1 /* $NetBSD: nfs_clnfsiod.c,v 1.2 2016/12/13 22:17:33 pgoyette Exp $ */
2 /*-
3 * Copyright (c) 1989, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * Rick Macklem at The University of Guelph.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * from nfs_syscalls.c 8.5 (Berkeley) 3/30/95
34 */
35
36 #include <sys/cdefs.h>
37 /* __FBSDID("FreeBSD: head/sys/fs/nfsclient/nfs_clnfsiod.c 249630 2013-04-18 23:20:16Z rmacklem "); */
38 __RCSID("$NetBSD: nfs_clnfsiod.c,v 1.2 2016/12/13 22:17:33 pgoyette Exp $");
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/sysproto.h>
43 #include <sys/kernel.h>
44 #include <sys/sysctl.h>
45 #include <sys/file.h>
46 #include <sys/filedesc.h>
47 #include <sys/vnode.h>
48 #include <sys/malloc.h>
49 #include <sys/mount.h>
50 #include <sys/proc.h>
51 #include <sys/bio.h>
52 #include <sys/buf.h>
53 #include <sys/mbuf.h>
54 #include <sys/socket.h>
55 #include <sys/socketvar.h>
56 #include <sys/domain.h>
57 #include <sys/protosw.h>
58 #include <sys/namei.h>
59 #include <sys/unistd.h>
60 #include <sys/kthread.h>
61 #include <sys/fcntl.h>
62 #include <sys/lockf.h>
63 #include <sys/mutex.h>
64 #include <sys/taskqueue.h>
65
66 #include <netinet/in.h>
67 #include <netinet/tcp.h>
68
69 #include <fs/nfs/common/nfsport.h>
70 #include <fs/nfs/client/nfsmount.h>
71 #include <fs/nfs/client/nfs.h>
72 #include <fs/nfs/client/nfsnode.h>
73
74 extern struct mtx ncl_iod_mutex;
75 extern struct task ncl_nfsiodnew_task;
76
77 int ncl_numasync;
78 enum nfsiod_state ncl_iodwant[NFS_MAXASYNCDAEMON];
79 struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON];
80
81 static void nfssvc_iod(void *);
82
83 static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
84
85 SYSCTL_DECL(_vfs_nfs);
86
87 /* Maximum number of seconds a nfsiod kthread will sleep before exiting */
88 static unsigned int nfs_iodmaxidle = 120;
89 SYSCTL_UINT(_vfs_nfs, OID_AUTO, iodmaxidle, CTLFLAG_RW, &nfs_iodmaxidle, 0,
90 "Max number of seconds an nfsiod kthread will sleep before exiting");
91
92 /* Maximum number of nfsiod kthreads */
93 unsigned int ncl_iodmax = 20;
94
95 /* Minimum number of nfsiod kthreads to keep as spares */
96 static unsigned int nfs_iodmin = 0;
97
98 static int nfs_nfsiodnew_sync(void);
99
100 static int
sysctl_iodmin(SYSCTL_HANDLER_ARGS)101 sysctl_iodmin(SYSCTL_HANDLER_ARGS)
102 {
103 int error, i;
104 int newmin;
105
106 newmin = nfs_iodmin;
107 error = sysctl_handle_int(oidp, &newmin, 0, req);
108 if (error || (req->newptr == NULL))
109 return (error);
110 mtx_lock(&ncl_iod_mutex);
111 if (newmin > ncl_iodmax) {
112 error = EINVAL;
113 goto out;
114 }
115 nfs_iodmin = newmin;
116 if (ncl_numasync >= nfs_iodmin)
117 goto out;
118 /*
119 * If the current number of nfsiod is lower
120 * than the new minimum, create some more.
