NFSD: Keep existing listeners on portlist error

BugLink: https://bugs.launchpad.net/bugs/1951295
[ Upstream commit c20106944eb679fa3ab7e686fe5f6ba30fbc51e5 ]

If nfsd has existing listening sockets without any processes, then an error
returned from svc_create_xprt() for an additional transport will remove
those existing listeners.  We're seeing this in practice when userspace
attempts to create rpcrdma transports without having the rpcrdma modules
present before creating nfsd kernel processes.  Fix this by checking for
existing sockets before calling nfsd_destroy().

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 8e03d6c25097a1fb1aab420b533c5e46009ef696..730386c130e0f1106003e46537a2236817de6be1 100644 (file)
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -792,7 +792,10 @@ out_close:
                svc_xprt_put(xprt);
        }
 out_err:
-       nfsd_destroy(net);
+       if (!list_empty(&nn->nfsd_serv->sv_permsocks))
+               nn->nfsd_serv->sv_nrthreads--;
+        else
+               nfsd_destroy(net);
        return err;
 }