57bfe0a9f8
vnode lock and several locks needed during fork, like fd lock. Instead, schedule the task to be executed in the taskqueue context. We still waiting for the fork to finish, but the context of the thread executing the task does not make real LORs with our vnode lock. Submitted by: pluknet at gmail com Reviewed by: jhb Tested by: pho MFC after: 3 weeks
360 lines
9.7 KiB
C
360 lines
9.7 KiB
C
/*-
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Rick Macklem at The University of Guelph.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)nfs_syscalls.c 8.5 (Berkeley) 3/30/95
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/file.h>
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#include <sys/filedesc.h>
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#include <sys/vnode.h>
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#include <sys/malloc.h>
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#include <sys/mount.h>
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#include <sys/proc.h>
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#include <sys/bio.h>
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#include <sys/buf.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/domain.h>
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#include <sys/protosw.h>
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#include <sys/namei.h>
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#include <sys/unistd.h>
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#include <sys/kthread.h>
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#include <sys/fcntl.h>
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#include <sys/lockf.h>
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#include <sys/mutex.h>
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#include <sys/taskqueue.h>
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#include <netinet/in.h>
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#include <netinet/tcp.h>
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#include <nfs/xdr_subs.h>
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#include <nfs/nfsproto.h>
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#include <nfsclient/nfs.h>
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#include <nfsclient/nfsm_subs.h>
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#include <nfsclient/nfsmount.h>
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#include <nfsclient/nfsnode.h>
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#include <nfs/nfs_lock.h>
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static MALLOC_DEFINE(M_NFSSVC, "nfsclient_srvsock", "Nfs server structure");
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static void nfssvc_iod(void *);
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struct nfsiod_str {
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STAILQ_ENTRY(nfsiod_str) ni_links;
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int *ni_inst;
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int ni_iod;
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int ni_error;
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int ni_done;
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};
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static STAILQ_HEAD(, nfsiod_str) nfsiodhead =
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STAILQ_HEAD_INITIALIZER(nfsiodhead);
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static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
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SYSCTL_DECL(_vfs_nfs);
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/* Maximum number of seconds a nfsiod kthread will sleep before exiting */
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static unsigned int nfs_iodmaxidle = 120;
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SYSCTL_UINT(_vfs_nfs, OID_AUTO, iodmaxidle, CTLFLAG_RW, &nfs_iodmaxidle, 0,
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"Max number of seconds an nfsiod kthread will sleep before exiting");
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/* Maximum number of nfsiod kthreads */
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unsigned int nfs_iodmax = 20;
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/* Minimum number of nfsiod kthreads to keep as spares */
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static unsigned int nfs_iodmin = 0;
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static int
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sysctl_iodmin(SYSCTL_HANDLER_ARGS)
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{
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int error, i;
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int newmin;
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newmin = nfs_iodmin;
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error = sysctl_handle_int(oidp, &newmin, 0, req);
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if (error || (req->newptr == NULL))
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return (error);
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mtx_lock(&nfs_iod_mtx);
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if (newmin > nfs_iodmax) {
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error = EINVAL;
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goto out;
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}
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nfs_iodmin = newmin;
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if (nfs_numasync >= nfs_iodmin)
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goto out;
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/*
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* If the current number of nfsiod is lower
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* than the new minimum, create some more.
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*/
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for (i = nfs_iodmin - nfs_numasync; i > 0; i--)
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nfs_nfsiodnew(0);
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out:
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mtx_unlock(&nfs_iod_mtx);
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return (0);
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}
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SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmin, CTLTYPE_UINT | CTLFLAG_RW, 0,
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sizeof (nfs_iodmin), sysctl_iodmin, "IU",
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"Min number of nfsiod kthreads to keep as spares");
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static int
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sysctl_iodmax(SYSCTL_HANDLER_ARGS)
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{
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int error, i;
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int iod, newmax;
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newmax = nfs_iodmax;
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error = sysctl_handle_int(oidp, &newmax, 0, req);
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if (error || (req->newptr == NULL))
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return (error);
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if (newmax > NFS_MAXASYNCDAEMON)
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return (EINVAL);
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mtx_lock(&nfs_iod_mtx);
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nfs_iodmax = newmax;
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if (nfs_numasync <= nfs_iodmax)
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goto out;
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/*
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* If there are some asleep nfsiods that should
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* exit, wakeup() them so that they check nfs_iodmax
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* and exit. Those who are active will exit as
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* soon as they finish I/O.
