/*
 * Copyright (c) 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Rick Macklem at The University of Guelph.
 *
 * 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.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 *	@(#)nfs_syscalls.c	8.5 (Berkeley) 3/30/95
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/nfsclient/nfs_nfsiod.c,v 1.81 2004/04/11 13:30:20 peadar Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/namei.h>
#include <sys/unistd.h>
#include <sys/kthread.h>
#include <sys/fcntl.h>
#include <sys/lockf.h>
#include <sys/mutex.h>

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

#include <rpcx/rpcclnt.h>

#include <nfsx/xdr_subs.h>
#include <nfsx/rpcv2.h>
#include <nfsx/nfsproto.h>

#include <nfsxclient/nfs.h>
#include <nfsxclient/nfsm_subs.h>
#include <nfsxclient/nfsmount.h>
#include <nfsxclient/nfsnode.h>
#include <nfsxclient/nfs_lock.h>

static MALLOC_DEFINE(M_NFSSVC, "NFS srvsock", "Nfs server structure");

static void	nfsxsvc_iod(void *);

static int nfsx_asyncdaemon[NFS_MAXASYNCDAEMON];

SYSCTL_DECL(_vfs_nfsx);

/* Maximum number of seconds a nfsiod kthread will sleep before exiting */
static unsigned int nfsx_iodmaxidle = 120;
SYSCTL_UINT(_vfs_nfsx, OID_AUTO, iodmaxidle, CTLFLAG_RW, &nfsx_iodmaxidle, 0, "");

/* Maximum number of nfsiod kthreads */
unsigned int nfsx_iodmax = 20;

/* Minimum number of nfsiod kthreads to keep as spares */
static unsigned int nfsx_iodmin = 4;

static int
sysctl_iodmin(SYSCTL_HANDLER_ARGS)
{
	int error, i;
	int newmin;

	newmin = nfsx_iodmin;
	error = sysctl_handle_int(oidp, &newmin, 0, req);
	if (error || (req->newptr == NULL))
		return (error);
	if (newmin > nfsx_iodmax)
		return (EINVAL);
	nfsx_iodmin = newmin;
	if (nfsx_numasync >= nfsx_iodmin)
		return (0);
	/*
	 * If the current number of nfsiod is lower
	 * than the new minimum, create some more.
	 */
	for (i = nfsx_iodmin - nfsx_numasync; i > 0; i--)
		nfsx_nfsiodnew();
	return (0);
}

SYSCTL_PROC(_vfs_nfsx, OID_AUTO, iodmin, CTLTYPE_UINT | CTLFLAG_RW, 0,
    sizeof (nfsx_iodmin), sysctl_iodmin, "IU", "");

static int
sysctl_iodmax(SYSCTL_HANDLER_ARGS)
{
	int error, i;
	int iod, newmax;

	newmax = nfsx_iodmax;
	error = sysctl_handle_int(oidp, &newmax, 0, req);
	if (error || (req->newptr == NULL))
		return (error);
	if (newmax > NFS_MAXASYNCDAEMON)
		return (EINVAL);
	nfsx_iodmax = newmax;
	if (nfsx_numasync <= nfsx_iodmax)
		return (0);
	/*
	 * If there are some asleep nfsiods that should
	 * exit, wakeup() them so that they check nfs_iodmax
	 * and exit.  Those who are active will exit as
	 * soon as they finish I/O.
	 */
	iod = nfsx_numasync - 1;
	for (i = 0; i < nfsx_numasync - nfsx_iodmax; i++) {
		if (nfsx_iodwant[iod])
			wakeup(&nfsx_iodwant[iod]);
		iod--;
	}
	return (0);
}
SYSCTL_PROC(_vfs_nfsx, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
    sizeof (nfsx_iodmax), sysctl_iodmax, "IU", "");

int
nfsx_nfsiodnew(void)
{
	int error, i;
	int newiod;

	if (nfsx_numasync >= nfsx_iodmax)
		return (-1);
	newiod = -1;
	for (i = 0; i < nfsx_iodmax; i++)
		if (nfsx_asyncdaemon[i] == 0) {
			nfsx_asyncdaemon[i]++;
			newiod = i;
			break;
		}
	if (newiod == -1)
		return (-1);
	error = kthread_create(nfsxsvc_iod, nfsx_asyncdaemon + i, NULL,
	    RFHIGHPID, 0, "nfsxiod %d", newiod);
	if (error)
		return (-1);
	nfsx_numasync++;
	return (newiod);
}

static void
nfsiod_setup(void *dummy)
{
	int i;
	int error;

