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 14 #include "hfsplus_fs.h" 15 #include "hfsplus_raw.h" 16 17 18 /* Get a reference to a B*Tree and do some initial checks */ 19 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id) 20 { 21 struct hfs_btree *tree; 22 struct hfs_btree_header_rec *head; 23 struct address_space *mapping; 24 struct page *page; 25 unsigned int size; 26 27 tree = kzalloc(sizeof(*tree), GFP_KERNEL); 28 if (!tree) 29 return NULL; 30 31 init_MUTEX(&tree->tree_lock); 32 spin_lock_init(&tree->hash_lock); 33 tree->sb = sb; 34 tree->cnid = id; 35 tree->inode = iget(sb, id); 36 if (!tree->inode) 37 goto free_tree; 38 39 mapping = tree->inode->i_mapping; 40 page = read_mapping_page(mapping, 0, NULL); 41 if (IS_ERR(page)) 42 goto free_tree; 43 44 /* Load the header */ 45 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 46 tree->root = be32_to_cpu(head->root); 47 tree->leaf_count = be32_to_cpu(head->leaf_count); 48 tree->leaf_head = be32_to_cpu(head->leaf_head); 49 tree->leaf_tail = be32_to_cpu(head->leaf_tail); 50 tree->node_count = be32_to_cpu(head->node_count); 51 tree->free_nodes = be32_to_cpu(head->free_nodes); 52 tree->attributes = be32_to_cpu(head->attributes); 53 tree->node_size = be16_to_cpu(head->node_size); 54 tree->max_key_len = be16_to_cpu(head->max_key_len); 55 tree->depth = be16_to_cpu(head->depth); 56 57 /* Set the correct compare function */ 58 if (id == HFSPLUS_EXT_CNID) { 59 tree->keycmp = hfsplus_ext_cmp_key; 60 } else if (id == HFSPLUS_CAT_CNID) { 61 if ((HFSPLUS_SB(sb).flags & HFSPLUS_SB_HFSX) && 62 (head->key_type == HFSPLUS_KEY_BINARY)) 63 tree->keycmp = hfsplus_cat_bin_cmp_key; 64 else 65 tree->keycmp = hfsplus_cat_case_cmp_key; 66 } else { 67 printk(KERN_ERR "hfs: unknown B*Tree requested\n"); 68 goto fail_page; 69 } 70 71 size = tree->node_size; 72 if (!size || size & (size - 1)) 73 goto fail_page; 74 if (!tree->node_count) 75 goto fail_page; 76 tree->node_size_shift = ffs(size) - 1; 77 78 tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 79 80 kunmap(page); 81 page_cache_release(page); 82 return tree; 83 84 fail_page: 85 tree->inode->i_mapping->a_ops = &hfsplus_aops; 86 page_cache_release(page); 87 free_tree: 88 iput(tree->inode); 89 kfree(tree); 90 return NULL; 91 } 92 93 /* Release resources used by a btree */ 94 void hfs_btree_close(struct hfs_btree *tree) 95 { 96 struct hfs_bnode *node; 97 int i; 98 99 if (!tree) 100 return; 101 102 for (i = 0; i < NODE_HASH_SIZE; i++) { 103 while ((node = tree->node_hash[i])) { 104 tree->node_hash[i] = node->next_hash; 105 if (atomic_read(&node->refcnt)) 106 printk(KERN_CRIT "hfs: node %d:%d still has %d user(s)!\n", 107 node->tree->cnid, node->this, atomic_read(&node->refcnt)); 108 hfs_bnode_free(node); 109 tree->node_hash_cnt--; 110 } 111 } 112 iput(tree->inode); 113 kfree(tree); 114 } 115 116 void hfs_btree_write(struct hfs_btree *tree) 117 { 118 struct hfs_btree_header_rec *head; 119 struct hfs_bnode *node; 120 struct page *page; 121 122 node = hfs_bnode_find(tree, 0); 123 if (IS_ERR(node)) 124 /* panic? */ 125 return; 126 /* Load the header */ 127 page = node->page[0]; 128 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 129 130 head->root = cpu_to_be32(tree->root); 131 head->leaf_count = cpu_to_be32(tree->leaf_count); 132 head->leaf_head = cpu_to_be32(tree->leaf_head); 133 head->leaf_tail = cpu_to_be32(tree->leaf_tail); 134 head->node_count = cpu_to_be32(tree->node_count); 135 head->free_nodes = cpu_to_be32(tree->free_nodes); 136 head->attributes = cpu_to_be32(tree->attributes); 137 head->depth = cpu_to_be16(tree->depth); 138 139 kunmap(page); 140 set_page_dirty(page); 141 hfs_bnode_put(node); 142 } 143 144 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) 145 { 146 struct hfs_btree *tree = prev->tree; 147 struct hfs_bnode *node; 148 struct hfs_bnode_desc desc; 149 __be32 cnid; 150 151 node = hfs_bnode_create(tree, idx); 152 if (IS_ERR(node)) 153 return node; 154 155 tree->free_nodes--; 156 prev->next = idx; 157 cnid = cpu_to_be32(idx); 158 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); 