Re: [RFC][PATCH 03/13] do_fchownat(): import pathname only once

On Sun 09-11-25 06:37:35, Al Viro wrote:
> Convert the user_path_at() call inside a retry loop into getname_flags() +
> filename_lookup() + putname() and leave only filename_lookup() inside
> the loop.
> 
> Since we have the default logics for use of LOOKUP_EMPTY (passed iff
> AT_EMPTY_PATH is present in flags), just use getname_uflags() and
> don't bother with setting LOOKUP_EMPTY in lookup_flags - getname_uflags()
> will pass the right thing to getname_flags() and filename_lookup()
> doesn't care about LOOKUP_EMPTY at all.
> 
> The things could be further simplified by use of cleanup.h stuff, but
> let's not clutter the patch with that.
> 
> Signed-off-by: Al Viro <[email protected]>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <[email protected]>

								Honza

> ---
>  fs/open.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/open.c b/fs/open.c
> index e9a08a820e49..e5110f5e80c7 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -804,17 +804,17 @@ int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
>  		int flag)
>  {
>  	struct path path;
> -	int error = -EINVAL;
> +	int error;
>  	int lookup_flags;
> +	struct filename *name;
>  
>  	if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
> -		goto out;
> +		return -EINVAL;
>  
>  	lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
> -	if (flag & AT_EMPTY_PATH)
> -		lookup_flags |= LOOKUP_EMPTY;
> +	name = getname_uflags(filename, flag);
>  retry:
> -	error = user_path_at(dfd, filename, lookup_flags, &path);
> +	error = filename_lookup(dfd, name, lookup_flags, &path, NULL);
>  	if (error)
>  		goto out;
>  	error = mnt_want_write(path.mnt);
> @@ -829,6 +829,7 @@ int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
>  		goto retry;
>  	}
>  out:
> +	putname(name);
>  	return error;
>  }
>  
> -- 
> 2.47.3
> 
-- 
Jan Kara <[email protected]>
SUSE Labs, CR