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, node->tree->node_size - (rec + 1) * 2);
  43                 if (!recoff)
  44                         return 0;
  45
  46                 retval = hfs_bnode_read_u16(node, recoff) + 2;
  47                 if (retval > node->tree->max_key_len + 2) {
  48                         printk(KERN_ERR "hfs: keylen %d too large\n",
  49                                 retval);
  50                         retval = 0;
  51                 }
  52         }
  53         return retval;
  54 }
  55
  56 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  57 {
  58         struct hfs_btree *tree;
  59         struct hfs_bnode *node, *new_node;
  60         int size, key_len, rec;
  61         int data_off, end_off;
  62         int idx_rec_off, data_rec_off, end_rec_off;
  63         __be32 cnid;
  64
  65         tree = fd->tree;
  66         if (!fd->bnode) {
  67                 if (!tree->root)
  68                         hfs_btree_inc_height(tree);
  69                 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  70                 if (IS_ERR(fd->bnode))
  71                         return PTR_ERR(fd->bnode);
  72                 fd->record = -1;
  73         }
  74         new_node = NULL;
  75         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
  76 again:
  77         /* new record idx and complete record size */
  78         rec = fd->record + 1;
  79         size = key_len + entry_len;
  80
  81         node = fd->bnode;
  82         hfs_bnode_dump(node);
  83         /* get last offset */
  84         end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  85         end_off = hfs_bnode_read_u16(node, end_rec_off);
  86         end_rec_off -= 2;
  87         dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
  88         if (size > end_rec_off - end_off) {
  89                 if (new_node)
  90                         panic("not enough room!\n");
  91                 new_node = hfs_bnode_split(fd);
  92                 if (IS_ERR(new_node))
  93                         return PTR_ERR(new_node);
  94                 goto again;
  95         }
  96         if (node->type == HFS_NODE_LEAF) {
  97                 tree->leaf_count++;
  98                 mark_inode_dirty(tree->inode);
  99         }
 100         node->num_recs++;
 101         /* write new last offset */
 102         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 103         hfs_bnode_write_u16(node, end_rec_off, end_off + size);
 104         data_off = end_off;
 105         data_rec_off = end_rec_off + 2;
 106         idx_rec_off = tree->node_size - (rec + 1) * 2;
 107         if (idx_rec_off == data_rec_off)
 108                 goto skip;
 109         /* move all following entries */
 110         do {
 111                 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
 112                 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
 113                 data_rec_off += 2;
 114         } while (data_rec_off < idx_rec_off);
 115
 116         /* move data away */
 117         hfs_bnode_move(node, data_off + size, data_off,
 118                        end_off - data_off);
 119
 120 skip:
 121         hfs_bnode_write(node, fd->search_key, data_off, key_len);
 122         hfs_bnode_write(node, entry, data_off + key_len, entry_len);
 123         hfs_bnode_dump(node);
 124
 125         if (new_node) {
 126                 /* update parent key if we inserted a key
 127                  * at the start of the first node
 128                  */
 129                 if (!rec && new_node != node)
 130                         hfs_brec_update_parent(fd);
 131
 132                 hfs_bnode_put(fd->bnode);
 133                 if (!new_node->parent) {
 134                         hfs_btree_inc_height(tree);
 135                         new_node->parent = tree->root;
 136                 }
 137                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 138
 139                 /* create index data entry */
 140                 cnid = cpu_to_be32(new_node->this);
 141                 entry = &cnid;
 142                 entry_len = sizeof(cnid);
 143
 144                 /* get index key */
 145                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 146                 __hfs_brec_find(fd->bnode, fd);
 147
 148                 hfs_bnode_put(new_node);
 149                 new_node = NULL;
 150
 151                 if (tree->attributes & HFS_TREE_VARIDXKEYS)
 152                         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
 153                 else {
 154                         fd->search_key->key_len = cpu_to_be16(tree->max_key_len);
 155                         key_len = tree->max_key_len + 2;
 156                 }
 157                 goto again;
 158         }
 159
 160         if (!rec)
 161                 hfs_brec_update_parent(fd);
 162
 163         return 0;
 164 }
 165
 166 int hfs_brec_remove(struct hfs_find_data *fd)
 167 {
 168         struct hfs_btree *tree;
 169         struct hfs_bnode *node, *parent;
