[Yaffs] can't mount empty partition

I am trying to mount an empty partition as yaffs2 and can't mount it.

# mount -t yaffs2 /dev/mtdb-ctrl /mnt/
mount: mounting /dev/mtdb-ctrl on /mnt/ failed: Not a directory

>From dmesg,
[42949409.200000] yaffs: dev is 32505858 name is "mtdblock2"
[42949409.200000] yaffs: passed flags ""
[42949409.200000] yaffs_read_super: Using yaffs2
[42949409.200000] yaffs_read_super: block size 4096
[42949409.200000] yaffs: Attempting MTD mount on 31.2, "mtdblock2"
[42949409.200000] erase c0ad33d4
[42949409.200000] read c0ad37d4
[42949409.200000] write c0ad30ec
[42949409.200000] readoob c0ad3704
[42949409.200000] writeoob c0ad325c
[42949409.200000] block_isbad c0ad3614
[42949409.200000] block_markbad c0ad3678
[42949409.200000] writesize 2048
[42949409.200000] oobsize 64
[42949409.200000] erasesize 131072
[42949409.200000] size 220200960
[42949409.200000] yaffs locking
[42949409.720000] block 1677 is bad
[42949409.720000] block 1678 is bad
[42949409.720000] block 1679 is bad
[42949409.720000] block 1680 is bad
[42949409.730000] yaffs_read_super: guts initialised OK
[42949409.730000] yaffs unlocking
[42949409.730000] yaffs_get_inode for object 1
[42949409.730000] yaffs_read_super: got root inode
[42949409.730000] yaffs_read_super: d_alloc_root done
[42949409.730000] yaffs_read_super: done
[42949409.730000] yaffs_sync_fs
[42949409.730000] yaffs_clear_inode: ino 1, count 0 null object
[42949409.730000] yaffs_put_super
[42949409.730000] yaffs locking
[42949409.730000] save exit: isCheckpointed 1
[42949409.730000] yaffs unlocking

I have completely erased the partition before mounting it.