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 /* Get the length and offset of the given record in the given node */
  15 u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
  16 {
  17         u16 retval[2];
  18         u16 dataoff;
  19
  20         dataoff = node->tree->node_size - (rec + 2) * 2;
  21         hfs_bnode_read(node, retval, dataoff, 4);
  22         *off = be16_to_cpu(retval[1]);
  23         return be16_to_cpu(retval[0]) - *off;
  24 }
  25
  26 /* Get the length of the key from a keyed record */
  27 u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
  28 {
  29         u16 retval, recoff;
  30
  31         if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
  32                 return 0;
  33
  34         if ((node->type == HFS_NODE_INDEX) &&
  35            !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
  36                 retval = node->tree->max_key_len + 2;
  37         } else {
  38                 recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
  39                 if (!recoff)
  40                         return 0;
  41                 if (node->tree->attributes & HFS_TREE_BIGKEYS)
  42                         retval = hfs_bnode_read_u16(node, recoff) + 2;
  43                 else
  44                         retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
  45         }
  46         return retval;
  47 }
  48
  49 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  50 {
  51         struct hfs_btree *tree;
  52         struct hfs_bnode *node, *new_node;
  53         int size, key_len, rec;
  54         int data_off, end_off;
  55         int idx_rec_off, data_rec_off, end_rec_off;
  56         u32 cnid;
  57
  58         tree = fd->tree;
  59         if (!fd->bnode) {
  60                 if (!tree->root)
  61                         hfs_btree_inc_height(tree);
  62                 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  63                 if (IS_ERR(fd->bnode))
  64                         return PTR_ERR(fd->bnode);
  65                 fd->record = -1;
  66         }
  67         new_node = NULL;
  68         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
  69 again:
  70         /* new record idx and complete record size */
  71         rec = fd->record + 1;
  72         size = key_len + entry_len;
  73
  74         node = fd->bnode;
  75         hfs_bnode_dump(node);
  76         /* get last offset */
  77         end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  78         end_off = hfs_bnode_read_u16(node, end_rec_off);
  79         end_rec_off -= 2;
  80         dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
  81         if (size > end_rec_off - end_off) {
  82                 if (new_node)
  83                         panic("not enough room!\n");
  84                 new_node = hfs_bnode_split(fd);
  85                 if (IS_ERR(new_node))
  86                         return PTR_ERR(new_node);
  87                 goto again;
  88         }
  89         if (node->type == HFS_NODE_LEAF) {
  90                 tree->leaf_count++;
  91                 mark_inode_dirty(tree->inode);
  92         }
  93         node->num_recs++;
  94         /* write new last offset */
  95         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
  96         hfs_bnode_write_u16(node, end_rec_off, end_off + size);
  97         data_off = end_off;
  98         data_rec_off = end_rec_off + 2;
  99         idx_rec_off = tree->node_size - (rec + 1) * 2;
 100         if (idx_rec_off == data_rec_off)
 101                 goto skip;
 102         /* move all following entries */
 103         do {
 104                 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
 105                 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
 106                 data_rec_off += 2;
 107         } while (data_rec_off < idx_rec_off);
 108
 109         /* move data away */
 110         hfs_bnode_move(node, data_off + size, data_off,
 111                        end_off - data_off);
 112
 113 skip:
 114         hfs_bnode_write(node, fd->search_key, data_off, key_len);
 115         hfs_bnode_write(node, entry, data_off + key_len, entry_len);
 116         hfs_bnode_dump(node);
 117
 118         if (new_node) {
 119                 /* update parent key if we inserted a key
 120                  * at the start of the first node
 121                  */
 122                 if (!rec && new_node != node)
 123                         hfs_brec_update_parent(fd);
 124
 125                 hfs_bnode_put(fd->bnode);
 126                 if (!new_node->parent) {
 127                         hfs_btree_inc_height(tree);
 128                         new_node->parent = tree->root;
