linux/fs/hfsplus/brec.c
<<
>>
Prefs
   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, node->tree->node_size - (rec + 1) * 2);
  43                if (!recoff)
  44                        return 0;
  45                if (node->tree->attributes & HFS_TREE_BIGKEYS)
  46                        retval = hfs_bnode_read_u16(node, recoff) + 2;
  47                else
  48                        retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
  49        }
  50        return retval;
  51}
  52
  53int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  54{
  55        struct hfs_btree *tree;
  56        struct hfs_bnode *node, *new_node;
  57        int size, key_len, rec;
  58        int data_off, end_off;
  59        int idx_rec_off, data_rec_off, end_rec_off;
  60        __be32 cnid;
  61
  62        tree = fd->tree;
  63        if (!fd->bnode) {
  64                if (!tree->root)
  65                        hfs_btree_inc_height(tree);
  66                fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  67                if (IS_ERR(fd->bnode))
  68                        return PTR_ERR(fd->bnode);
  69                fd->record = -1;
  70        }
  71        new_node = NULL;
  72        key_len = be16_to_cpu(fd->search_key->key_len) + 2;
  73again:
  74        /* new record idx and complete record size */
  75        rec = fd->record + 1;
  76        size = key_len + entry_len;
  77
  78        node = fd->bnode;
  79        hfs_bnode_dump(node);
  80        /* get last offset */
  81        end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  82        end_off = hfs_bnode_read_u16(node, end_rec_off);
  83        end_rec_off -= 2;
  84        dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
  85        if (size > end_rec_off - end_off) {
  86                if (new_node)
  87                        panic("not enough room!\n");
  88                new_node = hfs_bnode_split(fd);
  89                if (IS_ERR(new_node))
  90                        return PTR_ERR(new_node);
  91                goto again;
  92        }
  93        if (node->type == HFS_NODE_LEAF) {
  94                tree->leaf_count++;
  95                mark_inode_dirty(tree->inode);
  96        }
  97        node->num_recs++;
  98        /* write new last offset */
  99        hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 100        hfs_bnode_write_u16(node, end_rec_off, end_off + size);
 101        data_off = end_off;
 102        data_rec_off = end_rec_off + 2;
 103        idx_rec_off = tree->node_size - (rec + 1) * 2;
 104        if (idx_rec_off == data_rec_off)
 105                goto skip;
 106        /* move all following entries */
 107        do {
 108                data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
 109                hfs_bnode_write_u16(node, data_rec_off, data_off + size);
 110                data_rec_off += 2;
 111        } while (data_rec_off < idx_rec_off);
 112
 113        /* move data away */
 114        hfs_bnode_move(node, data_off + size, data_off,
 115                       end_off - data_off);
 116
 117skip:
 118        hfs_bnode_write(node, fd->search_key, data_off, key_len);
 119        hfs_bnode_write(node, entry, data_off + key_len, entry_len);
 120        hfs_bnode_dump(node);
 121
 122        if (new_node) {
 123                /* update parent key if we inserted a key
 124                 * at the start of the first node
 125                 */
 126                if (!rec && new_node != node)
 127                        hfs_brec_update_parent(fd);
 128
 129                hfs_bnode_put(fd->bnode);
 130                if (!new_node->parent) {
 131                        hfs_btree_inc_height(tree);
 132                        new_node->parent = tree->root;
 133                }
 134                fd->bnode = hfs_bnode_find(tree, new_node->parent);
 135
 136                /* create index data entry */
 137                cnid = cpu_to_be32(new_node->this);
 138                entry = &cnid;
 139                entry_len = sizeof(cnid);
 140
 141                /* get index key */
 142                hfs_bnode_read_key(new_node, fd->search_key, 14);
 143                __hfs_brec_find(fd->bnode, fd);
 144
 145                hfs_bnode_put(new_node);
 146                new_node = NULL;
 147
 148                if (tree->attributes & HFS_TREE_VARIDXKEYS)
 149                        key_len = be16_to_cpu(fd->search_key->key_len) + 2;
