1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* AFS server record management
4 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #include <linux/sched.h>
9 #include <linux/slab.h>
12 #include "protocol_yfs.h"
14 static unsigned afs_server_gc_delay = 10; /* Server record timeout in seconds */
15 static unsigned afs_server_update_delay = 30; /* Time till VLDB recheck in secs */
16 static atomic_t afs_server_debug_id;
18 static void afs_inc_servers_outstanding(struct afs_net *net)
20 atomic_inc(&net->servers_outstanding);
23 static void afs_dec_servers_outstanding(struct afs_net *net)
25 if (atomic_dec_and_test(&net->servers_outstanding))
26 wake_up_var(&net->servers_outstanding);
30 * Find a server by one of its addresses.
32 struct afs_server *afs_find_server(struct afs_net *net,
33 const struct sockaddr_rxrpc *srx)
35 const struct afs_addr_list *alist;
36 struct afs_server *server = NULL;
44 afs_put_server(net, server, afs_server_trace_put_find_rsq);
46 read_seqbegin_or_lock(&net->fs_addr_lock, &seq);
48 if (srx->transport.family == AF_INET6) {
49 const struct sockaddr_in6 *a = &srx->transport.sin6, *b;
50 hlist_for_each_entry_rcu(server, &net->fs_addresses6, addr6_link) {
51 alist = rcu_dereference(server->addresses);
52 for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
53 b = &alist->addrs[i].transport.sin6;
54 diff = ((u16 __force)a->sin6_port -
55 (u16 __force)b->sin6_port);
57 diff = memcmp(&a->sin6_addr,
59 sizeof(struct in6_addr));
65 const struct sockaddr_in *a = &srx->transport.sin, *b;
66 hlist_for_each_entry_rcu(server, &net->fs_addresses4, addr4_link) {
67 alist = rcu_dereference(server->addresses);
68 for (i = 0; i < alist->nr_ipv4; i++) {
69 b = &alist->addrs[i].transport.sin;
70 diff = ((u16 __force)a->sin_port -
71 (u16 __force)b->sin_port);
73 diff = ((u32 __force)a->sin_addr.s_addr -
74 (u32 __force)b->sin_addr.s_addr);
83 if (server && !atomic_inc_not_zero(&server->usage))
86 } while (need_seqretry(&net->fs_addr_lock, seq));
88 done_seqretry(&net->fs_addr_lock, seq);
95 * Look up a server by its UUID
97 struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uuid)
99 struct afs_server *server = NULL;
106 /* Unfortunately, rbtree walking doesn't give reliable results
107 * under just the RCU read lock, so we have to check for
111 afs_put_server(net, server, afs_server_trace_put_uuid_rsq);
114 read_seqbegin_or_lock(&net->fs_lock, &seq);
116 p = net->fs_servers.rb_node;
118 server = rb_entry(p, struct afs_server, uuid_rb);
120 diff = memcmp(uuid, &server->uuid, sizeof(*uuid));
123 } else if (diff > 0) {
126 afs_get_server(server, afs_server_trace_get_by_uuid);
132 } while (need_seqretry(&net->fs_lock, seq));
134 done_seqretry(&net->fs_lock, seq);
136 _leave(" = %p", server);
141 * Install a server record in the namespace tree
143 static struct afs_server *afs_install_server(struct afs_net *net,
144 struct afs_server *candidate)
146 const struct afs_addr_list *alist;
147 struct afs_server *server;
148 struct rb_node **pp, *p;
149 int ret = -EEXIST, diff;
151 _enter("%p", candidate);
153 write_seqlock(&net->fs_lock);
155 /* Firstly install the server in the UUID lookup tree */
156 pp = &net->fs_servers.rb_node;
160 _debug("- consider %p", p);
161 server = rb_entry(p, struct afs_server, uuid_rb);
162 diff = memcmp(&candidate->uuid, &server->uuid, sizeof(uuid_t));
164 pp = &(*pp)->rb_left;
166 pp = &(*pp)->rb_right;
172 rb_link_node(&server->uuid_rb, p, pp);
173 rb_insert_color(&server->uuid_rb, &net->fs_servers);
174 hlist_add_head_rcu(&server->proc_link, &net->fs_proc);
176 write_seqlock(&net->fs_addr_lock);
177 alist = rcu_dereference_protected(server->addresses,
178 lockdep_is_held(&net->fs_addr_lock.lock));
180 /* Secondly, if the server has any IPv4 and/or IPv6 addresses, install
181 * it in the IPv4 and/or IPv6 reverse-map lists.
