nfs_clnfsiod.c

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    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/cdefs.h>
   38 __FBSDID("$FreeBSD$");
   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/vnode.h>
   47 #include <sys/malloc.h>
   48 #include <sys/mount.h>
   49 #include <sys/proc.h>
   50 #include <sys/bio.h>
   51 #include <sys/buf.h>
   52 #include <sys/mbuf.h>
   53 #include <sys/socket.h>
   54 #include <sys/socketvar.h>
   55 #include <sys/domain.h>
   56 #include <sys/protosw.h>
   57 #include <sys/namei.h>
   58 #include <sys/unistd.h>
   59 #include <sys/kthread.h>
   60 #include <sys/fcntl.h>
   61 #include <sys/lockf.h>
   62 #include <sys/mutex.h>
   63 #include <sys/taskqueue.h>
   64 
   65 #include <netinet/in.h>
   66 #include <netinet/tcp.h>
   67 
   68 #include <fs/nfs/nfsport.h>
   69 #include <fs/nfsclient/nfsmount.h>
   70 #include <fs/nfsclient/nfs.h>
   71 #include <fs/nfsclient/nfsnode.h>
   72 
   73 extern struct mtx       ncl_iod_mutex;
   74 extern struct task      ncl_nfsiodnew_task;
   75 
   76 int ncl_numasync;
   77 enum nfsiod_state ncl_iodwant[NFS_MAXASYNCDAEMON];
   78 struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON];
   79 
   80 static void     nfssvc_iod(void *);
   81 
   82 static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
   83 
   84 SYSCTL_DECL(_vfs_nfs);
   85 
   86 /* Maximum number of seconds a nfsiod kthread will sleep before exiting */
   87 static unsigned int nfs_iodmaxidle = 120;
   88 SYSCTL_UINT(_vfs_nfs, OID_AUTO, iodmaxidle, CTLFLAG_RW, &nfs_iodmaxidle, 0,
   89     "Max number of seconds an nfsiod kthread will sleep before exiting");
   90 
   91 /* Maximum number of nfsiod kthreads */
   92 unsigned int ncl_iodmax = 20;
   93 
   94 /* Minimum number of nfsiod kthreads to keep as spares */
   95 static unsigned int nfs_iodmin = 0;
   96 
   97 static int nfs_nfsiodnew_sync(void);
   98 
   99 static int
  100 sysctl_iodmin(SYSCTL_HANDLER_ARGS)
  101 {
  102         int error, i;
  103         int newmin;
  104 
  105         newmin = nfs_iodmin;
  106         error = sysctl_handle_int(oidp, &newmin, 0, req);
  107         if (error || (req->newptr == NULL))
  108                 return (error);
  109         NFSLOCKIOD();
  110         if (newmin > ncl_iodmax) {
  111                 error = EINVAL;
  112                 goto out;
  113         }
  114         nfs_iodmin = newmin;
  115         if (ncl_numasync >= nfs_iodmin)
  116                 goto out;
  117         /*
  118          * If the current number of nfsiod is lower
  119          * than the new minimum, create some more.
  120          */
  121         for (i = nfs_iodmin - ncl_numasync; i > 0; i--)
  122                 nfs_nfsiodnew_sync();
  123 out:
  124         NFSUNLOCKIOD(); 
  125         return (0);
  126 }
  127 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmin,
  128     CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, sizeof (nfs_iodmin),
  129     sysctl_iodmin, "IU",
  130     "Min number of nfsiod kthreads to keep as spares");
  131 
  132 static int
  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         NFSLOCKIOD();
  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         NFSUNLOCKIOD();
  162         return (0);
  163 }
  164 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax,
  165     CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, sizeof (ncl_iodmax),
  166     sysctl_iodmax, "IU",
  167     "Max number of nfsiod kthreads");
  168 
  169 static int
  170 nfs_nfsiodnew_sync(void)
  171 {
  172         int error, i;
  173 
  174         NFSASSERTIOD();
  175         for (i = 0; i < ncl_iodmax; i++) {
  176                 if (nfs_asyncdaemon[i] == 0) {
  177                         nfs_asyncdaemon[i] = 1;
  178                         break;
  179                 }
  180         }
  181         if (i == ncl_iodmax)
  182                 return (0);
  183         NFSUNLOCKIOD();
  184         error = kproc_create(nfssvc_iod, nfs_asyncdaemon + i, NULL,
  185             RFHIGHPID, 0, "newnfs %d", i);
  186         NFSLOCKIOD();
  187         if (error == 0) {
  188                 ncl_numasync++;
  189                 ncl_iodwant[i] = NFSIOD_AVAILABLE;
  190         } else
  191                 nfs_asyncdaemon[i] = 0;
  192         return (error);
  193 }
  194 
  195 void
  196 ncl_nfsiodnew_tq(__unused void *arg, int pending)
  197 {
  198 
  199         NFSLOCKIOD();
  200         while (pending > 0) {
  201                 pending--;
  202                 nfs_nfsiodnew_sync();
  203         }
  204         NFSUNLOCKIOD();
  205 }
  206 
  207 void
  208 ncl_nfsiodnew(void)
  209 {
  210 
  211         NFSASSERTIOD();
  212         taskqueue_enqueue(taskqueue_thread, &ncl_nfsiodnew_task);
  213 }
  214 
  215 static void
  216 nfsiod_setup(void *dummy)
  217 {
  218         int error;
  219 
  220         TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin);
  221         nfscl_init();
  222         NFSLOCKIOD();
  223         /* Silently limit the start number of nfsiod's */
  224         if (nfs_iodmin > NFS_MAXASYNCDAEMON)
  225                 nfs_iodmin = NFS_MAXASYNCDAEMON;
  226 
  227         while (ncl_numasync < nfs_iodmin) {
  228                 error = nfs_nfsiodnew_sync();
  229                 if (error == -1)
  230                         panic("nfsiod_setup: nfs_nfsiodnew failed");
  231         }
  232         NFSUNLOCKIOD();
  233 }
  234 SYSINIT(newnfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
  235 
  236 static int nfs_defect = 0;
  237 SYSCTL_INT(_vfs_nfs, OID_AUTO, defect, CTLFLAG_RW, &nfs_defect, 0,
  238     "Allow nfsiods to migrate serving different mounts");
  239 
  240 /*
  241  * Asynchronous I/O daemons for client nfs.
