blob: bfc1fd22d5b10578088aaf12e527e87c7bf163ee [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* cell.c: AFS cell and server record management
2 *
3 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
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.
10 */
11
12#include <linux/module.h>
13#include <linux/sched.h>
14#include <linux/slab.h>
15#include <rxrpc/peer.h>
16#include <rxrpc/connection.h>
17#include "volume.h"
18#include "cell.h"
19#include "server.h"
20#include "transport.h"
21#include "vlclient.h"
22#include "kafstimod.h"
23#include "super.h"
24#include "internal.h"
25
26DECLARE_RWSEM(afs_proc_cells_sem);
27LIST_HEAD(afs_proc_cells);
28
29static struct list_head afs_cells = LIST_HEAD_INIT(afs_cells);
30static DEFINE_RWLOCK(afs_cells_lock);
31static DECLARE_RWSEM(afs_cells_sem); /* add/remove serialisation */
32static struct afs_cell *afs_cell_root;
33
34#ifdef AFS_CACHING_SUPPORT
35static cachefs_match_val_t afs_cell_cache_match(void *target,
36 const void *entry);
37static void afs_cell_cache_update(void *source, void *entry);
38
39struct cachefs_index_def afs_cache_cell_index_def = {
40 .name = "cell_ix",
41 .data_size = sizeof(struct afs_cache_cell),
42 .keys[0] = { CACHEFS_INDEX_KEYS_ASCIIZ, 64 },
43 .match = afs_cell_cache_match,
44 .update = afs_cell_cache_update,
45};
46#endif
47
48/*****************************************************************************/
49/*
50 * create a cell record
51 * - "name" is the name of the cell
52 * - "vllist" is a colon separated list of IP addresses in "a.b.c.d" format
53 */
54int afs_cell_create(const char *name, char *vllist, struct afs_cell **_cell)
55{
56 struct afs_cell *cell;
57 char *next;
58 int ret;
59
60 _enter("%s", name);
61
62 BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
63
64 /* allocate and initialise a cell record */
65 cell = kmalloc(sizeof(struct afs_cell) + strlen(name) + 1, GFP_KERNEL);
66 if (!cell) {
67 _leave(" = -ENOMEM");
68 return -ENOMEM;
69 }
70
71 down_write(&afs_cells_sem);
72
73 memset(cell, 0, sizeof(struct afs_cell));
74 atomic_set(&cell->usage, 0);
75
76 INIT_LIST_HEAD(&cell->link);
77
78 rwlock_init(&cell->sv_lock);
79 INIT_LIST_HEAD(&cell->sv_list);
80 INIT_LIST_HEAD(&cell->sv_graveyard);
81 spin_lock_init(&cell->sv_gylock);
82
83 init_rwsem(&cell->vl_sem);
84 INIT_LIST_HEAD(&cell->vl_list);
85 INIT_LIST_HEAD(&cell->vl_graveyard);
86 spin_lock_init(&cell->vl_gylock);
87
88 strcpy(cell->name,name);
89
90 /* fill in the VL server list from the rest of the string */
91 ret = -EINVAL;
92 do {
93 unsigned a, b, c, d;
94
95 next = strchr(vllist, ':');
96 if (next)
97 *next++ = 0;
98
99 if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
100 goto badaddr;
101
102 if (a > 255 || b > 255 || c > 255 || d > 255)
103 goto badaddr;
104
105 cell->vl_addrs[cell->vl_naddrs++].s_addr =
106 htonl((a << 24) | (b << 16) | (c << 8) | d);
107
108 if (cell->vl_naddrs >= AFS_CELL_MAX_ADDRS)
109 break;
110
111 } while(vllist = next, vllist);
112
113 /* add a proc dir for this cell */
114 ret = afs_proc_cell_setup(cell);
115 if (ret < 0)
116 goto error;
117
118#ifdef AFS_CACHING_SUPPORT
119 /* put it up for caching */
120 cachefs_acquire_cookie(afs_cache_netfs.primary_index,
121 &afs_vlocation_cache_index_def,
122 cell,
123 &cell->cache);
124#endif
125
126 /* add to the cell lists */
127 write_lock(&afs_cells_lock);
128 list_add_tail(&cell->link, &afs_cells);
129 write_unlock(&afs_cells_lock);
130
131 down_write(&afs_proc_cells_sem);
132 list_add_tail(&cell->proc_link, &afs_proc_cells);
133 up_write(&afs_proc_cells_sem);
134
135 *_cell = cell;
136 up_write(&afs_cells_sem);
137
138 _leave(" = 0 (%p)", cell);
139 return 0;
140
141 badaddr:
142 printk(KERN_ERR "kAFS: bad VL server IP address: '%s'\n", vllist);
143 error:
144 up_write(&afs_cells_sem);
145 kfree(cell);
146 _leave(" = %d", ret);
147 return ret;
148} /* end afs_cell_create() */
149
150/*****************************************************************************/
151/*
152 * initialise the cell database from module parameters
153 */
154int afs_cell_init(char *rootcell)
155{
156 struct afs_cell *old_root, *new_root;
157 char *cp;
158 int ret;
159
160 _enter("");
161
162 if (!rootcell) {
163 /* module is loaded with no parameters, or built statically.
