Commit | Line | Data |
---|---|---|
03b55b9d EP |
1 | /* |
2 | * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net> | |
3 | * All rights reserved. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | */ | |
15 | ||
16 | #include <linux/blkdev.h> | |
17 | #include <linux/bio.h> | |
18 | #include <linux/dst.h> | |
19 | #include <linux/in.h> | |
20 | #include <linux/in6.h> | |
21 | #include <linux/poll.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/socket.h> | |
24 | ||
25 | #include <net/sock.h> | |
26 | ||
27 | /* | |
28 | * Export bioset is used for server block IO requests. | |
29 | */ | |
30 | static struct bio_set *dst_bio_set; | |
31 | ||
32 | int __init dst_export_init(void) | |
33 | { | |
34 | int err = -ENOMEM; | |
35 | ||
3e5510ab | 36 | dst_bio_set = bioset_create(32, sizeof(struct dst_export_priv)); |
03b55b9d EP |
37 | if (!dst_bio_set) |
38 | goto err_out_exit; | |
39 | ||
40 | return 0; | |
41 | ||
42 | err_out_exit: | |
43 | return err; | |
44 | } | |
45 | ||
46 | void dst_export_exit(void) | |
47 | { | |
48 | bioset_free(dst_bio_set); | |
49 | } | |
50 | ||
51 | /* | |
52 | * When client connects and autonegotiates with the server node, | |
53 | * its permissions are checked in a security attributes and sent | |
54 | * back. | |
55 | */ | |
56 | static unsigned int dst_check_permissions(struct dst_state *main, struct dst_state *st) | |
57 | { | |
58 | struct dst_node *n = main->node; | |
59 | struct dst_secure *sentry; | |
60 | struct dst_secure_user *s; | |
61 | struct saddr *sa = &st->ctl.addr; | |
62 | unsigned int perm = 0; | |
63 | ||
64 | mutex_lock(&n->security_lock); | |
65 | list_for_each_entry(sentry, &n->security_list, sec_entry) { | |
66 | s = &sentry->sec; | |
67 | ||
68 | if (s->addr.sa_family != sa->sa_family) | |
69 | continue; | |
70 | ||
71 | if (s->addr.sa_data_len != sa->sa_data_len) | |
72 | continue; | |
73 | ||
74 | /* | |
75 | * This '2' below is a port field. This may be very wrong to do | |
76 | * in atalk for example though. If there will be any need to extent | |
77 | * protocol to something else, I can create per-family helpers and | |
78 | * use them instead of this memcmp. | |
79 | */ | |
80 | if (memcmp(s->addr.sa_data + 2, sa->sa_data + 2, | |
81 | sa->sa_data_len - 2)) | |
82 | continue; | |
83 | ||
84 | perm = s->permissions; | |
85 | } | |
86 | mutex_unlock(&n->security_lock); | |
87 | ||
88 | return perm; | |
89 | } | |
90 | ||
91 | /* | |
92 | * Accept new client: allocate appropriate network state and check permissions. | |
93 | */ | |
94 | static struct dst_state *dst_accept_client(struct dst_state *st) | |
95 | { | |
96 | unsigned int revents = 0; | |
97 | unsigned int err_mask = POLLERR | POLLHUP | POLLRDHUP; | |
98 | unsigned int mask = err_mask | POLLIN; | |
99 | struct dst_node *n = st->node; | |
100 | int err = 0; | |
101 | struct socket *sock = NULL; | |
102 | struct dst_state *new; | |
103 | ||
104 | while (!err && !sock) { | |
105 | revents = dst_state_poll(st); | |
106 | ||
107 | if (!(revents & mask)) { | |
108 | DEFINE_WAIT(wait); | |
109 | ||
110 | for (;;) { | |
111 | prepare_to_wait(&st->thread_wait, | |
112 | &wait, TASK_INTERRUPTIBLE); | |
113 | if (!n->trans_scan_timeout || st->need_exit) | |
114 | break; | |
115 | ||
116 | revents = dst_state_poll(st); | |
