fs/hfsplus/bnode.c

   1 /*
   2  *  linux/fs/hfsplus/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/string.h>
  12 #include <linux/slab.h>
  13 #include <linux/pagemap.h>
  14 #include <linux/fs.h>
  15 #include <linux/swap.h>
  16
  17 #include "hfsplus_fs.h"
  18 #include "hfsplus_raw.h"
  19
  20 /* Copy a specified range of bytes from the raw data of a node */
  21 void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len)
  22 {
  23         struct page **pagep;
  24         int l;
  25
  26         off += node->page_offset;
  27         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
  28         off &= ~PAGE_CACHE_MASK;
  29
  30         l = min_t(int, len, PAGE_CACHE_SIZE - off);
  31         memcpy(buf, kmap(*pagep) + off, l);
  32         kunmap(*pagep);
  33
  34         while ((len -= l) != 0) {
  35                 buf += l;
  36                 l = min_t(int, len, PAGE_CACHE_SIZE);
  37                 memcpy(buf, kmap(*++pagep), l);
  38                 kunmap(*pagep);
  39         }
  40 }
  41
  42 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
  43 {
  44         __be16 data;
  45         /* TODO: optimize later... */
  46         hfs_bnode_read(node, &data, off, 2);
  47         return be16_to_cpu(data);
  48 }
  49
  50 u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
  51 {
  52         u8 data;
  53         /* TODO: optimize later... */
  54         hfs_bnode_read(node, &data, off, 1);
  55         return data;
  56 }
  57
  58 void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
  59 {
  60         struct hfs_btree *tree;
  61         int key_len;
  62
  63         tree = node->tree;
  64         if (node->type == HFS_NODE_LEAF ||
  65             tree->attributes & HFS_TREE_VARIDXKEYS ||
  66             node->tree->cnid == HFSPLUS_ATTR_CNID)
  67                 key_len = hfs_bnode_read_u16(node, off) + 2;
  68         else
  69                 key_len = tree->max_key_len + 2;
  70
  71         hfs_bnode_read(node, key, off, key_len);
  72 }
  73
  74 void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
  75 {
  76         struct page **pagep;
  77         int l;
  78
  79         off += node->page_offset;
  80         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
  81         off &= ~PAGE_CACHE_MASK;
  82
  83         l = min_t(int, len, PAGE_CACHE_SIZE - off);
  84         memcpy(kmap(*pagep) + off, buf, l);
  85         set_page_dirty(*pagep);
  86         kunmap(*pagep);
  87
  88         while ((len -= l) != 0) {
  89                 buf += l;
  90                 l = min_t(int, len, PAGE_CACHE_SIZE);
  91                 memcpy(kmap(*++pagep), buf, l);
  92                 set_page_dirty(*pagep);
  93                 kunmap(*pagep);
  94         }
  95 }
  96
  97 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
  98 {
  99         __be16 v = cpu_to_be16(data);
 100         /* TODO: optimize later... */
 101         hfs_bnode_write(node, &v, off, 2);
 102 }
 103
 104 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
 105 {
 106         struct page **pagep;
 107         int l;
 108
 109         off += node->page_offset;
 110         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 111         off &= ~PAGE_CACHE_MASK;
 112
 113         l = min_t(int, len, PAGE_CACHE_SIZE - off);
 114         memset(kmap(*pagep) + off, 0, l);
 115         set_page_dirty(*pagep);
 116         kunmap(*pagep);
 117
 118         while ((len -= l) != 0) {
 119                 l = min_t(int, len, PAGE_CACHE_SIZE);
 120                 memset(kmap(*++pagep), 0, l);
 121                 set_page_dirty(*pagep);
 122                 kunmap(*pagep);
 123         }
 124 }
 125
 126 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
 127                     struct hfs_bnode *src_node, int src, int len)
 128 {
 129         struct hfs_btree *tree;
 130         struct page **src_page, **dst_page;
 131         int l;
 132
 133         hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
 134         if (!len)
 135                 return;
 136         tree = src_node->tree;
 137         src += src_node->page_offset;
 138         dst += dst_node->page_offset;
 139         src_page = src_node->page + (src >> PAGE_CACHE_SHIFT);
 140         src &= ~PAGE_CACHE_MASK;
 141         dst_page = dst_node->page + (dst >> PAGE_CACHE_SHIFT);
 142         dst &= ~PAGE_CACHE_MASK;
