ZFS: Deadlock during vnode recycling

[Justin T. Gibbs]

On Oct 7, 2012, at 9:32 AM, Andriy Gapon <avg at FreeBSD.org> wrote:

> In fact here is a real patch that I would like to propose:
> http://people.freebsd.org/~avg/zfs-getnewvnode_reserve.diff

OS-X has these same types of problems and I talked with Don Brady
of the OS-X ZFS port about them during ZFS day.  It sounds like he
explicitly pre-allocates vnodes in these code paths instead of
relying on a reserve pool.  I plan to review his work since I expect
he's found and fixed problems we don't even know we have yet.

My only complaint with this patch is that it doesn't include stats
counters for these rare conditions so that I can validate that the
code is exercised during a test suite.  Can you merge in the kstat
portion of the change I proposed?

--
Justin