afs: Fix afs_cell records to always have a VL server list record

Fix it such that afs_cell records always have a VL server list record
attached, even if it's a dummy one, so that various checks can be removed.
Signed-off-by: David Howells <dhowells@redhat.com>

fs/afs/cell.c

@@ -123,6 +123,7 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net,
 				       const char *name, unsigned int namelen,
 				       const char *addresses)
 {
+	struct afs_vlserver_list *vllist;
 	struct afs_cell *cell;
 	int i, ret;
 
@@ -157,12 +158,10 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net,
 	rwlock_init(&cell->proc_lock);
 	rwlock_init(&cell->vl_servers_lock);
 
-	/* Fill in the VL server list if we were given a list of addresses to
-	 * use.
+	/* Provide a VL server list, filling it in if we were given a list of
+	 * addresses to use.
 	 */
 	if (addresses) {
-		struct afs_vlserver_list *vllist;
-
 		vllist = afs_parse_text_addrs(net,
 					      addresses, strlen(addresses), ':',
 					      VL_SERVICE, AFS_VL_PORT);
@@ -171,19 +170,24 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net,
 			goto parse_failed;
 		}
 
-		rcu_assign_pointer(cell->vl_servers, vllist);
 		cell->dns_expiry = TIME64_MAX;
-		__clear_bit(AFS_CELL_FL_NO_LOOKUP_YET, &cell->flags);
 	} else {
+		ret = -ENOMEM;
+		vllist = afs_alloc_vlserver_list(0);
+		if (!vllist)
+			goto error;
 		cell->dns_expiry = ktime_get_real_seconds();
 	}
 
+	rcu_assign_pointer(cell->vl_servers, vllist);
+
 	_leave(" = %p", cell);
 	return cell;
 
 parse_failed:
 	if (ret == -EINVAL)
 		printk(KERN_ERR "kAFS: bad VL server IP address\n");
+error:
 	kfree(cell);
 	_leave(" = %d", ret);
 	return ERR_PTR(ret);
@@ -410,8 +414,7 @@ static void afs_update_cell(struct afs_cell *cell)
 		cell->dns_expiry = expiry;
 		write_unlock(&cell->vl_servers_lock);
 
-		if (old)
-			afs_put_vlserverlist(cell->net, old);
+		afs_put_vlserverlist(cell->net, old);
 	}
 
 	if (test_and_clear_bit(AFS_CELL_FL_NO_LOOKUP_YET, &cell->flags))

fs/afs/proc.c

@@ -53,7 +53,7 @@ static int afs_proc_cells_show(struct seq_file *m, void *v)
 	seq_printf(m, "%3u %6lld %2u %s\n",
 		   atomic_read(&cell->usage),
 		   cell->dns_expiry - ktime_get_real_seconds(),
-		   vllist ? vllist->nr_servers : 0,
+		   vllist->nr_servers,
 		   cell->name);
 	return 0;
 }
@@ -296,8 +296,8 @@ static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v)
 
 	if (v == SEQ_START_TOKEN) {
 		seq_printf(m, "# source %s, status %s\n",
-			   dns_record_sources[vllist->source],
-			   dns_lookup_statuses[vllist->status]);
+			   dns_record_sources[vllist ? vllist->source : 0],
+			   dns_lookup_statuses[vllist ? vllist->status : 0]);
 		return 0;
 	}
 
@@ -336,7 +336,7 @@ static void *afs_proc_cell_vlservers_start(struct seq_file *m, loff_t *_pos)
 	if (pos == 0)
 		return SEQ_START_TOKEN;
 
-	if (!vllist || pos - 1 >= vllist->nr_servers)
+	if (pos - 1 >= vllist->nr_servers)
 		return NULL;
 
 	return &vllist->servers[pos - 1];

fs/afs/vl_list.c

@@ -232,18 +232,16 @@ struct afs_vlserver_list *afs_extract_vlserver_list(struct afs_cell *cell,
 		if (bs.status > NR__dns_lookup_status)
 			bs.status = NR__dns_lookup_status;
 
+		/* See if we can update an old server record */
 		server = NULL;
-		if (previous) {
-			/* See if we can update an old server record */
-			for (i = 0; i < previous->nr_servers; i++) {
-				struct afs_vlserver *p = previous->servers[i].server;
-
-				if (p->name_len == bs.name_len &&
-				    p->port == bs.port &&
-				    strncasecmp(b, p->name, bs.name_len) == 0) {
-					server = afs_get_vlserver(p);
-					break;
-				}
+		for (i = 0; i < previous->nr_servers; i++) {
+			struct afs_vlserver *p = previous->servers[i].server;
+
+			if (p->name_len == bs.name_len &&
+			    p->port == bs.port &&
+			    strncasecmp(b, p->name, bs.name_len) == 0) {
+				server = afs_get_vlserver(p);
+				break;
 			}
 		}
 

fs/afs/vl_rotate.c

@@ -55,7 +55,7 @@ static bool afs_start_vl_iteration(struct afs_vl_cursor *vc)
 		rcu_dereference_protected(cell->vl_servers,
 					  lockdep_is_held(&cell->vl_servers_lock)));
 	read_unlock(&cell->vl_servers_lock);
-	if (!vc->server_list || !vc->server_list->nr_servers)
+	if (!vc->server_list->nr_servers)
 		return false;
 
 	vc->untried = (1UL << vc->server_list->nr_servers) - 1;