From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754277AbcGYVCh (ORCPT ); Mon, 25 Jul 2016 17:02:37 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46043 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753968AbcGYU5I (ORCPT ); Mon, 25 Jul 2016 16:57:08 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oleg Drokin , "J. Bruce Fields" Subject: [PATCH 4.4 032/146] nfsd: Extend the mutex holding region around in nfsd4_process_open2() Date: Mon, 25 Jul 2016 13:54:47 -0700 Message-Id: <20160725203522.699392222@linuxfoundation.org> X-Mailer: git-send-email 2.9.0 In-Reply-To: <20160725203521.340401316@linuxfoundation.org> References: <20160725203521.340401316@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleg Drokin commit 5cc1fb2a093e254b656c64ff24b0b76bed1d34d9 upstream. 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 Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/nfs4state.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -3452,6 +3452,10 @@ init_open_stateid(struct nfs4_ol_stateid 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); @@ -3467,13 +3471,17 @@ init_open_stateid(struct nfs4_ol_stateid 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; } @@ -4309,11 +4317,14 @@ nfsd4_process_open2(struct svc_rqst *rqs } 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) { @@ -4322,7 +4333,6 @@ nfsd4_process_open2(struct svc_rqst *rqs } 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);