1// SPDX-License-Identifier: GPL-2.0-only
2/******************************************************************************
3*******************************************************************************
4**
5** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
6** Copyright (C) 2004-2021 Red Hat, Inc. All rights reserved.
7**
8**
9*******************************************************************************
10******************************************************************************/
11
12/*
13 * midcomms.c
14 *
15 * This is the appallingly named "mid-level" comms layer. It takes care about
16 * deliver an on application layer "reliable" communication above the used
17 * lowcomms transport layer.
18 *
19 * How it works:
20 *
21 * Each nodes keeps track of all send DLM messages in send_queue with a sequence
22 * number. The receive will send an DLM_ACK message back for every DLM message
23 * received at the other side. If a reconnect happens in lowcomms we will send
24 * all unacknowledged dlm messages again. The receiving side might drop any already
25 * received message by comparing sequence numbers.
26 *
27 * How version detection works:
28 *
29 * Due the fact that dlm has pre-configured node addresses on every side
30 * it is in it's nature that every side connects at starts to transmit
31 * dlm messages which ends in a race. However DLM_RCOM_NAMES, DLM_RCOM_STATUS
32 * and their replies are the first messages which are exchanges. Due backwards
33 * compatibility these messages are not covered by the midcomms re-transmission
34 * layer. These messages have their own re-transmission handling in the dlm
35 * application layer. The version field of every node will be set on these RCOM
36 * messages as soon as they arrived and the node isn't yet part of the nodes
37 * hash. There exists also logic to detect version mismatched if something weird
38 * going on or the first messages isn't an expected one.
39 *
40 * Termination:
41 *
42 * The midcomms layer does a 4 way handshake for termination on DLM protocol
43 * like TCP supports it with half-closed socket support. SCTP doesn't support
44 * half-closed socket, so we do it on DLM layer. Also socket shutdown() can be
45 * interrupted by .e.g. tcp reset itself. Additional there exists the othercon
46 * paradigm in lowcomms which cannot be easily without breaking backwards
47 * compatibility. A node cannot send anything to another node when a DLM_FIN
48 * message was send. There exists additional logic to print a warning if
49 * DLM wants to do it. There exists a state handling like RFC 793 but reduced
50 * to termination only. The event "member removal event" describes the cluster
51 * manager removed the node from internal lists, at this point DLM does not
52 * send any message to the other node. There exists two cases:
53 *
54 * 1. The cluster member was removed and we received a FIN
55 * OR
56 * 2. We received a FIN but the member was not removed yet
57 *
58 * One of these cases will do the CLOSE_WAIT to LAST_ACK change.
59 *
60 *
61 * +---------+
62 * | CLOSED |
63 * +---------+
64 * | add member/receive RCOM version
65 * | detection msg
66 * V
67 * +---------+
68 * | ESTAB |
69 * +---------+
70 * CLOSE | | rcv FIN
71 * ------- | | -------
72 * +---------+ snd FIN / \ snd ACK +---------+
73 * | FIN |<----------------- ------------------>| CLOSE |
74 * | WAIT-1 |------------------ | WAIT |
75 * +---------+ rcv FIN \ +---------+
76 * | rcv ACK of FIN ------- | CLOSE | member
77 * | -------------- snd ACK | ------- | removal
78 * V x V snd FIN V event
79 * +---------+ +---------+ +---------+
80 * |FINWAIT-2| | CLOSING | | LAST-ACK|
81 * +---------+ +---------+ +---------+
82 * | rcv ACK of FIN | rcv ACK of FIN |
83 * | rcv FIN -------------- | -------------- |
84 * | ------- x V x V
85 * \ snd ACK +---------+ +---------+
86 * ------------------------>| CLOSED | | CLOSED |
87 * +---------+ +---------+
88 *
89 * NOTE: any state can interrupted by midcomms_close() and state will be
90 * switched to CLOSED in case of fencing. There exists also some timeout
91 * handling when we receive the version detection RCOM messages which is
92 * made by observation.
93 *
94 * Future improvements:
95 *
96 * There exists some known issues/improvements of the dlm handling. Some
97 * of them should be done in a next major dlm version bump which makes
98 * it incompatible with previous versions.
99 *
100 * Unaligned memory access:
101 *
102 * There exists cases when the dlm message buffer length is not aligned
103 * to 8 byte. However seems nobody detected any problem with it. This
104 * can be fixed in the next major version bump of dlm.
105 *
106 * Version detection:
107 *
108 * The version detection and how it's done is related to backwards
109 * compatibility. There exists better ways to make a better handling.
110 * However this should be changed in the next major version bump of dlm.
111 *
112 * Tail Size checking:
113 *
114 * There exists a message tail payload in e.g. DLM_MSG however we don't
115 * check it against the message length yet regarding to the receive buffer
116 * length. That need to be validated.
117 *
118 * Fencing bad nodes:
119 *
120 * At timeout places or weird sequence number behaviours we should send
121 * a fencing request to the cluster manager.
122 */
123
124/* Debug switch to enable a 5 seconds sleep waiting of a termination.
125 * This can be useful to test fencing while termination is running.
126 * This requires a setup with only gfs2 as dlm user, so that the
127 * last umount will terminate the connection.
128 *
129 * However it became useful to test, while the 5 seconds block in umount
130 * just press the reset button. In a lot of dropping the termination
131 * process can could take several seconds.
132 */
133#define DLM_DEBUG_FENCE_TERMINATION 0
134
135#include <trace/events/dlm.h>
136#include <net/tcp.h>
137
138#include "dlm_internal.h"
139#include "lowcomms.h"
140#include "config.h"
141#include "memory.h"
142#include "lock.h"
143#include "util.h"
144#include "midcomms.h"
145
146/* init value for sequence numbers for testing purpose only e.g. overflows */
147#define DLM_SEQ_INIT 0
148/* 5 seconds wait to sync ending of dlm */
149#define DLM_SHUTDOWN_TIMEOUT msecs_to_jiffies(5000)
150#define DLM_VERSION_NOT_SET 0
151#define DLM_SEND_ACK_BACK_MSG_THRESHOLD 32
152#define DLM_RECV_ACK_BACK_MSG_THRESHOLD (DLM_SEND_ACK_BACK_MSG_THRESHOLD * 8)
153
154struct midcomms_node {
155 int nodeid;
156 uint32_t version;
157 atomic_t seq_send;
158 atomic_t seq_next;
159 /* These queues are unbound because we cannot drop any message in dlm.
160 * We could send a fence signal for a specific node to the cluster
161 * manager if queues hits some maximum value, however this handling
162 * not supported yet.
