fs/hfs/btree.c

   1 /*
   2  *  linux/fs/hfs/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/pagemap.h>
  12 #include <linux/log2.h>
  13
  14 #include "btree.h"
  15
  16 /* Get a reference to a B*Tree and do some initial checks */
  17 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp)
  18 {
  19         struct hfs_btree *tree;
  20         struct hfs_btree_header_rec *head;
  21         struct address_space *mapping;
  22         struct page *page;
  23         unsigned int size;
  24
  25         tree = kzalloc(sizeof(*tree), GFP_KERNEL);
  26         if (!tree)
  27                 return NULL;
  28
  29         init_MUTEX(&tree->tree_lock);
  30         spin_lock_init(&tree->hash_lock);
  31         /* Set the correct compare function */
  32         tree->sb = sb;
  33         tree->cnid = id;
  34         tree->keycmp = keycmp;
  35
  36         tree->inode = iget_locked(sb, id);
  37         if (!tree->inode)
  38                 goto free_tree;
  39         BUG_ON(!(tree->inode->i_state & I_NEW));
  40         {
  41         struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
  42         HFS_I(tree->inode)->flags = 0;
  43         mutex_init(&HFS_I(tree->inode)->extents_lock);
  44         switch (id) {
  45         case HFS_EXT_CNID:
  46                 hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize,
  47                                     mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz));
  48                 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
  49                 break;
  50         case HFS_CAT_CNID:
  51                 hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
  52                                     mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
  53                 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
  54                 break;
  55         default:
  56                 BUG();
  57         }
  58         }
  59         unlock_new_inode(tree->inode);
  60
  61         if (!HFS_I(tree->inode)->first_blocks) {
  62                 printk(KERN_ERR "hfs: invalid btree extent records (0 size).\n");
  63                 goto free_inode;
  64         }
  65
  66         mapping = tree->inode->i_mapping;
  67         page = read_mapping_page(mapping, 0, NULL);
  68         if (IS_ERR(page))
  69                 goto free_inode;
  70
  71         /* Load the header */
  72         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
  73         tree->root = be32_to_cpu(head->root);
  74         tree->leaf_count = be32_to_cpu(head->leaf_count);
  75         tree->leaf_head = be32_to_cpu(head->leaf_head);
  76         tree->leaf_tail = be32_to_cpu(head->leaf_tail);
  77         tree->node_count = be32_to_cpu(head->node_count);
  78         tree->free_nodes = be32_to_cpu(head->free_nodes);
  79         tree->attributes = be32_to_cpu(head->attributes);
  80         tree->node_size = be16_to_cpu(head->node_size);
  81         tree->max_key_len = be16_to_cpu(head->max_key_len);
  82         tree->depth = be16_to_cpu(head->depth);
  83
  84         size = tree->node_size;
  85         if (!is_power_of_2(size))
  86                 goto fail_page;
  87         if (!tree->node_count)
  88                 goto fail_page;
  89         switch (id) {
  90         case HFS_EXT_CNID:
  91                 if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
  92                         printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
  93                                 tree->max_key_len);
  94                         goto fail_page;
  95                 }
  96                 break;
  97         case HFS_CAT_CNID:
  98                 if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
  99                         printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
 100                                 tree->max_key_len);
 101                         goto fail_page;
 102                 }
 103                 break;
 104         default:
 105                 BUG();
 106         }
 107
 108         tree->node_size_shift = ffs(size) - 1;
 109         tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 110
 111         kunmap(page);
 112         page_cache_release(page);
 113         return tree;
 114
 115 fail_page:
 116         page_cache_release(page);
 117 free_inode:
 118         tree->inode->i_mapping->a_ops = &hfs_aops;
 119         iput(tree->inode);
 120 free_tree:
 121         kfree(tree);
 122         return NULL;
 123 }
 124
