SEEK_DATA and SEEK_HOLE are whences for lseek(2) supported by Linux since version 3.1.
These are useful to deal with sparse files.
I propose that ruby supports these whences.
This issue was solved with changeset r42211.
Masaki, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.
io.c (interpret_seek_whence): support SEEK_DATA and SEEK_HOLE.
These are whences for lseek(2) supported by Linux since version 3.1. [ruby-core:56123] [Feature #8671]