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perf tools: Don't clone maps from parent when synthesizing forks
[linux/fpc-iii.git] / fs / dlm / lowcomms.c
bloba5e4a221435c04bdf97e1219ca3bd022ca864e6c
1 /******************************************************************************
2 *******************************************************************************
3 **
4 ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
5 ** Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
6 **
7 ** This copyrighted material is made available to anyone wishing to use,
8 ** modify, copy, or redistribute it subject to the terms and conditions
9 ** of the GNU General Public License v.2.
10 **
11 *******************************************************************************
12 ******************************************************************************/
13
14 /*
15 * lowcomms.c
16 *
17 * This is the "low-level" comms layer.
18 *
19 * It is responsible for sending/receiving messages
20 * from other nodes in the cluster.
21 *
22 * Cluster nodes are referred to by their nodeids. nodeids are
23 * simply 32 bit numbers to the locking module - if they need to
24 * be expanded for the cluster infrastructure then that is its
25 * responsibility. It is this layer's
26 * responsibility to resolve these into IP address or
27 * whatever it needs for inter-node communication.
28 *
29 * The comms level is two kernel threads that deal mainly with
30 * the receiving of messages from other nodes and passing them
31 * up to the mid-level comms layer (which understands the
32 * message format) for execution by the locking core, and
33 * a send thread which does all the setting up of connections
34 * to remote nodes and the sending of data. Threads are not allowed
35 * to send their own data because it may cause them to wait in times
36 * of high load. Also, this way, the sending thread can collect together
37 * messages bound for one node and send them in one block.
38 *
39 * lowcomms will choose to use either TCP or SCTP as its transport layer
40 * depending on the configuration variable 'protocol'. This should be set
41 * to 0 (default) for TCP or 1 for SCTP. It should be configured using a
42 * cluster-wide mechanism as it must be the same on all nodes of the cluster
43 * for the DLM to function.
44 *
45 */
46
47 #include <asm/ioctls.h>
48 #include <net/sock.h>
49 #include <net/tcp.h>
50 #include <linux/pagemap.h>
51 #include <linux/file.h>
52 #include <linux/mutex.h>
53 #include <linux/sctp.h>
54 #include <linux/slab.h>
55 #include <net/sctp/sctp.h>
56 #include <net/ipv6.h>
57
58 #include "dlm_internal.h"
59 #include "lowcomms.h"
60 #include "midcomms.h"
61 #include "config.h"
62
63 #define NEEDED_RMEM (4*1024*1024)
64 #define CONN_HASH_SIZE 32
65
66 /* Number of messages to send before rescheduling */
67 #define MAX_SEND_MSG_COUNT 25
68
69 struct cbuf {
70 unsigned int base;
71 unsigned int len;
72 unsigned int mask;
73 };
74
75 static void cbuf_add(struct cbuf *cb, int n)
76 {
77 cb->len += n;
78 }
79
80 static int cbuf_data(struct cbuf *cb)
81 {
82 return ((cb->base + cb->len) & cb->mask);
83 }
84
85 static void cbuf_init(struct cbuf *cb, int size)
86 {
87 cb->base = cb->len = 0;
88 cb->mask = size-1;
89 }
90
91 static void cbuf_eat(struct cbuf *cb, int n)
92 {
93 cb->len -= n;
94 cb->base += n;
95 cb->base &= cb->mask;
96 }
97
98 static bool cbuf_empty(struct cbuf *cb)
99 {
100 return cb->len == 0;
101 }
102
103 struct connection {
104 struct socket *sock; /* NULL if not connected */
105 uint32_t nodeid; /* So we know who we are in the list */
106 struct mutex sock_mutex;
107 unsigned long flags;
108 #define CF_READ_PENDING 1
109 #define CF_WRITE_PENDING 2
110 #define CF_INIT_PENDING 4
111 #define CF_IS_OTHERCON 5
112 #define CF_CLOSE 6
113 #define CF_APP_LIMITED 7
114 #define CF_CLOSING 8
115 struct list_head writequeue; /* List of outgoing writequeue_entries */
116 spinlock_t writequeue_lock;
117 int (*rx_action) (struct connection *); /* What to do when active */
118 void (*connect_action) (struct connection *); /* What to do to connect */
119 struct page *rx_page;
120 struct cbuf cb;
121 int retries;
122 #define MAX_CONNECT_RETRIES 3
123 struct hlist_node list;
124 struct connection *othercon;
125 struct work_struct rwork; /* Receive workqueue */
126 struct work_struct swork; /* Send workqueue */
127 };
128 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
129
130 /* An entry waiting to be sent */
131 struct writequeue_entry {
132 struct list_head list;
133 struct page *page;
134 int offset;
135 int len;
136 int end;
137 int users;
138 struct connection *con;
139 };
140
141 struct dlm_node_addr {
142 struct list_head list;
143 int nodeid;
144 int addr_count;
145 int curr_addr_index;
146 struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
147 };
148
149 static struct listen_sock_callbacks {
150 void (*sk_error_report)(struct sock *);
151 void (*sk_data_ready)(struct sock *);
152 void (*sk_state_change)(struct sock *);
153 void (*sk_write_space)(struct sock *);
154 } listen_sock;
155
156 static LIST_HEAD(dlm_node_addrs);
157 static DEFINE_SPINLOCK(dlm_node_addrs_spin);
158
159 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
160 static int dlm_local_count;
161 static int dlm_allow_conn;
162
163 /* Work queues */
164 static struct workqueue_struct *recv_workqueue;
165 static struct workqueue_struct *send_workqueue;
166
167 static struct hlist_head connection_hash[CONN_HASH_SIZE];
168 static DEFINE_MUTEX(connections_lock);
169 static struct kmem_cache *con_cache;
170
171 static void process_recv_sockets(struct work_struct *work);
172 static void process_send_sockets(struct work_struct *work);
173
174
175 /* This is deliberately very simple because most clusters have simple
176 sequential nodeids, so we should be able to go straight to a connection
177 struct in the array */
178 static inline int nodeid_hash(int nodeid)
179 {
180 return nodeid & (CONN_HASH_SIZE-1);
181 }
182
183 static struct connection *__find_con(int nodeid)
184 {
185 int r;
186 struct connection *con;
187
188 r = nodeid_hash(nodeid);
189
190 hlist_for_each_entry(con, &connection_hash[r], list) {
191 if (con->nodeid == nodeid)
192 return con;
193 }
194 return NULL;
195 }
196
197 /*
198 * If 'allocation' is zero then we don't attempt to create a new
199 * connection structure for this node.