183 * TODO: For speed we want to use something other than a flat list
184 * here; even sorting the list in terms of lowest address would help a
185 * bit, but anything we might want to do gets messy and memory
188 if (alist->nr_ipv4 > 0)
189 hlist_add_head_rcu(&server->addr4_link, &net->fs_addresses4);
190 if (alist->nr_addrs > alist->nr_ipv4)
191 hlist_add_head_rcu(&server->addr6_link, &net->fs_addresses6);
193 write_sequnlock(&net->fs_addr_lock);
197 afs_get_server(server, afs_server_trace_get_install);
198 write_sequnlock(&net->fs_lock);
203 * allocate a new server record
205 static struct afs_server *afs_alloc_server(struct afs_net *net,
207 struct afs_addr_list *alist)
209 struct afs_server *server;
213 server = kzalloc(sizeof(struct afs_server), GFP_KERNEL);
217 atomic_set(&server->usage, 1);
218 server->debug_id = atomic_inc_return(&afs_server_debug_id);
219 RCU_INIT_POINTER(server->addresses, alist);
220 server->addr_version = alist->version;
221 server->uuid = *uuid;
222 server->update_at = ktime_get_real_seconds() + afs_server_update_delay;
223 rwlock_init(&server->fs_lock);
224 INIT_HLIST_HEAD(&server->cb_volumes);
225 rwlock_init(&server->cb_break_lock);
226 init_waitqueue_head(&server->probe_wq);
227 spin_lock_init(&server->probe_lock);
229 afs_inc_servers_outstanding(net);
230 trace_afs_server(server, 1, afs_server_trace_alloc);
231 _leave(" = %p", server);
235 _leave(" = NULL [nomem]");
240 * Look up an address record for a server
242 static struct afs_addr_list *afs_vl_lookup_addrs(struct afs_cell *cell,
243 struct key *key, const uuid_t *uuid)
245 struct afs_vl_cursor vc;
246 struct afs_addr_list *alist = NULL;
250 if (afs_begin_vlserver_operation(&vc, cell, key)) {
251 while (afs_select_vlserver(&vc)) {
252 if (test_bit(AFS_VLSERVER_FL_IS_YFS, &vc.server->flags))
253 alist = afs_yfsvl_get_endpoints(&vc, uuid);
255 alist = afs_vl_get_addrs_u(&vc, uuid);
258 ret = afs_end_vlserver_operation(&vc);
261 return ret < 0 ? ERR_PTR(ret) : alist;
265 * Get or create a fileserver record.
267 struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key,
270 struct afs_addr_list *alist;
271 struct afs_server *server, *candidate;
273 _enter("%p,%pU", cell->net, uuid);
275 server = afs_find_server_by_uuid(cell->net, uuid);
279 alist = afs_vl_lookup_addrs(cell, key, uuid);
281 return ERR_CAST(alist);
283 candidate = afs_alloc_server(cell->net, uuid, alist);
285 afs_put_addrlist(alist);
286 return ERR_PTR(-ENOMEM);
289 server = afs_install_server(cell->net, candidate);
290 if (server != candidate) {
291 afs_put_addrlist(alist);
295 _leave(" = %p{%d}", server, atomic_read(&server->usage));
300 * Set the server timer to fire after a given delay, assuming it's not already
301 * set for an earlier time.
303 static void afs_set_server_timer(struct afs_net *net, time64_t delay)
306 afs_inc_servers_outstanding(net);
307 if (timer_reduce(&net->fs_timer, jiffies + delay * HZ))
308 afs_dec_servers_outstanding(net);
313 * Server management timer. We have an increment on fs_outstanding that we
314 * need to pass along to the work item.
