xref: /freebsd/sbin/hastd/primary.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2009 The FreeBSD Foundation
5  * Copyright (c) 2010-2011 Pawel Jakub Dawidek <pawel@dawidek.net>
6  * All rights reserved.
7  *
8  * This software was developed by Pawel Jakub Dawidek under sponsorship from
9  * the FreeBSD Foundation.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #include <sys/cdefs.h>
34 #include <sys/types.h>
35 #include <sys/time.h>
36 #include <sys/bio.h>
37 #include <sys/disk.h>
38 #include <sys/stat.h>
39 
40 #include <geom/gate/g_gate.h>
41 
42 #include <err.h>
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <libgeom.h>
46 #include <pthread.h>
47 #include <signal.h>
48 #include <stdint.h>
49 #include <stdio.h>
50 #include <string.h>
51 #include <sysexits.h>
52 #include <unistd.h>
53 
54 #include <activemap.h>
55 #include <nv.h>
56 #include <rangelock.h>
57 
58 #include "control.h"
59 #include "event.h"
60 #include "hast.h"
61 #include "hast_proto.h"
62 #include "hastd.h"
63 #include "hooks.h"
64 #include "metadata.h"
65 #include "proto.h"
66 #include "pjdlog.h"
67 #include "refcnt.h"
68 #include "subr.h"
69 #include "synch.h"
70 
71 /* The is only one remote component for now. */
72 #define	ISREMOTE(no)	((no) == 1)
73 
74 struct hio {
75 	/*
76 	 * Number of components we are still waiting for.
77 	 * When this field goes to 0, we can send the request back to the
78 	 * kernel. Each component has to decrease this counter by one
79 	 * even on failure.
80 	 */
81 	refcnt_t		 hio_countdown;
82 	/*
83 	 * Each component has a place to store its own error.
84 	 * Once the request is handled by all components we can decide if the
85 	 * request overall is successful or not.
86 	 */
87 	int			*hio_errors;
88 	/*
89 	 * Structure used to communicate with GEOM Gate class.
90 	 */
91 	struct g_gate_ctl_io	 hio_ggio;
92 	/*
93 	 * Request was already confirmed to GEOM Gate.
94 	 */
95 	bool			 hio_done;
96 	/*
97 	 * Number of components we are still waiting before sending write
98 	 * completion ack to GEOM Gate. Used for memsync.
99 	 */
100 	refcnt_t		 hio_writecount;
101 	/*
102 	 * Memsync request was acknowledged by remote.
103 	 */
104 	bool			 hio_memsyncacked;
105 	/*
106 	 * Remember replication from the time the request was initiated,
107 	 * so we won't get confused when replication changes on reload.
108 	 */
109 	int			 hio_replication;
110 	TAILQ_ENTRY(hio)	*hio_next;
111 };
112 #define	hio_free_next	hio_next[0]
113 #define	hio_done_next	hio_next[0]
114 
115 /*
116  * Free list holds unused structures. When free list is empty, we have to wait
117  * until some in-progress requests are freed.
118  */
119 static TAILQ_HEAD(, hio) hio_free_list;
120 static size_t hio_free_list_size;
121 static pthread_mutex_t hio_free_list_lock;
122 static pthread_cond_t hio_free_list_cond;
123 /*
124  * There is one send list for every component. One requests is placed on all
125  * send lists - each component gets the same request, but each component is
126  * responsible for managing his own send list.
127  */
128 static TAILQ_HEAD(, hio) *hio_send_list;
129 static size_t *hio_send_list_size;
130 static pthread_mutex_t *hio_send_list_lock;
131 static pthread_cond_t *hio_send_list_cond;
132 #define	hio_send_local_list_size	hio_send_list_size[0]
133 #define	hio_send_remote_list_size	hio_send_list_size[1]
134 /*
135  * There is one recv list for every component, although local components don't
136  * use recv lists as local requests are done synchronously.
137  */
138 static TAILQ_HEAD(, hio) *hio_recv_list;
139 static size_t *hio_recv_list_size;
140 static pthread_mutex_t *hio_recv_list_lock;
141 static pthread_cond_t *hio_recv_list_cond;
142 #define	hio_recv_remote_list_size	hio_recv_list_size[1]
143 /*
144  * Request is placed on done list by the slowest component (the one that
145  * decreased hio_countdown from 1 to 0).
146  */
147 static TAILQ_HEAD(, hio) hio_done_list;
148 static size_t hio_done_list_size;
149 static pthread_mutex_t hio_done_list_lock;
150 static pthread_cond_t hio_done_list_cond;
151 /*
152  * Structure below are for interaction with sync thread.
153  */
154 static bool sync_inprogress;
155 static pthread_mutex_t sync_lock;
156 static pthread_cond_t sync_cond;
157 /*
158  * The lock below allows to synchornize access to remote connections.
159  */
160 static pthread_rwlock_t *hio_remote_lock;
161 
162 /*
163  * Lock to synchronize metadata updates. Also synchronize access to
164  * hr_primary_localcnt and hr_primary_remotecnt fields.
165  */
166 static pthread_mutex_t metadata_lock;
167 
168 /*
169  * Maximum number of outstanding I/O requests.
170  */
171 #define	HAST_HIO_MAX	256
172 /*
173  * Number of components. At this point there are only two components: local
174  * and remote, but in the future it might be possible to use multiple local
175  * and remote components.
176  */
177 #define	HAST_NCOMPONENTS	2
178 
179 #define	ISCONNECTED(res, no)	\
180 	((res)->hr_remotein != NULL && (res)->hr_remoteout != NULL)
181 
182 #define	QUEUE_INSERT1(hio, name, ncomp)	do {				\
183 	mtx_lock(&hio_##name##_list_lock[(ncomp)]);			\
184 	if (TAILQ_EMPTY(&hio_##name##_list[(ncomp)]))			\
185 		cv_broadcast(&hio_##name##_list_cond[(ncomp)]);		\
186 	TAILQ_INSERT_TAIL(&hio_##name##_list[(ncomp)], (hio),		\
187 	    hio_next[(ncomp)]);						\
188 	hio_##name##_list_size[(ncomp)]++;				\
189 	mtx_unlock(&hio_##name##_list_lock[(ncomp)]);			\
190 } while (0)
191 #define	QUEUE_INSERT2(hio, name)	do {				\
192 	mtx_lock(&hio_##name##_list_lock);				\
193 	if (TAILQ_EMPTY(&hio_##name##_list))				\
194 		cv_broadcast(&hio_##name##_list_cond);			\
195 	TAILQ_INSERT_TAIL(&hio_##name##_list, (hio), hio_##name##_next);\
196 	hio_##name##_list_size++;					\
197 	mtx_unlock(&hio_##name##_list_lock);				\
198 } while (0)
199 #define	QUEUE_TAKE1(hio, name, ncomp, timeout)	do {			\
200 	bool _last;							\
201 									\
202 	mtx_lock(&hio_##name##_list_lock[(ncomp)]);			\
203 	_last = false;							\
204 	while (((hio) = TAILQ_FIRST(&hio_##name##_list[(ncomp)])) == NULL && !_last) { \
205 		cv_timedwait(&hio_##name##_list_cond[(ncomp)],		\
206 		    &hio_##name##_list_lock[(ncomp)], (timeout));	\
207 		if ((timeout) != 0)					\
208 			_last = true;					\
209 	}								\
210 	if (hio != NULL) {						\
211 		PJDLOG_ASSERT(hio_##name##_list_size[(ncomp)] != 0);	\
212 		hio_##name##_list_size[(ncomp)]--;			\
213 		TAILQ_REMOVE(&hio_##name##_list[(ncomp)], (hio),	\
214 		    hio_next[(ncomp)]);					\
215 	}								\
216 	mtx_unlock(&hio_##name##_list_lock[(ncomp)]);			\
217 } while (0)
218 #define	QUEUE_TAKE2(hio, name)	do {					\
219 	mtx_lock(&hio_##name##_list_lock);				\
220 	while (((hio) = TAILQ_FIRST(&hio_##name##_list)) == NULL) {	\
221 		cv_wait(&hio_##name##_list_cond,			\
222 		    &hio_##name##_list_lock);				\
223 	}								\
224 	PJDLOG_ASSERT(hio_##name##_list_size != 0);			\
225 	hio_##name##_list_size--;					\
226 	TAILQ_REMOVE(&hio_##name##_list, (hio), hio_##name##_next);	\
227 	mtx_unlock(&hio_##name##_list_lock);				\
228 } while (0)
229 
230 #define ISFULLSYNC(hio)	((hio)->hio_replication == HAST_REPLICATION_FULLSYNC)
231 #define ISMEMSYNC(hio)	((hio)->hio_replication == HAST_REPLICATION_MEMSYNC)
232 #define ISASYNC(hio)	((hio)->hio_replication == HAST_REPLICATION_ASYNC)
233 
234 #define	SYNCREQ(hio)		do {					\
235 	(hio)->hio_ggio.gctl_unit = -1;					\
236 	(hio)->hio_ggio.gctl_seq = 1;					\
237 } while (0)
238 #define	ISSYNCREQ(hio)		((hio)->hio_ggio.gctl_unit == -1)
239 #define	SYNCREQDONE(hio)	do { (hio)->hio_ggio.gctl_unit = -2; } while (0)
240 #define	ISSYNCREQDONE(hio)	((hio)->hio_ggio.gctl_unit == -2)
241 
242 #define ISMEMSYNCWRITE(hio)	(ISMEMSYNC(hio) &&			\
243 	    (hio)->hio_ggio.gctl_cmd == BIO_WRITE && !ISSYNCREQ(hio))
244 
245 static struct hast_resource *gres;
246 
247 static pthread_mutex_t range_lock;
248 static struct rangelocks *range_regular;
249 static bool range_regular_wait;
250 static pthread_cond_t range_regular_cond;
251 static struct rangelocks *range_sync;
252 static bool range_sync_wait;
253 static pthread_cond_t range_sync_cond;
254 static bool fullystarted;
255 
256 static void *ggate_recv_thread(void *arg);
257 static void *local_send_thread(void *arg);
258 static void *remote_send_thread(void *arg);
259 static void *remote_recv_thread(void *arg);
260 static void *ggate_send_thread(void *arg);
261 static void *sync_thread(void *arg);
262 static void *guard_thread(void *arg);
263 
264 static void
265 output_status_aux(struct nv *nvout)
266 {
267 
268 	nv_add_uint64(nvout, (uint64_t)hio_free_list_size,
269 	    "idle_queue_size");
270 	nv_add_uint64(nvout, (uint64_t)hio_send_local_list_size,
271 	    "local_queue_size");
272 	nv_add_uint64(nvout, (uint64_t)hio_send_remote_list_size,
273 	    "send_queue_size");
274 	nv_add_uint64(nvout, (uint64_t)hio_recv_remote_list_size,
275 	    "recv_queue_size");
276 	nv_add_uint64(nvout, (uint64_t)hio_done_list_size,
277 	    "done_queue_size");
278 }
279 
280 static void
281 cleanup(struct hast_resource *res)
282 {
283 	int rerrno;
284 
285 	/* Remember errno. */
286 	rerrno = errno;
287 
288 	/* Destroy ggate provider if we created one. */
289 	if (res->hr_ggateunit >= 0) {
290 		struct g_gate_ctl_destroy ggiod;
291 
292 		bzero(&ggiod, sizeof(ggiod));
293 		ggiod.gctl_version = G_GATE_VERSION;
294 		ggiod.gctl_unit = res->hr_ggateunit;
295 		ggiod.gctl_force = 1;
296 		if (ioctl(res->hr_ggatefd, G_GATE_CMD_DESTROY, &ggiod) == -1) {
297 			pjdlog_errno(LOG_WARNING,
298 			    "Unable to destroy hast/%s device",
299 			    res->hr_provname);
300 		}
301 		res->hr_ggateunit = -1;
302 	}
303 
304 	/* Restore errno. */
305 	errno = rerrno;
306 }
307 
308 static __dead2 void
309 primary_exit(int exitcode, const char *fmt, ...)
310 {
311 	va_list ap;
312 
313 	PJDLOG_ASSERT(exitcode != EX_OK);
314 	va_start(ap, fmt);
315 	pjdlogv_errno(LOG_ERR, fmt, ap);
316 	va_end(ap);
317 	cleanup(gres);
318 	exit(exitcode);
319 }
320 
321 static __dead2 void
322 primary_exitx(int exitcode, const char *fmt, ...)
