linux-ext4 - Re: [PATCH v2] ext4: don't ignore return values from ext4_ext

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Message-ID: <20200423154640.GB28707@quack2.suse.cz>
Date:   Thu, 23 Apr 2020 17:46:40 +0200
From:   Jan Kara <jack@...e.cz>
To:     Harshad Shirwadkar <harshadshirwadkar@...il.com>
Cc:     linux-ext4@...r.kernel.org
Subject: Re: [PATCH v2] ext4: don't ignore return values from ext4_ext_dirty()

On Mon 20-04-20 20:02:47, Harshad Shirwadkar wrote:
> Don't ignore return values from ext4_ext_dirty, since the errors
> indicate valid failures below Ext4.  In all of the other instances of
> ext4_ext_dirty calls, the error return value is handled in some
> way. This patch makes those remaining couple of places to handle
> ext4_ext_dirty errors as well. In case of ext4_split_extent_at(), the
> ignorance of return value is intentional. The reason is that we are
> already in error path and there isn't much we can do if ext4_ext_dirty
> returns error. This patch adds a comment for that case explaining why
> we ignore the return value.
> 
> In the longer run, we probably should
> make sure that errors from other mark_dirty routines are handled as
> well.
> 
> Ran gce-xfstests smoke tests and verified that there were no
> regressions.
> 
> Changes since V1:
> Fixed incorrect return value handling in ext4_split_extent_at()

The 'Changes' part should go below the '---' separator. There's no need to
have it included in the final commit message.

> Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@...il.com>

Otherwise the patch looks good to me. You can add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/ext4/extents.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index f2b577b315a0..6425f4f9a197 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3244,6 +3244,10 @@ static int ext4_split_extent_at(handle_t *handle,
>  
>  fix_extent_len:
>  	ex->ee_len = orig_ex.ee_len;
> +	/*
> +	 * Ignore ext4_ext_dirty return value since we are already in error path
> +	 * and err is a non-zero error code.
> +	 */
>  	ext4_ext_dirty(handle, inode, path + path->p_depth);
>  	return err;
>  }
> @@ -3503,7 +3507,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
>  	}
>  	if (allocated) {
>  		/* Mark the block containing both extents as dirty */
> -		ext4_ext_dirty(handle, inode, path + depth);
> +		err = ext4_ext_dirty(handle, inode, path + depth);
>  
>  		/* Update path to point to the right extent */
>  		path[depth].p_ext = abut_ex;
> -- 
> 2.26.1.301.g55bc3eb7cb9-goog
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR