Commit | Line | Data |
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ec26815a | 1 | /* AFS server record management |
1da177e4 LT |
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/sched.h> | |
13 | #include <linux/slab.h> | |
14 | #include <rxrpc/peer.h> | |
15 | #include <rxrpc/connection.h> | |
16 | #include "volume.h" | |
17 | #include "cell.h" | |
18 | #include "server.h" | |
19 | #include "transport.h" | |
20 | #include "vlclient.h" | |
21 | #include "kafstimod.h" | |
22 | #include "internal.h" | |
23 | ||
24 | DEFINE_SPINLOCK(afs_server_peer_lock); | |
25 | ||
26 | #define FS_SERVICE_ID 1 /* AFS Volume Location Service ID */ | |
27 | #define VL_SERVICE_ID 52 /* AFS Volume Location Service ID */ | |
28 | ||
29 | static void __afs_server_timeout(struct afs_timer *timer) | |
30 | { | |
31 | struct afs_server *server = | |
32 | list_entry(timer, struct afs_server, timeout); | |
33 | ||
34 | _debug("SERVER TIMEOUT [%p{u=%d}]", | |
35 | server, atomic_read(&server->usage)); | |
36 | ||
37 | afs_server_do_timeout(server); | |
38 | } | |
39 | ||
40 | static const struct afs_timer_ops afs_server_timer_ops = { | |
41 | .timed_out = __afs_server_timeout, | |
42 | }; | |
43 | ||
1da177e4 LT |
44 | /* |
45 | * lookup a server record in a cell | |
46 | * - TODO: search the cell's server list | |
47 | */ | |
48 | int afs_server_lookup(struct afs_cell *cell, const struct in_addr *addr, | |
49 | struct afs_server **_server) | |
50 | { | |
51 | struct afs_server *server, *active, *zombie; | |
52 | int loop; | |
53 | ||
54 | _enter("%p,%08x,", cell, ntohl(addr->s_addr)); | |
55 | ||
56 | /* allocate and initialise a server record */ | |
b593e48d | 57 | server = kzalloc(sizeof(struct afs_server), GFP_KERNEL); |
1da177e4 LT |
58 | if (!server) { |
59 | _leave(" = -ENOMEM"); | |
60 | return -ENOMEM; | |
61 | } | |
62 | ||
1da177e4 LT |
63 | atomic_set(&server->usage, 1); |
64 | ||
65 | INIT_LIST_HEAD(&server->link); | |
66 | init_rwsem(&server->sem); | |
67 | INIT_LIST_HEAD(&server->fs_callq); | |
68 | spin_lock_init(&server->fs_lock); | |
69 | INIT_LIST_HEAD(&server->cb_promises); | |
70 | spin_lock_init(&server->cb_lock); | |
71 | ||
72 | for (loop = 0; loop < AFS_SERVER_CONN_LIST_SIZE; loop++) | |
73 | server->fs_conn_cnt[loop] = 4; | |
74 | ||
75 | memcpy(&server->addr, addr, sizeof(struct in_addr)); | |
76 | server->addr.s_addr = addr->s_addr; | |
77 | ||
78 | afs_timer_init(&server->timeout, &afs_server_timer_ops); | |
79 | ||
80 | /* add to the cell */ | |
81 | write_lock(&cell->sv_lock); | |
82 | ||
83 | /* check the active list */ | |
84 | list_for_each_entry(active, &cell->sv_list, link) { | |
85 | if (active->addr.s_addr == addr->s_addr) | |
86 | goto use_active_server; | |
87 | } | |
88 | ||
89 | /* check the inactive list */ | |
90 | spin_lock(&cell->sv_gylock); | |
91 | list_for_each_entry(zombie, &cell->sv_graveyard, link) { | |
92 | if (zombie->addr.s_addr == addr->s_addr) | |
93 | goto resurrect_server; | |
94 | } | |
95 | spin_unlock(&cell->sv_gylock); | |
96 | ||
97 | afs_get_cell(cell); | |
98 | server->cell = cell; | |
