fs/hfs/bnode.c

   1 /*
   2  *  linux/fs/hfs/bnode.c
   3  *
   4  * Copyright (C) 2001
   5  * Brad Boyer (flar@allandria.com)
   6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
   7  *
   8  * Handle basic btree node operations
   9  */
  10
  11 #include <linux/pagemap.h>
  12 #include <linux/swap.h>
  13
  14 #include "btree.h"
  15
  16 #define REF_PAGES       0
  17
  18 void hfs_bnode_read(struct hfs_bnode *node, void *buf,
  19                 int off, int len)
  20 {
  21         struct page *page;
  22
  23         off += node->page_offset;
  24         page = node->page[0];
  25
  26         memcpy(buf, kmap(page) + off, len);
  27         kunmap(page);
  28 }
  29
  30 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
  31 {
  32         __be16 data;
  33         // optimize later...
  34         hfs_bnode_read(node, &data, off, 2);
  35         return be16_to_cpu(data);
  36 }
  37
  38 u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
  39 {
  40         u8 data;
  41         // optimize later...
  42         hfs_bnode_read(node, &data, off, 1);
  43         return data;
  44 }
  45
  46 void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
  47 {
  48         struct hfs_btree *tree;
  49         int key_len;
  50
  51         tree = node->tree;
  52         if (node->type == HFS_NODE_LEAF ||
  53             tree->attributes & HFS_TREE_VARIDXKEYS)
  54                 key_len = hfs_bnode_read_u8(node, off) + 1;
  55         else
  56                 key_len = tree->max_key_len + 1;
  57
  58         hfs_bnode_read(node, key, off, key_len);
  59 }
  60
  61 void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
  62 {
  63         struct page *page;
  64
  65         off += node->page_offset;
  66         page = node->page[0];
  67
  68         memcpy(kmap(page) + off, buf, len);
  69         kunmap(page);
  70         set_page_dirty(page);
  71 }
  72
  73 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
  74 {
  75         __be16 v = cpu_to_be16(data);
  76         // optimize later...
  77         hfs_bnode_write(node, &v, off, 2);
  78 }
  79
  80 void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
  81 {
  82         // optimize later...
  83         hfs_bnode_write(node, &data, off, 1);
  84 }
  85
  86 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
  87 {
  88         struct page *page;
  89
  90         off += node->page_offset;
  91         page = node->page[0];
  92
  93         memset(kmap(page) + off, 0, len);
  94         kunmap(page);
  95         set_page_dirty(page);
  96 }
  97
  98 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
  99                 struct hfs_bnode *src_node, int src, int len)
 100 {
 101         struct hfs_btree *tree;
 102         struct page *src_page, *dst_page;
 103
 104         dprint(DBG_BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
 105         if (!len)
 106                 return;
 107         tree = src_node->tree;
 108         src += src_node->page_offset;
 109         dst += dst_node->page_offset;
 110         src_page = src_node->page[0];
 111         dst_page = dst_node->page[0];
 112
 113         memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
 114         kunmap(src_page);
 115         kunmap(dst_page);
 116         set_page_dirty(dst_page);
 117 }
 118
 119 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
 120 {
 121         struct page *page;
 122         void *ptr;
 123
 124         dprint(DBG_BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
 125         if (!len)
 126                 return;
 127         src += node->page_offset;
 128         dst += node->page_offset;
 129         page = node->page[0];
 130         ptr = kmap(page);
 131         memmove(ptr + dst, ptr + src, len);
 132         kunmap(page);
 133         set_page_dirty(page);
 134 }
 135
 136 void hfs_bnode_dump(struct hfs_bnode *node)
 137 {
 138         struct hfs_bnode_desc desc;
 139         __be32 cnid;
 140         int i, off, key_off;
 141
 142         dprint(DBG_BNODE_MOD, "bnode: %d\n", node->this);
 143         hfs_bnode_read(node, &desc, 0, sizeof(desc));
 144         dprint(DBG_BNODE_MOD, "%d, %d, %d, %d, %d\n",
 145                 be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
 146                 desc.type, desc.height, be16_to_cpu(desc.num_recs));
 147
 148         off = node->tree->node_size - 2;
 149         for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