117 | ||
118 | if (revents & mask) | |
119 | break; | |
120 | ||
121 | if (signal_pending(current)) | |
122 | break; | |
123 | ||
124 | /* | |
125 | * Magic HZ? Polling check above is not safe in | |
126 | * all cases (like socket reset in BH context), | |
127 | * so it is simpler just to postpone it to the | |
128 | * process context instead of implementing special | |
129 | * locking there. | |
130 | */ | |
131 | schedule_timeout(HZ); | |
132 | } | |
133 | finish_wait(&st->thread_wait, &wait); | |
134 | } | |
135 | ||
136 | err = -ECONNRESET; | |
137 | dst_state_lock(st); | |
138 | ||
139 | dprintk("%s: st: %p, revents: %x [err: %d, in: %d].\n", | |
140 | __func__, st, revents, revents & err_mask, | |
141 | revents & POLLIN); | |
142 | ||
143 | if (revents & err_mask) { | |
144 | dprintk("%s: revents: %x, socket: %p, err: %d.\n", | |
145 | __func__, revents, st->socket, err); | |
146 | err = -ECONNRESET; | |
147 | } | |
148 | ||
149 | if (!n->trans_scan_timeout || st->need_exit) | |
150 | err = -ENODEV; | |
151 | ||
152 | if (st->socket && (revents & POLLIN)) | |
153 | err = kernel_accept(st->socket, &sock, 0); | |
154 | ||
155 | dst_state_unlock(st); | |
156 | } | |
157 | ||
158 | if (err) | |
159 | goto err_out_exit; | |
160 | ||
161 | new = dst_state_alloc(st->node); | |
d0e0507a | 162 | if (IS_ERR(new)) { |
03b55b9d EP |
163 | err = -ENOMEM; |
164 | goto err_out_release; | |
165 | } | |
166 | new->socket = sock; | |
167 | ||
168 | new->ctl.addr.sa_data_len = sizeof(struct sockaddr); | |
169 | err = kernel_getpeername(sock, (struct sockaddr *)&new->ctl.addr, | |
170 | (int *)&new->ctl.addr.sa_data_len); | |
171 | if (err) | |
172 | goto err_out_put; | |
173 | ||
174 | new->permissions = dst_check_permissions(st, new); | |
175 | if (new->permissions == 0) { | |
176 | err = -EPERM; | |
177 | dst_dump_addr(sock, (struct sockaddr *)&new->ctl.addr, | |
178 | "Client is not allowed to connect"); | |
179 | goto err_out_put; | |
180 | } | |
181 | ||
182 | err = dst_poll_init(new); | |
183 | if (err) | |
184 | goto err_out_put; | |
185 | ||
186 | dst_dump_addr(sock, (struct sockaddr *)&new->ctl.addr, | |
187 | "Connected client"); | |
188 | ||
189 | return new; | |
190 | ||
191 | err_out_put: | |
192 | dst_state_put(new); | |
193 | err_out_release: | |
194 | sock_release(sock); | |
195 | err_out_exit: | |
196 | return ERR_PTR(err); | |
197 | } | |
198 | ||
199 | /* | |
200 | * Each server's block request sometime finishes. | |
201 | * Usually it happens in hard irq context of the appropriate controller, | |
202 | * so to play good with all cases we just queue BIO into the queue | |
203 | * and wake up processing thread, which gets completed request and | |
204 | * send (encrypting if needed) it back to the client (if it was a read | |
205 | * request), or sends back reply that writing succesfully completed. | |
206 | */ | |
207 | static int dst_export_process_request_queue(struct dst_state *st) | |
208 | { | |
209 | unsigned long flags; | |
210 | struct dst_export_priv *p = NULL; | |
211 | struct bio *bio; | |
212 | int err = 0; | |
213 | ||
214 | while (!list_empty(&st->request_list)) { | |
215 | spin_lock_irqsave(&st->request_lock, flags); | |
216 | if (!list_empty(&st->request_list)) { | |
217 | p = list_first_entry(&st->request_list, | |
