/*
 * Copyright (c) 2009 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * 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.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
 * COPYRIGHT HOLDERS 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.
 */
/*
 * NFSIOD operations - now built into the kernel.
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/vnode.h>
#include <sys/fcntl.h>
#include <sys/protosw.h>
#include <sys/resourcevar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/socketops.h>
#include <sys/syslog.h>
#include <sys/thread.h>
#include <sys/tprintf.h>
#include <sys/sysctl.h>
#include <sys/signalvar.h>

#include <sys/signal2.h>

#include <netinet/in.h>
#include <netinet/tcp.h>

#include "rpcv2.h"
#include "nfsproto.h"
#include "nfs.h"
#include "xdr_subs.h"
#include "nfsm_subs.h"
#include "nfsmount.h"
#include "nfsnode.h"
#include "nfsrtt.h"

/*
 * nfs service connection reader thread
 */
void
nfssvc_iod_reader(void *arg)
{
        struct nfsmount *nmp = arg;
        struct nfsm_info *info;
        struct nfsreq *req;
        int error;

        lwkt_gettoken(&nmp->nm_token);

        if (nmp->nm_rxstate == NFSSVC_INIT)
                nmp->nm_rxstate = NFSSVC_PENDING;
        for (;;) {
                if (nmp->nm_rxstate == NFSSVC_WAITING) {
                        if (TAILQ_FIRST(&nmp->nm_reqq) == NULL &&
                            TAILQ_FIRST(&nmp->nm_reqrxq) == NULL) {
                                tsleep(&nmp->nm_rxstate, 0, "nfsidl", 0);
                        } else {
                                /*
                                 * This can happen during shutdown, we don't
                                 * want to hardloop.
                                 */
                                error = nfs_reply(nmp, NULL);
                                if (error && error != EWOULDBLOCK) {
                                        tsleep(&nmp->nm_rxstate, 0,
                                                "nfsxxx", hz / 10);
                                }
                        }
                        continue;
                }
                if (nmp->nm_rxstate != NFSSVC_PENDING)
                        break;
                nmp->nm_rxstate = NFSSVC_WAITING;

                /*
                 * Process requests which have received replies.  Only
                 * process the post-reply states.  If we get EINPROGRESS
                 * it means the request went back to an auth or retransmit
                 * state and we let the iod_writer thread deal with it.
                 *
                 * Any lock on the request is strictly temporary due to
                 * MP races (XXX).
                 *
                 * If the request completes we run the info->done call
                 * to finish up the I/O.
                 */
                while ((req = TAILQ_FIRST(&nmp->nm_reqrxq)) != NULL) {
                        if (req->r_flags & R_LOCKED) {
                                while (req->r_flags & R_LOCKED) {
                                        req->r_flags |= R_WANTED;
                                        tsleep(req, 0, "nfstrac", 0);
                                }
                                continue;
                        }
                        TAILQ_REMOVE(&nmp->nm_reqrxq, req, r_chain);
                        info = req->r_info;
                        KKASSERT(info);
                        info->error = nfs_request(info,
                                                  NFSM_STATE_PROCESSREPLY,
                                                  NFSM_STATE_DONE);
                        if (info->error == EINPROGRESS) {
                                kprintf("rxq: move info %p back to txq\n", info);
                                TAILQ_INSERT_TAIL(&nmp->nm_reqtxq, req, r_chain);
                                nfssvc_iod_writer_wakeup(nmp);
                        } else {
                                atomic_subtract_int(&nmp->nm_bioqlen, 1);
                                info->done(info);
                        }
                }
        }
        nmp->nm_rxthread = NULL;
        nmp->nm_rxstate = NFSSVC_DONE;

        lwkt_reltoken(&nmp->nm_token);
        wakeup(&nmp->nm_rxthread);
}

/*
 * nfs service connection writer thread
 *
 * The writer sits on the send side of the client's socket and
 * does both the initial processing of BIOs and also transmission
 * and retransmission of nfsreq's.
 *
 * The writer processes both new BIOs from nm_bioq and retransmit
 * or state machine jumpbacks from nm_reqtxq
 */
void
nfssvc_iod_writer(void *arg)
{
        struct nfsmount *nmp = arg;
        struct bio *bio;
        struct nfsreq *req;
        struct vnode *vp;
        nfsm_info_t info;

        lwkt_gettoken(&nmp->nm_token);

        if (nmp->nm_txstate == NFSSVC_INIT)
                nmp->nm_txstate = NFSSVC_PENDING;

        for (;;) {
                if (nmp->nm_txstate == NFSSVC_WAITING) {
                        tsleep(&nmp->nm_txstate, 0, "nfsidl", 0);
                        continue;
                }
                if (nmp->nm_txstate != NFSSVC_PENDING)
                        break;
                nmp->nm_txstate = NFSSVC_WAITING;

                /*
                 * Eep, we could blow out the mbuf allocator if we just
                 * did everything the kernel wanted us to do.
                 */
                while ((bio = TAILQ_FIRST(&nmp->nm_bioq)) != NULL) {
                        if (nmp->nm_reqqlen > nfs_maxasyncbio)
                                break;
                        TAILQ_REMOVE(&nmp->nm_bioq, bio, bio_act);
                        vp = bio->bio_driver_info;
                        nfs_startio(vp, bio, NULL);
                }

                /*
                 * Process reauths & retransmits.  If we get an EINPROGRESS
                 * it means the state transitioned to WAITREPLY or later.
                 * Otherwise the request completed (probably with an error
                 * since we didn't get to a replied state).
                 */
                while ((req = TAILQ_FIRST(&nmp->nm_reqtxq)) != NULL) {
                        TAILQ_REMOVE(&nmp->nm_reqtxq, req, r_chain);
                        info = req->r_info;
                        KKASSERT(info);
                        info->error = nfs_request(info,
                                                  NFSM_STATE_AUTH,
                                                  NFSM_STATE_WAITREPLY);
                        if (info->error == EINPROGRESS) {
                                ;
                        } else {
                                atomic_subtract_int(&nmp->nm_bioqlen, 1);
                                info->done(info);
                        }
                }
        }
        nmp->nm_txthread = NULL;
        nmp->nm_txstate = NFSSVC_DONE;
        lwkt_reltoken(&nmp->nm_token);
        wakeup(&nmp->nm_txthread);
}

void
nfssvc_iod_stop1(struct nfsmount *nmp)
{
        nmp->nm_txstate = NFSSVC_STOPPING;
        nmp->nm_rxstate = NFSSVC_STOPPING;
}

void
nfssvc_iod_stop2(struct nfsmount *nmp)
{
        wakeup(&nmp->nm_txstate);
        while (nmp->nm_txthread)
                tsleep(&nmp->nm_txthread, 0, "nfssttx", hz*2);
        wakeup(&nmp->nm_rxstate);
        while (nmp->nm_rxthread)
                tsleep(&nmp->nm_rxthread, 0, "nfsstrx", hz*2);
}

void
nfssvc_iod_writer_wakeup(struct nfsmount *nmp)
{
        if (nmp->nm_txstate == NFSSVC_WAITING) {
                nmp->nm_txstate = NFSSVC_PENDING;
                wakeup(&nmp->nm_txstate);
        }
}

void
nfssvc_iod_reader_wakeup(struct nfsmount *nmp)
{
        if (nmp->nm_rxstate == NFSSVC_WAITING) {
                nmp->nm_rxstate = NFSSVC_PENDING;
                wakeup(&nmp->nm_rxstate);
        }
}