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