Re: [PATCH] Grow: fix resize of array component size to > 32bits

[NeilBrown <neilb@suse.de>]

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On Fri, 24 Oct 2014 17:55:02 -0700 Justin Maggard <jmaggard10@gmail.com>
wrote:

> If the request --size to --grow an array to is larger
> than 32bits, then mdadm may make the wrong choice and
> use ioctl instead of setting component_size via sysfs
> and the change is ignored.

Can you explain exactly why the  current code is not sufficient?  When does
it fail?
If you include the explanation in a re-submission of the patch, and I am
convinced, then I will gladly apply your patch.

Thanks,
NeilBrown

> 
> Instead of using casts to check for a 32-bit overflow,
> just check for set bits outside of INT32_MAX.
> ---
>  Grow.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/Grow.c b/Grow.c
> index a9c8589..a614102 100644
> --- a/Grow.c
> +++ b/Grow.c
> @@ -1818,7 +1818,7 @@ int Grow_reshape(char *devname, int fd,
>  		if (s->size == MAX_SIZE)
>  			s->size = 0;
>  		array.size = s->size;
> -		if (array.size != (signed)s->size) {
> +		if (s->size & ~INT32_MAX) {
>  			/* got truncated to 32bit, write to
>  			 * component_size instead
>  			 */


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