 143
 144         if (src == dst) {
 145                 l = min_t(int, len, PAGE_CACHE_SIZE - src);
 146                 memcpy(kmap(*dst_page) + src, kmap(*src_page) + src, l);
 147                 kunmap(*src_page);
 148                 set_page_dirty(*dst_page);
 149                 kunmap(*dst_page);
 150
 151                 while ((len -= l) != 0) {
 152                         l = min_t(int, len, PAGE_CACHE_SIZE);
 153                         memcpy(kmap(*++dst_page), kmap(*++src_page), l);
 154                         kunmap(*src_page);
 155                         set_page_dirty(*dst_page);
 156                         kunmap(*dst_page);
 157                 }
 158         } else {
 159                 void *src_ptr, *dst_ptr;
 160
 161                 do {
 162                         src_ptr = kmap(*src_page) + src;
 163                         dst_ptr = kmap(*dst_page) + dst;
 164                         if (PAGE_CACHE_SIZE - src < PAGE_CACHE_SIZE - dst) {
 165                                 l = PAGE_CACHE_SIZE - src;
 166                                 src = 0;
 167                                 dst += l;
 168                         } else {
 169                                 l = PAGE_CACHE_SIZE - dst;
 170                                 src += l;
 171                                 dst = 0;
 172                         }
 173                         l = min(len, l);
 174                         memcpy(dst_ptr, src_ptr, l);
 175                         kunmap(*src_page);
 176                         set_page_dirty(*dst_page);
 177                         kunmap(*dst_page);
 178                         if (!dst)
 179                                 dst_page++;
 180                         else
 181                                 src_page++;
 182                 } while ((len -= l));
 183         }
 184 }
 185
 186 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
 187 {
 188         struct page **src_page, **dst_page;
 189         int l;
 190
 191         hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
 192         if (!len)
 193                 return;
 194         src += node->page_offset;
 195         dst += node->page_offset;
 196         if (dst > src) {
 197                 src += len - 1;
 198                 src_page = node->page + (src >> PAGE_CACHE_SHIFT);
 199                 src = (src & ~PAGE_CACHE_MASK) + 1;
 200                 dst += len - 1;
 201                 dst_page = node->page + (dst >> PAGE_CACHE_SHIFT);
 202                 dst = (dst & ~PAGE_CACHE_MASK) + 1;
 203
 204                 if (src == dst) {
 205                         while (src < len) {
 206                                 memmove(kmap(*dst_page), kmap(*src_page), src);
 207                                 kunmap(*src_page);
 208                                 set_page_dirty(*dst_page);
 209                                 kunmap(*dst_page);
 210                                 len -= src;
 211                                 src = PAGE_CACHE_SIZE;
 212                                 src_page--;
 213                                 dst_page--;
 214                         }
 215                         src -= len;
 216                         memmove(kmap(*dst_page) + src,
 217                                 kmap(*src_page) + src, len);
 218                         kunmap(*src_page);
 219                         set_page_dirty(*dst_page);
 220                         kunmap(*dst_page);
 221                 } else {
 222                         void *src_ptr, *dst_ptr;
 223
 224                         do {
 225                                 src_ptr = kmap(*src_page) + src;
 226                                 dst_ptr = kmap(*dst_page) + dst;
 227                                 if (src < dst) {
 228                                         l = src;
 229                                         src = PAGE_CACHE_SIZE;
 230                                         dst -= l;
 231                                 } else {
 232                                         l = dst;
 233                                         src -= l;
 234                                         dst = PAGE_CACHE_SIZE;
 235                                 }
 236                                 l = min(len, l);
 237                                 memmove(dst_ptr - l, src_ptr - l, l);
 238                                 kunmap(*src_page);
