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