fs/hfs/brec.c

   1 /*
   2  *  linux/fs/hfs/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 "btree.h"
  12
  13 /* Get the length and offset of the given record in the given node */
  14 u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
  15 {
  16         u16 retval[2];
  17         u16 dataoff;
  18
  19         dataoff = node->tree->node_size - (rec + 2) * 2;
  20         hfs_bnode_read(node, retval, dataoff, 4);
  21         *off = be16_to_cpu(retval[1]);
  22         return be16_to_cpu(retval[0]) - *off;
  23 }
  24
  25 /* Get the length of the key from a keyed record */
  26 u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
  27 {
  28         u16 retval, recoff;
  29
  30         if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
  31                 return 0;
  32
  33         if ((node->type == HFS_NODE_INDEX) &&
  34            !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
  35                 if (node->tree->attributes & HFS_TREE_BIGKEYS)
  36                         retval = node->tree->max_key_len + 2;
  37                 else
  38                         retval = node->tree->max_key_len + 1;
  39         } else {
  40                 recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
  41                 if (!recoff)
  42                         return 0;
  43                 if (node->tree->attributes & HFS_TREE_BIGKEYS)
  44                         retval = hfs_bnode_read_u16(node, recoff) + 2;
  45                 else
  46                         retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
  47         }
  48         return retval;
  49 }
  50
  51 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  52 {
  53         struct hfs_btree *tree;
  54         struct hfs_bnode *node, *new_node;
  55         int size, key_len, rec;
  56         int data_off, end_off;
  57         int idx_rec_off, data_rec_off, end_rec_off;
  58         u32 cnid;
  59
  60         tree = fd->tree;
  61         if (!fd->bnode) {
  62                 if (!tree->root)
  63                         hfs_btree_inc_height(tree);
  64                 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  65                 if (IS_ERR(fd->bnode))
  66                         return PTR_ERR(fd->bnode);
  67                 fd->record = -1;
  68         }
  69         new_node = NULL;
  70         key_len = (fd->search_key->key_len | 1) + 1;
  71 again:
  72         /* new record idx and complete record size */
  73         rec = fd->record + 1;
  74         size = key_len + entry_len;
  75
  76         node = fd->bnode;
  77         hfs_bnode_dump(node);
  78         /* get last offset */
  79         end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  80         end_off = hfs_bnode_read_u16(node, end_rec_off);
  81         end_rec_off -= 2;
  82         dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
  83         if (size > end_rec_off - end_off) {
  84                 if (new_node)
  85                         panic("not enough room!\n");
  86                 new_node = hfs_bnode_split(fd);
  87                 if (IS_ERR(new_node))
  88                         return PTR_ERR(new_node);
  89                 goto again;
  90         }
  91         if (node->type == HFS_NODE_LEAF) {
  92                 tree->leaf_count++;
  93                 mark_inode_dirty(tree->inode);
  94         }
  95         node->num_recs++;
  96         /* write new last offset */
  97         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
  98         hfs_bnode_write_u16(node, end_rec_off, end_off + size);
  99         data_off = end_off;
 100         data_rec_off = end_rec_off + 2;
 101         idx_rec_off = tree->node_size - (rec + 1) * 2;
 102         if (idx_rec_off == data_rec_off)
 103                 goto skip;
 104         /* move all following entries */
 105         do {
 106                 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
 107                 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
 108                 data_rec_off += 2;
 109         } while (data_rec_off < idx_rec_off);
 110
 111         /* move data away */
 112         hfs_bnode_move(node, data_off + size, data_off,
 113                        end_off - data_off);
 114
 115 skip:
 116         hfs_bnode_write(node, fd->search_key, data_off, key_len);
 117         hfs_bnode_write(node, entry, data_off + key_len, entry_len);
 118         hfs_bnode_dump(node);
 119
 120         if (new_node) {
 121                 /* update parent key if we inserted a key
 122                  * at the start of the first node
 123                  */
 124                 if (!rec && new_node != node)
 125                         hfs_brec_update_parent(fd);
 126
 127                 hfs_bnode_put(fd->bnode);
 128                 if (!new_node->parent) {
 129                         hfs_btree_inc_height(tree);
 130                         new_node->parent = tree->root;
 131                 }
 132                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 133
 134                 /* create index data entry */
 135                 cnid = cpu_to_be32(new_node->this);
 136                 entry = &cnid;
 137                 entry_len = sizeof(cnid);
 138
 139                 /* get index key */
 140                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 141                 __hfs_brec_find(fd->bnode, fd);
 142
 143                 hfs_bnode_put(new_node);
 144                 new_node = NULL;
 145
