sbin/hastd/primary.c

   1 /*-
   2  * Copyright (c) 2009 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/types.h>
  35 #include <sys/time.h>
  36 #include <sys/bio.h>
  37 #include <sys/disk.h>
  38 #include <sys/refcount.h>
  39 #include <sys/stat.h>
  40
  41 #include <geom/gate/g_gate.h>
  42
  43 #include <assert.h>
  44 #include <err.h>
  45 #include <errno.h>
  46 #include <fcntl.h>
  47 #include <libgeom.h>
  48 #include <pthread.h>
  49 #include <signal.h>
  50 #include <stdint.h>
  51 #include <stdio.h>
  52 #include <string.h>
  53 #include <sysexits.h>
  54 #include <unistd.h>
  55
  56 #include <activemap.h>
  57 #include <nv.h>
  58 #include <rangelock.h>
  59
  60 #include "control.h"
  61 #include "event.h"
  62 #include "hast.h"
  63 #include "hast_proto.h"
  64 #include "hastd.h"
  65 #include "hooks.h"
  66 #include "metadata.h"
  67 #include "proto.h"
  68 #include "pjdlog.h"
  69 #include "subr.h"
  70 #include "synch.h"
  71
  72 /* The is only one remote component for now. */
  73 #define ISREMOTE(no)    ((no) == 1)
  74
  75 struct hio {
  76         /*
  77          * Number of components we are still waiting for.
  78          * When this field goes to 0, we can send the request back to the
  79          * kernel. Each component has to decrease this counter by one
  80          * even on failure.
  81          */
  82         unsigned int             hio_countdown;
  83         /*
  84          * Each component has a place to store its own error.
  85          * Once the request is handled by all components we can decide if the
  86          * request overall is successful or not.
  87          */
  88         int                     *hio_errors;
  89         /*
  90          * Structure used to comunicate with GEOM Gate class.
  91          */
  92         struct g_gate_ctl_io     hio_ggio;
  93         TAILQ_ENTRY(hio)        *hio_next;
  94 };
  95 #define hio_free_next   hio_next[0]
  96 #define hio_done_next   hio_next[0]
  97
  98 /*
  99  * Free list holds unused structures. When free list is empty, we have to wait
 100  * until some in-progress requests are freed.
 101  */
 102 static TAILQ_HEAD(, hio) hio_free_list;
 103 static pthread_mutex_t hio_free_list_lock;
 104 static pthread_cond_t hio_free_list_cond;
 105 /*
 106  * There is one send list for every component. One requests is placed on all
 107  * send lists - each component gets the same request, but each component is
 108  * responsible for managing his own send list.
 109  */
 110 static TAILQ_HEAD(, hio) *hio_send_list;
 111 static pthread_mutex_t *hio_send_list_lock;
 112 static pthread_cond_t *hio_send_list_cond;
 113 /*
 114  * There is one recv list for every component, although local components don't
 115  * use recv lists as local requests are done synchronously.
 116  */
 117 static TAILQ_HEAD(, hio) *hio_recv_list;
 118 static pthread_mutex_t *hio_recv_list_lock;
 119 static pthread_cond_t *hio_recv_list_cond;
 120 /*
 121  * Request is placed on done list by the slowest component (the one that
 122  * decreased hio_countdown from 1 to 0).
 123  */
 124 static TAILQ_HEAD(, hio) hio_done_list;
 125 static pthread_mutex_t hio_done_list_lock;
 126 static pthread_cond_t hio_done_list_cond;
 127 /*
 128  * Structure below are for interaction with sync thread.
 129  */
 130 static bool sync_inprogress;
 131 static pthread_mutex_t sync_lock;
 132 static pthread_cond_t sync_cond;
 133 /*
 134  * The lock below allows to synchornize access to remote connections.
 135  */
 136 static pthread_rwlock_t *hio_remote_lock;
 137
 138 /*
 139  * Lock to synchronize metadata updates. Also synchronize access to
 140  * hr_primary_localcnt and hr_primary_remotecnt fields.
 141  */
 142 static pthread_mutex_t metadata_lock;
 143
 144 /*
 145  * Maximum number of outstanding I/O requests.
 146  */
 147 #define HAST_HIO_MAX    256
 148 /*
 149  * Number of components. At this point there are only two components: local
 150  * and remote, but in the future it might be possible to use multiple local
 151  * and remote components.
 152  */
 153 #define HAST_NCOMPONENTS        2
 154 /*
 155  * Number of seconds to sleep between reconnect retries or keepalive packets.
 156  */
 157 #define RETRY_SLEEP             10
 158
 159 #define ISCONNECTED(res, no)    \
 160         ((res)->hr_remotein != NULL && (res)->hr_remoteout != NULL)
 161
 162 #define QUEUE_INSERT1(hio, name, ncomp) do {                            \
 163         bool _wakeup;                                                   \
 164                                                                         \
 165         mtx_lock(&hio_##name##_list_lock[(ncomp)]);                     \
 166         _wakeup = TAILQ_EMPTY(&hio_##name##_list[(ncomp)]);             \
 167         TAILQ_INSERT_TAIL(&hio_##name##_list[(ncomp)], (hio),           \
 168             hio_next[(ncomp)]);                                         \
 169         mtx_unlock(&hio_##name##_list_lock[ncomp]);                     \
 170         if (_wakeup)                                                    \
 171                 cv_signal(&hio_##name##_list_cond[(ncomp)]);            \
 172 } while (0)
 173 #define QUEUE_INSERT2(hio, name)        do {                            \
 174         bool _wakeup;                                                   \
 175                                                                         \
 176         mtx_lock(&hio_##name##_list_lock);                              \
 177         _wakeup = TAILQ_EMPTY(&hio_##name##_list);                      \
 178         TAILQ_INSERT_TAIL(&hio_##name##_list, (hio), hio_##name##_next);\
 179         mtx_unlock(&hio_##name##_list_lock);                            \
 180         if (_wakeup)                                                    \
 181                 cv_signal(&hio_##name##_list_cond);                     \
 182 } while (0)
 183 #define QUEUE_TAKE1(hio, name, ncomp)   do {                            \
 184         mtx_lock(&hio_##name##_list_lock[(ncomp)]);                     \
 185         while (((hio) = TAILQ_FIRST(&hio_##name##_list[(ncomp)])) == NULL) { \
 186                 cv_wait(&hio_##name##_list_cond[(ncomp)],               \
 187                     &hio_##name##_list_lock[(ncomp)]);                  \
 188         }                                                               \
 189         TAILQ_REMOVE(&hio_##name##_list[(ncomp)], (hio),                \
 190             hio_next[(ncomp)]);                                         \
 191         mtx_unlock(&hio_##name##_list_lock[(ncomp)]);                   \
 192 } while (0)
 193 #define QUEUE_TAKE2(hio, name)  do {                                    \
 194         mtx_lock(&hio_##name##_list_lock);                              \
 195         while (((hio) = TAILQ_FIRST(&hio_##name##_list)) == NULL) {     \
 196                 cv_wait(&hio_##name##_list_cond,                        \
 197                     &hio_##name##_list_lock);                           \
 198         }                                                               \
 199         TAILQ_REMOVE(&hio_##name##_list, (hio), hio_##name##_next);     \
 200         mtx_unlock(&hio_##name##_list_lock);                            \
 201 } while (0)
 202
 203 #define SYNCREQ(hio)            do {                                    \
 204         (hio)->hio_ggio.gctl_unit = -1;                                 \
 205         (hio)->hio_ggio.gctl_seq = 1;                                   \
 206 } while (0)
 207 #define ISSYNCREQ(hio)          ((hio)->hio_ggio.gctl_unit == -1)
 208 #define SYNCREQDONE(hio)        do { (hio)->hio_ggio.gctl_unit = -2; } while (0)
 209 #define ISSYNCREQDONE(hio)      ((hio)->hio_ggio.gctl_unit == -2)
 210
 211 static struct hast_resource *gres;
 212
 213 static pthread_mutex_t range_lock;
 214 static struct rangelocks *range_regular;
 215 static bool range_regular_wait;
 216 static pthread_cond_t range_regular_cond;
 217 static struct rangelocks *range_sync;
 218 static bool range_sync_wait;
 219 static pthread_cond_t range_sync_cond;
 220
 221 static void *ggate_recv_thread(void *arg);
 222 static void *local_send_thread(void *arg);
 223 static void *remote_send_thread(void *arg);
 224 static void *remote_recv_thread(void *arg);
 225 static void *ggate_send_thread(void *arg);
 226 static void *sync_thread(void *arg);
 227 static void *guard_thread(void *arg);
 228
 229 static void
 230 cleanup(struct hast_resource *res)
 231 {
 232         int rerrno;
 233
 234         /* Remember errno. */
 235         rerrno = errno;
 236
 237         /* Destroy ggate provider if we created one. */
 238         if (res->hr_ggateunit >= 0) {
 239                 struct g_gate_ctl_destroy ggiod;
 240
 241                 bzero(&ggiod, sizeof(ggiod));
 242                 ggiod.gctl_version = G_GATE_VERSION;
 243                 ggiod.gctl_unit = res->hr_ggateunit;
 244                 ggiod.gctl_force = 1;
 245                 if (ioctl(res->hr_ggatefd, G_GATE_CMD_DESTROY, &ggiod) < 0) {
 246                         pjdlog_errno(LOG_WARNING,
 247                             "Unable to destroy hast/%s device",
 248                             res->hr_provname);
 249                 }
 250                 res->hr_ggateunit = -1;
 251         }
 252
 253         /* Restore errno. */
 254         errno = rerrno;
 255 }
 256
 257 static __dead2 void
 258 primary_exit(int exitcode, const char *fmt, ...)
 259 {
 260         va_list ap;
 261
 262         assert(exitcode != EX_OK);
 263         va_start(ap, fmt);
 264         pjdlogv_errno(LOG_ERR, fmt, ap);
 265         va_end(ap);
 266         cleanup(gres);
 267         exit(exitcode);
 268 }
 269
 270 static __dead2 void
 271 primary_exitx(int exitcode, const char *fmt, ...)
 272 {
 273         va_list ap;
 274
 275         va_start(ap, fmt);
 276         pjdlogv(exitcode == EX_OK ? LOG_INFO : LOG_ERR, fmt, ap);
 277         va_end(ap);
 278         cleanup(gres);
 279         exit(exitcode);
 280 }
 281
 282 static int
 283 hast_activemap_flush(struct hast_resource *res)
 284 {
 285         const unsigned char *buf;
 286         size_t size;
 287
 288         buf = activemap_bitmap(res->hr_amp, &size);
 289         assert(buf != NULL);
 290         assert((size % res->hr_local_sectorsize) == 0);
 291         if (pwrite(res->hr_localfd, buf, size, METADATA_SIZE) !=
 292             (ssize_t)size) {
 293                 KEEP_ERRNO(pjdlog_errno(LOG_ERR,
 294                     "Unable to flush activemap to disk"));
 295                 return (-1);
 296         }
 297         return (0);
 298 }
 299
 300 static bool
 301 real_remote(const struct hast_resource *res)
 302 {
 303
 304         return (strcmp(res->hr_remoteaddr, "none") != 0);
 305 }
 306
 307 static void
 308 init_environment(struct hast_resource *res __unused)
 309 {
 310         struct hio *hio;
 311         unsigned int ii, ncomps;
 312
 313         /*
 314          * In the future it might be per-resource value.
 315          */
 316         ncomps = HAST_NCOMPONENTS;
 317
 318         /*
 319          * Allocate memory needed by lists.
 320          */
 321         hio_send_list = malloc(sizeof(hio_send_list[0]) * ncomps);
 322         if (hio_send_list == NULL) {
 323                 primary_exitx(EX_TEMPFAIL,
 324                     "Unable to allocate %zu bytes of memory for send lists.",
 325                     sizeof(hio_send_list[0]) * ncomps);
 326         }
 327         hio_send_list_lock = malloc(sizeof(hio_send_list_lock[0]) * ncomps);
 328         if (hio_send_list_lock == NULL) {
 329                 primary_exitx(EX_TEMPFAIL,
 330                     "Unable to allocate %zu bytes of memory for send list locks.",
 331                     sizeof(hio_send_list_lock[0]) * ncomps);
 332         }
 333         hio_send_list_cond = malloc(sizeof(hio_send_list_cond[0]) * ncomps);
 334         if (hio_send_list_cond == NULL) {
 335                 primary_exitx(EX_TEMPFAIL,
 336                     "Unable to allocate %zu bytes of memory for send list condition variables.",
 337                     sizeof(hio_send_list_cond[0]) * ncomps);
 338         }
 339         hio_recv_list = malloc(sizeof(hio_recv_list[0]) * ncomps);
 340         if (hio_recv_list == NULL) {
 341                 primary_exitx(EX_TEMPFAIL,
 342                     "Unable to allocate %zu bytes of memory for recv lists.",
 343                     sizeof(hio_recv_list[0]) * ncomps);
 344         }
 345         hio_recv_list_lock = malloc(sizeof(hio_recv_list_lock[0]) * ncomps);
 346         if (hio_recv_list_lock == NULL) {
 347                 primary_exitx(EX_TEMPFAIL,
 348                     "Unable to allocate %zu bytes of memory for recv list locks.",
 349                     sizeof(hio_recv_list_lock[0]) * ncomps);
 350         }
 351         hio_recv_list_cond = malloc(sizeof(hio_recv_list_cond[0]) * ncomps);
 352         if (hio_recv_list_cond == NULL) {
 353                 primary_exitx(EX_TEMPFAIL,
 354                     "Unable to allocate %zu bytes of memory for recv list condition variables.",
 355                     sizeof(hio_recv_list_cond[0]) * ncomps);
 356         }
 357         hio_remote_lock = malloc(sizeof(hio_remote_lock[0]) * ncomps);
 358         if (hio_remote_lock == NULL) {
 359                 primary_exitx(EX_TEMPFAIL,
 360                     "Unable to allocate %zu bytes of memory for remote connections locks.",
 361                     sizeof(hio_remote_lock[0]) * ncomps);
 362         }
 363
 364         /*
 365          * Initialize lists, their locks and theirs condition variables.
 366          */
 367         TAILQ_INIT(&hio_free_list);
 368         mtx_init(&hio_free_list_lock);
 369         cv_init(&hio_free_list_cond);
 370         for (ii = 0; ii < HAST_NCOMPONENTS; ii++) {
 371                 TAILQ_INIT(&hio_send_list[ii]);
 372                 mtx_init(&hio_send_list_lock[ii]);
 373                 cv_init(&hio_send_list_cond[ii]);
 374                 TAILQ_INIT(&hio_recv_list[ii]);
 375                 mtx_init(&hio_recv_list_lock[ii]);
 376                 cv_init(&hio_recv_list_cond[ii]);
 377                 rw_init(&hio_remote_lock[ii]);
 378         }
 379         TAILQ_INIT(&hio_done_list);
 380         mtx_init(&hio_done_list_lock);
 381         cv_init(&hio_done_list_cond);
 382         mtx_init(&metadata_lock);
 383
 384         /*
 385          * Allocate requests pool and initialize requests.
 386          */
 387         for (ii = 0; ii < HAST_HIO_MAX; ii++) {
 388                 hio = malloc(sizeof(*hio));
 389                 if (hio == NULL) {
 390                         primary_exitx(EX_TEMPFAIL,
 391                             "Unable to allocate %zu bytes of memory for hio request.",
 392                             sizeof(*hio));
 393                 }
 394                 hio->hio_countdown = 0;
 395                 hio->hio_errors = malloc(sizeof(hio->hio_errors[0]) * ncomps);
 396                 if (hio->hio_errors == NULL) {
 397                         primary_exitx(EX_TEMPFAIL,
 398                             "Unable allocate %zu bytes of memory for hio errors.",
 399                             sizeof(hio->hio_errors[0]) * ncomps);
 400                 }
 401                 hio->hio_next = malloc(sizeof(hio->hio_next[0]) * ncomps);
 402                 if (hio->hio_next == NULL) {
 403                         primary_exitx(EX_TEMPFAIL,
 404                             "Unable allocate %zu bytes of memory for hio_next field.",
 405                             sizeof(hio->hio_next[0]) * ncomps);
 406                 }
 407                 hio->hio_ggio.gctl_version = G_GATE_VERSION;
 408                 hio->hio_ggio.gctl_data = malloc(MAXPHYS);
 409                 if (hio->hio_ggio.gctl_data == NULL) {
 410                         primary_exitx(EX_TEMPFAIL,
 411                             "Unable to allocate %zu bytes of memory for gctl_data.",
 412                             MAXPHYS);
 413                 }
 414                 hio->hio_ggio.gctl_length = MAXPHYS;
 415                 hio->hio_ggio.gctl_error = 0;
 416                 TAILQ_INSERT_HEAD(&hio_free_list, hio, hio_free_next);
 417         }
 418 }
 419
 420 static void
 421 init_local(struct hast_resource *res)
 422 {
 423         unsigned char *buf;
 424         size_t mapsize;
 425
 426         if (metadata_read(res, true) < 0)
 427                 exit(EX_NOINPUT);
 428         mtx_init(&res->hr_amp_lock);
 429         if (activemap_init(&res->hr_amp, res->hr_datasize, res->hr_extentsize,
 430             res->hr_local_sectorsize, res->hr_keepdirty) < 0) {
 431                 primary_exit(EX_TEMPFAIL, "Unable to create activemap");
 432         }
 433         mtx_init(&range_lock);
 434         cv_init(&range_regular_cond);
 435         if (rangelock_init(&range_regular) < 0)
 436                 primary_exit(EX_TEMPFAIL, "Unable to create regular range lock");
 437         cv_init(&range_sync_cond);
 438         if (rangelock_init(&range_sync) < 0)
 439                 primary_exit(EX_TEMPFAIL, "Unable to create sync range lock");
 440         mapsize = activemap_ondisk_size(res->hr_amp);
 441         buf = calloc(1, mapsize);
 442         if (buf == NULL) {
 443                 primary_exitx(EX_TEMPFAIL,
 444                     "Unable to allocate buffer for activemap.");
 445         }
 446         if (pread(res->hr_localfd, buf, mapsize, METADATA_SIZE) !=
 447             (ssize_t)mapsize) {
 448                 primary_exit(EX_NOINPUT, "Unable to read activemap");
 449         }
 450         activemap_copyin(res->hr_amp, buf, mapsize);
 451         free(buf);
 452         if (res->hr_resuid != 0)
 453                 return;
 454         /*
 455          * We're using provider for the first time, so we have to generate
 456          * resource unique identifier and initialize local and remote counts.
 457          */
 458         arc4random_buf(&res->hr_resuid, sizeof(res->hr_resuid));
 459         res->hr_primary_localcnt = 1;
 460         res->hr_primary_remotecnt = 0;
 461         if (metadata_write(res) < 0)
 462                 exit(EX_NOINPUT);
 463 }
 464
 465 static bool
 466 init_remote(struct hast_resource *res, struct proto_conn **inp,
 467     struct proto_conn **outp)
 468 {
 469         struct proto_conn *in, *out;
 470         struct nv *nvout, *nvin;
 471         const unsigned char *token;
 472         unsigned char *map;
 473         const char *errmsg;
 474         int32_t extentsize;
 475         int64_t datasize;
 476         uint32_t mapsize;
 477         size_t size;
 478
 479         assert((inp == NULL && outp == NULL) || (inp != NULL && outp != NULL));
 480         assert(real_remote(res));
 481
 482         in = out = NULL;
 483         errmsg = NULL;
 484
 485         /* Prepare outgoing connection with remote node. */
 486         if (proto_client(res->hr_remoteaddr, &out) < 0) {
 487                 primary_exit(EX_TEMPFAIL, "Unable to create connection to %s",
 488                     res->hr_remoteaddr);
 489         }
 490         /* Try to connect, but accept failure. */
 491         if (proto_connect(out) < 0) {
 492                 pjdlog_errno(LOG_WARNING, "Unable to connect to %s",
 493                     res->hr_remoteaddr);
 494                 goto close;
 495         }
 496         /* Error in setting timeout is not critical, but why should it fail? */
 497         if (proto_timeout(out, res->hr_timeout) < 0)
 498                 pjdlog_errno(LOG_WARNING, "Unable to set connection timeout");
 499         /*
 500          * First handshake step.
 501          * Setup outgoing connection with remote node.