164 * - in the future we might initialize cell DB here.
165 */
166 _leave(" = 0 (but no root)");
167 return 0;
168 }
169
170 cp = strchr(rootcell, ':');
171 if (!cp) {
172 printk(KERN_ERR "kAFS: no VL server IP addresses specified\n");
173 _leave(" = %d (no colon)", -EINVAL);
174 return -EINVAL;
175 }
176
177 /* allocate a cell record for the root cell */
178 *cp++ = 0;
179 ret = afs_cell_create(rootcell, cp, &new_root);
180 if (ret < 0) {
181 _leave(" = %d", ret);
182 return ret;
183 }
184
185 /* as afs_put_cell() takes locks by itself, we have to do
186 * a little gymnastics to be race-free.
187 */
188 afs_get_cell(new_root);
189
190 write_lock(&afs_cells_lock);
191 while (afs_cell_root) {
192 old_root = afs_cell_root;
193 afs_cell_root = NULL;
194 write_unlock(&afs_cells_lock);
195 afs_put_cell(old_root);
196 write_lock(&afs_cells_lock);
197 }
198 afs_cell_root = new_root;
199 write_unlock(&afs_cells_lock);
200
201 _leave(" = %d", ret);
202 return ret;
203
204} /* end afs_cell_init() */
205
206/*****************************************************************************/
207/*
208 * lookup a cell record
209 */
210int afs_cell_lookup(const char *name, unsigned namesz, struct afs_cell **_cell)
211{
212 struct afs_cell *cell;
213 int ret;
214
215 _enter("\"%*.*s\",", namesz, namesz, name ? name : "");
216
217 *_cell = NULL;
218
219 if (name) {
220 /* if the cell was named, look for it in the cell record list */
221 ret = -ENOENT;
222 cell = NULL;
223 read_lock(&afs_cells_lock);
224
225 list_for_each_entry(cell, &afs_cells, link) {
226 if (strncmp(cell->name, name, namesz) == 0) {
227 afs_get_cell(cell);
228 goto found;
229 }
230 }
231 cell = NULL;
232 found:
233
234 read_unlock(&afs_cells_lock);
235
236 if (cell)
237 ret = 0;
238 }
239 else {
240 read_lock(&afs_cells_lock);
241
242 cell = afs_cell_root;
243 if (!cell) {
244 /* this should not happen unless user tries to mount
245 * when root cell is not set. Return an impossibly
246 * bizzare errno to alert the user. Things like
247 * ENOENT might be "more appropriate" but they happen
248 * for other reasons.
