nfsd4: fix mixed 4.0/4.1 handling, 4.1 reboot

Instead of failing to find client entries which don't match the
minorversion, we should be finding them, then either erroring out or
expiring them as appropriate.

This also fixes a problem which would cause the 4.1 server to fail to
recognize clients after a second reboot.
Reported-by: Casey Bodley <cbodley@citi.umich.edu>
Reviewed-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4recover.c

@@ -302,7 +302,6 @@ purge_old(struct dentry *parent, struct dentry *child)
 {
 	int status;
 
-	/* note: we currently use this path only for minorversion 0 */
 	if (nfs4_has_reclaimed_state(child->d_name.name, false))
 		return 0;
 

fs/nfsd/nfs4state.c

@@ -1134,39 +1134,30 @@ find_unconfirmed_client(clientid_t *clid)
 	return NULL;
 }
 
-/*
- * FIXME: we need to unify the clientid namespaces for nfsv4.x
- * and correctly deal with client upgrade/downgrade in EXCHANGE_ID
- * and SET_CLIENTID{,_CONFIRM}
- */
 static bool clp_used_exchangeid(struct nfs4_client *clp)
 {
 	return clp->cl_exchange_flags != 0;
-}
+} 
 
 static struct nfs4_client *
-find_confirmed_client_by_str(const char *dname, unsigned int hashval,
-			     bool use_exchange_id)
+find_confirmed_client_by_str(const char *dname, unsigned int hashval)
 {
 	struct nfs4_client *clp;
 
 	list_for_each_entry(clp, &conf_str_hashtbl[hashval], cl_strhash) {
-		if (same_name(clp->cl_recdir, dname) &&
-		    clp_used_exchangeid(clp) == use_exchange_id)
+		if (same_name(clp->cl_recdir, dname))
 			return clp;
 	}
 	return NULL;
 }
 
 static struct nfs4_client *
-find_unconfirmed_client_by_str(const char *dname, unsigned int hashval,
-			       bool use_exchange_id)
+find_unconfirmed_client_by_str(const char *dname, unsigned int hashval)
 {
 	struct nfs4_client *clp;
 
 	list_for_each_entry(clp, &unconf_str_hashtbl[hashval], cl_strhash) {
-		if (same_name(clp->cl_recdir, dname) &&
-		    clp_used_exchangeid(clp) == use_exchange_id)
+		if (same_name(clp->cl_recdir, dname))
 			return clp;
 	}
 	return NULL;
@@ -1357,8 +1348,12 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
 	nfs4_lock_state();
 	status = nfs_ok;
 
-	conf = find_confirmed_client_by_str(dname, strhashval, true);
+	conf = find_confirmed_client_by_str(dname, strhashval);
 	if (conf) {
+		if (!clp_used_exchangeid(conf)) {
+			status = nfserr_clid_inuse; /* XXX: ? */
+			goto out;
+		}
 		if (!same_verf(&verf, &conf->cl_verifier)) {
 			/* 18.35.4 case 8 */
 			if (exid->flags & EXCHGID4_FLAG_UPD_CONFIRMED_REC_A) {
@@ -1399,7 +1394,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
 		goto out;
 	}
 
-	unconf  = find_unconfirmed_client_by_str(dname, strhashval, true);
+	unconf  = find_unconfirmed_client_by_str(dname, strhashval);
 	if (unconf) {
 		/*
 		 * Possible retry or client restart.  Per 18.35.4 case 4,
@@ -1799,10 +1794,12 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	strhashval = clientstr_hashval(dname);
 
 	nfs4_lock_state();
-	conf = find_confirmed_client_by_str(dname, strhashval, false);
+	conf = find_confirmed_client_by_str(dname, strhashval);
 	if (conf) {
 		/* RFC 3530 14.2.33 CASE 0: */
 		status = nfserr_clid_inuse;
+		if (clp_used_exchangeid(conf))
+			goto out;
 		if (!same_creds(&conf->cl_cred, &rqstp->rq_cred)) {
 			char addr_str[INET6_ADDRSTRLEN];
 			rpc_ntop((struct sockaddr *) &conf->cl_addr, addr_str,
@@ -1817,7 +1814,7 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	 * has a description of SETCLIENTID request processing consisting
 	 * of 5 bullet points, labeled as CASE0 - CASE4 below.
 	 */
-	unconf = find_unconfirmed_client_by_str(dname, strhashval, false);
+	unconf = find_unconfirmed_client_by_str(dname, strhashval);
 	status = nfserr_resource;
 	if (!conf) {
 		/*
@@ -1962,7 +1959,7 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
 			unsigned int hash =
 				clientstr_hashval(unconf->cl_recdir);
 			conf = find_confirmed_client_by_str(unconf->cl_recdir,
-							    hash, false);
+							    hash);
 			if (conf) {
 				nfsd4_remove_clid_dir(conf);
 				expire_client(conf);
@@ -4106,7 +4103,7 @@ nfs4_has_reclaimed_state(const char *name, bool use_exchange_id)
 	unsigned int strhashval = clientstr_hashval(name);
 	struct nfs4_client *clp;
 
-	clp = find_confirmed_client_by_str(name, strhashval, use_exchange_id);
+	clp = find_confirmed_client_by_str(name, strhashval);
 	return clp ? 1 : 0;
 }