163 */
164 struct list_head send_queue;
165 spinlock_t send_queue_lock;
166 atomic_t send_queue_cnt;
167#define DLM_NODE_FLAG_CLOSE 1
168#define DLM_NODE_FLAG_STOP_TX 2
169#define DLM_NODE_FLAG_STOP_RX 3
170 atomic_t ulp_delivered;
171 unsigned long flags;
172 wait_queue_head_t shutdown_wait;
173
174 /* dlm tcp termination state */
175#define DLM_CLOSED 1
176#define DLM_ESTABLISHED 2
177#define DLM_FIN_WAIT1 3
178#define DLM_FIN_WAIT2 4
179#define DLM_CLOSE_WAIT 5
180#define DLM_LAST_ACK 6
181#define DLM_CLOSING 7
182 int state;
183 spinlock_t state_lock;
184
185 /* counts how many lockspaces are using this node
186 * this refcount is necessary to determine if the
187 * node wants to disconnect.
188 */
189 int users;
190
191 /* not protected by srcu, node_hash lifetime */
192 void *debugfs;
193
194 struct hlist_node hlist;
195 struct rcu_head rcu;
196};
197
198struct dlm_mhandle {
199 const union dlm_packet *inner_p;
200 struct midcomms_node *node;
201 struct dlm_opts *opts;
202 struct dlm_msg *msg;
203 bool committed;
204 uint32_t seq;
205
206 void (*ack_rcv)(struct midcomms_node *node);
207
208 /* get_mhandle/commit srcu idx exchange */
209 int idx;
210
211 struct list_head list;
212 struct rcu_head rcu;
213};
214
215static struct hlist_head node_hash[CONN_HASH_SIZE];
216static DEFINE_SPINLOCK(nodes_lock);
217DEFINE_STATIC_SRCU(nodes_srcu);
218
219/* This mutex prevents that midcomms_close() is running while
220 * stop() or remove(). As I experienced invalid memory access
221 * behaviours when DLM_DEBUG_FENCE_TERMINATION is enabled and
222 * resetting machines. I will end in some double deletion in nodes
223 * datastructure.
224 */
225static DEFINE_MUTEX(close_lock);
226
227struct kmem_cache *dlm_midcomms_cache_create(void)
228{
229 return KMEM_CACHE(dlm_mhandle, 0);
230}
231
232static inline const char *dlm_state_str(int state)
233{
234 switch (state) {
235 case DLM_CLOSED:
236 return "CLOSED";
237 case DLM_ESTABLISHED:
238 return "ESTABLISHED";
239 case DLM_FIN_WAIT1:
240 return "FIN_WAIT1";
241 case DLM_FIN_WAIT2:
242 return "FIN_WAIT2";
243 case DLM_CLOSE_WAIT:
244 return "CLOSE_WAIT";
245 case DLM_LAST_ACK:
246 return "LAST_ACK";
247 case DLM_CLOSING:
248 return "CLOSING";
249 default:
250 return "UNKNOWN";
251 }
252}
253
254const char *dlm_midcomms_state(struct midcomms_node *node)
255{
256 return dlm_state_str(state: node->state);
257}
258
259unsigned long dlm_midcomms_flags(struct midcomms_node *node)
260{
261 return node->flags;
262}
263
264int dlm_midcomms_send_queue_cnt(struct midcomms_node *node)
265{
266 return atomic_read(v: &node->send_queue_cnt);
267}
268
269uint32_t dlm_midcomms_version(struct midcomms_node *node)
270{
271 return node->version;
272}
273
274static struct midcomms_node *__find_node(int nodeid, int r)
275{
276 struct midcomms_node *node;
277
278 hlist_for_each_entry_rcu(node, &node_hash[r], hlist) {
279 if (node->nodeid == nodeid)
280 return node;
281 }
282
283 return NULL;
284}
285
286static void dlm_mhandle_release(struct rcu_head *rcu)
287{
288 struct dlm_mhandle *mh = container_of(rcu, struct dlm_mhandle, rcu);
289
290 dlm_lowcomms_put_msg(msg: mh->msg);
291 dlm_free_mhandle(mhandle: mh);
292}
293
294static void dlm_mhandle_delete(struct midcomms_node *node,
295 struct dlm_mhandle *mh)
296{
297 list_del_rcu(entry: &mh->list);
298 atomic_dec(v: &node->send_queue_cnt);
299 call_rcu(head: &mh->rcu, func: dlm_mhandle_release);
300}
301
302static void dlm_send_queue_flush(struct midcomms_node *node)
303{
304 struct dlm_mhandle *mh;
305
306 pr_debug("flush midcomms send queue of node %d\n", node->nodeid);
307
308 rcu_read_lock();
309 spin_lock_bh(lock: &node->send_queue_lock);
310 list_for_each_entry_rcu(mh, &node->send_queue, list) {
311 dlm_mhandle_delete(node, mh);
312 }
313 spin_unlock_bh(lock: &node->send_queue_lock);
314 rcu_read_unlock();
315}
316
317static void midcomms_node_reset(struct midcomms_node *node)
318{
319 pr_debug("reset node %d\n", node->nodeid);
320
321 atomic_set(v: &node->seq_next, DLM_SEQ_INIT);
322 atomic_set(v: &node->seq_send, DLM_SEQ_INIT);
323 atomic_set(v: &node->ulp_delivered, i: 0);
324 node->version = DLM_VERSION_NOT_SET;
325 node->flags = 0;
326
327 dlm_send_queue_flush(node);
328 node->state = DLM_CLOSED;
329 wake_up(&node->shutdown_wait);
330}
331
332static struct midcomms_node *nodeid2node(int nodeid)
333{
334 return __find_node(nodeid, r: nodeid_hash(nodeid));
335}
336
337int dlm_midcomms_addr(int nodeid, struct sockaddr_storage *addr)
338{
339 int ret, idx, r = nodeid_hash(nodeid);
340 struct midcomms_node *node;
341
342 ret = dlm_lowcomms_addr(nodeid, addr);
343 if (ret)
344 return ret;
345
346 idx = srcu_read_lock(ssp: &nodes_srcu);
347 node = __find_node(nodeid, r);
348 if (node) {
349 srcu_read_unlock(ssp: &nodes_srcu, idx);
350 return 0;
351 }
352 srcu_read_unlock(ssp: &nodes_srcu, idx);
353
354 node = kmalloc(sizeof(*node), GFP_NOFS);
355 if (!node)
356 return -ENOMEM;
357
358 node->nodeid = nodeid;
359 spin_lock_init(&node->state_lock);
360 spin_lock_init(&node->send_queue_lock);
361 atomic_set(v: &node->send_queue_cnt, i: 0);
362 INIT_LIST_HEAD(list: &node->send_queue);
