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/7.3/sys/nfsclient/nfs_nfsiod.c 172324 2007-09-25 21:08:49Z mohans $");
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, "nfsclient_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 mtx_lock(&nfs_iod_mtx);
106 if (newmin > nfs_iodmax) {
107 error = EINVAL;
108 goto out;
109 }
110 nfs_iodmin = newmin;
111 if (nfs_numasync >= nfs_iodmin)
112 goto out;
113 /*
114 * If the current number of nfsiod is lower
115 * than the new minimum, create some more.
116 */
117 for (i = nfs_iodmin - nfs_numasync; i > 0; i--)
118 nfs_nfsiodnew();
119 out:
120 mtx_unlock(&nfs_iod_mtx);
121 return (0);
122 }
123 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmin, CTLTYPE_UINT | CTLFLAG_RW, 0,
124 sizeof (nfs_iodmin), sysctl_iodmin, "IU", "");
125
126
127 static int
128 sysctl_iodmax(SYSCTL_HANDLER_ARGS)
129 {
130 int error, i;
131 int iod, newmax;
132
133 newmax = nfs_iodmax;
134 error = sysctl_handle_int(oidp, &newmax, 0, req);
135 if (error || (req->newptr == NULL))
136 return (error);
137 if (newmax > NFS_MAXASYNCDAEMON)
138 return (EINVAL);
139 mtx_lock(&nfs_iod_mtx);
140 nfs_iodmax = newmax;
141 if (nfs_numasync <= nfs_iodmax)
142 goto out;
143 /*
144 * If there are some asleep nfsiods that should
145 * exit, wakeup() them so that they check nfs_iodmax
146 * and exit. Those who are active will exit as
147 * soon as they finish I/O.
148 */
149 iod = nfs_numasync - 1;
150 for (i = 0; i < nfs_numasync - nfs_iodmax; i++) {
151 if (nfs_iodwant[iod])
152 wakeup(&nfs_iodwant[iod]);
153 iod--;
154 }
155 out:
156 mtx_unlock(&nfs_iod_mtx);
157 return (0);
158 }
159 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
160 sizeof (nfs_iodmax), sysctl_iodmax, "IU", "");
161
162 int
163 nfs_nfsiodnew(void)
164 {
165 int error, i;
166 int newiod;
167
168 if (nfs_numasync >= nfs_iodmax)
169 return (-1);
170 newiod = -1;
171 for (i = 0; i < nfs_iodmax; i++)
172 if (nfs_asyncdaemon[i] == 0) {
173 nfs_asyncdaemon[i]++;
174 newiod = i;
175 break;
176 }
177 if (newiod == -1)
178 return (-1);
179 mtx_unlock(&nfs_iod_mtx);
180 error = kthread_create(nfssvc_iod, nfs_asyncdaemon + i, NULL, RFHIGHPID,
181 0, "nfsiod %d", newiod);
182 mtx_lock(&nfs_iod_mtx);
183 if (error)
184 return (-1);
185 nfs_numasync++;
186 return (newiod);
187 }
188
189 static void
190 nfsiod_setup(void *dummy)
191 {
192 int i;
193 int error;
194
195 TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin);
196 mtx_lock(&nfs_iod_mtx);
197 /* Silently limit the start number of nfsiod's */
198 if (nfs_iodmin > NFS_MAXASYNCDAEMON)
199 nfs_iodmin = NFS_MAXASYNCDAEMON;
200
201 for (i = 0; i < nfs_iodmin; i++) {
202 error = nfs_nfsiodnew();
203 if (error == -1)
204 panic("nfsiod_setup: nfs_nfsiodnew failed");
205 }
206 mtx_unlock(&nfs_iod_mtx);
207 }
208 SYSINIT(nfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
209
210 static int nfs_defect = 0;
211 SYSCTL_INT(_vfs_nfs, OID_AUTO, defect, CTLFLAG_RW, &nfs_defect, 0, "");
212
213 /*
214 * Asynchronous I/O daemons for client nfs.
