libceph: ceph_can_shift_osds(pool) and pool type defines

Bring in pg_pool_t::can_shift_osds() counterpart along with pool type
defines.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>

include/linux/ceph/osdmap.h

@@ -41,6 +41,18 @@ struct ceph_pg_pool_info {
 	char *name;
 };
 
+static inline bool ceph_can_shift_osds(struct ceph_pg_pool_info *pool)
+{
+	switch (pool->type) {
+	case CEPH_POOL_TYPE_REP:
+		return true;
+	case CEPH_POOL_TYPE_EC:
+		return false;
+	default:
+		BUG_ON(1);
+	}
+}
+
 struct ceph_object_locator {
 	s64 pool;
 };

include/linux/ceph/rados.h

@@ -81,8 +81,9 @@ struct ceph_pg_v1 {
  */
 #define CEPH_NOPOOL  ((__u64) (-1))  /* pool id not defined */
 
-#define CEPH_PG_TYPE_REP     1
-#define CEPH_PG_TYPE_RAID4   2
+#define CEPH_POOL_TYPE_REP     1
+#define CEPH_POOL_TYPE_RAID4   2 /* never implemented */
+#define CEPH_POOL_TYPE_EC      3
 
 /*
  * stable_mod func is used to control number of placement groups.