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