xref: /freebsd/sbin/hastd/secondary.c (revision a3cf0ef5a295c885c895fabfd56470c0d1db322d)
1 /*-
2  * Copyright (c) 2009-2010 The FreeBSD Foundation
3  * Copyright (c) 2010 Pawel Jakub Dawidek <pjd@FreeBSD.org>
4  * All rights reserved.
5  *
6  * This software was developed by Pawel Jakub Dawidek under sponsorship from
7  * the FreeBSD Foundation.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/param.h>
35 #include <sys/time.h>
36 #include <sys/bio.h>
37 #include <sys/disk.h>
38 #include <sys/stat.h>
39 
40 #include <assert.h>
41 #include <err.h>
42 #include <errno.h>
43 #include <fcntl.h>
44 #include <libgeom.h>
45 #include <pthread.h>
46 #include <signal.h>
47 #include <stdint.h>
48 #include <stdio.h>
49 #include <string.h>
50 #include <sysexits.h>
51 #include <unistd.h>
52 
53 #include <activemap.h>
54 #include <nv.h>
55 #include <pjdlog.h>
56 
57 #include "control.h"
58 #include "event.h"
59 #include "hast.h"
60 #include "hast_proto.h"
61 #include "hastd.h"
62 #include "hooks.h"
63 #include "metadata.h"
64 #include "proto.h"
65 #include "subr.h"
66 #include "synch.h"
67 
68 struct hio {
69 	uint64_t 	 hio_seq;
70 	int	 	 hio_error;
71 	struct nv	*hio_nv;
72 	void		*hio_data;
73 	uint8_t		 hio_cmd;
74 	uint64_t	 hio_offset;
75 	uint64_t	 hio_length;
76 	TAILQ_ENTRY(hio) hio_next;
77 };
78 
79 static struct hast_resource *gres;
80 
81 /*
82  * Free list holds unused structures. When free list is empty, we have to wait
83  * until some in-progress requests are freed.
84  */
85 static TAILQ_HEAD(, hio) hio_free_list;
86 static pthread_mutex_t hio_free_list_lock;
87 static pthread_cond_t hio_free_list_cond;
88 /*
89  * Disk thread (the one that do I/O requests) takes requests from this list.
90  */
91 static TAILQ_HEAD(, hio) hio_disk_list;
92 static pthread_mutex_t hio_disk_list_lock;
93 static pthread_cond_t hio_disk_list_cond;
94 /*
95  * There is one recv list for every component, although local components don't
96  * use recv lists as local requests are done synchronously.
97  */
98 static TAILQ_HEAD(, hio) hio_send_list;
99 static pthread_mutex_t hio_send_list_lock;
100 static pthread_cond_t hio_send_list_cond;
101 
102 /*
103  * Maximum number of outstanding I/O requests.
104  */
105 #define	HAST_HIO_MAX	256
106 
107 static void *recv_thread(void *arg);
108 static void *disk_thread(void *arg);
109 static void *send_thread(void *arg);
110 
111 #define	QUEUE_INSERT(name, hio)	do {					\
112 	bool _wakeup;							\
113 									\
114 	mtx_lock(&hio_##name##_list_lock);				\
115 	_wakeup = TAILQ_EMPTY(&hio_##name##_list);			\
116 	TAILQ_INSERT_TAIL(&hio_##name##_list, (hio), hio_next);		\
117 	mtx_unlock(&hio_##name##_list_lock);				\
118 	if (_wakeup)							\
119 		cv_signal(&hio_##name##_list_cond);			\
120 } while (0)
121 #define	QUEUE_TAKE(name, hio)	do {					\
122 	mtx_lock(&hio_##name##_list_lock);				\
123 	while (((hio) = TAILQ_FIRST(&hio_##name##_list)) == NULL) {	\
124 		cv_wait(&hio_##name##_list_cond,			\
125 		    &hio_##name##_list_lock);				\
126 	}								\
127 	TAILQ_REMOVE(&hio_##name##_list, (hio), hio_next);		\
128 	mtx_unlock(&hio_##name##_list_lock);				\
129 } while (0)
130 
131 static void
132 init_environment(void)
133 {
134 	struct hio *hio;
135 	unsigned int ii;
136 
137 	/*
138 	 * Initialize lists, their locks and theirs condition variables.
