[ndctl PATCH v3 2/2] ndctl: add sector_size to 'ndctl list' output

[Ross Zwisler <ross.zwisler@linux.intel.com>]

It used to be that the only PMEM namespaces with a variable sector size
were ones with a BTT, but that has changed.  sector_size still doesn't make
sense for device DAX since we don't have a block I/O path.

If we don't have a specified sector size, as happens with namespaces of
devtype nd_namespace_io and older v1.1 namespace labels, we will display
the default sector size of 512.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
---
 util/json.c | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/util/json.c b/util/json.c
index 95beaa2..17d8f13 100644
--- a/util/json.c
+++ b/util/json.c
@@ -718,11 +718,6 @@ struct json_object *util_namespace_to_json(struct ndctl_namespace *ndns,
 			goto err;
 		json_object_object_add(jndns, "uuid", jobj);
 
-		jobj = json_object_new_int(ndctl_btt_get_sector_size(btt));
-		if (!jobj)
-			goto err;
-		json_object_object_add(jndns, "sector_size", jobj);
-
 		bdev = ndctl_btt_get_block_device(btt);
 	} else if (pfn) {
 		ndctl_pfn_get_uuid(pfn, uuid);
@@ -774,6 +769,30 @@ struct json_object *util_namespace_to_json(struct ndctl_namespace *ndns,
 	} else
 		bdev = ndctl_namespace_get_block_device(ndns);
 
+	jobj = NULL;
+	if (btt) {
+		jobj = json_object_new_int(ndctl_btt_get_sector_size(btt));
+		if (!jobj)
+			goto err;
+	} else if (!dax) {
+		unsigned int sector_size = ndctl_namespace_get_sector_size(ndns);
+
+		/*
+		 * The kernel will default to a 512 byte sector size on PMEM
+		 * namespaces that don't explicitly have a sector size. This
+		 * happens because they use pre-v1.2 labels or because they
+		 * don't have a label space (devtype=nd_namespace_io).
+		 */
+		if (!sector_size)
+			sector_size = 512;
+
+		jobj = json_object_new_int(sector_size);
+		if (!jobj)
+			goto err;
+	}
+	if (jobj)
+		json_object_object_add(jndns, "sector_size", jobj);
+
 	if (bdev && bdev[0]) {
 		jobj = json_object_new_string(bdev);
 		if (!jobj)
-- 
2.14.3

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