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![David Howells](/assets/img/avatar_default.png)
Don't give an assertion failure on unpurgeable afs_server records - which kills the thread - but rather emit a trace line when we are purging a record (which only happens during network namespace removal or rmmod) and print a notice of the problem. Signed-off-by: David Howells <dhowells@redhat.com>
713 lines
18 KiB
C
713 lines
18 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* AFS server record management
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*
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* Copyright (C) 2002, 2007 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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#include <linux/sched.h>
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#include <linux/slab.h>
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#include "afs_fs.h"
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#include "internal.h"
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#include "protocol_yfs.h"
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static unsigned afs_server_gc_delay = 10; /* Server record timeout in seconds */
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static atomic_t afs_server_debug_id;
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static struct afs_server *afs_maybe_use_server(struct afs_server *,
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enum afs_server_trace);
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static void __afs_put_server(struct afs_net *, struct afs_server *);
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/*
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* Find a server by one of its addresses.
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*/
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struct afs_server *afs_find_server(struct afs_net *net,
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const struct sockaddr_rxrpc *srx)
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{
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const struct afs_addr_list *alist;
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struct afs_server *server = NULL;
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unsigned int i;
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int seq = 0, diff;
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rcu_read_lock();
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do {
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if (server)
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afs_unuse_server_notime(net, server, afs_server_trace_put_find_rsq);
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server = NULL;
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read_seqbegin_or_lock(&net->fs_addr_lock, &seq);
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if (srx->transport.family == AF_INET6) {
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const struct sockaddr_in6 *a = &srx->transport.sin6, *b;
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hlist_for_each_entry_rcu(server, &net->fs_addresses6, addr6_link) {
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alist = rcu_dereference(server->addresses);
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for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
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b = &alist->addrs[i].transport.sin6;
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diff = ((u16 __force)a->sin6_port -
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(u16 __force)b->sin6_port);
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if (diff == 0)
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diff = memcmp(&a->sin6_addr,
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&b->sin6_addr,
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sizeof(struct in6_addr));
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if (diff == 0)
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goto found;
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}
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}
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} else {
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const struct sockaddr_in *a = &srx->transport.sin, *b;
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hlist_for_each_entry_rcu(server, &net->fs_addresses4, addr4_link) {
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alist = rcu_dereference(server->addresses);
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for (i = 0; i < alist->nr_ipv4; i++) {
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b = &alist->addrs[i].transport.sin;
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diff = ((u16 __force)a->sin_port -
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(u16 __force)b->sin_port);
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if (diff == 0)
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diff = ((u32 __force)a->sin_addr.s_addr -
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(u32 __force)b->sin_addr.s_addr);
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if (diff == 0)
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goto found;
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}
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}
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}
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server = NULL;
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continue;
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found:
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server = afs_maybe_use_server(server, afs_server_trace_get_by_addr);
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} while (need_seqretry(&net->fs_addr_lock, seq));
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done_seqretry(&net->fs_addr_lock, seq);
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rcu_read_unlock();
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return server;
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}
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/*
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* Look up a server by its UUID and mark it active.
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*/
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struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uuid)
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{
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struct afs_server *server = NULL;
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struct rb_node *p;
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int diff, seq = 0;
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_enter("%pU", uuid);
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do {
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/* Unfortunately, rbtree walking doesn't give reliable results
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* under just the RCU read lock, so we have to check for
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* changes.
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*/
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if (server)
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afs_unuse_server(net, server, afs_server_trace_put_uuid_rsq);
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server = NULL;
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read_seqbegin_or_lock(&net->fs_lock, &seq);
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p = net->fs_servers.rb_node;
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while (p) {
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server = rb_entry(p, struct afs_server, uuid_rb);
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diff = memcmp(uuid, &server->uuid, sizeof(*uuid));
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if (diff < 0) {
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p = p->rb_left;
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} else if (diff > 0) {
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p = p->rb_right;
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} else {
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afs_use_server(server, afs_server_trace_get_by_uuid);
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break;
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}
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server = NULL;
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}
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} while (need_seqretry(&net->fs_lock, seq));
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done_seqretry(&net->fs_lock, seq);
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_leave(" = %p", server);
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return server;
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}
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/*
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* Install a server record in the namespace tree. If there's a clash, we stick
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* it into a list anchored on whichever afs_server struct is actually in the
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* tree.