139 	 */
140 	TAILQ_INIT(&hio_free_list);
141 	mtx_init(&hio_free_list_lock);
142 	cv_init(&hio_free_list_cond);
143 	TAILQ_INIT(&hio_disk_list);
144 	mtx_init(&hio_disk_list_lock);
145 	cv_init(&hio_disk_list_cond);
146 	TAILQ_INIT(&hio_send_list);
147 	mtx_init(&hio_send_list_lock);
148 	cv_init(&hio_send_list_cond);
149 
150 	/*
151 	 * Allocate requests pool and initialize requests.
152 	 */
153 	for (ii = 0; ii < HAST_HIO_MAX; ii++) {
154 		hio = malloc(sizeof(*hio));
155 		if (hio == NULL) {
156 			pjdlog_exitx(EX_TEMPFAIL,
157 			    "Unable to allocate memory (%zu bytes) for hio request.",
158 			    sizeof(*hio));
159 		}
160 		hio->hio_error = 0;
161 		hio->hio_data = malloc(MAXPHYS);
162 		if (hio->hio_data == NULL) {
163 			pjdlog_exitx(EX_TEMPFAIL,
164 			    "Unable to allocate memory (%zu bytes) for gctl_data.",
165 			    (size_t)MAXPHYS);
166 		}
167 		TAILQ_INSERT_HEAD(&hio_free_list, hio, hio_next);
168 	}
169 }
170 
171 static void
172 init_local(struct hast_resource *res)
173 {
174 
175 	if (metadata_read(res, true) < 0)
176 		exit(EX_NOINPUT);
177 }
178 
179 static void
180 init_remote(struct hast_resource *res, struct nv *nvin)
181 {
182 	uint64_t resuid;
183 	struct nv *nvout;
184 	unsigned char *map;
185 	size_t mapsize;
186 
187 	map = NULL;
188 	mapsize = 0;
189 	nvout = nv_alloc();
190 	nv_add_int64(nvout, (int64_t)res->hr_datasize, "datasize");
191 	nv_add_int32(nvout, (int32_t)res->hr_extentsize, "extentsize");
192 	resuid = nv_get_uint64(nvin, "resuid");
193 	res->hr_primary_localcnt = nv_get_uint64(nvin, "localcnt");
194 	res->hr_primary_remotecnt = nv_get_uint64(nvin, "remotecnt");
195 	nv_add_uint64(nvout, res->hr_secondary_localcnt, "localcnt");
196 	nv_add_uint64(nvout, res->hr_secondary_remotecnt, "remotecnt");
197 	mapsize = activemap_calc_ondisk_size(res->hr_local_mediasize -
198 	    METADATA_SIZE, res->hr_extentsize, res->hr_local_sectorsize);
199 	map = malloc(mapsize);
200 	if (map == NULL) {
201 		pjdlog_exitx(EX_TEMPFAIL,
202 		    "Unable to allocate memory (%zu bytes) for activemap.",
203 		    mapsize);
204 	}
205 	nv_add_uint32(nvout, (uint32_t)mapsize, "mapsize");
206 	/*
207 	 * When we work as primary and secondary is missing we will increase
208 	 * localcnt in our metadata. When secondary is connected and synced
209 	 * we make localcnt be equal to remotecnt, which means nodes are more
210 	 * or less in sync.
211 	 * Split-brain condition is when both nodes are not able to communicate
212 	 * and are both configured as primary nodes. In turn, they can both
213 	 * make incompatible changes to the data and we have to detect that.
