nfs_nfsiod.c

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    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  * 3. All advertising materials mentioning features or use of this software
   17  *    must display the following acknowledgement:
   18  *      This product includes software developed by the University of
   19  *      California, Berkeley and its contributors.
   20  * 4. Neither the name of the University nor the names of its contributors
   21  *    may be used to endorse or promote products derived from this software
   22  *    without specific prior written permission.
   23  *
   24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   34  * SUCH DAMAGE.
   35  *
   36  *      @(#)nfs_syscalls.c      8.5 (Berkeley) 3/30/95
   37  */
   38 
   39 #include <sys/cdefs.h>
   40 __FBSDID("$FreeBSD: releng/5.2/sys/nfsclient/nfs_nfsiod.c 122698 2003-11-14 20:54:10Z alfred $");
   41 
   42 #include <sys/param.h>
   43 #include <sys/systm.h>
   44 #include <sys/sysproto.h>
   45 #include <sys/kernel.h>
   46 #include <sys/sysctl.h>
   47 #include <sys/file.h>
   48 #include <sys/filedesc.h>
   49 #include <sys/vnode.h>
   50 #include <sys/malloc.h>
   51 #include <sys/mount.h>
   52 #include <sys/proc.h>
   53 #include <sys/bio.h>
   54 #include <sys/buf.h>
   55 #include <sys/mbuf.h>
   56 #include <sys/socket.h>
   57 #include <sys/socketvar.h>
   58 #include <sys/domain.h>
   59 #include <sys/protosw.h>
   60 #include <sys/namei.h>
   61 #include <sys/unistd.h>
   62 #include <sys/kthread.h>
   63 #include <sys/fcntl.h>
   64 #include <sys/lockf.h>
   65 #include <sys/mutex.h>
   66 
   67 #include <netinet/in.h>
   68 #include <netinet/tcp.h>
   69 
   70 #include <rpc/rpcclnt.h>
   71 
   72 #include <nfs/xdr_subs.h>
   73 #include <nfs/rpcv2.h>
   74 #include <nfs/nfsproto.h>
   75 #include <nfsclient/nfs.h>
   76 #include <nfsclient/nfsm_subs.h>
   77 #include <nfsclient/nfsmount.h>
   78 #include <nfsclient/nfsnode.h>
   79 #include <nfsclient/nfs_lock.h>
   80 
   81 static MALLOC_DEFINE(M_NFSSVC, "NFS srvsock", "Nfs server structure");
   82 
   83 static void     nfssvc_iod(void *);
   84 
   85 static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
   86 
   87 SYSCTL_DECL(_vfs_nfs);
   88 
   89 /* Maximum number of seconds a nfsiod kthread will sleep before exiting */
   90 static unsigned int nfs_iodmaxidle = 120;
   91 SYSCTL_UINT(_vfs_nfs, OID_AUTO, iodmaxidle, CTLFLAG_RW, &nfs_iodmaxidle, 0, "");
   92 
   93 /* Maximum number of nfsiod kthreads */
   94 static unsigned int nfs_iodmax = 20;
   95 
   96 /* Minimum number of nfsiod kthreads to keep as spares */
   97 static unsigned int nfs_iodmin = 4;
   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         if (newmin > nfs_iodmax)
  110                 return (EINVAL);
  111         nfs_iodmin = newmin;
  112         if (nfs_numasync >= nfs_iodmin)
  113                 return (0);
  114         /*
  115          * If the current number of nfsiod is lower
  116          * than the new minimum, create some more.
  117          */
  118         for (i = nfs_iodmin - nfs_numasync; i > 0; i--)
  119                 nfs_nfsiodnew();
  120         return (0);
  121 }
  122 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmin, CTLTYPE_UINT | CTLFLAG_RW, 0,
  123     sizeof (nfs_iodmin), sysctl_iodmin, "IU", "");
  124 
  125 
  126 static int
  127 sysctl_iodmax(SYSCTL_HANDLER_ARGS)
  128 {
  129         int error, i;
  130         int iod, newmax;
  131 
  132         newmax = nfs_iodmax;
  133         error = sysctl_handle_int(oidp, &newmax, 0, req);
  134         if (error || (req->newptr == NULL))
  135                 return (error);
  136         if (newmax > NFS_MAXASYNCDAEMON)
  137                 return (EINVAL);
  138         nfs_iodmax = newmax;
  139         if (nfs_numasync <= nfs_iodmax)
  140                 return (0);
  141         /*
  142          * If there are some asleep nfsiods that should
  143          * exit, wakeup() them so that they check nfs_iodmax
  144          * and exit.  Those who are active will exit as
  145          * soon as they finish I/O.