99 | list_add_tail(&server->link, &cell->sv_list); | |
100 | ||
101 | write_unlock(&cell->sv_lock); | |
102 | ||
103 | *_server = server; | |
104 | _leave(" = 0 (%p)", server); | |
105 | return 0; | |
106 | ||
107 | /* found a matching active server */ | |
ec26815a | 108 | use_active_server: |
1da177e4 LT |
109 | _debug("active server"); |
110 | afs_get_server(active); | |
111 | write_unlock(&cell->sv_lock); | |
112 | ||
113 | kfree(server); | |
114 | ||
115 | *_server = active; | |
116 | _leave(" = 0 (%p)", active); | |
117 | return 0; | |
118 | ||
119 | /* found a matching server in the graveyard, so resurrect it and | |
120 | * dispose of the new record */ | |
ec26815a | 121 | resurrect_server: |
1da177e4 LT |
122 | _debug("resurrecting server"); |
123 | ||
f116629d | 124 | list_move_tail(&zombie->link, &cell->sv_list); |
1da177e4 LT |
125 | afs_get_server(zombie); |
126 | afs_kafstimod_del_timer(&zombie->timeout); | |
127 | spin_unlock(&cell->sv_gylock); | |
128 | write_unlock(&cell->sv_lock); | |
129 | ||
130 | kfree(server); | |
131 | ||
132 | *_server = zombie; | |
133 | _leave(" = 0 (%p)", zombie); | |
134 | return 0; | |
ec26815a | 135 | } |
1da177e4 | 136 | |
1da177e4 LT |
137 | /* |
138 | * destroy a server record | |
139 | * - removes from the cell list | |
140 | */ | |
141 | void afs_put_server(struct afs_server *server) | |
142 | { | |
143 | struct afs_cell *cell; | |
144 | ||
145 | if (!server) | |
146 | return; | |
147 | ||
148 | _enter("%p", server); | |
149 | ||
150 | cell = server->cell; | |
151 | ||
152 | /* sanity check */ | |
153 | BUG_ON(atomic_read(&server->usage) <= 0); | |
154 | ||
155 | /* to prevent a race, the decrement and the dequeue must be effectively | |
156 | * atomic */ | |
157 | write_lock(&cell->sv_lock); | |
158 | ||
159 | if (likely(!atomic_dec_and_test(&server->usage))) { | |
160 | write_unlock(&cell->sv_lock); | |
161 | _leave(""); | |
162 | return; | |
163 | } | |
164 | ||
165 | spin_lock(&cell->sv_gylock); | |
f116629d | 166 | list_move_tail(&server->link, &cell->sv_graveyard); |
1da177e4 LT |
167 | |
168 | /* time out in 10 secs */ | |
169 | afs_kafstimod_add_timer(&server->timeout, 10 * HZ); | |
170 | ||
171 | spin_unlock(&cell->sv_gylock); | |
172 | write_unlock(&cell->sv_lock); | |
173 | ||
174 | _leave(" [killed]"); | |
ec26815a | 175 | } |
1da177e4 | 176 | |
1da177e4 LT |
177 | /* |
178 | * timeout server record | |
179 | * - removes from the cell's graveyard if the usage count is zero | |
180 | */ | |
181 | void afs_server_do_timeout(struct afs_server *server) | |
182 | { | |
183 | struct rxrpc_peer *peer; | |
184 | struct afs_cell *cell; | |
185 | int loop; | |
186 | ||
187 | _enter("%p", server); | |
188 | ||
189 | cell = server->cell; | |
190 | ||
191 | BUG_ON(atomic_read(&server->usage) < 0); | |
192 | ||
193 | /* remove from graveyard if still dead */ | |
194 | spin_lock(&cell->vl_gylock); | |
195 | if (atomic_read(&server->usage) == 0) | |
196 | list_del_init(&server->link); | |
197 | else | |
198 | server = NULL; | |
199 | spin_unlock(&cell->vl_gylock); | |
200 | ||
