rbd: whitelist RBD_FEATURE_OPERATIONS feature bit

This feature bit restricts older clients from performing certain
maintenance operations against an image (e.g. clone, snap create).
krbd does not perform maintenance operations.

Cc: stable@vger.kernel.org
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

drivers/block/rbd.c

@@ -124,11 +124,13 @@ static int atomic_dec_return_safe(atomic_t *v)
 #define RBD_FEATURE_STRIPINGV2		(1ULL<<1)
 #define RBD_FEATURE_EXCLUSIVE_LOCK	(1ULL<<2)
 #define RBD_FEATURE_DATA_POOL		(1ULL<<7)
+#define RBD_FEATURE_OPERATIONS		(1ULL<<8)
 
 #define RBD_FEATURES_ALL	(RBD_FEATURE_LAYERING |		\
 				 RBD_FEATURE_STRIPINGV2 |	\
 				 RBD_FEATURE_EXCLUSIVE_LOCK |	\
-				 RBD_FEATURE_DATA_POOL)
+				 RBD_FEATURE_DATA_POOL |	\
+				 RBD_FEATURE_OPERATIONS)
 
 /* Features supported by this (client software) implementation. */