MNT_SNAPSHOT
#define MOPT_SNAPSHOT { "snapshot", 0, MNT_SNAPSHOT, 0 }
MNT_SNAPSHOT | MNT_ROOTFS | MNT_UPDATEMASK | MNT_RDONLY);
MNT_SNAPSHOT);
MNT_FLAG(MNT_SNAPSHOT);
{ MNT_SNAPSHOT, "snapshot" }, \
MNT_FORCE | MNT_SNAPSHOT | MNT_NONBUSY | \
mntorflags |= MNT_SNAPSHOT;
if (mp->mnt_flag & MNT_SNAPSHOT) {