 239                                 set_page_dirty(*dst_page);
 240                                 kunmap(*dst_page);
 241                                 if (dst == PAGE_CACHE_SIZE)
 242                                         dst_page--;
 243                                 else
 244                                         src_page--;
 245                         } while ((len -= l));
 246                 }
 247         } else {
 248                 src_page = node->page + (src >> PAGE_CACHE_SHIFT);
 249                 src &= ~PAGE_CACHE_MASK;
 250                 dst_page = node->page + (dst >> PAGE_CACHE_SHIFT);
 251                 dst &= ~PAGE_CACHE_MASK;
 252
 253                 if (src == dst) {
 254                         l = min_t(int, len, PAGE_CACHE_SIZE - src);
 255                         memmove(kmap(*dst_page) + src,
 256                                 kmap(*src_page) + src, l);
 257                         kunmap(*src_page);
 258                         set_page_dirty(*dst_page);
 259                         kunmap(*dst_page);
 260
 261                         while ((len -= l) != 0) {
 262                                 l = min_t(int, len, PAGE_CACHE_SIZE);
 263                                 memmove(kmap(*++dst_page),
 264                                         kmap(*++src_page), l);
 265                                 kunmap(*src_page);
 266                                 set_page_dirty(*dst_page);
 267                                 kunmap(*dst_page);
 268                         }
 269                 } else {
 270                         void *src_ptr, *dst_ptr;
 271
 272                         do {
 273                                 src_ptr = kmap(*src_page) + src;
 274                                 dst_ptr = kmap(*dst_page) + dst;
 275                                 if (PAGE_CACHE_SIZE - src <
 276                                                 PAGE_CACHE_SIZE - dst) {
 277                                         l = PAGE_CACHE_SIZE - src;
 278                                         src = 0;
 279                                         dst += l;
 280                                 } else {
 281                                         l = PAGE_CACHE_SIZE - dst;
 282                                         src += l;
 283                                         dst = 0;
 284                                 }
 285                                 l = min(len, l);
 286                                 memmove(dst_ptr, src_ptr, l);
 287                                 kunmap(*src_page);
 288                                 set_page_dirty(*dst_page);
 289                                 kunmap(*dst_page);
 290                                 if (!dst)
 291                                         dst_page++;
 292                                 else
 293                                         src_page++;
 294                         } while ((len -= l));
 295                 }
 296         }
 297 }
 298
 299 void hfs_bnode_dump(struct hfs_bnode *node)
 300 {
 301         struct hfs_bnode_desc desc;
 302         __be32 cnid;
 303         int i, off, key_off;
 304
 305         hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
 306         hfs_bnode_read(node, &desc, 0, sizeof(desc));
 307         hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
 308                 be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
 309                 desc.type, desc.height, be16_to_cpu(desc.num_recs));
 310
 311         off = node->tree->node_size - 2;
 312         for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
 313                 key_off = hfs_bnode_read_u16(node, off);
 314                 hfs_dbg(BNODE_MOD, " %d", key_off);
 315                 if (i && node->type == HFS_NODE_INDEX) {
 316                         int tmp;
 317
 318                         if (node->tree->attributes & HFS_TREE_VARIDXKEYS ||
 319                                         node->tree->cnid == HFSPLUS_ATTR_CNID)
 320                                 tmp = hfs_bnode_read_u16(node, key_off) + 2;
 321                         else
 322                                 tmp = node->tree->max_key_len + 2;
 323                         hfs_dbg_cont(BNODE_MOD, " (%d", tmp);
 324                         hfs_bnode_read(node, &cnid, key_off + tmp, 4);
