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/slab.h>
  13 #include <linux/swap.h>
  14
  15 #include "btree.h"
  16
  17 void hfs_bnode_read(struct hfs_bnode *node, void *buf,
  18                 int off, int len)
  19 {
  20         struct page *page;
  21
  22         off += node->page_offset;
  23         page = node->page[0];
  24
  25         memcpy(buf, kmap(page) + off, len);
  26         kunmap(page);
  27 }
  28
  29 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
  30 {
  31         __be16 data;
  32         // optimize later...
  33         hfs_bnode_read(node, &data, off, 2);
  34         return be16_to_cpu(data);
  35 }
  36
  37 u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
  38 {
  39         u8 data;
  40         // optimize later...
  41         hfs_bnode_read(node, &data, off, 1);
  42         return data;
  43 }
  44
  45 void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
  46 {
  47         struct hfs_btree *tree;
  48         int key_len;
  49
  50         tree = node->tree;
  51         if (node->type == HFS_NODE_LEAF ||
  52             tree->attributes & HFS_TREE_VARIDXKEYS)
  53                 key_len = hfs_bnode_read_u8(node, off) + 1;
  54         else
  55                 key_len = tree->max_key_len + 1;
  56
  57         hfs_bnode_read(node, key, off, key_len);
  58 }
  59
  60 void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
  61 {
  62         struct page *page;
  63
  64         off += node->page_offset;
  65         page = node->page[0];
  66
  67         memcpy(kmap(page) + off, buf, len);
  68         kunmap(page);
  69         set_page_dirty(page);
  70 }
  71
  72 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
  73 {
  74         __be16 v = cpu_to_be16(data);
  75         // optimize later...
  76         hfs_bnode_write(node, &v, off, 2);
  77 }
  78
  79 void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
  80 {
  81         // optimize later...
  82         hfs_bnode_write(node, &data, off, 1);
  83 }
  84
  85 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
  86 {
  87         struct page *page;
  88
  89         off += node->page_offset;
  90         page = node->page[0];
  91
  92         memset(kmap(page) + off, 0, len);
  93         kunmap(page);
  94         set_page_dirty(page);
  95 }
  96
  97 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
  98                 struct hfs_bnode *src_node, int src, int len)
  99 {
 100         struct hfs_btree *tree;
 101         struct page *src_page, *dst_page;
 102
 103         hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
 104         if (!len)
 105                 return;
 106         tree = src_node->tree;
 107         src += src_node->page_offset;
 108         dst += dst_node->page_offset;
 109         src_page = src_node->page[0];
 110         dst_page = dst_node->page[0];
 111
 112         memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
 113         kunmap(src_page);
 114         kunmap(dst_page);
 115         set_page_dirty(dst_page);
 116 }
 117
 118 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
 119 {
 120         struct page *page;
 121         void *ptr;
 122
 123         hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
 124         if (!len)
 125                 return;
 126         src += node->page_offset;
 127         dst += node->page_offset;
 128         page = node->page[0];
 129         ptr = kmap(page);
 130         memmove(ptr + dst, ptr + src, len);
 131         kunmap(page);
 132         set_page_dirty(page);
 133 }
 134
 135 void hfs_bnode_dump(struct hfs_bnode *node)
 136 {
 137         struct hfs_bnode_desc desc;
 138         __be32 cnid;
 139         int i, off, key_off;
 140
 141         hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
 142         hfs_bnode_read(node, &desc, 0, sizeof(desc));
 143         hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
 144                 be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
 145                 desc.type, desc.height, be16_to_cpu(desc.num_recs));
 146
 147         off = node->tree->node_size - 2;
 148         for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
 149                 key_off = hfs_bnode_read_u16(node, off);
 150                 hfs_dbg_cont(BNODE_MOD, " %d", key_off);
 151                 if (i && node->type == HFS_NODE_INDEX) {
 152                         int tmp;
 153
 154                         if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
 155                                 tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
