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 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
  14 static int hfs_brec_update_parent(struct hfs_find_data *fd);
  15 static int hfs_btree_inc_height(struct hfs_btree *tree);
  16
  17 /* Get the length and offset of the given record in the given node */
  18 u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
  19 {
  20         __be16 retval[2];
  21         u16 dataoff;
  22
  23         dataoff = node->tree->node_size - (rec + 2) * 2;
  24         hfs_bnode_read(node, retval, dataoff, 4);
  25         *off = be16_to_cpu(retval[1]);
  26         return be16_to_cpu(retval[0]) - *off;
  27 }
  28
  29 /* Get the length of the key from a keyed record */
  30 u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
  31 {
  32         u16 retval, recoff;
  33
  34         if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
  35                 return 0;
  36
  37         if ((node->type == HFS_NODE_INDEX) &&
  38            !(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
  39                 if (node->tree->attributes & HFS_TREE_BIGKEYS)
  40                         retval = node->tree->max_key_len + 2;
  41                 else
  42                         retval = node->tree->max_key_len + 1;
  43         } else {
  44                 recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
  45                 if (!recoff)
  46                         return 0;
  47                 if (node->tree->attributes & HFS_TREE_BIGKEYS) {
  48                         retval = hfs_bnode_read_u16(node, recoff) + 2;
  49                         if (retval > node->tree->max_key_len + 2) {
  50                                 printk(KERN_ERR "hfs: keylen %d too large\n",
  51                                         retval);
  52                                 retval = 0;
  53                         }
  54                 } else {
  55                         retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
  56                         if (retval > node->tree->max_key_len + 1) {
  57                                 printk(KERN_ERR "hfs: keylen %d too large\n",
  58                                         retval);
  59                                 retval = 0;
  60                         }
  61                 }
  62         }
  63         return retval;
  64 }
  65
  66 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  67 {
  68         struct hfs_btree *tree;
  69         struct hfs_bnode *node, *new_node;
  70         int size, key_len, rec;
  71         int data_off, end_off;
  72         int idx_rec_off, data_rec_off, end_rec_off;
  73         __be32 cnid;
  74
  75         tree = fd->tree;
  76         if (!fd->bnode) {
  77                 if (!tree->root)
  78                         hfs_btree_inc_height(tree);
  79                 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  80                 if (IS_ERR(fd->bnode))
  81                         return PTR_ERR(fd->bnode);
  82                 fd->record = -1;
  83         }
  84         new_node = NULL;
  85         key_len = (fd->search_key->key_len | 1) + 1;
  86 again:
  87         /* new record idx and complete record size */
  88         rec = fd->record + 1;
  89         size = key_len + entry_len;
  90
  91         node = fd->bnode;
  92         hfs_bnode_dump(node);
  93         /* get last offset */
  94         end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  95         end_off = hfs_bnode_read_u16(node, end_rec_off);
  96         end_rec_off -= 2;
  97         dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
  98         if (size > end_rec_off - end_off) {
  99                 if (new_node)
 100                         panic("not enough room!\n");
 101                 new_node = hfs_bnode_split(fd);
 102                 if (IS_ERR(new_node))
 103                         return PTR_ERR(new_node);
 104                 goto again;
 105         }
 106         if (node->type == HFS_NODE_LEAF) {
 107                 tree->leaf_count++;
 108                 mark_inode_dirty(tree->inode);
 109         }
 110         node->num_recs++;
 111         /* write new last offset */
 112         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 113         hfs_bnode_write_u16(node, end_rec_off, end_off + size);
 114         data_off = end_off;
 115         data_rec_off = end_rec_off + 2;
 116         idx_rec_off = tree->node_size - (rec + 1) * 2;
 117         if (idx_rec_off == data_rec_off)
 118                 goto skip;
 119         /* move all following entries */
 120         do {
 121                 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
 122                 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
 123                 data_rec_off += 2;
 124         } while (data_rec_off < idx_rec_off);
 125
 126         /* move data away */
