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                 else
  50                         retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
  51         }
  52         return retval;
  53 }
  54
  55 int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
  56 {
  57         struct hfs_btree *tree;
  58         struct hfs_bnode *node, *new_node;
  59         int size, key_len, rec;
  60         int data_off, end_off;
  61         int idx_rec_off, data_rec_off, end_rec_off;
  62         __be32 cnid;
  63
  64         tree = fd->tree;
  65         if (!fd->bnode) {
  66                 if (!tree->root)
  67                         hfs_btree_inc_height(tree);
  68                 fd->bnode = hfs_bnode_find(tree, tree->leaf_head);
  69                 if (IS_ERR(fd->bnode))
  70                         return PTR_ERR(fd->bnode);
  71                 fd->record = -1;
  72         }
  73         new_node = NULL;
  74         key_len = (fd->search_key->key_len | 1) + 1;
  75 again:
  76         /* new record idx and complete record size */
  77         rec = fd->record + 1;
  78         size = key_len + entry_len;
  79
  80         node = fd->bnode;
  81         hfs_bnode_dump(node);
  82         /* get last offset */
  83         end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
  84         end_off = hfs_bnode_read_u16(node, end_rec_off);
  85         end_rec_off -= 2;
  86         dprint(DBG_BNODE_MOD, "insert_rec: %d, %d, %d, %d\n", rec, size, end_off, end_rec_off);
  87         if (size > end_rec_off - end_off) {
  88                 if (new_node)
  89                         panic("not enough room!\n");
  90                 new_node = hfs_bnode_split(fd);
  91                 if (IS_ERR(new_node))
  92                         return PTR_ERR(new_node);
  93                 goto again;
  94         }
  95         if (node->type == HFS_NODE_LEAF) {
  96                 tree->leaf_count++;
  97                 mark_inode_dirty(tree->inode);
  98         }
  99         node->num_recs++;
 100         /* write new last offset */
 101         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 102         hfs_bnode_write_u16(node, end_rec_off, end_off + size);
 103         data_off = end_off;
 104         data_rec_off = end_rec_off + 2;
 105         idx_rec_off = tree->node_size - (rec + 1) * 2;
 106         if (idx_rec_off == data_rec_off)
 107                 goto skip;
 108         /* move all following entries */
 109         do {
 110                 data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
 111                 hfs_bnode_write_u16(node, data_rec_off, data_off + size);
 112                 data_rec_off += 2;
 113         } while (data_rec_off < idx_rec_off);
 114
 115         /* move data away */
 116         hfs_bnode_move(node, data_off + size, data_off,
 117                        end_off - data_off);
 118
 119 skip:
 120         hfs_bnode_write(node, fd->search_key, data_off, key_len);
 121         hfs_bnode_write(node, entry, data_off + key_len, entry_len);
 122         hfs_bnode_dump(node);
 123
 124         if (new_node) {
 125                 /* update parent key if we inserted a key
 126                  * at the start of the first node
 127                  */
 128                 if (!rec && new_node != node)
 129                         hfs_brec_update_parent(fd);
 130
 131                 hfs_bnode_put(fd->bnode);
 132                 if (!new_node->parent) {
 133                         hfs_btree_inc_height(tree);
 134                         new_node->parent = tree->root;
 135                 }
 136                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 137
 138                 /* create index data entry */
 139                 cnid = cpu_to_be32(new_node->this);
 140                 entry = &cnid;
 141                 entry_len = sizeof(cnid);
 142
 143                 /* get index key */
 144                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 145                 __hfs_brec_find(fd->bnode, fd);
 146
 147                 hfs_bnode_put(new_node);
 148                 new_node = NULL;
 149
 150                 if (tree->attributes & HFS_TREE_VARIDXKEYS)
 151                         key_len = fd->search_key->key_len + 1;
 152                 else {
 153                         fd->search_key->key_len = tree->max_key_len;
 154                         key_len = tree->max_key_len + 1;
 155                 }
 156                 goto again;
 157         }
 158