363 init_waitqueue_head(&node->shutdown_wait);
364 node->users = 0;
365 midcomms_node_reset(node);
366
367 spin_lock_bh(lock: &nodes_lock);
368 hlist_add_head_rcu(n: &node->hlist, h: &node_hash[r]);
369 spin_unlock_bh(lock: &nodes_lock);
370
371 node->debugfs = dlm_create_debug_comms_file(nodeid, data: node);
372 return 0;
373}
374
375static int dlm_send_ack(int nodeid, uint32_t seq)
376{
377 int mb_len = sizeof(struct dlm_header);
378 struct dlm_header *m_header;
379 struct dlm_msg *msg;
380 char *ppc;
381
382 msg = dlm_lowcomms_new_msg(nodeid, len: mb_len, ppc: &ppc, NULL, NULL);
383 if (!msg)
384 return -ENOMEM;
385
386 m_header = (struct dlm_header *)ppc;
387
388 m_header->h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
389 m_header->h_nodeid = cpu_to_le32(dlm_our_nodeid());
390 m_header->h_length = cpu_to_le16(mb_len);
391 m_header->h_cmd = DLM_ACK;
392 m_header->u.h_seq = cpu_to_le32(seq);
393
394 dlm_lowcomms_commit_msg(msg);
395 dlm_lowcomms_put_msg(msg);
396
397 return 0;
398}
399
400static void dlm_send_ack_threshold(struct midcomms_node *node,
401 uint32_t threshold)
402{
403 uint32_t oval, nval;
404 bool send_ack;
405
406 /* let only send one user trigger threshold to send ack back */
407 do {
408 oval = atomic_read(v: &node->ulp_delivered);
409 send_ack = (oval > threshold);
410 /* abort if threshold is not reached */
411 if (!send_ack)
412 break;
413
414 nval = 0;
415 /* try to reset ulp_delivered counter */
416 } while (atomic_cmpxchg(v: &node->ulp_delivered, old: oval, new: nval) != oval);
417
418 if (send_ack)
419 dlm_send_ack(nodeid: node->nodeid, seq: atomic_read(v: &node->seq_next));
420}
421
422static int dlm_send_fin(struct midcomms_node *node,
423 void (*ack_rcv)(struct midcomms_node *node))
424{
425 int mb_len = sizeof(struct dlm_header);
426 struct dlm_header *m_header;
427 struct dlm_mhandle *mh;
428 char *ppc;
429
430 mh = dlm_midcomms_get_mhandle(nodeid: node->nodeid, len: mb_len, ppc: &ppc);
431 if (!mh)
432 return -ENOMEM;
433
434 set_bit(DLM_NODE_FLAG_STOP_TX, addr: &node->flags);
435 mh->ack_rcv = ack_rcv;
436
437 m_header = (struct dlm_header *)ppc;
438
439 m_header->h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
440 m_header->h_nodeid = cpu_to_le32(dlm_our_nodeid());
441 m_header->h_length = cpu_to_le16(mb_len);
442 m_header->h_cmd = DLM_FIN;
443
444 pr_debug("sending fin msg to node %d\n", node->nodeid);
445 dlm_midcomms_commit_mhandle(mh, NULL, namelen: 0);
446
447 return 0;
448}
449
450static void dlm_receive_ack(struct midcomms_node *node, uint32_t seq)
451{
452 struct dlm_mhandle *mh;
453
454 rcu_read_lock();
455 list_for_each_entry_rcu(mh, &node->send_queue, list) {
456 if (before(seq1: mh->seq, seq2: seq)) {
457 if (mh->ack_rcv)
458 mh->ack_rcv(node);
459 } else {
460 /* send queue should be ordered */
461 break;
462 }
463 }
464
465 spin_lock_bh(lock: &node->send_queue_lock);
466 list_for_each_entry_rcu(mh, &node->send_queue, list) {
467 if (before(seq1: mh->seq, seq2: seq)) {
468 dlm_mhandle_delete(node, mh);
469 } else {
470 /* send queue should be ordered */
471 break;
472 }
473 }
474 spin_unlock_bh(lock: &node->send_queue_lock);
475 rcu_read_unlock();
476}
477
478static void dlm_pas_fin_ack_rcv(struct midcomms_node *node)
479{
480 spin_lock_bh(lock: &node->state_lock);
481 pr_debug("receive passive fin ack from node %d with state %s\n",
482 node->nodeid, dlm_state_str(node->state));
483
484 switch (node->state) {
485 case DLM_LAST_ACK:
486 /* DLM_CLOSED */
487 midcomms_node_reset(node);
488 break;
489 case DLM_CLOSED:
490 /* not valid but somehow we got what we want */
491 wake_up(&node->shutdown_wait);
492 break;
493 default:
494 spin_unlock_bh(lock: &node->state_lock);
495 log_print("%s: unexpected state: %d",
496 __func__, node->state);
497 WARN_ON_ONCE(1);
498 return;
499 }
500 spin_unlock_bh(lock: &node->state_lock);
501}
502
503static void dlm_receive_buffer_3_2_trace(uint32_t seq,
504 const union dlm_packet *p)
505{
506 switch (p->header.h_cmd) {
507 case DLM_MSG:
508 trace_dlm_recv_message(dst: dlm_our_nodeid(), h_seq: seq, ms: &p->message);
509 break;
510 case DLM_RCOM:
511 trace_dlm_recv_rcom(dst: dlm_our_nodeid(), h_seq: seq, rc: &p->rcom);
512 break;
513 default:
514 break;
515 }
516}
517
518static void dlm_midcomms_receive_buffer(const union dlm_packet *p,
519 struct midcomms_node *node,
520 uint32_t seq)
521{
522 bool is_expected_seq;
523 uint32_t oval, nval;
524
525 do {
526 oval = atomic_read(v: &node->seq_next);
527 is_expected_seq = (oval == seq);
528 if (!is_expected_seq)
529 break;
530
531 nval = oval + 1;
532 } while (atomic_cmpxchg(v: &node->seq_next, old: oval, new: nval) != oval);
533
534 if (is_expected_seq) {
535 switch (p->header.h_cmd) {
536 case DLM_FIN:
537 spin_lock_bh(lock: &node->state_lock);
538 pr_debug("receive fin msg from node %d with state %s\n",
539 node->nodeid, dlm_state_str(node->state));
540
541 switch (node->state) {
542 case DLM_ESTABLISHED:
543 dlm_send_ack(nodeid: node->nodeid, seq: nval);
544
545 /* passive shutdown DLM_LAST_ACK case 1
546 * additional we check if the node is used by
547 * cluster manager events at all.