200 */
201 static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
202 {
203 struct connection *con = NULL;
204 int r;
205
206 con = __find_con(nodeid);
207 if (con || !alloc)
208 return con;
209
210 con = kmem_cache_zalloc(con_cache, alloc);
211 if (!con)
212 return NULL;
213
214 r = nodeid_hash(nodeid);
215 hlist_add_head(&con->list, &connection_hash[r]);
216
217 con->nodeid = nodeid;
218 mutex_init(&con->sock_mutex);
219 INIT_LIST_HEAD(&con->writequeue);
220 spin_lock_init(&con->writequeue_lock);
221 INIT_WORK(&con->swork, process_send_sockets);
222 INIT_WORK(&con->rwork, process_recv_sockets);
223
224 /* Setup action pointers for child sockets */
225 if (con->nodeid) {
226 struct connection *zerocon = __find_con(0);
227
228 con->connect_action = zerocon->connect_action;
229 if (!con->rx_action)
230 con->rx_action = zerocon->rx_action;
231 }
232
233 return con;
234 }
235
236 /* Loop round all connections */
237 static void foreach_conn(void (*conn_func)(struct connection *c))
238 {
239 int i;
240 struct hlist_node *n;
241 struct connection *con;
242
243 for (i = 0; i < CONN_HASH_SIZE; i++) {
244 hlist_for_each_entry_safe(con, n, &connection_hash[i], list)
245 conn_func(con);
246 }
247 }
248
249 static struct connection *nodeid2con(int nodeid, gfp_t allocation)
250 {
251 struct connection *con;
252
253 mutex_lock(&connections_lock);
254 con = __nodeid2con(nodeid, allocation);
255 mutex_unlock(&connections_lock);
256
257 return con;
258 }
259
260 static struct dlm_node_addr *find_node_addr(int nodeid)
261 {
262 struct dlm_node_addr *na;
263
264 list_for_each_entry(na, &dlm_node_addrs, list) {
265 if (na->nodeid == nodeid)
266 return na;
267 }
268 return NULL;
269 }
270
271 static int addr_compare(struct sockaddr_storage *x, struct sockaddr_storage *y)
272 {
273 switch (x->ss_family) {
274 case AF_INET: {
275 struct sockaddr_in *sinx = (struct sockaddr_in *)x;
276 struct sockaddr_in *siny = (struct sockaddr_in *)y;
277 if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr)
278 return 0;
279 if (sinx->sin_port != siny->sin_port)
280 return 0;
281 break;
282 }
283 case AF_INET6: {
284 struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x;
285 struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y;
286 if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr))
287 return 0;
288 if (sinx->sin6_port != siny->sin6_port)
289 return 0;
290 break;
291 }
292 default:
293 return 0;
294 }
295 return 1;
296 }
297
298 static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
299 struct sockaddr *sa_out, bool try_new_addr)
300 {
301 struct sockaddr_storage sas;
302 struct dlm_node_addr *na;
303
304 if (!dlm_local_count)
305 return -1;
306
307 spin_lock(&dlm_node_addrs_spin);
308 na = find_node_addr(nodeid);
309 if (na && na->addr_count) {
310 memcpy(&sas, na->addr[na->curr_addr_index],
311 sizeof(struct sockaddr_storage));
312
313 if (try_new_addr) {
314 na->curr_addr_index++;
315 if (na->curr_addr_index == na->addr_count)
316 na->curr_addr_index = 0;
317 }
318 }
319 spin_unlock(&dlm_node_addrs_spin);
320
321 if (!na)
322 return -EEXIST;
323
324 if (!na->addr_count)
325 return -ENOENT;
326
327 if (sas_out)
328 memcpy(sas_out, &sas, sizeof(struct sockaddr_storage));
329
330 if (!sa_out)
331 return 0;
332
333 if (dlm_local_addr[0]->ss_family == AF_INET) {
334 struct sockaddr_in *in4 = (struct sockaddr_in *) &sas;
335 struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out;
336 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
337 } else {
338 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) &sas;
339 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) sa_out;
340 ret6->sin6_addr = in6->sin6_addr;
341 }
342
343 return 0;
344 }
345
346 static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
347 {
348 struct dlm_node_addr *na;
349 int rv = -EEXIST;
350 int addr_i;
351
352 spin_lock(&dlm_node_addrs_spin);
353 list_for_each_entry(na, &dlm_node_addrs, list) {
354 if (!na->addr_count)
355 continue;
356
357 for (addr_i = 0; addr_i < na->addr_count; addr_i++) {
358 if (addr_compare(na->addr[addr_i], addr)) {
359 *nodeid = na->nodeid;
360 rv = 0;
361 goto unlock;
362 }
363 }
364 }
365 unlock:
366 spin_unlock(&dlm_node_addrs_spin);
367 return rv;
368 }
369
370 int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
371 {
372 struct sockaddr_storage *new_addr;
373 struct dlm_node_addr *new_node, *na;
374
375 new_node = kzalloc(sizeof(struct dlm_node_addr), GFP_NOFS);
376 if (!new_node)
377 return -ENOMEM;
378
379 new_addr = kzalloc(sizeof(struct sockaddr_storage), GFP_NOFS);
380 if (!new_addr) {
381 kfree(new_node);
382 return -ENOMEM;
383 }
384
385 memcpy(new_addr, addr, len);
386
387 spin_lock(&dlm_node_addrs_spin);
388 na = find_node_addr(nodeid);
389 if (!na) {
390 new_node->nodeid = nodeid;
391 new_node->addr[0] = new_addr;
392 new_node->addr_count = 1;
393 list_add(&new_node->list, &dlm_node_addrs);
394 spin_unlock(&dlm_node_addrs_spin);
395 return 0;
396 }
397
398 if (na->addr_count >= DLM_MAX_ADDR_COUNT) {
399 spin_unlock(&dlm_node_addrs_spin);
400 kfree(new_addr);
401 kfree(new_node);
402 return -ENOSPC;
403 }
404
405 na->addr[na->addr_count++] = new_addr;
406 spin_unlock(&dlm_node_addrs_spin);
407 kfree(new_node);
408 return 0;
409 }
410
411 /* Data available on socket or listen socket received a connect */
412 static void lowcomms_data_ready(struct sock *sk)
413 {
414 struct connection *con;
415
416 read_lock_bh(&sk->sk_callback_lock);
417 con = sock2con(sk);
418 if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
419 queue_work(recv_workqueue, &con->rwork);
420 read_unlock_bh(&sk->sk_callback_lock);
421 }
422
423 static void lowcomms_write_space(struct sock *sk)
424 {
425 struct connection *con;
426
427 read_lock_bh(&sk->sk_callback_lock);
428 con = sock2con(sk);
429 if (!con)
430 goto out;
431
432 clear_bit(SOCK_NOSPACE, &con->sock->flags);
433
434 if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
435 con->sock->sk->sk_write_pending--;
436 clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags);
437 }
438
439 queue_work(send_workqueue, &con->swork);
440 out:
441 read_unlock_bh(&sk->sk_callback_lock);
442 }
443
444 static inline void lowcomms_connect_sock(struct connection *con)
445 {
446 if (test_bit(CF_CLOSE, &con->flags))
447 return;
448 queue_work(send_workqueue, &con->swork);
449 cond_resched();
450 }
451
452 static void lowcomms_state_change(struct sock *sk)
453 {
454 /* SCTP layer is not calling sk_data_ready when the connection
455 * is done, so we catch the signal through here. Also, it
456 * doesn't switch socket state when entering shutdown, so we
457 * skip the write in that case.