323 {
324 	va_list ap;
325 
326 	va_start(ap, fmt);
327 	pjdlogv(exitcode == EX_OK ? LOG_INFO : LOG_ERR, fmt, ap);
328 	va_end(ap);
329 	cleanup(gres);
330 	exit(exitcode);
331 }
332 
333 static int
334 hast_activemap_flush(struct hast_resource *res) __unlocks(res->hr_amp_lock)
335 {
336 	const unsigned char *buf;
337 	size_t size;
338 	int ret;
339 
340 	mtx_lock(&res->hr_amp_diskmap_lock);
341 	buf = activemap_bitmap(res->hr_amp, &size);
342 	mtx_unlock(&res->hr_amp_lock);
343 	PJDLOG_ASSERT(buf != NULL);
344 	PJDLOG_ASSERT((size % res->hr_local_sectorsize) == 0);
345 	ret = 0;
346 	if (pwrite(res->hr_localfd, buf, size, METADATA_SIZE) !=
347 	    (ssize_t)size) {
348 		pjdlog_errno(LOG_ERR, "Unable to flush activemap to disk");
349 		res->hr_stat_activemap_write_error++;
350 		ret = -1;
351 	}
352 	if (ret == 0 && res->hr_metaflush == 1 &&
353 	    g_flush(res->hr_localfd) == -1) {
354 		if (errno == EOPNOTSUPP) {
355 			pjdlog_warning("The %s provider doesn't support flushing write cache. Disabling it.",
356 			    res->hr_localpath);
357 			res->hr_metaflush = 0;
358 		} else {
359 			pjdlog_errno(LOG_ERR,
360 			    "Unable to flush disk cache on activemap update");
361 			res->hr_stat_activemap_flush_error++;
362 			ret = -1;
363 		}
364 	}
365 	mtx_unlock(&res->hr_amp_diskmap_lock);
366 	return (ret);
367 }
368 
369 static bool
370 real_remote(const struct hast_resource *res)
371 {
372 
373 	return (strcmp(res->hr_remoteaddr, "none") != 0);
374 }
375 
376 static void
377 init_environment(struct hast_resource *res __unused)
378 {
379 	struct hio *hio;
380 	unsigned int ii, ncomps;
381 
382 	/*
383 	 * In the future it might be per-resource value.
384 	 */
385 	ncomps = HAST_NCOMPONENTS;
386 
387 	/*
388 	 * Allocate memory needed by lists.
389 	 */
390 	hio_send_list = malloc(sizeof(hio_send_list[0]) * ncomps);
391 	if (hio_send_list == NULL) {
392 		primary_exitx(EX_TEMPFAIL,
393 		    "Unable to allocate %zu bytes of memory for send lists.",
394 		    sizeof(hio_send_list[0]) * ncomps);
395 	}
396 	hio_send_list_size = malloc(sizeof(hio_send_list_size[0]) * ncomps);
397 	if (hio_send_list_size == NULL) {
398 		primary_exitx(EX_TEMPFAIL,
399 		    "Unable to allocate %zu bytes of memory for send list counters.",
400 		    sizeof(hio_send_list_size[0]) * ncomps);
401 	}
402 	hio_send_list_lock = malloc(sizeof(hio_send_list_lock[0]) * ncomps);
403 	if (hio_send_list_lock == NULL) {
404 		primary_exitx(EX_TEMPFAIL,
405 		    "Unable to allocate %zu bytes of memory for send list locks.",
406 		    sizeof(hio_send_list_lock[0]) * ncomps);
407 	}
408 	hio_send_list_cond = malloc(sizeof(hio_send_list_cond[0]) * ncomps);
409 	if (hio_send_list_cond == NULL) {
410 		primary_exitx(EX_TEMPFAIL,
411 		    "Unable to allocate %zu bytes of memory for send list condition variables.",
412 		    sizeof(hio_send_list_cond[0]) * ncomps);
413 	}
414 	hio_recv_list = malloc(sizeof(hio_recv_list[0]) * ncomps);
415 	if (hio_recv_list == NULL) {
416 		primary_exitx(EX_TEMPFAIL,
417 		    "Unable to allocate %zu bytes of memory for recv lists.",
418 		    sizeof(hio_recv_list[0]) * ncomps);
419 	}
420 	hio_recv_list_size = malloc(sizeof(hio_recv_list_size[0]) * ncomps);
421 	if (hio_recv_list_size == NULL) {
422 		primary_exitx(EX_TEMPFAIL,
423 		    "Unable to allocate %zu bytes of memory for recv list counters.",
424 		    sizeof(hio_recv_list_size[0]) * ncomps);
425 	}
426 	hio_recv_list_lock = malloc(sizeof(hio_recv_list_lock[0]) * ncomps);
427 	if (hio_recv_list_lock == NULL) {
428 		primary_exitx(EX_TEMPFAIL,
429 		    "Unable to allocate %zu bytes of memory for recv list locks.",
430 		    sizeof(hio_recv_list_lock[0]) * ncomps);
431 	}
432 	hio_recv_list_cond = malloc(sizeof(hio_recv_list_cond[0]) * ncomps);
433 	if (hio_recv_list_cond == NULL) {
434 		primary_exitx(EX_TEMPFAIL,
435 		    "Unable to allocate %zu bytes of memory for recv list condition variables.",
436 		    sizeof(hio_recv_list_cond[0]) * ncomps);
437 	}
438 	hio_remote_lock = malloc(sizeof(hio_remote_lock[0]) * ncomps);
439 	if (hio_remote_lock == NULL) {
440 		primary_exitx(EX_TEMPFAIL,
441 		    "Unable to allocate %zu bytes of memory for remote connections locks.",
442 		    sizeof(hio_remote_lock[0]) * ncomps);
443 	}
444 
445 	/*
446 	 * Initialize lists, their counters, locks and condition variables.
447 	 */
448 	TAILQ_INIT(&hio_free_list);
449 	mtx_init(&hio_free_list_lock);
450 	cv_init(&hio_free_list_cond);
451 	for (ii = 0; ii < HAST_NCOMPONENTS; ii++) {
452 		TAILQ_INIT(&hio_send_list[ii]);
453 		hio_send_list_size[ii] = 0;
454 		mtx_init(&hio_send_list_lock[ii]);
455 		cv_init(&hio_send_list_cond[ii]);
456 		TAILQ_INIT(&hio_recv_list[ii]);
457 		hio_recv_list_size[ii] = 0;
458 		mtx_init(&hio_recv_list_lock[ii]);
459 		cv_init(&hio_recv_list_cond[ii]);
460 		rw_init(&hio_remote_lock[ii]);
461 	}
462 	TAILQ_INIT(&hio_done_list);
463 	mtx_init(&hio_done_list_lock);
464 	cv_init(&hio_done_list_cond);
465 	mtx_init(&metadata_lock);
466 
467 	/*
468 	 * Allocate requests pool and initialize requests.
469 	 */
470 	for (ii = 0; ii < HAST_HIO_MAX; ii++) {
471 		hio = malloc(sizeof(*hio));
472 		if (hio == NULL) {
473 			primary_exitx(EX_TEMPFAIL,
474 			    "Unable to allocate %zu bytes of memory for hio request.",
475 			    sizeof(*hio));
476 		}
477 		refcnt_init(&hio->hio_countdown, 0);
478 		hio->hio_errors = malloc(sizeof(hio->hio_errors[0]) * ncomps);
479 		if (hio->hio_errors == NULL) {
480 			primary_exitx(EX_TEMPFAIL,
481 			    "Unable allocate %zu bytes of memory for hio errors.",
482 			    sizeof(hio->hio_errors[0]) * ncomps);
483 		}
484 		hio->hio_next = malloc(sizeof(hio->hio_next[0]) * ncomps);
485 		if (hio->hio_next == NULL) {
486 			primary_exitx(EX_TEMPFAIL,
487 			    "Unable allocate %zu bytes of memory for hio_next field.",
488 			    sizeof(hio->hio_next[0]) * ncomps);
489 		}
490 		hio->hio_ggio.gctl_version = G_GATE_VERSION;
491 		hio->hio_ggio.gctl_data = malloc(MAXPHYS);
492 		if (hio->hio_ggio.gctl_data == NULL) {
493 			primary_exitx(EX_TEMPFAIL,
494 			    "Unable to allocate %zu bytes of memory for gctl_data.",
495 			    MAXPHYS);
496 		}
497 		hio->hio_ggio.gctl_length = MAXPHYS;
498 		hio->hio_ggio.gctl_error = 0;
499 		TAILQ_INSERT_HEAD(&hio_free_list, hio, hio_free_next);
500 		hio_free_list_size++;
501 	}
502 }
503 
504 static bool
505 init_resuid(struct hast_resource *res)
506 {
507 
508 	mtx_lock(&metadata_lock);
509 	if (res->hr_resuid != 0) {
510 		mtx_unlock(&metadata_lock);
511 		return (false);
512 	} else {
513 		/* Initialize unique resource identifier. */
514 		arc4random_buf(&res->hr_resuid, sizeof(res->hr_resuid));
515 		mtx_unlock(&metadata_lock);
516 		if (metadata_write(res) == -1)
517 			exit(EX_NOINPUT);
518 		return (true);
519 	}
520 }
521 
522 static void
523 init_local(struct hast_resource *res)
524 {
525 	unsigned char *buf;
526 	size_t mapsize;
527 
528 	if (metadata_read(res, true) == -1)
529 		exit(EX_NOINPUT);
530 	mtx_init(&res->hr_amp_lock);
531 	if (activemap_init(&res->hr_amp, res->hr_datasize, res->hr_extentsize,
532 	    res->hr_local_sectorsize, res->hr_keepdirty) == -1) {
533 		primary_exit(EX_TEMPFAIL, "Unable to create activemap");
534 	}
535 	mtx_init(&range_lock);
536 	cv_init(&range_regular_cond);
537 	if (rangelock_init(&range_regular) == -1)
538 		primary_exit(EX_TEMPFAIL, "Unable to create regular range lock");
539 	cv_init(&range_sync_cond);
540 	if (rangelock_init(&range_sync) == -1)
541 		primary_exit(EX_TEMPFAIL, "Unable to create sync range lock");
542 	mapsize = activemap_ondisk_size(res->hr_amp);
543 	buf = calloc(1, mapsize);
544 	if (buf == NULL) {
545 		primary_exitx(EX_TEMPFAIL,
546 		    "Unable to allocate buffer for activemap.");
547 	}
548 	if (pread(res->hr_localfd, buf, mapsize, METADATA_SIZE) !=
549 	    (ssize_t)mapsize) {
550 		primary_exit(EX_NOINPUT, "Unable to read activemap");
551 	}
552 	activemap_copyin(res->hr_amp, buf, mapsize);
553 	free(buf);
554 	if (res->hr_resuid != 0)
555 		return;
556 	/*
557 	 * We're using provider for the first time. Initialize local and remote
558 	 * counters. We don't initialize resuid here, as we want to do it just
559 	 * in time. The reason for this is that we want to inform secondary
560 	 * that there were no writes yet, so there is no need to synchronize
561 	 * anything.
562 	 */
563 	res->hr_primary_localcnt = 0;
564 	res->hr_primary_remotecnt = 0;
565 	if (metadata_write(res) == -1)
566 		exit(EX_NOINPUT);
567 }
568 
569 static int
570 primary_connect(struct hast_resource *res, struct proto_conn **connp)
571 {
572 	struct proto_conn *conn;
573 	int16_t val;
574 
575 	val = 1;
576 	if (proto_send(res->hr_conn, &val, sizeof(val)) == -1) {
577 		primary_exit(EX_TEMPFAIL,
578 		    "Unable to send connection request to parent");
579 	}
580 	if (proto_recv(res->hr_conn, &val, sizeof(val)) == -1) {
581 		primary_exit(EX_TEMPFAIL,
582 		    "Unable to receive reply to connection request from parent");
583 	}
584 	if (val != 0) {
585 		errno = val;
586 		pjdlog_errno(LOG_WARNING, "Unable to connect to %s",
587 		    res->hr_remoteaddr);
588 		return (-1);
589 	}
590 	if (proto_connection_recv(res->hr_conn, true, &conn) == -1) {
591 		primary_exit(EX_TEMPFAIL,
592 		    "Unable to receive connection from parent");
593 	}
594 	if (proto_connect_wait(conn, res->hr_timeout) == -1) {
595 		pjdlog_errno(LOG_WARNING, "Unable to connect to %s",
596 		    res->hr_remoteaddr);
597 		proto_close(conn);
598 		return (-1);
599 	}
600 	/* Error in setting timeout is not critical, but why should it fail? */
601 	if (proto_timeout(conn, res->hr_timeout) == -1)
602 		pjdlog_errno(LOG_WARNING, "Unable to set connection timeout");
603 
604 	*connp = conn;
605 
606 	return (0);
607 }
608 
609 /*
610  * Function instructs GEOM_GATE to handle reads directly from within the kernel.