 502          */
 503         nvout = nv_alloc();
 504         nv_add_string(nvout, res->hr_name, "resource");
 505         if (nv_error(nvout) != 0) {
 506                 pjdlog_common(LOG_WARNING, 0, nv_error(nvout),
 507                     "Unable to allocate header for connection with %s",
 508                     res->hr_remoteaddr);
 509                 nv_free(nvout);
 510                 goto close;
 511         }
 512         if (hast_proto_send(res, out, nvout, NULL, 0) < 0) {
 513                 pjdlog_errno(LOG_WARNING,
 514                     "Unable to send handshake header to %s",
 515                     res->hr_remoteaddr);
 516                 nv_free(nvout);
 517                 goto close;
 518         }
 519         nv_free(nvout);
 520         if (hast_proto_recv_hdr(out, &nvin) < 0) {
 521                 pjdlog_errno(LOG_WARNING,
 522                     "Unable to receive handshake header from %s",
 523                     res->hr_remoteaddr);
 524                 goto close;
 525         }
 526         errmsg = nv_get_string(nvin, "errmsg");
 527         if (errmsg != NULL) {
 528                 pjdlog_warning("%s", errmsg);
 529                 nv_free(nvin);
 530                 goto close;
 531         }
 532         token = nv_get_uint8_array(nvin, &size, "token");
 533         if (token == NULL) {
 534                 pjdlog_warning("Handshake header from %s has no 'token' field.",
 535                     res->hr_remoteaddr);
 536                 nv_free(nvin);
 537                 goto close;
 538         }
 539         if (size != sizeof(res->hr_token)) {
 540                 pjdlog_warning("Handshake header from %s contains 'token' of wrong size (got %zu, expected %zu).",
 541                     res->hr_remoteaddr, size, sizeof(res->hr_token));
 542                 nv_free(nvin);
 543                 goto close;
 544         }
 545         bcopy(token, res->hr_token, sizeof(res->hr_token));
 546         nv_free(nvin);
 547
 548         /*
 549          * Second handshake step.
 550          * Setup incoming connection with remote node.
 551          */
 552         if (proto_client(res->hr_remoteaddr, &in) < 0) {
 553                 pjdlog_errno(LOG_WARNING, "Unable to create connection to %s",
 554                     res->hr_remoteaddr);
 555         }
 556         /* Try to connect, but accept failure. */
 557         if (proto_connect(in) < 0) {
 558                 pjdlog_errno(LOG_WARNING, "Unable to connect to %s",
 559                     res->hr_remoteaddr);
 560                 goto close;
 561         }
 562         /* Error in setting timeout is not critical, but why should it fail? */
 563         if (proto_timeout(in, res->hr_timeout) < 0)
 564                 pjdlog_errno(LOG_WARNING, "Unable to set connection timeout");
 565         nvout = nv_alloc();
 566         nv_add_string(nvout, res->hr_name, "resource");
 567         nv_add_uint8_array(nvout, res->hr_token, sizeof(res->hr_token),
 568             "token");
 569         nv_add_uint64(nvout, res->hr_resuid, "resuid");
 570         nv_add_uint64(nvout, res->hr_primary_localcnt, "localcnt");
 571         nv_add_uint64(nvout, res->hr_primary_remotecnt, "remotecnt");
 572         if (nv_error(nvout) != 0) {
 573                 pjdlog_common(LOG_WARNING, 0, nv_error(nvout),
 574                     "Unable to allocate header for connection with %s",
 575                     res->hr_remoteaddr);
 576                 nv_free(nvout);
 577                 goto close;
 578         }
 579         if (hast_proto_send(res, in, nvout, NULL, 0) < 0) {
 580                 pjdlog_errno(LOG_WARNING,
 581                     "Unable to send handshake header to %s",
 582                     res->hr_remoteaddr);
 583                 nv_free(nvout);
 584                 goto close;
 585         }
 586         nv_free(nvout);
 587         if (hast_proto_recv_hdr(out, &nvin) < 0) {
 588                 pjdlog_errno(LOG_WARNING,
 589                     "Unable to receive handshake header from %s",
 590                     res->hr_remoteaddr);
 591                 goto close;
 592         }
 593         errmsg = nv_get_string(nvin, "errmsg");
 594         if (errmsg != NULL) {
 595                 pjdlog_warning("%s", errmsg);
 596                 nv_free(nvin);
 597                 goto close;
 598         }
 599         datasize = nv_get_int64(nvin, "datasize");
 600         if (datasize != res->hr_datasize) {
 601                 pjdlog_warning("Data size differs between nodes (local=%jd, remote=%jd).",
 602                     (intmax_t)res->hr_datasize, (intmax_t)datasize);
 603                 nv_free(nvin);
 604                 goto close;
 605         }
 606         extentsize = nv_get_int32(nvin, "extentsize");
 607         if (extentsize != res->hr_extentsize) {
 608                 pjdlog_warning("Extent size differs between nodes (local=%zd, remote=%zd).",
 609                     (ssize_t)res->hr_extentsize, (ssize_t)extentsize);
 610                 nv_free(nvin);
 611                 goto close;
 612         }
 613         res->hr_secondary_localcnt = nv_get_uint64(nvin, "localcnt");
 614         res->hr_secondary_remotecnt = nv_get_uint64(nvin, "remotecnt");
 615         res->hr_syncsrc = nv_get_uint8(nvin, "syncsrc");
 616         map = NULL;
 617         mapsize = nv_get_uint32(nvin, "mapsize");
 618         if (mapsize > 0) {
 619                 map = malloc(mapsize);
 620                 if (map == NULL) {
 621                         pjdlog_error("Unable to allocate memory for remote activemap (mapsize=%ju).",
 622                             (uintmax_t)mapsize);
 623                         nv_free(nvin);
 624                         goto close;
 625                 }
 626                 /*
 627                  * Remote node have some dirty extents on its own, lets
 628                  * download its activemap.
 629                  */
 630                 if (hast_proto_recv_data(res, out, nvin, map,
 631                     mapsize) < 0) {
 632                         pjdlog_errno(LOG_ERR,
 633                             "Unable to receive remote activemap");
 634                         nv_free(nvin);
 635                         free(map);
 636                         goto close;
 637                 }
 638                 /*
 639                  * Merge local and remote bitmaps.
 640                  */
 641                 activemap_merge(res->hr_amp, map, mapsize);
 642                 free(map);
 643                 /*
 644                  * Now that we merged bitmaps from both nodes, flush it to the
 645                  * disk before we start to synchronize.
 646                  */
 647                 (void)hast_activemap_flush(res);
 648         }
 649         pjdlog_info("Connected to %s.", res->hr_remoteaddr);
 650         if (inp != NULL && outp != NULL) {
 651                 *inp = in;
 652                 *outp = out;
 653         } else {
 654                 res->hr_remotein = in;
 655                 res->hr_remoteout = out;
 656         }
 657         event_send(res, EVENT_CONNECT);
 658         return (true);
 659 close:
 660         if (errmsg != NULL && strcmp(errmsg, "Split-brain condition!") == 0)
 661                 event_send(res, EVENT_SPLITBRAIN);
 662         proto_close(out);
 663         if (in != NULL)
 664                 proto_close(in);
 665         return (false);
 666 }
 667
 668 static void
 669 sync_start(void)
 670 {
 671
 672         mtx_lock(&sync_lock);
 673         sync_inprogress = true;
 674         mtx_unlock(&sync_lock);
 675         cv_signal(&sync_cond);
 676 }
 677
 678 static void
 679 sync_stop(void)
 680 {
 681
 682         mtx_lock(&sync_lock);
 683         if (sync_inprogress)
 684                 sync_inprogress = false;
 685         mtx_unlock(&sync_lock);
 686 }
 687
 688 static void
 689 init_ggate(struct hast_resource *res)
 690 {
 691         struct g_gate_ctl_create ggiocreate;
 692         struct g_gate_ctl_cancel ggiocancel;
 693
 694         /*
 695          * We communicate with ggate via /dev/ggctl. Open it.
 696          */
 697         res->hr_ggatefd = open("/dev/" G_GATE_CTL_NAME, O_RDWR);
 698         if (res->hr_ggatefd < 0)
 699                 primary_exit(EX_OSFILE, "Unable to open /dev/" G_GATE_CTL_NAME);
 700         /*
 701          * Create provider before trying to connect, as connection failure
 702          * is not critical, but may take some time.
 703          */
 704         bzero(&ggiocreate, sizeof(ggiocreate));
 705         ggiocreate.gctl_version = G_GATE_VERSION;
 706         ggiocreate.gctl_mediasize = res->hr_datasize;
 707         ggiocreate.gctl_sectorsize = res->hr_local_sectorsize;
 708         ggiocreate.gctl_flags = 0;
 709         ggiocreate.gctl_maxcount = G_GATE_MAX_QUEUE_SIZE;
 710         ggiocreate.gctl_timeout = 0;
 711         ggiocreate.gctl_unit = G_GATE_NAME_GIVEN;
 712         snprintf(ggiocreate.gctl_name, sizeof(ggiocreate.gctl_name), "hast/%s",
 713             res->hr_provname);
 714         if (ioctl(res->hr_ggatefd, G_GATE_CMD_CREATE, &ggiocreate) == 0) {
 715                 pjdlog_info("Device hast/%s created.", res->hr_provname);
 716                 res->hr_ggateunit = ggiocreate.gctl_unit;
 717                 return;
 718         }
 719         if (errno != EEXIST) {
 720                 primary_exit(EX_OSERR, "Unable to create hast/%s device",
 721                     res->hr_provname);
 722         }
 723         pjdlog_debug(1,
 724             "Device hast/%s already exists, we will try to take it over.",
 725             res->hr_provname);
 726         /*
 727          * If we received EEXIST, we assume that the process who created the
 728          * provider died and didn't clean up. In that case we will start from
 729          * where he left of.