458 */
459 if (sk->sk_shutdown) {
460 if (sk->sk_shutdown == RCV_SHUTDOWN)
461 lowcomms_data_ready(sk);
462 } else if (sk->sk_state == TCP_ESTABLISHED) {
463 lowcomms_write_space(sk);
464 }
465 }
466
467 int dlm_lowcomms_connect_node(int nodeid)
468 {
469 struct connection *con;
470
471 if (nodeid == dlm_our_nodeid())
472 return 0;
473
474 con = nodeid2con(nodeid, GFP_NOFS);
475 if (!con)
476 return -ENOMEM;
477 lowcomms_connect_sock(con);
478 return 0;
479 }
480
481 static void lowcomms_error_report(struct sock *sk)
482 {
483 struct connection *con;
484 struct sockaddr_storage saddr;
485 void (*orig_report)(struct sock *) = NULL;
486
487 read_lock_bh(&sk->sk_callback_lock);
488 con = sock2con(sk);
489 if (con == NULL)
490 goto out;
491
492 orig_report = listen_sock.sk_error_report;
493 if (con->sock == NULL ||
494 kernel_getpeername(con->sock, (struct sockaddr *)&saddr) < 0) {
495 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
496 "sending to node %d, port %d, "
497 "sk_err=%d/%d\n", dlm_our_nodeid(),
498 con->nodeid, dlm_config.ci_tcp_port,
499 sk->sk_err, sk->sk_err_soft);
500 } else if (saddr.ss_family == AF_INET) {
501 struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr;
502
503 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
504 "sending to node %d at %pI4, port %d, "
505 "sk_err=%d/%d\n", dlm_our_nodeid(),
506 con->nodeid, &sin4->sin_addr.s_addr,
507 dlm_config.ci_tcp_port, sk->sk_err,
508 sk->sk_err_soft);
509 } else {
510 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&saddr;
511
512 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
513 "sending to node %d at %u.%u.%u.%u, "
514 "port %d, sk_err=%d/%d\n", dlm_our_nodeid(),
515 con->nodeid, sin6->sin6_addr.s6_addr32[0],
516 sin6->sin6_addr.s6_addr32[1],
517 sin6->sin6_addr.s6_addr32[2],
518 sin6->sin6_addr.s6_addr32[3],
519 dlm_config.ci_tcp_port, sk->sk_err,
520 sk->sk_err_soft);
521 }
522 out:
523 read_unlock_bh(&sk->sk_callback_lock);
524 if (orig_report)
525 orig_report(sk);
526 }
527
528 /* Note: sk_callback_lock must be locked before calling this function. */
529 static void save_listen_callbacks(struct socket *sock)
530 {
531 struct sock *sk = sock->sk;
532
533 listen_sock.sk_data_ready = sk->sk_data_ready;
534 listen_sock.sk_state_change = sk->sk_state_change;
535 listen_sock.sk_write_space = sk->sk_write_space;
536 listen_sock.sk_error_report = sk->sk_error_report;
537 }
538
539 static void restore_callbacks(struct socket *sock)
540 {
541 struct sock *sk = sock->sk;
542
543 write_lock_bh(&sk->sk_callback_lock);
544 sk->sk_user_data = NULL;
545 sk->sk_data_ready = listen_sock.sk_data_ready;
546 sk->sk_state_change = listen_sock.sk_state_change;
547 sk->sk_write_space = listen_sock.sk_write_space;
548 sk->sk_error_report = listen_sock.sk_error_report;
549 write_unlock_bh(&sk->sk_callback_lock);
550 }
551
552 /* Make a socket active */
553 static void add_sock(struct socket *sock, struct connection *con)
554 {
555 struct sock *sk = sock->sk;
556
557 write_lock_bh(&sk->sk_callback_lock);
558 con->sock = sock;
559
560 sk->sk_user_data = con;
561 /* Install a data_ready callback */
562 sk->sk_data_ready = lowcomms_data_ready;
563 sk->sk_write_space = lowcomms_write_space;
564 sk->sk_state_change = lowcomms_state_change;
565 sk->sk_allocation = GFP_NOFS;
566 sk->sk_error_report = lowcomms_error_report;
567 write_unlock_bh(&sk->sk_callback_lock);
568 }
569
570 /* Add the port number to an IPv6 or 4 sockaddr and return the address
571 length */
572 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
573 int *addr_len)
574 {
575 saddr->ss_family = dlm_local_addr[0]->ss_family;
576 if (saddr->ss_family == AF_INET) {
577 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
578 in4_addr->sin_port = cpu_to_be16(port);
579 *addr_len = sizeof(struct sockaddr_in);
580 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
581 } else {
582 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
583 in6_addr->sin6_port = cpu_to_be16(port);
584 *addr_len = sizeof(struct sockaddr_in6);
585 }
586 memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
587 }
588
589 /* Close a remote connection and tidy up */
590 static void close_connection(struct connection *con, bool and_other,
591 bool tx, bool rx)
592 {
593 bool closing = test_and_set_bit(CF_CLOSING, &con->flags);
594
595 if (tx && !closing && cancel_work_sync(&con->swork)) {
596 log_print("canceled swork for node %d", con->nodeid);
597 clear_bit(CF_WRITE_PENDING, &con->flags);
598 }
599 if (rx && !closing && cancel_work_sync(&con->rwork)) {
600 log_print("canceled rwork for node %d", con->nodeid);
601 clear_bit(CF_READ_PENDING, &con->flags);
602 }
603
604 mutex_lock(&con->sock_mutex);
605 if (con->sock) {
606 restore_callbacks(con->sock);
607 sock_release(con->sock);
608 con->sock = NULL;
609 }
610 if (con->othercon && and_other) {
611 /* Will only re-enter once. */
612 close_connection(con->othercon, false, true, true);
613 }
614 if (con->rx_page) {
615 __free_page(con->rx_page);
616 con->rx_page = NULL;
617 }
618
619 con->retries = 0;
620 mutex_unlock(&con->sock_mutex);
621 clear_bit(CF_CLOSING, &con->flags);
622 }
623
624 /* Data received from remote end */
625 static int receive_from_sock(struct connection *con)
626 {
627 int ret = 0;
628 struct msghdr msg = {};
629 struct kvec iov[2];
630 unsigned len;
631 int r;
632 int call_again_soon = 0;
633 int nvec;
634
635 mutex_lock(&con->sock_mutex);
636
637 if (con->sock == NULL) {
638 ret = -EAGAIN;
639 goto out_close;
640 }
641 if (con->nodeid == 0) {
642 ret = -EINVAL;
643 goto out_close;
644 }
645
646 if (con->rx_page == NULL) {
647 /*
648 * This doesn't need to be atomic, but I think it should
649 * improve performance if it is.
650 */
651 con->rx_page = alloc_page(GFP_ATOMIC);
652 if (con->rx_page == NULL)
653 goto out_resched;
654 cbuf_init(&con->cb, PAGE_SIZE);
655 }
656
657 /*
658 * iov[0] is the bit of the circular buffer between the current end
659 * point (cb.base + cb.len) and the end of the buffer.
