Re: [PATCH] NFS4: Fix v4.0 client state corruption when mount

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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..

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?

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@xxxxxxxxxx>
---
 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





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