rclone/lib/file/preallocate_windows.go
Nick Craig-Wood e43b5ce5e5 Remove github.com/pkg/errors and replace with std library version
This is possible now that we no longer support go1.12 and brings
rclone into line with standard practices in the Go world.

This also removes errors.New and errors.Errorf from lib/errors and
prefers the stdlib errors package over lib/errors.
2021-11-07 11:53:30 +00:00

111 lines
2.8 KiB
Go

//go:build windows
// +build windows
package file
import (
"fmt"
"os"
"sync"
"syscall"
"unsafe"
"golang.org/x/sys/windows"
)
var (
ntdll = windows.NewLazySystemDLL("ntdll.dll")
ntQueryVolumeInformationFile = ntdll.NewProc("NtQueryVolumeInformationFile")
ntSetInformationFile = ntdll.NewProc("NtSetInformationFile")
preAllocateMu sync.Mutex
)
type fileAllocationInformation struct {
AllocationSize uint64
}
type fileFsSizeInformation struct {
TotalAllocationUnits uint64
AvailableAllocationUnits uint64
SectorsPerAllocationUnit uint32
BytesPerSector uint32
}
type ioStatusBlock struct {
Status, Information uintptr
}
// PreallocateImplemented is a constant indicating whether the
// implementation of Preallocate actually does anything.
const PreallocateImplemented = true
// PreAllocate the file for performance reasons
func PreAllocate(size int64, out *os.File) error {
if size <= 0 {
return nil
}
preAllocateMu.Lock()
defer preAllocateMu.Unlock()
var (
iosb ioStatusBlock
fsSizeInfo fileFsSizeInformation
allocInfo fileAllocationInformation
)
// Query info about the block sizes on the file system
_, _, e1 := ntQueryVolumeInformationFile.Call(
uintptr(out.Fd()),
uintptr(unsafe.Pointer(&iosb)),
uintptr(unsafe.Pointer(&fsSizeInfo)),
uintptr(unsafe.Sizeof(fsSizeInfo)),
uintptr(3), // FileFsSizeInformation
)
if e1 != nil && e1 != syscall.Errno(0) {
return fmt.Errorf("preAllocate NtQueryVolumeInformationFile failed: %w", e1)
}
// Calculate the allocation size
clusterSize := uint64(fsSizeInfo.BytesPerSector) * uint64(fsSizeInfo.SectorsPerAllocationUnit)
if clusterSize <= 0 {
return fmt.Errorf("preAllocate clusterSize %d <= 0", clusterSize)
}
allocInfo.AllocationSize = (1 + uint64(size-1)/clusterSize) * clusterSize
// Ask for the allocation
_, _, e1 = ntSetInformationFile.Call(
uintptr(out.Fd()),
uintptr(unsafe.Pointer(&iosb)),
uintptr(unsafe.Pointer(&allocInfo)),
uintptr(unsafe.Sizeof(allocInfo)),
uintptr(19), // FileAllocationInformation
)
if e1 != nil && e1 != syscall.Errno(0) {
if e1 == syscall.Errno(windows.ERROR_DISK_FULL) || e1 == syscall.Errno(windows.ERROR_HANDLE_DISK_FULL) {
return ErrDiskFull
}
return fmt.Errorf("preAllocate NtSetInformationFile failed: %w", e1)
}
return nil
}
const (
FSCTL_SET_SPARSE = 0x000900c4
)
// SetSparseImplemented is a constant indicating whether the
// implementation of SetSparse actually does anything.
const SetSparseImplemented = true
// SetSparse makes the file be a sparse file
func SetSparse(out *os.File) error {
var bytesReturned uint32
err := syscall.DeviceIoControl(syscall.Handle(out.Fd()), FSCTL_SET_SPARSE, nil, 0, nil, 0, &bytesReturned, nil)
if err != nil {
return fmt.Errorf("DeviceIoControl FSCTL_SET_SPARSE: %w", err)
}
return nil
}