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                 if (node->tree->attributes & HFS_TREE_BIGKEYS)
  46                         retval = hfs_bnode_read_u16(node, recoff) + 2;
  47                 else
  48                         retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
  49         }
  50         return retval;
  51 }
  52
  53 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  54 {
  55         struct hfs_btree *tree;
  56         struct hfs_bnode *node, *new_node;
  57         int size, key_len, rec;
  58         int data_off, end_off;
  59         int idx_rec_off, data_rec_off, end_rec_off;
  60         __be32 cnid;
  61
  62         tree = fd->tree;
  63         if (!fd->bnode) {
  64                 if (!tree->root)
  65                         hfs_btree_inc_height(tree);
  66                 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  67                 if (IS_ERR(fd->bnode))
  68                         return PTR_ERR(fd->bnode);
  69                 fd->record = -1;
  70         }
  71         new_node = NULL;
  72         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
  73 again:
  74         /* new record idx and complete record size */
  75         rec = fd->record + 1;
  76         size = key_len + entry_len;
  77
  78         node = fd->bnode;
  79         hfs_bnode_dump(node);
  80         /* get last offset */
  81         end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  82         end_off = hfs_bnode_read_u16(node, end_rec_off);
  83         end_rec_off -= 2;
  84         dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
  85         if (size > end_rec_off - end_off) {
  86                 if (new_node)
  87                         panic("not enough room!\n");
  88                 new_node = hfs_bnode_split(fd);
  89                 if (IS_ERR(new_node))
  90                         return PTR_ERR(new_node);
  91                 goto again;
  92         }
  93         if (node->type == HFS_NODE_LEAF) {
  94                 tree->leaf_count++;
  95                 mark_inode_dirty(tree->inode);
  96         }
  97         node->num_recs++;
  98         /* write new last offset */
  99         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 100         hfs_bnode_write_u16(node, end_rec_off, end_off + size);
 101         data_off = end_off;
 102         data_rec_off = end_rec_off + 2;
 103         idx_rec_off = tree->node_size - (rec + 1) * 2;
 104         if (idx_rec_off == data_rec_off)
 105                 goto skip;
 106         /* move all following entries */
 107         do {
 108                 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
 109                 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
 110                 data_rec_off += 2;
 111         } while (data_rec_off < idx_rec_off);
 112
 113         /* move data away */
 114         hfs_bnode_move(node, data_off + size, data_off,
 115                        end_off - data_off);
 116
 117 skip:
 118         hfs_bnode_write(node, fd->search_key, data_off, key_len);
 119         hfs_bnode_write(node, entry, data_off + key_len, entry_len);
 120         hfs_bnode_dump(node);
 121
 122         if (new_node) {
 123                 /* update parent key if we inserted a key
 124                  * at the start of the first node
 125                  */
 126                 if (!rec && new_node != node)
 127                         hfs_brec_update_parent(fd);
 128
 129                 hfs_bnode_put(fd->bnode);
 130                 if (!new_node->parent) {
 131                         hfs_btree_inc_height(tree);
 132                         new_node->parent = tree->root;
 133                 }
 134                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 135
 136                 /* create index data entry */
 137                 cnid = cpu_to_be32(new_node->this);
 138                 entry = &cnid;
 139                 entry_len = sizeof(cnid);
 140
 141                 /* get index key */
 142                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 143                 __hfs_brec_find(fd->bnode, fd);
 144
 145                 hfs_bnode_put(new_node);
 146                 new_node = NULL;
 147
 148                 if (tree->attributes & HFS_TREE_VARIDXKEYS)
 149                         key_len = be16_to_cpu(fd->search_key->key_len) + 2;
 150                 else {
 151                         fd->search_key->key_len = cpu_to_be16(tree->max_key_len);
 152                         key_len = tree->max_key_len + 2;
 153                 }
 154                 goto again;
 155         }
 156
 157         if (!rec)
 158                 hfs_brec_update_parent(fd);
 159
 160         return 0;
 161 }
 162
 163 int hfs_brec_remove(struct hfs_find_data *fd)
 164 {
 165         struct hfs_btree *tree;
 166         struct hfs_bnode *node, *parent;
 167         int end_off, rec_off, data_off, size;
 168
 169         tree = fd->tree;
 170         node = fd->bnode;