 146                 if (tree->attributes & HFS_TREE_VARIDXKEYS)
 147                         key_len = fd->search_key->key_len + 1;
 148                 else {
 149                         fd->search_key->key_len = tree->max_key_len;
 150                         key_len = tree->max_key_len + 1;
 151                 }
 152                 goto again;
 153         }
 154
 155         if (!rec)
 156                 hfs_brec_update_parent(fd);
 157
 158         return 0;
 159 }
 160
 161 int hfs_brec_remove(struct hfs_find_data *fd)
 162 {
 163         struct hfs_btree *tree;
 164         struct hfs_bnode *node, *parent;
 165         int end_off, rec_off, data_off, size;
 166
 167         tree = fd->tree;
 168         node = fd->bnode;
 169 again:
 170         rec_off = tree->node_size - (fd->record + 2) * 2;
 171         end_off = tree->node_size - (node->num_recs + 1) * 2;
 172
 173         if (node->type == HFS_NODE_LEAF) {
 174                 tree->leaf_count--;
 175                 mark_inode_dirty(tree->inode);
 176         }
 177         hfs_bnode_dump(node);
 178         dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", fd->record, fd->keylength + fd->entrylength);
 179         if (!--node->num_recs) {
 180                 hfs_bnode_unlink(node);
 181                 if (!node->parent)
 182                         return 0;
 183                 parent = hfs_bnode_find(tree, node->parent);
 184                 if (IS_ERR(parent))
 185                         return PTR_ERR(parent);
 186                 hfs_bnode_put(node);
 187                 node = fd->bnode = parent;
 188
 189                 __hfs_brec_find(node, fd);
 190                 goto again;
 191         }
 192         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 193
 194         if (rec_off == end_off)
 195                 goto skip;
 196         size = fd->keylength + fd->entrylength;
 197
 198         do {
 199                 data_off = hfs_bnode_read_u16(node, rec_off);
 200                 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
 201                 rec_off -= 2;
 202         } while (rec_off >= end_off);
 203
 204         /* fill hole */
 205         hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
 206                        data_off - fd->keyoffset - size);
 207 skip:
 208         hfs_bnode_dump(node);
 209         if (!fd->record)
 210                 hfs_brec_update_parent(fd);
 211         return 0;
 212 }
 213
 214 struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
 215 {
 216         struct hfs_btree *tree;
 217         struct hfs_bnode *node, *new_node;
 218         struct hfs_bnode_desc node_desc;
 219         int num_recs, new_rec_off, new_off, old_rec_off;
 220         int data_start, data_end, size;
 221
 222         tree = fd->tree;
 223         node = fd->bnode;
 224         new_node = hfs_bmap_alloc(tree);
 225         if (IS_ERR(new_node))
 226                 return new_node;
 227         hfs_bnode_get(node);
 228         dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
 229                 node->this, new_node->this, node->next);
 230         new_node->next = node->next;
 231         new_node->prev = node->this;
 232         new_node->parent = node->parent;
 233         new_node->type = node->type;
 234         new_node->height = node->height;
 235
 236         size = tree->node_size / 2 - node->num_recs * 2 - 14;
 237         old_rec_off = tree->node_size - 4;
 238         num_recs = 1;
 239         for (;;) {
 240                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 241                 if (data_start > size)
 242                         break;
 243                 old_rec_off -= 2;
 244                 if (++num_recs < node->num_recs)
 245                         continue;
 246                 /* panic? */
 247                 hfs_bnode_put(node);
 248                 hfs_bnode_put(new_node);
 249                 return ERR_PTR(-ENOSPC);
 250         }
 251
 252         if (fd->record + 1 < num_recs) {
 253                 /* new record is in the lower half,
 254                  * so leave some more space there
 255                  */
 256                 old_rec_off += 2;
 257                 num_recs--;
 258                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 259         } else {
 260                 hfs_bnode_put(node);
 261                 hfs_bnode_get(new_node);
 262                 fd->bnode = new_node;
 263                 fd->record -= num_recs;
 264                 fd->keyoffset -= data_start - 14;
 265                 fd->entryoffset -= data_start - 14;
 266         }
 267         new_node->num_recs = node->num_recs - num_recs;
 268         node->num_recs = num_recs;
 269
 270         new_rec_off = tree->node_size - 2;
 271         new_off = 14;
 272         size = data_start - new_off;
 273         num_recs = new_node->num_recs;
 274         data_end = data_start;
 275         while (num_recs) {
 276                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 277                 old_rec_off -= 2;
 278                 new_rec_off -= 2;
 279                 data_end = hfs_bnode_read_u16(node, old_rec_off);
 280                 new_off = data_end - size;
 281                 num_recs--;
 282         }
 283         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 284         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 285
 286         /* update new bnode header */
 287         node_desc.next = cpu_to_be32(new_node->next);
