When the send protocol versioning was added in 5.16 
e77fbf990316
("btrfs: send: prepare for v2 protocol"), the 32/64bit compat code was
not updated (added by 
2351f431f727 ("btrfs: fix send ioctl on 32bit with
64bit kernel")), missing the version struct member. The compat code is
probably rarely used, nobody reported any bugs.
Found by tool https://github.com/jirislaby/clang-struct .
Fixes: e77fbf990316 ("btrfs: send: prepare for v2 protocol")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
 
                arg->clone_sources = compat_ptr(args32.clone_sources);
                arg->parent_root = args32.parent_root;
                arg->flags = args32.flags;
+               arg->version = args32.version;
                memcpy(arg->reserved, args32.reserved,
                       sizeof(args32.reserved));
 #else