* since the last caller of is_read_only() is gone, the function
itself is removed.
	* destroy_buffers() is not used anymore; gone.
	* fsync_dev() is gone; the only user is (broken) lvm.c and first
step in fixing lvm.c will consist of propagating struct block_device *
anyway; at that point we'll just use fsync_bdev() in there.
	* prototype of bio_ioctl() removed - function doesn't exist
anymore.