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) + sizeof(struct hfs_bnode_desc));
  55         tree->root = be32_to_cpu(head->root);
  56         tree->leaf_count = be32_to_cpu(head->leaf_count);
  57         tree->leaf_head = be32_to_cpu(head->leaf_head);
  58         tree->leaf_tail = be32_to_cpu(head->leaf_tail);
  59         tree->node_count = be32_to_cpu(head->node_count);
  60         tree->free_nodes = be32_to_cpu(head->free_nodes);
  61         tree->attributes = be32_to_cpu(head->attributes);
  62         tree->node_size = be16_to_cpu(head->node_size);
  63         tree->max_key_len = be16_to_cpu(head->max_key_len);
  64         tree->depth = be16_to_cpu(head->depth);
  65
  66         /* Verify the tree and set the correct compare function */
  67         switch (id) {
  68         case HFSPLUS_EXT_CNID:
  69                 if (tree->max_key_len != HFSPLUS_EXT_KEYLEN - sizeof(u16)) {
  70                         printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
  71                                 tree->max_key_len);
  72                         goto fail_page;
  73                 }
  74                 if (tree->attributes & HFS_TREE_VARIDXKEYS) {
  75                         printk(KERN_ERR "hfs: invalid extent btree flag\n");
  76                         goto fail_page;
  77                 }
  78
  79                 tree->keycmp = hfsplus_ext_cmp_key;
  80                 break;
  81         case HFSPLUS_CAT_CNID:
  82                 if (tree->max_key_len != HFSPLUS_CAT_KEYLEN - sizeof(u16)) {
  83                         printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
  84                                 tree->max_key_len);
  85                         goto fail_page;
  86                 }
  87                 if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
  88                         printk(KERN_ERR "hfs: invalid catalog btree flag\n");
  89                         goto fail_page;
  90                 }
  91
  92                 if (test_bit(HFSPLUS_SB_HFSX, &HFSPLUS_SB(sb)->flags) &&
  93                     (head->key_type == HFSPLUS_KEY_BINARY))
  94                         tree->keycmp = hfsplus_cat_bin_cmp_key;
  95                 else {
  96                         tree->keycmp = hfsplus_cat_case_cmp_key;
  97                         set_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
  98                 }
  99                 break;
 100         default:
 101                 printk(KERN_ERR "hfs: unknown B*Tree requested\n");
 102                 goto fail_page;
 103         }
 104
 105         if (!(tree->attributes & HFS_TREE_BIGKEYS)) {
 106                 printk(KERN_ERR "hfs: invalid btree flag\n");
 107                 goto fail_page;
 108         }
 109
 110         size = tree->node_size;
 111         if (!is_power_of_2(size))
 112                 goto fail_page;
 113         if (!tree->node_count)
 114                 goto fail_page;
 115
 116         tree->node_size_shift = ffs(size) - 1;
 117
 118         tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 119
 120         kunmap(page);
 121         page_cache_release(page);
 122         return tree;
 123
 124  fail_page:
 125         page_cache_release(page);
 126  free_inode:
 127         tree->inode->i_mapping->a_ops = &hfsplus_aops;
 128         iput(tree->inode);
 129  free_tree:
 130         kfree(tree);
 131         return NULL;
 132 }
 133
 134 /* Release resources used by a btree */
 135 void hfs_btree_close(struct hfs_btree *tree)
 136 {
 137         struct hfs_bnode *node;
 138         int i;
 139
 140         if (!tree)
 141                 return;
 142
 143         for (i = 0; i < NODE_HASH_SIZE; i++) {
 144                 while ((node = tree->node_hash[i])) {
 145                         tree->node_hash[i] = node->next_hash;
 146                         if (atomic_read(&node->refcnt))
 147                                 printk(KERN_CRIT "hfs: node %d:%d still has %d user(s)!\n",
 148                                         node->tree->cnid, node->this, atomic_read(&node->refcnt));
 149                         hfs_bnode_free(node);
 150                         tree->node_hash_cnt--;
 151                 }
 152         }
 153         iput(tree->inode);
 154         kfree(tree);
 155 }
 156
 157 void hfs_btree_write(struct hfs_btree *tree)
 158 {
 159         struct hfs_btree_header_rec *head;
 160         struct hfs_bnode *node;
 161         struct page *page;
 162
 163         node = hfs_bnode_find(tree, 0);
 164         if (IS_ERR(node))
 165                 /* panic? */
 166                 return;
 167         /* Load the header */
 168         page = node->page[0];
 169         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
 170
 171         head->root = cpu_to_be32(tree->root);
 172         head->leaf_count = cpu_to_be32(tree->leaf_count);
 173         head->leaf_head = cpu_to_be32(tree->leaf_head);
 174         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
 175         head->node_count = cpu_to_be32(tree->node_count);
 176         head->free_nodes = cpu_to_be32(tree->free_nodes);
 177         head->attributes = cpu_to_be32(tree->attributes);
 178         head->depth = cpu_to_be16(tree->depth);
 179
 180         kunmap(page);
 181         set_page_dirty(page);
 182         hfs_bnode_put(node);
 183 }
 184
 185 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 186 {
 187         struct hfs_btree *tree = prev->tree;
 188         struct hfs_bnode *node;
 189         struct hfs_bnode_desc desc;
 190         __be32 cnid;
 191
 192         node = hfs_bnode_create(tree, idx);
 193         if (IS_ERR(node))
 194                 return node;
 195
 196         tree->free_nodes--;
 197         prev->next = idx;
 198         cnid = cpu_to_be32(idx);
 199         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 200
 201         node->type = HFS_NODE_MAP;
 202         node->num_recs = 1;
 203         hfs_bnode_clear(node, 0, tree->node_size);
 204         desc.next = 0;
 205         desc.prev = 0;
 206         desc.type = HFS_NODE_MAP;
 207         desc.height = 0;
 208         desc.num_recs = cpu_to_be16(1);
 209         desc.reserved = 0;
 210         hfs_bnode_write(node, &desc, 0, sizeof(desc));