 325                         hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
 326                 } else if (i && node->type == HFS_NODE_LEAF) {
 327                         int tmp;
 328
 329                         tmp = hfs_bnode_read_u16(node, key_off);
 330                         hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
 331                 }
 332         }
 333         hfs_dbg_cont(BNODE_MOD, "\n");
 334 }
 335
 336 void hfs_bnode_unlink(struct hfs_bnode *node)
 337 {
 338         struct hfs_btree *tree;
 339         struct hfs_bnode *tmp;
 340         __be32 cnid;
 341
 342         tree = node->tree;
 343         if (node->prev) {
 344                 tmp = hfs_bnode_find(tree, node->prev);
 345                 if (IS_ERR(tmp))
 346                         return;
 347                 tmp->next = node->next;
 348                 cnid = cpu_to_be32(tmp->next);
 349                 hfs_bnode_write(tmp, &cnid,
 350                         offsetof(struct hfs_bnode_desc, next), 4);
 351                 hfs_bnode_put(tmp);
 352         } else if (node->type == HFS_NODE_LEAF)
 353                 tree->leaf_head = node->next;
 354
 355         if (node->next) {
 356                 tmp = hfs_bnode_find(tree, node->next);
 357                 if (IS_ERR(tmp))
 358                         return;
 359                 tmp->prev = node->prev;
 360                 cnid = cpu_to_be32(tmp->prev);
 361                 hfs_bnode_write(tmp, &cnid,
 362                         offsetof(struct hfs_bnode_desc, prev), 4);
 363                 hfs_bnode_put(tmp);
 364         } else if (node->type == HFS_NODE_LEAF)
 365                 tree->leaf_tail = node->prev;
 366
 367         /* move down? */
 368         if (!node->prev && !node->next)
 369                 hfs_dbg(BNODE_MOD, "hfs_btree_del_level\n");
 370         if (!node->parent) {
 371                 tree->root = 0;
 372                 tree->depth = 0;
 373         }
 374         set_bit(HFS_BNODE_DELETED, &node->flags);
 375 }
 376
 377 static inline int hfs_bnode_hash(u32 num)
 378 {
 379         num = (num >> 16) + num;
 380         num += num >> 8;
 381         return num & (NODE_HASH_SIZE - 1);
 382 }
 383
 384 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
 385 {
 386         struct hfs_bnode *node;
 387
 388         if (cnid >= tree->node_count) {
 389                 pr_err("request for non-existent node %d in B*Tree\n",
 390                        cnid);
 391                 return NULL;
 392         }
 393
 394         for (node = tree->node_hash[hfs_bnode_hash(cnid)];
 395                         node; node = node->next_hash)
 396                 if (node->this == cnid)
 397                         return node;
 398         return NULL;
 399 }
 400
 401 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
 402 {
 403         struct super_block *sb;
 404         struct hfs_bnode *node, *node2;
 405         struct address_space *mapping;
 406         struct page *page;
 407         int size, block, i, hash;
 408         loff_t off;
 409
 410         if (cnid >= tree->node_count) {
 411                 pr_err("request for non-existent node %d in B*Tree\n",
 412                        cnid);
 413                 return NULL;
 414         }
 415
 416         sb = tree->inode->i_sb;
 417         size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
 418                 sizeof(struct page *);
 419         node = kzalloc(size, GFP_KERNEL);
 420         if (!node)
 421                 return NULL;
 422         node->tree = tree;
 423         node->this = cnid;
 424         set_bit(HFS_BNODE_NEW, &node->flags);
 425         atomic_set(&node->refcnt, 1);
 426         hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
 427                 node->tree->cnid, node->this);
 428         init_waitqueue_head(&node->lock_wq);
 429         spin_lock(&tree->hash_lock);
 430         node2 = hfs_bnode_findhash(tree, cnid);
 431         if (!node2) {
 432                 hash = hfs_bnode_hash(cnid);
 433                 node->next_hash = tree->node_hash[hash];
 434                 tree->node_hash[hash] = node;
 435                 tree->node_hash_cnt++;
 436         } else {
 437                 spin_unlock(&tree->hash_lock);
 438                 kfree(node);
 439                 wait_event(node2->lock_wq,
 440                         !test_bit(HFS_BNODE_NEW, &node2->flags));
