FreeBSD-5.3/sys/nfsclient/nfs_nfsiod.c
/*
* 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 <rpc/rpcclnt.h>
#include <nfs/xdr_subs.h>
#include <nfs/rpcv2.h>
#include <nfs/nfsproto.h>
#include <nfsclient/nfs.h>
#include <nfsclient/nfsm_subs.h>
#include <nfsclient/nfsmount.h>
#include <nfsclient/nfsnode.h>
#include <nfsclient/nfs_lock.h>
static MALLOC_DEFINE(M_NFSSVC, "NFS srvsock", "Nfs server structure");
static void nfssvc_iod(void *);
static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
SYSCTL_DECL(_vfs_nfs);
/* Maximum number of seconds a nfsiod kthread will sleep before exiting */
static unsigned int nfs_iodmaxidle = 120;
SYSCTL_UINT(_vfs_nfs, OID_AUTO, iodmaxidle, CTLFLAG_RW, &nfs_iodmaxidle, 0, "");
/* Maximum number of nfsiod kthreads */
unsigned int nfs_iodmax = 20;
/* Minimum number of nfsiod kthreads to keep as spares */
static unsigned int nfs_iodmin = 4;
static int
sysctl_iodmin(SYSCTL_HANDLER_ARGS)
{
int error, i;
int newmin;
newmin = nfs_iodmin;
error = sysctl_handle_int(oidp, &newmin, 0, req);
if (error || (req->newptr == NULL))
return (error);
if (newmin > nfs_iodmax)
return (EINVAL);
nfs_iodmin = newmin;
if (nfs_numasync >= nfs_iodmin)
return (0);
/*
* If the current number of nfsiod is lower
* than the new minimum, create some more.
*/
for (i = nfs_iodmin - nfs_numasync; i > 0; i--)
nfs_nfsiodnew();
return (0);
}
SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmin, CTLTYPE_UINT | CTLFLAG_RW, 0,
sizeof (nfs_iodmin), sysctl_iodmin, "IU", "");
static int
sysctl_iodmax(SYSCTL_HANDLER_ARGS)
{
int error, i;
int iod, newmax;
newmax = nfs_iodmax;
error = sysctl_handle_int(oidp, &newmax, 0, req);
if (error || (req->newptr == NULL))
return (error);
if (newmax > NFS_MAXASYNCDAEMON)
return (EINVAL);
nfs_iodmax = newmax;
if (nfs_numasync <= nfs_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 = nfs_numasync - 1;
for (i = 0; i < nfs_numasync - nfs_iodmax; i++) {
if (nfs_iodwant[iod])
wakeup(&nfs_iodwant[iod]);
iod--;
}
return (0);
}
SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
sizeof (nfs_iodmax), sysctl_iodmax, "IU", "");
int
nfs_nfsiodnew(void)
{
int error, i;
int newiod;
if (nfs_numasync >= nfs_iodmax)
return (-1);
newiod = -1;
for (i = 0; i < nfs_iodmax; i++)
if (nfs_asyncdaemon[i] == 0) {
nfs_asyncdaemon[i]++;
newiod = i;
break;
}
if (newiod == -1)
return (-1);
error = kthread_create(nfssvc_iod, nfs_asyncdaemon + i, NULL, RFHIGHPID,
0, "nfsiod %d", newiod);
if (error)
return (-1);
nfs_numasync++;
return (newiod);
}
static void
nfsiod_setup(void *dummy)
{
int i;
int error;
TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin);
/* Silently limit the start number of nfsiod's */
if (nfs_iodmin > NFS_MAXASYNCDAEMON)
nfs_iodmin = NFS_MAXASYNCDAEMON;
for (i = 0; i < nfs_iodmin; i++) {
error = nfs_nfsiodnew();
if (error == -1)
panic("nfsiod_setup: nfs_nfsiodnew failed");
}
}
SYSINIT(nfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
static int nfs_defect = 0;
SYSCTL_INT(_vfs_nfs, OID_AUTO, defect, CTLFLAG_RW, &nfs_defect, 0, "");
int
nfsclnt(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 : nfslockdans(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
nfssvc_iod(void *instance)
{
struct buf *bp;
struct nfsmount *nmp;
int myiod, timo;
int error = 0;
mtx_lock(&Giant);
myiod = (int *)instance - nfs_asyncdaemon;
/*
* Main loop
*/
for (;;) {
while (((nmp = nfs_iodmount[myiod]) == NULL
|| !TAILQ_FIRST(&nmp->nm_bufq))
&& error == 0) {
if (myiod >= nfs_iodmax)
goto finish;
if (nmp)
nmp->nm_bufqiods--;
nfs_iodwant[myiod] = curthread->td_proc;
nfs_iodmount[myiod] = NULL;
/*
* Always keep at least nfs_iodmin kthreads.
*/
timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz;
error = tsleep(&nfs_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 <= nfs_numasync) {
nmp->nm_bufqwant = 0;
wakeup(&nmp->nm_bufq);
}
if (bp->b_iocmd == BIO_READ)
(void) nfs_doio(bp, bp->b_rcred, NULL);
else
(void) nfs_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 (nfs_defect && nmp->nm_bufqiods > 1) {
NFS_DPF(ASYNCIO,
("nfssvc_iod: iod %d defecting from mount %p\n",
myiod, nmp));
nfs_iodmount[myiod] = NULL;
nmp->nm_bufqiods--;
break;
}
}
}
finish:
nfs_asyncdaemon[myiod] = 0;
if (nmp)
nmp->nm_bufqiods--;
nfs_iodwant[myiod] = NULL;
nfs_iodmount[myiod] = NULL;
/* Someone may be waiting for the last nfsiod to terminate. */
if (--nfs_numasync == 0)
wakeup(&nfs_numasync);
if ((error == 0) || (error == EWOULDBLOCK))
kthread_exit(0);
/* Abnormal termination */
kthread_exit(1);
}