fs/hfsplus/btree.c

   1 /*
   2  *  linux/fs/hfsplus/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/slab.h>
  12 #include <linux/pagemap.h>
  13
  14 #include "hfsplus_fs.h"
  15 #include "hfsplus_raw.h"
  16
  17
  18 /* Get a reference to a B*Tree and do some initial checks */
  19 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id)
  20 {
  21         struct hfs_btree *tree;
  22         struct hfs_btree_header_rec *head;
  23         struct address_space *mapping;
  24         struct page *page;
  25         unsigned int size;
  26
  27         tree = kmalloc(sizeof(*tree), GFP_KERNEL);
  28         if (!tree)
  29                 return NULL;
  30         memset(tree, 0, sizeof(*tree));
  31
  32         init_MUTEX(&tree->tree_lock);
  33         spin_lock_init(&tree->hash_lock);
  34         /* Set the correct compare function */
  35         tree->sb = sb;
  36         tree->cnid = id;
  37         if (id == HFSPLUS_EXT_CNID) {
  38                 tree->keycmp = hfsplus_ext_cmp_key;
  39         } else if (id == HFSPLUS_CAT_CNID) {
  40                 tree->keycmp = hfsplus_cat_cmp_key;
  41         } else {
  42                 printk("HFS+-fs: unknown B*Tree requested\n");
  43                 goto free_tree;
  44         }
  45         tree->inode = iget(sb, id);
  46         if (!tree->inode)
  47                 goto free_tree;
  48
  49         mapping = tree->inode->i_mapping;
  50         page = read_cache_page(mapping, 0, (filler_t *)mapping->a_ops->readpage, NULL);
  51         if (IS_ERR(page))
  52                 goto free_tree;
  53
  54         /* Load the header */
  55         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
  56         tree->root = be32_to_cpu(head->root);
  57         tree->leaf_count = be32_to_cpu(head->leaf_count);
  58         tree->leaf_head = be32_to_cpu(head->leaf_head);
  59         tree->leaf_tail = be32_to_cpu(head->leaf_tail);
  60         tree->node_count = be32_to_cpu(head->node_count);
  61         tree->free_nodes = be32_to_cpu(head->free_nodes);
  62         tree->attributes = be32_to_cpu(head->attributes);
  63         tree->node_size = be16_to_cpu(head->node_size);
  64         tree->max_key_len = be16_to_cpu(head->max_key_len);
  65         tree->depth = be16_to_cpu(head->depth);
  66
  67         size = tree->node_size;
  68         if (!size || size & (size - 1))
  69                 goto fail_page;
  70         if (!tree->node_count)
  71                 goto fail_page;
  72         tree->node_size_shift = ffs(size) - 1;
  73
  74         tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
  75
  76         kunmap(page);
  77         page_cache_release(page);
  78         return tree;
  79
  80  fail_page:
  81         tree->inode->i_mapping->a_ops = &hfsplus_aops;
  82         page_cache_release(page);
  83  free_tree:
  84         iput(tree->inode);
  85         kfree(tree);
  86         return NULL;
  87 }
  88
  89 /* Release resources used by a btree */
  90 void hfs_btree_close(struct hfs_btree *tree)
  91 {
  92         struct hfs_bnode *node;
  93         int i;
  94
  95         if (!tree)
  96                 return;
  97
  98         for (i = 0; i < NODE_HASH_SIZE; i++) {
  99                 while ((node = tree->node_hash[i])) {
 100                         tree->node_hash[i] = node->next_hash;
 101                         if (atomic_read(&node->refcnt))
 102                                 printk("HFS+: node %d:%d still has %d user(s)!\n",
 103                                         node->tree->cnid, node->this, atomic_read(&node->refcnt));
 104                         hfs_bnode_free(node);
 105                         tree->node_hash_cnt--;
 106                 }
 107         }
 108         iput(tree->inode);
 109         kfree(tree);
 110 }
 111
 112 void hfs_btree_write(struct hfs_btree *tree)
 113 {
 114         struct hfs_btree_header_rec *head;
 115         struct hfs_bnode *node;
 116         struct page *page;
 117
 118         node = hfs_bnode_find(tree, 0);
 119         if (IS_ERR(node))
 120                 /* panic? */
 121                 return;
 122         /* Load the header */
 123         page = node->page[0];
 124         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
 125
 126         head->root = cpu_to_be32(tree->root);
 127         head->leaf_count = cpu_to_be32(tree->leaf_count);
 128         head->leaf_head = cpu_to_be32(tree->leaf_head);
 129         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
 130         head->node_count = cpu_to_be32(tree->node_count);
 131         head->free_nodes = cpu_to_be32(tree->free_nodes);
 132         head->attributes = cpu_to_be32(tree->attributes);
 133         head->depth = cpu_to_be16(tree->depth);
 134
 135         kunmap(page);
 136         set_page_dirty(page);
 137         hfs_bnode_put(node);
 138 }
 139
 140 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 141 {
 142         struct hfs_btree *tree = prev->tree;
 143         struct hfs_bnode *node;
 144         struct hfs_bnode_desc desc;
 145         __be32 cnid;
 146
 147         node = hfs_bnode_create(tree, idx);
 148         if (IS_ERR(node))
 149                 return node;
 150
 151         tree->free_nodes--;
 152         prev->next = idx;
 153         cnid = cpu_to_be32(idx);
 154         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 155
 156         node->type = HFS_NODE_MAP;
 157         node->num_recs = 1;
 158         hfs_bnode_clear(node, 0, tree->node_size);
 159         desc.next = 0;
 160         desc.prev = 0;
 161         desc.type = HFS_NODE_MAP;
 162         desc.height = 0;
 163         desc.num_recs = cpu_to_be16(1);
 164         desc.reserved = 0;
 165         hfs_bnode_write(node, &desc, 0, sizeof(desc));
 166         hfs_bnode_write_u16(node, 14, 0x8000);
 167         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
 168         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
 169
 170         return node;
 171 }
 172
 173 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 174 {
 175         struct hfs_bnode *node, *next_node;
