freebsd-dev/sys/fs/nfsclient/nfs_clnfsiod.c
Pedro F. Giffuni 51369649b0 sys: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:43:44 +00:00

344 lines
9.1 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Rick Macklem at The University of Guelph.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from nfs_syscalls.c 8.5 (Berkeley) 3/30/95
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/file.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/namei.h>
#include <sys/unistd.h>
#include <sys/kthread.h>
#include <sys/fcntl.h>
#include <sys/lockf.h>
#include <sys/mutex.h>
#include <sys/taskqueue.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <fs/nfs/nfsport.h>
#include <fs/nfsclient/nfsmount.h>
#include <fs/nfsclient/nfs.h>
#include <fs/nfsclient/nfsnode.h>
extern struct mtx ncl_iod_mutex;
extern struct task ncl_nfsiodnew_task;
int ncl_numasync;
enum nfsiod_state ncl_iodwant[NFS_MAXASYNCDAEMON];
struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON];
static void nfssvc_iod(void *);
static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
SYSCTL_DECL(_vfs_nfs);
/* Maximum number of seconds a nfsiod kthread will sleep before exiting */
static unsigned int nfs_iodmaxidle = 120;
SYSCTL_UINT(_vfs_nfs, OID_AUTO, iodmaxidle, CTLFLAG_RW, &nfs_iodmaxidle, 0,
"Max number of seconds an nfsiod kthread will sleep before exiting");
/* Maximum number of nfsiod kthreads */
unsigned int ncl_iodmax = 20;
/* Minimum number of nfsiod kthreads to keep as spares */
static unsigned int nfs_iodmin = 0;
static int nfs_nfsiodnew_sync(void);
static int
sysctl_iodmin(SYSCTL_HANDLER_ARGS)
{
int error, i;
int newmin;
newmin = nfs_iodmin;
error = sysctl_handle_int(oidp, &newmin, 0, req);
if (error || (req->newptr == NULL))
return (error);
mtx_lock(&ncl_iod_mutex);
if (newmin > ncl_iodmax) {
error = EINVAL;
goto out;
}
nfs_iodmin = newmin;
if (ncl_numasync >= nfs_iodmin)
goto out;
/*
* If the current number of nfsiod is lower
* than the new minimum, create some more.
*/
for (i = nfs_iodmin - ncl_numasync; i > 0; i--)
nfs_nfsiodnew_sync();
out:
mtx_unlock(&ncl_iod_mutex);
return (0);
}
SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmin, CTLTYPE_UINT | CTLFLAG_RW, 0,
sizeof (nfs_iodmin), sysctl_iodmin, "IU",
"Min number of nfsiod kthreads to keep as spares");
static int
sysctl_iodmax(SYSCTL_HANDLER_ARGS)
{
int error, i;
int iod, newmax;
newmax = ncl_iodmax;
error = sysctl_handle_int(oidp, &newmax, 0, req);
if (error || (req->newptr == NULL))
return (error);
if (newmax > NFS_MAXASYNCDAEMON)
return (EINVAL);
mtx_lock(&ncl_iod_mutex);
ncl_iodmax = newmax;
if (ncl_numasync <= ncl_iodmax)
goto out;
/*
* If there are some asleep nfsiods that should
* exit, wakeup() them so that they check ncl_iodmax
* and exit. Those who are active will exit as
* soon as they finish I/O.
*/
iod = ncl_numasync - 1;
for (i = 0; i < ncl_numasync - ncl_iodmax; i++) {
if (ncl_iodwant[iod] == NFSIOD_AVAILABLE)
wakeup(&ncl_iodwant[iod]);
iod--;
}
out:
mtx_unlock(&ncl_iod_mutex);
return (0);
}
SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
sizeof (ncl_iodmax), sysctl_iodmax, "IU",
"Max number of nfsiod kthreads");
static int
nfs_nfsiodnew_sync(void)
{
int error, i;
mtx_assert(&ncl_iod_mutex, MA_OWNED);
for (i = 0; i < ncl_iodmax; i++) {
if (nfs_asyncdaemon[i] == 0) {
nfs_asyncdaemon[i] = 1;
break;
}
}
if (i == ncl_iodmax)
return (0);
mtx_unlock(&ncl_iod_mutex);
error = kproc_create(nfssvc_iod, nfs_asyncdaemon + i, NULL,
RFHIGHPID, 0, "newnfs %d", i);
mtx_lock(&ncl_iod_mutex);
if (error == 0) {
ncl_numasync++;
ncl_iodwant[i] = NFSIOD_AVAILABLE;
} else
nfs_asyncdaemon[i] = 0;
return (error);
}
void
ncl_nfsiodnew_tq(__unused void *arg, int pending)
{
mtx_lock(&ncl_iod_mutex);
while (pending > 0) {
pending--;
nfs_nfsiodnew_sync();
}
mtx_unlock(&ncl_iod_mutex);
}
void
ncl_nfsiodnew(void)
{
mtx_assert(&ncl_iod_mutex, MA_OWNED);
taskqueue_enqueue(taskqueue_thread, &ncl_nfsiodnew_task);
}
static void
nfsiod_setup(void *dummy)
{
int error;
TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin);
nfscl_init();
mtx_lock(&ncl_iod_mutex);
/* Silently limit the start number of nfsiod's */
if (nfs_iodmin > NFS_MAXASYNCDAEMON)
nfs_iodmin = NFS_MAXASYNCDAEMON;
while (ncl_numasync < nfs_iodmin) {
error = nfs_nfsiodnew_sync();
if (error == -1)
panic("nfsiod_setup: nfs_nfsiodnew failed");
}
mtx_unlock(&ncl_iod_mutex);
}
SYSINIT(newnfsiod, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, nfsiod_setup, NULL);
static int nfs_defect = 0;
SYSCTL_INT(_vfs_nfs, OID_AUTO, defect, CTLFLAG_RW, &nfs_defect, 0,
"Allow nfsiods to migrate serving different mounts");
/*
* Asynchronous I/O daemons for client nfs.
