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
  14 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
  15 static int hfs_brec_update_parent(struct hfs_find_data *fd);
  16 static int hfs_btree_inc_height(struct hfs_btree *);
  17
  18 /* Get the length and offset of the given record in the given node */
  19 u16 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 */
  31 u16 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
  61 int 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;
  81 again:
  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
 128 skip:
 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
 175 int 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;
 183 again:
 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);
 224 skip:
 225         hfs_bnode_dump(node);
 226         if (!fd->record)
 227                 hfs_brec_update_parent(fd);
 228         return 0;
 229 }
 230
 231 static 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
 352 static 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
 366 again:
 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);
 415 skip:
 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;
 445 out:
 446         fd->bnode = node;
 447         return 0;
 448 }
 449
 450 static 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 }