 159         if (!rec)
 160                 hfs_brec_update_parent(fd);
 161
 162         return 0;
 163 }
 164
 165 int hfs_brec_remove(struct hfs_find_data *fd)
 166 {
 167         struct hfs_btree *tree;
 168         struct hfs_bnode *node, *parent;
 169         int end_off, rec_off, data_off, size;
 170
 171         tree = fd->tree;
 172         node = fd->bnode;
 173 again:
 174         rec_off = tree->node_size - (fd->record + 2) * 2;
 175         end_off = tree->node_size - (node->num_recs + 1) * 2;
 176
 177         if (node->type == HFS_NODE_LEAF) {
 178                 tree->leaf_count--;
 179                 mark_inode_dirty(tree->inode);
 180         }
 181         hfs_bnode_dump(node);
 182         dprint(DBG_BNODE_MOD, "remove_rec: %d, %d\n", fd->record, fd->keylength + fd->entrylength);
 183         if (!--node->num_recs) {
 184                 hfs_bnode_unlink(node);
 185                 if (!node->parent)
 186                         return 0;
 187                 parent = hfs_bnode_find(tree, node->parent);
 188                 if (IS_ERR(parent))
 189                         return PTR_ERR(parent);
 190                 hfs_bnode_put(node);
 191                 node = fd->bnode = parent;
 192
 193                 __hfs_brec_find(node, fd);
 194                 goto again;
 195         }
 196         hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
 197
 198         if (rec_off == end_off)
 199                 goto skip;
 200         size = fd->keylength + fd->entrylength;
 201
 202         do {
 203                 data_off = hfs_bnode_read_u16(node, rec_off);
 204                 hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
 205                 rec_off -= 2;
 206         } while (rec_off >= end_off);
 207
 208         /* fill hole */
 209         hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
 210                        data_off - fd->keyoffset - size);
 211 skip:
 212         hfs_bnode_dump(node);
 213         if (!fd->record)
 214                 hfs_brec_update_parent(fd);
 215         return 0;
 216 }
 217
 218 static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
 219 {
 220         struct hfs_btree *tree;
 221         struct hfs_bnode *node, *new_node;
 222         struct hfs_bnode_desc node_desc;
 223         int num_recs, new_rec_off, new_off, old_rec_off;
 224         int data_start, data_end, size;
 225
 226         tree = fd->tree;
 227         node = fd->bnode;
 228         new_node = hfs_bmap_alloc(tree);
 229         if (IS_ERR(new_node))
 230                 return new_node;
 231         hfs_bnode_get(node);
 232         dprint(DBG_BNODE_MOD, "split_nodes: %d - %d - %d\n",
 233                 node->this, new_node->this, node->next);
 234         new_node->next = node->next;
 235         new_node->prev = node->this;
 236         new_node->parent = node->parent;
 237         new_node->type = node->type;
 238         new_node->height = node->height;
 239
 240         size = tree->node_size / 2 - node->num_recs * 2 - 14;
 241         old_rec_off = tree->node_size - 4;
 242         num_recs = 1;
 243         for (;;) {
 244                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 245                 if (data_start > size)
 246                         break;
 247                 old_rec_off -= 2;
 248                 if (++num_recs < node->num_recs)
 249                         continue;
 250                 /* panic? */
 251                 hfs_bnode_put(node);
 252                 hfs_bnode_put(new_node);
 253                 return ERR_PTR(-ENOSPC);
 254         }
 255
 256         if (fd->record + 1 < num_recs) {
 257                 /* new record is in the lower half,
 258                  * so leave some more space there
 259                  */
 260                 old_rec_off += 2;
 261                 num_recs--;
 262                 data_start = hfs_bnode_read_u16(node, old_rec_off);
 263         } else {
 264                 hfs_bnode_put(node);
 265                 hfs_bnode_get(new_node);
 266                 fd->bnode = new_node;
 267                 fd->record -= num_recs;
 268                 fd->keyoffset -= data_start - 14;
 269                 fd->entryoffset -= data_start - 14;
 270         }
 271         new_node->num_recs = node->num_recs - num_recs;
 272         node->num_recs = num_recs;
 273
 274         new_rec_off = tree->node_size - 2;
 275         new_off = 14;
 276         size = data_start - new_off;
 277         num_recs = new_node->num_recs;
