vitastor/osd_receive.cpp

#include "osd.h"

bool osd_t::try_receive(osd_client_t & cl)
{
    int peer_fd = cl.peer_fd;
    io_uring_sqe* sqe = ringloop->get_sqe();
    if (!sqe)
    {
        return false;
    }
    ring_data_t* data = ((ring_data_t*)sqe->user_data);
    if (!cl.read_buf)
    {
        // no reads in progress
        // so this is either a new command or a reply to a previously sent command
        if (!cl.read_op)
        {
            cl.read_op = new osd_op_t;
            cl.read_op->peer_fd = peer_fd;
        }
        cl.read_op->op_type = OSD_OP_IN;
        cl.read_buf = &cl.read_op->req.buf;
        cl.read_remaining = OSD_PACKET_SIZE;
        cl.read_state = CL_READ_OP;
    }
    cl.read_iov.iov_base = cl.read_buf;
    cl.read_iov.iov_len = cl.read_remaining;
    cl.read_msg.msg_iov = &cl.read_iov;
    cl.read_msg.msg_iovlen = 1;
    data->callback = [this, peer_fd](ring_data_t *data) { handle_read(data, peer_fd); };
    my_uring_prep_recvmsg(sqe, peer_fd, &cl.read_msg, 0);
    return true;
}

void osd_t::read_requests()
{
    for (auto & p: clients)
    {
        if (p.second.peer_state == PEER_CONNECTED && p.second.read_iov.iov_len == 0)
        {
            try_receive(p.second);
        }
    }
}

void osd_t::handle_read(ring_data_t *data, int peer_fd)
{
    auto cl_it = clients.find(peer_fd);
    if (cl_it != clients.end())
    {
        auto & cl = cl_it->second;
        cl.read_iov.iov_len = 0;
        if (data->res == -EAGAIN)
        {
            return;
        }
        else if (data->res < 0)
        {
            // this is a client socket, so don't panic. just disconnect it
            printf("Client %d socket read error: %d (%s). Disconnecting client\n", peer_fd, -data->res, strerror(-data->res));
            stop_client(peer_fd);
            return;
        }
        if (data->res > 0)
        {
            cl.read_remaining -= data->res;
            cl.read_buf += data->res;
            if (cl.read_remaining <= 0)
            {
                cl.read_buf = NULL;
                if (cl.read_state == CL_READ_OP)
                {
                    if (cl.read_op->req.hdr.magic == SECONDARY_OSD_REPLY_MAGIC)
                    {
                        handle_reply_hdr(&cl);
                    }
                    else
                    {
                        handle_op_hdr(&cl);
                    }
                }
                else if (cl.read_state == CL_READ_DATA)
                {
                    // Operation is ready
                    exec_op(cl.read_op);
                    cl.read_op = NULL;
                    cl.read_state = 0;
                }
                else if (cl.read_state == CL_READ_REPLY_DATA)
                {
                    // Reply is ready
                    auto req_it = cl.sent_ops.find(cl.read_reply_id);
                    osd_op_t *request = req_it->second;
                    cl.sent_ops.erase(req_it);
                    cl.read_reply_id = 0;
                    cl.read_state = 0;
                    // Measure subop latency
                    timeval tv_end;
                    gettimeofday(&tv_end, NULL);
                    subop_stat_count[request->req.hdr.opcode]++;
                    subop_stat_sum[request->req.hdr.opcode] += (
                        (tv_end.tv_sec - request->tv_begin.tv_sec)*1000000 +
                        tv_end.tv_usec - request->tv_begin.tv_usec
                    );
                    request->callback(request);
                }
            }
        }
    }
}

void osd_t::handle_op_hdr(osd_client_t *cl)
{
    osd_op_t *cur_op = cl->read_op;
    if (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_READ)
    {
        if (cur_op->req.sec_rw.len > 0)
            cur_op->buf = memalign(512, cur_op->req.sec_rw.len);
        cl->read_remaining = 0;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_WRITE)
    {
        if (cur_op->req.sec_rw.len > 0)
            cur_op->buf = memalign(512, cur_op->req.sec_rw.len);
        cl->read_remaining = cur_op->req.sec_rw.len;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_SECONDARY_STABILIZE ||
        cur_op->req.hdr.opcode == OSD_OP_SECONDARY_ROLLBACK)
    {
        if (cur_op->req.sec_stab.len > 0)
            cur_op->buf = memalign(512, cur_op->req.sec_stab.len);
        cl->read_remaining = cur_op->req.sec_stab.len;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_READ)
    {
        if (cur_op->req.rw.len > 0)
            cur_op->buf = memalign(512, cur_op->req.rw.len);
        cl->read_remaining = 0;
    }
    else if (cur_op->req.hdr.opcode == OSD_OP_WRITE)
    {
        if (cur_op->req.rw.len > 0)
            cur_op->buf = memalign(512, cur_op->req.rw.len);
        cl->read_remaining = cur_op->req.rw.len;
    }
    if (cl->read_remaining > 0)
    {
        // Read data
        cl->read_buf = cur_op->buf;
        cl->read_state = CL_READ_DATA;
    }
    else
    {
        // Operation is ready
        cl->read_op = NULL;
        cl->read_state = 0;
        exec_op(cur_op);
    }
}

void osd_t::handle_reply_hdr(osd_client_t *cl)
{
    osd_op_t *cur_op = cl->read_op;
    auto req_it = cl->sent_ops.find(cur_op->req.hdr.id);
    if (req_it == cl->sent_ops.end())
    {
        // Command out of sync. Drop connection
        printf("Client %d command out of sync: id %lu\n", cl->peer_fd, cur_op->req.hdr.id);
        stop_client(cl->peer_fd);
        return;
    }
    osd_op_t *op = req_it->second;
    memcpy(op->reply.buf, cur_op->req.buf, OSD_PACKET_SIZE);
    if (op->reply.hdr.opcode == OSD_OP_SECONDARY_READ &&
        op->reply.hdr.retval > 0)
    {
        // Read data. In this case we assume that the buffer is preallocated by the caller (!)
        assert(op->buf);
        cl->read_state = CL_READ_REPLY_DATA;
        cl->read_reply_id = op->req.hdr.id;
        cl->read_buf = op->buf;
        cl->read_remaining = op->reply.hdr.retval;
    }
    else if (op->reply.hdr.opcode == OSD_OP_SECONDARY_LIST &&
        op->reply.hdr.retval > 0)
    {
        op->buf = memalign(512, sizeof(obj_ver_id) * op->reply.hdr.retval);
        cl->read_state = CL_READ_REPLY_DATA;
        cl->read_reply_id = op->req.hdr.id;
        cl->read_buf = op->buf;
        cl->read_remaining = sizeof(obj_ver_id) * op->reply.hdr.retval;
    }
    else
    {
        cl->read_state = 0;
        cl->sent_ops.erase(req_it);
        // Measure subop latency
        timeval tv_end;
        gettimeofday(&tv_end, NULL);
        subop_stat_count[op->req.hdr.opcode]++;
        subop_stat_sum[op->req.hdr.opcode] += (
            (tv_end.tv_sec - op->tv_begin.tv_sec)*1000000 +
            tv_end.tv_usec - op->tv_begin.tv_usec
        );
        op->callback(op);
    }
}