 171 again:
 172         rec_off = tree->node_size - (fd->record + 2) * 2;
 173         end_off = tree->node_size - (node->num_recs + 1) * 2;
 174
 175         if (node->type == HFS_NODE_LEAF) {
 176                 tree->leaf_count--;
 177                 mark_inode_dirty(tree->inode);
 178         }
 179         hfs_bnode_dump(node);
 180         dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", fd->record, fd->keylength + fd->entrylength);
 181         if (!--node->num_recs) {
 182                 hfs_bnode_unlink(node);
 183                 if (!node->parent)
 184                         return 0;
 185                 parent = hfs_bnode_find(tree, node->parent);
 186                 if (IS_ERR(parent))
 187                         return PTR_ERR(parent);
 188                 hfs_bnode_put(node);
 189                 node = fd->bnode = parent;
 190
 191                 __hfs_brec_find(node, fd);
 192                 goto again;
 193         }
 194         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 195
 196         if (rec_off == end_off)
 197                 goto skip;
 198         size = fd->keylength + fd->entrylength;
 199
 200         do {
 201                 data_off = hfs_bnode_read_u16(node, rec_off);
 202                 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
 203                 rec_off -= 2;
 204         } while (rec_off >= end_off);
 205
 206         /* fill hole */
 207         hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
 208                        data_off - fd->keyoffset - size);
 209 skip:
 210         hfs_bnode_dump(node);
 211         if (!fd->record)
 212                 hfs_brec_update_parent(fd);
 213         return 0;
 214 }
 215
 216 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
 217 {
 218         struct hfs_btree *tree;
 219         struct hfs_bnode *node, *new_node;
 220         struct hfs_bnode_desc node_desc;
 221         int num_recs, new_rec_off, new_off, old_rec_off;
 222         int data_start, data_end, size;
 223
 224         tree = fd->tree;
 225         node = fd->bnode;
 226         new_node = hfs_bmap_alloc(tree);
 227         if (IS_ERR(new_node))
 228                 return new_node;
 229         hfs_bnode_get(node);
 230         dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
 231                 node->this, new_node->this, node->next);
 232         new_node->next = node->next;
 233         new_node->prev = node->this;
 234         new_node->parent = node->parent;
 235         new_node->type = node->type;
 236         new_node->height = node->height;
 237
 238         size = tree->node_size / 2 - node->num_recs * 2 - 14;
 239         old_rec_off = tree->node_size - 4;
 240         num_recs = 1;
 241         for (;;) {
 242                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 243                 if (data_start > size)
 244                         break;
 245                 old_rec_off -= 2;
 246                 if (++num_recs < node->num_recs)
 247                         continue;
 248                 /* panic? */
 249                 hfs_bnode_put(node);
 250                 hfs_bnode_put(new_node);
 251                 return ERR_PTR(-ENOSPC);
 252         }
 253
 254         if (fd->record + 1 < num_recs) {
 255                 /* new record is in the lower half,
 256                  * so leave some more space there
 257                  */
 258                 old_rec_off += 2;
 259                 num_recs--;
 260                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 261         } else {
 262                 hfs_bnode_put(node);
 263                 hfs_bnode_get(new_node);
 264                 fd->bnode = new_node;
 265                 fd->record -= num_recs;
 266                 fd->keyoffset -= data_start - 14;
 267                 fd->entryoffset -= data_start - 14;
 268         }
 269         new_node->num_recs = node->num_recs - num_recs;
 270         node->num_recs = num_recs;
 271
 272         new_rec_off = tree->node_size - 2;
 273         new_off = 14;
 274         size = data_start - new_off;
 275         num_recs = new_node->num_recs;
 276         data_end = data_start;
 277         while (num_recs) {
 278                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 279                 old_rec_off -= 2;
 280                 new_rec_off -= 2;
 281                 data_end = hfs_bnode_read_u16(node, old_rec_off);
 282                 new_off = data_end - size;
 283                 num_recs--;
 284         }
 285         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 286         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 287
 288         /* update new bnode header */
 289         node_desc.next = cpu_to_be32(new_node->next);
 290         node_desc.prev = cpu_to_be32(new_node->prev);
 291         node_desc.type = new_node->type;
 292         node_desc.height = new_node->height;
 293         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 294         node_desc.reserved = 0;