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*/
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iod = nfs_numasync - 1;
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for (i = 0; i < nfs_numasync - nfs_iodmax; i++) {
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if (nfs_iodwant[iod] == NFSIOD_AVAILABLE)
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wakeup(&nfs_iodwant[iod]);
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iod--;
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}
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out:
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mtx_unlock(&nfs_iod_mtx);
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return (0);
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}
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SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
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sizeof (nfs_iodmax), sysctl_iodmax, "IU",
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"Max number of nfsiod kthreads");
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void
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nfs_nfsiodnew_tq(__unused void *arg, int pending)
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{
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struct nfsiod_str *nip;
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mtx_lock(&nfs_iod_mtx);
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while ((nip = STAILQ_FIRST(&nfsiodhead)) != NULL) {
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STAILQ_REMOVE_HEAD(&nfsiodhead, ni_links);
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mtx_unlock(&nfs_iod_mtx);
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nip->ni_error = kproc_create(nfssvc_iod, nip->ni_inst, NULL,
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RFHIGHPID, 0, "nfsiod %d", nip->ni_iod);
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nip->ni_done = 1;
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mtx_lock(&nfs_iod_mtx);
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wakeup(nip);
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}
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mtx_unlock(&nfs_iod_mtx);
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}
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int
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nfs_nfsiodnew(int set_iodwant)
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{
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int error, i;
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int newiod;
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struct nfsiod_str *nip;
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if (nfs_numasync >= nfs_iodmax)
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return (-1);
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newiod = -1;
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for (i = 0; i < nfs_iodmax; i++)
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if (nfs_asyncdaemon[i] == 0) {
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nfs_asyncdaemon[i]++;
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newiod = i;
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break;
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}
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if (newiod == -1)
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return (-1);
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if (set_iodwant > 0)
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nfs_iodwant[i] = NFSIOD_CREATED_FOR_NFS_ASYNCIO;
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mtx_unlock(&nfs_iod_mtx);
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nip = malloc(sizeof(*nip), M_TEMP, M_WAITOK | M_ZERO);
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nip->ni_inst = nfs_asyncdaemon + i;
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nip->ni_iod = newiod;
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mtx_lock(&nfs_iod_mtx);
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STAILQ_INSERT_TAIL(&nfsiodhead, nip, ni_links);
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taskqueue_enqueue(taskqueue_thread, &nfs_nfsiodnew_task);
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while (!nip->ni_done)
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mtx_sleep(nip, &nfs_iod_mtx, 0, "niwt", 0);
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error = nip->ni_error;
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free(nip, M_TEMP);
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if (error) {
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if (set_iodwant > 0)
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nfs_iodwant[i] = NFSIOD_NOT_AVAILABLE;
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return (-1);
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}
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nfs_numasync++;
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return (newiod);
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}
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static void
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nfsiod_setup(void *dummy)
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{
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int i;
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int error;
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TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin);
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mtx_lock(&nfs_iod_mtx);
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/* Silently limit the start number of nfsiod's */
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if (nfs_iodmin > NFS_MAXASYNCDAEMON)
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nfs_iodmin = NFS_MAXASYNCDAEMON;
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for (i = 0; i < nfs_iodmin; i++) {
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error = nfs_nfsiodnew(0);
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if (error == -1)
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panic("nfsiod_setup: nfs_nfsiodnew failed");
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}
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mtx_unlock(&nfs_iod_mtx);
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}
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SYSINIT(nfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
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static int nfs_defect = 0;
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SYSCTL_INT(_vfs_nfs, OID_AUTO, defect, CTLFLAG_RW, &nfs_defect, 0,
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"Allow nfsiods to migrate serving different mounts");
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/*
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* Asynchronous I/O daemons for client nfs.