 278         data_end = data_start;
 279         while (num_recs) {
 280                 hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 281                 old_rec_off -= 2;
 282                 new_rec_off -= 2;
 283                 data_end = hfs_bnode_read_u16(node, old_rec_off);
 284                 new_off = data_end - size;
 285                 num_recs--;
 286         }
 287         hfs_bnode_write_u16(new_node, new_rec_off, new_off);
 288         hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
 289
 290         /* update new bnode header */
 291         node_desc.next = cpu_to_be32(new_node->next);
 292         node_desc.prev = cpu_to_be32(new_node->prev);
 293         node_desc.type = new_node->type;
 294         node_desc.height = new_node->height;
 295         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 296         node_desc.reserved = 0;
 297         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 298
 299         /* update previous bnode header */
 300         node->next = new_node->this;
 301         hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
 302         node_desc.next = cpu_to_be32(node->next);
 303         node_desc.num_recs = cpu_to_be16(node->num_recs);
 304         hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
 305
 306         /* update next bnode header */
 307         if (new_node->next) {
 308                 struct hfs_bnode *next_node = hfs_bnode_find(tree, new_node->next);
 309                 next_node->prev = new_node->this;
 310                 hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
 311                 node_desc.prev = cpu_to_be32(next_node->prev);
 312                 hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
 313                 hfs_bnode_put(next_node);
 314         } else if (node->this == tree->leaf_tail) {
 315                 /* if there is no next node, this might be the new tail */
 316                 tree->leaf_tail = new_node->this;
 317                 mark_inode_dirty(tree->inode);
 318         }
 319
 320         hfs_bnode_dump(node);
 321         hfs_bnode_dump(new_node);
 322         hfs_bnode_put(node);
 323
 324         return new_node;
 325 }
 326
 327 static int hfs_brec_update_parent(struct hfs_find_data *fd)
 328 {
 329         struct hfs_btree *tree;
 330         struct hfs_bnode *node, *new_node, *parent;
 331         int newkeylen, diff;
 332         int rec, rec_off, end_rec_off;
 333         int start_off, end_off;
 334
 335         tree = fd->tree;
 336         node = fd->bnode;
 337         new_node = NULL;
 338         if (!node->parent)
 339                 return 0;
 340
 341 again:
 342         parent = hfs_bnode_find(tree, node->parent);
 343         if (IS_ERR(parent))
 344                 return PTR_ERR(parent);
 345         __hfs_brec_find(parent, fd);
 346         hfs_bnode_dump(parent);
 347         rec = fd->record;
 348
 349         /* size difference between old and new key */
 350         if (tree->attributes & HFS_TREE_VARIDXKEYS)
 351                 newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
 352         else
 353                 fd->keylength = newkeylen = tree->max_key_len + 1;
 354         dprint(DBG_BNODE_MOD, "update_rec: %d, %d, %d\n", rec, fd->keylength, newkeylen);
 355
 356         rec_off = tree->node_size - (rec + 2) * 2;
 357         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 358         diff = newkeylen - fd->keylength;
 359         if (!diff)
 360                 goto skip;
 361         if (diff > 0) {
 362                 end_off = hfs_bnode_read_u16(parent, end_rec_off);
 363                 if (end_rec_off - end_off < diff) {
 364
 365                         printk(KERN_DEBUG "hfs: splitting index node...\n");
 366                         fd->bnode = parent;
 367                         new_node = hfs_bnode_split(fd);
 368                         if (IS_ERR(new_node))
 369                                 return PTR_ERR(new_node);
 370                         parent = fd->bnode;
 371                         rec = fd->record;
 372                         rec_off = tree->node_size - (rec + 2) * 2;
 373                         end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
 374                 }
 375         }
 376
 377         end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
 378         hfs_bnode_write_u16(parent, rec_off, start_off + diff);
 379         start_off -= 4; /* move previous cnid too */
 380
 381         while (rec_off > end_rec_off) {