 129                 }
 130                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 131
 132                 /* create index data entry */
 133                 cnid = cpu_to_be32(new_node->this);
 134                 entry = &cnid;
 135                 entry_len = sizeof(cnid);
 136
 137                 /* get index key */
 138                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 139                 __hfs_brec_find(fd->bnode, fd);
 140
 141                 hfs_bnode_put(new_node);
 142                 new_node = NULL;
 143
 144                 if (tree->attributes & HFS_TREE_VARIDXKEYS)
 145                         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
 146                 else {
 147                         fd->search_key->key_len = cpu_to_be16(tree->max_key_len);
 148                         key_len = tree->max_key_len + 2;
 149                 }
 150                 goto again;
 151         }
 152
 153         if (!rec)
 154                 hfs_brec_update_parent(fd);
 155
 156         return 0;
 157 }
 158
 159 int hfs_brec_remove(struct hfs_find_data *fd)
 160 {
 161         struct hfs_btree *tree;
 162         struct hfs_bnode *node, *parent;
 163         int end_off, rec_off, data_off, size;
 164
 165         tree = fd->tree;
 166         node = fd->bnode;
 167 again:
 168         rec_off = tree->node_size - (fd->record + 2) * 2;
 169         end_off = tree->node_size - (node->num_recs + 1) * 2;
 170
 171         if (node->type == HFS_NODE_LEAF) {
 172                 tree->leaf_count--;
 173                 mark_inode_dirty(tree->inode);
 174         }
 175         hfs_bnode_dump(node);
 176         dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", fd->record, fd->keylength + fd->entrylength);
 177         if (!--node->num_recs) {
 178                 hfs_bnode_unlink(node);
 179                 if (!node->parent)
 180                         return 0;
 181                 parent = hfs_bnode_find(tree, node->parent);
 182                 if (IS_ERR(parent))
 183                         return PTR_ERR(parent);
 184                 hfs_bnode_put(node);
 185                 node = fd->bnode = parent;
 186
 187                 __hfs_brec_find(node, fd);
 188                 goto again;
 189         }
 190         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 191
 192         if (rec_off == end_off)
 193                 goto skip;
 194         size = fd->keylength + fd->entrylength;
 195
 196         do {
 197                 data_off = hfs_bnode_read_u16(node, rec_off);
 198                 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
 199                 rec_off -= 2;
 200         } while (rec_off >= end_off);
 201
 202         /* fill hole */
 203         hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
 204                        data_off - fd->keyoffset - size);
 205 skip:
 206         hfs_bnode_dump(node);
 207         if (!fd->record)
 208                 hfs_brec_update_parent(fd);
 209         return 0;
 210 }
 211
 212 struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
 213 {
 214         struct hfs_btree *tree;
 215         struct hfs_bnode *node, *new_node;
 216         struct hfs_bnode_desc node_desc;
 217         int num_recs, new_rec_off, new_off, old_rec_off;
 218         int data_start, data_end, size;
 219
 220         tree = fd->tree;
 221         node = fd->bnode;
 222         new_node = hfs_bmap_alloc(tree);
 223         if (IS_ERR(new_node))
 224                 return new_node;
 225         hfs_bnode_get(node);
 226         dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
 227                 node->this, new_node->this, node->next);
 228         new_node->next = node->next;
 229         new_node->prev = node->this;
 230         new_node->parent = node->parent;
 231         new_node->type = node->type;
 232         new_node->height = node->height;
 233
 234         size = tree->node_size / 2 - node->num_recs * 2 - 14;
 235         old_rec_off = tree->node_size - 4;
 236         num_recs = 1;
 237         for (;;) {
 238                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 239                 if (data_start > size)
 240                         break;
 241                 old_rec_off -= 2;
 242                 if (++num_recs < node->num_recs)
 243                         continue;
 244                 /* panic? */
 245                 hfs_bnode_put(node);
 246                 hfs_bnode_put(new_node);
 247                 return ERR_PTR(-ENOSPC);
 248         }
 249
 250         if (fd->record + 1 < num_recs) {
 251                 /* new record is in the lower half,
 252                  * so leave some more space there
 253                  */
