1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Rick Macklem at The University of Guelph.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * from nfs_syscalls.c 8.5 (Berkeley) 3/30/95
35 */
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/sysproto.h>
40 #include <sys/kernel.h>
41 #include <sys/sysctl.h>
42 #include <sys/file.h>
43 #include <sys/vnode.h>
44 #include <sys/malloc.h>
45 #include <sys/mount.h>
46 #include <sys/proc.h>
47 #include <sys/bio.h>
48 #include <sys/buf.h>
49 #include <sys/mbuf.h>
50 #include <sys/socket.h>
51 #include <sys/socketvar.h>
52 #include <sys/domain.h>
53 #include <sys/protosw.h>
54 #include <sys/namei.h>
55 #include <sys/unistd.h>
56 #include <sys/kthread.h>
57 #include <sys/fcntl.h>
58 #include <sys/lockf.h>
59 #include <sys/mutex.h>
60 #include <sys/taskqueue.h>
61
62 #include <netinet/in.h>
63 #include <netinet/tcp.h>
64
65 #include <fs/nfs/nfsport.h>
66 #include <fs/nfsclient/nfsmount.h>
67 #include <fs/nfsclient/nfs.h>
68 #include <fs/nfsclient/nfsnode.h>
69
70 extern struct mtx ncl_iod_mutex;
71 extern struct task ncl_nfsiodnew_task;
72
73 int ncl_numasync;
74 enum nfsiod_state ncl_iodwant[NFS_MAXASYNCDAEMON];
75 struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON];
76
77 static void nfssvc_iod(void *);
78
79 static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
80
81 SYSCTL_DECL(_vfs_nfs);
82
83 /* Maximum number of seconds a nfsiod kthread will sleep before exiting */
84 static unsigned int nfs_iodmaxidle = 120;
85 SYSCTL_UINT(_vfs_nfs, 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 ncl_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
sysctl_iodmin(SYSCTL_HANDLER_ARGS)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 NFSLOCKIOD();
107 if (newmin > ncl_iodmax) {
108 error = EINVAL;
109 goto out;
110 }
111 nfs_iodmin = newmin;
112 if (ncl_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 - ncl_numasync; i > 0; i--)
119 nfs_nfsiodnew_sync();
120 out:
121 NFSUNLOCKIOD();
122 return (0);
123 }
124 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmin,
125 CTLTYPE_UINT | CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE,
126 0, sizeof (nfs_iodmin), sysctl_iodmin, "IU",
127 "Min number of nfsiod kthreads to keep as spares");
128
129 static int
sysctl_iodmax(SYSCTL_HANDLER_ARGS)130 sysctl_iodmax(SYSCTL_HANDLER_ARGS)
131 {
132 int error, i;
133 int iod, newmax;
134
135 newmax = ncl_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 NFSLOCKIOD();
142 ncl_iodmax = newmax;
143 if (ncl_numasync <= ncl_iodmax)
144 goto out;
145 /*
146 * If there are some asleep nfsiods that should
147 * exit, wakeup() them so that they check ncl_iodmax
148 * and exit. Those who are active will exit as
149 * soon as they finish I/O.
150 */
151 iod = ncl_numasync - 1;
152 for (i = 0; i < ncl_numasync - ncl_iodmax; i++) {
153 if (ncl_iodwant[iod] == NFSIOD_AVAILABLE)
154 wakeup(&ncl_iodwant[iod]);
155 iod--;
156 }
157 out:
158 NFSUNLOCKIOD();
159 return (0);
160 }
161 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax,
162 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, sizeof (ncl_iodmax),
163 sysctl_iodmax, "IU",
164 "Max number of nfsiod kthreads");
165
166 static int
nfs_nfsiodnew_sync(void)167 nfs_nfsiodnew_sync(void)
168 {
169 int error, i;
170
171 NFSASSERTIOD();
172 for (i = 0; i < ncl_iodmax; i++) {
173 if (nfs_asyncdaemon[i] == 0) {
174 nfs_asyncdaemon[i] = 1;
175 break;
176 }
177 }
178 if (i == ncl_iodmax)
179 return (0);
180 NFSUNLOCKIOD();
181 error = kproc_create(nfssvc_iod, nfs_asyncdaemon + i, NULL,
182 RFHIGHPID, 0, "newnfs %d", i);
183 NFSLOCKIOD();
184 if (error == 0) {
185 ncl_numasync++;
186 ncl_iodwant[i] = NFSIOD_AVAILABLE;
187 } else
188 nfs_asyncdaemon[i] = 0;
189 return (error);
190 }
191
192 void
ncl_nfsiodnew_tq(__unused void * arg,int pending)193 ncl_nfsiodnew_tq(__unused void *arg, int pending)
194 {
195
196 NFSLOCKIOD();
197 while (pending > 0) {
198 pending--;
199 nfs_nfsiodnew_sync();
200 }
201 NFSUNLOCKIOD();
202 }
203
204 void
ncl_nfsiodnew(void)205 ncl_nfsiodnew(void)
206 {
207
208 NFSASSERTIOD();
209 taskqueue_enqueue(taskqueue_thread, &ncl_nfsiodnew_task);
210 }
211
212 static void
nfsiod_setup(void * dummy)213 nfsiod_setup(void *dummy)
214 {
215 int error;
216
217 TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin);
218 nfscl_init();
219 NFSLOCKIOD();
220 /* Silently limit the start number of nfsiod's */
221 if (nfs_iodmin > NFS_MAXASYNCDAEMON)
222 nfs_iodmin = NFS_MAXASYNCDAEMON;
223
224 while (ncl_numasync < nfs_iodmin) {
225 error = nfs_nfsiodnew_sync();
226 if (error == -1)
227 panic("nfsiod_setup: nfs_nfsiodnew failed");
228 }
229 NFSUNLOCKIOD();
230 }
231 SYSINIT(newnfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
232
233 static int nfs_defect = 0;
234 SYSCTL_INT(_vfs_nfs, OID_AUTO, defect, CTLFLAG_RW, &nfs_defect, 0,
235 "Allow nfsiods to migrate serving different mounts");
236
237 /*
238 * Asynchronous I/O daemons for client nfs.