218 | struct dst_export_priv, request_entry); | |
219 | list_del(&p->request_entry); | |
220 | } | |
221 | spin_unlock_irqrestore(&st->request_lock, flags); | |
222 | ||
223 | if (!p) | |
224 | break; | |
225 | ||
226 | bio = p->bio; | |
227 | ||
228 | if (dst_need_crypto(st->node) && (bio_data_dir(bio) == READ)) | |
229 | err = dst_export_crypto(st->node, bio); | |
230 | else | |
231 | err = dst_export_send_bio(bio); | |
232 | ||
233 | if (err) | |
234 | break; | |
235 | } | |
236 | ||
237 | return err; | |
238 | } | |
239 | ||
240 | /* | |
241 | * Cleanup export state. | |
242 | * It has to wait until all requests are finished, | |
243 | * and then free them all. | |
244 | */ | |
245 | static void dst_state_cleanup_export(struct dst_state *st) | |
246 | { | |
247 | struct dst_export_priv *p; | |
248 | unsigned long flags; | |
249 | ||
250 | /* | |
251 | * This loop waits for all pending bios to be completed and freed. | |
252 | */ | |
253 | while (atomic_read(&st->refcnt) > 1) { | |
254 | dprintk("%s: st: %p, refcnt: %d, list_empty: %d.\n", | |
255 | __func__, st, atomic_read(&st->refcnt), | |
256 | list_empty(&st->request_list)); | |
257 | wait_event_timeout(st->thread_wait, | |
258 | (atomic_read(&st->refcnt) == 1) || | |
259 | !list_empty(&st->request_list), | |
260 | HZ/2); | |
261 | ||
262 | while (!list_empty(&st->request_list)) { | |
263 | p = NULL; | |
264 | spin_lock_irqsave(&st->request_lock, flags); | |
265 | if (!list_empty(&st->request_list)) { | |
266 | p = list_first_entry(&st->request_list, | |
267 | struct dst_export_priv, request_entry); | |
268 | list_del(&p->request_entry); | |
269 | } | |
270 | spin_unlock_irqrestore(&st->request_lock, flags); | |
271 | ||
272 | if (p) | |
273 | bio_put(p->bio); | |
274 | ||
275 | dprintk("%s: st: %p, refcnt: %d, list_empty: %d, p: %p.\n", | |
276 | __func__, st, atomic_read(&st->refcnt), | |
277 | list_empty(&st->request_list), p); | |
278 | } | |
279 | } | |
280 | ||
281 | dst_state_put(st); | |
282 | } | |
283 | ||
284 | /* | |
285 | * Client accepting thread. | |
286 | * Not only accepts new connection, but also schedules receiving thread | |
287 | * and performs request completion described above. | |
288 | */ | |
289 | static int dst_accept(void *init_data, void *schedule_data) | |
290 | { | |
291 | struct dst_state *main_st = schedule_data; | |
292 | struct dst_node *n = init_data; | |
293 | struct dst_state *st; | |
294 | int err; | |
295 | ||
296 | while (n->trans_scan_timeout && !main_st->need_exit) { | |
297 | dprintk("%s: main_st: %p, n: %p.\n", __func__, main_st, n); | |
298 | st = dst_accept_client(main_st); | |
299 | if (IS_ERR(st)) | |
300 | continue; | |
301 | ||
302 | err = dst_state_schedule_receiver(st); | |
303 | if (!err) { | |
304 | while (n->trans_scan_timeout) { | |
305 | err = wait_event_interruptible_timeout(st->thread_wait, | |
306 | !list_empty(&st->request_list) || | |
307 | !n->trans_scan_timeout || | |
308 | st->need_exit, | |
309 | HZ); | |
310 | ||
311 | if (!n->trans_scan_timeout || st->need_exit) | |
312 | break; | |
313 | ||
314 | if (list_empty(&st->request_list)) | |
315 | continue; | |
316 | ||
317 | err = dst_export_process_request_queue(st); | |
318 | if (err) | |
319 | break; | |
320 | } | |
321 | ||
322 | st->need_exit = 1; | |
323 | wake_up(&st->thread_wait); | |
