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