239 * They do read-ahead and write-behind operations on the block I/O cache.
240 * Returns if we hit the timeout defined by the iodmaxidle sysctl.
241 */
242 static void
nfssvc_iod(void * instance)243 nfssvc_iod(void *instance)
244 {
245 struct buf *bp;
246 struct nfsmount *nmp;
247 int myiod, timo;
248 int error = 0;
249
250 NFSLOCKIOD();
251 myiod = (int *)instance - nfs_asyncdaemon;
252 /*
253 * Main loop
254 */
255 for (;;) {
256 while (((nmp = ncl_iodmount[myiod]) == NULL)
257 || !TAILQ_FIRST(&nmp->nm_bufq)) {
258 if (myiod >= ncl_iodmax)
259 goto finish;
260 if (nmp)
261 nmp->nm_bufqiods--;
262 if (ncl_iodwant[myiod] == NFSIOD_NOT_AVAILABLE)
263 ncl_iodwant[myiod] = NFSIOD_AVAILABLE;
264 ncl_iodmount[myiod] = NULL;
265 /*
266 * Always keep at least nfs_iodmin kthreads.
267 */
268 timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz;
269 error = msleep(&ncl_iodwant[myiod], &ncl_iod_mutex, PWAIT | PCATCH,
270 "-", timo);
271 if (error) {
272 nmp = ncl_iodmount[myiod];
273 /*
274 * Rechecking the nm_bufq closes a rare race where the
275 * nfsiod is woken up at the exact time the idle timeout
276 * fires
277 */
278 if (nmp && TAILQ_FIRST(&nmp->nm_bufq))
279 error = 0;
280 break;
281 }
282 }
283 if (error)
284 break;
285 while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) {
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 <= ncl_numasync) {
290 nmp->nm_bufqwant = 0;
291 wakeup(&nmp->nm_bufq);
292 }
293 NFSUNLOCKIOD();
294 KASSERT((bp->b_flags & B_DIRECT) == 0,
295 ("nfssvc_iod: B_DIRECT set"));
296 if (bp->b_iocmd == BIO_READ)
297 (void) ncl_doio(bp->b_vp, bp, bp->b_rcred,
298 NULL, 0);
299 else
300 (void) ncl_doio(bp->b_vp, bp, bp->b_wcred,
301 NULL, 0);
302 NFSLOCKIOD();
303 /*
304 * Make sure the nmp hasn't been dismounted as soon as
305 * ncl_doio() completes for the last buffer.
306 */
307 nmp = ncl_iodmount[myiod];
308 if (nmp == NULL)
309 break;
310
311 /*
312 * If there are more than one iod on this mount, then defect
313 * so that the iods can be shared out fairly between the mounts
314 */
315 if (nfs_defect && nmp->nm_bufqiods > 1) {
316 NFS_DPF(ASYNCIO,
317 ("nfssvc_iod: iod %d defecting from mount %p\n",
318 myiod, nmp));
319 ncl_iodmount[myiod] = NULL;
320 nmp->nm_bufqiods--;
321 break;
322 }
323 }
324 }
325 finish:
326 nfs_asyncdaemon[myiod] = 0;
327 if (nmp)
328 nmp->nm_bufqiods--;
329 ncl_iodwant[myiod] = NFSIOD_NOT_AVAILABLE;
330 ncl_iodmount[myiod] = NULL;
331 /* Someone may be waiting for the last nfsiod to terminate. */
332 if (--ncl_numasync == 0)
333 wakeup(&ncl_numasync);
334 NFSUNLOCKIOD();
335 if ((error == 0) || (error == EWOULDBLOCK))
336 kproc_exit(0);
337 /* Abnormal termination */
338 kproc_exit(1);
339 }
340