121 */
122 for (i = nfs_iodmin - ncl_numasync; i > 0; i--)
123 nfs_nfsiodnew_sync();
124 out:
125 mtx_unlock(&ncl_iod_mutex);
126 return (0);
127 }
128 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmin, CTLTYPE_UINT | CTLFLAG_RW, 0,
129 sizeof (nfs_iodmin), sysctl_iodmin, "IU",
130 "Min number of nfsiod kthreads to keep as spares");
131
132 static int
sysctl_iodmax(SYSCTL_HANDLER_ARGS)133 sysctl_iodmax(SYSCTL_HANDLER_ARGS)
134 {
135 int error, i;
136 int iod, newmax;
137
138 newmax = ncl_iodmax;
139 error = sysctl_handle_int(oidp, &newmax, 0, req);
140 if (error || (req->newptr == NULL))
141 return (error);
142 if (newmax > NFS_MAXASYNCDAEMON)
143 return (EINVAL);
144 mtx_lock(&ncl_iod_mutex);
145 ncl_iodmax = newmax;
146 if (ncl_numasync <= ncl_iodmax)
147 goto out;
148 /*
149 * If there are some asleep nfsiods that should
150 * exit, wakeup() them so that they check ncl_iodmax
151 * and exit. Those who are active will exit as
152 * soon as they finish I/O.
153 */
154 iod = ncl_numasync - 1;
155 for (i = 0; i < ncl_numasync - ncl_iodmax; i++) {
156 if (ncl_iodwant[iod] == NFSIOD_AVAILABLE)
157 wakeup(&ncl_iodwant[iod]);
158 iod--;
159 }
160 out:
161 mtx_unlock(&ncl_iod_mutex);
162 return (0);
163 }
164 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
165 sizeof (ncl_iodmax), sysctl_iodmax, "IU",
166 "Max number of nfsiod kthreads");
167
168 static int
nfs_nfsiodnew_sync(void)169 nfs_nfsiodnew_sync(void)
170 {
171 int error, i;
172
173 mtx_assert(&ncl_iod_mutex, MA_OWNED);
174 for (i = 0; i < ncl_iodmax; i++) {
175 if (nfs_asyncdaemon[i] == 0) {
176 nfs_asyncdaemon[i] = 1;
177 break;
178 }
179 }
180 if (i == ncl_iodmax)
181 return (0);
182 mtx_unlock(&ncl_iod_mutex);
183 error = kproc_create(nfssvc_iod, nfs_asyncdaemon + i, NULL,
184 RFHIGHPID, 0, "newnfs %d", i);
185 mtx_lock(&ncl_iod_mutex);
186 if (error == 0) {
187 ncl_numasync++;
188 ncl_iodwant[i] = NFSIOD_AVAILABLE;
189 } else
190 nfs_asyncdaemon[i] = 0;
191 return (error);
192 }
193
194 void
ncl_nfsiodnew_tq(__unused void * arg,int pending)195 ncl_nfsiodnew_tq(__unused void *arg, int pending)
196 {
197
198 mtx_lock(&ncl_iod_mutex);
199 while (pending > 0) {
200 pending--;
201 nfs_nfsiodnew_sync();
202 }
203 mtx_unlock(&ncl_iod_mutex);
204 }
205
206 void
ncl_nfsiodnew(void)207 ncl_nfsiodnew(void)
208 {
209
210 mtx_assert(&ncl_iod_mutex, MA_OWNED);
211 taskqueue_enqueue(taskqueue_thread, &ncl_nfsiodnew_task);
212 }
213
214 static void
nfsiod_setup(void * dummy)215 nfsiod_setup(void *dummy)
216 {
217 int error;
218
219 TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin);
220 nfscl_init();
221 mtx_lock(&ncl_iod_mutex);
222 /* Silently limit the start number of nfsiod's */
223 if (nfs_iodmin > NFS_MAXASYNCDAEMON)
224 nfs_iodmin = NFS_MAXASYNCDAEMON;
225
226 while (ncl_numasync < nfs_iodmin) {
227 error = nfs_nfsiodnew_sync();
228 if (error == -1)
229 panic("nfsiod_setup: nfs_nfsiodnew failed");
230 }
231 mtx_unlock(&ncl_iod_mutex);
232 }
233 SYSINIT(newnfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
234
235 static int nfs_defect = 0;
236 SYSCTL_INT(_vfs_nfs, OID_AUTO, defect, CTLFLAG_RW, &nfs_defect, 0,
237 "Allow nfsiods to migrate serving different mounts");
238
239 /*
240 * Asynchronous I/O daemons for client nfs.
