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"
struct dev_lookup {
u64 block_start;
u64 num_blocks;
u64 device_id;
struct block_device *bdev;
};
int btrfs_insert_dev_radix(struct btrfs_root *root,
struct block_device *bdev,
u64 device_id,
u64 block_start,
u64 num_blocks)
{
struct dev_lookup *lookup;
int ret;
lookup = kmalloc(sizeof(*lookup), GFP_NOFS);
if (!lookup)
return -ENOMEM;
lookup->block_start = block_start;
lookup->num_blocks = num_blocks;
lookup->bdev = bdev;
lookup->device_id = device_id;
ret = radix_tree_insert(&root->fs_info->dev_radix, block_start +
num_blocks - 1, lookup);
return ret;
}
u64 bh_blocknr(struct buffer_head *bh)
{
int blkbits = bh->b_page->mapping->host->i_blkbits;
u64 blocknr = bh->b_page->index << (PAGE_CACHE_SHIFT - blkbits);
unsigned long offset;
if (PageHighMem(bh->b_page))
offset = (unsigned long)bh->b_data;
else
offset = bh->b_data - (char *)page_address(bh->b_page);
blocknr += offset >> (PAGE_CACHE_SHIFT - blkbits);
return blocknr;
}
static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
{
struct btrfs_node *node = btrfs_buffer_node(buf);
if (bh_blocknr(buf) != btrfs_header_blocknr(&node->header)) {
printk(KERN_CRIT "bh_blocknr(buf) is %Lu, header is %Lu\n",
bh_blocknr(buf), 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_blocknr(bh) == 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;
}
int btrfs_map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
u64 logical)
{
struct dev_lookup *lookup[2];
int ret;
if (logical == 0) {
bh->b_bdev = NULL;
bh->b_blocknr = 0;
set_buffer_mapped(bh);
return 0;
}
root = root->fs_info->dev_root;
ret = radix_tree_gang_lookup(&root->fs_info->dev_radix,
(void **)lookup,
(unsigned long)logical,
ARRAY_SIZE(lookup));
if (ret == 0 || lookup[0]->block_start > logical ||
lookup[0]->block_start + lookup[0]->num_blocks <= logical) {
ret = -ENOENT;
goto out;
}
bh->b_bdev = lookup[0]->bdev;
bh->b_blocknr = logical - lookup[0]->block_start;
set_buffer_mapped(bh);
ret = 0;
out:
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;
int err;
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)) {
err = btrfs_map_bh_to_logical(root, bh, first_block);
BUG_ON(err);
}
if (bh_blocknr(bh) == 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 int btree_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh, int create)
{
int err;
struct btrfs_root *root = BTRFS_I(bh->b_page->mapping->host)->root;
err = btrfs_map_bh_to_logical(root, bh, iblock);
return err;
}
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_blocknr(bh));
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 = radix_tree_lookup(&fs_info->fs_roots_radix,
(unsigned long)location->objectid);
if (root) {
printk("found %p in cache\n", root);
return root;
}
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_key.objectid,
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;
}
static int btrfs_open_disk(struct btrfs_root *root, u64 device_id,
u64 block_start, u64 num_blocks,
char *filename, int name_len)
{
char *null_filename;
struct block_device *bdev;
int ret;
null_filename = kmalloc(name_len + 1, GFP_NOFS);
if (!null_filename)
return -ENOMEM;
memcpy(null_filename, filename, name_len);
null_filename[name_len] = '\0';
bdev = open_bdev_excl(null_filename, O_RDWR, root->fs_info->sb);
if (IS_ERR(bdev)) {
ret = PTR_ERR(bdev);
goto out;
}
set_blocksize(bdev, root->fs_info->sb->s_blocksize);
ret = btrfs_insert_dev_radix(root, bdev, device_id,
block_start, num_blocks);
BUG_ON(ret);
ret = 0;
out:
kfree(null_filename);
return ret;
}
static int read_device_info(struct btrfs_root *root)
{
struct btrfs_path *path;
int ret;
struct btrfs_key key;
struct btrfs_leaf *leaf;
struct btrfs_device_item *dev_item;
int nritems;
int slot;
root = root->fs_info->dev_root;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = 0;
key.offset = 0;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
mutex_lock(&root->fs_info->fs_mutex);
