On Wed, Oct 30, 2013 at 04:02:47PM +0200, Benny Halevy wrote:
> On 2013-10-29 16:46, J. Bruce Fields wrote:
> > On Tue, Oct 29, 2013 at 11:39:04AM +0200, Benny Halevy wrote:
> >> Access to dp->dl_perclnt must be synchronized by the recall_lock
> >
> > Are you sure? recall_lock is for stuff that's needed in the delegation
> > break callback (nfsd_break_deleg_cb() and any of the subsequent callback
> > handling). I don't think that includes dl_perclnt.
>
> I was mislead by the fact that destroy_client and nfs4_state_shutdown_net
> care to acquire the recall_lock for traversing the clp->cl_delegations
> and nn->del_recall_lru lists, respectively.
>
> Now nfs4_state_shutdown_net, although its comment says it should be
> called with the state lock held (SHOULD or should, or should it be MUST? :)
> It doesn't seem like nfsd_shutdown_net acquires the state lock.
Good point.
> Therefore, we either need to grab the state lock in nfs4_state_shutdown_net
> which adds yet another problem to fix,
That sounds simplest as the short-term fix.... What problem do you see?
--b.
commit 2c9407ae694dad8a1ad6394d9bf6077024b9fae7
Author: J. Bruce Fields <bfields@xxxxxxxxxx>
Date: Wed Oct 30 10:33:09 2013 -0400
nfsd4: nfsd_shutdown_net needs state lock
A comment claims the caller should take it, but that's not being done.
Note we don't want it around the cancel_delayed_work_sync since that may
wait on work which holds the client lock.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 21eb678..e03e8ef 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5124,7 +5124,6 @@ out_recovery:
return ret;
}
-/* should be called with the state lock held */
void
nfs4_state_shutdown_net(struct net *net)
{
@@ -5135,6 +5134,7 @@ nfs4_state_shutdown_net(struct net *net)
cancel_delayed_work_sync(&nn->laundromat_work);
locks_end_grace(&nn->nfsd4_manager);
+ nfs4_lock_state();
INIT_LIST_HEAD(&reaplist);
spin_lock(&recall_lock);
list_for_each_safe(pos, next, &nn->del_recall_lru) {
@@ -5149,6 +5149,7 @@ nfs4_state_shutdown_net(struct net *net)
nfsd4_client_tracking_exit(net);
nfs4_state_destroy_net(net);
+ nfs4_unlock_state();
}
void
--
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