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/* 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 (slist && 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);
rwlock_init(&slist->lock);
/* 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 ||
ret == -ENOMEDIUM)
continue;
goto error_2;
}
/* Insertion-sort by UUID */
for (j = 0; j < slist->nr_servers; j++)
if (memcmp(&slist->servers[j].server->uuid,
&server->uuid,
sizeof(server->uuid)) >= 0)
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 preferred server as before if possible. */
cur = old->servers[old->preferred].server;
for (j = 0; j < new->nr_servers; j++) {
if (new->servers[j].server == cur) {
new->preferred = 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;
}
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