 730          */
 731         bzero(&ggiocancel, sizeof(ggiocancel));
 732         ggiocancel.gctl_version = G_GATE_VERSION;
 733         ggiocancel.gctl_unit = G_GATE_NAME_GIVEN;
 734         snprintf(ggiocancel.gctl_name, sizeof(ggiocancel.gctl_name), "hast/%s",
 735             res->hr_provname);
 736         if (ioctl(res->hr_ggatefd, G_GATE_CMD_CANCEL, &ggiocancel) == 0) {
 737                 pjdlog_info("Device hast/%s recovered.", res->hr_provname);
 738                 res->hr_ggateunit = ggiocancel.gctl_unit;
 739                 return;
 740         }
 741         primary_exit(EX_OSERR, "Unable to take over hast/%s device",
 742             res->hr_provname);
 743 }
 744
 745 void
 746 hastd_primary(struct hast_resource *res)
 747 {
 748         pthread_t td;
 749         pid_t pid;
 750         int error;
 751
 752         /*
 753          * Create communication channel between parent and child.
 754          */
 755         if (proto_client("socketpair://", &res->hr_ctrl) < 0) {
 756                 KEEP_ERRNO((void)pidfile_remove(pfh));
 757                 pjdlog_exit(EX_OSERR,
 758                     "Unable to create control sockets between parent and child");
 759         }
 760         /*
 761          * Create communication channel between child and parent.
 762          */
 763         if (proto_client("socketpair://", &res->hr_event) < 0) {
 764                 KEEP_ERRNO((void)pidfile_remove(pfh));
 765                 pjdlog_exit(EX_OSERR,
 766                     "Unable to create event sockets between child and parent");
 767         }
 768
 769         pid = fork();
 770         if (pid < 0) {
 771                 KEEP_ERRNO((void)pidfile_remove(pfh));
 772                 pjdlog_exit(EX_TEMPFAIL, "Unable to fork");
 773         }
 774
 775         if (pid > 0) {
 776                 /* This is parent. */
 777                 /* Declare that we are receiver. */
 778                 proto_recv(res->hr_event, NULL, 0);
 779                 res->hr_workerpid = pid;
 780                 return;
 781         }
 782
 783         gres = res;
 784
 785         (void)pidfile_close(pfh);
 786         hook_fini();
 787
 788         setproctitle("%s (primary)", res->hr_name);
 789
 790         /* Declare that we are sender. */
 791         proto_send(res->hr_event, NULL, 0);
 792
 793         init_local(res);
 794         init_ggate(res);
 795         init_environment(res);
 796         /*
 797          * Create the guard thread first, so we can handle signals from the
 798          * very begining.
 799          */
 800         error = pthread_create(&td, NULL, guard_thread, res);
 801         assert(error == 0);
 802         /*
 803          * Create the control thread before sending any event to the parent,
 804          * as we can deadlock when parent sends control request to worker,
 805          * but worker has no control thread started yet, so parent waits.
 806          * In the meantime worker sends an event to the parent, but parent
 807          * is unable to handle the event, because it waits for control
 808          * request response.
 809          */
 810         error = pthread_create(&td, NULL, ctrl_thread, res);
 811         assert(error == 0);
 812         if (real_remote(res) && init_remote(res, NULL, NULL))
 813                 sync_start();
 814         error = pthread_create(&td, NULL, ggate_recv_thread, res);
 815         assert(error == 0);
 816         error = pthread_create(&td, NULL, local_send_thread, res);
 817         assert(error == 0);
 818         error = pthread_create(&td, NULL, remote_send_thread, res);
 819         assert(error == 0);
 820         error = pthread_create(&td, NULL, remote_recv_thread, res);
 821         assert(error == 0);
 822         error = pthread_create(&td, NULL, ggate_send_thread, res);
 823         assert(error == 0);
 824         (void)sync_thread(res);
 825 }
 826
 827 static void
 828 reqlog(int loglevel, int debuglevel, struct g_gate_ctl_io *ggio, const char *fmt, ...)
 829 {
 830         char msg[1024];
 831         va_list ap;
 832         int len;
 833
 834         va_start(ap, fmt);
 835         len = vsnprintf(msg, sizeof(msg), fmt, ap);
 836         va_end(ap);
 837         if ((size_t)len < sizeof(msg)) {
 838                 switch (ggio->gctl_cmd) {
 839                 case BIO_READ:
 840                         (void)snprintf(msg + len, sizeof(msg) - len,
 841                             "READ(%ju, %ju).", (uintmax_t)ggio->gctl_offset,
 842                             (uintmax_t)ggio->gctl_length);
 843                         break;
 844                 case BIO_DELETE:
 845                         (void)snprintf(msg + len, sizeof(msg) - len,
 846                             "DELETE(%ju, %ju).", (uintmax_t)ggio->gctl_offset,
 847                             (uintmax_t)ggio->gctl_length);
 848                         break;
 849                 case BIO_FLUSH:
 850                         (void)snprintf(msg + len, sizeof(msg) - len, "FLUSH.");
 851                         break;
 852                 case BIO_WRITE:
 853                         (void)snprintf(msg + len, sizeof(msg) - len,
 854                             "WRITE(%ju, %ju).", (uintmax_t)ggio->gctl_offset,
 855                             (uintmax_t)ggio->gctl_length);
 856                         break;
 857                 default:
 858                         (void)snprintf(msg + len, sizeof(msg) - len,
 859                             "UNKNOWN(%u).", (unsigned int)ggio->gctl_cmd);
 860                         break;
 861                 }
 862         }
 863         pjdlog_common(loglevel, debuglevel, -1, "%s", msg);
 864 }
 865
 866 static void
 867 remote_close(struct hast_resource *res, int ncomp)
 868 {
 869
 870         rw_wlock(&hio_remote_lock[ncomp]);
 871         /*
 872          * A race is possible between dropping rlock and acquiring wlock -
 873          * another thread can close connection in-between.
 874          */
 875         if (!ISCONNECTED(res, ncomp)) {
 876                 assert(res->hr_remotein == NULL);
 877                 assert(res->hr_remoteout == NULL);
 878                 rw_unlock(&hio_remote_lock[ncomp]);
 879                 return;
 880         }
 881
 882         assert(res->hr_remotein != NULL);
 883         assert(res->hr_remoteout != NULL);
 884
 885         pjdlog_debug(2, "Closing incoming connection to %s.",
 886             res->hr_remoteaddr);
 887         proto_close(res->hr_remotein);
 888         res->hr_remotein = NULL;
 889         pjdlog_debug(2, "Closing outgoing connection to %s.",
 890             res->hr_remoteaddr);
 891         proto_close(res->hr_remoteout);
 892         res->hr_remoteout = NULL;
 893
 894         rw_unlock(&hio_remote_lock[ncomp]);
 895
 896         pjdlog_warning("Disconnected from %s.", res->hr_remoteaddr);
 897
 898         /*
 899          * Stop synchronization if in-progress.
 900          */
 901         sync_stop();
 902
 903         event_send(res, EVENT_DISCONNECT);
 904 }
 905
 906 /*
 907  * Thread receives ggate I/O requests from the kernel and passes them to
 908  * appropriate threads:
 909  * WRITE - always goes to both local_send and remote_send threads
 910  * READ (when the block is up-to-date on local component) -
 911  *      only local_send thread
 912  * READ (when the block isn't up-to-date on local component) -
 913  *      only remote_send thread
 914  * DELETE - always goes to both local_send and remote_send threads
 915  * FLUSH - always goes to both local_send and remote_send threads
 916  */
 917 static void *
 918 ggate_recv_thread(void *arg)
 919 {
 920         struct hast_resource *res = arg;
 921         struct g_gate_ctl_io *ggio;
 922         struct hio *hio;
 923         unsigned int ii, ncomp, ncomps;
 924         int error;
 925
 926         ncomps = HAST_NCOMPONENTS;
 927
 928         for (;;) {
 929                 pjdlog_debug(2, "ggate_recv: Taking free request.");
 930                 QUEUE_TAKE2(hio, free);
 931                 pjdlog_debug(2, "ggate_recv: (%p) Got free request.", hio);
 932                 ggio = &hio->hio_ggio;
 933                 ggio->gctl_unit = res->hr_ggateunit;
 934                 ggio->gctl_length = MAXPHYS;
 935                 ggio->gctl_error = 0;
 936                 pjdlog_debug(2,
 937                     "ggate_recv: (%p) Waiting for request from the kernel.",
 938                     hio);
 939                 if (ioctl(res->hr_ggatefd, G_GATE_CMD_START, ggio) < 0) {
 940                         if (sigexit_received)
 941                                 pthread_exit(NULL);
 942                         primary_exit(EX_OSERR, "G_GATE_CMD_START failed");
 943                 }
 944                 error = ggio->gctl_error;
 945                 switch (error) {
 946                 case 0:
 947                         break;
 948                 case ECANCELED:
 949                         /* Exit gracefully. */
 950                         if (!sigexit_received) {
 951                                 pjdlog_debug(2,
 952                                     "ggate_recv: (%p) Received cancel from the kernel.",
 953                                     hio);
 954                                 pjdlog_info("Received cancel from the kernel, exiting.");
 955                         }
 956                         pthread_exit(NULL);
 957                 case ENOMEM:
 958                         /*
 959                          * Buffer too small? Impossible, we allocate MAXPHYS
 960                          * bytes - request can't be bigger than that.
 961                          */
 962                         /* FALLTHROUGH */
 963                 case ENXIO:
 964                 default:
 965                         primary_exitx(EX_OSERR, "G_GATE_CMD_START failed: %s.",
 966                             strerror(error));
 967                 }
 968                 for (ii = 0; ii < ncomps; ii++)
 969                         hio->hio_errors[ii] = EINVAL;
 970                 reqlog(LOG_DEBUG, 2, ggio,
 971                     "ggate_recv: (%p) Request received from the kernel: ",
 972                     hio);
 973                 /*
 974                  * Inform all components about new write request.
 975                  * For read request prefer local component unless the given
 976                  * range is out-of-date, then use remote component.
 977                  */
 978                 switch (ggio->gctl_cmd) {
 979                 case BIO_READ:
 980                         pjdlog_debug(2,
 981                             "ggate_recv: (%p) Moving request to the send queue.",
 982                             hio);
 983                         refcount_init(&hio->hio_countdown, 1);
 984                         mtx_lock(&metadata_lock);
 985                         if (res->hr_syncsrc == HAST_SYNCSRC_UNDEF ||
 986                             res->hr_syncsrc == HAST_SYNCSRC_PRIMARY) {
 987                                 /*
 988                                  * This range is up-to-date on local component,
 989                                  * so handle request locally.