 176         struct page **pagep;
 177         u32 nidx, idx;
 178         u16 off, len;
 179         u8 *data, byte, m;
 180         int i;
 181
 182         while (!tree->free_nodes) {
 183                 struct inode *inode = tree->inode;
 184                 u32 count;
 185                 int res;
 186
 187                 res = hfsplus_file_extend(inode);
 188                 if (res)
 189                         return ERR_PTR(res);
 190                 HFSPLUS_I(inode).phys_size = inode->i_size =
 191                                 (loff_t)HFSPLUS_I(inode).alloc_blocks <<
 192                                 HFSPLUS_SB(tree->sb).alloc_blksz_shift;
 193                 HFSPLUS_I(inode).fs_blocks = HFSPLUS_I(inode).alloc_blocks <<
 194                                              HFSPLUS_SB(tree->sb).fs_shift;
 195                 inode_set_bytes(inode, inode->i_size);
 196                 count = inode->i_size >> tree->node_size_shift;
 197                 tree->free_nodes = count - tree->node_count;
 198                 tree->node_count = count;
 199         }
 200
 201         nidx = 0;
 202         node = hfs_bnode_find(tree, nidx);
 203         if (IS_ERR(node))
 204                 return node;
 205         len = hfs_brec_lenoff(node, 2, &off);
 206
 207         off += node->page_offset;
 208         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 209         data = kmap(*pagep);
 210         off &= ~PAGE_CACHE_MASK;
 211         idx = 0;
 212
 213         for (;;) {
 214                 while (len) {
 215                         byte = data[off];
 216                         if (byte != 0xff) {
 217                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
 218                                         if (!(byte & m)) {
 219                                                 idx += i;
 220                                                 data[off] |= m;
 221                                                 set_page_dirty(*pagep);
 222                                                 kunmap(*pagep);
 223                                                 tree->free_nodes--;
 224                                                 mark_inode_dirty(tree->inode);
 225                                                 hfs_bnode_put(node);
 226                                                 if (!idx) {
 227                                                         printk("unexpected idx %u (%u)\n", idx, node->this);
 228                                                         BUG();
 229                                                 }
 230                                                 return hfs_bnode_create(tree, idx);
 231                                         }
 232                                 }
 233                         }
 234                         if (++off >= PAGE_CACHE_SIZE) {
 235                                 kunmap(*pagep);
 236                                 data = kmap(*++pagep);
 237                                 off = 0;
 238                         }
 239                         idx += 8;
 240                         len--;
 241                 }
 242                 kunmap(*pagep);
 243                 nidx = node->next;
 244                 if (!nidx) {
 245                         printk("create new bmap node...\n");
 246                         next_node = hfs_bmap_new_bmap(node, idx);
 247                 } else
 248                         next_node = hfs_bnode_find(tree, nidx);
 249                 hfs_bnode_put(node);
 250                 if (IS_ERR(next_node))
 251                         return next_node;
 252                 node = next_node;
 253
 254                 len = hfs_brec_lenoff(node, 0, &off);
 255                 off += node->page_offset;
 256                 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 257                 data = kmap(*pagep);
 258                 off &= ~PAGE_CACHE_MASK;
 259         }
 260 }
 261
 262 void hfs_bmap_free(struct hfs_bnode *node)
 263 {
 264         struct hfs_btree *tree;
 265         struct page *page;
 266         u16 off, len;
 267         u32 nidx;
 268         u8 *data, byte, m;
 269
 270         dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
 271         if (!node->this)
 272                 BUG();
 273         tree = node->tree;
 274         nidx = node->this;
 275         node = hfs_bnode_find(tree, 0);
 276         if (IS_ERR(node))
 277                 return;
 278         len = hfs_brec_lenoff(node, 2, &off);
 279         while (nidx >= len * 8) {
 280                 u32 i;
 281
 282                 nidx -= len * 8;
 283                 i = node->next;
 284                 hfs_bnode_put(node);
 285                 if (!i) {
 286                         /* panic */;
 287                         printk("HFS: unable to free bnode %u. bmap not found!\n", node->this);
 288                         return;
 289                 }
 290                 node = hfs_bnode_find(tree, i);
 291                 if (IS_ERR(node))
 292                         return;
 293                 if (node->type != HFS_NODE_MAP) {
 294                         /* panic */;
 295                         printk("HFS: invalid bmap found! (%u,%d)\n", node->this, node->type);
 296                         hfs_bnode_put(node);
 297                         return;
 298                 }
 299                 len = hfs_brec_lenoff(node, 0, &off);
 300         }
 301         off += node->page_offset + nidx / 8;
 302         page = node->page[off >> PAGE_CACHE_SHIFT];
 303         data = kmap(page);
 304         off &= ~PAGE_CACHE_MASK;
 305         m = 1 << (~nidx & 7);
 306         byte = data[off];
 307         if (!(byte & m)) {
 308                 printk("HFS: trying to free free bnode %u(%d)\n", node->this, node->type);
 309                 kunmap(page);
 310                 hfs_bnode_put(node);
 311                 return;
 312         }
 313         data[off] = byte & ~m;
 314         set_page_dirty(page);
 315         kunmap(page);
 316         hfs_bnode_put(node);
 317         tree->free_nodes++;
 318         mark_inode_dirty(tree->inode);
 319 }