Shrink critical sections in lookup_hash and lookup_ino.

Signed-off-by: Matt Benjamin <matt@linuxbox.com>
Unserialize ll_walk.

A lock transition can be elided, left for a future change.

Signed-off-by: Matt Benjamin <matt@linuxbox.com>
Unserialize ll_forget.

This includes adding the cf flags argument to path_walk.

Signed-off-by: Matt Benjamin <matt@linuxbox.com>