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_create(name: "dlm_mhandle", size: sizeof(struct dlm_mhandle),
230 align: 0, flags: 0, NULL);
231}
232
233static inline const char *dlm_state_str(int state)
234{
235 switch (state) {
236 case DLM_CLOSED:
237 return "CLOSED";
238 case DLM_ESTABLISHED:
239 return "ESTABLISHED";
240 case DLM_FIN_WAIT1:
241 return "FIN_WAIT1";
242 case DLM_FIN_WAIT2:
243 return "FIN_WAIT2";
244 case DLM_CLOSE_WAIT:
245 return "CLOSE_WAIT";
246 case DLM_LAST_ACK:
247 return "LAST_ACK";
248 case DLM_CLOSING:
249 return "CLOSING";
250 default:
251 return "UNKNOWN";
252 }
253}
254
255const char *dlm_midcomms_state(struct midcomms_node *node)
256{
257 return dlm_state_str(state: node->state);
258}
259
260unsigned long dlm_midcomms_flags(struct midcomms_node *node)
261{
262 return node->flags;
263}
264
265int dlm_midcomms_send_queue_cnt(struct midcomms_node *node)
266{
267 return atomic_read(v: &node->send_queue_cnt);
268}
269
270uint32_t dlm_midcomms_version(struct midcomms_node *node)
271{
272 return node->version;
273}
274
275static struct midcomms_node *__find_node(int nodeid, int r)
276{
277 struct midcomms_node *node;
278
279 hlist_for_each_entry_rcu(node, &node_hash[r], hlist) {
280 if (node->nodeid == nodeid)
281 return node;
282 }
283
284 return NULL;
285}
286
287static void dlm_mhandle_release(struct rcu_head *rcu)
288{
289 struct dlm_mhandle *mh = container_of(rcu, struct dlm_mhandle, rcu);
290
291 dlm_lowcomms_put_msg(msg: mh->msg);
292 dlm_free_mhandle(mhandle: mh);
293}
294
295static void dlm_mhandle_delete(struct midcomms_node *node,
296 struct dlm_mhandle *mh)
297{
298 list_del_rcu(entry: &mh->list);
299 atomic_dec(v: &node->send_queue_cnt);
300 call_rcu(head: &mh->rcu, func: dlm_mhandle_release);
301}
302
303static void dlm_send_queue_flush(struct midcomms_node *node)
304{
305 struct dlm_mhandle *mh;
306
307 pr_debug("flush midcomms send queue of node %d\n", node->nodeid);
308
309 rcu_read_lock();
310 spin_lock_bh(lock: &node->send_queue_lock);
311 list_for_each_entry_rcu(mh, &node->send_queue, list) {
312 dlm_mhandle_delete(node, mh);
313 }
314 spin_unlock_bh(lock: &node->send_queue_lock);
315 rcu_read_unlock();
316}
317
318static void midcomms_node_reset(struct midcomms_node *node)
319{
320 pr_debug("reset node %d\n", node->nodeid);
321
322 atomic_set(v: &node->seq_next, DLM_SEQ_INIT);
323 atomic_set(v: &node->seq_send, DLM_SEQ_INIT);
324 atomic_set(v: &node->ulp_delivered, i: 0);
325 node->version = DLM_VERSION_NOT_SET;
326 node->flags = 0;
327
328 dlm_send_queue_flush(node);
329 node->state = DLM_CLOSED;
330 wake_up(&node->shutdown_wait);
331}
332
333static struct midcomms_node *nodeid2node(int nodeid)
334{
335 return __find_node(nodeid, r: nodeid_hash(nodeid));
336}
337
338int dlm_midcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
339{
340 int ret, idx, r = nodeid_hash(nodeid);
341 struct midcomms_node *node;
342
343 ret = dlm_lowcomms_addr(nodeid, addr, len);
344 if (ret)
345 return ret;
346
347 idx = srcu_read_lock(ssp: &nodes_srcu);
348 node = __find_node(nodeid, r);
349 if (node) {
350 srcu_read_unlock(ssp: &nodes_srcu, idx);
351 return 0;
352 }
353 srcu_read_unlock(ssp: &nodes_srcu, idx);
354
355 node = kmalloc(size: sizeof(*node), GFP_NOFS);
356 if (!node)
357 return -ENOMEM;
358
359 node->nodeid = nodeid;
360 spin_lock_init(&node->state_lock);
361 spin_lock_init(&node->send_queue_lock);
362 atomic_set(v: &node->send_queue_cnt, i: 0);
363 INIT_LIST_HEAD(list: &node->send_queue);
364 init_waitqueue_head(&node->shutdown_wait);
365 node->users = 0;
366 midcomms_node_reset(node);
367
368 spin_lock(lock: &nodes_lock);
369 hlist_add_head_rcu(n: &node->hlist, h: &node_hash[r]);
370 spin_unlock(lock: &nodes_lock);
371
372 node->debugfs = dlm_create_debug_comms_file(nodeid, data: node);
373 return 0;
374}
375
376static int dlm_send_ack(int nodeid, uint32_t seq)
377{
378 int mb_len = sizeof(struct dlm_header);
379 struct dlm_header *m_header;
380 struct dlm_msg *msg;
381 char *ppc;
382
383 msg = dlm_lowcomms_new_msg(nodeid, len: mb_len, GFP_ATOMIC, ppc: &ppc,
384 NULL, NULL);
385 if (!msg)
386 return -ENOMEM;
387
388 m_header = (struct dlm_header *)ppc;
389
390 m_header->h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
391 m_header->h_nodeid = cpu_to_le32(dlm_our_nodeid());