241 * They do read-ahead and write-behind operations on the block I/O cache.
242 * Returns if we hit the timeout defined by the iodmaxidle sysctl.
243 */
244 static void
nfssvc_iod(void * instance)245 nfssvc_iod(void *instance)
246 {
247 struct buf *bp;
248 struct nfsmount *nmp;
249 int myiod, timo;
250 int error = 0;
251
252 mtx_lock(&ncl_iod_mutex);
253 myiod = (int *)instance - nfs_asyncdaemon;
254 /*
255 * Main loop
256 */
257 for (;;) {
258 while (((nmp = ncl_iodmount[myiod]) == NULL)
259 || !TAILQ_FIRST(&nmp->nm_bufq)) {
260 if (myiod >= ncl_iodmax)
261 goto finish;
262 if (nmp)
263 nmp->nm_bufqiods--;
264 if (ncl_iodwant[myiod] == NFSIOD_NOT_AVAILABLE)
265 ncl_iodwant[myiod] = NFSIOD_AVAILABLE;
266 ncl_iodmount[myiod] = NULL;
267 /*
268 * Always keep at least nfs_iodmin kthreads.
269 */
270 timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz;
271 error = msleep(&ncl_iodwant[myiod], &ncl_iod_mutex, PWAIT | PCATCH,
272 "-", timo);
273 if (error) {
274 nmp = ncl_iodmount[myiod];
275 /*
276 * Rechecking the nm_bufq closes a rare race where the
277 * nfsiod is woken up at the exact time the idle timeout
278 * fires
279 */
280 if (nmp && TAILQ_FIRST(&nmp->nm_bufq))
281 error = 0;
282 break;
283 }
284 }
285 if (error)
286 break;
287 while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) {
288 /* Take one off the front of the list */
289 TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist);
290 nmp->nm_bufqlen--;
291 if (nmp->nm_bufqwant && nmp->nm_bufqlen <= ncl_numasync) {
292 nmp->nm_bufqwant = 0;
293 wakeup(&nmp->nm_bufq);
294 }
295 mtx_unlock(&ncl_iod_mutex);
296 if (bp->b_flags & B_DIRECT) {
297 KASSERT((bp->b_iocmd == BIO_WRITE), ("nfscvs_iod: BIO_WRITE not set"));
298 (void)ncl_doio_directwrite(bp);
299 } else {
300 if (bp->b_iocmd == BIO_READ)
301 (void) ncl_doio(bp->b_vp, bp, bp->b_rcred,
302 NULL, 0);
303 else
304 (void) ncl_doio(bp->b_vp, bp, bp->b_wcred,
305 NULL, 0);
306 }
307 mtx_lock(&ncl_iod_mutex);
308 /*
309 * Make sure the nmp hasn't been dismounted as soon as
310 * ncl_doio() completes for the last buffer.
311 */
312 nmp = ncl_iodmount[myiod];
313 if (nmp == NULL)
314 break;
315
316 /*
317 * If there are more than one iod on this mount, then defect
318 * so that the iods can be shared out fairly between the mounts
319 */
320 if (nfs_defect && nmp->nm_bufqiods > 1) {
321 NFS_DPF(ASYNCIO,
322 ("nfssvc_iod: iod %d defecting from mount %p\n",
323 myiod, nmp));
324 ncl_iodmount[myiod] = NULL;
325 nmp->nm_bufqiods--;
326 break;
327 }
328 }
329 }
330 finish:
331 nfs_asyncdaemon[myiod] = 0;
332 if (nmp)
333 nmp->nm_bufqiods--;
334 ncl_iodwant[myiod] = NFSIOD_NOT_AVAILABLE;
335 ncl_iodmount[myiod] = NULL;
336 /* Someone may be waiting for the last nfsiod to terminate. */
337 if (--ncl_numasync == 0)
338 wakeup(&ncl_numasync);
339 mtx_unlock(&ncl_iod_mutex);
340 if ((error == 0) || (error == EWOULDBLOCK))
341 kproc_exit(0);
342 /* Abnormal termination */
343 kproc_exit(1);
344 }
345