xapi-project/sm — pull request #170 by matelakat (2014-06-10 05:47:38+00:00)
Title: CA-134784: Fix race conditions in refcounter

Concurrent refcounter operations on two different refcounters sharing
the same namespace can lead to race conditions:
A.) By the time the refcounter file is written, the namespace directory
has already been removed
B.) Removing a namespace directory fails, because a a new refcounter file
has been created within the same directory

_writeCount now returns False if the file was not found

A is solved by spinning on _writeCount until it succeeds.
B is solved by ignoring such situations.

Signed-off-by: Mate Lakat