660 */
661 iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
662 iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
663 iov[1].iov_len = 0;
664 nvec = 1;
665
666 /*
667 * iov[1] is the bit of the circular buffer between the start of the
668 * buffer and the start of the currently used section (cb.base)
669 */
670 if (cbuf_data(&con->cb) >= con->cb.base) {
671 iov[0].iov_len = PAGE_SIZE - cbuf_data(&con->cb);
672 iov[1].iov_len = con->cb.base;
673 iov[1].iov_base = page_address(con->rx_page);
674 nvec = 2;
675 }
676 len = iov[0].iov_len + iov[1].iov_len;
677 iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, iov, nvec, len);
678
679 r = ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
680 if (ret <= 0)
681 goto out_close;
682 else if (ret == len)
683 call_again_soon = 1;
684
685 cbuf_add(&con->cb, ret);
686 ret = dlm_process_incoming_buffer(con->nodeid,
687 page_address(con->rx_page),
688 con->cb.base, con->cb.len,
689 PAGE_SIZE);
690 if (ret == -EBADMSG) {
691 log_print("lowcomms: addr=%p, base=%u, len=%u, read=%d",
692 page_address(con->rx_page), con->cb.base,
693 con->cb.len, r);
694 }
695 if (ret < 0)
696 goto out_close;
697 cbuf_eat(&con->cb, ret);
698
699 if (cbuf_empty(&con->cb) && !call_again_soon) {
700 __free_page(con->rx_page);
701 con->rx_page = NULL;
702 }
703
704 if (call_again_soon)
705 goto out_resched;
706 mutex_unlock(&con->sock_mutex);
707 return 0;
708
709 out_resched:
710 if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
711 queue_work(recv_workqueue, &con->rwork);
712 mutex_unlock(&con->sock_mutex);
713 return -EAGAIN;
714
715 out_close:
716 mutex_unlock(&con->sock_mutex);
717 if (ret != -EAGAIN) {
718 close_connection(con, true, true, false);
719 /* Reconnect when there is something to send */
720 }
721 /* Don't return success if we really got EOF */
722 if (ret == 0)
723 ret = -EAGAIN;
724
725 return ret;
726 }
727
728 /* Listening socket is busy, accept a connection */
729 static int tcp_accept_from_sock(struct connection *con)
730 {
731 int result;
732 struct sockaddr_storage peeraddr;
733 struct socket *newsock;
734 int len;
735 int nodeid;
736 struct connection *newcon;
737 struct connection *addcon;
738
739 mutex_lock(&connections_lock);
740 if (!dlm_allow_conn) {
741 mutex_unlock(&connections_lock);
742 return -1;
743 }
744 mutex_unlock(&connections_lock);
745
746 mutex_lock_nested(&con->sock_mutex, 0);
747
748 if (!con->sock) {
749 mutex_unlock(&con->sock_mutex);
750 return -ENOTCONN;
751 }
752
753 result = kernel_accept(con->sock, &newsock, O_NONBLOCK);
754 if (result < 0)
755 goto accept_err;
756
757 /* Get the connected socket's peer */
758 memset(&peeraddr, 0, sizeof(peeraddr));
759 len = newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr, 2);
760 if (len < 0) {
761 result = -ECONNABORTED;
762 goto accept_err;
763 }
764
765 /* Get the new node's NODEID */
766 make_sockaddr(&peeraddr, 0, &len);
767 if (addr_to_nodeid(&peeraddr, &nodeid)) {
768 unsigned char *b=(unsigned char *)&peeraddr;
769 log_print("connect from non cluster node");
770 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
771 b, sizeof(struct sockaddr_storage));
772 sock_release(newsock);
773 mutex_unlock(&con->sock_mutex);
774 return -1;
775 }
776
777 log_print("got connection from %d", nodeid);
778
779 /* Check to see if we already have a connection to this node. This
780 * could happen if the two nodes initiate a connection at roughly
781 * the same time and the connections cross on the wire.
782 * In this case we store the incoming one in "othercon"
783 */
784 newcon = nodeid2con(nodeid, GFP_NOFS);
785 if (!newcon) {
786 result = -ENOMEM;
787 goto accept_err;
788 }
789 mutex_lock_nested(&newcon->sock_mutex, 1);
790 if (newcon->sock) {
791 struct connection *othercon = newcon->othercon;
792
793 if (!othercon) {
794 othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
795 if (!othercon) {
796 log_print("failed to allocate incoming socket");
797 mutex_unlock(&newcon->sock_mutex);
798 result = -ENOMEM;
799 goto accept_err;
800 }
801 othercon->nodeid = nodeid;
802 othercon->rx_action = receive_from_sock;
803 mutex_init(&othercon->sock_mutex);
804 INIT_LIST_HEAD(&othercon->writequeue);
805 spin_lock_init(&othercon->writequeue_lock);
806 INIT_WORK(&othercon->swork, process_send_sockets);
807 INIT_WORK(&othercon->rwork, process_recv_sockets);
808 set_bit(CF_IS_OTHERCON, &othercon->flags);
809 }
810 mutex_lock_nested(&othercon->sock_mutex, 2);
811 if (!othercon->sock) {
812 newcon->othercon = othercon;
813 add_sock(newsock, othercon);
814 addcon = othercon;
815 mutex_unlock(&othercon->sock_mutex);
816 }
817 else {
818 printk("Extra connection from node %d attempted\n", nodeid);
819 result = -EAGAIN;
820 mutex_unlock(&othercon->sock_mutex);
821 mutex_unlock(&newcon->sock_mutex);
822 goto accept_err;
823 }
824 }
825 else {
826 newcon->rx_action = receive_from_sock;
827 /* accept copies the sk after we've saved the callbacks, so we
828 don't want to save them a second time or comm errors will
829 result in calling sk_error_report recursively. */
830 add_sock(newsock, newcon);
831 addcon = newcon;
832 }
833
834 mutex_unlock(&newcon->sock_mutex);
835
836 /*
837 * Add it to the active queue in case we got data
838 * between processing the accept adding the socket
839 * to the read_sockets list
840 */
841 if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
842 queue_work(recv_workqueue, &addcon->rwork);
843 mutex_unlock(&con->sock_mutex);
844
845 return 0;
846
847 accept_err:
848 mutex_unlock(&con->sock_mutex);
849 if (newsock)
850 sock_release(newsock);
851
852 if (result != -EAGAIN)
853 log_print("error accepting connection from node: %d", result);
854 return result;
855 }
856
857 static int sctp_accept_from_sock(struct connection *con)
858 {
859 /* Check that the new node is in the lockspace */
860 struct sctp_prim prim;
861 int nodeid;
862 int prim_len, ret;
863 int addr_len;
864 struct connection *newcon;
865 struct connection *addcon;
866 struct socket *newsock;
867
868 mutex_lock(&connections_lock);
869 if (!dlm_allow_conn) {
870 mutex_unlock(&connections_lock);
871 return -1;
872 }
873 mutex_unlock(&connections_lock);
874
875 mutex_lock_nested(&con->sock_mutex, 0);
876
877 ret = kernel_accept(con->sock, &newsock, O_NONBLOCK);
878 if (ret < 0)
879 goto accept_err;
880
881 memset(&prim, 0, sizeof(struct sctp_prim));
882 prim_len = sizeof(struct sctp_prim);
883
884 ret = kernel_getsockopt(newsock, IPPROTO_SCTP, SCTP_PRIMARY_ADDR,
