read: more careful file size check, for read/pwrite
read: more careful file size check, for read/pwrite

bowlofstew/sv6,bowlofstew/sv6,bowlofstew/sv6,aclements/sv6,aclements/sv6,aclements/sv6,bowlofstew/sv6,bowlofstew/sv6,aclements/sv6,aclements/sv6