xref: /linux/net/ceph/mon_client.c (revision 3213486f2e442831e324cc6201a2f9e924ecc235)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/ceph/ceph_debug.h>
3 
4 #include <linux/module.h>
5 #include <linux/types.h>
6 #include <linux/slab.h>
7 #include <linux/random.h>
8 #include <linux/sched.h>
9 
10 #include <linux/ceph/ceph_features.h>
11 #include <linux/ceph/mon_client.h>
12 #include <linux/ceph/libceph.h>
13 #include <linux/ceph/debugfs.h>
14 #include <linux/ceph/decode.h>
15 #include <linux/ceph/auth.h>
16 
17 /*
18  * Interact with Ceph monitor cluster.  Handle requests for new map
19  * versions, and periodically resend as needed.  Also implement
20  * statfs() and umount().
21  *
22  * A small cluster of Ceph "monitors" are responsible for managing critical
23  * cluster configuration and state information.  An odd number (e.g., 3, 5)
24  * of cmon daemons use a modified version of the Paxos part-time parliament
25  * algorithm to manage the MDS map (mds cluster membership), OSD map, and
26  * list of clients who have mounted the file system.
27  *
28  * We maintain an open, active session with a monitor at all times in order to
29  * receive timely MDSMap updates.  We periodically send a keepalive byte on the
30  * TCP socket to ensure we detect a failure.  If the connection does break, we
31  * randomly hunt for a new monitor.  Once the connection is reestablished, we
32  * resend any outstanding requests.
33  */
34 
35 static const struct ceph_connection_operations mon_con_ops;
36 
37 static int __validate_auth(struct ceph_mon_client *monc);
38 
39 /*
40  * Decode a monmap blob (e.g., during mount).
41  */
42 struct ceph_monmap *ceph_monmap_decode(void *p, void *end)
43 {
44 	struct ceph_monmap *m = NULL;
45 	int i, err = -EINVAL;
46 	struct ceph_fsid fsid;
47 	u32 epoch, num_mon;
48 	u32 len;
49 
50 	ceph_decode_32_safe(&p, end, len, bad);
51 	ceph_decode_need(&p, end, len, bad);
52 
53 	dout("monmap_decode %p %p len %d\n", p, end, (int)(end-p));
54 	p += sizeof(u16);  /* skip version */
55 
56 	ceph_decode_need(&p, end, sizeof(fsid) + 2*sizeof(u32), bad);
57 	ceph_decode_copy(&p, &fsid, sizeof(fsid));
58 	epoch = ceph_decode_32(&p);
59 
60 	num_mon = ceph_decode_32(&p);
61 	ceph_decode_need(&p, end, num_mon*sizeof(m->mon_inst[0]), bad);
62 
63 	if (num_mon > CEPH_MAX_MON)
64 		goto bad;
65 	m = kmalloc(struct_size(m, mon_inst, num_mon), GFP_NOFS);
66 	if (m == NULL)
67 		return ERR_PTR(-ENOMEM);
68 	m->fsid = fsid;
69 	m->epoch = epoch;
70 	m->num_mon = num_mon;
71 	ceph_decode_copy(&p, m->mon_inst, num_mon*sizeof(m->mon_inst[0]));
72 	for (i = 0; i < num_mon; i++)
73 		ceph_decode_addr(&m->mon_inst[i].addr);
74 
75 	dout("monmap_decode epoch %d, num_mon %d\n", m->epoch,
76 	     m->num_mon);
77 	for (i = 0; i < m->num_mon; i++)
78 		dout("monmap_decode  mon%d is %s\n", i,
79 		     ceph_pr_addr(&m->mon_inst[i].addr.in_addr));
80 	return m;
81 
82 bad:
83 	dout("monmap_decode failed with %d\n", err);
84 	kfree(m);
85 	return ERR_PTR(err);
86 }
87 
88 /*
89  * return true if *addr is included in the monmap.
90  */
91 int ceph_monmap_contains(struct ceph_monmap *m, struct ceph_entity_addr *addr)
92 {
93 	int i;
94 
95 	for (i = 0; i < m->num_mon; i++)
96 		if (memcmp(addr, &m->mon_inst[i].addr, sizeof(*addr)) == 0)
97 			return 1;
98 	return 0;
99 }
100 
101 /*
102  * Send an auth request.
103  */
104 static void __send_prepared_auth_request(struct ceph_mon_client *monc, int len)
105 {
106 	monc->pending_auth = 1;
107 	monc->m_auth->front.iov_len = len;
108 	monc->m_auth->hdr.front_len = cpu_to_le32(len);
109 	ceph_msg_revoke(monc->m_auth);
110 	ceph_msg_get(monc->m_auth);  /* keep our ref */
111 	ceph_con_send(&monc->con, monc->m_auth);
112 }
113 
114 /*
115  * Close monitor session, if any.
116  */
117 static void __close_session(struct ceph_mon_client *monc)
118 {
119 	dout("__close_session closing mon%d\n", monc->cur_mon);
120 	ceph_msg_revoke(monc->m_auth);
121 	ceph_msg_revoke_incoming(monc->m_auth_reply);
122 	ceph_msg_revoke(monc->m_subscribe);
123 	ceph_msg_revoke_incoming(monc->m_subscribe_ack);
124 	ceph_con_close(&monc->con);
125 
126 	monc->pending_auth = 0;
127 	ceph_auth_reset(monc->auth);
128 }
129 
130 /*
131  * Pick a new monitor at random and set cur_mon.  If we are repicking
132  * (i.e. cur_mon is already set), be sure to pick a different one.
133  */
134 static void pick_new_mon(struct ceph_mon_client *monc)
135 {
136 	int old_mon = monc->cur_mon;
137 
138 	BUG_ON(monc->monmap->num_mon < 1);
139 
140 	if (monc->monmap->num_mon == 1) {
141 		monc->cur_mon = 0;
142 	} else {
143 		int max = monc->monmap->num_mon;
144 		int o = -1;
145 		int n;
146 
147 		if (monc->cur_mon >= 0) {
148 			if (monc->cur_mon < monc->monmap->num_mon)
149 				o = monc->cur_mon;
150 			if (o >= 0)
151 				max--;
152 		}
153 
154 		n = prandom_u32() % max;
155 		if (o >= 0 && n >= o)
156 			n++;
157 
158 		monc->cur_mon = n;
159 	}
160 
161 	dout("%s mon%d -> mon%d out of %d mons\n", __func__, old_mon,
162 	     monc->cur_mon, monc->monmap->num_mon);
163 }
164 
165 /*
166  * Open a session with a new monitor.
