Re: [PATCH 1/2] btrfs: Make btrfs_async_run_delayed_root use a loop rather than multiple labels

[Qu Wenruo <wqu@suse.com>]

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On 2017年10月23日 18:51, Nikolay Borisov wrote:
> Currently btrfs_async_run_delayed_root's implementation uses 3 goto labels to
> mimic the functionality of a simple do {} while loop. Refactor the function
> to use a do {} while construct, making intention clear and code easier to
> follow. No functional changes
> 
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>

Looks good to me.

Reviewed-by: Qu Wenruo <wqu@suse.com>
> ---
>  fs/btrfs/delayed-inode.c | 52 +++++++++++++++++++++++++-----------------------
>  1 file changed, 27 insertions(+), 25 deletions(-)
> 
> diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
> index 19e4ad2f3f2e..1bfdb90d7633 100644
> --- a/fs/btrfs/delayed-inode.c
> +++ b/fs/btrfs/delayed-inode.c
> @@ -1323,40 +1323,42 @@ static void btrfs_async_run_delayed_root(struct btrfs_work *work)
>  	if (!path)
>  		goto out;
>  
> -again:
> -	if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND / 2)
> -		goto free_path;
> +	do {
> +		if (atomic_read(&delayed_root->items) <
> +		    BTRFS_DELAYED_BACKGROUND / 2)
> +			break;
>  
> -	delayed_node = btrfs_first_prepared_delayed_node(delayed_root);
> -	if (!delayed_node)
> -		goto free_path;
> +		delayed_node = btrfs_first_prepared_delayed_node(delayed_root);
> +		if (!delayed_node)
> +			break;
>  
> -	path->leave_spinning = 1;
> -	root = delayed_node->root;
> +		path->leave_spinning = 1;
> +		root = delayed_node->root;
>  
> -	trans = btrfs_join_transaction(root);
> -	if (IS_ERR(trans))
> -		goto release_path;
> +		trans = btrfs_join_transaction(root);
> +		if (IS_ERR(trans)) {
> +			btrfs_release_path(path);
> +			btrfs_release_prepared_delayed_node(delayed_node);
> +			total_done++;
> +			continue;
> +		}
>  
> -	block_rsv = trans->block_rsv;
> -	trans->block_rsv = &root->fs_info->delayed_block_rsv;
> +		block_rsv = trans->block_rsv;
> +		trans->block_rsv = &root->fs_info->delayed_block_rsv;
>  
> -	__btrfs_commit_inode_delayed_items(trans, path, delayed_node);
> +		__btrfs_commit_inode_delayed_items(trans, path, delayed_node);
>  
> -	trans->block_rsv = block_rsv;
> -	btrfs_end_transaction(trans);
> -	btrfs_btree_balance_dirty_nodelay(root->fs_info);
> +		trans->block_rsv = block_rsv;
> +		btrfs_end_transaction(trans);
> +		btrfs_btree_balance_dirty_nodelay(root->fs_info);
>  
> -release_path:
> -	btrfs_release_path(path);
> -	total_done++;
> +		btrfs_release_path(path);
> +		btrfs_release_prepared_delayed_node(delayed_node);
> +		total_done++;
>  
> -	btrfs_release_prepared_delayed_node(delayed_node);
> -	if ((async_work->nr == 0 && total_done < BTRFS_DELAYED_WRITEBACK) ||
> -	    total_done < async_work->nr)
> -		goto again;
> +	} while ((async_work->nr == 0 && total_done < BTRFS_DELAYED_WRITEBACK)
> +		 || total_done < async_work->nr);
>  
> -free_path:
>  	btrfs_free_path(path);
>  out:
>  	wake_up(&delayed_root->wait);
> 


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