lseek with SEEK_HOLE and SEEK_DATA are really helpful and easy to use tools for any usersapce applications like copy and backup. Currently lustre has min support implementation as per the man page which is not that useful however lustre does support fiemap ioctl which can be used for mapping data in the file.
As we already have support for fiemap I guess with some implementation lustre can support SEEK_HOLE and SEEK_DATA flags. I guess having this support will be helpful to deal with sparse files. Any feedback about the implementation will be really helpful.