 288         node_desc.prev = cpu_to_be32(new_node->prev);
 289         node_desc.type = new_node->type;
 290         node_desc.height = new_node->height;
 291         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 292         node_desc.reserved = 0;
 293         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 294
 295         /* update previous bnode header */
 296         node->next = new_node->this;
 297         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 298         node_desc.next = cpu_to_be32(node->next);
 299         node_desc.num_recs = cpu_to_be16(node->num_recs);
 300         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 301
 302         /* update next bnode header */
 303         if (new_node->next) {
 304                 struct hfs_bnode *next_node = hfs_bnode_find(tree, new_node->next);
 305                 next_node->prev = new_node->this;
 306                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 307                 node_desc.prev = cpu_to_be32(next_node->prev);
 308                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 309                 hfs_bnode_put(next_node);
 310         } else if (node->this == tree->leaf_tail) {
 311                 /* if there is no next node, this might be the new tail */
 312                 tree->leaf_tail = new_node->this;
 313                 mark_inode_dirty(tree->inode);
 314         }
 315
 316         hfs_bnode_dump(node);
 317         hfs_bnode_dump(new_node);
 318         hfs_bnode_put(node);
 319
 320         return new_node;
 321 }
 322
 323 int hfs_brec_update_parent(struct hfs_find_data *fd)
 324 {
 325         struct hfs_btree *tree;
 326         struct hfs_bnode *node, *new_node, *parent;
 327         int newkeylen, diff;
 328         int rec, rec_off, end_rec_off;
 329         int start_off, end_off;
 330
 331         tree = fd->tree;
 332         node = fd->bnode;
 333         new_node = NULL;
 334         if (!node->parent)
 335                 return 0;
 336
 337 again:
 338         parent = hfs_bnode_find(tree, node->parent);
 339         if (IS_ERR(parent))
 340                 return PTR_ERR(parent);
 341         __hfs_brec_find(parent, fd);
 342         hfs_bnode_dump(parent);
 343         rec = fd->record;
 344
 345         /* size difference between old and new key */
 346         if (tree->attributes & HFS_TREE_VARIDXKEYS)
 347                 newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
 348         else
 349                 fd->keylength = newkeylen = tree->max_key_len + 1;
 350         dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
 351
 352         rec_off = tree->node_size - (rec + 2) * 2;
 353         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 354         diff = newkeylen - fd->keylength;
 355         if (!diff)
 356                 goto skip;
 357         if (diff > 0) {
 358                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
 359                 if (end_rec_off - end_off < diff) {
 360
 361                         printk("splitting index node...\n");
 362                         fd->bnode = parent;
 363                         new_node = hfs_bnode_split(fd);
 364                         if (IS_ERR(new_node))
 365                                 return PTR_ERR(new_node);
 366                         parent = fd->bnode;
 367                         rec = fd->record;
 368                         rec_off = tree->node_size - (rec + 2) * 2;
 369                         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 370                 }
 371         }
 372
 373         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 374         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 375         start_off -= 4; /* move previous cnid too */
 376
 377         while (rec_off > end_rec_off) {
 378                 rec_off -= 2;
 379                 end_off = hfs_bnode_read_u16(parent, rec_off);
 380                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 381         }
 382         hfs_bnode_move(parent, start_off + diff, start_off,
 383                        end_off - start_off);
 384 skip:
 385         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 386         if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
 387                 hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
 388         hfs_bnode_dump(parent);
 389
 390         hfs_bnode_put(node);
 391         node = parent;
 392
 393         if (new_node) {
 394                 u32 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;
 416 out:
 417         fd->bnode = node;
 418         return 0;
 419 }
 420
 421 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         u32 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_u8(node, 14) + 1;
 471                 else
 472                         key_size = tree->max_key_len + 1;
 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 + 1;
 477                         hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
 478                 }
 479                 key_size = (key_size + 1) & -2;
 480                 cnid = cpu_to_be32(node->this);
 481                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 482
 483                 rec -= 2;
 484                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 485
 486                 hfs_bnode_put(node);
 487         }
 488         hfs_bnode_put(new_node);
 489         mark_inode_dirty(tree->inode);
 490
 491         return 0;
 492 }