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 init_MUTEX(&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 mapping = tree->inode->i_mapping; 62 page = read_mapping_page(mapping, 0, NULL); 63 if (IS_ERR(page)) 64 goto free_inode; 65 66 /* Load the header */ 67 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 68 tree->root = be32_to_cpu(head->root); 69 tree->leaf_count = be32_to_cpu(head->leaf_count); 70 tree->leaf_head = be32_to_cpu(head->leaf_head); 71 tree->leaf_tail = be32_to_cpu(head->leaf_tail); 72 tree->node_count = be32_to_cpu(head->node_count); 73 tree->free_nodes = be32_to_cpu(head->free_nodes); 74 tree->attributes = be32_to_cpu(head->attributes); 75 tree->node_size = be16_to_cpu(head->node_size); 76 tree->max_key_len = be16_to_cpu(head->max_key_len); 77 tree->depth = be16_to_cpu(head->depth); 78 79 size = tree->node_size; 80 if (!is_power_of_2(size)) 81 goto fail_page; 82 if (!tree->node_count) 83 goto fail_page; 84 if ((id == HFS_EXT_CNID) && (tree->max_key_len != HFS_MAX_EXT_KEYLEN)) { 85 printk(KERN_ERR "hfs: invalid extent max_key_len %d\n", 86 tree->max_key_len); 87 goto fail_page; 88 } 89 if ((id == HFS_CAT_CNID) && (tree->max_key_len != HFS_MAX_CAT_KEYLEN)) { 90 printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n", 91 tree->max_key_len); 92 goto fail_page; 93 } 94 95 tree->node_size_shift = ffs(size) - 1; 96 tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 97 98 kunmap(page); 99 page_cache_release(page); 100 return tree; 101 102 fail_page: 103 page_cache_release(page); 104 free_inode: 105 tree->inode->i_mapping->a_ops = &hfs_aops; 106 iput(tree->inode); 107 free_tree: 108 kfree(tree); 109 return NULL; 110 } 111 112 /* Release resources used by a btree */ 113 void hfs_btree_close(struct hfs_btree *tree) 114 { 115 struct hfs_bnode *node; 116 int i; 117 118 if (!tree) 119 return; 120 121 for (i = 0; i < NODE_HASH_SIZE; i++) { 122 while ((node = tree->node_hash[i])) { 123 tree->node_hash[i] = node->next_hash; 124 if (atomic_read(&node->refcnt)) 125 printk(KERN_ERR "hfs: node %d:%d still has %d user(s)!\n", 126 node->tree->cnid, node->this, atomic_read(&node->refcnt)); 127 hfs_bnode_free(node); 128 tree->node_hash_cnt--; 129 } 130 } 131 iput(tree->inode); 132 kfree(tree); 133 } 134 135 void hfs_btree_write(struct hfs_btree *tree) 136 { 137 struct hfs_btree_header_rec *head; 138 struct hfs_bnode *node; 139 struct page *page; 140 141 node = hfs_bnode_find(tree, 0); 142 if (IS_ERR(node)) 143 /* panic? */ 144 return; 145 /* Load the header */ 146 page = node->page[0]; 147 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 148 149 head->root = cpu_to_be32(tree->root); 150 head->leaf_count = cpu_to_be32(tree->leaf_count); 151 head->leaf_head = cpu_to_be32(tree->leaf_head); 152 head->leaf_tail = cpu_to_be32(tree->leaf_tail); 153 head->node_count = cpu_to_be32(tree->node_count); 154 head->free_nodes = cpu_to_be32(tree->free_nodes); 155 head->attributes = cpu_to_be32(tree->attributes); 156 head->depth = cpu_to_be16(tree->depth); 157 158 kunmap(page); 159 set_page_dirty(page); 160 hfs_bnode_put(node); 161 } 162 163 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) 164 { 165 struct hfs_btree *tree = prev->tree; 166 struct hfs_bnode *node; 167 struct hfs_bnode_desc desc; 168 __be32 cnid; 169 170 node = hfs_bnode_create(tree, idx); 171 if (IS_ERR(node)) 172 return node; 173 174 if (!tree->free_nodes) 175 panic("FIXME!!!"); 176 tree->free_nodes--; 177 prev->next = idx; 178 cnid = cpu_to_be32(idx); 179 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); 180 181 node->type = HFS_NODE_MAP; 182 node->num_recs = 1; 183 hfs_bnode_clear(node, 0, tree->node_size); 184 desc.next = 0; 185 desc.prev = 0; 186 desc.type = HFS_NODE_MAP; 187 desc.height = 0; 188 desc.num_recs = cpu_to_be16(1); 189 desc.reserved = 0; 190 hfs_bnode_write(node, &desc, 0, sizeof(desc)); 191 hfs_bnode_write_u16(node, 14, 0x8000); 192 hfs_bnode_write_u16(node, tree->node_size - 2, 14); 193 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); 194 195 return node; 196 } 197 198 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) 199 { 200 struct hfs_bnode *node, *next_node; 201 struct page **pagep; 202 u32 nidx, idx; 203 u16 off, len; 204 u8 *data, byte, m; 205 int i; 206 207 while (!tree->free_nodes) { 208 struct inode *inode = tree->inode; 209 u32 count; 210 int res; 211 212 res = hfs_extend_file(inode); 213 if (res) 214 return ERR_PTR(res); 215 HFS_I(inode)->phys_size = inode->i_size = 216 (loff_t)HFS_I(inode)->alloc_blocks * 217 HFS_SB(tree->sb)->alloc_blksz; 218 HFS_I(inode)->fs_blocks = inode->i_size >> 219 tree->sb->s_blocksize_bits; 220 inode_set_bytes(inode, inode->i_size); 221 count = inode->i_size >> tree->node_size_shift; 222 tree->free_nodes = count - tree->node_count; 223 tree->node_count = count; 224 } 225 226 nidx = 0; 227 node = hfs_bnode_find(tree, nidx); 228 if (IS_ERR(node)) 229 return node; 230 len = hfs_brec_lenoff(node, 2, &off); 231 232 off += node->page_offset; 233 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 234 data = kmap(*pagep); 235 off &= ~PAGE_CACHE_MASK; 236 idx = 0; 237 238 for (;;) { 239 while (len) { 240 byte = data[off]; 241 if (byte != 0xff) { 242 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { 243 if (!(byte & m)) { 244 idx += i; 245 data[off] |= m; 246 set_page_dirty(*pagep); 247 kunmap(*pagep); 248 tree->free_nodes--; 249 mark_inode_dirty(tree->inode); 250 hfs_bnode_put(node); 251 return hfs_bnode_create(tree, idx); 252 } 253 } 254 } 255 if (++off >= PAGE_CACHE_SIZE) { 256 kunmap(*pagep); 257 data = kmap(*++pagep); 258 off = 0; 259 } 260 idx += 8; 261 len--; 262 } 263 kunmap(*pagep); 264 nidx = node->next; 265 if (!nidx) { 266 printk(KERN_DEBUG "hfs: create new bmap node...\n"); 267 next_node = hfs_bmap_new_bmap(node, idx); 268 } else 269 next_node = hfs_bnode_find(tree, nidx); 270 hfs_bnode_put(node); 271 if (IS_ERR(next_node)) 272 return next_node; 273 node = next_node; 274 275 len = hfs_brec_lenoff(node, 0, &off); 276 off += node->page_offset; 277 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 278 data = kmap(*pagep); 279 off &= ~PAGE_CACHE_MASK; 280 } 281 } 282 283 void hfs_bmap_free(struct hfs_bnode *node) 284 { 285 struct hfs_btree *tree; 286 struct page *page; 287 u16 off, len; 288 u32 nidx; 289 u8 *data, byte, m; 290 291 dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); 292 tree = node->tree; 293 nidx = node->this; 294 node = hfs_bnode_find(tree, 0); 295 if (IS_ERR(node)) 296 return; 297 len = hfs_brec_lenoff(node, 2, &off); 298 while (nidx >= len * 8) { 299 u32 i; 300 301 nidx -= len * 8; 302 i = node->next; 303 hfs_bnode_put(node); 304 if (!i) { 305 /* panic */; 306 printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this); 307 return; 308 } 309 node = hfs_bnode_find(tree, i); 310 if (IS_ERR(node)) 311 return; 312 if (node->type != HFS_NODE_MAP) { 313 /* panic */; 314 printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type); 315 hfs_bnode_put(node); 316 return; 317 } 318 len = hfs_brec_lenoff(node, 0, &off); 319 } 320 off += node->page_offset + nidx / 8; 321 page = node->page[off >> PAGE_CACHE_SHIFT]; 322 data = kmap(page); 323 off &= ~PAGE_CACHE_MASK; 324 m = 1 << (~nidx & 7); 325 byte = data[off]; 326 if (!(byte & m)) { 327 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type); 328 kunmap(page); 329 hfs_bnode_put(node); 330 return; 331 } 332 data[off] = byte & ~m; 333 set_page_dirty(page); 334 kunmap(page); 335 hfs_bnode_put(node); 336 tree->free_nodes++; 337 mark_inode_dirty(tree->inode); 338 } 339