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DEFINITIONS
This source file includes following definitions.
- hfs_bnode_read
- hfs_bnode_read_u16
- hfs_bnode_read_u8
- hfs_bnode_read_key
- hfs_bnode_write
- hfs_bnode_write_u16
- hfs_bnode_write_u8
- hfs_bnode_clear
- hfs_bnode_copy
- hfs_bnode_move
- hfs_bnode_dump
- hfs_bnode_unlink
- hfs_bnode_hash
- hfs_bnode_findhash
- __hfs_bnode_create
- hfs_bnode_unhash
- hfs_bnode_find
- hfs_bnode_free
- hfs_bnode_create
- hfs_bnode_get
- hfs_bnode_put
/*
* linux/fs/hfs/bnode.c
*
* Copyright (C) 2001
* Brad Boyer (flar@allandria.com)
* (C) 2003 Ardis Technologies <roman@ardistech.com>
*
* Handle basic btree node operations
*/
#include <linux/pagemap.h>
#include <linux/swap.h>
#include "btree.h"
void hfs_bnode_read(struct hfs_bnode *node, void *buf,
int off, int len)
{
struct page *page;
off += node->page_offset;
page = node->page[0];
memcpy(buf, kmap(page) + off, len);
kunmap(page);
}
u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
{
__be16 data;
// optimize later...
hfs_bnode_read(node, &data, off, 2);
return be16_to_cpu(data);
}
u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
{
u8 data;
// optimize later...
hfs_bnode_read(node, &data, off, 1);
return data;
}
void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
{
struct hfs_btree *tree;
int key_len;
tree = node->tree;
if (node->type == HFS_NODE_LEAF ||
tree->attributes & HFS_TREE_VARIDXKEYS)
key_len = hfs_bnode_read_u8(node, off) + 1;
else
key_len = tree->max_key_len + 1;
hfs_bnode_read(node, key, off, key_len);
}
void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
{
struct page *page;
off += node->page_offset;
page = node->page[0];
memcpy(kmap(page) + off, buf, len);
kunmap(page);
set_page_dirty(page);
}
void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
{
__be16 v = cpu_to_be16(data);
// optimize later...
hfs_bnode_write(node, &v, off, 2);
}
void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
{
// optimize later...
hfs_bnode_write(node, &data, off, 1);
}
void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
{
struct page *page;
off += node->page_offset;
page = node->page[0];
memset(kmap(page) + off, 0, len);
kunmap(page);
set_page_dirty(page);
}
void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
struct hfs_bnode *src_node, int src, int len)
{
struct hfs_btree *tree;
struct page *src_page, *dst_page;
dprint(DBG_BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
if (!len)
return;
tree = src_node->tree;
src += src_node->page_offset;
dst += dst_node->page_offset;
src_page = src_node->page[0];
dst_page = dst_node->page[0];
memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
kunmap(src_page);
kunmap(dst_page);
set_page_dirty(dst_page);
}
void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
{
struct page *page;
void *ptr;
dprint(DBG_BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
if (!len)
return;
src += node->page_offset;
dst += node->page_offset;
page = node->page[0];
ptr = kmap(page);
memmove(ptr + dst, ptr + src, len);
kunmap(page);
set_page_dirty(page);
}
void hfs_bnode_dump(struct hfs_bnode *node)
{
struct hfs_bnode_desc desc;
__be32 cnid;
int i, off, key_off;
dprint(DBG_BNODE_MOD, "bnode: %d\n", node->this);
hfs_bnode_read(node, &desc, 0, sizeof(desc));
dprint(DBG_BNODE_MOD, "%d, %d, %d, %d, %d\n",
be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
desc.type, desc.height, be16_to_cpu(desc.num_recs));
off = node->tree->node_size - 2;
for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
key_off = hfs_bnode_read_u16(node, off);
dprint(DBG_BNODE_MOD, " %d", key_off);
if (i && node->type == HFS_NODE_INDEX) {
int tmp;
if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
else
tmp = node->tree->max_key_len + 1;
dprint(DBG_BNODE_MOD, " (%d,%d", tmp, hfs_bnode_read_u8(node, key_off));
hfs_bnode_read(node, &cnid, key_off + tmp, 4);
dprint(DBG_BNODE_MOD, ",%d)", be32_to_cpu(cnid));
} else if (i && node->type == HFS_NODE_LEAF) {
int tmp;
tmp = hfs_bnode_read_u8(node, key_off);
dprint(DBG_BNODE_MOD, " (%d)", tmp);
}
}
dprint(DBG_BNODE_MOD, "\n");
}
void hfs_bnode_unlink(struct hfs_bnode *node)
{
struct hfs_btree *tree;
struct hfs_bnode *tmp;
__be32 cnid;
tree = node->tree;
if (node->prev) {
tmp = hfs_bnode_find(tree, node->prev);
if (IS_ERR(tmp))
return;
tmp->next = node->next;
cnid = cpu_to_be32(tmp->next);
hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
hfs_bnode_put(tmp);
} else if (node->type == HFS_NODE_LEAF)
tree->leaf_head = node->next;
if (node->next) {
tmp = hfs_bnode_find(tree, node->next);
if (IS_ERR(tmp))
return;
tmp->prev = node->prev;
cnid = cpu_to_be32(tmp->prev);
hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
hfs_bnode_put(tmp);
} else if (node->type == HFS_NODE_LEAF)
tree->leaf_tail = node->prev;
// move down?