 990                                  */
 991                                  /* Local component is 0 for now. */
 992                                 ncomp = 0;
 993                         } else /* if (res->hr_syncsrc ==
 994                             HAST_SYNCSRC_SECONDARY) */ {
 995                                 assert(res->hr_syncsrc ==
 996                                     HAST_SYNCSRC_SECONDARY);
 997                                 /*
 998                                  * This range is out-of-date on local component,
 999                                  * so send request to the remote node.
1000                                  */
1001                                  /* Remote component is 1 for now. */
1002                                 ncomp = 1;
1003                         }
1004                         mtx_unlock(&metadata_lock);
1005                         QUEUE_INSERT1(hio, send, ncomp);
1006                         break;
1007                 case BIO_WRITE:
1008                         for (;;) {
1009                                 mtx_lock(&range_lock);
1010                                 if (rangelock_islocked(range_sync,
1011                                     ggio->gctl_offset, ggio->gctl_length)) {
1012                                         pjdlog_debug(2,
1013                                             "regular: Range offset=%jd length=%zu locked.",
1014                                             (intmax_t)ggio->gctl_offset,
1015                                             (size_t)ggio->gctl_length);
1016                                         range_regular_wait = true;
1017                                         cv_wait(&range_regular_cond, &range_lock);
1018                                         range_regular_wait = false;
1019                                         mtx_unlock(&range_lock);
1020                                         continue;
1021                                 }
1022                                 if (rangelock_add(range_regular,
1023                                     ggio->gctl_offset, ggio->gctl_length) < 0) {
1024                                         mtx_unlock(&range_lock);
1025                                         pjdlog_debug(2,
1026                                             "regular: Range offset=%jd length=%zu is already locked, waiting.",
1027                                             (intmax_t)ggio->gctl_offset,
1028                                             (size_t)ggio->gctl_length);
1029                                         sleep(1);
1030                                         continue;
1031                                 }
1032                                 mtx_unlock(&range_lock);
1033                                 break;
1034                         }
1035                         mtx_lock(&res->hr_amp_lock);
1036                         if (activemap_write_start(res->hr_amp,
1037                             ggio->gctl_offset, ggio->gctl_length)) {
1038                                 (void)hast_activemap_flush(res);
1039                         }
1040                         mtx_unlock(&res->hr_amp_lock);
1041                         /* FALLTHROUGH */
1042                 case BIO_DELETE:
1043                 case BIO_FLUSH:
1044                         pjdlog_debug(2,
1045                             "ggate_recv: (%p) Moving request to the send queues.",
1046                             hio);
1047                         refcount_init(&hio->hio_countdown, ncomps);
1048                         for (ii = 0; ii < ncomps; ii++)
1049                                 QUEUE_INSERT1(hio, send, ii);
1050                         break;
1051                 }
1052         }
1053         /* NOTREACHED */
1054         return (NULL);
1055 }
1056
1057 /*
1058  * Thread reads from or writes to local component.
1059  * If local read fails, it redirects it to remote_send thread.
1060  */
1061 static void *
1062 local_send_thread(void *arg)
1063 {
1064         struct hast_resource *res = arg;
1065         struct g_gate_ctl_io *ggio;
1066         struct hio *hio;
1067         unsigned int ncomp, rncomp;
1068         ssize_t ret;
1069
1070         /* Local component is 0 for now. */
1071         ncomp = 0;
1072         /* Remote component is 1 for now. */
1073         rncomp = 1;
1074
1075         for (;;) {
1076                 pjdlog_debug(2, "local_send: Taking request.");
1077                 QUEUE_TAKE1(hio, send, ncomp);
1078                 pjdlog_debug(2, "local_send: (%p) Got request.", hio);
1079                 ggio = &hio->hio_ggio;
1080                 switch (ggio->gctl_cmd) {
1081                 case BIO_READ:
1082                         ret = pread(res->hr_localfd, ggio->gctl_data,
1083                             ggio->gctl_length,
1084                             ggio->gctl_offset + res->hr_localoff);
1085                         if (ret == ggio->gctl_length)
1086                                 hio->hio_errors[ncomp] = 0;
1087                         else {
1088                                 /*
1089                                  * If READ failed, try to read from remote node.
1090                                  */
1091                                 QUEUE_INSERT1(hio, send, rncomp);
1092                                 continue;
1093                         }
1094                         break;
1095                 case BIO_WRITE:
1096                         ret = pwrite(res->hr_localfd, ggio->gctl_data,
1097                             ggio->gctl_length,
1098                             ggio->gctl_offset + res->hr_localoff);
1099                         if (ret < 0)
1100                                 hio->hio_errors[ncomp] = errno;
1101                         else if (ret != ggio->gctl_length)
1102                                 hio->hio_errors[ncomp] = EIO;
1103                         else
1104                                 hio->hio_errors[ncomp] = 0;
1105                         break;
1106                 case BIO_DELETE:
1107                         ret = g_delete(res->hr_localfd,
1108                             ggio->gctl_offset + res->hr_localoff,
1109                             ggio->gctl_length);
1110                         if (ret < 0)
1111                                 hio->hio_errors[ncomp] = errno;
1112                         else
1113                                 hio->hio_errors[ncomp] = 0;
1114                         break;
1115                 case BIO_FLUSH:
1116                         ret = g_flush(res->hr_localfd);
1117                         if (ret < 0)
1118                                 hio->hio_errors[ncomp] = errno;
1119                         else
1120                                 hio->hio_errors[ncomp] = 0;
1121                         break;
1122                 }
1123                 if (refcount_release(&hio->hio_countdown)) {
1124                         if (ISSYNCREQ(hio)) {
1125                                 mtx_lock(&sync_lock);
1126                                 SYNCREQDONE(hio);
1127                                 mtx_unlock(&sync_lock);
1128                                 cv_signal(&sync_cond);
1129                         } else {
1130                                 pjdlog_debug(2,
1131                                     "local_send: (%p) Moving request to the done queue.",
1132                                     hio);
1133                                 QUEUE_INSERT2(hio, done);
1134                         }
1135                 }
1136         }
1137         /* NOTREACHED */
1138         return (NULL);
1139 }
1140
1141 /*
1142  * Thread sends request to secondary node.
1143  */
1144 static void *
1145 remote_send_thread(void *arg)
1146 {
1147         struct hast_resource *res = arg;
1148         struct g_gate_ctl_io *ggio;
1149         struct hio *hio;
1150         struct nv *nv;
1151         unsigned int ncomp;
1152         bool wakeup;
1153         uint64_t offset, length;
1154         uint8_t cmd;
1155         void *data;
1156
1157         /* Remote component is 1 for now. */
1158         ncomp = 1;
1159
1160         for (;;) {
1161                 pjdlog_debug(2, "remote_send: Taking request.");
1162                 QUEUE_TAKE1(hio, send, ncomp);
1163                 pjdlog_debug(2, "remote_send: (%p) Got request.", hio);
1164                 ggio = &hio->hio_ggio;
1165                 switch (ggio->gctl_cmd) {
1166                 case BIO_READ:
1167                         cmd = HIO_READ;
1168                         data = NULL;
1169                         offset = ggio->gctl_offset;
1170                         length = ggio->gctl_length;
1171                         break;
1172                 case BIO_WRITE:
1173                         cmd = HIO_WRITE;
1174                         data = ggio->gctl_data;
1175                         offset = ggio->gctl_offset;
1176                         length = ggio->gctl_length;
1177                         break;
1178                 case BIO_DELETE:
1179                         cmd = HIO_DELETE;
1180                         data = NULL;
1181                         offset = ggio->gctl_offset;
1182                         length = ggio->gctl_length;
1183                         break;
1184                 case BIO_FLUSH:
1185                         cmd = HIO_FLUSH;
1186                         data = NULL;
1187                         offset = 0;
1188                         length = 0;
1189                         break;
1190                 default:
1191                         assert(!"invalid condition");
1192                         abort();
1193                 }
1194                 nv = nv_alloc();
1195                 nv_add_uint8(nv, cmd, "cmd");
1196                 nv_add_uint64(nv, (uint64_t)ggio->gctl_seq, "seq");
1197                 nv_add_uint64(nv, offset, "offset");
1198                 nv_add_uint64(nv, length, "length");
1199                 if (nv_error(nv) != 0) {
1200                         hio->hio_errors[ncomp] = nv_error(nv);
1201                         pjdlog_debug(2,
1202                             "remote_send: (%p) Unable to prepare header to send.",
1203                             hio);
1204                         reqlog(LOG_ERR, 0, ggio,
1205                             "Unable to prepare header to send (%s): ",
1206                             strerror(nv_error(nv)));
1207                         /* Move failed request immediately to the done queue. */
1208                         goto done_queue;
1209                 }
1210                 pjdlog_debug(2,
1211                     "remote_send: (%p) Moving request to the recv queue.",
1212                     hio);
1213                 /*
1214                  * Protect connection from disappearing.
1215                  */
1216                 rw_rlock(&hio_remote_lock[ncomp]);
1217                 if (!ISCONNECTED(res, ncomp)) {
1218                         rw_unlock(&hio_remote_lock[ncomp]);
1219                         hio->hio_errors[ncomp] = ENOTCONN;
1220                         goto done_queue;
1221                 }
1222                 /*
1223                  * Move the request to recv queue before sending it, because
1224                  * in different order we can get reply before we move request
1225                  * to recv queue.
1226                  */
1227                 mtx_lock(&hio_recv_list_lock[ncomp]);
1228                 wakeup = TAILQ_EMPTY(&hio_recv_list[ncomp]);
1229                 TAILQ_INSERT_TAIL(&hio_recv_list[ncomp], hio, hio_next[ncomp]);
1230                 mtx_unlock(&hio_recv_list_lock[ncomp]);
1231                 if (hast_proto_send(res, res->hr_remoteout, nv, data,
1232                     data != NULL ? length : 0) < 0) {
1233                         hio->hio_errors[ncomp] = errno;
1234                         rw_unlock(&hio_remote_lock[ncomp]);
1235                         pjdlog_debug(2,
1236                             "remote_send: (%p) Unable to send request.", hio);
1237                         reqlog(LOG_ERR, 0, ggio,
1238                             "Unable to send request (%s): ",
1239                             strerror(hio->hio_errors[ncomp]));
1240                         remote_close(res, ncomp);
1241                         /*
1242                          * Take request back from the receive queue and move
1243                          * it immediately to the done queue.