392 m_header->h_length = cpu_to_le16(mb_len);
393 m_header->h_cmd = DLM_ACK;
394 m_header->u.h_seq = cpu_to_le32(seq);
395
396 dlm_lowcomms_commit_msg(msg);
397 dlm_lowcomms_put_msg(msg);
398
399 return 0;
400}
401
402static void dlm_send_ack_threshold(struct midcomms_node *node,
403 uint32_t threshold)
404{
405 uint32_t oval, nval;
406 bool send_ack;
407
408 /* let only send one user trigger threshold to send ack back */
409 do {
410 oval = atomic_read(v: &node->ulp_delivered);
411 send_ack = (oval > threshold);
412 /* abort if threshold is not reached */
413 if (!send_ack)
414 break;
415
416 nval = 0;
417 /* try to reset ulp_delivered counter */
418 } while (atomic_cmpxchg(v: &node->ulp_delivered, old: oval, new: nval) != oval);
419
420 if (send_ack)
421 dlm_send_ack(nodeid: node->nodeid, seq: atomic_read(v: &node->seq_next));
422}
423
424static int dlm_send_fin(struct midcomms_node *node,
425 void (*ack_rcv)(struct midcomms_node *node))
426{
427 int mb_len = sizeof(struct dlm_header);
428 struct dlm_header *m_header;
429 struct dlm_mhandle *mh;
430 char *ppc;
431
432 mh = dlm_midcomms_get_mhandle(nodeid: node->nodeid, len: mb_len, GFP_ATOMIC, ppc: &ppc);
433 if (!mh)
434 return -ENOMEM;
435
436 set_bit(DLM_NODE_FLAG_STOP_TX, addr: &node->flags);
437 mh->ack_rcv = ack_rcv;
438
439 m_header = (struct dlm_header *)ppc;
440
441 m_header->h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
442 m_header->h_nodeid = cpu_to_le32(dlm_our_nodeid());
443 m_header->h_length = cpu_to_le16(mb_len);
444 m_header->h_cmd = DLM_FIN;
445
446 pr_debug("sending fin msg to node %d\n", node->nodeid);
447 dlm_midcomms_commit_mhandle(mh, NULL, namelen: 0);
448
449 return 0;
450}
451
452static void dlm_receive_ack(struct midcomms_node *node, uint32_t seq)
453{
454 struct dlm_mhandle *mh;
455
456 rcu_read_lock();
457 list_for_each_entry_rcu(mh, &node->send_queue, list) {
458 if (before(seq1: mh->seq, seq2: seq)) {
459 if (mh->ack_rcv)
460 mh->ack_rcv(node);
461 } else {
462 /* send queue should be ordered */
463 break;
464 }
465 }
466
467 spin_lock_bh(lock: &node->send_queue_lock);
468 list_for_each_entry_rcu(mh, &node->send_queue, list) {
469 if (before(seq1: mh->seq, seq2: seq)) {
470 dlm_mhandle_delete(node, mh);
471 } else {
472 /* send queue should be ordered */
473 break;
474 }
475 }
476 spin_unlock_bh(lock: &node->send_queue_lock);
477 rcu_read_unlock();
478}
479
480static void dlm_pas_fin_ack_rcv(struct midcomms_node *node)
481{
482 spin_lock(lock: &node->state_lock);
483 pr_debug("receive passive fin ack from node %d with state %s\n",
484 node->nodeid, dlm_state_str(node->state));
485
486 switch (node->state) {
487 case DLM_LAST_ACK:
488 /* DLM_CLOSED */
489 midcomms_node_reset(node);
490 break;
491 case DLM_CLOSED:
492 /* not valid but somehow we got what we want */
493 wake_up(&node->shutdown_wait);
494 break;
495 default:
496 spin_unlock(lock: &node->state_lock);
497 log_print("%s: unexpected state: %d",
498 __func__, node->state);
499 WARN_ON_ONCE(1);
500 return;
501 }
502 spin_unlock(lock: &node->state_lock);
503}
504
505static void dlm_receive_buffer_3_2_trace(uint32_t seq,
506 const union dlm_packet *p)
507{
508 switch (p->header.h_cmd) {
509 case DLM_MSG:
510 trace_dlm_recv_message(dst: dlm_our_nodeid(), h_seq: seq, ms: &p->message);
511 break;
512 case DLM_RCOM:
513 trace_dlm_recv_rcom(dst: dlm_our_nodeid(), h_seq: seq, rc: &p->rcom);
514 break;
515 default:
516 break;
517 }
518}
519
520static void dlm_midcomms_receive_buffer(const union dlm_packet *p,
521 struct midcomms_node *node,
522 uint32_t seq)
523{
524 bool is_expected_seq;
525 uint32_t oval, nval;
526
527 do {
528 oval = atomic_read(v: &node->seq_next);
529 is_expected_seq = (oval == seq);
530 if (!is_expected_seq)
531 break;
532
533 nval = oval + 1;
534 } while (atomic_cmpxchg(v: &node->seq_next, old: oval, new: nval) != oval);
535
536 if (is_expected_seq) {
537 switch (p->header.h_cmd) {
538 case DLM_FIN:
539 spin_lock(lock: &node->state_lock);
540 pr_debug("receive fin msg from node %d with state %s\n",
541 node->nodeid, dlm_state_str(node->state));
542
543 switch (node->state) {
544 case DLM_ESTABLISHED:
545 dlm_send_ack(nodeid: node->nodeid, seq: nval);
546
547 /* passive shutdown DLM_LAST_ACK case 1
548 * additional we check if the node is used by
549 * cluster manager events at all.
