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 } 378