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            (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
  62 int 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;
  82 again:
  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
 129 skip:
 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
 177 int 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;
 185 again:
 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);
 226 skip:
 227         hfs_bnode_dump(node);
 228         if (!fd->record)
 229                 hfs_brec_update_parent(fd);
 230         return 0;
 231 }
 232
 233 static 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
 354 static 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
 368 again:
 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);
 420 skip:
 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;
 450 out:
 451         fd->bnode = node;
 452         return 0;
 453 }
 454
 455 static 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 }