Ceph » CephFS

Currently we need the complete flag (or a cached negative dentry) to conclude a name does not exist in a frag before we can create it. This means that (especially for large dirs) once a single dentry is trimmed, we need to reload the whole dir when we have a miss.

We should supplement the complete flag with a bloom filter (which gives false positives but never false negatives), and add trimmed/released items to the filter. If a bloom filter check gives a false, we know the item was never trimmed, and can safely instantiate it.