 156                         else
 157                                 tmp = node->tree->max_key_len + 1;
 158                         hfs_dbg_cont(BNODE_MOD, " (%d,%d",
 159                                      tmp, hfs_bnode_read_u8(node, key_off));
 160                         hfs_bnode_read(node, &cnid, key_off + tmp, 4);
 161                         hfs_dbg_cont(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                         hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
 167                 }
 168         }
 169         hfs_dbg_cont(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(KERN_DEBUG "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                 pr_err("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                 pr_err("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 = kzalloc(size, GFP_KERNEL);
 255         if (!node)
 256                 return NULL;
 257         node->tree = tree;
 258         node->this = cnid;
 259         set_bit(HFS_BNODE_NEW, &node->flags);
 260         atomic_set(&node->refcnt, 1);
 261         hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
 262                 node->tree->cnid, node->this);
 263         init_waitqueue_head(&node->lock_wq);
 264         spin_lock(&tree->hash_lock);
 265         node2 = hfs_bnode_findhash(tree, cnid);
 266         if (!node2) {
 267                 hash = hfs_bnode_hash(cnid);
 268                 node->next_hash = tree->node_hash[hash];
 269                 tree->node_hash[hash] = node;
 270                 tree->node_hash_cnt++;
 271         } else {
 272                 spin_unlock(&tree->hash_lock);
 273                 kfree(node);
 274                 wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
 275                 return node2;
 276         }
 277         spin_unlock(&tree->hash_lock);
 278
 279         mapping = tree->inode->i_mapping;
 280         off = (loff_t)cnid * tree->node_size;
 281         block = off >> PAGE_SHIFT;
 282         node->page_offset = off & ~PAGE_MASK;
 283         for (i = 0; i < tree->pages_per_bnode; i++) {
 284                 page = read_mapping_page(mapping, block++, NULL);
 285                 if (IS_ERR(page))
 286                         goto fail;
 287                 if (PageError(page)) {
 288                         put_page(page);
 289                         goto fail;
 290                 }
 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         hfs_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         BUG_ON(!*p);
 310         *p = node->next_hash;
 311         node->tree->node_hash_cnt--;
 312 }
 313
 314 /* Load a particular node out of a tree */
 315 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
 316 {
 317         struct hfs_bnode *node;
 318         struct hfs_bnode_desc *desc;
 319         int i, rec_off, off, next_off;
 320         int entry_size, key_size;
 321
 322         spin_lock(&tree->hash_lock);
 323         node = hfs_bnode_findhash(tree, num);
 324         if (node) {
 325                 hfs_bnode_get(node);
 326                 spin_unlock(&tree->hash_lock);
 327                 wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
 328                 if (test_bit(HFS_BNODE_ERROR, &node->flags))
 329                         goto node_error;
 330                 return node;
 331         }
 332         spin_unlock(&tree->hash_lock);
 333         node = __hfs_bnode_create(tree, num);
 334         if (!node)
 335                 return ERR_PTR(-ENOMEM);
 336         if (test_bit(HFS_BNODE_ERROR, &node->flags))
 337                 goto node_error;
 338         if (!test_bit(HFS_BNODE_NEW, &node->flags))
 339                 return node;
 340
 341         desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
 342         node->prev = be32_to_cpu(desc->prev);
 343         node->next = be32_to_cpu(desc->next);
 344         node->num_recs = be16_to_cpu(desc->num_recs);
 345         node->type = desc->type;
 346         node->height = desc->height;
 347         kunmap(node->page[0]);
 348
 349         switch (node->type) {
 350         case HFS_NODE_HEADER:
 351         case HFS_NODE_MAP:
 352                 if (node->height != 0)
 353                         goto node_error;
 354                 break;
 355         case HFS_NODE_LEAF:
 356                 if (node->height != 1)
 357                         goto node_error;
 358                 break;
 359         case HFS_NODE_INDEX:
 360                 if (node->height <= 1 || node->height > tree->depth)
 361                         goto node_error;
