Dircache: Refine name allocation and error handling.

* 8 bits is enough to allow 260 character base names when five
bytes is the minimum indirect storage size (0..255->5..260).

* Don't truncate anything that's too long as that can lead to
bad behavior, simply don't include the offending entry in the
parent.

* Set the .tinyname flag to 1 by default to indicate that
the entry's name doesn't need freeing. Clear it only when
allocating indirect storage.

* Rename some things to help catch all instances

Change-Id: Iff747b624acbb8e03ed26c24afdf0fc715fd9d99
3 files changed