On 9/22/21 2:14 PM, J. Bruce Fields wrote:
On Thu, Sep 16, 2021 at 02:22:11PM -0400, Dai Ngo wrote:
@@ -2389,6 +2395,10 @@ static int client_info_show(struct seq_file *m, void *v)
seq_puts(m, "status: confirmed\n");
else
seq_puts(m, "status: unconfirmed\n");
+ seq_printf(m, "courtesy client: %s\n",
+ test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags) ? "yes" : "no");
+ seq_printf(m, "last renew: %lld secs\n",
I'd rather keep any units to the left of the colon. Also, "last renew"
suggests to me that it's the absolute time of the last renew. Maybe
"seconds since last renew:" ?
will fix in v4.
+ ktime_get_boottime_seconds() - clp->cl_time);
seq_printf(m, "name: ");
seq_quote_mem(m, clp->cl_name.data, clp->cl_name.len);
seq_printf(m, "\nminor version: %d\n", clp->cl_minorversion);
@@ -4652,6 +4662,42 @@ static void nfsd_break_one_deleg(struct nfs4_delegation *dp)
nfsd4_run_cb(&dp->dl_recall);
}
+/*
+ * If the conflict happens due to a NFSv4 request then check for
+ * courtesy client and set rq_conflict_client so that upper layer
+ * can destroy the conflict client and retry the call.
+ */
+static bool
+nfsd_check_courtesy_client(struct nfs4_delegation *dp)
+{
+ struct svc_rqst *rqst;
+ struct nfs4_client *clp = dp->dl_recall.cb_clp;
+ struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
+ bool ret = false;
+
+ if (!i_am_nfsd()) {
+ if (test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags)) {
+ set_bit(NFSD4_DESTROY_COURTESY_CLIENT, &clp->cl_flags);
+ mod_delayed_work(laundry_wq, &nn->laundromat_work, 0);
+ return true;
+ }
+ return false;
+ }
+ rqst = kthread_data(current);
+ if (rqst->rq_prog != NFS_PROGRAM || rqst->rq_vers < 4)
+ return false;
+ rqst->rq_conflict_client = NULL;
+
+ spin_lock(&nn->client_lock);
+ if (test_bit(NFSD4_COURTESY_CLIENT, &clp->cl_flags) &&
+ !mark_client_expired_locked(clp)) {
+ rqst->rq_conflict_client = clp;
+ ret = true;
+ }
+ spin_unlock(&nn->client_lock);
Check whether this is safe; I think the flc_lock may be taken inside of
this lock elsewhere, resulting in a potential deadlock?
rqst doesn't need any locking as it's only being used by this thread, so
it's the client expiration stuff that's the problem, I guess.
mark_client_expired_locked needs to acquire cl_lock. I think the lock
ordering is ok, client_lock -> cl_lock. nfsd4_exchange_id uses this
lock ordering.
I will submit v4 patch with the fix in client_info_show and also new code
for handling NFSv4 share reservation conflicts with courtesy clients.
Thanks Bruce,
-Dai
--b.