 170         int end_off, rec_off, data_off, size;
 171
 172         tree = fd->tree;
 173         node = fd->bnode;
 174 again:
 175         rec_off = tree->node_size - (fd->record + 2) * 2;
 176         end_off = tree->node_size - (node->num_recs + 1) * 2;
 177
 178         if (node->type == HFS_NODE_LEAF) {
 179                 tree->leaf_count--;
 180                 mark_inode_dirty(tree->inode);
 181         }
 182         hfs_bnode_dump(node);
 183         dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", fd->record, fd->keylength + fd->entrylength);
 184         if (!--node->num_recs) {
 185                 hfs_bnode_unlink(node);
 186                 if (!node->parent)
 187                         return 0;
 188                 parent = hfs_bnode_find(tree, node->parent);
 189                 if (IS_ERR(parent))
 190                         return PTR_ERR(parent);
 191                 hfs_bnode_put(node);
 192                 node = fd->bnode = parent;
 193
 194                 __hfs_brec_find(node, fd);
 195                 goto again;
 196         }
 197         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 198
 199         if (rec_off == end_off)
 200                 goto skip;
 201         size = fd->keylength + fd->entrylength;
 202
 203         do {
 204                 data_off = hfs_bnode_read_u16(node, rec_off);
 205                 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
 206                 rec_off -= 2;
 207         } while (rec_off >= end_off);
 208
 209         /* fill hole */
 210         hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
 211                        data_off - fd->keyoffset - size);
 212 skip:
 213         hfs_bnode_dump(node);
 214         if (!fd->record)
 215                 hfs_brec_update_parent(fd);
 216         return 0;
 217 }
 218
 219 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
 220 {
 221         struct hfs_btree *tree;
 222         struct hfs_bnode *node, *new_node, *next_node;
 223         struct hfs_bnode_desc node_desc;
 224         int num_recs, new_rec_off, new_off, old_rec_off;
 225         int data_start, data_end, size;
 226
 227         tree = fd->tree;
 228         node = fd->bnode;
 229         new_node = hfs_bmap_alloc(tree);
 230         if (IS_ERR(new_node))
 231                 return new_node;
 232         hfs_bnode_get(node);
 233         dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
 234                 node->this, new_node->this, node->next);
 235         new_node->next = node->next;
 236         new_node->prev = node->this;
 237         new_node->parent = node->parent;
 238         new_node->type = node->type;
 239         new_node->height = node->height;
 240
 241         if (node->next)
 242                 next_node = hfs_bnode_find(tree, node->next);
 243         else
 244                 next_node = NULL;
 245
 246         if (IS_ERR(next_node)) {
 247                 hfs_bnode_put(node);
 248                 hfs_bnode_put(new_node);
 249                 return next_node;
 250         }
 251
 252         size = tree->node_size / 2 - node->num_recs * 2 - 14;
 253         old_rec_off = tree->node_size - 4;
 254         num_recs = 1;
 255         for (;;) {
 256                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 257                 if (data_start > size)
 258                         break;
 259                 old_rec_off -= 2;
 260                 if (++num_recs < node->num_recs)
 261                         continue;
 262                 /* panic? */
 263                 hfs_bnode_put(node);
 264                 hfs_bnode_put(new_node);
 265                 if (next_node)
 266                         hfs_bnode_put(next_node);
 267                 return ERR_PTR(-ENOSPC);
 268         }
 269
 270         if (fd->record + 1 < num_recs) {
 271                 /* new record is in the lower half,
 272                  * so leave some more space there
 273                  */
 274                 old_rec_off += 2;
 275                 num_recs--;
 276                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 277         } else {
 278                 hfs_bnode_put(node);
 279                 hfs_bnode_get(new_node);
 280                 fd->bnode = new_node;
 281                 fd->record -= num_recs;
 282                 fd->keyoffset -= data_start - 14;
 283                 fd->entryoffset -= data_start - 14;
 284         }
 285         new_node->num_recs = node->num_recs - num_recs;
 286         node->num_recs = num_recs;
 287
 288         new_rec_off = tree->node_size - 2;
 289         new_off = 14;
 290         size = data_start - new_off;
 291         num_recs = new_node->num_recs;
 292         data_end = data_start;
 293         while (num_recs) {
 294                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 295                 old_rec_off -= 2;
 296                 new_rec_off -= 2;
 297                 data_end = hfs_bnode_read_u16(node, old_rec_off);
 298                 new_off = data_end - size;
 299                 num_recs--;
 300         }
