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 page *page; 26 unsigned int size; 27 28 tree = kzalloc(sizeof(*tree), GFP_KERNEL); 29 if (!tree) 30 return NULL; 31 32 init_MUTEX(&tree->tree_lock); 33 spin_lock_init(&tree->hash_lock); 34 tree->sb = sb; 35 tree->cnid = id; 36 tree->inode = iget(sb, id); 37 if (!tree->inode) 38 goto free_tree; 39 40 mapping = tree->inode->i_mapping; 41 page = read_mapping_page(mapping, 0, NULL); 42 if (IS_ERR(page)) 43 goto free_tree; 44 45 /* Load the header */ 46 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 47 tree->root = be32_to_cpu(head->root); 48 tree->leaf_count = be32_to_cpu(head->leaf_count); 49 tree->leaf_head = be32_to_cpu(head->leaf_head); 50 tree->leaf_tail = be32_to_cpu(head->leaf_tail); 51 tree->node_count = be32_to_cpu(head->node_count); 52 tree->free_nodes = be32_to_cpu(head->free_nodes); 53 tree->attributes = be32_to_cpu(head->attributes); 54 tree->node_size = be16_to_cpu(head->node_size); 55 tree->max_key_len = be16_to_cpu(head->max_key_len); 56 tree->depth = be16_to_cpu(head->depth); 57 58 /* Set the correct compare function */ 59 if (id == HFSPLUS_EXT_CNID) { 60 tree->keycmp = hfsplus_ext_cmp_key; 61 } else if (id == HFSPLUS_CAT_CNID) { 62 if ((HFSPLUS_SB(sb).flags & HFSPLUS_SB_HFSX) && 63 (head->key_type == HFSPLUS_KEY_BINARY)) 64 tree->keycmp = hfsplus_cat_bin_cmp_key; 65 else { 66 tree->keycmp = hfsplus_cat_case_cmp_key; 67 HFSPLUS_SB(sb).flags |= HFSPLUS_SB_CASEFOLD; 68 } 69 } else { 70 printk(KERN_ERR "hfs: unknown B*Tree requested\n"); 71 goto fail_page; 72 } 73 74 size = tree->node_size; 75 if (!is_power_of_2(size)) 76 goto fail_page; 77 if (!tree->node_count) 78 goto fail_page; 79 tree->node_size_shift = ffs(size) - 1; 80 81 tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 82 83 kunmap(page); 84 page_cache_release(page); 85 return tree; 86 87 fail_page: 88 tree->inode->i_mapping->a_ops = &hfsplus_aops; 89 page_cache_release(page); 90 free_tree: 91 iput(tree->inode); 92 kfree(tree); 93 return NULL; 94 } 95 96 /* Release resources used by a btree */ 97 void hfs_btree_close(struct hfs_btree *tree) 98 { 99 struct hfs_bnode *node; 100 int i; 101 102 if (!tree) 103 return; 104 105 for (i = 0; i < NODE_HASH_SIZE; i++) { 106 while ((node = tree->node_hash[i])) { 107 tree->node_hash[i] = node->next_hash; 108 if (atomic_read(&node->refcnt)) 109 printk(KERN_CRIT "hfs: node %d:%d still has %d user(s)!\n", 110 node->tree->cnid, node->this, atomic_read(&node->refcnt)); 111 hfs_bnode_free(node); 112 tree->node_hash_cnt--; 113 } 114 } 115 iput(tree->inode); 116 kfree(tree); 117 } 118 119 void hfs_btree_write(struct hfs_btree *tree) 120 { 121 struct hfs_btree_header_rec *head; 122 struct hfs_bnode *node; 123 struct page *page; 124 125 node = hfs_bnode_find(tree, 0); 126 if (IS_ERR(node)) 127 /* panic? */ 128 return; 129 /* Load the header */ 130 page = node->page[0]; 131 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 132 133 head->root = cpu_to_be32(tree->root); 134 head->leaf_count = cpu_to_be32(tree->leaf_count); 135 head->leaf_head = cpu_to_be32(tree->leaf_head); 136 head->leaf_tail = cpu_to_be32(tree->leaf_tail); 137 head->node_count = cpu_to_be32(tree->node_count); 138 head->free_nodes = cpu_to_be32(tree->free_nodes); 139 head->attributes = cpu_to_be32(tree->attributes); 140 head->depth = cpu_to_be16(tree->depth); 141 142 kunmap(page); 143 set_page_dirty(page); 144 hfs_bnode_put(node); 145 } 146 147 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) 148 { 149 struct hfs_btree *tree = prev->tree; 150 struct hfs_bnode *node; 151 struct hfs_bnode_desc desc; 152 __be32 cnid; 153 154 node = hfs_bnode_create(tree, idx); 155 if (IS_ERR(node)) 156 return node; 157 158 tree->free_nodes--; 159 prev->next = idx; 160 cnid = cpu_to_be32(idx); 161 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); 162 163 node->type = HFS_NODE_MAP; 164 node->num_recs = 1; 165 hfs_bnode_clear(node, 0, tree->node_size); 166 