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 * from nfs_syscalls.c 8.5 (Berkeley) 3/30/95
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD: head/sys/fs/nfsclient/nfs_clnfsiod.c 220683 2011-04-15 23:07:48Z 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 <fs/nfs/nfsport.h>
68#include <fs/nfsclient/nfsmount.h>
69#include <fs/nfsclient/nfs.h>
70#include <fs/nfsclient/nfsnode.h>
71
72extern struct mtx ncl_iod_mutex;
73extern struct task ncl_nfsiodnew_task;
74
75int ncl_numasync;
76enum nfsiod_state ncl_iodwant[NFS_MAXASYNCDAEMON];
77struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON];
78
79static void nfssvc_iod(void *);
80
81static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
82
83SYSCTL_DECL(_vfs_newnfs);
84
85/* Maximum number of seconds a nfsiod kthread will sleep before exiting */
86static unsigned int nfs_iodmaxidle = 120;
87SYSCTL_UINT(_vfs_newnfs, OID_AUTO, iodmaxidle, CTLFLAG_RW, &nfs_iodmaxidle, 0,
88 "Max number of seconds an nfsiod kthread will sleep before exiting");
89
90/* Maximum number of nfsiod kthreads */
91unsigned int ncl_iodmax = 20;
92
93/* Minimum number of nfsiod kthreads to keep as spares */
94static unsigned int nfs_iodmin = 0;
95
96static int nfs_nfsiodnew_sync(void);
97
98static int
99sysctl_iodmin(SYSCTL_HANDLER_ARGS)
100{
101 int error, i;
102 int newmin;
103
104 newmin = nfs_iodmin;
105 error = sysctl_handle_int(oidp, &newmin, 0, req);
106 if (error || (req->newptr == NULL))
107 return (error);
108 mtx_lock(&ncl_iod_mutex);
109 if (newmin > ncl_iodmax) {
110 error = EINVAL;
111 goto out;
112 }
113 nfs_iodmin = newmin;
114 if (ncl_numasync >= nfs_iodmin)
115 goto out;
116 /*
117 * If the current number of nfsiod is lower
118 * than the new minimum, create some more.
119 */
120 for (i = nfs_iodmin - ncl_numasync; i > 0; i--)
121 nfs_nfsiodnew_sync();
122out:
123 mtx_unlock(&ncl_iod_mutex);
124 return (0);
125}
126SYSCTL_PROC(_vfs_newnfs, OID_AUTO, iodmin, CTLTYPE_UINT | CTLFLAG_RW, 0,
127 sizeof (nfs_iodmin), sysctl_iodmin, "IU",
128 "Min number of nfsiod kthreads to keep as spares");
129
130static int
131sysctl_iodmax(SYSCTL_HANDLER_ARGS)
132{
133 int error, i;
134 int iod, newmax;
135
136 newmax = ncl_iodmax;
137 error = sysctl_handle_int(oidp, &newmax, 0, req);
138 if (error || (req->newptr == NULL))
139 return (error);
140 if (newmax > NFS_MAXASYNCDAEMON)
141 return (EINVAL);
142 mtx_lock(&ncl_iod_mutex);
143 ncl_iodmax = newmax;
144 if (ncl_numasync <= ncl_iodmax)
145 goto out;
146 /*
147 * If there are some asleep nfsiods that should
148 * exit, wakeup() them so that they check ncl_iodmax
149 * and exit. Those who are active will exit as
150 * soon as they finish I/O.
151 */
152 iod = ncl_numasync - 1;
153 for (i = 0; i < ncl_numasync - ncl_iodmax; i++) {
154 if (ncl_iodwant[iod] == NFSIOD_AVAILABLE)
155 wakeup(&ncl_iodwant[iod]);
156 iod--;
157 }
158out:
159 mtx_unlock(&ncl_iod_mutex);
160 return (0);
161}
162SYSCTL_PROC(_vfs_newnfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
163 sizeof (ncl_iodmax), sysctl_iodmax, "IU",
164 "Max number of nfsiod kthreads");
165
166static int
167nfs_nfsiodnew_sync(void)
168{
169 int error, i;
170
171 mtx_assert(&ncl_iod_mutex, MA_OWNED);
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 mtx_unlock(&ncl_iod_mutex);
181 error = kproc_create(nfssvc_iod, nfs_asyncdaemon + i, NULL,
182 RFHIGHPID, 0, "newnfs %d", i);
183 mtx_lock(&ncl_iod_mutex);
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
192void
193ncl_nfsiodnew_tq(__unused void *arg, int pending)
194{
195
196 mtx_lock(&ncl_iod_mutex);
197 while (pending > 0) {
198 pending--;
199 nfs_nfsiodnew_sync();
200 }
201 mtx_unlock(&ncl_iod_mutex);
202}
203
204void
205ncl_nfsiodnew(void)
206{
207
208 mtx_assert(&ncl_iod_mutex, MA_OWNED);
209 taskqueue_enqueue(taskqueue_thread, &ncl_nfsiodnew_task);
210}
211
212static void
213nfsiod_setup(void *dummy)
214{
215 int error;
216
217 TUNABLE_INT_FETCH("vfs.newnfs.iodmin", &nfs_iodmin);
218 nfscl_init();
219 mtx_lock(&ncl_iod_mutex);
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 mtx_unlock(&ncl_iod_mutex);
230}
231SYSINIT(newnfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
232
233static int nfs_defect = 0;
234SYSCTL_INT(_vfs_newnfs, 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 */
242static void
243nfssvc_iod(void *instance)
244{
245 struct buf *bp;
246 struct nfsmount *nmp;
247 int myiod, timo;
248 int error = 0;
249
250 mtx_lock(&ncl_iod_mutex);
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 mtx_unlock(&ncl_iod_mutex);
294 if (bp->b_flags & B_DIRECT) {
295 KASSERT((bp->b_iocmd == BIO_WRITE), ("nfscvs_iod: BIO_WRITE not set"));
296 (void)ncl_doio_directwrite(bp);
297 } else {
298 if (bp->b_iocmd == BIO_READ)
299 (void) ncl_doio(bp->b_vp, bp, bp->b_rcred,
300 NULL, 0);
301 else
302 (void) ncl_doio(bp->b_vp, bp, bp->b_wcred,
303 NULL, 0);
304 }
305 mtx_lock(&ncl_iod_mutex);
306 /*
307 * If there are more than one iod on this mount, then defect
308 * so that the iods can be shared out fairly between the mounts
309 */
310 if (nfs_defect && nmp->nm_bufqiods > 1) {
311 NFS_DPF(ASYNCIO,
312 ("nfssvc_iod: iod %d defecting from mount %p\n",
313 myiod, nmp));
314 ncl_iodmount[myiod] = NULL;
315 nmp->nm_bufqiods--;
316 break;
317 }
318 }
319 }
320finish:
321 nfs_asyncdaemon[myiod] = 0;
322 if (nmp)
323 nmp->nm_bufqiods--;
324 ncl_iodwant[myiod] = NFSIOD_NOT_AVAILABLE;
325 ncl_iodmount[myiod] = NULL;
326 /* Someone may be waiting for the last nfsiod to terminate. */
327 if (--ncl_numasync == 0)
328 wakeup(&ncl_numasync);
329 mtx_unlock(&ncl_iod_mutex);
330 if ((error == 0) || (error == EWOULDBLOCK))
331 kproc_exit(0);
332 /* Abnormal termination */
333 kproc_exit(1);
334}