fs/hfsplus/btree.c

   1 /*
   2  *  linux/fs/hfsplus/btree.c
   3  *
   4  * Copyright (C) 2001
   5  * Brad Boyer (flar@allandria.com)
   6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
   7  *
   8  * Handle opening/closing btree
   9  */
  10
  11 #include <linux/slab.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/log2.h>
  14
  15 #include "hfsplus_fs.h"
  16 #include "hfsplus_raw.h"
  17
  18
  19 /* Get a reference to a B*Tree and do some initial checks */
  20 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id)
  21 {
  22         struct hfs_btree *tree;
  23         struct hfs_btree_header_rec *head;
  24         struct address_space *mapping;
  25         struct inode *inode;
  26         struct page *page;
  27         unsigned int size;
  28
  29         tree = kzalloc(sizeof(*tree), GFP_KERNEL);
  30         if (!tree)
  31                 return NULL;
  32
  33         mutex_init(&tree->tree_lock);
  34         spin_lock_init(&tree->hash_lock);
  35         tree->sb = sb;
  36         tree->cnid = id;
  37         inode = hfsplus_iget(sb, id);
  38         if (IS_ERR(inode))
  39                 goto free_tree;
  40         tree->inode = inode;
  41
  42         if (!HFSPLUS_I(tree->inode)->first_blocks) {
  43                 printk(KERN_ERR
  44                        "hfs: invalid btree extent records (0 size).\n");
  45                 goto free_inode;
  46         }
  47
  48         mapping = tree->inode->i_mapping;
  49         page = read_mapping_page(mapping, 0, NULL);
  50         if (IS_ERR(page))
  51                 goto free_inode;
  52
  53         /* Load the header */
  54         head = (struct hfs_btree_header_rec *)(kmap(page) +
  55                 sizeof(struct hfs_bnode_desc));
  56         tree->root = be32_to_cpu(head->root);
  57         tree->leaf_count = be32_to_cpu(head->leaf_count);
  58         tree->leaf_head = be32_to_cpu(head->leaf_head);
  59         tree->leaf_tail = be32_to_cpu(head->leaf_tail);
  60         tree->node_count = be32_to_cpu(head->node_count);
  61         tree->free_nodes = be32_to_cpu(head->free_nodes);
  62         tree->attributes = be32_to_cpu(head->attributes);
  63         tree->node_size = be16_to_cpu(head->node_size);
  64         tree->max_key_len = be16_to_cpu(head->max_key_len);
  65         tree->depth = be16_to_cpu(head->depth);
  66
  67         /* Verify the tree and set the correct compare function */
  68         switch (id) {
  69         case HFSPLUS_EXT_CNID:
  70                 if (tree->max_key_len != HFSPLUS_EXT_KEYLEN - sizeof(u16)) {
  71                         printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
  72                                 tree->max_key_len);
  73                         goto fail_page;
  74                 }
  75                 if (tree->attributes & HFS_TREE_VARIDXKEYS) {
  76                         printk(KERN_ERR "hfs: invalid extent btree flag\n");
  77                         goto fail_page;
  78                 }
  79
  80                 tree->keycmp = hfsplus_ext_cmp_key;
  81                 break;
  82         case HFSPLUS_CAT_CNID:
  83                 if (tree->max_key_len != HFSPLUS_CAT_KEYLEN - sizeof(u16)) {
  84                         printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
  85                                 tree->max_key_len);
  86                         goto fail_page;
  87                 }
  88                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
  89                         printk(KERN_ERR "hfs: invalid catalog btree flag\n");
  90                         goto fail_page;
  91                 }
  92
  93                 if (test_bit(HFSPLUS_SB_HFSX, &HFSPLUS_SB(sb)->flags) &&
  94                     (head->key_type == HFSPLUS_KEY_BINARY))
  95                         tree->keycmp = hfsplus_cat_bin_cmp_key;
  96                 else {
  97                         tree->keycmp = hfsplus_cat_case_cmp_key;
  98                         set_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
  99                 }
 100                 break;
 101         default:
 102                 printk(KERN_ERR "hfs: unknown B*Tree requested\n");
 103                 goto fail_page;
 104         }
 105
 106         if (!(tree->attributes & HFS_TREE_BIGKEYS)) {
 107                 printk(KERN_ERR "hfs: invalid btree flag\n");
 108                 goto fail_page;
 109         }
 110
 111         size = tree->node_size;
 112         if (!is_power_of_2(size))
 113                 goto fail_page;
 114         if (!tree->node_count)
 115                 goto fail_page;
 116
 117         tree->node_size_shift = ffs(size) - 1;
 118
 119         tree->pages_per_bnode =
 120                 (tree->node_size + PAGE_CACHE_SIZE - 1) >>
 121                 PAGE_CACHE_SHIFT;
 122
 123         kunmap(page);
 124         page_cache_release(page);
 125         return tree;
 126