885 (char *)&prim, &prim_len);
886 if (ret < 0) {
887 log_print("getsockopt/sctp_primary_addr failed: %d", ret);
888 goto accept_err;
889 }
890
891 make_sockaddr(&prim.ssp_addr, 0, &addr_len);
892 ret = addr_to_nodeid(&prim.ssp_addr, &nodeid);
893 if (ret) {
894 unsigned char *b = (unsigned char *)&prim.ssp_addr;
895
896 log_print("reject connect from unknown addr");
897 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
898 b, sizeof(struct sockaddr_storage));
899 goto accept_err;
900 }
901
902 newcon = nodeid2con(nodeid, GFP_NOFS);
903 if (!newcon) {
904 ret = -ENOMEM;
905 goto accept_err;
906 }
907
908 mutex_lock_nested(&newcon->sock_mutex, 1);
909
910 if (newcon->sock) {
911 struct connection *othercon = newcon->othercon;
912
913 if (!othercon) {
914 othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
915 if (!othercon) {
916 log_print("failed to allocate incoming socket");
917 mutex_unlock(&newcon->sock_mutex);
918 ret = -ENOMEM;
919 goto accept_err;
920 }
921 othercon->nodeid = nodeid;
922 othercon->rx_action = receive_from_sock;
923 mutex_init(&othercon->sock_mutex);
924 INIT_LIST_HEAD(&othercon->writequeue);
925 spin_lock_init(&othercon->writequeue_lock);
926 INIT_WORK(&othercon->swork, process_send_sockets);
927 INIT_WORK(&othercon->rwork, process_recv_sockets);
928 set_bit(CF_IS_OTHERCON, &othercon->flags);
929 }
930 mutex_lock_nested(&othercon->sock_mutex, 2);
931 if (!othercon->sock) {
932 newcon->othercon = othercon;
933 add_sock(newsock, othercon);
934 addcon = othercon;
935 mutex_unlock(&othercon->sock_mutex);
936 } else {
937 printk("Extra connection from node %d attempted\n", nodeid);
938 ret = -EAGAIN;
939 mutex_unlock(&othercon->sock_mutex);
940 mutex_unlock(&newcon->sock_mutex);
941 goto accept_err;
942 }
943 } else {
944 newcon->rx_action = receive_from_sock;
945 add_sock(newsock, newcon);
946 addcon = newcon;
947 }
948
949 log_print("connected to %d", nodeid);
950
951 mutex_unlock(&newcon->sock_mutex);
952
953 /*
954 * Add it to the active queue in case we got data
955 * between processing the accept adding the socket
956 * to the read_sockets list
957 */
958 if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
959 queue_work(recv_workqueue, &addcon->rwork);
960 mutex_unlock(&con->sock_mutex);
961
962 return 0;
963
964 accept_err:
965 mutex_unlock(&con->sock_mutex);
966 if (newsock)
967 sock_release(newsock);
968 if (ret != -EAGAIN)
969 log_print("error accepting connection from node: %d", ret);
970
971 return ret;
972 }
973
974 static void free_entry(struct writequeue_entry *e)
975 {
976 __free_page(e->page);
977 kfree(e);
978 }
979
980 /*
981 * writequeue_entry_complete - try to delete and free write queue entry
982 * @e: write queue entry to try to delete
983 * @completed: bytes completed
984 *
985 * writequeue_lock must be held.
986 */
987 static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
988 {
989 e->offset += completed;
990 e->len -= completed;
991
992 if (e->len == 0 && e->users == 0) {
993 list_del(&e->list);
994 free_entry(e);
995 }
996 }
997
998 /*
999 * sctp_bind_addrs - bind a SCTP socket to all our addresses
1000 */
1001 static int sctp_bind_addrs(struct connection *con, uint16_t port)
1002 {
1003 struct sockaddr_storage localaddr;
1004 int i, addr_len, result = 0;
1005
1006 for (i = 0; i < dlm_local_count; i++) {
1007 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
1008 make_sockaddr(&localaddr, port, &addr_len);
1009
1010 if (!i)
1011 result = kernel_bind(con->sock,
1012 (struct sockaddr *)&localaddr,
1013 addr_len);
1014 else
1015 result = kernel_setsockopt(con->sock, SOL_SCTP,
1016 SCTP_SOCKOPT_BINDX_ADD,
1017 (char *)&localaddr, addr_len);
1018
1019 if (result < 0) {
1020 log_print("Can't bind to %d addr number %d, %d.\n",
1021 port, i + 1, result);
1022 break;
1023 }
1024 }
1025 return result;
1026 }
1027
1028 /* Initiate an SCTP association.
1029 This is a special case of send_to_sock() in that we don't yet have a
1030 peeled-off socket for this association, so we use the listening socket
1031 and add the primary IP address of the remote node.
1032 */
1033 static void sctp_connect_to_sock(struct connection *con)
1034 {
1035 struct sockaddr_storage daddr;
1036 int one = 1;
1037 int result;
1038 int addr_len;
1039 struct socket *sock;
1040 struct timeval tv = { .tv_sec = 5, .tv_usec = 0 };
1041
1042 if (con->nodeid == 0) {
1043 log_print("attempt to connect sock 0 foiled");
1044 return;
1045 }
1046
1047 mutex_lock(&con->sock_mutex);
1048
1049 /* Some odd races can cause double-connects, ignore them */
1050 if (con->retries++ > MAX_CONNECT_RETRIES)
1051 goto out;
1052
1053 if (con->sock) {
1054 log_print("node %d already connected.", con->nodeid);
1055 goto out;
1056 }
1057
1058 memset(&daddr, 0, sizeof(daddr));
1059 result = nodeid_to_addr(con->nodeid, &daddr, NULL, true);
1060 if (result < 0) {
1061 log_print("no address for nodeid %d", con->nodeid);
1062 goto out;
1063 }
1064
1065 /* Create a socket to communicate with */
1066 result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1067 SOCK_STREAM, IPPROTO_SCTP, &sock);
1068 if (result < 0)
1069 goto socket_err;
1070
1071 con->rx_action = receive_from_sock;
1072 con->connect_action = sctp_connect_to_sock;
1073 add_sock(sock, con);
1074
1075 /* Bind to all addresses. */
1076 if (sctp_bind_addrs(con, 0))
1077 goto bind_err;
1078
1079 make_sockaddr(&daddr, dlm_config.ci_tcp_port, &addr_len);
1080
1081 log_print("connecting to %d", con->nodeid);
1082
1083 /* Turn off Nagle's algorithm */
1084 kernel_setsockopt(sock, SOL_SCTP, SCTP_NODELAY, (char *)&one,
1085 sizeof(one));
1086
1087 /*
1088 * Make sock->ops->connect() function return in specified time,
1089 * since O_NONBLOCK argument in connect() function does not work here,
1090 * then, we should restore the default value of this attribute.
1091 */
1092 kernel_setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&tv,
1093 sizeof(tv));
1094 result = sock->ops->connect(sock, (struct sockaddr *)&daddr, addr_len,
1095 0);
1096 memset(&tv, 0, sizeof(tv));
1097 kernel_setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&tv,
1098 sizeof(tv));
1099
1100 if (result == -EINPROGRESS)
1101 result = 0;
1102 if (result == 0)
1103 goto out;
1104
1105 bind_err:
1106 con->sock = NULL;
1107 sock_release(sock);
1108
1109 socket_err:
1110 /*
1111 * Some errors are fatal and this list might need adjusting. For other
1112 * errors we try again until the max number of retries is reached.