548 */
549 if (node->users == 0) {
550 node->state = DLM_LAST_ACK;
551 pr_debug("switch node %d to state %s case 1\n",
552 node->nodeid, dlm_state_str(node->state));
553 set_bit(DLM_NODE_FLAG_STOP_RX, addr: &node->flags);
554 dlm_send_fin(node, ack_rcv: dlm_pas_fin_ack_rcv);
555 } else {
556 node->state = DLM_CLOSE_WAIT;
557 pr_debug("switch node %d to state %s\n",
558 node->nodeid, dlm_state_str(node->state));
559 }
560 break;
561 case DLM_FIN_WAIT1:
562 dlm_send_ack(nodeid: node->nodeid, seq: nval);
563 node->state = DLM_CLOSING;
564 set_bit(DLM_NODE_FLAG_STOP_RX, addr: &node->flags);
565 pr_debug("switch node %d to state %s\n",
566 node->nodeid, dlm_state_str(node->state));
567 break;
568 case DLM_FIN_WAIT2:
569 dlm_send_ack(nodeid: node->nodeid, seq: nval);
570 midcomms_node_reset(node);
571 pr_debug("switch node %d to state %s\n",
572 node->nodeid, dlm_state_str(node->state));
573 break;
574 case DLM_LAST_ACK:
575 /* probably remove_member caught it, do nothing */
576 break;
577 default:
578 spin_unlock_bh(lock: &node->state_lock);
579 log_print("%s: unexpected state: %d",
580 __func__, node->state);
581 WARN_ON_ONCE(1);
582 return;
583 }
584 spin_unlock_bh(lock: &node->state_lock);
585 break;
586 default:
587 WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_RX, &node->flags));
588 dlm_receive_buffer_3_2_trace(seq, p);
589 dlm_receive_buffer(p, nodeid: node->nodeid);
590 atomic_inc(v: &node->ulp_delivered);
591 /* unlikely case to send ack back when we don't transmit */
592 dlm_send_ack_threshold(node, DLM_RECV_ACK_BACK_MSG_THRESHOLD);
593 break;
594 }
595 } else {
596 /* retry to ack message which we already have by sending back
597 * current node->seq_next number as ack.
598 */
599 if (seq < oval)
600 dlm_send_ack(nodeid: node->nodeid, seq: oval);
601
602 log_print_ratelimited("ignore dlm msg because seq mismatch, seq: %u, expected: %u, nodeid: %d",
603 seq, oval, node->nodeid);
604 }
605}
606
607static int dlm_opts_check_msglen(const union dlm_packet *p, uint16_t msglen,
608 int nodeid)
609{
610 int len = msglen;
611
612 /* we only trust outer header msglen because
613 * it's checked against receive buffer length.
614 */
615 if (len < sizeof(struct dlm_opts))
616 return -1;
617 len -= sizeof(struct dlm_opts);
618
619 if (len < le16_to_cpu(p->opts.o_optlen))
620 return -1;
621 len -= le16_to_cpu(p->opts.o_optlen);
622
623 switch (p->opts.o_nextcmd) {
624 case DLM_FIN:
625 if (len < sizeof(struct dlm_header)) {
626 log_print("fin too small: %d, will skip this message from node %d",
627 len, nodeid);
628 return -1;
629 }
630
631 break;
632 case DLM_MSG:
633 if (len < sizeof(struct dlm_message)) {
634 log_print("msg too small: %d, will skip this message from node %d",
635 msglen, nodeid);
636 return -1;
637 }
638
639 break;
640 case DLM_RCOM:
641 if (len < sizeof(struct dlm_rcom)) {
642 log_print("rcom msg too small: %d, will skip this message from node %d",
643 len, nodeid);
644 return -1;
645 }
646
647 break;
648 default:
649 log_print("unsupported o_nextcmd received: %u, will skip this message from node %d",
650 p->opts.o_nextcmd, nodeid);
651 return -1;
652 }
653
654 return 0;
655}
656
657static void dlm_midcomms_receive_buffer_3_2(const union dlm_packet *p, int nodeid)
658{
659 uint16_t msglen = le16_to_cpu(p->header.h_length);
660 struct midcomms_node *node;
661 uint32_t seq;
662 int ret, idx;
663
664 idx = srcu_read_lock(ssp: &nodes_srcu);
665 node = nodeid2node(nodeid);
666 if (WARN_ON_ONCE(!node))
667 goto out;
668
669 switch (node->version) {
670 case DLM_VERSION_NOT_SET:
671 node->version = DLM_VERSION_3_2;
672 wake_up(&node->shutdown_wait);
673 log_print("version 0x%08x for node %d detected", DLM_VERSION_3_2,
674 node->nodeid);
675
676 spin_lock(lock: &node->state_lock);
677 switch (node->state) {
678 case DLM_CLOSED:
679 node->state = DLM_ESTABLISHED;
680 pr_debug("switch node %d to state %s\n",
681 node->nodeid, dlm_state_str(node->state));
682 break;
683 default:
684 break;
685 }
686 spin_unlock(lock: &node->state_lock);
687
688 break;
689 case DLM_VERSION_3_2:
690 break;
691 default:
692 log_print_ratelimited("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
693 DLM_VERSION_3_2, node->nodeid, node->version);
694 goto out;
695 }
696
697 switch (p->header.h_cmd) {
698 case DLM_RCOM:
699 /* these rcom message we use to determine version.
700 * they have their own retransmission handling and
701 * are the first messages of dlm.
702 *
703 * length already checked.