611  */
612 static void
613 enable_direct_reads(struct hast_resource *res)
614 {
615 	struct g_gate_ctl_modify ggiomodify;
616 
617 	bzero(&ggiomodify, sizeof(ggiomodify));
618 	ggiomodify.gctl_version = G_GATE_VERSION;
619 	ggiomodify.gctl_unit = res->hr_ggateunit;
620 	ggiomodify.gctl_modify = GG_MODIFY_READPROV | GG_MODIFY_READOFFSET;
621 	strlcpy(ggiomodify.gctl_readprov, res->hr_localpath,
622 	    sizeof(ggiomodify.gctl_readprov));
623 	ggiomodify.gctl_readoffset = res->hr_localoff;
624 	if (ioctl(res->hr_ggatefd, G_GATE_CMD_MODIFY, &ggiomodify) == 0)
625 		pjdlog_debug(1, "Direct reads enabled.");
626 	else
627 		pjdlog_errno(LOG_WARNING, "Failed to enable direct reads");
628 }
629 
630 static int
631 init_remote(struct hast_resource *res, struct proto_conn **inp,
632     struct proto_conn **outp)
633 {
634 	struct proto_conn *in, *out;
635 	struct nv *nvout, *nvin;
636 	const unsigned char *token;
637 	unsigned char *map;
638 	const char *errmsg;
639 	int32_t extentsize;
640 	int64_t datasize;
641 	uint32_t mapsize;
642 	uint8_t version;
643 	size_t size;
644 	int error;
645 
646 	PJDLOG_ASSERT((inp == NULL && outp == NULL) || (inp != NULL && outp != NULL));
647 	PJDLOG_ASSERT(real_remote(res));
648 
649 	in = out = NULL;
650 	errmsg = NULL;
651 
652 	if (primary_connect(res, &out) == -1)
653 		return (ECONNREFUSED);
654 
655 	error = ECONNABORTED;
656 
657 	/*
658 	 * First handshake step.
659 	 * Setup outgoing connection with remote node.
660 	 */
661 	nvout = nv_alloc();
662 	nv_add_string(nvout, res->hr_name, "resource");
663 	nv_add_uint8(nvout, HAST_PROTO_VERSION, "version");
664 	if (nv_error(nvout) != 0) {
665 		pjdlog_common(LOG_WARNING, 0, nv_error(nvout),
666 		    "Unable to allocate header for connection with %s",
667 		    res->hr_remoteaddr);
668 		nv_free(nvout);
669 		goto close;
670 	}
671 	if (hast_proto_send(res, out, nvout, NULL, 0) == -1) {
672 		pjdlog_errno(LOG_WARNING,
673 		    "Unable to send handshake header to %s",
674 		    res->hr_remoteaddr);
675 		nv_free(nvout);
676 		goto close;
677 	}
678 	nv_free(nvout);
679 	if (hast_proto_recv_hdr(out, &nvin) == -1) {
680 		pjdlog_errno(LOG_WARNING,
681 		    "Unable to receive handshake header from %s",
682 		    res->hr_remoteaddr);
683 		goto close;
684 	}
685 	errmsg = nv_get_string(nvin, "errmsg");
686 	if (errmsg != NULL) {
687 		pjdlog_warning("%s", errmsg);
688 		if (nv_exists(nvin, "wait"))
689 			error = EBUSY;
690 		nv_free(nvin);
691 		goto close;
692 	}
693 	version = nv_get_uint8(nvin, "version");
694 	if (version == 0) {
695 		/*
696 		 * If no version is sent, it means this is protocol version 1.
697 		 */
698 		version = 1;
699 	}
700 	if (version > HAST_PROTO_VERSION) {
701 		pjdlog_warning("Invalid version received (%hhu).", version);
702 		nv_free(nvin);
703 		goto close;
704 	}
705 	res->hr_version = version;
706 	pjdlog_debug(1, "Negotiated protocol version %d.", res->hr_version);
707 	token = nv_get_uint8_array(nvin, &size, "token");
708 	if (token == NULL) {
709 		pjdlog_warning("Handshake header from %s has no 'token' field.",
710 		    res->hr_remoteaddr);
711 		nv_free(nvin);
712 		goto close;
713 	}
714 	if (size != sizeof(res->hr_token)) {
715 		pjdlog_warning("Handshake header from %s contains 'token' of wrong size (got %zu, expected %zu).",
716 		    res->hr_remoteaddr, size, sizeof(res->hr_token));
717 		nv_free(nvin);
718 		goto close;
719 	}
720 	bcopy(token, res->hr_token, sizeof(res->hr_token));
721 	nv_free(nvin);
722 
723 	/*
724 	 * Second handshake step.
725 	 * Setup incoming connection with remote node.
726 	 */
727 	if (primary_connect(res, &in) == -1)
728 		goto close;
729 
730 	nvout = nv_alloc();
731 	nv_add_string(nvout, res->hr_name, "resource");
732 	nv_add_uint8_array(nvout, res->hr_token, sizeof(res->hr_token),
733 	    "token");
734 	if (res->hr_resuid == 0) {
735 		/*
736 		 * The resuid field was not yet initialized.
737 		 * Because we do synchronization inside init_resuid(), it is
738 		 * possible that someone already initialized it, the function
739 		 * will return false then, but if we successfully initialized
740 		 * it, we will get true. True means that there were no writes
741 		 * to this resource yet and we want to inform secondary that
742 		 * synchronization is not needed by sending "virgin" argument.
743 		 */
744 		if (init_resuid(res))
745 			nv_add_int8(nvout, 1, "virgin");
746 	}
747 	nv_add_uint64(nvout, res->hr_resuid, "resuid");
748 	nv_add_uint64(nvout, res->hr_primary_localcnt, "localcnt");
749 	nv_add_uint64(nvout, res->hr_primary_remotecnt, "remotecnt");
750 	if (nv_error(nvout) != 0) {
751 		pjdlog_common(LOG_WARNING, 0, nv_error(nvout),
752 		    "Unable to allocate header for connection with %s",
753 		    res->hr_remoteaddr);
754 		nv_free(nvout);
755 		goto close;
756 	}
757 	if (hast_proto_send(res, in, nvout, NULL, 0) == -1) {
758 		pjdlog_errno(LOG_WARNING,
759 		    "Unable to send handshake header to %s",
760 		    res->hr_remoteaddr);
761 		nv_free(nvout);
762 		goto close;
763 	}
764 	nv_free(nvout);
765 	if (hast_proto_recv_hdr(out, &nvin) == -1) {
766 		pjdlog_errno(LOG_WARNING,
767 		    "Unable to receive handshake header from %s",
768 		    res->hr_remoteaddr);
769 		goto close;
770 	}
771 	errmsg = nv_get_string(nvin, "errmsg");
772 	if (errmsg != NULL) {
773 		pjdlog_warning("%s", errmsg);
774 		nv_free(nvin);
775 		goto close;
776 	}
777 	datasize = nv_get_int64(nvin, "datasize");
778 	if (datasize != res->hr_datasize) {
779 		pjdlog_warning("Data size differs between nodes (local=%jd, remote=%jd).",
780 		    (intmax_t)res->hr_datasize, (intmax_t)datasize);
781 		nv_free(nvin);
782 		goto close;
783 	}
784 	extentsize = nv_get_int32(nvin, "extentsize");
785 	if (extentsize != res->hr_extentsize) {
786 		pjdlog_warning("Extent size differs between nodes (local=%zd, remote=%zd).",
787 		    (ssize_t)res->hr_extentsize, (ssize_t)extentsize);
788 		nv_free(nvin);
789 		goto close;
790 	}
791 	res->hr_secondary_localcnt = nv_get_uint64(nvin, "localcnt");
792 	res->hr_secondary_remotecnt = nv_get_uint64(nvin, "remotecnt");
793 	res->hr_syncsrc = nv_get_uint8(nvin, "syncsrc");
794 	if (res->hr_syncsrc == HAST_SYNCSRC_PRIMARY)
795 		enable_direct_reads(res);
796 	if (nv_exists(nvin, "virgin")) {
797 		/*
798 		 * Secondary was reinitialized, bump localcnt if it is 0 as
799 		 * only we have the data.
800 		 */
801 		PJDLOG_ASSERT(res->hr_syncsrc == HAST_SYNCSRC_PRIMARY);
802 		PJDLOG_ASSERT(res->hr_secondary_localcnt == 0);
803 
804 		if (res->hr_primary_localcnt == 0) {
805 			PJDLOG_ASSERT(res->hr_secondary_remotecnt == 0);
806 
807 			mtx_lock(&metadata_lock);
808 			res->hr_primary_localcnt++;
809 			pjdlog_debug(1, "Increasing localcnt to %ju.",
810 			    (uintmax_t)res->hr_primary_localcnt);
811 			(void)metadata_write(res);
812 			mtx_unlock(&metadata_lock);
813 		}
814 	}
815 	map = NULL;
816 	mapsize = nv_get_uint32(nvin, "mapsize");
817 	if (mapsize > 0) {
818 		map = malloc(mapsize);
819 		if (map == NULL) {
820 			pjdlog_error("Unable to allocate memory for remote activemap (mapsize=%ju).",
821 			    (uintmax_t)mapsize);
822 			nv_free(nvin);
823 			goto close;
824 		}
825 		/*
826 		 * Remote node have some dirty extents on its own, lets
827 		 * download its activemap.
828 		 */
829 		if (hast_proto_recv_data(res, out, nvin, map,
830 		    mapsize) == -1) {
831 			pjdlog_errno(LOG_ERR,
832 			    "Unable to receive remote activemap");
833 			nv_free(nvin);
834 			free(map);
835 			goto close;
836 		}
837 		mtx_lock(&res->hr_amp_lock);
838 		/*
839 		 * Merge local and remote bitmaps.
840 		 */
841 		activemap_merge(res->hr_amp, map, mapsize);
842 		free(map);
843 		/*
844 		 * Now that we merged bitmaps from both nodes, flush it to the
845 		 * disk before we start to synchronize.
846 		 */
847 		(void)hast_activemap_flush(res);
848 	}
849 	nv_free(nvin);
850 #ifdef notyet
851 	/* Setup directions. */
852 	if (proto_send(out, NULL, 0) == -1)
853 		pjdlog_errno(LOG_WARNING, "Unable to set connection direction");
854 	if (proto_recv(in, NULL, 0) == -1)
855 		pjdlog_errno(LOG_WARNING, "Unable to set connection direction");
856 #endif
857 	pjdlog_info("Connected to %s.", res->hr_remoteaddr);
858 	if (res->hr_original_replication == HAST_REPLICATION_MEMSYNC &&
859 	    res->hr_version < 2) {
860 		pjdlog_warning("The 'memsync' replication mode is not supported by the remote node, falling back to 'fullsync' mode.");
861 		res->hr_replication = HAST_REPLICATION_FULLSYNC;
862 	} else if (res->hr_replication != res->hr_original_replication) {
863 		/*
864 		 * This is in case hastd disconnected and was upgraded.
865 		 */
866 		res->hr_replication = res->hr_original_replication;
867 	}
868 	if (inp != NULL && outp != NULL) {
869 		*inp = in;
870 		*outp = out;
871 	} else {
872 		res->hr_remotein = in;
873 		res->hr_remoteout = out;
874 	}
875 	event_send(res, EVENT_CONNECT);
876 	return (0);
877 close:
878 	if (errmsg != NULL && strcmp(errmsg, "Split-brain condition!") == 0)
879 		event_send(res, EVENT_SPLITBRAIN);
880 	proto_close(out);
881 	if (in != NULL)
882 		proto_close(in);
883 	return (error);
884 }
885 
886 static void
887 sync_start(void)
888 {
889 
890 	mtx_lock(&sync_lock);
891 	sync_inprogress = true;
892 	mtx_unlock(&sync_lock);
893 	cv_signal(&sync_cond);
894 }
895 
896 static void
897 sync_stop(void)
898 {
899 
900 	mtx_lock(&sync_lock);
901 	if (sync_inprogress)
902 		sync_inprogress = false;
903 	mtx_unlock(&sync_lock);
904 }
905 
906 static void
907 init_ggate(struct hast_resource *res)
908 {
909 	struct g_gate_ctl_create ggiocreate;
910 	struct g_gate_ctl_cancel ggiocancel;
911 
912 	/*
913 	 * We communicate with ggate via /dev/ggctl. Open it.
914 	 */
915 	res->hr_ggatefd = open("/dev/" G_GATE_CTL_NAME, O_RDWR);
916 	if (res->hr_ggatefd == -1)
917 		primary_exit(EX_OSFILE, "Unable to open /dev/" G_GATE_CTL_NAME);
918 	/*
919 	 * Create provider before trying to connect, as connection failure
920 	 * is not critical, but may take some time.
921 	 */
922 	bzero(&ggiocreate, sizeof(ggiocreate));
923 	ggiocreate.gctl_version = G_GATE_VERSION;
924 	ggiocreate.gctl_mediasize = res->hr_datasize;
925 	ggiocreate.gctl_sectorsize = res->hr_local_sectorsize;
926 	ggiocreate.gctl_flags = 0;
927 	ggiocreate.gctl_maxcount = 0;
928 	ggiocreate.gctl_timeout = 0;
929 	ggiocreate.gctl_unit = G_GATE_NAME_GIVEN;
930 	snprintf(ggiocreate.gctl_name, sizeof(ggiocreate.gctl_name), "hast/%s",
931 	    res->hr_provname);
932 	if (ioctl(res->hr_ggatefd, G_GATE_CMD_CREATE, &ggiocreate) == 0) {
933 		pjdlog_info("Device hast/%s created.", res->hr_provname);
934 		res->hr_ggateunit = ggiocreate.gctl_unit;
935 		return;
936 	}
937 	if (errno != EEXIST) {
938 		primary_exit(EX_OSERR, "Unable to create hast/%s device",
939 		    res->hr_provname);
940 	}
941 	pjdlog_debug(1,
942 	    "Device hast/%s already exists, we will try to take it over.",
943 	    res->hr_provname);
944 	/*
945 	 * If we received EEXIST, we assume that the process who created the
946 	 * provider died and didn't clean up. In that case we will start from
947 	 * where he left of.
