kernel/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                                 pr_err("keylen %d too large\n", retval);
  51                                 retval = 0;
  52                         }
  53                 } else {
  54                         retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
  55                         if (retval > node->tree->max_key_len + 1) {
  56                                 pr_err("keylen %d too large\n", retval);
  57                                 retval = 0;
  58                         }
  59                 }
  60         }
  61         return retval;
  62 }
  63
  64 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  65 {
  66         struct hfs_btree *tree;
  67         struct hfs_bnode *node, *new_node;
  68         int size, key_len, rec;
  69         int data_off, end_off;
  70         int idx_rec_off, data_rec_off, end_rec_off;
  71         __be32 cnid;
  72
  73         tree = fd->tree;
  74         if (!fd->bnode) {
  75                 if (!tree->root)
  76                         hfs_btree_inc_height(tree);
  77                 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  78                 if (IS_ERR(fd->bnode))
  79                         return PTR_ERR(fd->bnode);
  80                 fd->record = -1;
  81         }
  82         new_node = NULL;
  83         key_len = (fd->search_key->key_len | 1) + 1;
  84 again:
  85         /* new record idx and complete record size */
  86         rec = fd->record + 1;
  87         size = key_len + entry_len;
  88
  89         node = fd->bnode;
  90         hfs_bnode_dump(node);
  91         /* get last offset */
  92         end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  93         end_off = hfs_bnode_read_u16(node, end_rec_off);
  94         end_rec_off -= 2;
  95         hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
  96                 rec, size, end_off, end_rec_off);
  97         if (size > end_rec_off - end_off) {
  98                 if (new_node)
  99                         panic("not enough room!\n");
 100                 new_node = hfs_bnode_split(fd);
 101                 if (IS_ERR(new_node))
 102                         return PTR_ERR(new_node);
 103                 goto again;
 104         }
 105         if (node->type == HFS_NODE_LEAF) {
 106                 tree->leaf_count++;
 107                 mark_inode_dirty(tree->inode);
 108         }
 109         node->num_recs++;
 110         /* write new last offset */
 111         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), 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         if (new_node) {
 135                 /* update parent key if we inserted a key
 136                  * at the start of the first node
 137                  */
 138                 if (!rec && new_node != node)
 139                         hfs_brec_update_parent(fd);
 140
 141                 hfs_bnode_put(fd->bnode);
 142                 if (!new_node->parent) {
 143                         hfs_btree_inc_height(tree);
 144                         new_node->parent = tree->root;
 145                 }
 146                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 147
 148                 /* create index data entry */
 149                 cnid = cpu_to_be32(new_node->this);
 150                 entry = &cnid;
 151                 entry_len = sizeof(cnid);
 152
 153                 /* get index key */
 154                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 155                 __hfs_brec_find(fd->bnode, fd);
 156
 157                 hfs_bnode_put(new_node);
 158                 new_node = NULL;
 159
 160                 if (tree->attributes & HFS_TREE_VARIDXKEYS)
 161                         key_len = fd->search_key->key_len + 1;
 162                 else {
 163                         fd->search_key->key_len = tree->max_key_len;
 164                         key_len = tree->max_key_len + 1;
 165                 }
 166                 goto again;
 167         }
 168
 169         if (!rec)
 170                 hfs_brec_update_parent(fd);
 171
 172         return 0;
 173 }
 174
 175 int hfs_brec_remove(struct hfs_find_data *fd)
 176 {
 177         struct hfs_btree *tree;
 178         struct hfs_bnode *node, *parent;
 179         int end_off, rec_off, data_off, size;
 180
 181         tree = fd->tree;
 182         node = fd->bnode;
 183 again:
 184         rec_off = tree->node_size - (fd->record + 2) * 2;
 185         end_off = tree->node_size - (node->num_recs + 1) * 2;
 186
 187         if (node->type == HFS_NODE_LEAF) {
 188                 tree->leaf_count--;
 189                 mark_inode_dirty(tree->inode);
 190         }
 191         hfs_bnode_dump(node);
 192         hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n",
 193                 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, *next_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         hfs_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         if (node->next)
 252                 next_node = hfs_bnode_find(tree, node->next);
 253         else
 254                 next_node = NULL;
 255
 256         if (IS_ERR(next_node)) {
 257                 hfs_bnode_put(node);
 258                 hfs_bnode_put(new_node);