704 */
705 switch (p->rcom.rc_type) {
706 case cpu_to_le32(DLM_RCOM_NAMES):
707 fallthrough;
708 case cpu_to_le32(DLM_RCOM_NAMES_REPLY):
709 fallthrough;
710 case cpu_to_le32(DLM_RCOM_STATUS):
711 fallthrough;
712 case cpu_to_le32(DLM_RCOM_STATUS_REPLY):
713 break;
714 default:
715 log_print("unsupported rcom type received: %u, will skip this message from node %d",
716 le32_to_cpu(p->rcom.rc_type), nodeid);
717 goto out;
718 }
719
720 WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_RX, &node->flags));
721 dlm_receive_buffer(p, nodeid);
722 break;
723 case DLM_OPTS:
724 seq = le32_to_cpu(p->header.u.h_seq);
725
726 ret = dlm_opts_check_msglen(p, msglen, nodeid);
727 if (ret < 0) {
728 log_print("opts msg too small: %u, will skip this message from node %d",
729 msglen, nodeid);
730 goto out;
731 }
732
733 p = (union dlm_packet *)((unsigned char *)p->opts.o_opts +
734 le16_to_cpu(p->opts.o_optlen));
735
736 /* recheck inner msglen just if it's not garbage */
737 msglen = le16_to_cpu(p->header.h_length);
738 switch (p->header.h_cmd) {
739 case DLM_RCOM:
740 if (msglen < sizeof(struct dlm_rcom)) {
741 log_print("inner rcom msg too small: %u, will skip this message from node %d",
742 msglen, nodeid);
743 goto out;
744 }
745
746 break;
747 case DLM_MSG:
748 if (msglen < sizeof(struct dlm_message)) {
749 log_print("inner msg too small: %u, will skip this message from node %d",
750 msglen, nodeid);
751 goto out;
752 }
753
754 break;
755 case DLM_FIN:
756 if (msglen < sizeof(struct dlm_header)) {
757 log_print("inner fin too small: %u, will skip this message from node %d",
758 msglen, nodeid);
759 goto out;
760 }
761
762 break;
763 default:
764 log_print("unsupported inner h_cmd received: %u, will skip this message from node %d",
765 msglen, nodeid);
766 goto out;
767 }
768
769 dlm_midcomms_receive_buffer(p, node, seq);
770 break;
771 case DLM_ACK:
772 seq = le32_to_cpu(p->header.u.h_seq);
773 dlm_receive_ack(node, seq);
774 break;
775 default:
776 log_print("unsupported h_cmd received: %u, will skip this message from node %d",
777 p->header.h_cmd, nodeid);
778 break;
779 }
780
781out:
782 srcu_read_unlock(ssp: &nodes_srcu, idx);
783}
784
785static void dlm_midcomms_receive_buffer_3_1(const union dlm_packet *p, int nodeid)
786{
787 uint16_t msglen = le16_to_cpu(p->header.h_length);
788 struct midcomms_node *node;
789 int idx;
790
791 idx = srcu_read_lock(ssp: &nodes_srcu);
792 node = nodeid2node(nodeid);
793 if (WARN_ON_ONCE(!node)) {
794 srcu_read_unlock(ssp: &nodes_srcu, idx);
795 return;
796 }
797
798 switch (node->version) {
799 case DLM_VERSION_NOT_SET:
800 node->version = DLM_VERSION_3_1;
801 wake_up(&node->shutdown_wait);
802 log_print("version 0x%08x for node %d detected", DLM_VERSION_3_1,
803 node->nodeid);
804 break;
805 case DLM_VERSION_3_1:
806 break;
807 default:
808 log_print_ratelimited("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
809 DLM_VERSION_3_1, node->nodeid, node->version);
810 srcu_read_unlock(ssp: &nodes_srcu, idx);
811 return;
812 }
813 srcu_read_unlock(ssp: &nodes_srcu, idx);
814
815 switch (p->header.h_cmd) {
816 case DLM_RCOM:
817 /* length already checked */
818 break;
819 case DLM_MSG:
820 if (msglen < sizeof(struct dlm_message)) {
821 log_print("msg too small: %u, will skip this message from node %d",
822 msglen, nodeid);
823 return;
824 }
825
826 break;
827 default:
828 log_print("unsupported h_cmd received: %u, will skip this message from node %d",
829 p->header.h_cmd, nodeid);
830 return;
831 }
832
833 dlm_receive_buffer(p, nodeid);
834}
835
836int dlm_validate_incoming_buffer(int nodeid, unsigned char *buf, int len)
837{
838 const unsigned char *ptr = buf;
839 const struct dlm_header *hd;
840 uint16_t msglen;
841 int ret = 0;
842
843 while (len >= sizeof(struct dlm_header)) {
844 hd = (struct dlm_header *)ptr;
845
846 /* no message should be more than DLM_MAX_SOCKET_BUFSIZE or
847 * less than dlm_header size.
848 *
849 * Some messages does not have a 8 byte length boundary yet
850 * which can occur in a unaligned memory access of some dlm
851 * messages. However this problem need to be fixed at the
852 * sending side, for now it seems nobody run into architecture
853 * related issues yet but it slows down some processing.
854 * Fixing this issue should be scheduled in future by doing
855 * the next major version bump.
856 */
857 msglen = le16_to_cpu(hd->h_length);
858 if (msglen > DLM_MAX_SOCKET_BUFSIZE ||
859 msglen < sizeof(struct dlm_header)) {
860 log_print("received invalid length header: %u from node %d, will abort message parsing",
861 msglen, nodeid);
862 return -EBADMSG;
863 }
864
865 /* caller will take care that leftover
866 * will be parsed next call with more data
867 */
868 if (msglen > len)
869 break;
870
871 ret += msglen;
872 len -= msglen;
873 ptr += msglen;
874 }
875
876 return ret;
877}
878
879/*
880 * Called from the low-level comms layer to process a buffer of
881 * commands.
882 */
883int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int len)
884{
885 const unsigned char *ptr = buf;
886 const struct dlm_header *hd;
887 uint16_t msglen;
888 int ret = 0;
889
890 while (len >= sizeof(struct dlm_header)) {
891 hd = (struct dlm_header *)ptr;
892
893 msglen = le16_to_cpu(hd->h_length);
894 if (msglen > len)
895 break;
896
897 switch (hd->h_version) {
898 case cpu_to_le32(DLM_VERSION_3_1):
899 dlm_midcomms_receive_buffer_3_1(p: (const union dlm_packet *)ptr, nodeid);
900 break;
901 case cpu_to_le32(DLM_VERSION_3_2):
902 dlm_midcomms_receive_buffer_3_2(p: (const union dlm_packet *)ptr, nodeid);
903 break;
904 default:
905 log_print("received invalid version header: %u from node %d, will skip this message",
906 le32_to_cpu(hd->h_version), nodeid);
907 break;
908 }
