> -----Original Message-----
> From: Myklebust, Trond
> Sent: Friday, January 22, 2010 10:47 AM
> To: Batsakis, Alexandros
> Cc: linux-nfs@xxxxxxxxxxxxxxx; Myklebust, Trond
> Subject: Re: [PATCH 1/1] nfs: fix race between renewd, umount, and the
> state manager in V4.1
>
> On Thu, 2010-01-21 at 20:51 -0800, Alexandros Batsakis wrote:
>
> > struct rpc_cred *nfs4_get_setclientid_cred(struct nfs_client *clp)
> > @@ -878,7 +888,11 @@ void nfs4_schedule_state_manager(struct
> nfs_client *clp)
> > if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) !=
> 0)
> > return;
> > __module_get(THIS_MODULE);
> > - atomic_inc(&clp->cl_count);
> > + if (!atomic_inc_not_zero(&clp->cl_count)) {
> > + nfs4_clear_state_manager_bit(clp);
> > + module_put(THIS_MODULE);
> > + return;
> > + }
>
> The use of atomic_inc_not_zero() should not be necessary here. Anybody
> who is calling this function without holding a reference to clp is
> doing
> something fundamentally wrong.
Agreed, but how can we enforce this (especially with asynchronous RPC) ?
For example what will happen if _during_ umount (after nfs_put_client()), an NFS call that was sleeping e.g. waiting for the server to come up, reaches the server and the response causes the state manager to start ?
Any ideas ?
-a
>
> Trond
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