 254                 old_rec_off += 2;
 255                 num_recs--;
 256                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 257         } else {
 258                 hfs_bnode_put(node);
 259                 hfs_bnode_get(new_node);
 260                 fd->bnode = new_node;
 261                 fd->record -= num_recs;
 262                 fd->keyoffset -= data_start - 14;
 263                 fd->entryoffset -= data_start - 14;
 264         }
 265         new_node->num_recs = node->num_recs - num_recs;
 266         node->num_recs = num_recs;
 267
 268         new_rec_off = tree->node_size - 2;
 269         new_off = 14;
 270         size = data_start - new_off;
 271         num_recs = new_node->num_recs;
 272         data_end = data_start;
 273         while (num_recs) {
 274                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 275                 old_rec_off -= 2;
 276                 new_rec_off -= 2;
 277                 data_end = hfs_bnode_read_u16(node, old_rec_off);
 278                 new_off = data_end - size;
 279                 num_recs--;
 280         }
 281         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 282         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 283
 284         /* update new bnode header */
 285         node_desc.next = cpu_to_be32(new_node->next);
 286         node_desc.prev = cpu_to_be32(new_node->prev);
 287         node_desc.type = new_node->type;
 288         node_desc.height = new_node->height;
 289         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 290         node_desc.reserved = 0;
 291         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 292
 293         /* update previous bnode header */
 294         node->next = new_node->this;
 295         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 296         node_desc.next = cpu_to_be32(node->next);
 297         node_desc.num_recs = cpu_to_be16(node->num_recs);
 298         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 299
 300         /* update next bnode header */
 301         if (new_node->next) {
 302                 struct hfs_bnode *next_node = hfs_bnode_find(tree, new_node->next);
 303                 next_node->prev = new_node->this;
 304                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 305                 node_desc.prev = cpu_to_be32(next_node->prev);
 306                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 307                 hfs_bnode_put(next_node);
 308         } else if (node->this == tree->leaf_tail) {
 309                 /* if there is no next node, this might be the new tail */
 310                 tree->leaf_tail = new_node->this;
 311                 mark_inode_dirty(tree->inode);
 312         }
 313
 314         hfs_bnode_dump(node);
 315         hfs_bnode_dump(new_node);
 316         hfs_bnode_put(node);
 317
 318         return new_node;
 319 }
 320
 321 int hfs_brec_update_parent(struct hfs_find_data *fd)
 322 {
 323         struct hfs_btree *tree;
 324         struct hfs_bnode *node, *new_node, *parent;
 325         int newkeylen, diff;
 326         int rec, rec_off, end_rec_off;
 327         int start_off, end_off;
 328
 329         tree = fd->tree;
 330         node = fd->bnode;
 331         new_node = NULL;
 332         if (!node->parent)
 333                 return 0;
 334
 335 again:
 336         parent = hfs_bnode_find(tree, node->parent);
 337         if (IS_ERR(parent))
 338                 return PTR_ERR(parent);
 339         __hfs_brec_find(parent, fd);
 340         hfs_bnode_dump(parent);
 341         rec = fd->record;
 342
 343         /* size difference between old and new key */
 344         if (tree->attributes & HFS_TREE_VARIDXKEYS)
 345                 newkeylen = hfs_bnode_read_u16(node, 14) + 2;
 346         else
 347                 fd->keylength = newkeylen = tree->max_key_len + 2;
 348         dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
 349
 350         rec_off = tree->node_size - (rec + 2) * 2;
 351         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 352         diff = newkeylen - fd->keylength;
 353         if (!diff)
 354                 goto skip;
 355         if (diff > 0) {
 356                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
 357                 if (end_rec_off - end_off < diff) {
 358
 359                         printk("splitting index node...\n");
 360                         fd->bnode = parent;
 361                         new_node = hfs_bnode_split(fd);
 362                         if (IS_ERR(new_node))
 363                                 return PTR_ERR(new_node);
 364                         parent = fd->bnode;