 127  fail_page:
 128         page_cache_release(page);
 129  free_inode:
 130         tree->inode->i_mapping->a_ops = &hfsplus_aops;
 131         iput(tree->inode);
 132  free_tree:
 133         kfree(tree);
 134         return NULL;
 135 }
 136
 137 /* Release resources used by a btree */
 138 void hfs_btree_close(struct hfs_btree *tree)
 139 {
 140         struct hfs_bnode *node;
 141         int i;
 142
 143         if (!tree)
 144                 return;
 145
 146         for (i = 0; i < NODE_HASH_SIZE; i++) {
 147                 while ((node = tree->node_hash[i])) {
 148                         tree->node_hash[i] = node->next_hash;
 149                         if (atomic_read(&node->refcnt))
 150                                 printk(KERN_CRIT "hfs: node %d:%d "
 151                                                 "still has %d user(s)!\n",
 152                                         node->tree->cnid, node->this,
 153                                         atomic_read(&node->refcnt));
 154                         hfs_bnode_free(node);
 155                         tree->node_hash_cnt--;
 156                 }
 157         }
 158         iput(tree->inode);
 159         kfree(tree);
 160 }
 161
 162 void hfs_btree_write(struct hfs_btree *tree)
 163 {
 164         struct hfs_btree_header_rec *head;
 165         struct hfs_bnode *node;
 166         struct page *page;
 167
 168         node = hfs_bnode_find(tree, 0);
 169         if (IS_ERR(node))
 170                 /* panic? */
 171                 return;
 172         /* Load the header */
 173         page = node->page[0];
 174         head = (struct hfs_btree_header_rec *)(kmap(page) +
 175                 sizeof(struct hfs_bnode_desc));
 176
 177         head->root = cpu_to_be32(tree->root);
 178         head->leaf_count = cpu_to_be32(tree->leaf_count);
 179         head->leaf_head = cpu_to_be32(tree->leaf_head);
 180         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
 181         head->node_count = cpu_to_be32(tree->node_count);
 182         head->free_nodes = cpu_to_be32(tree->free_nodes);
 183         head->attributes = cpu_to_be32(tree->attributes);
 184         head->depth = cpu_to_be16(tree->depth);
 185
 186         kunmap(page);
 187         set_page_dirty(page);
 188         hfs_bnode_put(node);
 189 }
 190
 191 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 192 {
 193         struct hfs_btree *tree = prev->tree;
 194         struct hfs_bnode *node;
 195         struct hfs_bnode_desc desc;
 196         __be32 cnid;
 197
 198         node = hfs_bnode_create(tree, idx);
 199         if (IS_ERR(node))
 200                 return node;
 201
 202         tree->free_nodes--;
 203         prev->next = idx;
 204         cnid = cpu_to_be32(idx);
 205         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 206
 207         node->type = HFS_NODE_MAP;
 208         node->num_recs = 1;
 209         hfs_bnode_clear(node, 0, tree->node_size);
 210         desc.next = 0;
 211         desc.prev = 0;
 212         desc.type = HFS_NODE_MAP;
 213         desc.height = 0;
 214         desc.num_recs = cpu_to_be16(1);
 215         desc.reserved = 0;
 216         hfs_bnode_write(node, &desc, 0, sizeof(desc));
 217         hfs_bnode_write_u16(node, 14, 0x8000);
 218         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
 219         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
 220
 221         return node;
 222 }
 223
 224 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 225 {
 226         struct hfs_bnode *node, *next_node;
 227         struct page **pagep;
 228         u32 nidx, idx;
 229         unsigned off;
 230         u16 off16;
 231         u16 len;
 232         u8 *data, byte, m;
 233         int i;
 234
 235         while (!tree->free_nodes) {
 236                 struct inode *inode = tree->inode;
 237                 struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 238                 u32 count;
 239                 int res;
 240
 241                 res = hfsplus_file_extend(inode);
 242                 if (res)
 243                         return ERR_PTR(res);
 244                 hip->phys_size = inode->i_size =
 245                         (loff_t)hip->alloc_blocks <<
 246                                 HFSPLUS_SB(tree->sb)->alloc_blksz_shift;
 247                 hip->fs_blocks =
 248                         hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift;
 249                 inode_set_bytes(inode, inode->i_size);
 250                 count = inode->i_size >> tree->node_size_shift;
 251                 tree->free_nodes = count - tree->node_count;
 252                 tree->node_count = count;
 253         }
 254
 255         nidx = 0;
 256         node = hfs_bnode_find(tree, nidx);
 257         if (IS_ERR(node))
 258                 return node;
 259         len = hfs_brec_lenoff(node, 2, &off16);
 260         off = off16;
