etcd/pkg/fs/fs.go
2014-04-09 10:15:28 -07:00

62 lines
1.4 KiB
Go

package fs
import (
"os"
"runtime"
"syscall"
"unsafe"
"github.com/coreos/etcd/log"
)
const (
// from Linux/include/uapi/linux/magic.h
BTRFS_SUPER_MAGIC = 0x9123683E
// from Linux/include/uapi/linux/fs.h
FS_NOCOW_FL = 0x00800000
FS_IOC_GETFLAGS = 0x80086601
FS_IOC_SETFLAGS = 0x40086602
)
// IsBtrfs checks whether the file is in btrfs
func IsBtrfs(path string) bool {
// btrfs is linux-only filesystem
// exit on other platforms
if runtime.GOOS != "linux" {
return false
}
var buf syscall.Statfs_t
if err := syscall.Statfs(path, &buf); err != nil {
log.Warnf("Failed to statfs: %v", err)
return false
}
log.Debugf("The type of path %v is %v", path, buf.Type)
if buf.Type != BTRFS_SUPER_MAGIC {
return false
}
log.Infof("The path %v is in btrfs", path)
return true
}
// SetNOCOW sets NOCOW flag for the file
func SetNOCOW(path string) {
file, err := os.Open(path)
if err != nil {
log.Warnf("Failed to open %v: %v", path, err)
return
}
defer file.Close()
var attr int
if _, _, errno := syscall.Syscall(syscall.SYS_IOCTL, file.Fd(), FS_IOC_GETFLAGS, uintptr(unsafe.Pointer(&attr))); errno != 0 {
log.Warnf("Failed to get file flags: %v", errno.Error())
return
}
attr |= FS_NOCOW_FL
if _, _, errno := syscall.Syscall(syscall.SYS_IOCTL, file.Fd(), FS_IOC_SETFLAGS, uintptr(unsafe.Pointer(&attr))); errno != 0 {
log.Warnf("Failed to set file flags: %v", errno.Error())
return
}
log.Infof("Set NOCOW to path %v succeeded", path)
}