generic: ensure we drop suid after fallocate

fallocate changes file contents, so make sure that we drop privileges
and file capabilities after each fallocate operation.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>
12 files changed