if (!node->prev && !node->next) {
printk(KERN_DEBUG "hfs_btree_del_level\n");
}
if (!node->parent) {
tree->root = 0;
tree->depth = 0;
}
set_bit(HFS_BNODE_DELETED, &node->flags);
}
static inline int hfs_bnode_hash(u32 num)
{
num = (num >> 16) + num;
num += num >> 8;
return num & (NODE_HASH_SIZE - 1);
}
struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
{
struct hfs_bnode *node;
if (cnid >= tree->node_count) {
printk(KERN_ERR "hfs: request for non-existent node %d in B*Tree\n", cnid);
return NULL;
}
for (node = tree->node_hash[hfs_bnode_hash(cnid)];
node; node = node->next_hash) {
if (node->this == cnid) {
return node;
}
}
return NULL;
}
static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
{
struct super_block *sb;
struct hfs_bnode *node, *node2;
struct address_space *mapping;
struct page *page;
int size, block, i, hash;
loff_t off;
if (cnid >= tree->node_count) {
printk(KERN_ERR "hfs: request for non-existent node %d in B*Tree\n", cnid);
return NULL;
}
sb = tree->inode->i_sb;
size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
sizeof(struct page *);
node = kzalloc(size, GFP_KERNEL);
if (!node)
return NULL;
node->tree = tree;
node->this = cnid;
set_bit(HFS_BNODE_NEW, &node->flags);
atomic_set(&node->refcnt, 1);
dprint(DBG_BNODE_REFS, "new_node(%d:%d): 1\n",
node->tree->cnid, node->this);
init_waitqueue_head(&node->lock_wq);
spin_lock(&tree->hash_lock);
node2 = hfs_bnode_findhash(tree, cnid);
if (!node2) {
hash = hfs_bnode_hash(cnid);
node->next_hash = tree->node_hash[hash];
tree->node_hash[hash] = node;
tree->node_hash_cnt++;
} else {
spin_unlock(&tree->hash_lock);
kfree(node);
wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
return node2;
}
spin_unlock(&tree->hash_lock);
mapping = tree->inode->i_mapping;
off = (loff_t)cnid * tree->node_size;
block = off >> PAGE_CACHE_SHIFT;
node->page_offset = off & ~PAGE_CACHE_MASK;
for (i = 0; i < tree->pages_per_bnode; i++) {
page = read_mapping_page(mapping, block++, NULL);
if (IS_ERR(page))
goto fail;
if (PageError(page)) {
page_cache_release(page);
goto fail;
}
page_cache_release(page);
node->page[i] = page;
}
return node;
fail:
set_bit(HFS_BNODE_ERROR, &node->flags);
return node;
}
void hfs_bnode_unhash(struct hfs_bnode *node)
{
struct hfs_bnode **p;
dprint(DBG_BNODE_REFS, "remove_node(%d:%d): %d\n",
node->tree->cnid, node->this, atomic_read(&node->refcnt));
for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
*p && *p != node; p = &(*p)->next_hash)
;
BUG_ON(!*p);
*p = node->next_hash;
node->tree->node_hash_cnt--;
}
/* Load a particular node out of a tree */
struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
{
struct hfs_bnode *node;
struct hfs_bnode_desc *desc;
int i, rec_off, off, next_off;
int entry_size, key_size;
spin_lock(&tree->hash_lock);
node = hfs_bnode_findhash(tree, num);
if (node) {
hfs_bnode_get(node);
spin_unlock(&tree->hash_lock);
wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
if (test_bit(HFS_BNODE_ERROR, &node->flags))
goto node_error;
return node;
}
spin_unlock(&tree->hash_lock);
node = __hfs_bnode_create(tree, num);
if (!node)
return ERR_PTR(-ENOMEM);
if (test_bit(HFS_BNODE_ERROR, &node->flags))
goto node_error;