909
910 ret += msglen;
911 len -= msglen;
912 ptr += msglen;
913 }
914
915 return ret;
916}
917
918void dlm_midcomms_unack_msg_resend(int nodeid)
919{
920 struct midcomms_node *node;
921 struct dlm_mhandle *mh;
922 int idx, ret;
923
924 idx = srcu_read_lock(ssp: &nodes_srcu);
925 node = nodeid2node(nodeid);
926 if (WARN_ON_ONCE(!node)) {
927 srcu_read_unlock(ssp: &nodes_srcu, idx);
928 return;
929 }
930
931 /* old protocol, we don't support to retransmit on failure */
932 switch (node->version) {
933 case DLM_VERSION_3_2:
934 break;
935 default:
936 srcu_read_unlock(ssp: &nodes_srcu, idx);
937 return;
938 }
939
940 rcu_read_lock();
941 list_for_each_entry_rcu(mh, &node->send_queue, list) {
942 if (!mh->committed)
943 continue;
944
945 ret = dlm_lowcomms_resend_msg(msg: mh->msg);
946 if (!ret)
947 log_print_ratelimited("retransmit dlm msg, seq %u, nodeid %d",
948 mh->seq, node->nodeid);
949 }
950 rcu_read_unlock();
951 srcu_read_unlock(ssp: &nodes_srcu, idx);
952}
953
954static void dlm_fill_opts_header(struct dlm_opts *opts, uint16_t inner_len,
955 uint32_t seq)
956{
957 opts->o_header.h_cmd = DLM_OPTS;
958 opts->o_header.h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
959 opts->o_header.h_nodeid = cpu_to_le32(dlm_our_nodeid());
960 opts->o_header.h_length = cpu_to_le16(DLM_MIDCOMMS_OPT_LEN + inner_len);
961 opts->o_header.u.h_seq = cpu_to_le32(seq);
962}
963
964static void midcomms_new_msg_cb(void *data)
965{
966 struct dlm_mhandle *mh = data;
967
968 atomic_inc(v: &mh->node->send_queue_cnt);
969
970 spin_lock_bh(lock: &mh->node->send_queue_lock);
971 list_add_tail_rcu(new: &mh->list, head: &mh->node->send_queue);
972 spin_unlock_bh(lock: &mh->node->send_queue_lock);
973
974 mh->seq = atomic_fetch_inc(v: &mh->node->seq_send);
975}
976
977static struct dlm_msg *dlm_midcomms_get_msg_3_2(struct dlm_mhandle *mh, int nodeid,
978 int len, char **ppc)
979{
980 struct dlm_opts *opts;
981 struct dlm_msg *msg;
982
983 msg = dlm_lowcomms_new_msg(nodeid, len: len + DLM_MIDCOMMS_OPT_LEN,
984 ppc, cb: midcomms_new_msg_cb, data: mh);
985 if (!msg)
986 return NULL;
987
988 opts = (struct dlm_opts *)*ppc;
989 mh->opts = opts;
990
991 /* add possible options here */
992 dlm_fill_opts_header(opts, inner_len: len, seq: mh->seq);
993
994 *ppc += sizeof(*opts);
995 mh->inner_p = (const union dlm_packet *)*ppc;
996 return msg;
997}
998
999/* avoid false positive for nodes_srcu, unlock happens in
1000 * dlm_midcomms_commit_mhandle which is a must call if success
1001 */
1002#ifndef __CHECKER__
1003struct dlm_mhandle *dlm_midcomms_get_mhandle(int nodeid, int len, char **ppc)
1004{
1005 struct midcomms_node *node;
1006 struct dlm_mhandle *mh;
1007 struct dlm_msg *msg;
1008 int idx;
1009
1010 idx = srcu_read_lock(ssp: &nodes_srcu);
1011 node = nodeid2node(nodeid);
1012 if (WARN_ON_ONCE(!node))
1013 goto err;
1014
1015 /* this is a bug, however we going on and hope it will be resolved */
1016 WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_TX, &node->flags));
1017
1018 mh = dlm_allocate_mhandle();
1019 if (!mh)
1020 goto err;
1021
1022 mh->committed = false;
1023 mh->ack_rcv = NULL;
1024 mh->idx = idx;
1025 mh->node = node;
1026
1027 switch (node->version) {
1028 case DLM_VERSION_3_1:
1029 msg = dlm_lowcomms_new_msg(nodeid, len, ppc, NULL, NULL);
1030 if (!msg) {
1031 dlm_free_mhandle(mhandle: mh);
1032 goto err;
1033 }
1034
1035 break;
1036 case DLM_VERSION_3_2:
1037 /* send ack back if necessary */
1038 dlm_send_ack_threshold(node, DLM_SEND_ACK_BACK_MSG_THRESHOLD);
1039
1040 msg = dlm_midcomms_get_msg_3_2(mh, nodeid, len, ppc);
1041 if (!msg) {
1042 dlm_free_mhandle(mhandle: mh);
1043 goto err;
1044 }
1045 break;
1046 default:
1047 dlm_free_mhandle(mhandle: mh);
1048 WARN_ON_ONCE(1);
1049 goto err;
1050 }
1051
1052 mh->msg = msg;
1053
1054 /* keep in mind that is a must to call
1055 * dlm_midcomms_commit_msg() which releases
1056 * nodes_srcu using mh->idx which is assumed
1057 * here that the application will call it.
1058 */
1059 return mh;
1060
1061err:
1062 srcu_read_unlock(ssp: &nodes_srcu, idx);
1063 return NULL;
1064}
1065#endif
1066
1067static void dlm_midcomms_commit_msg_3_2_trace(const struct dlm_mhandle *mh,
1068 const void *name, int namelen)
1069{
1070 switch (mh->inner_p->header.h_cmd) {
1071 case DLM_MSG:
1072 trace_dlm_send_message(dst: mh->node->nodeid, h_seq: mh->seq,
1073 ms: &mh->inner_p->message,
1074 name, namelen);
1075 break;
1076 case DLM_RCOM:
1077 trace_dlm_send_rcom(dst: mh->node->nodeid, h_seq: mh->seq,
1078 rc: &mh->inner_p->rcom);
1079 break;
1080 default:
1081 /* nothing to trace */
1082 break;
1083 }
1084}
1085
1086static void dlm_midcomms_commit_msg_3_2(struct dlm_mhandle *mh,
1087 const void *name, int namelen)
1088{
1089 /* nexthdr chain for fast lookup */
1090 mh->opts->o_nextcmd = mh->inner_p->header.h_cmd;
1091 mh->committed = true;
1092 dlm_midcomms_commit_msg_3_2_trace(mh, name, namelen);
1093 dlm_lowcomms_commit_msg(msg: mh->msg);
1094}
1095
1096/* avoid false positive for nodes_srcu, lock was happen in
1097 * dlm_midcomms_get_mhandle
1098 */
1099#ifndef __CHECKER__
1100void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh,
1101 const void *name, int namelen)
1102{
1103
1104 switch (mh->node->version) {
1105 case DLM_VERSION_3_1:
1106 srcu_read_unlock(ssp: &nodes_srcu, idx: mh->idx);
1107
1108 dlm_lowcomms_commit_msg(msg: mh->msg);
1109 dlm_lowcomms_put_msg(msg: mh->msg);
1110 /* mh is not part of rcu list in this case */
1111 dlm_free_mhandle(mhandle: mh);
1112 break;
1113 case DLM_VERSION_3_2:
1114 /* held rcu read lock here, because we sending the
1115 * dlm message out, when we do that we could receive
1116 * an ack back which releases the mhandle and we
1117 * get a use after free.
