[QUANTAL][SRU][PATCH 0/2] Fix for LP#1226726

[Chris J Arges]

BugLink: http://bugs.launchpad.net/bugs/1226726

SRU Justification:

Impact: When creating thousands of network namespaces the delay in executing
commands increases exponentially in kernels before 84d17192.

Fix: In 84d17192 in the upstream kernel, locking code in fs/namespace.c
is greatly improved resulting in much better performance when the number
namespaces increase.

Testcase: Below, test_ns.sh can be run and a graph can be compared between
the existing version and the patched version.

Additional Information: Because this is a change in the vfs layer, I ran the
xfstests and compared before and after results of this patch. The patch did
not create any additional failures in the generic xfstests.

The quantal and raring solutions differ but are both based on the 84d17192
patch. The quantal solution does a backport of this patch instead of clean
cherry-picks because of the amount of deps required to just use cherry-picks.
The raring solution was able to be done with two clean cherry-picks and that's
why that solution was chosen.