316 void afs_servers_timer(struct timer_list *timer)
318 struct afs_net *net = container_of(timer, struct afs_net, fs_timer);
321 if (!queue_work(afs_wq, &net->fs_manager))
322 afs_dec_servers_outstanding(net);
326 * Get a reference on a server object.
328 struct afs_server *afs_get_server(struct afs_server *server,
329 enum afs_server_trace reason)
331 unsigned int u = atomic_inc_return(&server->usage);
333 trace_afs_server(server, u, reason);
338 * Release a reference on a server record.
340 void afs_put_server(struct afs_net *net, struct afs_server *server,
341 enum afs_server_trace reason)
348 server->put_time = ktime_get_real_seconds();
350 usage = atomic_dec_return(&server->usage);
352 trace_afs_server(server, usage, reason);
354 if (likely(usage > 0))
357 afs_set_server_timer(net, afs_server_gc_delay);
360 static void afs_server_rcu(struct rcu_head *rcu)
362 struct afs_server *server = container_of(rcu, struct afs_server, rcu);
364 trace_afs_server(server, atomic_read(&server->usage),
365 afs_server_trace_free);
366 afs_put_addrlist(rcu_access_pointer(server->addresses));
371 * destroy a dead server
373 static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
375 struct afs_addr_list *alist = rcu_access_pointer(server->addresses);
376 struct afs_addr_cursor ac = {
378 .index = alist->preferred,
382 trace_afs_server(server, atomic_read(&server->usage),
383 afs_server_trace_give_up_cb);
385 if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags))
386 afs_fs_give_up_all_callbacks(net, server, &ac, NULL);
388 wait_var_event(&server->probe_outstanding,
389 atomic_read(&server->probe_outstanding) == 0);
391 trace_afs_server(server, atomic_read(&server->usage),
392 afs_server_trace_destroy);
393 call_rcu(&server->rcu, afs_server_rcu);
394 afs_dec_servers_outstanding(net);
398 * Garbage collect any expired servers.
400 static void afs_gc_servers(struct afs_net *net, struct afs_server *gc_list)
402 struct afs_server *server;
406 while ((server = gc_list)) {
407 gc_list = server->gc_next;
409 write_seqlock(&net->fs_lock);
411 deleted = atomic_try_cmpxchg(&server->usage, &usage, 0);
412 trace_afs_server(server, usage, afs_server_trace_gc);
414 rb_erase(&server->uuid_rb, &net->fs_servers);
415 hlist_del_rcu(&server->proc_link);
417 write_sequnlock(&net->fs_lock);
420 write_seqlock(&net->fs_addr_lock);
421 if (!hlist_unhashed(&server->addr4_link))
422 hlist_del_rcu(&server->addr4_link);
423 if (!hlist_unhashed(&server->addr6_link))
424 hlist_del_rcu(&server->addr6_link);
425 write_sequnlock(&net->fs_addr_lock);
426 afs_destroy_server(net, server);
432 * Manage the records of servers known to be within a network namespace. This
433 * includes garbage collecting unused servers.
435 * Note also that we were given an increment on net->servers_outstanding by
436 * whoever queued us that we need to deal with before returning.