 301         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 302         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 303
 304         /* update new bnode header */
 305         node_desc.next = cpu_to_be32(new_node->next);
 306         node_desc.prev = cpu_to_be32(new_node->prev);
 307         node_desc.type = new_node->type;
 308         node_desc.height = new_node->height;
 309         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 310         node_desc.reserved = 0;
 311         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 312
 313         /* update previous bnode header */
 314         node->next = new_node->this;
 315         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 316         node_desc.next = cpu_to_be32(node->next);
 317         node_desc.num_recs = cpu_to_be16(node->num_recs);
 318         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 319
 320         /* update next bnode header */
 321         if (next_node) {
 322                 next_node->prev = new_node->this;
 323                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 324                 node_desc.prev = cpu_to_be32(next_node->prev);
 325                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 326                 hfs_bnode_put(next_node);
 327         } else if (node->this == tree->leaf_tail) {
 328                 /* if there is no next node, this might be the new tail */
 329                 tree->leaf_tail = new_node->this;
 330                 mark_inode_dirty(tree->inode);
 331         }
 332
 333         hfs_bnode_dump(node);
 334         hfs_bnode_dump(new_node);
 335         hfs_bnode_put(node);
 336
 337         return new_node;
 338 }
 339
 340 static int hfs_brec_update_parent(struct hfs_find_data *fd)
 341 {
 342         struct hfs_btree *tree;
 343         struct hfs_bnode *node, *new_node, *parent;
 344         int newkeylen, diff;
 345         int rec, rec_off, end_rec_off;
 346         int start_off, end_off;
 347
 348         tree = fd->tree;
 349         node = fd->bnode;
 350         new_node = NULL;
 351         if (!node->parent)
 352                 return 0;
 353
 354 again:
 355         parent = hfs_bnode_find(tree, node->parent);
 356         if (IS_ERR(parent))
 357                 return PTR_ERR(parent);
 358         __hfs_brec_find(parent, fd);
 359         hfs_bnode_dump(parent);
 360         rec = fd->record;
 361
 362         /* size difference between old and new key */
 363         if (tree->attributes & HFS_TREE_VARIDXKEYS)
 364                 newkeylen = hfs_bnode_read_u16(node, 14) + 2;
 365         else
 366                 fd->keylength = newkeylen = tree->max_key_len + 2;
 367         dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
 368
 369         rec_off = tree->node_size - (rec + 2) * 2;
 370         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 371         diff = newkeylen - fd->keylength;
 372         if (!diff)
 373                 goto skip;
 374         if (diff > 0) {
 375                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
 376                 if (end_rec_off - end_off < diff) {
 377
 378                         printk(KERN_DEBUG "hfs: splitting index node...\n");
 379                         fd->bnode = parent;
 380                         new_node = hfs_bnode_split(fd);
 381                         if (IS_ERR(new_node))
 382                                 return PTR_ERR(new_node);
 383                         parent = fd->bnode;
 384                         rec = fd->record;
 385                         rec_off = tree->node_size - (rec + 2) * 2;
 386                         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 387                 }
 388         }
 389
 390         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 391         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 392         start_off -= 4; /* move previous cnid too */
 393
 394         while (rec_off > end_rec_off) {
 395                 rec_off -= 2;
 396                 end_off = hfs_bnode_read_u16(parent, rec_off);
 397                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 398         }
 399         hfs_bnode_move(parent, start_off + diff, start_off,
 400                        end_off - start_off);
 401 skip:
 402         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 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_u16(node, 14) + 2;
 486                 else
 487                         key_size = tree->max_key_len + 2;
 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 + 2;
 492                         hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
 493                 }
 494                 cnid = cpu_to_be32(node->this);
 495                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 496
 497                 rec -= 2;
 498                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 499
 500                 hfs_bnode_put(node);
 501         }
 502         hfs_bnode_put(new_node);
 503         mark_inode_dirty(tree->inode);
 504
 505         return 0;
 506 }