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 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * @(#)nfs_syscalls.c 8.5 (Berkeley) 3/30/95
33 */
34
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD: releng/6.2/sys/nfsclient/nfs_nfsiod.c 159418 2006-06-08 22:57:07Z rwatson $");
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/sysproto.h>
41 #include <sys/kernel.h>
42 #include <sys/sysctl.h>
43 #include <sys/file.h>
44 #include <sys/filedesc.h>
45 #include <sys/vnode.h>
46 #include <sys/malloc.h>
47 #include <sys/mount.h>
48 #include <sys/proc.h>
49 #include <sys/bio.h>
50 #include <sys/buf.h>
51 #include <sys/mbuf.h>
52 #include <sys/socket.h>
53 #include <sys/socketvar.h>
54 #include <sys/domain.h>
55 #include <sys/protosw.h>
56 #include <sys/namei.h>
57 #include <sys/unistd.h>
58 #include <sys/kthread.h>
59 #include <sys/fcntl.h>
60 #include <sys/lockf.h>
61 #include <sys/mutex.h>
62
63 #include <netinet/in.h>
64 #include <netinet/tcp.h>
65
66 #include <rpc/rpcclnt.h>
67
68 #include <nfs/xdr_subs.h>
69 #include <nfs/rpcv2.h>
70 #include <nfs/nfsproto.h>
71 #include <nfsclient/nfs.h>
72 #include <nfsclient/nfsm_subs.h>
73 #include <nfsclient/nfsmount.h>
74 #include <nfsclient/nfsnode.h>
75 #include <nfsclient/nfs_lock.h>
76
77 static MALLOC_DEFINE(M_NFSSVC, "NFS srvsock", "Nfs server structure");
78
79 static void nfssvc_iod(void *);
80
81 static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
82
83 SYSCTL_DECL(_vfs_nfs);
84
85 /* Maximum number of seconds a nfsiod kthread will sleep before exiting */
86 static unsigned int nfs_iodmaxidle = 120;
87 SYSCTL_UINT(_vfs_nfs, OID_AUTO, iodmaxidle, CTLFLAG_RW, &nfs_iodmaxidle, 0, "");
88
89 /* Maximum number of nfsiod kthreads */
90 unsigned int nfs_iodmax = 20;
91
92 /* Minimum number of nfsiod kthreads to keep as spares */
93 static unsigned int nfs_iodmin = 0;
94
95 static int
96 sysctl_iodmin(SYSCTL_HANDLER_ARGS)
97 {
98 int error, i;
99 int newmin;
100
101 newmin = nfs_iodmin;
102 error = sysctl_handle_int(oidp, &newmin, 0, req);
103 if (error || (req->newptr == NULL))
104 return (error);
105 if (newmin > nfs_iodmax)
106 return (EINVAL);
107 nfs_iodmin = newmin;
108 if (nfs_numasync >= nfs_iodmin)
109 return (0);
110 /*
111 * If the current number of nfsiod is lower
112 * than the new minimum, create some more.
113 */
114 for (i = nfs_iodmin - nfs_numasync; i > 0; i--)
115 nfs_nfsiodnew();
116 return (0);
117 }
118 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmin, CTLTYPE_UINT | CTLFLAG_RW, 0,
119 sizeof (nfs_iodmin), sysctl_iodmin, "IU", "");
120
121
122 static int
123 sysctl_iodmax(SYSCTL_HANDLER_ARGS)
124 {
125 int error, i;
126 int iod, newmax;
127
128 newmax = nfs_iodmax;
129 error = sysctl_handle_int(oidp, &newmax, 0, req);
130 if (error || (req->newptr == NULL))
131 return (error);
132 if (newmax > NFS_MAXASYNCDAEMON)
133 return (EINVAL);
134 nfs_iodmax = newmax;
135 if (nfs_numasync <= nfs_iodmax)
136 return (0);
137 /*
138 * If there are some asleep nfsiods that should
139 * exit, wakeup() them so that they check nfs_iodmax
140 * and exit. Those who are active will exit as
141 * soon as they finish I/O.
