fmt cleanups; add new serialized dents to the srv type

Signed-off-by: Ronald G. Minnich <rminnich@google.com>
Redo the readdir logic

Serialize it all. It makes zero sense to do it the way it was
being done given that arbitrary offsets are allowed on read.

Signed-off-by: Ronald G. Minnich <rminnich@google.com>