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 pr_err("invalid btree extent records (0 size)\n"); 44 goto free_inode; 45 } 46 47 mapping = tree->inode->i_mapping; 48 page = read_mapping_page(mapping, 0, NULL); 49 if (IS_ERR(page)) 50 goto free_inode; 51 52 /* Load the header */ 53 head = (struct hfs_btree_header_rec *)(kmap(page) + 54 sizeof(struct hfs_bnode_desc)); 55 tree->root = be32_to_cpu(head->root); 56 tree->leaf_count = be32_to_cpu(head->leaf_count); 57 tree->leaf_head = be32_to_cpu(head->leaf_head); 58 tree->leaf_tail = be32_to_cpu(head->leaf_tail); 59 tree->node_count = be32_to_cpu(head->node_count); 60 tree->free_nodes = be32_to_cpu(head->free_nodes); 61 tree->attributes = be32_to_cpu(head->attributes); 62 tree->node_size = be16_to_cpu(head->node_size); 63 tree->max_key_len = be16_to_cpu(head->max_key_len); 64 tree->depth = be16_to_cpu(head->depth); 65 66 /* Verify the tree and set the correct compare function */ 67 switch (id) { 68 case HFSPLUS_EXT_CNID: 69 if (tree->max_key_len != HFSPLUS_EXT_KEYLEN - sizeof(u16)) { 70 pr_err("invalid extent max_key_len %d\n", 71 tree->max_key_len); 72 goto fail_page; 73 } 74 if (tree->attributes & HFS_TREE_VARIDXKEYS) { 75 pr_err("invalid extent btree flag\n"); 76 goto fail_page; 77 } 78 79 tree->keycmp = hfsplus_ext_cmp_key; 80 break; 81 case HFSPLUS_CAT_CNID: 82 if (tree->max_key_len != HFSPLUS_CAT_KEYLEN - sizeof(u16)) { 83 pr_err("invalid catalog max_key_len %d\n", 84 tree->max_key_len); 85 goto fail_page; 86 } 87 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) { 88 pr_err("invalid catalog btree flag\n"); 89 goto fail_page; 90 } 91 92 if (test_bit(HFSPLUS_SB_HFSX, &HFSPLUS_SB(sb)->flags) && 93 (head->key_type == HFSPLUS_KEY_BINARY)) 94 tree->keycmp = hfsplus_cat_bin_cmp_key; 95 else { 96 tree->keycmp = hfsplus_cat_case_cmp_key; 97 set_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags); 98 } 99 break; 100 case HFSPLUS_ATTR_CNID: 101 if (tree->max_key_len != HFSPLUS_ATTR_KEYLEN - sizeof(u16)) { 102 pr_err("invalid attributes max_key_len %d\n", 103 tree->max_key_len); 104 goto fail_page; 105 } 106 tree->keycmp = hfsplus_attr_bin_cmp_key; 107 break; 108 default: 109 pr_err("unknown B*Tree requested\n"); 110 goto fail_page; 111 } 112 113 if (!(tree->attributes & HFS_TREE_BIGKEYS)) { 114 pr_err("invalid btree flag\n"); 115 goto fail_page; 116 } 117 118 size = tree->node_size; 119 if (!is_power_of_2(size)) 120 goto fail_page; 121 if (!tree->node_count) 122 goto fail_page; 123 124 tree->node_size_shift = ffs(size) - 1; 125 126 tree->pages_per_bnode = 127 (tree->node_size + PAGE_CACHE_SIZE - 1) >> 128 PAGE_CACHE_SHIFT; 129 130 kunmap(page); 131 page_cache_release(page); 132 return tree; 133 134 fail_page: 135 page_cache_release(page); 136 free_inode: 137 tree->inode->i_mapping->a_ops = &hfsplus_aops; 138 iput(tree->inode); 139 free_tree: 140 kfree(tree); 141 return NULL; 142 } 143 144 /* Release resources used by a btree */ 145 void hfs_btree_close(struct hfs_btree *tree) 146 { 147 struct hfs_bnode *node; 148 int i; 149 150 if (!tree) 151 return; 152 153 for (i = 0; i < NODE_HASH_SIZE; i++) { 154 while ((node = tree->node_hash[i])) { 155 tree->node_hash[i] = node->next_hash; 156 if (atomic_read(&node->refcnt)) 157 pr_crit("node %d:%d " 158 "still has %d user(s)!