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From:   trondmy@kernel.org
To:     linux-nfs@vger.kernel.org
Subject: [PATCH 1/4] SUNRPC: Fix races when closing the socket
Date:   Fri, 29 Oct 2021 16:04:18 -0400
Message-Id: <20211029200421.65090-1-trondmy@kernel.org>
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From: Trond Myklebust <trond.myklebust@hammerspace.com>

Ensure that we bump the xprt->connect_cookie when we set the
XPRT_CLOSE_WAIT flag so that another call to
xprt_conditional_disconnect() won't race with the reconnection.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 net/sunrpc/xprt.c     | 2 ++
 net/sunrpc/xprtsock.c | 1 +
 2 files changed, 3 insertions(+)

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 48560188e84d..691fe5a682b6 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -735,6 +735,8 @@ static void xprt_autoclose(struct work_struct *work)
 	unsigned int pflags = memalloc_nofs_save();
 
 	trace_xprt_disconnect_auto(xprt);
+	xprt->connect_cookie++;
+	smp_mb__before_atomic();
 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
 	xprt->ops->close(xprt);
 	xprt_release_write(xprt, NULL);
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 04f1b78bcbca..b18d13479104 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1134,6 +1134,7 @@ static void xs_run_error_worker(struct sock_xprt *transport, unsigned int nr)
 
 static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
 {
+	xprt->connect_cookie++;
 	smp_mb__before_atomic();
 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
 	clear_bit(XPRT_CLOSING, &xprt->state);
-- 
2.31.1