550 */
551 if (node->users == 0) {
552 node->state = DLM_LAST_ACK;
553 pr_debug("switch node %d to state %s case 1\n",
554 node->nodeid, dlm_state_str(node->state));
555 set_bit(DLM_NODE_FLAG_STOP_RX, addr: &node->flags);
556 dlm_send_fin(node, ack_rcv: dlm_pas_fin_ack_rcv);
557 } else {
558 node->state = DLM_CLOSE_WAIT;
559 pr_debug("switch node %d to state %s\n",
560 node->nodeid, dlm_state_str(node->state));
561 }
562 break;
563 case DLM_FIN_WAIT1:
564 dlm_send_ack(nodeid: node->nodeid, seq: nval);
565 node->state = DLM_CLOSING;
566 set_bit(DLM_NODE_FLAG_STOP_RX, addr: &node->flags);
567 pr_debug("switch node %d to state %s\n",
568 node->nodeid, dlm_state_str(node->state));
569 break;
570 case DLM_FIN_WAIT2:
571 dlm_send_ack(nodeid: node->nodeid, seq: nval);
572 midcomms_node_reset(node);
573 pr_debug("switch node %d to state %s\n",
574 node->nodeid, dlm_state_str(node->state));
575 break;
576 case DLM_LAST_ACK:
577 /* probably remove_member caught it, do nothing */
578 break;
579 default:
580 spin_unlock(lock: &node->state_lock);
581 log_print("%s: unexpected state: %d",
582 __func__, node->state);
583 WARN_ON_ONCE(1);
584 return;
585 }
586 spin_unlock(lock: &node->state_lock);
587 break;
588 default:
589 WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_RX, &node->flags));
590 dlm_receive_buffer_3_2_trace(seq, p);
591 dlm_receive_buffer(p, nodeid: node->nodeid);
592 atomic_inc(v: &node->ulp_delivered);
593 /* unlikely case to send ack back when we don't transmit */
594 dlm_send_ack_threshold(node, DLM_RECV_ACK_BACK_MSG_THRESHOLD);
595 break;
596 }
597 } else {
598 /* retry to ack message which we already have by sending back
599 * current node->seq_next number as ack.
600 */
601 if (seq < oval)
602 dlm_send_ack(nodeid: node->nodeid, seq: oval);
603
604 log_print_ratelimited("ignore dlm msg because seq mismatch, seq: %u, expected: %u, nodeid: %d",
605 seq, oval, node->nodeid);
606 }
607}
608
609static int dlm_opts_check_msglen(const union dlm_packet *p, uint16_t msglen,
610 int nodeid)
611{
612 int len = msglen;
613
614 /* we only trust outer header msglen because
615 * it's checked against receive buffer length.
616 */
617 if (len < sizeof(struct dlm_opts))
618 return -1;
619 len -= sizeof(struct dlm_opts);
620
621 if (len < le16_to_cpu(p->opts.o_optlen))
622 return -1;
623 len -= le16_to_cpu(p->opts.o_optlen);
624
625 switch (p->opts.o_nextcmd) {
626 case DLM_FIN:
627 if (len < sizeof(struct dlm_header)) {
628 log_print("fin too small: %d, will skip this message from node %d",
629 len, nodeid);
630 return -1;
631 }
632
633 break;
634 case DLM_MSG:
635 if (len < sizeof(struct dlm_message)) {
636 log_print("msg too small: %d, will skip this message from node %d",
637 msglen, nodeid);
638 return -1;
639 }
640
641 break;
642 case DLM_RCOM:
643 if (len < sizeof(struct dlm_rcom)) {
644 log_print("rcom msg too small: %d, will skip this message from node %d",
645 len, nodeid);
646 return -1;
647 }
648
649 break;
650 default:
651 log_print("unsupported o_nextcmd received: %u, will skip this message from node %d",
652 p->opts.o_nextcmd, nodeid);
653 return -1;
654 }
655
656 return 0;
657}
658
659static void dlm_midcomms_receive_buffer_3_2(const union dlm_packet *p, int nodeid)
660{
661 uint16_t msglen = le16_to_cpu(p->header.h_length);
662 struct midcomms_node *node;
663 uint32_t seq;
664 int ret, idx;
665
666 idx = srcu_read_lock(ssp: &nodes_srcu);
667 node = nodeid2node(nodeid);
668 if (WARN_ON_ONCE(!node))
669 goto out;
670
671 switch (node->version) {
672 case DLM_VERSION_NOT_SET:
673 node->version = DLM_VERSION_3_2;
674 wake_up(&node->shutdown_wait);
675 log_print("version 0x%08x for node %d detected", DLM_VERSION_3_2,
676 node->nodeid);
677
678 spin_lock(lock: &node->state_lock);
679 switch (node->state) {
680 case DLM_CLOSED:
681 node->state = DLM_ESTABLISHED;
682 pr_debug("switch node %d to state %s\n",
683 node->nodeid, dlm_state_str(node->state));
684 break;
685 default:
686 break;
687 }
688 spin_unlock(lock: &node->state_lock);
689
690 break;
691 case DLM_VERSION_3_2:
692 break;
693 default:
694 log_print_ratelimited("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
695 DLM_VERSION_3_2, node->nodeid, node->version);
696 goto out;
697 }
698
699 switch (p->header.h_cmd) {
700 case DLM_RCOM:
701 /* these rcom message we use to determine version.
702 * they have their own retransmission handling and
703 * are the first messages of dlm.
704 *
705 * length already checked.
