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#include <linux/log2.h> 14 15#include "hfsplus_fs.h" 16#include "hfsplus_raw.h" 17 18 19/* Get a reference to a B*Tree and do some initial checks */ 20struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id) 21{ 22 struct hfs_btree *tree; 23 struct hfs_btree_header_rec *head; 24 struct address_space *mapping; 25 struct page *page; 26 unsigned int size; 27 28 tree = kzalloc(sizeof(*tree), GFP_KERNEL); 29 if (!tree) 30 return NULL; 31 32 init_MUTEX(&tree->tree_lock); 33 spin_lock_init(&tree->hash_lock); 34 tree->sb = sb; 35 tree->cnid = id; 36 tree->inode = iget(sb, id); 37 if (!tree->inode) 38 goto free_tree; 39 40 mapping = tree->inode->i_mapping; 41 page = read_mapping_page(mapping, 0, NULL); 42 if (IS_ERR(page)) 43 goto free_tree; 44 45 /* Load the header */ 46 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 47 tree->root = be32_to_cpu(head->root); 48 tree->leaf_count = be32_to_cpu(head->leaf_count); 49 tree->leaf_head = be32_to_cpu(head->leaf_head); 50 tree->leaf_tail = be32_to_cpu(head->leaf_tail); 51 tree->node_count = be32_to_cpu(head->node_count); 52 tree->free_nodes = be32_to_cpu(head->free_nodes); 53 tree->attributes = be32_to_cpu(head->attributes); 54 tree->node_size = be16_to_cpu(head->node_size); 55 tree->max_key_len = be16_to_cpu(head->max_key_len); 56 tree->depth = be16_to_cpu(head->depth); 57 58 /* Set the correct compare function */ 59 if (id == HFSPLUS_EXT_CNID) { 60 tree->keycmp = hfsplus_ext_cmp_key; 61 } else if (id == HFSPLUS_CAT_CNID) { 62 if ((HFSPLUS_SB(sb).flags & HFSPLUS_SB_HFSX) && 63 (head->key_type == HFSPLUS_KEY_BINARY)) 64 tree->keycmp = hfsplus_cat_bin_cmp_key; 65 else 66 tree->keycmp = hfsplus_cat_case_cmp_key; 67 } else { 68 printk(KERN_ERR "hfs: unknown B*Tree requested\n"); 69 goto fail_page; 70 } 71 72 size = tree->node_size; 73 if (!is_power_of_2(size)) 74 goto fail_page; 75 if (!tree->node_count) 76 goto fail_page; 77 tree->node_size_shift = ffs(size) - 1; 78 79 tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; 80 81 kunmap(page); 82 page_cache_release(page); 83 return tree; 84 85 fail_page: 86 tree->inode->i_mapping->a_ops = &hfsplus_aops; 87 page_cache_release(page); 88 free_tree: 89 iput(tree->inode); 90 kfree(tree); 91 return NULL; 92} 93 94/* Release resources used by a btree */ 95void hfs_btree_close(struct hfs_btree *tree) 96{ 97 struct hfs_bnode *node; 98 int i; 99 100 if (!tree) 101 return; 102 103 for (i = 0; i < NODE_HASH_SIZE; i++) { 104 while ((node = tree->node_hash[i])) { 105 tree->node_hash[i] = node->next_hash; 106 if (atomic_read(&node->refcnt)) 107 printk(KERN_CRIT "hfs: node %d:%d still has %d user(s)!\n", 108 node->tree->cnid, node->this, atomic_read(&node->refcnt)); 109 hfs_bnode_free(node); 110 tree->node_hash_cnt--; 111 } 112 } 113 iput(tree->inode); 114 kfree(tree); 115} 116 117void hfs_btree_write(struct hfs_btree *tree) 118{ 119 struct hfs_btree_header_rec *head; 120 struct hfs_bnode *node; 121 struct page *page; 122 123 node = hfs_bnode_find(tree, 0); 124 if (IS_ERR(node)) 125 /* panic? */ 126 return; 127 /* Load the header */ 128 page = node->page[0]; 129 head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); 130 131 head->root = cpu_to_be32(tree->root); 132 head->leaf_count = cpu_to_be32(tree->leaf_count); 133 head->leaf_head = cpu_to_be32(tree->leaf_head); 134 head->leaf_tail = cpu_to_be32(tree->leaf_tail); 135 head->node_count = cpu_to_be32(tree->node_count); 136 head->free_nodes = cpu_to_be32(tree->free_nodes); 137 head->attributes = cpu_to_be32(tree->attributes); 138 head->depth = cpu_to_be16(tree->depth); 139 140 kunmap(page); 141 set_page_dirty(page); 142 hfs_bnode_put(node); 143} 144 145static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) 146{ 147 struct hfs_btree *tree = prev->tree; 148 struct hfs_bnode *node; 149 struct hfs_bnode_desc desc; 150 __be32 cnid; 151 152 node = hfs_bnode_create(tree, idx); 153 if (IS_ERR(node)) 154 return node; 155 156 tree->free_nodes--; 157 prev->next = idx; 158 cnid = cpu_to_be32(idx); 159 hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); 160 161 node->type = HFS_NODE_MAP; 162 node->num_recs = 1; 163 hfs_bnode_clear(node, 