ceph: use kill_anon_super helper

ceph open-codes this around some other activity and the rationale
for it isn't clear. There is no need to delay free_anon_bdev until
the end of kill_sb.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/super.c

@@ -1205,14 +1205,13 @@ static int ceph_init_fs_context(struct fs_context *fc)
 static void ceph_kill_sb(struct super_block *s)
 {
 	struct ceph_fs_client *fsc = ceph_sb_to_client(s);
-	dev_t dev = s->s_dev;
 
 	dout("kill_sb %p\n", s);
 
 	ceph_mdsc_pre_umount(fsc->mdsc);
 	flush_fs_workqueues(fsc);
 
-	generic_shutdown_super(s);
+	kill_anon_super(s);
 
 	fsc->client->extra_mon_dispatch = NULL;
 	ceph_fs_debugfs_cleanup(fsc);
@@ -1220,7 +1219,6 @@ static void ceph_kill_sb(struct super_block *s)
 	ceph_fscache_unregister_fs(fsc);
 
 	destroy_fs_client(fsc);
-	free_anon_bdev(dev);
 }
 
 static struct file_system_type ceph_fs_type = {