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-rw-r--r--fs/afs/server_list.c153
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;
+}