github.com/olljanat/moby@v1.13.1/pkg/devicemapper/ioctl.go (about)

     1  // +build linux
     2  
     3  package devicemapper
     4  
     5  import (
     6  	"syscall"
     7  	"unsafe"
     8  )
     9  
    10  func ioctlBlkGetSize64(fd uintptr) (int64, error) {
    11  	var size int64
    12  	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, fd, BlkGetSize64, uintptr(unsafe.Pointer(&size))); err != 0 {
    13  		return 0, err
    14  	}
    15  	return size, nil
    16  }
    17  
    18  func ioctlBlkDiscard(fd uintptr, offset, length uint64) error {
    19  	var r [2]uint64
    20  	r[0] = offset
    21  	r[1] = length
    22  
    23  	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, fd, BlkDiscard, uintptr(unsafe.Pointer(&r[0]))); err != 0 {
    24  		return err
    25  	}
    26  	return nil
    27  }