1 /* AFS server record management
3 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/sched.h>
13 #include <linux/slab.h>
16 #include "protocol_yfs.h"
18 static unsigned afs_server_gc_delay
= 10; /* Server record timeout in seconds */
19 static unsigned afs_server_update_delay
= 30; /* Time till VLDB recheck in secs */
21 static void afs_inc_servers_outstanding(struct afs_net
*net
)
23 atomic_inc(&net
->servers_outstanding
);
26 static void afs_dec_servers_outstanding(struct afs_net
*net
)
28 if (atomic_dec_and_test(&net
->servers_outstanding
))
29 wake_up_var(&net
->servers_outstanding
);
33 * Find a server by one of its addresses.
35 struct afs_server
*afs_find_server(struct afs_net
*net
,
36 const struct sockaddr_rxrpc
*srx
)
38 const struct sockaddr_in6
*a
= &srx
->transport
.sin6
, *b
;
39 const struct afs_addr_list
*alist
;
40 struct afs_server
*server
= NULL
;
45 if (srx
->transport
.sin6
.sin6_addr
.s6_addr32
[0] == 0 ||
46 srx
->transport
.sin6
.sin6_addr
.s6_addr32
[1] == 0 ||
47 srx
->transport
.sin6
.sin6_addr
.s6_addr32
[2] == htonl(0xffff))
54 afs_put_server(net
, server
);
56 read_seqbegin_or_lock(&net
->fs_addr_lock
, &seq
);
59 hlist_for_each_entry_rcu(server
, &net
->fs_addresses6
, addr6_link
) {
60 alist
= rcu_dereference(server
->addresses
);
61 for (i
= alist
->nr_ipv4
; i
< alist
->nr_addrs
; i
++) {
62 b
= &alist
->addrs
[i
].transport
.sin6
;
63 diff
= ((u16 __force
)a
->sin6_port
-
64 (u16 __force
)b
->sin6_port
);
66 diff
= memcmp(&a
->sin6_addr
,
68 sizeof(struct in6_addr
));
74 hlist_for_each_entry_rcu(server
, &net
->fs_addresses4
, addr4_link
) {
75 alist
= rcu_dereference(server
->addresses
);
76 for (i
= 0; i
< alist
->nr_ipv4
; i
++) {
77 b
= &alist
->addrs
[i
].transport
.sin6
;
78 diff
= ((u16 __force
)a
->sin6_port
-
79 (u16 __force
)b
->sin6_port
);
81 diff
= ((u32 __force
)a
->sin6_addr
.s6_addr32
[3] -
82 (u32 __force
)b
->sin6_addr
.s6_addr32
[3]);
91 if (server
&& !atomic_inc_not_zero(&server
->usage
))
94 } while (need_seqretry(&net
->fs_addr_lock
, seq
));
96 done_seqretry(&net
->fs_addr_lock
, seq
);
103 * Look up a server by its UUID
105 struct afs_server
*afs_find_server_by_uuid(struct afs_net
*net
, const uuid_t
*uuid
)
107 struct afs_server
*server
= NULL
;
114 /* Unfortunately, rbtree walking doesn't give reliable results
115 * under just the RCU read lock, so we have to check for
119 afs_put_server(net
, server
);
122 read_seqbegin_or_lock(&net
->fs_lock
, &seq
);
124 p
= net
->fs_servers
.rb_node
;
126 server
= rb_entry(p
, struct afs_server
, uuid_rb
);
128 diff
= memcmp(uuid
, &server
->uuid
, sizeof(*uuid
));
131 } else if (diff
> 0) {
134 afs_get_server(server
);
140 } while (need_seqretry(&net
->fs_lock
, seq
));
142 done_seqretry(&net
->fs_lock
, seq
);
144 _leave(" = %p", server
);
149 * Install a server record in the namespace tree
151 static struct afs_server
*afs_install_server(struct afs_net
*net
,
152 struct afs_server
*candidate
)
154 const struct afs_addr_list
*alist
;
155 struct afs_server
*server
;
156 struct rb_node
**pp
, *p
;
157 int ret
= -EEXIST
, diff
;
159 _enter("%p", candidate
);
161 write_seqlock(&net
->fs_lock
);
163 /* Firstly install the server in the UUID lookup tree */
164 pp
= &net
->fs_servers
.rb_node
;
168 _debug("- consider %p", p
);
169 server
= rb_entry(p
, struct afs_server
, uuid_rb
);
170 diff
= memcmp(&candidate
->uuid
, &server
->uuid
, sizeof(uuid_t
));
172 pp
= &(*pp
)->rb_left
;
174 pp
= &(*pp
)->rb_right
;
180 rb_link_node(&server
->uuid_rb
, p
, pp
);
181 rb_insert_color(&server
->uuid_rb
, &net
->fs_servers
);
182 hlist_add_head_rcu(&server
->proc_link
, &net
->fs_proc
);
184 write_seqlock(&net
->fs_addr_lock
);
185 alist
= rcu_dereference_protected(server
->addresses
,
186 lockdep_is_held(&net
->fs_addr_lock
.lock
));
188 /* Secondly, if the server has any IPv4 and/or IPv6 addresses, install
189 * it in the IPv4 and/or IPv6 reverse-map lists.
