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 switch (id) { 85 case HFS_EXT_CNID: 86 if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) { 87 printk(KERN_ERR "hfs: invalid extent max_key_len %d\n", 88 tree->max_key_len); 89 goto fail_page; 90 } 91 break; 92 case HFS_CAT_CNID: 93 if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) { 94 printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n", 95 tree->max_key_len); 96 goto fail_page; 97 } 98 break; 99 default: 100 BUG(); 101 } 102 103 tree->node_size_shift = ffs(size) - 1; 104 tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 105 106 kunmap(page); 107 page_cache_release(page); 108 return tree; 109 110 fail_page: 111 page_cache_release(page); 112 free_inode: 113 tree->inode->i_mapping->a_ops = &hfs_aops; 114 iput(tree->inode); 115 free_tree: 116 kfree(tree); 117 return NULL; 118 } 119 120 /* Release resources used by a btree */ 121 void hfs_btree_close(struct hfs_btree *tree) 122 { 123 struct hfs_bnode *node; 124 int i; 125 126 if (!tree) 127 return; 128 129 for (i = 0; i < NODE_HASH_SIZE; i++) { 130 while ((node = tree->node_hash[i])) { 131 tree->node_hash[i] = node->next_hash; 132 if (atomic_read(&node->refcnt)) 133 printk(KERN_ERR "hfs: node %d:%d still has %d user(s)!\n", 134 node->tree->cnid, node->this, atomic_read(&node->refcnt)); 135 hfs_bnode_free(node); 136 tree->node_hash_cnt--; 137 } 138 } 139 iput(tree->inode); 140 kfree(tree); 141 } 142 143 void hfs_btree_write(struct hfs_btree *tree) 144 { 145 struct hfs_btree_header_rec *head; 146 struct hfs_bnode *node; 147 struct page *page; 148 149 node = hfs_bnode_find(tree, 0); 150 if (IS_ERR(node)) 151 /* panic? */ 152 return; 153 /* Load the header */ 154 page = node->page[0]; 155 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 156 157 head->root = cpu_to_be32(tree->root); 158 head->leaf_count = cpu_to_be32(tree->leaf_count); 159 head->leaf_head = cpu_to_be32(tree->leaf_head); 160 head->leaf_tail = cpu_to_be32(tree->leaf_tail); 161 head->node_count = cpu_to_be32(tree->node_count); 162 head->free_nodes = cpu_to_be32(tree->free_nodes); 163 head->attributes = cpu_to_be32(tree->attributes); 164 head->depth = cpu_to_be16(tree->depth); 165 166 kunmap(page); 167 set_page_dirty(page); 168 hfs_bnode_put(node); 169 } 170 171 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) 172 { 173 struct hfs_btree *tree = prev->tree; 174 struct hfs_bnode *node; 175 struct hfs_bnode_desc desc; 176 __be32 cnid; 177 178 node = hfs_bnode_create(tree, idx); 179 if (IS_ERR(node)) 180 return node; 181 182 if (!tree->free_nodes) 183 panic("FIXME!!!"); 184 tree->free_nodes--; 185 prev->next = idx; 186 cnid = cpu_to_be32(idx); 187 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); 188 189 node->type = HFS_NODE_MAP; 190 node->num_recs = 1; 191 hfs_bnode_clear(node, 0, tree->node_size); 192 desc.next = 0; 193 desc.prev = 0; 194 desc.type = HFS_NODE_MAP; 195 desc.height = 0; 196 desc.num_recs = cpu_to_be16(1); 197 desc.reserved = 0; 198 hfs_bnode_write(node, &desc, 0, sizeof(desc)); 199 hfs_bnode_write_u16(node, 14, 0x8000); 200 hfs_bnode_write_u16(node, tree->node_size - 2, 14); 201 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); 202 203 return node; 204 } 205 206 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) 207 { 208 struct hfs_bnode *node, *next_node; 209 struct page **pagep; 210 u32 nidx, idx; 211 unsigned