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*/
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static struct afs_server *afs_install_server(struct afs_cell *cell,
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struct afs_server *candidate)
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{
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const struct afs_addr_list *alist;
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struct afs_server *server, *next;
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struct afs_net *net = cell->net;
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struct rb_node **pp, *p;
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int diff;
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_enter("%p", candidate);
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write_seqlock(&net->fs_lock);
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/* Firstly install the server in the UUID lookup tree */
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pp = &net->fs_servers.rb_node;
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p = NULL;
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while (*pp) {
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p = *pp;
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_debug("- consider %p", p);
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server = rb_entry(p, struct afs_server, uuid_rb);
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diff = memcmp(&candidate->uuid, &server->uuid, sizeof(uuid_t));
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if (diff < 0) {
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pp = &(*pp)->rb_left;
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} else if (diff > 0) {
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pp = &(*pp)->rb_right;
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} else {
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if (server->cell == cell)
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goto exists;
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/* We have the same UUID representing servers in
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* different cells. Append the new server to the list.
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*/
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for (;;) {
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next = rcu_dereference_protected(
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server->uuid_next,
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lockdep_is_held(&net->fs_lock.lock));
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if (!next)
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break;
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server = next;
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}
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rcu_assign_pointer(server->uuid_next, candidate);
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candidate->uuid_prev = server;
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server = candidate;
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goto added_dup;
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}
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}
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server = candidate;
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rb_link_node(&server->uuid_rb, p, pp);
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rb_insert_color(&server->uuid_rb, &net->fs_servers);
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hlist_add_head_rcu(&server->proc_link, &net->fs_proc);
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added_dup:
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write_seqlock(&net->fs_addr_lock);
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alist = rcu_dereference_protected(server->addresses,
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lockdep_is_held(&net->fs_addr_lock.lock));
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/* Secondly, if the server has any IPv4 and/or IPv6 addresses, install
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* it in the IPv4 and/or IPv6 reverse-map lists.
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*
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* TODO: For speed we want to use something other than a flat list
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* here; even sorting the list in terms of lowest address would help a
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* bit, but anything we might want to do gets messy and memory
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* intensive.
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*/
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if (alist->nr_ipv4 > 0)
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hlist_add_head_rcu(&server->addr4_link, &net->fs_addresses4);
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if (alist->nr_addrs > alist->nr_ipv4)
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hlist_add_head_rcu(&server->addr6_link, &net->fs_addresses6);
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write_sequnlock(&net->fs_addr_lock);
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exists:
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afs_get_server(server, afs_server_trace_get_install);
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write_sequnlock(&net->fs_lock);
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return server;
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}
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/*
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* Allocate a new server record and mark it active.
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*/
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static struct afs_server *afs_alloc_server(struct afs_cell *cell,
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const uuid_t *uuid,
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struct afs_addr_list *alist)
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{
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struct afs_server *server;
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struct afs_net *net = cell->net;
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_enter("");
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server = kzalloc(sizeof(struct afs_server), GFP_KERNEL);
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if (!server)
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goto enomem;
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atomic_set(&server->ref, 1);
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atomic_set(&server->active, 1);
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server->debug_id = atomic_inc_return(&afs_server_debug_id);
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RCU_INIT_POINTER(server->addresses, alist);
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server->addr_version = alist->version;
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server->uuid = *uuid;
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rwlock_init(&server->fs_lock);
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init_waitqueue_head(&server->probe_wq);
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INIT_LIST_HEAD(&server->probe_link);
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spin_lock_init(&server->probe_lock);
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server->cell = cell;
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server->rtt = UINT_MAX;
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afs_inc_servers_outstanding(net);
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trace_afs_server(server, 1, 1, afs_server_trace_alloc);
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_leave(" = %p", server);
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return server;
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enomem:
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_leave(" = NULL [nomem]");
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return NULL;
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}
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/*
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* Look up an address record for a server
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*/
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static struct afs_addr_list *afs_vl_lookup_addrs(struct afs_cell *cell,
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struct key *key, const uuid_t *uuid)
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{
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struct afs_vl_cursor vc;
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struct afs_addr_list *alist = NULL;
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int ret;
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ret = -ERESTARTSYS;
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if (afs_begin_vlserver_operation(&vc, cell, key)) {
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while (afs_select_vlserver(&vc)) {
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if (test_bit(AFS_VLSERVER_FL_IS_YFS, &vc.server->flags))
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alist = afs_yfsvl_get_endpoints(&vc, uuid);
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else
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alist = afs_vl_get_addrs_u(&vc, uuid);
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}
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ret = afs_end_vlserver_operation(&vc);
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}
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return ret < 0 ? ERR_PTR(ret) : alist;
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}
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/*
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* Get or create a fileserver record.