214 	 * Under split-brain condition we will increase our localcnt on first
215 	 * write and remote node will increase its localcnt on first write.
216 	 * When we connect we can see that primary's localcnt is greater than
217 	 * our remotecnt (primary was modified while we weren't watching) and
218 	 * our localcnt is greater than primary's remotecnt (we were modified
219 	 * while primary wasn't watching).
220 	 * There are many possible combinations which are all gathered below.
221 	 * Don't pay too much attention to exact numbers, the more important
222 	 * is to compare them. We compare secondary's local with primary's
223 	 * remote and secondary's remote with primary's local.
224 	 * Note that every case where primary's localcnt is smaller than
225 	 * secondary's remotecnt and where secondary's localcnt is smaller than
226 	 * primary's remotecnt should be impossible in practise. We will perform
227 	 * full synchronization then. Those cases are marked with an asterisk.
228 	 * Regular synchronization means that only extents marked as dirty are
229 	 * synchronized (regular synchronization).
230 	 *
231 	 * SECONDARY METADATA PRIMARY METADATA
232 	 * local=3 remote=3   local=2 remote=2*  ?! Full sync from secondary.
233 	 * local=3 remote=3   local=2 remote=3*  ?! Full sync from primary.
234 	 * local=3 remote=3   local=2 remote=4*  ?! Full sync from primary.
235 	 * local=3 remote=3   local=3 remote=2   Primary is out-of-date,
236 	 *                                       regular sync from secondary.
237 	 * local=3 remote=3   local=3 remote=3   Regular sync just in case.
238 	 * local=3 remote=3   local=3 remote=4*  ?! Full sync from primary.
239 	 * local=3 remote=3   local=4 remote=2   Split-brain condition.
240 	 * local=3 remote=3   local=4 remote=3   Secondary out-of-date,
241 	 *                                       regular sync from primary.
242 	 * local=3 remote=3   local=4 remote=4*  ?! Full sync from primary.
243 	 */
244 	if (res->hr_resuid == 0) {
245 		/*
246 		 * Provider is used for the first time. If primary node done no
247 		 * writes yet as well (we will find "virgin" argument) then
248 		 * there is no need to synchronize anything. If primary node
249 		 * done any writes already we have to synchronize everything.
250 		 */
251 		assert(res->hr_secondary_localcnt == 0);
252 		res->hr_resuid = resuid;
253 		if (metadata_write(res) < 0)
254 			exit(EX_NOINPUT);
255 		if (nv_exists(nvin, "virgin")) {
256 			free(map);
257 			map = NULL;
258 			mapsize = 0;
259 		} else {
260 			memset(map, 0xff, mapsize);
261 		}
262 		nv_add_uint8(nvout, HAST_SYNCSRC_PRIMARY, "syncsrc");
263 	} else if (
264 	    /* Is primary is out-of-date? */
265 	    (res->hr_secondary_localcnt > res->hr_primary_remotecnt &&
266 	     res->hr_secondary_remotecnt == res->hr_primary_localcnt) ||
267 	    /* Node are more or less in sync? */
268 	    (res->hr_secondary_localcnt == res->hr_primary_remotecnt &&
269 	     res->hr_secondary_remotecnt == res->hr_primary_localcnt) ||
270 	    /* Is secondary is out-of-date? */
271 	    (res->hr_secondary_localcnt == res->hr_primary_remotecnt &&
272 	     res->hr_secondary_remotecnt < res->hr_primary_localcnt)) {
273 		/*
274 		 * Nodes are more or less in sync or one of the nodes is
275 		 * out-of-date.
276 		 * It doesn't matter at this point which one, we just have to
277 		 * send out local bitmap to the remote node.