 150                 key_off = hfs_bnode_read_u16(node, off);
 151                 dprint(DBG_BNODE_MOD, " %d", key_off);
 152                 if (i && node->type == HFS_NODE_INDEX) {
 153                         int tmp;
 154
 155                         if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
 156                                 tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
 157                         else
 158                                 tmp = node->tree->max_key_len + 1;
 159                         dprint(DBG_BNODE_MOD, " (%d,%d", tmp, hfs_bnode_read_u8(node, key_off));
 160                         hfs_bnode_read(node, &cnid, key_off + tmp, 4);
 161                         dprint(DBG_BNODE_MOD, ",%d)", be32_to_cpu(cnid));
 162                 } else if (i && node->type == HFS_NODE_LEAF) {
 163                         int tmp;
 164
 165                         tmp = hfs_bnode_read_u8(node, key_off);
 166                         dprint(DBG_BNODE_MOD, " (%d)", tmp);
 167                 }
 168         }
 169         dprint(DBG_BNODE_MOD, "\n");
 170 }
 171
 172 void hfs_bnode_unlink(struct hfs_bnode *node)
 173 {
 174         struct hfs_btree *tree;
 175         struct hfs_bnode *tmp;
 176         __be32 cnid;
 177
 178         tree = node->tree;
 179         if (node->prev) {
 180                 tmp = hfs_bnode_find(tree, node->prev);
 181                 if (IS_ERR(tmp))
 182                         return;
 183                 tmp->next = node->next;
 184                 cnid = cpu_to_be32(tmp->next);
 185                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 186                 hfs_bnode_put(tmp);
 187         } else if (node->type == HFS_NODE_LEAF)
 188                 tree->leaf_head = node->next;
 189
 190         if (node->next) {
 191                 tmp = hfs_bnode_find(tree, node->next);
 192                 if (IS_ERR(tmp))
 193                         return;
 194                 tmp->prev = node->prev;
 195                 cnid = cpu_to_be32(tmp->prev);
 196                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
 197                 hfs_bnode_put(tmp);
 198         } else if (node->type == HFS_NODE_LEAF)
 199                 tree->leaf_tail = node->prev;
 200
 201         // move down?
 202         if (!node->prev && !node->next) {
 203                 printk("hfs_btree_del_level\n");
 204         }
 205         if (!node->parent) {
 206                 tree->root = 0;
 207                 tree->depth = 0;
 208         }
 209         set_bit(HFS_BNODE_DELETED, &node->flags);
 210 }
 211
 212 static inline int hfs_bnode_hash(u32 num)
 213 {
 214         num = (num >> 16) + num;
 215         num += num >> 8;
 216         return num & (NODE_HASH_SIZE - 1);
 217 }
 218
 219 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
 220 {
 221         struct hfs_bnode *node;
 222
 223         if (cnid >= tree->node_count) {
 224                 printk("HFS: request for non-existent node %d in B*Tree\n", cnid);
 225                 return NULL;
 226         }
 227
 228         for (node = tree->node_hash[hfs_bnode_hash(cnid)];
 229              node; node = node->next_hash) {
 230                 if (node->this == cnid) {
 231                         return node;
 232                 }
 233         }
 234         return NULL;
 235 }
 236
 237 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
 238 {
 239         struct super_block *sb;
 240         struct hfs_bnode *node, *node2;
 241         struct address_space *mapping;
 242         struct page *page;
 243         int size, block, i, hash;
 244         loff_t off;
 245
 246         if (cnid >= tree->node_count) {
 247                 printk("HFS: request for non-existent node %d in B*Tree\n", cnid);
 248                 return NULL;
 249         }
 250
 251         sb = tree->inode->i_sb;
 252         size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
 253                 sizeof(struct page *);
 254         node = kmalloc(size, GFP_KERNEL);
 255         if (!node)
 256                 return NULL;
 257         memset(node, 0, size);
 258         node->tree = tree;
 259         node->this = cnid;
 260         set_bit(HFS_BNODE_NEW, &node->flags);
 261         atomic_set(&node->refcnt, 1);
 262         dprint(DBG_BNODE_REFS, "new_node(%d:%d): 1\n",
 263                node->tree->cnid, node->this);
 264         init_waitqueue_head(&node->lock_wq);