 295         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 296
 297         /* update previous bnode header */
 298         node->next = new_node->this;
 299         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 300         node_desc.next = cpu_to_be32(node->next);
 301         node_desc.num_recs = cpu_to_be16(node->num_recs);
 302         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 303
 304         /* update next bnode header */
 305         if (new_node->next) {
 306                 struct hfs_bnode *next_node = hfs_bnode_find(tree, new_node->next);
 307                 next_node->prev = new_node->this;
 308                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 309                 node_desc.prev = cpu_to_be32(next_node->prev);
 310                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 311                 hfs_bnode_put(next_node);
 312         } else if (node->this == tree->leaf_tail) {
 313                 /* if there is no next node, this might be the new tail */
 314                 tree->leaf_tail = new_node->this;
 315                 mark_inode_dirty(tree->inode);
 316         }
 317
 318         hfs_bnode_dump(node);
 319         hfs_bnode_dump(new_node);
 320         hfs_bnode_put(node);
 321
 322         return new_node;
 323 }
 324
 325 static int hfs_brec_update_parent(struct hfs_find_data *fd)
 326 {
 327         struct hfs_btree *tree;
 328         struct hfs_bnode *node, *new_node, *parent;
 329         int newkeylen, diff;
 330         int rec, rec_off, end_rec_off;
 331         int start_off, end_off;
 332
 333         tree = fd->tree;
 334         node = fd->bnode;
 335         new_node = NULL;
 336         if (!node->parent)
 337                 return 0;
 338
 339 again:
 340         parent = hfs_bnode_find(tree, node->parent);
 341         if (IS_ERR(parent))
 342                 return PTR_ERR(parent);
 343         __hfs_brec_find(parent, fd);
 344         hfs_bnode_dump(parent);
 345         rec = fd->record;
 346
 347         /* size difference between old and new key */
 348         if (tree->attributes & HFS_TREE_VARIDXKEYS)
 349                 newkeylen = hfs_bnode_read_u16(node, 14) + 2;
 350         else
 351                 fd->keylength = newkeylen = tree->max_key_len + 2;
 352         dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
 353
 354         rec_off = tree->node_size - (rec + 2) * 2;
 355         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 356         diff = newkeylen - fd->keylength;
 357         if (!diff)
 358                 goto skip;
 359         if (diff > 0) {
 360                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
 361                 if (end_rec_off - end_off < diff) {
 362
 363                         printk(KERN_DEBUG "hfs: splitting index node...\n");
 364                         fd->bnode = parent;
 365                         new_node = hfs_bnode_split(fd);
 366                         if (IS_ERR(new_node))
 367                                 return PTR_ERR(new_node);
 368                         parent = fd->bnode;
 369                         rec = fd->record;
 370                         rec_off = tree->node_size - (rec + 2) * 2;
 371                         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 372                 }
 373         }
 374
 375         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 376         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 377         start_off -= 4; /* move previous cnid too */
 378
 379         while (rec_off > end_rec_off) {
 380                 rec_off -= 2;
 381                 end_off = hfs_bnode_read_u16(parent, rec_off);
 382                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 383         }
 384         hfs_bnode_move(parent, start_off + diff, start_off,
 385                        end_off - start_off);
 386 skip:
 387         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 388         hfs_bnode_dump(parent);
 389
 390         hfs_bnode_put(node);
 391         node = parent;
 392
 393         if (new_node) {
 394                 __be32 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 static 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         __be32 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_u16(node, 14) + 2;
 471                 else
 472                         key_size = tree->max_key_len + 2;
 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 + 2;
 477                         hfs_bnode_write_u16(new_node, 14, tree->max_key_len);
 478                 }
 479                 cnid = cpu_to_be32(node->this);
 480                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 481
 482                 rec -= 2;
 483                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 484
 485                 hfs_bnode_put(node);
 486         }
 487         hfs_bnode_put(new_node);
 488         mark_inode_dirty(tree->inode);
 489
 490         return 0;
 491 }