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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Benjamin Coddington <bcodding@redhat.com>,
        Chuck Lever <chuck.lever@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 04/37] NFSD: Keep existing listeners on portlist error
Date:   Mon, 25 Oct 2021 21:14:29 +0200
Message-Id: <20211025190929.143886782@linuxfoundation.org>
In-Reply-To: <20211025190926.680827862@linuxfoundation.org>
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From: Benjamin Coddington <bcodding@redhat.com>

[ 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>
---
 fs/nfsd/nfsctl.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index cb69660d0779..ff9899cc9913 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -788,7 +788,10 @@ 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;
 }
 
-- 
2.33.0