167  */
168 static void __open_session(struct ceph_mon_client *monc)
169 {
170 	int ret;
171 
172 	pick_new_mon(monc);
173 
174 	monc->hunting = true;
175 	if (monc->had_a_connection) {
176 		monc->hunt_mult *= CEPH_MONC_HUNT_BACKOFF;
177 		if (monc->hunt_mult > CEPH_MONC_HUNT_MAX_MULT)
178 			monc->hunt_mult = CEPH_MONC_HUNT_MAX_MULT;
179 	}
180 
181 	monc->sub_renew_after = jiffies; /* i.e., expired */
182 	monc->sub_renew_sent = 0;
183 
184 	dout("%s opening mon%d\n", __func__, monc->cur_mon);
185 	ceph_con_open(&monc->con, CEPH_ENTITY_TYPE_MON, monc->cur_mon,
186 		      &monc->monmap->mon_inst[monc->cur_mon].addr);
187 
188 	/*
189 	 * send an initial keepalive to ensure our timestamp is valid
190 	 * by the time we are in an OPENED state
191 	 */
192 	ceph_con_keepalive(&monc->con);
193 
194 	/* initiate authentication handshake */
195 	ret = ceph_auth_build_hello(monc->auth,
196 				    monc->m_auth->front.iov_base,
197 				    monc->m_auth->front_alloc_len);
198 	BUG_ON(ret <= 0);
199 	__send_prepared_auth_request(monc, ret);
200 }
201 
202 static void reopen_session(struct ceph_mon_client *monc)
203 {
204 	if (!monc->hunting)
205 		pr_info("mon%d %s session lost, hunting for new mon\n",
206 		    monc->cur_mon, ceph_pr_addr(&monc->con.peer_addr.in_addr));
207 
208 	__close_session(monc);
209 	__open_session(monc);
210 }
211 
212 static void un_backoff(struct ceph_mon_client *monc)
213 {
214 	monc->hunt_mult /= 2; /* reduce by 50% */
215 	if (monc->hunt_mult < 1)
216 		monc->hunt_mult = 1;
217 	dout("%s hunt_mult now %d\n", __func__, monc->hunt_mult);
218 }
219 
220 /*
221  * Reschedule delayed work timer.
222  */
223 static void __schedule_delayed(struct ceph_mon_client *monc)
224 {
225 	unsigned long delay;
226 
227 	if (monc->hunting)
228 		delay = CEPH_MONC_HUNT_INTERVAL * monc->hunt_mult;
229 	else
230 		delay = CEPH_MONC_PING_INTERVAL;
231 
232 	dout("__schedule_delayed after %lu\n", delay);
233 	mod_delayed_work(system_wq, &monc->delayed_work,
234 			 round_jiffies_relative(delay));
235 }
236 
237 const char *ceph_sub_str[] = {
238 	[CEPH_SUB_MONMAP] = "monmap",
239 	[CEPH_SUB_OSDMAP] = "osdmap",
240 	[CEPH_SUB_FSMAP]  = "fsmap.user",
241 	[CEPH_SUB_MDSMAP] = "mdsmap",
242 };
243 
244 /*
245  * Send subscribe request for one or more maps, according to
246  * monc->subs.
247  */
248 static void __send_subscribe(struct ceph_mon_client *monc)
249 {
250 	struct ceph_msg *msg = monc->m_subscribe;
251 	void *p = msg->front.iov_base;
252 	void *const end = p + msg->front_alloc_len;
253 	int num = 0;
254 	int i;
255 
256 	dout("%s sent %lu\n", __func__, monc->sub_renew_sent);
257 
258 	BUG_ON(monc->cur_mon < 0);
259 
260 	if (!monc->sub_renew_sent)
261 		monc->sub_renew_sent = jiffies | 1; /* never 0 */
262 
263 	msg->hdr.version = cpu_to_le16(2);
264 
265 	for (i = 0; i < ARRAY_SIZE(monc->subs); i++) {
266 		if (monc->subs[i].want)
267 			num++;
268 	}
269 	BUG_ON(num < 1); /* monmap sub is always there */
270 	ceph_encode_32(&p, num);
271 	for (i = 0; i < ARRAY_SIZE(monc->subs); i++) {
272 		char buf[32];
273 		int len;
274 
275 		if (!monc->subs[i].want)
276 			continue;
277 
278 		len = sprintf(buf, "%s", ceph_sub_str[i]);
279 		if (i == CEPH_SUB_MDSMAP &&
280 		    monc->fs_cluster_id != CEPH_FS_CLUSTER_ID_NONE)
281 			len += sprintf(buf + len, ".%d", monc->fs_cluster_id);
282 
283 		dout("%s %s start %llu flags 0x%x\n", __func__, buf,
284 		     le64_to_cpu(monc->subs[i].item.start),
285 		     monc->subs[i].item.flags);
286 		ceph_encode_string(&p, end, buf, len);
287 		memcpy(p, &monc->subs[i].item, sizeof(monc->subs[i].item));
288 		p += sizeof(monc->subs[i].item);
289 	}
290 
291 	BUG_ON(p > end);
292 	msg->front.iov_len = p - msg->front.iov_base;
293 	msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
294 	ceph_msg_revoke(msg);
295 	ceph_con_send(&monc->con, ceph_msg_get(msg));
296 }
297 
298 static void handle_subscribe_ack(struct ceph_mon_client *monc,
299 				 struct ceph_msg *msg)
300 {
301 	unsigned int seconds;
302 	struct ceph_mon_subscribe_ack *h = msg->front.iov_base;
303 
304 	if (msg->front.iov_len < sizeof(*h))
305 		goto bad;
306 	seconds = le32_to_cpu(h->duration);
307 
308 	mutex_lock(&monc->mutex);
309 	if (monc->sub_renew_sent) {
310 		/*
311 		 * This is only needed for legacy (infernalis or older)
312 		 * MONs -- see delayed_work().