278 		 */
279 		if (pread(res->hr_localfd, map, mapsize, METADATA_SIZE) !=
280 		    (ssize_t)mapsize) {
281 			pjdlog_exit(LOG_ERR, "Unable to read activemap");
282 		}
283 		if (res->hr_secondary_localcnt > res->hr_primary_remotecnt &&
284 		     res->hr_secondary_remotecnt == res->hr_primary_localcnt) {
285 			/* Primary is out-of-date, sync from secondary. */
286 			nv_add_uint8(nvout, HAST_SYNCSRC_SECONDARY, "syncsrc");
287 		} else {
288 			/*
289 			 * Secondary is out-of-date or counts match.
290 			 * Sync from primary.
291 			 */
292 			nv_add_uint8(nvout, HAST_SYNCSRC_PRIMARY, "syncsrc");
293 		}
294 	} else if (res->hr_secondary_localcnt > res->hr_primary_remotecnt &&
295 	     res->hr_primary_localcnt > res->hr_secondary_remotecnt) {
296 		/*
297 		 * Not good, we have split-brain condition.
298 		 */
299 		pjdlog_error("Split-brain detected, exiting.");
300 		nv_add_string(nvout, "Split-brain condition!", "errmsg");
301 		free(map);
302 		map = NULL;
303 		mapsize = 0;
304 	} else /* if (res->hr_secondary_localcnt < res->hr_primary_remotecnt ||
305 	    res->hr_primary_localcnt < res->hr_secondary_remotecnt) */ {
306 		/*
307 		 * This should never happen in practise, but we will perform
308 		 * full synchronization.
309 		 */
310 		assert(res->hr_secondary_localcnt < res->hr_primary_remotecnt ||
311 		    res->hr_primary_localcnt < res->hr_secondary_remotecnt);
312 		mapsize = activemap_calc_ondisk_size(res->hr_local_mediasize -
313 		    METADATA_SIZE, res->hr_extentsize,
314 		    res->hr_local_sectorsize);
315 		memset(map, 0xff, mapsize);
316 		if (res->hr_secondary_localcnt > res->hr_primary_remotecnt) {
317 			/* In this one of five cases sync from secondary. */
318 			nv_add_uint8(nvout, HAST_SYNCSRC_SECONDARY, "syncsrc");
319 		} else {
320 			/* For the rest four cases sync from primary. */
321 			nv_add_uint8(nvout, HAST_SYNCSRC_PRIMARY, "syncsrc");
322 		}
323 		pjdlog_warning("This should never happen, asking for full synchronization (primary(local=%ju, remote=%ju), secondary(local=%ju, remote=%ju)).",
324 		    (uintmax_t)res->hr_primary_localcnt,
325 		    (uintmax_t)res->hr_primary_remotecnt,
326 		    (uintmax_t)res->hr_secondary_localcnt,
327 		    (uintmax_t)res->hr_secondary_remotecnt);
328 	}
329 	if (hast_proto_send(res, res->hr_remotein, nvout, map, mapsize) < 0) {
330 		pjdlog_exit(EX_TEMPFAIL, "Unable to send activemap to %s",
331 		    res->hr_remoteaddr);
332 	}
333 	if (map != NULL)
334 		free(map);
335 	nv_free(nvout);
336 	if (res->hr_secondary_localcnt > res->hr_primary_remotecnt &&
337 	     res->hr_primary_localcnt > res->hr_secondary_remotecnt) {
338 		/* Exit on split-brain. */
339 		event_send(res, EVENT_SPLITBRAIN);
340 		exit(EX_CONFIG);
341 	}
342 }
343 
344 void
345 hastd_secondary(struct hast_resource *res, struct nv *nvin)
346 {
347 	sigset_t mask;
348 	pthread_t td;
349 	pid_t pid;
350 	int error;
351 
352 	/*
353 	 * Create communication channel between parent and child.
354 	 */
355 	if (proto_client("socketpair://", &res->hr_ctrl) < 0) {
356 		KEEP_ERRNO((void)pidfile_remove(pfh));
357 		pjdlog_exit(EX_OSERR,
358 		    "Unable to create control sockets between parent and child");
359 	}
360 	/*
361 	 * Create communication channel between child and parent.
