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 int 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 -EIO; 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 return 0; 190 } 191 192 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) 193 { 194 struct hfs_btree *tree = prev->tree; 195 struct hfs_bnode *node; 196 struct hfs_bnode_desc desc; 197 __be32 cnid; 198 199 node = hfs_bnode_create(tree, idx); 200 if (IS_ERR(node)) 201 return node; 202 203 tree->free_nodes--; 204 prev->next = idx; 205 cnid = cpu_to_be32(idx); 206 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); 207 208 node->type = HFS_NODE_MAP; 209 node->num_recs = 1; 210 hfs_bnode_clear(node, 0, tree->node_size); 211 desc.next = 0; 212 desc.prev = 0; 213 desc.type = HFS_NODE_MAP; 214 desc.height = 0; 215 desc.num_recs = cpu_to_be16(1); 216 desc.reserved = 0; 217 hfs_bnode_write(node, &desc, 0, sizeof(desc)); 218 hfs_bnode_write_u16(node, 14, 0x8000); 219 hfs_bnode_write_u16(node, tree->node_size - 2, 14); 220 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); 221 222 return node; 223 } 224 225 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) 226 { 227 struct hfs_bnode *node, *next_node; 228 struct page **pagep; 229 u32 nidx, idx; 230 unsigned off; 231 u16 off16; 232 u16 len; 233 u8 *data, byte, m; 234 int i; 235 236 while (!tree->free_nodes) { 237 struct inode *inode = tree->inode; 238 struct hfsplus_inode_info *hip = HFSPLUS_I(inode); 239 u32 count; 240 int res; 241 242 res = hfsplus_file_extend(inode); 243 if (res) 244 return ERR_PTR(res); 245 hip->phys_size = inode->i_size = 246 (loff_t)hip->alloc_blocks << 247 HFSPLUS_SB(tree->sb)->alloc_blksz_shift; 248 hip->fs_blocks = 249 hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift; 250 inode_set_bytes(inode, inode->i_size); 251 count = inode->i_size >> tree->node_size_shift; 252 tree->free_nodes = count - tree->node_count; 253 tree->node_count = count; 254 } 255 256 nidx = 0; 257 node = hfs_bnode_find(tree, nidx); 258 if (IS_ERR(node)) 259 return node; 260 len = hfs_brec_lenoff(node, 2, &off16); 261 off = off16; 262 263 off += node->page_offset; 264 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 265 data = kmap(*pagep); 266 off &= ~PAGE_CACHE_MASK; 267 idx = 0; 268 269 for (;;) { 270 while (len) { 271 byte = data[off]; 272 if (byte != 0xff) { 273 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { 274 if (!(byte & m)) { 275 idx += i; 276 data[off] |= m; 277 set_page_dirty(*pagep); 278 kunmap(*pagep); 279 tree->free_nodes--; 280 mark_inode_dirty(tree->inode); 281 hfs_bnode_put(node); 282 return hfs_bnode_create(tree, 283 idx); 284 } 285 } 286 } 287 if (++off >= PAGE_CACHE_SIZE) { 288 kunmap(*pagep); 289 data = kmap(*++pagep); 290 off = 0; 291 } 292 idx += 8; 293 len--; 294 } 295 kunmap(*pagep); 296 nidx = node->next; 297 if (!nidx) { 298 dprint(DBG_BNODE_MOD, "hfs: create new bmap node.\n"); 299 next_node = hfs_bmap_new_bmap(node, idx); 300 } else 301 next_node = hfs_bnode_find(tree, nidx); 302 hfs_bnode_put(node); 303 if (IS_ERR(next_node)) 304 return next_node; 305 node = next_node; 306 307 len = hfs_brec_lenoff(node, 0, &off16); 308 off = off16; 309 off += node->page_offset; 310 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 311 data = kmap(*pagep); 312 off &= ~PAGE_CACHE_MASK; 313 } 314 } 315 316 void hfs_bmap_free(struct hfs_bnode *node) 317 { 318 struct hfs_btree *tree; 319 struct page *page; 320 u16 off, len; 321 u32 nidx; 322 u8 *data, byte, m; 323 324 dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); 325 BUG_ON(!node->this); 326 tree = node->tree; 327 nidx = node->this; 328 node = hfs_bnode_find(tree, 0); 329 if (IS_ERR(node)) 330 return; 331 len = hfs_brec_lenoff(node, 2, &off); 332 while (nidx >= len * 8) { 333 u32 i; 334 335 nidx -= len * 8; 336 i = node->next; 337 hfs_bnode_put(node); 338 if (!i) { 339 /* panic */; 340 printk(KERN_CRIT "hfs: unable to free bnode %u. " 341 "bmap not found!\n", 342 node->this); 343 return; 344 } 345 node = hfs_bnode_find(tree, i); 346 if (IS_ERR(node)) 347 return; 348 if (node->type != HFS_NODE_MAP) { 349 /* panic */; 350 printk(KERN_CRIT "hfs: invalid bmap found! " 351 "(%u,%d)\n", 352 node->this, node->type); 353 hfs_bnode_put(node); 354 return; 355 } 356 len = hfs_brec_lenoff(node, 0, &off); 357 } 358 off += node->page_offset + nidx / 8; 359 page = node->page[off >> PAGE_CACHE_SHIFT]; 360 data = kmap(page); 361 off &= ~PAGE_CACHE_MASK; 362 m = 1 << (~nidx & 7); 363 byte = data[off]; 364 if (!(byte & m)) { 365 printk(KERN_CRIT "hfs: trying to free free bnode " 366 "%u(%d)\n", 367 node->this, node->type); 368 kunmap(page); 369 hfs_bnode_put(node); 370 return; 371 } 372 data[off] = byte & ~m; 373 set_page_dirty(page); 374 kunmap(page); 375 hfs_bnode_put(node); 376 tree->free_nodes++; 377 mark_inode_dirty(tree->inode); 378 } 379