+/*
+ * Different pointer width leads to structure size change. Kernel should accept
+ * both ioctl values (derived from the structures) for backward compatibility.
+ * Size of this structure is same on 32bit and 64bit though.
+ *
+ * NOTE: do not use in your code, this is for testing only
+ */
+struct btrfs_ioctl_send_args_64 {
+ __s64 send_fd; /* in */
+ __u64 clone_sources_count; /* in */
+ union {
+ __u64 __user *clone_sources; /* in */
+ __u64 __clone_sources_alignment;
+ };
+ __u64 parent_root; /* in */
+ __u64 flags; /* in */
+ __u64 reserved[4]; /* in */
+} __attribute__((packed));
+BUILD_ASSERT(sizeof(struct btrfs_ioctl_send_args_64) == 72);
+
+#define BTRFS_IOC_SEND_64_COMPAT_DEFINED 1
+