362 	 */
363 	if (proto_client("socketpair://", &res->hr_event) < 0) {
364 		KEEP_ERRNO((void)pidfile_remove(pfh));
365 		pjdlog_exit(EX_OSERR,
366 		    "Unable to create event sockets between child and parent");
367 	}
368 
369 	pid = fork();
370 	if (pid < 0) {
371 		KEEP_ERRNO((void)pidfile_remove(pfh));
372 		pjdlog_exit(EX_OSERR, "Unable to fork");
373 	}
374 
375 	if (pid > 0) {
376 		/* This is parent. */
377 		proto_close(res->hr_remotein);
378 		res->hr_remotein = NULL;
379 		proto_close(res->hr_remoteout);
380 		res->hr_remoteout = NULL;
381 		/* Declare that we are receiver. */
382 		proto_recv(res->hr_event, NULL, 0);
383 		res->hr_workerpid = pid;
384 		return;
385 	}
386 
387 	gres = res;
388 
389 	(void)pidfile_close(pfh);
390 	hook_fini();
391 
392 	setproctitle("%s (secondary)", res->hr_name);
393 
394 	PJDLOG_VERIFY(sigemptyset(&mask) == 0);
395 	PJDLOG_VERIFY(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
396 
397 	/* Declare that we are sender. */
398 	proto_send(res->hr_event, NULL, 0);
399 
400 	/* Error in setting timeout is not critical, but why should it fail? */
401 	if (proto_timeout(res->hr_remotein, 0) < 0)
402 		pjdlog_errno(LOG_WARNING, "Unable to set connection timeout");
403 	if (proto_timeout(res->hr_remoteout, res->hr_timeout) < 0)
404 		pjdlog_errno(LOG_WARNING, "Unable to set connection timeout");
405 
406 	init_local(res);
407 	init_environment();
408 
409 	/*
410 	 * Create the control thread before sending any event to the parent,
411 	 * as we can deadlock when parent sends control request to worker,
412 	 * but worker has no control thread started yet, so parent waits.
413 	 * In the meantime worker sends an event to the parent, but parent
414 	 * is unable to handle the event, because it waits for control
415 	 * request response.
416 	 */
417 	error = pthread_create(&td, NULL, ctrl_thread, res);
418 	assert(error == 0);
419 
420 	init_remote(res, nvin);
421 	event_send(res, EVENT_CONNECT);
422 
423 	error = pthread_create(&td, NULL, recv_thread, res);
424 	assert(error == 0);
425 	error = pthread_create(&td, NULL, disk_thread, res);
426 	assert(error == 0);
427 	(void)send_thread(res);
428 }
429 
430 static void
431 reqlog(int loglevel, int debuglevel, int error, struct hio *hio, const char *fmt, ...)