1244                          */
1245                         mtx_lock(&hio_recv_list_lock[ncomp]);
1246                         TAILQ_REMOVE(&hio_recv_list[ncomp], hio, hio_next[ncomp]);
1247                         mtx_unlock(&hio_recv_list_lock[ncomp]);
1248                         goto done_queue;
1249                 }
1250                 rw_unlock(&hio_remote_lock[ncomp]);
1251                 nv_free(nv);
1252                 if (wakeup)
1253                         cv_signal(&hio_recv_list_cond[ncomp]);
1254                 continue;
1255 done_queue:
1256                 nv_free(nv);
1257                 if (ISSYNCREQ(hio)) {
1258                         if (!refcount_release(&hio->hio_countdown))
1259                                 continue;
1260                         mtx_lock(&sync_lock);
1261                         SYNCREQDONE(hio);
1262                         mtx_unlock(&sync_lock);
1263                         cv_signal(&sync_cond);
1264                         continue;
1265                 }
1266                 if (ggio->gctl_cmd == BIO_WRITE) {
1267                         mtx_lock(&res->hr_amp_lock);
1268                         if (activemap_need_sync(res->hr_amp, ggio->gctl_offset,
1269                             ggio->gctl_length)) {
1270                                 (void)hast_activemap_flush(res);
1271                         }
1272                         mtx_unlock(&res->hr_amp_lock);
1273                 }
1274                 if (!refcount_release(&hio->hio_countdown))
1275                         continue;
1276                 pjdlog_debug(2,
1277                     "remote_send: (%p) Moving request to the done queue.",
1278                     hio);
1279                 QUEUE_INSERT2(hio, done);
1280         }
1281         /* NOTREACHED */
1282         return (NULL);
1283 }
1284
1285 /*
1286  * Thread receives answer from secondary node and passes it to ggate_send
1287  * thread.
1288  */
1289 static void *
1290 remote_recv_thread(void *arg)
1291 {
1292         struct hast_resource *res = arg;
1293         struct g_gate_ctl_io *ggio;
1294         struct hio *hio;
1295         struct nv *nv;
1296         unsigned int ncomp;
1297         uint64_t seq;
1298         int error;
1299
1300         /* Remote component is 1 for now. */
1301         ncomp = 1;
1302
1303         for (;;) {
1304                 /* Wait until there is anything to receive. */
1305                 mtx_lock(&hio_recv_list_lock[ncomp]);
1306                 while (TAILQ_EMPTY(&hio_recv_list[ncomp])) {
1307                         pjdlog_debug(2, "remote_recv: No requests, waiting.");
1308                         cv_wait(&hio_recv_list_cond[ncomp],
1309                             &hio_recv_list_lock[ncomp]);
1310                 }
1311                 mtx_unlock(&hio_recv_list_lock[ncomp]);
1312                 rw_rlock(&hio_remote_lock[ncomp]);
1313                 if (!ISCONNECTED(res, ncomp)) {
1314                         rw_unlock(&hio_remote_lock[ncomp]);
1315                         /*
1316                          * Connection is dead, so move all pending requests to
1317                          * the done queue (one-by-one).
1318                          */
1319                         mtx_lock(&hio_recv_list_lock[ncomp]);
1320                         hio = TAILQ_FIRST(&hio_recv_list[ncomp]);
1321                         assert(hio != NULL);
1322                         TAILQ_REMOVE(&hio_recv_list[ncomp], hio,
1323                             hio_next[ncomp]);
1324                         mtx_unlock(&hio_recv_list_lock[ncomp]);
1325                         goto done_queue;
1326                 }
1327                 if (hast_proto_recv_hdr(res->hr_remotein, &nv) < 0) {
1328                         pjdlog_errno(LOG_ERR,
1329                             "Unable to receive reply header");
1330                         rw_unlock(&hio_remote_lock[ncomp]);
1331                         remote_close(res, ncomp);
1332                         continue;
1333                 }
1334                 rw_unlock(&hio_remote_lock[ncomp]);
1335                 seq = nv_get_uint64(nv, "seq");
1336                 if (seq == 0) {
1337                         pjdlog_error("Header contains no 'seq' field.");
1338                         nv_free(nv);
1339                         continue;
1340                 }
1341                 mtx_lock(&hio_recv_list_lock[ncomp]);
1342                 TAILQ_FOREACH(hio, &hio_recv_list[ncomp], hio_next[ncomp]) {
1343                         if (hio->hio_ggio.gctl_seq == seq) {
1344                                 TAILQ_REMOVE(&hio_recv_list[ncomp], hio,
1345                                     hio_next[ncomp]);
1346                                 break;
1347                         }
1348                 }
1349                 mtx_unlock(&hio_recv_list_lock[ncomp]);
1350                 if (hio == NULL) {
1351                         pjdlog_error("Found no request matching received 'seq' field (%ju).",
1352                             (uintmax_t)seq);
1353                         nv_free(nv);
1354                         continue;
1355                 }
1356                 error = nv_get_int16(nv, "error");
1357                 if (error != 0) {
1358                         /* Request failed on remote side. */
1359                         hio->hio_errors[ncomp] = 0;
1360                         nv_free(nv);
1361                         goto done_queue;
1362                 }
1363                 ggio = &hio->hio_ggio;
1364                 switch (ggio->gctl_cmd) {
1365                 case BIO_READ:
1366                         rw_rlock(&hio_remote_lock[ncomp]);
1367                         if (!ISCONNECTED(res, ncomp)) {
1368                                 rw_unlock(&hio_remote_lock[ncomp]);
1369                                 nv_free(nv);
1370                                 goto done_queue;
1371                         }
1372                         if (hast_proto_recv_data(res, res->hr_remotein, nv,
1373                             ggio->gctl_data, ggio->gctl_length) < 0) {
1374                                 hio->hio_errors[ncomp] = errno;
1375                                 pjdlog_errno(LOG_ERR,
1376                                     "Unable to receive reply data");
1377                                 rw_unlock(&hio_remote_lock[ncomp]);
1378                                 nv_free(nv);
1379                                 remote_close(res, ncomp);
1380                                 goto done_queue;
1381                         }
1382                         rw_unlock(&hio_remote_lock[ncomp]);
1383                         break;
1384                 case BIO_WRITE:
1385                 case BIO_DELETE:
1386                 case BIO_FLUSH:
1387                         break;
1388                 default:
1389                         assert(!"invalid condition");
1390                         abort();
1391                 }
1392                 hio->hio_errors[ncomp] = 0;
1393                 nv_free(nv);
1394 done_queue:
1395                 if (refcount_release(&hio->hio_countdown)) {
1396                         if (ISSYNCREQ(hio)) {
1397                                 mtx_lock(&sync_lock);
1398                                 SYNCREQDONE(hio);
1399                                 mtx_unlock(&sync_lock);
1400                                 cv_signal(&sync_cond);
1401                         } else {
1402                                 pjdlog_debug(2,
1403                                     "remote_recv: (%p) Moving request to the done queue.",
1404                                     hio);
1405                                 QUEUE_INSERT2(hio, done);
1406                         }
1407                 }
1408         }
1409         /* NOTREACHED */
1410         return (NULL);
1411 }
1412
1413 /*
1414  * Thread sends answer to the kernel.
1415  */
1416 static void *
1417 ggate_send_thread(void *arg)
1418 {
1419         struct hast_resource *res = arg;
1420         struct g_gate_ctl_io *ggio;
1421         struct hio *hio;
1422         unsigned int ii, ncomp, ncomps;
1423
1424         ncomps = HAST_NCOMPONENTS;
1425
1426         for (;;) {
1427                 pjdlog_debug(2, "ggate_send: Taking request.");
1428                 QUEUE_TAKE2(hio, done);
1429                 pjdlog_debug(2, "ggate_send: (%p) Got request.", hio);
1430                 ggio = &hio->hio_ggio;
1431                 for (ii = 0; ii < ncomps; ii++) {
1432                         if (hio->hio_errors[ii] == 0) {
1433                                 /*
1434                                  * One successful request is enough to declare
1435                                  * success.
1436                                  */
1437                                 ggio->gctl_error = 0;
1438                                 break;
1439                         }
1440                 }
1441                 if (ii == ncomps) {
1442                         /*
1443                          * None of the requests were successful.
1444                          * Use first error.
1445                          */
1446                         ggio->gctl_error = hio->hio_errors[0];
1447                 }
1448                 if (ggio->gctl_error == 0 && ggio->gctl_cmd == BIO_WRITE) {
1449                         mtx_lock(&res->hr_amp_lock);
1450                         activemap_write_complete(res->hr_amp,
1451                             ggio->gctl_offset, ggio->gctl_length);
1452                         mtx_unlock(&res->hr_amp_lock);
1453                 }
1454                 if (ggio->gctl_cmd == BIO_WRITE) {
1455                         /*
1456                          * Unlock range we locked.
1457                          */
1458                         mtx_lock(&range_lock);
1459                         rangelock_del(range_regular, ggio->gctl_offset,
1460                             ggio->gctl_length);
1461                         if (range_sync_wait)
1462                                 cv_signal(&range_sync_cond);
1463                         mtx_unlock(&range_lock);
1464                         /*
1465                          * Bump local count if this is first write after
1466                          * connection failure with remote node.
1467                          */
1468                         ncomp = 1;
1469                         rw_rlock(&hio_remote_lock[ncomp]);
1470                         if (!ISCONNECTED(res, ncomp)) {
1471                                 mtx_lock(&metadata_lock);
1472                                 if (res->hr_primary_localcnt ==
1473                                     res->hr_secondary_remotecnt) {
1474                                         res->hr_primary_localcnt++;
1475                                         pjdlog_debug(1,
1476                                             "Increasing localcnt to %ju.",
1477                                             (uintmax_t)res->hr_primary_localcnt);
1478                                         (void)metadata_write(res);
1479                                 }
1480                                 mtx_unlock(&metadata_lock);
1481                         }
1482                         rw_unlock(&hio_remote_lock[ncomp]);
1483                 }
1484                 if (ioctl(res->hr_ggatefd, G_GATE_CMD_DONE, ggio) < 0)
1485                         primary_exit(EX_OSERR, "G_GATE_CMD_DONE failed");
1486                 pjdlog_debug(2,
1487                     "ggate_send: (%p) Moving request to the free queue.", hio);
1488                 QUEUE_INSERT2(hio, free);
1489         }
1490         /* NOTREACHED */
1491         return (NULL);
1492 }
1493
1494 /*
1495  * Thread synchronize local and remote components.