0, tree->node_size); 164 desc.next = 0; 165 desc.prev = 0; 166 desc.type = HFS_NODE_MAP; 167 desc.height = 0; 168 desc.num_recs = cpu_to_be16(1); 169 desc.reserved = 0; 170 hfs_bnode_write(node, &desc, 0, sizeof(desc)); 171 hfs_bnode_write_u16(node, 14, 0x8000); 172 hfs_bnode_write_u16(node, tree->node_size - 2, 14); 173 hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); 174 175 return node; 176} 177 178struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) 179{ 180 struct hfs_bnode *node, *next_node; 181 struct page **pagep; 182 u32 nidx, idx; 183 u16 off, len; 184 u8 *data, byte, m; 185 int i; 186 187 while (!tree->free_nodes) { 188 struct inode *inode = tree->inode; 189 u32 count; 190 int res; 191 192 res = hfsplus_file_extend(inode); 193 if (res) 194 return ERR_PTR(res); 195 HFSPLUS_I(inode).phys_size = inode->i_size = 196 (loff_t)HFSPLUS_I(inode).alloc_blocks << 197 HFSPLUS_SB(tree->sb).alloc_blksz_shift; 198 HFSPLUS_I(inode).fs_blocks = HFSPLUS_I(inode).alloc_blocks << 199 HFSPLUS_SB(tree->sb).fs_shift; 200 inode_set_bytes(inode, inode->i_size); 201 /* Foxconn added start pling 05/31/2010 */ 202 /* Set the i_blocks field properly */ 203 inode->i_blocks = inode->i_size/512; 204 if (inode->i_size % 512) 205 inode->i_blocks++; 206 /* Foxconn added end pling 05/31/2010 */ 207 count = inode->i_size >> tree->node_size_shift; 208 tree->free_nodes = count - tree->node_count; 209 tree->node_count = count; 210 } 211 212 nidx = 0; 213 node = hfs_bnode_find(tree, nidx); 214 if (IS_ERR(node)) 215 return node; 216 len = hfs_brec_lenoff(node, 2, &off); 217 218 off += node->page_offset; 219 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 220 data = kmap(*pagep); 221 off &= ~PAGE_CACHE_MASK; 222 idx = 0; 223 224 for (;;) { 225 while (len) { 226 byte = data[off]; 227 if (byte != 0xff) { 228 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { 229 if (!(byte & m)) { 230 idx += i; 231 data[off] |= m; 232 set_page_dirty(*pagep); 233 kunmap(*pagep); 234 tree->free_nodes--; 235 mark_inode_dirty(tree->inode); 236 hfs_bnode_put(node); 237 return hfs_bnode_create(tree, idx); 238 } 239 } 240 } 241 if (++off >= PAGE_CACHE_SIZE) { 242 kunmap(*pagep); 243 data = kmap(*++pagep); 244 off = 0; 245 } 246 idx += 8; 247 len--; 248 } 249 kunmap(*pagep); 250 nidx = node->next; 251 if (!nidx) { 252 printk(KERN_DEBUG "hfs: create new bmap node...\n"); 253 next_node = hfs_bmap_new_bmap(node, idx); 254 } else 255 next_node = hfs_bnode_find(tree, nidx); 256 hfs_bnode_put(node); 257 if (IS_ERR(next_node)) 258 return next_node; 259 node = next_node; 260 261 len = hfs_brec_lenoff(node, 0, &off); 262 off += node->page_offset; 263 pagep = node->page + (off >> PAGE_CACHE_SHIFT); 264 data = kmap(*pagep); 265 off &= ~PAGE_CACHE_MASK; 266 } 267} 268 269void hfs_bmap_free(struct hfs_bnode *node) 270{ 271 struct hfs_btree *tree; 272 struct page *page; 273 u16 off, len; 274 u32 nidx; 275 u8 *data, byte, m; 276 277 dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); 278 BUG_ON(!node->this); 279 tree = node->tree; 280 nidx = node->this; 281 node = hfs_bnode_find(tree, 0); 282 if (IS_ERR(node)) 283 return; 284 len = hfs_brec_lenoff(node, 2, &off); 285 while (nidx >= len * 8) { 286 u32 i; 287 288 nidx -= len * 8; 289 i = node->next; 290 hfs_bnode_put(node); 291 if (!i) { 292 /* panic */; 293 printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this); 294 return; 295 } 296 node = hfs_bnode_find(tree, i); 297 if (IS_ERR(node)) 298 return; 299 if (node->type != HFS_NODE_MAP) { 300 /* panic */; 301 printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type); 302 hfs_bnode_put(node); 303 return; 304 } 305 len = hfs_brec_lenoff(node, 0, &off); 306 } 307 off += node->page_offset + nidx / 8; 308 page = node->page[off >> PAGE_CACHE_SHIFT]; 309 data = kmap(page); 310 off &= ~PAGE_CACHE_MASK; 311 m = 1 << (~nidx & 7); 312 byte = data[off]; 313 if (!(byte & m)) { 314 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type); 315 kunmap(page); 316 hfs_bnode_put(node); 317 return; 318 } 319 data[off] = byte & ~m; 320 set_page_dirty(page); 321 kunmap(page); 322 hfs_bnode_put(node); 323 tree->free_nodes++; 324 mark_inode_dirty(tree->inode); 325} 326