SUNRPC: 'Directory with parent 'rpc_clnt' already present!'

Each rpc_client has a cl_clid which is allocated from a global ida, and
a debugfs directory which is named after cl_clid.

We're releasing the cl_clid before we free the debugfs directory named
after it.  As soon as the cl_clid is released, that value is available
for another newly created client.

That leaves a window where another client may attempt to create a new
debugfs directory with the same name as the not-yet-deleted debugfs
directory from the dying client.  Symptoms are log messages like

	Directory 4 with parent 'rpc_clnt' already present!

Fixes: 7c4310ff5642 "SUNRPC: defer slow parts of rpc_free_client() to a workqueue."
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index c74bc402f8c79bbaa6f9356ae06c37309a722e94..61b21dafd7c0da1538ec8705d78372d67090dbb2 100644 (file)
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -889,6 +889,7 @@ static void rpc_free_client_work(struct work_struct *work)
         * here.
         */
        rpc_clnt_debugfs_unregister(clnt);
+       rpc_free_clid(clnt);
        rpc_clnt_remove_pipedir(clnt);
        xprt_put(rcu_dereference_raw(clnt->cl_xprt));
 
@@ -910,7 +911,6 @@ rpc_free_client(struct rpc_clnt *clnt)
        clnt->cl_metrics = NULL;
        xprt_iter_destroy(&clnt->cl_xpi);
        put_cred(clnt->cl_cred);
-       rpc_free_clid(clnt);
 
        INIT_WORK(&clnt->cl_work, rpc_free_client_work);
        schedule_work(&clnt->cl_work);