 125 /* Release resources used by a btree */
 126 void hfs_btree_close(struct hfs_btree *tree)
 127 {
 128         struct hfs_bnode *node;
 129         int i;
 130
 131         if (!tree)
 132                 return;
 133
 134         for (i = 0; i < NODE_HASH_SIZE; i++) {
 135                 while ((node = tree->node_hash[i])) {
 136                         tree->node_hash[i] = node->next_hash;
 137                         if (atomic_read(&node->refcnt))
 138                                 printk(KERN_ERR "hfs: node %d:%d still has %d user(s)!\n",
 139                                         node->tree->cnid, node->this, atomic_read(&node->refcnt));
 140                         hfs_bnode_free(node);
 141                         tree->node_hash_cnt--;
 142                 }
 143         }
 144         iput(tree->inode);
 145         kfree(tree);
 146 }
 147
 148 void hfs_btree_write(struct hfs_btree *tree)
 149 {
 150         struct hfs_btree_header_rec *head;
 151         struct hfs_bnode *node;
 152         struct page *page;
 153
 154         node = hfs_bnode_find(tree, 0);
 155         if (IS_ERR(node))
 156                 /* panic? */
 157                 return;
 158         /* Load the header */
 159         page = node->page[0];
 160         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
 161
 162         head->root = cpu_to_be32(tree->root);
 163         head->leaf_count = cpu_to_be32(tree->leaf_count);
 164         head->leaf_head = cpu_to_be32(tree->leaf_head);
 165         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
 166         head->node_count = cpu_to_be32(tree->node_count);
 167         head->free_nodes = cpu_to_be32(tree->free_nodes);
 168         head->attributes = cpu_to_be32(tree->attributes);
 169         head->depth = cpu_to_be16(tree->depth);
 170
 171         kunmap(page);
 172         set_page_dirty(page);
 173         hfs_bnode_put(node);
 174 }
 175
 176 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 177 {
 178         struct hfs_btree *tree = prev->tree;
 179         struct hfs_bnode *node;
 180         struct hfs_bnode_desc desc;
 181         __be32 cnid;
 182
 183         node = hfs_bnode_create(tree, idx);
 184         if (IS_ERR(node))
 185                 return node;
 186
 187         if (!tree->free_nodes)
 188                 panic("FIXME!!!");
 189         tree->free_nodes--;
 190         prev->next = idx;
 191         cnid = cpu_to_be32(idx);
 192         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 193
 194         node->type = HFS_NODE_MAP;
 195         node->num_recs = 1;
 196         hfs_bnode_clear(node, 0, tree->node_size);
 197         desc.next = 0;
 198         desc.prev = 0;
 199         desc.type = HFS_NODE_MAP;
 200         desc.height = 0;
 201         desc.num_recs = cpu_to_be16(1);
 202         desc.reserved = 0;
 203         hfs_bnode_write(node, &desc, 0, sizeof(desc));
 204         hfs_bnode_write_u16(node, 14, 0x8000);
 205         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
 206         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
 207
 208         return node;
 209 }
 210
 211 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 212 {
 213         struct hfs_bnode *node, *next_node;
 214         struct page **pagep;
 215         u32 nidx, idx;
 216         unsigned off;
 217         u16 off16;
 218         u16 len;
 219         u8 *data, byte, m;
 220         int i;
 221
 222         while (!tree->free_nodes) {
 223                 struct inode *inode = tree->inode;
 224                 u32 count;
 225                 int res;
 226
 227                 res = hfs_extend_file(inode);
 228                 if (res)
 229                         return ERR_PTR(res);
 230                 HFS_I(inode)->phys_size = inode->i_size =
 231                                 (loff_t)HFS_I(inode)->alloc_blocks *
 232                                 HFS_SB(tree->sb)->alloc_blksz;
 233                 HFS_I(inode)->fs_blocks = inode->i_size >>
 234                                           tree->sb->s_blocksize_bits;
 235                 inode_set_bytes(inode, inode->i_size);
 236                 count = inode->i_size >> tree->node_size_shift;
 237                 tree->free_nodes = count - tree->node_count;
 238                 tree->node_count = count;
 239         }
 240
 241         nidx = 0;
 242         node = hfs_bnode_find(tree, nidx);
 243         if (IS_ERR(node))
 244                 return node;
 245         len = hfs_brec_lenoff(node, 2, &off16);
 246         off = off16;