 127         hfs_bnode_move(node, data_off + size, data_off,
 128                        end_off - data_off);
 129
 130 skip:
 131         hfs_bnode_write(node, fd->search_key, data_off, key_len);
 132         hfs_bnode_write(node, entry, data_off + key_len, entry_len);
 133         hfs_bnode_dump(node);
 134
 135         if (new_node) {
 136                 /* update parent key if we inserted a key
 137                  * at the start of the first node
 138                  */
 139                 if (!rec && new_node != node)
 140                         hfs_brec_update_parent(fd);
 141
 142                 hfs_bnode_put(fd->bnode);
 143                 if (!new_node->parent) {
 144                         hfs_btree_inc_height(tree);
 145                         new_node->parent = tree->root;
 146                 }
 147                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 148
 149                 /* create index data entry */
 150                 cnid = cpu_to_be32(new_node->this);
 151                 entry = &cnid;
 152                 entry_len = sizeof(cnid);
 153
 154                 /* get index key */
 155                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 156                 __hfs_brec_find(fd->bnode, fd);
 157
 158                 hfs_bnode_put(new_node);
 159                 new_node = NULL;
 160
 161                 if (tree->attributes & HFS_TREE_VARIDXKEYS)
 162                         key_len = fd->search_key->key_len + 1;
 163                 else {
 164                         fd->search_key->key_len = tree->max_key_len;
 165                         key_len = tree->max_key_len + 1;
 166                 }
 167                 goto again;
 168         }
 169
 170         if (!rec)
 171                 hfs_brec_update_parent(fd);
 172
 173         return 0;
 174 }
 175
 176 int hfs_brec_remove(struct hfs_find_data *fd)
 177 {
 178         struct hfs_btree *tree;
 179         struct hfs_bnode *node, *parent;
 180         int end_off, rec_off, data_off, size;
 181
 182         tree = fd->tree;
 183         node = fd->bnode;
 184 again:
 185         rec_off = tree->node_size - (fd->record + 2) * 2;
 186         end_off = tree->node_size - (node->num_recs + 1) * 2;
 187
 188         if (node->type == HFS_NODE_LEAF) {
 189                 tree->leaf_count--;
 190                 mark_inode_dirty(tree->inode);
 191         }
 192         hfs_bnode_dump(node);
 193         dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", 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, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 208
 209         if (rec_off == end_off)
 210                 goto skip;
 211         size = fd->keylength + fd->entrylength;
 212
 213         do {
 214                 data_off = hfs_bnode_read_u16(node, rec_off);
 215                 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
 216                 rec_off -= 2;
 217         } while (rec_off >= end_off);
 218
 219         /* fill hole */
 220         hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
 221                        data_off - fd->keyoffset - size);
 222 skip:
 223         hfs_bnode_dump(node);
 224         if (!fd->record)
 225                 hfs_brec_update_parent(fd);
 226         return 0;
 227 }
 228
 229 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
 230 {
 231         struct hfs_btree *tree;
 232         struct hfs_bnode *node, *new_node;
 233         struct hfs_bnode_desc node_desc;
 234         int num_recs, new_rec_off, new_off, old_rec_off;
 235         int data_start, data_end, size;
 236
 237         tree = fd->tree;
 238         node = fd->bnode;
 239         new_node = hfs_bmap_alloc(tree);
 240         if (IS_ERR(new_node))
 241                 return new_node;
 242         hfs_bnode_get(node);
 243         dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
 244                 node->this, new_node->this, node->next);
 245         new_node->next = node->next;
 246         new_node->prev = node->this;
 247         new_node->parent = node->parent;
 248         new_node->type = node->type;
 249         new_node->height = node->height;
 250
 251         size = tree->node_size / 2 - node->num_recs * 2 - 14;
 252         old_rec_off = tree->node_size - 4;
 253         num_recs = 1;
 254         for (;;) {
 255                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 256                 if (data_start > size)
 257                         break;
 258                 old_rec_off -= 2;
 259                 if (++num_recs < node->num_recs)
 260                         continue;
 261                 /* panic? */
 262                 hfs_bnode_put(node);
 263                 hfs_bnode_put(new_node);
 264                 return ERR_PTR(-ENOSPC);
 265         }
 266
 267         if (fd->record + 1 < num_recs) {
 268                 /* new record is in the lower half,
