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 #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 */
  20 struct 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 inode *inode;
  26         struct page *page;
  27         unsigned int size;
  28
  29         tree = kzalloc(sizeof(*tree), GFP_KERNEL);
  30         if (!tree)
  31                 return NULL;
  32
  33         mutex_init(&tree->tree_lock);
  34         spin_lock_init(&tree->hash_lock);
  35         tree->sb = sb;
  36         tree->cnid = id;
  37         inode = hfsplus_iget(sb, id);
  38         if (IS_ERR(inode))
  39                 goto free_tree;
  40         tree->inode = inode;
  41
  42         if (!HFSPLUS_I(tree->inode)->first_blocks) {
  43                 printk(KERN_ERR
  44                        "hfs: invalid btree extent records (0 size).\n");
  45                 goto free_inode;
  46         }
  47
  48         mapping = tree->inode->i_mapping;
  49         page = read_mapping_page(mapping, 0, NULL);
  50         if (IS_ERR(page))
  51                 goto free_inode;
  52
  53         /* Load the header */
  54         head = (struct hfs_btree_header_rec *)(kmap(page) +
  55                 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         /* Verify the tree and set the correct compare function */
  68         switch (id) {
  69         case HFSPLUS_EXT_CNID:
  70                 if (tree->max_key_len != HFSPLUS_EXT_KEYLEN - sizeof(u16)) {
  71                         printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
  72                                 tree->max_key_len);
  73                         goto fail_page;
  74                 }
  75                 if (tree->attributes & HFS_TREE_VARIDXKEYS) {
  76                         printk(KERN_ERR "hfs: invalid extent btree flag\n");
  77                         goto fail_page;
  78                 }
  79
  80                 tree->keycmp = hfsplus_ext_cmp_key;
  81                 break;
  82         case HFSPLUS_CAT_CNID:
  83                 if (tree->max_key_len != HFSPLUS_CAT_KEYLEN - sizeof(u16)) {
  84                         printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
  85                                 tree->max_key_len);
  86                         goto fail_page;
  87                 }
  88                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
  89                         printk(KERN_ERR "hfs: invalid catalog btree flag\n");
  90                         goto fail_page;
  91                 }
  92
  93                 if (test_bit(HFSPLUS_SB_HFSX, &HFSPLUS_SB(sb)->flags) &&
  94                     (head->key_type == HFSPLUS_KEY_BINARY))
  95                         tree->keycmp = hfsplus_cat_bin_cmp_key;
  96                 else {
  97                         tree->keycmp = hfsplus_cat_case_cmp_key;
  98                         set_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
  99                 }
 100                 break;
 101         case HFSPLUS_ATTR_CNID:
 102                 if (tree->max_key_len != HFSPLUS_ATTR_KEYLEN - sizeof(u16)) {
 103                         printk(KERN_ERR "hfs: invalid attributes max_key_len %d\n",
 104                                 tree->max_key_len);
 105                         goto fail_page;
 106                 }
 107                 tree->keycmp = hfsplus_attr_bin_cmp_key;
 108                 break;
 109         default:
 110                 printk(KERN_ERR "hfs: unknown B*Tree requested\n");
 111                 goto fail_page;
 112         }
 113
 114         if (!(tree->attributes & HFS_TREE_BIGKEYS)) {
 115                 printk(KERN_ERR "hfs: invalid btree flag\n");
 116                 goto fail_page;
 117         }
 118
 119         size = tree->node_size;
 120         if (!is_power_of_2(size))
 121                 goto fail_page;
 122         if (!tree->node_count)
 123                 goto fail_page;
 124
 125         tree->node_size_shift = ffs(size) - 1;
 126
 127         tree->pages_per_bnode =
 128                 (tree->node_size + PAGE_CACHE_SIZE - 1) >>
 129                 PAGE_CACHE_SHIFT;
 130
 131         kunmap(page);
 132         page_cache_release(page);
 133         return tree;
 134
 135  fail_page:
 136         page_cache_release(page);
 137  free_inode:
 138         tree->inode->i_mapping->a_ops = &hfsplus_aops;
 139         iput(tree->inode);
 140  free_tree:
 141         kfree(tree);
 142         return NULL;
 143 }
 144
 145 /* Release resources used by a btree */
 146 void hfs_btree_close(struct hfs_btree *tree)
 147 {
 148         struct hfs_bnode *node;
 149         int i;
 150
 151         if (!tree)
 152                 return;