313 		 */
314 		monc->sub_renew_after = monc->sub_renew_sent +
315 					    (seconds >> 1) * HZ - 1;
316 		dout("%s sent %lu duration %d renew after %lu\n", __func__,
317 		     monc->sub_renew_sent, seconds, monc->sub_renew_after);
318 		monc->sub_renew_sent = 0;
319 	} else {
320 		dout("%s sent %lu renew after %lu, ignoring\n", __func__,
321 		     monc->sub_renew_sent, monc->sub_renew_after);
322 	}
323 	mutex_unlock(&monc->mutex);
324 	return;
325 bad:
326 	pr_err("got corrupt subscribe-ack msg\n");
327 	ceph_msg_dump(msg);
328 }
329 
330 /*
331  * Register interest in a map
332  *
333  * @sub: one of CEPH_SUB_*
334  * @epoch: X for "every map since X", or 0 for "just the latest"
335  */
336 static bool __ceph_monc_want_map(struct ceph_mon_client *monc, int sub,
337 				 u32 epoch, bool continuous)
338 {
339 	__le64 start = cpu_to_le64(epoch);
340 	u8 flags = !continuous ? CEPH_SUBSCRIBE_ONETIME : 0;
341 
342 	dout("%s %s epoch %u continuous %d\n", __func__, ceph_sub_str[sub],
343 	     epoch, continuous);
344 
345 	if (monc->subs[sub].want &&
346 	    monc->subs[sub].item.start == start &&
347 	    monc->subs[sub].item.flags == flags)
348 		return false;
349 
350 	monc->subs[sub].item.start = start;
351 	monc->subs[sub].item.flags = flags;
352 	monc->subs[sub].want = true;
353 
354 	return true;
355 }
356 
357 bool ceph_monc_want_map(struct ceph_mon_client *monc, int sub, u32 epoch,
358 			bool continuous)
359 {
360 	bool need_request;
361 
362 	mutex_lock(&monc->mutex);
363 	need_request = __ceph_monc_want_map(monc, sub, epoch, continuous);
364 	mutex_unlock(&monc->mutex);
365 
366 	return need_request;
367 }
368 EXPORT_SYMBOL(ceph_monc_want_map);
369 
370 /*
371  * Keep track of which maps we have
372  *
373  * @sub: one of CEPH_SUB_*
374  */
375 static void __ceph_monc_got_map(struct ceph_mon_client *monc, int sub,
376 				u32 epoch)
377 {
378 	dout("%s %s epoch %u\n", __func__, ceph_sub_str[sub], epoch);
379 
380 	if (monc->subs[sub].want) {
381 		if (monc->subs[sub].item.flags & CEPH_SUBSCRIBE_ONETIME)
382 			monc->subs[sub].want = false;
383 		else
384 			monc->subs[sub].item.start = cpu_to_le64(epoch + 1);
385 	}
386 
387 	monc->subs[sub].have = epoch;
388 }
389 
390 void ceph_monc_got_map(struct ceph_mon_client *monc, int sub, u32 epoch)
391 {
392 	mutex_lock(&monc->mutex);
393 	__ceph_monc_got_map(monc, sub, epoch);
394 	mutex_unlock(&monc->mutex);
395 }
396 EXPORT_SYMBOL(ceph_monc_got_map);
397 
398 void ceph_monc_renew_subs(struct ceph_mon_client *monc)
399 {
400 	mutex_lock(&monc->mutex);
401 	__send_subscribe(monc);
402 	mutex_unlock(&monc->mutex);
403 }
404 EXPORT_SYMBOL(ceph_monc_renew_subs);
405 
406 /*
407  * Wait for an osdmap with a given epoch.
408  *
409  * @epoch: epoch to wait for
410  * @timeout: in jiffies, 0 means "wait forever"
411  */
412 int ceph_monc_wait_osdmap(struct ceph_mon_client *monc, u32 epoch,
413 			  unsigned long timeout)
414 {
415 	unsigned long started = jiffies;
416 	long ret;
417 
418 	mutex_lock(&monc->mutex);
419 	while (monc->subs[CEPH_SUB_OSDMAP].have < epoch) {
420 		mutex_unlock(&monc->mutex);
421 
422 		if (timeout && time_after_eq(jiffies, started + timeout))
423 			return -ETIMEDOUT;
424 
425 		ret = wait_event_interruptible_timeout(monc->client->auth_wq,
426 				     monc->subs[CEPH_SUB_OSDMAP].have >= epoch,
427 				     ceph_timeout_jiffies(timeout));
428 		if (ret < 0)
429 			return ret;
430 
431 		mutex_lock(&monc->mutex);
432 	}
433 
434 	mutex_unlock(&monc->mutex);
435 	return 0;
436 }
437 EXPORT_SYMBOL(ceph_monc_wait_osdmap);
438 
439 /*
440  * Open a session with a random monitor.  Request monmap and osdmap,
441  * which are waited upon in __ceph_open_session().
442  */
443 int ceph_monc_open_session(struct ceph_mon_client *monc)
444 {
445 	mutex_lock(&monc->mutex);
446 	__ceph_monc_want_map(monc, CEPH_SUB_MONMAP, 0, true);
447 	__ceph_monc_want_map(monc, CEPH_SUB_OSDMAP, 0, false);
448 	__open_session(monc);
449 	__schedule_delayed(monc);
450 	mutex_unlock(&monc->mutex);
451 	return 0;
452 }
453 EXPORT_SYMBOL(ceph_monc_open_session);
454 
455 static void ceph_monc_handle_map(struct ceph_mon_client *monc,
456 				 struct ceph_msg *msg)
457 {
458 	struct ceph_client *client = monc->client;
459 	struct ceph_monmap *monmap = NULL, *old = monc->monmap;
460 	void *p, *end;
461 
462 	mutex_lock(&monc->mutex);
463 
464 	dout("handle_monmap\n");
465 	p = msg->front.iov_base;
466 	end = p + msg->front.iov_len;
467 
468 	monmap = ceph_monmap_decode(p, end);
469 	if (IS_ERR(monmap)) {
470 		pr_err("problem decoding monmap, %d\n",
471 		       (int)PTR_ERR(monmap));
472 		goto out;
473 	}
474 
475 	if (ceph_check_fsid(monc->client, &monmap->fsid) < 0) {
476 		kfree(monmap);
477 		goto out;
478 	}
479 
480 	client->monc.monmap = monmap;
481 	kfree(old);
482 
483 	__ceph_monc_got_map(monc, CEPH_SUB_MONMAP, monc->monmap->epoch);
484 	client->have_fsid = true;
485 
486 out:
487 	mutex_unlock(&monc->mutex);
488 	wake_up_all(&client->auth_wq);
489 }
490 
491 /*
492  * generic requests (currently statfs, mon_get_version)
493  */
494 DEFINE_RB_FUNCS(generic_request, struct ceph_mon_generic_request, tid, node)
495 
496 static void release_generic_request(struct kref *kref)
