnode_put(node);
 293                hfs_bnode_get(new_node);
 294                fd->bnode = new_node;
 295                fd->record -= num_recs;
 296                fd->keyoffset -= data_start - 14;
 297                fd->entryoffset -= data_start - 14;
 298        }
 299        new_node->num_recs = node->num_recs - num_recs;
 300        node->num_recs = num_recs;
 301
 302        new_rec_off = tree->node_size - 2;
 303        new_off = 14;
 304        size = data_start - new_off;
 305        num_recs = new_node->num_recs;
 306        data_end = data_start;
 307        while (num_recs) {
 308                hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 309                old_rec_off -= 2;
 310                new_rec_off -= 2;
 311                data_end = hfs_bnode_read_u16(node, old_rec_off);
 312                new_off = data_end - size;
 313                num_recs--;
 314        }
 315        hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 316        hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 317
 318        /* update new bnode header */
 319        node_desc.next = cpu_to_be32(new_node->next);
 320        node_desc.prev = cpu_to_be32(new_node->prev);
 321        node_desc.type = new_node->type;
 322        node_desc.height = new_node->height;
 323        node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 324        node_desc.reserved = 0;
 325        hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 326
 327        /* update previous bnode header */
 328        node->next = new_node->this;
 329        hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 330        node_desc.next = cpu_to_be32(node->next);
 331        node_desc.num_recs = cpu_to_be16(node->num_recs);
 332        hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 333
 334        /* update next bnode header */
 335        if (next_node) {
 336                next_node->prev = new_node->this;
 337                hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 338                node_desc.prev = cpu_to_be32(next_node->prev);
 339                hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 340                hfs_bnode_put(next_node);
 341        } else if (node->this == tree->leaf_tail) {
 342                /* if there is no next node, this might be the new tail */
 343                tree->leaf_tail = new_node->this;
 344                mark_inode_dirty(tree->inode);
 345        }
 346
 347        hfs_bnode_dump(node);
 348        hfs_bnode_dump(new_node);
 349        hfs_bnode_put(node);
 350
 351        return new_node;
 352}
 353
 354static int hfs_brec_update_parent(struct hfs_find_data *fd)
 355{
 356        struct hfs_btree *tree;
 357        struct hfs_bnode *node, *new_node, *parent;
 358        int newkeylen, diff;
 359        int rec, rec_off, end_rec_off;
 360        int start_off, end_off;
 361
 362        tree = fd->tree;
 363        node = fd->bnode;
 364        new_node = NULL;
 365        if (!node->parent)
 366                return 0;
 367
 368again:
 369        parent = hfs_bnode_find(tree, node->parent);
 370        if (IS_ERR(parent))
 371                return PTR_ERR(parent);
 372        __hfs_brec_find(parent, fd, hfs_find_rec_by_key);
 373        if (fd->record < 0)
 374                return -ENOENT;
 375        hfs_bnode_dump(parent);
 376        rec = fd->record;
 377
 378        /* size difference between old and new key */
 379        if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
 380                                (tree->cnid == HFSPLUS_ATTR_CNID))
 381                newkeylen = hfs_bnode_read_u16(node, 14) + 2;
 382        else
 383                fd->keylength = newkeylen = tree->max_key_len + 2;
 384        hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n",
 385                rec, fd->keylength, newkeylen);
 386
 387        rec_off = tree->node_size - (rec + 2) * 2;
 388        end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 389        diff = newkeylen - fd->keylength;
 390        if (!diff)
 391                goto skip;
 392        if (diff > 0) {
 393                end_off = hfs_bnode_read_u16(parent, end_rec_off);
 394                if (end_rec_off - end_off < diff) {
 395
 396                        hfs_dbg(BNODE_MOD, "splitting index node\n");
 397                        fd->bnode = parent;
 398                        new_node = hfs_bnode_split(fd);
 399                        if (IS_ERR(new_node))
 400                                return PTR_ERR(new_node);
 401                        parent = fd->bnode;
 402                        rec = fd->record;
 403                        rec_off = tree->node_size - (rec + 2) * 2;
 404                        end_rec_off = tree->node_size -