if (!test_bit(HFS_BNODE_NEW, &node->flags))
return node;
desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
node->prev = be32_to_cpu(desc->prev);
node->next = be32_to_cpu(desc->next);
node->num_recs = be16_to_cpu(desc->num_recs);
node->type = desc->type;
node->height = desc->height;
kunmap(node->page[0]);
switch (node->type) {
case HFS_NODE_HEADER:
case HFS_NODE_MAP:
if (node->height != 0)
goto node_error;
break;
case HFS_NODE_LEAF:
if (node->height != 1)
goto node_error;
break;
case HFS_NODE_INDEX:
if (node->height <= 1 || node->height > tree->depth)
goto node_error;
break;
default:
goto node_error;
}
rec_off = tree->node_size - 2;
off = hfs_bnode_read_u16(node, rec_off);
if (off != sizeof(struct hfs_bnode_desc))
goto node_error;
for (i = 1; i <= node->num_recs; off = next_off, i++) {
rec_off -= 2;
next_off = hfs_bnode_read_u16(node, rec_off);
if (next_off <= off ||
next_off > tree->node_size ||
next_off & 1)
goto node_error;
entry_size = next_off - off;
if (node->type != HFS_NODE_INDEX &&
node->type != HFS_NODE_LEAF)
continue;
key_size = hfs_bnode_read_u8(node, off) + 1;
if (key_size >= entry_size /*|| key_size & 1*/)
goto node_error;
}
clear_bit(HFS_BNODE_NEW, &node->flags);
wake_up(&node->lock_wq);
return node;
node_error:
set_bit(HFS_BNODE_ERROR, &node->flags);
clear_bit(HFS_BNODE_NEW, &node->flags);
wake_up(&node->lock_wq);
hfs_bnode_put(node);
return ERR_PTR(-EIO);
}
void hfs_bnode_free(struct hfs_bnode *node)
{
//int i;
//for (i = 0; i < node->tree->pages_per_bnode; i++)
// if (node->page[i])
// page_cache_release(node->page[i]);
kfree(node);
}
struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
{
struct hfs_bnode *node;
struct page **pagep;
int i;
spin_lock(&tree->hash_lock);
node = hfs_bnode_findhash(tree, num);
spin_unlock(&tree->hash_lock);
BUG_ON(node);
node = __hfs_bnode_create(tree, num);
if (!node)
return ERR_PTR(-ENOMEM);
if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
hfs_bnode_put(node);
return ERR_PTR(-EIO);
}
pagep = node->page;
memset(kmap(*pagep) + node->page_offset, 0,
min((int)PAGE_CACHE_SIZE, (int)tree->node_size));
set_page_dirty(*pagep);
kunmap(*pagep);
for (i = 1; i < tree->pages_per_bnode; i++) {
memset(kmap(*++pagep), 0, PAGE_CACHE_SIZE);
set_page_dirty(*pagep);
kunmap(*pagep);
}
clear_bit(HFS_BNODE_NEW, &node->flags);
wake_up(&node->lock_wq);
return node;
}
void hfs_bnode_get(struct hfs_bnode *node)
{
if (node) {
atomic_inc(&node->refcnt);
dprint(DBG_BNODE_REFS, "get_node(%d:%d): %d\n",
node->tree->cnid, node->this, atomic_read(&node->refcnt));
}
}
/* Dispose of resources used by a node */
void hfs_bnode_put(struct hfs_bnode *node)
{
if (node) {
struct hfs_btree *tree = node->tree;
int i;
dprint(DBG_BNODE_REFS, "put_node(%d:%d): %d\n",
node->tree->cnid, node->this, atomic_read(&node->refcnt));
BUG_ON(!atomic_read(&node->refcnt));
if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
return;
for (i = 0; i < tree->pages_per_bnode; i++) {
if (!node->page[i])
continue;
mark_page_accessed(node->page[i]);
}
if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
hfs_bnode_unhash(node);
spin_unlock(&tree->hash_lock);
hfs_bmap_free(node);
hfs_bnode_free(node);
return;
}
spin_unlock(&tree->hash_lock);
}
}