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 } 21 kfree(slist); 22 } 23 } 24 25 /* 26 * Build a server list from a VLDB record. 27 */ 28 struct afs_server_list *afs_alloc_server_list(struct afs_cell *cell, 29 struct key *key, 30 struct afs_vldb_entry *vldb, 31 u8 type_mask) 32 { 33 struct afs_server_list *slist; 34 struct afs_server *server; 35 int ret = -ENOMEM, nr_servers = 0, i, j; 36 37 for (i = 0; i < vldb->nr_servers; i++) 38 if (vldb->fs_mask[i] & type_mask) 39 nr_servers++; 40 41 slist = kzalloc(struct_size(slist, servers, nr_servers), GFP_KERNEL); 42 if (!slist) 43 goto error; 44 45 refcount_set(&slist->usage, 1); 46 rwlock_init(&slist->lock); 47 48 /* Make sure a records exists for each server in the list. */ 49 for (i = 0; i < vldb->nr_servers; i++) { 50 if (!(vldb->fs_mask[i] & type_mask)) 51 continue; 52 53 server = afs_lookup_server(cell, key, &vldb->fs_server[i]); 54 if (IS_ERR(server)) { 55 ret = PTR_ERR(server); 56 if (ret == -ENOENT || 57 ret == -ENOMEDIUM) 58 continue; 59 goto error_2; 60 } 61 62 /* Insertion-sort by UUID */ 63 for (j = 0; j < slist->nr_servers; j++) 64 if (memcmp(&slist->servers[j].server->uuid, 65 &server->uuid, 66 sizeof(server->uuid)) >= 0) 67 break; 68 if (j < slist->nr_servers) { 69 if (slist->servers[j].server == server) { 70 afs_put_server(cell->net, server); 71 continue; 72 } 73 74 memmove(slist->servers + j + 1, 75 slist->servers + j, 76 (slist->nr_servers - j) * sizeof(struct afs_server_entry)); 77 } 78 79 slist->servers[j].server = server; 80 slist->nr_servers++; 81 } 82 83 if (slist->nr_servers == 0) { 84 ret = -EDESTADDRREQ; 85 goto error_2; 86 } 87 88 return slist; 89 90 error_2: 91 afs_put_serverlist(cell->net, slist); 92 error: 93 return ERR_PTR(ret); 94 } 95 96 /* 97 * Copy the annotations from an old server list to its potential replacement. 98 */ 99 bool afs_annotate_server_list(struct afs_server_list *new, 100 struct afs_server_list *old) 101 { 102 struct afs_server *cur; 103 int i, j; 104 105 if (old->nr_servers != new->nr_servers) 106 goto changed; 107 108 for (i = 0; i < old->nr_servers; i++) 109 if (old->servers[i].server != new->servers[i].server) 110 goto changed; 111 112 return false; 113 114 changed: 115 /* Maintain the same preferred server as before if possible. */ 116 cur = old->servers[old->preferred].server; 117 for (j = 0; j < new->nr_servers; j++) { 118 if (new->servers[j].server == cur) { 119 new->preferred = j; 120 break; 121 } 122 } 123 124 /* Keep the old callback interest records where possible so that we 125 * maintain callback interception. 126 */ 127 i = 0; 128 j = 0; 129 while (i < old->nr_servers && j < new->nr_servers) { 130 if (new->servers[j].server == old->servers[i].server) { 131 struct afs_cb_interest *cbi = old->servers[i].cb_interest; 132 if (cbi) { 133 new->servers[j].cb_interest = cbi; 134 refcount_inc(&cbi->usage); 135 } 136 i++; 137 j++; 138 continue; 139 } 140 141 if (new->servers[j].server < old->servers[i].server) { 142 j++; 143 continue; 144 } 145 146 i++; 147 continue; 148 } 149 150 return true; 151 } 152