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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;
extern struct kmem_cache *btrfs_trans_handle_cachep;
extern struct kmem_cache *btrfs_transaction_cachep;
#define BTRFS_ROOT_TRANS_TAG 0
#define TRANS_MAGIC 0xE1E10E
static void put_transaction(struct btrfs_transaction *transaction)
{
WARN_ON(transaction->use_count == 0);
transaction->use_count--;
WARN_ON(transaction->magic != TRANS_MAGIC);
if (transaction->use_count == 0) {
WARN_ON(total_trans == 0);
total_trans--;
memset(transaction, 0, sizeof(*transaction));
kmem_cache_free(btrfs_transaction_cachep, 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 = kmem_cache_alloc(btrfs_transaction_cachep,
GFP_NOFS);
total_trans++;
BUG_ON(!cur_trans);
root->fs_info->generation++;
root->fs_info->running_transaction = cur_trans;
cur_trans->num_writers = 0;
cur_trans->transid = root->fs_info->generation;
init_waitqueue_head(&cur_trans->writer_wait);
init_waitqueue_head(&cur_trans->commit_wait);
cur_trans->magic = TRANS_MAGIC;
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 =
kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
int ret;
u64 running_trans_id;
mutex_lock(&root->fs_info->trans_mutex);
ret = join_transaction(root);
BUG_ON(ret);
running_trans_id = root->fs_info->running_transaction->transid;
if (root != root->fs_info->tree_root && root->last_trans <
running_trans_id) {
radix_tree_tag_set(&root->fs_info->fs_roots_radix,
(unsigned long)root, BTRFS_ROOT_TRANS_TAG);
root->commit_root = root->node;
get_bh(root->node);
}
root->last_trans = running_trans_id;
h->transid = running_trans_id;
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);
h->magic = h->magic2 = TRANS_MAGIC;
return h;
}
int btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_transaction *cur_trans;
WARN_ON(trans->magic != TRANS_MAGIC);
WARN_ON(trans->magic2 != TRANS_MAGIC);
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));
kmem_cache_free(btrfs_trans_handle_cachep, 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;
}
struct dirty_root {
struct list_head list;
struct btrfs_key snap_key;
struct buffer_head *commit_root;
struct btrfs_root *root;
};
int add_dirty_roots(struct btrfs_trans_handle *trans,
struct radix_tree_root *radix, struct list_head *list)
{
struct dirty_root *dirty;
struct btrfs_root *gang[8];
struct btrfs_root *root;
int i;
int ret;
int err;
printk("add dirty\n");
while(1) {
ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
ARRAY_SIZE(gang),
BTRFS_ROOT_TRANS_TAG);
if (ret == 0)
break;
for (i = 0; i < ret; i++) {
root = gang[i];
radix_tree_tag_clear(radix, (unsigned long)root,
BTRFS_ROOT_TRANS_TAG);
if (root->commit_root == root->node) {
WARN_ON(root->node->b_blocknr !=
btrfs_root_blocknr(&root->root_item));
brelse(root->commit_root);
root->commit_root = NULL;
continue;
}
dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
BUG_ON(!dirty);
memcpy(&dirty->snap_key, &root->root_key,
sizeof(root->root_key));
dirty->commit_root = root->commit_root;
root->commit_root = NULL;
dirty->root = root;
printk("adding dirty root %Lu gen %Lu blocknr %Lu\n", root->root_key.objectid, root->root_key.offset, dirty->commit_root->b_blocknr);
root->root_key.offset = root->fs_info->generation;
btrfs_set_root_blocknr(&root->root_item,
root->node->b_blocknr);
err = btrfs_insert_root(trans, root->fs_info->tree_root,
&root->root_key,
&root->root_item);
BUG_ON(err);
list_add(&dirty->list, list);
}
}
printk("add dirty done\n");
return 0;
}
int drop_dirty_roots(struct btrfs_root *tree_root, struct list_head *list)
{
struct dirty_root *dirty;
struct btrfs_trans_handle *trans;
int ret;
while(!list_empty(list)) {
dirty = list_entry(list->next, struct dirty_root, list);
list_del_init(&dirty->list);
trans = btrfs_start_transaction(tree_root, 1);
printk("drop snapshot root %p, commit_root blocknr %Lu generation %Lu\n", dirty->root, dirty->commit_root->b_blocknr, dirty->snap_key.offset);
ret = btrfs_drop_snapshot(trans, dirty->root,
dirty->commit_root);
BUG_ON(ret);
printk("del root objectid %Lu, offset %Lu\n", dirty->snap_key.objectid, dirty->snap_key.offset);
ret = btrfs_del_root(trans, tree_root, &dirty->snap_key);
BUG_ON(ret);
ret = btrfs_end_transaction(trans, tree_root);
BUG_ON(ret);
kfree(dirty);
}
return 0;
}
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret = 0;
struct btrfs_transaction *cur_trans;
struct list_head dirty_fs_roots;
DEFINE_WAIT(wait);
INIT_LIST_HEAD(&dirty_fs_roots);
mutex_lock(&root->fs_info->trans_mutex);
if (trans->transaction->in_commit) {
printk("already in commit!, waiting\n");
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;
}
cur_trans = trans->transaction;
trans->transaction->in_commit = 1;
while (trans->transaction->num_writers > 1) {
WARN_ON(cur_trans != trans->transaction);
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);
}
finish_wait(&trans->transaction->writer_wait, &wait);
WARN_ON(cur_trans != trans->transaction);
add_dirty_roots(trans, &root->fs_info->fs_roots_radix, &dirty_fs_roots);
ret = btrfs_commit_tree_roots(trans, root);
BUG_ON(ret);
cur_trans = root->fs_info->running_transaction;
root->fs_info->running_transaction = NULL;
btrfs_set_super_generation(root->fs_info->disk_super,
root->fs_info->generation + 1);
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);
cur_trans->commit_done = 1;
wake_up(&cur_trans->commit_wait);
put_transaction(cur_trans);
put_transaction(cur_trans);
mutex_unlock(&root->fs_info->trans_mutex);
kmem_cache_free(btrfs_trans_handle_cachep, trans);
drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
return ret;
}
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