btrfs_record_unlink_dir() is an important operation that affects inode logging and is called during unlink and rename operations. Add a trace event for it to help debug issues. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>