Re: [ndctl PATCH] test, libndctl: check btt size

[Vishal Verma <vishal.l.verma@intel.com>]

On 08/25, Dan Williams wrote:
> Now that the kernel reports the size of the btt, lets check that the
> size stays constant across kernel updates.  I.e. if we inadvertently
> introduce a change that causes the btt to reduce the effective capacity
> of the block device, this test is meant to catch it.
> 
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  test/libndctl.c |   66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 66 insertions(+)
> 
Good idea!
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>

> diff --git a/test/libndctl.c b/test/libndctl.c
> index 5f86addc5c7e..e36fe8a4fe6f 100644
> --- a/test/libndctl.c
> +++ b/test/libndctl.c
> @@ -937,6 +937,68 @@ static int check_pfn_create(struct ndctl_region *region,
>  	return rc;
>  }
>  
> +static int check_btt_size(struct ndctl_btt *btt)
> +{
> +	struct ndctl_namespace *ndns = ndctl_btt_get_namespace(btt);
> +	unsigned long long ns_size = ndctl_namespace_get_size(ndns);
> +	unsigned long sect_size = ndctl_btt_get_sector_size(btt);
> +	unsigned long long actual, expect;
> +	int size_select, sect_select;
> +	unsigned long long expect_table[][2] = {
> +		[0] = {
> +			[0] = 0x11b4400,
> +			[1] = 0x8da2000,
> +		},
> +		[1] = {
> +			[0] = 0x13b0400,
> +			[1] = 0x9d82000,
> +		},
> +		[2] = {
> +			[0] = 0x1aa2600,
> +			[1] = 0xd513000,
> +		},
> +	};
> +
> +	if (sect_size >= SZ_4K)
> +		sect_select = 1;
> +	else if (sect_size >= 512)
> +		sect_select = 0;
> +	else {
> +		fprintf(stderr, "%s: %s unexpected sector size: %lx\n",
> +				__func__, ndctl_btt_get_devname(btt),
> +				sect_size);
> +		return -ENXIO;
> +	}
> +
> +	switch (ns_size) {
> +	case SZ_18M:
> +		size_select = 0;
> +		break;
> +	case SZ_20M:
> +		size_select = 1;
> +		break;
> +	case SZ_27M:
> +		size_select = 2;
> +		break;
> +	default:
> +		fprintf(stderr, "%s: %s unexpected namespace size: %llx\n",
> +				__func__, ndctl_namespace_get_devname(ndns),
> +				ns_size);
> +		break;
> +	}
> +
> +	expect = expect_table[size_select][sect_select];
> +	actual = ndctl_btt_get_size(btt);
> +	if (expect != actual) {
> +		fprintf(stderr, "%s: namespace: %s unexpected size: %llx (expected: %llx)\n",
> +				ndctl_btt_get_devname(btt),
> +				ndctl_namespace_get_devname(ndns), actual, expect);
> +		return -ENXIO;
> +	}
> +
> +	return 0;
> +}
> +
>  static int check_btt_create(struct ndctl_region *region, struct ndctl_namespace *ndns,
>  		struct namespace *namespace)
>  {
> @@ -982,6 +1044,10 @@ static int check_btt_create(struct ndctl_region *region, struct ndctl_namespace
>  			fprintf(stderr, "%s: expected safe mode got: %d\n",
>  					devname, mode);
>  
> +		rc = check_btt_size(btt);
> +		if (rc)
> +			goto err;
> +
>  		if (btt_seed == ndctl_region_get_btt_seed(region)
>  				&& btt == btt_seed) {
>  			fprintf(stderr, "%s: failed to advance btt seed\n",
> 
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