- 根目录:
- fs
- hfsplus
- btree.c
/*
* 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"
/*
* Initial source code of clump size calculation is gotten
* from http://opensource.apple.com/tarballs/diskdev_cmds/
*/
#define CLUMP_ENTRIES 15
static short clumptbl[CLUMP_ENTRIES * 3] = {
/*
* Volume Attributes Catalog Extents
* Size Clump (MB) Clump (MB) Clump (MB)
*/
/* 1GB */ 4, 4, 4,
/* 2GB */ 6, 6, 4,
/* 4GB */ 8, 8, 4,
/* 8GB */ 11, 11, 5,
/*
* For volumes 16GB and larger, we want to make sure that a full OS
* install won't require fragmentation of the Catalog or Attributes
* B-trees. We do this by making the clump sizes sufficiently large,
* and by leaving a gap after the B-trees for them to grow into.
*
* For SnowLeopard 10A298, a FullNetInstall with all packages selected
* results in:
* Catalog B-tree Header
* nodeSize: 8192
* totalNodes: 31616
* freeNodes: 1978
* (used = 231.55 MB)
* Attributes B-tree Header
* nodeSize: 8192
* totalNodes: 63232
* freeNodes: 958
* (used = 486.52 MB)
*
* We also want Time Machine backup volumes to have a sufficiently
* large clump size to reduce fragmentation.
*
* The series of numbers for Catalog and Attribute form a geometric
* series. For Catalog (16GB to 512GB), each term is 8**(1/5) times
* the previous term. For Attributes (16GB to 512GB), each term is
* 4**(1/5) times the previous term. For 1TB to 16TB, each term is
* 2**(1/5) times the previous term.
*/
/* 16GB */ 64, 32, 5,
/* 32GB */ 84, 49, 6,
/* 64GB */ 111, 74, 7,
/* 128GB */ 147, 111, 8,
/* 256GB */ 194, 169, 9,
/* 512GB */ 256, 256, 11,
/* 1TB */ 294, 294, 14,
/* 2TB */ 338, 338, 16,
/* 4TB */ 388, 388, 20,
/* 8TB */ 446, 446, 25,
/* 16TB */ 512, 512, 32
};
u32 hfsplus_calc_btree_clump_size(u32 block_size, u32 node_size,
u64 sectors, int file_id)
{
u32 mod = max(node_size, block_size);
u32 clump_size;
int column;
int i;
/* Figure out which column of the above table to use for this file. */
switch (file_id) {
case HFSPLUS_ATTR_CNID:
column = 0;
break;
case HFSPLUS_CAT_CNID:
column = 1;
break;
default:
column = 2;
break;
}
/*
* The default clump size is 0.8% of the volume size. And
* it must also be a multiple of the node and block size.
*/
if (sectors < 0x200000) {
clump_size = sectors << 2; /* 0.8 % */
if (clump_size < (8 * node_size))
clump_size = 8 * node_size;
} else {
/* turn exponent into table index... */
for (i = 0, sectors = sectors >> 22;
sectors && (i < CLUMP_ENTRIES - 1);
++i, sectors = sectors >> 1) {
/* empty body */
}
clump_size = clumptbl[column + (i) * 3] * 1024 * 1024;
}
/*
* Round the clump size to a multiple of node and block size.
* NOTE: This rounds down.
*/
clump_size /= mod;
clump_size *= mod;
/*
* Rounding down could have rounded down to 0 if the block size was
* greater than the clump size. If so, just use one block or node.
*/
if (clump_size == 0)
clump_size = mod;
return clump_size;
}
/* 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;
mutex_init(&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;
if (!HFSPLUS_I(tree->inode)->first_blocks) {
pr_err("invalid btree extent records (0 size)\n");
goto free_inode;
}
mapping = tree->inode->i_mapping;
page = read_mapping_page(mapping, 0, NULL);
if (IS_ERR(page))
goto free_inode;
/* 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);
/* Verify the tree and set the correct compare function */
switch (id) {
case HFSPLUS_EXT_CNID:
if (tree->max_key_len != HFSPLUS_EXT_KEYLEN - sizeof(u16)) {
pr_err("invalid extent max_key_len %d\n",
tree->max_key_len);
goto fail_page;
}
if (tree->attributes & HFS_TREE_VARIDXKEYS) {
pr_err("invalid extent btree flag\n");
goto fail_page;
}
tree->keycmp = hfsplus_ext_cmp_key;
break;
case HFSPLUS_CAT_CNID:
if (tree->max_key_len != HFSPLUS_CAT_KEYLEN - sizeof(u16)) {
pr_err("invalid catalog max_key_len %d\n",
tree->max_key_len);
goto fail_page;
}
if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
pr_err("invalid catalog btree flag\n");
goto fail_page;
}
if (test_bit(HFSPLUS_SB_HFSX, &HFSPLUS_SB(sb)->flags) &&
(head->key_type == HFSPLUS_KEY_BINARY))
tree->keycmp = hfsplus_cat_bin_cmp_key;
else {
tree->keycmp = hfsplus_cat_case_cmp_key;
set_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
}
break;
case HFSPLUS_ATTR_CNID:
if (tree->max_key_len != HFSPLUS_ATTR_KEYLEN - sizeof(u16)) {
pr_err("invalid attributes max_key_len %d\n",
tree->max_key_len);
goto fail_page;
}
tree->keycmp = hfsplus_attr_bin_cmp_key;
break;
default:
pr_err("unknown B*Tree requested\n");
goto fail_page;
}
if (!(tree->attributes & HFS_TREE_BIGKEYS)) {
pr_err("invalid btree flag\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:
page_cache_release(page);
free_inode:
tree->inode->i_mapping->a_ops = &hfsplus_aops;
iput(tree->inode);
free_tree:
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))
pr_crit("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);
}
int 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 -EIO;
/* 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);
return 0;
}
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;
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
u32 count;
int res;
res = hfsplus_file_extend(inode);
if (res)
return ERR_PTR(res);
hip->phys_size = inode->i_size =
(loff_t)hip->alloc_blocks <<
HFSPLUS_SB(tree->sb)->alloc_blksz_shift;
hip->fs_blocks =
hip->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) {
hfs_dbg(BNODE_MOD, "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;
hfs_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 */;
pr_crit("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 */;
pr_crit("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)) {
pr_crit("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);
}