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                 if (HFS_I(tree->inode)->alloc_blocks >
  49                                         HFS_I(tree->inode)->first_blocks) {
  50                         printk(KERN_ERR "hfs: invalid btree extent records\n");
  51                         unlock_new_inode(tree->inode);
  52                         goto free_inode;
  53                 }
  54
  55                 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
  56                 break;
  57         case HFS_CAT_CNID:
  58                 hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
  59                                     mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
  60
  61                 if (!HFS_I(tree->inode)->first_blocks) {
  62                         printk(KERN_ERR "hfs: invalid btree extent records "
  63                                                                 "(0 size).\n");
  64                         unlock_new_inode(tree->inode);
  65                         goto free_inode;
  66                 }
  67
  68                 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
  69                 break;
  70         default:
  71                 BUG();
  72         }
  73         }
  74         unlock_new_inode(tree->inode);
  75
  76         mapping = tree->inode->i_mapping;
  77         page = read_mapping_page(mapping, 0, NULL);
  78         if (IS_ERR(page))
  79                 goto free_inode;
  80
  81         /* Load the header */
  82         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
  83         tree->root = be32_to_cpu(head->root);
  84         tree->leaf_count = be32_to_cpu(head->leaf_count);
  85         tree->leaf_head = be32_to_cpu(head->leaf_head);
  86         tree->leaf_tail = be32_to_cpu(head->leaf_tail);
  87         tree->node_count = be32_to_cpu(head->node_count);
  88         tree->free_nodes = be32_to_cpu(head->free_nodes);
  89         tree->attributes = be32_to_cpu(head->attributes);
  90         tree->node_size = be16_to_cpu(head->node_size);
  91         tree->max_key_len = be16_to_cpu(head->max_key_len);
  92         tree->depth = be16_to_cpu(head->depth);
  93
  94         size = tree->node_size;
  95         if (!is_power_of_2(size))
  96                 goto fail_page;
  97         if (!tree->node_count)
  98                 goto fail_page;
  99         switch (id) {
 100         case HFS_EXT_CNID:
 101                 if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
 102                         printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
 103                                 tree->max_key_len);
 104                         goto fail_page;
 105                 }
 106                 break;
 107         case HFS_CAT_CNID:
 108                 if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
 109                         printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
 110                                 tree->max_key_len);
 111                         goto fail_page;
 112                 }
 113                 break;
 114         default:
 115                 BUG();
 116         }
 117
 118         tree->node_size_shift = ffs(size) - 1;
 119         tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 120
 121         kunmap(page);
 122         page_cache_release(page);
 123         return tree;
 124
 125 fail_page:
 126         page_cache_release(page);
 127 free_inode:
 128         tree->inode->i_mapping->a_ops = &hfs_aops;
 129         iput(tree->inode);
 130 free_tree:
 131         kfree(tree);
 132         return NULL;
 133 }
 134
 135 /* Release resources used by a btree */
 136 void hfs_btree_close(struct hfs_btree *tree)
 137 {
 138         struct hfs_bnode *node;
 139         int i;
 140
 141         if (!tree)
 142                 return;
 143
 144         for (i = 0; i < NODE_HASH_SIZE; i++) {
 145                 while ((node = tree->node_hash[i])) {
 146                         tree->node_hash[i] = node->next_hash;
 147                         if (atomic_read(&node->refcnt))
 148                                 printk(KERN_ERR "hfs: node %d:%d still has %d user(s)!\n",
 149                                         node->tree->cnid, node->this, atomic_read(&node->refcnt));
 150                         hfs_bnode_free(node);
 151                         tree->node_hash_cnt--;
 152                 }
 153         }
 154         iput(tree->inode);
 155         kfree(tree);
 156 }
 157
 158 void hfs_btree_write(struct hfs_btree *tree)
 159 {
 160         struct hfs_btree_header_rec *head;
 161         struct hfs_bnode *node;
 162         struct page *page;
 163
 164         node = hfs_bnode_find(tree, 0);
 165         if (IS_ERR(node))
 166                 /* panic? */
 167                 return;
 168         /* Load the header */
 169         page = node->page[0];
 170         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
 171
 172         head->root = cpu_to_be32(tree->root);
 173         head->leaf_count = cpu_to_be32(tree->leaf_count);
 174         head->leaf_head = cpu_to_be32(tree->leaf_head);
 175         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
 176         head->node_count = cpu_to_be32(tree->node_count);
 177         head->free_nodes = cpu_to_be32(tree->free_nodes);
 178         head->attributes = cpu_to_be32(tree->attributes);
 179         head->depth = cpu_to_be16(tree->depth);
 180
 181         kunmap(page);
 182         set_page_dirty(page);
 183         hfs_bnode_put(node);
 184 }
 185
 186 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 187 {
 188         struct hfs_btree *tree = prev->tree;
 189         struct hfs_bnode *node;
 190         struct hfs_bnode_desc desc;
 191         __be32 cnid;
 192
 193         node = hfs_bnode_create(tree, idx);
 194         if (IS_ERR(node))
 195                 return node;
 196
 197         if (!tree->free_nodes)
 198                 panic("FIXME!!!");
 199         tree->free_nodes--;
 200         prev->next = idx;
 201         cnid = cpu_to_be32(idx);
 202         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 203
 204         node->type = HFS_NODE_MAP;
 205         node->num_recs = 1;
 206         hfs_bnode_clear(node, 0, tree->node_size);
 207         desc.next = 0;
 208         desc.prev = 0;
 209         desc.type = HFS_NODE_MAP;
