Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | } |