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           (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        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, hfs_find_rec_by_key);
 156
 157                hfs_bnode_put(new_node);
 158                new_node = NULL;
 159
 160                if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
 161                                (tree->cnid == HFSPLUS_ATTR_CNID))
 162                        key_len = be16_to_cpu(fd->search_key->key_len) + 2;
 163                else {
 164                        fd->search_key->key_len =
 165                                cpu_to_be16(tree->max_key_len);
 166                        key_len = tree->max_key_len + 2;
 167                }
 168                goto again;
 169        }
 170
 171        if (!rec)
 172                hfs_brec_update_parent(fd);
 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        hfs_bnode_dump(parent);
 374        rec = fd->record;
 375
 376        /* size difference between old and new key */
 377        if ((tree->attributes & HFS_TREE_VARIDXKEYS) ||
 378                                (tree->cnid == HFSPLUS_ATTR_CNID))
 379                newkeylen = hfs_bnode_read_u16(node, 14) + 2;
 380        else
 381                fd->keylength = newkeylen = tree->max_key_len + 2;
 382        hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n",
 383                rec, fd->keylength, newkeylen);
 384
 385        rec_off = tree->node_size - (rec + 2) * 2;
 386        end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 387        diff = newkeylen - fd->keylength;
 388        if (!diff)
 389                goto skip;
 390        if (diff > 0) {
 391                end_off = hfs_bnode_read_u16(parent, end_rec_off);
 392                if (end_rec_off - end_off < diff) {
 393
 394                        hfs_dbg(BNODE_MOD, "splitting index node\n");
 395                        fd->bnode = parent;
 396                        new_node = hfs_bnode_split(fd);
 397                        if (IS_ERR(new_node))
 398                                return PTR_ERR(new_node);
 399                        parent = fd->bnode;
 400                        rec = fd->record;
 401                        rec_off = tree->node_size - (rec + 2) * 2;
 402                        end_rec_off = tree->node_size -
 403                                (parent->num_recs + 1) * 2;
 404                }
 405        }
 406
 407        end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 408        hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 409        start_off -= 4; /* move previous cnid too */
 410
 411        while (rec_off > end_rec_off) {
 412                rec_off -= 2;
 413                end_off = hfs_bnode_read_u16(parent, rec_off);
 414                hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 415        }
 416        hfs_bnode_move(parent, start_off + diff, start_off,
 417                       end_off - start_off);
 418skip:
 419        hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 420        hfs_bnode_dump(parent);
 421
 422        hfs_bnode_put(node);
 423        node = parent;
 424
 425        if (new_node) {
 426                __be32 cnid;
 427
 428                fd->bnode = hfs_bnode_find(tree, new_node->parent);
 429                /* create index key and entry */
 430                hfs_bnode_read_key(new_node, fd->search_key, 14);
 431                cnid = cpu_to_be32(new_node->this);
 432
 433                __hfs_brec_find(fd->bnode, fd, hfs_find_rec_by_key);
 434                hfs_brec_insert(fd, &cnid, sizeof(cnid));
 435                hfs_bnode_put(fd->bnode);
 436                hfs_bnode_put(new_node);
 437
 438                if (!rec) {
 439                        if (new_node == node)
 440                                goto out;
 441                        /* restore search_key */
 442                        hfs_bnode_read_key(node, fd->search_key, 14);
 443                }
 444        }
 445
 446        if (!rec && node->parent)
 447                goto again;
 448out:
 449        fd->bnode = node;
 450        return 0;
 451}
 452
 453static int hfs_btree_inc_height(struct hfs_btree *tree)
 454{
 455        struct hfs_bnode *node, *new_node;
 456        struct hfs_bnode_desc node_desc;
 457        int key_size, rec;
 458        __be32 cnid;
 459
 460        node = NULL;
 461        if (tree->root) {
 462                node = hfs_bnode_find(tree, tree->root);
 463                if (IS_ERR(node))
 464                        return PTR_ERR(node);
 465        }
 466        new_node = hfs_bmap_alloc(tree);
 467        if (IS_ERR(new_node)) {
 468                hfs_bnode_put(node);
 469                return PTR_ERR(new_node);
 470        }
 471
 472        tree->root = new_node->this;
 473        if (!tree->depth) {
 474                tree->leaf_head = tree->leaf_tail = new_node->this;
 475                new_node->type = HFS_NODE_LEAF;
 476                new_node->num_recs = 0;
 477        } else {
 478                new_node->type = HFS_NODE_INDEX;
 479                new_node->num_recs = 1;
 480        }
 481        new_node->parent = 0;
 482        new_node->next = 0;
 483        new_node->prev = 0;
 484        new_node->height = ++tree->depth;
 485
 486        node_desc.next = cpu_to_be32(new_node->next);
 487        node_desc.prev = cpu_to_be32(new_node->prev);
 488        node_desc.type = new_node->type;
 489        node_desc.height = new_node->height;
 490        node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 491        node_desc.reserved = 0;
 492        hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 493
 494        rec = tree->node_size - 2;
 495        hfs_bnode_write_u16(new_node, rec, 14);
 496
 497        if (node) {
 498                /* insert old root idx into new root */
 499                node->parent = tree->root;
 500                if (node->type == HFS_NODE_LEAF ||
 501                                tree->attributes & HFS_TREE_VARIDXKEYS ||
 502                                tree->cnid == HFSPLUS_ATTR_CNID)
 503                        key_size = hfs_bnode_read_u16(node, 14) + 2;
 504                else
 505                        key_size = tree->max_key_len + 2;
 506                hfs_bnode_copy(new_node, 14, node, 14, key_size);
 507
 508                if (!(tree->attributes & HFS_TREE_VARIDXKEYS) &&
 509                                (tree->cnid != HFSPLUS_ATTR_CNID)) {
 510                        key_size = tree->max_key_len + 2;
 511                        hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
 512                }
 513                cnid = cpu_to_be32(node->this);
 514                hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 515
 516                rec -= 2;
 517                hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 518
 519                hfs_bnode_put(node);
 520        }
 521        hfs_bnode_put(new_node);
 522        mark_inode_dirty(tree->inode);
 523
 524        return 0;
 525}
 526
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