706 */
707 switch (p->rcom.rc_type) {
708 case cpu_to_le32(DLM_RCOM_NAMES):
709 fallthrough;
710 case cpu_to_le32(DLM_RCOM_NAMES_REPLY):
711 fallthrough;
712 case cpu_to_le32(DLM_RCOM_STATUS):
713 fallthrough;
714 case cpu_to_le32(DLM_RCOM_STATUS_REPLY):
715 break;
716 default:
717 log_print("unsupported rcom type received: %u, will skip this message from node %d",
718 le32_to_cpu(p->rcom.rc_type), nodeid);
719 goto out;
720 }
721
722 WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_RX, &node->flags));
723 dlm_receive_buffer(p, nodeid);
724 break;
725 case DLM_OPTS:
726 seq = le32_to_cpu(p->header.u.h_seq);
727
728 ret = dlm_opts_check_msglen(p, msglen, nodeid);
729 if (ret < 0) {
730 log_print("opts msg too small: %u, will skip this message from node %d",
731 msglen, nodeid);
732 goto out;
733 }
734
735 p = (union dlm_packet *)((unsigned char *)p->opts.o_opts +
736 le16_to_cpu(p->opts.o_optlen));
737
738 /* recheck inner msglen just if it's not garbage */
739 msglen = le16_to_cpu(p->header.h_length);
740 switch (p->header.h_cmd) {
741 case DLM_RCOM:
742 if (msglen < sizeof(struct dlm_rcom)) {
743 log_print("inner rcom msg too small: %u, will skip this message from node %d",
744 msglen, nodeid);
745 goto out;
746 }
747
748 break;
749 case DLM_MSG:
750 if (msglen < sizeof(struct dlm_message)) {
751 log_print("inner msg too small: %u, will skip this message from node %d",
752 msglen, nodeid);
753 goto out;
754 }
755
756 break;
757 case DLM_FIN:
758 if (msglen < sizeof(struct dlm_header)) {
759 log_print("inner fin too small: %u, will skip this message from node %d",
760 msglen, nodeid);
761 goto out;
762 }
763
764 break;
765 default:
766 log_print("unsupported inner h_cmd received: %u, will skip this message from node %d",
767 msglen, nodeid);
768 goto out;
769 }
770
771 dlm_midcomms_receive_buffer(p, node, seq);
772 break;
773 case DLM_ACK:
774 seq = le32_to_cpu(p->header.u.h_seq);
775 dlm_receive_ack(node, seq);
776 break;
777 default:
778 log_print("unsupported h_cmd received: %u, will skip this message from node %d",
779 p->header.h_cmd, nodeid);
780 break;
781 }
782
783out:
784 srcu_read_unlock(ssp: &nodes_srcu, idx);
785}
786
787static void dlm_midcomms_receive_buffer_3_1(const union dlm_packet *p, int nodeid)
788{
789 uint16_t msglen = le16_to_cpu(p->header.h_length);
790 struct midcomms_node *node;
791 int idx;
792
793 idx = srcu_read_lock(ssp: &nodes_srcu);
794 node = nodeid2node(nodeid);
795 if (WARN_ON_ONCE(!node)) {
796 srcu_read_unlock(ssp: &nodes_srcu, idx);
797 return;
798 }
799
800 switch (node->version) {
801 case DLM_VERSION_NOT_SET:
802 node->version = DLM_VERSION_3_1;
803 wake_up(&node->shutdown_wait);
804 log_print("version 0x%08x for node %d detected", DLM_VERSION_3_1,
805 node->nodeid);
806 break;
807 case DLM_VERSION_3_1:
808 break;
809 default:
810 log_print_ratelimited("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
811 DLM_VERSION_3_1, node->nodeid, node->version);
812 srcu_read_unlock(ssp: &nodes_srcu, idx);
813 return;
814 }
815 srcu_read_unlock(ssp: &nodes_srcu, idx);
816
817 switch (p->header.h_cmd) {
818 case DLM_RCOM:
819 /* length already checked */
820 break;
821 case DLM_MSG:
822 if (msglen < sizeof(struct dlm_message)) {
823 log_print("msg too small: %u, will skip this message from node %d",
824 msglen, nodeid);
825 return;
826 }
827
828 break;
829 default:
830 log_print("unsupported h_cmd received: %u, will skip this message from node %d",
831 p->header.h_cmd, nodeid);
832 return;
833 }
834
835 dlm_receive_buffer(p, nodeid);
836}
837
838int dlm_validate_incoming_buffer(int nodeid, unsigned char *buf, int len)
839{
840 const unsigned char *ptr = buf;
841 const struct dlm_header *hd;
842 uint16_t msglen;
843 int ret = 0;
844
845 while (len >= sizeof(struct dlm_header)) {
846 hd = (struct dlm_header *)ptr;
847
848 /* no message should be more than DLM_MAX_SOCKET_BUFSIZE or
849 * less than dlm_header size.
850 *
851 * Some messages does not have a 8 byte length boundary yet
852 * which can occur in a unaligned memory access of some dlm
853 * messages. However this problem need to be fixed at the
854 * sending side, for now it seems nobody run into architecture
855 * related issues yet but it slows down some processing.
856 * Fixing this issue should be scheduled in future by doing
857 * the next major version bump.
858 */
859 msglen = le16_to_cpu(hd->h_length);
860 if (msglen > DLM_MAX_SOCKET_BUFSIZE ||
861 msglen < sizeof(struct dlm_header)) {
862 log_print("received invalid length header: %u from node %d, will abort message parsing",
863 msglen, nodeid);
864 return -EBADMSG;
865 }
866
867 /* caller will take care that leftover
868 * will be parsed next call with more data
869 */
870 if (msglen > len)
871 break;
872
873 ret += msglen;
874 len -= msglen;
875 ptr += msglen;
876 }
877
878 return ret;
879}
880
881/*
882 * Called from the low-level comms layer to process a buffer of
883 * commands.