324 | } | |
325 | ||
326 | dst_state_cleanup_export(st); | |
327 | } | |
328 | ||
329 | dprintk("%s: freeing listening socket st: %p.\n", __func__, main_st); | |
330 | ||
331 | dst_state_lock(main_st); | |
332 | dst_poll_exit(main_st); | |
333 | dst_state_socket_release(main_st); | |
334 | dst_state_unlock(main_st); | |
335 | dst_state_put(main_st); | |
336 | dprintk("%s: freed listening socket st: %p.\n", __func__, main_st); | |
337 | ||
338 | return 0; | |
339 | } | |
340 | ||
341 | int dst_start_export(struct dst_node *n) | |
342 | { | |
343 | if (list_empty(&n->security_list)) { | |
344 | printk(KERN_ERR "You are trying to export node '%s' without security attributes.\n" | |
345 | "No clients will be allowed to connect. Exiting.\n", n->name); | |
346 | return -EINVAL; | |
347 | } | |
348 | return dst_node_trans_init(n, sizeof(struct dst_export_priv)); | |
349 | } | |
350 | ||
351 | /* | |
352 | * Initialize listening state and schedule accepting thread. | |
353 | */ | |
354 | int dst_node_init_listened(struct dst_node *n, struct dst_export_ctl *le) | |
355 | { | |
356 | struct dst_state *st; | |
357 | int err = -ENOMEM; | |
358 | struct dst_network_ctl *ctl = &le->ctl; | |
359 | ||
360 | memcpy(&n->info->net, ctl, sizeof(struct dst_network_ctl)); | |
361 | ||
362 | st = dst_state_alloc(n); | |
363 | if (IS_ERR(st)) { | |
364 | err = PTR_ERR(st); | |
365 | goto err_out_exit; | |
366 | } | |
367 | memcpy(&st->ctl, ctl, sizeof(struct dst_network_ctl)); | |
368 | ||
369 | err = dst_state_socket_create(st); | |
370 | if (err) | |
371 | goto err_out_put; | |
372 | ||
373 | st->socket->sk->sk_reuse = 1; | |
374 | ||
375 | err = kernel_bind(st->socket, (struct sockaddr *)&ctl->addr, | |
376 | ctl->addr.sa_data_len); | |
377 | if (err) | |
378 | goto err_out_socket_release; | |
379 | ||
380 | err = kernel_listen(st->socket, 1024); | |
381 | if (err) | |
382 | goto err_out_socket_release; | |
383 | n->state = st; | |
384 | ||
385 | err = dst_poll_init(st); | |
386 | if (err) | |
387 | goto err_out_socket_release; | |
388 | ||
389 | dst_state_get(st); | |
390 | ||
391 | err = thread_pool_schedule(n->pool, dst_thread_setup, | |
392 | dst_accept, st, MAX_SCHEDULE_TIMEOUT); | |
393 | if (err) | |
394 | goto err_out_poll_exit; | |
395 | ||
396 | return 0; | |
397 | ||
398 | err_out_poll_exit: | |
399 | dst_poll_exit(st); | |
400 | err_out_socket_release: | |
401 | dst_state_socket_release(st); | |
402 | err_out_put: | |
403 | dst_state_put(st); | |
404 | err_out_exit: | |
405 | n->state = NULL; | |
406 | return err; | |
407 | } | |
408 | ||
409 | /* | |
410 | * Free bio and related private data. | |
411 | * Also drop a reference counter for appropriate state, | |
412 | * which waits when there are no more block IOs in-flight. | |
413 | */ | |
414 | static void dst_bio_destructor(struct bio *bio) | |
415 | { | |
416 | struct bio_vec *bv; | |
417 | struct dst_export_priv *priv = bio->bi_private; | |
418 | int i; | |
419 | ||
420 | bio_for_each_segment(bv, bio, i) { | |
421 | if (!bv->bv_page) | |
422 | break; | |
423 | ||
424 | __free_page(bv->bv_page); | |
425 | } | |
426 | ||
3e5510ab | 427 | if (priv) |
03b55b9d | 428 | dst_state_put(priv->state); |
03b55b9d EP |
429 | bio_free(bio, dst_bio_set); |
430 | } | |
431 | ||
432 | /* | |
