/*- * Copyright (c) 2009-2010 The FreeBSD Foundation * Copyright (c) 2010 Pawel Jakub Dawidek * All rights reserved. * * This software was developed by Pawel Jakub Dawidek under sponsorship from * the FreeBSD Foundation. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "control.h" #include "event.h" #include "hast.h" #include "hast_proto.h" #include "hastd.h" #include "hooks.h" #include "metadata.h" #include "proto.h" #include "subr.h" #include "synch.h" struct hio { uint64_t hio_seq; int hio_error; struct nv *hio_nv; void *hio_data; uint8_t hio_cmd; uint64_t hio_offset; uint64_t hio_length; TAILQ_ENTRY(hio) hio_next; }; static struct hast_resource *gres; /* * Free list holds unused structures. When free list is empty, we have to wait * until some in-progress requests are freed. */ static TAILQ_HEAD(, hio) hio_free_list; static pthread_mutex_t hio_free_list_lock; static pthread_cond_t hio_free_list_cond; /* * Disk thread (the one that do I/O requests) takes requests from this list. */ static TAILQ_HEAD(, hio) hio_disk_list; static pthread_mutex_t hio_disk_list_lock; static pthread_cond_t hio_disk_list_cond; /* * There is one recv list for every component, although local components don't * use recv lists as local requests are done synchronously. */ static TAILQ_HEAD(, hio) hio_send_list; static pthread_mutex_t hio_send_list_lock; static pthread_cond_t hio_send_list_cond; /* * Maximum number of outstanding I/O requests. */ #define HAST_HIO_MAX 256 static void *recv_thread(void *arg); static void *disk_thread(void *arg); static void *send_thread(void *arg); #define QUEUE_INSERT(name, hio) do { \ bool _wakeup; \ \ mtx_lock(&hio_##name##_list_lock); \ _wakeup = TAILQ_EMPTY(&hio_##name##_list); \ TAILQ_INSERT_TAIL(&hio_##name##_list, (hio), hio_next); \ mtx_unlock(&hio_##name##_list_lock); \ if (_wakeup) \ cv_signal(&hio_##name##_list_cond); \ } while (0) #define QUEUE_TAKE(name, hio) do { \ mtx_lock(&hio_##name##_list_lock); \ while (((hio) = TAILQ_FIRST(&hio_##name##_list)) == NULL) { \ cv_wait(&hio_##name##_list_cond, \ &hio_##name##_list_lock); \ } \ TAILQ_REMOVE(&hio_##name##_list, (hio), hio_next); \ mtx_unlock(&hio_##name##_list_lock); \ } while (0) static void init_environment(void) { struct hio *hio; unsigned int ii; /* * Initialize lists, their locks and theirs condition variables. */ TAILQ_INIT(&hio_free_list); mtx_init(&hio_free_list_lock); cv_init(&hio_free_list_cond); TAILQ_INIT(&hio_disk_list); mtx_init(&hio_disk_list_lock); cv_init(&hio_disk_list_cond); TAILQ_INIT(&hio_send_list); mtx_init(&hio_send_list_lock); cv_init(&hio_send_list_cond); /* * Allocate requests pool and initialize requests. */ for (ii = 0; ii < HAST_HIO_MAX; ii++) { hio = malloc(sizeof(*hio)); if (hio == NULL) { pjdlog_exitx(EX_TEMPFAIL, "Unable to allocate memory (%zu bytes) for hio request.", sizeof(*hio)); } hio->hio_error = 0; hio->hio_data = malloc(MAXPHYS); if (hio->hio_data == NULL) { pjdlog_exitx(EX_TEMPFAIL, "Unable to allocate memory (%zu bytes) for gctl_data.", (size_t)MAXPHYS); } TAILQ_INSERT_HEAD(&hio_free_list, hio, hio_next); } } static void init_local(struct hast_resource *res) { if (metadata_read(res, true) < 0) exit(EX_NOINPUT); } static void init_remote(struct hast_resource *res, struct nv *nvin) { uint64_t resuid; struct nv *nvout; unsigned char *map; size_t mapsize; /* Setup direction. */ if (proto_send(res->hr_remoteout, NULL, 0) == -1) pjdlog_errno(LOG_WARNING, "Unable to set connection direction"); map = NULL; mapsize = 0; nvout = nv_alloc(); nv_add_int64(nvout, (int64_t)res->hr_datasize, "datasize"); nv_add_int32(nvout, (int32_t)res->hr_extentsize, "extentsize"); resuid = nv_get_uint64(nvin, "resuid"); res->hr_primary_localcnt = nv_get_uint64(nvin, "localcnt"); res->hr_primary_remotecnt = nv_get_uint64(nvin, "remotecnt"); nv_add_uint64(nvout, res->hr_secondary_localcnt, "localcnt"); nv_add_uint64(nvout, res->hr_secondary_remotecnt, "remotecnt"); mapsize = activemap_calc_ondisk_size(res->hr_local_mediasize - METADATA_SIZE, res->hr_extentsize, res->hr_local_sectorsize); map = malloc(mapsize); if (map == NULL) { pjdlog_exitx(EX_TEMPFAIL, "Unable to allocate memory (%zu bytes) for activemap.", mapsize); } /* * When we work as primary and secondary is missing we will increase * localcnt in our metadata. When secondary is connected and synced * we make localcnt be equal to remotecnt, which means nodes are more * or less in sync. * Split-brain condition is when both nodes are not able to communicate * and are both configured as primary nodes. In turn, they can both * make incompatible changes to the data and we have to detect that. * Under split-brain condition we will increase our localcnt on first * write and remote node will increase its localcnt on first write. * When we connect we can see that primary's localcnt is greater than * our remotecnt (primary was modified while we weren't watching) and * our localcnt is greater than primary's remotecnt (we were modified * while primary wasn't watching). * There are many possible combinations which are all gathered below. * Don't pay too much attention to exact numbers, the more important * is to compare them. We compare secondary's local with primary's * remote and secondary's remote with primary's local. * Note that every case where primary's localcnt is smaller than * secondary's remotecnt and where secondary's localcnt is smaller than * primary's remotecnt should be impossible in practise. We will perform * full synchronization then. Those cases are marked with an asterisk. * Regular synchronization means that only extents marked as dirty are * synchronized (regular synchronization). * * SECONDARY METADATA PRIMARY METADATA * local=3 remote=3 local=2 remote=2* ?! Full sync from secondary. * local=3 remote=3 local=2 remote=3* ?! Full sync from primary. * local=3 remote=3 local=2 remote=4* ?! Full sync from primary. * local=3 remote=3 local=3 remote=2 Primary is out-of-date, * regular sync from secondary. * local=3 remote=3 local=3 remote=3 Regular sync just in case. * local=3 remote=3 local=3 remote=4* ?! Full sync from primary. * local=3 remote=3 local=4 remote=2 Split-brain condition. * local=3 remote=3 local=4 remote=3 Secondary out-of-date, * regular sync from primary. * local=3 remote=3 local=4 remote=4* ?! Full sync from primary. */ if (res->hr_resuid == 0) { /* * Provider is used for the first time. If primary node done no * writes yet as well (we will find "virgin" argument) then * there is no need to synchronize anything. If primary node * done any writes already we have to synchronize everything. */ PJDLOG_ASSERT(res->hr_secondary_localcnt == 0); res->hr_resuid = resuid; if (metadata_write(res) < 0) exit(EX_NOINPUT); if (nv_exists(nvin, "virgin")) { free(map); map = NULL; mapsize = 0; } else { memset(map, 0xff, mapsize); } nv_add_int8(nvout, 1, "virgin"); nv_add_uint8(nvout, HAST_SYNCSRC_PRIMARY, "syncsrc"); } else if (res->hr_resuid != resuid) { char