From patchwork Fri Apr 18 18:44:28 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Trond Myklebust X-Patchwork-Id: 4017861 Return-Path: X-Original-To: patchwork-linux-nfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 73ABC9F2BA for ; Fri, 18 Apr 2014 18:46:42 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9A960203AF for ; Fri, 18 Apr 2014 18:46:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C83F7203AC for ; Fri, 18 Apr 2014 18:46:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754544AbaDRSqj (ORCPT ); Fri, 18 Apr 2014 14:46:39 -0400 Received: from mail-ig0-f176.google.com ([209.85.213.176]:57160 "EHLO mail-ig0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754327AbaDRSp7 (ORCPT ); Fri, 18 Apr 2014 14:45:59 -0400 Received: by mail-ig0-f176.google.com with SMTP id uy17so957790igb.3 for ; Fri, 18 Apr 2014 11:45:59 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=bT+NEFSWLGororWCMrKplN26j8S7zWNGsLynFZkgrAk=; b=Ukcy+xZZevRiwCUUotiq9fG+2XnnQwi7vjFnK9vSEvFSRpxQFr9QUC+qa8GpJqKAck Cf1IefMjofaTUYdx+iAYD3NXJjBU0pePgjoEcY/xK88gsQkvGB3pyhSicwAnFQ0zOghC ofyp6JIw2EknkTZ2ZQyteIWT2wOT3brXC6hrSwk/LP0GQ+LHwHkcF6DLmLq2mYB5tY2C iSMyecpn/9Rf4BKixxISiyRHuC4s6nOSuo+mfY8JB19dooAaiqT3TKiEJQmm3A2SJXlr 53o/13hYqkq1hRe9qvDUBpy+HBTjI9JSK2thF+SGBPi1/Y0NqKacYK9b4pYY0TErNAYj /SMw== X-Gm-Message-State: ALoCoQlzhwrtUBB9Q7ImTADJlA8vcx7SAEUksxv1f4DPEAK2bO135AvuuYQFH4PZg5Axbl7UFJY3 X-Received: by 10.42.206.9 with SMTP id fs9mr17007472icb.33.1397846759246; Fri, 18 Apr 2014 11:45:59 -0700 (PDT) Received: from leira.trondhjem.org.localdomain (50-124-5-70.drr02.mskg.mi.frontiernet.net. [50.124.5.70]) by mx.google.com with ESMTPSA id j9sm6018922igu.10.2014.04.18.11.45.58 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 18 Apr 2014 11:45:58 -0700 (PDT) From: Trond Myklebust To: Bruce Fields Cc: linux-nfs@vger.kernel.org Subject: [PATCH 34/70] NFSd: Fix atomicity of delegation counter Date: Fri, 18 Apr 2014 14:44:28 -0400 Message-Id: <1397846704-14567-35-git-send-email-trond.myklebust@primarydata.com> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1397846704-14567-34-git-send-email-trond.myklebust@primarydata.com> References: <1397846704-14567-1-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-2-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-3-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-4-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-5-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-6-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-7-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-8-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-9-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-10-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-11-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-12-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-13-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-14-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-15-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-16-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-17-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-18-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-19-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-20-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-21-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-22-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-23-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-24-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-25-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-26-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-27-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-28-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-29-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-30-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-31-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-32-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-33-git-send-email-trond.myklebust@primarydata.com> <1397846704-14567-34-git-send-email-trond.myklebust@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Signed-off-by: Trond Myklebust --- fs/nfsd/nfs4state.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index f463aaf9cd13..87464802126a 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -304,7 +304,7 @@ static struct file *find_any_file(struct nfs4_file *f) return ret; } -static int num_delegations; +static atomic_long_t num_delegations; unsigned long max_delegations; /* @@ -439,18 +439,19 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct sv struct nfs4_delegation *dp; dprintk("NFSD alloc_init_deleg\n"); - if (num_delegations > max_delegations) - return NULL; + atomic_long_inc(&num_delegations); + smp_mb__after_atomic_inc(); + if (atomic_long_read(&num_delegations) > max_delegations) + goto out_dec; dp = delegstateid(nfs4_alloc_stid(clp, deleg_slab)); if (dp == NULL) - return dp; + goto out_dec; /* * delegation seqid's are never incremented. The 4.1 special * meaning of seqid 0 isn't meaningful, really, but let's avoid * 0 anyway just for consistency and use 1: */ dp->dl_stid.sc_stateid.si_generation = 1; - num_delegations++; INIT_LIST_HEAD(&dp->dl_perfile); INIT_LIST_HEAD(&dp->dl_perclnt); INIT_LIST_HEAD(&dp->dl_recall_lru); @@ -459,6 +460,10 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct sv dp->dl_time = 0; nfsd4_init_callback(&dp->dl_recall); return dp; +out_dec: + atomic_long_dec(&num_delegations); + smp_mb__after_atomic_dec(); + return NULL; } static void remove_stid_locked(struct nfs4_client *clp, struct nfs4_stid *s) @@ -490,8 +495,10 @@ static bool nfs4_put_stid(struct kmem_cache *slab, struct nfs4_stid *s) void nfs4_put_delegation(struct nfs4_delegation *dp) { - if (nfs4_put_stid(deleg_slab, &dp->dl_stid)) - num_delegations--; + if (nfs4_put_stid(deleg_slab, &dp->dl_stid)) { + atomic_long_dec(&num_delegations); + smp_mb__after_atomic_dec(); + } } /* Call under fp->fi_lock */