215 * They do read-ahead and write-behind operations on the block I/O cache.
216 * Returns if we hit the timeout defined by the iodmaxidle sysctl.
217 */
218 static void
219 nfssvc_iod(void *instance)
220 {
221 struct buf *bp;
222 struct nfsmount *nmp;
223 int myiod, timo;
224 int error = 0;
225
226 mtx_lock(&nfs_iod_mtx);
227 myiod = (int *)instance - nfs_asyncdaemon;
228 /*
229 * Main loop
230 */
231 for (;;) {
232 while (((nmp = nfs_iodmount[myiod]) == NULL)
233 || !TAILQ_FIRST(&nmp->nm_bufq)) {
234 if (myiod >= nfs_iodmax)
235 goto finish;
236 if (nmp)
237 nmp->nm_bufqiods--;
238 nfs_iodwant[myiod] = curthread->td_proc;
239 nfs_iodmount[myiod] = NULL;
240 /*
241 * Always keep at least nfs_iodmin kthreads.
242 */
243 timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz;
244 error = msleep(&nfs_iodwant[myiod], &nfs_iod_mtx, PWAIT | PCATCH,
245 "-", timo);
246 if (error) {
247 nmp = nfs_iodmount[myiod];
248 /*
249 * Rechecking the nm_bufq closes a rare race where the
250 * nfsiod is woken up at the exact time the idle timeout
251 * fires
252 */
253 if (nmp && TAILQ_FIRST(&nmp->nm_bufq))
254 error = 0;
255 break;
256 }
257 }
258 if (error)
259 break;
260 while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) {
261 int giant_locked = 0;
262
263 /* Take one off the front of the list */
264 TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist);
265 nmp->nm_bufqlen--;
266 if (nmp->nm_bufqwant && nmp->nm_bufqlen <= nfs_numasync) {
267 nmp->nm_bufqwant = 0;
268 wakeup(&nmp->nm_bufq);
269 }
270 mtx_unlock(&nfs_iod_mtx);
271 if (NFS_ISV4(bp->b_vp)) {
272 giant_locked = 1;
273 mtx_lock(&Giant);
274 }
275 if (bp->b_flags & B_DIRECT) {
276 KASSERT((bp->b_iocmd == BIO_WRITE), ("nfscvs_iod: BIO_WRITE not set"));
277 (void)nfs_doio_directwrite(bp);
278 } else {
279 if (bp->b_iocmd == BIO_READ)
280 (void) nfs_doio(bp->b_vp, bp, bp->b_rcred, NULL);
281 else
282 (void) nfs_doio(bp->b_vp, bp, bp->b_wcred, NULL);
283 }
284 if (giant_locked)
285 mtx_unlock(&Giant);
286 mtx_lock(&nfs_iod_mtx);
287 /*
288 * If there are more than one iod on this mount, then defect
289 * so that the iods can be shared out fairly between the mounts
290 */
291 if (nfs_defect && nmp->nm_bufqiods > 1) {
292 NFS_DPF(ASYNCIO,
293 ("nfssvc_iod: iod %d defecting from mount %p\n",
294 myiod, nmp));
295 nfs_iodmount[myiod] = NULL;
296 nmp->nm_bufqiods--;
297 break;
298 }
299 }
300 }
301 finish:
302 nfs_asyncdaemon[myiod] = 0;
303 if (nmp)
304 nmp->nm_bufqiods--;
305 nfs_iodwant[myiod] = NULL;
306 nfs_iodmount[myiod] = NULL;
307 /* Someone may be waiting for the last nfsiod to terminate. */
308 if (--nfs_numasync == 0)
309 wakeup(&nfs_numasync);
310 mtx_unlock(&nfs_iod_mtx);
311 if ((error == 0) || (error == EWOULDBLOCK))
312 kthread_exit(0);
313 /* Abnormal termination */
314 kthread_exit(1);
315 }
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