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[209.132.180.67]) by mx.google.com with ESMTP id d12si27040855pgf.470.2018.11.06.20.16.33; Tue, 06 Nov 2018 20:16:48 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388957AbeKGNnF (ORCPT + 99 others); Wed, 7 Nov 2018 08:43:05 -0500 Received: from mx2.suse.de ([195.135.220.15]:56630 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388530AbeKGNnF (ORCPT ); Wed, 7 Nov 2018 08:43:05 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id E6261B6A2; Wed, 7 Nov 2018 04:14:27 +0000 (UTC) From: NeilBrown To: "J. Bruce Fields" , Chuck Lever , Jeff Layton , Trond Myklebust , Anna Schumaker Date: Wed, 07 Nov 2018 15:12:31 +1100 Subject: [PATCH 09/23] NFSv4: add cl_root_cred for use when machine cred is not available. Cc: Linux NFS Mailing List , linux-kernel@vger.kernel.org Message-ID: <154156395104.24086.17023670588890588198.stgit@noble> In-Reply-To: <154156285766.24086.14262073575778354276.stgit@noble> References: <154156285766.24086.14262073575778354276.stgit@noble> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org NFSv4 state management tries a root credential when no machine credential is available, as can happen with kerberos. It does this by replacing the cl_machine_cred with a root credential. This means that any user of the machine credential needs to take a lock while getting a reference to the machine credential, which is a little cumbersome. So introduce an explicit cl_root_cred, and never free either credential until client shutdown. This means that no locking is needed to reference these credentials. Future patches will make use of this. This is only a temporary addition. both cl_machine_cred and cl_root_cred will disappear later in the series. Signed-off-by: NeilBrown --- fs/nfs/client.c | 2 ++ fs/nfs/nfs4state.c | 20 ++++++++++++-------- include/linux/nfs_fs_sb.h | 1 + 3 files changed, 15 insertions(+), 8 deletions(-) diff --git a/fs/nfs/client.c b/fs/nfs/client.c index 96d5f8135eb9..cce151776709 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -248,6 +248,8 @@ void nfs_free_client(struct nfs_client *clp) if (clp->cl_machine_cred != NULL) put_rpccred(clp->cl_machine_cred); + if (clp->cl_root_cred != NULL) + put_rpccred(clp->cl_root_cred); put_net(clp->cl_net); put_nfs_version(clp->cl_nfs_mod); diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index 62ae0fd345ad..032d3ec929f3 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -166,24 +166,28 @@ int nfs40_discover_server_trunking(struct nfs_client *clp, struct rpc_cred *nfs4_get_machine_cred_locked(struct nfs_client *clp) { - struct rpc_cred *cred = NULL; + struct rpc_cred *cred = clp->cl_root_cred; - if (clp->cl_machine_cred != NULL) - cred = get_rpccred(clp->cl_machine_cred); + if (!cred) + cred = clp->cl_machine_cred; + if (cred) + return get_rpccred(cred); return cred; } static void nfs4_root_machine_cred(struct nfs_client *clp) { - struct rpc_cred *cred, *new; + struct rpc_cred *new; new = rpc_lookup_machine_cred(NULL); spin_lock(&clp->cl_lock); - cred = clp->cl_machine_cred; - clp->cl_machine_cred = new; + if (clp->cl_root_cred == NULL) { + clp->cl_root_cred = new; + new = NULL; + } spin_unlock(&clp->cl_lock); - if (cred != NULL) - put_rpccred(cred); + if (new != NULL) + put_rpccred(new); } static struct rpc_cred * diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h index 0fc0b9135d46..fea51b44fe50 100644 --- a/include/linux/nfs_fs_sb.h +++ b/include/linux/nfs_fs_sb.h @@ -59,6 +59,7 @@ struct nfs_client { u32 cl_minorversion;/* NFSv4 minorversion */ struct rpc_cred *cl_machine_cred; + struct rpc_cred *cl_root_cred; /* Use when machine_cred is ineffective */ #if IS_ENABLED(CONFIG_NFS_V4) struct list_head cl_ds_clients; /* auth flavor data servers */