1113 */
1114 if (result != -EHOSTUNREACH &&
1115 result != -ENETUNREACH &&
1116 result != -ENETDOWN &&
1117 result != -EINVAL &&
1118 result != -EPROTONOSUPPORT) {
1119 log_print("connect %d try %d error %d", con->nodeid,
1120 con->retries, result);
1121 mutex_unlock(&con->sock_mutex);
1122 msleep(1000);
1123 lowcomms_connect_sock(con);
1124 return;
1125 }
1126
1127 out:
1128 mutex_unlock(&con->sock_mutex);
1129 }
1130
1131 /* Connect a new socket to its peer */
1132 static void tcp_connect_to_sock(struct connection *con)
1133 {
1134 struct sockaddr_storage saddr, src_addr;
1135 int addr_len;
1136 struct socket *sock = NULL;
1137 int one = 1;
1138 int result;
1139
1140 if (con->nodeid == 0) {
1141 log_print("attempt to connect sock 0 foiled");
1142 return;
1143 }
1144
1145 mutex_lock(&con->sock_mutex);
1146 if (con->retries++ > MAX_CONNECT_RETRIES)
1147 goto out;
1148
1149 /* Some odd races can cause double-connects, ignore them */
1150 if (con->sock)
1151 goto out;
1152
1153 /* Create a socket to communicate with */
1154 result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1155 SOCK_STREAM, IPPROTO_TCP, &sock);
1156 if (result < 0)
1157 goto out_err;
1158
1159 memset(&saddr, 0, sizeof(saddr));
1160 result = nodeid_to_addr(con->nodeid, &saddr, NULL, false);
1161 if (result < 0) {
1162 log_print("no address for nodeid %d", con->nodeid);
1163 goto out_err;
1164 }
1165
1166 con->rx_action = receive_from_sock;
1167 con->connect_action = tcp_connect_to_sock;
1168 add_sock(sock, con);
1169
1170 /* Bind to our cluster-known address connecting to avoid
1171 routing problems */
1172 memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
1173 make_sockaddr(&src_addr, 0, &addr_len);
1174 result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
1175 addr_len);
1176 if (result < 0) {
1177 log_print("could not bind for connect: %d", result);
1178 /* This *may* not indicate a critical error */
1179 }
1180
1181 make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
1182
1183 log_print("connecting to %d", con->nodeid);
1184
1185 /* Turn off Nagle's algorithm */
1186 kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1187 sizeof(one));
1188
1189 result = sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
1190 O_NONBLOCK);
1191 if (result == -EINPROGRESS)
1192 result = 0;
1193 if (result == 0)
1194 goto out;
1195
1196 out_err:
1197 if (con->sock) {
1198 sock_release(con->sock);
1199 con->sock = NULL;
1200 } else if (sock) {
1201 sock_release(sock);
1202 }
1203 /*
1204 * Some errors are fatal and this list might need adjusting. For other
1205 * errors we try again until the max number of retries is reached.
1206 */
1207 if (result != -EHOSTUNREACH &&
1208 result != -ENETUNREACH &&
1209 result != -ENETDOWN &&
1210 result != -EINVAL &&
1211 result != -EPROTONOSUPPORT) {
1212 log_print("connect %d try %d error %d", con->nodeid,
1213 con->retries, result);
1214 mutex_unlock(&con->sock_mutex);
1215 msleep(1000);
1216 lowcomms_connect_sock(con);
1217 return;
1218 }
1219 out:
1220 mutex_unlock(&con->sock_mutex);
1221 return;
1222 }
1223
1224 static struct socket *tcp_create_listen_sock(struct connection *con,
1225 struct sockaddr_storage *saddr)
1226 {
1227 struct socket *sock = NULL;
1228 int result = 0;
1229 int one = 1;
1230 int addr_len;
1231
1232 if (dlm_local_addr[0]->ss_family == AF_INET)
1233 addr_len = sizeof(struct sockaddr_in);
1234 else
1235 addr_len = sizeof(struct sockaddr_in6);
1236
1237 /* Create a socket to communicate with */
1238 result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1239 SOCK_STREAM, IPPROTO_TCP, &sock);
1240 if (result < 0) {
1241 log_print("Can't create listening comms socket");
1242 goto create_out;
1243 }
1244
1245 /* Turn off Nagle's algorithm */
1246 kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1247 sizeof(one));
1248
1249 result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
1250 (char *)&one, sizeof(one));
1251
1252 if (result < 0) {
1253 log_print("Failed to set SO_REUSEADDR on socket: %d", result);
1254 }
1255 write_lock_bh(&sock->sk->sk_callback_lock);
1256 sock->sk->sk_user_data = con;
1257 save_listen_callbacks(sock);
1258 con->rx_action = tcp_accept_from_sock;
1259 con->connect_action = tcp_connect_to_sock;
1260 write_unlock_bh(&sock->sk->sk_callback_lock);
1261
1262 /* Bind to our port */
1263 make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
1264 result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
1265 if (result < 0) {
1266 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
1267 sock_release(sock);
1268 sock = NULL;
1269 con->sock = NULL;
1270 goto create_out;
1271 }
1272 result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
1273 (char *)&one, sizeof(one));
1274 if (result < 0) {
1275 log_print("Set keepalive failed: %d", result);
1276 }
1277
1278 result = sock->ops->listen(sock, 5);
1279 if (result < 0) {
1280 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
1281 sock_release(sock);
1282 sock = NULL;
1283 goto create_out;
1284 }
1285
1286 create_out:
1287 return sock;
1288 }
1289
1290 /* Get local addresses */
1291 static void init_local(void)
1292 {
1293 struct sockaddr_storage sas, *addr;
1294 int i;
1295
1296 dlm_local_count = 0;
1297 for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
1298 if (dlm_our_addr(&sas, i))
1299 break;
1300
1301 addr = kmemdup(&sas, sizeof(*addr), GFP_NOFS);
1302 if (!addr)
1303 break;
1304 dlm_local_addr[dlm_local_count++] = addr;
