linux/fs/btrfs/disk-io.c

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#include <linux/module.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include <linux/swap.h>
#include <linux/radix-tree.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
{
struct btrfs_node *node = btrfs_buffer_node(buf);
if (buf->b_blocknr != btrfs_header_blocknr(&node->header)) {
BUG();
}
return 0;
}
struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr)
{
struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
int blockbits = root->fs_info->sb->s_blocksize_bits;
unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
struct page *page;
struct buffer_head *bh;
struct buffer_head *head;
struct buffer_head *ret = NULL;
page = find_lock_page(mapping, index);
if (!page)
return NULL;
if (!page_has_buffers(page))
goto out_unlock;
head = page_buffers(page);
bh = head;
do {
if (buffer_mapped(bh) && bh->b_blocknr == blocknr) {
ret = bh;
get_bh(bh);
goto out_unlock;
}
bh = bh->b_this_page;
} while (bh != head);
out_unlock:
unlock_page(page);
if (ret) {
touch_buffer(ret);
}
page_cache_release(page);
return ret;
}
struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root,
u64 blocknr)
{
struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
int blockbits = root->fs_info->sb->s_blocksize_bits;
unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
struct page *page;
struct buffer_head *bh;
struct buffer_head *head;
struct buffer_head *ret = NULL;
u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);
page = grab_cache_page(mapping, index);
if (!page)
return NULL;
if (!page_has_buffers(page))
create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0);
head = page_buffers(page);
bh = head;
do {
if (!buffer_mapped(bh)) {
bh->b_bdev = root->fs_info->sb->s_bdev;
bh->b_blocknr = first_block;
set_buffer_mapped(bh);
}
if (bh->b_blocknr == blocknr) {
ret = bh;
get_bh(bh);
goto out_unlock;
}
bh = bh->b_this_page;
first_block++;
} while (bh != head);
out_unlock:
unlock_page(page);
if (ret)
touch_buffer(ret);
page_cache_release(page);
return ret;
}
static sector_t max_block(struct block_device *bdev)
{
sector_t retval = ~((sector_t)0);
loff_t sz = i_size_read(bdev->bd_inode);
if (sz) {
unsigned int size = block_size(bdev);
unsigned int sizebits = blksize_bits(size);
retval = (sz >> sizebits);
}
return retval;
}
static int btree_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh, int create)
{
if (iblock >= max_block(inode->i_sb->s_bdev)) {
if (create)
return -EIO;
/*
* for reads, we're just trying to fill a partial page.
* return a hole, they will have to call get_block again
* before they can fill it, and they will get -EIO at that
* time
*/
return 0;
}
bh->b_bdev = inode->i_sb->s_bdev;
bh->b_blocknr = iblock;
set_buffer_mapped(bh);
return 0;
}
int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
char *result)
{
struct scatterlist sg;
struct crypto_hash *tfm = root->fs_info->hash_tfm;
struct hash_desc desc;
int ret;
desc.tfm = tfm;
desc.flags = 0;
sg_init_one(&sg, data, len);
spin_lock(&root->fs_info->hash_lock);
ret = crypto_hash_digest(&desc, &sg, 1, result);
spin_unlock(&root->fs_info->hash_lock);
if (ret) {
printk("sha256 digest failed\n");
}
return ret;
}
static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh,
int verify)
{
char result[BTRFS_CSUM_SIZE];
int ret;
struct btrfs_node *node;
ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE,
bh->b_size - BTRFS_CSUM_SIZE, result);
if (ret)
return ret;
if (verify) {
if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) {
printk("checksum verify failed on %lu\n",
bh->b_blocknr);
return 1;
}
} else {
node = btrfs_buffer_node(bh);
memcpy(node->header.csum, result, BTRFS_CSUM_SIZE);
}
return 0;
}
static int btree_writepage(struct page *page, struct writeback_control *wbc)
{
struct buffer_head *bh;
struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
struct buffer_head *head;
if (!page_has_buffers(page)) {
create_empty_buffers(page, root->fs_info->sb->s_blocksize,
(1 << BH_Dirty)|(1 << BH_Uptodate));
}
head = page_buffers(page);
bh = head;
do {
if (buffer_dirty(bh))
csum_tree_block(root, bh, 0);
