Return-Path: Received: from mx2.suse.de ([195.135.220.15]:38485 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751000AbeBSFEF (ORCPT ); Mon, 19 Feb 2018 00:04:05 -0500 From: NeilBrown To: Trond Myklebust , Anna Schumaker Date: Mon, 19 Feb 2018 16:02:29 +1100 Subject: [PATCH 09/23] NFSv4: add cl_root_cred for use when machine cred is not available. Cc: linux-nfs@vger.kernel.org Message-ID: <151901654905.17421.13619498648448266985.stgit@noble> In-Reply-To: <151901634940.17421.7637564368419392071.stgit@noble> References: <151901634940.17421.7637564368419392071.stgit@noble> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: 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 b9129e2befea..e101b67ca5ba 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 91a4d4eeb235..bfbc9a87d09d 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -158,24 +158,28 @@ 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 4e735be53e70..ca3f14b0f738 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 */