1118 */
1119 rcu_read_lock();
1120 dlm_midcomms_commit_msg_3_2(mh, name, namelen);
1121 srcu_read_unlock(ssp: &nodes_srcu, idx: mh->idx);
1122 rcu_read_unlock();
1123 break;
1124 default:
1125 srcu_read_unlock(ssp: &nodes_srcu, idx: mh->idx);
1126 WARN_ON_ONCE(1);
1127 break;
1128 }
1129}
1130#endif
1131
1132int dlm_midcomms_start(void)
1133{
1134 return dlm_lowcomms_start();
1135}
1136
1137void dlm_midcomms_stop(void)
1138{
1139 dlm_lowcomms_stop();
1140}
1141
1142void dlm_midcomms_init(void)
1143{
1144 int i;
1145
1146 for (i = 0; i < CONN_HASH_SIZE; i++)
1147 INIT_HLIST_HEAD(&node_hash[i]);
1148
1149 dlm_lowcomms_init();
1150}
1151
1152static void midcomms_node_release(struct rcu_head *rcu)
1153{
1154 struct midcomms_node *node = container_of(rcu, struct midcomms_node, rcu);
1155
1156 WARN_ON_ONCE(atomic_read(&node->send_queue_cnt));
1157 dlm_send_queue_flush(node);
1158 kfree(objp: node);
1159}
1160
1161void dlm_midcomms_exit(void)
1162{
1163 struct midcomms_node *node;
1164 int i, idx;
1165
1166 idx = srcu_read_lock(ssp: &nodes_srcu);
1167 for (i = 0; i < CONN_HASH_SIZE; i++) {
1168 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1169 dlm_delete_debug_comms_file(ctx: node->debugfs);
1170
1171 spin_lock(lock: &nodes_lock);
1172 hlist_del_rcu(n: &node->hlist);
1173 spin_unlock(lock: &nodes_lock);
1174
1175 call_srcu(ssp: &nodes_srcu, head: &node->rcu, func: midcomms_node_release);
1176 }
1177 }
1178 srcu_read_unlock(ssp: &nodes_srcu, idx);
1179
1180 dlm_lowcomms_exit();
1181}
1182
1183static void dlm_act_fin_ack_rcv(struct midcomms_node *node)
1184{
1185 spin_lock_bh(lock: &node->state_lock);
1186 pr_debug("receive active fin ack from node %d with state %s\n",
1187 node->nodeid, dlm_state_str(node->state));
1188
1189 switch (node->state) {
1190 case DLM_FIN_WAIT1:
1191 node->state = DLM_FIN_WAIT2;
1192 pr_debug("switch node %d to state %s\n",
1193 node->nodeid, dlm_state_str(node->state));
1194 break;
1195 case DLM_CLOSING:
1196 midcomms_node_reset(node);
1197 pr_debug("switch node %d to state %s\n",
1198 node->nodeid, dlm_state_str(node->state));
1199 break;
1200 case DLM_CLOSED:
1201 /* not valid but somehow we got what we want */
1202 wake_up(&node->shutdown_wait);
1203 break;
1204 default:
1205 spin_unlock_bh(lock: &node->state_lock);
1206 log_print("%s: unexpected state: %d",
1207 __func__, node->state);
1208 WARN_ON_ONCE(1);
1209 return;
1210 }
1211 spin_unlock_bh(lock: &node->state_lock);
1212}
1213
1214void dlm_midcomms_add_member(int nodeid)
1215{
1216 struct midcomms_node *node;
1217 int idx;
1218
1219 idx = srcu_read_lock(ssp: &nodes_srcu);
1220 node = nodeid2node(nodeid);
1221 if (WARN_ON_ONCE(!node)) {
1222 srcu_read_unlock(ssp: &nodes_srcu, idx);
1223 return;
1224 }
1225
1226 spin_lock_bh(lock: &node->state_lock);
1227 if (!node->users) {
1228 pr_debug("receive add member from node %d with state %s\n",
1229 node->nodeid, dlm_state_str(node->state));
1230 switch (node->state) {
1231 case DLM_ESTABLISHED:
1232 break;
1233 case DLM_CLOSED:
1234 node->state = DLM_ESTABLISHED;
1235 pr_debug("switch node %d to state %s\n",
1236 node->nodeid, dlm_state_str(node->state));
1237 break;
1238 default:
1239 /* some invalid state passive shutdown
1240 * was failed, we try to reset and
1241 * hope it will go on.
1242 */
1243 log_print("reset node %d because shutdown stuck",
1244 node->nodeid);
1245
1246 midcomms_node_reset(node);
1247 node->state = DLM_ESTABLISHED;
1248 break;
1249 }
1250 }
1251
1252 node->users++;
1253 pr_debug("node %d users inc count %d\n", nodeid, node->users);
1254 spin_unlock_bh(lock: &node->state_lock);
1255
1256 srcu_read_unlock(ssp: &nodes_srcu, idx);
1257}
1258
1259void dlm_midcomms_remove_member(int nodeid)
1260{
1261 struct midcomms_node *node;
1262 int idx;
1263
1264 idx = srcu_read_lock(ssp: &nodes_srcu);
1265 node = nodeid2node(nodeid);
1266 /* in case of dlm_midcomms_close() removes node */
1267 if (!node) {
1268 srcu_read_unlock(ssp: &nodes_srcu, idx);
1269 return;
1270 }
1271
1272 spin_lock_bh(lock: &node->state_lock);
1273 /* case of dlm_midcomms_addr() created node but
1274 * was not added before because dlm_midcomms_close()
1275 * removed the node
1276 */
1277 if (!node->users) {
1278 spin_unlock_bh(lock: &node->state_lock);
1279 srcu_read_unlock(ssp: &nodes_srcu, idx);
1280 return;
1281 }
1282
1283 node->users--;
1284 pr_debug("node %d users dec count %d\n", nodeid, node->users);
1285
1286 /* hitting users count to zero means the
1287 * other side is running dlm_midcomms_stop()
1288 * we meet us to have a clean disconnect.