 211         hfs_bnode_write_u16(node, 14, 0x8000);
 212         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
 213         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
 214
 215         return node;
 216 }
 217
 218 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 219 {
 220         struct hfs_bnode *node, *next_node;
 221         struct page **pagep;
 222         u32 nidx, idx;
 223         unsigned off;
 224         u16 off16;
 225         u16 len;
 226         u8 *data, byte, m;
 227         int i;
 228
 229         while (!tree->free_nodes) {
 230                 struct inode *inode = tree->inode;
 231                 struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 232                 u32 count;
 233                 int res;
 234
 235                 res = hfsplus_file_extend(inode);
 236                 if (res)
 237                         return ERR_PTR(res);
 238                 hip->phys_size = inode->i_size =
 239                         (loff_t)hip->alloc_blocks <<
 240                                 HFSPLUS_SB(tree->sb)->alloc_blksz_shift;
 241                 hip->fs_blocks =
 242                         hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift;
 243                 inode_set_bytes(inode, inode->i_size);
 244                 count = inode->i_size >> tree->node_size_shift;
 245                 tree->free_nodes = count - tree->node_count;
 246                 tree->node_count = count;
 247         }
 248
 249         nidx = 0;
 250         node = hfs_bnode_find(tree, nidx);
 251         if (IS_ERR(node))
 252                 return node;
 253         len = hfs_brec_lenoff(node, 2, &off16);
 254         off = off16;
 255
 256         off += node->page_offset;
 257         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 258         data = kmap(*pagep);
 259         off &= ~PAGE_CACHE_MASK;
 260         idx = 0;
 261
 262         for (;;) {
 263                 while (len) {
 264                         byte = data[off];
 265                         if (byte != 0xff) {
 266                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
 267                                         if (!(byte & m)) {
 268                                                 idx += i;
 269                                                 data[off] |= m;
 270                                                 set_page_dirty(*pagep);
 271                                                 kunmap(*pagep);
 272                                                 tree->free_nodes--;
 273                                                 mark_inode_dirty(tree->inode);
 274                                                 hfs_bnode_put(node);
 275                                                 return hfs_bnode_create(tree, idx);
 276                                         }
 277                                 }
 278                         }
 279                         if (++off >= PAGE_CACHE_SIZE) {
 280                                 kunmap(*pagep);
 281                                 data = kmap(*++pagep);
 282                                 off = 0;
 283                         }
 284                         idx += 8;
 285                         len--;
 286                 }
 287                 kunmap(*pagep);
 288                 nidx = node->next;
 289                 if (!nidx) {
 290                         printk(KERN_DEBUG "hfs: create new bmap node...\n");
 291                         next_node = hfs_bmap_new_bmap(node, idx);
 292                 } else
 293                         next_node = hfs_bnode_find(tree, nidx);
 294                 hfs_bnode_put(node);
 295                 if (IS_ERR(next_node))
 296                         return next_node;
 297                 node = next_node;
 298
 299                 len = hfs_brec_lenoff(node, 0, &off16);
 300                 off = off16;
 301                 off += node->page_offset;
 302                 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 303                 data = kmap(*pagep);
 304                 off &= ~PAGE_CACHE_MASK;
 305         }
 306 }
 307
 308 void hfs_bmap_free(struct hfs_bnode *node)
 309 {
 310         struct hfs_btree *tree;
 311         struct page *page;
 312         u16 off, len;
 313         u32 nidx;
 314         u8 *data, byte, m;
 315
 316         dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
 317         BUG_ON(!node->this);
 318         tree = node->tree;
 319         nidx = node->this;
 320         node = hfs_bnode_find(tree, 0);
 321         if (IS_ERR(node))
 322                 return;
 323         len = hfs_brec_lenoff(node, 2, &off);
 324         while (nidx >= len * 8) {
 325                 u32 i;
 326
 327                 nidx -= len * 8;
 328                 i = node->next;
 329                 hfs_bnode_put(node);
 330                 if (!i) {
 331                         /* panic */;
 332                         printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this);
 333                         return;
 334                 }
 335                 node = hfs_bnode_find(tree, i);
 336                 if (IS_ERR(node))
 337                         return;
 338                 if (node->type != HFS_NODE_MAP) {
 339                         /* panic */;
 340                         printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type);
 341                         hfs_bnode_put(node);
 342                         return;
 343                 }
 344                 len = hfs_brec_lenoff(node, 0, &off);
 345         }
 346         off += node->page_offset + nidx / 8;
 347         page = node->page[off >> PAGE_CACHE_SHIFT];
 348         data = kmap(page);
 349         off &= ~PAGE_CACHE_MASK;
 350         m = 1 << (~nidx & 7);
 351         byte = data[off];
 352         if (!(byte & m)) {
 353                 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type);
 354                 kunmap(page);
 355                 hfs_bnode_put(node);
 356                 return;
 357         }
 358         data[off] = byte & ~m;
 359         set_page_dirty(page);
 360         kunmap(page);
 361         hfs_bnode_put(node);
 362         tree->free_nodes++;
 363         mark_inode_dirty(tree->inode);
 364 }