1 /* 2 * linux/fs/hfs/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/pagemap.h> 12 #include <linux/log2.h> 13 14 #include "btree.h" 15 16 /* Get a reference to a B*Tree and do some initial checks */ 17 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp) 18 { 19 struct hfs_btree *tree; 20 struct hfs_btree_header_rec *head; 21 struct address_space *mapping; 22 struct page *page; 23 unsigned int size; 24 25 tree = kzalloc(sizeof(*tree), GFP_KERNEL); 26 if (!tree) 27 return NULL; 28 29 init_MUTEX(&tree->tree_lock); 30 spin_lock_init(&tree->hash_lock); 31 /* Set the correct compare function */ 32 tree->sb = sb; 33 tree->cnid = id; 34 tree->keycmp = keycmp; 35 36 tree->inode = iget_locked(sb, id); 37 if (!tree->inode) 38 goto free_tree; 39 BUG_ON(!(tree->inode->i_state & I_NEW)); 40 { 41 struct hfs_mdb *mdb = HFS_SB(sb)->mdb; 42 HFS_I(tree->inode)->flags = 0; 43 mutex_init(&HFS_I(tree->inode)->extents_lock); 44 switch (id) { 45 case HFS_EXT_CNID: 46 hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize, 47 mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz)); 48 tree->inode->i_mapping->a_ops = &hfs_btree_aops; 49 break; 50 case HFS_CAT_CNID: 51 hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize, 52 mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz)); 53 tree->inode->i_mapping->a_ops = &hfs_btree_aops; 54 break; 55 default: 56 BUG(); 57 } 58 } 59 unlock_new_inode(tree->inode); 60 61 if (!HFS_I(tree->inode)->first_blocks) { 62 printk(KERN_ERR "hfs: invalid btree extent records (0 size).\n"); 63 goto free_inode; 64 } 65 66 mapping = tree->inode->i_mapping; 67 page = read_mapping_page(mapping, 0, NULL); 68 if (IS_ERR(page)) 69 goto free_inode; 70 71 /* Load the header */ 72 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 73 tree->root = be32_to_cpu(head->root); 74 tree->leaf_count = be32_to_cpu(head->leaf_count); 75 tree->leaf_head = be32_to_cpu(head->leaf_head); 76 tree->leaf_tail = be32_to_cpu(head->leaf_tail); 77 tree->node_count = be32_to_cpu(head->node_count); 78 tree->free_nodes = be32_to_cpu(head->free_nodes); 79 tree->attributes = be32_to_cpu(head->attributes); 80 tree->node_size = be16_to_cpu(head->node_size); 81 tree->max_key_len = be16_to_cpu(head->max_key_len); 82 tree->depth = be16_to_cpu(head->depth); 83 84 size = tree->node_size; 85 if (!is_power_of_2(size)) 86 goto fail_page; 87 if (!tree->node_count) 88 goto fail_page; 89 switch (id) { 90 case HFS_EXT_CNID: 91 if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) { 92 printk(KERN_ERR "hfs: invalid extent max_key_len %d\n", 93 tree->max_key_len); 94 goto fail_page; 95 } 96 break; 97 case HFS_CAT_CNID: 98 if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) { 99 printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n", 100 tree->max_key_len); 101 goto fail_page; 102 } 103 break; 104 default: 105 BUG(); 106 } 107 108 tree->node_size_shift = ffs(size) - 1; 109 tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 110 111 kunmap(page); 112 page_cache_release(page); 113 return tree; 114 115 fail_page: 116 page_cache_release(page); 117 free_inode: 118 tree->inode->i_mapping->a_ops = &hfs_aops; 119 iput(tree->inode); 120 free_tree: 121 kfree(tree); 122 return NULL; 123 } 124 125 /* Release resources used by a btree */ 126 void hfs_btree_close(struct hfs_btree *tree) 127 { 128 struct hfs_bnode *node; 129 int i; 130 131 if (!tree) 132 return; 133 134 for (i = 0; i < NODE_HASH_SIZE; i++) { 135 while ((node = tree->node_hash[i])) { 136 tree->node_hash[i] = node->next_hash; 137 if (atomic_read(&node->refcnt)) 138 printk(KERN_ERR "hfs: node %d:%d still has %d user(s)!\n", 139 node->tree->cnid, node->this, atomic_read(&node->refcnt)); 140 hfs_bnode_free(node); 141 tree->node_hash_cnt--; 142 } 143 } 144 iput(tree->inode); 145 kfree(tree); 146 } 147 148 void hfs_btree_write(struct hfs_btree *tree) 149 { 150 struct hfs_btree_header_rec *head; 151 struct hfs_bnode *node; 152 struct page *page; 153 154 node = hfs_bnode_find(tree, 0); 155 if (IS_ERR(node)) 156 /* panic? */ 157 return; 158 /* Load the header */ 159 page = node->page[0]; 160 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 161 162 head->root = cpu_to_be32(tree->root); 163 head->leaf_count = cpu_to_be32(tree->leaf_count); 164 head->leaf_head = cpu_to_be32(tree->leaf_head); 165 head->leaf_tail = cpu_to_be32(tree->leaf_tail); 166 head->node_count = cpu_to_be32(tree->node_count); 167 head->free_nodes = cpu_to_be32(tree->free_nodes); 168 head->attributes = cpu_to_be32(tree->attributes); 169 head->depth = cpu_to_be16(tree->depth); 170 171 