 405                                (parent->num_recs + 1) * 2;
 406                }
 407        }
 408
 409        end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 410        hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 411        start_off -= 4; /* move previous cnid too */
 412
 413        while (rec_off > end_rec_off) {
 414                rec_off -= 2;
 415                end_off = hfs_bnode_read_u16(parent, rec_off);
 416                hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 417        }
 418        hfs_bnode_move(parent, start_off + diff, start_off,
 419                       end_off - start_off);
 420skip:
 421        hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 422        hfs_bnode_dump(parent);
 423
 424        hfs_bnode_put(node);
 425        node = parent;
 426
 427        if (new_node) {
 428                __be32 cnid;
 429
 430                fd->bnode = hfs_bnode_find(tree, new_node->parent);
 431                /* create index key and entry */
 432                hfs_bnode_read_key(new_node, fd->search_key, 14);
 433                cnid = cpu_to_be32(new_node->this);
 434
 435                __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key);
 436                hfs_brec_insert(fd, &cnid, sizeof(cnid));
 437                hfs_bnode_put(fd->bnode);
 438                hfs_bnode_put(new_node);
 439
 440                if (!rec) {
 441                        if (new_node == node)
 442                                goto out;
 443                        /* restore search_key */
 444                        hfs_bnode_read_key(node, fd->search_key, 14);
 445                }
 446        }
 447
 448        if (!rec && node->parent)
 449                goto again;
 450out:
 451        fd->bnode = node;
 452        return 0;
 453}
 454
 455static int hfs_btree_inc_height(struct hfs_btree *tree)
 456{
 457        struct hfs_bnode *node, *new_node;
 458        struct hfs_bnode_desc node_desc;
 459        int key_size, rec;
 460        __be32 cnid;
 461
 462        node = NULL;
 463        if (tree->root) {
 464                node = hfs_bnode_find(tree, tree->root);
 465                if (IS_ERR(node))
 466                        return PTR_ERR(node);
 467        }
 468        new_node = hfs_bmap_alloc(tree);
 469        if (IS_ERR(new_node)) {
 470                hfs_bnode_put(node);
 471                return PTR_ERR(new_node);
 472        }
 473
 474        tree->root = new_node->this;
 475        if (!tree->depth) {
 476                tree->leaf_head = tree->leaf_tail = new_node->this;
 477                new_node->type = HFS_NODE_LEAF;
 478                new_node->num_recs = 0;
 479        } else {
 480                new_node->type = HFS_NODE_INDEX;
 481                new_node->num_recs = 1;
 482        }
 483        new_node->parent = 0;
 484        new_node->next = 0;
 485        new_node->prev = 0;
 486        new_node->height = ++tree->depth;
 487
 488        node_desc.next = cpu_to_be32(new_node->next);
 489        node_desc.prev = cpu_to_be32(new_node->prev);
 490        node_desc.type = new_node->type;
 491        node_desc.height = new_node->height;
 492        node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 493        node_desc.reserved = 0;
 494        hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 495
 496        rec = tree->node_size - 2;
 497        hfs_bnode_write_u16(new_node, rec, 14);
 498
 499        if (node) {
 500                /* insert old root idx into new root */
 501                node->parent = tree->root;
 502                if (node->type == HFS_NODE_LEAF ||
 503                                tree->attributes & HFS_TREE_VARIDXKEYS ||
 504                                tree->cnid == HFSPLUS_ATTR_CNID)
 505                        key_size = hfs_bnode_read_u16(node, 14) + 2;
 506                else
 507                        key_size = tree->max_key_len + 2;
 508                hfs_bnode_copy(new_node, 14, node, 14, key_size);
 509
 510                if (!(tree->attributes & HFS_TREE_VARIDXKEYS) &&
 511                                (tree->cnid != HFSPLUS_ATTR_CNID)) {
 512                        key_size = tree->max_key_len + 2;
 513                        hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
 514                }
 515                cnid = cpu_to_be32(node->this);
 516                hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 517
 518                rec -= 2;
 519                hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 520
 521                hfs_bnode_put(node);
 522        }
 523        hfs_bnode_put(new_node);
 524        mark_inode_dirty(tree->inode);
 525
 526        return 0;
 527}
 528