201 | if (!server) { | |
202 | _leave(""); | |
203 | return; /* resurrected */ | |
204 | } | |
205 | ||
206 | /* we can now destroy it properly */ | |
207 | afs_put_cell(cell); | |
208 | ||
209 | /* uncross-point the structs under a global lock */ | |
210 | spin_lock(&afs_server_peer_lock); | |
211 | peer = server->peer; | |
212 | if (peer) { | |
213 | server->peer = NULL; | |
214 | peer->user = NULL; | |
215 | } | |
216 | spin_unlock(&afs_server_peer_lock); | |
217 | ||
218 | /* finish cleaning up the server */ | |
219 | for (loop = AFS_SERVER_CONN_LIST_SIZE - 1; loop >= 0; loop--) | |
220 | if (server->fs_conn[loop]) | |
221 | rxrpc_put_connection(server->fs_conn[loop]); | |
222 | ||
223 | if (server->vlserver) | |
224 | rxrpc_put_connection(server->vlserver); | |
225 | ||
226 | kfree(server); | |
227 | ||
228 | _leave(" [destroyed]"); | |
ec26815a | 229 | } |
1da177e4 | 230 | |
1da177e4 LT |
231 | /* |
232 | * get a callslot on a connection to the fileserver on the specified server | |
233 | */ | |
234 | int afs_server_request_callslot(struct afs_server *server, | |
235 | struct afs_server_callslot *callslot) | |
236 | { | |
237 | struct afs_server_callslot *pcallslot; | |
238 | struct rxrpc_connection *conn; | |
239 | int nconn, ret; | |
240 | ||
241 | _enter("%p,",server); | |
242 | ||
243 | INIT_LIST_HEAD(&callslot->link); | |
244 | callslot->task = current; | |
245 | callslot->conn = NULL; | |
246 | callslot->nconn = -1; | |
247 | callslot->ready = 0; | |
248 | ||
249 | ret = 0; | |
250 | conn = NULL; | |
251 | ||
252 | /* get hold of a callslot first */ | |
253 | spin_lock(&server->fs_lock); | |
254 | ||
255 | /* resurrect the server if it's death timeout has expired */ | |
256 | if (server->fs_state) { | |
257 | if (time_before(jiffies, server->fs_dead_jif)) { | |
258 | ret = server->fs_state; | |
259 | spin_unlock(&server->fs_lock); | |
260 | _leave(" = %d [still dead]", ret); | |
261 | return ret; | |
262 | } | |
263 | ||
264 | server->fs_state = 0; | |
265 | } | |
266 | ||
267 | /* try and find a connection that has spare callslots */ | |
268 | for (nconn = 0; nconn < AFS_SERVER_CONN_LIST_SIZE; nconn++) { | |
269 | if (server->fs_conn_cnt[nconn] > 0) { | |
270 | server->fs_conn_cnt[nconn]--; | |
271 | spin_unlock(&server->fs_lock); | |
272 | callslot->nconn = nconn; | |
273 | goto obtained_slot; | |
274 | } | |
275 | } | |
276 | ||
277 | /* none were available - wait interruptibly for one to become | |
278 | * available */ | |
279 | set_current_state(TASK_INTERRUPTIBLE); | |
280 | list_add_tail(&callslot->link, &server->fs_callq); | |
281 | spin_unlock(&server->fs_lock); | |
282 | ||
283 | while (!callslot->ready && !signal_pending(current)) { | |
284 | schedule(); | |
285 | set_current_state(TASK_INTERRUPTIBLE); | |
286 | } | |
287 | ||
288 | set_current_state(TASK_RUNNING); | |
289 | ||
290 | /* even if we were interrupted we may still be queued */ | |
291 | if (!callslot->ready) { | |
292 | spin_lock(&server->fs_lock); | |
293 | list_del_init(&callslot->link); | |
294 | spin_unlock(&server->fs_lock); | |
295 | } | |
296 | ||
