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) + 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 printk(KERN_ERR "hfs: 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 printk(KERN_ERR "hfs: 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 printk(KERN_ERR "hfs: 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 printk(KERN_ERR "hfs: 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 default: 101 printk(KERN_ERR "hfs: unknown B*Tree requested\n"); 102 goto fail_page; 103 } 104 105 if (!(tree->attributes & HFS_TREE_BIGKEYS)) { 106 printk(KERN_ERR "hfs: invalid btree flag\n"); 107 goto fail_page; 108 } 109 110 size = tree->node_size; 111 if (!is_power_of_2(size)) 112 goto fail_page; 113 if (!tree->node_count) 114 goto fail_page; 115 116 tree->node_size_shift = ffs(size) - 1; 117 118 tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 119 120 kunmap(page); 121 page_cache_release(page); 122 return tree; 123 124 fail_page: 125 page_cache_release(page); 126 free_inode: 127 tree->inode->i_mapping->a_ops = &hfsplus_aops; 128 iput(tree->inode); 129 free_tree: 130 kfree(tree); 131 return NULL; 132 } 133 134 /* Release resources used by a btree */ 135 void hfs_btree_close(struct hfs_btree *tree) 136 { 137 struct hfs_bnode *node; 138 int i; 139 140 if (!tree) 141 return; 142 143 for (i = 0; i < NODE_HASH_SIZE; i++) { 144 while ((node = tree->node_hash[i])) { 145 tree->node_hash[i] = node->next_hash; 146 if (atomic_read(&node->refcnt)) 147 printk(KERN_CRIT "hfs: node %d:%d still has %d user(s)!\n", 148 node->tree->cnid, node->this, atomic_read(&node->refcnt)); 149 hfs_bnode_free(node); 150 tree->node_hash_cnt--; 151 } 152 } 153 iput(tree->inode); 154 kfree(tree); 155 } 156 157 void hfs_btree_write(struct hfs_btree *tree) 158 { 159 struct hfs_btree_header_rec *head; 160 struct hfs_bnode *node; 161 struct page *page; 162 163 node = hfs_bnode_find(tree, 0); 164 if (IS_ERR(node)) 165 /* panic? */ 166 return; 167 /* Load the header */ 168 page = node->page[0]; 169 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 170 171 head->root = cpu_to_be32(tree->root); 172 head->leaf_count = cpu_to_be32(tree->leaf_count); 173 head->leaf_head = cpu_to_be32(tree->leaf_head); 174 head->leaf_tail = cpu_to_be32(tree->leaf_tail); 175 head->node_count = cpu_to_be32(tree->node_count); 176 head->free_nodes = cpu_to_be32(tree->free_nodes); 177 head->attributes = cpu_to_be32(tree->attributes); 178 head->depth = cpu_to_be16(tree->depth); 179 180 kunmap(page); 181 set_page_dirty(page); 182 hfs_bnode_put(node); 183 } 184 185 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) 186 { 187 struct hfs_btree *tree = prev->tree; 188 struct hfs_bnode *node; 189 struct hfs_bnode_desc desc; 190 __be32 cnid; 191 192 node = hfs_bnode_create(tree, idx); 193 if (IS_ERR(node)) 194 return node; 195 196 tree->free_nodes--; 197 prev->next = idx; 198 cnid = cpu_to_be32(idx); 199 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); 200 201 node->type = HFS_NODE_MAP; 202 node->num_recs = 1; 203 hfs_bnode_clear(node, 0, tree->node_size); 204 desc.next = 0; 205 desc.prev = 0; 206 desc.type = HFS_NODE_MAP; 207 desc.height = 0; 208 desc.num_recs = cpu_to_be16(1); 209 desc.reserved = 0; 210 hfs_bnode_write(node, &desc, 0, sizeof(desc)); 211 hfs_bnode_write_u16(node, 14, 0x8000); 212 hfs_bnode_write_u16(node, tree->node_size - 2, 14); 213 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); 214 215 return node; 216 } 217 218 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) 219 { 220 struct hfs_bnode *node, *next_node; 221 struct page **pagep; 222 u32 nidx, idx; 223 unsigned off; 224 u16 off16; 225 u16 len; 226 u8 *data, byte, m; 227 int i; 228 229 while (!tree->free_nodes) { 230 struct inode *inode = tree->inode; 231 struct hfsplus_inode_info *hip = HFSPLUS_I(inode); 232 u32 count; 233 int res; 234 235 res = hfsplus_file_extend(inode); 236 if (res) 237 return ERR_PTR(res); 238 hip->phys_size = inode->i_size = 239 (loff_t)hip->alloc_blocks << 240 HFSPLUS_SB(tree->sb)->alloc_blksz_shift; 241 hip->fs_blocks = 242 hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift; 243 inode_set_bytes(inode, inode->i_size); 244 count = inode->i_size >> tree->node_size_shift; 245 tree->free_nodes = count - tree->node_count; 246 tree->node_count = count; 247 } 248 249 nidx = 0; 250 node = hfs_bnode_find(tree, nidx); 251 if (IS_ERR(node)) 252 return node; 253 len = hfs_brec_lenoff(node, 2, &off16); 254 off = off16; 255 256 off += node->page_offset; 257 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 258 data = kmap(*pagep); 259 off &= ~PAGE_CACHE_MASK; 260 idx = 0; 261 262 for (;;) { 263 while (len) { 264 byte = data[off]; 265 if (byte != 0xff) { 266 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { 267 if (!(byte & m)) { 268 idx += i; 269 data[off] |= m; 270 set_page_dirty(*pagep); 271 kunmap(*pagep); 272 tree->free_nodes--; 273 mark_inode_dirty(tree->inode); 274 hfs_bnode_put(node); 275 return hfs_bnode_create(tree, idx); 276 } 277 } 278 } 279 if (++off >= PAGE_CACHE_SIZE) { 280 kunmap(*pagep); 281 data = kmap(*++pagep); 282 off = 0; 283 } 284 idx += 8; 285 len--; 286 } 287 kunmap(*pagep); 288 nidx = node->next; 289 if (!nidx) { 290 printk(KERN_DEBUG "hfs: create new bmap node...\n"); 291 next_node = hfs_bmap_new_bmap(node, idx); 292 } else 293 next_node = hfs_bnode_find(tree, nidx); 294 hfs_bnode_put(node); 295 if (IS_ERR(next_node)) 296 return next_node; 297 node = next_node; 298 299 len = hfs_brec_lenoff(node, 0, &off16); 300 off = off16; 301 off += node->page_offset; 302 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 303 data = kmap(*pagep); 304 off &= ~PAGE_CACHE_MASK; 305 } 306 } 307 308 void hfs_bmap_free(struct hfs_bnode *node) 309 { 310 struct hfs_btree *tree; 311 struct page *page; 312 u16 off, len; 313 u32 nidx; 314 u8 *data, byte, m; 315 316 dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); 317 BUG_ON(!node->this); 318 tree = node->tree; 319 nidx = node->this; 320 node = hfs_bnode_find(tree, 0); 321 if (IS_ERR(node)) 322 return; 323 len = hfs_brec_lenoff(node, 2, &off); 324 while (nidx >= len * 8) { 325 u32 i; 326 327 nidx -= len * 8; 328 i = node->next; 329 hfs_bnode_put(node); 330 if (!i) { 331 /* panic */; 332 printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this); 333 return; 334 } 335 node = hfs_bnode_find(tree, i); 336 if (IS_ERR(node)) 337 return; 338 if (node->type != HFS_NODE_MAP) { 339 /* panic */; 340 printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type); 341 hfs_bnode_put(node); 342 return; 343 } 344 len = hfs_brec_lenoff(node, 0, &off); 345 } 346 off += node->page_offset + nidx / 8; 347 page = node->page[off >> PAGE_CACHE_SHIFT]; 348 data = kmap(page); 349 off &= ~PAGE_CACHE_MASK; 350 m = 1 << (~nidx & 7); 351 byte = data[off]; 352 if (!(byte & m)) { 353 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type); 354 kunmap(page); 355 hfs_bnode_put(node); 356 return; 357 } 358 data[off] = byte & ~m; 359 set_page_dirty(page); 360 kunmap(page); 361 hfs_bnode_put(node); 362 tree->free_nodes++; 363 mark_inode_dirty(tree->inode); 364 } 365