 247
 248         off += node->page_offset;
 249         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 250         data = kmap(*pagep);
 251         off &= ~PAGE_CACHE_MASK;
 252         idx = 0;
 253
 254         for (;;) {
 255                 while (len) {
 256                         byte = data[off];
 257                         if (byte != 0xff) {
 258                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
 259                                         if (!(byte & m)) {
 260                                                 idx += i;
 261                                                 data[off] |= m;
 262                                                 set_page_dirty(*pagep);
 263                                                 kunmap(*pagep);
 264                                                 tree->free_nodes--;
 265                                                 mark_inode_dirty(tree->inode);
 266                                                 hfs_bnode_put(node);
 267                                                 return hfs_bnode_create(tree, idx);
 268                                         }
 269                                 }
 270                         }
 271                         if (++off >= PAGE_CACHE_SIZE) {
 272                                 kunmap(*pagep);
 273                                 data = kmap(*++pagep);
 274                                 off = 0;
 275                         }
 276                         idx += 8;
 277                         len--;
 278                 }
 279                 kunmap(*pagep);
 280                 nidx = node->next;
 281                 if (!nidx) {
 282                         printk(KERN_DEBUG "hfs: create new bmap node...\n");
 283                         next_node = hfs_bmap_new_bmap(node, idx);
 284                 } else
 285                         next_node = hfs_bnode_find(tree, nidx);
 286                 hfs_bnode_put(node);
 287                 if (IS_ERR(next_node))
 288                         return next_node;
 289                 node = next_node;
 290
 291                 len = hfs_brec_lenoff(node, 0, &off16);
 292                 off = off16;
 293                 off += node->page_offset;
 294                 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 295                 data = kmap(*pagep);
 296                 off &= ~PAGE_CACHE_MASK;
 297         }
 298 }
 299
 300 void hfs_bmap_free(struct hfs_bnode *node)
 301 {
 302         struct hfs_btree *tree;
 303         struct page *page;
 304         u16 off, len;
 305         u32 nidx;
 306         u8 *data, byte, m;
 307
 308         dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
 309         tree = node->tree;
 310         nidx = node->this;
 311         node = hfs_bnode_find(tree, 0);
 312         if (IS_ERR(node))
 313                 return;
 314         len = hfs_brec_lenoff(node, 2, &off);
 315         while (nidx >= len * 8) {
 316                 u32 i;
 317
 318                 nidx -= len * 8;
 319                 i = node->next;
 320                 hfs_bnode_put(node);
 321                 if (!i) {
 322                         /* panic */;
 323                         printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this);
 324                         return;
 325                 }
 326                 node = hfs_bnode_find(tree, i);
 327                 if (IS_ERR(node))
 328                         return;
 329                 if (node->type != HFS_NODE_MAP) {
 330                         /* panic */;
 331                         printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type);
 332                         hfs_bnode_put(node);
 333                         return;
 334                 }
 335                 len = hfs_brec_lenoff(node, 0, &off);
 336         }
 337         off += node->page_offset + nidx / 8;
 338         page = node->page[off >> PAGE_CACHE_SHIFT];
 339         data = kmap(page);
 340         off &= ~PAGE_CACHE_MASK;
 341         m = 1 << (~nidx & 7);
 342         byte = data[off];
 343         if (!(byte & m)) {
 344                 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type);
 345                 kunmap(page);
 346                 hfs_bnode_put(node);
 347                 return;
 348         }
 349         data[off] = byte & ~m;
 350         set_page_dirty(page);
 351         kunmap(page);
 352         hfs_bnode_put(node);
 353         tree->free_nodes++;
 354         mark_inode_dirty(tree->inode);
 355 }