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
leaf = btrfs_buffer_leaf(path->nodes[0]);
nritems = btrfs_header_nritems(&leaf->header);
while(1) {
slot = path->slots[0];
if (slot >= nritems) {
ret = btrfs_next_leaf(root, path);
if (ret)
break;
leaf = btrfs_buffer_leaf(path->nodes[0]);
nritems = btrfs_header_nritems(&leaf->header);
slot = path->slots[0];
}
btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
if (btrfs_key_type(&key) != BTRFS_DEV_ITEM_KEY) {
path->slots[0]++;
continue;
}
dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_device_item);
printk("found key %Lu %Lu\n", key.objectid, key.offset);
if (btrfs_device_id(dev_item) !=
btrfs_super_device_id(root->fs_info->disk_super)) {
ret = btrfs_open_disk(root, btrfs_device_id(dev_item),
key.objectid, key.offset,
(char *)(dev_item + 1),
btrfs_device_pathlen(dev_item));
BUG_ON(ret);
}
path->slots[0]++;
}
btrfs_free_path(path);
mutex_unlock(&root->fs_info->fs_mutex);
return 0;
}
struct btrfs_root *open_ctree(struct super_block *sb)
{
struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
GFP_NOFS);
struct btrfs_root *dev_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;
struct dev_lookup *dev_lookup;
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);
INIT_RADIX_TREE(&fs_info->dev_radix, GFP_NOFS);
INIT_LIST_HEAD(&fs_info->trans_list);
sb_set_blocksize(sb, 4096);
fs_info->running_transaction = NULL;
fs_info->tree_root = tree_root;
fs_info->extent_root = extent_root;
fs_info->dev_root = dev_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, dev_root,
fs_info, BTRFS_DEV_TREE_OBJECTID);
__setup_root(sb->s_blocksize, tree_root,
fs_info, BTRFS_ROOT_TREE_OBJECTID);
dev_lookup = kmalloc(sizeof(*dev_lookup), GFP_NOFS);
dev_lookup->block_start = 0;
dev_lookup->num_blocks = (u32)-2;
dev_lookup->bdev = sb->s_bdev;
dev_lookup->device_id = 0;
ret = radix_tree_insert(&fs_info->dev_radix, (u32)-2, dev_lookup);
BUG_ON(ret);
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;
i_size_write(fs_info->btree_inode,
btrfs_super_total_blocks(disk_super) <<
fs_info->btree_inode->i_blkbits);
radix_tree_delete(&fs_info->dev_radix, (u32)-2);
dev_lookup->block_start = btrfs_super_device_block_start(disk_super);
dev_lookup->num_blocks = btrfs_super_device_num_blocks(disk_super);
dev_lookup->device_id = btrfs_super_device_id(disk_super);
ret = radix_tree_insert(&fs_info->dev_radix,
dev_lookup->block_start +
dev_lookup->num_blocks - 1, dev_lookup);
BUG_ON(ret);
fs_info->disk_super = disk_super;
dev_root->node = read_tree_block(tree_root,
btrfs_super_device_root(disk_super));
ret = read_device_info(dev_root);
BUG_ON(ret);
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,
bh_blocknr(root->fs_info->tree_root->node));
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;
}
static int free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
{
radix_tree_delete(&fs_info->fs_roots_radix,
(unsigned long)root->root_key.objectid);
if (root->inode)
iput(root->inode);
if (root->node)
brelse(root->node);
if (root->commit_root)
brelse(root->commit_root);
kfree(root);
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++)
free_fs_root(fs_info, gang[i]);
}
return 0;
}
static int free_dev_radix(struct btrfs_fs_info *fs_info)
{
struct dev_lookup *lookup[8];
struct block_device *super_bdev = fs_info->sb->s_bdev;
int ret;
int i;
while(1) {
ret = radix_tree_gang_lookup(&fs_info->dev_radix,
(void **)lookup, 0,
ARRAY_SIZE(lookup));
if (!ret)
break;
for (i = 0; i < ret; i++) {
if (lookup[i]->bdev != super_bdev)
close_bdev_excl(lookup[i]->bdev);
radix_tree_delete(&fs_info->dev_radix,
lookup[i]->block_start +
lookup[i]->num_blocks - 1);
kfree(lookup[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->dev_root->node)
btrfs_block_release(fs_info->dev_root,
fs_info->dev_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);
free_dev_radix(fs_info);
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);
}