From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 828D9C3A589 for ; Thu, 15 Aug 2019 19:54:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 55C712084D for ; Thu, 15 Aug 2019 19:54:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730148AbfHOTyE (ORCPT ); Thu, 15 Aug 2019 15:54:04 -0400 Received: from fieldses.org ([173.255.197.46]:34694 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729818AbfHOTyE (ORCPT ); Thu, 15 Aug 2019 15:54:04 -0400 Received: by fieldses.org (Postfix, from userid 2815) id 3B0CA63F; Thu, 15 Aug 2019 15:54:04 -0400 (EDT) Date: Thu, 15 Aug 2019 15:54:04 -0400 To: linux-nfs@vger.kernel.org Subject: [PATCH] nfsd: use i_wrlock instead of rcu for nfsdfs i_private Message-ID: <20190815195404.GA19554@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) From: bfields@fieldses.org (J. Bruce Fields) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: "J. Bruce Fields" synchronize_rcu() gets called multiple times each time a client is destroyed. If the laundromat thread has a lot of clients to destroy, the delay can be noticeable. This was causing pynfs test RENEW3 to fail. We could embed an rcu_head in each inode and do the kref_put in an rcu callback. But simplest is just to take a lock here. (I also wonder if the laundromat thread would be better replaced by a bunch of scheduled work or timers or something.) Signed-off-by: J. Bruce Fields --- fs/nfsd/nfsctl.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index 928a0b2c05dc..b14f825c62fe 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -1215,11 +1215,9 @@ static void clear_ncl(struct inode *inode) struct nfsdfs_client *ncl = inode->i_private; inode->i_private = NULL; - synchronize_rcu(); kref_put(&ncl->cl_ref, ncl->cl_release); } - static struct nfsdfs_client *__get_nfsdfs_client(struct inode *inode) { struct nfsdfs_client *nc = inode->i_private; @@ -1233,9 +1231,9 @@ struct nfsdfs_client *get_nfsdfs_client(struct inode *inode) { struct nfsdfs_client *nc; - rcu_read_lock(); + inode_lock_shared(inode); nc = __get_nfsdfs_client(inode); - rcu_read_unlock(); + inode_unlock_shared(inode); return nc; } /* from __rpc_unlink */ -- 2.21.0