  242  * They do read-ahead and write-behind operations on the block I/O cache.
  243  * Returns if we hit the timeout defined by the iodmaxidle sysctl.
  244  */
  245 static void
  246 nfssvc_iod(void *instance)
  247 {
  248         struct buf *bp;
  249         struct nfsmount *nmp;
  250         int myiod, timo;
  251         int error = 0;
  252 
  253         NFSLOCKIOD();
  254         myiod = (int *)instance - nfs_asyncdaemon;
  255         /*
  256          * Main loop
  257          */
  258         for (;;) {
  259             while (((nmp = ncl_iodmount[myiod]) == NULL)
  260                    || !TAILQ_FIRST(&nmp->nm_bufq)) {
  261                 if (myiod >= ncl_iodmax)
  262                         goto finish;
  263                 if (nmp)
  264                         nmp->nm_bufqiods--;
  265                 if (ncl_iodwant[myiod] == NFSIOD_NOT_AVAILABLE)
  266                         ncl_iodwant[myiod] = NFSIOD_AVAILABLE;
  267                 ncl_iodmount[myiod] = NULL;
  268                 /*
  269                  * Always keep at least nfs_iodmin kthreads.
  270                  */
  271                 timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz;
  272                 error = msleep(&ncl_iodwant[myiod], &ncl_iod_mutex, PWAIT | PCATCH,
  273                     "-", timo);
  274                 if (error) {
  275                         nmp = ncl_iodmount[myiod];
  276                         /*
  277                          * Rechecking the nm_bufq closes a rare race where the 
  278                          * nfsiod is woken up at the exact time the idle timeout
  279                          * fires
  280                          */
  281                         if (nmp && TAILQ_FIRST(&nmp->nm_bufq))
  282                                 error = 0;
  283                         break;
  284                 }
  285             }
  286             if (error)
  287                     break;
  288             while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) {
  289                 /* Take one off the front of the list */
  290                 TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist);
  291                 nmp->nm_bufqlen--;
  292                 if (nmp->nm_bufqwant && nmp->nm_bufqlen <= ncl_numasync) {
  293                     nmp->nm_bufqwant = 0;
  294                     wakeup(&nmp->nm_bufq);
  295                 }
  296                 NFSUNLOCKIOD();
  297                 if (bp->b_flags & B_DIRECT) {
  298                         KASSERT((bp->b_iocmd == BIO_WRITE), ("nfscvs_iod: BIO_WRITE not set"));
  299                         (void)ncl_doio_directwrite(bp);
  300                 } else {
  301                         if (bp->b_iocmd == BIO_READ)
  302                                 (void) ncl_doio(bp->b_vp, bp, bp->b_rcred,
  303                                     NULL, 0);
  304                         else
  305                                 (void) ncl_doio(bp->b_vp, bp, bp->b_wcred,
  306                                     NULL, 0);
  307                 }
  308                 NFSLOCKIOD();
  309                 /*
  310                  * Make sure the nmp hasn't been dismounted as soon as
  311                  * ncl_doio() completes for the last buffer.
  312                  */
  313                 nmp = ncl_iodmount[myiod];
  314                 if (nmp == NULL)
  315                         break;
  316 
  317                 /*
  318                  * If there are more than one iod on this mount, then defect
  319                  * so that the iods can be shared out fairly between the mounts
  320                  */
  321                 if (nfs_defect && nmp->nm_bufqiods > 1) {
  322                     NFS_DPF(ASYNCIO,
  323                             ("nfssvc_iod: iod %d defecting from mount %p\n",
  324                              myiod, nmp));
  325                     ncl_iodmount[myiod] = NULL;
  326                     nmp->nm_bufqiods--;
  327                     break;
  328                 }
  329             }
  330         }
  331 finish:
  332         nfs_asyncdaemon[myiod] = 0;
  333         if (nmp)
  334             nmp->nm_bufqiods--;
  335         ncl_iodwant[myiod] = NFSIOD_NOT_AVAILABLE;
  336         ncl_iodmount[myiod] = NULL;
  337         /* Someone may be waiting for the last nfsiod to terminate. */
  338         if (--ncl_numasync == 0)
  339                 wakeup(&ncl_numasync);
  340         NFSUNLOCKIOD();
  341         if ((error == 0) || (error == EWOULDBLOCK))
  342                 kproc_exit(0);
  343         /* Abnormal termination */
  344         kproc_exit(1);
  345 }
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FreeBSD/Linux Kernel Cross Reference sys/fs/nfsclient/nfs_clnfsiod.c

FreeBSD/Linux Kernel Cross Reference
sys/fs/nfsclient/nfs_clnfsiod.c