 210         desc.height = 0;
 211         desc.num_recs = cpu_to_be16(1);
 212         desc.reserved = 0;
 213         hfs_bnode_write(node, &desc, 0, sizeof(desc));
 214         hfs_bnode_write_u16(node, 14, 0x8000);
 215         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
 216         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
 217
 218         return node;
 219 }
 220
 221 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 222 {
 223         struct hfs_bnode *node, *next_node;
 224         struct page **pagep;
 225         u32 nidx, idx;
 226         unsigned off;
 227         u16 off16;
 228         u16 len;
 229         u8 *data, byte, m;
 230         int i;
 231
 232         while (!tree->free_nodes) {
 233                 struct inode *inode = tree->inode;
 234                 u32 count;
 235                 int res;
 236
 237                 res = hfs_extend_file(inode);
 238                 if (res)
 239                         return ERR_PTR(res);
 240                 HFS_I(inode)->phys_size = inode->i_size =
 241                                 (loff_t)HFS_I(inode)->alloc_blocks *
 242                                 HFS_SB(tree->sb)->alloc_blksz;
 243                 HFS_I(inode)->fs_blocks = inode->i_size >>
 244                                           tree->sb->s_blocksize_bits;
 245                 inode_set_bytes(inode, inode->i_size);
 246                 count = inode->i_size >> tree->node_size_shift;
 247                 tree->free_nodes = count - tree->node_count;
 248                 tree->node_count = count;
 249         }
 250
 251         nidx = 0;
 252         node = hfs_bnode_find(tree, nidx);
 253         if (IS_ERR(node))
 254                 return node;
 255         len = hfs_brec_lenoff(node, 2, &off16);
 256         off = off16;
 257
 258         off += node->page_offset;
 259         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 260         data = kmap(*pagep);
 261         off &= ~PAGE_CACHE_MASK;
 262         idx = 0;
 263
 264         for (;;) {
 265                 while (len) {
 266                         byte = data[off];
 267                         if (byte != 0xff) {
 268                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
 269                                         if (!(byte & m)) {
 270                                                 idx += i;
 271                                                 data[off] |= m;
 272                                                 set_page_dirty(*pagep);
 273                                                 kunmap(*pagep);
 274                                                 tree->free_nodes--;
 275                                                 mark_inode_dirty(tree->inode);
 276                                                 hfs_bnode_put(node);
 277                                                 return hfs_bnode_create(tree, idx);
 278                                         }
 279                                 }
 280                         }
 281                         if (++off >= PAGE_CACHE_SIZE) {
 282                                 kunmap(*pagep);
 283                                 data = kmap(*++pagep);
 284                                 off = 0;
 285                         }
 286                         idx += 8;
 287                         len--;
 288                 }
 289                 kunmap(*pagep);
 290                 nidx = node->next;
 291                 if (!nidx) {
 292                         printk(KERN_DEBUG "hfs: create new bmap node...\n");
 293                         next_node = hfs_bmap_new_bmap(node, idx);
 294                 } else
 295                         next_node = hfs_bnode_find(tree, nidx);
 296                 hfs_bnode_put(node);
 297                 if (IS_ERR(next_node))
 298                         return next_node;
 299                 node = next_node;
 300
 301                 len = hfs_brec_lenoff(node, 0, &off16);
 302                 off = off16;
 303                 off += node->page_offset;
 304                 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 305                 data = kmap(*pagep);
 306                 off &= ~PAGE_CACHE_MASK;
 307         }
 308 }
 309
 310 void hfs_bmap_free(struct hfs_bnode *node)
 311 {
 312         struct hfs_btree *tree;
 313         struct page *page;
 314         u16 off, len;
 315         u32 nidx;
 316         u8 *data, byte, m;
 317
 318         dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
 319         tree = node->tree;
 320         nidx = node->this;
 321         node = hfs_bnode_find(tree, 0);
 322         if (IS_ERR(node))
 323                 return;
 324         len = hfs_brec_lenoff(node, 2, &off);
 325         while (nidx >= len * 8) {
 326                 u32 i;
 327
 328                 nidx -= len * 8;
 329                 i = node->next;
 330                 hfs_bnode_put(node);
 331                 if (!i) {
 332                         /* panic */;
 333                         printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this);
 334                         return;
 335                 }
 336                 node = hfs_bnode_find(tree, i);
 337                 if (IS_ERR(node))
 338                         return;
 339                 if (node->type != HFS_NODE_MAP) {
 340                         /* panic */;
 341                         printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type);
 342                         hfs_bnode_put(node);
 343                         return;
 344                 }
 345                 len = hfs_brec_lenoff(node, 0, &off);
 346         }
 347         off += node->page_offset + nidx / 8;
 348         page = node->page[off >> PAGE_CACHE_SHIFT];
 349         data = kmap(page);
 350         off &= ~PAGE_CACHE_MASK;
 351         m = 1 << (~nidx & 7);
 352         byte = data[off];
 353         if (!(byte & m)) {
 354                 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type);
 355                 kunmap(page);
 356                 hfs_bnode_put(node);
 357                 return;
 358         }
 359         data[off] = byte & ~m;
 360         set_page_dirty(page);
 361         kunmap(page);
 362         hfs_bnode_put(node);
 363         tree->free_nodes++;
 364         mark_inode_dirty(tree->inode);
 365 }