 259                 return next_node;
 260         }
 261
 262         size = tree->node_size / 2 - node->num_recs * 2 - 14;
 263         old_rec_off = tree->node_size - 4;
 264         num_recs = 1;
 265         for (;;) {
 266                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 267                 if (data_start > size)
 268                         break;
 269                 old_rec_off -= 2;
 270                 if (++num_recs < node->num_recs)
 271                         continue;
 272                 /* panic? */
 273                 hfs_bnode_put(node);
 274                 hfs_bnode_put(new_node);
 275                 if (next_node)
 276                         hfs_bnode_put(next_node);
 277                 return ERR_PTR(-ENOSPC);
 278         }
 279
 280         if (fd->record + 1 < num_recs) {
 281                 /* new record is in the lower half,
 282                  * so leave some more space there
 283                  */
 284                 old_rec_off += 2;
 285                 num_recs--;
 286                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 287         } else {
 288                 hfs_bnode_put(node);
 289                 hfs_bnode_get(new_node);
 290                 fd->bnode = new_node;
 291                 fd->record -= num_recs;
 292                 fd->keyoffset -= data_start - 14;
 293                 fd->entryoffset -= data_start - 14;
 294         }
 295         new_node->num_recs = node->num_recs - num_recs;
 296         node->num_recs = num_recs;
 297
 298         new_rec_off = tree->node_size - 2;
 299         new_off = 14;
 300         size = data_start - new_off;
 301         num_recs = new_node->num_recs;
 302         data_end = data_start;
 303         while (num_recs) {
 304                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 305                 old_rec_off -= 2;
 306                 new_rec_off -= 2;
 307                 data_end = hfs_bnode_read_u16(node, old_rec_off);
 308                 new_off = data_end - size;
 309                 num_recs--;
 310         }
 311         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 312         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 313
 314         /* update new bnode header */
 315         node_desc.next = cpu_to_be32(new_node->next);
 316         node_desc.prev = cpu_to_be32(new_node->prev);
 317         node_desc.type = new_node->type;
 318         node_desc.height = new_node->height;
 319         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 320         node_desc.reserved = 0;
 321         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 322
 323         /* update previous bnode header */
 324         node->next = new_node->this;
 325         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 326         node_desc.next = cpu_to_be32(node->next);
 327         node_desc.num_recs = cpu_to_be16(node->num_recs);
 328         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 329
 330         /* update next bnode header */
 331         if (next_node) {
 332                 next_node->prev = new_node->this;
 333                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 334                 node_desc.prev = cpu_to_be32(next_node->prev);
 335                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 336                 hfs_bnode_put(next_node);
 337         } else if (node->this == tree->leaf_tail) {
 338                 /* if there is no next node, this might be the new tail */
 339                 tree->leaf_tail = new_node->this;
 340                 mark_inode_dirty(tree->inode);
 341         }
 342
 343         hfs_bnode_dump(node);
 344         hfs_bnode_dump(new_node);
 345         hfs_bnode_put(node);
 346
 347         return new_node;
 348 }
 349
 350 static int hfs_brec_update_parent(struct hfs_find_data *fd)
 351 {
 352         struct hfs_btree *tree;
 353         struct hfs_bnode *node, *new_node, *parent;
 354         int newkeylen, diff;
 355         int rec, rec_off, end_rec_off;
 356         int start_off, end_off;
 357
 358         tree = fd->tree;
 359         node = fd->bnode;
 360         new_node = NULL;
 361         if (!node->parent)
 362                 return 0;
 363
 364 again:
 365         parent = hfs_bnode_find(tree, node->parent);
 366         if (IS_ERR(parent))
 367                 return PTR_ERR(parent);
 368         __hfs_brec_find(parent, fd);
 369         hfs_bnode_dump(parent);
 370         rec = fd->record;
 371
 372         /* size difference between old and new key */
 373         if (tree->attributes & HFS_TREE_VARIDXKEYS)
 374                 newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
 375         else
 376                 fd->keylength = newkeylen = tree->max_key_len + 1;
 377         hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n",
 378                 rec, fd->keylength, newkeylen);
 379
 380         rec_off = tree->node_size - (rec + 2) * 2;
 381         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 382         diff = newkeylen - fd->keylength;
 383         if (!diff)
 384                 goto skip;
 385         if (diff > 0) {
 386                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
 387                 if (end_rec_off - end_off < diff) {
 388
