From: "Andy Chittenden" <andyc.bluearc-Re5JQEeQqe8AvxtiuMwx3w@public•gmane.org>
To: "'Andy Chittenden'"
<andyc.bluearc-Re5JQEeQqe8AvxtiuMwx3w@public•gmane.org>,
"'Andrew Morton'"
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public•gmane.org>
Cc: "'David Miller'" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public•gmane.org>,
<kuznet-v/Mj1YrvjDBInbfyfbPRSQ@public•gmane.org>,
<pekkas-UjJjq++bwZ7HOG6cAo2yLw@public•gmane.org>,
<jmorris-gx6/JNMH7DfYtjvyW6yDsg@public•gmane.org>,
<yoshfuji-VfPWfsRibaP+Ru+s062T9g@public•gmane.org>,
<kaber-dcUjhNyLwpNeoWH0uzbU5w@public•gmane.org>,
<eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public•gmane.org>,
<William.Allen.Simpson-Re5JQEeQqe8AvxtiuMwx3w@public•gmane.org>,
<gilad-f4XOiQkOAtcdH0auuBZGHA@public•gmane.org>,
<ilpo.jarvinen-pxSi+dnQzZMxHbG02/KK1g@public•gmane.org>,
<netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>,
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>,
<linux-nfs-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>,
"'Trond Myklebust'"
<Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public•gmane.org>,
"'J. Bruce Fields'"
<bfields-uC3wQj2KruNg9hUCZPvPmw@public•gmane.org>,
"'Neil Brown'" <neilb-l3A5Bk7waGM@public•gmane.org>,
"'Chuck Lever'"
<chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public•gmane.org>,
"'Benny Halevy'"
<bhalevy-C4P08NqkoRlBDgjK7y7TUQ@public•gmane.org>,
"'Alexandros Batsakis'"
<batsakis-HgOvQuBEEgTQT0dZR+AlfA@public•gmane.org>,
"'Joe Perches'" <joe-6d6DIl74uiNBDgjK7y7TUQ@public•gmane.org>
Subject: RE: [PATCH] [Bug 16494] NFS client over TCP hangs due to packet loss
Date: Thu, 5 Aug 2010 15:55:17 +0100 [thread overview]
Message-ID: <4c5ad0d6.42ecd80a.47d7.0dfc@mx.google.com> (raw)
In-Reply-To: <4C57EE9A.7040308-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> On 2010-08-03 10:11, Andrew Morton wrote:
> > (cc linux-nfs)
> >
> > On Tue, 03 Aug 2010 01:21:44 -0700 (PDT) David
> Miller<davem-fT/PcQaiUtIeIZ0/mPfg9Q@public•gmane.org> wrote:
> >
> >> From: "Andy Chittenden"<andyc.bluearc-Re5JQEeQqe8AvxtiuMwx3w@public•gmane.org>
> >> Date: Tue, 3 Aug 2010 09:14:31 +0100
> >>
> >>> I don't know whether this patch is the correct fix or not but it
> enables the
> >>> NFS client to recover.
> >>>
> >>> Kernel version: 2.6.34.1 and 2.6.32.
> >>>
> >>> Fixes<https://bugzilla.kernel.org/show_bug.cgi?id=16494>. It clears
> down
> >>> any previous shutdown attempts so that reconnects on a socket
> that's been
> >>> shutdown leave the socket in a usable state (otherwise
> tcp_sendmsg() returns
> >>> -EPIPE).
> >>
> >> If the SunRPC code wants to close a TCP socket then use it again,
> >> it should disconnect by doing a connect() with sa_family ==
> AF_UNSPEC
>
> There is code to do that in the SunRPC code in xs_abort_connection()
> but
> that's conditionally called from xs_tcp_reuse_connection():
>
> static void xs_tcp_reuse_connection(struct rpc_xprt *xprt, struct
> sock_xprt *transport)
> {
> unsigned int state = transport->inet->sk_state;
>
> if (state == TCP_CLOSE && transport->sock->state ==
> SS_UNCONNECTED)
> return;
> if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT))
> return;
> xs_abort_connection(xprt, transport);
> }
>
> That's changed since 2.6.26 where it unconditionally did the connect()
> with sa_family == AF_UNSPEC. FWIW we cannot reproduce this problem with
> 2.6.26.