off; 212 u16 off16; 213 u16 len; 214 u8 *data, byte, m; 215 int i; 216 217 while (!tree->free_nodes) { 218 struct inode *inode = tree->inode; 219 u32 count; 220 int res; 221 222 res = hfs_extend_file(inode); 223 if (res) 224 return ERR_PTR(res); 225 HFS_I(inode)->phys_size = inode->i_size = 226 (loff_t)HFS_I(inode)->alloc_blocks * 227 HFS_SB(tree->sb)->alloc_blksz; 228 HFS_I(inode)->fs_blocks = inode->i_size >> 229 tree->sb->s_blocksize_bits; 230 inode_set_bytes(inode, inode->i_size); 231 count = inode->i_size >> tree->node_size_shift; 232 tree->free_nodes = count - tree->node_count; 233 tree->node_count = count; 234 } 235 236 nidx = 0; 237 node = hfs_bnode_find(tree, nidx); 238 if (IS_ERR(node)) 239 return node; 240 len = hfs_brec_lenoff(node, 2, &off16); 241 off = off16; 242 243 off += node->page_offset; 244 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 245 data = kmap(*pagep); 246 off &= ~PAGE_CACHE_MASK; 247 idx = 0; 248 249 for (;;) { 250 while (len) { 251 byte = data[off]; 252 if (byte != 0xff) { 253 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { 254 if (!(byte & m)) { 255 idx += i; 256 data[off] |= m; 257 set_page_dirty(*pagep); 258 kunmap(*pagep); 259 tree->free_nodes--; 260 mark_inode_dirty(tree->inode); 261 hfs_bnode_put(node); 262 return hfs_bnode_create(tree, idx); 263 } 264 } 265 } 266 if (++off >= PAGE_CACHE_SIZE) { 267 kunmap(*pagep); 268 data = kmap(*++pagep); 269 off = 0; 270 } 271 idx += 8; 272 len--; 273 } 274 kunmap(*pagep); 275 nidx = node->next; 276 if (!nidx) { 277 printk(KERN_DEBUG "hfs: create new bmap node...\n"); 278 next_node = hfs_bmap_new_bmap(node, idx); 279 } else 280 next_node = hfs_bnode_find(tree, nidx); 281 hfs_bnode_put(node); 282 if (IS_ERR(next_node)) 283 return next_node; 284 node = next_node; 285 286 len = hfs_brec_lenoff(node, 0, &off16); 287 off = off16; 288 off += node->page_offset; 289 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 290 data = kmap(*pagep); 291 off &= ~PAGE_CACHE_MASK; 292 } 293 } 294 295 void hfs_bmap_free(struct hfs_bnode *node) 296 { 297 struct hfs_btree *tree; 298 struct page *page; 299 u16 off, len; 300 u32 nidx; 301 u8 *data, byte, m; 302 303 dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); 304 tree = node->tree; 305 nidx = node->this; 306 node = hfs_bnode_find(tree, 0); 307 if (IS_ERR(node)) 308 return; 309 len = hfs_brec_lenoff(node, 2, &off); 310 while (nidx >= len * 8) { 311 u32 i; 312 313 nidx -= len * 8; 314 i = node->next; 315 hfs_bnode_put(node); 316 if (!i) { 317 /* panic */; 318 printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this); 319 return; 320 } 321 node = hfs_bnode_find(tree, i); 322 if (IS_ERR(node)) 323 return; 324 if (node->type != HFS_NODE_MAP) { 325 /* panic */; 326 printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type); 327 hfs_bnode_put(node); 328 return; 329 } 330 len = hfs_brec_lenoff(node, 0, &off); 331 } 332 off += node->page_offset + nidx / 8; 333 page = node->page[off >> PAGE_CACHE_SHIFT]; 334 data = kmap(page); 335 off &= ~PAGE_CACHE_MASK; 336 m = 1 << (~nidx & 7); 337 byte = data[off]; 338 if (!(byte & m)) { 339 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type); 340 kunmap(page); 341 hfs_bnode_put(node); 342 return; 343 } 344 data[off] = byte & ~m; 345 set_page_dirty(page); 346 kunmap(page); 347 hfs_bnode_put(node); 348 tree->free_nodes++; 349 mark_inode_dirty(tree->inode); 350 } 351