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