/* [<][>][^][v][top][bottom][index][help] */
DEFINITIONS
This source file includes following definitions.
- hfs_btree_open
- hfs_btree_close
- hfs_btree_write
- hfs_bmap_new_bmap
- hfs_bmap_alloc
- hfs_bmap_free
/*
* linux/fs/hfsplus/btree.c
*
* Copyright (C) 2001
* Brad Boyer (flar@allandria.com)
* (C) 2003 Ardis Technologies <roman@ardistech.com>
*
* Handle opening/closing btree
*/
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/log2.h>
#include "hfsplus_fs.h"
#include "hfsplus_raw.h"
/* Get a reference to a B*Tree and do some initial checks */
struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id)
{
struct hfs_btree *tree;
struct hfs_btree_header_rec *head;
struct address_space *mapping;
struct inode *inode;
struct page *page;
unsigned int size;
tree = kzalloc(sizeof(*tree), GFP_KERNEL);
if (!tree)
return NULL;
init_MUTEX(&tree->tree_lock);
spin_lock_init(&tree->hash_lock);
tree->sb = sb;
tree->cnid = id;
inode = hfsplus_iget(sb, id);
if (IS_ERR(inode))
goto free_tree;
tree->inode = inode;
mapping = tree->inode->i_mapping;
page = read_mapping_page(mapping, 0, NULL);
if (IS_ERR(page))
goto free_tree;
/* Load the header */
head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
tree->root = be32_to_cpu(head->root);
tree->leaf_count = be32_to_cpu(head->leaf_count);
tree->leaf_head = be32_to_cpu(head->leaf_head);
tree->leaf_tail = be32_to_cpu(head->leaf_tail);
tree->node_count = be32_to_cpu(head->node_count);
tree->free_nodes = be32_to_cpu(head->free_nodes);
tree->attributes = be32_to_cpu(head->attributes);
tree->node_size = be16_to_cpu(head->node_size);
tree->max_key_len = be16_to_cpu(head->max_key_len);
tree->depth = be16_to_cpu(head->depth);
/* Set the correct compare function */
if (id == HFSPLUS_EXT_CNID) {
tree->keycmp = hfsplus_ext_cmp_key;
} else if (id == HFSPLUS_CAT_CNID) {
if ((HFSPLUS_SB(sb).flags & HFSPLUS_SB_HFSX) &&
(head->key_type == HFSPLUS_KEY_BINARY))
tree->keycmp = hfsplus_cat_bin_cmp_key;
else {
tree->keycmp = hfsplus_cat_case_cmp_key;
HFSPLUS_SB(sb).flags |= HFSPLUS_SB_CASEFOLD;
}
} else {
printk(KERN_ERR "hfs: unknown B*Tree requested\n");
goto fail_page;
}
size = tree->node_size;
if (!is_power_of_2(size))
goto fail_page;
if (!tree->node_count)
goto fail_page;
tree->node_size_shift = ffs(size) - 1;
tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
kunmap(page);
page_cache_release(page);
return tree;
fail_page:
tree->inode->i_mapping->a_ops = &hfsplus_aops;
page_cache_release(page);
free_tree:
iput(tree->inode);
kfree(tree);
return NULL;
}
/* Release resources used by a btree */
void hfs_btree_close(struct hfs_btree *tree)
{
struct hfs_bnode *node;
int i;
if (!tree)
return;
for (i = 0; i < NODE_HASH_SIZE; i++) {
while ((node = tree->node_hash[i])) {
tree->node_hash[i] = node->next_hash;
if (atomic_read(&node->refcnt))
printk(KERN_CRIT "hfs: node %d:%d still has %d user(s)!\n",
node->tree->cnid, node->this, atomic_read(&node->refcnt));
hfs_bnode_free(node);
tree->node_hash_cnt--;
}
}
iput(tree->inode);
kfree(tree);
}
void hfs_btree_write(struct hfs_btree *tree)
{
struct hfs_btree_header_rec *head;
struct hfs_bnode *node;
struct page *page;
node = hfs_bnode_find(tree, 0);
if (IS_ERR(node))
/* panic? */
return;
/* Load the header */
page = node->page[0];
head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
head->root = cpu_to_be32(tree->root);
head->leaf_count = cpu_to_be32(tree->leaf_count);
head->leaf_head = cpu_to_be32(tree->leaf_head);
head->leaf_tail = cpu_to_be32(tree->leaf_tail);
head->node_count = cpu_to_be32(tree->node_count);
head->free_nodes = cpu_to_be32(tree->free_nodes);
head->attributes = cpu_to_be32(tree->attributes);
head->depth = cpu_to_be16(tree->depth);
kunmap(page);
set_page_dirty(page);
hfs_bnode_put(node);
}
static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