497 {
498 	struct ceph_mon_generic_request *req =
499 		container_of(kref, struct ceph_mon_generic_request, kref);
500 
501 	dout("%s greq %p request %p reply %p\n", __func__, req, req->request,
502 	     req->reply);
503 	WARN_ON(!RB_EMPTY_NODE(&req->node));
504 
505 	if (req->reply)
506 		ceph_msg_put(req->reply);
507 	if (req->request)
508 		ceph_msg_put(req->request);
509 
510 	kfree(req);
511 }
512 
513 static void put_generic_request(struct ceph_mon_generic_request *req)
514 {
515 	if (req)
516 		kref_put(&req->kref, release_generic_request);
517 }
518 
519 static void get_generic_request(struct ceph_mon_generic_request *req)
520 {
521 	kref_get(&req->kref);
522 }
523 
524 static struct ceph_mon_generic_request *
525 alloc_generic_request(struct ceph_mon_client *monc, gfp_t gfp)
526 {
527 	struct ceph_mon_generic_request *req;
528 
529 	req = kzalloc(sizeof(*req), gfp);
530 	if (!req)
531 		return NULL;
532 
533 	req->monc = monc;
534 	kref_init(&req->kref);
535 	RB_CLEAR_NODE(&req->node);
536 	init_completion(&req->completion);
537 
538 	dout("%s greq %p\n", __func__, req);
539 	return req;
540 }
541 
542 static void register_generic_request(struct ceph_mon_generic_request *req)
543 {
544 	struct ceph_mon_client *monc = req->monc;
545 
546 	WARN_ON(req->tid);
547 
548 	get_generic_request(req);
549 	req->tid = ++monc->last_tid;
550 	insert_generic_request(&monc->generic_request_tree, req);
551 }
552 
553 static void send_generic_request(struct ceph_mon_client *monc,
554 				 struct ceph_mon_generic_request *req)
555 {
556 	WARN_ON(!req->tid);
557 
558 	dout("%s greq %p tid %llu\n", __func__, req, req->tid);
559 	req->request->hdr.tid = cpu_to_le64(req->tid);
560 	ceph_con_send(&monc->con, ceph_msg_get(req->request));
561 }
562 
563 static void __finish_generic_request(struct ceph_mon_generic_request *req)
564 {
565 	struct ceph_mon_client *monc = req->monc;
566 
567 	dout("%s greq %p tid %llu\n", __func__, req, req->tid);
568 	erase_generic_request(&monc->generic_request_tree, req);
569 
570 	ceph_msg_revoke(req->request);
571 	ceph_msg_revoke_incoming(req->reply);
572 }
573 
574 static void finish_generic_request(struct ceph_mon_generic_request *req)
575 {
576 	__finish_generic_request(req);
577 	put_generic_request(req);
578 }
579 
580 static void complete_generic_request(struct ceph_mon_generic_request *req)
581 {
582 	if (req->complete_cb)
583 		req->complete_cb(req);
584 	else
585 		complete_all(&req->completion);
586 	put_generic_request(req);
587 }
588 
589 static void cancel_generic_request(struct ceph_mon_generic_request *req)
590 {
591 	struct ceph_mon_client *monc = req->monc;
592 	struct ceph_mon_generic_request *lookup_req;
593 
594 	dout("%s greq %p tid %llu\n", __func__, req, req->tid);
595 
596 	mutex_lock(&monc->mutex);
597 	lookup_req = lookup_generic_request(&monc->generic_request_tree,
598 					    req->tid);
599 	if (lookup_req) {
600 		WARN_ON(lookup_req != req);
601 		finish_generic_request(req);
602 	}
603 
604 	mutex_unlock(&monc->mutex);
605 }
606 
607 static int wait_generic_request(struct ceph_mon_generic_request *req)
608 {
609 	int ret;
610 
611 	dout("%s greq %p tid %llu\n", __func__, req, req->tid);
612 	ret = wait_for_completion_interruptible(&req->completion);
613 	if (ret)
614 		cancel_generic_request(req);
615 	else
616 		ret = req->result; /* completed */
617 
618 	return ret;
619 }
620 
621 static struct ceph_msg *get_generic_reply(struct ceph_connection *con,
622 					 struct ceph_msg_header *hdr,
623 					 int *skip)
624 {
625 	struct ceph_mon_client *monc = con->private;
626 	struct ceph_mon_generic_request *req;
627 	u64 tid = le64_to_cpu(hdr->tid);
628 	struct ceph_msg *m;
629 
630 	mutex_lock(&monc->mutex);
631 	req = lookup_generic_request(&monc->generic_request_tree, tid);
632 	if (!req) {
633 		dout("get_generic_reply %lld dne\n", tid);
634 		*skip = 1;
635 		m = NULL;
636 	} else {
637 		dout("get_generic_reply %lld got %p\n", tid, req->reply);
638 		*skip = 0;
639 		m = ceph_msg_get(req->reply);
640 		/*
641 		 * we don't need to track the connection reading into
642 		 * this reply because we only have one open connection
643 		 * at a time, ever.
644 		 */
645 	}
646 	mutex_unlock(&monc->mutex);
647 	return m;
648 }
649 
650 /*
651  * statfs
652  */
653 static void handle_statfs_reply(struct ceph_mon_client *monc,
654 				struct ceph_msg *msg)
655 {
656 	struct ceph_mon_generic_request *req;
657 	struct ceph_mon_statfs_reply *reply = msg->front.iov_base;
658 	u64 tid = le64_to_cpu(msg->hdr.tid);
659 
660 	dout("%s msg %p tid %llu\n", __func__, msg, tid);
661 
662 	if (msg->front.iov_len != sizeof(*reply))
663 		goto bad;
664 
665 	mutex_lock(&monc->mutex);
666 	req = lookup_generic_request(&monc->generic_request_tree, tid);
667 	if (!req) {
668 		mutex_unlock(&monc->mutex);
669 		return;
670 	}
671 
672 	req->result = 0;
673 	*req->u.st = reply->st; /* struct */
674 	__finish_generic_request(req);
675 	mutex_unlock(&monc->mutex);
676 
677 	complete_generic_request(req);
678 	return;
679 
680 bad:
681 	pr_err("corrupt statfs reply, tid %llu\n", tid);
682 	ceph_msg_dump(msg);
683 }
684 
685 /*
686  * Do a synchronous statfs().
