nfs_nfsiod.c revision 89324 
1/*
2 * Copyright (c) 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Rick Macklem at The University of Guelph.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 *	@(#)nfs_syscalls.c	8.5 (Berkeley) 3/30/95
37 */
38
39#include <sys/cdefs.h>
40__FBSDID("$FreeBSD: head/sys/nfsclient/nfs_nfsiod.c 89324 2002-01-14 02:13:46Z peter $");
41
42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/sysproto.h>
45#include <sys/kernel.h>
46#include <sys/sysctl.h>
47#include <sys/file.h>
48#include <sys/filedesc.h>
49#include <sys/vnode.h>
50#include <sys/malloc.h>
51#include <sys/mount.h>
52#include <sys/proc.h>
53#include <sys/bio.h>
54#include <sys/buf.h>
55#include <sys/mbuf.h>
56#include <sys/socket.h>
57#include <sys/socketvar.h>
58#include <sys/domain.h>
59#include <sys/protosw.h>
60#include <sys/namei.h>
61#include <sys/unistd.h>
62#include <sys/kthread.h>
63#include <sys/fcntl.h>
64#include <sys/lockf.h>
65#include <sys/mutex.h>
66
67#include <netinet/in.h>
68#include <netinet/tcp.h>
69#include <nfs/xdr_subs.h>
70#include <nfs/rpcv2.h>
71#include <nfs/nfsproto.h>
72#include <nfsclient/nfs.h>
73#include <nfsclient/nfsm_subs.h>
74#include <nfsclient/nfsmount.h>
75#include <nfsclient/nfsnode.h>
76#include <nfsclient/nfs_lock.h>
77
78static MALLOC_DEFINE(M_NFSSVC, "NFS srvsock", "Nfs server structure");
79
80static void	nfssvc_iod(void *);
81
82static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
83
84SYSCTL_DECL(_vfs_nfs);
85
86/* Minimum number of nfsiod kthreads to keep as spares */
87static unsigned int nfs_iodmin = 4;
88SYSCTL_INT(_vfs_nfs, OID_AUTO, iodmin, CTLFLAG_RW, &nfs_iodmin, 0, "");
89
90/* Maximum number of seconds a nfsiod kthread will sleep before exiting */
91static int nfs_iodmaxidle = 120;
92SYSCTL_INT(_vfs_nfs, OID_AUTO, iodmaxidle, CTLFLAG_RW, &nfs_iodmaxidle, 0, "");
93
94int
95nfs_nfsiodnew(void)
96{
97	int error, i;
98	int newiod;
99
100	newiod = -1;
101	for (i = 0; i < NFS_MAXASYNCDAEMON; i++)
102		if (nfs_asyncdaemon[i] == 0) {
103			nfs_asyncdaemon[i]++;
104			newiod = i;
105			break;
106		}
107	if (newiod == -1)
108		return (-1);
109	error = kthread_create(nfssvc_iod, nfs_asyncdaemon + i, NULL, RFHIGHPID,
110	    "nfsiod %d", newiod);
111	if (error)
112		return (-1);
113	nfs_numasync++;
114	return (newiod);
115}
116
117static void
118nfsiod_setup(void *dummy)
119{
120	int i;
121	int error;
122
123	TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin);
124	/* Silently limit the start number of nfsiod's */
125	if (nfs_iodmin > NFS_MAXASYNCDAEMON)
126		nfs_iodmin = NFS_MAXASYNCDAEMON;
127
128	for (i = 0; i < nfs_iodmin; i++) {
129		error = nfs_nfsiodnew();
130		if (error == -1)
131			panic("nfsiod_setup: nfs_nfsiodnew failed");
132	}
133}
134SYSINIT(nfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
135
136static int nfs_defect = 0;
137SYSCTL_INT(_vfs_nfs, OID_AUTO, defect, CTLFLAG_RW, &nfs_defect, 0, "");
138
139int
140nfsclnt(struct thread *td, struct nfsclnt_args *uap)
141{
142	struct lockd_ans la;
143	int error;
144
145	if ((uap->flag & NFSCLNT_LOCKDANS) != 0) {
146		error = copyin(uap->argp, &la, sizeof(la));
147		return (error != 0 ? error : nfslockdans(td, &la));
148	}
149	return EINVAL;
150}
151
152/*
153 * Asynchronous I/O daemons for client nfs.
154 * They do read-ahead and write-behind operations on the block I/O cache.
155 * Returns if we hit the timeout defined by the iodmaxidle sysctl.
156 */
157static void
158nfssvc_iod(void *instance)
159{
160	struct buf *bp;
161	struct nfsmount *nmp;
162	int myiod, timo;
163	int error = 0;
164
165	mtx_lock(&Giant);
166	/*
167	 * Assign my position or return error if too many already running
168	 */
169	myiod = (int *)instance - nfs_asyncdaemon;
170	/*
171	 * Main loop
172	 */
173	for (;;) {
174	    while (((nmp = nfs_iodmount[myiod]) == NULL
175		   || !TAILQ_FIRST(&nmp->nm_bufq))
176		   && error == 0) {
177		if (nmp)
178			nmp->nm_bufqiods--;
179		nfs_iodwant[myiod] = curthread->td_proc;
180		nfs_iodmount[myiod] = NULL;
181		/*
182		 * Always keep at least nfs_iodmin kthreads.
183		 */
184		timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz;
185		error = tsleep((caddr_t)&nfs_iodwant[myiod], PWAIT | PCATCH,
186		    "nfsidl", timo);
187	    }
188	    if (error)
189		    break;
190	    while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) {
191		/* Take one off the front of the list */
192		TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist);
193		nmp->nm_bufqlen--;
194		if (nmp->nm_bufqwant && nmp->nm_bufqlen <= nfs_numasync) {
195		    nmp->nm_bufqwant = 0;
196		    wakeup(&nmp->nm_bufq);
197		}
198		if (bp->b_iocmd == BIO_READ)
199		    (void) nfs_doio(bp, bp->b_rcred, (struct thread *)0);
200		else
201		    (void) nfs_doio(bp, bp->b_wcred, (struct thread *)0);
202		/*
203		 * If there are more than one iod on this mount, then defect
204		 * so that the iods can be shared out fairly between the mounts
205		 */
206		if (nfs_defect && nmp->nm_bufqiods > 1) {
207		    NFS_DPF(ASYNCIO,
208			    ("nfssvc_iod: iod %d defecting from mount %p\n",
209			     myiod, nmp));
210		    nfs_iodmount[myiod] = NULL;
211		    nmp->nm_bufqiods--;
212		    break;
213		}
214	    }
215	}
216	nfs_asyncdaemon[myiod] = 0;
217	if (nmp)
218	    nmp->nm_bufqiods--;
219	nfs_iodwant[myiod] = NULL;
220	nfs_iodmount[myiod] = NULL;
221	nfs_numasync--;
222	if (error == EWOULDBLOCK)
223		kthread_exit(0);
224	/* Abnormal termination */
225	kthread_exit(1);
226}
227