1496  */
1497 static void *
1498 sync_thread(void *arg __unused)
1499 {
1500         struct hast_resource *res = arg;
1501         struct hio *hio;
1502         struct g_gate_ctl_io *ggio;
1503         unsigned int ii, ncomp, ncomps;
1504         off_t offset, length, synced;
1505         bool dorewind;
1506         int syncext;
1507
1508         ncomps = HAST_NCOMPONENTS;
1509         dorewind = true;
1510         synced = 0;
1511         offset = -1;
1512
1513         for (;;) {
1514                 mtx_lock(&sync_lock);
1515                 if (offset >= 0 && !sync_inprogress) {
1516                         pjdlog_info("Synchronization interrupted. "
1517                             "%jd bytes synchronized so far.",
1518                             (intmax_t)synced);
1519                         event_send(res, EVENT_SYNCINTR);
1520                 }
1521                 while (!sync_inprogress) {
1522                         dorewind = true;
1523                         synced = 0;
1524                         cv_wait(&sync_cond, &sync_lock);
1525                 }
1526                 mtx_unlock(&sync_lock);
1527                 /*
1528                  * Obtain offset at which we should synchronize.
1529                  * Rewind synchronization if needed.
1530                  */
1531                 mtx_lock(&res->hr_amp_lock);
1532                 if (dorewind)
1533                         activemap_sync_rewind(res->hr_amp);
1534                 offset = activemap_sync_offset(res->hr_amp, &length, &syncext);
1535                 if (syncext != -1) {
1536                         /*
1537                          * We synchronized entire syncext extent, we can mark
1538                          * it as clean now.
1539                          */
1540                         if (activemap_extent_complete(res->hr_amp, syncext))
1541                                 (void)hast_activemap_flush(res);
1542                 }
1543                 mtx_unlock(&res->hr_amp_lock);
1544                 if (dorewind) {
1545                         dorewind = false;
1546                         if (offset < 0)
1547                                 pjdlog_info("Nodes are in sync.");
1548                         else {
1549                                 pjdlog_info("Synchronization started. %ju bytes to go.",
1550                                     (uintmax_t)(res->hr_extentsize *
1551                                     activemap_ndirty(res->hr_amp)));
1552                                 event_send(res, EVENT_SYNCSTART);
1553                         }
1554                 }
1555                 if (offset < 0) {
1556                         sync_stop();
1557                         pjdlog_debug(1, "Nothing to synchronize.");
1558                         /*
1559                          * Synchronization complete, make both localcnt and
1560                          * remotecnt equal.
1561                          */
1562                         ncomp = 1;
1563                         rw_rlock(&hio_remote_lock[ncomp]);
1564                         if (ISCONNECTED(res, ncomp)) {
1565                                 if (synced > 0) {
1566                                         pjdlog_info("Synchronization complete. "
1567                                             "%jd bytes synchronized.",
1568                                             (intmax_t)synced);
1569                                         event_send(res, EVENT_SYNCDONE);
1570                                 }
1571                                 mtx_lock(&metadata_lock);
1572                                 res->hr_syncsrc = HAST_SYNCSRC_UNDEF;
1573                                 res->hr_primary_localcnt =
1574                                     res->hr_secondary_localcnt;
1575                                 res->hr_primary_remotecnt =
1576                                     res->hr_secondary_remotecnt;
1577                                 pjdlog_debug(1,
1578                                     "Setting localcnt to %ju and remotecnt to %ju.",
1579                                     (uintmax_t)res->hr_primary_localcnt,
1580                                     (uintmax_t)res->hr_secondary_localcnt);
1581                                 (void)metadata_write(res);
1582                                 mtx_unlock(&metadata_lock);
1583                         }
1584                         rw_unlock(&hio_remote_lock[ncomp]);
1585                         continue;
1586                 }
1587                 pjdlog_debug(2, "sync: Taking free request.");
1588                 QUEUE_TAKE2(hio, free);
1589                 pjdlog_debug(2, "sync: (%p) Got free request.", hio);
1590                 /*
1591                  * Lock the range we are going to synchronize. We don't want
1592                  * race where someone writes between our read and write.
1593                  */
1594                 for (;;) {
1595                         mtx_lock(&range_lock);
1596                         if (rangelock_islocked(range_regular, offset, length)) {
1597                                 pjdlog_debug(2,
1598                                     "sync: Range offset=%jd length=%jd locked.",
1599                                     (intmax_t)offset, (intmax_t)length);
1600                                 range_sync_wait = true;
1601                                 cv_wait(&range_sync_cond, &range_lock);
1602                                 range_sync_wait = false;
1603                                 mtx_unlock(&range_lock);
1604                                 continue;
1605                         }
1606                         if (rangelock_add(range_sync, offset, length) < 0) {
1607                                 mtx_unlock(&range_lock);
1608                                 pjdlog_debug(2,
1609                                     "sync: Range offset=%jd length=%jd is already locked, waiting.",
1610                                     (intmax_t)offset, (intmax_t)length);
1611                                 sleep(1);
1612                                 continue;
1613                         }
1614                         mtx_unlock(&range_lock);
1615                         break;
1616                 }
1617                 /*
1618                  * First read the data from synchronization source.
1619                  */
1620                 SYNCREQ(hio);
1621                 ggio = &hio->hio_ggio;
1622                 ggio->gctl_cmd = BIO_READ;
1623                 ggio->gctl_offset = offset;
1624                 ggio->gctl_length = length;
1625                 ggio->gctl_error = 0;
1626                 for (ii = 0; ii < ncomps; ii++)
1627                         hio->hio_errors[ii] = EINVAL;
1628                 reqlog(LOG_DEBUG, 2, ggio, "sync: (%p) Sending sync request: ",
1629                     hio);
1630                 pjdlog_debug(2, "sync: (%p) Moving request to the send queue.",
1631                     hio);
1632                 mtx_lock(&metadata_lock);
1633                 if (res->hr_syncsrc == HAST_SYNCSRC_PRIMARY) {
1634                         /*
1635                          * This range is up-to-date on local component,
1636                          * so handle request locally.
1637                          */
1638                          /* Local component is 0 for now. */
1639                         ncomp = 0;
1640                 } else /* if (res->hr_syncsrc == HAST_SYNCSRC_SECONDARY) */ {
1641                         assert(res->hr_syncsrc == HAST_SYNCSRC_SECONDARY);
1642                         /*
1643                          * This range is out-of-date on local component,
1644                          * so send request to the remote node.
1645                          */
1646                          /* Remote component is 1 for now. */
1647                         ncomp = 1;
1648                 }
1649                 mtx_unlock(&metadata_lock);
1650                 refcount_init(&hio->hio_countdown, 1);
1651                 QUEUE_INSERT1(hio, send, ncomp);
1652
1653                 /*
1654                  * Let's wait for READ to finish.
1655                  */
1656                 mtx_lock(&sync_lock);
1657                 while (!ISSYNCREQDONE(hio))
1658                         cv_wait(&sync_cond, &sync_lock);
1659                 mtx_unlock(&sync_lock);
1660
1661                 if (hio->hio_errors[ncomp] != 0) {
1662                         pjdlog_error("Unable to read synchronization data: %s.",
1663                             strerror(hio->hio_errors[ncomp]));
1664                         goto free_queue;
1665                 }
1666
1667                 /*
1668                  * We read the data from synchronization source, now write it
1669                  * to synchronization target.
1670                  */
1671                 SYNCREQ(hio);
1672                 ggio->gctl_cmd = BIO_WRITE;
1673                 for (ii = 0; ii < ncomps; ii++)
1674                         hio->hio_errors[ii] = EINVAL;
1675                 reqlog(LOG_DEBUG, 2, ggio, "sync: (%p) Sending sync request: ",
1676                     hio);
1677                 pjdlog_debug(2, "sync: (%p) Moving request to the send queue.",
1678                     hio);
1679                 mtx_lock(&metadata_lock);
1680                 if (res->hr_syncsrc == HAST_SYNCSRC_PRIMARY) {
1681                         /*
1682                          * This range is up-to-date on local component,
1683                          * so we update remote component.
1684                          */
1685                          /* Remote component is 1 for now. */
1686                         ncomp = 1;
1687                 } else /* if (res->hr_syncsrc == HAST_SYNCSRC_SECONDARY) */ {
1688                         assert(res->hr_syncsrc == HAST_SYNCSRC_SECONDARY);
1689                         /*
1690                          * This range is out-of-date on local component,
1691                          * so we update it.
1692                          */
1693                          /* Local component is 0 for now. */
1694                         ncomp = 0;
1695                 }
1696                 mtx_unlock(&metadata_lock);
1697
1698                 pjdlog_debug(2, "sync: (%p) Moving request to the send queues.",
1699                     hio);
1700                 refcount_init(&hio->hio_countdown, 1);
1701                 QUEUE_INSERT1(hio, send, ncomp);
1702
1703                 /*
1704                  * Let's wait for WRITE to finish.
1705                  */
1706                 mtx_lock(&sync_lock);
1707                 while (!ISSYNCREQDONE(hio))
1708                         cv_wait(&sync_cond, &sync_lock);
1709                 mtx_unlock(&sync_lock);
1710
1711                 if (hio->hio_errors[ncomp] != 0) {
1712                         pjdlog_error("Unable to write synchronization data: %s.",
1713                             strerror(hio->hio_errors[ncomp]));
1714                         goto free_queue;
1715                 }
1716
1717                 synced += length;
1718 free_queue:
1719                 mtx_lock(&range_lock);
1720                 rangelock_del(range_sync, offset, length);
1721                 if (range_regular_wait)
1722                         cv_signal(&range_regular_cond);
1723                 mtx_unlock(&range_lock);
1724                 pjdlog_debug(2, "sync: (%p) Moving request to the free queue.",
1725                     hio);
1726                 QUEUE_INSERT2(hio, free);
1727         }
1728         /* NOTREACHED */
1729         return (NULL);
1730 }
1731
1732 static void
1733 config_reload(void)
1734 {
1735         struct hastd_config *newcfg;
1736         struct hast_resource *res;
1737         unsigned int ii, ncomps;
1738         int modified;
1739
1740         pjdlog_info("Reloading configuration...");
1741
1742         ncomps = HAST_NCOMPONENTS;
1743
1744         newcfg = yy_config_parse(cfgpath, false);
1745         if (newcfg == NULL)
1746                 goto failed;
1747
1748         TAILQ_FOREACH(res, &newcfg->hc_resources, hr_next) {
1749                 if (strcmp(res->hr_name, gres->hr_name) == 0)
1750                         break;
1751         }
1752         /*
1753          * If resource was removed from the configuration file, resource
1754          * name, provider name or path to local component was modified we
1755          * shouldn't be here. This means that someone modified configuration
1756          * file and send SIGHUP to us instead of main hastd process.