191 * TODO: For speed we want to use something other than a flat list
192 * here; even sorting the list in terms of lowest address would help a
193 * bit, but anything we might want to do gets messy and memory
196 if (alist
->nr_ipv4
> 0)
197 hlist_add_head_rcu(&server
->addr4_link
, &net
->fs_addresses4
);
198 if (alist
->nr_addrs
> alist
->nr_ipv4
)
199 hlist_add_head_rcu(&server
->addr6_link
, &net
->fs_addresses6
);
201 write_sequnlock(&net
->fs_addr_lock
);
205 afs_get_server(server
);
206 write_sequnlock(&net
->fs_lock
);
211 * allocate a new server record
213 static struct afs_server
*afs_alloc_server(struct afs_net
*net
,
215 struct afs_addr_list
*alist
)
217 struct afs_server
*server
;
221 server
= kzalloc(sizeof(struct afs_server
), GFP_KERNEL
);
225 atomic_set(&server
->usage
, 1);
226 RCU_INIT_POINTER(server
->addresses
, alist
);
227 server
->addr_version
= alist
->version
;
228 server
->uuid
= *uuid
;
229 server
->flags
= (1UL << AFS_SERVER_FL_NEW
);
230 server
->update_at
= ktime_get_real_seconds() + afs_server_update_delay
;
231 rwlock_init(&server
->fs_lock
);
232 INIT_HLIST_HEAD(&server
->cb_volumes
);
233 rwlock_init(&server
->cb_break_lock
);
234 init_waitqueue_head(&server
->probe_wq
);
235 spin_lock_init(&server
->probe_lock
);
237 afs_inc_servers_outstanding(net
);
238 _leave(" = %p", server
);
242 _leave(" = NULL [nomem]");
247 * Look up an address record for a server
249 static struct afs_addr_list
*afs_vl_lookup_addrs(struct afs_cell
*cell
,
250 struct key
*key
, const uuid_t
*uuid
)
252 struct afs_vl_cursor vc
;
253 struct afs_addr_list
*alist
= NULL
;
257 if (afs_begin_vlserver_operation(&vc
, cell
, key
)) {
258 while (afs_select_vlserver(&vc
)) {
259 if (test_bit(AFS_VLSERVER_FL_IS_YFS
, &vc
.server
->flags
))
260 alist
= afs_yfsvl_get_endpoints(&vc
, uuid
);
262 alist
= afs_vl_get_addrs_u(&vc
, uuid
);
265 ret
= afs_end_vlserver_operation(&vc
);
268 return ret
< 0 ? ERR_PTR(ret
) : alist
;
272 * Get or create a fileserver record.
274 struct afs_server
*afs_lookup_server(struct afs_cell
*cell
, struct key
*key
,
277 struct afs_addr_list
*alist
;
278 struct afs_server
*server
, *candidate
;
280 _enter("%p,%pU", cell
->net
, uuid
);
282 server
= afs_find_server_by_uuid(cell
->net
, uuid
);
286 alist
= afs_vl_lookup_addrs(cell
, key
, uuid
);
288 return ERR_CAST(alist
);
290 candidate
= afs_alloc_server(cell
->net
, uuid
, alist
);
292 afs_put_addrlist(alist
);
293 return ERR_PTR(-ENOMEM
);
296 server
= afs_install_server(cell
->net
, candidate
);
297 if (server
!= candidate
) {
298 afs_put_addrlist(alist
);
302 _leave(" = %p{%d}", server
, atomic_read(&server
->usage
));
307 * Set the server timer to fire after a given delay, assuming it's not already
308 * set for an earlier time.
