int (*sb_mount)(const char *dev_name, const struct path *path,
const char *type, unsigned long flags, void *data);
int (*sb_umount)(struct vfsmount *mnt, int flags);
int (*sb_mount)(const char *dev_name, const struct path *path,
const char *type, unsigned long flags, void *data);
int (*sb_umount)(struct vfsmount *mnt, int flags);