sunrpc: fixed rollback in rpc_gssd_dummy_populate()

BugLink: https://bugs.launchpad.net/bugs/1885932

commit b7ade381 upstream.

__rpc_depopulate(gssd_dentry) was lost on error path

cc: stable@vger.kernel.org
Fixes: commit 4b9a445e ("sunrpc: create a new dummy pipe for gssd to hold open")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

net/sunrpc/rpc_pipe.c

@@ -1347,6 +1347,7 @@ rpc_gssd_dummy_populate(struct dentry *root, struct rpc_pipe *pipe_data)
 	q.len = strlen(gssd_dummy_clnt_dir[0].name);
 	clnt_dentry = d_hash_and_lookup(gssd_dentry, &q);
 	if (!clnt_dentry) {
+		__rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
 		pipe_dentry = ERR_PTR(-ENOENT);
 		goto out;
 	}