	TUNABLE_INT_FETCH("vfs.nfsx.iodmin", &nfsx_iodmin);
	/* Silently limit the start number of nfsiod's */
	if (nfsx_iodmin > NFS_MAXASYNCDAEMON)
		nfsx_iodmin = NFS_MAXASYNCDAEMON;

	for (i = 0; i < nfsx_iodmin; i++) {
		error = nfsx_nfsiodnew();
		if (error == -1)
			panic("nfsiod_setup: nfsx_nfsiodnew failed");
	}
}
SYSINIT(nfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);

static int nfsx_defect = 0;
SYSCTL_INT(_vfs_nfsx, OID_AUTO, defect, CTLFLAG_RW, &nfsx_defect, 0, "");

int nfsxclnt(struct thread *, struct nfsclnt_args *);

int
nfsxclnt(struct thread *td, struct nfsclnt_args *uap)
{
	struct lockd_ans la;
	int error;

	if ((uap->flag & NFSCLNT_LOCKDANS) != 0) {
		error = copyin(uap->argp, &la, sizeof(la));
		return (error != 0 ? error : nfsxlockdans(td, &la));
	}
	return EINVAL;
}

/*
 * Asynchronous I/O daemons for client nfs.
 * They do read-ahead and write-behind operations on the block I/O cache.
 * Returns if we hit the timeout defined by the iodmaxidle sysctl.
 */
static void
nfsxsvc_iod(void *instance)
{
	struct buf *bp;
	struct nfsmount *nmp;
	int myiod, timo;
	int error = 0;

	mtx_lock(&Giant);
	myiod = (int *)instance - nfsx_asyncdaemon;
	/*
	 * Main loop
	 */
	for (;;) {
	    while (((nmp = nfsx_iodmount[myiod]) == NULL
		   || !TAILQ_FIRST(&nmp->nm_bufq))
		   && error == 0) {
		if (myiod >= nfsx_iodmax)
			goto finish;
		if (nmp)
			nmp->nm_bufqiods--;
		nfsx_iodwant[myiod] = curthread->td_proc;
		nfsx_iodmount[myiod] = NULL;
		/*
		 * Always keep at least nfsx_iodmin kthreads.
		 */
		timo = (myiod < nfsx_iodmin) ? 0 : nfsx_iodmaxidle * hz;
		error = tsleep(&nfsx_iodwant[myiod], PWAIT | PCATCH,
		    "-", timo);
	    }
	    if (error)
		    break;
	    while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) {
		/* Take one off the front of the list */
		TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist);
		nmp->nm_bufqlen--;
		if (nmp->nm_bufqwant && nmp->nm_bufqlen <= nfsx_numasync) {
		    nmp->nm_bufqwant = 0;
		    wakeup(&nmp->nm_bufq);
		}
		if (bp->b_iocmd == BIO_READ)
			(void) nfsx_doio(bp, bp->b_rcred, NULL);
		else
			(void) nfsx_doio(bp, bp->b_wcred, NULL);
		/*
		 * If there are more than one iod on this mount, then defect
		 * so that the iods can be shared out fairly between the mounts
		 */
		if (nfsx_defect && nmp->nm_bufqiods > 1) {
		    NFS_DPF(ASYNCIO,
			    ("nfsxsvc_iod: iod %d defecting from mount %p\n",
			     myiod, nmp));
		    nfsx_iodmount[myiod] = NULL;
		    nmp->nm_bufqiods--;
		    break;
		}
	    }
	}
finish:
	nfsx_asyncdaemon[myiod] = 0;
	if (nmp)
	    nmp->nm_bufqiods--;
	nfsx_iodwant[myiod] = NULL;
	nfsx_iodmount[myiod] = NULL;
	/* Someone may be waiting for the last nfsiod to terminate. */
	if (--nfsx_numasync == 0)
		wakeup(&nfsx_numasync);
	if ((error == 0) || (error == EWOULDBLOCK))
		kthread_exit(0);
	/* Abnormal termination */
	kthread_exit(1);
}