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
  47                 retval = hfs_bnode_read_u16(node, recoff) + 2;
  48                 if (retval > node->tree->max_key_len + 2) {
  49                         printk(KERN_ERR "hfs: keylen %d too large\n",
  50                                 retval);
  51                         retval = 0;
  52                 }
  53         }
  54         return retval;
  55 }
  56
  57 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  58 {
  59         struct hfs_btree *tree;
  60         struct hfs_bnode *node, *new_node;
  61         int size, key_len, rec;
  62         int data_off, end_off;
  63         int idx_rec_off, data_rec_off, end_rec_off;
  64         __be32 cnid;
  65
  66         tree = fd->tree;
  67         if (!fd->bnode) {
  68                 if (!tree->root)
  69                         hfs_btree_inc_height(tree);
  70                 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  71                 if (IS_ERR(fd->bnode))
  72                         return PTR_ERR(fd->bnode);
  73                 fd->record = -1;
  74         }
  75         new_node = NULL;
  76         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
  77 again:
  78         /* new record idx and complete record size */
  79         rec = fd->record + 1;
  80         size = key_len + entry_len;
  81
  82         node = fd->bnode;
  83         hfs_bnode_dump(node);
  84         /* get last offset */
  85         end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  86         end_off = hfs_bnode_read_u16(node, end_rec_off);
  87         end_rec_off -= 2;
  88         dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
  89                 rec, size, end_off, end_rec_off);
  90         if (size > end_rec_off - end_off) {
  91                 if (new_node)
  92                         panic("not enough room!\n");
  93                 new_node = hfs_bnode_split(fd);
  94                 if (IS_ERR(new_node))
  95                         return PTR_ERR(new_node);
  96                 goto again;
  97         }
  98         if (node->type == HFS_NODE_LEAF) {
  99                 tree->leaf_count++;
 100                 mark_inode_dirty(tree->inode);
 101         }
 102         node->num_recs++;
 103         /* write new last offset */
 104         hfs_bnode_write_u16(node,
 105                 offsetof(struct hfs_bnode_desc, num_recs),
 106                 node->num_recs);
 107         hfs_bnode_write_u16(node, end_rec_off, end_off + size);
 108         data_off = end_off;
 109         data_rec_off = end_rec_off + 2;
 110         idx_rec_off = tree->node_size - (rec + 1) * 2;
 111         if (idx_rec_off == data_rec_off)
 112                 goto skip;
 113         /* move all following entries */
 114         do {
 115                 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
 116                 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
 117                 data_rec_off += 2;
 118         } while (data_rec_off < idx_rec_off);
 119
 120         /* move data away */
 121         hfs_bnode_move(node, data_off + size, data_off,
 122                        end_off - data_off);
 123
 124 skip:
 125         hfs_bnode_write(node, fd->search_key, data_off, key_len);
 126         hfs_bnode_write(node, entry, data_off + key_len, entry_len);
 127         hfs_bnode_dump(node);
 128
 129         if (new_node) {
 130                 /* update parent key if we inserted a key
 131                  * at the start of the first node
 132                  */
 133                 if (!rec && new_node != node)
 134                         hfs_brec_update_parent(fd);
 135
 136                 hfs_bnode_put(fd->bnode);
 137                 if (!new_node->parent) {
 138                         hfs_btree_inc_height(tree);
 139                         new_node->parent = tree->root;
 140                 }
 141                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 142
 143                 /* create index data entry */
 144                 cnid = cpu_to_be32(new_node->this);
 145                 entry = &cnid;
 146                 entry_len = sizeof(cnid);
 147
 148                 /* get index key */
 149                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 150                 __hfs_brec_find(fd->bnode, fd);
 151
 152                 hfs_bnode_put(new_node);
 153                 new_node = NULL;
 154
 155                 if (tree->attributes & HFS_TREE_VARIDXKEYS)
 156                         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
 157                 else {
 158                         fd->search_key->key_len =