432 {
433 	char msg[1024];
434 	va_list ap;
435 	int len;
436 
437 	va_start(ap, fmt);
438 	len = vsnprintf(msg, sizeof(msg), fmt, ap);
439 	va_end(ap);
440 	if ((size_t)len < sizeof(msg)) {
441 		switch (hio->hio_cmd) {
442 		case HIO_READ:
443 			(void)snprintf(msg + len, sizeof(msg) - len,
444 			    "READ(%ju, %ju).", (uintmax_t)hio->hio_offset,
445 			    (uintmax_t)hio->hio_length);
446 			break;
447 		case HIO_DELETE:
448 			(void)snprintf(msg + len, sizeof(msg) - len,
449 			    "DELETE(%ju, %ju).", (uintmax_t)hio->hio_offset,
450 			    (uintmax_t)hio->hio_length);
451 			break;
452 		case HIO_FLUSH:
453 			(void)snprintf(msg + len, sizeof(msg) - len, "FLUSH.");
454 			break;
455 		case HIO_WRITE:
456 			(void)snprintf(msg + len, sizeof(msg) - len,
457 			    "WRITE(%ju, %ju).", (uintmax_t)hio->hio_offset,
458 			    (uintmax_t)hio->hio_length);
459 			break;
460 		case HIO_KEEPALIVE:
461 			(void)snprintf(msg + len, sizeof(msg) - len, "KEEPALIVE.");
462 			break;
463 		default:
464 			(void)snprintf(msg + len, sizeof(msg) - len,
465 			    "UNKNOWN(%u).", (unsigned int)hio->hio_cmd);
466 			break;
467 		}
468 	}
469 	pjdlog_common(loglevel, debuglevel, error, "%s", msg);
470 }
471 
472 static int
473 requnpack(struct hast_resource *res, struct hio *hio)
474 {
475 
476 	hio->hio_cmd = nv_get_uint8(hio->hio_nv, "cmd");
477 	if (hio->hio_cmd == 0) {
478 		pjdlog_error("Header contains no 'cmd' field.");
479 		hio->hio_error = EINVAL;
480 		goto end;
481 	}
482 	switch (hio->hio_cmd) {
483 	case HIO_KEEPALIVE:
484 		break;
485 	case HIO_READ:
486 	case HIO_WRITE:
487 	case HIO_DELETE:
488 		hio->hio_offset = nv_get_uint64(hio->hio_nv, "offset");
489 		if (nv_error(hio->hio_nv) != 0) {
490 			pjdlog_error("Header is missing 'offset' field.");
491 			hio->hio_error = EINVAL;
492 			goto end;
493 		}
494 		hio->hio_length = nv_get_uint64(hio->hio_nv, "length");
495 		if (nv_error(hio->hio_nv) != 0) {
496 			pjdlog_error("Header is missing 'length' field.");
497 			hio->hio_error = EINVAL;
498 			goto end;
499 		}
500 		if (hio->hio_length == 0) {
501 			pjdlog_error("Data length is zero.");
502 			hio->hio_error = EINVAL;
503 			goto end;
504 		}
505 		if (hio->hio_length > MAXPHYS) {
506 			pjdlog_error("Data length is too large (%ju > %ju).",
507 			    (uintmax_t)hio->hio_length, (uintmax_t)MAXPHYS);
508 			hio->hio_error = EINVAL;
509 			goto end;
510 		}
511 		if ((hio->hio_offset % res->hr_local_sectorsize) != 0) {
512 			pjdlog_error("Offset %ju is not multiple of sector size.",
513 			    (uintmax_t)hio->hio_offset);
514 			hio->hio_error = EINVAL;
515 			goto end;
516 		}
517 		if ((hio->hio_length % res->hr_local_sectorsize) != 0) {
518 			pjdlog_error("Length %ju is not multiple of sector size.",
519 			    (uintmax_t)hio->hio_length);
520 			hio->hio_error = EINVAL;
521 			goto end;
522 		}
523 		if (hio->hio_offset + hio->hio_length >
524 		    (uint64_t)res->hr_datasize) {
525 			pjdlog_error("Data offset is too large (%ju > %ju).",
526 			    (uintmax_t)(hio->hio_offset + hio->hio_length),
527 			    (uintmax_t)res->hr_datasize);
528 			hio->hio_error = EINVAL;
529 			goto end;
530 		}
531 		break;
532 	default:
533 		pjdlog_error("Header contains invalid 'cmd' (%hhu).",
534 		    hio->hio_cmd);
535 		hio->hio_error = EINVAL;
536 		goto end;
537 	}
538 	hio->hio_error = 0;
539 end:
540 	return (hio->hio_error);
541 }
542 
543 static __dead2 void
544 secondary_exit(int exitcode, const char *fmt, ...)