 150                else {
 151                        fd->search_key->key_len = cpu_to_be16(tree->max_key_len);
 152                        key_len = tree->max_key_len + 2;
 153                }
 154                goto again;
 155        }
 156
 157        if (!rec)
 158                hfs_brec_update_parent(fd);
 159
 160        return 0;
 161}
 162
 163int hfs_brec_remove(struct hfs_find_data *fd)
 164{
 165        struct hfs_btree *tree;
 166        struct hfs_bnode *node, *parent;
 167        int end_off, rec_off, data_off, size;
 168
 169        tree = fd->tree;
 170        node = fd->bnode;
 171again:
 172        rec_off = tree->node_size - (fd->record + 2) * 2;
 173        end_off = tree->node_size - (node->num_recs + 1) * 2;
 174
 175        if (node->type == HFS_NODE_LEAF) {
 176                tree->leaf_count--;
 177                mark_inode_dirty(tree->inode);
 178        }
 179        hfs_bnode_dump(node);
 180        dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", fd->record, fd->keylength + fd->entrylength);
 181        if (!--node->num_recs) {
 182                hfs_bnode_unlink(node);
 183                if (!node->parent)
 184                        return 0;
 185                parent = hfs_bnode_find(tree, node->parent);
 186                if (IS_ERR(parent))
 187                        return PTR_ERR(parent);
 188                hfs_bnode_put(node);
 189                node = fd->bnode = parent;
 190
 191                __hfs_brec_find(node, fd);
 192                goto again;
 193        }
 194        hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 195
 196        if (rec_off == end_off)
 197                goto skip;
 198        size = fd->keylength + fd->entrylength;
 199
 200        do {
 201                data_off = hfs_bnode_read_u16(node, rec_off);
 202                hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
 203                rec_off -= 2;
 204        } while (rec_off >= end_off);
 205
 206        /* fill hole */
 207        hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
 208                       data_off - fd->keyoffset - size);
 209skip:
 210        hfs_bnode_dump(node);
 211        if (!fd->record)
 212                hfs_brec_update_parent(fd);
 213        return 0;
 214}
 215
 216static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
 217{
 218        struct hfs_btree *tree;
 219        struct hfs_bnode *node, *new_node;
 220        struct hfs_bnode_desc node_desc;
 221        int num_recs, new_rec_off, new_off, old_rec_off;
 222        int data_start, data_end, size;
 223
 224        tree = fd->tree;
 225        node = fd->bnode;
 226        new_node = hfs_bmap_alloc(tree);
 227        if (IS_ERR(new_node))
 228                return new_node;
 229        hfs_bnode_get(node);
 230        dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
 231                node->this, new_node->this, node->next);
 232        new_node->next = node->next;
 233        new_node->prev = node->this;
 234        new_node->parent = node->parent;
 235        new_node->type = node->type;
 236        new_node->height = node->height;
 237
 238        size = tree->node_size / 2 - node->num_recs * 2 - 14;
 239        old_rec_off = tree->node_size - 4;
 240        num_recs = 1;
 241        for (;;) {
 242                data_start = hfs_bnode_read_u16(node, old_rec_off);
 243                if (data_start > size)
 244                        break;
 245                old_rec_off -= 2;
 246                if (++num_recs < node->num_recs)
 247                        continue;
 248                /* panic? */
 249                hfs_bnode_put(node);
 250                hfs_bnode_put(new_node);
 251                return ERR_PTR(-ENOSPC);
 252        }
 253
 254        if (fd->record + 1 < num_recs) {
 255                /* new record is in the lower half,
 256                 * so leave some more space there
 257                 */
 258                old_rec_off += 2;
 259                num_recs--;
 260                data_start = hfs_bnode_read_u16(node, old_rec_off);
 261        } else {
 262                hfs_bnode_put(node);
 263                hfs_bnode_get(new_node);
 264                fd->bnode = new_node;
 265                fd->record -= num_recs;
 266                fd->keyoffset -= data_start - 14;
 267                fd->entryoffset -= data_start - 14;
 268        }