 265         spin_lock(&tree->hash_lock);
 266         node2 = hfs_bnode_findhash(tree, cnid);
 267         if (!node2) {
 268                 hash = hfs_bnode_hash(cnid);
 269                 node->next_hash = tree->node_hash[hash];
 270                 tree->node_hash[hash] = node;
 271                 tree->node_hash_cnt++;
 272         } else {
 273                 spin_unlock(&tree->hash_lock);
 274                 kfree(node);
 275                 wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
 276                 return node2;
 277         }
 278         spin_unlock(&tree->hash_lock);
 279
 280         mapping = tree->inode->i_mapping;
 281         off = (loff_t)cnid * tree->node_size;
 282         block = off >> PAGE_CACHE_SHIFT;
 283         node->page_offset = off & ~PAGE_CACHE_MASK;
 284         for (i = 0; i < tree->pages_per_bnode; i++) {
 285                 page = read_cache_page(mapping, block++, (filler_t *)mapping->a_ops->readpage, NULL);
 286                 if (IS_ERR(page))
 287                         goto fail;
 288                 if (PageError(page)) {
 289                         page_cache_release(page);
 290                         goto fail;
 291                 }
 292 #if !REF_PAGES
 293                 page_cache_release(page);
 294 #endif
 295                 node->page[i] = page;
 296         }
 297
 298         return node;
 299 fail:
 300         set_bit(HFS_BNODE_ERROR, &node->flags);
 301         return node;
 302 }
 303
 304 void hfs_bnode_unhash(struct hfs_bnode *node)
 305 {
 306         struct hfs_bnode **p;
 307
 308         dprint(DBG_BNODE_REFS, "remove_node(%d:%d): %d\n",
 309                 node->tree->cnid, node->this, atomic_read(&node->refcnt));
 310         for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
 311              *p && *p != node; p = &(*p)->next_hash)
 312                 ;
 313         if (!*p)
 314                 BUG();
 315         *p = node->next_hash;
 316         node->tree->node_hash_cnt--;
 317 }
 318
 319 /* Load a particular node out of a tree */
 320 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
 321 {
 322         struct hfs_bnode *node;
 323         struct hfs_bnode_desc *desc;
 324         int i, rec_off, off, next_off;
 325         int entry_size, key_size;
 326
 327         spin_lock(&tree->hash_lock);
 328         node = hfs_bnode_findhash(tree, num);
 329         if (node) {
 330                 hfs_bnode_get(node);
 331                 spin_unlock(&tree->hash_lock);
 332                 wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
 333                 if (test_bit(HFS_BNODE_ERROR, &node->flags))
 334                         goto node_error;
 335                 return node;
 336         }
 337         spin_unlock(&tree->hash_lock);
 338         node = __hfs_bnode_create(tree, num);
 339         if (!node)
 340                 return ERR_PTR(-ENOMEM);
 341         if (test_bit(HFS_BNODE_ERROR, &node->flags))
 342                 goto node_error;
 343         if (!test_bit(HFS_BNODE_NEW, &node->flags))
 344                 return node;
 345
 346         desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
 347         node->prev = be32_to_cpu(desc->prev);
 348         node->next = be32_to_cpu(desc->next);
 349         node->num_recs = be16_to_cpu(desc->num_recs);
 350         node->type = desc->type;
 351         node->height = desc->height;
 352         kunmap(node->page[0]);
 353
 354         switch (node->type) {
 355         case HFS_NODE_HEADER:
 356         case HFS_NODE_MAP:
 357                 if (node->height != 0)
 358                         goto node_error;
 359                 break;
 360         case HFS_NODE_LEAF:
 361                 if (node->height != 1)
 362                         goto node_error;
 363                 break;
 364         case HFS_NODE_INDEX:
 365                 if (node->height <= 1 || node->height > tree->depth)
 366                         goto node_error;
 367                 break;
 368         default:
 369                 goto node_error;
 370         }
 371
 372         rec_off = tree->node_size - 2;
 373         off = hfs_bnode_read_u16(node, rec_off);
 374         if (off != sizeof(struct hfs_bnode_desc))
 375                 goto node_error;
 376         for (i = 1; i <= node->num_recs; off = next_off, i++) {
 377                 rec_off -= 2;
 378                 next_off = hfs_bnode_read_u16(node, rec_off);
