Re: [PATCH v2] btrfs: remove unnecessary error check

[Eric Sandeen <esandeen@redhat.com>]

On 7/10/14, 1:44 AM, Satoru Takeuchi wrote:
> (2014/07/10 12:26), Eric Sandeen wrote:
>>
>>
>>> On Jul 9, 2014, at 10:20 PM, Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com> wrote:
>>>
>>> From: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
>>>
>>> If "(!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC))" is false,
>>> obviously "trans" is -ENOSPC. So we can safely remove the redundant
>>> "(PTR_ERR(trans) == -ENOSPC)" check.
>>>
>>
>> True, but now a comment like:
>>
>> /* Handle ENOSPC */
>>
>> might still be nice...
> 
> Eric, thank you for your comment. I fixed my patch.
> How about is it?

One other thing I missed the first time, I'm sorry, notes below:

> 
> ===
> From: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
> 
> If "(!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC))" is false,
> obviously "trans" is -ENOSPC. So we can safely remove the redundant
> "(PTR_ERR(trans) == -ENOSPC)" check.
> 
> Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
> 
> ---
>  fs/btrfs/inode.c | 29 +++++++++++++++--------------
>  1 file changed, 15 insertions(+), 14 deletions(-)
> 
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 3668048..115aac3 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -3803,22 +3803,23 @@ static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
>      if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
>          return trans;
>  
> -    if (PTR_ERR(trans) == -ENOSPC) {
> -        u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
> +    /* Handle ENOSPC */
>  
> -        trans = btrfs_start_transaction(root, 0);
> -        if (IS_ERR(trans))
> -            return trans;
> -        ret = btrfs_cond_migrate_bytes(root->fs_info,
> -                           &root->fs_info->trans_block_rsv,
> -                           num_bytes, 5);
> -        if (ret) {
> -            btrfs_end_transaction(trans, root);
> -            return ERR_PTR(ret);
> -        }
> -        trans->block_rsv = &root->fs_info->trans_block_rsv;
> -        trans->bytes_reserved = num_bytes;
> +    u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);

This variable should be declared at the beginning of the function,
not in the middle, because it's no longer in a separate code block.

Also, somehow by the time the patch got here, tabs turned into
4 spaces, so this one wouldn't apply for me.

Sorry for missing the variable declaration problem the first time!

-Eric

> +
> +    trans = btrfs_start_transaction(root, 0);
> +    if (IS_ERR(trans))
> +        return trans;
> +    ret = btrfs_cond_migrate_bytes(root->fs_info,
> +                       &root->fs_info->trans_block_rsv,
> +                       num_bytes, 5);
> +    if (ret) {
> +        btrfs_end_transaction(trans, root);
> +        return ERR_PTR(ret);
>      }
> +    trans->block_rsv = &root->fs_info->trans_block_rsv;
> +    trans->bytes_reserved = num_bytes;
> +
>      return trans;
>  }
>