948 	 */
949 	bzero(&ggiocancel, sizeof(ggiocancel));
950 	ggiocancel.gctl_version = G_GATE_VERSION;
951 	ggiocancel.gctl_unit = G_GATE_NAME_GIVEN;
952 	snprintf(ggiocancel.gctl_name, sizeof(ggiocancel.gctl_name), "hast/%s",
953 	    res->hr_provname);
954 	if (ioctl(res->hr_ggatefd, G_GATE_CMD_CANCEL, &ggiocancel) == 0) {
955 		pjdlog_info("Device hast/%s recovered.", res->hr_provname);
956 		res->hr_ggateunit = ggiocancel.gctl_unit;
957 		return;
958 	}
959 	primary_exit(EX_OSERR, "Unable to take over hast/%s device",
960 	    res->hr_provname);
961 }
962 
963 void
964 hastd_primary(struct hast_resource *res)
965 {
966 	pthread_t td;
967 	pid_t pid;
968 	int error, mode, debuglevel;
969 
970 	/*
971 	 * Create communication channel for sending control commands from
972 	 * parent to child.
973 	 */
974 	if (proto_client(NULL, "socketpair://", &res->hr_ctrl) == -1) {
975 		/* TODO: There's no need for this to be fatal error. */
976 		KEEP_ERRNO((void)pidfile_remove(pfh));
977 		pjdlog_exit(EX_OSERR,
978 		    "Unable to create control sockets between parent and child");
979 	}
980 	/*
981 	 * Create communication channel for sending events from child to parent.
982 	 */
983 	if (proto_client(NULL, "socketpair://", &res->hr_event) == -1) {
984 		/* TODO: There's no need for this to be fatal error. */
985 		KEEP_ERRNO((void)pidfile_remove(pfh));
986 		pjdlog_exit(EX_OSERR,
987 		    "Unable to create event sockets between child and parent");
988 	}
989 	/*
990 	 * Create communication channel for sending connection requests from
991 	 * child to parent.
992 	 */
993 	if (proto_client(NULL, "socketpair://", &res->hr_conn) == -1) {
994 		/* TODO: There's no need for this to be fatal error. */
995 		KEEP_ERRNO((void)pidfile_remove(pfh));
996 		pjdlog_exit(EX_OSERR,
997 		    "Unable to create connection sockets between child and parent");
998 	}
999 
1000 	pid = fork();
1001 	if (pid == -1) {
1002 		/* TODO: There's no need for this to be fatal error. */
1003 		KEEP_ERRNO((void)pidfile_remove(pfh));
1004 		pjdlog_exit(EX_TEMPFAIL, "Unable to fork");
1005 	}
1006 
1007 	if (pid > 0) {
1008 		/* This is parent. */
1009 		/* Declare that we are receiver. */
1010 		proto_recv(res->hr_event, NULL, 0);
1011 		proto_recv(res->hr_conn, NULL, 0);
1012 		/* Declare that we are sender. */
1013 		proto_send(res->hr_ctrl, NULL, 0);
1014 		res->hr_workerpid = pid;
1015 		return;
1016 	}
1017 
1018 	gres = res;
1019 	res->output_status_aux = output_status_aux;
1020 	mode = pjdlog_mode_get();
1021 	debuglevel = pjdlog_debug_get();
1022 
1023 	/* Declare that we are sender. */
1024 	proto_send(res->hr_event, NULL, 0);
1025 	proto_send(res->hr_conn, NULL, 0);
1026 	/* Declare that we are receiver. */
1027 	proto_recv(res->hr_ctrl, NULL, 0);
1028 	descriptors_cleanup(res);
1029 
1030 	descriptors_assert(res, mode);
1031 
1032 	pjdlog_init(mode);
1033 	pjdlog_debug_set(debuglevel);
1034 	pjdlog_prefix_set("[%s] (%s) ", res->hr_name, role2str(res->hr_role));
1035 	setproctitle("%s (%s)", res->hr_name, role2str(res->hr_role));
1036 
1037 	init_local(res);
1038 	init_ggate(res);
1039 	init_environment(res);
1040 
1041 	if (drop_privs(res) != 0) {
1042 		cleanup(res);
1043 		exit(EX_CONFIG);
1044 	}
1045 	pjdlog_info("Privileges successfully dropped.");
1046 
1047 	/*
1048 	 * Create the guard thread first, so we can handle signals from the
1049 	 * very beginning.
1050 	 */
1051 	error = pthread_create(&td, NULL, guard_thread, res);
1052 	PJDLOG_ASSERT(error == 0);
1053 	/*
1054 	 * Create the control thread before sending any event to the parent,
1055 	 * as we can deadlock when parent sends control request to worker,
1056 	 * but worker has no control thread started yet, so parent waits.
1057 	 * In the meantime worker sends an event to the parent, but parent
1058 	 * is unable to handle the event, because it waits for control
1059 	 * request response.
1060 	 */
1061 	error = pthread_create(&td, NULL, ctrl_thread, res);
1062 	PJDLOG_ASSERT(error == 0);
1063 	if (real_remote(res)) {
1064 		error = init_remote(res, NULL, NULL);
1065 		if (error == 0) {
1066 			sync_start();
1067 		} else if (error == EBUSY) {
1068 			time_t start = time(NULL);
1069 
1070 			pjdlog_warning("Waiting for remote node to become %s for %ds.",
1071 			    role2str(HAST_ROLE_SECONDARY),
1072 			    res->hr_timeout);
1073 			for (;;) {
1074 				sleep(1);
1075 				error = init_remote(res, NULL, NULL);
1076 				if (error != EBUSY)
1077 					break;
1078 				if (time(NULL) > start + res->hr_timeout)
1079 					break;
1080 			}
1081 			if (error == EBUSY) {
1082 				pjdlog_warning("Remote node is still %s, starting anyway.",
1083 				    role2str(HAST_ROLE_PRIMARY));
1084 			}
1085 		}
1086 	}
1087 	error = pthread_create(&td, NULL, ggate_recv_thread, res);
1088 	PJDLOG_ASSERT(error == 0);
1089 	error = pthread_create(&td, NULL, local_send_thread, res);
1090 	PJDLOG_ASSERT(error == 0);
1091 	error = pthread_create(&td, NULL, remote_send_thread, res);
1092 	PJDLOG_ASSERT(error == 0);
1093 	error = pthread_create(&td, NULL, remote_recv_thread, res);
1094 	PJDLOG_ASSERT(error == 0);
1095 	error = pthread_create(&td, NULL, ggate_send_thread, res);
1096 	PJDLOG_ASSERT(error == 0);
1097 	fullystarted = true;
1098 	(void)sync_thread(res);
1099 }
1100 
1101 static void
1102 reqlog(int loglevel, int debuglevel, struct g_gate_ctl_io *ggio,
1103     const char *fmt, ...)
1104 {
1105 	char msg[1024];
1106 	va_list ap;
1107 
1108 	va_start(ap, fmt);
1109 	(void)vsnprintf(msg, sizeof(msg), fmt, ap);
1110 	va_end(ap);
1111 	switch (ggio->gctl_cmd) {
1112 	case BIO_READ:
1113 		(void)snprlcat(msg, sizeof(msg), "READ(%ju, %ju).",
1114 		    (uintmax_t)ggio->gctl_offset, (uintmax_t)ggio->gctl_length);
1115 		break;
1116 	case BIO_DELETE:
1117 		(void)snprlcat(msg, sizeof(msg), "DELETE(%ju, %ju).",
1118 		    (uintmax_t)ggio->gctl_offset, (uintmax_t)ggio->gctl_length);
1119 		break;
1120 	case BIO_FLUSH:
1121 		(void)snprlcat(msg, sizeof(msg), "FLUSH.");
1122 		break;
1123 	case BIO_WRITE:
1124 		(void)snprlcat(msg, sizeof(msg), "WRITE(%ju, %ju).",
1125 		    (uintmax_t)ggio->gctl_offset, (uintmax_t)ggio->gctl_length);
1126 		break;
1127 	default:
1128 		(void)snprlcat(msg, sizeof(msg), "UNKNOWN(%u).",
1129 		    (unsigned int)ggio->gctl_cmd);
1130 		break;
1131 	}
1132 	pjdlog_common(loglevel, debuglevel, -1, "%s", msg);
1133 }
1134 
1135 static void
1136 remote_close(struct hast_resource *res, int ncomp)
1137 {
1138 
1139 	rw_wlock(&hio_remote_lock[ncomp]);
1140 	/*
1141 	 * Check for a race between dropping rlock and acquiring wlock -
1142 	 * another thread can close connection in-between.
1143 	 */
1144 	if (!ISCONNECTED(res, ncomp)) {
1145 		PJDLOG_ASSERT(res->hr_remotein == NULL);
1146 		PJDLOG_ASSERT(res->hr_remoteout == NULL);
1147 		rw_unlock(&hio_remote_lock[ncomp]);
1148 		return;
1149 	}
1150 
1151 	PJDLOG_ASSERT(res->hr_remotein != NULL);
1152 	PJDLOG_ASSERT(res->hr_remoteout != NULL);
1153 
1154 	pjdlog_debug(2, "Closing incoming connection to %s.",
1155 	    res->hr_remoteaddr);
1156 	proto_close(res->hr_remotein);
1157 	res->hr_remotein = NULL;
1158 	pjdlog_debug(2, "Closing outgoing connection to %s.",
1159 	    res->hr_remoteaddr);
1160 	proto_close(res->hr_remoteout);
1161 	res->hr_remoteout = NULL;
1162 
1163 	rw_unlock(&hio_remote_lock[ncomp]);
1164 
1165 	pjdlog_warning("Disconnected from %s.", res->hr_remoteaddr);
1166 
1167 	/*
1168 	 * Stop synchronization if in-progress.
1169 	 */
1170 	sync_stop();
1171 
1172 	event_send(res, EVENT_DISCONNECT);
1173 }
1174 
1175 /*
1176  * Acknowledge write completion to the kernel, but don't update activemap yet.
1177  */
1178 static void
1179 write_complete(struct hast_resource *res, struct hio *hio)
1180 {
1181 	struct g_gate_ctl_io *ggio;
1182 	unsigned int ncomp;
1183 
1184 	PJDLOG_ASSERT(!hio->hio_done);
1185 
1186 	ggio = &hio->hio_ggio;
1187 	PJDLOG_ASSERT(ggio->gctl_cmd == BIO_WRITE);
1188 
1189 	/*
1190 	 * Bump local count if this is first write after
1191 	 * connection failure with remote node.
1192 	 */
1193 	ncomp = 1;
1194 	rw_rlock(&hio_remote_lock[ncomp]);
1195 	if (!ISCONNECTED(res, ncomp)) {
1196 		mtx_lock(&metadata_lock);
1197 		if (res->hr_primary_localcnt == res->hr_secondary_remotecnt) {
1198 			res->hr_primary_localcnt++;
1199 			pjdlog_debug(1, "Increasing localcnt to %ju.",
1200 			    (uintmax_t)res->hr_primary_localcnt);
1201 			(void)metadata_write(res);
1202 		}
1203 		mtx_unlock(&metadata_lock);
1204 	}
1205 	rw_unlock(&hio_remote_lock[ncomp]);
1206 	if (ioctl(res->hr_ggatefd, G_GATE_CMD_DONE, ggio) == -1)
1207 		primary_exit(EX_OSERR, "G_GATE_CMD_DONE failed");
1208 	hio->hio_done = true;
1209 }
1210 
1211 /*
1212  * Thread receives ggate I/O requests from the kernel and passes them to
1213  * appropriate threads:
1214  * WRITE - always goes to both local_send and remote_send threads
1215  * READ (when the block is up-to-date on local component) -
1216  *	only local_send thread
1217  * READ (when the block isn't up-to-date on local component) -
1218  *	only remote_send thread
1219  * DELETE - always goes to both local_send and remote_send threads
1220  * FLUSH - always goes to both local_send and remote_send threads
1221  */
1222 static void *
1223 ggate_recv_thread(void *arg)
1224 {
1225 	struct hast_resource *res = arg;
1226 	struct g_gate_ctl_io *ggio;
1227 	struct hio *hio;
1228 	unsigned int ii, ncomp, ncomps;
1229 	int error;
1230 
1231 	for (;;) {
1232 		pjdlog_debug(2, "ggate_recv: Taking free request.");
1233 		QUEUE_TAKE2(hio, free);
1234 		pjdlog_debug(2, "ggate_recv: (%p) Got free request.", hio);
1235 		ggio = &hio->hio_ggio;
1236 		ggio->gctl_unit = res->hr_ggateunit;
1237 		ggio->gctl_length = MAXPHYS;
1238 		ggio->gctl_error = 0;
1239 		hio->hio_done = false;
1240 		hio->hio_replication = res->hr_replication;
1241 		pjdlog_debug(2,
1242 		    "ggate_recv: (%p) Waiting for request from the kernel.",
1243 		    hio);
1244 		if (ioctl(res->hr_ggatefd, G_GATE_CMD_START, ggio) == -1) {
1245 			if (sigexit_received)
1246 				pthread_exit(NULL);
1247 			primary_exit(EX_OSERR, "G_GATE_CMD_START failed");
1248 		}
1249 		error = ggio->gctl_error;
1250 		switch (error) {
1251 		case 0:
1252 			break;
1253 		case ECANCELED:
1254 			/* Exit gracefully. */
1255 			if (!sigexit_received) {
1256 				pjdlog_debug(2,
1257 				    "ggate_recv: (%p) Received cancel from the kernel.",
1258 				    hio);
1259 				pjdlog_info("Received cancel from the kernel, exiting.");
1260 			}
1261 			pthread_exit(NULL);
1262 		case ENOMEM:
1263 			/*
1264 			 * Buffer too small? Impossible, we allocate MAXPHYS
1265 			 * bytes - request can't be bigger than that.