 379                 if (next_off <= off ||
 380                     next_off > tree->node_size ||
 381                     next_off & 1)
 382                         goto node_error;
 383                 entry_size = next_off - off;
 384                 if (node->type != HFS_NODE_INDEX &&
 385                     node->type != HFS_NODE_LEAF)
 386                         continue;
 387                 key_size = hfs_bnode_read_u8(node, off) + 1;
 388                 if (key_size >= entry_size /*|| key_size & 1*/)
 389                         goto node_error;
 390         }
 391         clear_bit(HFS_BNODE_NEW, &node->flags);
 392         wake_up(&node->lock_wq);
 393         return node;
 394
 395 node_error:
 396         set_bit(HFS_BNODE_ERROR, &node->flags);
 397         clear_bit(HFS_BNODE_NEW, &node->flags);
 398         wake_up(&node->lock_wq);
 399         hfs_bnode_put(node);
 400         return ERR_PTR(-EIO);
 401 }
 402
 403 void hfs_bnode_free(struct hfs_bnode *node)
 404 {
 405         //int i;
 406
 407         //for (i = 0; i < node->tree->pages_per_bnode; i++)
 408         //      if (node->page[i])
 409         //              page_cache_release(node->page[i]);
 410         kfree(node);
 411 }
 412
 413 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
 414 {
 415         struct hfs_bnode *node;
 416         struct page **pagep;
 417         int i;
 418
 419         spin_lock(&tree->hash_lock);
 420         node = hfs_bnode_findhash(tree, num);
 421         spin_unlock(&tree->hash_lock);
 422         if (node)
 423                 BUG();
 424         node = __hfs_bnode_create(tree, num);
 425         if (!node)
 426                 return ERR_PTR(-ENOMEM);
 427         if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
 428                 hfs_bnode_put(node);
 429                 return ERR_PTR(-EIO);
 430         }
 431
 432         pagep = node->page;
 433         memset(kmap(*pagep) + node->page_offset, 0,
 434                min((int)PAGE_CACHE_SIZE, (int)tree->node_size));
 435         set_page_dirty(*pagep);
 436         kunmap(*pagep);
 437         for (i = 1; i < tree->pages_per_bnode; i++) {
 438                 memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE);
 439                 set_page_dirty(*pagep);
 440                 kunmap(*pagep);
 441         }
 442         clear_bit(HFS_BNODE_NEW, &node->flags);
 443         wake_up(&node->lock_wq);
 444
 445         return node;
 446 }
 447
 448 void hfs_bnode_get(struct hfs_bnode *node)
 449 {
 450         if (node) {
 451                 atomic_inc(&node->refcnt);
 452 #if REF_PAGES
 453                 {
 454                 int i;
 455                 for (i = 0; i < node->tree->pages_per_bnode; i++)
 456                         get_page(node->page[i]);
 457                 }
 458 #endif
 459                 dprint(DBG_BNODE_REFS, "get_node(%d:%d): %d\n",
 460                        node->tree->cnid, node->this, atomic_read(&node->refcnt));
 461         }
 462 }
 463
 464 /* Dispose of resources used by a node */
 465 void hfs_bnode_put(struct hfs_bnode *node)
 466 {
 467         if (node) {
 468                 struct hfs_btree *tree = node->tree;
 469                 int i;
 470
 471                 dprint(DBG_BNODE_REFS, "put_node(%d:%d): %d\n",
 472                        node->tree->cnid, node->this, atomic_read(&node->refcnt));
 473                 if (!atomic_read(&node->refcnt))
 474                         BUG();
 475                 if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock)) {
 476 #if REF_PAGES
 477                         for (i = 0; i < tree->pages_per_bnode; i++)
 478                                 put_page(node->page[i]);
 479 #endif
 480                         return;
 481                 }
 482                 for (i = 0; i < tree->pages_per_bnode; i++) {
 483                         mark_page_accessed(node->page[i]);
 484 #if REF_PAGES
 485                         put_page(node->page[i]);
 486 #endif
 487                 }
 488
 489                 if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
 490                         hfs_bnode_unhash(node);
 491                         spin_unlock(&tree->hash_lock);
 492                         hfs_bmap_free(node);
 493                         hfs_bnode_free(node);
 494                         return;
 495                 }
 496                 spin_unlock(&tree->hash_lock);
 497         }
 498 }