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 case HFSPLUS_ATTR_CNID: 102 if (tree->max_key_len != HFSPLUS_ATTR_KEYLEN - sizeof(u16)) { 103 printk(KERN_ERR "hfs: invalid attributes max_key_len %d\n", 104 tree->max_key_len); 105 goto fail_page; 106 } 107 tree->keycmp = hfsplus_attr_bin_cmp_key; 108 break; 109 default: 110 printk(KERN_ERR "hfs: unknown B*Tree requested\n"); 111 goto fail_page; 112 } 113 114 if (!(tree->attributes & HFS_TREE_BIGKEYS)) { 115 printk(KERN_ERR "hfs: invalid btree flag\n"); 116 goto fail_page; 117 } 118 119 size = tree->node_size; 120 if (!is_power_of_2(size)) 121 goto fail_page; 122 if (!tree->node_count) 123 goto fail_page; 124 125 tree->node_size_shift = ffs(size) - 1; 126 127 tree->pages_per_bnode = 128 (tree->node_size + PAGE_CACHE_SIZE - 1) >> 129 PAGE_CACHE_SHIFT; 130 131 kunmap(page); 132 page_cache_release(page); 133 return tree; 134 135 fail_page: 136 page_cache_release(page); 137 free_inode: 138 tree->inode->i_mapping->a_ops = &hfsplus_aops; 139 iput(tree->inode); 140 free_tree: 141 kfree(tree); 142 return NULL; 143 } 144 145 /* Release resources used by a btree */ 146 void hfs_btree_close(struct hfs_btree *tree) 147 { 148 struct hfs_bnode *node; 149 int i; 150 151 if (!tree) 152 return; 153 154 for (i = 0; i < NODE_HASH_SIZE; i++) { 155 while ((node = tree->node_hash[i])) { 156 tree->node_hash[i] = node->next_hash; 157 if (atomic_read(&node->refcnt)) 158 printk(KERN_CRIT "hfs: node %d:%d " 159 "still has %d user(s)!\n", 160 node->tree->cnid, node->this, 161 atomic_read(&node->refcnt)); 162 hfs_bnode_free(node); 163 tree->node_hash_cnt--; 164 } 165 } 166 iput(tree->inode); 167 kfree(tree); 168 } 169 170 int hfs_btree_write(struct hfs_btree *tree) 171 { 172 struct hfs_btree_header_rec *head; 173 struct hfs_bnode *node; 174 struct page *page; 175 176 node = hfs_bnode_find(tree, 0); 177 if (IS_ERR(node)) 178 /* panic? */ 179 return -EIO; 180 /* Load the header */ 181 page = node->page[0]; 182 head = (struct hfs_btree_header_rec *)(kmap(page) + 183 sizeof(struct hfs_bnode_desc)); 184 185 head->root = cpu_to_be32(tree->root); 186 head->leaf_count = cpu_to_be32(tree->leaf_count); 187 head->leaf_head = cpu_to_be32(tree->leaf_head); 188 head->leaf_tail = cpu_to_be32(tree->leaf_tail); 189 head->node_count = cpu_to_be32(tree->node_count); 190 head->free_nodes = cpu_to_be32(tree->free_nodes); 191 head->attributes = cpu_to_be32(tree->attributes); 192 head->depth = cpu_to_be16(tree->depth); 193 194 kunmap(page); 195 set_page_dirty(page); 196 hfs_bnode_put(node); 197 return 0; 198 } 199 200 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) 201 { 202 struct hfs_btree *tree = prev->tree; 203 struct hfs_bnode *node; 204 struct hfs_bnode_desc desc; 205 __be32 cnid; 206 207 node = hfs_bnode_create(tree, idx); 208 if (IS_ERR(node)) 209 return node; 210 211 tree->free_nodes--; 212 prev->next = idx; 213 cnid = cpu_to_be32(idx); 214 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); 215 216 node->type = HFS_NODE_MAP; 217 node->num_recs = 1; 218 hfs_bnode_clear(node, 0, tree->node_size); 219 desc.next = 0; 220 desc.prev = 0; 221 desc.type = HFS_NODE_MAP; 222 desc.height = 0; 223 desc.num_recs = cpu_to_be16(1); 224 desc.reserved = 0; 225 hfs_bnode_write(node, &desc, 0, sizeof(desc)); 226 hfs_bnode_write_u16(node, 14, 0x8000); 227 hfs_bnode_write_u16(node, tree->node_size - 2, 14); 228 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); 229 230 return node; 231 } 232 233 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) 234 { 235 struct hfs_bnode *node, *next_node; 236 struct page **pagep; 237 u32 