bh = bh->b_this_page;
} while (bh != head);
return block_write_full_page(page, btree_get_block, wbc);
}
static int btree_readpage(struct file * file, struct page * page)
{
return block_read_full_page(page, btree_get_block);
}
static struct address_space_operations btree_aops = {
.readpage = btree_readpage,
.writepage = btree_writepage,
.sync_page = block_sync_page,
};
struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr)
{
struct buffer_head *bh = NULL;
bh = btrfs_find_create_tree_block(root, blocknr);
if (!bh)
return bh;
if (buffer_uptodate(bh))
goto uptodate;
lock_buffer(bh);
if (!buffer_uptodate(bh)) {
get_bh(bh);
bh->b_end_io = end_buffer_read_sync;
submit_bh(READ, bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh))
goto fail;
csum_tree_block(root, bh, 1);
} else {
unlock_buffer(bh);
}
uptodate:
if (check_tree_block(root, bh))
BUG();
return bh;
fail:
brelse(bh);
return NULL;
}
int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct buffer_head *buf)
{
WARN_ON(atomic_read(&buf->b_count) == 0);
mark_buffer_dirty(buf);
return 0;
}
int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct buffer_head *buf)
{
WARN_ON(atomic_read(&buf->b_count) == 0);
clear_buffer_dirty(buf);
return 0;
}
static int __setup_root(int blocksize,
struct btrfs_root *root,
struct btrfs_fs_info *fs_info,
u64 objectid)
{
root->node = NULL;
root->inode = NULL;
root->commit_root = NULL;
root->blocksize = blocksize;
root->ref_cows = 0;
root->fs_info = fs_info;
root->objectid = objectid;
root->last_trans = 0;
root->highest_inode = 0;
root->last_inode_alloc = 0;
memset(&root->root_key, 0, sizeof(root->root_key));
memset(&root->root_item, 0, sizeof(root->root_item));
return 0;
}
static int find_and_setup_root(int blocksize,
struct btrfs_root *tree_root,
struct btrfs_fs_info *fs_info,
u64 objectid,
struct btrfs_root *root)
{
int ret;
__setup_root(blocksize, root, fs_info, objectid);
ret = btrfs_find_last_root(tree_root, objectid,
&root->root_item, &root->root_key);
BUG_ON(ret);
root->node = read_tree_block(root,
btrfs_root_blocknr(&root->root_item));
BUG_ON(!root->node);
return 0;
}
struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
struct btrfs_key *location)
{
struct btrfs_root *root;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_path *path;
struct btrfs_leaf *l;
u64 highest_inode;
int ret = 0;
printk("read_fs_root looking for %Lu %Lu %u\n", location->objectid, location->offset, location->flags);
root = kmalloc(sizeof(*root), GFP_NOFS);
if (!root) {
printk("failed1\n");
return ERR_PTR(-ENOMEM);
}
if (location->offset == (u64)-1) {
ret = find_and_setup_root(fs_info->sb->s_blocksize,
fs_info->tree_root, fs_info,
location->objectid, root);
if (ret) {
printk("failed2\n");
kfree(root);
return ERR_PTR(ret);
}
goto insert;
}
__setup_root(fs_info->sb->s_blocksize, root, fs_info,
location->objectid);
path = btrfs_alloc_path();
BUG_ON(!path);
ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
if (ret != 0) {
printk("internal search_slot gives us %d\n", ret);
if (ret > 0)
ret = -ENOENT;
goto out;
}
l = btrfs_buffer_leaf(path->nodes[0]);
memcpy(&root->root_item,
btrfs_item_ptr(l, path->slots[0], struct btrfs_root_item),
sizeof(root->root_item));
memcpy(&root->root_key, location, sizeof(*location));
ret = 0;
out:
btrfs_release_path(root, path);
btrfs_free_path(path);
if (ret) {
kfree(root);
return ERR_PTR(ret);
}
root->node = read_tree_block(root,
btrfs_root_blocknr(&root->root_item));
BUG_ON(!root->node);
insert:
printk("inserting %p\n", root);
root->ref_cows = 1;
ret = radix_tree_insert(&fs_info->fs_roots_radix, (unsigned long)root,
root);
if (ret) {
printk("radix_tree_insert gives us %d\n", ret);
brelse(root->node);
kfree(root);
return ERR_PTR(ret);
}
ret = btrfs_find_highest_inode(root, &highest_inode);
if (ret == 0) {
root->highest_inode = highest_inode;
root->last_inode_alloc = highest_inode;
printk("highest inode is %Lu\n", highest_inode);
}
printk("all worked\n");
return root;
}
struct btrfs_root *open_ctree(struct super_block *sb)
{
struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
GFP_NOFS);
struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