438 void afs_manage_servers(struct work_struct *work)
440 struct afs_net *net = container_of(work, struct afs_net, fs_manager);
441 struct afs_server *gc_list = NULL;
442 struct rb_node *cursor;
443 time64_t now = ktime_get_real_seconds(), next_manage = TIME64_MAX;
444 bool purging = !net->live;
448 /* Trawl the server list looking for servers that have expired from
451 read_seqlock_excl(&net->fs_lock);
453 for (cursor = rb_first(&net->fs_servers); cursor; cursor = rb_next(cursor)) {
454 struct afs_server *server =
455 rb_entry(cursor, struct afs_server, uuid_rb);
456 int usage = atomic_read(&server->usage);
458 _debug("manage %pU %u", &server->uuid, usage);
460 ASSERTCMP(usage, >=, 1);
461 ASSERTIFCMP(purging, usage, ==, 1);
464 time64_t expire_at = server->put_time;
466 if (!test_bit(AFS_SERVER_FL_VL_FAIL, &server->flags) &&
467 !test_bit(AFS_SERVER_FL_NOT_FOUND, &server->flags))
468 expire_at += afs_server_gc_delay;
469 if (purging || expire_at <= now) {
470 server->gc_next = gc_list;
472 } else if (expire_at < next_manage) {
473 next_manage = expire_at;
478 read_sequnlock_excl(&net->fs_lock);
480 /* Update the timer on the way out. We have to pass an increment on
481 * servers_outstanding in the namespace that we are in to the timer or
482 * the work scheduler.
484 if (!purging && next_manage < TIME64_MAX) {
485 now = ktime_get_real_seconds();
487 if (next_manage - now <= 0) {
488 if (queue_work(afs_wq, &net->fs_manager))
489 afs_inc_servers_outstanding(net);
491 afs_set_server_timer(net, next_manage - now);
495 afs_gc_servers(net, gc_list);
497 afs_dec_servers_outstanding(net);
498 _leave(" [%d]", atomic_read(&net->servers_outstanding));
501 static void afs_queue_server_manager(struct afs_net *net)
503 afs_inc_servers_outstanding(net);
504 if (!queue_work(afs_wq, &net->fs_manager))
505 afs_dec_servers_outstanding(net);
509 * Purge list of servers.
511 void afs_purge_servers(struct afs_net *net)
515 if (del_timer_sync(&net->fs_timer))
516 atomic_dec(&net->servers_outstanding);
518 afs_queue_server_manager(net);
521 wait_var_event(&net->servers_outstanding,
522 !atomic_read(&net->servers_outstanding));
527 * Get an update for a server's address list.
529 static noinline bool afs_update_server_record(struct afs_fs_cursor *fc, struct afs_server *server)
531 struct afs_addr_list *alist, *discard;
535 trace_afs_server(server, atomic_read(&server->usage), afs_server_trace_update);
537 alist = afs_vl_lookup_addrs(fc->vnode->volume->cell, fc->key,
540 if ((PTR_ERR(alist) == -ERESTARTSYS ||
541 PTR_ERR(alist) == -EINTR) &&
542 !(fc->flags & AFS_FS_CURSOR_INTR) &&
544 _leave(" = t [intr]");
547 fc->error = PTR_ERR(alist);
548 _leave(" = f [%d]", fc->error);
553 if (server->addr_version != alist->version) {
554 write_lock(&server->fs_lock);
555 discard = rcu_dereference_protected(server->addresses,
556 lockdep_is_held(&server->fs_lock));
557 rcu_assign_pointer(server->addresses, alist);
558 server->addr_version = alist->version;
559 write_unlock(&server->fs_lock);
562 server->update_at = ktime_get_real_seconds() + afs_server_update_delay;
563 afs_put_addrlist(discard);
569 * See if a server's address list needs updating.
571 bool afs_check_server_record(struct afs_fs_cursor *fc, struct afs_server *server)
573 time64_t now = ktime_get_real_seconds();
576 int ret, retries = 0;
583 diff = READ_ONCE(server->update_at) - now;
585 _leave(" = t [not now %ld]", diff);
589 if (!test_and_set_bit_lock(AFS_SERVER_FL_UPDATING, &server->flags)) {
590 success = afs_update_server_record(fc, server);
591 clear_bit_unlock(AFS_SERVER_FL_UPDATING, &server->flags);
592 wake_up_bit(&server->flags, AFS_SERVER_FL_UPDATING);
593 _leave(" = %d", success);
597 ret = wait_on_bit(&server->flags, AFS_SERVER_FL_UPDATING,
598 (fc->flags & AFS_FS_CURSOR_INTR) ?
599 TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
600 if (ret == -ERESTARTSYS) {
602 _leave(" = f [intr]");
608 _leave(" = f [stale]");