884 */
885int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int len)
886{
887 const unsigned char *ptr = buf;
888 const struct dlm_header *hd;
889 uint16_t msglen;
890 int ret = 0;
891
892 while (len >= sizeof(struct dlm_header)) {
893 hd = (struct dlm_header *)ptr;
894
895 msglen = le16_to_cpu(hd->h_length);
896 if (msglen > len)
897 break;
898
899 switch (hd->h_version) {
900 case cpu_to_le32(DLM_VERSION_3_1):
901 dlm_midcomms_receive_buffer_3_1(p: (const union dlm_packet *)ptr, nodeid);
902 break;
903 case cpu_to_le32(DLM_VERSION_3_2):
904 dlm_midcomms_receive_buffer_3_2(p: (const union dlm_packet *)ptr, nodeid);
905 break;
906 default:
907 log_print("received invalid version header: %u from node %d, will skip this message",
908 le32_to_cpu(hd->h_version), nodeid);
909 break;
910 }
911
912 ret += msglen;
913 len -= msglen;
914 ptr += msglen;
915 }
916
917 return ret;
918}
919
920void dlm_midcomms_unack_msg_resend(int nodeid)
921{
922 struct midcomms_node *node;
923 struct dlm_mhandle *mh;
924 int idx, ret;
925
926 idx = srcu_read_lock(ssp: &nodes_srcu);
927 node = nodeid2node(nodeid);
928 if (WARN_ON_ONCE(!node)) {
929 srcu_read_unlock(ssp: &nodes_srcu, idx);
930 return;
931 }
932
933 /* old protocol, we don't support to retransmit on failure */
934 switch (node->version) {
935 case DLM_VERSION_3_2:
936 break;
937 default:
938 srcu_read_unlock(ssp: &nodes_srcu, idx);
939 return;
940 }
941
942 rcu_read_lock();
943 list_for_each_entry_rcu(mh, &node->send_queue, list) {
944 if (!mh->committed)
945 continue;
946
947 ret = dlm_lowcomms_resend_msg(msg: mh->msg);
948 if (!ret)
949 log_print_ratelimited("retransmit dlm msg, seq %u, nodeid %d",
950 mh->seq, node->nodeid);
951 }
952 rcu_read_unlock();
953 srcu_read_unlock(ssp: &nodes_srcu, idx);
954}
955
956static void dlm_fill_opts_header(struct dlm_opts *opts, uint16_t inner_len,
957 uint32_t seq)
958{
959 opts->o_header.h_cmd = DLM_OPTS;
960 opts->o_header.h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
961 opts->o_header.h_nodeid = cpu_to_le32(dlm_our_nodeid());
962 opts->o_header.h_length = cpu_to_le16(DLM_MIDCOMMS_OPT_LEN + inner_len);
963 opts->o_header.u.h_seq = cpu_to_le32(seq);
964}
965
966static void midcomms_new_msg_cb(void *data)
967{
968 struct dlm_mhandle *mh = data;
969
970 atomic_inc(v: &mh->node->send_queue_cnt);
971
972 spin_lock_bh(lock: &mh->node->send_queue_lock);
973 list_add_tail_rcu(new: &mh->list, head: &mh->node->send_queue);
974 spin_unlock_bh(lock: &mh->node->send_queue_lock);
975
976 mh->seq = atomic_fetch_inc(v: &mh->node->seq_send);
977}
978
979static struct dlm_msg *dlm_midcomms_get_msg_3_2(struct dlm_mhandle *mh, int nodeid,
980 int len, gfp_t allocation, char **ppc)
981{
982 struct dlm_opts *opts;
983 struct dlm_msg *msg;
984
985 msg = dlm_lowcomms_new_msg(nodeid, len: len + DLM_MIDCOMMS_OPT_LEN,
986 allocation, ppc, cb: midcomms_new_msg_cb, data: mh);
987 if (!msg)
988 return NULL;
989
990 opts = (struct dlm_opts *)*ppc;
991 mh->opts = opts;
992
993 /* add possible options here */
994 dlm_fill_opts_header(opts, inner_len: len, seq: mh->seq);
995
996 *ppc += sizeof(*opts);
997 mh->inner_p = (const union dlm_packet *)*ppc;
998 return msg;
999}
1000
1001/* avoid false positive for nodes_srcu, unlock happens in
1002 * dlm_midcomms_commit_mhandle which is a must call if success
1003 */
1004#ifndef __CHECKER__
1005struct dlm_mhandle *dlm_midcomms_get_mhandle(int nodeid, int len,
1006 gfp_t allocation, char **ppc)
1007{
1008 struct midcomms_node *node;
1009 struct dlm_mhandle *mh;
1010 struct dlm_msg *msg;
1011 int idx;
1012
1013 idx = srcu_read_lock(ssp: &nodes_srcu);
1014 node = nodeid2node(nodeid);
1015 if (WARN_ON_ONCE(!node))
1016 goto err;
1017
1018 /* this is a bug, however we going on and hope it will be resolved */
1019 WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_TX, &node->flags));
1020
1021 mh = dlm_allocate_mhandle(allocation);
1022 if (!mh)
1023 goto err;
1024
1025 mh->committed = false;
1026 mh->ack_rcv = NULL;
1027 mh->idx = idx;
1028 mh->node = node;
1029
1030 switch (node->version) {
1031 case DLM_VERSION_3_1:
1032 msg = dlm_lowcomms_new_msg(nodeid, len, allocation, ppc,
1033 NULL, NULL);
1034 if (!msg) {
1035 dlm_free_mhandle(mhandle: mh);
1036 goto err;
1037 }
1038
1039 break;
1040 case DLM_VERSION_3_2:
1041 /* send ack back if necessary */
1042 dlm_send_ack_threshold(node, DLM_SEND_ACK_BACK_MSG_THRESHOLD);
1043
1044 msg = dlm_midcomms_get_msg_3_2(mh, nodeid, len, allocation,
1045 ppc);
1046 if (!msg) {
1047 dlm_free_mhandle(mhandle: mh);
1048 goto err;
1049 }
1050 break;
1051 default:
1052 dlm_free_mhandle(mhandle: mh);
1053 WARN_ON_ONCE(1);
1054 goto err;
1055 }
1056
1057 mh->msg = msg;
1058
1059 /* keep in mind that is a must to call
1060 * dlm_midcomms_commit_msg() which releases
1061 * nodes_srcu using mh->idx which is assumed
1062 * here that the application will call it.
1063 */
1064 return mh;
1065
1066err:
1067 srcu_read_unlock(ssp: &nodes_srcu, idx);
1068 return NULL;
1069}
1070#endif
1071
1072static void dlm_midcomms_commit_msg_3_2_trace(const struct dlm_mhandle *mh,
1073 const void *name, int namelen)
1074{
1075 switch (mh->inner_p->header.h_cmd) {
1076 case DLM_MSG:
1077 trace_dlm_send_message(dst: mh->node->nodeid, h_seq: mh->seq,
1078 ms: &mh->inner_p->message,
1079 name, namelen);
1080 break;
1081 case DLM_RCOM:
1082 trace_dlm_send_rcom(dst: mh->node->nodeid, h_seq: mh->seq,
1083 rc: &mh->inner_p->rcom);
1084 break;
1085 default:
1086 /* nothing to trace */
1087 break;
1088 }
1089}
1090
1091static void dlm_midcomms_commit_msg_3_2(struct dlm_mhandle *mh,
1092 const void *name, int namelen)
1093{
1094 /* nexthdr chain for fast lookup */
1095 mh->opts->o_nextcmd = mh->inner_p->header.h_cmd;
1096 mh->committed = true;
1097 dlm_midcomms_commit_msg_3_2_trace(mh, name, namelen);
1098 dlm_lowcomms_commit_msg(msg: mh->msg);
1099}
1100
1101/* avoid false positive for nodes_srcu, lock was happen in
1102 * dlm_midcomms_get_mhandle
1103 */
1104#ifndef __CHECKER__
1105void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh,
1106 const void *name, int namelen)
1107{
1108
1109 switch (mh->node->version) {
1110 case DLM_VERSION_3_1:
1111 srcu_read_unlock(ssp: &nodes_srcu, idx: mh->idx);
1112
1113 dlm_lowcomms_commit_msg(msg: mh->msg);
1114 dlm_lowcomms_put_msg(msg: mh->msg);
1115 /* mh is not part of rcu list in this case */
1116 dlm_free_mhandle(mhandle: mh);
1117 break;
1118 case DLM_VERSION_3_2:
1119 /* held rcu read lock here, because we sending the
1120 * dlm message out, when we do that we could receive
1121 * an ack back which releases the mhandle and we
1122 * get a use after free.
1123 */
1124 rcu_read_lock();
1125 dlm_midcomms_commit_msg_3_2(mh, name, namelen);
1126 srcu_read_unlock(ssp: &nodes_srcu, idx: mh->idx);
1127 rcu_read_unlock();
1128 break;
1129 default:
1130 srcu_read_unlock(ssp: &nodes_srcu, idx: mh->idx);
1131 WARN_ON_ONCE(1);
1132 break;
1133 }
1134}
1135#endif
1136
1137int dlm_midcomms_start(void)
1138{
1139 return dlm_lowcomms_start();
1140}
1141
1142void dlm_midcomms_stop(void)
1143{
1144 dlm_lowcomms_stop();
1145}
1146
1147void dlm_midcomms_init(void)
1148{
1149 int i;
1150
1151 for (i = 0; i < CONN_HASH_SIZE; i++)
1152 INIT_HLIST_HEAD(&node_hash[i]);
1153
1154 dlm_lowcomms_init();
1155}
1156
1157static void midcomms_node_release(struct rcu_head *rcu)
1158{
1159 struct midcomms_node *node = container_of(rcu, struct midcomms_node, rcu);
1160
1161 WARN_ON_ONCE(atomic_read(&node->send_queue_cnt));
1162 dlm_send_queue_flush(node);
1163 kfree(objp: node);
1164}
1165
1166void dlm_midcomms_exit(void)
1167{
1168 struct midcomms_node *node;
1169 int i, idx;
1170
1171 idx = srcu_read_lock(ssp: &nodes_srcu);
1172 for (i = 0; i < CONN_HASH_SIZE; i++) {
1173 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1174 dlm_delete_debug_comms_file(ctx: node->debugfs);
1175
1176 spin_lock(lock: &nodes_lock);
1177 hlist_del_rcu(n: &node->hlist);
1178 spin_unlock(lock: &nodes_lock);
1179
1180 call_srcu(ssp: &nodes_srcu, head: &node->rcu, func: midcomms_node_release);
1181 }
1182 }
1183 srcu_read_unlock(ssp: &nodes_srcu, idx);
1184
1185 dlm_lowcomms_exit();
1186}
1187
1188static void dlm_act_fin_ack_rcv(struct midcomms_node *node)
1189{
1190 spin_lock(lock: &node->state_lock);
1191 pr_debug("receive active fin ack from node %d with state %s\n",
1192 node->nodeid, dlm_state_str(node->state));
1193
1194 switch (node->state) {
1195 case DLM_FIN_WAIT1:
1196 node->state = DLM_FIN_WAIT2;
1197 pr_debug("switch node %d to state %s\n",
1198 node->nodeid, dlm_state_str(node->state));
1199 break;
1200 case DLM_CLOSING:
1201 midcomms_node_reset(node);
1202 pr_debug("switch node %d to state %s\n",
1203 node->nodeid, dlm_state_str(node->state));
1204 break;
1205 case DLM_CLOSED:
1206 /* not valid but somehow we got what we want */
1207 wake_up(&node->shutdown_wait);
1208 break;
1209 default:
1210 spin_unlock(lock: &node->state_lock);
1211 log_print("%s: unexpected state: %d",
1212 __func__, node->state);
1213 WARN_ON_ONCE(1);
1214 return;
1215 }
1216 spin_unlock(lock: &node->state_lock);
1217}
1218
1219void dlm_midcomms_add_member(int nodeid)
1220{
1221 struct midcomms_node *node;
1222 int idx;
1223
1224 idx = srcu_read_lock(ssp: &nodes_srcu);
1225 node = nodeid2node(nodeid);
1226 if (WARN_ON_ONCE(!node)) {
1227 srcu_read_unlock(ssp: &nodes_srcu, idx);
1228 return;
1229 }
1230
1231 spin_lock(lock: &node->state_lock);
1232 if (!node->users) {
1233 pr_debug("receive add member from node %d with state %s\n",
1234 node->nodeid, dlm_state_str(node->state));
1235 switch (node->state) {
1236 case DLM_ESTABLISHED:
1237 break;
1238 case DLM_CLOSED:
1239 node->state = DLM_ESTABLISHED;
1240 pr_debug("switch node %d to state %s\n",
1241 node->nodeid, dlm_state_str(node->state));
1242 break;
1243 default:
1244 /* some invalid state passive shutdown
1245 * was failed, we try to reset and
1246 * hope it will go on.