687  */
688 int ceph_monc_do_statfs(struct ceph_mon_client *monc, u64 data_pool,
689 			struct ceph_statfs *buf)
690 {
691 	struct ceph_mon_generic_request *req;
692 	struct ceph_mon_statfs *h;
693 	int ret = -ENOMEM;
694 
695 	req = alloc_generic_request(monc, GFP_NOFS);
696 	if (!req)
697 		goto out;
698 
699 	req->request = ceph_msg_new(CEPH_MSG_STATFS, sizeof(*h), GFP_NOFS,
700 				    true);
701 	if (!req->request)
702 		goto out;
703 
704 	req->reply = ceph_msg_new(CEPH_MSG_STATFS_REPLY, 64, GFP_NOFS, true);
705 	if (!req->reply)
706 		goto out;
707 
708 	req->u.st = buf;
709 	req->request->hdr.version = cpu_to_le16(2);
710 
711 	mutex_lock(&monc->mutex);
712 	register_generic_request(req);
713 	/* fill out request */
714 	h = req->request->front.iov_base;
715 	h->monhdr.have_version = 0;
716 	h->monhdr.session_mon = cpu_to_le16(-1);
717 	h->monhdr.session_mon_tid = 0;
718 	h->fsid = monc->monmap->fsid;
719 	h->contains_data_pool = (data_pool != CEPH_NOPOOL);
720 	h->data_pool = cpu_to_le64(data_pool);
721 	send_generic_request(monc, req);
722 	mutex_unlock(&monc->mutex);
723 
724 	ret = wait_generic_request(req);
725 out:
726 	put_generic_request(req);
727 	return ret;
728 }
729 EXPORT_SYMBOL(ceph_monc_do_statfs);
730 
731 static void handle_get_version_reply(struct ceph_mon_client *monc,
732 				     struct ceph_msg *msg)
733 {
734 	struct ceph_mon_generic_request *req;
735 	u64 tid = le64_to_cpu(msg->hdr.tid);
736 	void *p = msg->front.iov_base;
737 	void *end = p + msg->front_alloc_len;
738 	u64 handle;
739 
740 	dout("%s msg %p tid %llu\n", __func__, msg, tid);
741 
742 	ceph_decode_need(&p, end, 2*sizeof(u64), bad);
743 	handle = ceph_decode_64(&p);
744 	if (tid != 0 && tid != handle)
745 		goto bad;
746 
747 	mutex_lock(&monc->mutex);
748 	req = lookup_generic_request(&monc->generic_request_tree, handle);
749 	if (!req) {
750 		mutex_unlock(&monc->mutex);
751 		return;
752 	}
753 
754 	req->result = 0;
755 	req->u.newest = ceph_decode_64(&p);
756 	__finish_generic_request(req);
757 	mutex_unlock(&monc->mutex);
758 
759 	complete_generic_request(req);
760 	return;
761 
762 bad:
763 	pr_err("corrupt mon_get_version reply, tid %llu\n", tid);
764 	ceph_msg_dump(msg);
765 }
766 
767 static struct ceph_mon_generic_request *
768 __ceph_monc_get_version(struct ceph_mon_client *monc, const char *what,
769 			ceph_monc_callback_t cb, u64 private_data)
770 {
771 	struct ceph_mon_generic_request *req;
772 
773 	req = alloc_generic_request(monc, GFP_NOIO);
774 	if (!req)
775 		goto err_put_req;
776 
777 	req->request = ceph_msg_new(CEPH_MSG_MON_GET_VERSION,
778 				    sizeof(u64) + sizeof(u32) + strlen(what),
779 				    GFP_NOIO, true);
780 	if (!req->request)
781 		goto err_put_req;
782 
783 	req->reply = ceph_msg_new(CEPH_MSG_MON_GET_VERSION_REPLY, 32, GFP_NOIO,
784 				  true);
785 	if (!req->reply)
786 		goto err_put_req;
787 
788 	req->complete_cb = cb;
789 	req->private_data = private_data;
790 
791 	mutex_lock(&monc->mutex);
792 	register_generic_request(req);
793 	{
794 		void *p = req->request->front.iov_base;
795 		void *const end = p + req->request->front_alloc_len;
796 
797 		ceph_encode_64(&p, req->tid); /* handle */
798 		ceph_encode_string(&p, end, what, strlen(what));
799 		WARN_ON(p != end);
800 	}
801 	send_generic_request(monc, req);
802 	mutex_unlock(&monc->mutex);
803 
804 	return req;
805 
806 err_put_req:
807 	put_generic_request(req);
808 	return ERR_PTR(-ENOMEM);
809 }
810 
811 /*
812  * Send MMonGetVersion and wait for the reply.
813  *
814  * @what: one of "mdsmap", "osdmap" or "monmap"
815  */
816 int ceph_monc_get_version(struct ceph_mon_client *monc, const char *what,
817 			  u64 *newest)
818 {
819 	struct ceph_mon_generic_request *req;
820 	int ret;
821 
822 	req = __ceph_monc_get_version(monc, what, NULL, 0);
823 	if (IS_ERR(req))
824 		return PTR_ERR(req);
825 
826 	ret = wait_generic_request(req);
827 	if (!ret)
828 		*newest = req->u.newest;
829 
830 	put_generic_request(req);
831 	return ret;
832 }
833 EXPORT_SYMBOL(ceph_monc_get_version);
834 
835 /*
836  * Send MMonGetVersion,
837  *
838  * @what: one of "mdsmap", "osdmap" or "monmap"
839  */
840 int ceph_monc_get_version_async(struct ceph_mon_client *monc, const char *what,
841 				ceph_monc_callback_t cb, u64 private_data)
842 {
843 	struct ceph_mon_generic_request *req;
844 
845 	req = __ceph_monc_get_version(monc, what, cb, private_data);
846 	if (IS_ERR(req))
847 		return PTR_ERR(req);
848 
849 	put_generic_request(req);
850 	return 0;
851 }
852 EXPORT_SYMBOL(ceph_monc_get_version_async);
853 