310 static void afs_set_server_timer(struct afs_net
*net
, time64_t delay
)
313 afs_inc_servers_outstanding(net
);
314 if (timer_reduce(&net
->fs_timer
, jiffies
+ delay
* HZ
))
315 afs_dec_servers_outstanding(net
);
320 * Server management timer. We have an increment on fs_outstanding that we
321 * need to pass along to the work item.
323 void afs_servers_timer(struct timer_list
*timer
)
325 struct afs_net
*net
= container_of(timer
, struct afs_net
, fs_timer
);
328 if (!queue_work(afs_wq
, &net
->fs_manager
))
329 afs_dec_servers_outstanding(net
);
333 * Release a reference on a server record.
335 void afs_put_server(struct afs_net
*net
, struct afs_server
*server
)
342 server
->put_time
= ktime_get_real_seconds();
344 usage
= atomic_dec_return(&server
->usage
);
346 _enter("{%u}", usage
);
348 if (likely(usage
> 0))
351 afs_set_server_timer(net
, afs_server_gc_delay
);
354 static void afs_server_rcu(struct rcu_head
*rcu
)
356 struct afs_server
*server
= container_of(rcu
, struct afs_server
, rcu
);
358 afs_put_addrlist(rcu_access_pointer(server
->addresses
));
363 * destroy a dead server
365 static void afs_destroy_server(struct afs_net
*net
, struct afs_server
*server
)
367 struct afs_addr_list
*alist
= rcu_access_pointer(server
->addresses
);
368 struct afs_addr_cursor ac
= {
370 .index
= alist
->preferred
,
373 _enter("%p", server
);
375 if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB
, &server
->flags
))
376 afs_fs_give_up_all_callbacks(net
, server
, &ac
, NULL
);
378 wait_var_event(&server
->probe_outstanding
,
379 atomic_read(&server
->probe_outstanding
) == 0);
381 call_rcu(&server
->rcu
, afs_server_rcu
);
382 afs_dec_servers_outstanding(net
);
386 * Garbage collect any expired servers.
388 static void afs_gc_servers(struct afs_net
*net
, struct afs_server
*gc_list
)
390 struct afs_server
*server
;
394 while ((server
= gc_list
)) {
395 gc_list
= server
->gc_next
;
397 write_seqlock(&net
->fs_lock
);
399 deleted
= atomic_try_cmpxchg(&server
->usage
, &usage
, 0);
401 rb_erase(&server
->uuid_rb
, &net
->fs_servers
);
402 hlist_del_rcu(&server
->proc_link
);
404 write_sequnlock(&net
->fs_lock
);
407 write_seqlock(&net
->fs_addr_lock
);
408 if (!hlist_unhashed(&server
->addr4_link
))
409 hlist_del_rcu(&server
->addr4_link
);
410 if (!hlist_unhashed(&server
->addr6_link
))
411 hlist_del_rcu(&server
->addr6_link
);
412 write_sequnlock(&net
->fs_addr_lock
);
413 afs_destroy_server(net
, server
);
419 * Manage the records of servers known to be within a network namespace. This
420 * includes garbage collecting unused servers.
422 * Note also that we were given an increment on net->servers_outstanding by
423 * whoever queued us that we need to deal with before returning.