1247 */
1248 log_print("reset node %d because shutdown stuck",
1249 node->nodeid);
1250
1251 midcomms_node_reset(node);
1252 node->state = DLM_ESTABLISHED;
1253 break;
1254 }
1255 }
1256
1257 node->users++;
1258 pr_debug("node %d users inc count %d\n", nodeid, node->users);
1259 spin_unlock(lock: &node->state_lock);
1260
1261 srcu_read_unlock(ssp: &nodes_srcu, idx);
1262}
1263
1264void dlm_midcomms_remove_member(int nodeid)
1265{
1266 struct midcomms_node *node;
1267 int idx;
1268
1269 idx = srcu_read_lock(ssp: &nodes_srcu);
1270 node = nodeid2node(nodeid);
1271 /* in case of dlm_midcomms_close() removes node */
1272 if (!node) {
1273 srcu_read_unlock(ssp: &nodes_srcu, idx);
1274 return;
1275 }
1276
1277 spin_lock(lock: &node->state_lock);
1278 /* case of dlm_midcomms_addr() created node but
1279 * was not added before because dlm_midcomms_close()
1280 * removed the node
1281 */
1282 if (!node->users) {
1283 spin_unlock(lock: &node->state_lock);
1284 srcu_read_unlock(ssp: &nodes_srcu, idx);
1285 return;
1286 }
1287
1288 node->users--;
1289 pr_debug("node %d users dec count %d\n", nodeid, node->users);
1290
1291 /* hitting users count to zero means the
1292 * other side is running dlm_midcomms_stop()
1293 * we meet us to have a clean disconnect.
1294 */
1295 if (node->users == 0) {
1296 pr_debug("receive remove member from node %d with state %s\n",
1297 node->nodeid, dlm_state_str(node->state));
1298 switch (node->state) {
1299 case DLM_ESTABLISHED:
1300 break;
1301 case DLM_CLOSE_WAIT:
1302 /* passive shutdown DLM_LAST_ACK case 2 */
1303 node->state = DLM_LAST_ACK;
1304 pr_debug("switch node %d to state %s case 2\n",
1305 node->nodeid, dlm_state_str(node->state));
1306 set_bit(DLM_NODE_FLAG_STOP_RX, addr: &node->flags);
1307 dlm_send_fin(node, ack_rcv: dlm_pas_fin_ack_rcv);
1308 break;
1309 case DLM_LAST_ACK:
1310 /* probably receive fin caught it, do nothing */
1311 break;
1312 case DLM_CLOSED:
1313 /* already gone, do nothing */
1314 break;
1315 default:
1316 log_print("%s: unexpected state: %d",
1317 __func__, node->state);
1318 break;
1319 }
1320 }
1321 spin_unlock(lock: &node->state_lock);
1322
1323 srcu_read_unlock(ssp: &nodes_srcu, idx);
1324}
1325
1326void dlm_midcomms_version_wait(void)
1327{
1328 struct midcomms_node *node;
1329 int i, idx, ret;
1330
1331 idx = srcu_read_lock(ssp: &nodes_srcu);
1332 for (i = 0; i < CONN_HASH_SIZE; i++) {
1333 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1334 ret = wait_event_timeout(node->shutdown_wait,
1335 node->version != DLM_VERSION_NOT_SET ||
1336 node->state == DLM_CLOSED ||
1337 test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
1338 DLM_SHUTDOWN_TIMEOUT);
1339 if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags))
1340 pr_debug("version wait timed out for node %d with state %s\n",
1341 node->nodeid, dlm_state_str(node->state));
1342 }
1343 }
1344 srcu_read_unlock(ssp: &nodes_srcu, idx);
1345}
1346
1347static void midcomms_shutdown(struct midcomms_node *node)
1348{
1349 int ret;
1350
1351 /* old protocol, we don't wait for pending operations */
1352 switch (node->version) {
1353 case DLM_VERSION_3_2:
1354 break;
1355 default:
1356 return;
1357 }
1358
1359 spin_lock(lock: &node->state_lock);
1360 pr_debug("receive active shutdown for node %d with state %s\n",
1361 node->nodeid, dlm_state_str(node->state));
1362 switch (node->state) {
1363 case DLM_ESTABLISHED:
1364 node->state = DLM_FIN_WAIT1;
1365 pr_debug("switch node %d to state %s case 2\n",
1366 node->nodeid, dlm_state_str(node->state));
1367 dlm_send_fin(node, ack_rcv: dlm_act_fin_ack_rcv);
1368 break;
1369 case DLM_CLOSED:
1370 /* we have what we want */
1371 break;
1372 default:
1373 /* busy to enter DLM_FIN_WAIT1, wait until passive
1374 * done in shutdown_wait to enter DLM_CLOSED.
