1 files changed, 153 insertions, 0 deletions
diff --git a/fs/afs/server_list.c b/fs/afs/server_list.c
new file mode 100644
index 000000000000..26bad7032bba
--- /dev/null
+++ b/fs/afs/server_list.c
@@ -0,0 +1,153 @@
+/* AFS fileserver list management.
+ *
+ * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+void afs_put_serverlist(struct afs_net *net, struct afs_server_list *slist)
+{
+	int i;
+
+	if (refcount_dec_and_test(&slist->usage)) {
+		for (i = 0; i < slist->nr_servers; i++) {
+			afs_put_cb_interest(net, slist->servers[i].cb_interest);
+			afs_put_server(net, slist->servers[i].server);
+		}
+		kfree(slist);
+	}
+}
+
+/*
+ * Build a server list from a VLDB record.
+ */
+struct afs_server_list *afs_alloc_server_list(struct afs_cell *cell,
+					      struct key *key,
+					      struct afs_vldb_entry *vldb,
+					      u8 type_mask)
+{
+	struct afs_server_list *slist;
+	struct afs_server *server;
+	int ret = -ENOMEM, nr_servers = 0, i, j;
+
+	for (i = 0; i < vldb->nr_servers; i++)
+		if (vldb->fs_mask[i] & type_mask)
+			nr_servers++;
+
+	slist = kzalloc(sizeof(struct afs_server_list) +
+			sizeof(struct afs_server_entry) * nr_servers,
+			GFP_KERNEL);
+	if (!slist)
+		goto error;
+
+	refcount_set(&slist->usage, 1);
+
+	/* Make sure a records exists for each server in the list. */
+	for (i = 0; i < vldb->nr_servers; i++) {
+		if (!(vldb->fs_mask[i] & type_mask))
+			continue;
+
+		server = afs_lookup_server(cell, key, &vldb->fs_server[i]);
+		if (IS_ERR(server)) {
+			ret = PTR_ERR(server);
+			if (ret == -ENOENT)
+				continue;
+			goto error_2;
+		}
+
+		/* Insertion-sort by server pointer */
+		for (j = 0; j < slist->nr_servers; j++)
+			if (slist->servers[j].server >= server)
+				break;
+		if (j < slist->nr_servers) {
+			if (slist->servers[j].server == server) {
+				afs_put_server(cell->net, server);
+				continue;
+			}
+
+			memmove(slist->servers + j + 1,
+				slist->servers + j,
+				(slist->nr_servers - j) * sizeof(struct afs_server_entry));
+		}
+
+		slist->servers[j].server = server;
+		slist->nr_servers++;
+	}
+
+	if (slist->nr_servers == 0) {
+		ret = -EDESTADDRREQ;
+		goto error_2;
+	}
+
+	return slist;
+
+error_2:
+	afs_put_serverlist(cell->net, slist);
+error:
+	return ERR_PTR(ret);
+}
+
+/*
+ * Copy the annotations from an old server list to its potential replacement.
+ */
+bool afs_annotate_server_list(struct afs_server_list *new,
+			      struct afs_server_list *old)
+{
+	struct afs_server *cur;
+	int i, j;
+
+	if (old->nr_servers != new->nr_servers)
+		goto changed;
+
+	for (i = 0; i < old->nr_servers; i++)
+		if (old->servers[i].server != new->servers[i].server)
+			goto changed;
+
+	return false;
+
+changed:
+	/* Maintain the same current server as before if possible. */
+	cur = old->servers[old->index].server;
+	for (j = 0; j < new->nr_servers; j++) {
+		if (new->servers[j].server == cur) {
+			new->index = j;
+			break;
+		}
+	}
+
+	/* Keep the old callback interest records where possible so that we
+	 * maintain callback interception.
+	 */
+	i = 0;
+	j = 0;
+	while (i < old->nr_servers && j < new->nr_servers) {
+		if (new->servers[j].server == old->servers[i].server) {
+			struct afs_cb_interest *cbi = old->servers[i].cb_interest;
+			if (cbi) {
+				new->servers[j].cb_interest = cbi;
+				refcount_inc(&cbi->usage);
+			}
+			i++;
+			j++;
+			continue;
+		}
+
+		if (new->servers[j].server < old->servers[i].server) {
+			j++;
+			continue;
+		}
+
+		i++;
+		continue;
+	}
+
+	return true;
+}