[PATCH RFC v14 07/10] NFSD: Update find_client_in_id_table() to handle courtesy clients

[Dai Ngo <dai.ngo@xxxxxxxxxx>]

Update find_client_in_id_table to:
 . skip client with CLIENT_EXPIRED; discarded courtesy client
 . if courtesy client was found then clear CLIENT_COURTESY and set
   CLIENT_RECONNECTED flag so callers can take appropriate action.

Update find_confirmed_client to discard courtesy client.
Update lookup_clientid to call find_client_in_id_table directly.
Update set_client to create client record for courtesy client.
Update find_cpntf_state to discard courtesy client.

Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
---
 fs/nfsd/nfs4state.c | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 5cef1a78cc28..6e3ca0ea4f28 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2915,6 +2915,19 @@ find_client_in_id_table(struct list_head *tbl, clientid_t *clid, bool sessions)
 		if (same_clid(&clp->cl_clientid, clid)) {
 			if ((bool)clp->cl_minorversion != sessions)
 				return NULL;
+
+			/* need to sync with thread resolving lock/deleg conflict */
+			clear_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
+			spin_lock(&clp->cl_cs_lock);
+			if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
+				spin_unlock(&clp->cl_cs_lock);
+				continue;
+			}
+			if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
+				clear_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags);
+				set_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags);
+			}
+			spin_unlock(&clp->cl_cs_lock);
 			renew_client_locked(clp);
 			return clp;
 		}
@@ -2922,6 +2935,7 @@ find_client_in_id_table(struct list_head *tbl, clientid_t *clid, bool sessions)
 	return NULL;
 }
 
+
 static void
 nfsd4_discard_courtesy_clnt(struct nfs4_client *clp)
 {
@@ -2934,9 +2948,15 @@ static struct nfs4_client *
 find_confirmed_client(clientid_t *clid, bool sessions, struct nfsd_net *nn)
 {
 	struct list_head *tbl = nn->conf_id_hashtbl;
+	struct nfs4_client *clp;
 
 	lockdep_assert_held(&nn->client_lock);
-	return find_client_in_id_table(tbl, clid, sessions);
+	clp = find_client_in_id_table(tbl, clid, sessions);
+	if (clp && test_bit(NFSD4_CLIENT_RECONNECTED, &clp->cl_flags)) {
+		nfsd4_discard_courtesy_clnt(clp);
+		clp = NULL;
+	}
+	return clp;
 }
 
 static struct nfs4_client *
@@ -4867,9 +4887,10 @@ static struct nfs4_client *lookup_clientid(clientid_t *clid, bool sessions,
 						struct nfsd_net *nn)
 {
 	struct nfs4_client *found;
+	struct list_head *tbl = nn->conf_id_hashtbl;
 
 	spin_lock(&nn->client_lock);
-	found = find_confirmed_client(clid, sessions, nn);
+	found = find_client_in_id_table(tbl, clid, sessions);
 	if (found)
 		atomic_inc(&found->cl_rpc_users);
 	spin_unlock(&nn->client_lock);
@@ -4894,6 +4915,8 @@ static __be32 set_client(clientid_t *clid,
 	cstate->clp = lookup_clientid(clid, false, nn);
 	if (!cstate->clp)
 		return nfserr_expired;
+	if (test_bit(NFSD4_CLIENT_RECONNECTED, &cstate->clp->cl_flags))
+		nfsd4_client_record_create(cstate->clp);
 	return nfs_ok;
 }
 
@@ -6222,6 +6245,13 @@ static __be32 find_cpntf_state(struct nfsd_net *nn, stateid_t *st,
 	found = lookup_clientid(&cps->cp_p_clid, true, nn);
 	if (!found)
 		goto out;
+	if (test_bit(NFSD4_CLIENT_RECONNECTED, &found->cl_flags)) {
+		nfsd4_discard_courtesy_clnt(found);
+		if (atomic_dec_and_lock(&found->cl_rpc_users,
+				&nn->client_lock))
+			spin_unlock(&nn->client_lock);
+		goto out;
+	}
 
 	*stid = find_stateid_by_type(found, &cps->cp_p_stateid,
 			NFS4_DELEG_STID|NFS4_OPEN_STID|NFS4_LOCK_STID);
-- 
2.9.5