linux/fs/hfsplus/brec.c
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   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                retval = node->tree->max_key_len + 2;
  41        } else {
  42                recoff = hfs_bnode_read_u16(node,
  43                        node->tree->node_size - (rec + 1) * 2);
  44                if (!recoff)
  45                        return 0;
  46                if (recoff > node->tree->node_size - 2) {
  47                        printk(KERN_ERR "hfs: recoff %d too large\n", recoff);
  48                        return 0;
  49                }
  50
  51                retval = hfs_bnode_read_u16(node, recoff) + 2;
  52                if (retval > node->tree->max_key_len + 2) {
  53                        printk(KERN_ERR "hfs: keylen %d too large\n",
  54                                retval);
  55                        retval = 0;
  56                }
  57        }
  58        return retval;
  59}
  60
  61int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  62{
  63        struct hfs_btree *tree;
  64        struct hfs_bnode *node, *new_node;
  65        int size, key_len, rec;
  66        int data_off, end_off;
  67        int idx_rec_off, data_rec_off, end_rec_off;
  68        __be32 cnid;
  69
  70        tree = fd->tree;
  71        if (!fd->bnode) {
  72                if (!tree->root)
  73                        hfs_btree_inc_height(tree);
  74                fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  75                if (IS_ERR(fd->bnode))
  76                        return PTR_ERR(fd->bnode);
  77                fd->record = -1;
  78        }
  79        new_node = NULL;
  80        key_len = be16_to_cpu(fd->search_key->key_len) + 2;
  81again:
  82        /* new record idx and complete record size */
  83        rec = fd->record + 1;
  84        size = key_len + entry_len;
  85
  86        node = fd->bnode;
  87        hfs_bnode_dump(node);
  88        /* get last offset */
  89        end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  90        end_off = hfs_bnode_read_u16(node, end_rec_off);
  91        end_rec_off -= 2;
  92        dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
  93                rec, size, end_off, end_rec_off);
  94        if (size > end_rec_off - end_off) {
  95                if (new_node)
  96                        panic("not enough room!\n");
  97                new_node = hfs_bnode_split(fd);
  98                if (IS_ERR(new_node))
  99                        return PTR_ERR(new_node);
 100                goto again;
 101        }
 102        if (node->type == HFS_NODE_LEAF) {
 103                tree->leaf_count++;
 104                mark_inode_dirty(tree->inode);
 105        }
 106        node->num_recs++;
 107        /* write new last offset */
 108        hfs_bnode_write_u16(node,
 109                offsetof(struct hfs_bnode_desc, num_recs),
 110                node->num_recs);
 111        hfs_bnode_write_u16(node, end_rec_off, end_off + size);
 112        data_off = end_off;
 113        data_rec_off = end_rec_off + 2;
 114        idx_rec_off = tree->node_size - (rec + 1) * 2;
 115        if (idx_rec_off == data_rec_off)
 116                goto skip;
 117        /* move all following entries */
 118        do {
 119                data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
 120                hfs_bnode_write_u16(node, data_rec_off, data_off + size);
 121                data_rec_off += 2;
 122        } while (data_rec_off < idx_rec_off);
 123
 124        /* move data away */
 125        hfs_bnode_move(node, data_off + size, data_off,
 126                       end_off - data_off);
 127
 128skip:
 129        hfs_bnode_write(node, fd->search_key, data_off, key_len);
 130        hfs_bnode_write(node, entry, data_off + key_len, entry_len);
 131        hfs_bnode_dump(node);
 132
 133        if (new_node) {
 134                /* update parent key if we inserted a key
 135                 * at the start of the first node
 136                 */
 137                if (!rec && new_node != node)
 138                        hfs_brec_update_parent(fd);
 139
 140                hfs_bnode_put(fd->bnode);
 141                if (!new_node->parent) {
 142                        hfs_btree_inc_height(tree);
 143                        new_node->parent = tree->root;
 144                }
 145                fd->bnode = hfs_bnode_find(tree, new_node->parent);
 146
 147                /* create index data entry */
 148                cnid = cpu_to_be32(new_node->this);
 149                entry = &cnid;
 150                entry_len = sizeof(cnid);
 151
 152                /* get index key */
 153                hfs_bnode_read_key(new_node, fd->search_key, 14);
 154                __hfs_brec_find(fd->bnode, fd);
 155
 156                hfs_bnode_put(new_node);
 157                new_node = NULL;
 158
 159                if (tree->attributes & HFS_TREE_VARIDXKEYS)
 160                        key_len = be16_to_cpu(fd->search_key->key_len) + 2;
 161                else {
 162                        fd->search_key->key_len =
 163                                cpu_to_be16(tree->max_key_len);
 164                        key_len = tree->max_key_len + 2;
 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        dprint(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,
 208                offsetof(struct hfs_bnode_desc, num_recs),
 209                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);
 224skip:
 225        hfs_bnode_dump(node);
 226        if (!fd->record)
 227                hfs_brec_update_parent(fd);
 228        return 0;
 229}
 230
 231static 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        dprint(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
