/*
* this is used to update the root pointer in the tree of tree roots.
*
* But, in the case of the extent allocation tree, updating the root
* pointer may allocate blocks which may change the root of the extent
* allocation tree.
*
* So, this loops and repeats and makes sure the cowonly root didn't
* change while the root pointer was being updated in the metadata.
*/
static int update_cowonly_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret;
u64 old_root_bytenr;
struct btrfs_root *tree_root = root->fs_info->tree_root;
btrfs_write_dirty_block_groups(trans, root);
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
BUG_ON(ret);
while (1) {
old_root_bytenr = btrfs_root_bytenr(&root->root_item);
if (old_root_bytenr == root->node->start)
break;
btrfs_set_root_bytenr(&root->root_item,
root->node->start);
btrfs_set_root_level(&root->root_item,
btrfs_header_level(root->node));
btrfs_set_root_generation(&root->root_item, trans->transid);
ret = btrfs_update_root(trans, tree_root,
&root->root_key,
&root->root_item);
BUG_ON(ret);
btrfs_write_dirty_block_groups(trans, root);
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
BUG_ON(ret);
}
return 0;
}
/*
* update all the cowonly tree roots on disk
*/
static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct list_head *next;
struct extent_buffer *eb;
int ret;
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
BUG_ON(ret);
eb = btrfs_lock_root_node(fs_info->tree_root);
btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
BUG_ON(ret);
while (!list_empty(&fs_info->dirty_cowonly_roots)) {
next = fs_info->dirty_cowonly_roots.next;
list_del_init(next);
root = list_entry(next, struct btrfs_root, dirty_list);
update_cowonly_root(trans, root);
}
down_write(&fs_info->extent_commit_sem);
switch_commit_root(fs_info->extent_root);
up_write(&fs_info->extent_commit_sem);
return 0;
}
static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int throttle)
{
struct btrfs_transaction *cur_trans = trans->transaction;
struct btrfs_fs_info *info = root->fs_info;
int count = 0;
while (count < 4) {
unsigned long cur = trans->delayed_ref_updates;
trans->delayed_ref_updates = 0;
if (cur &&
trans->transaction->delayed_refs.num_heads_ready > 64) {
trans->delayed_ref_updates = 0;
/*
* do a full flush if the transaction is trying
* to close
*/
if (trans->transaction->delayed_refs.flushing)
cur = 0;
btrfs_run_delayed_refs(trans, root, cur);
} else {
break;
}
count++;
}
btrfs_trans_release_metadata(trans, root);
if (!root->fs_info->open_ioctl_trans &&
should_end_transaction(trans, root))
trans->transaction->blocked = 1;
if (cur_trans->blocked && !cur_trans->in_commit) {
if (throttle)
return btrfs_commit_transaction(trans, root);
else
wake_up_process(info->transaction_kthread);
}
mutex_lock(&info->trans_mutex);
WARN_ON(cur_trans != info->running_transaction);
WARN_ON(cur_trans->num_writers < 1);
cur_trans->num_writers--;
if (waitqueue_active(&cur_trans->writer_wait))
wake_up(&cur_trans->writer_wait);
put_transaction(cur_trans);
mutex_unlock(&info->trans_mutex);
if (current->journal_info == trans)
current->journal_info = NULL;
memset(trans, 0, sizeof(*trans));
kmem_cache_free(btrfs_trans_handle_cachep, trans);
if (throttle)
btrfs_run_delayed_iputs(root);
return 0;
}
int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_transaction *cur_trans = trans->transaction;
int updates;
if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
return 1;
updates = trans->delayed_ref_updates;
trans->delayed_ref_updates = 0;
if (updates)
btrfs_run_delayed_refs(trans, root, updates);
return should_end_transaction(trans, root);