errmsg[256]; (void)snprintf(errmsg, sizeof(errmsg), "Resource unique ID mismatch (primary=%ju, secondary=%ju).", (uintmax_t)resuid, (uintmax_t)res->hr_resuid); pjdlog_error("%s", errmsg); nv_add_string(nvout, errmsg, "errmsg"); if (hast_proto_send(res, res->hr_remotein, nvout, NULL, 0) < 0) { pjdlog_exit(EX_TEMPFAIL, "Unable to send response to %s", res->hr_remoteaddr); } nv_free(nvout); exit(EX_CONFIG); } else if ( /* Is primary is out-of-date? */ (res->hr_secondary_localcnt > res->hr_primary_remotecnt && res->hr_secondary_remotecnt == res->hr_primary_localcnt) || /* Nodes are more or less in sync? */ (res->hr_secondary_localcnt == res->hr_primary_remotecnt && res->hr_secondary_remotecnt == res->hr_primary_localcnt) || /* Is secondary is out-of-date? */ (res->hr_secondary_localcnt == res->hr_primary_remotecnt && res->hr_secondary_remotecnt < res->hr_primary_localcnt)) { /* * Nodes are more or less in sync or one of the nodes is * out-of-date. * It doesn't matter at this point which one, we just have to * send out local bitmap to the remote node. */ if (pread(res->hr_localfd, map, mapsize, METADATA_SIZE) != (ssize_t)mapsize) { pjdlog_exit(LOG_ERR, "Unable to read activemap"); } if (res->hr_secondary_localcnt > res->hr_primary_remotecnt && res->hr_secondary_remotecnt == res->hr_primary_localcnt) { /* Primary is out-of-date, sync from secondary. */ nv_add_uint8(nvout, HAST_SYNCSRC_SECONDARY, "syncsrc"); } else { /* * Secondary is out-of-date or counts match. * Sync from primary. */ nv_add_uint8(nvout, HAST_SYNCSRC_PRIMARY, "syncsrc"); } } else if (res->hr_secondary_localcnt > res->hr_primary_remotecnt && res->hr_primary_localcnt > res->hr_secondary_remotecnt) { /* * Not good, we have split-brain condition. */ pjdlog_error("Split-brain detected, exiting."); nv_add_string(nvout, "Split-brain condition!", "errmsg"); free(map); map = NULL; mapsize = 0; } else /* if (res->hr_secondary_localcnt < res->hr_primary_remotecnt || res->hr_primary_localcnt < res->hr_secondary_remotecnt) */ { /* * This should never happen in practise, but we will perform * full synchronization. */ PJDLOG_ASSERT(res->hr_secondary_localcnt < res->hr_primary_remotecnt || res->hr_primary_localcnt < res->hr_secondary_remotecnt); mapsize = activemap_calc_ondisk_size(res->hr_local_mediasize - METADATA_SIZE, res->hr_extentsize, res->hr_local_sectorsize); memset(map, 0xff, mapsize); if (res->hr_secondary_localcnt > res->hr_primary_remotecnt) { /* In this one of five cases sync from secondary. */ nv_add_uint8(nvout, HAST_SYNCSRC_SECONDARY, "syncsrc"); } else { /* For the rest four cases sync from primary. */ nv_add_uint8(nvout, HAST_SYNCSRC_PRIMARY, "syncsrc"); } pjdlog_warning("This should never happen, asking for full synchronization (primary(local=%ju, remote=%ju), secondary(local=%ju, remote=%ju)).", (uintmax_t)res->hr_primary_localcnt, (uintmax_t)res->hr_primary_remotecnt, (uintmax_t)res->hr_secondary_localcnt, (uintmax_t)res->hr_secondary_remotecnt); } nv_add_uint32(nvout, (uint32_t)mapsize, "mapsize"); if (hast_proto_send(res, res->hr_remotein, nvout, map, mapsize) < 0) { pjdlog_exit(EX_TEMPFAIL, "Unable to send activemap to %s", res->hr_remoteaddr); } if (map != NULL) free(map); nv_free(nvout); /* Setup direction. */ if (proto_recv(res->hr_remotein, NULL, 0) == -1) pjdlog_errno(LOG_WARNING, "Unable to set connection direction"); if (res->hr_secondary_localcnt > res->hr_primary_remotecnt && res->hr_primary_localcnt > res->hr_secondary_remotecnt) { /* Exit on split-brain. */ event_send(res, EVENT_SPLITBRAIN); exit(EX_CONFIG); } } void hastd_secondary(struct hast_resource *res, struct nv *nvin) { sigset_t mask; pthread_t td; pid_t pid; int error, mode, debuglevel; /* * Create communication channel between parent and child. */ if (proto_client(NULL, "socketpair://", &res->hr_ctrl) < 0) { KEEP_ERRNO((void)pidfile_remove(pfh)); pjdlog_exit(EX_OSERR, "Unable to create control sockets between parent and child"); } /* * Create communication channel between child and parent. */ if (proto_client(NULL, "socketpair://", &res->hr_event) < 0) { KEEP_ERRNO((void)pidfile_remove(pfh)); pjdlog_exit(EX_OSERR, "Unable to create event sockets between child and parent"); } pid = fork(); if (pid < 0) { KEEP_ERRNO((void)pidfile_remove(pfh)); pjdlog_exit(EX_OSERR, "Unable to fork"); } if (pid > 0) { /* This is parent. */ proto_close(res->hr_remotein); res->hr_remotein = NULL; proto_close(res->hr_remoteout); res->hr_remoteout = NULL; /* Declare that we are receiver. */ proto_recv(res->hr_event, NULL, 0); /* Declare that we are sender. */ proto_send(res->hr_ctrl, NULL, 0); res->hr_workerpid = pid; return; } gres = res; mode = pjdlog_mode_get(); debuglevel = pjdlog_debug_get(); /* Declare that we are sender. */ proto_send(res->hr_event, NULL, 0); /* Declare that we are receiver. */ proto_recv(res->hr_ctrl, NULL, 0); descriptors_cleanup(res); descriptors_assert(res, mode); pjdlog_init(mode); pjdlog_debug_set(debuglevel); pjdlog_prefix_set("[%s] (%s) ", res->hr_name, role2str(res->hr_role)); setproctitle("%s (%s)", res->hr_name, role2str(res->hr_role)); PJDLOG_VERIFY(sigemptyset(&mask) == 0); PJDLOG_VERIFY(sigprocmask(SIG_SETMASK, &mask, NULL) == 0); /* Error in setting timeout is not critical, but why should it fail? */ if (proto_timeout(res->hr_remotein, 2 * HAST_KEEPALIVE) < 0) pjdlog_errno(LOG_WARNING, "Unable to set connection timeout"); if (proto_timeout(res->hr_remoteout, res->hr_timeout) < 0) pjdlog_errno(LOG_WARNING, "Unable to set connection timeout"); init_local(res); init_environment(); if (drop_privs(res) != 0) exit(EX_CONFIG); pjdlog_info("Privileges successfully dropped."); /* * Create the control thread before sending any event to the parent, * as we can deadlock when parent sends control request to worker, * but worker has no control thread started yet, so parent waits. * In the meantime worker sends an event to the parent, but parent * is unable to handle the event, because it waits for control * request response. */ error = pthread_create(&td, NULL, ctrl_thread, res); PJDLOG_ASSERT(error == 0); init_remote(res, nvin); event_send(res, EVENT_CONNECT); error = pthread_create(&td, NULL, recv_thread, res); PJDLOG_ASSERT(error == 0); error = pthread_create(&td, NULL, disk_thread, res); PJDLOG_ASSERT(error == 0); (void)send_thread(res); } static void reqlog(int loglevel, int debuglevel, int error, struct hio *hio, const char *fmt, ...) { char msg[1024]; va_list ap; int len; va_start(ap, fmt); len = vsnprintf(msg, sizeof(msg), fmt, ap); va_end(ap); if ((size_t)len < sizeof(msg)) { switch (hio->hio_cmd) { case HIO_READ: (void)snprintf(msg + len, sizeof(msg) - len, "READ(%ju, %ju).", (uintmax_t)hio->hio_offset, (uintmax_t)hio->hio_length); break; case HIO_DELETE: (void)snprintf(msg + len, sizeof(msg) - len, "DELETE(%ju, %ju).", (uintmax_t)hio->hio_offset, (uintmax_t)hio->hio_length); break; case HIO_FLUSH: (void)snprintf(msg + len, sizeof(msg) - len, "FLUSH."); break; case HIO_WRITE: (void)snprintf(msg + len, sizeof(msg) - len, "WRITE(%ju, %ju).", (uintmax_t)hio->hio_offset, (uintmax_t)hio->hio_length); break; case HIO_KEEPALIVE: (void)snprintf(msg + len, sizeof(msg) - len, "KEEPALIVE."); break; default: (void)snprintf(msg + len, sizeof(msg) - len, "UNKNOWN(%u).", (unsigned int)hio->hio_cmd); break; } } pjdlog_common(loglevel, debuglevel, error, "%s", msg); } static int requnpack(struct hast_resource *res, struct hio *hio) { hio->hio_cmd = nv_get_uint8(hio->hio_nv, "cmd"); if (hio->hio_cmd == 0) { pjdlog_error("Header contains no 'cmd' field."); hio->hio_error = EINVAL; goto end; } switch (hio->hio_cmd) { case HIO_FLUSH: case HIO_KEEPALIVE: break; case HIO_READ: case HIO_WRITE: case HIO_DELETE: hio->hio_offset = nv_get_uint64(hio->hio_nv, "offset"); if (nv_error(hio->hio_nv) != 0) { pjdlog_error("Header is missing 'offset' field."); hio->hio_error = EINVAL; goto end; } hio->hio_length = nv_get_uint64(hio->hio_nv, "length"); if (nv_error(hio->hio_nv) != 0) { pjdlog_error("Header is missing 'length' field."); hio->hio_error = EINVAL; goto end; } if (hio->hio_length == 0) { pjdlog_error("Data length is zero."); hio->hio_error = EINVAL; goto end; } if (hio->hio_length > MAXPHYS) { pjdlog_error("Data length is too large (%ju > %ju).", (uintmax_t)hio->hio_length, (uintmax_t)MAXPHYS); hio->hio_error = EINVAL; goto end; } if ((hio->hio_offset % res->hr_local_sectorsize) != 0) { pjdlog_error("Offset %ju is not multiple of sector size.", (uintmax_t)hio->hio_offset); hio->hio_error = EINVAL; goto end; } if ((hio->hio_length % res->hr_local_sectorsize) != 0) { pjdlog_error("Length %ju is not multiple of sector size.", (uintmax_t)hio->hio_length); hio->hio_error = EINVAL; goto end; } if (hio->hio_offset + hio->hio_length > (uint64_t)res->hr_datasize) { pjdlog_error("Data offset is too large (%ju > %ju).", (uintmax_t)(hio->hio_offset + hio->hio_length), (uintmax_t)res->hr_datasize); hio->hio_error = EINVAL; goto end; } break; default: pjdlog_error("Header contains invalid 'cmd' (%hhu).", hio->hio_cmd); hio->hio_error = EINVAL; goto end; } hio->hio_error = 0; end: return (hio->hio_error); } static __dead2 void secondary_exit(int exitcode, const char *fmt, ...) { va_list ap; PJDLOG_ASSERT(exitcode != EX_OK); va_start(ap, fmt); pjdlogv_errno(LOG_ERR, fmt, ap); va_end(ap); event_send(gres, EVENT_DISCONNECT); exit(exitcode); } /* * Thread receives requests from the primary node. */ static void * recv_thread(void *arg) { struct hast_resource *res = arg; struct hio *hio; for (;;) { pjdlog_debug(2, "recv: Taking free request."); QUEUE_TAKE(free, hio); pjdlog_debug(2, "recv: (%p) Got request.", hio); if (hast_proto_recv_hdr(res->hr_remotein, &hio->hio_nv) < 0) { secondary_exit(EX_TEMPFAIL, "Unable to receive request header"); } if (requnpack(res, hio) != 0) { pjdlog_debug(2, "recv: (%p) Moving request to the send queue.", hio); QUEUE_INSERT(send, hio); continue; } switch (hio->hio_cmd) { case HIO_READ: res->hr_stat_read++; break; case HIO_WRITE: res->hr_stat_write++; break; case HIO_DELETE: res->hr_stat_delete++; break; case HIO_FLUSH: res->hr_stat_flush++; break; } reqlog(LOG_DEBUG, 2, -1, hio, "recv: (%p) Got request header: ", hio); if (hio->hio_cmd == HIO_KEEPALIVE) { pjdlog_debug(2, "recv: (%p) Moving request to the free queue.", hio); nv_free(hio->hio_nv); QUEUE_INSERT(free, hio); continue; } else if (hio->hio_cmd == HIO_WRITE) { if (hast_proto_recv_data(res, res->hr_remotein, hio->hio_nv, hio->hio_data, MAXPHYS) < 