There are a couple of improvements to make to the lfs_migrate script:
- pass all of the "lfs setstripe" options through to "lfs migrate" when calling "lfs_migrate" (they do not overlap), so it would be possible to just strip out existing lfs_migrate options and pass the rest to "lfs migrate"
- the man page should be updated to say it is safe to use on in-use files for 2.5+ MDTs (when the lfs migrate command was in place and working correctly)
- the man page should be split into a separate lfs-migrate.1 man page with more description and examples (per LU-4315)
- the hard-link migration doesn't need to do anything special if "lfs migrate" works, and if it fails then "lfs path2fid" and "lfs fid2path" (or "lfs path2fid --parents") can be used to generate the list of links to a file and then hard-link