feat(tvix/castore/fs): implement opendir/releasedir r/7915

Similar to how we already handle opening files, implement opendir/
releasedir, and keep a map of dir_handles. They point to the rx side of
a channel.

This greatly improves performance listing the root of the filesystem
when used inside tvix-store, as we don't need to re-request the listing
(and skip to the desired position) all the time.

Change-Id: I0d3ec4cb70a8792c5a1343439cf47d78d9cbb1d6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11425
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI

0 files changed, 0 insertions, 0 deletions