[RFC PATCH 1/2] fs: fix path_check_prereq()

[Sascha Hauer]

On Tue, Oct 18, 2011 at 01:48:44PM +0400, Antony Pavlov wrote:
> This patch makes impossible the situations than path_check_prereq() can make
> 'return 0' without changing errno.
> 
> Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
> ---
>  fs/fs.c |    7 ++++---
>  1 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/fs.c b/fs/fs.c
> index 7d65ec8..714fc9b 100644
> --- a/fs/fs.c
> +++ b/fs/fs.c
> @@ -293,9 +293,11 @@ static int path_check_prereq(const char *path, unsigned int flags)
>  	struct stat s;
>  	unsigned int m;
>  
> +	errno = 0;
> +
>  	if (stat(path, &s)) {
>  		if (flags & S_UB_DOES_NOT_EXIST)
> -			return 0;
> +			goto out;

Wow. You broke mkdir.

stat() changes errno, so path_check_prereq returns an error value
when S_UB_DOES_NOT_EXIST is set and a file does not exist.

Sascha

>  		errno = -ENOENT;
>  		goto out;
>  	}
> @@ -306,7 +308,7 @@ static int path_check_prereq(const char *path, unsigned int flags)
>  	}
>  
>  	if (flags == S_UB_EXISTS)
> -		return 0;
> +		goto out;
>  
>  	m = s.st_mode;
>  
> @@ -325,7 +327,6 @@ static int path_check_prereq(const char *path, unsigned int flags)
>  		goto out;
>  	}
>  
> -	errno = 0;
>  out:
>  	return errno;
>  }
> -- 
> 1.7.6.3
> 
> 
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> 

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