 261
 262         off += node->page_offset;
 263         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 264         data = kmap(*pagep);
 265         off &= ~PAGE_CACHE_MASK;
 266         idx = 0;
 267
 268         for (;;) {
 269                 while (len) {
 270                         byte = data[off];
 271                         if (byte != 0xff) {
 272                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
 273                                         if (!(byte & m)) {
 274                                                 idx += i;
 275                                                 data[off] |= m;
 276                                                 set_page_dirty(*pagep);
 277                                                 kunmap(*pagep);
 278                                                 tree->free_nodes--;
 279                                                 mark_inode_dirty(tree->inode);
 280                                                 hfs_bnode_put(node);
 281                                                 return hfs_bnode_create(tree,
 282                                                         idx);
 283                                         }
 284                                 }
 285                         }
 286                         if (++off >= PAGE_CACHE_SIZE) {
 287                                 kunmap(*pagep);
 288                                 data = kmap(*++pagep);
 289                                 off = 0;
 290                         }
 291                         idx += 8;
 292                         len--;
 293                 }
 294                 kunmap(*pagep);
 295                 nidx = node->next;
 296                 if (!nidx) {
 297                         dprint(DBG_BNODE_MOD, "hfs: create new bmap node.\n");
 298                         next_node = hfs_bmap_new_bmap(node, idx);
 299                 } else
 300                         next_node = hfs_bnode_find(tree, nidx);
 301                 hfs_bnode_put(node);
 302                 if (IS_ERR(next_node))
 303                         return next_node;
 304                 node = next_node;
 305
 306                 len = hfs_brec_lenoff(node, 0, &off16);
 307                 off = off16;
 308                 off += node->page_offset;
 309                 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 310                 data = kmap(*pagep);
 311                 off &= ~PAGE_CACHE_MASK;
 312         }
 313 }
 314
 315 void hfs_bmap_free(struct hfs_bnode *node)
 316 {
 317         struct hfs_btree *tree;
 318         struct page *page;
 319         u16 off, len;
 320         u32 nidx;
 321         u8 *data, byte, m;
 322
 323         dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
 324         BUG_ON(!node->this);
 325         tree = node->tree;
 326         nidx = node->this;
 327         node = hfs_bnode_find(tree, 0);
 328         if (IS_ERR(node))
 329                 return;
 330         len = hfs_brec_lenoff(node, 2, &off);
 331         while (nidx >= len * 8) {
 332                 u32 i;
 333
 334                 nidx -= len * 8;
 335                 i = node->next;
 336                 hfs_bnode_put(node);
 337                 if (!i) {
 338                         /* panic */;
 339                         printk(KERN_CRIT "hfs: unable to free bnode %u. "
 340                                         "bmap not found!\n",
 341                                 node->this);
 342                         return;
 343                 }
 344                 node = hfs_bnode_find(tree, i);
 345                 if (IS_ERR(node))
 346                         return;
 347                 if (node->type != HFS_NODE_MAP) {
 348                         /* panic */;
 349                         printk(KERN_CRIT "hfs: invalid bmap found! "
 350                                         "(%u,%d)\n",
 351                                 node->this, node->type);
 352                         hfs_bnode_put(node);
 353                         return;
 354                 }
 355                 len = hfs_brec_lenoff(node, 0, &off);
 356         }
 357         off += node->page_offset + nidx / 8;
 358         page = node->page[off >> PAGE_CACHE_SHIFT];
 359         data = kmap(page);
 360         off &= ~PAGE_CACHE_MASK;
 361         m = 1 << (~nidx & 7);
 362         byte = data[off];
 363         if (!(byte & m)) {
 364                 printk(KERN_CRIT "hfs: trying to free free bnode "
 365                                 "%u(%d)\n",
 366                         node->this, node->type);
 367                 kunmap(page);
 368                 hfs_bnode_put(node);
 369                 return;
 370         }
 371         data[off] = byte & ~m;
 372         set_page_dirty(page);
 373         kunmap(page);
 374         hfs_bnode_put(node);
 375         tree->free_nodes++;
 376         mark_inode_dirty(tree->inode);
 377 }