 441                 return node2;
 442         }
 443         spin_unlock(&tree->hash_lock);
 444
 445         mapping = tree->inode->i_mapping;
 446         off = (loff_t)cnid << tree->node_size_shift;
 447         block = off >> PAGE_CACHE_SHIFT;
 448         node->page_offset = off & ~PAGE_CACHE_MASK;
 449         for (i = 0; i < tree->pages_per_bnode; block++, i++) {
 450                 page = read_mapping_page(mapping, block, NULL);
 451                 if (IS_ERR(page))
 452                         goto fail;
 453                 if (PageError(page)) {
 454                         page_cache_release(page);
 455                         goto fail;
 456                 }
 457                 node->page[i] = page;
 458         }
 459
 460         return node;
 461 fail:
 462         set_bit(HFS_BNODE_ERROR, &node->flags);
 463         return node;
 464 }
 465
 466 void hfs_bnode_unhash(struct hfs_bnode *node)
 467 {
 468         struct hfs_bnode **p;
 469
 470         hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
 471                 node->tree->cnid, node->this, atomic_read(&node->refcnt));
 472         for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
 473              *p && *p != node; p = &(*p)->next_hash)
 474                 ;
 475         BUG_ON(!*p);
 476         *p = node->next_hash;
 477         node->tree->node_hash_cnt--;
 478 }
 479
 480 /* Load a particular node out of a tree */
 481 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
 482 {
 483         struct hfs_bnode *node;
 484         struct hfs_bnode_desc *desc;
 485         int i, rec_off, off, next_off;
 486         int entry_size, key_size;
 487
 488         spin_lock(&tree->hash_lock);
 489         node = hfs_bnode_findhash(tree, num);
 490         if (node) {
 491                 hfs_bnode_get(node);
 492                 spin_unlock(&tree->hash_lock);
 493                 wait_event(node->lock_wq,
 494                         !test_bit(HFS_BNODE_NEW, &node->flags));
 495                 if (test_bit(HFS_BNODE_ERROR, &node->flags))
 496                         goto node_error;
 497                 return node;
 498         }
 499         spin_unlock(&tree->hash_lock);
 500         node = __hfs_bnode_create(tree, num);
 501         if (!node)
 502                 return ERR_PTR(-ENOMEM);
 503         if (test_bit(HFS_BNODE_ERROR, &node->flags))
 504                 goto node_error;
 505         if (!test_bit(HFS_BNODE_NEW, &node->flags))
 506                 return node;
 507
 508         desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) +
 509                         node->page_offset);
 510         node->prev = be32_to_cpu(desc->prev);
 511         node->next = be32_to_cpu(desc->next);
 512         node->num_recs = be16_to_cpu(desc->num_recs);
 513         node->type = desc->type;
 514         node->height = desc->height;
 515         kunmap(node->page[0]);
 516
 517         switch (node->type) {
 518         case HFS_NODE_HEADER:
 519         case HFS_NODE_MAP:
 520                 if (node->height != 0)
 521                         goto node_error;
 522                 break;
 523         case HFS_NODE_LEAF:
 524                 if (node->height != 1)
 525                         goto node_error;
 526                 break;
 527         case HFS_NODE_INDEX:
 528                 if (node->height <= 1 || node->height > tree->depth)
 529                         goto node_error;
 530                 break;
 531         default:
 532                 goto node_error;
 533         }
 534
 535         rec_off = tree->node_size - 2;
 536         off = hfs_bnode_read_u16(node, rec_off);
 537         if (off != sizeof(struct hfs_bnode_desc))
 538                 goto node_error;
 539         for (i = 1; i <= node->num_recs; off = next_off, i++) {
 540                 rec_off -= 2;
 541                 next_off = hfs_bnode_read_u16(node, rec_off);
 542                 if (next_off <= off ||
 543                     next_off > tree->node_size ||
 544                     next_off & 1)
 545                         goto node_error;
 546                 entry_size = next_off - off;
 547                 if (node->type != HFS_NODE_INDEX &&
 548                     node->type != HFS_NODE_LEAF)
 549                         continue;
 550                 key_size = hfs_bnode_read_u16(node, off) + 2;
 551                 if (key_size >= entry_size || key_size & 1)