 269        new_node->num_recs = node->num_recs - num_recs;
 270        node->num_recs = num_recs;
 271
 272        new_rec_off = tree->node_size - 2;
 273        new_off = 14;
 274        size = data_start - new_off;
 275        num_recs = new_node->num_recs;
 276        data_end = data_start;
 277        while (num_recs) {
 278                hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 279                old_rec_off -= 2;
 280                new_rec_off -= 2;
 281                data_end = hfs_bnode_read_u16(node, old_rec_off);
 282                new_off = data_end - size;
 283                num_recs--;
 284        }
 285        hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 286        hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 287
 288        /* update new bnode header */
 289        node_desc.next = cpu_to_be32(new_node->next);
 290        node_desc.prev = cpu_to_be32(new_node->prev);
 291        node_desc.type = new_node->type;
 292        node_desc.height = new_node->height;
 293        node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 294        node_desc.reserved = 0;
 295        hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 296
 297        /* update previous bnode header */
 298        node->next = new_node->this;
 299        hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 300        node_desc.next = cpu_to_be32(node->next);
 301        node_desc.num_recs = cpu_to_be16(node->num_recs);
 302        hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 303
 304        /* update next bnode header */
 305        if (new_node->next) {
 306                struct hfs_bnode *next_node = hfs_bnode_find(tree, new_node->next);
 307                next_node->prev = new_node->this;
 308                hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 309                node_desc.prev = cpu_to_be32(next_node->prev);
 310                hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 311                hfs_bnode_put(next_node);
 312        } else if (node->this == tree->leaf_tail) {
 313                /* if there is no next node, this might be the new tail */
 314                tree->leaf_tail = new_node->this;
 315                mark_inode_dirty(tree->inode);
 316        }
 317
 318        hfs_bnode_dump(node);
 319        hfs_bnode_dump(new_node);
 320        hfs_bnode_put(node);
 321
 322        return new_node;
 323}
 324
 325static int hfs_brec_update_parent(struct hfs_find_data *fd)
 326{
 327        struct hfs_btree *tree;
 328        struct hfs_bnode *node, *new_node, *parent;
 329        int newkeylen, diff;
 330        int rec, rec_off, end_rec_off;
 331        int start_off, end_off;
 332
 333        tree = fd->tree;
 334        node = fd->bnode;
 335        new_node = NULL;
 336        if (!node->parent)
 337                return 0;
 338
 339again:
 340        parent = hfs_bnode_find(tree, node->parent);
 341        if (IS_ERR(parent))
 342                return PTR_ERR(parent);
 343        __hfs_brec_find(parent, fd);
 344        hfs_bnode_dump(parent);
 345        rec = fd->record;
 346
 347        /* size difference between old and new key */
 348        if (tree->attributes & HFS_TREE_VARIDXKEYS)
 349                newkeylen = hfs_bnode_read_u16(node, 14) + 2;
 350        else
 351                fd->keylength = newkeylen = tree->max_key_len + 2;
 352        dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
 353
 354        rec_off = tree->node_size - (rec + 2) * 2;
 355        end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 356        diff = newkeylen - fd->keylength;
 357        if (!diff)
 358                goto skip;
 359        if (diff > 0) {
 360                end_off = hfs_bnode_read_u16(parent, end_rec_off);
 361                if (end_rec_off - end_off < diff) {
 362
 363                        printk(KERN_DEBUG "hfs: splitting index node...\n");
 364                        fd->bnode = parent;
 365                        new_node = hfs_bnode_split(fd);
 366                        if (IS_ERR(new_node))
 367                                return PTR_ERR(new_node);
 368                        parent = fd->bnode;
 369                        rec = fd->record;
 370                        rec_off = tree->node_size - (rec + 2) * 2;
 371                        end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 372                }
 373        }
 374