\n", 159 node->tree->cnid, node->this, 160 atomic_read(&node->refcnt)); 161 hfs_bnode_free(node); 162 tree->node_hash_cnt--; 163 } 164 } 165 iput(tree->inode); 166 kfree(tree); 167 } 168 169 int hfs_btree_write(struct hfs_btree *tree) 170 { 171 struct hfs_btree_header_rec *head; 172 struct hfs_bnode *node; 173 struct page *page; 174 175 node = hfs_bnode_find(tree, 0); 176 if (IS_ERR(node)) 177 /* panic? */ 178 return -EIO; 179 /* Load the header */ 180 page = node->page[0]; 181 head = (struct hfs_btree_header_rec *)(kmap(page) + 182 sizeof(struct hfs_bnode_desc)); 183 184 head->root = cpu_to_be32(tree->root); 185 head->leaf_count = cpu_to_be32(tree->leaf_count); 186 head->leaf_head = cpu_to_be32(tree->leaf_head); 187 head->leaf_tail = cpu_to_be32(tree->leaf_tail); 188 head->node_count = cpu_to_be32(tree->node_count); 189 head->free_nodes = cpu_to_be32(tree->free_nodes); 190 head->attributes = cpu_to_be32(tree->attributes); 191 head->depth = cpu_to_be16(tree->depth); 192 193 kunmap(page); 194 set_page_dirty(page); 195 hfs_bnode_put(node); 196 return 0; 197 } 198 199 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) 200 { 201 struct hfs_btree *tree = prev->tree; 202 struct hfs_bnode *node; 203 struct hfs_bnode_desc desc; 204 __be32 cnid; 205 206 node = hfs_bnode_create(tree, idx); 207 if (IS_ERR(node)) 208 return node; 209 210 tree->free_nodes--; 211 prev->next = idx; 212 cnid = cpu_to_be32(idx); 213 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); 214 215 node->type = HFS_NODE_MAP; 216 node->num_recs = 1; 217 hfs_bnode_clear(node, 0, tree->node_size); 218 desc.next = 0; 219 desc.prev = 0; 220 desc.type = HFS_NODE_MAP; 221 desc.height = 0; 222 desc.num_recs = cpu_to_be16(1); 223 desc.reserved = 0; 224 hfs_bnode_write(node, &desc, 0, sizeof(desc)); 225 hfs_bnode_write_u16(node, 14, 0x8000); 226 hfs_bnode_write_u16(node, tree->node_size - 2, 14); 227 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); 228 229 return node; 230 } 231 232 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) 233 { 234 struct hfs_bnode *node, *next_node; 235 struct page **pagep; 236 u32 nidx, idx; 237 unsigned off; 238 u16 off16; 239 u16 len; 240 u8 *data, byte, m; 241 int i; 242 243 while (!tree->free_nodes) { 244 struct inode *inode = tree->inode; 245 struct hfsplus_inode_info *hip = HFSPLUS_I(inode); 246 u32 count; 247 int res; 248 249 res = hfsplus_file_extend(inode); 250 if (res) 251 return ERR_PTR(res); 252 hip->phys_size = inode->i_size = 253 (loff_t)hip->alloc_blocks << 254 HFSPLUS_SB(tree->sb)->alloc_blksz_shift; 255 hip->fs_blocks = 256 hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift; 257 inode_set_bytes(inode, inode->i_size); 