orangefs: add features op

This is a new userspace operation, which will be done if the client-core
version is greater than or equal to 2.9.6. This will provide a way to
implement optional features and to determine which features are
supported by the client-core. If the client-core version is older than
2.9.6, no optional features are supported and the op will not be done.

The intent is to allow protocol extensions without relying on the
client-core's current behavior of ignoring what it doesn't understand.

Signed-off-by: Martin Brandenburg <martin@omnibond.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/orangefs/downcall.h b/fs/orangefs/downcall.h
index db6e8722a89e..3b8923f8bf21 100644
--- a/fs/orangefs/downcall.h
+++ b/fs/orangefs/downcall.h
@@ -101,6 +101,11 @@ struct orangefs_fs_key_response {
 	char fs_key[FS_KEY_BUF_SIZE];
 };
 
+/* 2.9.6 */
+struct orangefs_features_response {
+	__u64 features;
+};
+
 struct orangefs_downcall_s {
 	__s32 type;
 	__s32 status;
@@ -122,6 +127,7 @@ struct orangefs_downcall_s {
 		struct orangefs_param_response param;
 		struct orangefs_perf_count_response perf_count;
 		struct orangefs_fs_key_response fs_key;
+		struct orangefs_features_response features;
 	} resp;
 };