GFP_NOFS);
struct btrfs_fs_info *fs_info = kmalloc(sizeof(*fs_info),
GFP_NOFS);
int ret;
struct btrfs_super_block *disk_super;
init_bit_radix(&fs_info->pinned_radix);
init_bit_radix(&fs_info->pending_del_radix);
INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
sb_set_blocksize(sb, 4096);
fs_info->running_transaction = NULL;
fs_info->tree_root = tree_root;
fs_info->extent_root = extent_root;
fs_info->sb = sb;
fs_info->btree_inode = new_inode(sb);
fs_info->btree_inode->i_ino = 1;
fs_info->btree_inode->i_nlink = 1;
fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
BTRFS_I(fs_info->btree_inode)->root = tree_root;
memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
sizeof(struct btrfs_key));
insert_inode_hash(fs_info->btree_inode);
mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
fs_info->hash_tfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC);
spin_lock_init(&fs_info->hash_lock);
if (!fs_info->hash_tfm || IS_ERR(fs_info->hash_tfm)) {
printk("failed to allocate sha256 hash\n");
return NULL;
}
mutex_init(&fs_info->trans_mutex);
mutex_init(&fs_info->fs_mutex);
memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
__setup_root(sb->s_blocksize, tree_root,
fs_info, BTRFS_ROOT_TREE_OBJECTID);
fs_info->sb_buffer = read_tree_block(tree_root,
BTRFS_SUPER_INFO_OFFSET /
sb->s_blocksize);
if (!fs_info->sb_buffer)
return NULL;
disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
if (!btrfs_super_root(disk_super))
return NULL;
fs_info->disk_super = disk_super;
tree_root->node = read_tree_block(tree_root,
btrfs_super_root(disk_super));
BUG_ON(!tree_root->node);
mutex_lock(&fs_info->fs_mutex);
ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info,
BTRFS_EXTENT_TREE_OBJECTID, extent_root);
BUG_ON(ret);
fs_info->generation = btrfs_super_generation(disk_super) + 1;
memset(&fs_info->kobj, 0, sizeof(fs_info->kobj));
kobj_set_kset_s(fs_info, btrfs_subsys);
kobject_set_name(&fs_info->kobj, "%s", sb->s_id);
kobject_register(&fs_info->kobj);
mutex_unlock(&fs_info->fs_mutex);
return tree_root;
}
int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
*root)
{
struct buffer_head *bh = root->fs_info->sb_buffer;
btrfs_set_super_root(root->fs_info->disk_super,
root->fs_info->tree_root->node->b_blocknr);
lock_buffer(bh);
WARN_ON(atomic_read(&bh->b_count) < 1);
clear_buffer_dirty(bh);
csum_tree_block(root, bh, 0);
bh->b_end_io = end_buffer_write_sync;
get_bh(bh);
submit_bh(WRITE, bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh)) {
WARN_ON(1);
return -EIO;
}
return 0;
}
int del_fs_roots(struct btrfs_fs_info *fs_info)
{
int ret;
struct btrfs_root *gang[8];
int i;
while(1) {
ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
(void **)gang, 0,
ARRAY_SIZE(gang));
if (!ret)
break;
for (i = 0; i < ret; i++) {
radix_tree_delete(&fs_info->fs_roots_radix,
(unsigned long)gang[i]);
if (gang[i]->inode)
iput(gang[i]->inode);
else
printk("no inode for root %p\n", gang[i]);
if (gang[i]->node)
brelse(gang[i]->node);
if (gang[i]->commit_root)
brelse(gang[i]->commit_root);
kfree(gang[i]);
}
}
return 0;
}
int close_ctree(struct btrfs_root *root)
{
int ret;
struct btrfs_trans_handle *trans;
struct btrfs_fs_info *fs_info = root->fs_info;
mutex_lock(&fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_commit_transaction(trans, root);
/* run commit again to drop the original snapshot */
trans = btrfs_start_transaction(root, 1);
btrfs_commit_transaction(trans, root);
ret = btrfs_write_and_wait_transaction(NULL, root);
BUG_ON(ret);
write_ctree_super(NULL, root);
mutex_unlock(&fs_info->fs_mutex);
if (fs_info->extent_root->node)
btrfs_block_release(fs_info->extent_root,
fs_info->extent_root->node);
if (fs_info->tree_root->node)
btrfs_block_release(fs_info->tree_root,
fs_info->tree_root->node);
btrfs_block_release(root, fs_info->sb_buffer);
crypto_free_hash(fs_info->hash_tfm);
truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
iput(fs_info->btree_inode);
del_fs_roots(fs_info);
kfree(fs_info->extent_root);
kfree(fs_info->tree_root);
kobject_unregister(&fs_info->kobj);
return 0;
}
void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf)
{
brelse(buf);
}