From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-194.mimecast.com ([216.205.24.194]:47158 "EHLO us-smtp-delivery-194.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755669AbcHSPpZ (ORCPT ); Fri, 19 Aug 2016 11:45:25 -0400 From: Trond Myklebust To: Kornievskaia Olga CC: Kinglong Mee , List Linux NFS Mailing Subject: Re: [PATCH v2 1/2] NFSv4: Ensure that we drain the session before shutting it down Date: Fri, 19 Aug 2016 15:45:13 +0000 Message-ID: <9E62B7D6-D683-4F92-BA63-8183D21498FF@primarydata.com> References: <1427142109-91216-1-git-send-email-trond.myklebust@primarydata.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=WINDOWS-1252 Sender: linux-nfs-owner@vger.kernel.org List-ID: > On Aug 19, 2016, at 09:41, Olga Kornievskaia wrote: >=20 > Hi Trond, Kinglong, >=20 > What has happened to this patch? It was dropped, since it should be unnecessary. The delegreturn calls from = nfs4_evict_inode() should now be synchronous, and other calls should normal= ly grab a reference to the inode+super block. >=20 > I believe the lack of this patch is causing the following problem on > the nfsv4.1 mount: > 1. client has delegations > 2. unmount is initiated which as Kinglong points out: > -- initiates asynchronous DELEGRETURNs. > -- then in nfs_free_server() it ends up killing ongoing rpc tasks with > DELEGRETURN. > -- nfs41_proc_sequence() takes a reference on the client structure. > However since the RPCs are killed there is no call to nfs_put_client() > which is done in the nfs4_sequence_release() task->tk_ops->rpc_release() is guaranteed to be run. > -- then in nfs_put_client() the reference count doesn't go down to 0 > and DESTROY_SESSION isn't called. The user's umount succeeds but we > still have the client structure with a session.