545 {
546 	va_list ap;
547 
548 	assert(exitcode != EX_OK);
549 	va_start(ap, fmt);
550 	pjdlogv_errno(LOG_ERR, fmt, ap);
551 	va_end(ap);
552 	event_send(gres, EVENT_DISCONNECT);
553 	exit(exitcode);
554 }
555 
556 /*
557  * Thread receives requests from the primary node.
558  */
559 static void *
560 recv_thread(void *arg)
561 {
562 	struct hast_resource *res = arg;
563 	struct hio *hio;
564 
565 	for (;;) {
566 		pjdlog_debug(2, "recv: Taking free request.");
567 		QUEUE_TAKE(free, hio);
568 		pjdlog_debug(2, "recv: (%p) Got request.", hio);
569 		if (hast_proto_recv_hdr(res->hr_remotein, &hio->hio_nv) < 0) {
570 			secondary_exit(EX_TEMPFAIL,
571 			    "Unable to receive request header");
572 		}
573 		if (requnpack(res, hio) != 0) {
574 			pjdlog_debug(2,
575 			    "recv: (%p) Moving request to the send queue.",
576 			    hio);
577 			QUEUE_INSERT(send, hio);
578 			continue;
579 		}
580 		reqlog(LOG_DEBUG, 2, -1, hio,
581 		    "recv: (%p) Got request header: ", hio);
582 		if (hio->hio_cmd == HIO_KEEPALIVE) {
583 			pjdlog_debug(2,
584 			    "recv: (%p) Moving request to the free queue.",
585 			    hio);
586 			nv_free(hio->hio_nv);
587 			QUEUE_INSERT(free, hio);
588 			continue;
589 		} else if (hio->hio_cmd == HIO_WRITE) {
590 			if (hast_proto_recv_data(res, res->hr_remotein,
591 			    hio->hio_nv, hio->hio_data, MAXPHYS) < 0) {
592 				secondary_exit(EX_TEMPFAIL,
593 				    "Unable to receive request data");
594 			}
595 		}
596 		pjdlog_debug(2, "recv: (%p) Moving request to the disk queue.",
597 		    hio);
598 		QUEUE_INSERT(disk, hio);
599 	}
600 	/* NOTREACHED */
601 	return (NULL);
602 }
603 
604 /*
605  * Thread reads from or writes to local component and also handles DELETE and
606  * FLUSH requests.
607  */
608 static void *
609 disk_thread(void *arg)
610 {
611 	struct hast_resource *res = arg;
612 	struct hio *hio;
613 	ssize_t ret;
614 	bool clear_activemap;
615 
616 	clear_activemap = true;
617 
618 	for (;;) {
619 		pjdlog_debug(2, "disk: Taking request.");
620 		QUEUE_TAKE(disk, hio);
621 		while (clear_activemap) {
622 			unsigned char *map;
623 			size_t mapsize;
624 
625 			/*
626 			 * When first request is received, it means that primary
627 			 * already received our activemap, merged it and stored
628 			 * locally. We can now safely clear our activemap.