854 static void handle_command_ack(struct ceph_mon_client *monc,
855 			       struct ceph_msg *msg)
856 {
857 	struct ceph_mon_generic_request *req;
858 	void *p = msg->front.iov_base;
859 	void *const end = p + msg->front_alloc_len;
860 	u64 tid = le64_to_cpu(msg->hdr.tid);
861 
862 	dout("%s msg %p tid %llu\n", __func__, msg, tid);
863 
864 	ceph_decode_need(&p, end, sizeof(struct ceph_mon_request_header) +
865 							    sizeof(u32), bad);
866 	p += sizeof(struct ceph_mon_request_header);
867 
868 	mutex_lock(&monc->mutex);
869 	req = lookup_generic_request(&monc->generic_request_tree, tid);
870 	if (!req) {
871 		mutex_unlock(&monc->mutex);
872 		return;
873 	}
874 
875 	req->result = ceph_decode_32(&p);
876 	__finish_generic_request(req);
877 	mutex_unlock(&monc->mutex);
878 
879 	complete_generic_request(req);
880 	return;
881 
882 bad:
883 	pr_err("corrupt mon_command ack, tid %llu\n", tid);
884 	ceph_msg_dump(msg);
885 }
886 
887 int ceph_monc_blacklist_add(struct ceph_mon_client *monc,
888 			    struct ceph_entity_addr *client_addr)
889 {
890 	struct ceph_mon_generic_request *req;
891 	struct ceph_mon_command *h;
892 	int ret = -ENOMEM;
893 	int len;
894 
895 	req = alloc_generic_request(monc, GFP_NOIO);
896 	if (!req)
897 		goto out;
898 
899 	req->request = ceph_msg_new(CEPH_MSG_MON_COMMAND, 256, GFP_NOIO, true);
900 	if (!req->request)
901 		goto out;
902 
903 	req->reply = ceph_msg_new(CEPH_MSG_MON_COMMAND_ACK, 512, GFP_NOIO,
904 				  true);
905 	if (!req->reply)
906 		goto out;
907 
908 	mutex_lock(&monc->mutex);
909 	register_generic_request(req);
910 	h = req->request->front.iov_base;
911 	h->monhdr.have_version = 0;
912 	h->monhdr.session_mon = cpu_to_le16(-1);
913 	h->monhdr.session_mon_tid = 0;
914 	h->fsid = monc->monmap->fsid;
915 	h->num_strs = cpu_to_le32(1);
916 	len = sprintf(h->str, "{ \"prefix\": \"osd blacklist\", \
917 		                 \"blacklistop\": \"add\", \
918 				 \"addr\": \"%pISpc/%u\" }",
919 		      &client_addr->in_addr, le32_to_cpu(client_addr->nonce));
920 	h->str_len = cpu_to_le32(len);
921 	send_generic_request(monc, req);
922 	mutex_unlock(&monc->mutex);
923 
924 	ret = wait_generic_request(req);
925 	if (!ret)
926 		/*
927 		 * Make sure we have the osdmap that includes the blacklist
928 		 * entry.  This is needed to ensure that the OSDs pick up the
929 		 * new blacklist before processing any future requests from
930 		 * this client.
931 		 */
932 		ret = ceph_wait_for_latest_osdmap(monc->client, 0);
933 
934 out:
935 	put_generic_request(req);
936 	return ret;
937 }
938 EXPORT_SYMBOL(ceph_monc_blacklist_add);
939 
940 /*
941  * Resend pending generic requests.
942  */
943 static void __resend_generic_request(struct ceph_mon_client *monc)
944 {
945 	struct ceph_mon_generic_request *req;
946 	struct rb_node *p;
947 
948 	for (p = rb_first(&monc->generic_request_tree); p; p = rb_next(p)) {
949 		req = rb_entry(p, struct ceph_mon_generic_request, node);
950 		ceph_msg_revoke(req->request);
951 		ceph_msg_revoke_incoming(req->reply);
952 		ceph_con_send(&monc->con, ceph_msg_get(req->request));
953 	}
954 }
955 
956 /*
957  * Delayed work.  If we haven't mounted yet, retry.  Otherwise,
958  * renew/retry subscription as needed (in case it is timing out, or we
959  * got an ENOMEM).  And keep the monitor connection alive.
960  */
961 static void delayed_work(struct work_struct *work)
962 {
963 	struct ceph_mon_client *monc =
964 		container_of(work, struct ceph_mon_client, delayed_work.work);
965 
966 	dout("monc delayed_work\n");
967 	mutex_lock(&monc->mutex);
968 	if (monc->hunting) {
969 		dout("%s continuing hunt\n", __func__);
970 		reopen_session(monc);
971 	} else {
972 		int is_auth = ceph_auth_is_authenticated(monc->auth);
973 		if (ceph_con_keepalive_expired(&monc->con,
974 					       CEPH_MONC_PING_TIMEOUT)) {
975 			dout("monc keepalive timeout\n");
976 			is_auth = 0;
977 			reopen_session(monc);
978 		}
979 
980 		if (!monc->hunting) {
981 			ceph_con_keepalive(&monc->con);
982 			__validate_auth(monc);
983 			un_backoff(monc);
984 		}
985 
986 		if (is_auth &&
987 		    !(monc->con.peer_features & CEPH_FEATURE_MON_STATEFUL_SUB)) {
988 			unsigned long now = jiffies;
989 
990 			dout("%s renew subs? now %lu renew after %lu\n",
991 			     __func__, now, monc->sub_renew_after);
992 			if (time_after_eq(now, monc->sub_renew_after))
993 				__send_subscribe(monc);
994 		}
995 	}
996 	__schedule_delayed(monc);
997 	mutex_unlock(&monc->mutex);
998 }
999 
1000 /*
1001  * On startup, we build a temporary monmap populated with the IPs
1002  * provided by mount(2).