258 count = inode->i_size >> tree->node_size_shift; 259 tree->free_nodes = count - tree->node_count; 260 tree->node_count = count; 261 } 262 263 nidx = 0; 264 node = hfs_bnode_find(tree, nidx); 265 if (IS_ERR(node)) 266 return node; 267 len = hfs_brec_lenoff(node, 2, &off16); 268 off = off16; 269 270 off += node->page_offset; 271 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 272 data = kmap(*pagep); 273 off &= ~PAGE_CACHE_MASK; 274 idx = 0; 275 276 for (;;) { 277 while (len) { 278 byte = data[off]; 279 if (byte != 0xff) { 280 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { 281 if (!(byte & m)) { 282 idx += i; 283 data[off] |= m; 284 set_page_dirty(*pagep); 285 kunmap(*pagep); 286 tree->free_nodes--; 287 mark_inode_dirty(tree->inode); 288 hfs_bnode_put(node); 289 return hfs_bnode_create(tree, 290 idx); 291 } 292 } 293 } 294 if (++off >= PAGE_CACHE_SIZE) { 295 kunmap(*pagep); 296 data = kmap(*++pagep); 297 off = 0; 298 } 299 idx += 8; 300 len--; 301 } 302 kunmap(*pagep); 303 nidx = node->next; 304 if (!nidx) { 305 hfs_dbg(BNODE_MOD, "create new bmap node\n"); 306 next_node = hfs_bmap_new_bmap(node, idx); 307 } else 308 next_node = hfs_bnode_find(tree, nidx); 309 hfs_bnode_put(node); 310 if (IS_ERR(next_node)) 311 return next_node; 312 node = next_node; 313 314 len = hfs_brec_lenoff(node, 0, &off16); 315 off = off16; 316 off += node->page_offset; 317 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 318 data = kmap(*pagep); 319 off &= ~PAGE_CACHE_MASK; 320 } 321 } 322 323 void hfs_bmap_free(struct hfs_bnode *node) 324 { 325 struct hfs_btree *tree; 326 struct page *page; 327 u16 off, len; 328 u32 nidx; 329 u8 *data, byte, m; 330 331 hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this); 332 BUG_ON(!node->this); 333 tree = node->tree; 334 nidx = node->this; 335 node = hfs_bnode_find(tree, 0); 336 if (IS_ERR(node)) 337 return; 338 len = hfs_brec_lenoff(node, 2, &off); 339 while (nidx >= len * 8) { 340 u32 i; 341 342 nidx -= len * 8; 343 i = node->next; 344 hfs_bnode_put(node); 345 if (!i) { 346 /* panic */; 347 pr_crit("unable to free bnode %u. " 348 "bmap not found!\n", 349 node->this); 350 return; 351 } 352 node = hfs_bnode_find(tree, i); 353 if (IS_ERR(node)) 354 return; 355 if (node->type != HFS_NODE_MAP) { 356 /* panic */; 357 pr_crit("invalid bmap found! " 358 "(%u,%d)\n", 359 node->this, node->type); 360 hfs_bnode_put(node); 361 return; 362 } 363 len = hfs_brec_lenoff(node, 0, &off); 364 } 365 off += node->page_offset + nidx / 8; 366 page = node->page[off >> PAGE_CACHE_SHIFT]; 367 data = kmap(page); 368 off &= ~PAGE_CACHE_MASK; 369 m = 1 << (~nidx & 7); 370 byte = data[off]; 371 if (!(byte & m)) { 372 pr_crit("trying to free free bnode " 373 "%u(%d)\n", 374 node->this, node->type); 375 kunmap(page); 376 hfs_bnode_put(node); 377 return; 378 } 379 data[off] = byte & ~m; 380 set_page_dirty(page); 381 kunmap(page); 382 hfs_bnode_put(node); 383 tree->free_nodes++; 384 mark_inode_dirty(tree->inode); 385 } 386