ceph: check availability of mds cluster on mount

Signed-off-by: Yan, Zheng <zyan@redhat.com>
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index b382e59..537f966 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -137,6 +137,8 @@
 	Opt_nofscache,
 	Opt_poolperm,
 	Opt_nopoolperm,
+	Opt_require_active_mds,
+	Opt_norequire_active_mds,
 #ifdef CONFIG_CEPH_FS_POSIX_ACL
 	Opt_acl,
 #endif
@@ -171,6 +173,8 @@
 	{Opt_nofscache, "nofsc"},
 	{Opt_poolperm, "poolperm"},
 	{Opt_nopoolperm, "nopoolperm"},
+	{Opt_require_active_mds, "require_active_mds"},
+	{Opt_norequire_active_mds, "norequire_active_mds"},
 #ifdef CONFIG_CEPH_FS_POSIX_ACL
 	{Opt_acl, "acl"},
 #endif
@@ -287,6 +291,12 @@
 	case Opt_nopoolperm:
 		fsopt->flags |= CEPH_MOUNT_OPT_NOPOOLPERM;
 		break;
+	case Opt_require_active_mds:
+		fsopt->flags &= ~CEPH_MOUNT_OPT_MOUNTWAIT;
+		break;
+	case Opt_norequire_active_mds:
+		fsopt->flags |= CEPH_MOUNT_OPT_MOUNTWAIT;
+		break;
 #ifdef CONFIG_CEPH_FS_POSIX_ACL
 	case Opt_acl:
 		fsopt->sb_flags |= MS_POSIXACL;