297 | nconn = callslot->nconn; | |
298 | ||
299 | /* if interrupted, we must release any slot we also got before | |
300 | * returning an error */ | |
301 | if (signal_pending(current)) { | |
302 | ret = -EINTR; | |
303 | goto error_release; | |
304 | } | |
305 | ||
306 | /* if we were woken up with an error, then pass that error back to the | |
307 | * called */ | |
308 | if (nconn < 0) { | |
309 | _leave(" = %d", callslot->errno); | |
310 | return callslot->errno; | |
311 | } | |
312 | ||
313 | /* were we given a connection directly? */ | |
314 | if (callslot->conn) { | |
315 | /* yes - use it */ | |
316 | _leave(" = 0 (nc=%d)", nconn); | |
317 | return 0; | |
318 | } | |
319 | ||
320 | /* got a callslot, but no connection */ | |
ec26815a | 321 | obtained_slot: |
1da177e4 LT |
322 | |
323 | /* need to get hold of the RxRPC connection */ | |
324 | down_write(&server->sem); | |
325 | ||
326 | /* quick check to see if there's an outstanding error */ | |
327 | ret = server->fs_state; | |
328 | if (ret) | |
329 | goto error_release_upw; | |
330 | ||
331 | if (server->fs_conn[nconn]) { | |
332 | /* reuse an existing connection */ | |
333 | rxrpc_get_connection(server->fs_conn[nconn]); | |
334 | callslot->conn = server->fs_conn[nconn]; | |
ec26815a | 335 | } else { |
1da177e4 LT |
336 | /* create a new connection */ |
337 | ret = rxrpc_create_connection(afs_transport, | |
338 | htons(7000), | |
339 | server->addr.s_addr, | |
340 | FS_SERVICE_ID, | |
341 | NULL, | |
342 | &server->fs_conn[nconn]); | |
343 | ||
344 | if (ret < 0) | |
345 | goto error_release_upw; | |
346 | ||
347 | callslot->conn = server->fs_conn[0]; | |
348 | rxrpc_get_connection(callslot->conn); | |
349 | } | |
350 | ||
351 | up_write(&server->sem); | |
352 | ||
353 | _leave(" = 0"); | |
354 | return 0; | |
355 | ||
356 | /* handle an error occurring */ | |
ec26815a | 357 | error_release_upw: |
1da177e4 LT |
358 | up_write(&server->sem); |
359 | ||
ec26815a | 360 | error_release: |
1da177e4 LT |
361 | /* either release the callslot or pass it along to another deserving |
362 | * task */ | |
363 | spin_lock(&server->fs_lock); | |
364 | ||
365 | if (nconn < 0) { | |
366 | /* no callslot allocated */ | |
ec26815a | 367 | } else if (list_empty(&server->fs_callq)) { |
1da177e4 LT |
368 | /* no one waiting */ |
369 | server->fs_conn_cnt[nconn]++; | |
370 | spin_unlock(&server->fs_lock); | |
ec26815a | 371 | } else { |
1da177e4 LT |
372 | /* someone's waiting - dequeue them and wake them up */ |
373 | pcallslot = list_entry(server->fs_callq.next, | |
374 | struct afs_server_callslot, link); | |
375 | list_del_init(&pcallslot->link); | |
376 | ||
377 | pcallslot->errno = server->fs_state; | |
378 | if (!pcallslot->errno) { | |
379 | /* pass them out callslot details */ | |
380 | callslot->conn = xchg(&pcallslot->conn, | |
381 | callslot->conn); | |
382 | pcallslot->nconn = nconn; | |
383 | callslot->nconn = nconn = -1; | |
384 | } | |
385 | pcallslot->ready = 1; | |
386 | wake_up_process(pcallslot->task); | |
387 | spin_unlock(&server->fs_lock); | |
388 | } | |
389 | ||
