nfs41: implement DESTROY_CLIENTID operation

According to rfc5661 18.50, implement DESTROY_CLIENTID operation.
Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4proc.c

@@ -1645,7 +1645,7 @@ static struct nfsd4_operation nfsd4_ops[] = {
 		.op_name = "OP_SEQUENCE",
 	},
 	[OP_DESTROY_CLIENTID] = {
-		.op_func = NULL,
+		.op_func = (nfsd4op_func)nfsd4_destroy_clientid,
 		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP
 				| OP_MODIFIES_SOMETHING,
 		.op_name = "OP_DESTROY_CLIENTID",

fs/nfsd/nfs4state.c

@@ -1962,6 +1962,50 @@ nfsd4_sequence(struct svc_rqst *rqstp,
 	return status;
 }
 
+static inline bool has_resources(struct nfs4_client *clp)
+{
+	return !list_empty(&clp->cl_openowners)
+		|| !list_empty(&clp->cl_delegations)
+		|| !list_empty(&clp->cl_sessions);
+}
+
+__be32
+nfsd4_destroy_clientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, struct nfsd4_destroy_clientid *dc)
+{
+	struct nfs4_client *conf, *unconf, *clp;
+	int status = 0;
+
+	nfs4_lock_state();
+	unconf = find_unconfirmed_client(&dc->clientid);
+	conf = find_confirmed_client(&dc->clientid);
+
+	if (conf) {
+		clp = conf;
+
+		if (!is_client_expired(conf) && has_resources(conf)) {
+			status = nfserr_clientid_busy;
+			goto out;
+		}
+
+		/* rfc5661 18.50.3 */
+		if (cstate->session && conf == cstate->session->se_client) {
+			status = nfserr_clientid_busy;
+			goto out;
+		}
+	} else if (unconf)
+		clp = unconf;
+	else {
+		status = nfserr_stale_clientid;
+		goto out;
+	}
+
+	expire_client(clp);
+out:
+	nfs4_unlock_state();
+	dprintk("%s return %d\n", __func__, ntohl(status));
+	return status;
+}
+
 __be32
 nfsd4_reclaim_complete(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, struct nfsd4_reclaim_complete *rc)
 {

fs/nfsd/nfs4xdr.c

@@ -1417,6 +1417,16 @@ nfsd4_decode_test_stateid(struct nfsd4_compoundargs *argp, struct nfsd4_test_sta
 	goto out;
 }
 
+static __be32 nfsd4_decode_destroy_clientid(struct nfsd4_compoundargs *argp, struct nfsd4_destroy_clientid *dc)
+{
+	DECODE_HEAD;
+
+	READ_BUF(8);
+	COPYMEM(&dc->clientid, 8);
+
+	DECODE_TAIL;
+}
+
 static __be32 nfsd4_decode_reclaim_complete(struct nfsd4_compoundargs *argp, struct nfsd4_reclaim_complete *rc)
 {
 	DECODE_HEAD;
@@ -1538,7 +1548,7 @@ static nfsd4_dec nfsd41_dec_ops[] = {
 	[OP_SET_SSV]		= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_TEST_STATEID]	= (nfsd4_dec)nfsd4_decode_test_stateid,
 	[OP_WANT_DELEGATION]	= (nfsd4_dec)nfsd4_decode_notsupp,
-	[OP_DESTROY_CLIENTID]	= (nfsd4_dec)nfsd4_decode_notsupp,
+	[OP_DESTROY_CLIENTID]	= (nfsd4_dec)nfsd4_decode_destroy_clientid,
 	[OP_RECLAIM_COMPLETE]	= (nfsd4_dec)nfsd4_decode_reclaim_complete,
 };
 

fs/nfsd/xdr4.h

@@ -398,6 +398,10 @@ struct nfsd4_destroy_session {
 	struct nfs4_sessionid	sessionid;
 };
 
+struct nfsd4_destroy_clientid {
+	clientid_t clientid;
+};
+
 struct nfsd4_reclaim_complete {
 	u32 rca_one_fs;
 };
@@ -552,6 +556,7 @@ extern __be32 nfsd4_sequence(struct svc_rqst *,
 extern __be32 nfsd4_destroy_session(struct svc_rqst *,
 		struct nfsd4_compound_state *,
 		struct nfsd4_destroy_session *);
+extern __be32 nfsd4_destroy_clientid(struct svc_rqst *, struct nfsd4_compound_state *, struct nfsd4_destroy_clientid *);
 __be32 nfsd4_reclaim_complete(struct svc_rqst *, struct nfsd4_compound_state *, struct nfsd4_reclaim_complete *);
 extern __be32 nfsd4_process_open1(struct nfsd4_compound_state *,
 		struct nfsd4_open *open);