The biggest overall change is the move to using dataspace attributes for storing basic metadata for PVFS2 objects.
Directories are made up of a single dataspace. Dataspace attributes are used to store basic metadata. Keyvals in the dataspace are used to store the directory entries in (short name, handle) format as before.
Metafiles are made up of a single dataspace. Basic metadata is stored in the dataspace attributes as with directories. The keyval space is used to store additional attributes, including the list of datafile handles (TODO: WHAT ELSE?).
Datafiles are made up of a single Trove dataspace, with basic metadata stored in the dataspace attributes and data stored in the bstream (TODO: WHAT KEY?).
Symlinks are made up of a single Trove dataspace with basic metadata (if any?) stored in the dataspace attributes and target stored as a keyval (TODO: WHAT KEY?).