server_list.c 2.9 KB

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