 552                         goto node_error;
 553         }
 554         clear_bit(HFS_BNODE_NEW, &node->flags);
 555         wake_up(&node->lock_wq);
 556         return node;
 557
 558 node_error:
 559         set_bit(HFS_BNODE_ERROR, &node->flags);
 560         clear_bit(HFS_BNODE_NEW, &node->flags);
 561         wake_up(&node->lock_wq);
 562         hfs_bnode_put(node);
 563         return ERR_PTR(-EIO);
 564 }
 565
 566 void hfs_bnode_free(struct hfs_bnode *node)
 567 {
 568         int i;
 569
 570         for (i = 0; i < node->tree->pages_per_bnode; i++)
 571                 if (node->page[i])
 572                         page_cache_release(node->page[i]);
 573         kfree(node);
 574 }
 575
 576 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
 577 {
 578         struct hfs_bnode *node;
 579         struct page **pagep;
 580         int i;
 581
 582         spin_lock(&tree->hash_lock);
 583         node = hfs_bnode_findhash(tree, num);
 584         spin_unlock(&tree->hash_lock);
 585         if (node) {
 586                 pr_crit("new node %u already hashed?\n", num);
 587                 WARN_ON(1);
 588                 return node;
 589         }
 590         node = __hfs_bnode_create(tree, num);
 591         if (!node)
 592                 return ERR_PTR(-ENOMEM);
 593         if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
 594                 hfs_bnode_put(node);
 595                 return ERR_PTR(-EIO);
 596         }
 597
 598         pagep = node->page;
 599         memset(kmap(*pagep) + node->page_offset, 0,
 600                min_t(int, PAGE_CACHE_SIZE, tree->node_size));
 601         set_page_dirty(*pagep);
 602         kunmap(*pagep);
 603         for (i = 1; i < tree->pages_per_bnode; i++) {
 604                 memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE);
 605                 set_page_dirty(*pagep);
 606                 kunmap(*pagep);
 607         }
 608         clear_bit(HFS_BNODE_NEW, &node->flags);
 609         wake_up(&node->lock_wq);
 610
 611         return node;
 612 }
 613
 614 void hfs_bnode_get(struct hfs_bnode *node)
 615 {
 616         if (node) {
 617                 atomic_inc(&node->refcnt);
 618                 hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
 619                         node->tree->cnid, node->this,
 620                         atomic_read(&node->refcnt));
 621         }
 622 }
 623
 624 /* Dispose of resources used by a node */
 625 void hfs_bnode_put(struct hfs_bnode *node)
 626 {
 627         if (node) {
 628                 struct hfs_btree *tree = node->tree;
 629                 int i;
 630
 631                 hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
 632                         node->tree->cnid, node->this,
 633                         atomic_read(&node->refcnt));
 634                 BUG_ON(!atomic_read(&node->refcnt));
 635                 if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
 636                         return;
 637                 for (i = 0; i < tree->pages_per_bnode; i++) {
 638                         if (!node->page[i])
 639                                 continue;
 640                         mark_page_accessed(node->page[i]);
 641                 }
 642
 643                 if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
 644                         hfs_bnode_unhash(node);
 645                         spin_unlock(&tree->hash_lock);
 646                         if (hfs_bnode_need_zeroout(tree))
 647                                 hfs_bnode_clear(node, 0, tree->node_size);
 648                         hfs_bmap_free(node);
 649                         hfs_bnode_free(node);
 650                         return;
 651                 }
 652                 spin_unlock(&tree->hash_lock);
 653         }
 654 }
 655
 656 /*
 657  * Unused nodes have to be zeroed if this is the catalog tree and
 658  * a corresponding flag in the volume header is set.
 659  */
 660 bool hfs_bnode_need_zeroout(struct hfs_btree *tree)
 661 {
 662         struct super_block *sb = tree->inode->i_sb;
 663         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 664         const u32 volume_attr = be32_to_cpu(sbi->s_vhdr->attributes);
 665
 666         return tree->cnid == HFSPLUS_CAT_CNID &&
 667                 volume_attr & HFSPLUS_VOL_UNUSED_NODE_FIX;
 668 }