ceph: track primary dentry link

Newer versions of the MDS will flag a dentry as "primary". In later
patches, we'll need to consult this info, so track it in di->flags.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

include/linux/ceph/ceph_fs.h

@@ -531,6 +531,9 @@ struct ceph_mds_reply_lease {
 	__le32 seq;
 } __attribute__ ((packed));
 
+#define CEPH_LEASE_VALID        (1 | 2) /* old and new bit values */
+#define CEPH_LEASE_PRIMARY_LINK 4       /* primary linkage */
+
 struct ceph_mds_reply_dirfrag {
 	__le32 frag;            /* fragment */
 	__le32 auth;            /* auth mds, if this is a delegation point */