1266 			 */
1267 			/* FALLTHROUGH */
1268 		case ENXIO:
1269 		default:
1270 			primary_exitx(EX_OSERR, "G_GATE_CMD_START failed: %s.",
1271 			    strerror(error));
1272 		}
1273 
1274 		ncomp = 0;
1275 		ncomps = HAST_NCOMPONENTS;
1276 
1277 		for (ii = 0; ii < ncomps; ii++)
1278 			hio->hio_errors[ii] = EINVAL;
1279 		reqlog(LOG_DEBUG, 2, ggio,
1280 		    "ggate_recv: (%p) Request received from the kernel: ",
1281 		    hio);
1282 
1283 		/*
1284 		 * Inform all components about new write request.
1285 		 * For read request prefer local component unless the given
1286 		 * range is out-of-date, then use remote component.
1287 		 */
1288 		switch (ggio->gctl_cmd) {
1289 		case BIO_READ:
1290 			res->hr_stat_read++;
1291 			ncomps = 1;
1292 			mtx_lock(&metadata_lock);
1293 			if (res->hr_syncsrc == HAST_SYNCSRC_UNDEF ||
1294 			    res->hr_syncsrc == HAST_SYNCSRC_PRIMARY) {
1295 				/*
1296 				 * This range is up-to-date on local component,
1297 				 * so handle request locally.
1298 				 */
1299 				 /* Local component is 0 for now. */
1300 				ncomp = 0;
1301 			} else /* if (res->hr_syncsrc ==
1302 			    HAST_SYNCSRC_SECONDARY) */ {
1303 				PJDLOG_ASSERT(res->hr_syncsrc ==
1304 				    HAST_SYNCSRC_SECONDARY);
1305 				/*
1306 				 * This range is out-of-date on local component,
1307 				 * so send request to the remote node.
1308 				 */
1309 				 /* Remote component is 1 for now. */
1310 				ncomp = 1;
1311 			}
1312 			mtx_unlock(&metadata_lock);
1313 			break;
1314 		case BIO_WRITE:
1315 			res->hr_stat_write++;
1316 			if (res->hr_resuid == 0 &&
1317 			    res->hr_primary_localcnt == 0) {
1318 				/* This is first write. */
1319 				res->hr_primary_localcnt = 1;
1320 			}
1321 			for (;;) {
1322 				mtx_lock(&range_lock);
1323 				if (rangelock_islocked(range_sync,
1324 				    ggio->gctl_offset, ggio->gctl_length)) {
1325 					pjdlog_debug(2,
1326 					    "regular: Range offset=%jd length=%zu locked.",
1327 					    (intmax_t)ggio->gctl_offset,
1328 					    (size_t)ggio->gctl_length);
1329 					range_regular_wait = true;
1330 					cv_wait(&range_regular_cond, &range_lock);
1331 					range_regular_wait = false;
1332 					mtx_unlock(&range_lock);
1333 					continue;
1334 				}
1335 				if (rangelock_add(range_regular,
1336 				    ggio->gctl_offset, ggio->gctl_length) == -1) {
1337 					mtx_unlock(&range_lock);
1338 					pjdlog_debug(2,
1339 					    "regular: Range offset=%jd length=%zu is already locked, waiting.",
1340 					    (intmax_t)ggio->gctl_offset,
1341 					    (size_t)ggio->gctl_length);
1342 					sleep(1);
1343 					continue;
1344 				}
1345 				mtx_unlock(&range_lock);
1346 				break;
1347 			}
1348 			mtx_lock(&res->hr_amp_lock);
1349 			if (activemap_write_start(res->hr_amp,
1350 			    ggio->gctl_offset, ggio->gctl_length)) {
1351 				res->hr_stat_activemap_update++;
1352 				(void)hast_activemap_flush(res);
1353 			} else {
1354 				mtx_unlock(&res->hr_amp_lock);
1355 			}
1356 			if (ISMEMSYNC(hio)) {
1357 				hio->hio_memsyncacked = false;
1358 				refcnt_init(&hio->hio_writecount, ncomps);
1359 			}
1360 			break;
1361 		case BIO_DELETE:
1362 			res->hr_stat_delete++;
1363 			break;
1364 		case BIO_FLUSH:
1365 			res->hr_stat_flush++;
1366 			break;
1367 		}
1368 		pjdlog_debug(2,
1369 		    "ggate_recv: (%p) Moving request to the send queues.", hio);
1370 		refcnt_init(&hio->hio_countdown, ncomps);
1371 		for (ii = ncomp; ii < ncomps; ii++)
1372 			QUEUE_INSERT1(hio, send, ii);
1373 	}
1374 	/* NOTREACHED */
1375 	return (NULL);
1376 }
1377 
1378 /*
1379  * Thread reads from or writes to local component.
1380  * If local read fails, it redirects it to remote_send thread.
1381  */
1382 static void *
1383 local_send_thread(void *arg)
1384 {
1385 	struct hast_resource *res = arg;
1386 	struct g_gate_ctl_io *ggio;
1387 	struct hio *hio;
1388 	unsigned int ncomp, rncomp;
1389 	ssize_t ret;
1390 
1391 	/* Local component is 0 for now. */
1392 	ncomp = 0;
1393 	/* Remote component is 1 for now. */
1394 	rncomp = 1;
1395 
1396 	for (;;) {
1397 		pjdlog_debug(2, "local_send: Taking request.");
1398 		QUEUE_TAKE1(hio, send, ncomp, 0);
1399 		pjdlog_debug(2, "local_send: (%p) Got request.", hio);
1400 		ggio = &hio->hio_ggio;
1401 		switch (ggio->gctl_cmd) {
1402 		case BIO_READ:
1403 			ret = pread(res->hr_localfd, ggio->gctl_data,
1404 			    ggio->gctl_length,
1405 			    ggio->gctl_offset + res->hr_localoff);
1406 			if (ret == ggio->gctl_length)
1407 				hio->hio_errors[ncomp] = 0;
1408 			else if (!ISSYNCREQ(hio)) {
1409 				/*
1410 				 * If READ failed, try to read from remote node.
1411 				 */
1412 				if (ret == -1) {
1413 					reqlog(LOG_WARNING, 0, ggio,
1414 					    "Local request failed (%s), trying remote node. ",
1415 					    strerror(errno));
1416 				} else if (ret != ggio->gctl_length) {
1417 					reqlog(LOG_WARNING, 0, ggio,
1418 					    "Local request failed (%zd != %jd), trying remote node. ",
1419 					    ret, (intmax_t)ggio->gctl_length);
1420 				}
1421 				QUEUE_INSERT1(hio, send, rncomp);
1422 				continue;
1423 			}
1424 			break;
1425 		case BIO_WRITE:
1426 			ret = pwrite(res->hr_localfd, ggio->gctl_data,
1427 			    ggio->gctl_length,
1428 			    ggio->gctl_offset + res->hr_localoff);
1429 			if (ret == -1) {
1430 				hio->hio_errors[ncomp] = errno;
1431 				reqlog(LOG_WARNING, 0, ggio,
1432 				    "Local request failed (%s): ",
1433 				    strerror(errno));
1434 			} else if (ret != ggio->gctl_length) {
1435 				hio->hio_errors[ncomp] = EIO;
1436 				reqlog(LOG_WARNING, 0, ggio,
1437 				    "Local request failed (%zd != %jd): ",
1438 				    ret, (intmax_t)ggio->gctl_length);
1439 			} else {
1440 				hio->hio_errors[ncomp] = 0;
1441 				if (ISASYNC(hio)) {
1442 					ggio->gctl_error = 0;
1443 					write_complete(res, hio);
1444 				}
1445 			}
1446 			break;
1447 		case BIO_DELETE:
1448 			ret = g_delete(res->hr_localfd,
1449 			    ggio->gctl_offset + res->hr_localoff,
1450 			    ggio->gctl_length);
1451 			if (ret == -1) {
1452 				hio->hio_errors[ncomp] = errno;
1453 				reqlog(LOG_WARNING, 0, ggio,
1454 				    "Local request failed (%s): ",
1455 				    strerror(errno));
1456 			} else {
1457 				hio->hio_errors[ncomp] = 0;
1458 			}
1459 			break;
1460 		case BIO_FLUSH:
1461 			if (!res->hr_localflush) {
1462 				ret = -1;
1463 				errno = EOPNOTSUPP;
1464 				break;
1465 			}
1466 			ret = g_flush(res->hr_localfd);
1467 			if (ret == -1) {
1468 				if (errno == EOPNOTSUPP)
1469 					res->hr_localflush = false;
1470 				hio->hio_errors[ncomp] = errno;
1471 				reqlog(LOG_WARNING, 0, ggio,
1472 				    "Local request failed (%s): ",
1473 				    strerror(errno));
1474 			} else {
1475 				hio->hio_errors[ncomp] = 0;
1476 			}
1477 			break;
1478 		}
1479 		if (ISMEMSYNCWRITE(hio)) {
1480 			if (refcnt_release(&hio->hio_writecount) == 0) {
1481 				write_complete(res, hio);
1482 			}
1483 		}
1484 		if (refcnt_release(&hio->hio_countdown) > 0)
1485 			continue;
1486 		if (ISSYNCREQ(hio)) {
1487 			mtx_lock(&sync_lock);
1488 			SYNCREQDONE(hio);
1489 			mtx_unlock(&sync_lock);
1490 			cv_signal(&sync_cond);
1491 		} else {
1492 			pjdlog_debug(2,
1493 			    "local_send: (%p) Moving request to the done queue.",
1494 			    hio);
1495 			QUEUE_INSERT2(hio, done);
1496 		}
1497 	}
1498 	/* NOTREACHED */
1499 	return (NULL);
1500 }
1501 
1502 static void
1503 keepalive_send(struct hast_resource *res, unsigned int ncomp)
1504 {
1505 	struct nv *nv;
1506 
1507 	rw_rlock(&hio_remote_lock[ncomp]);
1508 
1509 	if (!ISCONNECTED(res, ncomp)) {
1510 		rw_unlock(&hio_remote_lock[ncomp]);
1511 		return;
1512 	}
1513 
1514 	PJDLOG_ASSERT(res->hr_remotein != NULL);
1515 	PJDLOG_ASSERT(res->hr_remoteout != NULL);
1516 
1517 	nv = nv_alloc();
1518 	nv_add_uint8(nv, HIO_KEEPALIVE, "cmd");
1519 	if (nv_error(nv) != 0) {
1520 		rw_unlock(&hio_remote_lock[ncomp]);
1521 		nv_free(nv);
1522 		pjdlog_debug(1,
1523 		    "keepalive_send: Unable to prepare header to send.");
1524 		return;
1525 	}
1526 	if (hast_proto_send(res, res->hr_remoteout, nv, NULL, 0) == -1) {
1527 		rw_unlock(&hio_remote_lock[ncomp]);
1528 		pjdlog_common(LOG_DEBUG, 1, errno,
1529 		    "keepalive_send: Unable to send request");
1530 		nv_free(nv);
1531 		remote_close(res, ncomp);
1532 		return;
1533 	}
1534 
1535 	rw_unlock(&hio_remote_lock[ncomp]);
1536 	nv_free(nv);
1537 	pjdlog_debug(2, "keepalive_send: Request sent.");
1538 }
1539 
1540 /*
1541  * Thread sends request to secondary node.