159 160 node->type = HFS_NODE_MAP; 161 node->num_recs = 1; 162 hfs_bnode_clear(node, 0, tree->node_size); 163 desc.next = 0; 164 desc.prev = 0; 165 desc.type = HFS_NODE_MAP; 166 desc.height = 0; 167 desc.num_recs = cpu_to_be16(1); 168 desc.reserved = 0; 169 hfs_bnode_write(node, &desc, 0, sizeof(desc)); 170 hfs_bnode_write_u16(node, 14, 0x8000); 171 hfs_bnode_write_u16(node, tree->node_size - 2, 14); 172 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); 173 174 return node; 175 } 176 177 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) 178 { 179 struct hfs_bnode *node, *next_node; 180 struct page **pagep; 181 u32 nidx, idx; 182 u16 off, len; 183 u8 *data, byte, m; 184 int i; 185 186 while (!tree->free_nodes) { 187 struct inode *inode = tree->inode; 188 u32 count; 189 int res; 190 191 res = hfsplus_file_extend(inode); 192 if (res) 193 return ERR_PTR(res); 194 HFSPLUS_I(inode).phys_size = inode->i_size = 195 (loff_t)HFSPLUS_I(inode).alloc_blocks << 196 HFSPLUS_SB(tree->sb).alloc_blksz_shift; 197 HFSPLUS_I(inode).fs_blocks = HFSPLUS_I(inode).alloc_blocks << 198 HFSPLUS_SB(tree->sb).fs_shift; 199 inode_set_bytes(inode, inode->i_size); 200 count = inode->i_size >> tree->node_size_shift; 201 tree->free_nodes = count - tree->node_count; 202 tree->node_count = count; 203 } 204 205 nidx = 0; 206 node = hfs_bnode_find(tree, nidx); 207 if (IS_ERR(node)) 208 return node; 209 len = hfs_brec_lenoff(node, 2, &off); 210 211 off += node->page_offset; 212 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 213 data = kmap(*pagep); 214 off &= ~PAGE_CACHE_MASK; 215 idx = 0; 216 217 for (;;) { 218 while (len) { 219 byte = data[off]; 220 if (byte != 0xff) { 221 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { 222 if (!(byte & m)) { 223 idx += i; 224 data[off] |= m; 225 set_page_dirty(*pagep); 226 kunmap(*pagep); 227 tree->free_nodes--; 228 mark_inode_dirty(tree->inode); 229 hfs_bnode_put(node); 230 return hfs_bnode_create(tree, idx); 231 } 232 } 233 } 234 if (++off >= PAGE_CACHE_SIZE) { 235 kunmap(*pagep); 236 data = kmap(*++pagep); 237 off = 0; 238 } 239 idx += 8; 240 len--; 241 } 242 kunmap(*pagep); 243 nidx = node->next; 244 if (!nidx) { 245 printk(KERN_DEBUG "hfs: create new bmap node...\n"); 246 next_node = hfs_bmap_new_bmap(node, idx); 247 } else 248 next_node = hfs_bnode_find(tree, nidx); 249 hfs_bnode_put(node); 250 if (IS_ERR(next_node)) 251 return next_node; 252 node = next_node; 253 254 len = hfs_brec_lenoff(node, 0, &off); 255 off += node->page_offset; 256 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 257 data = kmap(*pagep); 258 off &= ~PAGE_CACHE_MASK; 259 } 260 } 261 262 void hfs_bmap_free(struct hfs_bnode *node) 263 { 264 struct hfs_btree *tree; 265 struct page *page; 266 u16 off, len; 267 u32 nidx; 268 u8 *data, byte, m; 269 270 dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); 271 BUG_ON(!node->this); 272 tree = node->tree; 273 nidx = node->this; 274 node = hfs_bnode_find(tree, 0); 275 if (IS_ERR(node)) 276 return; 277 len = hfs_brec_lenoff(node, 2, &off); 278 while (nidx >= len * 8) { 279 u32 i; 280 281 nidx -= len * 8; 282 i = node->next; 283 hfs_bnode_put(node); 284 if (!i) { 285 /* panic */; 286 printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this); 287 return; 288 } 289 node = hfs_bnode_find(tree, i); 290 if (IS_ERR(node)) 291 return; 292 if (node->type != HFS_NODE_MAP) { 293 /* panic */; 294 printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type); 295 hfs_bnode_put(node); 296 return; 297 } 298 len = hfs_brec_lenoff(node, 0, &off); 299 } 300 off += node->page_offset + nidx / 8; 301 page = node->page[off >> PAGE_CACHE_SHIFT]; 302 data = kmap(page); 303 off &= ~PAGE_CACHE_MASK; 304 m = 1 << (~nidx & 7); 305 byte = data[off]; 306 if (!(byte & m)) { 307 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type); 308 kunmap(page); 309 hfs_bnode_put(node); 310 return; 311 } 312 data[off] = byte & ~m; 313 set_page_dirty(page); 314 kunmap(page); 315 hfs_bnode_put(node); 316 tree->free_nodes++; 317 mark_inode_dirty(tree->inode); 318 } 319