NFSD: Skip sending CB_RECALL_ANY when the backchannel isn't up

commit 8a388c1fabeb6606e16467b23242416c0dbeffad upstream.

NFSD sends CB_RECALL_ANY to clients when the server is low on
memory or that client has a large number of delegations outstanding.

We've seen cases where NFSD attempts to send CB_RECALL_ANY requests
to disconnected clients, and gets confused. These calls never go
anywhere if a backchannel transport to the target client isn't
available. Before the server can send any backchannel operation, the
client has to connect first and then do a BIND_CONN_TO_SESSION.

This patch doesn't address the root cause of the confusion, but
there's no need to queue up these optional operations if they can't
go anywhere.

Fixes: 44df6f439a17 ("NFSD: add delegation reaper to react to low memory condition")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Chuck Lever 2025-01-14 17:09:24 -05:00 committed by Greg Kroah-Hartman
parent d96587cc93
commit 14a6b65c83

View File

@ -6247,14 +6247,19 @@ deleg_reaper(struct nfsd_net *nn)
spin_lock(&nn->client_lock);
list_for_each_safe(pos, next, &nn->client_lru) {
clp = list_entry(pos, struct nfs4_client, cl_lru);
if (clp->cl_state != NFSD4_ACTIVE ||
list_empty(&clp->cl_delegations) ||
atomic_read(&clp->cl_delegs_in_recall) ||
test_bit(NFSD4_CLIENT_CB_RECALL_ANY, &clp->cl_flags) ||
(ktime_get_boottime_seconds() -
clp->cl_ra_time < 5)) {
if (clp->cl_state != NFSD4_ACTIVE)
continue;
if (list_empty(&clp->cl_delegations))
continue;
if (atomic_read(&clp->cl_delegs_in_recall))
continue;
if (test_bit(NFSD4_CLIENT_CB_RECALL_ANY, &clp->cl_flags))
continue;
if (ktime_get_boottime_seconds() - clp->cl_ra_time < 5)
continue;
if (clp->cl_cb_state != NFSD4_CB_UP)
continue;
}
list_add(&clp->cl_ra_cblist, &cblist);
/* release in nfsd4_cb_recall_any_release */