fs/hfsplus/btree.c

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