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1da177e4 LT |
1 | /* 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 | ||
26 | DECLARE_RWSEM(afs_proc_cells_sem); | |
27 | LIST_HEAD(afs_proc_cells); | |
28 | ||
29 | static struct list_head afs_cells = LIST_HEAD_INIT(afs_cells); | |
30 | static DEFINE_RWLOCK(afs_cells_lock); | |
31 | static DECLARE_RWSEM(afs_cells_sem); /* add/remove serialisation */ | |
32 | static struct afs_cell *afs_cell_root; | |
33 | ||
34 | #ifdef AFS_CACHING_SUPPORT | |
35 | static cachefs_match_val_t afs_cell_cache_match(void *target, | |
36 | const void *entry); | |
37 | static void afs_cell_cache_update(void *source, void *entry); | |
38 | ||
39 | struct 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 | */ | |
54 | int 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 | */ | |
154 | int 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 | */ | |
210 | int 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 | */ | |
270 | struct 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 | */ | |
291 | void 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 | */ | |
325 | static 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 | */ | |
369 | int 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: | |
416 | list_del(&server->link); | |
417 | list_add_tail(&server->link, &cell->sv_list); | |
418 | afs_get_server(server); | |
419 | afs_kafstimod_del_timer(&server->timeout); | |
420 | spin_unlock(&cell->sv_gylock); | |
421 | goto success; | |
422 | ||
423 | /* we found it - increment its ref count and return it */ | |
424 | found_server: | |
425 | afs_get_server(server); | |
426 | ||
427 | success: | |
428 | write_unlock(&cell->sv_lock); | |
429 | read_unlock(&afs_cells_lock); | |
430 | ||
431 | *_server = server; | |
432 | _leave(" = 0 (s=%p c=%p)", server, cell); | |
433 | return 0; | |
434 | ||
435 | } /* end afs_server_find_by_peer() */ | |
436 | ||
437 | /*****************************************************************************/ | |
438 | /* | |
439 | * purge in-memory cell database on module unload or afs_init() failure | |
440 | * - the timeout daemon is stopped before calling this | |
441 | */ | |
442 | void afs_cell_purge(void) | |
443 | { | |
444 | struct afs_vlocation *vlocation; | |
445 | struct afs_cell *cell; | |
446 | ||
447 | _enter(""); | |
448 | ||
449 | afs_put_cell(afs_cell_root); | |
450 | ||
451 | while (!list_empty(&afs_cells)) { | |
452 | cell = NULL; | |
453 | ||
454 | /* remove the next cell from the front of the list */ | |
455 | write_lock(&afs_cells_lock); | |
456 | ||
457 | if (!list_empty(&afs_cells)) { | |
458 | cell = list_entry(afs_cells.next, | |
459 | struct afs_cell, link); | |
460 | list_del_init(&cell->link); | |
461 | } | |
462 | ||
463 | write_unlock(&afs_cells_lock); | |
464 | ||
465 | if (cell) { | |
466 | _debug("PURGING CELL %s (%d)", | |
467 | cell->name, atomic_read(&cell->usage)); | |
468 | ||
469 | BUG_ON(!list_empty(&cell->sv_list)); | |
470 | BUG_ON(!list_empty(&cell->vl_list)); | |
471 | ||
472 | /* purge the cell's VL graveyard list */ | |
473 | _debug(" - clearing VL graveyard"); | |
474 | ||
475 | spin_lock(&cell->vl_gylock); | |
476 | ||
477 | while (!list_empty(&cell->vl_graveyard)) { | |
478 | vlocation = list_entry(cell->vl_graveyard.next, | |
479 | struct afs_vlocation, | |
480 | link); | |
481 | list_del_init(&vlocation->link); | |
482 | ||
483 | afs_kafstimod_del_timer(&vlocation->timeout); | |
484 | ||
485 | spin_unlock(&cell->vl_gylock); | |
486 | ||
487 | afs_vlocation_do_timeout(vlocation); | |
488 | /* TODO: race if move to use krxtimod instead | |
489 | * of kafstimod */ | |
490 | ||
491 | spin_lock(&cell->vl_gylock); | |
492 | } | |
493 | ||
494 | spin_unlock(&cell->vl_gylock); | |
495 | ||
496 | /* purge the cell's server graveyard list */ | |
497 | _debug(" - clearing server graveyard"); | |
498 | ||
499 | spin_lock(&cell->sv_gylock); | |
500 | ||
501 | while (!list_empty(&cell->sv_graveyard)) { | |
502 | struct afs_server *server; | |
503 | ||
504 | server = list_entry(cell->sv_graveyard.next, | |
505 | struct afs_server, link); | |
506 | list_del_init(&server->link); | |
507 | ||
508 | afs_kafstimod_del_timer(&server->timeout); | |
509 | ||
510 | spin_unlock(&cell->sv_gylock); | |
511 | ||
512 | afs_server_do_timeout(server); | |
513 | ||
514 | spin_lock(&cell->sv_gylock); | |
515 | } | |
516 | ||
517 | spin_unlock(&cell->sv_gylock); | |
518 | ||
519 | /* now the cell should be left with no references */ | |
520 | afs_cell_destroy(cell); | |
521 | } | |
522 | } | |
523 | ||
524 | _leave(""); | |
525 | } /* end afs_cell_purge() */ | |
526 | ||
527 | /*****************************************************************************/ | |
528 | /* | |
529 | * match a cell record obtained from the cache | |
530 | */ | |
531 | #ifdef AFS_CACHING_SUPPORT | |
532 | static cachefs_match_val_t afs_cell_cache_match(void *target, | |
533 | const void *entry) | |
534 | { | |
535 | const struct afs_cache_cell *ccell = entry; | |
536 | struct afs_cell *cell = target; | |
537 | ||
538 | _enter("{%s},{%s}", ccell->name, cell->name); | |
539 | ||
540 | if (strncmp(ccell->name, cell->name, sizeof(ccell->name)) == 0) { | |
541 | _leave(" = SUCCESS"); | |
542 | return CACHEFS_MATCH_SUCCESS; | |
543 | } | |
544 | ||
545 | _leave(" = FAILED"); | |
546 | return CACHEFS_MATCH_FAILED; | |
547 | } /* end afs_cell_cache_match() */ | |
548 | #endif | |
549 | ||
550 | /*****************************************************************************/ | |
551 | /* | |
552 | * update a cell record in the cache | |
553 | */ | |
554 | #ifdef AFS_CACHING_SUPPORT | |
555 | static void afs_cell_cache_update(void *source, void *entry) | |
556 | { | |
557 | struct afs_cache_cell *ccell = entry; | |
558 | struct afs_cell *cell = source; | |
559 | ||
560 | _enter("%p,%p", source, entry); | |
561 | ||
562 | strncpy(ccell->name, cell->name, sizeof(ccell->name)); | |
563 | ||
564 | memcpy(ccell->vl_servers, | |
565 | cell->vl_addrs, | |
566 | min(sizeof(ccell->vl_servers), sizeof(cell->vl_addrs))); | |
567 | ||
568 | } /* end afs_cell_cache_update() */ | |
569 | #endif |