5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chuck Lever chuck.lever@oracle.com
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 --- fs/nfsd/nfs4state.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)
--- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -6250,14 +6250,19 @@ 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 */