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* They do read-ahead and write-behind operations on the block I/O cache.
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* Returns if we hit the timeout defined by the iodmaxidle sysctl.
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*/
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static void
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nfssvc_iod(void *instance)
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{
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struct buf *bp;
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struct nfsmount *nmp;
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int myiod, timo;
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int error = 0;
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mtx_lock(&nfs_iod_mtx);
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myiod = (int *)instance - nfs_asyncdaemon;
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/*
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* Main loop
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*/
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for (;;) {
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while (((nmp = nfs_iodmount[myiod]) == NULL)
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|| !TAILQ_FIRST(&nmp->nm_bufq)) {
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if (myiod >= nfs_iodmax)
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goto finish;
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if (nmp)
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nmp->nm_bufqiods--;
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if (nfs_iodwant[myiod] == NFSIOD_NOT_AVAILABLE)
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nfs_iodwant[myiod] = NFSIOD_AVAILABLE;
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nfs_iodmount[myiod] = NULL;
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/*
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* Always keep at least nfs_iodmin kthreads.
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*/
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timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz;
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error = msleep(&nfs_iodwant[myiod], &nfs_iod_mtx, PWAIT | PCATCH,
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"-", timo);
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if (error) {
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nmp = nfs_iodmount[myiod];
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/*
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* Rechecking the nm_bufq closes a rare race where the
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* nfsiod is woken up at the exact time the idle timeout
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* fires
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*/
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if (nmp && TAILQ_FIRST(&nmp->nm_bufq))
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error = 0;
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break;
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}
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}
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if (error)
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break;
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while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) {
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int giant_locked = 0;
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/* Take one off the front of the list */
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TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist);
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nmp->nm_bufqlen--;
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if (nmp->nm_bufqwant && nmp->nm_bufqlen <= nfs_numasync) {
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nmp->nm_bufqwant = 0;
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wakeup(&nmp->nm_bufq);
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}
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mtx_unlock(&nfs_iod_mtx);
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if (NFS_ISV4(bp->b_vp)) {
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giant_locked = 1;
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mtx_lock(&Giant);
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}
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if (bp->b_flags & B_DIRECT) {
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KASSERT((bp->b_iocmd == BIO_WRITE), ("nfscvs_iod: BIO_WRITE not set"));
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(void)nfs_doio_directwrite(bp);
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} else {
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if (bp->b_iocmd == BIO_READ)
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(void) nfs_doio(bp->b_vp, bp, bp->b_rcred, NULL);
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else
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(void) nfs_doio(bp->b_vp, bp, bp->b_wcred, NULL);
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}
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if (giant_locked)
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mtx_unlock(&Giant);
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mtx_lock(&nfs_iod_mtx);
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/*
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* If there are more than one iod on this mount, then defect
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* so that the iods can be shared out fairly between the mounts
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*/
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if (nfs_defect && nmp->nm_bufqiods > 1) {
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NFS_DPF(ASYNCIO,
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("nfssvc_iod: iod %d defecting from mount %p\n",
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myiod, nmp));
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nfs_iodmount[myiod] = NULL;
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nmp->nm_bufqiods--;
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break;
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}
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}
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}
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finish:
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nfs_asyncdaemon[myiod] = 0;
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if (nmp)
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nmp->nm_bufqiods--;
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nfs_iodwant[myiod] = NFSIOD_NOT_AVAILABLE;
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nfs_iodmount[myiod] = NULL;
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/* Someone may be waiting for the last nfsiod to terminate. */
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if (--nfs_numasync == 0)
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wakeup(&nfs_numasync);
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mtx_unlock(&nfs_iod_mtx);
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if ((error == 0) || (error == EWOULDBLOCK))
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kproc_exit(0);
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/* Abnormal termination */
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kproc_exit(1);
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}
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