 365                         rec = fd->record;
 366                         rec_off = tree->node_size - (rec + 2) * 2;
 367                         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 368                 }
 369         }
 370
 371         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 372         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 373         start_off -= 4; /* move previous cnid too */
 374
 375         while (rec_off > end_rec_off) {
 376                 rec_off -= 2;
 377                 end_off = hfs_bnode_read_u16(parent, rec_off);
 378                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 379         }
 380         hfs_bnode_move(parent, start_off + diff, start_off,
 381                        end_off - start_off);
 382 skip:
 383         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 384         hfs_bnode_dump(parent);
 385
 386         hfs_bnode_put(node);
 387         node = parent;
 388
 389         if (new_node) {
 390                 u32 cnid;
 391
 392                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 393                 /* create index key and entry */
 394                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 395                 cnid = cpu_to_be32(new_node->this);
 396
 397                 __hfs_brec_find(fd->bnode, fd);
 398                 hfs_brec_insert(fd, &cnid, sizeof(cnid));
 399                 hfs_bnode_put(fd->bnode);
 400                 hfs_bnode_put(new_node);
 401
 402                 if (!rec) {
 403                         if (new_node == node)
 404                                 goto out;
 405                         /* restore search_key */
 406                         hfs_bnode_read_key(node, fd->search_key, 14);
 407                 }
 408         }
 409
 410         if (!rec && node->parent)
 411                 goto again;
 412 out:
 413         fd->bnode = node;
 414         return 0;
 415 }
 416
 417 int hfs_btree_inc_height(struct hfs_btree *tree)
 418 {
 419         struct hfs_bnode *node, *new_node;
 420         struct hfs_bnode_desc node_desc;
 421         int key_size, rec;
 422         u32 cnid;
 423
 424         node = NULL;
 425         if (tree->root) {
 426                 node = hfs_bnode_find(tree, tree->root);
 427                 if (IS_ERR(node))
 428                         return PTR_ERR(node);
 429         }
 430         new_node = hfs_bmap_alloc(tree);
 431         if (IS_ERR(new_node)) {
 432                 hfs_bnode_put(node);
 433                 return PTR_ERR(new_node);
 434         }
 435
 436         tree->root = new_node->this;
 437         if (!tree->depth) {
 438                 tree->leaf_head = tree->leaf_tail = new_node->this;
 439                 new_node->type = HFS_NODE_LEAF;
 440                 new_node->num_recs = 0;
 441         } else {
 442                 new_node->type = HFS_NODE_INDEX;
 443                 new_node->num_recs = 1;
 444         }
 445         new_node->parent = 0;
 446         new_node->next = 0;
 447         new_node->prev = 0;
 448         new_node->height = ++tree->depth;
 449
 450         node_desc.next = cpu_to_be32(new_node->next);
 451         node_desc.prev = cpu_to_be32(new_node->prev);
 452         node_desc.type = new_node->type;
 453         node_desc.height = new_node->height;
 454         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 455         node_desc.reserved = 0;
 456         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 457
 458         rec = tree->node_size - 2;
 459         hfs_bnode_write_u16(new_node, rec, 14);
 460
 461         if (node) {
 462                 /* insert old root idx into new root */
 463                 node->parent = tree->root;
 464                 if (node->type == HFS_NODE_LEAF ||
 465                     tree->attributes & HFS_TREE_VARIDXKEYS)
 466                         key_size = hfs_bnode_read_u16(node, 14) + 2;
 467                 else
 468                         key_size = tree->max_key_len + 2;
 469                 hfs_bnode_copy(new_node, 14, node, 14, key_size);
 470
 471                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
 472                         key_size = tree->max_key_len + 2;
 473                         hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
 474                 }
 475                 cnid = cpu_to_be32(node->this);
 476                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 477
 478                 rec -= 2;
 479                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 480
 481                 hfs_bnode_put(node);
 482         }
 483         hfs_bnode_put(new_node);
 484         mark_inode_dirty(tree->inode);
 485
 486         return 0;
 487 }