 269                  * so leave some more space there
 270                  */
 271                 old_rec_off += 2;
 272                 num_recs--;
 273                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 274         } else {
 275                 hfs_bnode_put(node);
 276                 hfs_bnode_get(new_node);
 277                 fd->bnode = new_node;
 278                 fd->record -= num_recs;
 279                 fd->keyoffset -= data_start - 14;
 280                 fd->entryoffset -= data_start - 14;
 281         }
 282         new_node->num_recs = node->num_recs - num_recs;
 283         node->num_recs = num_recs;
 284
 285         new_rec_off = tree->node_size - 2;
 286         new_off = 14;
 287         size = data_start - new_off;
 288         num_recs = new_node->num_recs;
 289         data_end = data_start;
 290         while (num_recs) {
 291                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 292                 old_rec_off -= 2;
 293                 new_rec_off -= 2;
 294                 data_end = hfs_bnode_read_u16(node, old_rec_off);
 295                 new_off = data_end - size;
 296                 num_recs--;
 297         }
 298         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 299         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 300
 301         /* update new bnode header */
 302         node_desc.next = cpu_to_be32(new_node->next);
 303         node_desc.prev = cpu_to_be32(new_node->prev);
 304         node_desc.type = new_node->type;
 305         node_desc.height = new_node->height;
 306         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 307         node_desc.reserved = 0;
 308         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 309
 310         /* update previous bnode header */
 311         node->next = new_node->this;
 312         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 313         node_desc.next = cpu_to_be32(node->next);
 314         node_desc.num_recs = cpu_to_be16(node->num_recs);
 315         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 316
 317         /* update next bnode header */
 318         if (new_node->next) {
 319                 struct hfs_bnode *next_node = hfs_bnode_find(tree, new_node->next);
 320                 next_node->prev = new_node->this;
 321                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 322                 node_desc.prev = cpu_to_be32(next_node->prev);
 323                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 324                 hfs_bnode_put(next_node);
 325         } else if (node->this == tree->leaf_tail) {
 326                 /* if there is no next node, this might be the new tail */
 327                 tree->leaf_tail = new_node->this;
 328                 mark_inode_dirty(tree->inode);
 329         }
 330
 331         hfs_bnode_dump(node);
 332         hfs_bnode_dump(new_node);
 333         hfs_bnode_put(node);
 334
 335         return new_node;
 336 }
 337
 338 static int hfs_brec_update_parent(struct hfs_find_data *fd)
 339 {
 340         struct hfs_btree *tree;
 341         struct hfs_bnode *node, *new_node, *parent;
 342         int newkeylen, diff;
 343         int rec, rec_off, end_rec_off;
 344         int start_off, end_off;
 345
 346         tree = fd->tree;
 347         node = fd->bnode;
 348         new_node = NULL;
 349         if (!node->parent)
 350                 return 0;
 351
 352 again:
 353         parent = hfs_bnode_find(tree, node->parent);
 354         if (IS_ERR(parent))
 355                 return PTR_ERR(parent);
 356         __hfs_brec_find(parent, fd);
 357         hfs_bnode_dump(parent);
 358         rec = fd->record;
 359
 360         /* size difference between old and new key */
 361         if (tree->attributes & HFS_TREE_VARIDXKEYS)
 362                 newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
 363         else
 364                 fd->keylength = newkeylen = tree->max_key_len + 1;
 365         dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
 366
 367         rec_off = tree->node_size - (rec + 2) * 2;
 368         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 369         diff = newkeylen - fd->keylength;
 370         if (!diff)
 371                 goto skip;
 372         if (diff > 0) {
 373                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
 374                 if (end_rec_off - end_off < diff) {
 375
 376                         printk(KERN_DEBUG "hfs: splitting index node...\n");
 377                         fd->bnode = parent;
 378                         new_node = hfs_bnode_split(fd);
 379                         if (IS_ERR(new_node))
 380                                 return PTR_ERR(new_node);
 381                         parent = fd->bnode;
 382                         rec = fd->record;
