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/slab.h>
  13 #include <linux/log2.h>
  14
  15 #include "btree.h"
  16
  17 /* Get a reference to a B*Tree and do some initial checks */
  18 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp)
  19 {
  20         struct hfs_btree *tree;
  21         struct hfs_btree_header_rec *head;
  22         struct address_space *mapping;
  23         struct page *page;
  24         unsigned int size;
  25
  26         tree = kzalloc(sizeof(*tree), GFP_KERNEL);
  27         if (!tree)
  28                 return NULL;
  29
  30         mutex_init(&tree->tree_lock);
  31         spin_lock_init(&tree->hash_lock);
  32         /* Set the correct compare function */
  33         tree->sb = sb;
  34         tree->cnid = id;
  35         tree->keycmp = keycmp;
  36
  37         tree->inode = iget_locked(sb, id);
  38         if (!tree->inode)
  39                 goto free_tree;
  40         BUG_ON(!(tree->inode->i_state & I_NEW));
  41         {
  42         struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
  43         HFS_I(tree->inode)->flags = 0;
  44         mutex_init(&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                 if (HFS_I(tree->inode)->alloc_blocks >
  50                                         HFS_I(tree->inode)->first_blocks) {
  51                         pr_err("invalid btree extent records\n");
  52                         unlock_new_inode(tree->inode);
  53                         goto free_inode;
  54                 }
  55
  56                 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
  57                 break;
  58         case HFS_CAT_CNID:
  59                 hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
  60                                     mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
  61
  62                 if (!HFS_I(tree->inode)->first_blocks) {
  63                         pr_err("invalid btree extent records (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                         pr_err("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                         pr_err("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                                 pr_err("node %d:%d still has %d user(s)!\n",
 149                                        node->tree->cnid, node->this,
 150                                        atomic_read(&node->refcnt));
 151                         hfs_bnode_free(node);
 152                         tree->node_hash_cnt--;
 153                 }
 154         }
 155         iput(tree->inode);
 156         kfree(tree);
 157 }
 158
 159 void hfs_btree_write(struct hfs_btree *tree)
 160 {
 161         struct hfs_btree_header_rec *head;
 162         struct hfs_bnode *node;
 163         struct page *page;
 164
 165         node = hfs_bnode_find(tree, 0);
 166         if (IS_ERR(node))
 167                 /* panic? */
 168                 return;
 169         /* Load the header */
 170         page = node->page[0];
 171         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
 172
 173         head->root = cpu_to_be32(tree->root);
 174         head->leaf_count = cpu_to_be32(tree->leaf_count);
 175         head->leaf_head = cpu_to_be32(tree->leaf_head);
 176         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
 177         head->node_count = cpu_to_be32(tree->node_count);
 178         head->free_nodes = cpu_to_be32(tree->free_nodes);
 179         head->attributes = cpu_to_be32(tree->attributes);
 180         head->depth = cpu_to_be16(tree->depth);
 181
 182         kunmap(page);
 183         set_page_dirty(page);
 184         hfs_bnode_put(node);
 185 }
 186
 187 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 188 {
 189         struct hfs_btree *tree = prev->tree;
 190         struct hfs_bnode *node;
 191         struct hfs_bnode_desc desc;
 192         __be32 cnid;
 193
 194         node = hfs_bnode_create(tree, idx);
 195         if (IS_ERR(node))
 196                 return node;
 197
 198         if (!tree->free_nodes)
 199                 panic("FIXME!!!");
 200         tree->free_nodes--;
 201         prev->next = idx;
 202         cnid = cpu_to_be32(idx);
 203         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 204
 205         node->type = HFS_NODE_MAP;
 206         node->num_recs = 1;
 207         hfs_bnode_clear(node, 0, tree->node_size);
 208         desc.next = 0;
 209         desc.prev = 0;
 210         desc.type = HFS_NODE_MAP;
 211         desc.height = 0;
 212         desc.num_recs = cpu_to_be16(1);
 213         desc.reserved = 0;
 214         hfs_bnode_write(node, &desc, 0, sizeof(desc));
 215         hfs_bnode_write_u16(node, 14, 0x8000);
 216         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
 217         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
 218
 219         return node;
 220 }
 221
 222 /* Make sure @tree has enough space for the @rsvd_nodes */
 223 int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes)
 224 {
 225         struct inode *inode = tree->inode;
 226         u32 count;
 227         int res;
 228
 229         while (tree->free_nodes < rsvd_nodes) {
 230                 res = hfs_extend_file(inode);
 231                 if (res)
 232                         return res;
 233                 HFS_I(inode)->phys_size = inode->i_size =
 234                                 (loff_t)HFS_I(inode)->alloc_blocks *
 235                                 HFS_SB(tree->sb)->alloc_blksz;
 236                 HFS_I(inode)->fs_blocks = inode->i_size >>
 237                                           tree->sb->s_blocksize_bits;