1542  */
1543 static void *
1544 remote_send_thread(void *arg)
1545 {
1546 	struct hast_resource *res = arg;
1547 	struct g_gate_ctl_io *ggio;
1548 	time_t lastcheck, now;
1549 	struct hio *hio;
1550 	struct nv *nv;
1551 	unsigned int ncomp;
1552 	bool wakeup;
1553 	uint64_t offset, length;
1554 	uint8_t cmd;
1555 	void *data;
1556 
1557 	/* Remote component is 1 for now. */
1558 	ncomp = 1;
1559 	lastcheck = time(NULL);
1560 
1561 	for (;;) {
1562 		pjdlog_debug(2, "remote_send: Taking request.");
1563 		QUEUE_TAKE1(hio, send, ncomp, HAST_KEEPALIVE);
1564 		if (hio == NULL) {
1565 			now = time(NULL);
1566 			if (lastcheck + HAST_KEEPALIVE <= now) {
1567 				keepalive_send(res, ncomp);
1568 				lastcheck = now;
1569 			}
1570 			continue;
1571 		}
1572 		pjdlog_debug(2, "remote_send: (%p) Got request.", hio);
1573 		ggio = &hio->hio_ggio;
1574 		switch (ggio->gctl_cmd) {
1575 		case BIO_READ:
1576 			cmd = HIO_READ;
1577 			data = NULL;
1578 			offset = ggio->gctl_offset;
1579 			length = ggio->gctl_length;
1580 			break;
1581 		case BIO_WRITE:
1582 			cmd = HIO_WRITE;
1583 			data = ggio->gctl_data;
1584 			offset = ggio->gctl_offset;
1585 			length = ggio->gctl_length;
1586 			break;
1587 		case BIO_DELETE:
1588 			cmd = HIO_DELETE;
1589 			data = NULL;
1590 			offset = ggio->gctl_offset;
1591 			length = ggio->gctl_length;
1592 			break;
1593 		case BIO_FLUSH:
1594 			cmd = HIO_FLUSH;
1595 			data = NULL;
1596 			offset = 0;
1597 			length = 0;
1598 			break;
1599 		default:
1600 			PJDLOG_ABORT("invalid condition");
1601 		}
1602 		nv = nv_alloc();
1603 		nv_add_uint8(nv, cmd, "cmd");
1604 		nv_add_uint64(nv, (uint64_t)ggio->gctl_seq, "seq");
1605 		nv_add_uint64(nv, offset, "offset");
1606 		nv_add_uint64(nv, length, "length");
1607 		if (ISMEMSYNCWRITE(hio))
1608 			nv_add_uint8(nv, 1, "memsync");
1609 		if (nv_error(nv) != 0) {
1610 			hio->hio_errors[ncomp] = nv_error(nv);
1611 			pjdlog_debug(2,
1612 			    "remote_send: (%p) Unable to prepare header to send.",
1613 			    hio);
1614 			reqlog(LOG_ERR, 0, ggio,
1615 			    "Unable to prepare header to send (%s): ",
1616 			    strerror(nv_error(nv)));
1617 			/* Move failed request immediately to the done queue. */
1618 			goto done_queue;
1619 		}
1620 		/*
1621 		 * Protect connection from disappearing.
1622 		 */
1623 		rw_rlock(&hio_remote_lock[ncomp]);
1624 		if (!ISCONNECTED(res, ncomp)) {
1625 			rw_unlock(&hio_remote_lock[ncomp]);
1626 			hio->hio_errors[ncomp] = ENOTCONN;
1627 			goto done_queue;
1628 		}
1629 		/*
1630 		 * Move the request to recv queue before sending it, because
1631 		 * in different order we can get reply before we move request
1632 		 * to recv queue.
1633 		 */
1634 		pjdlog_debug(2,
1635 		    "remote_send: (%p) Moving request to the recv queue.",
1636 		    hio);
1637 		mtx_lock(&hio_recv_list_lock[ncomp]);
1638 		wakeup = TAILQ_EMPTY(&hio_recv_list[ncomp]);
1639 		TAILQ_INSERT_TAIL(&hio_recv_list[ncomp], hio, hio_next[ncomp]);
1640 		hio_recv_list_size[ncomp]++;
1641 		mtx_unlock(&hio_recv_list_lock[ncomp]);
1642 		if (hast_proto_send(res, res->hr_remoteout, nv, data,
1643 		    data != NULL ? length : 0) == -1) {
1644 			hio->hio_errors[ncomp] = errno;
1645 			rw_unlock(&hio_remote_lock[ncomp]);
1646 			pjdlog_debug(2,
1647 			    "remote_send: (%p) Unable to send request.", hio);
1648 			reqlog(LOG_ERR, 0, ggio,
1649 			    "Unable to send request (%s): ",
1650 			    strerror(hio->hio_errors[ncomp]));
1651 			remote_close(res, ncomp);
1652 		} else {
1653 			rw_unlock(&hio_remote_lock[ncomp]);
1654 		}
1655 		nv_free(nv);
1656 		if (wakeup)
1657 			cv_signal(&hio_recv_list_cond[ncomp]);
1658 		continue;
1659 done_queue:
1660 		nv_free(nv);
1661 		if (ISSYNCREQ(hio)) {
1662 			if (refcnt_release(&hio->hio_countdown) > 0)
1663 				continue;
1664 			mtx_lock(&sync_lock);
1665 			SYNCREQDONE(hio);
1666 			mtx_unlock(&sync_lock);
1667 			cv_signal(&sync_cond);
1668 			continue;
1669 		}
1670 		if (ggio->gctl_cmd == BIO_WRITE) {
1671 			mtx_lock(&res->hr_amp_lock);
1672 			if (activemap_need_sync(res->hr_amp, ggio->gctl_offset,
1673 			    ggio->gctl_length)) {
1674 				(void)hast_activemap_flush(res);
1675 			} else {
1676 				mtx_unlock(&res->hr_amp_lock);
1677 			}
1678 			if (ISMEMSYNCWRITE(hio)) {
1679 				if (refcnt_release(&hio->hio_writecount) == 0) {
1680 					if (hio->hio_errors[0] == 0)
1681 						write_complete(res, hio);
1682 				}
1683 			}
1684 		}
1685 		if (refcnt_release(&hio->hio_countdown) > 0)
1686 			continue;
1687 		pjdlog_debug(2,
1688 		    "remote_send: (%p) Moving request to the done queue.",
1689 		    hio);
1690 		QUEUE_INSERT2(hio, done);
1691 	}
1692 	/* NOTREACHED */
1693 	return (NULL);
1694 }
1695 
1696 /*
1697  * Thread receives answer from secondary node and passes it to ggate_send
1698  * thread.
1699  */
1700 static void *
1701 remote_recv_thread(void *arg)
1702 {
1703 	struct hast_resource *res = arg;
1704 	struct g_gate_ctl_io *ggio;
1705 	struct hio *hio;
1706 	struct nv *nv;
1707 	unsigned int ncomp;
1708 	uint64_t seq;
1709 	bool memsyncack;
1710 	int error;
1711 
1712 	/* Remote component is 1 for now. */
1713 	ncomp = 1;
1714 
1715 	for (;;) {
1716 		/* Wait until there is anything to receive. */
1717 		mtx_lock(&hio_recv_list_lock[ncomp]);
1718 		while (TAILQ_EMPTY(&hio_recv_list[ncomp])) {
1719 			pjdlog_debug(2, "remote_recv: No requests, waiting.");
1720 			cv_wait(&hio_recv_list_cond[ncomp],
1721 			    &hio_recv_list_lock[ncomp]);
1722 		}
1723 		mtx_unlock(&hio_recv_list_lock[ncomp]);
1724 
1725 		memsyncack = false;
1726 
1727 		rw_rlock(&hio_remote_lock[ncomp]);
1728 		if (!ISCONNECTED(res, ncomp)) {
1729 			rw_unlock(&hio_remote_lock[ncomp]);
1730 			/*
1731 			 * Connection is dead, so move all pending requests to
1732 			 * the done queue (one-by-one).
1733 			 */
1734 			mtx_lock(&hio_recv_list_lock[ncomp]);
1735 			hio = TAILQ_FIRST(&hio_recv_list[ncomp]);
1736 			PJDLOG_ASSERT(hio != NULL);
1737 			TAILQ_REMOVE(&hio_recv_list[ncomp], hio,
1738 			    hio_next[ncomp]);
1739 			hio_recv_list_size[ncomp]--;
1740 			mtx_unlock(&hio_recv_list_lock[ncomp]);
1741 			hio->hio_errors[ncomp] = ENOTCONN;
1742 			goto done_queue;
1743 		}
1744 		if (hast_proto_recv_hdr(res->hr_remotein, &nv) == -1) {
1745 			pjdlog_errno(LOG_ERR,
1746 			    "Unable to receive reply header");
1747 			rw_unlock(&hio_remote_lock[ncomp]);
1748 			remote_close(res, ncomp);
1749 			continue;
1750 		}
1751 		rw_unlock(&hio_remote_lock[ncomp]);
1752 		seq = nv_get_uint64(nv, "seq");
1753 		if (seq == 0) {
1754 			pjdlog_error("Header contains no 'seq' field.");
1755 			nv_free(nv);
1756 			continue;
1757 		}
1758 		memsyncack = nv_exists(nv, "received");
1759 		mtx_lock(&hio_recv_list_lock[ncomp]);
1760 		TAILQ_FOREACH(hio, &hio_recv_list[ncomp], hio_next[ncomp]) {
1761 			if (hio->hio_ggio.gctl_seq == seq) {
1762 				TAILQ_REMOVE(&hio_recv_list[ncomp], hio,
1763 				    hio_next[ncomp]);
1764 				hio_recv_list_size[ncomp]--;
1765 				break;
1766 			}
1767 		}
1768 		mtx_unlock(&hio_recv_list_lock[ncomp]);
1769 		if (hio == NULL) {
1770 			pjdlog_error("Found no request matching received 'seq' field (%ju).",
1771 			    (uintmax_t)seq);
1772 			nv_free(nv);
1773 			continue;
1774 		}
1775 		ggio = &hio->hio_ggio;
1776 		error = nv_get_int16(nv, "error");
1777 		if (error != 0) {
1778 			/* Request failed on remote side. */
1779 			hio->hio_errors[ncomp] = error;
1780 			reqlog(LOG_WARNING, 0, ggio,
1781 			    "Remote request failed (%s): ", strerror(error));
1782 			nv_free(nv);
1783 			goto done_queue;
1784 		}
1785 		switch (ggio->gctl_cmd) {
1786 		case BIO_READ:
1787 			rw_rlock(&hio_remote_lock[ncomp]);
1788 			if (!ISCONNECTED(res, ncomp)) {
1789 				rw_unlock(&hio_remote_lock[ncomp]);
1790 				nv_free(nv);
1791 				goto done_queue;
1792 			}
1793 			if (hast_proto_recv_data(res, res->hr_remotein, nv,
1794 			    ggio->gctl_data, ggio->gctl_length) == -1) {
1795 				hio->hio_errors[ncomp] = errno;
1796 				pjdlog_errno(LOG_ERR,
1797 				    "Unable to receive reply data");
1798 				rw_unlock(&hio_remote_lock[ncomp]);
1799 				nv_free(nv);
1800 				remote_close(res, ncomp);
1801 				goto done_queue;
1802 			}
1803 			rw_unlock(&hio_remote_lock[ncomp]);
1804 			break;
1805 		case BIO_WRITE:
1806 		case BIO_DELETE:
1807 		case BIO_FLUSH:
1808 			break;
1809 		default:
1810 			PJDLOG_ABORT("invalid condition");
1811 		}
1812 		hio->hio_errors[ncomp] = 0;
1813 		nv_free(nv);
1814 done_queue:
1815 		if (ISMEMSYNCWRITE(hio)) {
1816 			if (!hio->hio_memsyncacked) {
1817 				PJDLOG_ASSERT(memsyncack ||
1818 				    hio->hio_errors[ncomp] != 0);
1819 				/* Remote ack arrived. */
1820 				if (refcnt_release(&hio->hio_writecount) == 0) {
1821 					if (hio->hio_errors[0] == 0)
1822 						write_complete(res, hio);
1823 				}
1824 				hio->hio_memsyncacked = true;
1825 				if (hio->hio_errors[ncomp] == 0) {
1826 					pjdlog_debug(2,
1827 					    "remote_recv: (%p) Moving request "
1828 					    "back to the recv queue.", hio);
1829 					mtx_lock(&hio_recv_list_lock[ncomp]);
1830 					TAILQ_INSERT_TAIL(&hio_recv_list[ncomp],
1831 					    hio, hio_next[ncomp]);
1832 					hio_recv_list_size[ncomp]++;
1833 					mtx_unlock(&hio_recv_list_lock[ncomp]);
1834 					continue;
1835 				}
1836 			} else {
1837 				PJDLOG_ASSERT(!memsyncack);
1838 				/* Remote final reply arrived. */
1839 			}
1840 		}
1841 		if (refcnt_release(&hio->hio_countdown) > 0)
1842 			continue;
1843 		if (ISSYNCREQ(hio)) {
1844 			mtx_lock(&sync_lock);
1845 			SYNCREQDONE(hio);
1846 			mtx_unlock(&sync_lock);
1847 			cv_signal(&sync_cond);
1848 		} else {
1849 			pjdlog_debug(2,
1850 			    "remote_recv: (%p) Moving request to the done queue.",
1851 			    hio);
1852 			QUEUE_INSERT2(hio, done);
1853 		}
1854 	}
1855 	/* NOTREACHED */
1856 	return (NULL);
1857 }
1858 
1859 /*
1860  * Thread sends answer to the kernel.