 389                         printk(KERN_DEBUG "splitting index node...\n");
 390                         fd->bnode = parent;
 391                         new_node = hfs_bnode_split(fd);
 392                         if (IS_ERR(new_node))
 393                                 return PTR_ERR(new_node);
 394                         parent = fd->bnode;
 395                         rec = fd->record;
 396                         rec_off = tree->node_size - (rec + 2) * 2;
 397                         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 398                 }
 399         }
 400
 401         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 402         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 403         start_off -= 4; /* move previous cnid too */
 404
 405         while (rec_off > end_rec_off) {
 406                 rec_off -= 2;
 407                 end_off = hfs_bnode_read_u16(parent, rec_off);
 408                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 409         }
 410         hfs_bnode_move(parent, start_off + diff, start_off,
 411                        end_off - start_off);
 412 skip:
 413         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 414         if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
 415                 hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
 416         hfs_bnode_dump(parent);
 417
 418         hfs_bnode_put(node);
 419         node = parent;
 420
 421         if (new_node) {
 422                 __be32 cnid;
 423
 424                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 425                 /* create index key and entry */
 426                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 427                 cnid = cpu_to_be32(new_node->this);
 428
 429                 __hfs_brec_find(fd->bnode, fd);
 430                 hfs_brec_insert(fd, &cnid, sizeof(cnid));
 431                 hfs_bnode_put(fd->bnode);
 432                 hfs_bnode_put(new_node);
 433
 434                 if (!rec) {
 435                         if (new_node == node)
 436                                 goto out;
 437                         /* restore search_key */
 438                         hfs_bnode_read_key(node, fd->search_key, 14);
 439                 }
 440         }
 441
 442         if (!rec && node->parent)
 443                 goto again;
 444 out:
 445         fd->bnode = node;
 446         return 0;
 447 }
 448
 449 static int hfs_btree_inc_height(struct hfs_btree *tree)
 450 {
 451         struct hfs_bnode *node, *new_node;
 452         struct hfs_bnode_desc node_desc;
 453         int key_size, rec;
 454         __be32 cnid;
 455
 456         node = NULL;
 457         if (tree->root) {
 458                 node = hfs_bnode_find(tree, tree->root);
 459                 if (IS_ERR(node))
 460                         return PTR_ERR(node);
 461         }
 462         new_node = hfs_bmap_alloc(tree);
 463         if (IS_ERR(new_node)) {
 464                 hfs_bnode_put(node);
 465                 return PTR_ERR(new_node);
 466         }
 467
 468         tree->root = new_node->this;
 469         if (!tree->depth) {
 470                 tree->leaf_head = tree->leaf_tail = new_node->this;
 471                 new_node->type = HFS_NODE_LEAF;
 472                 new_node->num_recs = 0;
 473         } else {
 474                 new_node->type = HFS_NODE_INDEX;
 475                 new_node->num_recs = 1;
 476         }
 477         new_node->parent = 0;
 478         new_node->next = 0;
 479         new_node->prev = 0;
 480         new_node->height = ++tree->depth;
 481
 482         node_desc.next = cpu_to_be32(new_node->next);
 483         node_desc.prev = cpu_to_be32(new_node->prev);
 484         node_desc.type = new_node->type;
 485         node_desc.height = new_node->height;
 486         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 487         node_desc.reserved = 0;
 488         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 489
 490         rec = tree->node_size - 2;
 491         hfs_bnode_write_u16(new_node, rec, 14);
 492
 493         if (node) {
 494                 /* insert old root idx into new root */
 495                 node->parent = tree->root;
 496                 if (node->type == HFS_NODE_LEAF ||
 497                     tree->attributes & HFS_TREE_VARIDXKEYS)
 498                         key_size = hfs_bnode_read_u8(node, 14) + 1;
 499                 else
 500                         key_size = tree->max_key_len + 1;
 501                 hfs_bnode_copy(new_node, 14, node, 14, key_size);
 502
 503                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
 504                         key_size = tree->max_key_len + 1;
 505                         hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
 506                 }
 507                 key_size = (key_size + 1) & -2;
 508                 cnid = cpu_to_be32(node->this);
 509                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 510
 511                 rec -= 2;
 512                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 513
 514                 hfs_bnode_put(node);
 515         }
 516         hfs_bnode_put(new_node);
 517         mark_inode_dirty(tree->inode);
 518
 519         return 0;
 520 }