On 05/20/11 12:40, Trond Myklebust wrote:
On Fri, 2011-05-20 at 12:29 -0700, Harry Edmon wrote:
On 05/20/11 10:52, Trond Myklebust wrote:
On Fri, 2011-05-20 at 13:26 -0400, Dr. J. Bruce Fields wrote:
On Fri, May 20, 2011 at 09:20:47AM -0700, Harry Edmon wrote:
On 05/16/11 13:53, Dr. J. Bruce Fields wrote:
Hm, so the renews all have clid 465ccc4d09000000, and the reads all have
a stateid (0, 465ccc4dc24c0a0000000000).
So the first 4 bytes matching just tells me both were handed out by the
same server instance (so there was no server reboot in between); there's
no way for me to tell whether they really belong to the same client.
The server does assume that any stateid from the current server instance
that no longer exists in its table is expired. I believe that's
correct, given a correctly functioning client, but perhaps I'm missing a
case.
--b.
I am very appreciative of the quick initial comments I receive from
all of you on my NFS problem. I notice that there has been silence
on the problem since the 16th, so I assume that either this is a
hard bug to track down or you have been busy with higher priority
tasks. Is there anything I can do to help develop a solution to
this problem?
Well, the only candidate explanation for the problem is that my
assumption--that any time the server gets a stateid from the current
boot instance that it doesn't recognize as an active stateid, it is safe
for the server to return EXPIRED--is wrong.
I don't immediately see why it's wrong, and based on the silence nobody
else does either, but I'm not 100% convinced I'm right either.
So one approach might be to add server code that makes a better effort
to return EXPIRED only when we're sure it's a stateid from an expired
client, and see if that solves your problem.
Remind me, did you have an easy way to reproduce your problem?
My silence is simply because I'm mystified as to how this can happen.
Patching for it is trivial (see below).
When the server tells us that our lease is expired, the normal behaviour
for the client is to re-establish the lease, and then proceed to recover
all known stateids. I don't see how we can 'miss' a stateid that then
needs to be recovered afterwards...
Cheers
Trond
8<----------------------------------------------------------------------------
From 920ddb153f28717be363f6e87dde24ef2a8d0ce2 Mon Sep 17 00:00:00 2001
From: Trond Myklebust<Trond.Myklebust@xxxxxxxxxx>
Date: Fri, 20 May 2011 13:44:02 -0400
Subject: [PATCH] NFSv4: Handle expired stateids when the lease is still valid
Currently, if the server returns NFS4ERR_EXPIRED in reply to a READ or
WRITE, but the RENEW test determines that the lease is still active, we
fail to recover and end up looping forever in a READ/WRITE + RENEW death
spiral.
Signed-off-by: Trond Myklebust<Trond.Myklebust@xxxxxxxxxx>
---
fs/nfs/nfs4proc.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index cf1b339..d0e15db 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -267,9 +267,11 @@ static int nfs4_handle_exception(struct nfs_server *server, int errorcode, struc
break;
nfs4_schedule_stateid_recovery(server, state);
goto wait_on_recovery;
+ case -NFS4ERR_EXPIRED:
+ if (state != NULL)
+ nfs4_schedule_stateid_recovery(server, state);
case -NFS4ERR_STALE_STATEID:
case -NFS4ERR_STALE_CLIENTID:
- case -NFS4ERR_EXPIRED:
nfs4_schedule_lease_recovery(clp);
goto wait_on_recovery;
#if defined(CONFIG_NFS_V4_1)
@@ -3670,9 +3672,11 @@ nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server,
break;
nfs4_schedule_stateid_recovery(server, state);
goto wait_on_recovery;
+ case -NFS4ERR_EXPIRED:
+ if (state != NULL)
+ nfs4_schedule_stateid_recovery(server, state);
case -NFS4ERR_STALE_STATEID:
case -NFS4ERR_STALE_CLIENTID:
- case -NFS4ERR_EXPIRED:
nfs4_schedule_lease_recovery(clp);
goto wait_on_recovery;
#if defined(CONFIG_NFS_V4_1)
@@ -4543,6 +4547,7 @@ int nfs4_lock_delegation_recall(struct nfs4_state *state, struct file_lock *fl)
case -ESTALE:
goto out;
case -NFS4ERR_EXPIRED:
+ nfs4_schedule_stateid_recovery(server, state);
case -NFS4ERR_STALE_CLIENTID:
case -NFS4ERR_STALE_STATEID:
nfs4_schedule_lease_recovery(server->nfs_client);
I installed this patch on my client, and now I am seeing the state
manager appear in the process accounting file about once a minute rather
that the constant respawning I saw earlier. Is once a minute normal, or
is there still a problem?
Once a minute is rather unusual... What kind of server are you running
against?
If it is a Linux server, what is the value contained in the virtual file
"/proc/fs/nfsd/nfsv4leasetime" ?
Same as before - Debian Squeeze running 2.6.38.6. The value of
/proc/fs/nfsd/nfsv4leasetime is 90 and is not something I changed.
--
Dr. Harry Edmon E-MAIL: harry@xxxxxx
206-543-0547 FAX: 206-543-0308 harry@xxxxxxxxxxxxxxxxxxxx
Director of IT, College of the Environment and
Director of Computing, Dept of Atmospheric Sciences
University of Washington, Box 351640, Seattle, WA 98195-1640
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