 153
 154         for (i = 0; i < NODE_HASH_SIZE; i++) {
 155                 while ((node = tree->node_hash[i])) {
 156                         tree->node_hash[i] = node->next_hash;
 157                         if (atomic_read(&node->refcnt))
 158                                 printk(KERN_CRIT "hfs: node %d:%d "
 159                                                 "still has %d user(s)!\n",
 160                                         node->tree->cnid, node->this,
 161                                         atomic_read(&node->refcnt));
 162                         hfs_bnode_free(node);
 163                         tree->node_hash_cnt--;
 164                 }
 165         }
 166         iput(tree->inode);
 167         kfree(tree);
 168 }
 169
 170 void hfs_btree_write(struct hfs_btree *tree)
 171 {
 172         struct hfs_btree_header_rec *head;
 173         struct hfs_bnode *node;
 174         struct page *page;
 175
 176         node = hfs_bnode_find(tree, 0);
 177         if (IS_ERR(node))
 178                 /* panic? */
 179                 return;
 180         /* Load the header */
 181         page = node->page[0];
 182         head = (struct hfs_btree_header_rec *)(kmap(page) +
 183                 sizeof(struct hfs_bnode_desc));
 184
 185         head->root = cpu_to_be32(tree->root);
 186         head->leaf_count = cpu_to_be32(tree->leaf_count);
 187         head->leaf_head = cpu_to_be32(tree->leaf_head);
 188         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
 189         head->node_count = cpu_to_be32(tree->node_count);
 190         head->free_nodes = cpu_to_be32(tree->free_nodes);
 191         head->attributes = cpu_to_be32(tree->attributes);
 192         head->depth = cpu_to_be16(tree->depth);
 193
 194         kunmap(page);
 195         set_page_dirty(page);
 196         hfs_bnode_put(node);
 197 }
 198
 199 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 200 {
 201         struct hfs_btree *tree = prev->tree;
 202         struct hfs_bnode *node;
 203         struct hfs_bnode_desc desc;
 204         __be32 cnid;
 205
 206         node = hfs_bnode_create(tree, idx);
 207         if (IS_ERR(node))
 208                 return node;
 209
 210         tree->free_nodes--;
 211         prev->next = idx;
 212         cnid = cpu_to_be32(idx);
 213         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 214
 215         node->type = HFS_NODE_MAP;
 216         node->num_recs = 1;
 217         hfs_bnode_clear(node, 0, tree->node_size);
 218         desc.next = 0;
 219         desc.prev = 0;
 220         desc.type = HFS_NODE_MAP;
 221         desc.height = 0;
 222         desc.num_recs = cpu_to_be16(1);
 223         desc.reserved = 0;
 224         hfs_bnode_write(node, &desc, 0, sizeof(desc));
 225         hfs_bnode_write_u16(node, 14, 0x8000);
 226         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
 227         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
 228
 229         return node;
 230 }
 231
 232 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 233 {
 234         struct hfs_bnode *node, *next_node;
 235         struct page **pagep;
 236         u32 nidx, idx;
 237         unsigned off;
 238         u16 off16;
 239         u16 len;
 240         u8 *data, byte, m;
 241         int i;
 242
 243         while (!tree->free_nodes) {
 244                 struct inode *inode = tree->inode;
 245                 struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 246                 u32 count;
 247                 int res;
 248
 249                 res = hfsplus_file_extend(inode);
 250                 if (res)
 251                         return ERR_PTR(res);
 252                 hip->phys_size = inode->i_size =
 253                         (loff_t)hip->alloc_blocks <<
 254                                 HFSPLUS_SB(tree->sb)->alloc_blksz_shift;
 255                 hip->fs_blocks =
 256                         hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift;
 257                 inode_set_bytes(inode, inode->i_size);
 258                 count = inode->i_size >> tree->node_size_shift;
 259                 tree->free_nodes = count - tree->node_count;
 260                 tree->node_count = count;
 261         }
 262
 263         nidx = 0;
 264         node = hfs_bnode_find(tree, nidx);
 265         if (IS_ERR(node))
 266                 return node;
 267         len = hfs_brec_lenoff(node, 2, &off16);
 268         off = off16;
 269
 270         off += node->page_offset;
 271         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 272         data = kmap(*pagep);
 273         off &= ~PAGE_CACHE_MASK;
 274         idx = 0;
 275
 276         for (;;) {
