1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* AFS fileserver list management.
3 *
4 * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #include <linux/kernel.h>
9 #include <linux/slab.h>
10 #include "internal.h"
11
afs_put_serverlist(struct afs_net * net,struct afs_server_list * slist)12 void afs_put_serverlist(struct afs_net *net, struct afs_server_list *slist)
13 {
14 int i;
15
16 if (slist && refcount_dec_and_test(&slist->usage)) {
17 for (i = 0; i < slist->nr_servers; i++)
18 afs_unuse_server(net, slist->servers[i].server,
19 afs_server_trace_put_slist);
20 kfree(slist);
21 }
22 }
23
24 /*
25 * Build a server list from a VLDB record.
26 */
afs_alloc_server_list(struct afs_cell * cell,struct key * key,struct afs_vldb_entry * vldb,u8 type_mask)27 struct afs_server_list *afs_alloc_server_list(struct afs_cell *cell,
28 struct key *key,
29 struct afs_vldb_entry *vldb,
30 u8 type_mask)
31 {
32 struct afs_server_list *slist;
33 struct afs_server *server;
34 int ret = -ENOMEM, nr_servers = 0, i, j;
35
36 for (i = 0; i < vldb->nr_servers; i++)
37 if (vldb->fs_mask[i] & type_mask)
38 nr_servers++;
39
40 slist = kzalloc(struct_size(slist, servers, nr_servers), GFP_KERNEL);
41 if (!slist)
42 goto error;
43
44 refcount_set(&slist->usage, 1);
45 rwlock_init(&slist->lock);
46
47 for (i = 0; i < AFS_MAXTYPES; i++)
48 slist->vids[i] = vldb->vid[i];
49
50 /* Make sure a records exists for each server in the list. */
51 for (i = 0; i < vldb->nr_servers; i++) {
52 if (!(vldb->fs_mask[i] & type_mask))
53 continue;
54
55 server = afs_lookup_server(cell, key, &vldb->fs_server[i],
56 vldb->addr_version[i]);
57 if (IS_ERR(server)) {
58 ret = PTR_ERR(server);
59 if (ret == -ENOENT ||
60 ret == -ENOMEDIUM)
61 continue;
62 goto error_2;
63 }
64
65 /* Insertion-sort by UUID */
66 for (j = 0; j < slist->nr_servers; j++)
67 if (memcmp(&slist->servers[j].server->uuid,
68 &server->uuid,
69 sizeof(server->uuid)) >= 0)
70 break;
71 if (j < slist->nr_servers) {
72 if (slist->servers[j].server == server) {
73 afs_put_server(cell->net, server,
74 afs_server_trace_put_slist_isort);
75 continue;
76 }
77
78 memmove(slist->servers + j + 1,
79 slist->servers + j,
80 (slist->nr_servers - j) * sizeof(struct afs_server_entry));
81 }
82
83 slist->servers[j].server = server;
84 slist->nr_servers++;
85 }
86
87 if (slist->nr_servers == 0) {
88 ret = -EDESTADDRREQ;
89 goto error_2;
90 }
91
92 return slist;
93
94 error_2:
95 afs_put_serverlist(cell->net, slist);
96 error:
97 return ERR_PTR(ret);
98 }
99
100 /*
101 * Copy the annotations from an old server list to its potential replacement.
102 */
afs_annotate_server_list(struct afs_server_list * new,struct afs_server_list * old)103 bool afs_annotate_server_list(struct afs_server_list *new,
104 struct afs_server_list *old)
105 {
106 struct afs_server *cur;
107 int i, j;
108
109 if (old->nr_servers != new->nr_servers)
110 goto changed;
111
112 for (i = 0; i < old->nr_servers; i++)
113 if (old->servers[i].server != new->servers[i].server)
114 goto changed;
115
116 return false;
117
118 changed:
119 /* Maintain the same preferred server as before if possible. */
120 cur = old->servers[old->preferred].server;
121 for (j = 0; j < new->nr_servers; j++) {
122 if (new->servers[j].server == cur) {
123 new->preferred = j;
124 break;
125 }
126 }
127
128 return true;
129 }
130