 362                 break;
 363         default:
 364                 goto node_error;
 365         }
 366
 367         rec_off = tree->node_size - 2;
 368         off = hfs_bnode_read_u16(node, rec_off);
 369         if (off != sizeof(struct hfs_bnode_desc))
 370                 goto node_error;
 371         for (i = 1; i <= node->num_recs; off = next_off, i++) {
 372                 rec_off -= 2;
 373                 next_off = hfs_bnode_read_u16(node, rec_off);
 374                 if (next_off <= off ||
 375                     next_off > tree->node_size ||
 376                     next_off & 1)
 377                         goto node_error;
 378                 entry_size = next_off - off;
 379                 if (node->type != HFS_NODE_INDEX &&
 380                     node->type != HFS_NODE_LEAF)
 381                         continue;
 382                 key_size = hfs_bnode_read_u8(node, off) + 1;
 383                 if (key_size >= entry_size /*|| key_size & 1*/)
 384                         goto node_error;
 385         }
 386         clear_bit(HFS_BNODE_NEW, &node->flags);
 387         wake_up(&node->lock_wq);
 388         return node;
 389
 390 node_error:
 391         set_bit(HFS_BNODE_ERROR, &node->flags);
 392         clear_bit(HFS_BNODE_NEW, &node->flags);
 393         wake_up(&node->lock_wq);
 394         hfs_bnode_put(node);
 395         return ERR_PTR(-EIO);
 396 }
 397
 398 void hfs_bnode_free(struct hfs_bnode *node)
 399 {
 400         int i;
 401
 402         for (i = 0; i < node->tree->pages_per_bnode; i++)
 403                 if (node->page[i])
 404                         put_page(node->page[i]);
 405         kfree(node);
 406 }
 407
 408 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
 409 {
 410         struct hfs_bnode *node;
 411         struct page **pagep;
 412         int i;
 413
 414         spin_lock(&tree->hash_lock);
 415         node = hfs_bnode_findhash(tree, num);
 416         spin_unlock(&tree->hash_lock);
 417         if (node) {
 418                 pr_crit("new node %u already hashed?\n", num);
 419                 WARN_ON(1);
 420                 return node;
 421         }
 422         node = __hfs_bnode_create(tree, num);
 423         if (!node)
 424                 return ERR_PTR(-ENOMEM);
 425         if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
 426                 hfs_bnode_put(node);
 427                 return ERR_PTR(-EIO);
 428         }
 429
 430         pagep = node->page;
 431         memset(kmap(*pagep) + node->page_offset, 0,
 432                min((int)PAGE_SIZE, (int)tree->node_size));
 433         set_page_dirty(*pagep);
 434         kunmap(*pagep);
 435         for (i = 1; i < tree->pages_per_bnode; i++) {
 436                 memset(kmap(*++pagep), 0, PAGE_SIZE);
 437                 set_page_dirty(*pagep);
 438                 kunmap(*pagep);
 439         }
 440         clear_bit(HFS_BNODE_NEW, &node->flags);
 441         wake_up(&node->lock_wq);
 442
 443         return node;
 444 }
 445
 446 void hfs_bnode_get(struct hfs_bnode *node)
 447 {
 448         if (node) {
 449                 atomic_inc(&node->refcnt);
 450                 hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
 451                         node->tree->cnid, node->this,
 452                         atomic_read(&node->refcnt));
 453         }
 454 }
 455
 456 /* Dispose of resources used by a node */
 457 void hfs_bnode_put(struct hfs_bnode *node)
 458 {
 459         if (node) {
 460                 struct hfs_btree *tree = node->tree;
 461                 int i;
 462
 463                 hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
 464                         node->tree->cnid, node->this,
 465                         atomic_read(&node->refcnt));
 466                 BUG_ON(!atomic_read(&node->refcnt));
 467                 if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
 468                         return;
 469                 for (i = 0; i < tree->pages_per_bnode; i++) {
 470                         if (!node->page[i])
 471                                 continue;
 472                         mark_page_accessed(node->page[i]);
 473                 }
 474
 475                 if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
 476                         hfs_bnode_unhash(node);
 477                         spin_unlock(&tree->hash_lock);
 478                         hfs_bmap_free(node);
 479                         hfs_bnode_free(node);
 480                         return;
 481                 }
 482                 spin_unlock(&tree->hash_lock);
 483         }
 484 }