fc: Add support for noflush cache option

Firecracker supports noflush semantic via Unsafe cache type.
There is no support for direct i/o, remove it from config file

Fixes: #7823

Signed-off-by: Alexandru Matei <alexandru.matei@uipath.com>

src/runtime/virtcontainers/fc.go

@@ -835,6 +835,17 @@ func (fc *firecracker) createDiskPool(ctx context.Context) error {
 			PathOnHost:   &jailedDrive,
 		}
 
+		if fc.config.BlockDeviceCacheSet {
+			var cacheOption string
+			if fc.config.BlockDeviceCacheNoflush {
+				cacheOption = models.DriveCacheTypeUnsafe
+			} else {
+				cacheOption = models.DriveCacheTypeWriteback
+			}
+
+			drive.CacheType = &cacheOption
+		}
+
 		fc.fcConfig.Drives = append(fc.fcConfig.Drives, drive)
 	}