}
static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int throttle)
{
struct btrfs_transaction *cur_trans;
struct btrfs_fs_info *info = root->fs_info;
int count = 0;
while (count < 4) {
unsigned long cur = trans->delayed_ref_updates;
trans->delayed_ref_updates = 0;
if (cur &&
trans->transaction->delayed_refs.num_heads_ready > 64) {
trans->delayed_ref_updates = 0;
/*
* do a full flush if the transaction is trying
* to close
*/
if (trans->transaction->delayed_refs.flushing)
cur = 0;
btrfs_run_delayed_refs(trans, root, cur);
} else {
break;
}
count++;
}
mutex_lock(&info->trans_mutex);
cur_trans = info->running_transaction;
WARN_ON(cur_trans != trans->transaction);
WARN_ON(cur_trans->num_writers < 1);
cur_trans->num_writers--;
if (waitqueue_active(&cur_trans->writer_wait))
wake_up(&cur_trans->writer_wait);
put_transaction(cur_trans);
mutex_unlock(&info->trans_mutex);
if (current->journal_info == trans)
current->journal_info = NULL;
memset(trans, 0, sizeof(*trans));
kmem_cache_free(btrfs_trans_handle_cachep, trans);
return 0;
}
int commit_tree_roots(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info)
{
struct btrfs_root *root;
struct list_head *next;
struct extent_buffer *eb;
int ret;
if (fs_info->readonly)
return 0;
eb = fs_info->tree_root->node;
extent_buffer_get(eb);
ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
free_extent_buffer(eb);
if (ret)
return ret;
/*
* If the above CoW is the first one to dirty the current tree_root,
* delayed refs for it won't be run until after this function has
* finished executing, meaning we won't process the extent tree root,
* which will have been added to ->dirty_cowonly_roots. So run
* delayed refs here as well.
*/
ret = btrfs_run_delayed_refs(trans, -1);
if (ret)
return ret;
while(!list_empty(&fs_info->dirty_cowonly_roots)) {
next = fs_info->dirty_cowonly_roots.next;
list_del_init(next);
root = list_entry(next, struct btrfs_root, dirty_list);
ret = update_cowonly_root(trans, root);
free_extent_buffer(root->commit_root);
root->commit_root = NULL;
if (ret < 0)
return ret;
}
return 0;
}
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
u64 transid = trans->transid;
int ret = 0;
struct btrfs_fs_info *fs_info = root->fs_info;
if (trans->fs_info->transaction_aborted)
return -EROFS;
/*
* Flush all accumulated delayed refs so that root-tree updates are
* consistent
*/
ret = btrfs_run_delayed_refs(trans, -1);
if (ret < 0)
goto error;
if (root->commit_root == root->node)
goto commit_tree;
if (root == root->fs_info->tree_root)
goto commit_tree;
if (root == root->fs_info->chunk_root)
goto commit_tree;
free_extent_buffer(root->commit_root);
root->commit_root = NULL;
btrfs_set_root_bytenr(&root->root_item, root->node->start);
btrfs_set_root_generation(&root->root_item, trans->transid);
root->root_item.level = btrfs_header_level(root->node);
ret = btrfs_update_root(trans, root->fs_info->tree_root,
&root->root_key, &root->root_item);
if (ret < 0)
goto error;
commit_tree:
ret = commit_tree_roots(trans, fs_info);
if (ret < 0)
goto error;
/*
* Ensure that all committed roots are properly accounted in the
* extent tree
*/
ret = btrfs_run_delayed_refs(trans, -1);
if (ret < 0)
goto error;
btrfs_write_dirty_block_groups(trans);
__commit_transaction(trans, root);
if (ret < 0)
goto error;
ret = write_ctree_super(trans);
btrfs_finish_extent_commit(trans);
kfree(trans);
free_extent_buffer(root->commit_root);
root->commit_root = NULL;
fs_info->running_transaction = NULL;
fs_info->last_trans_committed = transid;
return ret;
error:
btrfs_destroy_delayed_refs(trans);
free(trans);
return ret;
}