 277                 while (len) {
 278                         byte = data[off];
 279                         if (byte != 0xff) {
 280                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
 281                                         if (!(byte & m)) {
 282                                                 idx += i;
 283                                                 data[off] |= m;
 284                                                 set_page_dirty(*pagep);
 285                                                 kunmap(*pagep);
 286                                                 tree->free_nodes--;
 287                                                 mark_inode_dirty(tree->inode);
 288                                                 hfs_bnode_put(node);
 289                                                 return hfs_bnode_create(tree,
 290                                                         idx);
 291                                         }
 292                                 }
 293                         }
 294                         if (++off >= PAGE_CACHE_SIZE) {
 295                                 kunmap(*pagep);
 296                                 data = kmap(*++pagep);
 297                                 off = 0;
 298                         }
 299                         idx += 8;
 300                         len--;
 301                 }
 302                 kunmap(*pagep);
 303                 nidx = node->next;
 304                 if (!nidx) {
 305                         dprint(DBG_BNODE_MOD, "hfs: create new bmap node.\n");
 306                         next_node = hfs_bmap_new_bmap(node, idx);
 307                 } else
 308                         next_node = hfs_bnode_find(tree, nidx);
 309                 hfs_bnode_put(node);
 310                 if (IS_ERR(next_node))
 311                         return next_node;
 312                 node = next_node;
 313
 314                 len = hfs_brec_lenoff(node, 0, &off16);
 315                 off = off16;
 316                 off += node->page_offset;
 317                 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 318                 data = kmap(*pagep);
 319                 off &= ~PAGE_CACHE_MASK;
 320         }
 321 }
 322
 323 void hfs_bmap_free(struct hfs_bnode *node)
 324 {
 325         struct hfs_btree *tree;
 326         struct page *page;
 327         u16 off, len;
 328         u32 nidx;
 329         u8 *data, byte, m;
 330
 331         dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
 332         BUG_ON(!node->this);
 333         tree = node->tree;
 334         nidx = node->this;
 335         node = hfs_bnode_find(tree, 0);
 336         if (IS_ERR(node))
 337                 return;
 338         len = hfs_brec_lenoff(node, 2, &off);
 339         while (nidx >= len * 8) {
 340                 u32 i;
 341
 342                 nidx -= len * 8;
 343                 i = node->next;
 344                 hfs_bnode_put(node);
 345                 if (!i) {
 346                         /* panic */;
 347                         printk(KERN_CRIT "hfs: unable to free bnode %u. "
 348                                         "bmap not found!\n",
 349                                 node->this);
 350                         return;
 351                 }
 352                 node = hfs_bnode_find(tree, i);
 353                 if (IS_ERR(node))
 354                         return;
 355                 if (node->type != HFS_NODE_MAP) {
 356                         /* panic */;
 357                         printk(KERN_CRIT "hfs: invalid bmap found! "
 358                                         "(%u,%d)\n",
 359                                 node->this, node->type);
 360                         hfs_bnode_put(node);
 361                         return;
 362                 }
 363                 len = hfs_brec_lenoff(node, 0, &off);
 364         }
 365         off += node->page_offset + nidx / 8;
 366         page = node->page[off >> PAGE_CACHE_SHIFT];
 367         data = kmap(page);
 368         off &= ~PAGE_CACHE_MASK;
 369         m = 1 << (~nidx & 7);
 370         byte = data[off];
 371         if (!(byte & m)) {
 372                 printk(KERN_CRIT "hfs: trying to free free bnode "
 373                                 "%u(%d)\n",
 374                         node->this, node->type);
 375                 kunmap(page);
 376                 hfs_bnode_put(node);
 377                 return;
 378         }
 379         data[off] = byte & ~m;
 380         set_page_dirty(page);
 381         kunmap(page);
 382         hfs_bnode_put(node);
 383         tree->free_nodes++;
 384         mark_inode_dirty(tree->inode);
 385 }