The problem is fixed with this patch which also prints out that sk_shutdown
can be non-zero on entry to xs_tcp_reuse_connection:
# diff -up /home/company/software/src/linux-2.6.34.2/net/sunrpc/xprtsock.c
net/sunrpc/xprtsock.c
--- /home/company/software/src/linux-2.6.34.2/net/sunrpc/xprtsock.c
2010-08-02 18:30:51.000000000 +0100
+++ net/sunrpc/xprtsock.c 2010-08-05 12:21:11.000000000 +0100
@@ -1322,10 +1322,11 @@ static void xs_tcp_state_change(struct s
if (!(xprt = xprt_from_sock(sk)))
goto out;
dprintk("RPC: xs_tcp_state_change client %p...\n", xprt);
- dprintk("RPC: state %x conn %d dead %d zapped %d\n",
+ dprintk("RPC: state %x conn %d dead %d zapped %d sk_shutdown
%d\n",
sk->sk_state, xprt_connected(xprt),
sock_flag(sk, SOCK_DEAD),
- sock_flag(sk, SOCK_ZAPPED));
+ sock_flag(sk, SOCK_ZAPPED),
+ sk->sk_shutdown);
switch (sk->sk_state) {
case TCP_ESTABLISHED:
@@ -1796,10 +1797,18 @@ static void xs_tcp_reuse_connection(stru
{
unsigned int state = transport->inet->sk_state;
- if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED)
- return;
- if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT))
- return;
+ if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED)
{
+ if (transport->inet->sk_shutdown == 0)
+ return;
+ printk("%s: TCP_CLOSEd and sk_shutdown set to %d\n",
+ __func__, transport->inet->sk_shutdown);
+ }
+ if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT)) {
+ if (transport->inet->sk_shutdown == 0)
+ return;
+ printk("%s: sk_shutdown set to %d\n",
+ __func__, transport->inet->sk_shutdown);
+ }
xs_abort_connection(xprt, transport);
}
Signed-off-by: Andy Chittenden <andyc.bluearc-Re5JQEeQqe8AvxtiuMwx3w@public•gmane.org>
dmesg displays:
[ 2840.896043] xs_tcp_reuse_connection: TCP_CLOSEd and sk_shutdown set to 2
so previously the code was attempting to reuse the connection but wasn't
aborting it and thus didn't clear down sk_shutdown.
--
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next prev parent reply other threads:[~2010-08-05 14:55 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4c57cfe8.887b0e0a.2f79.4772@mx.google.com>
2010-08-03 8:21 ` [PATCH] [Bug 16494] NFS client over TCP hangs due to packet loss David Miller
[not found] ` <20100803.012144.267950450.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2010-08-03 9:11 ` Andrew Morton
[not found] ` <20100803021110.f0b3877b.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2010-08-03 10:25 ` Andy Chittenden
[not found] ` <4C57EE9A.7040308-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2010-08-05 14:55 ` Andy Chittenden [this message]
[not found] ` <4c5ad0d6.42ecd80a.47d7.0dfc-ATjtLOhZ0NVl57MIdRCFDg@public.gmane.org>
2010-08-05 19:50 ` Trond Myklebust
[not found] ` <1281037822.2948.49.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
2010-08-06 9:30 ` Andy Chittenden
2010-08-09 9:27 ` Andy Chittenden
2010-08-09 16:55 ` Trond Myklebust
[not found] ` <1281372927.8950.3.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
2010-08-10 8:40 ` Andy Chittenden
2018-06-19 21:56 ` Joe Perches
2018-06-20 16:40 ` Andy C
2010-08-03 8:14 Andy Chittenden
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