* They do read-ahead and write-behind operations on the block I/O cache.
* Returns if we hit the timeout defined by the iodmaxidle sysctl.
*/
static void
nfssvc_iod(void *instance)
{
struct buf *bp;
struct nfsmount *nmp;
int myiod, timo;
int error = 0;
mtx_lock(&ncl_iod_mutex);
myiod = (int *)instance - nfs_asyncdaemon;
/*
* Main loop
*/
for (;;) {
while (((nmp = ncl_iodmount[myiod]) == NULL)
|| !TAILQ_FIRST(&nmp->nm_bufq)) {
if (myiod >= ncl_iodmax)
goto finish;
if (nmp)
nmp->nm_bufqiods--;
if (ncl_iodwant[myiod] == NFSIOD_NOT_AVAILABLE)
ncl_iodwant[myiod] = NFSIOD_AVAILABLE;
ncl_iodmount[myiod] = NULL;
/*
* Always keep at least nfs_iodmin kthreads.
*/
timo = (myiod < nfs_iodmin) ? 0 : nfs_iodmaxidle * hz;
error = msleep(&ncl_iodwant[myiod], &ncl_iod_mutex, PWAIT | PCATCH,
"-", timo);
if (error) {
nmp = ncl_iodmount[myiod];
/*
* Rechecking the nm_bufq closes a rare race where the
* nfsiod is woken up at the exact time the idle timeout
* fires
*/
if (nmp && TAILQ_FIRST(&nmp->nm_bufq))
error = 0;
break;
}
}
if (error)
break;
while ((bp = TAILQ_FIRST(&nmp->nm_bufq)) != NULL) {
/* Take one off the front of the list */
TAILQ_REMOVE(&nmp->nm_bufq, bp, b_freelist);
nmp->nm_bufqlen--;
if (nmp->nm_bufqwant && nmp->nm_bufqlen <= ncl_numasync) {
nmp->nm_bufqwant = 0;
wakeup(&nmp->nm_bufq);
}
mtx_unlock(&ncl_iod_mutex);
if (bp->b_flags & B_DIRECT) {
KASSERT((bp->b_iocmd == BIO_WRITE), ("nfscvs_iod: BIO_WRITE not set"));
(void)ncl_doio_directwrite(bp);
} else {
if (bp->b_iocmd == BIO_READ)
(void) ncl_doio(bp->b_vp, bp, bp->b_rcred,
NULL, 0);
else
(void) ncl_doio(bp->b_vp, bp, bp->b_wcred,
NULL, 0);
}
mtx_lock(&ncl_iod_mutex);
/*
* Make sure the nmp hasn't been dismounted as soon as
* ncl_doio() completes for the last buffer.
*/
nmp = ncl_iodmount[myiod];
if (nmp == NULL)
break;
/*
* If there are more than one iod on this mount, then defect
* so that the iods can be shared out fairly between the mounts
*/
if (nfs_defect && nmp->nm_bufqiods > 1) {
NFS_DPF(ASYNCIO,
("nfssvc_iod: iod %d defecting from mount %p\n",
myiod, nmp));
ncl_iodmount[myiod] = NULL;
nmp->nm_bufqiods--;
break;
}
}
}
finish:
nfs_asyncdaemon[myiod] = 0;
if (nmp)
nmp->nm_bufqiods--;
ncl_iodwant[myiod] = NFSIOD_NOT_AVAILABLE;
ncl_iodmount[myiod] = NULL;
/* Someone may be waiting for the last nfsiod to terminate. */
if (--ncl_numasync == 0)
wakeup(&ncl_numasync);
mtx_unlock(&ncl_iod_mutex);
if ((error == 0) || (error == EWOULDBLOCK))
kproc_exit(0);
/* Abnormal termination */
kproc_exit(1);
}