 159                                 cpu_to_be16(tree->max_key_len);
 160                         key_len = tree->max_key_len + 2;
 161                 }
 162                 goto again;
 163         }
 164
 165         if (!rec)
 166                 hfs_brec_update_parent(fd);
 167
 168         return 0;
 169 }
 170
 171 int hfs_brec_remove(struct hfs_find_data *fd)
 172 {
 173         struct hfs_btree *tree;
 174         struct hfs_bnode *node, *parent;
 175         int end_off, rec_off, data_off, size;
 176
 177         tree = fd->tree;
 178         node = fd->bnode;
 179 again:
 180         rec_off = tree->node_size - (fd->record + 2) * 2;
 181         end_off = tree->node_size - (node->num_recs + 1) * 2;
 182
 183         if (node->type == HFS_NODE_LEAF) {
 184                 tree->leaf_count--;
 185                 mark_inode_dirty(tree->inode);
 186         }
 187         hfs_bnode_dump(node);
 188         dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n",
 189                 fd->record, fd->keylength + fd->entrylength);
 190         if (!--node->num_recs) {
 191                 hfs_bnode_unlink(node);
 192                 if (!node->parent)
 193                         return 0;
 194                 parent = hfs_bnode_find(tree, node->parent);
 195                 if (IS_ERR(parent))
 196                         return PTR_ERR(parent);
 197                 hfs_bnode_put(node);
 198                 node = fd->bnode = parent;
 199
 200                 __hfs_brec_find(node, fd);
 201                 goto again;
 202         }
 203         hfs_bnode_write_u16(node,
 204                 offsetof(struct hfs_bnode_desc, num_recs),
 205                 node->num_recs);
 206
 207         if (rec_off == end_off)
 208                 goto skip;
 209         size = fd->keylength + fd->entrylength;
 210
 211         do {
 212                 data_off = hfs_bnode_read_u16(node, rec_off);
 213                 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
 214                 rec_off -= 2;
 215         } while (rec_off >= end_off);
 216
 217         /* fill hole */
 218         hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
 219                        data_off - fd->keyoffset - size);
 220 skip:
 221         hfs_bnode_dump(node);
 222         if (!fd->record)
 223                 hfs_brec_update_parent(fd);
 224         return 0;
 225 }
 226
 227 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
 228 {
 229         struct hfs_btree *tree;
 230         struct hfs_bnode *node, *new_node, *next_node;
 231         struct hfs_bnode_desc node_desc;
 232         int num_recs, new_rec_off, new_off, old_rec_off;
 233         int data_start, data_end, size;
 234
 235         tree = fd->tree;
 236         node = fd->bnode;
 237         new_node = hfs_bmap_alloc(tree);
 238         if (IS_ERR(new_node))
 239                 return new_node;
 240         hfs_bnode_get(node);
 241         dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
 242                 node->this, new_node->this, node->next);
 243         new_node->next = node->next;
 244         new_node->prev = node->this;
 245         new_node->parent = node->parent;
 246         new_node->type = node->type;
 247         new_node->height = node->height;
 248
 249         if (node->next)
 250                 next_node = hfs_bnode_find(tree, node->next);
 251         else
 252                 next_node = NULL;
 253
 254         if (IS_ERR(next_node)) {
 255                 hfs_bnode_put(node);
 256                 hfs_bnode_put(new_node);
 257                 return next_node;
 258         }
 259
 260         size = tree->node_size / 2 - node->num_recs * 2 - 14;
 261         old_rec_off = tree->node_size - 4;
 262         num_recs = 1;
 263         for (;;) {
 264                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 265                 if (data_start > size)
 266                         break;
 267                 old_rec_off -= 2;
 268                 if (++num_recs < node->num_recs)
 269                         continue;
 270                 /* panic? */
 271                 hfs_bnode_put(node);
 272                 hfs_bnode_put(new_node);
 273                 if (next_node)
 274                         hfs_bnode_put(next_node);
 275                 return ERR_PTR(-ENOSPC);
 276         }
 277
 278         if (fd->record + 1 < num_recs) {
 279                 /* new record is in the lower half,
 280                  * so leave some more space there
 281                  */
 282                 old_rec_off += 2;
 283                 num_recs--;
 284                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 285         } else {
