From: "zhangxiaoxu (A)" <zhangxiaoxu5@huawei.com>
To: Benjamin Coddington <bcodding@redhat.com>
Cc: <trond.myklebust@hammerspace.com>, <anna.schumaker@netapp.com>,
<linux-nfs@vger.kernel.org>
Subject: Re: [PATCH] NFS4: Fix v4.0 client state corruption when mount
Date: Thu, 7 Nov 2019 10:34:23 +0800 [thread overview]
Message-ID: <6348ccfd-4a61-5e82-fd2a-03b2c18fe220@huawei.com> (raw)
In-Reply-To: <21D6F3D9-C1B6-4F5C-98A0-87B067C6E198@redhat.com>
在 2019/11/7 0:47, Benjamin Coddington 写道:
> Hi ZhangXiaoxu,
>
> I'm having a bit of trouble with this fix (which went upstream in
> f02f3755dbd14fb935d24b14650fff9ba92243b8).
>
> Since this change, my client calls SETCLIENTID/SETCLIENTID_CONFIRM twice in
> quick succession on mount, and the second SETCLIENTID_CONFIRM sent by the state
> manager can sometimes have the same verifier sent back by the first
> SETCLIENTID's response. I think we're missing a memory barrier somewhere..
nfs40_discover_server_trunking
nfs4_proc_setclientid # the first time
after nfs4_schedule_state_manager, the state manager:
nfs4_run_state_manager
nfs4_state_manager
# 'nfs4_alloc_client' init state to NFS4CLNT_LEASE_EXPIRED
nfs4_reclaim_lease
nfs4_establish_lease
nfs4_init_clientid
nfs4_proc_setclientid # the second time.
>
> But, I do not understand how the client was able to corrupt the state before
> this patch, and I don't understand how the patch fixes state corruption.
>
> Can anyone enlighten me as to how we were corrupting state here?
when 'nfs4_alloc_client', the client state initialized with 'NFS4CLNT_LEASE_EXPIRED',
So, we should recover it when the client init.
After the first setclientid, maybe we should clear the 'NFS4CLNT_LEASE_EXPIRED', then
the state manager won't be called it again.
>
> Ben
>
> On 5 May 2019, at 23:57, ZhangXiaoxu wrote:
>
>> stat command with soft mount never return after server is stopped.
>>
>> When alloc a new client, the state of the client will be set to
>> NFS4CLNT_LEASE_EXPIRED.
>>
>> When the server is stopped, the state manager will work, and accord
>> the state to recover. But the state is NFS4CLNT_LEASE_EXPIRED, it
>> will drain the slot table and lead other task to wait queue, until
>> the client recovered. Then the stat command is hung.
>>
>> When discover server trunking, the client will renew the lease,
>> but check the client state, it lead the client state corruption.
>>
>> So, we need to call state manager to recover it when detect server
>> ip trunking.
>>
>> Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
>> ---
>> fs/nfs/nfs4state.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
>> index 3de3647..f502f1c 100644
>> --- a/fs/nfs/nfs4state.c
>> +++ b/fs/nfs/nfs4state.c
>> @@ -159,6 +159,10 @@ int nfs40_discover_server_trunking(struct nfs_client *clp,
>> /* Sustain the lease, even if it's empty. If the clientid4
>> * goes stale it's of no use for trunking discovery. */
>> nfs4_schedule_state_renewal(*result);
>> +
>> + /* If the client state need to recover, do it. */
>> + if (clp->cl_state)
>> + nfs4_schedule_state_manager(clp);
>> }
>> out:
>> return status;
>> --
>> 2.7.4
>
>
> .
next prev parent reply other threads:[~2019-11-07 2:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-06 3:57 [PATCH] NFS4: Fix v4.0 client state corruption when mount ZhangXiaoxu
2019-05-13 1:48 ` zhangxiaoxu (A)
2019-11-06 16:47 ` Benjamin Coddington
2019-11-07 2:34 ` zhangxiaoxu (A) [this message]
2019-11-07 13:25 ` Benjamin Coddington
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