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/9.2/sys/nfsclient/nfs_nfsiod.c 250258 2013-05-04 22:05:43Z rmacklem $");
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 #include <sys/taskqueue.h>
63
64 #include <netinet/in.h>
65 #include <netinet/tcp.h>
66
67 #include <nfs/xdr_subs.h>
68 #include <nfs/nfsproto.h>
69 #include <nfsclient/nfs.h>
70 #include <nfsclient/nfsm_subs.h>
71 #include <nfsclient/nfsmount.h>
72 #include <nfsclient/nfsnode.h>
73 #include <nfs/nfs_lock.h>
74
75 static MALLOC_DEFINE(M_NFSSVC, "nfsclient_srvsock", "Nfs server structure");
76
77 static void nfssvc_iod(void *);
78
79 static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
80
81 SYSCTL_DECL(_vfs_oldnfs);
82
83 /* Maximum number of seconds a nfsiod kthread will sleep before exiting */
84 static unsigned int nfs_iodmaxidle = 120;
85 SYSCTL_UINT(_vfs_oldnfs, OID_AUTO, iodmaxidle, CTLFLAG_RW, &nfs_iodmaxidle, 0,
86 "Max number of seconds an nfsiod kthread will sleep before exiting");
87
88 /* Maximum number of nfsiod kthreads */
89 unsigned int nfs_iodmax = 20;
90
91 /* Minimum number of nfsiod kthreads to keep as spares */
92 static unsigned int nfs_iodmin = 0;
93
94 static int nfs_nfsiodnew_sync(void);
95
96 static int
97 sysctl_iodmin(SYSCTL_HANDLER_ARGS)
98 {
99 int error, i;
100 int newmin;
101
102 newmin = nfs_iodmin;
103 error = sysctl_handle_int(oidp, &newmin, 0, req);
104 if (error || (req->newptr == NULL))
105 return (error);
106 mtx_lock(&nfs_iod_mtx);
107 if (newmin > nfs_iodmax) {
108 error = EINVAL;
109 goto out;
110 }
111 nfs_iodmin = newmin;
112 if (nfs_numasync >= nfs_iodmin)
113 goto out;
114 /*
115 * If the current number of nfsiod is lower
116 * than the new minimum, create some more.
117 */
118 for (i = nfs_iodmin - nfs_numasync; i > 0; i--)
119 nfs_nfsiodnew_sync();
120 out:
121 mtx_unlock(&nfs_iod_mtx);
122 return (0);
123 }
124 SYSCTL_PROC(_vfs_oldnfs, OID_AUTO, iodmin, CTLTYPE_UINT | CTLFLAG_RW, 0,
125 sizeof (nfs_iodmin), sysctl_iodmin, "IU",
126 "Min number of nfsiod kthreads to keep as spares");
127
128
129 static int
130 sysctl_iodmax(SYSCTL_HANDLER_ARGS)
131 {
132 int error, i;
133 int iod, newmax;
134
135 newmax = nfs_iodmax;
136 error = sysctl_handle_int(oidp, &newmax, 0, req);
137 if (error || (req->newptr == NULL))
138 return (error);
139 if (newmax > NFS_MAXASYNCDAEMON)
140 return (EINVAL);
141 mtx_lock(&nfs_iod_mtx);
142 nfs_iodmax = newmax;
143 if (nfs_numasync <= nfs_iodmax)
144 goto out;
145 /*
146 * If there are some asleep nfsiods that should
147 * exit, wakeup() them so that they check nfs_iodmax
148 * and exit. Those who are active will exit as
149 * soon as they finish I/O.
150 */
151 iod = nfs_numasync - 1;
152 for (i = 0; i < nfs_numasync - nfs_iodmax; i++) {
153 if (nfs_iodwant[iod] == NFSIOD_AVAILABLE)
154 wakeup(&nfs_iodwant[iod]);
155 iod--;
156 }
157 out:
158 mtx_unlock(&nfs_iod_mtx);
159 return (0);
160 }
161 SYSCTL_PROC(_vfs_oldnfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
162 sizeof (nfs_iodmax), sysctl_iodmax, "IU",
163 "Max number of nfsiod kthreads");
164
165 static int
166 nfs_nfsiodnew_sync(void)
167 {
168 int error, i;
169
170 mtx_assert(&nfs_iod_mtx, MA_OWNED);
171 for (i = 0; i < nfs_iodmax; i++) {
172 if (nfs_asyncdaemon[i] == 0) {
173 nfs_asyncdaemon[i] = 1;
174 break;
175 }
176 }
177 if (i == nfs_iodmax)
178 return (0);
179 mtx_unlock(&nfs_iod_mtx);
180 error = kproc_create(nfssvc_iod, nfs_asyncdaemon + i, NULL,
181 RFHIGHPID, 0, "nfsiod %d", i);
182 mtx_lock(&nfs_iod_mtx);
183 if (error == 0) {
184 nfs_numasync++;
185 nfs_iodwant[i] = NFSIOD_AVAILABLE;
186 } else
187 nfs_asyncdaemon[i] = 0;
188 return (error);
189 }
190
191 void
192 nfs_nfsiodnew_tq(__unused void *arg, int pending)
193 {
194
195 mtx_lock(&nfs_iod_mtx);
196 while (pending > 0) {
197 pending--;
198 nfs_nfsiodnew_sync();
199 }
200 mtx_unlock(&nfs_iod_mtx);
201 }
202
203 void
204 nfs_nfsiodnew(void)
205 {
206
207 mtx_assert(&nfs_iod_mtx, MA_OWNED);
208 taskqueue_enqueue(taskqueue_thread, &nfs_nfsiodnew_task);
209 }
210
211 static void
212 nfsiod_setup(void *dummy)
213 {
214 int error;
215
216 TUNABLE_INT_FETCH("vfs.oldnfs.iodmin", &nfs_iodmin);
217 mtx_lock(&nfs_iod_mtx);
218 /* Silently limit the start number of nfsiod's */
219 if (nfs_iodmin > NFS_MAXASYNCDAEMON)
220 nfs_iodmin = NFS_MAXASYNCDAEMON;
221
222 while (nfs_numasync < nfs_iodmin) {
223 error = nfs_nfsiodnew_sync();
224 if (error == -1)
225 panic("nfsiod_setup: nfs_nfsiodnew failed");
226 }
227 mtx_unlock(&nfs_iod_mtx);
228 }
229 SYSINIT(nfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
230
231 static int nfs_defect = 0;
232 SYSCTL_INT(_vfs_oldnfs, OID_AUTO, defect, CTLFLAG_RW, &nfs_defect, 0,
233 "Allow nfsiods to migrate serving different mounts");
234
235 /*
236 * Asynchronous I/O daemons for client nfs.
