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 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 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 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 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 205 ncl_nfsiodnew(void) 206 { 207 208 NFSASSERTIOD(); 209 taskqueue_enqueue(taskqueue_thread, &ncl_nfsiodnew_task); 210 } 211 212 static void 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 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