 238                 inode_set_bytes(inode, inode->i_size);
 239                 count = inode->i_size >> tree->node_size_shift;
 240                 tree->free_nodes += count - tree->node_count;
 241                 tree->node_count = count;
 242         }
 243         return 0;
 244 }
 245
 246 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 247 {
 248         struct hfs_bnode *node, *next_node;
 249         struct page **pagep;
 250         u32 nidx, idx;
 251         unsigned off;
 252         u16 off16;
 253         u16 len;
 254         u8 *data, byte, m;
 255         int i, res;
 256
 257         res = hfs_bmap_reserve(tree, 1);
 258         if (res)
 259                 return ERR_PTR(res);
 260
 261         nidx = 0;
 262         node = hfs_bnode_find(tree, nidx);
 263         if (IS_ERR(node))
 264                 return node;
 265         len = hfs_brec_lenoff(node, 2, &off16);
 266         off = off16;
 267
 268         off += node->page_offset;
 269         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 270         data = kmap(*pagep);
 271         off &= ~PAGE_CACHE_MASK;
 272         idx = 0;
 273
 274         for (;;) {
 275                 while (len) {
 276                         byte = data[off];
 277                         if (byte != 0xff) {
 278                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
 279                                         if (!(byte & m)) {
 280                                                 idx += i;
 281                                                 data[off] |= m;
 282                                                 set_page_dirty(*pagep);
 283                                                 kunmap(*pagep);
 284                                                 tree->free_nodes--;
 285                                                 mark_inode_dirty(tree->inode);
 286                                                 hfs_bnode_put(node);
 287                                                 return hfs_bnode_create(tree, idx);
 288                                         }
 289                                 }
 290                         }
 291                         if (++off >= PAGE_CACHE_SIZE) {
 292                                 kunmap(*pagep);
 293                                 data = kmap(*++pagep);
 294                                 off = 0;
 295                         }
 296                         idx += 8;
 297                         len--;
 298                 }
 299                 kunmap(*pagep);
 300                 nidx = node->next;
 301                 if (!nidx) {
 302                         printk(KERN_DEBUG "create new bmap node...\n");
 303                         next_node = hfs_bmap_new_bmap(node, idx);
 304                 } else
 305                         next_node = hfs_bnode_find(tree, nidx);
 306                 hfs_bnode_put(node);
 307                 if (IS_ERR(next_node))
 308                         return next_node;
 309                 node = next_node;
 310
 311                 len = hfs_brec_lenoff(node, 0, &off16);
 312                 off = off16;
 313                 off += node->page_offset;
 314                 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 315                 data = kmap(*pagep);
 316                 off &= ~PAGE_CACHE_MASK;
 317         }
 318 }
 319
 320 void hfs_bmap_free(struct hfs_bnode *node)
 321 {
 322         struct hfs_btree *tree;
 323         struct page *page;
 324         u16 off, len;
 325         u32 nidx;
 326         u8 *data, byte, m;
 327
 328         hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this);
 329         tree = node->tree;
 330         nidx = node->this;
 331         node = hfs_bnode_find(tree, 0);
 332         if (IS_ERR(node))
 333                 return;
 334         len = hfs_brec_lenoff(node, 2, &off);
 335         while (nidx >= len * 8) {
 336                 u32 i;
 337
 338                 nidx -= len * 8;
 339                 i = node->next;
 340                 if (!i) {
 341                         /* panic */;
 342                         pr_crit("unable to free bnode %u. bmap not found!\n",
 343                                 node->this);
 344                         hfs_bnode_put(node);
 345                         return;
 346                 }
 347                 hfs_bnode_put(node);
 348                 node = hfs_bnode_find(tree, i);
 349                 if (IS_ERR(node))
 350                         return;
 351                 if (node->type != HFS_NODE_MAP) {
 352                         /* panic */;
 353                         pr_crit("invalid bmap found! (%u,%d)\n",
 354                                 node->this, node->type);
 355                         hfs_bnode_put(node);
 356                         return;
 357                 }
 358                 len = hfs_brec_lenoff(node, 0, &off);
 359         }
 360         off += node->page_offset + nidx / 8;
 361         page = node->page[off >> PAGE_CACHE_SHIFT];
 362         data = kmap(page);
 363         off &= ~PAGE_CACHE_MASK;
 364         m = 1 << (~nidx & 7);
 365         byte = data[off];
 366         if (!(byte & m)) {
 367                 pr_crit("trying to free free bnode %u(%d)\n",
 368                         node->this, node->type);
 369                 kunmap(page);
 370                 hfs_bnode_put(node);
 371                 return;
 372         }
 373         data[off] = byte & ~m;
 374         set_page_dirty(page);
 375         kunmap(page);
 376         hfs_bnode_put(node);
 377         tree->free_nodes++;
 378         mark_inode_dirty(tree->inode);
 379 }