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*/
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struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key,
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const uuid_t *uuid, u32 addr_version)
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{
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struct afs_addr_list *alist;
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struct afs_server *server, *candidate;
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_enter("%p,%pU", cell->net, uuid);
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server = afs_find_server_by_uuid(cell->net, uuid);
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if (server) {
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if (server->addr_version != addr_version)
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set_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags);
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return server;
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}
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alist = afs_vl_lookup_addrs(cell, key, uuid);
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if (IS_ERR(alist))
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return ERR_CAST(alist);
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candidate = afs_alloc_server(cell, uuid, alist);
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if (!candidate) {
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afs_put_addrlist(alist);
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return ERR_PTR(-ENOMEM);
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}
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server = afs_install_server(cell, candidate);
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if (server != candidate) {
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afs_put_addrlist(alist);
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kfree(candidate);
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} else {
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/* Immediately dispatch an asynchronous probe to each interface
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* on the fileserver. This will make sure the repeat-probing
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* service is started.
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*/
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afs_fs_probe_fileserver(cell->net, server, key, true);
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}
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return server;
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}
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/*
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* Set the server timer to fire after a given delay, assuming it's not already
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* set for an earlier time.
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*/
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static void afs_set_server_timer(struct afs_net *net, time64_t delay)
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{
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if (net->live) {
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afs_inc_servers_outstanding(net);
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if (timer_reduce(&net->fs_timer, jiffies + delay * HZ))
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afs_dec_servers_outstanding(net);
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}
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}
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/*
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* Server management timer. We have an increment on fs_outstanding that we
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* need to pass along to the work item.
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*/
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void afs_servers_timer(struct timer_list *timer)
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{
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struct afs_net *net = container_of(timer, struct afs_net, fs_timer);
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_enter("");
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if (!queue_work(afs_wq, &net->fs_manager))
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afs_dec_servers_outstanding(net);
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}
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/*
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* Get a reference on a server object.
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*/
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struct afs_server *afs_get_server(struct afs_server *server,
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enum afs_server_trace reason)
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{
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unsigned int u = atomic_inc_return(&server->ref);
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trace_afs_server(server, u, atomic_read(&server->active), reason);
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return server;
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}
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/*
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* Try to get a reference on a server object.
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*/
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static struct afs_server *afs_maybe_use_server(struct afs_server *server,
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enum afs_server_trace reason)
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{
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unsigned int r = atomic_fetch_add_unless(&server->ref, 1, 0);
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unsigned int a;
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if (r == 0)
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return NULL;
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a = atomic_inc_return(&server->active);
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trace_afs_server(server, r, a, reason);
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return server;
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}
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/*
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* Get an active count on a server object.
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*/
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struct afs_server *afs_use_server(struct afs_server *server, enum afs_server_trace reason)
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{
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unsigned int r = atomic_inc_return(&server->ref);
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unsigned int a = atomic_inc_return(&server->active);
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trace_afs_server(server, r, a, reason);
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return server;
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}
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/*
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* Release a reference on a server record.
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*/
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void afs_put_server(struct afs_net *net, struct afs_server *server,
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enum afs_server_trace reason)
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{
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unsigned int usage;
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if (!server)
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return;
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usage = atomic_dec_return(&server->ref);
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trace_afs_server(server, usage, atomic_read(&server->active), reason);
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if (unlikely(usage == 0))
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__afs_put_server(net, server);
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}
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/*
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* Drop an active count on a server object without updating the last-unused
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* time.
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*/
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void afs_unuse_server_notime(struct afs_net *net, struct afs_server *server,
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enum afs_server_trace reason)
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{
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if (server) {
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unsigned int active = atomic_dec_return(&server->active);
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if (active == 0)
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afs_set_server_timer(net, afs_server_gc_delay);
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afs_put_server(net, server, reason);
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}
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}
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/*
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* Drop an active count on a server object.
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*/
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void afs_unuse_server(struct afs_net *net, struct afs_server *server,
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enum afs_server_trace reason)
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{
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if (server) {
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server->unuse_time = ktime_get_real_seconds();
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afs_unuse_server_notime(net, server, reason);
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}
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}
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static void afs_server_rcu(struct rcu_head *rcu)
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{
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struct afs_server *server = container_of(rcu, struct afs_server, rcu);
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trace_afs_server(server, atomic_read(&server->ref),
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atomic_read(&server->active), afs_server_trace_free);
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afs_put_addrlist(rcu_access_pointer(server->addresses));
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kfree(server);
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}
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static void __afs_put_server(struct afs_net *net, struct afs_server *server)
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{
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call_rcu(&server->rcu, afs_server_rcu);
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afs_dec_servers_outstanding(net);
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}
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static void afs_give_up_callbacks(struct afs_net *net, struct afs_server *server)
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{
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struct afs_addr_list *alist = rcu_access_pointer(server->addresses);
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struct afs_addr_cursor ac = {
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.alist = alist,
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.index = alist->preferred,
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.error = 0,
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};
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afs_fs_give_up_all_callbacks(net, server, &ac, NULL);
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}
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/*
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* destroy a dead server
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*/
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static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
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{
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if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags))
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afs_give_up_callbacks(net, server);
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afs_put_server(net, server, afs_server_trace_destroy);
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}
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/*
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* Garbage collect any expired servers.