1375 */
1376 break;
1377 }
1378 spin_unlock(lock: &node->state_lock);
1379
1380 if (DLM_DEBUG_FENCE_TERMINATION)
1381 msleep(msecs: 5000);
1382
1383 /* wait for other side dlm + fin */
1384 ret = wait_event_timeout(node->shutdown_wait,
1385 node->state == DLM_CLOSED ||
1386 test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
1387 DLM_SHUTDOWN_TIMEOUT);
1388 if (!ret)
1389 pr_debug("active shutdown timed out for node %d with state %s\n",
1390 node->nodeid, dlm_state_str(node->state));
1391 else
1392 pr_debug("active shutdown done for node %d with state %s\n",
1393 node->nodeid, dlm_state_str(node->state));
1394}
1395
1396void dlm_midcomms_shutdown(void)
1397{
1398 struct midcomms_node *node;
1399 int i, idx;
1400
1401 mutex_lock(&close_lock);
1402 idx = srcu_read_lock(ssp: &nodes_srcu);
1403 for (i = 0; i < CONN_HASH_SIZE; i++) {
1404 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1405 midcomms_shutdown(node);
1406 }
1407 }
1408
1409 dlm_lowcomms_shutdown();
1410
1411 for (i = 0; i < CONN_HASH_SIZE; i++) {
1412 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1413 midcomms_node_reset(node);
1414 }
1415 }
1416 srcu_read_unlock(ssp: &nodes_srcu, idx);
1417 mutex_unlock(lock: &close_lock);
1418}
1419
1420int dlm_midcomms_close(int nodeid)
1421{
1422 struct midcomms_node *node;
1423 int idx, ret;
1424
1425 idx = srcu_read_lock(ssp: &nodes_srcu);
1426 /* Abort pending close/remove operation */
1427 node = nodeid2node(nodeid);
1428 if (node) {
1429 /* let shutdown waiters leave */
1430 set_bit(DLM_NODE_FLAG_CLOSE, addr: &node->flags);
1431 wake_up(&node->shutdown_wait);
1432 }
1433 srcu_read_unlock(ssp: &nodes_srcu, idx);
1434
1435 synchronize_srcu(ssp: &nodes_srcu);
1436
1437 mutex_lock(&close_lock);
1438 idx = srcu_read_lock(ssp: &nodes_srcu);
1439 node = nodeid2node(nodeid);
1440 if (!node) {
1441 srcu_read_unlock(ssp: &nodes_srcu, idx);
1442 mutex_unlock(lock: &close_lock);
1443 return dlm_lowcomms_close(nodeid);
1444 }
1445
1446 ret = dlm_lowcomms_close(nodeid);
1447 dlm_delete_debug_comms_file(ctx: node->debugfs);
1448
1449 spin_lock(lock: &nodes_lock);
1450 hlist_del_rcu(n: &node->hlist);
1451 spin_unlock(lock: &nodes_lock);
1452 srcu_read_unlock(ssp: &nodes_srcu, idx);
1453
1454 /* wait that all readers left until flush send queue */
1455 synchronize_srcu(ssp: &nodes_srcu);
1456
1457 /* drop all pending dlm messages, this is fine as
1458 * this function get called when the node is fenced
1459 */
1460 dlm_send_queue_flush(node);
1461
1462 call_srcu(ssp: &nodes_srcu, head: &node->rcu, func: midcomms_node_release);
1463 mutex_unlock(lock: &close_lock);
1464
1465 return ret;
1466}
1467
1468/* debug functionality to send raw dlm msg from user space */
1469struct dlm_rawmsg_data {
1470 struct midcomms_node *node;
1471 void *buf;
1472};
1473
1474static void midcomms_new_rawmsg_cb(void *data)
1475{
1476 struct dlm_rawmsg_data *rd = data;
1477 struct dlm_header *h = rd->buf;
1478
1479 switch (h->h_version) {
1480 case cpu_to_le32(DLM_VERSION_3_1):
1481 break;
1482 default:
1483 switch (h->h_cmd) {
1484 case DLM_OPTS:
1485 if (!h->u.h_seq)
1486 h->u.h_seq = cpu_to_le32(atomic_fetch_inc(&rd->node->seq_send));
1487 break;
1488 default:
1489 break;
1490 }
1491 break;
1492 }
1493}
1494
1495int dlm_midcomms_rawmsg_send(struct midcomms_node *node, void *buf,
1496 int buflen)
1497{
1498 struct dlm_rawmsg_data rd;
1499 struct dlm_msg *msg;
1500 char *msgbuf;
1501
1502 rd.node = node;
1503 rd.buf = buf;
1504
1505 msg = dlm_lowcomms_new_msg(nodeid: node->nodeid, len: buflen, GFP_NOFS,
1506 ppc: &msgbuf, cb: midcomms_new_rawmsg_cb, data: &rd);
1507 if (!msg)
1508 return -ENOMEM;
1509
1510 memcpy(msgbuf, buf, buflen);
1511 dlm_lowcomms_commit_msg(msg);
1512 return 0;
1513}
1514
1515

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