From patchwork Wed Jun 15 03:28:05 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleg Drokin X-Patchwork-Id: 9177465 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id AB38F604DB for ; Wed, 15 Jun 2016 03:33:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9CF5D280E0 for ; Wed, 15 Jun 2016 03:33:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 90CFE28356; Wed, 15 Jun 2016 03:33:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8CB6D280E0 for ; Wed, 15 Jun 2016 03:33:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932754AbcFODcw (ORCPT ); Tue, 14 Jun 2016 23:32:52 -0400 Received: from linuxhacker.ru ([217.76.32.60]:51486 "EHLO fiona.linuxhacker.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161091AbcFOD22 (ORCPT ); Tue, 14 Jun 2016 23:28:28 -0400 Received: from intelbox2.localnet (c-73-190-129-164.hsd1.tn.comcast.net [73.190.129.164]) (authenticated bits=0) by fiona.linuxhacker.ru (8.15.2/8.14.7) with ESMTPSA id u5F3SDcD588010 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 15 Jun 2016 06:28:18 +0300 From: Oleg Drokin To: Jeff Layton , "J . Bruce Fields" Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, Oleg Drokin Subject: [PATCH 2/3] nfsd: Extend the mutex holding region around in nfsd4_process_open2() Date: Tue, 14 Jun 2016 23:28:05 -0400 Message-Id: <1465961286-925636-3-git-send-email-green@linuxhacker.ru> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1465961286-925636-1-git-send-email-green@linuxhacker.ru> References: <1465945026.12291.5.camel@poochiereds.net> <1465961286-925636-1-git-send-email-green@linuxhacker.ru> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP To avoid racing entry into nfs4_get_vfs_file(). Make init_open_stateid() return with locked stateid to be unlocked by the caller. Signed-off-by: Oleg Drokin --- fs/nfsd/nfs4state.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index c927d36..94854a0 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -3487,6 +3487,10 @@ init_open_stateid(struct nfs4_ol_stateid *stp, struct nfs4_file *fp, struct nfs4_openowner *oo = open->op_openowner; struct nfs4_ol_stateid *retstp = NULL; + /* We are moving these outside of the spinlocks to avoid the warnings */ + mutex_init(&stp->st_mutex); + mutex_lock(&stp->st_mutex); + spin_lock(&oo->oo_owner.so_client->cl_lock); spin_lock(&fp->fi_lock); @@ -3502,13 +3506,17 @@ init_open_stateid(struct nfs4_ol_stateid *stp, struct nfs4_file *fp, stp->st_access_bmap = 0; stp->st_deny_bmap = 0; stp->st_openstp = NULL; - mutex_init(&stp->st_mutex); list_add(&stp->st_perstateowner, &oo->oo_owner.so_stateids); list_add(&stp->st_perfile, &fp->fi_stateids); out_unlock: spin_unlock(&fp->fi_lock); spin_unlock(&oo->oo_owner.so_client->cl_lock); + if (retstp) { + mutex_lock(&retstp->st_mutex); + /* Not that we need to, just for neatness */ + mutex_unlock(&stp->st_mutex); + } return retstp; } @@ -4344,11 +4352,14 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf } else { stp = open->op_stp; open->op_stp = NULL; + /* + * init_open_stateid() either returns a locked stateid + * it found, or initializes and locks the new one we passed in + */ swapstp = init_open_stateid(stp, fp, open); if (swapstp) { nfs4_put_stid(&stp->st_stid); stp = swapstp; - mutex_lock(&stp->st_mutex); status = nfs4_upgrade_open(rqstp, fp, current_fh, stp, open); if (status) { @@ -4357,7 +4368,6 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf } goto upgrade_out; } - mutex_lock(&stp->st_mutex); status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open); if (status) { mutex_unlock(&stp->st_mutex);