1861  */
1862 static void *
1863 ggate_send_thread(void *arg)
1864 {
1865 	struct hast_resource *res = arg;
1866 	struct g_gate_ctl_io *ggio;
1867 	struct hio *hio;
1868 	unsigned int ii, ncomps;
1869 
1870 	ncomps = HAST_NCOMPONENTS;
1871 
1872 	for (;;) {
1873 		pjdlog_debug(2, "ggate_send: Taking request.");
1874 		QUEUE_TAKE2(hio, done);
1875 		pjdlog_debug(2, "ggate_send: (%p) Got request.", hio);
1876 		ggio = &hio->hio_ggio;
1877 		for (ii = 0; ii < ncomps; ii++) {
1878 			if (hio->hio_errors[ii] == 0) {
1879 				/*
1880 				 * One successful request is enough to declare
1881 				 * success.
1882 				 */
1883 				ggio->gctl_error = 0;
1884 				break;
1885 			}
1886 		}
1887 		if (ii == ncomps) {
1888 			/*
1889 			 * None of the requests were successful.
1890 			 * Use the error from local component except the
1891 			 * case when we did only remote request.
1892 			 */
1893 			if (ggio->gctl_cmd == BIO_READ &&
1894 			    res->hr_syncsrc == HAST_SYNCSRC_SECONDARY)
1895 				ggio->gctl_error = hio->hio_errors[1];
1896 			else
1897 				ggio->gctl_error = hio->hio_errors[0];
1898 		}
1899 		if (ggio->gctl_error == 0 && ggio->gctl_cmd == BIO_WRITE) {
1900 			mtx_lock(&res->hr_amp_lock);
1901 			if (activemap_write_complete(res->hr_amp,
1902 			    ggio->gctl_offset, ggio->gctl_length)) {
1903 				res->hr_stat_activemap_update++;
1904 				(void)hast_activemap_flush(res);
1905 			} else {
1906 				mtx_unlock(&res->hr_amp_lock);
1907 			}
1908 		}
1909 		if (ggio->gctl_cmd == BIO_WRITE) {
1910 			/*
1911 			 * Unlock range we locked.
1912 			 */
1913 			mtx_lock(&range_lock);
1914 			rangelock_del(range_regular, ggio->gctl_offset,
1915 			    ggio->gctl_length);
1916 			if (range_sync_wait)
1917 				cv_signal(&range_sync_cond);
1918 			mtx_unlock(&range_lock);
1919 			if (!hio->hio_done)
1920 				write_complete(res, hio);
1921 		} else {
1922 			if (ioctl(res->hr_ggatefd, G_GATE_CMD_DONE, ggio) == -1) {
1923 				primary_exit(EX_OSERR,
1924 				    "G_GATE_CMD_DONE failed");
1925 			}
1926 		}
1927 		if (hio->hio_errors[0]) {
1928 			switch (ggio->gctl_cmd) {
1929 			case BIO_READ:
1930 				res->hr_stat_read_error++;
1931 				break;
1932 			case BIO_WRITE:
1933 				res->hr_stat_write_error++;
1934 				break;
1935 			case BIO_DELETE:
1936 				res->hr_stat_delete_error++;
1937 				break;
1938 			case BIO_FLUSH:
1939 				res->hr_stat_flush_error++;
1940 				break;
1941 			}
1942 		}
1943 		pjdlog_debug(2,
1944 		    "ggate_send: (%p) Moving request to the free queue.", hio);
1945 		QUEUE_INSERT2(hio, free);
1946 	}
1947 	/* NOTREACHED */
1948 	return (NULL);
1949 }
1950 
1951 /*
1952  * Thread synchronize local and remote components.
1953  */
1954 static void *
1955 sync_thread(void *arg __unused)
1956 {
1957 	struct hast_resource *res = arg;
1958 	struct hio *hio;
1959 	struct g_gate_ctl_io *ggio;
1960 	struct timeval tstart, tend, tdiff;
1961 	unsigned int ii, ncomp, ncomps;
1962 	off_t offset, length, synced;
1963 	bool dorewind, directreads;
1964 	int syncext;
1965 
1966 	ncomps = HAST_NCOMPONENTS;
1967 	dorewind = true;
1968 	synced = 0;
1969 	offset = -1;
1970 	directreads = false;
1971 
1972 	for (;;) {
1973 		mtx_lock(&sync_lock);
1974 		if (offset >= 0 && !sync_inprogress) {
1975 			gettimeofday(&tend, NULL);
1976 			timersub(&tend, &tstart, &tdiff);
1977 			pjdlog_info("Synchronization interrupted after %#.0T. "
1978 			    "%NB synchronized so far.", &tdiff,
1979 			    (intmax_t)synced);
1980 			event_send(res, EVENT_SYNCINTR);
1981 		}
1982 		while (!sync_inprogress) {
1983 			dorewind = true;
1984 			synced = 0;
1985 			cv_wait(&sync_cond, &sync_lock);
1986 		}
1987 		mtx_unlock(&sync_lock);
1988 		/*
1989 		 * Obtain offset at which we should synchronize.
1990 		 * Rewind synchronization if needed.
1991 		 */
1992 		mtx_lock(&res->hr_amp_lock);
1993 		if (dorewind)
1994 			activemap_sync_rewind(res->hr_amp);
1995 		offset = activemap_sync_offset(res->hr_amp, &length, &syncext);
1996 		if (syncext != -1) {
1997 			/*
1998 			 * We synchronized entire syncext extent, we can mark
1999 			 * it as clean now.
2000 			 */
2001 			if (activemap_extent_complete(res->hr_amp, syncext))
2002 				(void)hast_activemap_flush(res);
2003 			else
2004 				mtx_unlock(&res->hr_amp_lock);
2005 		} else {
2006 			mtx_unlock(&res->hr_amp_lock);
2007 		}
2008 		if (dorewind) {
2009 			dorewind = false;
2010 			if (offset == -1)
2011 				pjdlog_info("Nodes are in sync.");
2012 			else {
2013 				pjdlog_info("Synchronization started. %NB to go.",
2014 				    (intmax_t)(res->hr_extentsize *
2015 				    activemap_ndirty(res->hr_amp)));
2016 				event_send(res, EVENT_SYNCSTART);
2017 				gettimeofday(&tstart, NULL);
2018 			}
2019 		}
2020 		if (offset == -1) {
2021 			sync_stop();
2022 			pjdlog_debug(1, "Nothing to synchronize.");
2023 			/*
2024 			 * Synchronization complete, make both localcnt and
2025 			 * remotecnt equal.
2026 			 */
2027 			ncomp = 1;
2028 			rw_rlock(&hio_remote_lock[ncomp]);
2029 			if (ISCONNECTED(res, ncomp)) {
2030 				if (synced > 0) {
2031 					int64_t bps;
2032 
2033 					gettimeofday(&tend, NULL);
2034 					timersub(&tend, &tstart, &tdiff);
2035 					bps = (int64_t)((double)synced /
2036 					    ((double)tdiff.tv_sec +
2037 					    (double)tdiff.tv_usec / 1000000));
2038 					pjdlog_info("Synchronization complete. "
2039 					    "%NB synchronized in %#.0lT (%NB/sec).",
2040 					    (intmax_t)synced, &tdiff,
2041 					    (intmax_t)bps);
2042 					event_send(res, EVENT_SYNCDONE);
2043 				}
2044 				mtx_lock(&metadata_lock);
2045 				if (res->hr_syncsrc == HAST_SYNCSRC_SECONDARY)
2046 					directreads = true;
2047 				res->hr_syncsrc = HAST_SYNCSRC_UNDEF;
2048 				res->hr_primary_localcnt =
2049 				    res->hr_secondary_remotecnt;
2050 				res->hr_primary_remotecnt =
2051 				    res->hr_secondary_localcnt;
2052 				pjdlog_debug(1,
2053 				    "Setting localcnt to %ju and remotecnt to %ju.",
2054 				    (uintmax_t)res->hr_primary_localcnt,
2055 				    (uintmax_t)res->hr_primary_remotecnt);
2056 				(void)metadata_write(res);
2057 				mtx_unlock(&metadata_lock);
2058 			}
2059 			rw_unlock(&hio_remote_lock[ncomp]);
2060 			if (directreads) {
2061 				directreads = false;
2062 				enable_direct_reads(res);
2063 			}
2064 			continue;
2065 		}
2066 		pjdlog_debug(2, "sync: Taking free request.");
2067 		QUEUE_TAKE2(hio, free);
2068 		pjdlog_debug(2, "sync: (%p) Got free request.", hio);
2069 		/*
2070 		 * Lock the range we are going to synchronize. We don't want
2071 		 * race where someone writes between our read and write.
2072 		 */
2073 		for (;;) {
2074 			mtx_lock(&range_lock);
2075 			if (rangelock_islocked(range_regular, offset, length)) {
2076 				pjdlog_debug(2,
2077 				    "sync: Range offset=%jd length=%jd locked.",
2078 				    (intmax_t)offset, (intmax_t)length);
2079 				range_sync_wait = true;
2080 				cv_wait(&range_sync_cond, &range_lock);
2081 				range_sync_wait = false;
2082 				mtx_unlock(&range_lock);
2083 				continue;
2084 			}
2085 			if (rangelock_add(range_sync, offset, length) == -1) {
2086 				mtx_unlock(&range_lock);
2087 				pjdlog_debug(2,
2088 				    "sync: Range offset=%jd length=%jd is already locked, waiting.",
2089 				    (intmax_t)offset, (intmax_t)length);
2090 				sleep(1);
2091 				continue;
2092 			}
2093 			mtx_unlock(&range_lock);
2094 			break;
2095 		}
2096 		/*
2097 		 * First read the data from synchronization source.
2098 		 */
2099 		SYNCREQ(hio);
2100 		ggio = &hio->hio_ggio;
2101 		ggio->gctl_cmd = BIO_READ;
2102 		ggio->gctl_offset = offset;
2103 		ggio->gctl_length = length;
2104 		ggio->gctl_error = 0;
2105 		hio->hio_done = false;
2106 		hio->hio_replication = res->hr_replication;
2107 		for (ii = 0; ii < ncomps; ii++)
2108 			hio->hio_errors[ii] = EINVAL;
2109 		reqlog(LOG_DEBUG, 2, ggio, "sync: (%p) Sending sync request: ",
2110 		    hio);
2111 		pjdlog_debug(2, "sync: (%p) Moving request to the send queue.",
2112 		    hio);
2113 		mtx_lock(&metadata_lock);
2114 		if (res->hr_syncsrc == HAST_SYNCSRC_PRIMARY) {
2115 			/*
2116 			 * This range is up-to-date on local component,
2117 			 * so handle request locally.
2118 			 */
2119 			 /* Local component is 0 for now. */
2120 			ncomp = 0;
2121 		} else /* if (res->hr_syncsrc == HAST_SYNCSRC_SECONDARY) */ {
2122 			PJDLOG_ASSERT(res->hr_syncsrc == HAST_SYNCSRC_SECONDARY);
2123 			/*
2124 			 * This range is out-of-date on local component,
2125 			 * so send request to the remote node.
2126 			 */
2127 			 /* Remote component is 1 for now. */
2128 			ncomp = 1;
2129 		}
2130 		mtx_unlock(&metadata_lock);
2131 		refcnt_init(&hio->hio_countdown, 1);
2132 		QUEUE_INSERT1(hio, send, ncomp);
2133 
2134 		/*
2135 		 * Let's wait for READ to finish.
2136 		 */
2137 		mtx_lock(&sync_lock);
2138 		while (!ISSYNCREQDONE(hio))
2139 			cv_wait(&sync_cond, &sync_lock);
2140 		mtx_unlock(&sync_lock);
2141 
2142 		if (hio->hio_errors[ncomp] != 0) {
2143 			pjdlog_error("Unable to read synchronization data: %s.",
2144 			    strerror(hio->hio_errors[ncomp]));
2145 			goto free_queue;
2146 		}
2147 
2148 		/*
2149 		 * We read the data from synchronization source, now write it
2150 		 * to synchronization target.