1305 }
1306 }
1307
1308 /* Initialise SCTP socket and bind to all interfaces */
1309 static int sctp_listen_for_all(void)
1310 {
1311 struct socket *sock = NULL;
1312 int result = -EINVAL;
1313 struct connection *con = nodeid2con(0, GFP_NOFS);
1314 int bufsize = NEEDED_RMEM;
1315 int one = 1;
1316
1317 if (!con)
1318 return -ENOMEM;
1319
1320 log_print("Using SCTP for communications");
1321
1322 result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1323 SOCK_STREAM, IPPROTO_SCTP, &sock);
1324 if (result < 0) {
1325 log_print("Can't create comms socket, check SCTP is loaded");
1326 goto out;
1327 }
1328
1329 result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
1330 (char *)&bufsize, sizeof(bufsize));
1331 if (result)
1332 log_print("Error increasing buffer space on socket %d", result);
1333
1334 result = kernel_setsockopt(sock, SOL_SCTP, SCTP_NODELAY, (char *)&one,
1335 sizeof(one));
1336 if (result < 0)
1337 log_print("Could not set SCTP NODELAY error %d\n", result);
1338
1339 write_lock_bh(&sock->sk->sk_callback_lock);
1340 /* Init con struct */
1341 sock->sk->sk_user_data = con;
1342 save_listen_callbacks(sock);
1343 con->sock = sock;
1344 con->sock->sk->sk_data_ready = lowcomms_data_ready;
1345 con->rx_action = sctp_accept_from_sock;
1346 con->connect_action = sctp_connect_to_sock;
1347
1348 write_unlock_bh(&sock->sk->sk_callback_lock);
1349
1350 /* Bind to all addresses. */
1351 if (sctp_bind_addrs(con, dlm_config.ci_tcp_port))
1352 goto create_delsock;
1353
1354 result = sock->ops->listen(sock, 5);
1355 if (result < 0) {
1356 log_print("Can't set socket listening");
1357 goto create_delsock;
1358 }
1359
1360 return 0;
1361
1362 create_delsock:
1363 sock_release(sock);
1364 con->sock = NULL;
1365 out:
1366 return result;
1367 }
1368
1369 static int tcp_listen_for_all(void)
1370 {
1371 struct socket *sock = NULL;
1372 struct connection *con = nodeid2con(0, GFP_NOFS);
1373 int result = -EINVAL;
1374
1375 if (!con)
1376 return -ENOMEM;
1377
1378 /* We don't support multi-homed hosts */
1379 if (dlm_local_addr[1] != NULL) {
1380 log_print("TCP protocol can't handle multi-homed hosts, "
1381 "try SCTP");
1382 return -EINVAL;
1383 }
1384
1385 log_print("Using TCP for communications");
1386
1387 sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1388 if (sock) {
1389 add_sock(sock, con);
1390 result = 0;
1391 }
1392 else {
1393 result = -EADDRINUSE;
1394 }
1395
1396 return result;
1397 }
1398
1399
1400
1401 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1402 gfp_t allocation)
1403 {
1404 struct writequeue_entry *entry;
1405
1406 entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1407 if (!entry)
1408 return NULL;
1409
1410 entry->page = alloc_page(allocation);
1411 if (!entry->page) {
1412 kfree(entry);
1413 return NULL;
1414 }
1415
1416 entry->offset = 0;
1417 entry->len = 0;
1418 entry->end = 0;
1419 entry->users = 0;
1420 entry->con = con;
1421
1422 return entry;
1423 }
1424
1425 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1426 {
1427 struct connection *con;
1428 struct writequeue_entry *e;
1429 int offset = 0;
1430
1431 con = nodeid2con(nodeid, allocation);
1432 if (!con)
1433 return NULL;
1434
1435 spin_lock(&con->writequeue_lock);
1436 e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1437 if ((&e->list == &con->writequeue) ||
1438 (PAGE_SIZE - e->end < len)) {
1439 e = NULL;
1440 } else {
1441 offset = e->end;
1442 e->end += len;
1443 e->users++;
1444 }
1445 spin_unlock(&con->writequeue_lock);
1446
1447 if (e) {
1448 got_one:
1449 *ppc = page_address(e->page) + offset;
1450 return e;
1451 }
1452
1453 e = new_writequeue_entry(con, allocation);
1454 if (e) {
1455 spin_lock(&con->writequeue_lock);
1456 offset = e->end;
1457 e->end += len;
1458 e->users++;
1459 list_add_tail(&e->list, &con->writequeue);
1460 spin_unlock(&con->writequeue_lock);
1461 goto got_one;
1462 }
1463 return NULL;
1464 }
1465
1466 void dlm_lowcomms_commit_buffer(void *mh)
1467 {
1468 struct writequeue_entry *e = (struct writequeue_entry *)mh;
1469 struct connection *con = e->con;
1470 int users;
1471
1472 spin_lock(&con->writequeue_lock);
1473 users = --e->users;
1474 if (users)
1475 goto out;
1476 e->len = e->end - e->offset;
1477 spin_unlock(&con->writequeue_lock);
1478
1479 queue_work(send_workqueue, &con->swork);
1480 return;
1481
1482 out:
1483 spin_unlock(&con->writequeue_lock);
1484 return;
1485 }
1486
1487 /* Send a message */
1488 static void send_to_sock(struct connection *con)
1489 {
1490 int ret = 0;
1491 const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1492 struct writequeue_entry *e;
1493 int len, offset;
1494 int count = 0;
1495
1496 mutex_lock(&con->sock_mutex);
1497 if (con->sock == NULL)
1498 goto out_connect;
1499
1500 spin_lock(&con->writequeue_lock);
1501 for (;;) {
1502 e = list_entry(con->writequeue.next, struct writequeue_entry,
1503 list);
1504 if ((struct list_head *) e == &con->writequeue)
1505 break;
1506
1507 len = e->len;
1508 offset = e->offset;
1509 BUG_ON(len == 0 && e->users == 0);
1510 spin_unlock(&con->writequeue_lock);
1511
1512 ret = 0;
1513 if (len) {
1514 ret = kernel_sendpage(con->sock, e->page, offset, len,
1515 msg_flags);
1516 if (ret == -EAGAIN || ret == 0) {
1517 if (ret == -EAGAIN &&
1518 test_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags) &&
1519 !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
1520 /* Notify TCP that we're limited by the
1521 * application window size.
