[git pull] fix for nasty races in br_write_lock()

[Al Viro <viro@ZenIV.linux.org.uk>]

	There's a nasty race between CPU hotplug and br_write_lock();
the latter pretty much assumes that the set of online CPUs can't change
between br_write_lock() and br_write_unlock().  Caught by Cong Meng,
solution hashed out during the last few days between me and Srivatsa S. Bhat
on l-k/fsdevel thread, appears to fix the problem in a reasonably sane
way.  It'll need to go into -stable as well; all branches since 2.6.36.
Please, pull from the usual place;
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git for-linus

Shortlog:
Srivatsa S. Bhat (1):
      VFS: Fix race between CPU hotplug and lglocks

Diffstat:
 include/linux/lglock.h |   36 ++++++++++++++++++++++++++++++++----
 1 files changed, 32 insertions(+), 4 deletions(-)