Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:27656 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756549AbaCRTBp (ORCPT ); Tue, 18 Mar 2014 15:01:45 -0400 Message-ID: <532897DE.6060204@RedHat.com> Date: Tue, 18 Mar 2014 15:00:46 -0400 From: Steve Dickson MIME-Version: 1.0 To: Trond Myklebust CC: linux-nfs@vger.kernel.org Subject: Re: [PATCH 1/2] SUNRPC: Ensure that call_connect times out correctly References: <1395081645-11906-1-git-send-email-trond.myklebust@primarydata.com> <53286A9D.2020007@RedHat.com> <362845B0-35A4-4DDF-96F6-42582D66334B@primarydata.com> <53288146.4010601@RedHat.com> <1395168308.11244.3.camel@leira.trondhjem.org> In-Reply-To: <1395168308.11244.3.camel@leira.trondhjem.org> Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On 03/18/2014 02:45 PM, Trond Myklebust wrote: > On Tue, 2014-03-18 at 13:24 -0400, Steve Dickson wrote: >> >> On 03/18/2014 11:58 AM, Trond Myklebust wrote: >>> >>> On Mar 18, 2014, at 11:47, Steve Dickson wrote: >>> >>>> Hey, >>>> >>>> On 03/17/2014 02:40 PM, Trond Myklebust wrote: >>>>> When the server is unavailable due to a networking error, etc, we want >>>>> the RPC client to respect the timeout delays when attempting to reconnect. >>>>> >>>>> Fixes: 561ec1603171 (SUNRPC: call_connect_status should recheck bind..) >>>>> Signed-off-by: Trond Myklebust >>>>> --- >>>>> net/sunrpc/clnt.c | 8 +++----- >>>>> 1 file changed, 3 insertions(+), 5 deletions(-) >>>>> >>>>> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c >>>>> index 0edada973434..f22d3a115fda 100644 >>>>> --- a/net/sunrpc/clnt.c >>>>> +++ b/net/sunrpc/clnt.c >>>>> @@ -1798,10 +1798,6 @@ call_connect_status(struct rpc_task *task) >>>>> trace_rpc_connect_status(task, status); >>>>> task->tk_status = 0; >>>>> switch (status) { >>>>> - /* if soft mounted, test if we've timed out */ >>>>> - case -ETIMEDOUT: >>>>> - task->tk_action = call_timeout; >>>>> - return; >>>>> case -ECONNREFUSED: >>>>> case -ECONNRESET: >>>>> case -ECONNABORTED: >>>>> @@ -1812,7 +1808,9 @@ call_connect_status(struct rpc_task *task) >>>>> if (RPC_IS_SOFTCONN(task)) >>>>> break; >>>>> case -EAGAIN: >>>>> - task->tk_action = call_bind; >>>>> + case -ETIMEDOUT: >>>>> + /* Check if we've timed out before looping back to call_bind */ >>>>> + task->tk_action = call_timeout; >>>>> return; >>>>> case 0: >>>>> clnt->cl_stats->netreconn++; >>>>> >>>> How is this support to work if the trunking code still ignores timeouts? >>>> >>>> [ 2076.045176] NFS: nfs4_discover_server_trunking after status -110, retrying >>> >>> The above patch fixes the regression that Neil tracked down in Linux 3.12, and that >>> affects the generic RPC handling of soft timeouts. >>> >>> The trunking code's handling of ETIMEDOUT has been there since Linux 3.7 >>> and hasn’t changed, so I really don’t see how it can have worked at one time before 3.12. >> Maybe it been broken that long.... :-) >> >> But here is the obvious loop that stop that hangs a mount forever: >> >> #8 [ffff88007a22b7e8] rpc_call_sync at ffffffffa0220210 [sunrpc] >> #9 [ffff88007a22b840] nfs4_proc_setclientid at ffffffffa0505c49 [nfsv4] >> #10 [ffff88007a22b988] nfs40_discover_server_trunking at ffffffffa0514489 [nfsv4] >> #11 [ffff88007a22b9d0] nfs4_discover_server_trunking at ffffffffa0516f2d [nfsv4] >> #12 [ffff88007a22ba28] nfs4_init_client at ffffffffa051e9a4 [nfsv4] >> #13 [ffff88007a22bb20] nfs_get_client at ffffffffa04bd6ba [nfs] >> #14 [ffff88007a22bb80] nfs4_set_client at ffffffffa051dfb0 [nfsv4] >> #15 [ffff88007a22bc00] nfs4_create_server at ffffffffa051f4ce [nfsv4] >> #16 [ffff88007a22bc88] nfs4_remote_mount at ffffffffa051790e [nfsv4] >> #17 [ffff88007a22bcb0] mount_fs at ffffffff811b3dd9 >> >> The SETCLIENT times out >> NFS call setclientid auth=UNIX, 'Linux NFSv4.0 10.19.60.77/10.19.60.33 tcp' >> NFS reply setclientid: -110 >> >> The nfs4_discover_server_trunking() retries >> NFS: nfs4_discover_server_trunking after status -110, retrying >> >> The happens when there server is down and so the connections >> fail with ECONNREFUSED: >> RPC: 2 call_connect_status (status -111) >> >> The mount system call never times out in which it did in the past. > > Why should a mount system call time out other than perhaps in the case > of a soft mount? > So the mount can go in background. As you know the -o bg is used in the /etc/fstab so the boot does not get hung up with downed servers. That's how it always worked... steved.