 286                 hfs_bnode_put(node);
 287                 hfs_bnode_get(new_node);
 288                 fd->bnode = new_node;
 289                 fd->record -= num_recs;
 290                 fd->keyoffset -= data_start - 14;
 291                 fd->entryoffset -= data_start - 14;
 292         }
 293         new_node->num_recs = node->num_recs - num_recs;
 294         node->num_recs = num_recs;
 295
 296         new_rec_off = tree->node_size - 2;
 297         new_off = 14;
 298         size = data_start - new_off;
 299         num_recs = new_node->num_recs;
 300         data_end = data_start;
 301         while (num_recs) {
 302                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 303                 old_rec_off -= 2;
 304                 new_rec_off -= 2;
 305                 data_end = hfs_bnode_read_u16(node, old_rec_off);
 306                 new_off = data_end - size;
 307                 num_recs--;
 308         }
 309         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 310         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 311
 312         /* update new bnode header */
 313         node_desc.next = cpu_to_be32(new_node->next);
 314         node_desc.prev = cpu_to_be32(new_node->prev);
 315         node_desc.type = new_node->type;
 316         node_desc.height = new_node->height;
 317         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 318         node_desc.reserved = 0;
 319         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 320
 321         /* update previous bnode header */
 322         node->next = new_node->this;
 323         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 324         node_desc.next = cpu_to_be32(node->next);
 325         node_desc.num_recs = cpu_to_be16(node->num_recs);
 326         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 327
 328         /* update next bnode header */
 329         if (next_node) {
 330                 next_node->prev = new_node->this;
 331                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 332                 node_desc.prev = cpu_to_be32(next_node->prev);
 333                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 334                 hfs_bnode_put(next_node);
 335         } else if (node->this == tree->leaf_tail) {
 336                 /* if there is no next node, this might be the new tail */
 337                 tree->leaf_tail = new_node->this;
 338                 mark_inode_dirty(tree->inode);
 339         }
 340
 341         hfs_bnode_dump(node);
 342         hfs_bnode_dump(new_node);
 343         hfs_bnode_put(node);
 344
 345         return new_node;
 346 }
 347
 348 static int hfs_brec_update_parent(struct hfs_find_data *fd)
 349 {
 350         struct hfs_btree *tree;
 351         struct hfs_bnode *node, *new_node, *parent;
 352         int newkeylen, diff;
 353         int rec, rec_off, end_rec_off;
 354         int start_off, end_off;
 355
 356         tree = fd->tree;
 357         node = fd->bnode;
 358         new_node = NULL;
 359         if (!node->parent)
 360                 return 0;
 361
 362 again:
 363         parent = hfs_bnode_find(tree, node->parent);
 364         if (IS_ERR(parent))
 365                 return PTR_ERR(parent);
 366         __hfs_brec_find(parent, fd);
 367         hfs_bnode_dump(parent);
 368         rec = fd->record;
 369
 370         /* size difference between old and new key */
 371         if (tree->attributes & HFS_TREE_VARIDXKEYS)
 372                 newkeylen = hfs_bnode_read_u16(node, 14) + 2;
 373         else
 374                 fd->keylength = newkeylen = tree->max_key_len + 2;
 375         dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n",
 376                 rec, fd->keylength, newkeylen);
 377
 378         rec_off = tree->node_size - (rec + 2) * 2;
 379         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 380         diff = newkeylen - fd->keylength;
 381         if (!diff)
 382                 goto skip;
 383         if (diff > 0) {
 384                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
 385                 if (end_rec_off - end_off < diff) {
 386
 387                         dprint(DBG_BNODE_MOD, "hfs: splitting index node.\n");
 388                         fd->bnode = parent;
 389                         new_node = hfs_bnode_split(fd);
 390                         if (IS_ERR(new_node))
 391                                 return PTR_ERR(new_node);
 392                         parent = fd->bnode;
 393                         rec = fd->record;
 394                         rec_off = tree->node_size - (rec + 2) * 2;
