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