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 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_put_cb_interest(net, slist->servers[i].cb_interest); 19 afs_put_server(net, slist->servers[i].server, 20 afs_server_trace_put_slist); 21 } 22 kfree(slist); 23 } 24 } 25 26 /* 27 * Build a server list from a VLDB record. 28 */ 29 struct afs_server_list *afs_alloc_server_list(struct afs_cell *cell, 30 struct key *key, 31 struct afs_vldb_entry *vldb, 32 u8 type_mask) 33 { 34 struct afs_server_list *slist; 35 struct afs_server *server; 36 int ret = -ENOMEM, nr_servers = 0, i, j; 37 38 for (i = 0; i < vldb->nr_servers; i++) 39 if (vldb->fs_mask[i] & type_mask) 40 nr_servers++; 41 42 slist = kzalloc(struct_size(slist, servers, nr_servers), GFP_KERNEL); 43 if (!slist) 44 goto error; 45 46 refcount_set(&slist->usage, 1); 47 rwlock_init(&slist->lock); 48 49 /* Make sure a records exists for each server in the list. */ 50 for (i = 0; i < vldb->nr_servers; i++) { 51 if (!(vldb->fs_mask[i] & type_mask)) 52 continue; 53 54 server = afs_lookup_server(cell, key, &vldb->fs_server[i]); 55 if (IS_ERR(server)) { 56 ret = PTR_ERR(server); 57 if (ret == -ENOENT || 58 ret == -ENOMEDIUM) 59 continue; 60 goto error_2; 61 } 62 63 /* Insertion-sort by UUID */ 64 for (j = 0; j < slist->nr_servers; j++) 65 if (memcmp(&slist->servers[j].server->uuid, 66 &server->uuid, 67 sizeof(server->uuid)) >= 0) 68 break; 69 if (j < slist->nr_servers) { 70 if (slist->servers[j].server == server) { 71 afs_put_server(cell->net, server, 72 afs_server_trace_put_slist_isort); 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 preferred server as before if possible. */ 118 cur = old->servers[old->preferred].server; 119 for (j = 0; j < new->nr_servers; j++) { 120 if (new->servers[j].server == cur) { 121 new->preferred = 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 } 154