1003  */
1004 static int build_initial_monmap(struct ceph_mon_client *monc)
1005 {
1006 	struct ceph_options *opt = monc->client->options;
1007 	struct ceph_entity_addr *mon_addr = opt->mon_addr;
1008 	int num_mon = opt->num_mon;
1009 	int i;
1010 
1011 	/* build initial monmap */
1012 	monc->monmap = kzalloc(struct_size(monc->monmap, mon_inst, num_mon),
1013 			       GFP_KERNEL);
1014 	if (!monc->monmap)
1015 		return -ENOMEM;
1016 	for (i = 0; i < num_mon; i++) {
1017 		monc->monmap->mon_inst[i].addr = mon_addr[i];
1018 		monc->monmap->mon_inst[i].addr.nonce = 0;
1019 		monc->monmap->mon_inst[i].name.type =
1020 			CEPH_ENTITY_TYPE_MON;
1021 		monc->monmap->mon_inst[i].name.num = cpu_to_le64(i);
1022 	}
1023 	monc->monmap->num_mon = num_mon;
1024 	return 0;
1025 }
1026 
1027 int ceph_monc_init(struct ceph_mon_client *monc, struct ceph_client *cl)
1028 {
1029 	int err = 0;
1030 
1031 	dout("init\n");
1032 	memset(monc, 0, sizeof(*monc));
1033 	monc->client = cl;
1034 	monc->monmap = NULL;
1035 	mutex_init(&monc->mutex);
1036 
1037 	err = build_initial_monmap(monc);
1038 	if (err)
1039 		goto out;
1040 
1041 	/* connection */
1042 	/* authentication */
1043 	monc->auth = ceph_auth_init(cl->options->name,
1044 				    cl->options->key);
1045 	if (IS_ERR(monc->auth)) {
1046 		err = PTR_ERR(monc->auth);
1047 		goto out_monmap;
1048 	}
1049 	monc->auth->want_keys =
1050 		CEPH_ENTITY_TYPE_AUTH | CEPH_ENTITY_TYPE_MON |
1051 		CEPH_ENTITY_TYPE_OSD | CEPH_ENTITY_TYPE_MDS;
1052 
1053 	/* msgs */
1054 	err = -ENOMEM;
1055 	monc->m_subscribe_ack = ceph_msg_new(CEPH_MSG_MON_SUBSCRIBE_ACK,
1056 				     sizeof(struct ceph_mon_subscribe_ack),
1057 				     GFP_KERNEL, true);
1058 	if (!monc->m_subscribe_ack)
1059 		goto out_auth;
1060 
1061 	monc->m_subscribe = ceph_msg_new(CEPH_MSG_MON_SUBSCRIBE, 128,
1062 					 GFP_KERNEL, true);
1063 	if (!monc->m_subscribe)
1064 		goto out_subscribe_ack;
1065 
1066 	monc->m_auth_reply = ceph_msg_new(CEPH_MSG_AUTH_REPLY, 4096,
1067 					  GFP_KERNEL, true);
1068 	if (!monc->m_auth_reply)
1069 		goto out_subscribe;
1070 
1071 	monc->m_auth = ceph_msg_new(CEPH_MSG_AUTH, 4096, GFP_KERNEL, true);
1072 	monc->pending_auth = 0;
1073 	if (!monc->m_auth)
1074 		goto out_auth_reply;
1075 
1076 	ceph_con_init(&monc->con, monc, &mon_con_ops,
1077 		      &monc->client->msgr);
1078 
1079 	monc->cur_mon = -1;
1080 	monc->had_a_connection = false;
1081 	monc->hunt_mult = 1;
1082 
1083 	INIT_DELAYED_WORK(&monc->delayed_work, delayed_work);
1084 	monc->generic_request_tree = RB_ROOT;
1085 	monc->last_tid = 0;
1086 
1087 	monc->fs_cluster_id = CEPH_FS_CLUSTER_ID_NONE;
1088 
1089 	return 0;
1090 
1091 out_auth_reply:
1092 	ceph_msg_put(monc->m_auth_reply);
1093 out_subscribe:
1094 	ceph_msg_put(monc->m_subscribe);
1095 out_subscribe_ack:
1096 	ceph_msg_put(monc->m_subscribe_ack);
1097 out_auth:
1098 	ceph_auth_destroy(monc->auth);
1099 out_monmap:
1100 	kfree(monc->monmap);
1101 out:
1102 	return err;
1103 }
1104 EXPORT_SYMBOL(ceph_monc_init);
1105 
1106 void ceph_monc_stop(struct ceph_mon_client *monc)
1107 {
1108 	dout("stop\n");
1109 	cancel_delayed_work_sync(&monc->delayed_work);
1110 
1111 	mutex_lock(&monc->mutex);
1112 	__close_session(monc);
1113 	monc->cur_mon = -1;
1114 	mutex_unlock(&monc->mutex);
1115 
1116 	/*
1117 	 * flush msgr queue before we destroy ourselves to ensure that:
1118 	 *  - any work that references our embedded con is finished.
1119 	 *  - any osd_client or other work that may reference an authorizer
1120 	 *    finishes before we shut down the auth subsystem.
1121 	 */
1122 	ceph_msgr_flush();
1123 
1124 	ceph_auth_destroy(monc->auth);
1125 
1126 	WARN_ON(!RB_EMPTY_ROOT(&monc->generic_request_tree));
1127 
1128 	ceph_msg_put(monc->m_auth);
1129 	ceph_msg_put(monc->m_auth_reply);
1130 	ceph_msg_put(monc->m_subscribe);
1131 	ceph_msg_put(monc->m_subscribe_ack);
1132 
1133 	kfree(monc->monmap);
1134 }
1135 EXPORT_SYMBOL(ceph_monc_stop);
1136 
1137 static void finish_hunting(struct ceph_mon_client *monc)
1138 {
1139 	if (monc->hunting) {
1140 		dout("%s found mon%d\n", __func__, monc->cur_mon);
1141 		monc->hunting = false;
1142 		monc->had_a_connection = true;
1143 		un_backoff(monc);
1144 		__schedule_delayed(monc);
1145 	}
1146 }
1147 
1148 static void handle_auth_reply(struct ceph_mon_client *monc,
1149 			      struct ceph_msg *msg)
1150 {
1151 	int ret;
1152 	int was_auth = 0;
1153 
1154 	mutex_lock(&monc->mutex);
1155 	was_auth = ceph_auth_is_authenticated(monc->auth);
1156 	monc->pending_auth = 0;
1157 	ret = ceph_handle_auth_reply(monc->auth, msg->front.iov_base,
1158 				     msg->front.iov_len,
1159 				     monc->m_auth->front.iov_base,
1160 				     monc->m_auth->front_alloc_len);
1161 	if (ret > 0) {
1162 		__send_prepared_auth_request(monc, ret);
1163 		goto out;
1164 	}
1165 
1166 	finish_hunting(monc);
1167 
1168 	if (ret < 0) {
1169 		monc->client->auth_err = ret;
1170 	} else if (!was_auth && ceph_auth_is_authenticated(monc->auth)) {
1171 		dout("authenticated, starting session\n");
1172 
1173 		monc->client->msgr.inst.name.type = CEPH_ENTITY_TYPE_CLIENT;
1174 		monc->client->msgr.inst.name.num =
1175 					cpu_to_le64(monc->auth->global_id);
1176 
1177 		__send_subscribe(monc);
1178 		__resend_generic_request(monc);
1179 
