Re: [PATCH] overlayfs: Do d_type check only if work dir creation was successful

[Carlos Maiolino <cmaiolino@redhat.com>]

Hi Vivek.

On Fri, May 20, 2016 at 09:04:26AM -0400, Vivek Goyal wrote:
> d_type check requires successful creation of workdir as iterates
> through work dir and expects work dir to be present in it. If that's
> not the case, this check will always return d_type not supported even
> if underlying filesystem might be supporting it.
>

ovl_check_d_type_supported, will call iterate_dir(), which is supposed to return
-ENOENT if the work dir is not present AFAICT, isn't that enough to detect if
work dir is present and handle it accordingly?

I recently started to learn overlay code, so my apologies if my above comment is
not true.

Cheers

> So don't do this check if work dir creation failed in previous step.
> 
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> ---
>  fs/overlayfs/super.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index 791235e..48234425 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -1064,16 +1064,19 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
>  		/*
>  		 * Upper should support d_type, else whiteouts are visible.
>  		 * Given workdir and upper are on same fs, we can do
> -		 * iterate_dir() on workdir.
> +		 * iterate_dir() on workdir. This check requires successful
> +		 * creation of workdir in previous step.
>  		 */
> -		err = ovl_check_d_type_supported(&workpath);
> -		if (err < 0)
> -			goto out_put_workdir;
> +		if (ufs->workdir) {
> +			err = ovl_check_d_type_supported(&workpath);
> +			if (err < 0)
> +				goto out_put_workdir;
>  
> -		if (!err) {
> -			pr_err("overlayfs: upper fs needs to support d_type.\n");
> -			err = -EINVAL;
> -			goto out_put_workdir;
> +			if (!err) {
> +				pr_err("overlayfs: upper fs needs to support d_type.\n");
> +				err = -EINVAL;
> +				goto out_put_workdir;
> +			}
>  		}
>  	}
>  
> -- 
> 2.7.4
> 
> --
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-- 
Carlos