crypto: fix moving read head
crypto: fix moving read head

Fix various possible stalls of read head (i.e. try moving it after every
write head update).

NOTE: This is actually backported from `bud`.

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node