 352static 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
 366again:
 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        hfs_bnode_dump(parent);
 372        rec = fd->record;
 373
 374        /* size difference between old and new key */
 375        if (tree->attributes & HFS_TREE_VARIDXKEYS)
 376                newkeylen = hfs_bnode_read_u16(node, 14) + 2;
 377        else
 378                fd->keylength = newkeylen = tree->max_key_len + 2;
 379        dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n",
 380                rec, fd->keylength, newkeylen);
 381
 382        rec_off = tree->node_size - (rec + 2) * 2;
 383        end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 384        diff = newkeylen - fd->keylength;
 385        if (!diff)
 386                goto skip;
 387        if (diff > 0) {
 388                end_off = hfs_bnode_read_u16(parent, end_rec_off);
 389                if (end_rec_off - end_off < diff) {
 390
 391                        dprint(DBG_BNODE_MOD, "hfs: splitting index node.\n");
 392                        fd->bnode = parent;
 393                        new_node = hfs_bnode_split(fd);
 394                        if (IS_ERR(new_node))
 395                                return PTR_ERR(new_node);
 396                        parent = fd->bnode;
 397                        rec = fd->record;
 398                        rec_off = tree->node_size - (rec + 2) * 2;
 399                        end_rec_off = tree->node_size -
 400                                (parent->num_recs + 1) * 2;
 401                }
 402        }
 403
 404        end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 405        hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 406        start_off -= 4; /* move previous cnid too */
 407
 408        while (rec_off > end_rec_off) {
 409                rec_off -= 2;
 410                end_off = hfs_bnode_read_u16(parent, rec_off);
 411                hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 412        }
 413        hfs_bnode_move(parent, start_off + diff, start_off,
 414                       end_off - start_off);
 415skip:
 416        hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 417        hfs_bnode_dump(parent);
 418
 419        hfs_bnode_put(node);
 420        node = parent;
 421
 422        if (new_node) {
 423                __be32 cnid;
 424
 425                fd->bnode = hfs_bnode_find(tree, new_node->parent);
 426                /* create index key and entry */
 427                hfs_bnode_read_key(new_node, fd->search_key, 14);
 428                cnid = cpu_to_be32(new_node->this);
 429
 430                __hfs_brec_find(fd->bnode, fd);
 431                hfs_brec_insert(fd, &cnid, sizeof(cnid));
 432                hfs_bnode_put(fd->bnode);
 433                hfs_bnode_put(new_node);
 434
 435                if (!rec) {
 436                        if (new_node == node)
 437                                goto out;
 438                        /* restore search_key */
 439                        hfs_bnode_read_key(node, fd->search_key, 14);
 440                }
 441        }
 442
 443        if (!rec && node->parent)
 444                goto again;
 445out:
 446        fd->bnode = node;
 447        return 0;
 448}
 449
 450static int hfs_btree_inc_height(struct hfs_btree *tree)
 451{
 452        struct hfs_bnode *node, *new_node;
 453        struct hfs_bnode_desc node_desc;
 454        int key_size, rec;
 455        __be32 cnid;
 456
 457        node = NULL;
 458        if (tree->root) {
 459                node = hfs_bnode_find(tree, tree->root);
 460                if (IS_ERR(node))
 461                        return PTR_ERR(node);
 462        }
 463        new_node = hfs_bmap_alloc(tree);
 464        if (IS_ERR(new_node)) {
 465                hfs_bnode_put(node);
 466                return PTR_ERR(new_node);
 467        }
 468
 469        tree->root = new_node->this;
 470        if (!tree->depth) {
 471                tree->leaf_head = tree->leaf_tail = new_node->this;
 472                new_node->type = HFS_NODE_LEAF;
 473                new_node->num_recs = 0;
 474        } else {
 475                new_node->type = HFS_NODE_INDEX;
 476                new_node->num_recs = 1;
 477        }
 478        new_node->parent = 0;
 479        new_node->next = 0;
 480        new_node->prev = 0;
 481        new_node->height = ++tree->depth;
 482
 483        node_desc.next = cpu_to_be32(new_node->next);
 484        node_desc.prev = cpu_to_be32(new_node->prev);
 485        node_desc.type = new_node->type;
 486        node_desc.height = new_node->height;
 487        node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 488        node_desc.reserved = 0;
 489        hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 490
 491        rec = tree->node_size - 2;
 492        hfs_bnode_write_u16(new_node, rec, 14);
 493
 494        if (node) {
 495                /* insert old root idx into new root */
 496                node->parent = tree->root;
 497                if (node->type == HFS_NODE_LEAF ||
 498                    tree->attributes & HFS_TREE_VARIDXKEYS)
 499                        key_size = hfs_bnode_read_u16(node, 14) + 2;
 500                else
 501                        key_size = tree->max_key_len + 2;
 502                hfs_bnode_copy(new_node, 14, node, 14, key_size);
 503
 504                if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
 505                        key_size = tree->max_key_len + 2;
 506                        hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
 507                }
 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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