Comment 20 for bug 1776920

I have done some experiments and find out that
the behavior of lseek with whence set to SEEK_DATA is different from the behavior of Linux's lseek.

If the supplied offset is in the middle of a data region, it returns the start of the next data region. There may be many data regions in a big file even though it has no hole.

return value of lseek with whence set to SEEK_DATA:

|--(offset)--Data----|(return value)----Data----|
|--(offset)--Data----|----Hole----|(return value)----Data----|