2151 		 */
2152 		SYNCREQ(hio);
2153 		ggio->gctl_cmd = BIO_WRITE;
2154 		for (ii = 0; ii < ncomps; ii++)
2155 			hio->hio_errors[ii] = EINVAL;
2156 		reqlog(LOG_DEBUG, 2, ggio, "sync: (%p) Sending sync request: ",
2157 		    hio);
2158 		pjdlog_debug(2, "sync: (%p) Moving request to the send queue.",
2159 		    hio);
2160 		mtx_lock(&metadata_lock);
2161 		if (res->hr_syncsrc == HAST_SYNCSRC_PRIMARY) {
2162 			/*
2163 			 * This range is up-to-date on local component,
2164 			 * so we update remote component.
2165 			 */
2166 			 /* Remote component is 1 for now. */
2167 			ncomp = 1;
2168 		} else /* if (res->hr_syncsrc == HAST_SYNCSRC_SECONDARY) */ {
2169 			PJDLOG_ASSERT(res->hr_syncsrc == HAST_SYNCSRC_SECONDARY);
2170 			/*
2171 			 * This range is out-of-date on local component,
2172 			 * so we update it.
2173 			 */
2174 			 /* Local component is 0 for now. */
2175 			ncomp = 0;
2176 		}
2177 		mtx_unlock(&metadata_lock);
2178 
2179 		pjdlog_debug(2, "sync: (%p) Moving request to the send queue.",
2180 		    hio);
2181 		refcnt_init(&hio->hio_countdown, 1);
2182 		QUEUE_INSERT1(hio, send, ncomp);
2183 
2184 		/*
2185 		 * Let's wait for WRITE to finish.
2186 		 */
2187 		mtx_lock(&sync_lock);
2188 		while (!ISSYNCREQDONE(hio))
2189 			cv_wait(&sync_cond, &sync_lock);
2190 		mtx_unlock(&sync_lock);
2191 
2192 		if (hio->hio_errors[ncomp] != 0) {
2193 			pjdlog_error("Unable to write synchronization data: %s.",
2194 			    strerror(hio->hio_errors[ncomp]));
2195 			goto free_queue;
2196 		}
2197 
2198 		synced += length;
2199 free_queue:
2200 		mtx_lock(&range_lock);
2201 		rangelock_del(range_sync, offset, length);
2202 		if (range_regular_wait)
2203 			cv_signal(&range_regular_cond);
2204 		mtx_unlock(&range_lock);
2205 		pjdlog_debug(2, "sync: (%p) Moving request to the free queue.",
2206 		    hio);
2207 		QUEUE_INSERT2(hio, free);
2208 	}
2209 	/* NOTREACHED */
2210 	return (NULL);
2211 }
2212 
2213 void
2214 primary_config_reload(struct hast_resource *res, struct nv *nv)
2215 {
2216 	unsigned int ii, ncomps;
2217 	int modified, vint;
2218 	const char *vstr;
2219 
2220 	pjdlog_info("Reloading configuration...");
2221 
2222 	PJDLOG_ASSERT(res->hr_role == HAST_ROLE_PRIMARY);
2223 	PJDLOG_ASSERT(gres == res);
2224 	nv_assert(nv, "remoteaddr");
2225 	nv_assert(nv, "sourceaddr");
2226 	nv_assert(nv, "replication");
2227 	nv_assert(nv, "checksum");
2228 	nv_assert(nv, "compression");
2229 	nv_assert(nv, "timeout");
2230 	nv_assert(nv, "exec");
2231 	nv_assert(nv, "metaflush");
2232 
2233 	ncomps = HAST_NCOMPONENTS;
2234 
2235 #define MODIFIED_REMOTEADDR	0x01
2236 #define MODIFIED_SOURCEADDR	0x02
2237 #define MODIFIED_REPLICATION	0x04
2238 #define MODIFIED_CHECKSUM	0x08
2239 #define MODIFIED_COMPRESSION	0x10
2240 #define MODIFIED_TIMEOUT	0x20
2241 #define MODIFIED_EXEC		0x40
2242 #define MODIFIED_METAFLUSH	0x80
2243 	modified = 0;
2244 
2245 	vstr = nv_get_string(nv, "remoteaddr");
2246 	if (strcmp(gres->hr_remoteaddr, vstr) != 0) {
2247 		/*
2248 		 * Don't copy res->hr_remoteaddr to gres just yet.
2249 		 * We want remote_close() to log disconnect from the old
2250 		 * addresses, not from the new ones.
2251 		 */
2252 		modified |= MODIFIED_REMOTEADDR;
2253 	}
2254 	vstr = nv_get_string(nv, "sourceaddr");
2255 	if (strcmp(gres->hr_sourceaddr, vstr) != 0) {
2256 		strlcpy(gres->hr_sourceaddr, vstr, sizeof(gres->hr_sourceaddr));
2257 		modified |= MODIFIED_SOURCEADDR;
2258 	}
2259 	vint = nv_get_int32(nv, "replication");
2260 	if (gres->hr_replication != vint) {
2261 		gres->hr_replication = vint;
2262 		modified |= MODIFIED_REPLICATION;
2263 	}
2264 	vint = nv_get_int32(nv, "checksum");
2265 	if (gres->hr_checksum != vint) {
2266 		gres->hr_checksum = vint;
2267 		modified |= MODIFIED_CHECKSUM;
2268 	}
2269 	vint = nv_get_int32(nv, "compression");
2270 	if (gres->hr_compression != vint) {
2271 		gres->hr_compression = vint;
2272 		modified |= MODIFIED_COMPRESSION;
2273 	}
2274 	vint = nv_get_int32(nv, "timeout");
2275 	if (gres->hr_timeout != vint) {
2276 		gres->hr_timeout = vint;
2277 		modified |= MODIFIED_TIMEOUT;
2278 	}
2279 	vstr = nv_get_string(nv, "exec");
2280 	if (strcmp(gres->hr_exec, vstr) != 0) {
2281 		strlcpy(gres->hr_exec, vstr, sizeof(gres->hr_exec));
2282 		modified |= MODIFIED_EXEC;
2283 	}
2284 	vint = nv_get_int32(nv, "metaflush");
2285 	if (gres->hr_metaflush != vint) {
2286 		gres->hr_metaflush = vint;
2287 		modified |= MODIFIED_METAFLUSH;
2288 	}
2289 
2290 	/*
2291 	 * Change timeout for connected sockets.
2292 	 * Don't bother if we need to reconnect.
2293 	 */
2294 	if ((modified & MODIFIED_TIMEOUT) != 0 &&
2295 	    (modified & (MODIFIED_REMOTEADDR | MODIFIED_SOURCEADDR)) == 0) {
2296 		for (ii = 0; ii < ncomps; ii++) {
2297 			if (!ISREMOTE(ii))
2298 				continue;
2299 			rw_rlock(&hio_remote_lock[ii]);
2300 			if (!ISCONNECTED(gres, ii)) {
2301 				rw_unlock(&hio_remote_lock[ii]);
2302 				continue;
2303 			}
2304 			rw_unlock(&hio_remote_lock[ii]);
2305 			if (proto_timeout(gres->hr_remotein,
2306 			    gres->hr_timeout) == -1) {
2307 				pjdlog_errno(LOG_WARNING,
2308 				    "Unable to set connection timeout");
2309 			}
2310 			if (proto_timeout(gres->hr_remoteout,
2311 			    gres->hr_timeout) == -1) {
2312 				pjdlog_errno(LOG_WARNING,
2313 				    "Unable to set connection timeout");
2314 			}
2315 		}
2316 	}
2317 	if ((modified & (MODIFIED_REMOTEADDR | MODIFIED_SOURCEADDR)) != 0) {
2318 		for (ii = 0; ii < ncomps; ii++) {
2319 			if (!ISREMOTE(ii))
2320 				continue;
2321 			remote_close(gres, ii);
2322 		}
2323 		if (modified & MODIFIED_REMOTEADDR) {
2324 			vstr = nv_get_string(nv, "remoteaddr");
2325 			strlcpy(gres->hr_remoteaddr, vstr,
2326 			    sizeof(gres->hr_remoteaddr));
2327 		}
2328 	}
2329 #undef	MODIFIED_REMOTEADDR
2330 #undef	MODIFIED_SOURCEADDR
2331 #undef	MODIFIED_REPLICATION
2332 #undef	MODIFIED_CHECKSUM
2333 #undef	MODIFIED_COMPRESSION
2334 #undef	MODIFIED_TIMEOUT
2335 #undef	MODIFIED_EXEC
2336 #undef	MODIFIED_METAFLUSH
2337 
2338 	pjdlog_info("Configuration reloaded successfully.");
2339 }
2340 
2341 static void
2342 guard_one(struct hast_resource *res, unsigned int ncomp)
2343 {
2344 	struct proto_conn *in, *out;
2345 
2346 	if (!ISREMOTE(ncomp))
2347 		return;
2348 
2349 	rw_rlock(&hio_remote_lock[ncomp]);
2350 
2351 	if (!real_remote(res)) {
2352 		rw_unlock(&hio_remote_lock[ncomp]);
2353 		return;
2354 	}
2355 
2356 	if (ISCONNECTED(res, ncomp)) {
2357 		PJDLOG_ASSERT(res->hr_remotein != NULL);
2358 		PJDLOG_ASSERT(res->hr_remoteout != NULL);
2359 		rw_unlock(&hio_remote_lock[ncomp]);
2360 		pjdlog_debug(2, "remote_guard: Connection to %s is ok.",
2361 		    res->hr_remoteaddr);
2362 		return;
2363 	}
2364 
2365 	PJDLOG_ASSERT(res->hr_remotein == NULL);
2366 	PJDLOG_ASSERT(res->hr_remoteout == NULL);
2367 	/*
2368 	 * Upgrade the lock. It doesn't have to be atomic as no other thread
2369 	 * can change connection status from disconnected to connected.
2370 	 */
2371 	rw_unlock(&hio_remote_lock[ncomp]);
2372 	pjdlog_debug(2, "remote_guard: Reconnecting to %s.",
2373 	    res->hr_remoteaddr);
2374 	in = out = NULL;
2375 	if (init_remote(res, &in, &out) == 0) {
2376 		rw_wlock(&hio_remote_lock[ncomp]);
2377 		PJDLOG_ASSERT(res->hr_remotein == NULL);
2378 		PJDLOG_ASSERT(res->hr_remoteout == NULL);
2379 		PJDLOG_ASSERT(in != NULL && out != NULL);
2380 		res->hr_remotein = in;
2381 		res->hr_remoteout = out;
2382 		rw_unlock(&hio_remote_lock[ncomp]);
2383 		pjdlog_info("Successfully reconnected to %s.",
2384 		    res->hr_remoteaddr);
2385 		sync_start();
2386 	} else {
2387 		/* Both connections should be NULL. */
2388 		PJDLOG_ASSERT(res->hr_remotein == NULL);
2389 		PJDLOG_ASSERT(res->hr_remoteout == NULL);
2390 		PJDLOG_ASSERT(in == NULL && out == NULL);
2391 		pjdlog_debug(2, "remote_guard: Reconnect to %s failed.",
2392 		    res->hr_remoteaddr);
2393 	}
2394 }
2395 
2396 /*
2397  * Thread guards remote connections and reconnects when needed, handles
2398  * signals, etc.
2399  */
2400 static void *
2401 guard_thread(void *arg)
2402 {
2403 	struct hast_resource *res = arg;
2404 	unsigned int ii, ncomps;
2405 	struct timespec timeout;
2406 	time_t lastcheck, now;
2407 	sigset_t mask;
2408 	int signo;
2409 
2410 	ncomps = HAST_NCOMPONENTS;
2411 	lastcheck = time(NULL);
2412 
2413 	PJDLOG_VERIFY(sigemptyset(&mask) == 0);
2414 	PJDLOG_VERIFY(sigaddset(&mask, SIGINT) == 0);
2415 	PJDLOG_VERIFY(sigaddset(&mask, SIGTERM) == 0);
2416 
2417 	timeout.tv_sec = HAST_KEEPALIVE;
2418 	timeout.tv_nsec = 0;
2419 	signo = -1;
2420 
2421 	for (;;) {
2422 		switch (signo) {
2423 		case SIGINT:
2424 		case SIGTERM:
2425 			sigexit_received = true;
2426 			primary_exitx(EX_OK,
2427 			    "Termination signal received, exiting.");
2428 			break;
2429 		default:
2430 			break;
2431 		}
2432 
2433 		/*
2434 		 * Don't check connections until we fully started,
2435 		 * as we may still be looping, waiting for remote node
2436 		 * to switch from primary to secondary.
2437 		 */
2438 		if (fullystarted) {
2439 			pjdlog_debug(2, "remote_guard: Checking connections.");
2440 			now = time(NULL);
2441 			if (lastcheck + HAST_KEEPALIVE <= now) {
2442 				for (ii = 0; ii < ncomps; ii++)
2443 					guard_one(res, ii);
2444 				lastcheck = now;
2445 			}
2446 		}
2447 		signo = sigtimedwait(&mask, NULL, &timeout);
2448 	}
2449 	/* NOTREACHED */
2450 	return (NULL);
2451 }
2452