237 * They do read-ahead and write-behind operations on the block I/O cache.
238 * Returns if we hit the timeout defined by the iodmaxidle sysctl.
239 */
240 static void
241 nfssvc_iod(void *instance)
242 {
243 struct buf *bp;
244 struct nfsmount *nmp;
245 int myiod, timo;
246 int error = 0;
247
248 mtx_lock(&nfs_iod_mtx);
249 myiod = (int *)instance - nfs_asyncdaemon;
250 /*
251 * Main loop
252 */
253 for (;;) {
254 while (((nmp = nfs_iodmount[myiod]) == NULL)
255 || !TAILQ_FIRST(&nmp->nm_bufq)) {
256 if (myiod >= nfs_iodmax)
257 goto finish;
258 if (nmp)
259 nmp->nm_bufqiods--;
260 if (nfs_iodwant[myiod] == NFSIOD_NOT_AVAILABLE)
261 nfs_iodwant[myiod] = NFSIOD_AVAILABLE;
262 nfs_iodmount[myiod] = NULL;
263 /*
264 * Always keep at least nfs_iodmin kthreads.
265 */
266 timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz;
267 error = msleep(&nfs_iodwant[myiod], &nfs_iod_mtx, PWAIT | PCATCH,
268 "-", timo);
269 if (error) {
270 nmp = nfs_iodmount[myiod];
271 /*
272 * Rechecking the nm_bufq closes a rare race where the
273 * nfsiod is woken up at the exact time the idle timeout
274 * fires
275 */
276 if (nmp && TAILQ_FIRST(&nmp->nm_bufq))
277 error = 0;
278 break;
279 }
280 }
281 if (error)
282 break;
283 while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) {
284 int giant_locked = 0;
285
286 /* Take one off the front of the list */
287 TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist);
288 nmp->nm_bufqlen--;
289 if (nmp->nm_bufqwant && nmp->nm_bufqlen <= nfs_numasync) {
290 nmp->nm_bufqwant = 0;
291 wakeup(&nmp->nm_bufq);
292 }
293 mtx_unlock(&nfs_iod_mtx);
294 if (NFS_ISV4(bp->b_vp)) {
295 giant_locked = 1;
296 mtx_lock(&Giant);
297 }
298 if (bp->b_flags & B_DIRECT) {
299 KASSERT((bp->b_iocmd == BIO_WRITE), ("nfscvs_iod: BIO_WRITE not set"));
300 (void)nfs_doio_directwrite(bp);
301 } else {
302 if (bp->b_iocmd == BIO_READ)
303 (void) nfs_doio(bp->b_vp, bp, bp->b_rcred, NULL);
304 else
305 (void) nfs_doio(bp->b_vp, bp, bp->b_wcred, NULL);
306 }
307 if (giant_locked)
308 mtx_unlock(&Giant);
309 mtx_lock(&nfs_iod_mtx);
310 /*
311 * Make sure the nmp hasn't been dismounted as soon as
312 * nfs_doio() completes for the last buffer.
313 */
314 nmp = nfs_iodmount[myiod];
315 if (nmp == NULL)
316 break;
317
318 /*
319 * If there are more than one iod on this mount, then defect
320 * so that the iods can be shared out fairly between the mounts
321 */
322 if (nfs_defect && nmp->nm_bufqiods > 1) {
323 NFS_DPF(ASYNCIO,
324 ("nfssvc_iod: iod %d defecting from mount %p\n",
325 myiod, nmp));
326 nfs_iodmount[myiod] = NULL;
327 nmp->nm_bufqiods--;
328 break;
329 }
330 }
331 }
332 finish:
333 nfs_asyncdaemon[myiod] = 0;
334 if (nmp)
335 nmp->nm_bufqiods--;
336 nfs_iodwant[myiod] = NFSIOD_NOT_AVAILABLE;
337 nfs_iodmount[myiod] = NULL;
338 /* Someone may be waiting for the last nfsiod to terminate. */
339 if (--nfs_numasync == 0)
340 wakeup(&nfs_numasync);
341 mtx_unlock(&nfs_iod_mtx);
342 if ((error == 0) || (error == EWOULDBLOCK))
343 kproc_exit(0);
344 /* Abnormal termination */
345 kproc_exit(1);
346 }
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