142 */
143 iod = nfs_numasync - 1;
144 for (i = 0; i < nfs_numasync - nfs_iodmax; i++) {
145 if (nfs_iodwant[iod])
146 wakeup(&nfs_iodwant[iod]);
147 iod--;
148 }
149 return (0);
150 }
151 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
152 sizeof (nfs_iodmax), sysctl_iodmax, "IU", "");
153
154 int
155 nfs_nfsiodnew(void)
156 {
157 int error, i;
158 int newiod;
159
160 if (nfs_numasync >= nfs_iodmax)
161 return (-1);
162 newiod = -1;
163 for (i = 0; i < nfs_iodmax; i++)
164 if (nfs_asyncdaemon[i] == 0) {
165 nfs_asyncdaemon[i]++;
166 newiod = i;
167 break;
168 }
169 if (newiod == -1)
170 return (-1);
171 error = kthread_create(nfssvc_iod, nfs_asyncdaemon + i, NULL, RFHIGHPID,
172 0, "nfsiod %d", newiod);
173 if (error)
174 return (-1);
175 nfs_numasync++;
176 return (newiod);
177 }
178
179 static void
180 nfsiod_setup(void *dummy)
181 {
182 int i;
183 int error;
184
185 TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin);
186 /* Silently limit the start number of nfsiod's */
187 if (nfs_iodmin > NFS_MAXASYNCDAEMON)
188 nfs_iodmin = NFS_MAXASYNCDAEMON;
189
190 for (i = 0; i < nfs_iodmin; i++) {
191 error = nfs_nfsiodnew();
192 if (error == -1)
193 panic("nfsiod_setup: nfs_nfsiodnew failed");
194 }
195 }
196 SYSINIT(nfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
197
198 static int nfs_defect = 0;
199 SYSCTL_INT(_vfs_nfs, OID_AUTO, defect, CTLFLAG_RW, &nfs_defect, 0, "");
200
201 /*
202 * Asynchronous I/O daemons for client nfs.
203 * They do read-ahead and write-behind operations on the block I/O cache.
204 * Returns if we hit the timeout defined by the iodmaxidle sysctl.
205 */
206 static void
207 nfssvc_iod(void *instance)
208 {
209 struct buf *bp;
210 struct nfsmount *nmp;
211 int myiod, timo;
212 int error = 0;
213
214 mtx_lock(&Giant);
215 myiod = (int *)instance - nfs_asyncdaemon;
216 /*
217 * Main loop
218 */
219 for (;;) {
220 while (((nmp = nfs_iodmount[myiod]) == NULL
221 || !TAILQ_FIRST(&nmp->nm_bufq))
222 && error == 0) {
223 if (myiod >= nfs_iodmax)
224 goto finish;
225 if (nmp)
226 nmp->nm_bufqiods--;
227 nfs_iodwant[myiod] = curthread->td_proc;
228 nfs_iodmount[myiod] = NULL;
229 /*
230 * Always keep at least nfs_iodmin kthreads.
231 */
232 timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz;
233 error = tsleep(&nfs_iodwant[myiod], PWAIT | PCATCH,
234 "-", timo);
235 }
236 if (error)
237 break;
238 while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) {
239 /* Take one off the front of the list */
240 TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist);
241 nmp->nm_bufqlen--;
242 if (nmp->nm_bufqwant && nmp->nm_bufqlen <= nfs_numasync) {
243 nmp->nm_bufqwant = 0;
244 wakeup(&nmp->nm_bufq);
245 }
246 if (bp->b_flags & B_DIRECT) {
247 KASSERT((bp->b_iocmd == BIO_WRITE), ("nfscvs_iod: BIO_WRITE not set"));
248 (void)nfs_doio_directwrite(bp);
249 } else {
250 if (bp->b_iocmd == BIO_READ)
251 (void) nfs_doio(bp->b_vp, bp, bp->b_rcred, NULL);
252 else
253 (void) nfs_doio(bp->b_vp, bp, bp->b_wcred, NULL);
254 }
255
256 /*
257 * If there are more than one iod on this mount, then defect
258 * so that the iods can be shared out fairly between the mounts
259 */
260 if (nfs_defect && nmp->nm_bufqiods > 1) {
261 NFS_DPF(ASYNCIO,
262 ("nfssvc_iod: iod %d defecting from mount %p\n",
263 myiod, nmp));
264 nfs_iodmount[myiod] = NULL;
265 nmp->nm_bufqiods--;
266 break;
267 }
268 }
269 }
270 finish:
271 nfs_asyncdaemon[myiod] = 0;
272 if (nmp)
273 nmp->nm_bufqiods--;
274 nfs_iodwant[myiod] = NULL;
275 nfs_iodmount[myiod] = NULL;
276 /* Someone may be waiting for the last nfsiod to terminate. */
277 if (--nfs_numasync == 0)
278 wakeup(&nfs_numasync);
279 mtx_unlock(&Giant);
280 if ((error == 0) || (error == EWOULDBLOCK))
281 kthread_exit(0);
282 /* Abnormal termination */
283 kthread_exit(1);
284 }
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