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