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*/
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static void afs_gc_servers(struct afs_net *net, struct afs_server *gc_list)
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{
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struct afs_server *server, *next, *prev;
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int active;
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while ((server = gc_list)) {
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gc_list = server->gc_next;
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write_seqlock(&net->fs_lock);
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active = atomic_read(&server->active);
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if (active == 0) {
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trace_afs_server(server, atomic_read(&server->ref),
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active, afs_server_trace_gc);
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next = rcu_dereference_protected(
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server->uuid_next, lockdep_is_held(&net->fs_lock.lock));
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prev = server->uuid_prev;
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if (!prev) {
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/* The one at the front is in the tree */
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if (!next) {
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rb_erase(&server->uuid_rb, &net->fs_servers);
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} else {
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rb_replace_node_rcu(&server->uuid_rb,
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&next->uuid_rb,
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&net->fs_servers);
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next->uuid_prev = NULL;
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}
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} else {
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/* This server is not at the front */
|
|
rcu_assign_pointer(prev->uuid_next, next);
|
|
if (next)
|
|
next->uuid_prev = prev;
|
|
}
|
|
|
|
list_del(&server->probe_link);
|
|
hlist_del_rcu(&server->proc_link);
|
|
if (!hlist_unhashed(&server->addr4_link))
|
|
hlist_del_rcu(&server->addr4_link);
|
|
if (!hlist_unhashed(&server->addr6_link))
|
|
hlist_del_rcu(&server->addr6_link);
|
|
}
|
|
write_sequnlock(&net->fs_lock);
|
|
|
|
if (active == 0)
|
|
afs_destroy_server(net, server);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Manage the records of servers known to be within a network namespace. This
|
|
* includes garbage collecting unused servers.
|
|
*
|
|
* Note also that we were given an increment on net->servers_outstanding by
|
|
* whoever queued us that we need to deal with before returning.
|
|
*/
|
|
void afs_manage_servers(struct work_struct *work)
|
|
{
|
|
struct afs_net *net = container_of(work, struct afs_net, fs_manager);
|
|
struct afs_server *gc_list = NULL;
|
|
struct rb_node *cursor;
|
|
time64_t now = ktime_get_real_seconds(), next_manage = TIME64_MAX;
|
|
bool purging = !net->live;
|
|
|
|
_enter("");
|
|
|
|
/* Trawl the server list looking for servers that have expired from
|
|
* lack of use.
|
|
*/
|
|
read_seqlock_excl(&net->fs_lock);
|
|
|
|
for (cursor = rb_first(&net->fs_servers); cursor; cursor = rb_next(cursor)) {
|
|
struct afs_server *server =
|
|
rb_entry(cursor, struct afs_server, uuid_rb);
|
|
int active = atomic_read(&server->active);
|
|
|
|
_debug("manage %pU %u", &server->uuid, active);
|
|
|
|
if (purging) {
|
|
trace_afs_server(server, atomic_read(&server->ref),
|
|
active, afs_server_trace_purging);
|
|
if (active != 0)
|
|
pr_notice("Can't purge s=%08x\n", server->debug_id);
|
|
}
|
|
|
|
if (active == 0) {
|
|
time64_t expire_at = server->unuse_time;
|
|
|
|
if (!test_bit(AFS_SERVER_FL_VL_FAIL, &server->flags) &&
|
|
!test_bit(AFS_SERVER_FL_NOT_FOUND, &server->flags))
|
|
expire_at += afs_server_gc_delay;
|
|
if (purging || expire_at <= now) {
|
|
server->gc_next = gc_list;
|
|
gc_list = server;
|
|
} else if (expire_at < next_manage) {
|
|
next_manage = expire_at;
|
|
}
|
|
}
|
|
}
|
|
|
|
read_sequnlock_excl(&net->fs_lock);
|
|
|
|
/* Update the timer on the way out. We have to pass an increment on
|
|
* servers_outstanding in the namespace that we are in to the timer or
|
|
* the work scheduler.