433 | * Block IO completion. Queue request to be sent back to | |
434 | * the client (or just confirmation). | |
435 | */ | |
436 | static void dst_bio_end_io(struct bio *bio, int err) | |
437 | { | |
438 | struct dst_export_priv *p = bio->bi_private; | |
439 | struct dst_state *st = p->state; | |
440 | unsigned long flags; | |
441 | ||
442 | spin_lock_irqsave(&st->request_lock, flags); | |
443 | list_add_tail(&p->request_entry, &st->request_list); | |
444 | spin_unlock_irqrestore(&st->request_lock, flags); | |
445 | ||
446 | wake_up(&st->thread_wait); | |
447 | } | |
448 | ||
449 | /* | |
450 | * Allocate read request for the server. | |
451 | */ | |
452 | static int dst_export_read_request(struct bio *bio, unsigned int total_size) | |
453 | { | |
454 | unsigned int size; | |
455 | struct page *page; | |
456 | int err; | |
457 | ||
458 | while (total_size) { | |
459 | err = -ENOMEM; | |
460 | page = alloc_page(GFP_KERNEL); | |
461 | if (!page) | |
462 | goto err_out_exit; | |
463 | ||
464 | size = min_t(unsigned int, PAGE_SIZE, total_size); | |
465 | ||
466 | err = bio_add_page(bio, page, size, 0); | |
467 | dprintk("%s: bio: %llu/%u, size: %u, err: %d.\n", | |
468 | __func__, (u64)bio->bi_sector, bio->bi_size, | |
469 | size, err); | |
470 | if (err <= 0) | |
471 | goto err_out_free_page; | |
472 | ||
473 | total_size -= size; | |
474 | } | |
475 | ||
476 | return 0; | |
477 | ||
478 | err_out_free_page: | |
479 | __free_page(page); | |
480 | err_out_exit: | |
481 | return err; | |
482 | } | |
483 | ||
484 | /* | |
485 | * Allocate write request for the server. | |
486 | * Should not only get pages, but also read data from the network. | |
487 | */ | |
488 | static int dst_export_write_request(struct dst_state *st, | |
489 | struct bio *bio, unsigned int total_size) | |
490 | { | |
491 | unsigned int size; | |
492 | struct page *page; | |
493 | void *data; | |
494 | int err; | |
495 | ||
496 | while (total_size) { | |
497 | err = -ENOMEM; | |
498 | page = alloc_page(GFP_KERNEL); | |
499 | if (!page) | |
500 | goto err_out_exit; | |
501 | ||
502 | data = kmap(page); | |
503 | if (!data) | |
504 | goto err_out_free_page; | |
505 | ||
506 | size = min_t(unsigned int, PAGE_SIZE, total_size); | |
507 | ||
508 | err = dst_data_recv(st, data, size); | |
509 | if (err) | |
510 | goto err_out_unmap_page; | |
511 | ||
512 | err = bio_add_page(bio, page, size, 0); | |
513 | if (err <= 0) | |
514 | goto err_out_unmap_page; | |
515 | ||
516 | kunmap(page); | |
517 | ||
518 | total_size -= size; | |
519 | } | |
520 | ||
521 | return 0; | |
522 | ||
523 | err_out_unmap_page: | |
524 | kunmap(page); | |
525 | err_out_free_page: | |
526 | __free_page(page); | |
527 | err_out_exit: | |
528 | return err; | |
529 | } | |
530 | ||
531 | /* | |
532 | * Groovy, we've gotten an IO request from the client. | |
533 | * Allocate BIO from the bioset, private data from the mempool | |
534 | * and lots of pages for IO. | |
535 | */ | |
536 | int dst_process_io(struct dst_state *st) | |
537 | { | |
538 | struct dst_node *n = st->node; | |
539 | struct dst_cmd *cmd = st->data; | |
540 | struct bio *bio; | |
541 | struct dst_export_priv *priv; | |
542 | int err = -ENOMEM; | |
543 | ||
544 | if (unlikely(!n->bdev)) { | |
545 | err = -EINVAL; | |
546 | goto err_out_exit; | |
547 | } | |
