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 <jlayton@xxxxxxxxxx>
---
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
--
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