mirror of https://gitee.com/openkylin/linux.git
158 lines
3.6 KiB
C
158 lines
3.6 KiB
C
/* AFS fileserver list management.
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*
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* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include "internal.h"
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void afs_put_serverlist(struct afs_net *net, struct afs_server_list *slist)
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{
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int i;
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if (slist && refcount_dec_and_test(&slist->usage)) {
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for (i = 0; i < slist->nr_servers; i++) {
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afs_put_cb_interest(net, slist->servers[i].cb_interest);
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afs_put_server(net, slist->servers[i].server);
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}
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kfree(slist);
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}
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}
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/*
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* Build a server list from a VLDB record.
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*/
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struct afs_server_list *afs_alloc_server_list(struct afs_cell *cell,
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struct key *key,
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struct afs_vldb_entry *vldb,
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u8 type_mask)
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{
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struct afs_server_list *slist;
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struct afs_server *server;
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int ret = -ENOMEM, nr_servers = 0, i, j;
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for (i = 0; i < vldb->nr_servers; i++)
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if (vldb->fs_mask[i] & type_mask)
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nr_servers++;
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slist = kzalloc(sizeof(struct afs_server_list) +
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sizeof(struct afs_server_entry) * nr_servers,
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GFP_KERNEL);
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if (!slist)
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goto error;
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refcount_set(&slist->usage, 1);
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rwlock_init(&slist->lock);
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/* Make sure a records exists for each server in the list. */
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for (i = 0; i < vldb->nr_servers; i++) {
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if (!(vldb->fs_mask[i] & type_mask))
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continue;
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server = afs_lookup_server(cell, key, &vldb->fs_server[i]);
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if (IS_ERR(server)) {
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ret = PTR_ERR(server);
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if (ret == -ENOENT ||
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ret == -ENOMEDIUM)
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continue;
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goto error_2;
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}
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/* Insertion-sort by UUID */
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for (j = 0; j < slist->nr_servers; j++)
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if (memcmp(&slist->servers[j].server->uuid,
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&server->uuid,
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sizeof(server->uuid)) >= 0)
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break;
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if (j < slist->nr_servers) {
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if (slist->servers[j].server == server) {
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afs_put_server(cell->net, server);
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continue;
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}
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memmove(slist->servers + j + 1,
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slist->servers + j,
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(slist->nr_servers - j) * sizeof(struct afs_server_entry));
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}
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slist->servers[j].server = server;
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slist->nr_servers++;
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}
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if (slist->nr_servers == 0) {
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ret = -EDESTADDRREQ;
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goto error_2;
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}
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return slist;
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error_2:
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afs_put_serverlist(cell->net, slist);
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error:
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return ERR_PTR(ret);
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}
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/*
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* Copy the annotations from an old server list to its potential replacement.
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*/
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bool afs_annotate_server_list(struct afs_server_list *new,
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struct afs_server_list *old)
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{
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struct afs_server *cur;
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int i, j;
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if (old->nr_servers != new->nr_servers)
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goto changed;
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for (i = 0; i < old->nr_servers; i++)
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if (old->servers[i].server != new->servers[i].server)
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goto changed;
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return false;
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changed:
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/* Maintain the same current server as before if possible. */
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cur = old->servers[old->index].server;
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for (j = 0; j < new->nr_servers; j++) {
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if (new->servers[j].server == cur) {
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new->index = j;
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break;
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}
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}
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/* Keep the old callback interest records where possible so that we
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* maintain callback interception.
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*/
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i = 0;
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j = 0;
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while (i < old->nr_servers && j < new->nr_servers) {
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if (new->servers[j].server == old->servers[i].server) {
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struct afs_cb_interest *cbi = old->servers[i].cb_interest;
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if (cbi) {
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new->servers[j].cb_interest = cbi;
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refcount_inc(&cbi->usage);
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}
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i++;
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j++;
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continue;
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}
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if (new->servers[j].server < old->servers[i].server) {
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j++;
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continue;
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}
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i++;
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continue;
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}
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return true;
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}
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