 395                         end_rec_off = tree->node_size -
 396                                 (parent->num_recs + 1) * 2;
 397                 }
 398         }
 399
 400         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 401         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 402         start_off -= 4; /* move previous cnid too */
 403
 404         while (rec_off > end_rec_off) {
 405                 rec_off -= 2;
 406                 end_off = hfs_bnode_read_u16(parent, rec_off);
 407                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 408         }
 409         hfs_bnode_move(parent, start_off + diff, start_off,
 410                        end_off - start_off);
 411 skip:
 412         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 413         hfs_bnode_dump(parent);
 414
 415         hfs_bnode_put(node);
 416         node = parent;
 417
 418         if (new_node) {
 419                 __be32 cnid;
 420
 421                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 422                 /* create index key and entry */
 423                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 424                 cnid = cpu_to_be32(new_node->this);
 425
 426                 __hfs_brec_find(fd->bnode, fd);
 427                 hfs_brec_insert(fd, &cnid, sizeof(cnid));
 428                 hfs_bnode_put(fd->bnode);
 429                 hfs_bnode_put(new_node);
 430
 431                 if (!rec) {
 432                         if (new_node == node)
 433                                 goto out;
 434                         /* restore search_key */
 435                         hfs_bnode_read_key(node, fd->search_key, 14);
 436                 }
 437         }
 438
 439         if (!rec && node->parent)
 440                 goto again;
 441 out:
 442         fd->bnode = node;
 443         return 0;
 444 }
 445
 446 static int hfs_btree_inc_height(struct hfs_btree *tree)
 447 {
 448         struct hfs_bnode *node, *new_node;
 449         struct hfs_bnode_desc node_desc;
 450         int key_size, rec;
 451         __be32 cnid;
 452
 453         node = NULL;
 454         if (tree->root) {
 455                 node = hfs_bnode_find(tree, tree->root);
 456                 if (IS_ERR(node))
 457                         return PTR_ERR(node);
 458         }
 459         new_node = hfs_bmap_alloc(tree);
 460         if (IS_ERR(new_node)) {
 461                 hfs_bnode_put(node);
 462                 return PTR_ERR(new_node);
 463         }
 464
 465         tree->root = new_node->this;
 466         if (!tree->depth) {
 467                 tree->leaf_head = tree->leaf_tail = new_node->this;
 468                 new_node->type = HFS_NODE_LEAF;
 469                 new_node->num_recs = 0;
 470         } else {
 471                 new_node->type = HFS_NODE_INDEX;
 472                 new_node->num_recs = 1;
 473         }
 474         new_node->parent = 0;
 475         new_node->next = 0;
 476         new_node->prev = 0;
 477         new_node->height = ++tree->depth;
 478
 479         node_desc.next = cpu_to_be32(new_node->next);
 480         node_desc.prev = cpu_to_be32(new_node->prev);
 481         node_desc.type = new_node->type;
 482         node_desc.height = new_node->height;
 483         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 484         node_desc.reserved = 0;
 485         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 486
 487         rec = tree->node_size - 2;
 488         hfs_bnode_write_u16(new_node, rec, 14);
 489
 490         if (node) {
 491                 /* insert old root idx into new root */
 492                 node->parent = tree->root;
 493                 if (node->type == HFS_NODE_LEAF ||
 494                     tree->attributes & HFS_TREE_VARIDXKEYS)
 495                         key_size = hfs_bnode_read_u16(node, 14) + 2;
 496                 else
 497                         key_size = tree->max_key_len + 2;
 498                 hfs_bnode_copy(new_node, 14, node, 14, key_size);
 499
 500                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
 501                         key_size = tree->max_key_len + 2;
 502                         hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
 503                 }
 504                 cnid = cpu_to_be32(node->this);
 505                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 506
 507                 rec -= 2;
 508                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 509
 510                 hfs_bnode_put(node);
 511         }
 512         hfs_bnode_put(new_node);
 513         mark_inode_dirty(tree->inode);
 514
 515         return 0;
 516 }