> >> I would expect the timeouts to have changed due to the NFSv4 trunking detection (which is
> >> exactly why it is wrong to rely on the kernel timeouts here anyway), but I would not expect
> >> the kernel to never time out at all.
> > It appears it started with 3.13 kernels... The above stack is from a 3.14-ish client.
> >
>
> Which patch caused the behaviour to change?
561ec1603171cd9b38dcf6cac53e8710f437a48d is the first bad commit
commit 561ec1603171cd9b38dcf6cac53e8710f437a48d
Author: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Date: Thu Sep 26 15:22:45 2013 -0400
SUNRPC: call_connect_status should recheck bind and connect status on error
Currently, we go directly to call_transmit which sends us to call_status
on error. If we know that the connect attempt failed, we should rather
just jump straight back to call_bind and call_connect.
Ditto for EAGAIN, except do not delay.
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
If I revert that commit from mainline (which may be a completely bogus thing
to do) then mainline works (at least for this specific simple test).
(The revert required some wiggling - I'll include it below).
To be precise, the test is to try to mount
mount server:/path /mnt
from a server which has run
rpc.nfsd -T -N4
"success" is getting periodic messages:
mount.nfs: trying text-based options 'retry=1,vers=4,addr=10.0.10.2,clientaddr=10.0.10.1'
mount.nfs: mount(2): Connection refused
"failure" is not getting those messages.
There is another change though.
For the commit above I don't not get "Connection refused", but after 2
minutes I get
mount.nfs: mount(2): Connection timed out
With mainline, it waits forever.
I did a second git bisect for this change and found
2118071d3b0d57a03fad77885f4fdc364798aa87 is the first bad commit
commit 2118071d3b0d57a03fad77885f4fdc364798aa87
Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date: Tue Dec 31 13:22:59 2013 -0500
SUNRPC: Report connection error values to rpc_tasks on the pending queue
Currently we only report EAGAIN, which is not descriptive enough for
softconn tasks.
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
From this commit, a mount attempt which is getting connections denied will
block indefinitely.
Hope that is helpful.
NeilBrown
This is the revert that I mentioned - just for completeness.
From 9c1462ff54fcc2adc79c825b867c32c19e30a9a7 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@xxxxxxx>
Date: Thu, 13 Mar 2014 11:38:54 +1100
Subject: [PATCH] Revert "SUNRPC: call_connect_status should recheck bind and
connect status on error"
This reverts commit 561ec1603171cd9b38dcf6cac53e8710f437a48d.
Conflicts:
net/sunrpc/clnt.c
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 0edada973434..ba0cd114f0e1 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1796,7 +1796,6 @@ call_connect_status(struct rpc_task *task)
dprint_status(task);
trace_rpc_connect_status(task, status);
- task->tk_status = 0;
switch (status) {
/* if soft mounted, test if we've timed out */
case -ETIMEDOUT:
@@ -1805,16 +1804,14 @@ call_connect_status(struct rpc_task *task)
case -ECONNREFUSED:
case -ECONNRESET:
case -ECONNABORTED:
- case -ENETUNREACH:
case -EHOSTUNREACH:
- /* retry with existing socket, after a delay */
- rpc_delay(task, 3*HZ);
+ case -ENETUNREACH:
if (RPC_IS_SOFTCONN(task))
break;
- case -EAGAIN:
- task->tk_action = call_bind;
- return;
+ /* retry with existing socket, after a delay */
case 0:
+ case -EAGAIN:
+ task->tk_status = 0;
clnt->cl_stats->netreconn++;
task->tk_action = call_transmit;
return;
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