kunmap(page); 172 set_page_dirty(page); 173 hfs_bnode_put(node); 174 } 175 176 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) 177 { 178 struct hfs_btree *tree = prev->tree; 179 struct hfs_bnode *node; 180 struct hfs_bnode_desc desc; 181 __be32 cnid; 182 183 node = hfs_bnode_create(tree, idx); 184 if (IS_ERR(node)) 185 return node; 186 187 if (!tree->free_nodes) 188 panic("FIXME!!!"); 189 tree->free_nodes--; 190 prev->next = idx; 191 cnid = cpu_to_be32(idx); 192 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); 193 194 node->type = HFS_NODE_MAP; 195 node->num_recs = 1; 196 hfs_bnode_clear(node, 0, tree->node_size); 197 desc.next = 0; 198 desc.prev = 0; 199 desc.type = HFS_NODE_MAP; 200 desc.height = 0; 201 desc.num_recs = cpu_to_be16(1); 202 desc.reserved = 0; 203 hfs_bnode_write(node, &desc, 0, sizeof(desc)); 204 hfs_bnode_write_u16(node, 14, 0x8000); 205 hfs_bnode_write_u16(node, tree->node_size - 2, 14); 206 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); 207 208 return node; 209 } 210 211 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) 212 { 213 struct hfs_bnode *node, *next_node; 214 struct page **pagep; 215 u32 nidx, idx; 216 unsigned off; 217 u16 off16; 218 u16 len; 219 u8 *data, byte, m; 220 int i; 221 222 while (!tree->free_nodes) { 223 struct inode *inode = tree->inode; 224 u32 count; 225 int res; 226 227 res = hfs_extend_file(inode); 228 if (res) 229 return ERR_PTR(res); 230 HFS_I(inode)->phys_size = inode->i_size = 231 (loff_t)HFS_I(inode)->alloc_blocks * 232 HFS_SB(tree->sb)->alloc_blksz; 233 HFS_I(inode)->fs_blocks = inode->i_size >> 234 tree->sb->s_blocksize_bits; 235 inode_set_bytes(inode, inode->i_size); 236 count = inode->i_size >> tree->node_size_shift; 237 tree->free_nodes = count - tree->node_count; 238 tree->node_count = count; 239 } 240 241 nidx = 0; 242 node = hfs_bnode_find(tree, nidx); 243 if (IS_ERR(node)) 244 return node; 245 len = hfs_brec_lenoff(node, 2, &off16); 246 off = off16; 247 248 off += node->page_offset; 249 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 250 data = kmap(*pagep); 251 off &= ~PAGE_CACHE_MASK; 252 idx = 0; 253 254 for (;;) { 255 while (len) { 256 byte = data[off]; 257 if (byte != 0xff) { 258 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { 259 if (!(byte & m)) { 260 idx += i; 261 data[off] |= m; 262 set_page_dirty(*pagep); 263 kunmap(*pagep); 264 tree->free_nodes--; 265 mark_inode_dirty(tree->inode); 266 hfs_bnode_put(node); 267 return hfs_bnode_create(tree, idx); 268 } 269 } 270 } 271 if (++off >= PAGE_CACHE_SIZE) { 272 kunmap(*pagep); 273 data = kmap(*++pagep); 274 off = 0; 275 } 276 idx += 8; 277 len--; 278 } 279 kunmap(*pagep); 280 nidx = node->next; 281 if (!nidx) { 282 printk(KERN_DEBUG "hfs: create new bmap node...\n"); 283 next_node = hfs_bmap_new_bmap(node, idx); 284 } else 285 next_node = hfs_bnode_find(tree, nidx); 286 hfs_bnode_put(node); 287 if (IS_ERR(next_node)) 288 return next_node; 289 node = next_node; 290 291 len = hfs_brec_lenoff(node, 0, &off16); 292 off = off16; 293 off += node->page_offset; 294 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 295 data = kmap(*pagep); 296 off &= ~PAGE_CACHE_MASK; 297 } 298 } 299 300 void hfs_bmap_free(struct hfs_bnode *node) 301 { 302 struct hfs_btree *tree; 303 struct page *page; 304 u16 off, len; 305 u32 nidx; 306 u8 *data, byte, m; 307 308 dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); 309 tree = node->tree; 310 nidx = node->this; 311 node = hfs_bnode_find(tree, 0); 312 if (IS_ERR(node)) 313 return; 314 len = hfs_brec_lenoff(node, 2, &off); 315 while (nidx >= len * 8) { 316 u32 i; 317 318 nidx -= len * 8; 319 i = node->next; 320 hfs_bnode_put(node); 321 if (!i) { 322 /* panic */; 323 printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this); 324 return; 325 } 326 node = hfs_bnode_find(tree, i); 327 if (IS_ERR(node)) 328 return; 329 if (node->type != HFS_NODE_MAP) { 330 /* panic */; 331 printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type); 332 hfs_bnode_put(node); 333 return; 334 } 335 len = hfs_brec_lenoff(node, 0, &off); 336 } 337 off += node->page_offset + nidx / 8; 338 page = node->page[off >> PAGE_CACHE_SHIFT]; 339 data = kmap(page); 340 off &= ~PAGE_CACHE_MASK; 341 m = 1 << (~nidx & 7); 342 byte = data[off]; 343 if (!(byte & m)) { 344 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type); 345 kunmap(page); 346 hfs_bnode_put(node); 347 return; 348 } 349 data[off] = byte & ~m; 350 set_page_dirty(page); 351 kunmap(page); 352 hfs_bnode_put(node); 353 tree->free_nodes++; 354 mark_inode_dirty(tree->inode); 355 } 356