This patch is a reimplementation of name cache based off tcache, and it now bears a striking resemblance to the attribute cache.  There was a significant API change, but that did not have an effect other than fixing the calls already in place.  There are no changes to the wire protocol or the storage format.  It also includes perf-counter support for monitoring.

The state machines have several changes to use the new API, but the functionality stayed the same in most places.  Sys-readdir.sm and sys-lookup.sm had some minor changes/additions to make ncache update properly. Lookup-ncache.sm now only checks the cache for one segment of the path at a time instead of the entire path at once.   The new ncache stores individual path segments independently.

There were updates to pvfs2-client.c and pvfs2-client-core.c to accept the new ncache options and deal with them appropriately. There were also additions in upcall.h and pvfs2-proc.c.  Pvfs2-proc has a generalization of one of the functions to be used for both attribute cache and name cache.

Tuning for ncache can be done with the proc files in /proc/sys/pvfs2/ncache.  They mimic the acache options: hard-limit, soft-limit, reclaim-percentage, and timeout-msecs.  The performace counters also imitate acache and are located in /proc/sys/pvfs2/perf-counters/ncache.
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