glibc2 defines struct dirent differently than the Linux kernel does.
The getdents function therefore needs to read a heuristically defined
number of kernel dirents to satisfy the request. In case where too
many kernel dirents have been read, the function lseeks on the
directory so that a next call will start with the right dirent. The
offset used in lseeking is the offset-field in the last dirent passed
to the application. This can only mean that the offset-field holds
the offset of the next dirent and not the offset of the dirent itself.