mirror of
https://github.com/restic/restic.git
synced 2024-12-25 01:06:39 +00:00
33 lines
708 B
Go
33 lines
708 B
Go
package restorer
|
|
|
|
import (
|
|
"os"
|
|
"runtime"
|
|
"unsafe"
|
|
|
|
"golang.org/x/sys/unix"
|
|
)
|
|
|
|
func preallocateFile(wr *os.File, size int64) error {
|
|
// try contiguous first
|
|
fst := unix.Fstore_t{
|
|
Flags: unix.F_ALLOCATECONTIG | unix.F_ALLOCATEALL,
|
|
Posmode: unix.F_PEOFPOSMODE,
|
|
Offset: 0,
|
|
Length: size,
|
|
}
|
|
_, err := unix.FcntlInt(wr.Fd(), unix.F_PREALLOCATE, int(uintptr(unsafe.Pointer(&fst))))
|
|
|
|
if err == nil {
|
|
return nil
|
|
}
|
|
|
|
// just take preallocation in any form, but still ask for everything
|
|
fst.Flags = unix.F_ALLOCATEALL
|
|
_, err = unix.FcntlInt(wr.Fd(), unix.F_PREALLOCATE, int(uintptr(unsafe.Pointer(&fst))))
|
|
|
|
// Keep struct alive until fcntl has returned
|
|
runtime.KeepAlive(fst)
|
|
|
|
return err
|
|
}
|