desc.next = 0; 167 desc.prev = 0; 168 desc.type = HFS_NODE_MAP; 169 desc.height = 0; 170 desc.num_recs = cpu_to_be16(1); 171 desc.reserved = 0; 172 hfs_bnode_write(node, &desc, 0, sizeof(desc)); 173 hfs_bnode_write_u16(node, 14, 0x8000); 174 hfs_bnode_write_u16(node, tree->node_size - 2, 14); 175 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); 176 177 return node; 178 } 179 180 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) 181 { 182 struct hfs_bnode *node, *next_node; 183 struct page **pagep; 184 u32 nidx, idx; 185 u16 off, len; 186 u8 *data, byte, m; 187 int i; 188 189 while (!tree->free_nodes) { 190 struct inode *inode = tree->inode; 191 u32 count; 192 int res; 193 194 res = hfsplus_file_extend(inode); 195 if (res) 196 return ERR_PTR(res); 197 HFSPLUS_I(inode).phys_size = inode->i_size = 198 (loff_t)HFSPLUS_I(inode).alloc_blocks << 199 HFSPLUS_SB(tree->sb).alloc_blksz_shift; 200 HFSPLUS_I(inode).fs_blocks = HFSPLUS_I(inode).alloc_blocks << 201 HFSPLUS_SB(tree->sb).fs_shift; 202 inode_set_bytes(inode, inode->i_size); 203 count = inode->i_size >> tree->node_size_shift; 204 tree->free_nodes = count - tree->node_count; 205 tree->node_count = count; 206 } 207 208 nidx = 0; 209 node = hfs_bnode_find(tree, nidx); 210 if (IS_ERR(node)) 211 return node; 212 len = hfs_brec_lenoff(node, 2, &off); 213 214 off += node->page_offset; 215 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 216 data = kmap(*pagep); 217 off &= ~PAGE_CACHE_MASK; 218 idx = 0; 219 220 for (;;) { 221 while (len) { 222 byte = data[off]; 223 if (byte != 0xff) { 224 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { 225 if (!(byte & m)) { 226 idx += i; 227 data[off] |= m; 228 set_page_dirty(*pagep); 229 kunmap(*pagep); 230 tree->free_nodes--; 231 mark_inode_dirty(tree->inode); 232 hfs_bnode_put(node); 233 return hfs_bnode_create(tree, idx); 234 } 235 } 236 } 237 if (++off >= PAGE_CACHE_SIZE) { 238 kunmap(*pagep); 239 data = kmap(*++pagep); 240 off = 0; 241 } 242 idx += 8; 243 len--; 244 } 245 kunmap(*pagep); 246 nidx = node->next; 247 if (!nidx) { 248 printk(KERN_DEBUG "hfs: create new bmap node...\n"); 249 next_node = hfs_bmap_new_bmap(node, idx); 250 } else 251 next_node = hfs_bnode_find(tree, nidx); 252 hfs_bnode_put(node); 253 if (IS_ERR(next_node)) 254 return next_node; 255 node = next_node; 256 257 len = hfs_brec_lenoff(node, 0, &off); 258 off += node->page_offset; 259 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 260 data = kmap(*pagep); 261 off &= ~PAGE_CACHE_MASK; 262 } 263 } 264 265 void hfs_bmap_free(struct hfs_bnode *node) 266 { 267 struct hfs_btree *tree; 268 struct page *page; 269 u16 off, len; 270 u32 nidx; 271 u8 *data, byte, m; 272 273 dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); 274 BUG_ON(!node->this); 275 tree = node->tree; 276 nidx = node->this; 277 node = hfs_bnode_find(tree, 0); 278 if (IS_ERR(node)) 279 return; 280 len = hfs_brec_lenoff(node, 2, &off); 281 while (nidx >= len * 8) { 282 u32 i; 283 284 nidx -= len * 8; 285 i = node->next; 286 hfs_bnode_put(node); 287 if (!i) { 288 /* panic */; 289 printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this); 290 return; 291 } 292 node = hfs_bnode_find(tree, i); 293 if (IS_ERR(node)) 294 return; 295 if (node->type != HFS_NODE_MAP) { 296 /* panic */; 297 printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type); 298 hfs_bnode_put(node); 299 return; 300 } 301 len = hfs_brec_lenoff(node, 0, &off); 302 } 303 off += node->page_offset + nidx / 8; 304 page = node->page[off >> PAGE_CACHE_SHIFT]; 305 data = kmap(page); 306 off &= ~PAGE_CACHE_MASK; 307 m = 1 << (~nidx & 7); 308 byte = data[off]; 309 if (!(byte & m)) { 310 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type); 311 kunmap(page); 312 hfs_bnode_put(node); 313 return; 314 } 315 data[off] = byte & ~m; 316 set_page_dirty(page); 317 kunmap(page); 318 hfs_bnode_put(node); 319 tree->free_nodes++; 320 mark_inode_dirty(tree->inode); 321 } 322