 382                 rec_off -= 2;
 383                 end_off = hfs_bnode_read_u16(parent, rec_off);
 384                 hfs_bnode_write_u16(parent, rec_off, end_off + diff);
 385         }
 386         hfs_bnode_move(parent, start_off + diff, start_off,
 387                        end_off - start_off);
 388 skip:
 389         hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
 390         if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
 391                 hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
 392         hfs_bnode_dump(parent);
 393
 394         hfs_bnode_put(node);
 395         node = parent;
 396
 397         if (new_node) {
 398                 __be32 cnid;
 399
 400                 fd->bnode = hfs_bnode_find(tree, new_node->parent);
 401                 /* create index key and entry */
 402                 hfs_bnode_read_key(new_node, fd->search_key, 14);
 403                 cnid = cpu_to_be32(new_node->this);
 404
 405                 __hfs_brec_find(fd->bnode, fd);
 406                 hfs_brec_insert(fd, &cnid, sizeof(cnid));
 407                 hfs_bnode_put(fd->bnode);
 408                 hfs_bnode_put(new_node);
 409
 410                 if (!rec) {
 411                         if (new_node == node)
 412                                 goto out;
 413                         /* restore search_key */
 414                         hfs_bnode_read_key(node, fd->search_key, 14);
 415                 }
 416         }
 417
 418         if (!rec && node->parent)
 419                 goto again;
 420 out:
 421         fd->bnode = node;
 422         return 0;
 423 }
 424
 425 static int hfs_btree_inc_height(struct hfs_btree *tree)
 426 {
 427         struct hfs_bnode *node, *new_node;
 428         struct hfs_bnode_desc node_desc;
 429         int key_size, rec;
 430         __be32 cnid;
 431
 432         node = NULL;
 433         if (tree->root) {
 434                 node = hfs_bnode_find(tree, tree->root);
 435                 if (IS_ERR(node))
 436                         return PTR_ERR(node);
 437         }
 438         new_node = hfs_bmap_alloc(tree);
 439         if (IS_ERR(new_node)) {
 440                 hfs_bnode_put(node);
 441                 return PTR_ERR(new_node);
 442         }
 443
 444         tree->root = new_node->this;
 445         if (!tree->depth) {
 446                 tree->leaf_head = tree->leaf_tail = new_node->this;
 447                 new_node->type = HFS_NODE_LEAF;
 448                 new_node->num_recs = 0;
 449         } else {
 450                 new_node->type = HFS_NODE_INDEX;
 451                 new_node->num_recs = 1;
 452         }
 453         new_node->parent = 0;
 454         new_node->next = 0;
 455         new_node->prev = 0;
 456         new_node->height = ++tree->depth;
 457
 458         node_desc.next = cpu_to_be32(new_node->next);
 459         node_desc.prev = cpu_to_be32(new_node->prev);
 460         node_desc.type = new_node->type;
 461         node_desc.height = new_node->height;
 462         node_desc.num_recs = cpu_to_be16(new_node->num_recs);
 463         node_desc.reserved = 0;
 464         hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
 465
 466         rec = tree->node_size - 2;
 467         hfs_bnode_write_u16(new_node, rec, 14);
 468
 469         if (node) {
 470                 /* insert old root idx into new root */
 471                 node->parent = tree->root;
 472                 if (node->type == HFS_NODE_LEAF ||
 473                     tree->attributes & HFS_TREE_VARIDXKEYS)
 474                         key_size = hfs_bnode_read_u8(node, 14) + 1;
 475                 else
 476                         key_size = tree->max_key_len + 1;
 477                 hfs_bnode_copy(new_node, 14, node, 14, key_size);
 478
 479                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
 480                         key_size = tree->max_key_len + 1;
 481                         hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
 482                 }
 483                 key_size = (key_size + 1) & -2;
 484                 cnid = cpu_to_be32(node->this);
 485                 hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
 486
 487                 rec -= 2;
 488                 hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
 489
 490                 hfs_bnode_put(node);
 491         }
 492         hfs_bnode_put(new_node);
 493         mark_inode_dirty(tree->inode);
 494
 495         return 0;
 496 }