249 */
250 ret = -EDESTADDRREQ;
251 }
252 else {
253 afs_get_cell(cell);
254 ret = 0;
255 }
256
257 read_unlock(&afs_cells_lock);
258 }
259
260 *_cell = cell;
261 _leave(" = %d (%p)", ret, cell);
262 return ret;
263
264} /* end afs_cell_lookup() */
265
266/*****************************************************************************/
267/*
268 * try and get a cell record
269 */
270struct afs_cell *afs_get_cell_maybe(struct afs_cell **_cell)
271{
272 struct afs_cell *cell;
273
274 write_lock(&afs_cells_lock);
275
276 cell = *_cell;
277 if (cell && !list_empty(&cell->link))
278 afs_get_cell(cell);
279 else
280 cell = NULL;
281
282 write_unlock(&afs_cells_lock);
283
284 return cell;
285} /* end afs_get_cell_maybe() */
286
287/*****************************************************************************/
288/*
289 * destroy a cell record
290 */
291void afs_put_cell(struct afs_cell *cell)
292{
293 if (!cell)
294 return;
295
296 _enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
297
298 /* sanity check */
299 BUG_ON(atomic_read(&cell->usage) <= 0);
300
301 /* to prevent a race, the decrement and the dequeue must be effectively
302 * atomic */
303 write_lock(&afs_cells_lock);
304
305 if (likely(!atomic_dec_and_test(&cell->usage))) {
306 write_unlock(&afs_cells_lock);
307 _leave("");
308 return;
309 }
310
311 write_unlock(&afs_cells_lock);
312
313 BUG_ON(!list_empty(&cell->sv_list));
314 BUG_ON(!list_empty(&cell->sv_graveyard));
315 BUG_ON(!list_empty(&cell->vl_list));
316 BUG_ON(!list_empty(&cell->vl_graveyard));
317
318 _leave(" [unused]");
319} /* end afs_put_cell() */
320
321/*****************************************************************************/
322/*
323 * destroy a cell record
324 */
325static void afs_cell_destroy(struct afs_cell *cell)
326{
327 _enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
328
329 /* to prevent a race, the decrement and the dequeue must be effectively
330 * atomic */
331 write_lock(&afs_cells_lock);
332
333 /* sanity check */
334 BUG_ON(atomic_read(&cell->usage) != 0);
335
336 list_del_init(&cell->link);
337
338 write_unlock(&afs_cells_lock);
339
340 down_write(&afs_cells_sem);
341
342 afs_proc_cell_remove(cell);
343
344 down_write(&afs_proc_cells_sem);
345 list_del_init(&cell->proc_link);
346 up_write(&afs_proc_cells_sem);
347
348#ifdef AFS_CACHING_SUPPORT
349 cachefs_relinquish_cookie(cell->cache, 0);
350#endif
351
352 up_write(&afs_cells_sem);
353
354 BUG_ON(!list_empty(&cell->sv_list));
355 BUG_ON(!list_empty(&cell->sv_graveyard));
356 BUG_ON(!list_empty(&cell->vl_list));
357 BUG_ON(!list_empty(&cell->vl_graveyard));
358
359 /* finish cleaning up the cell */
360 kfree(cell);
361
362 _leave(" [destroyed]");
363} /* end afs_cell_destroy() */
364
365/*****************************************************************************/
366/*
367 * lookup the server record corresponding to an Rx RPC peer
368 */
369int afs_server_find_by_peer(const struct rxrpc_peer *peer,
370 struct afs_server **_server)
371{
372 struct afs_server *server;
373 struct afs_cell *cell;
374
375 _enter("%p{a=%08x},", peer, ntohl(peer->addr.s_addr));
376
377 /* search the cell list */
378 read_lock(&afs_cells_lock);
379
380 list_for_each_entry(cell, &afs_cells, link) {
381
382 _debug("? cell %s",cell->name);
383
384 write_lock(&cell->sv_lock);
385
386 /* check the active list */
387 list_for_each_entry(server, &cell->sv_list, link) {
388 _debug("?? server %08x", ntohl(server->addr.s_addr));
389
390 if (memcmp(&server->addr, &peer->addr,
391 sizeof(struct in_addr)) == 0)
392 goto found_server;
393 }
394
395 /* check the inactive list */
396 spin_lock(&cell->sv_gylock);
397 list_for_each_entry(server, &cell->sv_graveyard, link) {
398 _debug("?? dead server %08x",
399 ntohl(server->addr.s_addr));
400
401 if (memcmp(&server->addr, &peer->addr,
402 sizeof(struct in_addr)) == 0)
403 goto found_dead_server;
404 }
405 spin_unlock(&cell->sv_gylock);
406
407 write_unlock(&cell->sv_lock);
408 }
409 read_unlock(&afs_cells_lock);
410
411 _leave(" = -ENOENT");
412 return -ENOENT;
413
414 /* we found it in the graveyard - resurrect it */
