v4.19.13 snapshot.
diff --git a/include/linux/ceph/debugfs.h b/include/linux/ceph/debugfs.h
new file mode 100644
index 0000000..fa5f9b7
--- /dev/null
+++ b/include/linux/ceph/debugfs.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _FS_CEPH_DEBUGFS_H
+#define _FS_CEPH_DEBUGFS_H
+
+#include <linux/ceph/ceph_debug.h>
+#include <linux/ceph/types.h>
+
+#define CEPH_DEFINE_SHOW_FUNC(name) \
+static int name##_open(struct inode *inode, struct file *file) \
+{ \
+ return single_open(file, name, inode->i_private); \
+} \
+ \
+static const struct file_operations name##_fops = { \
+ .open = name##_open, \
+ .read = seq_read, \
+ .llseek = seq_lseek, \
+ .release = single_release, \
+};
+
+/* debugfs.c */
+extern int ceph_debugfs_init(void);
+extern void ceph_debugfs_cleanup(void);
+extern int ceph_debugfs_client_init(struct ceph_client *client);
+extern void ceph_debugfs_client_cleanup(struct ceph_client *client);
+
+#endif
+