linux-ext4 - Re: [PATCH] ext4: drop an always true check

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Date:   Wed, 17 Nov 2021 13:26:13 -0700
From:   Andreas Dilger <adilger@...ger.ca>
To:     Adam Borowski <kilobyte@...band.pl>
Cc:     Theodore Ts'o <tytso@....edu>,
        linux-ext4 <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH] ext4: drop an always true check

On Nov 15, 2021, at 10:20 AM, Adam Borowski <kilobyte@...band.pl> wrote:
> 
> EXT_FIRST_INDEX(ptr) is ptr+12, which can't possibly be null; gcc-12
> warns about this.
> 
> Signed-off-by: Adam Borowski <kilobyte@...band.pl>

I was wondering if this was intending to check if path[depth].p_hdr was NULL,
but it is clear from the rest of the code that this could not be true, since
it is already being accessed earlier in the code, so this looks fine.

Reviewed-by: Andreas Dilger <adilger@...ger.ca>

> ---
> fs/ext4/extents.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 0ecf819bf189..5aa279742da9 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -1496,8 +1496,7 @@ static int ext4_ext_search_left(struct inode *inode,
> 				EXT4_ERROR_INODE(inode,
> 				  "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
> 				  ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
> -				  EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
> -		le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
> +				  le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block),
> 				  depth);
> 				return -EFSCORRUPTED;
> 			}
> --
> 2.33.1
> 


Cheers, Andreas






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