static void shm_queue_init(void)
{
int ret;
shmfd = open(shmfile, O_CREAT | O_RDWR, 0644);
if (shmfd < 0)
panic("cannot open shared file, %s\n", shmfile);
shm_queue_lock();
ret = ftruncate(shmfd, sizeof(*shm_queue));
assert(ret == 0);
shm_queue = mmap(0, sizeof(*shm_queue),
PROT_READ | PROT_WRITE, MAP_SHARED, shmfd, 0);
assert(shm_queue != MAP_FAILED);
if (is_shm_queue_valid())
event_pos = shm_queue->pos;
else {
/* initialize shared memory */
event_pos = 0;
ret = ftruncate(shmfd, 0);
assert(ret == 0);
ret = ftruncate(shmfd, sizeof(*shm_queue));
assert(ret == 0);
shm_queue_set_chksum();
}
shm_queue_unlock();
}
/*
* Returns true if an event is processed
*/
static bool local_process_event(void)
{
struct local_event *ev;
enum cluster_join_result res;
ev = shm_queue_peek();
if (!ev)
return false;
switch (ev->type) {
case EVENT_JOIN_REQUEST:
if (!node_eq(&ev->nodes[0], &this_node))
return false;
res = sd_check_join_cb(&ev->sender, ev->buf);
ev->join_result = res;
ev->type = EVENT_JOIN_RESPONSE;
msync(ev, sizeof(*ev), MS_SYNC);
shm_queue_notify();
if (res == CJ_RES_MASTER_TRANSFER) {
eprintf("failed to join sheepdog cluster: "
"please retry when master is up\n");
shm_queue_unlock();
exit(1);
}
return false;
case EVENT_JOIN_RESPONSE:
if (ev->join_result == CJ_RES_MASTER_TRANSFER) {
/* FIXME: This code is tricky, but Sheepdog assumes that */
/* nr_nodes = 1 when join_result = MASTER_TRANSFER... */
ev->nr_nodes = 1;
ev->nodes[0] = this_node;
ev->pids[0] = getpid();
shm_queue_set_chksum();
}
sd_join_handler(&ev->sender, ev->nodes, ev->nr_nodes,
ev->join_result, ev->buf);
shm_queue_pop();
break;
case EVENT_LEAVE:
sd_leave_handler(&ev->sender, ev->nodes, ev->nr_nodes);
shm_queue_pop();
break;
case EVENT_BLOCK:
sd_block_handler(&ev->sender);
return false;
case EVENT_NOTIFY:
sd_notify_handler(&ev->sender, ev->buf, ev->buf_len);
shm_queue_pop();
break;
}
return true;
}
static void shm_queue_notify(void)
{
int i;
size_t nr;
pid_t pids[SD_MAX_NODES];
shm_queue_set_chksum();
nr = get_nodes(NULL, pids);
for (i = 0; i < nr; i++)
kill(pids[i], SIGUSR1);
}
static int local_dispatch(void)
{
int ret;
struct signalfd_siginfo siginfo;
struct local_event *ev;
enum cluster_join_result res;
static struct work work = {
.fn = local_block,
.done = local_block_done,
};
dprintf("read siginfo\n");
ret = read(sigfd, &siginfo, sizeof(siginfo));
assert(ret == sizeof(siginfo));
shm_queue_lock();
ev = shm_queue_peek();
if (!ev)
goto out;
switch (ev->type) {
case EVENT_JOIN:
if (ev->blocked) {
if (node_cmp(&ev->nodes[0], &this_node) == 0) {
res = local_check_join_cb(&ev->sender, ev->buf);
ev->join_result = res;
ev->blocked = 0;
msync(ev, sizeof(*ev), MS_SYNC);
shm_queue_notify();
if (res == CJ_RES_MASTER_TRANSFER) {
eprintf("failed to join sheepdog cluster: please retry when master is up\n");
shm_queue_unlock();
exit(1);
}
}
goto out;
}
if (ev->join_result == CJ_RES_MASTER_TRANSFER) {
/* FIXME: This code is tricky, but Sheepdog assumes that */
/* nr_nodes = 1 when join_result = MASTER_TRANSFER... */
ev->nr_nodes = 1;
ev->nodes[0] = this_node;
ev->pids[0] = getpid();
shm_queue_set_chksum();
}
lhdlrs.join_handler(&ev->sender, ev->nodes, ev->nr_nodes,
ev->join_result, ev->buf);
break;
case EVENT_LEAVE:
lhdlrs.leave_handler(&ev->sender, ev->nodes, ev->nr_nodes);
break;
case EVENT_NOTIFY:
if (ev->blocked) {
if (node_cmp(&ev->sender, &this_node) == 0) {
if (!ev->callbacked) {
queue_work(local_block_wq, &work);
ev->callbacked = 1;
}
}
goto out;
}
lhdlrs.notify_handler(&ev->sender, ev->buf, ev->buf_len);
break;
}
shm_queue_pop();
out:
shm_queue_unlock();
return 0;
}
