ia64/linux-2.6.18-xen.hg

view fs/afs/cell.c @ 524:7f8b544237bf

netfront: Allow netfront in domain 0.

This is useful if your physical network device is in a utility domain.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Apr 15 15:18:58 2008 +0100 (2008-04-15)
parents 831230e53067
children
line source
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 */
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"
26 DECLARE_RWSEM(afs_proc_cells_sem);
27 LIST_HEAD(afs_proc_cells);
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;
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);
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
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;
60 _enter("%s", name);
62 BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
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 }
71 down_write(&afs_cells_sem);
73 memset(cell, 0, sizeof(struct afs_cell));
74 atomic_set(&cell->usage, 0);
76 INIT_LIST_HEAD(&cell->link);
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);
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);
88 strcpy(cell->name,name);
90 /* fill in the VL server list from the rest of the string */
91 ret = -EINVAL;
92 do {
93 unsigned a, b, c, d;
95 next = strchr(vllist, ':');
96 if (next)
97 *next++ = 0;
99 if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
100 goto badaddr;
102 if (a > 255 || b > 255 || c > 255 || d > 255)
103 goto badaddr;
105 cell->vl_addrs[cell->vl_naddrs++].s_addr =
106 htonl((a << 24) | (b << 16) | (c << 8) | d);
108 if (cell->vl_naddrs >= AFS_CELL_MAX_ADDRS)
109 break;
111 } while(vllist = next, vllist);
113 /* add a proc dir for this cell */
114 ret = afs_proc_cell_setup(cell);
115 if (ret < 0)
116 goto error;
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
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);
131 down_write(&afs_proc_cells_sem);
132 list_add_tail(&cell->proc_link, &afs_proc_cells);
133 up_write(&afs_proc_cells_sem);
135 *_cell = cell;
136 up_write(&afs_cells_sem);
138 _leave(" = 0 (%p)", cell);
139 return 0;
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() */
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;
160 _enter("");
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 }
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 }
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 }
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);
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);
201 _leave(" = %d", ret);
202 return ret;
204 } /* end afs_cell_init() */
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;
215 _enter("\"%*.*s\",", namesz, namesz, name ? name : "");
217 *_cell = NULL;
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);
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:
234 read_unlock(&afs_cells_lock);
236 if (cell)
237 ret = 0;
238 }
239 else {
240 read_lock(&afs_cells_lock);
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 }
257 read_unlock(&afs_cells_lock);
258 }
260 *_cell = cell;
261 _leave(" = %d (%p)", ret, cell);
262 return ret;
264 } /* end afs_cell_lookup() */
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;
274 write_lock(&afs_cells_lock);
276 cell = *_cell;
277 if (cell && !list_empty(&cell->link))
278 afs_get_cell(cell);
279 else
280 cell = NULL;
282 write_unlock(&afs_cells_lock);
284 return cell;
285 } /* end afs_get_cell_maybe() */
287 /*****************************************************************************/
288 /*
289 * destroy a cell record
290 */
291 void afs_put_cell(struct afs_cell *cell)
292 {
293 if (!cell)
294 return;
296 _enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
298 /* sanity check */
299 BUG_ON(atomic_read(&cell->usage) <= 0);
301 /* to prevent a race, the decrement and the dequeue must be effectively
302 * atomic */
303 write_lock(&afs_cells_lock);
305 if (likely(!atomic_dec_and_test(&cell->usage))) {
306 write_unlock(&afs_cells_lock);
307 _leave("");
308 return;
309 }
311 write_unlock(&afs_cells_lock);
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));
318 _leave(" [unused]");
319 } /* end afs_put_cell() */
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);
329 /* to prevent a race, the decrement and the dequeue must be effectively
330 * atomic */
331 write_lock(&afs_cells_lock);
333 /* sanity check */
334 BUG_ON(atomic_read(&cell->usage) != 0);
336 list_del_init(&cell->link);
338 write_unlock(&afs_cells_lock);
340 down_write(&afs_cells_sem);
342 afs_proc_cell_remove(cell);
344 down_write(&afs_proc_cells_sem);