415 found_dead_server:
Akinobu Mitaf1166292006-06-26 00:24:46 -0700416 list_move_tail(&server->link, &cell->sv_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 afs_get_server(server);
418 afs_kafstimod_del_timer(&server->timeout);
419 spin_unlock(&cell->sv_gylock);
420 goto success;
421
422 /* we found it - increment its ref count and return it */
423 found_server:
424 afs_get_server(server);
425
426 success:
427 write_unlock(&cell->sv_lock);
428 read_unlock(&afs_cells_lock);
429
430 *_server = server;
431 _leave(" = 0 (s=%p c=%p)", server, cell);
432 return 0;
433
434} /* end afs_server_find_by_peer() */
435
436/*****************************************************************************/
437/*
438 * purge in-memory cell database on module unload or afs_init() failure
439 * - the timeout daemon is stopped before calling this
440 */
441void afs_cell_purge(void)
442{
443 struct afs_vlocation *vlocation;
444 struct afs_cell *cell;
445
446 _enter("");
447
448 afs_put_cell(afs_cell_root);
449
450 while (!list_empty(&afs_cells)) {
451 cell = NULL;
452
453 /* remove the next cell from the front of the list */
454 write_lock(&afs_cells_lock);
455
456 if (!list_empty(&afs_cells)) {
457 cell = list_entry(afs_cells.next,
458 struct afs_cell, link);
459 list_del_init(&cell->link);
460 }
461
462 write_unlock(&afs_cells_lock);
463
464 if (cell) {
465 _debug("PURGING CELL %s (%d)",
466 cell->name, atomic_read(&cell->usage));
467
468 BUG_ON(!list_empty(&cell->sv_list));
469 BUG_ON(!list_empty(&cell->vl_list));
470
471 /* purge the cell's VL graveyard list */
472 _debug(" - clearing VL graveyard");
473
474 spin_lock(&cell->vl_gylock);
475
476 while (!list_empty(&cell->vl_graveyard)) {
477 vlocation = list_entry(cell->vl_graveyard.next,
478 struct afs_vlocation,
479 link);
480 list_del_init(&vlocation->link);
481
482 afs_kafstimod_del_timer(&vlocation->timeout);
483
484 spin_unlock(&cell->vl_gylock);
485
486 afs_vlocation_do_timeout(vlocation);
487 /* TODO: race if move to use krxtimod instead
488 * of kafstimod */
489
490 spin_lock(&cell->vl_gylock);
491 }
492
493 spin_unlock(&cell->vl_gylock);
494
495 /* purge the cell's server graveyard list */
496 _debug(" - clearing server graveyard");
497
498 spin_lock(&cell->sv_gylock);
499
500 while (!list_empty(&cell->sv_graveyard)) {
501 struct afs_server *server;
502
503 server = list_entry(cell->sv_graveyard.next,
504 struct afs_server, link);
505 list_del_init(&server->link);
506
507 afs_kafstimod_del_timer(&server->timeout);
508
509 spin_unlock(&cell->sv_gylock);
510
511 afs_server_do_timeout(server);
512
513 spin_lock(&cell->sv_gylock);
514 }
515
516 spin_unlock(&cell->sv_gylock);
517
518 /* now the cell should be left with no references */
519 afs_cell_destroy(cell);
520 }
521 }
522
523 _leave("");
524} /* end afs_cell_purge() */
525
526/*****************************************************************************/
527/*
528 * match a cell record obtained from the cache
529 */
530#ifdef AFS_CACHING_SUPPORT
531static cachefs_match_val_t afs_cell_cache_match(void *target,
532 const void *entry)
533{
534 const struct afs_cache_cell *ccell = entry;
535 struct afs_cell *cell = target;
536
537 _enter("{%s},{%s}", ccell->name, cell->name);
538
539 if (strncmp(ccell->name, cell->name, sizeof(ccell->name)) == 0) {
540 _leave(" = SUCCESS");
541 return CACHEFS_MATCH_SUCCESS;
542 }
543
544 _leave(" = FAILED");
545 return CACHEFS_MATCH_FAILED;
546} /* end afs_cell_cache_match() */
547#endif
548
549/*****************************************************************************/
550/*
551 * update a cell record in the cache
552 */
553#ifdef AFS_CACHING_SUPPORT
554static void afs_cell_cache_update(void *source, void *entry)
555{
556 struct afs_cache_cell *ccell = entry;
557 struct afs_cell *cell = source;
558
559 _enter("%p,%p", source, entry);
560
561 strncpy(ccell->name, cell->name, sizeof(ccell->name));
562
563 memcpy(ccell->vl_servers,
564 cell->vl_addrs,
565 min(sizeof(ccell->vl_servers), sizeof(cell->vl_addrs)));
566
567} /* end afs_cell_cache_update() */
568#endif