629 			 */
630 			mapsize =
631 			    activemap_calc_ondisk_size(res->hr_local_mediasize -
632 			    METADATA_SIZE, res->hr_extentsize,
633 			    res->hr_local_sectorsize);
634 			map = calloc(1, mapsize);
635 			if (map == NULL) {
636 				pjdlog_warning("Unable to allocate memory to clear local activemap.");
637 				break;
638 			}
639 			if (pwrite(res->hr_localfd, map, mapsize,
640 			    METADATA_SIZE) != (ssize_t)mapsize) {
641 				pjdlog_errno(LOG_WARNING,
642 				    "Unable to store cleared activemap");
643 				free(map);
644 				break;
645 			}
646 			free(map);
647 			clear_activemap = false;
648 			pjdlog_debug(1, "Local activemap cleared.");
649 		}
650 		reqlog(LOG_DEBUG, 2, -1, hio, "disk: (%p) Got request: ", hio);
651 		/* Handle the actual request. */
652 		switch (hio->hio_cmd) {
653 		case HIO_READ:
654 			ret = pread(res->hr_localfd, hio->hio_data,
655 			    hio->hio_length,
656 			    hio->hio_offset + res->hr_localoff);
657 			if (ret < 0)
658 				hio->hio_error = errno;
659 			else if (ret != (int64_t)hio->hio_length)
660 				hio->hio_error = EIO;
661 			else
662 				hio->hio_error = 0;
663 			break;
664 		case HIO_WRITE:
665 			ret = pwrite(res->hr_localfd, hio->hio_data,
666 			    hio->hio_length,
667 			    hio->hio_offset + res->hr_localoff);
668 			if (ret < 0)
669 				hio->hio_error = errno;
670 			else if (ret != (int64_t)hio->hio_length)
671 				hio->hio_error = EIO;
672 			else
673 				hio->hio_error = 0;
674 			break;
675 		case HIO_DELETE:
676 			ret = g_delete(res->hr_localfd,
677 			    hio->hio_offset + res->hr_localoff,
678 			    hio->hio_length);
679 			if (ret < 0)
680 				hio->hio_error = errno;
681 			else
682 				hio->hio_error = 0;
683 			break;
684 		case HIO_FLUSH:
685 			ret = g_flush(res->hr_localfd);
686 			if (ret < 0)
687 				hio->hio_error = errno;
688 			else
689 				hio->hio_error = 0;
690 			break;
691 		}
692 		if (hio->hio_error != 0) {
693 			reqlog(LOG_ERR, 0, hio->hio_error, hio,
694 			    "Request failed: ");
695 		}
696 		pjdlog_debug(2, "disk: (%p) Moving request to the send queue.",
697 		    hio);
698 		QUEUE_INSERT(send, hio);
699 	}
700 	/* NOTREACHED */
701 	return (NULL);
702 }
703 
704 /*
705  * Thread sends requests back to primary node.
706  */
707 static void *
708 send_thread(void *arg)
709 {
710 	struct hast_resource *res = arg;
711 	struct nv *nvout;
712 	struct hio *hio;
713 	void *data;
714 	size_t length;
715 
716 	for (;;) {
717 		pjdlog_debug(2, "send: Taking request.");
718 		QUEUE_TAKE(send, hio);
719 		reqlog(LOG_DEBUG, 2, -1, hio, "send: (%p) Got request: ", hio);
720 		nvout = nv_alloc();
721 		/* Copy sequence number. */
722 		nv_add_uint64(nvout, nv_get_uint64(hio->hio_nv, "seq"), "seq");
723 		switch (hio->hio_cmd) {
724 		case HIO_READ:
725 			if (hio->hio_error == 0) {
726 				data = hio->hio_data;
727 				length = hio->hio_length;
728 				break;
729 			}
730 			/*
731 			 * We send no data in case of an error.
732 			 */
733 			/* FALLTHROUGH */
734 		case HIO_DELETE:
735 		case HIO_FLUSH:
736 		case HIO_WRITE:
737 			data = NULL;
738 			length = 0;
739 			break;
740 		default:
741 			abort();
742 			break;
743 		}
744 		if (hio->hio_error != 0)
745 			nv_add_int16(nvout, hio->hio_error, "error");
746 		if (hast_proto_send(res, res->hr_remoteout, nvout, data,
747 		    length) < 0) {
748 			secondary_exit(EX_TEMPFAIL, "Unable to send reply.");
749 		}
750 		nv_free(nvout);
751 		pjdlog_debug(2, "send: (%p) Moving request to the free queue.",
752 		    hio);
753 		nv_free(hio->hio_nv);
754 		hio->hio_error = 0;
755 		QUEUE_INSERT(free, hio);
756 	}
757 	/* NOTREACHED */
758 	return (NULL);
759 }
760