 383                         rec_off = tree->node_size - (rec + 2) * 2;
 384                         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 385                 }
 386         }
 387
 388         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 389         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 390         start_off -= 4; /* move previous cnid too */
 391
 392         while (rec_off > end_rec_off) {
 393                 rec_off -= 2;
 394                 end_off = hfs_bnode_read_u16(parent, rec_off);
 395                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 396         }
 397         hfs_bnode_move(parent, start_off + diff, start_off,
 398                        end_off - start_off);
 399 skip:
 400         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 401         if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
 402                 hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
 403         hfs_bnode_dump(parent);
 404
 405         hfs_bnode_put(node);
 406         node = parent;
 407
 408         if (new_node) {
 409                 __be32 cnid;
 410
 411                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 412                 /* create index key and entry */
 413                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 414                 cnid = cpu_to_be32(new_node->this);
 415
 416                 __hfs_brec_find(fd->bnode, fd);
 417                 hfs_brec_insert(fd, &cnid, sizeof(cnid));
 418                 hfs_bnode_put(fd->bnode);
 419                 hfs_bnode_put(new_node);
 420
 421                 if (!rec) {
 422                         if (new_node == node)
 423                                 goto out;
 424                         /* restore search_key */
 425                         hfs_bnode_read_key(node, fd->search_key, 14);
 426                 }
 427         }
 428
 429         if (!rec && node->parent)
 430                 goto again;
 431 out:
 432         fd->bnode = node;
 433         return 0;
 434 }
 435
 436 static int hfs_btree_inc_height(struct hfs_btree *tree)
 437 {
 438         struct hfs_bnode *node, *new_node;
 439         struct hfs_bnode_desc node_desc;
 440         int key_size, rec;
 441         __be32 cnid;
 442
 443         node = NULL;
 444         if (tree->root) {
 445                 node = hfs_bnode_find(tree, tree->root);
 446                 if (IS_ERR(node))
 447                         return PTR_ERR(node);
 448         }
 449         new_node = hfs_bmap_alloc(tree);
 450         if (IS_ERR(new_node)) {
 451                 hfs_bnode_put(node);
 452                 return PTR_ERR(new_node);
 453         }
 454
 455         tree->root = new_node->this;
 456         if (!tree->depth) {
 457                 tree->leaf_head = tree->leaf_tail = new_node->this;
 458                 new_node->type = HFS_NODE_LEAF;
 459                 new_node->num_recs = 0;
 460         } else {
 461                 new_node->type = HFS_NODE_INDEX;
 462                 new_node->num_recs = 1;
 463         }
 464         new_node->parent = 0;
 465         new_node->next = 0;
 466         new_node->prev = 0;
 467         new_node->height = ++tree->depth;
 468
 469         node_desc.next = cpu_to_be32(new_node->next);
 470         node_desc.prev = cpu_to_be32(new_node->prev);
 471         node_desc.type = new_node->type;
 472         node_desc.height = new_node->height;
 473         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 474         node_desc.reserved = 0;
 475         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 476
 477         rec = tree->node_size - 2;
 478         hfs_bnode_write_u16(new_node, rec, 14);
 479
 480         if (node) {
 481                 /* insert old root idx into new root */
 482                 node->parent = tree->root;
 483                 if (node->type == HFS_NODE_LEAF ||
 484                     tree->attributes & HFS_TREE_VARIDXKEYS)
 485                         key_size = hfs_bnode_read_u8(node, 14) + 1;
 486                 else
 487                         key_size = tree->max_key_len + 1;
 488                 hfs_bnode_copy(new_node, 14, node, 14, key_size);
 489
 490                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
 491                         key_size = tree->max_key_len + 1;
 492                         hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
 493                 }
 494                 key_size = (key_size + 1) & -2;
 495                 cnid = cpu_to_be32(node->this);
 496                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 497
 498                 rec -= 2;
 499                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 500
 501                 hfs_bnode_put(node);
 502         }
 503         hfs_bnode_put(new_node);
 504         mark_inode_dirty(tree->inode);
 505
 506         return 0;
 507 }