linux-kernel - Re: [PATCH 5/5] btrfs: Use common error handling code in btrfs_mark_extent

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Date:   Mon, 21 Aug 2017 09:07:00 -0400
From:   Jeff Mahoney <jeffm@...e.com>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>,
        linux-btrfs@...r.kernel.org, Chris Mason <clm@...com>,
        David Sterba <dsterba@...e.com>, Josef Bacik <jbacik@...com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH 5/5] btrfs: Use common error handling code in
 btrfs_mark_extent_written()

On 8/21/17 8:42 AM, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Mon, 21 Aug 2017 14:15:23 +0200
> 
> Add jump targets so that a bit of exception handling can be better reused
> at the end of this function.
> 
> This issue was detected by using the Coccinelle software.

btrfs_abort_transaction dumps __FILE__:__LINE__ in the log so this patch
makes the code more difficult to debug.

-Jeff

> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  fs/btrfs/file.c | 62 ++++++++++++++++++++++-----------------------------------
>  1 file changed, 24 insertions(+), 38 deletions(-)
> 
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index 74fd7756cff3..675683051cbc 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -1122,25 +1122,17 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
>  
>  	leaf = path->nodes[0];
>  	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
> -	if (key.objectid != ino ||
> -	    key.type != BTRFS_EXTENT_DATA_KEY) {
> -		ret = -EINVAL;
> -		btrfs_abort_transaction(trans, ret);
> -		goto out;
> -	}
> +	if (key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY)
> +		goto e_inval;
> +
>  	fi = btrfs_item_ptr(leaf, path->slots[0],
>  			    struct btrfs_file_extent_item);
> -	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC) {
> -		ret = -EINVAL;
> -		btrfs_abort_transaction(trans, ret);
> -		goto out;
> -	}
> +	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC)
> +		goto e_inval;
> +
>  	extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
> -	if (key.offset > start || extent_end < end) {
> -		ret = -EINVAL;
> -		btrfs_abort_transaction(trans, ret);
> -		goto out;
> -	}
> +	if (key.offset > start || extent_end < end)
> +		goto e_inval;
>  
>  	bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
>  	num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
> @@ -1213,10 +1205,8 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
>  			btrfs_release_path(path);
>  			goto again;
>  		}
> -		if (ret < 0) {
> -			btrfs_abort_transaction(trans, ret);
> -			goto out;
> -		}
> +		if (ret < 0)
> +			goto abort_transaction;
>  
>  		leaf = path->nodes[0];
>  		fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
> @@ -1237,18 +1227,15 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
>  		ret = btrfs_inc_extent_ref(trans, fs_info, bytenr, num_bytes,
>  					   0, root->root_key.objectid,
>  					   ino, orig_offset);
> -		if (ret) {
> -			btrfs_abort_transaction(trans, ret);
> -			goto out;
> -		}
> +		if (ret)
> +			goto abort_transaction;
>  
>  		if (split == start) {
>  			key.offset = start;
>  		} else {
>  			if (start != key.offset) {
>  				ret = -EINVAL;
> -				btrfs_abort_transaction(trans, ret);
> -				goto out;
> +				goto abort_transaction;
>  			}
>  			path->slots[0]--;
>  			extent_end = end;
> @@ -1271,10 +1258,8 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
>  		ret = btrfs_free_extent(trans, fs_info, bytenr, num_bytes,
>  					0, root->root_key.objectid,
>  					ino, orig_offset);
> -		if (ret) {
> -			btrfs_abort_transaction(trans, ret);
> -			goto out;
> -		}
> +		if (ret)
> +			goto abort_transaction;
>  	}
>  	other_start = 0;
>  	other_end = start;
> @@ -1291,10 +1276,8 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
>  		ret = btrfs_free_extent(trans, fs_info, bytenr, num_bytes,
>  					0, root->root_key.objectid,
>  					ino, orig_offset);
> -		if (ret) {
> -			btrfs_abort_transaction(trans, ret);
> -			goto out;
> -		}
> +		if (ret)
> +			goto abort_transaction;
>  	}
>  	if (del_nr == 0) {
>  		fi = btrfs_item_ptr(leaf, path->slots[0],
> @@ -1314,14 +1297,17 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
>  		btrfs_mark_buffer_dirty(leaf);
>  
>  		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
> -		if (ret < 0) {
> -			btrfs_abort_transaction(trans, ret);
> -			goto out;
> -		}
> +		if (ret < 0)
> +			goto abort_transaction;
>  	}
>  out:
>  	btrfs_free_path(path);
>  	return 0;
> +e_inval:
> +	ret = -EINVAL;
> +abort_transaction:
> +	btrfs_abort_transaction(trans, ret);
> +	goto out;
>  }
>  
>  /*
> 


-- 
Jeff Mahoney
SUSE Labs



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