390 | rxrpc_put_connection(callslot->conn); | |
391 | callslot->conn = NULL; | |
392 | ||
393 | _leave(" = %d", ret); | |
394 | return ret; | |
ec26815a | 395 | } |
1da177e4 | 396 | |
1da177e4 LT |
397 | /* |
398 | * release a callslot back to the server | |
399 | * - transfers the RxRPC connection to the next pending callslot if possible | |
400 | */ | |
401 | void afs_server_release_callslot(struct afs_server *server, | |
402 | struct afs_server_callslot *callslot) | |
403 | { | |
404 | struct afs_server_callslot *pcallslot; | |
405 | ||
406 | _enter("{ad=%08x,cnt=%u},{%d}", | |
407 | ntohl(server->addr.s_addr), | |
408 | server->fs_conn_cnt[callslot->nconn], | |
409 | callslot->nconn); | |
410 | ||
411 | BUG_ON(callslot->nconn < 0); | |
412 | ||
413 | spin_lock(&server->fs_lock); | |
414 | ||
415 | if (list_empty(&server->fs_callq)) { | |
416 | /* no one waiting */ | |
417 | server->fs_conn_cnt[callslot->nconn]++; | |
418 | spin_unlock(&server->fs_lock); | |
ec26815a | 419 | } else { |
1da177e4 LT |
420 | /* someone's waiting - dequeue them and wake them up */ |
421 | pcallslot = list_entry(server->fs_callq.next, | |
422 | struct afs_server_callslot, link); | |
423 | list_del_init(&pcallslot->link); | |
424 | ||
425 | pcallslot->errno = server->fs_state; | |
426 | if (!pcallslot->errno) { | |
427 | /* pass them out callslot details */ | |
428 | callslot->conn = xchg(&pcallslot->conn, callslot->conn); | |
429 | pcallslot->nconn = callslot->nconn; | |
430 | callslot->nconn = -1; | |
431 | } | |
432 | ||
433 | pcallslot->ready = 1; | |
434 | wake_up_process(pcallslot->task); | |
435 | spin_unlock(&server->fs_lock); | |
436 | } | |
437 | ||
438 | rxrpc_put_connection(callslot->conn); | |
439 | ||
440 | _leave(""); | |
ec26815a | 441 | } |
1da177e4 | 442 | |
1da177e4 LT |
443 | /* |
444 | * get a handle to a connection to the vlserver (volume location) on the | |
445 | * specified server | |
446 | */ | |
447 | int afs_server_get_vlconn(struct afs_server *server, | |
448 | struct rxrpc_connection **_conn) | |
449 | { | |
450 | struct rxrpc_connection *conn; | |
451 | int ret; | |
452 | ||
453 | _enter("%p,", server); | |
454 | ||
455 | ret = 0; | |
456 | conn = NULL; | |
457 | down_read(&server->sem); | |
458 | ||
459 | if (server->vlserver) { | |
460 | /* reuse an existing connection */ | |
461 | rxrpc_get_connection(server->vlserver); | |
462 | conn = server->vlserver; | |
463 | up_read(&server->sem); | |
ec26815a | 464 | } else { |
1da177e4 LT |
465 | /* create a new connection */ |
466 | up_read(&server->sem); | |
467 | down_write(&server->sem); | |
468 | if (!server->vlserver) { | |
469 | ret = rxrpc_create_connection(afs_transport, | |
470 | htons(7003), | |
471 | server->addr.s_addr, | |
472 | VL_SERVICE_ID, | |
473 | NULL, | |
474 | &server->vlserver); | |
475 | } | |
476 | if (ret == 0) { | |
477 | rxrpc_get_connection(server->vlserver); | |
478 | conn = server->vlserver; | |
479 | } | |
480 | up_write(&server->sem); | |
481 | } | |
482 | ||
483 | *_conn = conn; | |
484 | _leave(" = %d", ret); | |
485 | return ret; | |
ec26815a | 486 | } |