Re: [PATCH] tmpfs: ZERO_RANGE and COLLAPSE_RANGE not currently supported

["Lukáš Czerner" <lczerner@redhat.com>]

On Sun, 15 Jun 2014, Hugh Dickins wrote:

> Date: Sun, 15 Jun 2014 18:28:00 -0700 (PDT)
> From: Hugh Dickins <hughd@google.com>
> To: Andrew Morton <akpm@linux-foundation.org>
> Cc: Lukas Czerner <lczerner@redhat.com>,
>     Namjae Jeon <namjae.jeon@samsung.com>, linux-kernel@vger.kernel.org
> Subject: [PATCH] tmpfs: ZERO_RANGE and COLLAPSE_RANGE not currently supported
> 
> I was well aware of FALLOC_FL_ZERO_RANGE and FALLOC_FL_COLLAPSE_RANGE
> support being added to fallocate(); but didn't realize until now that
> I had been too stupid to future-proof shmem_fallocate() against new
> additions.  -EOPNOTSUPP instead of going on to ordinary fallocation.

Looks good.

Reviewed-by: Lukas Czerner <lczerner@redhat.com>

> 
> Signed-off-by: Hugh Dickins <hughd@google.com>
> Cc: stable@vger.kernel.org # v3.15
> ---
> 
>  mm/shmem.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> --- v3.15/mm/shmem.c	2014-06-08 11:19:54.000000000 -0700
> +++ linux/mm/shmem.c	2014-06-15 18:01:16.988996166 -0700
> @@ -1728,6 +1728,9 @@ static long shmem_fallocate(struct file
>  	pgoff_t start, index, end;
>  	int error;
>  
> +	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
> +		return -EOPNOTSUPP;
> +
>  	mutex_lock(&inode->i_mutex);
>  
>  	if (mode & FALLOC_FL_PUNCH_HOLE) {
>