Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-qe0-f50.google.com ([209.85.128.50]:45369 "EHLO mail-qe0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754656Ab3KLNAd (ORCPT ); Tue, 12 Nov 2013 08:00:33 -0500 Received: by mail-qe0-f50.google.com with SMTP id 1so5575114qee.9 for ; Tue, 12 Nov 2013 05:00:33 -0800 (PST) From: Jeff Layton To: trond.myklebust@netapp.com Cc: linux-nfs@vger.kernel.org, steved@redhat.com Subject: [PATCH 1/2] sunrpc: create a new dummy pipe for gssd to hold open Date: Tue, 12 Nov 2013 08:00:24 -0500 Message-Id: <1384261225-28559-2-git-send-email-jlayton@redhat.com> In-Reply-To: <1384261225-28559-1-git-send-email-jlayton@redhat.com> References: <1384261225-28559-1-git-send-email-jlayton@redhat.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: rpc.gssd will naturally hold open any pipe named */clnt*/gssd that shows up under rpc_pipefs. That behavior gives us a reliable mechanism to tell whether it's actually running or not. Create a new toplevel "dummy" directory in rpc_pipefs when it's mounted. Under that directory create another directory called "clntXX", and then within that a pipe called "gssd". We'll never send an upcall along that pipe, and any downcall written to it will just return -EINVAL. Signed-off-by: Jeff Layton --- net/sunrpc/netns.h | 1 + net/sunrpc/rpc_pipe.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 85 insertions(+) diff --git a/net/sunrpc/netns.h b/net/sunrpc/netns.h index 779742c..6b82968 100644 --- a/net/sunrpc/netns.h +++ b/net/sunrpc/netns.h @@ -15,6 +15,7 @@ struct sunrpc_net { struct super_block *pipefs_sb; struct mutex pipefs_sb_lock; + struct dentry *gssd_dummy; struct list_head all_clients; spinlock_t rpc_client_lock; diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c index f94567b..1c54de6 100644 --- a/net/sunrpc/rpc_pipe.c +++ b/net/sunrpc/rpc_pipe.c @@ -1168,6 +1168,7 @@ enum { RPCAUTH_nfsd4_cb, RPCAUTH_cache, RPCAUTH_nfsd, + RPCAUTH_dummy, RPCAUTH_RootEOF }; @@ -1204,6 +1205,10 @@ static const struct rpc_filelist files[] = { .name = "nfsd", .mode = S_IFDIR | S_IRUGO | S_IXUGO, }, + [RPCAUTH_dummy] = { + .name = "dummy", + .mode = S_IFDIR | S_IRUGO | S_IXUGO, + }, }; /* @@ -1253,6 +1258,80 @@ void rpc_put_sb_net(const struct net *net) } EXPORT_SYMBOL_GPL(rpc_put_sb_net); +static const struct rpc_filelist dummy_clnt_dir[] = { + [0] = { + .name = "clntXX", + .mode = S_IFDIR | S_IRUGO | S_IXUGO, + }, +}; + +static ssize_t +dummy_downcall(struct file *filp, const char __user *src, size_t len) +{ + return -EINVAL; +} + +static const struct rpc_pipe_ops dummy_pipe_ops = { + .upcall = rpc_pipe_generic_upcall, + .downcall = dummy_downcall, +}; + +/** + * rpc_gssd_dummy_populate - create a dummy gssd pipe + * @root: root of the rpc_pipefs filesystem + * + * Create a dummy set of directories and a pipe that gssd can hold open to + * indicate that it is up and running. + */ +static struct dentry * +rpc_gssd_dummy_populate(struct dentry *root) +{ + int ret = 0; + struct dentry *gssd_dentry; + struct dentry *clnt_dentry = NULL; + struct dentry *pipe_dentry = NULL; + struct rpc_pipe *pipe_data = NULL; + struct qstr q = QSTR_INIT(files[RPCAUTH_dummy].name, + strlen(files[RPCAUTH_dummy].name)); + + /* We should never get this far if "gssd" doesn't exist */ + gssd_dentry = d_hash_and_lookup(root, &q); + if (!gssd_dentry) + return ERR_PTR(-ENOENT); + + ret = rpc_populate(gssd_dentry, dummy_clnt_dir, 0, 1, NULL); + if (ret) { + pipe_dentry = ERR_PTR(ret); + goto out; + } + + pipe_data = rpc_mkpipe_data(&dummy_pipe_ops, 0); + if (IS_ERR(pipe_data)) { + pipe_dentry = ERR_CAST(pipe_data); + pipe_data = NULL; + goto out; + } + + q.name = dummy_clnt_dir[0].name; + q.len = strlen(dummy_clnt_dir[0].name); + clnt_dentry = d_hash_and_lookup(gssd_dentry, &q); + if (!clnt_dentry) { + pipe_dentry = ERR_PTR(-ENOENT); + goto out; + } + + pipe_dentry = rpc_mkpipe_dentry(clnt_dentry, "gssd", NULL, pipe_data); + if (IS_ERR(pipe_dentry)) + goto out; + + pipe_data = NULL; +out: + rpc_destroy_pipe_data(pipe_data); + dput(clnt_dentry); + dput(gssd_dentry); + return pipe_dentry; +} + static int rpc_fill_super(struct super_block *sb, void *data, int silent) { @@ -1275,6 +1354,11 @@ rpc_fill_super(struct super_block *sb, void *data, int silent) return -ENOMEM; if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL)) return -ENOMEM; + + sn->gssd_dummy = rpc_gssd_dummy_populate(root); + if (IS_ERR(sn->gssd_dummy)) + return PTR_ERR(sn->gssd_dummy); + dprintk("RPC: sending pipefs MOUNT notification for net %p%s\n", net, NET_NAME(net)); mutex_lock(&sn->pipefs_sb_lock); -- 1.8.3.1