1757          * Log advice and ignore the signal.
1758          */
1759         if (res == NULL || strcmp(gres->hr_name, res->hr_name) != 0 ||
1760             strcmp(gres->hr_provname, res->hr_provname) != 0 ||
1761             strcmp(gres->hr_localpath, res->hr_localpath) != 0) {
1762                 pjdlog_warning("To reload configuration send SIGHUP to the main hastd process (pid %u).",
1763                     (unsigned int)getppid());
1764                 goto failed;
1765         }
1766
1767 #define MODIFIED_REMOTEADDR     0x1
1768 #define MODIFIED_REPLICATION    0x2
1769 #define MODIFIED_TIMEOUT        0x4
1770 #define MODIFIED_EXEC           0x8
1771         modified = 0;
1772         if (strcmp(gres->hr_remoteaddr, res->hr_remoteaddr) != 0) {
1773                 /*
1774                  * Don't copy res->hr_remoteaddr to gres just yet.
1775                  * We want remote_close() to log disconnect from the old
1776                  * addresses, not from the new ones.
1777                  */
1778                 modified |= MODIFIED_REMOTEADDR;
1779         }
1780         if (gres->hr_replication != res->hr_replication) {
1781                 gres->hr_replication = res->hr_replication;
1782                 modified |= MODIFIED_REPLICATION;
1783         }
1784         if (gres->hr_timeout != res->hr_timeout) {
1785                 gres->hr_timeout = res->hr_timeout;
1786                 modified |= MODIFIED_TIMEOUT;
1787         }
1788         if (strcmp(gres->hr_exec, res->hr_exec) != 0) {
1789                 strlcpy(gres->hr_exec, res->hr_exec, sizeof(gres->hr_exec));
1790                 modified |= MODIFIED_EXEC;
1791         }
1792         /*
1793          * If only timeout was modified we only need to change it without
1794          * reconnecting.
1795          */
1796         if (modified == MODIFIED_TIMEOUT) {
1797                 for (ii = 0; ii < ncomps; ii++) {
1798                         if (!ISREMOTE(ii))
1799                                 continue;
1800                         rw_rlock(&hio_remote_lock[ii]);
1801                         if (!ISCONNECTED(gres, ii)) {
1802                                 rw_unlock(&hio_remote_lock[ii]);
1803                                 continue;
1804                         }
1805                         rw_unlock(&hio_remote_lock[ii]);
1806                         if (proto_timeout(gres->hr_remotein,
1807                             gres->hr_timeout) < 0) {
1808                                 pjdlog_errno(LOG_WARNING,
1809                                     "Unable to set connection timeout");
1810                         }
1811                         if (proto_timeout(gres->hr_remoteout,
1812                             gres->hr_timeout) < 0) {
1813                                 pjdlog_errno(LOG_WARNING,
1814                                     "Unable to set connection timeout");
1815                         }
1816                 }
1817         } else if ((modified &
1818             (MODIFIED_REMOTEADDR | MODIFIED_REPLICATION)) != 0) {
1819                 for (ii = 0; ii < ncomps; ii++) {
1820                         if (!ISREMOTE(ii))
1821                                 continue;
1822                         remote_close(gres, ii);
1823                 }
1824                 if (modified & MODIFIED_REMOTEADDR) {
1825                         strlcpy(gres->hr_remoteaddr, res->hr_remoteaddr,
1826                             sizeof(gres->hr_remoteaddr));
1827                 }
1828         }
1829 #undef  MODIFIED_REMOTEADDR
1830 #undef  MODIFIED_REPLICATION
1831 #undef  MODIFIED_TIMEOUT
1832 #undef  MODIFIED_EXEC
1833
1834         pjdlog_info("Configuration reloaded successfully.");
1835         return;
1836 failed:
1837         if (newcfg != NULL) {
1838                 if (newcfg->hc_controlconn != NULL)
1839                         proto_close(newcfg->hc_controlconn);
1840                 if (newcfg->hc_listenconn != NULL)
1841                         proto_close(newcfg->hc_listenconn);
1842                 yy_config_free(newcfg);
1843         }
1844         pjdlog_warning("Configuration not reloaded.");
1845 }
1846
1847 static void
1848 keepalive_send(struct hast_resource *res, unsigned int ncomp)
1849 {
1850         struct nv *nv;
1851
1852         nv = nv_alloc();
1853         nv_add_uint8(nv, HIO_KEEPALIVE, "cmd");
1854         if (nv_error(nv) != 0) {
1855                 nv_free(nv);
1856                 pjdlog_debug(1,
1857                     "keepalive_send: Unable to prepare header to send.");
1858                 return;
1859         }
1860         if (hast_proto_send(res, res->hr_remoteout, nv, NULL, 0) < 0) {
1861                 pjdlog_common(LOG_DEBUG, 1, errno,
1862                     "keepalive_send: Unable to send request");
1863                 nv_free(nv);
1864                 rw_unlock(&hio_remote_lock[ncomp]);
1865                 remote_close(res, ncomp);
1866                 rw_rlock(&hio_remote_lock[ncomp]);
1867                 return;
1868         }
1869         nv_free(nv);
1870         pjdlog_debug(2, "keepalive_send: Request sent.");
1871 }
1872
1873 static void
1874 guard_one(struct hast_resource *res, unsigned int ncomp)
1875 {
1876         struct proto_conn *in, *out;
1877
1878         if (!ISREMOTE(ncomp))
1879                 return;
1880
1881         rw_rlock(&hio_remote_lock[ncomp]);
1882
1883         if (!real_remote(res)) {
1884                 rw_unlock(&hio_remote_lock[ncomp]);
1885                 return;
1886         }
1887
1888         if (ISCONNECTED(res, ncomp)) {
1889                 assert(res->hr_remotein != NULL);
1890                 assert(res->hr_remoteout != NULL);
1891                 keepalive_send(res, ncomp);
1892         }
1893
1894         if (ISCONNECTED(res, ncomp)) {
1895                 assert(res->hr_remotein != NULL);
1896                 assert(res->hr_remoteout != NULL);
1897                 rw_unlock(&hio_remote_lock[ncomp]);
1898                 pjdlog_debug(2, "remote_guard: Connection to %s is ok.",
1899                     res->hr_remoteaddr);
1900                 return;
1901         }
1902
1903         assert(res->hr_remotein == NULL);
1904         assert(res->hr_remoteout == NULL);
1905         /*
1906          * Upgrade the lock. It doesn't have to be atomic as no other thread
1907          * can change connection status from disconnected to connected.
1908          */
1909         rw_unlock(&hio_remote_lock[ncomp]);
1910         pjdlog_debug(2, "remote_guard: Reconnecting to %s.",
1911             res->hr_remoteaddr);
1912         in = out = NULL;
1913         if (init_remote(res, &in, &out)) {
1914                 rw_wlock(&hio_remote_lock[ncomp]);
1915                 assert(res->hr_remotein == NULL);
1916                 assert(res->hr_remoteout == NULL);
1917                 assert(in != NULL && out != NULL);
1918                 res->hr_remotein = in;
1919                 res->hr_remoteout = out;
1920                 rw_unlock(&hio_remote_lock[ncomp]);
1921                 pjdlog_info("Successfully reconnected to %s.",
1922                     res->hr_remoteaddr);
1923                 sync_start();
1924         } else {
1925                 /* Both connections should be NULL. */
1926                 assert(res->hr_remotein == NULL);
1927                 assert(res->hr_remoteout == NULL);
1928                 assert(in == NULL && out == NULL);
1929                 pjdlog_debug(2, "remote_guard: Reconnect to %s failed.",
1930                     res->hr_remoteaddr);
1931         }
1932 }
1933
1934 /*
1935  * Thread guards remote connections and reconnects when needed, handles
1936  * signals, etc.
1937  */
1938 static void *
1939 guard_thread(void *arg)
1940 {
1941         struct hast_resource *res = arg;
1942         unsigned int ii, ncomps;
1943         struct timespec timeout;
1944         time_t lastcheck, now;
1945         sigset_t mask;
1946         int signo;
1947
1948         ncomps = HAST_NCOMPONENTS;
1949         lastcheck = time(NULL);
1950
1951         PJDLOG_VERIFY(sigemptyset(&mask) == 0);
1952         PJDLOG_VERIFY(sigaddset(&mask, SIGHUP) == 0);
1953         PJDLOG_VERIFY(sigaddset(&mask, SIGINT) == 0);
1954         PJDLOG_VERIFY(sigaddset(&mask, SIGTERM) == 0);
1955
1956         timeout.tv_nsec = 0;
1957         signo = -1;
1958
1959         for (;;) {
1960                 switch (signo) {
1961                 case SIGHUP:
1962                         config_reload();
1963                         break;
1964                 case SIGINT:
1965                 case SIGTERM:
1966                         sigexit_received = true;
1967                         primary_exitx(EX_OK,
1968                             "Termination signal received, exiting.");
1969                         break;
1970                 default:
1971                         break;
1972                 }
1973
1974                 pjdlog_debug(2, "remote_guard: Checking connections.");
1975                 now = time(NULL);
1976                 if (lastcheck + RETRY_SLEEP <= now) {
1977                         for (ii = 0; ii < ncomps; ii++)
1978                                 guard_one(res, ii);
1979                         lastcheck = now;
1980                 }
1981                 timeout.tv_sec = RETRY_SLEEP;
1982                 signo = sigtimedwait(&mask, NULL, &timeout);
1983         }
1984         /* NOTREACHED */
1985         return (NULL);
1986 }