548 | ||
549 | bio = bio_alloc_bioset(GFP_KERNEL, | |
550 | PAGE_ALIGN(cmd->size) >> PAGE_SHIFT, | |
551 | dst_bio_set); | |
552 | if (!bio) | |
553 | goto err_out_exit; | |
03b55b9d | 554 | |
3e5510ab | 555 | priv = (struct dst_export_priv *)(((void *)bio) - sizeof (struct dst_export_priv)); |
03b55b9d EP |
556 | |
557 | priv->state = dst_state_get(st); | |
558 | priv->bio = bio; | |
559 | ||
560 | bio->bi_private = priv; | |
561 | bio->bi_end_io = dst_bio_end_io; | |
562 | bio->bi_destructor = dst_bio_destructor; | |
563 | bio->bi_bdev = n->bdev; | |
564 | ||
565 | /* | |
566 | * Server side is only interested in two low bits: | |
567 | * uptodate (set by itself actually) and rw block | |
568 | */ | |
569 | bio->bi_flags |= cmd->flags & 3; | |
570 | ||
571 | bio->bi_rw = cmd->rw; | |
572 | bio->bi_size = 0; | |
573 | bio->bi_sector = cmd->sector; | |
574 | ||
575 | dst_bio_to_cmd(bio, &priv->cmd, DST_IO_RESPONSE, cmd->id); | |
576 | ||
577 | priv->cmd.flags = 0; | |
578 | priv->cmd.size = cmd->size; | |
579 | ||
580 | if (bio_data_dir(bio) == WRITE) { | |
581 | err = dst_recv_cdata(st, priv->cmd.hash); | |
582 | if (err) | |
583 | goto err_out_free; | |
584 | ||
585 | err = dst_export_write_request(st, bio, cmd->size); | |
586 | if (err) | |
587 | goto err_out_free; | |
588 | ||
589 | if (dst_need_crypto(n)) | |
590 | return dst_export_crypto(n, bio); | |
591 | } else { | |
592 | err = dst_export_read_request(bio, cmd->size); | |
593 | if (err) | |
594 | goto err_out_free; | |
595 | } | |
596 | ||
597 | dprintk("%s: bio: %llu/%u, rw: %lu, dir: %lu, flags: %lx, phys: %d.\n", | |
598 | __func__, (u64)bio->bi_sector, bio->bi_size, | |
599 | bio->bi_rw, bio_data_dir(bio), | |
600 | bio->bi_flags, bio->bi_phys_segments); | |
601 | ||
602 | generic_make_request(bio); | |
603 | ||
604 | return 0; | |
605 | ||
606 | err_out_free: | |
607 | bio_put(bio); | |
608 | err_out_exit: | |
609 | return err; | |
610 | } | |
611 | ||
612 | /* | |
613 | * Ok, block IO is ready, let's send it back to the client... | |
614 | */ | |
615 | int dst_export_send_bio(struct bio *bio) | |
616 | { | |
617 | struct dst_export_priv *p = bio->bi_private; | |
618 | struct dst_state *st = p->state; | |
619 | struct dst_cmd *cmd = &p->cmd; | |
620 | int err; | |
621 | ||
622 | dprintk("%s: id: %llu, bio: %llu/%u, csize: %u, flags: %lu, rw: %lu.\n", | |
623 | __func__, cmd->id, (u64)bio->bi_sector, bio->bi_size, | |
624 | cmd->csize, bio->bi_flags, bio->bi_rw); | |
625 | ||
626 | dst_convert_cmd(cmd); | |
627 | ||
628 | dst_state_lock(st); | |
629 | if (!st->socket) { | |
630 | err = -ECONNRESET; | |
631 | goto err_out_unlock; | |
632 | } | |
633 | ||
634 | if (bio_data_dir(bio) == WRITE) { | |
635 | /* ... or just confirmation that writing has completed. */ | |
636 | cmd->size = cmd->csize = 0; | |
637 | err = dst_data_send_header(st->socket, cmd, | |
638 | sizeof(struct dst_cmd), 0); | |
639 | if (err) | |
640 | goto err_out_unlock; | |
641 | } else { | |
642 | err = dst_send_bio(st, cmd, bio); | |
643 | if (err) | |
644 | goto err_out_unlock; | |
645 | } | |
646 | ||
647 | dst_state_unlock(st); | |
648 | ||
649 | bio_put(bio); | |
650 | return 0; | |
651 | ||
652 | err_out_unlock: | |
653 | dst_state_unlock(st); | |
654 | ||
655 | bio_put(bio); | |
656 | return err; | |
657 | } |