[parted-devel] [PATCH 06/11] libparted: respect optimal IO alignment

[Jim Meyering]

Phillip Susi wrote:
> If the optimal IO size provided by the kernel was less than 1 MiB
> or not an even power of two, parted ignored it and used 1 MiB
> instead.  Values less than 1 MiB or not an even power of two are
> common with raid arrays, so respect the kernel supplied value.
> Regular disks will still use 1 MiB since the kernel returns a
> value of zero.

Hi Phillip,

I would like to continue using the existing guards or similar
when operating on regular disks.  Can you adjust this change to
remove the guards only when the device is a raid array?

...
> +++ b/libparted/arch/linux.c
> @@ -2977,16 +2977,7 @@ linux_get_optimum_alignment(const PedDevice *dev)
>             If one or the other will not divide evenly, fall through to
>             previous logic. */
>          unsigned long optimal_io = blkid_topology_get_optimal_io_size(tp);
> -        unsigned long minimum_io = blkid_topology_get_minimum_io_size(tp);
> -        if (
> -            (!optimal_io && !minimum_io)
> -	    || (optimal_io && PED_DEFAULT_ALIGNMENT % optimal_io == 0
> -		&& minimum_io && PED_DEFAULT_ALIGNMENT % minimum_io == 0)
> -	    || (!minimum_io && optimal_io
> -		&& PED_DEFAULT_ALIGNMENT % optimal_io == 0)
> -	    || (!optimal_io && minimum_io
> -		&& PED_DEFAULT_ALIGNMENT % minimum_io == 0)
> -           ) {
> +	if (!optimal_io) {
...