 375        end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 376        hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 377        start_off -= 4; /* move previous cnid too */
 378
 379        while (rec_off > end_rec_off) {
 380                rec_off -= 2;
 381                end_off = hfs_bnode_read_u16(parent, rec_off);
 382                hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 383        }
 384        hfs_bnode_move(parent, start_off + diff, start_off,
 385                       end_off - start_off);
 386skip:
 387        hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 388        hfs_bnode_dump(parent);
 389
 390        hfs_bnode_put(node);
 391        node = parent;
 392
 393        if (new_node) {
 394                __be32 cnid;
 395
 396                fd->bnode = hfs_bnode_find(tree, new_node->parent);
 397                /* create index key and entry */
 398                hfs_bnode_read_key(new_node, fd->search_key, 14);
 399                cnid = cpu_to_be32(new_node->this);
 400
 401                __hfs_brec_find(fd->bnode, fd);
 402                hfs_brec_insert(fd, &cnid, sizeof(cnid));
 403                hfs_bnode_put(fd->bnode);
 404                hfs_bnode_put(new_node);
 405
 406                if (!rec) {
 407                        if (new_node == node)
 408                                goto out;
 409                        /* restore search_key */
 410                        hfs_bnode_read_key(node, fd->search_key, 14);
 411                }
 412        }
 413
 414        if (!rec && node->parent)
 415                goto again;
 416out:
 417        fd->bnode = node;
 418        return 0;
 419}
 420
 421static int hfs_btree_inc_height(struct hfs_btree *tree)
 422{
 423        struct hfs_bnode *node, *new_node;
 424        struct hfs_bnode_desc node_desc;
 425        int key_size, rec;
 426        __be32 cnid;
 427
 428        node = NULL;
 429        if (tree->root) {
 430                node = hfs_bnode_find(tree, tree->root);
 431                if (IS_ERR(node))
 432                        return PTR_ERR(node);
 433        }
 434        new_node = hfs_bmap_alloc(tree);
 435        if (IS_ERR(new_node)) {
 436                hfs_bnode_put(node);
 437                return PTR_ERR(new_node);
 438        }
 439
 440        tree->root = new_node->this;
 441        if (!tree->depth) {
 442                tree->leaf_head = tree->leaf_tail = new_node->this;
 443                new_node->type = HFS_NODE_LEAF;
 444                new_node->num_recs = 0;
 445        } else {
 446                new_node->type = HFS_NODE_INDEX;
 447                new_node->num_recs = 1;
 448        }
 449        new_node->parent = 0;
 450        new_node->next = 0;
 451        new_node->prev = 0;
 452        new_node->height = ++tree->depth;
 453
 454        node_desc.next = cpu_to_be32(new_node->next);
 455        node_desc.prev = cpu_to_be32(new_node->prev);
 456        node_desc.type = new_node->type;
 457        node_desc.height = new_node->height;
 458        node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 459        node_desc.reserved = 0;
 460        hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 461
 462        rec = tree->node_size - 2;
 463        hfs_bnode_write_u16(new_node, rec, 14);
 464
 465        if (node) {
 466                /* insert old root idx into new root */
 467                node->parent = tree->root;
 468                if (node->type == HFS_NODE_LEAF ||
 469                    tree->attributes & HFS_TREE_VARIDXKEYS)
 470                        key_size = hfs_bnode_read_u16(node, 14) + 2;
 471                else
 472                        key_size = tree->max_key_len + 2;
 473                hfs_bnode_copy(new_node, 14, node, 14, key_size);
 474
 475                if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
 476                        key_size = tree->max_key_len + 2;
 477                        hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
 478                }
 479                cnid = cpu_to_be32(node->this);
 480                hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 481
 482                rec -= 2;
 483                hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 484
 485                hfs_bnode_put(node);
 486        }
 487        hfs_bnode_put(new_node);
 488        mark_inode_dirty(tree->inode);
 489
 490        return 0;
 491}
 492
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.