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#include <linux/module.h>
#include <linux/fs.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
static int total_trans = 0;
static void put_transaction(struct btrfs_transaction *transaction)
{
transaction->use_count--;
if (transaction->use_count == 0) {
WARN_ON(total_trans == 0);
total_trans--;
kfree(transaction);
}
}
static int join_transaction(struct btrfs_root *root)
{
struct btrfs_transaction *cur_trans;
cur_trans = root->fs_info->running_transaction;
if (!cur_trans) {
cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
total_trans++;
BUG_ON(!cur_trans);
root->fs_info->running_transaction = cur_trans;
cur_trans->num_writers = 0;
cur_trans->transid = root->root_key.offset + 1;
init_waitqueue_head(&cur_trans->writer_wait);
init_waitqueue_head(&cur_trans->commit_wait);
cur_trans->in_commit = 0;
cur_trans->use_count = 1;
cur_trans->commit_done = 0;
}
cur_trans->num_writers++;
return 0;
}
struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
int num_blocks)
{
struct btrfs_trans_handle *h = kmalloc(sizeof(*h), GFP_NOFS);
int ret;
mutex_lock(&root->fs_info->trans_mutex);
ret = join_transaction(root);
BUG_ON(ret);
h->transid = root->fs_info->running_transaction->transid;
h->transaction = root->fs_info->running_transaction;
h->blocks_reserved = num_blocks;
h->blocks_used = 0;
root->fs_info->running_transaction->use_count++;
mutex_unlock(&root->fs_info->trans_mutex);
return h;
}
int btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_transaction *cur_trans;
mutex_lock(&root->fs_info->trans_mutex);
cur_trans = root->fs_info->running_transaction;
WARN_ON(cur_trans->num_writers < 1);
if (waitqueue_active(&cur_trans->writer_wait))
wake_up(&cur_trans->writer_wait);
cur_trans->num_writers--;
put_transaction(cur_trans);
mutex_unlock(&root->fs_info->trans_mutex);
memset(trans, 0, sizeof(*trans));
kfree(trans);
return 0;
}
int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
filemap_write_and_wait(root->fs_info->btree_inode->i_mapping);
return 0;
}
int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret;
u64 old_extent_block;
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root *extent_root = fs_info->extent_root;
struct btrfs_root *inode_root = fs_info->inode_root;
btrfs_set_root_blocknr(&inode_root->root_item,
inode_root->node->b_blocknr);
ret = btrfs_update_root(trans, tree_root,
&inode_root->root_key,
&inode_root->root_item);
BUG_ON(ret);
while(1) {
old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
if (old_extent_block == extent_root->node->b_blocknr)
break;
btrfs_set_root_blocknr(&extent_root->root_item,
extent_root->node->b_blocknr);
ret = btrfs_update_root(trans, tree_root,
&extent_root->root_key,
&extent_root->root_item);
BUG_ON(ret);
}
return 0;
}
static int wait_for_commit(struct btrfs_root *root,
struct btrfs_transaction *commit)
{
DEFINE_WAIT(wait);
while(!commit->commit_done) {
prepare_to_wait(&commit->commit_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (commit->commit_done)
break;
mutex_unlock(&root->fs_info->trans_mutex);
schedule();
mutex_lock(&root->fs_info->trans_mutex);
}
finish_wait(&commit->commit_wait, &wait);
return 0;
}
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret = 0;
struct buffer_head *snap;
struct btrfs_key snap_key;
struct btrfs_transaction *cur_trans;
DEFINE_WAIT(wait);
mutex_lock(&root->fs_info->trans_mutex);
if (trans->transaction->in_commit) {
cur_trans = trans->transaction;
trans->transaction->use_count++;
btrfs_end_transaction(trans, root);
ret = wait_for_commit(root, cur_trans);
BUG_ON(ret);
put_transaction(cur_trans);
mutex_unlock(&root->fs_info->trans_mutex);
return 0;
}
while (trans->transaction->num_writers > 1) {
prepare_to_wait(&trans->transaction->writer_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (trans->transaction->num_writers <= 1)
break;
mutex_unlock(&root->fs_info->trans_mutex);
schedule();
mutex_lock(&root->fs_info->trans_mutex);
}
finish_wait(&trans->transaction->writer_wait, &wait);
if (root->node != root->commit_root) {
memcpy(&snap_key, &root->root_key, sizeof(snap_key));
root->root_key.offset++;
}
if (btrfs_root_blocknr(&root->root_item) != root->node->b_blocknr) {
btrfs_set_root_blocknr(&root->root_item, root->node->b_blocknr);
ret = btrfs_insert_root(trans, root->fs_info->tree_root,
&root->root_key, &root->root_item);
BUG_ON(ret);
}
ret = btrfs_commit_tree_roots(trans, root);
BUG_ON(ret);
cur_trans = root->fs_info->running_transaction;
root->fs_info->running_transaction = NULL;
mutex_unlock(&root->fs_info->trans_mutex);
ret = btrfs_write_and_wait_transaction(trans, root);
BUG_ON(ret);
write_ctree_super(trans, root);
btrfs_finish_extent_commit(trans, root);
mutex_lock(&root->fs_info->trans_mutex);
put_transaction(cur_trans);
put_transaction(cur_trans);
mutex_unlock(&root->fs_info->trans_mutex);
kfree(trans);
if (root->node != root->commit_root) {
trans = btrfs_start_transaction(root, 1);
snap = root->commit_root;
root->commit_root = root->node;
get_bh(root->node);
ret = btrfs_drop_snapshot(trans, root, snap);
BUG_ON(ret);
ret = btrfs_del_root(trans, root->fs_info->tree_root,
&snap_key);
BUG_ON(ret);
root->fs_info->generation = root->root_key.offset + 1;
ret = btrfs_end_transaction(trans, root);
BUG_ON(ret);
}
return ret;
}
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