// (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 {

	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 {

// 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

//
// 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

**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.**

				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
			}

	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 {