Re: [ndctl PATCH v2] ndctl: print 'size' when creating/listing BTT namespaces

[Linda Knippers <linda.knippers@hpe.com>]

On 07/27/2016 06:39 PM, Vishal Verma wrote:
> Print the usable size of a BTT namespace after removing driver overhead
> in the json for listing/creating a BTT namespace. This makes it
> consistent with other flavors of namespaces (dax, pfn).

Thanks, this works for me.  I also tried it on a kernel without the btt
patch that exposes the size to confirm that it does no harm with older kernels.

-- ljk
> 
> Cc: Dan Williams <dan.j.williams@intel.com>
> Reported-by: Linda Knippers <linda.knippers@hpe.com>
> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
> ---
> 
> v2:
> - For a create-namespace command, size was not shown as expected, and as
>   it did for 'ndctl list'. This was because after creating the namespace,
>   the 'size' field in the existing list of BTTs in libndctl needed to be
>   updated with the new value found in sysfs. Add this missing update.
> 
>  ndctl/lib/libndctl.c   | 14 ++++++++++++++
>  ndctl/lib/libndctl.sym |  1 +
>  ndctl/libndctl.h.in    |  1 +
>  ndctl/util/json.c      |  1 +
>  4 files changed, 17 insertions(+)
> 
> diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c
> index 0722f79..8ad62c6 100644
> --- a/ndctl/lib/libndctl.c
> +++ b/ndctl/lib/libndctl.c
> @@ -271,6 +271,7 @@ struct ndctl_namespace {
>   * struct ndctl_btt - stacked block device provided sector atomicity
>   * @module: kernel module (nd_btt)
>   * @lbasize: sector size info
> + * @size: usable size of the btt after removing metadata etc
>   * @ndns: host namespace for the btt instance
>   * @region: parent region
>   * @btt_path: btt devpath
> @@ -284,6 +285,7 @@ struct ndctl_btt {
>  	struct ndctl_namespace *ndns;
>  	struct list_node list;
>  	struct ndctl_lbasize lbasize;
> +	unsigned long long size;
>  	char *btt_path;
>  	char *btt_buf;
>  	char *bdev;
> @@ -3614,9 +3616,16 @@ static int add_btt(void *parent, int id, const char *btt_base)
>  	if (parse_lbasize_supported(ctx, devname, buf, &btt->lbasize) < 0)
>  		goto err_read;
>  
> +	sprintf(path, "%s/size", btt_base);
> +	if (sysfs_read_attr(ctx, path, buf) < 0)
> +		btt->size = ULLONG_MAX;
> +	else
> +		btt->size = strtoull(buf, NULL, 0);
> +
>  	free(path);
>  	ndctl_btt_foreach(region, btt_dup)
>  		if (btt->id == btt_dup->id) {
> +			btt_dup->size = btt->size;
>  			free_btt(btt, NULL);
>  			return 1;
>  		}
> @@ -3705,6 +3714,11 @@ NDCTL_EXPORT void ndctl_btt_get_uuid(struct ndctl_btt *btt, uuid_t uu)
>  	memcpy(uu, btt->uuid, sizeof(uuid_t));
>  }
>  
> +NDCTL_EXPORT unsigned long long ndctl_btt_get_size(struct ndctl_btt *btt)
> +{
> +	return btt->size;
> +}
> +
>  NDCTL_EXPORT int ndctl_btt_set_uuid(struct ndctl_btt *btt, uuid_t uu)
>  {
>  	struct ndctl_ctx *ctx = ndctl_btt_get_ctx(btt);
> diff --git a/ndctl/lib/libndctl.sym b/ndctl/lib/libndctl.sym
> index 6af267a..b5d2866 100644
> --- a/ndctl/lib/libndctl.sym
> +++ b/ndctl/lib/libndctl.sym
> @@ -196,6 +196,7 @@ global:
>  	ndctl_btt_get_num_sector_sizes;
>  	ndctl_btt_get_namespace;
>  	ndctl_btt_get_uuid;
> +	ndctl_btt_get_size;
>  	ndctl_btt_is_enabled;
>  	ndctl_btt_is_valid;
>  	ndctl_btt_get_devname;
> diff --git a/ndctl/libndctl.h.in b/ndctl/libndctl.h.in
> index 9e0e82a..451466a 100644
> --- a/ndctl/libndctl.h.in
> +++ b/ndctl/libndctl.h.in
> @@ -521,6 +521,7 @@ unsigned int ndctl_btt_get_sector_size(struct ndctl_btt *btt);
>  int ndctl_btt_get_num_sector_sizes(struct ndctl_btt *btt);
>  struct ndctl_namespace *ndctl_btt_get_namespace(struct ndctl_btt *btt);
>  void ndctl_btt_get_uuid(struct ndctl_btt *btt, uuid_t uu);
> +unsigned long long ndctl_btt_get_size(struct ndctl_btt *btt);
>  int ndctl_btt_is_enabled(struct ndctl_btt *btt);
>  int ndctl_btt_is_valid(struct ndctl_btt *btt);
>  const char *ndctl_btt_get_devname(struct ndctl_btt *btt);
> diff --git a/ndctl/util/json.c b/ndctl/util/json.c
> index a9c096c..c727bc2 100644
> --- a/ndctl/util/json.c
> +++ b/ndctl/util/json.c
> @@ -174,6 +174,7 @@ struct json_object *util_namespace_to_json(struct ndctl_namespace *ndns)
>  		break;
>  	case NDCTL_NS_MODE_SAFE:
>  		jobj = json_object_new_string("sector");
> +		size = ndctl_btt_get_size(btt);
>  		break;
>  	case NDCTL_NS_MODE_RAW:
>  		size = ndctl_namespace_get_size(ndns);
> 

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