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_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 */ 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 */ 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