1289 */
1290 if (node->users == 0) {
1291 pr_debug("receive remove member from node %d with state %s\n",
1292 node->nodeid, dlm_state_str(node->state));
1293 switch (node->state) {
1294 case DLM_ESTABLISHED:
1295 break;
1296 case DLM_CLOSE_WAIT:
1297 /* passive shutdown DLM_LAST_ACK case 2 */
1298 node->state = DLM_LAST_ACK;
1299 pr_debug("switch node %d to state %s case 2\n",
1300 node->nodeid, dlm_state_str(node->state));
1301 set_bit(DLM_NODE_FLAG_STOP_RX, addr: &node->flags);
1302 dlm_send_fin(node, ack_rcv: dlm_pas_fin_ack_rcv);
1303 break;
1304 case DLM_LAST_ACK:
1305 /* probably receive fin caught it, do nothing */
1306 break;
1307 case DLM_CLOSED:
1308 /* already gone, do nothing */
1309 break;
1310 default:
1311 log_print("%s: unexpected state: %d",
1312 __func__, node->state);
1313 break;
1314 }
1315 }
1316 spin_unlock_bh(lock: &node->state_lock);
1317
1318 srcu_read_unlock(ssp: &nodes_srcu, idx);
1319}
1320
1321void dlm_midcomms_version_wait(void)
1322{
1323 struct midcomms_node *node;
1324 int i, idx, ret;
1325
1326 idx = srcu_read_lock(ssp: &nodes_srcu);
1327 for (i = 0; i < CONN_HASH_SIZE; i++) {
1328 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1329 ret = wait_event_timeout(node->shutdown_wait,
1330 node->version != DLM_VERSION_NOT_SET ||
1331 node->state == DLM_CLOSED ||
1332 test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
1333 DLM_SHUTDOWN_TIMEOUT);
1334 if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags))
1335 pr_debug("version wait timed out for node %d with state %s\n",
1336 node->nodeid, dlm_state_str(node->state));
1337 }
1338 }
1339 srcu_read_unlock(ssp: &nodes_srcu, idx);
1340}
1341
1342static void midcomms_shutdown(struct midcomms_node *node)
1343{
1344 int ret;
1345
1346 /* old protocol, we don't wait for pending operations */
1347 switch (node->version) {
1348 case DLM_VERSION_3_2:
1349 break;
1350 default:
1351 return;
1352 }
1353
1354 spin_lock_bh(lock: &node->state_lock);
1355 pr_debug("receive active shutdown for node %d with state %s\n",
1356 node->nodeid, dlm_state_str(node->state));
1357 switch (node->state) {
1358 case DLM_ESTABLISHED:
1359 node->state = DLM_FIN_WAIT1;
1360 pr_debug("switch node %d to state %s case 2\n",
1361 node->nodeid, dlm_state_str(node->state));
1362 dlm_send_fin(node, ack_rcv: dlm_act_fin_ack_rcv);
1363 break;
1364 case DLM_CLOSED:
1365 /* we have what we want */
1366 break;
1367 default:
1368 /* busy to enter DLM_FIN_WAIT1, wait until passive
1369 * done in shutdown_wait to enter DLM_CLOSED.
1370 */
1371 break;
1372 }
1373 spin_unlock_bh(lock: &node->state_lock);
1374
1375 if (DLM_DEBUG_FENCE_TERMINATION)
1376 msleep(msecs: 5000);
1377
1378 /* wait for other side dlm + fin */
1379 ret = wait_event_timeout(node->shutdown_wait,
1380 node->state == DLM_CLOSED ||
1381 test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
1382 DLM_SHUTDOWN_TIMEOUT);
1383 if (!ret)
1384 pr_debug("active shutdown timed out for node %d with state %s\n",
1385 node->nodeid, dlm_state_str(node->state));
1386 else
1387 pr_debug("active shutdown done for node %d with state %s\n",
1388 node->nodeid, dlm_state_str(node->state));
1389}
1390
1391void dlm_midcomms_shutdown(void)
1392{
1393 struct midcomms_node *node;
1394 int i, idx;
1395
1396 mutex_lock(&close_lock);
1397 idx = srcu_read_lock(ssp: &nodes_srcu);
1398 for (i = 0; i < CONN_HASH_SIZE; i++) {
1399 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1400 midcomms_shutdown(node);
1401 }
1402 }
1403
1404 dlm_lowcomms_shutdown();
1405
1406 for (i = 0; i < CONN_HASH_SIZE; i++) {
1407 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1408 midcomms_node_reset(node);
1409 }
1410 }
1411 srcu_read_unlock(ssp: &nodes_srcu, idx);
1412 mutex_unlock(lock: &close_lock);
1413}
1414
1415int dlm_midcomms_close(int nodeid)
1416{
1417 struct midcomms_node *node;
1418 int idx, ret;
1419
1420 idx = srcu_read_lock(ssp: &nodes_srcu);
1421 /* Abort pending close/remove operation */
1422 node = nodeid2node(nodeid);
1423 if (node) {
1424 /* let shutdown waiters leave */
1425 set_bit(DLM_NODE_FLAG_CLOSE, addr: &node->flags);
1426 wake_up(&node->shutdown_wait);
1427 }
1428 srcu_read_unlock(ssp: &nodes_srcu, idx);
1429
1430 synchronize_srcu(ssp: &nodes_srcu);
1431
1432 mutex_lock(&close_lock);
1433 idx = srcu_read_lock(ssp: &nodes_srcu);
1434 node = nodeid2node(nodeid);
1435 if (!node) {
1436 srcu_read_unlock(ssp: &nodes_srcu, idx);
1437 mutex_unlock(lock: &close_lock);
1438 return dlm_lowcomms_close(nodeid);
1439 }
1440
1441 ret = dlm_lowcomms_close(nodeid);
1442 dlm_delete_debug_comms_file(ctx: node->debugfs);
1443
1444 spin_lock_bh(lock: &nodes_lock);
1445 hlist_del_rcu(n: &node->hlist);
1446 spin_unlock_bh(lock: &nodes_lock);
1447 srcu_read_unlock(ssp: &nodes_srcu, idx);
1448
1449 /* wait that all readers left until flush send queue */
1450 synchronize_srcu(ssp: &nodes_srcu);
1451
1452 /* drop all pending dlm messages, this is fine as
1453 * this function get called when the node is fenced
1454 */
1455 dlm_send_queue_flush(node);
1456
1457 call_srcu(ssp: &nodes_srcu, head: &node->rcu, func: midcomms_node_release);
1458 mutex_unlock(lock: &close_lock);
1459
1460 return ret;
1461}
1462
1463/* debug functionality to send raw dlm msg from user space */
1464struct dlm_rawmsg_data {
1465 struct midcomms_node *node;
1466 void *buf;
1467};
1468
1469static void midcomms_new_rawmsg_cb(void *data)
1470{
1471 struct dlm_rawmsg_data *rd = data;
1472 struct dlm_header *h = rd->buf;
1473
1474 switch (h->h_version) {
1475 case cpu_to_le32(DLM_VERSION_3_1):
1476 break;
1477 default:
1478 switch (h->h_cmd) {
1479 case DLM_OPTS:
1480 if (!h->u.h_seq)
1481 h->u.h_seq = cpu_to_le32(atomic_fetch_inc(&rd->node->seq_send));
1482 break;
1483 default:
1484 break;
1485 }
1486 break;
1487 }
1488}
1489
1490int dlm_midcomms_rawmsg_send(struct midcomms_node *node, void *buf,
1491 int buflen)
1492{
1493 struct dlm_rawmsg_data rd;
1494 struct dlm_msg *msg;
1495 char *msgbuf;
1496
1497 rd.node = node;
1498 rd.buf = buf;
1499
1500 msg = dlm_lowcomms_new_msg(nodeid: node->nodeid, len: buflen, ppc: &msgbuf,
1501 cb: midcomms_new_rawmsg_cb, data: &rd);
1502 if (!msg)
1503 return -ENOMEM;
1504
1505 memcpy(msgbuf, buf, buflen);
1506 dlm_lowcomms_commit_msg(msg);
1507 return 0;
1508}
1509
1510

source code of linux/fs/dlm/midcomms.c