//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package disk

import (
	"os"
)

// Fdatasync is a no-op
func Fdatasync(f *os.File) error {
	return nil
}

// FadviseDontNeed is a no-op
func FadviseDontNeed(f *os.File) error {
	return nil

// (st_size, as made by say ftruncate(2)), would require a metadata flush.
//
// The aim of fdatasync() is to reduce disk activity for applications that
// do not require all metadata to be synchronized with the disk.
func Fdatasync(f *os.File) error {
	return syscall.Fdatasync(int(f.Fd()))
}

// FadviseDontNeed invalidates page-cache
func FadviseDontNeed(f *os.File) error {

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package disk

import (
	"os"
	"syscall"
)

// Fdatasync is fsync on freebsd/darwin
func Fdatasync(f *os.File) error {
	return syscall.Fsync(int(f.Fd()))
}

// FadviseDontNeed is a no-op
func FadviseDontNeed(f *os.File) error {
	return nil

	defer updateOSMetrics(osMetricCreate, name)(err)
	return os.Create(name)
}

// Fdatasync captures time taken to call Fdatasync
func Fdatasync(f *os.File) (err error) {
	fn := ""
	if f != nil {
		fn = f.Name()
	}
	defer updateOSMetrics(osMetricFdatasync, fn)(err)
	return disk.Fdatasync(f)
}

// report returns all os metrics.
func (o *osMetrics) report() madmin.OSMetrics {

	b, err := je.MarshalMsg(nil)
	if err != nil {
		return err
	}

	jd.Lock()
	defer jd.Unlock()
	_, err = jd.file.Write(b)
	if err != nil {
		// Do not leak fd here, close the file properly.
		Fdatasync(jd.file)
		_ = jd.file.Close()

		jd.file = nil // reset to allow subsequent reopen when file/disk is available.
	}
	return err
}

				n, err = w.Write(buf[:len(buf)-remain])
				if err != nil {
					return written, err
				}
				nw = int64(n)
			}

			// Disable O_DIRECT on fd's on unaligned buffer
			// perform an amortized Fdatasync(fd) on the fd at
			// the end, this is performed by the caller before
			// closing 'w'.
			if err = disk.DisableDirectIO(file); err != nil {
				return written, err
			}

		return err
	}

	flags := os.O_CREATE | os.O_WRONLY | os.O_TRUNC

	var w *os.File
	if sync {
		// Perform DirectIO along with fdatasync for larger xl.meta, mostly when
		// xl.meta has "inlined data" we prefer writing O_DIRECT and then doing
		// fdatasync() at the end instead of opening the file with O_DSYNC.
		//
		// This is an optimization mainly to ensure faster I/O.
		if len(b) > xioutil.DirectioAlignSize {

**In our tests we also found ext4 does not honor POSIX O_DIRECT/Fdatasync semantics, ext4 trades performance for consistency guarantees. Please avoid ext4 in your setup.**

pkg syscall (netbsd-arm64-cgo), const SYS_FCNTL = 92
pkg syscall (netbsd-arm64-cgo), const SYS_FCNTL ideal-int
pkg syscall (netbsd-arm64-cgo), const SYS_FDATASYNC = 241
pkg syscall (netbsd-arm64-cgo), const SYS_FDATASYNC ideal-int
pkg syscall (netbsd-arm64-cgo), const SYS_FEXECVE = 465
pkg syscall (netbsd-arm64-cgo), const SYS_FEXECVE ideal-int
pkg syscall (netbsd-arm64-cgo), const SYS_FGETXATTR = 380

pkg syscall (freebsd-riscv64), const SYS_FCNTL = 92 #53466
pkg syscall (freebsd-riscv64), const SYS_FCNTL ideal-int #53466
pkg syscall (freebsd-riscv64), const SYS_FDATASYNC = 550 #53466
pkg syscall (freebsd-riscv64), const SYS_FDATASYNC ideal-int #53466
pkg syscall (freebsd-riscv64), const SYS_FEXECVE = 492 #53466
pkg syscall (freebsd-riscv64), const SYS_FEXECVE ideal-int #53466