0) { secondary_exit(EX_TEMPFAIL, "Unable to receive request data"); } } pjdlog_debug(2, "recv: (%p) Moving request to the disk queue.", hio); QUEUE_INSERT(disk, hio); } /* NOTREACHED */ return (NULL); } /* * Thread reads from or writes to local component and also handles DELETE and * FLUSH requests. */ static void * disk_thread(void *arg) { struct hast_resource *res = arg; struct hio *hio; ssize_t ret; bool clear_activemap; clear_activemap = true; for (;;) { pjdlog_debug(2, "disk: Taking request."); QUEUE_TAKE(disk, hio); while (clear_activemap) { unsigned char *map; size_t mapsize; /* * When first request is received, it means that primary * already received our activemap, merged it and stored * locally. We can now safely clear our activemap. */ mapsize = activemap_calc_ondisk_size(res->hr_local_mediasize - METADATA_SIZE, res->hr_extentsize, res->hr_local_sectorsize); map = calloc(1, mapsize); if (map == NULL) { pjdlog_warning("Unable to allocate memory to clear local activemap."); break; } if (pwrite(res->hr_localfd, map, mapsize, METADATA_SIZE) != (ssize_t)mapsize) { pjdlog_errno(LOG_WARNING, "Unable to store cleared activemap"); free(map); break; } free(map); clear_activemap = false; pjdlog_debug(1, "Local activemap cleared."); } reqlog(LOG_DEBUG, 2, -1, hio, "disk: (%p) Got request: ", hio); /* Handle the actual request. */ switch (hio->hio_cmd) { case HIO_READ: ret = pread(res->hr_localfd, hio->hio_data, hio->hio_length, hio->hio_offset + res->hr_localoff); if (ret < 0) hio->hio_error = errno; else if (ret != (int64_t)hio->hio_length) hio->hio_error = EIO; else hio->hio_error = 0; break; case HIO_WRITE: ret = pwrite(res->hr_localfd, hio->hio_data, hio->hio_length, hio->hio_offset + res->hr_localoff); if (ret < 0) hio->hio_error = errno; else if (ret != (int64_t)hio->hio_length) hio->hio_error = EIO; else hio->hio_error = 0; break; case HIO_DELETE: ret = g_delete(res->hr_localfd, hio->hio_offset + res->hr_localoff, hio->hio_length); if (ret < 0) hio->hio_error = errno; else hio->hio_error = 0; break; case HIO_FLUSH: ret = g_flush(res->hr_localfd); if (ret < 0) hio->hio_error = errno; else hio->hio_error = 0; break; } if (hio->hio_error != 0) { reqlog(LOG_ERR, 0, hio->hio_error, hio, "Request failed: "); } pjdlog_debug(2, "disk: (%p) Moving request to the send queue.", hio); QUEUE_INSERT(send, hio); } /* NOTREACHED */ return (NULL); } /* * Thread sends requests back to primary node. */ static void * send_thread(void *arg) { struct hast_resource *res = arg; struct nv *nvout; struct hio *hio; void *data; size_t length; for (;;) { pjdlog_debug(2, "send: Taking request."); QUEUE_TAKE(send, hio); reqlog(LOG_DEBUG, 2, -1, hio, "send: (%p) Got request: ", hio); nvout = nv_alloc(); /* Copy sequence number. */ nv_add_uint64(nvout, nv_get_uint64(hio->hio_nv, "seq"), "seq"); switch (hio->hio_cmd) { case HIO_READ: if (hio->hio_error == 0) { data = hio->hio_data; length = hio->hio_length; break; } /* * We send no data in case of an error. */ /* FALLTHROUGH */ case HIO_DELETE: case HIO_FLUSH: case HIO_WRITE: data = NULL; length = 0; break; default: abort(); break; } if (hio->hio_error != 0) nv_add_int16(nvout, hio->hio_error, "error"); if (hast_proto_send(res, res->hr_remoteout, nvout, data, length) < 0) { secondary_exit(EX_TEMPFAIL, "Unable to send reply."); } nv_free(nvout); pjdlog_debug(2, "send: (%p) Moving request to the free queue.", hio); nv_free(hio->hio_nv); hio->hio_error = 0; QUEUE_INSERT(free, hio); } /* NOTREACHED */ return (NULL); }