1180 		pr_info("mon%d %s session established\n", monc->cur_mon,
1181 			ceph_pr_addr(&monc->con.peer_addr.in_addr));
1182 	}
1183 
1184 out:
1185 	mutex_unlock(&monc->mutex);
1186 	if (monc->client->auth_err < 0)
1187 		wake_up_all(&monc->client->auth_wq);
1188 }
1189 
1190 static int __validate_auth(struct ceph_mon_client *monc)
1191 {
1192 	int ret;
1193 
1194 	if (monc->pending_auth)
1195 		return 0;
1196 
1197 	ret = ceph_build_auth(monc->auth, monc->m_auth->front.iov_base,
1198 			      monc->m_auth->front_alloc_len);
1199 	if (ret <= 0)
1200 		return ret; /* either an error, or no need to authenticate */
1201 	__send_prepared_auth_request(monc, ret);
1202 	return 0;
1203 }
1204 
1205 int ceph_monc_validate_auth(struct ceph_mon_client *monc)
1206 {
1207 	int ret;
1208 
1209 	mutex_lock(&monc->mutex);
1210 	ret = __validate_auth(monc);
1211 	mutex_unlock(&monc->mutex);
1212 	return ret;
1213 }
1214 EXPORT_SYMBOL(ceph_monc_validate_auth);
1215 
1216 /*
1217  * handle incoming message
1218  */
1219 static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
1220 {
1221 	struct ceph_mon_client *monc = con->private;
1222 	int type = le16_to_cpu(msg->hdr.type);
1223 
1224 	if (!monc)
1225 		return;
1226 
1227 	switch (type) {
1228 	case CEPH_MSG_AUTH_REPLY:
1229 		handle_auth_reply(monc, msg);
1230 		break;
1231 
1232 	case CEPH_MSG_MON_SUBSCRIBE_ACK:
1233 		handle_subscribe_ack(monc, msg);
1234 		break;
1235 
1236 	case CEPH_MSG_STATFS_REPLY:
1237 		handle_statfs_reply(monc, msg);
1238 		break;
1239 
1240 	case CEPH_MSG_MON_GET_VERSION_REPLY:
1241 		handle_get_version_reply(monc, msg);
1242 		break;
1243 
1244 	case CEPH_MSG_MON_COMMAND_ACK:
1245 		handle_command_ack(monc, msg);
1246 		break;
1247 
1248 	case CEPH_MSG_MON_MAP:
1249 		ceph_monc_handle_map(monc, msg);
1250 		break;
1251 
1252 	case CEPH_MSG_OSD_MAP:
1253 		ceph_osdc_handle_map(&monc->client->osdc, msg);
1254 		break;
1255 
1256 	default:
1257 		/* can the chained handler handle it? */
1258 		if (monc->client->extra_mon_dispatch &&
1259 		    monc->client->extra_mon_dispatch(monc->client, msg) == 0)
1260 			break;
1261 
1262 		pr_err("received unknown message type %d %s\n", type,
1263 		       ceph_msg_type_name(type));
1264 	}
1265 	ceph_msg_put(msg);
1266 }
1267 
1268 /*
1269  * Allocate memory for incoming message
1270  */
1271 static struct ceph_msg *mon_alloc_msg(struct ceph_connection *con,
1272 				      struct ceph_msg_header *hdr,
1273 				      int *skip)
1274 {
1275 	struct ceph_mon_client *monc = con->private;
1276 	int type = le16_to_cpu(hdr->type);
1277 	int front_len = le32_to_cpu(hdr->front_len);
1278 	struct ceph_msg *m = NULL;
1279 
1280 	*skip = 0;
1281 
1282 	switch (type) {
1283 	case CEPH_MSG_MON_SUBSCRIBE_ACK:
1284 		m = ceph_msg_get(monc->m_subscribe_ack);
1285 		break;
1286 	case CEPH_MSG_STATFS_REPLY:
1287 	case CEPH_MSG_MON_COMMAND_ACK:
1288 		return get_generic_reply(con, hdr, skip);
1289 	case CEPH_MSG_AUTH_REPLY:
1290 		m = ceph_msg_get(monc->m_auth_reply);
1291 		break;
1292 	case CEPH_MSG_MON_GET_VERSION_REPLY:
1293 		if (le64_to_cpu(hdr->tid) != 0)
1294 			return get_generic_reply(con, hdr, skip);
1295 
1296 		/*
1297 		 * Older OSDs don't set reply tid even if the orignal
1298 		 * request had a non-zero tid.  Work around this weirdness
1299 		 * by allocating a new message.
1300 		 */
1301 		/* fall through */
1302 	case CEPH_MSG_MON_MAP:
1303 	case CEPH_MSG_MDS_MAP:
1304 	case CEPH_MSG_OSD_MAP:
1305 	case CEPH_MSG_FS_MAP_USER:
1306 		m = ceph_msg_new(type, front_len, GFP_NOFS, false);
1307 		if (!m)
1308 			return NULL;	/* ENOMEM--return skip == 0 */
1309 		break;
1310 	}
1311 
1312 	if (!m) {
1313 		pr_info("alloc_msg unknown type %d\n", type);
1314 		*skip = 1;
1315 	} else if (front_len > m->front_alloc_len) {
1316 		pr_warn("mon_alloc_msg front %d > prealloc %d (%u#%llu)\n",
1317 			front_len, m->front_alloc_len,
1318 			(unsigned int)con->peer_name.type,
1319 			le64_to_cpu(con->peer_name.num));
1320 		ceph_msg_put(m);
1321 		m = ceph_msg_new(type, front_len, GFP_NOFS, false);
1322 	}
1323 
1324 	return m;
1325 }
1326 
1327 /*
1328  * If the monitor connection resets, pick a new monitor and resubmit
1329  * any pending requests.
1330  */
1331 static void mon_fault(struct ceph_connection *con)
1332 {
1333 	struct ceph_mon_client *monc = con->private;
1334 
1335 	mutex_lock(&monc->mutex);
1336 	dout("%s mon%d\n", __func__, monc->cur_mon);
1337 	if (monc->cur_mon >= 0) {
1338 		if (!monc->hunting) {
1339 			dout("%s hunting for new mon\n", __func__);
1340 			reopen_session(monc);
1341 			__schedule_delayed(monc);
1342 		} else {
1343 			dout("%s already hunting\n", __func__);
1344 		}
1345 	}
1346 	mutex_unlock(&monc->mutex);
1347 }
1348 
1349 /*
1350  * We can ignore refcounting on the connection struct, as all references
1351  * will come from the messenger workqueue, which is drained prior to
1352  * mon_client destruction.
1353  */
1354 static struct ceph_connection *con_get(struct ceph_connection *con)
1355 {
1356 	return con;
1357 }
1358 
1359 static void con_put(struct ceph_connection *con)
1360 {
1361 }
1362 
1363 static const struct ceph_connection_operations mon_con_ops = {
1364 	.get = con_get,
1365 	.put = con_put,
1366 	.dispatch = dispatch,
1367 	.fault = mon_fault,
1368 	.alloc_msg = mon_alloc_msg,
1369 };
1370