  146          */
  147         iod = nfs_numasync - 1;
  148         for (i = 0; i < nfs_numasync - nfs_iodmax; i++) {
  149                 if (nfs_iodwant[iod])
  150                         wakeup(&nfs_iodwant[iod]);
  151                 iod--;
  152         }
  153         return (0);
  154 }
  155 SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
  156     sizeof (nfs_iodmax), sysctl_iodmax, "IU", "");
  157 
  158 int
  159 nfs_nfsiodnew(void)
  160 {
  161         int error, i;
  162         int newiod;
  163 
  164         if (nfs_numasync >= nfs_iodmax)
  165                 return (-1);
  166         newiod = -1;
  167         for (i = 0; i < nfs_iodmax; i++)
  168                 if (nfs_asyncdaemon[i] == 0) {
  169                         nfs_asyncdaemon[i]++;
  170                         newiod = i;
  171                         break;
  172                 }
  173         if (newiod == -1)
  174                 return (-1);
  175         error = kthread_create(nfssvc_iod, nfs_asyncdaemon + i, NULL, RFHIGHPID,
  176             0, "nfsiod %d", newiod);
  177         if (error)
  178                 return (-1);
  179         nfs_numasync++;
  180         return (newiod);
  181 }
  182 
  183 static void
  184 nfsiod_setup(void *dummy)
  185 {
  186         int i;
  187         int error;
  188 
  189         TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin);
  190         /* Silently limit the start number of nfsiod's */
  191         if (nfs_iodmin > NFS_MAXASYNCDAEMON)
  192                 nfs_iodmin = NFS_MAXASYNCDAEMON;
  193 
  194         for (i = 0; i < nfs_iodmin; i++) {
  195                 error = nfs_nfsiodnew();
  196                 if (error == -1)
  197                         panic("nfsiod_setup: nfs_nfsiodnew failed");
  198         }
  199 }
  200 SYSINIT(nfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
  201 
  202 static int nfs_defect = 0;
  203 SYSCTL_INT(_vfs_nfs, OID_AUTO, defect, CTLFLAG_RW, &nfs_defect, 0, "");
  204 
  205 int
  206 nfsclnt(struct thread *td, struct nfsclnt_args *uap)
  207 {
  208         struct lockd_ans la;
  209         int error;
  210 
  211         if ((uap->flag & NFSCLNT_LOCKDANS) != 0) {
  212                 error = copyin(uap->argp, &la, sizeof(la));
  213                 return (error != 0 ? error : nfslockdans(td, &la));
  214         }
  215         return EINVAL;
  216 }
  217 
  218 /*
  219  * Asynchronous I/O daemons for client nfs.
  220  * They do read-ahead and write-behind operations on the block I/O cache.
  221  * Returns if we hit the timeout defined by the iodmaxidle sysctl.
  222  */
  223 static void
  224 nfssvc_iod(void *instance)
  225 {
  226         struct buf *bp;
  227         struct nfsmount *nmp;
  228         int myiod, timo;
  229         int error = 0;
  230 
  231         mtx_lock(&Giant);
  232         myiod = (int *)instance - nfs_asyncdaemon;
  233         /*
  234          * Main loop
  235          */
  236         for (;;) {
  237             while (((nmp = nfs_iodmount[myiod]) == NULL
  238                    || !TAILQ_FIRST(&nmp->nm_bufq))
  239                    && error == 0) {
  240                 if (myiod >= nfs_iodmax)
  241                         goto finish;
  242                 if (nmp)
  243                         nmp->nm_bufqiods--;
  244                 nfs_iodwant[myiod] = curthread->td_proc;
  245                 nfs_iodmount[myiod] = NULL;
  246                 /*
  247                  * Always keep at least nfs_iodmin kthreads.
  248                  */
  249                 timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz;
  250                 error = tsleep(&nfs_iodwant[myiod], PWAIT | PCATCH,
  251                     "-", timo);
  252             }
  253             if (error)
  254                     break;
  255             while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) {
  256                 /* Take one off the front of the list */
  257                 TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist);
  258                 nmp->nm_bufqlen--;
  259                 if (nmp->nm_bufqwant && nmp->nm_bufqlen <= nfs_numasync) {
  260                     nmp->nm_bufqwant = 0;
  261                     wakeup(&nmp->nm_bufq);
  262                 }
  263                 if (bp->b_iocmd == BIO_READ)
  264                     (void) nfs_doio(bp, bp->b_rcred, NULL);
  265                 else
  266                     (void) nfs_doio(bp, bp->b_wcred, NULL);
  267                 /*
  268                  * If there are more than one iod on this mount, then defect
  269                  * so that the iods can be shared out fairly between the mounts
  270                  */
  271                 if (nfs_defect && nmp->nm_bufqiods > 1) {
  272                     NFS_DPF(ASYNCIO,
  273                             ("nfssvc_iod: iod %d defecting from mount %p\n",
  274                              myiod, nmp));
  275                     nfs_iodmount[myiod] = NULL;
  276                     nmp->nm_bufqiods--;
  277                     break;
  278                 }
  279             }
  280         }
  281 finish:
  282         nfs_asyncdaemon[myiod] = 0;
  283         if (nmp)
  284             nmp->nm_bufqiods--;
  285         nfs_iodwant[myiod] = NULL;
  286         nfs_iodmount[myiod] = NULL;
  287         nfs_numasync--;
  288         if ((error == 0) || (error == EWOULDBLOCK))
  289                 kthread_exit(0);
  290         /* Abnormal termination */
  291         kthread_exit(1);
  292 }
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FreeBSD/Linux Kernel Cross Reference sys/nfsclient/nfs_nfsiod.c

FreeBSD/Linux Kernel Cross Reference
sys/nfsclient/nfs_nfsiod.c
