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1 | /* AFS fileserver list management. |
2 | * | |
3 | * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/kernel.h> | |
13 | #include <linux/slab.h> | |
14 | #include "internal.h" | |
15 | ||
16 | void afs_put_serverlist(struct afs_net *net, struct afs_server_list *slist) | |
17 | { | |
18 | int i; | |
19 | ||
0fafdc9f | 20 | if (slist && refcount_dec_and_test(&slist->usage)) { |
d2ddc776 DH |
21 | for (i = 0; i < slist->nr_servers; i++) { |
22 | afs_put_cb_interest(net, slist->servers[i].cb_interest); | |
23 | afs_put_server(net, slist->servers[i].server); | |
24 | } | |
25 | kfree(slist); | |
26 | } | |
27 | } | |
28 | ||
29 | /* | |
30 | * Build a server list from a VLDB record. | |
31 | */ | |
32 | struct afs_server_list *afs_alloc_server_list(struct afs_cell *cell, | |
33 | struct key *key, | |
34 | struct afs_vldb_entry *vldb, | |
35 | u8 type_mask) | |
36 | { | |
37 | struct afs_server_list *slist; | |
38 | struct afs_server *server; | |
39 | int ret = -ENOMEM, nr_servers = 0, i, j; | |
40 | ||
41 | for (i = 0; i < vldb->nr_servers; i++) | |
42 | if (vldb->fs_mask[i] & type_mask) | |
43 | nr_servers++; | |
44 | ||
45 | slist = kzalloc(sizeof(struct afs_server_list) + | |
46 | sizeof(struct afs_server_entry) * nr_servers, | |
47 | GFP_KERNEL); | |
48 | if (!slist) | |
49 | goto error; | |
50 | ||
51 | refcount_set(&slist->usage, 1); | |
52 | ||
53 | /* Make sure a records exists for each server in the list. */ | |
54 | for (i = 0; i < vldb->nr_servers; i++) { | |
55 | if (!(vldb->fs_mask[i] & type_mask)) | |
56 | continue; | |
57 | ||
58 | server = afs_lookup_server(cell, key, &vldb->fs_server[i]); | |
59 | if (IS_ERR(server)) { | |
60 | ret = PTR_ERR(server); | |
61 | if (ret == -ENOENT) | |
62 | continue; | |
63 | goto error_2; | |
64 | } | |
65 | ||
66 | /* Insertion-sort by server pointer */ | |
67 | for (j = 0; j < slist->nr_servers; j++) | |
68 | if (slist->servers[j].server >= server) | |
69 | break; | |
70 | if (j < slist->nr_servers) { | |
71 | if (slist->servers[j].server == server) { | |
72 | afs_put_server(cell->net, server); | |
73 | continue; | |
74 | } | |
75 | ||
76 | memmove(slist->servers + j + 1, | |
77 | slist->servers + j, | |
78 | (slist->nr_servers - j) * sizeof(struct afs_server_entry)); | |
79 | } | |
80 | ||
81 | slist->servers[j].server = server; | |
82 | slist->nr_servers++; | |
83 | } | |
84 | ||
85 | if (slist->nr_servers == 0) { | |
86 | ret = -EDESTADDRREQ; | |
87 | goto error_2; | |
88 | } | |
89 | ||
90 | return slist; | |
91 | ||
92 | error_2: | |
93 | afs_put_serverlist(cell->net, slist); | |
94 | error: | |
95 | return ERR_PTR(ret); | |
96 | } | |
97 | ||
98 | /* | |
99 | * Copy the annotations from an old server list to its potential replacement. | |
100 | */ | |
101 | bool afs_annotate_server_list(struct afs_server_list *new, | |
102 | struct afs_server_list *old) | |
103 | { | |
104 | struct afs_server *cur; | |
105 | int i, j; | |
106 | ||
107 | if (old->nr_servers != new->nr_servers) | |
108 | goto changed; | |
109 | ||
110 | for (i = 0; i < old->nr_servers; i++) | |
111 | if (old->servers[i].server != new->servers[i].server) | |
112 | goto changed; | |
113 | ||
114 | return false; | |
115 | ||
116 | changed: | |
117 | /* Maintain the same current server as before if possible. */ | |
118 | cur = old->servers[old->index].server; | |
119 | for (j = 0; j < new->nr_servers; j++) { | |
120 | if (new->servers[j].server == cur) { | |
121 | new->index = j; | |
122 | break; | |
123 | } | |
124 | } | |
125 | ||
126 | /* Keep the old callback interest records where possible so that we | |
127 | * maintain callback interception. | |
128 | */ | |
129 | i = 0; | |
130 | j = 0; | |
131 | while (i < old->nr_servers && j < new->nr_servers) { | |
132 | if (new->servers[j].server == old->servers[i].server) { | |
133 | struct afs_cb_interest *cbi = old->servers[i].cb_interest; | |
134 | if (cbi) { | |
135 | new->servers[j].cb_interest = cbi; | |
136 | refcount_inc(&cbi->usage); | |
137 | } | |
138 | i++; | |
139 | j++; | |
140 | continue; | |
141 | } | |
142 | ||
143 | if (new->servers[j].server < old->servers[i].server) { | |
144 | j++; | |
145 | continue; | |
146 | } | |
147 | ||
148 | i++; | |
149 | continue; | |
150 | } | |
151 | ||
152 | return true; | |
153 | } |