Re: NFSv4.1 regression with v4.15-rc

[Bruce Fields <bfields@fieldses.org>]

On Wed, Dec 27, 2017 at 03:40:58PM -0500, Chuck Lever wrote:
> Last week I updated my test server from v4.14 to v4.15-rc4, and began to
> observe intermittent failures in the git regression suite on NFSv4.1.

I haven't run that before.  Should I just

	mount -overs=4.1 server:/fs /mnt/
	cd /mnt/
	git clone git://git.kernel.org/pub/scm/git/git.git
	cd git
	make test

?

> I
> was able to reproduce these failures with NFSv4.1 on both TCP and RDMA,
> yet there has not been a reproduction with NFSv3 or NFSv4.0.
> 
> The server hardware is a single-socket 4-core system with 32GB of RAM.
> The export is a tmpfs. Networking is 56Gb InfiniBand (or IPoIB).
> 
> The git regression suite reports individual test failures in the SVN
> and CVS tests. On occasion, the client mount point freezes, requiring
> that the client be rebooted in order to unstick the mount.
> 
> Just before Christmas, I bisected the problem to:

Thanks for the report!  I'll make some time for this next week.  What's
your client?  I guess one start might be to see if the reproducer can be
simplified e.g. by running just one of the tests from the suite.

--b.

> 
> commit 659aefb68eca28ba9aa482a9fc64de107332e256
> Author: Trond Myklebust <trond.myklebust@primarydata.com>
> Date:   Fri Nov 3 08:00:13 2017 -0400
> 
>     nfsd: Ensure we don't recognise lock stateids after freeing them
>     
>     In order to deal with lookup races, nfsd4_free_lock_stateid() needs
>     to be able to signal to other stateful functions that the lock stateid
>     is no longer valid. Right now, nfsd_lock() will check whether or not an
>     existing stateid is still hashed, but only in the "new lock" path.
>     
>     To ensure the stateid invalidation is also recognised by the "existing lock"
>     path, and also by a second call to nfsd4_free_lock_stateid() itself, we can
>     change the type to NFS4_CLOSED_STID under the stp->st_mutex.
>     
>     Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
>     Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> 
> 
> Since we're already at v4.15-rc5 I thought it would be best to break the
> holiday moratorium instead of waiting another week to report this.
> 
> 
> --
> Chuck Lever
> 
>