425 void afs_manage_servers(struct work_struct
*work
)
427 struct afs_net
*net
= container_of(work
, struct afs_net
, fs_manager
);
428 struct afs_server
*gc_list
= NULL
;
429 struct rb_node
*cursor
;
430 time64_t now
= ktime_get_real_seconds(), next_manage
= TIME64_MAX
;
431 bool purging
= !net
->live
;
435 /* Trawl the server list looking for servers that have expired from
438 read_seqlock_excl(&net
->fs_lock
);
440 for (cursor
= rb_first(&net
->fs_servers
); cursor
; cursor
= rb_next(cursor
)) {
441 struct afs_server
*server
=
442 rb_entry(cursor
, struct afs_server
, uuid_rb
);
443 int usage
= atomic_read(&server
->usage
);
445 _debug("manage %pU %u", &server
->uuid
, usage
);
447 ASSERTCMP(usage
, >=, 1);
448 ASSERTIFCMP(purging
, usage
, ==, 1);
451 time64_t expire_at
= server
->put_time
;
453 if (!test_bit(AFS_SERVER_FL_VL_FAIL
, &server
->flags
) &&
454 !test_bit(AFS_SERVER_FL_NOT_FOUND
, &server
->flags
))
455 expire_at
+= afs_server_gc_delay
;
456 if (purging
|| expire_at
<= now
) {
457 server
->gc_next
= gc_list
;
459 } else if (expire_at
< next_manage
) {
460 next_manage
= expire_at
;
465 read_sequnlock_excl(&net
->fs_lock
);
467 /* Update the timer on the way out. We have to pass an increment on
468 * servers_outstanding in the namespace that we are in to the timer or
469 * the work scheduler.
471 if (!purging
&& next_manage
< TIME64_MAX
) {
472 now
= ktime_get_real_seconds();
474 if (next_manage
- now
<= 0) {
475 if (queue_work(afs_wq
, &net
->fs_manager
))
476 afs_inc_servers_outstanding(net
);
478 afs_set_server_timer(net
, next_manage
- now
);
482 afs_gc_servers(net
, gc_list
);
484 afs_dec_servers_outstanding(net
);
485 _leave(" [%d]", atomic_read(&net
->servers_outstanding
));
488 static void afs_queue_server_manager(struct afs_net
*net
)
490 afs_inc_servers_outstanding(net
);
491 if (!queue_work(afs_wq
, &net
->fs_manager
))
492 afs_dec_servers_outstanding(net
);
496 * Purge list of servers.
498 void afs_purge_servers(struct afs_net
*net
)
502 if (del_timer_sync(&net
->fs_timer
))
503 atomic_dec(&net
->servers_outstanding
);
505 afs_queue_server_manager(net
);
508 wait_var_event(&net
->servers_outstanding
,
509 !atomic_read(&net
->servers_outstanding
));
514 * Get an update for a server's address list.
516 static noinline
bool afs_update_server_record(struct afs_fs_cursor
*fc
, struct afs_server
*server
)
518 struct afs_addr_list
*alist
, *discard
;
522 alist
= afs_vl_lookup_addrs(fc
->vnode
->volume
->cell
, fc
->key
,
525 fc
->ac
.error
= PTR_ERR(alist
);
526 _leave(" = f [%d]", fc
->ac
.error
);
531 if (server
->addr_version
!= alist
->version
) {
532 write_lock(&server
->fs_lock
);
533 discard
= rcu_dereference_protected(server
->addresses
,
534 lockdep_is_held(&server
->fs_lock
));
535 rcu_assign_pointer(server
->addresses
, alist
);
536 server
->addr_version
= alist
->version
;
537 write_unlock(&server
->fs_lock
);
540 server
->update_at
= ktime_get_real_seconds() + afs_server_update_delay
;
541 afs_put_addrlist(discard
);
547 * See if a server's address list needs updating.
549 bool afs_check_server_record(struct afs_fs_cursor
*fc
, struct afs_server
*server
)
551 time64_t now
= ktime_get_real_seconds();
554 int ret
, retries
= 0;
561 diff
= READ_ONCE(server
->update_at
) - now
;
563 _leave(" = t [not now %ld]", diff
);
567 if (!test_and_set_bit_lock(AFS_SERVER_FL_UPDATING
, &server
->flags
)) {
568 success
= afs_update_server_record(fc
, server
);
569 clear_bit_unlock(AFS_SERVER_FL_UPDATING
, &server
->flags
);
570 wake_up_bit(&server
->flags
, AFS_SERVER_FL_UPDATING
);
571 _leave(" = %d", success
);
575 ret
= wait_on_bit(&server
->flags
, AFS_SERVER_FL_UPDATING
,
577 if (ret
== -ERESTARTSYS
) {
579 _leave(" = f [intr]");
585 _leave(" = f [stale]");