{
struct hfs_btree *tree = prev->tree;
struct hfs_bnode *node;
struct hfs_bnode_desc desc;
__be32 cnid;
node = hfs_bnode_create(tree, idx);
if (IS_ERR(node))
return node;
tree->free_nodes--;
prev->next = idx;
cnid = cpu_to_be32(idx);
hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
node->type = HFS_NODE_MAP;
node->num_recs = 1;
hfs_bnode_clear(node, 0, tree->node_size);
desc.next = 0;
desc.prev = 0;
desc.type = HFS_NODE_MAP;
desc.height = 0;
desc.num_recs = cpu_to_be16(1);
desc.reserved = 0;
hfs_bnode_write(node, &desc, 0, sizeof(desc));
hfs_bnode_write_u16(node, 14, 0x8000);
hfs_bnode_write_u16(node, tree->node_size - 2, 14);
hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
return node;
}
struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
{
struct hfs_bnode *node, *next_node;
struct page **pagep;
u32 nidx, idx;
unsigned off;
u16 off16;
u16 len;
u8 *data, byte, m;
int i;
while (!tree->free_nodes) {
struct inode *inode = tree->inode;
u32 count;
int res;
res = hfsplus_file_extend(inode);
if (res)
return ERR_PTR(res);
HFSPLUS_I(inode).phys_size = inode->i_size =
(loff_t)HFSPLUS_I(inode).alloc_blocks <<
HFSPLUS_SB(tree->sb).alloc_blksz_shift;
HFSPLUS_I(inode).fs_blocks = HFSPLUS_I(inode).alloc_blocks <<
HFSPLUS_SB(tree->sb).fs_shift;
inode_set_bytes(inode, inode->i_size);
count = inode->i_size >> tree->node_size_shift;
tree->free_nodes = count - tree->node_count;
tree->node_count = count;
}
nidx = 0;
node = hfs_bnode_find(tree, nidx);
if (IS_ERR(node))
return node;
len = hfs_brec_lenoff(node, 2, &off16);
off = off16;
off += node->page_offset;
pagep = node->page + (off >> PAGE_CACHE_SHIFT);
data = kmap(*pagep);
off &= ~PAGE_CACHE_MASK;
idx = 0;
for (;;) {
while (len) {
byte = data[off];
if (byte != 0xff) {
for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
if (!(byte & m)) {
idx += i;
data[off] |= m;
set_page_dirty(*pagep);
kunmap(*pagep);
tree->free_nodes--;
mark_inode_dirty(tree->inode);
hfs_bnode_put(node);
return hfs_bnode_create(tree, idx);
}
}
}
if (++off >= PAGE_CACHE_SIZE) {
kunmap(*pagep);
data = kmap(*++pagep);
off = 0;
}
idx += 8;
len--;
}
kunmap(*pagep);
nidx = node->next;
if (!nidx) {
printk(KERN_DEBUG "hfs: create new bmap node...\n");
next_node = hfs_bmap_new_bmap(node, idx);
} else
next_node = hfs_bnode_find(tree, nidx);
hfs_bnode_put(node);
if (IS_ERR(next_node))
return next_node;
node = next_node;
len = hfs_brec_lenoff(node, 0, &off16);
off = off16;
off += node->page_offset;
pagep = node->page + (off >> PAGE_CACHE_SHIFT);
data = kmap(*pagep);
off &= ~PAGE_CACHE_MASK;
}
}
void hfs_bmap_free(struct hfs_bnode *node)
{
struct hfs_btree *tree;
struct page *page;
u16 off, len;
u32 nidx;
u8 *data, byte, m;
dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
BUG_ON(!node->this);
tree = node->tree;
nidx = node->this;
node = hfs_bnode_find(tree, 0);
if (IS_ERR(node))
return;
len = hfs_brec_lenoff(node, 2, &off);
while (nidx >= len * 8) {
u32 i;
nidx -= len * 8;
i = node->next;
hfs_bnode_put(node);
if (!i) {
/* panic */;
printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this);
return;
}
node = hfs_bnode_find(tree, i);
if (IS_ERR(node))
return;
if (node->type != HFS_NODE_MAP) {
/* panic */;
printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type);
hfs_bnode_put(node);
return;
}
len = hfs_brec_lenoff(node, 0, &off);
}
off += node->page_offset + nidx / 8;
page = node->page[off >> PAGE_CACHE_SHIFT];
data = kmap(page);
off &= ~PAGE_CACHE_MASK;
m = 1 << (~nidx & 7);
byte = data[off];
if (!(byte & m)) {
printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type);
kunmap(page);
hfs_bnode_put(node);
return;
}
data[off] = byte & ~m;
set_page_dirty(page);
kunmap(page);
hfs_bnode_put(node);
tree->free_nodes++;
mark_inode_dirty(tree->inode);
}