|
|
*/
|
|
if (!purging && next_manage < TIME64_MAX) {
|
|
now = ktime_get_real_seconds();
|
|
|
|
if (next_manage - now <= 0) {
|
|
if (queue_work(afs_wq, &net->fs_manager))
|
|
afs_inc_servers_outstanding(net);
|
|
} else {
|
|
afs_set_server_timer(net, next_manage - now);
|
|
}
|
|
}
|
|
|
|
afs_gc_servers(net, gc_list);
|
|
|
|
afs_dec_servers_outstanding(net);
|
|
_leave(" [%d]", atomic_read(&net->servers_outstanding));
|
|
}
|
|
|
|
static void afs_queue_server_manager(struct afs_net *net)
|
|
{
|
|
afs_inc_servers_outstanding(net);
|
|
if (!queue_work(afs_wq, &net->fs_manager))
|
|
afs_dec_servers_outstanding(net);
|
|
}
|
|
|
|
/*
|
|
* Purge list of servers.
|
|
*/
|
|
void afs_purge_servers(struct afs_net *net)
|
|
{
|
|
_enter("");
|
|
|
|
if (del_timer_sync(&net->fs_timer))
|
|
afs_dec_servers_outstanding(net);
|
|
|
|
afs_queue_server_manager(net);
|
|
|
|
_debug("wait");
|
|
atomic_dec(&net->servers_outstanding);
|
|
wait_var_event(&net->servers_outstanding,
|
|
!atomic_read(&net->servers_outstanding));
|
|
_leave("");
|
|
}
|
|
|
|
/*
|
|
* Get an update for a server's address list.
|
|
*/
|
|
static noinline bool afs_update_server_record(struct afs_operation *op,
|
|
struct afs_server *server)
|
|
{
|
|
struct afs_addr_list *alist, *discard;
|
|
|
|
_enter("");
|
|
|
|
trace_afs_server(server, atomic_read(&server->ref), atomic_read(&server->active),
|
|
afs_server_trace_update);
|
|
|
|
alist = afs_vl_lookup_addrs(op->volume->cell, op->key, &server->uuid);
|
|
if (IS_ERR(alist)) {
|
|
if ((PTR_ERR(alist) == -ERESTARTSYS ||
|
|
PTR_ERR(alist) == -EINTR) &&
|
|
(op->flags & AFS_OPERATION_UNINTR) &&
|
|
server->addresses) {
|
|
_leave(" = t [intr]");
|
|
return true;
|
|
}
|
|
op->error = PTR_ERR(alist);
|
|
_leave(" = f [%d]", op->error);
|
|
return false;
|
|
}
|
|
|
|
discard = alist;
|
|
if (server->addr_version != alist->version) {
|
|
write_lock(&server->fs_lock);
|
|
discard = rcu_dereference_protected(server->addresses,
|
|
lockdep_is_held(&server->fs_lock));
|
|
rcu_assign_pointer(server->addresses, alist);
|
|
server->addr_version = alist->version;
|
|
write_unlock(&server->fs_lock);
|
|
}
|
|
|
|
afs_put_addrlist(discard);
|
|
_leave(" = t");
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* See if a server's address list needs updating.
|
|
*/
|
|
bool afs_check_server_record(struct afs_operation *op, struct afs_server *server)
|
|
{
|
|
bool success;
|
|
int ret, retries = 0;
|
|
|
|
_enter("");
|
|
|
|
ASSERT(server);
|
|
|
|
retry:
|
|
if (test_bit(AFS_SERVER_FL_UPDATING, &server->flags))
|
|
goto wait;
|
|
if (test_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags))
|
|
goto update;
|
|
_leave(" = t [good]");
|
|
return true;
|
|
|
|
update:
|
|
if (!test_and_set_bit_lock(AFS_SERVER_FL_UPDATING, &server->flags)) {
|
|
clear_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags);
|
|
success = afs_update_server_record(op, server);
|
|
clear_bit_unlock(AFS_SERVER_FL_UPDATING, &server->flags);
|
|
wake_up_bit(&server->flags, AFS_SERVER_FL_UPDATING);
|
|
_leave(" = %d", success);
|
|
return success;
|
|
}
|
|
|
|
wait:
|
|
ret = wait_on_bit(&server->flags, AFS_SERVER_FL_UPDATING,
|
|
(op->flags & AFS_OPERATION_UNINTR) ?
|
|
TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE);
|
|
if (ret == -ERESTARTSYS) {
|
|
op->error = ret;
|
|
_leave(" = f [intr]");
|
|
return false;
|
|
}
|
|
|
|
retries++;
|
|
if (retries == 4) {
|
|
_leave(" = f [stale]");
|
|
ret = -ESTALE;
|
|
return false;
|
|
}
|
|
goto retry;
|
|
}
|