nidx, idx; 238 unsigned off; 239 u16 off16; 240 u16 len; 241 u8 *data, byte, m; 242 int i; 243 244 while (!tree->free_nodes) { 245 struct inode *inode = tree->inode; 246 struct hfsplus_inode_info *hip = HFSPLUS_I(inode); 247 u32 count; 248 int res; 249 250 res = hfsplus_file_extend(inode); 251 if (res) 252 return ERR_PTR(res); 253 hip->phys_size = inode->i_size = 254 (loff_t)hip->alloc_blocks << 255 HFSPLUS_SB(tree->sb)->alloc_blksz_shift; 256 hip->fs_blocks = 257 hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift; 258 inode_set_bytes(inode, inode->i_size); 259 count = inode->i_size >> tree->node_size_shift; 260 tree->free_nodes = count - tree->node_count; 261 tree->node_count = count; 262 } 263 264 nidx = 0; 265 node = hfs_bnode_find(tree, nidx); 266 if (IS_ERR(node)) 267 return node; 268 len = hfs_brec_lenoff(node, 2, &off16); 269 off = off16; 270 271 off += node->page_offset; 272 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 273 data = kmap(*pagep); 274 off &= ~PAGE_CACHE_MASK; 275 idx = 0; 276 277 for (;;) { 278 while (len) { 279 byte = data[off]; 280 if (byte != 0xff) { 281 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { 282 if (!(byte & m)) { 283 idx += i; 284 data[off] |= m; 285 set_page_dirty(*pagep); 286 kunmap(*pagep); 287 tree->free_nodes--; 288 mark_inode_dirty(tree->inode); 289 hfs_bnode_put(node); 290 return hfs_bnode_create(tree, 291 idx); 292 } 293 } 294 } 295 if (++off >= PAGE_CACHE_SIZE) { 296 kunmap(*pagep); 297 data = kmap(*++pagep); 298 off = 0; 299 } 300 idx += 8; 301 len--; 302 } 303 kunmap(*pagep); 304 nidx = node->next; 305 if (!nidx) { 306 dprint(DBG_BNODE_MOD, "hfs: create new bmap node.\n"); 307 next_node = hfs_bmap_new_bmap(node, idx); 308 } else 309 next_node = hfs_bnode_find(tree, nidx); 310 hfs_bnode_put(node); 311 if (IS_ERR(next_node)) 312 return next_node; 313 node = next_node; 314 315 len = hfs_brec_lenoff(node, 0, &off16); 316 off = off16; 317 off += node->page_offset; 318 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 319 data = kmap(*pagep); 320 off &= ~PAGE_CACHE_MASK; 321 } 322 } 323 324 void hfs_bmap_free(struct hfs_bnode *node) 325 { 326 struct hfs_btree *tree; 327 struct page *page; 328 u16 off, len; 329 u32 nidx; 330 u8 *data, byte, m; 331 332 dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); 333 BUG_ON(!node->this); 334 tree = node->tree; 335 nidx = node->this; 336 node = hfs_bnode_find(tree, 0); 337 if (IS_ERR(node)) 338 return; 339 len = hfs_brec_lenoff(node, 2, &off); 340 while (nidx >= len * 8) { 341 u32 i; 342 343 nidx -= len * 8; 344 i = node->next; 345 hfs_bnode_put(node); 346 if (!i) { 347 /* panic */; 348 printk(KERN_CRIT "hfs: unable to free bnode %u. " 349 "bmap not found!\n", 350 node->this); 351 return; 352 } 353 node = hfs_bnode_find(tree, i); 354 if (IS_ERR(node)) 355 return; 356 if (node->type != HFS_NODE_MAP) { 357 /* panic */; 358 printk(KERN_CRIT "hfs: invalid bmap found! " 359 "(%u,%d)\n", 360 node->this, node->type); 361 hfs_bnode_put(node); 362 return; 363 } 364 len = hfs_brec_lenoff(node, 0, &off); 365 } 366 off += node->page_offset + nidx / 8; 367 page = node->page[off >> PAGE_CACHE_SHIFT]; 368 data = kmap(page); 369 off &= ~PAGE_CACHE_MASK; 370 m = 1 << (~nidx & 7); 371 byte = data[off]; 372 if (!(byte & m)) { 373 printk(KERN_CRIT "hfs: trying to free free bnode " 374 "%u(%d)\n", 375 node->this, node->type); 376 kunmap(page); 377 hfs_bnode_put(node); 378 return; 379 } 380 data[off] = byte & ~m; 381 set_page_dirty(page); 382 kunmap(page); 383 hfs_bnode_put(node); 384 tree->free_nodes++; 385 mark_inode_dirty(tree->inode); 386 } 387