345 list_del_init(&cell->proc_link);
346 up_write(&afs_proc_cells_sem);
348 #ifdef AFS_CACHING_SUPPORT
349 cachefs_relinquish_cookie(cell->cache, 0);
350 #endif
352 up_write(&afs_cells_sem);
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));
359 /* finish cleaning up the cell */
360 kfree(cell);
362 _leave(" [destroyed]");
363 } /* end afs_cell_destroy() */
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;
375 _enter("%p{a=%08x},", peer, ntohl(peer->addr.s_addr));
377 /* search the cell list */
378 read_lock(&afs_cells_lock);
380 list_for_each_entry(cell, &afs_cells, link) {
382 _debug("? cell %s",cell->name);
384 write_lock(&cell->sv_lock);
386 /* check the active list */
387 list_for_each_entry(server, &cell->sv_list, link) {
388 _debug("?? server %08x", ntohl(server->addr.s_addr));
390 if (memcmp(&server->addr, &peer->addr,
391 sizeof(struct in_addr)) == 0)
392 goto found_server;
393 }
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));
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);
407 write_unlock(&cell->sv_lock);
408 }
409 read_unlock(&afs_cells_lock);
411 _leave(" = -ENOENT");
412 return -ENOENT;
414 /* we found it in the graveyard - resurrect it */
415 found_dead_server:
416 list_move_tail(&server->link, &cell->sv_list);
417 afs_get_server(server);
418 afs_kafstimod_del_timer(&server->timeout);
419 spin_unlock(&cell->sv_gylock);
420 goto success;
422 /* we found it - increment its ref count and return it */
423 found_server:
424 afs_get_server(server);
426 success:
427 write_unlock(&cell->sv_lock);
428 read_unlock(&afs_cells_lock);
430 *_server = server;
431 _leave(" = 0 (s=%p c=%p)", server, cell);
432 return 0;
434 } /* end afs_server_find_by_peer() */
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 */
441 void afs_cell_purge(void)
442 {
443 struct afs_vlocation *vlocation;
444 struct afs_cell *cell;
446 _enter("");
448 afs_put_cell(afs_cell_root);
450 while (!list_empty(&afs_cells)) {
451 cell = NULL;
453 /* remove the next cell from the front of the list */
454 write_lock(&afs_cells_lock);
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 }
462 write_unlock(&afs_cells_lock);
464 if (cell) {
465 _debug("PURGING CELL %s (%d)",
466 cell->name, atomic_read(&cell->usage));
468 BUG_ON(!list_empty(&cell->sv_list));
469 BUG_ON(!list_empty(&cell->vl_list));
471 /* purge the cell's VL graveyard list */
472 _debug(" - clearing VL graveyard");
474 spin_lock(&cell->vl_gylock);
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);
482 afs_kafstimod_del_timer(&vlocation->timeout);
484 spin_unlock(&cell->vl_gylock);
486 afs_vlocation_do_timeout(vlocation);
487 /* TODO: race if move to use krxtimod instead
488 * of kafstimod */
490 spin_lock(&cell->vl_gylock);
491 }
493 spin_unlock(&cell->vl_gylock);
495 /* purge the cell's server graveyard list */
496 _debug(" - clearing server graveyard");
498 spin_lock(&cell->sv_gylock);
500 while (!list_empty(&cell->sv_graveyard)) {
501 struct afs_server *server;
503 server = list_entry(cell->sv_graveyard.next,
504 struct afs_server, link);
505 list_del_init(&server->link);
507 afs_kafstimod_del_timer(&server->timeout);
509 spin_unlock(&cell->sv_gylock);
511 afs_server_do_timeout(server);
513 spin_lock(&cell->sv_gylock);
514 }
516 spin_unlock(&cell->sv_gylock);
518 /* now the cell should be left with no references */
519 afs_cell_destroy(cell);
520 }
521 }
523 _leave("");
524 } /* end afs_cell_purge() */
526 /*****************************************************************************/
527 /*
528 * match a cell record obtained from the cache
529 */
530 #ifdef AFS_CACHING_SUPPORT
531 static 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;
537 _enter("{%s},{%s}", ccell->name, cell->name);
539 if (strncmp(ccell->name, cell->name, sizeof(ccell->name)) == 0) {
540 _leave(" = SUCCESS");
541 return CACHEFS_MATCH_SUCCESS;
542 }
544 _leave(" = FAILED");
545 return CACHEFS_MATCH_FAILED;
546 } /* end afs_cell_cache_match() */
547 #endif
549 /*****************************************************************************/
550 /*
551 * update a cell record in the cache
552 */
553 #ifdef AFS_CACHING_SUPPORT
554 static void afs_cell_cache_update(void *source, void *entry)
555 {
556 struct afs_cache_cell *ccell = entry;
557 struct afs_cell *cell = source;
559 _enter("%p,%p", source, entry);
561 strncpy(ccell->name, cell->name, sizeof(ccell->name));
563 memcpy(ccell->vl_servers,
564 cell->vl_addrs,
565 min(sizeof(ccell->vl_servers), sizeof(cell->vl_addrs)));
567 } /* end afs_cell_cache_update() */
568 #endif