1522 */
1523 set_bit(SOCK_NOSPACE, &con->sock->flags);
1524 con->sock->sk->sk_write_pending++;
1525 }
1526 cond_resched();
1527 goto out;
1528 } else if (ret < 0)
1529 goto send_error;
1530 }
1531
1532 /* Don't starve people filling buffers */
1533 if (++count >= MAX_SEND_MSG_COUNT) {
1534 cond_resched();
1535 count = 0;
1536 }
1537
1538 spin_lock(&con->writequeue_lock);
1539 writequeue_entry_complete(e, ret);
1540 }
1541 spin_unlock(&con->writequeue_lock);
1542 out:
1543 mutex_unlock(&con->sock_mutex);
1544 return;
1545
1546 send_error:
1547 mutex_unlock(&con->sock_mutex);
1548 close_connection(con, true, false, true);
1549 /* Requeue the send work. When the work daemon runs again, it will try
1550 a new connection, then call this function again. */
1551 queue_work(send_workqueue, &con->swork);
1552 return;
1553
1554 out_connect:
1555 mutex_unlock(&con->sock_mutex);
1556 queue_work(send_workqueue, &con->swork);
1557 cond_resched();
1558 }
1559
1560 static void clean_one_writequeue(struct connection *con)
1561 {
1562 struct writequeue_entry *e, *safe;
1563
1564 spin_lock(&con->writequeue_lock);
1565 list_for_each_entry_safe(e, safe, &con->writequeue, list) {
1566 list_del(&e->list);
1567 free_entry(e);
1568 }
1569 spin_unlock(&con->writequeue_lock);
1570 }
1571
1572 /* Called from recovery when it knows that a node has
1573 left the cluster */
1574 int dlm_lowcomms_close(int nodeid)
1575 {
1576 struct connection *con;
1577 struct dlm_node_addr *na;
1578
1579 log_print("closing connection to node %d", nodeid);
1580 con = nodeid2con(nodeid, 0);
1581 if (con) {
1582 set_bit(CF_CLOSE, &con->flags);
1583 close_connection(con, true, true, true);
1584 clean_one_writequeue(con);
1585 }
1586
1587 spin_lock(&dlm_node_addrs_spin);
1588 na = find_node_addr(nodeid);
1589 if (na) {
1590 list_del(&na->list);
1591 while (na->addr_count--)
1592 kfree(na->addr[na->addr_count]);
1593 kfree(na);
1594 }
1595 spin_unlock(&dlm_node_addrs_spin);
1596
1597 return 0;
1598 }
1599
1600 /* Receive workqueue function */
1601 static void process_recv_sockets(struct work_struct *work)
1602 {
1603 struct connection *con = container_of(work, struct connection, rwork);
1604 int err;
1605
1606 clear_bit(CF_READ_PENDING, &con->flags);
1607 do {
1608 err = con->rx_action(con);
1609 } while (!err);
1610 }
1611
1612 /* Send workqueue function */
1613 static void process_send_sockets(struct work_struct *work)
1614 {
1615 struct connection *con = container_of(work, struct connection, swork);
1616
1617 clear_bit(CF_WRITE_PENDING, &con->flags);
1618 if (con->sock == NULL) /* not mutex protected so check it inside too */
1619 con->connect_action(con);
1620 if (!list_empty(&con->writequeue))
1621 send_to_sock(con);
1622 }
1623
1624
1625 /* Discard all entries on the write queues */
1626 static void clean_writequeues(void)
1627 {
1628 foreach_conn(clean_one_writequeue);
1629 }
1630
1631 static void work_stop(void)
1632 {
1633 destroy_workqueue(recv_workqueue);
1634 destroy_workqueue(send_workqueue);
1635 }
1636
1637 static int work_start(void)
1638 {
1639 recv_workqueue = alloc_workqueue("dlm_recv",
1640 WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1641 if (!recv_workqueue) {
1642 log_print("can't start dlm_recv");
1643 return -ENOMEM;
1644 }
1645
1646 send_workqueue = alloc_workqueue("dlm_send",
1647 WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1648 if (!send_workqueue) {
1649 log_print("can't start dlm_send");
1650 destroy_workqueue(recv_workqueue);
1651 return -ENOMEM;
1652 }
1653
1654 return 0;
1655 }
1656
1657 static void _stop_conn(struct connection *con, bool and_other)
1658 {
1659 mutex_lock(&con->sock_mutex);
1660 set_bit(CF_CLOSE, &con->flags);
1661 set_bit(CF_READ_PENDING, &con->flags);
1662 set_bit(CF_WRITE_PENDING, &con->flags);
1663 if (con->sock && con->sock->sk) {
1664 write_lock_bh(&con->sock->sk->sk_callback_lock);
1665 con->sock->sk->sk_user_data = NULL;
1666 write_unlock_bh(&con->sock->sk->sk_callback_lock);
1667 }
1668 if (con->othercon && and_other)
1669 _stop_conn(con->othercon, false);
1670 mutex_unlock(&con->sock_mutex);
1671 }
1672
1673 static void stop_conn(struct connection *con)
1674 {
1675 _stop_conn(con, true);
1676 }
1677
1678 static void free_conn(struct connection *con)
1679 {
1680 close_connection(con, true, true, true);
1681 if (con->othercon)
1682 kmem_cache_free(con_cache, con->othercon);
1683 hlist_del(&con->list);
1684 kmem_cache_free(con_cache, con);
1685 }
1686
1687 static void work_flush(void)
1688 {
1689 int ok;
1690 int i;
1691 struct hlist_node *n;
1692 struct connection *con;
1693
1694 flush_workqueue(recv_workqueue);
1695 flush_workqueue(send_workqueue);
1696 do {
1697 ok = 1;
1698 foreach_conn(stop_conn);
1699 flush_workqueue(recv_workqueue);
1700 flush_workqueue(send_workqueue);
1701 for (i = 0; i < CONN_HASH_SIZE && ok; i++) {
1702 hlist_for_each_entry_safe(con, n,
1703 &connection_hash[i], list) {
1704 ok &= test_bit(CF_READ_PENDING, &con->flags);
1705 ok &= test_bit(CF_WRITE_PENDING, &con->flags);
1706 if (con->othercon) {
1707 ok &= test_bit(CF_READ_PENDING,
1708 &con->othercon->flags);
1709 ok &= test_bit(CF_WRITE_PENDING,
1710 &con->othercon->flags);
1711 }
1712 }
1713 }
1714 } while (!ok);
1715 }
1716
1717 void dlm_lowcomms_stop(void)
1718 {
1719 /* Set all the flags to prevent any
1720 socket activity.
1721 */
1722 mutex_lock(&connections_lock);
1723 dlm_allow_conn = 0;
1724 mutex_unlock(&connections_lock);
1725 work_flush();
1726 clean_writequeues();
1727 foreach_conn(free_conn);
1728 work_stop();
1729
1730 kmem_cache_destroy(con_cache);
1731 }
1732
1733 int dlm_lowcomms_start(void)
1734 {
1735 int error = -EINVAL;
1736 struct connection *con;
1737 int i;
1738
1739 for (i = 0; i < CONN_HASH_SIZE; i++)
1740 INIT_HLIST_HEAD(&connection_hash[i]);
1741
1742 init_local();
1743 if (!dlm_local_count) {
1744 error = -ENOTCONN;
1745 log_print("no local IP address has been set");
1746 goto fail;
1747 }
1748
1749 error = -ENOMEM;
1750 con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1751 __alignof__(struct connection), 0,
1752 NULL);
1753 if (!con_cache)
1754 goto fail;
1755
1756 error = work_start();
1757 if (error)
1758 goto fail_destroy;
1759
1760 dlm_allow_conn = 1;
1761
1762 /* Start listening */
1763 if (dlm_config.ci_protocol == 0)
1764 error = tcp_listen_for_all();
1765 else
1766 error = sctp_listen_for_all();
1767 if (error)
1768 goto fail_unlisten;
1769
1770 return 0;
1771
1772 fail_unlisten:
1773 dlm_allow_conn = 0;
1774 con = nodeid2con(0,0);
1775 if (con) {
1776 close_connection(con, false, true, true);
1777 kmem_cache_free(con_cache, con);
1778 }
1779 fail_destroy:
1780 kmem_cache_destroy(con_cache);
1781 fail:
1782 return error;
1783 }
1784
1785 void dlm_lowcomms_exit(void)
1786 {
1787 struct dlm_node_addr *na, *safe;
1788
1789 spin_lock(&dlm_node_addrs_spin);
1790 list_for_each_entry_safe(na, safe, &dlm_node_addrs, list) {
1791 list_del(&na->list);
1792 while (na->addr_count--)
1793 kfree(na->addr[na->addr_count]);
1794 kfree(na);
1795 }
1796 spin_unlock(&dlm_node_addrs_spin);
1797 }
Linux with added FPC-III support